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1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * ROUTE - implementation of the IP router.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox, <gw4pts@gw4pts.ampr.org>
11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
13 *
14 * Fixes:
15 * Alan Cox : Verify area fixes.
16 * Alan Cox : cli() protects routing changes
17 * Rui Oliveira : ICMP routing table updates
18 * (rco@di.uminho.pt) Routing table insertion and update
19 * Linus Torvalds : Rewrote bits to be sensible
20 * Alan Cox : Added BSD route gw semantics
21 * Alan Cox : Super /proc >4K
22 * Alan Cox : MTU in route table
23 * Alan Cox : MSS actually. Also added the window
24 * clamper.
25 * Sam Lantinga : Fixed route matching in rt_del()
26 * Alan Cox : Routing cache support.
27 * Alan Cox : Removed compatibility cruft.
28 * Alan Cox : RTF_REJECT support.
29 * Alan Cox : TCP irtt support.
30 * Jonathan Naylor : Added Metric support.
31 * Miquel van Smoorenburg : BSD API fixes.
32 * Miquel van Smoorenburg : Metrics.
33 * Alan Cox : Use __u32 properly
34 * Alan Cox : Aligned routing errors more closely with BSD
35 * our system is still very different.
36 * Alan Cox : Faster /proc handling
37 * Alexey Kuznetsov : Massive rework to support tree based routing,
38 * routing caches and better behaviour.
39 *
40 * Olaf Erb : irtt wasn't being copied right.
41 * Bjorn Ekwall : Kerneld route support.
42 * Alan Cox : Multicast fixed (I hope)
43 * Pavel Krauz : Limited broadcast fixed
44 * Mike McLagan : Routing by source
45 * Alexey Kuznetsov : End of old history. Split to fib.c and
46 * route.c and rewritten from scratch.
47 * Andi Kleen : Load-limit warning messages.
48 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
52 * Marc Boucher : routing by fwmark
53 * Robert Olsson : Added rt_cache statistics
54 * Arnaldo C. Melo : Convert proc stuff to seq_file
55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
57 * Ilia Sotnikov : Removed TOS from hash calculations
58 *
59 * This program is free software; you can redistribute it and/or
60 * modify it under the terms of the GNU General Public License
61 * as published by the Free Software Foundation; either version
62 * 2 of the License, or (at your option) any later version.
63 */
64
65 #define pr_fmt(fmt) "IPv4: " fmt
66
67 #include <linux/module.h>
68 #include <linux/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/types.h>
71 #include <linux/kernel.h>
72 #include <linux/mm.h>
73 #include <linux/string.h>
74 #include <linux/socket.h>
75 #include <linux/sockios.h>
76 #include <linux/errno.h>
77 #include <linux/in.h>
78 #include <linux/inet.h>
79 #include <linux/netdevice.h>
80 #include <linux/proc_fs.h>
81 #include <linux/init.h>
82 #include <linux/skbuff.h>
83 #include <linux/inetdevice.h>
84 #include <linux/igmp.h>
85 #include <linux/pkt_sched.h>
86 #include <linux/mroute.h>
87 #include <linux/netfilter_ipv4.h>
88 #include <linux/random.h>
89 #include <linux/rcupdate.h>
90 #include <linux/times.h>
91 #include <linux/slab.h>
92 #include <linux/jhash.h>
93 #include <net/dst.h>
94 #include <net/dst_metadata.h>
95 #include <net/net_namespace.h>
96 #include <net/protocol.h>
97 #include <net/ip.h>
98 #include <net/route.h>
99 #include <net/inetpeer.h>
100 #include <net/sock.h>
101 #include <net/ip_fib.h>
102 #include <net/arp.h>
103 #include <net/tcp.h>
104 #include <net/icmp.h>
105 #include <net/xfrm.h>
106 #include <net/lwtunnel.h>
107 #include <net/netevent.h>
108 #include <net/rtnetlink.h>
109 #ifdef CONFIG_SYSCTL
110 #include <linux/sysctl.h>
111 #include <linux/kmemleak.h>
112 #endif
113 #include <net/secure_seq.h>
114 #include <net/ip_tunnels.h>
115 #include <net/l3mdev.h>
116
117 #define RT_FL_TOS(oldflp4) \
118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
119
120 #define RT_GC_TIMEOUT (300*HZ)
121
122 static int ip_rt_max_size;
123 static int ip_rt_redirect_number __read_mostly = 9;
124 static int ip_rt_redirect_load __read_mostly = HZ / 50;
125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
126 static int ip_rt_error_cost __read_mostly = HZ;
127 static int ip_rt_error_burst __read_mostly = 5 * HZ;
128 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
129 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
130 static int ip_rt_min_advmss __read_mostly = 256;
131
132 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
133 /*
134 * Interface to generic destination cache.
135 */
136
137 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
138 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
139 static unsigned int ipv4_mtu(const struct dst_entry *dst);
140 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
141 static void ipv4_link_failure(struct sk_buff *skb);
142 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
143 struct sk_buff *skb, u32 mtu);
144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146 static void ipv4_dst_destroy(struct dst_entry *dst);
147
148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
149 {
150 WARN_ON(1);
151 return NULL;
152 }
153
154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
155 struct sk_buff *skb,
156 const void *daddr);
157 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
158
159 static struct dst_ops ipv4_dst_ops = {
160 .family = AF_INET,
161 .check = ipv4_dst_check,
162 .default_advmss = ipv4_default_advmss,
163 .mtu = ipv4_mtu,
164 .cow_metrics = ipv4_cow_metrics,
165 .destroy = ipv4_dst_destroy,
166 .negative_advice = ipv4_negative_advice,
167 .link_failure = ipv4_link_failure,
168 .update_pmtu = ip_rt_update_pmtu,
169 .redirect = ip_do_redirect,
170 .local_out = __ip_local_out,
171 .neigh_lookup = ipv4_neigh_lookup,
172 .confirm_neigh = ipv4_confirm_neigh,
173 };
174
175 #define ECN_OR_COST(class) TC_PRIO_##class
176
177 const __u8 ip_tos2prio[16] = {
178 TC_PRIO_BESTEFFORT,
179 ECN_OR_COST(BESTEFFORT),
180 TC_PRIO_BESTEFFORT,
181 ECN_OR_COST(BESTEFFORT),
182 TC_PRIO_BULK,
183 ECN_OR_COST(BULK),
184 TC_PRIO_BULK,
185 ECN_OR_COST(BULK),
186 TC_PRIO_INTERACTIVE,
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE,
189 ECN_OR_COST(INTERACTIVE),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK),
192 TC_PRIO_INTERACTIVE_BULK,
193 ECN_OR_COST(INTERACTIVE_BULK)
194 };
195 EXPORT_SYMBOL(ip_tos2prio);
196
197 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
198 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
199
200 #ifdef CONFIG_PROC_FS
201 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
202 {
203 if (*pos)
204 return NULL;
205 return SEQ_START_TOKEN;
206 }
207
208 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
209 {
210 ++*pos;
211 return NULL;
212 }
213
214 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
215 {
216 }
217
218 static int rt_cache_seq_show(struct seq_file *seq, void *v)
219 {
220 if (v == SEQ_START_TOKEN)
221 seq_printf(seq, "%-127s\n",
222 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
223 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
224 "HHUptod\tSpecDst");
225 return 0;
226 }
227
228 static const struct seq_operations rt_cache_seq_ops = {
229 .start = rt_cache_seq_start,
230 .next = rt_cache_seq_next,
231 .stop = rt_cache_seq_stop,
232 .show = rt_cache_seq_show,
233 };
234
235 static int rt_cache_seq_open(struct inode *inode, struct file *file)
236 {
237 return seq_open(file, &rt_cache_seq_ops);
238 }
239
240 static const struct file_operations rt_cache_seq_fops = {
241 .owner = THIS_MODULE,
242 .open = rt_cache_seq_open,
243 .read = seq_read,
244 .llseek = seq_lseek,
245 .release = seq_release,
246 };
247
248
249 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
250 {
251 int cpu;
252
253 if (*pos == 0)
254 return SEQ_START_TOKEN;
255
256 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
257 if (!cpu_possible(cpu))
258 continue;
259 *pos = cpu+1;
260 return &per_cpu(rt_cache_stat, cpu);
261 }
262 return NULL;
263 }
264
265 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
266 {
267 int cpu;
268
269 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
270 if (!cpu_possible(cpu))
271 continue;
272 *pos = cpu+1;
273 return &per_cpu(rt_cache_stat, cpu);
274 }
275 return NULL;
276
277 }
278
279 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
280 {
281
282 }
283
284 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
285 {
286 struct rt_cache_stat *st = v;
287
288 if (v == SEQ_START_TOKEN) {
289 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
290 return 0;
291 }
292
293 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
294 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
295 dst_entries_get_slow(&ipv4_dst_ops),
296 0, /* st->in_hit */
297 st->in_slow_tot,
298 st->in_slow_mc,
299 st->in_no_route,
300 st->in_brd,
301 st->in_martian_dst,
302 st->in_martian_src,
303
304 0, /* st->out_hit */
305 st->out_slow_tot,
306 st->out_slow_mc,
307
308 0, /* st->gc_total */
309 0, /* st->gc_ignored */
310 0, /* st->gc_goal_miss */
311 0, /* st->gc_dst_overflow */
312 0, /* st->in_hlist_search */
313 0 /* st->out_hlist_search */
314 );
315 return 0;
316 }
317
318 static const struct seq_operations rt_cpu_seq_ops = {
319 .start = rt_cpu_seq_start,
320 .next = rt_cpu_seq_next,
321 .stop = rt_cpu_seq_stop,
322 .show = rt_cpu_seq_show,
323 };
324
325
326 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
327 {
328 return seq_open(file, &rt_cpu_seq_ops);
329 }
330
331 static const struct file_operations rt_cpu_seq_fops = {
332 .owner = THIS_MODULE,
333 .open = rt_cpu_seq_open,
334 .read = seq_read,
335 .llseek = seq_lseek,
336 .release = seq_release,
337 };
338
339 #ifdef CONFIG_IP_ROUTE_CLASSID
340 static int rt_acct_proc_show(struct seq_file *m, void *v)
341 {
342 struct ip_rt_acct *dst, *src;
343 unsigned int i, j;
344
345 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
346 if (!dst)
347 return -ENOMEM;
348
349 for_each_possible_cpu(i) {
350 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
351 for (j = 0; j < 256; j++) {
352 dst[j].o_bytes += src[j].o_bytes;
353 dst[j].o_packets += src[j].o_packets;
354 dst[j].i_bytes += src[j].i_bytes;
355 dst[j].i_packets += src[j].i_packets;
356 }
357 }
358
359 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
360 kfree(dst);
361 return 0;
362 }
363
364 static int rt_acct_proc_open(struct inode *inode, struct file *file)
365 {
366 return single_open(file, rt_acct_proc_show, NULL);
367 }
368
369 static const struct file_operations rt_acct_proc_fops = {
370 .owner = THIS_MODULE,
371 .open = rt_acct_proc_open,
372 .read = seq_read,
373 .llseek = seq_lseek,
374 .release = single_release,
375 };
376 #endif
377
378 static int __net_init ip_rt_do_proc_init(struct net *net)
379 {
380 struct proc_dir_entry *pde;
381
382 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
383 &rt_cache_seq_fops);
384 if (!pde)
385 goto err1;
386
387 pde = proc_create("rt_cache", S_IRUGO,
388 net->proc_net_stat, &rt_cpu_seq_fops);
389 if (!pde)
390 goto err2;
391
392 #ifdef CONFIG_IP_ROUTE_CLASSID
393 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
394 if (!pde)
395 goto err3;
396 #endif
397 return 0;
398
399 #ifdef CONFIG_IP_ROUTE_CLASSID
400 err3:
401 remove_proc_entry("rt_cache", net->proc_net_stat);
402 #endif
403 err2:
404 remove_proc_entry("rt_cache", net->proc_net);
405 err1:
406 return -ENOMEM;
407 }
408
409 static void __net_exit ip_rt_do_proc_exit(struct net *net)
410 {
411 remove_proc_entry("rt_cache", net->proc_net_stat);
412 remove_proc_entry("rt_cache", net->proc_net);
413 #ifdef CONFIG_IP_ROUTE_CLASSID
414 remove_proc_entry("rt_acct", net->proc_net);
415 #endif
416 }
417
418 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
419 .init = ip_rt_do_proc_init,
420 .exit = ip_rt_do_proc_exit,
421 };
422
423 static int __init ip_rt_proc_init(void)
424 {
425 return register_pernet_subsys(&ip_rt_proc_ops);
426 }
427
428 #else
429 static inline int ip_rt_proc_init(void)
430 {
431 return 0;
432 }
433 #endif /* CONFIG_PROC_FS */
434
435 static inline bool rt_is_expired(const struct rtable *rth)
436 {
437 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
438 }
439
440 void rt_cache_flush(struct net *net)
441 {
442 rt_genid_bump_ipv4(net);
443 }
444
445 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
446 struct sk_buff *skb,
447 const void *daddr)
448 {
449 struct net_device *dev = dst->dev;
450 const __be32 *pkey = daddr;
451 const struct rtable *rt;
452 struct neighbour *n;
453
454 rt = (const struct rtable *) dst;
455 if (rt->rt_gateway)
456 pkey = (const __be32 *) &rt->rt_gateway;
457 else if (skb)
458 pkey = &ip_hdr(skb)->daddr;
459
460 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
461 if (n)
462 return n;
463 return neigh_create(&arp_tbl, pkey, dev);
464 }
465
466 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
467 {
468 struct net_device *dev = dst->dev;
469 const __be32 *pkey = daddr;
470 const struct rtable *rt;
471
472 rt = (const struct rtable *)dst;
473 if (rt->rt_gateway)
474 pkey = (const __be32 *)&rt->rt_gateway;
475 else if (!daddr ||
476 (rt->rt_flags &
477 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
478 return;
479
480 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
481 }
482
483 #define IP_IDENTS_SZ 2048u
484
485 static atomic_t *ip_idents __read_mostly;
486 static u32 *ip_tstamps __read_mostly;
487
488 /* In order to protect privacy, we add a perturbation to identifiers
489 * if one generator is seldom used. This makes hard for an attacker
490 * to infer how many packets were sent between two points in time.
