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 58 int sysctl_ip6frag_high_thresh __read_mostly = 256*1024; 59 int sysctl_ip6frag_low_thresh __read_mostly = 192*1024; 60 61 int sysctl_ip6frag_time __read_mostly = IPV6_FRAG_TIMEOUT; 62 63 struct ip6frag_skb_cb 64 { 65 struct inet6_skb_parm h; 66 int offset; 67 }; 68 69 #define FRAG6_CB(skb) ((struct ip6frag_skb_cb*)((skb)->cb)) 70 71 72 /* 73 * Equivalent of ipv4 struct ipq 74 */ 75 76 struct frag_queue 77 { 78 struct hlist_node list; 79 struct list_head lru_list; /* lru list member */ 80 81 __be32 id; /* fragment id */ 82 struct in6_addr saddr; 83 struct in6_addr daddr; 84 85 spinlock_t lock; 86 atomic_t refcnt; 87 struct timer_list timer; /* expire timer */ 88 struct sk_buff *fragments; 89 int len; 90 int meat; 91 int iif; 92 ktime_t stamp; 93 unsigned int csum; 94 __u8 last_in; /* has first/last segment arrived? */ 95 #define COMPLETE 4 96 #define FIRST_IN 2 97 #define LAST_IN 1 98 __u16 nhoffset; 99 }; 100 101 /* Hash table. */ 102 103 #define IP6Q_HASHSZ 64 104 105 static struct hlist_head 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 int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 112 struct net_device *dev); 113 114 static __inline__ void __fq_unlink(struct frag_queue *fq) 115 { 116 hlist_del(&fq->list); 117 list_del(&fq->lru_list); 118 ip6_frag_nqueues--; 119 } 120 121 static __inline__ void fq_unlink(struct frag_queue *fq) 122 { 123 write_lock(&ip6_frag_lock); 124 __fq_unlink(fq); 125 write_unlock(&ip6_frag_lock); 126 } 127 128 /* 129 * callers should be careful not to use the hash value outside the ipfrag_lock 130 * as doing so could race with ipfrag_hash_rnd being recalculated. 131 */ 132 static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr, 133 struct in6_addr *daddr) 134 { 135 u32 a, b, c; 136 137 a = (__force u32)saddr->s6_addr32[0]; 138 b = (__force u32)saddr->s6_addr32[1]; 139 c = (__force u32)saddr->s6_addr32[2]; 140 141 a += JHASH_GOLDEN_RATIO; 142 b += JHASH_GOLDEN_RATIO; 143 c += ip6_frag_hash_rnd; 144 __jhash_mix(a, b, c); 145 146 a += (__force u32)saddr->s6_addr32[3]; 147 b += (__force u32)daddr->s6_addr32[0]; 148 c += (__force u32)daddr->s6_addr32[1]; 149 __jhash_mix(a, b, c); 150 151 a += (__force u32)daddr->s6_addr32[2]; 152 b += (__force u32)daddr->s6_addr32[3]; 153 c += (__force u32)id; 154 __jhash_mix(a, b, c); 155 156 return c & (IP6Q_HASHSZ - 1); 157 } 158 159 static struct timer_list ip6_frag_secret_timer; 160 int sysctl_ip6frag_secret_interval __read_mostly = 10 * 60 * HZ; 161 162 static void ip6_frag_secret_rebuild(unsigned long dummy) 163 { 164 unsigned long now = jiffies; 165 int i; 166 167 write_lock(&ip6_frag_lock); 168 get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32)); 169 for (i = 0; i < IP6Q_HASHSZ; i++) { 170 struct frag_queue *q; 171 struct hlist_node *p, *n; 172 173 hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], list) { 174 unsigned int hval = ip6qhashfn(q->id, 175 &q->saddr, 176 &q->daddr); 177 178 if (hval != i) { 179 hlist_del(&q->list); 180 181 /* Relink to new hash chain. */ 182 hlist_add_head(&q->list, 183 &ip6_frag_hash[hval]); 184 185 } 186 } 187 } 188 write_unlock(&ip6_frag_lock); 189 190 mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval); 191 } 192 193 atomic_t ip6_frag_mem = ATOMIC_INIT(0); 194 195 /* Memory Tracking Functions. */ 