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[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/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 delta = 0;
480
481 if (old != now && cmpxchg(p_tstamp, old, now) == old)
482 delta = prandom_u32_max(now - old);
483
484 return atomic_add_return(segs + delta, p_id) - segs;
485 }
486 EXPORT_SYMBOL(ip_idents_reserve);
487
488 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
489 {
490 static u32 ip_idents_hashrnd __read_mostly;
491 u32 hash, id;
492
493 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
494
495 hash = jhash_3words((__force u32)iph->daddr,
496 (__force u32)iph->saddr,
497 iph->protocol ^ net_hash_mix(net),
498 ip_idents_hashrnd);
499 id = ip_idents_reserve(hash, segs);
500 iph->id = htons(id);
501 }
502 EXPORT_SYMBOL(__ip_select_ident);
503
504 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
505 const struct iphdr *iph,
506 int oif, u8 tos,
507 u8 prot, u32 mark, int flow_flags)
508 {
509 if (sk) {
510 const struct inet_sock *inet = inet_sk(sk);
511
512 oif = sk->sk_bound_dev_if;
513 mark = sk->sk_mark;
514 tos = RT_CONN_FLAGS(sk);
515 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
516 }
517 flowi4_init_output(fl4, oif, mark, tos,
518 RT_SCOPE_UNIVERSE, prot,
519 flow_flags,
520 iph->daddr, iph->saddr, 0, 0);
521 }
522
523 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
524 const struct sock *sk)
525 {
526 const struct iphdr *iph = ip_hdr(skb);
527 int oif = skb->dev->ifindex;
528 u8 tos = RT_TOS(iph->tos);
529 u8 prot = iph->protocol;
530 u32 mark = skb->mark;
531
532 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
533 }
534
535 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
536 {
537 const struct inet_sock *inet = inet_sk(sk);
538 const struct ip_options_rcu *inet_opt;
539 __be32 daddr = inet->inet_daddr;
540
541 rcu_read_lock();
542 inet_opt = rcu_dereference(inet->inet_opt);
543 if (inet_opt && inet_opt->opt.srr)
544 daddr = inet_opt->opt.faddr;
545 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
546 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
547 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
548 inet_sk_flowi_flags(sk),
549 daddr, inet->inet_saddr, 0, 0);
550 rcu_read_unlock();
551 }
552
553 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
554 const struct sk_buff *skb)
555 {
556 if (skb)
557 build_skb_flow_key(fl4, skb, sk);
558 else
559 build_sk_flow_key(fl4, sk);
560 }
561
562 static inline void rt_free(struct rtable *rt)
563 {
564 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
565 }
566
567 static DEFINE_SPINLOCK(fnhe_lock);
568
569 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
570 {
571 struct rtable *rt;
572
573 rt = rcu_dereference(fnhe->fnhe_rth_input);
574 if (rt) {
575 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
576 rt_free(rt);
577 }
578 rt = rcu_dereference(fnhe->fnhe_rth_output);
579 if (rt) {
580 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
581 rt_free(rt);
582 }
583 }
584
585 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
586 {
587 struct fib_nh_exception *fnhe, *oldest;
588
589 oldest = rcu_dereference(hash->chain);
590 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
591 fnhe = rcu_dereference(fnhe->fnhe_next)) {
592 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
593 oldest = fnhe;
594 }
595 fnhe_flush_routes(oldest);
596 return oldest;
597 }
598
599 static inline u32 fnhe_hashfun(__be32 daddr)
600 {
601 static u32 fnhe_hashrnd __read_mostly;
602 u32 hval;
603
604 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
605 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
606 return hash_32(hval, FNHE_HASH_SHIFT);
607 }
608
609 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
610 {
611 rt->rt_pmtu = fnhe->fnhe_pmtu;
612 rt->dst.expires = fnhe->fnhe_expires;
613
614 if (fnhe->fnhe_gw) {
615 rt->rt_flags |= RTCF_REDIRECTED;
616 rt->rt_gateway = fnhe->fnhe_gw;
617 rt->rt_uses_gateway = 1;
618 }
619 }
620
621 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
622 u32 pmtu, unsigned long expires)
623 {
624 struct fnhe_hash_bucket *hash;
625 struct fib_nh_exception *fnhe;
626 struct rtable *rt;
627 unsigned int i;
628 int depth;
629 u32 hval = fnhe_hashfun(daddr);
630
631 spin_lock_bh(&fnhe_lock);
632
633 hash = rcu_dereference(nh->nh_exceptions);
634 if (!hash) {
635 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
636 if (!hash)
637 goto out_unlock;
638 rcu_assign_pointer(nh->nh_exceptions, hash);
639 }
640
641 hash += hval;
642
643 depth = 0;
644 for (fnhe = rcu_dereference(hash->chain); fnhe;
645 fnhe = rcu_dereference(fnhe->fnhe_next)) {
646 if (fnhe->fnhe_daddr == daddr)
647 break;
648 depth++;
649 }
650
651 if (fnhe) {
652 if (gw)
653 fnhe->fnhe_gw = gw;
654 if (pmtu) {
655 fnhe->fnhe_pmtu = pmtu;
656 fnhe->fnhe_expires = max(1UL, expires);
657 }
658 /* Update all cached dsts too */
659 rt = rcu_dereference(fnhe->fnhe_rth_input);
660 if (rt)
661 fill_route_from_fnhe(rt, fnhe);
662 rt = rcu_dereference(fnhe->fnhe_rth_output);
663 if (rt)
664 fill_route_from_fnhe(rt, fnhe);
665 } else {
666 if (depth > FNHE_RECLAIM_DEPTH)
667 fnhe = fnhe_oldest(hash);
668 else {
669 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
670 if (!fnhe)
671 goto out_unlock;
672
673 fnhe->fnhe_next = hash->chain;
674 rcu_assign_pointer(hash->chain, fnhe);
675 }
676 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
677 fnhe->fnhe_daddr = daddr;
678 fnhe->fnhe_gw = gw;
679 fnhe->fnhe_pmtu = pmtu;
680 fnhe->fnhe_expires = expires;
681
682 /* Exception created; mark the cached routes for the nexthop
683 * stale, so anyone caching it rechecks if this exception
684 * applies to them.
685 */
686 rt = rcu_dereference(nh->nh_rth_input);
687 if (rt)
688 rt->dst.obsolete = DST_OBSOLETE_KILL;
689
690 for_each_possible_cpu(i) {
691 struct rtable __rcu **prt;
692 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
693 rt = rcu_dereference(*prt);
694 if (rt)
695 rt->dst.obsolete = DST_OBSOLETE_KILL;
696 }
697 }
698
699 fnhe->fnhe_stamp = jiffies;
700
701 out_unlock:
702 spin_unlock_bh(&fnhe_lock);
703 }
704
705 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
706 bool kill_route)
707 {
708 __be32 new_gw = icmp_hdr(skb)->un.gateway;
709 __be32 old_gw = ip_hdr(skb)->saddr;
710 struct net_device *dev = skb->dev;
711 struct in_device *in_dev;
712 struct fib_result res;
713 struct neighbour *n;
714 struct net *net;
715
716 switch (icmp_hdr(skb)->code & 7) {
717 case ICMP_REDIR_NET:
718 case ICMP_REDIR_NETTOS:
719 case ICMP_REDIR_HOST:
720 case ICMP_REDIR_HOSTTOS:
721 break;
722
723 default:
724 return;
725 }
726
727 if (rt->rt_gateway != old_gw)
728 return;
729
730 in_dev = __in_dev_get_rcu(dev);
731 if (!in_dev)
732 return;
733
734 net = dev_net(dev);
735 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
736 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
737 ipv4_is_zeronet(new_gw))
738 goto reject_redirect;
739
740 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
741 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
742 goto reject_redirect;
743 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
744 goto reject_redirect;
745 } else {
746 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
747 goto reject_redirect;
748 }
749
750 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
751 if (!IS_ERR(n)) {
752 if (!(n->nud_state & NUD_VALID)) {
753 neigh_event_send(n, NULL);
754 } else {
755 if (fib_lookup(net, fl4, &res, 0) == 0) {
756 struct fib_nh *nh = &FIB_RES_NH(res);
757
758 update_or_create_fnhe(nh, fl4->daddr, new_gw,
759 0, jiffies + ip_rt_gc_timeout);
760 }
761 if (kill_route)
762 rt->dst.obsolete = DST_OBSOLETE_KILL;
763 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
764 }
765 neigh_release(n);
766 }
767 return;
768
769 reject_redirect:
770 #ifdef CONFIG_IP_ROUTE_VERBOSE
771 if (IN_DEV_LOG_MARTIANS(in_dev)) {
772 const struct iphdr *iph = (const struct iphdr *) skb->data;
773 __be32 daddr = iph->daddr;
774 __be32 saddr = iph->saddr;
775
776 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
777 " Advised path = %pI4 -> %pI4\n",
778 &old_gw, dev->name, &new_gw,
779 &saddr, &daddr);
780 }
781 #endif
782 ;
783 }
784
785 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
786 {
787 struct rtable *rt;
788 struct flowi4 fl4;
789 const struct iphdr *iph = (const struct iphdr *) skb->data;
790 int oif = skb->dev->ifindex;
791 u8 tos = RT_TOS(iph->tos);
792 u8 prot = iph->protocol;
793 u32 mark = skb->mark;
794
795 rt = (struct rtable *) dst;
796
797 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
798 __ip_do_redirect(rt, skb, &fl4, true);
799 }
800
801 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
802 {
803 struct rtable *rt = (struct rtable *)dst;
804 struct dst_entry *ret = dst;
805
806 if (rt) {
807 if (dst->obsolete > 0) {
808 ip_rt_put(rt);
809 ret = NULL;
810 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
811 rt->dst.expires) {
812 ip_rt_put(rt);
813 ret = NULL;
814 }
815 }
816 return ret;
817 }
818
819 /*
820 * Algorithm:
821 * 1. The first ip_rt_redirect_number redirects are sent
822 * with exponential backoff, then we stop sending them at all,
823 * assuming that the host ignores our redirects.
