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Merge tag 'xfs-pnfs-for-linus-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel...
[mirror_ubuntu-bionic-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/net_namespace.h>
95 #include <net/protocol.h>
96 #include <net/ip.h>
97 #include <net/route.h>
98 #include <net/inetpeer.h>
99 #include <net/sock.h>
100 #include <net/ip_fib.h>
101 #include <net/arp.h>
102 #include <net/tcp.h>
103 #include <net/icmp.h>
104 #include <net/xfrm.h>
105 #include <net/netevent.h>
106 #include <net/rtnetlink.h>
107 #ifdef CONFIG_SYSCTL
108 #include <linux/sysctl.h>
109 #include <linux/kmemleak.h>
110 #endif
111 #include <net/secure_seq.h>
112
113 #define RT_FL_TOS(oldflp4) \
114 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
115
116 #define RT_GC_TIMEOUT (300*HZ)
117
118 static int ip_rt_max_size;
119 static int ip_rt_redirect_number __read_mostly = 9;
120 static int ip_rt_redirect_load __read_mostly = HZ / 50;
121 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
122 static int ip_rt_error_cost __read_mostly = HZ;
123 static int ip_rt_error_burst __read_mostly = 5 * HZ;
124 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
125 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
126 static int ip_rt_min_advmss __read_mostly = 256;
127
128 /*
129 * Interface to generic destination cache.
130 */
131
132 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
133 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
134 static unsigned int ipv4_mtu(const struct dst_entry *dst);
135 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
136 static void ipv4_link_failure(struct sk_buff *skb);
137 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
138 struct sk_buff *skb, u32 mtu);
139 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
140 struct sk_buff *skb);
141 static void ipv4_dst_destroy(struct dst_entry *dst);
142
143 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
144 {
145 WARN_ON(1);
146 return NULL;
147 }
148
149 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
150 struct sk_buff *skb,
151 const void *daddr);
152
153 static struct dst_ops ipv4_dst_ops = {
154 .family = AF_INET,
155 .protocol = cpu_to_be16(ETH_P_IP),
156 .check = ipv4_dst_check,
157 .default_advmss = ipv4_default_advmss,
158 .mtu = ipv4_mtu,
159 .cow_metrics = ipv4_cow_metrics,
160 .destroy = ipv4_dst_destroy,
161 .negative_advice = ipv4_negative_advice,
162 .link_failure = ipv4_link_failure,
163 .update_pmtu = ip_rt_update_pmtu,
164 .redirect = ip_do_redirect,
165 .local_out = __ip_local_out,
166 .neigh_lookup = ipv4_neigh_lookup,
167 };
168
169 #define ECN_OR_COST(class) TC_PRIO_##class
170
171 const __u8 ip_tos2prio[16] = {
172 TC_PRIO_BESTEFFORT,
173 ECN_OR_COST(BESTEFFORT),
174 TC_PRIO_BESTEFFORT,
175 ECN_OR_COST(BESTEFFORT),
176 TC_PRIO_BULK,
177 ECN_OR_COST(BULK),
178 TC_PRIO_BULK,
179 ECN_OR_COST(BULK),
180 TC_PRIO_INTERACTIVE,
181 ECN_OR_COST(INTERACTIVE),
182 TC_PRIO_INTERACTIVE,
183 ECN_OR_COST(INTERACTIVE),
184 TC_PRIO_INTERACTIVE_BULK,
185 ECN_OR_COST(INTERACTIVE_BULK),
186 TC_PRIO_INTERACTIVE_BULK,
187 ECN_OR_COST(INTERACTIVE_BULK)
188 };
189 EXPORT_SYMBOL(ip_tos2prio);
190
191 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
192 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
193
194 #ifdef CONFIG_PROC_FS
195 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
196 {
197 if (*pos)
198 return NULL;
199 return SEQ_START_TOKEN;
200 }
201
202 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
203 {
204 ++*pos;
205 return NULL;
206 }
207
208 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
209 {
210 }
211
212 static int rt_cache_seq_show(struct seq_file *seq, void *v)
213 {
214 if (v == SEQ_START_TOKEN)
215 seq_printf(seq, "%-127s\n",
216 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
217 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
218 "HHUptod\tSpecDst");
219 return 0;
220 }
221
222 static const struct seq_operations rt_cache_seq_ops = {
223 .start = rt_cache_seq_start,
224 .next = rt_cache_seq_next,
225 .stop = rt_cache_seq_stop,
226 .show = rt_cache_seq_show,
227 };
228
229 static int rt_cache_seq_open(struct inode *inode, struct file *file)
230 {
231 return seq_open(file, &rt_cache_seq_ops);
232 }
233
234 static const struct file_operations rt_cache_seq_fops = {
235 .owner = THIS_MODULE,
236 .open = rt_cache_seq_open,
237 .read = seq_read,
238 .llseek = seq_lseek,
239 .release = seq_release,
240 };
241
242
243 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
244 {
245 int cpu;
246
247 if (*pos == 0)
248 return SEQ_START_TOKEN;
249
250 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
251 if (!cpu_possible(cpu))
252 continue;
253 *pos = cpu+1;
254 return &per_cpu(rt_cache_stat, cpu);
255 }
256 return NULL;
257 }
258
259 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
260 {
261 int cpu;
262
263 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
264 if (!cpu_possible(cpu))
265 continue;
266 *pos = cpu+1;
267 return &per_cpu(rt_cache_stat, cpu);
268 }
269 return NULL;
270
271 }
272
273 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
274 {
275
276 }
277
278 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
279 {
280 struct rt_cache_stat *st = v;
281
282 if (v == SEQ_START_TOKEN) {
283 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");
284 return 0;
285 }
286
287 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
288 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
289 dst_entries_get_slow(&ipv4_dst_ops),
290 0, /* st->in_hit */
291 st->in_slow_tot,
292 st->in_slow_mc,
293 st->in_no_route,
294 st->in_brd,
295 st->in_martian_dst,
296 st->in_martian_src,
297
298 0, /* st->out_hit */
299 st->out_slow_tot,
300 st->out_slow_mc,
301
302 0, /* st->gc_total */
303 0, /* st->gc_ignored */
304 0, /* st->gc_goal_miss */
305 0, /* st->gc_dst_overflow */
306 0, /* st->in_hlist_search */
307 0 /* st->out_hlist_search */
308 );
309 return 0;
310 }
311
312 static const struct seq_operations rt_cpu_seq_ops = {
313 .start = rt_cpu_seq_start,
314 .next = rt_cpu_seq_next,
315 .stop = rt_cpu_seq_stop,
316 .show = rt_cpu_seq_show,
317 };
318
319
320 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
321 {
322 return seq_open(file, &rt_cpu_seq_ops);
323 }
324
325 static const struct file_operations rt_cpu_seq_fops = {
326 .owner = THIS_MODULE,
327 .open = rt_cpu_seq_open,
328 .read = seq_read,
329 .llseek = seq_lseek,
330 .release = seq_release,
331 };
332
333 #ifdef CONFIG_IP_ROUTE_CLASSID
334 static int rt_acct_proc_show(struct seq_file *m, void *v)
335 {
336 struct ip_rt_acct *dst, *src;
337 unsigned int i, j;
338
339 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
340 if (!dst)
341 return -ENOMEM;
342
343 for_each_possible_cpu(i) {
344 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
345 for (j = 0; j < 256; j++) {
346 dst[j].o_bytes += src[j].o_bytes;
347 dst[j].o_packets += src[j].o_packets;
348 dst[j].i_bytes += src[j].i_bytes;
349 dst[j].i_packets += src[j].i_packets;
350 }
351 }
352
353 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
354 kfree(dst);
355 return 0;
356 }
357
358 static int rt_acct_proc_open(struct inode *inode, struct file *file)
359 {
360 return single_open(file, rt_acct_proc_show, NULL);
361 }
362
363 static const struct file_operations rt_acct_proc_fops = {
364 .owner = THIS_MODULE,
365 .open = rt_acct_proc_open,
366 .read = seq_read,
367 .llseek = seq_lseek,
368 .release = single_release,
369 };
370 #endif
371
372 static int __net_init ip_rt_do_proc_init(struct net *net)
373 {
374 struct proc_dir_entry *pde;
375
376 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
377 &rt_cache_seq_fops);
378 if (!pde)
379 goto err1;
380
381 pde = proc_create("rt_cache", S_IRUGO,
382 net->proc_net_stat, &rt_cpu_seq_fops);
383 if (!pde)
384 goto err2;
385
386 #ifdef CONFIG_IP_ROUTE_CLASSID
387 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
388 if (!pde)
389 goto err3;
390 #endif
391 return 0;
392
393 #ifdef CONFIG_IP_ROUTE_CLASSID
394 err3:
395 remove_proc_entry("rt_cache", net->proc_net_stat);
396 #endif
397 err2:
398 remove_proc_entry("rt_cache", net->proc_net);
399 err1:
400 return -ENOMEM;
401 }
402
403 static void __net_exit ip_rt_do_proc_exit(struct net *net)
404 {
405 remove_proc_entry("rt_cache", net->proc_net_stat);
406 remove_proc_entry("rt_cache", net->proc_net);
407 #ifdef CONFIG_IP_ROUTE_CLASSID
408 remove_proc_entry("rt_acct", net->proc_net);
409 #endif
410 }
411
412 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
413 .init = ip_rt_do_proc_init,
414 .exit = ip_rt_do_proc_exit,
415 };
416
417 static int __init ip_rt_proc_init(void)
418 {
419 return register_pernet_subsys(&ip_rt_proc_ops);
420 }
421
422 #else
423 static inline int ip_rt_proc_init(void)
424 {
425 return 0;
426 }
427 #endif /* CONFIG_PROC_FS */
428
429 static inline bool rt_is_expired(const struct rtable *rth)
430 {
431 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
432 }
433
434 void rt_cache_flush(struct net *net)
435 {
436 rt_genid_bump_ipv4(net);
437 }
438
439 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
440 struct sk_buff *skb,
441 const void *daddr)
442 {
443 struct net_device *dev = dst->dev;
444 const __be32 *pkey = daddr;
445 const struct rtable *rt;
446 struct neighbour *n;
447
448 rt = (const struct rtable *) dst;
449 if (rt->rt_gateway)
450 pkey = (const __be32 *) &rt->rt_gateway;
451 else if (skb)
452 pkey = &ip_hdr(skb)->daddr;
453
454 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
455 if (n)
456 return n;
457 return neigh_create(&arp_tbl, pkey, dev);
458 }
459
460 #define IP_IDENTS_SZ 2048u
461 struct ip_ident_bucket {
462 atomic_t id;
463 u32 stamp32;
464 };
465
466 static struct ip_ident_bucket *ip_idents __read_mostly;
467
468 /* In order to protect privacy, we add a perturbation to identifiers
469 * if one generator is seldom used. This makes hard for an attacker
470 * to infer how many packets were sent between two points in time.
