]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - net/ipv4/route.c
projects / mirror_ubuntu-artful-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Merge tag 'iio-for-4.13b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23...
[mirror_ubuntu-artful-kernel.git] / net / ipv4 / route.c
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * ROUTE - implementation of the IP router.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox, <gw4pts@gw4pts.ampr.org>
11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
13 *
14 * Fixes:
15 * Alan Cox : Verify area fixes.
16 * Alan Cox : cli() protects routing changes
17 * Rui Oliveira : ICMP routing table updates
18 * (rco@di.uminho.pt) Routing table insertion and update
19 * Linus Torvalds : Rewrote bits to be sensible
20 * Alan Cox : Added BSD route gw semantics
21 * Alan Cox : Super /proc >4K
22 * Alan Cox : MTU in route table
23 * Alan Cox : MSS actually. Also added the window
24 * clamper.
25 * Sam Lantinga : Fixed route matching in rt_del()
26 * Alan Cox : Routing cache support.
27 * Alan Cox : Removed compatibility cruft.
28 * Alan Cox : RTF_REJECT support.
29 * Alan Cox : TCP irtt support.
30 * Jonathan Naylor : Added Metric support.
31 * Miquel van Smoorenburg : BSD API fixes.
32 * Miquel van Smoorenburg : Metrics.
33 * Alan Cox : Use __u32 properly
34 * Alan Cox : Aligned routing errors more closely with BSD
35 * our system is still very different.
36 * Alan Cox : Faster /proc handling
37 * Alexey Kuznetsov : Massive rework to support tree based routing,
38 * routing caches and better behaviour.
39 *
40 * Olaf Erb : irtt wasn't being copied right.
41 * Bjorn Ekwall : Kerneld route support.
42 * Alan Cox : Multicast fixed (I hope)
43 * Pavel Krauz : Limited broadcast fixed
44 * Mike McLagan : Routing by source
45 * Alexey Kuznetsov : End of old history. Split to fib.c and
46 * route.c and rewritten from scratch.
47 * Andi Kleen : Load-limit warning messages.
48 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
52 * Marc Boucher : routing by fwmark
53 * Robert Olsson : Added rt_cache statistics
54 * Arnaldo C. Melo : Convert proc stuff to seq_file
55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
57 * Ilia Sotnikov : Removed TOS from hash calculations
58 *
59 * This program is free software; you can redistribute it and/or
60 * modify it under the terms of the GNU General Public License
61 * as published by the Free Software Foundation; either version
62 * 2 of the License, or (at your option) any later version.
63 */
64
65 #define pr_fmt(fmt) "IPv4: " fmt
66
67 #include <linux/module.h>
68 #include <linux/uaccess.h>
69 #include <linux/bitops.h>
70 #include <linux/types.h>
71 #include <linux/kernel.h>
72 #include <linux/mm.h>
73 #include <linux/string.h>
74 #include <linux/socket.h>
75 #include <linux/sockios.h>
76 #include <linux/errno.h>
77 #include <linux/in.h>
78 #include <linux/inet.h>
79 #include <linux/netdevice.h>
80 #include <linux/proc_fs.h>
81 #include <linux/init.h>
82 #include <linux/skbuff.h>
83 #include <linux/inetdevice.h>
84 #include <linux/igmp.h>
85 #include <linux/pkt_sched.h>
86 #include <linux/mroute.h>
87 #include <linux/netfilter_ipv4.h>
88 #include <linux/random.h>
89 #include <linux/rcupdate.h>
90 #include <linux/times.h>
91 #include <linux/slab.h>
92 #include <linux/jhash.h>
93 #include <net/dst.h>
94 #include <net/dst_metadata.h>
95 #include <net/net_namespace.h>
96 #include <net/protocol.h>
97 #include <net/ip.h>
98 #include <net/route.h>
99 #include <net/inetpeer.h>
100 #include <net/sock.h>
101 #include <net/ip_fib.h>
102 #include <net/arp.h>
103 #include <net/tcp.h>
104 #include <net/icmp.h>
105 #include <net/xfrm.h>
106 #include <net/lwtunnel.h>
107 #include <net/netevent.h>
108 #include <net/rtnetlink.h>
109 #ifdef CONFIG_SYSCTL
110 #include <linux/sysctl.h>
111 #include <linux/kmemleak.h>
112 #endif
113 #include <net/secure_seq.h>
114 #include <net/ip_tunnels.h>
115 #include <net/l3mdev.h>
116
117 #define RT_FL_TOS(oldflp4) \
118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
119
120 #define RT_GC_TIMEOUT (300*HZ)
121
122 static int ip_rt_max_size;
123 static int ip_rt_redirect_number __read_mostly = 9;
124 static int ip_rt_redirect_load __read_mostly = HZ / 50;
125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
126 static int ip_rt_error_cost __read_mostly = HZ;
127 static int ip_rt_error_burst __read_mostly = 5 * HZ;
128 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
129 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
130 static int ip_rt_min_advmss __read_mostly = 256;
131
132 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
133 /*
134 * Interface to generic destination cache.
135 */
136
137 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
138 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
139 static unsigned int ipv4_mtu(const struct dst_entry *dst);
140 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
141 static void ipv4_link_failure(struct sk_buff *skb);
142 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
143 struct sk_buff *skb, u32 mtu);
144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146 static void ipv4_dst_destroy(struct dst_entry *dst);
147
148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
149 {
150 WARN_ON(1);
151 return NULL;
152 }
153
154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
155 struct sk_buff *skb,
156 const void *daddr);
157 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
158
159 static struct dst_ops ipv4_dst_ops = {
160 .family = AF_INET,
161 .check = ipv4_dst_check,
162 .default_advmss = ipv4_default_advmss,
163 .mtu = ipv4_mtu,
164 .cow_metrics = ipv4_cow_metrics,
165 .destroy = ipv4_dst_destroy,
166 .negative_advice = ipv4_negative_advice,
167 .link_failure = ipv4_link_failure,
168 .update_pmtu = ip_rt_update_pmtu,
169 .redirect = ip_do_redirect,
170 .local_out = __ip_local_out,
171 .neigh_lookup = ipv4_neigh_lookup,
172 .confirm_neigh = ipv4_confirm_neigh,
173 };
174
175 #define ECN_OR_COST(class) TC_PRIO_##class
176
177 const __u8 ip_tos2prio[16] = {
178 TC_PRIO_BESTEFFORT,
179 ECN_OR_COST(BESTEFFORT),
180 TC_PRIO_BESTEFFORT,
181 ECN_OR_COST(BESTEFFORT),
182 TC_PRIO_BULK,
183 ECN_OR_COST(BULK),
184 TC_PRIO_BULK,
185 ECN_OR_COST(BULK),
186 TC_PRIO_INTERACTIVE,
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE,
189 ECN_OR_COST(INTERACTIVE),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK),
192 TC_PRIO_INTERACTIVE_BULK,
193 ECN_OR_COST(INTERACTIVE_BULK)
194 };
195 EXPORT_SYMBOL(ip_tos2prio);
196
197 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
198 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
199
200 #ifdef CONFIG_PROC_FS
201 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
202 {
203 if (*pos)
204 return NULL;
205 return SEQ_START_TOKEN;
206 }
207
208 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
209 {
210 ++*pos;
211 return NULL;
212 }
213
214 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
215 {
216 }
217
218 static int rt_cache_seq_show(struct seq_file *seq, void *v)
219 {
220 if (v == SEQ_START_TOKEN)
221 seq_printf(seq, "%-127s\n",
222 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
223 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
224 "HHUptod\tSpecDst");
225 return 0;
226 }
227
228 static const struct seq_operations rt_cache_seq_ops = {
229 .start = rt_cache_seq_start,
230 .next = rt_cache_seq_next,
231 .stop = rt_cache_seq_stop,
232 .show = rt_cache_seq_show,
233 };
234
235 static int rt_cache_seq_open(struct inode *inode, struct file *file)
236 {
237 return seq_open(file, &rt_cache_seq_ops);
238 }
239
240 static const struct file_operations rt_cache_seq_fops = {
241 .owner = THIS_MODULE,
242 .open = rt_cache_seq_open,
243 .read = seq_read,
244 .llseek = seq_lseek,
245 .release = seq_release,
246 };
247
248
249 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
250 {
251 int cpu;
252
253 if (*pos == 0)
254 return SEQ_START_TOKEN;
255
256 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
257 if (!cpu_possible(cpu))
258 continue;
259 *pos = cpu+1;
260 return &per_cpu(rt_cache_stat, cpu);
261 }
262 return NULL;
263 }
264
265 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
266 {
267 int cpu;
268
269 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
270 if (!cpu_possible(cpu))
271 continue;
272 *pos = cpu+1;
273 return &per_cpu(rt_cache_stat, cpu);
274 }
275 return NULL;
276
277 }
278
279 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
280 {
281
282 }
283
284 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
285 {
286 struct rt_cache_stat *st = v;
287
288 if (v == SEQ_START_TOKEN) {
289 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
290 return 0;
291 }
292
293 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
294 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
295 dst_entries_get_slow(&ipv4_dst_ops),
296 0, /* st->in_hit */
297 st->in_slow_tot,
298 st->in_slow_mc,
299 st->in_no_route,
300 st->in_brd,
301 st->in_martian_dst,
302 st->in_martian_src,
303
304 0, /* st->out_hit */
305 st->out_slow_tot,
306 st->out_slow_mc,
307
308 0, /* st->gc_total */
309 0, /* st->gc_ignored */
310 0, /* st->gc_goal_miss */
311 0, /* st->gc_dst_overflow */
312 0, /* st->in_hlist_search */
313 0 /* st->out_hlist_search */
314 );
315 return 0;
316 }
317
318 static const struct seq_operations rt_cpu_seq_ops = {
319 .start = rt_cpu_seq_start,
320 .next = rt_cpu_seq_next,
321 .stop = rt_cpu_seq_stop,
322 .show = rt_cpu_seq_show,
323 };
324
325
326 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
327 {
328 return seq_open(file, &rt_cpu_seq_ops);
329 }
330
331 static const struct file_operations rt_cpu_seq_fops = {
332 .owner = THIS_MODULE,
333 .open = rt_cpu_seq_open,
334 .read = seq_read,
335 .llseek = seq_lseek,
336 .release = seq_release,
337 };
338
339 #ifdef CONFIG_IP_ROUTE_CLASSID
340 static int rt_acct_proc_show(struct seq_file *m, void *v)
341 {
342 struct ip_rt_acct *dst, *src;
343 unsigned int i, j;
344
345 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
346 if (!dst)
347 return -ENOMEM;
348
349 for_each_possible_cpu(i) {
350 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
351 for (j = 0; j < 256; j++) {
352 dst[j].o_bytes += src[j].o_bytes;
353 dst[j].o_packets += src[j].o_packets;
354 dst[j].i_bytes += src[j].i_bytes;
355 dst[j].i_packets += src[j].i_packets;
356 }
357 }
358
359 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
360 kfree(dst);
361 return 0;
362 }
363
364 static int rt_acct_proc_open(struct inode *inode, struct file *file)
365 {
366 return single_open(file, rt_acct_proc_show, NULL);
367 }
368
369 static const struct file_operations rt_acct_proc_fops = {
370 .owner = THIS_MODULE,
371 .open = rt_acct_proc_open,
372 .read = seq_read,
373 .llseek = seq_lseek,
374 .release = single_release,
375 };
376 #endif
377
378 static int __net_init ip_rt_do_proc_init(struct net *net)
379 {
380 struct proc_dir_entry *pde;
381
382 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
383 &rt_cache_seq_fops);
384 if (!pde)
385 goto err1;
386
387 pde = proc_create("rt_cache", S_IRUGO,
388 net->proc_net_stat, &rt_cpu_seq_fops);
389 if (!pde)
390 goto err2;
391
392 #ifdef CONFIG_IP_ROUTE_CLASSID
393 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
394 if (!pde)
395 goto err3;
396 #endif
397 return 0;
398
399 #ifdef CONFIG_IP_ROUTE_CLASSID
400 err3:
401 remove_proc_entry("rt_cache", net->proc_net_stat);
402 #endif
403 err2:
404 remove_proc_entry("rt_cache", net->proc_net);
405 err1:
406 return -ENOMEM;
407 }
408
409 static void __net_exit ip_rt_do_proc_exit(struct net *net)
410 {
411 remove_proc_entry("rt_cache", net->proc_net_stat);
412 remove_proc_entry("rt_cache", net->proc_net);
413 #ifdef CONFIG_IP_ROUTE_CLASSID
414 remove_proc_entry("rt_acct", net->proc_net);
415 #endif
416 }
417
418 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
419 .init = ip_rt_do_proc_init,
420 .exit = ip_rt_do_proc_exit,
421 };
422
423 static int __init ip_rt_proc_init(void)
424 {
425 return register_pernet_subsys(&ip_rt_proc_ops);
426 }
427
428 #else
429 static inline int ip_rt_proc_init(void)
430 {
431 return 0;
432 }
433 #endif /* CONFIG_PROC_FS */
434
435 static inline bool rt_is_expired(const struct rtable *rth)
436 {
437 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
438 }
439
440 void rt_cache_flush(struct net *net)
441 {
442 rt_genid_bump_ipv4(net);
443 }
444
445 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
446 struct sk_buff *skb,
447 const void *daddr)
448 {
449 struct net_device *dev = dst->dev;
450 const __be32 *pkey = daddr;
451 const struct rtable *rt;
452 struct neighbour *n;
453
454 rt = (const struct rtable *) dst;
455 if (rt->rt_gateway)
456 pkey = (const __be32 *) &rt->rt_gateway;
457 else if (skb)
458 pkey = &ip_hdr(skb)->daddr;
459
460 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
461 if (n)
462 return n;
463 return neigh_create(&arp_tbl, pkey, dev);
464 }
465
466 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
467 {
468 struct net_device *dev = dst->dev;
469 const __be32 *pkey = daddr;
470 const struct rtable *rt;
471
472 rt = (const struct rtable *)dst;
473 if (rt->rt_gateway)
474 pkey = (const __be32 *)&rt->rt_gateway;
475 else if (!daddr ||
476 (rt->rt_flags &
477 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
478 return;
479
480 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
481 }
482
483 #define IP_IDENTS_SZ 2048u
484
485 static atomic_t *ip_idents __read_mostly;
486 static u32 *ip_tstamps __read_mostly;
487
488 /* In order to protect privacy, we add a perturbation to identifiers
489 * if one generator is seldom used. This makes hard for an attacker
490 * to infer how many packets were sent between two points in time.
