net/netfilter/nf_nat_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * (C) 1999-2001 Paul `Rusty' Russell
   4  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   5  * (C) 2011 Patrick McHardy <kaber@trash.net>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/timer.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/gfp.h>
  15 #include <net/xfrm.h>
  16 #include <linux/siphash.h>
  17 #include <linux/rtnetlink.h>
  18
  19 #include <net/netfilter/nf_conntrack_bpf.h>
  20 #include <net/netfilter/nf_conntrack_core.h>
  21 #include <net/netfilter/nf_conntrack_helper.h>
  22 #include <net/netfilter/nf_conntrack_seqadj.h>
  23 #include <net/netfilter/nf_conntrack_zones.h>
  24 #include <net/netfilter/nf_nat.h>
  25 #include <net/netfilter/nf_nat_helper.h>
  26 #include <uapi/linux/netfilter/nf_nat.h>
  27
  28 #include "nf_internals.h"
  29
  30 #define NF_NAT_MAX_ATTEMPTS     128
  31 #define NF_NAT_HARDER_THRESH    (NF_NAT_MAX_ATTEMPTS / 4)
  32
  33 static spinlock_t nf_nat_locks[CONNTRACK_LOCKS];
  34
  35 static DEFINE_MUTEX(nf_nat_proto_mutex);
  36 static unsigned int nat_net_id __read_mostly;
  37
  38 static struct hlist_head *nf_nat_bysource __read_mostly;
  39 static unsigned int nf_nat_htable_size __read_mostly;
  40 static siphash_aligned_key_t nf_nat_hash_rnd;
  41
  42 struct nf_nat_lookup_hook_priv {
  43         struct nf_hook_entries __rcu *entries;
  44
  45         struct rcu_head rcu_head;
  46 };
  47
  48 struct nf_nat_hooks_net {
  49         struct nf_hook_ops *nat_hook_ops;
  50         unsigned int users;
  51 };
  52
  53 struct nat_net {
  54         struct nf_nat_hooks_net nat_proto_net[NFPROTO_NUMPROTO];
  55 };
  56
  57 #ifdef CONFIG_XFRM
  58 static void nf_nat_ipv4_decode_session(struct sk_buff *skb,
  59                                        const struct nf_conn *ct,
  60                                        enum ip_conntrack_dir dir,
  61                                        unsigned long statusbit,
  62                                        struct flowi *fl)
  63 {
  64         const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple;
  65         struct flowi4 *fl4 = &fl->u.ip4;
  66
  67         if (ct->status & statusbit) {
  68                 fl4->daddr = t->dst.u3.ip;
  69                 if (t->dst.protonum == IPPROTO_TCP ||
  70                     t->dst.protonum == IPPROTO_UDP ||
  71                     t->dst.protonum == IPPROTO_UDPLITE ||
  72                     t->dst.protonum == IPPROTO_DCCP ||
  73                     t->dst.protonum == IPPROTO_SCTP)
  74                         fl4->fl4_dport = t->dst.u.all;
  75         }
  76
  77         statusbit ^= IPS_NAT_MASK;
  78
  79         if (ct->status & statusbit) {
  80                 fl4->saddr = t->src.u3.ip;
  81                 if (t->dst.protonum == IPPROTO_TCP ||
  82                     t->dst.protonum == IPPROTO_UDP ||
  83                     t->dst.protonum == IPPROTO_UDPLITE ||
  84                     t->dst.protonum == IPPROTO_DCCP ||
  85                     t->dst.protonum == IPPROTO_SCTP)
  86                         fl4->fl4_sport = t->src.u.all;
  87         }
  88 }
  89
  90 static void nf_nat_ipv6_decode_session(struct sk_buff *skb,
  91                                        const struct nf_conn *ct,
  92                                        enum ip_conntrack_dir dir,
  93                                        unsigned long statusbit,
  94                                        struct flowi *fl)
  95 {
  96 #if IS_ENABLED(CONFIG_IPV6)
  97         const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple;
  98         struct flowi6 *fl6 = &fl->u.ip6;
  99
 100         if (ct->status & statusbit) {
 101                 fl6->daddr = t->dst.u3.in6;
 102                 if (t->dst.protonum == IPPROTO_TCP ||
 103                     t->dst.protonum == IPPROTO_UDP ||
 104                     t->dst.protonum == IPPROTO_UDPLITE ||
 105                     t->dst.protonum == IPPROTO_DCCP ||
 106                     t->dst.protonum == IPPROTO_SCTP)
 107                         fl6->fl6_dport = t->dst.u.all;
 108         }
 109
 110         statusbit ^= IPS_NAT_MASK;
 111
 112         if (ct->status & statusbit) {
 113                 fl6->saddr = t->src.u3.in6;
 114                 if (t->dst.protonum == IPPROTO_TCP ||
 115                     t->dst.protonum == IPPROTO_UDP ||
 116                     t->dst.protonum == IPPROTO_UDPLITE ||
 117                     t->dst.protonum == IPPROTO_DCCP ||
 118                     t->dst.protonum == IPPROTO_SCTP)
 119                         fl6->fl6_sport = t->src.u.all;
 120         }
 121 #endif
 122 }
 123
 124 static void __nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl)
 125 {
 126         const struct nf_conn *ct;
 127         enum ip_conntrack_info ctinfo;
 128         enum ip_conntrack_dir dir;
 129         unsigned  long statusbit;
 130         u8 family;
 131
 132         ct = nf_ct_get(skb, &ctinfo);
 133         if (ct == NULL)
 134                 return;
 135
 136         family = nf_ct_l3num(ct);
 137         dir = CTINFO2DIR(ctinfo);
 138         if (dir == IP_CT_DIR_ORIGINAL)
 139                 statusbit = IPS_DST_NAT;
 140         else
 141                 statusbit = IPS_SRC_NAT;
 142
 143         switch (family) {
 144         case NFPROTO_IPV4:
 145                 nf_nat_ipv4_decode_session(skb, ct, dir, statusbit, fl);
 146                 return;
 147         case NFPROTO_IPV6:
 148                 nf_nat_ipv6_decode_session(skb, ct, dir, statusbit, fl);
 149                 return;
 150         }
 151 }
 152 #endif /* CONFIG_XFRM */
 153
 154 /* We keep an extra hash for each conntrack, for fast searching. */
 155 static unsigned int
 156 hash_by_src(const struct net *net,
 157             const struct nf_conntrack_zone *zone,
 158             const struct nf_conntrack_tuple *tuple)
 159 {
 160         unsigned int hash;
 161         struct {
 162                 struct nf_conntrack_man src;
 163                 u32 net_mix;
 164                 u32 protonum;
 165                 u32 zone;
 166         } __aligned(SIPHASH_ALIGNMENT) combined;
 167
 168         get_random_once(&nf_nat_hash_rnd, sizeof(nf_nat_hash_rnd));
 169
 170         memset(&combined, 0, sizeof(combined));
 171
 172         /* Original src, to ensure we map it consistently if poss. */
 173         combined.src = tuple->src;
 174         combined.net_mix = net_hash_mix(net);
 175         combined.protonum = tuple->dst.protonum;
 176
 177         /* Zone ID can be used provided its valid for both directions */
 178         if (zone->dir == NF_CT_DEFAULT_ZONE_DIR)
 179                 combined.zone = zone->id;
 180
 181         hash = siphash(&combined, sizeof(combined), &nf_nat_hash_rnd);
 182
 183         return reciprocal_scale(hash, nf_nat_htable_size);
 184 }
 185
 186 /* Is this tuple already taken? (not by us) */
 187 static int
 188 nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
 189                   const struct nf_conn *ignored_conntrack)
 190 {
 191         /* Conntrack tracking doesn't keep track of outgoing tuples; only
 192          * incoming ones.  NAT means they don't have a fixed mapping,
 193          * so we invert the tuple and look for the incoming reply.