471 */
472 u32 ip_idents_reserve(u32 hash, int segs)
473 {
474 struct ip_ident_bucket *bucket = ip_idents + hash % IP_IDENTS_SZ;
475 u32 old = ACCESS_ONCE(bucket->stamp32);
476 u32 now = (u32)jiffies;
477 u32 delta = 0;
478
479 if (old != now && cmpxchg(&bucket->stamp32, old, now) == old)
480 delta = prandom_u32_max(now - old);
481
482 return atomic_add_return(segs + delta, &bucket->id) - segs;
483 }
484 EXPORT_SYMBOL(ip_idents_reserve);
485
486 void __ip_select_ident(struct iphdr *iph, int segs)
487 {
488 static u32 ip_idents_hashrnd __read_mostly;
489 u32 hash, id;
490
491 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
492
493 hash = jhash_3words((__force u32)iph->daddr,
494 (__force u32)iph->saddr,
495 iph->protocol,
496 ip_idents_hashrnd);
497 id = ip_idents_reserve(hash, segs);
498 iph->id = htons(id);
499 }
500 EXPORT_SYMBOL(__ip_select_ident);
501
502 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
503 const struct iphdr *iph,
504 int oif, u8 tos,
505 u8 prot, u32 mark, int flow_flags)
506 {
507 if (sk) {
508 const struct inet_sock *inet = inet_sk(sk);
509
510 oif = sk->sk_bound_dev_if;
511 mark = sk->sk_mark;
512 tos = RT_CONN_FLAGS(sk);
513 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
514 }
515 flowi4_init_output(fl4, oif, mark, tos,
516 RT_SCOPE_UNIVERSE, prot,
517 flow_flags,
518 iph->daddr, iph->saddr, 0, 0);
519 }
520
521 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
522 const struct sock *sk)
523 {
524 const struct iphdr *iph = ip_hdr(skb);
525 int oif = skb->dev->ifindex;
526 u8 tos = RT_TOS(iph->tos);
527 u8 prot = iph->protocol;
528 u32 mark = skb->mark;
529
530 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
531 }
532
533 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
534 {
535 const struct inet_sock *inet = inet_sk(sk);
536 const struct ip_options_rcu *inet_opt;
537 __be32 daddr = inet->inet_daddr;
538
539 rcu_read_lock();
540 inet_opt = rcu_dereference(inet->inet_opt);
541 if (inet_opt && inet_opt->opt.srr)
542 daddr = inet_opt->opt.faddr;
543 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
544 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
545 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
546 inet_sk_flowi_flags(sk),
547 daddr, inet->inet_saddr, 0, 0);
548 rcu_read_unlock();
549 }
550
551 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
552 const struct sk_buff *skb)
553 {
554 if (skb)
555 build_skb_flow_key(fl4, skb, sk);
556 else
557 build_sk_flow_key(fl4, sk);
558 }
559
560 static inline void rt_free(struct rtable *rt)
561 {
562 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
563 }
564
565 static DEFINE_SPINLOCK(fnhe_lock);
566
567 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
568 {
569 struct rtable *rt;
570
571 rt = rcu_dereference(fnhe->fnhe_rth_input);
572 if (rt) {
573 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
574 rt_free(rt);
575 }
576 rt = rcu_dereference(fnhe->fnhe_rth_output);
577 if (rt) {
578 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
579 rt_free(rt);
580 }
581 }
582
583 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
584 {
585 struct fib_nh_exception *fnhe, *oldest;
586
587 oldest = rcu_dereference(hash->chain);
588 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
589 fnhe = rcu_dereference(fnhe->fnhe_next)) {
590 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
591 oldest = fnhe;
592 }
593 fnhe_flush_routes(oldest);
594 return oldest;
595 }
596
597 static inline u32 fnhe_hashfun(__be32 daddr)
598 {
599 static u32 fnhe_hashrnd __read_mostly;
600 u32 hval;
601
602 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
603 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
604 return hash_32(hval, FNHE_HASH_SHIFT);
605 }
606
607 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
608 {
609 rt->rt_pmtu = fnhe->fnhe_pmtu;
610 rt->dst.expires = fnhe->fnhe_expires;
611
612 if (fnhe->fnhe_gw) {
613 rt->rt_flags |= RTCF_REDIRECTED;
614 rt->rt_gateway = fnhe->fnhe_gw;
615 rt->rt_uses_gateway = 1;
616 }
617 }
618
619 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
620 u32 pmtu, unsigned long expires)
621 {
622 struct fnhe_hash_bucket *hash;
623 struct fib_nh_exception *fnhe;
624 struct rtable *rt;
625 unsigned int i;
626 int depth;
627 u32 hval = fnhe_hashfun(daddr);
628
629 spin_lock_bh(&fnhe_lock);
630
631 hash = rcu_dereference(nh->nh_exceptions);
632 if (!hash) {
633 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
634 if (!hash)
635 goto out_unlock;
636 rcu_assign_pointer(nh->nh_exceptions, hash);
637 }
638
639 hash += hval;
640
641 depth = 0;
642 for (fnhe = rcu_dereference(hash->chain); fnhe;
643 fnhe = rcu_dereference(fnhe->fnhe_next)) {
644 if (fnhe->fnhe_daddr == daddr)
645 break;
646 depth++;
647 }
648
649 if (fnhe) {
650 if (gw)
651 fnhe->fnhe_gw = gw;
652 if (pmtu) {
653 fnhe->fnhe_pmtu = pmtu;
654 fnhe->fnhe_expires = max(1UL, expires);
655 }
656 /* Update all cached dsts too */
657 rt = rcu_dereference(fnhe->fnhe_rth_input);
658 if (rt)
659 fill_route_from_fnhe(rt, fnhe);
660 rt = rcu_dereference(fnhe->fnhe_rth_output);
661 if (rt)
662 fill_route_from_fnhe(rt, fnhe);
663 } else {
664 if (depth > FNHE_RECLAIM_DEPTH)
665 fnhe = fnhe_oldest(hash);
666 else {
667 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
668 if (!fnhe)
669 goto out_unlock;
670
671 fnhe->fnhe_next = hash->chain;
672 rcu_assign_pointer(hash->chain, fnhe);
673 }
674 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
675 fnhe->fnhe_daddr = daddr;
676 fnhe->fnhe_gw = gw;
677 fnhe->fnhe_pmtu = pmtu;
678 fnhe->fnhe_expires = expires;
679
680 /* Exception created; mark the cached routes for the nexthop
681 * stale, so anyone caching it rechecks if this exception
682 * applies to them.
683 */
684 rt = rcu_dereference(nh->nh_rth_input);
685 if (rt)
686 rt->dst.obsolete = DST_OBSOLETE_KILL;
687
688 for_each_possible_cpu(i) {
689 struct rtable __rcu **prt;
690 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
691 rt = rcu_dereference(*prt);
692 if (rt)
693 rt->dst.obsolete = DST_OBSOLETE_KILL;
694 }
695 }
696
697 fnhe->fnhe_stamp = jiffies;
698
699 out_unlock:
700 spin_unlock_bh(&fnhe_lock);
701 }
702
703 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
704 bool kill_route)
705 {
706 __be32 new_gw = icmp_hdr(skb)->un.gateway;
707 __be32 old_gw = ip_hdr(skb)->saddr;
708 struct net_device *dev = skb->dev;
709 struct in_device *in_dev;
710 struct fib_result res;
711 struct neighbour *n;
712 struct net *net;
713
714 switch (icmp_hdr(skb)->code & 7) {
715 case ICMP_REDIR_NET:
716 case ICMP_REDIR_NETTOS:
717 case ICMP_REDIR_HOST:
718 case ICMP_REDIR_HOSTTOS:
719 break;
720
721 default:
722 return;
723 }
724
725 if (rt->rt_gateway != old_gw)
726 return;
727
728 in_dev = __in_dev_get_rcu(dev);
729 if (!in_dev)
730 return;
731
732 net = dev_net(dev);
733 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
734 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
735 ipv4_is_zeronet(new_gw))
736 goto reject_redirect;
737
738 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
739 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
740 goto reject_redirect;
741 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
742 goto reject_redirect;
743 } else {
744 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
745 goto reject_redirect;
746 }
747
748 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
749 if (!IS_ERR(n)) {
750 if (!(n->nud_state & NUD_VALID)) {
751 neigh_event_send(n, NULL);
752 } else {
753 if (fib_lookup(net, fl4, &res) == 0) {
754 struct fib_nh *nh = &FIB_RES_NH(res);
755
756 update_or_create_fnhe(nh, fl4->daddr, new_gw,
757 0, 0);
758 }
759 if (kill_route)
760 rt->dst.obsolete = DST_OBSOLETE_KILL;
761 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
762 }
763 neigh_release(n);
764 }
765 return;
766
767 reject_redirect:
768 #ifdef CONFIG_IP_ROUTE_VERBOSE
769 if (IN_DEV_LOG_MARTIANS(in_dev)) {
770 const struct iphdr *iph = (const struct iphdr *) skb->data;
771 __be32 daddr = iph->daddr;
772 __be32 saddr = iph->saddr;
773
774 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
775 " Advised path = %pI4 -> %pI4\n",
776 &old_gw, dev->name, &new_gw,
777 &saddr, &daddr);
778 }
779 #endif
780 ;
781 }
782
783 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
784 {
785 struct rtable *rt;
786 struct flowi4 fl4;
787 const struct iphdr *iph = (const struct iphdr *) skb->data;
788 int oif = skb->dev->ifindex;
789 u8 tos = RT_TOS(iph->tos);
790 u8 prot = iph->protocol;
791 u32 mark = skb->mark;
792
793 rt = (struct rtable *) dst;
794
795 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
796 __ip_do_redirect(rt, skb, &fl4, true);
797 }
798
799 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
800 {
801 struct rtable *rt = (struct rtable *)dst;
802 struct dst_entry *ret = dst;
803
804 if (rt) {
805 if (dst->obsolete > 0) {
806 ip_rt_put(rt);
807 ret = NULL;
808 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
809 rt->dst.expires) {
810 ip_rt_put(rt);
811 ret = NULL;
812 }
813 }
814 return ret;
815 }
816
817 /*
818 * Algorithm:
819 * 1. The first ip_rt_redirect_number redirects are sent
820 * with exponential backoff, then we stop sending them at all,
821 * assuming that the host ignores our redirects.
