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Merge tag 'remoteproc-for-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad...
[deliverable/linux.git] / net / ipv4 / route.c
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 int rt_is_expired(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_release_rcu(struct rcu_head *head)
1203 {
1204 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
1205 dst_release(dst);
1206 }
1207
1208 static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1209 {
1210 struct rtable *orig, *prev, **p = &nh->nh_rth_output;
1211
1212 if (rt_is_input_route(rt))
1213 p = &nh->nh_rth_input;
1214
1215 orig = *p;
1216
1217 prev = cmpxchg(p, orig, rt);
1218 if (prev == orig) {
1219 dst_clone(&rt->dst);
1220 if (orig)
1221 call_rcu_bh(&orig->dst.rcu_head, rt_release_rcu);
1222 }
1223 }
1224
1225 static bool rt_cache_valid(struct rtable *rt)
1226 {
1227 return (rt && rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK);
1228 }
1229
1230 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1231 const struct fib_result *res,
1232 struct fib_nh_exception *fnhe,
1233 struct fib_info *fi, u16 type, u32 itag)
1234 {
1235 if (fi) {
1236 struct fib_nh *nh = &FIB_RES_NH(*res);
1237
1238 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK)
1239 rt->rt_gateway = nh->nh_gw;
1240 if (unlikely(fnhe))
1241 rt_bind_exception(rt, fnhe, daddr);
1242 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1243 #ifdef CONFIG_IP_ROUTE_CLASSID
1244 rt->dst.tclassid = nh->nh_tclassid;
1245 #endif
1246 if (!(rt->dst.flags & DST_HOST))
1247 rt_cache_route(nh, rt);
1248 }
1249
1250 #ifdef CONFIG_IP_ROUTE_CLASSID
1251 #ifdef CONFIG_IP_MULTIPLE_TABLES
1252 set_class_tag(rt, res->tclassid);
1253 #endif
1254 set_class_tag(rt, itag);
1255 #endif
1256 }
1257
1258 static struct rtable *rt_dst_alloc(struct net_device *dev,
1259 bool nopolicy, bool noxfrm, bool will_cache)
1260 {
1261 return dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1262 (will_cache ? 0 : DST_HOST) | DST_NOCACHE |
1263 (nopolicy ? DST_NOPOLICY : 0) |
1264 (noxfrm ? DST_NOXFRM : 0));
1265 }
1266
1267 /* called in rcu_read_lock() section */
1268 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1269 u8 tos, struct net_device *dev, int our)
1270 {
1271 struct rtable *rth;
1272 struct in_device *in_dev = __in_dev_get_rcu(dev);
1273 u32 itag = 0;
1274 int err;
1275
1276 /* Primary sanity checks. */
1277
1278 if (in_dev == NULL)
1279 return -EINVAL;
1280
1281 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1282 skb->protocol != htons(ETH_P_IP))
1283 goto e_inval;
1284
1285 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1286 if (ipv4_is_loopback(saddr))
1287 goto e_inval;
1288
1289 if (ipv4_is_zeronet(saddr)) {
1290 if (!ipv4_is_local_multicast(daddr))
1291 goto e_inval;
1292 } else {
1293 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1294 in_dev, &itag);
1295 if (err < 0)
1296 goto e_err;
1297 }
1298 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1299 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1300 if (!rth)
1301 goto e_nobufs;
1302
1303 #ifdef CONFIG_IP_ROUTE_CLASSID
1304 rth->dst.tclassid = itag;
1305 #endif
1306 rth->dst.output = ip_rt_bug;
1307
1308 rth->rt_genid = rt_genid(dev_net(dev));
1309 rth->rt_flags = RTCF_MULTICAST;
1310 rth->rt_type = RTN_MULTICAST;
1311 rth->rt_is_input= 1;
1312 rth->rt_iif = 0;
1313 rth->rt_pmtu = 0;
1314 rth->rt_gateway = 0;
1315 if (our) {
1316 rth->dst.input= ip_local_deliver;
1317 rth->rt_flags |= RTCF_LOCAL;
1318 }
1319
1320 #ifdef CONFIG_IP_MROUTE
1321 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1322 rth->dst.input = ip_mr_input;
1323 #endif
1324 RT_CACHE_STAT_INC(in_slow_mc);
1325
1326 skb_dst_set(skb, &rth->dst);
1327 return 0;
1328
1329 e_nobufs:
1330 return -ENOBUFS;
1331 e_inval:
1332 return -EINVAL;
1333 e_err:
1334 return err;
1335 }
1336
1337
1338 static void ip_handle_martian_source(struct net_device *dev,
1339 struct in_device *in_dev,
1340 struct sk_buff *skb,
1341 __be32 daddr,
1342 __be32 saddr)
1343 {
1344 RT_CACHE_STAT_INC(in_martian_src);
1345 #ifdef CONFIG_IP_ROUTE_VERBOSE
1346 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1347 /*
1348 * RFC1812 recommendation, if source is martian,
1349 * the only hint is MAC header.