491 */
492 u32 ip_idents_reserve(u32 hash, int segs)
493 {
494 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
495 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
496 u32 old = ACCESS_ONCE(*p_tstamp);
497 u32 now = (u32)jiffies;
498 u32 new, delta = 0;
499
500 if (old != now && cmpxchg(p_tstamp, old, now) == old)
501 delta = prandom_u32_max(now - old);
502
503 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
504 do {
505 old = (u32)atomic_read(p_id);
506 new = old + delta + segs;
507 } while (atomic_cmpxchg(p_id, old, new) != old);
508
509 return new - segs;
510 }
511 EXPORT_SYMBOL(ip_idents_reserve);
512
513 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
514 {
515 static u32 ip_idents_hashrnd __read_mostly;
516 u32 hash, id;
517
518 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
519
520 hash = jhash_3words((__force u32)iph->daddr,
521 (__force u32)iph->saddr,
522 iph->protocol ^ net_hash_mix(net),
523 ip_idents_hashrnd);
524 id = ip_idents_reserve(hash, segs);
525 iph->id = htons(id);
526 }
527 EXPORT_SYMBOL(__ip_select_ident);
528
529 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
530 const struct sock *sk,
531 const struct iphdr *iph,
532 int oif, u8 tos,
533 u8 prot, u32 mark, int flow_flags)
534 {
535 if (sk) {
536 const struct inet_sock *inet = inet_sk(sk);
537
538 oif = sk->sk_bound_dev_if;
539 mark = sk->sk_mark;
540 tos = RT_CONN_FLAGS(sk);
541 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
542 }
543 flowi4_init_output(fl4, oif, mark, tos,
544 RT_SCOPE_UNIVERSE, prot,
545 flow_flags,
546 iph->daddr, iph->saddr, 0, 0,
547 sock_net_uid(net, sk));
548 }
549
550 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
551 const struct sock *sk)
552 {
553 const struct net *net = dev_net(skb->dev);
554 const struct iphdr *iph = ip_hdr(skb);
555 int oif = skb->dev->ifindex;
556 u8 tos = RT_TOS(iph->tos);
557 u8 prot = iph->protocol;
558 u32 mark = skb->mark;
559
560 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
561 }
562
563 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
564 {
565 const struct inet_sock *inet = inet_sk(sk);
566 const struct ip_options_rcu *inet_opt;
567 __be32 daddr = inet->inet_daddr;
568
569 rcu_read_lock();
570 inet_opt = rcu_dereference(inet->inet_opt);
571 if (inet_opt && inet_opt->opt.srr)
572 daddr = inet_opt->opt.faddr;
573 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
574 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
575 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
576 inet_sk_flowi_flags(sk),
577 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
578 rcu_read_unlock();
579 }
580
581 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
582 const struct sk_buff *skb)
583 {
584 if (skb)
585 build_skb_flow_key(fl4, skb, sk);
586 else
587 build_sk_flow_key(fl4, sk);
588 }
589
590 static inline void rt_free(struct rtable *rt)
591 {
592 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
593 }
594
595 static DEFINE_SPINLOCK(fnhe_lock);
596
597 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
598 {
599 struct rtable *rt;
600
601 rt = rcu_dereference(fnhe->fnhe_rth_input);
602 if (rt) {
603 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
604 rt_free(rt);
605 }
606 rt = rcu_dereference(fnhe->fnhe_rth_output);
607 if (rt) {
608 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
609 rt_free(rt);
610 }
611 }
612
613 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
614 {
615 struct fib_nh_exception *fnhe, *oldest;
616
617 oldest = rcu_dereference(hash->chain);
618 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
619 fnhe = rcu_dereference(fnhe->fnhe_next)) {
620 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
621 oldest = fnhe;
622 }
623 fnhe_flush_routes(oldest);
624 return oldest;
625 }
626
627 static inline u32 fnhe_hashfun(__be32 daddr)
628 {
629 static u32 fnhe_hashrnd __read_mostly;
630 u32 hval;
631
632 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
633 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
634 return hash_32(hval, FNHE_HASH_SHIFT);
635 }
636
637 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
638 {
639 rt->rt_pmtu = fnhe->fnhe_pmtu;
640 rt->dst.expires = fnhe->fnhe_expires;
641
642 if (fnhe->fnhe_gw) {
643 rt->rt_flags |= RTCF_REDIRECTED;
644 rt->rt_gateway = fnhe->fnhe_gw;
645 rt->rt_uses_gateway = 1;
646 }
647 }
648
649 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
650 u32 pmtu, unsigned long expires)
651 {
652 struct fnhe_hash_bucket *hash;
653 struct fib_nh_exception *fnhe;
654 struct rtable *rt;
655 unsigned int i;
656 int depth;
657 u32 hval = fnhe_hashfun(daddr);
658
659 spin_lock_bh(&fnhe_lock);
660
661 hash = rcu_dereference(nh->nh_exceptions);
662 if (!hash) {
663 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
664 if (!hash)
665 goto out_unlock;
666 rcu_assign_pointer(nh->nh_exceptions, hash);
667 }
668
669 hash += hval;
670
671 depth = 0;
672 for (fnhe = rcu_dereference(hash->chain); fnhe;
673 fnhe = rcu_dereference(fnhe->fnhe_next)) {
674 if (fnhe->fnhe_daddr == daddr)
675 break;
676 depth++;
677 }
678
679 if (fnhe) {
680 if (gw)
681 fnhe->fnhe_gw = gw;
682 if (pmtu) {
683 fnhe->fnhe_pmtu = pmtu;
684 fnhe->fnhe_expires = max(1UL, expires);
685 }
686 /* Update all cached dsts too */
687 rt = rcu_dereference(fnhe->fnhe_rth_input);
688 if (rt)
689 fill_route_from_fnhe(rt, fnhe);
690 rt = rcu_dereference(fnhe->fnhe_rth_output);
691 if (rt)
692 fill_route_from_fnhe(rt, fnhe);
693 } else {
694 if (depth > FNHE_RECLAIM_DEPTH)
695 fnhe = fnhe_oldest(hash);
696 else {
697 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
698 if (!fnhe)
699 goto out_unlock;
700
701 fnhe->fnhe_next = hash->chain;
702 rcu_assign_pointer(hash->chain, fnhe);
703 }
704 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
705 fnhe->fnhe_daddr = daddr;
706 fnhe->fnhe_gw = gw;
707 fnhe->fnhe_pmtu = pmtu;
708 fnhe->fnhe_expires = expires;
709
710 /* Exception created; mark the cached routes for the nexthop
711 * stale, so anyone caching it rechecks if this exception
712 * applies to them.