824 * 2. If we did not see packets requiring redirects
825 * during ip_rt_redirect_silence, we assume that the host
826 * forgot redirected route and start to send redirects again.
827 *
828 * This algorithm is much cheaper and more intelligent than dumb load limiting
829 * in icmp.c.
830 *
831 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
832 * and "frag. need" (breaks PMTU discovery) in icmp.c.
833 */
834
835 void ip_rt_send_redirect(struct sk_buff *skb)
836 {
837 struct rtable *rt = skb_rtable(skb);
838 struct in_device *in_dev;
839 struct inet_peer *peer;
840 struct net *net;
841 int log_martians;
842 int vif;
843
844 rcu_read_lock();
845 in_dev = __in_dev_get_rcu(rt->dst.dev);
846 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
847 rcu_read_unlock();
848 return;
849 }
850 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
851 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
852 rcu_read_unlock();
853
854 net = dev_net(rt->dst.dev);
855 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
856 if (!peer) {
857 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
858 rt_nexthop(rt, ip_hdr(skb)->daddr));
859 return;
860 }
861
862 /* No redirected packets during ip_rt_redirect_silence;
863 * reset the algorithm.
864 */
865 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
866 peer->rate_tokens = 0;
867
868 /* Too many ignored redirects; do not send anything
869 * set dst.rate_last to the last seen redirected packet.
870 */
871 if (peer->rate_tokens >= ip_rt_redirect_number) {
872 peer->rate_last = jiffies;
873 goto out_put_peer;
874 }
875
876 /* Check for load limit; set rate_last to the latest sent
877 * redirect.
878 */
879 if (peer->rate_tokens == 0 ||
880 time_after(jiffies,
881 (peer->rate_last +
882 (ip_rt_redirect_load << peer->rate_tokens)))) {
883 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
884
885 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
886 peer->rate_last = jiffies;
887 ++peer->rate_tokens;
888 #ifdef CONFIG_IP_ROUTE_VERBOSE
889 if (log_martians &&
890 peer->rate_tokens == ip_rt_redirect_number)
891 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
892 &ip_hdr(skb)->saddr, inet_iif(skb),
893 &ip_hdr(skb)->daddr, &gw);
894 #endif
895 }
896 out_put_peer:
897 inet_putpeer(peer);
898 }
899
900 static int ip_error(struct sk_buff *skb)
901 {
902 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
903 struct rtable *rt = skb_rtable(skb);
904 struct inet_peer *peer;
905 unsigned long now;
906 struct net *net;
907 bool send;
908 int code;
909
910 /* IP on this device is disabled. */
911 if (!in_dev)
912 goto out;
913
914 net = dev_net(rt->dst.dev);
915 if (!IN_DEV_FORWARD(in_dev)) {
916 switch (rt->dst.error) {
917 case EHOSTUNREACH:
918 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
919 break;
920
921 case ENETUNREACH:
922 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
923 break;
924 }
925 goto out;
926 }
927
928 switch (rt->dst.error) {
929 case EINVAL:
930 default:
931 goto out;
932 case EHOSTUNREACH:
933 code = ICMP_HOST_UNREACH;
934 break;
935 case ENETUNREACH:
936 code = ICMP_NET_UNREACH;
937 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
938 break;
939 case EACCES:
940 code = ICMP_PKT_FILTERED;
941 break;
942 }
943
944 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
945 l3mdev_master_ifindex(skb->dev), 1);
946
947 send = true;
948 if (peer) {
949 now = jiffies;
950 peer->rate_tokens += now - peer->rate_last;
951 if (peer->rate_tokens > ip_rt_error_burst)
952 peer->rate_tokens = ip_rt_error_burst;
953 peer->rate_last = now;
954 if (peer->rate_tokens >= ip_rt_error_cost)
955 peer->rate_tokens -= ip_rt_error_cost;
956 else
957 send = false;
958 inet_putpeer(peer);
959 }
960 if (send)
961 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
962
963 out: kfree_skb(skb);
964 return 0;
965 }
966
967 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
968 {
969 struct dst_entry *dst = &rt->dst;
970 struct fib_result res;
971
972 if (dst_metric_locked(dst, RTAX_MTU))
973 return;
974
975 if (ipv4_mtu(dst) < mtu)
976 return;
977
978 if (mtu < ip_rt_min_pmtu)
979 mtu = ip_rt_min_pmtu;
980
981 if (rt->rt_pmtu == mtu &&
982 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
983 return;
984
985 rcu_read_lock();
986 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
987 struct fib_nh *nh = &FIB_RES_NH(res);
988
989 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
990 jiffies + ip_rt_mtu_expires);
991 }
992 rcu_read_unlock();
993 }
994
995 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
996 struct sk_buff *skb, u32 mtu)
997 {
998 struct rtable *rt = (struct rtable *) dst;
999 struct flowi4 fl4;
1000
1001 ip_rt_build_flow_key(&fl4, sk, skb);
1002 __ip_rt_update_pmtu(rt, &fl4, mtu);
1003 }
1004
1005 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1006 int oif, u32 mark, u8 protocol, int flow_flags)
1007 {
1008 const struct iphdr *iph = (const struct iphdr *) skb->data;
1009 struct flowi4 fl4;
1010 struct rtable *rt;
1011
1012 if (!mark)
1013 mark = IP4_REPLY_MARK(net, skb->mark);
1014
1015 __build_flow_key(&fl4, NULL, iph, oif,
1016 RT_TOS(iph->tos), protocol, mark, flow_flags);
1017 rt = __ip_route_output_key(net, &fl4);
1018 if (!IS_ERR(rt)) {
1019 __ip_rt_update_pmtu(rt, &fl4, mtu);
1020 ip_rt_put(rt);
1021 }
1022 }
1023 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1024
1025 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1026 {
1027 const struct iphdr *iph = (const struct iphdr *) skb->data;
1028 struct flowi4 fl4;
1029 struct rtable *rt;
1030
1031 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1032
1033 if (!fl4.flowi4_mark)
1034 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1035
1036 rt = __ip_route_output_key(sock_net(sk), &fl4);
1037 if (!IS_ERR(rt)) {
1038 __ip_rt_update_pmtu(rt, &fl4, mtu);
1039 ip_rt_put(rt);
1040 }
1041 }
1042
1043 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1044 {
1045 const struct iphdr *iph = (const struct iphdr *) skb->data;
1046 struct flowi4 fl4;
1047 struct rtable *rt;
1048 struct dst_entry *odst = NULL;
1049 bool new = false;
1050
1051 bh_lock_sock(sk);
1052
1053 if (!ip_sk_accept_pmtu(sk))
1054 goto out;
1055
1056 odst = sk_dst_get(sk);
1057
1058 if (sock_owned_by_user(sk) || !odst) {
1059 __ipv4_sk_update_pmtu(skb, sk, mtu);
1060 goto out;
1061 }
1062
1063 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1064
1065 rt = (struct rtable *)odst;
1066 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1067 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1068 if (IS_ERR(rt))
1069 goto out;
1070
1071 new = true;
1072 }
1073
1074 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1075
1076 if (!dst_check(&rt->dst, 0)) {
1077 if (new)
1078 dst_release(&rt->dst);
1079
1080 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1081 if (IS_ERR(rt))
1082 goto out;
1083
1084 new = true;
1085 }
1086
1087 if (new)
1088 sk_dst_set(sk, &rt->dst);
1089
1090 out:
1091 bh_unlock_sock(sk);
1092 dst_release(odst);
1093 }
1094 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1095
1096 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1097 int oif, u32 mark, u8 protocol, int flow_flags)
1098 {
1099 const struct iphdr *iph = (const struct iphdr *) skb->data;
1100 struct flowi4 fl4;
1101 struct rtable *rt;
1102
1103 __build_flow_key(&fl4, NULL, iph, oif,
1104 RT_TOS(iph->tos), protocol, mark, flow_flags);
1105 rt = __ip_route_output_key(net, &fl4);
1106 if (!IS_ERR(rt)) {
1107 __ip_do_redirect(rt, skb, &fl4, false);
1108 ip_rt_put(rt);
1109 }
1110 }
1111 EXPORT_SYMBOL_GPL(ipv4_redirect);
1112
1113 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1114 {
1115 const struct iphdr *iph = (const struct iphdr *) skb->data;
1116 struct flowi4 fl4;
1117 struct rtable *rt;
1118
1119 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1120 rt = __ip_route_output_key(sock_net(sk), &fl4);
1121 if (!IS_ERR(rt)) {
1122 __ip_do_redirect(rt, skb, &fl4, false);
1123 ip_rt_put(rt);
1124 }
1125 }
1126 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1127
1128 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1129 {
1130 struct rtable *rt = (struct rtable *) dst;
1131
1132 /* All IPV4 dsts are created with ->obsolete set to the value
1133 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1134 * into this function always.
