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[mirror_ubuntu-artful-kernel.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 <linux/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 <linux/jhash.h>
93 #include <net/dst.h>
94 #include <net/dst_metadata.h>
95 #include <net/net_namespace.h>
96 #include <net/protocol.h>
97 #include <net/ip.h>
98 #include <net/route.h>
99 #include <net/inetpeer.h>
100 #include <net/sock.h>
101 #include <net/ip_fib.h>
102 #include <net/arp.h>
103 #include <net/tcp.h>
104 #include <net/icmp.h>
105 #include <net/xfrm.h>
106 #include <net/lwtunnel.h>
107 #include <net/netevent.h>
108 #include <net/rtnetlink.h>
109 #ifdef CONFIG_SYSCTL
110 #include <linux/sysctl.h>
111 #include <linux/kmemleak.h>
112 #endif
113 #include <net/secure_seq.h>
114 #include <net/ip_tunnels.h>
115 #include <net/l3mdev.h>
116
117 #define RT_FL_TOS(oldflp4) \
118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
119
120 #define RT_GC_TIMEOUT (300*HZ)
121
122 static int ip_rt_max_size;
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_mtu_expires __read_mostly = 10 * 60 * HZ;
129 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
130 static int ip_rt_min_advmss __read_mostly = 256;
131
132 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
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 u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
149 {
150 WARN_ON(1);
151 return NULL;
152 }
153
154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
155 struct sk_buff *skb,
156 const void *daddr);
157 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
158
159 static struct dst_ops ipv4_dst_ops = {
160 .family = AF_INET,
161 .check = ipv4_dst_check,
162 .default_advmss = ipv4_default_advmss,
163 .mtu = ipv4_mtu,
164 .cow_metrics = ipv4_cow_metrics,
165 .destroy = ipv4_dst_destroy,
166 .negative_advice = ipv4_negative_advice,
167 .link_failure = ipv4_link_failure,
168 .update_pmtu = ip_rt_update_pmtu,
169 .redirect = ip_do_redirect,
170 .local_out = __ip_local_out,
171 .neigh_lookup = ipv4_neigh_lookup,
172 .confirm_neigh = ipv4_confirm_neigh,
173 };
174
175 #define ECN_OR_COST(class) TC_PRIO_##class
176
177 const __u8 ip_tos2prio[16] = {
178 TC_PRIO_BESTEFFORT,
179 ECN_OR_COST(BESTEFFORT),
180 TC_PRIO_BESTEFFORT,
181 ECN_OR_COST(BESTEFFORT),
182 TC_PRIO_BULK,
183 ECN_OR_COST(BULK),
184 TC_PRIO_BULK,
185 ECN_OR_COST(BULK),
186 TC_PRIO_INTERACTIVE,
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE,
189 ECN_OR_COST(INTERACTIVE),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK),
192 TC_PRIO_INTERACTIVE_BULK,
193 ECN_OR_COST(INTERACTIVE_BULK)
194 };
195 EXPORT_SYMBOL(ip_tos2prio);
196
197 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
198 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
199
200 #ifdef CONFIG_PROC_FS
201 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
202 {
203 if (*pos)
204 return NULL;
205 return SEQ_START_TOKEN;
206 }
207
208 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
209 {
210 ++*pos;
211 return NULL;
212 }
213
214 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
215 {
216 }
217
218 static int rt_cache_seq_show(struct seq_file *seq, void *v)
219 {
220 if (v == SEQ_START_TOKEN)
221 seq_printf(seq, "%-127s\n",
222 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
223 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
224 "HHUptod\tSpecDst");
225 return 0;
226 }
227
228 static const struct seq_operations rt_cache_seq_ops = {
229 .start = rt_cache_seq_start,
230 .next = rt_cache_seq_next,
231 .stop = rt_cache_seq_stop,
232 .show = rt_cache_seq_show,
233 };
234
235 static int rt_cache_seq_open(struct inode *inode, struct file *file)
236 {
237 return seq_open(file, &rt_cache_seq_ops);
238 }
239
240 static const struct file_operations rt_cache_seq_fops = {
241 .owner = THIS_MODULE,
242 .open = rt_cache_seq_open,
243 .read = seq_read,
244 .llseek = seq_lseek,
245 .release = seq_release,
246 };
247
248
249 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
250 {
251 int cpu;
252
253 if (*pos == 0)
254 return SEQ_START_TOKEN;
255
256 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
257 if (!cpu_possible(cpu))
258 continue;
259 *pos = cpu+1;
260 return &per_cpu(rt_cache_stat, cpu);
261 }
262 return NULL;
263 }
264
265 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
266 {
267 int cpu;
268
269 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
270 if (!cpu_possible(cpu))
271 continue;
272 *pos = cpu+1;
273 return &per_cpu(rt_cache_stat, cpu);
274 }
275 return NULL;
276
277 }
278
279 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
280 {
281
282 }
283
284 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
285 {
286 struct rt_cache_stat *st = v;
287
288 if (v == SEQ_START_TOKEN) {
289 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");
290 return 0;
291 }
292
293 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
294 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
295 dst_entries_get_slow(&ipv4_dst_ops),
296 0, /* st->in_hit */
297 st->in_slow_tot,
298 st->in_slow_mc,
299 st->in_no_route,
300 st->in_brd,
301 st->in_martian_dst,
302 st->in_martian_src,
303
304 0, /* st->out_hit */
305 st->out_slow_tot,
306 st->out_slow_mc,
307
308 0, /* st->gc_total */
309 0, /* st->gc_ignored */
310 0, /* st->gc_goal_miss */
311 0, /* st->gc_dst_overflow */
312 0, /* st->in_hlist_search */
313 0 /* st->out_hlist_search */
314 );
315 return 0;
316 }
317
318 static const struct seq_operations rt_cpu_seq_ops = {
319 .start = rt_cpu_seq_start,
320 .next = rt_cpu_seq_next,
321 .stop = rt_cpu_seq_stop,
322 .show = rt_cpu_seq_show,
323 };
324
325
326 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
327 {
328 return seq_open(file, &rt_cpu_seq_ops);
329 }
330
331 static const struct file_operations rt_cpu_seq_fops = {
332 .owner = THIS_MODULE,
333 .open = rt_cpu_seq_open,
334 .read = seq_read,
335 .llseek = seq_lseek,
336 .release = seq_release,
337 };
338
339 #ifdef CONFIG_IP_ROUTE_CLASSID
340 static int rt_acct_proc_show(struct seq_file *m, void *v)
341 {
342 struct ip_rt_acct *dst, *src;
343 unsigned int i, j;
344
345 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
346 if (!dst)
347 return -ENOMEM;
348
349 for_each_possible_cpu(i) {
350 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
351 for (j = 0; j < 256; j++) {
352 dst[j].o_bytes += src[j].o_bytes;
353 dst[j].o_packets += src[j].o_packets;
354 dst[j].i_bytes += src[j].i_bytes;
355 dst[j].i_packets += src[j].i_packets;
356 }
357 }
358
359 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
360 kfree(dst);
361 return 0;
362 }
363
364 static int rt_acct_proc_open(struct inode *inode, struct file *file)
365 {
366 return single_open(file, rt_acct_proc_show, NULL);
367 }
368
369 static const struct file_operations rt_acct_proc_fops = {
370 .owner = THIS_MODULE,
371 .open = rt_acct_proc_open,
372 .read = seq_read,
373 .llseek = seq_lseek,
374 .release = single_release,
375 };
376 #endif
377
378 static int __net_init ip_rt_do_proc_init(struct net *net)
379 {
380 struct proc_dir_entry *pde;
381
382 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
383 &rt_cache_seq_fops);
384 if (!pde)
385 goto err1;
386
387 pde = proc_create("rt_cache", S_IRUGO,
388 net->proc_net_stat, &rt_cpu_seq_fops);
389 if (!pde)
390 goto err2;
391
392 #ifdef CONFIG_IP_ROUTE_CLASSID
393 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
394 if (!pde)
395 goto err3;
396 #endif
397 return 0;
398
399 #ifdef CONFIG_IP_ROUTE_CLASSID
400 err3:
401 remove_proc_entry("rt_cache", net->proc_net_stat);
402 #endif
403 err2:
404 remove_proc_entry("rt_cache", net->proc_net);
405 err1:
406 return -ENOMEM;
407 }
408
409 static void __net_exit ip_rt_do_proc_exit(struct net *net)
410 {
411 remove_proc_entry("rt_cache", net->proc_net_stat);
412 remove_proc_entry("rt_cache", net->proc_net);
413 #ifdef CONFIG_IP_ROUTE_CLASSID
414 remove_proc_entry("rt_acct", net->proc_net);
415 #endif
416 }
417
418 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
419 .init = ip_rt_do_proc_init,
420 .exit = ip_rt_do_proc_exit,
421 };
422
423 static int __init ip_rt_proc_init(void)
424 {
425 return register_pernet_subsys(&ip_rt_proc_ops);
426 }
427
428 #else
429 static inline int ip_rt_proc_init(void)
430 {
431 return 0;
432 }
433 #endif /* CONFIG_PROC_FS */
434
435 static inline bool rt_is_expired(const struct rtable *rth)
436 {
437 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
438 }
439
440 void rt_cache_flush(struct net *net)
441 {
442 rt_genid_bump_ipv4(net);
443 }
444
445 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
446 struct sk_buff *skb,
447 const void *daddr)
448 {
449 struct net_device *dev = dst->dev;
450 const __be32 *pkey = daddr;
451 const struct rtable *rt;
452 struct neighbour *n;
453
454 rt = (const struct rtable *) dst;
455 if (rt->rt_gateway)
456 pkey = (const __be32 *) &rt->rt_gateway;
457 else if (skb)
458 pkey = &ip_hdr(skb)->daddr;
459
460 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
461 if (n)
462 return n;
463 return neigh_create(&arp_tbl, pkey, dev);
464 }
465
466 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
467 {
468 struct net_device *dev = dst->dev;
469 const __be32 *pkey = daddr;
470 const struct rtable *rt;
471
472 rt = (const struct rtable *)dst;
473 if (rt->rt_gateway)
474 pkey = (const __be32 *)&rt->rt_gateway;
475 else if (!daddr ||
476 (rt->rt_flags &
477 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
478 return;
479
480 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
481 }
482
483 #define IP_IDENTS_SZ 2048u
484
485 static atomic_t *ip_idents __read_mostly;
486 static u32 *ip_tstamps __read_mostly;
487
488 /* In order to protect privacy, we add a perturbation to identifiers
489 * if one generator is seldom used. This makes hard for an attacker
490 * to infer how many packets were sent between two points in time.
