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