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 frag_queue *next; 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 struct frag_queue **pprev; 99 }; 100 101 /* Hash table. */ 102 103 #define IP6Q_HASHSZ 64 104 105 static struct frag_queue *ip6_frag_hash[IP6Q_HASHSZ]; 106 static DEFINE_RWLOCK(ip6_frag_lock); 107 static u32 ip6_frag_hash_rnd; 108 static LIST_HEAD(ip6_frag_lru_list); 109 int ip6_frag_nqueues = 0; 110 111 static __inline__ void __fq_unlink(struct frag_queue *fq) 112 { 113 if(fq->next) 114 fq->next->pprev = fq->pprev; 115 *fq->pprev = fq->next; 116 list_del(&fq->lru_list); 117 ip6_frag_nqueues--; 118 } 119 120 static __inline__ void fq_unlink(struct frag_queue *fq) 121 { 122 write_lock(&ip6_frag_lock); 123 __fq_unlink(fq); 124 write_unlock(&ip6_frag_lock); 125 } 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; 166 167 q = ip6_frag_hash[i]; 168 while (q) { 169 struct frag_queue *next = q->next; 170 unsigned int hval = ip6qhashfn(q->id, 171 &q->saddr, 172 &q->daddr); 173 174 if (hval != i) { 175 /* Unlink. */ 176 if (q->next) 177 q->next->pprev = q->pprev; 178 *q->pprev = q->next; 179 180 /* Relink to new hash chain. */ 181 if ((q->next = ip6_frag_hash[hval]) != NULL) 182 q->next->pprev = &q->next; 183 ip6_frag_hash[hval] = q; 184 q->pprev = &ip6_frag_hash[hval]; 185 } 186 187 q = next; 188 } 189 } 190 write_unlock(&ip6_frag_lock); 191 192 mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval); 193 } 194 195 atomic_t ip6_frag_mem = ATOMIC_INIT(0); 196 197 /* Memory Tracking Functions. */ 198 static inline void frag_kfree_skb(struct sk_buff *skb, int *work) 199 { 200 if (work) 201 *work -= skb->truesize; 202 atomic_sub(skb->truesize, &ip6_frag_mem); 203 kfree_skb(skb); 204 } 205 206 static inline void frag_free_queue(struct frag_queue *fq, int *work) 207 { 208 if (work) 209 *work -= sizeof(struct frag_queue); 210 atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem); 211 kfree(fq); 212 } 213 214 static inline struct frag_queue *frag_alloc_queue(void) 215 { 216 struct frag_queue *fq = kmalloc(sizeof(struct frag_queue), GFP_ATOMIC); 217 218 if(!fq) 219 return NULL; 220 atomic_add(sizeof(struct frag_queue), &ip6_frag_mem); 221 return fq; 222 } 223 224 /* Destruction primitives. */ 225 226 /* Complete destruction of fq. */ 227 static void ip6_frag_destroy(struct frag_queue *fq, int *work) 228 { 229 struct sk_buff *fp; 230 231 BUG_TRAP(fq->last_in&COMPLETE); 232 BUG_TRAP(del_timer(&fq->timer) == 0); 233 234 /* Release all fragment data. */ 235 fp = fq->fragments; 236 while (fp) { 237 struct sk_buff *xp = fp->next; 238 239 frag_kfree_skb(fp, work); 240 fp = xp; 241 } 242 243 frag_free_queue(fq, work); 244 } 245 246 static __inline__ void fq_put(struct frag_queue *fq, int *work) 247 { 248 if (atomic_dec_and_test(&fq->refcnt)) 249 ip6_frag_destroy(fq, work); 250 } 251 252 /* Kill fq entry. It is not destroyed immediately, 253 * because caller (and someone more) holds reference count. 254 */ 255 static __inline__ void fq_kill(struct frag_queue *fq) 256 { 257 if (del_timer(&fq->timer)) 258 atomic_dec(&fq->refcnt); 259 260 if (!