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ipv4/route: arg delay is useless in rt_cache_flush()
[linux-2.6.git] / net / ipv4 / route.c
blobf6436d3b207aaa57675a5cd74401367b3b5ee8d9
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/string.h>
74 #include <linux/socket.h>
75 #include <linux/sockios.h>
76 #include <linux/errno.h>
77 #include <linux/in.h>
78 #include <linux/inet.h>
79 #include <linux/netdevice.h>
80 #include <linux/proc_fs.h>
81 #include <linux/init.h>
82 #include <linux/skbuff.h>
83 #include <linux/inetdevice.h>
84 #include <linux/igmp.h>
85 #include <linux/pkt_sched.h>
86 #include <linux/mroute.h>
87 #include <linux/netfilter_ipv4.h>
88 #include <linux/random.h>
89 #include <linux/rcupdate.h>
90 #include <linux/times.h>
91 #include <linux/slab.h>
92 #include <net/dst.h>
93 #include <net/net_namespace.h>
94 #include <net/protocol.h>
95 #include <net/ip.h>
96 #include <net/route.h>
97 #include <net/inetpeer.h>
98 #include <net/sock.h>
99 #include <net/ip_fib.h>
100 #include <net/arp.h>
101 #include <net/tcp.h>
102 #include <net/icmp.h>
103 #include <net/xfrm.h>
104 #include <net/netevent.h>
105 #include <net/rtnetlink.h>
106 #ifdef CONFIG_SYSCTL
107 #include <linux/sysctl.h>
108 #include <linux/kmemleak.h>
109 #endif
110 #include <net/secure_seq.h>
111
112 #define RT_FL_TOS(oldflp4) \
113 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
114
115 #define IP_MAX_MTU 0xFFF0
116
117 #define RT_GC_TIMEOUT (300*HZ)
118
119 static int ip_rt_max_size;
120 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
121 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
122 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
123 static int ip_rt_redirect_number __read_mostly = 9;
124 static int ip_rt_redirect_load __read_mostly = HZ / 50;
125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
126 static int ip_rt_error_cost __read_mostly = HZ;
127 static int ip_rt_error_burst __read_mostly = 5 * HZ;
128 static int ip_rt_gc_elasticity __read_mostly = 8;
129 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
130 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
131 static int ip_rt_min_advmss __read_mostly = 256;
132
133 /*
134 * Interface to generic destination cache.
135 */
136
137 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
138 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
139 static unsigned int ipv4_mtu(const struct dst_entry *dst);
140 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
141 static void ipv4_link_failure(struct sk_buff *skb);
142 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
143 struct sk_buff *skb, u32 mtu);
144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146 static void ipv4_dst_destroy(struct dst_entry *dst);
147
148 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
149 int how)
150 {
151 }
152
153 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
154 {
155 WARN_ON(1);
156 return NULL;
157 }
158
159 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
160 struct sk_buff *skb,
161 const void *daddr);
162
163 static struct dst_ops ipv4_dst_ops = {
164 .family = AF_INET,
165 .protocol = cpu_to_be16(ETH_P_IP),
166 .check = ipv4_dst_check,
167 .default_advmss = ipv4_default_advmss,
168 .mtu = ipv4_mtu,
169 .cow_metrics = ipv4_cow_metrics,
170 .destroy = ipv4_dst_destroy,
171 .ifdown = ipv4_dst_ifdown,
172 .negative_advice = ipv4_negative_advice,
173 .link_failure = ipv4_link_failure,
174 .update_pmtu = ip_rt_update_pmtu,
175 .redirect = ip_do_redirect,
176 .local_out = __ip_local_out,
177 .neigh_lookup = ipv4_neigh_lookup,
178 };
179
180 #define ECN_OR_COST(class) TC_PRIO_##class
181
182 const __u8 ip_tos2prio[16] = {
183 TC_PRIO_BESTEFFORT,
184 ECN_OR_COST(BESTEFFORT),
185 TC_PRIO_BESTEFFORT,
186 ECN_OR_COST(BESTEFFORT),
187 TC_PRIO_BULK,
188 ECN_OR_COST(BULK),
189 TC_PRIO_BULK,
190 ECN_OR_COST(BULK),
191 TC_PRIO_INTERACTIVE,
192 ECN_OR_COST(INTERACTIVE),
193 TC_PRIO_INTERACTIVE,
194 ECN_OR_COST(INTERACTIVE),
195 TC_PRIO_INTERACTIVE_BULK,
196 ECN_OR_COST(INTERACTIVE_BULK),
197 TC_PRIO_INTERACTIVE_BULK,
198 ECN_OR_COST(INTERACTIVE_BULK)
199 };
200 EXPORT_SYMBOL(ip_tos2prio);
201
202 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
203 #define RT_CACHE_STAT_INC(field) __this_cpu_inc(rt_cache_stat.field)
204
205 static inline int rt_genid(struct net *net)
206 {
207 return atomic_read(&net->ipv4.rt_genid);
208 }
209
210 #ifdef CONFIG_PROC_FS
211 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
212 {
213 if (*pos)
214 return NULL;
215 return SEQ_START_TOKEN;
216 }
217
218 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
219 {
220 ++*pos;
221 return NULL;
222 }
223
224 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
225 {
226 }
227
228 static int rt_cache_seq_show(struct seq_file *seq, void *v)
229 {
230 if (v == SEQ_START_TOKEN)
231 seq_printf(seq, "%-127s\n",
232 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
233 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
234 "HHUptod\tSpecDst");
235 return 0;
236 }
237
238 static const struct seq_operations rt_cache_seq_ops = {
239 .start = rt_cache_seq_start,
240 .next = rt_cache_seq_next,
241 .stop = rt_cache_seq_stop,
242 .show = rt_cache_seq_show,
243 };
244
245 static int rt_cache_seq_open(struct inode *inode, struct file *file)
246 {
247 return seq_open(file, &rt_cache_seq_ops);
248 }
249
250 static const struct file_operations rt_cache_seq_fops = {
251 .owner = THIS_MODULE,
252 .open = rt_cache_seq_open,
253 .read = seq_read,
254 .llseek = seq_lseek,
255 .release = seq_release,
256 };
257
258
259 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
260 {
261 int cpu;
262
263 if (*pos == 0)
264 return SEQ_START_TOKEN;
265
266 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
267 if (!cpu_possible(cpu))
268 continue;
269 *pos = cpu+1;
270 return &per_cpu(rt_cache_stat, cpu);
271 }
272 return NULL;
273 }
274
275 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
276 {
277 int cpu;
278
279 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
280 if (!cpu_possible(cpu))
281 continue;
282 *pos = cpu+1;
283 return &per_cpu(rt_cache_stat, cpu);
284 }
285 return NULL;
286
287 }
288
289 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
290 {
291
292 }
293
294 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
295 {
296 struct rt_cache_stat *st = v;
297
298 if (v == SEQ_START_TOKEN) {
299 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");
300 return 0;
301 }
302
303 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
304 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
305 dst_entries_get_slow(&ipv4_dst_ops),
306 st->in_hit,
307 st->in_slow_tot,
308 st->in_slow_mc,
309 st->in_no_route,
310 st->in_brd,
311 st->in_martian_dst,
312 st->in_martian_src,
313
314 st->out_hit,
315 st->out_slow_tot,
316 st->out_slow_mc,
317
318 st->gc_total,
319 st->gc_ignored,
320 st->gc_goal_miss,
321 st->gc_dst_overflow,
322 st->in_hlist_search,
323 st->out_hlist_search
324 );
325 return 0;
326 }
327
328 static const struct seq_operations rt_cpu_seq_ops = {
329 .start = rt_cpu_seq_start,
330 .next = rt_cpu_seq_next,
331 .stop = rt_cpu_seq_stop,
332 .show = rt_cpu_seq_show,
333 };
334
335
336 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
337 {
338 return seq_open(file, &rt_cpu_seq_ops);
339 }
340
341 static const struct file_operations rt_cpu_seq_fops = {
342 .owner = THIS_MODULE,
343 .open = rt_cpu_seq_open,
344 .read = seq_read,
345 .llseek = seq_lseek,
346 .release = seq_release,
347 };
348
349 #ifdef CONFIG_IP_ROUTE_CLASSID
350 static int rt_acct_proc_show(struct seq_file *m, void *v)
351 {
352 struct ip_rt_acct *dst, *src;
353 unsigned int i, j;
354
355 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
356 if (!dst)
357 return -ENOMEM;
358
359 for_each_possible_cpu(i) {
360 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
361 for (j = 0; j < 256; j++) {
362 dst[j].o_bytes += src[j].o_bytes;
363 dst[j].o_packets += src[j].o_packets;
364 dst[j].i_bytes += src[j].i_bytes;
365 dst[j].i_packets += src[j].i_packets;
366 }
367 }
368
369 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
370 kfree(dst);
371 return 0;
372 }
373
374 static int rt_acct_proc_open(struct inode *inode, struct file *file)
375 {
376 return single_open(file, rt_acct_proc_show, NULL);
377 }
378
379 static const struct file_operations rt_acct_proc_fops = {
380 .owner = THIS_MODULE,
381 .open = rt_acct_proc_open,
382 .read = seq_read,
383 .llseek = seq_lseek,
384 .release = single_release,
385 };
386 #endif
387
388 static int __net_init ip_rt_do_proc_init(struct net *net)
389 {
390 struct proc_dir_entry *pde;
391
392 pde = proc_net_fops_create(net, "rt_cache", S_IRUGO,
393 &rt_cache_seq_fops);
394 if (!pde)
395 goto err1;
396
397 pde = proc_create("rt_cache", S_IRUGO,
398 net->proc_net_stat, &rt_cpu_seq_fops);
399 if (!pde)
400 goto err2;
401
402 #ifdef CONFIG_IP_ROUTE_CLASSID
403 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
404 if (!pde)
405 goto err3;
406 #endif
407 return 0;
408
409 #ifdef CONFIG_IP_ROUTE_CLASSID
410 err3:
411 remove_proc_entry("rt_cache", net->proc_net_stat);
412 #endif
413 err2:
414 remove_proc_entry("rt_cache", net->proc_net);
415 err1:
416 return -ENOMEM;
417 }
418
419 static void __net_exit ip_rt_do_proc_exit(struct net *net)
420 {
421 remove_proc_entry("rt_cache", net->proc_net_stat);
422 remove_proc_entry("rt_cache", net->proc_net);
423 #ifdef CONFIG_IP_ROUTE_CLASSID
424 remove_proc_entry("rt_acct", net->proc_net);
425 #endif
426 }
427
428 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
429 .init = ip_rt_do_proc_init,
430 .exit = ip_rt_do_proc_exit,
431 };
432
433 static int __init ip_rt_proc_init(void)
434 {
435 return register_pernet_subsys(&ip_rt_proc_ops);
436 }
437
438 #else
439 static inline int ip_rt_proc_init(void)
440 {
441 return 0;
442 }
443 #endif /* CONFIG_PROC_FS */
444
445 static inline bool rt_is_expired(const struct rtable *rth)
446 {
447 return rth->rt_genid != rt_genid(dev_net(rth->dst.dev));
448 }
449
450 /*
451 * Perturbation of rt_genid by a small quantity [1..256]
452 * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
453 * many times (2^24) without giving recent rt_genid.
