Commit | Line | Data |
---|---|---|
2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
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 | * | |
02c30a84 | 9 | * Authors: Ross Biro |
1da177e4 LT |
10 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
11 | * Donald Becker, <becker@super.org> | |
113aa838 | 12 | * Alan Cox, <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
13 | * Richard Underwood |
14 | * Stefan Becker, <stefanb@yello.ping.de> | |
15 | * Jorge Cwik, <jorge@laser.satlink.net> | |
16 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> | |
e905a9ed | 17 | * |
1da177e4 LT |
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 | * | |
1da177e4 LT |
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. | |
e905a9ed | 103 | * Output fragmentation wants updating along with the buffer management to use a single |
1da177e4 LT |
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. | |
1da177e4 LT |
107 | */ |
108 | ||
afd46503 JP |
109 | #define pr_fmt(fmt) "IPv4: " fmt |
110 | ||
1da177e4 LT |
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> | |
5a0e3ad6 | 116 | #include <linux/slab.h> |
1da177e4 LT |
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> | |
14c85021 | 123 | #include <linux/inetdevice.h> |
1da177e4 LT |
124 | #include <linux/netdevice.h> |
125 | #include <linux/etherdevice.h> | |
0e219ae4 | 126 | #include <linux/indirect_call_wrapper.h> |
1da177e4 LT |
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> | |
1f07d03e | 138 | #include <net/inet_ecn.h> |
1da177e4 LT |
139 | #include <linux/netfilter_ipv4.h> |
140 | #include <net/xfrm.h> | |
141 | #include <linux/mroute.h> | |
142 | #include <linux/netlink.h> | |
f38a9eb1 | 143 | #include <net/dst_metadata.h> |
1da177e4 | 144 | |
1da177e4 | 145 | /* |
66018506 | 146 | * Process Router Attention IP option (RFC 2113) |
e905a9ed | 147 | */ |
ba57b4db | 148 | bool ip_call_ra_chain(struct sk_buff *skb) |
1da177e4 LT |
149 | { |
150 | struct ip_ra_chain *ra; | |
eddc9ec5 | 151 | u8 protocol = ip_hdr(skb)->protocol; |
1da177e4 | 152 | struct sock *last = NULL; |
cb84663e | 153 | struct net_device *dev = skb->dev; |
37fcbab6 | 154 | struct net *net = dev_net(dev); |
1da177e4 | 155 | |
5796ef75 | 156 | for (ra = rcu_dereference(net->ipv4.ra_chain); ra; ra = rcu_dereference(ra->next)) { |
1da177e4 LT |
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 | */ | |
c720c7e8 | 162 | if (sk && inet_sk(sk)->inet_num == protocol && |
1da177e4 | 163 | (!sk->sk_bound_dev_if || |
5796ef75 | 164 | sk->sk_bound_dev_if == dev->ifindex)) { |
56f8a75c | 165 | if (ip_is_fragment(ip_hdr(skb))) { |
19bcf9f2 | 166 | if (ip_defrag(net, skb, IP_DEFRAG_CALL_RA_CHAIN)) |
ba57b4db | 167 | return true; |
1da177e4 LT |
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); | |
ba57b4db | 180 | return true; |
1da177e4 | 181 | } |
ba57b4db | 182 | return false; |
1da177e4 LT |
183 | } |
184 | ||
0e219ae4 PA |
185 | INDIRECT_CALLABLE_DECLARE(int udp_rcv(struct sk_buff *)); |
186 | INDIRECT_CALLABLE_DECLARE(int tcp_v4_rcv(struct sk_buff *)); | |
