1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * The IP fragmentation functionality. 7 * 8 * Authors: Fred N. van Kempen <waltje@uWalt.NL.Mugnet.ORG> 9 * Alan Cox <alan@lxorguk.ukuu.org.uk> 10 * 11 * Fixes: 12 * Alan Cox : Split from ip.c , see ip_input.c for history. 13 * David S. Miller : Begin massive cleanup... 14 * Andi Kleen : Add sysctls. 15 * xxxx : Overlapfrag bug. 16 * Ultima : ip_expire() kernel panic. 17 * Bill Hawes : Frag accounting and evictor fixes. 18 * John McDonald : 0 length frag bug. 19 * Alexey Kuznetsov: SMP races, threading, cleanup. 20 * Patrick McHardy : LRU queue of frag heads for evictor. 21 */ 22 23 #define pr_fmt(fmt) "IPv4: " fmt 24 25 #include <linux/compiler.h> 26 #include <linux/module.h> 27 #include <linux/types.h> 28 #include <linux/mm.h> 29 #include <linux/jiffies.h> 30 #include <linux/skbuff.h> 31 #include <linux/list.h> 32 #include <linux/ip.h> 33 #include <linux/icmp.h> 34 #include <linux/netdevice.h> 35 #include <linux/jhash.h> 36 #include <linux/random.h> 37 #include <linux/slab.h> 38 #include <net/route.h> 39 #include <net/dst.h> 40 #include <net/sock.h> 41 #include <net/ip.h> 42 #include <net/icmp.h> 43 #include <net/checksum.h> 44 #include <net/inetpeer.h> 45 #include <net/inet_frag.h> 46 #include <linux/tcp.h> 47 #include <linux/udp.h> 48 #include <linux/inet.h> 49 #include <linux/netfilter_ipv4.h> 50 #include <net/inet_ecn.h> 51 #include <net/l3mdev.h> 52 53 /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6 54 * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c 55 * as well. Or notify me, at least. --ANK 56 */ 57 static const char ip_frag_cache_name[] = "ip4-frags"; 58 59 struct ipfrag_skb_cb 60 { 61 struct inet_skb_parm h; 62 int offset; 63 }; 64 65 #define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) 66 67 /* Describe an entry in the "incomplete datagrams" queue. */ 68 struct ipq { 69 struct inet_frag_queue q; 70 71 u32 user; 72 __be32 saddr; 73 __be32 daddr; 74 __be16 id; 75 u8 protocol; 76 u8 ecn; /* RFC3168 support */ 77 u16 max_df_size; /* largest frag with DF set seen */ 78 int iif; 79 int vif; /* L3 master device index */ 80 unsigned int rid; 81 struct inet_peer *peer; 82 }; 83 84 static u8 ip4_frag_ecn(u8 tos) 85 { 86 return 1 << (tos & INET_ECN_MASK); 87 } 88 89 static struct inet_frags ip4_frags; 90 91 int ip_frag_mem(struct net *net) 92 { 93 return sum_frag_mem_limit(&net->ipv4.frags); 94 } 95 96 static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 97 struct net_device *dev); 98 99 struct ip4_create_arg { 100 struct iphdr *iph; 101 u32 user; 102 int vif; 103 }; 104 105 static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) 106 { 107 net_get_random_once(&ip4_frags.rnd, sizeof(ip4_frags.rnd)); 108 return jhash_3words((__force u32)id << 16 | prot, 109 (__force u32)saddr, (__force u32)daddr, 110 ip4_frags.rnd); 111 } 112 113 static unsigned int ip4_hashfn(const struct inet_frag_queue *q) 114 { 115 const struct ipq *ipq; 116 117 ipq = container_of(q, struct ipq, q); 118 return ipqhashfn(ipq->id, ipq->saddr, ipq->daddr, ipq->protocol); 119 } 120 121 static bool ip4_frag_match(const struct inet_frag_queue *q, const void *a) 122 { 123 const struct ipq *qp; 124 const struct ip4_create_arg *arg = a; 125 126 qp = container_of(q, struct ipq, q); 127 return qp->id == arg->iph->id && 128 qp->saddr == arg->iph->saddr && 129 qp->daddr == arg->iph->daddr && 130 qp->protocol == arg->iph->protocol && 131 qp->user == arg->user && 132 qp->vif == arg->vif; 133 } 134 135 static void ip4_frag_init(struct inet_frag_queue *q, const void *a) 136 { 137 struct ipq *qp = container_of(q, struct ipq, q); 138 struct netns_ipv4 *ipv4 = container_of(q->net, struct netns_ipv4, 139 frags); 140 struct net *net = container_of(ipv4, struct net, ipv4); 141 142 const struct ip4_create_arg *arg = a; 143 144 qp->protocol = arg->iph->protocol; 145 qp->id = arg->iph->id; 146 qp->ecn = ip4_frag_ecn(arg->iph->tos); 147 qp->saddr = arg->iph->saddr; 148 qp->daddr = arg->iph->daddr; 149 qp->vif = arg->vif; 150 qp->user = arg->user; 151 qp->peer = q->net->max_dist ? 152 inet_getpeer_v4(net->ipv4.peers, arg->iph->saddr, arg->vif, 1) : 153 NULL; 154 } 155 156 static void ip4_frag_free(struct inet_frag_queue *q) 157 { 158 struct ipq *qp; 159 160 qp = container_of(q, struct ipq, q); 161 if (qp->peer) 162 inet_putpeer(qp->peer); 163 } 164 165 166 /* Destruction primitives. */ 167 168 static void ipq_put(struct ipq *ipq) 169 { 170 inet_frag_put(&ipq->q, &ip4_frags); 171 } 172 173 /* Kill ipq entry. It is not destroyed immediately, 174 * because caller (and someone more) holds reference count. 175 */ 176 static void ipq_kill(struct ipq *ipq) 177 { 178 inet_frag_kill(&ipq->q, &ip4_frags); 179 } 180 181 static bool frag_expire_skip_icmp(u32 user) 182 { 183 return user == IP_DEFRAG_AF_PACKET || 184 ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_IN, 185 __IP_DEFRAG_CONNTRACK_IN_END) || 186 ip_defrag_user_in_between(user, IP_DEFRAG_CONNTRACK_BRIDGE_IN, 187 __IP_DEFRAG_CONNTRACK_BRIDGE_IN); 188 } 189 190 /* 191 * Oops, a fragment queue timed out. Kill it and send an ICMP reply. 192 */ 193 static void ip_expire(unsigned long arg) 194 { 195 struct ipq *qp; 196 struct net *net; 197 198 qp = container_of((struct inet_frag_queue *) arg, struct ipq, q); 199 net = container_of(qp->q.net, struct net, ipv4.frags); 200 201 spin_lock(&qp->q.lock); 202 203 if (qp->q.flags & INET_FRAG_COMPLETE) 204 goto out; 205 206 ipq_kill(qp); 207 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 208 209 if (!inet_frag_evicting(&qp->q)) { 210 struct sk_buff *head = qp->q.fragments; 211 const struct iphdr *iph; 212 int err; 213 214 __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT); 215 216 if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments) 217 goto out; 218 219 rcu_read_lock(); 220 head->dev = dev_get_by_index_rcu(net, qp->iif); 221 if (!head->dev) 222 goto out_rcu_unlock; 223 224 /* skb has no dst, perform route lookup again */ 225 iph = ip_hdr(head); 226 err = ip_route_input_noref(head, iph->daddr, iph->saddr, 227 iph->tos, head->dev); 228 if (err) 229 goto out_rcu_unlock; 230 231 /* Only an end host needs to send an ICMP 232 * "Fragment Reassembly Timeout" message, per RFC792. 233 */ 234 if (frag_expire_skip_icmp(qp->user) && 235 (skb_rtable(head)->rt_type != RTN_LOCAL)) 236 goto out_rcu_unlock; 237 238 /* Send an ICMP "Fragment Reassembly Timeout" message. */ 239 icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); 240 out_rcu_unlock: 241 rcu_read_unlock(); 242 } 243 out: 244 spin_unlock(&qp->q.lock); 245 ipq_put(qp); 246 } 247 248 /* Find the correct entry in the "incomplete datagrams" queue for 249 * this IP datagram, and create new one, if nothing is found. 