491 */
492 u32 ip_idents_reserve(u32 hash, int segs)
493 {
494 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
495 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
496 u32 old = ACCESS_ONCE(*p_tstamp);
497 u32 now = (u32)jiffies;
498 u32 new, delta = 0;
499
500 if (old != now && cmpxchg(p_tstamp, old, now) == old)
501 delta = prandom_u32_max(now - old);
502
503 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
504 do {
505 old = (u32)atomic_read(p_id);
506 new = old + delta + segs;
507 } while (atomic_cmpxchg(p_id, old, new) != old);
508
509 return new - segs;
510 }
511 EXPORT_SYMBOL(ip_idents_reserve);
512
513 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
514 {
515 static u32 ip_idents_hashrnd __read_mostly;
516 u32 hash, id;
517
518 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
519
520 hash = jhash_3words((__force u32)iph->daddr,
521 (__force u32)iph->saddr,
522 iph->protocol ^ net_hash_mix(net),
523 ip_idents_hashrnd);
524 id = ip_idents_reserve(hash, segs);
525 iph->id = htons(id);
526 }
527 EXPORT_SYMBOL(__ip_select_ident);
528
529 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
530 const struct sock *sk,
531 const struct iphdr *iph,
532 int oif, u8 tos,
533 u8 prot, u32 mark, int flow_flags)
534 {
535 if (sk) {
536 const struct inet_sock *inet = inet_sk(sk);
537
538 oif = sk->sk_bound_dev_if;
539 mark = sk->sk_mark;
540 tos = RT_CONN_FLAGS(sk);
541 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
542 }
543 flowi4_init_output(fl4, oif, mark, tos,
544 RT_SCOPE_UNIVERSE, prot,
545 flow_flags,
546 iph->daddr, iph->saddr, 0, 0,
547 sock_net_uid(net, sk));
548 }
549
550 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
551 const struct sock *sk)
552 {
553 const struct net *net = dev_net(skb->dev);
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(net, 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, sk->sk_uid);
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 inline void rt_free(struct rtable *rt)
591 {
592 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
593 }
594
595 static DEFINE_SPINLOCK(fnhe_lock);
596
597 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
598 {
599 struct rtable *rt;
600
601 rt = rcu_dereference(fnhe->fnhe_rth_input);
602 if (rt) {
603 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
604 rt_free(rt);
605 }
606 rt = rcu_dereference(fnhe->fnhe_rth_output);
607 if (rt) {
608 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
609 rt_free(rt);
610 }
611 }
612
613 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
614 {
615 struct fib_nh_exception *fnhe, *oldest;
616
617 oldest = rcu_dereference(hash->chain);
618 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
619 fnhe = rcu_dereference(fnhe->fnhe_next)) {
620 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
621 oldest = fnhe;
622 }
623 fnhe_flush_routes(oldest);
624 return oldest;
625 }
626
627 static inline u32 fnhe_hashfun(__be32 daddr)
628 {
629 static u32 fnhe_hashrnd __read_mostly;
630 u32 hval;
631
632 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
633 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
634 return hash_32(hval, FNHE_HASH_SHIFT);
635 }
636
637 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
638 {
639 rt->rt_pmtu = fnhe->fnhe_pmtu;
640 rt->dst.expires = fnhe->fnhe_expires;
641
642 if (fnhe->fnhe_gw) {
643 rt->rt_flags |= RTCF_REDIRECTED;
644 rt->rt_gateway = fnhe->fnhe_gw;
645 rt->rt_uses_gateway = 1;
646 }
647 }
648
649 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
650 u32 pmtu, unsigned long expires)
651 {
652 struct fnhe_hash_bucket *hash;
653 struct fib_nh_exception *fnhe;
654 struct rtable *rt;
655 unsigned int i;
656 int depth;
657 u32 hval = fnhe_hashfun(daddr);
658
659 spin_lock_bh(&fnhe_lock);
660
661 hash = rcu_dereference(nh->nh_exceptions);
662 if (!hash) {
663 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
664 if (!hash)
665 goto out_unlock;
666 rcu_assign_pointer(nh->nh_exceptions, hash);
667 }
668
669 hash += hval;
670
671 depth = 0;
672 for (fnhe = rcu_dereference(hash->chain); fnhe;
673 fnhe = rcu_dereference(fnhe->fnhe_next)) {
674 if (fnhe->fnhe_daddr == daddr)
675 break;
676 depth++;
677 }
678
679 if (fnhe) {
680 if (gw)
681 fnhe->fnhe_gw = gw;
682 if (pmtu) {
683 fnhe->fnhe_pmtu = pmtu;
684 fnhe->fnhe_expires = max(1UL, expires);
685 }
686 /* Update all cached dsts too */
687 rt = rcu_dereference(fnhe->fnhe_rth_input);
688 if (rt)
689 fill_route_from_fnhe(rt, fnhe);
690 rt = rcu_dereference(fnhe->fnhe_rth_output);
691 if (rt)
692 fill_route_from_fnhe(rt, fnhe);
693 } else {
694 if (depth > FNHE_RECLAIM_DEPTH)
695 fnhe = fnhe_oldest(hash);
696 else {
697 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
698 if (!fnhe)
699 goto out_unlock;
700
701 fnhe->fnhe_next = hash->chain;
702 rcu_assign_pointer(hash->chain, fnhe);
703 }
704 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
705 fnhe->fnhe_daddr = daddr;
706 fnhe->fnhe_gw = gw;
707 fnhe->fnhe_pmtu = pmtu;
708 fnhe->fnhe_expires = expires;
709
710 /* Exception created; mark the cached routes for the nexthop
711 * stale, so anyone caching it rechecks if this exception
712 * applies to them.
713 */
714 rt = rcu_dereference(nh->nh_rth_input);
715 if (rt)
716 rt->dst.obsolete = DST_OBSOLETE_KILL;
717
718 for_each_possible_cpu(i) {
719 struct rtable __rcu **prt;
720 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
721 rt = rcu_dereference(*prt);
722 if (rt)
723 rt->dst.obsolete = DST_OBSOLETE_KILL;
724 }
725 }
726
727 fnhe->fnhe_stamp = jiffies;
728
729 out_unlock:
730 spin_unlock_bh(&fnhe_lock);
731 }
732
733 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
734 bool kill_route)
735 {
736 __be32 new_gw = icmp_hdr(skb)->un.gateway;
737 __be32 old_gw = ip_hdr(skb)->saddr;
738 struct net_device *dev = skb->dev;
739 struct in_device *in_dev;
740 struct fib_result res;
741 struct neighbour *n;
742 struct net *net;
743
744 switch (icmp_hdr(skb)->code & 7) {
745 case ICMP_REDIR_NET:
746 case ICMP_REDIR_NETTOS:
747 case ICMP_REDIR_HOST:
748 case ICMP_REDIR_HOSTTOS:
749 break;
750
751 default:
752 return;
753 }
754
755 if (rt->rt_gateway != old_gw)
756 return;
757
758 in_dev = __in_dev_get_rcu(dev);
759 if (!in_dev)
760 return;
761
762 net = dev_net(dev);
763 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
764 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
765 ipv4_is_zeronet(new_gw))
766 goto reject_redirect;
767
768 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
769 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
770 goto reject_redirect;
771 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
772 goto reject_redirect;
773 } else {
774 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
775 goto reject_redirect;
776 }
777
778 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
779 if (!n)
780 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
781 if (!IS_ERR(n)) {
782 if (!(n->nud_state & NUD_VALID)) {
783 neigh_event_send(n, NULL);
784 } else {
785 if (fib_lookup(net, fl4, &res, 0) == 0) {
786 struct fib_nh *nh = &FIB_RES_NH(res);
787
788 update_or_create_fnhe(nh, fl4->daddr, new_gw,
789 0, jiffies + ip_rt_gc_timeout);
790 }
791 if (kill_route)
792 rt->dst.obsolete = DST_OBSOLETE_KILL;
793 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
794 }
795 neigh_release(n);
796 }
797 return;
798
799 reject_redirect:
800 #ifdef CONFIG_IP_ROUTE_VERBOSE
801 if (IN_DEV_LOG_MARTIANS(in_dev)) {
802 const struct iphdr *iph = (const struct iphdr *) skb->data;
803 __be32 daddr = iph->daddr;
804 __be32 saddr = iph->saddr;
805
806 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
807 " Advised path = %pI4 -> %pI4\n",
808 &old_gw, dev->name, &new_gw,
809 &saddr, &daddr);
810 }
811 #endif
812 ;
813 }
814
815 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
816 {
817 struct rtable *rt;
818 struct flowi4 fl4;
819 const struct iphdr *iph = (const struct iphdr *) skb->data;
820 struct net *net = dev_net(skb->dev);
821 int oif = skb->dev->ifindex;
822 u8 tos = RT_TOS(iph->tos);
823 u8 prot = iph->protocol;
824 u32 mark = skb->mark;
825
826 rt = (struct rtable *) dst;
827
828 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
829 __ip_do_redirect(rt, skb, &fl4, true);
830 }
831
832 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
833 {
834 struct rtable *rt = (struct rtable *)dst;
835 struct dst_entry *ret = dst;
836
837 if (rt) {
838 if (dst->obsolete > 0) {
839 ip_rt_put(rt);
840 ret = NULL;
841 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
842 rt->dst.expires) {
843 ip_rt_put(rt);
844 ret = NULL;
845 }
846 }
847 return ret;
848 }
849
850 /*
851 * Algorithm:
852 * 1. The first ip_rt_redirect_number redirects are sent
853 * with exponential backoff, then we stop sending them at all,
854 * assuming that the host ignores our redirects.
855 * 2. If we did not see packets requiring redirects
856 * during ip_rt_redirect_silence, we assume that the host
857 * forgot redirected route and start to send redirects again.
858 *
859 * This algorithm is much cheaper and more intelligent than dumb load limiting
860 * in icmp.c.
861 *
862 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
863 * and "frag. need" (breaks PMTU discovery) in icmp.c.
864 */
865
866 void ip_rt_send_redirect(struct sk_buff *skb)
867 {
868 struct rtable *rt = skb_rtable(skb);
869 struct in_device *in_dev;
870 struct inet_peer *peer;
871 struct net *net;
872 int log_martians;
873 int vif;
874
875 rcu_read_lock();
876 in_dev = __in_dev_get_rcu(rt->dst.dev);
877 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
878 rcu_read_unlock();
879 return;
880 }
881 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
882 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
883 rcu_read_unlock();
884
885 net = dev_net(rt->dst.dev);
886 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
887 if (!peer) {
888 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
889 rt_nexthop(rt, ip_hdr(skb)->daddr));
890 return;
891 }
892
893 /* No redirected packets during ip_rt_redirect_silence;
894 * reset the algorithm.
