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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[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
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 struct in_device *in_dev,
1762 __be32 daddr, __be32 saddr, u32 tos)
1763 {
1764 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1765 if (res->fi && res->fi->fib_nhs > 1) {
1766 int h;
1767
1768 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1769 h = ip_multipath_icmp_hash(skb);
1770 else
1771 h = fib_multipath_hash(saddr, daddr);
1772 fib_select_multipath(res, h);
1773 }
1774 #endif
1775
1776 /* create a routing cache entry */
1777 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1778 }
1779
1780 /*
1781 * NOTE. We drop all the packets that has local source
1782 * addresses, because every properly looped back packet
1783 * must have correct destination already attached by output routine.
1784 *
1785 * Such approach solves two big problems:
1786 * 1. Not simplex devices are handled properly.
1787 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1788 * called with rcu_read_lock()
1789 */
1790
1791 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1792 u8 tos, struct net_device *dev)
1793 {
1794 struct fib_result res;
1795 struct in_device *in_dev = __in_dev_get_rcu(dev);
1796 struct ip_tunnel_info *tun_info;
1797 struct flowi4 fl4;
1798 unsigned int flags = 0;
1799 u32 itag = 0;
1800 struct rtable *rth;
1801 int err = -EINVAL;
1802 struct net *net = dev_net(dev);
1803 bool do_cache;
1804
1805 /* IP on this device is disabled. */
1806
1807 if (!in_dev)
1808 goto out;
1809
1810 /* Check for the most weird martians, which can be not detected
1811 by fib_lookup.
1812 */
1813
1814 tun_info = skb_tunnel_info(skb);
1815 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1816 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1817 else
1818 fl4.flowi4_tun_key.tun_id = 0;
1819 skb_dst_drop(skb);
1820
1821 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1822 goto martian_source;
1823
1824 res.fi = NULL;
1825 res.table = NULL;
1826 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1827 goto brd_input;
1828
1829 /* Accept zero addresses only to limited broadcast;
1830 * I even do not know to fix it or not. Waiting for complains :-)
1831 */
1832 if (ipv4_is_zeronet(saddr))
1833 goto martian_source;
1834
1835 if (ipv4_is_zeronet(daddr))
1836 goto martian_destination;
1837
1838 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1839 * and call it once if daddr or/and saddr are loopback addresses
1840 */
1841 if (ipv4_is_loopback(daddr)) {
1842 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1843 goto martian_destination;
1844 } else if (ipv4_is_loopback(saddr)) {
1845 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1846 goto martian_source;
1847 }
1848
1849 /*
1850 * Now we are ready to route packet.
1851 */
1852 fl4.flowi4_oif = 0;
1853 fl4.flowi4_iif = dev->ifindex;
1854 fl4.flowi4_mark = skb->mark;
1855 fl4.flowi4_tos = tos;
1856 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1857 fl4.flowi4_flags = 0;
1858 fl4.daddr = daddr;
1859 fl4.saddr = saddr;
1860 err = fib_lookup(net, &fl4, &res, 0);
1861 if (err != 0) {
1862 if (!IN_DEV_FORWARD(in_dev))
1863 err = -EHOSTUNREACH;
1864 goto no_route;
1865 }
1866
1867 if (res.type == RTN_BROADCAST)
1868 goto brd_input;
1869
1870 if (res.type == RTN_LOCAL) {
1871 err = fib_validate_source(skb, saddr, daddr, tos,
1872 0, dev, in_dev, &itag);
1873 if (err < 0)
1874 goto martian_source;
1875 goto local_input;
1876 }
1877
1878 if (!IN_DEV_FORWARD(in_dev)) {
1879 err = -EHOSTUNREACH;
1880 goto no_route;
1881 }
1882 if (res.type != RTN_UNICAST)
1883 goto martian_destination;
1884
1885 err = ip_mkroute_input(skb, &res, in_dev, daddr, saddr, tos);
1886 out: return err;
1887
1888 brd_input:
1889 if (skb->protocol != htons(ETH_P_IP))
1890 goto e_inval;
1891
1892 if (!ipv4_is_zeronet(saddr)) {
1893 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1894 in_dev, &itag);
1895 if (err < 0)
1896 goto martian_source;
1897 }
1898 flags |= RTCF_BROADCAST;
1899 res.type = RTN_BROADCAST;
1900 RT_CACHE_STAT_INC(in_brd);
1901
1902 local_input:
1903 do_cache = false;
1904 if (res.fi) {
1905 if (!itag) {
1906 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1907 if (rt_cache_valid(rth)) {
1908 skb_dst_set_noref(skb, &rth->dst);
1909 err = 0;
1910 goto out;
1911 }
1912 do_cache = true;
1913 }
1914 }
1915
1916 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
1917 flags | RTCF_LOCAL, res.type,
1918 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1919 if (!rth)
1920 goto e_nobufs;
1921
1922 rth->dst.output= ip_rt_bug;
1923 #ifdef CONFIG_IP_ROUTE_CLASSID
1924 rth->dst.tclassid = itag;