250 */ 251 static struct ipq *ip_find(struct net *net, struct iphdr *iph, 252 u32 user, int vif) 253 { 254 struct inet_frag_queue *q; 255 struct ip4_create_arg arg; 256 unsigned int hash; 257 258 arg.iph = iph; 259 arg.user = user; 260 arg.vif = vif; 261 262 hash = ipqhashfn(iph->id, iph->saddr, iph->daddr, iph->protocol); 263 264 q = inet_frag_find(&net->ipv4.frags, &ip4_frags, &arg, hash); 265 if (IS_ERR_OR_NULL(q)) { 266 inet_frag_maybe_warn_overflow(q, pr_fmt()); 267 return NULL; 268 } 269 return container_of(q, struct ipq, q); 270 } 271 272 /* Is the fragment too far ahead to be part of ipq? */ 273 static int ip_frag_too_far(struct ipq *qp) 274 { 275 struct inet_peer *peer = qp->peer; 276 unsigned int max = qp->q.net->max_dist; 277 unsigned int start, end; 278 279 int rc; 280 281 if (!peer || !max) 282 return 0; 283 284 start = qp->rid; 285 end = atomic_inc_return(&peer->rid); 286 qp->rid = end; 287 288 rc = qp->q.fragments && (end - start) > max; 289 290 if (rc) { 291 struct net *net; 292 293 net = container_of(qp->q.net, struct net, ipv4.frags); 294 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 295 } 296 297 return rc; 298 } 299 300 static int ip_frag_reinit(struct ipq *qp) 301 { 302 struct sk_buff *fp; 303 unsigned int sum_truesize = 0; 304 305 if (!mod_timer(&qp->q.timer, jiffies + qp->q.net->timeout)) { 306 atomic_inc(&qp->q.refcnt); 307 return -ETIMEDOUT; 308 } 309 310 fp = qp->q.fragments; 311 do { 312 struct sk_buff *xp = fp->next; 313 314 sum_truesize += fp->truesize; 315 kfree_skb(fp); 316 fp = xp; 317 } while (fp); 318 sub_frag_mem_limit(qp->q.net, sum_truesize); 319 320 qp->q.flags = 0; 321 qp->q.len = 0; 322 qp->q.meat = 0; 323 qp->q.fragments = NULL; 324 qp->q.fragments_tail = NULL; 325 qp->iif = 0; 326 qp->ecn = 0; 327 328 return 0; 329 } 330 331 /* Add new segment to existing queue. */ 332 static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) 333 { 334 struct sk_buff *prev, *next; 335 struct net_device *dev; 336 unsigned int fragsize; 337 int flags, offset; 338 int ihl, end; 339 int err = -ENOENT; 340 u8 ecn; 341 342 if (qp->q.flags & INET_FRAG_COMPLETE) 343 goto err; 344 345 if (!(IPCB(skb)->flags & IPSKB_FRAG_COMPLETE) && 346 unlikely(ip_frag_too_far(qp)) && 347 unlikely(err = ip_frag_reinit(qp))) { 348 ipq_kill(qp); 349 goto err; 350 } 351 352 ecn = ip4_frag_ecn(ip_hdr(skb)->tos); 353 offset = ntohs(ip_hdr(skb)->frag_off); 354 flags = offset & ~IP_OFFSET; 355 offset &= IP_OFFSET; 356 offset <<= 3; /* offset is in 8-byte chunks */ 357 ihl = ip_hdrlen(skb); 358 359 /* Determine the position of this fragment. */ 360 end = offset + skb->len - skb_network_offset(skb) - ihl; 361 err = -EINVAL; 362 363 /* Is this the final fragment? */ 364 if ((flags & IP_MF) == 0) { 365 /* If we already have some bits beyond end 366 * or have different end, the segment is corrupted. 367 */ 368 if (end < qp->q.len || 369 ((qp->q.flags & INET_FRAG_LAST_IN) && end != qp->q.len)) 370 goto err; 371 qp->q.flags |= INET_FRAG_LAST_IN; 372 qp->q.len = end; 373 } else { 374 if (end&7) { 375 end &= ~7; 376 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 377 skb->ip_summed = CHECKSUM_NONE; 378 } 379 if (end > qp->q.len) { 380 /* Some bits beyond end -> corruption. */ 381 if (qp->q.flags & INET_FRAG_LAST_IN) 382 goto err; 383 qp->q.len = end; 384 } 385 } 386 if (end == offset) 387 goto err; 388 389 err = -ENOMEM; 390 if (!pskb_pull(skb, skb_network_offset(skb) + ihl)) 391 goto err; 392 393 err = pskb_trim_rcsum(skb, end - offset); 394 if (err) 395 goto err; 396 397 /* Find out which fragments are in front and at the back of us 398 * in the chain of fragments so far. We must know where to put 399 * this fragment, right? 