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 46 #include <net/sock.h> 47 #include <net/snmp.h> 48 49 #include <net/ipv6.h> 50 #include <net/protocol.h> 51 #include <net/transp_v6.h> 52 #include <net/rawv6.h> 53 #include <net/ndisc.h> 54 #include <net/addrconf.h> 55 56 int sysctl_ip6frag_high_thresh = 256*1024; 57 int sysctl_ip6frag_low_thresh = 192*1024; 58 59 int sysctl_ip6frag_time = IPV6_FRAG_TIMEOUT; 60 61 struct ip6frag_skb_cb 62 { 63 struct inet6_skb_parm h; 64 int offset; 65 }; 66 67 #define FRAG6_CB(skb) ((struct ip6frag_skb_cb*)((skb)->cb)) 68 69 70 /* 71 * Equivalent of ipv4 struct ipq 72 */ 73 74 struct frag_queue 75 { 76 struct hlist_node list; 77 struct list_head lru_list; /* lru list member */ 78 79 __u32 id; /* fragment id */ 80 struct in6_addr saddr; 81 struct in6_addr daddr; 82 83 spinlock_t lock; 84 atomic_t refcnt; 85 struct timer_list timer; /* expire timer */ 86 struct sk_buff *fragments; 87 int len; 88 int meat; 89 int iif; 90 struct timeval stamp; 91 unsigned int csum; 92 __u8 last_in; /* has first/last segment arrived? */ 93 #define COMPLETE 4 94 #define FIRST_IN 2 95 #define LAST_IN 1 96 __u16 nhoffset; 97 }; 98 99 /* Hash table. */ 100 101 #define IP6Q_HASHSZ 64 102 103 static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ]; 104 static DEFINE_RWLOCK(ip6_frag_lock); 105 static u32 ip6_frag_hash_rnd; 106 static LIST_HEAD(ip6_frag_lru_list); 107 int ip6_frag_nqueues = 0; 108 109 static __inline__ void __fq_unlink(struct frag_queue *fq) 110 { 111 hlist_del(&fq->list); 112 list_del(&fq->lru_list); 113 ip6_frag_nqueues--; 114 } 115 116 static __inline__ void fq_unlink(struct frag_queue *fq) 117 { 118 write_lock(&ip6_frag_lock); 119 __fq_unlink(fq); 120 write_unlock(&ip6_frag_lock); 121 } 122 123 /* 124 * callers should be careful not to use the hash value outside the ipfrag_lock 125 * as doing so could race with ipfrag_hash_rnd being recalculated. 126 */ 127 static unsigned int ip6qhashfn(u32 id, struct in6_addr *saddr, 128 struct in6_addr *daddr) 129 { 130 u32 a, b, c; 131 132 a = saddr->s6_addr32[0]; 133 b = saddr->s6_addr32[1]; 134 c = saddr->s6_addr32[2]; 135 136 a += JHASH_GOLDEN_RATIO; 137 b += JHASH_GOLDEN_RATIO; 138 c += ip6_frag_hash_rnd; 139 __jhash_mix(a, b, c); 140 141 a += saddr->s6_addr32[3]; 142 b += daddr->s6_addr32[0]; 143 c += daddr->s6_addr32[1]; 144 __jhash_mix(a, b, c); 145 146 a += daddr->s6_addr32[2]; 147 b += daddr->s6_addr32[3]; 148 c += id; 149 __jhash_mix(a, b, c); 150 151 return c & (IP6Q_HASHSZ - 1); 152 } 153 154 static struct timer_list ip6_frag_secret_timer; 155 int sysctl_ip6frag_secret_interval = 10 * 60 * HZ; 156 157 static void ip6_frag_secret_rebuild(unsigned long dummy) 158 { 159 unsigned long now = jiffies; 160 int i; 161 162 write_lock(&ip6_frag_lock); 163 get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32)); 164 for (i = 0; i < IP6Q_HASHSZ; i++) { 165 struct frag_queue *q; 166 struct hlist_node *p, *n; 167 168 hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) { 169 unsigned int hval = ip6qhashfn(q->id, 170 &q->saddr, 171 &q->daddr); 172 173 if (hval != i) { 174 hlist_del(&q->list); 175 176 /* Relink to new hash chain. */ 177 hlist_add_head(&q->list, 178 &ip6_frag_hash[hval]); 179 180 } 181 } 182 } 183 write_unlock(&ip6_frag_lock); 184 185 mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval); 186 } 187 188 atomic_t ip6_frag_mem = ATOMIC_INIT(0); 189 190 /* Memory Tracking Functions. */ 191 static inline void frag_kfree_skb(struct sk_buff *skb, int *work) 192 { 193 if (work) 194 *work -= skb->truesize; 195 atomic_sub(skb->truesize, &ip6_frag_mem); 196 kfree_skb(skb); 197 } 198 199 static inline void frag_free_queue(struct frag_queue *fq, int *work) 200 { 201 if (work) 202 *work -= sizeof(struct frag_queue); 203 atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem); 