net/ipv4/fib_frontend.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              IPv4 Forwarding Information Base: FIB frontend.
   7  *
   8  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   9  *
  10  *              This program is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <asm/uaccess.h>
  18 #include <linux/bitops.h>
  19 #include <linux/capability.h>
  20 #include <linux/types.h>
  21 #include <linux/kernel.h>
  22 #include <linux/mm.h>
  23 #include <linux/string.h>
  24 #include <linux/socket.h>
  25 #include <linux/sockios.h>
  26 #include <linux/errno.h>
  27 #include <linux/in.h>
  28 #include <linux/inet.h>
  29 #include <linux/inetdevice.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/if_addr.h>
  32 #include <linux/if_arp.h>
  33 #include <linux/skbuff.h>
  34 #include <linux/cache.h>
  35 #include <linux/init.h>
  36 #include <linux/list.h>
  37 #include <linux/slab.h>
  38
  39 #include <net/ip.h>
  40 #include <net/protocol.h>
  41 #include <net/route.h>
  42 #include <net/tcp.h>
  43 #include <net/sock.h>
  44 #include <net/arp.h>
  45 #include <net/ip_fib.h>
  46 #include <net/rtnetlink.h>
  47 #include <net/xfrm.h>
  48
  49 #ifndef CONFIG_IP_MULTIPLE_TABLES
  50
  51 static int __net_init fib4_rules_init(struct net *net)
  52 {
  53         struct fib_table *local_table, *main_table;
  54
  55         local_table = fib_trie_table(RT_TABLE_LOCAL);
  56         if (local_table == NULL)
  57                 return -ENOMEM;
  58
  59         main_table  = fib_trie_table(RT_TABLE_MAIN);
  60         if (main_table == NULL)
  61                 goto fail;
  62
  63         hlist_add_head_rcu(&local_table->tb_hlist,
  64                                 &net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
  65         hlist_add_head_rcu(&main_table->tb_hlist,
  66                                 &net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
  67         return 0;
  68
  69 fail:
  70         kfree(local_table);
  71         return -ENOMEM;
  72 }
  73 #else
  74
  75 struct fib_table *fib_new_table(struct net *net, u32 id)
  76 {
  77         struct fib_table *tb;
  78         unsigned int h;
  79
  80         if (id == 0)
  81                 id = RT_TABLE_MAIN;
  82         tb = fib_get_table(net, id);
  83         if (tb)
  84                 return tb;
  85
  86         tb = fib_trie_table(id);
  87         if (!tb)
  88                 return NULL;
  89
  90         switch (id) {
  91         case RT_TABLE_LOCAL:
  92                 net->ipv4.fib_local = tb;
  93                 break;
  94
  95         case RT_TABLE_MAIN:
  96                 net->ipv4.fib_main = tb;
  97                 break;
  98
  99         case RT_TABLE_DEFAULT:
 100                 net->ipv4.fib_default = tb;
 101                 break;
 102
 103         default:
 104                 break;
 105         }
 106
 107         h = id & (FIB_TABLE_HASHSZ - 1);
 108         hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
 109         return tb;
 110 }
 111
 112 struct fib_table *fib_get_table(struct net *net, u32 id)
 113 {
 114         struct fib_table *tb;
 115         struct hlist_head *head;
 116         unsigned int h;
 117
 118         if (id == 0)
 119                 id = RT_TABLE_MAIN;
 120         h = id & (FIB_TABLE_HASHSZ - 1);
 121
 122         rcu_read_lock();
 123         head = &net->ipv4.fib_table_hash[h];
 124         hlist_for_each_entry_rcu(tb, head, tb_hlist) {
 125                 if (tb->tb_id == id) {
 126                         rcu_read_unlock();
 127                         return tb;
 128                 }
 129         }
 130         rcu_read_unlock();
 131         return NULL;
 132 }
 133 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 134
 135 static void fib_flush(struct net *net)
 136 {
 137         int flushed = 0;
 138         struct fib_table *tb;
 139         struct hlist_head *head;
 140         unsigned int h;
 141
 142         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
 143                 head = &net->ipv4.fib_table_hash[h];
 144                 hlist_for_each_entry(tb, head, tb_hlist)
 145                         flushed += fib_table_flush(tb);
 146         }
 147
 148         if (flushed)
 149                 rt_cache_flush(net);
 150 }
 151
 152 /*
 153  * Find address type as if only "dev" was present in the system. If
 154  * on_dev is NULL then all interfaces are taken into consideration.
