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