822 * 2. If we did not see packets requiring redirects
823 * during ip_rt_redirect_silence, we assume that the host
824 * forgot redirected route and start to send redirects again.
825 *
826 * This algorithm is much cheaper and more intelligent than dumb load limiting
827 * in icmp.c.
828 *
829 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
830 * and "frag. need" (breaks PMTU discovery) in icmp.c.
831 */
832
833 void ip_rt_send_redirect(struct sk_buff *skb)
834 {
835 struct rtable *rt = skb_rtable(skb);
836 struct in_device *in_dev;
837 struct inet_peer *peer;
838 struct net *net;
839 int log_martians;
840
841 rcu_read_lock();
842 in_dev = __in_dev_get_rcu(rt->dst.dev);
843 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
844 rcu_read_unlock();
845 return;
846 }
847 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
848 rcu_read_unlock();
849
850 net = dev_net(rt->dst.dev);
851 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
852 if (!peer) {
853 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
854 rt_nexthop(rt, ip_hdr(skb)->daddr));
855 return;
856 }
857
858 /* No redirected packets during ip_rt_redirect_silence;
859 * reset the algorithm.
860 */
861 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
862 peer->rate_tokens = 0;
863
864 /* Too many ignored redirects; do not send anything
865 * set dst.rate_last to the last seen redirected packet.
866 */
867 if (peer->rate_tokens >= ip_rt_redirect_number) {
868 peer->rate_last = jiffies;
869 goto out_put_peer;
870 }
871
872 /* Check for load limit; set rate_last to the latest sent
873 * redirect.
874 */
875 if (peer->rate_tokens == 0 ||
876 time_after(jiffies,
877 (peer->rate_last +
878 (ip_rt_redirect_load << peer->rate_tokens)))) {
879 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
880
881 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
882 peer->rate_last = jiffies;
883 ++peer->rate_tokens;
884 #ifdef CONFIG_IP_ROUTE_VERBOSE
885 if (log_martians &&
886 peer->rate_tokens == ip_rt_redirect_number)
887 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
888 &ip_hdr(skb)->saddr, inet_iif(skb),
889 &ip_hdr(skb)->daddr, &gw);
890 #endif
891 }
892 out_put_peer:
893 inet_putpeer(peer);
894 }
895
896 static int ip_error(struct sk_buff *skb)
897 {
898 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
899 struct rtable *rt = skb_rtable(skb);
900 struct inet_peer *peer;
901 unsigned long now;
902 struct net *net;
903 bool send;
904 int code;
905
906 net = dev_net(rt->dst.dev);
907 if (!IN_DEV_FORWARD(in_dev)) {
908 switch (rt->dst.error) {
909 case EHOSTUNREACH:
910 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
911 break;
912
913 case ENETUNREACH:
914 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
915 break;
916 }
917 goto out;
918 }
919
920 switch (rt->dst.error) {
921 case EINVAL:
922 default:
923 goto out;
924 case EHOSTUNREACH:
925 code = ICMP_HOST_UNREACH;
926 break;
927 case ENETUNREACH:
928 code = ICMP_NET_UNREACH;
929 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
930 break;
931 case EACCES:
932 code = ICMP_PKT_FILTERED;
933 break;
934 }
935
936 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
937
938 send = true;
939 if (peer) {
940 now = jiffies;
941 peer->rate_tokens += now - peer->rate_last;
942 if (peer->rate_tokens > ip_rt_error_burst)
943 peer->rate_tokens = ip_rt_error_burst;
944 peer->rate_last = now;
945 if (peer->rate_tokens >= ip_rt_error_cost)
946 peer->rate_tokens -= ip_rt_error_cost;
947 else
948 send = false;
949 inet_putpeer(peer);
950 }
951 if (send)
952 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
953
954 out: kfree_skb(skb);
955 return 0;
956 }
957
958 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
959 {
960 struct dst_entry *dst = &rt->dst;
961 struct fib_result res;
962
963 if (dst_metric_locked(dst, RTAX_MTU))
964 return;
965
966 if (dst->dev->mtu < mtu)
967 return;
968
969 if (rt->rt_pmtu && rt->rt_pmtu < mtu)
970 return;
971
972 if (mtu < ip_rt_min_pmtu)
973 mtu = ip_rt_min_pmtu;
974
975 if (rt->rt_pmtu == mtu &&
976 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
977 return;
978
979 rcu_read_lock();
980 if (fib_lookup(dev_net(dst->dev), fl4, &res) == 0) {
981 struct fib_nh *nh = &FIB_RES_NH(res);
982
983 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
984 jiffies + ip_rt_mtu_expires);
985 }
986 rcu_read_unlock();
987 }
988
989 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
990 struct sk_buff *skb, u32 mtu)
991 {
992 struct rtable *rt = (struct rtable *) dst;
993 struct flowi4 fl4;
994
995 ip_rt_build_flow_key(&fl4, sk, skb);
996 __ip_rt_update_pmtu(rt, &fl4, mtu);
997 }
998
999 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1000 int oif, u32 mark, u8 protocol, int flow_flags)
1001 {
1002 const struct iphdr *iph = (const struct iphdr *) skb->data;
1003 struct flowi4 fl4;
1004 struct rtable *rt;
1005
1006 if (!mark)
1007 mark = IP4_REPLY_MARK(net, skb->mark);
1008
1009 __build_flow_key(&fl4, NULL, iph, oif,
1010 RT_TOS(iph->tos), protocol, mark, flow_flags);
1011 rt = __ip_route_output_key(net, &fl4);
1012 if (!IS_ERR(rt)) {
1013 __ip_rt_update_pmtu(rt, &fl4, mtu);
1014 ip_rt_put(rt);
1015 }
1016 }
1017 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1018
1019 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1020 {
1021 const struct iphdr *iph = (const struct iphdr *) skb->data;
1022 struct flowi4 fl4;
1023 struct rtable *rt;
1024
1025 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1026
1027 if (!fl4.flowi4_mark)
1028 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1029
1030 rt = __ip_route_output_key(sock_net(sk), &fl4);
1031 if (!IS_ERR(rt)) {
1032 __ip_rt_update_pmtu(rt, &fl4, mtu);
1033 ip_rt_put(rt);
1034 }
1035 }
1036
1037 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1038 {
1039 const struct iphdr *iph = (const struct iphdr *) skb->data;
1040 struct flowi4 fl4;
1041 struct rtable *rt;
1042 struct dst_entry *odst = NULL;
1043 bool new = false;
1044
1045 bh_lock_sock(sk);
1046
1047 if (!ip_sk_accept_pmtu(sk))
1048 goto out;
1049
1050 odst = sk_dst_get(sk);
1051
1052 if (sock_owned_by_user(sk) || !odst) {
1053 __ipv4_sk_update_pmtu(skb, sk, mtu);
1054 goto out;
1055 }
1056
1057 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1058
1059 rt = (struct rtable *)odst;
1060 if (odst->obsolete && odst->ops->check(odst, 0) == NULL) {
1061 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1062 if (IS_ERR(rt))
1063 goto out;
1064
1065 new = true;
1066 }
1067
1068 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1069
1070 if (!dst_check(&rt->dst, 0)) {
1071 if (new)
1072 dst_release(&rt->dst);
1073
1074 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1075 if (IS_ERR(rt))
1076 goto out;
1077
1078 new = true;
1079 }
1080
1081 if (new)
1082 sk_dst_set(sk, &rt->dst);
1083
1084 out:
1085 bh_unlock_sock(sk);
1086 dst_release(odst);
1087 }
1088 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1089
1090 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1091 int oif, u32 mark, u8 protocol, int flow_flags)
1092 {
1093 const struct iphdr *iph = (const struct iphdr *) skb->data;
1094 struct flowi4 fl4;
1095 struct rtable *rt;
1096
1097 __build_flow_key(&fl4, NULL, iph, oif,
1098 RT_TOS(iph->tos), protocol, mark, flow_flags);
1099 rt = __ip_route_output_key(net, &fl4);
1100 if (!IS_ERR(rt)) {
1101 __ip_do_redirect(rt, skb, &fl4, false);
1102 ip_rt_put(rt);
1103 }
1104 }
1105 EXPORT_SYMBOL_GPL(ipv4_redirect);
1106
1107 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1108 {
1109 const struct iphdr *iph = (const struct iphdr *) skb->data;
1110 struct flowi4 fl4;
1111 struct rtable *rt;
1112
1113 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1114 rt = __ip_route_output_key(sock_net(sk), &fl4);
1115 if (!IS_ERR(rt)) {
1116 __ip_do_redirect(rt, skb, &fl4, false);
1117 ip_rt_put(rt);
1118 }
1119 }
1120 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1121
1122 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1123 {
1124 struct rtable *rt = (struct rtable *) dst;
1125
1126 /* All IPV4 dsts are created with ->obsolete set to the value
1127 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1128 * into this function always.
1129 *
1130 * When a PMTU/redirect information update invalidates a route,
1131 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1132 * DST_OBSOLETE_DEAD by dst_free().
1133 */
1134 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1135 return NULL;
1136 return dst;
1137 }
1138
1139 static void ipv4_link_failure(struct sk_buff *skb)
1140 {
1141 struct rtable *rt;
1142
1143 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1144
1145 rt = skb_rtable(skb);
1146 if (rt)
1147 dst_set_expires(&rt->dst, 0);
1148 }
1149
1150 static int ip_rt_bug(struct sock *sk, struct sk_buff *skb)
1151 {
1152 pr_debug("%s: %pI4 -> %pI4, %s\n",
1153 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1154 skb->dev ? skb->dev->name : "?");
1155 kfree_skb(skb);
1156 WARN_ON(1);
1157 return 0;
1158 }
1159
1160 /*
1161 We do not cache source address of outgoing interface,
1162 because it is used only by IP RR, TS and SRR options,
1163 so that it out of fast path.
