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ipv6: Early TCP socket demux
[linux-2.6.git] / net / ipv4 / route.c
blobfc1a81ca79a7837d4307cb2a9bb034630c99b1a2
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 * ROUTE - implementation of the IP router.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox, <gw4pts@gw4pts.ampr.org>
11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
13 *
14 * Fixes:
15 * Alan Cox : Verify area fixes.
16 * Alan Cox : cli() protects routing changes
17 * Rui Oliveira : ICMP routing table updates
18 * (rco@di.uminho.pt) Routing table insertion and update
19 * Linus Torvalds : Rewrote bits to be sensible
20 * Alan Cox : Added BSD route gw semantics
21 * Alan Cox : Super /proc >4K
22 * Alan Cox : MTU in route table
23 * Alan Cox : MSS actually. Also added the window
24 * clamper.
25 * Sam Lantinga : Fixed route matching in rt_del()
26 * Alan Cox : Routing cache support.
27 * Alan Cox : Removed compatibility cruft.
28 * Alan Cox : RTF_REJECT support.
29 * Alan Cox : TCP irtt support.
30 * Jonathan Naylor : Added Metric support.
31 * Miquel van Smoorenburg : BSD API fixes.
32 * Miquel van Smoorenburg : Metrics.
33 * Alan Cox : Use __u32 properly
34 * Alan Cox : Aligned routing errors more closely with BSD
35 * our system is still very different.
36 * Alan Cox : Faster /proc handling
37 * Alexey Kuznetsov : Massive rework to support tree based routing,
38 * routing caches and better behaviour.
39 *
40 * Olaf Erb : irtt wasn't being copied right.
41 * Bjorn Ekwall : Kerneld route support.
42 * Alan Cox : Multicast fixed (I hope)
43 * Pavel Krauz : Limited broadcast fixed
44 * Mike McLagan : Routing by source
45 * Alexey Kuznetsov : End of old history. Split to fib.c and
46 * route.c and rewritten from scratch.
47 * Andi Kleen : Load-limit warning messages.
48 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
52 * Marc Boucher : routing by fwmark
53 * Robert Olsson : Added rt_cache statistics
54 * Arnaldo C. Melo : Convert proc stuff to seq_file
55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
57 * Ilia Sotnikov : Removed TOS from hash calculations
58 *
59 * This program is free software; you can redistribute it and/or
60 * modify it under the terms of the GNU General Public License
61 * as published by the Free Software Foundation; either version
62 * 2 of the License, or (at your option) any later version.
63 */
64
65 #define pr_fmt(fmt) "IPv4: " fmt
66
67 #include <linux/module.h>
68 #include <asm/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/types.h>
71 #include <linux/kernel.h>
72 #include <linux/mm.h>
73 #include <linux/bootmem.h>
74 #include <linux/string.h>
75 #include <linux/socket.h>
76 #include <linux/sockios.h>
77 #include <linux/errno.h>
78 #include <linux/in.h>
79 #include <linux/inet.h>
80 #include <linux/netdevice.h>
81 #include <linux/proc_fs.h>
82 #include <linux/init.h>
83 #include <linux/workqueue.h>
84 #include <linux/skbuff.h>
85 #include <linux/inetdevice.h>
86 #include <linux/igmp.h>
87 #include <linux/pkt_sched.h>
88 #include <linux/mroute.h>
89 #include <linux/netfilter_ipv4.h>
90 #include <linux/random.h>
91 #include <linux/jhash.h>
92 #include <linux/rcupdate.h>
93 #include <linux/times.h>
94 #include <linux/slab.h>
95 #include <linux/prefetch.h>
96 #include <net/dst.h>
97 #include <net/net_namespace.h>
98 #include <net/protocol.h>
99 #include <net/ip.h>
100 #include <net/route.h>
101 #include <net/inetpeer.h>
102 #include <net/sock.h>
103 #include <net/ip_fib.h>
104 #include <net/arp.h>
105 #include <net/tcp.h>
106 #include <net/icmp.h>
107 #include <net/xfrm.h>
108 #include <net/netevent.h>
109 #include <net/rtnetlink.h>
110 #ifdef CONFIG_SYSCTL
111 #include <linux/sysctl.h>
112 #include <linux/kmemleak.h>
113 #endif
114 #include <net/secure_seq.h>
115
116 #define RT_FL_TOS(oldflp4) \
117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
118
119 #define IP_MAX_MTU 0xFFF0
120
121 #define RT_GC_TIMEOUT (300*HZ)
122
123 static int ip_rt_max_size;
124 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
125 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
126 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
127 static int ip_rt_redirect_number __read_mostly = 9;
128 static int ip_rt_redirect_load __read_mostly = HZ / 50;
129 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
130 static int ip_rt_error_cost __read_mostly = HZ;
131 static int ip_rt_error_burst __read_mostly = 5 * HZ;
132 static int ip_rt_gc_elasticity __read_mostly = 8;
133 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
134 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
135 static int ip_rt_min_advmss __read_mostly = 256;
136
137 /*
138 * Interface to generic destination cache.
139 */
140
141 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
142 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
143 static unsigned int ipv4_mtu(const struct dst_entry *dst);
144 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
145 static void ipv4_link_failure(struct sk_buff *skb);
146 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
147 struct sk_buff *skb, u32 mtu);
148 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
149 struct sk_buff *skb);
150
151 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
152 int how)
153 {
154 }
155
156 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
157 {
158 WARN_ON(1);
159 return NULL;
160 }
161
162 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
163 struct sk_buff *skb,
164 const void *daddr);
165
166 static struct dst_ops ipv4_dst_ops = {
167 .family = AF_INET,
168 .protocol = cpu_to_be16(ETH_P_IP),
169 .check = ipv4_dst_check,
170 .default_advmss = ipv4_default_advmss,
171 .mtu = ipv4_mtu,
172 .cow_metrics = ipv4_cow_metrics,
173 .ifdown = ipv4_dst_ifdown,
174 .negative_advice = ipv4_negative_advice,
175 .link_failure = ipv4_link_failure,
176 .update_pmtu = ip_rt_update_pmtu,
177 .redirect = ip_do_redirect,
178 .local_out = __ip_local_out,
179 .neigh_lookup = ipv4_neigh_lookup,
180 };
181
182 #define ECN_OR_COST(class) TC_PRIO_##class
183
184 const __u8 ip_tos2prio[16] = {
185 TC_PRIO_BESTEFFORT,
186 ECN_OR_COST(BESTEFFORT),
187 TC_PRIO_BESTEFFORT,
188 ECN_OR_COST(BESTEFFORT),
189 TC_PRIO_BULK,
190 ECN_OR_COST(BULK),
191 TC_PRIO_BULK,
192 ECN_OR_COST(BULK),
193 TC_PRIO_INTERACTIVE,
194 ECN_OR_COST(INTERACTIVE),
195 TC_PRIO_INTERACTIVE,
196 ECN_OR_COST(INTERACTIVE),
197 TC_PRIO_INTERACTIVE_BULK,
198 ECN_OR_COST(INTERACTIVE_BULK),
199 TC_PRIO_INTERACTIVE_BULK,
200 ECN_OR_COST(INTERACTIVE_BULK)
201 };
202 EXPORT_SYMBOL(ip_tos2prio);
203
204 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
205 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
206
207 static inline int rt_genid(struct net *net)
208 {
209 return atomic_read(&net->ipv4.rt_genid);
210 }
211
212 #ifdef CONFIG_PROC_FS
213 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
214 {
215 if (*pos)
216 return NULL;
217 return SEQ_START_TOKEN;
218 }
219
220 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
221 {
222 ++*pos;
223 return NULL;
224 }
225
226 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
227 {
228 }
229
230 static int rt_cache_seq_show(struct seq_file *seq, void *v)
231 {
232 if (v == SEQ_START_TOKEN)
233 seq_printf(seq, "%-127s\n",
234 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
235 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
236 "HHUptod\tSpecDst");
237 return 0;
238 }
239
240 static const struct seq_operations rt_cache_seq_ops = {
241 .start = rt_cache_seq_start,
242 .next = rt_cache_seq_next,
243 .stop = rt_cache_seq_stop,
244 .show = rt_cache_seq_show,
245 };
246
247 static int rt_cache_seq_open(struct inode *inode, struct file *file)
248 {
249 return seq_open(file, &rt_cache_seq_ops);
250 }
251
252 static const struct file_operations rt_cache_seq_fops = {
253 .owner = THIS_MODULE,
254 .open = rt_cache_seq_open,
255 .read = seq_read,
256 .llseek = seq_lseek,
257 .release = seq_release,
258 };
259
260
261 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
262 {
263 int cpu;
264
265 if (*pos == 0)
266 return SEQ_START_TOKEN;
267
268 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
269 if (!cpu_possible(cpu))
270 continue;
271 *pos = cpu+1;
272 return &per_cpu(rt_cache_stat, cpu);
273 }
274 return NULL;
275 }
276
277 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
278 {
279 int cpu;
280
281 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
282 if (!cpu_possible(cpu))
283 continue;
284 *pos = cpu+1;
285 return &per_cpu(rt_cache_stat, cpu);
286 }
287 return NULL;
288
289 }
290
291 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
292 {
293
294 }
295
296 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
297 {
298 struct rt_cache_stat *st = v;
299
300 if (v == SEQ_START_TOKEN) {
301 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
302 return 0;
303 }
304
305 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
306 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
307 dst_entries_get_slow(&ipv4_dst_ops),
308 st->in_hit,
309 st->in_slow_tot,
310 st->in_slow_mc,
311 st->in_no_route,
312 st->in_brd,
313 st->in_martian_dst,
314 st->in_martian_src,
315
316 st->out_hit,
317 st->out_slow_tot,
318 st->out_slow_mc,
319
320 st->gc_total,
