| 1 | /* |
| 2 | * IPv6 fragment reassembly |
| 3 | * Linux INET6 implementation |
| 4 | * |
| 5 | * Authors: |
| 6 | * Pedro Roque <roque@di.fc.ul.pt> |
| 7 | * |
| 8 | * Based on: net/ipv4/ip_fragment.c |
| 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 | /* |
| 17 | * Fixes: |
| 18 | * Andi Kleen Make it work with multiple hosts. |
| 19 | * More RFC compliance. |
| 20 | * |
| 21 | * Horst von Brand Add missing #include <linux/string.h> |
| 22 | * Alexey Kuznetsov SMP races, threading, cleanup. |
| 23 | * Patrick McHardy LRU queue of frag heads for evictor. |
| 24 | * Mitsuru KANDA @USAGI Register inet6_protocol{}. |
| 25 | * David Stevens and |
| 26 | * YOSHIFUJI,H. @USAGI Always remove fragment header to |
| 27 | * calculate ICV correctly. |
| 28 | */ |
| 29 | |
| 30 | #define pr_fmt(fmt) "IPv6: " fmt |
| 31 | |
| 32 | #include <linux/errno.h> |
| 33 | #include <linux/types.h> |
| 34 | #include <linux/string.h> |
| 35 | #include <linux/socket.h> |
| 36 | #include <linux/sockios.h> |
| 37 | #include <linux/jiffies.h> |
| 38 | #include <linux/net.h> |
| 39 | #include <linux/list.h> |
| 40 | #include <linux/netdevice.h> |
| 41 | #include <linux/in6.h> |
| 42 | #include <linux/ipv6.h> |
| 43 | #include <linux/icmpv6.h> |
| 44 | #include <linux/random.h> |
| 45 | #include <linux/jhash.h> |
| 46 | #include <linux/skbuff.h> |
| 47 | #include <linux/slab.h> |
| 48 | #include <linux/export.h> |
| 49 | |
| 50 | #include <net/sock.h> |
| 51 | #include <net/snmp.h> |
| 52 | |
| 53 | #include <net/ipv6.h> |
| 54 | #include <net/ip6_route.h> |
| 55 | #include <net/protocol.h> |
| 56 | #include <net/transp_v6.h> |
| 57 | #include <net/rawv6.h> |
| 58 | #include <net/ndisc.h> |
| 59 | #include <net/addrconf.h> |
| 60 | #include <net/inet_frag.h> |
| 61 | #include <net/inet_ecn.h> |
| 62 | |
| 63 | static const char ip6_frag_cache_name[] = "ip6-frags"; |
| 64 | |
| 65 | struct ip6frag_skb_cb { |
| 66 | struct inet6_skb_parm h; |
| 67 | int offset; |
| 68 | }; |
| 69 | |
| 70 | #define FRAG6_CB(skb) ((struct ip6frag_skb_cb *)((skb)->cb)) |
| 71 | |
| 72 | static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h) |
| 73 | { |
| 74 | return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK); |
| 75 | } |
| 76 | |
| 77 | static struct inet_frags ip6_frags; |
| 78 | |
| 79 | static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, |
| 80 | struct net_device *dev); |
| 81 | |
| 82 | /* |
| 83 | * callers should be careful not to use the hash value outside the ipfrag_lock |
| 84 | * as doing so could race with ipfrag_hash_rnd being recalculated. |
| 85 | */ |
| 86 | static unsigned int inet6_hash_frag(__be32 id, const struct in6_addr *saddr, |
| 87 | const struct in6_addr *daddr) |
| 88 | { |
| 89 | net_get_random_once(&ip6_frags.rnd, sizeof(ip6_frags.rnd)); |
| 90 | return jhash_3words(ipv6_addr_hash(saddr), ipv6_addr_hash(daddr), |
| 91 | (__force u32)id, ip6_frags.rnd); |
| 92 | } |
| 93 | |
| 94 | static unsigned int ip6_hashfn(const struct inet_frag_queue *q) |
| 95 | { |
| 96 | const struct frag_queue *fq; |
| 97 | |
| 98 | fq = container_of(q, struct frag_queue, q); |
| 99 | return inet6_hash_frag(fq->id, &fq->saddr, &fq->daddr); |
| 100 | } |
| 101 | |
| 102 | bool ip6_frag_match(const struct inet_frag_queue *q, const void *a) |