196 static inline void frag_kfree_skb(struct sk_buff *skb, int *work) 197 { 198 if (work) 199 *work -= skb->truesize; 200 atomic_sub(skb->truesize, &ip6_frag_mem); 201 kfree_skb(skb); 202 } 203 204 static inline void frag_free_queue(struct frag_queue *fq, int *work) 205 { 206 if (work) 207 *work -= sizeof(struct frag_queue); 208 atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem); 209 kfree(fq); 210 } 211 212 static inline struct frag_queue *frag_alloc_queue(void) 213 { 214 struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC); 215 216 if(!fq) 217 return NULL; 218 atomic_add(sizeof(struct frag_queue), &ip6_frag_mem); 219 return fq; 220 } 221 222 /* Destruction primitives. */ 223 224 /* Complete destruction of fq. */ 225 static void ip6_frag_destroy(struct frag_queue *fq, int *work) 226 { 227 struct sk_buff *fp; 228 229 BUG_TRAP(fq->last_in&COMPLETE); 230 BUG_TRAP(del_timer(&fq->timer) == 0); 231 232 /* Release all fragment data. */ 233 fp = fq->fragments; 234 while (fp) { 235 struct sk_buff *xp = fp->next; 236 237 frag_kfree_skb(fp, work); 238 fp = xp; 239 } 240 241 frag_free_queue(fq, work); 242 } 243 244 static __inline__ void fq_put(struct frag_queue *fq, int *work) 245 { 246 if (atomic_dec_and_test(&fq->refcnt)) 247 ip6_frag_destroy(fq, work); 248 } 249 250 /* Kill fq entry. It is not destroyed immediately, 251 * because caller (and someone more) holds reference count. 252 */ 253 static __inline__ void fq_kill(struct frag_queue *fq) 254 { 255 if (del_timer(&fq->timer)) 256 atomic_dec(&fq->refcnt); 257 258 if (!(fq->last_in & COMPLETE)) { 259 fq_unlink(fq); 260 atomic_dec(&fq->refcnt); 261 fq->last_in |= COMPLETE; 262 } 263 } 264 265 static void ip6_evictor(struct inet6_dev *idev) 266 { 267 struct frag_queue *fq; 268 struct list_head *tmp; 269 int work; 270 271 work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh; 272 if (work <= 0) 273 return; 274 275 while(work > 0) { 276 read_lock(&ip6_frag_lock); 277 if (list_empty(&ip6_frag_lru_list)) { 278 read_unlock(&ip6_frag_lock); 279 return; 280 } 281 tmp = ip6_frag_lru_list.next; 282 fq = list_entry(tmp, struct frag_queue, lru_list); 283 atomic_inc(&fq->refcnt); 284 read_unlock(&ip6_frag_lock); 285 286 spin_lock(&fq->lock); 287 if (!(fq->last_in&COMPLETE)) 288 fq_kill(fq); 289 spin_unlock(&fq->lock); 290 291 fq_put(fq, &work); 292 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS); 293 } 294 } 295 296 static void ip6_frag_expire(unsigned long data) 297 { 298 struct frag_queue *fq = (struct frag_queue *) data; 299 struct net_device *dev = NULL; 300 301 spin_lock(&fq->lock); 302 303 if (fq->last_in & COMPLETE) 304 goto out; 305 306 fq_kill(fq); 307 308 dev = dev_get_by_index(&init_net, fq->iif); 309 if (!dev) 310 goto out; 311 312 rcu_read_lock(); 313 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT); 314 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 315 rcu_read_unlock(); 316 317 /* Don't send error if the first segment did not arrive. */ 318 if (!(fq->last_in&FIRST_IN) || !fq->fragments) 319 goto out; 320 321 /* 322 But use as source device on which LAST ARRIVED 323 segment was received. And do not use fq->dev 324 pointer directly, device might already disappeared. 