400 */ 401 prev = qp->q.fragments_tail; 402 if (!prev || FRAG_CB(prev)->offset < offset) { 403 next = NULL; 404 goto found; 405 } 406 prev = NULL; 407 for (next = qp->q.fragments; next != NULL; next = next->next) { 408 if (FRAG_CB(next)->offset >= offset) 409 break; /* bingo! */ 410 prev = next; 411 } 412 413 found: 414 /* We found where to put this one. Check for overlap with 415 * preceding fragment, and, if needed, align things so that 416 * any overlaps are eliminated. 417 */ 418 if (prev) { 419 int i = (FRAG_CB(prev)->offset + prev->len) - offset; 420 421 if (i > 0) { 422 offset += i; 423 err = -EINVAL; 424 if (end <= offset) 425 goto err; 426 err = -ENOMEM; 427 if (!pskb_pull(skb, i)) 428 goto err; 429 if (skb->ip_summed != CHECKSUM_UNNECESSARY) 430 skb->ip_summed = CHECKSUM_NONE; 431 } 432 } 433 434 err = -ENOMEM; 435 436 while (next && FRAG_CB(next)->offset < end) { 437 int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ 438 439 if (i < next->len) { 440 /* Eat head of the next overlapped fragment 441 * and leave the loop. The next ones cannot overlap. 442 */ 443 if (!pskb_pull(next, i)) 444 goto err; 445 FRAG_CB(next)->offset += i; 446 qp->q.meat -= i; 447 if (next->ip_summed != CHECKSUM_UNNECESSARY) 448 next->ip_summed = CHECKSUM_NONE; 449 break; 450 } else { 451 struct sk_buff *free_it = next; 452 453 /* Old fragment is completely overridden with 454 * new one drop it. 455 */ 456 next = next->next; 457 458 if (prev) 459 prev->next = next; 460 else 461 qp->q.fragments = next; 462 463 qp->q.meat -= free_it->len; 464 sub_frag_mem_limit(qp->q.net, free_it->truesize); 465 kfree_skb(free_it); 466 } 467 } 468 469 FRAG_CB(skb)->offset = offset; 470 471 /* Insert this fragment in the chain of fragments. */ 472 skb->next = next; 473 if (!next) 474 qp->q.fragments_tail = skb; 475 if (prev) 476 prev->next = skb; 477 else 478 qp->q.fragments = skb; 479 480 dev = skb->dev; 481 if (dev) { 482 qp->iif = dev->ifindex; 483 skb->dev = NULL; 484 } 485 qp->q.stamp = skb->tstamp; 486 qp->q.meat += skb->len; 487 qp->ecn |= ecn; 488 add_frag_mem_limit(qp->q.net, skb->truesize); 489 if (offset == 0) 490 qp->q.flags |= INET_FRAG_FIRST_IN; 491 492 fragsize = skb->len + ihl; 493 494 if (fragsize > qp->q.max_size) 495 qp->q.max_size = fragsize; 496 497 if (ip_hdr(skb)->frag_off & htons(IP_DF) && 498 fragsize > qp->max_df_size) 499 qp->max_df_size = fragsize; 500 501 if (qp->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && 502 qp->q.meat == qp->q.len) { 503 unsigned long orefdst = skb->_skb_refdst; 504 505 skb->_skb_refdst = 0UL; 506 err = ip_frag_reasm(qp, prev, dev); 507 skb->_skb_refdst = orefdst; 508 return err; 509 } 510 511 skb_dst_drop(skb); 512 return -EINPROGRESS; 513 514 err: 515 kfree_skb(skb); 516 return err; 517 } 518 519 520 /* Build a new IP datagram from all its fragments. */ 521 522 static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, 523 struct net_device *dev) 524 { 525 struct net *net = container_of(qp->q.net, struct net, ipv4.frags); 526 struct iphdr *iph; 527 struct sk_buff *fp, *head = qp->q.fragments; 