net/ipv6/route.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Linux INET6 implementation
   4  *      FIB front-end.
   5  *
   6  *      Authors:
   7  *      Pedro Roque             <roque@di.fc.ul.pt>
   8  */
   9
  10 /*      Changes:
  11  *
  12  *      YOSHIFUJI Hideaki @USAGI
  13  *              reworked default router selection.
  14  *              - respect outgoing interface
  15  *              - select from (probably) reachable routers (i.e.
  16  *              routers in REACHABLE, STALE, DELAY or PROBE states).
  17  *              - always select the same router if it is (probably)
  18  *              reachable.  otherwise, round-robin the list.
  19  *      Ville Nuorvala
  20  *              Fixed routing subtrees.
  21  */
  22
  23 #define pr_fmt(fmt) "IPv6: " fmt
  24
  25 #include <linux/capability.h>
  26 #include <linux/errno.h>
  27 #include <linux/export.h>
  28 #include <linux/types.h>
  29 #include <linux/times.h>
  30 #include <linux/socket.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/route.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/in6.h>
  36 #include <linux/mroute6.h>
  37 #include <linux/init.h>
  38 #include <linux/if_arp.h>
  39 #include <linux/proc_fs.h>
  40 #include <linux/seq_file.h>
  41 #include <linux/nsproxy.h>
  42 #include <linux/slab.h>
  43 #include <linux/jhash.h>
  44 #include <net/net_namespace.h>
  45 #include <net/snmp.h>
  46 #include <net/ipv6.h>
  47 #include <net/ip6_fib.h>
  48 #include <net/ip6_route.h>
  49 #include <net/ndisc.h>
  50 #include <net/addrconf.h>
  51 #include <net/tcp.h>
  52 #include <linux/rtnetlink.h>
  53 #include <net/dst.h>
  54 #include <net/dst_metadata.h>
  55 #include <net/xfrm.h>
  56 #include <net/netevent.h>
  57 #include <net/netlink.h>
  58 #include <net/rtnh.h>
  59 #include <net/lwtunnel.h>
  60 #include <net/ip_tunnels.h>
  61 #include <net/l3mdev.h>
  62 #include <net/ip.h>
  63 #include <linux/uaccess.h>
  64
  65 #ifdef CONFIG_SYSCTL
  66 #include <linux/sysctl.h>
  67 #endif
  68
  69 static int ip6_rt_type_to_error(u8 fib6_type);
  70
  71 #define CREATE_TRACE_POINTS
  72 #include <trace/events/fib6.h>
  73 EXPORT_TRACEPOINT_SYMBOL_GPL(fib6_table_lookup);
  74 #undef CREATE_TRACE_POINTS
  75
  76 enum rt6_nud_state {
  77         RT6_NUD_FAIL_HARD = -3,
  78         RT6_NUD_FAIL_PROBE = -2,
  79         RT6_NUD_FAIL_DO_RR = -1,
  80         RT6_NUD_SUCCEED = 1
  81 };
  82
  83 static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie);
  84 static unsigned int      ip6_default_advmss(const struct dst_entry *dst);
  85 static unsigned int      ip6_mtu(const struct dst_entry *dst);
  86 static struct dst_entry *ip6_negative_advice(struct dst_entry *);
  87 static void             ip6_dst_destroy(struct dst_entry *);
  88 static void             ip6_dst_ifdown(struct dst_entry *,
  89                                        struct net_device *dev, int how);
  90 static int               ip6_dst_gc(struct dst_ops *ops);
  91
  92 static int              ip6_pkt_discard(struct sk_buff *skb);
  93 static int              ip6_pkt_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb);
  94 static int              ip6_pkt_prohibit(struct sk_buff *skb);
  95 static int              ip6_pkt_prohibit_out(struct net *net, struct sock *sk, struct sk_buff *skb);
  96 static void             ip6_link_failure(struct sk_buff *skb);
  97 static void             ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
  98                                            struct sk_buff *skb, u32 mtu,
  99                                            bool confirm_neigh);
 100 static void             rt6_do_redirect(struct dst_entry *dst, struct sock *sk,
 101                                         struct sk_buff *skb);
 102 static int rt6_score_route(const struct fib6_nh *nh, u32 fib6_flags, int oif,
 103                            int strict);
 104 static size_t rt6_nlmsg_size(struct fib6_info *f6i);
 105 static int rt6_fill_node(struct net *net, struct sk_buff *skb,
 106                          struct fib6_info *rt, struct dst_entry *dst,
 107                          struct in6_addr *dest, struct in6_addr *src,
 108                          int iif, int type, u32 portid, u32 seq,
 109                          unsigned int flags);
 110 static struct rt6_info *rt6_find_cached_rt(const struct fib6_result *res,
 111                                            const struct in6_addr *daddr,
 112                                            const struct in6_addr *saddr);
 113
 114 #ifdef CONFIG_IPV6_ROUTE_INFO
 115 static struct fib6_info *rt6_add_route_info(struct net *net,
 116                                            const struct in6_addr *prefix, int prefixlen,
 117                                            const struct in6_addr *gwaddr,
 118                                            struct net_device *dev,
 119                                            unsigned int pref);
 120 static struct fib6_info *rt6_get_route_info(struct net *net,
 121                                            const struct in6_addr *prefix, int prefixlen,
 122                                            const struct in6_addr *gwaddr,
 123                                            struct net_device *dev);
 124 #endif
 125
 126 struct uncached_list {
 127         spinlock_t              lock;
 128         struct list_head        head;
 129 };
 130
 131 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt6_uncached_list);
 132
 133 void rt6_uncached_list_add(struct rt6_info *rt)
 134 {
 135         struct uncached_list *ul = raw_cpu_ptr(&rt6_uncached_list);
 136
 137         rt->rt6i_uncached_list = ul;
 138
 139         spin_lock_bh(&ul->lock);
 140         list_add_tail(&rt->rt6i_uncached, &ul->head);
 141         spin_unlock_bh(&ul->lock);
 142 }
 143
 144 void rt6_uncached_list_del(struct rt6_info *rt)
 145 {
 146         if (!list_empty(&rt->rt6i_uncached)) {
 147                 struct uncached_list *ul = rt->rt6i_uncached_list;
 148                 struct net *net = dev_net(rt->dst.dev);
 149
 150                 spin_lock_bh(&ul->lock);
 151                 list_del(&rt->rt6i_uncached);
 152                 atomic_dec(&net->ipv6.rt6_stats->fib_rt_uncache);
 153                 spin_unlock_bh(&ul->lock);
 154         }
 155 }
 156
 157 static void rt6_uncached_list_flush_dev(struct net *net, struct net_device *dev)
 158 {
 159         struct net_device *loopback_dev = net->loopback_dev;
 160         int cpu;
 161
 162         if (dev == loopback_dev)
 163                 return;
 164
 165         for_each_possible_cpu(cpu) {
 166                 struct uncached_list *ul = per_cpu_ptr(&rt6_uncached_list, cpu);
 167                 struct rt6_info *rt;
 168
 169                 spin_lock_bh(&ul->lock);
 170                 list_for_each_entry(rt, &ul->head, rt6i_uncached) {
 171                         struct inet6_dev *rt_idev = rt->rt6i_idev;
 172                         struct net_device *rt_dev = rt->dst.dev;
 173
 174                         if (rt_idev->dev == dev) {
 175                                 rt->rt6i_idev = in6_dev_get(loopback_dev);
 176                                 in6_dev_put(rt_idev);
 177                         }
 178
 179                         if (rt_dev == dev) {
 180                                 rt->dst.dev = blackhole_netdev;
 181                                 dev_hold(rt->dst.dev);
 182                                 dev_put(rt_dev);
 183                         }
 184                 }
 185                 spin_unlock_bh(&ul->lock);
 186         }
 187 }
 188
 189 static inline const void *choose_neigh_daddr(const struct in6_addr *p,
 190                                              struct sk_buff *skb,
 191                                              const void *daddr)
 192 {
 193         if (!ipv6_addr_any(p))
 194                 return (const void *) p;
 195         else if (skb)
 196                 return &ipv6_hdr(skb)->daddr;
 197         return daddr;
 198 }
 199
 200 struct neighbour *ip6_neigh_lookup(const struct in6_addr *gw,
 201                                    struct net_device *dev,
 202                                    struct sk_buff *skb,
 203                                    const void *daddr)
 204 {
 205         struct neighbour *n;
 206
 207         daddr = choose_neigh_daddr(gw, skb, daddr);
 208         n = __ipv6_neigh_lookup(dev, daddr);
 209         if (n)
 210                 return n;
 211
 212         n = neigh_create(&nd_tbl, daddr, dev);
 213         return IS_ERR(n) ? NULL : n;
 214 }
 215
 216 static struct neighbour *ip6_dst_neigh_lookup(const struct dst_entry *dst,
 217                                               struct sk_buff *skb,
 218                                               const void *daddr)
 219 {
 220         const struct rt6_info *rt = container_of(dst, struct rt6_info, dst);
 221
 222         return ip6_neigh_lookup(rt6_nexthop(rt, &in6addr_any),
 223                                 dst->dev, skb, daddr);
 224 }
 225
 226 static void ip6_confirm_neigh(const struct dst_entry *dst, const void *daddr)
 227 {
 228         struct net_device *dev = dst->dev;
 229         struct rt6_info *rt = (struct rt6_info *)dst;
 230
 231         daddr = choose_neigh_daddr(rt6_nexthop(rt, &in6addr_any), NULL, daddr);
 232         if (!daddr)
 233                 return;
 234         if (dev->flags & (IFF_NOARP | IFF_LOOPBACK))
 235                 return;
 236         if (ipv6_addr_is_multicast((const struct in6_addr *)daddr))
 237                 return;
 238         __ipv6_confirm_neigh(dev, daddr);
 239 }
 240
 241 static struct dst_ops ip6_dst_ops_template = {
 242         .family                 =       AF_INET6,
 243         .gc                     =       ip6_dst_gc,
 244         .gc_thresh              =       1024,
 245         .check                  =       ip6_dst_check,
 246         .default_advmss         =       ip6_default_advmss,
 247         .mtu                    =       ip6_mtu,
 248         .cow_metrics            =       dst_cow_metrics_generic,
 249         .destroy                =       ip6_dst_destroy,
 250         .ifdown                 =       ip6_dst_ifdown,
 251         .negative_advice        =       ip6_negative_advice,
 252         .link_failure           =       ip6_link_failure,
 253         .update_pmtu            =       ip6_rt_update_pmtu,
 254         .redirect               =       rt6_do_redirect,
 255         .local_out              =       __ip6_local_out,
 256         .neigh_lookup           =       ip6_dst_neigh_lookup,
 257         .confirm_neigh          =       ip6_confirm_neigh,
 258 };
 259
 260 static unsigned int ip6_blackhole_mtu(const struct dst_entry *dst)
 261 {
 262         unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
 263
 264         return mtu ? : dst->dev->mtu;
 265 }
 266
 267 static void ip6_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
 268                                          struct sk_buff *skb, u32 mtu,
 269                                          bool confirm_neigh)
 270 {
 271 }
 272
 273 static void ip6_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
 274                                       struct sk_buff *skb)
 275 {
 276 }
 277
 278 static struct dst_ops ip6_dst_blackhole_ops = {
 279         .family                 =       AF_INET6,
 280         .destroy                =       ip6_dst_destroy,
 281         .check                  =       ip6_dst_check,
 282         .mtu                    =       ip6_blackhole_mtu,
 283         .default_advmss         =       ip6_default_advmss,
 284         .update_pmtu            =       ip6_rt_blackhole_update_pmtu,
 285         .redirect               =       ip6_rt_blackhole_redirect,
 286         .cow_metrics            =       dst_cow_metrics_generic,
 287         .neigh_lookup           =       ip6_dst_neigh_lookup,
 288 };
 289
 290 static const u32 ip6_template_metrics[RTAX_MAX] = {
 291         [RTAX_HOPLIMIT - 1] = 0,
 292 };
 293
 294 static const struct fib6_info fib6_null_entry_template = {
 295         .fib6_flags     = (RTF_REJECT | RTF_NONEXTHOP),
 296         .fib6_protocol  = RTPROT_KERNEL,
 297         .fib6_metric    = ~(u32)0,
 298         .fib6_ref       = REFCOUNT_INIT(1),
 299         .fib6_type      = RTN_UNREACHABLE,
 300         .fib6_metrics   = (struct dst_metrics *)&dst_default_metrics,
 301 };
 302
 303 static const struct rt6_info ip6_null_entry_template = {
 304         .dst = {
 305                 .__refcnt       = ATOMIC_INIT(1),
 306                 .__use          = 1,
 307                 .obsolete       = DST_OBSOLETE_FORCE_CHK,
 308                 .error          = -ENETUNREACH,
 309                 .input          = ip6_pkt_discard,
 310                 .output         = ip6_pkt_discard_out,
 311         },
 312         .rt6i_flags     = (RTF_REJECT | RTF_NONEXTHOP),
 313 };
 314
 315 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 316
 317 static const struct rt6_info ip6_prohibit_entry_template = {
 318         .dst = {
 319                 .__refcnt       = ATOMIC_INIT(1),
 320                 .__use          = 1,
 321                 .obsolete       = DST_OBSOLETE_FORCE_CHK,
 322                 .error          = -EACCES,
 323                 .input          = ip6_pkt_prohibit,
 324                 .output         = ip6_pkt_prohibit_out,
 325         },
 326         .rt6i_flags     = (RTF_REJECT | RTF_NONEXTHOP),
 327 };
 328
 329 static const struct rt6_info ip6_blk_hole_entry_template = {
 330         .dst = {
 331                 .__refcnt       = ATOMIC_INIT(1),
 332                 .__use          = 1,
 333                 .obsolete       = DST_OBSOLETE_FORCE_CHK,
 334                 .error          = -EINVAL,
 335                 .input          = dst_discard,
 336                 .output         = dst_discard_out,
 337         },
 338         .rt6i_flags     = (RTF_REJECT | RTF_NONEXTHOP),
 339 };
 340
 341 #endif
 342
 343 static void rt6_info_init(struct rt6_info *rt)
 344 {
 345         struct dst_entry *dst = &rt->dst;
 346
 347         memset(dst + 1, 0, sizeof(*rt) - sizeof(*dst));
 348         INIT_LIST_HEAD(&rt->rt6i_uncached);
 349 }
 350
 351 /* allocate dst with ip6_dst_ops */
 352 struct rt6_info *ip6_dst_alloc(struct net *net, struct net_device *dev,
 353                                int flags)
 354 {
 355         struct rt6_info *rt = dst_alloc(&net->ipv6.ip6_dst_ops, dev,
 356                                         1, DST_OBSOLETE_FORCE_CHK, flags);
 357
 358         if (rt) {
 359                 rt6_info_init(rt);
 360                 atomic_inc(&net->ipv6.rt6_stats->fib_rt_alloc);
 361         }
 362
 363         return rt;
 364 }
 365 EXPORT_SYMBOL(ip6_dst_alloc);
 366
 367 static void ip6_dst_destroy(struct dst_entry *dst)
 368 {
 369         struct rt6_info *rt = (struct rt6_info *)dst;
 370         struct fib6_info *from;
 371         struct inet6_dev *idev;
 372
 373         ip_dst_metrics_put(dst);
 374         rt6_uncached_list_del(rt);
 375
 376         idev = rt->rt6i_idev;
 377         if (idev) {
 378                 rt->rt6i_idev = NULL;
 379                 in6_dev_put(idev);
 380         }
 381
 382         from = xchg((__force struct fib6_info **)&rt->from, NULL);
 383         fib6_info_release(from);
 384 }
 385
 386 static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 387                            int how)
 388 {
 389         struct rt6_info *rt = (struct rt6_info *)dst;
 390         struct inet6_dev *idev = rt->rt6i_idev;
 391         struct net_device *loopback_dev =
 392                 dev_net(dev)->loopback_dev;
 393
 394         if (idev && idev->dev != loopback_dev) {
 395                 struct inet6_dev *loopback_idev = in6_dev_get(loopback_dev);
 396                 if (loopback_idev) {
 397                         rt->rt6i_idev = loopback_idev;
 398                         in6_dev_put(idev);
 399                 }
 400         }
 401 }
 402
 403 static bool __rt6_check_expired(const struct rt6_info *rt)
 404 {
 405         if (rt->rt6i_flags & RTF_EXPIRES)
 406                 return time_after(jiffies, rt->dst.expires);
 407         else
 408                 return false;
 409 }
 410
 411 static bool rt6_check_expired(const struct rt6_info *rt)
 412 {
 413         struct fib6_info *from;
 414
 415         from = rcu_dereference(rt->from);
 416
 417         if (rt->rt6i_flags & RTF_EXPIRES) {
 418                 if (time_after(jiffies, rt->dst.expires))
 419                         return true;
 420         } else if (from) {
 421                 return rt->dst.obsolete != DST_OBSOLETE_FORCE_CHK ||
 422                         fib6_check_expired(from);
 423         }
 424         return false;
 425 }
 426
 427 void fib6_select_path(const struct net *net, struct fib6_result *res,
 428                       struct flowi6 *fl6, int oif, bool have_oif_match,
 429                       const struct sk_buff *skb, int strict)
 430 {
 431         struct fib6_info *sibling, *next_sibling;
 432         struct fib6_info *match = res->f6i;
 433
 434         if ((!match->fib6_nsiblings && !match->nh) || have_oif_match)
 435                 goto out;
 436
 437         /* We might have already computed the hash for ICMPv6 errors. In such
 438          * case it will always be non-zero. Otherwise now is the time to do it.
 439          */
 440         if (!fl6->mp_hash &&
 441             (!match->nh || nexthop_is_multipath(match->nh)))
 442                 fl6->mp_hash = rt6_multipath_hash(net, fl6, skb, NULL);
 443
 444         if (unlikely(match->nh)) {
 445                 nexthop_path_fib6_result(res, fl6->mp_hash);
 446                 return;
 447         }
 448
 449         if (fl6->mp_hash <= atomic_read(&match->fib6_nh->fib_nh_upper_bound))
 450                 goto out;
 451
 452         list_for_each_entry_safe(sibling, next_sibling, &match->fib6_siblings,
 453                                  fib6_siblings) {
 454                 const struct fib6_nh *nh = sibling->fib6_nh;
 455                 int nh_upper_bound;
 456
 457                 nh_upper_bound = atomic_read(&nh->fib_nh_upper_bound);
 458                 if (fl6->mp_hash > nh_upper_bound)
 459                         continue;
 460                 if (rt6_score_route(nh, sibling->fib6_flags, oif, strict) < 0)
 461                         break;
 462                 match = sibling;
 463                 break;
 464         }
 465
 466 out:
 467         res->f6i = match;
 468         res->nh = match->fib6_nh;
 469 }
 470
 471 /*
 472  *      Route lookup. rcu_read_lock() should be held.
 473  */
 474
 475 static bool __rt6_device_match(struct net *net, const struct fib6_nh *nh,
 476                                const struct in6_addr *saddr, int oif, int flags)
 477 {
 478         const struct net_device *dev;
 479
 480         if (nh->fib_nh_flags & RTNH_F_DEAD)
 481                 return false;
 482
 483         dev = nh->fib_nh_dev;
 484         if (oif) {
 485                 if (dev->ifindex == oif)
 486                         return true;
 487         } else {
 488                 if (ipv6_chk_addr(net, saddr, dev,
 489                                   flags & RT6_LOOKUP_F_IFACE))
 490                         return true;
 491         }
 492
 493         return false;
 494 }
 495
 496 struct fib6_nh_dm_arg {
 497         struct net              *net;
 498         const struct in6_addr   *saddr;
 499         int                     oif;
 500         int                     flags;
 501         struct fib6_nh          *nh;
 502 };
 503
 504 static int __rt6_nh_dev_match(struct fib6_nh *nh, void *_arg)
 505 {
 506         struct fib6_nh_dm_arg *arg = _arg;
 507
 508         arg->nh = nh;
 509         return __rt6_device_match(arg->net, nh, arg->saddr, arg->oif,
 510                                   arg->flags);
 511 }
 512
 513 /* returns fib6_nh from nexthop or NULL */
 514 static struct fib6_nh *rt6_nh_dev_match(struct net *net, struct nexthop *nh,
 515                                         struct fib6_result *res,
 516                                         const struct in6_addr *saddr,
 517                                         int oif, int flags)
 518 {
 519         struct fib6_nh_dm_arg arg = {
 520                 .net   = net,
 521                 .saddr = saddr,
 522                 .oif   = oif,
 523                 .flags = flags,
 524         };
 525
 526         if (nexthop_is_blackhole(nh))
 527                 return NULL;
 528
 529         if (nexthop_for_each_fib6_nh(nh, __rt6_nh_dev_match, &arg))
 530                 return arg.nh;
 531
 532         return NULL;
 533 }
 534
 535 static void rt6_device_match(struct net *net, struct fib6_result *res,
 536                              const struct in6_addr *saddr, int oif, int flags)
 537 {
 538         struct fib6_info *f6i = res->f6i;
 539         struct fib6_info *spf6i;
 540         struct fib6_nh *nh;
 541
 542         if (!oif && ipv6_addr_any(saddr)) {
 543                 if (unlikely(f6i->nh)) {
 544                         nh = nexthop_fib6_nh(f6i->nh);
 545                         if (nexthop_is_blackhole(f6i->nh))
 546                                 goto out_blackhole;
 547                 } else {
 548                         nh = f6i->fib6_nh;
 549                 }
 550                 if (!(nh->fib_nh_flags & RTNH_F_DEAD))
 551                         goto out;
 552         }
 553
 554         for (spf6i = f6i; spf6i; spf6i = rcu_dereference(spf6i->fib6_next)) {
 555                 bool matched = false;
 556
 557                 if (unlikely(spf6i->nh)) {
 558                         nh = rt6_nh_dev_match(net, spf6i->nh, res, saddr,
 559                                               oif, flags);
 560                         if (nh)
 561                                 matched = true;
 562                 } else {
 563                         nh = spf6i->fib6_nh;
 564                         if (__rt6_device_match(net, nh, saddr, oif, flags))
 565                                 matched = true;
 566                 }
 567                 if (matched) {
 568                         res->f6i = spf6i;
 569                         goto out;
 570                 }
 571         }
 572
 573         if (oif && flags & RT6_LOOKUP_F_IFACE) {
 574                 res->f6i = net->ipv6.fib6_null_entry;
 575                 nh = res->f6i->fib6_nh;
 576                 goto out;
 577         }
 578
 579         if (unlikely(f6i->nh)) {
 580                 nh = nexthop_fib6_nh(f6i->nh);
 581                 if (nexthop_is_blackhole(f6i->nh))
 582                         goto out_blackhole;
 583         } else {
 584                 nh = f6i->fib6_nh;
 585         }
 586
 587         if (nh->fib_nh_flags & RTNH_F_DEAD) {
 588                 res->f6i = net->ipv6.fib6_null_entry;
 589                 nh = res->f6i->fib6_nh;
 590         }
 591 out:
 592         res->nh = nh;
 593         res->fib6_type = res->f6i->fib6_type;
 594         res->fib6_flags = res->f6i->fib6_flags;
 595         return;
 596
 597 out_blackhole:
 598         res->fib6_flags |= RTF_REJECT;
 599         res->fib6_type = RTN_BLACKHOLE;
 600         res->nh = nh;
 601 }
 602
 603 #ifdef CONFIG_IPV6_ROUTER_PREF
 604 struct __rt6_probe_work {
 605         struct work_struct work;
 606         struct in6_addr target;
 607         struct net_device *dev;
 608 };
 609
 610 static void rt6_probe_deferred(struct work_struct *w)
 611 {
 612         struct in6_addr mcaddr;
 613         struct __rt6_probe_work *work =
 614                 container_of(w, struct __rt6_probe_work, work);
 615
 616         addrconf_addr_solict_mult(&work->target, &mcaddr);
 617         ndisc_send_ns(work->dev, &work->target, &mcaddr, NULL, 0);
 618         dev_put(work->dev);
 619         kfree(work);
 620 }
 621
 622 static void rt6_probe(struct fib6_nh *fib6_nh)
 623 {
 624         struct __rt6_probe_work *work = NULL;
 625         const struct in6_addr *nh_gw;
 626         unsigned long last_probe;
 627         struct neighbour *neigh;
 628         struct net_device *dev;
 629         struct inet6_dev *idev;
 630
 631         /*
 632          * Okay, this does not seem to be appropriate
 633          * for now, however, we need to check if it
 634          * is really so; aka Router Reachability Probing.
 635          *
 636          * Router Reachability Probe MUST be rate-limited
 637          * to no more than one per minute.
 638          */
 639         if (!fib6_nh->fib_nh_gw_family)
 640                 return;
 641
 642         nh_gw = &fib6_nh->fib_nh_gw6;
 643         dev = fib6_nh->fib_nh_dev;
 644         rcu_read_lock_bh();
 645         last_probe = READ_ONCE(fib6_nh->last_probe);
 646         idev = __in6_dev_get(dev);
 647         neigh = __ipv6_neigh_lookup_noref(dev, nh_gw);
 648         if (neigh) {
 649                 if (neigh->nud_state & NUD_VALID)
 650                         goto out;
 651
 652                 write_lock(&neigh->lock);
 653                 if (!(neigh->nud_state & NUD_VALID) &&
 654                     time_after(jiffies,
 655                                neigh->updated + idev->cnf.rtr_probe_interval)) {
 656                         work = kmalloc(sizeof(*work), GFP_ATOMIC);
 657                         if (work)
 658                                 __neigh_set_probe_once(neigh);
 659                 }
 660                 write_unlock(&neigh->lock);
 661         } else if (time_after(jiffies, last_probe +
 662                                        idev->cnf.rtr_probe_interval)) {
 663                 work = kmalloc(sizeof(*work), GFP_ATOMIC);
 664         }
 665
 666         if (!work || cmpxchg(&fib6_nh->last_probe,
 667                              last_probe, jiffies) != last_probe) {
 668                 kfree(work);
 669         } else {
 670                 INIT_WORK(&work->work, rt6_probe_deferred);
 671                 work->target = *nh_gw;
 672                 dev_hold(dev);
 673                 work->dev = dev;
 674                 schedule_work(&work->work);
 675         }
 676
 677 out:
 678         rcu_read_unlock_bh();
 679 }
 680 #else
 681 static inline void rt6_probe(struct fib6_nh *fib6_nh)
 682 {
 683 }
 684 #endif
 685
 686 /*
 687  * Default Router Selection (RFC 2461 6.3.6)
 688  */
 689 static enum rt6_nud_state rt6_check_neigh(const struct fib6_nh *fib6_nh)
 690 {
 691         enum rt6_nud_state ret = RT6_NUD_FAIL_HARD;
 692         struct neighbour *neigh;
 693
 694         rcu_read_lock_bh();
 695         neigh = __ipv6_neigh_lookup_noref(fib6_nh->fib_nh_dev,
 696                                           &fib6_nh->fib_nh_gw6);
 697         if (neigh) {
 698                 read_lock(&neigh->lock);
 699                 if (neigh->nud_state & NUD_VALID)
 700                         ret = RT6_NUD_SUCCEED;
 701 #ifdef CONFIG_IPV6_ROUTER_PREF
 702                 else if (!(neigh->nud_state & NUD_FAILED))
 703                         ret = RT6_NUD_SUCCEED;
 704                 else
 705                         ret = RT6_NUD_FAIL_PROBE;
 706 #endif
 707                 read_unlock(&neigh->lock);
 708         } else {
 709                 ret = IS_ENABLED(CONFIG_IPV6_ROUTER_PREF) ?
 710                       RT6_NUD_SUCCEED : RT6_NUD_FAIL_DO_RR;
 711         }
 712         rcu_read_unlock_bh();
 713
 714         return ret;
 715 }
 716
 717 static int rt6_score_route(const struct fib6_nh *nh, u32 fib6_flags, int oif,
 718                            int strict)
 719 {
 720         int m = 0;
 721
 722         if (!oif || nh->fib_nh_dev->ifindex == oif)
 723                 m = 2;
 724
 725         if (!m && (strict & RT6_LOOKUP_F_IFACE))
 726                 return RT6_NUD_FAIL_HARD;
 727 #ifdef CONFIG_IPV6_ROUTER_PREF
 728         m |= IPV6_DECODE_PREF(IPV6_EXTRACT_PREF(fib6_flags)) << 2;
 729 #endif
 730         if ((strict & RT6_LOOKUP_F_REACHABLE) &&
 731             !(fib6_flags & RTF_NONEXTHOP) && nh->fib_nh_gw_family) {
 732                 int n = rt6_check_neigh(nh);
 733                 if (n < 0)
 734                         return n;
 735         }
 736         return m;
 737 }
 738
 739 static bool find_match(struct fib6_nh *nh, u32 fib6_flags,
 740                        int oif, int strict, int *mpri, bool *do_rr)
 741 {
 742         bool match_do_rr = false;
 743         bool rc = false;
 744         int m;
 745
 746         if (nh->fib_nh_flags & RTNH_F_DEAD)
 747                 goto out;
 748
 749         if (ip6_ignore_linkdown(nh->fib_nh_dev) &&
 750             nh->fib_nh_flags & RTNH_F_LINKDOWN &&
 751             !(strict & RT6_LOOKUP_F_IGNORE_LINKSTATE))
 752                 goto out;
 753
 754         m = rt6_score_route(nh, fib6_flags, oif, strict);
 755         if (m == RT6_NUD_FAIL_DO_RR) {
 756                 match_do_rr = true;
 757                 m = 0; /* lowest valid score */
 758         } else if (m == RT6_NUD_FAIL_HARD) {
 759                 goto out;
 760         }
 761
 762         if (strict & RT6_LOOKUP_F_REACHABLE)
 763                 rt6_probe(nh);
 764
 765         /* note that m can be RT6_NUD_FAIL_PROBE at this point */
 766         if (m > *mpri) {
 767                 *do_rr = match_do_rr;
 768                 *mpri = m;
 769                 rc = true;
 770         }
 771 out:
 772         return rc;
 773 }
 774
 775 struct fib6_nh_frl_arg {
 776         u32             flags;
 777         int             oif;
 778         int             strict;
 779         int             *mpri;
 780         bool            *do_rr;
 781         struct fib6_nh  *nh;
 782 };
 783
 784 static int rt6_nh_find_match(struct fib6_nh *nh, void *_arg)
 785 {
 786         struct fib6_nh_frl_arg *arg = _arg;
 787
 788         arg->nh = nh;
 789         return find_match(nh, arg->flags, arg->oif, arg->strict,
 790                           arg->mpri, arg->do_rr);
 791 }
 792
 793 static void __find_rr_leaf(struct fib6_info *f6i_start,
 794                            struct fib6_info *nomatch, u32 metric,
 795                            struct fib6_result *res, struct fib6_info **cont,
 796                            int oif, int strict, bool *do_rr, int *mpri)
 797 {
 798         struct fib6_info *f6i;
 799
 800         for (f6i = f6i_start;
 801              f6i && f6i != nomatch;
 802              f6i = rcu_dereference(f6i->fib6_next)) {
 803                 bool matched = false;
 804                 struct fib6_nh *nh;
 805
 806                 if (cont && f6i->fib6_metric != metric) {
 807                         *cont = f6i;
 808                         return;
 809                 }
 810
 811                 if (fib6_check_expired(f6i))
 812                         continue;
 813
 814                 if (unlikely(f6i->nh)) {
 815                         struct fib6_nh_frl_arg arg = {
 816                                 .flags  = f6i->fib6_flags,
 817                                 .oif    = oif,
 818                                 .strict = strict,
 819                                 .mpri   = mpri,
 820                                 .do_rr  = do_rr
 821                         };
 822
 823                         if (nexthop_is_blackhole(f6i->nh)) {
 824                                 res->fib6_flags = RTF_REJECT;
 825                                 res->fib6_type = RTN_BLACKHOLE;
 826                                 res->f6i = f6i;
 827                                 res->nh = nexthop_fib6_nh(f6i->nh);
 828                                 return;
 829                         }
 830                         if (nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_find_match,
 831                                                      &arg)) {
 832                                 matched = true;
 833                                 nh = arg.nh;
 834                         }
 835                 } else {
 836                         nh = f6i->fib6_nh;
 837                         if (find_match(nh, f6i->fib6_flags, oif, strict,
 838                                        mpri, do_rr))
 839                                 matched = true;
 840                 }
 841                 if (matched) {
 842                         res->f6i = f6i;
 843                         res->nh = nh;
 844                         res->fib6_flags = f6i->fib6_flags;
 845                         res->fib6_type = f6i->fib6_type;
 846                 }
 847         }
 848 }
 849
 850 static void find_rr_leaf(struct fib6_node *fn, struct fib6_info *leaf,
 851                          struct fib6_info *rr_head, int oif, int strict,
 852                          bool *do_rr, struct fib6_result *res)
 853 {
 854         u32 metric = rr_head->fib6_metric;
 855         struct fib6_info *cont = NULL;
 856         int mpri = -1;
 857
 858         __find_rr_leaf(rr_head, NULL, metric, res, &cont,
 859                        oif, strict, do_rr, &mpri);
 860
 861         __find_rr_leaf(leaf, rr_head, metric, res, &cont,
 862                        oif, strict, do_rr, &mpri);
 863
 864         if (res->f6i || !cont)
 865                 return;
 866
 867         __find_rr_leaf(cont, NULL, metric, res, NULL,
 868                        oif, strict, do_rr, &mpri);
 869 }
 870
 871 static void rt6_select(struct net *net, struct fib6_node *fn, int oif,
 872                        struct fib6_result *res, int strict)
 873 {
 874         struct fib6_info *leaf = rcu_dereference(fn->leaf);
 875         struct fib6_info *rt0;
 876         bool do_rr = false;
 877         int key_plen;
 878
 879         /* make sure this function or its helpers sets f6i */
 880         res->f6i = NULL;
 881
 882         if (!leaf || leaf == net->ipv6.fib6_null_entry)
 883                 goto out;
 884
 885         rt0 = rcu_dereference(fn->rr_ptr);
 886         if (!rt0)
 887                 rt0 = leaf;
 888
 889         /* Double check to make sure fn is not an intermediate node
 890          * and fn->leaf does not points to its child's leaf
 891          * (This might happen if all routes under fn are deleted from
 892          * the tree and fib6_repair_tree() is called on the node.)
