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Merge tag 'usb-4.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
[mirror_ubuntu-eoan-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 #endif
112 #include <net/secure_seq.h>
113 #include <net/ip_tunnels.h>
114 #include <net/l3mdev.h>
115
116 #include "fib_lookup.h"
117
118 #define RT_FL_TOS(oldflp4) \
119 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
120
121 #define RT_GC_TIMEOUT (300*HZ)
122
123 static int ip_rt_max_size;
124 static int ip_rt_redirect_number __read_mostly = 9;
125 static int ip_rt_redirect_load __read_mostly = HZ / 50;
126 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
127 static int ip_rt_error_cost __read_mostly = HZ;
128 static int ip_rt_error_burst __read_mostly = 5 * HZ;
129 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
130 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
131 static int ip_rt_min_advmss __read_mostly = 256;
132
133 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
134
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 .open = rt_cache_seq_open,
244 .read = seq_read,
245 .llseek = seq_lseek,
246 .release = seq_release,
247 };
248
249
250 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
251 {
252 int cpu;
253
254 if (*pos == 0)
255 return SEQ_START_TOKEN;
256
257 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
258 if (!cpu_possible(cpu))
259 continue;
260 *pos = cpu+1;
261 return &per_cpu(rt_cache_stat, cpu);
262 }
263 return NULL;
264 }
265
266 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
267 {
268 int cpu;
269
270 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
271 if (!cpu_possible(cpu))
272 continue;
273 *pos = cpu+1;
274 return &per_cpu(rt_cache_stat, cpu);
275 }
276 return NULL;
277
278 }
279
280 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
281 {
282
283 }
284
285 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
286 {
287 struct rt_cache_stat *st = v;
288
289 if (v == SEQ_START_TOKEN) {
290 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");
291 return 0;
292 }
293
294 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
295 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
296 dst_entries_get_slow(&ipv4_dst_ops),
297 0, /* st->in_hit */
298 st->in_slow_tot,
299 st->in_slow_mc,
300 st->in_no_route,
301 st->in_brd,
302 st->in_martian_dst,
303 st->in_martian_src,
304
305 0, /* st->out_hit */
306 st->out_slow_tot,
307 st->out_slow_mc,
308
309 0, /* st->gc_total */
310 0, /* st->gc_ignored */
311 0, /* st->gc_goal_miss */
312 0, /* st->gc_dst_overflow */
313 0, /* st->in_hlist_search */
314 0 /* st->out_hlist_search */
315 );
316 return 0;
317 }
318
319 static const struct seq_operations rt_cpu_seq_ops = {
320 .start = rt_cpu_seq_start,
321 .next = rt_cpu_seq_next,
322 .stop = rt_cpu_seq_stop,
323 .show = rt_cpu_seq_show,
324 };
325
326
327 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
328 {
329 return seq_open(file, &rt_cpu_seq_ops);
330 }
331
332 static const struct file_operations rt_cpu_seq_fops = {
333 .open = rt_cpu_seq_open,
334 .read = seq_read,
335 .llseek = seq_lseek,
336 .release = seq_release,
337 };
338
339 #ifdef CONFIG_IP_ROUTE_CLASSID
340 static int rt_acct_proc_show(struct seq_file *m, void *v)
341 {
342 struct ip_rt_acct *dst, *src;
343 unsigned int i, j;
344
345 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
346 if (!dst)
347 return -ENOMEM;
348
349 for_each_possible_cpu(i) {
350 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
351 for (j = 0; j < 256; j++) {
352 dst[j].o_bytes += src[j].o_bytes;
353 dst[j].o_packets += src[j].o_packets;
354 dst[j].i_bytes += src[j].i_bytes;
355 dst[j].i_packets += src[j].i_packets;
356 }
357 }
358
359 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
360 kfree(dst);
361 return 0;
362 }
363
364 static int rt_acct_proc_open(struct inode *inode, struct file *file)
365 {
366 return single_open(file, rt_acct_proc_show, NULL);
367 }
368
369 static const struct file_operations rt_acct_proc_fops = {
370 .open = rt_acct_proc_open,
371 .read = seq_read,
372 .llseek = seq_lseek,
373 .release = single_release,
374 };
375 #endif
376
377 static int __net_init ip_rt_do_proc_init(struct net *net)
378 {
379 struct proc_dir_entry *pde;
380
381 pde = proc_create("rt_cache", 0444, net->proc_net,
382 &rt_cache_seq_fops);
383 if (!pde)
384 goto err1;
385
386 pde = proc_create("rt_cache", 0444,
387 net->proc_net_stat, &rt_cpu_seq_fops);
388 if (!pde)
389 goto err2;
390
391 #ifdef CONFIG_IP_ROUTE_CLASSID
392 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
393 if (!pde)
394 goto err3;
395 #endif
396 return 0;
397
398 #ifdef CONFIG_IP_ROUTE_CLASSID
399 err3:
400 remove_proc_entry("rt_cache", net->proc_net_stat);
401 #endif
402 err2:
403 remove_proc_entry("rt_cache", net->proc_net);
404 err1:
405 return -ENOMEM;
406 }
407
408 static void __net_exit ip_rt_do_proc_exit(struct net *net)
409 {
410 remove_proc_entry("rt_cache", net->proc_net_stat);
411 remove_proc_entry("rt_cache", net->proc_net);
412 #ifdef CONFIG_IP_ROUTE_CLASSID
413 remove_proc_entry("rt_acct", net->proc_net);
414 #endif
415 }
416
417 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
418 .init = ip_rt_do_proc_init,
419 .exit = ip_rt_do_proc_exit,
420 };
421
422 static int __init ip_rt_proc_init(void)
423 {
424 return register_pernet_subsys(&ip_rt_proc_ops);
425 }
426
427 #else
428 static inline int ip_rt_proc_init(void)
429 {
430 return 0;
431 }
432 #endif /* CONFIG_PROC_FS */
433
434 static inline bool rt_is_expired(const struct rtable *rth)
435 {
436 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
437 }
438
439 void rt_cache_flush(struct net *net)
440 {
441 rt_genid_bump_ipv4(net);
442 }
443
444 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
445 struct sk_buff *skb,
446 const void *daddr)
447 {
448 struct net_device *dev = dst->dev;
449 const __be32 *pkey = daddr;
450 const struct rtable *rt;
451 struct neighbour *n;
452
453 rt = (const struct rtable *) dst;
454 if (rt->rt_gateway)
455 pkey = (const __be32 *) &rt->rt_gateway;
456 else if (skb)
457 pkey = &ip_hdr(skb)->daddr;
458
459 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
460 if (n)
461 return n;
462 return neigh_create(&arp_tbl, pkey, dev);
463 }
464
465 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
466 {
467 struct net_device *dev = dst->dev;
468 const __be32 *pkey = daddr;
469 const struct rtable *rt;
470
471 rt = (const struct rtable *)dst;
472 if (rt->rt_gateway)
473 pkey = (const __be32 *)&rt->rt_gateway;
474 else if (!daddr ||
475 (rt->rt_flags &
476 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
477 return;
478
479 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
480 }
481
482 #define IP_IDENTS_SZ 2048u
483
484 static atomic_t *ip_idents __read_mostly;
485 static u32 *ip_tstamps __read_mostly;
486
487 /* In order to protect privacy, we add a perturbation to identifiers
488 * if one generator is seldom used. This makes hard for an attacker
489 * to infer how many packets were sent between two points in time.
