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#ifdef CONFIG_LOWPOWER_PROTOCOL 145#include <net/lowpower_protocol.h> 146#endif /* CONFIG_LOWPOWER_PROTOCOL */ 147 148/* 149 * Process Router Attention IP option (RFC 2113) 150 */ 151bool ip_call_ra_chain(struct sk_buff *skb) 152{ 153 struct ip_ra_chain *ra; 154 u8 protocol = ip_hdr(skb)->protocol; 155 struct sock *last = NULL; 156 struct net_device *dev = skb->dev; 157 struct net *net = dev_net(dev); 158 159 for (ra = rcu_dereference(net->ipv4.ra_chain); ra; ra = rcu_dereference(ra->next)) { 160 struct sock *sk = ra->sk; 161 162 /* If socket is bound to an interface, only report 163 * the packet if it came from that interface. 164 */ 165 if (sk && inet_sk(sk)->inet_num == protocol && 166 (!sk->sk_bound_dev_if || 167 sk->sk_bound_dev_if == dev->ifindex)) { 168 if (ip_is_fragment(ip_hdr(skb))) { 169 if (ip_defrag(net, skb, IP_DEFRAG_CALL_RA_CHAIN)) 170 return true; 171 } 172 if (last) { 173 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); 174 if (skb2) 175 raw_rcv(last, skb2); 176 } 177 last = sk; 178 } 179 } 180 181 if (last) { 182 raw_rcv(last, skb); 183 return true; 184 } 185 return false; 186} 187 188INDIRECT_CALLABLE_DECLARE(int udp_rcv(struct sk_buff *)); 189INDIRECT_CALLABLE_DECLARE(int tcp_v4_rcv(struct sk_buff *)); 190void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int protocol) 191{ 192 const struct net_protocol *ipprot; 193 int raw, ret; 194 195resubmit: 196 raw = raw_local_deliver(skb, protocol); 197 198 ipprot = rcu_dereference(inet_protos[protocol]); 199 if (ipprot) { 200 if (!ipprot->no_policy) { 201 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 202 kfree_skb(skb); 203 return; 204 } 205 nf_reset_ct(skb); 206 } 207 ret = INDIRECT_CALL_2(ipprot->handler, tcp_v4_rcv, udp_rcv, 208 skb); 209 if (ret < 0) { 210 protocol = -ret; 211 goto resubmit; 212 } 213 __IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS); 214 } else { 215 if (!raw) { 216 if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { 217 __IP_INC_STATS(net, IPSTATS_MIB_INUNKNOWNPROTOS); 218 icmp_send(skb, ICMP_DEST_UNREACH, 219 ICMP_PROT_UNREACH, 0); 220 } 221 kfree_skb(skb); 222 } else { 223 __IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS); 224 consume_skb(skb); 225 } 226 } 227} 228 229static int ip_local_deliver_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 230{ 231 __skb_pull(skb, skb_network_header_len(skb)); 232 233 rcu_read_lock(); 234 ip_protocol_deliver_rcu(net, skb, ip_hdr(skb)->protocol); 235 rcu_read_unlock(); 236 237 return 0; 238} 239 240/* 241 * Deliver IP Packets to the higher protocol layers. 242 */ 243int ip_local_deliver(struct sk_buff *skb) 244{ 245 /* 246 * Reassemble IP fragments. 247 */ 248 struct net *net = dev_net(skb->dev); 249#ifdef CONFIG_LOWPOWER_PROTOCOL 250 int ret; 251#endif /* CONFIG_LOWPOWER_PROTOCOL */ 252 253 if (ip_is_fragment(ip_hdr(skb))) { 254 if (ip_defrag(net, skb, IP_DEFRAG_LOCAL_DELIVER)) 255 return 0; 256 } 257 258#ifdef CONFIG_LOWPOWER_PROTOCOL 259 if (netfilter_bypass_enable(net, skb, ip_local_deliver_finish, &ret)) 260 return ret; 261#endif /* CONFIG_LOWPOWER_PROTOCOL */ 262 263 return NF_HOOK(NFPROTO_IPV4, NF_INET_LOCAL_IN, 264 net, NULL, skb, skb->dev, NULL, 265 ip_local_deliver_finish); 266} 267 268static inline bool ip_rcv_options(struct sk_buff *skb, struct net_device *dev) 269{ 270 struct ip_options *opt; 271 const struct iphdr *iph; 272 273 /* It looks as overkill, because not all 274 IP options require packet mangling. 275 But it is the easiest for now, especially taking 276 into account that combination of IP options 277 and running sniffer is extremely rare condition. 