1164
1165 BTW remember: "addr" is allowed to be not aligned
1166 in IP options!
1167 */
1168
1169 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1170 {
1171 __be32 src;
1172
1173 if (rt_is_output_route(rt))
1174 src = ip_hdr(skb)->saddr;
1175 else {
1176 struct fib_result res;
1177 struct flowi4 fl4;
1178 struct iphdr *iph;
1179
1180 iph = ip_hdr(skb);
1181
1182 memset(&fl4, 0, sizeof(fl4));
1183 fl4.daddr = iph->daddr;
1184 fl4.saddr = iph->saddr;
1185 fl4.flowi4_tos = RT_TOS(iph->tos);
1186 fl4.flowi4_oif = rt->dst.dev->ifindex;
1187 fl4.flowi4_iif = skb->dev->ifindex;
1188 fl4.flowi4_mark = skb->mark;
1189
1190 rcu_read_lock();
1191 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1192 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1193 else
1194 src = inet_select_addr(rt->dst.dev,
1195 rt_nexthop(rt, iph->daddr),
1196 RT_SCOPE_UNIVERSE);
1197 rcu_read_unlock();
1198 }
1199 memcpy(addr, &src, 4);
1200 }
1201
1202 #ifdef CONFIG_IP_ROUTE_CLASSID
1203 static void set_class_tag(struct rtable *rt, u32 tag)
1204 {
1205 if (!(rt->dst.tclassid & 0xFFFF))
1206 rt->dst.tclassid |= tag & 0xFFFF;
1207 if (!(rt->dst.tclassid & 0xFFFF0000))
1208 rt->dst.tclassid |= tag & 0xFFFF0000;
1209 }
1210 #endif
1211
1212 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1213 {
1214 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1215
1216 if (advmss == 0) {
1217 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1218 ip_rt_min_advmss);
1219 if (advmss > 65535 - 40)
1220 advmss = 65535 - 40;
1221 }
1222 return advmss;
1223 }
1224
1225 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1226 {
1227 const struct rtable *rt = (const struct rtable *) dst;
1228 unsigned int mtu = rt->rt_pmtu;
1229
1230 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1231 mtu = dst_metric_raw(dst, RTAX_MTU);
1232
1233 if (mtu)
1234 return mtu;
1235
1236 mtu = dst->dev->mtu;
1237
1238 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1239 if (rt->rt_uses_gateway && mtu > 576)
1240 mtu = 576;
1241 }
1242
1243 return min_t(unsigned int, mtu, IP_MAX_MTU);
1244 }
1245
1246 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1247 {
1248 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1249 struct fib_nh_exception *fnhe;
1250 u32 hval;
1251
1252 if (!hash)
1253 return NULL;
1254
1255 hval = fnhe_hashfun(daddr);
1256
1257 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1258 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1259 if (fnhe->fnhe_daddr == daddr)
1260 return fnhe;
1261 }
1262 return NULL;
1263 }
1264
1265 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1266 __be32 daddr)
1267 {
1268 bool ret = false;
1269
1270 spin_lock_bh(&fnhe_lock);
1271
1272 if (daddr == fnhe->fnhe_daddr) {
1273 struct rtable __rcu **porig;
1274 struct rtable *orig;
1275 int genid = fnhe_genid(dev_net(rt->dst.dev));
1276
1277 if (rt_is_input_route(rt))
1278 porig = &fnhe->fnhe_rth_input;
1279 else
1280 porig = &fnhe->fnhe_rth_output;
1281 orig = rcu_dereference(*porig);
1282
1283 if (fnhe->fnhe_genid != genid) {
1284 fnhe->fnhe_genid = genid;
1285 fnhe->fnhe_gw = 0;
1286 fnhe->fnhe_pmtu = 0;
1287 fnhe->fnhe_expires = 0;
1288 fnhe_flush_routes(fnhe);
1289 orig = NULL;
1290 }
1291 fill_route_from_fnhe(rt, fnhe);
1292 if (!rt->rt_gateway)
1293 rt->rt_gateway = daddr;
1294
1295 if (!(rt->dst.flags & DST_NOCACHE)) {
1296 rcu_assign_pointer(*porig, rt);
1297 if (orig)
1298 rt_free(orig);
1299 ret = true;
1300 }
1301
1302 fnhe->fnhe_stamp = jiffies;
1303 }
1304 spin_unlock_bh(&fnhe_lock);
1305
1306 return ret;
1307 }
1308
1309 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1310 {
1311 struct rtable *orig, *prev, **p;
1312 bool ret = true;
1313
1314 if (rt_is_input_route(rt)) {
1315 p = (struct rtable **)&nh->nh_rth_input;
1316 } else {
1317 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1318 }
1319 orig = *p;
1320
1321 prev = cmpxchg(p, orig, rt);
1322 if (prev == orig) {
1323 if (orig)
1324 rt_free(orig);
1325 } else
1326 ret = false;
1327
1328 return ret;
1329 }
1330
1331 struct uncached_list {
1332 spinlock_t lock;
1333 struct list_head head;
1334 };
1335
1336 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1337
1338 static void rt_add_uncached_list(struct rtable *rt)
1339 {
1340 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1341
1342 rt->rt_uncached_list = ul;
1343
1344 spin_lock_bh(&ul->lock);
1345 list_add_tail(&rt->rt_uncached, &ul->head);
1346 spin_unlock_bh(&ul->lock);
1347 }
1348
1349 static void ipv4_dst_destroy(struct dst_entry *dst)
1350 {
1351 struct rtable *rt = (struct rtable *) dst;
1352
1353 if (!list_empty(&rt->rt_uncached)) {
1354 struct uncached_list *ul = rt->rt_uncached_list;
1355
1356 spin_lock_bh(&ul->lock);
1357 list_del(&rt->rt_uncached);
1358 spin_unlock_bh(&ul->lock);
1359 }
1360 }
1361
1362 void rt_flush_dev(struct net_device *dev)
1363 {
1364 struct net *net = dev_net(dev);
1365 struct rtable *rt;
1366 int cpu;
1367
1368 for_each_possible_cpu(cpu) {
1369 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1370
1371 spin_lock_bh(&ul->lock);
1372 list_for_each_entry(rt, &ul->head, rt_uncached) {
1373 if (rt->dst.dev != dev)
1374 continue;
1375 rt->dst.dev = net->loopback_dev;
1376 dev_hold(rt->dst.dev);
1377 dev_put(dev);
1378 }
1379 spin_unlock_bh(&ul->lock);
1380 }
1381 }
1382
1383 static bool rt_cache_valid(const struct rtable *rt)
1384 {
1385 return rt &&
1386 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1387 !rt_is_expired(rt);
1388 }
1389
1390 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1391 const struct fib_result *res,
1392 struct fib_nh_exception *fnhe,
1393 struct fib_info *fi, u16 type, u32 itag)
1394 {
1395 bool cached = false;
1396
1397 if (fi) {
1398 struct fib_nh *nh = &FIB_RES_NH(*res);
1399
1400 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1401 rt->rt_gateway = nh->nh_gw;
1402 rt->rt_uses_gateway = 1;
1403 }
1404 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1405 #ifdef CONFIG_IP_ROUTE_CLASSID
1406 rt->dst.tclassid = nh->nh_tclassid;
1407 #endif
1408 if (unlikely(fnhe))
1409 cached = rt_bind_exception(rt, fnhe, daddr);
1410 else if (!(rt->dst.flags & DST_NOCACHE))
1411 cached = rt_cache_route(nh, rt);
1412 if (unlikely(!cached)) {
1413 /* Routes we intend to cache in nexthop exception or
1414 * FIB nexthop have the DST_NOCACHE bit clear.
1415 * However, if we are unsuccessful at storing this
1416 * route into the cache we really need to set it.
1417 */
1418 rt->dst.flags |= DST_NOCACHE;
1419 if (!rt->rt_gateway)
1420 rt->rt_gateway = daddr;
1421 rt_add_uncached_list(rt);
1422 }
1423 } else
1424 rt_add_uncached_list(rt);
1425
1426 #ifdef CONFIG_IP_ROUTE_CLASSID
1427 #ifdef CONFIG_IP_MULTIPLE_TABLES
1428 set_class_tag(rt, res->tclassid);
1429 #endif
1430 set_class_tag(rt, itag);
1431 #endif
1432 }
1433
1434 static struct rtable *rt_dst_alloc(struct net_device *dev,
1435 bool nopolicy, bool noxfrm, bool will_cache)
1436 {
1437 return dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1438 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1439 (nopolicy ? DST_NOPOLICY : 0) |
1440 (noxfrm ? DST_NOXFRM : 0));
1441 }
1442
1443 /* called in rcu_read_lock() section */
1444 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1445 u8 tos, struct net_device *dev, int our)
1446 {
1447 struct rtable *rth;
1448 struct in_device *in_dev = __in_dev_get_rcu(dev);
1449 u32 itag = 0;
1450 int err;
1451
1452 /* Primary sanity checks. */
1453
1454 if (in_dev == NULL)
1455 return -EINVAL;
1456
1457 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1458 skb->protocol != htons(ETH_P_IP))
1459 goto e_inval;
1460
1461 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1462 if (ipv4_is_loopback(saddr))
1463 goto e_inval;
1464
1465 if (ipv4_is_zeronet(saddr)) {
1466 if (!ipv4_is_local_multicast(daddr))
1467 goto e_inval;
1468 } else {
1469 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1470 in_dev, &itag);
1471 if (err < 0)
1472 goto e_err;
1473 }
1474 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1475 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1476 if (!rth)
1477 goto e_nobufs;
1478
1479 #ifdef CONFIG_IP_ROUTE_CLASSID
1480 rth->dst.tclassid = itag;
1481 #endif
1482 rth->dst.output = ip_rt_bug;
1483
1484 rth->rt_genid = rt_genid_ipv4(dev_net(dev));
1485 rth->rt_flags = RTCF_MULTICAST;
1486 rth->rt_type = RTN_MULTICAST;
1487 rth->rt_is_input= 1;
1488 rth->rt_iif = 0;
1489 rth->rt_pmtu = 0;
1490 rth->rt_gateway = 0;
1491 rth->rt_uses_gateway = 0;
1492 INIT_LIST_HEAD(&rth->rt_uncached);
1493 if (our) {
1494 rth->dst.input= ip_local_deliver;
1495 rth->rt_flags |= RTCF_LOCAL;
1496 }
1497
1498 #ifdef CONFIG_IP_MROUTE
1499 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1500 rth->dst.input = ip_mr_input;
1501 #endif
1502 RT_CACHE_STAT_INC(in_slow_mc);
1503
1504 skb_dst_set(skb, &rth->dst);
1505 return 0;
1506
1507 e_nobufs:
1508 return -ENOBUFS;
1509 e_inval:
1510 return -EINVAL;
1511 e_err:
1512 return err;
1513 }
1514
1515
1516 static void ip_handle_martian_source(struct net_device *dev,
1517 struct in_device *in_dev,
1518 struct sk_buff *skb,
1519 __be32 daddr,
1520 __be32 saddr)
1521 {
1522 RT_CACHE_STAT_INC(in_martian_src);
1523 #ifdef CONFIG_IP_ROUTE_VERBOSE
1524 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1525 /*
1526 * RFC1812 recommendation, if source is martian,
1527 * the only hint is MAC header.