68cb7d53 | 187 | void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int protocol) |
1da177e4 | 188 | { |
68cb7d53 PA |
189 | const struct net_protocol *ipprot; |
190 | int raw, ret; | |
1da177e4 | 191 | |
68cb7d53 PA |
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)) { | |
10580c47 MD |
199 | kfree_skb_reason(skb, |
200 | SKB_DROP_REASON_XFRM_POLICY); | |
68cb7d53 | 201 | return; |
1da177e4 | 202 | } |
895b5c9f | 203 | nf_reset_ct(skb); |
68cb7d53 | 204 | } |
0e219ae4 PA |
205 | ret = INDIRECT_CALL_2(ipprot->handler, tcp_v4_rcv, udp_rcv, |
206 | skb); | |
68cb7d53 PA |
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, XFRM_POLICY_IN, skb)) { | |
215 | __IP_INC_STATS(net, IPSTATS_MIB_INUNKNOWNPROTOS); | |
216 | icmp_send(skb, ICMP_DEST_UNREACH, | |
217 | ICMP_PROT_UNREACH, 0); | |
1da177e4 | 218 | } |
10580c47 | 219 | kfree_skb_reason(skb, SKB_DROP_REASON_IP_NOPROTO); |
1da177e4 | 220 | } else { |
68cb7d53 PA |
221 | __IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS); |
222 | consume_skb(skb); | |
1da177e4 LT |
223 | } |
224 | } | |
68cb7d53 PA |
225 | } |
226 | ||
227 | static int ip_local_deliver_finish(struct net *net, struct sock *sk, struct sk_buff *skb) | |
228 | { | |
cd14e9b7 | 229 | skb_clear_delivery_time(skb); |
68cb7d53 PA |
230 | __skb_pull(skb, skb_network_header_len(skb)); |
231 | ||
232 | rcu_read_lock(); | |
233 | ip_protocol_deliver_rcu(net, skb, ip_hdr(skb)->protocol); | |
1da177e4 LT |
234 | rcu_read_unlock(); |
235 | ||
236 | return 0; | |
237 | } | |
238 | ||
239 | /* | |
240 | * Deliver IP Packets to the higher protocol layers. | |
e905a9ed | 241 | */ |
1da177e4 LT |
242 | int ip_local_deliver(struct sk_buff *skb) |
243 | { | |
244 | /* | |
245 | * Reassemble IP fragments. | |
246 | */ | |
19bcf9f2 | 247 | struct net *net = dev_net(skb->dev); |
1da177e4 | 248 | |
56f8a75c | 249 | if (ip_is_fragment(ip_hdr(skb))) { |
19bcf9f2 | 250 | if (ip_defrag(net, skb, IP_DEFRAG_LOCAL_DELIVER)) |
1da177e4 LT |
251 | return 0; |
252 | } | |
253 | ||
29a26a56 | 254 | return NF_HOOK(NFPROTO_IPV4, NF_INET_LOCAL_IN, |
19bcf9f2 | 255 | net, NULL, skb, skb->dev, NULL, |
1da177e4 LT |
256 | ip_local_deliver_finish); |
257 | } | |
e43b2190 | 258 | EXPORT_SYMBOL(ip_local_deliver); |
1da177e4 | 259 | |
8c83f2df | 260 | static inline bool ip_rcv_options(struct sk_buff *skb, struct net_device *dev) |
d245407e TG |
261 | { |
262 | struct ip_options *opt; | |
b71d1d42 | 263 | const struct iphdr *iph; |
d245407e TG |
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, skb_headroom(skb))) { | |
b45386ef | 273 | __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INDISCARDS); |
d245407e TG |
274 | goto drop; |
275 | } | |
276 | ||
eddc9ec5 | 277 | iph = ip_hdr(skb); |
22aba383 DL |
278 | opt = &(IPCB(skb)->opt); |
279 | opt->optlen = iph->ihl*4 - sizeof(struct iphdr); | |
d245407e | 280 | |
c346dca1 | 281 | if (ip_options_compile(dev_net(dev), opt, skb)) { |
b45386ef | 282 | __IP_INC_STATS(dev_net(dev), IPSTATS_MIB_INHDRERRORS); |
d245407e TG |
283 | goto drop; |
284 | } | |
285 | ||
d245407e | 286 | if (unlikely(opt->srr)) { |
6e8b11b4 ED |