| 103 | { |
| 104 | const struct frag_queue *fq; |
| 105 | const struct ip6_create_arg *arg = a; |
| 106 | |
| 107 | fq = container_of(q, struct frag_queue, q); |
| 108 | return fq->id == arg->id && |
| 109 | fq->user == arg->user && |
| 110 | ipv6_addr_equal(&fq->saddr, arg->src) && |
| 111 | ipv6_addr_equal(&fq->daddr, arg->dst) && |
| 112 | (arg->iif == fq->iif || |
| 113 | !(ipv6_addr_type(arg->dst) & (IPV6_ADDR_MULTICAST | |
| 114 | IPV6_ADDR_LINKLOCAL))); |
| 115 | } |
| 116 | EXPORT_SYMBOL(ip6_frag_match); |
| 117 | |
| 118 | void ip6_frag_init(struct inet_frag_queue *q, const void *a) |
| 119 | { |
| 120 | struct frag_queue *fq = container_of(q, struct frag_queue, q); |
| 121 | const struct ip6_create_arg *arg = a; |
| 122 | |
| 123 | fq->id = arg->id; |
| 124 | fq->user = arg->user; |
| 125 | fq->saddr = *arg->src; |
| 126 | fq->daddr = *arg->dst; |
| 127 | fq->ecn = arg->ecn; |
| 128 | } |
| 129 | EXPORT_SYMBOL(ip6_frag_init); |
| 130 | |
| 131 | void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq, |
| 132 | struct inet_frags *frags) |
| 133 | { |
| 134 | struct net_device *dev = NULL; |
| 135 | |
| 136 | spin_lock(&fq->q.lock); |
| 137 | |
| 138 | if (fq->q.flags & INET_FRAG_COMPLETE) |
| 139 | goto out; |
| 140 | |
| 141 | inet_frag_kill(&fq->q, frags); |
| 142 | |
| 143 | rcu_read_lock(); |
| 144 | dev = dev_get_by_index_rcu(net, fq->iif); |
| 145 | if (!dev) |
| 146 | goto out_rcu_unlock; |
| 147 | |
| 148 | __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); |
| 149 | |
| 150 | if (inet_frag_evicting(&fq->q)) |
| 151 | goto out_rcu_unlock; |
| 152 | |
| 153 | __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT); |
| 154 | |
| 155 | /* Don't send error if the first segment did not arrive. */ |
| 156 | if (!(fq->q.flags & INET_FRAG_FIRST_IN) || !fq->q.fragments) |
| 157 | goto out_rcu_unlock; |
| 158 | |
| 159 | /* But use as source device on which LAST ARRIVED |
| 160 | * segment was received. And do not use fq->dev |
| 161 | * pointer directly, device might already disappeared. |
| 162 | */ |
| 163 | fq->q.fragments->dev = dev; |
| 164 | icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0); |
| 165 | out_rcu_unlock: |
| 166 | rcu_read_unlock(); |
| 167 | out: |
| 168 | spin_unlock(&fq->q.lock); |
| 169 | inet_frag_put(&fq->q, frags); |
| 170 | } |
| 171 | EXPORT_SYMBOL(ip6_expire_frag_queue); |
| 172 | |
| 173 | static void ip6_frag_expire(unsigned long data) |
| 174 | { |
| 175 | struct frag_queue *fq; |
| 176 | struct net *net; |
| 177 | |
| 178 | fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q); |
| 179 | net = container_of(fq->q.net, struct net, ipv6.frags); |
| 180 | |
| 181 | ip6_expire_frag_queue(net, fq, &ip6_frags); |
| 182 | } |
| 183 | |
| 184 | static struct frag_queue * |
| 185 | fq_find(struct net *net, __be32 id, const struct in6_addr *src, |
| 186 | const struct in6_addr *dst, int iif, u8 ecn) |
| 187 | { |
| 188 | struct inet_frag_queue *q; |
| 189 | struct ip6_create_arg arg; |
| 190 | unsigned int hash; |
| 191 | |
| 192 | arg.id = id; |
| 193 | arg.user = IP6_DEFRAG_LOCAL_DELIVER; |
| 194 | arg.src = src; |
| 195 | arg.dst = dst; |
| 196 | arg.iif = iif; |
| 197 | arg.ecn = ecn; |
| 198 | |
| 199 | hash = inet6_hash_frag(id, src, dst); |
