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 */
148bool 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(iph: ip_hdr(skb))) {
166 if (ip_defrag(net, skb, user: 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
185INDIRECT_CALLABLE_DECLARE(int udp_rcv(struct sk_buff *));
186INDIRECT_CALLABLE_DECLARE(int tcp_v4_rcv(struct sk_buff *));
187void 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
192resubmit:
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, dir: XFRM_POLICY_IN, skb)) {
199 kfree_skb_reason(skb,
200 reason: 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, dir: XFRM_POLICY_IN, skb)) {
215 __IP_INC_STATS(net, IPSTATS_MIB_INUNKNOWNPROTOS);
216 icmp_send(skb_in: skb, ICMP_DEST_UNREACH,
217 ICMP_PROT_UNREACH, info: 0);
218 }
219 kfree_skb_reason(skb, reason: SKB_DROP_REASON_IP_NOPROTO);
220 } else {
221 __IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS);
222 consume_skb(skb);
223 }
224 }
225}
226
227static int ip_local_deliver_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
228{
229 if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
230 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
231 kfree_skb_reason(skb, reason: SKB_DROP_REASON_NOMEM);
232 return 0;
233 }
234
235 skb_clear_delivery_time(skb);
236 __skb_pull(skb, len: skb_network_header_len(skb));
237
238 rcu_read_lock();
239 ip_protocol_deliver_rcu(net, skb, protocol: ip_hdr(skb)->protocol);
240 rcu_read_unlock();
241
242 return 0;
243}
244
245/*
246 * Deliver IP Packets to the higher protocol layers.
247 */
248int ip_local_deliver(struct sk_buff *skb)
249{
250 /*
251 * Reassemble IP fragments.
252 */
253 struct net *net = dev_net(dev: skb->dev);
254
255 if (ip_is_fragment(iph: ip_hdr(skb))) {
256 if (ip_defrag(net, skb, user: IP_DEFRAG_LOCAL_DELIVER))
257 return 0;
258 }
259
260 return NF_HOOK(pf: NFPROTO_IPV4, hook: NF_INET_LOCAL_IN,
261 net, NULL, skb, in: skb->dev, NULL,
262 okfn: ip_local_deliver_finish);
263}
264EXPORT_SYMBOL(ip_local_deliver);
265
266static inline enum skb_drop_reason
267ip_rcv_options(struct sk_buff *skb, struct net_device *dev)
268{
269 const struct iphdr *iph;
270 struct ip_options *opt;
271
272 /* It looks as overkill, because not all
273 IP options require packet mangling.
274 But it is the easiest for now, especially taking
275 into account that combination of IP options
276 and running sniffer is extremely rare condition.
277 --ANK (980813)
278 */
279 if (skb_cow(skb, headroom: skb_headroom(skb))) {
280 __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INDISCARDS);
281 return SKB_DROP_REASON_NOMEM;
282 }
283
284 iph = ip_hdr(skb);
285 opt = &(IPCB(skb)->opt);
286 opt->optlen = iph->ihl*4 - sizeof(struct iphdr);
287
288 if (ip_options_compile(net: dev_net(dev), opt, skb)) {
289 __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INHDRERRORS);
290 return SKB_DROP_REASON_IP_INHDR;
291 }
292
293 if (unlikely(opt->srr)) {
294 struct in_device *in_dev = __in_dev_get_rcu(dev);
295
296 if (in_dev) {
297 if (!IN_DEV_SOURCE_ROUTE(in_dev)) {
298 if (IN_DEV_LOG_MARTIANS(in_dev))
299 net_info_ratelimited("source route option %pI4 -> %pI4\n",
300 &iph->saddr,
301 &iph->daddr);
302 return SKB_DROP_REASON_NOT_SPECIFIED;
303 }
304 }
305
306 if (ip_options_rcv_srr(skb, dev))
307 return SKB_DROP_REASON_NOT_SPECIFIED;
308 }
309
310 return SKB_NOT_DROPPED_YET;
311}
312
313static bool ip_can_use_hint(const struct sk_buff *skb, const struct iphdr *iph,
314 const struct sk_buff *hint)
315{
316 return hint && !skb_dst(skb) && ip_hdr(skb: hint)->daddr == iph->daddr &&
317 ip_hdr(skb: hint)->tos == iph->tos;
318}
319
320int tcp_v4_early_demux(struct sk_buff *skb);
321enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb);
322static int ip_rcv_finish_core(struct net *net,
323 struct sk_buff *skb, struct net_device *dev,
324 const struct sk_buff *hint)
325{
326 const struct iphdr *iph = ip_hdr(skb);
327 struct rtable *rt;
328 int drop_reason;
329
330 if (ip_can_use_hint(skb, iph, hint)) {
331 drop_reason = ip_route_use_hint(skb, daddr: iph->daddr, saddr: iph->saddr,
332 dscp: ip4h_dscp(ip4h: iph), dev, hint);
333 if (unlikely(drop_reason))
334 goto drop_error;
335 }
336
337 if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) &&
338 !skb_dst(skb) &&
339 !skb->sk &&
340 !ip_is_fragment(iph)) {
341 switch (iph->protocol) {
342 case IPPROTO_TCP:
343 if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) {
344 tcp_v4_early_demux(skb);
345
346 /* must reload iph, skb->head might have changed */
347 iph = ip_hdr(skb);
348 }
349 break;
350 case IPPROTO_UDP:
351 if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) {
352 drop_reason = udp_v4_early_demux(skb);
353 if (unlikely(drop_reason))
354 goto drop_error;
355
356 /* must reload iph, skb->head might have changed */
357 iph = ip_hdr(skb);
358 }
359 break;
360 }
361 }
362
363 /*
364 * Initialise the virtual path cache for the packet. It describes
365 * how the packet travels inside Linux networking.