1925 #endif
1926 rth->rt_is_input = 1;
1927 if (res.table)
1928 rth->rt_table_id = res.table->tb_id;
1929
1930 RT_CACHE_STAT_INC(in_slow_tot);
1931 if (res.type == RTN_UNREACHABLE) {
1932 rth->dst.input= ip_error;
1933 rth->dst.error= -err;
1934 rth->rt_flags &= ~RTCF_LOCAL;
1935 }
1936
1937 if (do_cache) {
1938 struct fib_nh *nh = &FIB_RES_NH(res);
1939
1940 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1941 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1942 WARN_ON(rth->dst.input == lwtunnel_input);
1943 rth->dst.lwtstate->orig_input = rth->dst.input;
1944 rth->dst.input = lwtunnel_input;
1945 }
1946
1947 if (unlikely(!rt_cache_route(nh, rth))) {
1948 rth->dst.flags |= DST_NOCACHE;
1949 rt_add_uncached_list(rth);
1950 }
1951 }
1952 skb_dst_set(skb, &rth->dst);
1953 err = 0;
1954 goto out;
1955
1956 no_route:
1957 RT_CACHE_STAT_INC(in_no_route);
1958 res.type = RTN_UNREACHABLE;
1959 res.fi = NULL;
1960 res.table = NULL;
1961 goto local_input;
1962
1963 /*
1964 * Do not cache martian addresses: they should be logged (RFC1812)
1965 */
1966 martian_destination:
1967 RT_CACHE_STAT_INC(in_martian_dst);
1968 #ifdef CONFIG_IP_ROUTE_VERBOSE
1969 if (IN_DEV_LOG_MARTIANS(in_dev))
1970 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1971 &daddr, &saddr, dev->name);
1972 #endif
1973
1974 e_inval:
1975 err = -EINVAL;
1976 goto out;
1977
1978 e_nobufs:
1979 err = -ENOBUFS;
1980 goto out;
1981
1982 martian_source:
1983 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1984 goto out;
1985 }
1986
1987 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1988 u8 tos, struct net_device *dev)
1989 {
1990 int res;
1991
1992 rcu_read_lock();
1993
1994 /* Multicast recognition logic is moved from route cache to here.
1995 The problem was that too many Ethernet cards have broken/missing
1996 hardware multicast filters :-( As result the host on multicasting
1997 network acquires a lot of useless route cache entries, sort of
1998 SDR messages from all the world. Now we try to get rid of them.
1999 Really, provided software IP multicast filter is organized
2000 reasonably (at least, hashed), it does not result in a slowdown
2001 comparing with route cache reject entries.
2002 Note, that multicast routers are not affected, because
2003 route cache entry is created eventually.
2004 */
2005 if (ipv4_is_multicast(daddr)) {
2006 struct in_device *in_dev = __in_dev_get_rcu(dev);
2007 int our = 0;
2008
2009 if (in_dev)
2010 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2011 ip_hdr(skb)->protocol);
2012
2013 /* check l3 master if no match yet */
2014 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2015 struct in_device *l3_in_dev;
2016
2017 l3_in_dev = __in_dev_get_rcu(skb->dev);
2018 if (l3_in_dev)
2019 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2020 ip_hdr(skb)->protocol);
2021 }
2022
2023 res = -EINVAL;
2024 if (our
2025 #ifdef CONFIG_IP_MROUTE
2026 ||
2027 (!ipv4_is_local_multicast(daddr) &&
2028 IN_DEV_MFORWARD(in_dev))
2029 #endif
2030 ) {
2031 res = ip_route_input_mc(skb, daddr, saddr,
2032 tos, dev, our);
2033 }
2034 rcu_read_unlock();
2035 return res;
2036 }
2037 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2038 rcu_read_unlock();
2039 return res;
2040 }
2041 EXPORT_SYMBOL(ip_route_input_noref);
2042
2043 /* called with rcu_read_lock() */
2044 static struct rtable *__mkroute_output(const struct fib_result *res,
2045 const struct flowi4 *fl4, int orig_oif,
2046 struct net_device *dev_out,
2047 unsigned int flags)
2048 {
2049 struct fib_info *fi = res->fi;
2050 struct fib_nh_exception *fnhe;
2051 struct in_device *in_dev;
2052 u16 type = res->type;
2053 struct rtable *rth;
2054 bool do_cache;
2055
2056 in_dev = __in_dev_get_rcu(dev_out);
2057 if (!in_dev)
2058 return ERR_PTR(-EINVAL);
2059
2060 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2061 if (ipv4_is_loopback(fl4->saddr) &&
2062 !(dev_out->flags & IFF_LOOPBACK) &&
2063 !netif_is_l3_master(dev_out))
2064 return ERR_PTR(-EINVAL);
2065
2066 if (ipv4_is_lbcast(fl4->daddr))
2067 type = RTN_BROADCAST;
2068 else if (ipv4_is_multicast(fl4->daddr))
2069 type = RTN_MULTICAST;
2070 else if (ipv4_is_zeronet(fl4->daddr))
2071 return ERR_PTR(-EINVAL);
2072
2073 if (dev_out->flags & IFF_LOOPBACK)
2074 flags |= RTCF_LOCAL;
2075
2076 do_cache = true;
2077 if (type == RTN_BROADCAST) {
2078 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2079 fi = NULL;
2080 } else if (type == RTN_MULTICAST) {
2081 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2082 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2083 fl4->flowi4_proto))
2084 flags &= ~RTCF_LOCAL;
2085 else
2086 do_cache = false;
2087 /* If multicast route do not exist use
2088 * default one, but do not gateway in this case.
