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[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 #include "fib_lookup.h"
118
119 #define RT_FL_TOS(oldflp4) \
120 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
121
122 #define RT_GC_TIMEOUT (300*HZ)
123
124 static int ip_rt_max_size;
125 static int ip_rt_redirect_number __read_mostly = 9;
126 static int ip_rt_redirect_load __read_mostly = HZ / 50;
127 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
128 static int ip_rt_error_cost __read_mostly = HZ;
129 static int ip_rt_error_burst __read_mostly = 5 * HZ;
130 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
131 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
132 static int ip_rt_min_advmss __read_mostly = 256;
133
134 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
135 /*
136 * Interface to generic destination cache.
137 */
138
139 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
140 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
141 static unsigned int ipv4_mtu(const struct dst_entry *dst);
142 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
143 static void ipv4_link_failure(struct sk_buff *skb);
144 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb, u32 mtu);
146 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
147 struct sk_buff *skb);
148 static void ipv4_dst_destroy(struct dst_entry *dst);
149
150 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
151 {
152 WARN_ON(1);
153 return NULL;
154 }
155
156 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
157 struct sk_buff *skb,
158 const void *daddr);
159 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
160
161 static struct dst_ops ipv4_dst_ops = {
162 .family = AF_INET,
163 .check = ipv4_dst_check,
164 .default_advmss = ipv4_default_advmss,
165 .mtu = ipv4_mtu,
166 .cow_metrics = ipv4_cow_metrics,
167 .destroy = ipv4_dst_destroy,
168 .negative_advice = ipv4_negative_advice,
169 .link_failure = ipv4_link_failure,
170 .update_pmtu = ip_rt_update_pmtu,
171 .redirect = ip_do_redirect,
172 .local_out = __ip_local_out,
173 .neigh_lookup = ipv4_neigh_lookup,
174 .confirm_neigh = ipv4_confirm_neigh,
175 };
176
177 #define ECN_OR_COST(class) TC_PRIO_##class
178
179 const __u8 ip_tos2prio[16] = {
180 TC_PRIO_BESTEFFORT,
181 ECN_OR_COST(BESTEFFORT),
182 TC_PRIO_BESTEFFORT,
183 ECN_OR_COST(BESTEFFORT),
184 TC_PRIO_BULK,
185 ECN_OR_COST(BULK),
186 TC_PRIO_BULK,
187 ECN_OR_COST(BULK),
188 TC_PRIO_INTERACTIVE,
189 ECN_OR_COST(INTERACTIVE),
190 TC_PRIO_INTERACTIVE,
191 ECN_OR_COST(INTERACTIVE),
192 TC_PRIO_INTERACTIVE_BULK,
193 ECN_OR_COST(INTERACTIVE_BULK),
194 TC_PRIO_INTERACTIVE_BULK,
195 ECN_OR_COST(INTERACTIVE_BULK)
196 };
197 EXPORT_SYMBOL(ip_tos2prio);
198
199 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
200 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
201
202 #ifdef CONFIG_PROC_FS
203 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
204 {
205 if (*pos)
206 return NULL;
207 return SEQ_START_TOKEN;
208 }
209
210 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
211 {
212 ++*pos;
213 return NULL;
214 }
215
216 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
217 {
218 }
219
220 static int rt_cache_seq_show(struct seq_file *seq, void *v)
221 {
222 if (v == SEQ_START_TOKEN)
223 seq_printf(seq, "%-127s\n",
224 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
225 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
226 "HHUptod\tSpecDst");
227 return 0;
228 }
229
230 static const struct seq_operations rt_cache_seq_ops = {
231 .start = rt_cache_seq_start,
232 .next = rt_cache_seq_next,
233 .stop = rt_cache_seq_stop,
234 .show = rt_cache_seq_show,
235 };
236
237 static int rt_cache_seq_open(struct inode *inode, struct file *file)
238 {
239 return seq_open(file, &rt_cache_seq_ops);
240 }
241
242 static const struct file_operations rt_cache_seq_fops = {
243 .owner = THIS_MODULE,
244 .open = rt_cache_seq_open,
245 .read = seq_read,
246 .llseek = seq_lseek,
247 .release = seq_release,
248 };
249
250
251 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
252 {
253 int cpu;
254
255 if (*pos == 0)
256 return SEQ_START_TOKEN;
257
258 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
259 if (!cpu_possible(cpu))
260 continue;
261 *pos = cpu+1;
262 return &per_cpu(rt_cache_stat, cpu);
263 }
264 return NULL;
265 }
266
267 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
268 {
269 int cpu;
270
271 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
272 if (!cpu_possible(cpu))
273 continue;
274 *pos = cpu+1;
275 return &per_cpu(rt_cache_stat, cpu);
276 }
277 return NULL;
278
279 }
280
281 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
282 {
283
284 }
285
286 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
287 {
288 struct rt_cache_stat *st = v;
289
290 if (v == SEQ_START_TOKEN) {
291 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");
292 return 0;
293 }
294
295 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
296 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
297 dst_entries_get_slow(&ipv4_dst_ops),
298 0, /* st->in_hit */
299 st->in_slow_tot,
300 st->in_slow_mc,
301 st->in_no_route,
302 st->in_brd,
303 st->in_martian_dst,
304 st->in_martian_src,
305
306 0, /* st->out_hit */
307 st->out_slow_tot,
308 st->out_slow_mc,
309
310 0, /* st->gc_total */
311 0, /* st->gc_ignored */
312 0, /* st->gc_goal_miss */
313 0, /* st->gc_dst_overflow */
314 0, /* st->in_hlist_search */
315 0 /* st->out_hlist_search */
316 );
317 return 0;
318 }
319
320 static const struct seq_operations rt_cpu_seq_ops = {
321 .start = rt_cpu_seq_start,
322 .next = rt_cpu_seq_next,
323 .stop = rt_cpu_seq_stop,
324 .show = rt_cpu_seq_show,
325 };
326
327
328 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
329 {
330 return seq_open(file, &rt_cpu_seq_ops);
331 }
332
333 static const struct file_operations rt_cpu_seq_fops = {
334 .owner = THIS_MODULE,
335 .open = rt_cpu_seq_open,
336 .read = seq_read,
337 .llseek = seq_lseek,
338 .release = seq_release,
339 };
340
341 #ifdef CONFIG_IP_ROUTE_CLASSID
342 static int rt_acct_proc_show(struct seq_file *m, void *v)
343 {
344 struct ip_rt_acct *dst, *src;
345 unsigned int i, j;
346
347 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
348 if (!dst)
349 return -ENOMEM;
350
351 for_each_possible_cpu(i) {
352 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
353 for (j = 0; j < 256; j++) {
354 dst[j].o_bytes += src[j].o_bytes;
355 dst[j].o_packets += src[j].o_packets;
356 dst[j].i_bytes += src[j].i_bytes;
357 dst[j].i_packets += src[j].i_packets;
358 }
359 }
360
361 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
362 kfree(dst);
363 return 0;
364 }
365
366 static int rt_acct_proc_open(struct inode *inode, struct file *file)
367 {
368 return single_open(file, rt_acct_proc_show, NULL);
369 }
370
371 static const struct file_operations rt_acct_proc_fops = {
372 .owner = THIS_MODULE,
373 .open = rt_acct_proc_open,
374 .read = seq_read,
375 .llseek = seq_lseek,
376 .release = single_release,
377 };
378 #endif
379
380 static int __net_init ip_rt_do_proc_init(struct net *net)
381 {
382 struct proc_dir_entry *pde;
383
384 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
385 &rt_cache_seq_fops);
386 if (!pde)
387 goto err1;
388
389 pde = proc_create("rt_cache", S_IRUGO,
390 net->proc_net_stat, &rt_cpu_seq_fops);
391 if (!pde)
392 goto err2;
393
394 #ifdef CONFIG_IP_ROUTE_CLASSID
395 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
396 if (!pde)
397 goto err3;
398 #endif
399 return 0;
400
401 #ifdef CONFIG_IP_ROUTE_CLASSID
402 err3:
403 remove_proc_entry("rt_cache", net->proc_net_stat);
404 #endif
405 err2:
406 remove_proc_entry("rt_cache", net->proc_net);
407 err1:
408 return -ENOMEM;
409 }
410
411 static void __net_exit ip_rt_do_proc_exit(struct net *net)
412 {
413 remove_proc_entry("rt_cache", net->proc_net_stat);
414 remove_proc_entry("rt_cache", net->proc_net);
415 #ifdef CONFIG_IP_ROUTE_CLASSID
416 remove_proc_entry("rt_acct", net->proc_net);
417 #endif
418 }
419
420 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
421 .init = ip_rt_do_proc_init,
422 .exit = ip_rt_do_proc_exit,
423 };
424
425 static int __init ip_rt_proc_init(void)
426 {
427 return register_pernet_subsys(&ip_rt_proc_ops);
428 }
429
430 #else
431 static inline int ip_rt_proc_init(void)
432 {
433 return 0;
434 }
435 #endif /* CONFIG_PROC_FS */
436
437 static inline bool rt_is_expired(const struct rtable *rth)
438 {
439 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
440 }
441
442 void rt_cache_flush(struct net *net)
443 {
444 rt_genid_bump_ipv4(net);
445 }
446
447 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
448 struct sk_buff *skb,
449 const void *daddr)
450 {
451 struct net_device *dev = dst->dev;
452 const __be32 *pkey = daddr;
453 const struct rtable *rt;
454 struct neighbour *n;
455
456 rt = (const struct rtable *) dst;
457 if (rt->rt_gateway)
458 pkey = (const __be32 *) &rt->rt_gateway;
459 else if (skb)
460 pkey = &ip_hdr(skb)->daddr;
461
462 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
463 if (n)
464 return n;
465 return neigh_create(&arp_tbl, pkey, dev);
466 }
467
468 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
469 {
470 struct net_device *dev = dst->dev;
471 const __be32 *pkey = daddr;
472 const struct rtable *rt;
473
474 rt = (const struct rtable *)dst;
475 if (rt->rt_gateway)
476 pkey = (const __be32 *)&rt->rt_gateway;
477 else if (!daddr ||
478 (rt->rt_flags &
479 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
480 return;
481
482 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
483 }
484
485 #define IP_IDENTS_SZ 2048u
486
487 static atomic_t *ip_idents __read_mostly;
488 static u32 *ip_tstamps __read_mostly;
489
490 /* In order to protect privacy, we add a perturbation to identifiers
491 * if one generator is seldom used. This makes hard for an attacker
492 * to infer how many packets were sent between two points in time.