366 */
367 if (!skb_valid_dst(skb)) {
368 drop_reason = ip_route_input_noref(skb, daddr: iph->daddr, saddr: iph->saddr,
369 dscp: ip4h_dscp(ip4h: iph), dev);
370 if (unlikely(drop_reason))
371 goto drop_error;
372 } else {
373 struct in_device *in_dev = __in_dev_get_rcu(dev);
374
375 if (in_dev && IN_DEV_ORCONF(in_dev, NOPOLICY))
376 IPCB(skb)->flags |= IPSKB_NOPOLICY;
377 }
378
379#ifdef CONFIG_IP_ROUTE_CLASSID
380 if (unlikely(skb_dst(skb)->tclassid)) {
381 struct ip_rt_acct *st = this_cpu_ptr(ip_rt_acct);
382 u32 idx = skb_dst(skb)->tclassid;
383 st[idx&0xFF].o_packets++;
384 st[idx&0xFF].o_bytes += skb->len;
385 st[(idx>>16)&0xFF].i_packets++;
386 st[(idx>>16)&0xFF].i_bytes += skb->len;
387 }
388#endif
389
390 if (iph->ihl > 5) {
391 drop_reason = ip_rcv_options(skb, dev);
392 if (drop_reason)
393 goto drop;
394 }
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 drop_reason = SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST;
423 goto drop;
424 }
425 }
426
427 return NET_RX_SUCCESS;
428
429drop:
430 kfree_skb_reason(skb, reason: drop_reason);
431 return NET_RX_DROP;
432
433drop_error:
434 if (drop_reason == SKB_DROP_REASON_IP_RPFILTER)
435 __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER);
436 goto drop;
437}
438
439static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
440{
441 struct net_device *dev = skb->dev;
442 int ret;
443
444 /* if ingress device is enslaved to an L3 master device pass the
445 * skb to its handler for processing
446 */
447 skb = l3mdev_ip_rcv(skb);
448 if (!skb)
449 return NET_RX_SUCCESS;
450
451 ret = ip_rcv_finish_core(net, skb, dev, NULL);
452 if (ret != NET_RX_DROP)
453 ret = dst_input(skb);
454 return ret;
455}
456
457/*
458 * Main IP Receive routine.
459 */
460static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
461{
462 const struct iphdr *iph;
463 int drop_reason;
464 u32 len;
465
466 /* When the interface is in promisc. mode, drop all the crap
467 * that it receives, do not try to analyse it.
468 */
469 if (skb->pkt_type == PACKET_OTHERHOST) {
470 dev_core_stats_rx_otherhost_dropped_inc(dev: skb->dev);
471 drop_reason = SKB_DROP_REASON_OTHERHOST;
472 goto drop;
473 }
474
475 __IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len);
476
477 skb = skb_share_check(skb, GFP_ATOMIC);
478 if (!skb) {
479 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
480 goto out;
481 }
482
483 drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
484 if (!pskb_may_pull(skb, len: sizeof(struct iphdr)))
485 goto inhdr_error;
486
487 iph = ip_hdr(skb);
488
489 /*
490 * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum.
491 *
492 * Is the datagram acceptable?
493 *
494 * 1. Length at least the size of an ip header
495 * 2. Version of 4
496 * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums]
497 * 4. Doesn't have a bogus length
498 */
499
500 if (iph->ihl < 5 || iph->version != 4)
501 goto inhdr_error;
502
503 BUILD_BUG_ON(IPSTATS_MIB_ECT1PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_1);
504 BUILD_BUG_ON(IPSTATS_MIB_ECT0PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_0);
505 BUILD_BUG_ON(IPSTATS_MIB_CEPKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_CE);
506 __IP_ADD_STATS(net,
507 IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK),
508 max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));
509
510 if (!pskb_may_pull(skb, len: iph->ihl*4))
511 goto inhdr_error;
512
513 iph = ip_hdr(skb);
514
515 if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
516 goto csum_error;
517
518 len = iph_totlen(skb, iph);
519 if (skb->len < len) {
520 drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
521 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
522 goto drop;
523 } else if (len < (iph->ihl*4))
524 goto inhdr_error;
525
526 /* Our transport medium may have padded the buffer out. Now we know it
527 * is IP we can trim to the true length of the frame.
528 * Note this now means skb->len holds ntohs(iph->tot_len).