 893          */
 894         key_plen = rt0->fib6_dst.plen;
 895 #ifdef CONFIG_IPV6_SUBTREES
 896         if (rt0->fib6_src.plen)
 897                 key_plen = rt0->fib6_src.plen;
 898 #endif
 899         if (fn->fn_bit != key_plen)
 900                 goto out;
 901
 902         find_rr_leaf(fn, leaf, rt0, oif, strict, &do_rr, res);
 903         if (do_rr) {
 904                 struct fib6_info *next = rcu_dereference(rt0->fib6_next);
 905
 906                 /* no entries matched; do round-robin */
 907                 if (!next || next->fib6_metric != rt0->fib6_metric)
 908                         next = leaf;
 909
 910                 if (next != rt0) {
 911                         spin_lock_bh(&leaf->fib6_table->tb6_lock);
 912                         /* make sure next is not being deleted from the tree */
 913                         if (next->fib6_node)
 914                                 rcu_assign_pointer(fn->rr_ptr, next);
 915                         spin_unlock_bh(&leaf->fib6_table->tb6_lock);
 916                 }
 917         }
 918
 919 out:
 920         if (!res->f6i) {
 921                 res->f6i = net->ipv6.fib6_null_entry;
 922                 res->nh = res->f6i->fib6_nh;
 923                 res->fib6_flags = res->f6i->fib6_flags;
 924                 res->fib6_type = res->f6i->fib6_type;
 925         }
 926 }
 927
 928 static bool rt6_is_gw_or_nonexthop(const struct fib6_result *res)
 929 {
 930         return (res->f6i->fib6_flags & RTF_NONEXTHOP) ||
 931                res->nh->fib_nh_gw_family;
 932 }
 933
 934 #ifdef CONFIG_IPV6_ROUTE_INFO
 935 int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
 936                   const struct in6_addr *gwaddr)
 937 {
 938         struct net *net = dev_net(dev);
 939         struct route_info *rinfo = (struct route_info *) opt;
 940         struct in6_addr prefix_buf, *prefix;
 941         unsigned int pref;
 942         unsigned long lifetime;
 943         struct fib6_info *rt;
 944
 945         if (len < sizeof(struct route_info)) {
 946                 return -EINVAL;
 947         }
 948
 949         /* Sanity check for prefix_len and length */
 950         if (rinfo->length > 3) {
 951                 return -EINVAL;
 952         } else if (rinfo->prefix_len > 128) {
 953                 return -EINVAL;
 954         } else if (rinfo->prefix_len > 64) {
 955                 if (rinfo->length < 2) {
 956                         return -EINVAL;
 957                 }
 958         } else if (rinfo->prefix_len > 0) {
 959                 if (rinfo->length < 1) {
 960                         return -EINVAL;
 961                 }
 962         }
 963
 964         pref = rinfo->route_pref;
 965         if (pref == ICMPV6_ROUTER_PREF_INVALID)
 966                 return -EINVAL;
 967
 968         lifetime = addrconf_timeout_fixup(ntohl(rinfo->lifetime), HZ);
 969
 970         if (rinfo->length == 3)
 971                 prefix = (struct in6_addr *)rinfo->prefix;
 972         else {
 973                 /* this function is safe */
 974                 ipv6_addr_prefix(&prefix_buf,
 975                                  (struct in6_addr *)rinfo->prefix,
 976                                  rinfo->prefix_len);
 977                 prefix = &prefix_buf;
 978         }
 979
 980         if (rinfo->prefix_len == 0)
 981                 rt = rt6_get_dflt_router(net, gwaddr, dev);
 982         else
 983                 rt = rt6_get_route_info(net, prefix, rinfo->prefix_len,
 984                                         gwaddr, dev);
 985
 986         if (rt && !lifetime) {
 987                 ip6_del_rt(net, rt, false);
 988                 rt = NULL;
 989         }
 990
 991         if (!rt && lifetime)
 992                 rt = rt6_add_route_info(net, prefix, rinfo->prefix_len, gwaddr,
 993                                         dev, pref);
 994         else if (rt)
 995                 rt->fib6_flags = RTF_ROUTEINFO |
 996                                  (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
 997
 998         if (rt) {
 999                 if (!addrconf_finite_timeout(lifetime))
1000                         fib6_clean_expires(rt);
1001                 else
1002                         fib6_set_expires(rt, jiffies + HZ * lifetime);
1003
1004                 fib6_info_release(rt);
1005         }
1006         return 0;
1007 }
1008 #endif
1009
1010 /*
1011  *      Misc support functions
1012  */
1013
1014 /* called with rcu_lock held */
1015 static struct net_device *ip6_rt_get_dev_rcu(const struct fib6_result *res)
1016 {
1017         struct net_device *dev = res->nh->fib_nh_dev;
1018
1019         if (res->fib6_flags & (RTF_LOCAL | RTF_ANYCAST)) {
1020                 /* for copies of local routes, dst->dev needs to be the
1021                  * device if it is a master device, the master device if
1022                  * device is enslaved, and the loopback as the default
1023                  */
1024                 if (netif_is_l3_slave(dev) &&
1025                     !rt6_need_strict(&res->f6i->fib6_dst.addr))
1026                         dev = l3mdev_master_dev_rcu(dev);
1027                 else if (!netif_is_l3_master(dev))
1028                         dev = dev_net(dev)->loopback_dev;
1029                 /* last case is netif_is_l3_master(dev) is true in which
1030                  * case we want dev returned to be dev
1031                  */
1032         }
1033
1034         return dev;
1035 }
1036
1037 static const int fib6_prop[RTN_MAX + 1] = {
1038         [RTN_UNSPEC]    = 0,
1039         [RTN_UNICAST]   = 0,
1040         [RTN_LOCAL]     = 0,
1041         [RTN_BROADCAST] = 0,
1042         [RTN_ANYCAST]   = 0,
1043         [RTN_MULTICAST] = 0,
1044         [RTN_BLACKHOLE] = -EINVAL,
1045         [RTN_UNREACHABLE] = -EHOSTUNREACH,
1046         [RTN_PROHIBIT]  = -EACCES,
1047         [RTN_THROW]     = -EAGAIN,
1048         [RTN_NAT]       = -EINVAL,
1049         [RTN_XRESOLVE]  = -EINVAL,
1050 };
1051
1052 static int ip6_rt_type_to_error(u8 fib6_type)
1053 {
1054         return fib6_prop[fib6_type];
1055 }
1056
1057 static unsigned short fib6_info_dst_flags(struct fib6_info *rt)
1058 {
1059         unsigned short flags = 0;
1060
1061         if (rt->dst_nocount)
1062                 flags |= DST_NOCOUNT;
1063         if (rt->dst_nopolicy)
1064                 flags |= DST_NOPOLICY;
1065
1066         return flags;
1067 }
1068
1069 static void ip6_rt_init_dst_reject(struct rt6_info *rt, u8 fib6_type)
1070 {
1071         rt->dst.error = ip6_rt_type_to_error(fib6_type);
1072
1073         switch (fib6_type) {
1074         case RTN_BLACKHOLE:
1075                 rt->dst.output = dst_discard_out;
1076                 rt->dst.input = dst_discard;
1077                 break;
1078         case RTN_PROHIBIT:
1079                 rt->dst.output = ip6_pkt_prohibit_out;
1080                 rt->dst.input = ip6_pkt_prohibit;
1081                 break;
1082         case RTN_THROW:
1083         case RTN_UNREACHABLE:
1084         default:
1085                 rt->dst.output = ip6_pkt_discard_out;
1086                 rt->dst.input = ip6_pkt_discard;
1087                 break;
1088         }
1089 }
1090
1091 static void ip6_rt_init_dst(struct rt6_info *rt, const struct fib6_result *res)
1092 {
1093         struct fib6_info *f6i = res->f6i;
1094
1095         if (res->fib6_flags & RTF_REJECT) {
1096                 ip6_rt_init_dst_reject(rt, res->fib6_type);
1097                 return;
1098         }
1099
1100         rt->dst.error = 0;
1101         rt->dst.output = ip6_output;
1102
1103         if (res->fib6_type == RTN_LOCAL || res->fib6_type == RTN_ANYCAST) {
1104                 rt->dst.input = ip6_input;
1105         } else if (ipv6_addr_type(&f6i->fib6_dst.addr) & IPV6_ADDR_MULTICAST) {
1106                 rt->dst.input = ip6_mc_input;
1107         } else {
1108                 rt->dst.input = ip6_forward;
1109         }
1110
1111         if (res->nh->fib_nh_lws) {
1112                 rt->dst.lwtstate = lwtstate_get(res->nh->fib_nh_lws);
1113                 lwtunnel_set_redirect(&rt->dst);
1114         }
1115
1116         rt->dst.lastuse = jiffies;
1117 }
1118
1119 /* Caller must already hold reference to @from */
1120 static void rt6_set_from(struct rt6_info *rt, struct fib6_info *from)
1121 {
1122         rt->rt6i_flags &= ~RTF_EXPIRES;
1123         rcu_assign_pointer(rt->from, from);
1124         ip_dst_init_metrics(&rt->dst, from->fib6_metrics);
1125 }
1126
1127 /* Caller must already hold reference to f6i in result */
1128 static void ip6_rt_copy_init(struct rt6_info *rt, const struct fib6_result *res)
1129 {
1130         const struct fib6_nh *nh = res->nh;
1131         const struct net_device *dev = nh->fib_nh_dev;
1132         struct fib6_info *f6i = res->f6i;
1133
1134         ip6_rt_init_dst(rt, res);
1135
1136         rt->rt6i_dst = f6i->fib6_dst;
1137         rt->rt6i_idev = dev ? in6_dev_get(dev) : NULL;
1138         rt->rt6i_flags = res->fib6_flags;
1139         if (nh->fib_nh_gw_family) {
1140                 rt->rt6i_gateway = nh->fib_nh_gw6;
1141                 rt->rt6i_flags |= RTF_GATEWAY;
1142         }
1143         rt6_set_from(rt, f6i);
1144 #ifdef CONFIG_IPV6_SUBTREES
1145         rt->rt6i_src = f6i->fib6_src;
1146 #endif
1147 }
1148
1149 static struct fib6_node* fib6_backtrack(struct fib6_node *fn,
1150                                         struct in6_addr *saddr)
1151 {
1152         struct fib6_node *pn, *sn;
1153         while (1) {
1154                 if (fn->fn_flags & RTN_TL_ROOT)
1155                         return NULL;
1156                 pn = rcu_dereference(fn->parent);
1157                 sn = FIB6_SUBTREE(pn);
1158                 if (sn && sn != fn)
1159                         fn = fib6_node_lookup(sn, NULL, saddr);
1160                 else
1161                         fn = pn;
1162                 if (fn->fn_flags & RTN_RTINFO)
1163                         return fn;
1164         }
1165 }
1166
1167 static bool ip6_hold_safe(struct net *net, struct rt6_info **prt)
1168 {
1169         struct rt6_info *rt = *prt;
1170
1171         if (dst_hold_safe(&rt->dst))
1172                 return true;
1173         if (net) {
1174                 rt = net->ipv6.ip6_null_entry;
1175                 dst_hold(&rt->dst);
1176         } else {
1177                 rt = NULL;
1178         }
1179         *prt = rt;
1180         return false;
1181 }
1182
1183 /* called with rcu_lock held */
1184 static struct rt6_info *ip6_create_rt_rcu(const struct fib6_result *res)
1185 {
1186         struct net_device *dev = res->nh->fib_nh_dev;
1187         struct fib6_info *f6i = res->f6i;
1188         unsigned short flags;
1189         struct rt6_info *nrt;
1190
1191         if (!fib6_info_hold_safe(f6i))
1192                 goto fallback;
1193
1194         flags = fib6_info_dst_flags(f6i);
1195         nrt = ip6_dst_alloc(dev_net(dev), dev, flags);
1196         if (!nrt) {
1197                 fib6_info_release(f6i);
1198                 goto fallback;
1199         }
1200
1201         ip6_rt_copy_init(nrt, res);
1202         return nrt;
1203
1204 fallback:
1205         nrt = dev_net(dev)->ipv6.ip6_null_entry;
1206         dst_hold(&nrt->dst);
1207         return nrt;
1208 }
1209
1210 static struct rt6_info *ip6_pol_route_lookup(struct net *net,
1211                                              struct fib6_table *table,
1212                                              struct flowi6 *fl6,
1213                                              const struct sk_buff *skb,
1214                                              int flags)
1215 {
1216         struct fib6_result res = {};
1217         struct fib6_node *fn;
1218         struct rt6_info *rt;
1219
1220         if (fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF)
1221                 flags &= ~RT6_LOOKUP_F_IFACE;
1222
1223         rcu_read_lock();
1224         fn = fib6_node_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
1225 restart:
1226         res.f6i = rcu_dereference(fn->leaf);
1227         if (!res.f6i)
1228                 res.f6i = net->ipv6.fib6_null_entry;
1229         else
1230                 rt6_device_match(net, &res, &fl6->saddr, fl6->flowi6_oif,
1231                                  flags);
1232
1233         if (res.f6i == net->ipv6.fib6_null_entry) {
1234                 fn = fib6_backtrack(fn, &fl6->saddr);
1235                 if (fn)
1236                         goto restart;
1237
1238                 rt = net->ipv6.ip6_null_entry;
1239                 dst_hold(&rt->dst);
1240                 goto out;
1241         } else if (res.fib6_flags & RTF_REJECT) {
1242                 goto do_create;
1243         }
1244
1245         fib6_select_path(net, &res, fl6, fl6->flowi6_oif,
1246                          fl6->flowi6_oif != 0, skb, flags);
1247
1248         /* Search through exception table */
1249         rt = rt6_find_cached_rt(&res, &fl6->daddr, &fl6->saddr);
1250         if (rt) {
1251                 if (ip6_hold_safe(net, &rt))
1252                         dst_use_noref(&rt->dst, jiffies);
1253         } else {
1254 do_create:
1255                 rt = ip6_create_rt_rcu(&res);
1256         }
1257
1258 out:
1259         trace_fib6_table_lookup(net, &res, table, fl6);
1260
1261         rcu_read_unlock();
1262
1263         return rt;
1264 }
1265
1266 struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6,
1267                                    const struct sk_buff *skb, int flags)
1268 {
1269         return fib6_rule_lookup(net, fl6, skb, flags, ip6_pol_route_lookup);
1270 }
1271 EXPORT_SYMBOL_GPL(ip6_route_lookup);
1272
1273 struct rt6_info *rt6_lookup(struct net *net, const struct in6_addr *daddr,
1274                             const struct in6_addr *saddr, int oif,
1275                             const struct sk_buff *skb, int strict)
1276 {
1277         struct flowi6 fl6 = {
1278                 .flowi6_oif = oif,
1279                 .daddr = *daddr,
1280         };
1281         struct dst_entry *dst;
1282         int flags = strict ? RT6_LOOKUP_F_IFACE : 0;
1283
1284         if (saddr) {
1285                 memcpy(&fl6.saddr, saddr, sizeof(*saddr));
1286                 flags |= RT6_LOOKUP_F_HAS_SADDR;
1287         }
1288
1289         dst = fib6_rule_lookup(net, &fl6, skb, flags, ip6_pol_route_lookup);
1290         if (dst->error == 0)
1291                 return (struct rt6_info *) dst;
1292
1293         dst_release(dst);
1294
1295         return NULL;
1296 }
1297 EXPORT_SYMBOL(rt6_lookup);
1298
1299 /* ip6_ins_rt is called with FREE table->tb6_lock.
1300  * It takes new route entry, the addition fails by any reason the
1301  * route is released.
1302  * Caller must hold dst before calling it.
1303  */
1304
1305 static int __ip6_ins_rt(struct fib6_info *rt, struct nl_info *info,
1306                         struct netlink_ext_ack *extack)
1307 {
1308         int err;
1309         struct fib6_table *table;
1310
1311         table = rt->fib6_table;
1312         spin_lock_bh(&table->tb6_lock);
1313         err = fib6_add(&table->tb6_root, rt, info, extack);
1314         spin_unlock_bh(&table->tb6_lock);
1315
1316         return err;
1317 }
1318
1319 int ip6_ins_rt(struct net *net, struct fib6_info *rt)
1320 {
1321         struct nl_info info = { .nl_net = net, };
1322
1323         return __ip6_ins_rt(rt, &info, NULL);
1324 }
1325
1326 static struct rt6_info *ip6_rt_cache_alloc(const struct fib6_result *res,
1327                                            const struct in6_addr *daddr,
1328                                            const struct in6_addr *saddr)
1329 {
1330         struct fib6_info *f6i = res->f6i;
1331         struct net_device *dev;
1332         struct rt6_info *rt;
1333
1334         /*
1335          *      Clone the route.
1336          */
1337
1338         if (!fib6_info_hold_safe(f6i))
1339                 return NULL;
1340
1341         dev = ip6_rt_get_dev_rcu(res);
1342         rt = ip6_dst_alloc(dev_net(dev), dev, 0);
1343         if (!rt) {
1344                 fib6_info_release(f6i);
1345                 return NULL;
1346         }
1347
1348         ip6_rt_copy_init(rt, res);
1349         rt->rt6i_flags |= RTF_CACHE;
1350         rt->rt6i_dst.addr = *daddr;
1351         rt->rt6i_dst.plen = 128;
1352
1353         if (!rt6_is_gw_or_nonexthop(res)) {
1354                 if (f6i->fib6_dst.plen != 128 &&
1355                     ipv6_addr_equal(&f6i->fib6_dst.addr, daddr))
1356                         rt->rt6i_flags |= RTF_ANYCAST;
1357 #ifdef CONFIG_IPV6_SUBTREES
1358                 if (rt->rt6i_src.plen && saddr) {
1359                         rt->rt6i_src.addr = *saddr;
1360                         rt->rt6i_src.plen = 128;
1361                 }
1362 #endif
1363         }
1364
1365         return rt;
1366 }
1367
1368 static struct rt6_info *ip6_rt_pcpu_alloc(const struct fib6_result *res)
1369 {
1370         struct fib6_info *f6i = res->f6i;
1371         unsigned short flags = fib6_info_dst_flags(f6i);
1372         struct net_device *dev;
1373         struct rt6_info *pcpu_rt;
1374
1375         if (!fib6_info_hold_safe(f6i))
1376                 return NULL;
1377
1378         rcu_read_lock();
1379         dev = ip6_rt_get_dev_rcu(res);
1380         pcpu_rt = ip6_dst_alloc(dev_net(dev), dev, flags);
1381         rcu_read_unlock();
1382         if (!pcpu_rt) {
1383                 fib6_info_release(f6i);
1384                 return NULL;
1385         }
1386         ip6_rt_copy_init(pcpu_rt, res);
1387         pcpu_rt->rt6i_flags |= RTF_PCPU;
1388         return pcpu_rt;
1389 }
1390
1391 /* It should be called with rcu_read_lock() acquired */
1392 static struct rt6_info *rt6_get_pcpu_route(const struct fib6_result *res)
1393 {
1394         struct rt6_info *pcpu_rt;
1395
1396         pcpu_rt = this_cpu_read(*res->nh->rt6i_pcpu);
1397
1398         return pcpu_rt;
1399 }
1400
1401 static struct rt6_info *rt6_make_pcpu_route(struct net *net,
1402                                             const struct fib6_result *res)
1403 {
1404         struct rt6_info *pcpu_rt, *prev, **p;
1405
1406         pcpu_rt = ip6_rt_pcpu_alloc(res);
1407         if (!pcpu_rt)
1408                 return NULL;
1409
1410         p = this_cpu_ptr(res->nh->rt6i_pcpu);
1411         prev = cmpxchg(p, NULL, pcpu_rt);
1412         BUG_ON(prev);
1413
1414         if (res->f6i->fib6_destroying) {
1415                 struct fib6_info *from;
1416
1417                 from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
1418                 fib6_info_release(from);
1419         }
1420
1421         return pcpu_rt;
1422 }
1423
1424 /* exception hash table implementation
1425  */
1426 static DEFINE_SPINLOCK(rt6_exception_lock);
1427
1428 /* Remove rt6_ex from hash table and free the memory
1429  * Caller must hold rt6_exception_lock
1430  */
1431 static void rt6_remove_exception(struct rt6_exception_bucket *bucket,
1432                                  struct rt6_exception *rt6_ex)
1433 {
1434         struct fib6_info *from;
1435         struct net *net;
1436
1437         if (!bucket || !rt6_ex)
1438                 return;
1439
1440         net = dev_net(rt6_ex->rt6i->dst.dev);
1441         net->ipv6.rt6_stats->fib_rt_cache--;
1442
1443         /* purge completely the exception to allow releasing the held resources:
1444          * some [sk] cache may keep the dst around for unlimited time
1445          */
1446         from = xchg((__force struct fib6_info **)&rt6_ex->rt6i->from, NULL);
1447         fib6_info_release(from);
1448         dst_dev_put(&rt6_ex->rt6i->dst);
1449
1450         hlist_del_rcu(&rt6_ex->hlist);
1451         dst_release(&rt6_ex->rt6i->dst);
1452         kfree_rcu(rt6_ex, rcu);
1453         WARN_ON_ONCE(!bucket->depth);
1454         bucket->depth--;
1455 }
1456
1457 /* Remove oldest rt6_ex in bucket and free the memory
1458  * Caller must hold rt6_exception_lock
1459  */
1460 static void rt6_exception_remove_oldest(struct rt6_exception_bucket *bucket)
1461 {
1462         struct rt6_exception *rt6_ex, *oldest = NULL;
1463
1464         if (!bucket)
1465                 return;
1466
1467         hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
1468                 if (!oldest || time_before(rt6_ex->stamp, oldest->stamp))
1469                         oldest = rt6_ex;
1470         }
1471         rt6_remove_exception(bucket, oldest);
1472 }
1473
1474 static u32 rt6_exception_hash(const struct in6_addr *dst,
1475                               const struct in6_addr *src)
1476 {
1477         static u32 seed __read_mostly;
1478         u32 val;
1479
1480         net_get_random_once(&seed, sizeof(seed));
1481         val = jhash2((const u32 *)dst, sizeof(*dst)/sizeof(u32), seed);
1482
1483 #ifdef CONFIG_IPV6_SUBTREES
1484         if (src)
1485                 val = jhash2((const u32 *)src, sizeof(*src)/sizeof(u32), val);
1486 #endif
1487         return hash_32(val, FIB6_EXCEPTION_BUCKET_SIZE_SHIFT);
1488 }
1489
1490 /* Helper function to find the cached rt in the hash table
1491  * and update bucket pointer to point to the bucket for this
1492  * (daddr, saddr) pair
1493  * Caller must hold rt6_exception_lock
1494  */
1495 static struct rt6_exception *
1496 __rt6_find_exception_spinlock(struct rt6_exception_bucket **bucket,
1497                               const struct in6_addr *daddr,
1498                               const struct in6_addr *saddr)
1499 {
1500         struct rt6_exception *rt6_ex;
1501         u32 hval;
1502
1503         if (!(*bucket) || !daddr)
1504                 return NULL;
1505
1506         hval = rt6_exception_hash(daddr, saddr);
1507         *bucket += hval;
1508
1509         hlist_for_each_entry(rt6_ex, &(*bucket)->chain, hlist) {
1510                 struct rt6_info *rt6 = rt6_ex->rt6i;
1511                 bool matched = ipv6_addr_equal(daddr, &rt6->rt6i_dst.addr);
1512
1513 #ifdef CONFIG_IPV6_SUBTREES
1514                 if (matched && saddr)
1515                         matched = ipv6_addr_equal(saddr, &rt6->rt6i_src.addr);
1516 #endif
1517                 if (matched)
1518                         return rt6_ex;
1519         }
1520         return NULL;
1521 }
1522
1523 /* Helper function to find the cached rt in the hash table
1524  * and update bucket pointer to point to the bucket for this
1525  * (daddr, saddr) pair
1526  * Caller must hold rcu_read_lock()
1527  */
1528 static struct rt6_exception *
1529 __rt6_find_exception_rcu(struct rt6_exception_bucket **bucket,
1530                          const struct in6_addr *daddr,
1531                          const struct in6_addr *saddr)
1532 {
1533         struct rt6_exception *rt6_ex;
1534         u32 hval;
1535
1536         WARN_ON_ONCE(!rcu_read_lock_held());
1537
1538         if (!(*bucket) || !daddr)
1539                 return NULL;
1540
1541         hval = rt6_exception_hash(daddr, saddr);
1542         *bucket += hval;
1543
1544         hlist_for_each_entry_rcu(rt6_ex, &(*bucket)->chain, hlist) {
1545                 struct rt6_info *rt6 = rt6_ex->rt6i;
1546                 bool matched = ipv6_addr_equal(daddr, &rt6->rt6i_dst.addr);
1547
1548 #ifdef CONFIG_IPV6_SUBTREES
1549                 if (matched && saddr)
1550                         matched = ipv6_addr_equal(saddr, &rt6->rt6i_src.addr);
1551 #endif
1552                 if (matched)
1553                         return rt6_ex;
1554         }
1555         return NULL;
1556 }
1557
1558 static unsigned int fib6_mtu(const struct fib6_result *res)
1559 {
1560         const struct fib6_nh *nh = res->nh;
1561         unsigned int mtu;
1562
1563         if (res->f6i->fib6_pmtu) {
1564                 mtu = res->f6i->fib6_pmtu;
1565         } else {
1566                 struct net_device *dev = nh->fib_nh_dev;
1567                 struct inet6_dev *idev;
1568
1569                 rcu_read_lock();
1570                 idev = __in6_dev_get(dev);
1571                 mtu = idev->cnf.mtu6;
1572                 rcu_read_unlock();
1573         }
1574
1575         mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);
1576
1577         return mtu - lwtunnel_headroom(nh->fib_nh_lws, mtu);
1578 }
1579
1580 #define FIB6_EXCEPTION_BUCKET_FLUSHED  0x1UL
1581
1582 /* used when the flushed bit is not relevant, only access to the bucket
1583  * (ie., all bucket users except rt6_insert_exception);
1584  *
1585  * called under rcu lock; sometimes called with rt6_exception_lock held
1586  */
1587 static
1588 struct rt6_exception_bucket *fib6_nh_get_excptn_bucket(const struct fib6_nh *nh,
1589                                                        spinlock_t *lock)
1590 {
1591         struct rt6_exception_bucket *bucket;
1592
1593         if (lock)
1594                 bucket = rcu_dereference_protected(nh->rt6i_exception_bucket,
1595                                                    lockdep_is_held(lock));
1596         else
1597                 bucket = rcu_dereference(nh->rt6i_exception_bucket);
1598
1599         /* remove bucket flushed bit if set */
1600         if (bucket) {
1601                 unsigned long p = (unsigned long)bucket;
1602
1603                 p &= ~FIB6_EXCEPTION_BUCKET_FLUSHED;
1604                 bucket = (struct rt6_exception_bucket *)p;
1605         }
1606
1607         return bucket;
1608 }
1609
1610 static bool fib6_nh_excptn_bucket_flushed(struct rt6_exception_bucket *bucket)
1611 {
1612         unsigned long p = (unsigned long)bucket;
1613
1614         return !!(p & FIB6_EXCEPTION_BUCKET_FLUSHED);
1615 }
1616
1617 /* called with rt6_exception_lock held */
1618 static void fib6_nh_excptn_bucket_set_flushed(struct fib6_nh *nh,
1619                                               spinlock_t *lock)
1620 {
1621         struct rt6_exception_bucket *bucket;
1622         unsigned long p;
1623
1624         bucket = rcu_dereference_protected(nh->rt6i_exception_bucket,
1625                                            lockdep_is_held(lock));
1626
1627         p = (unsigned long)bucket;
1628         p |= FIB6_EXCEPTION_BUCKET_FLUSHED;
1629         bucket = (struct rt6_exception_bucket *)p;
1630         rcu_assign_pointer(nh->rt6i_exception_bucket, bucket);
1631 }
1632
1633 static int rt6_insert_exception(struct rt6_info *nrt,
1634                                 const struct fib6_result *res)
1635 {
1636         struct net *net = dev_net(nrt->dst.dev);
1637         struct rt6_exception_bucket *bucket;
1638         struct fib6_info *f6i = res->f6i;
1639         struct in6_addr *src_key = NULL;
1640         struct rt6_exception *rt6_ex;
1641         struct fib6_nh *nh = res->nh;
1642         int err = 0;
1643
1644         spin_lock_bh(&rt6_exception_lock);
1645
1646         bucket = rcu_dereference_protected(nh->rt6i_exception_bucket,
1647                                           lockdep_is_held(&rt6_exception_lock));
1648         if (!bucket) {
1649                 bucket = kcalloc(FIB6_EXCEPTION_BUCKET_SIZE, sizeof(*bucket),
1650                                  GFP_ATOMIC);
1651                 if (!bucket) {
1652                         err = -ENOMEM;
1653                         goto out;
1654                 }
1655                 rcu_assign_pointer(nh->rt6i_exception_bucket, bucket);
1656         } else if (fib6_nh_excptn_bucket_flushed(bucket)) {
1657                 err = -EINVAL;
1658                 goto out;
1659         }
1660
1661 #ifdef CONFIG_IPV6_SUBTREES
1662         /* fib6_src.plen != 0 indicates f6i is in subtree
1663          * and exception table is indexed by a hash of
1664          * both fib6_dst and fib6_src.