490 */
491 u32 ip_idents_reserve(u32 hash, int segs)
492 {
493 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
494 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
495 u32 old = READ_ONCE(*p_tstamp);
496 u32 now = (u32)jiffies;
497 u32 new, delta = 0;
498
499 if (old != now && cmpxchg(p_tstamp, old, now) == old)
500 delta = prandom_u32_max(now - old);
501
502 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
503 do {
504 old = (u32)atomic_read(p_id);
505 new = old + delta + segs;
506 } while (atomic_cmpxchg(p_id, old, new) != old);
507
508 return new - segs;
509 }
510 EXPORT_SYMBOL(ip_idents_reserve);
511
512 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
513 {
514 static u32 ip_idents_hashrnd __read_mostly;
515 u32 hash, id;
516
517 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
518
519 hash = jhash_3words((__force u32)iph->daddr,
520 (__force u32)iph->saddr,
521 iph->protocol ^ net_hash_mix(net),
522 ip_idents_hashrnd);
523 id = ip_idents_reserve(hash, segs);
524 iph->id = htons(id);
525 }
526 EXPORT_SYMBOL(__ip_select_ident);
527
528 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
529 const struct sock *sk,
530 const struct iphdr *iph,
531 int oif, u8 tos,
532 u8 prot, u32 mark, int flow_flags)
533 {
534 if (sk) {
535 const struct inet_sock *inet = inet_sk(sk);
536
537 oif = sk->sk_bound_dev_if;
538 mark = sk->sk_mark;
539 tos = RT_CONN_FLAGS(sk);
540 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
541 }
542 flowi4_init_output(fl4, oif, mark, tos,
543 RT_SCOPE_UNIVERSE, prot,
544 flow_flags,
545 iph->daddr, iph->saddr, 0, 0,
546 sock_net_uid(net, sk));
547 }
548
549 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
550 const struct sock *sk)
551 {
552 const struct net *net = dev_net(skb->dev);
553 const struct iphdr *iph = ip_hdr(skb);
554 int oif = skb->dev->ifindex;
555 u8 tos = RT_TOS(iph->tos);
556 u8 prot = iph->protocol;
557 u32 mark = skb->mark;
558
559 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
560 }
561
562 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
563 {
564 const struct inet_sock *inet = inet_sk(sk);
565 const struct ip_options_rcu *inet_opt;
566 __be32 daddr = inet->inet_daddr;
567
568 rcu_read_lock();
569 inet_opt = rcu_dereference(inet->inet_opt);
570 if (inet_opt && inet_opt->opt.srr)
571 daddr = inet_opt->opt.faddr;
572 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
573 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
574 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
575 inet_sk_flowi_flags(sk),
576 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
577 rcu_read_unlock();
578 }
579
580 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
581 const struct sk_buff *skb)
582 {
583 if (skb)
584 build_skb_flow_key(fl4, skb, sk);
585 else
586 build_sk_flow_key(fl4, sk);
587 }
588
589 static DEFINE_SPINLOCK(fnhe_lock);
590
591 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
592 {
593 struct rtable *rt;
594
595 rt = rcu_dereference(fnhe->fnhe_rth_input);
596 if (rt) {
597 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
598 dst_dev_put(&rt->dst);
599 dst_release(&rt->dst);
600 }
601 rt = rcu_dereference(fnhe->fnhe_rth_output);
602 if (rt) {
603 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
604 dst_dev_put(&rt->dst);
605 dst_release(&rt->dst);
606 }
607 }
608
609 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
610 {
611 struct fib_nh_exception *fnhe, *oldest;
612
613 oldest = rcu_dereference(hash->chain);
614 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
615 fnhe = rcu_dereference(fnhe->fnhe_next)) {
616 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
617 oldest = fnhe;
618 }
619 fnhe_flush_routes(oldest);
620 return oldest;
621 }
622
623 static inline u32 fnhe_hashfun(__be32 daddr)
624 {
625 static u32 fnhe_hashrnd __read_mostly;
626 u32 hval;
627
628 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
629 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
630 return hash_32(hval, FNHE_HASH_SHIFT);
631 }
632
633 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
634 {
635 rt->rt_pmtu = fnhe->fnhe_pmtu;
636 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
637 rt->dst.expires = fnhe->fnhe_expires;
638
639 if (fnhe->fnhe_gw) {
640 rt->rt_flags |= RTCF_REDIRECTED;
641 rt->rt_gateway = fnhe->fnhe_gw;
642 rt->rt_uses_gateway = 1;
643 }
644 }
645
646 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
647 u32 pmtu, bool lock, unsigned long expires)
648 {
649 struct fnhe_hash_bucket *hash;
650 struct fib_nh_exception *fnhe;
651 struct rtable *rt;
652 u32 genid, hval;
653 unsigned int i;
654 int depth;
655
656 genid = fnhe_genid(dev_net(nh->nh_dev));
657 hval = fnhe_hashfun(daddr);
658
659 spin_lock_bh(&fnhe_lock);
660
661 hash = rcu_dereference(nh->nh_exceptions);
662 if (!hash) {
663 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
664 if (!hash)
665 goto out_unlock;
666 rcu_assign_pointer(nh->nh_exceptions, hash);
667 }