895 */
896 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
897 peer->rate_tokens = 0;
898
899 /* Too many ignored redirects; do not send anything
900 * set dst.rate_last to the last seen redirected packet.
901 */
902 if (peer->rate_tokens >= ip_rt_redirect_number) {
903 peer->rate_last = jiffies;
904 goto out_put_peer;
905 }
906
907 /* Check for load limit; set rate_last to the latest sent
908 * redirect.
909 */
910 if (peer->rate_tokens == 0 ||
911 time_after(jiffies,
912 (peer->rate_last +
913 (ip_rt_redirect_load << peer->rate_tokens)))) {
914 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
915
916 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
917 peer->rate_last = jiffies;
918 ++peer->rate_tokens;
919 #ifdef CONFIG_IP_ROUTE_VERBOSE
920 if (log_martians &&
921 peer->rate_tokens == ip_rt_redirect_number)
922 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
923 &ip_hdr(skb)->saddr, inet_iif(skb),
924 &ip_hdr(skb)->daddr, &gw);
925 #endif
926 }
927 out_put_peer:
928 inet_putpeer(peer);
929 }
930
931 static int ip_error(struct sk_buff *skb)
932 {
933 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
934 struct rtable *rt = skb_rtable(skb);
935 struct inet_peer *peer;
936 unsigned long now;
937 struct net *net;
938 bool send;
939 int code;
940
941 /* IP on this device is disabled. */
942 if (!in_dev)
943 goto out;
944
945 net = dev_net(rt->dst.dev);
946 if (!IN_DEV_FORWARD(in_dev)) {
947 switch (rt->dst.error) {
948 case EHOSTUNREACH:
949 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
950 break;
951
952 case ENETUNREACH:
953 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
954 break;
955 }
956 goto out;
957 }
958
959 switch (rt->dst.error) {
960 case EINVAL:
961 default:
962 goto out;
963 case EHOSTUNREACH:
964 code = ICMP_HOST_UNREACH;
965 break;
966 case ENETUNREACH:
967 code = ICMP_NET_UNREACH;
968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
969 break;
970 case EACCES:
971 code = ICMP_PKT_FILTERED;
972 break;
973 }
974
975 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
976 l3mdev_master_ifindex(skb->dev), 1);
977
978 send = true;
979 if (peer) {
980 now = jiffies;
981 peer->rate_tokens += now - peer->rate_last;
982 if (peer->rate_tokens > ip_rt_error_burst)
983 peer->rate_tokens = ip_rt_error_burst;
984 peer->rate_last = now;
985 if (peer->rate_tokens >= ip_rt_error_cost)
986 peer->rate_tokens -= ip_rt_error_cost;
987 else
988 send = false;
989 inet_putpeer(peer);
990 }
991 if (send)
992 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
993
994 out: kfree_skb(skb);
995 return 0;
996 }
997
998 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
999 {
1000 struct dst_entry *dst = &rt->dst;
1001 struct fib_result res;
1002
1003 if (dst_metric_locked(dst, RTAX_MTU))
1004 return;
1005
1006 if (ipv4_mtu(dst) < mtu)
1007 return;
1008
1009 if (mtu < ip_rt_min_pmtu)
1010 mtu = ip_rt_min_pmtu;
1011
1012 if (rt->rt_pmtu == mtu &&
1013 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1014 return;
1015
1016 rcu_read_lock();
1017 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1018 struct fib_nh *nh = &FIB_RES_NH(res);
1019
1020 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
1021 jiffies + ip_rt_mtu_expires);
1022 }
1023 rcu_read_unlock();
1024 }
1025
1026 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1027 struct sk_buff *skb, u32 mtu)
1028 {
1029 struct rtable *rt = (struct rtable *) dst;
1030 struct flowi4 fl4;
1031
1032 ip_rt_build_flow_key(&fl4, sk, skb);
1033 __ip_rt_update_pmtu(rt, &fl4, mtu);
1034 }
1035
1036 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1037 int oif, u32 mark, u8 protocol, int flow_flags)
1038 {
1039 const struct iphdr *iph = (const struct iphdr *) skb->data;
1040 struct flowi4 fl4;
1041 struct rtable *rt;
1042
1043 if (!mark)
1044 mark = IP4_REPLY_MARK(net, skb->mark);
1045
1046 __build_flow_key(net, &fl4, NULL, iph, oif,
1047 RT_TOS(iph->tos), protocol, mark, flow_flags);
1048 rt = __ip_route_output_key(net, &fl4);
1049 if (!IS_ERR(rt)) {
1050 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 ip_rt_put(rt);
1052 }
1053 }
1054 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1055
1056 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1057 {
1058 const struct iphdr *iph = (const struct iphdr *) skb->data;
1059 struct flowi4 fl4;
1060 struct rtable *rt;
1061
1062 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1063
1064 if (!fl4.flowi4_mark)
1065 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1066
1067 rt = __ip_route_output_key(sock_net(sk), &fl4);
1068 if (!IS_ERR(rt)) {
1069 __ip_rt_update_pmtu(rt, &fl4, mtu);
1070 ip_rt_put(rt);
1071 }
1072 }
1073
1074 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1075 {
1076 const struct iphdr *iph = (const struct iphdr *) skb->data;
1077 struct flowi4 fl4;
1078 struct rtable *rt;
1079 struct dst_entry *odst = NULL;
1080 bool new = false;
1081 struct net *net = sock_net(sk);
1082
1083 bh_lock_sock(sk);
1084
1085 if (!ip_sk_accept_pmtu(sk))
1086 goto out;
1087
1088 odst = sk_dst_get(sk);
1089
1090 if (sock_owned_by_user(sk) || !odst) {
1091 __ipv4_sk_update_pmtu(skb, sk, mtu);
1092 goto out;
1093 }
1094
1095 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1096
1097 rt = (struct rtable *)odst;
1098 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1099 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1100 if (IS_ERR(rt))
1101 goto out;
1102
1103 new = true;
1104 }
1105
1106 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1107
1108 if (!dst_check(&rt->dst, 0)) {
1109 if (new)
1110 dst_release(&rt->dst);
1111
1112 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1113 if (IS_ERR(rt))
1114 goto out;
1115
1116 new = true;
1117 }
1118
1119 if (new)
1120 sk_dst_set(sk, &rt->dst);
1121
1122 out:
1123 bh_unlock_sock(sk);
1124 dst_release(odst);
1125 }
1126 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1127
1128 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1129 int oif, u32 mark, u8 protocol, int flow_flags)
1130 {
1131 const struct iphdr *iph = (const struct iphdr *) skb->data;
1132 struct flowi4 fl4;
1133 struct rtable *rt;
1134
1135 __build_flow_key(net, &fl4, NULL, iph, oif,
1136 RT_TOS(iph->tos), protocol, mark, flow_flags);
1137 rt = __ip_route_output_key(net, &fl4);
1138 if (!IS_ERR(rt)) {
1139 __ip_do_redirect(rt, skb, &fl4, false);
1140 ip_rt_put(rt);
1141 }
1142 }
1143 EXPORT_SYMBOL_GPL(ipv4_redirect);
1144
1145 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1146 {
1147 const struct iphdr *iph = (const struct iphdr *) skb->data;
1148 struct flowi4 fl4;
1149 struct rtable *rt;
1150 struct net *net = sock_net(sk);
1151
1152 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1153 rt = __ip_route_output_key(net, &fl4);
1154 if (!IS_ERR(rt)) {
1155 __ip_do_redirect(rt, skb, &fl4, false);
1156 ip_rt_put(rt);
1157 }
1158 }
1159 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1160
1161 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1162 {
1163 struct rtable *rt = (struct rtable *) dst;
1164
1165 /* All IPV4 dsts are created with ->obsolete set to the value
1166 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1167 * into this function always.
1168 *
1169 * When a PMTU/redirect information update invalidates a route,
1170 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1171 * DST_OBSOLETE_DEAD by dst_free().
1172 */
1173 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1174 return NULL;
1175 return dst;
1176 }
1177
1178 static void ipv4_link_failure(struct sk_buff *skb)
1179 {
1180 struct rtable *rt;
1181
1182 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1183
1184 rt = skb_rtable(skb);
1185 if (rt)
1186 dst_set_expires(&rt->dst, 0);
1187 }
1188
1189 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1190 {
1191 pr_debug("%s: %pI4 -> %pI4, %s\n",
1192 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1193 skb->dev ? skb->dev->name : "?");
1194 kfree_skb(skb);
1195 WARN_ON(1);
1196 return 0;
1197 }
1198
1199 /*
1200 We do not cache source address of outgoing interface,
1201 because it is used only by IP RR, TS and SRR options,
1202 so that it out of fast path.
1203
1204 BTW remember: "addr" is allowed to be not aligned
1205 in IP options!