493 */
494 u32 ip_idents_reserve(u32 hash, int segs)
495 {
496 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
497 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
498 u32 old = ACCESS_ONCE(*p_tstamp);
499 u32 now = (u32)jiffies;
500 u32 new, delta = 0;
501
502 if (old != now && cmpxchg(p_tstamp, old, now) == old)
503 delta = prandom_u32_max(now - old);
504
505 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
506 do {
507 old = (u32)atomic_read(p_id);
508 new = old + delta + segs;
509 } while (atomic_cmpxchg(p_id, old, new) != old);
510
511 return new - segs;
512 }
513 EXPORT_SYMBOL(ip_idents_reserve);
514
515 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
516 {
517 static u32 ip_idents_hashrnd __read_mostly;
518 u32 hash, id;
519
520 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
521
522 hash = jhash_3words((__force u32)iph->daddr,
523 (__force u32)iph->saddr,
524 iph->protocol ^ net_hash_mix(net),
525 ip_idents_hashrnd);
526 id = ip_idents_reserve(hash, segs);
527 iph->id = htons(id);
528 }
529 EXPORT_SYMBOL(__ip_select_ident);
530
531 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
532 const struct sock *sk,
533 const struct iphdr *iph,
534 int oif, u8 tos,
535 u8 prot, u32 mark, int flow_flags)
536 {
537 if (sk) {
538 const struct inet_sock *inet = inet_sk(sk);
539
540 oif = sk->sk_bound_dev_if;
541 mark = sk->sk_mark;
542 tos = RT_CONN_FLAGS(sk);
543 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
544 }
545 flowi4_init_output(fl4, oif, mark, tos,
546 RT_SCOPE_UNIVERSE, prot,
547 flow_flags,
548 iph->daddr, iph->saddr, 0, 0,
549 sock_net_uid(net, sk));
550 }
551
552 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
553 const struct sock *sk)
554 {
555 const struct net *net = dev_net(skb->dev);
556 const struct iphdr *iph = ip_hdr(skb);
557 int oif = skb->dev->ifindex;
558 u8 tos = RT_TOS(iph->tos);
559 u8 prot = iph->protocol;
560 u32 mark = skb->mark;
561
562 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
563 }
564
565 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
566 {
567 const struct inet_sock *inet = inet_sk(sk);
568 const struct ip_options_rcu *inet_opt;
569 __be32 daddr = inet->inet_daddr;
570
571 rcu_read_lock();
572 inet_opt = rcu_dereference(inet->inet_opt);
573 if (inet_opt && inet_opt->opt.srr)
574 daddr = inet_opt->opt.faddr;
575 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
576 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
577 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
578 inet_sk_flowi_flags(sk),
579 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
580 rcu_read_unlock();
581 }
582
583 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
584 const struct sk_buff *skb)
585 {
586 if (skb)
587 build_skb_flow_key(fl4, skb, sk);
588 else
589 build_sk_flow_key(fl4, sk);
590 }
591
592 static DEFINE_SPINLOCK(fnhe_lock);
593
594 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
595 {
596 struct rtable *rt;
597
598 rt = rcu_dereference(fnhe->fnhe_rth_input);
599 if (rt) {
600 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
601 dst_dev_put(&rt->dst);
602 dst_release(&rt->dst);
603 }
604 rt = rcu_dereference(fnhe->fnhe_rth_output);
605 if (rt) {
606 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
607 dst_dev_put(&rt->dst);
608 dst_release(&rt->dst);
609 }
610 }
611
612 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
613 {
614 struct fib_nh_exception *fnhe, *oldest;
615
616 oldest = rcu_dereference(hash->chain);
617 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
618 fnhe = rcu_dereference(fnhe->fnhe_next)) {
619 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
620 oldest = fnhe;
621 }
622 fnhe_flush_routes(oldest);
623 return oldest;
624 }
625
626 static inline u32 fnhe_hashfun(__be32 daddr)
627 {
628 static u32 fnhe_hashrnd __read_mostly;
629 u32 hval;
630
631 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
632 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
633 return hash_32(hval, FNHE_HASH_SHIFT);
634 }
635
636 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
637 {
638 rt->rt_pmtu = fnhe->fnhe_pmtu;
639 rt->dst.expires = fnhe->fnhe_expires;
640
641 if (fnhe->fnhe_gw) {
642 rt->rt_flags |= RTCF_REDIRECTED;
643 rt->rt_gateway = fnhe->fnhe_gw;
644 rt->rt_uses_gateway = 1;
645 }
646 }
647
648 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
649 u32 pmtu, unsigned long expires)
650 {
651 struct fnhe_hash_bucket *hash;
652 struct fib_nh_exception *fnhe;
653 struct rtable *rt;
654 unsigned int i;
655 int depth;
656 u32 hval = fnhe_hashfun(daddr);
657
658 spin_lock_bh(&fnhe_lock);
659
660 hash = rcu_dereference(nh->nh_exceptions);
661 if (!hash) {
662 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
663 if (!hash)
664 goto out_unlock;
665 rcu_assign_pointer(nh->nh_exceptions, hash);
666 }
667
668 hash += hval;
669
670 depth = 0;
671 for (fnhe = rcu_dereference(hash->chain); fnhe;
672 fnhe = rcu_dereference(fnhe->fnhe_next)) {
673 if (fnhe->fnhe_daddr == daddr)
674 break;
675 depth++;
676 }
677
678 if (fnhe) {
679 if (gw)
680 fnhe->fnhe_gw = gw;
681 if (pmtu) {
682 fnhe->fnhe_pmtu = pmtu;
683 fnhe->fnhe_expires = max(1UL, expires);
684 }
685 /* Update all cached dsts too */
686 rt = rcu_dereference(fnhe->fnhe_rth_input);
687 if (rt)
688 fill_route_from_fnhe(rt, fnhe);
689 rt = rcu_dereference(fnhe->fnhe_rth_output);
690 if (rt)
691 fill_route_from_fnhe(rt, fnhe);
692 } else {
693 if (depth > FNHE_RECLAIM_DEPTH)
694 fnhe = fnhe_oldest(hash);
695 else {
696 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
697 if (!fnhe)
698 goto out_unlock;
699
700 fnhe->fnhe_next = hash->chain;
701 rcu_assign_pointer(hash->chain, fnhe);
702 }
703 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
704 fnhe->fnhe_daddr = daddr;
705 fnhe->fnhe_gw = gw;
706 fnhe->fnhe_pmtu = pmtu;
707 fnhe->fnhe_expires = expires;
708
709 /* Exception created; mark the cached routes for the nexthop
710 * stale, so anyone caching it rechecks if this exception
711 * applies to them.
712 */
713 rt = rcu_dereference(nh->nh_rth_input);
714 if (rt)
715 rt->dst.obsolete = DST_OBSOLETE_KILL;
716
717 for_each_possible_cpu(i) {
718 struct rtable __rcu **prt;
719 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
720 rt = rcu_dereference(*prt);
721 if (rt)
722 rt->dst.obsolete = DST_OBSOLETE_KILL;
723 }
724 }
725
726 fnhe->fnhe_stamp = jiffies;
727
728 out_unlock:
729 spin_unlock_bh(&fnhe_lock);
730 }
731
732 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
733 bool kill_route)
734 {
735 __be32 new_gw = icmp_hdr(skb)->un.gateway;
736 __be32 old_gw = ip_hdr(skb)->saddr;
737 struct net_device *dev = skb->dev;
738 struct in_device *in_dev;
739 struct fib_result res;
740 struct neighbour *n;
741 struct net *net;
742
743 switch (icmp_hdr(skb)->code & 7) {
744 case ICMP_REDIR_NET:
745 case ICMP_REDIR_NETTOS:
746 case ICMP_REDIR_HOST:
747 case ICMP_REDIR_HOSTTOS:
748 break;
749
750 default:
751 return;
752 }
753
754 if (rt->rt_gateway != old_gw)
755 return;
756
757 in_dev = __in_dev_get_rcu(dev);
758 if (!in_dev)
759 return;
760
761 net = dev_net(dev);
762 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
763 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
764 ipv4_is_zeronet(new_gw))
765 goto reject_redirect;
766
767 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
768 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
769 goto reject_redirect;
770 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
771 goto reject_redirect;
772 } else {
773 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
774 goto reject_redirect;
775 }
776
777 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
778 if (!n)
779 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
780 if (!IS_ERR(n)) {
781 if (!(n->nud_state & NUD_VALID)) {
782 neigh_event_send(n, NULL);
783 } else {
784 if (fib_lookup(net, fl4, &res, 0) == 0) {
785 struct fib_nh *nh = &FIB_RES_NH(res);
786
787 update_or_create_fnhe(nh, fl4->daddr, new_gw,
788 0, jiffies + ip_rt_gc_timeout);
789 }
790 if (kill_route)
791 rt->dst.obsolete = DST_OBSOLETE_KILL;
792 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
793 }
794 neigh_release(n);
795 }
796 return;
797
798 reject_redirect:
799 #ifdef CONFIG_IP_ROUTE_VERBOSE
800 if (IN_DEV_LOG_MARTIANS(in_dev)) {
801 const struct iphdr *iph = (const struct iphdr *) skb->data;
802 __be32 daddr = iph->daddr;
803 __be32 saddr = iph->saddr;
804
805 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
806 " Advised path = %pI4 -> %pI4\n",
807 &old_gw, dev->name, &new_gw,
808 &saddr, &daddr);
809 }
810 #endif
811 ;
812 }
813
814 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
815 {
816 struct rtable *rt;
817 struct flowi4 fl4;
818 const struct iphdr *iph = (const struct iphdr *) skb->data;
819 struct net *net = dev_net(skb->dev);
820 int oif = skb->dev->ifindex;
821 u8 tos = RT_TOS(iph->tos);
822 u8 prot = iph->protocol;
823 u32 mark = skb->mark;
824
825 rt = (struct rtable *) dst;
826
827 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
828 __ip_do_redirect(rt, skb, &fl4, true);
829 }
830
831 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
832 {
833 struct rtable *rt = (struct rtable *)dst;
834 struct dst_entry *ret = dst;
835
836 if (rt) {
837 if (dst->obsolete > 0) {
838 ip_rt_put(rt);
839 ret = NULL;
840 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
841 rt->dst.expires) {
842 ip_rt_put(rt);
843 ret = NULL;
844 }
845 }
846 return ret;
847 }
848
849 /*
850 * Algorithm:
851 * 1. The first ip_rt_redirect_number redirects are sent
852 * with exponential backoff, then we stop sending them at all,
853 * assuming that the host ignores our redirects.
854 * 2. If we did not see packets requiring redirects
855 * during ip_rt_redirect_silence, we assume that the host
856 * forgot redirected route and start to send redirects again.
857 *
858 * This algorithm is much cheaper and more intelligent than dumb load limiting
859 * in icmp.c.
860 *
861 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
862 * and "frag. need" (breaks PMTU discovery) in icmp.c.
863 */
864
865 void ip_rt_send_redirect(struct sk_buff *skb)
866 {
867 struct rtable *rt = skb_rtable(skb);
868 struct in_device *in_dev;
869 struct inet_peer *peer;
870 struct net *net;
871 int log_martians;
872 int vif;
873
874 rcu_read_lock();
875 in_dev = __in_dev_get_rcu(rt->dst.dev);
876 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
877 rcu_read_unlock();
878 return;
879 }
880 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
881 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
882 rcu_read_unlock();
883
884 net = dev_net(rt->dst.dev);
885 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
886 if (!peer) {
887 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
888 rt_nexthop(rt, ip_hdr(skb)->daddr));
889 return;
890 }
891
892 /* No redirected packets during ip_rt_redirect_silence;
893 * reset the algorithm.