321 st->gc_ignored,
322 st->gc_goal_miss,
323 st->gc_dst_overflow,
324 st->in_hlist_search,
325 st->out_hlist_search
326 );
327 return 0;
328 }
329
330 static const struct seq_operations rt_cpu_seq_ops = {
331 .start = rt_cpu_seq_start,
332 .next = rt_cpu_seq_next,
333 .stop = rt_cpu_seq_stop,
334 .show = rt_cpu_seq_show,
335 };
336
337
338 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
339 {
340 return seq_open(file, &rt_cpu_seq_ops);
341 }
342
343 static const struct file_operations rt_cpu_seq_fops = {
344 .owner = THIS_MODULE,
345 .open = rt_cpu_seq_open,
346 .read = seq_read,
347 .llseek = seq_lseek,
348 .release = seq_release,
349 };
350
351 #ifdef CONFIG_IP_ROUTE_CLASSID
352 static int rt_acct_proc_show(struct seq_file *m, void *v)
353 {
354 struct ip_rt_acct *dst, *src;
355 unsigned int i, j;
356
357 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
358 if (!dst)
359 return -ENOMEM;
360
361 for_each_possible_cpu(i) {
362 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
363 for (j = 0; j < 256; j++) {
364 dst[j].o_bytes += src[j].o_bytes;
365 dst[j].o_packets += src[j].o_packets;
366 dst[j].i_bytes += src[j].i_bytes;
367 dst[j].i_packets += src[j].i_packets;
368 }
369 }
370
371 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
372 kfree(dst);
373 return 0;
374 }
375
376 static int rt_acct_proc_open(struct inode *inode, struct file *file)
377 {
378 return single_open(file, rt_acct_proc_show, NULL);
379 }
380
381 static const struct file_operations rt_acct_proc_fops = {
382 .owner = THIS_MODULE,
383 .open = rt_acct_proc_open,
384 .read = seq_read,
385 .llseek = seq_lseek,
386 .release = single_release,
387 };
388 #endif
389
390 static int __net_init ip_rt_do_proc_init(struct net *net)
391 {
392 struct proc_dir_entry *pde;
393
394 pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
395 &rt_cache_seq_fops);
396 if (!pde)
397 goto err1;
398
399 pde = proc_create("rt_cache", S_IRUGO,
400 net->proc_net_stat, &rt_cpu_seq_fops);
401 if (!pde)
402 goto err2;
403
404 #ifdef CONFIG_IP_ROUTE_CLASSID
405 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
406 if (!pde)
407 goto err3;
408 #endif
409 return 0;
410
411 #ifdef CONFIG_IP_ROUTE_CLASSID
412 err3:
413 remove_proc_entry("rt_cache", net->proc_net_stat);
414 #endif
415 err2:
416 remove_proc_entry("rt_cache", net->proc_net);
417 err1:
418 return -ENOMEM;
419 }
420
421 static void __net_exit ip_rt_do_proc_exit(struct net *net)
422 {
423 remove_proc_entry("rt_cache", net->proc_net_stat);
424 remove_proc_entry("rt_cache", net->proc_net);
425 #ifdef CONFIG_IP_ROUTE_CLASSID
426 remove_proc_entry("rt_acct", net->proc_net);
427 #endif
428 }
429
430 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
431 .init = ip_rt_do_proc_init,
432 .exit = ip_rt_do_proc_exit,
433 };
434
435 static int __init ip_rt_proc_init(void)
436 {
437 return register_pernet_subsys(&ip_rt_proc_ops);
438 }
439
440 #else
441 static inline int ip_rt_proc_init(void)
442 {
443 return 0;
444 }
445 #endif /* CONFIG_PROC_FS */
446
447 static inline bool rt_is_expired(const struct rtable *rth)
448 {
449 return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
450 }
451
452 /*
453 * Perturbation of rt_genid by a small quantity [1..256]
454 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
455 * many times (2^24) without giving recent rt_genid.
456 * Jenkins hash is strong enough that litle changes of rt_genid are OK.
457 */
458 static void rt_cache_invalidate(struct net *net)
459 {
460 unsigned char shuffle;
461
462 get_random_bytes(&shuffle, sizeof(shuffle));
463 atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
464 }
465
466 /*
467 * delay < 0 : invalidate cache (fast : entries will be deleted later)
468 * delay >= 0 : invalidate & flush cache (can be long)
469 */
470 void rt_cache_flush(struct net *net, int delay)
471 {
472 rt_cache_invalidate(net);
473 }
474
475 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
476 struct sk_buff *skb,
477 const void *daddr)
478 {
479 struct net_device *dev = dst->dev;
480 const __be32 *pkey = daddr;
481 const struct rtable *rt;
482 struct neighbour *n;
483
484 rt = (const struct rtable *) dst;
485 if (rt->rt_gateway)
486 pkey = (const __be32 *) &rt->rt_gateway;
487 else if (skb)
488 pkey = &ip_hdr(skb)->daddr;
489
490 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
491 if (n)
492 return n;
493 return neigh_create(&arp_tbl, pkey, dev);
494 }
495
496 /*
497 * Peer allocation may fail only in serious out-of-memory conditions. However
498 * we still can generate some output.
499 * Random ID selection looks a bit dangerous because we have no chances to
500 * select ID being unique in a reasonable period of time.
501 * But broken packet identifier may be better than no packet at all.
502 */
503 static void ip_select_fb_ident(struct iphdr *iph)
504 {
505 static DEFINE_SPINLOCK(ip_fb_id_lock);
506 static u32 ip_fallback_id;
507 u32 salt;
508
509 spin_lock_bh(&ip_fb_id_lock);
510 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
511 iph->id = htons(salt & 0xFFFF);
512 ip_fallback_id = salt;
513 spin_unlock_bh(&ip_fb_id_lock);
514 }
515
516 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
517 {
518 struct net *net = dev_net(dst->dev);
519 struct inet_peer *peer;
520
521 peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
522 if (peer) {
523 iph->id = htons(inet_getid(peer, more));
524 inet_putpeer(peer);
525 return;
526 }
527
528 ip_select_fb_ident(iph);
529 }
530 EXPORT_SYMBOL(__ip_select_ident);
531
532 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
533 const struct iphdr *iph,
534 int oif, u8 tos,
535 u8 prot, u32 mark, int flow_flags)
536 {
537 if (sk) {
538 const struct inet_sock *inet = inet_sk(sk);
539
540 oif = sk->sk_bound_dev_if;
541 mark = sk->sk_mark;
542 tos = RT_CONN_FLAGS(sk);
543 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
544 }
545 flowi4_init_output(fl4, oif, mark, tos,
546 RT_SCOPE_UNIVERSE, prot,
547 flow_flags,
548 iph->daddr, iph->saddr, 0, 0);
549 }
550
551 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
552 const struct sock *sk)
553 {
554 const struct iphdr *iph = ip_hdr(skb);
555 int oif = skb->dev->ifindex;
556 u8 tos = RT_TOS(iph->tos);
557 u8 prot = iph->protocol;
558 u32 mark = skb->mark;
559
560 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
561 }
562
563 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
564 {
565 const struct inet_sock *inet = inet_sk(sk);
566 const struct ip_options_rcu *inet_opt;
567 __be32 daddr = inet->inet_daddr;
568
569 rcu_read_lock();
570 inet_opt = rcu_dereference(inet->inet_opt);
571 if (inet_opt && inet_opt->opt.srr)
572 daddr = inet_opt->opt.faddr;
573 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
574 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
575 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
576 inet_sk_flowi_flags(sk),
577 daddr, inet->inet_saddr, 0, 0);
578 rcu_read_unlock();
579 }
580
581 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
582 const struct sk_buff *skb)
583 {
584 if (skb)
585 build_skb_flow_key(fl4, skb, sk);
586 else
587 build_sk_flow_key(fl4, sk);
588 }
589
590 static DEFINE_SEQLOCK(fnhe_seqlock);
591
592 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
593 {
594 struct fib_nh_exception *fnhe, *oldest;
595
596 oldest = rcu_dereference(hash->chain);
597 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
598 fnhe = rcu_dereference(fnhe->fnhe_next)) {
599 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
600 oldest = fnhe;
601 }
602 return oldest;
603 }
604
605 static inline u32 fnhe_hashfun(__be32 daddr)
606 {
607 u32 hval;
608
609 hval = (__force u32) daddr;
610 hval ^= (hval >> 11) ^ (hval >> 22);
611
612 return hval & (FNHE_HASH_SIZE - 1);
613 }
614
615 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
616 u32 pmtu, unsigned long expires)
617 {
618 struct fnhe_hash_bucket *hash;
619 struct fib_nh_exception *fnhe;
620 int depth;
621 u32 hval = fnhe_hashfun(daddr);
622
623 write_seqlock_bh(&fnhe_seqlock);
624
625 hash = nh->nh_exceptions;
626 if (!hash) {
627 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
628 if (!hash)
629 goto out_unlock;
630 nh->nh_exceptions = hash;
631 }
632
633 hash += hval;
634
635 depth = 0;
636 for (fnhe = rcu_dereference(hash->chain); fnhe;
637 fnhe = rcu_dereference(fnhe->fnhe_next)) {
638 if (fnhe->fnhe_daddr == daddr)
639 break;
640 depth++;
641 }
642
643 if (fnhe) {
644 if (gw)
645 fnhe->fnhe_gw = gw;
646 if (pmtu) {
647 fnhe->fnhe_pmtu = pmtu;
648 fnhe->fnhe_expires = expires;
649 }
650 } else {
651 if (depth > FNHE_RECLAIM_DEPTH)
652 fnhe = fnhe_oldest(hash);
653 else {
654 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
655 if (!fnhe)
656 goto out_unlock;
657
658 fnhe->fnhe_next = hash->chain;
659 rcu_assign_pointer(hash->chain, fnhe);
660 }
661 fnhe->fnhe_daddr = daddr;
662 fnhe->fnhe_gw = gw;
663 fnhe->fnhe_pmtu = pmtu;
664 fnhe->fnhe_expires = expires;
665 }
666
667 fnhe->fnhe_stamp = jiffies;
668
669 out_unlock:
670 write_sequnlock_bh(&fnhe_seqlock);
671 return;
672 }
673
674 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
675 bool kill_route)
676 {
677 __be32 new_gw = icmp_hdr(skb)->un.gateway;
678 __be32 old_gw = ip_hdr(skb)->saddr;
679 struct net_device *dev = skb->dev;