1206 */
1207
1208 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1209 {
1210 __be32 src;
1211
1212 if (rt_is_output_route(rt))
1213 src = ip_hdr(skb)->saddr;
1214 else {
1215 struct fib_result res;
1216 struct flowi4 fl4;
1217 struct iphdr *iph;
1218
1219 iph = ip_hdr(skb);
1220
1221 memset(&fl4, 0, sizeof(fl4));
1222 fl4.daddr = iph->daddr;
1223 fl4.saddr = iph->saddr;
1224 fl4.flowi4_tos = RT_TOS(iph->tos);
1225 fl4.flowi4_oif = rt->dst.dev->ifindex;
1226 fl4.flowi4_iif = skb->dev->ifindex;
1227 fl4.flowi4_mark = skb->mark;
1228
1229 rcu_read_lock();
1230 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1231 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1232 else
1233 src = inet_select_addr(rt->dst.dev,
1234 rt_nexthop(rt, iph->daddr),
1235 RT_SCOPE_UNIVERSE);
1236 rcu_read_unlock();
1237 }
1238 memcpy(addr, &src, 4);
1239 }
1240
1241 #ifdef CONFIG_IP_ROUTE_CLASSID
1242 static void set_class_tag(struct rtable *rt, u32 tag)
1243 {
1244 if (!(rt->dst.tclassid & 0xFFFF))
1245 rt->dst.tclassid |= tag & 0xFFFF;
1246 if (!(rt->dst.tclassid & 0xFFFF0000))
1247 rt->dst.tclassid |= tag & 0xFFFF0000;
1248 }
1249 #endif
1250
1251 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1252 {
1253 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1254
1255 if (advmss == 0) {
1256 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1257 ip_rt_min_advmss);
1258 if (advmss > 65535 - 40)
1259 advmss = 65535 - 40;
1260 }
1261 return advmss;
1262 }
1263
1264 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1265 {
1266 const struct rtable *rt = (const struct rtable *) dst;
1267 unsigned int mtu = rt->rt_pmtu;
1268
1269 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1270 mtu = dst_metric_raw(dst, RTAX_MTU);
1271
1272 if (mtu)
1273 return mtu;
1274
1275 mtu = dst->dev->mtu;
1276
1277 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1278 if (rt->rt_uses_gateway && mtu > 576)
1279 mtu = 576;
1280 }
1281
1282 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1283
1284 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1285 }
1286
1287 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1288 {
1289 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1290 struct fib_nh_exception *fnhe;
1291 u32 hval;
1292
1293 if (!hash)
1294 return NULL;
1295
1296 hval = fnhe_hashfun(daddr);
1297
1298 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1299 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1300 if (fnhe->fnhe_daddr == daddr)
1301 return fnhe;
1302 }
1303 return NULL;
1304 }
1305
1306 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1307 __be32 daddr)
1308 {
1309 bool ret = false;
1310
1311 spin_lock_bh(&fnhe_lock);
1312
1313 if (daddr == fnhe->fnhe_daddr) {
1314 struct rtable __rcu **porig;
1315 struct rtable *orig;
1316 int genid = fnhe_genid(dev_net(rt->dst.dev));
1317
1318 if (rt_is_input_route(rt))
1319 porig = &fnhe->fnhe_rth_input;
1320 else
1321 porig = &fnhe->fnhe_rth_output;
1322 orig = rcu_dereference(*porig);
1323
1324 if (fnhe->fnhe_genid != genid) {
1325 fnhe->fnhe_genid = genid;
1326 fnhe->fnhe_gw = 0;
1327 fnhe->fnhe_pmtu = 0;
1328 fnhe->fnhe_expires = 0;
1329 fnhe_flush_routes(fnhe);
1330 orig = NULL;
1331 }
1332 fill_route_from_fnhe(rt, fnhe);
1333 if (!rt->rt_gateway)
1334 rt->rt_gateway = daddr;
1335
1336 if (!(rt->dst.flags & DST_NOCACHE)) {
1337 rcu_assign_pointer(*porig, rt);
1338 if (orig)
1339 rt_free(orig);
1340 ret = true;
1341 }
1342
1343 fnhe->fnhe_stamp = jiffies;
1344 }
1345 spin_unlock_bh(&fnhe_lock);
1346
1347 return ret;
1348 }
1349
1350 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1351 {
1352 struct rtable *orig, *prev, **p;
1353 bool ret = true;
1354
1355 if (rt_is_input_route(rt)) {
1356 p = (struct rtable **)&nh->nh_rth_input;
1357 } else {
1358 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1359 }
1360 orig = *p;
1361
1362 prev = cmpxchg(p, orig, rt);
1363 if (prev == orig) {
1364 if (orig)
1365 rt_free(orig);
1366 } else
1367 ret = false;
1368
1369 return ret;
1370 }
1371
1372 struct uncached_list {
1373 spinlock_t lock;
1374 struct list_head head;
1375 };
1376
1377 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1378
1379 static void rt_add_uncached_list(struct rtable *rt)
1380 {
1381 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1382
1383 rt->rt_uncached_list = ul;
1384
1385 spin_lock_bh(&ul->lock);
1386 list_add_tail(&rt->rt_uncached, &ul->head);
1387 spin_unlock_bh(&ul->lock);
1388 }
1389
1390 static void ipv4_dst_destroy(struct dst_entry *dst)
1391 {
1392 struct rtable *rt = (struct rtable *) dst;
1393
1394 if (!list_empty(&rt->rt_uncached)) {
1395 struct uncached_list *ul = rt->rt_uncached_list;
1396
1397 spin_lock_bh(&ul->lock);
1398 list_del(&rt->rt_uncached);
1399 spin_unlock_bh(&ul->lock);
1400 }
1401 }
1402
1403 void rt_flush_dev(struct net_device *dev)
1404 {
1405 struct net *net = dev_net(dev);
1406 struct rtable *rt;
1407 int cpu;
1408
1409 for_each_possible_cpu(cpu) {
1410 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1411
1412 spin_lock_bh(&ul->lock);
1413 list_for_each_entry(rt, &ul->head, rt_uncached) {
1414 if (rt->dst.dev != dev)
1415 continue;
1416 rt->dst.dev = net->loopback_dev;
1417 dev_hold(rt->dst.dev);
1418 dev_put(dev);
1419 }
1420 spin_unlock_bh(&ul->lock);
1421 }
1422 }
1423
1424 static bool rt_cache_valid(const struct rtable *rt)
1425 {
1426 return rt &&
1427 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1428 !rt_is_expired(rt);
1429 }
1430
1431 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1432 const struct fib_result *res,
1433 struct fib_nh_exception *fnhe,
1434 struct fib_info *fi, u16 type, u32 itag)
1435 {
1436 bool cached = false;
1437
1438 if (fi) {
1439 struct fib_nh *nh = &FIB_RES_NH(*res);
1440
1441 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1442 rt->rt_gateway = nh->nh_gw;
1443 rt->rt_uses_gateway = 1;
1444 }
1445 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1446 #ifdef CONFIG_IP_ROUTE_CLASSID
1447 rt->dst.tclassid = nh->nh_tclassid;
1448 #endif
1449 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1450 if (unlikely(fnhe))
1451 cached = rt_bind_exception(rt, fnhe, daddr);
1452 else if (!(rt->dst.flags & DST_NOCACHE))
1453 cached = rt_cache_route(nh, rt);
1454 if (unlikely(!cached)) {
1455 /* Routes we intend to cache in nexthop exception or
1456 * FIB nexthop have the DST_NOCACHE bit clear.
1457 * However, if we are unsuccessful at storing this
1458 * route into the cache we really need to set it.
1459 */
1460 rt->dst.flags |= DST_NOCACHE;
1461 if (!rt->rt_gateway)
1462 rt->rt_gateway = daddr;
1463 rt_add_uncached_list(rt);
1464 }
1465 } else
1466 rt_add_uncached_list(rt);
1467
1468 #ifdef CONFIG_IP_ROUTE_CLASSID
1469 #ifdef CONFIG_IP_MULTIPLE_TABLES
1470 set_class_tag(rt, res->tclassid);
1471 #endif
1472 set_class_tag(rt, itag);
1473 #endif
1474 }
1475
1476 struct rtable *rt_dst_alloc(struct net_device *dev,
1477 unsigned int flags, u16 type,
1478 bool nopolicy, bool noxfrm, bool will_cache)
1479 {
1480 struct rtable *rt;
1481
1482 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1483 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1484 (nopolicy ? DST_NOPOLICY : 0) |
1485 (noxfrm ? DST_NOXFRM : 0));
1486
1487 if (rt) {
1488 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1489 rt->rt_flags = flags;
1490 rt->rt_type = type;
1491 rt->rt_is_input = 0;
1492 rt->rt_iif = 0;
1493 rt->rt_pmtu = 0;
1494 rt->rt_gateway = 0;
1495 rt->rt_uses_gateway = 0;
1496 rt->rt_table_id = 0;
1497 INIT_LIST_HEAD(&rt->rt_uncached);
1498
1499 rt->dst.output = ip_output;
1500 if (flags & RTCF_LOCAL)
1501 rt->dst.input = ip_local_deliver;
1502 }
1503
1504 return rt;
1505 }
1506 EXPORT_SYMBOL(rt_dst_alloc);
1507
1508 /* called in rcu_read_lock() section */
1509 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1510 u8 tos, struct net_device *dev, int our)
1511 {
1512 struct rtable *rth;
1513 struct in_device *in_dev = __in_dev_get_rcu(dev);
1514 unsigned int flags = RTCF_MULTICAST;
1515 u32 itag = 0;
1516 int err;
1517
1518 /* Primary sanity checks. */
1519
1520 if (!in_dev)
1521 return -EINVAL;
1522
1523 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1524 skb->protocol != htons(ETH_P_IP))
1525 goto e_inval;
1526
1527 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1528 goto e_inval;
1529
1530 if (ipv4_is_zeronet(saddr)) {
1531 if (!ipv4_is_local_multicast(daddr))
1532 goto e_inval;
1533 } else {
1534 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1535 in_dev, &itag);
1536 if (err < 0)
1537 goto e_err;
1538 }
1539 if (our)
1540 flags |= RTCF_LOCAL;
1541
1542 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1543 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1544 if (!rth)
1545 goto e_nobufs;
1546
1547 #ifdef CONFIG_IP_ROUTE_CLASSID
1548 rth->dst.tclassid = itag;
1549 #endif
1550 rth->dst.output = ip_rt_bug;
1551 rth->rt_is_input= 1;
1552
1553 #ifdef CONFIG_IP_MROUTE
1554 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1555 rth->dst.input = ip_mr_input;
1556 #endif
1557 RT_CACHE_STAT_INC(in_slow_mc);
1558
1559 skb_dst_set(skb, &rth->dst);
1560 return 0;
1561
1562 e_nobufs:
1563 return -ENOBUFS;
1564 e_inval:
1565 return -EINVAL;
1566 e_err:
1567 return err;
1568 }
1569
1570
1571 static void ip_handle_martian_source(struct net_device *dev,
1572 struct in_device *in_dev,
1573 struct sk_buff *skb,
1574 __be32 daddr,
1575 __be32 saddr)
1576 {
1577 RT_CACHE_STAT_INC(in_martian_src);
1578 #ifdef CONFIG_IP_ROUTE_VERBOSE
1579 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1580 /*
1581 * RFC1812 recommendation, if source is martian,
1582 * the only hint is MAC header.
