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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
[mirror_ubuntu-zesty-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
158 static struct dst_ops ipv4_dst_ops = {
159 .family = AF_INET,
160 .check = ipv4_dst_check,
161 .default_advmss = ipv4_default_advmss,
162 .mtu = ipv4_mtu,
163 .cow_metrics = ipv4_cow_metrics,
164 .destroy = ipv4_dst_destroy,
165 .negative_advice = ipv4_negative_advice,
166 .link_failure = ipv4_link_failure,
167 .update_pmtu = ip_rt_update_pmtu,
168 .redirect = ip_do_redirect,
169 .local_out = __ip_local_out,
170 .neigh_lookup = ipv4_neigh_lookup,
171 };
172
173 #define ECN_OR_COST(class) TC_PRIO_##class
174
175 const __u8 ip_tos2prio[16] = {
176 TC_PRIO_BESTEFFORT,
177 ECN_OR_COST(BESTEFFORT),
178 TC_PRIO_BESTEFFORT,
179 ECN_OR_COST(BESTEFFORT),
180 TC_PRIO_BULK,
181 ECN_OR_COST(BULK),
182 TC_PRIO_BULK,
183 ECN_OR_COST(BULK),
184 TC_PRIO_INTERACTIVE,
185 ECN_OR_COST(INTERACTIVE),
186 TC_PRIO_INTERACTIVE,
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE_BULK,
189 ECN_OR_COST(INTERACTIVE_BULK),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK)
192 };
193 EXPORT_SYMBOL(ip_tos2prio);
194
195 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
196 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
197
198 #ifdef CONFIG_PROC_FS
199 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
200 {
201 if (*pos)
202 return NULL;
203 return SEQ_START_TOKEN;
204 }
205
206 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
207 {
208 ++*pos;
209 return NULL;
210 }
211
212 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
213 {
214 }
215
216 static int rt_cache_seq_show(struct seq_file *seq, void *v)
217 {
218 if (v == SEQ_START_TOKEN)
219 seq_printf(seq, "%-127s\n",
220 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
221 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
222 "HHUptod\tSpecDst");
223 return 0;
224 }
225
226 static const struct seq_operations rt_cache_seq_ops = {
227 .start = rt_cache_seq_start,
228 .next = rt_cache_seq_next,
229 .stop = rt_cache_seq_stop,
230 .show = rt_cache_seq_show,
231 };
232
233 static int rt_cache_seq_open(struct inode *inode, struct file *file)
234 {
235 return seq_open(file, &rt_cache_seq_ops);
236 }
237
238 static const struct file_operations rt_cache_seq_fops = {
239 .owner = THIS_MODULE,
240 .open = rt_cache_seq_open,
241 .read = seq_read,
242 .llseek = seq_lseek,
243 .release = seq_release,
244 };
245
246
247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
248 {
249 int cpu;
250
251 if (*pos == 0)
252 return SEQ_START_TOKEN;
253
254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
255 if (!cpu_possible(cpu))
256 continue;
257 *pos = cpu+1;
258 return &per_cpu(rt_cache_stat, cpu);
259 }
260 return NULL;
261 }
262
263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
264 {
265 int cpu;
266
267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
268 if (!cpu_possible(cpu))
269 continue;
270 *pos = cpu+1;
271 return &per_cpu(rt_cache_stat, cpu);
272 }
273 return NULL;
274
275 }
276
277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
278 {
279
280 }
281
282 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
283 {
284 struct rt_cache_stat *st = v;
285
286 if (v == SEQ_START_TOKEN) {
287 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");
288 return 0;
289 }
290
291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
293 dst_entries_get_slow(&ipv4_dst_ops),
294 0, /* st->in_hit */
295 st->in_slow_tot,
296 st->in_slow_mc,
297 st->in_no_route,
298 st->in_brd,
299 st->in_martian_dst,
300 st->in_martian_src,
301
302 0, /* st->out_hit */
303 st->out_slow_tot,
304 st->out_slow_mc,
305
306 0, /* st->gc_total */
307 0, /* st->gc_ignored */
308 0, /* st->gc_goal_miss */
309 0, /* st->gc_dst_overflow */
310 0, /* st->in_hlist_search */
311 0 /* st->out_hlist_search */
312 );
313 return 0;
314 }
315
316 static const struct seq_operations rt_cpu_seq_ops = {
317 .start = rt_cpu_seq_start,
318 .next = rt_cpu_seq_next,
319 .stop = rt_cpu_seq_stop,
320 .show = rt_cpu_seq_show,
321 };
322
323
324 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
325 {
326 return seq_open(file, &rt_cpu_seq_ops);
327 }
328
329 static const struct file_operations rt_cpu_seq_fops = {
330 .owner = THIS_MODULE,
331 .open = rt_cpu_seq_open,
332 .read = seq_read,
333 .llseek = seq_lseek,
334 .release = seq_release,
335 };
336
337 #ifdef CONFIG_IP_ROUTE_CLASSID
338 static int rt_acct_proc_show(struct seq_file *m, void *v)
339 {
340 struct ip_rt_acct *dst, *src;
341 unsigned int i, j;
342
343 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
344 if (!dst)
345 return -ENOMEM;
346
347 for_each_possible_cpu(i) {
348 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
349 for (j = 0; j < 256; j++) {
350 dst[j].o_bytes += src[j].o_bytes;
351 dst[j].o_packets += src[j].o_packets;
352 dst[j].i_bytes += src[j].i_bytes;
353 dst[j].i_packets += src[j].i_packets;
354 }
355 }
356
357 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
358 kfree(dst);
359 return 0;
360 }
361
362 static int rt_acct_proc_open(struct inode *inode, struct file *file)
363 {
364 return single_open(file, rt_acct_proc_show, NULL);
365 }
366
367 static const struct file_operations rt_acct_proc_fops = {
368 .owner = THIS_MODULE,
369 .open = rt_acct_proc_open,
370 .read = seq_read,
371 .llseek = seq_lseek,
372 .release = single_release,
373 };
374 #endif
375
376 static int __net_init ip_rt_do_proc_init(struct net *net)
377 {
378 struct proc_dir_entry *pde;
379
380 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
381 &rt_cache_seq_fops);
382 if (!pde)
383 goto err1;
384
385 pde = proc_create("rt_cache", S_IRUGO,
386 net->proc_net_stat, &rt_cpu_seq_fops);
387 if (!pde)
388 goto err2;
389
390 #ifdef CONFIG_IP_ROUTE_CLASSID
391 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
392 if (!pde)
393 goto err3;
394 #endif
395 return 0;
396
397 #ifdef CONFIG_IP_ROUTE_CLASSID
398 err3:
399 remove_proc_entry("rt_cache", net->proc_net_stat);
400 #endif
401 err2:
402 remove_proc_entry("rt_cache", net->proc_net);
403 err1:
404 return -ENOMEM;
405 }
406
407 static void __net_exit ip_rt_do_proc_exit(struct net *net)
408 {
409 remove_proc_entry("rt_cache", net->proc_net_stat);
410 remove_proc_entry("rt_cache", net->proc_net);
411 #ifdef CONFIG_IP_ROUTE_CLASSID
412 remove_proc_entry("rt_acct", net->proc_net);
413 #endif
414 }
415
416 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
417 .init = ip_rt_do_proc_init,
418 .exit = ip_rt_do_proc_exit,
419 };
420
421 static int __init ip_rt_proc_init(void)
422 {
423 return register_pernet_subsys(&ip_rt_proc_ops);
424 }
425
426 #else
427 static inline int ip_rt_proc_init(void)
428 {
429 return 0;
430 }
431 #endif /* CONFIG_PROC_FS */
432
433 static inline bool rt_is_expired(const struct rtable *rth)
434 {
435 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
436 }
437
438 void rt_cache_flush(struct net *net)
439 {
440 rt_genid_bump_ipv4(net);
441 }
442
443 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
444 struct sk_buff *skb,
445 const void *daddr)
446 {
447 struct net_device *dev = dst->dev;
448 const __be32 *pkey = daddr;
449 const struct rtable *rt;
450 struct neighbour *n;
451
452 rt = (const struct rtable *) dst;
453 if (rt->rt_gateway)
454 pkey = (const __be32 *) &rt->rt_gateway;
455 else if (skb)
456 pkey = &ip_hdr(skb)->daddr;
457
458 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
459 if (n)
460 return n;
461 return neigh_create(&arp_tbl, pkey, dev);
462 }
463
464 #define IP_IDENTS_SZ 2048u
465
466 static atomic_t *ip_idents __read_mostly;
467 static u32 *ip_tstamps __read_mostly;
468
469 /* In order to protect privacy, we add a perturbation to identifiers
470 * if one generator is seldom used. This makes hard for an attacker
471 * to infer how many packets were sent between two points in time.