 155  */
 156 static inline unsigned int __inet_dev_addr_type(struct net *net,
 157                                                 const struct net_device *dev,
 158                                                 __be32 addr)
 159 {
 160         struct flowi4           fl4 = { .daddr = addr };
 161         struct fib_result       res;
 162         unsigned int ret = RTN_BROADCAST;
 163         struct fib_table *local_table;
 164
 165         if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
 166                 return RTN_BROADCAST;
 167         if (ipv4_is_multicast(addr))
 168                 return RTN_MULTICAST;
 169
 170         local_table = fib_get_table(net, RT_TABLE_LOCAL);
 171         if (local_table) {
 172                 ret = RTN_UNICAST;
 173                 rcu_read_lock();
 174                 if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) {
 175                         if (!dev || dev == res.fi->fib_dev)
 176                                 ret = res.type;
 177                 }
 178                 rcu_read_unlock();
 179         }
 180         return ret;
 181 }
 182
 183 unsigned int inet_addr_type(struct net *net, __be32 addr)
 184 {
 185         return __inet_dev_addr_type(net, NULL, addr);
 186 }
 187 EXPORT_SYMBOL(inet_addr_type);
 188
 189 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
 190                                 __be32 addr)
 191 {
 192         return __inet_dev_addr_type(net, dev, addr);
 193 }
 194 EXPORT_SYMBOL(inet_dev_addr_type);
 195
 196 __be32 fib_compute_spec_dst(struct sk_buff *skb)
 197 {
 198         struct net_device *dev = skb->dev;
 199         struct in_device *in_dev;
 200         struct fib_result res;
 201         struct rtable *rt;
 202         struct flowi4 fl4;
 203         struct net *net;
 204         int scope;
 205
 206         rt = skb_rtable(skb);
 207         if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
 208             RTCF_LOCAL)
 209                 return ip_hdr(skb)->daddr;
 210
 211         in_dev = __in_dev_get_rcu(dev);
 212         BUG_ON(!in_dev);
 213
 214         net = dev_net(dev);
 215
 216         scope = RT_SCOPE_UNIVERSE;
 217         if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
 218                 fl4.flowi4_oif = 0;
 219                 fl4.flowi4_iif = LOOPBACK_IFINDEX;
 220                 fl4.daddr = ip_hdr(skb)->saddr;
 221                 fl4.saddr = 0;
 222                 fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
 223                 fl4.flowi4_scope = scope;
 224                 fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
 225                 if (!fib_lookup(net, &fl4, &res))
 226                         return FIB_RES_PREFSRC(net, res);
 227         } else {
 228                 scope = RT_SCOPE_LINK;
 229         }
 230
 231         return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
 232 }
 233
 234 /* Given (packet source, input interface) and optional (dst, oif, tos):
 235  * - (main) check, that source is valid i.e. not broadcast or our local
 236  *   address.
 237  * - figure out what "logical" interface this packet arrived
 238  *   and calculate "specific destination" address.
 239  * - check, that packet arrived from expected physical interface.
 240  * called with rcu_read_lock()
 241  */
 242 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 243                                  u8 tos, int oif, struct net_device *dev,
 244                                  int rpf, struct in_device *idev, u32 *itag)
 245 {
 246         int ret, no_addr, accept_local;
 247         struct fib_result res;
 248         struct flowi4 fl4;
 249         struct net *net;
 250         bool dev_match;
 251
 252         fl4.flowi4_oif = 0;
 253         fl4.flowi4_iif = oif;
 254         fl4.daddr = src;
 255         fl4.saddr = dst;
 256         fl4.flowi4_tos = tos;
 257         fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
 258
 259         no_addr = idev->ifa_list == NULL;
 260
 261         accept_local = IN_DEV_ACCEPT_LOCAL(idev);
 262         fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
 263
 264         net = dev_net(dev);
 265         if (fib_lookup(net, &fl4, &res))
 266                 goto last_resort;
 267         if (res.type != RTN_UNICAST) {
 268                 if (res.type != RTN_LOCAL || !accept_local)
 269                         goto e_inval;
 270         }
 271         fib_combine_itag(itag, &res);
 272         dev_match = false;
 273
 274 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 275         for (ret = 0; ret < res.fi->fib_nhs; ret++) {
 276                 struct fib_nh *nh = &res.fi->fib_nh[ret];
 277
 278                 if (nh->nh_dev == dev) {
 279                         dev_match = true;
 280                         break;
 281                 }
 282         }
 283 #else
 284         if (FIB_RES_DEV(res) == dev)
 285                 dev_match = true;
 286 #endif
 287         if (dev_match) {
 288                 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 289                 return ret;
 290         }
 291         if (no_addr)
 292                 goto last_resort;
 293         if (rpf == 1)
 294                 goto e_rpf;
 295         fl4.flowi4_oif = dev->ifindex;
 296
 297         ret = 0;
 298         if (fib_lookup(net, &fl4, &res) == 0) {
 299                 if (res.type == RTN_UNICAST)
 300                         ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
 301         }
 302         return ret;
 303
 304 last_resort:
 305         if (rpf)
 306                 goto e_rpf;
 307         *itag = 0;
 308         return 0;
 309
 310 e_inval:
 311         return -EINVAL;
 312 e_rpf:
 313         return -EXDEV;
 314 }
 315
 316 /* Ignore rp_filter for packets protected by IPsec. */
 317 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 318                         u8 tos, int oif, struct net_device *dev,
 319                         struct in_device *idev, u32 *itag)
 320 {
 321         int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
 322
 323         if (!r && !fib_num_tclassid_users(dev_net(dev)) &&
 324             (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
 325                 *itag = 0;
 326                 return 0;
 327         }
 328         return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
 329 }
 330
 331 static inline __be32 sk_extract_addr(struct sockaddr *addr)
 332 {
 333         return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
 334 }
 335
 336 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
 337 {
 338         struct nlattr *nla;
 339
 340         nla = (struct nlattr *) ((char *) mx + len);
 341         nla->nla_type = type;
 342         nla->nla_len = nla_attr_size(4);
 343         *(u32 *) nla_data(nla) = value;
 344
 345         return len + nla_total_size(4);
 346 }
 347
 348 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 349                                  struct fib_config *cfg)
 350 {
 351         __be32 addr;
 352         int plen;
 353
 354         memset(cfg, 0, sizeof(*cfg));
 355         cfg->fc_nlinfo.nl_net = net;
 356
 357         if (rt->rt_dst.sa_family != AF_INET)
 358                 return -EAFNOSUPPORT;
 359
 360         /*
 361          * Check mask for validity:
 362          * a) it must be contiguous.