1583 */
1584 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1585 &daddr, &saddr, dev->name);
1586 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1587 print_hex_dump(KERN_WARNING, "ll header: ",
1588 DUMP_PREFIX_OFFSET, 16, 1,
1589 skb_mac_header(skb),
1590 dev->hard_header_len, true);
1591 }
1592 }
1593 #endif
1594 }
1595
1596 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1597 {
1598 struct fnhe_hash_bucket *hash;
1599 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1600 u32 hval = fnhe_hashfun(daddr);
1601
1602 spin_lock_bh(&fnhe_lock);
1603
1604 hash = rcu_dereference_protected(nh->nh_exceptions,
1605 lockdep_is_held(&fnhe_lock));
1606 hash += hval;
1607
1608 fnhe_p = &hash->chain;
1609 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1610 while (fnhe) {
1611 if (fnhe->fnhe_daddr == daddr) {
1612 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1613 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1614 fnhe_flush_routes(fnhe);
1615 kfree_rcu(fnhe, rcu);
1616 break;
1617 }
1618 fnhe_p = &fnhe->fnhe_next;
1619 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1620 lockdep_is_held(&fnhe_lock));
1621 }
1622
1623 spin_unlock_bh(&fnhe_lock);
1624 }
1625
1626 static void set_lwt_redirect(struct rtable *rth)
1627 {
1628 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1629 rth->dst.lwtstate->orig_output = rth->dst.output;
1630 rth->dst.output = lwtunnel_output;
1631 }
1632
1633 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1634 rth->dst.lwtstate->orig_input = rth->dst.input;
1635 rth->dst.input = lwtunnel_input;
1636 }
1637 }
1638
1639 /* called in rcu_read_lock() section */
1640 static int __mkroute_input(struct sk_buff *skb,
1641 const struct fib_result *res,
1642 struct in_device *in_dev,
1643 __be32 daddr, __be32 saddr, u32 tos)
1644 {
1645 struct fib_nh_exception *fnhe;
1646 struct rtable *rth;
1647 int err;
1648 struct in_device *out_dev;
1649 bool do_cache;
1650 u32 itag = 0;
1651
1652 /* get a working reference to the output device */
1653 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1654 if (!out_dev) {
1655 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1656 return -EINVAL;
1657 }
1658
1659 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1660 in_dev->dev, in_dev, &itag);
1661 if (err < 0) {
1662 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1663 saddr);
1664
1665 goto cleanup;
1666 }
1667
1668 do_cache = res->fi && !itag;
1669 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1670 skb->protocol == htons(ETH_P_IP) &&
1671 (IN_DEV_SHARED_MEDIA(out_dev) ||
1672 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1673 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1674
1675 if (skb->protocol != htons(ETH_P_IP)) {
1676 /* Not IP (i.e. ARP). Do not create route, if it is
1677 * invalid for proxy arp. DNAT routes are always valid.
1678 *
1679 * Proxy arp feature have been extended to allow, ARP
1680 * replies back to the same interface, to support
1681 * Private VLAN switch technologies. See arp.c.
1682 */
1683 if (out_dev == in_dev &&
1684 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1685 err = -EINVAL;
1686 goto cleanup;
1687 }
1688 }
1689
1690 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1691 if (do_cache) {
1692 if (fnhe) {
1693 rth = rcu_dereference(fnhe->fnhe_rth_input);
1694 if (rth && rth->dst.expires &&
1695 time_after(jiffies, rth->dst.expires)) {
1696 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1697 fnhe = NULL;
1698 } else {
1699 goto rt_cache;
1700 }
1701 }
1702
1703 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1704
1705 rt_cache:
1706 if (rt_cache_valid(rth)) {
1707 skb_dst_set_noref(skb, &rth->dst);
1708 goto out;
1709 }
1710 }
1711
1712 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1713 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1714 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1715 if (!rth) {
1716 err = -ENOBUFS;
1717 goto cleanup;
1718 }
1719
1720 rth->rt_is_input = 1;
1721 if (res->table)
1722 rth->rt_table_id = res->table->tb_id;
1723 RT_CACHE_STAT_INC(in_slow_tot);
1724
1725 rth->dst.input = ip_forward;
1726
1727 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1728 set_lwt_redirect(rth);
1729 skb_dst_set(skb, &rth->dst);
1730 out:
1731 err = 0;
1732 cleanup:
1733 return err;
1734 }
1735
1736 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1737
1738 /* To make ICMP packets follow the right flow, the multipath hash is
1739 * calculated from the inner IP addresses in reverse order.
1740 */
1741 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1742 {
1743 const struct iphdr *outer_iph = ip_hdr(skb);
1744 struct icmphdr _icmph;
1745 const struct icmphdr *icmph;
1746 struct iphdr _inner_iph;
1747 const struct iphdr *inner_iph;
1748
1749 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1750 goto standard_hash;
1751
1752 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1753 &_icmph);
1754 if (!icmph)
1755 goto standard_hash;
1756
1757 if (icmph->type != ICMP_DEST_UNREACH &&
1758 icmph->type != ICMP_REDIRECT &&
1759 icmph->type != ICMP_TIME_EXCEEDED &&
1760 icmph->type != ICMP_PARAMETERPROB) {
1761 goto standard_hash;
1762 }
1763
1764 inner_iph = skb_header_pointer(skb,
1765 outer_iph->ihl * 4 + sizeof(_icmph),
1766 sizeof(_inner_iph), &_inner_iph);
1767 if (!inner_iph)
1768 goto standard_hash;
1769
1770 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1771
1772 standard_hash:
1773 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1774 }
1775
1776 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1777
1778 static int ip_mkroute_input(struct sk_buff *skb,
1779 struct fib_result *res,
1780 struct in_device *in_dev,
1781 __be32 daddr, __be32 saddr, u32 tos)
1782 {
1783 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1784 if (res->fi && res->fi->fib_nhs > 1) {
1785 int h;
1786
1787 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1788 h = ip_multipath_icmp_hash(skb);
1789 else
1790 h = fib_multipath_hash(saddr, daddr);
1791 fib_select_multipath(res, h);
1792 }
1793 #endif
1794
1795 /* create a routing cache entry */
1796 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1797 }
1798
1799 /*
1800 * NOTE. We drop all the packets that has local source
1801 * addresses, because every properly looped back packet
1802 * must have correct destination already attached by output routine.
1803 *
1804 * Such approach solves two big problems:
1805 * 1. Not simplex devices are handled properly.
1806 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1807 * called with rcu_read_lock()
1808 */
1809
1810 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1811 u8 tos, struct net_device *dev)
1812 {
1813 struct fib_result res;
1814 struct in_device *in_dev = __in_dev_get_rcu(dev);
1815 struct ip_tunnel_info *tun_info;
1816 struct flowi4 fl4;
1817 unsigned int flags = 0;
1818 u32 itag = 0;
1819 struct rtable *rth;
1820 int err = -EINVAL;
1821 struct net *net = dev_net(dev);
1822 bool do_cache;
1823
1824 /* IP on this device is disabled. */
1825
1826 if (!in_dev)
1827 goto out;
1828
1829 /* Check for the most weird martians, which can be not detected
1830 by fib_lookup.
1831 */
1832
1833 tun_info = skb_tunnel_info(skb);
1834 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1835 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1836 else
1837 fl4.flowi4_tun_key.tun_id = 0;
1838 skb_dst_drop(skb);
1839
1840 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1841 goto martian_source;
1842
1843 res.fi = NULL;
1844 res.table = NULL;
1845 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1846 goto brd_input;
1847
1848 /* Accept zero addresses only to limited broadcast;
1849 * I even do not know to fix it or not. Waiting for complains :-)
1850 */
1851 if (ipv4_is_zeronet(saddr))
1852 goto martian_source;
1853
1854 if (ipv4_is_zeronet(daddr))
1855 goto martian_destination;
1856
1857 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1858 * and call it once if daddr or/and saddr are loopback addresses
1859 */
1860 if (ipv4_is_loopback(daddr)) {
1861 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1862 goto martian_destination;
1863 } else if (ipv4_is_loopback(saddr)) {
1864 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1865 goto martian_source;
1866 }
1867
1868 /*
1869 * Now we are ready to route packet.
1870 */
1871 fl4.flowi4_oif = 0;
1872 fl4.flowi4_iif = dev->ifindex;
1873 fl4.flowi4_mark = skb->mark;
1874 fl4.flowi4_tos = tos;
1875 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1876 fl4.flowi4_flags = 0;
1877 fl4.daddr = daddr;
1878 fl4.saddr = saddr;
1879 fl4.flowi4_uid = sock_net_uid(net, NULL);
1880 err = fib_lookup(net, &fl4, &res, 0);
1881 if (err != 0) {
1882 if (!IN_DEV_FORWARD(in_dev))
1883 err = -EHOSTUNREACH;
1884 goto no_route;
1885 }
1886
1887 if (res.type == RTN_BROADCAST)
1888 goto brd_input;
1889
1890 if (res.type == RTN_LOCAL) {
1891 err = fib_validate_source(skb, saddr, daddr, tos,
1892 0, dev, in_dev, &itag);
1893 if (err < 0)
1894 goto martian_source;
1895 goto local_input;
1896 }
1897
1898 if (!IN_DEV_FORWARD(in_dev)) {
1899 err = -EHOSTUNREACH;
1900 goto no_route;
1901 }
1902 if (res.type != RTN_UNICAST)
1903 goto martian_destination;
1904
1905 err = ip_mkroute_input(skb, &res, in_dev, daddr, saddr, tos);
1906 out: return err;
1907
1908 brd_input:
1909 if (skb->protocol != htons(ETH_P_IP))
1910 goto e_inval;
1911
1912 if (!ipv4_is_zeronet(saddr)) {
1913 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1914 in_dev, &itag);
1915 if (err < 0)
1916 goto martian_source;
1917 }
1918 flags |= RTCF_BROADCAST;
1919 res.type = RTN_BROADCAST;
1920 RT_CACHE_STAT_INC(in_brd);
1921
1922 local_input:
1923 do_cache = false;
1924 if (res.fi) {
1925 if (!itag) {
1926 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1927 if (rt_cache_valid(rth)) {
1928 skb_dst_set_noref(skb, &rth->dst);
1929 err = 0;
1930 goto out;
1931 }
1932 do_cache = true;
1933 }
1934 }
1935
1936 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
1937 flags | RTCF_LOCAL, res.type,
1938 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1939 if (!rth)
1940 goto e_nobufs;
1941
1942 rth->dst.output= ip_rt_bug;
1943 #ifdef CONFIG_IP_ROUTE_CLASSID
1944 rth->dst.tclassid = itag;
1945 #endif
1946 rth->rt_is_input = 1;
1947 if (res.table)
1948 rth->rt_table_id = res.table->tb_id;
1949
1950 RT_CACHE_STAT_INC(in_slow_tot);
1951 if (res.type == RTN_UNREACHABLE) {
1952 rth->dst.input= ip_error;
1953 rth->dst.error= -err;
1954 rth->rt_flags &= ~RTCF_LOCAL;
1955 }
1956
1957 if (do_cache) {
1958 struct fib_nh *nh = &FIB_RES_NH(res);
1959
1960 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1961 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1962 WARN_ON(rth->dst.input == lwtunnel_input);
1963 rth->dst.lwtstate->orig_input = rth->dst.input;
1964 rth->dst.input = lwtunnel_input;
1965 }
1966
1967 if (unlikely(!rt_cache_route(nh, rth))) {
1968 rth->dst.flags |= DST_NOCACHE;
1969 rt_add_uncached_list(rth);
1970 }
1971 }
1972 skb_dst_set(skb, &rth->dst);
1973 err = 0;
1974 goto out;
1975
1976 no_route:
1977 RT_CACHE_STAT_INC(in_no_route);
1978 res.type = RTN_UNREACHABLE;
1979 res.fi = NULL;
1980 res.table = NULL;
1981 goto local_input;
1982
1983 /*
1984 * Do not cache martian addresses: they should be logged (RFC1812)
1985 */
1986 martian_destination:
1987 RT_CACHE_STAT_INC(in_martian_dst);
1988 #ifdef CONFIG_IP_ROUTE_VERBOSE
1989 if (IN_DEV_LOG_MARTIANS(in_dev))
1990 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1991 &daddr, &saddr, dev->name);
1992 #endif
1993
1994 e_inval:
1995 err = -EINVAL;
1996 goto out;
1997
1998 e_nobufs:
1999 err = -ENOBUFS;
2000 goto out;
2001
2002 martian_source:
2003 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2004 goto out;
2005 }
2006
2007 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2008 u8 tos, struct net_device *dev)
2009 {
2010 int res;
2011
2012 tos &= IPTOS_RT_MASK;
2013 rcu_read_lock();
2014
2015 /* Multicast recognition logic is moved from route cache to here.