668
669 hash += hval;
670
671 depth = 0;
672 for (fnhe = rcu_dereference(hash->chain); fnhe;
673 fnhe = rcu_dereference(fnhe->fnhe_next)) {
674 if (fnhe->fnhe_daddr == daddr)
675 break;
676 depth++;
677 }
678
679 if (fnhe) {
680 if (fnhe->fnhe_genid != genid)
681 fnhe->fnhe_genid = genid;
682 if (gw)
683 fnhe->fnhe_gw = gw;
684 if (pmtu) {
685 fnhe->fnhe_pmtu = pmtu;
686 fnhe->fnhe_mtu_locked = lock;
687 }
688 fnhe->fnhe_expires = max(1UL, expires);
689 /* Update all cached dsts too */
690 rt = rcu_dereference(fnhe->fnhe_rth_input);
691 if (rt)
692 fill_route_from_fnhe(rt, fnhe);
693 rt = rcu_dereference(fnhe->fnhe_rth_output);
694 if (rt)
695 fill_route_from_fnhe(rt, fnhe);
696 } else {
697 if (depth > FNHE_RECLAIM_DEPTH)
698 fnhe = fnhe_oldest(hash);
699 else {
700 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
701 if (!fnhe)
702 goto out_unlock;
703
704 fnhe->fnhe_next = hash->chain;
705 rcu_assign_pointer(hash->chain, fnhe);
706 }
707 fnhe->fnhe_genid = genid;
708 fnhe->fnhe_daddr = daddr;
709 fnhe->fnhe_gw = gw;
710 fnhe->fnhe_pmtu = pmtu;
711 fnhe->fnhe_mtu_locked = lock;
712 fnhe->fnhe_expires = max(1UL, expires);
713
714 /* Exception created; mark the cached routes for the nexthop
715 * stale, so anyone caching it rechecks if this exception
716 * applies to them.
717 */
718 rt = rcu_dereference(nh->nh_rth_input);
719 if (rt)
720 rt->dst.obsolete = DST_OBSOLETE_KILL;
721
722 for_each_possible_cpu(i) {
723 struct rtable __rcu **prt;
724 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
725 rt = rcu_dereference(*prt);
726 if (rt)
727 rt->dst.obsolete = DST_OBSOLETE_KILL;
728 }
729 }
730
731 fnhe->fnhe_stamp = jiffies;
732
733 out_unlock:
734 spin_unlock_bh(&fnhe_lock);
735 }
736
737 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
738 bool kill_route)
739 {
740 __be32 new_gw = icmp_hdr(skb)->un.gateway;
741 __be32 old_gw = ip_hdr(skb)->saddr;
742 struct net_device *dev = skb->dev;
743 struct in_device *in_dev;
744 struct fib_result res;
745 struct neighbour *n;
746 struct net *net;
747
748 switch (icmp_hdr(skb)->code & 7) {
749 case ICMP_REDIR_NET:
750 case ICMP_REDIR_NETTOS:
751 case ICMP_REDIR_HOST:
752 case ICMP_REDIR_HOSTTOS:
753 break;
754
755 default:
756 return;
757 }
758
759 if (rt->rt_gateway != old_gw)
760 return;
761
762 in_dev = __in_dev_get_rcu(dev);
763 if (!in_dev)
764 return;
765
766 net = dev_net(dev);
767 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
768 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
769 ipv4_is_zeronet(new_gw))
770 goto reject_redirect;
771
772 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
773 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
774 goto reject_redirect;
775 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
776 goto reject_redirect;
777 } else {
778 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
779 goto reject_redirect;
780 }
781
782 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
783 if (!n)
784 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
785 if (!IS_ERR(n)) {
786 if (!(n->nud_state & NUD_VALID)) {
787 neigh_event_send(n, NULL);
788 } else {
789 if (fib_lookup(net, fl4, &res, 0) == 0) {
790 struct fib_nh *nh = &FIB_RES_NH(res);
791
792 update_or_create_fnhe(nh, fl4->daddr, new_gw,
793 0, false,
794 jiffies + ip_rt_gc_timeout);
795 }
796 if (kill_route)
797 rt->dst.obsolete = DST_OBSOLETE_KILL;
798 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
799 }
800 neigh_release(n);
801 }
802 return;
803
804 reject_redirect:
805 #ifdef CONFIG_IP_ROUTE_VERBOSE
806 if (IN_DEV_LOG_MARTIANS(in_dev)) {
807 const struct iphdr *iph = (const struct iphdr *) skb->data;
808 __be32 daddr = iph->daddr;
809 __be32 saddr = iph->saddr;
810
811 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
812 " Advised path = %pI4 -> %pI4\n",
813 &old_gw, dev->name, &new_gw,
814 &saddr, &daddr);
815 }
816 #endif
817 ;
818 }
819
820 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
821 {
822 struct rtable *rt;
823 struct flowi4 fl4;
824 const struct iphdr *iph = (const struct iphdr *) skb->data;
825 struct net *net = dev_net(skb->dev);
826 int oif = skb->dev->ifindex;
827 u8 tos = RT_TOS(iph->tos);
828 u8 prot = iph->protocol;
829 u32 mark = skb->mark;
830
831 rt = (struct rtable *) dst;
832
833 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
834 __ip_do_redirect(rt, skb, &fl4, true);
835 }
836
837 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
838 {
839 struct rtable *rt = (struct rtable *)dst;
840 struct dst_entry *ret = dst;
841
842 if (rt) {
843 if (dst->obsolete > 0) {
844 ip_rt_put(rt);
845 ret = NULL;
846 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
847 rt->dst.expires) {
848 ip_rt_put(rt);
849 ret = NULL;
850 }
851 }
852 return ret;
853 }
854
855 /*
856 * Algorithm:
857 * 1. The first ip_rt_redirect_number redirects are sent
858 * with exponential backoff, then we stop sending them at all,
859 * assuming that the host ignores our redirects.