529 */
530 if (pskb_trim_rcsum(skb, len)) {
531 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
532 goto drop;
533 }
534
535 iph = ip_hdr(skb);
536 skb->transport_header = skb->network_header + iph->ihl*4;
537
538 /* Remove any debris in the socket control block */
539 memset(IPCB(skb), c: 0, n: sizeof(struct inet_skb_parm));
540 IPCB(skb)->iif = skb->skb_iif;
541
542 /* Must drop socket now because of tproxy. */
543 if (!skb_sk_is_prefetched(skb))
544 skb_orphan(skb);
545
546 return skb;
547
548csum_error:
549 drop_reason = SKB_DROP_REASON_IP_CSUM;
550 __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
551inhdr_error:
552 if (drop_reason == SKB_DROP_REASON_NOT_SPECIFIED)
553 drop_reason = SKB_DROP_REASON_IP_INHDR;
554 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
555drop:
556 kfree_skb_reason(skb, reason: drop_reason);
557out:
558 return NULL;
559}
560
561/*
562 * IP receive entry point
563 */
564int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
565 struct net_device *orig_dev)
566{
567 struct net *net = dev_net(dev);
568
569 skb = ip_rcv_core(skb, net);
570 if (skb == NULL)
571 return NET_RX_DROP;
572
573 return NF_HOOK(pf: NFPROTO_IPV4, hook: NF_INET_PRE_ROUTING,
574 net, NULL, skb, in: dev, NULL,
575 okfn: ip_rcv_finish);
576}
577
578static void ip_sublist_rcv_finish(struct list_head *head)
579{
580 struct sk_buff *skb, *next;
581
582 list_for_each_entry_safe(skb, next, head, list) {
583 skb_list_del_init(skb);
584 dst_input(skb);
585 }
586}
587
588static struct sk_buff *ip_extract_route_hint(const struct net *net,
589 struct sk_buff *skb)
590{
591 const struct iphdr *iph = ip_hdr(skb);
592
593 if (fib4_has_custom_rules(net) ||
594 ipv4_is_lbcast(addr: iph->daddr) ||
595 ipv4_is_zeronet(addr: iph->daddr) ||
596 IPCB(skb)->flags & IPSKB_MULTIPATH)
597 return NULL;
598
599 return skb;
600}
601
602static void ip_list_rcv_finish(struct net *net, struct list_head *head)
603{
604 struct sk_buff *skb, *next, *hint = NULL;
605 struct dst_entry *curr_dst = NULL;
606 LIST_HEAD(sublist);
607
608 list_for_each_entry_safe(skb, next, head, list) {
609 struct net_device *dev = skb->dev;
610 struct dst_entry *dst;
611
612 skb_list_del_init(skb);
613 /* if ingress device is enslaved to an L3 master device pass the
614 * skb to its handler for processing
615 */
616 skb = l3mdev_ip_rcv(skb);
617 if (!skb)
618 continue;
619 if (ip_rcv_finish_core(net, skb, dev, hint) == NET_RX_DROP)
620 continue;
621
622 dst = skb_dst(skb);
623 if (curr_dst != dst) {
624 hint = ip_extract_route_hint(net, skb);
625
626 /* dispatch old sublist */
627 if (!list_empty(head: &sublist))
628 ip_sublist_rcv_finish(head: &sublist);
629 /* start new sublist */
630 INIT_LIST_HEAD(list: &sublist);
631 curr_dst = dst;
632 }
633 list_add_tail(new: &skb->list, head: &sublist);
634 }
635 /* dispatch final sublist */
636 ip_sublist_rcv_finish(head: &sublist);
637}
638
639static void ip_sublist_rcv(struct list_head *head, struct net_device *dev,
640 struct net *net)
641{
642 NF_HOOK_LIST(pf: NFPROTO_IPV4, hook: NF_INET_PRE_ROUTING, net, NULL,
643 head, in: dev, NULL, okfn: ip_rcv_finish);
644 ip_list_rcv_finish(net, head);
645}
646
647/* Receive a list of IP packets */
648void ip_list_rcv(struct list_head *head, struct packet_type *pt,
649 struct net_device *orig_dev)
650{
651 struct net_device *curr_dev = NULL;
652 struct net *curr_net = NULL;
653 struct sk_buff *skb, *next;
654 LIST_HEAD(sublist);
655
656 list_for_each_entry_safe(skb, next, head, list) {
657 struct net_device *dev = skb->dev;
658 struct net *net = dev_net(dev);
659
660 skb_list_del_init(skb);
661 skb = ip_rcv_core(skb, net);
662 if (skb == NULL)
663 continue;
664
665 if (curr_dev != dev || curr_net != net) {
666 /* dispatch old sublist */
667 if (!list_empty(head: &sublist))
668 ip_sublist_rcv(head: &sublist, dev: curr_dev, net: curr_net);
669 /* start new sublist */
670 INIT_LIST_HEAD(list: &sublist);
671 curr_dev = dev;
672 curr_net = net;
673 }
674 list_add_tail(new: &skb->list, head: &sublist);
675 }
676 /* dispatch final sublist */
677 if (!list_empty(head: &sublist))
678 ip_sublist_rcv(head: &sublist, dev: curr_dev, net: curr_net);
679}
680