1 /* 2 * IPv6 fragment reassembly 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * Based on: net/ipv4/ip_fragment.c 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 /* 17 * Fixes: 18 * Andi Kleen Make it work with multiple hosts. 19 * More RFC compliance. 20 * 21 * Horst von Brand Add missing #include <linux/string.h> 22 * Alexey Kuznetsov SMP races, threading, cleanup. 23 * Patrick McHardy LRU queue of frag heads for evictor. 24 * Mitsuru KANDA @USAGI Register inet6_protocol{}. 25 * David Stevens and 26 * YOSHIFUJI,H. @USAGI Always remove fragment header to 27 * calculate ICV correctly. 28 */ 29 30 #define pr_fmt(fmt) "IPv6: " fmt 31 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 #include <linux/skbuff.h> 47 #include <linux/slab.h> 48 #include <linux/export.h> 49 50 #include <net/sock.h> 51 #include <net/snmp.h> 52 53 #include <net/ipv6.h> 54 #include <net/ip6_route.h> 55 #include <net/protocol.h> 56 #include <net/transp_v6.h> 57 #include <net/rawv6.h> 58 #include <net/ndisc.h> 59 #include <net/addrconf.h> 60 #include <net/inet_frag.h> 61 #include <net/inet_ecn.h> 62 63 static const char ip6_frag_cache_name[] = "ip6-frags"; 64 65 static u8 ip6_frag_ecn(const struct ipv6hdr *ipv6h) 66 { 67 return 1 << (ipv6_get_dsfield(ipv6h) & INET_ECN_MASK); 68 } 69 70 static struct inet_frags ip6_frags; 71 72 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 73 struct net_device *dev); 74 75 void ip6_frag_init(struct inet_frag_queue *q, const void *a) 76 { 77 struct frag_queue *fq = container_of(q, struct frag_queue, q); 78 const struct frag_v6_compare_key *key = a; 79 80 q->key.v6 = *key; 81 fq->ecn = 0; 82 } 83 EXPORT_SYMBOL(ip6_frag_init); 84 85 void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq) 86 { 87 struct net_device *dev = NULL; 88 struct sk_buff *head; 89 90 rcu_read_lock(); 91 spin_lock(&fq->q.lock); 92 93 if (fq->q.flags & INET_FRAG_COMPLETE) 94 goto out; 95 96 inet_frag_kill(&fq->q); 97 98 dev = dev_get_by_index_rcu(net, fq->iif); 99 if (!dev) 100 goto out; 101 102 __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 103 __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT); 104 105 /* Don't send error if the first segment did not arrive. */ 106 head = fq->q.fragments; 107 if (!(fq->q.flags & INET_FRAG_FIRST_IN) || !head) 108 goto out; 109 110 /* But use as source device on which LAST ARRIVED 111 * segment was received. And do not use fq->dev 112 * pointer directly, device might already disappeared. 113 */ 114 head->dev = dev; 115 skb_get(head); 116 spin_unlock(&fq->q.lock); 117 118 icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0); 119 kfree_skb(head); 120 goto out_rcu_unlock; 121 122 out: 123 spin_unlock(&fq->q.lock); 124 out_rcu_unlock: 125 rcu_read_unlock(); 126 inet_frag_put(&fq->q); 127 } 128 EXPORT_SYMBOL(ip6_expire_frag_queue); 129 130 static void ip6_frag_expire(struct timer_list *t) 131 { 132 struct inet_frag_queue *frag = from_timer(frag, t, timer); 133 struct frag_queue *fq; 134 struct net *net; 135 136 fq = container_of(frag, struct frag_queue, q); 137 net = container_of(fq->q.net, struct net, ipv6.frags); 138 139 ip6_expire_frag_queue(net, fq); 140 } 141 142 static struct frag_queue * 143 fq_find(struct net *net, __be32 id, const struct ipv6hdr *hdr, int iif) 144 { 145 struct frag_v6_compare_key key = { 146 .id = id, 147 .saddr = hdr->saddr, 148 .daddr = hdr->daddr, 149 .user = IP6_DEFRAG_LOCAL_DELIVER, 150 .iif = iif, 151 }; 152 struct inet_frag_queue *q; 153 154 if (!