1135 *
1136 * When a PMTU/redirect information update invalidates a route,
1137 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1138 * DST_OBSOLETE_DEAD by dst_free().
1139 */
1140 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1141 return NULL;
1142 return dst;
1143 }
1144
1145 static void ipv4_link_failure(struct sk_buff *skb)
1146 {
1147 struct rtable *rt;
1148
1149 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1150
1151 rt = skb_rtable(skb);
1152 if (rt)
1153 dst_set_expires(&rt->dst, 0);
1154 }
1155
1156 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1157 {
1158 pr_debug("%s: %pI4 -> %pI4, %s\n",
1159 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1160 skb->dev ? skb->dev->name : "?");
1161 kfree_skb(skb);
1162 WARN_ON(1);
1163 return 0;
1164 }
1165
1166 /*
1167 We do not cache source address of outgoing interface,
1168 because it is used only by IP RR, TS and SRR options,
1169 so that it out of fast path.
1170
1171 BTW remember: "addr" is allowed to be not aligned
1172 in IP options!
1173 */
1174
1175 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1176 {
1177 __be32 src;
1178
1179 if (rt_is_output_route(rt))
1180 src = ip_hdr(skb)->saddr;
1181 else {
1182 struct fib_result res;
1183 struct flowi4 fl4;
1184 struct iphdr *iph;
1185
1186 iph = ip_hdr(skb);
1187
1188 memset(&fl4, 0, sizeof(fl4));
1189 fl4.daddr = iph->daddr;
1190 fl4.saddr = iph->saddr;
1191 fl4.flowi4_tos = RT_TOS(iph->tos);
1192 fl4.flowi4_oif = rt->dst.dev->ifindex;
1193 fl4.flowi4_iif = skb->dev->ifindex;
1194 fl4.flowi4_mark = skb->mark;
1195
1196 rcu_read_lock();
1197 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1198 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1199 else
1200 src = inet_select_addr(rt->dst.dev,
1201 rt_nexthop(rt, iph->daddr),
1202 RT_SCOPE_UNIVERSE);
1203 rcu_read_unlock();
1204 }
1205 memcpy(addr, &src, 4);
1206 }
1207
1208 #ifdef CONFIG_IP_ROUTE_CLASSID
1209 static void set_class_tag(struct rtable *rt, u32 tag)
1210 {
1211 if (!(rt->dst.tclassid & 0xFFFF))
1212 rt->dst.tclassid |= tag & 0xFFFF;
1213 if (!(rt->dst.tclassid & 0xFFFF0000))
1214 rt->dst.tclassid |= tag & 0xFFFF0000;
1215 }
1216 #endif
1217
1218 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1219 {
1220 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1221
1222 if (advmss == 0) {
1223 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1224 ip_rt_min_advmss);
1225 if (advmss > 65535 - 40)
1226 advmss = 65535 - 40;
1227 }
1228 return advmss;
1229 }
1230
1231 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1232 {
1233 const struct rtable *rt = (const struct rtable *) dst;
1234 unsigned int mtu = rt->rt_pmtu;
1235
1236 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1237 mtu = dst_metric_raw(dst, RTAX_MTU);
1238
1239 if (mtu)
1240 return mtu;
1241
1242 mtu = dst->dev->mtu;
1243
1244 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1245 if (rt->rt_uses_gateway && mtu > 576)
1246 mtu = 576;
1247 }
1248
1249 return min_t(unsigned int, mtu, IP_MAX_MTU);
1250 }
1251
1252 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1253 {
1254 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1255 struct fib_nh_exception *fnhe;
1256 u32 hval;
1257
1258 if (!hash)
1259 return NULL;
1260
1261 hval = fnhe_hashfun(daddr);
1262
1263 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1264 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1265 if (fnhe->fnhe_daddr == daddr)
1266 return fnhe;
1267 }
1268 return NULL;
1269 }
1270
1271 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1272 __be32 daddr)
1273 {
1274 bool ret = false;
1275
1276 spin_lock_bh(&fnhe_lock);
1277
1278 if (daddr == fnhe->fnhe_daddr) {
1279 struct rtable __rcu **porig;
1280 struct rtable *orig;
1281 int genid = fnhe_genid(dev_net(rt->dst.dev));
1282
1283 if (rt_is_input_route(rt))
1284 porig = &fnhe->fnhe_rth_input;
1285 else
1286 porig = &fnhe->fnhe_rth_output;
1287 orig = rcu_dereference(*porig);
1288
1289 if (fnhe->fnhe_genid != genid) {
1290 fnhe->fnhe_genid = genid;
1291 fnhe->fnhe_gw = 0;
1292 fnhe->fnhe_pmtu = 0;
1293 fnhe->fnhe_expires = 0;
1294 fnhe_flush_routes(fnhe);
1295 orig = NULL;
1296 }
1297 fill_route_from_fnhe(rt, fnhe);
1298 if (!rt->rt_gateway)
1299 rt->rt_gateway = daddr;
1300
1301 if (!(rt->dst.flags & DST_NOCACHE)) {
1302 rcu_assign_pointer(*porig, rt);
1303 if (orig)
1304 rt_free(orig);
1305 ret = true;
1306 }
1307
1308 fnhe->fnhe_stamp = jiffies;
1309 }
1310 spin_unlock_bh(&fnhe_lock);
1311
1312 return ret;
1313 }
1314
1315 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1316 {
1317 struct rtable *orig, *prev, **p;
1318 bool ret = true;
1319
1320 if (rt_is_input_route(rt)) {
1321 p = (struct rtable **)&nh->nh_rth_input;
1322 } else {
1323 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1324 }
1325 orig = *p;
1326
1327 prev = cmpxchg(p, orig, rt);
1328 if (prev == orig) {
1329 if (orig)
1330 rt_free(orig);
1331 } else
1332 ret = false;
1333
1334 return ret;
1335 }
1336
1337 struct uncached_list {
1338 spinlock_t lock;
1339 struct list_head head;
1340 };
1341
1342 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1343
1344 static void rt_add_uncached_list(struct rtable *rt)
1345 {
1346 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1347
1348 rt->rt_uncached_list = ul;
1349
1350 spin_lock_bh(&ul->lock);
1351 list_add_tail(&rt->rt_uncached, &ul->head);
1352 spin_unlock_bh(&ul->lock);
1353 }
1354
1355 static void ipv4_dst_destroy(struct dst_entry *dst)
1356 {
1357 struct rtable *rt = (struct rtable *) dst;
1358
1359 if (!list_empty(&rt->rt_uncached)) {
1360 struct uncached_list *ul = rt->rt_uncached_list;
1361
1362 spin_lock_bh(&ul->lock);
1363 list_del(&rt->rt_uncached);
1364 spin_unlock_bh(&ul->lock);
1365 }
1366 }
1367
1368 void rt_flush_dev(struct net_device *dev)
1369 {
1370 struct net *net = dev_net(dev);
1371 struct rtable *rt;
1372 int cpu;
1373
1374 for_each_possible_cpu(cpu) {
1375 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1376
1377 spin_lock_bh(&ul->lock);
1378 list_for_each_entry(rt, &ul->head, rt_uncached) {
1379 if (rt->dst.dev != dev)
1380 continue;
1381 rt->dst.dev = net->loopback_dev;
1382 dev_hold(rt->dst.dev);
1383 dev_put(dev);
1384 }
1385 spin_unlock_bh(&ul->lock);
1386 }
1387 }
1388
1389 static bool rt_cache_valid(const struct rtable *rt)
1390 {
1391 return rt &&
1392 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1393 !rt_is_expired(rt);
1394 }
1395
1396 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1397 const struct fib_result *res,
1398 struct fib_nh_exception *fnhe,
1399 struct fib_info *fi, u16 type, u32 itag)
1400 {
1401 bool cached = false;
1402
1403 if (fi) {
1404 struct fib_nh *nh = &FIB_RES_NH(*res);
1405
1406 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1407 rt->rt_gateway = nh->nh_gw;
1408 rt->rt_uses_gateway = 1;
1409 }
1410 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1411 #ifdef CONFIG_IP_ROUTE_CLASSID
1412 rt->dst.tclassid = nh->nh_tclassid;
1413 #endif
1414 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1415 if (unlikely(fnhe))
1416 cached = rt_bind_exception(rt, fnhe, daddr);
1417 else if (!(rt->dst.flags & DST_NOCACHE))
1418 cached = rt_cache_route(nh, rt);
1419 if (unlikely(!cached)) {
1420 /* Routes we intend to cache in nexthop exception or
1421 * FIB nexthop have the DST_NOCACHE bit clear.
1422 * However, if we are unsuccessful at storing this
1423 * route into the cache we really need to set it.