680 struct in_device *in_dev;
681 struct fib_result res;
682 struct neighbour *n;
683 struct net *net;
684
685 switch (icmp_hdr(skb)->code & 7) {
686 case ICMP_REDIR_NET:
687 case ICMP_REDIR_NETTOS:
688 case ICMP_REDIR_HOST:
689 case ICMP_REDIR_HOSTTOS:
690 break;
691
692 default:
693 return;
694 }
695
696 if (rt->rt_gateway != old_gw)
697 return;
698
699 in_dev = __in_dev_get_rcu(dev);
700 if (!in_dev)
701 return;
702
703 net = dev_net(dev);
704 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
705 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
706 ipv4_is_zeronet(new_gw))
707 goto reject_redirect;
708
709 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
710 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
711 goto reject_redirect;
712 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
713 goto reject_redirect;
714 } else {
715 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
716 goto reject_redirect;
717 }
718
719 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
720 if (n) {
721 if (!(n->nud_state & NUD_VALID)) {
722 neigh_event_send(n, NULL);
723 } else {
724 if (fib_lookup(net, fl4, &res) == 0) {
725 struct fib_nh *nh = &FIB_RES_NH(res);
726
727 update_or_create_fnhe(nh, fl4->daddr, new_gw,
728 0, 0);
729 }
730 if (kill_route)
731 rt->dst.obsolete = DST_OBSOLETE_KILL;
732 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
733 }
734 neigh_release(n);
735 }
736 return;
737
738 reject_redirect:
739 #ifdef CONFIG_IP_ROUTE_VERBOSE
740 if (IN_DEV_LOG_MARTIANS(in_dev)) {
741 const struct iphdr *iph = (const struct iphdr *) skb->data;
742 __be32 daddr = iph->daddr;
743 __be32 saddr = iph->saddr;
744
745 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
746 " Advised path = %pI4 -> %pI4\n",
747 &old_gw, dev->name, &new_gw,
748 &saddr, &daddr);
749 }
750 #endif
751 ;
752 }
753
754 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
755 {
756 struct rtable *rt;
757 struct flowi4 fl4;
758
759 rt = (struct rtable *) dst;
760
761 ip_rt_build_flow_key(&fl4, sk, skb);
762 __ip_do_redirect(rt, skb, &fl4, true);
763 }
764
765 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
766 {
767 struct rtable *rt = (struct rtable *)dst;
768 struct dst_entry *ret = dst;
769
770 if (rt) {
771 if (dst->obsolete > 0) {
772 ip_rt_put(rt);
773 ret = NULL;
774 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
775 rt->dst.expires) {
776 ip_rt_put(rt);
777 ret = NULL;
778 }
779 }
780 return ret;
781 }
782
783 /*
784 * Algorithm:
785 * 1. The first ip_rt_redirect_number redirects are sent
786 * with exponential backoff, then we stop sending them at all,
787 * assuming that the host ignores our redirects.
788 * 2. If we did not see packets requiring redirects
789 * during ip_rt_redirect_silence, we assume that the host
790 * forgot redirected route and start to send redirects again.
791 *
792 * This algorithm is much cheaper and more intelligent than dumb load limiting
793 * in icmp.c.
794 *
795 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
796 * and "frag. need" (breaks PMTU discovery) in icmp.c.
797 */
798
799 void ip_rt_send_redirect(struct sk_buff *skb)
800 {
801 struct rtable *rt = skb_rtable(skb);
802 struct in_device *in_dev;
803 struct inet_peer *peer;
804 struct net *net;
805 int log_martians;
806
807 rcu_read_lock();
808 in_dev = __in_dev_get_rcu(rt->dst.dev);
809 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
810 rcu_read_unlock();
811 return;
812 }
813 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
814 rcu_read_unlock();
815
816 net = dev_net(rt->dst.dev);
817 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
818 if (!peer) {
819 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
820 return;
821 }
822
823 /* No redirected packets during ip_rt_redirect_silence;
824 * reset the algorithm.
825 */
826 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
827 peer->rate_tokens = 0;
828
829 /* Too many ignored redirects; do not send anything
830 * set dst.rate_last to the last seen redirected packet.
831 */
832 if (peer->rate_tokens >= ip_rt_redirect_number) {
833 peer->rate_last = jiffies;
834 goto out_put_peer;
835 }
836
837 /* Check for load limit; set rate_last to the latest sent
838 * redirect.
839 */
840 if (peer->rate_tokens == 0 ||
841 time_after(jiffies,
842 (peer->rate_last +
843 (ip_rt_redirect_load << peer->rate_tokens)))) {
844 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
845 peer->rate_last = jiffies;
846 ++peer->rate_tokens;
847 #ifdef CONFIG_IP_ROUTE_VERBOSE
848 if (log_martians &&
849 peer->rate_tokens == ip_rt_redirect_number)
850 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
851 &ip_hdr(skb)->saddr, inet_iif(skb),
852 &ip_hdr(skb)->daddr, &rt->rt_gateway);
853 #endif
854 }
855 out_put_peer:
856 inet_putpeer(peer);
857 }
858
859 static int ip_error(struct sk_buff *skb)
860 {
861 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
862 struct rtable *rt = skb_rtable(skb);
863 struct inet_peer *peer;
864 unsigned long now;
865 struct net *net;
866 bool send;
867 int code;
868
869 net = dev_net(rt->dst.dev);
870 if (!IN_DEV_FORWARD(in_dev)) {
871 switch (rt->dst.error) {
872 case EHOSTUNREACH:
873 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
874 break;
875
876 case ENETUNREACH:
877 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
878 break;
879 }
880 goto out;
881 }
882
883 switch (rt->dst.error) {
884 case EINVAL:
885 default:
886 goto out;
887 case EHOSTUNREACH:
888 code = ICMP_HOST_UNREACH;
889 break;
890 case ENETUNREACH:
891 code = ICMP_NET_UNREACH;
892 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
893 break;
894 case EACCES:
895 code = ICMP_PKT_FILTERED;
896 break;
897 }
898
899 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
900
901 send = true;
902 if (peer) {
903 now = jiffies;
904 peer->rate_tokens += now - peer->rate_last;
905 if (peer->rate_tokens > ip_rt_error_burst)
906 peer->rate_tokens = ip_rt_error_burst;
907 peer->rate_last = now;
908 if (peer->rate_tokens >= ip_rt_error_cost)
909 peer->rate_tokens -= ip_rt_error_cost;
910 else
911 send = false;
912 inet_putpeer(peer);
913 }
914 if (send)
915 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
916
917 out: kfree_skb(skb);
918 return 0;
919 }
920
921 static u32 __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
922 {
923 struct fib_result res;
924
925 if (mtu < ip_rt_min_pmtu)
926 mtu = ip_rt_min_pmtu;
927
928 if (fib_lookup(dev_net(rt->dst.dev), fl4, &res) == 0) {
929 struct fib_nh *nh = &FIB_RES_NH(res);
930
931 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
932 jiffies + ip_rt_mtu_expires);
933 }
934 return mtu;
935 }
936
937 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
938 struct sk_buff *skb, u32 mtu)
939 {
940 struct rtable *rt = (struct rtable *) dst;
941 struct flowi4 fl4;
942
943 ip_rt_build_flow_key(&fl4, sk, skb);
944 mtu = __ip_rt_update_pmtu(rt, &fl4, mtu);
945
946 if (!rt->rt_pmtu) {
947 dst->obsolete = DST_OBSOLETE_KILL;
948 } else {
949 rt->rt_pmtu = mtu;
950 dst_set_expires(&rt->dst, ip_rt_mtu_expires);
951 }
952 }
953
954 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
955 int oif, u32 mark, u8 protocol, int flow_flags)
956 {
957 const struct iphdr *iph = (const struct iphdr *) skb->data;
958 struct flowi4 fl4;
959 struct rtable *rt;
960
961 __build_flow_key(&fl4, NULL, iph, oif,
962 RT_TOS(iph->tos), protocol, mark, flow_flags);
963 rt = __ip_route_output_key(net, &fl4);
964 if (!IS_ERR(rt)) {
965 __ip_rt_update_pmtu(rt, &fl4, mtu);
966 ip_rt_put(rt);
967 }
968 }
969 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
970
971 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
972 {
973 const struct iphdr *iph = (const struct iphdr *) skb->data;
974 struct flowi4 fl4;
975 struct rtable *rt;
976
977 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
978 rt = __ip_route_output_key(sock_net(sk), &fl4);
979 if (!IS_ERR(rt)) {
980 __ip_rt_update_pmtu(rt, &fl4, mtu);
981 ip_rt_put(rt);
982 }
983 }
984 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
985
986 void ipv4_redirect(struct sk_buff *skb, struct net *net,
987 int oif, u32 mark, u8 protocol, int flow_flags)
988 {
989 const struct iphdr *iph = (const struct iphdr *) skb->data;
990 struct flowi4 fl4;
991 struct rtable *rt;
992
993 __build_flow_key(&fl4, NULL, iph, oif,
994 RT_TOS(iph->tos), protocol, mark, flow_flags);
995 rt = __ip_route_output_key(net, &fl4);
996 if (!IS_ERR(rt)) {
997 __ip_do_redirect(rt, skb, &fl4, false);
998 ip_rt_put(rt);
999 }
1000 }
1001 EXPORT_SYMBOL_GPL(ipv4_redirect);
1002
1003 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1004 {
1005 const struct iphdr *iph = (const struct iphdr *) skb->data;
1006 struct flowi4 fl4;
1007 struct rtable *rt;
1008
1009 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1010 rt = __ip_route_output_key(sock_net(sk), &fl4);
1011 if (!IS_ERR(rt)) {
1012 __ip_do_redirect(rt, skb, &fl4, false);
1013 ip_rt_put(rt);
1014 }
1015 }
1016 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1017
1018 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1019 {
1020 struct rtable *rt = (struct rtable *) dst;
1021
1022 /* All IPV4 dsts are created with ->obsolete set to the value
1023 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1024 * into this function always.
