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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 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 void rt_del_uncached_list(struct rtable *rt)
1397 {
1398 if (!list_empty(&rt->rt_uncached)) {
1399 struct uncached_list *ul = rt->rt_uncached_list;
1400
1401 spin_lock_bh(&ul->lock);
1402 list_del(&rt->rt_uncached);
1403 spin_unlock_bh(&ul->lock);
1404 }
1405 }
1406
1407 static void ipv4_dst_destroy(struct dst_entry *dst)
1408 {
1409 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1410 struct rtable *rt = (struct rtable *)dst;
1411
1412 if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
1413 kfree(p);
1414
1415 rt_del_uncached_list(rt);
1416 }
1417
1418 void rt_flush_dev(struct net_device *dev)
1419 {
1420 struct net *net = dev_net(dev);
1421 struct rtable *rt;
1422 int cpu;
1423
1424 for_each_possible_cpu(cpu) {
1425 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1426
1427 spin_lock_bh(&ul->lock);
1428 list_for_each_entry(rt, &ul->head, rt_uncached) {
1429 if (rt->dst.dev != dev)
1430 continue;
1431 rt->dst.dev = net->loopback_dev;
1432 dev_hold(rt->dst.dev);
1433 dev_put(dev);
1434 }
1435 spin_unlock_bh(&ul->lock);
1436 }
1437 }
1438
1439 static bool rt_cache_valid(const struct rtable *rt)
1440 {
1441 return rt &&
1442 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1443 !rt_is_expired(rt);
1444 }
1445
1446 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1447 const struct fib_result *res,
1448 struct fib_nh_exception *fnhe,
1449 struct fib_info *fi, u16 type, u32 itag,
1450 const bool do_cache)
1451 {
1452 bool cached = false;
1453
1454 if (fi) {
1455 struct fib_nh *nh = &FIB_RES_NH(*res);
1456
1457 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1458 rt->rt_gateway = nh->nh_gw;
1459 rt->rt_uses_gateway = 1;
1460 }
1461 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1462 if (fi->fib_metrics != &dst_default_metrics) {
1463 rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1464 refcount_inc(&fi->fib_metrics->refcnt);
1465 }
1466 #ifdef CONFIG_IP_ROUTE_CLASSID
1467 rt->dst.tclassid = nh->nh_tclassid;
1468 #endif
1469 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1470 if (unlikely(fnhe))
1471 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1472 else if (do_cache)
1473 cached = rt_cache_route(nh, rt);
1474 if (unlikely(!cached)) {
1475 /* Routes we intend to cache in nexthop exception or
1476 * FIB nexthop have the DST_NOCACHE bit clear.
1477 * However, if we are unsuccessful at storing this
1478 * route into the cache we really need to set it.
1479 */
1480 if (!rt->rt_gateway)
1481 rt->rt_gateway = daddr;
1482 rt_add_uncached_list(rt);
1483 }
1484 } else
1485 rt_add_uncached_list(rt);
1486
1487 #ifdef CONFIG_IP_ROUTE_CLASSID
1488 #ifdef CONFIG_IP_MULTIPLE_TABLES
1489 set_class_tag(rt, res->tclassid);
1490 #endif
1491 set_class_tag(rt, itag);
1492 #endif
1493 }
1494
1495 struct rtable *rt_dst_alloc(struct net_device *dev,
1496 unsigned int flags, u16 type,
1497 bool nopolicy, bool noxfrm, bool will_cache)
1498 {
1499 struct rtable *rt;
1500
1501 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1502 (will_cache ? 0 : DST_HOST) |
1503 (nopolicy ? DST_NOPOLICY : 0) |
1504 (noxfrm ? DST_NOXFRM : 0));
1505
1506 if (rt) {
1507 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1508 rt->rt_flags = flags;
1509 rt->rt_type = type;
1510 rt->rt_is_input = 0;
1511 rt->rt_iif = 0;
1512 rt->rt_pmtu = 0;
1513 rt->rt_gateway = 0;
1514 rt->rt_uses_gateway = 0;
1515 rt->rt_table_id = 0;
1516 INIT_LIST_HEAD(&rt->rt_uncached);
1517
1518 rt->dst.output = ip_output;
1519 if (flags & RTCF_LOCAL)
1520 rt->dst.input = ip_local_deliver;
1521 }
1522
1523 return rt;
1524 }
1525 EXPORT_SYMBOL(rt_dst_alloc);
1526
1527 /* called in rcu_read_lock() section */
1528 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1529 u8 tos, struct net_device *dev,
1530 struct in_device *in_dev, u32 *itag)
1531 {
1532 int err;
1533
1534 /* Primary sanity checks. */
1535 if (!in_dev)
1536 return -EINVAL;
1537
1538 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1539 skb->protocol != htons(ETH_P_IP))
1540 return -EINVAL;
1541
1542 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1543 return -EINVAL;
1544
1545 if (ipv4_is_zeronet(saddr)) {
1546 if (!ipv4_is_local_multicast(daddr))
1547 return -EINVAL;
1548 } else {
1549 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1550 in_dev, itag);
1551 if (err < 0)
1552 return err;
1553 }
1554 return 0;
1555 }
1556
1557 /* called in rcu_read_lock() section */
1558 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1559 u8 tos, struct net_device *dev, int our)
1560 {
1561 struct in_device *in_dev = __in_dev_get_rcu(dev);
1562 unsigned int flags = RTCF_MULTICAST;
1563 struct rtable *rth;
1564 u32 itag = 0;
1565 int err;
1566
1567 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1568 if (err)
1569 return err;
1570
1571 if (our)
1572 flags |= RTCF_LOCAL;
1573
1574 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1575 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1576 if (!rth)
1577 return -ENOBUFS;
1578
1579 #ifdef CONFIG_IP_ROUTE_CLASSID
1580 rth->dst.tclassid = itag;
1581 #endif
1582 rth->dst.output = ip_rt_bug;
1583 rth->rt_is_input= 1;
1584
1585 #ifdef CONFIG_IP_MROUTE
1586 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1587 rth->dst.input = ip_mr_input;
1588 #endif
1589 RT_CACHE_STAT_INC(in_slow_mc);
1590
1591 skb_dst_set(skb, &rth->dst);
1592 return 0;
1593 }
1594
1595
1596 static void ip_handle_martian_source(struct net_device *dev,
1597 struct in_device *in_dev,
1598 struct sk_buff *skb,
1599 __be32 daddr,
1600 __be32 saddr)
1601 {
1602 RT_CACHE_STAT_INC(in_martian_src);
1603 #ifdef CONFIG_IP_ROUTE_VERBOSE
1604 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1605 /*
1606 * RFC1812 recommendation, if source is martian,
1607 * the only hint is MAC header.