894 */
895 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
896 peer->rate_tokens = 0;
897
898 /* Too many ignored redirects; do not send anything
899 * set dst.rate_last to the last seen redirected packet.
900 */
901 if (peer->rate_tokens >= ip_rt_redirect_number) {
902 peer->rate_last = jiffies;
903 goto out_put_peer;
904 }
905
906 /* Check for load limit; set rate_last to the latest sent
907 * redirect.
908 */
909 if (peer->rate_tokens == 0 ||
910 time_after(jiffies,
911 (peer->rate_last +
912 (ip_rt_redirect_load << peer->rate_tokens)))) {
913 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
914
915 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
916 peer->rate_last = jiffies;
917 ++peer->rate_tokens;
918 #ifdef CONFIG_IP_ROUTE_VERBOSE
919 if (log_martians &&
920 peer->rate_tokens == ip_rt_redirect_number)
921 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
922 &ip_hdr(skb)->saddr, inet_iif(skb),
923 &ip_hdr(skb)->daddr, &gw);
924 #endif
925 }
926 out_put_peer:
927 inet_putpeer(peer);
928 }
929
930 static int ip_error(struct sk_buff *skb)
931 {
932 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
933 struct rtable *rt = skb_rtable(skb);
934 struct inet_peer *peer;
935 unsigned long now;
936 struct net *net;
937 bool send;
938 int code;
939
940 /* IP on this device is disabled. */
941 if (!in_dev)
942 goto out;
943
944 net = dev_net(rt->dst.dev);
945 if (!IN_DEV_FORWARD(in_dev)) {
946 switch (rt->dst.error) {
947 case EHOSTUNREACH:
948 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
949 break;
950
951 case ENETUNREACH:
952 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
953 break;
954 }
955 goto out;
956 }
957
958 switch (rt->dst.error) {
959 case EINVAL:
960 default:
961 goto out;
962 case EHOSTUNREACH:
963 code = ICMP_HOST_UNREACH;
964 break;
965 case ENETUNREACH:
966 code = ICMP_NET_UNREACH;
967 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
968 break;
969 case EACCES:
970 code = ICMP_PKT_FILTERED;
971 break;
972 }
973
974 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
975 l3mdev_master_ifindex(skb->dev), 1);
976
977 send = true;
978 if (peer) {
979 now = jiffies;
980 peer->rate_tokens += now - peer->rate_last;
981 if (peer->rate_tokens > ip_rt_error_burst)
982 peer->rate_tokens = ip_rt_error_burst;
983 peer->rate_last = now;
984 if (peer->rate_tokens >= ip_rt_error_cost)
985 peer->rate_tokens -= ip_rt_error_cost;
986 else
987 send = false;
988 inet_putpeer(peer);
989 }
990 if (send)
991 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
992
993 out: kfree_skb(skb);
994 return 0;
995 }
996
997 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
998 {
999 struct dst_entry *dst = &rt->dst;
1000 struct fib_result res;
1001
1002 if (dst_metric_locked(dst, RTAX_MTU))
1003 return;
1004
1005 if (ipv4_mtu(dst) < mtu)
1006 return;
1007
1008 if (mtu < ip_rt_min_pmtu)
1009 mtu = ip_rt_min_pmtu;
1010
1011 if (rt->rt_pmtu == mtu &&
1012 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1013 return;
1014
1015 rcu_read_lock();
1016 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1017 struct fib_nh *nh = &FIB_RES_NH(res);
1018
1019 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
1020 jiffies + ip_rt_mtu_expires);
1021 }
1022 rcu_read_unlock();
1023 }
1024
1025 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1026 struct sk_buff *skb, u32 mtu)
1027 {
1028 struct rtable *rt = (struct rtable *) dst;
1029 struct flowi4 fl4;
1030
1031 ip_rt_build_flow_key(&fl4, sk, skb);
1032 __ip_rt_update_pmtu(rt, &fl4, mtu);
1033 }
1034
1035 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1036 int oif, u32 mark, u8 protocol, int flow_flags)
1037 {
1038 const struct iphdr *iph = (const struct iphdr *) skb->data;
1039 struct flowi4 fl4;
1040 struct rtable *rt;
1041
1042 if (!mark)
1043 mark = IP4_REPLY_MARK(net, skb->mark);
1044
1045 __build_flow_key(net, &fl4, NULL, iph, oif,
1046 RT_TOS(iph->tos), protocol, mark, flow_flags);
1047 rt = __ip_route_output_key(net, &fl4);
1048 if (!IS_ERR(rt)) {
1049 __ip_rt_update_pmtu(rt, &fl4, mtu);
1050 ip_rt_put(rt);
1051 }
1052 }
1053 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1054
1055 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1056 {
1057 const struct iphdr *iph = (const struct iphdr *) skb->data;
1058 struct flowi4 fl4;
1059 struct rtable *rt;
1060
1061 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1062
1063 if (!fl4.flowi4_mark)
1064 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1065
1066 rt = __ip_route_output_key(sock_net(sk), &fl4);
1067 if (!IS_ERR(rt)) {
1068 __ip_rt_update_pmtu(rt, &fl4, mtu);
1069 ip_rt_put(rt);
1070 }
1071 }
1072
1073 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1074 {
1075 const struct iphdr *iph = (const struct iphdr *) skb->data;
1076 struct flowi4 fl4;
1077 struct rtable *rt;
1078 struct dst_entry *odst = NULL;
1079 bool new = false;
1080 struct net *net = sock_net(sk);
1081
1082 bh_lock_sock(sk);
1083
1084 if (!ip_sk_accept_pmtu(sk))
1085 goto out;
1086
1087 odst = sk_dst_get(sk);
1088
1089 if (sock_owned_by_user(sk) || !odst) {
1090 __ipv4_sk_update_pmtu(skb, sk, mtu);
1091 goto out;
1092 }
1093
1094 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1095
1096 rt = (struct rtable *)odst;
1097 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1098 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1099 if (IS_ERR(rt))
1100 goto out;
1101
1102 new = true;
1103 }
1104
1105 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1106
1107 if (!dst_check(&rt->dst, 0)) {
1108 if (new)
1109 dst_release(&rt->dst);
1110
1111 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1112 if (IS_ERR(rt))
1113 goto out;
1114
1115 new = true;
1116 }
1117
1118 if (new)
1119 sk_dst_set(sk, &rt->dst);
1120
1121 out:
1122 bh_unlock_sock(sk);
1123 dst_release(odst);
1124 }
1125 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1126
1127 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1128 int oif, u32 mark, u8 protocol, int flow_flags)
1129 {
1130 const struct iphdr *iph = (const struct iphdr *) skb->data;
1131 struct flowi4 fl4;
1132 struct rtable *rt;
1133
1134 __build_flow_key(net, &fl4, NULL, iph, oif,
1135 RT_TOS(iph->tos), protocol, mark, flow_flags);
1136 rt = __ip_route_output_key(net, &fl4);
1137 if (!IS_ERR(rt)) {
1138 __ip_do_redirect(rt, skb, &fl4, false);
1139 ip_rt_put(rt);
1140 }
1141 }
1142 EXPORT_SYMBOL_GPL(ipv4_redirect);
1143
1144 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1145 {
1146 const struct iphdr *iph = (const struct iphdr *) skb->data;
1147 struct flowi4 fl4;
1148 struct rtable *rt;
1149 struct net *net = sock_net(sk);
1150
1151 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1152 rt = __ip_route_output_key(net, &fl4);
1153 if (!IS_ERR(rt)) {
1154 __ip_do_redirect(rt, skb, &fl4, false);
1155 ip_rt_put(rt);
1156 }
1157 }
1158 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1159
1160 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1161 {
1162 struct rtable *rt = (struct rtable *) dst;
1163
1164 /* All IPV4 dsts are created with ->obsolete set to the value
1165 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1166 * into this function always.
1167 *
1168 * When a PMTU/redirect information update invalidates a route,
1169 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1170 * DST_OBSOLETE_DEAD by dst_free().
1171 */
1172 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1173 return NULL;
1174 return dst;
1175 }
1176
1177 static void ipv4_link_failure(struct sk_buff *skb)
1178 {
1179 struct rtable *rt;
1180
1181 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1182
1183 rt = skb_rtable(skb);
1184 if (rt)
1185 dst_set_expires(&rt->dst, 0);
1186 }
1187
1188 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1189 {
1190 pr_debug("%s: %pI4 -> %pI4, %s\n",
1191 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1192 skb->dev ? skb->dev->name : "?");
1193 kfree_skb(skb);
1194 WARN_ON(1);
1195 return 0;
1196 }
1197
1198 /*
1199 We do not cache source address of outgoing interface,
1200 because it is used only by IP RR, TS and SRR options,
1201 so that it out of fast path.
1202
1203 BTW remember: "addr" is allowed to be not aligned
1204 in IP options!