1025 *
1026 * When a PMTU/redirect information update invalidates a
1027 * route, this is indicated by setting obsolete to
1028 * DST_OBSOLETE_KILL.
1029 */
1030 if (dst->obsolete == DST_OBSOLETE_KILL || rt_is_expired(rt))
1031 return NULL;
1032 return dst;
1033 }
1034
1035 static void ipv4_link_failure(struct sk_buff *skb)
1036 {
1037 struct rtable *rt;
1038
1039 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1040
1041 rt = skb_rtable(skb);
1042 if (rt)
1043 dst_set_expires(&rt->dst, 0);
1044 }
1045
1046 static int ip_rt_bug(struct sk_buff *skb)
1047 {
1048 pr_debug("%s: %pI4 -> %pI4, %s\n",
1049 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1050 skb->dev ? skb->dev->name : "?");
1051 kfree_skb(skb);
1052 WARN_ON(1);
1053 return 0;
1054 }
1055
1056 /*
1057 We do not cache source address of outgoing interface,
1058 because it is used only by IP RR, TS and SRR options,
1059 so that it out of fast path.
1060
1061 BTW remember: "addr" is allowed to be not aligned
1062 in IP options!
1063 */
1064
1065 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1066 {
1067 __be32 src;
1068
1069 if (rt_is_output_route(rt))
1070 src = ip_hdr(skb)->saddr;
1071 else {
1072 struct fib_result res;
1073 struct flowi4 fl4;
1074 struct iphdr *iph;
1075
1076 iph = ip_hdr(skb);
1077
1078 memset(&fl4, 0, sizeof(fl4));
1079 fl4.daddr = iph->daddr;
1080 fl4.saddr = iph->saddr;
1081 fl4.flowi4_tos = RT_TOS(iph->tos);
1082 fl4.flowi4_oif = rt->dst.dev->ifindex;
1083 fl4.flowi4_iif = skb->dev->ifindex;
1084 fl4.flowi4_mark = skb->mark;
1085
1086 rcu_read_lock();
1087 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1088 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1089 else
1090 src = inet_select_addr(rt->dst.dev,
1091 rt_nexthop(rt, iph->daddr),
1092 RT_SCOPE_UNIVERSE);
1093 rcu_read_unlock();
1094 }
1095 memcpy(addr, &src, 4);
1096 }
1097
1098 #ifdef CONFIG_IP_ROUTE_CLASSID
1099 static void set_class_tag(struct rtable *rt, u32 tag)
1100 {
1101 if (!(rt->dst.tclassid & 0xFFFF))
1102 rt->dst.tclassid |= tag & 0xFFFF;
1103 if (!(rt->dst.tclassid & 0xFFFF0000))
1104 rt->dst.tclassid |= tag & 0xFFFF0000;
1105 }
1106 #endif
1107
1108 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1109 {
1110 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1111
1112 if (advmss == 0) {
1113 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1114 ip_rt_min_advmss);
1115 if (advmss > 65535 - 40)
1116 advmss = 65535 - 40;
1117 }
1118 return advmss;
1119 }
1120
1121 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1122 {
1123 const struct rtable *rt = (const struct rtable *) dst;
1124 unsigned int mtu = rt->rt_pmtu;
1125
1126 if (mtu && time_after_eq(jiffies, rt->dst.expires))
1127 mtu = 0;
1128
1129 if (!mtu)
1130 mtu = dst_metric_raw(dst, RTAX_MTU);
1131
1132 if (mtu && rt_is_output_route(rt))
1133 return mtu;
1134
1135 mtu = dst->dev->mtu;
1136
1137 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1138 if (rt->rt_gateway && mtu > 576)
1139 mtu = 576;
1140 }
1141
1142 if (mtu > IP_MAX_MTU)
1143 mtu = IP_MAX_MTU;
1144
1145 return mtu;
1146 }
1147
1148 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1149 {
1150 struct fnhe_hash_bucket *hash = nh->nh_exceptions;
1151 struct fib_nh_exception *fnhe;
1152 u32 hval;
1153
1154 if (!hash)
1155 return NULL;
1156
1157 hval = fnhe_hashfun(daddr);
1158
1159 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1160 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1161 if (fnhe->fnhe_daddr == daddr)
1162 return fnhe;
1163 }
1164 return NULL;
1165 }
1166
1167 static void rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1168 __be32 daddr)
1169 {
1170 __be32 fnhe_daddr, gw;
1171 unsigned long expires;
1172 unsigned int seq;
1173 u32 pmtu;
1174
1175 restart:
1176 seq = read_seqbegin(&fnhe_seqlock);
1177 fnhe_daddr = fnhe->fnhe_daddr;
1178 gw = fnhe->fnhe_gw;
1179 pmtu = fnhe->fnhe_pmtu;
1180 expires = fnhe->fnhe_expires;
1181 if (read_seqretry(&fnhe_seqlock, seq))
1182 goto restart;
1183
1184 if (daddr != fnhe_daddr)
1185 return;
1186
1187 if (pmtu) {
1188 unsigned long diff = expires - jiffies;
1189
1190 if (time_before(jiffies, expires)) {
1191 rt->rt_pmtu = pmtu;
1192 dst_set_expires(&rt->dst, diff);
1193 }
1194 }
1195 if (gw) {
1196 rt->rt_flags |= RTCF_REDIRECTED;
1197 rt->rt_gateway = gw;
1198 }
1199 fnhe->fnhe_stamp = jiffies;
1200 }
1201
1202 static inline void rt_free(struct rtable *rt)
1203 {
1204 call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
1205 }
1206
1207 static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1208 {
1209 struct rtable *orig, *prev, **p = &nh->nh_rth_output;
1210
1211 if (rt_is_input_route(rt))
1212 p = &nh->nh_rth_input;
1213
1214 orig = *p;
1215
1216 prev = cmpxchg(p, orig, rt);
1217 if (prev == orig) {
1218 if (orig)
1219 rt_free(orig);
1220 } else {
1221 /* Routes we intend to cache in the FIB nexthop have
1222 * the DST_NOCACHE bit clear. However, if we are
1223 * unsuccessful at storing this route into the cache
1224 * we really need to set it.
1225 */
1226 rt->dst.flags |= DST_NOCACHE;
1227 }
1228 }
1229
1230 static bool rt_cache_valid(const struct rtable *rt)
1231 {
1232 return rt &&
1233 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1234 !rt_is_expired(rt);
1235 }
1236
1237 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1238 const struct fib_result *res,
1239 struct fib_nh_exception *fnhe,
1240 struct fib_info *fi, u16 type, u32 itag)
1241 {
1242 if (fi) {
1243 struct fib_nh *nh = &FIB_RES_NH(*res);
1244
1245 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK)
1246 rt->rt_gateway = nh->nh_gw;
1247 if (unlikely(fnhe))
1248 rt_bind_exception(rt, fnhe, daddr);
1249 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1250 #ifdef CONFIG_IP_ROUTE_CLASSID
1251 rt->dst.tclassid = nh->nh_tclassid;
1252 #endif
1253 if (!(rt->dst.flags & DST_NOCACHE))
1254 rt_cache_route(nh, rt);
1255 }
1256
1257 #ifdef CONFIG_IP_ROUTE_CLASSID
1258 #ifdef CONFIG_IP_MULTIPLE_TABLES
1259 set_class_tag(rt, res->tclassid);
1260 #endif
1261 set_class_tag(rt, itag);
1262 #endif
1263 }
1264
1265 static struct rtable *rt_dst_alloc(struct net_device *dev,
1266 bool nopolicy, bool noxfrm, bool will_cache)
1267 {
1268 return dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1269 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1270 (nopolicy ? DST_NOPOLICY : 0) |
1271 (noxfrm ? DST_NOXFRM : 0));
1272 }
1273
1274 /* called in rcu_read_lock() section */
1275 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1276 u8 tos, struct net_device *dev, int our)
1277 {
1278 struct rtable *rth;
1279 struct in_device *in_dev = __in_dev_get_rcu(dev);
1280 u32 itag = 0;
1281 int err;
1282
1283 /* Primary sanity checks. */
1284
1285 if (in_dev == NULL)
1286 return -EINVAL;
1287
1288 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1289 skb->protocol != htons(ETH_P_IP))
1290 goto e_inval;
1291
1292 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1293 if (ipv4_is_loopback(saddr))
1294 goto e_inval;
1295
1296 if (ipv4_is_zeronet(saddr)) {
1297 if (!ipv4_is_local_multicast(daddr))
1298 goto e_inval;
1299 } else {
1300 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1301 in_dev, &itag);
1302 if (err < 0)
1303 goto e_err;
1304 }
1305 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1306 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1307 if (!rth)
1308 goto e_nobufs;
1309
1310 #ifdef CONFIG_IP_ROUTE_CLASSID
1311 rth->dst.tclassid = itag;
1312 #endif
1313 rth->dst.output = ip_rt_bug;
1314
1315 rth->rt_genid = rt_genid(dev_net(dev));
1316 rth->rt_flags = RTCF_MULTICAST;
1317 rth->rt_type = RTN_MULTICAST;
1318 rth->rt_is_input= 1;
1319 rth->rt_iif = 0;
1320 rth->rt_pmtu = 0;
1321 rth->rt_gateway = 0;
1322 if (our) {
1323 rth->dst.input= ip_local_deliver;
1324 rth->rt_flags |= RTCF_LOCAL;
1325 }
1326
1327 #ifdef CONFIG_IP_MROUTE
1328 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1329 rth->dst.input = ip_mr_input;
1330 #endif
1331 RT_CACHE_STAT_INC(in_slow_mc);
1332
1333 skb_dst_set(skb, &rth->dst);
1334 return 0;
1335
1336 e_nobufs:
1337 return -ENOBUFS;
1338 e_inval:
1339 return -EINVAL;
1340 e_err:
1341 return err;
1342 }
1343
1344
1345 static void ip_handle_martian_source(struct net_device *dev,
1346 struct in_device *in_dev,
1347 struct sk_buff *skb,
1348 __be32 daddr,
1349 __be32 saddr)
1350 {
1351 RT_CACHE_STAT_INC(in_martian_src);
1352 #ifdef CONFIG_IP_ROUTE_VERBOSE
1353 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1354 /*
1355 * RFC1812 recommendation, if source is martian,
1356 * the only hint is MAC header.