204 kfree(fq); 205 } 206 207 static inline struct frag_queue *frag_alloc_queue(void) 208 { 209 struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC); 210 211 if(!fq) 212 return NULL; 213 atomic_add(sizeof(struct frag_queue), &ip6_frag_mem); 214 return fq; 215 } 216 217 /* Destruction primitives. */ 218 219 /* Complete destruction of fq. */ 220 static void ip6_frag_destroy(struct frag_queue *fq, int *work) 221 { 222 struct sk_buff *fp; 223 224 BUG_TRAP(fq->last_in&COMPLETE); 225 BUG_TRAP(del_timer(&fq->timer) == 0); 226 227 /* Release all fragment data. */ 228 fp = fq->fragments; 229 while (fp) { 230 struct sk_buff *xp = fp->next; 231 232 frag_kfree_skb(fp, work); 233 fp = xp; 234 } 235 236 frag_free_queue(fq, work); 237 } 238 239 static __inline__ void fq_put(struct frag_queue *fq, int *work) 240 { 241 if (atomic_dec_and_test(&fq->refcnt)) 242 ip6_frag_destroy(fq, work); 243 } 244 245 /* Kill fq entry. It is not destroyed immediately, 246 * because caller (and someone more) holds reference count. 247 */ 248 static __inline__ void fq_kill(struct frag_queue *fq) 249 { 250 if (del_timer(&fq->timer)) 251 atomic_dec(&fq->refcnt); 252 253 if (!(fq->last_in & COMPLETE)) { 254 fq_unlink(fq); 255 atomic_dec(&fq->refcnt); 256 fq->last_in |= COMPLETE; 257 } 258 } 259 260 static void ip6_evictor(void) 261 { 262 struct frag_queue *fq; 263 struct list_head *tmp; 264 int work; 265 266 work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh; 267 if (work <= 0) 268 return; 269 270 while(work > 0) { 271 read_lock(&ip6_frag_lock); 272 if (list_empty(&ip6_frag_lru_list)) { 273 read_unlock(&ip6_frag_lock); 274 return; 275 } 276 tmp = ip6_frag_lru_list.next; 277 fq = list_entry(tmp, struct frag_queue, lru_list); 278 atomic_inc(&fq->refcnt); 279 read_unlock(&ip6_frag_lock); 280 281 spin_lock(&fq->lock); 282 if (!(fq->last_in&COMPLETE)) 283 fq_kill(fq); 284 spin_unlock(&fq->lock); 285 286 fq_put(fq, &work); 287 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 288 } 289 } 290 291 static void ip6_frag_expire(unsigned long data) 292 { 293 struct frag_queue *fq = (struct frag_queue *) data; 294 struct net_device *dev; 295 296 spin_lock(&fq->lock); 297 298 if (fq->last_in & COMPLETE) 299 goto out; 300 301 fq_kill(fq); 302 303 IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT); 304 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 305 306 /* Don't send error if the first segment did not arrive. */ 307 if (!(fq->last_in&FIRST_IN) || !fq->fragments) 308 goto out; 309 310 dev = dev_get_by_index(fq->iif); 311 if (!dev) 312 goto out; 313 314 /* 315 But use as source device on which LAST ARRIVED 316 segment was received. And do not use fq->dev 317 pointer directly, device might already disappeared. 318 */ 319 fq->fragments->dev = dev; 320 icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev); 321 dev_put(dev); 322 out: 323 spin_unlock(&fq->lock); 324 fq_put(fq, NULL); 325 } 326 327 /* Creation primitives. */ 328 329 330 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in) 331 { 332 struct frag_queue *fq; 333 unsigned int hash; 334 #ifdef CONFIG_SMP 335 struct hlist_node *n; 336 #endif 337 338 write_lock(&ip6_frag_lock); 339 hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr); 340 #ifdef CONFIG_SMP 341 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { 342 if (fq->id == fq_in->id && 343 ipv6_addr_equal(&fq_in->saddr, &fq->saddr) && 344 ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) { 345 atomic_inc(&fq->refcnt); 346 write_unlock(&ip6_frag_lock); 347 fq_in->last_in |= COMPLETE; 348 fq_put(fq_in, NULL); 349 return fq; 350 } 351 } 352 #endif 353 fq = fq_in; 354 355 if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time)) 356 atomic_inc(&fq->refcnt); 357 358 atomic_inc(&fq->refcnt); 359 