1608 */
1609 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1610 &daddr, &saddr, dev->name);
1611 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1612 print_hex_dump(KERN_WARNING, "ll header: ",
1613 DUMP_PREFIX_OFFSET, 16, 1,
1614 skb_mac_header(skb),
1615 dev->hard_header_len, true);
1616 }
1617 }
1618 #endif
1619 }
1620
1621 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1622 {
1623 struct fnhe_hash_bucket *hash;
1624 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1625 u32 hval = fnhe_hashfun(daddr);
1626
1627 spin_lock_bh(&fnhe_lock);
1628
1629 hash = rcu_dereference_protected(nh->nh_exceptions,
1630 lockdep_is_held(&fnhe_lock));
1631 hash += hval;
1632
1633 fnhe_p = &hash->chain;
1634 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1635 while (fnhe) {
1636 if (fnhe->fnhe_daddr == daddr) {
1637 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1638 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1639 fnhe_flush_routes(fnhe);
1640 kfree_rcu(fnhe, rcu);
1641 break;
1642 }
1643 fnhe_p = &fnhe->fnhe_next;
1644 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1645 lockdep_is_held(&fnhe_lock));
1646 }
1647
1648 spin_unlock_bh(&fnhe_lock);
1649 }
1650
1651 static void set_lwt_redirect(struct rtable *rth)
1652 {
1653 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1654 rth->dst.lwtstate->orig_output = rth->dst.output;
1655 rth->dst.output = lwtunnel_output;
1656 }
1657
1658 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1659 rth->dst.lwtstate->orig_input = rth->dst.input;
1660 rth->dst.input = lwtunnel_input;
1661 }
1662 }
1663
1664 /* called in rcu_read_lock() section */
1665 static int __mkroute_input(struct sk_buff *skb,
1666 const struct fib_result *res,
1667 struct in_device *in_dev,
1668 __be32 daddr, __be32 saddr, u32 tos)
1669 {
1670 struct fib_nh_exception *fnhe;
1671 struct rtable *rth;
1672 int err;
1673 struct in_device *out_dev;
1674 bool do_cache;
1675 u32 itag = 0;
1676
1677 /* get a working reference to the output device */
1678 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1679 if (!out_dev) {
1680 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1681 return -EINVAL;
1682 }
1683
1684 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1685 in_dev->dev, in_dev, &itag);
1686 if (err < 0) {
1687 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1688 saddr);
1689
1690 goto cleanup;
1691 }
1692
1693 do_cache = res->fi && !itag;
1694 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1695 skb->protocol == htons(ETH_P_IP) &&
1696 (IN_DEV_SHARED_MEDIA(out_dev) ||
1697 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1698 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1699
1700 if (skb->protocol != htons(ETH_P_IP)) {
1701 /* Not IP (i.e. ARP). Do not create route, if it is
1702 * invalid for proxy arp. DNAT routes are always valid.
1703 *
1704 * Proxy arp feature have been extended to allow, ARP
1705 * replies back to the same interface, to support
1706 * Private VLAN switch technologies. See arp.c.
1707 */
1708 if (out_dev == in_dev &&
1709 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1710 err = -EINVAL;
1711 goto cleanup;
1712 }
1713 }
1714
1715 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1716 if (do_cache) {
1717 if (fnhe) {
1718 rth = rcu_dereference(fnhe->fnhe_rth_input);
1719 if (rth && rth->dst.expires &&
1720 time_after(jiffies, rth->dst.expires)) {
1721 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1722 fnhe = NULL;
1723 } else {
1724 goto rt_cache;
1725 }
1726 }
1727
1728 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1729
1730 rt_cache:
1731 if (rt_cache_valid(rth)) {
1732 skb_dst_set_noref(skb, &rth->dst);
1733 goto out;
1734 }
1735 }
1736
1737 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1738 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1739 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1740 if (!rth) {
1741 err = -ENOBUFS;
1742 goto cleanup;
1743 }
1744
1745 rth->rt_is_input = 1;
1746 if (res->table)
1747 rth->rt_table_id = res->table->tb_id;
1748 RT_CACHE_STAT_INC(in_slow_tot);
1749
1750 rth->dst.input = ip_forward;
1751
1752 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1753 do_cache);
1754 set_lwt_redirect(rth);
1755 skb_dst_set(skb, &rth->dst);
1756 out:
1757 err = 0;
1758 cleanup:
1759 return err;
1760 }
1761
1762 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1763 /* To make ICMP packets follow the right flow, the multipath hash is
1764 * calculated from the inner IP addresses.
1765 */
1766 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1767 struct flow_keys *hash_keys)
1768 {
1769 const struct iphdr *outer_iph = ip_hdr(skb);
1770 const struct iphdr *inner_iph;
1771 const struct icmphdr *icmph;
1772 struct iphdr _inner_iph;
1773 struct icmphdr _icmph;
1774
1775 hash_keys->addrs.v4addrs.src = outer_iph->saddr;
1776 hash_keys->addrs.v4addrs.dst = outer_iph->daddr;
1777 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1778 return;
1779
1780 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1781 return;
1782
1783 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1784 &_icmph);
1785 if (!icmph)
1786 return;
1787
1788 if (icmph->type != ICMP_DEST_UNREACH &&
1789 icmph->type != ICMP_REDIRECT &&
1790 icmph->type != ICMP_TIME_EXCEEDED &&
1791 icmph->type != ICMP_PARAMETERPROB)
1792 return;
1793
1794 inner_iph = skb_header_pointer(skb,
1795 outer_iph->ihl * 4 + sizeof(_icmph),
1796 sizeof(_inner_iph), &_inner_iph);
1797 if (!inner_iph)
1798 return;
1799 hash_keys->addrs.v4addrs.src = inner_iph->saddr;
1800 hash_keys->addrs.v4addrs.dst = inner_iph->daddr;
1801 }
1802
1803 /* if skb is set it will be used and fl4 can be NULL */
1804 int fib_multipath_hash(const struct fib_info *fi, const struct flowi4 *fl4,
1805 const struct sk_buff *skb)
1806 {
1807 struct net *net = fi->fib_net;
1808 struct flow_keys hash_keys;
1809 u32 mhash;
1810
1811 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1812 case 0:
1813 memset(&hash_keys, 0, sizeof(hash_keys));
1814 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1815 if (skb) {
1816 ip_multipath_l3_keys(skb, &hash_keys);
1817 } else {
1818 hash_keys.addrs.v4addrs.src = fl4->saddr;
1819 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1820 }
1821 break;
1822 case 1:
1823 /* skb is currently provided only when forwarding */
1824 if (skb) {
1825 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1826 struct flow_keys keys;
1827
1828 /* short-circuit if we already have L4 hash present */
1829 if (skb->l4_hash)
1830 return skb_get_hash_raw(skb) >> 1;
1831 memset(&hash_keys, 0, sizeof(hash_keys));
1832 skb_flow_dissect_flow_keys(skb, &keys, flag);
1833 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1834 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1835 hash_keys.ports.src = keys.ports.src;
1836 hash_keys.ports.dst = keys.ports.dst;
1837 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1838 } else {
1839 memset(&hash_keys, 0, sizeof(hash_keys));
1840 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1841 hash_keys.addrs.v4addrs.src = fl4->saddr;
1842 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1843 hash_keys.ports.src = fl4->fl4_sport;
1844 hash_keys.ports.dst = fl4->fl4_dport;
1845 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1846 }
1847 break;
1848 }
1849 mhash = flow_hash_from_keys(&hash_keys);
1850
1851 return mhash >> 1;
1852 }
1853 EXPORT_SYMBOL_GPL(fib_multipath_hash);
1854 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1855
1856 static int ip_mkroute_input(struct sk_buff *skb,
1857 struct fib_result *res,
1858 struct in_device *in_dev,
1859 __be32 daddr, __be32 saddr, u32 tos)
1860 {
1861 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1862 if (res->fi && res->fi->fib_nhs > 1) {
1863 int h = fib_multipath_hash(res->fi, NULL, skb);
1864
1865 fib_select_multipath(res, h);
1866 }
1867 #endif
1868
1869 /* create a routing cache entry */
1870 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1871 }
1872
1873 /*
1874 * NOTE. We drop all the packets that has local source
1875 * addresses, because every properly looped back packet
1876 * must have correct destination already attached by output routine.