(ipv6_addr_type(&hdr->daddr) & (IPV6_ADDR_MULTICAST | 155 IPV6_ADDR_LINKLOCAL))) 156 key.iif = 0; 157 158 q = inet_frag_find(&net->ipv6.frags, &key); 159 if (!q) 160 return NULL; 161 162 return container_of(q, struct frag_queue, q); 163 } 164 165 static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb, 166 struct frag_hdr *fhdr, int nhoff, 167 u32 *prob_offset) 168 { 169 struct sk_buff *prev, *next; 170 struct net_device *dev; 171 int offset, end, fragsize; 172 struct net *net = dev_net(skb_dst(skb)->dev); 173 u8 ecn; 174 175 if (fq->q.flags & INET_FRAG_COMPLETE) 176 goto err; 177 178 offset = ntohs(fhdr->frag_off) & ~0x7; 179 end = offset + (ntohs(ipv6_hdr(skb)->payload_len) - 180 ((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1))); 181 182 if ((unsigned int)end > IPV6_MAXPLEN) { 183 *prob_offset = (u8 *)&fhdr->frag_off - skb_network_header(skb); 184 return -1; 185 } 186 187 ecn = ip6_frag_ecn(ipv6_hdr(skb)); 188 189 if (skb->ip_summed == CHECKSUM_COMPLETE) { 190 const unsigned char *nh = skb_network_header(skb); 191 skb->csum = csum_sub(skb->csum, 192 csum_partial(nh, (u8 *)(fhdr + 1) - nh, 193 0)); 194 } 195 196 /* Is this the final fragment? */ 197 if (!(fhdr->frag_off & htons(IP6_MF))) { 198 /* If we already have some bits beyond end 199 * or have different end, the segment is corrupted. 200 */ 201 if (end < fq->q.len || 202 ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len)) 203 goto err; 204 fq->q.flags |= INET_FRAG_LAST_IN; 205 fq->q.len = end; 206 } else { 207 /* Check if the fragment is rounded to 8 bytes. 208 * Required by the RFC. 209 */ 210 if (end & 0x7) { 211 /* RFC2460 says always send parameter problem in 212 * this case. -DaveM 213 */ 214 *prob_offset = offsetof(struct ipv6hdr, payload_len); 215 return -1; 216 } 217 if (end > fq->q.len) { 218 /* Some bits beyond end -> corruption. */ 219 if (fq->q.flags & INET_FRAG_LAST_IN) 220 goto err; 221 fq->q.len = end; 222 } 223 } 224 225 if (end == offset) 226 goto err; 227 228 /* Point into the IP datagram 'data' part. */ 229 if (!pskb_pull(skb, (u8 *) (fhdr + 1) - skb->data)) 230 goto err; 231 232 if (pskb_trim_rcsum(skb, end - offset)) 233 goto err; 234 235 /* Find out which fragments are in front and at the back of us 236 * in the chain of fragments so far. We must know where to put 237 * this fragment, right? 238 */ 239 prev = fq->q.fragments_tail; 240 if (!prev || prev->ip_defrag_offset < offset) { 241 next = NULL; 242 goto found; 243 } 244 prev = NULL; 245 for (next = fq->q.fragments; next != NULL; next = next->next) { 246 if (next->ip_defrag_offset >= offset) 247 break; /* bingo! */ 248 prev = next; 249 } 250 251 found: 252 /* RFC5722, Section 4, amended by Errata ID : 3089 253 * When reassembling an IPv6 datagram, if 254 * one or more its constituent fragments is determined to be an 255 * overlapping fragment, the entire datagram (and any constituent 256 * fragments) MUST be silently discarded. 257 */ 258 259 /* Check for overlap with preceding fragment. */ 260 if (prev && 261 (prev->ip_defrag_offset + prev->len) > offset) 262 goto discard_fq; 263 264 /* Look for overlap with succeeding segment. */ 265 if (next && next->ip_defrag_offset < end) 266 goto discard_fq; 267 268 /* Note : skb->ip_defrag_offset and skb->dev share the same location */ 269 dev = skb->dev; 270 if (dev) 271 fq->iif = dev->ifindex; 272 /* Makes sure compiler wont do silly aliasing games */ 273 barrier(); 274 skb->ip_defrag_offset = offset; 275 276 /* Insert this fragment in the chain of fragments. */ 277 skb->next = next; 278 if (!next) 279 fq->q.fragments_tail = skb; 280 if (prev) 281 prev->next = skb; 282 else 283 fq->q.fragments = skb; 284 285 fq->q.stamp = skb->tstamp; 286 fq->q.meat += skb->len; 287 fq->ecn |= ecn; 288 add_frag_mem_limit(fq->q.net, skb->truesize); 289 290 fragsize = -skb_network_offset(skb) + skb->len; 291 if (fragsize > fq->q.max_size) 292 fq->q.max_size = fragsize; 293 294 /* The first fragment. 