1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * The IP fragmentation functionality. 8 * 9 * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> 10 * Alan Cox <alan@lxorguk.ukuu.org.uk> 11 * 12 * Fixes: 13 * Alan Cox : Split from ip.c , see ip_input.c for history. 14 * David S. Miller : Begin massive cleanup... 15 * Andi Kleen : Add sysctls. 16 * xxxx : Overlapfrag bug. 17 * Ultima : ip_expire() kernel panic. 18 * Bill Hawes : Frag accounting and evictor fixes. 19 * John McDonald : 0 length frag bug. 20 * Alexey Kuznetsov: SMP races, threading, cleanup. 21 * Patrick McHardy : LRU queue of frag heads for evictor. 22 */ 23 24 #define pr_fmt(fmt) "IPv4: " fmt 25 26 #include <linux/compiler.h> 27 #include <linux/module.h> 28 #include <linux/types.h> 29 #include <linux/mm.h> 30 #include <linux/jiffies.h> 31 #include <linux/skbuff.h> 32 #include <linux/list.h> 33 #include <linux/ip.h> 34 #include <linux/icmp.h> 35 #include <linux/netdevice.h> 36 #include <linux/jhash.h> 37 #include <linux/random.h> 38 #include <linux/slab.h> 39 #include <net/route.h> 40 #include <net/dst.h> 41 #include <net/sock.h> 42 #include <net/ip.h> 43 #include <net/icmp.h> 44 #include <net/checksum.h> 45 #include <net/inetpeer.h> 46 #include <net/inet_frag.h> 47 #include <linux/tcp.h> 48 #include <linux/udp.h> 49 #include <linux/inet.h> 50 #include <linux/netfilter_ipv4.h> 51 #include <net/inet_ecn.h> 52 #include <net/l3mdev.h> 53 54 /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6 55 * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c 56 * as well. Or notify me, at least. --ANK 57 */ 58 static const char ip_frag_cache_name[] = "ip4-frags"; 59 60 /* Describe an entry in the "incomplete datagrams" queue. */ 61 struct ipq { 62 struct inet_frag_queue q; 63 64 u8 ecn; /* RFC3168 support */ 65 u16 max_df_size; /* largest frag with DF set seen */ 66 int iif; 67 unsigned int rid; 68 struct inet_peer *peer; 69 }; 70 71 static u8 ip4_frag_ecn(u8 tos) 72 { 73 return 1 << (tos & INET_ECN_MASK); 74 } 75 76 static struct inet_frags ip4_frags; 77 78 static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb, 79 struct sk_buff *prev_tail, struct net_device *dev); 80 81 82 static void ip4_frag_init(struct inet_frag_queue *q, const void *a) 83 { 84 struct ipq *qp = container_of(q, struct ipq, q); 85 struct net *net = q->fqdir->net; 86 87 const struct frag_v4_compare_key *key = a; 88 89 q->key.v4 = *key; 90 qp->ecn = 0; 91 qp->peer = q->fqdir->max_dist ? 92 inet_getpeer_v4(net->ipv4.peers, key->saddr, key->vif, 1) : 93 NULL; 94 } 95 96 static void ip4_frag_free(struct inet_frag_queue *q) 97 { 98 struct ipq *qp; 99 100 qp = container_of(q, struct ipq, q); 101 if (qp->peer) 102 inet_putpeer(qp->peer); 103 } 104 105 106 /* Destruction primitives. */ 107 108 static void ipq_put(struct ipq *ipq) 109 { 110 inet_frag_put(&ipq->q); 111 } 112 113 /* Kill ipq entry. It is not destroyed immediately, 114 * because caller (and someone more) holds reference count. 