454 * Jenkins hash is strong enough that litle changes of rt_genid are OK.
455 */
456 static void rt_cache_invalidate(struct net *net)
457 {
458 unsigned char shuffle;
459
460 get_random_bytes(&shuffle, sizeof(shuffle));
461 atomic_add(shuffle + 1U, &net->ipv4.rt_genid);
462 }
463
464 void rt_cache_flush(struct net *net)
465 {
466 rt_cache_invalidate(net);
467 }
468
469 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
470 struct sk_buff *skb,
471 const void *daddr)
472 {
473 struct net_device *dev = dst->dev;
474 const __be32 *pkey = daddr;
475 const struct rtable *rt;
476 struct neighbour *n;
477
478 rt = (const struct rtable *) dst;
479 if (rt->rt_gateway)
480 pkey = (const __be32 *) &rt->rt_gateway;
481 else if (skb)
482 pkey = &ip_hdr(skb)->daddr;
483
484 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
485 if (n)
486 return n;
487 return neigh_create(&arp_tbl, pkey, dev);
488 }
489
490 /*
491 * Peer allocation may fail only in serious out-of-memory conditions. However
492 * we still can generate some output.
493 * Random ID selection looks a bit dangerous because we have no chances to
494 * select ID being unique in a reasonable period of time.
495 * But broken packet identifier may be better than no packet at all.
496 */
497 static void ip_select_fb_ident(struct iphdr *iph)
498 {
499 static DEFINE_SPINLOCK(ip_fb_id_lock);
500 static u32 ip_fallback_id;
501 u32 salt;
502
503 spin_lock_bh(&ip_fb_id_lock);
504 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
505 iph->id = htons(salt & 0xFFFF);
506 ip_fallback_id = salt;
507 spin_unlock_bh(&ip_fb_id_lock);
508 }
509
510 void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
511 {
512 struct net *net = dev_net(dst->dev);
513 struct inet_peer *peer;
514
515 peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
516 if (peer) {
517 iph->id = htons(inet_getid(peer, more));
518 inet_putpeer(peer);
519 return;
520 }
521
522 ip_select_fb_ident(iph);
523 }
524 EXPORT_SYMBOL(__ip_select_ident);
525
526 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
527 const struct iphdr *iph,
528 int oif, u8 tos,
529 u8 prot, u32 mark, int flow_flags)
530 {
531 if (sk) {
532 const struct inet_sock *inet = inet_sk(sk);
533
534 oif = sk->sk_bound_dev_if;
535 mark = sk->sk_mark;
536 tos = RT_CONN_FLAGS(sk);
537 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
538 }
539 flowi4_init_output(fl4, oif, mark, tos,
540 RT_SCOPE_UNIVERSE, prot,
541 flow_flags,
542 iph->daddr, iph->saddr, 0, 0);
543 }
544
545 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
546 const struct sock *sk)
547 {
548 const struct iphdr *iph = ip_hdr(skb);
549 int oif = skb->dev->ifindex;
550 u8 tos = RT_TOS(iph->tos);
551 u8 prot = iph->protocol;
552 u32 mark = skb->mark;
553
554 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
555 }
556
557 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
558 {
559 const struct inet_sock *inet = inet_sk(sk);
560 const struct ip_options_rcu *inet_opt;
561 __be32 daddr = inet->inet_daddr;
562
563 rcu_read_lock();
564 inet_opt = rcu_dereference(inet->inet_opt);
565 if (inet_opt && inet_opt->opt.srr)
566 daddr = inet_opt->opt.faddr;
567 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
568 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
569 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
570 inet_sk_flowi_flags(sk),
571 daddr, inet->inet_saddr, 0, 0);
572 rcu_read_unlock();
573 }
574
575 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
576 const struct sk_buff *skb)
577 {
578 if (skb)
579 build_skb_flow_key(fl4, skb, sk);
580 else
581 build_sk_flow_key(fl4, sk);
582 }
583
584 static inline void rt_free(struct rtable *rt)
585 {
586 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
587 }
588
589 static DEFINE_SPINLOCK(fnhe_lock);
590
591 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
592 {
593 struct fib_nh_exception *fnhe, *oldest;
594 struct rtable *orig;
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 orig = rcu_dereference(oldest->fnhe_rth);
603 if (orig) {
604 RCU_INIT_POINTER(oldest->fnhe_rth, NULL);
605 rt_free(orig);
606 }
607 return oldest;
608 }
609
610 static inline u32 fnhe_hashfun(__be32 daddr)
611 {
612 u32 hval;
613
614 hval = (__force u32) daddr;
615 hval ^= (hval >> 11) ^ (hval >> 22);
616
617 return hval & (FNHE_HASH_SIZE - 1);
618 }
619
620 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
621 u32 pmtu, unsigned long expires)
622 {
623 struct fnhe_hash_bucket *hash;
624 struct fib_nh_exception *fnhe;
625 int depth;
626 u32 hval = fnhe_hashfun(daddr);
627
628 spin_lock_bh(&fnhe_lock);
629
630 hash = nh->nh_exceptions;
631 if (!hash) {
632 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
633 if (!hash)
634 goto out_unlock;
635 nh->nh_exceptions = hash;
636 }
637
638 hash += hval;
639
640 depth = 0;
641 for (fnhe = rcu_dereference(hash->chain); fnhe;
642 fnhe = rcu_dereference(fnhe->fnhe_next)) {
643 if (fnhe->fnhe_daddr == daddr)
644 break;
645 depth++;
646 }
647
648 if (fnhe) {
649 if (gw)
650 fnhe->fnhe_gw = gw;
651 if (pmtu) {
652 fnhe->fnhe_pmtu = pmtu;
653 fnhe->fnhe_expires = expires;
654 }
655 } else {
656 if (depth > FNHE_RECLAIM_DEPTH)
657 fnhe = fnhe_oldest(hash);
658 else {
659 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
660 if (!fnhe)
661 goto out_unlock;
662
663 fnhe->fnhe_next = hash->chain;
664 rcu_assign_pointer(hash->chain, fnhe);
665 }
666 fnhe->fnhe_daddr = daddr;
667 fnhe->fnhe_gw = gw;
668 fnhe->fnhe_pmtu = pmtu;
669 fnhe->fnhe_expires = expires;
670 }
671
672 fnhe->fnhe_stamp = jiffies;
673
674 out_unlock:
675 spin_unlock_bh(&fnhe_lock);
676 return;
677 }
678
679 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
680 bool kill_route)
681 {
682 __be32 new_gw = icmp_hdr(skb)->un.gateway;
683 __be32 old_gw = ip_hdr(skb)->saddr;
684 struct net_device *dev = skb->dev;
685 struct in_device *in_dev;
686 struct fib_result res;
687 struct neighbour *n;
688 struct net *net;
689
690 switch (icmp_hdr(skb)->code & 7) {
691 case ICMP_REDIR_NET:
692 case ICMP_REDIR_NETTOS:
693 case ICMP_REDIR_HOST:
694 case ICMP_REDIR_HOSTTOS:
695 break;
696
697 default:
698 return;
699 }
700
701 if (rt->rt_gateway != old_gw)
702 return;
703
704 in_dev = __in_dev_get_rcu(dev);
705 if (!in_dev)
706 return;
707
708 net = dev_net(dev);
709 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
710 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
711 ipv4_is_zeronet(new_gw))
712 goto reject_redirect;
713
714 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
715 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
716 goto reject_redirect;
717 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
718 goto reject_redirect;
719 } else {
720 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
721 goto reject_redirect;
722 }
723
724 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
725 if (n) {
726 if (!(n->nud_state & NUD_VALID)) {
727 neigh_event_send(n, NULL);
728 } else {
729 if (fib_lookup(net, fl4, &res) == 0) {
730 struct fib_nh *nh = &FIB_RES_NH(res);
731
732 update_or_create_fnhe(nh, fl4->daddr, new_gw,
733 0, 0);
734 }
735 if (kill_route)
736 rt->dst.obsolete = DST_OBSOLETE_KILL;
737 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
738 }
739 neigh_release(n);
740 }
741 return;
742
743 reject_redirect:
744 #ifdef CONFIG_IP_ROUTE_VERBOSE
745 if (IN_DEV_LOG_MARTIANS(in_dev)) {
746 const struct iphdr *iph = (const struct iphdr *) skb->data;
747 __be32 daddr = iph->daddr;
748 __be32 saddr = iph->saddr;
749
750 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
751 " Advised path = %pI4 -> %pI4\n",
752 &old_gw, dev->name, &new_gw,
753 &saddr, &daddr);
754 }
755 #endif
756 ;
757 }
758
759 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
760 {
761 struct rtable *rt;
762 struct flowi4 fl4;
763
764 rt = (struct rtable *) dst;
765
766 ip_rt_build_flow_key(&fl4, sk, skb);
767 __ip_do_redirect(rt, skb, &fl4, true);
768 }
769
770 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
771 {
772 struct rtable *rt = (struct rtable *)dst;
773 struct dst_entry *ret = dst;
774
775 if (rt) {
776 if (dst->obsolete > 0) {
777 ip_rt_put(rt);
778 ret = NULL;
779 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
780 rt->dst.expires) {
781 ip_rt_put(rt);
782 ret = NULL;
783 }
784 }
785 return ret;
786 }
787
788 /*
789 * Algorithm:
790 * 1. The first ip_rt_redirect_number redirects are sent
791 * with exponential backoff, then we stop sending them at all,
792 * assuming that the host ignores our redirects.