1665          * Otherwise, the exception table is indexed by
1666          * a hash of only fib6_dst.
1667          */
1668         if (f6i->fib6_src.plen)
1669                 src_key = &nrt->rt6i_src.addr;
1670 #endif
1671         /* rt6_mtu_change() might lower mtu on f6i.
1672          * Only insert this exception route if its mtu
1673          * is less than f6i's mtu value.
1674          */
1675         if (dst_metric_raw(&nrt->dst, RTAX_MTU) >= fib6_mtu(res)) {
1676                 err = -EINVAL;
1677                 goto out;
1678         }
1679
1680         rt6_ex = __rt6_find_exception_spinlock(&bucket, &nrt->rt6i_dst.addr,
1681                                                src_key);
1682         if (rt6_ex)
1683                 rt6_remove_exception(bucket, rt6_ex);
1684
1685         rt6_ex = kzalloc(sizeof(*rt6_ex), GFP_ATOMIC);
1686         if (!rt6_ex) {
1687                 err = -ENOMEM;
1688                 goto out;
1689         }
1690         rt6_ex->rt6i = nrt;
1691         rt6_ex->stamp = jiffies;
1692         hlist_add_head_rcu(&rt6_ex->hlist, &bucket->chain);
1693         bucket->depth++;
1694         net->ipv6.rt6_stats->fib_rt_cache++;
1695
1696         if (bucket->depth > FIB6_MAX_DEPTH)
1697                 rt6_exception_remove_oldest(bucket);
1698
1699 out:
1700         spin_unlock_bh(&rt6_exception_lock);
1701
1702         /* Update fn->fn_sernum to invalidate all cached dst */
1703         if (!err) {
1704                 spin_lock_bh(&f6i->fib6_table->tb6_lock);
1705                 fib6_update_sernum(net, f6i);
1706                 spin_unlock_bh(&f6i->fib6_table->tb6_lock);
1707                 fib6_force_start_gc(net);
1708         }
1709
1710         return err;
1711 }
1712
1713 static void fib6_nh_flush_exceptions(struct fib6_nh *nh, struct fib6_info *from)
1714 {
1715         struct rt6_exception_bucket *bucket;
1716         struct rt6_exception *rt6_ex;
1717         struct hlist_node *tmp;
1718         int i;
1719
1720         spin_lock_bh(&rt6_exception_lock);
1721
1722         bucket = fib6_nh_get_excptn_bucket(nh, &rt6_exception_lock);
1723         if (!bucket)
1724                 goto out;
1725
1726         /* Prevent rt6_insert_exception() to recreate the bucket list */
1727         if (!from)
1728                 fib6_nh_excptn_bucket_set_flushed(nh, &rt6_exception_lock);
1729
1730         for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
1731                 hlist_for_each_entry_safe(rt6_ex, tmp, &bucket->chain, hlist) {
1732                         if (!from ||
1733                             rcu_access_pointer(rt6_ex->rt6i->from) == from)
1734                                 rt6_remove_exception(bucket, rt6_ex);
1735                 }
1736                 WARN_ON_ONCE(!from && bucket->depth);
1737                 bucket++;
1738         }
1739 out:
1740         spin_unlock_bh(&rt6_exception_lock);
1741 }
1742
1743 static int rt6_nh_flush_exceptions(struct fib6_nh *nh, void *arg)
1744 {
1745         struct fib6_info *f6i = arg;
1746
1747         fib6_nh_flush_exceptions(nh, f6i);
1748
1749         return 0;
1750 }
1751
1752 void rt6_flush_exceptions(struct fib6_info *f6i)
1753 {
1754         if (f6i->nh)
1755                 nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_flush_exceptions,
1756                                          f6i);
1757         else
1758                 fib6_nh_flush_exceptions(f6i->fib6_nh, f6i);
1759 }
1760
1761 /* Find cached rt in the hash table inside passed in rt
1762  * Caller has to hold rcu_read_lock()
1763  */
1764 static struct rt6_info *rt6_find_cached_rt(const struct fib6_result *res,
1765                                            const struct in6_addr *daddr,
1766                                            const struct in6_addr *saddr)
1767 {
1768         const struct in6_addr *src_key = NULL;
1769         struct rt6_exception_bucket *bucket;
1770         struct rt6_exception *rt6_ex;
1771         struct rt6_info *ret = NULL;
1772
1773 #ifdef CONFIG_IPV6_SUBTREES
1774         /* fib6i_src.plen != 0 indicates f6i is in subtree
1775          * and exception table is indexed by a hash of
1776          * both fib6_dst and fib6_src.
1777          * However, the src addr used to create the hash
1778          * might not be exactly the passed in saddr which
1779          * is a /128 addr from the flow.
1780          * So we need to use f6i->fib6_src to redo lookup
1781          * if the passed in saddr does not find anything.
1782          * (See the logic in ip6_rt_cache_alloc() on how
1783          * rt->rt6i_src is updated.)
1784          */
1785         if (res->f6i->fib6_src.plen)
1786                 src_key = saddr;
1787 find_ex:
1788 #endif
1789         bucket = fib6_nh_get_excptn_bucket(res->nh, NULL);
1790         rt6_ex = __rt6_find_exception_rcu(&bucket, daddr, src_key);
1791
1792         if (rt6_ex && !rt6_check_expired(rt6_ex->rt6i))
1793                 ret = rt6_ex->rt6i;
1794
1795 #ifdef CONFIG_IPV6_SUBTREES
1796         /* Use fib6_src as src_key and redo lookup */
1797         if (!ret && src_key && src_key != &res->f6i->fib6_src.addr) {
1798                 src_key = &res->f6i->fib6_src.addr;
1799                 goto find_ex;
1800         }
1801 #endif
1802
1803         return ret;
1804 }
1805
1806 /* Remove the passed in cached rt from the hash table that contains it */
1807 static int fib6_nh_remove_exception(const struct fib6_nh *nh, int plen,
1808                                     const struct rt6_info *rt)
1809 {
1810         const struct in6_addr *src_key = NULL;
1811         struct rt6_exception_bucket *bucket;
1812         struct rt6_exception *rt6_ex;
1813         int err;
1814
1815         if (!rcu_access_pointer(nh->rt6i_exception_bucket))
1816                 return -ENOENT;
1817
1818         spin_lock_bh(&rt6_exception_lock);
1819         bucket = fib6_nh_get_excptn_bucket(nh, &rt6_exception_lock);
1820
1821 #ifdef CONFIG_IPV6_SUBTREES
1822         /* rt6i_src.plen != 0 indicates 'from' is in subtree
1823          * and exception table is indexed by a hash of
1824          * both rt6i_dst and rt6i_src.
1825          * Otherwise, the exception table is indexed by
1826          * a hash of only rt6i_dst.
1827          */
1828         if (plen)
1829                 src_key = &rt->rt6i_src.addr;
1830 #endif
1831         rt6_ex = __rt6_find_exception_spinlock(&bucket,
1832                                                &rt->rt6i_dst.addr,
1833                                                src_key);
1834         if (rt6_ex) {
1835                 rt6_remove_exception(bucket, rt6_ex);
1836                 err = 0;
1837         } else {
1838                 err = -ENOENT;
1839         }
1840
1841         spin_unlock_bh(&rt6_exception_lock);
1842         return err;
1843 }
1844
1845 struct fib6_nh_excptn_arg {
1846         struct rt6_info *rt;
1847         int             plen;
1848 };
1849
1850 static int rt6_nh_remove_exception_rt(struct fib6_nh *nh, void *_arg)
1851 {
1852         struct fib6_nh_excptn_arg *arg = _arg;
1853         int err;
1854
1855         err = fib6_nh_remove_exception(nh, arg->plen, arg->rt);
1856         if (err == 0)
1857                 return 1;
1858
1859         return 0;
1860 }
1861
1862 static int rt6_remove_exception_rt(struct rt6_info *rt)
1863 {
1864         struct fib6_info *from;
1865
1866         from = rcu_dereference(rt->from);
1867         if (!from || !(rt->rt6i_flags & RTF_CACHE))
1868                 return -EINVAL;
1869
1870         if (from->nh) {
1871                 struct fib6_nh_excptn_arg arg = {
1872                         .rt = rt,
1873                         .plen = from->fib6_src.plen
1874                 };
1875                 int rc;
1876
1877                 /* rc = 1 means an entry was found */
1878                 rc = nexthop_for_each_fib6_nh(from->nh,
1879                                               rt6_nh_remove_exception_rt,
1880                                               &arg);
1881                 return rc ? 0 : -ENOENT;
1882         }
1883
1884         return fib6_nh_remove_exception(from->fib6_nh,
1885                                         from->fib6_src.plen, rt);
1886 }
1887
1888 /* Find rt6_ex which contains the passed in rt cache and
1889  * refresh its stamp
1890  */
1891 static void fib6_nh_update_exception(const struct fib6_nh *nh, int plen,
1892                                      const struct rt6_info *rt)
1893 {
1894         const struct in6_addr *src_key = NULL;
1895         struct rt6_exception_bucket *bucket;
1896         struct rt6_exception *rt6_ex;
1897
1898         bucket = fib6_nh_get_excptn_bucket(nh, NULL);
1899 #ifdef CONFIG_IPV6_SUBTREES
1900         /* rt6i_src.plen != 0 indicates 'from' is in subtree
1901          * and exception table is indexed by a hash of
1902          * both rt6i_dst and rt6i_src.
1903          * Otherwise, the exception table is indexed by
1904          * a hash of only rt6i_dst.
1905          */
1906         if (plen)
1907                 src_key = &rt->rt6i_src.addr;
1908 #endif
1909         rt6_ex = __rt6_find_exception_rcu(&bucket, &rt->rt6i_dst.addr, src_key);
1910         if (rt6_ex)
1911                 rt6_ex->stamp = jiffies;
1912 }
1913
1914 struct fib6_nh_match_arg {
1915         const struct net_device *dev;
1916         const struct in6_addr   *gw;
1917         struct fib6_nh          *match;
1918 };
1919
1920 /* determine if fib6_nh has given device and gateway */
1921 static int fib6_nh_find_match(struct fib6_nh *nh, void *_arg)
1922 {
1923         struct fib6_nh_match_arg *arg = _arg;
1924
1925         if (arg->dev != nh->fib_nh_dev ||
1926             (arg->gw && !nh->fib_nh_gw_family) ||
1927             (!arg->gw && nh->fib_nh_gw_family) ||
1928             (arg->gw && !ipv6_addr_equal(arg->gw, &nh->fib_nh_gw6)))
1929                 return 0;
1930
1931         arg->match = nh;
1932
1933         /* found a match, break the loop */
1934         return 1;
1935 }
1936
1937 static void rt6_update_exception_stamp_rt(struct rt6_info *rt)
1938 {
1939         struct fib6_info *from;
1940         struct fib6_nh *fib6_nh;
1941
1942         rcu_read_lock();
1943
1944         from = rcu_dereference(rt->from);
1945         if (!from || !(rt->rt6i_flags & RTF_CACHE))
1946                 goto unlock;
1947
1948         if (from->nh) {
1949                 struct fib6_nh_match_arg arg = {
1950                         .dev = rt->dst.dev,
1951                         .gw = &rt->rt6i_gateway,
1952                 };
1953
1954                 nexthop_for_each_fib6_nh(from->nh, fib6_nh_find_match, &arg);
1955
1956                 if (!arg.match)
1957                         goto unlock;
1958                 fib6_nh = arg.match;
1959         } else {
1960                 fib6_nh = from->fib6_nh;
1961         }
1962         fib6_nh_update_exception(fib6_nh, from->fib6_src.plen, rt);
1963 unlock:
1964         rcu_read_unlock();
1965 }
1966
1967 static bool rt6_mtu_change_route_allowed(struct inet6_dev *idev,
1968                                          struct rt6_info *rt, int mtu)
1969 {
1970         /* If the new MTU is lower than the route PMTU, this new MTU will be the
1971          * lowest MTU in the path: always allow updating the route PMTU to
1972          * reflect PMTU decreases.
1973          *
1974          * If the new MTU is higher, and the route PMTU is equal to the local
1975          * MTU, this means the old MTU is the lowest in the path, so allow
1976          * updating it: if other nodes now have lower MTUs, PMTU discovery will
1977          * handle this.
1978          */
1979
1980         if (dst_mtu(&rt->dst) >= mtu)
1981                 return true;
1982
1983         if (dst_mtu(&rt->dst) == idev->cnf.mtu6)
1984                 return true;
1985
1986         return false;
1987 }
1988
1989 static void rt6_exceptions_update_pmtu(struct inet6_dev *idev,
1990                                        const struct fib6_nh *nh, int mtu)
1991 {
1992         struct rt6_exception_bucket *bucket;
1993         struct rt6_exception *rt6_ex;
1994         int i;
1995
1996         bucket = fib6_nh_get_excptn_bucket(nh, &rt6_exception_lock);
1997         if (!bucket)
1998                 return;
1999
2000         for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
2001                 hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
2002                         struct rt6_info *entry = rt6_ex->rt6i;
2003
2004                         /* For RTF_CACHE with rt6i_pmtu == 0 (i.e. a redirected
2005                          * route), the metrics of its rt->from have already
2006                          * been updated.
2007                          */
2008                         if (dst_metric_raw(&entry->dst, RTAX_MTU) &&
2009                             rt6_mtu_change_route_allowed(idev, entry, mtu))
2010                                 dst_metric_set(&entry->dst, RTAX_MTU, mtu);
2011                 }
2012                 bucket++;
2013         }
2014 }
2015
2016 #define RTF_CACHE_GATEWAY       (RTF_GATEWAY | RTF_CACHE)
2017
2018 static void fib6_nh_exceptions_clean_tohost(const struct fib6_nh *nh,
2019                                             const struct in6_addr *gateway)
2020 {
2021         struct rt6_exception_bucket *bucket;
2022         struct rt6_exception *rt6_ex;
2023         struct hlist_node *tmp;
2024         int i;
2025
2026         if (!rcu_access_pointer(nh->rt6i_exception_bucket))
2027                 return;
2028
2029         spin_lock_bh(&rt6_exception_lock);
2030         bucket = fib6_nh_get_excptn_bucket(nh, &rt6_exception_lock);
2031         if (bucket) {
2032                 for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
2033                         hlist_for_each_entry_safe(rt6_ex, tmp,
2034                                                   &bucket->chain, hlist) {
2035                                 struct rt6_info *entry = rt6_ex->rt6i;
2036
2037                                 if ((entry->rt6i_flags & RTF_CACHE_GATEWAY) ==
2038                                     RTF_CACHE_GATEWAY &&
2039                                     ipv6_addr_equal(gateway,
2040                                                     &entry->rt6i_gateway)) {
2041                                         rt6_remove_exception(bucket, rt6_ex);
2042                                 }
2043                         }
2044                         bucket++;
2045                 }
2046         }
2047
2048         spin_unlock_bh(&rt6_exception_lock);
2049 }
2050
2051 static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket,
2052                                       struct rt6_exception *rt6_ex,
2053                                       struct fib6_gc_args *gc_args,
2054                                       unsigned long now)
2055 {
2056         struct rt6_info *rt = rt6_ex->rt6i;
2057
2058         /* we are pruning and obsoleting aged-out and non gateway exceptions
2059          * even if others have still references to them, so that on next
2060          * dst_check() such references can be dropped.
2061          * EXPIRES exceptions - e.g. pmtu-generated ones are pruned when
2062          * expired, independently from their aging, as per RFC 8201 section 4
2063          */
2064         if (!(rt->rt6i_flags & RTF_EXPIRES)) {
2065                 if (time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
2066                         RT6_TRACE("aging clone %p\n", rt);
2067                         rt6_remove_exception(bucket, rt6_ex);
2068                         return;
2069                 }
2070         } else if (time_after(jiffies, rt->dst.expires)) {
2071                 RT6_TRACE("purging expired route %p\n", rt);
2072                 rt6_remove_exception(bucket, rt6_ex);
2073                 return;
2074         }
2075
2076         if (rt->rt6i_flags & RTF_GATEWAY) {
2077                 struct neighbour *neigh;
2078                 __u8 neigh_flags = 0;
2079
2080                 neigh = __ipv6_neigh_lookup_noref(rt->dst.dev, &rt->rt6i_gateway);
2081                 if (neigh)
2082                         neigh_flags = neigh->flags;
2083
2084                 if (!(neigh_flags & NTF_ROUTER)) {
2085                         RT6_TRACE("purging route %p via non-router but gateway\n",
2086                                   rt);
2087                         rt6_remove_exception(bucket, rt6_ex);
2088                         return;
2089                 }
2090         }
2091
2092         gc_args->more++;
2093 }
2094
2095 static void fib6_nh_age_exceptions(const struct fib6_nh *nh,
2096                                    struct fib6_gc_args *gc_args,
2097                                    unsigned long now)
2098 {
2099         struct rt6_exception_bucket *bucket;
2100         struct rt6_exception *rt6_ex;
2101         struct hlist_node *tmp;
2102         int i;
2103
2104         if (!rcu_access_pointer(nh->rt6i_exception_bucket))
2105                 return;
2106
2107         rcu_read_lock_bh();
2108         spin_lock(&rt6_exception_lock);
2109         bucket = fib6_nh_get_excptn_bucket(nh, &rt6_exception_lock);
2110         if (bucket) {
2111                 for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
2112                         hlist_for_each_entry_safe(rt6_ex, tmp,
2113                                                   &bucket->chain, hlist) {
2114                                 rt6_age_examine_exception(bucket, rt6_ex,
2115                                                           gc_args, now);
2116                         }
2117                         bucket++;
2118                 }
2119         }
2120         spin_unlock(&rt6_exception_lock);
2121         rcu_read_unlock_bh();
2122 }
2123
2124 struct fib6_nh_age_excptn_arg {
2125         struct fib6_gc_args     *gc_args;
2126         unsigned long           now;
2127 };
2128
2129 static int rt6_nh_age_exceptions(struct fib6_nh *nh, void *_arg)
2130 {
2131         struct fib6_nh_age_excptn_arg *arg = _arg;
2132
2133         fib6_nh_age_exceptions(nh, arg->gc_args, arg->now);
2134         return 0;
2135 }
2136
2137 void rt6_age_exceptions(struct fib6_info *f6i,
2138                         struct fib6_gc_args *gc_args,
2139                         unsigned long now)
2140 {
2141         if (f6i->nh) {
2142                 struct fib6_nh_age_excptn_arg arg = {
2143                         .gc_args = gc_args,
2144                         .now = now
2145                 };
2146
2147                 nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_age_exceptions,
2148                                          &arg);
2149         } else {
2150                 fib6_nh_age_exceptions(f6i->fib6_nh, gc_args, now);
2151         }
2152 }
2153
2154 /* must be called with rcu lock held */
2155 int fib6_table_lookup(struct net *net, struct fib6_table *table, int oif,
2156                       struct flowi6 *fl6, struct fib6_result *res, int strict)
2157 {
2158         struct fib6_node *fn, *saved_fn;
2159
2160         fn = fib6_node_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
2161         saved_fn = fn;
2162
2163         if (fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF)
2164                 oif = 0;
2165
2166 redo_rt6_select:
2167         rt6_select(net, fn, oif, res, strict);
2168         if (res->f6i == net->ipv6.fib6_null_entry) {
2169                 fn = fib6_backtrack(fn, &fl6->saddr);
2170                 if (fn)
2171                         goto redo_rt6_select;
2172                 else if (strict & RT6_LOOKUP_F_REACHABLE) {
2173                         /* also consider unreachable route */
2174                         strict &= ~RT6_LOOKUP_F_REACHABLE;
2175                         fn = saved_fn;
2176                         goto redo_rt6_select;
2177                 }
2178         }
2179
2180         trace_fib6_table_lookup(net, res, table, fl6);
2181
2182         return 0;
2183 }
2184
2185 struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
2186                                int oif, struct flowi6 *fl6,
2187                                const struct sk_buff *skb, int flags)
2188 {
2189         struct fib6_result res = {};
2190         struct rt6_info *rt = NULL;
2191         int strict = 0;
2192
2193         WARN_ON_ONCE((flags & RT6_LOOKUP_F_DST_NOREF) &&
2194                      !rcu_read_lock_held());
2195
2196         strict |= flags & RT6_LOOKUP_F_IFACE;
2197         strict |= flags & RT6_LOOKUP_F_IGNORE_LINKSTATE;
2198         if (net->ipv6.devconf_all->forwarding == 0)
2199                 strict |= RT6_LOOKUP_F_REACHABLE;
2200
2201         rcu_read_lock();
2202
2203         fib6_table_lookup(net, table, oif, fl6, &res, strict);
2204         if (res.f6i == net->ipv6.fib6_null_entry)
2205                 goto out;
2206
2207         fib6_select_path(net, &res, fl6, oif, false, skb, strict);
2208
2209         /*Search through exception table */
2210         rt = rt6_find_cached_rt(&res, &fl6->daddr, &fl6->saddr);
2211         if (rt) {
2212                 goto out;
2213         } else if (unlikely((fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH) &&
2214                             !res.nh->fib_nh_gw_family)) {
2215                 /* Create a RTF_CACHE clone which will not be
2216                  * owned by the fib6 tree.  It is for the special case where
2217                  * the daddr in the skb during the neighbor look-up is different
2218                  * from the fl6->daddr used to look-up route here.
2219                  */
2220                 rt = ip6_rt_cache_alloc(&res, &fl6->daddr, NULL);
2221
2222                 if (rt) {
2223                         /* 1 refcnt is taken during ip6_rt_cache_alloc().
2224                          * As rt6_uncached_list_add() does not consume refcnt,
2225                          * this refcnt is always returned to the caller even
2226                          * if caller sets RT6_LOOKUP_F_DST_NOREF flag.
2227                          */
2228                         rt6_uncached_list_add(rt);
2229                         atomic_inc(&net->ipv6.rt6_stats->fib_rt_uncache);
2230                         rcu_read_unlock();
2231
2232                         return rt;
2233                 }
2234         } else {
2235                 /* Get a percpu copy */
2236                 local_bh_disable();
2237                 rt = rt6_get_pcpu_route(&res);
2238
2239                 if (!rt)
2240                         rt = rt6_make_pcpu_route(net, &res);
2241
2242                 local_bh_enable();
2243         }
2244 out:
2245         if (!rt)
2246                 rt = net->ipv6.ip6_null_entry;
2247         if (!(flags & RT6_LOOKUP_F_DST_NOREF))
2248                 ip6_hold_safe(net, &rt);
2249         rcu_read_unlock();
2250
2251         return rt;
2252 }
2253 EXPORT_SYMBOL_GPL(ip6_pol_route);
2254
2255 static struct rt6_info *ip6_pol_route_input(struct net *net,
2256                                             struct fib6_table *table,
2257                                             struct flowi6 *fl6,
2258                                             const struct sk_buff *skb,
2259                                             int flags)
2260 {
2261         return ip6_pol_route(net, table, fl6->flowi6_iif, fl6, skb, flags);
2262 }
2263
2264 struct dst_entry *ip6_route_input_lookup(struct net *net,
2265                                          struct net_device *dev,
2266                                          struct flowi6 *fl6,
2267                                          const struct sk_buff *skb,
2268                                          int flags)
2269 {
2270         if (rt6_need_strict(&fl6->daddr) && dev->type != ARPHRD_PIMREG)
2271                 flags |= RT6_LOOKUP_F_IFACE;
2272
2273         return fib6_rule_lookup(net, fl6, skb, flags, ip6_pol_route_input);
2274 }
2275 EXPORT_SYMBOL_GPL(ip6_route_input_lookup);
2276
2277 static void ip6_multipath_l3_keys(const struct sk_buff *skb,
2278                                   struct flow_keys *keys,
2279                                   struct flow_keys *flkeys)
2280 {
2281         const struct ipv6hdr *outer_iph = ipv6_hdr(skb);
2282         const struct ipv6hdr *key_iph = outer_iph;
2283         struct flow_keys *_flkeys = flkeys;
2284         const struct ipv6hdr *inner_iph;
2285         const struct icmp6hdr *icmph;
2286         struct ipv6hdr _inner_iph;
2287         struct icmp6hdr _icmph;
2288
2289         if (likely(outer_iph->nexthdr != IPPROTO_ICMPV6))
2290                 goto out;
2291
2292         icmph = skb_header_pointer(skb, skb_transport_offset(skb),
2293                                    sizeof(_icmph), &_icmph);
2294         if (!icmph)
2295                 goto out;
2296
2297         if (!icmpv6_is_err(icmph->icmp6_type))
2298                 goto out;
2299
2300         inner_iph = skb_header_pointer(skb,
2301                                        skb_transport_offset(skb) + sizeof(*icmph),
2302                                        sizeof(_inner_iph), &_inner_iph);
2303         if (!inner_iph)
2304                 goto out;
2305
2306         key_iph = inner_iph;
2307         _flkeys = NULL;
2308 out:
2309         if (_flkeys) {
2310                 keys->addrs.v6addrs.src = _flkeys->addrs.v6addrs.src;
2311                 keys->addrs.v6addrs.dst = _flkeys->addrs.v6addrs.dst;
2312                 keys->tags.flow_label = _flkeys->tags.flow_label;
2313                 keys->basic.ip_proto = _flkeys->basic.ip_proto;
2314         } else {
2315                 keys->addrs.v6addrs.src = key_iph->saddr;
2316                 keys->addrs.v6addrs.dst = key_iph->daddr;
2317                 keys->tags.flow_label = ip6_flowlabel(key_iph);
2318                 keys->basic.ip_proto = key_iph->nexthdr;
2319         }
2320 }
2321
2322 /* if skb is set it will be used and fl6 can be NULL */
2323 u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
2324                        const struct sk_buff *skb, struct flow_keys *flkeys)
2325 {
2326         struct flow_keys hash_keys;
2327         u32 mhash;
2328
2329         switch (ip6_multipath_hash_policy(net)) {
2330         case 0:
2331                 memset(&hash_keys, 0, sizeof(hash_keys));
2332                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2333                 if (skb) {
2334                         ip6_multipath_l3_keys(skb, &hash_keys, flkeys);
2335                 } else {
2336                         hash_keys.addrs.v6addrs.src = fl6->saddr;
2337                         hash_keys.addrs.v6addrs.dst = fl6->daddr;
2338                         hash_keys.tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6);
2339                         hash_keys.basic.ip_proto = fl6->flowi6_proto;
2340                 }
2341                 break;
2342         case 1:
2343                 if (skb) {
2344                         unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2345                         struct flow_keys keys;
2346
2347                         /* short-circuit if we already have L4 hash present */
2348                         if (skb->l4_hash)
2349                                 return skb_get_hash_raw(skb) >> 1;
2350
2351                         memset(&hash_keys, 0, sizeof(hash_keys));
2352
2353                         if (!flkeys) {
2354                                 skb_flow_dissect_flow_keys(skb, &keys, flag);
2355                                 flkeys = &keys;
2356                         }
2357                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2358                         hash_keys.addrs.v6addrs.src = flkeys->addrs.v6addrs.src;
2359                         hash_keys.addrs.v6addrs.dst = flkeys->addrs.v6addrs.dst;
2360                         hash_keys.ports.src = flkeys->ports.src;
2361                         hash_keys.ports.dst = flkeys->ports.dst;
2362                         hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2363                 } else {
2364                         memset(&hash_keys, 0, sizeof(hash_keys));
2365                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2366                         hash_keys.addrs.v6addrs.src = fl6->saddr;
2367                         hash_keys.addrs.v6addrs.dst = fl6->daddr;
2368                         hash_keys.ports.src = fl6->fl6_sport;
2369                         hash_keys.ports.dst = fl6->fl6_dport;
2370                         hash_keys.basic.ip_proto = fl6->flowi6_proto;
2371                 }
2372                 break;
2373         case 2:
2374                 memset(&hash_keys, 0, sizeof(hash_keys));
2375                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2376                 if (skb) {
2377                         struct flow_keys keys;
2378
2379                         if (!flkeys) {
2380                                 skb_flow_dissect_flow_keys(skb, &keys, 0);
2381                                 flkeys = &keys;
2382                         }
2383
2384                         /* Inner can be v4 or v6 */
2385                         if (flkeys->control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2386                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2387                                 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2388                                 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2389                         } else if (flkeys->control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2390                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2391                                 hash_keys.addrs.v6addrs.src = flkeys->addrs.v6addrs.src;
2392                                 hash_keys.addrs.v6addrs.dst = flkeys->addrs.v6addrs.dst;
2393                                 hash_keys.tags.flow_label = flkeys->tags.flow_label;
2394                                 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2395                         } else {
2396                                 /* Same as case 0 */
2397                                 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2398                                 ip6_multipath_l3_keys(skb, &hash_keys, flkeys);
2399                         }
2400                 } else {
2401                         /* Same as case 0 */
2402                         hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2403                         hash_keys.addrs.v6addrs.src = fl6->saddr;
2404                         hash_keys.addrs.v6addrs.dst = fl6->daddr;
2405                         hash_keys.tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6);
2406                         hash_keys.basic.ip_proto = fl6->flowi6_proto;
2407                 }
2408                 break;
2409         }
2410         mhash = flow_hash_from_keys(&hash_keys);
2411
2412         return mhash >> 1;
2413 }
2414
2415 /* Called with rcu held */
2416 void ip6_route_input(struct sk_buff *skb)
2417 {
2418         const struct ipv6hdr *iph = ipv6_hdr(skb);
2419         struct net *net = dev_net(skb->dev);
2420         int flags = RT6_LOOKUP_F_HAS_SADDR | RT6_LOOKUP_F_DST_NOREF;
2421         struct ip_tunnel_info *tun_info;
2422         struct flowi6 fl6 = {
2423                 .flowi6_iif = skb->dev->ifindex,
2424                 .daddr = iph->daddr,
2425                 .saddr = iph->saddr,
2426                 .flowlabel = ip6_flowinfo(iph),
2427                 .flowi6_mark = skb->mark,
2428                 .flowi6_proto = iph->nexthdr,
2429         };
2430         struct flow_keys *flkeys = NULL, _flkeys;
2431
2432         tun_info = skb_tunnel_info(skb);
2433         if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2434                 fl6.flowi6_tun_key.tun_id = tun_info->key.tun_id;
2435
2436         if (fib6_rules_early_flow_dissect(net, skb, &fl6, &_flkeys))
2437                 flkeys = &_flkeys;
2438
2439         if (unlikely(fl6.flowi6_proto == IPPROTO_ICMPV6))
2440                 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, flkeys);
2441         skb_dst_drop(skb);
2442         skb_dst_set_noref(skb, ip6_route_input_lookup(net, skb->dev,
2443                                                       &fl6, skb, flags));
2444 }
2445
2446 static struct rt6_info *ip6_pol_route_output(struct net *net,
2447                                              struct fib6_table *table,
2448                                              struct flowi6 *fl6,
2449                                              const struct sk_buff *skb,
2450                                              int flags)
2451 {
2452         return ip6_pol_route(net, table, fl6->flowi6_oif, fl6, skb, flags);
2453 }
2454
2455 struct dst_entry *ip6_route_output_flags_noref(struct net *net,
2456                                                const struct sock *sk,
2457                                                struct flowi6 *fl6, int flags)
2458 {
2459         bool any_src;
2460
2461         if (ipv6_addr_type(&fl6->daddr) &
2462             (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL)) {
2463                 struct dst_entry *dst;
2464
2465                 /* This function does not take refcnt on the dst */
2466                 dst = l3mdev_link_scope_lookup(net, fl6);
2467                 if (dst)
2468                         return dst;
2469         }
2470
2471         fl6->flowi6_iif = LOOPBACK_IFINDEX;
2472
2473         flags |= RT6_LOOKUP_F_DST_NOREF;
2474         any_src = ipv6_addr_any(&fl6->saddr);
2475         if ((sk && sk->sk_bound_dev_if) || rt6_need_strict(&fl6->daddr) ||
2476             (fl6->flowi6_oif && any_src))
2477                 flags |= RT6_LOOKUP_F_IFACE;
2478
2479         if (!any_src)
2480                 flags |= RT6_LOOKUP_F_HAS_SADDR;
2481         else if (sk)
2482                 flags |= rt6_srcprefs2flags(inet6_sk(sk)->srcprefs);
2483
2484         return fib6_rule_lookup(net, fl6, NULL, flags, ip6_pol_route_output);
2485 }
2486 EXPORT_SYMBOL_GPL(ip6_route_output_flags_noref);
2487
2488 struct dst_entry *ip6_route_output_flags(struct net *net,
2489                                          const struct sock *sk,
2490                                          struct flowi6 *fl6,
2491                                          int flags)
2492 {
2493         struct dst_entry *dst;
2494         struct rt6_info *rt6;
2495
2496         rcu_read_lock();
2497         dst = ip6_route_output_flags_noref(net, sk, fl6, flags);
2498         rt6 = (struct rt6_info *)dst;
2499         /* For dst cached in uncached_list, refcnt is already taken. */
2500         if (list_empty(&rt6->rt6i_uncached) && !dst_hold_safe(dst)) {
2501                 dst = &net->ipv6.ip6_null_entry->dst;
2502                 dst_hold(dst);
2503         }
2504         rcu_read_unlock();
2505
2506         return dst;
2507 }
2508 EXPORT_SYMBOL_GPL(ip6_route_output_flags);
2509
2510 struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2511 {
2512         struct rt6_info *rt, *ort = (struct rt6_info *) dst_orig;
2513         struct net_device *loopback_dev = net->loopback_dev;
2514         struct dst_entry *new = NULL;
2515
2516         rt = dst_alloc(&ip6_dst_blackhole_ops, loopback_dev, 1,
2517                        DST_OBSOLETE_DEAD, 0);
2518         if (rt) {
2519                 rt6_info_init(rt);
2520                 atomic_inc(&net->ipv6.rt6_stats->fib_rt_alloc);
2521
2522                 new = &rt->dst;
2523                 new->__use = 1;
2524                 new->input = dst_discard;
2525                 new->output = dst_discard_out;
2526
2527                 dst_copy_metrics(new, &ort->dst);
2528
2529                 rt->rt6i_idev = in6_dev_get(loopback_dev);
2530                 rt->rt6i_gateway = ort->rt6i_gateway;
2531                 rt->rt6i_flags = ort->rt6i_flags & ~RTF_PCPU;
2532
2533                 memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));
2534 #ifdef CONFIG_IPV6_SUBTREES
2535                 memcpy(&rt->rt6i_src, &ort->rt6i_src, sizeof(struct rt6key));
2536 #endif
2537         }
2538
2539         dst_release(dst_orig);
2540         return new ? new : ERR_PTR(-ENOMEM);
2541 }
2542
2543 /*
2544  *      Destination cache support functions
2545  */
2546
2547 static bool fib6_check(struct fib6_info *f6i, u32 cookie)
2548 {
2549         u32 rt_cookie = 0;
2550
2551         if (!fib6_get_cookie_safe(f6i, &rt_cookie) || rt_cookie != cookie)
2552                 return false;
2553
2554         if (fib6_check_expired(f6i))
2555                 return false;
2556
2557         return true;
2558 }
2559
2560 static struct dst_entry *rt6_check(struct rt6_info *rt,
2561                                    struct fib6_info *from,
2562                                    u32 cookie)
2563 {
2564         u32 rt_cookie = 0;
2565
2566         if (!from || !fib6_get_cookie_safe(from, &rt_cookie) ||
2567             rt_cookie != cookie)
2568                 return NULL;
2569
2570         if (rt6_check_expired(rt))
2571                 return NULL;
2572
2573         return &rt->dst;
2574 }
2575
2576 static struct dst_entry *rt6_dst_from_check(struct rt6_info *rt,
2577                                             struct fib6_info *from,
2578                                             u32 cookie)
2579 {
2580         if (!__rt6_check_expired(rt) &&
2581             rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
2582             fib6_check(from, cookie))
2583                 return &rt->dst;
2584         else
2585                 return NULL;
2586 }
2587
2588 static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
2589 {
2590         struct dst_entry *dst_ret;
2591         struct fib6_info *from;
2592         struct rt6_info *rt;
2593
2594         rt = container_of(dst, struct rt6_info, dst);
2595
2596         rcu_read_lock();
2597
2598         /* All IPV6 dsts are created with ->obsolete set to the value
2599          * DST_OBSOLETE_FORCE_CHK which forces validation calls down
2600          * into this function always.
