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 } 370 371 #ifdef CONFIG_IP_ROUTE_CLASSID 372 if (unlikely(skb_dst(skb)->tclassid)) { 373 struct ip_rt_acct *st = this_cpu_ptr(ip_rt_acct); 374 u32 idx = skb_dst(skb)->tclassid; 375 st[idx&0xFF].o_packets++; 376 st[idx&0xFF].o_bytes += skb->len; 377 st[(idx>>16)&0xFF].i_packets++; 378 st[(idx>>16)&0xFF].i_bytes += skb->len; 379 } 380 #endif 381 382 if (iph->ihl > 5 && ip_rcv_options(skb, dev)) 383 goto drop; 384 385 rt = skb_rtable(skb); 386 if (rt->rt_type == RTN_MULTICAST) { 387 __IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len); 388 } else if (rt->rt_type == RTN_BROADCAST) { 389 __IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len); 390 } else if (skb->pkt_type == PACKET_BROADCAST || 391 skb->pkt_type == PACKET_MULTICAST) { 392 struct in_device *in_dev = __in_dev_get_rcu(dev); 393 394 /* RFC 1122 3.3.6: 395 * 396 * When a host sends a datagram to a link-layer broadcast 397 * address, the IP destination address MUST be a legal IP 398 * broadcast or IP multicast address. 399 * 400 * A host SHOULD silently discard a datagram that is received 401 * via a link-layer broadcast (see Section 2.4) but does not 402 * specify an IP multicast or broadcast destination address. 403 * 404 * This doesn't explicitly say L2 *broadcast*, but broadcast is 405 * in a way a form of multicast and the most common use case for 406 * this is 802.11 protecting against cross-station spoofing (the 407 * so-called "hole-196" attack) so do it for both. 408 */ 409 if (in_dev && 410 IN_DEV_ORCONF(in_dev, DROP_UNICAST_IN_L2_MULTICAST)) { 411 drop_reason = SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST; 412 goto drop; 413 } 414 } 415 416 return NET_RX_SUCCESS; 417 418 drop: 419 kfree_skb_reason(skb, drop_reason); 420 return NET_RX_DROP; 421 422 drop_error: 423 if (err == -EXDEV) { 424 drop_reason = SKB_DROP_REASON_IP_RPFILTER; 425 __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER); 426 } 427 goto drop; 428 } 429 430 static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 431 { 432 struct net_device *dev = skb->dev; 433 int ret; 434 435 /* if ingress device is enslaved to an L3 master device pass the 436 * skb to its handler for processing 437 */ 438 skb = l3mdev_ip_rcv(skb); 439 if (!skb) 440 return NET_RX_SUCCESS; 441 442 ret = ip_rcv_finish_core(net, sk, skb, dev, NULL); 443 if (ret != NET_RX_DROP) 444 ret = dst_input(skb); 445 return ret; 446 } 447 448 /* 449 * Main IP Receive routine. 450 */ 451 static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net) 452 { 453 const struct iphdr *iph; 454 int drop_reason; 455 u32 len; 456 457 /* When the interface is in promisc. mode, drop all the crap 458 * that it receives, do not try to analyse it. 459 */ 460 if (skb->pkt_type == PACKET_OTHERHOST) { 461 dev_core_stats_rx_otherhost_dropped_inc(skb->dev); 462 drop_reason = SKB_DROP_REASON_OTHERHOST; 463 goto drop; 464 } 465 466 __IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len); 467 468 skb = skb_share_check(skb, GFP_ATOMIC); 469 if (!skb) { 470 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); 471 goto out; 472 } 473 474 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; 475 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 476 goto inhdr_error; 477 478 iph = ip_hdr(skb); 479 480 /* 481 * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum. 482 * 483 * Is the datagram acceptable? 484 * 485 * 1. Length at least the size of an ip header 486 * 2. Version of 4 487 * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums] 488 * 4. Doesn't have a bogus length 489 */ 490 491 if (iph->ihl < 5 || iph->version != 4) 492 goto inhdr_error; 493 494 BUILD_BUG_ON(IPSTATS_MIB_ECT1PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_1); 495 BUILD_BUG_ON(IPSTATS_MIB_ECT0PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_0); 496 BUILD_BUG_ON(IPSTATS_MIB_CEPKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_CE); 497 __IP_ADD_STATS(net, 498 IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK), 499 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs)); 500 501 if (!pskb_may_pull(skb, iph->ihl*4)) 502 goto inhdr_error; 503 504 iph = ip_hdr(skb); 505 506 if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) 507 goto csum_error; 508 509 len = ntohs(iph->tot_len); 510 if (skb->len < len) { 511 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; 512 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS); 513 goto drop; 514 } else if (len < (iph->ihl*4)) 515 goto inhdr_error; 516 517 /* Our transport medium may have padded the buffer out. Now we know it 518 * is IP we can trim to the true length of the frame. 