 363          * b) destination must have all host bits clear.
 364          * c) if application forgot to set correct family (AF_INET),
 365          *    reject request unless it is absolutely clear i.e.
 366          *    both family and mask are zero.
 367          */
 368         plen = 32;
 369         addr = sk_extract_addr(&rt->rt_dst);
 370         if (!(rt->rt_flags & RTF_HOST)) {
 371                 __be32 mask = sk_extract_addr(&rt->rt_genmask);
 372
 373                 if (rt->rt_genmask.sa_family != AF_INET) {
 374                         if (mask || rt->rt_genmask.sa_family)
 375                                 return -EAFNOSUPPORT;
 376                 }
 377
 378                 if (bad_mask(mask, addr))
 379                         return -EINVAL;
 380
 381                 plen = inet_mask_len(mask);
 382         }
 383
 384         cfg->fc_dst_len = plen;
 385         cfg->fc_dst = addr;
 386
 387         if (cmd != SIOCDELRT) {
 388                 cfg->fc_nlflags = NLM_F_CREATE;
 389                 cfg->fc_protocol = RTPROT_BOOT;
 390         }
 391
 392         if (rt->rt_metric)
 393                 cfg->fc_priority = rt->rt_metric - 1;
 394
 395         if (rt->rt_flags & RTF_REJECT) {
 396                 cfg->fc_scope = RT_SCOPE_HOST;
 397                 cfg->fc_type = RTN_UNREACHABLE;
 398                 return 0;
 399         }
 400
 401         cfg->fc_scope = RT_SCOPE_NOWHERE;
 402         cfg->fc_type = RTN_UNICAST;
 403
 404         if (rt->rt_dev) {
 405                 char *colon;
 406                 struct net_device *dev;
 407                 char devname[IFNAMSIZ];
 408
 409                 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
 410                         return -EFAULT;
 411
 412                 devname[IFNAMSIZ-1] = 0;
 413                 colon = strchr(devname, ':');
 414                 if (colon)
 415                         *colon = 0;
 416                 dev = __dev_get_by_name(net, devname);
 417                 if (!dev)
 418                         return -ENODEV;
 419                 cfg->fc_oif = dev->ifindex;
 420                 if (colon) {
 421                         struct in_ifaddr *ifa;
 422                         struct in_device *in_dev = __in_dev_get_rtnl(dev);
 423                         if (!in_dev)
 424                                 return -ENODEV;
 425                         *colon = ':';
 426                         for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
 427                                 if (strcmp(ifa->ifa_label, devname) == 0)
 428                                         break;
 429                         if (ifa == NULL)
 430                                 return -ENODEV;
 431                         cfg->fc_prefsrc = ifa->ifa_local;
 432                 }
 433         }
 434
 435         addr = sk_extract_addr(&rt->rt_gateway);
 436         if (rt->rt_gateway.sa_family == AF_INET && addr) {
 437                 cfg->fc_gw = addr;
 438                 if (rt->rt_flags & RTF_GATEWAY &&
 439                     inet_addr_type(net, addr) == RTN_UNICAST)
 440                         cfg->fc_scope = RT_SCOPE_UNIVERSE;
 441         }
 442
 443         if (cmd == SIOCDELRT)
 444                 return 0;
 445
 446         if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
 447                 return -EINVAL;
 448
 449         if (cfg->fc_scope == RT_SCOPE_NOWHERE)
 450                 cfg->fc_scope = RT_SCOPE_LINK;
 451
 452         if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
 453                 struct nlattr *mx;
 454                 int len = 0;
 455
 456                 mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
 457                 if (mx == NULL)
 458                         return -ENOMEM;
 459
 460                 if (rt->rt_flags & RTF_MTU)
 461                         len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
 462
 463                 if (rt->rt_flags & RTF_WINDOW)
 464                         len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
 465
 466                 if (rt->rt_flags & RTF_IRTT)
 467                         len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
 468
 469                 cfg->fc_mx = mx;
 470                 cfg->fc_mx_len = len;
 471         }
 472
 473         return 0;
 474 }
 475
 476 /*
 477  * Handle IP routing ioctl calls.