 194          *
 195          * We could keep a separate hash if this proves too slow.
 196          */
 197         struct nf_conntrack_tuple reply;
 198
 199         nf_ct_invert_tuple(&reply, tuple);
 200         return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
 201 }
 202
 203 static bool nf_nat_may_kill(struct nf_conn *ct, unsigned long flags)
 204 {
 205         static const unsigned long flags_refuse = IPS_FIXED_TIMEOUT |
 206                                                   IPS_DYING;
 207         static const unsigned long flags_needed = IPS_SRC_NAT;
 208         enum tcp_conntrack old_state;
 209
 210         old_state = READ_ONCE(ct->proto.tcp.state);
 211         if (old_state < TCP_CONNTRACK_TIME_WAIT)
 212                 return false;
 213
 214         if (flags & flags_refuse)
 215                 return false;
 216
 217         return (flags & flags_needed) == flags_needed;
 218 }
 219
 220 /* reverse direction will send packets to new source, so
 221  * make sure such packets are invalid.
 222  */
 223 static bool nf_seq_has_advanced(const struct nf_conn *old, const struct nf_conn *new)
 224 {
 225         return (__s32)(new->proto.tcp.seen[0].td_end -
 226                        old->proto.tcp.seen[0].td_end) > 0;
 227 }
 228
 229 static int
 230 nf_nat_used_tuple_harder(const struct nf_conntrack_tuple *tuple,
 231                          const struct nf_conn *ignored_conntrack,
 232                          unsigned int attempts_left)
 233 {
 234         static const unsigned long flags_offload = IPS_OFFLOAD | IPS_HW_OFFLOAD;
 235         struct nf_conntrack_tuple_hash *thash;
 236         const struct nf_conntrack_zone *zone;
 237         struct nf_conntrack_tuple reply;
 238         unsigned long flags;
 239         struct nf_conn *ct;
 240         bool taken = true;
 241         struct net *net;
 242
 243         nf_ct_invert_tuple(&reply, tuple);
 244
 245         if (attempts_left > NF_NAT_HARDER_THRESH ||
 246             tuple->dst.protonum != IPPROTO_TCP ||
 247             ignored_conntrack->proto.tcp.state != TCP_CONNTRACK_SYN_SENT)
 248                 return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
 249
 250         /* :ast few attempts to find a free tcp port. Destructive
 251          * action: evict colliding if its in timewait state and the
 252          * tcp sequence number has advanced past the one used by the
 253          * old entry.
 254          */
 255         net = nf_ct_net(ignored_conntrack);
 256         zone = nf_ct_zone(ignored_conntrack);
 257
 258         thash = nf_conntrack_find_get(net, zone, &reply);
 259         if (!thash)
 260                 return false;
 261
 262         ct = nf_ct_tuplehash_to_ctrack(thash);
 263
 264         if (thash->tuple.dst.dir == IP_CT_DIR_ORIGINAL)
 265                 goto out;
 266
 267         if (WARN_ON_ONCE(ct == ignored_conntrack))
 268                 goto out;
 269
 270         flags = READ_ONCE(ct->status);
 271         if (!nf_nat_may_kill(ct, flags))
 272                 goto out;
 273
 274         if (!nf_seq_has_advanced(ct, ignored_conntrack))
 275                 goto out;
 276
 277         /* Even if we can evict do not reuse if entry is offloaded. */
 278         if (nf_ct_kill(ct))
 279                 taken = flags & flags_offload;
 280 out:
 281         nf_ct_put(ct);
 282         return taken;
 283 }
 284
 285 static bool nf_nat_inet_in_range(const struct nf_conntrack_tuple *t,
 286                                  const struct nf_nat_range2 *range)
 287 {
 288         if (t->src.l3num == NFPROTO_IPV4)
 289                 return ntohl(t->src.u3.ip) >= ntohl(range->min_addr.ip) &&
 290                        ntohl(t->src.u3.ip) <= ntohl(range->max_addr.ip);
 291
 292         return ipv6_addr_cmp(&t->src.u3.in6, &range->min_addr.in6) >= 0 &&
 293                ipv6_addr_cmp(&t->src.u3.in6, &range->max_addr.in6) <= 0;
 294 }
 295
 296 /* Is the manipable part of the tuple between min and max incl? */
 297 static bool l4proto_in_range(const struct nf_conntrack_tuple *tuple,
 298                              enum nf_nat_manip_type maniptype,
 299                              const union nf_conntrack_man_proto *min,
 300                              const union nf_conntrack_man_proto *max)
 301 {
 302         __be16 port;
 303
 304         switch (tuple->dst.protonum) {
 305         case IPPROTO_ICMP:
 306         case IPPROTO_ICMPV6:
 307                 return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) &&
 308                        ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
 309         case IPPROTO_GRE: /* all fall though */
 310         case IPPROTO_TCP:
 311         case IPPROTO_UDP:
 312         case IPPROTO_UDPLITE:
 313         case IPPROTO_DCCP:
 314         case IPPROTO_SCTP:
 315                 if (maniptype == NF_NAT_MANIP_SRC)
 316                         port = tuple->src.u.all;
 317                 else
 318                         port = tuple->dst.u.all;
 319
 320                 return ntohs(port) >= ntohs(min->all) &&
 321                        ntohs(port) <= ntohs(max->all);
 322         default:
 323                 return true;
 324         }
 325 }
 326
 327 /* If we source map this tuple so reply looks like reply_tuple, will
 328  * that meet the constraints of range.