528 int len; 529 int ihlen; 530 int err; 531 u8 ecn; 532 533 ipq_kill(qp); 534 535 ecn = ip_frag_ecn_table[qp->ecn]; 536 if (unlikely(ecn == 0xff)) { 537 err = -EINVAL; 538 goto out_fail; 539 } 540 /* Make the one we just received the head. */ 541 if (prev) { 542 head = prev->next; 543 fp = skb_clone(head, GFP_ATOMIC); 544 if (!fp) 545 goto out_nomem; 546 547 fp->next = head->next; 548 if (!fp->next) 549 qp->q.fragments_tail = fp; 550 prev->next = fp; 551 552 skb_morph(head, qp->q.fragments); 553 head->next = qp->q.fragments->next; 554 555 consume_skb(qp->q.fragments); 556 qp->q.fragments = head; 557 } 558 559 WARN_ON(!head); 560 WARN_ON(FRAG_CB(head)->offset != 0); 561 562 /* Allocate a new buffer for the datagram. */ 563 ihlen = ip_hdrlen(head); 564 len = ihlen + qp->q.len; 565 566 err = -E2BIG; 567 if (len > 65535) 568 goto out_oversize; 569 570 /* Head of list must not be cloned. */ 571 if (skb_unclone(head, GFP_ATOMIC)) 572 goto out_nomem; 573 574 /* If the first fragment is fragmented itself, we split 575 * it to two chunks: the first with data and paged part 576 * and the second, holding only fragments. */ 577 if (skb_has_frag_list(head)) { 578 struct sk_buff *clone; 579 int i, plen = 0; 580 581 clone = alloc_skb(0, GFP_ATOMIC); 582 if (!clone) 583 goto out_nomem; 584 clone->next = head->next; 585 head->next = clone; 586 skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; 587 skb_frag_list_init(head); 588 for (i = 0; i < skb_shinfo(head)->nr_frags; i++) 589 plen += skb_frag_size(&skb_shinfo(head)->frags[i]); 590 clone->len = clone->data_len = head->data_len - plen; 591 head->data_len -= clone->len; 592 head->len -= clone->len; 593 clone->csum = 0; 594 clone->ip_summed = head->ip_summed; 595 add_frag_mem_limit(qp->q.net, clone->truesize); 596 } 597 598 skb_shinfo(head)->frag_list = head->next; 599 skb_push(head, head->data - skb_network_header(head)); 600 601 for (fp=head->next; fp; fp = fp->next) { 602 head->data_len += fp->len; 603 head->len += fp->len; 604 if (head->ip_summed != fp->ip_summed) 605 head->ip_summed = CHECKSUM_NONE; 606 else if (head->ip_summed == CHECKSUM_COMPLETE) 607 head->csum = csum_add(head->csum, fp->csum); 608 head->truesize += fp->truesize; 609 } 610 sub_frag_mem_limit(qp->q.net, head->truesize); 611 612 head->next = NULL; 613 head->dev = dev; 614 head->tstamp = qp->q.stamp; 615 IPCB(head)->frag_max_size = max(qp->max_df_size, qp->q.max_size); 616 617 iph = ip_hdr(head); 618 iph->tot_len = htons(len); 619 iph->tos |= ecn; 620 621 /* When we set IP_DF on a refragmented skb we must also force a 622 * call to ip_fragment to avoid forwarding a DF-skb of size s while 623 * original sender only sent fragments of size f (where f < s). 624 * 625 * We only set DF/IPSKB_FRAG_PMTU if such DF fragment was the largest 626 * frag seen to avoid sending tiny DF-fragments in case skb was built 627 * from one very small df-fragment and one large non-df frag. 628 */ 629 if (qp->max_df_size == qp->q.max_size) { 630 IPCB(head)->flags |= IPSKB_FRAG_PMTU; 631 iph->frag_off = htons(IP_DF); 632 } else { 633 iph->frag_off = 0; 634 } 635 636 ip_send_check(iph); 637 638 __IP_INC_STATS(net, IPSTATS_MIB_REASMOKS); 639 qp->q.fragments = NULL; 640 qp->q.fragments_tail = NULL; 641 return 0; 642 643 out_nomem: 644 net_dbg_ratelimited("queue_glue: no memory for gluing queue %p\n", qp); 645 err = -ENOMEM; 646 goto