325 */ 326 fq->fragments->dev = dev; 327 icmpv6_send(fq->fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev); 328 out: 329 if (dev) 330 dev_put(dev); 331 spin_unlock(&fq->lock); 332 fq_put(fq, NULL); 333 } 334 335 /* Creation primitives. */ 336 337 338 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in) 339 { 340 struct frag_queue *fq; 341 unsigned int hash; 342 #ifdef CONFIG_SMP 343 struct hlist_node *n; 344 #endif 345 346 write_lock(&ip6_frag_lock); 347 hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr); 348 #ifdef CONFIG_SMP 349 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { 350 if (fq->id == fq_in->id && 351 ipv6_addr_equal(&fq_in->saddr, &fq->saddr) && 352 ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) { 353 atomic_inc(&fq->refcnt); 354 write_unlock(&ip6_frag_lock); 355 fq_in->last_in |= COMPLETE; 356 fq_put(fq_in, NULL); 357 return fq; 358 } 359 } 360 #endif 361 fq = fq_in; 362 363 if (!mod_timer(&fq->timer, jiffies + sysctl_ip6frag_time)) 364 atomic_inc(&fq->refcnt); 365 366 atomic_inc(&fq->refcnt); 367 hlist_add_head(&fq->list, &ip6_frag_hash[hash]); 368 INIT_LIST_HEAD(&fq->lru_list); 369 list_add_tail(&fq->lru_list, &ip6_frag_lru_list); 370 ip6_frag_nqueues++; 371 write_unlock(&ip6_frag_lock); 372 return fq; 373 } 374 375 376 static struct frag_queue * 377 ip6_frag_create(__be32 id, struct in6_addr *src, struct in6_addr *dst, 378 struct inet6_dev *idev) 379 { 380 struct frag_queue *fq; 381 382 if ((fq = frag_alloc_queue()) == NULL) 383 goto oom; 384 385 fq->id = id; 386 ipv6_addr_copy(&fq->saddr, src); 387 ipv6_addr_copy(&fq->daddr, dst); 388 389 init_timer(&fq->timer); 390 fq->timer.function = ip6_frag_expire; 391 fq->timer.data = (long) fq; 392 spin_lock_init(&fq->lock); 393 atomic_set(&fq->refcnt, 1); 394 395 return ip6_frag_intern(fq); 396 397 oom: 398 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS); 399 return NULL; 400 } 401 402 static __inline__ struct frag_queue * 403 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst, 404 struct inet6_dev *idev) 405 { 406 struct frag_queue *fq; 407 struct hlist_node *n; 408 unsigned int hash; 409 410 read_lock(&ip6_frag_lock); 411 hash = ip6qhashfn(id, src, dst); 412 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], list) { 413 if (fq->id == id && 414 ipv6_addr_equal(src, &fq->saddr) && 415 ipv6_addr_equal(dst, &fq->daddr)) { 416 atomic_inc(&fq->refcnt); 417 read_unlock(&ip6_frag_lock); 418 return fq; 419 } 420 } 421 read_unlock(&ip6_frag_lock); 422 423 return ip6_frag_create(id, src, dst, idev); 424 } 425 426 427 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 428 struct frag_hdr *fhdr, int nhoff) 429 { 430 struct sk_buff *prev, *next; 431 struct net_device *dev; 432 int offset, end; 433 434 if (fq->last_in & COMPLETE) 435 goto err; 436 437 offset = ntohs(fhdr->frag_off) & ~0x7; 438 end = offset + (ntohs(ipv6_hdr(skb)->payload_len) - 439 ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1))); 440 441 if ((unsigned int)end > IPV6_MAXPLEN) { 442 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), 443 IPSTATS_MIB_INHDRERRORS); 444 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 445 ((u8 *)&fhdr->frag_off - 446 skb_network_header(skb))); 447 return -1; 448 } 449 450 if (skb->ip_summed == CHECKSUM_COMPLETE) { 451 const unsigned char *nh = skb_network_header(skb); 452 skb->csum = csum_sub(skb->csum, 453 csum_partial(nh, (u8 *)(fhdr + 1) - nh, 454 0)); 455 } 456 457 /* Is this the final fragment? */ 458 if (!