1 // SPDX-License-Identifier: GPL-2.0-or-later 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 Internet Protocol (IP) module. 8 * 9 * Authors: Ross Biro 10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 11 * Donald Becker, <becker@super.org> 12 * Alan Cox, <alan@lxorguk.ukuu.org.uk> 13 * Richard Underwood 14 * Stefan Becker, <stefanb@yello.ping.de> 15 * Jorge Cwik, <jorge@laser.satlink.net> 16 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 17 * 18 * Fixes: 19 * Alan Cox : Commented a couple of minor bits of surplus code 20 * Alan Cox : Undefining IP_FORWARD doesn't include the code 21 * (just stops a compiler warning). 22 * Alan Cox : Frames with >=MAX_ROUTE record routes, strict routes or loose routes 23 * are junked rather than corrupting things. 24 * Alan Cox : Frames to bad broadcast subnets are dumped 25 * We used to process them non broadcast and 26 * boy could that cause havoc. 27 * Alan Cox : ip_forward sets the free flag on the 28 * new frame it queues. Still crap because 29 * it copies the frame but at least it 30 * doesn't eat memory too. 31 * Alan Cox : Generic queue code and memory fixes. 32 * Fred Van Kempen : IP fragment support (borrowed from NET2E) 33 * Gerhard Koerting: Forward fragmented frames correctly. 34 * Gerhard Koerting: Fixes to my fix of the above 8-). 35 * Gerhard Koerting: IP interface addressing fix. 36 * Linus Torvalds : More robustness checks 37 * Alan Cox : Even more checks: Still not as robust as it ought to be 38 * Alan Cox : Save IP header pointer for later 39 * Alan Cox : ip option setting 40 * Alan Cox : Use ip_tos/ip_ttl settings 41 * Alan Cox : Fragmentation bogosity removed 42 * (Thanks to Mark.Bush@prg.ox.ac.uk) 43 * Dmitry Gorodchanin : Send of a raw packet crash fix. 44 * Alan Cox : Silly ip bug when an overlength 45 * fragment turns up. Now frees the 46 * queue. 47 * Linus Torvalds/ : Memory leakage on fragmentation 48 * Alan Cox : handling. 49 * Gerhard Koerting: Forwarding uses IP priority hints 50 * Teemu Rantanen : Fragment problems. 51 * Alan Cox : General cleanup, comments and reformat 52 * Alan Cox : SNMP statistics 53 * Alan Cox : BSD address rule semantics. Also see 54 * UDP as there is a nasty checksum issue 55 * if you do things the wrong way. 56 * Alan Cox : Always defrag, moved IP_FORWARD to the config.in file 57 * Alan Cox : IP options adjust sk->priority. 58 * Pedro Roque : Fix mtu/length error in ip_forward. 59 * Alan Cox : Avoid ip_chk_addr when possible. 60 * Richard Underwood : IP multicasting. 61 * Alan Cox : Cleaned up multicast handlers. 62 * Alan Cox : RAW sockets demultiplex in the BSD style. 63 * Gunther Mayer : Fix the SNMP reporting typo 64 * Alan Cox : Always in group 224.0.0.1 65 * Pauline Middelink : Fast ip_checksum update when forwarding 66 * Masquerading support. 67 * Alan Cox : Multicast loopback error for 224.0.0.1 68 * Alan Cox : IP_MULTICAST_LOOP option. 69 * Alan Cox : Use notifiers. 70 * Bjorn Ekwall : Removed ip_csum (from slhc.c too) 71 * Bjorn Ekwall : Moved ip_fast_csum to ip.h (inline!) 72 * Stefan Becker : Send out ICMP HOST REDIRECT 73 * Arnt Gulbrandsen : ip_build_xmit 74 * Alan Cox : Per socket routing cache 75 * Alan Cox : Fixed routing cache, added header cache. 76 * Alan Cox : Loopback didn't work right in original ip_build_xmit - fixed it. 77 * Alan Cox : Only send ICMP_REDIRECT if src/dest are the same net. 78 * Alan Cox : Incoming IP option handling. 79 * Alan Cox : Set saddr on raw output frames as per BSD. 80 * Alan Cox : Stopped broadcast source route explosions. 