2089 * Yes, it is hack.
2090 */
2091 if (fi && res->prefixlen < 4)
2092 fi = NULL;
2093 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2094 (orig_oif != dev_out->ifindex)) {
2095 /* For local routes that require a particular output interface
2096 * we do not want to cache the result. Caching the result
2097 * causes incorrect behaviour when there are multiple source
2098 * addresses on the interface, the end result being that if the
2099 * intended recipient is waiting on that interface for the
2100 * packet he won't receive it because it will be delivered on
2101 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2102 * be set to the loopback interface as well.
2103 */
2104 fi = NULL;
2105 }
2106
2107 fnhe = NULL;
2108 do_cache &= fi != NULL;
2109 if (do_cache) {
2110 struct rtable __rcu **prth;
2111 struct fib_nh *nh = &FIB_RES_NH(*res);
2112
2113 fnhe = find_exception(nh, fl4->daddr);
2114 if (fnhe) {
2115 prth = &fnhe->fnhe_rth_output;
2116 rth = rcu_dereference(*prth);
2117 if (rth && rth->dst.expires &&
2118 time_after(jiffies, rth->dst.expires)) {
2119 ip_del_fnhe(nh, fl4->daddr);
2120 fnhe = NULL;
2121 } else {
2122 goto rt_cache;
2123 }
2124 }
2125
2126 if (unlikely(fl4->flowi4_flags &
2127 FLOWI_FLAG_KNOWN_NH &&
2128 !(nh->nh_gw &&
2129 nh->nh_scope == RT_SCOPE_LINK))) {
2130 do_cache = false;
2131 goto add;
2132 }
2133 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2134 rth = rcu_dereference(*prth);
2135
2136 rt_cache:
2137 if (rt_cache_valid(rth)) {
2138 dst_hold(&rth->dst);
2139 return rth;
2140 }
2141 }
2142
2143 add:
2144 rth = rt_dst_alloc(dev_out, flags, type,
2145 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2146 IN_DEV_CONF_GET(in_dev, NOXFRM),
2147 do_cache);
2148 if (!rth)
2149 return ERR_PTR(-ENOBUFS);
2150
2151 rth->rt_iif = orig_oif ? : 0;
2152 if (res->table)
2153 rth->rt_table_id = res->table->tb_id;
2154
2155 RT_CACHE_STAT_INC(out_slow_tot);
2156
2157 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2158 if (flags & RTCF_LOCAL &&
2159 !(dev_out->flags & IFF_LOOPBACK)) {
2160 rth->dst.output = ip_mc_output;
2161 RT_CACHE_STAT_INC(out_slow_mc);
2162 }
2163 #ifdef CONFIG_IP_MROUTE
2164 if (type == RTN_MULTICAST) {
2165 if (IN_DEV_MFORWARD(in_dev) &&
2166 !ipv4_is_local_multicast(fl4->daddr)) {
2167 rth->dst.input = ip_mr_input;
2168 rth->dst.output = ip_mc_output;
2169 }
2170 }
2171 #endif
2172 }
2173
2174 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2175 set_lwt_redirect(rth);
2176
2177 return rth;
2178 }
2179
2180 /*
2181 * Major route resolver routine.