1205 */
1206
1207 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1208 {
1209 __be32 src;
1210
1211 if (rt_is_output_route(rt))
1212 src = ip_hdr(skb)->saddr;
1213 else {
1214 struct fib_result res;
1215 struct flowi4 fl4;
1216 struct iphdr *iph;
1217
1218 iph = ip_hdr(skb);
1219
1220 memset(&fl4, 0, sizeof(fl4));
1221 fl4.daddr = iph->daddr;
1222 fl4.saddr = iph->saddr;
1223 fl4.flowi4_tos = RT_TOS(iph->tos);
1224 fl4.flowi4_oif = rt->dst.dev->ifindex;
1225 fl4.flowi4_iif = skb->dev->ifindex;
1226 fl4.flowi4_mark = skb->mark;
1227
1228 rcu_read_lock();
1229 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1230 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1231 else
1232 src = inet_select_addr(rt->dst.dev,
1233 rt_nexthop(rt, iph->daddr),
1234 RT_SCOPE_UNIVERSE);
1235 rcu_read_unlock();
1236 }
1237 memcpy(addr, &src, 4);
1238 }
1239
1240 #ifdef CONFIG_IP_ROUTE_CLASSID
1241 static void set_class_tag(struct rtable *rt, u32 tag)
1242 {
1243 if (!(rt->dst.tclassid & 0xFFFF))
1244 rt->dst.tclassid |= tag & 0xFFFF;
1245 if (!(rt->dst.tclassid & 0xFFFF0000))
1246 rt->dst.tclassid |= tag & 0xFFFF0000;
1247 }
1248 #endif
1249
1250 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1251 {
1252 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1253 unsigned int advmss = max_t(unsigned int, dst->dev->mtu - header_size,
1254 ip_rt_min_advmss);
1255
1256 return min(advmss, IPV4_MAX_PMTU - header_size);
1257 }
1258
1259 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1260 {
1261 const struct rtable *rt = (const struct rtable *) dst;
1262 unsigned int mtu = rt->rt_pmtu;
1263
1264 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1265 mtu = dst_metric_raw(dst, RTAX_MTU);
1266
1267 if (mtu)
1268 return mtu;
1269
1270 mtu = READ_ONCE(dst->dev->mtu);
1271
1272 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1273 if (rt->rt_uses_gateway && mtu > 576)
1274 mtu = 576;
1275 }
1276
1277 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1278
1279 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1280 }
1281
1282 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1283 {
1284 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1285 struct fib_nh_exception *fnhe;
1286 u32 hval;
1287
1288 if (!hash)
1289 return NULL;
1290
1291 hval = fnhe_hashfun(daddr);
1292
1293 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1294 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1295 if (fnhe->fnhe_daddr == daddr)
1296 return fnhe;
1297 }
1298 return NULL;
1299 }
1300
1301 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1302 __be32 daddr, const bool do_cache)
1303 {
1304 bool ret = false;
1305
1306 spin_lock_bh(&fnhe_lock);
1307
1308 if (daddr == fnhe->fnhe_daddr) {
1309 struct rtable __rcu **porig;
1310 struct rtable *orig;
1311 int genid = fnhe_genid(dev_net(rt->dst.dev));
1312
1313 if (rt_is_input_route(rt))
1314 porig = &fnhe->fnhe_rth_input;
1315 else
1316 porig = &fnhe->fnhe_rth_output;
1317 orig = rcu_dereference(*porig);
1318
1319 if (fnhe->fnhe_genid != genid) {
1320 fnhe->fnhe_genid = genid;
1321 fnhe->fnhe_gw = 0;
1322 fnhe->fnhe_pmtu = 0;
1323 fnhe->fnhe_expires = 0;
1324 fnhe_flush_routes(fnhe);
1325 orig = NULL;
1326 }
1327 fill_route_from_fnhe(rt, fnhe);
1328 if (!rt->rt_gateway)
1329 rt->rt_gateway = daddr;
1330
1331 if (do_cache) {
1332 dst_hold(&rt->dst);
1333 rcu_assign_pointer(*porig, rt);
1334 if (orig) {
1335 dst_dev_put(&orig->dst);
1336 dst_release(&orig->dst);
1337 }
1338 ret = true;
1339 }
1340
1341 fnhe->fnhe_stamp = jiffies;
1342 }
1343 spin_unlock_bh(&fnhe_lock);
1344
1345 return ret;
1346 }
1347
1348 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1349 {
1350 struct rtable *orig, *prev, **p;
1351 bool ret = true;
1352
1353 if (rt_is_input_route(rt)) {
1354 p = (struct rtable **)&nh->nh_rth_input;
1355 } else {
1356 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1357 }
1358 orig = *p;
1359
1360 /* hold dst before doing cmpxchg() to avoid race condition
1361 * on this dst
1362 */
1363 dst_hold(&rt->dst);
1364 prev = cmpxchg(p, orig, rt);
1365 if (prev == orig) {
1366 if (orig) {
1367 dst_dev_put(&orig->dst);
1368 dst_release(&orig->dst);
1369 }
1370 } else {
1371 dst_release(&rt->dst);
1372 ret = false;
1373 }
1374
1375 return ret;
1376 }
1377
1378 struct uncached_list {
1379 spinlock_t lock;
1380 struct list_head head;
1381 };
1382
1383 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1384
1385 static void rt_add_uncached_list(struct rtable *rt)
1386 {
1387 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1388
1389 rt->rt_uncached_list = ul;
1390
1391 spin_lock_bh(&ul->lock);
1392 list_add_tail(&rt->rt_uncached, &ul->head);
1393 spin_unlock_bh(&ul->lock);
1394 }
1395
1396 static void ipv4_dst_destroy(struct dst_entry *dst)
1397 {
1398 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1399 struct rtable *rt = (struct rtable *) dst;
1400
1401 if (p != &dst_default_metrics && atomic_dec_and_test(&p->refcnt))
1402 kfree(p);
1403
1404 if (!list_empty(&rt->rt_uncached)) {
1405 struct uncached_list *ul = rt->rt_uncached_list;
1406
1407 spin_lock_bh(&ul->lock);
1408 list_del(&rt->rt_uncached);
1409 spin_unlock_bh(&ul->lock);
1410 }
1411 }
1412
1413 void rt_flush_dev(struct net_device *dev)
1414 {
1415 struct net *net = dev_net(dev);
1416 struct rtable *rt;
1417 int cpu;
1418
1419 for_each_possible_cpu(cpu) {
1420 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1421
1422 spin_lock_bh(&ul->lock);
1423 list_for_each_entry(rt, &ul->head, rt_uncached) {
1424 if (rt->dst.dev != dev)
1425 continue;
1426 rt->dst.dev = net->loopback_dev;
1427 dev_hold(rt->dst.dev);
1428 dev_put(dev);
1429 }
1430 spin_unlock_bh(&ul->lock);
1431 }
1432 }
1433
1434 static bool rt_cache_valid(const struct rtable *rt)
1435 {
1436 return rt &&
1437 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1438 !rt_is_expired(rt);
1439 }
1440
1441 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1442 const struct fib_result *res,
1443 struct fib_nh_exception *fnhe,
1444 struct fib_info *fi, u16 type, u32 itag,
1445 const bool do_cache)
1446 {
1447 bool cached = false;
1448
1449 if (fi) {
1450 struct fib_nh *nh = &FIB_RES_NH(*res);
1451
1452 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1453 rt->rt_gateway = nh->nh_gw;
1454 rt->rt_uses_gateway = 1;
1455 }
1456 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1457 if (fi->fib_metrics != &dst_default_metrics) {
1458 rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1459 atomic_inc(&fi->fib_metrics->refcnt);
1460 }
1461 #ifdef CONFIG_IP_ROUTE_CLASSID
1462 rt->dst.tclassid = nh->nh_tclassid;
1463 #endif
1464 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1465 if (unlikely(fnhe))
1466 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1467 else if (do_cache)
1468 cached = rt_cache_route(nh, rt);
1469 if (unlikely(!cached)) {
1470 /* Routes we intend to cache in nexthop exception or
1471 * FIB nexthop have the DST_NOCACHE bit clear.
1472 * However, if we are unsuccessful at storing this
1473 * route into the cache we really need to set it.
1474 */
1475 if (!rt->rt_gateway)
1476 rt->rt_gateway = daddr;
1477 rt_add_uncached_list(rt);
1478 }
1479 } else
1480 rt_add_uncached_list(rt);
1481
1482 #ifdef CONFIG_IP_ROUTE_CLASSID
1483 #ifdef CONFIG_IP_MULTIPLE_TABLES
1484 set_class_tag(rt, res->tclassid);
1485 #endif
1486 set_class_tag(rt, itag);
1487 #endif
1488 }
1489
1490 struct rtable *rt_dst_alloc(struct net_device *dev,
1491 unsigned int flags, u16 type,
1492 bool nopolicy, bool noxfrm, bool will_cache)
1493 {
1494 struct rtable *rt;
1495
1496 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1497 (will_cache ? 0 : DST_HOST) |
1498 (nopolicy ? DST_NOPOLICY : 0) |
1499 (noxfrm ? DST_NOXFRM : 0));
1500
1501 if (rt) {
1502 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1503 rt->rt_flags = flags;
1504 rt->rt_type = type;
1505 rt->rt_is_input = 0;
1506 rt->rt_iif = 0;
1507 rt->rt_pmtu = 0;
1508 rt->rt_gateway = 0;
1509 rt->rt_uses_gateway = 0;
1510 rt->rt_table_id = 0;
1511 INIT_LIST_HEAD(&rt->rt_uncached);
1512
1513 rt->dst.output = ip_output;
1514 if (flags & RTCF_LOCAL)
1515 rt->dst.input = ip_local_deliver;
1516 }
1517
1518 return rt;
1519 }
1520 EXPORT_SYMBOL(rt_dst_alloc);
1521
1522 /* called in rcu_read_lock() section */
1523 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1524 u8 tos, struct net_device *dev,
1525 struct in_device *in_dev, u32 *itag)
1526 {
1527 int err;
1528
1529 /* Primary sanity checks. */
1530 if (!in_dev)
1531 return -EINVAL;
1532
1533 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1534 skb->protocol != htons(ETH_P_IP))
1535 return -EINVAL;
1536
1537 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1538 return -EINVAL;
1539
1540 if (ipv4_is_zeronet(saddr)) {
1541 if (!ipv4_is_local_multicast(daddr))
1542 return -EINVAL;
1543 } else {
1544 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1545 in_dev, itag);
1546 if (err < 0)
1547 return err;
1548 }
1549 return 0;
1550 }
1551
1552 /* called in rcu_read_lock() section */
1553 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1554 u8 tos, struct net_device *dev, int our)
1555 {
1556 struct in_device *in_dev = __in_dev_get_rcu(dev);
1557 unsigned int flags = RTCF_MULTICAST;
1558 struct rtable *rth;
1559 u32 itag = 0;
1560 int err;
1561
1562 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1563 if (err)
1564 return err;
1565
1566 if (our)
1567 flags |= RTCF_LOCAL;
1568
1569 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1570 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1571 if (!rth)
1572 return -ENOBUFS;
1573
1574 #ifdef CONFIG_IP_ROUTE_CLASSID
1575 rth->dst.tclassid = itag;
1576 #endif
1577 rth->dst.output = ip_rt_bug;
1578 rth->rt_is_input= 1;
1579
1580 #ifdef CONFIG_IP_MROUTE
1581 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1582 rth->dst.input = ip_mr_input;
1583 #endif
1584 RT_CACHE_STAT_INC(in_slow_mc);
1585
1586 skb_dst_set(skb, &rth->dst);
1587 return 0;
1588 }
1589
1590
1591 static void ip_handle_martian_source(struct net_device *dev,
1592 struct in_device *in_dev,
1593 struct sk_buff *skb,
1594 __be32 daddr,
1595 __be32 saddr)
1596 {
1597 RT_CACHE_STAT_INC(in_martian_src);
1598 #ifdef CONFIG_IP_ROUTE_VERBOSE
1599 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1600 /*
1601 * RFC1812 recommendation, if source is martian,
1602 * the only hint is MAC header.