 478  * These are used to manipulate the routing tables
 479  */
 480 int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 481 {
 482         struct fib_config cfg;
 483         struct rtentry rt;
 484         int err;
 485
 486         switch (cmd) {
 487         case SIOCADDRT:         /* Add a route */
 488         case SIOCDELRT:         /* Delete a route */
 489                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 490                         return -EPERM;
 491
 492                 if (copy_from_user(&rt, arg, sizeof(rt)))
 493                         return -EFAULT;
 494
 495                 rtnl_lock();
 496                 err = rtentry_to_fib_config(net, cmd, &rt, &cfg);
 497                 if (err == 0) {
 498                         struct fib_table *tb;
 499
 500                         if (cmd == SIOCDELRT) {
 501                                 tb = fib_get_table(net, cfg.fc_table);
 502                                 if (tb)
 503                                         err = fib_table_delete(tb, &cfg);
 504                                 else
 505                                         err = -ESRCH;
 506                         } else {
 507                                 tb = fib_new_table(net, cfg.fc_table);
 508                                 if (tb)
 509                                         err = fib_table_insert(tb, &cfg);
 510                                 else
 511                                         err = -ENOBUFS;
 512                         }
 513
 514                         /* allocated by rtentry_to_fib_config() */
 515                         kfree(cfg.fc_mx);
 516                 }
 517                 rtnl_unlock();
 518                 return err;
 519         }
 520         return -EINVAL;
 521 }
 522
 523 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
 524         [RTA_DST]               = { .type = NLA_U32 },
 525         [RTA_SRC]               = { .type = NLA_U32 },
 526         [RTA_IIF]               = { .type = NLA_U32 },
 527         [RTA_OIF]               = { .type = NLA_U32 },
 528         [RTA_GATEWAY]           = { .type = NLA_U32 },
 529         [RTA_PRIORITY]          = { .type = NLA_U32 },
 530         [RTA_PREFSRC]           = { .type = NLA_U32 },
 531         [RTA_METRICS]           = { .type = NLA_NESTED },
 532         [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
 533         [RTA_FLOW]              = { .type = NLA_U32 },
 534 };
 535
 536 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
 537                              struct nlmsghdr *nlh, struct fib_config *cfg)
 538 {
 539         struct nlattr *attr;
 540         int err, remaining;
 541         struct rtmsg *rtm;
 542
 543         err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy);
 544         if (err < 0)
 545                 goto errout;
 546
 547         memset(cfg, 0, sizeof(*cfg));
 548
 549         rtm = nlmsg_data(nlh);
 550         cfg->fc_dst_len = rtm->rtm_dst_len;
 551         cfg->fc_tos = rtm->rtm_tos;
 552         cfg->fc_table = rtm->rtm_table;
 553         cfg->fc_protocol = rtm->rtm_protocol;
 554         cfg->fc_scope = rtm->rtm_scope;
 555         cfg->fc_type = rtm->rtm_type;
 556         cfg->fc_flags = rtm->rtm_flags;
 557         cfg->fc_nlflags = nlh->nlmsg_flags;
 558
 559         cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
 560         cfg->fc_nlinfo.nlh = nlh;
 561         cfg->fc_nlinfo.nl_net = net;
 562
 563         if (cfg->fc_type > RTN_MAX) {
 564                 err = -EINVAL;
 565                 goto errout;
 566         }
 567
 568         nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
 569                 switch (nla_type(attr)) {
 570                 case RTA_DST:
 571                         cfg->fc_dst = nla_get_be32(attr);
 572                         break;
 573                 case RTA_OIF:
 574                         cfg->fc_oif = nla_get_u32(attr);
 575                         break;
 576                 case RTA_GATEWAY:
 577                         cfg->fc_gw = nla_get_be32(attr);
 578                         break;
 579                 case RTA_PRIORITY:
 580                         cfg->fc_priority = nla_get_u32(attr);
 581                         break;
 582                 case RTA_PREFSRC:
 583                         cfg->fc_prefsrc = nla_get_be32(attr);
 584                         break;
 585                 case RTA_METRICS:
 586                         cfg->fc_mx = nla_data(attr);
 587                         cfg->fc_mx_len = nla_len(attr);
 588                         break;
 589                 case RTA_MULTIPATH:
 590                         cfg->fc_mp = nla_data(attr);
 591                         cfg->fc_mp_len = nla_len(attr);
 592                         break;
 593                 case RTA_FLOW:
 594                         cfg->fc_flow = nla_get_u32(attr);
 595                         break;
 596                 case RTA_TABLE:
 597                         cfg->fc_table = nla_get_u32(attr);
 598                         break;
 599                 }
 600         }
 601
 602         return 0;
 603 errout:
 604         return err;
 605 }
 606
 607 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
 608 {
 609         struct net *net = sock_net(skb->sk);
 610         struct fib_config cfg;
 611         struct fib_table *tb;
 612         int err;
 613
 614         err = rtm_to_fib_config(net, skb, nlh, &cfg);
 615         if (err < 0)
 616                 goto errout;
 617
 618         tb = fib_get_table(net, cfg.fc_table);
 619         if (tb == NULL) {