713 */
714 rt = rcu_dereference(nh->nh_rth_input);
715 if (rt)
716 rt->dst.obsolete = DST_OBSOLETE_KILL;
717
718 for_each_possible_cpu(i) {
719 struct rtable __rcu **prt;
720 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
721 rt = rcu_dereference(*prt);
722 if (rt)
723 rt->dst.obsolete = DST_OBSOLETE_KILL;
724 }
725 }
726
727 fnhe->fnhe_stamp = jiffies;
728
729 out_unlock:
730 spin_unlock_bh(&fnhe_lock);
731 }
732
733 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
734 bool kill_route)
735 {
736 __be32 new_gw = icmp_hdr(skb)->un.gateway;
737 __be32 old_gw = ip_hdr(skb)->saddr;
738 struct net_device *dev = skb->dev;
739 struct in_device *in_dev;
740 struct fib_result res;
741 struct neighbour *n;
742 struct net *net;
743
744 switch (icmp_hdr(skb)->code & 7) {
745 case ICMP_REDIR_NET:
746 case ICMP_REDIR_NETTOS:
747 case ICMP_REDIR_HOST:
748 case ICMP_REDIR_HOSTTOS:
749 break;
750
751 default:
752 return;
753 }
754
755 if (rt->rt_gateway != old_gw)
756 return;
757
758 in_dev = __in_dev_get_rcu(dev);
759 if (!in_dev)
760 return;
761
762 net = dev_net(dev);
763 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
764 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
765 ipv4_is_zeronet(new_gw))
766 goto reject_redirect;
767
768 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
769 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
770 goto reject_redirect;
771 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
772 goto reject_redirect;
773 } else {
774 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
775 goto reject_redirect;
776 }
777
778 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
779 if (!n)
780 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
781 if (!IS_ERR(n)) {
782 if (!(n->nud_state & NUD_VALID)) {
783 neigh_event_send(n, NULL);
784 } else {
785 if (fib_lookup(net, fl4, &res, 0) == 0) {
786 struct fib_nh *nh = &FIB_RES_NH(res);
787
788 update_or_create_fnhe(nh, fl4->daddr, new_gw,
789 0, jiffies + ip_rt_gc_timeout);
790 }
791 if (kill_route)
792 rt->dst.obsolete = DST_OBSOLETE_KILL;
793 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
794 }
795 neigh_release(n);
796 }
797 return;
798
799 reject_redirect:
800 #ifdef CONFIG_IP_ROUTE_VERBOSE
801 if (IN_DEV_LOG_MARTIANS(in_dev)) {
802 const struct iphdr *iph = (const struct iphdr *) skb->data;
803 __be32 daddr = iph->daddr;
804 __be32 saddr = iph->saddr;
805
806 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
807 " Advised path = %pI4 -> %pI4\n",
808 &old_gw, dev->name, &new_gw,
809 &saddr, &daddr);
810 }
811 #endif
812 ;
813 }
814
815 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
816 {
817 struct rtable *rt;
818 struct flowi4 fl4;
819 const struct iphdr *iph = (const struct iphdr *) skb->data;
820 struct net *net = dev_net(skb->dev);
821 int oif = skb->dev->ifindex;
822 u8 tos = RT_TOS(iph->tos);
823 u8 prot = iph->protocol;
824 u32 mark = skb->mark;
825
826 rt = (struct rtable *) dst;
827
828 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
829 __ip_do_redirect(rt, skb, &fl4, true);
830 }
831
832 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
833 {
834 struct rtable *rt = (struct rtable *)dst;
835 struct dst_entry *ret = dst;
836
837 if (rt) {
838 if (dst->obsolete > 0) {
839 ip_rt_put(rt);
840 ret = NULL;
841 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
842 rt->dst.expires) {
843 ip_rt_put(rt);
844 ret = NULL;
845 }
846 }
847 return ret;
848 }
849
850 /*
851 * Algorithm:
852 * 1. The first ip_rt_redirect_number redirects are sent
853 * with exponential backoff, then we stop sending them at all,
854 * assuming that the host ignores our redirects.
855 * 2. If we did not see packets requiring redirects
856 * during ip_rt_redirect_silence, we assume that the host
857 * forgot redirected route and start to send redirects again.
858 *
859 * This algorithm is much cheaper and more intelligent than dumb load limiting
860 * in icmp.c.
861 *
862 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
863 * and "frag. need" (breaks PMTU discovery) in icmp.c.
864 */
865
866 void ip_rt_send_redirect(struct sk_buff *skb)
867 {
868 struct rtable *rt = skb_rtable(skb);
869 struct in_device *in_dev;
870 struct inet_peer *peer;
871 struct net *net;
872 int log_martians;
873 int vif;
874
875 rcu_read_lock();
876 in_dev = __in_dev_get_rcu(rt->dst.dev);
877 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
878 rcu_read_unlock();
879 return;
880 }
881 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
882 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
883 rcu_read_unlock();
884
885 net = dev_net(rt->dst.dev);
886 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
887 if (!peer) {
888 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
889 rt_nexthop(rt, ip_hdr(skb)->daddr));
890 return;
891 }
892
893 /* No redirected packets during ip_rt_redirect_silence;
894 * reset the algorithm.
895 */
896 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
897 peer->rate_tokens = 0;
898
899 /* Too many ignored redirects; do not send anything
900 * set dst.rate_last to the last seen redirected packet.
901 */
902 if (peer->rate_tokens >= ip_rt_redirect_number) {
903 peer->rate_last = jiffies;
904 goto out_put_peer;
905 }
906
907 /* Check for load limit; set rate_last to the latest sent
908 * redirect.
909 */
910 if (peer->rate_tokens == 0 ||
911 time_after(jiffies,
912 (peer->rate_last +
913 (ip_rt_redirect_load << peer->rate_tokens)))) {
914 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
915
916 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
917 peer->rate_last = jiffies;
918 ++peer->rate_tokens;
919 #ifdef CONFIG_IP_ROUTE_VERBOSE
920 if (log_martians &&
921 peer->rate_tokens == ip_rt_redirect_number)
922 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
923 &ip_hdr(skb)->saddr, inet_iif(skb),
924 &ip_hdr(skb)->daddr, &gw);
925 #endif
926 }
927 out_put_peer:
928 inet_putpeer(peer);
929 }
930
931 static int ip_error(struct sk_buff *skb)
932 {
933 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
934 struct rtable *rt = skb_rtable(skb);
935 struct inet_peer *peer;
936 unsigned long now;
937 struct net *net;
938 bool send;
939 int code;
940
941 /* IP on this device is disabled. */
942 if (!in_dev)
943 goto out;
944
945 net = dev_net(rt->dst.dev);
946 if (!IN_DEV_FORWARD(in_dev)) {
947 switch (rt->dst.error) {
948 case EHOSTUNREACH:
949 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
950 break;
951
952 case ENETUNREACH:
953 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
954 break;
955 }
956 goto out;
957 }
958
959 switch (rt->dst.error) {
960 case EINVAL:
961 default:
962 goto out;
963 case EHOSTUNREACH:
964 code = ICMP_HOST_UNREACH;
965 break;
966 case ENETUNREACH:
967 code = ICMP_NET_UNREACH;
968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
969 break;
970 case EACCES:
971 code = ICMP_PKT_FILTERED;
972 break;
973 }
974
975 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
976 l3mdev_master_ifindex(skb->dev), 1);
977
978 send = true;
979 if (peer) {
980 now = jiffies;
981 peer->rate_tokens += now - peer->rate_last;
982 if (peer->rate_tokens > ip_rt_error_burst)
983 peer->rate_tokens = ip_rt_error_burst;
984 peer->rate_last = now;
985 if (peer->rate_tokens >= ip_rt_error_cost)
986 peer->rate_tokens -= ip_rt_error_cost;
987 else
988 send = false;
989 inet_putpeer(peer);
990 }
991 if (send)
992 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
993
994 out: kfree_skb(skb);
995 return 0;
996 }
997
998 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
999 {
1000 struct dst_entry *dst = &rt->dst;
1001 struct fib_result res;
1002
1003 if (dst_metric_locked(dst, RTAX_MTU))
1004 return;
1005
1006 if (ipv4_mtu(dst) < mtu)
1007 return;
1008
1009 if (mtu < ip_rt_min_pmtu)
1010 mtu = ip_rt_min_pmtu;
1011
1012 if (rt->rt_pmtu == mtu &&
1013 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1014 return;
1015
1016 rcu_read_lock();
1017 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1018 struct fib_nh *nh = &FIB_RES_NH(res);
1019
1020 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
1021 jiffies + ip_rt_mtu_expires);
1022 }
1023 rcu_read_unlock();
1024 }
1025
1026 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1027 struct sk_buff *skb, u32 mtu)
1028 {
1029 struct rtable *rt = (struct rtable *) dst;
1030 struct flowi4 fl4;
1031
1032 ip_rt_build_flow_key(&fl4, sk, skb);
1033 __ip_rt_update_pmtu(rt, &fl4, mtu);
1034 }
1035
1036 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1037 int oif, u32 mark, u8 protocol, int flow_flags)
1038 {
1039 const struct iphdr *iph = (const struct iphdr *) skb->data;
1040 struct flowi4 fl4;
1041 struct rtable *rt;
1042
1043 if (!mark)
1044 mark = IP4_REPLY_MARK(net, skb->mark);
1045
1046 __build_flow_key(net, &fl4, NULL, iph, oif,
1047 RT_TOS(iph->tos), protocol, mark, flow_flags);
1048 rt = __ip_route_output_key(net, &fl4);
1049 if (!IS_ERR(rt)) {
1050 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 ip_rt_put(rt);
1052 }
1053 }
1054 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1055
1056 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1057 {
1058 const struct iphdr *iph = (const struct iphdr *) skb->data;
1059 struct flowi4 fl4;
1060 struct rtable *rt;
1061
1062 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1063
1064 if (!fl4.flowi4_mark)
1065 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1066
1067 rt = __ip_route_output_key(sock_net(sk), &fl4);
1068 if (!IS_ERR(rt)) {
1069 __ip_rt_update_pmtu(rt, &fl4, mtu);
1070 ip_rt_put(rt);
1071 }
1072 }
1073
1074 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1075 {
1076 const struct iphdr *iph = (const struct iphdr *) skb->data;
1077 struct flowi4 fl4;
1078 struct rtable *rt;
1079 struct dst_entry *odst = NULL;
1080 bool new = false;
1081 struct net *net = sock_net(sk);
1082
1083 bh_lock_sock(sk);
1084
1085 if (!ip_sk_accept_pmtu(sk))
1086 goto out;
1087
1088 odst = sk_dst_get(sk);
1089
1090 if (sock_owned_by_user(sk) || !odst) {
1091 __ipv4_sk_update_pmtu(skb, sk, mtu);
1092 goto out;
1093 }
1094
1095 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1096
1097 rt = (struct rtable *)odst;
1098 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1099 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1100 if (IS_ERR(rt))
1101 goto out;
1102
1103 new = true;
1104 }
1105
1106 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1107
1108 if (!dst_check(&rt->dst, 0)) {
1109 if (new)
1110 dst_release(&rt->dst);
1111
1112 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1113 if (IS_ERR(rt))
1114 goto out;
1115
1116 new = true;
1117 }
1118
1119 if (new)
1120 sk_dst_set(sk, &rt->dst);
1121
1122 out:
1123 bh_unlock_sock(sk);
1124 dst_release(odst);
1125 }
1126 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1127
1128 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1129 int oif, u32 mark, u8 protocol, int flow_flags)
1130 {
1131 const struct iphdr *iph = (const struct iphdr *) skb->data;
1132 struct flowi4 fl4;
1133 struct rtable *rt;
1134
1135 __build_flow_key(net, &fl4, NULL, iph, oif,
1136 RT_TOS(iph->tos), protocol, mark, flow_flags);
1137 rt = __ip_route_output_key(net, &fl4);
1138 if (!IS_ERR(rt)) {
1139 __ip_do_redirect(rt, skb, &fl4, false);
1140 ip_rt_put(rt);
1141 }
1142 }
1143 EXPORT_SYMBOL_GPL(ipv4_redirect);
1144
1145 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1146 {
1147 const struct iphdr *iph = (const struct iphdr *) skb->data;
1148 struct flowi4 fl4;
1149 struct rtable *rt;
1150 struct net *net = sock_net(sk);
1151
1152 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1153 rt = __ip_route_output_key(net, &fl4);
1154 if (!IS_ERR(rt)) {
1155 __ip_do_redirect(rt, skb, &fl4, false);
1156 ip_rt_put(rt);
1157 }
1158 }
1159 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1160
1161 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1162 {
1163 struct rtable *rt = (struct rtable *) dst;
1164
1165 /* All IPV4 dsts are created with ->obsolete set to the value
1166 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1167 * into this function always.