1877 *
1878 * Such approach solves two big problems:
1879 * 1. Not simplex devices are handled properly.
1880 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1881 * called with rcu_read_lock()
1882 */
1883
1884 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1885 u8 tos, struct net_device *dev,
1886 struct fib_result *res)
1887 {
1888 struct in_device *in_dev = __in_dev_get_rcu(dev);
1889 struct ip_tunnel_info *tun_info;
1890 struct flowi4 fl4;
1891 unsigned int flags = 0;
1892 u32 itag = 0;
1893 struct rtable *rth;
1894 int err = -EINVAL;
1895 struct net *net = dev_net(dev);
1896 bool do_cache;
1897
1898 /* IP on this device is disabled. */
1899
1900 if (!in_dev)
1901 goto out;
1902
1903 /* Check for the most weird martians, which can be not detected
1904 by fib_lookup.
1905 */
1906
1907 tun_info = skb_tunnel_info(skb);
1908 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1909 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1910 else
1911 fl4.flowi4_tun_key.tun_id = 0;
1912 skb_dst_drop(skb);
1913
1914 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1915 goto martian_source;
1916
1917 res->fi = NULL;
1918 res->table = NULL;
1919 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1920 goto brd_input;
1921
1922 /* Accept zero addresses only to limited broadcast;
1923 * I even do not know to fix it or not. Waiting for complains :-)
1924 */
1925 if (ipv4_is_zeronet(saddr))
1926 goto martian_source;
1927
1928 if (ipv4_is_zeronet(daddr))
1929 goto martian_destination;
1930
1931 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1932 * and call it once if daddr or/and saddr are loopback addresses
1933 */
1934 if (ipv4_is_loopback(daddr)) {
1935 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1936 goto martian_destination;
1937 } else if (ipv4_is_loopback(saddr)) {
1938 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1939 goto martian_source;
1940 }
1941
1942 /*
1943 * Now we are ready to route packet.
1944 */
1945 fl4.flowi4_oif = 0;
1946 fl4.flowi4_iif = dev->ifindex;
1947 fl4.flowi4_mark = skb->mark;
1948 fl4.flowi4_tos = tos;
1949 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1950 fl4.flowi4_flags = 0;
1951 fl4.daddr = daddr;
1952 fl4.saddr = saddr;
1953 fl4.flowi4_uid = sock_net_uid(net, NULL);
1954 err = fib_lookup(net, &fl4, res, 0);
1955 if (err != 0) {
1956 if (!IN_DEV_FORWARD(in_dev))
1957 err = -EHOSTUNREACH;
1958 goto no_route;
1959 }
1960
1961 if (res->type == RTN_BROADCAST)
1962 goto brd_input;
1963
1964 if (res->type == RTN_LOCAL) {
1965 err = fib_validate_source(skb, saddr, daddr, tos,
1966 0, dev, in_dev, &itag);
1967 if (err < 0)
1968 goto martian_source;
1969 goto local_input;
1970 }
1971
1972 if (!IN_DEV_FORWARD(in_dev)) {
1973 err = -EHOSTUNREACH;
1974 goto no_route;
1975 }
1976 if (res->type != RTN_UNICAST)
1977 goto martian_destination;
1978
1979 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1980 out: return err;
1981
1982 brd_input:
1983 if (skb->protocol != htons(ETH_P_IP))
1984 goto e_inval;
1985
1986 if (!ipv4_is_zeronet(saddr)) {
1987 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1988 in_dev, &itag);
1989 if (err < 0)
1990 goto martian_source;
1991 }
1992 flags |= RTCF_BROADCAST;
1993 res->type = RTN_BROADCAST;
1994 RT_CACHE_STAT_INC(in_brd);
1995
1996 local_input:
1997 do_cache = false;
1998 if (res->fi) {
1999 if (!itag) {
2000 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
2001 if (rt_cache_valid(rth)) {
2002 skb_dst_set_noref(skb, &rth->dst);
2003 err = 0;
2004 goto out;
2005 }
2006 do_cache = true;
2007 }
2008 }
2009
2010 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2011 flags | RTCF_LOCAL, res->type,
2012 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2013 if (!rth)
2014 goto e_nobufs;
2015
2016 rth->dst.output= ip_rt_bug;
2017 #ifdef CONFIG_IP_ROUTE_CLASSID
2018 rth->dst.tclassid = itag;
2019 #endif
2020 rth->rt_is_input = 1;
2021 if (res->table)
2022 rth->rt_table_id = res->table->tb_id;
2023
2024 RT_CACHE_STAT_INC(in_slow_tot);
2025 if (res->type == RTN_UNREACHABLE) {
2026 rth->dst.input= ip_error;
2027 rth->dst.error= -err;
2028 rth->rt_flags &= ~RTCF_LOCAL;
2029 }
2030
2031 if (do_cache) {
2032 struct fib_nh *nh = &FIB_RES_NH(*res);
2033
2034 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2035 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2036 WARN_ON(rth->dst.input == lwtunnel_input);
2037 rth->dst.lwtstate->orig_input = rth->dst.input;
2038 rth->dst.input = lwtunnel_input;
2039 }
2040
2041 if (unlikely(!rt_cache_route(nh, rth)))
2042 rt_add_uncached_list(rth);
2043 }
2044 skb_dst_set(skb, &rth->dst);
2045 err = 0;
2046 goto out;
2047
2048 no_route:
2049 RT_CACHE_STAT_INC(in_no_route);
2050 res->type = RTN_UNREACHABLE;
2051 res->fi = NULL;
2052 res->table = NULL;
2053 goto local_input;
2054
2055 /*
2056 * Do not cache martian addresses: they should be logged (RFC1812)
2057 */
2058 martian_destination:
2059 RT_CACHE_STAT_INC(in_martian_dst);
2060 #ifdef CONFIG_IP_ROUTE_VERBOSE
2061 if (IN_DEV_LOG_MARTIANS(in_dev))
2062 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2063 &daddr, &saddr, dev->name);
2064 #endif
2065
2066 e_inval:
2067 err = -EINVAL;
2068 goto out;
2069
2070 e_nobufs:
2071 err = -ENOBUFS;
2072 goto out;
2073
2074 martian_source:
2075 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2076 goto out;
2077 }
2078
2079 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2080 u8 tos, struct net_device *dev)
2081 {
2082 struct fib_result res;
2083 int err;
2084
2085 tos &= IPTOS_RT_MASK;
2086 rcu_read_lock();
2087 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2088 rcu_read_unlock();
2089
2090 return err;
2091 }
2092 EXPORT_SYMBOL(ip_route_input_noref);
2093
2094 /* called with rcu_read_lock held */
2095 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2096 u8 tos, struct net_device *dev, struct fib_result *res)
2097 {
2098 /* Multicast recognition logic is moved from route cache to here.