491 */
492 u32 ip_idents_reserve(u32 hash, int segs)
493 {
494 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
495 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
496 u32 old = ACCESS_ONCE(*p_tstamp);
497 u32 now = (u32)jiffies;
498 u32 new, delta = 0;
499
500 if (old != now && cmpxchg(p_tstamp, old, now) == old)
501 delta = prandom_u32_max(now - old);
502
503 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
504 do {
505 old = (u32)atomic_read(p_id);
506 new = old + delta + segs;
507 } while (atomic_cmpxchg(p_id, old, new) != old);
508
509 return new - segs;
510 }
511 EXPORT_SYMBOL(ip_idents_reserve);
512
513 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
514 {
515 static u32 ip_idents_hashrnd __read_mostly;
516 u32 hash, id;
517
518 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
519
520 hash = jhash_3words((__force u32)iph->daddr,
521 (__force u32)iph->saddr,
522 iph->protocol ^ net_hash_mix(net),
523 ip_idents_hashrnd);
524 id = ip_idents_reserve(hash, segs);
525 iph->id = htons(id);
526 }
527 EXPORT_SYMBOL(__ip_select_ident);
528
529 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
530 const struct sock *sk,
531 const struct iphdr *iph,
532 int oif, u8 tos,
533 u8 prot, u32 mark, int flow_flags)
534 {
535 if (sk) {
536 const struct inet_sock *inet = inet_sk(sk);
537
538 oif = sk->sk_bound_dev_if;
539 mark = sk->sk_mark;
540 tos = RT_CONN_FLAGS(sk);
541 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
542 }
543 flowi4_init_output(fl4, oif, mark, tos,
544 RT_SCOPE_UNIVERSE, prot,
545 flow_flags,
546 iph->daddr, iph->saddr, 0, 0,
547 sock_net_uid(net, sk));
548 }
549
550 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
551 const struct sock *sk)
552 {
553 const struct net *net = dev_net(skb->dev);
554 const struct iphdr *iph = ip_hdr(skb);
555 int oif = skb->dev->ifindex;
556 u8 tos = RT_TOS(iph->tos);
557 u8 prot = iph->protocol;
558 u32 mark = skb->mark;
559
560 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
561 }
562
563 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
564 {
565 const struct inet_sock *inet = inet_sk(sk);
566 const struct ip_options_rcu *inet_opt;
567 __be32 daddr = inet->inet_daddr;
568
569 rcu_read_lock();
570 inet_opt = rcu_dereference(inet->inet_opt);
571 if (inet_opt && inet_opt->opt.srr)
572 daddr = inet_opt->opt.faddr;
573 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
574 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
575 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
576 inet_sk_flowi_flags(sk),
577 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
578 rcu_read_unlock();
579 }
580
581 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
582 const struct sk_buff *skb)
583 {
584 if (skb)
585 build_skb_flow_key(fl4, skb, sk);
586 else
587 build_sk_flow_key(fl4, sk);
588 }
589
590 static inline void rt_free(struct rtable *rt)
591 {
592 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
593 }
594
595 static DEFINE_SPINLOCK(fnhe_lock);
596
597 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
598 {
599 struct rtable *rt;
600
601 rt = rcu_dereference(fnhe->fnhe_rth_input);
602 if (rt) {
603 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
604 rt_free(rt);
605 }
606 rt = rcu_dereference(fnhe->fnhe_rth_output);
607 if (rt) {
608 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
609 rt_free(rt);
610 }
611 }
612
613 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
614 {
615 struct fib_nh_exception *fnhe, *oldest;
616
617 oldest = rcu_dereference(hash->chain);
618 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
619 fnhe = rcu_dereference(fnhe->fnhe_next)) {
620 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
621 oldest = fnhe;
622 }
623 fnhe_flush_routes(oldest);
624 return oldest;
625 }
626
627 static inline u32 fnhe_hashfun(__be32 daddr)
628 {
629 static u32 fnhe_hashrnd __read_mostly;
630 u32 hval;
631
632 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
633 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
634 return hash_32(hval, FNHE_HASH_SHIFT);
635 }
636
637 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
638 {
639 rt->rt_pmtu = fnhe->fnhe_pmtu;
640 rt->dst.expires = fnhe->fnhe_expires;
641
642 if (fnhe->fnhe_gw) {
643 rt->rt_flags |= RTCF_REDIRECTED;
644 rt->rt_gateway = fnhe->fnhe_gw;
645 rt->rt_uses_gateway = 1;
646 }
647 }
648
649 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
650 u32 pmtu, unsigned long expires)
651 {
652 struct fnhe_hash_bucket *hash;
653 struct fib_nh_exception *fnhe;
654 struct rtable *rt;
655 unsigned int i;
656 int depth;
657 u32 hval = fnhe_hashfun(daddr);
658
659 spin_lock_bh(&fnhe_lock);
660
661 hash = rcu_dereference(nh->nh_exceptions);
662 if (!hash) {
663 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
664 if (!hash)
665 goto out_unlock;
666 rcu_assign_pointer(nh->nh_exceptions, hash);
667 }
668
669 hash += hval;
670
671 depth = 0;
672 for (fnhe = rcu_dereference(hash->chain); fnhe;
673 fnhe = rcu_dereference(fnhe->fnhe_next)) {
674 if (fnhe->fnhe_daddr == daddr)
675 break;
676 depth++;
677 }
678
679 if (fnhe) {
680 if (gw)
681 fnhe->fnhe_gw = gw;
682 if (pmtu) {
683 fnhe->fnhe_pmtu = pmtu;
684 fnhe->fnhe_expires = max(1UL, expires);
685 }
686 /* Update all cached dsts too */
687 rt = rcu_dereference(fnhe->fnhe_rth_input);
688 if (rt)
689 fill_route_from_fnhe(rt, fnhe);
690 rt = rcu_dereference(fnhe->fnhe_rth_output);
691 if (rt)
692 fill_route_from_fnhe(rt, fnhe);
693 } else {
694 if (depth > FNHE_RECLAIM_DEPTH)
695 fnhe = fnhe_oldest(hash);
696 else {
697 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
698 if (!fnhe)
699 goto out_unlock;
700
701 fnhe->fnhe_next = hash->chain;
702 rcu_assign_pointer(hash->chain, fnhe);
703 }
704 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
705 fnhe->fnhe_daddr = daddr;
706 fnhe->fnhe_gw = gw;
707 fnhe->fnhe_pmtu = pmtu;
708 fnhe->fnhe_expires = expires;
709
710 /* Exception created; mark the cached routes for the nexthop
711 * stale, so anyone caching it rechecks if this exception
712 * applies to them.