out_fail; 647 out_oversize: 648 net_info_ratelimited("Oversized IP packet from %pI4\n", &qp->saddr); 649 out_fail: 650 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 651 return err; 652 } 653 654 /* Process an incoming IP datagram fragment. */ 655 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user) 656 { 657 struct net_device *dev = skb->dev ? : skb_dst(skb)->dev; 658 int vif = l3mdev_master_ifindex_rcu(dev); 659 struct ipq *qp; 660 661 __IP_INC_STATS(net, IPSTATS_MIB_REASMREQDS); 662 skb_orphan(skb); 663 664 /* Lookup (or create) queue header */ 665 qp = ip_find(net, ip_hdr(skb), user, vif); 666 if (qp) { 667 int ret; 668 669 spin_lock(&qp->q.lock); 670 671 ret = ip_frag_queue(qp, skb); 672 673 spin_unlock(&qp->q.lock); 674 ipq_put(qp); 675 return ret; 676 } 677 678 __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); 679 kfree_skb(skb); 680 return -ENOMEM; 681 } 682 EXPORT_SYMBOL(ip_defrag); 683 684 struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user) 685 { 686 struct iphdr iph; 687 int netoff; 688 u32 len; 689 690 if (skb->protocol != htons(ETH_P_IP)) 691 return skb; 692 693 netoff = skb_network_offset(skb); 694 695 if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) 696 return skb; 697 698 if (iph.ihl < 5 || iph.version != 4) 699 return skb; 700 701 len = ntohs(iph.tot_len); 702 if (skb->len < netoff + len || len < (iph.ihl * 4)) 703 return skb; 704 705 if (ip_is_fragment(&iph)) { 706 skb = skb_share_check(skb, GFP_ATOMIC); 707 if (skb) { 708 if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) 709 return skb; 710 if (pskb_trim_rcsum(skb, netoff + len)) 711 return skb; 712 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 713 if (ip_defrag(net, skb, user)) 714 return NULL; 715 skb_clear_hash(skb); 716 } 717 } 718 return skb; 719 } 720 EXPORT_SYMBOL(ip_check_defrag); 721 722 #ifdef CONFIG_SYSCTL 723 static int zero; 724 725 static struct ctl_table ip4_frags_ns_ctl_table[] = { 726 { 727 .procname = "ipfrag_high_thresh", 728 .data = &init_net.ipv4.frags.high_thresh, 729 .maxlen = sizeof(int), 730 .mode = 0644, 731 .proc_handler = proc_dointvec_minmax, 732 .extra1 = &init_net.ipv4.frags.low_thresh 733 }, 734 { 735 .procname = "ipfrag_low_thresh", 736 .data = &init_net.ipv4.frags.low_thresh, 737 .maxlen = sizeof(int), 738 .mode = 0644, 739 .proc_handler = proc_dointvec_minmax, 740 .extra1 = &zero, 741 .extra2 = &init_net.ipv4.frags.high_thresh 742 }, 743 { 744 .procname = "ipfrag_time", 745 .data = &init_net.ipv4.frags.timeout, 746 .maxlen = sizeof(int), 747 .mode = 0644, 748 .proc_handler = proc_dointvec_jiffies, 749 }, 750 { 751 .procname = "ipfrag_max_dist", 752 .data = &init_net.ipv4.frags.max_dist, 753 .maxlen = sizeof(int), 754 .mode = 0644, 755 .proc_handler = proc_dointvec_minmax, 756 .extra1 = &zero 757 }, 758 { } 759 }; 760 761 /* secret interval has been deprecated */ 762 static int ip4_frags_secret_interval_unused; 763 static struct ctl_table ip4_frags_ctl_table[] = { 764 { 765 .procname = "ipfrag_secret_interval", 766 .data = &ip4_frags_secret_interval_unused, 767 .maxlen = sizeof(int), 768 .mode = 0644, 769 .proc_handler = proc_dointvec_jiffies, 770 }, 771 { } 772 }; 773 774 static int __net_init ip4_frags_ns_ctl_register(struct net *net) 775 { 776 struct ctl_table *table; 777 struct ctl_table_header *hdr; 778 779 table = ip4_frags_ns_ctl_table; 780 if (!net_eq(net, &init_net)) { 781 table = kmemdup(table, sizeof(ip4_frags_ns_ctl_table), GFP_KERNEL); 782 if (!table) 783 goto err_alloc; 784 785 table[0].data = &net->ipv4.frags.high_thresh; 786 table[0].extra1 = &net->ipv4.frags.low_thresh; 787 table[0].extra2 = &init_net.ipv4.frags.high_thresh; 788 table[1].data = &net->ipv4.frags.low_thresh; 789 table[1].extra2 = &net->ipv4.frags.high_thresh; 790 table[2].data = &net->ipv4.frags.timeout; 791 table[3].data = &net->ipv4.frags.max_dist; 792 } 793 794 hdr = register_net_sysctl(net, "net/ipv4", table); 795 if (!hdr) 796 goto err_reg; 797 798 net->ipv4.frags_hdr = hdr; 799 return 0; 800 801 err_reg: 802 if (!net_eq(net, &init_net)) 803 kfree(table); 804 err_alloc: 805 return -ENOMEM; 806 } 807 808 static void __net_exit ip4_frags_ns_ctl_unregister(struct net *net) 809 { 810 struct ctl_table *table; 811 812 table = net->ipv4.frags_hdr->ctl_table_arg; 813 unregister_net_sysctl_table(net->ipv4.frags_hdr); 814 kfree(table); 815 } 816 817 static void __init ip4_frags_ctl_register(void) 818 { 819 register_net_sysctl(&init_net, "net/ipv4", ip4_frags_ctl_table); 820 } 821 #else 822 static int ip4_frags_ns_ctl_register(struct net *net) 823 { 824 return 0; 825 } 826 827 static void ip4_frags_ns_ctl_unregister(struct net *net) 828 { 829 } 830 831 static void __init ip4_frags_ctl_register(void) 832 { 833 } 834 #endif 835 836 static int __net_init ipv4_frags_init_net(struct net *net) 837 { 838 int res; 839 840 /* Fragment cache limits. 841 * 842 * The fragment memory accounting code, (tries to) account for 843 * the real memory usage, by measuring both the size of frag 844 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) 845 * and the SKB's truesize. 846 * 847 * A 64K fragment consumes 129736 bytes (44*2944)+200 848 * (1500 truesize == 2944, sizeof(struct ipq) == 200) 849 * 850 * We will commit 4MB at one time. Should we cross that limit 851 * we will prune down to 3MB, making room for approx 8 big 64K 852 * fragments 8x128k. 853 */ 854 net->ipv4.frags.high_thresh = 4 * 1024 * 1024; 855 net->ipv4.frags.low_thresh = 3 * 1024 * 1024; 856 /* 857 * Important NOTE! Fragment queue must be destroyed before MSL expires. 858 * RFC791 is wrong proposing to prolongate timer each fragment arrival 859 * by TTL. 860 */ 861 net->ipv4.frags.timeout = IP_FRAG_TIME; 862 863 net->ipv4.frags.max_dist = 64; 864 865 res = inet_frags_init_net(&net->ipv4.frags); 866 if (res) 867 return res; 868 res = ip4_frags_ns_ctl_register(net); 869 if (res) 870 inet_frags_uninit_net(&net->ipv4.frags); 871 return res; 872 } 873 874 static void __net_exit ipv4_frags_exit_net(struct net *net) 875 { 876 ip4_frags_ns_ctl_unregister(net); 877 inet_frags_exit_net(&net->ipv4.frags, &ip4_frags); 878 } 879 880 static struct pernet_operations ip4_frags_ops = { 881 .init = ipv4_frags_init_net, 882 .exit = ipv4_frags_exit_net, 883 }; 884 885 void __init ipfrag_init(void) 886 { 887 ip4_frags_ctl_register(); 888 register_pernet_subsys(&ip4_frags_ops); 889 ip4_frags.hashfn = ip4_hashfn; 890 ip4_frags.constructor = ip4_frag_init; 891 ip4_frags.destructor = ip4_frag_free; 892 ip4_frags.qsize = sizeof(struct ipq); 893 ip4_frags.match = ip4_frag_match; 894 ip4_frags.frag_expire = ip_expire; 895 ip4_frags.frags_cache_name = ip_frag_cache_name; 896 if (inet_frags_init(&ip4_frags)) 897 panic("IP: failed to allocate ip4_frags cache\n"); 898 } 899