1 /* 2 * IPv6 fragment reassembly 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * $Id: reassembly.c,v 1.26 2001/03/07 22:00:57 davem Exp $ 9 * 10 * Based on: net/ipv4/ip_fragment.c 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 18 /* 19 * Fixes: 20 * Andi Kleen Make it work with multiple hosts. 21 * More RFC compliance. 22 * 23 * Horst von Brand Add missing #include <linux/string.h> 24 * Alexey Kuznetsov SMP races, threading, cleanup. 25 * Patrick McHardy LRU queue of frag heads for evictor. 26 * Mitsuru KANDA @USAGI Register inet6_protocol{}. 27 * David Stevens and 28 * YOSHIFUJI,H. @USAGI Always remove fragment header to 29 * calculate ICV correctly. 30 */ 31 #include <linux/errno.h> 32 #include <linux/types.h> 33 #include <linux/string.h> 34 #include <linux/socket.h> 35 #include <linux/sockios.h> 36 #include <linux/jiffies.h> 37 #include <linux/net.h> 38 #include <linux/list.h> 39 #include <linux/netdevice.h> 40 #include <linux/in6.h> 41 #include <linux/ipv6.h> 42 #include <linux/icmpv6.h> 43 #include <linux/random.h> 44 #include <linux/jhash.h> 45 #include <linux/skbuff.h> 46 47 #include <net/sock.h> 48 #include <net/snmp.h> 49 50 #include <net/ipv6.h> 51 #include <net/ip6_route.h> 52 #include <net/protocol.h> 53 #include <net/transp_v6.h> 54 #include <net/rawv6.h> 55 #include <net/ndisc.h> 56 #include <net/addrconf.h> 57 #include <net/inet_frag.h> 58 59 struct ip6frag_skb_cb 60 { 61 struct inet6_skb_parm h; 62 int offset; 63 }; 64 65 #define FRAG6_CB(skb) ((struct ip6frag_skb_cb*)((skb)->cb)) 66 67 68 /* 69 * Equivalent of ipv4 struct ipq 70 */ 71 72 struct frag_queue 73 { 74 struct inet_frag_queue q; 75 76 __be32 id; /* fragment id */ 77 struct in6_addr saddr; 78 struct in6_addr daddr; 79 80 int iif; 81 unsigned int csum; 82 __u16 nhoffset; 83 }; 84 85 struct inet_frags_ctl ip6_frags_ctl __read_mostly = { 86 .high_thresh = 256 * 1024, 87 .low_thresh = 192 * 1024, 88 .timeout = IPV6_FRAG_TIMEOUT, 89 .secret_interval = 10 * 60 * HZ, 90 }; 91 92 static struct inet_frags ip6_frags; 93 94 int ip6_frag_nqueues(void) 95 { 96 return ip6_frags.nqueues; 97 } 98 99 int ip6_frag_mem(void) 100 { 101 return atomic_read(&ip6_frags.mem); 102 } 103 104 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 105 struct net_device *dev); 106 107 static __inline__ void __fq_unlink(struct frag_queue *fq) 108 { 109 hlist_del(&fq->q.list); 110 list_del(&fq->q.lru_list); 111 ip6_frags.nqueues--; 112 } 113 114 static __inline__ void fq_unlink(struct frag_queue *fq) 115 { 116 write_lock(&ip6_frags.lock); 117 __fq_unlink(fq); 118 write_unlock(&ip6_frags.lock); 119 } 120 121 /* 122 * callers should be careful not to use the hash value outside the ipfrag_lock 123 * as doing so could race with ipfrag_hash_rnd being recalculated. 124 */ 125 static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr, 126 struct in6_addr *daddr) 127 { 128 u32 a, b, c; 129 130 a = (__force u32)saddr->s6_addr32[0]; 131 b = (__force u32)saddr->s6_addr32[1]; 132 c = (__force u32)saddr->s6_addr32[2]; 133 134 a += JHASH_GOLDEN_RATIO; 135 b += JHASH_GOLDEN_RATIO; 136 c += ip6_frags.rnd; 137 __jhash_mix(a, b, c); 138 139 a += (__force u32)saddr->s6_addr32[3]; 140 b += (__force u32)daddr->s6_addr32[0]; 141 c += (__force u32)daddr->s6_addr32[1]; 142 __jhash_mix(a, b, c); 143 144 a += (__force u32)daddr->s6_addr32[2]; 145 b += (__force u32)daddr->s6_addr32[3]; 146 c += (__force u32)id; 147 __jhash_mix(a, b, c); 148 149 return c & (INETFRAGS_HASHSZ - 1); 150 } 151 152 static void ip6_frag_secret_rebuild(unsigned