713 */
714 rt = rcu_dereference(nh->nh_rth_input);
715 if (rt)
716 rt->dst.obsolete = DST_OBSOLETE_KILL;
717
718 for_each_possible_cpu(i) {
719 struct rtable __rcu **prt;
720 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
721 rt = rcu_dereference(*prt);
722 if (rt)
723 rt->dst.obsolete = DST_OBSOLETE_KILL;
724 }
725 }
726
727 fnhe->fnhe_stamp = jiffies;
728
729 out_unlock:
730 spin_unlock_bh(&fnhe_lock);
731 }
732
733 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
734 bool kill_route)
735 {
736 __be32 new_gw = icmp_hdr(skb)->un.gateway;
737 __be32 old_gw = ip_hdr(skb)->saddr;
738 struct net_device *dev = skb->dev;
739 struct in_device *in_dev;
740 struct fib_result res;
741 struct neighbour *n;
742 struct net *net;
743
744 switch (icmp_hdr(skb)->code & 7) {
745 case ICMP_REDIR_NET:
746 case ICMP_REDIR_NETTOS:
747 case ICMP_REDIR_HOST:
748 case ICMP_REDIR_HOSTTOS:
749 break;
750
751 default:
752 return;
753 }
754
755 if (rt->rt_gateway != old_gw)
756 return;
757
758 in_dev = __in_dev_get_rcu(dev);
759 if (!in_dev)
760 return;
761
762 net = dev_net(dev);
763 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
764 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
765 ipv4_is_zeronet(new_gw))
766 goto reject_redirect;
767
768 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
769 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
770 goto reject_redirect;
771 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
772 goto reject_redirect;
773 } else {
774 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
775 goto reject_redirect;
776 }
777
778 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
779 if (!n)
780 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
781 if (!IS_ERR(n)) {
782 if (!(n->nud_state & NUD_VALID)) {
783 neigh_event_send(n, NULL);
784 } else {
785 if (fib_lookup(net, fl4, &res, 0) == 0) {
786 struct fib_nh *nh = &FIB_RES_NH(res);
787
788 update_or_create_fnhe(nh, fl4->daddr, new_gw,
789 0, jiffies + ip_rt_gc_timeout);
790 }
791 if (kill_route)
792 rt->dst.obsolete = DST_OBSOLETE_KILL;
793 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
794 }
795 neigh_release(n);
796 }
797 return;
798
799 reject_redirect:
800 #ifdef CONFIG_IP_ROUTE_VERBOSE
801 if (IN_DEV_LOG_MARTIANS(in_dev)) {
802 const struct iphdr *iph = (const struct iphdr *) skb->data;
803 __be32 daddr = iph->daddr;
804 __be32 saddr = iph->saddr;
805
806 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
807 " Advised path = %pI4 -> %pI4\n",
808 &old_gw, dev->name, &new_gw,
809 &saddr, &daddr);
810 }
811 #endif
812 ;
813 }
814
815 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
816 {
817 struct rtable *rt;
818 struct flowi4 fl4;
819 const struct iphdr *iph = (const struct iphdr *) skb->data;
820 struct net *net = dev_net(skb->dev);
821 int oif = skb->dev->ifindex;
822 u8 tos = RT_TOS(iph->tos);
823 u8 prot = iph->protocol;
824 u32 mark = skb->mark;
825
826 rt = (struct rtable *) dst;
827
828 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
829 __ip_do_redirect(rt, skb, &fl4, true);
830 }
831
832 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
833 {
834 struct rtable *rt = (struct rtable *)dst;
835 struct dst_entry *ret = dst;
836
837 if (rt) {
838 if (dst->obsolete > 0) {
839 ip_rt_put(rt);
840 ret = NULL;
841 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
842 rt->dst.expires) {
843 ip_rt_put(rt);
844 ret = NULL;
845 }
846 }
847 return ret;
848 }
849
850 /*
851 * Algorithm:
852 * 1. The first ip_rt_redirect_number redirects are sent
853 * with exponential backoff, then we stop sending them at all,
854 * assuming that the host ignores our redirects.
855 * 2. If we did not see packets requiring redirects
856 * during ip_rt_redirect_silence, we assume that the host
857 * forgot redirected route and start to send redirects again.
858 *
859 * This algorithm is much cheaper and more intelligent than dumb load limiting
860 * in icmp.c.
861 *
862 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
863 * and "frag. need" (breaks PMTU discovery) in icmp.c.
864 */
865
866 void ip_rt_send_redirect(struct sk_buff *skb)
867 {
868 struct rtable *rt = skb_rtable(skb);
869 struct in_device *in_dev;
870 struct inet_peer *peer;
871 struct net *net;
872 int log_martians;
873 int vif;
874
875 rcu_read_lock();
876 in_dev = __in_dev_get_rcu(rt->dst.dev);
877 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
878 rcu_read_unlock();
879 return;
880 }
881 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
882 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
883 rcu_read_unlock();
884
885 net = dev_net(rt->dst.dev);
886 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
887 if (!peer) {
888 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
889 rt_nexthop(rt, ip_hdr(skb)->daddr));
890 return;
891 }
892
893 /* No redirected packets during ip_rt_redirect_silence;
894 * reset the algorithm.
895 */
896 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
897 peer->rate_tokens = 0;
898
899 /* Too many ignored redirects; do not send anything
900 * set dst.rate_last to the last seen redirected packet.
901 */
902 if (peer->rate_tokens >= ip_rt_redirect_number) {
903 peer->rate_last = jiffies;
904 goto out_put_peer;
905 }
906
907 /* Check for load limit; set rate_last to the latest sent
908 * redirect.
909 */
910 if (peer->rate_tokens == 0 ||
911 time_after(jiffies,
912 (peer->rate_last +
913 (ip_rt_redirect_load << peer->rate_tokens)))) {
914 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
915
916 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
917 peer->rate_last = jiffies;
918 ++peer->rate_tokens;
919 #ifdef CONFIG_IP_ROUTE_VERBOSE
920 if (log_martians &&
921 peer->rate_tokens == ip_rt_redirect_number)
922 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
923 &ip_hdr(skb)->saddr, inet_iif(skb),
924 &ip_hdr(skb)->daddr, &gw);
925 #endif
926 }
927 out_put_peer:
928 inet_putpeer(peer);
929 }
930
931 static int ip_error(struct sk_buff *skb)
932 {
933 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
934 struct rtable *rt = skb_rtable(skb);
935 struct inet_peer *peer;
936 unsigned long now;
937 struct net *net;
938 bool send;
939 int code;
940
941 /* IP on this device is disabled. */
942 if (!in_dev)
943 goto out;
944
945 net = dev_net(rt->dst.dev);
946 if (!IN_DEV_FORWARD(in_dev)) {
947 switch (rt->dst.error) {
948 case EHOSTUNREACH:
949 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
950 break;
951
952 case ENETUNREACH:
953 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
954 break;
955 }
956 goto out;
957 }
958
959 switch (rt->dst.error) {
960 case EINVAL:
961 default:
962 goto out;
963 case EHOSTUNREACH:
964 code = ICMP_HOST_UNREACH;
965 break;
966 case ENETUNREACH:
967 code = ICMP_NET_UNREACH;
968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
969 break;
970 case EACCES:
971 code = ICMP_PKT_FILTERED;
972 break;
973 }
974
975 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
976 l3mdev_master_ifindex(skb->dev), 1);
977
978 send = true;
979 if (peer) {
980 now = jiffies;
981 peer->rate_tokens += now - peer->rate_last;
982 if (peer->rate_tokens > ip_rt_error_burst)
983 peer->rate_tokens = ip_rt_error_burst;
984 peer->rate_last = now;
985 if (peer->rate_tokens >= ip_rt_error_cost)
986 peer->rate_tokens -= ip_rt_error_cost;
987 else
988 send = false;
989 inet_putpeer(peer);
990 }
991 if (send)
992 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
993
994 out: kfree_skb(skb);
995 return 0;
996 }
997
998 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
999 {
1000 struct dst_entry *dst = &rt->dst;
1001 struct fib_result res;
1002
1003 if (dst_metric_locked(dst, RTAX_MTU))
1004 return;
1005
1006 if (ipv4_mtu(dst) < mtu)
1007 return;
1008
1009 if (mtu < ip_rt_min_pmtu)
1010 mtu = ip_rt_min_pmtu;
1011
1012 if (rt->rt_pmtu == mtu &&
1013 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1014 return;
1015
1016 rcu_read_lock();
1017 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1018 struct fib_nh *nh = &FIB_RES_NH(res);
1019
1020 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
1021 jiffies + ip_rt_mtu_expires);
1022 }
1023 rcu_read_unlock();
1024 }
1025
1026 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1027 struct sk_buff *skb, u32 mtu)
1028 {
1029 struct rtable *rt = (struct rtable *) dst;
1030 struct flowi4 fl4;
1031
1032 ip_rt_build_flow_key(&fl4, sk, skb);
1033 __ip_rt_update_pmtu(rt, &fl4, mtu);
1034 }
1035
1036 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1037 int oif, u32 mark, u8 protocol, int flow_flags)
1038 {
1039 const struct iphdr *iph = (const struct iphdr *) skb->data;
1040 struct flowi4 fl4;
1041 struct rtable *rt;
1042
1043 if (!mark)
1044 mark = IP4_REPLY_MARK(net, skb->mark);
1045
1046 __build_flow_key(net, &fl4, NULL, iph, oif,
1047 RT_TOS(iph->tos), protocol, mark, flow_flags);
1048 rt = __ip_route_output_key(net, &fl4);
1049 if (!IS_ERR(rt)) {
1050 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 ip_rt_put(rt);
1052 }
1053 }
1054 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1055
1056 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1057 {
1058 const struct iphdr *iph = (const struct iphdr *) skb->data;
1059 struct flowi4 fl4;
1060 struct rtable *rt;
1061
1062 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1063
1064 if (!fl4.flowi4_mark)
1065 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1066
1067 rt = __ip_route_output_key(sock_net(sk), &fl4);
1068 if (!IS_ERR(rt)) {
1069 __ip_rt_update_pmtu(rt, &fl4, mtu);
1070 ip_rt_put(rt);
1071 }
1072 }
1073
1074 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1075 {
1076 const struct iphdr *iph = (const struct iphdr *) skb->data;
1077 struct flowi4 fl4;
1078 struct rtable *rt;
1079 struct dst_entry *odst = NULL;
1080 bool new = false;
1081 struct net *net = sock_net(sk);
1082
1083 bh_lock_sock(sk);
1084
1085 if (!ip_sk_accept_pmtu(sk))
1086 goto out;
1087
1088 odst = sk_dst_get(sk);
1089
1090 if (sock_owned_by_user(sk) || !odst) {
1091 __ipv4_sk_update_pmtu(skb, sk, mtu);
1092 goto out;
1093 }
1094
1095 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1096
1097 rt = (struct rtable *)odst;
1098 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1099 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1100 if (IS_ERR(rt))
1101 goto out;
1102
1103 new = true;
1104 }
1105
1106 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1107
1108 if (!dst_check(&rt->dst, 0)) {
1109 if (new)
1110 dst_release(&rt->dst);
1111
1112 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1113 if (IS_ERR(rt))
1114 goto out;
1115
1116 new = true;
1117 }
1118
1119 if (new)
1120 sk_dst_set(sk, &rt->dst);
1121
1122 out:
1123 bh_unlock_sock(sk);
1124 dst_release(odst);
1125 }
1126 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1127
1128 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1129 int oif, u32 mark, u8 protocol, int flow_flags)
1130 {
1131 const struct iphdr *iph = (const struct iphdr *) skb->data;
1132 struct flowi4 fl4;
1133 struct rtable *rt;
1134
1135 __build_flow_key(net, &fl4, NULL, iph, oif,
1136 RT_TOS(iph->tos), protocol, mark, flow_flags);
1137 rt = __ip_route_output_key(net, &fl4);
1138 if (!IS_ERR(rt)) {
1139 __ip_do_redirect(rt, skb, &fl4, false);
1140 ip_rt_put(rt);
1141 }
1142 }
1143 EXPORT_SYMBOL_GPL(ipv4_redirect);
1144
1145 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1146 {
1147 const struct iphdr *iph = (const struct iphdr *) skb->data;
1148 struct flowi4 fl4;
1149 struct rtable *rt;
1150 struct net *net = sock_net(sk);
1151
1152 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1153 rt = __ip_route_output_key(net, &fl4);
1154 if (!IS_ERR(rt)) {
1155 __ip_do_redirect(rt, skb, &fl4, false);
1156 ip_rt_put(rt);
1157 }
1158 }
1159 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1160
1161 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1162 {
1163 struct rtable *rt = (struct rtable *) dst;
1164
1165 /* All IPV4 dsts are created with ->obsolete set to the value
1166 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1167 * into this function always.
1168 *
1169 * When a PMTU/redirect information update invalidates a route,
1170 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1171 * DST_OBSOLETE_DEAD by dst_free().
1172 */
1173 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1174 return NULL;
1175 return dst;
1176 }
1177
1178 static void ipv4_link_failure(struct sk_buff *skb)
1179 {
1180 struct rtable *rt;
1181
1182 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1183
1184 rt = skb_rtable(skb);
1185 if (rt)
1186 dst_set_expires(&rt->dst, 0);
1187 }
1188
1189 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1190 {
1191 pr_debug("%s: %pI4 -> %pI4, %s\n",
1192 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1193 skb->dev ? skb->dev->name : "?");
1194 kfree_skb(skb);
1195 WARN_ON(1);
1196 return 0;
1197 }
1198
1199 /*
1200 We do not cache source address of outgoing interface,
1201 because it is used only by IP RR, TS and SRR options,
1202 so that it out of fast path.
