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 } else {
365 struct in_device *in_dev = __in_dev_get_rcu(dev);
366
367 if (in_dev && IN_DEV_ORCONF(in_dev, NOPOLICY))
368 IPCB(skb)->flags |= IPSKB_NOPOLICY;
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 goto drop;
412 }
413
414 return NET_RX_SUCCESS;
415
416 drop:
417 kfree_skb(skb);
418 return NET_RX_DROP;
419
420 drop_error:
421 if (err == -EXDEV)
422 __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER);
423 goto drop;
424 }
425
ip_rcv_finish(struct net * net,struct sock * sk,struct sk_buff * skb)426 static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
427 {
428 struct net_device *dev = skb->dev;
429 int ret;
430
431 /* if ingress device is enslaved to an L3 master device pass the
432 * skb to its handler for processing
433 */
434 skb = l3mdev_ip_rcv(skb);
435 if (!skb)
436 return NET_RX_SUCCESS;
437
438 ret = ip_rcv_finish_core(net, sk, skb, dev, NULL);
439 if (ret != NET_RX_DROP)
440 ret = dst_input(skb);
441 return ret;
442 }
443
444 /*
445 * Main IP Receive routine.
446 */
ip_rcv_core(struct sk_buff * skb,struct net * net)447 static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
448 {
449 const struct iphdr *iph;
450 u32 len;
451
452 /* When the interface is in promisc. mode, drop all the crap
453 * that it receives, do not try to analyse it.
454 */
455 if (skb->pkt_type == PACKET_OTHERHOST)
456 goto drop;
457
458 __IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len);
459
460 skb = skb_share_check(skb, GFP_ATOMIC);
461 if (!skb) {
462 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
463 goto out;
464 }
465
466 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
467 goto inhdr_error;
468
469 iph = ip_hdr(skb);
470
471 /*
472 * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum.
473 *
474 * Is the datagram acceptable?
475 *
476 * 1. Length at least the size of an ip header
477 * 2. Version of 4
478 * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums]
479 * 4. Doesn't have a bogus length
480 */
481
482 if (iph->ihl < 5 || iph->version != 4)
483 goto inhdr_error;
484
485 BUILD_BUG_ON(IPSTATS_MIB_ECT1PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_1);
486 BUILD_BUG_ON(IPSTATS_MIB_ECT0PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_0);
487 BUILD_BUG_ON(IPSTATS_MIB_CEPKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_CE);
488 __IP_ADD_STATS(net,
489 IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK),
490 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
491
492 if (!pskb_may_pull(skb, iph->ihl*4))
493 goto inhdr_error;
494
495 iph = ip_hdr(skb);
496
497 if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
498 goto csum_error;
499
500 len = ntohs(iph->tot_len);
501 if (skb->len < len) {
502 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
503 goto drop;
504 } else if (len < (iph->ihl*4))
505 goto inhdr_error;
506
507 /* Our transport medium may have padded the buffer out. Now we know it
508 * is IP we can trim to the true length of the frame.
509 * Note this now means skb->len holds ntohs(iph->tot_len).