2016 The problem was that too many Ethernet cards have broken/missing
2017 hardware multicast filters :-( As result the host on multicasting
2018 network acquires a lot of useless route cache entries, sort of
2019 SDR messages from all the world. Now we try to get rid of them.
2020 Really, provided software IP multicast filter is organized
2021 reasonably (at least, hashed), it does not result in a slowdown
2022 comparing with route cache reject entries.
2023 Note, that multicast routers are not affected, because
2024 route cache entry is created eventually.
2025 */
2026 if (ipv4_is_multicast(daddr)) {
2027 struct in_device *in_dev = __in_dev_get_rcu(dev);
2028 int our = 0;
2029
2030 if (in_dev)
2031 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2032 ip_hdr(skb)->protocol);
2033
2034 /* check l3 master if no match yet */
2035 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2036 struct in_device *l3_in_dev;
2037
2038 l3_in_dev = __in_dev_get_rcu(skb->dev);
2039 if (l3_in_dev)
2040 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2041 ip_hdr(skb)->protocol);
2042 }
2043
2044 res = -EINVAL;
2045 if (our
2046 #ifdef CONFIG_IP_MROUTE
2047 ||
2048 (!ipv4_is_local_multicast(daddr) &&
2049 IN_DEV_MFORWARD(in_dev))
2050 #endif
2051 ) {
2052 res = ip_route_input_mc(skb, daddr, saddr,
2053 tos, dev, our);
2054 }
2055 rcu_read_unlock();
2056 return res;
2057 }
2058 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2059 rcu_read_unlock();
2060 return res;
2061 }
2062 EXPORT_SYMBOL(ip_route_input_noref);
2063
2064 /* called with rcu_read_lock() */
2065 static struct rtable *__mkroute_output(const struct fib_result *res,
2066 const struct flowi4 *fl4, int orig_oif,
2067 struct net_device *dev_out,
2068 unsigned int flags)
2069 {
2070 struct fib_info *fi = res->fi;
2071 struct fib_nh_exception *fnhe;
2072 struct in_device *in_dev;
2073 u16 type = res->type;
2074 struct rtable *rth;
2075 bool do_cache;
2076
2077 in_dev = __in_dev_get_rcu(dev_out);
2078 if (!in_dev)
2079 return ERR_PTR(-EINVAL);
2080
2081 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2082 if (ipv4_is_loopback(fl4->saddr) &&
2083 !(dev_out->flags & IFF_LOOPBACK) &&
2084 !netif_is_l3_master(dev_out))
2085 return ERR_PTR(-EINVAL);
2086
2087 if (ipv4_is_lbcast(fl4->daddr))
2088 type = RTN_BROADCAST;
2089 else if (ipv4_is_multicast(fl4->daddr))
2090 type = RTN_MULTICAST;
2091 else if (ipv4_is_zeronet(fl4->daddr))
2092 return ERR_PTR(-EINVAL);
2093
2094 if (dev_out->flags & IFF_LOOPBACK)
2095 flags |= RTCF_LOCAL;
2096
2097 do_cache = true;
2098 if (type == RTN_BROADCAST) {
2099 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2100 fi = NULL;
2101 } else if (type == RTN_MULTICAST) {
2102 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2103 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2104 fl4->flowi4_proto))
2105 flags &= ~RTCF_LOCAL;
2106 else
2107 do_cache = false;
2108 /* If multicast route do not exist use
2109 * default one, but do not gateway in this case.
2110 * Yes, it is hack.
2111 */
2112 if (fi && res->prefixlen < 4)
2113 fi = NULL;
2114 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2115 (orig_oif != dev_out->ifindex)) {
2116 /* For local routes that require a particular output interface
2117 * we do not want to cache the result. Caching the result
2118 * causes incorrect behaviour when there are multiple source
2119 * addresses on the interface, the end result being that if the
2120 * intended recipient is waiting on that interface for the
2121 * packet he won't receive it because it will be delivered on
2122 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2123 * be set to the loopback interface as well.
2124 */
2125 fi = NULL;
2126 }
2127
2128 fnhe = NULL;
2129 do_cache &= fi != NULL;
2130 if (do_cache) {
2131 struct rtable __rcu **prth;
2132 struct fib_nh *nh = &FIB_RES_NH(*res);
2133
2134 fnhe = find_exception(nh, fl4->daddr);
2135 if (fnhe) {
2136 prth = &fnhe->fnhe_rth_output;
2137 rth = rcu_dereference(*prth);
2138 if (rth && rth->dst.expires &&
2139 time_after(jiffies, rth->dst.expires)) {
2140 ip_del_fnhe(nh, fl4->daddr);
2141 fnhe = NULL;
2142 } else {
2143 goto rt_cache;
2144 }
2145 }
2146
2147 if (unlikely(fl4->flowi4_flags &
2148 FLOWI_FLAG_KNOWN_NH &&
2149 !(nh->nh_gw &&
2150 nh->nh_scope == RT_SCOPE_LINK))) {
2151 do_cache = false;
2152 goto add;
2153 }
2154 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2155 rth = rcu_dereference(*prth);
2156
2157 rt_cache:
2158 if (rt_cache_valid(rth)) {
2159 dst_hold(&rth->dst);
2160 return rth;
2161 }
2162 }
2163
2164 add:
2165 rth = rt_dst_alloc(dev_out, flags, type,
2166 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2167 IN_DEV_CONF_GET(in_dev, NOXFRM),
2168 do_cache);
2169 if (!rth)
2170 return ERR_PTR(-ENOBUFS);
2171
2172 rth->rt_iif = orig_oif ? : 0;
2173 if (res->table)
2174 rth->rt_table_id = res->table->tb_id;
2175
2176 RT_CACHE_STAT_INC(out_slow_tot);
2177
2178 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2179 if (flags & RTCF_LOCAL &&
2180 !(dev_out->flags & IFF_LOOPBACK)) {
2181 rth->dst.output = ip_mc_output;
2182 RT_CACHE_STAT_INC(out_slow_mc);
2183 }
2184 #ifdef CONFIG_IP_MROUTE
2185 if (type == RTN_MULTICAST) {
2186 if (IN_DEV_MFORWARD(in_dev) &&
2187 !ipv4_is_local_multicast(fl4->daddr)) {
2188 rth->dst.input = ip_mr_input;
2189 rth->dst.output = ip_mc_output;
2190 }
2191 }
2192 #endif
2193 }
2194
2195 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2196 set_lwt_redirect(rth);
2197
2198 return rth;
2199 }
2200
2201 /*
2202 * Major route resolver routine.
2203 */
2204
2205 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2206 int mp_hash)
2207 {
2208 struct net_device *dev_out = NULL;
2209 __u8 tos = RT_FL_TOS(fl4);
2210 unsigned int flags = 0;
2211 struct fib_result res;
2212 struct rtable *rth;
2213 int orig_oif;
2214 int err = -ENETUNREACH;
2215
2216 res.tclassid = 0;
2217 res.fi = NULL;
2218 res.table = NULL;
2219
2220 orig_oif = fl4->flowi4_oif;
2221
2222 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2223 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2224 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2225 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2226
2227 rcu_read_lock();
2228 if (fl4->saddr) {
2229 rth = ERR_PTR(-EINVAL);
2230 if (ipv4_is_multicast(fl4->saddr) ||
2231 ipv4_is_lbcast(fl4->saddr) ||
2232 ipv4_is_zeronet(fl4->saddr))
2233 goto out;
2234
2235 /* I removed check for oif == dev_out->oif here.
2236 It was wrong for two reasons:
2237 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2238 is assigned to multiple interfaces.
2239 2. Moreover, we are allowed to send packets with saddr
2240 of another iface. --ANK
2241 */
2242
2243 if (fl4->flowi4_oif == 0 &&
2244 (ipv4_is_multicast(fl4->daddr) ||
2245 ipv4_is_lbcast(fl4->daddr))) {
2246 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2247 dev_out = __ip_dev_find(net, fl4->saddr, false);
2248 if (!dev_out)
2249 goto out;
2250
2251 /* Special hack: user can direct multicasts
2252 and limited broadcast via necessary interface
2253 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2254 This hack is not just for fun, it allows
2255 vic,vat and friends to work.
2256 They bind socket to loopback, set ttl to zero
2257 and expect that it will work.
2258 From the viewpoint of routing cache they are broken,
2259 because we are not allowed to build multicast path
2260 with loopback source addr (look, routing cache
2261 cannot know, that ttl is zero, so that packet
2262 will not leave this host and route is valid).