1603 */
1604 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1605 &daddr, &saddr, dev->name);
1606 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1607 print_hex_dump(KERN_WARNING, "ll header: ",
1608 DUMP_PREFIX_OFFSET, 16, 1,
1609 skb_mac_header(skb),
1610 dev->hard_header_len, true);
1611 }
1612 }
1613 #endif
1614 }
1615
1616 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1617 {
1618 struct fnhe_hash_bucket *hash;
1619 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1620 u32 hval = fnhe_hashfun(daddr);
1621
1622 spin_lock_bh(&fnhe_lock);
1623
1624 hash = rcu_dereference_protected(nh->nh_exceptions,
1625 lockdep_is_held(&fnhe_lock));
1626 hash += hval;
1627
1628 fnhe_p = &hash->chain;
1629 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1630 while (fnhe) {
1631 if (fnhe->fnhe_daddr == daddr) {
1632 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1633 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1634 fnhe_flush_routes(fnhe);
1635 kfree_rcu(fnhe, rcu);
1636 break;
1637 }
1638 fnhe_p = &fnhe->fnhe_next;
1639 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1640 lockdep_is_held(&fnhe_lock));
1641 }
1642
1643 spin_unlock_bh(&fnhe_lock);
1644 }
1645
1646 static void set_lwt_redirect(struct rtable *rth)
1647 {
1648 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1649 rth->dst.lwtstate->orig_output = rth->dst.output;
1650 rth->dst.output = lwtunnel_output;
1651 }
1652
1653 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1654 rth->dst.lwtstate->orig_input = rth->dst.input;
1655 rth->dst.input = lwtunnel_input;
1656 }
1657 }
1658
1659 /* called in rcu_read_lock() section */
1660 static int __mkroute_input(struct sk_buff *skb,
1661 const struct fib_result *res,
1662 struct in_device *in_dev,
1663 __be32 daddr, __be32 saddr, u32 tos)
1664 {
1665 struct fib_nh_exception *fnhe;
1666 struct rtable *rth;
1667 int err;
1668 struct in_device *out_dev;
1669 bool do_cache;
1670 u32 itag = 0;
1671
1672 /* get a working reference to the output device */
1673 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1674 if (!out_dev) {
1675 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1676 return -EINVAL;
1677 }
1678
1679 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1680 in_dev->dev, in_dev, &itag);
1681 if (err < 0) {
1682 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1683 saddr);
1684
1685 goto cleanup;
1686 }
1687
1688 do_cache = res->fi && !itag;
1689 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1690 skb->protocol == htons(ETH_P_IP) &&
1691 (IN_DEV_SHARED_MEDIA(out_dev) ||
1692 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1693 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1694
1695 if (skb->protocol != htons(ETH_P_IP)) {
1696 /* Not IP (i.e. ARP). Do not create route, if it is
1697 * invalid for proxy arp. DNAT routes are always valid.
1698 *
1699 * Proxy arp feature have been extended to allow, ARP
1700 * replies back to the same interface, to support
1701 * Private VLAN switch technologies. See arp.c.
1702 */
1703 if (out_dev == in_dev &&
1704 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1705 err = -EINVAL;
1706 goto cleanup;
1707 }
1708 }
1709
1710 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1711 if (do_cache) {
1712 if (fnhe) {
1713 rth = rcu_dereference(fnhe->fnhe_rth_input);
1714 if (rth && rth->dst.expires &&
1715 time_after(jiffies, rth->dst.expires)) {
1716 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1717 fnhe = NULL;
1718 } else {
1719 goto rt_cache;
1720 }
1721 }
1722
1723 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1724
1725 rt_cache:
1726 if (rt_cache_valid(rth)) {
1727 skb_dst_set_noref(skb, &rth->dst);
1728 goto out;
1729 }
1730 }
1731
1732 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1733 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1734 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1735 if (!rth) {
1736 err = -ENOBUFS;
1737 goto cleanup;
1738 }
1739
1740 rth->rt_is_input = 1;
1741 if (res->table)
1742 rth->rt_table_id = res->table->tb_id;
1743 RT_CACHE_STAT_INC(in_slow_tot);
1744
1745 rth->dst.input = ip_forward;
1746
1747 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1748 do_cache);
1749 set_lwt_redirect(rth);
1750 skb_dst_set(skb, &rth->dst);
1751 out:
1752 err = 0;
1753 cleanup:
1754 return err;
1755 }
1756
1757 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1758 /* To make ICMP packets follow the right flow, the multipath hash is
1759 * calculated from the inner IP addresses.
1760 */
1761 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1762 struct flow_keys *hash_keys)
1763 {
1764 const struct iphdr *outer_iph = ip_hdr(skb);
1765 const struct iphdr *inner_iph;
1766 const struct icmphdr *icmph;
1767 struct iphdr _inner_iph;
1768 struct icmphdr _icmph;
1769
1770 hash_keys->addrs.v4addrs.src = outer_iph->saddr;
1771 hash_keys->addrs.v4addrs.dst = outer_iph->daddr;
1772 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1773 return;
1774
1775 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1776 return;
1777
1778 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1779 &_icmph);
1780 if (!icmph)
1781 return;
1782
1783 if (icmph->type != ICMP_DEST_UNREACH &&
1784 icmph->type != ICMP_REDIRECT &&
1785 icmph->type != ICMP_TIME_EXCEEDED &&
1786 icmph->type != ICMP_PARAMETERPROB)
1787 return;
1788
1789 inner_iph = skb_header_pointer(skb,
1790 outer_iph->ihl * 4 + sizeof(_icmph),
1791 sizeof(_inner_iph), &_inner_iph);
1792 if (!inner_iph)
1793 return;
1794 hash_keys->addrs.v4addrs.src = inner_iph->saddr;
1795 hash_keys->addrs.v4addrs.dst = inner_iph->daddr;
1796 }
1797
1798 /* if skb is set it will be used and fl4 can be NULL */
1799 int fib_multipath_hash(const struct fib_info *fi, const struct flowi4 *fl4,
1800 const struct sk_buff *skb)
1801 {
1802 struct net *net = fi->fib_net;
1803 struct flow_keys hash_keys;
1804 u32 mhash;
1805
1806 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1807 case 0:
1808 memset(&hash_keys, 0, sizeof(hash_keys));
1809 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1810 if (skb) {
1811 ip_multipath_l3_keys(skb, &hash_keys);
1812 } else {
1813 hash_keys.addrs.v4addrs.src = fl4->saddr;
1814 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1815 }
1816 break;
1817 case 1:
1818 /* skb is currently provided only when forwarding */
1819 if (skb) {
1820 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1821 struct flow_keys keys;
1822
1823 /* short-circuit if we already have L4 hash present */
1824 if (skb->l4_hash)
1825 return skb_get_hash_raw(skb) >> 1;
1826 memset(&hash_keys, 0, sizeof(hash_keys));
1827 skb_flow_dissect_flow_keys(skb, &keys, flag);
1828 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1829 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1830 hash_keys.ports.src = keys.ports.src;
1831 hash_keys.ports.dst = keys.ports.dst;
1832 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1833 } else {
1834 memset(&hash_keys, 0, sizeof(hash_keys));
1835 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1836 hash_keys.addrs.v4addrs.src = fl4->saddr;
1837 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1838 hash_keys.ports.src = fl4->fl4_sport;
1839 hash_keys.ports.dst = fl4->fl4_dport;
1840 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1841 }
1842 break;
1843 }
1844 mhash = flow_hash_from_keys(&hash_keys);
1845
1846 return mhash >> 1;
1847 }
1848 EXPORT_SYMBOL_GPL(fib_multipath_hash);
1849 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1850
1851 static int ip_mkroute_input(struct sk_buff *skb,
1852 struct fib_result *res,
1853 struct in_device *in_dev,
1854 __be32 daddr, __be32 saddr, u32 tos)
1855 {
1856 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1857 if (res->fi && res->fi->fib_nhs > 1) {
1858 int h = fib_multipath_hash(res->fi, NULL, skb);
1859
1860 fib_select_multipath(res, h);
1861 }
1862 #endif
1863
1864 /* create a routing cache entry */
1865 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1866 }
1867
1868 /*
1869 * NOTE. We drop all the packets that has local source
1870 * addresses, because every properly looped back packet
1871 * must have correct destination already attached by output routine.
1872 *
1873 * Such approach solves two big problems:
1874 * 1. Not simplex devices are handled properly.
1875 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1876 * called with rcu_read_lock()
1877 */
1878
1879 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1880 u8 tos, struct net_device *dev,
1881 struct fib_result *res)
1882 {
1883 struct in_device *in_dev = __in_dev_get_rcu(dev);
1884 struct ip_tunnel_info *tun_info;
1885 struct flowi4 fl4;
1886 unsigned int flags = 0;
1887 u32 itag = 0;
1888 struct rtable *rth;
1889 int err = -EINVAL;
1890 struct net *net = dev_net(dev);
1891 bool do_cache;
1892
1893 /* IP on this device is disabled. */
1894
1895 if (!in_dev)
1896 goto out;
1897
1898 /* Check for the most weird martians, which can be not detected
1899 by fib_lookup.
1900 */
1901
1902 tun_info = skb_tunnel_info(skb);
1903 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1904 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1905 else
1906 fl4.flowi4_tun_key.tun_id = 0;
1907 skb_dst_drop(skb);
1908
1909 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1910 goto martian_source;
1911
1912 res->fi = NULL;
1913 res->table = NULL;
1914 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1915 goto brd_input;
1916
1917 /* Accept zero addresses only to limited broadcast;
1918 * I even do not know to fix it or not. Waiting for complains :-)
1919 */
1920 if (ipv4_is_zeronet(saddr))
1921 goto martian_source;
1922
1923 if (ipv4_is_zeronet(daddr))
1924 goto martian_destination;
1925
1926 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1927 * and call it once if daddr or/and saddr are loopback addresses
1928 */
1929 if (ipv4_is_loopback(daddr)) {
1930 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1931 goto martian_destination;
1932 } else if (ipv4_is_loopback(saddr)) {
1933 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1934 goto martian_source;
1935 }
1936
1937 /*
1938 * Now we are ready to route packet.