(fhdr->frag_off & htons(IP6_MF))) { 459 /* If we already have some bits beyond end 460 * or have different end, the segment is corrupted. 461 */ 462 if (end < fq->len || 463 ((fq->last_in & LAST_IN) && end != fq->len)) 464 goto err; 465 fq->last_in |= LAST_IN; 466 fq->len = end; 467 } else { 468 /* Check if the fragment is rounded to 8 bytes. 469 * Required by the RFC. 470 */ 471 if (end & 0x7) { 472 /* RFC2460 says always send parameter problem in 473 * this case. -DaveM 474 */ 475 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), 476 IPSTATS_MIB_INHDRERRORS); 477 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 478 offsetof(struct ipv6hdr, payload_len)); 479 return -1; 480 } 481 if (end > fq->len) { 482 /* Some bits beyond end -> corruption. */ 483 if (fq->last_in & LAST_IN) 484 goto err; 485 fq->len = end; 486 } 487 } 488 489 if (end == offset) 490 goto err; 491 492 /* Point into the IP datagram 'data' part. */ 493 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) 494 goto err; 495 496 if (pskb_trim_rcsum(skb, end - offset)) 497 goto err; 498 499 /* Find out which fragments are in front and at the back of us 500 * in the chain of fragments so far. We must know where to put 501 * this fragment, right? 502 */ 503 prev = NULL; 504 for(next = fq->fragments; next != NULL; next = next->next) { 505 if (FRAG6_CB(next)->offset >= offset) 506 break; /* bingo! */ 507 prev = next; 508 } 509 510 /* We found where to put this one. Check for overlap with 511 * preceding fragment, and, if needed, align things so that 512 * any overlaps are eliminated. 513 */ 514 if (prev) { 515 int i = (FRAG6_CB(prev)->offset + prev->len) - offset; 516 517 if (i > 0) { 518 offset += i; 519 if (end <= offset) 520 goto err; 521 if (!pskb_pull(skb, i)) 522 goto err; 523 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 524 skb->ip_summed = CHECKSUM_NONE; 525 } 526 } 527 528 /* Look for overlap with succeeding segments. 529 * If we can merge fragments, do it. 530 */ 531 while (next && FRAG6_CB(next)->offset < end) { 532 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */ 533 534 if (i < next->len) { 535 /* Eat head of the next overlapped fragment 536 * and leave the loop. The next ones cannot overlap. 537 */ 538 if (!pskb_pull(next, i)) 539 goto err; 540 FRAG6_CB(next)->offset += i; /* next fragment */ 541 fq->meat -= i; 542 if (next->ip_summed != CHECKSUM_UNNECESSARY) 543 next->ip_summed = CHECKSUM_NONE; 544 break; 545 } else { 546 struct sk_buff *free_it = next; 547 548 /* Old fragment is completely overridden with 549 * new one drop it. 550 */ 551 next = next->next; 552 553 if (prev) 554 prev->next = next; 555 else 556 fq->fragments = next; 557 558 fq->meat -= free_it->len; 559 frag_kfree_skb(free_it, NULL); 560 } 561 } 562 563 FRAG6_CB(skb)->offset = offset; 564 565 /* Insert this fragment in the chain of fragments. */ 566 skb->next = next; 567 if (prev) 568 prev->next = skb; 569 else 570 fq->fragments = skb; 571 572 dev = skb->dev; 573 if (dev) { 574 fq->iif = dev->ifindex; 575 skb->dev = NULL; 576 } 577 fq->stamp = skb->tstamp; 578 fq->meat += skb->len; 579 atomic_add(skb->truesize, &ip6_frag_mem); 580 581 /* The first fragment. 582 * nhoffset is obtained from the first fragment, of course. 