793 * 2. If we did not see packets requiring redirects
794 * during ip_rt_redirect_silence, we assume that the host
795 * forgot redirected route and start to send redirects again.
796 *
797 * This algorithm is much cheaper and more intelligent than dumb load limiting
798 * in icmp.c.
799 *
800 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
801 * and "frag. need" (breaks PMTU discovery) in icmp.c.
802 */
803
804 void ip_rt_send_redirect(struct sk_buff *skb)
805 {
806 struct rtable *rt = skb_rtable(skb);
807 struct in_device *in_dev;
808 struct inet_peer *peer;
809 struct net *net;
810 int log_martians;
811
812 rcu_read_lock();
813 in_dev = __in_dev_get_rcu(rt->dst.dev);
814 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
815 rcu_read_unlock();
816 return;
817 }
818 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
819 rcu_read_unlock();
820
821 net = dev_net(rt->dst.dev);
822 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
823 if (!peer) {
824 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
825 return;
826 }
827
828 /* No redirected packets during ip_rt_redirect_silence;
829 * reset the algorithm.
830 */
831 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
832 peer->rate_tokens = 0;
833
834 /* Too many ignored redirects; do not send anything
835 * set dst.rate_last to the last seen redirected packet.
836 */
837 if (peer->rate_tokens >= ip_rt_redirect_number) {
838 peer->rate_last = jiffies;
839 goto out_put_peer;
840 }
841
842 /* Check for load limit; set rate_last to the latest sent
843 * redirect.
844 */
845 if (peer->rate_tokens == 0 ||
846 time_after(jiffies,
847 (peer->rate_last +
848 (ip_rt_redirect_load << peer->rate_tokens)))) {
849 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
850 peer->rate_last = jiffies;
851 ++peer->rate_tokens;
852 #ifdef CONFIG_IP_ROUTE_VERBOSE
853 if (log_martians &&
854 peer->rate_tokens == ip_rt_redirect_number)
855 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
856 &ip_hdr(skb)->saddr, inet_iif(skb),
857 &ip_hdr(skb)->daddr, &rt->rt_gateway);
858 #endif
859 }
860 out_put_peer:
861 inet_putpeer(peer);
862 }
863
864 static int ip_error(struct sk_buff *skb)
865 {
866 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
867 struct rtable *rt = skb_rtable(skb);
868 struct inet_peer *peer;
869 unsigned long now;
870 struct net *net;
871 bool send;
872 int code;
873
874 net = dev_net(rt->dst.dev);
875 if (!IN_DEV_FORWARD(in_dev)) {
876 switch (rt->dst.error) {
877 case EHOSTUNREACH:
878 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
879 break;
880
881 case ENETUNREACH:
882 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
883 break;
884 }
885 goto out;
886 }
887
888 switch (rt->dst.error) {
889 case EINVAL:
890 default:
891 goto out;
892 case EHOSTUNREACH:
893 code = ICMP_HOST_UNREACH;
894 break;
895 case ENETUNREACH:
896 code = ICMP_NET_UNREACH;
897 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
898 break;
899 case EACCES:
900 code = ICMP_PKT_FILTERED;
901 break;
902 }
903
904 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
905
906 send = true;
907 if (peer) {
908 now = jiffies;
909 peer->rate_tokens += now - peer->rate_last;
910 if (peer->rate_tokens > ip_rt_error_burst)
911 peer->rate_tokens = ip_rt_error_burst;
912 peer->rate_last = now;
913 if (peer->rate_tokens >= ip_rt_error_cost)
914 peer->rate_tokens -= ip_rt_error_cost;
915 else
916 send = false;
917 inet_putpeer(peer);
918 }
919 if (send)
920 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
921
922 out: kfree_skb(skb);
923 return 0;
924 }
925
926 static u32 __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
927 {
928 struct fib_result res;
929
930 if (mtu < ip_rt_min_pmtu)
931 mtu = ip_rt_min_pmtu;
932
933 rcu_read_lock();
934 if (fib_lookup(dev_net(rt->dst.dev), fl4, &res) == 0) {
935 struct fib_nh *nh = &FIB_RES_NH(res);
936
937 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
938 jiffies + ip_rt_mtu_expires);
939 }
940 rcu_read_unlock();
941 return mtu;
942 }
943
944 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
945 struct sk_buff *skb, u32 mtu)
946 {
947 struct rtable *rt = (struct rtable *) dst;
948 struct flowi4 fl4;
949
950 ip_rt_build_flow_key(&fl4, sk, skb);
951 mtu = __ip_rt_update_pmtu(rt, &fl4, mtu);
952
953 if (!rt->rt_pmtu) {
954 dst->obsolete = DST_OBSOLETE_KILL;
955 } else {
956 rt->rt_pmtu = mtu;
957 rt->dst.expires = max(1UL, jiffies + ip_rt_mtu_expires);
958 }
959 }
960
961 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
962 int oif, u32 mark, u8 protocol, int flow_flags)
963 {
964 const struct iphdr *iph = (const struct iphdr *) skb->data;
965 struct flowi4 fl4;
966 struct rtable *rt;
967
968 __build_flow_key(&fl4, NULL, iph, oif,
969 RT_TOS(iph->tos), protocol, mark, flow_flags);
970 rt = __ip_route_output_key(net, &fl4);
971 if (!IS_ERR(rt)) {
972 __ip_rt_update_pmtu(rt, &fl4, mtu);
973 ip_rt_put(rt);
974 }
975 }
976 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
977
978 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
979 {
980 const struct iphdr *iph = (const struct iphdr *) skb->data;
981 struct flowi4 fl4;
982 struct rtable *rt;
983
984 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
985 rt = __ip_route_output_key(sock_net(sk), &fl4);
986 if (!IS_ERR(rt)) {
987 __ip_rt_update_pmtu(rt, &fl4, mtu);
988 ip_rt_put(rt);
989 }
990 }
991 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
992
993 void ipv4_redirect(struct sk_buff *skb, struct net *net,
994 int oif, u32 mark, u8 protocol, int flow_flags)
995 {
996 const struct iphdr *iph = (const struct iphdr *) skb->data;
997 struct flowi4 fl4;
998 struct rtable *rt;
999
1000 __build_flow_key(&fl4, NULL, iph, oif,
1001 RT_TOS(iph->tos), protocol, mark, flow_flags);
1002 rt = __ip_route_output_key(net, &fl4);
1003 if (!IS_ERR(rt)) {
1004 __ip_do_redirect(rt, skb, &fl4, false);
1005 ip_rt_put(rt);
1006 }
1007 }
1008 EXPORT_SYMBOL_GPL(ipv4_redirect);
1009
1010 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1011 {
1012 const struct iphdr *iph = (const struct iphdr *) skb->data;
1013 struct flowi4 fl4;
1014 struct rtable *rt;
1015
1016 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1017 rt = __ip_route_output_key(sock_net(sk), &fl4);
1018 if (!IS_ERR(rt)) {
1019 __ip_do_redirect(rt, skb, &fl4, false);
1020 ip_rt_put(rt);
1021 }
1022 }
1023 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1024
1025 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1026 {
1027 struct rtable *rt = (struct rtable *) dst;
1028
1029 /* All IPV4 dsts are created with ->obsolete set to the value
1030 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1031 * into this function always.
1032 *
1033 * When a PMTU/redirect information update invalidates a
1034 * route, this is indicated by setting obsolete to
1035 * DST_OBSOLETE_KILL.
1036 */
1037 if (dst->obsolete == DST_OBSOLETE_KILL || rt_is_expired(rt))
1038 return NULL;
1039 return dst;
1040 }
1041
1042 static void ipv4_link_failure(struct sk_buff *skb)
1043 {
1044 struct rtable *rt;
1045
1046 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1047
1048 rt = skb_rtable(skb);
1049 if (rt)
1050 dst_set_expires(&rt->dst, 0);
1051 }
1052
1053 static int ip_rt_bug(struct sk_buff *skb)
1054 {
1055 pr_debug("%s: %pI4 -> %pI4, %s\n",
1056 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1057 skb->dev ? skb->dev->name : "?");
1058 kfree_skb(skb);
1059 WARN_ON(1);
1060 return 0;
1061 }
1062
1063 /*
1064 We do not cache source address of outgoing interface,
1065 because it is used only by IP RR, TS and SRR options,
1066 so that it out of fast path.
1067
1068 BTW remember: "addr" is allowed to be not aligned
1069 in IP options!