hlist_add_head(&fq->list, &ip6_frag_hash[hash]); 360 INIT_LIST_HEAD(&fq->lru_list); 361 list_add_tail(&fq->lru_list, &ip6_frag_lru_list); 362 ip6_frag_nqueues++; 363 write_unlock(&ip6_frag_lock); 364 return fq; 365 } 366 367 368 static struct frag_queue * 369 ip6_frag_create(u32 id, struct in6_addr *src, struct in6_addr *dst) 370 { 371 struct frag_queue *fq; 372 373 if ((fq = frag_alloc_queue()) == NULL) 374 goto oom; 375 376 fq->id = id; 377 ipv6_addr_copy(&fq->saddr, src); 378 ipv6_addr_copy(&fq->daddr, dst); 379 380 init_timer(&fq->timer); 381 fq->timer.function = ip6_frag_expire; 382 fq->timer.data = (long) fq; 383 spin_lock_init(&fq->lock); 384 atomic_set(&fq->refcnt, 1); 385 386 return ip6_frag_intern(fq); 387 388 oom: 389 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 390 return NULL; 391 } 392 393 static __inline__ struct frag_queue * 394 fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst) 395 { 396 struct frag_queue *fq; 397 struct hlist_node *n; 398 unsigned int hash; 399 400 read_lock(&ip6_frag_lock); 401 hash = ip6qhashfn(id, src, dst); 402 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { 403 if (fq->id == id && 404 ipv6_addr_equal(src, &fq->saddr) && 405 ipv6_addr_equal(dst, &fq->daddr)) { 406 atomic_inc(&fq->refcnt); 407 read_unlock(&ip6_frag_lock); 408 return fq; 409 } 410 } 411 read_unlock(&ip6_frag_lock); 412 413 return ip6_frag_create(id, src, dst); 414 } 415 416 417 static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 418 struct frag_hdr *fhdr, int nhoff) 419 { 420 struct sk_buff *prev, *next; 421 int offset, end; 422 423 if (fq->last_in & COMPLETE) 424 goto err; 425 426 offset = ntohs(fhdr->frag_off) & ~0x7; 427 end = offset + (ntohs(skb->nh.ipv6h->payload_len) - 428 ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1))); 429 430 if ((unsigned int)end > IPV6_MAXPLEN) { 431 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 432 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw); 433 return; 434 } 435 436 if (skb->ip_summed == CHECKSUM_HW) 437 skb->csum = csum_sub(skb->csum, 438 csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0)); 439 440 /* Is this the final fragment? */ 441 if (!(fhdr->frag_off & htons(IP6_MF))) { 442 /* If we already have some bits beyond end 443 * or have different end, the segment is corrupted. 444 */ 445 if (end < fq->len || 446 ((fq->last_in & LAST_IN) && end != fq->len)) 447 goto err; 448 fq->last_in |= LAST_IN; 449 fq->len = end; 450 } else { 451 /* Check if the fragment is rounded to 8 bytes. 452 * Required by the RFC. 453 */ 454 if (end & 0x7) { 455 /* RFC2460 says always send parameter problem in 456 * this case. -DaveM 457 */ 458 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 459 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 460 offsetof(struct ipv6hdr, payload_len)); 461 return; 462 } 463 if (end > fq->len) { 464 /* Some bits beyond end -> corruption. */ 465 if (fq->last_in & LAST_IN) 466 goto err; 467 fq->len = end; 468 } 469 } 470 471 if (end == offset) 472 goto err; 473 474 /* Point into the IP datagram 'data' part. */ 475 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) 476 goto err; 477 478 if (pskb_trim_rcsum(skb, end - offset)) 479 goto err; 480 481 /* Find out which fragments are in front and at the back of us 482 * in the chain of fragments so far. We must know where to put 483 * this fragment, right? 484 */ 485 prev = NULL; 486 for(next = fq->fragments; next != NULL; next = next->next) { 487 if (FRAG6_CB(next)->offset >= offset) 488 break; /* bingo! */ 489 prev = next; 490 } 491 492 /* We found where to put this one. Check for overlap with 493 * preceding fragment, and, if needed, align things so that 494 * any overlaps are eliminated. 