1350 */
1351 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1352 &daddr, &saddr, dev->name);
1353 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1354 print_hex_dump(KERN_WARNING, "ll header: ",
1355 DUMP_PREFIX_OFFSET, 16, 1,
1356 skb_mac_header(skb),
1357 dev->hard_header_len, true);
1358 }
1359 }
1360 #endif
1361 }
1362
1363 /* called in rcu_read_lock() section */
1364 static int __mkroute_input(struct sk_buff *skb,
1365 const struct fib_result *res,
1366 struct in_device *in_dev,
1367 __be32 daddr, __be32 saddr, u32 tos,
1368 struct rtable **result)
1369 {
1370 struct rtable *rth;
1371 int err;
1372 struct in_device *out_dev;
1373 unsigned int flags = 0;
1374 bool do_cache;
1375 u32 itag;
1376
1377 /* get a working reference to the output device */
1378 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1379 if (out_dev == NULL) {
1380 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1381 return -EINVAL;
1382 }
1383
1384
1385 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1386 in_dev->dev, in_dev, &itag);
1387 if (err < 0) {
1388 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1389 saddr);
1390
1391 goto cleanup;
1392 }
1393
1394 if (out_dev == in_dev && err &&
1395 (IN_DEV_SHARED_MEDIA(out_dev) ||
1396 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1397 flags |= RTCF_DOREDIRECT;
1398
1399 if (skb->protocol != htons(ETH_P_IP)) {
1400 /* Not IP (i.e. ARP). Do not create route, if it is
1401 * invalid for proxy arp. DNAT routes are always valid.
1402 *
1403 * Proxy arp feature have been extended to allow, ARP
1404 * replies back to the same interface, to support
1405 * Private VLAN switch technologies. See arp.c.
1406 */
1407 if (out_dev == in_dev &&
1408 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1409 err = -EINVAL;
1410 goto cleanup;
1411 }
1412 }
1413
1414 do_cache = false;
1415 if (res->fi) {
1416 if (!itag) {
1417 rth = FIB_RES_NH(*res).nh_rth_input;
1418 if (rt_cache_valid(rth)) {
1419 dst_hold(&rth->dst);
1420 goto out;
1421 }
1422 do_cache = true;
1423 }
1424 }
1425
1426 rth = rt_dst_alloc(out_dev->dev,
1427 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1428 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1429 if (!rth) {
1430 err = -ENOBUFS;
1431 goto cleanup;
1432 }
1433
1434 rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
1435 rth->rt_flags = flags;
1436 rth->rt_type = res->type;
1437 rth->rt_is_input = 1;
1438 rth->rt_iif = 0;
1439 rth->rt_pmtu = 0;
1440 rth->rt_gateway = 0;
1441
1442 rth->dst.input = ip_forward;
1443 rth->dst.output = ip_output;
1444
1445 rt_set_nexthop(rth, daddr, res, NULL, res->fi, res->type, itag);
1446 out:
1447 *result = rth;
1448 err = 0;
1449 cleanup:
1450 return err;
1451 }
1452
1453 static int ip_mkroute_input(struct sk_buff *skb,
1454 struct fib_result *res,
1455 const struct flowi4 *fl4,
1456 struct in_device *in_dev,
1457 __be32 daddr, __be32 saddr, u32 tos)
1458 {
1459 struct rtable *rth = NULL;
1460 int err;
1461
1462 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1463 if (res->fi && res->fi->fib_nhs > 1)
1464 fib_select_multipath(res);
1465 #endif
1466
1467 /* create a routing cache entry */
1468 err = __mkroute_input(skb, res, in_dev, daddr, saddr, tos, &rth);
1469 if (err)
1470 return err;
1471
1472 skb_dst_set(skb, &rth->dst);
1473 return 0;
1474 }
1475
1476 /*
1477 * NOTE. We drop all the packets that has local source
1478 * addresses, because every properly looped back packet
1479 * must have correct destination already attached by output routine.
1480 *
1481 * Such approach solves two big problems:
1482 * 1. Not simplex devices are handled properly.
1483 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1484 * called with rcu_read_lock()
1485 */
1486
1487 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1488 u8 tos, struct net_device *dev)
1489 {
1490 struct fib_result res;
1491 struct in_device *in_dev = __in_dev_get_rcu(dev);
1492 struct flowi4 fl4;
1493 unsigned int flags = 0;
1494 u32 itag = 0;
1495 struct rtable *rth;
1496 int err = -EINVAL;
1497 struct net *net = dev_net(dev);
1498 bool do_cache;
1499
1500 /* IP on this device is disabled. */
1501
1502 if (!in_dev)
1503 goto out;
1504
1505 /* Check for the most weird martians, which can be not detected
1506 by fib_lookup.
1507 */
1508
1509 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1510 goto martian_source;
1511
1512 res.fi = NULL;
1513 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1514 goto brd_input;
1515
1516 /* Accept zero addresses only to limited broadcast;
1517 * I even do not know to fix it or not. Waiting for complains :-)
1518 */
1519 if (ipv4_is_zeronet(saddr))
1520 goto martian_source;
1521
1522 if (ipv4_is_zeronet(daddr))
1523 goto martian_destination;
1524
1525 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
1526 if (ipv4_is_loopback(daddr))
1527 goto martian_destination;
1528
1529 if (ipv4_is_loopback(saddr))
1530 goto martian_source;
1531 }
1532
1533 /*
1534 * Now we are ready to route packet.
