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 | */ |
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(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 | |
185 | INDIRECT_CALLABLE_DECLARE(int udp_rcv(struct sk_buff *)); |
186 | INDIRECT_CALLABLE_DECLARE(int tcp_v4_rcv(struct sk_buff *)); |
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, 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 | |
227 | static int ip_local_deliver_finish(struct net *net, struct sock *sk, struct sk_buff *skb) |
228 | { |
229 | skb_clear_delivery_time(skb); |
230 | __skb_pull(skb, len: skb_network_header_len(skb)); |
231 | |
232 | rcu_read_lock(); |
233 | ip_protocol_deliver_rcu(net, skb, protocol: ip_hdr(skb)->protocol); |
234 | rcu_read_unlock(); |
235 | |
236 | return 0; |
237 | } |
238 | |
239 | /* |
240 | * Deliver IP Packets to the higher protocol layers. |
241 | */ |
242 | int ip_local_deliver(struct sk_buff *skb) |
243 | { |
244 | /* |
245 | * Reassemble IP fragments. |
246 | */ |
247 | struct net *net = dev_net(dev: skb->dev); |
248 | |
249 | if (ip_is_fragment(iph: ip_hdr(skb))) { |
250 | if (ip_defrag(net, skb, user: IP_DEFRAG_LOCAL_DELIVER)) |
251 | return 0; |
252 | } |
253 | |
254 | return NF_HOOK(pf: NFPROTO_IPV4, hook: NF_INET_LOCAL_IN, |
255 | net, NULL, skb, in: skb->dev, NULL, |
256 | okfn: ip_local_deliver_finish); |
257 | } |
258 | EXPORT_SYMBOL(ip_local_deliver); |
259 | |
260 | static inline bool ip_rcv_options(struct sk_buff *skb, struct net_device *dev) |
261 | { |
262 | struct ip_options *opt; |
263 | const struct iphdr *iph; |
264 | |
265 | /* It looks as overkill, because not all |
266 | IP options require packet mangling. |
267 | But it is the easiest for now, especially taking |
268 | into account that combination of IP options |
269 | and running sniffer is extremely rare condition. |
270 | --ANK (980813) |
271 | */ |
272 | if (skb_cow(skb, headroom: skb_headroom(skb))) { |
273 | __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INDISCARDS); |
274 | goto drop; |
275 | } |
276 | |
277 | iph = ip_hdr(skb); |
278 | opt = &(IPCB(skb)->opt); |
279 | opt->optlen = iph->ihl*4 - sizeof(struct iphdr); |
280 | |
281 | if (ip_options_compile(net: dev_net(dev), opt, skb)) { |
282 | __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INHDRERRORS); |
283 | goto drop; |
284 | } |
285 | |
286 | if (unlikely(opt->srr)) { |
287 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
288 | |
289 | if (in_dev) { |
290 | if (!IN_DEV_SOURCE_ROUTE(in_dev)) { |
291 | if (IN_DEV_LOG_MARTIANS(in_dev)) |
292 | net_info_ratelimited("source route option %pI4 -> %pI4\n" , |
293 | &iph->saddr, |
294 | &iph->daddr); |
295 | goto drop; |
296 | } |
297 | } |
298 | |
299 | if (ip_options_rcv_srr(skb, dev)) |
300 | goto drop; |
301 | } |
302 | |
303 | return false; |
304 | drop: |
305 | return true; |
306 | } |
307 | |
308 | static bool ip_can_use_hint(const struct sk_buff *skb, const struct iphdr *iph, |
309 | const struct sk_buff *hint) |
310 | { |
311 | return hint && !skb_dst(skb) && ip_hdr(skb: hint)->daddr == iph->daddr && |
312 | ip_hdr(skb: hint)->tos == iph->tos; |
313 | } |
314 | |
315 | int tcp_v4_early_demux(struct sk_buff *skb); |
316 | int udp_v4_early_demux(struct sk_buff *skb); |
317 | static int ip_rcv_finish_core(struct net *net, struct sock *sk, |
318 | struct sk_buff *skb, struct net_device *dev, |
319 | const struct sk_buff *hint) |
320 | { |
321 | const struct iphdr *iph = ip_hdr(skb); |
322 | int err, drop_reason; |
323 | struct rtable *rt; |
324 | |
325 | drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; |
326 | |
327 | if (ip_can_use_hint(skb, iph, hint)) { |
328 | err = ip_route_use_hint(skb, dst: iph->daddr, src: iph->saddr, tos: iph->tos, |
329 | devin: dev, hint); |
330 | if (unlikely(err)) |
331 | goto drop_error; |