287 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
288 | ||
d245407e TG |
289 | if (in_dev) { |
290 | if (!IN_DEV_SOURCE_ROUTE(in_dev)) { | |
e87cc472 JP |
291 | if (IN_DEV_LOG_MARTIANS(in_dev)) |
292 | net_info_ratelimited("source route option %pI4 -> %pI4\n", | |
293 | &iph->saddr, | |
294 | &iph->daddr); | |
d245407e TG |
295 | goto drop; |
296 | } | |
d245407e TG |
297 | } |
298 | ||
8c83f2df | 299 | if (ip_options_rcv_srr(skb, dev)) |
d245407e TG |
300 | goto drop; |
301 | } | |
302 | ||
6a91395f | 303 | return false; |
d245407e | 304 | drop: |
6a91395f | 305 | return true; |
d245407e TG |
306 | } |
307 | ||
02b24941 PA |
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(hint)->daddr == iph->daddr && | |
312 | ip_hdr(hint)->tos == iph->tos; | |
313 | } | |
314 | ||
11052589 KI |
315 | int tcp_v4_early_demux(struct sk_buff *skb); |
316 | int udp_v4_early_demux(struct sk_buff *skb); | |
5fa12739 | 317 | static int ip_rcv_finish_core(struct net *net, struct sock *sk, |
02b24941 PA |
318 | struct sk_buff *skb, struct net_device *dev, |
319 | const struct sk_buff *hint) | |
1da177e4 | 320 | { |
eddc9ec5 | 321 | const struct iphdr *iph = ip_hdr(skb); |
c1f166d1 | 322 | int err, drop_reason; |
7487449c | 323 | struct rtable *rt; |
c1f166d1 MD |
324 | |
325 | drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; | |
1da177e4 | 326 | |
02b24941 PA |
327 | if (ip_can_use_hint(skb, iph, hint)) { |
328 | err = ip_route_use_hint(skb, iph->daddr, iph->saddr, iph->tos, | |
329 | dev, hint); | |
330 | if (unlikely(err)) | |
331 | goto drop_error; | |
332 | } | |
333 | ||
11052589 | 334 | if (READ_ONCE(net->ipv4.sysctl_ip_early_demux) && |
63e51b6a ED |
335 | !skb_dst(skb) && |
336 | !skb->sk && | |
337 | !ip_is_fragment(iph)) { | |
11052589 KI |
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; | |
9cb429d6 | 357 | } |
160eb5a6 DM |
358 | } |
359 | ||
1da177e4 LT |
360 | /* |
361 | * Initialise the virtual path cache for the packet. It describes | |
362 | * how the packet travels inside Linux networking. | |
e905a9ed | 363 | */ |
f38a9eb1 | 364 | if (!skb_valid_dst(skb)) { |
7487449c PA |
365 | err = ip_route_input_noref(skb, iph->daddr, iph->saddr, |
366 | iph->tos, dev); | |
367 | if (unlikely(err)) | |
368 | goto drop_error; | |
3a591318 EB |
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; | |
1da177e4 LT |
374 | } |
375 | ||
c7066f70 | 376 | #ifdef CONFIG_IP_ROUTE_CLASSID |
adf30907 | 377 | if (unlikely(skb_dst(skb)->tclassid)) { |
7a9b2d59 | 378 | struct ip_rt_acct *st = this_cpu_ptr(ip_rt_acct); |
adf30907 | 379 | u32 idx = skb_dst(skb)->tclassid; |
1da177e4 | 380 | st[idx&0xFF].o_packets++; |
fd3f8c4c | 381 | st[idx&0xFF].o_bytes += skb->len; |
1da177e4 | 382 | st[(idx>>16)&0xFF].i_packets++; |
fd3f8c4c | 383 | st[(idx>>16)&0xFF].i_bytes += skb->len; |
1da177e4 LT |
384 | } |
385 | #endif | |
386 | ||
8c83f2df | 387 | if (iph->ihl > 5 && ip_rcv_options(skb, dev)) |
d245407e | 388 | goto drop; |
1da177e4 | 389 | |
511c3f92 | 390 | rt = skb_rtable(skb); |
edf391ff | 391 | if (rt->rt_type == RTN_MULTICAST) { |