115 */ 116 static void ipq_kill(struct ipq *ipq) 117 { 118 inet_frag_kill(&ipq->q); 119 } 120 121 static bool frag_expire_skip_icmp(u32 user) 122 { 123 return user == IP_DEFRAG_AF_PACKET || 124 ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_IN, 125 __IP_DEFRAG_CONNTRACK_IN_END) || 126 ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_BRIDGE_IN, 127 __IP_DEFRAG_CONNTRACK_BRIDGE_IN); 128 } 129 130 /* 131 * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 132 */ 133 static void ip_expire(struct timer_list *t) 134 { 135 struct inet_frag_queue *frag = from_timer(frag, t, timer); 136 const struct iphdr *iph; 137 struct sk_buff *head = NULL; 138 struct net *net; 139 struct ipq *qp; 140 int err; 141 142 qp = container_of(frag, struct ipq, q); 143 net = qp->q.fqdir->net; 144 145 rcu_read_lock(); 146 147 /* Paired with WRITE_ONCE() in fqdir_pre_exit(). */ 148 if (READ_ONCE(qp->q.fqdir->dead)) 149 goto out_rcu_unlock; 150 151 spin_lock(&qp->q.lock); 152 153 if (qp->q.flags & INET_FRAG_COMPLETE) 154 goto out; 155 156 qp->q.flags |= INET_FRAG_DROP; 157 ipq_kill(qp); 158 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 159 __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT); 160 161 if (!(qp->q.flags & INET_FRAG_FIRST_IN)) 162 goto out; 163 164 /* sk_buff::dev and sk_buff::rbnode are unionized. So we 165 * pull the head out of the tree in order to be able to 166 * deal with head->dev. 167 */ 168 head = inet_frag_pull_head(&qp->q); 169 if (!head) 170 goto out; 171 head->dev = dev_get_by_index_rcu(net, qp->iif); 172 if (!head->dev) 173 goto out; 174 175 176 /* skb has no dst, perform route lookup again */ 177 iph = ip_hdr(head); 178 err = ip_route_input_noref(head, iph->daddr, iph->saddr, 179 iph->tos, head->dev); 180 if (err) 181 goto out; 182 183 /* Only an end host needs to send an ICMP 184 * "Fragment Reassembly Timeout" message, per RFC792. 185 */ 186 if (frag_expire_skip_icmp(qp->q.key.v4.user) && 187 (skb_rtable(head)->rt_type != RTN_LOCAL)) 188 goto out; 189 190 spin_unlock(&qp->q.lock); 191 icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 192 goto out_rcu_unlock; 193 194 out: 195 spin_unlock(&qp->q.lock); 196 out_rcu_unlock: 197 rcu_read_unlock(); 198 kfree_skb_reason(head, SKB_DROP_REASON_FRAG_REASM_TIMEOUT); 199 ipq_put(qp); 200 } 201 202 /* Find the correct entry in the "incomplete datagrams" queue for 203 * this IP datagram, and create new one, if nothing is found. 204 */ 205 static struct ipq *ip_find(struct net *net, struct iphdr *iph, 206 u32 user, int vif) 207 { 208 struct frag_v4_compare_key key = { 209 .saddr = iph->saddr, 210 .daddr = iph->daddr, 211 .user = user, 212 .vif = vif, 213 .id = iph->id, 214 .protocol = iph->protocol, 215 }; 216 struct inet_frag_queue *q; 217 218 q = inet_frag_find(net->ipv4.fqdir, &key); 219 if (!q) 220 return NULL; 221 222 return container_of(q, struct ipq, q); 223 } 224 225 /* Is the fragment too far ahead to be part of ipq? */ 226 static int ip_frag_too_far(struct ipq *qp) 227 { 228 struct inet_peer *peer = qp->peer; 229 unsigned int max = qp->q.fqdir->max_dist; 230 unsigned int start, end; 231 232 int rc; 233 234 if (!peer || !max) 235 return 0; 236 237 start = qp->rid; 238 end = atomic_inc_return(&peer->rid); 239 qp->rid = end; 240 241 rc = qp->q.fragments_tail && (end - start) > max; 242 243 if (rc) 244 __IP_INC_STATS(qp->q.fqdir->net, IPSTATS_MIB_REASMFAILS); 245 246 return rc; 247 } 248 249 static int ip_frag_reinit(struct ipq *qp) 250 { 251 unsigned int sum_truesize = 0; 252 253 if (!mod_timer(&qp->q.timer, jiffies + qp->q.fqdir->timeout)) { 254 refcount_inc(&qp->q.refcnt); 255 return -ETIMEDOUT; 256 } 257 258 sum_truesize = inet_frag_rbtree_purge(&qp->q.rb_fragments, 259 SKB_DROP_REASON_FRAG_TOO_FAR); 260 