332 | } |
333 | |
334 | if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) && |
335 | !skb_dst(skb) && |
336 | !skb->sk && |
337 | !ip_is_fragment(iph)) { |
338 | switch (iph->protocol) { |
339 | case IPPROTO_TCP: |
340 | if (READ_ONCE(net->ipv4.sysctl_tcp_early_demux)) { |
341 | tcp_v4_early_demux(skb); |
342 | |
343 | /* must reload iph, skb->head might have changed */ |
344 | iph = ip_hdr(skb); |
345 | } |
346 | break; |
347 | case IPPROTO_UDP: |
348 | if (READ_ONCE(net->ipv4.sysctl_udp_early_demux)) { |
349 | err = udp_v4_early_demux(skb); |
350 | if (unlikely(err)) |
351 | goto drop_error; |
352 | |
353 | /* must reload iph, skb->head might have changed */ |
354 | iph = ip_hdr(skb); |
355 | } |
356 | break; |
357 | } |
358 | } |
359 | |
360 | /* |
361 | * Initialise the virtual path cache for the packet. It describes |
362 | * how the packet travels inside Linux networking. |
363 | */ |
364 | if (!skb_valid_dst(skb)) { |
365 | err = ip_route_input_noref(skb, dst: iph->daddr, src: iph->saddr, |
366 | tos: iph->tos, devin: dev); |
367 | if (unlikely(err)) |
368 | goto drop_error; |
369 | } else { |
370 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
371 | |
372 | if (in_dev && IN_DEV_ORCONF(in_dev, NOPOLICY)) |
373 | IPCB(skb)->flags |= IPSKB_NOPOLICY; |
374 | } |
375 | |
376 | #ifdef CONFIG_IP_ROUTE_CLASSID |
377 | if (unlikely(skb_dst(skb)->tclassid)) { |
378 | struct ip_rt_acct *st = this_cpu_ptr(ip_rt_acct); |
379 | u32 idx = skb_dst(skb)->tclassid; |
380 | st[idx&0xFF].o_packets++; |
381 | st[idx&0xFF].o_bytes += skb->len; |
382 | st[(idx>>16)&0xFF].i_packets++; |
383 | st[(idx>>16)&0xFF].i_bytes += skb->len; |
384 | } |
385 | #endif |
386 | |
387 | if (iph->ihl > 5 && ip_rcv_options(skb, dev)) |
388 | goto drop; |
389 | |
390 | rt = skb_rtable(skb); |
391 | if (rt->rt_type == RTN_MULTICAST) { |
392 | __IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len); |
393 | } else if (rt->rt_type == RTN_BROADCAST) { |
394 | __IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len); |
395 | } else if (skb->pkt_type == PACKET_BROADCAST || |
396 | skb->pkt_type == PACKET_MULTICAST) { |
397 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
398 | |
399 | /* RFC 1122 3.3.6: |
400 | * |
401 | * When a host sends a datagram to a link-layer broadcast |
402 | * address, the IP destination address MUST be a legal IP |
403 | * broadcast or IP multicast address. |
404 | * |
405 | * A host SHOULD silently discard a datagram that is received |
406 | * via a link-layer broadcast (see Section 2.4) but does not |
407 | * specify an IP multicast or broadcast destination address. |
408 | * |
409 | * This doesn't explicitly say L2 *broadcast*, but broadcast is |
410 | * in a way a form of multicast and the most common use case for |
411 | * this is 802.11 protecting against cross-station spoofing (the |
412 | * so-called "hole-196" attack) so do it for both. |
413 | */ |
414 | if (in_dev && |
415 | IN_DEV_ORCONF(in_dev, DROP_UNICAST_IN_L2_MULTICAST)) { |
416 | drop_reason = SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST; |
417 | goto drop; |
418 | } |
419 | } |
420 | |
421 | return NET_RX_SUCCESS; |
422 | |
423 | drop: |
424 | kfree_skb_reason(skb, reason: drop_reason); |
425 | return NET_RX_DROP; |
426 | |
427 | drop_error: |
428 | if (err == -EXDEV) { |
429 | drop_reason = SKB_DROP_REASON_IP_RPFILTER; |
430 | __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER); |
431 | } |
432 | goto drop; |
433 | } |
434 | |
435 | static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) |
436 | { |
437 | struct net_device *dev = skb->dev; |
438 | int ret; |
439 | |
440 | /* if ingress device is enslaved to an L3 master device pass the |
441 | * skb to its handler for processing |
442 | */ |
443 | skb = l3mdev_ip_rcv(skb); |
444 | if (!skb) |