2182 */
2183
2184 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2185 int mp_hash)
2186 {
2187 struct net_device *dev_out = NULL;
2188 __u8 tos = RT_FL_TOS(fl4);
2189 unsigned int flags = 0;
2190 struct fib_result res;
2191 struct rtable *rth;
2192 int orig_oif;
2193 int err = -ENETUNREACH;
2194
2195 res.tclassid = 0;
2196 res.fi = NULL;
2197 res.table = NULL;
2198
2199 orig_oif = fl4->flowi4_oif;
2200
2201 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2202 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2203 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2204 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2205
2206 rcu_read_lock();
2207 if (fl4->saddr) {
2208 rth = ERR_PTR(-EINVAL);
2209 if (ipv4_is_multicast(fl4->saddr) ||
2210 ipv4_is_lbcast(fl4->saddr) ||
2211 ipv4_is_zeronet(fl4->saddr))
2212 goto out;
2213
2214 /* I removed check for oif == dev_out->oif here.
2215 It was wrong for two reasons:
2216 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2217 is assigned to multiple interfaces.
2218 2. Moreover, we are allowed to send packets with saddr
2219 of another iface. --ANK
2220 */
2221
2222 if (fl4->flowi4_oif == 0 &&
2223 (ipv4_is_multicast(fl4->daddr) ||
2224 ipv4_is_lbcast(fl4->daddr))) {
2225 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2226 dev_out = __ip_dev_find(net, fl4->saddr, false);
2227 if (!dev_out)
2228 goto out;
2229
2230 /* Special hack: user can direct multicasts
2231 and limited broadcast via necessary interface
2232 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2233 This hack is not just for fun, it allows
2234 vic,vat and friends to work.
2235 They bind socket to loopback, set ttl to zero
2236 and expect that it will work.
2237 From the viewpoint of routing cache they are broken,
2238 because we are not allowed to build multicast path
2239 with loopback source addr (look, routing cache
2240 cannot know, that ttl is zero, so that packet
2241 will not leave this host and route is valid).
2242 Luckily, this hack is good workaround.
2243 */
2244
2245 fl4->flowi4_oif = dev_out->ifindex;
2246 goto make_route;
2247 }
2248
2249 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2250 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2251 if (!__ip_dev_find(net, fl4->saddr, false))
2252 goto out;
2253 }
2254 }
2255
2256
2257 if (fl4->flowi4_oif) {
2258 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2259 rth = ERR_PTR(-ENODEV);
2260 if (!dev_out)
2261 goto out;
2262
2263 /* RACE: Check return value of inet_select_addr instead. */
2264 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2265 rth = ERR_PTR(-ENETUNREACH);
2266 goto out;
2267 }
2268 if (ipv4_is_local_multicast(fl4->daddr) ||
2269 ipv4_is_lbcast(fl4->daddr) ||
2270 fl4->flowi4_proto == IPPROTO_IGMP) {
2271 if (!fl4->saddr)
2272 fl4->saddr = inet_select_addr(dev_out, 0,
2273 RT_SCOPE_LINK);
2274 goto make_route;
2275 }
2276 if (!fl4->saddr) {
2277 if (ipv4_is_multicast(fl4->daddr))
2278 fl4->saddr = inet_select_addr(dev_out, 0,
2279 fl4->flowi4_scope);
2280 else if (!fl4->daddr)
2281 fl4->saddr = inet_select_addr(dev_out, 0,
2282 RT_SCOPE_HOST);
2283 }
2284 }
2285
2286 if (!fl4->daddr) {
2287 fl4->daddr = fl4->saddr;
2288 if (!fl4->daddr)
2289 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2290 dev_out = net->loopback_dev;
2291 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2292 res.type = RTN_LOCAL;
2293 flags |= RTCF_LOCAL;
2294 goto make_route;
2295 }
2296
2297 err = fib_lookup(net, fl4, &res, 0);
2298 if (err) {
2299 res.fi = NULL;
2300 res.table = NULL;
2301 if (fl4->flowi4_oif &&
2302 (ipv4_is_multicast(fl4->daddr) ||
2303 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2304 /* Apparently, routing tables are wrong. Assume,
2305 that the destination is on link.
2306
2307 WHY? DW.
2308 Because we are allowed to send to iface
2309 even if it has NO routes and NO assigned
2310 addresses. When oif is specified, routing
2311 tables are looked up with only one purpose:
2312 to catch if destination is gatewayed, rather than
2313 direct. Moreover, if MSG_DONTROUTE is set,
2314 we send packet, ignoring both routing tables
2315 and ifaddr state. --ANK
2316
2317
2318 We could make it even if oif is unknown,
2319 likely IPv6, but we do not.