472 */
473 u32 ip_idents_reserve(u32 hash, int segs)
474 {
475 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
476 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
477 u32 old = ACCESS_ONCE(*p_tstamp);
478 u32 now = (u32)jiffies;
479 u32 new, delta = 0;
480
481 if (old != now && cmpxchg(p_tstamp, old, now) == old)
482 delta = prandom_u32_max(now - old);
483
484 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
485 do {
486 old = (u32)atomic_read(p_id);
487 new = old + delta + segs;
488 } while (atomic_cmpxchg(p_id, old, new) != old);
489
490 return new - segs;
491 }
492 EXPORT_SYMBOL(ip_idents_reserve);
493
494 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
495 {
496 static u32 ip_idents_hashrnd __read_mostly;
497 u32 hash, id;
498
499 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
500
501 hash = jhash_3words((__force u32)iph->daddr,
502 (__force u32)iph->saddr,
503 iph->protocol ^ net_hash_mix(net),
504 ip_idents_hashrnd);
505 id = ip_idents_reserve(hash, segs);
506 iph->id = htons(id);
507 }
508 EXPORT_SYMBOL(__ip_select_ident);
509
510 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
511 const struct sock *sk,
512 const struct iphdr *iph,
513 int oif, u8 tos,
514 u8 prot, u32 mark, int flow_flags)
515 {
516 if (sk) {
517 const struct inet_sock *inet = inet_sk(sk);
518
519 oif = sk->sk_bound_dev_if;
520 mark = sk->sk_mark;
521 tos = RT_CONN_FLAGS(sk);
522 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
523 }
524 flowi4_init_output(fl4, oif, mark, tos,
525 RT_SCOPE_UNIVERSE, prot,
526 flow_flags,
527 iph->daddr, iph->saddr, 0, 0,
528 sock_net_uid(net, sk));
529 }
530
531 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
532 const struct sock *sk)
533 {
534 const struct net *net = dev_net(skb->dev);
535 const struct iphdr *iph = ip_hdr(skb);
536 int oif = skb->dev->ifindex;
537 u8 tos = RT_TOS(iph->tos);
538 u8 prot = iph->protocol;
539 u32 mark = skb->mark;
540
541 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
542 }
543
544 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
545 {
546 const struct inet_sock *inet = inet_sk(sk);
547 const struct ip_options_rcu *inet_opt;
548 __be32 daddr = inet->inet_daddr;
549
550 rcu_read_lock();
551 inet_opt = rcu_dereference(inet->inet_opt);
552 if (inet_opt && inet_opt->opt.srr)
553 daddr = inet_opt->opt.faddr;
554 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
555 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
556 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
557 inet_sk_flowi_flags(sk),
558 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
559 rcu_read_unlock();
560 }
561
562 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
563 const struct sk_buff *skb)
564 {
565 if (skb)
566 build_skb_flow_key(fl4, skb, sk);
567 else
568 build_sk_flow_key(fl4, sk);
569 }
570
571 static inline void rt_free(struct rtable *rt)
572 {
573 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
574 }
575
576 static DEFINE_SPINLOCK(fnhe_lock);
577
578 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
579 {
580 struct rtable *rt;
581
582 rt = rcu_dereference(fnhe->fnhe_rth_input);
583 if (rt) {
584 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
585 rt_free(rt);
586 }
587 rt = rcu_dereference(fnhe->fnhe_rth_output);
588 if (rt) {
589 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
590 rt_free(rt);
591 }
592 }
593
594 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
595 {
596 struct fib_nh_exception *fnhe, *oldest;
597
598 oldest = rcu_dereference(hash->chain);
599 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
600 fnhe = rcu_dereference(fnhe->fnhe_next)) {
601 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
602 oldest = fnhe;
603 }
604 fnhe_flush_routes(oldest);
605 return oldest;
606 }
607
608 static inline u32 fnhe_hashfun(__be32 daddr)
609 {
610 static u32 fnhe_hashrnd __read_mostly;
611 u32 hval;
612
613 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
614 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
615 return hash_32(hval, FNHE_HASH_SHIFT);
616 }
617
618 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
619 {
620 rt->rt_pmtu = fnhe->fnhe_pmtu;
621 rt->dst.expires = fnhe->fnhe_expires;
622
623 if (fnhe->fnhe_gw) {
624 rt->rt_flags |= RTCF_REDIRECTED;
625 rt->rt_gateway = fnhe->fnhe_gw;
626 rt->rt_uses_gateway = 1;
627 }
628 }
629
630 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
631 u32 pmtu, unsigned long expires)
632 {
633 struct fnhe_hash_bucket *hash;
634 struct fib_nh_exception *fnhe;
635 struct rtable *rt;
636 unsigned int i;
637 int depth;
638 u32 hval = fnhe_hashfun(daddr);
639
640 spin_lock_bh(&fnhe_lock);
641
642 hash = rcu_dereference(nh->nh_exceptions);
643 if (!hash) {
644 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
645 if (!hash)
646 goto out_unlock;
647 rcu_assign_pointer(nh->nh_exceptions, hash);
648 }
649
650 hash += hval;
651
652 depth = 0;
653 for (fnhe = rcu_dereference(hash->chain); fnhe;
654 fnhe = rcu_dereference(fnhe->fnhe_next)) {
655 if (fnhe->fnhe_daddr == daddr)
656 break;
657 depth++;
658 }
659
660 if (fnhe) {
661 if (gw)
662 fnhe->fnhe_gw = gw;
663 if (pmtu) {
664 fnhe->fnhe_pmtu = pmtu;
665 fnhe->fnhe_expires = max(1UL, expires);
666 }
667 /* Update all cached dsts too */
668 rt = rcu_dereference(fnhe->fnhe_rth_input);
669 if (rt)
670 fill_route_from_fnhe(rt, fnhe);
671 rt = rcu_dereference(fnhe->fnhe_rth_output);
672 if (rt)
673 fill_route_from_fnhe(rt, fnhe);
674 } else {
675 if (depth > FNHE_RECLAIM_DEPTH)
676 fnhe = fnhe_oldest(hash);
677 else {
678 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
679 if (!fnhe)
680 goto out_unlock;
681
682 fnhe->fnhe_next = hash->chain;
683 rcu_assign_pointer(hash->chain, fnhe);
684 }
685 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
686 fnhe->fnhe_daddr = daddr;
687 fnhe->fnhe_gw = gw;
688 fnhe->fnhe_pmtu = pmtu;
689 fnhe->fnhe_expires = expires;
690
691 /* Exception created; mark the cached routes for the nexthop
692 * stale, so anyone caching it rechecks if this exception
693 * applies to them.
694 */
695 rt = rcu_dereference(nh->nh_rth_input);
696 if (rt)
697 rt->dst.obsolete = DST_OBSOLETE_KILL;
698
699 for_each_possible_cpu(i) {
700 struct rtable __rcu **prt;
701 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
702 rt = rcu_dereference(*prt);
703 if (rt)
704 rt->dst.obsolete = DST_OBSOLETE_KILL;
705 }
706 }
707
708 fnhe->fnhe_stamp = jiffies;
709
710 out_unlock:
711 spin_unlock_bh(&fnhe_lock);
712 }
713
714 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
715 bool kill_route)
716 {
717 __be32 new_gw = icmp_hdr(skb)->un.gateway;
718 __be32 old_gw = ip_hdr(skb)->saddr;
719 struct net_device *dev = skb->dev;
720 struct in_device *in_dev;
721 struct fib_result res;
722 struct neighbour *n;
723 struct net *net;
724
725 switch (icmp_hdr(skb)->code & 7) {
726 case ICMP_REDIR_NET:
727 case ICMP_REDIR_NETTOS:
728 case ICMP_REDIR_HOST:
729 case ICMP_REDIR_HOSTTOS:
730 break;
731
732 default:
733 return;
734 }
735
736 if (rt->rt_gateway != old_gw)
737 return;
738
739 in_dev = __in_dev_get_rcu(dev);
740 if (!in_dev)
741 return;
742
743 net = dev_net(dev);
744 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
745 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
746 ipv4_is_zeronet(new_gw))
747 goto reject_redirect;
748
749 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
750 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
751 goto reject_redirect;
752 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
753 goto reject_redirect;
754 } else {
755 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
756 goto reject_redirect;
757 }
758
759 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
760 if (!n)
761 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
762 if (!IS_ERR(n)) {
763 if (!(n->nud_state & NUD_VALID)) {
764 neigh_event_send(n, NULL);
765 } else {
766 if (fib_lookup(net, fl4, &res, 0) == 0) {
767 struct fib_nh *nh = &FIB_RES_NH(res);
768
769 update_or_create_fnhe(nh, fl4->daddr, new_gw,
770 0, jiffies + ip_rt_gc_timeout);
771 }
772 if (kill_route)
773 rt->dst.obsolete = DST_OBSOLETE_KILL;
774 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
775 }
776 neigh_release(n);
777 }
778 return;
779
780 reject_redirect:
781 #ifdef CONFIG_IP_ROUTE_VERBOSE
782 if (IN_DEV_LOG_MARTIANS(in_dev)) {
783 const struct iphdr *iph = (const struct iphdr *) skb->data;
784 __be32 daddr = iph->daddr;
785 __be32 saddr = iph->saddr;
786
787 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
788 " Advised path = %pI4 -> %pI4\n",
789 &old_gw, dev->name, &new_gw,
790 &saddr, &daddr);
791 }
792 #endif
793 ;
794 }
795
796 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
797 {
798 struct rtable *rt;
799 struct flowi4 fl4;
800 const struct iphdr *iph = (const struct iphdr *) skb->data;
801 struct net *net = dev_net(skb->dev);
802 int oif = skb->dev->ifindex;
803 u8 tos = RT_TOS(iph->tos);
804 u8 prot = iph->protocol;
805 u32 mark = skb->mark;
806
807 rt = (struct rtable *) dst;
808
809 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
810 __ip_do_redirect(rt, skb, &fl4, true);
811 }
812
813 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
814 {
815 struct rtable *rt = (struct rtable *)dst;
816 struct dst_entry *ret = dst;
817
818 if (rt) {
819 if (dst->obsolete > 0) {
820 ip_rt_put(rt);
821 ret = NULL;
822 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
823 rt->dst.expires) {
824 ip_rt_put(rt);
825 ret = NULL;
826 }
827 }
828 return ret;
829 }
830
831 /*
832 * Algorithm:
833 * 1. The first ip_rt_redirect_number redirects are sent
834 * with exponential backoff, then we stop sending them at all,
835 * assuming that the host ignores our redirects.
836 * 2. If we did not see packets requiring redirects
837 * during ip_rt_redirect_silence, we assume that the host
838 * forgot redirected route and start to send redirects again.
839 *
840 * This algorithm is much cheaper and more intelligent than dumb load limiting
841 * in icmp.c.
842 *
843 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
844 * and "frag. need" (breaks PMTU discovery) in icmp.c.
845 */
846
847 void ip_rt_send_redirect(struct sk_buff *skb)
848 {
849 struct rtable *rt = skb_rtable(skb);
850 struct in_device *in_dev;
851 struct inet_peer *peer;
852 struct net *net;
853 int log_martians;
854 int vif;
855
856 rcu_read_lock();
857 in_dev = __in_dev_get_rcu(rt->dst.dev);
858 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
859 rcu_read_unlock();
860 return;
861 }
862 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
863 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
864 rcu_read_unlock();
865
866 net = dev_net(rt->dst.dev);
867 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
868 if (!peer) {
869 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
870 rt_nexthop(rt, ip_hdr(skb)->daddr));
871 return;
872 }
873
874 /* No redirected packets during ip_rt_redirect_silence;
875 * reset the algorithm.
876 */
877 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
878 peer->rate_tokens = 0;
879
880 /* Too many ignored redirects; do not send anything
881 * set dst.rate_last to the last seen redirected packet.
882 */
883 if (peer->rate_tokens >= ip_rt_redirect_number) {
884 peer->rate_last = jiffies;
885 goto out_put_peer;
886 }
887
888 /* Check for load limit; set rate_last to the latest sent
889 * redirect.