81 * Alan Cox : Can disable source routing 82 * Takeshi Sone : Masquerading didn't work. 83 * Dave Bonn,Alan Cox : Faster IP forwarding whenever possible. 84 * Alan Cox : Memory leaks, tramples, misc debugging. 85 * Alan Cox : Fixed multicast (by popular demand 8)) 86 * Alan Cox : Fixed forwarding (by even more popular demand 8)) 87 * Alan Cox : Fixed SNMP statistics [I think] 88 * Gerhard Koerting : IP fragmentation forwarding fix 89 * Alan Cox : Device lock against page fault. 90 * Alan Cox : IP_HDRINCL facility. 91 * Werner Almesberger : Zero fragment bug 92 * Alan Cox : RAW IP frame length bug 93 * Alan Cox : Outgoing firewall on build_xmit 94 * A.N.Kuznetsov : IP_OPTIONS support throughout the kernel 95 * Alan Cox : Multicast routing hooks 96 * Jos Vos : Do accounting *before* call_in_firewall 97 * Willy Konynenberg : Transparent proxying support 98 * 99 * To Fix: 100 * IP fragmentation wants rewriting cleanly. The RFC815 algorithm is much more efficient 101 * and could be made very efficient with the addition of some virtual memory hacks to permit 102 * the allocation of a buffer that can then be 'grown' by twiddling page tables. 103 * Output fragmentation wants updating along with the buffer management to use a single 104 * interleaved copy algorithm so that fragmenting has a one copy overhead. Actual packet 105 * output should probably do its own fragmentation at the UDP/RAW layer. TCP shouldn't cause 106 * fragmentation anyway. 107 */ 108 109 #define pr_fmt(fmt) "IPv4: " fmt 110 111 #include <linux/module.h> 112 #include <linux/types.h> 113 #include <linux/kernel.h> 114 #include <linux/string.h> 115 #include <linux/errno.h> 116 #include <linux/slab.h> 117 118 #include <linux/net.h> 119 #include <linux/socket.h> 120 #include <linux/sockios.h> 121 #include <linux/in.h> 122 #include <linux/inet.h> 123 #include <linux/inetdevice.h> 124 #include <linux/netdevice.h> 125 #include <linux/etherdevice.h> 126 #include <linux/indirect_call_wrapper.h> 127 128 #include <net/snmp.h> 129 #include <net/ip.h> 130 #include <net/protocol.h> 131 #include <net/route.h> 132 #include <linux/skbuff.h> 133 #include <net/sock.h> 134 #include <net/arp.h> 135 #include <net/icmp.h> 136 #include <net/raw.h> 137 #include <net/checksum.h> 138 #include <net/inet_ecn.h> 139 #include <linux/netfilter_ipv4.h> 140 #include <net/xfrm.h> 141 #include <linux/mroute.h> 142 #include <linux/netlink.h> 143 #include <net/dst_metadata.h> 144 145 /* 146 * Process Router Attention IP option (RFC 2113) 147 */ 148 bool ip_call_ra_chain(struct sk_buff *skb) 149 { 150 struct ip_ra_chain *ra; 151 u8 protocol = ip_hdr(skb)->protocol; 152 struct sock *last = NULL; 153 struct net_device *dev = skb->dev; 154 struct net *net = dev_net(dev); 155 156 for (ra = rcu_dereference(net->ipv4.ra_chain); ra; ra = rcu_dereference(ra->next)) { 157 struct sock *sk = ra->sk; 158 159 /* If socket is bound to an interface, only report 160 * the packet if it came from that interface. 