1528 */
1529 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1530 &daddr, &saddr, dev->name);
1531 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1532 print_hex_dump(KERN_WARNING, "ll header: ",
1533 DUMP_PREFIX_OFFSET, 16, 1,
1534 skb_mac_header(skb),
1535 dev->hard_header_len, true);
1536 }
1537 }
1538 #endif
1539 }
1540
1541 /* called in rcu_read_lock() section */
1542 static int __mkroute_input(struct sk_buff *skb,
1543 const struct fib_result *res,
1544 struct in_device *in_dev,
1545 __be32 daddr, __be32 saddr, u32 tos)
1546 {
1547 struct fib_nh_exception *fnhe;
1548 struct rtable *rth;
1549 int err;
1550 struct in_device *out_dev;
1551 unsigned int flags = 0;
1552 bool do_cache;
1553 u32 itag = 0;
1554
1555 /* get a working reference to the output device */
1556 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1557 if (out_dev == NULL) {
1558 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1559 return -EINVAL;
1560 }
1561
1562 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1563 in_dev->dev, in_dev, &itag);
1564 if (err < 0) {
1565 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1566 saddr);
1567
1568 goto cleanup;
1569 }
1570
1571 do_cache = res->fi && !itag;
1572 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1573 skb->protocol == htons(ETH_P_IP) &&
1574 (IN_DEV_SHARED_MEDIA(out_dev) ||
1575 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1576 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1577
1578 if (skb->protocol != htons(ETH_P_IP)) {
1579 /* Not IP (i.e. ARP). Do not create route, if it is
1580 * invalid for proxy arp. DNAT routes are always valid.
1581 *
1582 * Proxy arp feature have been extended to allow, ARP
1583 * replies back to the same interface, to support
1584 * Private VLAN switch technologies. See arp.c.
1585 */
1586 if (out_dev == in_dev &&
1587 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1588 err = -EINVAL;
1589 goto cleanup;
1590 }
1591 }
1592
1593 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1594 if (do_cache) {
1595 if (fnhe != NULL)
1596 rth = rcu_dereference(fnhe->fnhe_rth_input);
1597 else
1598 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1599
1600 if (rt_cache_valid(rth)) {
1601 skb_dst_set_noref(skb, &rth->dst);
1602 goto out;
1603 }
1604 }
1605
1606 rth = rt_dst_alloc(out_dev->dev,
1607 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1608 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1609 if (!rth) {
1610 err = -ENOBUFS;
1611 goto cleanup;
1612 }
1613
1614 rth->rt_genid = rt_genid_ipv4(dev_net(rth->dst.dev));
1615 rth->rt_flags = flags;
1616 rth->rt_type = res->type;
1617 rth->rt_is_input = 1;
1618 rth->rt_iif = 0;
1619 rth->rt_pmtu = 0;
1620 rth->rt_gateway = 0;
1621 rth->rt_uses_gateway = 0;
1622 INIT_LIST_HEAD(&rth->rt_uncached);
1623 RT_CACHE_STAT_INC(in_slow_tot);
1624
1625 rth->dst.input = ip_forward;
1626 rth->dst.output = ip_output;
1627
1628 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1629 skb_dst_set(skb, &rth->dst);
1630 out:
1631 err = 0;
1632 cleanup:
1633 return err;
1634 }
1635
1636 static int ip_mkroute_input(struct sk_buff *skb,
1637 struct fib_result *res,
1638 const struct flowi4 *fl4,
1639 struct in_device *in_dev,
1640 __be32 daddr, __be32 saddr, u32 tos)
1641 {
1642 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1643 if (res->fi && res->fi->fib_nhs > 1)
1644 fib_select_multipath(res);
1645 #endif
1646
1647 /* create a routing cache entry */
1648 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1649 }
1650
1651 /*
1652 * NOTE. We drop all the packets that has local source
1653 * addresses, because every properly looped back packet
1654 * must have correct destination already attached by output routine.
1655 *
1656 * Such approach solves two big problems:
1657 * 1. Not simplex devices are handled properly.
1658 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1659 * called with rcu_read_lock()
1660 */
1661
1662 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1663 u8 tos, struct net_device *dev)
1664 {
1665 struct fib_result res;
1666 struct in_device *in_dev = __in_dev_get_rcu(dev);
1667 struct flowi4 fl4;
1668 unsigned int flags = 0;
1669 u32 itag = 0;
1670 struct rtable *rth;
1671 int err = -EINVAL;
1672 struct net *net = dev_net(dev);
1673 bool do_cache;
1674
1675 /* IP on this device is disabled. */
1676
1677 if (!in_dev)
1678 goto out;
1679
1680 /* Check for the most weird martians, which can be not detected
1681 by fib_lookup.
1682 */
1683
1684 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1685 goto martian_source;
1686
1687 res.fi = NULL;
1688 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1689 goto brd_input;
1690
1691 /* Accept zero addresses only to limited broadcast;
1692 * I even do not know to fix it or not. Waiting for complains :-)
1693 */
1694 if (ipv4_is_zeronet(saddr))
1695 goto martian_source;
1696
1697 if (ipv4_is_zeronet(daddr))
1698 goto martian_destination;
1699
1700 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1701 * and call it once if daddr or/and saddr are loopback addresses
1702 */
1703 if (ipv4_is_loopback(daddr)) {
1704 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1705 goto martian_destination;
1706 } else if (ipv4_is_loopback(saddr)) {
1707 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1708 goto martian_source;
1709 }
1710
1711 /*
1712 * Now we are ready to route packet.
1713 */
1714 fl4.flowi4_oif = 0;
1715 fl4.flowi4_iif = dev->ifindex;
1716 fl4.flowi4_mark = skb->mark;
1717 fl4.flowi4_tos = tos;
1718 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1719 fl4.daddr = daddr;
1720 fl4.saddr = saddr;
1721 err = fib_lookup(net, &fl4, &res);
1722 if (err != 0) {
1723 if (!IN_DEV_FORWARD(in_dev))
1724 err = -EHOSTUNREACH;
1725 goto no_route;
1726 }
1727
1728 if (res.type == RTN_BROADCAST)
1729 goto brd_input;
1730
1731 if (res.type == RTN_LOCAL) {
1732 err = fib_validate_source(skb, saddr, daddr, tos,
1733 0, dev, in_dev, &itag);
1734 if (err < 0)
1735 goto martian_source_keep_err;
1736 goto local_input;
1737 }
1738
1739 if (!IN_DEV_FORWARD(in_dev)) {
1740 err = -EHOSTUNREACH;
1741 goto no_route;
1742 }
1743 if (res.type != RTN_UNICAST)
1744 goto martian_destination;
1745
1746 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1747 out: return err;
1748
1749 brd_input:
1750 if (skb->protocol != htons(ETH_P_IP))
1751 goto e_inval;
1752
1753 if (!ipv4_is_zeronet(saddr)) {
1754 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1755 in_dev, &itag);
1756 if (err < 0)
1757 goto martian_source_keep_err;
1758 }
1759 flags |= RTCF_BROADCAST;
1760 res.type = RTN_BROADCAST;
1761 RT_CACHE_STAT_INC(in_brd);
1762
1763 local_input:
1764 do_cache = false;
1765 if (res.fi) {
1766 if (!itag) {
1767 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1768 if (rt_cache_valid(rth)) {
1769 skb_dst_set_noref(skb, &rth->dst);
1770 err = 0;
1771 goto out;
1772 }
1773 do_cache = true;
1774 }
1775 }
1776
1777 rth = rt_dst_alloc(net->loopback_dev,
1778 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1779 if (!rth)
1780 goto e_nobufs;
1781
1782 rth->dst.input= ip_local_deliver;
1783 rth->dst.output= ip_rt_bug;
1784 #ifdef CONFIG_IP_ROUTE_CLASSID
1785 rth->dst.tclassid = itag;
1786 #endif
1787
1788 rth->rt_genid = rt_genid_ipv4(net);
1789 rth->rt_flags = flags|RTCF_LOCAL;
1790 rth->rt_type = res.type;
1791 rth->rt_is_input = 1;
1792 rth->rt_iif = 0;
1793 rth->rt_pmtu = 0;
1794 rth->rt_gateway = 0;
1795 rth->rt_uses_gateway = 0;
1796 INIT_LIST_HEAD(&rth->rt_uncached);
1797 RT_CACHE_STAT_INC(in_slow_tot);
1798 if (res.type == RTN_UNREACHABLE) {
1799 rth->dst.input= ip_error;
1800 rth->dst.error= -err;
1801 rth->rt_flags &= ~RTCF_LOCAL;
1802 }
1803 if (do_cache) {
1804 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
1805 rth->dst.flags |= DST_NOCACHE;
1806 rt_add_uncached_list(rth);
1807 }
1808 }
1809 skb_dst_set(skb, &rth->dst);
1810 err = 0;
1811 goto out;
1812
1813 no_route:
1814 RT_CACHE_STAT_INC(in_no_route);
1815 res.type = RTN_UNREACHABLE;
1816 res.fi = NULL;
1817 goto local_input;
1818
1819 /*
1820 * Do not cache martian addresses: they should be logged (RFC1812)
1821 */
1822 martian_destination:
1823 RT_CACHE_STAT_INC(in_martian_dst);
1824 #ifdef CONFIG_IP_ROUTE_VERBOSE
1825 if (IN_DEV_LOG_MARTIANS(in_dev))
1826 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1827 &daddr, &saddr, dev->name);
1828 #endif
1829
1830 e_inval:
1831 err = -EINVAL;
1832 goto out;
1833
1834 e_nobufs:
1835 err = -ENOBUFS;
1836 goto out;
1837
1838 martian_source:
1839 err = -EINVAL;
1840 martian_source_keep_err:
1841 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1842 goto out;
1843 }
1844
1845 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1846 u8 tos, struct net_device *dev)
1847 {
1848 int res;
1849
1850 rcu_read_lock();
1851
1852 /* Multicast recognition logic is moved from route cache to here.