sub_frag_mem_limit(qp->q.fqdir, sum_truesize); 261 262 qp->q.flags = 0; 263 qp->q.len = 0; 264 qp->q.meat = 0; 265 qp->q.rb_fragments = RB_ROOT; 266 qp->q.fragments_tail = NULL; 267 qp->q.last_run_head = NULL; 268 qp->iif = 0; 269 qp->ecn = 0; 270 271 return 0; 272 } 273 274 /* Add new segment to existing queue. */ 275 static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 276 { 277 struct net *net = qp->q.fqdir->net; 278 int ihl, end, flags, offset; 279 struct sk_buff *prev_tail; 280 struct net_device *dev; 281 unsigned int fragsize; 282 int err = -ENOENT; 283 SKB_DR(reason); 284 u8 ecn; 285 286 /* If reassembly is already done, @skb must be a duplicate frag. */ 287 if (qp->q.flags & INET_FRAG_COMPLETE) { 288 SKB_DR_SET(reason, DUP_FRAG); 289 goto err; 290 } 291 292 if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 293 unlikely(ip_frag_too_far(qp)) && 294 unlikely(err = ip_frag_reinit(qp))) { 295 ipq_kill(qp); 296 goto err; 297 } 298 299 ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 300 offset = ntohs(ip_hdr(skb)->frag_off); 301 flags = offset & ~IP_OFFSET; 302 offset &= IP_OFFSET; 303 offset <<= 3; /* offset is in 8-byte chunks */ 304 ihl = ip_hdrlen(skb); 305 306 /* Determine the position of this fragment. */ 307 end = offset + skb->len - skb_network_offset(skb) - ihl; 308 err = -EINVAL; 309 310 /* Is this the final fragment? */ 311 if ((flags & IP_MF) == 0) { 312 /* If we already have some bits beyond end 313 * or have different end, the segment is corrupted. 314 */ 315 if (end < qp->q.len || 316 ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len)) 317 goto discard_qp; 318 qp->q.flags |= INET_FRAG_LAST_IN; 319 qp->q.len = end; 320 } else { 321 if (end&7) { 322 end &= ~7; 323 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 324 skb->ip_summed = CHECKSUM_NONE; 325 } 326 if (end > qp->q.len) { 327 /* Some bits beyond end -> corruption. */ 328 if (qp->q.flags & INET_FRAG_LAST_IN) 329 goto discard_qp; 330 qp->q.len = end; 331 } 332 } 333 if (end == offset) 334 goto discard_qp; 335 336 err = -ENOMEM; 337 if (!pskb_pull(skb, skb_network_offset(skb) + ihl)) 338 goto discard_qp; 339 340 err = pskb_trim_rcsum(skb, end - offset); 341 if (err) 342 goto discard_qp; 343 344 /* Note : skb->rbnode and skb->dev share the same location. */ 345 dev = skb->dev; 346 /* Makes sure compiler wont do silly aliasing games */ 347 barrier(); 348 349 prev_tail = qp->q.fragments_tail; 350 err = inet_frag_queue_insert(&qp->q, skb, offset, end); 351 if (err) 352 goto insert_error; 353 354 if (dev) 355 qp->iif = dev->ifindex; 356 357 qp->q.stamp = skb->tstamp; 358 qp->q.mono_delivery_time = skb->mono_delivery_time; 359 qp->q.meat += skb->len; 360 qp->ecn |= ecn; 361 add_frag_mem_limit(qp->q.fqdir, skb->truesize); 362 if (offset == 0) 363 qp->q.flags |= INET_FRAG_FIRST_IN; 364 365 fragsize = skb->len + ihl; 366 367 if (fragsize > qp->q.max_size) 368 qp->q.max_size = fragsize; 369 370 if (ip_hdr(skb)->frag_off & htons(IP_DF) && 371 fragsize > qp->max_df_size) 372 qp->max_df_size = fragsize; 373 374 if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 375 qp->q.meat == qp->q.len) { 376 unsigned long orefdst = skb->_skb_refdst; 377 378 skb->_skb_refdst = 0UL; 379 err = ip_frag_reasm(qp, skb, prev_tail, dev); 380 skb->_skb_refdst = orefdst; 381 if (err) 382 inet_frag_kill(&qp->q); 383 return err; 384 } 385 386 skb_dst_drop(skb); 387 skb_orphan(skb); 388 return -EINPROGRESS; 389 390 insert_error: 391 if (err == IPFRAG_DUP) { 392 SKB_DR_SET(reason, DUP_FRAG); 393 err = -EINVAL; 394 goto err; 395 } 396 err = -EINVAL; 397 __IP_INC_STATS(net, IPSTATS_MIB_REASM_OVERLAPS); 398 discard_qp: 399 inet_frag_kill(&qp->q); 400 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 401 err: 402 kfree_skb_reason(skb, reason); 403 return err; 404 } 405 406 static bool ip_frag_coalesce_ok(const struct ipq *qp) 407 { 408 return qp->q.key.v4.user == IP_DEFRAG_LOCAL_DELIVER; 409 } 410 411 /* Build a new IP datagram from all its fragments. */ 412 static int ip_frag_reasm(struct ipq *qp, struct sk_buff *skb, 413 struct sk_buff *prev_tail, struct net_device *dev) 414 { 415 struct net *net = qp->q.fqdir->net; 416 struct iphdr *iph; 417 void *reasm_data; 418 int len, err; 419 u8 ecn; 420 421 ipq_kill(qp); 422 423 ecn = ip_frag_ecn_table[qp->ecn]; 424 if (unlikely(ecn == 0xff)) { 425 err = -EINVAL; 426 goto out_fail; 427 } 428 429 /* Make the one we just received the head. */ 430 reasm_data = inet_frag_reasm_prepare(&qp->q, skb, prev_tail); 431 if (!reasm_data) 432 goto out_nomem; 433 434 len = ip_hdrlen(skb) + qp->q.len; 435 err = -E2BIG; 436 if (len > 65535) 437 goto out_oversize; 438 439 inet_frag_reasm_finish(&qp->q, skb, reasm_data, 440 ip_frag_coalesce_ok(qp)); 441 442 skb->dev = dev; 443 IPCB(skb)->frag_max_size = max(qp->max_df_size, qp->q.max_size); 444 445 iph = ip_hdr(skb); 446 iph->tot_len = htons(len); 447 iph->tos |= ecn; 448 449 /* When we set IP_DF on a refragmented skb we must also force a 450 * call to ip_fragment to avoid forwarding a DF-skb of size s while 451 * original sender only sent fragments of size f (where f < s). 452 * 453 * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest 454 * frag seen to avoid sending tiny DF-fragments in case skb was built 455 * from one very small df-fragment and one large non-df frag. 456 */ 457 if (qp->max_df_size == qp->q.max_size) { 458 IPCB(skb)->flags |= IPSKB_FRAG_PMTU; 459 iph->frag_off = htons(IP_DF); 460 } else { 461 iph->frag_off = 0; 462 } 463 464 ip_send_check(iph); 465 466 __IP_INC_STATS(net, IPSTATS_MIB_REASMOKS); 467 qp->q.rb_fragments = RB_ROOT; 468 qp->q.fragments_tail = NULL; 469 qp->q.last_run_head = NULL; 470 return 0; 471 472 out_nomem: 473 net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp); 474 err = -ENOMEM; 475 goto out_fail; 476 out_oversize: 477 net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->q.key.v4.saddr); 478 out_fail: 479 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 480 return err; 481 } 482 483 /* Process an incoming IP datagram fragment. */ 484 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user) 485 { 486 struct net_device *dev = skb->dev ? : skb_dst(skb)->dev; 487 int vif = l3mdev_master_ifindex_rcu(dev); 488 struct ipq *qp; 489 490 __IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS); 491 492 /* Lookup (or create) queue header */ 493 qp = ip_find(net, ip_hdr(skb), user, vif); 494 if (qp) { 495 int ret; 496 497 spin_lock(&qp->q.lock); 498 499 ret = ip_frag_queue(qp, skb); 500 501 spin_unlock(&qp->q.lock); 502 ipq_put(qp); 503 return ret; 504 } 505 506 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 507 kfree_skb(skb); 508 return -ENOMEM; 509 } 510 EXPORT_SYMBOL(ip_defrag); 511 512 