1070 */
1071
1072 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1073 {
1074 __be32 src;
1075
1076 if (rt_is_output_route(rt))
1077 src = ip_hdr(skb)->saddr;
1078 else {
1079 struct fib_result res;
1080 struct flowi4 fl4;
1081 struct iphdr *iph;
1082
1083 iph = ip_hdr(skb);
1084
1085 memset(&fl4, 0, sizeof(fl4));
1086 fl4.daddr = iph->daddr;
1087 fl4.saddr = iph->saddr;
1088 fl4.flowi4_tos = RT_TOS(iph->tos);
1089 fl4.flowi4_oif = rt->dst.dev->ifindex;
1090 fl4.flowi4_iif = skb->dev->ifindex;
1091 fl4.flowi4_mark = skb->mark;
1092
1093 rcu_read_lock();
1094 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1095 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1096 else
1097 src = inet_select_addr(rt->dst.dev,
1098 rt_nexthop(rt, iph->daddr),
1099 RT_SCOPE_UNIVERSE);
1100 rcu_read_unlock();
1101 }
1102 memcpy(addr, &src, 4);
1103 }
1104
1105 #ifdef CONFIG_IP_ROUTE_CLASSID
1106 static void set_class_tag(struct rtable *rt, u32 tag)
1107 {
1108 if (!(rt->dst.tclassid & 0xFFFF))
1109 rt->dst.tclassid |= tag & 0xFFFF;
1110 if (!(rt->dst.tclassid & 0xFFFF0000))
1111 rt->dst.tclassid |= tag & 0xFFFF0000;
1112 }
1113 #endif
1114
1115 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1116 {
1117 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1118
1119 if (advmss == 0) {
1120 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1121 ip_rt_min_advmss);
1122 if (advmss > 65535 - 40)
1123 advmss = 65535 - 40;
1124 }
1125 return advmss;
1126 }
1127
1128 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1129 {
1130 const struct rtable *rt = (const struct rtable *) dst;
1131 unsigned int mtu = rt->rt_pmtu;
1132
1133 if (mtu && time_after_eq(jiffies, rt->dst.expires))
1134 mtu = 0;
1135
1136 if (!mtu)
1137 mtu = dst_metric_raw(dst, RTAX_MTU);
1138
1139 if (mtu && rt_is_output_route(rt))
1140 return mtu;
1141
1142 mtu = dst->dev->mtu;
1143
1144 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1145 if (rt->rt_gateway && mtu > 576)
1146 mtu = 576;
1147 }
1148
1149 if (mtu > IP_MAX_MTU)
1150 mtu = IP_MAX_MTU;
1151
1152 return mtu;
1153 }
1154
1155 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1156 {
1157 struct fnhe_hash_bucket *hash = nh->nh_exceptions;
1158 struct fib_nh_exception *fnhe;
1159 u32 hval;
1160
1161 if (!hash)
1162 return NULL;
1163
1164 hval = fnhe_hashfun(daddr);
1165
1166 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1167 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1168 if (fnhe->fnhe_daddr == daddr)
1169 return fnhe;
1170 }
1171 return NULL;
1172 }
1173
1174 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1175 __be32 daddr)
1176 {
1177 bool ret = false;
1178
1179 spin_lock_bh(&fnhe_lock);
1180
1181 if (daddr == fnhe->fnhe_daddr) {
1182 struct rtable *orig;
1183
1184 if (fnhe->fnhe_pmtu) {
1185 unsigned long expires = fnhe->fnhe_expires;
1186 unsigned long diff = expires - jiffies;
1187
1188 if (time_before(jiffies, expires)) {
1189 rt->rt_pmtu = fnhe->fnhe_pmtu;
1190 dst_set_expires(&rt->dst, diff);
1191 }
1192 }
1193 if (fnhe->fnhe_gw) {
1194 rt->rt_flags |= RTCF_REDIRECTED;
1195 rt->rt_gateway = fnhe->fnhe_gw;
1196 }
1197
1198 orig = rcu_dereference(fnhe->fnhe_rth);
1199 rcu_assign_pointer(fnhe->fnhe_rth, rt);
1200 if (orig)
1201 rt_free(orig);
1202
1203 fnhe->fnhe_stamp = jiffies;
1204 ret = true;
1205 } else {
1206 /* Routes we intend to cache in nexthop exception have
1207 * the DST_NOCACHE bit clear. However, if we are
1208 * unsuccessful at storing this route into the cache
1209 * we really need to set it.
1210 */
1211 rt->dst.flags |= DST_NOCACHE;
1212 }
1213 spin_unlock_bh(&fnhe_lock);
1214
1215 return ret;
1216 }
1217
1218 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1219 {
1220 struct rtable *orig, *prev, **p;
1221 bool ret = true;
1222
1223 if (rt_is_input_route(rt)) {
1224 p = (struct rtable **)&nh->nh_rth_input;
1225 } else {
1226 if (!nh->nh_pcpu_rth_output)
1227 goto nocache;
1228 p = (struct rtable **)__this_cpu_ptr(nh->nh_pcpu_rth_output);
1229 }
1230 orig = *p;
1231
1232 prev = cmpxchg(p, orig, rt);
1233 if (prev == orig) {
1234 if (orig)
1235 rt_free(orig);
1236 } else {
1237 /* Routes we intend to cache in the FIB nexthop have
1238 * the DST_NOCACHE bit clear. However, if we are
1239 * unsuccessful at storing this route into the cache
1240 * we really need to set it.
1241 */
1242 nocache:
1243 rt->dst.flags |= DST_NOCACHE;
1244 ret = false;
1245 }
1246
1247 return ret;
1248 }
1249
1250 static DEFINE_SPINLOCK(rt_uncached_lock);
1251 static LIST_HEAD(rt_uncached_list);
1252
1253 static void rt_add_uncached_list(struct rtable *rt)
1254 {
1255 spin_lock_bh(&rt_uncached_lock);
1256 list_add_tail(&rt->rt_uncached, &rt_uncached_list);
1257 spin_unlock_bh(&rt_uncached_lock);
1258 }
1259
1260 static void ipv4_dst_destroy(struct dst_entry *dst)
1261 {
1262 struct rtable *rt = (struct rtable *) dst;
1263
1264 if (!list_empty(&rt->rt_uncached)) {
1265 spin_lock_bh(&rt_uncached_lock);
1266 list_del(&rt->rt_uncached);
1267 spin_unlock_bh(&rt_uncached_lock);
1268 }
1269 }
1270
1271 void rt_flush_dev(struct net_device *dev)
1272 {
1273 if (!list_empty(&rt_uncached_list)) {
1274 struct net *net = dev_net(dev);
1275 struct rtable *rt;
1276
1277 spin_lock_bh(&rt_uncached_lock);
1278 list_for_each_entry(rt, &rt_uncached_list, rt_uncached) {
1279 if (rt->dst.dev != dev)
1280 continue;
1281 rt->dst.dev = net->loopback_dev;
1282 dev_hold(rt->dst.dev);
1283 dev_put(dev);
1284 }
1285 spin_unlock_bh(&rt_uncached_lock);
1286 }
1287 }
1288
1289 static bool rt_cache_valid(const struct rtable *rt)
1290 {
1291 return rt &&
1292 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1293 !rt_is_expired(rt);
1294 }
1295
1296 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1297 const struct fib_result *res,
1298 struct fib_nh_exception *fnhe,
1299 struct fib_info *fi, u16 type, u32 itag)
1300 {
1301 bool cached = false;
1302
1303 if (fi) {
1304 struct fib_nh *nh = &FIB_RES_NH(*res);
1305
1306 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK)
1307 rt->rt_gateway = nh->nh_gw;
1308 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1309 #ifdef CONFIG_IP_ROUTE_CLASSID
1310 rt->dst.tclassid = nh->nh_tclassid;
1311 #endif
1312 if (unlikely(fnhe))
1313 cached = rt_bind_exception(rt, fnhe, daddr);
1314 else if (!(rt->dst.flags & DST_NOCACHE))
1315 cached = rt_cache_route(nh, rt);
1316 }
1317 if (unlikely(!cached))
1318 rt_add_uncached_list(rt);
1319
1320 #ifdef CONFIG_IP_ROUTE_CLASSID
1321 #ifdef CONFIG_IP_MULTIPLE_TABLES
1322 set_class_tag(rt, res->tclassid);
1323 #endif
1324 set_class_tag(rt, itag);
1325 #endif
1326 }
1327
1328 static struct rtable *rt_dst_alloc(struct net_device *dev,
1329 bool nopolicy, bool noxfrm, bool will_cache)
1330 {
1331 return dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1332 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1333 (nopolicy ? DST_NOPOLICY : 0) |
1334 (noxfrm ? DST_NOXFRM : 0));
1335 }
1336
1337 /* called in rcu_read_lock() section */
1338 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1339 u8 tos, struct net_device *dev, int our)
1340 {
1341 struct rtable *rth;
1342 struct in_device *in_dev = __in_dev_get_rcu(dev);
1343 u32 itag = 0;
1344 int err;
1345
1346 /* Primary sanity checks. */
1347
1348 if (in_dev == NULL)
1349 return -EINVAL;
1350
1351 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1352 skb->protocol != htons(ETH_P_IP))
1353 goto e_inval;
1354
1355 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1356 if (ipv4_is_loopback(saddr))
1357 goto e_inval;
1358
1359 if (ipv4_is_zeronet(saddr)) {
1360 if (!ipv4_is_local_multicast(daddr))
1361 goto e_inval;
1362 } else {
1363 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1364 in_dev, &itag);
1365 if (err < 0)
1366 goto e_err;
1367 }
1368 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1369 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1370 if (!rth)
1371 goto e_nobufs;
1372
1373 #ifdef CONFIG_IP_ROUTE_CLASSID
1374 rth->dst.tclassid = itag;
1375 #endif
1376 rth->dst.output = ip_rt_bug;
1377
1378 rth->rt_genid = rt_genid(dev_net(dev));
1379 rth->rt_flags = RTCF_MULTICAST;
1380 rth->rt_type = RTN_MULTICAST;
1381 rth->rt_is_input= 1;
1382 rth->rt_iif = 0;
1383 rth->rt_pmtu = 0;
1384 rth->rt_gateway = 0;
1385 INIT_LIST_HEAD(&rth->rt_uncached);
1386 if (our) {
1387 rth->dst.input= ip_local_deliver;
1388 rth->rt_flags |= RTCF_LOCAL;
1389 }
1390
1391 #ifdef CONFIG_IP_MROUTE
1392 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1393 rth->dst.input = ip_mr_input;
1394 #endif
1395 RT_CACHE_STAT_INC(in_slow_mc);
1396
1397 skb_dst_set(skb, &rth->dst);
1398 return 0;
1399
1400 e_nobufs:
1401 return -ENOBUFS;
1402 e_inval:
1403 return -EINVAL;
1404 e_err:
1405 return err;
1406 }
1407
1408
1409 static void ip_handle_martian_source(struct net_device *dev,
1410 struct in_device *in_dev,
1411 struct sk_buff *skb,
1412 __be32 daddr,
1413 __be32 saddr)
1414 {
1415 RT_CACHE_STAT_INC(in_martian_src);
1416 #ifdef CONFIG_IP_ROUTE_VERBOSE
1417 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1418 /*
1419 * RFC1812 recommendation, if source is martian,
1420 * the only hint is MAC header.