(fq->last_in & COMPLETE)) { 261 fq_unlink(fq); 262 atomic_dec(&fq->refcnt); 263 fq->last_in |= COMPLETE; 264 } 265 } 266 267 static void ip6_evictor(void) 268 { 269 struct frag_queue *fq; 270 struct list_head *tmp; 271 int work; 272 273 work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh; 274 if (work <= 0) 275 return; 276 277 while(work > 0) { 278 read_lock(&ip6_frag_lock); 279 if (list_empty(&ip6_frag_lru_list)) { 280 read_unlock(&ip6_frag_lock); 281 return; 282 } 283 tmp = ip6_frag_lru_list.next; 284 fq = list_entry(tmp, struct frag_queue, lru_list); 285 atomic_inc(&fq->refcnt); 286 read_unlock(&ip6_frag_lock); 287 288 spin_lock(&fq->lock); 289 if (!(fq->last_in&COMPLETE)) 290 fq_kill(fq); 291 spin_unlock(&fq->lock); 292 293 fq_put(fq, &work); 294 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 295 } 296 } 297 298 static void ip6_frag_expire(unsigned long data) 299 { 300 struct frag_queue *fq = (struct frag_queue *) data; 301 302 spin_lock(&fq->lock); 303 304 if (fq->last_in & COMPLETE) 305 goto out; 306 307 fq_kill(fq); 308 309 IP6_INC_STATS_BH(IPSTATS_MIB_REASMTIMEOUT); 310 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 311 312 /* Send error only if the first segment arrived. */ 313 if (fq->last_in&FIRST_IN && fq->fragments) { 314 struct net_device *dev = dev_get_by_index(fq->iif); 315 316 /* 317 But use as source device on which LAST ARRIVED 318 segment was received. And do not use fq->dev 319 pointer directly, device might already disappeared. 320 */ 321 if (dev) { 322 fq->fragments->dev = dev; 323 icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, 324 dev); 325 dev_put(dev); 326 } 327 } 328 out: 329 spin_unlock(&fq->lock); 330 fq_put(fq, NULL); 331 } 332 333 /* Creation primitives. */ 334 335 336 static struct frag_queue *ip6_frag_intern(unsigned int hash, 337 struct frag_queue *fq_in) 338 { 339 struct frag_queue *fq; 340 341 write_lock(&ip6_frag_lock); 342 #ifdef CONFIG_SMP 343 for (fq = ip6_frag_hash[hash]; fq; fq = fq->next) { 344 if (fq->id == fq_in->id && 345 ipv6_addr_equal(&fq_in->saddr, &fq->saddr) && 346 ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) { 347 atomic_inc(&fq->refcnt); 348 write_unlock(&ip6_frag_lock); 349 fq_in->last_in |= COMPLETE; 350 fq_put(fq_in, NULL); 351 return fq; 352 } 353 } 354 #endif 355 fq = fq_in; 356 357 if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time)) 358 atomic_inc(&fq->refcnt); 359 360 atomic_inc(&fq->refcnt); 361 if((fq->next = ip6_frag_hash[hash]) != NULL) 362 fq->next->pprev = &fq->next; 363 ip6_frag_hash[hash] = fq; 364 fq->pprev = &ip6_frag_hash[hash]; 365 INIT_LIST_HEAD(&fq->lru_list); 366 list_add_tail(&fq->lru_list, &ip6_frag_lru_list); 367 ip6_frag_nqueues++; 368 write_unlock(&ip6_frag_lock); 369 return fq; 370 } 371 372 373 static struct frag_queue * 374 ip6_frag_create(unsigned int hash, u32 id, struct in6_addr *src, struct in6_addr *dst) 375 { 376 struct frag_queue *fq; 377 378 if ((fq = frag_alloc_queue()) == NULL) 379 goto oom; 380 381 memset(fq, 0, sizeof(struct frag_queue)); 382 383 fq->id = id; 384 ipv6_addr_copy(&fq->saddr, src); 385 ipv6_addr_copy(&fq->daddr, dst); 386 387 init_timer(&fq->timer); 388 fq->timer.function = ip6_frag_expire; 389 fq->timer.data = (long) fq; 390 spin_lock_init(&fq->lock); 391 atomic_set(&fq->refcnt, 1); 392 393 return ip6_frag_intern(hash, fq); 394 395 oom: 396 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 397 return NULL; 398 } 399 400 static __inline__ struct frag_queue * 401 fq_find(u32 id, struct in6_addr *src, struct in6_addr *dst) 402 { 403 struct frag_queue *fq; 404 unsigned int hash = ip6qhashfn(id, src, dst); 