1203
1204 BTW remember: "addr" is allowed to be not aligned
1205 in IP options!
1206 */
1207
1208 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1209 {
1210 __be32 src;
1211
1212 if (rt_is_output_route(rt))
1213 src = ip_hdr(skb)->saddr;
1214 else {
1215 struct fib_result res;
1216 struct flowi4 fl4;
1217 struct iphdr *iph;
1218
1219 iph = ip_hdr(skb);
1220
1221 memset(&fl4, 0, sizeof(fl4));
1222 fl4.daddr = iph->daddr;
1223 fl4.saddr = iph->saddr;
1224 fl4.flowi4_tos = RT_TOS(iph->tos);
1225 fl4.flowi4_oif = rt->dst.dev->ifindex;
1226 fl4.flowi4_iif = skb->dev->ifindex;
1227 fl4.flowi4_mark = skb->mark;
1228
1229 rcu_read_lock();
1230 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1231 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1232 else
1233 src = inet_select_addr(rt->dst.dev,
1234 rt_nexthop(rt, iph->daddr),
1235 RT_SCOPE_UNIVERSE);
1236 rcu_read_unlock();
1237 }
1238 memcpy(addr, &src, 4);
1239 }
1240
1241 #ifdef CONFIG_IP_ROUTE_CLASSID
1242 static void set_class_tag(struct rtable *rt, u32 tag)
1243 {
1244 if (!(rt->dst.tclassid & 0xFFFF))
1245 rt->dst.tclassid |= tag & 0xFFFF;
1246 if (!(rt->dst.tclassid & 0xFFFF0000))
1247 rt->dst.tclassid |= tag & 0xFFFF0000;
1248 }
1249 #endif
1250
1251 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1252 {
1253 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1254 unsigned int advmss = max_t(unsigned int, dst->dev->mtu - header_size,
1255 ip_rt_min_advmss);
1256
1257 return min(advmss, IPV4_MAX_PMTU - header_size);
1258 }
1259
1260 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1261 {
1262 const struct rtable *rt = (const struct rtable *) dst;
1263 unsigned int mtu = rt->rt_pmtu;
1264
1265 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1266 mtu = dst_metric_raw(dst, RTAX_MTU);
1267
1268 if (mtu)
1269 return mtu;
1270
1271 mtu = dst->dev->mtu;
1272
1273 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1274 if (rt->rt_uses_gateway && mtu > 576)
1275 mtu = 576;
1276 }
1277
1278 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1279
1280 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1281 }
1282
1283 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1284 {
1285 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1286 struct fib_nh_exception *fnhe;
1287 u32 hval;
1288
1289 if (!hash)
1290 return NULL;
1291
1292 hval = fnhe_hashfun(daddr);
1293
1294 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1295 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1296 if (fnhe->fnhe_daddr == daddr)
1297 return fnhe;
1298 }
1299 return NULL;
1300 }
1301
1302 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1303 __be32 daddr)
1304 {
1305 bool ret = false;
1306
1307 spin_lock_bh(&fnhe_lock);
1308
1309 if (daddr == fnhe->fnhe_daddr) {
1310 struct rtable __rcu **porig;
1311 struct rtable *orig;
1312 int genid = fnhe_genid(dev_net(rt->dst.dev));
1313
1314 if (rt_is_input_route(rt))
1315 porig = &fnhe->fnhe_rth_input;
1316 else
1317 porig = &fnhe->fnhe_rth_output;
1318 orig = rcu_dereference(*porig);
1319
1320 if (fnhe->fnhe_genid != genid) {
1321 fnhe->fnhe_genid = genid;
1322 fnhe->fnhe_gw = 0;
1323 fnhe->fnhe_pmtu = 0;
1324 fnhe->fnhe_expires = 0;
1325 fnhe_flush_routes(fnhe);
1326 orig = NULL;
1327 }
1328 fill_route_from_fnhe(rt, fnhe);
1329 if (!rt->rt_gateway)
1330 rt->rt_gateway = daddr;
1331
1332 if (!(rt->dst.flags & DST_NOCACHE)) {
1333 rcu_assign_pointer(*porig, rt);
1334 if (orig)
1335 rt_free(orig);
1336 ret = true;
1337 }
1338
1339 fnhe->fnhe_stamp = jiffies;
1340 }
1341 spin_unlock_bh(&fnhe_lock);
1342
1343 return ret;
1344 }
1345
1346 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1347 {
1348 struct rtable *orig, *prev, **p;
1349 bool ret = true;
1350
1351 if (rt_is_input_route(rt)) {
1352 p = (struct rtable **)&nh->nh_rth_input;
1353 } else {
1354 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1355 }
1356 orig = *p;
1357
1358 prev = cmpxchg(p, orig, rt);
1359 if (prev == orig) {
1360 if (orig)
1361 rt_free(orig);
1362 } else
1363 ret = false;
1364
1365 return ret;
1366 }
1367
1368 struct uncached_list {
1369 spinlock_t lock;
1370 struct list_head head;
1371 };
1372
1373 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1374
1375 static void rt_add_uncached_list(struct rtable *rt)
1376 {
1377 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1378
1379 rt->rt_uncached_list = ul;
1380
1381 spin_lock_bh(&ul->lock);
1382 list_add_tail(&rt->rt_uncached, &ul->head);
1383 spin_unlock_bh(&ul->lock);
1384 }
1385
1386 static void ipv4_dst_destroy(struct dst_entry *dst)
1387 {
1388 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1389 struct rtable *rt = (struct rtable *) dst;
1390
1391 if (p != &dst_default_metrics && atomic_dec_and_test(&p->refcnt))
1392 kfree(p);
1393
1394 if (!list_empty(&rt->rt_uncached)) {
1395 struct uncached_list *ul = rt->rt_uncached_list;
1396
1397 spin_lock_bh(&ul->lock);
1398 list_del(&rt->rt_uncached);
1399 spin_unlock_bh(&ul->lock);
1400 }
1401 }
1402
1403 void rt_flush_dev(struct net_device *dev)
1404 {
1405 struct net *net = dev_net(dev);
1406 struct rtable *rt;
1407 int cpu;
1408
1409 for_each_possible_cpu(cpu) {
1410 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1411
1412 spin_lock_bh(&ul->lock);
1413 list_for_each_entry(rt, &ul->head, rt_uncached) {
1414 if (rt->dst.dev != dev)
1415 continue;
1416 rt->dst.dev = net->loopback_dev;
1417 dev_hold(rt->dst.dev);
1418 dev_put(dev);
1419 }
1420 spin_unlock_bh(&ul->lock);
1421 }
1422 }
1423
1424 static bool rt_cache_valid(const struct rtable *rt)
1425 {
1426 return rt &&
1427 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1428 !rt_is_expired(rt);
1429 }
1430
1431 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1432 const struct fib_result *res,
1433 struct fib_nh_exception *fnhe,
1434 struct fib_info *fi, u16 type, u32 itag)
1435 {
1436 bool cached = false;
1437
1438 if (fi) {
1439 struct fib_nh *nh = &FIB_RES_NH(*res);
1440
1441 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1442 rt->rt_gateway = nh->nh_gw;
1443 rt->rt_uses_gateway = 1;
1444 }
1445 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1446 if (fi->fib_metrics != &dst_default_metrics) {
1447 rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1448 atomic_inc(&fi->fib_metrics->refcnt);
1449 }
1450 #ifdef CONFIG_IP_ROUTE_CLASSID
1451 rt->dst.tclassid = nh->nh_tclassid;
1452 #endif
1453 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1454 if (unlikely(fnhe))
1455 cached = rt_bind_exception(rt, fnhe, daddr);
1456 else if (!(rt->dst.flags & DST_NOCACHE))
1457 cached = rt_cache_route(nh, rt);
1458 if (unlikely(!cached)) {
1459 /* Routes we intend to cache in nexthop exception or
1460 * FIB nexthop have the DST_NOCACHE bit clear.
1461 * However, if we are unsuccessful at storing this
1462 * route into the cache we really need to set it.
1463 */
1464 rt->dst.flags |= DST_NOCACHE;
1465 if (!rt->rt_gateway)
1466 rt->rt_gateway = daddr;
1467 rt_add_uncached_list(rt);
1468 }
1469 } else
1470 rt_add_uncached_list(rt);
1471
1472 #ifdef CONFIG_IP_ROUTE_CLASSID
1473 #ifdef CONFIG_IP_MULTIPLE_TABLES
1474 set_class_tag(rt, res->tclassid);
1475 #endif
1476 set_class_tag(rt, itag);
1477 #endif
1478 }
1479
1480 struct rtable *rt_dst_alloc(struct net_device *dev,
1481 unsigned int flags, u16 type,
1482 bool nopolicy, bool noxfrm, bool will_cache)
1483 {
1484 struct rtable *rt;
1485
1486 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1487 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1488 (nopolicy ? DST_NOPOLICY : 0) |
1489 (noxfrm ? DST_NOXFRM : 0));
1490
1491 if (rt) {
1492 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1493 rt->rt_flags = flags;
1494 rt->rt_type = type;
1495 rt->rt_is_input = 0;
1496 rt->rt_iif = 0;
1497 rt->rt_pmtu = 0;
1498 rt->rt_gateway = 0;
1499 rt->rt_uses_gateway = 0;
1500 rt->rt_table_id = 0;
1501 INIT_LIST_HEAD(&rt->rt_uncached);
1502
1503 rt->dst.output = ip_output;
1504 if (flags & RTCF_LOCAL)
1505 rt->dst.input = ip_local_deliver;
1506 }
1507
1508 return rt;
1509 }
1510 EXPORT_SYMBOL(rt_dst_alloc);
1511
1512 /* called in rcu_read_lock() section */
1513 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1514 u8 tos, struct net_device *dev, int our)
1515 {
1516 struct rtable *rth;
1517 struct in_device *in_dev = __in_dev_get_rcu(dev);
1518 unsigned int flags = RTCF_MULTICAST;
1519 u32 itag = 0;
1520 int err;
1521
1522 /* Primary sanity checks. */
1523
1524 if (!in_dev)
1525 return -EINVAL;
1526
1527 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1528 skb->protocol != htons(ETH_P_IP))
1529 goto e_inval;
1530
1531 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1532 goto e_inval;
1533
1534 if (ipv4_is_zeronet(saddr)) {
1535 if (!ipv4_is_local_multicast(daddr))
1536 goto e_inval;
1537 } else {
1538 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1539 in_dev, &itag);
1540 if (err < 0)
1541 goto e_err;
1542 }
1543 if (our)
1544 flags |= RTCF_LOCAL;
1545
1546 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1547 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1548 if (!rth)
1549 goto e_nobufs;
1550
1551 #ifdef CONFIG_IP_ROUTE_CLASSID
1552 rth->dst.tclassid = itag;
1553 #endif
1554 rth->dst.output = ip_rt_bug;
1555 rth->rt_is_input= 1;
1556
1557 #ifdef CONFIG_IP_MROUTE
1558 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1559 rth->dst.input = ip_mr_input;
1560 #endif
1561 RT_CACHE_STAT_INC(in_slow_mc);
1562
1563 skb_dst_set(skb, &rth->dst);
1564 return 0;
1565
1566 e_nobufs:
1567 return -ENOBUFS;
1568 e_inval:
1569 return -EINVAL;
1570 e_err:
1571 return err;
1572 }
1573
1574
1575 static void ip_handle_martian_source(struct net_device *dev,
1576 struct in_device *in_dev,
1577 struct sk_buff *skb,
1578 __be32 daddr,
1579 __be32 saddr)
1580 {
1581 RT_CACHE_STAT_INC(in_martian_src);
1582 #ifdef CONFIG_IP_ROUTE_VERBOSE
1583 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1584 /*
1585 * RFC1812 recommendation, if source is martian,
1586 * the only hint is MAC header.