1168 *
1169 * When a PMTU/redirect information update invalidates a route,
1170 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1171 * DST_OBSOLETE_DEAD by dst_free().
1172 */
1173 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1174 return NULL;
1175 return dst;
1176 }
1177
1178 static void ipv4_link_failure(struct sk_buff *skb)
1179 {
1180 struct rtable *rt;
1181
1182 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1183
1184 rt = skb_rtable(skb);
1185 if (rt)
1186 dst_set_expires(&rt->dst, 0);
1187 }
1188
1189 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1190 {
1191 pr_debug("%s: %pI4 -> %pI4, %s\n",
1192 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1193 skb->dev ? skb->dev->name : "?");
1194 kfree_skb(skb);
1195 WARN_ON(1);
1196 return 0;
1197 }
1198
1199 /*
1200 We do not cache source address of outgoing interface,
1201 because it is used only by IP RR, TS and SRR options,
1202 so that it out of fast path.
1203
1204 BTW remember: "addr" is allowed to be not aligned
1205 in IP options!
1206 */
1207
1208 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1209 {
1210 __be32 src;
1211
1212 if (rt_is_output_route(rt))
1213 src = ip_hdr(skb)->saddr;
1214 else {
1215 struct fib_result res;
1216 struct flowi4 fl4;
1217 struct iphdr *iph;
1218
1219 iph = ip_hdr(skb);
1220
1221 memset(&fl4, 0, sizeof(fl4));
1222 fl4.daddr = iph->daddr;
1223 fl4.saddr = iph->saddr;
1224 fl4.flowi4_tos = RT_TOS(iph->tos);
1225 fl4.flowi4_oif = rt->dst.dev->ifindex;
1226 fl4.flowi4_iif = skb->dev->ifindex;
1227 fl4.flowi4_mark = skb->mark;
1228
1229 rcu_read_lock();
1230 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1231 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1232 else
1233 src = inet_select_addr(rt->dst.dev,
1234 rt_nexthop(rt, iph->daddr),
1235 RT_SCOPE_UNIVERSE);
1236 rcu_read_unlock();
1237 }
1238 memcpy(addr, &src, 4);
1239 }
1240
1241 #ifdef CONFIG_IP_ROUTE_CLASSID
1242 static void set_class_tag(struct rtable *rt, u32 tag)
1243 {
1244 if (!(rt->dst.tclassid & 0xFFFF))
1245 rt->dst.tclassid |= tag & 0xFFFF;
1246 if (!(rt->dst.tclassid & 0xFFFF0000))
1247 rt->dst.tclassid |= tag & 0xFFFF0000;
1248 }
1249 #endif
1250
1251 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1252 {
1253 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1254
1255 if (advmss == 0) {
1256 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1257 ip_rt_min_advmss);
1258 if (advmss > 65535 - 40)
1259 advmss = 65535 - 40;
1260 }
1261 return advmss;
1262 }
1263
1264 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1265 {
1266 const struct rtable *rt = (const struct rtable *) dst;
1267 unsigned int mtu = rt->rt_pmtu;
1268
1269 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1270 mtu = dst_metric_raw(dst, RTAX_MTU);
1271
1272 if (mtu)
1273 return mtu;
1274
1275 mtu = dst->dev->mtu;
1276
1277 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1278 if (rt->rt_uses_gateway && mtu > 576)
1279 mtu = 576;
1280 }
1281
1282 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1283
1284 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1285 }
1286
1287 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1288 {
1289 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1290 struct fib_nh_exception *fnhe;
1291 u32 hval;
1292
1293 if (!hash)
1294 return NULL;
1295
1296 hval = fnhe_hashfun(daddr);
1297
1298 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1299 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1300 if (fnhe->fnhe_daddr == daddr)
1301 return fnhe;
1302 }
1303 return NULL;
1304 }
1305
1306 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1307 __be32 daddr)
1308 {
1309 bool ret = false;
1310
1311 spin_lock_bh(&fnhe_lock);
1312
1313 if (daddr == fnhe->fnhe_daddr) {
1314 struct rtable __rcu **porig;
1315 struct rtable *orig;
1316 int genid = fnhe_genid(dev_net(rt->dst.dev));
1317
1318 if (rt_is_input_route(rt))
1319 porig = &fnhe->fnhe_rth_input;
1320 else
1321 porig = &fnhe->fnhe_rth_output;
1322 orig = rcu_dereference(*porig);
1323
1324 if (fnhe->fnhe_genid != genid) {
1325 fnhe->fnhe_genid = genid;
1326 fnhe->fnhe_gw = 0;
1327 fnhe->fnhe_pmtu = 0;
1328 fnhe->fnhe_expires = 0;
1329 fnhe_flush_routes(fnhe);
1330 orig = NULL;
1331 }
1332 fill_route_from_fnhe(rt, fnhe);
1333 if (!rt->rt_gateway)
1334 rt->rt_gateway = daddr;
1335
1336 if (!(rt->dst.flags & DST_NOCACHE)) {
1337 rcu_assign_pointer(*porig, rt);
1338 if (orig)
1339 rt_free(orig);
1340 ret = true;
1341 }
1342
1343 fnhe->fnhe_stamp = jiffies;
1344 }
1345 spin_unlock_bh(&fnhe_lock);
1346
1347 return ret;
1348 }
1349
1350 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1351 {
1352 struct rtable *orig, *prev, **p;
1353 bool ret = true;
1354
1355 if (rt_is_input_route(rt)) {
1356 p = (struct rtable **)&nh->nh_rth_input;
1357 } else {
1358 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1359 }
1360 orig = *p;
1361
1362 prev = cmpxchg(p, orig, rt);
1363 if (prev == orig) {
1364 if (orig)
1365 rt_free(orig);
1366 } else
1367 ret = false;
1368
1369 return ret;
1370 }
1371
1372 struct uncached_list {
1373 spinlock_t lock;
1374 struct list_head head;
1375 };
1376
1377 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1378
1379 static void rt_add_uncached_list(struct rtable *rt)
1380 {
1381 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1382
1383 rt->rt_uncached_list = ul;
1384
1385 spin_lock_bh(&ul->lock);
1386 list_add_tail(&rt->rt_uncached, &ul->head);
1387 spin_unlock_bh(&ul->lock);
1388 }
1389
1390 static void ipv4_dst_destroy(struct dst_entry *dst)
1391 {
1392 struct rtable *rt = (struct rtable *) dst;
1393
1394 if (!list_empty(&rt->rt_uncached)) {
1395 struct uncached_list *ul = rt->rt_uncached_list;
1396
1397 spin_lock_bh(&ul->lock);
1398 list_del(&rt->rt_uncached);
1399 spin_unlock_bh(&ul->lock);
1400 }
1401 }
1402
1403 void rt_flush_dev(struct net_device *dev)
1404 {
1405 struct net *net = dev_net(dev);
1406 struct rtable *rt;
1407 int cpu;
1408
1409 for_each_possible_cpu(cpu) {
1410 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1411
1412 spin_lock_bh(&ul->lock);
1413 list_for_each_entry(rt, &ul->head, rt_uncached) {
1414 if (rt->dst.dev != dev)
1415 continue;
1416 rt->dst.dev = net->loopback_dev;
1417 dev_hold(rt->dst.dev);
1418 dev_put(dev);
1419 }
1420 spin_unlock_bh(&ul->lock);
1421 }
1422 }
1423
1424 static bool rt_cache_valid(const struct rtable *rt)
1425 {
1426 return rt &&
1427 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1428 !rt_is_expired(rt);
1429 }
1430
1431 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1432 const struct fib_result *res,
1433 struct fib_nh_exception *fnhe,
1434 struct fib_info *fi, u16 type, u32 itag)
1435 {
1436 bool cached = false;
1437
1438 if (fi) {
1439 struct fib_nh *nh = &FIB_RES_NH(*res);
1440
1441 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1442 rt->rt_gateway = nh->nh_gw;
1443 rt->rt_uses_gateway = 1;
1444 }
1445 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1446 #ifdef CONFIG_IP_ROUTE_CLASSID
1447 rt->dst.tclassid = nh->nh_tclassid;
1448 #endif
1449 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1450 if (unlikely(fnhe))
1451 cached = rt_bind_exception(rt, fnhe, daddr);
1452 else if (!(rt->dst.flags & DST_NOCACHE))
1453 cached = rt_cache_route(nh, rt);
1454 if (unlikely(!cached)) {
1455 /* Routes we intend to cache in nexthop exception or
1456 * FIB nexthop have the DST_NOCACHE bit clear.
1457 * However, if we are unsuccessful at storing this
1458 * route into the cache we really need to set it.
1459 */
1460 rt->dst.flags |= DST_NOCACHE;
1461 if (!rt->rt_gateway)
1462 rt->rt_gateway = daddr;
1463 rt_add_uncached_list(rt);
1464 }
1465 } else
1466 rt_add_uncached_list(rt);
1467
1468 #ifdef CONFIG_IP_ROUTE_CLASSID
1469 #ifdef CONFIG_IP_MULTIPLE_TABLES
1470 set_class_tag(rt, res->tclassid);
1471 #endif
1472 set_class_tag(rt, itag);
1473 #endif
1474 }
1475
1476 struct rtable *rt_dst_alloc(struct net_device *dev,
1477 unsigned int flags, u16 type,
1478 bool nopolicy, bool noxfrm, bool will_cache)
1479 {
1480 struct rtable *rt;
1481
1482 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1483 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1484 (nopolicy ? DST_NOPOLICY : 0) |
1485 (noxfrm ? DST_NOXFRM : 0));
1486
1487 if (rt) {
1488 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1489 rt->rt_flags = flags;
1490 rt->rt_type = type;
1491 rt->rt_is_input = 0;
1492 rt->rt_iif = 0;
1493 rt->rt_pmtu = 0;
1494 rt->rt_gateway = 0;
1495 rt->rt_uses_gateway = 0;
1496 rt->rt_table_id = 0;
1497 INIT_LIST_HEAD(&rt->rt_uncached);
1498
1499 rt->dst.output = ip_output;
1500 if (flags & RTCF_LOCAL)
1501 rt->dst.input = ip_local_deliver;
1502 }
1503
1504 return rt;
1505 }
1506 EXPORT_SYMBOL(rt_dst_alloc);
1507
1508 /* called in rcu_read_lock() section */
1509 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1510 u8 tos, struct net_device *dev, int our)
1511 {
1512 struct rtable *rth;
1513 struct in_device *in_dev = __in_dev_get_rcu(dev);
1514 unsigned int flags = RTCF_MULTICAST;
1515 u32 itag = 0;
1516 int err;
1517
1518 /* Primary sanity checks. */
1519
1520 if (!in_dev)
1521 return -EINVAL;
1522
1523 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1524 skb->protocol != htons(ETH_P_IP))
1525 goto e_inval;
1526
1527 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1528 goto e_inval;
1529
1530 if (ipv4_is_zeronet(saddr)) {
1531 if (!ipv4_is_local_multicast(daddr))
1532 goto e_inval;
1533 } else {
1534 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1535 in_dev, &itag);
1536 if (err < 0)
1537 goto e_err;
1538 }
1539 if (our)
1540 flags |= RTCF_LOCAL;
1541
1542 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1543 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1544 if (!rth)
1545 goto e_nobufs;
1546
1547 #ifdef CONFIG_IP_ROUTE_CLASSID
1548 rth->dst.tclassid = itag;
1549 #endif
1550 rth->dst.output = ip_rt_bug;
1551 rth->rt_is_input= 1;
1552
1553 #ifdef CONFIG_IP_MROUTE
1554 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1555 rth->dst.input = ip_mr_input;
1556 #endif
1557 RT_CACHE_STAT_INC(in_slow_mc);
1558
1559 skb_dst_set(skb, &rth->dst);
1560 return 0;
1561
1562 e_nobufs:
1563 return -ENOBUFS;
1564 e_inval:
1565 return -EINVAL;
1566 e_err:
1567 return err;
1568 }
1569
1570
1571 static void ip_handle_martian_source(struct net_device *dev,
1572 struct in_device *in_dev,
1573 struct sk_buff *skb,
1574 __be32 daddr,
1575 __be32 saddr)
1576 {
1577 RT_CACHE_STAT_INC(in_martian_src);
1578 #ifdef CONFIG_IP_ROUTE_VERBOSE
1579 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1580 /*
1581 * RFC1812 recommendation, if source is martian,
1582 * the only hint is MAC header.
