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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv4/ip_input.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'net/ipv4/ip_input.c')
-rw-r--r--net/ipv4/ip_input.c431
1 files changed, 431 insertions, 0 deletions
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
new file mode 100644
index 000000000000..a0d0833034be
--- /dev/null
+++ b/net/ipv4/ip_input.c
@@ -0,0 +1,431 @@
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * The Internet Protocol (IP) module.
7 *
8 * Version: $Id: ip_input.c,v 1.55 2002/01/12 07:39:45 davem Exp $
9 *
10 * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Donald Becker, <becker@super.org>
13 * Alan Cox, <Alan.Cox@linux.org>
14 * Richard Underwood
15 * Stefan Becker, <stefanb@yello.ping.de>
16 * Jorge Cwik, <jorge@laser.satlink.net>
17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18 *
19 *
20 * Fixes:
21 * Alan Cox : Commented a couple of minor bits of surplus code
22 * Alan Cox : Undefining IP_FORWARD doesn't include the code
23 * (just stops a compiler warning).
24 * Alan Cox : Frames with >=MAX_ROUTE record routes, strict routes or loose routes
25 * are junked rather than corrupting things.
26 * Alan Cox : Frames to bad broadcast subnets are dumped
27 * We used to process them non broadcast and
28 * boy could that cause havoc.
29 * Alan Cox : ip_forward sets the free flag on the
30 * new frame it queues. Still crap because
31 * it copies the frame but at least it
32 * doesn't eat memory too.
33 * Alan Cox : Generic queue code and memory fixes.
34 * Fred Van Kempen : IP fragment support (borrowed from NET2E)
35 * Gerhard Koerting: Forward fragmented frames correctly.
36 * Gerhard Koerting: Fixes to my fix of the above 8-).
37 * Gerhard Koerting: IP interface addressing fix.
38 * Linus Torvalds : More robustness checks
39 * Alan Cox : Even more checks: Still not as robust as it ought to be
40 * Alan Cox : Save IP header pointer for later
41 * Alan Cox : ip option setting
42 * Alan Cox : Use ip_tos/ip_ttl settings
43 * Alan Cox : Fragmentation bogosity removed
44 * (Thanks to Mark.Bush@prg.ox.ac.uk)
45 * Dmitry Gorodchanin : Send of a raw packet crash fix.
46 * Alan Cox : Silly ip bug when an overlength
47 * fragment turns up. Now frees the
48 * queue.
49 * Linus Torvalds/ : Memory leakage on fragmentation
50 * Alan Cox : handling.
51 * Gerhard Koerting: Forwarding uses IP priority hints
52 * Teemu Rantanen : Fragment problems.
53 * Alan Cox : General cleanup, comments and reformat
54 * Alan Cox : SNMP statistics
55 * Alan Cox : BSD address rule semantics. Also see
56 * UDP as there is a nasty checksum issue
57 * if you do things the wrong way.
58 * Alan Cox : Always defrag, moved IP_FORWARD to the config.in file
59 * Alan Cox : IP options adjust sk->priority.
60 * Pedro Roque : Fix mtu/length error in ip_forward.
61 * Alan Cox : Avoid ip_chk_addr when possible.
62 * Richard Underwood : IP multicasting.
63 * Alan Cox : Cleaned up multicast handlers.
64 * Alan Cox : RAW sockets demultiplex in the BSD style.
65 * Gunther Mayer : Fix the SNMP reporting typo
66 * Alan Cox : Always in group 224.0.0.1
67 * Pauline Middelink : Fast ip_checksum update when forwarding
68 * Masquerading support.
69 * Alan Cox : Multicast loopback error for 224.0.0.1
70 * Alan Cox : IP_MULTICAST_LOOP option.
71 * Alan Cox : Use notifiers.
72 * Bjorn Ekwall : Removed ip_csum (from slhc.c too)
73 * Bjorn Ekwall : Moved ip_fast_csum to ip.h (inline!)