 620                 err = -ESRCH;
 621                 goto errout;
 622         }
 623
 624         err = fib_table_delete(tb, &cfg);
 625 errout:
 626         return err;
 627 }
 628
 629 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
 630 {
 631         struct net *net = sock_net(skb->sk);
 632         struct fib_config cfg;
 633         struct fib_table *tb;
 634         int err;
 635
 636         err = rtm_to_fib_config(net, skb, nlh, &cfg);
 637         if (err < 0)
 638                 goto errout;
 639
 640         tb = fib_new_table(net, cfg.fc_table);
 641         if (tb == NULL) {
 642                 err = -ENOBUFS;
 643                 goto errout;
 644         }
 645
 646         err = fib_table_insert(tb, &cfg);
 647 errout:
 648         return err;
 649 }
 650
 651 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 652 {
 653         struct net *net = sock_net(skb->sk);
 654         unsigned int h, s_h;
 655         unsigned int e = 0, s_e;
 656         struct fib_table *tb;
 657         struct hlist_head *head;
 658         int dumped = 0;
 659
 660         if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
 661             ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
 662                 return ip_rt_dump(skb, cb);
 663
 664         s_h = cb->args[0];
 665         s_e = cb->args[1];
 666
 667         for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
 668                 e = 0;
 669                 head = &net->ipv4.fib_table_hash[h];
 670                 hlist_for_each_entry(tb, head, tb_hlist) {
 671                         if (e < s_e)
 672                                 goto next;
 673                         if (dumped)
 674                                 memset(&cb->args[2], 0, sizeof(cb->args) -
 675                                                  2 * sizeof(cb->args[0]));
 676                         if (fib_table_dump(tb, skb, cb) < 0)
 677                                 goto out;
 678                         dumped = 1;
 679 next:
 680                         e++;
 681                 }
 682         }
 683 out:
 684         cb->args[1] = e;
 685         cb->args[0] = h;
 686
 687         return skb->len;
 688 }
 689
 690 /* Prepare and feed intra-kernel routing request.
 691  * Really, it should be netlink message, but :-( netlink
 692  * can be not configured, so that we feed it directly
 693  * to fib engine. It is legal, because all events occur
 694  * only when netlink is already locked.
 695  */
 696 static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
 697 {
 698         struct net *net = dev_net(ifa->ifa_dev->dev);
 699         struct fib_table *tb;
 700         struct fib_config cfg = {
 701                 .fc_protocol = RTPROT_KERNEL,
 702                 .fc_type = type,
 703                 .fc_dst = dst,
 704                 .fc_dst_len = dst_len,
 705                 .fc_prefsrc = ifa->ifa_local,
 706                 .fc_oif = ifa->ifa_dev->dev->ifindex,
 707                 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
 708                 .fc_nlinfo = {
 709                         .nl_net = net,
 710                 },
 711         };
 712
 713         if (type == RTN_UNICAST)
 714                 tb = fib_new_table(net, RT_TABLE_MAIN);
 715         else
 716                 tb = fib_new_table(net, RT_TABLE_LOCAL);
 717
 718         if (tb == NULL)
 719                 return;
 720
 721         cfg.fc_table = tb->tb_id;
 722
 723         if (type != RTN_LOCAL)
 724                 cfg.fc_scope = RT_SCOPE_LINK;
 725         else
 726                 cfg.fc_scope = RT_SCOPE_HOST;
 727
 728         if (cmd == RTM_NEWROUTE)
 729                 fib_table_insert(tb, &cfg);
 730         else
 731                 fib_table_delete(tb, &cfg);
 732 }
 733
 734 void fib_add_ifaddr(struct in_ifaddr *ifa)
 735 {
 736         struct in_device *in_dev = ifa->ifa_dev;
 737         struct net_device *dev = in_dev->dev;
 738         struct in_ifaddr *prim = ifa;
 739         __be32 mask = ifa->ifa_mask;
 740         __be32 addr = ifa->ifa_local;
 741         __be32 prefix = ifa->ifa_address & mask;
 742
 743         if (ifa->ifa_flags & IFA_F_SECONDARY) {
 744                 prim = inet_ifa_byprefix(in_dev, prefix, mask);
 745                 if (prim == NULL) {
 746                         pr_warn("%s: bug: prim == NULL\n", __func__);
 747                         return;
 748                 }
 749         }
 750
 751         fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
 752
 753         if (!(dev->flags & IFF_UP))
 754                 return;
 755
 756         /* Add broadcast address, if it is explicitly assigned. */
 757         if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
 758                 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 759
 760         if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
 761             (prefix != addr || ifa->ifa_prefixlen < 32)) {
 762                 fib_magic(RTM_NEWROUTE,
 763                           dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
 764                           prefix, ifa->ifa_prefixlen, prim);
 765
 766                 /* Add network specific broadcasts, when it takes a sense */
 767                 if (ifa->ifa_prefixlen < 31) {
 768                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
 769                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
 770                                   32, prim);
 771                 }
 772         }
 773 }
 774
 775 /* Delete primary or secondary address.