2601          */
2602
2603         from = rcu_dereference(rt->from);
2604
2605         if (from && (rt->rt6i_flags & RTF_PCPU ||
2606             unlikely(!list_empty(&rt->rt6i_uncached))))
2607                 dst_ret = rt6_dst_from_check(rt, from, cookie);
2608         else
2609                 dst_ret = rt6_check(rt, from, cookie);
2610
2611         rcu_read_unlock();
2612
2613         return dst_ret;
2614 }
2615
2616 static struct dst_entry *ip6_negative_advice(struct dst_entry *dst)
2617 {
2618         struct rt6_info *rt = (struct rt6_info *) dst;
2619
2620         if (rt) {
2621                 if (rt->rt6i_flags & RTF_CACHE) {
2622                         rcu_read_lock();
2623                         if (rt6_check_expired(rt)) {
2624                                 rt6_remove_exception_rt(rt);
2625                                 dst = NULL;
2626                         }
2627                         rcu_read_unlock();
2628                 } else {
2629                         dst_release(dst);
2630                         dst = NULL;
2631                 }
2632         }
2633         return dst;
2634 }
2635
2636 static void ip6_link_failure(struct sk_buff *skb)
2637 {
2638         struct rt6_info *rt;
2639
2640         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
2641
2642         rt = (struct rt6_info *) skb_dst(skb);
2643         if (rt) {
2644                 rcu_read_lock();
2645                 if (rt->rt6i_flags & RTF_CACHE) {
2646                         rt6_remove_exception_rt(rt);
2647                 } else {
2648                         struct fib6_info *from;
2649                         struct fib6_node *fn;
2650
2651                         from = rcu_dereference(rt->from);
2652                         if (from) {
2653                                 fn = rcu_dereference(from->fib6_node);
2654                                 if (fn && (rt->rt6i_flags & RTF_DEFAULT))
2655                                         fn->fn_sernum = -1;
2656                         }
2657                 }
2658                 rcu_read_unlock();
2659         }
2660 }
2661
2662 static void rt6_update_expires(struct rt6_info *rt0, int timeout)
2663 {
2664         if (!(rt0->rt6i_flags & RTF_EXPIRES)) {
2665                 struct fib6_info *from;
2666
2667                 rcu_read_lock();
2668                 from = rcu_dereference(rt0->from);
2669                 if (from)
2670                         rt0->dst.expires = from->expires;
2671                 rcu_read_unlock();
2672         }
2673
2674         dst_set_expires(&rt0->dst, timeout);
2675         rt0->rt6i_flags |= RTF_EXPIRES;
2676 }
2677
2678 static void rt6_do_update_pmtu(struct rt6_info *rt, u32 mtu)
2679 {
2680         struct net *net = dev_net(rt->dst.dev);
2681
2682         dst_metric_set(&rt->dst, RTAX_MTU, mtu);
2683         rt->rt6i_flags |= RTF_MODIFIED;
2684         rt6_update_expires(rt, net->ipv6.sysctl.ip6_rt_mtu_expires);
2685 }
2686
2687 static bool rt6_cache_allowed_for_pmtu(const struct rt6_info *rt)
2688 {
2689         return !(rt->rt6i_flags & RTF_CACHE) &&
2690                 (rt->rt6i_flags & RTF_PCPU || rcu_access_pointer(rt->from));
2691 }
2692
2693 static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk,
2694                                  const struct ipv6hdr *iph, u32 mtu,
2695                                  bool confirm_neigh)
2696 {
2697         const struct in6_addr *daddr, *saddr;
2698         struct rt6_info *rt6 = (struct rt6_info *)dst;
2699
2700         if (dst_metric_locked(dst, RTAX_MTU))
2701                 return;
2702
2703         if (iph) {
2704                 daddr = &iph->daddr;
2705                 saddr = &iph->saddr;
2706         } else if (sk) {
2707                 daddr = &sk->sk_v6_daddr;
2708                 saddr = &inet6_sk(sk)->saddr;
2709         } else {
2710                 daddr = NULL;
2711                 saddr = NULL;
2712         }
2713
2714         if (confirm_neigh)
2715                 dst_confirm_neigh(dst, daddr);
2716
2717         mtu = max_t(u32, mtu, IPV6_MIN_MTU);
2718         if (mtu >= dst_mtu(dst))
2719                 return;
2720
2721         if (!rt6_cache_allowed_for_pmtu(rt6)) {
2722                 rt6_do_update_pmtu(rt6, mtu);
2723                 /* update rt6_ex->stamp for cache */
2724                 if (rt6->rt6i_flags & RTF_CACHE)
2725                         rt6_update_exception_stamp_rt(rt6);
2726         } else if (daddr) {
2727                 struct fib6_result res = {};
2728                 struct rt6_info *nrt6;
2729
2730                 rcu_read_lock();
2731                 res.f6i = rcu_dereference(rt6->from);
2732                 if (!res.f6i)
2733                         goto out_unlock;
2734
2735                 res.fib6_flags = res.f6i->fib6_flags;
2736                 res.fib6_type = res.f6i->fib6_type;
2737
2738                 if (res.f6i->nh) {
2739                         struct fib6_nh_match_arg arg = {
2740                                 .dev = dst->dev,
2741                                 .gw = &rt6->rt6i_gateway,
2742                         };
2743
2744                         nexthop_for_each_fib6_nh(res.f6i->nh,
2745                                                  fib6_nh_find_match, &arg);
2746
2747                         /* fib6_info uses a nexthop that does not have fib6_nh
2748                          * using the dst->dev + gw. Should be impossible.
2749                          */
2750                         if (!arg.match)
2751                                 goto out_unlock;
2752
2753                         res.nh = arg.match;
2754                 } else {
2755                         res.nh = res.f6i->fib6_nh;
2756                 }
2757
2758                 nrt6 = ip6_rt_cache_alloc(&res, daddr, saddr);
2759                 if (nrt6) {
2760                         rt6_do_update_pmtu(nrt6, mtu);
2761                         if (rt6_insert_exception(nrt6, &res))
2762                                 dst_release_immediate(&nrt6->dst);
2763                 }
2764 out_unlock:
2765                 rcu_read_unlock();
2766         }
2767 }
2768
2769 static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
2770                                struct sk_buff *skb, u32 mtu,
2771                                bool confirm_neigh)
2772 {
2773         __ip6_rt_update_pmtu(dst, sk, skb ? ipv6_hdr(skb) : NULL, mtu,
2774                              confirm_neigh);
2775 }
2776
2777 void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
2778                      int oif, u32 mark, kuid_t uid)
2779 {
2780         const struct ipv6hdr *iph = (struct ipv6hdr *) skb->data;
2781         struct dst_entry *dst;
2782         struct flowi6 fl6 = {
2783                 .flowi6_oif = oif,
2784                 .flowi6_mark = mark ? mark : IP6_REPLY_MARK(net, skb->mark),
2785                 .daddr = iph->daddr,
2786                 .saddr = iph->saddr,
2787                 .flowlabel = ip6_flowinfo(iph),
2788                 .flowi6_uid = uid,
2789         };
2790
2791         dst = ip6_route_output(net, NULL, &fl6);
2792         if (!dst->error)
2793                 __ip6_rt_update_pmtu(dst, NULL, iph, ntohl(mtu), true);
2794         dst_release(dst);
2795 }
2796 EXPORT_SYMBOL_GPL(ip6_update_pmtu);
2797
2798 void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu)
2799 {
2800         int oif = sk->sk_bound_dev_if;
2801         struct dst_entry *dst;
2802
2803         if (!oif && skb->dev)
2804                 oif = l3mdev_master_ifindex(skb->dev);
2805
2806         ip6_update_pmtu(skb, sock_net(sk), mtu, oif, sk->sk_mark, sk->sk_uid);
2807
2808         dst = __sk_dst_get(sk);
2809         if (!dst || !dst->obsolete ||
2810             dst->ops->check(dst, inet6_sk(sk)->dst_cookie))
2811                 return;
2812
2813         bh_lock_sock(sk);
2814         if (!sock_owned_by_user(sk) && !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
2815                 ip6_datagram_dst_update(sk, false);
2816         bh_unlock_sock(sk);
2817 }
2818 EXPORT_SYMBOL_GPL(ip6_sk_update_pmtu);
2819
2820 void ip6_sk_dst_store_flow(struct sock *sk, struct dst_entry *dst,
2821                            const struct flowi6 *fl6)
2822 {
2823 #ifdef CONFIG_IPV6_SUBTREES
2824         struct ipv6_pinfo *np = inet6_sk(sk);
2825 #endif
2826
2827         ip6_dst_store(sk, dst,
2828                       ipv6_addr_equal(&fl6->daddr, &sk->sk_v6_daddr) ?
2829                       &sk->sk_v6_daddr : NULL,
2830 #ifdef CONFIG_IPV6_SUBTREES
2831                       ipv6_addr_equal(&fl6->saddr, &np->saddr) ?
2832                       &np->saddr :
2833 #endif
2834                       NULL);
2835 }
2836
2837 static bool ip6_redirect_nh_match(const struct fib6_result *res,
2838                                   struct flowi6 *fl6,
2839                                   const struct in6_addr *gw,
2840                                   struct rt6_info **ret)
2841 {
2842         const struct fib6_nh *nh = res->nh;
2843
2844         if (nh->fib_nh_flags & RTNH_F_DEAD || !nh->fib_nh_gw_family ||
2845             fl6->flowi6_oif != nh->fib_nh_dev->ifindex)
2846                 return false;
2847
2848         /* rt_cache's gateway might be different from its 'parent'
2849          * in the case of an ip redirect.
2850          * So we keep searching in the exception table if the gateway
2851          * is different.
2852          */
2853         if (!ipv6_addr_equal(gw, &nh->fib_nh_gw6)) {
2854                 struct rt6_info *rt_cache;
2855
2856                 rt_cache = rt6_find_cached_rt(res, &fl6->daddr, &fl6->saddr);
2857                 if (rt_cache &&
2858                     ipv6_addr_equal(gw, &rt_cache->rt6i_gateway)) {
2859                         *ret = rt_cache;
2860                         return true;
2861                 }
2862                 return false;
2863         }
2864         return true;
2865 }
2866
2867 struct fib6_nh_rd_arg {
2868         struct fib6_result      *res;
2869         struct flowi6           *fl6;
2870         const struct in6_addr   *gw;
2871         struct rt6_info         **ret;
2872 };
2873
2874 static int fib6_nh_redirect_match(struct fib6_nh *nh, void *_arg)
2875 {
2876         struct fib6_nh_rd_arg *arg = _arg;
2877
2878         arg->res->nh = nh;
2879         return ip6_redirect_nh_match(arg->res, arg->fl6, arg->gw, arg->ret);
2880 }
2881
2882 /* Handle redirects */
2883 struct ip6rd_flowi {
2884         struct flowi6 fl6;
2885         struct in6_addr gateway;
2886 };
2887
2888 static struct rt6_info *__ip6_route_redirect(struct net *net,
2889                                              struct fib6_table *table,
2890                                              struct flowi6 *fl6,
2891                                              const struct sk_buff *skb,
2892                                              int flags)
2893 {
2894         struct ip6rd_flowi *rdfl = (struct ip6rd_flowi *)fl6;
2895         struct rt6_info *ret = NULL;
2896         struct fib6_result res = {};
2897         struct fib6_nh_rd_arg arg = {
2898                 .res = &res,
2899                 .fl6 = fl6,
2900                 .gw  = &rdfl->gateway,
2901                 .ret = &ret
2902         };
2903         struct fib6_info *rt;
2904         struct fib6_node *fn;
2905
2906         /* l3mdev_update_flow overrides oif if the device is enslaved; in
2907          * this case we must match on the real ingress device, so reset it
2908          */
2909         if (fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF)
2910                 fl6->flowi6_oif = skb->dev->ifindex;
2911
2912         /* Get the "current" route for this destination and
2913          * check if the redirect has come from appropriate router.
2914          *
2915          * RFC 4861 specifies that redirects should only be
2916          * accepted if they come from the nexthop to the target.
2917          * Due to the way the routes are chosen, this notion
2918          * is a bit fuzzy and one might need to check all possible
2919          * routes.
2920          */
2921
2922         rcu_read_lock();
2923         fn = fib6_node_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
2924 restart:
2925         for_each_fib6_node_rt_rcu(fn) {
2926                 res.f6i = rt;
2927                 if (fib6_check_expired(rt))
2928                         continue;
2929                 if (rt->fib6_flags & RTF_REJECT)
2930                         break;
2931                 if (unlikely(rt->nh)) {
2932                         if (nexthop_is_blackhole(rt->nh))
2933                                 continue;
2934                         /* on match, res->nh is filled in and potentially ret */
2935                         if (nexthop_for_each_fib6_nh(rt->nh,
2936                                                      fib6_nh_redirect_match,
2937                                                      &arg))
2938                                 goto out;
2939                 } else {
2940                         res.nh = rt->fib6_nh;
2941                         if (ip6_redirect_nh_match(&res, fl6, &rdfl->gateway,
2942                                                   &ret))
2943                                 goto out;
2944                 }
2945         }
2946
2947         if (!rt)
2948                 rt = net->ipv6.fib6_null_entry;
2949         else if (rt->fib6_flags & RTF_REJECT) {
2950                 ret = net->ipv6.ip6_null_entry;
2951                 goto out;
2952         }
2953
2954         if (rt == net->ipv6.fib6_null_entry) {
2955                 fn = fib6_backtrack(fn, &fl6->saddr);
2956                 if (fn)
2957                         goto restart;
2958         }
2959
2960         res.f6i = rt;
2961         res.nh = rt->fib6_nh;
2962 out:
2963         if (ret) {
2964                 ip6_hold_safe(net, &ret);
2965         } else {
2966                 res.fib6_flags = res.f6i->fib6_flags;
2967                 res.fib6_type = res.f6i->fib6_type;
2968                 ret = ip6_create_rt_rcu(&res);
2969         }
2970
2971         rcu_read_unlock();
2972
2973         trace_fib6_table_lookup(net, &res, table, fl6);
2974         return ret;
2975 };
2976
2977 static struct dst_entry *ip6_route_redirect(struct net *net,
2978                                             const struct flowi6 *fl6,
2979                                             const struct sk_buff *skb,
2980                                             const struct in6_addr *gateway)
2981 {
2982         int flags = RT6_LOOKUP_F_HAS_SADDR;
2983         struct ip6rd_flowi rdfl;
2984
2985         rdfl.fl6 = *fl6;
2986         rdfl.gateway = *gateway;
2987
2988         return fib6_rule_lookup(net, &rdfl.fl6, skb,
2989                                 flags, __ip6_route_redirect);
2990 }
2991
2992 void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
2993                   kuid_t uid)
2994 {
2995         const struct ipv6hdr *iph = (struct ipv6hdr *) skb->data;
2996         struct dst_entry *dst;
2997         struct flowi6 fl6 = {
2998                 .flowi6_iif = LOOPBACK_IFINDEX,
2999                 .flowi6_oif = oif,
3000                 .flowi6_mark = mark,
3001                 .daddr = iph->daddr,
3002                 .saddr = iph->saddr,
3003                 .flowlabel = ip6_flowinfo(iph),
3004                 .flowi6_uid = uid,
3005         };
3006
3007         dst = ip6_route_redirect(net, &fl6, skb, &ipv6_hdr(skb)->saddr);
3008         rt6_do_redirect(dst, NULL, skb);
3009         dst_release(dst);
3010 }
3011 EXPORT_SYMBOL_GPL(ip6_redirect);
3012
3013 void ip6_redirect_no_header(struct sk_buff *skb, struct net *net, int oif)
3014 {
3015         const struct ipv6hdr *iph = ipv6_hdr(skb);
3016         const struct rd_msg *msg = (struct rd_msg *)icmp6_hdr(skb);
3017         struct dst_entry *dst;
3018         struct flowi6 fl6 = {
3019                 .flowi6_iif = LOOPBACK_IFINDEX,
3020                 .flowi6_oif = oif,
3021                 .daddr = msg->dest,
3022                 .saddr = iph->daddr,
3023                 .flowi6_uid = sock_net_uid(net, NULL),
3024         };
3025
3026         dst = ip6_route_redirect(net, &fl6, skb, &iph->saddr);
3027         rt6_do_redirect(dst, NULL, skb);
3028         dst_release(dst);
3029 }
3030
3031 void ip6_sk_redirect(struct sk_buff *skb, struct sock *sk)
3032 {
3033         ip6_redirect(skb, sock_net(sk), sk->sk_bound_dev_if, sk->sk_mark,
3034                      sk->sk_uid);
3035 }
3036 EXPORT_SYMBOL_GPL(ip6_sk_redirect);
3037
3038 static unsigned int ip6_default_advmss(const struct dst_entry *dst)
3039 {
3040         struct net_device *dev = dst->dev;
3041         unsigned int mtu = dst_mtu(dst);
3042         struct net *net = dev_net(dev);
3043
3044         mtu -= sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
3045
3046         if (mtu < net->ipv6.sysctl.ip6_rt_min_advmss)
3047                 mtu = net->ipv6.sysctl.ip6_rt_min_advmss;
3048
3049         /*
3050          * Maximal non-jumbo IPv6 payload is IPV6_MAXPLEN and
3051          * corresponding MSS is IPV6_MAXPLEN - tcp_header_size.
3052          * IPV6_MAXPLEN is also valid and means: "any MSS,
3053          * rely only on pmtu discovery"
3054          */
3055         if (mtu > IPV6_MAXPLEN - sizeof(struct tcphdr))
3056                 mtu = IPV6_MAXPLEN;
3057         return mtu;
3058 }
3059
3060 static unsigned int ip6_mtu(const struct dst_entry *dst)
3061 {
3062         struct inet6_dev *idev;
3063         unsigned int mtu;
3064
3065         mtu = dst_metric_raw(dst, RTAX_MTU);
3066         if (mtu)
3067                 goto out;
3068
3069         mtu = IPV6_MIN_MTU;
3070
3071         rcu_read_lock();
3072         idev = __in6_dev_get(dst->dev);
3073         if (idev)
3074                 mtu = idev->cnf.mtu6;
3075         rcu_read_unlock();
3076
3077 out:
3078         mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);
3079
3080         return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
3081 }
3082
3083 /* MTU selection:
3084  * 1. mtu on route is locked - use it
3085  * 2. mtu from nexthop exception
3086  * 3. mtu from egress device
3087  *
3088  * based on ip6_dst_mtu_forward and exception logic of
3089  * rt6_find_cached_rt; called with rcu_read_lock
3090  */
3091 u32 ip6_mtu_from_fib6(const struct fib6_result *res,
3092                       const struct in6_addr *daddr,
3093                       const struct in6_addr *saddr)
3094 {
3095         const struct fib6_nh *nh = res->nh;
3096         struct fib6_info *f6i = res->f6i;
3097         struct inet6_dev *idev;
3098         struct rt6_info *rt;
3099         u32 mtu = 0;
3100
3101         if (unlikely(fib6_metric_locked(f6i, RTAX_MTU))) {
3102                 mtu = f6i->fib6_pmtu;
3103                 if (mtu)
3104                         goto out;
3105         }
3106
3107         rt = rt6_find_cached_rt(res, daddr, saddr);
3108         if (unlikely(rt)) {
3109                 mtu = dst_metric_raw(&rt->dst, RTAX_MTU);
3110         } else {
3111                 struct net_device *dev = nh->fib_nh_dev;
3112
3113                 mtu = IPV6_MIN_MTU;
3114                 idev = __in6_dev_get(dev);
3115                 if (idev && idev->cnf.mtu6 > mtu)
3116                         mtu = idev->cnf.mtu6;
3117         }
3118
3119         mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);
3120 out:
3121         return mtu - lwtunnel_headroom(nh->fib_nh_lws, mtu);
3122 }
3123
3124 struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
3125                                   struct flowi6 *fl6)
3126 {
3127         struct dst_entry *dst;
3128         struct rt6_info *rt;
3129         struct inet6_dev *idev = in6_dev_get(dev);
3130         struct net *net = dev_net(dev);
3131
3132         if (unlikely(!idev))
3133                 return ERR_PTR(-ENODEV);
3134
3135         rt = ip6_dst_alloc(net, dev, 0);
3136         if (unlikely(!rt)) {
3137                 in6_dev_put(idev);
3138                 dst = ERR_PTR(-ENOMEM);
3139                 goto out;
3140         }
3141
3142         rt->dst.input = ip6_input;
3143         rt->dst.output  = ip6_output;
3144         rt->rt6i_gateway  = fl6->daddr;
3145         rt->rt6i_dst.addr = fl6->daddr;
3146         rt->rt6i_dst.plen = 128;
3147         rt->rt6i_idev     = idev;
3148         dst_metric_set(&rt->dst, RTAX_HOPLIMIT, 0);
3149
3150         /* Add this dst into uncached_list so that rt6_disable_ip() can
3151          * do proper release of the net_device
3152          */
3153         rt6_uncached_list_add(rt);
3154         atomic_inc(&net->ipv6.rt6_stats->fib_rt_uncache);
3155
3156         dst = xfrm_lookup(net, &rt->dst, flowi6_to_flowi(fl6), NULL, 0);
3157
3158 out:
3159         return dst;
3160 }
3161
3162 static int ip6_dst_gc(struct dst_ops *ops)
3163 {
3164         struct net *net = container_of(ops, struct net, ipv6.ip6_dst_ops);
3165         int rt_min_interval = net->ipv6.sysctl.ip6_rt_gc_min_interval;
3166         int rt_max_size = net->ipv6.sysctl.ip6_rt_max_size;
3167         int rt_elasticity = net->ipv6.sysctl.ip6_rt_gc_elasticity;
3168         int rt_gc_timeout = net->ipv6.sysctl.ip6_rt_gc_timeout;
3169         unsigned long rt_last_gc = net->ipv6.ip6_rt_last_gc;
3170         int entries;
3171
3172         entries = dst_entries_get_fast(ops);
3173         if (time_after(rt_last_gc + rt_min_interval, jiffies) &&
3174             entries <= rt_max_size)
3175                 goto out;
3176
3177         net->ipv6.ip6_rt_gc_expire++;
3178         fib6_run_gc(net->ipv6.ip6_rt_gc_expire, net, true);
3179         entries = dst_entries_get_slow(ops);
3180         if (entries < ops->gc_thresh)
3181                 net->ipv6.ip6_rt_gc_expire = rt_gc_timeout>>1;
3182 out:
3183         net->ipv6.ip6_rt_gc_expire -= net->ipv6.ip6_rt_gc_expire>>rt_elasticity;
3184         return entries > rt_max_size;
3185 }
3186
3187 static int ip6_nh_lookup_table(struct net *net, struct fib6_config *cfg,
3188                                const struct in6_addr *gw_addr, u32 tbid,
3189                                int flags, struct fib6_result *res)
3190 {
3191         struct flowi6 fl6 = {
3192                 .flowi6_oif = cfg->fc_ifindex,
3193                 .daddr = *gw_addr,
3194                 .saddr = cfg->fc_prefsrc,
3195         };
3196         struct fib6_table *table;
3197         int err;
3198
3199         table = fib6_get_table(net, tbid);
3200         if (!table)
3201                 return -EINVAL;
3202
3203         if (!ipv6_addr_any(&cfg->fc_prefsrc))
3204                 flags |= RT6_LOOKUP_F_HAS_SADDR;
3205
3206         flags |= RT6_LOOKUP_F_IGNORE_LINKSTATE;
3207
3208         err = fib6_table_lookup(net, table, cfg->fc_ifindex, &fl6, res, flags);
3209         if (!err && res->f6i != net->ipv6.fib6_null_entry)
3210                 fib6_select_path(net, res, &fl6, cfg->fc_ifindex,
3211                                  cfg->fc_ifindex != 0, NULL, flags);
3212
3213         return err;
3214 }
3215
3216 static int ip6_route_check_nh_onlink(struct net *net,
3217                                      struct fib6_config *cfg,
3218                                      const struct net_device *dev,
3219                                      struct netlink_ext_ack *extack)
3220 {
3221         u32 tbid = l3mdev_fib_table_rcu(dev) ? : RT_TABLE_MAIN;
3222         const struct in6_addr *gw_addr = &cfg->fc_gateway;
3223         struct fib6_result res = {};
3224         int err;
3225
3226         err = ip6_nh_lookup_table(net, cfg, gw_addr, tbid, 0, &res);
3227         if (!err && !(res.fib6_flags & RTF_REJECT) &&
3228             /* ignore match if it is the default route */
3229             !ipv6_addr_any(&res.f6i->fib6_dst.addr) &&
3230             (res.fib6_type != RTN_UNICAST || dev != res.nh->fib_nh_dev)) {
3231                 NL_SET_ERR_MSG(extack,
3232                                "Nexthop has invalid gateway or device mismatch");
3233                 err = -EINVAL;
3234         }
3235
3236         return err;
3237 }
3238
3239 static int ip6_route_check_nh(struct net *net,
3240                               struct fib6_config *cfg,
3241                               struct net_device **_dev,
3242                               struct inet6_dev **idev)
3243 {
3244         const struct in6_addr *gw_addr = &cfg->fc_gateway;
3245         struct net_device *dev = _dev ? *_dev : NULL;
3246         int flags = RT6_LOOKUP_F_IFACE;
3247         struct fib6_result res = {};
3248         int err = -EHOSTUNREACH;
3249
3250         if (cfg->fc_table) {
3251                 err = ip6_nh_lookup_table(net, cfg, gw_addr,
3252                                           cfg->fc_table, flags, &res);
3253                 /* gw_addr can not require a gateway or resolve to a reject
3254                  * route. If a device is given, it must match the result.
3255                  */
3256                 if (err || res.fib6_flags & RTF_REJECT ||
3257                     res.nh->fib_nh_gw_family ||
3258                     (dev && dev != res.nh->fib_nh_dev))
3259                         err = -EHOSTUNREACH;
3260         }
3261
3262         if (err < 0) {
3263                 struct flowi6 fl6 = {
3264                         .flowi6_oif = cfg->fc_ifindex,
3265                         .daddr = *gw_addr,
3266                 };
3267
3268                 err = fib6_lookup(net, cfg->fc_ifindex, &fl6, &res, flags);
3269                 if (err || res.fib6_flags & RTF_REJECT ||
3270                     res.nh->fib_nh_gw_family)
3271                         err = -EHOSTUNREACH;
3272
3273                 if (err)
3274                         return err;
3275
3276                 fib6_select_path(net, &res, &fl6, cfg->fc_ifindex,
3277                                  cfg->fc_ifindex != 0, NULL, flags);
3278         }
3279
3280         err = 0;
3281         if (dev) {
3282                 if (dev != res.nh->fib_nh_dev)
3283                         err = -EHOSTUNREACH;
3284         } else {
3285                 *_dev = dev = res.nh->fib_nh_dev;
3286                 dev_hold(dev);
3287                 *idev = in6_dev_get(dev);
3288         }
3289
3290         return err;
3291 }
3292
3293 static int ip6_validate_gw(struct net *net, struct fib6_config *cfg,
3294                            struct net_device **_dev, struct inet6_dev **idev,
3295                            struct netlink_ext_ack *extack)
3296 {
3297         const struct in6_addr *gw_addr = &cfg->fc_gateway;
3298         int gwa_type = ipv6_addr_type(gw_addr);
3299         bool skip_dev = gwa_type & IPV6_ADDR_LINKLOCAL ? false : true;
3300         const struct net_device *dev = *_dev;
3301         bool need_addr_check = !dev;
3302         int err = -EINVAL;
3303
3304         /* if gw_addr is local we will fail to detect this in case
3305          * address is still TENTATIVE (DAD in progress). rt6_lookup()
3306          * will return already-added prefix route via interface that
3307          * prefix route was assigned to, which might be non-loopback.