1587 */
1588 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1589 &daddr, &saddr, dev->name);
1590 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1591 print_hex_dump(KERN_WARNING, "ll header: ",
1592 DUMP_PREFIX_OFFSET, 16, 1,
1593 skb_mac_header(skb),
1594 dev->hard_header_len, true);
1595 }
1596 }
1597 #endif
1598 }
1599
1600 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1601 {
1602 struct fnhe_hash_bucket *hash;
1603 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1604 u32 hval = fnhe_hashfun(daddr);
1605
1606 spin_lock_bh(&fnhe_lock);
1607
1608 hash = rcu_dereference_protected(nh->nh_exceptions,
1609 lockdep_is_held(&fnhe_lock));
1610 hash += hval;
1611
1612 fnhe_p = &hash->chain;
1613 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1614 while (fnhe) {
1615 if (fnhe->fnhe_daddr == daddr) {
1616 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1617 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1618 fnhe_flush_routes(fnhe);
1619 kfree_rcu(fnhe, rcu);
1620 break;
1621 }
1622 fnhe_p = &fnhe->fnhe_next;
1623 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1624 lockdep_is_held(&fnhe_lock));
1625 }
1626
1627 spin_unlock_bh(&fnhe_lock);
1628 }
1629
1630 static void set_lwt_redirect(struct rtable *rth)
1631 {
1632 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1633 rth->dst.lwtstate->orig_output = rth->dst.output;
1634 rth->dst.output = lwtunnel_output;
1635 }
1636
1637 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1638 rth->dst.lwtstate->orig_input = rth->dst.input;
1639 rth->dst.input = lwtunnel_input;
1640 }
1641 }
1642
1643 /* called in rcu_read_lock() section */
1644 static int __mkroute_input(struct sk_buff *skb,
1645 const struct fib_result *res,
1646 struct in_device *in_dev,
1647 __be32 daddr, __be32 saddr, u32 tos)
1648 {
1649 struct fib_nh_exception *fnhe;
1650 struct rtable *rth;
1651 int err;
1652 struct in_device *out_dev;
1653 bool do_cache;
1654 u32 itag = 0;
1655
1656 /* get a working reference to the output device */
1657 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1658 if (!out_dev) {
1659 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1660 return -EINVAL;
1661 }
1662
1663 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1664 in_dev->dev, in_dev, &itag);
1665 if (err < 0) {
1666 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1667 saddr);
1668
1669 goto cleanup;
1670 }
1671
1672 do_cache = res->fi && !itag;
1673 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1674 skb->protocol == htons(ETH_P_IP) &&
1675 (IN_DEV_SHARED_MEDIA(out_dev) ||
1676 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1677 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1678
1679 if (skb->protocol != htons(ETH_P_IP)) {
1680 /* Not IP (i.e. ARP). Do not create route, if it is
1681 * invalid for proxy arp. DNAT routes are always valid.
1682 *
1683 * Proxy arp feature have been extended to allow, ARP
1684 * replies back to the same interface, to support
1685 * Private VLAN switch technologies. See arp.c.
1686 */
1687 if (out_dev == in_dev &&
1688 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1689 err = -EINVAL;
1690 goto cleanup;
1691 }
1692 }
1693
1694 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1695 if (do_cache) {
1696 if (fnhe) {
1697 rth = rcu_dereference(fnhe->fnhe_rth_input);
1698 if (rth && rth->dst.expires &&
1699 time_after(jiffies, rth->dst.expires)) {
1700 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1701 fnhe = NULL;
1702 } else {
1703 goto rt_cache;
1704 }
1705 }
1706
1707 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1708
1709 rt_cache:
1710 if (rt_cache_valid(rth)) {
1711 skb_dst_set_noref(skb, &rth->dst);
1712 goto out;
1713 }
1714 }
1715
1716 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1717 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1718 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1719 if (!rth) {
1720 err = -ENOBUFS;
1721 goto cleanup;
1722 }
1723
1724 rth->rt_is_input = 1;
1725 if (res->table)
1726 rth->rt_table_id = res->table->tb_id;
1727 RT_CACHE_STAT_INC(in_slow_tot);
1728
1729 rth->dst.input = ip_forward;
1730
1731 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1732 set_lwt_redirect(rth);
1733 skb_dst_set(skb, &rth->dst);
1734 out:
1735 err = 0;
1736 cleanup:
1737 return err;
1738 }
1739
1740 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1741 /* To make ICMP packets follow the right flow, the multipath hash is
1742 * calculated from the inner IP addresses.
1743 */
1744 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1745 struct flow_keys *hash_keys)
1746 {
1747 const struct iphdr *outer_iph = ip_hdr(skb);
1748 const struct iphdr *inner_iph;
1749 const struct icmphdr *icmph;
1750 struct iphdr _inner_iph;
1751 struct icmphdr _icmph;
1752
1753 hash_keys->addrs.v4addrs.src = outer_iph->saddr;
1754 hash_keys->addrs.v4addrs.dst = outer_iph->daddr;
1755 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1756 return;
1757
1758 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1759 return;
1760
1761 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1762 &_icmph);
1763 if (!icmph)
1764 return;
1765
1766 if (icmph->type != ICMP_DEST_UNREACH &&
1767 icmph->type != ICMP_REDIRECT &&
1768 icmph->type != ICMP_TIME_EXCEEDED &&
1769 icmph->type != ICMP_PARAMETERPROB)
1770 return;
1771
1772 inner_iph = skb_header_pointer(skb,
1773 outer_iph->ihl * 4 + sizeof(_icmph),
1774 sizeof(_inner_iph), &_inner_iph);
1775 if (!inner_iph)
1776 return;
1777 hash_keys->addrs.v4addrs.src = inner_iph->saddr;
1778 hash_keys->addrs.v4addrs.dst = inner_iph->daddr;
1779 }
1780
1781 /* if skb is set it will be used and fl4 can be NULL */
1782 int fib_multipath_hash(const struct fib_info *fi, const struct flowi4 *fl4,
1783 const struct sk_buff *skb)
1784 {
1785 struct net *net = fi->fib_net;
1786 struct flow_keys hash_keys;
1787 u32 mhash;
1788
1789 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1790 case 0:
1791 memset(&hash_keys, 0, sizeof(hash_keys));
1792 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1793 if (skb) {
1794 ip_multipath_l3_keys(skb, &hash_keys);
1795 } else {
1796 hash_keys.addrs.v4addrs.src = fl4->saddr;
1797 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1798 }
1799 break;
1800 case 1:
1801 /* skb is currently provided only when forwarding */
1802 if (skb) {
1803 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1804 struct flow_keys keys;
1805
1806 /* short-circuit if we already have L4 hash present */
1807 if (skb->l4_hash)
1808 return skb_get_hash_raw(skb) >> 1;
1809 memset(&hash_keys, 0, sizeof(hash_keys));
1810 skb_flow_dissect_flow_keys(skb, &keys, flag);
1811 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1812 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1813 hash_keys.ports.src = keys.ports.src;
1814 hash_keys.ports.dst = keys.ports.dst;
1815 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1816 } else {
1817 memset(&hash_keys, 0, sizeof(hash_keys));
1818 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1819 hash_keys.addrs.v4addrs.src = fl4->saddr;
1820 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1821 hash_keys.ports.src = fl4->fl4_sport;
1822 hash_keys.ports.dst = fl4->fl4_dport;
1823 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1824 }
1825 break;
1826 }
1827 mhash = flow_hash_from_keys(&hash_keys);
1828
1829 return mhash >> 1;
1830 }
1831 EXPORT_SYMBOL_GPL(fib_multipath_hash);
1832 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1833
1834 static int ip_mkroute_input(struct sk_buff *skb,
1835 struct fib_result *res,
1836 struct in_device *in_dev,
1837 __be32 daddr, __be32 saddr, u32 tos)
1838 {
1839 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1840 if (res->fi && res->fi->fib_nhs > 1) {
1841 int h = fib_multipath_hash(res->fi, NULL, skb);
1842
1843 fib_select_multipath(res, h);
1844 }
1845 #endif
1846
1847 /* create a routing cache entry */
1848 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1849 }
1850
1851 /*
1852 * NOTE. We drop all the packets that has local source
1853 * addresses, because every properly looped back packet
1854 * must have correct destination already attached by output routine.
1855 *
1856 * Such approach solves two big problems:
1857 * 1. Not simplex devices are handled properly.
1858 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1859 * called with rcu_read_lock()
1860 */
1861
1862 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1863 u8 tos, struct net_device *dev)
1864 {
1865 struct fib_result res;
1866 struct in_device *in_dev = __in_dev_get_rcu(dev);
1867 struct ip_tunnel_info *tun_info;
1868 struct flowi4 fl4;
1869 unsigned int flags = 0;
1870 u32 itag = 0;
1871 struct rtable *rth;
1872 int err = -EINVAL;
1873 struct net *net = dev_net(dev);
1874 bool do_cache;
1875
1876 /* IP on this device is disabled. */
1877
1878 if (!in_dev)
1879 goto out;
1880
1881 /* Check for the most weird martians, which can be not detected
1882 by fib_lookup.
1883 */
1884
1885 tun_info = skb_tunnel_info(skb);
1886 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1887 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1888 else
1889 fl4.flowi4_tun_key.tun_id = 0;
1890 skb_dst_drop(skb);
1891
1892 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1893 goto martian_source;
1894
1895 res.fi = NULL;
1896 res.table = NULL;
1897 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1898 goto brd_input;
1899
1900 /* Accept zero addresses only to limited broadcast;
1901 * I even do not know to fix it or not. Waiting for complains :-)
1902 */
1903 if (ipv4_is_zeronet(saddr))
1904 goto martian_source;
1905
1906 if (ipv4_is_zeronet(daddr))
1907 goto martian_destination;
1908
1909 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1910 * and call it once if daddr or/and saddr are loopback addresses
1911 */
1912 if (ipv4_is_loopback(daddr)) {
1913 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1914 goto martian_destination;
1915 } else if (ipv4_is_loopback(saddr)) {
1916 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1917 goto martian_source;
1918 }
1919
1920 /*
1921 * Now we are ready to route packet.