1939 */
1940 fl4.flowi4_oif = 0;
1941 fl4.flowi4_iif = dev->ifindex;
1942 fl4.flowi4_mark = skb->mark;
1943 fl4.flowi4_tos = tos;
1944 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1945 fl4.flowi4_flags = 0;
1946 fl4.daddr = daddr;
1947 fl4.saddr = saddr;
1948 fl4.flowi4_uid = sock_net_uid(net, NULL);
1949 err = fib_lookup(net, &fl4, res, 0);
1950 if (err != 0) {
1951 if (!IN_DEV_FORWARD(in_dev))
1952 err = -EHOSTUNREACH;
1953 goto no_route;
1954 }
1955
1956 if (res->type == RTN_BROADCAST)
1957 goto brd_input;
1958
1959 if (res->type == RTN_LOCAL) {
1960 err = fib_validate_source(skb, saddr, daddr, tos,
1961 0, dev, in_dev, &itag);
1962 if (err < 0)
1963 goto martian_source;
1964 goto local_input;
1965 }
1966
1967 if (!IN_DEV_FORWARD(in_dev)) {
1968 err = -EHOSTUNREACH;
1969 goto no_route;
1970 }
1971 if (res->type != RTN_UNICAST)
1972 goto martian_destination;
1973
1974 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1975 out: return err;
1976
1977 brd_input:
1978 if (skb->protocol != htons(ETH_P_IP))
1979 goto e_inval;
1980
1981 if (!ipv4_is_zeronet(saddr)) {
1982 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1983 in_dev, &itag);
1984 if (err < 0)
1985 goto martian_source;
1986 }
1987 flags |= RTCF_BROADCAST;
1988 res->type = RTN_BROADCAST;
1989 RT_CACHE_STAT_INC(in_brd);
1990
1991 local_input:
1992 do_cache = false;
1993 if (res->fi) {
1994 if (!itag) {
1995 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1996 if (rt_cache_valid(rth)) {
1997 skb_dst_set_noref(skb, &rth->dst);
1998 err = 0;
1999 goto out;
2000 }
2001 do_cache = true;
2002 }
2003 }
2004
2005 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2006 flags | RTCF_LOCAL, res->type,
2007 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2008 if (!rth)
2009 goto e_nobufs;
2010
2011 rth->dst.output= ip_rt_bug;
2012 #ifdef CONFIG_IP_ROUTE_CLASSID
2013 rth->dst.tclassid = itag;
2014 #endif
2015 rth->rt_is_input = 1;
2016 if (res->table)
2017 rth->rt_table_id = res->table->tb_id;
2018
2019 RT_CACHE_STAT_INC(in_slow_tot);
2020 if (res->type == RTN_UNREACHABLE) {
2021 rth->dst.input= ip_error;
2022 rth->dst.error= -err;
2023 rth->rt_flags &= ~RTCF_LOCAL;
2024 }
2025
2026 if (do_cache) {
2027 struct fib_nh *nh = &FIB_RES_NH(*res);
2028
2029 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2030 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2031 WARN_ON(rth->dst.input == lwtunnel_input);
2032 rth->dst.lwtstate->orig_input = rth->dst.input;
2033 rth->dst.input = lwtunnel_input;
2034 }
2035
2036 if (unlikely(!rt_cache_route(nh, rth)))
2037 rt_add_uncached_list(rth);
2038 }
2039 skb_dst_set(skb, &rth->dst);
2040 err = 0;
2041 goto out;
2042
2043 no_route:
2044 RT_CACHE_STAT_INC(in_no_route);
2045 res->type = RTN_UNREACHABLE;
2046 res->fi = NULL;
2047 res->table = NULL;
2048 goto local_input;
2049
2050 /*
2051 * Do not cache martian addresses: they should be logged (RFC1812)
2052 */
2053 martian_destination:
2054 RT_CACHE_STAT_INC(in_martian_dst);
2055 #ifdef CONFIG_IP_ROUTE_VERBOSE
2056 if (IN_DEV_LOG_MARTIANS(in_dev))
2057 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2058 &daddr, &saddr, dev->name);
2059 #endif
2060
2061 e_inval:
2062 err = -EINVAL;
2063 goto out;
2064
2065 e_nobufs:
2066 err = -ENOBUFS;
2067 goto out;
2068
2069 martian_source:
2070 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2071 goto out;
2072 }
2073
2074 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2075 u8 tos, struct net_device *dev)
2076 {
2077 struct fib_result res;
2078 int err;
2079
2080 tos &= IPTOS_RT_MASK;
2081 rcu_read_lock();
2082 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2083 rcu_read_unlock();
2084
2085 return err;
2086 }
2087 EXPORT_SYMBOL(ip_route_input_noref);
2088
2089 /* called with rcu_read_lock held */
2090 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2091 u8 tos, struct net_device *dev, struct fib_result *res)
2092 {
2093 /* Multicast recognition logic is moved from route cache to here.
2094 The problem was that too many Ethernet cards have broken/missing
2095 hardware multicast filters :-( As result the host on multicasting
2096 network acquires a lot of useless route cache entries, sort of
2097 SDR messages from all the world. Now we try to get rid of them.
2098 Really, provided software IP multicast filter is organized
2099 reasonably (at least, hashed), it does not result in a slowdown
2100 comparing with route cache reject entries.
2101 Note, that multicast routers are not affected, because
2102 route cache entry is created eventually.
2103 */
2104 if (ipv4_is_multicast(daddr)) {
2105 struct in_device *in_dev = __in_dev_get_rcu(dev);
2106 int our = 0;
2107 int err = -EINVAL;
2108
2109 if (in_dev)
2110 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2111 ip_hdr(skb)->protocol);
2112
2113 /* check l3 master if no match yet */
2114 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2115 struct in_device *l3_in_dev;
2116
2117 l3_in_dev = __in_dev_get_rcu(skb->dev);
2118 if (l3_in_dev)
2119 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2120 ip_hdr(skb)->protocol);
2121 }
2122
2123 if (our
2124 #ifdef CONFIG_IP_MROUTE
2125 ||
2126 (!ipv4_is_local_multicast(daddr) &&
2127 IN_DEV_MFORWARD(in_dev))
2128 #endif
2129 ) {
2130 err = ip_route_input_mc(skb, daddr, saddr,
2131 tos, dev, our);
2132 }
2133 return err;
2134 }
2135
2136 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2137 }
2138
2139 /* called with rcu_read_lock() */
2140 static struct rtable *__mkroute_output(const struct fib_result *res,
2141 const struct flowi4 *fl4, int orig_oif,
2142 struct net_device *dev_out,
2143 unsigned int flags)
2144 {
2145 struct fib_info *fi = res->fi;
2146 struct fib_nh_exception *fnhe;
2147 struct in_device *in_dev;
2148 u16 type = res->type;
2149 struct rtable *rth;
2150 bool do_cache;
2151
2152 in_dev = __in_dev_get_rcu(dev_out);
2153 if (!in_dev)
2154 return ERR_PTR(-EINVAL);
2155
2156 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2157 if (ipv4_is_loopback(fl4->saddr) &&
2158 !(dev_out->flags & IFF_LOOPBACK) &&
2159 !netif_is_l3_master(dev_out))
2160 return ERR_PTR(-EINVAL);
2161
2162 if (ipv4_is_lbcast(fl4->daddr))
2163 type = RTN_BROADCAST;
2164 else if (ipv4_is_multicast(fl4->daddr))
2165 type = RTN_MULTICAST;
2166 else if (ipv4_is_zeronet(fl4->daddr))
2167 return ERR_PTR(-EINVAL);
2168
2169 if (dev_out->flags & IFF_LOOPBACK)
2170 flags |= RTCF_LOCAL;
2171
2172 do_cache = true;
2173 if (type == RTN_BROADCAST) {
2174 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2175 fi = NULL;
2176 } else if (type == RTN_MULTICAST) {
2177 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2178 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2179 fl4->flowi4_proto))
2180 flags &= ~RTCF_LOCAL;
2181 else
2182 do_cache = false;
2183 /* If multicast route do not exist use
2184 * default one, but do not gateway in this case.
2185 * Yes, it is hack.
2186 */
2187 if (fi && res->prefixlen < 4)
2188 fi = NULL;
2189 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2190 (orig_oif != dev_out->ifindex)) {
2191 /* For local routes that require a particular output interface
2192 * we do not want to cache the result. Caching the result
2193 * causes incorrect behaviour when there are multiple source
2194 * addresses on the interface, the end result being that if the
2195 * intended recipient is waiting on that interface for the
2196 * packet he won't receive it because it will be delivered on
2197 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2198 * be set to the loopback interface as well.
2199 */
2200 fi = NULL;
2201 }
2202
2203 fnhe = NULL;
2204 do_cache &= fi != NULL;
2205 if (do_cache) {
2206 struct rtable __rcu **prth;
2207 struct fib_nh *nh = &FIB_RES_NH(*res);
2208
2209 fnhe = find_exception(nh, fl4->daddr);
2210 if (fnhe) {
2211 prth = &fnhe->fnhe_rth_output;
2212 rth = rcu_dereference(*prth);
2213 if (rth && rth->dst.expires &&
2214 time_after(jiffies, rth->dst.expires)) {
2215 ip_del_fnhe(nh, fl4->daddr);
2216 fnhe = NULL;
2217 } else {
2218 goto rt_cache;
2219 }
2220 }
2221
2222 if (unlikely(fl4->flowi4_flags &
2223 FLOWI_FLAG_KNOWN_NH &&
2224 !(nh->nh_gw &&
2225 nh->nh_scope == RT_SCOPE_LINK))) {
2226 do_cache = false;
2227 goto add;
2228 }
2229 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2230 rth = rcu_dereference(*prth);
2231
2232 rt_cache:
2233 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2234 return rth;
2235 }
2236
2237 add:
2238 rth = rt_dst_alloc(dev_out, flags, type,
2239 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2240 IN_DEV_CONF_GET(in_dev, NOXFRM),
2241 do_cache);
2242 if (!rth)
2243 return ERR_PTR(-ENOBUFS);
2244
2245 rth->rt_iif = orig_oif ? : 0;
2246 if (res->table)
2247 rth->rt_table_id = res->table->tb_id;
2248
2249 RT_CACHE_STAT_INC(out_slow_tot);
2250
2251 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2252 if (flags & RTCF_LOCAL &&
2253 !(dev_out->flags & IFF_LOOPBACK)) {
2254 rth->dst.output = ip_mc_output;
2255 RT_CACHE_STAT_INC(out_slow_mc);
2256 }
2257 #ifdef CONFIG_IP_MROUTE
2258 if (type == RTN_MULTICAST) {
2259 if (IN_DEV_MFORWARD(in_dev) &&
2260 !ipv4_is_local_multicast(fl4->daddr)) {
2261 rth->dst.input = ip_mr_input;
2262 rth->dst.output = ip_mc_output;
2263 }
2264 }
2265 #endif
2266 }
2267
2268 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2269 set_lwt_redirect(rth);
2270
2271 return rth;
2272 }
2273
2274 /*
2275 * Major route resolver routine.
2276 */
2277
2278 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2279 const struct sk_buff *skb)
2280 {
2281 __u8 tos = RT_FL_TOS(fl4);
2282 struct fib_result res;
2283 struct rtable *rth;
2284
2285 res.tclassid = 0;
2286 res.fi = NULL;
2287 res.table = NULL;
2288
2289 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2290 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2291 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2292 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2293
2294 rcu_read_lock();
2295 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2296 rcu_read_unlock();
2297
2298 return rth;
2299 }
2300 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2301
2302 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2303 struct fib_result *res,
2304 const struct sk_buff *skb)
2305 {
2306 struct net_device *dev_out = NULL;
2307 int orig_oif = fl4->flowi4_oif;
2308 unsigned int flags = 0;
2309 struct rtable *rth;
2310 int err = -ENETUNREACH;
2311
2312 if (fl4->saddr) {
2313 rth = ERR_PTR(-EINVAL);
2314 if (ipv4_is_multicast(fl4->saddr) ||
2315 ipv4_is_lbcast(fl4->saddr) ||
2316 ipv4_is_zeronet(fl4->saddr))
2317 goto out;
2318
2319 /* I removed check for oif == dev_out->oif here.
2320 It was wrong for two reasons:
2321 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2322 is assigned to multiple interfaces.
2323 2. Moreover, we are allowed to send packets with saddr
2324 of another iface. --ANK
2325 */
2326
2327 if (fl4->flowi4_oif == 0 &&
2328 (ipv4_is_multicast(fl4->daddr) ||
2329 ipv4_is_lbcast(fl4->daddr))) {
2330 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2331 dev_out = __ip_dev_find(net, fl4->saddr, false);
2332 if (!dev_out)
2333 goto out;
2334
2335 /* Special hack: user can direct multicasts
2336 and limited broadcast via necessary interface
2337 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2338 This hack is not just for fun, it allows
2339 vic,vat and friends to work.
2340 They bind socket to loopback, set ttl to zero
2341 and expect that it will work.
2342 From the viewpoint of routing cache they are broken,
2343 because we are not allowed to build multicast path
2344 with loopback source addr (look, routing cache
2345 cannot know, that ttl is zero, so that packet
2346 will not leave this host and route is valid).