| 200 | |
| 201 | q = inet_frag_find(&net->ipv6.frags, &ip6_frags, &arg, hash); |
| 202 | if (IS_ERR_OR_NULL(q)) { |
| 203 | inet_frag_maybe_warn_overflow(q, pr_fmt()); |
| 204 | return NULL; |
| 205 | } |
| 206 | return container_of(q, struct frag_queue, q); |
| 207 | } |
| 208 | |
| 209 | static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, |
| 210 | struct frag_hdr *fhdr, int nhoff) |
| 211 | { |
| 212 | struct sk_buff *prev, *next; |
| 213 | struct net_device *dev; |
| 214 | int offset, end; |
| 215 | struct net *net = dev_net(skb_dst(skb)->dev); |
| 216 | u8 ecn; |
| 217 | |
| 218 | if (fq->q.flags & INET_FRAG_COMPLETE) |
| 219 | goto err; |
| 220 | |
| 221 | offset = ntohs(fhdr->frag_off) & ~0x7; |
| 222 | end = offset + (ntohs(ipv6_hdr(skb)->payload_len) - |
| 223 | ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1))); |
| 224 | |
| 225 | if ((unsigned int)end > IPV6_MAXPLEN) { |
| 226 | __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), |
| 227 | IPSTATS_MIB_INHDRERRORS); |
| 228 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, |
| 229 | ((u8 *)&fhdr->frag_off - |
| 230 | skb_network_header(skb))); |
| 231 | return -1; |
| 232 | } |
| 233 | |
| 234 | ecn = ip6_frag_ecn(ipv6_hdr(skb)); |
| 235 | |
| 236 | if (skb->ip_summed == CHECKSUM_COMPLETE) { |
| 237 | const unsigned char *nh = skb_network_header(skb); |
| 238 | skb->csum = csum_sub(skb->csum, |
| 239 | csum_partial(nh, (u8 *)(fhdr + 1) - nh, |
| 240 | 0)); |
| 241 | } |
| 242 | |
| 243 | /* Is this the final fragment? */ |
| 244 | if (!(fhdr->frag_off & htons(IP6_MF))) { |
| 245 | /* If we already have some bits beyond end |
| 246 | * or have different end, the segment is corrupted. |
| 247 | */ |
| 248 | if (end < fq->q.len || |
| 249 | ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len)) |
| 250 | goto err; |
| 251 | fq->q.flags |= INET_FRAG_LAST_IN; |
| 252 | fq->q.len = end; |
| 253 | } else { |
| 254 | /* Check if the fragment is rounded to 8 bytes. |
| 255 | * Required by the RFC. |
| 256 | */ |
| 257 | if (end & 0x7) { |
| 258 | /* RFC2460 says always send parameter problem in |
| 259 | * this case. -DaveM |
| 260 | */ |
| 261 | __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), |
| 262 | IPSTATS_MIB_INHDRERRORS); |
| 263 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, |
| 264 | offsetof(struct ipv6hdr, payload_len)); |
| 265 | return -1; |
| 266 | } |
| 267 | if (end > fq->q.len) { |
| 268 | /* Some bits beyond end -> corruption. */ |
| 269 | if (fq->q.flags & INET_FRAG_LAST_IN) |
| 270 | goto err; |
| 271 | fq->q.len = end; |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | if (end == offset) |
| 276 | goto err; |
| 277 | |
| 278 | /* Point into the IP datagram 'data' part. */ |
| 279 | if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) |
| 280 | goto err; |
| 281 | |
| 282 | if (pskb_trim_rcsum(skb, end - offset)) |
| 283 | goto err; |
| 284 | |
| 285 | /* Find out which fragments are in front and at the back of us |
| 286 | * in the chain of fragments so far. We must know where to put |
| 287 | * this fragment, right? |
| 288 | */ |
| 289 | prev = fq->q.fragments_tail; |
| 290 | if (!prev || FRAG6_CB(prev)->offset < offset) { |
| 291 | next = NULL; |
| 292 | goto found; |