2320 */
2321
2322 if (fl4->saddr == 0)
2323 fl4->saddr = inet_select_addr(dev_out, 0,
2324 RT_SCOPE_LINK);
2325 res.type = RTN_UNICAST;
2326 goto make_route;
2327 }
2328 rth = ERR_PTR(err);
2329 goto out;
2330 }
2331
2332 if (res.type == RTN_LOCAL) {
2333 if (!fl4->saddr) {
2334 if (res.fi->fib_prefsrc)
2335 fl4->saddr = res.fi->fib_prefsrc;
2336 else
2337 fl4->saddr = fl4->daddr;
2338 }
2339
2340 /* L3 master device is the loopback for that domain */
2341 dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev;
2342 fl4->flowi4_oif = dev_out->ifindex;
2343 flags |= RTCF_LOCAL;
2344 goto make_route;
2345 }
2346
2347 fib_select_path(net, &res, fl4, mp_hash);
2348
2349 dev_out = FIB_RES_DEV(res);
2350 fl4->flowi4_oif = dev_out->ifindex;
2351
2352
2353 make_route:
2354 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2355
2356 out:
2357 rcu_read_unlock();
2358 return rth;
2359 }
2360 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2361
2362 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2363 {
2364 return NULL;
2365 }
2366
2367 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2368 {
2369 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2370
2371 return mtu ? : dst->dev->mtu;
2372 }
2373
2374 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2375 struct sk_buff *skb, u32 mtu)
2376 {
2377 }
2378
2379 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2380 struct sk_buff *skb)
2381 {
2382 }
2383
2384 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2385 unsigned long old)
2386 {
2387 return NULL;
2388 }
2389
2390 static struct dst_ops ipv4_dst_blackhole_ops = {
2391 .family = AF_INET,
2392 .check = ipv4_blackhole_dst_check,
2393 .mtu = ipv4_blackhole_mtu,
2394 .default_advmss = ipv4_default_advmss,
2395 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2396 .redirect = ipv4_rt_blackhole_redirect,
2397 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2398 .neigh_lookup = ipv4_neigh_lookup,
2399 };
2400
2401 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2402 {
2403 struct rtable *ort = (struct rtable *) dst_orig;
2404 struct rtable *rt;
2405
2406 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2407 if (rt) {
2408 struct dst_entry *new = &rt->dst;
2409
2410 new->__use = 1;
2411 new->input = dst_discard;
2412 new->output = dst_discard_out;
2413
2414 new->dev = ort->dst.dev;
2415 if (new->dev)
2416 dev_hold(new->dev);
2417
2418 rt->rt_is_input = ort->rt_is_input;
2419 rt->rt_iif = ort->rt_iif;
2420 rt->rt_pmtu = ort->rt_pmtu;
2421
2422 rt->rt_genid = rt_genid_ipv4(net);
2423 rt->rt_flags = ort->rt_flags;
2424 rt->rt_type = ort->rt_type;
2425 rt->rt_gateway = ort->rt_gateway;
2426 rt->rt_uses_gateway = ort->rt_uses_gateway;
2427
2428 INIT_LIST_HEAD(&rt->rt_uncached);
2429 dst_free(new);
2430 }
2431
2432 dst_release(dst_orig);
2433
2434 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2435 }
2436
2437 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2438 const struct sock *sk)
2439 {
2440 struct rtable *rt = __ip_route_output_key(net, flp4);
2441
2442 if (IS_ERR(rt))
2443 return rt;
2444
2445 if (flp4->flowi4_proto)
2446 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2447 flowi4_to_flowi(flp4),
2448 sk, 0);
2449
2450 return rt;
2451 }
2452 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2453
2454 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2455 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2456 u32 seq, int event)
2457 {
2458 struct rtable *rt = skb_rtable(skb);
2459 struct rtmsg *r;
2460 struct nlmsghdr *nlh;
2461 unsigned long expires = 0;
2462 u32 error;
2463 u32 metrics[RTAX_MAX];
2464
2465 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), 0);
2466 if (!nlh)
2467 return -EMSGSIZE;
2468
2469 r = nlmsg_data(nlh);
2470 r->rtm_family = AF_INET;
2471 r->rtm_dst_len = 32;
2472 r->rtm_src_len = 0;
2473 r->rtm_tos = fl4->flowi4_tos;
2474 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2475 if (nla_put_u32(skb, RTA_TABLE, table_id))
2476 goto nla_put_failure;
2477 r->rtm_type = rt->rt_type;
2478 r->rtm_scope = RT_SCOPE_UNIVERSE;
2479 r->rtm_protocol = RTPROT_UNSPEC;
2480 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2481 if (rt->rt_flags & RTCF_NOTIFY)
2482 r->rtm_flags |= RTM_F_NOTIFY;