1922 */
1923 fl4.flowi4_oif = 0;
1924 fl4.flowi4_iif = dev->ifindex;
1925 fl4.flowi4_mark = skb->mark;
1926 fl4.flowi4_tos = tos;
1927 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1928 fl4.flowi4_flags = 0;
1929 fl4.daddr = daddr;
1930 fl4.saddr = saddr;
1931 fl4.flowi4_uid = sock_net_uid(net, NULL);
1932 err = fib_lookup(net, &fl4, &res, 0);
1933 if (err != 0) {
1934 if (!IN_DEV_FORWARD(in_dev))
1935 err = -EHOSTUNREACH;
1936 goto no_route;
1937 }
1938
1939 if (res.type == RTN_BROADCAST)
1940 goto brd_input;
1941
1942 if (res.type == RTN_LOCAL) {
1943 err = fib_validate_source(skb, saddr, daddr, tos,
1944 0, dev, in_dev, &itag);
1945 if (err < 0)
1946 goto martian_source;
1947 goto local_input;
1948 }
1949
1950 if (!IN_DEV_FORWARD(in_dev)) {
1951 err = -EHOSTUNREACH;
1952 goto no_route;
1953 }
1954 if (res.type != RTN_UNICAST)
1955 goto martian_destination;
1956
1957 err = ip_mkroute_input(skb, &res, in_dev, daddr, saddr, tos);
1958 out: return err;
1959
1960 brd_input:
1961 if (skb->protocol != htons(ETH_P_IP))
1962 goto e_inval;
1963
1964 if (!ipv4_is_zeronet(saddr)) {
1965 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1966 in_dev, &itag);
1967 if (err < 0)
1968 goto martian_source;
1969 }
1970 flags |= RTCF_BROADCAST;
1971 res.type = RTN_BROADCAST;
1972 RT_CACHE_STAT_INC(in_brd);
1973
1974 local_input:
1975 do_cache = false;
1976 if (res.fi) {
1977 if (!itag) {
1978 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1979 if (rt_cache_valid(rth)) {
1980 skb_dst_set_noref(skb, &rth->dst);
1981 err = 0;
1982 goto out;
1983 }
1984 do_cache = true;
1985 }
1986 }
1987
1988 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
1989 flags | RTCF_LOCAL, res.type,
1990 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1991 if (!rth)
1992 goto e_nobufs;
1993
1994 rth->dst.output= ip_rt_bug;
1995 #ifdef CONFIG_IP_ROUTE_CLASSID
1996 rth->dst.tclassid = itag;
1997 #endif
1998 rth->rt_is_input = 1;
1999 if (res.table)
2000 rth->rt_table_id = res.table->tb_id;
2001
2002 RT_CACHE_STAT_INC(in_slow_tot);
2003 if (res.type == RTN_UNREACHABLE) {
2004 rth->dst.input= ip_error;
2005 rth->dst.error= -err;
2006 rth->rt_flags &= ~RTCF_LOCAL;
2007 }
2008
2009 if (do_cache) {
2010 struct fib_nh *nh = &FIB_RES_NH(res);
2011
2012 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2013 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2014 WARN_ON(rth->dst.input == lwtunnel_input);
2015 rth->dst.lwtstate->orig_input = rth->dst.input;
2016 rth->dst.input = lwtunnel_input;
2017 }
2018
2019 if (unlikely(!rt_cache_route(nh, rth))) {
2020 rth->dst.flags |= DST_NOCACHE;
2021 rt_add_uncached_list(rth);
2022 }
2023 }
2024 skb_dst_set(skb, &rth->dst);
2025 err = 0;
2026 goto out;
2027
2028 no_route:
2029 RT_CACHE_STAT_INC(in_no_route);
2030 res.type = RTN_UNREACHABLE;
2031 res.fi = NULL;
2032 res.table = NULL;
2033 goto local_input;
2034
2035 /*
2036 * Do not cache martian addresses: they should be logged (RFC1812)
2037 */
2038 martian_destination:
2039 RT_CACHE_STAT_INC(in_martian_dst);
2040 #ifdef CONFIG_IP_ROUTE_VERBOSE
2041 if (IN_DEV_LOG_MARTIANS(in_dev))
2042 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2043 &daddr, &saddr, dev->name);
2044 #endif
2045
2046 e_inval:
2047 err = -EINVAL;
2048 goto out;
2049
2050 e_nobufs:
2051 err = -ENOBUFS;
2052 goto out;
2053
2054 martian_source:
2055 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2056 goto out;
2057 }
2058
2059 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2060 u8 tos, struct net_device *dev)
2061 {
2062 int res;
2063
2064 tos &= IPTOS_RT_MASK;
2065 rcu_read_lock();
2066
2067 /* Multicast recognition logic is moved from route cache to here.
2068 The problem was that too many Ethernet cards have broken/missing
2069 hardware multicast filters :-( As result the host on multicasting
2070 network acquires a lot of useless route cache entries, sort of
2071 SDR messages from all the world. Now we try to get rid of them.
2072 Really, provided software IP multicast filter is organized
2073 reasonably (at least, hashed), it does not result in a slowdown
2074 comparing with route cache reject entries.
2075 Note, that multicast routers are not affected, because
2076 route cache entry is created eventually.
2077 */
2078 if (ipv4_is_multicast(daddr)) {
2079 struct in_device *in_dev = __in_dev_get_rcu(dev);
2080 int our = 0;
2081
2082 if (in_dev)
2083 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2084 ip_hdr(skb)->protocol);
2085
2086 /* check l3 master if no match yet */
2087 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2088 struct in_device *l3_in_dev;
2089
2090 l3_in_dev = __in_dev_get_rcu(skb->dev);
2091 if (l3_in_dev)
2092 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2093 ip_hdr(skb)->protocol);
2094 }
2095
2096 res = -EINVAL;
2097 if (our
2098 #ifdef CONFIG_IP_MROUTE
2099 ||
2100 (!ipv4_is_local_multicast(daddr) &&
2101 IN_DEV_MFORWARD(in_dev))
2102 #endif
2103 ) {
2104 res = ip_route_input_mc(skb, daddr, saddr,
2105 tos, dev, our);
2106 }
2107 rcu_read_unlock();
2108 return res;
2109 }
2110 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2111 rcu_read_unlock();
2112 return res;
2113 }
2114 EXPORT_SYMBOL(ip_route_input_noref);
2115
2116 /* called with rcu_read_lock() */
2117 static struct rtable *__mkroute_output(const struct fib_result *res,
2118 const struct flowi4 *fl4, int orig_oif,
2119 struct net_device *dev_out,
2120 unsigned int flags)
2121 {
2122 struct fib_info *fi = res->fi;
2123 struct fib_nh_exception *fnhe;
2124 struct in_device *in_dev;
2125 u16 type = res->type;
2126 struct rtable *rth;
2127 bool do_cache;
2128
2129 in_dev = __in_dev_get_rcu(dev_out);
2130 if (!in_dev)
2131 return ERR_PTR(-EINVAL);
2132
2133 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2134 if (ipv4_is_loopback(fl4->saddr) &&
2135 !(dev_out->flags & IFF_LOOPBACK) &&
2136 !netif_is_l3_master(dev_out))
2137 return ERR_PTR(-EINVAL);
2138
2139 if (ipv4_is_lbcast(fl4->daddr))
2140 type = RTN_BROADCAST;
2141 else if (ipv4_is_multicast(fl4->daddr))
2142 type = RTN_MULTICAST;
2143 else if (ipv4_is_zeronet(fl4->daddr))
2144 return ERR_PTR(-EINVAL);
2145
2146 if (dev_out->flags & IFF_LOOPBACK)
2147 flags |= RTCF_LOCAL;
2148
2149 do_cache = true;
2150 if (type == RTN_BROADCAST) {
2151 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2152 fi = NULL;
2153 } else if (type == RTN_MULTICAST) {
2154 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2155 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2156 fl4->flowi4_proto))
2157 flags &= ~RTCF_LOCAL;
2158 else
2159 do_cache = false;
2160 /* If multicast route do not exist use
2161 * default one, but do not gateway in this case.
2162 * Yes, it is hack.
2163 */
2164 if (fi && res->prefixlen < 4)
2165 fi = NULL;
2166 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2167 (orig_oif != dev_out->ifindex)) {
2168 /* For local routes that require a particular output interface
2169 * we do not want to cache the result. Caching the result
2170 * causes incorrect behaviour when there are multiple source
2171 * addresses on the interface, the end result being that if the
2172 * intended recipient is waiting on that interface for the
2173 * packet he won't receive it because it will be delivered on
2174 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2175 * be set to the loopback interface as well.
2176 */
2177 fi = NULL;
2178 }
2179
2180 fnhe = NULL;
2181 do_cache &= fi != NULL;
2182 if (do_cache) {
2183 struct rtable __rcu **prth;
2184 struct fib_nh *nh = &FIB_RES_NH(*res);
2185
2186 fnhe = find_exception(nh, fl4->daddr);
2187 if (fnhe) {
2188 prth = &fnhe->fnhe_rth_output;
2189 rth = rcu_dereference(*prth);
2190 if (rth && rth->dst.expires &&
2191 time_after(jiffies, rth->dst.expires)) {
2192 ip_del_fnhe(nh, fl4->daddr);
2193 fnhe = NULL;
2194 } else {
2195 goto rt_cache;
2196 }
2197 }
2198
2199 if (unlikely(fl4->flowi4_flags &
2200 FLOWI_FLAG_KNOWN_NH &&
2201 !(nh->nh_gw &&
2202 nh->nh_scope == RT_SCOPE_LINK))) {
2203 do_cache = false;
2204 goto add;
2205 }
2206 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2207 rth = rcu_dereference(*prth);
2208
2209 rt_cache:
2210 if (rt_cache_valid(rth)) {
2211 dst_hold(&rth->dst);
2212 return rth;
2213 }
2214 }
2215
2216 add:
2217 rth = rt_dst_alloc(dev_out, flags, type,
2218 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2219 IN_DEV_CONF_GET(in_dev, NOXFRM),
2220 do_cache);
2221 if (!rth)
2222 return ERR_PTR(-ENOBUFS);
2223
2224 rth->rt_iif = orig_oif ? : 0;
2225 if (res->table)
2226 rth->rt_table_id = res->table->tb_id;
2227
2228 RT_CACHE_STAT_INC(out_slow_tot);
2229
2230 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2231 if (flags & RTCF_LOCAL &&
2232 !(dev_out->flags & IFF_LOOPBACK)) {
2233 rth->dst.output = ip_mc_output;
2234 RT_CACHE_STAT_INC(out_slow_mc);
2235 }
2236 #ifdef CONFIG_IP_MROUTE
2237 if (type == RTN_MULTICAST) {
2238 if (IN_DEV_MFORWARD(in_dev) &&
2239 !ipv4_is_local_multicast(fl4->daddr)) {
2240 rth->dst.input = ip_mr_input;
2241 rth->dst.output = ip_mc_output;
2242 }
2243 }
2244 #endif
2245 }
2246
2247 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2248 set_lwt_redirect(rth);
2249
2250 return rth;
2251 }
2252
2253 /*
2254 * Major route resolver routine.
2255 */
2256
2257 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2258 const struct sk_buff *skb)
2259 {
2260 struct net_device *dev_out = NULL;
2261 __u8 tos = RT_FL_TOS(fl4);
2262 unsigned int flags = 0;
2263 struct fib_result res;
2264 struct rtable *rth;
2265 int orig_oif;
2266 int err = -ENETUNREACH;
2267
2268 res.tclassid = 0;
2269 res.fi = NULL;
2270 res.table = NULL;
2271
2272 orig_oif = fl4->flowi4_oif;
2273
2274 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2275 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2276 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2277 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2278
2279 rcu_read_lock();
2280 if (fl4->saddr) {
2281 rth = ERR_PTR(-EINVAL);
2282 if (ipv4_is_multicast(fl4->saddr) ||
2283 ipv4_is_lbcast(fl4->saddr) ||
2284 ipv4_is_zeronet(fl4->saddr))
2285 goto out;
2286
2287 /* I removed check for oif == dev_out->oif here.
2288 It was wrong for two reasons:
2289 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2290 is assigned to multiple interfaces.