74 * Stefan Becker : Send out ICMP HOST REDIRECT
75 * Arnt Gulbrandsen : ip_build_xmit
76 * Alan Cox : Per socket routing cache
77 * Alan Cox : Fixed routing cache, added header cache.
78 * Alan Cox : Loopback didn't work right in original ip_build_xmit - fixed it.
79 * Alan Cox : Only send ICMP_REDIRECT if src/dest are the same net.
80 * Alan Cox : Incoming IP option handling.
81 * Alan Cox : Set saddr on raw output frames as per BSD.
82 * Alan Cox : Stopped broadcast source route explosions.
83 * Alan Cox : Can disable source routing
84 * Takeshi Sone : Masquerading didn't work.
85 * Dave Bonn,Alan Cox : Faster IP forwarding whenever possible.
86 * Alan Cox : Memory leaks, tramples, misc debugging.
87 * Alan Cox : Fixed multicast (by popular demand 8))
88 * Alan Cox : Fixed forwarding (by even more popular demand 8))
89 * Alan Cox : Fixed SNMP statistics [I think]
90 * Gerhard Koerting : IP fragmentation forwarding fix
91 * Alan Cox : Device lock against page fault.
92 * Alan Cox : IP_HDRINCL facility.
93 * Werner Almesberger : Zero fragment bug
94 * Alan Cox : RAW IP frame length bug
95 * Alan Cox : Outgoing firewall on build_xmit
96 * A.N.Kuznetsov : IP_OPTIONS support throughout the kernel
97 * Alan Cox : Multicast routing hooks
98 * Jos Vos : Do accounting *before* call_in_firewall
99 * Willy Konynenberg : Transparent proxying support
100 *
101 *
102 *
103 * To Fix:
104 * IP fragmentation wants rewriting cleanly. The RFC815 algorithm is much more efficient
105 * and could be made very efficient with the addition of some virtual memory hacks to permit
106 * the allocation of a buffer that can then be 'grown' by twiddling page tables.
107 * Output fragmentation wants updating along with the buffer management to use a single
108 * interleaved copy algorithm so that fragmenting has a one copy overhead. Actual packet
109 * output should probably do its own fragmentation at the UDP/RAW layer. TCP shouldn't cause
110 * fragmentation anyway.
111 *
112 * This program is free software; you can redistribute it and/or
113 * modify it under the terms of the GNU General Public License
114 * as published by the Free Software Foundation; either version
115 * 2 of the License, or (at your option) any later version.
116 */
117
118#include <asm/system.h>
119#include <linux/module.h>
120#include <linux/types.h>
121#include <linux/kernel.h>
122#include <linux/string.h>
123#include <linux/errno.h>
124#include <linux/config.h>
125
126#include <linux/net.h>
127#include <linux/socket.h>
128#include <linux/sockios.h>
129#include <linux/in.h>
130#include <linux/inet.h>
131#include <linux/netdevice.h>
132#include <linux/etherdevice.h>
133
134#include <net/snmp.h>
135#include <net/ip.h>
136#include <net/protocol.h>
137#include <net/route.h>
138#include <linux/skbuff.h>
139#include <net/sock.h>
140#include <net/arp.h>
141#include <net/icmp.h>
142#include <net/raw.h>
143#include <net/checksum.h>
144#include <linux/netfilter_ipv4.h>
145#include <net/xfrm.h>
146#include <linux/mroute.h>
147#include <linux/netlink.h>
148
149/*
150 * SNMP management statistics
151 */
152
153DEFINE_SNMP_STAT(struct ipstats_mib, ip_statistics);
154
155/*
156 * Process Router Attention IP option
157 */
158int ip_call_ra_chain(struct sk_buff *skb)
159{
160 struct ip_ra_chain *ra;
161 u8 protocol = skb->nh.iph->protocol;
162 struct sock *last = NULL;
163
164 read_lock(&ip_ra_lock);
165 for (ra = ip_ra_chain; ra; ra = ra->next) {
166 struct sock *sk = ra->sk;
167
168 /* If socket is bound to an interface, only report
169 * the packet if it came from that interface.