1421 */
1422 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1423 &daddr, &saddr, dev->name);
1424 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1425 print_hex_dump(KERN_WARNING, "ll header: ",
1426 DUMP_PREFIX_OFFSET, 16, 1,
1427 skb_mac_header(skb),
1428 dev->hard_header_len, true);
1429 }
1430 }
1431 #endif
1432 }
1433
1434 /* called in rcu_read_lock() section */
1435 static int __mkroute_input(struct sk_buff *skb,
1436 const struct fib_result *res,
1437 struct in_device *in_dev,
1438 __be32 daddr, __be32 saddr, u32 tos)
1439 {
1440 struct rtable *rth;
1441 int err;
1442 struct in_device *out_dev;
1443 unsigned int flags = 0;
1444 bool do_cache;
1445 u32 itag;
1446
1447 /* get a working reference to the output device */
1448 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1449 if (out_dev == NULL) {
1450 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1451 return -EINVAL;
1452 }
1453
1454
1455 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1456 in_dev->dev, in_dev, &itag);
1457 if (err < 0) {
1458 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1459 saddr);
1460
1461 goto cleanup;
1462 }
1463
1464 if (out_dev == in_dev && err &&
1465 (IN_DEV_SHARED_MEDIA(out_dev) ||
1466 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1467 flags |= RTCF_DOREDIRECT;
1468
1469 if (skb->protocol != htons(ETH_P_IP)) {
1470 /* Not IP (i.e. ARP). Do not create route, if it is
1471 * invalid for proxy arp. DNAT routes are always valid.
1472 *
1473 * Proxy arp feature have been extended to allow, ARP
1474 * replies back to the same interface, to support
1475 * Private VLAN switch technologies. See arp.c.
1476 */
1477 if (out_dev == in_dev &&
1478 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1479 err = -EINVAL;
1480 goto cleanup;
1481 }
1482 }
1483
1484 do_cache = false;
1485 if (res->fi) {
1486 if (!itag) {
1487 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1488 if (rt_cache_valid(rth)) {
1489 skb_dst_set_noref(skb, &rth->dst);
1490 goto out;
1491 }
1492 do_cache = true;
1493 }
1494 }
1495
1496 rth = rt_dst_alloc(out_dev->dev,
1497 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1498 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1499 if (!rth) {
1500 err = -ENOBUFS;
1501 goto cleanup;
1502 }
1503
1504 rth->rt_genid = rt_genid(dev_net(rth->dst.dev));
1505 rth->rt_flags = flags;
1506 rth->rt_type = res->type;
1507 rth->rt_is_input = 1;
1508 rth->rt_iif = 0;
1509 rth->rt_pmtu = 0;
1510 rth->rt_gateway = 0;
1511 INIT_LIST_HEAD(&rth->rt_uncached);
1512
1513 rth->dst.input = ip_forward;
1514 rth->dst.output = ip_output;
1515
1516 rt_set_nexthop(rth, daddr, res, NULL, res->fi, res->type, itag);
1517 skb_dst_set(skb, &rth->dst);
1518 out:
1519 err = 0;
1520 cleanup:
1521 return err;
1522 }
1523
1524 static int ip_mkroute_input(struct sk_buff *skb,
1525 struct fib_result *res,
1526 const struct flowi4 *fl4,
1527 struct in_device *in_dev,
1528 __be32 daddr, __be32 saddr, u32 tos)
1529 {
1530 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1531 if (res->fi && res->fi->fib_nhs > 1)
1532 fib_select_multipath(res);
1533 #endif
1534
1535 /* create a routing cache entry */
1536 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1537 }
1538
1539 /*
1540 * NOTE. We drop all the packets that has local source
1541 * addresses, because every properly looped back packet
1542 * must have correct destination already attached by output routine.
1543 *
1544 * Such approach solves two big problems:
1545 * 1. Not simplex devices are handled properly.
1546 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1547 * called with rcu_read_lock()
1548 */
1549
1550 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1551 u8 tos, struct net_device *dev)
1552 {
1553 struct fib_result res;
1554 struct in_device *in_dev = __in_dev_get_rcu(dev);
1555 struct flowi4 fl4;
1556 unsigned int flags = 0;
1557 u32 itag = 0;
1558 struct rtable *rth;
1559 int err = -EINVAL;
1560 struct net *net = dev_net(dev);
1561 bool do_cache;
1562
1563 /* IP on this device is disabled. */
1564
1565 if (!in_dev)
1566 goto out;
1567
1568 /* Check for the most weird martians, which can be not detected
1569 by fib_lookup.
1570 */
1571
1572 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1573 goto martian_source;
1574
1575 res.fi = NULL;
1576 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1577 goto brd_input;
1578
1579 /* Accept zero addresses only to limited broadcast;
1580 * I even do not know to fix it or not. Waiting for complains :-)
1581 */
1582 if (ipv4_is_zeronet(saddr))
1583 goto martian_source;
1584
1585 if (ipv4_is_zeronet(daddr))
1586 goto martian_destination;
1587
1588 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) {
1589 if (ipv4_is_loopback(daddr))
1590 goto martian_destination;
1591
1592 if (ipv4_is_loopback(saddr))
1593 goto martian_source;
1594 }
1595
1596 /*
1597 * Now we are ready to route packet.
1598 */
1599 fl4.flowi4_oif = 0;
1600 fl4.flowi4_iif = dev->ifindex;
1601 fl4.flowi4_mark = skb->mark;
1602 fl4.flowi4_tos = tos;
1603 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1604 fl4.daddr = daddr;
1605 fl4.saddr = saddr;
1606 err = fib_lookup(net, &fl4, &res);
1607 if (err != 0)
1608 goto no_route;
1609
1610 RT_CACHE_STAT_INC(in_slow_tot);
1611
1612 if (res.type == RTN_BROADCAST)
1613 goto brd_input;
1614
1615 if (res.type == RTN_LOCAL) {
1616 err = fib_validate_source(skb, saddr, daddr, tos,
1617 net->loopback_dev->ifindex,
1618 dev, in_dev, &itag);
1619 if (err < 0)
1620 goto martian_source_keep_err;
1621 goto local_input;
1622 }
1623
1624 if (!IN_DEV_FORWARD(in_dev))
1625 goto no_route;
1626 if (res.type != RTN_UNICAST)
1627 goto martian_destination;
1628
1629 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1630 out: return err;
1631
1632 brd_input:
1633 if (skb->protocol != htons(ETH_P_IP))
1634 goto e_inval;
1635
1636 if (!ipv4_is_zeronet(saddr)) {
1637 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1638 in_dev, &itag);
1639 if (err < 0)
1640 goto martian_source_keep_err;
1641 }
1642 flags |= RTCF_BROADCAST;
1643 res.type = RTN_BROADCAST;
1644 RT_CACHE_STAT_INC(in_brd);
1645
1646 local_input:
1647 do_cache = false;
1648 if (res.fi) {
1649 if (!itag) {
1650 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1651 if (rt_cache_valid(rth)) {
1652 skb_dst_set_noref(skb, &rth->dst);
1653 err = 0;
1654 goto out;
1655 }
1656 do_cache = true;
1657 }
1658 }
1659
1660 rth = rt_dst_alloc(net->loopback_dev,
1661 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1662 if (!rth)
1663 goto e_nobufs;
1664
1665 rth->dst.input= ip_local_deliver;
1666 rth->dst.output= ip_rt_bug;
1667 #ifdef CONFIG_IP_ROUTE_CLASSID
1668 rth->dst.tclassid = itag;
1669 #endif
1670
1671 rth->rt_genid = rt_genid(net);
1672 rth->rt_flags = flags|RTCF_LOCAL;
1673 rth->rt_type = res.type;
1674 rth->rt_is_input = 1;
1675 rth->rt_iif = 0;
1676 rth->rt_pmtu = 0;
1677 rth->rt_gateway = 0;
1678 INIT_LIST_HEAD(&rth->rt_uncached);
1679 if (res.type == RTN_UNREACHABLE) {
1680 rth->dst.input= ip_error;
1681 rth->dst.error= -err;
1682 rth->rt_flags &= ~RTCF_LOCAL;
1683 }
1684 if (do_cache)
1685 rt_cache_route(&FIB_RES_NH(res), rth);
1686 skb_dst_set(skb, &rth->dst);
1687 err = 0;
1688 goto out;
1689
1690 no_route:
1691 RT_CACHE_STAT_INC(in_no_route);
1692 res.type = RTN_UNREACHABLE;
1693 if (err == -ESRCH)
1694 err = -ENETUNREACH;
1695 goto local_input;
1696
1697 /*
1698 * Do not cache martian addresses: they should be logged (RFC1812)
1699 */
1700 martian_destination:
1701 RT_CACHE_STAT_INC(in_martian_dst);
1702 #ifdef CONFIG_IP_ROUTE_VERBOSE
1703 if (IN_DEV_LOG_MARTIANS(in_dev))
1704 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1705 &daddr, &saddr, dev->name);
1706 #endif
1707
1708 e_inval:
1709 err = -EINVAL;
1710 goto out;
1711
1712 e_nobufs:
1713 err = -ENOBUFS;
1714 goto out;
1715
1716 martian_source:
1717 err = -EINVAL;
1718 martian_source_keep_err:
1719 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1720 goto out;
1721 }
1722
1723 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1724 u8 tos, struct net_device *dev)
1725 {
1726 int res;
1727
1728 rcu_read_lock();
1729
1730 /* Multicast recognition logic is moved from route cache to here.