 329  */
 330 static int nf_in_range(const struct nf_conntrack_tuple *tuple,
 331                     const struct nf_nat_range2 *range)
 332 {
 333         /* If we are supposed to map IPs, then we must be in the
 334          * range specified, otherwise let this drag us onto a new src IP.
 335          */
 336         if (range->flags & NF_NAT_RANGE_MAP_IPS &&
 337             !nf_nat_inet_in_range(tuple, range))
 338                 return 0;
 339
 340         if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED))
 341                 return 1;
 342
 343         return l4proto_in_range(tuple, NF_NAT_MANIP_SRC,
 344                                 &range->min_proto, &range->max_proto);
 345 }
 346
 347 static inline int
 348 same_src(const struct nf_conn *ct,
 349          const struct nf_conntrack_tuple *tuple)
 350 {
 351         const struct nf_conntrack_tuple *t;
 352
 353         t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
 354         return (t->dst.protonum == tuple->dst.protonum &&
 355                 nf_inet_addr_cmp(&t->src.u3, &tuple->src.u3) &&
 356                 t->src.u.all == tuple->src.u.all);
 357 }
 358
 359 /* Only called for SRC manip */
 360 static int
 361 find_appropriate_src(struct net *net,
 362                      const struct nf_conntrack_zone *zone,
 363                      const struct nf_conntrack_tuple *tuple,
 364                      struct nf_conntrack_tuple *result,
 365                      const struct nf_nat_range2 *range)
 366 {
 367         unsigned int h = hash_by_src(net, zone, tuple);
 368         const struct nf_conn *ct;
 369
 370         hlist_for_each_entry_rcu(ct, &nf_nat_bysource[h], nat_bysource) {
 371                 if (same_src(ct, tuple) &&
 372                     net_eq(net, nf_ct_net(ct)) &&
 373                     nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) {
 374                         /* Copy source part from reply tuple. */
 375                         nf_ct_invert_tuple(result,
 376                                        &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 377                         result->dst = tuple->dst;
 378
 379                         if (nf_in_range(result, range))
 380                                 return 1;
 381                 }
 382         }
 383         return 0;
 384 }
 385
 386 /* For [FUTURE] fragmentation handling, we want the least-used
 387  * src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
 388  * if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
 389  * 1-65535, we don't do pro-rata allocation based on ports; we choose
 390  * the ip with the lowest src-ip/dst-ip/proto usage.
 391  */
 392 static void
 393 find_best_ips_proto(const struct nf_conntrack_zone *zone,
 394                     struct nf_conntrack_tuple *tuple,
 395                     const struct nf_nat_range2 *range,
 396                     const struct nf_conn *ct,
 397                     enum nf_nat_manip_type maniptype)
 398 {
 399         union nf_inet_addr *var_ipp;
 400         unsigned int i, max;
 401         /* Host order */
 402         u32 minip, maxip, j, dist;
 403         bool full_range;
 404
 405         /* No IP mapping?  Do nothing. */
 406         if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
 407                 return;
 408
 409         if (maniptype == NF_NAT_MANIP_SRC)
 410                 var_ipp = &tuple->src.u3;
 411         else
 412                 var_ipp = &tuple->dst.u3;
 413
 414         /* Fast path: only one choice. */
 415         if (nf_inet_addr_cmp(&range->min_addr, &range->max_addr)) {
 416                 *var_ipp = range->min_addr;
 417                 return;
 418         }
 419
 420         if (nf_ct_l3num(ct) == NFPROTO_IPV4)
 421                 max = sizeof(var_ipp->ip) / sizeof(u32) - 1;
 422         else
 423                 max = sizeof(var_ipp->ip6) / sizeof(u32) - 1;
 424
 425         /* Hashing source and destination IPs gives a fairly even
 426          * spread in practice (if there are a small number of IPs
 427          * involved, there usually aren't that many connections
 428          * anyway).  The consistency means that servers see the same
 429          * client coming from the same IP (some Internet Banking sites
 430          * like this), even across reboots.
 431          */
 432         j = jhash2((u32 *)&tuple->src.u3, sizeof(tuple->src.u3) / sizeof(u32),
 433                    range->flags & NF_NAT_RANGE_PERSISTENT ?
 434                         0 : (__force u32)tuple->dst.u3.all[max] ^ zone->id);
 435
 436         full_range = false;
 437         for (i = 0; i <= max; i++) {
 438                 /* If first bytes of the address are at the maximum, use the
 439                  * distance. Otherwise use the full range.
 440                  */
 441                 if (!full_range) {
 442                         minip = ntohl((__force __be32)range->min_addr.all[i]);
 443                         maxip = ntohl((__force __be32)range->max_addr.all[i]);
 444                         dist  = maxip - minip + 1;
 445                 } else {
 446                         minip = 0;
 447                         dist  = ~0;
 448                 }
 449
 450                 var_ipp->all[i] = (__force __u32)
 451                         htonl(minip + reciprocal_scale(j, dist));
 452                 if (var_ipp->all[i] != range->max_addr.all[i])
 453                         full_range = true;
 454
 455                 if (!(range->flags & NF_NAT_RANGE_PERSISTENT))
 456                         j ^= (__force u32)tuple->dst.u3.all[i];
 457         }
 458 }
 459
 460 /* Alter the per-proto part of the tuple (depending on maniptype), to
 461  * give a unique tuple in the given range if possible.