583 */ 584 if (offset == 0) { 585 fq->nhoffset = nhoff; 586 fq->last_in |= FIRST_IN; 587 } 588 589 if (fq->last_in == (FIRST_IN | LAST_IN) && fq->meat == fq->len) 590 return ip6_frag_reasm(fq, prev, dev); 591 592 write_lock(&ip6_frag_lock); 593 list_move_tail(&fq->lru_list, &ip6_frag_lru_list); 594 write_unlock(&ip6_frag_lock); 595 return -1; 596 597 err: 598 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS); 599 kfree_skb(skb); 600 return -1; 601 } 602 603 /* 604 * Check if this packet is complete. 605 * Returns NULL on failure by any reason, and pointer 606 * to current nexthdr field in reassembled frame. 607 * 608 * It is called with locked fq, and caller must check that 609 * queue is eligible for reassembly i.e. it is not COMPLETE, 610 * the last and the first frames arrived and all the bits are here. 611 */ 612 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 613 struct net_device *dev) 614 { 615 struct sk_buff *fp, *head = fq->fragments; 616 int payload_len; 617 unsigned int nhoff; 618 619 fq_kill(fq); 620 621 /* Make the one we just received the head. */ 622 if (prev) { 623 head = prev->next; 624 fp = skb_clone(head, GFP_ATOMIC); 625 626 if (!fp) 627 goto out_oom; 628 629 fp->next = head->next; 630 prev->next = fp; 631 632 skb_morph(head, fq->fragments); 633 head->next = fq->fragments->next; 634 635 kfree_skb(fq->fragments); 636 fq->fragments = head; 637 } 638 639 BUG_TRAP(head != NULL); 640 BUG_TRAP(FRAG6_CB(head)->offset == 0); 641 642 /* Unfragmented part is taken from the first segment. */ 643 payload_len = ((head->data - skb_network_header(head)) - 644 sizeof(struct ipv6hdr) + fq->len - 645 sizeof(struct frag_hdr)); 646 if (payload_len > IPV6_MAXPLEN) 647 goto out_oversize; 648 649 /* Head of list must not be cloned. */ 650 if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) 651 goto out_oom; 652 653 /* If the first fragment is fragmented itself, we split 654 * it to two chunks: the first with data and paged part 655 * and the second, holding only fragments. */ 656 if (skb_shinfo(head)->frag_list) { 657 struct sk_buff *clone; 658 int i, plen = 0; 659 660 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 661 goto out_oom; 662 clone->next = head->next; 663 head->next = clone; 664 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 665 skb_shinfo(head)->frag_list = NULL; 666 for (i=0; i<skb_shinfo(head)->nr_frags; i++) 667 plen += skb_shinfo(head)->frags[i].size; 668 clone->len = clone->data_len = head->data_len - plen; 669 head->data_len -= clone->len; 670 head->len -= clone->len; 671 clone->csum = 0; 672 clone->ip_summed = head->ip_summed; 673 atomic_add(clone->truesize, &ip6_frag_mem); 674 } 675 676 /* We have to remove fragment header from datagram and to relocate 677 * header in order to calculate ICV correctly. */ 678 nhoff = fq->nhoffset; 679 skb_network_header(head)[nhoff] = skb_transport_header(head)[0]; 680 memmove(head->head + sizeof(struct frag_hdr), head->head, 681 (head->data - head->head) - sizeof(struct frag_hdr)); 682 head->mac_header += sizeof(struct frag_hdr); 683 head->network_header += sizeof(struct frag_hdr); 684 685 skb_shinfo(head)->frag_list = head->next; 686 skb_reset_transport_header(head); 687 skb_push(head, head->data - skb_network_header(head)); 688 atomic_sub(head->truesize, &ip6_frag_mem); 689 690 for (fp=head->next; fp; fp = fp->next) { 691 head->data_len += fp->len; 692 head->len += fp->len; 693 if (head->ip_summed != fp->ip_summed) 694 head->ip_summed = CHECKSUM_NONE; 695 else if (head->ip_summed == CHECKSUM_COMPLETE) 696 head->csum = csum_add(head->csum, fp->csum); 697 head->truesize += fp->truesize; 698 atomic_sub(fp->truesize, &ip6_frag_mem); 699 } 700 701 head->next = NULL; 702 head->dev = dev; 703 head->tstamp = fq->stamp; 704 ipv6_hdr(head)->payload_len = htons(payload_len); 705 IP6CB(head)->nhoff = nhoff; 706 707 /* Yes, and fold redundant checksum back. 8) */ 708 if (head->ip_summed == CHECKSUM_COMPLETE) 709 head->csum = csum_partial(skb_network_header(head), 710 skb_network_header_len(head), 711 head->csum); 712 713 rcu_read_lock(); 714 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS); 715 rcu_read_unlock(); 716 fq->fragments = NULL; 717 return 1; 718 719 out_oversize: 720 if (net_ratelimit()) 721 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len); 722 goto out_fail; 723 out_oom: 724 if (net_ratelimit()) 725 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n"); 726 out_fail: 727 rcu_read_lock(); 728 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 729 rcu_read_unlock(); 730 return -1; 731 } 732 733 static int ipv6_frag_rcv(struct sk_buff **skbp) 734 { 735 struct sk_buff *skb = *skbp; 736 struct frag_hdr *fhdr; 737 struct frag_queue *fq; 738 struct ipv6hdr *hdr = ipv6_hdr(skb); 739 740 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS); 741 742 /* Jumbo payload inhibits frag. header */ 743 if (hdr->payload_len==0) { 744 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); 745 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 746 skb_network_header_len(skb)); 747 return -1; 748 } 749 if (!pskb_may_pull(skb, (skb_transport_offset(skb) + 750 sizeof(struct frag_hdr)))) { 751 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); 752 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 753 skb_network_header_len(skb)); 754 return -1; 755 } 756 757 hdr = ipv6_hdr(skb); 758 fhdr = (struct frag_hdr *)skb_transport_header(skb); 759 760 if (!(fhdr->frag_off & htons(0xFFF9))) { 761 /* It is not a fragmented frame */ 762 skb->transport_header += sizeof(struct frag_hdr); 763 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS); 764 765 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb); 766 return 1; 767 } 768 769 if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh) 770 ip6_evictor(ip6_dst_idev(skb->dst)); 771 772 if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr, 773 ip6_dst_idev(skb->dst))) != NULL) { 774 int ret; 775 776 spin_lock(&fq->lock); 777 778 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); 779 780 spin_unlock(&fq->lock); 781 fq_put(fq, NULL); 782 return ret; 783 } 784 785 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS); 786 kfree_skb(skb); 787 return -1; 788 } 789 790 static struct inet6_protocol frag_protocol = 791 { 792 .handler = ipv6_frag_rcv, 793 .flags = INET6_PROTO_NOPOLICY, 794 }; 795 796 void __init ipv6_frag_init(void) 797 { 798 if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0) 799 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n"); 800 801 ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^ 802 (jiffies ^ (jiffies >> 6))); 803 804 init_timer(&ip6_frag_secret_timer); 805 ip6_frag_secret_timer.function = ip6_frag_secret_rebuild; 806 ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval; 807 add_timer(&ip6_frag_secret_timer); 808 } 809