3308          */
3309         if (dev &&
3310             ipv6_chk_addr_and_flags(net, gw_addr, dev, skip_dev, 0, 0)) {
3311                 NL_SET_ERR_MSG(extack, "Gateway can not be a local address");
3312                 goto out;
3313         }
3314
3315         if (gwa_type != (IPV6_ADDR_LINKLOCAL | IPV6_ADDR_UNICAST)) {
3316                 /* IPv6 strictly inhibits using not link-local
3317                  * addresses as nexthop address.
3318                  * Otherwise, router will not able to send redirects.
3319                  * It is very good, but in some (rare!) circumstances
3320                  * (SIT, PtP, NBMA NOARP links) it is handy to allow
3321                  * some exceptions. --ANK
3322                  * We allow IPv4-mapped nexthops to support RFC4798-type
3323                  * addressing
3324                  */
3325                 if (!(gwa_type & (IPV6_ADDR_UNICAST | IPV6_ADDR_MAPPED))) {
3326                         NL_SET_ERR_MSG(extack, "Invalid gateway address");
3327                         goto out;
3328                 }
3329
3330                 rcu_read_lock();
3331
3332                 if (cfg->fc_flags & RTNH_F_ONLINK)
3333                         err = ip6_route_check_nh_onlink(net, cfg, dev, extack);
3334                 else
3335                         err = ip6_route_check_nh(net, cfg, _dev, idev);
3336
3337                 rcu_read_unlock();
3338
3339                 if (err)
3340                         goto out;
3341         }
3342
3343         /* reload in case device was changed */
3344         dev = *_dev;
3345
3346         err = -EINVAL;
3347         if (!dev) {
3348                 NL_SET_ERR_MSG(extack, "Egress device not specified");
3349                 goto out;
3350         } else if (dev->flags & IFF_LOOPBACK) {
3351                 NL_SET_ERR_MSG(extack,
3352                                "Egress device can not be loopback device for this route");
3353                 goto out;
3354         }
3355
3356         /* if we did not check gw_addr above, do so now that the
3357          * egress device has been resolved.
3358          */
3359         if (need_addr_check &&
3360             ipv6_chk_addr_and_flags(net, gw_addr, dev, skip_dev, 0, 0)) {
3361                 NL_SET_ERR_MSG(extack, "Gateway can not be a local address");
3362                 goto out;
3363         }
3364
3365         err = 0;
3366 out:
3367         return err;
3368 }
3369
3370 static bool fib6_is_reject(u32 flags, struct net_device *dev, int addr_type)
3371 {
3372         if ((flags & RTF_REJECT) ||
3373             (dev && (dev->flags & IFF_LOOPBACK) &&
3374              !(addr_type & IPV6_ADDR_LOOPBACK) &&
3375              !(flags & RTF_LOCAL)))
3376                 return true;
3377
3378         return false;
3379 }
3380
3381 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
3382                  struct fib6_config *cfg, gfp_t gfp_flags,
3383                  struct netlink_ext_ack *extack)
3384 {
3385         struct net_device *dev = NULL;
3386         struct inet6_dev *idev = NULL;
3387         int addr_type;
3388         int err;
3389
3390         fib6_nh->fib_nh_family = AF_INET6;
3391 #ifdef CONFIG_IPV6_ROUTER_PREF
3392         fib6_nh->last_probe = jiffies;
3393 #endif
3394
3395         err = -ENODEV;
3396         if (cfg->fc_ifindex) {
3397                 dev = dev_get_by_index(net, cfg->fc_ifindex);
3398                 if (!dev)
3399                         goto out;
3400                 idev = in6_dev_get(dev);
3401                 if (!idev)
3402                         goto out;
3403         }
3404
3405         if (cfg->fc_flags & RTNH_F_ONLINK) {
3406                 if (!dev) {
3407                         NL_SET_ERR_MSG(extack,
3408                                        "Nexthop device required for onlink");
3409                         goto out;
3410                 }
3411
3412                 if (!(dev->flags & IFF_UP)) {
3413                         NL_SET_ERR_MSG(extack, "Nexthop device is not up");
3414                         err = -ENETDOWN;
3415                         goto out;
3416                 }
3417
3418                 fib6_nh->fib_nh_flags |= RTNH_F_ONLINK;
3419         }
3420
3421         fib6_nh->fib_nh_weight = 1;
3422
3423         /* We cannot add true routes via loopback here,
3424          * they would result in kernel looping; promote them to reject routes
3425          */
3426         addr_type = ipv6_addr_type(&cfg->fc_dst);
3427         if (fib6_is_reject(cfg->fc_flags, dev, addr_type)) {
3428                 /* hold loopback dev/idev if we haven't done so. */
3429                 if (dev != net->loopback_dev) {
3430                         if (dev) {
3431                                 dev_put(dev);
3432                                 in6_dev_put(idev);
3433                         }
3434                         dev = net->loopback_dev;
3435                         dev_hold(dev);
3436                         idev = in6_dev_get(dev);
3437                         if (!idev) {
3438                                 err = -ENODEV;
3439                                 goto out;
3440                         }
3441                 }
3442                 goto pcpu_alloc;
3443         }
3444
3445         if (cfg->fc_flags & RTF_GATEWAY) {
3446                 err = ip6_validate_gw(net, cfg, &dev, &idev, extack);
3447                 if (err)
3448                         goto out;
3449
3450                 fib6_nh->fib_nh_gw6 = cfg->fc_gateway;
3451                 fib6_nh->fib_nh_gw_family = AF_INET6;
3452         }
3453
3454         err = -ENODEV;
3455         if (!dev)
3456                 goto out;
3457
3458         if (idev->cnf.disable_ipv6) {
3459                 NL_SET_ERR_MSG(extack, "IPv6 is disabled on nexthop device");
3460                 err = -EACCES;
3461                 goto out;
3462         }
3463
3464         if (!(dev->flags & IFF_UP) && !cfg->fc_ignore_dev_down) {
3465                 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
3466                 err = -ENETDOWN;
3467                 goto out;
3468         }
3469
3470         if (!(cfg->fc_flags & (RTF_LOCAL | RTF_ANYCAST)) &&
3471             !netif_carrier_ok(dev))
3472                 fib6_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
3473
3474         err = fib_nh_common_init(net, &fib6_nh->nh_common, cfg->fc_encap,
3475                                  cfg->fc_encap_type, cfg, gfp_flags, extack);
3476         if (err)
3477                 goto out;
3478
3479 pcpu_alloc:
3480         fib6_nh->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
3481         if (!fib6_nh->rt6i_pcpu) {
3482                 err = -ENOMEM;
3483                 goto out;
3484         }
3485
3486         fib6_nh->fib_nh_dev = dev;
3487         fib6_nh->fib_nh_oif = dev->ifindex;
3488         err = 0;
3489 out:
3490         if (idev)
3491                 in6_dev_put(idev);
3492
3493         if (err) {
3494                 lwtstate_put(fib6_nh->fib_nh_lws);
3495                 fib6_nh->fib_nh_lws = NULL;
3496                 if (dev)
3497                         dev_put(dev);
3498         }
3499
3500         return err;
3501 }
3502
3503 void fib6_nh_release(struct fib6_nh *fib6_nh)
3504 {
3505         struct rt6_exception_bucket *bucket;
3506
3507         rcu_read_lock();
3508
3509         fib6_nh_flush_exceptions(fib6_nh, NULL);
3510         bucket = fib6_nh_get_excptn_bucket(fib6_nh, NULL);
3511         if (bucket) {
3512                 rcu_assign_pointer(fib6_nh->rt6i_exception_bucket, NULL);
3513                 kfree(bucket);
3514         }
3515
3516         rcu_read_unlock();
3517
3518         if (fib6_nh->rt6i_pcpu) {
3519                 int cpu;
3520
3521                 for_each_possible_cpu(cpu) {
3522                         struct rt6_info **ppcpu_rt;
3523                         struct rt6_info *pcpu_rt;
3524
3525                         ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
3526                         pcpu_rt = *ppcpu_rt;
3527                         if (pcpu_rt) {
3528                                 dst_dev_put(&pcpu_rt->dst);
3529                                 dst_release(&pcpu_rt->dst);
3530                                 *ppcpu_rt = NULL;
3531                         }
3532                 }
3533
3534                 free_percpu(fib6_nh->rt6i_pcpu);
3535         }
3536
3537         fib_nh_common_release(&fib6_nh->nh_common);
3538 }
3539
3540 static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
3541                                               gfp_t gfp_flags,
3542                                               struct netlink_ext_ack *extack)
3543 {
3544         struct net *net = cfg->fc_nlinfo.nl_net;
3545         struct fib6_info *rt = NULL;
3546         struct nexthop *nh = NULL;
3547         struct fib6_table *table;
3548         struct fib6_nh *fib6_nh;
3549         int err = -EINVAL;
3550         int addr_type;
3551
3552         /* RTF_PCPU is an internal flag; can not be set by userspace */
3553         if (cfg->fc_flags & RTF_PCPU) {
3554                 NL_SET_ERR_MSG(extack, "Userspace can not set RTF_PCPU");
3555                 goto out;
3556         }
3557
3558         /* RTF_CACHE is an internal flag; can not be set by userspace */
3559         if (cfg->fc_flags & RTF_CACHE) {
3560                 NL_SET_ERR_MSG(extack, "Userspace can not set RTF_CACHE");
3561                 goto out;
3562         }
3563
3564         if (cfg->fc_type > RTN_MAX) {
3565                 NL_SET_ERR_MSG(extack, "Invalid route type");
3566                 goto out;
3567         }
3568
3569         if (cfg->fc_dst_len > 128) {
3570                 NL_SET_ERR_MSG(extack, "Invalid prefix length");
3571                 goto out;
3572         }
3573         if (cfg->fc_src_len > 128) {
3574                 NL_SET_ERR_MSG(extack, "Invalid source address length");
3575                 goto out;
3576         }
3577 #ifndef CONFIG_IPV6_SUBTREES
3578         if (cfg->fc_src_len) {
3579                 NL_SET_ERR_MSG(extack,
3580                                "Specifying source address requires IPV6_SUBTREES to be enabled");
3581                 goto out;
3582         }
3583 #endif
3584         if (cfg->fc_nh_id) {
3585                 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
3586                 if (!nh) {
3587                         NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
3588                         goto out;
3589                 }
3590                 err = fib6_check_nexthop(nh, cfg, extack);
3591                 if (err)
3592                         goto out;
3593         }
3594
3595         err = -ENOBUFS;
3596         if (cfg->fc_nlinfo.nlh &&
3597             !(cfg->fc_nlinfo.nlh->nlmsg_flags & NLM_F_CREATE)) {
3598                 table = fib6_get_table(net, cfg->fc_table);
3599                 if (!table) {
3600                         pr_warn("NLM_F_CREATE should be specified when creating new route\n");
3601                         table = fib6_new_table(net, cfg->fc_table);
3602                 }
3603         } else {
3604                 table = fib6_new_table(net, cfg->fc_table);
3605         }
3606
3607         if (!table)
3608                 goto out;
3609
3610         err = -ENOMEM;
3611         rt = fib6_info_alloc(gfp_flags, !nh);
3612         if (!rt)
3613                 goto out;
3614
3615         rt->fib6_metrics = ip_fib_metrics_init(net, cfg->fc_mx, cfg->fc_mx_len,
3616                                                extack);
3617         if (IS_ERR(rt->fib6_metrics)) {
3618                 err = PTR_ERR(rt->fib6_metrics);
3619                 /* Do not leave garbage there. */
3620                 rt->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
3621                 goto out;
3622         }
3623
3624         if (cfg->fc_flags & RTF_ADDRCONF)
3625                 rt->dst_nocount = true;
3626
3627         if (cfg->fc_flags & RTF_EXPIRES)
3628                 fib6_set_expires(rt, jiffies +
3629                                 clock_t_to_jiffies(cfg->fc_expires));
3630         else
3631                 fib6_clean_expires(rt);
3632
3633         if (cfg->fc_protocol == RTPROT_UNSPEC)
3634                 cfg->fc_protocol = RTPROT_BOOT;
3635         rt->fib6_protocol = cfg->fc_protocol;
3636
3637         rt->fib6_table = table;
3638         rt->fib6_metric = cfg->fc_metric;
3639         rt->fib6_type = cfg->fc_type ? : RTN_UNICAST;
3640         rt->fib6_flags = cfg->fc_flags & ~RTF_GATEWAY;
3641
3642         ipv6_addr_prefix(&rt->fib6_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);
3643         rt->fib6_dst.plen = cfg->fc_dst_len;
3644
3645 #ifdef CONFIG_IPV6_SUBTREES
3646         ipv6_addr_prefix(&rt->fib6_src.addr, &cfg->fc_src, cfg->fc_src_len);
3647         rt->fib6_src.plen = cfg->fc_src_len;
3648 #endif
3649         if (nh) {
3650                 if (!nexthop_get(nh)) {
3651                         NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
3652                         goto out;
3653                 }
3654                 if (rt->fib6_src.plen) {
3655                         NL_SET_ERR_MSG(extack, "Nexthops can not be used with source routing");
3656                         goto out;
3657                 }
3658                 rt->nh = nh;
3659                 fib6_nh = nexthop_fib6_nh(rt->nh);
3660         } else {
3661                 err = fib6_nh_init(net, rt->fib6_nh, cfg, gfp_flags, extack);
3662                 if (err)
3663                         goto out;
3664
3665                 fib6_nh = rt->fib6_nh;
3666
3667                 /* We cannot add true routes via loopback here, they would
3668                  * result in kernel looping; promote them to reject routes
3669                  */
3670                 addr_type = ipv6_addr_type(&cfg->fc_dst);
3671                 if (fib6_is_reject(cfg->fc_flags, rt->fib6_nh->fib_nh_dev,
3672                                    addr_type))
3673                         rt->fib6_flags = RTF_REJECT | RTF_NONEXTHOP;
3674         }
3675
3676         if (!ipv6_addr_any(&cfg->fc_prefsrc)) {
3677                 struct net_device *dev = fib6_nh->fib_nh_dev;
3678
3679                 if (!ipv6_chk_addr(net, &cfg->fc_prefsrc, dev, 0)) {
3680                         NL_SET_ERR_MSG(extack, "Invalid source address");
3681                         err = -EINVAL;
3682                         goto out;
3683                 }
3684                 rt->fib6_prefsrc.addr = cfg->fc_prefsrc;
3685                 rt->fib6_prefsrc.plen = 128;
3686         } else
3687                 rt->fib6_prefsrc.plen = 0;
3688
3689         return rt;
3690 out:
3691         fib6_info_release(rt);
3692         return ERR_PTR(err);
3693 }
3694
3695 int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags,
3696                   struct netlink_ext_ack *extack)
3697 {
3698         struct fib6_info *rt;
3699         int err;
3700
3701         rt = ip6_route_info_create(cfg, gfp_flags, extack);
3702         if (IS_ERR(rt))
3703                 return PTR_ERR(rt);
3704
3705         err = __ip6_ins_rt(rt, &cfg->fc_nlinfo, extack);
3706         fib6_info_release(rt);
3707
3708         return err;
3709 }
3710
3711 static int __ip6_del_rt(struct fib6_info *rt, struct nl_info *info)
3712 {
3713         struct net *net = info->nl_net;
3714         struct fib6_table *table;
3715         int err;
3716
3717         if (rt == net->ipv6.fib6_null_entry) {
3718                 err = -ENOENT;
3719                 goto out;
3720         }
3721
3722         table = rt->fib6_table;
3723         spin_lock_bh(&table->tb6_lock);
3724         err = fib6_del(rt, info);
3725         spin_unlock_bh(&table->tb6_lock);
3726
3727 out:
3728         fib6_info_release(rt);
3729         return err;
3730 }
3731
3732 int ip6_del_rt(struct net *net, struct fib6_info *rt, bool skip_notify)
3733 {
3734         struct nl_info info = {
3735                 .nl_net = net,
3736                 .skip_notify = skip_notify
3737         };
3738
3739         return __ip6_del_rt(rt, &info);
3740 }
3741
3742 static int __ip6_del_rt_siblings(struct fib6_info *rt, struct fib6_config *cfg)
3743 {
3744         struct nl_info *info = &cfg->fc_nlinfo;
3745         struct net *net = info->nl_net;
3746         struct sk_buff *skb = NULL;
3747         struct fib6_table *table;
3748         int err = -ENOENT;
3749
3750         if (rt == net->ipv6.fib6_null_entry)
3751                 goto out_put;
3752         table = rt->fib6_table;
3753         spin_lock_bh(&table->tb6_lock);
3754
3755         if (rt->fib6_nsiblings && cfg->fc_delete_all_nh) {
3756                 struct fib6_info *sibling, *next_sibling;
3757                 struct fib6_node *fn;
3758
3759                 /* prefer to send a single notification with all hops */
3760                 skb = nlmsg_new(rt6_nlmsg_size(rt), gfp_any());
3761                 if (skb) {
3762                         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
3763
3764                         if (rt6_fill_node(net, skb, rt, NULL,
3765                                           NULL, NULL, 0, RTM_DELROUTE,
3766                                           info->portid, seq, 0) < 0) {
3767                                 kfree_skb(skb);
3768                                 skb = NULL;
3769                         } else
3770                                 info->skip_notify = 1;
3771                 }
3772
3773                 /* 'rt' points to the first sibling route. If it is not the
3774                  * leaf, then we do not need to send a notification. Otherwise,
3775                  * we need to check if the last sibling has a next route or not
3776                  * and emit a replace or delete notification, respectively.
3777                  */
3778                 info->skip_notify_kernel = 1;
3779                 fn = rcu_dereference_protected(rt->fib6_node,
3780                                             lockdep_is_held(&table->tb6_lock));
3781                 if (rcu_access_pointer(fn->leaf) == rt) {
3782                         struct fib6_info *last_sibling, *replace_rt;
3783
3784                         last_sibling = list_last_entry(&rt->fib6_siblings,
3785                                                        struct fib6_info,
3786                                                        fib6_siblings);
3787                         replace_rt = rcu_dereference_protected(
3788                                             last_sibling->fib6_next,
3789                                             lockdep_is_held(&table->tb6_lock));
3790                         if (replace_rt)
3791                                 call_fib6_entry_notifiers_replace(net,
3792                                                                   replace_rt);
3793                         else
3794                                 call_fib6_multipath_entry_notifiers(net,
3795                                                        FIB_EVENT_ENTRY_DEL,
3796                                                        rt, rt->fib6_nsiblings,
3797                                                        NULL);
3798                 }
3799                 list_for_each_entry_safe(sibling, next_sibling,
3800                                          &rt->fib6_siblings,
3801                                          fib6_siblings) {
3802                         err = fib6_del(sibling, info);
3803                         if (err)
3804                                 goto out_unlock;
3805                 }
3806         }
3807
3808         err = fib6_del(rt, info);
3809 out_unlock:
3810         spin_unlock_bh(&table->tb6_lock);
3811 out_put:
3812         fib6_info_release(rt);
3813
3814         if (skb) {
3815                 rtnl_notify(skb, net, info->portid, RTNLGRP_IPV6_ROUTE,
3816                             info->nlh, gfp_any());
3817         }
3818         return err;
3819 }
3820
3821 static int __ip6_del_cached_rt(struct rt6_info *rt, struct fib6_config *cfg)
3822 {
3823         int rc = -ESRCH;
3824
3825         if (cfg->fc_ifindex && rt->dst.dev->ifindex != cfg->fc_ifindex)
3826                 goto out;
3827
3828         if (cfg->fc_flags & RTF_GATEWAY &&
3829             !ipv6_addr_equal(&cfg->fc_gateway, &rt->rt6i_gateway))
3830                 goto out;
3831
3832         rc = rt6_remove_exception_rt(rt);
3833 out:
3834         return rc;
3835 }
3836
3837 static int ip6_del_cached_rt(struct fib6_config *cfg, struct fib6_info *rt,
3838                              struct fib6_nh *nh)
3839 {
3840         struct fib6_result res = {
3841                 .f6i = rt,
3842                 .nh = nh,
3843         };
3844         struct rt6_info *rt_cache;
3845
3846         rt_cache = rt6_find_cached_rt(&res, &cfg->fc_dst, &cfg->fc_src);
3847         if (rt_cache)
3848                 return __ip6_del_cached_rt(rt_cache, cfg);
3849
3850         return 0;
3851 }
3852
3853 struct fib6_nh_del_cached_rt_arg {
3854         struct fib6_config *cfg;
3855         struct fib6_info *f6i;
3856 };
3857
3858 static int fib6_nh_del_cached_rt(struct fib6_nh *nh, void *_arg)
3859 {
3860         struct fib6_nh_del_cached_rt_arg *arg = _arg;
3861         int rc;
3862
3863         rc = ip6_del_cached_rt(arg->cfg, arg->f6i, nh);
3864         return rc != -ESRCH ? rc : 0;
3865 }
3866
3867 static int ip6_del_cached_rt_nh(struct fib6_config *cfg, struct fib6_info *f6i)
3868 {
3869         struct fib6_nh_del_cached_rt_arg arg = {
3870                 .cfg = cfg,
3871                 .f6i = f6i
3872         };
3873
3874         return nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_del_cached_rt, &arg);
3875 }
3876
3877 static int ip6_route_del(struct fib6_config *cfg,
3878                          struct netlink_ext_ack *extack)
3879 {
3880         struct fib6_table *table;
3881         struct fib6_info *rt;
3882         struct fib6_node *fn;
3883         int err = -ESRCH;
3884
3885         table = fib6_get_table(cfg->fc_nlinfo.nl_net, cfg->fc_table);
3886         if (!table) {
3887                 NL_SET_ERR_MSG(extack, "FIB table does not exist");
3888                 return err;
3889         }
3890
3891         rcu_read_lock();
3892
3893         fn = fib6_locate(&table->tb6_root,
3894                          &cfg->fc_dst, cfg->fc_dst_len,
3895                          &cfg->fc_src, cfg->fc_src_len,
3896                          !(cfg->fc_flags & RTF_CACHE));
3897
3898         if (fn) {
3899                 for_each_fib6_node_rt_rcu(fn) {
3900                         struct fib6_nh *nh;
3901
3902                         if (rt->nh && cfg->fc_nh_id &&
3903                             rt->nh->id != cfg->fc_nh_id)
3904                                 continue;
3905
3906                         if (cfg->fc_flags & RTF_CACHE) {
3907                                 int rc = 0;
3908
3909                                 if (rt->nh) {
3910                                         rc = ip6_del_cached_rt_nh(cfg, rt);
3911                                 } else if (cfg->fc_nh_id) {
3912                                         continue;
3913                                 } else {
3914                                         nh = rt->fib6_nh;
3915                                         rc = ip6_del_cached_rt(cfg, rt, nh);
3916                                 }
3917                                 if (rc != -ESRCH) {
3918                                         rcu_read_unlock();
3919                                         return rc;
3920                                 }
3921                                 continue;
3922                         }
3923
3924                         if (cfg->fc_metric && cfg->fc_metric != rt->fib6_metric)
3925                                 continue;
3926                         if (cfg->fc_protocol &&
3927                             cfg->fc_protocol != rt->fib6_protocol)
3928                                 continue;
3929
3930                         if (rt->nh) {
3931                                 if (!fib6_info_hold_safe(rt))
3932                                         continue;
3933                                 rcu_read_unlock();
3934
3935                                 return __ip6_del_rt(rt, &cfg->fc_nlinfo);
3936                         }
3937                         if (cfg->fc_nh_id)
3938                                 continue;
3939
3940                         nh = rt->fib6_nh;
3941                         if (cfg->fc_ifindex &&
3942                             (!nh->fib_nh_dev ||
3943                              nh->fib_nh_dev->ifindex != cfg->fc_ifindex))
3944                                 continue;
3945                         if (cfg->fc_flags & RTF_GATEWAY &&
3946                             !ipv6_addr_equal(&cfg->fc_gateway, &nh->fib_nh_gw6))
3947                                 continue;
3948                         if (!fib6_info_hold_safe(rt))
3949                                 continue;
3950                         rcu_read_unlock();
3951
3952                         /* if gateway was specified only delete the one hop */
3953                         if (cfg->fc_flags & RTF_GATEWAY)
3954                                 return __ip6_del_rt(rt, &cfg->fc_nlinfo);
3955
3956                         return __ip6_del_rt_siblings(rt, cfg);
3957                 }
3958         }
3959         rcu_read_unlock();
3960
3961         return err;
3962 }
3963
3964 static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
3965 {
3966         struct netevent_redirect netevent;
3967         struct rt6_info *rt, *nrt = NULL;
3968         struct fib6_result res = {};
3969         struct ndisc_options ndopts;
3970         struct inet6_dev *in6_dev;
3971         struct neighbour *neigh;
3972         struct rd_msg *msg;
3973         int optlen, on_link;
3974         u8 *lladdr;
3975
3976         optlen = skb_tail_pointer(skb) - skb_transport_header(skb);
3977         optlen -= sizeof(*msg);
3978
3979         if (optlen < 0) {
3980                 net_dbg_ratelimited("rt6_do_redirect: packet too short\n");
3981                 return;
3982         }
3983
3984         msg = (struct rd_msg *)icmp6_hdr(skb);
3985
3986         if (ipv6_addr_is_multicast(&msg->dest)) {
3987                 net_dbg_ratelimited("rt6_do_redirect: destination address is multicast\n");
3988                 return;
3989         }
3990
3991         on_link = 0;
3992         if (ipv6_addr_equal(&msg->dest, &msg->target)) {
3993                 on_link = 1;
3994         } else if (ipv6_addr_type(&msg->target) !=
3995                    (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
3996                 net_dbg_ratelimited("rt6_do_redirect: target address is not link-local unicast\n");
3997                 return;
3998         }
3999
4000         in6_dev = __in6_dev_get(skb->dev);
4001         if (!in6_dev)
4002                 return;
4003         if (in6_dev->cnf.forwarding || !in6_dev->cnf.accept_redirects)
4004                 return;
4005
4006         /* RFC2461 8.1:
4007          *      The IP source address of the Redirect MUST be the same as the current
4008          *      first-hop router for the specified ICMP Destination Address.
4009          */
4010
4011         if (!ndisc_parse_options(skb->dev, msg->opt, optlen, &ndopts)) {
4012                 net_dbg_ratelimited("rt6_redirect: invalid ND options\n");
4013                 return;
4014         }
4015
4016         lladdr = NULL;
4017         if (ndopts.nd_opts_tgt_lladdr) {
4018                 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr,
4019                                              skb->dev);
4020                 if (!lladdr) {
4021                         net_dbg_ratelimited("rt6_redirect: invalid link-layer address length\n");
4022                         return;
4023                 }
4024         }
4025
4026         rt = (struct rt6_info *) dst;
4027         if (rt->rt6i_flags & RTF_REJECT) {
4028                 net_dbg_ratelimited("rt6_redirect: source isn't a valid nexthop for redirect target\n");
4029                 return;
4030         }
4031
4032         /* Redirect received -> path was valid.
4033          * Look, redirects are sent only in response to data packets,
4034          * so that this nexthop apparently is reachable. --ANK
4035          */
4036         dst_confirm_neigh(&rt->dst, &ipv6_hdr(skb)->saddr);
4037
4038         neigh = __neigh_lookup(&nd_tbl, &msg->target, skb->dev, 1);
4039         if (!neigh)
4040                 return;
4041
4042         /*
4043          *      We have finally decided to accept it.