1535 */
1536 fl4.flowi4_oif = 0;
1537 fl4.flowi4_iif = dev->ifindex;
1538 fl4.flowi4_mark = skb->mark;
1539 fl4.flowi4_tos = tos;
1540 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1541 fl4.daddr = daddr;
1542 fl4.saddr = saddr;
1543 err = fib_lookup(net, &fl4, &res);
1544 if (err != 0)
1545 goto no_route;
1546
1547 RT_CACHE_STAT_INC(in_slow_tot);
1548
1549 if (res.type == RTN_BROADCAST)
1550 goto brd_input;
1551
1552 if (res.type == RTN_LOCAL) {
1553 err = fib_validate_source(skb, saddr, daddr, tos,
1554 net->loopback_dev->ifindex,
1555 dev, in_dev, &itag);
1556 if (err < 0)
1557 goto martian_source_keep_err;
1558 goto local_input;
1559 }
1560
1561 if (!IN_DEV_FORWARD(in_dev))
1562 goto no_route;
1563 if (res.type != RTN_UNICAST)
1564 goto martian_destination;
1565
1566 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1567 out: return err;
1568
1569 brd_input:
1570 if (skb->protocol != htons(ETH_P_IP))
1571 goto e_inval;
1572
1573 if (!ipv4_is_zeronet(saddr)) {
1574 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1575 in_dev, &itag);
1576 if (err < 0)
1577 goto martian_source_keep_err;
1578 }
1579 flags |= RTCF_BROADCAST;
1580 res.type = RTN_BROADCAST;
1581 RT_CACHE_STAT_INC(in_brd);
1582
1583 local_input:
1584 do_cache = false;
1585 if (res.fi) {
1586 if (!itag) {
1587 rth = FIB_RES_NH(res).nh_rth_input;
1588 if (rt_cache_valid(rth)) {
1589 dst_hold(&rth->dst);
1590 goto set_and_out;
1591 }
1592 do_cache = true;
1593 }
1594 }
1595
1596 rth = rt_dst_alloc(net->loopback_dev,
1597 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1598 if (!rth)
1599 goto e_nobufs;
1600
1601 rth->dst.input= ip_local_deliver;
1602 rth->dst.output= ip_rt_bug;
1603 #ifdef CONFIG_IP_ROUTE_CLASSID
1604 rth->dst.tclassid = itag;
1605 #endif
1606
1607 rth->rt_genid = rt_genid(net);
1608 rth->rt_flags = flags|RTCF_LOCAL;
1609 rth->rt_type = res.type;
1610 rth->rt_is_input = 1;
1611 rth->rt_iif = 0;
1612 rth->rt_pmtu = 0;
1613 rth->rt_gateway = 0;
1614 if (res.type == RTN_UNREACHABLE) {
1615 rth->dst.input= ip_error;
1616 rth->dst.error= -err;
1617 rth->rt_flags &= ~RTCF_LOCAL;
1618 }
1619 if (do_cache)
1620 rt_cache_route(&FIB_RES_NH(res), rth);
1621 set_and_out:
1622 skb_dst_set(skb, &rth->dst);
1623 err = 0;
1624 goto out;
1625
1626 no_route:
1627 RT_CACHE_STAT_INC(in_no_route);
1628 res.type = RTN_UNREACHABLE;
1629 if (err == -ESRCH)
1630 err = -ENETUNREACH;
1631 goto local_input;
1632
1633 /*
1634 * Do not cache martian addresses: they should be logged (RFC1812)
1635 */
1636 martian_destination:
1637 RT_CACHE_STAT_INC(in_martian_dst);
1638 #ifdef CONFIG_IP_ROUTE_VERBOSE
1639 if (IN_DEV_LOG_MARTIANS(in_dev))
1640 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1641 &daddr, &saddr, dev->name);
1642 #endif
1643
1644 e_inval:
1645 err = -EINVAL;
1646 goto out;
1647
1648 e_nobufs:
1649 err = -ENOBUFS;
1650 goto out;
1651
1652 martian_source:
1653 err = -EINVAL;
1654 martian_source_keep_err:
1655 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1656 goto out;
1657 }
1658
1659 int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1660 u8 tos, struct net_device *dev)
1661 {
1662 int res;
1663
1664 rcu_read_lock();
1665
1666 /* Multicast recognition logic is moved from route cache to here.
1667 The problem was that too many Ethernet cards have broken/missing
1668 hardware multicast filters :-( As result the host on multicasting
1669 network acquires a lot of useless route cache entries, sort of
1670 SDR messages from all the world. Now we try to get rid of them.
1671 Really, provided software IP multicast filter is organized
1672 reasonably (at least, hashed), it does not result in a slowdown
1673 comparing with route cache reject entries.
1674 Note, that multicast routers are not affected, because
1675 route cache entry is created eventually.