1583 */
1584 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1585 &daddr, &saddr, dev->name);
1586 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1587 print_hex_dump(KERN_WARNING, "ll header: ",
1588 DUMP_PREFIX_OFFSET, 16, 1,
1589 skb_mac_header(skb),
1590 dev->hard_header_len, true);
1591 }
1592 }
1593 #endif
1594 }
1595
1596 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1597 {
1598 struct fnhe_hash_bucket *hash;
1599 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1600 u32 hval = fnhe_hashfun(daddr);
1601
1602 spin_lock_bh(&fnhe_lock);
1603
1604 hash = rcu_dereference_protected(nh->nh_exceptions,
1605 lockdep_is_held(&fnhe_lock));
1606 hash += hval;
1607
1608 fnhe_p = &hash->chain;
1609 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1610 while (fnhe) {
1611 if (fnhe->fnhe_daddr == daddr) {
1612 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1613 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1614 fnhe_flush_routes(fnhe);
1615 kfree_rcu(fnhe, rcu);
1616 break;
1617 }
1618 fnhe_p = &fnhe->fnhe_next;
1619 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1620 lockdep_is_held(&fnhe_lock));
1621 }
1622
1623 spin_unlock_bh(&fnhe_lock);
1624 }
1625
1626 static void set_lwt_redirect(struct rtable *rth)
1627 {
1628 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1629 rth->dst.lwtstate->orig_output = rth->dst.output;
1630 rth->dst.output = lwtunnel_output;
1631 }
1632
1633 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1634 rth->dst.lwtstate->orig_input = rth->dst.input;
1635 rth->dst.input = lwtunnel_input;
1636 }
1637 }
1638
1639 /* called in rcu_read_lock() section */
1640 static int __mkroute_input(struct sk_buff *skb,
1641 const struct fib_result *res,
1642 struct in_device *in_dev,
1643 __be32 daddr, __be32 saddr, u32 tos)
1644 {
1645 struct fib_nh_exception *fnhe;
1646 struct rtable *rth;
1647 int err;
1648 struct in_device *out_dev;
1649 bool do_cache;
1650 u32 itag = 0;
1651
1652 /* get a working reference to the output device */
1653 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1654 if (!out_dev) {
1655 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1656 return -EINVAL;
1657 }
1658
1659 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1660 in_dev->dev, in_dev, &itag);
1661 if (err < 0) {
1662 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1663 saddr);
1664
1665 goto cleanup;
1666 }
1667
1668 do_cache = res->fi && !itag;
1669 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1670 skb->protocol == htons(ETH_P_IP) &&
1671 (IN_DEV_SHARED_MEDIA(out_dev) ||
1672 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1673 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1674
1675 if (skb->protocol != htons(ETH_P_IP)) {
1676 /* Not IP (i.e. ARP). Do not create route, if it is
1677 * invalid for proxy arp. DNAT routes are always valid.
1678 *
1679 * Proxy arp feature have been extended to allow, ARP
1680 * replies back to the same interface, to support
1681 * Private VLAN switch technologies. See arp.c.
1682 */
1683 if (out_dev == in_dev &&
1684 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1685 err = -EINVAL;
1686 goto cleanup;
1687 }
1688 }
1689
1690 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1691 if (do_cache) {
1692 if (fnhe) {
1693 rth = rcu_dereference(fnhe->fnhe_rth_input);
1694 if (rth && rth->dst.expires &&
1695 time_after(jiffies, rth->dst.expires)) {
1696 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1697 fnhe = NULL;
1698 } else {
1699 goto rt_cache;
1700 }
1701 }
1702
1703 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1704
1705 rt_cache:
1706 if (rt_cache_valid(rth)) {
1707 skb_dst_set_noref(skb, &rth->dst);
1708 goto out;
1709 }
1710 }
1711
1712 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1713 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1714 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1715 if (!rth) {
1716 err = -ENOBUFS;
1717 goto cleanup;
1718 }
1719
1720 rth->rt_is_input = 1;
1721 if (res->table)
1722 rth->rt_table_id = res->table->tb_id;
1723 RT_CACHE_STAT_INC(in_slow_tot);
1724
1725 rth->dst.input = ip_forward;
1726
1727 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1728 set_lwt_redirect(rth);
1729 skb_dst_set(skb, &rth->dst);
1730 out:
1731 err = 0;
1732 cleanup:
1733 return err;
1734 }
1735
1736 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1737
1738 /* To make ICMP packets follow the right flow, the multipath hash is
1739 * calculated from the inner IP addresses in reverse order.
1740 */
1741 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1742 {
1743 const struct iphdr *outer_iph = ip_hdr(skb);
1744 struct icmphdr _icmph;
1745 const struct icmphdr *icmph;
1746 struct iphdr _inner_iph;
1747 const struct iphdr *inner_iph;
1748
1749 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1750 goto standard_hash;
1751
1752 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1753 &_icmph);
1754 if (!icmph)
1755 goto standard_hash;
1756
1757 if (icmph->type != ICMP_DEST_UNREACH &&
1758 icmph->type != ICMP_REDIRECT &&
1759 icmph->type != ICMP_TIME_EXCEEDED &&
1760 icmph->type != ICMP_PARAMETERPROB) {
1761 goto standard_hash;
1762 }
1763
1764 inner_iph = skb_header_pointer(skb,
1765 outer_iph->ihl * 4 + sizeof(_icmph),
1766 sizeof(_inner_iph), &_inner_iph);
1767 if (!inner_iph)
1768 goto standard_hash;
1769
1770 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1771
1772 standard_hash:
1773 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1774 }
1775
1776 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1777
1778 static int ip_mkroute_input(struct sk_buff *skb,
1779 struct fib_result *res,
1780 struct in_device *in_dev,
1781 __be32 daddr, __be32 saddr, u32 tos)
1782 {
1783 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1784 if (res->fi && res->fi->fib_nhs > 1) {
1785 int h;
1786
1787 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1788 h = ip_multipath_icmp_hash(skb);
1789 else
1790 h = fib_multipath_hash(saddr, daddr);
1791 fib_select_multipath(res, h);
1792 }
1793 #endif
1794
1795 /* create a routing cache entry */
1796 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1797 }
1798
1799 /*
1800 * NOTE. We drop all the packets that has local source
1801 * addresses, because every properly looped back packet
1802 * must have correct destination already attached by output routine.
1803 *
1804 * Such approach solves two big problems:
1805 * 1. Not simplex devices are handled properly.
1806 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1807 * called with rcu_read_lock()
1808 */
1809
1810 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1811 u8 tos, struct net_device *dev)
1812 {
1813 struct fib_result res;
1814 struct in_device *in_dev = __in_dev_get_rcu(dev);
1815 struct ip_tunnel_info *tun_info;
1816 struct flowi4 fl4;
1817 unsigned int flags = 0;
1818 u32 itag = 0;
1819 struct rtable *rth;
1820 int err = -EINVAL;
1821 struct net *net = dev_net(dev);
1822 bool do_cache;
1823
1824 /* IP on this device is disabled. */
1825
1826 if (!in_dev)
1827 goto out;
1828
1829 /* Check for the most weird martians, which can be not detected
1830 by fib_lookup.
1831 */
1832
1833 tun_info = skb_tunnel_info(skb);
1834 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1835 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1836 else
1837 fl4.flowi4_tun_key.tun_id = 0;
1838 skb_dst_drop(skb);
1839
1840 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1841 goto martian_source;
1842
1843 res.fi = NULL;
1844 res.table = NULL;
1845 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1846 goto brd_input;
1847
1848 /* Accept zero addresses only to limited broadcast;
1849 * I even do not know to fix it or not. Waiting for complains :-)
1850 */
1851 if (ipv4_is_zeronet(saddr))
1852 goto martian_source;
1853
1854 if (ipv4_is_zeronet(daddr))
1855 goto martian_destination;
1856
1857 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1858 * and call it once if daddr or/and saddr are loopback addresses
1859 */
1860 if (ipv4_is_loopback(daddr)) {
1861 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1862 goto martian_destination;
1863 } else if (ipv4_is_loopback(saddr)) {
1864 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1865 goto martian_source;
1866 }
1867
1868 /*
1869 * Now we are ready to route packet.