1424 */
1425 rt->dst.flags |= DST_NOCACHE;
1426 if (!rt->rt_gateway)
1427 rt->rt_gateway = daddr;
1428 rt_add_uncached_list(rt);
1429 }
1430 } else
1431 rt_add_uncached_list(rt);
1432
1433 #ifdef CONFIG_IP_ROUTE_CLASSID
1434 #ifdef CONFIG_IP_MULTIPLE_TABLES
1435 set_class_tag(rt, res->tclassid);
1436 #endif
1437 set_class_tag(rt, itag);
1438 #endif
1439 }
1440
1441 struct rtable *rt_dst_alloc(struct net_device *dev,
1442 unsigned int flags, u16 type,
1443 bool nopolicy, bool noxfrm, bool will_cache)
1444 {
1445 struct rtable *rt;
1446
1447 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1448 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1449 (nopolicy ? DST_NOPOLICY : 0) |
1450 (noxfrm ? DST_NOXFRM : 0));
1451
1452 if (rt) {
1453 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1454 rt->rt_flags = flags;
1455 rt->rt_type = type;
1456 rt->rt_is_input = 0;
1457 rt->rt_iif = 0;
1458 rt->rt_pmtu = 0;
1459 rt->rt_gateway = 0;
1460 rt->rt_uses_gateway = 0;
1461 rt->rt_table_id = 0;
1462 INIT_LIST_HEAD(&rt->rt_uncached);
1463
1464 rt->dst.output = ip_output;
1465 if (flags & RTCF_LOCAL)
1466 rt->dst.input = ip_local_deliver;
1467 }
1468
1469 return rt;
1470 }
1471 EXPORT_SYMBOL(rt_dst_alloc);
1472
1473 /* called in rcu_read_lock() section */
1474 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1475 u8 tos, struct net_device *dev, int our)
1476 {
1477 struct rtable *rth;
1478 struct in_device *in_dev = __in_dev_get_rcu(dev);
1479 unsigned int flags = RTCF_MULTICAST;
1480 u32 itag = 0;
1481 int err;
1482
1483 /* Primary sanity checks. */
1484
1485 if (!in_dev)
1486 return -EINVAL;
1487
1488 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1489 skb->protocol != htons(ETH_P_IP))
1490 goto e_inval;
1491
1492 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1493 goto e_inval;
1494
1495 if (ipv4_is_zeronet(saddr)) {
1496 if (!ipv4_is_local_multicast(daddr))
1497 goto e_inval;
1498 } else {
1499 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1500 in_dev, &itag);
1501 if (err < 0)
1502 goto e_err;
1503 }
1504 if (our)
1505 flags |= RTCF_LOCAL;
1506
1507 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1508 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1509 if (!rth)
1510 goto e_nobufs;
1511
1512 #ifdef CONFIG_IP_ROUTE_CLASSID
1513 rth->dst.tclassid = itag;
1514 #endif
1515 rth->dst.output = ip_rt_bug;
1516 rth->rt_is_input= 1;
1517
1518 #ifdef CONFIG_IP_MROUTE
1519 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1520 rth->dst.input = ip_mr_input;
1521 #endif
1522 RT_CACHE_STAT_INC(in_slow_mc);
1523
1524 skb_dst_set(skb, &rth->dst);
1525 return 0;
1526
1527 e_nobufs:
1528 return -ENOBUFS;
1529 e_inval:
1530 return -EINVAL;
1531 e_err:
1532 return err;
1533 }
1534
1535
1536 static void ip_handle_martian_source(struct net_device *dev,
1537 struct in_device *in_dev,
1538 struct sk_buff *skb,
1539 __be32 daddr,
1540 __be32 saddr)
1541 {
1542 RT_CACHE_STAT_INC(in_martian_src);
1543 #ifdef CONFIG_IP_ROUTE_VERBOSE
1544 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1545 /*
1546 * RFC1812 recommendation, if source is martian,
1547 * the only hint is MAC header.
1548 */
1549 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1550 &daddr, &saddr, dev->name);
1551 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1552 print_hex_dump(KERN_WARNING, "ll header: ",
1553 DUMP_PREFIX_OFFSET, 16, 1,
1554 skb_mac_header(skb),
1555 dev->hard_header_len, true);
1556 }
1557 }
1558 #endif
1559 }
1560
1561 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1562 {
1563 struct fnhe_hash_bucket *hash;
1564 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1565 u32 hval = fnhe_hashfun(daddr);
1566
1567 spin_lock_bh(&fnhe_lock);
1568
1569 hash = rcu_dereference_protected(nh->nh_exceptions,
1570 lockdep_is_held(&fnhe_lock));
1571 hash += hval;
1572
1573 fnhe_p = &hash->chain;
1574 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1575 while (fnhe) {
1576 if (fnhe->fnhe_daddr == daddr) {
1577 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1578 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1579 fnhe_flush_routes(fnhe);
1580 kfree_rcu(fnhe, rcu);
1581 break;
1582 }
1583 fnhe_p = &fnhe->fnhe_next;
1584 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1585 lockdep_is_held(&fnhe_lock));
1586 }
1587
1588 spin_unlock_bh(&fnhe_lock);
1589 }
1590
1591 /* called in rcu_read_lock() section */
1592 static int __mkroute_input(struct sk_buff *skb,
1593 const struct fib_result *res,
1594 struct in_device *in_dev,
1595 __be32 daddr, __be32 saddr, u32 tos)
1596 {
1597 struct fib_nh_exception *fnhe;
1598 struct rtable *rth;
1599 int err;
1600 struct in_device *out_dev;
1601 bool do_cache;
1602 u32 itag = 0;
1603
1604 /* get a working reference to the output device */
1605 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1606 if (!out_dev) {
1607 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1608 return -EINVAL;
1609 }
1610
1611 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1612 in_dev->dev, in_dev, &itag);
1613 if (err < 0) {
1614 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1615 saddr);
1616
1617 goto cleanup;
1618 }
1619
1620 do_cache = res->fi && !itag;
1621 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1622 skb->protocol == htons(ETH_P_IP) &&
1623 (IN_DEV_SHARED_MEDIA(out_dev) ||
1624 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1625 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1626
1627 if (skb->protocol != htons(ETH_P_IP)) {
1628 /* Not IP (i.e. ARP). Do not create route, if it is
1629 * invalid for proxy arp. DNAT routes are always valid.
1630 *
1631 * Proxy arp feature have been extended to allow, ARP
1632 * replies back to the same interface, to support
1633 * Private VLAN switch technologies. See arp.c.
1634 */
1635 if (out_dev == in_dev &&
1636 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1637 err = -EINVAL;
1638 goto cleanup;
1639 }
1640 }
1641
1642 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1643 if (do_cache) {
1644 if (fnhe) {
1645 rth = rcu_dereference(fnhe->fnhe_rth_input);
1646 if (rth && rth->dst.expires &&
1647 time_after(jiffies, rth->dst.expires)) {
1648 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1649 fnhe = NULL;
1650 } else {
1651 goto rt_cache;
1652 }
1653 }
1654
1655 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1656
1657 rt_cache:
1658 if (rt_cache_valid(rth)) {
1659 skb_dst_set_noref(skb, &rth->dst);
1660 goto out;
1661 }
1662 }
1663
1664 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1665 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1666 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1667 if (!rth) {
1668 err = -ENOBUFS;
1669 goto cleanup;
1670 }
1671
1672 rth->rt_is_input = 1;
1673 if (res->table)
1674 rth->rt_table_id = res->table->tb_id;
1675 RT_CACHE_STAT_INC(in_slow_tot);
1676
1677 rth->dst.input = ip_forward;
1678
1679 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1680 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1681 rth->dst.lwtstate->orig_output = rth->dst.output;
1682 rth->dst.output = lwtunnel_output;
1683 }
1684 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1685 rth->dst.lwtstate->orig_input = rth->dst.input;
1686 rth->dst.input = lwtunnel_input;
1687 }
1688 skb_dst_set(skb, &rth->dst);
1689 out:
1690 err = 0;
1691 cleanup:
1692 return err;
1693 }
1694
1695 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1696
1697 /* To make ICMP packets follow the right flow, the multipath hash is
1698 * calculated from the inner IP addresses in reverse order.
1699 */
1700 static int ip_multipath_icmp_hash(struct sk_buff *skb)
1701 {
1702 const struct iphdr *outer_iph = ip_hdr(skb);
1703 struct icmphdr _icmph;
1704 const struct icmphdr *icmph;
1705 struct iphdr _inner_iph;
1706 const struct iphdr *inner_iph;
1707
1708 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1709 goto standard_hash;
1710
1711 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1712 &_icmph);
1713 if (!icmph)
1714 goto standard_hash;
1715
1716 if (icmph->type != ICMP_DEST_UNREACH &&
1717 icmph->type != ICMP_REDIRECT &&
1718 icmph->type != ICMP_TIME_EXCEEDED &&
1719 icmph->type != ICMP_PARAMETERPROB) {
1720 goto standard_hash;
1721 }
1722
1723 inner_iph = skb_header_pointer(skb,
1724 outer_iph->ihl * 4 + sizeof(_icmph),
1725 sizeof(_inner_iph), &_inner_iph);
1726 if (!inner_iph)
1727 goto standard_hash;
1728
1729 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1730
1731 standard_hash:
1732 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1733 }
1734
1735 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1736
1737 static int ip_mkroute_input(struct sk_buff *skb,
1738 struct fib_result *res,
1739 const struct flowi4 *fl4,
1740 struct in_device *in_dev,
1741 __be32 daddr, __be32 saddr, u32 tos)
1742 {
1743 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1744 if (res->fi && res->fi->fib_nhs > 1) {
1745 int h;
1746
1747 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1748 h = ip_multipath_icmp_hash(skb);
1749 else
1750 h = fib_multipath_hash(saddr, daddr);
1751 fib_select_multipath(res, h);
1752 }
1753 #endif
1754
1755 /* create a routing cache entry */
1756 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1757 }
1758
1759 /*
1760 * NOTE. We drop all the packets that has local source
1761 * addresses, because every properly looped back packet
1762 * must have correct destination already attached by output routine.