1731 The problem was that too many Ethernet cards have broken/missing
1732 hardware multicast filters :-( As result the host on multicasting
1733 network acquires a lot of useless route cache entries, sort of
1734 SDR messages from all the world. Now we try to get rid of them.
1735 Really, provided software IP multicast filter is organized
1736 reasonably (at least, hashed), it does not result in a slowdown
1737 comparing with route cache reject entries.
1738 Note, that multicast routers are not affected, because
1739 route cache entry is created eventually.
1740 */
1741 if (ipv4_is_multicast(daddr)) {
1742 struct in_device *in_dev = __in_dev_get_rcu(dev);
1743
1744 if (in_dev) {
1745 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1746 ip_hdr(skb)->protocol);
1747 if (our
1748 #ifdef CONFIG_IP_MROUTE
1749 ||
1750 (!ipv4_is_local_multicast(daddr) &&
1751 IN_DEV_MFORWARD(in_dev))
1752 #endif
1753 ) {
1754 int res = ip_route_input_mc(skb, daddr, saddr,
1755 tos, dev, our);
1756 rcu_read_unlock();
1757 return res;
1758 }
1759 }
1760 rcu_read_unlock();
1761 return -EINVAL;
1762 }
1763 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1764 rcu_read_unlock();
1765 return res;
1766 }
1767 EXPORT_SYMBOL(ip_route_input_noref);
1768
1769 /* called with rcu_read_lock() */
1770 static struct rtable *__mkroute_output(const struct fib_result *res,
1771 const struct flowi4 *fl4, int orig_oif,
1772 struct net_device *dev_out,
1773 unsigned int flags)
1774 {
1775 struct fib_info *fi = res->fi;
1776 struct fib_nh_exception *fnhe;
1777 struct in_device *in_dev;
1778 u16 type = res->type;
1779 struct rtable *rth;
1780
1781 in_dev = __in_dev_get_rcu(dev_out);
1782 if (!in_dev)
1783 return ERR_PTR(-EINVAL);
1784
1785 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1786 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
1787 return ERR_PTR(-EINVAL);
1788
1789 if (ipv4_is_lbcast(fl4->daddr))
1790 type = RTN_BROADCAST;
1791 else if (ipv4_is_multicast(fl4->daddr))
1792 type = RTN_MULTICAST;
1793 else if (ipv4_is_zeronet(fl4->daddr))
1794 return ERR_PTR(-EINVAL);
1795
1796 if (dev_out->flags & IFF_LOOPBACK)
1797 flags |= RTCF_LOCAL;
1798
1799 if (type == RTN_BROADCAST) {
1800 flags |= RTCF_BROADCAST | RTCF_LOCAL;
1801 fi = NULL;
1802 } else if (type == RTN_MULTICAST) {
1803 flags |= RTCF_MULTICAST | RTCF_LOCAL;
1804 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
1805 fl4->flowi4_proto))
1806 flags &= ~RTCF_LOCAL;
1807 /* If multicast route do not exist use
1808 * default one, but do not gateway in this case.
1809 * Yes, it is hack.
1810 */
1811 if (fi && res->prefixlen < 4)
1812 fi = NULL;
1813 }
1814
1815 fnhe = NULL;
1816 if (fi) {
1817 struct rtable __rcu **prth;
1818
1819 fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);
1820 if (fnhe)
1821 prth = &fnhe->fnhe_rth;
1822 else
1823 prth = __this_cpu_ptr(FIB_RES_NH(*res).nh_pcpu_rth_output);
1824 rth = rcu_dereference(*prth);
1825 if (rt_cache_valid(rth)) {
1826 dst_hold(&rth->dst);
1827 return rth;
1828 }
1829 }
1830 rth = rt_dst_alloc(dev_out,
1831 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1832 IN_DEV_CONF_GET(in_dev, NOXFRM),
1833 fi);
1834 if (!rth)
1835 return ERR_PTR(-ENOBUFS);
1836
1837 rth->dst.output = ip_output;
1838
1839 rth->rt_genid = rt_genid(dev_net(dev_out));
1840 rth->rt_flags = flags;
1841 rth->rt_type = type;
1842 rth->rt_is_input = 0;
1843 rth->rt_iif = orig_oif ? : 0;
1844 rth->rt_pmtu = 0;
1845 rth->rt_gateway = 0;
1846 INIT_LIST_HEAD(&rth->rt_uncached);
1847
1848 RT_CACHE_STAT_INC(out_slow_tot);
1849
1850 if (flags & RTCF_LOCAL)
1851 rth->dst.input = ip_local_deliver;
1852 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1853 if (flags & RTCF_LOCAL &&
1854 !(dev_out->flags & IFF_LOOPBACK)) {
1855 rth->dst.output = ip_mc_output;
1856 RT_CACHE_STAT_INC(out_slow_mc);
1857 }
1858 #ifdef CONFIG_IP_MROUTE
1859 if (type == RTN_MULTICAST) {
1860 if (IN_DEV_MFORWARD(in_dev) &&
1861 !ipv4_is_local_multicast(fl4->daddr)) {
1862 rth->dst.input = ip_mr_input;
1863 rth->dst.output = ip_mc_output;
1864 }
1865 }
1866 #endif
1867 }
1868
1869 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
1870
1871 return rth;
1872 }
1873
1874 /*
1875 * Major route resolver routine.
1876 */
1877
1878 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
1879 {
1880 struct net_device *dev_out = NULL;
1881 __u8 tos = RT_FL_TOS(fl4);
1882 unsigned int flags = 0;
1883 struct fib_result res;
1884 struct rtable *rth;
1885 int orig_oif;
1886
1887 res.tclassid = 0;
1888 res.fi = NULL;
1889 res.table = NULL;
1890
1891 orig_oif = fl4->flowi4_oif;
1892
1893 fl4->flowi4_iif = net->loopback_dev->ifindex;
1894 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
1895 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
1896 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
1897
1898 rcu_read_lock();
1899 if (fl4->saddr) {
1900 rth = ERR_PTR(-EINVAL);
1901 if (ipv4_is_multicast(fl4->saddr) ||
1902 ipv4_is_lbcast(fl4->saddr) ||
1903 ipv4_is_zeronet(fl4->saddr))
1904 goto out;
1905
1906 /* I removed check for oif == dev_out->oif here.
1907 It was wrong for two reasons:
1908 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
1909 is assigned to multiple interfaces.
1910 2. Moreover, we are allowed to send packets with saddr
1911 of another iface. --ANK
1912 */
1913
1914 if (fl4->flowi4_oif == 0 &&
1915 (ipv4_is_multicast(fl4->daddr) ||
1916 ipv4_is_lbcast(fl4->daddr))) {
1917 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1918 dev_out = __ip_dev_find(net, fl4->saddr, false);
1919 if (dev_out == NULL)
1920 goto out;
1921
1922 /* Special hack: user can direct multicasts
1923 and limited broadcast via necessary interface
1924 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
1925 This hack is not just for fun, it allows
1926 vic,vat and friends to work.
1927 They bind socket to loopback, set ttl to zero
1928 and expect that it will work.
1929 From the viewpoint of routing cache they are broken,
1930 because we are not allowed to build multicast path
1931 with loopback source addr (look, routing cache
1932 cannot know, that ttl is zero, so that packet
1933 will not leave this host and route is valid).
1934 Luckily, this hack is good workaround.
1935 */
1936
1937 fl4->flowi4_oif = dev_out->ifindex;
1938 goto make_route;
1939 }
1940
1941 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
1942 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
1943 if (!__ip_dev_find(net, fl4->saddr, false))
1944 goto out;
1945 }
1946 }
1947
1948
1949 if (fl4->flowi4_oif) {
1950 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
1951 rth = ERR_PTR(-ENODEV);
1952 if (dev_out == NULL)
1953 goto out;
1954
1955 /* RACE: Check return value of inet_select_addr instead. */
1956 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
1957 rth = ERR_PTR(-ENETUNREACH);
1958 goto out;
1959 }
1960 if (ipv4_is_local_multicast(fl4->daddr) ||
1961 ipv4_is_lbcast(fl4->daddr)) {
1962 if (!fl4->saddr)
1963 fl4->saddr = inet_select_addr(dev_out, 0,
1964 RT_SCOPE_LINK);
1965 goto make_route;
1966 }
1967 if (fl4->saddr) {
1968 if (ipv4_is_multicast(fl4->daddr))
1969 fl4->saddr = inet_select_addr(dev_out, 0,
1970 fl4->flowi4_scope);
1971 else if (!fl4->daddr)
1972 fl4->saddr = inet_select_addr(dev_out, 0,
1973 RT_SCOPE_HOST);
1974 }
1975 }
1976
1977 if (!fl4->daddr) {
1978 fl4->daddr = fl4->saddr;
1979 if (!fl4->daddr)
1980 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
1981 dev_out = net->loopback_dev;
1982 fl4->flowi4_oif = net->loopback_dev->ifindex;
1983 res.type = RTN_LOCAL;
1984 flags |= RTCF_LOCAL;
1985 goto make_route;
1986 }
1987
1988 if (fib_lookup(net, fl4, &res)) {
1989 res.fi = NULL;
1990 res.table = NULL;
1991 if (fl4->flowi4_oif) {
1992 /* Apparently, routing tables are wrong. Assume,
1993 that the destination is on link.