278 --ANK (980813) 279 */ 280 if (skb_cow(skb, skb_headroom(skb))) { 281 __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INDISCARDS); 282 goto drop; 283 } 284 285 iph = ip_hdr(skb); 286 opt = &(IPCB(skb)->opt); 287 opt->optlen = iph->ihl*4 - sizeof(struct iphdr); 288 289 if (ip_options_compile(dev_net(dev), opt, skb)) { 290 __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INHDRERRORS); 291 goto drop; 292 } 293 294 if (unlikely(opt->srr)) { 295 struct in_device *in_dev = __in_dev_get_rcu(dev); 296 297 if (in_dev) { 298 if (!IN_DEV_SOURCE_ROUTE(in_dev)) { 299 if (IN_DEV_LOG_MARTIANS(in_dev)) 300 net_info_ratelimited("source route option %pI4 -> %pI4\n", 301 &iph->saddr, 302 &iph->daddr); 303 goto drop; 304 } 305 } 306 307 if (ip_options_rcv_srr(skb, dev)) 308 goto drop; 309 } 310 311 return false; 312drop: 313 return true; 314} 315 316static bool ip_can_use_hint(const struct sk_buff *skb, const struct iphdr *iph, 317 const struct sk_buff *hint) 318{ 319 return hint && !skb_dst(skb) && ip_hdr(hint)->daddr == iph->daddr && 320 ip_hdr(hint)->tos == iph->tos; 321} 322 323int tcp_v4_early_demux(struct sk_buff *skb); 324int udp_v4_early_demux(struct sk_buff *skb); 325static int ip_rcv_finish_core(struct net *net, struct sock *sk, 326 struct sk_buff *skb, struct net_device *dev, 327 const struct sk_buff *hint) 328{ 329 const struct iphdr *iph = ip_hdr(skb); 330 struct rtable *rt; 331 int err; 332 333 if (ip_can_use_hint(skb, iph, hint)) { 334 err = ip_route_use_hint(skb, iph->daddr, iph->saddr, iph->tos, 335 dev, hint); 336 if (unlikely(err)) 337 goto drop_error; 338 } 339 340 if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) && 341 !skb_dst(skb) && 342 !skb->sk && 343 !ip_is_fragment(iph)) { 344 switch (iph->protocol) { 345 case IPPROTO_TCP: 346 if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) { 347 tcp_v4_early_demux(skb); 348 349 /* must reload iph, skb->head might have changed */ 350 iph = ip_hdr(skb); 351 } 352 break; 353 case IPPROTO_UDP: 354 if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) { 355 err = udp_v4_early_demux(skb); 356 if (unlikely(err)) 357 goto drop_error; 358 359 /* must reload iph, skb->head might have changed */ 360 iph = ip_hdr(skb); 361 } 362 break; 363 } 364 } 365 366 /* 367 * Initialise the virtual path cache for the packet. It describes 368 * how the packet travels inside Linux networking. 369 */ 370 if (!skb_valid_dst(skb)) { 371 err = ip_route_input_noref(skb, iph->daddr, iph->saddr, 372 iph->tos, dev); 373 if (unlikely(err)) 374 goto drop_error; 375 } else { 376 struct in_device *in_dev = __in_dev_get_rcu(dev); 377 378 if (in_dev && IN_DEV_ORCONF(in_dev, NOPOLICY)) 379 IPCB(skb)->flags |= IPSKB_NOPOLICY; 380 } 381 382#ifdef CONFIG_IP_ROUTE_CLASSID 383 if (unlikely(skb_dst(skb)->tclassid)) { 384 struct ip_rt_acct *st = this_cpu_ptr(ip_rt_acct); 385 u32 idx = skb_dst(skb)->tclassid; 386 st[idx&0xFF].o_packets++; 387 st[idx&0xFF].o_bytes += skb->len; 388 st[(idx>>16)&0xFF].i_packets++; 389 st[(idx>>16)&0xFF].i_bytes += skb->len; 390 } 391#endif 392 393 if (iph->ihl > 5 && ip_rcv_options(skb, dev)) 394 goto drop; 395 396 rt = skb_rtable(skb); 397 if (rt->rt_type == RTN_MULTICAST) { 398 __IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len); 399 } else if (rt->rt_type == RTN_BROADCAST) { 400 __IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len); 401 } else if (skb->pkt_type == PACKET_BROADCAST || 402 skb->pkt_type == PACKET_MULTICAST) { 403 struct in_device *in_dev = __in_dev_get_rcu(dev); 404 405 /* RFC 1122 3.3.6: 406 * 407 * When a host sends a datagram to a link-layer broadcast 408 * address, the IP destination address MUST be a legal IP 409 * broadcast or IP multicast address. 