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 int sysctl_ip6frag_high_thresh __read_mostly = 256*1024; 60 int sysctl_ip6frag_low_thresh __read_mostly = 192*1024; 61 62 int sysctl_ip6frag_time __read_mostly = IPV6_FRAG_TIMEOUT; 63 64 struct ip6frag_skb_cb 65 { 66 struct inet6_skb_parm h; 67 int offset; 68 }; 69 70 #define FRAG6_CB(skb) ((struct ip6frag_skb_cb*)((skb)->cb)) 71 72 73 /* 74 * Equivalent of ipv4 struct ipq 75 */ 76 77 struct frag_queue 78 { 79 struct inet_frag_queue q; 80 81 __be32 id; /* fragment id */ 82 struct in6_addr saddr; 83 struct in6_addr daddr; 84 85 int iif; 86 unsigned int csum; 87 __u16 nhoffset; 88 }; 89 90 /* Hash table. */ 91 92 #define IP6Q_HASHSZ 64 93 94 static struct hlist_head ip6_frag_hash[IP6Q_HASHSZ]; 95 static DEFINE_RWLOCK(ip6_frag_lock); 96 static u32 ip6_frag_hash_rnd; 97 static LIST_HEAD(ip6_frag_lru_list); 98 int ip6_frag_nqueues = 0; 99 100 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 101 struct net_device *dev); 102 103 static __inline__ void __fq_unlink(struct frag_queue *fq) 104 { 105 hlist_del(&fq->q.list); 106 list_del(&fq->q.lru_list); 107 ip6_frag_nqueues--; 108 } 109 110 static __inline__ void fq_unlink(struct frag_queue *fq) 111 { 112 write_lock(&ip6_frag_lock); 113 __fq_unlink(fq); 114 write_unlock(&ip6_frag_lock); 115 } 116 117 /* 118 * callers should be careful not to use the hash value outside the ipfrag_lock 119 * as doing so could race with ipfrag_hash_rnd being recalculated. 120 */ 121 static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr, 122 struct in6_addr *daddr) 123 { 124 u32 a, b, c; 125 126 a = (__force u32)saddr->s6_addr32[0]; 127 b = (__force u32)saddr->s6_addr32[1]; 128 c = (__force u32)saddr->s6_addr32[2]; 129 130 a += JHASH_GOLDEN_RATIO; 131 b += JHASH_GOLDEN_RATIO; 132 c += ip6_frag_hash_rnd; 133 __jhash_mix(a, b, c); 134 135 a += (__force u32)saddr->s6_addr32[3]; 136 b += (__force u32)daddr->s6_addr32[0]; 137 c += (__force u32)daddr->s6_addr32[1]; 138 __jhash_mix(a, b, c); 139 140 a += (__force u32)daddr->s6_addr32[2]; 141 b += (__force u32)daddr->s6_addr32[3]; 142 c += (__force u32)id; 143 __jhash_mix(a, b, c); 144 145 return c & (IP6Q_HASHSZ - 1); 146 } 147 148 static struct timer_list ip6_frag_secret_timer; 149 int sysctl_ip6frag_secret_interval __read_mostly = 10 * 60 * HZ; 150 151 static void ip6_frag_secret_rebuild(unsigned long dummy) 152 { 153 unsigned long now = jiffies; 154 int i; 155 156 write_lock(&ip6_frag_lock); 157 get_random_bytes(&ip6_frag_hash_rnd, sizeof(u32)); 158 for (i = 0; i < IP6Q_HASHSZ; i++) { 159 struct frag_queue *q; 160 struct hlist_node *p, *n; 161 162 hlist_for_each_entry_safe(q, p, n, &ip6_frag_hash[i], q.list) { 163 unsigned int hval = ip6qhashfn(q->id, 164 &q->saddr, 165 &q->daddr); 166 167 if (hval != i) { 168 hlist_del(&q->q.list); 169 170 /* Relink to new hash chain. */ 171 hlist_add_head(&q->q.list, 172 &ip6_frag_hash[hval]); 173 174 } 175 } 176 } 177 write_unlock(&ip6_frag_lock); 178 179 mod_timer(&ip6_frag_secret_timer, now + sysctl_ip6frag_secret_interval); 180 } 181 182 atomic_t ip6_frag_mem = ATOMIC_INIT(0); 183 184 /* Memory Tracking Functions. */ 185 static inline void frag_kfree_skb(struct sk_buff *skb, int *work) 186 { 187 if (work) 188 *work -= skb->truesize; 189 atomic_sub(skb->truesize, &ip6_frag_mem); 190 kfree_skb(skb); 191 } 192 193 static inline void