1994
1995 WHY? DW.
1996 Because we are allowed to send to iface
1997 even if it has NO routes and NO assigned
1998 addresses. When oif is specified, routing
1999 tables are looked up with only one purpose:
2000 to catch if destination is gatewayed, rather than
2001 direct. Moreover, if MSG_DONTROUTE is set,
2002 we send packet, ignoring both routing tables
2003 and ifaddr state. --ANK
2004
2005
2006 We could make it even if oif is unknown,
2007 likely IPv6, but we do not.
2008 */
2009
2010 if (fl4->saddr == 0)
2011 fl4->saddr = inet_select_addr(dev_out, 0,
2012 RT_SCOPE_LINK);
2013 res.type = RTN_UNICAST;
2014 goto make_route;
2015 }
2016 rth = ERR_PTR(-ENETUNREACH);
2017 goto out;
2018 }
2019
2020 if (res.type == RTN_LOCAL) {
2021 if (!fl4->saddr) {
2022 if (res.fi->fib_prefsrc)
2023 fl4->saddr = res.fi->fib_prefsrc;
2024 else
2025 fl4->saddr = fl4->daddr;
2026 }
2027 dev_out = net->loopback_dev;
2028 fl4->flowi4_oif = dev_out->ifindex;
2029 flags |= RTCF_LOCAL;
2030 goto make_route;
2031 }
2032
2033 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2034 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2035 fib_select_multipath(&res);
2036 else
2037 #endif
2038 if (!res.prefixlen &&
2039 res.table->tb_num_default > 1 &&
2040 res.type == RTN_UNICAST && !fl4->flowi4_oif)
2041 fib_select_default(&res);
2042
2043 if (!fl4->saddr)
2044 fl4->saddr = FIB_RES_PREFSRC(net, res);
2045
2046 dev_out = FIB_RES_DEV(res);
2047 fl4->flowi4_oif = dev_out->ifindex;
2048
2049
2050 make_route:
2051 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2052
2053 out:
2054 rcu_read_unlock();
2055 return rth;
2056 }
2057 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2058
2059 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2060 {
2061 return NULL;
2062 }
2063
2064 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2065 {
2066 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2067
2068 return mtu ? : dst->dev->mtu;
2069 }
2070
2071 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2072 struct sk_buff *skb, u32 mtu)
2073 {
2074 }
2075
2076 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2077 struct sk_buff *skb)
2078 {
2079 }
2080
2081 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2082 unsigned long old)
2083 {
2084 return NULL;
2085 }
2086
2087 static struct dst_ops ipv4_dst_blackhole_ops = {
2088 .family = AF_INET,
2089 .protocol = cpu_to_be16(ETH_P_IP),
2090 .check = ipv4_blackhole_dst_check,
2091 .mtu = ipv4_blackhole_mtu,
2092 .default_advmss = ipv4_default_advmss,
2093 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2094 .redirect = ipv4_rt_blackhole_redirect,
2095 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2096 .neigh_lookup = ipv4_neigh_lookup,
2097 };
2098
2099 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2100 {
2101 struct rtable *ort = (struct rtable *) dst_orig;
2102 struct rtable *rt;
2103
2104 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2105 if (rt) {
2106 struct dst_entry *new = &rt->dst;
2107
2108 new->__use = 1;
2109 new->input = dst_discard;
2110 new->output = dst_discard;
2111
2112 new->dev = ort->dst.dev;
2113 if (new->dev)
2114 dev_hold(new->dev);
2115
2116 rt->rt_is_input = ort->rt_is_input;
2117 rt->rt_iif = ort->rt_iif;
2118 rt->rt_pmtu = ort->rt_pmtu;
2119
2120 rt->rt_genid = rt_genid(net);
2121 rt->rt_flags = ort->rt_flags;
2122 rt->rt_type = ort->rt_type;
2123 rt->rt_gateway = ort->rt_gateway;
2124
2125 INIT_LIST_HEAD(&rt->rt_uncached);
2126
2127 dst_free(new);
2128 }
2129
2130 dst_release(dst_orig);
2131
2132 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2133 }
2134
2135 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2136 struct sock *sk)
2137 {
2138 struct rtable *rt = __ip_route_output_key(net, flp4);
2139
2140 if (IS_ERR(rt))
2141 return rt;
2142
2143 if (flp4->flowi4_proto)
2144 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2145 flowi4_to_flowi(flp4),
2146 sk, 0);
2147
2148 return rt;
2149 }
2150 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2151
2152 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2153 struct flowi4 *fl4, struct sk_buff *skb, u32 pid,
2154 u32 seq, int event, int nowait, unsigned int flags)
2155 {
2156 struct rtable *rt = skb_rtable(skb);
2157 struct rtmsg *r;
2158 struct nlmsghdr *nlh;
2159 unsigned long expires = 0;
2160 u32 error;
2161 u32 metrics[RTAX_MAX];
2162
2163 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
2164 if (nlh == NULL)
2165 return -EMSGSIZE;
2166
2167 r = nlmsg_data(nlh);
2168 r->rtm_family = AF_INET;
2169 r->rtm_dst_len = 32;
2170 r->rtm_src_len = 0;
2171 r->rtm_tos = fl4->flowi4_tos;
2172 r->rtm_table = RT_TABLE_MAIN;
2173 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2174 goto nla_put_failure;
2175 r->rtm_type = rt->rt_type;
2176 r->rtm_scope = RT_SCOPE_UNIVERSE;
2177 r->rtm_protocol = RTPROT_UNSPEC;
2178 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2179 if (rt->rt_flags & RTCF_NOTIFY)
2180 r->rtm_flags |= RTM_F_NOTIFY;
2181
2182 if (nla_put_be32(skb, RTA_DST, dst))
2183 goto nla_put_failure;
2184 if (src) {
2185 r->rtm_src_len = 32;
2186 if (nla_put_be32(skb, RTA_SRC, src))
2187 goto nla_put_failure;
2188 }
2189 if (rt->dst.dev &&
2190 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2191 goto nla_put_failure;
2192 #ifdef CONFIG_IP_ROUTE_CLASSID
2193 if (rt->dst.tclassid &&
2194 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2195 goto nla_put_failure;
2196 #endif
2197 if (!rt_is_input_route(rt) &&
2198 fl4->saddr != src) {
2199 if (nla_put_be32(skb, RTA_PREFSRC, fl4->saddr))
2200 goto nla_put_failure;
2201 }
2202 if (rt->rt_gateway &&
2203 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2204 goto nla_put_failure;
2205
2206 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2207 if (rt->rt_pmtu)
2208 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2209 if (rtnetlink_put_metrics(skb, metrics) < 0)
2210 goto nla_put_failure;
2211
2212 if (fl4->flowi4_mark &&
2213 nla_put_be32(skb, RTA_MARK, fl4->flowi4_mark))
2214 goto nla_put_failure;
2215
2216 error = rt->dst.error;
2217 expires = rt->dst.expires;
2218 if (expires) {
2219 if (time_before(jiffies, expires))
2220 expires -= jiffies;
2221 else
2222 expires = 0;
2223 }
2224
2225 if (rt_is_input_route(rt)) {
2226 if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))
2227 goto nla_put_failure;
2228 }
2229
2230 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2231 goto nla_put_failure;
2232
2233 return nlmsg_end(skb, nlh);
2234
2235 nla_put_failure:
2236 nlmsg_cancel(skb, nlh);
2237 return -EMSGSIZE;
2238 }
2239
2240 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
2241 {
2242 struct net *net = sock_net(in_skb->sk);
2243 struct rtmsg *rtm;
2244 struct nlattr *tb[RTA_MAX+1];
2245 struct rtable *rt = NULL;
2246 struct flowi4 fl4;
2247 __be32 dst = 0;
2248 __be32 src = 0;
2249 u32 iif;
2250 int err;
2251 int mark;
2252 struct sk_buff *skb;
2253
2254 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2255 if (err < 0)
2256 goto errout;
2257
2258 rtm = nlmsg_data(nlh);
2259
2260 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2261 if (skb == NULL) {
2262 err = -ENOBUFS;
2263 goto errout;
2264 }
2265
2266 /* Reserve room for dummy headers, this skb can pass
2267 through good chunk of routing engine.