 462  *
 463  * Per-protocol part of tuple is initialized to the incoming packet.
 464  */
 465 static void nf_nat_l4proto_unique_tuple(struct nf_conntrack_tuple *tuple,
 466                                         const struct nf_nat_range2 *range,
 467                                         enum nf_nat_manip_type maniptype,
 468                                         const struct nf_conn *ct)
 469 {
 470         unsigned int range_size, min, max, i, attempts;
 471         __be16 *keyptr;
 472         u16 off;
 473
 474         switch (tuple->dst.protonum) {
 475         case IPPROTO_ICMP:
 476         case IPPROTO_ICMPV6:
 477                 /* id is same for either direction... */
 478                 keyptr = &tuple->src.u.icmp.id;
 479                 if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
 480                         min = 0;
 481                         range_size = 65536;
 482                 } else {
 483                         min = ntohs(range->min_proto.icmp.id);
 484                         range_size = ntohs(range->max_proto.icmp.id) -
 485                                      ntohs(range->min_proto.icmp.id) + 1;
 486                 }
 487                 goto find_free_id;
 488 #if IS_ENABLED(CONFIG_NF_CT_PROTO_GRE)
 489         case IPPROTO_GRE:
 490                 /* If there is no master conntrack we are not PPTP,
 491                    do not change tuples */
 492                 if (!ct->master)
 493                         return;
 494
 495                 if (maniptype == NF_NAT_MANIP_SRC)
 496                         keyptr = &tuple->src.u.gre.key;
 497                 else
 498                         keyptr = &tuple->dst.u.gre.key;
 499
 500                 if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
 501                         min = 1;
 502                         range_size = 65535;
 503                 } else {
 504                         min = ntohs(range->min_proto.gre.key);
 505                         range_size = ntohs(range->max_proto.gre.key) - min + 1;
 506                 }
 507                 goto find_free_id;
 508 #endif
 509         case IPPROTO_UDP:
 510         case IPPROTO_UDPLITE:
 511         case IPPROTO_TCP:
 512         case IPPROTO_SCTP:
 513         case IPPROTO_DCCP:
 514                 if (maniptype == NF_NAT_MANIP_SRC)
 515                         keyptr = &tuple->src.u.all;
 516                 else
 517                         keyptr = &tuple->dst.u.all;
 518
 519                 break;
 520         default:
 521                 return;
 522         }
 523
 524         /* If no range specified... */
 525         if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
 526                 /* If it's dst rewrite, can't change port */
 527                 if (maniptype == NF_NAT_MANIP_DST)
 528                         return;
 529
 530                 if (ntohs(*keyptr) < 1024) {
 531                         /* Loose convention: >> 512 is credential passing */
 532                         if (ntohs(*keyptr) < 512) {
 533                                 min = 1;
 534                                 range_size = 511 - min + 1;
 535                         } else {
 536                                 min = 600;
 537                                 range_size = 1023 - min + 1;
 538                         }
 539                 } else {
 540                         min = 1024;
 541                         range_size = 65535 - 1024 + 1;
 542                 }
 543         } else {
 544                 min = ntohs(range->min_proto.all);
 545                 max = ntohs(range->max_proto.all);
 546                 if (unlikely(max < min))
 547                         swap(max, min);
 548                 range_size = max - min + 1;
 549         }
 550
 551 find_free_id:
 552         if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
 553                 off = (ntohs(*keyptr) - ntohs(range->base_proto.all));
 554         else
 555                 off = get_random_u16();
 556
 557         attempts = range_size;
 558         if (attempts > NF_NAT_MAX_ATTEMPTS)
 559                 attempts = NF_NAT_MAX_ATTEMPTS;
 560
 561         /* We are in softirq; doing a search of the entire range risks
 562          * soft lockup when all tuples are already used.
 563          *
 564          * If we can't find any free port from first offset, pick a new
 565          * one and try again, with ever smaller search window.
 566          */
 567 another_round:
 568         for (i = 0; i < attempts; i++, off++) {
 569                 *keyptr = htons(min + off % range_size);
 570                 if (!nf_nat_used_tuple_harder(tuple, ct, attempts - i))
 571                         return;
 572         }
 573
 574         if (attempts >= range_size || attempts < 16)
 575                 return;
 576         attempts /= 2;
 577         off = get_random_u16();
 578         goto another_round;
 579 }
 580
 581 /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
 582  * we change the source to map into the range. For NF_INET_PRE_ROUTING
 583  * and NF_INET_LOCAL_OUT, we change the destination to map into the
 584  * range. It might not be possible to get a unique tuple, but we try.
 585  * At worst (or if we race), we will end up with a final duplicate in
 586  * __nf_conntrack_confirm and drop the packet. */
 587 static void
 588 get_unique_tuple(struct nf_conntrack_tuple *tuple,
 589                  const struct nf_conntrack_tuple *orig_tuple,
 590                  const struct nf_nat_range2 *range,
 591                  struct nf_conn *ct,
 592                  enum nf_nat_manip_type maniptype)
 593 {
 594         const struct nf_conntrack_zone *zone;
 595         struct net *net = nf_ct_net(ct);
 596
 597         zone = nf_ct_zone(ct);
 598
 599         /* 1) If this srcip/proto/src-proto-part is currently mapped,
 600          * and that same mapping gives a unique tuple within the given
 601          * range, use that.
 602          *
 603          * This is only required for source (ie. NAT/masq) mappings.
 604          * So far, we don't do local source mappings, so multiple
 605          * manips not an issue.
 606          */
 607         if (maniptype == NF_NAT_MANIP_SRC &&
 608             !(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
 609                 /* try the original tuple first */
 610                 if (nf_in_range(orig_tuple, range)) {
 611                         if (!nf_nat_used_tuple(orig_tuple, ct)) {
 612                                 *tuple = *orig_tuple;
 613                                 return;
 614                         }
 615                 } else if (find_appropriate_src(net, zone,
 616                                                 orig_tuple, tuple, range)) {
 617                         pr_debug("get_unique_tuple: Found current src map\n");
 618                         if (!nf_nat_used_tuple(tuple, ct))
 619                                 return;
 620                 }
 621         }
 622
 623         /* 2) Select the least-used IP/proto combination in the given range */
 624         *tuple = *orig_tuple;
 625         find_best_ips_proto(zone, tuple, range, ct, maniptype);
 626
 627         /* 3) The per-protocol part of the manip is made to map into
 628          * the range to make a unique tuple.