frag_free_queue(struct frag_queue *fq, int *work) 194 { 195 if (work) 196 *work -= sizeof(struct frag_queue); 197 atomic_sub(sizeof(struct frag_queue), &ip6_frag_mem); 198 kfree(fq); 199 } 200 201 static inline struct frag_queue *frag_alloc_queue(void) 202 { 203 struct frag_queue *fq = kzalloc(sizeof(struct frag_queue), GFP_ATOMIC); 204 205 if(!fq) 206 return NULL; 207 atomic_add(sizeof(struct frag_queue), &ip6_frag_mem); 208 return fq; 209 } 210 211 /* Destruction primitives. */ 212 213 /* Complete destruction of fq. */ 214 static void ip6_frag_destroy(struct frag_queue *fq, int *work) 215 { 216 struct sk_buff *fp; 217 218 BUG_TRAP(fq->q.last_in&COMPLETE); 219 BUG_TRAP(del_timer(&fq->q.timer) == 0); 220 221 /* Release all fragment data. */ 222 fp = fq->q.fragments; 223 while (fp) { 224 struct sk_buff *xp = fp->next; 225 226 frag_kfree_skb(fp, work); 227 fp = xp; 228 } 229 230 frag_free_queue(fq, work); 231 } 232 233 static __inline__ void fq_put(struct frag_queue *fq, int *work) 234 { 235 if (atomic_dec_and_test(&fq->q.refcnt)) 236 ip6_frag_destroy(fq, work); 237 } 238 239 /* Kill fq entry. It is not destroyed immediately, 240 * because caller (and someone more) holds reference count. 241 */ 242 static __inline__ void fq_kill(struct frag_queue *fq) 243 { 244 if (del_timer(&fq->q.timer)) 245 atomic_dec(&fq->q.refcnt); 246 247 if (!(fq->q.last_in & COMPLETE)) { 248 fq_unlink(fq); 249 atomic_dec(&fq->q.refcnt); 250 fq->q.last_in |= COMPLETE; 251 } 252 } 253 254 static void ip6_evictor(struct inet6_dev *idev) 255 { 256 struct frag_queue *fq; 257 struct list_head *tmp; 258 int work; 259 260 work = atomic_read(&ip6_frag_mem) - sysctl_ip6frag_low_thresh; 261 if (work <= 0) 262 return; 263 264 while(work > 0) { 265 read_lock(&ip6_frag_lock); 266 if (list_empty(&ip6_frag_lru_list)) { 267 read_unlock(&ip6_frag_lock); 268 return; 269 } 270 tmp = ip6_frag_lru_list.next; 271 fq = list_entry(tmp, struct frag_queue, q.lru_list); 272 atomic_inc(&fq->q.refcnt); 273 read_unlock(&ip6_frag_lock); 274 275 spin_lock(&fq->q.lock); 276 if (!(fq->q.last_in&COMPLETE)) 277 fq_kill(fq); 278 spin_unlock(&fq->q.lock); 279 280 fq_put(fq, &work); 281 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS); 282 } 283 } 284 285 static void ip6_frag_expire(unsigned long data) 286 { 287 struct frag_queue *fq = (struct frag_queue *) data; 288 struct net_device *dev = NULL; 289 290 spin_lock(&fq->q.lock); 291 292 if (fq->q.last_in & COMPLETE) 293 goto out; 294 295 fq_kill(fq); 296 297 dev = dev_get_by_index(&init_net, fq->iif); 298 if (!dev) 299 goto out; 300 301 rcu_read_lock(); 302 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT); 303 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 304 rcu_read_unlock(); 305 306 /* Don't send error if the first segment did not arrive. */ 307 if (!(fq->q.last_in&FIRST_IN) || !fq->q.fragments) 308 goto out; 309 310 /* 311 But use as source device on which LAST ARRIVED 312 segment was received. And do not use fq->dev 313 pointer directly, device might already disappeared. 