long dummy) 153 { 154 unsigned long now = jiffies; 155 int i; 156 157 write_lock(&ip6_frags.lock); 158 get_random_bytes(&ip6_frags.rnd, sizeof(u32)); 159 for (i = 0; i < INETFRAGS_HASHSZ; i++) { 160 struct frag_queue *q; 161 struct hlist_node *p, *n; 162 163 hlist_for_each_entry_safe(q, p, n, &ip6_frags.hash[i], q.list) { 164 unsigned int hval = ip6qhashfn(q->id, 165 &q->saddr, 166 &q->daddr); 167 168 if (hval != i) { 169 hlist_del(&q->q.list); 170 171 /* Relink to new hash chain. */ 172 hlist_add_head(&q->q.list, 173 &ip6_frags.hash[hval]); 174 175 } 176 } 177 } 178 write_unlock(&ip6_frags.lock); 179 180 mod_timer(&ip6_frags.secret_timer, now + ip6_frags_ctl.secret_interval); 181 } 182 183 /* Memory Tracking Functions. */ 184 static inline void frag_kfree_skb(struct sk_buff *skb, int *work) 185 { 186 if (work) 187 *work -= skb->truesize; 188 atomic_sub(skb->truesize, &ip6_frags.mem); 189 kfree_skb(skb); 190 } 191 192 static inline void frag_free_queue(struct frag_queue *fq, int *work) 193 { 194 if (work) 195 *work -= sizeof(struct frag_queue); 196 atomic_sub(sizeof(struct frag_queue), &ip6_frags.mem); 197 kfree(fq); 198 } 199 200 static inline struct frag_queue *frag_alloc_queue(void) 201 { 202 struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC); 203 204 if(!fq) 205 return NULL; 206 atomic_add(sizeof(struct frag_queue), &ip6_frags.mem); 207 return fq; 208 } 209 210 /* Destruction primitives. */ 211 212 /* Complete destruction of fq. */ 213 static void ip6_frag_destroy(struct frag_queue *fq, int *work) 214 { 215 struct sk_buff *fp; 216 217 BUG_TRAP(fq->q.last_in&COMPLETE); 218 BUG_TRAP(del_timer(&fq->q.timer) == 0); 219 220 /* Release all fragment data. */ 221 fp = fq->q.fragments; 222 while (fp) { 223 struct sk_buff *xp = fp->next; 224 225 frag_kfree_skb(fp, work); 226 fp = xp; 227 } 228 229 frag_free_queue(fq, work); 230 } 231 232 static __inline__ void fq_put(struct frag_queue *fq, int *work) 233 { 234 if (atomic_dec_and_test(&fq->q.refcnt)) 235 ip6_frag_destroy(fq, work); 236 } 237 238 /* Kill fq entry. It is not destroyed immediately, 239 * because caller (and someone more) holds reference count. 240 */ 241 static __inline__ void fq_kill(struct frag_queue *fq) 242 { 243 if (del_timer(&fq->q.timer)) 244 atomic_dec(&fq->q.refcnt); 245 246 if (!(fq->q.last_in & COMPLETE)) { 247 fq_unlink(fq); 248 atomic_dec(&fq->q.refcnt); 249 fq->q.last_in |= COMPLETE; 250 } 251 } 252 253 static void ip6_evictor(struct inet6_dev *idev) 254 { 255 struct frag_queue *fq; 256 struct list_head *tmp; 257 int work; 258 259 work = atomic_read(&ip6_frags.mem) - ip6_frags_ctl.low_thresh; 260 if (work <= 0) 261 return; 262 263 while(work > 0) { 264 read_lock(&ip6_frags.lock); 265 if (list_empty(&ip6_frags.lru_list)) { 266 read_unlock(&ip6_frags.lock); 267 return; 268 } 269 tmp = ip6_frags.lru_list.next; 270 fq = list_entry(tmp, struct frag_queue, q.lru_list); 271 atomic_inc(&fq->q.refcnt); 272 read_unlock(&ip6_frags.lock); 273 274 spin_lock(&fq->q.lock); 275 if (!(fq->q.last_in&COMPLETE)) 276 fq_kill(fq); 277 spin_unlock(&fq->q.lock); 278 279 fq_put(fq, &work); 280 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS); 281 } 282 } 283 284 static void ip6_frag_expire(unsigned long data) 285 { 286 struct frag_queue *fq = (struct frag_queue *) data; 287 struct net_device *dev = NULL; 288 289 spin_lock(&fq->q.lock); 290 291 if (fq->q.last_in & COMPLETE) 292 goto out; 293 294 fq_kill(fq); 295 296 dev = dev_get_by_index(&init_net, fq->iif); 297 if (!dev) 298 goto out; 299 300 rcu_read_lock(); 301 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT); 302 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 303 rcu_read_unlock(); 304 305 /* Don't send error if the first segment did not arrive. */ 306 if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments) 307 goto out; 308 309 /* 310 But use as source device on which LAST ARRIVED 311 segment was received. And do not use fq->dev 312 pointer directly, device might already disappeared. 