495 */ 496 if (prev) { 497 int i = (FRAG6_CB(prev)->offset + prev->len) - offset; 498 499 if (i > 0) { 500 offset += i; 501 if (end <= offset) 502 goto err; 503 if (!pskb_pull(skb, i)) 504 goto err; 505 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 506 skb->ip_summed = CHECKSUM_NONE; 507 } 508 } 509 510 /* Look for overlap with succeeding segments. 511 * If we can merge fragments, do it. 512 */ 513 while (next && FRAG6_CB(next)->offset < end) { 514 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */ 515 516 if (i < next->len) { 517 /* Eat head of the next overlapped fragment 518 * and leave the loop. The next ones cannot overlap. 519 */ 520 if (!pskb_pull(next, i)) 521 goto err; 522 FRAG6_CB(next)->offset += i; /* next fragment */ 523 fq->meat -= i; 524 if (next->ip_summed != CHECKSUM_UNNECESSARY) 525 next->ip_summed = CHECKSUM_NONE; 526 break; 527 } else { 528 struct sk_buff *free_it = next; 529 530 /* Old fragment is completely overridden with 531 * new one drop it. 532 */ 533 next = next->next; 534 535 if (prev) 536 prev->next = next; 537 else 538 fq->fragments = next; 539 540 fq->meat -= free_it->len; 541 frag_kfree_skb(free_it, NULL); 542 } 543 } 544 545 FRAG6_CB(skb)->offset = offset; 546 547 /* Insert this fragment in the chain of fragments. */ 548 skb->next = next; 549 if (prev) 550 prev->next = skb; 551 else 552 fq->fragments = skb; 553 554 if (skb->dev) 555 fq->iif = skb->dev->ifindex; 556 skb->dev = NULL; 557 skb_get_timestamp(skb, &fq->stamp); 558 fq->meat += skb->len; 559 atomic_add(skb->truesize, &ip6_frag_mem); 560 561 /* The first fragment. 562 * nhoffset is obtained from the first fragment, of course. 563 */ 564 if (offset == 0) { 565 fq->nhoffset = nhoff; 566 fq->last_in |= FIRST_IN; 567 } 568 write_lock(&ip6_frag_lock); 569 list_move_tail(&fq->lru_list, &ip6_frag_lru_list); 570 write_unlock(&ip6_frag_lock); 571 return; 572 573 err: 574 IP6_INC_STATS(IPSTATS_MIB_REASMFAILS); 575 kfree_skb(skb); 576 } 577 578 /* 579 * Check if this packet is complete. 580 * Returns NULL on failure by any reason, and pointer 581 * to current nexthdr field in reassembled frame. 582 * 583 * It is called with locked fq, and caller must check that 584 * queue is eligible for reassembly i.e. it is not COMPLETE, 585 * the last and the first frames arrived and all the bits are here. 586 */ 587 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in, 588 struct net_device *dev) 589 { 590 struct sk_buff *fp, *head = fq->fragments; 591 int payload_len; 592 unsigned int nhoff; 593 594 fq_kill(fq); 595 596 BUG_TRAP(head != NULL); 597 BUG_TRAP(FRAG6_CB(head)->offset == 0); 598 599 /* Unfragmented part is taken from the first segment. */ 600 payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr); 601 if (payload_len > IPV6_MAXPLEN) 602 goto out_oversize; 603 604 /* Head of list must not be cloned. */ 605 if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) 606 goto out_oom; 607 608 /* If the first fragment is fragmented itself, we split 609 * it to two chunks: the first with data and paged part 610 * and the second, holding only fragments. */ 611 if (skb_shinfo(head)->frag_list) { 612 struct sk_buff *clone; 613 int i, plen = 0; 614 615 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 616 goto out_oom; 617 clone->next = head->next; 618 head->next = clone; 619 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 620 skb_shinfo(head)->frag_list = NULL; 621 for (i=0; i<skb_shinfo(head)->nr_frags; i++) 622 plen += skb_shinfo(head)->frags[i].size; 623 clone->len = clone->data_len = head->data_len - plen; 624 head->data_len -= clone->len; 625 head->len -= clone->len; 626 clone->csum = 0; 627 clone->ip_summed = head->ip_summed; 628 atomic_add(clone->truesize, &ip6_frag_mem); 629 } 630 631 /* We have to remove fragment header from datagram and to relocate 632 * header in order to calculate ICV correctly. */ 633 nhoff = fq->nhoffset; 634 