1357 */
1358 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1359 &daddr, &saddr, dev->name);
1360 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1361 print_hex_dump(KERN_WARNING, "ll header: ",
1362 DUMP_PREFIX_OFFSET, 16, 1,
1363 skb_mac_header(skb),
1364 dev->hard_header_len, true);
1365 }
1366 }
1367 #endif
1368 }
1369
1370 /* called in rcu_read_lock() section */
1371 static int __mkroute_input(struct sk_buff *skb,
1372 const struct fib_result *res,
1373 struct in_device *in_dev,
1374 __be32 daddr, __be32 saddr, u32 tos)
1375 {
1376 struct rtable *rth;
1377 int err;
1378 struct in_device *out_dev;
1379 unsigned int flags = 0;
1380 bool do_cache;
1381 u32 itag;
1382
1383 /* get a working reference to the output device */
1384 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1385 if (out_dev == NULL) {
1386 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1387 return -EINVAL;
1388 }
1389
1390
1391 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1392 in_dev->dev, in_dev, &itag);
1393 if (err < 0) {
1394 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1395 saddr);
1396
1397 goto cleanup;
1398 }
1399
1400 if (out_dev == in_dev && err &&
1401 (IN_DEV_SHARED_MEDIA(out_dev) ||
1402 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1403 flags |= RTCF_DOREDIRECT;
1404
1405 if (skb->protocol != htons(ETH_P_IP)) {
1406 /* Not IP (i.e. ARP). Do not create route, if it is
1407 * invalid for proxy arp. DNAT routes are always valid.
1408 *
1409 * Proxy arp feature have been extended to allow, ARP
1410 * replies back to the same interface, to support
1411 * Private VLAN switch technologies. See arp.c.
1412 */
1413 if (out_dev == in_dev &&
1414 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1415 err = -EINVAL;
1416 goto cleanup;
1417 }
1418 }
1419
1420 do_cache = false;
1421 if (res->fi) {
1422 if (!itag) {
1423 rth = FIB_RES_NH(*res).nh_rth_input;
1424 if (rt_cache_valid(rth)) {
1425 skb_dst_set_noref(skb, &rth->dst);
1426 goto out;
1427 }
1428 do_cache = true;
1429 }
1430 }
1431
1432 rth = rt_dst_alloc(out_dev->dev,
1433 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1434 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1435 if (!rth) {
1436 err = -ENOBUFS;
1437 goto cleanup;
1438 }
1439
1440 rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
1441 rth->rt_flags = flags;
1442 rth->rt_type = res->type;
1443 rth->rt_is_input = 1;
1444 rth->rt_iif = 0;
1445 rth->rt_pmtu = 0;
1446 rth->rt_gateway = 0;
1447
1448 rth->dst.input = ip_forward;
1449 rth->dst.output = ip_output;
1450
1451 rt_set_nexthop(rth, daddr, res, NULL, res->fi, res->type, itag);
1452 skb_dst_set(skb, &rth->dst);
1453 out:
1454 err = 0;
1455 cleanup:
1456 return err;
1457 }
1458
1459 static int ip_mkroute_input(struct sk_buff *skb,
1460 struct fib_result *res,
1461 const struct flowi4 *fl4,
1462 struct in_device *in_dev,
1463 __be32 daddr, __be32 saddr, u32 tos)
1464 {
1465 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1466 if (res->fi && res->fi->fib_nhs > 1)
1467 fib_select_multipath(res);
1468 #endif
1469
1470 /* create a routing cache entry */
1471 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1472 }
1473
1474 /*
1475 * NOTE. We drop all the packets that has local source
1476 * addresses, because every properly looped back packet
1477 * must have correct destination already attached by output routine.
1478 *
1479 * Such approach solves two big problems:
1480 * 1. Not simplex devices are handled properly.
1481 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1482 * called with rcu_read_lock()
1483 */
1484
1485 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1486 u8 tos, struct net_device *dev)
1487 {
1488 struct fib_result res;
1489 struct in_device *in_dev = __in_dev_get_rcu(dev);
1490 struct flowi4 fl4;
1491 unsigned int flags = 0;
1492 u32 itag = 0;
1493 struct rtable *rth;
1494 int err = -EINVAL;
1495 struct net *net = dev_net(dev);
1496 bool do_cache;
1497
1498 /* IP on this device is disabled. */
1499
1500 if (!in_dev)
1501 goto out;
1502
1503 /* Check for the most weird martians, which can be not detected
1504 by fib_lookup.
1505 */
1506
1507 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1508 goto martian_source;
1509
1510 res.fi = NULL;
1511 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1512 goto brd_input;
1513
1514 /* Accept zero addresses only to limited broadcast;
1515 * I even do not know to fix it or not. Waiting for complains :-)
1516 */
1517 if (ipv4_is_zeronet(saddr))
1518 goto martian_source;
1519
1520 if (ipv4_is_zeronet(daddr))
1521 goto martian_destination;
1522
1523 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
1524 if (ipv4_is_loopback(daddr))
1525 goto martian_destination;
1526
1527 if (ipv4_is_loopback(saddr))
1528 goto martian_source;
1529 }
1530
1531 /*
1532 * Now we are ready to route packet.
1533 */
1534 fl4.flowi4_oif = 0;
1535 fl4.flowi4_iif = dev->ifindex;
1536 fl4.flowi4_mark = skb->mark;
1537 fl4.flowi4_tos = tos;
1538 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1539 fl4.daddr = daddr;
1540 fl4.saddr = saddr;
1541 err = fib_lookup(net, &fl4, &res);
1542 if (err != 0)
1543 goto no_route;
1544
1545 RT_CACHE_STAT_INC(in_slow_tot);
1546
1547 if (res.type == RTN_BROADCAST)
1548 goto brd_input;
1549
1550 if (res.type == RTN_LOCAL) {
1551 err = fib_validate_source(skb, saddr, daddr, tos,
1552 net->loopback_dev->ifindex,
1553 dev, in_dev, &itag);
1554 if (err < 0)
1555 goto martian_source_keep_err;
1556 goto local_input;
1557 }
1558
1559 if (!IN_DEV_FORWARD(in_dev))
1560 goto no_route;
1561 if (res.type != RTN_UNICAST)
1562 goto martian_destination;
1563
1564 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1565 out: return err;
1566
1567 brd_input:
1568 if (skb->protocol != htons(ETH_P_IP))
1569 goto e_inval;
1570
1571 if (!ipv4_is_zeronet(saddr)) {
1572 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1573 in_dev, &itag);
1574 if (err < 0)
1575 goto martian_source_keep_err;
1576 }
1577 flags |= RTCF_BROADCAST;
1578 res.type = RTN_BROADCAST;
1579 RT_CACHE_STAT_INC(in_brd);
1580
1581 local_input:
1582 do_cache = false;
1583 if (res.fi) {
1584 if (!itag) {
1585 rth = FIB_RES_NH(res).nh_rth_input;
1586 if (rt_cache_valid(rth)) {
1587 skb_dst_set_noref(skb, &rth->dst);
1588 err = 0;
1589 goto out;
1590 }
1591 do_cache = true;
1592 }
1593 }
1594
1595 rth = rt_dst_alloc(net->loopback_dev,
1596 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1597 if (!rth)
1598 goto e_nobufs;
1599
1600 rth->dst.input= ip_local_deliver;
1601 rth->dst.output= ip_rt_bug;
1602 #ifdef CONFIG_IP_ROUTE_CLASSID
1603 rth->dst.tclassid = itag;
1604 #endif
1605
1606 rth->rt_genid = rt_genid(net);
1607 rth->rt_flags = flags|RTCF_LOCAL;
1608 rth->rt_type = res.type;
1609 rth->rt_is_input = 1;
1610 rth->rt_iif = 0;
1611 rth->rt_pmtu = 0;
1612 rth->rt_gateway = 0;
1613 if (res.type == RTN_UNREACHABLE) {
1614 rth->dst.input= ip_error;
1615 rth->dst.error= -err;
1616 rth->rt_flags &= ~RTCF_LOCAL;
1617 }
1618 if (do_cache)
1619 rt_cache_route(&FIB_RES_NH(res), rth);
1620 skb_dst_set(skb, &rth->dst);
1621 err = 0;
1622 goto out;
1623
1624 no_route:
1625 RT_CACHE_STAT_INC(in_no_route);
1626 res.type = RTN_UNREACHABLE;
1627 if (err == -ESRCH)
1628 err = -ENETUNREACH;
1629 goto local_input;
1630
1631 /*
1632 * Do not cache martian addresses: they should be logged (RFC1812)
1633 */
1634 martian_destination:
1635 RT_CACHE_STAT_INC(in_martian_dst);
1636 #ifdef CONFIG_IP_ROUTE_VERBOSE
1637 if (IN_DEV_LOG_MARTIANS(in_dev))
1638 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1639 &daddr, &saddr, dev->name);
1640 #endif
1641
1642 e_inval:
1643 err = -EINVAL;
1644 goto out;
1645
1646 e_nobufs:
1647 err = -ENOBUFS;
1648 goto out;
1649
1650 martian_source:
1651 err = -EINVAL;
1652 martian_source_keep_err:
1653 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1654 goto out;
1655 }
1656
1657 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1658 u8 tos, struct net_device *dev)
1659 {
1660 int res;
1661
1662 rcu_read_lock();
1663
1664 /* Multicast recognition logic is moved from route cache to here.