2263 Luckily, this hack is good workaround.
2264 */
2265
2266 fl4->flowi4_oif = dev_out->ifindex;
2267 goto make_route;
2268 }
2269
2270 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2271 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2272 if (!__ip_dev_find(net, fl4->saddr, false))
2273 goto out;
2274 }
2275 }
2276
2277
2278 if (fl4->flowi4_oif) {
2279 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2280 rth = ERR_PTR(-ENODEV);
2281 if (!dev_out)
2282 goto out;
2283
2284 /* RACE: Check return value of inet_select_addr instead. */
2285 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2286 rth = ERR_PTR(-ENETUNREACH);
2287 goto out;
2288 }
2289 if (ipv4_is_local_multicast(fl4->daddr) ||
2290 ipv4_is_lbcast(fl4->daddr) ||
2291 fl4->flowi4_proto == IPPROTO_IGMP) {
2292 if (!fl4->saddr)
2293 fl4->saddr = inet_select_addr(dev_out, 0,
2294 RT_SCOPE_LINK);
2295 goto make_route;
2296 }
2297 if (!fl4->saddr) {
2298 if (ipv4_is_multicast(fl4->daddr))
2299 fl4->saddr = inet_select_addr(dev_out, 0,
2300 fl4->flowi4_scope);
2301 else if (!fl4->daddr)
2302 fl4->saddr = inet_select_addr(dev_out, 0,
2303 RT_SCOPE_HOST);
2304 }
2305 }
2306
2307 if (!fl4->daddr) {
2308 fl4->daddr = fl4->saddr;
2309 if (!fl4->daddr)
2310 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2311 dev_out = net->loopback_dev;
2312 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2313 res.type = RTN_LOCAL;
2314 flags |= RTCF_LOCAL;
2315 goto make_route;
2316 }
2317
2318 err = fib_lookup(net, fl4, &res, 0);
2319 if (err) {
2320 res.fi = NULL;
2321 res.table = NULL;
2322 if (fl4->flowi4_oif &&
2323 (ipv4_is_multicast(fl4->daddr) ||
2324 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2325 /* Apparently, routing tables are wrong. Assume,
2326 that the destination is on link.
2327
2328 WHY? DW.
2329 Because we are allowed to send to iface
2330 even if it has NO routes and NO assigned
2331 addresses. When oif is specified, routing
2332 tables are looked up with only one purpose:
2333 to catch if destination is gatewayed, rather than
2334 direct. Moreover, if MSG_DONTROUTE is set,
2335 we send packet, ignoring both routing tables
2336 and ifaddr state. --ANK
2337
2338
2339 We could make it even if oif is unknown,
2340 likely IPv6, but we do not.
2341 */
2342
2343 if (fl4->saddr == 0)
2344 fl4->saddr = inet_select_addr(dev_out, 0,
2345 RT_SCOPE_LINK);
2346 res.type = RTN_UNICAST;
2347 goto make_route;
2348 }
2349 rth = ERR_PTR(err);
2350 goto out;
2351 }
2352
2353 if (res.type == RTN_LOCAL) {
2354 if (!fl4->saddr) {
2355 if (res.fi->fib_prefsrc)
2356 fl4->saddr = res.fi->fib_prefsrc;
2357 else
2358 fl4->saddr = fl4->daddr;
2359 }
2360
2361 /* L3 master device is the loopback for that domain */
2362 dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev;
2363 fl4->flowi4_oif = dev_out->ifindex;
2364 flags |= RTCF_LOCAL;
2365 goto make_route;
2366 }
2367
2368 fib_select_path(net, &res, fl4, mp_hash);
2369
2370 dev_out = FIB_RES_DEV(res);
2371 fl4->flowi4_oif = dev_out->ifindex;
2372
2373
2374 make_route:
2375 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2376
2377 out:
2378 rcu_read_unlock();
2379 return rth;
2380 }
2381 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2382
2383 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2384 {
2385 return NULL;
2386 }
2387
2388 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2389 {
2390 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2391
2392 return mtu ? : dst->dev->mtu;
2393 }
2394
2395 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2396 struct sk_buff *skb, u32 mtu)
2397 {
2398 }
2399
2400 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2401 struct sk_buff *skb)
2402 {
2403 }
2404
2405 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2406 unsigned long old)
2407 {
2408 return NULL;
2409 }
2410
2411 static struct dst_ops ipv4_dst_blackhole_ops = {
2412 .family = AF_INET,
2413 .check = ipv4_blackhole_dst_check,
2414 .mtu = ipv4_blackhole_mtu,
2415 .default_advmss = ipv4_default_advmss,
2416 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2417 .redirect = ipv4_rt_blackhole_redirect,
2418 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2419 .neigh_lookup = ipv4_neigh_lookup,
2420 };
2421
2422 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2423 {
2424 struct rtable *ort = (struct rtable *) dst_orig;
2425 struct rtable *rt;
2426
2427 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2428 if (rt) {
2429 struct dst_entry *new = &rt->dst;
2430
2431 new->__use = 1;
2432 new->input = dst_discard;
2433 new->output = dst_discard_out;
2434
2435 new->dev = ort->dst.dev;
2436 if (new->dev)
2437 dev_hold(new->dev);
2438
2439 rt->rt_is_input = ort->rt_is_input;
2440 rt->rt_iif = ort->rt_iif;
2441 rt->rt_pmtu = ort->rt_pmtu;
2442
2443 rt->rt_genid = rt_genid_ipv4(net);
2444 rt->rt_flags = ort->rt_flags;
2445 rt->rt_type = ort->rt_type;
2446 rt->rt_gateway = ort->rt_gateway;
2447 rt->rt_uses_gateway = ort->rt_uses_gateway;
2448
2449 INIT_LIST_HEAD(&rt->rt_uncached);
2450 dst_free(new);
2451 }
2452
2453 dst_release(dst_orig);
2454
2455 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2456 }
2457
2458 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2459 const struct sock *sk)
2460 {
2461 struct rtable *rt = __ip_route_output_key(net, flp4);
2462
2463 if (IS_ERR(rt))
2464 return rt;
2465
2466 if (flp4->flowi4_proto)
2467 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2468 flowi4_to_flowi(flp4),
2469 sk, 0);
2470
2471 return rt;
2472 }
2473 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2474
2475 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2476 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2477 u32 seq, int event)
2478 {
2479 struct rtable *rt = skb_rtable(skb);
2480 struct rtmsg *r;
2481 struct nlmsghdr *nlh;
2482 unsigned long expires = 0;
2483 u32 error;
2484 u32 metrics[RTAX_MAX];
2485
2486 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), 0);
2487 if (!nlh)
2488 return -EMSGSIZE;
2489
2490 r = nlmsg_data(nlh);
2491 r->rtm_family = AF_INET;
2492 r->rtm_dst_len = 32;
2493 r->rtm_src_len = 0;
2494 r->rtm_tos = fl4->flowi4_tos;
2495 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2496 if (nla_put_u32(skb, RTA_TABLE, table_id))
2497 goto nla_put_failure;
2498 r->rtm_type = rt->rt_type;
2499 r->rtm_scope = RT_SCOPE_UNIVERSE;
2500 r->rtm_protocol = RTPROT_UNSPEC;
2501 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2502 if (rt->rt_flags & RTCF_NOTIFY)
2503 r->rtm_flags |= RTM_F_NOTIFY;
2504 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2505 r->rtm_flags |= RTCF_DOREDIRECT;
2506
2507 if (nla_put_in_addr(skb, RTA_DST, dst))
2508 goto nla_put_failure;
2509 if (src) {
2510 r->rtm_src_len = 32;
2511 if (nla_put_in_addr(skb, RTA_SRC, src))
2512 goto nla_put_failure;
2513 }
2514 if (rt->dst.dev &&
2515 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2516 goto nla_put_failure;
2517 #ifdef CONFIG_IP_ROUTE_CLASSID
2518 if (rt->dst.tclassid &&
2519 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2520 goto nla_put_failure;
2521 #endif
2522 if (!rt_is_input_route(rt) &&
2523 fl4->saddr != src) {
2524 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2525 goto nla_put_failure;
2526 }
2527 if (rt->rt_uses_gateway &&
2528 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2529 goto nla_put_failure;
2530
2531 expires = rt->dst.expires;
2532 if (expires) {
2533 unsigned long now = jiffies;
2534
2535 if (time_before(now, expires))
2536 expires -= now;
2537 else
2538 expires = 0;
2539 }
2540
2541 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2542 if (rt->rt_pmtu && expires)
2543 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2544 if (rtnetlink_put_metrics(skb, metrics) < 0)
2545 goto nla_put_failure;
2546
2547 if (fl4->flowi4_mark &&
2548 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2549 goto nla_put_failure;
2550
2551 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2552 nla_put_u32(skb, RTA_UID,
2553 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2554 goto nla_put_failure;
2555
2556 error = rt->dst.error;
2557
2558 if (rt_is_input_route(rt)) {
2559 #ifdef CONFIG_IP_MROUTE
2560 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2561 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2562 int err = ipmr_get_route(net, skb,
2563 fl4->saddr, fl4->daddr,
2564 r, portid);
2565
2566 if (err <= 0) {
2567 if (err == 0)
2568 return 0;
2569 goto nla_put_failure;
2570 }
2571 } else
2572 #endif
2573 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2574 goto nla_put_failure;
2575 }
2576
2577 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2578 goto nla_put_failure;
2579
2580 nlmsg_end(skb, nlh);
2581 return 0;
2582
2583 nla_put_failure:
2584 nlmsg_cancel(skb, nlh);
2585 return -EMSGSIZE;
2586 }
2587
2588 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2589 {
2590 struct net *net = sock_net(in_skb->sk);
2591 struct rtmsg *rtm;
2592 struct nlattr *tb[RTA_MAX+1];
2593 struct rtable *rt = NULL;
2594 struct flowi4 fl4;
2595 __be32 dst = 0;
2596 __be32 src = 0;
2597 u32 iif;
2598 int err;
2599 int mark;
2600 struct sk_buff *skb;
2601 u32 table_id = RT_TABLE_MAIN;
2602 kuid_t uid;
2603
2604 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2605 if (err < 0)
2606 goto errout;
2607
2608 rtm = nlmsg_data(nlh);
2609
2610 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2611 if (!skb) {
2612 err = -ENOBUFS;
2613 goto errout;
2614 }
2615
2616 /* Reserve room for dummy headers, this skb can pass
2617 through good chunk of routing engine.