860 * 2. If we did not see packets requiring redirects
861 * during ip_rt_redirect_silence, we assume that the host
862 * forgot redirected route and start to send redirects again.
863 *
864 * This algorithm is much cheaper and more intelligent than dumb load limiting
865 * in icmp.c.
866 *
867 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
868 * and "frag. need" (breaks PMTU discovery) in icmp.c.
869 */
870
871 void ip_rt_send_redirect(struct sk_buff *skb)
872 {
873 struct rtable *rt = skb_rtable(skb);
874 struct in_device *in_dev;
875 struct inet_peer *peer;
876 struct net *net;
877 int log_martians;
878 int vif;
879
880 rcu_read_lock();
881 in_dev = __in_dev_get_rcu(rt->dst.dev);
882 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
883 rcu_read_unlock();
884 return;
885 }
886 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
887 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
888 rcu_read_unlock();
889
890 net = dev_net(rt->dst.dev);
891 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
892 if (!peer) {
893 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
894 rt_nexthop(rt, ip_hdr(skb)->daddr));
895 return;
896 }
897
898 /* No redirected packets during ip_rt_redirect_silence;
899 * reset the algorithm.
900 */
901 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
902 peer->rate_tokens = 0;
903
904 /* Too many ignored redirects; do not send anything
905 * set dst.rate_last to the last seen redirected packet.
906 */
907 if (peer->rate_tokens >= ip_rt_redirect_number) {
908 peer->rate_last = jiffies;
909 goto out_put_peer;
910 }
911
912 /* Check for load limit; set rate_last to the latest sent
913 * redirect.
914 */
915 if (peer->rate_tokens == 0 ||
916 time_after(jiffies,
917 (peer->rate_last +
918 (ip_rt_redirect_load << peer->rate_tokens)))) {
919 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
920
921 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
922 peer->rate_last = jiffies;
923 ++peer->rate_tokens;
924 #ifdef CONFIG_IP_ROUTE_VERBOSE
925 if (log_martians &&
926 peer->rate_tokens == ip_rt_redirect_number)
927 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
928 &ip_hdr(skb)->saddr, inet_iif(skb),
929 &ip_hdr(skb)->daddr, &gw);
930 #endif
931 }
932 out_put_peer:
933 inet_putpeer(peer);
934 }
935
936 static int ip_error(struct sk_buff *skb)
937 {
938 struct rtable *rt = skb_rtable(skb);
939 struct net_device *dev = skb->dev;
940 struct in_device *in_dev;
941 struct inet_peer *peer;
942 unsigned long now;
943 struct net *net;
944 bool send;
945 int code;
946
947 if (netif_is_l3_master(skb->dev)) {
948 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
949 if (!dev)
950 goto out;
951 }
952
953 in_dev = __in_dev_get_rcu(dev);
954
955 /* IP on this device is disabled. */
956 if (!in_dev)
957 goto out;
958
959 net = dev_net(rt->dst.dev);
960 if (!IN_DEV_FORWARD(in_dev)) {
961 switch (rt->dst.error) {
962 case EHOSTUNREACH:
963 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
964 break;
965
966 case ENETUNREACH:
967 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
968 break;
969 }
970 goto out;
971 }
972
973 switch (rt->dst.error) {
974 case EINVAL:
975 default:
976 goto out;
977 case EHOSTUNREACH:
978 code = ICMP_HOST_UNREACH;
979 break;
980 case ENETUNREACH:
981 code = ICMP_NET_UNREACH;
982 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
983 break;
984 case EACCES:
985 code = ICMP_PKT_FILTERED;
986 break;
987 }
988
989 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
990 l3mdev_master_ifindex(skb->dev), 1);
991
992 send = true;
993 if (peer) {
994 now = jiffies;
995 peer->rate_tokens += now - peer->rate_last;
996 if (peer->rate_tokens > ip_rt_error_burst)
997 peer->rate_tokens = ip_rt_error_burst;
998 peer->rate_last = now;
999 if (peer->rate_tokens >= ip_rt_error_cost)
1000 peer->rate_tokens -= ip_rt_error_cost;
1001 else
1002 send = false;
1003 inet_putpeer(peer);
1004 }
1005 if (send)
1006 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1007
1008 out: kfree_skb(skb);
1009 return 0;
1010 }
1011
1012 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1013 {
1014 struct dst_entry *dst = &rt->dst;
1015 struct fib_result res;
1016 bool lock = false;
1017
1018 if (ip_mtu_locked(dst))
1019 return;
1020
1021 if (ipv4_mtu(dst) < mtu)
1022 return;
1023
1024 if (mtu < ip_rt_min_pmtu) {
1025 lock = true;
1026 mtu = ip_rt_min_pmtu;
1027 }
1028
1029 if (rt->rt_pmtu == mtu &&
1030 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1031 return;
1032
1033 rcu_read_lock();
1034 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1035 struct fib_nh *nh = &FIB_RES_NH(res);
1036
1037 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock,
1038 jiffies + ip_rt_mtu_expires);
1039 }
1040 rcu_read_unlock();
1041 }
1042