314 */ 315 fq->q.fragments->dev = dev; 316 icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev); 317 out: 318 if (dev) 319 dev_put(dev); 320 spin_unlock(&fq->q.lock); 321 fq_put(fq, NULL); 322 } 323 324 /* Creation primitives. */ 325 326 327 static struct frag_queue *ip6_frag_intern(struct frag_queue *fq_in) 328 { 329 struct frag_queue *fq; 330 unsigned int hash; 331 #ifdef CONFIG_SMP 332 struct hlist_node *n; 333 #endif 334 335 write_lock(&ip6_frag_lock); 336 hash = ip6qhashfn(fq_in->id, &fq_in->saddr, &fq_in->daddr); 337 #ifdef CONFIG_SMP 338 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], q.list) { 339 if (fq->id == fq_in->id && 340 ipv6_addr_equal(&fq_in->saddr, &fq->saddr) && 341 ipv6_addr_equal(&fq_in->daddr, &fq->daddr)) { 342 atomic_inc(&fq->q.refcnt); 343 write_unlock(&ip6_frag_lock); 344 fq_in->q.last_in |= COMPLETE; 345 fq_put(fq_in, NULL); 346 return fq; 347 } 348 } 349 #endif 350 fq = fq_in; 351 352 if (!mod_timer(&fq->q.timer, jiffies + sysctl_ip6frag_time)) 353 atomic_inc(&fq->q.refcnt); 354 355 atomic_inc(&fq->q.refcnt); 356 hlist_add_head(&fq->q.list, &ip6_frag_hash[hash]); 357 INIT_LIST_HEAD(&fq->q.lru_list); 358 list_add_tail(&fq->q.lru_list, &ip6_frag_lru_list); 359 ip6_frag_nqueues++; 360 write_unlock(&ip6_frag_lock); 361 return fq; 362 } 363 364 365 static struct frag_queue * 366 ip6_frag_create(__be32 id, struct in6_addr *src, struct in6_addr *dst, 367 struct inet6_dev *idev) 368 { 369 struct frag_queue *fq; 370 371 if ((fq = frag_alloc_queue()) == NULL) 372 goto oom; 373 374 fq->id = id; 375 ipv6_addr_copy(&fq->saddr, src); 376 ipv6_addr_copy(&fq->daddr, dst); 377 378 init_timer(&fq->q.timer); 379 fq->q.timer.function = ip6_frag_expire; 380 fq->q.timer.data = (long) fq; 381 spin_lock_init(&fq->q.lock); 382 atomic_set(&fq->q.refcnt, 1); 383 384 return ip6_frag_intern(fq); 385 386 oom: 387 IP6_INC_STATS_BH(idev, IPSTATS_MIB_REASMFAILS); 388 return NULL; 389 } 390 391 static __inline__ struct frag_queue * 392 fq_find(__be32 id, struct in6_addr *src, struct in6_addr *dst, 393 struct inet6_dev *idev) 394 { 395 struct frag_queue *fq; 396 struct hlist_node *n; 397 unsigned int hash; 398 399 read_lock(&ip6_frag_lock); 400 hash = ip6qhashfn(id, src, dst); 401 hlist_for_each_entry(fq, n, &ip6_frag_hash[hash], q.list) { 402 if (fq->id == id && 403 ipv6_addr_equal(src, &fq->saddr) && 404 ipv6_addr_equal(dst, &fq->daddr)) { 405 atomic_inc(&fq->q.refcnt); 406 read_unlock(&ip6_frag_lock); 407 return fq; 408 } 409 } 410 read_unlock(&ip6_frag_lock); 411 412 return ip6_frag_create(id, src, dst, idev); 413 } 414 415 416 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 417 struct frag_hdr *fhdr, int nhoff) 418 { 419 struct sk_buff *prev, *next; 420 struct net_device *dev; 421 int offset, end; 422 423 if (fq->q.last_in & COMPLETE) 424 goto err; 425 426 offset = ntohs(fhdr->frag_off) & ~0x7; 427 end = offset + (ntohs(ipv6_hdr(skb)->payload_len) - 428 ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1))); 429 430 if ((unsigned int)end > IPV6_MAXPLEN) { 431 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), 432 IPSTATS_MIB_INHDRERRORS); 433 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 434 ((u8 *)&fhdr->frag_off - 435 skb_network_header(skb))); 436 return -1; 437 } 438 439 if (skb->ip_summed == CHECKSUM_COMPLETE) { 440 const unsigned char *nh = skb_network_header(skb); 441 skb->csum = csum_sub(skb->csum, 442 csum_partial(nh, (u8 *)(fhdr + 1) - nh, 443 0)); 444 } 445 446 /* Is this the final fragment? */ 447 if (!(fhdr->frag_off & htons(IP6_MF))) { 448 /* If we already have some bits beyond end 449 * or have different end, the segment is corrupted. 