1870 */
1871 fl4.flowi4_oif = 0;
1872 fl4.flowi4_iif = dev->ifindex;
1873 fl4.flowi4_mark = skb->mark;
1874 fl4.flowi4_tos = tos;
1875 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1876 fl4.flowi4_flags = 0;
1877 fl4.daddr = daddr;
1878 fl4.saddr = saddr;
1879 err = fib_lookup(net, &fl4, &res, 0);
1880 if (err != 0) {
1881 if (!IN_DEV_FORWARD(in_dev))
1882 err = -EHOSTUNREACH;
1883 goto no_route;
1884 }
1885
1886 if (res.type == RTN_BROADCAST)
1887 goto brd_input;
1888
1889 if (res.type == RTN_LOCAL) {
1890 err = fib_validate_source(skb, saddr, daddr, tos,
1891 0, dev, in_dev, &itag);
1892 if (err < 0)
1893 goto martian_source;
1894 goto local_input;
1895 }
1896
1897 if (!IN_DEV_FORWARD(in_dev)) {
1898 err = -EHOSTUNREACH;
1899 goto no_route;
1900 }
1901 if (res.type != RTN_UNICAST)
1902 goto martian_destination;
1903
1904 err = ip_mkroute_input(skb, &res, in_dev, daddr, saddr, tos);
1905 out: return err;
1906
1907 brd_input:
1908 if (skb->protocol != htons(ETH_P_IP))
1909 goto e_inval;
1910
1911 if (!ipv4_is_zeronet(saddr)) {
1912 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1913 in_dev, &itag);
1914 if (err < 0)
1915 goto martian_source;
1916 }
1917 flags |= RTCF_BROADCAST;
1918 res.type = RTN_BROADCAST;
1919 RT_CACHE_STAT_INC(in_brd);
1920
1921 local_input:
1922 do_cache = false;
1923 if (res.fi) {
1924 if (!itag) {
1925 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1926 if (rt_cache_valid(rth)) {
1927 skb_dst_set_noref(skb, &rth->dst);
1928 err = 0;
1929 goto out;
1930 }
1931 do_cache = true;
1932 }
1933 }
1934
1935 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
1936 flags | RTCF_LOCAL, res.type,
1937 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1938 if (!rth)
1939 goto e_nobufs;
1940
1941 rth->dst.output= ip_rt_bug;
1942 #ifdef CONFIG_IP_ROUTE_CLASSID
1943 rth->dst.tclassid = itag;
1944 #endif
1945 rth->rt_is_input = 1;
1946 if (res.table)
1947 rth->rt_table_id = res.table->tb_id;
1948
1949 RT_CACHE_STAT_INC(in_slow_tot);
1950 if (res.type == RTN_UNREACHABLE) {
1951 rth->dst.input= ip_error;
1952 rth->dst.error= -err;
1953 rth->rt_flags &= ~RTCF_LOCAL;
1954 }
1955
1956 if (do_cache) {
1957 struct fib_nh *nh = &FIB_RES_NH(res);
1958
1959 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1960 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1961 WARN_ON(rth->dst.input == lwtunnel_input);
1962 rth->dst.lwtstate->orig_input = rth->dst.input;
1963 rth->dst.input = lwtunnel_input;
1964 }
1965
1966 if (unlikely(!rt_cache_route(nh, rth))) {
1967 rth->dst.flags |= DST_NOCACHE;
1968 rt_add_uncached_list(rth);
1969 }
1970 }
1971 skb_dst_set(skb, &rth->dst);
1972 err = 0;
1973 goto out;
1974
1975 no_route:
1976 RT_CACHE_STAT_INC(in_no_route);
1977 res.type = RTN_UNREACHABLE;
1978 res.fi = NULL;
1979 res.table = NULL;
1980 goto local_input;
1981
1982 /*
1983 * Do not cache martian addresses: they should be logged (RFC1812)
1984 */
1985 martian_destination:
1986 RT_CACHE_STAT_INC(in_martian_dst);
1987 #ifdef CONFIG_IP_ROUTE_VERBOSE
1988 if (IN_DEV_LOG_MARTIANS(in_dev))
1989 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1990 &daddr, &saddr, dev->name);
1991 #endif
1992
1993 e_inval:
1994 err = -EINVAL;
1995 goto out;
1996
1997 e_nobufs:
1998 err = -ENOBUFS;
1999 goto out;
2000
2001 martian_source:
2002 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2003 goto out;
2004 }
2005
2006 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2007 u8 tos, struct net_device *dev)
2008 {
2009 int res;
2010
2011 rcu_read_lock();
2012
2013 /* Multicast recognition logic is moved from route cache to here.
2014 The problem was that too many Ethernet cards have broken/missing
2015 hardware multicast filters :-( As result the host on multicasting
2016 network acquires a lot of useless route cache entries, sort of
2017 SDR messages from all the world. Now we try to get rid of them.
2018 Really, provided software IP multicast filter is organized
2019 reasonably (at least, hashed), it does not result in a slowdown
2020 comparing with route cache reject entries.
2021 Note, that multicast routers are not affected, because
2022 route cache entry is created eventually.
2023 */
2024 if (ipv4_is_multicast(daddr)) {
2025 struct in_device *in_dev = __in_dev_get_rcu(dev);
2026 int our = 0;
2027
2028 if (in_dev)
2029 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2030 ip_hdr(skb)->protocol);
2031
2032 /* check l3 master if no match yet */
2033 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2034 struct in_device *l3_in_dev;
2035
2036 l3_in_dev = __in_dev_get_rcu(skb->dev);
2037 if (l3_in_dev)
2038 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2039 ip_hdr(skb)->protocol);
2040 }
2041
2042 res = -EINVAL;
2043 if (our
2044 #ifdef CONFIG_IP_MROUTE
2045 ||
2046 (!ipv4_is_local_multicast(daddr) &&
2047 IN_DEV_MFORWARD(in_dev))
2048 #endif
2049 ) {
2050 res = ip_route_input_mc(skb, daddr, saddr,
2051 tos, dev, our);
2052 }
2053 rcu_read_unlock();
2054 return res;
2055 }
2056 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2057 rcu_read_unlock();
2058 return res;
2059 }
2060 EXPORT_SYMBOL(ip_route_input_noref);
2061
2062 /* called with rcu_read_lock() */
2063 static struct rtable *__mkroute_output(const struct fib_result *res,
2064 const struct flowi4 *fl4, int orig_oif,
2065 struct net_device *dev_out,
2066 unsigned int flags)
2067 {
2068 struct fib_info *fi = res->fi;
2069 struct fib_nh_exception *fnhe;
2070 struct in_device *in_dev;
2071 u16 type = res->type;
2072 struct rtable *rth;
2073 bool do_cache;
2074
2075 in_dev = __in_dev_get_rcu(dev_out);
2076 if (!in_dev)
2077 return ERR_PTR(-EINVAL);
2078
2079 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2080 if (ipv4_is_loopback(fl4->saddr) &&
2081 !(dev_out->flags & IFF_LOOPBACK) &&
2082 !netif_is_l3_master(dev_out))
2083 return ERR_PTR(-EINVAL);
2084
2085 if (ipv4_is_lbcast(fl4->daddr))
2086 type = RTN_BROADCAST;
2087 else if (ipv4_is_multicast(fl4->daddr))
2088 type = RTN_MULTICAST;
2089 else if (ipv4_is_zeronet(fl4->daddr))
2090 return ERR_PTR(-EINVAL);
2091
2092 if (dev_out->flags & IFF_LOOPBACK)
2093 flags |= RTCF_LOCAL;
2094
2095 do_cache = true;
2096 if (type == RTN_BROADCAST) {
2097 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2098 fi = NULL;
2099 } else if (type == RTN_MULTICAST) {
2100 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2101 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2102 fl4->flowi4_proto))
2103 flags &= ~RTCF_LOCAL;
2104 else
2105 do_cache = false;
2106 /* If multicast route do not exist use
2107 * default one, but do not gateway in this case.
2108 * Yes, it is hack.
2109 */
2110 if (fi && res->prefixlen < 4)
2111 fi = NULL;
2112 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2113 (orig_oif != dev_out->ifindex)) {
2114 /* For local routes that require a particular output interface
2115 * we do not want to cache the result. Caching the result
2116 * causes incorrect behaviour when there are multiple source
2117 * addresses on the interface, the end result being that if the
2118 * intended recipient is waiting on that interface for the
2119 * packet he won't receive it because it will be delivered on
2120 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2121 * be set to the loopback interface as well.
2122 */
2123 fi = NULL;
2124 }
2125
2126 fnhe = NULL;
2127 do_cache &= fi != NULL;
2128 if (do_cache) {
2129 struct rtable __rcu **prth;
2130 struct fib_nh *nh = &FIB_RES_NH(*res);
2131
2132 fnhe = find_exception(nh, fl4->daddr);
2133 if (fnhe) {
2134 prth = &fnhe->fnhe_rth_output;
2135 rth = rcu_dereference(*prth);
2136 if (rth && rth->dst.expires &&
2137 time_after(jiffies, rth->dst.expires)) {
2138 ip_del_fnhe(nh, fl4->daddr);
2139 fnhe = NULL;
2140 } else {
2141 goto rt_cache;
2142 }
2143 }
2144
2145 if (unlikely(fl4->flowi4_flags &
2146 FLOWI_FLAG_KNOWN_NH &&
2147 !(nh->nh_gw &&
2148 nh->nh_scope == RT_SCOPE_LINK))) {
2149 do_cache = false;
2150 goto add;
2151 }
2152 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2153 rth = rcu_dereference(*prth);
2154
2155 rt_cache:
2156 if (rt_cache_valid(rth)) {
2157 dst_hold(&rth->dst);
2158 return rth;
2159 }
2160 }
2161
2162 add:
2163 rth = rt_dst_alloc(dev_out, flags, type,
2164 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2165 IN_DEV_CONF_GET(in_dev, NOXFRM),
2166 do_cache);
2167 if (!rth)
2168 return ERR_PTR(-ENOBUFS);
2169
2170 rth->rt_iif = orig_oif ? : 0;
2171 if (res->table)
2172 rth->rt_table_id = res->table->tb_id;
2173
2174 RT_CACHE_STAT_INC(out_slow_tot);
2175
2176 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2177 if (flags & RTCF_LOCAL &&
2178 !(dev_out->flags & IFF_LOOPBACK)) {
2179 rth->dst.output = ip_mc_output;
2180 RT_CACHE_STAT_INC(out_slow_mc);
2181 }
2182 #ifdef CONFIG_IP_MROUTE
2183 if (type == RTN_MULTICAST) {
2184 if (IN_DEV_MFORWARD(in_dev) &&
2185 !ipv4_is_local_multicast(fl4->daddr)) {
2186 rth->dst.input = ip_mr_input;
2187 rth->dst.output = ip_mc_output;
2188 }
2189 }
2190 #endif
2191 }
2192
2193 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2194 set_lwt_redirect(rth);
2195
2196 return rth;
2197 }
2198
2199 /*
2200 * Major route resolver routine.
2201 */
2202
2203 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2204 int mp_hash)
2205 {
2206 struct net_device *dev_out = NULL;
2207 __u8 tos = RT_FL_TOS(fl4);
2208 unsigned int flags = 0;
2209 struct fib_result res;
2210 struct rtable *rth;
2211 int orig_oif;
2212 int err = -ENETUNREACH;
2213
2214 res.tclassid = 0;
2215 res.fi = NULL;
2216 res.table = NULL;
2217
2218 orig_oif = fl4->flowi4_oif;
2219
2220 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2221 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2222 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2223 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2224
2225 rcu_read_lock();
2226 if (fl4->saddr) {
2227 rth = ERR_PTR(-EINVAL);
2228 if (ipv4_is_multicast(fl4->saddr) ||
2229 ipv4_is_lbcast(fl4->saddr) ||
2230 ipv4_is_zeronet(fl4->saddr))
2231 goto out;
2232
2233 /* I removed check for oif == dev_out->oif here.
2234 It was wrong for two reasons:
2235 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2236 is assigned to multiple interfaces.
2237 2. Moreover, we are allowed to send packets with saddr
2238 of another iface. --ANK
2239 */
2240
2241 if (fl4->flowi4_oif == 0 &&
2242 (ipv4_is_multicast(fl4->daddr) ||
2243 ipv4_is_lbcast(fl4->daddr))) {
2244 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2245 dev_out = __ip_dev_find(net, fl4->saddr, false);
2246 if (!dev_out)
2247 goto out;
2248
2249 /* Special hack: user can direct multicasts
2250 and limited broadcast via necessary interface
2251 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2252 This hack is not just for fun, it allows
2253 vic,vat and friends to work.