1853 The problem was that too many Ethernet cards have broken/missing
1854 hardware multicast filters :-( As result the host on multicasting
1855 network acquires a lot of useless route cache entries, sort of
1856 SDR messages from all the world. Now we try to get rid of them.
1857 Really, provided software IP multicast filter is organized
1858 reasonably (at least, hashed), it does not result in a slowdown
1859 comparing with route cache reject entries.
1860 Note, that multicast routers are not affected, because
1861 route cache entry is created eventually.
1862 */
1863 if (ipv4_is_multicast(daddr)) {
1864 struct in_device *in_dev = __in_dev_get_rcu(dev);
1865
1866 if (in_dev) {
1867 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1868 ip_hdr(skb)->protocol);
1869 if (our
1870 #ifdef CONFIG_IP_MROUTE
1871 ||
1872 (!ipv4_is_local_multicast(daddr) &&
1873 IN_DEV_MFORWARD(in_dev))
1874 #endif
1875 ) {
1876 int res = ip_route_input_mc(skb, daddr, saddr,
1877 tos, dev, our);
1878 rcu_read_unlock();
1879 return res;
1880 }
1881 }
1882 rcu_read_unlock();
1883 return -EINVAL;
1884 }
1885 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1886 rcu_read_unlock();
1887 return res;
1888 }
1889 EXPORT_SYMBOL(ip_route_input_noref);
1890
1891 /* called with rcu_read_lock() */
1892 static struct rtable *__mkroute_output(const struct fib_result *res,
1893 const struct flowi4 *fl4, int orig_oif,
1894 struct net_device *dev_out,
1895 unsigned int flags)
1896 {
1897 struct fib_info *fi = res->fi;
1898 struct fib_nh_exception *fnhe;
1899 struct in_device *in_dev;
1900 u16 type = res->type;
1901 struct rtable *rth;
1902 bool do_cache;
1903
1904 in_dev = __in_dev_get_rcu(dev_out);
1905 if (!in_dev)
1906 return ERR_PTR(-EINVAL);
1907
1908 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1909 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
1910 return ERR_PTR(-EINVAL);
1911
1912 if (ipv4_is_lbcast(fl4->daddr))
1913 type = RTN_BROADCAST;
1914 else if (ipv4_is_multicast(fl4->daddr))
1915 type = RTN_MULTICAST;
1916 else if (ipv4_is_zeronet(fl4->daddr))
1917 return ERR_PTR(-EINVAL);
1918
1919 if (dev_out->flags & IFF_LOOPBACK)
1920 flags |= RTCF_LOCAL;
1921
1922 do_cache = true;
1923 if (type == RTN_BROADCAST) {
1924 flags |= RTCF_BROADCAST | RTCF_LOCAL;
1925 fi = NULL;
1926 } else if (type == RTN_MULTICAST) {
1927 flags |= RTCF_MULTICAST | RTCF_LOCAL;
1928 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
1929 fl4->flowi4_proto))
1930 flags &= ~RTCF_LOCAL;
1931 else
1932 do_cache = false;
1933 /* If multicast route do not exist use
1934 * default one, but do not gateway in this case.
1935 * Yes, it is hack.
1936 */
1937 if (fi && res->prefixlen < 4)
1938 fi = NULL;
1939 }
1940
1941 fnhe = NULL;
1942 do_cache &= fi != NULL;
1943 if (do_cache) {
1944 struct rtable __rcu **prth;
1945 struct fib_nh *nh = &FIB_RES_NH(*res);
1946
1947 fnhe = find_exception(nh, fl4->daddr);
1948 if (fnhe)
1949 prth = &fnhe->fnhe_rth_output;
1950 else {
1951 if (unlikely(fl4->flowi4_flags &
1952 FLOWI_FLAG_KNOWN_NH &&
1953 !(nh->nh_gw &&
1954 nh->nh_scope == RT_SCOPE_LINK))) {
1955 do_cache = false;
1956 goto add;
1957 }
1958 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
1959 }
1960 rth = rcu_dereference(*prth);
1961 if (rt_cache_valid(rth)) {
1962 dst_hold(&rth->dst);
1963 return rth;
1964 }
1965 }
1966
1967 add:
1968 rth = rt_dst_alloc(dev_out,
1969 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1970 IN_DEV_CONF_GET(in_dev, NOXFRM),
1971 do_cache);
1972 if (!rth)
1973 return ERR_PTR(-ENOBUFS);
1974
1975 rth->dst.output = ip_output;
1976
1977 rth->rt_genid = rt_genid_ipv4(dev_net(dev_out));
1978 rth->rt_flags = flags;
1979 rth->rt_type = type;
1980 rth->rt_is_input = 0;
1981 rth->rt_iif = orig_oif ? : 0;
1982 rth->rt_pmtu = 0;
1983 rth->rt_gateway = 0;
1984 rth->rt_uses_gateway = 0;
1985 INIT_LIST_HEAD(&rth->rt_uncached);
1986
1987 RT_CACHE_STAT_INC(out_slow_tot);
1988
1989 if (flags & RTCF_LOCAL)
1990 rth->dst.input = ip_local_deliver;
1991 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1992 if (flags & RTCF_LOCAL &&
1993 !(dev_out->flags & IFF_LOOPBACK)) {
1994 rth->dst.output = ip_mc_output;
1995 RT_CACHE_STAT_INC(out_slow_mc);
1996 }
1997 #ifdef CONFIG_IP_MROUTE
1998 if (type == RTN_MULTICAST) {
1999 if (IN_DEV_MFORWARD(in_dev) &&
2000 !ipv4_is_local_multicast(fl4->daddr)) {
2001 rth->dst.input = ip_mr_input;
2002 rth->dst.output = ip_mc_output;
2003 }
2004 }
2005 #endif
2006 }
2007
2008 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2009
2010 return rth;
2011 }
2012
2013 /*
2014 * Major route resolver routine.
2015 */
2016
2017 struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
2018 {
2019 struct net_device *dev_out = NULL;
2020 __u8 tos = RT_FL_TOS(fl4);
2021 unsigned int flags = 0;
2022 struct fib_result res;
2023 struct rtable *rth;
2024 int orig_oif;
2025
2026 res.tclassid = 0;
2027 res.fi = NULL;
2028 res.table = NULL;
2029
2030 orig_oif = fl4->flowi4_oif;
2031
2032 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2033 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2034 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2035 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2036
2037 rcu_read_lock();
2038 if (fl4->saddr) {
2039 rth = ERR_PTR(-EINVAL);
2040 if (ipv4_is_multicast(fl4->saddr) ||
2041 ipv4_is_lbcast(fl4->saddr) ||
2042 ipv4_is_zeronet(fl4->saddr))
2043 goto out;
2044
2045 /* I removed check for oif == dev_out->oif here.
2046 It was wrong for two reasons:
2047 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2048 is assigned to multiple interfaces.
2049 2. Moreover, we are allowed to send packets with saddr
2050 of another iface. --ANK
2051 */
2052
2053 if (fl4->flowi4_oif == 0 &&
2054 (ipv4_is_multicast(fl4->daddr) ||
2055 ipv4_is_lbcast(fl4->daddr))) {
2056 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2057 dev_out = __ip_dev_find(net, fl4->saddr, false);
2058 if (dev_out == NULL)
2059 goto out;
2060
2061 /* Special hack: user can direct multicasts
2062 and limited broadcast via necessary interface
2063 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2064 This hack is not just for fun, it allows
2065 vic,vat and friends to work.
2066 They bind socket to loopback, set ttl to zero
2067 and expect that it will work.
2068 From the viewpoint of routing cache they are broken,
2069 because we are not allowed to build multicast path
2070 with loopback source addr (look, routing cache
2071 cannot know, that ttl is zero, so that packet
2072 will not leave this host and route is valid).
2073 Luckily, this hack is good workaround.
2074 */
2075
2076 fl4->flowi4_oif = dev_out->ifindex;
2077 goto make_route;
2078 }
2079
2080 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2081 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2082 if (!__ip_dev_find(net, fl4->saddr, false))
2083 goto out;
2084 }
2085 }
2086
2087
2088 if (fl4->flowi4_oif) {
2089 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2090 rth = ERR_PTR(-ENODEV);
2091 if (dev_out == NULL)
2092 goto out;
2093
2094 /* RACE: Check return value of inet_select_addr instead. */
2095 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2096 rth = ERR_PTR(-ENETUNREACH);
2097 goto out;
2098 }
2099 if (ipv4_is_local_multicast(fl4->daddr) ||
2100 ipv4_is_lbcast(fl4->daddr)) {
2101 if (!fl4->saddr)
2102 fl4->saddr = inet_select_addr(dev_out, 0,
2103 RT_SCOPE_LINK);
2104 goto make_route;
2105 }
2106 if (!fl4->saddr) {
2107 if (ipv4_is_multicast(fl4->daddr))
2108 fl4->saddr = inet_select_addr(dev_out, 0,
2109 fl4->flowi4_scope);
2110 else if (!fl4->daddr)
2111 fl4->saddr = inet_select_addr(dev_out, 0,
2112 RT_SCOPE_HOST);
2113 }
2114 }
2115
2116 if (!fl4->daddr) {
2117 fl4->daddr = fl4->saddr;
2118 if (!fl4->daddr)
2119 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2120 dev_out = net->loopback_dev;
2121 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2122 res.type = RTN_LOCAL;
2123 flags |= RTCF_LOCAL;
2124 goto make_route;
2125 }
2126
2127 if (fib_lookup(net, fl4, &res)) {
2128 res.fi = NULL;
2129 res.table = NULL;
2130 if (fl4->flowi4_oif) {
2131 /* Apparently, routing tables are wrong. Assume,
2132 that the destination is on link.