450 */ 451 if (end < fq->q.len || 452 ((fq->q.last_in & LAST_IN) && end != fq->q.len)) 453 goto err; 454 fq->q.last_in |= LAST_IN; 455 fq->q.len = end; 456 } else { 457 /* Check if the fragment is rounded to 8 bytes. 458 * Required by the RFC. 459 */ 460 if (end & 0x7) { 461 /* RFC2460 says always send parameter problem in 462 * this case. -DaveM 463 */ 464 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), 465 IPSTATS_MIB_INHDRERRORS); 466 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 467 offsetof(struct ipv6hdr, payload_len)); 468 return -1; 469 } 470 if (end > fq->q.len) { 471 /* Some bits beyond end -> corruption. */ 472 if (fq->q.last_in & LAST_IN) 473 goto err; 474 fq->q.len = end; 475 } 476 } 477 478 if (end == offset) 479 goto err; 480 481 /* Point into the IP datagram 'data' part. */ 482 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) 483 goto err; 484 485 if (pskb_trim_rcsum(skb, end - offset)) 486 goto err; 487 488 /* Find out which fragments are in front and at the back of us 489 * in the chain of fragments so far. We must know where to put 490 * this fragment, right? 491 */ 492 prev = NULL; 493 for(next = fq->q.fragments; next != NULL; next = next->next) { 494 if (FRAG6_CB(next)->offset >= offset) 495 break; /* bingo! */ 496 prev = next; 497 } 498 499 /* We found where to put this one. Check for overlap with 500 * preceding fragment, and, if needed, align things so that 501 * any overlaps are eliminated. 502 */ 503 if (prev) { 504 int i = (FRAG6_CB(prev)->offset + prev->len) - offset; 505 506 if (i > 0) { 507 offset += i; 508 if (end <= offset) 509 goto err; 510 if (!pskb_pull(skb, i)) 511 goto err; 512 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 513 skb->ip_summed = CHECKSUM_NONE; 514 } 515 } 516 517 /* Look for overlap with succeeding segments. 518 * If we can merge fragments, do it. 519 */ 520 while (next && FRAG6_CB(next)->offset < end) { 521 int i = end - FRAG6_CB(next)->offset; /* overlap is 'i' bytes */ 522 523 if (i < next->len) { 524 /* Eat head of the next overlapped fragment 525 * and leave the loop. The next ones cannot overlap. 526 */ 527 if (!pskb_pull(next, i)) 528 goto err; 529 FRAG6_CB(next)->offset += i; /* next fragment */ 530 fq->q.meat -= i; 531 if (next->ip_summed != CHECKSUM_UNNECESSARY) 532 next->ip_summed = CHECKSUM_NONE; 533 break; 534 } else { 535 struct sk_buff *free_it = next; 536 537 /* Old fragment is completely overridden with 538 * new one drop it. 539 */ 540 next = next->next; 541 542 if (prev) 543 prev->next = next; 544 else 545 fq->q.fragments = next; 546 547 fq->q.meat -= free_it->len; 548 frag_kfree_skb(free_it, NULL); 549 } 550 } 551 552 FRAG6_CB(skb)->offset = offset; 553 554 /* Insert this fragment in the chain of fragments. */ 555 skb->next = next; 556 if (prev) 557 prev->next = skb; 558 else 559 fq->q.fragments = skb; 560 561 dev = skb->dev; 562 if (dev) { 563 fq->iif = dev->ifindex; 564 skb->dev = NULL; 565 } 566 fq->q.stamp = skb->tstamp; 567 fq->q.meat += skb->len; 568 atomic_add(skb->truesize, &ip6_frag_mem); 569 570 /* The first fragment. 571 * nhoffset is obtained from the first fragment, of course. 572 */ 573 if (offset == 0) { 574 fq->nhoffset = nhoff; 575 fq->q.last_in |= FIRST_IN; 576 } 577 578 if (fq->q.last_in == (FIRST_IN | LAST_IN) && fq->q.meat == fq->q.len) 579 return ip6_frag_reasm(fq, prev, dev); 580 581 write_lock(&ip6_frag_lock); 582 list_move_tail(&fq->q.lru_list, &ip6_frag_lru_list); 583 write_unlock(&ip6_frag_lock); 584 return -1; 585 586 err: 587 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS); 588 kfree_skb(skb); 589 return -1; 590 } 591 592 /* 593 * Check if this packet is complete. 