313 */ 314 fq->q.fragments->dev = dev; 315 icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev); 316 out: 317 if (dev) 318 dev_put(dev); 319 spin_unlock(&fq->q.lock); 320 fq_put(fq, NULL); 321 } 322 323 /* Creation primitives. */ 324 325 326 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in) 327 { 328 struct frag_queue *fq; 329 unsigned int hash; 330 #ifdef CONFIG_SMP 331 struct hlist_node *n; 332 #endif 333 334 write_lock(&ip6_frags.lock); 335 hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr); 336 #ifdef CONFIG_SMP 337 hlist_for_each_entry(fq, n, &ip6_frags.hash[hash], q.list) { 338 if (fq->id == fq_in->id && 339 ipv6_addr_equal(&fq_in->saddr, &fq->saddr) && 340 ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) { 341 atomic_inc(&fq->q.refcnt); 342 write_unlock(&ip6_frags.lock); 343 fq_in->q.last_in |= COMPLETE; 344 fq_put(fq_in, NULL); 345 return fq; 346 } 347 } 348 #endif 349 fq = fq_in; 350 351 if (!mod_timer(&fq->q.timer, jiffies + ip6_frags_ctl.timeout)) 352 atomic_inc(&fq->q.refcnt); 353 354 atomic_inc(&fq->q.refcnt); 355 hlist_add_head(&fq->q.list, &ip6_frags.hash[hash]); 356 INIT_LIST_HEAD(&fq->q.lru_list); 357 list_add_tail(&fq->q.lru_list, &ip6_frags.lru_list); 358 ip6_frags.nqueues++; 359 write_unlock(&ip6_frags.lock); 360 return fq; 361 } 362 363 364 static struct frag_queue * 365 ip6_frag_create(__be32 id, struct in6_addr *src, struct in6_addr *dst, 366 struct inet6_dev *idev) 367 { 368 struct frag_queue *fq; 369 370 if ((fq = frag_alloc_queue()) == NULL) 371 goto oom; 372 373 fq->id = id; 374 ipv6_addr_copy(&fq->saddr, src); 375 ipv6_addr_copy(&fq->daddr, dst); 376 377 init_timer(&fq->q.timer); 378 fq->q.timer.function = ip6_frag_expire; 379 fq->q.timer.data = (long) fq; 380 spin_lock_init(&fq->q.lock); 381 atomic_set(&fq->q.refcnt, 1); 382 383 return ip6_frag_intern(fq); 384 385 oom: 386 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS); 387 return NULL; 388 } 389 390 static __inline__ struct frag_queue * 391 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst, 392 struct inet6_dev *idev) 393 { 394 struct frag_queue *fq; 395 struct hlist_node *n; 396 unsigned int hash; 397 398 read_lock(&ip6_frags.lock); 399 hash = ip6qhashfn(id, src, dst); 400 hlist_for_each_entry(fq, n, &ip6_frags.hash[hash], q.list) { 401 if (fq->id == id && 402 ipv6_addr_equal(src, &fq->saddr) && 403 ipv6_addr_equal(dst, &fq->daddr)) { 404 atomic_inc(&fq->q.refcnt); 405 read_unlock(&ip6_frags.lock); 406 return fq; 407 } 408 } 409 read_unlock(&ip6_frags.lock); 410 411 return ip6_frag_create(id, src, dst, idev); 412 } 413 414 415 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 416 struct frag_hdr *fhdr, int nhoff) 417 { 418 struct sk_buff *prev, *next; 419 struct net_device *dev; 420 int offset, end; 421 422 if (fq->q.last_in & COMPLETE) 423 goto err; 424 425 offset = ntohs(fhdr->frag_off) & ~0x7; 426 end = offset + (ntohs(ipv6_hdr(skb)->payload_len) - 427 ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1))); 428 429 if ((unsigned int)end > IPV6_MAXPLEN) { 430 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), 431 IPSTATS_MIB_INHDRERRORS); 432 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 433 ((u8 *)&fhdr->frag_off - 434 skb_network_header(skb))); 435 return -1; 436 } 437 438 if (skb->ip_summed == CHECKSUM_COMPLETE) { 439 const unsigned char *nh = skb_network_header(skb); 440 skb->csum = csum_sub(skb->csum, 441 csum_partial(nh, (u8 *)(fhdr + 1) - nh, 442 0)); 443 } 444 445 /* Is this the final fragment? */ 446 if (!