| 293 | } |
| 294 | prev = NULL; |
| 295 | for (next = fq->q.fragments; next != NULL; next = next->next) { |
| 296 | if (FRAG6_CB(next)->offset >= offset) |
| 297 | break; /* bingo! */ |
| 298 | prev = next; |
| 299 | } |
| 300 | |
| 301 | found: |
| 302 | /* RFC5722, Section 4, amended by Errata ID : 3089 |
| 303 | * When reassembling an IPv6 datagram, if |
| 304 | * one or more its constituent fragments is determined to be an |
| 305 | * overlapping fragment, the entire datagram (and any constituent |
| 306 | * fragments) MUST be silently discarded. |
| 307 | */ |
| 308 | |
| 309 | /* Check for overlap with preceding fragment. */ |
| 310 | if (prev && |
| 311 | (FRAG6_CB(prev)->offset + prev->len) > offset) |
| 312 | goto discard_fq; |
| 313 | |
| 314 | /* Look for overlap with succeeding segment. */ |
| 315 | if (next && FRAG6_CB(next)->offset < end) |
| 316 | goto discard_fq; |
| 317 | |
| 318 | FRAG6_CB(skb)->offset = offset; |
| 319 | |
| 320 | /* Insert this fragment in the chain of fragments. */ |
| 321 | skb->next = next; |
| 322 | if (!next) |
| 323 | fq->q.fragments_tail = skb; |
| 324 | if (prev) |
| 325 | prev->next = skb; |
| 326 | else |
| 327 | fq->q.fragments = skb; |
| 328 | |
| 329 | dev = skb->dev; |
| 330 | if (dev) { |
| 331 | fq->iif = dev->ifindex; |
| 332 | skb->dev = NULL; |
| 333 | } |
| 334 | fq->q.stamp = skb->tstamp; |
| 335 | fq->q.meat += skb->len; |
| 336 | fq->ecn |= ecn; |
| 337 | add_frag_mem_limit(fq->q.net, skb->truesize); |
| 338 | |
| 339 | /* The first fragment. |
| 340 | * nhoffset is obtained from the first fragment, of course. |
| 341 | */ |
| 342 | if (offset == 0) { |
| 343 | fq->nhoffset = nhoff; |
| 344 | fq->q.flags |= INET_FRAG_FIRST_IN; |
| 345 | } |
| 346 | |
| 347 | if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && |
| 348 | fq->q.meat == fq->q.len) { |
| 349 | int res; |
| 350 | unsigned long orefdst = skb->_skb_refdst; |
| 351 | |
| 352 | skb->_skb_refdst = 0UL; |
| 353 | res = ip6_frag_reasm(fq, prev, dev); |
| 354 | skb->_skb_refdst = orefdst; |
| 355 | return res; |
| 356 | } |
| 357 | |
| 358 | skb_dst_drop(skb); |
| 359 | return -1; |
| 360 | |
| 361 | discard_fq: |
| 362 | inet_frag_kill(&fq->q, &ip6_frags); |
| 363 | err: |
| 364 | __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), |
| 365 | IPSTATS_MIB_REASMFAILS); |
| 366 | kfree_skb(skb); |
| 367 | return -1; |
| 368 | } |
| 369 | |
| 370 | /* |
| 371 | * Check if this packet is complete. |
| 372 | * Returns NULL on failure by any reason, and pointer |
| 373 | * to current nexthdr field in reassembled frame. |
| 374 | * |
| 375 | * It is called with locked fq, and caller must check that |
| 376 | * queue is eligible for reassembly i.e. it is not COMPLETE, |
| 377 | * the last and the first frames arrived and all the bits are here. |
| 378 | */ |
| 379 | static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, |
| 380 | struct net_device *dev) |
| 381 | { |
| 382 | struct net *net = container_of(fq->q.net, struct net, ipv6.frags); |
| 383 | struct sk_buff *fp, *head = fq->q.fragments; |
| 384 | int payload_len; |
| 385 | unsigned int nhoff; |
| 386 | int sum_truesize; |
| 387 | u8 ecn; |
| 388 | |
| 389 | inet_frag_kill(&fq->q, &ip6_frags); |
| 390 | |
| 391 | ecn = ip_frag_ecn_table[fq->ecn]; |