170 */
171 if (sk && inet_sk(sk)->num == protocol &&
172 (!sk->sk_bound_dev_if ||
173 sk->sk_bound_dev_if == skb->dev->ifindex)) {
174 if (skb->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
175 skb = ip_defrag(skb, IP_DEFRAG_CALL_RA_CHAIN);
176 if (skb == NULL) {
177 read_unlock(&ip_ra_lock);
178 return 1;
179 }
180 }
181 if (last) {
182 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
183 if (skb2)
184 raw_rcv(last, skb2);
185 }
186 last = sk;
187 }
188 }
189
190 if (last) {
191 raw_rcv(last, skb);
192 read_unlock(&ip_ra_lock);
193 return 1;
194 }
195 read_unlock(&ip_ra_lock);
196 return 0;
197}
198
199static inline int ip_local_deliver_finish(struct sk_buff *skb)
200{
201 int ihl = skb->nh.iph->ihl*4;
202
203#ifdef CONFIG_NETFILTER_DEBUG
204 nf_debug_ip_local_deliver(skb);
205#endif /*CONFIG_NETFILTER_DEBUG*/
206
207 __skb_pull(skb, ihl);
208
209 /* Free reference early: we don't need it any more, and it may
210 hold ip_conntrack module loaded indefinitely. */
211 nf_reset(skb);
212
213 /* Point into the IP datagram, just past the header. */
214 skb->h.raw = skb->data;
215
216 rcu_read_lock();
217 {
218 /* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */
219 int protocol = skb->nh.iph->protocol;
220 int hash;
221 struct sock *raw_sk;
222 struct net_protocol *ipprot;
223
224 resubmit:
225 hash = protocol & (MAX_INET_PROTOS - 1);
226 raw_sk = sk_head(&raw_v4_htable[hash]);
227
228 /* If there maybe a raw socket we must check - if not we
229 * don't care less
230 */
231 if (raw_sk)
232 raw_v4_input(skb, skb->nh.iph, hash);
233
234 if ((ipprot = rcu_dereference(inet_protos[hash])) != NULL) {
235 int ret;
236
237 if (!ipprot->no_policy &&
238 !xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
239 kfree_skb(skb);
240 goto out;
241 }
242 ret = ipprot->handler(skb);
243 if (ret < 0) {
244 protocol = -ret;
245 goto resubmit;
246 }
247 IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
248 } else {
249 if (!raw_sk) {
250 if (xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
251 IP_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS);
252 icmp_send(skb, ICMP_DEST_UNREACH,
253 ICMP_PROT_UNREACH, 0);
254 }
255 } else
256 IP_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
257 kfree_skb(skb);
258 }
259 }
260 out:
261 rcu_read_unlock();
262
263 return 0;
264}
265
266/*
267 * Deliver IP Packets to the higher protocol layers.
268 */
269int ip_local_deliver(struct sk_buff *skb)
270{
271 /*
272 * Reassemble IP fragments.
273 */
274
275 if (skb->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
276 skb = ip_defrag(skb, IP_DEFRAG_LOCAL_DELIVER);
277 if (!skb)
278 return 0;
279 }
280
281 return NF_HOOK(PF_INET, NF_IP_LOCAL_IN, skb, skb->dev, NULL,
282 ip_local_deliver_finish);
283}
284
285static inline int ip_rcv_finish(struct sk_buff *skb)
286{
287 struct net_device *dev = skb->dev;
288 struct iphdr *iph = skb->nh.iph;
289
290 /*
291 * Initialise the virtual path cache for the packet. It describes
292 * how the packet travels inside Linux networking.