(fhdr->frag_off & htons(IP6_MF))) { 447 /* If we already have some bits beyond end 448 * or have different end, the segment is corrupted. 449 */ 450 if (end < fq->q.len || 451 ((fq->q.last_in & LAST_IN) && end != fq->q.len)) 452 goto err; 453 fq->q.last_in |= LAST_IN; 454 fq->q.len = end; 455 } else { 456 /* Check if the fragment is rounded to 8 bytes. 457 * Required by the RFC. 458 */ 459 if (end & 0x7) { 460 /* RFC2460 says always send parameter problem in 461 * this case. -DaveM 462 */ 463 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), 464 IPSTATS_MIB_INHDRERRORS); 465 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 466 offsetof(struct ipv6hdr, payload_len)); 467 return -1; 468 } 469 if (end > fq->q.len) { 470 /* Some bits beyond end -> corruption. */ 471 if (fq->q.last_in & LAST_IN) 472 goto err; 473 fq->q.len = end; 474 } 475 } 476 477 if (end == offset) 478 goto err; 479 480 /* Point into the IP datagram 'data' part. */ 481 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) 482 goto err; 483 484 if (pskb_trim_rcsum(skb, end - offset)) 485 goto err; 486 487 /* Find out which fragments are in front and at the back of us 488 * in the chain of fragments so far. We must know where to put 489 * this fragment, right? 490 */ 491 prev = NULL; 492 for(next = fq->q.fragments; next != NULL; next = next->next) { 493 if (FRAG6_CB(next)->offset >= offset) 494 break; /* bingo! */ 495 prev = next; 496 } 497 498 /* We found where to put this one. Check for overlap with 499 * preceding fragment, and, if needed, align things so that 500 * any overlaps are eliminated. 501 */ 502 if (prev) { 503 int i = (FRAG6_CB(prev)->offset + prev->len) - offset; 504 505 if (i > 0) { 506 offset += i; 507 if (end <= offset) 508 goto err; 509 if (!pskb_pull(skb, i)) 510 goto err; 511 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 512 skb->ip_summed = CHECKSUM_NONE; 513 } 514 } 515 516 /* Look for overlap with succeeding segments. 517 * If we can merge fragments, do it. 518 */ 519 while (next && FRAG6_CB(next)->offset < end) { 520 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */ 521 522 if (i < next->len) { 523 /* Eat head of the next overlapped fragment 524 * and leave the loop. The next ones cannot overlap. 525 */ 526 if (!pskb_pull(next, i)) 527 goto err; 528 FRAG6_CB(next)->offset += i; /* next fragment */ 529 fq->q.meat -= i; 530 if (next->ip_summed != CHECKSUM_UNNECESSARY) 531 next->ip_summed = CHECKSUM_NONE; 532 break; 533 } else { 534 struct sk_buff *free_it = next; 535 536 /* Old fragment is completely overridden with 537 * new one drop it. 538 */ 539 next = next->next; 540 541 if (prev) 542 prev->next = next; 543 else 544 fq->q.fragments = next; 545 546 fq->q.meat -= free_it->len; 547 frag_kfree_skb(free_it, NULL); 548 } 549 } 550 551 FRAG6_CB(skb)->offset = offset; 552 553 /* Insert this fragment in the chain of fragments. */ 554 skb->next = next; 555 if (prev) 556 prev->next = skb; 557 else 558 fq->q.fragments = skb; 559 560 dev = skb->dev; 561 if (dev) { 562 fq->iif = dev->ifindex; 563 skb->dev = NULL; 564 } 565 fq->q.stamp = skb->tstamp; 566 fq->q.meat += skb->len; 567 atomic_add(skb->truesize, &ip6_frags.mem); 568 569 /* The first fragment. 