1676 */
1677 if (ipv4_is_multicast(daddr)) {
1678 struct in_device *in_dev = __in_dev_get_rcu(dev);
1679
1680 if (in_dev) {
1681 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1682 ip_hdr(skb)->protocol);
1683 if (our
1684 #ifdef CONFIG_IP_MROUTE
1685 ||
1686 (!ipv4_is_local_multicast(daddr) &&
1687 IN_DEV_MFORWARD(in_dev))
1688 #endif
1689 ) {
1690 int res = ip_route_input_mc(skb, daddr, saddr,
1691 tos, dev, our);
1692 rcu_read_unlock();
1693 return res;
1694 }
1695 }
1696 rcu_read_unlock();
1697 return -EINVAL;
1698 }
1699 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1700 rcu_read_unlock();
1701 return res;
1702 }
1703 EXPORT_SYMBOL(ip_route_input);
1704
1705 /* called with rcu_read_lock() */
1706 static struct rtable *__mkroute_output(const struct fib_result *res,
1707 const struct flowi4 *fl4, int orig_oif,
1708 struct net_device *dev_out,
1709 unsigned int flags)
1710 {
1711 struct fib_info *fi = res->fi;
1712 struct fib_nh_exception *fnhe;
1713 struct in_device *in_dev;
1714 u16 type = res->type;
1715 struct rtable *rth;
1716
1717 in_dev = __in_dev_get_rcu(dev_out);
1718 if (!in_dev)
1719 return ERR_PTR(-EINVAL);
1720
1721 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1722 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
1723 return ERR_PTR(-EINVAL);
1724
1725 if (ipv4_is_lbcast(fl4->daddr))
1726 type = RTN_BROADCAST;
1727 else if (ipv4_is_multicast(fl4->daddr))
1728 type = RTN_MULTICAST;
1729 else if (ipv4_is_zeronet(fl4->daddr))
1730 return ERR_PTR(-EINVAL);
1731
1732 if (dev_out->flags & IFF_LOOPBACK)
1733 flags |= RTCF_LOCAL;
1734
1735 if (type == RTN_BROADCAST) {
1736 flags |= RTCF_BROADCAST | RTCF_LOCAL;
1737 fi = NULL;
1738 } else if (type == RTN_MULTICAST) {
1739 flags |= RTCF_MULTICAST | RTCF_LOCAL;
1740 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
1741 fl4->flowi4_proto))
1742 flags &= ~RTCF_LOCAL;
1743 /* If multicast route do not exist use
1744 * default one, but do not gateway in this case.
1745 * Yes, it is hack.
1746 */
1747 if (fi && res->prefixlen < 4)
1748 fi = NULL;
1749 }
1750
1751 fnhe = NULL;
1752 if (fi) {
1753 fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);
1754 if (!fnhe) {
1755 rth = FIB_RES_NH(*res).nh_rth_output;
1756 if (rt_cache_valid(rth)) {
1757 dst_hold(&rth->dst);
1758 return rth;
1759 }
1760 }
1761 }
1762 rth = rt_dst_alloc(dev_out,
1763 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1764 IN_DEV_CONF_GET(in_dev, NOXFRM),
1765 fi && !fnhe);
1766 if (!rth)
1767 return ERR_PTR(-ENOBUFS);
1768
1769 rth->dst.output = ip_output;
1770
1771 rth->rt_genid = rt_genid(dev_net(dev_out));
1772 rth->rt_flags = flags;
1773 rth->rt_type = type;
1774 rth->rt_is_input = 0;
1775 rth->rt_iif = orig_oif ? : 0;
1776 rth->rt_pmtu = 0;
1777 rth->rt_gateway = 0;
1778
1779 RT_CACHE_STAT_INC(out_slow_tot);
1780
1781 if (flags & RTCF_LOCAL)
1782 rth->dst.input = ip_local_deliver;
1783 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1784 if (flags & RTCF_LOCAL &&
1785 !(dev_out->flags & IFF_LOOPBACK)) {
1786 rth->dst.output = ip_mc_output;
1787 RT_CACHE_STAT_INC(out_slow_mc);
1788 }
1789 #ifdef CONFIG_IP_MROUTE
1790 if (type == RTN_MULTICAST) {
1791 if (IN_DEV_MFORWARD(in_dev) &&
1792 !ipv4_is_local_multicast(fl4->daddr)) {
1793 rth->dst.input = ip_mr_input;
1794 rth->dst.output = ip_mc_output;
1795 }
1796 }
1797 #endif
1798 }
1799
1800 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
1801
1802 return rth;
1803 }
1804
1805 /*
1806 * Major route resolver routine.
1807 */
1808
1809 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
1810 {
1811 struct net_device *dev_out = NULL;
1812 __u8 tos = RT_FL_TOS(fl4);
1813 unsigned int flags = 0;
1814 struct fib_result res;
1815 struct rtable *rth;
1816 int orig_oif;
1817
1818 res.tclassid = 0;
1819 res.fi = NULL;
1820 res.table = NULL;
1821
1822 orig_oif = fl4->flowi4_oif;
1823
1824 fl4->flowi4_iif = net->loopback_dev->ifindex;
1825 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
1826 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
1827 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
1828
1829 rcu_read_lock();
1830 if (fl4->saddr) {
1831 rth = ERR_PTR(-EINVAL);
1832 if (ipv4_is_multicast(fl4->saddr) ||
1833 ipv4_is_lbcast(fl4->saddr) ||
1834 ipv4_is_zeronet(fl4->saddr))
1835 goto out;
1836
1837 /* I removed check for oif == dev_out->oif here.
1838 It was wrong for two reasons:
1839 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
1840 is assigned to multiple interfaces.
1841 2. Moreover, we are allowed to send packets with saddr
1842 of another iface. --ANK
1843 */
1844
1845 if (fl4->flowi4_oif == 0 &&
1846 (ipv4_is_multicast(fl4->daddr) ||
1847 ipv4_is_lbcast(fl4->daddr))) {
1848 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1849 dev_out = __ip_dev_find(net, fl4->saddr, false);
1850 if (dev_out == NULL)
1851 goto out;
1852
1853 /* Special hack: user can direct multicasts
1854 and limited broadcast via necessary interface
1855 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
1856 This hack is not just for fun, it allows
1857 vic,vat and friends to work.
1858 They bind socket to loopback, set ttl to zero
1859 and expect that it will work.