161 */ 162 if (sk && inet_sk(sk)->inet_num == protocol && 163 (!sk->sk_bound_dev_if || 164 sk->sk_bound_dev_if == dev->ifindex)) { 165 if (ip_is_fragment(ip_hdr(skb))) { 166 if (ip_defrag(net, skb, IP_DEFRAG_CALL_RA_CHAIN)) 167 return true; 168 } 169 if (last) { 170 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 171 if (skb2) 172 raw_rcv(last, skb2); 173 } 174 last = sk; 175 } 176 } 177 178 if (last) { 179 raw_rcv(last, skb); 180 return true; 181 } 182 return false; 183 } 184 185 INDIRECT_CALLABLE_DECLARE(int udp_rcv(struct sk_buff *)); 186 INDIRECT_CALLABLE_DECLARE(int tcp_v4_rcv(struct sk_buff *)); 187 void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int protocol) 188 { 189 const struct net_protocol *ipprot; 190 int raw, ret; 191 192 resubmit: 193 raw = raw_local_deliver(skb, protocol); 194 195 ipprot = rcu_dereference(inet_protos[protocol]); 196 if (ipprot) { 197 if (!ipprot->no_policy) { 198 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 199 kfree_skb_reason(skb, 200 SKB_DROP_REASON_XFRM_POLICY); 201 return; 202 } 203 nf_reset_ct(skb); 204 } 205 ret = INDIRECT_CALL_2(ipprot->handler, tcp_v4_rcv, udp_rcv, 206 skb); 207 if (ret < 0) { 208 protocol = -ret; 209 goto resubmit; 210 } 211 __IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS); 212 } else { 213 if (!raw) { 214 if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 215 __IP_INC_STATS(net, IPSTATS_MIB_INUNKNOWNPROTOS); 216 icmp_send(skb, ICMP_DEST_UNREACH, 217 ICMP_PROT_UNREACH, 0); 218 } 219 kfree_skb_reason(skb, SKB_DROP_REASON_IP_NOPROTO); 220 } else { 221 __IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS); 222 consume_skb(skb); 223 } 224 } 225 } 226 227 static int ip_local_deliver_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 228 { 229 skb_clear_delivery_time(skb); 230 __skb_pull(skb, skb_network_header_len(skb)); 231 232 rcu_read_lock(); 233 ip_protocol_deliver_rcu(net, skb, ip_hdr(skb)->protocol); 234 rcu_read_unlock(); 235 236 return 0; 237 } 238 239 /* 240 * Deliver IP Packets to the higher protocol layers. 241 */ 242 int ip_local_deliver(struct sk_buff *skb) 243 { 244 /* 245 * Reassemble IP fragments. 246 */ 247 struct net *net = dev_net(skb->dev); 248 249 if (ip_is_fragment(ip_hdr(skb))) { 250 if (ip_defrag(net, skb, IP_DEFRAG_LOCAL_DELIVER)) 251 return 0; 252 } 253 254 return NF_HOOK(NFPROTO_IPV4, NF_INET_LOCAL_IN, 255 net, NULL, skb, skb->dev, NULL, 256 ip_local_deliver_finish); 257 } 258 EXPORT_SYMBOL(ip_local_deliver); 259 260 static inline bool ip_rcv_options(struct sk_buff *skb, struct net_device *dev) 261 { 262 struct ip_options *opt; 263 const struct iphdr *iph; 264 265 /* It looks as overkill, because not all 266 IP options require packet mangling. 267 But it is the easiest for now, especially taking 268 into account that combination of IP options 269 and running sniffer is extremely rare condition. 270 --ANK (980813) 271 */ 272 if (skb_cow(skb, skb_headroom(skb))) { 273 __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INDISCARDS); 274 goto drop; 275 } 276 277 iph = ip_hdr(skb); 278 opt = &(IPCB(skb)->opt); 279 opt->optlen = iph->ihl*4 - sizeof(struct iphdr); 280 281 if (ip_options_compile(dev_net(dev), opt, skb)) { 282 __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INHDRERRORS); 283 goto drop; 284 } 285 286 if (unlikely(opt->srr)) { 287 struct in_device *in_dev = __in_dev_get_rcu(dev); 288 289 if (in_dev) { 290 if (!IN_DEV_SOURCE_ROUTE(in_dev)) { 291 if (IN_DEV_LOG_MARTIANS(in_dev)) 292 net_info_ratelimited("source route option %pI4 -> %pI4\n", 293 &iph->saddr, 294 &iph->daddr); 295 goto drop; 296 } 297 } 298 299 if (ip_options_rcv_srr(skb, dev)) 300 goto drop; 301 } 302 303 return false; 304 drop: 305 return true; 306 } 307 308 static bool ip_can_use_hint(const struct sk_buff *skb, const struct iphdr *iph, 309 const struct sk_buff *hint) 310 { 311 return hint && !skb_dst(skb) && ip_hdr(hint)->daddr == iph->daddr && 312 ip_hdr(hint)->tos == iph->tos; 313 } 314 315 int tcp_v4_early_demux(struct sk_buff *skb); 316 int udp_v4_early_demux(struct sk_buff *skb); 317 static int ip_rcv_finish_core(struct net *net, struct sock *sk, 318 struct sk_buff *skb, struct net_device *dev, 319 const struct sk_buff *hint) 320 { 321 const struct iphdr *iph = ip_hdr(skb); 322 int err, drop_reason; 323 struct rtable *rt; 324 325 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 326 327 if (ip_can_use_hint(skb, iph, hint)) { 328 err = ip_route_use_hint(skb, iph->daddr, iph->saddr, iph->tos, 329 dev, hint); 330 if (unlikely(err)) 331 goto drop_error; 332 } 333 334 if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) && 335 !skb_dst(skb) && 336 !skb->sk && 337 !ip_is_fragment(iph)) { 338 switch (iph->protocol) { 339 case IPPROTO_TCP: 340 if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) { 341 tcp_v4_early_demux(skb); 342 343 /* must reload iph, skb->head might have changed */ 344 iph = ip_hdr(skb); 345 } 346 break; 347 case IPPROTO_UDP: 348 if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) { 349 err = udp_v4_early_demux(skb); 350 if (unlikely(err)) 351 goto drop_error; 352 353 /* must reload iph, skb->head might have changed */ 354 iph = ip_hdr(skb); 355 } 356 break; 357 } 358 } 359 360 /* 361 * Initialise the virtual path cache for the packet. It describes 362 * how the packet travels inside Linux networking. 363 */ 364 if (!skb_valid_dst(skb)) { 365 err = ip_route_input_noref(skb, iph->daddr, iph->saddr, 366 iph->tos, dev); 367 if (unlikely(err)) 368 goto drop_error; 369 } else { 370 struct in_device *in_dev = __in_dev_get_rcu(dev); 371 372 if (in_dev && IN_DEV_ORCONF(in_dev, NOPOLICY)) 373 IPCB(skb)->flags |= IPSKB_NOPOLICY; 374 } 375 376 #ifdef CONFIG_IP_ROUTE_CLASSID 377 if (unlikely(skb_dst(skb)->tclassid)) { 378 struct ip_rt_acct *st = this_cpu_ptr(ip_rt_acct); 379 u32 idx = skb_dst(skb)->tclassid; 380 st[idx&0xFF].o_packets++; 381 st[idx&0xFF].o_bytes += skb->len; 382 st[(idx>>16)&0xFF].i_packets++; 383 st[(idx>>16)&0xFF].i_bytes += skb->len; 384 } 385 #endif 386 387 if (iph->ihl > 5 && ip_rcv_options(skb, dev)) 388 goto drop; 389 390 rt = skb_rtable(skb); 391 if (rt->rt_type == RTN_MULTICAST) { 392 __IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len); 393 } else if (rt->rt_type == RTN_BROADCAST) { 394 __IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len); 395 } else if (skb->pkt_type == PACKET_BROADCAST || 396 skb->pkt_type == PACKET_MULTICAST) { 397 struct in_device *in_dev = __in_dev_get_rcu(dev); 398 399 /* RFC 1122 3.3.6: 400 * 401 * When a host sends a datagram to a link-layer broadcast 402 * address, the IP destination address MUST be a legal IP 403 * broadcast or IP multicast address. 404 * 405 * A host SHOULD silently discard a datagram that is received 406 * via a link-layer broadcast (see Section 2.4) but does not 407 * specify an IP multicast or broadcast destination address. 408 * 409 * This doesn't explicitly say L2 *broadcast*, but broadcast is 410 * in a way a form of multicast and the most common use case for 411 * this is 802.11 protecting against cross-station spoofing (the 412 * so-called "hole-196" attack) so do it for both. 413 */ 414 if (in_dev && 415 IN_DEV_ORCONF(in_dev, DROP_UNICAST_IN_L2_MULTICAST)) { 416 drop_reason = SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST; 417 goto drop; 418 } 419 } 420 421 return NET_RX_SUCCESS; 422 423 drop: 424 kfree_skb_reason(skb, drop_reason); 425 return NET_RX_DROP; 426 427 