570 * nhoffset is obtained from the first fragment, of course. 571 */ 572 if (offset == 0) { 573 fq->nhoffset = nhoff; 574 fq->q.last_in |= FIRST_IN; 575 } 576 577 if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len) 578 return ip6_frag_reasm(fq, prev, dev); 579 580 write_lock(&ip6_frags.lock); 581 list_move_tail(&fq->q.lru_list, &ip6_frags.lru_list); 582 write_unlock(&ip6_frags.lock); 583 return -1; 584 585 err: 586 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS); 587 kfree_skb(skb); 588 return -1; 589 } 590 591 /* 592 * Check if this packet is complete. 593 * Returns NULL on failure by any reason, and pointer 594 * to current nexthdr field in reassembled frame. 595 * 596 * It is called with locked fq, and caller must check that 597 * queue is eligible for reassembly i.e. it is not COMPLETE, 598 * the last and the first frames arrived and all the bits are here. 599 */ 600 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 601 struct net_device *dev) 602 { 603 struct sk_buff *fp, *head = fq->q.fragments; 604 int payload_len; 605 unsigned int nhoff; 606 607 fq_kill(fq); 608 609 /* Make the one we just received the head. */ 610 if (prev) { 611 head = prev->next; 612 fp = skb_clone(head, GFP_ATOMIC); 613 614 if (!fp) 615 goto out_oom; 616 617 fp->next = head->next; 618 prev->next = fp; 619 620 skb_morph(head, fq->q.fragments); 621 head->next = fq->q.fragments->next; 622 623 kfree_skb(fq->q.fragments); 624 fq->q.fragments = head; 625 } 626 627 BUG_TRAP(head != NULL); 628 BUG_TRAP(FRAG6_CB(head)->offset == 0); 629 630 /* Unfragmented part is taken from the first segment. */ 631 payload_len = ((head->data - skb_network_header(head)) - 632 sizeof(struct ipv6hdr) + fq->q.len - 633 sizeof(struct frag_hdr)); 634 if (payload_len > IPV6_MAXPLEN) 635 goto out_oversize; 636 637 /* Head of list must not be cloned. */ 638 if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) 639 goto out_oom; 640 641 /* If the first fragment is fragmented itself, we split 642 * it to two chunks: the first with data and paged part 643 * and the second, holding only fragments. */ 644 if (skb_shinfo(head)->frag_list) { 645 struct sk_buff *clone; 646 int i, plen = 0; 647 648 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 649 goto out_oom; 650 clone->next = head->next; 651 head->next = clone; 652 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 653 skb_shinfo(head)->frag_list = NULL; 654 for (i=0; i<skb_shinfo(head)->nr_frags; i++) 655 plen += skb_shinfo(head)->frags[i].size; 656 clone->len = clone->data_len = head->data_len - plen; 657 head->data_len -= clone->len; 658 head->len -= clone->len; 659 clone->csum = 0; 660 clone->ip_summed = head->ip_summed; 661 atomic_add(clone->truesize, &ip6_frags.mem); 662 } 663 664 /* We have to remove fragment header from datagram and to relocate 665 * header in order to calculate ICV correctly. */ 666 nhoff = fq->nhoffset; 667 skb_network_header(head)[nhoff] = skb_transport_header(head)[0]; 668 memmove(head->head + sizeof(struct frag_hdr), head->head, 669 (head->data - head->head) - sizeof(struct frag_hdr)); 670 head->mac_header += sizeof(struct frag_hdr); 671 head->network_header += sizeof(struct frag_hdr); 672 673 skb_shinfo(head)->frag_list = head->next; 674 skb_reset_transport_header(head); 675 skb_push(head, head->data - skb_network_header(head)); 676 atomic_sub(head->truesize, &ip6_frags.mem); 