4044          */
4045
4046         ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
4047                      NEIGH_UPDATE_F_WEAK_OVERRIDE|
4048                      NEIGH_UPDATE_F_OVERRIDE|
4049                      (on_link ? 0 : (NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
4050                                      NEIGH_UPDATE_F_ISROUTER)),
4051                      NDISC_REDIRECT, &ndopts);
4052
4053         rcu_read_lock();
4054         res.f6i = rcu_dereference(rt->from);
4055         if (!res.f6i)
4056                 goto out;
4057
4058         if (res.f6i->nh) {
4059                 struct fib6_nh_match_arg arg = {
4060                         .dev = dst->dev,
4061                         .gw = &rt->rt6i_gateway,
4062                 };
4063
4064                 nexthop_for_each_fib6_nh(res.f6i->nh,
4065                                          fib6_nh_find_match, &arg);
4066
4067                 /* fib6_info uses a nexthop that does not have fib6_nh
4068                  * using the dst->dev. Should be impossible
4069                  */
4070                 if (!arg.match)
4071                         goto out;
4072                 res.nh = arg.match;
4073         } else {
4074                 res.nh = res.f6i->fib6_nh;
4075         }
4076
4077         res.fib6_flags = res.f6i->fib6_flags;
4078         res.fib6_type = res.f6i->fib6_type;
4079         nrt = ip6_rt_cache_alloc(&res, &msg->dest, NULL);
4080         if (!nrt)
4081                 goto out;
4082
4083         nrt->rt6i_flags = RTF_GATEWAY|RTF_UP|RTF_DYNAMIC|RTF_CACHE;
4084         if (on_link)
4085                 nrt->rt6i_flags &= ~RTF_GATEWAY;
4086
4087         nrt->rt6i_gateway = *(struct in6_addr *)neigh->primary_key;
4088
4089         /* rt6_insert_exception() will take care of duplicated exceptions */
4090         if (rt6_insert_exception(nrt, &res)) {
4091                 dst_release_immediate(&nrt->dst);
4092                 goto out;
4093         }
4094
4095         netevent.old = &rt->dst;
4096         netevent.new = &nrt->dst;
4097         netevent.daddr = &msg->dest;
4098         netevent.neigh = neigh;
4099         call_netevent_notifiers(NETEVENT_REDIRECT, &netevent);
4100
4101 out:
4102         rcu_read_unlock();
4103         neigh_release(neigh);
4104 }
4105
4106 #ifdef CONFIG_IPV6_ROUTE_INFO
4107 static struct fib6_info *rt6_get_route_info(struct net *net,
4108                                            const struct in6_addr *prefix, int prefixlen,
4109                                            const struct in6_addr *gwaddr,
4110                                            struct net_device *dev)
4111 {
4112         u32 tb_id = l3mdev_fib_table(dev) ? : RT6_TABLE_INFO;
4113         int ifindex = dev->ifindex;
4114         struct fib6_node *fn;
4115         struct fib6_info *rt = NULL;
4116         struct fib6_table *table;
4117
4118         table = fib6_get_table(net, tb_id);
4119         if (!table)
4120                 return NULL;
4121
4122         rcu_read_lock();
4123         fn = fib6_locate(&table->tb6_root, prefix, prefixlen, NULL, 0, true);
4124         if (!fn)
4125                 goto out;
4126
4127         for_each_fib6_node_rt_rcu(fn) {
4128                 /* these routes do not use nexthops */
4129                 if (rt->nh)
4130                         continue;
4131                 if (rt->fib6_nh->fib_nh_dev->ifindex != ifindex)
4132                         continue;
4133                 if (!(rt->fib6_flags & RTF_ROUTEINFO) ||
4134                     !rt->fib6_nh->fib_nh_gw_family)
4135                         continue;
4136                 if (!ipv6_addr_equal(&rt->fib6_nh->fib_nh_gw6, gwaddr))
4137                         continue;
4138                 if (!fib6_info_hold_safe(rt))
4139                         continue;
4140                 break;
4141         }
4142 out:
4143         rcu_read_unlock();
4144         return rt;
4145 }
4146
4147 static struct fib6_info *rt6_add_route_info(struct net *net,
4148                                            const struct in6_addr *prefix, int prefixlen,
4149                                            const struct in6_addr *gwaddr,
4150                                            struct net_device *dev,
4151                                            unsigned int pref)
4152 {
4153         struct fib6_config cfg = {
4154                 .fc_metric      = IP6_RT_PRIO_USER,
4155                 .fc_ifindex     = dev->ifindex,
4156                 .fc_dst_len     = prefixlen,
4157                 .fc_flags       = RTF_GATEWAY | RTF_ADDRCONF | RTF_ROUTEINFO |
4158                                   RTF_UP | RTF_PREF(pref),
4159                 .fc_protocol = RTPROT_RA,
4160                 .fc_type = RTN_UNICAST,
4161                 .fc_nlinfo.portid = 0,
4162                 .fc_nlinfo.nlh = NULL,
4163                 .fc_nlinfo.nl_net = net,
4164         };
4165
4166         cfg.fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_INFO,
4167         cfg.fc_dst = *prefix;
4168         cfg.fc_gateway = *gwaddr;
4169
4170         /* We should treat it as a default route if prefix length is 0. */
4171         if (!prefixlen)
4172                 cfg.fc_flags |= RTF_DEFAULT;
4173
4174         ip6_route_add(&cfg, GFP_ATOMIC, NULL);
4175
4176         return rt6_get_route_info(net, prefix, prefixlen, gwaddr, dev);
4177 }
4178 #endif
4179
4180 struct fib6_info *rt6_get_dflt_router(struct net *net,
4181                                      const struct in6_addr *addr,
4182                                      struct net_device *dev)
4183 {
4184         u32 tb_id = l3mdev_fib_table(dev) ? : RT6_TABLE_DFLT;
4185         struct fib6_info *rt;
4186         struct fib6_table *table;
4187
4188         table = fib6_get_table(net, tb_id);
4189         if (!table)
4190                 return NULL;
4191
4192         rcu_read_lock();
4193         for_each_fib6_node_rt_rcu(&table->tb6_root) {
4194                 struct fib6_nh *nh;
4195
4196                 /* RA routes do not use nexthops */
4197                 if (rt->nh)
4198                         continue;
4199
4200                 nh = rt->fib6_nh;
4201                 if (dev == nh->fib_nh_dev &&
4202                     ((rt->fib6_flags & (RTF_ADDRCONF | RTF_DEFAULT)) == (RTF_ADDRCONF | RTF_DEFAULT)) &&
4203                     ipv6_addr_equal(&nh->fib_nh_gw6, addr))
4204                         break;
4205         }
4206         if (rt && !fib6_info_hold_safe(rt))
4207                 rt = NULL;
4208         rcu_read_unlock();
4209         return rt;
4210 }
4211
4212 struct fib6_info *rt6_add_dflt_router(struct net *net,
4213                                      const struct in6_addr *gwaddr,
4214                                      struct net_device *dev,
4215                                      unsigned int pref)
4216 {
4217         struct fib6_config cfg = {
4218                 .fc_table       = l3mdev_fib_table(dev) ? : RT6_TABLE_DFLT,
4219                 .fc_metric      = IP6_RT_PRIO_USER,
4220                 .fc_ifindex     = dev->ifindex,
4221                 .fc_flags       = RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT |
4222                                   RTF_UP | RTF_EXPIRES | RTF_PREF(pref),
4223                 .fc_protocol = RTPROT_RA,
4224                 .fc_type = RTN_UNICAST,
4225                 .fc_nlinfo.portid = 0,
4226                 .fc_nlinfo.nlh = NULL,
4227                 .fc_nlinfo.nl_net = net,
4228         };
4229
4230         cfg.fc_gateway = *gwaddr;
4231
4232         if (!ip6_route_add(&cfg, GFP_ATOMIC, NULL)) {
4233                 struct fib6_table *table;
4234
4235                 table = fib6_get_table(dev_net(dev), cfg.fc_table);
4236                 if (table)
4237                         table->flags |= RT6_TABLE_HAS_DFLT_ROUTER;
4238         }
4239
4240         return rt6_get_dflt_router(net, gwaddr, dev);
4241 }
4242
4243 static void __rt6_purge_dflt_routers(struct net *net,
4244                                      struct fib6_table *table)
4245 {
4246         struct fib6_info *rt;
4247
4248 restart:
4249         rcu_read_lock();
4250         for_each_fib6_node_rt_rcu(&table->tb6_root) {
4251                 struct net_device *dev = fib6_info_nh_dev(rt);
4252                 struct inet6_dev *idev = dev ? __in6_dev_get(dev) : NULL;
4253
4254                 if (rt->fib6_flags & (RTF_DEFAULT | RTF_ADDRCONF) &&
4255                     (!idev || idev->cnf.accept_ra != 2) &&
4256                     fib6_info_hold_safe(rt)) {
4257                         rcu_read_unlock();
4258                         ip6_del_rt(net, rt, false);
4259                         goto restart;
4260                 }
4261         }
4262         rcu_read_unlock();
4263
4264         table->flags &= ~RT6_TABLE_HAS_DFLT_ROUTER;
4265 }
4266
4267 void rt6_purge_dflt_routers(struct net *net)
4268 {
4269         struct fib6_table *table;
4270         struct hlist_head *head;
4271         unsigned int h;
4272
4273         rcu_read_lock();
4274
4275         for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
4276                 head = &net->ipv6.fib_table_hash[h];
4277                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
4278                         if (table->flags & RT6_TABLE_HAS_DFLT_ROUTER)
4279                                 __rt6_purge_dflt_routers(net, table);
4280                 }
4281         }
4282
4283         rcu_read_unlock();
4284 }
4285
4286 static void rtmsg_to_fib6_config(struct net *net,
4287                                  struct in6_rtmsg *rtmsg,
4288                                  struct fib6_config *cfg)
4289 {
4290         *cfg = (struct fib6_config){
4291                 .fc_table = l3mdev_fib_table_by_index(net, rtmsg->rtmsg_ifindex) ?
4292                          : RT6_TABLE_MAIN,
4293                 .fc_ifindex = rtmsg->rtmsg_ifindex,
4294                 .fc_metric = rtmsg->rtmsg_metric ? : IP6_RT_PRIO_USER,
4295                 .fc_expires = rtmsg->rtmsg_info,
4296                 .fc_dst_len = rtmsg->rtmsg_dst_len,
4297                 .fc_src_len = rtmsg->rtmsg_src_len,
4298                 .fc_flags = rtmsg->rtmsg_flags,
4299                 .fc_type = rtmsg->rtmsg_type,
4300
4301                 .fc_nlinfo.nl_net = net,
4302
4303                 .fc_dst = rtmsg->rtmsg_dst,
4304                 .fc_src = rtmsg->rtmsg_src,
4305                 .fc_gateway = rtmsg->rtmsg_gateway,
4306         };
4307 }
4308
4309 int ipv6_route_ioctl(struct net *net, unsigned int cmd, void __user *arg)
4310 {
4311         struct fib6_config cfg;
4312         struct in6_rtmsg rtmsg;
4313         int err;
4314
4315         switch (cmd) {
4316         case SIOCADDRT:         /* Add a route */
4317         case SIOCDELRT:         /* Delete a route */
4318                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
4319                         return -EPERM;
4320                 err = copy_from_user(&rtmsg, arg,
4321                                      sizeof(struct in6_rtmsg));
4322                 if (err)
4323                         return -EFAULT;
4324
4325                 rtmsg_to_fib6_config(net, &rtmsg, &cfg);
4326
4327                 rtnl_lock();
4328                 switch (cmd) {
4329                 case SIOCADDRT:
4330                         err = ip6_route_add(&cfg, GFP_KERNEL, NULL);
4331                         break;
4332                 case SIOCDELRT:
4333                         err = ip6_route_del(&cfg, NULL);
4334                         break;
4335                 default:
4336                         err = -EINVAL;
4337                 }
4338                 rtnl_unlock();
4339
4340                 return err;
4341         }
4342
4343         return -EINVAL;
4344 }
4345
4346 /*
4347  *      Drop the packet on the floor
4348  */
4349
4350 static int ip6_pkt_drop(struct sk_buff *skb, u8 code, int ipstats_mib_noroutes)
4351 {
4352         struct dst_entry *dst = skb_dst(skb);
4353         struct net *net = dev_net(dst->dev);
4354         struct inet6_dev *idev;
4355         int type;
4356
4357         if (netif_is_l3_master(skb->dev) &&
4358             dst->dev == net->loopback_dev)
4359                 idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
4360         else
4361                 idev = ip6_dst_idev(dst);
4362
4363         switch (ipstats_mib_noroutes) {
4364         case IPSTATS_MIB_INNOROUTES:
4365                 type = ipv6_addr_type(&ipv6_hdr(skb)->daddr);
4366                 if (type == IPV6_ADDR_ANY) {
4367                         IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
4368                         break;
4369                 }
4370                 fallthrough;
4371         case IPSTATS_MIB_OUTNOROUTES:
4372                 IP6_INC_STATS(net, idev, ipstats_mib_noroutes);
4373                 break;
4374         }
4375
4376         /* Start over by dropping the dst for l3mdev case */
4377         if (netif_is_l3_master(skb->dev))
4378                 skb_dst_drop(skb);
4379
4380         icmpv6_send(skb, ICMPV6_DEST_UNREACH, code, 0);
4381         kfree_skb(skb);
4382         return 0;
4383 }
4384
4385 static int ip6_pkt_discard(struct sk_buff *skb)
4386 {
4387         return ip6_pkt_drop(skb, ICMPV6_NOROUTE, IPSTATS_MIB_INNOROUTES);
4388 }
4389
4390 static int ip6_pkt_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
4391 {
4392         skb->dev = skb_dst(skb)->dev;
4393         return ip6_pkt_drop(skb, ICMPV6_NOROUTE, IPSTATS_MIB_OUTNOROUTES);
4394 }
4395
4396 static int ip6_pkt_prohibit(struct sk_buff *skb)
4397 {
4398         return ip6_pkt_drop(skb, ICMPV6_ADM_PROHIBITED, IPSTATS_MIB_INNOROUTES);
4399 }
4400
4401 static int ip6_pkt_prohibit_out(struct net *net, struct sock *sk, struct sk_buff *skb)
4402 {
4403         skb->dev = skb_dst(skb)->dev;
4404         return ip6_pkt_drop(skb, ICMPV6_ADM_PROHIBITED, IPSTATS_MIB_OUTNOROUTES);
4405 }
4406
4407 /*
4408  *      Allocate a dst for local (unicast / anycast) address.
4409  */
4410
4411 struct fib6_info *addrconf_f6i_alloc(struct net *net,
4412                                      struct inet6_dev *idev,
4413                                      const struct in6_addr *addr,
4414                                      bool anycast, gfp_t gfp_flags)
4415 {
4416         struct fib6_config cfg = {
4417                 .fc_table = l3mdev_fib_table(idev->dev) ? : RT6_TABLE_LOCAL,
4418                 .fc_ifindex = idev->dev->ifindex,
4419                 .fc_flags = RTF_UP | RTF_NONEXTHOP,
4420                 .fc_dst = *addr,
4421                 .fc_dst_len = 128,
4422                 .fc_protocol = RTPROT_KERNEL,
4423                 .fc_nlinfo.nl_net = net,
4424                 .fc_ignore_dev_down = true,
4425         };
4426         struct fib6_info *f6i;
4427
4428         if (anycast) {
4429                 cfg.fc_type = RTN_ANYCAST;
4430                 cfg.fc_flags |= RTF_ANYCAST;
4431         } else {
4432                 cfg.fc_type = RTN_LOCAL;
4433                 cfg.fc_flags |= RTF_LOCAL;
4434         }
4435
4436         f6i = ip6_route_info_create(&cfg, gfp_flags, NULL);
4437         if (!IS_ERR(f6i))
4438                 f6i->dst_nocount = true;
4439         return f6i;
4440 }
4441
4442 /* remove deleted ip from prefsrc entries */
4443 struct arg_dev_net_ip {
4444         struct net_device *dev;
4445         struct net *net;
4446         struct in6_addr *addr;
4447 };
4448
4449 static int fib6_remove_prefsrc(struct fib6_info *rt, void *arg)
4450 {
4451         struct net_device *dev = ((struct arg_dev_net_ip *)arg)->dev;
4452         struct net *net = ((struct arg_dev_net_ip *)arg)->net;
4453         struct in6_addr *addr = ((struct arg_dev_net_ip *)arg)->addr;
4454
4455         if (!rt->nh &&
4456             ((void *)rt->fib6_nh->fib_nh_dev == dev || !dev) &&
4457             rt != net->ipv6.fib6_null_entry &&
4458             ipv6_addr_equal(addr, &rt->fib6_prefsrc.addr)) {
4459                 spin_lock_bh(&rt6_exception_lock);
4460                 /* remove prefsrc entry */
4461                 rt->fib6_prefsrc.plen = 0;
4462                 spin_unlock_bh(&rt6_exception_lock);
4463         }
4464         return 0;
4465 }
4466
4467 void rt6_remove_prefsrc(struct inet6_ifaddr *ifp)
4468 {
4469         struct net *net = dev_net(ifp->idev->dev);
4470         struct arg_dev_net_ip adni = {
4471                 .dev = ifp->idev->dev,
4472                 .net = net,
4473                 .addr = &ifp->addr,
4474         };
4475         fib6_clean_all(net, fib6_remove_prefsrc, &adni);
4476 }
4477
4478 #define RTF_RA_ROUTER           (RTF_ADDRCONF | RTF_DEFAULT)
4479
4480 /* Remove routers and update dst entries when gateway turn into host. */
4481 static int fib6_clean_tohost(struct fib6_info *rt, void *arg)
4482 {
4483         struct in6_addr *gateway = (struct in6_addr *)arg;
4484         struct fib6_nh *nh;
4485
4486         /* RA routes do not use nexthops */
4487         if (rt->nh)
4488                 return 0;
4489
4490         nh = rt->fib6_nh;
4491         if (((rt->fib6_flags & RTF_RA_ROUTER) == RTF_RA_ROUTER) &&
4492             nh->fib_nh_gw_family && ipv6_addr_equal(gateway, &nh->fib_nh_gw6))
4493                 return -1;
4494
4495         /* Further clean up cached routes in exception table.
4496          * This is needed because cached route may have a different
4497          * gateway than its 'parent' in the case of an ip redirect.
4498          */
4499         fib6_nh_exceptions_clean_tohost(nh, gateway);
4500
4501         return 0;
4502 }
4503
4504 void rt6_clean_tohost(struct net *net, struct in6_addr *gateway)
4505 {
4506         fib6_clean_all(net, fib6_clean_tohost, gateway);
4507 }
4508
4509 struct arg_netdev_event {
4510         const struct net_device *dev;
4511         union {
4512                 unsigned char nh_flags;
4513                 unsigned long event;
4514         };
4515 };
4516
4517 static struct fib6_info *rt6_multipath_first_sibling(const struct fib6_info *rt)
4518 {
4519         struct fib6_info *iter;
4520         struct fib6_node *fn;
4521
4522         fn = rcu_dereference_protected(rt->fib6_node,
4523                         lockdep_is_held(&rt->fib6_table->tb6_lock));
4524         iter = rcu_dereference_protected(fn->leaf,
4525                         lockdep_is_held(&rt->fib6_table->tb6_lock));
4526         while (iter) {
4527                 if (iter->fib6_metric == rt->fib6_metric &&
4528                     rt6_qualify_for_ecmp(iter))
4529                         return iter;
4530                 iter = rcu_dereference_protected(iter->fib6_next,
4531                                 lockdep_is_held(&rt->fib6_table->tb6_lock));
4532         }
4533
4534         return NULL;
4535 }
4536
4537 /* only called for fib entries with builtin fib6_nh */
4538 static bool rt6_is_dead(const struct fib6_info *rt)
4539 {
4540         if (rt->fib6_nh->fib_nh_flags & RTNH_F_DEAD ||
4541             (rt->fib6_nh->fib_nh_flags & RTNH_F_LINKDOWN &&
4542              ip6_ignore_linkdown(rt->fib6_nh->fib_nh_dev)))
4543                 return true;
4544
4545         return false;
4546 }
4547
4548 static int rt6_multipath_total_weight(const struct fib6_info *rt)
4549 {
4550         struct fib6_info *iter;
4551         int total = 0;
4552
4553         if (!rt6_is_dead(rt))
4554                 total += rt->fib6_nh->fib_nh_weight;
4555
4556         list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings) {
4557                 if (!rt6_is_dead(iter))
4558                         total += iter->fib6_nh->fib_nh_weight;
4559         }
4560
4561         return total;
4562 }
4563
4564 static void rt6_upper_bound_set(struct fib6_info *rt, int *weight, int total)
4565 {
4566         int upper_bound = -1;
4567
4568         if (!rt6_is_dead(rt)) {
4569                 *weight += rt->fib6_nh->fib_nh_weight;
4570                 upper_bound = DIV_ROUND_CLOSEST_ULL((u64) (*weight) << 31,
4571                                                     total) - 1;
4572         }
4573         atomic_set(&rt->fib6_nh->fib_nh_upper_bound, upper_bound);
4574 }
4575
4576 static void rt6_multipath_upper_bound_set(struct fib6_info *rt, int total)
4577 {
4578         struct fib6_info *iter;
4579         int weight = 0;
4580
4581         rt6_upper_bound_set(rt, &weight, total);
4582
4583         list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings)
4584                 rt6_upper_bound_set(iter, &weight, total);
4585 }
4586
4587 void rt6_multipath_rebalance(struct fib6_info *rt)
4588 {
4589         struct fib6_info *first;
4590         int total;
4591
4592         /* In case the entire multipath route was marked for flushing,
4593          * then there is no need to rebalance upon the removal of every
4594          * sibling route.
4595          */
4596         if (!rt->fib6_nsiblings || rt->should_flush)
4597                 return;
4598
4599         /* During lookup routes are evaluated in order, so we need to
4600          * make sure upper bounds are assigned from the first sibling
4601          * onwards.
4602          */
4603         first = rt6_multipath_first_sibling(rt);
4604         if (WARN_ON_ONCE(!first))
4605                 return;
4606
4607         total = rt6_multipath_total_weight(first);
4608         rt6_multipath_upper_bound_set(first, total);
4609 }
4610
4611 static int fib6_ifup(struct fib6_info *rt, void *p_arg)
4612 {
4613         const struct arg_netdev_event *arg = p_arg;
4614         struct net *net = dev_net(arg->dev);
4615
4616         if (rt != net->ipv6.fib6_null_entry && !rt->nh &&
4617             rt->fib6_nh->fib_nh_dev == arg->dev) {
4618                 rt->fib6_nh->fib_nh_flags &= ~arg->nh_flags;
4619                 fib6_update_sernum_upto_root(net, rt);
4620                 rt6_multipath_rebalance(rt);
4621         }
4622
4623         return 0;
4624 }
4625
4626 void rt6_sync_up(struct net_device *dev, unsigned char nh_flags)
4627 {
4628         struct arg_netdev_event arg = {
4629                 .dev = dev,
4630                 {
4631                         .nh_flags = nh_flags,
4632                 },
4633         };
4634
4635         if (nh_flags & RTNH_F_DEAD && netif_carrier_ok(dev))
4636                 arg.nh_flags |= RTNH_F_LINKDOWN;
4637
4638         fib6_clean_all(dev_net(dev), fib6_ifup, &arg);
4639 }
4640
4641 /* only called for fib entries with inline fib6_nh */
4642 static bool rt6_multipath_uses_dev(const struct fib6_info *rt,
4643                                    const struct net_device *dev)
4644 {
4645         struct fib6_info *iter;
4646
4647         if (rt->fib6_nh->fib_nh_dev == dev)
4648                 return true;
4649         list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings)
4650                 if (iter->fib6_nh->fib_nh_dev == dev)
4651                         return true;
4652
4653         return false;
4654 }
4655
4656 static void rt6_multipath_flush(struct fib6_info *rt)
4657 {
4658         struct fib6_info *iter;
4659
4660         rt->should_flush = 1;
4661         list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings)
4662                 iter->should_flush = 1;
4663 }
4664
4665 static unsigned int rt6_multipath_dead_count(const struct fib6_info *rt,
4666                                              const struct net_device *down_dev)
4667 {
4668         struct fib6_info *iter;
4669         unsigned int dead = 0;
4670
4671         if (rt->fib6_nh->fib_nh_dev == down_dev ||
4672             rt->fib6_nh->fib_nh_flags & RTNH_F_DEAD)
4673                 dead++;
4674         list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings)
4675                 if (iter->fib6_nh->fib_nh_dev == down_dev ||
4676                     iter->fib6_nh->fib_nh_flags & RTNH_F_DEAD)
4677                         dead++;
4678
4679         return dead;
4680 }
4681
4682 static void rt6_multipath_nh_flags_set(struct fib6_info *rt,
4683                                        const struct net_device *dev,
4684                                        unsigned char nh_flags)
4685 {
4686         struct fib6_info *iter;
4687
4688         if (rt->fib6_nh->fib_nh_dev == dev)
4689                 rt->fib6_nh->fib_nh_flags |= nh_flags;
4690         list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings)
4691                 if (iter->fib6_nh->fib_nh_dev == dev)
4692                         iter->fib6_nh->fib_nh_flags |= nh_flags;
4693 }
4694
4695 /* called with write lock held for table with rt */
4696 static int fib6_ifdown(struct fib6_info *rt, void *p_arg)
4697 {
4698         const struct arg_netdev_event *arg = p_arg;
4699         const struct net_device *dev = arg->dev;
4700         struct net *net = dev_net(dev);
4701
4702         if (rt == net->ipv6.fib6_null_entry || rt->nh)
4703                 return 0;
4704
4705         switch (arg->event) {
4706         case NETDEV_UNREGISTER:
4707                 return rt->fib6_nh->fib_nh_dev == dev ? -1 : 0;
4708         case NETDEV_DOWN:
4709                 if (rt->should_flush)
4710                         return -1;
4711                 if (!rt->fib6_nsiblings)
4712                         return rt->fib6_nh->fib_nh_dev == dev ? -1 : 0;
4713                 if (rt6_multipath_uses_dev(rt, dev)) {
4714                         unsigned int count;
4715
4716                         count = rt6_multipath_dead_count(rt, dev);
4717                         if (rt->fib6_nsiblings + 1 == count) {
4718                                 rt6_multipath_flush(rt);
4719                                 return -1;
4720                         }
4721                         rt6_multipath_nh_flags_set(rt, dev, RTNH_F_DEAD |
4722                                                    RTNH_F_LINKDOWN);
4723                         fib6_update_sernum(net, rt);
4724                         rt6_multipath_rebalance(rt);
4725                 }
4726                 return -2;
4727         case NETDEV_CHANGE:
4728                 if (rt->fib6_nh->fib_nh_dev != dev ||
4729                     rt->fib6_flags & (RTF_LOCAL | RTF_ANYCAST))
4730                         break;
4731                 rt->fib6_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
4732                 rt6_multipath_rebalance(rt);
4733                 break;
4734         }
4735
4736         return 0;
4737 }
4738
4739 void rt6_sync_down_dev(struct net_device *dev, unsigned long event)
4740 {
4741         struct arg_netdev_event arg = {
4742                 .dev = dev,
4743                 {
4744                         .event = event,
4745                 },
4746         };
4747         struct net *net = dev_net(dev);
4748
4749         if (net->ipv6.sysctl.skip_notify_on_dev_down)
4750                 fib6_clean_all_skip_notify(net, fib6_ifdown, &arg);
4751         else
4752                 fib6_clean_all(net, fib6_ifdown, &arg);
4753 }
4754
4755 void rt6_disable_ip(struct net_device *dev, unsigned long event)
4756 {
4757         rt6_sync_down_dev(dev, event);
4758         rt6_uncached_list_flush_dev(dev_net(dev), dev);
4759         neigh_ifdown(&nd_tbl, dev);
4760 }
4761
4762 struct rt6_mtu_change_arg {
4763         struct net_device *dev;
4764         unsigned int mtu;
4765         struct fib6_info *f6i;
4766 };
4767
4768 static int fib6_nh_mtu_change(struct fib6_nh *nh, void *_arg)
4769 {
4770         struct rt6_mtu_change_arg *arg = (struct rt6_mtu_change_arg *)_arg;
4771         struct fib6_info *f6i = arg->f6i;
4772
4773         /* For administrative MTU increase, there is no way to discover
4774          * IPv6 PMTU increase, so PMTU increase should be updated here.
4775          * Since RFC 1981 doesn't include administrative MTU increase
4776          * update PMTU increase is a MUST. (i.e. jumbo frame)
4777          */
4778         if (nh->fib_nh_dev == arg->dev) {
4779                 struct inet6_dev *idev = __in6_dev_get(arg->dev);
4780                 u32 mtu = f6i->fib6_pmtu;
4781
4782                 if (mtu >= arg->mtu ||
4783                     (mtu < arg->mtu && mtu == idev->cnf.mtu6))
4784                         fib6_metric_set(f6i, RTAX_MTU, arg->mtu);
4785
4786                 spin_lock_bh(&rt6_exception_lock);
4787                 rt6_exceptions_update_pmtu(idev, nh, arg->mtu);
4788                 spin_unlock_bh(&rt6_exception_lock);
4789         }
4790
4791         return 0;
4792 }
4793
4794 static int rt6_mtu_change_route(struct fib6_info *f6i, void *p_arg)
4795 {
4796         struct rt6_mtu_change_arg *arg = (struct rt6_mtu_change_arg *) p_arg;
4797         struct inet6_dev *idev;
4798
4799         /* In IPv6 pmtu discovery is not optional,
4800            so that RTAX_MTU lock cannot disable it.
4801            We still use this lock to block changes
4802            caused by addrconf/ndisc.