519 * Note this now means skb->len holds ntohs(iph->tot_len). 520 */ 521 if (pskb_trim_rcsum(skb, len)) { 522 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); 523 goto drop; 524 } 525 526 iph = ip_hdr(skb); 527 skb->transport_header = skb->network_header + iph->ihl*4; 528 529 /* Remove any debris in the socket control block */ 530 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 531 IPCB(skb)->iif = skb->skb_iif; 532 533 /* Must drop socket now because of tproxy. */ 534 if (!skb_sk_is_prefetched(skb)) 535 skb_orphan(skb); 536 537 return skb; 538 539 csum_error: 540 drop_reason = SKB_DROP_REASON_IP_CSUM; 541 __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS); 542 inhdr_error: 543 if (drop_reason == SKB_DROP_REASON_NOT_SPECIFIED) 544 drop_reason = SKB_DROP_REASON_IP_INHDR; 545 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS); 546 drop: 547 kfree_skb_reason(skb, drop_reason); 548 out: 549 return NULL; 550 } 551 552 /* 553 * IP receive entry point 554 */ 555 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, 556 struct net_device *orig_dev) 557 { 558 struct net *net = dev_net(dev); 559 560 skb = ip_rcv_core(skb, net); 561 if (skb == NULL) 562 return NET_RX_DROP; 563 564 return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, 565 net, NULL, skb, dev, NULL, 566 ip_rcv_finish); 567 } 568 569 static void ip_sublist_rcv_finish(struct list_head *head) 570 { 571 struct sk_buff *skb, *next; 572 573 list_for_each_entry_safe(skb, next, head, list) { 574 skb_list_del_init(skb); 575 dst_input(skb); 576 } 577 } 578 579 static struct sk_buff *ip_extract_route_hint(const struct net *net, 580 struct sk_buff *skb, int rt_type) 581 { 582 if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST) 583 return NULL; 584 585 return skb; 586 } 587 588 static void ip_list_rcv_finish(struct net *net, struct sock *sk, 589 struct list_head *head) 590 { 591 struct sk_buff *skb, *next, *hint = NULL; 592 struct dst_entry *curr_dst = NULL; 593 struct list_head sublist; 594 595 INIT_LIST_HEAD(&sublist); 596 list_for_each_entry_safe(skb, next, head, list) { 597 struct net_device *dev = skb->dev; 598 struct dst_entry *dst; 599 600 skb_list_del_init(skb); 601 /* if ingress device is enslaved to an L3 master device pass the 602 * skb to its handler for processing 603 */ 604 skb = l3mdev_ip_rcv(skb); 605 if (!skb) 606 continue; 607 if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP) 608 continue; 609 610 dst = skb_dst(skb); 611 if (curr_dst != dst) { 612 hint = ip_extract_route_hint(net, skb, 613 ((struct rtable *)dst)->rt_type); 614 615 /* dispatch old sublist */ 616 if (!list_empty(&sublist)) 617 ip_sublist_rcv_finish(&sublist); 618 /* start new sublist */ 619 INIT_LIST_HEAD(&sublist); 620 curr_dst = dst; 621 } 622 list_add_tail(&skb->list, &sublist); 623 } 624 /* dispatch final sublist */ 625 ip_sublist_rcv_finish(&sublist); 626 } 627 628 static void ip_sublist_rcv(struct list_head *head, struct net_device *dev, 629 struct net *net) 630 { 631 NF_HOOK_LIST(NFPROTO_IPV4, NF_INET_PRE_ROUTING, net, NULL, 632 head, dev, NULL, ip_rcv_finish); 633 ip_list_rcv_finish(net, NULL, head); 634 } 635 636 /* Receive a list of IP packets */ 637 void ip_list_rcv(struct list_head *head, struct packet_type *pt, 638 struct net_device *orig_dev) 639 { 640 struct net_device *curr_dev = NULL; 641 struct net *curr_net = NULL; 642 struct sk_buff *skb, *next; 643 struct list_head sublist; 644 645 INIT_LIST_HEAD(&sublist); 646 list_for_each_entry_safe(skb, next, head, list) { 647 struct net_device *dev = skb->dev; 648 struct net *net = dev_net(dev); 649 650 skb_list_del_init(skb); 651 skb = ip_rcv_core(skb, net); 652 if (skb == NULL) 653 continue; 654 655 if (curr_dev != dev || curr_net != net) { 656 /* dispatch old sublist */ 657 if (!list_empty(&sublist)) 658 ip_sublist_rcv(&sublist, curr_dev, curr_net); 659 /* start new sublist */ 660 INIT_LIST_HEAD(&sublist); 661 curr_dev = dev; 662 curr_net = net; 663 } 664 list_add_tail(&skb->list, &sublist); 665 } 666 /* dispatch final sublist */ 667 if (!list_empty(&sublist)) 668 ip_sublist_rcv(&sublist, curr_dev, curr_net); 669 } 670