 629          */
 630
 631         /* Only bother mapping if it's not already in range and unique */
 632         if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
 633                 if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
 634                         if (!(range->flags & NF_NAT_RANGE_PROTO_OFFSET) &&
 635                             l4proto_in_range(tuple, maniptype,
 636                                              &range->min_proto,
 637                                              &range->max_proto) &&
 638                             (range->min_proto.all == range->max_proto.all ||
 639                              !nf_nat_used_tuple(tuple, ct)))
 640                                 return;
 641                 } else if (!nf_nat_used_tuple(tuple, ct)) {
 642                         return;
 643                 }
 644         }
 645
 646         /* Last chance: get protocol to try to obtain unique tuple. */
 647         nf_nat_l4proto_unique_tuple(tuple, range, maniptype, ct);
 648 }
 649
 650 struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct)
 651 {
 652         struct nf_conn_nat *nat = nfct_nat(ct);
 653         if (nat)
 654                 return nat;
 655
 656         if (!nf_ct_is_confirmed(ct))
 657                 nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
 658
 659         return nat;
 660 }
 661 EXPORT_SYMBOL_GPL(nf_ct_nat_ext_add);
 662
 663 unsigned int
 664 nf_nat_setup_info(struct nf_conn *ct,
 665                   const struct nf_nat_range2 *range,
 666                   enum nf_nat_manip_type maniptype)
 667 {
 668         struct net *net = nf_ct_net(ct);
 669         struct nf_conntrack_tuple curr_tuple, new_tuple;
 670
 671         /* Can't setup nat info for confirmed ct. */
 672         if (nf_ct_is_confirmed(ct))
 673                 return NF_ACCEPT;
 674
 675         WARN_ON(maniptype != NF_NAT_MANIP_SRC &&
 676                 maniptype != NF_NAT_MANIP_DST);
 677
 678         if (WARN_ON(nf_nat_initialized(ct, maniptype)))
 679                 return NF_DROP;
 680
 681         /* What we've got will look like inverse of reply. Normally
 682          * this is what is in the conntrack, except for prior
 683          * manipulations (future optimization: if num_manips == 0,
 684          * orig_tp = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
 685          */
 686         nf_ct_invert_tuple(&curr_tuple,
 687                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 688
 689         get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
 690
 691         if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
 692                 struct nf_conntrack_tuple reply;
 693
 694                 /* Alter conntrack table so will recognize replies. */
 695                 nf_ct_invert_tuple(&reply, &new_tuple);
 696                 nf_conntrack_alter_reply(ct, &reply);
 697
 698                 /* Non-atomic: we own this at the moment. */
 699                 if (maniptype == NF_NAT_MANIP_SRC)
 700                         ct->status |= IPS_SRC_NAT;
 701                 else
 702                         ct->status |= IPS_DST_NAT;
 703
 704                 if (nfct_help(ct) && !nfct_seqadj(ct))
 705                         if (!nfct_seqadj_ext_add(ct))
 706                                 return NF_DROP;
 707         }
 708
 709         if (maniptype == NF_NAT_MANIP_SRC) {
 710                 unsigned int srchash;
 711                 spinlock_t *lock;
 712
 713                 srchash = hash_by_src(net, nf_ct_zone(ct),
 714                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 715                 lock = &nf_nat_locks[srchash % CONNTRACK_LOCKS];
 716                 spin_lock_bh(lock);
 717                 hlist_add_head_rcu(&ct->nat_bysource,
 718                                    &nf_nat_bysource[srchash]);
 719                 spin_unlock_bh(lock);
 720         }
 721
 722         /* It's done. */
 723         if (maniptype == NF_NAT_MANIP_DST)
 724                 ct->status |= IPS_DST_NAT_DONE;
 725         else
 726                 ct->status |= IPS_SRC_NAT_DONE;
 727
 728         return NF_ACCEPT;
 729 }
 730 EXPORT_SYMBOL(nf_nat_setup_info);
 731
 732 static unsigned int
 733 __nf_nat_alloc_null_binding(struct nf_conn *ct, enum nf_nat_manip_type manip)
 734 {
 735         /* Force range to this IP; let proto decide mapping for
 736          * per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
 737          * Use reply in case it's already been mangled (eg local packet).
 738          */
 739         union nf_inet_addr ip =
 740                 (manip == NF_NAT_MANIP_SRC ?
 741                 ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3 :
 742                 ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3);
 743         struct nf_nat_range2 range = {
 744                 .flags          = NF_NAT_RANGE_MAP_IPS,
 745                 .min_addr       = ip,
 746                 .max_addr       = ip,
 747         };
 748         return nf_nat_setup_info(ct, &range, manip);
 749 }
 750
 751 unsigned int
 752 nf_nat_alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
 753 {
 754         return __nf_nat_alloc_null_binding(ct, HOOK2MANIP(hooknum));
 755 }
 756 EXPORT_SYMBOL_GPL(nf_nat_alloc_null_binding);
 757
 758 /* Do packet manipulations according to nf_nat_setup_info. */
 759 unsigned int nf_nat_packet(struct nf_conn *ct,
 760                            enum ip_conntrack_info ctinfo,
 761                            unsigned int hooknum,
 762                            struct sk_buff *skb)
 763 {
 764         enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
 765         enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 766         unsigned int verdict = NF_ACCEPT;
 767         unsigned long statusbit;
 768
 769         if (mtype == NF_NAT_MANIP_SRC)
 770                 statusbit = IPS_SRC_NAT;
 771         else
 772                 statusbit = IPS_DST_NAT;
 773
 774         /* Invert if this is reply dir. */
 775         if (dir == IP_CT_DIR_REPLY)
 776                 statusbit ^= IPS_NAT_MASK;
 777
 778         /* Non-atomic: these bits don't change. */
 779         if (ct->status & statusbit)
 780                 verdict = nf_nat_manip_pkt(skb, ct, mtype, dir);
 781
 782         return verdict;
 783 }
 784 EXPORT_SYMBOL_GPL(nf_nat_packet);
 785
 786 static bool in_vrf_postrouting(const struct nf_hook_state *state)
 787 {
 788 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
 789         if (state->hook == NF_INET_POST_ROUTING &&
 790             netif_is_l3_master(state->out))
 791                 return true;
 792 #endif
 793         return false;
 794 }
 795
 796 unsigned int
 797 nf_nat_inet_fn(void *priv, struct sk_buff *skb,
 798                const struct nf_hook_state *state)
 799 {
 800         struct nf_conn *ct;
 801         enum ip_conntrack_info ctinfo;
 802         struct nf_conn_nat *nat;
 803         /* maniptype == SRC for postrouting. */
 804         enum nf_nat_manip_type maniptype = HOOK2MANIP(state->hook);
 805
 806         ct = nf_ct_get(skb, &ctinfo);
 807         /* Can't track?  It's not due to stress, or conntrack would
 808          * have dropped it.  Hence it's the user's responsibilty to
 809          * packet filter it out, or implement conntrack/NAT for that
 810          * protocol. 8) --RR
 811          */
 812         if (!ct || in_vrf_postrouting(state))
 813                 return NF_ACCEPT;
 814
 815         nat = nfct_nat(ct);
 816
 817         switch (ctinfo) {
 818         case IP_CT_RELATED:
 819         case IP_CT_RELATED_REPLY:
 820                 /* Only ICMPs can be IP_CT_IS_REPLY.  Fallthrough */
 821         case IP_CT_NEW:
 822                 /* Seen it before?  This can happen for loopback, retrans,
 823                  * or local packets.