head->nh.raw[nhoff] = head->h.raw[0]; 635 memmove(head->head + sizeof(struct frag_hdr), head->head, 636 (head->data - head->head) - sizeof(struct frag_hdr)); 637 head->mac.raw += sizeof(struct frag_hdr); 638 head->nh.raw += sizeof(struct frag_hdr); 639 640 skb_shinfo(head)->frag_list = head->next; 641 head->h.raw = head->data; 642 skb_push(head, head->data - head->nh.raw); 643 atomic_sub(head->truesize, &ip6_frag_mem); 644 645 for (fp=head->next; fp; fp = fp->next) { 646 head->data_len += fp->len; 647 head->len += fp->len; 648 if (head->ip_summed != fp->ip_summed) 649 head->ip_summed = CHECKSUM_NONE; 650 else if (head->ip_summed == CHECKSUM_HW) 651 head->csum = csum_add(head->csum, fp->csum); 652 head->truesize += fp->truesize; 653 atomic_sub(fp->truesize, &ip6_frag_mem); 654 } 655 656 head->next = NULL; 657 head->dev = dev; 658 skb_set_timestamp(head, &fq->stamp); 659 head->nh.ipv6h->payload_len = htons(payload_len); 660 IP6CB(head)->nhoff = nhoff; 661 662 *skb_in = head; 663 664 /* Yes, and fold redundant checksum back. 8) */ 665 if (head->ip_summed == CHECKSUM_HW) 666 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum); 667 668 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS); 669 fq->fragments = NULL; 670 return 1; 671 672 out_oversize: 673 if (net_ratelimit()) 674 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len); 675 goto out_fail; 676 out_oom: 677 if (net_ratelimit()) 678 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n"); 679 out_fail: 680 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 681 return -1; 682 } 683 684 static int ipv6_frag_rcv(struct sk_buff **skbp) 685 { 686 struct sk_buff *skb = *skbp; 687 struct net_device *dev = skb->dev; 688 struct frag_hdr *fhdr; 689 struct frag_queue *fq; 690 struct ipv6hdr *hdr; 691 692 hdr = skb->nh.ipv6h; 693 694 IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS); 695 696 /* Jumbo payload inhibits frag. header */ 697 if (hdr->payload_len==0) { 698 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS); 699 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw); 700 return -1; 701 } 702 if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) { 703 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS); 704 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw); 705 return -1; 706 } 707 708 hdr = skb->nh.ipv6h; 709 fhdr = (struct frag_hdr *)skb->h.raw; 710 711 if (!(fhdr->frag_off & htons(0xFFF9))) { 712 /* It is not a fragmented frame */ 713 skb->h.raw += sizeof(struct frag_hdr); 714 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS); 715 716 IP6CB(skb)->nhoff = (u8*)fhdr - skb->nh.raw; 717 return 1; 718 } 719 720 if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh) 721 ip6_evictor(); 722 723 if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) { 724 int ret = -1; 725 726 spin_lock(&fq->lock); 727 728 ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); 729 730 if (fq->last_in == (FIRST_IN|LAST_IN) && 731 fq->meat == fq->len) 732 ret = ip6_frag_reasm(fq, skbp, dev); 733 734 spin_unlock(&fq->lock); 735 fq_put(fq, NULL); 736 return ret; 737 } 738 739 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 740 kfree_skb(skb); 741 return -1; 742 } 743 744 static struct inet6_protocol frag_protocol = 745 { 746 .handler = ipv6_frag_rcv, 747 .flags = INET6_PROTO_NOPOLICY, 748 }; 749 750 void __init ipv6_frag_init(void) 751 { 752 if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0) 753 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n"); 754 755 ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^ 756 (jiffies ^ (jiffies >> 6))); 757 758 init_timer(&ip6_frag_secret_timer); 759 ip6_frag_secret_timer.function = ip6_frag_secret_rebuild; 760 ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval; 761 add_timer(&ip6_frag_secret_timer); 762 } 763