1043 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1044 struct sk_buff *skb, u32 mtu)
1045 {
1046 struct rtable *rt = (struct rtable *) dst;
1047 struct flowi4 fl4;
1048
1049 ip_rt_build_flow_key(&fl4, sk, skb);
1050 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 }
1052
1053 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1054 int oif, u32 mark, u8 protocol, int flow_flags)
1055 {
1056 const struct iphdr *iph = (const struct iphdr *) skb->data;
1057 struct flowi4 fl4;
1058 struct rtable *rt;
1059
1060 if (!mark)
1061 mark = IP4_REPLY_MARK(net, skb->mark);
1062
1063 __build_flow_key(net, &fl4, NULL, iph, oif,
1064 RT_TOS(iph->tos), protocol, mark, flow_flags);
1065 rt = __ip_route_output_key(net, &fl4);
1066 if (!IS_ERR(rt)) {
1067 __ip_rt_update_pmtu(rt, &fl4, mtu);
1068 ip_rt_put(rt);
1069 }
1070 }
1071 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1072
1073 static 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
1079 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1080
1081 if (!fl4.flowi4_mark)
1082 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1083
1084 rt = __ip_route_output_key(sock_net(sk), &fl4);
1085 if (!IS_ERR(rt)) {
1086 __ip_rt_update_pmtu(rt, &fl4, mtu);
1087 ip_rt_put(rt);
1088 }
1089 }
1090
1091 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1092 {
1093 const struct iphdr *iph = (const struct iphdr *) skb->data;
1094 struct flowi4 fl4;
1095 struct rtable *rt;
1096 struct dst_entry *odst = NULL;
1097 bool new = false;
1098 struct net *net = sock_net(sk);
1099
1100 bh_lock_sock(sk);
1101
1102 if (!ip_sk_accept_pmtu(sk))
1103 goto out;
1104
1105 odst = sk_dst_get(sk);
1106
1107 if (sock_owned_by_user(sk) || !odst) {
1108 __ipv4_sk_update_pmtu(skb, sk, mtu);
1109 goto out;
1110 }
1111
1112 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1113
1114 rt = (struct rtable *)odst;
1115 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1116 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1117 if (IS_ERR(rt))
1118 goto out;
1119
1120 new = true;
1121 }
1122
1123 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1124
1125 if (!dst_check(&rt->dst, 0)) {
1126 if (new)
1127 dst_release(&rt->dst);
1128
1129 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1130 if (IS_ERR(rt))
1131 goto out;
1132
1133 new = true;
1134 }
1135
1136 if (new)
1137 sk_dst_set(sk, &rt->dst);
1138
1139 out:
1140 bh_unlock_sock(sk);
1141 dst_release(odst);
1142 }
1143 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1144
1145 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1146 int oif, u32 mark, u8 protocol, int flow_flags)
1147 {
1148 const struct iphdr *iph = (const struct iphdr *) skb->data;
1149 struct flowi4 fl4;
1150 struct rtable *rt;
1151
1152 __build_flow_key(net, &fl4, NULL, iph, oif,
1153 RT_TOS(iph->tos), protocol, mark, flow_flags);
1154 rt = __ip_route_output_key(net, &fl4);
1155 if (!IS_ERR(rt)) {
1156 __ip_do_redirect(rt, skb, &fl4, false);
1157 ip_rt_put(rt);
1158 }
1159 }
1160 EXPORT_SYMBOL_GPL(ipv4_redirect);
1161
1162 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1163 {
1164 const struct iphdr *iph = (const struct iphdr *) skb->data;
1165 struct flowi4 fl4;
1166 struct rtable *rt;
1167 struct net *net = sock_net(sk);
1168
1169 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1170 rt = __ip_route_output_key(net, &fl4);
1171 if (!IS_ERR(rt)) {
1172 __ip_do_redirect(rt, skb, &fl4, false);
1173 ip_rt_put(rt);
1174 }
1175 }
1176 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1177
1178 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1179 {
1180 struct rtable *rt = (struct rtable *) dst;
1181
1182 /* All IPV4 dsts are created with ->obsolete set to the value
1183 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1184 * into this function always.
1185 *
1186 * When a PMTU/redirect information update invalidates a route,
1187 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1188 * DST_OBSOLETE_DEAD by dst_free().
1189 */
1190 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1191 return NULL;
1192 return dst;
1193 }
1194
1195 static void ipv4_link_failure(struct sk_buff *skb)
1196 {
1197 struct rtable *rt;
1198
1199 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1200
1201 rt = skb_rtable(skb);
1202 if (rt)
1203 dst_set_expires(&rt->dst, 0);
1204 }
1205
1206 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1207 {
1208 pr_debug("%s: %pI4 -> %pI4, %s\n",
1209 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1210 skb->dev ? skb->dev->name : "?");
1211 kfree_skb(skb);
1212 WARN_ON(1);
1213 return 0;
1214 }
1215
1216 /*
1217 We do not cache source address of outgoing interface,
1218 because it is used only by IP RR, TS and SRR options,
1219 so that it out of fast path.
1220
1221 BTW remember: "addr" is allowed to be not aligned
1222 in IP options!