2618 */
2619 skb_reset_mac_header(skb);
2620 skb_reset_network_header(skb);
2621
2622 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2623 ip_hdr(skb)->protocol = IPPROTO_UDP;
2624 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2625
2626 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2627 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2628 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2629 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2630 if (tb[RTA_UID])
2631 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2632 else
2633 uid = (iif ? INVALID_UID : current_uid());
2634
2635 memset(&fl4, 0, sizeof(fl4));
2636 fl4.daddr = dst;
2637 fl4.saddr = src;
2638 fl4.flowi4_tos = rtm->rtm_tos;
2639 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2640 fl4.flowi4_mark = mark;
2641 fl4.flowi4_uid = uid;
2642
2643 if (iif) {
2644 struct net_device *dev;
2645
2646 dev = __dev_get_by_index(net, iif);
2647 if (!dev) {
2648 err = -ENODEV;
2649 goto errout_free;
2650 }
2651
2652 skb->protocol = htons(ETH_P_IP);
2653 skb->dev = dev;
2654 skb->mark = mark;
2655 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2656
2657 rt = skb_rtable(skb);
2658 if (err == 0 && rt->dst.error)
2659 err = -rt->dst.error;
2660 } else {
2661 rt = ip_route_output_key(net, &fl4);
2662
2663 err = 0;
2664 if (IS_ERR(rt))
2665 err = PTR_ERR(rt);
2666 }
2667
2668 if (err)
2669 goto errout_free;
2670
2671 skb_dst_set(skb, &rt->dst);
2672 if (rtm->rtm_flags & RTM_F_NOTIFY)
2673 rt->rt_flags |= RTCF_NOTIFY;
2674
2675 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2676 table_id = rt->rt_table_id;
2677
2678 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2679 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2680 RTM_NEWROUTE);
2681 if (err < 0)
2682 goto errout_free;
2683
2684 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2685 errout:
2686 return err;
2687
2688 errout_free:
2689 kfree_skb(skb);
2690 goto errout;
2691 }
2692
2693 void ip_rt_multicast_event(struct in_device *in_dev)
2694 {
2695 rt_cache_flush(dev_net(in_dev->dev));
2696 }
2697
2698 #ifdef CONFIG_SYSCTL
2699 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2700 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2701 static int ip_rt_gc_elasticity __read_mostly = 8;
2702
2703 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2704 void __user *buffer,
2705 size_t *lenp, loff_t *ppos)
2706 {
2707 struct net *net = (struct net *)__ctl->extra1;
2708
2709 if (write) {
2710 rt_cache_flush(net);
2711 fnhe_genid_bump(net);
2712 return 0;
2713 }
2714
2715 return -EINVAL;
2716 }
2717
2718 static struct ctl_table ipv4_route_table[] = {
2719 {
2720 .procname = "gc_thresh",
2721 .data = &ipv4_dst_ops.gc_thresh,
2722 .maxlen = sizeof(int),
2723 .mode = 0644,
2724 .proc_handler = proc_dointvec,
2725 },
2726 {
2727 .procname = "max_size",
2728 .data = &ip_rt_max_size,
2729 .maxlen = sizeof(int),
2730 .mode = 0644,
2731 .proc_handler = proc_dointvec,
2732 },
2733 {
2734 /* Deprecated. Use gc_min_interval_ms */
2735
2736 .procname = "gc_min_interval",
2737 .data = &ip_rt_gc_min_interval,
2738 .maxlen = sizeof(int),
2739 .mode = 0644,
2740 .proc_handler = proc_dointvec_jiffies,
2741 },
2742 {
2743 .procname = "gc_min_interval_ms",
2744 .data = &ip_rt_gc_min_interval,
2745 .maxlen = sizeof(int),
2746 .mode = 0644,
2747 .proc_handler = proc_dointvec_ms_jiffies,
2748 },
2749 {
2750 .procname = "gc_timeout",
2751 .data = &ip_rt_gc_timeout,
2752 .maxlen = sizeof(int),
2753 .mode = 0644,
2754 .proc_handler = proc_dointvec_jiffies,
2755 },
2756 {
2757 .procname = "gc_interval",
2758 .data = &ip_rt_gc_interval,
2759 .maxlen = sizeof(int),
2760 .mode = 0644,
2761 .proc_handler = proc_dointvec_jiffies,
2762 },
2763 {
2764 .procname = "redirect_load",
2765 .data = &ip_rt_redirect_load,
2766 .maxlen = sizeof(int),
2767 .mode = 0644,
2768 .proc_handler = proc_dointvec,
2769 },
2770 {
2771 .procname = "redirect_number",
2772 .data = &ip_rt_redirect_number,
2773 .maxlen = sizeof(int),
2774 .mode = 0644,
2775 .proc_handler = proc_dointvec,
2776 },
2777 {
2778 .procname = "redirect_silence",
2779 .data = &ip_rt_redirect_silence,
2780 .maxlen = sizeof(int),
2781 .mode = 0644,
2782 .proc_handler = proc_dointvec,
2783 },
2784 {
2785 .procname = "error_cost",
2786 .data = &ip_rt_error_cost,
2787 .maxlen = sizeof(int),
2788 .mode = 0644,
2789 .proc_handler = proc_dointvec,
2790 },
2791 {
2792 .procname = "error_burst",
2793 .data = &ip_rt_error_burst,
2794 .maxlen = sizeof(int),
2795 .mode = 0644,
2796 .proc_handler = proc_dointvec,
2797 },
2798 {
2799 .procname = "gc_elasticity",
2800 .data = &ip_rt_gc_elasticity,
2801 .maxlen = sizeof(int),
2802 .mode = 0644,
2803 .proc_handler = proc_dointvec,
2804 },
2805 {
2806 .procname = "mtu_expires",
2807 .data = &ip_rt_mtu_expires,
2808 .maxlen = sizeof(int),
2809 .mode = 0644,
2810 .proc_handler = proc_dointvec_jiffies,
2811 },
2812 {
2813 .procname = "min_pmtu",
2814 .data = &ip_rt_min_pmtu,
2815 .maxlen = sizeof(int),
2816 .mode = 0644,
2817 .proc_handler = proc_dointvec,
2818 },
2819 {
2820 .procname = "min_adv_mss",
2821 .data = &ip_rt_min_advmss,
2822 .maxlen = sizeof(int),
2823 .mode = 0644,
2824 .proc_handler = proc_dointvec,
2825 },
2826 { }
2827 };
2828
2829 static struct ctl_table ipv4_route_flush_table[] = {
2830 {
2831 .procname = "flush",
2832 .maxlen = sizeof(int),
2833 .mode = 0200,
2834 .proc_handler = ipv4_sysctl_rtcache_flush,
2835 },
2836 { },
2837 };
2838
2839 static __net_init int sysctl_route_net_init(struct net *net)
2840 {
2841 struct ctl_table *tbl;
2842
2843 tbl = ipv4_route_flush_table;
2844 if (!net_eq(net, &init_net)) {
2845 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2846 if (!tbl)
2847 goto err_dup;
2848
2849 /* Don't export sysctls to unprivileged users */
2850 if (net->user_ns != &init_user_ns)
2851 tbl[0].procname = NULL;
2852 }
2853 tbl[0].extra1 = net;
2854
2855 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2856 if (!net->ipv4.route_hdr)
2857 goto err_reg;
2858 return 0;
2859
2860 err_reg:
2861 if (tbl != ipv4_route_flush_table)
2862 kfree(tbl);
2863 err_dup:
2864 return -ENOMEM;
2865 }
2866
2867 static __net_exit void sysctl_route_net_exit(struct net *net)
2868 {
2869 struct ctl_table *tbl;
2870
2871 tbl = net->ipv4.route_hdr->ctl_table_arg;
2872 unregister_net_sysctl_table(net->ipv4.route_hdr);
2873 BUG_ON(tbl == ipv4_route_flush_table);
2874 kfree(tbl);
2875 }
2876
2877 static __net_initdata struct pernet_operations sysctl_route_ops = {
2878 .init = sysctl_route_net_init,
2879 .exit = sysctl_route_net_exit,
2880 };
2881 #endif
2882
2883 static __net_init int rt_genid_init(struct net *net)
2884 {
2885 atomic_set(&net->ipv4.rt_genid, 0);
2886 atomic_set(&net->fnhe_genid, 0);
2887 get_random_bytes(&net->ipv4.dev_addr_genid,
2888 sizeof(net->ipv4.dev_addr_genid));
2889 return 0;
2890 }
2891
2892 static __net_initdata struct pernet_operations rt_genid_ops = {
2893 .init = rt_genid_init,
2894 };
2895
2896 static int __net_init ipv4_inetpeer_init(struct net *net)
2897 {
2898 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2899
2900 if (!bp)
2901 return -ENOMEM;
2902 inet_peer_base_init(bp);
2903 net->ipv4.peers = bp;
2904 return 0;
2905 }
2906
2907 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2908 {
2909 struct inet_peer_base *bp = net->ipv4.peers;
2910
2911 net->ipv4.peers = NULL;
2912 inetpeer_invalidate_tree(bp);
2913 kfree(bp);
2914 }
2915
2916 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2917 .init = ipv4_inetpeer_init,
2918 .exit = ipv4_inetpeer_exit,
2919 };
2920
2921 #ifdef CONFIG_IP_ROUTE_CLASSID
2922 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2923 #endif /* CONFIG_IP_ROUTE_CLASSID */
2924
2925 int __init ip_rt_init(void)
2926 {
2927 int rc = 0;
2928 int cpu;
2929
2930 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2931 if (!ip_idents)
2932 panic("IP: failed to allocate ip_idents\n");
2933
2934 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2935
2936 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2937 if (!ip_tstamps)
2938 panic("IP: failed to allocate ip_tstamps\n");
2939
2940 for_each_possible_cpu(cpu) {
2941 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2942
2943 INIT_LIST_HEAD(&ul->head);
2944 spin_lock_init(&ul->lock);
2945 }
2946 #ifdef CONFIG_IP_ROUTE_CLASSID
2947 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2948 if (!ip_rt_acct)
2949 panic("IP: failed to allocate ip_rt_acct\n");
2950 #endif
2951
2952 ipv4_dst_ops.kmem_cachep =
2953 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2954 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2955
2956 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2957
2958 if (dst_entries_init(&ipv4_dst_ops) < 0)
2959 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2960
2961 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2962 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2963
2964 ipv4_dst_ops.gc_thresh = ~0;
2965 ip_rt_max_size = INT_MAX;
2966
2967 devinet_init();
2968 ip_fib_init();
2969
2970 if (ip_rt_proc_init())
2971 pr_err("Unable to create route proc files\n");
2972 #ifdef CONFIG_XFRM
2973 xfrm_init();
2974 xfrm4_init();
2975 #endif
2976 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2977
2978 #ifdef CONFIG_SYSCTL
2979 register_pernet_subsys(&sysctl_route_ops);
2980 #endif
2981 register_pernet_subsys(&rt_genid_ops);
2982 register_pernet_subsys(&ipv4_inetpeer_ops);
2983 return rc;
2984 }
2985
2986 #ifdef CONFIG_SYSCTL
2987 /*
2988 * We really need to sanitize the damn ipv4 init order, then all
2989 * this nonsense will go away.
2990 */
2991 void __init ip_static_sysctl_init(void)
2992 {
2993 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2994 }
2995 #endif
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