 824                  */
 825                 if (!nf_nat_initialized(ct, maniptype)) {
 826                         struct nf_nat_lookup_hook_priv *lpriv = priv;
 827                         struct nf_hook_entries *e = rcu_dereference(lpriv->entries);
 828                         unsigned int ret;
 829                         int i;
 830
 831                         if (!e)
 832                                 goto null_bind;
 833
 834                         for (i = 0; i < e->num_hook_entries; i++) {
 835                                 ret = e->hooks[i].hook(e->hooks[i].priv, skb,
 836                                                        state);
 837                                 if (ret != NF_ACCEPT)
 838                                         return ret;
 839                                 if (nf_nat_initialized(ct, maniptype))
 840                                         goto do_nat;
 841                         }
 842 null_bind:
 843                         ret = nf_nat_alloc_null_binding(ct, state->hook);
 844                         if (ret != NF_ACCEPT)
 845                                 return ret;
 846                 } else {
 847                         pr_debug("Already setup manip %s for ct %p (status bits 0x%lx)\n",
 848                                  maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
 849                                  ct, ct->status);
 850                         if (nf_nat_oif_changed(state->hook, ctinfo, nat,
 851                                                state->out))
 852                                 goto oif_changed;
 853                 }
 854                 break;
 855         default:
 856                 /* ESTABLISHED */
 857                 WARN_ON(ctinfo != IP_CT_ESTABLISHED &&
 858                         ctinfo != IP_CT_ESTABLISHED_REPLY);
 859                 if (nf_nat_oif_changed(state->hook, ctinfo, nat, state->out))
 860                         goto oif_changed;
 861         }
 862 do_nat:
 863         return nf_nat_packet(ct, ctinfo, state->hook, skb);
 864
 865 oif_changed:
 866         nf_ct_kill_acct(ct, ctinfo, skb);
 867         return NF_DROP;
 868 }
 869 EXPORT_SYMBOL_GPL(nf_nat_inet_fn);
 870
 871 struct nf_nat_proto_clean {
 872         u8      l3proto;
 873         u8      l4proto;
 874 };
 875
 876 /* kill conntracks with affected NAT section */
 877 static int nf_nat_proto_remove(struct nf_conn *i, void *data)
 878 {
 879         const struct nf_nat_proto_clean *clean = data;
 880
 881         if ((clean->l3proto && nf_ct_l3num(i) != clean->l3proto) ||
 882             (clean->l4proto && nf_ct_protonum(i) != clean->l4proto))
 883                 return 0;
 884
 885         return i->status & IPS_NAT_MASK ? 1 : 0;
 886 }
 887
 888 static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
 889 {
 890         unsigned int h;
 891
 892         h = hash_by_src(nf_ct_net(ct), nf_ct_zone(ct), &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 893         spin_lock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
 894         hlist_del_rcu(&ct->nat_bysource);
 895         spin_unlock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
 896 }
 897
 898 static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
 899 {
 900         if (nf_nat_proto_remove(ct, data))
 901                 return 1;
 902
 903         /* This module is being removed and conntrack has nat null binding.
 904          * Remove it from bysource hash, as the table will be freed soon.
 905          *
 906          * Else, when the conntrack is destoyed, nf_nat_cleanup_conntrack()
 907          * will delete entry from already-freed table.
 908          */
 909         if (test_and_clear_bit(IPS_SRC_NAT_DONE_BIT, &ct->status))
 910                 nf_nat_cleanup_conntrack(ct);
 911
 912         /* don't delete conntrack.  Although that would make things a lot
 913          * simpler, we'd end up flushing all conntracks on nat rmmod.
