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