1763 *
1764 * Such approach solves two big problems:
1765 * 1. Not simplex devices are handled properly.
1766 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1767 * called with rcu_read_lock()
1768 */
1769
1770 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1771 u8 tos, struct net_device *dev)
1772 {
1773 struct fib_result res;
1774 struct in_device *in_dev = __in_dev_get_rcu(dev);
1775 struct ip_tunnel_info *tun_info;
1776 struct flowi4 fl4;
1777 unsigned int flags = 0;
1778 u32 itag = 0;
1779 struct rtable *rth;
1780 int err = -EINVAL;
1781 struct net *net = dev_net(dev);
1782 bool do_cache;
1783
1784 /* IP on this device is disabled. */
1785
1786 if (!in_dev)
1787 goto out;
1788
1789 /* Check for the most weird martians, which can be not detected
1790 by fib_lookup.
1791 */
1792
1793 tun_info = skb_tunnel_info(skb);
1794 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1795 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1796 else
1797 fl4.flowi4_tun_key.tun_id = 0;
1798 skb_dst_drop(skb);
1799
1800 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1801 goto martian_source;
1802
1803 res.fi = NULL;
1804 res.table = NULL;
1805 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1806 goto brd_input;
1807
1808 /* Accept zero addresses only to limited broadcast;
1809 * I even do not know to fix it or not. Waiting for complains :-)
1810 */
1811 if (ipv4_is_zeronet(saddr))
1812 goto martian_source;
1813
1814 if (ipv4_is_zeronet(daddr))
1815 goto martian_destination;
1816
1817 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1818 * and call it once if daddr or/and saddr are loopback addresses
1819 */
1820 if (ipv4_is_loopback(daddr)) {
1821 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1822 goto martian_destination;
1823 } else if (ipv4_is_loopback(saddr)) {
1824 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1825 goto martian_source;
1826 }
1827
1828 /*
1829 * Now we are ready to route packet.
1830 */
1831 fl4.flowi4_oif = 0;
1832 fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev);
1833 fl4.flowi4_mark = skb->mark;
1834 fl4.flowi4_tos = tos;
1835 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1836 fl4.flowi4_flags = 0;
1837 fl4.daddr = daddr;
1838 fl4.saddr = saddr;
1839 err = fib_lookup(net, &fl4, &res, 0);
1840 if (err != 0) {
1841 if (!IN_DEV_FORWARD(in_dev))
1842 err = -EHOSTUNREACH;
1843 goto no_route;
1844 }
1845
1846 if (res.type == RTN_BROADCAST)
1847 goto brd_input;
1848
1849 if (res.type == RTN_LOCAL) {
1850 err = fib_validate_source(skb, saddr, daddr, tos,
1851 0, dev, in_dev, &itag);
1852 if (err < 0)
1853 goto martian_source;
1854 goto local_input;
1855 }
1856
1857 if (!IN_DEV_FORWARD(in_dev)) {
1858 err = -EHOSTUNREACH;
1859 goto no_route;
1860 }
1861 if (res.type != RTN_UNICAST)
1862 goto martian_destination;
1863
1864 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1865 out: return err;
1866
1867 brd_input:
1868 if (skb->protocol != htons(ETH_P_IP))
1869 goto e_inval;
1870
1871 if (!ipv4_is_zeronet(saddr)) {
1872 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1873 in_dev, &itag);
1874 if (err < 0)
1875 goto martian_source;
1876 }
1877 flags |= RTCF_BROADCAST;
1878 res.type = RTN_BROADCAST;
1879 RT_CACHE_STAT_INC(in_brd);
1880
1881 local_input:
1882 do_cache = false;
1883 if (res.fi) {
1884 if (!itag) {
1885 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1886 if (rt_cache_valid(rth)) {
1887 skb_dst_set_noref(skb, &rth->dst);
1888 err = 0;
1889 goto out;
1890 }
1891 do_cache = true;
1892 }
1893 }
1894
1895 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type,
1896 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1897 if (!rth)
1898 goto e_nobufs;
1899
1900 rth->dst.output= ip_rt_bug;
1901 #ifdef CONFIG_IP_ROUTE_CLASSID
1902 rth->dst.tclassid = itag;
1903 #endif
1904 rth->rt_is_input = 1;
1905 if (res.table)
1906 rth->rt_table_id = res.table->tb_id;
1907
1908 RT_CACHE_STAT_INC(in_slow_tot);
1909 if (res.type == RTN_UNREACHABLE) {
1910 rth->dst.input= ip_error;
1911 rth->dst.error= -err;
1912 rth->rt_flags &= ~RTCF_LOCAL;
1913 }
1914 if (do_cache) {
1915 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
1916 rth->dst.flags |= DST_NOCACHE;
1917 rt_add_uncached_list(rth);
1918 }
1919 }
1920 skb_dst_set(skb, &rth->dst);
1921 err = 0;
1922 goto out;
1923
1924 no_route:
1925 RT_CACHE_STAT_INC(in_no_route);
1926 res.type = RTN_UNREACHABLE;
1927 res.fi = NULL;
1928 res.table = NULL;
1929 goto local_input;
1930
1931 /*
1932 * Do not cache martian addresses: they should be logged (RFC1812)
1933 */
1934 martian_destination:
1935 RT_CACHE_STAT_INC(in_martian_dst);
1936 #ifdef CONFIG_IP_ROUTE_VERBOSE
1937 if (IN_DEV_LOG_MARTIANS(in_dev))
1938 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1939 &daddr, &saddr, dev->name);
1940 #endif
1941
1942 e_inval:
1943 err = -EINVAL;
1944 goto out;
1945
1946 e_nobufs:
1947 err = -ENOBUFS;
1948 goto out;
1949
1950 martian_source:
1951 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1952 goto out;
1953 }
1954
1955 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1956 u8 tos, struct net_device *dev)
1957 {
1958 int res;
1959
1960 rcu_read_lock();
1961
1962 /* Multicast recognition logic is moved from route cache to here.
1963 The problem was that too many Ethernet cards have broken/missing
1964 hardware multicast filters :-( As result the host on multicasting
1965 network acquires a lot of useless route cache entries, sort of
1966 SDR messages from all the world. Now we try to get rid of them.
1967 Really, provided software IP multicast filter is organized
1968 reasonably (at least, hashed), it does not result in a slowdown
1969 comparing with route cache reject entries.
1970 Note, that multicast routers are not affected, because
1971 route cache entry is created eventually.
1972 */
1973 if (ipv4_is_multicast(daddr)) {
1974 struct in_device *in_dev = __in_dev_get_rcu(dev);
1975
1976 if (in_dev) {
1977 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1978 ip_hdr(skb)->protocol);
1979 if (our
1980 #ifdef CONFIG_IP_MROUTE
1981 ||
1982 (!ipv4_is_local_multicast(daddr) &&
1983 IN_DEV_MFORWARD(in_dev))
1984 #endif
1985 ) {
1986 int res = ip_route_input_mc(skb, daddr, saddr,
1987 tos, dev, our);
1988 rcu_read_unlock();
1989 return res;
1990 }
1991 }
1992 rcu_read_unlock();
1993 return -EINVAL;
1994 }
1995 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1996 rcu_read_unlock();
1997 return res;
1998 }
1999 EXPORT_SYMBOL(ip_route_input_noref);
2000
2001 /* called with rcu_read_lock() */
2002 static struct rtable *__mkroute_output(const struct fib_result *res,
2003 const struct flowi4 *fl4, int orig_oif,
2004 struct net_device *dev_out,
2005 unsigned int flags)
2006 {
2007 struct fib_info *fi = res->fi;
2008 struct fib_nh_exception *fnhe;
2009 struct in_device *in_dev;
2010 u16 type = res->type;
2011 struct rtable *rth;
2012 bool do_cache;
2013
2014 in_dev = __in_dev_get_rcu(dev_out);
2015 if (!in_dev)
2016 return ERR_PTR(-EINVAL);
2017
2018 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2019 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2020 return ERR_PTR(-EINVAL);
2021
2022 if (ipv4_is_lbcast(fl4->daddr))
2023 type = RTN_BROADCAST;
2024 else if (ipv4_is_multicast(fl4->daddr))
2025 type = RTN_MULTICAST;
2026 else if (ipv4_is_zeronet(fl4->daddr))
2027 return ERR_PTR(-EINVAL);
2028
2029 if (dev_out->flags & IFF_LOOPBACK)
2030 flags |= RTCF_LOCAL;
2031
2032 do_cache = true;
2033 if (type == RTN_BROADCAST) {
2034 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2035 fi = NULL;
2036 } else if (type == RTN_MULTICAST) {
2037 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2038 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2039 fl4->flowi4_proto))
2040 flags &= ~RTCF_LOCAL;
2041 else
2042 do_cache = false;
2043 /* If multicast route do not exist use
2044 * default one, but do not gateway in this case.