| 392 | if (unlikely(ecn == 0xff)) |
| 393 | goto out_fail; |
| 394 | |
| 395 | /* Make the one we just received the head. */ |
| 396 | if (prev) { |
| 397 | head = prev->next; |
| 398 | fp = skb_clone(head, GFP_ATOMIC); |
| 399 | |
| 400 | if (!fp) |
| 401 | goto out_oom; |
| 402 | |
| 403 | fp->next = head->next; |
| 404 | if (!fp->next) |
| 405 | fq->q.fragments_tail = fp; |
| 406 | prev->next = fp; |
| 407 | |
| 408 | skb_morph(head, fq->q.fragments); |
| 409 | head->next = fq->q.fragments->next; |
| 410 | |
| 411 | consume_skb(fq->q.fragments); |
| 412 | fq->q.fragments = head; |
| 413 | } |
| 414 | |
| 415 | WARN_ON(head == NULL); |
| 416 | WARN_ON(FRAG6_CB(head)->offset != 0); |
| 417 | |
| 418 | /* Unfragmented part is taken from the first segment. */ |
| 419 | payload_len = ((head->data - skb_network_header(head)) - |
| 420 | sizeof(struct ipv6hdr) + fq->q.len - |
| 421 | sizeof(struct frag_hdr)); |
| 422 | if (payload_len > IPV6_MAXPLEN) |
| 423 | goto out_oversize; |
| 424 | |
| 425 | /* Head of list must not be cloned. */ |
| 426 | if (skb_unclone(head, GFP_ATOMIC)) |
| 427 | goto out_oom; |
| 428 | |
| 429 | /* If the first fragment is fragmented itself, we split |
| 430 | * it to two chunks: the first with data and paged part |
| 431 | * and the second, holding only fragments. */ |
| 432 | if (skb_has_frag_list(head)) { |
| 433 | struct sk_buff *clone; |
| 434 | int i, plen = 0; |
| 435 | |
| 436 | clone = alloc_skb(0, GFP_ATOMIC); |
| 437 | if (!clone) |
| 438 | goto out_oom; |
| 439 | clone->next = head->next; |
| 440 | head->next = clone; |
| 441 | skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; |
| 442 | skb_frag_list_init(head); |
| 443 | for (i = 0; i < skb_shinfo(head)->nr_frags; i++) |
| 444 | plen += skb_frag_size(&skb_shinfo(head)->frags[i]); |
| 445 | clone->len = clone->data_len = head->data_len - plen; |
| 446 | head->data_len -= clone->len; |
| 447 | head->len -= clone->len; |
| 448 | clone->csum = 0; |
| 449 | clone->ip_summed = head->ip_summed; |
| 450 | add_frag_mem_limit(fq->q.net, clone->truesize); |
| 451 | } |
| 452 | |
| 453 | /* We have to remove fragment header from datagram and to relocate |
| 454 | * header in order to calculate ICV correctly. */ |
| 455 | nhoff = fq->nhoffset; |
| 456 | skb_network_header(head)[nhoff] = skb_transport_header(head)[0]; |
| 457 | memmove(head->head + sizeof(struct frag_hdr), head->head, |
| 458 | (head->data - head->head) - sizeof(struct frag_hdr)); |
| 459 | head->mac_header += sizeof(struct frag_hdr); |
| 460 | head->network_header += sizeof(struct frag_hdr); |
| 461 | |
| 462 | skb_reset_transport_header(head); |
| 463 | skb_push(head, head->data - skb_network_header(head)); |
| 464 | |
| 465 | sum_truesize = head->truesize; |
| 466 | for (fp = head->next; fp;) { |
| 467 | bool headstolen; |
| 468 | int delta; |
| 469 | struct sk_buff *next = fp->next; |
| 470 | |
| 471 | sum_truesize += fp->truesize; |
| 472 | if (head->ip_summed != fp->ip_summed) |
| 473 | head->ip_summed = CHECKSUM_NONE; |
| 474 | else if (head->ip_summed == CHECKSUM_COMPLETE) |
| 475 | head->csum = csum_add(head->csum, fp->csum); |
| 476 | |
| 477 | if (skb_try_coalesce(head, fp, &headstolen, &delta)) { |
| 478 | kfree_skb_partial(fp, headstolen); |