293 */
294 if (skb->dst == NULL) {
295 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))
296 goto drop;
297 }
298
299#ifdef CONFIG_NET_CLS_ROUTE
300 if (skb->dst->tclassid) {
301 struct ip_rt_acct *st = ip_rt_acct + 256*smp_processor_id();
302 u32 idx = skb->dst->tclassid;
303 st[idx&0xFF].o_packets++;
304 st[idx&0xFF].o_bytes+=skb->len;
305 st[(idx>>16)&0xFF].i_packets++;
306 st[(idx>>16)&0xFF].i_bytes+=skb->len;
307 }
308#endif
309
310 if (iph->ihl > 5) {
311 struct ip_options *opt;
312
313 /* It looks as overkill, because not all
314 IP options require packet mangling.
315 But it is the easiest for now, especially taking
316 into account that combination of IP options
317 and running sniffer is extremely rare condition.
318 --ANK (980813)
319 */
320
321 if (skb_cow(skb, skb_headroom(skb))) {
322 IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
323 goto drop;
324 }
325 iph = skb->nh.iph;
326
327 if (ip_options_compile(NULL, skb))
328 goto inhdr_error;
329
330 opt = &(IPCB(skb)->opt);
331 if (opt->srr) {
332 struct in_device *in_dev = in_dev_get(dev);
333 if (in_dev) {
334 if (!IN_DEV_SOURCE_ROUTE(in_dev)) {
335 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit())
336 printk(KERN_INFO "source route option %u.%u.%u.%u -> %u.%u.%u.%u\n",
337 NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
338 in_dev_put(in_dev);
339 goto drop;
340 }
341 in_dev_put(in_dev);
342 }
343 if (ip_options_rcv_srr(skb))
344 goto drop;
345 }
346 }
347
348 return dst_input(skb);
349
350inhdr_error:
351 IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
352drop:
353 kfree_skb(skb);
354 return NET_RX_DROP;
355}
356
357/*
358 * Main IP Receive routine.
359 */
360int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
361{
362 struct iphdr *iph;
363
364 /* When the interface is in promisc. mode, drop all the crap
365 * that it receives, do not try to analyse it.
366 */
367 if (skb->pkt_type == PACKET_OTHERHOST)
368 goto drop;
369
370 IP_INC_STATS_BH(IPSTATS_MIB_INRECEIVES);
371
372 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
373 IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
374 goto out;
375 }
376
377 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
378 goto inhdr_error;
379
380 iph = skb->nh.iph;
381
382 /*
383 * RFC1122: 3.1.2.2 MUST silently discard any IP frame that fails the checksum.
384 *
385 * Is the datagram acceptable?
386 *
387 * 1. Length at least the size of an ip header
388 * 2. Version of 4
389 * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums]
390 * 4. Doesn't have a bogus length
391 */
392
393 if (iph->ihl < 5 || iph->version != 4)
394 goto inhdr_error;
395
396 if (!pskb_may_pull(skb, iph->ihl*4))
397 goto inhdr_error;
398
399 iph = skb->nh.iph;
400
401 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
402 goto inhdr_error;
403
404 {
405 __u32 len = ntohs(iph->tot_len);
406 if (skb->len < len || len < (iph->ihl<<2))
407 goto inhdr_error;
408
409 /* Our transport medium may have padded the buffer out. Now we know it
410 * is IP we can trim to the true length of the frame.
411 * Note this now means skb->len holds ntohs(iph->tot_len).
412 */
413 if (pskb_trim_rcsum(skb, len)) {
414 IP_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
415 goto drop;
416 }
417 }
418
419 return NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, dev, NULL,
420 ip_rcv_finish);
421
422inhdr_error:
423 IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
424drop:
425 kfree_skb(skb);
426out:
427 return NET_RX_DROP;
428}
429
430EXPORT_SYMBOL(ip_rcv);
431EXPORT_SYMBOL(ip_statistics);