2045 * Yes, it is hack.
2046 */
2047 if (fi && res->prefixlen < 4)
2048 fi = NULL;
2049 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2050 (orig_oif != dev_out->ifindex)) {
2051 /* For local routes that require a particular output interface
2052 * we do not want to cache the result. Caching the result
2053 * causes incorrect behaviour when there are multiple source
2054 * addresses on the interface, the end result being that if the
2055 * intended recipient is waiting on that interface for the
2056 * packet he won't receive it because it will be delivered on
2057 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2058 * be set to the loopback interface as well.
2059 */
2060 fi = NULL;
2061 }
2062
2063 fnhe = NULL;
2064 do_cache &= fi != NULL;
2065 if (do_cache) {
2066 struct rtable __rcu **prth;
2067 struct fib_nh *nh = &FIB_RES_NH(*res);
2068
2069 fnhe = find_exception(nh, fl4->daddr);
2070 if (fnhe) {
2071 prth = &fnhe->fnhe_rth_output;
2072 rth = rcu_dereference(*prth);
2073 if (rth && rth->dst.expires &&
2074 time_after(jiffies, rth->dst.expires)) {
2075 ip_del_fnhe(nh, fl4->daddr);
2076 fnhe = NULL;
2077 } else {
2078 goto rt_cache;
2079 }
2080 }
2081
2082 if (unlikely(fl4->flowi4_flags &
2083 FLOWI_FLAG_KNOWN_NH &&
2084 !(nh->nh_gw &&
2085 nh->nh_scope == RT_SCOPE_LINK))) {
2086 do_cache = false;
2087 goto add;
2088 }
2089 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2090 rth = rcu_dereference(*prth);
2091
2092 rt_cache:
2093 if (rt_cache_valid(rth)) {
2094 dst_hold(&rth->dst);
2095 return rth;
2096 }
2097 }
2098
2099 add:
2100 rth = rt_dst_alloc(dev_out, flags, type,
2101 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2102 IN_DEV_CONF_GET(in_dev, NOXFRM),
2103 do_cache);
2104 if (!rth)
2105 return ERR_PTR(-ENOBUFS);
2106
2107 rth->rt_iif = orig_oif ? : 0;
2108 if (res->table)
2109 rth->rt_table_id = res->table->tb_id;
2110
2111 RT_CACHE_STAT_INC(out_slow_tot);
2112
2113 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2114 if (flags & RTCF_LOCAL &&
2115 !(dev_out->flags & IFF_LOOPBACK)) {
2116 rth->dst.output = ip_mc_output;
2117 RT_CACHE_STAT_INC(out_slow_mc);
2118 }
2119 #ifdef CONFIG_IP_MROUTE
2120 if (type == RTN_MULTICAST) {
2121 if (IN_DEV_MFORWARD(in_dev) &&
2122 !ipv4_is_local_multicast(fl4->daddr)) {
2123 rth->dst.input = ip_mr_input;
2124 rth->dst.output = ip_mc_output;
2125 }
2126 }
2127 #endif
2128 }
2129
2130 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2131 if (lwtunnel_output_redirect(rth->dst.lwtstate))
2132 rth->dst.output = lwtunnel_output;
2133
2134 return rth;
2135 }
2136
2137 /*
2138 * Major route resolver routine.
2139 */
2140
2141 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2142 int mp_hash)
2143 {
2144 struct net_device *dev_out = NULL;
2145 __u8 tos = RT_FL_TOS(fl4);
2146 unsigned int flags = 0;
2147 struct fib_result res;
2148 struct rtable *rth;
2149 int master_idx;
2150 int orig_oif;
2151 int err = -ENETUNREACH;
2152
2153 res.tclassid = 0;
2154 res.fi = NULL;
2155 res.table = NULL;
2156
2157 orig_oif = fl4->flowi4_oif;
2158
2159 master_idx = l3mdev_master_ifindex_by_index(net, fl4->flowi4_oif);
2160 if (master_idx)
2161 fl4->flowi4_oif = master_idx;
2162 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2163 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2164 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2165 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2166
2167 rcu_read_lock();
2168 if (fl4->saddr) {
2169 rth = ERR_PTR(-EINVAL);
2170 if (ipv4_is_multicast(fl4->saddr) ||
2171 ipv4_is_lbcast(fl4->saddr) ||
2172 ipv4_is_zeronet(fl4->saddr))
2173 goto out;
2174
2175 /* I removed check for oif == dev_out->oif here.
2176 It was wrong for two reasons:
2177 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2178 is assigned to multiple interfaces.
2179 2. Moreover, we are allowed to send packets with saddr
2180 of another iface. --ANK
2181 */
2182
2183 if (fl4->flowi4_oif == 0 &&
2184 (ipv4_is_multicast(fl4->daddr) ||
2185 ipv4_is_lbcast(fl4->daddr))) {
2186 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2187 dev_out = __ip_dev_find(net, fl4->saddr, false);
2188 if (!dev_out)
2189 goto out;
2190
2191 /* Special hack: user can direct multicasts
2192 and limited broadcast via necessary interface
2193 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2194 This hack is not just for fun, it allows
2195 vic,vat and friends to work.
2196 They bind socket to loopback, set ttl to zero
2197 and expect that it will work.
2198 From the viewpoint of routing cache they are broken,
2199 because we are not allowed to build multicast path
2200 with loopback source addr (look, routing cache
2201 cannot know, that ttl is zero, so that packet
2202 will not leave this host and route is valid).
2203 Luckily, this hack is good workaround.
2204 */
2205
2206 fl4->flowi4_oif = dev_out->ifindex;
2207 goto make_route;
2208 }
2209
2210 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2211 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2212 if (!__ip_dev_find(net, fl4->saddr, false))
2213 goto out;
2214 }
2215 }
2216
2217
2218 if (fl4->flowi4_oif) {
2219 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2220 rth = ERR_PTR(-ENODEV);
2221 if (!dev_out)
2222 goto out;
2223
2224 /* RACE: Check return value of inet_select_addr instead. */
2225 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2226 rth = ERR_PTR(-ENETUNREACH);
2227 goto out;
2228 }
2229 if (ipv4_is_local_multicast(fl4->daddr) ||
2230 ipv4_is_lbcast(fl4->daddr) ||
2231 fl4->flowi4_proto == IPPROTO_IGMP) {
2232 if (!fl4->saddr)
2233 fl4->saddr = inet_select_addr(dev_out, 0,
2234 RT_SCOPE_LINK);
2235 goto make_route;
2236 }
2237 if (!fl4->saddr) {
2238 if (ipv4_is_multicast(fl4->daddr))
2239 fl4->saddr = inet_select_addr(dev_out, 0,
2240 fl4->flowi4_scope);
2241 else if (!fl4->daddr)
2242 fl4->saddr = inet_select_addr(dev_out, 0,
2243 RT_SCOPE_HOST);
2244 }
2245
2246 rth = l3mdev_get_rtable(dev_out, fl4);
2247 if (rth)
2248 goto out;
2249 }
2250
2251 if (!fl4->daddr) {
2252 fl4->daddr = fl4->saddr;
2253 if (!fl4->daddr)
2254 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2255 dev_out = net->loopback_dev;
2256 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2257 res.type = RTN_LOCAL;
2258 flags |= RTCF_LOCAL;
2259 goto make_route;
2260 }
2261
2262 err = fib_lookup(net, fl4, &res, 0);
2263 if (err) {
2264 res.fi = NULL;
2265 res.table = NULL;
2266 if (fl4->flowi4_oif &&
2267 !netif_index_is_l3_master(net, fl4->flowi4_oif)) {
2268 /* Apparently, routing tables are wrong. Assume,
2269 that the destination is on link.
2270
2271 WHY? DW.
2272 Because we are allowed to send to iface
2273 even if it has NO routes and NO assigned
2274 addresses. When oif is specified, routing
2275 tables are looked up with only one purpose:
2276 to catch if destination is gatewayed, rather than
2277 direct. Moreover, if MSG_DONTROUTE is set,
2278 we send packet, ignoring both routing tables
2279 and ifaddr state. --ANK
2280
2281
2282 We could make it even if oif is unknown,
2283 likely IPv6, but we do not.