2133
2134 WHY? DW.
2135 Because we are allowed to send to iface
2136 even if it has NO routes and NO assigned
2137 addresses. When oif is specified, routing
2138 tables are looked up with only one purpose:
2139 to catch if destination is gatewayed, rather than
2140 direct. Moreover, if MSG_DONTROUTE is set,
2141 we send packet, ignoring both routing tables
2142 and ifaddr state. --ANK
2143
2144
2145 We could make it even if oif is unknown,
2146 likely IPv6, but we do not.
2147 */
2148
2149 if (fl4->saddr == 0)
2150 fl4->saddr = inet_select_addr(dev_out, 0,
2151 RT_SCOPE_LINK);
2152 res.type = RTN_UNICAST;
2153 goto make_route;
2154 }
2155 rth = ERR_PTR(-ENETUNREACH);
2156 goto out;
2157 }
2158
2159 if (res.type == RTN_LOCAL) {
2160 if (!fl4->saddr) {
2161 if (res.fi->fib_prefsrc)
2162 fl4->saddr = res.fi->fib_prefsrc;
2163 else
2164 fl4->saddr = fl4->daddr;
2165 }
2166 dev_out = net->loopback_dev;
2167 fl4->flowi4_oif = dev_out->ifindex;
2168 flags |= RTCF_LOCAL;
2169 goto make_route;
2170 }
2171
2172 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2173 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2174 fib_select_multipath(&res);
2175 else
2176 #endif
2177 if (!res.prefixlen &&
2178 res.table->tb_num_default > 1 &&
2179 res.type == RTN_UNICAST && !fl4->flowi4_oif)
2180 fib_select_default(&res);
2181
2182 if (!fl4->saddr)
2183 fl4->saddr = FIB_RES_PREFSRC(net, res);
2184
2185 dev_out = FIB_RES_DEV(res);
2186 fl4->flowi4_oif = dev_out->ifindex;
2187
2188
2189 make_route:
2190 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2191
2192 out:
2193 rcu_read_unlock();
2194 return rth;
2195 }
2196 EXPORT_SYMBOL_GPL(__ip_route_output_key);
2197
2198 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2199 {
2200 return NULL;
2201 }
2202
2203 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2204 {
2205 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2206
2207 return mtu ? : dst->dev->mtu;
2208 }
2209
2210 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2211 struct sk_buff *skb, u32 mtu)
2212 {
2213 }
2214
2215 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2216 struct sk_buff *skb)
2217 {
2218 }
2219
2220 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2221 unsigned long old)
2222 {
2223 return NULL;
2224 }
2225
2226 static struct dst_ops ipv4_dst_blackhole_ops = {
2227 .family = AF_INET,
2228 .protocol = cpu_to_be16(ETH_P_IP),
2229 .check = ipv4_blackhole_dst_check,
2230 .mtu = ipv4_blackhole_mtu,
2231 .default_advmss = ipv4_default_advmss,
2232 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2233 .redirect = ipv4_rt_blackhole_redirect,
2234 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2235 .neigh_lookup = ipv4_neigh_lookup,
2236 };
2237
2238 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2239 {
2240 struct rtable *ort = (struct rtable *) dst_orig;
2241 struct rtable *rt;
2242
2243 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2244 if (rt) {
2245 struct dst_entry *new = &rt->dst;
2246
2247 new->__use = 1;
2248 new->input = dst_discard;
2249 new->output = dst_discard_sk;
2250
2251 new->dev = ort->dst.dev;
2252 if (new->dev)
2253 dev_hold(new->dev);
2254
2255 rt->rt_is_input = ort->rt_is_input;
2256 rt->rt_iif = ort->rt_iif;
2257 rt->rt_pmtu = ort->rt_pmtu;
2258
2259 rt->rt_genid = rt_genid_ipv4(net);
2260 rt->rt_flags = ort->rt_flags;
2261 rt->rt_type = ort->rt_type;
2262 rt->rt_gateway = ort->rt_gateway;
2263 rt->rt_uses_gateway = ort->rt_uses_gateway;
2264
2265 INIT_LIST_HEAD(&rt->rt_uncached);
2266
2267 dst_free(new);
2268 }
2269
2270 dst_release(dst_orig);
2271
2272 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2273 }
2274
2275 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2276 struct sock *sk)
2277 {
2278 struct rtable *rt = __ip_route_output_key(net, flp4);
2279
2280 if (IS_ERR(rt))
2281 return rt;
2282
2283 if (flp4->flowi4_proto)
2284 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2285 flowi4_to_flowi(flp4),
2286 sk, 0);
2287
2288 return rt;
2289 }
2290 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2291
2292 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2293 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2294 u32 seq, int event, int nowait, unsigned int flags)
2295 {
2296 struct rtable *rt = skb_rtable(skb);
2297 struct rtmsg *r;
2298 struct nlmsghdr *nlh;
2299 unsigned long expires = 0;
2300 u32 error;
2301 u32 metrics[RTAX_MAX];
2302
2303 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2304 if (nlh == NULL)
2305 return -EMSGSIZE;
2306
2307 r = nlmsg_data(nlh);
2308 r->rtm_family = AF_INET;
2309 r->rtm_dst_len = 32;
2310 r->rtm_src_len = 0;
2311 r->rtm_tos = fl4->flowi4_tos;
2312 r->rtm_table = RT_TABLE_MAIN;
2313 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2314 goto nla_put_failure;
2315 r->rtm_type = rt->rt_type;
2316 r->rtm_scope = RT_SCOPE_UNIVERSE;
2317 r->rtm_protocol = RTPROT_UNSPEC;
2318 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2319 if (rt->rt_flags & RTCF_NOTIFY)
2320 r->rtm_flags |= RTM_F_NOTIFY;
2321 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2322 r->rtm_flags |= RTCF_DOREDIRECT;
2323
2324 if (nla_put_be32(skb, RTA_DST, dst))
2325 goto nla_put_failure;
2326 if (src) {
2327 r->rtm_src_len = 32;
2328 if (nla_put_be32(skb, RTA_SRC, src))
2329 goto nla_put_failure;
2330 }
2331 if (rt->dst.dev &&
2332 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2333 goto nla_put_failure;
2334 #ifdef CONFIG_IP_ROUTE_CLASSID
2335 if (rt->dst.tclassid &&
2336 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2337 goto nla_put_failure;
2338 #endif
2339 if (!rt_is_input_route(rt) &&
2340 fl4->saddr != src) {
2341 if (nla_put_be32(skb, RTA_PREFSRC, fl4->saddr))
2342 goto nla_put_failure;
2343 }
2344 if (rt->rt_uses_gateway &&
2345 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2346 goto nla_put_failure;
2347
2348 expires = rt->dst.expires;
2349 if (expires) {
2350 unsigned long now = jiffies;
2351
2352 if (time_before(now, expires))
2353 expires -= now;
2354 else
2355 expires = 0;
2356 }
2357
2358 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2359 if (rt->rt_pmtu && expires)
2360 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2361 if (rtnetlink_put_metrics(skb, metrics) < 0)
2362 goto nla_put_failure;
2363
2364 if (fl4->flowi4_mark &&
2365 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2366 goto nla_put_failure;
2367
2368 error = rt->dst.error;
2369
2370 if (rt_is_input_route(rt)) {
2371 #ifdef CONFIG_IP_MROUTE
2372 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2373 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2374 int err = ipmr_get_route(net, skb,
2375 fl4->saddr, fl4->daddr,
2376 r, nowait);
2377 if (err <= 0) {
2378 if (!nowait) {
2379 if (err == 0)
2380 return 0;
2381 goto nla_put_failure;
2382 } else {
2383 if (err == -EMSGSIZE)
2384 goto nla_put_failure;
2385 error = err;
2386 }
2387 }
2388 } else
2389 #endif
2390 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2391 goto nla_put_failure;
2392 }
2393
2394 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2395 goto nla_put_failure;
2396
2397 nlmsg_end(skb, nlh);
2398 return 0;
2399
2400 nla_put_failure:
2401 nlmsg_cancel(skb, nlh);
2402 return -EMSGSIZE;
2403 }
2404
2405 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2406 {
2407 struct net *net = sock_net(in_skb->sk);
2408 struct rtmsg *rtm;
2409 struct nlattr *tb[RTA_MAX+1];
2410 struct rtable *rt = NULL;
2411 struct flowi4 fl4;
2412 __be32 dst = 0;
2413 __be32 src = 0;
2414 u32 iif;
2415 int err;
2416 int mark;
2417 struct sk_buff *skb;
2418
2419 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2420 if (err < 0)
2421 goto errout;
2422
2423 rtm = nlmsg_data(nlh);
2424
2425 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2426 if (skb == NULL) {
2427 err = -ENOBUFS;
2428 goto errout;
2429 }
2430
2431 /* Reserve room for dummy headers, this skb can pass
2432 through good chunk of routing engine.