| 479 | } else { |
| 480 | if (!skb_shinfo(head)->frag_list) |
| 481 | skb_shinfo(head)->frag_list = fp; |
| 482 | head->data_len += fp->len; |
| 483 | head->len += fp->len; |
| 484 | head->truesize += fp->truesize; |
| 485 | } |
| 486 | fp = next; |
| 487 | } |
| 488 | sub_frag_mem_limit(fq->q.net, sum_truesize); |
| 489 | |
| 490 | head->next = NULL; |
| 491 | head->dev = dev; |
| 492 | head->tstamp = fq->q.stamp; |
| 493 | ipv6_hdr(head)->payload_len = htons(payload_len); |
| 494 | ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn); |
| 495 | IP6CB(head)->nhoff = nhoff; |
| 496 | IP6CB(head)->flags |= IP6SKB_FRAGMENTED; |
| 497 | |
| 498 | /* Yes, and fold redundant checksum back. 8) */ |
| 499 | skb_postpush_rcsum(head, skb_network_header(head), |
| 500 | skb_network_header_len(head)); |
| 501 | |
| 502 | rcu_read_lock(); |
| 503 | __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS); |
| 504 | rcu_read_unlock(); |
| 505 | fq->q.fragments = NULL; |
| 506 | fq->q.fragments_tail = NULL; |
| 507 | return 1; |
| 508 | |
| 509 | out_oversize: |
| 510 | net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len); |
| 511 | goto out_fail; |
| 512 | out_oom: |
| 513 | net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n"); |
| 514 | out_fail: |
| 515 | rcu_read_lock(); |
| 516 | __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); |
| 517 | rcu_read_unlock(); |
| 518 | return -1; |
| 519 | } |
| 520 | |
| 521 | static int ipv6_frag_rcv(struct sk_buff *skb) |
| 522 | { |
| 523 | struct frag_hdr *fhdr; |
| 524 | struct frag_queue *fq; |
| 525 | const struct ipv6hdr *hdr = ipv6_hdr(skb); |
| 526 | struct net *net = dev_net(skb_dst(skb)->dev); |
| 527 | |
| 528 | if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED) |
| 529 | goto fail_hdr; |
| 530 | |
| 531 | __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS); |
| 532 | |
| 533 | /* Jumbo payload inhibits frag. header */ |
| 534 | if (hdr->payload_len == 0) |
| 535 | goto fail_hdr; |
| 536 | |
| 537 | if (!pskb_may_pull(skb, (skb_transport_offset(skb) + |
| 538 | sizeof(struct frag_hdr)))) |
| 539 | goto fail_hdr; |
| 540 | |
| 541 | hdr = ipv6_hdr(skb); |
| 542 | fhdr = (struct frag_hdr *)skb_transport_header(skb); |
| 543 | |
| 544 | if (!(fhdr->frag_off & htons(0xFFF9))) { |
| 545 | /* It is not a fragmented frame */ |
| 546 | skb->transport_header += sizeof(struct frag_hdr); |
| 547 | __IP6_INC_STATS(net, |
| 548 | ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS); |
| 549 | |
| 550 | IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb); |
| 551 | IP6CB(skb)->flags |= IP6SKB_FRAGMENTED; |
| 552 | return 1; |
| 553 | } |
| 554 | |
| 555 | fq = fq_find(net, fhdr->identification, &hdr->saddr, &hdr->daddr, |
| 556 | skb->dev ? skb->dev->ifindex : 0, ip6_frag_ecn(hdr)); |
| 557 | if (fq) { |
| 558 | int ret; |
| 559 | |
| 560 | spin_lock(&fq->q.lock); |
| 561 | |
| 562 | ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); |
| 563 | |
| 564 | spin_unlock(&fq->q.lock); |
| 565 | inet_frag_put(&fq->q, &ip6_frags); |
| 566 | return ret; |
| 567 | } |
| 568 | |
| 569 | __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS); |
| 570 | kfree_skb(skb); |
| 571 | return -1; |
| 572 | |
| 573 | fail_hdr: |