 914          */
 915         return 0;
 916 }
 917
 918 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 919
 920 #include <linux/netfilter/nfnetlink.h>
 921 #include <linux/netfilter/nfnetlink_conntrack.h>
 922
 923 static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
 924         [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
 925         [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
 926 };
 927
 928 static int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
 929                                           struct nf_nat_range2 *range)
 930 {
 931         if (tb[CTA_PROTONAT_PORT_MIN]) {
 932                 range->min_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]);
 933                 range->max_proto.all = range->min_proto.all;
 934                 range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
 935         }
 936         if (tb[CTA_PROTONAT_PORT_MAX]) {
 937                 range->max_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]);
 938                 range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
 939         }
 940         return 0;
 941 }
 942
 943 static int nfnetlink_parse_nat_proto(struct nlattr *attr,
 944                                      const struct nf_conn *ct,
 945                                      struct nf_nat_range2 *range)
 946 {
 947         struct nlattr *tb[CTA_PROTONAT_MAX+1];
 948         int err;
 949
 950         err = nla_parse_nested_deprecated(tb, CTA_PROTONAT_MAX, attr,
 951                                           protonat_nla_policy, NULL);
 952         if (err < 0)
 953                 return err;
 954
 955         return nf_nat_l4proto_nlattr_to_range(tb, range);
 956 }
 957
 958 static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
 959         [CTA_NAT_V4_MINIP]      = { .type = NLA_U32 },
 960         [CTA_NAT_V4_MAXIP]      = { .type = NLA_U32 },
 961         [CTA_NAT_V6_MINIP]      = { .len = sizeof(struct in6_addr) },
 962         [CTA_NAT_V6_MAXIP]      = { .len = sizeof(struct in6_addr) },
 963         [CTA_NAT_PROTO]         = { .type = NLA_NESTED },
 964 };
 965
 966 static int nf_nat_ipv4_nlattr_to_range(struct nlattr *tb[],
 967                                        struct nf_nat_range2 *range)
 968 {
 969         if (tb[CTA_NAT_V4_MINIP]) {
 970                 range->min_addr.ip = nla_get_be32(tb[CTA_NAT_V4_MINIP]);
 971                 range->flags |= NF_NAT_RANGE_MAP_IPS;
 972         }
 973
 974         if (tb[CTA_NAT_V4_MAXIP])
 975                 range->max_addr.ip = nla_get_be32(tb[CTA_NAT_V4_MAXIP]);
 976         else
 977                 range->max_addr.ip = range->min_addr.ip;
 978
 979         return 0;
 980 }
 981
 982 static int nf_nat_ipv6_nlattr_to_range(struct nlattr *tb[],
 983                                        struct nf_nat_range2 *range)
 984 {
 985         if (tb[CTA_NAT_V6_MINIP]) {
 986                 nla_memcpy(&range->min_addr.ip6, tb[CTA_NAT_V6_MINIP],
 987                            sizeof(struct in6_addr));
 988                 range->flags |= NF_NAT_RANGE_MAP_IPS;
 989         }
 990
 991         if (tb[CTA_NAT_V6_MAXIP])
 992                 nla_memcpy(&range->max_addr.ip6, tb[CTA_NAT_V6_MAXIP],
 993                            sizeof(struct in6_addr));
 994         else
 995                 range->max_addr = range->min_addr;
 996
 997         return 0;
 998 }
 999
1000 static int
1001 nfnetlink_parse_nat(const struct nlattr *nat,
1002                     const struct nf_conn *ct, struct nf_nat_range2 *range)
1003 {
1004         struct nlattr *tb[CTA_NAT_MAX+1];
1005         int err;
1006
1007         memset(range, 0, sizeof(*range));
1008
1009         err = nla_parse_nested_deprecated(tb, CTA_NAT_MAX, nat,
1010                                           nat_nla_policy, NULL);
1011         if (err < 0)
1012                 return err;
1013
1014         switch (nf_ct_l3num(ct)) {
1015         case NFPROTO_IPV4:
1016                 err = nf_nat_ipv4_nlattr_to_range(tb, range);
1017                 break;
1018         case NFPROTO_IPV6:
1019                 err = nf_nat_ipv6_nlattr_to_range(tb, range);
1020                 break;
1021         default:
1022                 err = -EPROTONOSUPPORT;
1023                 break;
1024         }
1025
1026         if (err)
1027                 return err;
1028
1029         if (!tb[CTA_NAT_PROTO])
1030                 return 0;
1031
1032         return nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
1033 }
1034
1035 /* This function is called under rcu_read_lock() */
1036 static int
1037 nfnetlink_parse_nat_setup(struct nf_conn *ct,
1038                           enum nf_nat_manip_type manip,
1039                           const struct nlattr *attr)
1040 {
1041         struct nf_nat_range2 range;
1042         int err;
1043
1044         /* Should not happen, restricted to creating new conntracks
1045          * via ctnetlink.
1046          */
1047         if (WARN_ON_ONCE(nf_nat_initialized(ct, manip)))
1048                 return -EEXIST;
1049
1050         /* No NAT information has been passed, allocate the null-binding */
1051         if (attr == NULL)
1052                 return __nf_nat_alloc_null_binding(ct, manip) == NF_DROP ? -ENOMEM : 0;
1053
1054         err = nfnetlink_parse_nat(attr, ct, &range);
1055         if (err < 0)
1056                 return err;
1057
1058         return nf_nat_setup_info(ct, &range, manip) == NF_DROP ? -ENOMEM : 0;
1059 }
1060 #else
1061 static int
1062 nfnetlink_parse_nat_setup(struct nf_conn *ct,
1063                           enum nf_nat_manip_type manip,
1064                           const struct nlattr *attr)
1065 {
1066         return -EOPNOTSUPP;
1067 }
1068 #endif
1069
1070 static struct nf_ct_helper_expectfn follow_master_nat = {
1071         .name           = "nat-follow-master",
1072         .expectfn       = nf_nat_follow_master,
1073 };
1074
1075 int nf_nat_register_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
1076                        const struct nf_hook_ops *orig_nat_ops, unsigned int ops_count)
1077 {
1078         struct nat_net *nat_net = net_generic(net, nat_net_id);
1079         struct nf_nat_hooks_net *nat_proto_net;
1080         struct nf_nat_lookup_hook_priv *priv;
1081         unsigned int hooknum = ops->hooknum;
1082         struct nf_hook_ops *nat_ops;
1083         int i, ret;
1084
1085         if (WARN_ON_ONCE(pf >= ARRAY_SIZE(nat_net->nat_proto_net)))
1086                 return -EINVAL;