890 */
891 if (peer->rate_tokens == 0 ||
892 time_after(jiffies,
893 (peer->rate_last +
894 (ip_rt_redirect_load << peer->rate_tokens)))) {
895 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
896
897 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
898 peer->rate_last = jiffies;
899 ++peer->rate_tokens;
900 #ifdef CONFIG_IP_ROUTE_VERBOSE
901 if (log_martians &&
902 peer->rate_tokens == ip_rt_redirect_number)
903 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
904 &ip_hdr(skb)->saddr, inet_iif(skb),
905 &ip_hdr(skb)->daddr, &gw);
906 #endif
907 }
908 out_put_peer:
909 inet_putpeer(peer);
910 }
911
912 static int ip_error(struct sk_buff *skb)
913 {
914 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
915 struct rtable *rt = skb_rtable(skb);
916 struct inet_peer *peer;
917 unsigned long now;
918 struct net *net;
919 bool send;
920 int code;
921
922 /* IP on this device is disabled. */
923 if (!in_dev)
924 goto out;
925
926 net = dev_net(rt->dst.dev);
927 if (!IN_DEV_FORWARD(in_dev)) {
928 switch (rt->dst.error) {
929 case EHOSTUNREACH:
930 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
931 break;
932
933 case ENETUNREACH:
934 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
935 break;
936 }
937 goto out;
938 }
939
940 switch (rt->dst.error) {
941 case EINVAL:
942 default:
943 goto out;
944 case EHOSTUNREACH:
945 code = ICMP_HOST_UNREACH;
946 break;
947 case ENETUNREACH:
948 code = ICMP_NET_UNREACH;
949 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
950 break;
951 case EACCES:
952 code = ICMP_PKT_FILTERED;
953 break;
954 }
955
956 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
957 l3mdev_master_ifindex(skb->dev), 1);
958
959 send = true;
960 if (peer) {
961 now = jiffies;
962 peer->rate_tokens += now - peer->rate_last;
963 if (peer->rate_tokens > ip_rt_error_burst)
964 peer->rate_tokens = ip_rt_error_burst;
965 peer->rate_last = now;
966 if (peer->rate_tokens >= ip_rt_error_cost)
967 peer->rate_tokens -= ip_rt_error_cost;
968 else
969 send = false;
970 inet_putpeer(peer);
971 }
972 if (send)
973 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
974
975 out: kfree_skb(skb);
976 return 0;
977 }
978
979 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
980 {
981 struct dst_entry *dst = &rt->dst;
982 struct fib_result res;
983
984 if (dst_metric_locked(dst, RTAX_MTU))
985 return;
986
987 if (ipv4_mtu(dst) < mtu)
988 return;
989
990 if (mtu < ip_rt_min_pmtu)
991 mtu = ip_rt_min_pmtu;
992
993 if (rt->rt_pmtu == mtu &&
994 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
995 return;
996
997 rcu_read_lock();
998 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
999 struct fib_nh *nh = &FIB_RES_NH(res);
1000
1001 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
1002 jiffies + ip_rt_mtu_expires);
1003 }
1004 rcu_read_unlock();
1005 }
1006
1007 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1008 struct sk_buff *skb, u32 mtu)
1009 {
1010 struct rtable *rt = (struct rtable *) dst;
1011 struct flowi4 fl4;
1012
1013 ip_rt_build_flow_key(&fl4, sk, skb);
1014 __ip_rt_update_pmtu(rt, &fl4, mtu);
1015 }
1016
1017 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1018 int oif, u32 mark, u8 protocol, int flow_flags)
1019 {
1020 const struct iphdr *iph = (const struct iphdr *) skb->data;
1021 struct flowi4 fl4;
1022 struct rtable *rt;
1023
1024 if (!mark)
1025 mark = IP4_REPLY_MARK(net, skb->mark);
1026
1027 __build_flow_key(net, &fl4, NULL, iph, oif,
1028 RT_TOS(iph->tos), protocol, mark, flow_flags);
1029 rt = __ip_route_output_key(net, &fl4);
1030 if (!IS_ERR(rt)) {
1031 __ip_rt_update_pmtu(rt, &fl4, mtu);
1032 ip_rt_put(rt);
1033 }
1034 }
1035 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1036
1037 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1038 {
1039 const struct iphdr *iph = (const struct iphdr *) skb->data;
1040 struct flowi4 fl4;
1041 struct rtable *rt;
1042
1043 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1044
1045 if (!fl4.flowi4_mark)
1046 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1047
1048 rt = __ip_route_output_key(sock_net(sk), &fl4);
1049 if (!IS_ERR(rt)) {
1050 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 ip_rt_put(rt);
1052 }
1053 }
1054
1055 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1056 {
1057 const struct iphdr *iph = (const struct iphdr *) skb->data;
1058 struct flowi4 fl4;
1059 struct rtable *rt;
1060 struct dst_entry *odst = NULL;
1061 bool new = false;
1062 struct net *net = sock_net(sk);
1063
1064 bh_lock_sock(sk);
1065
1066 if (!ip_sk_accept_pmtu(sk))
1067 goto out;
1068
1069 odst = sk_dst_get(sk);
1070
1071 if (sock_owned_by_user(sk) || !odst) {
1072 __ipv4_sk_update_pmtu(skb, sk, mtu);
1073 goto out;
1074 }
1075
1076 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1077
1078 rt = (struct rtable *)odst;
1079 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1080 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1081 if (IS_ERR(rt))
1082 goto out;
1083
1084 new = true;
1085 }
1086
1087 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1088
1089 if (!dst_check(&rt->dst, 0)) {
1090 if (new)
1091 dst_release(&rt->dst);
1092
1093 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1094 if (IS_ERR(rt))
1095 goto out;
1096
1097 new = true;
1098 }
1099
1100 if (new)
1101 sk_dst_set(sk, &rt->dst);
1102
1103 out:
1104 bh_unlock_sock(sk);
1105 dst_release(odst);
1106 }
1107 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1108
1109 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1110 int oif, u32 mark, u8 protocol, int flow_flags)
1111 {
1112 const struct iphdr *iph = (const struct iphdr *) skb->data;
1113 struct flowi4 fl4;
1114 struct rtable *rt;
1115
1116 __build_flow_key(net, &fl4, NULL, iph, oif,
1117 RT_TOS(iph->tos), protocol, mark, flow_flags);
1118 rt = __ip_route_output_key(net, &fl4);
1119 if (!IS_ERR(rt)) {
1120 __ip_do_redirect(rt, skb, &fl4, false);
1121 ip_rt_put(rt);
1122 }
1123 }
1124 EXPORT_SYMBOL_GPL(ipv4_redirect);
1125
1126 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1127 {
1128 const struct iphdr *iph = (const struct iphdr *) skb->data;
1129 struct flowi4 fl4;
1130 struct rtable *rt;
1131 struct net *net = sock_net(sk);
1132
1133 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1134 rt = __ip_route_output_key(net, &fl4);
1135 if (!IS_ERR(rt)) {
1136 __ip_do_redirect(rt, skb, &fl4, false);
1137 ip_rt_put(rt);
1138 }
1139 }
1140 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1141
1142 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1143 {
1144 struct rtable *rt = (struct rtable *) dst;
1145
1146 /* All IPV4 dsts are created with ->obsolete set to the value
1147 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1148 * into this function always.
1149 *
1150 * When a PMTU/redirect information update invalidates a route,
1151 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1152 * DST_OBSOLETE_DEAD by dst_free().
1153 */
1154 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1155 return NULL;
1156 return dst;
1157 }
1158
1159 static void ipv4_link_failure(struct sk_buff *skb)
1160 {
1161 struct rtable *rt;
1162
1163 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1164
1165 rt = skb_rtable(skb);
1166 if (rt)
1167 dst_set_expires(&rt->dst, 0);
1168 }
1169
1170 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1171 {
1172 pr_debug("%s: %pI4 -> %pI4, %s\n",
1173 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1174 skb->dev ? skb->dev->name : "?");
1175 kfree_skb(skb);
1176 WARN_ON(1);
1177 return 0;
1178 }
1179
1180 /*
1181 We do not cache source address of outgoing interface,
1182 because it is used only by IP RR, TS and SRR options,
1183 so that it out of fast path.
1184
1185 BTW remember: "addr" is allowed to be not aligned
1186 in IP options!