| 574 | __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), |
| 575 | IPSTATS_MIB_INHDRERRORS); |
| 576 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb)); |
| 577 | return -1; |
| 578 | } |
| 579 | |
| 580 | static const struct inet6_protocol frag_protocol = { |
| 581 | .handler = ipv6_frag_rcv, |
| 582 | .flags = INET6_PROTO_NOPOLICY, |
| 583 | }; |
| 584 | |
| 585 | #ifdef CONFIG_SYSCTL |
| 586 | static int zero; |
| 587 | |
| 588 | static struct ctl_table ip6_frags_ns_ctl_table[] = { |
| 589 | { |
| 590 | .procname = "ip6frag_high_thresh", |
| 591 | .data = &init_net.ipv6.frags.high_thresh, |
| 592 | .maxlen = sizeof(int), |
| 593 | .mode = 0644, |
| 594 | .proc_handler = proc_dointvec_minmax, |
| 595 | .extra1 = &init_net.ipv6.frags.low_thresh |
| 596 | }, |
| 597 | { |
| 598 | .procname = "ip6frag_low_thresh", |
| 599 | .data = &init_net.ipv6.frags.low_thresh, |
| 600 | .maxlen = sizeof(int), |
| 601 | .mode = 0644, |
| 602 | .proc_handler = proc_dointvec_minmax, |
| 603 | .extra1 = &zero, |
| 604 | .extra2 = &init_net.ipv6.frags.high_thresh |
| 605 | }, |
| 606 | { |
| 607 | .procname = "ip6frag_time", |
| 608 | .data = &init_net.ipv6.frags.timeout, |
| 609 | .maxlen = sizeof(int), |
| 610 | .mode = 0644, |
| 611 | .proc_handler = proc_dointvec_jiffies, |
| 612 | }, |
| 613 | { } |
| 614 | }; |
| 615 | |
| 616 | /* secret interval has been deprecated */ |
| 617 | static int ip6_frags_secret_interval_unused; |
| 618 | static struct ctl_table ip6_frags_ctl_table[] = { |
| 619 | { |
| 620 | .procname = "ip6frag_secret_interval", |
| 621 | .data = &ip6_frags_secret_interval_unused, |
| 622 | .maxlen = sizeof(int), |
| 623 | .mode = 0644, |
| 624 | .proc_handler = proc_dointvec_jiffies, |
| 625 | }, |
| 626 | { } |
| 627 | }; |
| 628 | |
| 629 | static int __net_init ip6_frags_ns_sysctl_register(struct net *net) |
| 630 | { |
| 631 | struct ctl_table *table; |
| 632 | struct ctl_table_header *hdr; |
| 633 | |
| 634 | table = ip6_frags_ns_ctl_table; |
| 635 | if (!net_eq(net, &init_net)) { |
| 636 | table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL); |
| 637 | if (!table) |
| 638 | goto err_alloc; |
| 639 | |
| 640 | table[0].data = &net->ipv6.frags.high_thresh; |
| 641 | table[0].extra1 = &net->ipv6.frags.low_thresh; |
| 642 | table[0].extra2 = &init_net.ipv6.frags.high_thresh; |
| 643 | table[1].data = &net->ipv6.frags.low_thresh; |
| 644 | table[1].extra2 = &net->ipv6.frags.high_thresh; |
| 645 | table[2].data = &net->ipv6.frags.timeout; |
| 646 | |
| 647 | /* Don't export sysctls to unprivileged users */ |
| 648 | if (net->user_ns != &init_user_ns) |
| 649 | table[0].procname = NULL; |
| 650 | } |
| 651 | |
| 652 | hdr = register_net_sysctl(net, "net/ipv6", table); |
| 653 | if (!hdr) |
| 654 | goto err_reg; |
| 655 | |
| 656 | net->ipv6.sysctl.frags_hdr = hdr; |
| 657 | return 0; |
| 658 | |
| 659 | err_reg: |
| 660 | if (!net_eq(net, &init_net)) |
| 661 | kfree(table); |
| 662 | err_alloc: |
| 663 | return -ENOMEM; |
| 664 | } |
| 665 | |
| 666 | static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net) |
| 667 | { |
| 668 | struct ctl_table *table; |
| 669 | |
| 670 | table = net->ipv6.sysctl.frags_hdr->ctl_table_arg; |
| 671 | unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr); |