2254 They bind socket to loopback, set ttl to zero
2255 and expect that it will work.
2256 From the viewpoint of routing cache they are broken,
2257 because we are not allowed to build multicast path
2258 with loopback source addr (look, routing cache
2259 cannot know, that ttl is zero, so that packet
2260 will not leave this host and route is valid).
2261 Luckily, this hack is good workaround.
2262 */
2263
2264 fl4->flowi4_oif = dev_out->ifindex;
2265 goto make_route;
2266 }
2267
2268 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2269 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2270 if (!__ip_dev_find(net, fl4->saddr, false))
2271 goto out;
2272 }
2273 }
2274
2275
2276 if (fl4->flowi4_oif) {
2277 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2278 rth = ERR_PTR(-ENODEV);
2279 if (!dev_out)
2280 goto out;
2281
2282 /* RACE: Check return value of inet_select_addr instead. */
2283 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2284 rth = ERR_PTR(-ENETUNREACH);
2285 goto out;
2286 }
2287 if (ipv4_is_local_multicast(fl4->daddr) ||
2288 ipv4_is_lbcast(fl4->daddr) ||
2289 fl4->flowi4_proto == IPPROTO_IGMP) {
2290 if (!fl4->saddr)
2291 fl4->saddr = inet_select_addr(dev_out, 0,
2292 RT_SCOPE_LINK);
2293 goto make_route;
2294 }
2295 if (!fl4->saddr) {
2296 if (ipv4_is_multicast(fl4->daddr))
2297 fl4->saddr = inet_select_addr(dev_out, 0,
2298 fl4->flowi4_scope);
2299 else if (!fl4->daddr)
2300 fl4->saddr = inet_select_addr(dev_out, 0,
2301 RT_SCOPE_HOST);
2302 }
2303 }
2304
2305 if (!fl4->daddr) {
2306 fl4->daddr = fl4->saddr;
2307 if (!fl4->daddr)
2308 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2309 dev_out = net->loopback_dev;
2310 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2311 res.type = RTN_LOCAL;
2312 flags |= RTCF_LOCAL;
2313 goto make_route;
2314 }
2315
2316 err = fib_lookup(net, fl4, &res, 0);
2317 if (err) {
2318 res.fi = NULL;
2319 res.table = NULL;
2320 if (fl4->flowi4_oif &&
2321 (ipv4_is_multicast(fl4->daddr) ||
2322 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2323 /* Apparently, routing tables are wrong. Assume,
2324 that the destination is on link.
2325
2326 WHY? DW.
2327 Because we are allowed to send to iface
2328 even if it has NO routes and NO assigned
2329 addresses. When oif is specified, routing
2330 tables are looked up with only one purpose:
2331 to catch if destination is gatewayed, rather than
2332 direct. Moreover, if MSG_DONTROUTE is set,
2333 we send packet, ignoring both routing tables
2334 and ifaddr state. --ANK
2335
2336
2337 We could make it even if oif is unknown,
2338 likely IPv6, but we do not.
2339 */
2340
2341 if (fl4->saddr == 0)
2342 fl4->saddr = inet_select_addr(dev_out, 0,
2343 RT_SCOPE_LINK);
2344 res.type = RTN_UNICAST;
2345 goto make_route;
2346 }
2347 rth = ERR_PTR(err);
2348 goto out;
2349 }
2350
2351 if (res.type == RTN_LOCAL) {
2352 if (!fl4->saddr) {
2353 if (res.fi->fib_prefsrc)
2354 fl4->saddr = res.fi->fib_prefsrc;
2355 else
2356 fl4->saddr = fl4->daddr;
2357 }
2358
2359 /* L3 master device is the loopback for that domain */
2360 dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev;
2361 fl4->flowi4_oif = dev_out->ifindex;
2362 flags |= RTCF_LOCAL;
2363 goto make_route;
2364 }
2365
2366 fib_select_path(net, &res, fl4, mp_hash);
2367
2368 dev_out = FIB_RES_DEV(res);
2369 fl4->flowi4_oif = dev_out->ifindex;
2370
2371
2372 make_route:
2373 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2374
2375 out:
2376 rcu_read_unlock();
2377 return rth;
2378 }
2379 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2380
2381 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2382 {
2383 return NULL;
2384 }
2385
2386 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2387 {
2388 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2389
2390 return mtu ? : dst->dev->mtu;
2391 }
2392
2393 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2394 struct sk_buff *skb, u32 mtu)
2395 {
2396 }
2397
2398 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2399 struct sk_buff *skb)
2400 {
2401 }
2402
2403 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2404 unsigned long old)
2405 {
2406 return NULL;
2407 }
2408
2409 static struct dst_ops ipv4_dst_blackhole_ops = {
2410 .family = AF_INET,
2411 .check = ipv4_blackhole_dst_check,
2412 .mtu = ipv4_blackhole_mtu,
2413 .default_advmss = ipv4_default_advmss,
2414 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2415 .redirect = ipv4_rt_blackhole_redirect,
2416 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2417 .neigh_lookup = ipv4_neigh_lookup,
2418 };
2419
2420 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2421 {
2422 struct rtable *ort = (struct rtable *) dst_orig;
2423 struct rtable *rt;
2424
2425 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2426 if (rt) {
2427 struct dst_entry *new = &rt->dst;
2428
2429 new->__use = 1;
2430 new->input = dst_discard;
2431 new->output = dst_discard_out;
2432
2433 new->dev = ort->dst.dev;
2434 if (new->dev)
2435 dev_hold(new->dev);
2436
2437 rt->rt_is_input = ort->rt_is_input;
2438 rt->rt_iif = ort->rt_iif;
2439 rt->rt_pmtu = ort->rt_pmtu;
2440
2441 rt->rt_genid = rt_genid_ipv4(net);
2442 rt->rt_flags = ort->rt_flags;
2443 rt->rt_type = ort->rt_type;
2444 rt->rt_gateway = ort->rt_gateway;
2445 rt->rt_uses_gateway = ort->rt_uses_gateway;
2446
2447 INIT_LIST_HEAD(&rt->rt_uncached);
2448 dst_free(new);
2449 }
2450
2451 dst_release(dst_orig);
2452
2453 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2454 }
2455
2456 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2457 const struct sock *sk)
2458 {
2459 struct rtable *rt = __ip_route_output_key(net, flp4);
2460
2461 if (IS_ERR(rt))
2462 return rt;
2463
2464 if (flp4->flowi4_proto)
2465 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2466 flowi4_to_flowi(flp4),
2467 sk, 0);
2468
2469 return rt;
2470 }
2471 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2472
2473 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2474 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2475 u32 seq, int event)
2476 {
2477 struct rtable *rt = skb_rtable(skb);
2478 struct rtmsg *r;
2479 struct nlmsghdr *nlh;
2480 unsigned long expires = 0;
2481 u32 error;
2482 u32 metrics[RTAX_MAX];
2483
2484 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), 0);
2485 if (!nlh)
2486 return -EMSGSIZE;
2487
2488 r = nlmsg_data(nlh);
2489 r->rtm_family = AF_INET;
2490 r->rtm_dst_len = 32;
2491 r->rtm_src_len = 0;
2492 r->rtm_tos = fl4->flowi4_tos;
2493 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2494 if (nla_put_u32(skb, RTA_TABLE, table_id))
2495 goto nla_put_failure;
2496 r->rtm_type = rt->rt_type;
2497 r->rtm_scope = RT_SCOPE_UNIVERSE;
2498 r->rtm_protocol = RTPROT_UNSPEC;
2499 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2500 if (rt->rt_flags & RTCF_NOTIFY)
2501 r->rtm_flags |= RTM_F_NOTIFY;
2502 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2503 r->rtm_flags |= RTCF_DOREDIRECT;
2504
2505 if (nla_put_in_addr(skb, RTA_DST, dst))
2506 goto nla_put_failure;
2507 if (src) {
2508 r->rtm_src_len = 32;
2509 if (nla_put_in_addr(skb, RTA_SRC, src))
2510 goto nla_put_failure;
2511 }
2512 if (rt->dst.dev &&
2513 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2514 goto nla_put_failure;
2515 #ifdef CONFIG_IP_ROUTE_CLASSID
2516 if (rt->dst.tclassid &&
2517 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2518 goto nla_put_failure;
2519 #endif
2520 if (!rt_is_input_route(rt) &&
2521 fl4->saddr != src) {
2522 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2523 goto nla_put_failure;
2524 }
2525 if (rt->rt_uses_gateway &&
2526 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2527 goto nla_put_failure;
2528
2529 expires = rt->dst.expires;
2530 if (expires) {
2531 unsigned long now = jiffies;
2532
2533 if (time_before(now, expires))
2534 expires -= now;
2535 else
2536 expires = 0;
2537 }
2538
2539 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2540 if (rt->rt_pmtu && expires)
2541 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2542 if (rtnetlink_put_metrics(skb, metrics) < 0)
2543 goto nla_put_failure;
2544
2545 if (fl4->flowi4_mark &&
2546 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2547 goto nla_put_failure;
2548
2549 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2550 nla_put_u32(skb, RTA_UID,
2551 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2552 goto nla_put_failure;
2553
2554 error = rt->dst.error;
2555
2556 if (rt_is_input_route(rt)) {
2557 #ifdef CONFIG_IP_MROUTE
2558 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2559 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2560 int err = ipmr_get_route(net, skb,
2561 fl4->saddr, fl4->daddr,
2562 r, portid);
2563
2564 if (err <= 0) {
2565 if (err == 0)
2566 return 0;
2567 goto nla_put_failure;
2568 }
2569 } else
2570 #endif
2571 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2572 goto nla_put_failure;
2573 }
2574
2575 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2576 goto nla_put_failure;
2577
2578 nlmsg_end(skb, nlh);
2579 return 0;
2580
2581 nla_put_failure:
2582 nlmsg_cancel(skb, nlh);
2583 return -EMSGSIZE;
2584 }
2585
2586 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2587 {
2588 struct net *net = sock_net(in_skb->sk);
2589 struct rtmsg *rtm;
2590 struct nlattr *tb[RTA_MAX+1];
2591 struct rtable *rt = NULL;
2592 struct flowi4 fl4;
2593 __be32 dst = 0;
2594 __be32 src = 0;
2595 u32 iif;
2596 int err;
2597 int mark;
2598 struct sk_buff *skb;
2599 u32 table_id = RT_TABLE_MAIN;
2600 kuid_t uid;
2601
2602 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2603 if (err < 0)
2604 goto errout;
2605
2606 rtm = nlmsg_data(nlh);
2607
2608 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2609 if (!skb) {
2610 err = -ENOBUFS;
2611 goto errout;
2612 }
2613
2614 /* Reserve room for dummy headers, this skb can pass
2615 through good chunk of routing engine.