2099 The problem was that too many Ethernet cards have broken/missing
2100 hardware multicast filters :-( As result the host on multicasting
2101 network acquires a lot of useless route cache entries, sort of
2102 SDR messages from all the world. Now we try to get rid of them.
2103 Really, provided software IP multicast filter is organized
2104 reasonably (at least, hashed), it does not result in a slowdown
2105 comparing with route cache reject entries.
2106 Note, that multicast routers are not affected, because
2107 route cache entry is created eventually.
2108 */
2109 if (ipv4_is_multicast(daddr)) {
2110 struct in_device *in_dev = __in_dev_get_rcu(dev);
2111 int our = 0;
2112 int err = -EINVAL;
2113
2114 if (in_dev)
2115 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2116 ip_hdr(skb)->protocol);
2117
2118 /* check l3 master if no match yet */
2119 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2120 struct in_device *l3_in_dev;
2121
2122 l3_in_dev = __in_dev_get_rcu(skb->dev);
2123 if (l3_in_dev)
2124 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2125 ip_hdr(skb)->protocol);
2126 }
2127
2128 if (our
2129 #ifdef CONFIG_IP_MROUTE
2130 ||
2131 (!ipv4_is_local_multicast(daddr) &&
2132 IN_DEV_MFORWARD(in_dev))
2133 #endif
2134 ) {
2135 err = ip_route_input_mc(skb, daddr, saddr,
2136 tos, dev, our);
2137 }
2138 return err;
2139 }
2140
2141 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2142 }
2143
2144 /* called with rcu_read_lock() */
2145 static struct rtable *__mkroute_output(const struct fib_result *res,
2146 const struct flowi4 *fl4, int orig_oif,
2147 struct net_device *dev_out,
2148 unsigned int flags)
2149 {
2150 struct fib_info *fi = res->fi;
2151 struct fib_nh_exception *fnhe;
2152 struct in_device *in_dev;
2153 u16 type = res->type;
2154 struct rtable *rth;
2155 bool do_cache;
2156
2157 in_dev = __in_dev_get_rcu(dev_out);
2158 if (!in_dev)
2159 return ERR_PTR(-EINVAL);
2160
2161 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2162 if (ipv4_is_loopback(fl4->saddr) &&
2163 !(dev_out->flags & IFF_LOOPBACK) &&
2164 !netif_is_l3_master(dev_out))
2165 return ERR_PTR(-EINVAL);
2166
2167 if (ipv4_is_lbcast(fl4->daddr))
2168 type = RTN_BROADCAST;
2169 else if (ipv4_is_multicast(fl4->daddr))
2170 type = RTN_MULTICAST;
2171 else if (ipv4_is_zeronet(fl4->daddr))
2172 return ERR_PTR(-EINVAL);
2173
2174 if (dev_out->flags & IFF_LOOPBACK)
2175 flags |= RTCF_LOCAL;
2176
2177 do_cache = true;
2178 if (type == RTN_BROADCAST) {
2179 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2180 fi = NULL;
2181 } else if (type == RTN_MULTICAST) {
2182 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2183 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2184 fl4->flowi4_proto))
2185 flags &= ~RTCF_LOCAL;
2186 else
2187 do_cache = false;
2188 /* If multicast route do not exist use
2189 * default one, but do not gateway in this case.
2190 * Yes, it is hack.
2191 */
2192 if (fi && res->prefixlen < 4)
2193 fi = NULL;
2194 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2195 (orig_oif != dev_out->ifindex)) {
2196 /* For local routes that require a particular output interface
2197 * we do not want to cache the result. Caching the result
2198 * causes incorrect behaviour when there are multiple source
2199 * addresses on the interface, the end result being that if the
2200 * intended recipient is waiting on that interface for the
2201 * packet he won't receive it because it will be delivered on
2202 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2203 * be set to the loopback interface as well.