1187 */
1188
1189 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1190 {
1191 __be32 src;
1192
1193 if (rt_is_output_route(rt))
1194 src = ip_hdr(skb)->saddr;
1195 else {
1196 struct fib_result res;
1197 struct flowi4 fl4;
1198 struct iphdr *iph;
1199
1200 iph = ip_hdr(skb);
1201
1202 memset(&fl4, 0, sizeof(fl4));
1203 fl4.daddr = iph->daddr;
1204 fl4.saddr = iph->saddr;
1205 fl4.flowi4_tos = RT_TOS(iph->tos);
1206 fl4.flowi4_oif = rt->dst.dev->ifindex;
1207 fl4.flowi4_iif = skb->dev->ifindex;
1208 fl4.flowi4_mark = skb->mark;
1209
1210 rcu_read_lock();
1211 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1212 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1213 else
1214 src = inet_select_addr(rt->dst.dev,
1215 rt_nexthop(rt, iph->daddr),
1216 RT_SCOPE_UNIVERSE);
1217 rcu_read_unlock();
1218 }
1219 memcpy(addr, &src, 4);
1220 }
1221
1222 #ifdef CONFIG_IP_ROUTE_CLASSID
1223 static void set_class_tag(struct rtable *rt, u32 tag)
1224 {
1225 if (!(rt->dst.tclassid & 0xFFFF))
1226 rt->dst.tclassid |= tag & 0xFFFF;
1227 if (!(rt->dst.tclassid & 0xFFFF0000))
1228 rt->dst.tclassid |= tag & 0xFFFF0000;
1229 }
1230 #endif
1231
1232 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1233 {
1234 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1235
1236 if (advmss == 0) {
1237 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1238 ip_rt_min_advmss);
1239 if (advmss > 65535 - 40)
1240 advmss = 65535 - 40;
1241 }
1242 return advmss;
1243 }
1244
1245 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1246 {
1247 const struct rtable *rt = (const struct rtable *) dst;
1248 unsigned int mtu = rt->rt_pmtu;
1249
1250 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1251 mtu = dst_metric_raw(dst, RTAX_MTU);
1252
1253 if (mtu)
1254 return mtu;
1255
1256 mtu = dst->dev->mtu;
1257
1258 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1259 if (rt->rt_uses_gateway && mtu > 576)
1260 mtu = 576;
1261 }
1262
1263 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1264
1265 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1266 }
1267
1268 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1269 {
1270 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1271 struct fib_nh_exception *fnhe;
1272 u32 hval;
1273
1274 if (!hash)
1275 return NULL;
1276
1277 hval = fnhe_hashfun(daddr);
1278
1279 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1280 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1281 if (fnhe->fnhe_daddr == daddr)
1282 return fnhe;
1283 }
1284 return NULL;
1285 }
1286
1287 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1288 __be32 daddr)
1289 {
1290 bool ret = false;
1291
1292 spin_lock_bh(&fnhe_lock);
1293
1294 if (daddr == fnhe->fnhe_daddr) {
1295 struct rtable __rcu **porig;
1296 struct rtable *orig;
1297 int genid = fnhe_genid(dev_net(rt->dst.dev));
1298
1299 if (rt_is_input_route(rt))
1300 porig = &fnhe->fnhe_rth_input;
1301 else
1302 porig = &fnhe->fnhe_rth_output;
1303 orig = rcu_dereference(*porig);
1304
1305 if (fnhe->fnhe_genid != genid) {
1306 fnhe->fnhe_genid = genid;
1307 fnhe->fnhe_gw = 0;
1308 fnhe->fnhe_pmtu = 0;
1309 fnhe->fnhe_expires = 0;
1310 fnhe_flush_routes(fnhe);
1311 orig = NULL;
1312 }
1313 fill_route_from_fnhe(rt, fnhe);
1314 if (!rt->rt_gateway)
1315 rt->rt_gateway = daddr;
1316
1317 if (!(rt->dst.flags & DST_NOCACHE)) {
1318 rcu_assign_pointer(*porig, rt);
1319 if (orig)
1320 rt_free(orig);
1321 ret = true;
1322 }
1323
1324 fnhe->fnhe_stamp = jiffies;
1325 }
1326 spin_unlock_bh(&fnhe_lock);
1327
1328 return ret;
1329 }
1330
1331 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1332 {
1333 struct rtable *orig, *prev, **p;
1334 bool ret = true;
1335
1336 if (rt_is_input_route(rt)) {
1337 p = (struct rtable **)&nh->nh_rth_input;
1338 } else {
1339 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1340 }
1341 orig = *p;
1342
1343 prev = cmpxchg(p, orig, rt);
1344 if (prev == orig) {
1345 if (orig)
1346 rt_free(orig);
1347 } else
1348 ret = false;
1349
1350 return ret;
1351 }
1352
1353 struct uncached_list {
1354 spinlock_t lock;
1355 struct list_head head;
1356 };
1357
1358 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1359
1360 static void rt_add_uncached_list(struct rtable *rt)
1361 {
1362 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1363
1364 rt->rt_uncached_list = ul;
1365
1366 spin_lock_bh(&ul->lock);
1367 list_add_tail(&rt->rt_uncached, &ul->head);
1368 spin_unlock_bh(&ul->lock);
1369 }
1370
1371 static void ipv4_dst_destroy(struct dst_entry *dst)
1372 {
1373 struct rtable *rt = (struct rtable *) dst;
1374
1375 if (!list_empty(&rt->rt_uncached)) {
1376 struct uncached_list *ul = rt->rt_uncached_list;
1377
1378 spin_lock_bh(&ul->lock);
1379 list_del(&rt->rt_uncached);
1380 spin_unlock_bh(&ul->lock);
1381 }
1382 }
1383
1384 void rt_flush_dev(struct net_device *dev)
1385 {
1386 struct net *net = dev_net(dev);
1387 struct rtable *rt;
1388 int cpu;
1389
1390 for_each_possible_cpu(cpu) {
1391 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1392
1393 spin_lock_bh(&ul->lock);
1394 list_for_each_entry(rt, &ul->head, rt_uncached) {
1395 if (rt->dst.dev != dev)
1396 continue;
1397 rt->dst.dev = net->loopback_dev;
1398 dev_hold(rt->dst.dev);
1399 dev_put(dev);
1400 }
1401 spin_unlock_bh(&ul->lock);
1402 }
1403 }
1404
1405 static bool rt_cache_valid(const struct rtable *rt)
1406 {
1407 return rt &&
1408 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1409 !rt_is_expired(rt);
1410 }
1411
1412 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1413 const struct fib_result *res,
1414 struct fib_nh_exception *fnhe,
1415 struct fib_info *fi, u16 type, u32 itag)
1416 {
1417 bool cached = false;
1418
1419 if (fi) {
1420 struct fib_nh *nh = &FIB_RES_NH(*res);
1421
1422 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1423 rt->rt_gateway = nh->nh_gw;
1424 rt->rt_uses_gateway = 1;
1425 }
1426 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1427 #ifdef CONFIG_IP_ROUTE_CLASSID
1428 rt->dst.tclassid = nh->nh_tclassid;
1429 #endif
1430 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1431 if (unlikely(fnhe))
1432 cached = rt_bind_exception(rt, fnhe, daddr);
1433 else if (!(rt->dst.flags & DST_NOCACHE))
1434 cached = rt_cache_route(nh, rt);
1435 if (unlikely(!cached)) {
1436 /* Routes we intend to cache in nexthop exception or
1437 * FIB nexthop have the DST_NOCACHE bit clear.
1438 * However, if we are unsuccessful at storing this
1439 * route into the cache we really need to set it.
1440 */
1441 rt->dst.flags |= DST_NOCACHE;
1442 if (!rt->rt_gateway)
1443 rt->rt_gateway = daddr;
1444 rt_add_uncached_list(rt);
1445 }
1446 } else
1447 rt_add_uncached_list(rt);
1448
1449 #ifdef CONFIG_IP_ROUTE_CLASSID
1450 #ifdef CONFIG_IP_MULTIPLE_TABLES
1451 set_class_tag(rt, res->tclassid);
1452 #endif
1453 set_class_tag(rt, itag);
1454 #endif
1455 }
1456
1457 struct rtable *rt_dst_alloc(struct net_device *dev,
1458 unsigned int flags, u16 type,
1459 bool nopolicy, bool noxfrm, bool will_cache)
1460 {
1461 struct rtable *rt;
1462
1463 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1464 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1465 (nopolicy ? DST_NOPOLICY : 0) |
1466 (noxfrm ? DST_NOXFRM : 0));
1467
1468 if (rt) {
1469 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1470 rt->rt_flags = flags;
1471 rt->rt_type = type;
1472 rt->rt_is_input = 0;
1473 rt->rt_iif = 0;
1474 rt->rt_pmtu = 0;
1475 rt->rt_gateway = 0;
1476 rt->rt_uses_gateway = 0;
1477 rt->rt_table_id = 0;
1478 INIT_LIST_HEAD(&rt->rt_uncached);
1479
1480 rt->dst.output = ip_output;
1481 if (flags & RTCF_LOCAL)
1482 rt->dst.input = ip_local_deliver;
1483 }
1484
1485 return rt;
1486 }
1487 EXPORT_SYMBOL(rt_dst_alloc);
1488
1489 /* called in rcu_read_lock() section */
1490 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1491 u8 tos, struct net_device *dev, int our)
1492 {
1493 struct rtable *rth;
1494 struct in_device *in_dev = __in_dev_get_rcu(dev);
1495 unsigned int flags = RTCF_MULTICAST;
1496 u32 itag = 0;
1497 int err;
1498
1499 /* Primary sanity checks. */
1500
1501 if (!in_dev)
1502 return -EINVAL;
1503
1504 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1505 skb->protocol != htons(ETH_P_IP))
1506 goto e_inval;
1507
1508 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1509 goto e_inval;
1510
1511 if (ipv4_is_zeronet(saddr)) {
1512 if (!ipv4_is_local_multicast(daddr))
1513 goto e_inval;
1514 } else {
1515 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1516 in_dev, &itag);
1517 if (err < 0)
1518 goto e_err;
1519 }
1520 if (our)
1521 flags |= RTCF_LOCAL;
1522
1523 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1524 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1525 if (!rth)
1526 goto e_nobufs;
1527
1528 #ifdef CONFIG_IP_ROUTE_CLASSID
1529 rth->dst.tclassid = itag;
1530 #endif
1531 rth->dst.output = ip_rt_bug;
1532 rth->rt_is_input= 1;
1533
1534 #ifdef CONFIG_IP_MROUTE
1535 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1536 rth->dst.input = ip_mr_input;
1537 #endif
1538 RT_CACHE_STAT_INC(in_slow_mc);
1539
1540 skb_dst_set(skb, &rth->dst);
1541 return 0;
1542
1543 e_nobufs:
1544 return -ENOBUFS;
1545 e_inval:
1546 return -EINVAL;
1547 e_err:
1548 return err;
1549 }
1550
1551
1552 static void ip_handle_martian_source(struct net_device *dev,
1553 struct in_device *in_dev,
1554 struct sk_buff *skb,
1555 __be32 daddr,
1556 __be32 saddr)
1557 {
1558 RT_CACHE_STAT_INC(in_martian_src);
1559 #ifdef CONFIG_IP_ROUTE_VERBOSE
1560 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1561 /*
1562 * RFC1812 recommendation, if source is martian,
1563 * the only hint is MAC header.