1223 */
1224
1225 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1226 {
1227 __be32 src;
1228
1229 if (rt_is_output_route(rt))
1230 src = ip_hdr(skb)->saddr;
1231 else {
1232 struct fib_result res;
1233 struct flowi4 fl4;
1234 struct iphdr *iph;
1235
1236 iph = ip_hdr(skb);
1237
1238 memset(&fl4, 0, sizeof(fl4));
1239 fl4.daddr = iph->daddr;
1240 fl4.saddr = iph->saddr;
1241 fl4.flowi4_tos = RT_TOS(iph->tos);
1242 fl4.flowi4_oif = rt->dst.dev->ifindex;
1243 fl4.flowi4_iif = skb->dev->ifindex;
1244 fl4.flowi4_mark = skb->mark;
1245
1246 rcu_read_lock();
1247 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1248 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1249 else
1250 src = inet_select_addr(rt->dst.dev,
1251 rt_nexthop(rt, iph->daddr),
1252 RT_SCOPE_UNIVERSE);
1253 rcu_read_unlock();
1254 }
1255 memcpy(addr, &src, 4);
1256 }
1257
1258 #ifdef CONFIG_IP_ROUTE_CLASSID
1259 static void set_class_tag(struct rtable *rt, u32 tag)
1260 {
1261 if (!(rt->dst.tclassid & 0xFFFF))
1262 rt->dst.tclassid |= tag & 0xFFFF;
1263 if (!(rt->dst.tclassid & 0xFFFF0000))
1264 rt->dst.tclassid |= tag & 0xFFFF0000;
1265 }
1266 #endif
1267
1268 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1269 {
1270 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1271 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1272 ip_rt_min_advmss);
1273
1274 return min(advmss, IPV4_MAX_PMTU - header_size);
1275 }
1276
1277 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1278 {
1279 const struct rtable *rt = (const struct rtable *) dst;
1280 unsigned int mtu = rt->rt_pmtu;
1281
1282 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1283 mtu = dst_metric_raw(dst, RTAX_MTU);
1284
1285 if (mtu)
1286 return mtu;
1287
1288 mtu = READ_ONCE(dst->dev->mtu);
1289
1290 if (unlikely(ip_mtu_locked(dst))) {
1291 if (rt->rt_uses_gateway && mtu > 576)
1292 mtu = 576;
1293 }
1294
1295 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1296
1297 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1298 }
1299
1300 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1301 {
1302 struct fnhe_hash_bucket *hash;
1303 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1304 u32 hval = fnhe_hashfun(daddr);
1305
1306 spin_lock_bh(&fnhe_lock);
1307
1308 hash = rcu_dereference_protected(nh->nh_exceptions,
1309 lockdep_is_held(&fnhe_lock));
1310 hash += hval;
1311
1312 fnhe_p = &hash->chain;
1313 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1314 while (fnhe) {
1315 if (fnhe->fnhe_daddr == daddr) {
1316 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1317 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1318 fnhe_flush_routes(fnhe);
1319 kfree_rcu(fnhe, rcu);
1320 break;
1321 }
1322 fnhe_p = &fnhe->fnhe_next;
1323 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1324 lockdep_is_held(&fnhe_lock));
1325 }
1326
1327 spin_unlock_bh(&fnhe_lock);
1328 }
1329
1330 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1331 {
1332 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1333 struct fib_nh_exception *fnhe;
1334 u32 hval;
1335
1336 if (!hash)
1337 return NULL;
1338
1339 hval = fnhe_hashfun(daddr);
1340
1341 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1342 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1343 if (fnhe->fnhe_daddr == daddr) {
1344 if (fnhe->fnhe_expires &&
1345 time_after(jiffies, fnhe->fnhe_expires)) {
1346 ip_del_fnhe(nh, daddr);
1347 break;
1348 }
1349 return fnhe;
1350 }
1351 }
1352 return NULL;
1353 }
1354
1355 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1356 __be32 daddr, const bool do_cache)
1357 {
1358 bool ret = false;
1359
1360 spin_lock_bh(&fnhe_lock);
1361
1362 if (daddr == fnhe->fnhe_daddr) {
1363 struct rtable __rcu **porig;
1364 struct rtable *orig;
1365 int genid = fnhe_genid(dev_net(rt->dst.dev));
1366
1367 if (rt_is_input_route(rt))
1368 porig = &fnhe->fnhe_rth_input;
1369 else
1370 porig = &fnhe->fnhe_rth_output;
1371 orig = rcu_dereference(*porig);
1372
1373 if (fnhe->fnhe_genid != genid) {
1374 fnhe->fnhe_genid = genid;
1375 fnhe->fnhe_gw = 0;
1376 fnhe->fnhe_pmtu = 0;
1377 fnhe->fnhe_expires = 0;
1378 fnhe_flush_routes(fnhe);
1379 orig = NULL;
1380 }
1381 fill_route_from_fnhe(rt, fnhe);
1382 if (!rt->rt_gateway)
1383 rt->rt_gateway = daddr;
1384
1385 if (do_cache) {
1386 dst_hold(&rt->dst);
1387 rcu_assign_pointer(*porig, rt);
1388 if (orig) {
1389 dst_dev_put(&orig->dst);
1390 dst_release(&orig->dst);
1391 }
1392 ret = true;
1393 }
1394
1395 fnhe->fnhe_stamp = jiffies;
1396 }
1397 spin_unlock_bh(&fnhe_lock);
1398
1399 return ret;
1400 }
1401
1402 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1403 {
1404 struct rtable *orig, *prev, **p;
1405 bool ret = true;
1406
1407 if (rt_is_input_route(rt)) {
1408 p = (struct rtable **)&nh->nh_rth_input;
1409 } else {
1410 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1411 }
1412 orig = *p;
1413
1414 /* hold dst before doing cmpxchg() to avoid race condition
1415 * on this dst
1416 */
1417 dst_hold(&rt->dst);
1418 prev = cmpxchg(p, orig, rt);
1419 if (prev == orig) {
1420 if (orig) {
1421 dst_dev_put(&orig->dst);
1422 dst_release(&orig->dst);
1423 }
1424 } else {
1425 dst_release(&rt->dst);
1426 ret = false;
1427 }
1428
1429 return ret;
1430 }
1431
1432 struct uncached_list {
1433 spinlock_t lock;
1434 struct list_head head;
1435 };
1436
1437 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1438
1439 void rt_add_uncached_list(struct rtable *rt)
1440 {
1441 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1442
1443 rt->rt_uncached_list = ul;
1444
1445 spin_lock_bh(&ul->lock);
1446 list_add_tail(&rt->rt_uncached, &ul->head);
1447 spin_unlock_bh(&ul->lock);
1448 }
1449
1450 void rt_del_uncached_list(struct rtable *rt)