 776  * Optionally, on secondary address promotion consider the addresses
 777  * from subnet iprim as deleted, even if they are in device list.
 778  * In this case the secondary ifa can be in device list.
 779  */
 780 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
 781 {
 782         struct in_device *in_dev = ifa->ifa_dev;
 783         struct net_device *dev = in_dev->dev;
 784         struct in_ifaddr *ifa1;
 785         struct in_ifaddr *prim = ifa, *prim1 = NULL;
 786         __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
 787         __be32 any = ifa->ifa_address & ifa->ifa_mask;
 788 #define LOCAL_OK        1
 789 #define BRD_OK          2
 790 #define BRD0_OK         4
 791 #define BRD1_OK         8
 792         unsigned int ok = 0;
 793         int subnet = 0;         /* Primary network */
 794         int gone = 1;           /* Address is missing */
 795         int same_prefsrc = 0;   /* Another primary with same IP */
 796
 797         if (ifa->ifa_flags & IFA_F_SECONDARY) {
 798                 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
 799                 if (prim == NULL) {
 800                         pr_warn("%s: bug: prim == NULL\n", __func__);
 801                         return;
 802                 }
 803                 if (iprim && iprim != prim) {
 804                         pr_warn("%s: bug: iprim != prim\n", __func__);
 805                         return;
 806                 }
 807         } else if (!ipv4_is_zeronet(any) &&
 808                    (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
 809                 fib_magic(RTM_DELROUTE,
 810                           dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
 811                           any, ifa->ifa_prefixlen, prim);
 812                 subnet = 1;
 813         }
 814
 815         /* Deletion is more complicated than add.
 816          * We should take care of not to delete too much :-)
 817          *
 818          * Scan address list to be sure that addresses are really gone.
 819          */
 820
 821         for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
 822                 if (ifa1 == ifa) {
 823                         /* promotion, keep the IP */
 824                         gone = 0;
 825                         continue;
 826                 }
 827                 /* Ignore IFAs from our subnet */
 828                 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
 829                     inet_ifa_match(ifa1->ifa_address, iprim))
 830                         continue;
 831
 832                 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
 833                 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
 834                         /* Another address from our subnet? */
 835                         if (ifa1->ifa_mask == prim->ifa_mask &&
 836                             inet_ifa_match(ifa1->ifa_address, prim))
 837                                 prim1 = prim;
 838                         else {
 839                                 /* We reached the secondaries, so
 840                                  * same_prefsrc should be determined.
 841                                  */
 842                                 if (!same_prefsrc)
 843                                         continue;
 844                                 /* Search new prim1 if ifa1 is not
 845                                  * using the current prim1
 846                                  */
 847                                 if (!prim1 ||
 848                                     ifa1->ifa_mask != prim1->ifa_mask ||
 849                                     !inet_ifa_match(ifa1->ifa_address, prim1))
 850                                         prim1 = inet_ifa_byprefix(in_dev,
 851                                                         ifa1->ifa_address,
 852                                                         ifa1->ifa_mask);
 853                                 if (!prim1)
 854                                         continue;
 855                                 if (prim1->ifa_local != prim->ifa_local)
 856                                         continue;
 857                         }
 858                 } else {
 859                         if (prim->ifa_local != ifa1->ifa_local)
 860                                 continue;
 861                         prim1 = ifa1;
 862                         if (prim != prim1)
 863                                 same_prefsrc = 1;
 864                 }
 865                 if (ifa->ifa_local == ifa1->ifa_local)
 866                         ok |= LOCAL_OK;
 867                 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
 868                         ok |= BRD_OK;
 869                 if (brd == ifa1->ifa_broadcast)
 870                         ok |= BRD1_OK;
 871                 if (any == ifa1->ifa_broadcast)
 872                         ok |= BRD0_OK;
 873                 /* primary has network specific broadcasts */
 874                 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
 875                         __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
 876                         __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
 877
 878                         if (!ipv4_is_zeronet(any1)) {
 879                                 if (ifa->ifa_broadcast == brd1 ||
 880                                     ifa->ifa_broadcast == any1)
 881                                         ok |= BRD_OK;
 882                                 if (brd == brd1 || brd == any1)
 883                                         ok |= BRD1_OK;
 884                                 if (any == brd1 || any == any1)
 885                                         ok |= BRD0_OK;
 886                         }
 887                 }
 888         }
 889
 890         if (!(ok & BRD_OK))
 891                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
 892         if (subnet && ifa->ifa_prefixlen < 31) {
 893                 if (!(ok & BRD1_OK))
 894                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
 895                 if (!(ok & BRD0_OK))
 896                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
 897         }
 898         if (!(ok & LOCAL_OK)) {
 899                 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
 900
 901                 /* Check, that this local address finally disappeared. */
 902                 if (gone &&
 903                     inet_addr_type(dev_net(dev), ifa->ifa_local) != RTN_LOCAL) {
 904                         /* And the last, but not the least thing.