2204 */
2205 fi = NULL;
2206 }
2207
2208 fnhe = NULL;
2209 do_cache &= fi != NULL;
2210 if (do_cache) {
2211 struct rtable __rcu **prth;
2212 struct fib_nh *nh = &FIB_RES_NH(*res);
2213
2214 fnhe = find_exception(nh, fl4->daddr);
2215 if (fnhe) {
2216 prth = &fnhe->fnhe_rth_output;
2217 rth = rcu_dereference(*prth);
2218 if (rth && rth->dst.expires &&
2219 time_after(jiffies, rth->dst.expires)) {
2220 ip_del_fnhe(nh, fl4->daddr);
2221 fnhe = NULL;
2222 } else {
2223 goto rt_cache;
2224 }
2225 }
2226
2227 if (unlikely(fl4->flowi4_flags &
2228 FLOWI_FLAG_KNOWN_NH &&
2229 !(nh->nh_gw &&
2230 nh->nh_scope == RT_SCOPE_LINK))) {
2231 do_cache = false;
2232 goto add;
2233 }
2234 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2235 rth = rcu_dereference(*prth);
2236
2237 rt_cache:
2238 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2239 return rth;
2240 }
2241
2242 add:
2243 rth = rt_dst_alloc(dev_out, flags, type,
2244 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2245 IN_DEV_CONF_GET(in_dev, NOXFRM),
2246 do_cache);
2247 if (!rth)
2248 return ERR_PTR(-ENOBUFS);
2249
2250 rth->rt_iif = orig_oif ? : 0;
2251 if (res->table)
2252 rth->rt_table_id = res->table->tb_id;
2253
2254 RT_CACHE_STAT_INC(out_slow_tot);
2255
2256 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2257 if (flags & RTCF_LOCAL &&
2258 !(dev_out->flags & IFF_LOOPBACK)) {
2259 rth->dst.output = ip_mc_output;
2260 RT_CACHE_STAT_INC(out_slow_mc);
2261 }
2262 #ifdef CONFIG_IP_MROUTE
2263 if (type == RTN_MULTICAST) {
2264 if (IN_DEV_MFORWARD(in_dev) &&
2265 !ipv4_is_local_multicast(fl4->daddr)) {
2266 rth->dst.input = ip_mr_input;
2267 rth->dst.output = ip_mc_output;
2268 }
2269 }
2270 #endif
2271 }
2272
2273 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2274 set_lwt_redirect(rth);
2275
2276 return rth;
2277 }
2278
2279 /*
2280 * Major route resolver routine.
2281 */
2282
2283 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2284 const struct sk_buff *skb)
2285 {
2286 __u8 tos = RT_FL_TOS(fl4);
2287 struct fib_result res;
2288 struct rtable *rth;
2289
2290 res.tclassid = 0;
2291 res.fi = NULL;
2292 res.table = NULL;
2293
2294 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2295 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2296 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2297 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2298
2299 rcu_read_lock();
2300 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2301 rcu_read_unlock();
2302
2303 return rth;
2304 }
2305 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2306
2307 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2308 struct fib_result *res,
2309 const struct sk_buff *skb)
2310 {
2311 struct net_device *dev_out = NULL;
2312 int orig_oif = fl4->flowi4_oif;
2313 unsigned int flags = 0;
2314 struct rtable *rth;
2315 int err = -ENETUNREACH;
2316
2317 if (fl4->saddr) {
2318 rth = ERR_PTR(-EINVAL);
2319 if (ipv4_is_multicast(fl4->saddr) ||
2320 ipv4_is_lbcast(fl4->saddr) ||
2321 ipv4_is_zeronet(fl4->saddr))
2322 goto out;
2323
2324 /* I removed check for oif == dev_out->oif here.
2325 It was wrong for two reasons:
2326 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2327 is assigned to multiple interfaces.
2328 2. Moreover, we are allowed to send packets with saddr
2329 of another iface. --ANK
2330 */
2331
2332 if (fl4->flowi4_oif == 0 &&
2333 (ipv4_is_multicast(fl4->daddr) ||
2334 ipv4_is_lbcast(fl4->daddr))) {
2335 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2336 dev_out = __ip_dev_find(net, fl4->saddr, false);
2337 if (!dev_out)
2338 goto out;
2339
2340 /* Special hack: user can direct multicasts
2341 and limited broadcast via necessary interface
2342 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2343 This hack is not just for fun, it allows
2344 vic,vat and friends to work.
2345 They bind socket to loopback, set ttl to zero
2346 and expect that it will work.
2347 From the viewpoint of routing cache they are broken,
2348 because we are not allowed to build multicast path
2349 with loopback source addr (look, routing cache
2350 cannot know, that ttl is zero, so that packet
2351 will not leave this host and route is valid).
2352 Luckily, this hack is good workaround.
2353 */
2354
2355 fl4->flowi4_oif = dev_out->ifindex;
2356 goto make_route;
2357 }
2358
2359 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2360 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2361 if (!__ip_dev_find(net, fl4->saddr, false))
2362 goto out;
2363 }
2364 }
2365
2366
2367 if (fl4->flowi4_oif) {
2368 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2369 rth = ERR_PTR(-ENODEV);
2370 if (!dev_out)
2371 goto out;
2372
2373 /* RACE: Check return value of inet_select_addr instead. */
2374 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2375 rth = ERR_PTR(-ENETUNREACH);
2376 goto out;
2377 }
2378 if (ipv4_is_local_multicast(fl4->daddr) ||
2379 ipv4_is_lbcast(fl4->daddr) ||
2380 fl4->flowi4_proto == IPPROTO_IGMP) {
2381 if (!fl4->saddr)
2382 fl4->saddr = inet_select_addr(dev_out, 0,
2383 RT_SCOPE_LINK);
2384 goto make_route;
2385 }
2386 if (!fl4->saddr) {
2387 if (ipv4_is_multicast(fl4->daddr))
2388 fl4->saddr = inet_select_addr(dev_out, 0,
2389 fl4->flowi4_scope);
2390 else if (!fl4->daddr)
2391 fl4->saddr = inet_select_addr(dev_out, 0,
2392 RT_SCOPE_HOST);
2393 }
2394 }
2395
2396 if (!fl4->daddr) {
2397 fl4->daddr = fl4->saddr;
2398 if (!fl4->daddr)
2399 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2400 dev_out = net->loopback_dev;
2401 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2402 res->type = RTN_LOCAL;
2403 flags |= RTCF_LOCAL;
2404 goto make_route;
2405 }
2406
2407 err = fib_lookup(net, fl4, res, 0);
2408 if (err) {
2409 res->fi = NULL;
2410 res->table = NULL;
2411 if (fl4->flowi4_oif &&
2412 (ipv4_is_multicast(fl4->daddr) ||
2413 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2414 /* Apparently, routing tables are wrong. Assume,
2415 that the destination is on link.
2416
2417 WHY? DW.
2418 Because we are allowed to send to iface
2419 even if it has NO routes and NO assigned
2420 addresses. When oif is specified, routing
2421 tables are looked up with only one purpose:
2422 to catch if destination is gatewayed, rather than
2423 direct. Moreover, if MSG_DONTROUTE is set,
2424 we send packet, ignoring both routing tables
2425 and ifaddr state. --ANK
2426
2427
2428 We could make it even if oif is unknown,
2429 likely IPv6, but we do not.