1564 */
1565 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1566 &daddr, &saddr, dev->name);
1567 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1568 print_hex_dump(KERN_WARNING, "ll header: ",
1569 DUMP_PREFIX_OFFSET, 16, 1,
1570 skb_mac_header(skb),
1571 dev->hard_header_len, true);
1572 }
1573 }
1574 #endif
1575 }
1576
1577 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1578 {
1579 struct fnhe_hash_bucket *hash;
1580 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1581 u32 hval = fnhe_hashfun(daddr);
1582
1583 spin_lock_bh(&fnhe_lock);
1584
1585 hash = rcu_dereference_protected(nh->nh_exceptions,
1586 lockdep_is_held(&fnhe_lock));
1587 hash += hval;
1588
1589 fnhe_p = &hash->chain;
1590 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1591 while (fnhe) {
1592 if (fnhe->fnhe_daddr == daddr) {
1593 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1594 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1595 fnhe_flush_routes(fnhe);
1596 kfree_rcu(fnhe, rcu);
1597 break;
1598 }
1599 fnhe_p = &fnhe->fnhe_next;
1600 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1601 lockdep_is_held(&fnhe_lock));
1602 }
1603
1604 spin_unlock_bh(&fnhe_lock);
1605 }
1606
1607 static void set_lwt_redirect(struct rtable *rth)
1608 {
1609 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1610 rth->dst.lwtstate->orig_output = rth->dst.output;
1611 rth->dst.output = lwtunnel_output;
1612 }
1613
1614 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1615 rth->dst.lwtstate->orig_input = rth->dst.input;
1616 rth->dst.input = lwtunnel_input;
1617 }
1618 }
1619
1620 /* called in rcu_read_lock() section */
1621 static int __mkroute_input(struct sk_buff *skb,
1622 const struct fib_result *res,
1623 struct in_device *in_dev,
1624 __be32 daddr, __be32 saddr, u32 tos)
1625 {
1626 struct fib_nh_exception *fnhe;
1627 struct rtable *rth;
1628 int err;
1629 struct in_device *out_dev;
1630 bool do_cache;
1631 u32 itag = 0;
1632
1633 /* get a working reference to the output device */
1634 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1635 if (!out_dev) {
1636 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1637 return -EINVAL;
1638 }
1639
1640 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1641 in_dev->dev, in_dev, &itag);
1642 if (err < 0) {
1643 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1644 saddr);
1645
1646 goto cleanup;
1647 }
1648
1649 do_cache = res->fi && !itag;
1650 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1651 skb->protocol == htons(ETH_P_IP) &&
1652 (IN_DEV_SHARED_MEDIA(out_dev) ||
1653 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1654 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1655
1656 if (skb->protocol != htons(ETH_P_IP)) {
1657 /* Not IP (i.e. ARP). Do not create route, if it is
1658 * invalid for proxy arp. DNAT routes are always valid.
1659 *
1660 * Proxy arp feature have been extended to allow, ARP
1661 * replies back to the same interface, to support
1662 * Private VLAN switch technologies. See arp.c.
1663 */
1664 if (out_dev == in_dev &&
1665 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1666 err = -EINVAL;
1667 goto cleanup;
1668 }
1669 }
1670
1671 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1672 if (do_cache) {
1673 if (fnhe) {
1674 rth = rcu_dereference(fnhe->fnhe_rth_input);
1675 if (rth && rth->dst.expires &&
1676 time_after(jiffies, rth->dst.expires)) {
1677 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1678 fnhe = NULL;
1679 } else {
1680 goto rt_cache;
1681 }
1682 }
1683
1684 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1685
1686 rt_cache:
1687 if (rt_cache_valid(rth)) {
1688 skb_dst_set_noref(skb, &rth->dst);
1689 goto out;
1690 }
1691 }
1692
1693 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1694 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1695 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1696 if (!rth) {
1697 err = -ENOBUFS;
1698 goto cleanup;
1699 }
1700
1701 rth->rt_is_input = 1;
1702 if (res->table)
1703 rth->rt_table_id = res->table->tb_id;
1704 RT_CACHE_STAT_INC(in_slow_tot);
1705
1706 rth->dst.input = ip_forward;
1707
1708 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1709 set_lwt_redirect(rth);
1710 skb_dst_set(skb, &rth->dst);
1711 out:
1712 err = 0;
1713 cleanup:
1714 return err;
1715 }
1716
1717 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1718
1719 /* To make ICMP packets follow the right flow, the multipath hash is
1720 * calculated from the inner IP addresses in reverse order.
1721 */
1722 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1723 {
1724 const struct iphdr *outer_iph = ip_hdr(skb);
1725 struct icmphdr _icmph;
1726 const struct icmphdr *icmph;
1727 struct iphdr _inner_iph;
1728 const struct iphdr *inner_iph;
1729
1730 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1731 goto standard_hash;
1732
1733 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1734 &_icmph);
1735 if (!icmph)
1736 goto standard_hash;
1737
1738 if (icmph->type != ICMP_DEST_UNREACH &&
1739 icmph->type != ICMP_REDIRECT &&
1740 icmph->type != ICMP_TIME_EXCEEDED &&
1741 icmph->type != ICMP_PARAMETERPROB) {
1742 goto standard_hash;
1743 }
1744
1745 inner_iph = skb_header_pointer(skb,
1746 outer_iph->ihl * 4 + sizeof(_icmph),
1747 sizeof(_inner_iph), &_inner_iph);
1748 if (!inner_iph)
1749 goto standard_hash;
1750
1751 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1752
1753 standard_hash:
1754 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1755 }
1756
1757 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1758
1759 static int ip_mkroute_input(struct sk_buff *skb,
1760 struct fib_result *res,
1761 const struct flowi4 *fl4,
1762 struct in_device *in_dev,
1763 __be32 daddr, __be32 saddr, u32 tos)
1764 {
1765 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1766 if (res->fi && res->fi->fib_nhs > 1) {
1767 int h;
1768
1769 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1770 h = ip_multipath_icmp_hash(skb);
1771 else
1772 h = fib_multipath_hash(saddr, daddr);
1773 fib_select_multipath(res, h);
1774 }
1775 #endif
1776
1777 /* create a routing cache entry */
1778 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1779 }
1780
1781 /*
1782 * NOTE. We drop all the packets that has local source
1783 * addresses, because every properly looped back packet
1784 * must have correct destination already attached by output routine.
1785 *
1786 * Such approach solves two big problems:
1787 * 1. Not simplex devices are handled properly.
1788 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1789 * called with rcu_read_lock()
1790 */
1791
1792 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1793 u8 tos, struct net_device *dev)
1794 {
1795 struct fib_result res;
1796 struct in_device *in_dev = __in_dev_get_rcu(dev);
1797 struct ip_tunnel_info *tun_info;
1798 struct flowi4 fl4;
1799 unsigned int flags = 0;
1800 u32 itag = 0;
1801 struct rtable *rth;
1802 int err = -EINVAL;
1803 struct net *net = dev_net(dev);
1804 bool do_cache;
1805
1806 /* IP on this device is disabled. */
1807
1808 if (!in_dev)
1809 goto out;
1810
1811 /* Check for the most weird martians, which can be not detected
1812 by fib_lookup.
1813 */
1814
1815 tun_info = skb_tunnel_info(skb);
1816 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1817 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1818 else
1819 fl4.flowi4_tun_key.tun_id = 0;
1820 skb_dst_drop(skb);
1821
1822 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1823 goto martian_source;
1824
1825 res.fi = NULL;
1826 res.table = NULL;
1827 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1828 goto brd_input;
1829
1830 /* Accept zero addresses only to limited broadcast;
1831 * I even do not know to fix it or not. Waiting for complains :-)
1832 */
1833 if (ipv4_is_zeronet(saddr))
1834 goto martian_source;
1835
1836 if (ipv4_is_zeronet(daddr))
1837 goto martian_destination;
1838
1839 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1840 * and call it once if daddr or/and saddr are loopback addresses
1841 */
1842 if (ipv4_is_loopback(daddr)) {
1843 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1844 goto martian_destination;
1845 } else if (ipv4_is_loopback(saddr)) {
1846 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1847 goto martian_source;
1848 }
1849
1850 /*
1851 * Now we are ready to route packet.
1852 */
1853 fl4.flowi4_oif = 0;
1854 fl4.flowi4_iif = dev->ifindex;
1855 fl4.flowi4_mark = skb->mark;
1856 fl4.flowi4_tos = tos;
1857 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1858 fl4.flowi4_flags = 0;
1859 fl4.daddr = daddr;
1860 fl4.saddr = saddr;
1861 err = fib_lookup(net, &fl4, &res, 0);
1862 if (err != 0) {
1863 if (!IN_DEV_FORWARD(in_dev))
1864 err = -EHOSTUNREACH;
1865 goto no_route;
1866 }
1867
1868 if (res.type == RTN_BROADCAST)
1869 goto brd_input;
1870
1871 if (res.type == RTN_LOCAL) {
1872 err = fib_validate_source(skb, saddr, daddr, tos,
1873 0, dev, in_dev, &itag);
1874 if (err < 0)
1875 goto martian_source;
1876 goto local_input;
1877 }
1878
1879 if (!IN_DEV_FORWARD(in_dev)) {
1880 err = -EHOSTUNREACH;
1881 goto no_route;
1882 }
1883 if (res.type != RTN_UNICAST)
1884 goto martian_destination;
1885
1886 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1887 out: return err;
1888
1889 brd_input:
1890 if (skb->protocol != htons(ETH_P_IP))
1891 goto e_inval;
1892
1893 if (!ipv4_is_zeronet(saddr)) {
1894 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1895 in_dev, &itag);
1896 if (err < 0)
1897 goto martian_source;
1898 }
1899 flags |= RTCF_BROADCAST;
1900 res.type = RTN_BROADCAST;
1901 RT_CACHE_STAT_INC(in_brd);
1902
1903 local_input:
1904 do_cache = false;
1905 if (res.fi) {
1906 if (!itag) {
1907 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1908 if (rt_cache_valid(rth)) {
1909 skb_dst_set_noref(skb, &rth->dst);
1910 err = 0;
1911 goto out;
1912 }
1913 do_cache = true;
1914 }
1915 }
1916
1917 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
1918 flags | RTCF_LOCAL, res.type,
1919 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1920 if (!rth)
1921 goto e_nobufs;
1922
1923 rth->dst.output= ip_rt_bug;
1924 #ifdef CONFIG_IP_ROUTE_CLASSID
1925 rth->dst.tclassid = itag;
1926 #endif
1927 rth->rt_is_input = 1;
1928 if (res.table)
1929 rth->rt_table_id = res.table->tb_id;
1930
1931 RT_CACHE_STAT_INC(in_slow_tot);
1932 if (res.type == RTN_UNREACHABLE) {
1933 rth->dst.input= ip_error;
1934 rth->dst.error= -err;
1935 rth->rt_flags &= ~RTCF_LOCAL;
1936 }
1937
1938 if (do_cache) {
1939 struct fib_nh *nh = &FIB_RES_NH(res);
1940
1941 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1942 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1943 WARN_ON(rth->dst.input == lwtunnel_input);
1944 rth->dst.lwtstate->orig_input = rth->dst.input;
1945 rth->dst.input = lwtunnel_input;
1946 }
1947
1948 if (unlikely(!rt_cache_route(nh, rth))) {
1949 rth->dst.flags |= DST_NOCACHE;
1950 rt_add_uncached_list(rth);
1951 }
1952 }
1953 skb_dst_set(skb, &rth->dst);
1954 err = 0;
1955 goto out;
1956
1957 no_route:
1958 RT_CACHE_STAT_INC(in_no_route);
1959 res.type = RTN_UNREACHABLE;
1960 res.fi = NULL;
1961 res.table = NULL;
1962 goto local_input;
1963
1964 /*
1965 * Do not cache martian addresses: they should be logged (RFC1812)
1966 */
1967 martian_destination:
1968 RT_CACHE_STAT_INC(in_martian_dst);
1969 #ifdef CONFIG_IP_ROUTE_VERBOSE
1970 if (IN_DEV_LOG_MARTIANS(in_dev))
1971 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1972 &daddr, &saddr, dev->name);
1973 #endif
1974
1975 e_inval:
1976 err = -EINVAL;
1977 goto out;
1978
1979 e_nobufs:
1980 err = -ENOBUFS;
1981 goto out;
1982
1983 martian_source:
1984 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1985 goto out;
1986 }
1987
1988 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1989 u8 tos, struct net_device *dev)
1990 {
1991 int res;
1992
1993 rcu_read_lock();
1994
1995 /* Multicast recognition logic is moved from route cache to here.