445 | return NET_RX_SUCCESS; |
446 | |
447 | ret = ip_rcv_finish_core(net, sk, skb, dev, NULL); |
448 | if (ret != NET_RX_DROP) |
449 | ret = dst_input(skb); |
450 | return ret; |
451 | } |
452 | |
453 | /* |
454 | * Main IP Receive routine. |
455 | */ |
456 | static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net) |
457 | { |
458 | const struct iphdr *iph; |
459 | int drop_reason; |
460 | u32 len; |
461 | |
462 | /* When the interface is in promisc. mode, drop all the crap |
463 | * that it receives, do not try to analyse it. |
464 | */ |
465 | if (skb->pkt_type == PACKET_OTHERHOST) { |
466 | dev_core_stats_rx_otherhost_dropped_inc(dev: skb->dev); |
467 | drop_reason = SKB_DROP_REASON_OTHERHOST; |
468 | goto drop; |
469 | } |
470 | |
471 | __IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len); |
472 | |
473 | skb = skb_share_check(skb, GFP_ATOMIC); |
474 | if (!skb) { |
475 | __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); |
476 | goto out; |
477 | } |
478 | |
479 | drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; |
480 | if (!pskb_may_pull(skb, len: sizeof(struct iphdr))) |
481 | goto inhdr_error; |
482 | |
483 | iph = ip_hdr(skb); |
484 | |
485 | /* |
486 | * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum. |
487 | * |
488 | * Is the datagram acceptable? |
489 | * |
490 | * 1. Length at least the size of an ip header |
491 | * 2. Version of 4 |
492 | * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums] |
493 | * 4. Doesn't have a bogus length |
494 | */ |
495 | |
496 | if (iph->ihl < 5 || iph->version != 4) |
497 | goto inhdr_error; |
498 | |
499 | BUILD_BUG_ON(IPSTATS_MIB_ECT1PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_1); |
500 | BUILD_BUG_ON(IPSTATS_MIB_ECT0PKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_ECT_0); |
501 | BUILD_BUG_ON(IPSTATS_MIB_CEPKTS != IPSTATS_MIB_NOECTPKTS + INET_ECN_CE); |
502 | __IP_ADD_STATS(net, |
503 | IPSTATS_MIB_NOECTPKTS + (iph->tos & INET_ECN_MASK), |
504 | max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs)); |
505 | |
506 | if (!pskb_may_pull(skb, len: iph->ihl*4)) |
507 | goto inhdr_error; |
508 | |
509 | iph = ip_hdr(skb); |
510 | |
511 | if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) |
512 | goto csum_error; |
513 | |
514 | len = iph_totlen(skb, iph); |
515 | if (skb->len < len) { |
516 | drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; |
517 | __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS); |
518 | goto drop; |
519 | } else if (len < (iph->ihl*4)) |
520 | goto inhdr_error; |
521 | |
522 | /* Our transport medium may have padded the buffer out. Now we know it |
523 | * is IP we can trim to the true length of the frame. |
524 | * Note this now means skb->len holds ntohs(iph->tot_len). |
525 | */ |
526 | if (pskb_trim_rcsum(skb, len)) { |
527 | __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); |
528 | goto drop; |
529 | } |
530 | |
531 | iph = ip_hdr(skb); |
532 | skb->transport_header = skb->network_header + iph->ihl*4; |
533 | |
534 | /* Remove any debris in the socket control block */ |
535 | memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); |
536 | IPCB(skb)->iif = skb->skb_iif; |
537 | |
538 | /* Must drop socket now because of tproxy. */ |
539 | if (!skb_sk_is_prefetched(skb)) |
540 | skb_orphan(skb); |
541 | |
542 | return skb; |
543 | |
544 | csum_error: |
545 | drop_reason = SKB_DROP_REASON_IP_CSUM; |
546 | __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS); |
547 | inhdr_error: |
548 | if (drop_reason == SKB_DROP_REASON_NOT_SPECIFIED) |
549 | drop_reason = SKB_DROP_REASON_IP_INHDR; |
550 | __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS); |
551 | drop: |
552 | kfree_skb_reason(skb, reason: drop_reason); |
553 | out: |
554 | return NULL; |
555 | } |
556 | |
557 | /* |