405 406 read_lock(&ip6_frag_lock); 407 for(fq = ip6_frag_hash[hash]; fq; fq = fq->next) { 408 if (fq->id == id && 409 ipv6_addr_equal(src, &fq->saddr) && 410 ipv6_addr_equal(dst, &fq->daddr)) { 411 atomic_inc(&fq->refcnt); 412 read_unlock(&ip6_frag_lock); 413 return fq; 414 } 415 } 416 read_unlock(&ip6_frag_lock); 417 418 return ip6_frag_create(hash, id, src, dst); 419 } 420 421 422 static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 423 struct frag_hdr *fhdr, int nhoff) 424 { 425 struct sk_buff *prev, *next; 426 int offset, end; 427 428 if (fq->last_in & COMPLETE) 429 goto err; 430 431 offset = ntohs(fhdr->frag_off) & ~0x7; 432 end = offset + (ntohs(skb->nh.ipv6h->payload_len) - 433 ((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1))); 434 435 if ((unsigned int)end > IPV6_MAXPLEN) { 436 IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS); 437 icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw); 438 return; 439 } 440 441 if (skb->ip_summed == CHECKSUM_HW) 442 skb->csum = csum_sub(skb->csum, 443 csum_partial(skb->nh.raw, (u8*)(fhdr+1)-skb->nh.raw, 0)); 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->len || 451 ((fq->last_in & LAST_IN) && end != fq->len)) 452 goto err; 453 fq->last_in |= LAST_IN; 454 fq->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(IPSTATS_MIB_INHDRERRORS); 464 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 465 offsetof(struct ipv6hdr, payload_len)); 466 return; 467 } 468 if (end > fq->len) { 469 /* Some bits beyond end -> corruption. */ 470 if (fq->last_in & LAST_IN) 471 goto err; 472 fq->len = end; 473 } 474 } 475 476 if (end == offset) 477 goto err; 478 479 /* Point into the IP datagram 'data' part. */ 480 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) 481 goto err; 482 483 if (pskb_trim_rcsum(skb, end - offset)) 484 goto err; 485 486 /* Find out which fragments are in front and at the back of us 487 * in the chain of fragments so far. We must know where to put 488 * this fragment, right? 489 */ 490 prev = NULL; 491 for(next = fq->fragments; next != NULL; next = next->next) { 492 if (FRAG6_CB(next)->offset >= offset) 493 break; /* bingo! */ 494 prev = next; 495 } 496 497 /* We found where to put this one. Check for overlap with 498 * preceding fragment, and, if needed, align things so that 499 * any overlaps are eliminated. 500 */ 501 if (prev) { 502 int i = (FRAG6_CB(prev)->offset + prev->len) - offset; 503 504 if (i > 0) { 505 offset += i; 506 if (end <= offset) 507 goto err; 508 if (!pskb_pull(skb, i)) 509 goto err; 510 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 511 skb->ip_summed = CHECKSUM_NONE; 512 } 513 } 514 515 /* Look for overlap with succeeding segments. 516 * If we can merge fragments, do it. 517 */ 518 while (next && FRAG6_CB(next)->offset < end) { 519 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */ 520 521 if (i < next->len) { 522 /* Eat head of the next overlapped fragment 523 * and leave the loop. The next ones cannot overlap. 