1665 The problem was that too many Ethernet cards have broken/missing
1666 hardware multicast filters :-( As result the host on multicasting
1667 network acquires a lot of useless route cache entries, sort of
1668 SDR messages from all the world. Now we try to get rid of them.
1669 Really, provided software IP multicast filter is organized
1670 reasonably (at least, hashed), it does not result in a slowdown
1671 comparing with route cache reject entries.
1672 Note, that multicast routers are not affected, because
1673 route cache entry is created eventually.
1674 */
1675 if (ipv4_is_multicast(daddr)) {
1676 struct in_device *in_dev = __in_dev_get_rcu(dev);
1677
1678 if (in_dev) {
1679 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1680 ip_hdr(skb)->protocol);
1681 if (our
1682 #ifdef CONFIG_IP_MROUTE
1683 ||
1684 (!ipv4_is_local_multicast(daddr) &&
1685 IN_DEV_MFORWARD(in_dev))
1686 #endif
1687 ) {
1688 int res = ip_route_input_mc(skb, daddr, saddr,
1689 tos, dev, our);
1690 rcu_read_unlock();
1691 return res;
1692 }
1693 }
1694 rcu_read_unlock();
1695 return -EINVAL;
1696 }
1697 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1698 rcu_read_unlock();
1699 return res;
1700 }
1701 EXPORT_SYMBOL(ip_route_input_noref);
1702
1703 /* called with rcu_read_lock() */
1704 static struct rtable *__mkroute_output(const struct fib_result *res,
1705 const struct flowi4 *fl4, int orig_oif,
1706 struct net_device *dev_out,
1707 unsigned int flags)
1708 {
1709 struct fib_info *fi = res->fi;
1710 struct fib_nh_exception *fnhe;
1711 struct in_device *in_dev;
1712 u16 type = res->type;
1713 struct rtable *rth;
1714
1715 in_dev = __in_dev_get_rcu(dev_out);
1716 if (!in_dev)
1717 return ERR_PTR(-EINVAL);
1718
1719 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1720 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
1721 return ERR_PTR(-EINVAL);
1722
1723 if (ipv4_is_lbcast(fl4->daddr))
1724 type = RTN_BROADCAST;
1725 else if (ipv4_is_multicast(fl4->daddr))
1726 type = RTN_MULTICAST;
1727 else if (ipv4_is_zeronet(fl4->daddr))
1728 return ERR_PTR(-EINVAL);
1729
1730 if (dev_out->flags & IFF_LOOPBACK)
1731 flags |= RTCF_LOCAL;
1732
1733 if (type == RTN_BROADCAST) {
1734 flags |= RTCF_BROADCAST | RTCF_LOCAL;
1735 fi = NULL;
1736 } else if (type == RTN_MULTICAST) {
1737 flags |= RTCF_MULTICAST | RTCF_LOCAL;
1738 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
1739 fl4->flowi4_proto))
1740 flags &= ~RTCF_LOCAL;
1741 /* If multicast route do not exist use
1742 * default one, but do not gateway in this case.
1743 * Yes, it is hack.
1744 */
1745 if (fi && res->prefixlen < 4)
1746 fi = NULL;
1747 }
1748
1749 fnhe = NULL;
1750 if (fi) {
1751 fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);
1752 if (!fnhe) {
1753 rth = FIB_RES_NH(*res).nh_rth_output;
1754 if (rt_cache_valid(rth)) {
1755 dst_hold(&rth->dst);
1756 return rth;
1757 }
1758 }
1759 }
1760 rth = rt_dst_alloc(dev_out,
1761 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1762 IN_DEV_CONF_GET(in_dev, NOXFRM),
1763 fi && !fnhe);
1764 if (!rth)
1765 return ERR_PTR(-ENOBUFS);
1766
1767 rth->dst.output = ip_output;
1768
1769 rth->rt_genid = rt_genid(dev_net(dev_out));
1770 rth->rt_flags = flags;
1771 rth->rt_type = type;
1772 rth->rt_is_input = 0;
1773 rth->rt_iif = orig_oif ? : 0;
1774 rth->rt_pmtu = 0;
1775 rth->rt_gateway = 0;
1776
1777 RT_CACHE_STAT_INC(out_slow_tot);
1778
1779 if (flags & RTCF_LOCAL)
1780 rth->dst.input = ip_local_deliver;
1781 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1782 if (flags & RTCF_LOCAL &&
1783 !(dev_out->flags & IFF_LOOPBACK)) {
1784 rth->dst.output = ip_mc_output;
1785 RT_CACHE_STAT_INC(out_slow_mc);
1786 }
1787 #ifdef CONFIG_IP_MROUTE
1788 if (type == RTN_MULTICAST) {
1789 if (IN_DEV_MFORWARD(in_dev) &&
1790 !ipv4_is_local_multicast(fl4->daddr)) {
1791 rth->dst.input = ip_mr_input;
1792 rth->dst.output = ip_mc_output;
1793 }
1794 }
1795 #endif
1796 }
1797
1798 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
1799
1800 return rth;
1801 }
1802
1803 /*
1804 * Major route resolver routine.
1805 */
1806
1807 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
1808 {
1809 struct net_device *dev_out = NULL;
1810 __u8 tos = RT_FL_TOS(fl4);
1811 unsigned int flags = 0;
1812 struct fib_result res;
1813 struct rtable *rth;
1814 int orig_oif;
1815
1816 res.tclassid = 0;
1817 res.fi = NULL;
1818 res.table = NULL;
1819
1820 orig_oif = fl4->flowi4_oif;
1821
1822 fl4->flowi4_iif = net->loopback_dev->ifindex;
1823 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
1824 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
1825 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
1826
1827 rcu_read_lock();
1828 if (fl4->saddr) {
1829 rth = ERR_PTR(-EINVAL);
1830 if (ipv4_is_multicast(fl4->saddr) ||
1831 ipv4_is_lbcast(fl4->saddr) ||
1832 ipv4_is_zeronet(fl4->saddr))
1833 goto out;
1834
1835 /* I removed check for oif == dev_out->oif here.
1836 It was wrong for two reasons:
1837 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
1838 is assigned to multiple interfaces.
1839 2. Moreover, we are allowed to send packets with saddr
1840 of another iface. --ANK
1841 */
1842
1843 if (fl4->flowi4_oif == 0 &&
1844 (ipv4_is_multicast(fl4->daddr) ||
1845 ipv4_is_lbcast(fl4->daddr))) {
1846 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1847 dev_out = __ip_dev_find(net, fl4->saddr, false);
1848 if (dev_out == NULL)
1849 goto out;
1850
1851 /* Special hack: user can direct multicasts
1852 and limited broadcast via necessary interface
1853 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
1854 This hack is not just for fun, it allows
1855 vic,vat and friends to work.
1856 They bind socket to loopback, set ttl to zero
1857 and expect that it will work.
1858 From the viewpoint of routing cache they are broken,
1859 because we are not allowed to build multicast path
1860 with loopback source addr (look, routing cache
1861 cannot know, that ttl is zero, so that packet
1862 will not leave this host and route is valid).
1863 Luckily, this hack is good workaround.
1864 */
1865
1866 fl4->flowi4_oif = dev_out->ifindex;
1867 goto make_route;
1868 }
1869
1870 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
1871 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1872 if (!__ip_dev_find(net, fl4->saddr, false))
1873 goto out;
1874 }
1875 }
1876
1877
1878 if (fl4->flowi4_oif) {
1879 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
1880 rth = ERR_PTR(-ENODEV);
1881 if (dev_out == NULL)
1882 goto out;
1883
1884 /* RACE: Check return value of inet_select_addr instead. */
1885 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
1886 rth = ERR_PTR(-ENETUNREACH);
1887 goto out;
1888 }
1889 if (ipv4_is_local_multicast(fl4->daddr) ||
1890 ipv4_is_lbcast(fl4->daddr)) {
1891 if (!fl4->saddr)
1892 fl4->saddr = inet_select_addr(dev_out, 0,
1893 RT_SCOPE_LINK);
1894 goto make_route;
1895 }
1896 if (fl4->saddr) {
1897 if (ipv4_is_multicast(fl4->daddr))
1898 fl4->saddr = inet_select_addr(dev_out, 0,
1899 fl4->flowi4_scope);
1900 else if (!fl4->daddr)
1901 fl4->saddr = inet_select_addr(dev_out, 0,
1902 RT_SCOPE_HOST);
1903 }
1904 }
1905
1906 if (!fl4->daddr) {
1907 fl4->daddr = fl4->saddr;
1908 if (!fl4->daddr)
1909 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
1910 dev_out = net->loopback_dev;
1911 fl4->flowi4_oif = net->loopback_dev->ifindex;
1912 res.type = RTN_LOCAL;
1913 flags |= RTCF_LOCAL;
1914 goto make_route;
1915 }
1916
1917 if (fib_lookup(net, fl4, &res)) {
1918 res.fi = NULL;
1919 res.table = NULL;
1920 if (fl4->flowi4_oif) {
1921 /* Apparently, routing tables are wrong. Assume,
1922 that the destination is on link.