2291 2. Moreover, we are allowed to send packets with saddr
2292 of another iface. --ANK
2293 */
2294
2295 if (fl4->flowi4_oif == 0 &&
2296 (ipv4_is_multicast(fl4->daddr) ||
2297 ipv4_is_lbcast(fl4->daddr))) {
2298 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2299 dev_out = __ip_dev_find(net, fl4->saddr, false);
2300 if (!dev_out)
2301 goto out;
2302
2303 /* Special hack: user can direct multicasts
2304 and limited broadcast via necessary interface
2305 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2306 This hack is not just for fun, it allows
2307 vic,vat and friends to work.
2308 They bind socket to loopback, set ttl to zero
2309 and expect that it will work.
2310 From the viewpoint of routing cache they are broken,
2311 because we are not allowed to build multicast path
2312 with loopback source addr (look, routing cache
2313 cannot know, that ttl is zero, so that packet
2314 will not leave this host and route is valid).
2315 Luckily, this hack is good workaround.
2316 */
2317
2318 fl4->flowi4_oif = dev_out->ifindex;
2319 goto make_route;
2320 }
2321
2322 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2323 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2324 if (!__ip_dev_find(net, fl4->saddr, false))
2325 goto out;
2326 }
2327 }
2328
2329
2330 if (fl4->flowi4_oif) {
2331 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2332 rth = ERR_PTR(-ENODEV);
2333 if (!dev_out)
2334 goto out;
2335
2336 /* RACE: Check return value of inet_select_addr instead. */
2337 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2338 rth = ERR_PTR(-ENETUNREACH);
2339 goto out;
2340 }
2341 if (ipv4_is_local_multicast(fl4->daddr) ||
2342 ipv4_is_lbcast(fl4->daddr) ||
2343 fl4->flowi4_proto == IPPROTO_IGMP) {
2344 if (!fl4->saddr)
2345 fl4->saddr = inet_select_addr(dev_out, 0,
2346 RT_SCOPE_LINK);
2347 goto make_route;
2348 }
2349 if (!fl4->saddr) {
2350 if (ipv4_is_multicast(fl4->daddr))
2351 fl4->saddr = inet_select_addr(dev_out, 0,
2352 fl4->flowi4_scope);
2353 else if (!fl4->daddr)
2354 fl4->saddr = inet_select_addr(dev_out, 0,
2355 RT_SCOPE_HOST);
2356 }
2357 }
2358
2359 if (!fl4->daddr) {
2360 fl4->daddr = fl4->saddr;
2361 if (!fl4->daddr)
2362 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2363 dev_out = net->loopback_dev;
2364 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2365 res.type = RTN_LOCAL;
2366 flags |= RTCF_LOCAL;
2367 goto make_route;
2368 }
2369
2370 err = fib_lookup(net, fl4, &res, 0);
2371 if (err) {
2372 res.fi = NULL;
2373 res.table = NULL;
2374 if (fl4->flowi4_oif &&
2375 (ipv4_is_multicast(fl4->daddr) ||
2376 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2377 /* Apparently, routing tables are wrong. Assume,
2378 that the destination is on link.
2379
2380 WHY? DW.
2381 Because we are allowed to send to iface
2382 even if it has NO routes and NO assigned
2383 addresses. When oif is specified, routing
2384 tables are looked up with only one purpose:
2385 to catch if destination is gatewayed, rather than
2386 direct. Moreover, if MSG_DONTROUTE is set,
2387 we send packet, ignoring both routing tables
2388 and ifaddr state. --ANK
2389
2390
2391 We could make it even if oif is unknown,
2392 likely IPv6, but we do not.
2393 */
2394
2395 if (fl4->saddr == 0)
2396 fl4->saddr = inet_select_addr(dev_out, 0,
2397 RT_SCOPE_LINK);
2398 res.type = RTN_UNICAST;
2399 goto make_route;
2400 }
2401 rth = ERR_PTR(err);
2402 goto out;
2403 }
2404
2405 if (res.type == RTN_LOCAL) {
2406 if (!fl4->saddr) {
2407 if (res.fi->fib_prefsrc)
2408 fl4->saddr = res.fi->fib_prefsrc;
2409 else
2410 fl4->saddr = fl4->daddr;
2411 }
2412
2413 /* L3 master device is the loopback for that domain */
2414 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(res)) ? :
2415 net->loopback_dev;
2416 fl4->flowi4_oif = dev_out->ifindex;
2417 flags |= RTCF_LOCAL;
2418 goto make_route;
2419 }
2420
2421 fib_select_path(net, &res, fl4, skb);
2422
2423 dev_out = FIB_RES_DEV(res);
2424 fl4->flowi4_oif = dev_out->ifindex;
2425
2426
2427 make_route:
2428 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2429
2430 out:
2431 rcu_read_unlock();
2432 return rth;
2433 }
2434 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2435
2436 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2437 {
2438 return NULL;
2439 }
2440
2441 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2442 {
2443 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2444
2445 return mtu ? : dst->dev->mtu;
2446 }
2447
2448 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2449 struct sk_buff *skb, u32 mtu)
2450 {
2451 }
2452
2453 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2454 struct sk_buff *skb)
2455 {
2456 }
2457
2458 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2459 unsigned long old)
2460 {
2461 return NULL;
2462 }
2463
2464 static struct dst_ops ipv4_dst_blackhole_ops = {
2465 .family = AF_INET,
2466 .check = ipv4_blackhole_dst_check,
2467 .mtu = ipv4_blackhole_mtu,
2468 .default_advmss = ipv4_default_advmss,
2469 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2470 .redirect = ipv4_rt_blackhole_redirect,
2471 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2472 .neigh_lookup = ipv4_neigh_lookup,
2473 };
2474
2475 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2476 {
2477 struct rtable *ort = (struct rtable *) dst_orig;
2478 struct rtable *rt;
2479
2480 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2481 if (rt) {
2482 struct dst_entry *new = &rt->dst;
2483
2484 new->__use = 1;
2485 new->input = dst_discard;
2486 new->output = dst_discard_out;
2487
2488 new->dev = ort->dst.dev;
2489 if (new->dev)
2490 dev_hold(new->dev);
2491
2492 rt->rt_is_input = ort->rt_is_input;
2493 rt->rt_iif = ort->rt_iif;
2494 rt->rt_pmtu = ort->rt_pmtu;
2495
2496 rt->rt_genid = rt_genid_ipv4(net);
2497 rt->rt_flags = ort->rt_flags;
2498 rt->rt_type = ort->rt_type;
2499 rt->rt_gateway = ort->rt_gateway;
2500 rt->rt_uses_gateway = ort->rt_uses_gateway;
2501
2502 INIT_LIST_HEAD(&rt->rt_uncached);
2503 dst_free(new);
2504 }
2505
2506 dst_release(dst_orig);
2507
2508 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2509 }
2510
2511 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2512 const struct sock *sk)
2513 {
2514 struct rtable *rt = __ip_route_output_key(net, flp4);
2515
2516 if (IS_ERR(rt))
2517 return rt;
2518
2519 if (flp4->flowi4_proto)
2520 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2521 flowi4_to_flowi(flp4),
2522 sk, 0);
2523
2524 return rt;
2525 }
2526 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2527
2528 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2529 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2530 u32 seq, int event)
2531 {
2532 struct rtable *rt = skb_rtable(skb);
2533 struct rtmsg *r;
2534 struct nlmsghdr *nlh;
2535 unsigned long expires = 0;
2536 u32 error;
2537 u32 metrics[RTAX_MAX];
2538
2539 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), 0);
2540 if (!nlh)
2541 return -EMSGSIZE;
2542
2543 r = nlmsg_data(nlh);
2544 r->rtm_family = AF_INET;
2545 r->rtm_dst_len = 32;
2546 r->rtm_src_len = 0;
2547 r->rtm_tos = fl4->flowi4_tos;
2548 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2549 if (nla_put_u32(skb, RTA_TABLE, table_id))
2550 goto nla_put_failure;
2551 r->rtm_type = rt->rt_type;
2552 r->rtm_scope = RT_SCOPE_UNIVERSE;
2553 r->rtm_protocol = RTPROT_UNSPEC;
2554 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2555 if (rt->rt_flags & RTCF_NOTIFY)
2556 r->rtm_flags |= RTM_F_NOTIFY;
2557 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2558 r->rtm_flags |= RTCF_DOREDIRECT;
2559
2560 if (nla_put_in_addr(skb, RTA_DST, dst))
2561 goto nla_put_failure;
2562 if (src) {
2563 r->rtm_src_len = 32;
2564 if (nla_put_in_addr(skb, RTA_SRC, src))
2565 goto nla_put_failure;
2566 }
2567 if (rt->dst.dev &&
2568 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2569 goto nla_put_failure;
2570 #ifdef CONFIG_IP_ROUTE_CLASSID
2571 if (rt->dst.tclassid &&
2572 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2573 goto nla_put_failure;
2574 #endif
2575 if (!rt_is_input_route(rt) &&
2576 fl4->saddr != src) {
2577 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2578 goto nla_put_failure;
2579 }
2580 if (rt->rt_uses_gateway &&
2581 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2582 goto nla_put_failure;
2583
2584 expires = rt->dst.expires;
2585 if (expires) {
2586 unsigned long now = jiffies;
2587
2588 if (time_before(now, expires))
2589 expires -= now;
2590 else
2591 expires = 0;
2592 }
2593
2594 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2595 if (rt->rt_pmtu && expires)
2596 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2597 if (rtnetlink_put_metrics(skb, metrics) < 0)
2598 goto nla_put_failure;
2599
2600 if (fl4->flowi4_mark &&
2601 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2602 goto nla_put_failure;
2603
2604 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2605 nla_put_u32(skb, RTA_UID,
2606 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2607 goto nla_put_failure;
2608
2609 error = rt->dst.error;
2610
2611 if (rt_is_input_route(rt)) {
2612 #ifdef CONFIG_IP_MROUTE
2613 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2614 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2615 int err = ipmr_get_route(net, skb,
2616 fl4->saddr, fl4->daddr,
2617 r, portid);
2618
2619 if (err <= 0) {
2620 if (err == 0)
2621 return 0;
2622 goto nla_put_failure;
2623 }
2624 } else
2625 #endif
2626 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2627 goto nla_put_failure;
2628 }
2629
2630 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2631 goto nla_put_failure;
2632
2633 nlmsg_end(skb, nlh);
2634 return 0;
2635
2636 nla_put_failure:
2637 nlmsg_cancel(skb, nlh);
2638 return -EMSGSIZE;
2639 }
2640
2641 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2642 struct netlink_ext_ack *extack)
2643 {
2644 struct net *net = sock_net(in_skb->sk);
2645 struct rtmsg *rtm;
2646 struct nlattr *tb[RTA_MAX+1];
2647 struct rtable *rt = NULL;
2648 struct flowi4 fl4;
2649 __be32 dst = 0;
2650 __be32 src = 0;
2651 u32 iif;
2652 int err;
2653 int mark;
2654 struct sk_buff *skb;
2655 u32 table_id = RT_TABLE_MAIN;
2656 kuid_t uid;
2657
2658 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2659 extack);
2660 if (err < 0)
2661 goto errout;
2662
2663 rtm = nlmsg_data(nlh);
2664
2665 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2666 if (!skb) {
2667 err = -ENOBUFS;
2668 goto errout;
2669 }
2670
2671 /* Reserve room for dummy headers, this skb can pass
2672 through good chunk of routing engine.