295 * nhoffset is obtained from the first fragment, of course. 296 */ 297 if (offset == 0) { 298 fq->nhoffset = nhoff; 299 fq->q.flags |= INET_FRAG_FIRST_IN; 300 } 301 302 if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 303 fq->q.meat == fq->q.len) { 304 int res; 305 unsigned long orefdst = skb->_skb_refdst; 306 307 skb->_skb_refdst = 0UL; 308 res = ip6_frag_reasm(fq, prev, dev); 309 skb->_skb_refdst = orefdst; 310 return res; 311 } 312 313 skb_dst_drop(skb); 314 return -1; 315 316 discard_fq: 317 inet_frag_kill(&fq->q); 318 err: 319 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 320 IPSTATS_MIB_REASMFAILS); 321 kfree_skb(skb); 322 return -1; 323 } 324 325 /* 326 * Check if this packet is complete. 327 * Returns NULL on failure by any reason, and pointer 328 * to current nexthdr field in reassembled frame. 329 * 330 * It is called with locked fq, and caller must check that 331 * queue is eligible for reassembly i.e. it is not COMPLETE, 332 * the last and the first frames arrived and all the bits are here. 333 */ 334 static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev, 335 struct net_device *dev) 336 { 337 struct net *net = container_of(fq->q.net, struct net, ipv6.frags); 338 struct sk_buff *fp, *head = fq->q.fragments; 339 int payload_len; 340 unsigned int nhoff; 341 int sum_truesize; 342 u8 ecn; 343 344 inet_frag_kill(&fq->q); 345 346 ecn = ip_frag_ecn_table[fq->ecn]; 347 if (unlikely(ecn == 0xff)) 348 goto out_fail; 349 350 /* Make the one we just received the head. */ 351 if (prev) { 352 head = prev->next; 353 fp = skb_clone(head, GFP_ATOMIC); 354 355 if (!fp) 356 goto out_oom; 357 358 fp->next = head->next; 359 if (!fp->next) 360 fq->q.fragments_tail = fp; 361 prev->next = fp; 362 363 skb_morph(head, fq->q.fragments); 364 head->next = fq->q.fragments->next; 365 366 consume_skb(fq->q.fragments); 367 fq->q.fragments = head; 368 } 369 370 WARN_ON(head == NULL); 371 WARN_ON(head->ip_defrag_offset != 0); 372 373 /* Unfragmented part is taken from the first segment. */ 374 payload_len = ((head->data - skb_network_header(head)) - 375 sizeof(struct ipv6hdr) + fq->q.len - 376 sizeof(struct frag_hdr)); 377 if (payload_len > IPV6_MAXPLEN) 378 goto out_oversize; 379 380 /* Head of list must not be cloned. */ 381 if (skb_unclone(head, GFP_ATOMIC)) 382 goto out_oom; 383 384 /* If the first fragment is fragmented itself, we split 385 * it to two chunks: the first with data and paged part 386 * and the second, holding only fragments. */ 387 if (skb_has_frag_list(head)) { 388 struct sk_buff *clone; 389 int i, plen = 0; 390 391 clone = alloc_skb(0, GFP_ATOMIC); 392 if (!clone) 393 goto out_oom; 394 clone->next = head->next; 395 head->next = clone; 396 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 397 skb_frag_list_init(head); 398 for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 399 plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 400 clone->len = clone->data_len = head->data_len - plen; 401 head->data_len -= clone->len; 402 head->len -= clone->len; 403 clone->csum = 0; 404 clone->ip_summed = head->ip_summed; 405 add_frag_mem_limit(fq->q.net, clone->truesize); 406 } 407 408 /* We have to remove fragment header from datagram and to relocate 409 * header in order to calculate ICV correctly. */ 410 nhoff = fq->nhoffset; 411 skb_network_header(head)[nhoff] = skb_transport_header(head)[0]; 412 memmove(head->head + sizeof(struct frag_hdr), head->head, 413 (head->data - head->head) - sizeof(struct frag_hdr)); 414 if (skb_mac_header_was_set(head)) 415 head->mac_header += sizeof(struct frag_hdr); 416 head->network_header += sizeof(struct frag_hdr); 417 418 skb_reset_transport_header(head); 419 skb_push(head, head->data - skb_network_header(head)); 420 421 sum_truesize = head->truesize; 422 for (fp = head->next; fp;) { 423 bool headstolen; 424 int delta; 425 struct sk_buff *next = fp->next; 426 427 sum_truesize += fp->truesize; 428 if (head->ip_summed != fp->ip_summed) 429 head->ip_summed = CHECKSUM_NONE; 430 else if (head->ip_summed == CHECKSUM_COMPLETE) 431 head->csum = csum_add(head->csum, fp->csum); 432 433 if (skb_try_coalesce(head, fp, &headstolen, &delta)) { 434 kfree_skb_partial(fp, headstolen); 435 } else { 436 if (!skb_shinfo(head)->frag_list) 437 skb_shinfo(head)->frag_list = fp; 438 head->data_len += fp->len; 439 head->len += fp->len; 440 head->truesize += fp->truesize; 441 } 442 fp = next; 443 } 444 sub_frag_mem_limit(fq->q.net, sum_truesize); 445 446 head->next = NULL; 447 head->dev = dev; 448 head->tstamp = fq->q.stamp; 449 ipv6_hdr(head)->payload_len = htons(payload_len); 450 ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn); 451 IP6CB(head)->nhoff = nhoff; 452 IP6CB(head)->flags |= IP6SKB_FRAGMENTED; 453 IP6CB(head)->frag_max_size = fq->q.max_size; 454 455 /* Yes, and fold redundant checksum back. 8) */ 456 skb_postpush_rcsum(head, skb_network_header(head), 457 skb_network_header_len(head)); 458 459 rcu_read_lock(); 460 __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS); 461 rcu_read_unlock(); 462 fq->q.fragments = NULL; 463 fq->q.fragments_tail = NULL; 464 return 1; 465 466 out_oversize: 467 net_dbg_ratelimited("ip6_frag_reasm: payload len = %d\n", payload_len); 468 goto out_fail; 469 out_oom: 470 net_dbg_ratelimited("ip6_frag_reasm: no memory for reassembly\n"); 471 out_fail: 472 rcu_read_lock(); 473 __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS); 474 rcu_read_unlock(); 475 return -1; 476 } 477 478 static int ipv6_frag_rcv(struct sk_buff *skb) 479 { 480 struct frag_hdr *fhdr; 481 struct frag_queue *fq; 482 const struct ipv6hdr *hdr = ipv6_hdr(skb); 483 struct net *net = dev_net(skb_dst(skb)->dev); 484 int iif; 485 486 if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED) 487 goto fail_hdr; 488 489 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS); 490 491 /* Jumbo payload inhibits frag. header */ 492 if (hdr->payload_len == 0) 493 goto fail_hdr; 494 495 if (!pskb_may_pull(skb, (skb_transport_offset(skb) + 496 sizeof(struct frag_hdr)))) 497 goto fail_hdr; 498 499 hdr = ipv6_hdr(skb); 500 fhdr = (struct frag_hdr *)skb_transport_header(skb); 501 502 if (!