1860 From the viewpoint of routing cache they are broken,
1861 because we are not allowed to build multicast path
1862 with loopback source addr (look, routing cache
1863 cannot know, that ttl is zero, so that packet
1864 will not leave this host and route is valid).
1865 Luckily, this hack is good workaround.
1866 */
1867
1868 fl4->flowi4_oif = dev_out->ifindex;
1869 goto make_route;
1870 }
1871
1872 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
1873 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1874 if (!__ip_dev_find(net, fl4->saddr, false))
1875 goto out;
1876 }
1877 }
1878
1879
1880 if (fl4->flowi4_oif) {
1881 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
1882 rth = ERR_PTR(-ENODEV);
1883 if (dev_out == NULL)
1884 goto out;
1885
1886 /* RACE: Check return value of inet_select_addr instead. */
1887 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
1888 rth = ERR_PTR(-ENETUNREACH);
1889 goto out;
1890 }
1891 if (ipv4_is_local_multicast(fl4->daddr) ||
1892 ipv4_is_lbcast(fl4->daddr)) {
1893 if (!fl4->saddr)
1894 fl4->saddr = inet_select_addr(dev_out, 0,
1895 RT_SCOPE_LINK);
1896 goto make_route;
1897 }
1898 if (fl4->saddr) {
1899 if (ipv4_is_multicast(fl4->daddr))
1900 fl4->saddr = inet_select_addr(dev_out, 0,
1901 fl4->flowi4_scope);
1902 else if (!fl4->daddr)
1903 fl4->saddr = inet_select_addr(dev_out, 0,
1904 RT_SCOPE_HOST);
1905 }
1906 }
1907
1908 if (!fl4->daddr) {
1909 fl4->daddr = fl4->saddr;
1910 if (!fl4->daddr)
1911 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
1912 dev_out = net->loopback_dev;
1913 fl4->flowi4_oif = net->loopback_dev->ifindex;
1914 res.type = RTN_LOCAL;
1915 flags |= RTCF_LOCAL;
1916 goto make_route;
1917 }
1918
1919 if (fib_lookup(net, fl4, &res)) {
1920 res.fi = NULL;
1921 res.table = NULL;
1922 if (fl4->flowi4_oif) {
1923 /* Apparently, routing tables are wrong. Assume,
1924 that the destination is on link.
1925
1926 WHY? DW.
1927 Because we are allowed to send to iface
1928 even if it has NO routes and NO assigned
1929 addresses. When oif is specified, routing
1930 tables are looked up with only one purpose:
1931 to catch if destination is gatewayed, rather than
1932 direct. Moreover, if MSG_DONTROUTE is set,
1933 we send packet, ignoring both routing tables
1934 and ifaddr state. --ANK
1935
1936
1937 We could make it even if oif is unknown,
1938 likely IPv6, but we do not.
1939 */
1940
1941 if (fl4->saddr == 0)
1942 fl4->saddr = inet_select_addr(dev_out, 0,
1943 RT_SCOPE_LINK);
1944 res.type = RTN_UNICAST;
1945 goto make_route;
1946 }
1947 rth = ERR_PTR(-ENETUNREACH);
1948 goto out;
1949 }
1950
1951 if (res.type == RTN_LOCAL) {
1952 if (!fl4->saddr) {
1953 if (res.fi->fib_prefsrc)
1954 fl4->saddr = res.fi->fib_prefsrc;
1955 else
1956 fl4->saddr = fl4->daddr;
1957 }
1958 dev_out = net->loopback_dev;
1959 fl4->flowi4_oif = dev_out->ifindex;
1960 res.fi = NULL;
1961 flags |= RTCF_LOCAL;
1962 goto make_route;
1963 }
1964
1965 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1966 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
1967 fib_select_multipath(&res);
1968 else
1969 #endif
1970 if (!res.prefixlen &&
1971 res.table->tb_num_default > 1 &&
1972 res.type == RTN_UNICAST && !fl4->flowi4_oif)
1973 fib_select_default(&res);
1974
1975 if (!fl4->saddr)
1976 fl4->saddr = FIB_RES_PREFSRC(net, res);
1977
1978 dev_out = FIB_RES_DEV(res);
1979 fl4->flowi4_oif = dev_out->ifindex;
1980
1981
1982 make_route:
1983 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
1984
1985 out:
1986 rcu_read_unlock();
1987 return rth;
1988 }
1989 EXPORT_SYMBOL_GPL(__ip_route_output_key);
1990
1991 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
1992 {
1993 return NULL;
1994 }
1995
1996 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
1997 {
1998 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
1999
2000 return mtu ? : dst->dev->mtu;
2001 }
2002
2003 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2004 struct sk_buff *skb, u32 mtu)
2005 {
2006 }
2007
2008 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2009 struct sk_buff *skb)
2010 {
2011 }
2012
2013 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2014 unsigned long old)
2015 {
2016 return NULL;
2017 }
2018
2019 static struct dst_ops ipv4_dst_blackhole_ops = {
2020 .family = AF_INET,
2021 .protocol = cpu_to_be16(ETH_P_IP),
2022 .check = ipv4_blackhole_dst_check,
2023 .mtu = ipv4_blackhole_mtu,
2024 .default_advmss = ipv4_default_advmss,
2025 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2026 .redirect = ipv4_rt_blackhole_redirect,