2347 Luckily, this hack is good workaround.
2348 */
2349
2350 fl4->flowi4_oif = dev_out->ifindex;
2351 goto make_route;
2352 }
2353
2354 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2355 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2356 if (!__ip_dev_find(net, fl4->saddr, false))
2357 goto out;
2358 }
2359 }
2360
2361
2362 if (fl4->flowi4_oif) {
2363 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2364 rth = ERR_PTR(-ENODEV);
2365 if (!dev_out)
2366 goto out;
2367
2368 /* RACE: Check return value of inet_select_addr instead. */
2369 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2370 rth = ERR_PTR(-ENETUNREACH);
2371 goto out;
2372 }
2373 if (ipv4_is_local_multicast(fl4->daddr) ||
2374 ipv4_is_lbcast(fl4->daddr) ||
2375 fl4->flowi4_proto == IPPROTO_IGMP) {
2376 if (!fl4->saddr)
2377 fl4->saddr = inet_select_addr(dev_out, 0,
2378 RT_SCOPE_LINK);
2379 goto make_route;
2380 }
2381 if (!fl4->saddr) {
2382 if (ipv4_is_multicast(fl4->daddr))
2383 fl4->saddr = inet_select_addr(dev_out, 0,
2384 fl4->flowi4_scope);
2385 else if (!fl4->daddr)
2386 fl4->saddr = inet_select_addr(dev_out, 0,
2387 RT_SCOPE_HOST);
2388 }
2389 }
2390
2391 if (!fl4->daddr) {
2392 fl4->daddr = fl4->saddr;
2393 if (!fl4->daddr)
2394 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2395 dev_out = net->loopback_dev;
2396 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2397 res->type = RTN_LOCAL;
2398 flags |= RTCF_LOCAL;
2399 goto make_route;
2400 }
2401
2402 err = fib_lookup(net, fl4, res, 0);
2403 if (err) {
2404 res->fi = NULL;
2405 res->table = NULL;
2406 if (fl4->flowi4_oif &&
2407 (ipv4_is_multicast(fl4->daddr) ||
2408 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2409 /* Apparently, routing tables are wrong. Assume,
2410 that the destination is on link.
2411
2412 WHY? DW.
2413 Because we are allowed to send to iface
2414 even if it has NO routes and NO assigned
2415 addresses. When oif is specified, routing
2416 tables are looked up with only one purpose:
2417 to catch if destination is gatewayed, rather than
2418 direct. Moreover, if MSG_DONTROUTE is set,
2419 we send packet, ignoring both routing tables
2420 and ifaddr state. --ANK
2421
2422
2423 We could make it even if oif is unknown,
2424 likely IPv6, but we do not.
2425 */
2426
2427 if (fl4->saddr == 0)
2428 fl4->saddr = inet_select_addr(dev_out, 0,
2429 RT_SCOPE_LINK);
2430 res->type = RTN_UNICAST;
2431 goto make_route;
2432 }
2433 rth = ERR_PTR(err);
2434 goto out;
2435 }
2436
2437 if (res->type == RTN_LOCAL) {
2438 if (!fl4->saddr) {
2439 if (res->fi->fib_prefsrc)
2440 fl4->saddr = res->fi->fib_prefsrc;
2441 else
2442 fl4->saddr = fl4->daddr;
2443 }
2444
2445 /* L3 master device is the loopback for that domain */
2446 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2447 net->loopback_dev;
2448 fl4->flowi4_oif = dev_out->ifindex;
2449 flags |= RTCF_LOCAL;
2450 goto make_route;
2451 }
2452
2453 fib_select_path(net, res, fl4, skb);
2454
2455 dev_out = FIB_RES_DEV(*res);
2456 fl4->flowi4_oif = dev_out->ifindex;
2457
2458
2459 make_route:
2460 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2461
2462 out:
2463 return rth;
2464 }
2465
2466 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2467 {
2468 return NULL;
2469 }
2470
2471 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2472 {
2473 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2474
2475 return mtu ? : dst->dev->mtu;
2476 }
2477
2478 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2479 struct sk_buff *skb, u32 mtu)
2480 {
2481 }
2482
2483 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2484 struct sk_buff *skb)
2485 {
2486 }
2487
2488 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2489 unsigned long old)
2490 {
2491 return NULL;
2492 }
2493
2494 static struct dst_ops ipv4_dst_blackhole_ops = {
2495 .family = AF_INET,
2496 .check = ipv4_blackhole_dst_check,
2497 .mtu = ipv4_blackhole_mtu,
2498 .default_advmss = ipv4_default_advmss,
2499 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2500 .redirect = ipv4_rt_blackhole_redirect,
2501 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2502 .neigh_lookup = ipv4_neigh_lookup,
2503 };
2504
2505 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2506 {
2507 struct rtable *ort = (struct rtable *) dst_orig;
2508 struct rtable *rt;
2509
2510 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2511 if (rt) {
2512 struct dst_entry *new = &rt->dst;
2513
2514 new->__use = 1;
2515 new->input = dst_discard;
2516 new->output = dst_discard_out;
2517
2518 new->dev = net->loopback_dev;
2519 if (new->dev)
2520 dev_hold(new->dev);
2521
2522 rt->rt_is_input = ort->rt_is_input;
2523 rt->rt_iif = ort->rt_iif;
2524 rt->rt_pmtu = ort->rt_pmtu;
2525
2526 rt->rt_genid = rt_genid_ipv4(net);
2527 rt->rt_flags = ort->rt_flags;
2528 rt->rt_type = ort->rt_type;
2529 rt->rt_gateway = ort->rt_gateway;
2530 rt->rt_uses_gateway = ort->rt_uses_gateway;
2531
2532 INIT_LIST_HEAD(&rt->rt_uncached);
2533 }
2534
2535 dst_release(dst_orig);
2536
2537 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2538 }
2539
2540 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2541 const struct sock *sk)
2542 {
2543 struct rtable *rt = __ip_route_output_key(net, flp4);
2544
2545 if (IS_ERR(rt))
2546 return rt;
2547
2548 if (flp4->flowi4_proto)
2549 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2550 flowi4_to_flowi(flp4),
2551 sk, 0);
2552
2553 return rt;
2554 }
2555 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2556
2557 /* called with rcu_read_lock held */
2558 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2559 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2560 u32 seq)
2561 {
2562 struct rtable *rt = skb_rtable(skb);
2563 struct rtmsg *r;
2564 struct nlmsghdr *nlh;
2565 unsigned long expires = 0;
2566 u32 error;
2567 u32 metrics[RTAX_MAX];
2568
2569 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2570 if (!nlh)
2571 return -EMSGSIZE;
2572
2573 r = nlmsg_data(nlh);
2574 r->rtm_family = AF_INET;
2575 r->rtm_dst_len = 32;
2576 r->rtm_src_len = 0;
2577 r->rtm_tos = fl4->flowi4_tos;
2578 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2579 if (nla_put_u32(skb, RTA_TABLE, table_id))
2580 goto nla_put_failure;
2581 r->rtm_type = rt->rt_type;
2582 r->rtm_scope = RT_SCOPE_UNIVERSE;
2583 r->rtm_protocol = RTPROT_UNSPEC;
2584 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2585 if (rt->rt_flags & RTCF_NOTIFY)
2586 r->rtm_flags |= RTM_F_NOTIFY;
2587 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2588 r->rtm_flags |= RTCF_DOREDIRECT;
2589
2590 if (nla_put_in_addr(skb, RTA_DST, dst))
2591 goto nla_put_failure;
2592 if (src) {
2593 r->rtm_src_len = 32;
2594 if (nla_put_in_addr(skb, RTA_SRC, src))
2595 goto nla_put_failure;
2596 }
2597 if (rt->dst.dev &&
2598 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2599 goto nla_put_failure;
2600 #ifdef CONFIG_IP_ROUTE_CLASSID
2601 if (rt->dst.tclassid &&
2602 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2603 goto nla_put_failure;
2604 #endif
2605 if (!rt_is_input_route(rt) &&
2606 fl4->saddr != src) {
2607 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2608 goto nla_put_failure;
2609 }
2610 if (rt->rt_uses_gateway &&
2611 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2612 goto nla_put_failure;
2613
2614 expires = rt->dst.expires;
2615 if (expires) {
2616 unsigned long now = jiffies;
2617
2618 if (time_before(now, expires))
2619 expires -= now;
2620 else
2621 expires = 0;
2622 }
2623
2624 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2625 if (rt->rt_pmtu && expires)
2626 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2627 if (rtnetlink_put_metrics(skb, metrics) < 0)
2628 goto nla_put_failure;
2629
2630 if (fl4->flowi4_mark &&
2631 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2632 goto nla_put_failure;
2633
2634 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2635 nla_put_u32(skb, RTA_UID,
2636 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2637 goto nla_put_failure;
2638
2639 error = rt->dst.error;
2640
2641 if (rt_is_input_route(rt)) {
2642 #ifdef CONFIG_IP_MROUTE
2643 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2644 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2645 int err = ipmr_get_route(net, skb,
2646 fl4->saddr, fl4->daddr,
2647 r, portid);
2648
2649 if (err <= 0) {
2650 if (err == 0)
2651 return 0;
2652 goto nla_put_failure;
2653 }
2654 } else
2655 #endif
2656 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2657 goto nla_put_failure;
2658 }
2659
2660 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2661 goto nla_put_failure;
2662
2663 nlmsg_end(skb, nlh);
2664 return 0;
2665
2666 nla_put_failure:
2667 nlmsg_cancel(skb, nlh);
2668 return -EMSGSIZE;
2669 }
2670
2671 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2672 struct netlink_ext_ack *extack)
2673 {
2674 struct net *net = sock_net(in_skb->sk);
2675 struct rtmsg *rtm;
2676 struct nlattr *tb[RTA_MAX+1];
2677 struct fib_result res = {};
2678 struct rtable *rt = NULL;
2679 struct flowi4 fl4;
2680 __be32 dst = 0;
2681 __be32 src = 0;
2682 u32 iif;
2683 int err;
2684 int mark;
2685 struct sk_buff *skb;
2686 u32 table_id = RT_TABLE_MAIN;
2687 kuid_t uid;
2688
2689 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2690 extack);
2691 if (err < 0)
2692 goto errout;
2693
2694 rtm = nlmsg_data(nlh);
2695
2696 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2697 if (!skb) {
2698 err = -ENOBUFS;
2699 goto errout;
2700 }
2701
2702 /* Reserve room for dummy headers, this skb can pass
2703 through good chunk of routing engine.
2704 */
2705 skb_reset_mac_header(skb);
2706 skb_reset_network_header(skb);
2707
2708 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2709 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2710 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2711 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2712 if (tb[RTA_UID])
2713 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2714 else
2715 uid = (iif ? INVALID_UID : current_uid());
2716
2717 /* Bugfix: need to give ip_route_input enough of an IP header to
2718 * not gag.