1996 The problem was that too many Ethernet cards have broken/missing
1997 hardware multicast filters :-( As result the host on multicasting
1998 network acquires a lot of useless route cache entries, sort of
1999 SDR messages from all the world. Now we try to get rid of them.
2000 Really, provided software IP multicast filter is organized
2001 reasonably (at least, hashed), it does not result in a slowdown
2002 comparing with route cache reject entries.
2003 Note, that multicast routers are not affected, because
2004 route cache entry is created eventually.
2005 */
2006 if (ipv4_is_multicast(daddr)) {
2007 struct in_device *in_dev = __in_dev_get_rcu(dev);
2008 int our = 0;
2009
2010 if (in_dev)
2011 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2012 ip_hdr(skb)->protocol);
2013
2014 /* check l3 master if no match yet */
2015 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2016 struct in_device *l3_in_dev;
2017
2018 l3_in_dev = __in_dev_get_rcu(skb->dev);
2019 if (l3_in_dev)
2020 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2021 ip_hdr(skb)->protocol);
2022 }
2023
2024 res = -EINVAL;
2025 if (our
2026 #ifdef CONFIG_IP_MROUTE
2027 ||
2028 (!ipv4_is_local_multicast(daddr) &&
2029 IN_DEV_MFORWARD(in_dev))
2030 #endif
2031 ) {
2032 res = ip_route_input_mc(skb, daddr, saddr,
2033 tos, dev, our);
2034 }
2035 rcu_read_unlock();
2036 return res;
2037 }
2038 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2039 rcu_read_unlock();
2040 return res;
2041 }
2042 EXPORT_SYMBOL(ip_route_input_noref);
2043
2044 /* called with rcu_read_lock() */
2045 static struct rtable *__mkroute_output(const struct fib_result *res,
2046 const struct flowi4 *fl4, int orig_oif,
2047 struct net_device *dev_out,
2048 unsigned int flags)
2049 {
2050 struct fib_info *fi = res->fi;
2051 struct fib_nh_exception *fnhe;
2052 struct in_device *in_dev;
2053 u16 type = res->type;
2054 struct rtable *rth;
2055 bool do_cache;
2056
2057 in_dev = __in_dev_get_rcu(dev_out);
2058 if (!in_dev)
2059 return ERR_PTR(-EINVAL);
2060
2061 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2062 if (ipv4_is_loopback(fl4->saddr) &&
2063 !(dev_out->flags & IFF_LOOPBACK) &&
2064 !netif_is_l3_master(dev_out))
2065 return ERR_PTR(-EINVAL);
2066
2067 if (ipv4_is_lbcast(fl4->daddr))
2068 type = RTN_BROADCAST;
2069 else if (ipv4_is_multicast(fl4->daddr))
2070 type = RTN_MULTICAST;
2071 else if (ipv4_is_zeronet(fl4->daddr))
2072 return ERR_PTR(-EINVAL);
2073
2074 if (dev_out->flags & IFF_LOOPBACK)
2075 flags |= RTCF_LOCAL;
2076
2077 do_cache = true;
2078 if (type == RTN_BROADCAST) {
2079 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2080 fi = NULL;
2081 } else if (type == RTN_MULTICAST) {
2082 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2083 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2084 fl4->flowi4_proto))
2085 flags &= ~RTCF_LOCAL;
2086 else
2087 do_cache = false;
2088 /* If multicast route do not exist use
2089 * default one, but do not gateway in this case.
2090 * Yes, it is hack.
2091 */
2092 if (fi && res->prefixlen < 4)
2093 fi = NULL;
2094 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2095 (orig_oif != dev_out->ifindex)) {
2096 /* For local routes that require a particular output interface
2097 * we do not want to cache the result. Caching the result
2098 * causes incorrect behaviour when there are multiple source
2099 * addresses on the interface, the end result being that if the
2100 * intended recipient is waiting on that interface for the
2101 * packet he won't receive it because it will be delivered on
2102 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2103 * be set to the loopback interface as well.
2104 */
2105 fi = NULL;
2106 }
2107
2108 fnhe = NULL;
2109 do_cache &= fi != NULL;
2110 if (do_cache) {
2111 struct rtable __rcu **prth;
2112 struct fib_nh *nh = &FIB_RES_NH(*res);
2113
2114 fnhe = find_exception(nh, fl4->daddr);
2115 if (fnhe) {
2116 prth = &fnhe->fnhe_rth_output;
2117 rth = rcu_dereference(*prth);
2118 if (rth && rth->dst.expires &&
2119 time_after(jiffies, rth->dst.expires)) {
2120 ip_del_fnhe(nh, fl4->daddr);
2121 fnhe = NULL;
2122 } else {
2123 goto rt_cache;
2124 }
2125 }
2126
2127 if (unlikely(fl4->flowi4_flags &
2128 FLOWI_FLAG_KNOWN_NH &&
2129 !(nh->nh_gw &&
2130 nh->nh_scope == RT_SCOPE_LINK))) {
2131 do_cache = false;
2132 goto add;
2133 }
2134 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2135 rth = rcu_dereference(*prth);
2136
2137 rt_cache:
2138 if (rt_cache_valid(rth)) {
2139 dst_hold(&rth->dst);
2140 return rth;
2141 }
2142 }
2143
2144 add:
2145 rth = rt_dst_alloc(dev_out, flags, type,
2146 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2147 IN_DEV_CONF_GET(in_dev, NOXFRM),
2148 do_cache);
2149 if (!rth)
2150 return ERR_PTR(-ENOBUFS);
2151
2152 rth->rt_iif = orig_oif ? : 0;
2153 if (res->table)
2154 rth->rt_table_id = res->table->tb_id;
2155
2156 RT_CACHE_STAT_INC(out_slow_tot);
2157
2158 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2159 if (flags & RTCF_LOCAL &&
2160 !(dev_out->flags & IFF_LOOPBACK)) {
2161 rth->dst.output = ip_mc_output;
2162 RT_CACHE_STAT_INC(out_slow_mc);
2163 }
2164 #ifdef CONFIG_IP_MROUTE
2165 if (type == RTN_MULTICAST) {
2166 if (IN_DEV_MFORWARD(in_dev) &&
2167 !ipv4_is_local_multicast(fl4->daddr)) {
2168 rth->dst.input = ip_mr_input;
2169 rth->dst.output = ip_mc_output;
2170 }
2171 }
2172 #endif
2173 }
2174
2175 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2176 set_lwt_redirect(rth);
2177
2178 return rth;
2179 }
2180
2181 /*
2182 * Major route resolver routine.
2183 */
2184
2185 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2186 int mp_hash)
2187 {
2188 struct net_device *dev_out = NULL;
2189 __u8 tos = RT_FL_TOS(fl4);
2190 unsigned int flags = 0;
2191 struct fib_result res;
2192 struct rtable *rth;
2193 int orig_oif;
2194 int err = -ENETUNREACH;
2195
2196 res.tclassid = 0;
2197 res.fi = NULL;
2198 res.table = NULL;
2199
2200 orig_oif = fl4->flowi4_oif;
2201
2202 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2203 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2204 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2205 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2206
2207 rcu_read_lock();
2208 if (fl4->saddr) {
2209 rth = ERR_PTR(-EINVAL);
2210 if (ipv4_is_multicast(fl4->saddr) ||
2211 ipv4_is_lbcast(fl4->saddr) ||
2212 ipv4_is_zeronet(fl4->saddr))
2213 goto out;
2214
2215 /* I removed check for oif == dev_out->oif here.
2216 It was wrong for two reasons:
2217 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2218 is assigned to multiple interfaces.
2219 2. Moreover, we are allowed to send packets with saddr
2220 of another iface. --ANK
2221 */
2222
2223 if (fl4->flowi4_oif == 0 &&
2224 (ipv4_is_multicast(fl4->daddr) ||
2225 ipv4_is_lbcast(fl4->daddr))) {
2226 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2227 dev_out = __ip_dev_find(net, fl4->saddr, false);
2228 if (!dev_out)
2229 goto out;
2230
2231 /* Special hack: user can direct multicasts
2232 and limited broadcast via necessary interface
2233 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2234 This hack is not just for fun, it allows
2235 vic,vat and friends to work.
2236 They bind socket to loopback, set ttl to zero
2237 and expect that it will work.
2238 From the viewpoint of routing cache they are broken,
2239 because we are not allowed to build multicast path
2240 with loopback source addr (look, routing cache
2241 cannot know, that ttl is zero, so that packet
2242 will not leave this host and route is valid).
2243 Luckily, this hack is good workaround.
2244 */
2245
2246 fl4->flowi4_oif = dev_out->ifindex;
2247 goto make_route;
2248 }
2249
2250 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2251 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2252 if (!__ip_dev_find(net, fl4->saddr, false))
2253 goto out;
2254 }
2255 }
2256
2257
2258 if (fl4->flowi4_oif) {
2259 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2260 rth = ERR_PTR(-ENODEV);
2261 if (!dev_out)
2262 goto out;
2263
2264 /* RACE: Check return value of inet_select_addr instead. */
2265 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2266 rth = ERR_PTR(-ENETUNREACH);
2267 goto out;
2268 }
2269 if (ipv4_is_local_multicast(fl4->daddr) ||
2270 ipv4_is_lbcast(fl4->daddr) ||
2271 fl4->flowi4_proto == IPPROTO_IGMP) {
2272 if (!fl4->saddr)
2273 fl4->saddr = inet_select_addr(dev_out, 0,
2274 RT_SCOPE_LINK);
2275 goto make_route;
2276 }
2277 if (!fl4->saddr) {
2278 if (ipv4_is_multicast(fl4->daddr))
2279 fl4->saddr = inet_select_addr(dev_out, 0,
2280 fl4->flowi4_scope);
2281 else if (!fl4->daddr)
2282 fl4->saddr = inet_select_addr(dev_out, 0,
2283 RT_SCOPE_HOST);
2284 }
2285 }
2286
2287 if (!fl4->daddr) {
2288 fl4->daddr = fl4->saddr;
2289 if (!fl4->daddr)
2290 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2291 dev_out = net->loopback_dev;
2292 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2293 res.type = RTN_LOCAL;
2294 flags |= RTCF_LOCAL;
2295 goto make_route;
2296 }
2297
2298 err = fib_lookup(net, fl4, &res, 0);
2299 if (err) {
2300 res.fi = NULL;
2301 res.table = NULL;
2302 if (fl4->flowi4_oif &&
2303 (ipv4_is_multicast(fl4->daddr) ||
2304 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2305 /* Apparently, routing tables are wrong. Assume,
2306 that the destination is on link.