2430 */
2431
2432 if (fl4->saddr == 0)
2433 fl4->saddr = inet_select_addr(dev_out, 0,
2434 RT_SCOPE_LINK);
2435 res->type = RTN_UNICAST;
2436 goto make_route;
2437 }
2438 rth = ERR_PTR(err);
2439 goto out;
2440 }
2441
2442 if (res->type == RTN_LOCAL) {
2443 if (!fl4->saddr) {
2444 if (res->fi->fib_prefsrc)
2445 fl4->saddr = res->fi->fib_prefsrc;
2446 else
2447 fl4->saddr = fl4->daddr;
2448 }
2449
2450 /* L3 master device is the loopback for that domain */
2451 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2452 net->loopback_dev;
2453 fl4->flowi4_oif = dev_out->ifindex;
2454 flags |= RTCF_LOCAL;
2455 goto make_route;
2456 }
2457
2458 fib_select_path(net, res, fl4, skb);
2459
2460 dev_out = FIB_RES_DEV(*res);
2461 fl4->flowi4_oif = dev_out->ifindex;
2462
2463
2464 make_route:
2465 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2466
2467 out:
2468 return rth;
2469 }
2470
2471 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2472 {
2473 return NULL;
2474 }
2475
2476 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2477 {
2478 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2479
2480 return mtu ? : dst->dev->mtu;
2481 }
2482
2483 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2484 struct sk_buff *skb, u32 mtu)
2485 {
2486 }
2487
2488 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2489 struct sk_buff *skb)
2490 {
2491 }
2492
2493 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2494 unsigned long old)
2495 {
2496 return NULL;
2497 }
2498
2499 static struct dst_ops ipv4_dst_blackhole_ops = {
2500 .family = AF_INET,
2501 .check = ipv4_blackhole_dst_check,
2502 .mtu = ipv4_blackhole_mtu,
2503 .default_advmss = ipv4_default_advmss,
2504 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2505 .redirect = ipv4_rt_blackhole_redirect,
2506 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2507 .neigh_lookup = ipv4_neigh_lookup,
2508 };
2509
2510 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2511 {
2512 struct rtable *ort = (struct rtable *) dst_orig;
2513 struct rtable *rt;
2514
2515 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2516 if (rt) {
2517 struct dst_entry *new = &rt->dst;
2518
2519 new->__use = 1;
2520 new->input = dst_discard;
2521 new->output = dst_discard_out;
2522
2523 new->dev = net->loopback_dev;
2524 if (new->dev)
2525 dev_hold(new->dev);
2526
2527 rt->rt_is_input = ort->rt_is_input;
2528 rt->rt_iif = ort->rt_iif;
2529 rt->rt_pmtu = ort->rt_pmtu;
2530
2531 rt->rt_genid = rt_genid_ipv4(net);
2532 rt->rt_flags = ort->rt_flags;
2533 rt->rt_type = ort->rt_type;
2534 rt->rt_gateway = ort->rt_gateway;
2535 rt->rt_uses_gateway = ort->rt_uses_gateway;
2536
2537 INIT_LIST_HEAD(&rt->rt_uncached);
2538 }
2539
2540 dst_release(dst_orig);
2541
2542 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2543 }
2544
2545 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2546 const struct sock *sk)
2547 {
2548 struct rtable *rt = __ip_route_output_key(net, flp4);
2549
2550 if (IS_ERR(rt))
2551 return rt;
2552
2553 if (flp4->flowi4_proto)
2554 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2555 flowi4_to_flowi(flp4),
2556 sk, 0);
2557
2558 return rt;
2559 }
2560 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2561
2562 /* called with rcu_read_lock held */
2563 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2564 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2565 u32 seq)
2566 {
2567 struct rtable *rt = skb_rtable(skb);
2568 struct rtmsg *r;
2569 struct nlmsghdr *nlh;
2570 unsigned long expires = 0;
2571 u32 error;
2572 u32 metrics[RTAX_MAX];
2573
2574 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2575 if (!nlh)
2576 return -EMSGSIZE;
2577
2578 r = nlmsg_data(nlh);
2579 r->rtm_family = AF_INET;
2580 r->rtm_dst_len = 32;
2581 r->rtm_src_len = 0;
2582 r->rtm_tos = fl4->flowi4_tos;
2583 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2584 if (nla_put_u32(skb, RTA_TABLE, table_id))
2585 goto nla_put_failure;
2586 r->rtm_type = rt->rt_type;
2587 r->rtm_scope = RT_SCOPE_UNIVERSE;
2588 r->rtm_protocol = RTPROT_UNSPEC;
2589 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2590 if (rt->rt_flags & RTCF_NOTIFY)
2591 r->rtm_flags |= RTM_F_NOTIFY;
2592 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2593 r->rtm_flags |= RTCF_DOREDIRECT;
2594
2595 if (nla_put_in_addr(skb, RTA_DST, dst))
2596 goto nla_put_failure;
2597 if (src) {
2598 r->rtm_src_len = 32;
2599 if (nla_put_in_addr(skb, RTA_SRC, src))
2600 goto nla_put_failure;
2601 }
2602 if (rt->dst.dev &&
2603 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2604 goto nla_put_failure;
2605 #ifdef CONFIG_IP_ROUTE_CLASSID
2606 if (rt->dst.tclassid &&
2607 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2608 goto nla_put_failure;
2609 #endif
2610 if (!rt_is_input_route(rt) &&
2611 fl4->saddr != src) {
2612 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2613 goto nla_put_failure;
2614 }
2615 if (rt->rt_uses_gateway &&
2616 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2617 goto nla_put_failure;
2618
2619 expires = rt->dst.expires;
2620 if (expires) {
2621 unsigned long now = jiffies;
2622
2623 if (time_before(now, expires))
2624 expires -= now;
2625 else
2626 expires = 0;
2627 }
2628
2629 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2630 if (rt->rt_pmtu && expires)
2631 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2632 if (rtnetlink_put_metrics(skb, metrics) < 0)
2633 goto nla_put_failure;
2634
2635 if (fl4->flowi4_mark &&
2636 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2637 goto nla_put_failure;
2638
2639 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2640 nla_put_u32(skb, RTA_UID,
2641 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2642 goto nla_put_failure;
2643
2644 error = rt->dst.error;
2645
2646 if (rt_is_input_route(rt)) {
2647 #ifdef CONFIG_IP_MROUTE
2648 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2649 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2650 int err = ipmr_get_route(net, skb,
2651 fl4->saddr, fl4->daddr,
2652 r, portid);
2653
2654 if (err <= 0) {
2655 if (err == 0)
2656 return 0;
2657 goto nla_put_failure;
2658 }
2659 } else
2660 #endif
2661 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2662 goto nla_put_failure;
2663 }
2664
2665 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2666 goto nla_put_failure;
2667
2668 nlmsg_end(skb, nlh);
2669 return 0;
2670
2671 nla_put_failure:
2672 nlmsg_cancel(skb, nlh);
2673 return -EMSGSIZE;
2674 }
2675
2676 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2677 struct netlink_ext_ack *extack)
2678 {
2679 struct net *net = sock_net(in_skb->sk);
2680 struct rtmsg *rtm;
2681 struct nlattr *tb[RTA_MAX+1];
2682 struct fib_result res = {};
2683 struct rtable *rt = NULL;
2684 struct flowi4 fl4;
2685 __be32 dst = 0;
2686 __be32 src = 0;
2687 u32 iif;
2688 int err;
2689 int mark;
2690 struct sk_buff *skb;
2691 u32 table_id = RT_TABLE_MAIN;
2692 kuid_t uid;
2693
2694 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2695 extack);
2696 if (err < 0)
2697 goto errout;
2698
2699 rtm = nlmsg_data(nlh);
2700
2701 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2702 if (!skb) {
2703 err = -ENOBUFS;
2704 goto errout;
2705 }
2706
2707 /* Reserve room for dummy headers, this skb can pass
2708 through good chunk of routing engine.