1451 {
1452 if (!list_empty(&rt->rt_uncached)) {
1453 struct uncached_list *ul = rt->rt_uncached_list;
1454
1455 spin_lock_bh(&ul->lock);
1456 list_del(&rt->rt_uncached);
1457 spin_unlock_bh(&ul->lock);
1458 }
1459 }
1460
1461 static void ipv4_dst_destroy(struct dst_entry *dst)
1462 {
1463 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1464 struct rtable *rt = (struct rtable *)dst;
1465
1466 if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
1467 kfree(p);
1468
1469 rt_del_uncached_list(rt);
1470 }
1471
1472 void rt_flush_dev(struct net_device *dev)
1473 {
1474 struct net *net = dev_net(dev);
1475 struct rtable *rt;
1476 int cpu;
1477
1478 for_each_possible_cpu(cpu) {
1479 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1480
1481 spin_lock_bh(&ul->lock);
1482 list_for_each_entry(rt, &ul->head, rt_uncached) {
1483 if (rt->dst.dev != dev)
1484 continue;
1485 rt->dst.dev = net->loopback_dev;
1486 dev_hold(rt->dst.dev);
1487 dev_put(dev);
1488 }
1489 spin_unlock_bh(&ul->lock);
1490 }
1491 }
1492
1493 static bool rt_cache_valid(const struct rtable *rt)
1494 {
1495 return rt &&
1496 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1497 !rt_is_expired(rt);
1498 }
1499
1500 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1501 const struct fib_result *res,
1502 struct fib_nh_exception *fnhe,
1503 struct fib_info *fi, u16 type, u32 itag,
1504 const bool do_cache)
1505 {
1506 bool cached = false;
1507
1508 if (fi) {
1509 struct fib_nh *nh = &FIB_RES_NH(*res);
1510
1511 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1512 rt->rt_gateway = nh->nh_gw;
1513 rt->rt_uses_gateway = 1;
1514 }
1515 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1516 if (fi->fib_metrics != &dst_default_metrics) {
1517 rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1518 refcount_inc(&fi->fib_metrics->refcnt);
1519 }
1520 #ifdef CONFIG_IP_ROUTE_CLASSID
1521 rt->dst.tclassid = nh->nh_tclassid;
1522 #endif
1523 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1524 if (unlikely(fnhe))
1525 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1526 else if (do_cache)
1527 cached = rt_cache_route(nh, rt);
1528 if (unlikely(!cached)) {
1529 /* Routes we intend to cache in nexthop exception or
1530 * FIB nexthop have the DST_NOCACHE bit clear.
1531 * However, if we are unsuccessful at storing this
1532 * route into the cache we really need to set it.
1533 */
1534 if (!rt->rt_gateway)
1535 rt->rt_gateway = daddr;
1536 rt_add_uncached_list(rt);
1537 }
1538 } else
1539 rt_add_uncached_list(rt);
1540
1541 #ifdef CONFIG_IP_ROUTE_CLASSID
1542 #ifdef CONFIG_IP_MULTIPLE_TABLES
1543 set_class_tag(rt, res->tclassid);
1544 #endif
1545 set_class_tag(rt, itag);
1546 #endif
1547 }
1548
1549 struct rtable *rt_dst_alloc(struct net_device *dev,
1550 unsigned int flags, u16 type,
1551 bool nopolicy, bool noxfrm, bool will_cache)
1552 {
1553 struct rtable *rt;
1554
1555 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1556 (will_cache ? 0 : DST_HOST) |
1557 (nopolicy ? DST_NOPOLICY : 0) |
1558 (noxfrm ? DST_NOXFRM : 0));
1559
1560 if (rt) {
1561 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1562 rt->rt_flags = flags;
1563 rt->rt_type = type;
1564 rt->rt_is_input = 0;
1565 rt->rt_iif = 0;
1566 rt->rt_pmtu = 0;
1567 rt->rt_mtu_locked = 0;
1568 rt->rt_gateway = 0;
1569 rt->rt_uses_gateway = 0;
1570 INIT_LIST_HEAD(&rt->rt_uncached);
1571
1572 rt->dst.output = ip_output;
1573 if (flags & RTCF_LOCAL)
1574 rt->dst.input = ip_local_deliver;
1575 }
1576
1577 return rt;
1578 }
1579 EXPORT_SYMBOL(rt_dst_alloc);
1580
1581 /* called in rcu_read_lock() section */
1582 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1583 u8 tos, struct net_device *dev,
1584 struct in_device *in_dev, u32 *itag)
1585 {
1586 int err;
1587
1588 /* Primary sanity checks. */
1589 if (!in_dev)
1590 return -EINVAL;
1591
1592 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1593 skb->protocol != htons(ETH_P_IP))
1594 return -EINVAL;
1595
1596 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1597 return -EINVAL;
1598
1599 if (ipv4_is_zeronet(saddr)) {
1600 if (!ipv4_is_local_multicast(daddr))
1601 return -EINVAL;
1602 } else {
1603 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1604 in_dev, itag);
1605 if (err < 0)
1606 return err;
1607 }
1608 return 0;
1609 }
1610
1611 /* called in rcu_read_lock() section */
1612 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1613 u8 tos, struct net_device *dev, int our)
1614 {
1615 struct in_device *in_dev = __in_dev_get_rcu(dev);
1616 unsigned int flags = RTCF_MULTICAST;
1617 struct rtable *rth;
1618 u32 itag = 0;
1619 int err;
1620
1621 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1622 if (err)
1623 return err;
1624
1625 if (our)
1626 flags |= RTCF_LOCAL;
1627
1628 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1629 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1630 if (!rth)
1631 return -ENOBUFS;
1632
1633 #ifdef CONFIG_IP_ROUTE_CLASSID
1634 rth->dst.tclassid = itag;
1635 #endif
1636 rth->dst.output = ip_rt_bug;
1637 rth->rt_is_input= 1;
1638
1639 #ifdef CONFIG_IP_MROUTE
1640 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1641 rth->dst.input = ip_mr_input;
1642 #endif
1643 RT_CACHE_STAT_INC(in_slow_mc);
1644
1645 skb_dst_set(skb, &rth->dst);
1646 return 0;
1647 }
1648
1649
1650 static void ip_handle_martian_source(struct net_device *dev,
1651 struct in_device *in_dev,
1652 struct sk_buff *skb,
1653 __be32 daddr,
1654 __be32 saddr)
1655 {
1656 RT_CACHE_STAT_INC(in_martian_src);
1657 #ifdef CONFIG_IP_ROUTE_VERBOSE
1658 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1659 /*
1660 * RFC1812 recommendation, if source is martian,
1661 * the only hint is MAC header.
