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 */
ip_call_ra_chain(struct sk_buff * skb)151 bool 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
188 INDIRECT_CALLABLE_DECLARE(int udp_rcv(struct sk_buff *));
189 INDIRECT_CALLABLE_DECLARE(int tcp_v4_rcv(struct sk_buff *));
ip_protocol_deliver_rcu(struct net * net,struct sk_buff * skb,int protocol)190 void 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
195 resubmit:
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
ip_local_deliver_finish(struct net * net,struct sock * sk,struct sk_buff * skb)229 static 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 */
ip_local_deliver(struct sk_buff * skb)243 int 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
ip_rcv_options(struct sk_buff * skb,struct net_device * dev)268 static 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;
312 drop:
313 return true;
314 }
315
ip_can_use_hint(const struct sk_buff * skb,const struct iphdr * iph,const struct sk_buff * hint)316 static 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
323 int tcp_v4_early_demux(struct sk_buff *skb);
324 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)325 static 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
427 drop:
428 kfree_skb(skb);
429 return NET_RX_DROP;
430
431 drop_error:
432 if (err == -EXDEV)
433 __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER);
434 goto drop;
435 }
436
ip_rcv_finish(struct net * net,struct sock * sk,struct sk_buff * skb)437 static 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 */
ip_rcv_core(struct sk_buff * skb,struct net * net)458 static 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
540 csum_error:
541 __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
542 inhdr_error:
543 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
544 drop:
545 kfree_skb(skb);
546 out:
547 return NULL;
548 }
549
550 /*
551 * IP receive entry point
552 */
ip_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)553 int 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
ip_sublist_rcv_finish(struct list_head * head)567 static 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
ip_extract_route_hint(const struct net * net,struct sk_buff * skb,int rt_type)577 static 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 return NULL;
582
583 return skb;
584 }
585
ip_list_rcv_finish(struct net * net,struct sock * sk,struct list_head * head)586 static void ip_list_rcv_finish(struct net *net, struct sock *sk,
587 struct list_head *head)
588 {
589 struct sk_buff *skb, *next, *hint = NULL;
590 struct dst_entry *curr_dst = NULL;
591 struct list_head sublist;
592
593 INIT_LIST_HEAD(&sublist);
594 list_for_each_entry_safe(skb, next, head, list) {
595 struct net_device *dev = skb->dev;
596 struct dst_entry *dst;
597
598 skb_list_del_init(skb);
599 /* if ingress device is enslaved to an L3 master device pass the
600 * skb to its handler for processing
601 */
602 skb = l3mdev_ip_rcv(skb);
603 if (!skb)
604 continue;
605 if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP)
606 continue;
607
608 dst = skb_dst(skb);
609 if (curr_dst != dst) {
610 hint = ip_extract_route_hint(net, skb,
611 ((struct rtable *)dst)->rt_type);
612
613 /* dispatch old sublist */
614 if (!list_empty(&sublist))
615 ip_sublist_rcv_finish(&sublist);
616 /* start new sublist */
617 INIT_LIST_HEAD(&sublist);
618 curr_dst = dst;
619 }
620 list_add_tail(&skb->list, &sublist);
621 }
622 /* dispatch final sublist */
623 ip_sublist_rcv_finish(&sublist);
624 }
625
ip_sublist_rcv(struct list_head * head,struct net_device * dev,struct net * net)626 static void ip_sublist_rcv(struct list_head *head, struct net_device *dev,
627 struct net *net)
628 {
629 NF_HOOK_LIST(NFPROTO_IPV4, NF_INET_PRE_ROUTING, net, NULL,
630 head, dev, NULL, ip_rcv_finish);
631 ip_list_rcv_finish(net, NULL, head);
632 }
633
634 /* Receive a list of IP packets */
ip_list_rcv(struct list_head * head,struct packet_type * pt,struct net_device * orig_dev)635 void ip_list_rcv(struct list_head *head, struct packet_type *pt,
636 struct net_device *orig_dev)
637 {
638 struct net_device *curr_dev = NULL;
639 struct net *curr_net = NULL;
640 struct sk_buff *skb, *next;
641 struct list_head sublist;
642
643 INIT_LIST_HEAD(&sublist);
644 list_for_each_entry_safe(skb, next, head, list) {
645 struct net_device *dev = skb->dev;
646 struct net *net = dev_net(dev);
647
648 skb_list_del_init(skb);
649 skb = ip_rcv_core(skb, net);
650 if (skb == NULL)
651 continue;
652
653 if (curr_dev != dev || curr_net != net) {
654 /* dispatch old sublist */
655 if (!list_empty(&sublist))
656 ip_sublist_rcv(&sublist, curr_dev, curr_net);
657 /* start new sublist */
658 INIT_LIST_HEAD(&sublist);
659 curr_dev = dev;
660 curr_net = net;
661 }
662 list_add_tail(&skb->list, &sublist);
663 }
664 /* dispatch final sublist */
665 if (!list_empty(&sublist))
666 ip_sublist_rcv(&sublist, curr_dev, curr_net);
667 }
668