4803         */
4804
4805         idev = __in6_dev_get(arg->dev);
4806         if (!idev)
4807                 return 0;
4808
4809         if (fib6_metric_locked(f6i, RTAX_MTU))
4810                 return 0;
4811
4812         arg->f6i = f6i;
4813         if (f6i->nh) {
4814                 /* fib6_nh_mtu_change only returns 0, so this is safe */
4815                 return nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_mtu_change,
4816                                                 arg);
4817         }
4818
4819         return fib6_nh_mtu_change(f6i->fib6_nh, arg);
4820 }
4821
4822 void rt6_mtu_change(struct net_device *dev, unsigned int mtu)
4823 {
4824         struct rt6_mtu_change_arg arg = {
4825                 .dev = dev,
4826                 .mtu = mtu,
4827         };
4828
4829         fib6_clean_all(dev_net(dev), rt6_mtu_change_route, &arg);
4830 }
4831
4832 static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
4833         [RTA_UNSPEC]            = { .strict_start_type = RTA_DPORT + 1 },
4834         [RTA_GATEWAY]           = { .len = sizeof(struct in6_addr) },
4835         [RTA_PREFSRC]           = { .len = sizeof(struct in6_addr) },
4836         [RTA_OIF]               = { .type = NLA_U32 },
4837         [RTA_IIF]               = { .type = NLA_U32 },
4838         [RTA_PRIORITY]          = { .type = NLA_U32 },
4839         [RTA_METRICS]           = { .type = NLA_NESTED },
4840         [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
4841         [RTA_PREF]              = { .type = NLA_U8 },
4842         [RTA_ENCAP_TYPE]        = { .type = NLA_U16 },
4843         [RTA_ENCAP]             = { .type = NLA_NESTED },
4844         [RTA_EXPIRES]           = { .type = NLA_U32 },
4845         [RTA_UID]               = { .type = NLA_U32 },
4846         [RTA_MARK]              = { .type = NLA_U32 },
4847         [RTA_TABLE]             = { .type = NLA_U32 },
4848         [RTA_IP_PROTO]          = { .type = NLA_U8 },
4849         [RTA_SPORT]             = { .type = NLA_U16 },
4850         [RTA_DPORT]             = { .type = NLA_U16 },
4851         [RTA_NH_ID]             = { .type = NLA_U32 },
4852 };
4853
4854 static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
4855                               struct fib6_config *cfg,
4856                               struct netlink_ext_ack *extack)
4857 {
4858         struct rtmsg *rtm;
4859         struct nlattr *tb[RTA_MAX+1];
4860         unsigned int pref;
4861         int err;
4862
4863         err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
4864                                      rtm_ipv6_policy, extack);
4865         if (err < 0)
4866                 goto errout;
4867
4868         err = -EINVAL;
4869         rtm = nlmsg_data(nlh);
4870
4871         *cfg = (struct fib6_config){
4872                 .fc_table = rtm->rtm_table,
4873                 .fc_dst_len = rtm->rtm_dst_len,
4874                 .fc_src_len = rtm->rtm_src_len,
4875                 .fc_flags = RTF_UP,
4876                 .fc_protocol = rtm->rtm_protocol,
4877                 .fc_type = rtm->rtm_type,
4878
4879                 .fc_nlinfo.portid = NETLINK_CB(skb).portid,
4880                 .fc_nlinfo.nlh = nlh,
4881                 .fc_nlinfo.nl_net = sock_net(skb->sk),
4882         };
4883
4884         if (rtm->rtm_type == RTN_UNREACHABLE ||
4885             rtm->rtm_type == RTN_BLACKHOLE ||
4886             rtm->rtm_type == RTN_PROHIBIT ||
4887             rtm->rtm_type == RTN_THROW)
4888                 cfg->fc_flags |= RTF_REJECT;
4889
4890         if (rtm->rtm_type == RTN_LOCAL)
4891                 cfg->fc_flags |= RTF_LOCAL;
4892
4893         if (rtm->rtm_flags & RTM_F_CLONED)
4894                 cfg->fc_flags |= RTF_CACHE;
4895
4896         cfg->fc_flags |= (rtm->rtm_flags & RTNH_F_ONLINK);
4897
4898         if (tb[RTA_NH_ID]) {
4899                 if (tb[RTA_GATEWAY]   || tb[RTA_OIF] ||
4900                     tb[RTA_MULTIPATH] || tb[RTA_ENCAP]) {
4901                         NL_SET_ERR_MSG(extack,
4902                                        "Nexthop specification and nexthop id are mutually exclusive");
4903                         goto errout;
4904                 }
4905                 cfg->fc_nh_id = nla_get_u32(tb[RTA_NH_ID]);
4906         }
4907
4908         if (tb[RTA_GATEWAY]) {
4909                 cfg->fc_gateway = nla_get_in6_addr(tb[RTA_GATEWAY]);
4910                 cfg->fc_flags |= RTF_GATEWAY;
4911         }
4912         if (tb[RTA_VIA]) {
4913                 NL_SET_ERR_MSG(extack, "IPv6 does not support RTA_VIA attribute");
4914                 goto errout;
4915         }
4916
4917         if (tb[RTA_DST]) {
4918                 int plen = (rtm->rtm_dst_len + 7) >> 3;
4919
4920                 if (nla_len(tb[RTA_DST]) < plen)
4921                         goto errout;
4922
4923                 nla_memcpy(&cfg->fc_dst, tb[RTA_DST], plen);
4924         }
4925
4926         if (tb[RTA_SRC]) {
4927                 int plen = (rtm->rtm_src_len + 7) >> 3;
4928
4929                 if (nla_len(tb[RTA_SRC]) < plen)
4930                         goto errout;
4931
4932                 nla_memcpy(&cfg->fc_src, tb[RTA_SRC], plen);
4933         }
4934
4935         if (tb[RTA_PREFSRC])
4936                 cfg->fc_prefsrc = nla_get_in6_addr(tb[RTA_PREFSRC]);
4937
4938         if (tb[RTA_OIF])
4939                 cfg->fc_ifindex = nla_get_u32(tb[RTA_OIF]);
4940
4941         if (tb[RTA_PRIORITY])
4942                 cfg->fc_metric = nla_get_u32(tb[RTA_PRIORITY]);
4943
4944         if (tb[RTA_METRICS]) {
4945                 cfg->fc_mx = nla_data(tb[RTA_METRICS]);
4946                 cfg->fc_mx_len = nla_len(tb[RTA_METRICS]);
4947         }
4948
4949         if (tb[RTA_TABLE])
4950                 cfg->fc_table = nla_get_u32(tb[RTA_TABLE]);
4951
4952         if (tb[RTA_MULTIPATH]) {
4953                 cfg->fc_mp = nla_data(tb[RTA_MULTIPATH]);
4954                 cfg->fc_mp_len = nla_len(tb[RTA_MULTIPATH]);
4955
4956                 err = lwtunnel_valid_encap_type_attr(cfg->fc_mp,
4957                                                      cfg->fc_mp_len, extack);
4958                 if (err < 0)
4959                         goto errout;
4960         }
4961
4962         if (tb[RTA_PREF]) {
4963                 pref = nla_get_u8(tb[RTA_PREF]);
4964                 if (pref != ICMPV6_ROUTER_PREF_LOW &&
4965                     pref != ICMPV6_ROUTER_PREF_HIGH)
4966                         pref = ICMPV6_ROUTER_PREF_MEDIUM;
4967                 cfg->fc_flags |= RTF_PREF(pref);
4968         }
4969
4970         if (tb[RTA_ENCAP])
4971                 cfg->fc_encap = tb[RTA_ENCAP];
4972
4973         if (tb[RTA_ENCAP_TYPE]) {
4974                 cfg->fc_encap_type = nla_get_u16(tb[RTA_ENCAP_TYPE]);
4975
4976                 err = lwtunnel_valid_encap_type(cfg->fc_encap_type, extack);
4977                 if (err < 0)
4978                         goto errout;
4979         }
4980
4981         if (tb[RTA_EXPIRES]) {
4982                 unsigned long timeout = addrconf_timeout_fixup(nla_get_u32(tb[RTA_EXPIRES]), HZ);
4983
4984                 if (addrconf_finite_timeout(timeout)) {
4985                         cfg->fc_expires = jiffies_to_clock_t(timeout * HZ);
4986                         cfg->fc_flags |= RTF_EXPIRES;
4987                 }
4988         }
4989
4990         err = 0;
4991 errout:
4992         return err;
4993 }
4994
4995 struct rt6_nh {
4996         struct fib6_info *fib6_info;
4997         struct fib6_config r_cfg;
4998         struct list_head next;
4999 };
5000
5001 static int ip6_route_info_append(struct net *net,
5002                                  struct list_head *rt6_nh_list,
5003                                  struct fib6_info *rt,
5004                                  struct fib6_config *r_cfg)
5005 {
5006         struct rt6_nh *nh;
5007         int err = -EEXIST;
5008
5009         list_for_each_entry(nh, rt6_nh_list, next) {
5010                 /* check if fib6_info already exists */
5011                 if (rt6_duplicate_nexthop(nh->fib6_info, rt))
5012                         return err;
5013         }
5014
5015         nh = kzalloc(sizeof(*nh), GFP_KERNEL);
5016         if (!nh)
5017                 return -ENOMEM;
5018         nh->fib6_info = rt;
5019         memcpy(&nh->r_cfg, r_cfg, sizeof(*r_cfg));
5020         list_add_tail(&nh->next, rt6_nh_list);
5021
5022         return 0;
5023 }
5024
5025 static void ip6_route_mpath_notify(struct fib6_info *rt,
5026                                    struct fib6_info *rt_last,
5027                                    struct nl_info *info,
5028                                    __u16 nlflags)
5029 {
5030         /* if this is an APPEND route, then rt points to the first route
5031          * inserted and rt_last points to last route inserted. Userspace
5032          * wants a consistent dump of the route which starts at the first
5033          * nexthop. Since sibling routes are always added at the end of
5034          * the list, find the first sibling of the last route appended
5035          */
5036         if ((nlflags & NLM_F_APPEND) && rt_last && rt_last->fib6_nsiblings) {
5037                 rt = list_first_entry(&rt_last->fib6_siblings,
5038                                       struct fib6_info,
5039                                       fib6_siblings);
5040         }
5041
5042         if (rt)
5043                 inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
5044 }
5045
5046 static bool ip6_route_mpath_should_notify(const struct fib6_info *rt)
5047 {
5048         bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
5049         bool should_notify = false;
5050         struct fib6_info *leaf;
5051         struct fib6_node *fn;
5052
5053         rcu_read_lock();
5054         fn = rcu_dereference(rt->fib6_node);
5055         if (!fn)
5056                 goto out;
5057
5058         leaf = rcu_dereference(fn->leaf);
5059         if (!leaf)
5060                 goto out;
5061
5062         if (rt == leaf ||
5063             (rt_can_ecmp && rt->fib6_metric == leaf->fib6_metric &&
5064              rt6_qualify_for_ecmp(leaf)))
5065                 should_notify = true;
5066 out:
5067         rcu_read_unlock();
5068
5069         return should_notify;
5070 }
5071
5072 static int ip6_route_multipath_add(struct fib6_config *cfg,
5073                                    struct netlink_ext_ack *extack)
5074 {
5075         struct fib6_info *rt_notif = NULL, *rt_last = NULL;
5076         struct nl_info *info = &cfg->fc_nlinfo;
5077         struct fib6_config r_cfg;
5078         struct rtnexthop *rtnh;
5079         struct fib6_info *rt;
5080         struct rt6_nh *err_nh;
5081         struct rt6_nh *nh, *nh_safe;
5082         __u16 nlflags;
5083         int remaining;
5084         int attrlen;
5085         int err = 1;
5086         int nhn = 0;
5087         int replace = (cfg->fc_nlinfo.nlh &&
5088                        (cfg->fc_nlinfo.nlh->nlmsg_flags & NLM_F_REPLACE));
5089         LIST_HEAD(rt6_nh_list);
5090
5091         nlflags = replace ? NLM_F_REPLACE : NLM_F_CREATE;
5092         if (info->nlh && info->nlh->nlmsg_flags & NLM_F_APPEND)
5093                 nlflags |= NLM_F_APPEND;
5094
5095         remaining = cfg->fc_mp_len;
5096         rtnh = (struct rtnexthop *)cfg->fc_mp;
5097
5098         /* Parse a Multipath Entry and build a list (rt6_nh_list) of
5099          * fib6_info structs per nexthop
5100          */
5101         while (rtnh_ok(rtnh, remaining)) {
5102                 memcpy(&r_cfg, cfg, sizeof(*cfg));
5103                 if (rtnh->rtnh_ifindex)
5104                         r_cfg.fc_ifindex = rtnh->rtnh_ifindex;
5105
5106                 attrlen = rtnh_attrlen(rtnh);
5107                 if (attrlen > 0) {
5108                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
5109
5110                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
5111                         if (nla) {
5112                                 r_cfg.fc_gateway = nla_get_in6_addr(nla);
5113                                 r_cfg.fc_flags |= RTF_GATEWAY;
5114                         }
5115                         r_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
5116                         nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
5117                         if (nla)
5118                                 r_cfg.fc_encap_type = nla_get_u16(nla);
5119                 }
5120
5121                 r_cfg.fc_flags |= (rtnh->rtnh_flags & RTNH_F_ONLINK);
5122                 rt = ip6_route_info_create(&r_cfg, GFP_KERNEL, extack);
5123                 if (IS_ERR(rt)) {
5124                         err = PTR_ERR(rt);
5125                         rt = NULL;
5126                         goto cleanup;
5127                 }
5128                 if (!rt6_qualify_for_ecmp(rt)) {
5129                         err = -EINVAL;
5130                         NL_SET_ERR_MSG(extack,
5131                                        "Device only routes can not be added for IPv6 using the multipath API.");
5132                         fib6_info_release(rt);
5133                         goto cleanup;
5134                 }
5135
5136                 rt->fib6_nh->fib_nh_weight = rtnh->rtnh_hops + 1;
5137
5138                 err = ip6_route_info_append(info->nl_net, &rt6_nh_list,
5139                                             rt, &r_cfg);
5140                 if (err) {
5141                         fib6_info_release(rt);
5142                         goto cleanup;
5143                 }
5144
5145                 rtnh = rtnh_next(rtnh, &remaining);
5146         }
5147
5148         if (list_empty(&rt6_nh_list)) {
5149                 NL_SET_ERR_MSG(extack,
5150                                "Invalid nexthop configuration - no valid nexthops");
5151                 return -EINVAL;
5152         }
5153
5154         /* for add and replace send one notification with all nexthops.
5155          * Skip the notification in fib6_add_rt2node and send one with
5156          * the full route when done
5157          */
5158         info->skip_notify = 1;
5159
5160         /* For add and replace, send one notification with all nexthops. For
5161          * append, send one notification with all appended nexthops.
5162          */
5163         info->skip_notify_kernel = 1;
5164
5165         err_nh = NULL;
5166         list_for_each_entry(nh, &rt6_nh_list, next) {
5167                 err = __ip6_ins_rt(nh->fib6_info, info, extack);
5168                 fib6_info_release(nh->fib6_info);
5169
5170                 if (!err) {
5171                         /* save reference to last route successfully inserted */
5172                         rt_last = nh->fib6_info;
5173
5174                         /* save reference to first route for notification */
5175                         if (!rt_notif)
5176                                 rt_notif = nh->fib6_info;
5177                 }
5178
5179                 /* nh->fib6_info is used or freed at this point, reset to NULL*/
5180                 nh->fib6_info = NULL;
5181                 if (err) {
5182                         if (replace && nhn)
5183                                 NL_SET_ERR_MSG_MOD(extack,
5184                                                    "multipath route replace failed (check consistency of installed routes)");
5185                         err_nh = nh;
5186                         goto add_errout;
5187                 }
5188
5189                 /* Because each route is added like a single route we remove
5190                  * these flags after the first nexthop: if there is a collision,
5191                  * we have already failed to add the first nexthop:
5192                  * fib6_add_rt2node() has rejected it; when replacing, old
5193                  * nexthops have been replaced by first new, the rest should
5194                  * be added to it.
5195                  */
5196                 cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL |
5197                                                      NLM_F_REPLACE);
5198                 cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_CREATE;
5199                 nhn++;
5200         }
5201
5202         /* An in-kernel notification should only be sent in case the new
5203          * multipath route is added as the first route in the node, or if
5204          * it was appended to it. We pass 'rt_notif' since it is the first
5205          * sibling and might allow us to skip some checks in the replace case.
5206          */
5207         if (ip6_route_mpath_should_notify(rt_notif)) {
5208                 enum fib_event_type fib_event;
5209
5210                 if (rt_notif->fib6_nsiblings != nhn - 1)
5211                         fib_event = FIB_EVENT_ENTRY_APPEND;
5212                 else
5213                         fib_event = FIB_EVENT_ENTRY_REPLACE;
5214
5215                 err = call_fib6_multipath_entry_notifiers(info->nl_net,
5216                                                           fib_event, rt_notif,
5217                                                           nhn - 1, extack);
5218                 if (err) {
5219                         /* Delete all the siblings that were just added */
5220                         err_nh = NULL;
5221                         goto add_errout;
5222                 }
5223         }
5224
5225         /* success ... tell user about new route */
5226         ip6_route_mpath_notify(rt_notif, rt_last, info, nlflags);
5227         goto cleanup;
5228
5229 add_errout:
5230         /* send notification for routes that were added so that
5231          * the delete notifications sent by ip6_route_del are
5232          * coherent
5233          */
5234         if (rt_notif)
5235                 ip6_route_mpath_notify(rt_notif, rt_last, info, nlflags);
5236
5237         /* Delete routes that were already added */
5238         list_for_each_entry(nh, &rt6_nh_list, next) {
5239                 if (err_nh == nh)
5240                         break;
5241                 ip6_route_del(&nh->r_cfg, extack);
5242         }
5243
5244 cleanup:
5245         list_for_each_entry_safe(nh, nh_safe, &rt6_nh_list, next) {
5246                 if (nh->fib6_info)
5247                         fib6_info_release(nh->fib6_info);
5248                 list_del(&nh->next);
5249                 kfree(nh);
5250         }
5251
5252         return err;
5253 }
5254
5255 static int ip6_route_multipath_del(struct fib6_config *cfg,
5256                                    struct netlink_ext_ack *extack)
5257 {
5258         struct fib6_config r_cfg;
5259         struct rtnexthop *rtnh;
5260         int remaining;
5261         int attrlen;
5262         int err = 1, last_err = 0;
5263
5264         remaining = cfg->fc_mp_len;
5265         rtnh = (struct rtnexthop *)cfg->fc_mp;
5266
5267         /* Parse a Multipath Entry */
5268         while (rtnh_ok(rtnh, remaining)) {
5269                 memcpy(&r_cfg, cfg, sizeof(*cfg));
5270                 if (rtnh->rtnh_ifindex)
5271                         r_cfg.fc_ifindex = rtnh->rtnh_ifindex;
5272
5273                 attrlen = rtnh_attrlen(rtnh);
5274                 if (attrlen > 0) {
5275                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
5276
5277                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
5278                         if (nla) {
5279                                 nla_memcpy(&r_cfg.fc_gateway, nla, 16);
5280                                 r_cfg.fc_flags |= RTF_GATEWAY;
5281                         }
5282                 }
5283                 err = ip6_route_del(&r_cfg, extack);
5284                 if (err)
5285                         last_err = err;
5286
5287                 rtnh = rtnh_next(rtnh, &remaining);
5288         }
5289
5290         return last_err;
5291 }
5292
5293 static int inet6_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
5294                               struct netlink_ext_ack *extack)
5295 {
5296         struct fib6_config cfg;
5297         int err;
5298
5299         err = rtm_to_fib6_config(skb, nlh, &cfg, extack);
5300         if (err < 0)
5301                 return err;
5302
5303         if (cfg.fc_nh_id &&
5304             !nexthop_find_by_id(sock_net(skb->sk), cfg.fc_nh_id)) {
5305                 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
5306                 return -EINVAL;
5307         }
5308
5309         if (cfg.fc_mp)
5310                 return ip6_route_multipath_del(&cfg, extack);
5311         else {
5312                 cfg.fc_delete_all_nh = 1;
5313                 return ip6_route_del(&cfg, extack);
5314         }
5315 }
5316
5317 static int inet6_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
5318                               struct netlink_ext_ack *extack)
5319 {
5320         struct fib6_config cfg;
5321         int err;
5322
5323         err = rtm_to_fib6_config(skb, nlh, &cfg, extack);
5324         if (err < 0)
5325                 return err;
5326
5327         if (cfg.fc_metric == 0)
5328                 cfg.fc_metric = IP6_RT_PRIO_USER;
5329
5330         if (cfg.fc_mp)
5331                 return ip6_route_multipath_add(&cfg, extack);
5332         else
5333                 return ip6_route_add(&cfg, GFP_KERNEL, extack);
5334 }
5335
5336 /* add the overhead of this fib6_nh to nexthop_len */
5337 static int rt6_nh_nlmsg_size(struct fib6_nh *nh, void *arg)
5338 {
5339         int *nexthop_len = arg;
5340
5341         *nexthop_len += nla_total_size(0)        /* RTA_MULTIPATH */
5342                      + NLA_ALIGN(sizeof(struct rtnexthop))
5343                      + nla_total_size(16); /* RTA_GATEWAY */
5344
5345         if (nh->fib_nh_lws) {
5346                 /* RTA_ENCAP_TYPE */
5347                 *nexthop_len += lwtunnel_get_encap_size(nh->fib_nh_lws);
5348                 /* RTA_ENCAP */
5349                 *nexthop_len += nla_total_size(2);
5350         }
5351
5352         return 0;
5353 }
5354
5355 static size_t rt6_nlmsg_size(struct fib6_info *f6i)
5356 {
5357         int nexthop_len;
5358
5359         if (f6i->nh) {
5360                 nexthop_len = nla_total_size(4); /* RTA_NH_ID */
5361                 nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_nlmsg_size,
5362                                          &nexthop_len);
5363         } else {
5364                 struct fib6_nh *nh = f6i->fib6_nh;
5365
5366                 nexthop_len = 0;
5367                 if (f6i->fib6_nsiblings) {
5368                         nexthop_len = nla_total_size(0)  /* RTA_MULTIPATH */
5369                                     + NLA_ALIGN(sizeof(struct rtnexthop))
5370                                     + nla_total_size(16) /* RTA_GATEWAY */
5371                                     + lwtunnel_get_encap_size(nh->fib_nh_lws);
5372
5373                         nexthop_len *= f6i->fib6_nsiblings;
5374                 }
5375                 nexthop_len += lwtunnel_get_encap_size(nh->fib_nh_lws);
5376         }
5377
5378         return NLMSG_ALIGN(sizeof(struct rtmsg))
5379                + nla_total_size(16) /* RTA_SRC */
5380                + nla_total_size(16) /* RTA_DST */
5381                + nla_total_size(16) /* RTA_GATEWAY */
5382                + nla_total_size(16) /* RTA_PREFSRC */
5383                + nla_total_size(4) /* RTA_TABLE */
5384                + nla_total_size(4) /* RTA_IIF */
5385                + nla_total_size(4) /* RTA_OIF */
5386                + nla_total_size(4) /* RTA_PRIORITY */
5387                + RTAX_MAX * nla_total_size(4) /* RTA_METRICS */
5388                + nla_total_size(sizeof(struct rta_cacheinfo))
5389                + nla_total_size(TCP_CA_NAME_MAX) /* RTAX_CC_ALGO */
5390                + nla_total_size(1) /* RTA_PREF */
5391                + nexthop_len;
5392 }
5393
5394 static int rt6_fill_node_nexthop(struct sk_buff *skb, struct nexthop *nh,
5395                                  unsigned char *flags)
5396 {
5397         if (nexthop_is_multipath(nh)) {
5398                 struct nlattr *mp;
5399
5400                 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
5401                 if (!mp)
5402                         goto nla_put_failure;
5403
5404                 if (nexthop_mpath_fill_node(skb, nh, AF_INET6))
5405                         goto nla_put_failure;
5406
5407                 nla_nest_end(skb, mp);
5408         } else {
5409                 struct fib6_nh *fib6_nh;
5410
5411                 fib6_nh = nexthop_fib6_nh(nh);
5412                 if (fib_nexthop_info(skb, &fib6_nh->nh_common, AF_INET6,
5413                                      flags, false) < 0)
5414                         goto nla_put_failure;
5415         }
5416
5417         return 0;
5418
5419 nla_put_failure:
5420         return -EMSGSIZE;
5421 }
5422
5423 static int rt6_fill_node(struct net *net, struct sk_buff *skb,
5424                          struct fib6_info *rt, struct dst_entry *dst,
5425                          struct in6_addr *dest, struct in6_addr *src,
5426                          int iif, int type, u32 portid, u32 seq,
5427                          unsigned int flags)
5428 {
5429         struct rt6_info *rt6 = (struct rt6_info *)dst;
5430         struct rt6key *rt6_dst, *rt6_src;
5431         u32 *pmetrics, table, rt6_flags;
5432         unsigned char nh_flags = 0;
5433         struct nlmsghdr *nlh;
5434         struct rtmsg *rtm;
5435         long expires = 0;
5436
5437         nlh = nlmsg_put(skb, portid, seq, type, sizeof(*rtm), flags);
5438         if (!nlh)
5439                 return -EMSGSIZE;
5440
5441         if (rt6) {
5442                 rt6_dst = &rt6->rt6i_dst;
5443                 rt6_src = &rt6->rt6i_src;
5444                 rt6_flags = rt6->rt6i_flags;
5445         } else {
5446                 rt6_dst = &rt->fib6_dst;
5447                 rt6_src = &rt->fib6_src;
5448                 rt6_flags = rt->fib6_flags;
5449         }
5450
5451         rtm = nlmsg_data(nlh);
5452         rtm->rtm_family = AF_INET6;
5453         rtm->rtm_dst_len = rt6_dst->plen;
5454         rtm->rtm_src_len = rt6_src->plen;
5455         rtm->rtm_tos = 0;
5456         if (rt->fib6_table)
5457                 table = rt->fib6_table->tb6_id;
5458         else
5459                 table = RT6_TABLE_UNSPEC;
5460         rtm->rtm_table = table < 256 ? table : RT_TABLE_COMPAT;
5461         if (nla_put_u32(skb, RTA_TABLE, table))
5462                 goto nla_put_failure;
5463
5464         rtm->rtm_type = rt->fib6_type;
5465         rtm->rtm_flags = 0;
5466         rtm->rtm_scope = RT_SCOPE_UNIVERSE;
5467         rtm->rtm_protocol = rt->fib6_protocol;
5468
5469         if (rt6_flags & RTF_CACHE)
5470                 rtm->rtm_flags |= RTM_F_CLONED;
5471
5472         if (dest) {
5473                 if (nla_put_in6_addr(skb, RTA_DST, dest))
5474                         goto nla_put_failure;
5475                 rtm->rtm_dst_len = 128;
5476         } else if (rtm->rtm_dst_len)
5477                 if (nla_put_in6_addr(skb, RTA_DST, &rt6_dst->addr))
5478                         goto nla_put_failure;
5479 #ifdef CONFIG_IPV6_SUBTREES
5480         if (src) {
5481                 if (nla_put_in6_addr(skb, RTA_SRC, src))
5482                         goto nla_put_failure;
5483                 rtm->rtm_src_len = 128;
5484         } else if (rtm->rtm_src_len &&
5485                    nla_put_in6_addr(skb, RTA_SRC, &rt6_src->addr))
5486                 goto nla_put_failure;
5487 #endif
5488         if (iif) {
5489 #ifdef CONFIG_IPV6_MROUTE
5490                 if (ipv6_addr_is_multicast(&rt6_dst->addr)) {
5491                         int err = ip6mr_get_route(net, skb, rtm, portid);
5492
5493                         if (err == 0)
5494                                 return 0;
5495                         if (err < 0)
5496                                 goto nla_put_failure;
5497                 } else
5498 #endif
5499                         if (nla_put_u32(skb, RTA_IIF, iif))
5500                                 goto nla_put_failure;
5501         } else if (dest) {
5502                 struct in6_addr saddr_buf;
5503                 if (ip6_route_get_saddr(net, rt, dest, 0, &saddr_buf) == 0 &&
5504                     nla_put_in6_addr(skb, RTA_PREFSRC, &saddr_buf))
5505                         goto nla_put_failure;
5506         }
5507
5508         if (rt->fib6_prefsrc.plen) {
5509                 struct in6_addr saddr_buf;
5510                 saddr_buf = rt->fib6_prefsrc.addr;
5511                 if (nla_put_in6_addr(skb, RTA_PREFSRC, &saddr_buf))
5512                         goto nla_put_failure;
5513         }
5514
5515         pmetrics = dst ? dst_metrics_ptr(dst) : rt->fib6_metrics->metrics;
5516         if (rtnetlink_put_metrics(skb, pmetrics) < 0)
5517                 goto nla_put_failure;
5518
5519         if (nla_put_u32(skb, RTA_PRIORITY, rt->fib6_metric))
5520                 goto nla_put_failure;
5521
5522         /* For multipath routes, walk the siblings list and add
5523          * each as a nexthop within RTA_MULTIPATH.
5524          */
5525         if (rt6) {
5526                 if (rt6_flags & RTF_GATEWAY &&
5527                     nla_put_in6_addr(skb, RTA_GATEWAY, &rt6->rt6i_gateway))
5528                         goto nla_put_failure;
5529
5530                 if (dst->dev && nla_put_u32(skb, RTA_OIF, dst->dev->ifindex))
5531                         goto nla_put_failure;
5532         } else if (rt->fib6_nsiblings) {
5533                 struct fib6_info *sibling, *next_sibling;
5534                 struct nlattr *mp;
5535
5536                 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
5537                 if (!mp)
5538                         goto nla_put_failure;
5539
5540                 if (fib_add_nexthop(skb, &rt->fib6_nh->nh_common,
5541                                     rt->fib6_nh->fib_nh_weight, AF_INET6) < 0)
5542                         goto nla_put_failure;
5543
5544                 list_for_each_entry_safe(sibling, next_sibling,
5545                                          &rt->fib6_siblings, fib6_siblings) {
5546                         if (fib_add_nexthop(skb, &sibling->fib6_nh->nh_common,
5547                                             sibling->fib6_nh->fib_nh_weight,
5548                                             AF_INET6) < 0)
5549                                 goto nla_put_failure;
5550                 }
5551
5552                 nla_nest_end(skb, mp);
5553         } else if (rt->nh) {
5554                 if (nla_put_u32(skb, RTA_NH_ID, rt->nh->id))
5555                         goto nla_put_failure;
5556
5557                 if (nexthop_is_blackhole(rt->nh))
5558                         rtm->rtm_type = RTN_BLACKHOLE;
5559
5560                 if (net->ipv4.sysctl_nexthop_compat_mode &&
5561                     rt6_fill_node_nexthop(skb, rt->nh, &nh_flags) < 0)
5562                         goto nla_put_failure;
5563
5564                 rtm->rtm_flags |= nh_flags;
5565         } else {
5566                 if (fib_nexthop_info(skb, &rt->fib6_nh->nh_common, AF_INET6,
5567                                      &nh_flags, false) < 0)
5568                         goto nla_put_failure;
5569
5570                 rtm->rtm_flags |= nh_flags;
5571         }
5572
5573         if (rt6_flags & RTF_EXPIRES) {
5574                 expires = dst ? dst->expires : rt->expires;
5575                 expires -= jiffies;
5576         }
5577
5578         if (!dst) {
5579                 if (rt->offload)
5580                         rtm->rtm_flags |= RTM_F_OFFLOAD;
5581                 if (rt->trap)
5582                         rtm->rtm_flags |= RTM_F_TRAP;
5583         }
5584
5585         if (rtnl_put_cacheinfo(skb, dst, 0, expires, dst ? dst->error : 0) < 0)
5586                 goto nla_put_failure;
5587
5588         if (nla_put_u8(skb, RTA_PREF, IPV6_EXTRACT_PREF(rt6_flags)))
5589                 goto nla_put_failure;
5590
5591
5592         nlmsg_end(skb, nlh);
5593         return 0;
5594
5595 nla_put_failure:
5596         nlmsg_cancel(skb, nlh);
5597         return -EMSGSIZE;
5598 }
5599
5600 static int fib6_info_nh_uses_dev(struct fib6_nh *nh, void *arg)
5601 {
5602         const struct net_device *dev = arg;
5603
5604         if (nh->fib_nh_dev == dev)
5605                 return 1;
5606
5607         return 0;
5608 }
5609
5610 static bool fib6_info_uses_dev(const struct fib6_info *f6i,
5611                                const struct net_device *dev)
5612 {
5613         if (f6i->nh) {
5614                 struct net_device *_dev = (struct net_device *)dev;
5615
5616                 return !!nexthop_for_each_fib6_nh(f6i->nh,
5617                                                   fib6_info_nh_uses_dev,
5618                                                   _dev);
5619         }
5620
5621         if (f6i->fib6_nh->fib_nh_dev == dev)
5622                 return true;
5623
5624         if (f6i->fib6_nsiblings) {
5625                 struct fib6_info *sibling, *next_sibling;
5626
5627                 list_for_each_entry_safe(sibling, next_sibling,
5628                                          &f6i->fib6_siblings, fib6_siblings) {
5629                         if (sibling->fib6_nh->fib_nh_dev == dev)
5630                                 return true;
5631                 }
5632         }
5633
5634         return false;
5635 }
5636
5637 struct fib6_nh_exception_dump_walker {
5638         struct rt6_rtnl_dump_arg *dump;
5639         struct fib6_info *rt;
5640         unsigned int flags;
5641         unsigned int skip;
5642         unsigned int count;
5643 };
5644
5645 static int rt6_nh_dump_exceptions(struct fib6_nh *nh, void *arg)
5646 {
5647         struct fib6_nh_exception_dump_walker *w = arg;
5648         struct rt6_rtnl_dump_arg *dump = w->dump;
5649         struct rt6_exception_bucket *bucket;
5650         struct rt6_exception *rt6_ex;
5651         int i, err;
5652
5653         bucket = fib6_nh_get_excptn_bucket(nh, NULL);
5654         if (!bucket)
5655                 return 0;
5656
5657         for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
5658                 hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
5659                         if (w->skip) {
5660                                 w->skip--;
5661                                 continue;
5662                         }
5663
5664                         /* Expiration of entries doesn't bump sernum, insertion
5665                          * does. Removal is triggered by insertion, so we can
5666                          * rely on the fact that if entries change between two
5667                          * partial dumps, this node is scanned again completely,
5668                          * see rt6_insert_exception() and fib6_dump_table().
5669                          *
5670                          * Count expired entries we go through as handled
5671                          * entries that we'll skip next time, in case of partial
5672                          * node dump. Otherwise, if entries expire meanwhile,
5673                          * we'll skip the wrong amount.