| 672 | if (!net_eq(net, &init_net)) |
| 673 | kfree(table); |
| 674 | } |
| 675 | |
| 676 | static struct ctl_table_header *ip6_ctl_header; |
| 677 | |
| 678 | static int ip6_frags_sysctl_register(void) |
| 679 | { |
| 680 | ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6", |
| 681 | ip6_frags_ctl_table); |
| 682 | return ip6_ctl_header == NULL ? -ENOMEM : 0; |
| 683 | } |
| 684 | |
| 685 | static void ip6_frags_sysctl_unregister(void) |
| 686 | { |
| 687 | unregister_net_sysctl_table(ip6_ctl_header); |
| 688 | } |
| 689 | #else |
| 690 | static int ip6_frags_ns_sysctl_register(struct net *net) |
| 691 | { |
| 692 | return 0; |
| 693 | } |
| 694 | |
| 695 | static void ip6_frags_ns_sysctl_unregister(struct net *net) |
| 696 | { |
| 697 | } |
| 698 | |
| 699 | static int ip6_frags_sysctl_register(void) |
| 700 | { |
| 701 | return 0; |
| 702 | } |
| 703 | |
| 704 | static void ip6_frags_sysctl_unregister(void) |
| 705 | { |
| 706 | } |
| 707 | #endif |
| 708 | |
| 709 | static int __net_init ipv6_frags_init_net(struct net *net) |
| 710 | { |
| 711 | int res; |
| 712 | |
| 713 | net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH; |
| 714 | net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH; |
| 715 | net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT; |
| 716 | |
| 717 | res = inet_frags_init_net(&net->ipv6.frags); |
| 718 | if (res) |
| 719 | return res; |
| 720 | res = ip6_frags_ns_sysctl_register(net); |
| 721 | if (res) |
| 722 | inet_frags_uninit_net(&net->ipv6.frags); |
| 723 | return res; |
| 724 | } |
| 725 | |
| 726 | static void __net_exit ipv6_frags_exit_net(struct net *net) |
| 727 | { |
| 728 | ip6_frags_ns_sysctl_unregister(net); |
| 729 | inet_frags_exit_net(&net->ipv6.frags, &ip6_frags); |
| 730 | } |
| 731 | |
| 732 | static struct pernet_operations ip6_frags_ops = { |
| 733 | .init = ipv6_frags_init_net, |
| 734 | .exit = ipv6_frags_exit_net, |
| 735 | }; |
| 736 | |
| 737 | int __init ipv6_frag_init(void) |
| 738 | { |
| 739 | int ret; |
| 740 | |
| 741 | ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT); |
| 742 | if (ret) |
| 743 | goto out; |
| 744 | |
| 745 | ret = ip6_frags_sysctl_register(); |
| 746 | if (ret) |
| 747 | goto err_sysctl; |
| 748 | |
| 749 | ret = register_pernet_subsys(&ip6_frags_ops); |
| 750 | if (ret) |
| 751 | goto err_pernet; |
| 752 | |
| 753 | ip6_frags.hashfn = ip6_hashfn; |
| 754 | ip6_frags.constructor = ip6_frag_init; |
| 755 | ip6_frags.destructor = NULL; |
| 756 | ip6_frags.qsize = sizeof(struct frag_queue); |
| 757 | ip6_frags.match = ip6_frag_match; |
| 758 | ip6_frags.frag_expire = ip6_frag_expire; |
| 759 | ip6_frags.frags_cache_name = ip6_frag_cache_name; |
| 760 | ret = inet_frags_init(&ip6_frags); |
| 761 | if (ret) |
| 762 | goto err_pernet; |
| 763 | out: |
| 764 | return ret; |
| 765 | |
| 766 | err_pernet: |
| 767 | ip6_frags_sysctl_unregister(); |
| 768 | err_sysctl: |
| 769 | inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT); |
| 770 | goto out; |
| 771 | } |
| 772 | |
| 773 | void ipv6_frag_exit(void) |
| 774 | { |
| 775 | inet_frags_fini(&ip6_frags); |
| 776 | ip6_frags_sysctl_unregister(); |
| 777 | unregister_pernet_subsys(&ip6_frags_ops); |
| 778 | inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT); |
| 779 | } |