(fhdr->frag_off & htons(0xFFF9))) { 503 /* It is not a fragmented frame */ 504 skb->transport_header += sizeof(struct frag_hdr); 505 __IP6_INC_STATS(net, 506 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS); 507 508 IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb); 509 IP6CB(skb)->flags |= IP6SKB_FRAGMENTED; 510 return 1; 511 } 512 513 iif = skb->dev ? skb->dev->ifindex : 0; 514 fq = fq_find(net, fhdr->identification, hdr, iif); 515 if (fq) { 516 u32 prob_offset = 0; 517 int ret; 518 519 spin_lock(&fq->q.lock); 520 521 fq->iif = iif; 522 ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff, 523 &prob_offset); 524 525 spin_unlock(&fq->q.lock); 526 inet_frag_put(&fq->q); 527 if (prob_offset) { 528 __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), 529 IPSTATS_MIB_INHDRERRORS); 530 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, prob_offset); 531 } 532 return ret; 533 } 534 535 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMFAILS); 536 kfree_skb(skb); 537 return -1; 538 539 fail_hdr: 540 __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), 541 IPSTATS_MIB_INHDRERRORS); 542 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb)); 543 return -1; 544 } 545 546 static const struct inet6_protocol frag_protocol = { 547 .handler = ipv6_frag_rcv, 548 .flags = INET6_PROTO_NOPOLICY, 549 }; 550 551 #ifdef CONFIG_SYSCTL 552 553 static struct ctl_table ip6_frags_ns_ctl_table[] = { 554 { 555 .procname = "ip6frag_high_thresh", 556 .data = &init_net.ipv6.frags.high_thresh, 557 .maxlen = sizeof(unsigned long), 558 .mode = 0644, 559 .proc_handler = proc_doulongvec_minmax, 560 .extra1 = &init_net.ipv6.frags.low_thresh 561 }, 562 { 563 .procname = "ip6frag_low_thresh", 564 .data = &init_net.ipv6.frags.low_thresh, 565 .maxlen = sizeof(unsigned long), 566 .mode = 0644, 567 .proc_handler = proc_doulongvec_minmax, 568 .extra2 = &init_net.ipv6.frags.high_thresh 569 }, 570 { 571 .procname = "ip6frag_time", 572 .data = &init_net.ipv6.frags.timeout, 573 .maxlen = sizeof(int), 574 .mode = 0644, 575 .proc_handler = proc_dointvec_jiffies, 576 }, 577 { } 578 }; 579 580 /* secret interval has been deprecated */ 581 static int ip6_frags_secret_interval_unused; 582 static struct ctl_table ip6_frags_ctl_table[] = { 583 { 584 .procname = "ip6frag_secret_interval", 585 .data = &ip6_frags_secret_interval_unused, 586 .maxlen = sizeof(int), 587 .mode = 0644, 588 .proc_handler = proc_dointvec_jiffies, 589 }, 590 { } 591 }; 592 593 static int __net_init ip6_frags_ns_sysctl_register(struct net *net) 594 { 595 struct ctl_table *table; 596 struct ctl_table_header *hdr; 597 598 table = ip6_frags_ns_ctl_table; 599 if (!net_eq(net, &init_net)) { 600 table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL); 601 if (!table) 602 goto err_alloc; 603 604 table[0].data = &net->ipv6.frags.high_thresh; 605 table[0].extra1 = &net->ipv6.frags.low_thresh; 606 table[0].extra2 = &init_net.ipv6.frags.high_thresh; 607 table[1].data = &net->ipv6.frags.low_thresh; 608 table[1].extra2 = &net->ipv6.frags.high_thresh; 609 table[2].data = &net->ipv6.frags.timeout; 610 } 611 612 hdr = register_net_sysctl(net, "net/ipv6", table); 613 if (!hdr) 614 goto err_reg; 615 616 net->ipv6.sysctl.frags_hdr = hdr; 617 return 0; 618 619 err_reg: 620 if (!net_eq(net, &init_net)) 621 kfree(table); 622 err_alloc: 623 return -ENOMEM; 624 } 625 626 static void __net_exit ip6_frags_ns_sysctl_unregister(struct net *net) 627 { 628 struct ctl_table *table; 629 630 table = net->ipv6.sysctl.frags_hdr->ctl_table_arg; 631 unregister_net_sysctl_table(net->ipv6.sysctl.frags_hdr); 632 if (!net_eq(net, &init_net)) 633 kfree(table); 634 } 635 636 static struct ctl_table_header *ip6_ctl_header; 637 638 static int ip6_frags_sysctl_register(void) 