2616 */
2617 skb_reset_mac_header(skb);
2618 skb_reset_network_header(skb);
2619
2620 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2621 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2622 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2623
2624 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2625 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2626 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2627 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2628 if (tb[RTA_UID])
2629 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2630 else
2631 uid = (iif ? INVALID_UID : current_uid());
2632
2633 memset(&fl4, 0, sizeof(fl4));
2634 fl4.daddr = dst;
2635 fl4.saddr = src;
2636 fl4.flowi4_tos = rtm->rtm_tos;
2637 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2638 fl4.flowi4_mark = mark;
2639 fl4.flowi4_uid = uid;
2640
2641 if (iif) {
2642 struct net_device *dev;
2643
2644 dev = __dev_get_by_index(net, iif);
2645 if (!dev) {
2646 err = -ENODEV;
2647 goto errout_free;
2648 }
2649
2650 skb->protocol = htons(ETH_P_IP);
2651 skb->dev = dev;
2652 skb->mark = mark;
2653 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2654
2655 rt = skb_rtable(skb);
2656 if (err == 0 && rt->dst.error)
2657 err = -rt->dst.error;
2658 } else {
2659 rt = ip_route_output_key(net, &fl4);
2660
2661 err = 0;
2662 if (IS_ERR(rt))
2663 err = PTR_ERR(rt);
2664 }
2665
2666 if (err)
2667 goto errout_free;
2668
2669 skb_dst_set(skb, &rt->dst);
2670 if (rtm->rtm_flags & RTM_F_NOTIFY)
2671 rt->rt_flags |= RTCF_NOTIFY;
2672
2673 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2674 table_id = rt->rt_table_id;
2675
2676 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2677 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2678 RTM_NEWROUTE);
2679 if (err < 0)
2680 goto errout_free;
2681
2682 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2683 errout:
2684 return err;
2685
2686 errout_free:
2687 kfree_skb(skb);
2688 goto errout;
2689 }
2690
2691 void ip_rt_multicast_event(struct in_device *in_dev)
2692 {
2693 rt_cache_flush(dev_net(in_dev->dev));
2694 }
2695
2696 #ifdef CONFIG_SYSCTL
2697 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2698 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2699 static int ip_rt_gc_elasticity __read_mostly = 8;
2700
2701 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2702 void __user *buffer,
2703 size_t *lenp, loff_t *ppos)
2704 {
2705 struct net *net = (struct net *)__ctl->extra1;
2706
2707 if (write) {
2708 rt_cache_flush(net);
2709 fnhe_genid_bump(net);
2710 return 0;
2711 }
2712
2713 return -EINVAL;
2714 }
2715
2716 static struct ctl_table ipv4_route_table[] = {
2717 {
2718 .procname = "gc_thresh",
2719 .data = &ipv4_dst_ops.gc_thresh,
2720 .maxlen = sizeof(int),
2721 .mode = 0644,
2722 .proc_handler = proc_dointvec,
2723 },
2724 {
2725 .procname = "max_size",
2726 .data = &ip_rt_max_size,
2727 .maxlen = sizeof(int),
2728 .mode = 0644,
2729 .proc_handler = proc_dointvec,
2730 },
2731 {
2732 /* Deprecated. Use gc_min_interval_ms */
2733
2734 .procname = "gc_min_interval",
2735 .data = &ip_rt_gc_min_interval,
2736 .maxlen = sizeof(int),
2737 .mode = 0644,
2738 .proc_handler = proc_dointvec_jiffies,
2739 },
2740 {
2741 .procname = "gc_min_interval_ms",
2742 .data = &ip_rt_gc_min_interval,
2743 .maxlen = sizeof(int),
2744 .mode = 0644,
2745 .proc_handler = proc_dointvec_ms_jiffies,
2746 },
2747 {
2748 .procname = "gc_timeout",
2749 .data = &ip_rt_gc_timeout,
2750 .maxlen = sizeof(int),
2751 .mode = 0644,
2752 .proc_handler = proc_dointvec_jiffies,
2753 },
2754 {
2755 .procname = "gc_interval",
2756 .data = &ip_rt_gc_interval,
2757 .maxlen = sizeof(int),
2758 .mode = 0644,
2759 .proc_handler = proc_dointvec_jiffies,
2760 },
2761 {
2762 .procname = "redirect_load",
2763 .data = &ip_rt_redirect_load,
2764 .maxlen = sizeof(int),
2765 .mode = 0644,
2766 .proc_handler = proc_dointvec,
2767 },
2768 {
2769 .procname = "redirect_number",
2770 .data = &ip_rt_redirect_number,
2771 .maxlen = sizeof(int),
2772 .mode = 0644,
2773 .proc_handler = proc_dointvec,
2774 },
2775 {
2776 .procname = "redirect_silence",
2777 .data = &ip_rt_redirect_silence,
2778 .maxlen = sizeof(int),
2779 .mode = 0644,
2780 .proc_handler = proc_dointvec,
2781 },
2782 {
2783 .procname = "error_cost",
2784 .data = &ip_rt_error_cost,
2785 .maxlen = sizeof(int),
2786 .mode = 0644,
2787 .proc_handler = proc_dointvec,
2788 },
2789 {
2790 .procname = "error_burst",
2791 .data = &ip_rt_error_burst,
2792 .maxlen = sizeof(int),
2793 .mode = 0644,
2794 .proc_handler = proc_dointvec,
2795 },
2796 {
2797 .procname = "gc_elasticity",
2798 .data = &ip_rt_gc_elasticity,
2799 .maxlen = sizeof(int),
2800 .mode = 0644,
2801 .proc_handler = proc_dointvec,
2802 },
2803 {
2804 .procname = "mtu_expires",
2805 .data = &ip_rt_mtu_expires,
2806 .maxlen = sizeof(int),
2807 .mode = 0644,
2808 .proc_handler = proc_dointvec_jiffies,
2809 },
2810 {
2811 .procname = "min_pmtu",
2812 .data = &ip_rt_min_pmtu,
2813 .maxlen = sizeof(int),
2814 .mode = 0644,
2815 .proc_handler = proc_dointvec,
2816 },
2817 {
2818 .procname = "min_adv_mss",
2819 .data = &ip_rt_min_advmss,
2820 .maxlen = sizeof(int),
2821 .mode = 0644,
2822 .proc_handler = proc_dointvec,
2823 },
2824 { }
2825 };
2826
2827 static struct ctl_table ipv4_route_flush_table[] = {
2828 {
2829 .procname = "flush",
2830 .maxlen = sizeof(int),
2831 .mode = 0200,
2832 .proc_handler = ipv4_sysctl_rtcache_flush,
2833 },
2834 { },
2835 };
2836
2837 static __net_init int sysctl_route_net_init(struct net *net)
2838 {
2839 struct ctl_table *tbl;
2840
2841 tbl = ipv4_route_flush_table;
2842 if (!net_eq(net, &init_net)) {
2843 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2844 if (!tbl)
2845 goto err_dup;
2846
2847 /* Don't export sysctls to unprivileged users */
2848 if (net->user_ns != &init_user_ns)
2849 tbl[0].procname = NULL;
2850 }
2851 tbl[0].extra1 = net;
2852
2853 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2854 if (!net->ipv4.route_hdr)
2855 goto err_reg;
2856 return 0;
2857
2858 err_reg:
2859 if (tbl != ipv4_route_flush_table)
2860 kfree(tbl);
2861 err_dup:
2862 return -ENOMEM;
2863 }
2864
2865 static __net_exit void sysctl_route_net_exit(struct net *net)
2866 {
2867 struct ctl_table *tbl;
2868
2869 tbl = net->ipv4.route_hdr->ctl_table_arg;
2870 unregister_net_sysctl_table(net->ipv4.route_hdr);
2871 BUG_ON(tbl == ipv4_route_flush_table);
2872 kfree(tbl);
2873 }
2874
2875 static __net_initdata struct pernet_operations sysctl_route_ops = {
2876 .init = sysctl_route_net_init,
2877 .exit = sysctl_route_net_exit,
2878 };
2879 #endif
2880
2881 static __net_init int rt_genid_init(struct net *net)
2882 {
2883 atomic_set(&net->ipv4.rt_genid, 0);
2884 atomic_set(&net->fnhe_genid, 0);
2885 get_random_bytes(&net->ipv4.dev_addr_genid,
2886 sizeof(net->ipv4.dev_addr_genid));
2887 return 0;
2888 }
2889
2890 static __net_initdata struct pernet_operations rt_genid_ops = {
2891 .init = rt_genid_init,
2892 };
2893
2894 static int __net_init ipv4_inetpeer_init(struct net *net)
2895 {
2896 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2897
2898 if (!bp)
2899 return -ENOMEM;
2900 inet_peer_base_init(bp);
2901 net->ipv4.peers = bp;
2902 return 0;
2903 }
2904
2905 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2906 {
2907 struct inet_peer_base *bp = net->ipv4.peers;
2908
2909 net->ipv4.peers = NULL;
2910 inetpeer_invalidate_tree(bp);
2911 kfree(bp);
2912 }
2913
2914 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2915 .init = ipv4_inetpeer_init,
2916 .exit = ipv4_inetpeer_exit,
2917 };
2918
2919 #ifdef CONFIG_IP_ROUTE_CLASSID
2920 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2921 #endif /* CONFIG_IP_ROUTE_CLASSID */
2922
2923 int __init ip_rt_init(void)
2924 {
2925 int rc = 0;
2926 int cpu;
2927
2928 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2929 if (!ip_idents)
2930 panic("IP: failed to allocate ip_idents\n");
2931
2932 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2933
2934 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2935 if (!ip_tstamps)
2936 panic("IP: failed to allocate ip_tstamps\n");
2937
2938 for_each_possible_cpu(cpu) {
2939 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2940
2941 INIT_LIST_HEAD(&ul->head);
2942 spin_lock_init(&ul->lock);
2943 }
2944 #ifdef CONFIG_IP_ROUTE_CLASSID
2945 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2946 if (!ip_rt_acct)
2947 panic("IP: failed to allocate ip_rt_acct\n");
2948 #endif
2949
2950 ipv4_dst_ops.kmem_cachep =
2951 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2952 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2953
2954 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2955
2956 if (dst_entries_init(&ipv4_dst_ops) < 0)
2957 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2958
2959 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2960 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2961
2962 ipv4_dst_ops.gc_thresh = ~0;
2963 ip_rt_max_size = INT_MAX;
2964
2965 devinet_init();
2966 ip_fib_init();
2967
2968 if (ip_rt_proc_init())
2969 pr_err("Unable to create route proc files\n");
2970 #ifdef CONFIG_XFRM
2971 xfrm_init();
2972 xfrm4_init();
2973 #endif
2974 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2975
2976 #ifdef CONFIG_SYSCTL
2977 register_pernet_subsys(&sysctl_route_ops);
2978 #endif
2979 register_pernet_subsys(&rt_genid_ops);
2980 register_pernet_subsys(&ipv4_inetpeer_ops);
2981 return rc;
2982 }
2983
2984 #ifdef CONFIG_SYSCTL
2985 /*
2986 * We really need to sanitize the damn ipv4 init order, then all
2987 * this nonsense will go away.
2988 */
2989 void __init ip_static_sysctl_init(void)
2990 {
2991 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2992 }
2993 #endif
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