2483 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2484 r->rtm_flags |= RTCF_DOREDIRECT;
2485
2486 if (nla_put_in_addr(skb, RTA_DST, dst))
2487 goto nla_put_failure;
2488 if (src) {
2489 r->rtm_src_len = 32;
2490 if (nla_put_in_addr(skb, RTA_SRC, src))
2491 goto nla_put_failure;
2492 }
2493 if (rt->dst.dev &&
2494 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2495 goto nla_put_failure;
2496 #ifdef CONFIG_IP_ROUTE_CLASSID
2497 if (rt->dst.tclassid &&
2498 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2499 goto nla_put_failure;
2500 #endif
2501 if (!rt_is_input_route(rt) &&
2502 fl4->saddr != src) {
2503 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2504 goto nla_put_failure;
2505 }
2506 if (rt->rt_uses_gateway &&
2507 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2508 goto nla_put_failure;
2509
2510 expires = rt->dst.expires;
2511 if (expires) {
2512 unsigned long now = jiffies;
2513
2514 if (time_before(now, expires))
2515 expires -= now;
2516 else
2517 expires = 0;
2518 }
2519
2520 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2521 if (rt->rt_pmtu && expires)
2522 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2523 if (rtnetlink_put_metrics(skb, metrics) < 0)
2524 goto nla_put_failure;
2525
2526 if (fl4->flowi4_mark &&
2527 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2528 goto nla_put_failure;
2529
2530 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2531 nla_put_u32(skb, RTA_UID,
2532 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2533 goto nla_put_failure;
2534
2535 error = rt->dst.error;
2536
2537 if (rt_is_input_route(rt)) {
2538 #ifdef CONFIG_IP_MROUTE
2539 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2540 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2541 int err = ipmr_get_route(net, skb,
2542 fl4->saddr, fl4->daddr,
2543 r, portid);
2544
2545 if (err <= 0) {
2546 if (err == 0)
2547 return 0;
2548 goto nla_put_failure;
2549 }
2550 } else
2551 #endif
2552 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2553 goto nla_put_failure;
2554 }
2555
2556 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2557 goto nla_put_failure;
2558
2559 nlmsg_end(skb, nlh);
2560 return 0;
2561
2562 nla_put_failure:
2563 nlmsg_cancel(skb, nlh);
2564 return -EMSGSIZE;
2565 }
2566
2567 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2568 {
2569 struct net *net = sock_net(in_skb->sk);
2570 struct rtmsg *rtm;
2571 struct nlattr *tb[RTA_MAX+1];
2572 struct rtable *rt = NULL;
2573 struct flowi4 fl4;
2574 __be32 dst = 0;
2575 __be32 src = 0;
2576 u32 iif;
2577 int err;
2578 int mark;
2579 struct sk_buff *skb;
2580 u32 table_id = RT_TABLE_MAIN;
2581 kuid_t uid;
2582
2583 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2584 if (err < 0)
2585 goto errout;
2586
2587 rtm = nlmsg_data(nlh);
2588
2589 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2590 if (!skb) {
2591 err = -ENOBUFS;
2592 goto errout;
2593 }
2594
2595 /* Reserve room for dummy headers, this skb can pass
2596 through good chunk of routing engine.
2597 */
2598 skb_reset_mac_header(skb);
2599 skb_reset_network_header(skb);
2600
2601 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2602 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2603 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2604
2605 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2606 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2607 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2608 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2609 if (tb[RTA_UID])
2610 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2611 else
2612 uid = (iif ? INVALID_UID : current_uid());
2613
2614 memset(&fl4, 0, sizeof(fl4));
2615 fl4.daddr = dst;
2616 fl4.saddr = src;
2617 fl4.flowi4_tos = rtm->rtm_tos;
2618 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2619 fl4.flowi4_mark = mark;
2620 fl4.flowi4_uid = uid;
2621
2622 if (iif) {
2623 struct net_device *dev;
2624
2625 dev = __dev_get_by_index(net, iif);
2626 if (!dev) {
2627 err = -ENODEV;
2628 goto errout_free;
2629 }
2630
2631 skb->protocol = htons(ETH_P_IP);
2632 skb->dev = dev;
2633 skb->mark = mark;
2634 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2635
2636 rt = skb_rtable(skb);
2637 if (err == 0 && rt->dst.error)
2638 err = -rt->dst.error;