639 { 640 ip6_ctl_header = register_net_sysctl(&init_net, "net/ipv6", 641 ip6_frags_ctl_table); 642 return ip6_ctl_header == NULL ? -ENOMEM : 0; 643 } 644 645 static void ip6_frags_sysctl_unregister(void) 646 { 647 unregister_net_sysctl_table(ip6_ctl_header); 648 } 649 #else 650 static int ip6_frags_ns_sysctl_register(struct net *net) 651 { 652 return 0; 653 } 654 655 static void ip6_frags_ns_sysctl_unregister(struct net *net) 656 { 657 } 658 659 static int ip6_frags_sysctl_register(void) 660 { 661 return 0; 662 } 663 664 static void ip6_frags_sysctl_unregister(void) 665 { 666 } 667 #endif 668 669 static int __net_init ipv6_frags_init_net(struct net *net) 670 { 671 int res; 672 673 net->ipv6.frags.high_thresh = IPV6_FRAG_HIGH_THRESH; 674 net->ipv6.frags.low_thresh = IPV6_FRAG_LOW_THRESH; 675 net->ipv6.frags.timeout = IPV6_FRAG_TIMEOUT; 676 net->ipv6.frags.f = &ip6_frags; 677 678 res = inet_frags_init_net(&net->ipv6.frags); 679 if (res < 0) 680 return res; 681 682 res = ip6_frags_ns_sysctl_register(net); 683 if (res < 0) 684 inet_frags_exit_net(&net->ipv6.frags); 685 return res; 686 } 687 688 static void __net_exit ipv6_frags_exit_net(struct net *net) 689 { 690 ip6_frags_ns_sysctl_unregister(net); 691 inet_frags_exit_net(&net->ipv6.frags); 692 } 693 694 static struct pernet_operations ip6_frags_ops = { 695 .init = ipv6_frags_init_net, 696 .exit = ipv6_frags_exit_net, 697 }; 698 699 static u32 ip6_key_hashfn(const void *data, u32 len, u32 seed) 700 { 701 return jhash2(data, 702 sizeof(struct frag_v6_compare_key) / sizeof(u32), seed); 703 } 704 705 static u32 ip6_obj_hashfn(const void *data, u32 len, u32 seed) 706 { 707 const struct inet_frag_queue *fq = data; 708 709 return jhash2((const u32 *)&fq->key.v6, 710 sizeof(struct frag_v6_compare_key) / sizeof(u32), seed); 711 } 712 713 static int ip6_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr) 714 { 715 const struct frag_v6_compare_key *key = arg->key; 716 const struct inet_frag_queue *fq = ptr; 717 718 return !!memcmp(&fq->key, key, sizeof(*key)); 719 } 720 721 const struct rhashtable_params ip6_rhash_params = { 722 .head_offset = offsetof(struct inet_frag_queue, node), 723 .hashfn = ip6_key_hashfn, 724 .obj_hashfn = ip6_obj_hashfn, 725 .obj_cmpfn = ip6_obj_cmpfn, 726 .automatic_shrinking = true, 727 }; 728 EXPORT_SYMBOL(ip6_rhash_params); 729 730 int __init ipv6_frag_init(void) 731 { 732 int ret; 733 734 ip6_frags.constructor = ip6_frag_init; 735 ip6_frags.destructor = NULL; 736 ip6_frags.qsize = sizeof(struct frag_queue); 737 ip6_frags.frag_expire = ip6_frag_expire; 738 ip6_frags.frags_cache_name = ip6_frag_cache_name; 739 ip6_frags.rhash_params = ip6_rhash_params; 740 ret = inet_frags_init(&ip6_frags); 741 if (ret) 742 goto out; 743 744 ret = inet6_add_protocol(&frag_protocol, IPPROTO_FRAGMENT); 745 if (ret) 746 goto err_protocol; 747 748 ret = ip6_frags_sysctl_register(); 749 if (ret) 750 goto err_sysctl; 751 752 ret = register_pernet_subsys(&ip6_frags_ops); 753 if (ret) 754 goto err_pernet; 755 756 out: 757 return ret; 758 759 err_pernet: 760 ip6_frags_sysctl_unregister(); 761 err_sysctl: 762 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT); 763 err_protocol: 764 inet_frags_fini(&ip6_frags); 765 goto out; 766 } 767 768 void ipv6_frag_exit(void) 769 { 770 inet_frags_fini(&ip6_frags); 771 ip6_frags_sysctl_unregister(); 772 unregister_pernet_subsys(&ip6_frags_ops); 773 inet6_del_protocol(&frag_protocol, IPPROTO_FRAGMENT); 774 } 775