510 */
511 if (pskb_trim_rcsum(skb, len)) {
512 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
513 goto drop;
514 }
515
516 iph = ip_hdr(skb);
517 skb->transport_header = skb->network_header + iph->ihl*4;
518
519 /* Remove any debris in the socket control block */
520 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
521 IPCB(skb)->iif = skb->skb_iif;
522
523 /* Must drop socket now because of tproxy. */
524 if (!skb_sk_is_prefetched(skb))
525 skb_orphan(skb);
526
527 return skb;
528
529 csum_error:
530 __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
531 inhdr_error:
532 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
533 drop:
534 kfree_skb(skb);
535 out:
536 return NULL;
537 }
538
539 /*
540 * IP receive entry point
541 */
ip_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)542 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
543 struct net_device *orig_dev)
544 {
545 struct net *net = dev_net(dev);
546
547 skb = ip_rcv_core(skb, net);
548 if (skb == NULL)
549 return NET_RX_DROP;
550
551 return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
552 net, NULL, skb, dev, NULL,
553 ip_rcv_finish);
554 }
555
ip_sublist_rcv_finish(struct list_head * head)556 static void ip_sublist_rcv_finish(struct list_head *head)
557 {
558 struct sk_buff *skb, *next;
559
560 list_for_each_entry_safe(skb, next, head, list) {
561 skb_list_del_init(skb);
562 dst_input(skb);
563 }
564 }
565
ip_extract_route_hint(const struct net * net,struct sk_buff * skb,int rt_type)566 static struct sk_buff *ip_extract_route_hint(const struct net *net,
567 struct sk_buff *skb, int rt_type)
568 {
569 if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST)
570 return NULL;
571
572 return skb;
573 }
574
ip_list_rcv_finish(struct net * net,struct sock * sk,struct list_head * head)575 static void ip_list_rcv_finish(struct net *net, struct sock *sk,
576 struct list_head *head)
577 {
578 struct sk_buff *skb, *next, *hint = NULL;
579 struct dst_entry *curr_dst = NULL;
580 struct list_head sublist;
581
582 INIT_LIST_HEAD(&sublist);
583 list_for_each_entry_safe(skb, next, head, list) {
584 struct net_device *dev = skb->dev;
585 struct dst_entry *dst;
586
587 skb_list_del_init(skb);
588 /* if ingress device is enslaved to an L3 master device pass the
589 * skb to its handler for processing
590 */
591 skb = l3mdev_ip_rcv(skb);
592 if (!skb)
593 continue;
594 if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP)
595 continue;
596
597 dst = skb_dst(skb);
598 if (curr_dst != dst) {
599 hint = ip_extract_route_hint(net, skb,
600 ((struct rtable *)dst)->rt_type);
601
602 /* dispatch old sublist */
603 if (!list_empty(&sublist))
604 ip_sublist_rcv_finish(&sublist);
605 /* start new sublist */
606 INIT_LIST_HEAD(&sublist);
607 curr_dst = dst;
608 }
609 list_add_tail(&skb->list, &sublist);
610 }
611 /* dispatch final sublist */
612 ip_sublist_rcv_finish(&sublist);
613 }
614
ip_sublist_rcv(struct list_head * head,struct net_device * dev,struct net * net)615 static void ip_sublist_rcv(struct list_head *head, struct net_device *dev,
616 struct net *net)
617 {
618 NF_HOOK_LIST(NFPROTO_IPV4, NF_INET_PRE_ROUTING, net, NULL,
619 head, dev, NULL, ip_rcv_finish);
620 ip_list_rcv_finish(net, NULL, head);
621 }
622
623 /* Receive a list of IP packets */
ip_list_rcv(struct list_head * head,struct packet_type * pt,struct net_device * orig_dev)624 void ip_list_rcv(struct list_head *head, struct packet_type *pt,
625 struct net_device *orig_dev)
626 {
627 struct net_device *curr_dev = NULL;
628 struct net *curr_net = NULL;
629 struct sk_buff *skb, *next;
630 struct list_head sublist;
631
632 INIT_LIST_HEAD(&sublist);
633 list_for_each_entry_safe(skb, next, head, list) {
634 struct net_device *dev = skb->dev;
635 struct net *net = dev_net(dev);
636
637 skb_list_del_init(skb);
638 skb = ip_rcv_core(skb, net);
639 if (skb == NULL)
640 continue;
641
642 if (curr_dev != dev || curr_net != net) {
643 /* dispatch old sublist */
644 if (!list_empty(&sublist))
645 ip_sublist_rcv(&sublist, curr_dev, curr_net);
646 /* start new sublist */
647 INIT_LIST_HEAD(&sublist);
648 curr_dev = dev;
649 curr_net = net;
650 }
651 list_add_tail(&skb->list, &sublist);
652 }
653 /* dispatch final sublist */
654 if (!list_empty(&sublist))
655 ip_sublist_rcv(&sublist, curr_dev, curr_net);
656 }
657