410 * 411 * A host SHOULD silently discard a datagram that is received 412 * via a link-layer broadcast (see Section 2.4) but does not 413 * specify an IP multicast or broadcast destination address. 414 * 415 * This doesn't explicitly say L2 *broadcast*, but broadcast is 416 * in a way a form of multicast and the most common use case for 417 * this is 802.11 protecting against cross-station spoofing (the 418 * so-called "hole-196" attack) so do it for both. 419 */ 420 if (in_dev && 421 IN_DEV_ORCONF(in_dev, DROP_UNICAST_IN_L2_MULTICAST)) 422 goto drop; 423 } 424 425 return NET_RX_SUCCESS; 426 427drop: 428 kfree_skb(skb); 429 return NET_RX_DROP; 430 431drop_error: 432 if (err == -EXDEV) 433 __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER); 434 goto drop; 435} 436 437static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) 438{ 439 struct net_device *dev = skb->dev; 440 int ret; 441 442 /* if ingress device is enslaved to an L3 master device pass the 443 * skb to its handler for processing 444 */ 445 skb = l3mdev_ip_rcv(skb); 446 if (!skb) 447 return NET_RX_SUCCESS; 448 449 ret = ip_rcv_finish_core(net, sk, skb, dev, NULL); 450 if (ret != NET_RX_DROP) 451 ret = dst_input(skb); 452 return ret; 453} 454 455/* 456 * Main IP Receive routine. 457 */ 458static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net) 459{ 460 const struct iphdr *iph; 461 u32 len; 462 463 /* When the interface is in promisc. mode, drop all the crap 464 * that it receives, do not try to analyse it. 465 */ 466 if (skb->pkt_type == PACKET_OTHERHOST) 467 goto drop; 468 469 __IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len); 470 471 skb = skb_share_check(skb, GFP_ATOMIC); 472 if (!skb) { 473 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); 474 goto out; 475 } 476 477 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 478 goto inhdr_error; 479 480 iph = ip_hdr(skb); 481 482 /* 483 * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum. 484 * 485 * Is the datagram acceptable? 486 * 487 * 1. Length at least the size of an ip header 488 * 2. Version of 4 489 * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums] 490 * 4. Doesn't have a bogus length 491 */ 492 493 if (iph->ihl < 5 || iph->version != 4) 494 goto inhdr_error; 495 496 BUILD_BUG_ON(IPSTATS_MIB_ECT1PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_1); 497 BUILD_BUG_ON(IPSTATS_MIB_ECT0PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_0); 498 BUILD_BUG_ON(IPSTATS_MIB_CEPKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_CE); 499 __IP_ADD_STATS(net, 500 IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK), 501 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs)); 502 503 if (!pskb_may_pull(skb, iph->ihl*4)) 504 goto inhdr_error; 505 506 iph = ip_hdr(skb); 507 508 if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) 509 goto csum_error; 510 511 len = ntohs(iph->tot_len); 512 if (skb->len < len) { 513 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS); 514 goto drop; 515 } else if (len < (iph->ihl*4)) 516 goto inhdr_error; 517 518 /* Our transport medium may have padded the buffer out. Now we know it 519 * is IP we can trim to the true length of the frame. 520 * Note this now means skb->len holds ntohs(iph->tot_len). 