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user) 513 { 514 struct iphdr iph; 515 int netoff; 516 u32 len; 517 518 if (skb->protocol != htons(ETH_P_IP)) 519 return skb; 520 521 netoff = skb_network_offset(skb); 522 523 if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) 524 return skb; 525 526 if (iph.ihl < 5 || iph.version != 4) 527 return skb; 528 529 len = ntohs(iph.tot_len); 530 if (skb->len < netoff + len || len < (iph.ihl * 4)) 531 return skb; 532 533 if (ip_is_fragment(&iph)) { 534 skb = skb_share_check(skb, GFP_ATOMIC); 535 if (skb) { 536 if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) { 537 kfree_skb(skb); 538 return NULL; 539 } 540 if (pskb_trim_rcsum(skb, netoff + len)) { 541 kfree_skb(skb); 542 return NULL; 543 } 544 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 545 if (ip_defrag(net, skb, user)) 546 return NULL; 547 skb_clear_hash(skb); 548 } 549 } 550 return skb; 551 } 552 EXPORT_SYMBOL(ip_check_defrag); 553 554 #ifdef CONFIG_SYSCTL 555 static int dist_min; 556 557 static struct ctl_table ip4_frags_ns_ctl_table[] = { 558 { 559 .procname = "ipfrag_high_thresh", 560 .maxlen = sizeof(unsigned long), 561 .mode = 0644, 562 .proc_handler = proc_doulongvec_minmax, 563 }, 564 { 565 .procname = "ipfrag_low_thresh", 566 .maxlen = sizeof(unsigned long), 567 .mode = 0644, 568 .proc_handler = proc_doulongvec_minmax, 569 }, 570 { 571 .procname = "ipfrag_time", 572 .maxlen = sizeof(int), 573 .mode = 0644, 574 .proc_handler = proc_dointvec_jiffies, 575 }, 576 { 577 .procname = "ipfrag_max_dist", 578 .maxlen = sizeof(int), 579 .mode = 0644, 580 .proc_handler = proc_dointvec_minmax, 581 .extra1 = &dist_min, 582 }, 583 }; 584 585 /* secret interval has been deprecated */ 586 static int ip4_frags_secret_interval_unused; 587 static struct ctl_table ip4_frags_ctl_table[] = { 588 { 589 .procname = "ipfrag_secret_interval", 590 .data = &ip4_frags_secret_interval_unused, 591 .maxlen = sizeof(int), 592 .mode = 0644, 593 .proc_handler = proc_dointvec_jiffies, 594 }, 595 }; 596 597 static int __net_init ip4_frags_ns_ctl_register(struct net *net) 598 { 599 struct ctl_table *table; 600 struct ctl_table_header *hdr; 601 602 table = ip4_frags_ns_ctl_table; 603 if (!net_eq(net, &init_net)) { 604 table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 605 if (!table) 606 goto err_alloc; 607 608 } 609 table[0].data = &net->ipv4.fqdir->high_thresh; 610 table[0].extra1 = &net->ipv4.fqdir->low_thresh; 611 table[1].data = &net->ipv4.fqdir->low_thresh; 612 table[1].extra2 = &net->ipv4.fqdir->high_thresh; 613 table[2].data = &net->ipv4.fqdir->timeout; 614 table[3].data = &net->ipv4.fqdir->max_dist; 615 616 hdr = register_net_sysctl_sz(net, "net/ipv4", table, 617 ARRAY_SIZE(ip4_frags_ns_ctl_table)); 618 if (!hdr) 619 goto err_reg; 620 621 net->ipv4.frags_hdr = hdr; 622 return 0; 623 624 err_reg: 625 if (!net_eq(net, &init_net)) 626 kfree(table); 627 err_alloc: 628 return -ENOMEM; 629 } 630 631 static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 632 { 633 const struct ctl_table *table; 634 635 table = net->ipv4.frags_hdr->ctl_table_arg; 636 unregister_net_sysctl_table(net->ipv4.frags_hdr); 637 kfree(table); 638 } 639 640 static void __init ip4_frags_ctl_register(void) 641 { 642 register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); 643 } 644 #else 645 static int ip4_frags_ns_ctl_register(struct net *net) 646 { 647 return 0; 648 } 649 650 static void ip4_frags_ns_ctl_unregister(struct net *net) 651 { 652 } 653 654 static void __init ip4_frags_ctl_register(void) 655 { 656 } 657 #endif 658 659 static int __net_init ipv4_frags_init_net(struct net *net) 660 { 661 int res; 662 663 res = fqdir_init(&net->ipv4.fqdir, &ip4_frags, net); 664 if (res < 0) 665 return res; 666 /* Fragment cache limits. 