2307
2308 WHY? DW.
2309 Because we are allowed to send to iface
2310 even if it has NO routes and NO assigned
2311 addresses. When oif is specified, routing
2312 tables are looked up with only one purpose:
2313 to catch if destination is gatewayed, rather than
2314 direct. Moreover, if MSG_DONTROUTE is set,
2315 we send packet, ignoring both routing tables
2316 and ifaddr state. --ANK
2317
2318
2319 We could make it even if oif is unknown,
2320 likely IPv6, but we do not.
2321 */
2322
2323 if (fl4->saddr == 0)
2324 fl4->saddr = inet_select_addr(dev_out, 0,
2325 RT_SCOPE_LINK);
2326 res.type = RTN_UNICAST;
2327 goto make_route;
2328 }
2329 rth = ERR_PTR(err);
2330 goto out;
2331 }
2332
2333 if (res.type == RTN_LOCAL) {
2334 if (!fl4->saddr) {
2335 if (res.fi->fib_prefsrc)
2336 fl4->saddr = res.fi->fib_prefsrc;
2337 else
2338 fl4->saddr = fl4->daddr;
2339 }
2340
2341 /* L3 master device is the loopback for that domain */
2342 dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev;
2343 fl4->flowi4_oif = dev_out->ifindex;
2344 flags |= RTCF_LOCAL;
2345 goto make_route;
2346 }
2347
2348 fib_select_path(net, &res, fl4, mp_hash);
2349
2350 dev_out = FIB_RES_DEV(res);
2351 fl4->flowi4_oif = dev_out->ifindex;
2352
2353
2354 make_route:
2355 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2356
2357 out:
2358 rcu_read_unlock();
2359 return rth;
2360 }
2361 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2362
2363 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2364 {
2365 return NULL;
2366 }
2367
2368 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2369 {
2370 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2371
2372 return mtu ? : dst->dev->mtu;
2373 }
2374
2375 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2376 struct sk_buff *skb, u32 mtu)
2377 {
2378 }
2379
2380 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2381 struct sk_buff *skb)
2382 {
2383 }
2384
2385 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2386 unsigned long old)
2387 {
2388 return NULL;
2389 }
2390
2391 static struct dst_ops ipv4_dst_blackhole_ops = {
2392 .family = AF_INET,
2393 .check = ipv4_blackhole_dst_check,
2394 .mtu = ipv4_blackhole_mtu,
2395 .default_advmss = ipv4_default_advmss,
2396 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2397 .redirect = ipv4_rt_blackhole_redirect,
2398 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2399 .neigh_lookup = ipv4_neigh_lookup,
2400 };
2401
2402 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2403 {
2404 struct rtable *ort = (struct rtable *) dst_orig;
2405 struct rtable *rt;
2406
2407 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2408 if (rt) {
2409 struct dst_entry *new = &rt->dst;
2410
2411 new->__use = 1;
2412 new->input = dst_discard;
2413 new->output = dst_discard_out;
2414
2415 new->dev = ort->dst.dev;
2416 if (new->dev)
2417 dev_hold(new->dev);
2418
2419 rt->rt_is_input = ort->rt_is_input;
2420 rt->rt_iif = ort->rt_iif;
2421 rt->rt_pmtu = ort->rt_pmtu;
2422
2423 rt->rt_genid = rt_genid_ipv4(net);
2424 rt->rt_flags = ort->rt_flags;
2425 rt->rt_type = ort->rt_type;
2426 rt->rt_gateway = ort->rt_gateway;
2427 rt->rt_uses_gateway = ort->rt_uses_gateway;
2428
2429 INIT_LIST_HEAD(&rt->rt_uncached);
2430 dst_free(new);
2431 }
2432
2433 dst_release(dst_orig);
2434
2435 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2436 }
2437
2438 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2439 const struct sock *sk)
2440 {
2441 struct rtable *rt = __ip_route_output_key(net, flp4);
2442
2443 if (IS_ERR(rt))
2444 return rt;
2445
2446 if (flp4->flowi4_proto)
2447 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2448 flowi4_to_flowi(flp4),
2449 sk, 0);
2450
2451 return rt;
2452 }
2453 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2454
2455 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2456 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2457 u32 seq, int event, int nowait, unsigned int flags)
2458 {
2459 struct rtable *rt = skb_rtable(skb);
2460 struct rtmsg *r;
2461 struct nlmsghdr *nlh;
2462 unsigned long expires = 0;
2463 u32 error;
2464 u32 metrics[RTAX_MAX];
2465
2466 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2467 if (!nlh)
2468 return -EMSGSIZE;
2469
2470 r = nlmsg_data(nlh);
2471 r->rtm_family = AF_INET;
2472 r->rtm_dst_len = 32;
2473 r->rtm_src_len = 0;
2474 r->rtm_tos = fl4->flowi4_tos;
2475 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2476 if (nla_put_u32(skb, RTA_TABLE, table_id))
2477 goto nla_put_failure;
2478 r->rtm_type = rt->rt_type;
2479 r->rtm_scope = RT_SCOPE_UNIVERSE;
2480 r->rtm_protocol = RTPROT_UNSPEC;
2481 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2482 if (rt->rt_flags & RTCF_NOTIFY)
2483 r->rtm_flags |= RTM_F_NOTIFY;
2484 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2485 r->rtm_flags |= RTCF_DOREDIRECT;
2486
2487 if (nla_put_in_addr(skb, RTA_DST, dst))
2488 goto nla_put_failure;
2489 if (src) {
2490 r->rtm_src_len = 32;
2491 if (nla_put_in_addr(skb, RTA_SRC, src))
2492 goto nla_put_failure;
2493 }
2494 if (rt->dst.dev &&
2495 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2496 goto nla_put_failure;
2497 #ifdef CONFIG_IP_ROUTE_CLASSID
2498 if (rt->dst.tclassid &&
2499 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2500 goto nla_put_failure;
2501 #endif
2502 if (!rt_is_input_route(rt) &&
2503 fl4->saddr != src) {
2504 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2505 goto nla_put_failure;
2506 }
2507 if (rt->rt_uses_gateway &&
2508 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2509 goto nla_put_failure;
2510
2511 expires = rt->dst.expires;
2512 if (expires) {
2513 unsigned long now = jiffies;
2514
2515 if (time_before(now, expires))
2516 expires -= now;
2517 else
2518 expires = 0;
2519 }
2520
2521 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2522 if (rt->rt_pmtu && expires)
2523 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2524 if (rtnetlink_put_metrics(skb, metrics) < 0)
2525 goto nla_put_failure;
2526
2527 if (fl4->flowi4_mark &&
2528 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2529 goto nla_put_failure;
2530
2531 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2532 nla_put_u32(skb, RTA_UID,
2533 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2534 goto nla_put_failure;
2535
2536 error = rt->dst.error;
2537
2538 if (rt_is_input_route(rt)) {
2539 #ifdef CONFIG_IP_MROUTE
2540 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2541 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2542 int err = ipmr_get_route(net, skb,
2543 fl4->saddr, fl4->daddr,
2544 r, nowait, portid);
2545
2546 if (err <= 0) {
2547 if (!nowait) {
2548 if (err == 0)
2549 return 0;
2550 goto nla_put_failure;
2551 } else {
2552 if (err == -EMSGSIZE)
2553 goto nla_put_failure;
2554 error = err;
2555 }
2556 }
2557 } else
2558 #endif
2559 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2560 goto nla_put_failure;
2561 }
2562
2563 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2564 goto nla_put_failure;
2565
2566 nlmsg_end(skb, nlh);
2567 return 0;
2568
2569 nla_put_failure:
2570 nlmsg_cancel(skb, nlh);
2571 return -EMSGSIZE;
2572 }
2573
2574 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2575 {
2576 struct net *net = sock_net(in_skb->sk);
2577 struct rtmsg *rtm;
2578 struct nlattr *tb[RTA_MAX+1];
2579 struct rtable *rt = NULL;
2580 struct flowi4 fl4;
2581 __be32 dst = 0;
2582 __be32 src = 0;
2583 u32 iif;
2584 int err;
2585 int mark;
2586 struct sk_buff *skb;
2587 u32 table_id = RT_TABLE_MAIN;
2588 kuid_t uid;
2589
2590 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2591 if (err < 0)
2592 goto errout;
2593
2594 rtm = nlmsg_data(nlh);
2595
2596 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2597 if (!skb) {
2598 err = -ENOBUFS;
2599 goto errout;
2600 }
2601
2602 /* Reserve room for dummy headers, this skb can pass
2603 through good chunk of routing engine.