2719 */
2720 ip_hdr(skb)->protocol = IPPROTO_UDP;
2721 ip_hdr(skb)->saddr = src;
2722 ip_hdr(skb)->daddr = dst;
2723
2724 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2725
2726 memset(&fl4, 0, sizeof(fl4));
2727 fl4.daddr = dst;
2728 fl4.saddr = src;
2729 fl4.flowi4_tos = rtm->rtm_tos;
2730 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2731 fl4.flowi4_mark = mark;
2732 fl4.flowi4_uid = uid;
2733
2734 rcu_read_lock();
2735
2736 if (iif) {
2737 struct net_device *dev;
2738
2739 dev = dev_get_by_index_rcu(net, iif);
2740 if (!dev) {
2741 err = -ENODEV;
2742 goto errout_free;
2743 }
2744
2745 skb->protocol = htons(ETH_P_IP);
2746 skb->dev = dev;
2747 skb->mark = mark;
2748 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
2749 dev, &res);
2750
2751 rt = skb_rtable(skb);
2752 if (err == 0 && rt->dst.error)
2753 err = -rt->dst.error;
2754 } else {
2755 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
2756 err = 0;
2757 if (IS_ERR(rt))
2758 err = PTR_ERR(rt);
2759 else
2760 skb_dst_set(skb, &rt->dst);
2761 }
2762
2763 if (err)
2764 goto errout_free;
2765
2766 if (rtm->rtm_flags & RTM_F_NOTIFY)
2767 rt->rt_flags |= RTCF_NOTIFY;
2768
2769 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2770 table_id = rt->rt_table_id;
2771
2772 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2773 if (!res.fi) {
2774 err = fib_props[res.type].error;
2775 if (!err)
2776 err = -EHOSTUNREACH;
2777 goto errout_free;
2778 }
2779 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
2780 nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
2781 rt->rt_type, res.prefix, res.prefixlen,
2782 fl4.flowi4_tos, res.fi, 0);
2783 } else {
2784 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2785 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
2786 }
2787 if (err < 0)
2788 goto errout_free;
2789
2790 rcu_read_unlock();
2791
2792 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2793 errout:
2794 return err;
2795
2796 errout_free:
2797 rcu_read_unlock();
2798 kfree_skb(skb);
2799 goto errout;
2800 }
2801
2802 void ip_rt_multicast_event(struct in_device *in_dev)
2803 {
2804 rt_cache_flush(dev_net(in_dev->dev));
2805 }
2806
2807 #ifdef CONFIG_SYSCTL
2808 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2809 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2810 static int ip_rt_gc_elasticity __read_mostly = 8;
2811
2812 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2813 void __user *buffer,
2814 size_t *lenp, loff_t *ppos)
2815 {
2816 struct net *net = (struct net *)__ctl->extra1;
2817
2818 if (write) {
2819 rt_cache_flush(net);
2820 fnhe_genid_bump(net);
2821 return 0;
2822 }
2823
2824 return -EINVAL;
2825 }
2826
2827 static struct ctl_table ipv4_route_table[] = {
2828 {
2829 .procname = "gc_thresh",
2830 .data = &ipv4_dst_ops.gc_thresh,
2831 .maxlen = sizeof(int),
2832 .mode = 0644,
2833 .proc_handler = proc_dointvec,
2834 },
2835 {
2836 .procname = "max_size",
2837 .data = &ip_rt_max_size,
2838 .maxlen = sizeof(int),
2839 .mode = 0644,
2840 .proc_handler = proc_dointvec,
2841 },
2842 {
2843 /* Deprecated. Use gc_min_interval_ms */
2844
2845 .procname = "gc_min_interval",
2846 .data = &ip_rt_gc_min_interval,
2847 .maxlen = sizeof(int),
2848 .mode = 0644,
2849 .proc_handler = proc_dointvec_jiffies,
2850 },
2851 {
2852 .procname = "gc_min_interval_ms",
2853 .data = &ip_rt_gc_min_interval,
2854 .maxlen = sizeof(int),
2855 .mode = 0644,
2856 .proc_handler = proc_dointvec_ms_jiffies,
2857 },
2858 {
2859 .procname = "gc_timeout",
2860 .data = &ip_rt_gc_timeout,
2861 .maxlen = sizeof(int),
2862 .mode = 0644,
2863 .proc_handler = proc_dointvec_jiffies,
2864 },
2865 {
2866 .procname = "gc_interval",
2867 .data = &ip_rt_gc_interval,
2868 .maxlen = sizeof(int),
2869 .mode = 0644,
2870 .proc_handler = proc_dointvec_jiffies,
2871 },
2872 {
2873 .procname = "redirect_load",
2874 .data = &ip_rt_redirect_load,
2875 .maxlen = sizeof(int),
2876 .mode = 0644,
2877 .proc_handler = proc_dointvec,
2878 },
2879 {
2880 .procname = "redirect_number",
2881 .data = &ip_rt_redirect_number,
2882 .maxlen = sizeof(int),
2883 .mode = 0644,
2884 .proc_handler = proc_dointvec,
2885 },
2886 {
2887 .procname = "redirect_silence",
2888 .data = &ip_rt_redirect_silence,
2889 .maxlen = sizeof(int),
2890 .mode = 0644,
2891 .proc_handler = proc_dointvec,
2892 },
2893 {
2894 .procname = "error_cost",
2895 .data = &ip_rt_error_cost,
2896 .maxlen = sizeof(int),
2897 .mode = 0644,
2898 .proc_handler = proc_dointvec,
2899 },
2900 {
2901 .procname = "error_burst",
2902 .data = &ip_rt_error_burst,
2903 .maxlen = sizeof(int),
2904 .mode = 0644,
2905 .proc_handler = proc_dointvec,
2906 },
2907 {
2908 .procname = "gc_elasticity",
2909 .data = &ip_rt_gc_elasticity,
2910 .maxlen = sizeof(int),
2911 .mode = 0644,
2912 .proc_handler = proc_dointvec,
2913 },
2914 {
2915 .procname = "mtu_expires",
2916 .data = &ip_rt_mtu_expires,
2917 .maxlen = sizeof(int),
2918 .mode = 0644,
2919 .proc_handler = proc_dointvec_jiffies,
2920 },
2921 {
2922 .procname = "min_pmtu",
2923 .data = &ip_rt_min_pmtu,
2924 .maxlen = sizeof(int),
2925 .mode = 0644,
2926 .proc_handler = proc_dointvec,
2927 },
2928 {
2929 .procname = "min_adv_mss",
2930 .data = &ip_rt_min_advmss,
2931 .maxlen = sizeof(int),
2932 .mode = 0644,
2933 .proc_handler = proc_dointvec,
2934 },
2935 { }
2936 };
2937
2938 static struct ctl_table ipv4_route_flush_table[] = {
2939 {
2940 .procname = "flush",
2941 .maxlen = sizeof(int),
2942 .mode = 0200,
2943 .proc_handler = ipv4_sysctl_rtcache_flush,
2944 },
2945 { },
2946 };
2947
2948 static __net_init int sysctl_route_net_init(struct net *net)
2949 {
2950 struct ctl_table *tbl;
2951
2952 tbl = ipv4_route_flush_table;
2953 if (!net_eq(net, &init_net)) {
2954 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2955 if (!tbl)
2956 goto err_dup;
2957
2958 /* Don't export sysctls to unprivileged users */
2959 if (net->user_ns != &init_user_ns)
2960 tbl[0].procname = NULL;
2961 }
2962 tbl[0].extra1 = net;
2963
2964 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2965 if (!net->ipv4.route_hdr)
2966 goto err_reg;
2967 return 0;
2968
2969 err_reg:
2970 if (tbl != ipv4_route_flush_table)
2971 kfree(tbl);
2972 err_dup:
2973 return -ENOMEM;
2974 }
2975
2976 static __net_exit void sysctl_route_net_exit(struct net *net)
2977 {
2978 struct ctl_table *tbl;
2979
2980 tbl = net->ipv4.route_hdr->ctl_table_arg;
2981 unregister_net_sysctl_table(net->ipv4.route_hdr);
2982 BUG_ON(tbl == ipv4_route_flush_table);
2983 kfree(tbl);
2984 }
2985
2986 static __net_initdata struct pernet_operations sysctl_route_ops = {
2987 .init = sysctl_route_net_init,
2988 .exit = sysctl_route_net_exit,
2989 };
2990 #endif
2991
2992 static __net_init int rt_genid_init(struct net *net)
2993 {
2994 atomic_set(&net->ipv4.rt_genid, 0);
2995 atomic_set(&net->fnhe_genid, 0);
2996 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
2997 return 0;
2998 }
2999
3000 static __net_initdata struct pernet_operations rt_genid_ops = {
3001 .init = rt_genid_init,
3002 };
3003
3004 static int __net_init ipv4_inetpeer_init(struct net *net)
3005 {
3006 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3007
3008 if (!bp)
3009 return -ENOMEM;
3010 inet_peer_base_init(bp);
3011 net->ipv4.peers = bp;
3012 return 0;
3013 }
3014
3015 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3016 {
3017 struct inet_peer_base *bp = net->ipv4.peers;
3018
3019 net->ipv4.peers = NULL;
3020 inetpeer_invalidate_tree(bp);
3021 kfree(bp);
3022 }
3023
3024 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3025 .init = ipv4_inetpeer_init,
3026 .exit = ipv4_inetpeer_exit,
3027 };
3028
3029 #ifdef CONFIG_IP_ROUTE_CLASSID
3030 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3031 #endif /* CONFIG_IP_ROUTE_CLASSID */
3032
3033 int __init ip_rt_init(void)
3034 {
3035 int rc = 0;
3036 int cpu;
3037
3038 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
3039 if (!ip_idents)
3040 panic("IP: failed to allocate ip_idents\n");
3041
3042 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3043
3044 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3045 if (!ip_tstamps)
3046 panic("IP: failed to allocate ip_tstamps\n");
3047
3048 for_each_possible_cpu(cpu) {
3049 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3050
3051 INIT_LIST_HEAD(&ul->head);
3052 spin_lock_init(&ul->lock);
3053 }
3054 #ifdef CONFIG_IP_ROUTE_CLASSID
3055 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3056 if (!ip_rt_acct)
3057 panic("IP: failed to allocate ip_rt_acct\n");
3058 #endif
3059
3060 ipv4_dst_ops.kmem_cachep =
3061 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3062 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3063
3064 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3065
3066 if (dst_entries_init(&ipv4_dst_ops) < 0)
3067 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3068
3069 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3070 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3071
3072 ipv4_dst_ops.gc_thresh = ~0;
3073 ip_rt_max_size = INT_MAX;
3074
3075 devinet_init();
3076 ip_fib_init();
3077
3078 if (ip_rt_proc_init())
3079 pr_err("Unable to create route proc files\n");
3080 #ifdef CONFIG_XFRM
3081 xfrm_init();
3082 xfrm4_init();
3083 #endif
3084 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3085
3086 #ifdef CONFIG_SYSCTL
3087 register_pernet_subsys(&sysctl_route_ops);
3088 #endif
3089 register_pernet_subsys(&rt_genid_ops);
3090 register_pernet_subsys(&ipv4_inetpeer_ops);
3091 return rc;
3092 }
3093
3094 #ifdef CONFIG_SYSCTL
3095 /*
3096 * We really need to sanitize the damn ipv4 init order, then all
3097 * this nonsense will go away.
3098 */
3099 void __init ip_static_sysctl_init(void)
3100 {
3101 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3102 }
3103 #endif
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