1087
1088         nat_proto_net = &nat_net->nat_proto_net[pf];
1089
1090         for (i = 0; i < ops_count; i++) {
1091                 if (orig_nat_ops[i].hooknum == hooknum) {
1092                         hooknum = i;
1093                         break;
1094                 }
1095         }
1096
1097         if (WARN_ON_ONCE(i == ops_count))
1098                 return -EINVAL;
1099
1100         mutex_lock(&nf_nat_proto_mutex);
1101         if (!nat_proto_net->nat_hook_ops) {
1102                 WARN_ON(nat_proto_net->users != 0);
1103
1104                 nat_ops = kmemdup(orig_nat_ops, sizeof(*orig_nat_ops) * ops_count, GFP_KERNEL);
1105                 if (!nat_ops) {
1106                         mutex_unlock(&nf_nat_proto_mutex);
1107                         return -ENOMEM;
1108                 }
1109
1110                 for (i = 0; i < ops_count; i++) {
1111                         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1112                         if (priv) {
1113                                 nat_ops[i].priv = priv;
1114                                 continue;
1115                         }
1116                         mutex_unlock(&nf_nat_proto_mutex);
1117                         while (i)
1118                                 kfree(nat_ops[--i].priv);
1119                         kfree(nat_ops);
1120                         return -ENOMEM;
1121                 }
1122
1123                 ret = nf_register_net_hooks(net, nat_ops, ops_count);
1124                 if (ret < 0) {
1125                         mutex_unlock(&nf_nat_proto_mutex);
1126                         for (i = 0; i < ops_count; i++)
1127                                 kfree(nat_ops[i].priv);
1128                         kfree(nat_ops);
1129                         return ret;
1130                 }
1131
1132                 nat_proto_net->nat_hook_ops = nat_ops;
1133         }
1134
1135         nat_ops = nat_proto_net->nat_hook_ops;
1136         priv = nat_ops[hooknum].priv;
1137         if (WARN_ON_ONCE(!priv)) {
1138                 mutex_unlock(&nf_nat_proto_mutex);
1139                 return -EOPNOTSUPP;
1140         }
1141
1142         ret = nf_hook_entries_insert_raw(&priv->entries, ops);
1143         if (ret == 0)
1144                 nat_proto_net->users++;
1145
1146         mutex_unlock(&nf_nat_proto_mutex);
1147         return ret;
1148 }
1149
1150 void nf_nat_unregister_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
1151                           unsigned int ops_count)
1152 {
1153         struct nat_net *nat_net = net_generic(net, nat_net_id);
1154         struct nf_nat_hooks_net *nat_proto_net;
1155         struct nf_nat_lookup_hook_priv *priv;
1156         struct nf_hook_ops *nat_ops;
1157         int hooknum = ops->hooknum;
1158         int i;
1159
1160         if (pf >= ARRAY_SIZE(nat_net->nat_proto_net))
1161                 return;
1162
1163         nat_proto_net = &nat_net->nat_proto_net[pf];
1164
1165         mutex_lock(&nf_nat_proto_mutex);
1166         if (WARN_ON(nat_proto_net->users == 0))
1167                 goto unlock;
1168
1169         nat_proto_net->users--;
1170
1171         nat_ops = nat_proto_net->nat_hook_ops;
1172         for (i = 0; i < ops_count; i++) {
1173                 if (nat_ops[i].hooknum == hooknum) {
1174                         hooknum = i;
1175                         break;
1176                 }
1177         }
1178         if (WARN_ON_ONCE(i == ops_count))
1179                 goto unlock;
1180         priv = nat_ops[hooknum].priv;
1181         nf_hook_entries_delete_raw(&priv->entries, ops);
1182
1183         if (nat_proto_net->users == 0) {
1184                 nf_unregister_net_hooks(net, nat_ops, ops_count);
1185
1186                 for (i = 0; i < ops_count; i++) {
1187                         priv = nat_ops[i].priv;
1188                         kfree_rcu(priv, rcu_head);
1189                 }
1190
1191                 nat_proto_net->nat_hook_ops = NULL;
1192                 kfree(nat_ops);
1193         }
1194 unlock:
1195         mutex_unlock(&nf_nat_proto_mutex);
1196 }
1197
1198 static struct pernet_operations nat_net_ops = {
1199         .id = &nat_net_id,
1200         .size = sizeof(struct nat_net),
1201 };
1202
1203 static const struct nf_nat_hook nat_hook = {
1204         .parse_nat_setup        = nfnetlink_parse_nat_setup,
1205 #ifdef CONFIG_XFRM
1206         .decode_session         = __nf_nat_decode_session,
1207 #endif
1208         .manip_pkt              = nf_nat_manip_pkt,
1209         .remove_nat_bysrc       = nf_nat_cleanup_conntrack,
1210 };
1211
1212 static int __init nf_nat_init(void)
1213 {
1214         int ret, i;
1215
1216         /* Leave them the same for the moment. */
1217         nf_nat_htable_size = nf_conntrack_htable_size;
1218         if (nf_nat_htable_size < CONNTRACK_LOCKS)
1219                 nf_nat_htable_size = CONNTRACK_LOCKS;
1220
1221         nf_nat_bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size, 0);
1222         if (!nf_nat_bysource)
1223                 return -ENOMEM;
1224
1225         for (i = 0; i < CONNTRACK_LOCKS; i++)
1226                 spin_lock_init(&nf_nat_locks[i]);
1227
1228         ret = register_pernet_subsys(&nat_net_ops);
1229         if (ret < 0) {
1230                 kvfree(nf_nat_bysource);
1231                 return ret;
1232         }
1233
1234         nf_ct_helper_expectfn_register(&follow_master_nat);
1235
1236         WARN_ON(nf_nat_hook != NULL);
1237         RCU_INIT_POINTER(nf_nat_hook, &nat_hook);
1238
1239         ret = register_nf_nat_bpf();
1240         if (ret < 0) {
1241                 RCU_INIT_POINTER(nf_nat_hook, NULL);
1242                 nf_ct_helper_expectfn_unregister(&follow_master_nat);
1243                 synchronize_net();
1244                 unregister_pernet_subsys(&nat_net_ops);
1245                 kvfree(nf_nat_bysource);
1246         }
1247
1248         return ret;
1249 }
1250
1251 static void __exit nf_nat_cleanup(void)
1252 {
1253         struct nf_nat_proto_clean clean = {};
1254
1255         nf_ct_iterate_destroy(nf_nat_proto_clean, &clean);
1256
1257         nf_ct_helper_expectfn_unregister(&follow_master_nat);
1258         RCU_INIT_POINTER(nf_nat_hook, NULL);
1259
1260         synchronize_net();
1261         kvfree(nf_nat_bysource);
1262         unregister_pernet_subsys(&nat_net_ops);
1263 }
1264
1265 MODULE_LICENSE("GPL");
1266
1267 module_init(nf_nat_init);
1268 module_exit(nf_nat_cleanup);