677 678 for (fp=head->next; fp; fp = fp->next) { 679 head->data_len += fp->len; 680 head->len += fp->len; 681 if (head->ip_summed != fp->ip_summed) 682 head->ip_summed = CHECKSUM_NONE; 683 else if (head->ip_summed == CHECKSUM_COMPLETE) 684 head->csum = csum_add(head->csum, fp->csum); 685 head->truesize += fp->truesize; 686 atomic_sub(fp->truesize, &ip6_frags.mem); 687 } 688 689 head->next = NULL; 690 head->dev = dev; 691 head->tstamp = fq->q.stamp; 692 ipv6_hdr(head)->payload_len = htons(payload_len); 693 IP6CB(head)->nhoff = nhoff; 694 695 /* Yes, and fold redundant checksum back. 8) */ 696 if (head->ip_summed == CHECKSUM_COMPLETE) 697 head->csum = csum_partial(skb_network_header(head), 698 skb_network_header_len(head), 699 head->csum); 700 701 rcu_read_lock(); 702 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS); 703 rcu_read_unlock(); 704 fq->q.fragments = NULL; 705 return 1; 706 707 out_oversize: 708 if (net_ratelimit()) 709 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len); 710 goto out_fail; 711 out_oom: 712 if (net_ratelimit()) 713 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n"); 714 out_fail: 715 rcu_read_lock(); 716 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 717 rcu_read_unlock(); 718 return -1; 719 } 720 721 static int ipv6_frag_rcv(struct sk_buff **skbp) 722 { 723 struct sk_buff *skb = *skbp; 724 struct frag_hdr *fhdr; 725 struct frag_queue *fq; 726 struct ipv6hdr *hdr = ipv6_hdr(skb); 727 728 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS); 729 730 /* Jumbo payload inhibits frag. header */ 731 if (hdr->payload_len==0) { 732 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); 733 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 734 skb_network_header_len(skb)); 735 return -1; 736 } 737 if (!pskb_may_pull(skb, (skb_transport_offset(skb) + 738 sizeof(struct frag_hdr)))) { 739 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); 740 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 741 skb_network_header_len(skb)); 742 return -1; 743 } 744 745 hdr = ipv6_hdr(skb); 746 fhdr = (struct frag_hdr *)skb_transport_header(skb); 747 748 if (!(fhdr->frag_off & htons(0xFFF9))) { 749 /* It is not a fragmented frame */ 750 skb->transport_header += sizeof(struct frag_hdr); 751 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS); 752 753 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb); 754 return 1; 755 } 756 757 if (atomic_read(&ip6_frags.mem) > ip6_frags_ctl.high_thresh) 758 ip6_evictor(ip6_dst_idev(skb->dst)); 759 760 if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr, 761 ip6_dst_idev(skb->dst))) != NULL) { 762 int ret; 763 764 spin_lock(&fq->q.lock); 765 766 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); 767 768 spin_unlock(&fq->q.lock); 769 fq_put(fq, NULL); 770 return ret; 771 } 772 773 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS); 774 kfree_skb(skb); 775 return -1; 776 } 777 778 static struct inet6_protocol frag_protocol = 779 { 780 .handler = ipv6_frag_rcv, 781 .flags = INET6_PROTO_NOPOLICY, 782 }; 783 784 void __init ipv6_frag_init(void) 785 { 786 if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0) 787 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n"); 788 789 init_timer(&ip6_frags.secret_timer); 790 ip6_frags.secret_timer.function = ip6_frag_secret_rebuild; 791 ip6_frags.secret_timer.expires = jiffies + ip6_frags_ctl.secret_interval; 792 add_timer(&ip6_frags.secret_timer); 793 794 ip6_frags.ctl = &ip6_frags_ctl; 795 inet_frags_init(&ip6_frags); 796 } 797