 905                          * We must flush stray FIB entries.
 906                          *
 907                          * First of all, we scan fib_info list searching
 908                          * for stray nexthop entries, then ignite fib_flush.
 909                          */
 910                         if (fib_sync_down_addr(dev_net(dev), ifa->ifa_local))
 911                                 fib_flush(dev_net(dev));
 912                 }
 913         }
 914 #undef LOCAL_OK
 915 #undef BRD_OK
 916 #undef BRD0_OK
 917 #undef BRD1_OK
 918 }
 919
 920 static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
 921 {
 922
 923         struct fib_result       res;
 924         struct flowi4           fl4 = {
 925                 .flowi4_mark = frn->fl_mark,
 926                 .daddr = frn->fl_addr,
 927                 .flowi4_tos = frn->fl_tos,
 928                 .flowi4_scope = frn->fl_scope,
 929         };
 930
 931         frn->err = -ENOENT;
 932         if (tb) {
 933                 local_bh_disable();
 934
 935                 frn->tb_id = tb->tb_id;
 936                 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
 937
 938                 if (!frn->err) {
 939                         frn->prefixlen = res.prefixlen;
 940                         frn->nh_sel = res.nh_sel;
 941                         frn->type = res.type;
 942                         frn->scope = res.scope;
 943                 }
 944                 local_bh_enable();
 945         }
 946 }
 947
 948 static void nl_fib_input(struct sk_buff *skb)
 949 {
 950         struct net *net;
 951         struct fib_result_nl *frn;
 952         struct nlmsghdr *nlh;
 953         struct fib_table *tb;
 954         u32 portid;
 955
 956         net = sock_net(skb->sk);
 957         nlh = nlmsg_hdr(skb);
 958         if (skb->len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len ||
 959             nlmsg_len(nlh) < sizeof(*frn))
 960                 return;
 961
 962         skb = netlink_skb_clone(skb, GFP_KERNEL);
 963         if (skb == NULL)
 964                 return;
 965         nlh = nlmsg_hdr(skb);
 966
 967         frn = (struct fib_result_nl *) nlmsg_data(nlh);
 968         tb = fib_get_table(net, frn->tb_id_in);
 969
 970         nl_fib_lookup(frn, tb);
 971
 972         portid = NETLINK_CB(skb).portid;      /* netlink portid */
 973         NETLINK_CB(skb).portid = 0;        /* from kernel */
 974         NETLINK_CB(skb).dst_group = 0;  /* unicast */
 975         netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
 976 }
 977
 978 static int __net_init nl_fib_lookup_init(struct net *net)
 979 {
 980         struct sock *sk;
 981         struct netlink_kernel_cfg cfg = {
 982                 .input  = nl_fib_input,
 983         };
 984
 985         sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
 986         if (sk == NULL)
 987                 return -EAFNOSUPPORT;
 988         net->ipv4.fibnl = sk;
 989         return 0;
 990 }
 991
 992 static void nl_fib_lookup_exit(struct net *net)
 993 {
 994         netlink_kernel_release(net->ipv4.fibnl);
 995         net->ipv4.fibnl = NULL;
 996 }
 997
 998 static void fib_disable_ip(struct net_device *dev, int force)
 999 {
1000         if (fib_sync_down_dev(dev, force))
1001                 fib_flush(dev_net(dev));
1002         rt_cache_flush(dev_net(dev));
1003         arp_ifdown(dev);
1004 }
1005
1006 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1007 {
1008         struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1009         struct net_device *dev = ifa->ifa_dev->dev;
1010         struct net *net = dev_net(dev);
1011
1012         switch (event) {
1013         case NETDEV_UP:
1014                 fib_add_ifaddr(ifa);
1015 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1016                 fib_sync_up(dev);
1017 #endif
1018                 atomic_inc(&net->ipv4.dev_addr_genid);
1019                 rt_cache_flush(dev_net(dev));
1020                 break;
1021         case NETDEV_DOWN:
1022                 fib_del_ifaddr(ifa, NULL);
1023                 atomic_inc(&net->ipv4.dev_addr_genid);
1024                 if (ifa->ifa_dev->ifa_list == NULL) {
1025                         /* Last address was deleted from this interface.
