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