2604 */
2605 skb_reset_mac_header(skb);
2606 skb_reset_network_header(skb);
2607
2608 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2609 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2610 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2611
2612 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2613 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2614 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2615 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2616 if (tb[RTA_UID])
2617 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2618 else
2619 uid = (iif ? INVALID_UID : current_uid());
2620
2621 memset(&fl4, 0, sizeof(fl4));
2622 fl4.daddr = dst;
2623 fl4.saddr = src;
2624 fl4.flowi4_tos = rtm->rtm_tos;
2625 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2626 fl4.flowi4_mark = mark;
2627 fl4.flowi4_uid = uid;
2628
2629 if (iif) {
2630 struct net_device *dev;
2631
2632 dev = __dev_get_by_index(net, iif);
2633 if (!dev) {
2634 err = -ENODEV;
2635 goto errout_free;
2636 }
2637
2638 skb->protocol = htons(ETH_P_IP);
2639 skb->dev = dev;
2640 skb->mark = mark;
2641 local_bh_disable();
2642 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2643 local_bh_enable();
2644
2645 rt = skb_rtable(skb);
2646 if (err == 0 && rt->dst.error)
2647 err = -rt->dst.error;
2648 } else {
2649 rt = ip_route_output_key(net, &fl4);
2650
2651 err = 0;
2652 if (IS_ERR(rt))
2653 err = PTR_ERR(rt);
2654 }
2655
2656 if (err)
2657 goto errout_free;
2658
2659 skb_dst_set(skb, &rt->dst);
2660 if (rtm->rtm_flags & RTM_F_NOTIFY)
2661 rt->rt_flags |= RTCF_NOTIFY;
2662
2663 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2664 table_id = rt->rt_table_id;
2665
2666 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2667 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2668 RTM_NEWROUTE, 0, 0);
2669 if (err < 0)
2670 goto errout_free;
2671
2672 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2673 errout:
2674 return err;
2675
2676 errout_free:
2677 kfree_skb(skb);
2678 goto errout;
2679 }
2680
2681 void ip_rt_multicast_event(struct in_device *in_dev)
2682 {
2683 rt_cache_flush(dev_net(in_dev->dev));
2684 }
2685
2686 #ifdef CONFIG_SYSCTL
2687 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2688 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2689 static int ip_rt_gc_elasticity __read_mostly = 8;
2690
2691 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2692 void __user *buffer,
2693 size_t *lenp, loff_t *ppos)
2694 {
2695 struct net *net = (struct net *)__ctl->extra1;
2696
2697 if (write) {
2698 rt_cache_flush(net);
2699 fnhe_genid_bump(net);
2700 return 0;
2701 }
2702
2703 return -EINVAL;
2704 }
2705
2706 static struct ctl_table ipv4_route_table[] = {
2707 {
2708 .procname = "gc_thresh",
2709 .data = &ipv4_dst_ops.gc_thresh,
2710 .maxlen = sizeof(int),
2711 .mode = 0644,
2712 .proc_handler = proc_dointvec,
2713 },
2714 {
2715 .procname = "max_size",
2716 .data = &ip_rt_max_size,
2717 .maxlen = sizeof(int),
2718 .mode = 0644,
2719 .proc_handler = proc_dointvec,
2720 },
2721 {
2722 /* Deprecated. Use gc_min_interval_ms */
2723
2724 .procname = "gc_min_interval",
2725 .data = &ip_rt_gc_min_interval,
2726 .maxlen = sizeof(int),
2727 .mode = 0644,
2728 .proc_handler = proc_dointvec_jiffies,
2729 },
2730 {
2731 .procname = "gc_min_interval_ms",
2732 .data = &ip_rt_gc_min_interval,
2733 .maxlen = sizeof(int),
2734 .mode = 0644,
2735 .proc_handler = proc_dointvec_ms_jiffies,
2736 },
2737 {
2738 .procname = "gc_timeout",
2739 .data = &ip_rt_gc_timeout,
2740 .maxlen = sizeof(int),
2741 .mode = 0644,
2742 .proc_handler = proc_dointvec_jiffies,
2743 },
2744 {
2745 .procname = "gc_interval",
2746 .data = &ip_rt_gc_interval,
2747 .maxlen = sizeof(int),
2748 .mode = 0644,
2749 .proc_handler = proc_dointvec_jiffies,
2750 },
2751 {
2752 .procname = "redirect_load",
2753 .data = &ip_rt_redirect_load,
2754 .maxlen = sizeof(int),
2755 .mode = 0644,
2756 .proc_handler = proc_dointvec,
2757 },
2758 {
2759 .procname = "redirect_number",
2760 .data = &ip_rt_redirect_number,
2761 .maxlen = sizeof(int),
2762 .mode = 0644,
2763 .proc_handler = proc_dointvec,
2764 },
2765 {
2766 .procname = "redirect_silence",
2767 .data = &ip_rt_redirect_silence,
2768 .maxlen = sizeof(int),
2769 .mode = 0644,
2770 .proc_handler = proc_dointvec,
2771 },
2772 {
2773 .procname = "error_cost",
2774 .data = &ip_rt_error_cost,
2775 .maxlen = sizeof(int),
2776 .mode = 0644,
2777 .proc_handler = proc_dointvec,
2778 },
2779 {
2780 .procname = "error_burst",
2781 .data = &ip_rt_error_burst,
2782 .maxlen = sizeof(int),
2783 .mode = 0644,
2784 .proc_handler = proc_dointvec,
2785 },
2786 {
2787 .procname = "gc_elasticity",
2788 .data = &ip_rt_gc_elasticity,
2789 .maxlen = sizeof(int),
2790 .mode = 0644,
2791 .proc_handler = proc_dointvec,
2792 },
2793 {
2794 .procname = "mtu_expires",
2795 .data = &ip_rt_mtu_expires,
2796 .maxlen = sizeof(int),
2797 .mode = 0644,
2798 .proc_handler = proc_dointvec_jiffies,
2799 },
2800 {
2801 .procname = "min_pmtu",
2802 .data = &ip_rt_min_pmtu,
2803 .maxlen = sizeof(int),
2804 .mode = 0644,
2805 .proc_handler = proc_dointvec,
2806 },
2807 {
2808 .procname = "min_adv_mss",
2809 .data = &ip_rt_min_advmss,
2810 .maxlen = sizeof(int),
2811 .mode = 0644,
2812 .proc_handler = proc_dointvec,
2813 },
2814 { }
2815 };
2816
2817 static struct ctl_table ipv4_route_flush_table[] = {
2818 {
2819 .procname = "flush",
2820 .maxlen = sizeof(int),
2821 .mode = 0200,
2822 .proc_handler = ipv4_sysctl_rtcache_flush,
2823 },
2824 { },
2825 };
2826
2827 static __net_init int sysctl_route_net_init(struct net *net)
2828 {
2829 struct ctl_table *tbl;
2830
2831 tbl = ipv4_route_flush_table;
2832 if (!net_eq(net, &init_net)) {
2833 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2834 if (!tbl)
2835 goto err_dup;
2836
2837 /* Don't export sysctls to unprivileged users */
2838 if (net->user_ns != &init_user_ns)
2839 tbl[0].procname = NULL;
2840 }
2841 tbl[0].extra1 = net;
2842
2843 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2844 if (!net->ipv4.route_hdr)
2845 goto err_reg;
2846 return 0;
2847
2848 err_reg:
2849 if (tbl != ipv4_route_flush_table)
2850 kfree(tbl);
2851 err_dup:
2852 return -ENOMEM;
2853 }
2854
2855 static __net_exit void sysctl_route_net_exit(struct net *net)
2856 {
2857 struct ctl_table *tbl;
2858
2859 tbl = net->ipv4.route_hdr->ctl_table_arg;
2860 unregister_net_sysctl_table(net->ipv4.route_hdr);
2861 BUG_ON(tbl == ipv4_route_flush_table);
2862 kfree(tbl);
2863 }
2864
2865 static __net_initdata struct pernet_operations sysctl_route_ops = {
2866 .init = sysctl_route_net_init,
2867 .exit = sysctl_route_net_exit,
2868 };
2869 #endif
2870
2871 static __net_init int rt_genid_init(struct net *net)
2872 {
2873 atomic_set(&net->ipv4.rt_genid, 0);
2874 atomic_set(&net->fnhe_genid, 0);
2875 get_random_bytes(&net->ipv4.dev_addr_genid,
2876 sizeof(net->ipv4.dev_addr_genid));
2877 return 0;
2878 }
2879
2880 static __net_initdata struct pernet_operations rt_genid_ops = {
2881 .init = rt_genid_init,
2882 };
2883
2884 static int __net_init ipv4_inetpeer_init(struct net *net)
2885 {
2886 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2887
2888 if (!bp)
2889 return -ENOMEM;
2890 inet_peer_base_init(bp);
2891 net->ipv4.peers = bp;
2892 return 0;
2893 }
2894
2895 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2896 {
2897 struct inet_peer_base *bp = net->ipv4.peers;
2898
2899 net->ipv4.peers = NULL;
2900 inetpeer_invalidate_tree(bp);
2901 kfree(bp);
2902 }
2903
2904 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2905 .init = ipv4_inetpeer_init,
2906 .exit = ipv4_inetpeer_exit,
2907 };
2908
2909 #ifdef CONFIG_IP_ROUTE_CLASSID
2910 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2911 #endif /* CONFIG_IP_ROUTE_CLASSID */
2912
2913 int __init ip_rt_init(void)
2914 {
2915 int rc = 0;
2916 int cpu;
2917
2918 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2919 if (!ip_idents)
2920 panic("IP: failed to allocate ip_idents\n");
2921
2922 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2923
2924 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2925 if (!ip_tstamps)
2926 panic("IP: failed to allocate ip_tstamps\n");
2927
2928 for_each_possible_cpu(cpu) {
2929 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2930
2931 INIT_LIST_HEAD(&ul->head);
2932 spin_lock_init(&ul->lock);
2933 }
2934 #ifdef CONFIG_IP_ROUTE_CLASSID
2935 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2936 if (!ip_rt_acct)
2937 panic("IP: failed to allocate ip_rt_acct\n");
2938 #endif
2939
2940 ipv4_dst_ops.kmem_cachep =
2941 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2942 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2943
2944 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2945
2946 if (dst_entries_init(&ipv4_dst_ops) < 0)
2947 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2948
2949 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2950 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2951
2952 ipv4_dst_ops.gc_thresh = ~0;
2953 ip_rt_max_size = INT_MAX;
2954
2955 devinet_init();
2956 ip_fib_init();
2957
2958 if (ip_rt_proc_init())
2959 pr_err("Unable to create route proc files\n");
2960 #ifdef CONFIG_XFRM
2961 xfrm_init();
2962 xfrm4_init();
2963 #endif
2964 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2965
2966 #ifdef CONFIG_SYSCTL
2967 register_pernet_subsys(&sysctl_route_ops);
2968 #endif
2969 register_pernet_subsys(&rt_genid_ops);
2970 register_pernet_subsys(&ipv4_inetpeer_ops);
2971 return rc;
2972 }
2973
2974 #ifdef CONFIG_SYSCTL
2975 /*
2976 * We really need to sanitize the damn ipv4 init order, then all
2977 * this nonsense will go away.
2978 */
2979 void __init ip_static_sysctl_init(void)
2980 {
2981 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2982 }
2983 #endif
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