1923
1924 WHY? DW.
1925 Because we are allowed to send to iface
1926 even if it has NO routes and NO assigned
1927 addresses. When oif is specified, routing
1928 tables are looked up with only one purpose:
1929 to catch if destination is gatewayed, rather than
1930 direct. Moreover, if MSG_DONTROUTE is set,
1931 we send packet, ignoring both routing tables
1932 and ifaddr state. --ANK
1933
1934
1935 We could make it even if oif is unknown,
1936 likely IPv6, but we do not.
1937 */
1938
1939 if (fl4->saddr == 0)
1940 fl4->saddr = inet_select_addr(dev_out, 0,
1941 RT_SCOPE_LINK);
1942 res.type = RTN_UNICAST;
1943 goto make_route;
1944 }
1945 rth = ERR_PTR(-ENETUNREACH);
1946 goto out;
1947 }
1948
1949 if (res.type == RTN_LOCAL) {
1950 if (!fl4->saddr) {
1951 if (res.fi->fib_prefsrc)
1952 fl4->saddr = res.fi->fib_prefsrc;
1953 else
1954 fl4->saddr = fl4->daddr;
1955 }
1956 dev_out = net->loopback_dev;
1957 fl4->flowi4_oif = dev_out->ifindex;
1958 res.fi = NULL;
1959 flags |= RTCF_LOCAL;
1960 goto make_route;
1961 }
1962
1963 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1964 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
1965 fib_select_multipath(&res);
1966 else
1967 #endif
1968 if (!res.prefixlen &&
1969 res.table->tb_num_default > 1 &&
1970 res.type == RTN_UNICAST && !fl4->flowi4_oif)
1971 fib_select_default(&res);
1972
1973 if (!fl4->saddr)
1974 fl4->saddr = FIB_RES_PREFSRC(net, res);
1975
1976 dev_out = FIB_RES_DEV(res);
1977 fl4->flowi4_oif = dev_out->ifindex;
1978
1979
1980 make_route:
1981 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
1982
1983 out:
1984 rcu_read_unlock();
1985 return rth;
1986 }
1987 EXPORT_SYMBOL_GPL(__ip_route_output_key);
1988
1989 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
1990 {
1991 return NULL;
1992 }
1993
1994 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
1995 {
1996 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
1997
1998 return mtu ? : dst->dev->mtu;
1999 }
2000
2001 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2002 struct sk_buff *skb, u32 mtu)
2003 {
2004 }
2005
2006 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2007 struct sk_buff *skb)
2008 {
2009 }
2010
2011 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2012 unsigned long old)
2013 {
2014 return NULL;
2015 }
2016
2017 static struct dst_ops ipv4_dst_blackhole_ops = {
2018 .family = AF_INET,
2019 .protocol = cpu_to_be16(ETH_P_IP),
2020 .check = ipv4_blackhole_dst_check,
2021 .mtu = ipv4_blackhole_mtu,
2022 .default_advmss = ipv4_default_advmss,
2023 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2024 .redirect = ipv4_rt_blackhole_redirect,
2025 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2026 .neigh_lookup = ipv4_neigh_lookup,
2027 };
2028
2029 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2030 {
2031 struct rtable *ort = (struct rtable *) dst_orig;
2032 struct rtable *rt;
2033
2034 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2035 if (rt) {
2036 struct dst_entry *new = &rt->dst;
2037
2038 new->__use = 1;
2039 new->input = dst_discard;
2040 new->output = dst_discard;
2041
2042 new->dev = ort->dst.dev;
2043 if (new->dev)
2044 dev_hold(new->dev);
2045
2046 rt->rt_is_input = ort->rt_is_input;
2047 rt->rt_iif = ort->rt_iif;
2048 rt->rt_pmtu = ort->rt_pmtu;
2049
2050 rt->rt_genid = rt_genid(net);
2051 rt->rt_flags = ort->rt_flags;
2052 rt->rt_type = ort->rt_type;
2053 rt->rt_gateway = ort->rt_gateway;
2054
2055 dst_free(new);
2056 }
2057
2058 dst_release(dst_orig);
2059
2060 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2061 }
2062
2063 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2064 struct sock *sk)
2065 {
2066 struct rtable *rt = __ip_route_output_key(net, flp4);
2067
2068 if (IS_ERR(rt))
2069 return rt;
2070
2071 if (flp4->flowi4_proto)
2072 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2073 flowi4_to_flowi(flp4),
2074 sk, 0);
2075
2076 return rt;
2077 }
2078 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2079
2080 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2081 struct flowi4 *fl4, struct sk_buff *skb, u32 pid,
2082 u32 seq, int event, int nowait, unsigned int flags)
2083 {
2084 struct rtable *rt = skb_rtable(skb);
2085 struct rtmsg *r;
2086 struct nlmsghdr *nlh;
2087 unsigned long expires = 0;
2088 u32 error;
2089 u32 metrics[RTAX_MAX];
2090
2091 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2092 if (nlh == NULL)
2093 return -EMSGSIZE;
2094
2095 r = nlmsg_data(nlh);
2096 r->rtm_family = AF_INET;
2097 r->rtm_dst_len = 32;
2098 r->rtm_src_len = 0;
2099 r->rtm_tos = fl4->flowi4_tos;
2100 r->rtm_table = RT_TABLE_MAIN;
2101 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2102 goto nla_put_failure;
2103 r->rtm_type = rt->rt_type;
2104 r->rtm_scope = RT_SCOPE_UNIVERSE;
2105 r->rtm_protocol = RTPROT_UNSPEC;
2106 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2107 if (rt->rt_flags & RTCF_NOTIFY)
2108 r->rtm_flags |= RTM_F_NOTIFY;
2109
2110 if (nla_put_be32(skb, RTA_DST, dst))
2111 goto nla_put_failure;
2112 if (src) {
2113 r->rtm_src_len = 32;
2114 if (nla_put_be32(skb, RTA_SRC, src))
2115 goto nla_put_failure;
2116 }
2117 if (rt->dst.dev &&
2118 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2119 goto nla_put_failure;
2120 #ifdef CONFIG_IP_ROUTE_CLASSID
2121 if (rt->dst.tclassid &&
2122 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2123 goto nla_put_failure;
2124 #endif
2125 if (!rt_is_input_route(rt) &&
2126 fl4->saddr != src) {
2127 if (nla_put_be32(skb, RTA_PREFSRC, fl4->saddr))
2128 goto nla_put_failure;
2129 }
2130 if (rt->rt_gateway &&
2131 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2132 goto nla_put_failure;
2133
2134 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2135 if (rt->rt_pmtu)
2136 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2137 if (rtnetlink_put_metrics(skb, metrics) < 0)
2138 goto nla_put_failure;
2139
2140 if (fl4->flowi4_mark &&
2141 nla_put_be32(skb, RTA_MARK, fl4->flowi4_mark))
2142 goto nla_put_failure;
2143
2144 error = rt->dst.error;
2145 expires = rt->dst.expires;
2146 if (expires) {
2147 if (time_before(jiffies, expires))
2148 expires -= jiffies;
2149 else
2150 expires = 0;
2151 }
2152
2153 if (rt_is_input_route(rt)) {
2154 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
2155 goto nla_put_failure;
2156 }
2157
2158 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2159 goto nla_put_failure;
2160
2161 return nlmsg_end(skb, nlh);
2162
2163 nla_put_failure:
2164 nlmsg_cancel(skb, nlh);
2165 return -EMSGSIZE;
2166 }
2167
2168 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
2169 {
2170 struct net *net = sock_net(in_skb->sk);
2171 struct rtmsg *rtm;
2172 struct nlattr *tb[RTA_MAX+1];
2173 struct rtable *rt = NULL;
2174 struct flowi4 fl4;
2175 __be32 dst = 0;
2176 __be32 src = 0;
2177 u32 iif;
2178 int err;
2179 int mark;
2180 struct sk_buff *skb;
2181
2182 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2183 if (err < 0)
2184 goto errout;
2185
2186 rtm = nlmsg_data(nlh);
2187
2188 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2189 if (skb == NULL) {
2190 err = -ENOBUFS;
2191 goto errout;
2192 }
2193
2194 /* Reserve room for dummy headers, this skb can pass
2195 through good chunk of routing engine.