b15084ec | 392 | __IP_UPD_PO_STATS(net, IPSTATS_MIB_INMCAST, skb->len); |
12b74dfa | 393 | } else if (rt->rt_type == RTN_BROADCAST) { |
b15084ec | 394 | __IP_UPD_PO_STATS(net, IPSTATS_MIB_INBCAST, skb->len); |
12b74dfa JB |
395 | } else if (skb->pkt_type == PACKET_BROADCAST || |
396 | skb->pkt_type == PACKET_MULTICAST) { | |
d6f64d72 | 397 | struct in_device *in_dev = __in_dev_get_rcu(dev); |
12b74dfa JB |
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 && | |
c1f166d1 MD |
415 | IN_DEV_ORCONF(in_dev, DROP_UNICAST_IN_L2_MULTICAST)) { |
416 | drop_reason = SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST; | |
12b74dfa | 417 | goto drop; |
c1f166d1 | 418 | } |
12b74dfa | 419 | } |
5506b54b | 420 | |
5fa12739 | 421 | return NET_RX_SUCCESS; |
1da177e4 | 422 | |
1da177e4 | 423 | drop: |
c1f166d1 | 424 | kfree_skb_reason(skb, drop_reason); |
e905a9ed | 425 | return NET_RX_DROP; |
7487449c PA |
426 | |
427 | drop_error: | |
c1f166d1 MD |
428 | if (err == -EXDEV) { |
429 | drop_reason = SKB_DROP_REASON_IP_RPFILTER; | |
7487449c | 430 | __NET_INC_STATS(net, LINUX_MIB_IPRPFILTER); |
c1f166d1 | 431 | } |
7487449c | 432 | goto drop; |
1da177e4 LT |
433 | } |
434 | ||
5fa12739 EC |
435 | static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb) |
436 | { | |
a1fd1ad2 | 437 | struct net_device *dev = skb->dev; |
efe6aaca EC |
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; | |
5fa12739 | 446 | |
02b24941 | 447 | ret = ip_rcv_finish_core(net, sk, skb, dev, NULL); |
5fa12739 EC |
448 | if (ret != NET_RX_DROP) |
449 | ret = dst_input(skb); | |
450 | return ret; | |
451 | } | |
452 | ||
1da177e4 LT |
453 | /* |
454 | * Main IP Receive routine. | |
e905a9ed | 455 | */ |
17266ee9 | 456 | static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net) |
1da177e4 | 457 | { |
b71d1d42 | 458 | const struct iphdr *iph; |
33cba429 | 459 | int drop_reason; |
58615242 | 460 | u32 len; |
1da177e4 LT |
461 | |
462 | /* When the interface is in promisc. mode, drop all the crap | |
463 | * that it receives, do not try to analyse it. | |
464 | */ | |
33cba429 | 465 | if (skb->pkt_type == PACKET_OTHERHOST) { |
794c24e9 | 466 | dev_core_stats_rx_otherhost_dropped_inc(skb->dev); |
33cba429 | 467 | drop_reason = SKB_DROP_REASON_OTHERHOST; |
1da177e4 | 468 | goto drop; |
33cba429 | 469 | } |
1da177e4 | 470 | |
b15084ec | 471 | __IP_UPD_PO_STATS(net, IPSTATS_MIB_IN, skb->len); |
1da177e4 | 472 | |
51456b29 IM |
473 | skb = skb_share_check(skb, GFP_ATOMIC); |
474 | if (!skb) { | |
b45386ef | 475 | __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); |
1da177e4 LT |
476 | goto out; |
477 | } | |
478 | ||
33cba429 | 479 | drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; |
1da177e4 LT |
480 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
481 | goto inhdr_error; | |
482 | ||
eddc9ec5 | 483 | iph = ip_hdr(skb); |
1da177e4 LT |
484 | |
485 | /* | |
c67fa027 | 486 | * RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum. |
1da177e4 LT |
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) | |
58615242 | 497 | goto inhdr_error; |
1da177e4 | 498 | |
1f07d03e ED |