2284 */
2285
2286 if (fl4->saddr == 0)
2287 fl4->saddr = inet_select_addr(dev_out, 0,
2288 RT_SCOPE_LINK);
2289 res.type = RTN_UNICAST;
2290 goto make_route;
2291 }
2292 rth = ERR_PTR(err);
2293 goto out;
2294 }
2295
2296 if (res.type == RTN_LOCAL) {
2297 if (!fl4->saddr) {
2298 if (res.fi->fib_prefsrc)
2299 fl4->saddr = res.fi->fib_prefsrc;
2300 else
2301 fl4->saddr = fl4->daddr;
2302 }
2303 dev_out = net->loopback_dev;
2304 fl4->flowi4_oif = dev_out->ifindex;
2305 flags |= RTCF_LOCAL;
2306 goto make_route;
2307 }
2308
2309 fib_select_path(net, &res, fl4, mp_hash);
2310
2311 dev_out = FIB_RES_DEV(res);
2312 fl4->flowi4_oif = dev_out->ifindex;
2313
2314
2315 make_route:
2316 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2317
2318 out:
2319 rcu_read_unlock();
2320 return rth;
2321 }
2322 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2323
2324 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2325 {
2326 return NULL;
2327 }
2328
2329 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2330 {
2331 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2332
2333 return mtu ? : dst->dev->mtu;
2334 }
2335
2336 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2337 struct sk_buff *skb, u32 mtu)
2338 {
2339 }
2340
2341 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2342 struct sk_buff *skb)
2343 {
2344 }
2345
2346 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2347 unsigned long old)
2348 {
2349 return NULL;
2350 }
2351
2352 static struct dst_ops ipv4_dst_blackhole_ops = {
2353 .family = AF_INET,
2354 .check = ipv4_blackhole_dst_check,
2355 .mtu = ipv4_blackhole_mtu,
2356 .default_advmss = ipv4_default_advmss,
2357 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2358 .redirect = ipv4_rt_blackhole_redirect,
2359 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2360 .neigh_lookup = ipv4_neigh_lookup,
2361 };
2362
2363 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2364 {
2365 struct rtable *ort = (struct rtable *) dst_orig;
2366 struct rtable *rt;
2367
2368 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2369 if (rt) {
2370 struct dst_entry *new = &rt->dst;
2371
2372 new->__use = 1;
2373 new->input = dst_discard;
2374 new->output = dst_discard_out;
2375
2376 new->dev = ort->dst.dev;
2377 if (new->dev)
2378 dev_hold(new->dev);
2379
2380 rt->rt_is_input = ort->rt_is_input;
2381 rt->rt_iif = ort->rt_iif;
2382 rt->rt_pmtu = ort->rt_pmtu;
2383
2384 rt->rt_genid = rt_genid_ipv4(net);
2385 rt->rt_flags = ort->rt_flags;
2386 rt->rt_type = ort->rt_type;
2387 rt->rt_gateway = ort->rt_gateway;
2388 rt->rt_uses_gateway = ort->rt_uses_gateway;
2389
2390 INIT_LIST_HEAD(&rt->rt_uncached);
2391 dst_free(new);
2392 }
2393
2394 dst_release(dst_orig);
2395
2396 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2397 }
2398
2399 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2400 const struct sock *sk)
2401 {
2402 struct rtable *rt = __ip_route_output_key(net, flp4);
2403
2404 if (IS_ERR(rt))
2405 return rt;
2406
2407 if (flp4->flowi4_proto)
2408 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2409 flowi4_to_flowi(flp4),
2410 sk, 0);
2411
2412 return rt;
2413 }
2414 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2415
2416 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2417 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2418 u32 seq, int event, int nowait, unsigned int flags)
2419 {
2420 struct rtable *rt = skb_rtable(skb);
2421 struct rtmsg *r;
2422 struct nlmsghdr *nlh;
2423 unsigned long expires = 0;
2424 u32 error;
2425 u32 metrics[RTAX_MAX];
2426
2427 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2428 if (!nlh)
2429 return -EMSGSIZE;
2430
2431 r = nlmsg_data(nlh);
2432 r->rtm_family = AF_INET;
2433 r->rtm_dst_len = 32;
2434 r->rtm_src_len = 0;
2435 r->rtm_tos = fl4->flowi4_tos;
2436 r->rtm_table = table_id;
2437 if (nla_put_u32(skb, RTA_TABLE, table_id))
2438 goto nla_put_failure;
2439 r->rtm_type = rt->rt_type;
2440 r->rtm_scope = RT_SCOPE_UNIVERSE;
2441 r->rtm_protocol = RTPROT_UNSPEC;
2442 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2443 if (rt->rt_flags & RTCF_NOTIFY)
2444 r->rtm_flags |= RTM_F_NOTIFY;
2445 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2446 r->rtm_flags |= RTCF_DOREDIRECT;
2447
2448 if (nla_put_in_addr(skb, RTA_DST, dst))
2449 goto nla_put_failure;
2450 if (src) {
2451 r->rtm_src_len = 32;
2452 if (nla_put_in_addr(skb, RTA_SRC, src))
2453 goto nla_put_failure;
2454 }
2455 if (rt->dst.dev &&
2456 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2457 goto nla_put_failure;
2458 #ifdef CONFIG_IP_ROUTE_CLASSID
2459 if (rt->dst.tclassid &&
2460 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2461 goto nla_put_failure;
2462 #endif
2463 if (!rt_is_input_route(rt) &&
2464 fl4->saddr != src) {
2465 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2466 goto nla_put_failure;
2467 }
2468 if (rt->rt_uses_gateway &&
2469 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2470 goto nla_put_failure;
2471
2472 expires = rt->dst.expires;
2473 if (expires) {
2474 unsigned long now = jiffies;
2475
2476 if (time_before(now, expires))
2477 expires -= now;
2478 else
2479 expires = 0;
2480 }
2481
2482 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2483 if (rt->rt_pmtu && expires)
2484 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2485 if (rtnetlink_put_metrics(skb, metrics) < 0)
2486 goto nla_put_failure;
2487
2488 if (fl4->flowi4_mark &&
2489 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2490 goto nla_put_failure;
2491
2492 error = rt->dst.error;
2493
2494 if (rt_is_input_route(rt)) {
2495 #ifdef CONFIG_IP_MROUTE
2496 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2497 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2498 int err = ipmr_get_route(net, skb,
2499 fl4->saddr, fl4->daddr,
2500 r, nowait);
2501 if (err <= 0) {
2502 if (!nowait) {
2503 if (err == 0)
2504 return 0;
2505 goto nla_put_failure;
2506 } else {
2507 if (err == -EMSGSIZE)
2508 goto nla_put_failure;
2509 error = err;
2510 }
2511 }
2512 } else
2513 #endif
2514 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2515 goto nla_put_failure;
2516 }
2517
2518 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2519 goto nla_put_failure;
2520
2521 nlmsg_end(skb, nlh);
2522 return 0;
2523
2524 nla_put_failure:
2525 nlmsg_cancel(skb, nlh);
2526 return -EMSGSIZE;
2527 }
2528
2529 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2530 {
2531 struct net *net = sock_net(in_skb->sk);
2532 struct rtmsg *rtm;
2533 struct nlattr *tb[RTA_MAX+1];
2534 struct rtable *rt = NULL;
2535 struct flowi4 fl4;
2536 __be32 dst = 0;
2537 __be32 src = 0;
2538 u32 iif;
2539 int err;
2540 int mark;
2541 struct sk_buff *skb;
2542 u32 table_id = RT_TABLE_MAIN;
2543
2544 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2545 if (err < 0)
2546 goto errout;
2547
2548 rtm = nlmsg_data(nlh);
2549
2550 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2551 if (!skb) {
2552 err = -ENOBUFS;
2553 goto errout;
2554 }
2555
2556 /* Reserve room for dummy headers, this skb can pass
2557 through good chunk of routing engine.