2709 */
2710 skb_reset_mac_header(skb);
2711 skb_reset_network_header(skb);
2712
2713 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2714 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2715 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2716 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2717 if (tb[RTA_UID])
2718 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2719 else
2720 uid = (iif ? INVALID_UID : current_uid());
2721
2722 /* Bugfix: need to give ip_route_input enough of an IP header to
2723 * not gag.
2724 */
2725 ip_hdr(skb)->protocol = IPPROTO_UDP;
2726 ip_hdr(skb)->saddr = src;
2727 ip_hdr(skb)->daddr = dst;
2728
2729 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2730
2731 memset(&fl4, 0, sizeof(fl4));
2732 fl4.daddr = dst;
2733 fl4.saddr = src;
2734 fl4.flowi4_tos = rtm->rtm_tos;
2735 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2736 fl4.flowi4_mark = mark;
2737 fl4.flowi4_uid = uid;
2738
2739 rcu_read_lock();
2740
2741 if (iif) {
2742 struct net_device *dev;
2743
2744 dev = dev_get_by_index_rcu(net, iif);
2745 if (!dev) {
2746 err = -ENODEV;
2747 goto errout_free;
2748 }
2749
2750 skb->protocol = htons(ETH_P_IP);
2751 skb->dev = dev;
2752 skb->mark = mark;
2753 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
2754 dev, &res);
2755
2756 rt = skb_rtable(skb);
2757 if (err == 0 && rt->dst.error)
2758 err = -rt->dst.error;
2759 } else {
2760 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
2761 err = 0;
2762 if (IS_ERR(rt))
2763 err = PTR_ERR(rt);
2764 else
2765 skb_dst_set(skb, &rt->dst);
2766 }
2767
2768 if (err)
2769 goto errout_free;
2770
2771 if (rtm->rtm_flags & RTM_F_NOTIFY)
2772 rt->rt_flags |= RTCF_NOTIFY;
2773
2774 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2775 table_id = rt->rt_table_id;
2776
2777 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2778 if (!res.fi) {
2779 err = fib_props[res.type].error;
2780 if (!err)
2781 err = -EHOSTUNREACH;
2782 goto errout_free;
2783 }
2784 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
2785 nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
2786 rt->rt_type, res.prefix, res.prefixlen,
2787 fl4.flowi4_tos, res.fi, 0);
2788 } else {
2789 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2790 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
2791 }
2792 if (err < 0)
2793 goto errout_free;
2794
2795 rcu_read_unlock();
2796
2797 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2798 errout:
2799 return err;
2800
2801 errout_free:
2802 rcu_read_unlock();
2803 kfree_skb(skb);
2804 goto errout;
2805 }
2806
2807 void ip_rt_multicast_event(struct in_device *in_dev)
2808 {
2809 rt_cache_flush(dev_net(in_dev->dev));
2810 }
2811
2812 #ifdef CONFIG_SYSCTL
2813 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2814 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2815 static int ip_rt_gc_elasticity __read_mostly = 8;
2816
2817 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2818 void __user *buffer,
2819 size_t *lenp, loff_t *ppos)
2820 {
2821 struct net *net = (struct net *)__ctl->extra1;
2822
2823 if (write) {
2824 rt_cache_flush(net);
2825 fnhe_genid_bump(net);
2826 return 0;
2827 }
2828
2829 return -EINVAL;
2830 }
2831
2832 static struct ctl_table ipv4_route_table[] = {
2833 {
2834 .procname = "gc_thresh",
2835 .data = &ipv4_dst_ops.gc_thresh,
2836 .maxlen = sizeof(int),
2837 .mode = 0644,
2838 .proc_handler = proc_dointvec,
2839 },
2840 {
2841 .procname = "max_size",
2842 .data = &ip_rt_max_size,
2843 .maxlen = sizeof(int),
2844 .mode = 0644,
2845 .proc_handler = proc_dointvec,
2846 },
2847 {
2848 /* Deprecated. Use gc_min_interval_ms */
2849
2850 .procname = "gc_min_interval",
2851 .data = &ip_rt_gc_min_interval,
2852 .maxlen = sizeof(int),
2853 .mode = 0644,
2854 .proc_handler = proc_dointvec_jiffies,
2855 },
2856 {
2857 .procname = "gc_min_interval_ms",
2858 .data = &ip_rt_gc_min_interval,
2859 .maxlen = sizeof(int),
2860 .mode = 0644,
2861 .proc_handler = proc_dointvec_ms_jiffies,
2862 },
2863 {
2864 .procname = "gc_timeout",
2865 .data = &ip_rt_gc_timeout,
2866 .maxlen = sizeof(int),
2867 .mode = 0644,
2868 .proc_handler = proc_dointvec_jiffies,
2869 },
2870 {
2871 .procname = "gc_interval",
2872 .data = &ip_rt_gc_interval,
2873 .maxlen = sizeof(int),
2874 .mode = 0644,
2875 .proc_handler = proc_dointvec_jiffies,
2876 },
2877 {
2878 .procname = "redirect_load",
2879 .data = &ip_rt_redirect_load,
2880 .maxlen = sizeof(int),
2881 .mode = 0644,
2882 .proc_handler = proc_dointvec,
2883 },
2884 {
2885 .procname = "redirect_number",
2886 .data = &ip_rt_redirect_number,
2887 .maxlen = sizeof(int),
2888 .mode = 0644,
2889 .proc_handler = proc_dointvec,
2890 },
2891 {
2892 .procname = "redirect_silence",
2893 .data = &ip_rt_redirect_silence,
2894 .maxlen = sizeof(int),
2895 .mode = 0644,
2896 .proc_handler = proc_dointvec,
2897 },
2898 {
2899 .procname = "error_cost",
2900 .data = &ip_rt_error_cost,
2901 .maxlen = sizeof(int),
2902 .mode = 0644,
2903 .proc_handler = proc_dointvec,
2904 },
2905 {
2906 .procname = "error_burst",
2907 .data = &ip_rt_error_burst,
2908 .maxlen = sizeof(int),
2909 .mode = 0644,
2910 .proc_handler = proc_dointvec,
2911 },