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); | |
98f61995 ED |
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)); | |
1f07d03e | 505 | |
1da177e4 LT |
506 | if (!pskb_may_pull(skb, iph->ihl*4)) |
507 | goto inhdr_error; | |
508 | ||
eddc9ec5 | 509 | iph = ip_hdr(skb); |
1da177e4 | 510 | |
e9c60422 | 511 | if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) |
6a5dc9e5 | 512 | goto csum_error; |
1da177e4 | 513 | |
b1a78b9b | 514 | len = iph_totlen(skb, iph); |
704aed53 | 515 | if (skb->len < len) { |
33cba429 | 516 | drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; |
b45386ef | 517 | __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS); |
704aed53 MC |
518 | goto drop; |
519 | } else if (len < (iph->ihl*4)) | |
58615242 | 520 | goto inhdr_error; |
1da177e4 | 521 | |
58615242 TG |
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)) { | |
b45386ef | 527 | __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS); |
58615242 | 528 | goto drop; |
1da177e4 LT |
529 | } |
530 | ||
6c57f045 | 531 | iph = ip_hdr(skb); |
21d1196a ED |
532 | skb->transport_header = skb->network_header + iph->ihl*4; |
533 | ||
53602f92 | 534 | /* Remove any debris in the socket control block */ |
d569f1d7 | 535 | memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); |
0b922b7a | 536 | IPCB(skb)->iif = skb->skb_iif; |
53602f92 | 537 | |
71f9dacd | 538 | /* Must drop socket now because of tproxy. */ |
cf7fbe66 JS |
539 | if (!skb_sk_is_prefetched(skb)) |
540 | skb_orphan(skb); | |
71f9dacd | 541 | |
17266ee9 | 542 | return skb; |
1da177e4 | 543 | |
6a5dc9e5 | 544 | csum_error: |
33cba429 | 545 | drop_reason = SKB_DROP_REASON_IP_CSUM; |
b45386ef | 546 | __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS); |
1da177e4 | 547 | inhdr_error: |
33cba429 MD |
548 | if (drop_reason == SKB_DROP_REASON_NOT_SPECIFIED) |
549 | drop_reason = SKB_DROP_REASON_IP_INHDR; | |
b45386ef | 550 | __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS); |
1da177e4 | 551 | drop: |
33cba429 | 552 | kfree_skb_reason(skb, drop_reason); |
1da177e4 | 553 | out: |
17266ee9 EC |
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; | |
fb1b6999 | 568 | |
17266ee9 EC |
569 | return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, |
570 | net, NULL, skb, dev, NULL, | |
571 | ip_rcv_finish); | |
572 | } | |
573 | ||
5fa12739 | 574 | static void ip_sublist_rcv_finish(struct list_head *head) |
17266ee9 EC |
575 | { |
576 | struct sk_buff *skb, *next; | |
577 | ||
0761680d | 578 | list_for_each_entry_safe(skb, next, head, list) { |
992cba7e | 579 | skb_list_del_init(skb); |
5fa12739 | 580 | dst_input(skb); |
0761680d | 581 | } |
5fa12739 EC |
582 | } |
583 | ||
02b24941 PA |
584 | static struct sk_buff *ip_extract_route_hint(const struct net *net, |
585 | struct sk_buff *skb, int rt_type) | |
586 | { | |
6ac66cb0 SY |
587 | if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST || |
588 | IPCB(skb)->flags & IPSKB_MULTIPATH) | |
02b24941 PA |
589 | return NULL; |
590 | ||
591 | return skb; | |
592 | } | |
593 | ||
5fa12739 EC |