2673 */
2674 skb_reset_mac_header(skb);
2675 skb_reset_network_header(skb);
2676
2677 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2678 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2679 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2680 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2681 if (tb[RTA_UID])
2682 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2683 else
2684 uid = (iif ? INVALID_UID : current_uid());
2685
2686 /* Bugfix: need to give ip_route_input enough of an IP header to
2687 * not gag.
2688 */
2689 ip_hdr(skb)->protocol = IPPROTO_UDP;
2690 ip_hdr(skb)->saddr = src;
2691 ip_hdr(skb)->daddr = dst;
2692
2693 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2694
2695 memset(&fl4, 0, sizeof(fl4));
2696 fl4.daddr = dst;
2697 fl4.saddr = src;
2698 fl4.flowi4_tos = rtm->rtm_tos;
2699 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2700 fl4.flowi4_mark = mark;
2701 fl4.flowi4_uid = uid;
2702
2703 if (iif) {
2704 struct net_device *dev;
2705
2706 dev = __dev_get_by_index(net, iif);
2707 if (!dev) {
2708 err = -ENODEV;
2709 goto errout_free;
2710 }
2711
2712 skb->protocol = htons(ETH_P_IP);
2713 skb->dev = dev;
2714 skb->mark = mark;
2715 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2716
2717 rt = skb_rtable(skb);
2718 if (err == 0 && rt->dst.error)
2719 err = -rt->dst.error;
2720 } else {
2721 rt = ip_route_output_key(net, &fl4);
2722
2723 err = 0;
2724 if (IS_ERR(rt))
2725 err = PTR_ERR(rt);
2726 }
2727
2728 if (err)
2729 goto errout_free;
2730
2731 skb_dst_set(skb, &rt->dst);
2732 if (rtm->rtm_flags & RTM_F_NOTIFY)
2733 rt->rt_flags |= RTCF_NOTIFY;
2734
2735 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2736 table_id = rt->rt_table_id;
2737
2738 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2739 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2740 RTM_NEWROUTE);
2741 if (err < 0)
2742 goto errout_free;
2743
2744 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2745 errout:
2746 return err;
2747
2748 errout_free:
2749 kfree_skb(skb);
2750 goto errout;
2751 }
2752
2753 void ip_rt_multicast_event(struct in_device *in_dev)
2754 {
2755 rt_cache_flush(dev_net(in_dev->dev));
2756 }
2757
2758 #ifdef CONFIG_SYSCTL
2759 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2760 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2761 static int ip_rt_gc_elasticity __read_mostly = 8;
2762
2763 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2764 void __user *buffer,
2765 size_t *lenp, loff_t *ppos)
2766 {
2767 struct net *net = (struct net *)__ctl->extra1;
2768
2769 if (write) {
2770 rt_cache_flush(net);
2771 fnhe_genid_bump(net);
2772 return 0;
2773 }
2774
2775 return -EINVAL;
2776 }
2777
2778 static struct ctl_table ipv4_route_table[] = {
2779 {
2780 .procname = "gc_thresh",
2781 .data = &ipv4_dst_ops.gc_thresh,
2782 .maxlen = sizeof(int),
2783 .mode = 0644,
2784 .proc_handler = proc_dointvec,
2785 },
2786 {
2787 .procname = "max_size",
2788 .data = &ip_rt_max_size,
2789 .maxlen = sizeof(int),
2790 .mode = 0644,
2791 .proc_handler = proc_dointvec,
2792 },
2793 {
2794 /* Deprecated. Use gc_min_interval_ms */
2795
2796 .procname = "gc_min_interval",
2797 .data = &ip_rt_gc_min_interval,
2798 .maxlen = sizeof(int),
2799 .mode = 0644,
2800 .proc_handler = proc_dointvec_jiffies,
2801 },
2802 {
2803 .procname = "gc_min_interval_ms",
2804 .data = &ip_rt_gc_min_interval,
2805 .maxlen = sizeof(int),
2806 .mode = 0644,
2807 .proc_handler = proc_dointvec_ms_jiffies,
2808 },
2809 {
2810 .procname = "gc_timeout",
2811 .data = &ip_rt_gc_timeout,
2812 .maxlen = sizeof(int),
2813 .mode = 0644,
2814 .proc_handler = proc_dointvec_jiffies,
2815 },
2816 {
2817 .procname = "gc_interval",
2818 .data = &ip_rt_gc_interval,
2819 .maxlen = sizeof(int),
2820 .mode = 0644,
2821 .proc_handler = proc_dointvec_jiffies,
2822 },
2823 {
2824 .procname = "redirect_load",
2825 .data = &ip_rt_redirect_load,
2826 .maxlen = sizeof(int),
2827 .mode = 0644,
2828 .proc_handler = proc_dointvec,
2829 },
2830 {
2831 .procname = "redirect_number",
2832 .data = &ip_rt_redirect_number,
2833 .maxlen = sizeof(int),
2834 .mode = 0644,
2835 .proc_handler = proc_dointvec,
2836 },
2837 {
2838 .procname = "redirect_silence",
2839 .data = &ip_rt_redirect_silence,
2840 .maxlen = sizeof(int),
2841 .mode = 0644,
2842 .proc_handler = proc_dointvec,
2843 },
2844 {
2845 .procname = "error_cost",
2846 .data = &ip_rt_error_cost,
2847 .maxlen = sizeof(int),
2848 .mode = 0644,
2849 .proc_handler = proc_dointvec,
2850 },
2851 {
2852 .procname = "error_burst",
2853 .data = &ip_rt_error_burst,
2854 .maxlen = sizeof(int),
2855 .mode = 0644,
2856 .proc_handler = proc_dointvec,
2857 },
2858 {
2859 .procname = "gc_elasticity",
2860 .data = &ip_rt_gc_elasticity,
2861 .maxlen = sizeof(int),
2862 .mode = 0644,
2863 .proc_handler = proc_dointvec,
2864 },
2865 {
2866 .procname = "mtu_expires",
2867 .data = &ip_rt_mtu_expires,
2868 .maxlen = sizeof(int),
2869 .mode = 0644,
2870 .proc_handler = proc_dointvec_jiffies,
2871 },
2872 {
2873 .procname = "min_pmtu",
2874 .data = &ip_rt_min_pmtu,
2875 .maxlen = sizeof(int),
2876 .mode = 0644,
2877 .proc_handler = proc_dointvec,
2878 },
2879 {
2880 .procname = "min_adv_mss",
2881 .data = &ip_rt_min_advmss,
2882 .maxlen = sizeof(int),
2883 .mode = 0644,
2884 .proc_handler = proc_dointvec,
2885 },
2886 { }
2887 };
2888
2889 static struct ctl_table ipv4_route_flush_table[] = {
2890 {
2891 .procname = "flush",
2892 .maxlen = sizeof(int),
2893 .mode = 0200,
2894 .proc_handler = ipv4_sysctl_rtcache_flush,
2895 },
2896 { },
2897 };
2898
2899 static __net_init int sysctl_route_net_init(struct net *net)
2900 {
2901 struct ctl_table *tbl;
2902
2903 tbl = ipv4_route_flush_table;
2904 if (!net_eq(net, &init_net)) {
2905 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2906 if (!tbl)
2907 goto err_dup;
2908
2909 /* Don't export sysctls to unprivileged users */
2910 if (net->user_ns != &init_user_ns)
2911 tbl[0].procname = NULL;
2912 }
2913 tbl[0].extra1 = net;
2914
2915 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2916 if (!net->ipv4.route_hdr)
2917 goto err_reg;
2918 return 0;
2919
2920 err_reg:
2921 if (tbl != ipv4_route_flush_table)
2922 kfree(tbl);
2923 err_dup:
2924 return -ENOMEM;
2925 }
2926
2927 static __net_exit void sysctl_route_net_exit(struct net *net)
2928 {
2929 struct ctl_table *tbl;
2930
2931 tbl = net->ipv4.route_hdr->ctl_table_arg;
2932 unregister_net_sysctl_table(net->ipv4.route_hdr);
2933 BUG_ON(tbl == ipv4_route_flush_table);
2934 kfree(tbl);
2935 }
2936
2937 static __net_initdata struct pernet_operations sysctl_route_ops = {
2938 .init = sysctl_route_net_init,
2939 .exit = sysctl_route_net_exit,
2940 };
2941 #endif
2942
2943 static __net_init int rt_genid_init(struct net *net)
2944 {
2945 atomic_set(&net->ipv4.rt_genid, 0);
2946 atomic_set(&net->fnhe_genid, 0);
2947 get_random_bytes(&net->ipv4.dev_addr_genid,
2948 sizeof(net->ipv4.dev_addr_genid));
2949 return 0;
2950 }
2951
2952 static __net_initdata struct pernet_operations rt_genid_ops = {
2953 .init = rt_genid_init,
2954 };
2955
2956 static int __net_init ipv4_inetpeer_init(struct net *net)
2957 {
2958 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2959
2960 if (!bp)
2961 return -ENOMEM;
2962 inet_peer_base_init(bp);
2963 net->ipv4.peers = bp;
2964 return 0;
2965 }
2966
2967 static void __net_exit ipv4_inetpeer_exit(struct net *net)
2968 {
2969 struct inet_peer_base *bp = net->ipv4.peers;
2970
2971 net->ipv4.peers = NULL;
2972 inetpeer_invalidate_tree(bp);
2973 kfree(bp);
2974 }
2975
2976 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2977 .init = ipv4_inetpeer_init,
2978 .exit = ipv4_inetpeer_exit,
2979 };
2980
2981 #ifdef CONFIG_IP_ROUTE_CLASSID
2982 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2983 #endif /* CONFIG_IP_ROUTE_CLASSID */
2984
2985 int __init ip_rt_init(void)
2986 {
2987 int rc = 0;
2988 int cpu;
2989
2990 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2991 if (!ip_idents)
2992 panic("IP: failed to allocate ip_idents\n");
2993
2994 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2995
2996 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2997 if (!ip_tstamps)
2998 panic("IP: failed to allocate ip_tstamps\n");
2999
3000 for_each_possible_cpu(cpu) {
3001 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3002
3003 INIT_LIST_HEAD(&ul->head);
3004 spin_lock_init(&ul->lock);
3005 }
3006 #ifdef CONFIG_IP_ROUTE_CLASSID
3007 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3008 if (!ip_rt_acct)
3009 panic("IP: failed to allocate ip_rt_acct\n");
3010 #endif
3011
3012 ipv4_dst_ops.kmem_cachep =
3013 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3014 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3015
3016 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3017
3018 if (dst_entries_init(&ipv4_dst_ops) < 0)
3019 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3020
3021 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3022 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3023
3024 ipv4_dst_ops.gc_thresh = ~0;
3025 ip_rt_max_size = INT_MAX;
3026
3027 devinet_init();
3028 ip_fib_init();
3029
3030 if (ip_rt_proc_init())
3031 pr_err("Unable to create route proc files\n");
3032 #ifdef CONFIG_XFRM
3033 xfrm_init();
3034 xfrm4_init();
3035 #endif
3036 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3037
3038 #ifdef CONFIG_SYSCTL
3039 register_pernet_subsys(&sysctl_route_ops);
3040 #endif
3041 register_pernet_subsys(&rt_genid_ops);
3042 register_pernet_subsys(&ipv4_inetpeer_ops);
3043 return rc;
3044 }
3045
3046 #ifdef CONFIG_SYSCTL
3047 /*
3048 * We really need to sanitize the damn ipv4 init order, then all
3049 * this nonsense will go away.
3050 */
3051 void __init ip_static_sysctl_init(void)
3052 {
3053 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3054 }
3055 #endif
Ubuntu Artful kernel mirror