558 | * IP receive entry point |
559 | */ |
560 | int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, |
561 | struct net_device *orig_dev) |
562 | { |
563 | struct net *net = dev_net(dev); |
564 | |
565 | skb = ip_rcv_core(skb, net); |
566 | if (skb == NULL) |
567 | return NET_RX_DROP; |
568 | |
569 | return NF_HOOK(pf: NFPROTO_IPV4, hook: NF_INET_PRE_ROUTING, |
570 | net, NULL, skb, in: dev, NULL, |
571 | okfn: ip_rcv_finish); |
572 | } |
573 | |
574 | static void ip_sublist_rcv_finish(struct list_head *head) |
575 | { |
576 | struct sk_buff *skb, *next; |
577 | |
578 | list_for_each_entry_safe(skb, next, head, list) { |
579 | skb_list_del_init(skb); |
580 | dst_input(skb); |
581 | } |
582 | } |
583 | |
584 | static struct sk_buff *(const struct net *net, |
585 | struct sk_buff *skb, int rt_type) |
586 | { |
587 | if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST || |
588 | IPCB(skb)->flags & IPSKB_MULTIPATH) |
589 | return NULL; |
590 | |
591 | return skb; |
592 | } |
593 | |
594 | static void ip_list_rcv_finish(struct net *net, struct sock *sk, |
595 | struct list_head *head) |
596 | { |
597 | struct sk_buff *skb, *next, *hint = NULL; |
598 | struct dst_entry *curr_dst = NULL; |
599 | struct list_head sublist; |
600 | |
601 | INIT_LIST_HEAD(list: &sublist); |
602 | list_for_each_entry_safe(skb, next, head, list) { |
603 | struct net_device *dev = skb->dev; |
604 | struct dst_entry *dst; |
605 | |
606 | skb_list_del_init(skb); |
607 | /* if ingress device is enslaved to an L3 master device pass the |
608 | * skb to its handler for processing |
609 | */ |
610 | skb = l3mdev_ip_rcv(skb); |
611 | if (!skb) |
612 | continue; |
613 | if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP) |
614 | continue; |
615 | |
616 | dst = skb_dst(skb); |
617 | if (curr_dst != dst) { |
618 | hint = ip_extract_route_hint(net, skb, |
619 | rt_type: ((struct rtable *)dst)->rt_type); |
620 | |
621 | /* dispatch old sublist */ |
622 | if (!list_empty(head: &sublist)) |
623 | ip_sublist_rcv_finish(head: &sublist); |
624 | /* start new sublist */ |
625 | INIT_LIST_HEAD(list: &sublist); |
626 | curr_dst = dst; |
627 | } |
628 | list_add_tail(new: &skb->list, head: &sublist); |
629 | } |
630 | /* dispatch final sublist */ |
631 | ip_sublist_rcv_finish(head: &sublist); |
632 | } |
633 | |
634 | static void ip_sublist_rcv(struct list_head *head, struct net_device *dev, |
635 | struct net *net) |
636 | { |
637 | NF_HOOK_LIST(pf: NFPROTO_IPV4, hook: NF_INET_PRE_ROUTING, net, NULL, |
638 | head, in: dev, NULL, okfn: ip_rcv_finish); |
639 | ip_list_rcv_finish(net, NULL, head); |
640 | } |
641 | |
642 | /* Receive a list of IP packets */ |
643 | void ip_list_rcv(struct list_head *head, struct packet_type *pt, |
644 | struct net_device *orig_dev) |
645 | { |
646 | struct net_device *curr_dev = NULL; |
647 | struct net *curr_net = NULL; |
648 | struct sk_buff *skb, *next; |
649 | struct list_head sublist; |
650 | |
651 | INIT_LIST_HEAD(list: &sublist); |
652 | list_for_each_entry_safe(skb, next, head, list) { |
653 | struct net_device *dev = skb->dev; |
654 | struct net *net = dev_net(dev); |
655 | |
656 | skb_list_del_init(skb); |
657 | skb = ip_rcv_core(skb, net); |
658 | if (skb == NULL) |
659 | continue; |
660 | |
661 | if (curr_dev != dev || curr_net != net) { |
662 | /* dispatch old sublist */ |
663 | if (!list_empty(head: &sublist)) |
664 | ip_sublist_rcv(head: &sublist, dev: curr_dev, net: curr_net); |
665 | /* start new sublist */ |
666 | INIT_LIST_HEAD(list: &sublist); |
667 | curr_dev = dev; |
668 | curr_net = net; |
669 | } |
670 | list_add_tail(new: &skb->list, head: &sublist); |
671 | } |
672 | /* dispatch final sublist */ |
673 | if (!list_empty(head: &sublist)) |
674 | ip_sublist_rcv(head: &sublist, dev: curr_dev, net: curr_net); |
675 | } |
676 | |