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