2433 */
2434 skb_reset_mac_header(skb);
2435 skb_reset_network_header(skb);
2436
2437 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2438 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2439 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2440
2441 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2442 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2443 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2444 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2445
2446 memset(&fl4, 0, sizeof(fl4));
2447 fl4.daddr = dst;
2448 fl4.saddr = src;
2449 fl4.flowi4_tos = rtm->rtm_tos;
2450 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2451 fl4.flowi4_mark = mark;
2452
2453 if (iif) {
2454 struct net_device *dev;
2455
2456 dev = __dev_get_by_index(net, iif);
2457 if (dev == NULL) {
2458 err = -ENODEV;
2459 goto errout_free;
2460 }
2461
2462 skb->protocol = htons(ETH_P_IP);
2463 skb->dev = dev;
2464 skb->mark = mark;
2465 local_bh_disable();
2466 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2467 local_bh_enable();
2468
2469 rt = skb_rtable(skb);
2470 if (err == 0 && rt->dst.error)
2471 err = -rt->dst.error;
2472 } else {
2473 rt = ip_route_output_key(net, &fl4);
2474
2475 err = 0;
2476 if (IS_ERR(rt))
2477 err = PTR_ERR(rt);
2478 }
2479
2480 if (err)
2481 goto errout_free;
2482
2483 skb_dst_set(skb, &rt->dst);
2484 if (rtm->rtm_flags & RTM_F_NOTIFY)
2485 rt->rt_flags |= RTCF_NOTIFY;
2486
2487 err = rt_fill_info(net, dst, src, &fl4, skb,
2488 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2489 RTM_NEWROUTE, 0, 0);
2490 if (err < 0)
2491 goto errout_free;
2492
2493 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2494 errout:
2495 return err;
2496
2497 errout_free:
2498 kfree_skb(skb);
2499 goto errout;
2500 }
2501
2502 void ip_rt_multicast_event(struct in_device *in_dev)
2503 {
2504 rt_cache_flush(dev_net(in_dev->dev));
2505 }
2506
2507 #ifdef CONFIG_SYSCTL
2508 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
2509 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2510 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2511 static int ip_rt_gc_elasticity __read_mostly = 8;
2512
2513 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2514 void __user *buffer,
2515 size_t *lenp, loff_t *ppos)
2516 {
2517 struct net *net = (struct net *)__ctl->extra1;
2518
2519 if (write) {
2520 rt_cache_flush(net);
2521 fnhe_genid_bump(net);
2522 return 0;
2523 }
2524
2525 return -EINVAL;
2526 }
2527
2528 static struct ctl_table ipv4_route_table[] = {
2529 {
2530 .procname = "gc_thresh",
2531 .data = &ipv4_dst_ops.gc_thresh,
2532 .maxlen = sizeof(int),
2533 .mode = 0644,
2534 .proc_handler = proc_dointvec,
2535 },
2536 {
2537 .procname = "max_size",
2538 .data = &ip_rt_max_size,
2539 .maxlen = sizeof(int),
2540 .mode = 0644,
2541 .proc_handler = proc_dointvec,
2542 },
2543 {
2544 /* Deprecated. Use gc_min_interval_ms */
2545
2546 .procname = "gc_min_interval",
2547 .data = &ip_rt_gc_min_interval,
2548 .maxlen = sizeof(int),
2549 .mode = 0644,
2550 .proc_handler = proc_dointvec_jiffies,
2551 },
2552 {
2553 .procname = "gc_min_interval_ms",
2554 .data = &ip_rt_gc_min_interval,
2555 .maxlen = sizeof(int),
2556 .mode = 0644,
2557 .proc_handler = proc_dointvec_ms_jiffies,
2558 },
2559 {
2560 .procname = "gc_timeout",
2561 .data = &ip_rt_gc_timeout,
2562 .maxlen = sizeof(int),
2563 .mode = 0644,
2564 .proc_handler = proc_dointvec_jiffies,
2565 },
2566 {
2567 .procname = "gc_interval",
2568 .data = &ip_rt_gc_interval,
2569 .maxlen = sizeof(int),
2570 .mode = 0644,
2571 .proc_handler = proc_dointvec_jiffies,
2572 },
2573 {
2574 .procname = "redirect_load",
2575 .data = &ip_rt_redirect_load,
2576 .maxlen = sizeof(int),
2577 .mode = 0644,
2578 .proc_handler = proc_dointvec,
2579 },
2580 {
2581 .procname = "redirect_number",
2582 .data = &ip_rt_redirect_number,
2583 .maxlen = sizeof(int),
2584 .mode = 0644,
2585 .proc_handler = proc_dointvec,
2586 },
2587 {
2588 .procname = "redirect_silence",
2589 .data = &ip_rt_redirect_silence,
2590 .maxlen = sizeof(int),
2591 .mode = 0644,
2592 .proc_handler = proc_dointvec,
2593 },
2594 {
2595 .procname = "error_cost",
2596 .data = &ip_rt_error_cost,
2597 .maxlen = sizeof(int),
2598 .mode = 0644,
2599 .proc_handler = proc_dointvec,
2600 },
2601 {
2602 .procname = "error_burst",
2603 .data = &ip_rt_error_burst,
2604 .maxlen = sizeof(int),
2605 .mode = 0644,
2606 .proc_handler = proc_dointvec,
2607 },
2608 {
2609 .procname = "gc_elasticity",
2610 .data = &ip_rt_gc_elasticity,
2611 .maxlen = sizeof(int),
2612 .mode = 0644,
2613 .proc_handler = proc_dointvec,
2614 },
2615 {
2616 .procname = "mtu_expires",
2617 .data = &ip_rt_mtu_expires,
2618 .maxlen = sizeof(int),
2619 .mode = 0644,
2620 .proc_handler = proc_dointvec_jiffies,
2621 },
2622 {
2623 .procname = "min_pmtu",
2624 .data = &ip_rt_min_pmtu,
2625 .maxlen = sizeof(int),
2626 .mode = 0644,
2627 .proc_handler = proc_dointvec,
2628 },
2629 {
2630 .procname = "min_adv_mss",
2631 .data = &ip_rt_min_advmss,
2632 .maxlen = sizeof(int),
2633 .mode = 0644,
2634 .proc_handler = proc_dointvec,
2635 },
2636 { }
2637 };
2638
2639 static struct ctl_table ipv4_route_flush_table[] = {
2640 {
2641 .procname = "flush",
2642 .maxlen = sizeof(int),
2643 .mode = 0200,
2644 .proc_handler = ipv4_sysctl_rtcache_flush,
2645 },
2646 { },
2647 };
2648
2649 static __net_init int sysctl_route_net_init(struct net *net)
2650 {
2651 struct ctl_table *tbl;
2652
2653 tbl = ipv4_route_flush_table;
2654 if (!net_eq(net, &init_net)) {
2655 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2656 if (tbl == NULL)
2657 goto err_dup;
2658
2659 /* Don't export sysctls to unprivileged users */
2660 if (net->user_ns != &init_user_ns)
2661 tbl[0].procname = NULL;
2662 }
2663 tbl[0].extra1 = net;
2664
2665 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2666 if (net->ipv4.route_hdr == NULL)
2667 goto err_reg;
2668 return 0;
2669
2670 err_reg:
2671 if (tbl != ipv4_route_flush_table)
2672 kfree(tbl);
2673 err_dup:
2674 return -ENOMEM;
2675 }
2676
2677 static __net_exit void sysctl_route_net_exit(struct net *net)
2678 {
2679 struct ctl_table *tbl;
2680
2681 tbl = net->ipv4.route_hdr->ctl_table_arg;
2682 unregister_net_sysctl_table(net->ipv4.route_hdr);
2683 BUG_ON(tbl == ipv4_route_flush_table);
2684 kfree(tbl);
2685 }
2686
2687 static __net_initdata struct pernet_operations sysctl_route_ops = {
2688 .init = sysctl_route_net_init,
2689 .exit = sysctl_route_net_exit,
2690 };
2691 #endif
2692
2693 static __net_init int rt_genid_init(struct net *net)
2694 {
2695 atomic_set(&net->ipv4.rt_genid, 0);
2696 atomic_set(&net->fnhe_genid, 0);
2697 get_random_bytes(&net->ipv4.dev_addr_genid,
2698 sizeof(net->ipv4.dev_addr_genid));
2699 return 0;
2700 }
2701
2702 static __net_initdata struct pernet_operations rt_genid_ops = {
2703 .init = rt_genid_init,
2704 };
2705
2706 static int __net_init ipv4_inetpeer_init(struct net *net)
2707 {
2708 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2709
2710 if (!bp)
2711 return -ENOMEM;
2712 inet_peer_base_init(bp);
2713 net->ipv4.peers = bp;
2714 return 0;
2715 }
2716
2717 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2718 {
2719 struct inet_peer_base *bp = net->ipv4.peers;
2720
2721 net->ipv4.peers = NULL;
2722 inetpeer_invalidate_tree(bp);
2723 kfree(bp);
2724 }
2725
2726 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2727 .init = ipv4_inetpeer_init,
2728 .exit = ipv4_inetpeer_exit,
2729 };
2730
2731 #ifdef CONFIG_IP_ROUTE_CLASSID
2732 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2733 #endif /* CONFIG_IP_ROUTE_CLASSID */
2734
2735 int __init ip_rt_init(void)
2736 {
2737 int rc = 0;
2738 int cpu;
2739
2740 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2741 if (!ip_idents)
2742 panic("IP: failed to allocate ip_idents\n");
2743
2744 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2745
2746 for_each_possible_cpu(cpu) {
2747 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2748
2749 INIT_LIST_HEAD(&ul->head);
2750 spin_lock_init(&ul->lock);
2751 }
2752 #ifdef CONFIG_IP_ROUTE_CLASSID
2753 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2754 if (!ip_rt_acct)
2755 panic("IP: failed to allocate ip_rt_acct\n");
2756 #endif
2757
2758 ipv4_dst_ops.kmem_cachep =
2759 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2760 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2761
2762 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2763
2764 if (dst_entries_init(&ipv4_dst_ops) < 0)
2765 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2766
2767 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2768 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2769
2770 ipv4_dst_ops.gc_thresh = ~0;
2771 ip_rt_max_size = INT_MAX;
2772
2773 devinet_init();
2774 ip_fib_init();
2775
2776 if (ip_rt_proc_init())
2777 pr_err("Unable to create route proc files\n");
2778 #ifdef CONFIG_XFRM
2779 xfrm_init();
2780 xfrm4_init();
2781 #endif
2782 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2783
2784 #ifdef CONFIG_SYSCTL
2785 register_pernet_subsys(&sysctl_route_ops);
2786 #endif
2787 register_pernet_subsys(&rt_genid_ops);
2788 register_pernet_subsys(&ipv4_inetpeer_ops);
2789 return rc;
2790 }
2791
2792 #ifdef CONFIG_SYSCTL
2793 /*
2794 * We really need to sanitize the damn ipv4 init order, then all
2795 * this nonsense will go away.
2796 */
2797 void __init ip_static_sysctl_init(void)
2798 {
2799 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2800 }
2801 #endif
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