521 */ 522 if (pskb_trim_rcsum(skb, len)) { 523 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); 524 goto drop; 525 } 526 527 iph = ip_hdr(skb); 528 skb->transport_header = skb->network_header + iph->ihl*4; 529 530 /* Remove any debris in the socket control block */ 531 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 532 IPCB(skb)->iif = skb->skb_iif; 533 534 /* Must drop socket now because of tproxy. */ 535 if (!skb_sk_is_prefetched(skb)) 536 skb_orphan(skb); 537 538 return skb; 539 540csum_error: 541 __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS); 542inhdr_error: 543 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS); 544drop: 545 kfree_skb(skb); 546out: 547 return NULL; 548} 549 550/* 551 * IP receive entry point 552 */ 553int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, 554 struct net_device *orig_dev) 555{ 556 struct net *net = dev_net(dev); 557 558 skb = ip_rcv_core(skb, net); 559 if (skb == NULL) 560 return NET_RX_DROP; 561 562 return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, 563 net, NULL, skb, dev, NULL, 564 ip_rcv_finish); 565} 566 567static void ip_sublist_rcv_finish(struct list_head *head) 568{ 569 struct sk_buff *skb, *next; 570 571 list_for_each_entry_safe(skb, next, head, list) { 572 skb_list_del_init(skb); 573 dst_input(skb); 574 } 575} 576 577static struct sk_buff *ip_extract_route_hint(const struct net *net, 578 struct sk_buff *skb, int rt_type) 579{ 580 if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST || 581 IPCB(skb)->flags & IPSKB_MULTIPATH) 582 return NULL; 583 584 return skb; 585} 586 587static void ip_list_rcv_finish(struct net *net, struct sock *sk, 588 struct list_head *head) 589{ 590 struct sk_buff *skb, *next, *hint = NULL; 591 struct dst_entry *curr_dst = NULL; 592 struct list_head sublist; 593 594 INIT_LIST_HEAD(&sublist); 595 list_for_each_entry_safe(skb, next, head, list) { 596 struct net_device *dev = skb->dev; 597 struct dst_entry *dst; 598 599 skb_list_del_init(skb); 600 /* if ingress device is enslaved to an L3 master device pass the 601 * skb to its handler for processing 602 */ 603 skb = l3mdev_ip_rcv(skb); 604 if (!skb) 605 continue; 606 if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP) 607 continue; 608 609 dst = skb_dst(skb); 610 if (curr_dst != dst) { 611 hint = ip_extract_route_hint(net, skb, 612 ((struct rtable *)dst)->rt_type); 613 614 /* dispatch old sublist */ 615 if (!list_empty(&sublist)) 616 ip_sublist_rcv_finish(&sublist); 617 /* start new sublist */ 618 INIT_LIST_HEAD(&sublist); 619 curr_dst = dst; 620 } 621 list_add_tail(&skb->list, &sublist); 622 } 623 /* dispatch final sublist */ 624 ip_sublist_rcv_finish(&sublist); 625} 626 627static void ip_sublist_rcv(struct list_head *head, struct net_device *dev, 628 struct net *net) 629{ 630 NF_HOOK_LIST(NFPROTO_IPV4, NF_INET_PRE_ROUTING, net, NULL, 631 head, dev, NULL, ip_rcv_finish); 632 ip_list_rcv_finish(net, NULL, head); 633} 634 635/* Receive a list of IP packets */ 636void ip_list_rcv(struct list_head *head, struct packet_type *pt, 637 struct net_device *orig_dev) 638{ 639 struct net_device *curr_dev = NULL; 640 struct net *curr_net = NULL; 641 struct sk_buff *skb, *next; 642 struct list_head sublist; 643 644 INIT_LIST_HEAD(&sublist); 645 list_for_each_entry_safe(skb, next, head, list) { 646 struct net_device *dev = skb->dev; 647 struct net *net = dev_net(dev); 648 649 skb_list_del_init(skb); 650 skb = ip_rcv_core(skb, net); 651 if (skb == NULL) 652 continue; 653 654 if (curr_dev != dev || curr_net != net) { 655 /* dispatch old sublist */ 656 if (!list_empty(&sublist)) 657 ip_sublist_rcv(&sublist, curr_dev, curr_net); 658 /* start new sublist */ 659 INIT_LIST_HEAD(&sublist); 660 curr_dev = dev; 661 curr_net = net; 662 } 663 list_add_tail(&skb->list, &sublist); 664 } 665 /* dispatch final sublist */ 666 if (!list_empty(&sublist)) 667 ip_sublist_rcv(&sublist, curr_dev, curr_net); 668} 669