594 * Returns NULL on failure by any reason, and pointer 595 * to current nexthdr field in reassembled frame. 596 * 597 * It is called with locked fq, and caller must check that 598 * queue is eligible for reassembly i.e. it is not COMPLETE, 599 * the last and the first frames arrived and all the bits are here. 600 */ 601 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 602 struct net_device *dev) 603 { 604 struct sk_buff *fp, *head = fq->q.fragments; 605 int payload_len; 606 unsigned int nhoff; 607 608 fq_kill(fq); 609 610 /* Make the one we just received the head. */ 611 if (prev) { 612 head = prev->next; 613 fp = skb_clone(head, GFP_ATOMIC); 614 615 if (!fp) 616 goto out_oom; 617 618 fp->next = head->next; 619 prev->next = fp; 620 621 skb_morph(head, fq->q.fragments); 622 head->next = fq->q.fragments->next; 623 624 kfree_skb(fq->q.fragments); 625 fq->q.fragments = head; 626 } 627 628 BUG_TRAP(head != NULL); 629 BUG_TRAP(FRAG6_CB(head)->offset == 0); 630 631 /* Unfragmented part is taken from the first segment. */ 632 payload_len = ((head->data - skb_network_header(head)) - 633 sizeof(struct ipv6hdr) + fq->q.len - 634 sizeof(struct frag_hdr)); 635 if (payload_len > IPV6_MAXPLEN) 636 goto out_oversize; 637 638 /* Head of list must not be cloned. */ 639 if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC)) 640 goto out_oom; 641 642 /* If the first fragment is fragmented itself, we split 643 * it to two chunks: the first with data and paged part 644 * and the second, holding only fragments. */ 645 if (skb_shinfo(head)->frag_list) { 646 struct sk_buff *clone; 647 int i, plen = 0; 648 649 if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL) 650 goto out_oom; 651 clone->next = head->next; 652 head->next = clone; 653 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 654 skb_shinfo(head)->frag_list = NULL; 655 for (i=0; i<skb_shinfo(head)->nr_frags; i++) 656 plen += skb_shinfo(head)->frags[i].size; 657 clone->len = clone->data_len = head->data_len - plen; 658 head->data_len -= clone->len; 659 head->len -= clone->len; 660 clone->csum = 0; 661 clone->ip_summed = head->ip_summed; 662 atomic_add(clone->truesize, &ip6_frag_mem); 663 } 664 665 /* We have to remove fragment header from datagram and to relocate 666 * header in order to calculate ICV correctly. */ 667 nhoff = fq->nhoffset; 668 skb_network_header(head)[nhoff] = skb_transport_header(head)[0]; 669 memmove(head->head + sizeof(struct frag_hdr), head->head, 670 (head->data - head->head) - sizeof(struct frag_hdr)); 671 head->mac_header += sizeof(struct frag_hdr); 672 head->network_header += sizeof(struct frag_hdr); 673 674 skb_shinfo(head)->frag_list = head->next; 675 skb_reset_transport_header(head); 676 skb_push(head, head->data - skb_network_header(head)); 677 atomic_sub(head->truesize, &ip6_frag_mem); 678 679 for (fp=head->next; fp; fp = fp->next) { 680 head->data_len += fp->len; 681 head->len += fp->len; 682 if (head->ip_summed != fp->ip_summed) 683 head->ip_summed = CHECKSUM_NONE; 684 else if (head->ip_summed == CHECKSUM_COMPLETE) 685 head->csum = csum_add(head->csum, fp->csum); 686 