594 | static void ip_list_rcv_finish(struct net *net, struct sock *sk, |
595 | struct list_head *head) | |
596 | { | |
02b24941 | 597 | struct sk_buff *skb, *next, *hint = NULL; |
5fa12739 | 598 | struct dst_entry *curr_dst = NULL; |
cecbe5c8 | 599 | LIST_HEAD(sublist); |
5fa12739 EC |
600 | |
601 | list_for_each_entry_safe(skb, next, head, list) { | |
a1fd1ad2 | 602 | struct net_device *dev = skb->dev; |
5fa12739 EC |
603 | struct dst_entry *dst; |
604 | ||
22f6bbb7 | 605 | skb_list_del_init(skb); |
efe6aaca EC |
606 | /* if ingress device is enslaved to an L3 master device pass the |
607 | * skb to its handler for processing | |
608 | */ | |
609 | skb = l3mdev_ip_rcv(skb); | |
610 | if (!skb) | |
611 | continue; | |
02b24941 | 612 | if (ip_rcv_finish_core(net, sk, skb, dev, hint) == NET_RX_DROP) |
5fa12739 EC |
613 | continue; |
614 | ||
615 | dst = skb_dst(skb); | |
616 | if (curr_dst != dst) { | |
02b24941 | 617 | hint = ip_extract_route_hint(net, skb, |
05d6d492 | 618 | dst_rtable(dst)->rt_type); |
02b24941 | 619 | |
5fa12739 | 620 | /* dispatch old sublist */ |
5fa12739 EC |
621 | if (!list_empty(&sublist)) |
622 | ip_sublist_rcv_finish(&sublist); | |
623 | /* start new sublist */ | |
a4ca8b7d | 624 | INIT_LIST_HEAD(&sublist); |
5fa12739 EC |
625 | curr_dst = dst; |
626 | } | |
a4ca8b7d | 627 | list_add_tail(&skb->list, &sublist); |
5fa12739 EC |
628 | } |
629 | /* dispatch final sublist */ | |
a4ca8b7d | 630 | ip_sublist_rcv_finish(&sublist); |
5fa12739 EC |
631 | } |
632 | ||
633 | static void ip_sublist_rcv(struct list_head *head, struct net_device *dev, | |
634 | struct net *net) | |
635 | { | |
17266ee9 EC |
636 | NF_HOOK_LIST(NFPROTO_IPV4, NF_INET_PRE_ROUTING, net, NULL, |
637 | head, dev, NULL, ip_rcv_finish); | |
5fa12739 | 638 | ip_list_rcv_finish(net, NULL, head); |
17266ee9 EC |
639 | } |
640 | ||
641 | /* Receive a list of IP packets */ | |
642 | void ip_list_rcv(struct list_head *head, struct packet_type *pt, | |
643 | struct net_device *orig_dev) | |
644 | { | |
645 | struct net_device *curr_dev = NULL; | |
646 | struct net *curr_net = NULL; | |
647 | struct sk_buff *skb, *next; | |
cecbe5c8 | 648 | LIST_HEAD(sublist); |
17266ee9 EC |
649 | |
650 | list_for_each_entry_safe(skb, next, head, list) { | |
651 | struct net_device *dev = skb->dev; | |
652 | struct net *net = dev_net(dev); | |
653 | ||
22f6bbb7 | 654 | skb_list_del_init(skb); |
17266ee9 EC |
655 | skb = ip_rcv_core(skb, net); |
656 | if (skb == NULL) | |
657 | continue; | |
658 | ||
659 | if (curr_dev != dev || curr_net != net) { | |
660 | /* dispatch old sublist */ | |
17266ee9 | 661 | if (!list_empty(&sublist)) |
a4ca8b7d | 662 | ip_sublist_rcv(&sublist, curr_dev, curr_net); |
17266ee9 | 663 | /* start new sublist */ |
a4ca8b7d | 664 | INIT_LIST_HEAD(&sublist); |
17266ee9 EC |
665 | curr_dev = dev; |
666 | curr_net = net; | |
667 | } | |
a4ca8b7d | 668 | list_add_tail(&skb->list, &sublist); |
17266ee9 EC |
669 | } |
670 | /* dispatch final sublist */ | |
51210ad5 FW |
671 | if (!list_empty(&sublist)) |
672 | ip_sublist_rcv(&sublist, curr_dev, curr_net); | |
1da177e4 | 673 | } |