2639 } else {
2640 rt = ip_route_output_key(net, &fl4);
2641
2642 err = 0;
2643 if (IS_ERR(rt))
2644 err = PTR_ERR(rt);
2645 }
2646
2647 if (err)
2648 goto errout_free;
2649
2650 skb_dst_set(skb, &rt->dst);
2651 if (rtm->rtm_flags & RTM_F_NOTIFY)
2652 rt->rt_flags |= RTCF_NOTIFY;
2653
2654 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2655 table_id = rt->rt_table_id;
2656
2657 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2658 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2659 RTM_NEWROUTE);
2660 if (err < 0)
2661 goto errout_free;
2662
2663 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2664 errout:
2665 return err;
2666
2667 errout_free:
2668 kfree_skb(skb);
2669 goto errout;
2670 }
2671
2672 void ip_rt_multicast_event(struct in_device *in_dev)
2673 {
2674 rt_cache_flush(dev_net(in_dev->dev));
2675 }
2676
2677 #ifdef CONFIG_SYSCTL
2678 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2679 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2680 static int ip_rt_gc_elasticity __read_mostly = 8;
2681
2682 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2683 void __user *buffer,
2684 size_t *lenp, loff_t *ppos)
2685 {
2686 struct net *net = (struct net *)__ctl->extra1;
2687
2688 if (write) {
2689 rt_cache_flush(net);
2690 fnhe_genid_bump(net);
2691 return 0;
2692 }
2693
2694 return -EINVAL;
2695 }
2696
2697 static struct ctl_table ipv4_route_table[] = {
2698 {
2699 .procname = "gc_thresh",
2700 .data = &ipv4_dst_ops.gc_thresh,
2701 .maxlen = sizeof(int),
2702 .mode = 0644,
2703 .proc_handler = proc_dointvec,
2704 },
2705 {
2706 .procname = "max_size",
2707 .data = &ip_rt_max_size,
2708 .maxlen = sizeof(int),
2709 .mode = 0644,
2710 .proc_handler = proc_dointvec,
2711 },
2712 {
2713 /* Deprecated. Use gc_min_interval_ms */
2714
2715 .procname = "gc_min_interval",
2716 .data = &ip_rt_gc_min_interval,
2717 .maxlen = sizeof(int),
2718 .mode = 0644,
2719 .proc_handler = proc_dointvec_jiffies,
2720 },
2721 {
2722 .procname = "gc_min_interval_ms",
2723 .data = &ip_rt_gc_min_interval,
2724 .maxlen = sizeof(int),
2725 .mode = 0644,
2726 .proc_handler = proc_dointvec_ms_jiffies,
2727 },
2728 {
2729 .procname = "gc_timeout",
2730 .data = &ip_rt_gc_timeout,
2731 .maxlen = sizeof(int),
2732 .mode = 0644,
2733 .proc_handler = proc_dointvec_jiffies,
2734 },
2735 {
2736 .procname = "gc_interval",
2737 .data = &ip_rt_gc_interval,
2738 .maxlen = sizeof(int),
2739 .mode = 0644,
2740 .proc_handler = proc_dointvec_jiffies,
2741 },
2742 {
2743 .procname = "redirect_load",
2744 .data = &ip_rt_redirect_load,
2745 .maxlen = sizeof(int),
2746 .mode = 0644,
2747 .proc_handler = proc_dointvec,
2748 },
2749 {
2750 .procname = "redirect_number",
2751 .data = &ip_rt_redirect_number,
2752 .maxlen = sizeof(int),
2753 .mode = 0644,
2754 .proc_handler = proc_dointvec,
2755 },
2756 {
2757 .procname = "redirect_silence",
2758 .data = &ip_rt_redirect_silence,
2759 .maxlen = sizeof(int),
2760 .mode = 0644,
2761 .proc_handler = proc_dointvec,
2762 },
2763 {
2764 .procname = "error_cost",
2765 .data = &ip_rt_error_cost,
2766 .maxlen = sizeof(int),
2767 .mode = 0644,
2768 .proc_handler = proc_dointvec,
2769 },
2770 {
2771 .procname = "error_burst",
2772 .data = &ip_rt_error_burst,
2773 .maxlen = sizeof(int),
2774 .mode = 0644,
2775 .proc_handler = proc_dointvec,
2776 },
2777 {
2778 .procname = "gc_elasticity",
2779 .data = &ip_rt_gc_elasticity,
2780 .maxlen = sizeof(int),
2781 .mode = 0644,
2782 .proc_handler = proc_dointvec,
2783 },
2784 {
2785 .procname = "mtu_expires",
2786 .data = &ip_rt_mtu_expires,
2787 .maxlen = sizeof(int),
2788 .mode = 0644,
2789 .proc_handler = proc_dointvec_jiffies,
2790 },
2791 {
2792 .procname = "min_pmtu",
2793 .data = &ip_rt_min_pmtu,
2794 .maxlen = sizeof(int),
2795 .mode = 0644,
2796 .proc_handler = proc_dointvec,
2797 },
2798 {
2799 .procname = "min_adv_mss",
2800 .data = &ip_rt_min_advmss,
2801 .maxlen = sizeof(int),
2802 .mode = 0644,
2803 .proc_handler = proc_dointvec,
2804 },
2805 { }
2806 };
2807
2808 static struct ctl_table ipv4_route_flush_table[] = {
2809 {
2810 .procname = "flush",
2811 .maxlen = sizeof(int),
2812 .mode = 0200,
2813 .proc_handler = ipv4_sysctl_rtcache_flush,
2814 },
2815 { },
2816 };
2817
2818 static __net_init int sysctl_route_net_init(struct net *net)