head->truesize += fp->truesize; 687 atomic_sub(fp->truesize, &ip6_frag_mem); 688 } 689 690 head->next = NULL; 691 head->dev = dev; 692 head->tstamp = fq->q.stamp; 693 ipv6_hdr(head)->payload_len = htons(payload_len); 694 IP6CB(head)->nhoff = nhoff; 695 696 /* Yes, and fold redundant checksum back. 8) */ 697 if (head->ip_summed == CHECKSUM_COMPLETE) 698 head->csum = csum_partial(skb_network_header(head), 699 skb_network_header_len(head), 700 head->csum); 701 702 rcu_read_lock(); 703 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMOKS); 704 rcu_read_unlock(); 705 fq->q.fragments = NULL; 706 return 1; 707 708 out_oversize: 709 if (net_ratelimit()) 710 printk(KERN_DEBUG "ip6_frag_reasm: payload len = %d\n", payload_len); 711 goto out_fail; 712 out_oom: 713 if (net_ratelimit()) 714 printk(KERN_DEBUG "ip6_frag_reasm: no memory for reassembly\n"); 715 out_fail: 716 rcu_read_lock(); 717 IP6_INC_STATS_BH(__in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 718 rcu_read_unlock(); 719 return -1; 720 } 721 722 static int ipv6_frag_rcv(struct sk_buff **skbp) 723 { 724 struct sk_buff *skb = *skbp; 725 struct frag_hdr *fhdr; 726 struct frag_queue *fq; 727 struct ipv6hdr *hdr = ipv6_hdr(skb); 728 729 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMREQDS); 730 731 /* Jumbo payload inhibits frag. header */ 732 if (hdr->payload_len==0) { 733 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); 734 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 735 skb_network_header_len(skb)); 736 return -1; 737 } 738 if (!pskb_may_pull(skb, (skb_transport_offset(skb) + 739 sizeof(struct frag_hdr)))) { 740 IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); 741 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 742 skb_network_header_len(skb)); 743 return -1; 744 } 745 746 hdr = ipv6_hdr(skb); 747 fhdr = (struct frag_hdr *)skb_transport_header(skb); 748 749 if (!(fhdr->frag_off & htons(0xFFF9))) { 750 /* It is not a fragmented frame */ 751 skb->transport_header += sizeof(struct frag_hdr); 752 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMOKS); 753 754 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb); 755 return 1; 756 } 757 758 if (atomic_read(&ip6_frag_mem) > sysctl_ip6frag_high_thresh) 759 ip6_evictor(ip6_dst_idev(skb->dst)); 760 761 if ((fq = fq_find(fhdr->identification, &hdr->saddr, &hdr->daddr, 762 ip6_dst_idev(skb->dst))) != NULL) { 763 int ret; 764 765 spin_lock(&fq->q.lock); 766 767 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff); 768 769 spin_unlock(&fq->q.lock); 770 fq_put(fq, NULL); 771 return ret; 772 } 773 774 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_REASMFAILS); 775 kfree_skb(skb); 776 return -1; 777 } 778 779 static struct inet6_protocol frag_protocol = 780 { 781 .handler = ipv6_frag_rcv, 782 .flags = INET6_PROTO_NOPOLICY, 783 }; 784 785 void __init ipv6_frag_init(void) 786 { 787 if (inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT) < 0) 788 printk(KERN_ERR "ipv6_frag_init: Could not register protocol\n"); 789 790 ip6_frag_hash_rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^ 791 (jiffies ^ (jiffies >> 6))); 792 793 init_timer(&ip6_frag_secret_timer); 794 ip6_frag_secret_timer.function = ip6_frag_secret_rebuild; 795 ip6_frag_secret_timer.expires = jiffies + sysctl_ip6frag_secret_interval; 796 add_timer(&ip6_frag_secret_timer); 797 } 798