524 */ 525 if (!pskb_pull(next, i)) 526 goto err; 527 FRAG6_CB(next)->offset += i; /* next fragment */ 528 fq->meat -= i; 529 if (next->ip_summed != CHECKSUM_UNNECESSARY) 530 next->ip_summed = CHECKSUM_NONE; 531 break; 532 } else { 533 struct sk_buff *free_it = next; 534 535 /* Old fragment is completely overridden with 536 * new one drop it. 537 */ 538 next = next->next; 539 540 if (prev) 541 prev->next = next; 542 else 543 fq->fragments = next; 544 545 fq->meat -= free_it->len; 546 frag_kfree_skb(free_it, NULL); 547 } 548 } 549 550 FRAG6_CB(skb)->offset = offset; 551 552 /* Insert this fragment in the chain of fragments. */ 553 skb->next = next; 554 if (prev) 555 prev->next = skb; 556 else 557 fq->fragments = skb; 558 559 if (skb->dev) 560 fq->iif = skb->dev->ifindex; 561 skb->dev = NULL; 562 skb_get_timestamp(skb, &fq->stamp); 563 fq->meat += skb->len; 564 atomic_add(skb->truesize, &ip6_frag_mem); 565 566 /* The first fragment. 567 * nhoffset is obtained from the first fragment, of course. 568 */ 569 if (offset == 0) { 570 fq->nhoffset = nhoff; 571 fq->last_in |= FIRST_IN; 572 } 573 write_lock(&ip6_frag_lock); 574 list_move_tail(&fq->lru_list, &ip6_frag_lru_list); 575 write_unlock(&ip6_frag_lock); 576 return; 577 578 err: 579 IP6_INC_STATS(IPSTATS_MIB_REASMFAILS); 580 kfree_skb(skb); 581 } 582 583 /* 584 * Check if this packet is complete. 585 * Returns NULL on failure by any reason, and pointer 586 * to current nexthdr field in reassembled frame. 587 * 588 * It is called with locked fq, and caller must check that 589 * queue is eligible for reassembly i.e. it is not COMPLETE, 590 * the last and the first frames arrived and all the bits are here. 591 */ 592 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in, 593 unsigned int *nhoffp, 594 struct net_device *dev) 595 { 596 struct sk_buff *fp, *head = fq->fragments; 597 int payload_len; 598 unsigned int nhoff; 599 600 fq_kill(fq); 601 602 BUG_TRAP(head != NULL); 603 BUG_TRAP(FRAG6_CB(head)->offset == 0); 604 605 /* Unfragmented part is taken from the first segment. */ 606 payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr); 607 if (payload_len > IPV6_MAXPLEN) 608 goto out_oversize; 609 610 /* Head of list must not be cloned. */ 611 if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) 612 goto out_oom; 613 614 /* If the first fragment is fragmented itself, we split 615 * it to two chunks: the first with data and paged part 616 * and the second, holding only fragments. */ 617 if (skb_shinfo(head)->frag_list) { 618 struct sk_buff *clone; 619 int i, plen = 0; 620 621 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 622 goto out_oom; 623 clone->next = head->next; 624 head->next = clone; 625 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 626 skb_shinfo(head)->frag_list = NULL; 627 for (i=0; i<skb_shinfo(head)->nr_frags; i++) 628 plen += skb_shinfo(head)->frags[i].size; 629 clone->len = clone->data_len = head->data_len - plen; 630 head->data_len -= clone->len; 631 head->len -= clone->len; 632 clone->csum = 0; 633 clone->ip_summed = head->ip_summed; 634 atomic_add(clone->truesize, &ip6_frag_mem); 635 } 636 637 /* We have to remove fragment header from datagram and to relocate 638 * header in order to calculate ICV correctly. */ 639 nhoff = fq->nhoffset; 640 head->nh.raw[nhoff] = head->h.raw[0]; 641 memmove(head->head + sizeof(struct frag_hdr), head->head, 642 (head->data - head->head) - sizeof(struct frag_hdr)); 643 head->mac.raw += sizeof(struct frag_hdr); 644 head->nh.raw += sizeof(struct frag_hdr); 645 646 skb_shinfo(head)->frag_list = head->next; 647 head->h.raw = head->data; 648 skb_push(head, head->data - head->nh.raw); 649 atomic_sub(head->truesize, &ip6_frag_mem); 650 651 for (fp=head->next; fp; fp = fp->next) { 652 head->data_len += fp->len; 653 head->len += fp->len; 654 if (head->ip_summed != fp->ip_summed) 655 head->ip_summed = CHECKSUM_NONE; 656 else if (head->ip_summed == CHECKSUM_HW) 657 head->csum = csum_add(head->csum, fp->csum); 658 head->truesize += fp->truesize; 659 atomic_sub(fp->truesize, &ip6_frag_mem); 660 } 661 662 head->next = NULL; 663 head->dev = dev; 664 skb_set_timestamp(head, &fq->stamp); 665 head->nh.ipv6h->payload_len = htons(payload_len); 666 667 *skb_in = head; 668 669 /* Yes, and fold redundant checksum back. 8) */ 670 if (head->ip_summed == CHECKSUM_HW) 671 head->csum = csum_partial(head->nh.raw, head->h.raw-head->nh.raw, head->csum); 672 673 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS); 674 fq->fragments = NULL; 675 *nhoffp = nhoff; 676 return 1; 677 678 out_oversize: 679 if (net_ratelimit()) 680 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len); 681 goto out_fail; 682 out_oom: 683 if (net_ratelimit()) 684 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n"); 685 out_fail: 686 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 687 return -1; 688 } 689 690 static int ipv6_frag_rcv(struct sk_buff **skbp, unsigned int *nhoffp) 691 { 692 struct sk_buff *skb = *skbp; 693 struct net_device *dev = skb->dev; 694 struct frag_hdr *fhdr; 695 struct frag_queue *fq; 696 struct ipv6hdr *hdr; 697 698 hdr = skb->nh.ipv6h; 699 700 IP6_INC_STATS_BH(IPSTATS_MIB_REASMREQDS); 701 702 /* Jumbo payload inhibits frag. header */ 703 if (hdr->payload_len==0) { 704 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS); 705 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw); 706 return -1; 707 } 708 if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+sizeof(struct frag_hdr))) { 709 IP6_INC_STATS(IPSTATS_MIB_INHDRERRORS); 710 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw); 711 return -1; 712 } 713 714 hdr = skb->nh.ipv6h; 715 fhdr = (struct frag_hdr *)skb->h.raw; 716 717 if (!(fhdr->frag_off & htons(0xFFF9))) { 718 /* It is not a fragmented frame */ 719 skb->h.raw += sizeof(struct frag_hdr); 720 IP6_INC_STATS_BH(IPSTATS_MIB_REASMOKS); 721 722 *nhoffp = (u8*)fhdr - skb->nh.raw; 723 return 1; 724 } 725 726 if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh) 727 ip6_evictor(); 728 729 if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr)) != NULL) { 730 int ret = -1; 731 732 spin_lock(&fq->lock); 733 734 ip6_frag_queue(fq, skb, fhdr, *nhoffp); 735 736 if (fq->last_in == (FIRST_IN|LAST_IN) && 737 fq->meat == fq->len) 738 ret = ip6_frag_reasm(fq, skbp, nhoffp, dev); 739 740 spin_unlock(&fq->lock); 741 fq_put(fq, NULL); 742 return ret; 743 } 744 745 IP6_INC_STATS_BH(IPSTATS_MIB_REASMFAILS); 746 kfree_skb(skb); 747 return -1; 748 } 749 750 static struct inet6_protocol frag_protocol = 751 { 752 .handler = ipv6_frag_rcv, 753 .flags = INET6_PROTO_NOPOLICY, 754 }; 755 756 void __init ipv6_frag_init(void) 757 { 758 if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0) 759 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n"); 760 761 ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^ 762 (jiffies ^ (jiffies >> 6))); 763 764 init_timer(&ip6_frag_secret_timer); 765 ip6_frag_secret_timer.function = ip6_frag_secret_rebuild; 766 ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval; 767 add_timer(&ip6_frag_secret_timer); 768 } 769