2819 {
2820 struct ctl_table *tbl;
2821
2822 tbl = ipv4_route_flush_table;
2823 if (!net_eq(net, &init_net)) {
2824 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2825 if (!tbl)
2826 goto err_dup;
2827
2828 /* Don't export sysctls to unprivileged users */
2829 if (net->user_ns != &init_user_ns)
2830 tbl[0].procname = NULL;
2831 }
2832 tbl[0].extra1 = net;
2833
2834 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2835 if (!net->ipv4.route_hdr)
2836 goto err_reg;
2837 return 0;
2838
2839 err_reg:
2840 if (tbl != ipv4_route_flush_table)
2841 kfree(tbl);
2842 err_dup:
2843 return -ENOMEM;
2844 }
2845
2846 static __net_exit void sysctl_route_net_exit(struct net *net)
2847 {
2848 struct ctl_table *tbl;
2849
2850 tbl = net->ipv4.route_hdr->ctl_table_arg;
2851 unregister_net_sysctl_table(net->ipv4.route_hdr);
2852 BUG_ON(tbl == ipv4_route_flush_table);
2853 kfree(tbl);
2854 }
2855
2856 static __net_initdata struct pernet_operations sysctl_route_ops = {
2857 .init = sysctl_route_net_init,
2858 .exit = sysctl_route_net_exit,
2859 };
2860 #endif
2861
2862 static __net_init int rt_genid_init(struct net *net)
2863 {
2864 atomic_set(&net->ipv4.rt_genid, 0);
2865 atomic_set(&net->fnhe_genid, 0);
2866 get_random_bytes(&net->ipv4.dev_addr_genid,
2867 sizeof(net->ipv4.dev_addr_genid));
2868 return 0;
2869 }
2870
2871 static __net_initdata struct pernet_operations rt_genid_ops = {
2872 .init = rt_genid_init,
2873 };
2874
2875 static int __net_init ipv4_inetpeer_init(struct net *net)
2876 {
2877 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2878
2879 if (!bp)
2880 return -ENOMEM;
2881 inet_peer_base_init(bp);
2882 net->ipv4.peers = bp;
2883 return 0;
2884 }
2885
2886 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2887 {
2888 struct inet_peer_base *bp = net->ipv4.peers;
2889
2890 net->ipv4.peers = NULL;
2891 inetpeer_invalidate_tree(bp);
2892 kfree(bp);
2893 }
2894
2895 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2896 .init = ipv4_inetpeer_init,
2897 .exit = ipv4_inetpeer_exit,
2898 };
2899
2900 #ifdef CONFIG_IP_ROUTE_CLASSID
2901 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2902 #endif /* CONFIG_IP_ROUTE_CLASSID */
2903
2904 int __init ip_rt_init(void)
2905 {
2906 int rc = 0;
2907 int cpu;
2908
2909 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2910 if (!ip_idents)
2911 panic("IP: failed to allocate ip_idents\n");
2912
2913 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2914
2915 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2916 if (!ip_tstamps)
2917 panic("IP: failed to allocate ip_tstamps\n");
2918
2919 for_each_possible_cpu(cpu) {
2920 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2921
2922 INIT_LIST_HEAD(&ul->head);
2923 spin_lock_init(&ul->lock);
2924 }
2925 #ifdef CONFIG_IP_ROUTE_CLASSID
2926 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2927 if (!ip_rt_acct)
2928 panic("IP: failed to allocate ip_rt_acct\n");
2929 #endif
2930
2931 ipv4_dst_ops.kmem_cachep =
2932 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2933 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2934
2935 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2936
2937 if (dst_entries_init(&ipv4_dst_ops) < 0)
2938 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2939
2940 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2941 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2942
2943 ipv4_dst_ops.gc_thresh = ~0;
2944 ip_rt_max_size = INT_MAX;
2945
2946 devinet_init();
2947 ip_fib_init();
2948
2949 if (ip_rt_proc_init())
2950 pr_err("Unable to create route proc files\n");
2951 #ifdef CONFIG_XFRM
2952 xfrm_init();
2953 xfrm4_init();
2954 #endif
2955 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2956
2957 #ifdef CONFIG_SYSCTL
2958 register_pernet_subsys(&sysctl_route_ops);
2959 #endif
2960 register_pernet_subsys(&rt_genid_ops);
2961 register_pernet_subsys(&ipv4_inetpeer_ops);
2962 return rc;
2963 }
2964
2965 #ifdef CONFIG_SYSCTL
2966 /*
2967 * We really need to sanitize the damn ipv4 init order, then all
2968 * this nonsense will go away.
2969 */
2970 void __init ip_static_sysctl_init(void)
2971 {
2972 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2973 }
2974 #endif
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