2912 {
2913 .procname = "gc_elasticity",
2914 .data = &ip_rt_gc_elasticity,
2915 .maxlen = sizeof(int),
2916 .mode = 0644,
2917 .proc_handler = proc_dointvec,
2918 },
2919 {
2920 .procname = "mtu_expires",
2921 .data = &ip_rt_mtu_expires,
2922 .maxlen = sizeof(int),
2923 .mode = 0644,
2924 .proc_handler = proc_dointvec_jiffies,
2925 },
2926 {
2927 .procname = "min_pmtu",
2928 .data = &ip_rt_min_pmtu,
2929 .maxlen = sizeof(int),
2930 .mode = 0644,
2931 .proc_handler = proc_dointvec,
2932 },
2933 {
2934 .procname = "min_adv_mss",
2935 .data = &ip_rt_min_advmss,
2936 .maxlen = sizeof(int),
2937 .mode = 0644,
2938 .proc_handler = proc_dointvec,
2939 },
2940 { }
2941 };
2942
2943 static struct ctl_table ipv4_route_flush_table[] = {
2944 {
2945 .procname = "flush",
2946 .maxlen = sizeof(int),
2947 .mode = 0200,
2948 .proc_handler = ipv4_sysctl_rtcache_flush,
2949 },
2950 { },
2951 };
2952
2953 static __net_init int sysctl_route_net_init(struct net *net)
2954 {
2955 struct ctl_table *tbl;
2956
2957 tbl = ipv4_route_flush_table;
2958 if (!net_eq(net, &init_net)) {
2959 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2960 if (!tbl)
2961 goto err_dup;
2962
2963 /* Don't export sysctls to unprivileged users */
2964 if (net->user_ns != &init_user_ns)
2965 tbl[0].procname = NULL;
2966 }
2967 tbl[0].extra1 = net;
2968
2969 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2970 if (!net->ipv4.route_hdr)
2971 goto err_reg;
2972 return 0;
2973
2974 err_reg:
2975 if (tbl != ipv4_route_flush_table)
2976 kfree(tbl);
2977 err_dup:
2978 return -ENOMEM;
2979 }
2980
2981 static __net_exit void sysctl_route_net_exit(struct net *net)
2982 {
2983 struct ctl_table *tbl;
2984
2985 tbl = net->ipv4.route_hdr->ctl_table_arg;
2986 unregister_net_sysctl_table(net->ipv4.route_hdr);
2987 BUG_ON(tbl == ipv4_route_flush_table);
2988 kfree(tbl);
2989 }
2990
2991 static __net_initdata struct pernet_operations sysctl_route_ops = {
2992 .init = sysctl_route_net_init,
2993 .exit = sysctl_route_net_exit,
2994 };
2995 #endif
2996
2997 static __net_init int rt_genid_init(struct net *net)
2998 {
2999 atomic_set(&net->ipv4.rt_genid, 0);
3000 atomic_set(&net->fnhe_genid, 0);
3001 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3002 return 0;
3003 }
3004
3005 static __net_initdata struct pernet_operations rt_genid_ops = {
3006 .init = rt_genid_init,
3007 };
3008
3009 static int __net_init ipv4_inetpeer_init(struct net *net)
3010 {
3011 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3012
3013 if (!bp)
3014 return -ENOMEM;
3015 inet_peer_base_init(bp);
3016 net->ipv4.peers = bp;
3017 return 0;
3018 }
3019
3020 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3021 {
3022 struct inet_peer_base *bp = net->ipv4.peers;
3023
3024 net->ipv4.peers = NULL;
3025 inetpeer_invalidate_tree(bp);
3026 kfree(bp);
3027 }
3028
3029 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3030 .init = ipv4_inetpeer_init,
3031 .exit = ipv4_inetpeer_exit,
3032 };
3033
3034 #ifdef CONFIG_IP_ROUTE_CLASSID
3035 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3036 #endif /* CONFIG_IP_ROUTE_CLASSID */
3037
3038 int __init ip_rt_init(void)
3039 {
3040 int rc = 0;
3041 int cpu;
3042
3043 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
3044 if (!ip_idents)
3045 panic("IP: failed to allocate ip_idents\n");
3046
3047 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3048
3049 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3050 if (!ip_tstamps)
3051 panic("IP: failed to allocate ip_tstamps\n");
3052
3053 for_each_possible_cpu(cpu) {
3054 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3055
3056 INIT_LIST_HEAD(&ul->head);
3057 spin_lock_init(&ul->lock);
3058 }
3059 #ifdef CONFIG_IP_ROUTE_CLASSID
3060 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3061 if (!ip_rt_acct)
3062 panic("IP: failed to allocate ip_rt_acct\n");
3063 #endif
3064
3065 ipv4_dst_ops.kmem_cachep =
3066 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3067 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3068
3069 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3070
3071 if (dst_entries_init(&ipv4_dst_ops) < 0)
3072 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3073
3074 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3075 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3076
3077 ipv4_dst_ops.gc_thresh = ~0;
3078 ip_rt_max_size = INT_MAX;
3079
3080 devinet_init();
3081 ip_fib_init();
3082
3083 if (ip_rt_proc_init())
3084 pr_err("Unable to create route proc files\n");
3085 #ifdef CONFIG_XFRM
3086 xfrm_init();
3087 xfrm4_init();
3088 #endif
3089 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
3090
3091 #ifdef CONFIG_SYSCTL
3092 register_pernet_subsys(&sysctl_route_ops);
3093 #endif
3094 register_pernet_subsys(&rt_genid_ops);
3095 register_pernet_subsys(&ipv4_inetpeer_ops);
3096 return rc;
3097 }
3098
3099 #ifdef CONFIG_SYSCTL
3100 /*
3101 * We really need to sanitize the damn ipv4 init order, then all
3102 * this nonsense will go away.
3103 */
3104 void __init ip_static_sysctl_init(void)
3105 {
3106 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3107 }
3108 #endif
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