2196 */
2197 skb_reset_mac_header(skb);
2198 skb_reset_network_header(skb);
2199
2200 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2201 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2202 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2203
2204 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2205 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2206 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2207 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2208
2209 memset(&fl4, 0, sizeof(fl4));
2210 fl4.daddr = dst;
2211 fl4.saddr = src;
2212 fl4.flowi4_tos = rtm->rtm_tos;
2213 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2214 fl4.flowi4_mark = mark;
2215
2216 if (iif) {
2217 struct net_device *dev;
2218
2219 dev = __dev_get_by_index(net, iif);
2220 if (dev == NULL) {
2221 err = -ENODEV;
2222 goto errout_free;
2223 }
2224
2225 skb->protocol = htons(ETH_P_IP);
2226 skb->dev = dev;
2227 skb->mark = mark;
2228 local_bh_disable();
2229 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2230 local_bh_enable();
2231
2232 rt = skb_rtable(skb);
2233 if (err == 0 && rt->dst.error)
2234 err = -rt->dst.error;
2235 } else {
2236 rt = ip_route_output_key(net, &fl4);
2237
2238 err = 0;
2239 if (IS_ERR(rt))
2240 err = PTR_ERR(rt);
2241 }
2242
2243 if (err)
2244 goto errout_free;
2245
2246 skb_dst_set(skb, &rt->dst);
2247 if (rtm->rtm_flags & RTM_F_NOTIFY)
2248 rt->rt_flags |= RTCF_NOTIFY;
2249
2250 err = rt_fill_info(net, dst, src, &fl4, skb,
2251 NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2252 RTM_NEWROUTE, 0, 0);
2253 if (err <= 0)
2254 goto errout_free;
2255
2256 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2257 errout:
2258 return err;
2259
2260 errout_free:
2261 kfree_skb(skb);
2262 goto errout;
2263 }
2264
2265 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
2266 {
2267 return skb->len;
2268 }
2269
2270 void ip_rt_multicast_event(struct in_device *in_dev)
2271 {
2272 rt_cache_flush(dev_net(in_dev->dev), 0);
2273 }
2274
2275 #ifdef CONFIG_SYSCTL
2276 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
2277 void __user *buffer,
2278 size_t *lenp, loff_t *ppos)
2279 {
2280 if (write) {
2281 int flush_delay;
2282 ctl_table ctl;
2283 struct net *net;
2284
2285 memcpy(&ctl, __ctl, sizeof(ctl));
2286 ctl.data = &flush_delay;
2287 proc_dointvec(&ctl, write, buffer, lenp, ppos);
2288
2289 net = (struct net *)__ctl->extra1;
2290 rt_cache_flush(net, flush_delay);
2291 return 0;
2292 }
2293
2294 return -EINVAL;
2295 }
2296
2297 static ctl_table ipv4_route_table[] = {
2298 {
2299 .procname = "gc_thresh",
2300 .data = &ipv4_dst_ops.gc_thresh,
2301 .maxlen = sizeof(int),
2302 .mode = 0644,
2303 .proc_handler = proc_dointvec,
2304 },
2305 {
2306 .procname = "max_size",
2307 .data = &ip_rt_max_size,
2308 .maxlen = sizeof(int),
2309 .mode = 0644,
2310 .proc_handler = proc_dointvec,
2311 },
2312 {
2313 /* Deprecated. Use gc_min_interval_ms */
2314
2315 .procname = "gc_min_interval",
2316 .data = &ip_rt_gc_min_interval,
2317 .maxlen = sizeof(int),
2318 .mode = 0644,
2319 .proc_handler = proc_dointvec_jiffies,
2320 },
2321 {
2322 .procname = "gc_min_interval_ms",
2323 .data = &ip_rt_gc_min_interval,
2324 .maxlen = sizeof(int),
2325 .mode = 0644,
2326 .proc_handler = proc_dointvec_ms_jiffies,
2327 },
2328 {
2329 .procname = "gc_timeout",
2330 .data = &ip_rt_gc_timeout,
2331 .maxlen = sizeof(int),
2332 .mode = 0644,
2333 .proc_handler = proc_dointvec_jiffies,
2334 },
2335 {
2336 .procname = "gc_interval",
2337 .data = &ip_rt_gc_interval,
2338 .maxlen = sizeof(int),
2339 .mode = 0644,
2340 .proc_handler = proc_dointvec_jiffies,
2341 },
2342 {
2343 .procname = "redirect_load",
2344 .data = &ip_rt_redirect_load,
2345 .maxlen = sizeof(int),
2346 .mode = 0644,
2347 .proc_handler = proc_dointvec,
2348 },
2349 {
2350 .procname = "redirect_number",
2351 .data = &ip_rt_redirect_number,
2352 .maxlen = sizeof(int),
2353 .mode = 0644,
2354 .proc_handler = proc_dointvec,
2355 },
2356 {
2357 .procname = "redirect_silence",
2358 .data = &ip_rt_redirect_silence,
2359 .maxlen = sizeof(int),
2360 .mode = 0644,
2361 .proc_handler = proc_dointvec,
2362 },
2363 {
2364 .procname = "error_cost",
2365 .data = &ip_rt_error_cost,
2366 .maxlen = sizeof(int),
2367 .mode = 0644,
2368 .proc_handler = proc_dointvec,
2369 },
2370 {
2371 .procname = "error_burst",
2372 .data = &ip_rt_error_burst,
2373 .maxlen = sizeof(int),
2374 .mode = 0644,
2375 .proc_handler = proc_dointvec,
2376 },
2377 {
2378 .procname = "gc_elasticity",
2379 .data = &ip_rt_gc_elasticity,
2380 .maxlen = sizeof(int),
2381 .mode = 0644,
2382 .proc_handler = proc_dointvec,
2383 },
2384 {
2385 .procname = "mtu_expires",
2386 .data = &ip_rt_mtu_expires,
2387 .maxlen = sizeof(int),
2388 .mode = 0644,
2389 .proc_handler = proc_dointvec_jiffies,
2390 },
2391 {
2392 .procname = "min_pmtu",
2393 .data = &ip_rt_min_pmtu,
2394 .maxlen = sizeof(int),
2395 .mode = 0644,
2396 .proc_handler = proc_dointvec,
2397 },
2398 {
2399 .procname = "min_adv_mss",
2400 .data = &ip_rt_min_advmss,
2401 .maxlen = sizeof(int),
2402 .mode = 0644,
2403 .proc_handler = proc_dointvec,
2404 },
2405 { }
2406 };
2407
2408 static struct ctl_table ipv4_route_flush_table[] = {
2409 {
2410 .procname = "flush",
2411 .maxlen = sizeof(int),
2412 .mode = 0200,
2413 .proc_handler = ipv4_sysctl_rtcache_flush,
2414 },
2415 { },
2416 };
2417
2418 static __net_init int sysctl_route_net_init(struct net *net)
2419 {
2420 struct ctl_table *tbl;
2421
2422 tbl = ipv4_route_flush_table;
2423 if (!net_eq(net, &init_net)) {
2424 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2425 if (tbl == NULL)
2426 goto err_dup;
2427 }
2428 tbl[0].extra1 = net;
2429
2430 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2431 if (net->ipv4.route_hdr == NULL)
2432 goto err_reg;
2433 return 0;
2434
2435 err_reg:
2436 if (tbl != ipv4_route_flush_table)
2437 kfree(tbl);
2438 err_dup:
2439 return -ENOMEM;
2440 }
2441
2442 static __net_exit void sysctl_route_net_exit(struct net *net)
2443 {
2444 struct ctl_table *tbl;
2445
2446 tbl = net->ipv4.route_hdr->ctl_table_arg;
2447 unregister_net_sysctl_table(net->ipv4.route_hdr);
2448 BUG_ON(tbl == ipv4_route_flush_table);
2449 kfree(tbl);
2450 }
2451
2452 static __net_initdata struct pernet_operations sysctl_route_ops = {
2453 .init = sysctl_route_net_init,
2454 .exit = sysctl_route_net_exit,
2455 };
2456 #endif
2457
2458 static __net_init int rt_genid_init(struct net *net)
2459 {
2460 get_random_bytes(&net->ipv4.rt_genid,
2461 sizeof(net->ipv4.rt_genid));
2462 get_random_bytes(&net->ipv4.dev_addr_genid,
2463 sizeof(net->ipv4.dev_addr_genid));
2464 return 0;
2465 }
2466
2467 static __net_initdata struct pernet_operations rt_genid_ops = {
2468 .init = rt_genid_init,
2469 };
2470
2471 static int __net_init ipv4_inetpeer_init(struct net *net)
2472 {
2473 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2474
2475 if (!bp)
2476 return -ENOMEM;
2477 inet_peer_base_init(bp);
2478 net->ipv4.peers = bp;
2479 return 0;
2480 }
2481
2482 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2483 {
2484 struct inet_peer_base *bp = net->ipv4.peers;
2485
2486 net->ipv4.peers = NULL;
2487 inetpeer_invalidate_tree(bp);
2488 kfree(bp);
2489 }
2490
2491 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2492 .init = ipv4_inetpeer_init,
2493 .exit = ipv4_inetpeer_exit,
2494 };
2495
2496 #ifdef CONFIG_IP_ROUTE_CLASSID
2497 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2498 #endif /* CONFIG_IP_ROUTE_CLASSID */
2499
2500 int __init ip_rt_init(void)
2501 {
2502 int rc = 0;
2503
2504 #ifdef CONFIG_IP_ROUTE_CLASSID
2505 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2506 if (!ip_rt_acct)
2507 panic("IP: failed to allocate ip_rt_acct\n");
2508 #endif
2509
2510 ipv4_dst_ops.kmem_cachep =
2511 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2512 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2513
2514 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2515
2516 if (dst_entries_init(&ipv4_dst_ops) < 0)
2517 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2518
2519 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2520 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2521
2522 ipv4_dst_ops.gc_thresh = ~0;
2523 ip_rt_max_size = INT_MAX;
2524
2525 devinet_init();
2526 ip_fib_init();
2527
2528 if (ip_rt_proc_init())
2529 pr_err("Unable to create route proc files\n");
2530 #ifdef CONFIG_XFRM
2531 xfrm_init();
2532 xfrm4_init(ip_rt_max_size);
2533 #endif
2534 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2535
2536 #ifdef CONFIG_SYSCTL
2537 register_pernet_subsys(&sysctl_route_ops);
2538 #endif
2539 register_pernet_subsys(&rt_genid_ops);
2540 register_pernet_subsys(&ipv4_inetpeer_ops);
2541 return rc;
2542 }
2543
2544 #ifdef CONFIG_SYSCTL
2545 /*
2546 * We really need to sanitize the damn ipv4 init order, then all
2547 * this nonsense will go away.
2548 */
2549 void __init ip_static_sysctl_init(void)
2550 {
2551 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2552 }
2553 #endif
Linus' kernel tree