2027 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2028 .neigh_lookup = ipv4_neigh_lookup,
2029 };
2030
2031 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2032 {
2033 struct rtable *ort = (struct rtable *) dst_orig;
2034 struct rtable *rt;
2035
2036 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2037 if (rt) {
2038 struct dst_entry *new = &rt->dst;
2039
2040 new->__use = 1;
2041 new->input = dst_discard;
2042 new->output = dst_discard;
2043
2044 new->dev = ort->dst.dev;
2045 if (new->dev)
2046 dev_hold(new->dev);
2047
2048 rt->rt_is_input = ort->rt_is_input;
2049 rt->rt_iif = ort->rt_iif;
2050 rt->rt_pmtu = ort->rt_pmtu;
2051
2052 rt->rt_genid = rt_genid(net);
2053 rt->rt_flags = ort->rt_flags;
2054 rt->rt_type = ort->rt_type;
2055 rt->rt_gateway = ort->rt_gateway;
2056
2057 dst_free(new);
2058 }
2059
2060 dst_release(dst_orig);
2061
2062 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2063 }
2064
2065 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2066 struct sock *sk)
2067 {
2068 struct rtable *rt = __ip_route_output_key(net, flp4);
2069
2070 if (IS_ERR(rt))
2071 return rt;
2072
2073 if (flp4->flowi4_proto)
2074 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2075 flowi4_to_flowi(flp4),
2076 sk, 0);
2077
2078 return rt;
2079 }
2080 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2081
2082 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2083 struct flowi4 *fl4, struct sk_buff *skb, u32 pid,
2084 u32 seq, int event, int nowait, unsigned int flags)
2085 {
2086 struct rtable *rt = skb_rtable(skb);
2087 struct rtmsg *r;
2088 struct nlmsghdr *nlh;
2089 unsigned long expires = 0;
2090 u32 error;
2091 u32 metrics[RTAX_MAX];
2092
2093 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2094 if (nlh == NULL)
2095 return -EMSGSIZE;
2096
2097 r = nlmsg_data(nlh);
2098 r->rtm_family = AF_INET;
2099 r->rtm_dst_len = 32;
2100 r->rtm_src_len = 0;
2101 r->rtm_tos = fl4->flowi4_tos;
2102 r->rtm_table = RT_TABLE_MAIN;
2103 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2104 goto nla_put_failure;
2105 r->rtm_type = rt->rt_type;
2106 r->rtm_scope = RT_SCOPE_UNIVERSE;
2107 r->rtm_protocol = RTPROT_UNSPEC;
2108 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2109 if (rt->rt_flags & RTCF_NOTIFY)
2110 r->rtm_flags |= RTM_F_NOTIFY;
2111
2112 if (nla_put_be32(skb, RTA_DST, dst))
2113 goto nla_put_failure;
2114 if (src) {
2115 r->rtm_src_len = 32;
2116 if (nla_put_be32(skb, RTA_SRC, src))
2117 goto nla_put_failure;
2118 }
2119 if (rt->dst.dev &&
2120 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2121 goto nla_put_failure;
2122 #ifdef CONFIG_IP_ROUTE_CLASSID
2123 if (rt->dst.tclassid &&
2124 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2125 goto nla_put_failure;
2126 #endif
2127 if (!rt_is_input_route(rt) &&
2128 fl4->saddr != src) {
2129 if (nla_put_be32(skb, RTA_PREFSRC, fl4->saddr))
2130 goto nla_put_failure;
2131 }
2132 if (rt->rt_gateway &&
2133 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2134 goto nla_put_failure;
2135
2136 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2137 if (rt->rt_pmtu)
2138 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2139 if (rtnetlink_put_metrics(skb, metrics) < 0)
2140 goto nla_put_failure;
2141
2142 if (fl4->flowi4_mark &&
2143 nla_put_be32(skb, RTA_MARK, fl4->flowi4_mark))
2144 goto nla_put_failure;
2145
2146 error = rt->dst.error;
2147 expires = rt->dst.expires;
2148 if (expires) {
2149 if (time_before(jiffies, expires))
2150 expires -= jiffies;
2151 else
2152 expires = 0;
2153 }
2154
2155 if (rt_is_input_route(rt)) {
2156 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
2157 goto nla_put_failure;
2158 }
2159
2160 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2161 goto nla_put_failure;
2162
2163 return nlmsg_end(skb, nlh);
2164
2165 nla_put_failure:
2166 nlmsg_cancel(skb, nlh);
2167 return -EMSGSIZE;
2168 }
2169
2170 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
2171 {
2172 struct net *net = sock_net(in_skb->sk);
2173 struct rtmsg *rtm;
2174 struct nlattr *tb[RTA_MAX+1];
2175 struct rtable *rt = NULL;
2176 struct flowi4 fl4;
2177 __be32 dst = 0;
2178 __be32 src = 0;
2179 u32 iif;
2180 int err;
2181 int mark;
2182 struct sk_buff *skb;
2183
2184 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2185 if (err < 0)
2186 goto errout;
2187
2188 rtm = nlmsg_data(nlh);
2189
2190 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2191 if (skb == NULL) {
2192 err = -ENOBUFS;
2193 goto errout;
2194 }
2195
2196 /* Reserve room for dummy headers, this skb can pass
2197 through good chunk of routing engine.