667 * 668 * The fragment memory accounting code, (tries to) account for 669 * the real memory usage, by measuring both the size of frag 670 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) 671 * and the SKB's truesize. 672 * 673 * A 64K fragment consumes 129736 bytes (44*2944)+200 674 * (1500 truesize == 2944, sizeof(struct ipq) == 200) 675 * 676 * We will commit 4MB at one time. Should we cross that limit 677 * we will prune down to 3MB, making room for approx 8 big 64K 678 * fragments 8x128k. 679 */ 680 net->ipv4.fqdir->high_thresh = 4 * 1024 * 1024; 681 net->ipv4.fqdir->low_thresh = 3 * 1024 * 1024; 682 /* 683 * Important NOTE! Fragment queue must be destroyed before MSL expires. 684 * RFC791 is wrong proposing to prolongate timer each fragment arrival 685 * by TTL. 686 */ 687 net->ipv4.fqdir->timeout = IP_FRAG_TIME; 688 689 net->ipv4.fqdir->max_dist = 64; 690 691 res = ip4_frags_ns_ctl_register(net); 692 if (res < 0) 693 fqdir_exit(net->ipv4.fqdir); 694 return res; 695 } 696 697 static void __net_exit ipv4_frags_pre_exit_net(struct net *net) 698 { 699 fqdir_pre_exit(net->ipv4.fqdir); 700 } 701 702 static void __net_exit ipv4_frags_exit_net(struct net *net) 703 { 704 ip4_frags_ns_ctl_unregister(net); 705 fqdir_exit(net->ipv4.fqdir); 706 } 707 708 static struct pernet_operations ip4_frags_ops = { 709 .init = ipv4_frags_init_net, 710 .pre_exit = ipv4_frags_pre_exit_net, 711 .exit = ipv4_frags_exit_net, 712 }; 713 714 715 static u32 ip4_key_hashfn(const void *data, u32 len, u32 seed) 716 { 717 return jhash2(data, 718 sizeof(struct frag_v4_compare_key) / sizeof(u32), seed); 719 } 720 721 static u32 ip4_obj_hashfn(const void *data, u32 len, u32 seed) 722 { 723 const struct inet_frag_queue *fq = data; 724 725 return jhash2((const u32 *)&fq->key.v4, 726 sizeof(struct frag_v4_compare_key) / sizeof(u32), seed); 727 } 728 729 static int ip4_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr) 730 { 731 const struct frag_v4_compare_key *key = arg->key; 732 const struct inet_frag_queue *fq = ptr; 733 734 return !!memcmp(&fq->key, key, sizeof(*key)); 735 } 736 737 static const struct rhashtable_params ip4_rhash_params = { 738 .head_offset = offsetof(struct inet_frag_queue, node), 739 .key_offset = offsetof(struct inet_frag_queue, key), 740 .key_len = sizeof(struct frag_v4_compare_key), 741 .hashfn = ip4_key_hashfn, 742 .obj_hashfn = ip4_obj_hashfn, 743 .obj_cmpfn = ip4_obj_cmpfn, 744 .automatic_shrinking = true, 745 }; 746 747 void __init ipfrag_init(void) 748 { 749 ip4_frags.constructor = ip4_frag_init; 750 ip4_frags.destructor = ip4_frag_free; 751 ip4_frags.qsize = sizeof(struct ipq); 752 ip4_frags.frag_expire = ip_expire; 753 ip4_frags.frags_cache_name = ip_frag_cache_name; 754 ip4_frags.rhash_params = ip4_rhash_params; 755 if (inet_frags_init(&ip4_frags)) 756 panic("IP: failed to allocate ip4_frags cache\n"); 757 ip4_frags_ctl_register(); 758 register_pernet_subsys(&ip4_frags_ops); 759 } 760