5674                          */
5675                         if (rt6_check_expired(rt6_ex->rt6i)) {
5676                                 w->count++;
5677                                 continue;
5678                         }
5679
5680                         err = rt6_fill_node(dump->net, dump->skb, w->rt,
5681                                             &rt6_ex->rt6i->dst, NULL, NULL, 0,
5682                                             RTM_NEWROUTE,
5683                                             NETLINK_CB(dump->cb->skb).portid,
5684                                             dump->cb->nlh->nlmsg_seq, w->flags);
5685                         if (err)
5686                                 return err;
5687
5688                         w->count++;
5689                 }
5690                 bucket++;
5691         }
5692
5693         return 0;
5694 }
5695
5696 /* Return -1 if done with node, number of handled routes on partial dump */
5697 int rt6_dump_route(struct fib6_info *rt, void *p_arg, unsigned int skip)
5698 {
5699         struct rt6_rtnl_dump_arg *arg = (struct rt6_rtnl_dump_arg *) p_arg;
5700         struct fib_dump_filter *filter = &arg->filter;
5701         unsigned int flags = NLM_F_MULTI;
5702         struct net *net = arg->net;
5703         int count = 0;
5704
5705         if (rt == net->ipv6.fib6_null_entry)
5706                 return -1;
5707
5708         if ((filter->flags & RTM_F_PREFIX) &&
5709             !(rt->fib6_flags & RTF_PREFIX_RT)) {
5710                 /* success since this is not a prefix route */
5711                 return -1;
5712         }
5713         if (filter->filter_set &&
5714             ((filter->rt_type  && rt->fib6_type != filter->rt_type) ||
5715              (filter->dev      && !fib6_info_uses_dev(rt, filter->dev)) ||
5716              (filter->protocol && rt->fib6_protocol != filter->protocol))) {
5717                 return -1;
5718         }
5719
5720         if (filter->filter_set ||
5721             !filter->dump_routes || !filter->dump_exceptions) {
5722                 flags |= NLM_F_DUMP_FILTERED;
5723         }
5724
5725         if (filter->dump_routes) {
5726                 if (skip) {
5727                         skip--;
5728                 } else {
5729                         if (rt6_fill_node(net, arg->skb, rt, NULL, NULL, NULL,
5730                                           0, RTM_NEWROUTE,
5731                                           NETLINK_CB(arg->cb->skb).portid,
5732                                           arg->cb->nlh->nlmsg_seq, flags)) {
5733                                 return 0;
5734                         }
5735                         count++;
5736                 }
5737         }
5738
5739         if (filter->dump_exceptions) {
5740                 struct fib6_nh_exception_dump_walker w = { .dump = arg,
5741                                                            .rt = rt,
5742                                                            .flags = flags,
5743                                                            .skip = skip,
5744                                                            .count = 0 };
5745                 int err;
5746
5747                 rcu_read_lock();
5748                 if (rt->nh) {
5749                         err = nexthop_for_each_fib6_nh(rt->nh,
5750                                                        rt6_nh_dump_exceptions,
5751                                                        &w);
5752                 } else {
5753                         err = rt6_nh_dump_exceptions(rt->fib6_nh, &w);
5754                 }
5755                 rcu_read_unlock();
5756
5757                 if (err)
5758                         return count += w.count;
5759         }
5760
5761         return -1;
5762 }
5763
5764 static int inet6_rtm_valid_getroute_req(struct sk_buff *skb,
5765                                         const struct nlmsghdr *nlh,
5766                                         struct nlattr **tb,
5767                                         struct netlink_ext_ack *extack)
5768 {
5769         struct rtmsg *rtm;
5770         int i, err;
5771
5772         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
5773                 NL_SET_ERR_MSG_MOD(extack,
5774                                    "Invalid header for get route request");
5775                 return -EINVAL;
5776         }
5777
5778         if (!netlink_strict_get_check(skb))
5779                 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
5780                                               rtm_ipv6_policy, extack);
5781
5782         rtm = nlmsg_data(nlh);
5783         if ((rtm->rtm_src_len && rtm->rtm_src_len != 128) ||
5784             (rtm->rtm_dst_len && rtm->rtm_dst_len != 128) ||
5785             rtm->rtm_table || rtm->rtm_protocol || rtm->rtm_scope ||
5786             rtm->rtm_type) {
5787                 NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for get route request");
5788                 return -EINVAL;
5789         }
5790         if (rtm->rtm_flags & ~RTM_F_FIB_MATCH) {
5791                 NL_SET_ERR_MSG_MOD(extack,
5792                                    "Invalid flags for get route request");
5793                 return -EINVAL;
5794         }
5795
5796         err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
5797                                             rtm_ipv6_policy, extack);
5798         if (err)
5799                 return err;
5800
5801         if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
5802             (tb[RTA_DST] && !rtm->rtm_dst_len)) {
5803                 NL_SET_ERR_MSG_MOD(extack, "rtm_src_len and rtm_dst_len must be 128 for IPv6");
5804                 return -EINVAL;
5805         }
5806
5807         for (i = 0; i <= RTA_MAX; i++) {
5808                 if (!tb[i])
5809                         continue;
5810
5811                 switch (i) {
5812                 case RTA_SRC:
5813                 case RTA_DST:
5814                 case RTA_IIF:
5815                 case RTA_OIF:
5816                 case RTA_MARK:
5817                 case RTA_UID:
5818                 case RTA_SPORT:
5819                 case RTA_DPORT:
5820                 case RTA_IP_PROTO:
5821                         break;
5822                 default:
5823                         NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in get route request");
5824                         return -EINVAL;
5825                 }
5826         }
5827
5828         return 0;
5829 }
5830
5831 static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
5832                               struct netlink_ext_ack *extack)
5833 {
5834         struct net *net = sock_net(in_skb->sk);
5835         struct nlattr *tb[RTA_MAX+1];
5836         int err, iif = 0, oif = 0;
5837         struct fib6_info *from;
5838         struct dst_entry *dst;
5839         struct rt6_info *rt;
5840         struct sk_buff *skb;
5841         struct rtmsg *rtm;
5842         struct flowi6 fl6 = {};
5843         bool fibmatch;
5844
5845         err = inet6_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
5846         if (err < 0)
5847                 goto errout;
5848
5849         err = -EINVAL;
5850         rtm = nlmsg_data(nlh);
5851         fl6.flowlabel = ip6_make_flowinfo(rtm->rtm_tos, 0);
5852         fibmatch = !!(rtm->rtm_flags & RTM_F_FIB_MATCH);
5853
5854         if (tb[RTA_SRC]) {
5855                 if (nla_len(tb[RTA_SRC]) < sizeof(struct in6_addr))
5856                         goto errout;
5857
5858                 fl6.saddr = *(struct in6_addr *)nla_data(tb[RTA_SRC]);
5859         }
5860
5861         if (tb[RTA_DST]) {
5862                 if (nla_len(tb[RTA_DST]) < sizeof(struct in6_addr))
5863                         goto errout;
5864
5865                 fl6.daddr = *(struct in6_addr *)nla_data(tb[RTA_DST]);
5866         }
5867
5868         if (tb[RTA_IIF])
5869                 iif = nla_get_u32(tb[RTA_IIF]);
5870
5871         if (tb[RTA_OIF])
5872                 oif = nla_get_u32(tb[RTA_OIF]);
5873
5874         if (tb[RTA_MARK])
5875                 fl6.flowi6_mark = nla_get_u32(tb[RTA_MARK]);
5876
5877         if (tb[RTA_UID])
5878                 fl6.flowi6_uid = make_kuid(current_user_ns(),
5879                                            nla_get_u32(tb[RTA_UID]));
5880         else
5881                 fl6.flowi6_uid = iif ? INVALID_UID : current_uid();
5882
5883         if (tb[RTA_SPORT])
5884                 fl6.fl6_sport = nla_get_be16(tb[RTA_SPORT]);
5885
5886         if (tb[RTA_DPORT])
5887                 fl6.fl6_dport = nla_get_be16(tb[RTA_DPORT]);
5888
5889         if (tb[RTA_IP_PROTO]) {
5890                 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
5891                                                   &fl6.flowi6_proto, AF_INET6,
5892                                                   extack);
5893                 if (err)
5894                         goto errout;
5895         }
5896
5897         if (iif) {
5898                 struct net_device *dev;
5899                 int flags = 0;
5900
5901                 rcu_read_lock();
5902
5903                 dev = dev_get_by_index_rcu(net, iif);
5904                 if (!dev) {
5905                         rcu_read_unlock();
5906                         err = -ENODEV;
5907                         goto errout;
5908                 }
5909
5910                 fl6.flowi6_iif = iif;
5911
5912                 if (!ipv6_addr_any(&fl6.saddr))
5913                         flags |= RT6_LOOKUP_F_HAS_SADDR;
5914
5915                 dst = ip6_route_input_lookup(net, dev, &fl6, NULL, flags);
5916
5917                 rcu_read_unlock();
5918         } else {
5919                 fl6.flowi6_oif = oif;
5920
5921                 dst = ip6_route_output(net, NULL, &fl6);
5922         }
5923
5924
5925         rt = container_of(dst, struct rt6_info, dst);
5926         if (rt->dst.error) {
5927                 err = rt->dst.error;
5928                 ip6_rt_put(rt);
5929                 goto errout;
5930         }
5931
5932         if (rt == net->ipv6.ip6_null_entry) {
5933                 err = rt->dst.error;
5934                 ip6_rt_put(rt);
5935                 goto errout;
5936         }
5937
5938         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
5939         if (!skb) {
5940                 ip6_rt_put(rt);
5941                 err = -ENOBUFS;
5942                 goto errout;
5943         }
5944
5945         skb_dst_set(skb, &rt->dst);
5946
5947         rcu_read_lock();
5948         from = rcu_dereference(rt->from);
5949         if (from) {
5950                 if (fibmatch)
5951                         err = rt6_fill_node(net, skb, from, NULL, NULL, NULL,
5952                                             iif, RTM_NEWROUTE,
5953                                             NETLINK_CB(in_skb).portid,
5954                                             nlh->nlmsg_seq, 0);
5955                 else
5956                         err = rt6_fill_node(net, skb, from, dst, &fl6.daddr,
5957                                             &fl6.saddr, iif, RTM_NEWROUTE,
5958                                             NETLINK_CB(in_skb).portid,
5959                                             nlh->nlmsg_seq, 0);
5960         } else {
5961                 err = -ENETUNREACH;
5962         }
5963         rcu_read_unlock();
5964
5965         if (err < 0) {
5966                 kfree_skb(skb);
5967                 goto errout;
5968         }
5969
5970         err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
5971 errout:
5972         return err;
5973 }
5974
5975 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
5976                      unsigned int nlm_flags)
5977 {
5978         struct sk_buff *skb;
5979         struct net *net = info->nl_net;
5980         u32 seq;
5981         int err;
5982
5983         err = -ENOBUFS;
5984         seq = info->nlh ? info->nlh->nlmsg_seq : 0;
5985
5986         skb = nlmsg_new(rt6_nlmsg_size(rt), gfp_any());
5987         if (!skb)
5988                 goto errout;
5989
5990         err = rt6_fill_node(net, skb, rt, NULL, NULL, NULL, 0,
5991                             event, info->portid, seq, nlm_flags);
5992         if (err < 0) {
5993                 /* -EMSGSIZE implies BUG in rt6_nlmsg_size() */
5994                 WARN_ON(err == -EMSGSIZE);
5995                 kfree_skb(skb);
5996                 goto errout;
5997         }
5998         rtnl_notify(skb, net, info->portid, RTNLGRP_IPV6_ROUTE,
5999                     info->nlh, gfp_any());
6000         return;
6001 errout:
6002         if (err < 0)
6003                 rtnl_set_sk_err(net, RTNLGRP_IPV6_ROUTE, err);
6004 }
6005
6006 void fib6_rt_update(struct net *net, struct fib6_info *rt,
6007                     struct nl_info *info)
6008 {
6009         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
6010         struct sk_buff *skb;
6011         int err = -ENOBUFS;
6012
6013         /* call_fib6_entry_notifiers will be removed when in-kernel notifier
6014          * is implemented and supported for nexthop objects
6015          */
6016         call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE, rt, NULL);
6017
6018         skb = nlmsg_new(rt6_nlmsg_size(rt), gfp_any());
6019         if (!skb)
6020                 goto errout;
6021
6022         err = rt6_fill_node(net, skb, rt, NULL, NULL, NULL, 0,
6023                             RTM_NEWROUTE, info->portid, seq, NLM_F_REPLACE);
6024         if (err < 0) {
6025                 /* -EMSGSIZE implies BUG in rt6_nlmsg_size() */
6026                 WARN_ON(err == -EMSGSIZE);
6027                 kfree_skb(skb);
6028                 goto errout;
6029         }
6030         rtnl_notify(skb, net, info->portid, RTNLGRP_IPV6_ROUTE,
6031                     info->nlh, gfp_any());
6032         return;
6033 errout:
6034         if (err < 0)
6035                 rtnl_set_sk_err(net, RTNLGRP_IPV6_ROUTE, err);
6036 }
6037
6038 static int ip6_route_dev_notify(struct notifier_block *this,
6039                                 unsigned long event, void *ptr)
6040 {
6041         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
6042         struct net *net = dev_net(dev);
6043
6044         if (!(dev->flags & IFF_LOOPBACK))
6045                 return NOTIFY_OK;
6046
6047         if (event == NETDEV_REGISTER) {
6048                 net->ipv6.fib6_null_entry->fib6_nh->fib_nh_dev = dev;
6049                 net->ipv6.ip6_null_entry->dst.dev = dev;
6050                 net->ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(dev);
6051 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
6052                 net->ipv6.ip6_prohibit_entry->dst.dev = dev;
6053                 net->ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(dev);
6054                 net->ipv6.ip6_blk_hole_entry->dst.dev = dev;
6055                 net->ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(dev);
6056 #endif
6057          } else if (event == NETDEV_UNREGISTER &&
6058                     dev->reg_state != NETREG_UNREGISTERED) {
6059                 /* NETDEV_UNREGISTER could be fired for multiple times by
6060                  * netdev_wait_allrefs(). Make sure we only call this once.
6061                  */
6062                 in6_dev_put_clear(&net->ipv6.ip6_null_entry->rt6i_idev);
6063 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
6064                 in6_dev_put_clear(&net->ipv6.ip6_prohibit_entry->rt6i_idev);
6065                 in6_dev_put_clear(&net->ipv6.ip6_blk_hole_entry->rt6i_idev);
6066 #endif
6067         }
6068
6069         return NOTIFY_OK;
6070 }
6071
6072 /*
6073  *      /proc
6074  */
6075
6076 #ifdef CONFIG_PROC_FS
6077 static int rt6_stats_seq_show(struct seq_file *seq, void *v)
6078 {
6079         struct net *net = (struct net *)seq->private;
6080         seq_printf(seq, "%04x %04x %04x %04x %04x %04x %04x\n",
6081                    net->ipv6.rt6_stats->fib_nodes,
6082                    net->ipv6.rt6_stats->fib_route_nodes,
6083                    atomic_read(&net->ipv6.rt6_stats->fib_rt_alloc),
6084                    net->ipv6.rt6_stats->fib_rt_entries,
6085                    net->ipv6.rt6_stats->fib_rt_cache,
6086                    dst_entries_get_slow(&net->ipv6.ip6_dst_ops),
6087                    net->ipv6.rt6_stats->fib_discarded_routes);
6088
6089         return 0;
6090 }
6091 #endif  /* CONFIG_PROC_FS */
6092
6093 #ifdef CONFIG_SYSCTL
6094
6095 static int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write,
6096                               void *buffer, size_t *lenp, loff_t *ppos)
6097 {
6098         struct net *net;
6099         int delay;
6100         int ret;
6101         if (!write)
6102                 return -EINVAL;
6103
6104         net = (struct net *)ctl->extra1;
6105         delay = net->ipv6.sysctl.flush_delay;
6106         ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
6107         if (ret)
6108                 return ret;
6109
6110         fib6_run_gc(delay <= 0 ? 0 : (unsigned long)delay, net, delay > 0);
6111         return 0;
6112 }
6113
6114 static struct ctl_table ipv6_route_table_template[] = {
6115         {
6116                 .procname       =       "flush",
6117                 .data           =       &init_net.ipv6.sysctl.flush_delay,
6118                 .maxlen         =       sizeof(int),
6119                 .mode           =       0200,
6120                 .proc_handler   =       ipv6_sysctl_rtcache_flush
6121         },
6122         {
6123                 .procname       =       "gc_thresh",
6124                 .data           =       &ip6_dst_ops_template.gc_thresh,
6125                 .maxlen         =       sizeof(int),
6126                 .mode           =       0644,
6127                 .proc_handler   =       proc_dointvec,
6128         },
6129         {
6130                 .procname       =       "max_size",
6131                 .data           =       &init_net.ipv6.sysctl.ip6_rt_max_size,
6132                 .maxlen         =       sizeof(int),
6133                 .mode           =       0644,
6134                 .proc_handler   =       proc_dointvec,
6135         },
6136         {
6137                 .procname       =       "gc_min_interval",
6138                 .data           =       &init_net.ipv6.sysctl.ip6_rt_gc_min_interval,
6139                 .maxlen         =       sizeof(int),
6140                 .mode           =       0644,
6141                 .proc_handler   =       proc_dointvec_jiffies,
6142         },
6143         {
6144                 .procname       =       "gc_timeout",
6145                 .data           =       &init_net.ipv6.sysctl.ip6_rt_gc_timeout,
6146                 .maxlen         =       sizeof(int),
6147                 .mode           =       0644,
6148                 .proc_handler   =       proc_dointvec_jiffies,
6149         },
6150         {
6151                 .procname       =       "gc_interval",
6152                 .data           =       &init_net.ipv6.sysctl.ip6_rt_gc_interval,
6153                 .maxlen         =       sizeof(int),
6154                 .mode           =       0644,
6155                 .proc_handler   =       proc_dointvec_jiffies,
6156         },
6157         {
6158                 .procname       =       "gc_elasticity",
6159                 .data           =       &init_net.ipv6.sysctl.ip6_rt_gc_elasticity,
6160                 .maxlen         =       sizeof(int),
6161                 .mode           =       0644,
6162                 .proc_handler   =       proc_dointvec,
6163         },
6164         {
6165                 .procname       =       "mtu_expires",
6166                 .data           =       &init_net.ipv6.sysctl.ip6_rt_mtu_expires,
6167                 .maxlen         =       sizeof(int),
6168                 .mode           =       0644,
6169                 .proc_handler   =       proc_dointvec_jiffies,
6170         },
6171         {
6172                 .procname       =       "min_adv_mss",
6173                 .data           =       &init_net.ipv6.sysctl.ip6_rt_min_advmss,
6174                 .maxlen         =       sizeof(int),
6175                 .mode           =       0644,
6176                 .proc_handler   =       proc_dointvec,
6177         },
6178         {
6179                 .procname       =       "gc_min_interval_ms",
6180                 .data           =       &init_net.ipv6.sysctl.ip6_rt_gc_min_interval,
6181                 .maxlen         =       sizeof(int),
6182                 .mode           =       0644,
6183                 .proc_handler   =       proc_dointvec_ms_jiffies,
6184         },
6185         {
6186                 .procname       =       "skip_notify_on_dev_down",
6187                 .data           =       &init_net.ipv6.sysctl.skip_notify_on_dev_down,
6188                 .maxlen         =       sizeof(int),
6189                 .mode           =       0644,
6190                 .proc_handler   =       proc_dointvec_minmax,
6191                 .extra1         =       SYSCTL_ZERO,
6192                 .extra2         =       SYSCTL_ONE,
6193         },
6194         { }
6195 };
6196
6197 struct ctl_table * __net_init ipv6_route_sysctl_init(struct net *net)
6198 {
6199         struct ctl_table *table;
6200
6201         table = kmemdup(ipv6_route_table_template,
6202                         sizeof(ipv6_route_table_template),
6203                         GFP_KERNEL);
6204
6205         if (table) {
6206                 table[0].data = &net->ipv6.sysctl.flush_delay;
6207                 table[0].extra1 = net;
6208                 table[1].data = &net->ipv6.ip6_dst_ops.gc_thresh;
6209                 table[2].data = &net->ipv6.sysctl.ip6_rt_max_size;
6210                 table[3].data = &net->ipv6.sysctl.ip6_rt_gc_min_interval;
6211                 table[4].data = &net->ipv6.sysctl.ip6_rt_gc_timeout;
6212                 table[5].data = &net->ipv6.sysctl.ip6_rt_gc_interval;
6213                 table[6].data = &net->ipv6.sysctl.ip6_rt_gc_elasticity;
6214                 table[7].data = &net->ipv6.sysctl.ip6_rt_mtu_expires;
6215                 table[8].data = &net->ipv6.sysctl.ip6_rt_min_advmss;
6216                 table[9].data = &net->ipv6.sysctl.ip6_rt_gc_min_interval;
6217                 table[10].data = &net->ipv6.sysctl.skip_notify_on_dev_down;
6218
6219                 /* Don't export sysctls to unprivileged users */
6220                 if (net->user_ns != &init_user_ns)
6221                         table[0].procname = NULL;
6222         }
6223
6224         return table;
6225 }
6226 #endif
6227
6228 static int __net_init ip6_route_net_init(struct net *net)
6229 {
6230         int ret = -ENOMEM;
6231
6232         memcpy(&net->ipv6.ip6_dst_ops, &ip6_dst_ops_template,
6233                sizeof(net->ipv6.ip6_dst_ops));
6234
6235         if (dst_entries_init(&net->ipv6.ip6_dst_ops) < 0)
6236                 goto out_ip6_dst_ops;
6237
6238         net->ipv6.fib6_null_entry = fib6_info_alloc(GFP_KERNEL, true);
6239         if (!net->ipv6.fib6_null_entry)
6240                 goto out_ip6_dst_entries;
6241         memcpy(net->ipv6.fib6_null_entry, &fib6_null_entry_template,
6242                sizeof(*net->ipv6.fib6_null_entry));
6243
6244         net->ipv6.ip6_null_entry = kmemdup(&ip6_null_entry_template,
6245                                            sizeof(*net->ipv6.ip6_null_entry),
6246                                            GFP_KERNEL);
6247         if (!net->ipv6.ip6_null_entry)
6248                 goto out_fib6_null_entry;
6249         net->ipv6.ip6_null_entry->dst.ops = &net->ipv6.ip6_dst_ops;
6250         dst_init_metrics(&net->ipv6.ip6_null_entry->dst,
6251                          ip6_template_metrics, true);
6252         INIT_LIST_HEAD(&net->ipv6.ip6_null_entry->rt6i_uncached);
6253
6254 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
6255         net->ipv6.fib6_has_custom_rules = false;
6256         net->ipv6.ip6_prohibit_entry = kmemdup(&ip6_prohibit_entry_template,
6257                                                sizeof(*net->ipv6.ip6_prohibit_entry),
6258                                                GFP_KERNEL);
6259         if (!net->ipv6.ip6_prohibit_entry)
6260                 goto out_ip6_null_entry;
6261         net->ipv6.ip6_prohibit_entry->dst.ops = &net->ipv6.ip6_dst_ops;
6262         dst_init_metrics(&net->ipv6.ip6_prohibit_entry->dst,
6263                          ip6_template_metrics, true);
6264         INIT_LIST_HEAD(&net->ipv6.ip6_prohibit_entry->rt6i_uncached);
6265
6266         net->ipv6.ip6_blk_hole_entry = kmemdup(&ip6_blk_hole_entry_template,
6267                                                sizeof(*net->ipv6.ip6_blk_hole_entry),
6268                                                GFP_KERNEL);
6269         if (!net->ipv6.ip6_blk_hole_entry)
6270                 goto out_ip6_prohibit_entry;
6271         net->ipv6.ip6_blk_hole_entry->dst.ops = &net->ipv6.ip6_dst_ops;
6272         dst_init_metrics(&net->ipv6.ip6_blk_hole_entry->dst,
6273                          ip6_template_metrics, true);
6274         INIT_LIST_HEAD(&net->ipv6.ip6_blk_hole_entry->rt6i_uncached);
6275 #ifdef CONFIG_IPV6_SUBTREES
6276         net->ipv6.fib6_routes_require_src = 0;
6277 #endif
6278 #endif
6279
6280         net->ipv6.sysctl.flush_delay = 0;
6281         net->ipv6.sysctl.ip6_rt_max_size = 4096;
6282         net->ipv6.sysctl.ip6_rt_gc_min_interval = HZ / 2;
6283         net->ipv6.sysctl.ip6_rt_gc_timeout = 60*HZ;
6284         net->ipv6.sysctl.ip6_rt_gc_interval = 30*HZ;
6285         net->ipv6.sysctl.ip6_rt_gc_elasticity = 9;
6286         net->ipv6.sysctl.ip6_rt_mtu_expires = 10*60*HZ;
6287         net->ipv6.sysctl.ip6_rt_min_advmss = IPV6_MIN_MTU - 20 - 40;
6288         net->ipv6.sysctl.skip_notify_on_dev_down = 0;
6289
6290         net->ipv6.ip6_rt_gc_expire = 30*HZ;
6291
6292         ret = 0;
6293 out:
6294         return ret;
6295
6296 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
6297 out_ip6_prohibit_entry:
6298         kfree(net->ipv6.ip6_prohibit_entry);
6299 out_ip6_null_entry:
6300         kfree(net->ipv6.ip6_null_entry);
6301 #endif
6302 out_fib6_null_entry:
6303         kfree(net->ipv6.fib6_null_entry);
6304 out_ip6_dst_entries:
6305         dst_entries_destroy(&net->ipv6.ip6_dst_ops);
6306 out_ip6_dst_ops:
6307         goto out;
6308 }
6309
6310 static void __net_exit ip6_route_net_exit(struct net *net)
6311 {
6312         kfree(net->ipv6.fib6_null_entry);
6313         kfree(net->ipv6.ip6_null_entry);
6314 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
6315         kfree(net->ipv6.ip6_prohibit_entry);
6316         kfree(net->ipv6.ip6_blk_hole_entry);
6317 #endif
6318         dst_entries_destroy(&net->ipv6.ip6_dst_ops);
6319 }
6320
6321 static int __net_init ip6_route_net_init_late(struct net *net)
6322 {
6323 #ifdef CONFIG_PROC_FS
6324         proc_create_net("ipv6_route", 0, net->proc_net, &ipv6_route_seq_ops,
6325                         sizeof(struct ipv6_route_iter));
6326         proc_create_net_single("rt6_stats", 0444, net->proc_net,
6327                         rt6_stats_seq_show, NULL);
6328 #endif
6329         return 0;
6330 }
6331
6332 static void __net_exit ip6_route_net_exit_late(struct net *net)
6333 {
6334 #ifdef CONFIG_PROC_FS
6335         remove_proc_entry("ipv6_route", net->proc_net);
6336         remove_proc_entry("rt6_stats", net->proc_net);
6337 #endif
6338 }
6339
6340 static struct pernet_operations ip6_route_net_ops = {
6341         .init = ip6_route_net_init,
6342         .exit = ip6_route_net_exit,
6343 };
6344
6345 static int __net_init ipv6_inetpeer_init(struct net *net)
6346 {
6347         struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
6348
6349         if (!bp)
6350                 return -ENOMEM;
6351         inet_peer_base_init(bp);
6352         net->ipv6.peers = bp;
6353         return 0;
6354 }
6355
6356 static void __net_exit ipv6_inetpeer_exit(struct net *net)
6357 {
6358         struct inet_peer_base *bp = net->ipv6.peers;
6359
6360         net->ipv6.peers = NULL;
6361         inetpeer_invalidate_tree(bp);
6362         kfree(bp);
6363 }
6364
6365 static struct pernet_operations ipv6_inetpeer_ops = {
6366         .init   =       ipv6_inetpeer_init,
6367         .exit   =       ipv6_inetpeer_exit,
6368 };
6369
6370 static struct pernet_operations ip6_route_net_late_ops = {
6371         .init = ip6_route_net_init_late,
6372         .exit = ip6_route_net_exit_late,
6373 };
6374
6375 static struct notifier_block ip6_route_dev_notifier = {
6376         .notifier_call = ip6_route_dev_notify,
6377         .priority = ADDRCONF_NOTIFY_PRIORITY - 10,
6378 };
6379
6380 void __init ip6_route_init_special_entries(void)
6381 {
6382         /* Registering of the loopback is done before this portion of code,
6383          * the loopback reference in rt6_info will not be taken, do it
6384          * manually for init_net */
6385         init_net.ipv6.fib6_null_entry->fib6_nh->fib_nh_dev = init_net.loopback_dev;
6386         init_net.ipv6.ip6_null_entry->dst.dev = init_net.loopback_dev;
6387         init_net.ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
6388   #ifdef CONFIG_IPV6_MULTIPLE_TABLES
6389         init_net.ipv6.ip6_prohibit_entry->dst.dev = init_net.loopback_dev;
6390         init_net.ipv6.ip6_prohibit_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
6391         init_net.ipv6.ip6_blk_hole_entry->dst.dev = init_net.loopback_dev;
6392         init_net.ipv6.ip6_blk_hole_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
6393   #endif
6394 }
6395
6396 #if IS_BUILTIN(CONFIG_IPV6)
6397 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
6398 DEFINE_BPF_ITER_FUNC(ipv6_route, struct bpf_iter_meta *meta, struct fib6_info *rt)
6399
6400 static int __init bpf_iter_register(void)
6401 {
6402         struct bpf_iter_reg reg_info = {
6403                 .target                 = "ipv6_route",
6404                 .seq_ops                = &ipv6_route_seq_ops,
6405                 .init_seq_private       = bpf_iter_init_seq_net,
6406                 .fini_seq_private       = bpf_iter_fini_seq_net,
6407                 .seq_priv_size          = sizeof(struct ipv6_route_iter),
6408         };
6409
6410         return bpf_iter_reg_target(&reg_info);
6411 }
6412
6413 static void bpf_iter_unregister(void)
6414 {
6415         bpf_iter_unreg_target("ipv6_route");
6416 }
6417 #endif
6418 #endif
6419
6420 int __init ip6_route_init(void)
6421 {
6422         int ret;
6423         int cpu;
6424
6425         ret = -ENOMEM;
6426         ip6_dst_ops_template.kmem_cachep =
6427                 kmem_cache_create("ip6_dst_cache", sizeof(struct rt6_info), 0,
6428                                   SLAB_HWCACHE_ALIGN, NULL);
6429         if (!ip6_dst_ops_template.kmem_cachep)
6430                 goto out;
6431
6432         ret = dst_entries_init(&ip6_dst_blackhole_ops);
6433         if (ret)
6434                 goto out_kmem_cache;
6435
6436         ret = register_pernet_subsys(&ipv6_inetpeer_ops);
6437         if (ret)
6438                 goto out_dst_entries;
6439
6440         ret = register_pernet_subsys(&ip6_route_net_ops);
6441         if (ret)
6442                 goto out_register_inetpeer;
6443
6444         ip6_dst_blackhole_ops.kmem_cachep = ip6_dst_ops_template.kmem_cachep;
6445
6446         ret = fib6_init();
6447         if (ret)
6448                 goto out_register_subsys;
6449
6450         ret = xfrm6_init();
6451         if (ret)
6452                 goto out_fib6_init;
6453
6454         ret = fib6_rules_init();
6455         if (ret)
6456                 goto xfrm6_init;
6457
6458         ret = register_pernet_subsys(&ip6_route_net_late_ops);
6459         if (ret)
6460                 goto fib6_rules_init;
6461
6462         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_NEWROUTE,
6463                                    inet6_rtm_newroute, NULL, 0);
6464         if (ret < 0)
6465                 goto out_register_late_subsys;
6466
6467         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_DELROUTE,
6468                                    inet6_rtm_delroute, NULL, 0);
6469         if (ret < 0)
6470                 goto out_register_late_subsys;
6471
6472         ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE,
6473                                    inet6_rtm_getroute, NULL,
6474                                    RTNL_FLAG_DOIT_UNLOCKED);
6475         if (ret < 0)
6476                 goto out_register_late_subsys;
6477
6478         ret = register_netdevice_notifier(&ip6_route_dev_notifier);
6479         if (ret)
6480                 goto out_register_late_subsys;
6481
6482 #if IS_BUILTIN(CONFIG_IPV6)
6483 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
6484         ret = bpf_iter_register();
6485         if (ret)
6486                 goto out_register_late_subsys;
6487 #endif
6488 #endif
6489
6490         for_each_possible_cpu(cpu) {
6491                 struct uncached_list *ul = per_cpu_ptr(&rt6_uncached_list, cpu);
6492
6493                 INIT_LIST_HEAD(&ul->head);
6494                 spin_lock_init(&ul->lock);
6495         }
6496
6497 out:
6498         return ret;
6499
6500 out_register_late_subsys:
6501         rtnl_unregister_all(PF_INET6);
6502         unregister_pernet_subsys(&ip6_route_net_late_ops);
6503 fib6_rules_init:
6504         fib6_rules_cleanup();
6505 xfrm6_init:
6506         xfrm6_fini();
6507 out_fib6_init:
6508         fib6_gc_cleanup();
6509 out_register_subsys:
6510         unregister_pernet_subsys(&ip6_route_net_ops);
6511 out_register_inetpeer:
6512         unregister_pernet_subsys(&ipv6_inetpeer_ops);
6513 out_dst_entries:
6514         dst_entries_destroy(&ip6_dst_blackhole_ops);
6515 out_kmem_cache:
6516         kmem_cache_destroy(ip6_dst_ops_template.kmem_cachep);
6517         goto out;
6518 }
6519
6520 void ip6_route_cleanup(void)
6521 {
6522 #if IS_BUILTIN(CONFIG_IPV6)
6523 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
6524         bpf_iter_unregister();
6525 #endif
6526 #endif
6527         unregister_netdevice_notifier(&ip6_route_dev_notifier);
6528         unregister_pernet_subsys(&ip6_route_net_late_ops);
6529         fib6_rules_cleanup();
6530         xfrm6_fini();
6531         fib6_gc_cleanup();
6532         unregister_pernet_subsys(&ipv6_inetpeer_ops);
6533         unregister_pernet_subsys(&ip6_route_net_ops);
6534         dst_entries_destroy(&ip6_dst_blackhole_ops);
6535         kmem_cache_destroy(ip6_dst_ops_template.kmem_cachep);
6536 }