2198 */
2199 skb_reset_mac_header(skb);
2200 skb_reset_network_header(skb);
2201
2202 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2203 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2204 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2205
2206 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2207 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2208 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2209 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2210
2211 memset(&fl4, 0, sizeof(fl4));
2212 fl4.daddr = dst;
2213 fl4.saddr = src;
2214 fl4.flowi4_tos = rtm->rtm_tos;
2215 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2216 fl4.flowi4_mark = mark;
2217
2218 if (iif) {
2219 struct net_device *dev;
2220
2221 dev = __dev_get_by_index(net, iif);
2222 if (dev == NULL) {
2223 err = -ENODEV;
2224 goto errout_free;
2225 }
2226
2227 skb->protocol = htons(ETH_P_IP);
2228 skb->dev = dev;
2229 skb->mark = mark;
2230 local_bh_disable();
2231 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2232 local_bh_enable();
2233
2234 rt = skb_rtable(skb);
2235 if (err == 0 && rt->dst.error)
2236 err = -rt->dst.error;
2237 } else {
2238 rt = ip_route_output_key(net, &fl4);
2239
2240 err = 0;
2241 if (IS_ERR(rt))
2242 err = PTR_ERR(rt);
2243 }
2244
2245 if (err)
2246 goto errout_free;
2247
2248 skb_dst_set(skb, &rt->dst);
2249 if (rtm->rtm_flags & RTM_F_NOTIFY)
2250 rt->rt_flags |= RTCF_NOTIFY;
2251
2252 err = rt_fill_info(net, dst, src, &fl4, skb,
2253 NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2254 RTM_NEWROUTE, 0, 0);
2255 if (err <= 0)
2256 goto errout_free;
2257
2258 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2259 errout:
2260 return err;
2261
2262 errout_free:
2263 kfree_skb(skb);
2264 goto errout;
2265 }
2266
2267 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
2268 {
2269 return skb->len;
2270 }
2271
2272 void ip_rt_multicast_event(struct in_device *in_dev)
2273 {
2274 rt_cache_flush(dev_net(in_dev->dev), 0);
2275 }
2276
2277 #ifdef CONFIG_SYSCTL
2278 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
2279 void __user *buffer,
2280 size_t *lenp, loff_t *ppos)
2281 {
2282 if (write) {
2283 int flush_delay;
2284 ctl_table ctl;
2285 struct net *net;
2286
2287 memcpy(&ctl, __ctl, sizeof(ctl));
2288 ctl.data = &flush_delay;
2289 proc_dointvec(&ctl, write, buffer, lenp, ppos);
2290
2291 net = (struct net *)__ctl->extra1;
2292 rt_cache_flush(net, flush_delay);
2293 return 0;
2294 }
2295
2296 return -EINVAL;
2297 }
2298
2299 static ctl_table ipv4_route_table[] = {
2300 {
2301 .procname = "gc_thresh",
2302 .data = &ipv4_dst_ops.gc_thresh,
2303 .maxlen = sizeof(int),
2304 .mode = 0644,
2305 .proc_handler = proc_dointvec,
2306 },
2307 {
2308 .procname = "max_size",
2309 .data = &ip_rt_max_size,
2310 .maxlen = sizeof(int),
2311 .mode = 0644,
2312 .proc_handler = proc_dointvec,
2313 },
2314 {
2315 /* Deprecated. Use gc_min_interval_ms */
2316
2317 .procname = "gc_min_interval",
2318 .data = &ip_rt_gc_min_interval,
2319 .maxlen = sizeof(int),
2320 .mode = 0644,
2321 .proc_handler = proc_dointvec_jiffies,
2322 },
2323 {
2324 .procname = "gc_min_interval_ms",
2325 .data = &ip_rt_gc_min_interval,
2326 .maxlen = sizeof(int),
2327 .mode = 0644,
2328 .proc_handler = proc_dointvec_ms_jiffies,
2329 },
2330 {
2331 .procname = "gc_timeout",
2332 .data = &ip_rt_gc_timeout,
2333 .maxlen = sizeof(int),
2334 .mode = 0644,
2335 .proc_handler = proc_dointvec_jiffies,
2336 },
2337 {
2338 .procname = "gc_interval",
2339 .data = &ip_rt_gc_interval,
2340 .maxlen = sizeof(int),
2341 .mode = 0644,
2342 .proc_handler = proc_dointvec_jiffies,
2343 },
2344 {
2345 .procname = "redirect_load",
2346 .data = &ip_rt_redirect_load,
2347 .maxlen = sizeof(int),
2348 .mode = 0644,
2349 .proc_handler = proc_dointvec,
2350 },
2351 {
2352 .procname = "redirect_number",
2353 .data = &ip_rt_redirect_number,
2354 .maxlen = sizeof(int),
2355 .mode = 0644,
2356 .proc_handler = proc_dointvec,
2357 },
2358 {
2359 .procname = "redirect_silence",
2360 .data = &ip_rt_redirect_silence,
2361 .maxlen = sizeof(int),
2362 .mode = 0644,
2363 .proc_handler = proc_dointvec,
2364 },
2365 {
2366 .procname = "error_cost",
2367 .data = &ip_rt_error_cost,
2368 .maxlen = sizeof(int),
2369 .mode = 0644,
2370 .proc_handler = proc_dointvec,
2371 },
2372 {
2373 .procname = "error_burst",
2374 .data = &ip_rt_error_burst,
2375 .maxlen = sizeof(int),
2376 .mode = 0644,
2377 .proc_handler = proc_dointvec,
2378 },
2379 {
2380 .procname = "gc_elasticity",
2381 .data = &ip_rt_gc_elasticity,