2558 */
2559 skb_reset_mac_header(skb);
2560 skb_reset_network_header(skb);
2561
2562 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2563 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2564 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2565
2566 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2567 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2568 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2569 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2570
2571 memset(&fl4, 0, sizeof(fl4));
2572 fl4.daddr = dst;
2573 fl4.saddr = src;
2574 fl4.flowi4_tos = rtm->rtm_tos;
2575 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2576 fl4.flowi4_mark = mark;
2577
2578 if (netif_index_is_l3_master(net, fl4.flowi4_oif))
2579 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF;
2580
2581 if (iif) {
2582 struct net_device *dev;
2583
2584 dev = __dev_get_by_index(net, iif);
2585 if (!dev) {
2586 err = -ENODEV;
2587 goto errout_free;
2588 }
2589
2590 skb->protocol = htons(ETH_P_IP);
2591 skb->dev = dev;
2592 skb->mark = mark;
2593 local_bh_disable();
2594 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2595 local_bh_enable();
2596
2597 rt = skb_rtable(skb);
2598 if (err == 0 && rt->dst.error)
2599 err = -rt->dst.error;
2600 } else {
2601 rt = ip_route_output_key(net, &fl4);
2602
2603 err = 0;
2604 if (IS_ERR(rt))
2605 err = PTR_ERR(rt);
2606 }
2607
2608 if (err)
2609 goto errout_free;
2610
2611 skb_dst_set(skb, &rt->dst);
2612 if (rtm->rtm_flags & RTM_F_NOTIFY)
2613 rt->rt_flags |= RTCF_NOTIFY;
2614
2615 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2616 table_id = rt->rt_table_id;
2617
2618 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2619 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2620 RTM_NEWROUTE, 0, 0);
2621 if (err < 0)
2622 goto errout_free;
2623
2624 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2625 errout:
2626 return err;
2627
2628 errout_free:
2629 kfree_skb(skb);
2630 goto errout;
2631 }
2632
2633 void ip_rt_multicast_event(struct in_device *in_dev)
2634 {
2635 rt_cache_flush(dev_net(in_dev->dev));
2636 }
2637
2638 #ifdef CONFIG_SYSCTL
2639 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2640 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2641 static int ip_rt_gc_elasticity __read_mostly = 8;
2642
2643 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2644 void __user *buffer,
2645 size_t *lenp, loff_t *ppos)
2646 {
2647 struct net *net = (struct net *)__ctl->extra1;
2648
2649 if (write) {
2650 rt_cache_flush(net);
2651 fnhe_genid_bump(net);
2652 return 0;
2653 }
2654
2655 return -EINVAL;
2656 }
2657
2658 static struct ctl_table ipv4_route_table[] = {
2659 {
2660 .procname = "gc_thresh",
2661 .data = &ipv4_dst_ops.gc_thresh,
2662 .maxlen = sizeof(int),
2663 .mode = 0644,
2664 .proc_handler = proc_dointvec,
2665 },
2666 {
2667 .procname = "max_size",
2668 .data = &ip_rt_max_size,
2669 .maxlen = sizeof(int),
2670 .mode = 0644,
2671 .proc_handler = proc_dointvec,
2672 },
2673 {
2674 /* Deprecated. Use gc_min_interval_ms */
2675
2676 .procname = "gc_min_interval",
2677 .data = &ip_rt_gc_min_interval,
2678 .maxlen = sizeof(int),
2679 .mode = 0644,
2680 .proc_handler = proc_dointvec_jiffies,
2681 },
2682 {
2683 .procname = "gc_min_interval_ms",
2684 .data = &ip_rt_gc_min_interval,
2685 .maxlen = sizeof(int),
2686 .mode = 0644,
2687 .proc_handler = proc_dointvec_ms_jiffies,
2688 },
2689 {
2690 .procname = "gc_timeout",
2691 .data = &ip_rt_gc_timeout,
2692 .maxlen = sizeof(int),
2693 .mode = 0644,
2694 .proc_handler = proc_dointvec_jiffies,
2695 },
2696 {
2697 .procname = "gc_interval",
2698 .data = &ip_rt_gc_interval,
2699 .maxlen = sizeof(int),
2700 .mode = 0644,
2701 .proc_handler = proc_dointvec_jiffies,
2702 },
2703 {
2704 .procname = "redirect_load",
2705 .data = &ip_rt_redirect_load,
2706 .maxlen = sizeof(int),
2707 .mode = 0644,
2708 .proc_handler = proc_dointvec,
2709 },
2710 {
2711 .procname = "redirect_number",
2712 .data = &ip_rt_redirect_number,
2713 .maxlen = sizeof(int),
2714 .mode = 0644,
2715 .proc_handler = proc_dointvec,
2716 },
2717 {
2718 .procname = "redirect_silence",
2719 .data = &ip_rt_redirect_silence,
2720 .maxlen = sizeof(int),
2721 .mode = 0644,
2722 .proc_handler = proc_dointvec,
2723 },
2724 {
2725 .procname = "error_cost",
2726 .data = &ip_rt_error_cost,
2727 .maxlen = sizeof(int),
2728 .mode = 0644,
2729 .proc_handler = proc_dointvec,
2730 },
2731 {
2732 .procname = "error_burst",
2733 .data = &ip_rt_error_burst,
2734 .maxlen = sizeof(int),
2735 .mode = 0644,
2736 .proc_handler = proc_dointvec,
2737 },
2738 {
2739 .procname = "gc_elasticity",
2740 .data = &ip_rt_gc_elasticity,
2741 .maxlen = sizeof(int),
2742 .mode = 0644,
2743 .proc_handler = proc_dointvec,
2744 },
2745 {
2746 .procname = "mtu_expires",
2747 .data = &ip_rt_mtu_expires,
2748 .maxlen = sizeof(int),
2749 .mode = 0644,
2750 .proc_handler = proc_dointvec_jiffies,
2751 },
2752 {
2753 .procname = "min_pmtu",
2754 .data = &ip_rt_min_pmtu,
2755 .maxlen = sizeof(int),
2756 .mode = 0644,
2757 .proc_handler = proc_dointvec,
2758 },
2759 {
2760 .procname = "min_adv_mss",
2761 .data = &ip_rt_min_advmss,
2762 .maxlen = sizeof(int),
2763 .mode = 0644,
2764 .proc_handler = proc_dointvec,
2765 },
2766 { }
2767 };
2768
2769 static struct ctl_table ipv4_route_flush_table[] = {
2770 {
2771 .procname = "flush",
2772 .maxlen = sizeof(int),
2773 .mode = 0200,
2774 .proc_handler = ipv4_sysctl_rtcache_flush,
2775 },
2776 { },
2777 };
2778
2779 static __net_init int sysctl_route_net_init(struct net *net)
2780 {
2781 struct ctl_table *tbl;
2782
2783 tbl = ipv4_route_flush_table;
2784 if (!net_eq(net, &init_net)) {
2785 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2786 if (!tbl)
2787 goto err_dup;
2788
2789 /* Don't export sysctls to unprivileged users */
2790 if (net->user_ns != &init_user_ns)
2791 tbl[0].procname = NULL;
2792 }
2793 tbl[0].extra1 = net;
2794
2795 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2796 if (!net->ipv4.route_hdr)
2797 goto err_reg;
2798 return 0;
2799
2800 err_reg:
2801 if (tbl != ipv4_route_flush_table)
2802 kfree(tbl);
2803 err_dup:
2804 return -ENOMEM;
2805 }
2806
2807 static __net_exit void sysctl_route_net_exit(struct net *net)
2808 {
2809 struct ctl_table *tbl;
2810
2811 tbl = net->ipv4.route_hdr->ctl_table_arg;
2812 unregister_net_sysctl_table(net->ipv4.route_hdr);
2813 BUG_ON(tbl == ipv4_route_flush_table);
2814 kfree(tbl);
2815 }
2816
2817 static __net_initdata struct pernet_operations sysctl_route_ops = {
2818 .init = sysctl_route_net_init,
2819 .exit = sysctl_route_net_exit,
2820 };
2821 #endif
2822
2823 static __net_init int rt_genid_init(struct net *net)
2824 {
2825 atomic_set(&net->ipv4.rt_genid, 0);
2826 atomic_set(&net->fnhe_genid, 0);
2827 get_random_bytes(&net->ipv4.dev_addr_genid,
2828 sizeof(net->ipv4.dev_addr_genid));
2829 return 0;
2830 }
2831
2832 static __net_initdata struct pernet_operations rt_genid_ops = {
2833 .init = rt_genid_init,
2834 };
2835
2836 static int __net_init ipv4_inetpeer_init(struct net *net)
2837 {
2838 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2839
2840 if (!bp)
2841 return -ENOMEM;
2842 inet_peer_base_init(bp);
2843 net->ipv4.peers = bp;
2844 return 0;
2845 }
2846
2847 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2848 {
2849 struct inet_peer_base *bp = net->ipv4.peers;
2850
2851 net->ipv4.peers = NULL;
2852 inetpeer_invalidate_tree(bp);
2853 kfree(bp);
2854 }
2855
2856 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2857 .init = ipv4_inetpeer_init,
2858 .exit = ipv4_inetpeer_exit,
2859 };
2860
2861 #ifdef CONFIG_IP_ROUTE_CLASSID
2862 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2863 #endif /* CONFIG_IP_ROUTE_CLASSID */
2864
2865 int __init ip_rt_init(void)
2866 {
2867 int rc = 0;
2868 int cpu;
2869
2870 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2871 if (!ip_idents)
2872 panic("IP: failed to allocate ip_idents\n");
2873
2874 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2875
2876 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2877 if (!ip_tstamps)
2878 panic("IP: failed to allocate ip_tstamps\n");
2879
2880 for_each_possible_cpu(cpu) {
2881 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2882
2883 INIT_LIST_HEAD(&ul->head);
2884 spin_lock_init(&ul->lock);
2885 }
2886 #ifdef CONFIG_IP_ROUTE_CLASSID
2887 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2888 if (!ip_rt_acct)
2889 panic("IP: failed to allocate ip_rt_acct\n");
2890 #endif
2891
2892 ipv4_dst_ops.kmem_cachep =
2893 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2894 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2895
2896 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2897
2898 if (dst_entries_init(&ipv4_dst_ops) < 0)
2899 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2900
2901 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2902 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2903
2904 ipv4_dst_ops.gc_thresh = ~0;
2905 ip_rt_max_size = INT_MAX;
2906
2907 devinet_init();
2908 ip_fib_init();
2909
2910 if (ip_rt_proc_init())
2911 pr_err("Unable to create route proc files\n");
2912 #ifdef CONFIG_XFRM
2913 xfrm_init();
2914 xfrm4_init();
2915 #endif
2916 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2917
2918 #ifdef CONFIG_SYSCTL
2919 register_pernet_subsys(&sysctl_route_ops);
2920 #endif
2921 register_pernet_subsys(&rt_genid_ops);
2922 register_pernet_subsys(&ipv4_inetpeer_ops);
2923 return rc;
2924 }
2925
2926 #ifdef CONFIG_SYSCTL
2927 /*
2928 * We really need to sanitize the damn ipv4 init order, then all
2929 * this nonsense will go away.
2930 */
2931 void __init ip_static_sysctl_init(void)
2932 {
2933 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2934 }
2935 #endif
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