1026                          * Disable IP.
1027                          */
1028                         fib_disable_ip(dev, 1);
1029                 } else {
1030                         rt_cache_flush(dev_net(dev));
1031                 }
1032                 break;
1033         }
1034         return NOTIFY_DONE;
1035 }
1036
1037 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1038 {
1039         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1040         struct in_device *in_dev;
1041         struct net *net = dev_net(dev);
1042
1043         if (event == NETDEV_UNREGISTER) {
1044                 fib_disable_ip(dev, 2);
1045                 rt_flush_dev(dev);
1046                 return NOTIFY_DONE;
1047         }
1048
1049         in_dev = __in_dev_get_rtnl(dev);
1050         if (!in_dev)
1051                 return NOTIFY_DONE;
1052
1053         switch (event) {
1054         case NETDEV_UP:
1055                 for_ifa(in_dev) {
1056                         fib_add_ifaddr(ifa);
1057                 } endfor_ifa(in_dev);
1058 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1059                 fib_sync_up(dev);
1060 #endif
1061                 atomic_inc(&net->ipv4.dev_addr_genid);
1062                 rt_cache_flush(net);
1063                 break;
1064         case NETDEV_DOWN:
1065                 fib_disable_ip(dev, 0);
1066                 break;
1067         case NETDEV_CHANGEMTU:
1068         case NETDEV_CHANGE:
1069                 rt_cache_flush(net);
1070                 break;
1071         }
1072         return NOTIFY_DONE;
1073 }
1074
1075 static struct notifier_block fib_inetaddr_notifier = {
1076         .notifier_call = fib_inetaddr_event,
1077 };
1078
1079 static struct notifier_block fib_netdev_notifier = {
1080         .notifier_call = fib_netdev_event,
1081 };
1082
1083 static int __net_init ip_fib_net_init(struct net *net)
1084 {
1085         int err;
1086         size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1087
1088         /* Avoid false sharing : Use at least a full cache line */
1089         size = max_t(size_t, size, L1_CACHE_BYTES);
1090
1091         net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1092         if (net->ipv4.fib_table_hash == NULL)
1093                 return -ENOMEM;
1094
1095         err = fib4_rules_init(net);
1096         if (err < 0)
1097                 goto fail;
1098         return 0;
1099
1100 fail:
1101         kfree(net->ipv4.fib_table_hash);
1102         return err;
1103 }
1104
1105 static void ip_fib_net_exit(struct net *net)
1106 {
1107         unsigned int i;
1108
1109 #ifdef CONFIG_IP_MULTIPLE_TABLES
1110         fib4_rules_exit(net);
1111 #endif
1112
1113         rtnl_lock();
1114         for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
1115                 struct fib_table *tb;
1116                 struct hlist_head *head;
1117                 struct hlist_node *tmp;
1118
1119                 head = &net->ipv4.fib_table_hash[i];
1120                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1121                         hlist_del(&tb->tb_hlist);
1122                         fib_table_flush(tb);
1123                         fib_free_table(tb);
1124                 }
1125         }
1126         rtnl_unlock();
1127         kfree(net->ipv4.fib_table_hash);
1128 }
1129
1130 static int __net_init fib_net_init(struct net *net)
1131 {
1132         int error;
1133
1134 #ifdef CONFIG_IP_ROUTE_CLASSID
1135         net->ipv4.fib_num_tclassid_users = 0;
1136 #endif
1137         error = ip_fib_net_init(net);
1138         if (error < 0)
1139                 goto out;
1140         error = nl_fib_lookup_init(net);
1141         if (error < 0)
1142                 goto out_nlfl;
1143         error = fib_proc_init(net);
1144         if (error < 0)
1145                 goto out_proc;
1146 out:
1147         return error;
1148
1149 out_proc:
1150         nl_fib_lookup_exit(net);
1151 out_nlfl:
1152         ip_fib_net_exit(net);
1153         goto out;
1154 }
1155
1156 static void __net_exit fib_net_exit(struct net *net)
1157 {
1158         fib_proc_exit(net);
1159         nl_fib_lookup_exit(net);
1160         ip_fib_net_exit(net);
1161 }
1162
1163 static struct pernet_operations fib_net_ops = {
1164         .init = fib_net_init,
1165         .exit = fib_net_exit,
1166 };
1167
1168 void __init ip_fib_init(void)
1169 {
1170         rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, NULL);
1171         rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, NULL);
1172         rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, NULL);
1173
1174         register_pernet_subsys(&fib_net_ops);
1175         register_netdevice_notifier(&fib_netdev_notifier);
1176         register_inetaddr_notifier(&fib_inetaddr_notifier);
1177
1178         fib_trie_init();
1179 }