2382 .maxlen = sizeof(int),
2383 .mode = 0644,
2384 .proc_handler = proc_dointvec,
2385 },
2386 {
2387 .procname = "mtu_expires",
2388 .data = &ip_rt_mtu_expires,
2389 .maxlen = sizeof(int),
2390 .mode = 0644,
2391 .proc_handler = proc_dointvec_jiffies,
2392 },
2393 {
2394 .procname = "min_pmtu",
2395 .data = &ip_rt_min_pmtu,
2396 .maxlen = sizeof(int),
2397 .mode = 0644,
2398 .proc_handler = proc_dointvec,
2399 },
2400 {
2401 .procname = "min_adv_mss",
2402 .data = &ip_rt_min_advmss,
2403 .maxlen = sizeof(int),
2404 .mode = 0644,
2405 .proc_handler = proc_dointvec,
2406 },
2407 { }
2408 };
2409
2410 static struct ctl_table ipv4_route_flush_table[] = {
2411 {
2412 .procname = "flush",
2413 .maxlen = sizeof(int),
2414 .mode = 0200,
2415 .proc_handler = ipv4_sysctl_rtcache_flush,
2416 },
2417 { },
2418 };
2419
2420 static __net_init int sysctl_route_net_init(struct net *net)
2421 {
2422 struct ctl_table *tbl;
2423
2424 tbl = ipv4_route_flush_table;
2425 if (!net_eq(net, &init_net)) {
2426 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2427 if (tbl == NULL)
2428 goto err_dup;
2429 }
2430 tbl[0].extra1 = net;
2431
2432 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2433 if (net->ipv4.route_hdr == NULL)
2434 goto err_reg;
2435 return 0;
2436
2437 err_reg:
2438 if (tbl != ipv4_route_flush_table)
2439 kfree(tbl);
2440 err_dup:
2441 return -ENOMEM;
2442 }
2443
2444 static __net_exit void sysctl_route_net_exit(struct net *net)
2445 {
2446 struct ctl_table *tbl;
2447
2448 tbl = net->ipv4.route_hdr->ctl_table_arg;
2449 unregister_net_sysctl_table(net->ipv4.route_hdr);
2450 BUG_ON(tbl == ipv4_route_flush_table);
2451 kfree(tbl);
2452 }
2453
2454 static __net_initdata struct pernet_operations sysctl_route_ops = {
2455 .init = sysctl_route_net_init,
2456 .exit = sysctl_route_net_exit,
2457 };
2458 #endif
2459
2460 static __net_init int rt_genid_init(struct net *net)
2461 {
2462 get_random_bytes(&net->ipv4.rt_genid,
2463 sizeof(net->ipv4.rt_genid));
2464 get_random_bytes(&net->ipv4.dev_addr_genid,
2465 sizeof(net->ipv4.dev_addr_genid));
2466 return 0;
2467 }
2468
2469 static __net_initdata struct pernet_operations rt_genid_ops = {
2470 .init = rt_genid_init,
2471 };
2472
2473 static int __net_init ipv4_inetpeer_init(struct net *net)
2474 {
2475 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2476
2477 if (!bp)
2478 return -ENOMEM;
2479 inet_peer_base_init(bp);
2480 net->ipv4.peers = bp;
2481 return 0;
2482 }
2483
2484 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2485 {
2486 struct inet_peer_base *bp = net->ipv4.peers;
2487
2488 net->ipv4.peers = NULL;
2489 inetpeer_invalidate_tree(bp);
2490 kfree(bp);
2491 }
2492
2493 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2494 .init = ipv4_inetpeer_init,
2495 .exit = ipv4_inetpeer_exit,
2496 };
2497
2498 #ifdef CONFIG_IP_ROUTE_CLASSID
2499 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2500 #endif /* CONFIG_IP_ROUTE_CLASSID */
2501
2502 int __init ip_rt_init(void)
2503 {
2504 int rc = 0;
2505
2506 #ifdef CONFIG_IP_ROUTE_CLASSID
2507 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2508 if (!ip_rt_acct)
2509 panic("IP: failed to allocate ip_rt_acct\n");
2510 #endif
2511
2512 ipv4_dst_ops.kmem_cachep =
2513 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2514 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2515
2516 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2517
2518 if (dst_entries_init(&ipv4_dst_ops) < 0)
2519 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2520
2521 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2522 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2523
2524 ipv4_dst_ops.gc_thresh = ~0;
2525 ip_rt_max_size = INT_MAX;
2526
2527 devinet_init();
2528 ip_fib_init();
2529
2530 if (ip_rt_proc_init())
2531 pr_err("Unable to create route proc files\n");
2532 #ifdef CONFIG_XFRM
2533 xfrm_init();
2534 xfrm4_init(ip_rt_max_size);
2535 #endif
2536 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2537
2538 #ifdef CONFIG_SYSCTL
2539 register_pernet_subsys(&sysctl_route_ops);
2540 #endif
2541 register_pernet_subsys(&rt_genid_ops);
2542 register_pernet_subsys(&ipv4_inetpeer_ops);
2543 return rc;
2544 }
2545
2546 #ifdef CONFIG_SYSCTL
2547 /*
2548 * We really need to sanitize the damn ipv4 init order, then all
2549 * this nonsense will go away.
2550 */
2551 void __init ip_static_sysctl_init(void)
2552 {
2553 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2554 }
2555 #endif
Linux kernel - Deliverables
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