2268 */
2269 skb_reset_mac_header(skb);
2270 skb_reset_network_header(skb);
2271
2272 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2273 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2274 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2275
2276 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2277 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2278 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2279 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2280
2281 memset(&fl4, 0, sizeof(fl4));
2282 fl4.daddr = dst;
2283 fl4.saddr = src;
2284 fl4.flowi4_tos = rtm->rtm_tos;
2285 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2286 fl4.flowi4_mark = mark;
2287
2288 if (iif) {
2289 struct net_device *dev;
2290
2291 dev = __dev_get_by_index(net, iif);
2292 if (dev == NULL) {
2293 err = -ENODEV;
2294 goto errout_free;
2295 }
2296
2297 skb->protocol = htons(ETH_P_IP);
2298 skb->dev = dev;
2299 skb->mark = mark;
2300 local_bh_disable();
2301 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2302 local_bh_enable();
2303
2304 rt = skb_rtable(skb);
2305 if (err == 0 && rt->dst.error)
2306 err = -rt->dst.error;
2307 } else {
2308 rt = ip_route_output_key(net, &fl4);
2309
2310 err = 0;
2311 if (IS_ERR(rt))
2312 err = PTR_ERR(rt);
2313 }
2314
2315 if (err)
2316 goto errout_free;
2317
2318 skb_dst_set(skb, &rt->dst);
2319 if (rtm->rtm_flags & RTM_F_NOTIFY)
2320 rt->rt_flags |= RTCF_NOTIFY;
2321
2322 err = rt_fill_info(net, dst, src, &fl4, skb,
2323 NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
2324 RTM_NEWROUTE, 0, 0);
2325 if (err <= 0)
2326 goto errout_free;
2327
2328 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).pid);
2329 errout:
2330 return err;
2331
2332 errout_free:
2333 kfree_skb(skb);
2334 goto errout;
2335 }
2336
2337 int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb)
2338 {
2339 return skb->len;
2340 }
2341
2342 void ip_rt_multicast_event(struct in_device *in_dev)
2343 {
2344 rt_cache_flush(dev_net(in_dev->dev));
2345 }
2346
2347 #ifdef CONFIG_SYSCTL
2348 static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,
2349 void __user *buffer,
2350 size_t *lenp, loff_t *ppos)
2351 {
2352 if (write) {
2353 rt_cache_flush((struct net *)__ctl->extra1);
2354 return 0;
2355 }
2356
2357 return -EINVAL;
2358 }
2359
2360 static ctl_table ipv4_route_table[] = {
2361 {
2362 .procname = "gc_thresh",
2363 .data = &ipv4_dst_ops.gc_thresh,
2364 .maxlen = sizeof(int),
2365 .mode = 0644,
2366 .proc_handler = proc_dointvec,
2367 },
2368 {
2369 .procname = "max_size",
2370 .data = &ip_rt_max_size,
2371 .maxlen = sizeof(int),
2372 .mode = 0644,
2373 .proc_handler = proc_dointvec,
2374 },
2375 {
2376 /* Deprecated. Use gc_min_interval_ms */
2377
2378 .procname = "gc_min_interval",
2379 .data = &ip_rt_gc_min_interval,
2380 .maxlen = sizeof(int),
2381 .mode = 0644,
2382 .proc_handler = proc_dointvec_jiffies,
2383 },
2384 {
2385 .procname = "gc_min_interval_ms",
2386 .data = &ip_rt_gc_min_interval,
2387 .maxlen = sizeof(int),
2388 .mode = 0644,
2389 .proc_handler = proc_dointvec_ms_jiffies,
2390 },
2391 {
2392 .procname = "gc_timeout",
2393 .data = &ip_rt_gc_timeout,
2394 .maxlen = sizeof(int),
2395 .mode = 0644,
2396 .proc_handler = proc_dointvec_jiffies,
2397 },
2398 {
2399 .procname = "gc_interval",
2400 .data = &ip_rt_gc_interval,
2401 .maxlen = sizeof(int),
2402 .mode = 0644,
2403 .proc_handler = proc_dointvec_jiffies,
2404 },
2405 {
2406 .procname = "redirect_load",
2407 .data = &ip_rt_redirect_load,
2408 .maxlen = sizeof(int),
2409 .mode = 0644,
2410 .proc_handler = proc_dointvec,
2411 },
2412 {
2413 .procname = "redirect_number",
2414 .data = &ip_rt_redirect_number,
2415 .maxlen = sizeof(int),
2416 .mode = 0644,
2417 .proc_handler = proc_dointvec,
2418 },
2419 {
2420 .procname = "redirect_silence",
2421 .data = &ip_rt_redirect_silence,
2422 .maxlen = sizeof(int),
2423 .mode = 0644,
2424 .proc_handler = proc_dointvec,
2425 },
2426 {
2427 .procname = "error_cost",
2428 .data = &ip_rt_error_cost,
2429 .maxlen = sizeof(int),
2430 .mode = 0644,
2431 .proc_handler = proc_dointvec,
2432 },
2433 {
2434 .procname = "error_burst",
2435 .data = &ip_rt_error_burst,
2436 .maxlen = sizeof(int),
2437 .mode = 0644,
2438 .proc_handler = proc_dointvec,
2439 },
2440 {
2441 .procname = "gc_elasticity",
2442 .data = &ip_rt_gc_elasticity,
2443 .maxlen = sizeof(int),
2444 .mode = 0644,
2445 .proc_handler = proc_dointvec,
2446 },
2447 {
2448 .procname = "mtu_expires",
2449 .data = &ip_rt_mtu_expires,
2450 .maxlen = sizeof(int),
2451 .mode = 0644,
2452 .proc_handler = proc_dointvec_jiffies,
2453 },
2454 {
2455 .procname = "min_pmtu",
2456 .data = &ip_rt_min_pmtu,
2457 .maxlen = sizeof(int),
2458 .mode = 0644,
2459 .proc_handler = proc_dointvec,
2460 },
2461 {
2462 .procname = "min_adv_mss",
2463 .data = &ip_rt_min_advmss,
2464 .maxlen = sizeof(int),
2465 .mode = 0644,
2466 .proc_handler = proc_dointvec,
2467 },
2468 { }
2469 };
2470
2471 static struct ctl_table ipv4_route_flush_table[] = {
2472 {
2473 .procname = "flush",
2474 .maxlen = sizeof(int),
2475 .mode = 0200,
2476 .proc_handler = ipv4_sysctl_rtcache_flush,
2477 },
2478 { },
2479 };
2480
2481 static __net_init int sysctl_route_net_init(struct net *net)
2482 {
2483 struct ctl_table *tbl;
2484
2485 tbl = ipv4_route_flush_table;
2486 if (!net_eq(net, &init_net)) {
2487 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2488 if (tbl == NULL)
2489 goto err_dup;
2490 }
2491 tbl[0].extra1 = net;
2492
2493 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2494 if (net->ipv4.route_hdr == NULL)
2495 goto err_reg;
2496 return 0;
2497
2498 err_reg:
2499 if (tbl != ipv4_route_flush_table)
2500 kfree(tbl);
2501 err_dup:
2502 return -ENOMEM;
2503 }
2504
2505 static __net_exit void sysctl_route_net_exit(struct net *net)
2506 {
2507 struct ctl_table *tbl;
2508
2509 tbl = net->ipv4.route_hdr->ctl_table_arg;
2510 unregister_net_sysctl_table(net->ipv4.route_hdr);
2511 BUG_ON(tbl == ipv4_route_flush_table);
2512 kfree(tbl);
2513 }
2514
2515 static __net_initdata struct pernet_operations sysctl_route_ops = {
2516 .init = sysctl_route_net_init,
2517 .exit = sysctl_route_net_exit,
2518 };
2519 #endif
2520
2521 static __net_init int rt_genid_init(struct net *net)
2522 {
2523 get_random_bytes(&net->ipv4.rt_genid,
2524 sizeof(net->ipv4.rt_genid));
2525 get_random_bytes(&net->ipv4.dev_addr_genid,
2526 sizeof(net->ipv4.dev_addr_genid));
2527 return 0;
2528 }
2529
2530 static __net_initdata struct pernet_operations rt_genid_ops = {
2531 .init = rt_genid_init,
2532 };
2533
2534 static int __net_init ipv4_inetpeer_init(struct net *net)
2535 {
2536 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2537
2538 if (!bp)
2539 return -ENOMEM;
2540 inet_peer_base_init(bp);
2541 net->ipv4.peers = bp;
2542 return 0;
2543 }
2544
2545 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2546 {
2547 struct inet_peer_base *bp = net->ipv4.peers;
2548
2549 net->ipv4.peers = NULL;
2550 inetpeer_invalidate_tree(bp);
2551 kfree(bp);
2552 }
2553
2554 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2555 .init = ipv4_inetpeer_init,
2556 .exit = ipv4_inetpeer_exit,
2557 };
2558
2559 #ifdef CONFIG_IP_ROUTE_CLASSID
2560 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2561 #endif /* CONFIG_IP_ROUTE_CLASSID */
2562
2563 int __init ip_rt_init(void)
2564 {
2565 int rc = 0;
2566
2567 #ifdef CONFIG_IP_ROUTE_CLASSID
2568 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2569 if (!ip_rt_acct)
2570 panic("IP: failed to allocate ip_rt_acct\n");
2571 #endif
2572
2573 ipv4_dst_ops.kmem_cachep =
2574 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2575 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2576
2577 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2578
2579 if (dst_entries_init(&ipv4_dst_ops) < 0)
2580 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2581
2582 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2583 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2584
2585 ipv4_dst_ops.gc_thresh = ~0;
2586 ip_rt_max_size = INT_MAX;
2587
2588 devinet_init();
2589 ip_fib_init();
2590
2591 if (ip_rt_proc_init())
2592 pr_err("Unable to create route proc files\n");
2593 #ifdef CONFIG_XFRM
2594 xfrm_init();
2595 xfrm4_init(ip_rt_max_size);
2596 #endif
2597 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2598
2599 #ifdef CONFIG_SYSCTL
2600 register_pernet_subsys(&sysctl_route_ops);
2601 #endif
2602 register_pernet_subsys(&rt_genid_ops);
2603 register_pernet_subsys(&ipv4_inetpeer_ops);
2604 return rc;
2605 }
2606
2607 #ifdef CONFIG_SYSCTL
2608 /*
2609 * We really need to sanitize the damn ipv4 init order, then all
2610 * this nonsense will go away.
2611 */
2612 void __init ip_static_sysctl_init(void)
2613 {
2614 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2615 }
2616 #endif
Linus' kernel tree