drop_error: 428 if (err == -EXDEV) { 429 drop_reason = SKB_DROP_REASON_IP_RPFILTER; 430 __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER); 431 } 432 goto drop; 433 } 434 435 static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 436 { 437 struct net_device *dev = skb->dev; 438 int ret; 439 440 /* if ingress device is enslaved to an L3 master device pass the 441 * skb to its handler for processing 442 */ 443 skb = l3mdev_ip_rcv(skb); 444 if (!skb) 445 return NET_RX_SUCCESS; 446 447 ret = ip_rcv_finish_core(net, sk, skb, dev, NULL); 448 if (ret != NET_RX_DROP) 449 ret = dst_input(skb); 450 return ret; 451 } 452 453 /* 454 * Main IP Receive routine. 455 */ 456 static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net) 457 { 458 const struct iphdr *iph; 459 int drop_reason; 460 u32 len; 461 462 /* When the interface is in promisc. mode, drop all the crap 463 * that it receives, do not try to analyse it. 464 */ 465 if (skb->pkt_type == PACKET_OTHERHOST) { 466 dev_core_stats_rx_otherhost_dropped_inc(skb->dev); 467 drop_reason = SKB_DROP_REASON_OTHERHOST; 468 goto drop; 469 } 470 471 __IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len); 472 473 skb = skb_share_check(skb, GFP_ATOMIC); 474 if (!skb) { 475 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); 476 goto out; 477 } 478 479 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 480 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 481 goto inhdr_error; 482 483 iph = ip_hdr(skb); 484 485 /* 486 * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum. 487 * 488 * Is the datagram acceptable? 489 * 490 * 1. Length at least the size of an ip header 491 * 2. Version of 4 492 * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums] 493 * 4. Doesn't have a bogus length 494 */ 495 496 if (iph->ihl < 5 || iph->version != 4) 497 goto inhdr_error; 498 499 BUILD_BUG_ON(IPSTATS_MIB_ECT1PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_1); 500 BUILD_BUG_ON(IPSTATS_MIB_ECT0PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_0); 501 BUILD_BUG_ON(IPSTATS_MIB_CEPKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_CE); 502 __IP_ADD_STATS(net, 503 IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK), 504 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs)); 505 506 if (!pskb_may_pull(skb, iph->ihl*4)) 507 goto inhdr_error; 508 509 iph = ip_hdr(skb); 510 511 if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) 512 goto csum_error; 513 514 len = iph_totlen(skb, iph); 515 if (skb->len < len) { 516 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; 517 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS); 518 goto drop; 519 } else if (len < (iph->ihl*4)) 520 goto inhdr_error; 521 522 /* Our transport medium may have padded the buffer out. Now we know it 523 * is IP we can trim to the true length of the frame. 524 * Note this now means skb->len holds ntohs(iph->tot_len). 525 */ 526 if (pskb_trim_rcsum(skb, len)) { 527 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); 528 goto drop; 529 } 530 531 iph = ip_hdr(skb); 532 skb->transport_header = skb->network_header + iph->ihl*4; 533 534 /* Remove any debris in the socket control block */ 535 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 536 IPCB(skb)->iif = skb->skb_iif; 537 538 /* Must drop socket now because of tproxy. */ 539 if (!skb_sk_is_prefetched(skb)) 540 skb_orphan(skb); 541 542 return skb; 543 544 csum_error: 545 drop_reason = SKB_DROP_REASON_IP_CSUM; 546 __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS); 547 inhdr_error: 548 if (drop_reason == SKB_DROP_REASON_NOT_SPECIFIED) 549 drop_reason = SKB_DROP_REASON_IP_INHDR; 550 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS); 551 drop: 552 kfree_skb_reason(skb, drop_reason); 553 out: 554 return NULL; 555 } 556 557 /* 558 * IP receive entry point 559 */ 560 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, 561 struct net_device *orig_dev) 562 { 563 struct net *net = dev_net(dev); 564 565 skb = ip_rcv_core(skb, net); 566 if (skb == NULL) 567 return NET_RX_DROP; 568 569 return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, 570 net, NULL, skb, dev, NULL, 571 ip_rcv_finish); 572 } 573 574 static void ip_sublist_rcv_finish(struct list_head *head) 575 { 576 struct sk_buff *skb, *next; 577 578 list_for_each_entry_safe(skb, next, head, list) { 579 skb_list_del_init(skb); 580 dst_input(skb); 581 } 582 } 583 584 static struct sk_buff *ip_extract_route_hint(const struct net *net, 585 struct sk_buff *skb, int rt_type) 586 { 587 if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST) 588 return NULL; 589 590 return skb; 591 } 592 593 static void ip_list_rcv_finish(struct net *net, struct sock *sk, 594 struct list_head *head) 595 { 596 struct sk_buff *skb, *next, *hint = NULL; 597 struct dst_entry *curr_dst = NULL; 598 struct list_head sublist; 599 600 INIT_LIST_HEAD(&sublist); 601 list_for_each_entry_safe(skb, next, head, list) { 602 struct net_device *dev = skb->dev; 603 struct dst_entry *dst; 604 605 skb_list_del_init(skb); 606 /* if ingress device is enslaved to an L3 master device pass the 607 * skb to its handler for processing 608 */ 609 skb = l3mdev_ip_rcv(skb); 610 if (!skb) 611 continue; 612 if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP) 613 continue; 614 615 dst = skb_dst(skb); 616 if (curr_dst != dst) { 617 hint = ip_extract_route_hint(net, skb, 618 ((struct rtable *)dst)->rt_type); 619 620 /* dispatch old sublist */ 621 if (!list_empty(&sublist)) 622 ip_sublist_rcv_finish(&sublist); 623 /* start new sublist */ 624 INIT_LIST_HEAD(&sublist); 625 curr_dst = dst; 626 } 627 list_add_tail(&skb->list, &sublist); 628 } 629 /* dispatch final sublist */ 630 ip_sublist_rcv_finish(&sublist); 631 } 632 633 static void ip_sublist_rcv(struct list_head *head, struct net_device *dev, 634 struct net *net) 635 { 636 NF_HOOK_LIST(NFPROTO_IPV4, NF_INET_PRE_ROUTING, net, NULL, 637 head, dev, NULL, ip_rcv_finish); 638 ip_list_rcv_finish(net, NULL, head); 639 } 640 641 /* Receive a list of IP packets */ 642 void ip_list_rcv(struct list_head *head, struct packet_type *pt, 643 struct net_device *orig_dev) 644 { 645 struct net_device *curr_dev = NULL; 646 struct net *curr_net = NULL; 647 struct sk_buff *skb, *next; 648 struct list_head sublist; 649 650 INIT_LIST_HEAD(&sublist); 651 list_for_each_entry_safe(skb, next, head, list) { 652 struct net_device *dev = skb->dev; 653 struct net *net = dev_net(dev); 654 655 skb_list_del_init(skb); 656 skb = ip_rcv_core(skb, net); 657 if (skb == NULL) 658 continue; 659 660 if (curr_dev != dev || curr_net != net) { 661 /* dispatch old sublist */ 662 if (!list_empty(&sublist)) 663 ip_sublist_rcv(&sublist, curr_dev, curr_net); 664 /* start new sublist */ 665 INIT_LIST_HEAD(&sublist); 666 curr_dev = dev; 667 curr_net = net; 668 } 669 list_add_tail(&skb->list, &sublist); 670 } 671 /* dispatch final sublist */ 672 if (!list_empty(&sublist)) 673 ip_sublist_rcv(&sublist, curr_dev, curr_net); 674 } 675