1662 */
1663 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1664 &daddr, &saddr, dev->name);
1665 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1666 print_hex_dump(KERN_WARNING, "ll header: ",
1667 DUMP_PREFIX_OFFSET, 16, 1,
1668 skb_mac_header(skb),
1669 dev->hard_header_len, true);
1670 }
1671 }
1672 #endif
1673 }
1674
1675 /* called in rcu_read_lock() section */
1676 static int __mkroute_input(struct sk_buff *skb,
1677 const struct fib_result *res,
1678 struct in_device *in_dev,
1679 __be32 daddr, __be32 saddr, u32 tos)
1680 {
1681 struct fib_nh_exception *fnhe;
1682 struct rtable *rth;
1683 int err;
1684 struct in_device *out_dev;
1685 bool do_cache;
1686 u32 itag = 0;
1687
1688 /* get a working reference to the output device */
1689 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1690 if (!out_dev) {
1691 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1692 return -EINVAL;
1693 }
1694
1695 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1696 in_dev->dev, in_dev, &itag);
1697 if (err < 0) {
1698 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1699 saddr);
1700
1701 goto cleanup;
1702 }
1703
1704 do_cache = res->fi && !itag;
1705 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1706 skb->protocol == htons(ETH_P_IP) &&
1707 (IN_DEV_SHARED_MEDIA(out_dev) ||
1708 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1709 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1710
1711 if (skb->protocol != htons(ETH_P_IP)) {
1712 /* Not IP (i.e. ARP). Do not create route, if it is
1713 * invalid for proxy arp. DNAT routes are always valid.
1714 *
1715 * Proxy arp feature have been extended to allow, ARP
1716 * replies back to the same interface, to support
1717 * Private VLAN switch technologies. See arp.c.
1718 */
1719 if (out_dev == in_dev &&
1720 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1721 err = -EINVAL;
1722 goto cleanup;
1723 }
1724 }
1725
1726 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1727 if (do_cache) {
1728 if (fnhe)
1729 rth = rcu_dereference(fnhe->fnhe_rth_input);
1730 else
1731 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1732 if (rt_cache_valid(rth)) {
1733 skb_dst_set_noref(skb, &rth->dst);
1734 goto out;
1735 }
1736 }
1737
1738 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1739 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1740 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1741 if (!rth) {
1742 err = -ENOBUFS;
1743 goto cleanup;
1744 }
1745
1746 rth->rt_is_input = 1;
1747 RT_CACHE_STAT_INC(in_slow_tot);
1748
1749 rth->dst.input = ip_forward;
1750
1751 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1752 do_cache);
1753 lwtunnel_set_redirect(&rth->dst);
1754 skb_dst_set(skb, &rth->dst);
1755 out:
1756 err = 0;
1757 cleanup:
1758 return err;
1759 }
1760
1761 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1762 /* To make ICMP packets follow the right flow, the multipath hash is
1763 * calculated from the inner IP addresses.
1764 */
1765 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1766 struct flow_keys *hash_keys)
1767 {
1768 const struct iphdr *outer_iph = ip_hdr(skb);
1769 const struct iphdr *key_iph = outer_iph;
1770 const struct iphdr *inner_iph;
1771 const struct icmphdr *icmph;
1772 struct iphdr _inner_iph;
1773 struct icmphdr _icmph;
1774
1775 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1776 goto out;
1777
1778 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1779 goto out;
1780
1781 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1782 &_icmph);
1783 if (!icmph)
1784 goto out;
1785
1786 if (icmph->type != ICMP_DEST_UNREACH &&
1787 icmph->type != ICMP_REDIRECT &&
1788 icmph->type != ICMP_TIME_EXCEEDED &&
1789 icmph->type != ICMP_PARAMETERPROB)
1790 goto out;
1791
1792 inner_iph = skb_header_pointer(skb,
1793 outer_iph->ihl * 4 + sizeof(_icmph),
1794 sizeof(_inner_iph), &_inner_iph);
1795 if (!inner_iph)
1796 goto out;
1797
1798 key_iph = inner_iph;
1799 out:
1800 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1801 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1802 }
1803
1804 /* if skb is set it will be used and fl4 can be NULL */
1805 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1806 const struct sk_buff *skb, struct flow_keys *flkeys)
1807 {
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
1832 memset(&hash_keys, 0, sizeof(hash_keys));
1833
1834 if (!flkeys) {
1835 skb_flow_dissect_flow_keys(skb, &keys, flag);
1836 flkeys = &keys;
1837 }
1838
1839 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1840 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1841 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1842 hash_keys.ports.src = flkeys->ports.src;
1843 hash_keys.ports.dst = flkeys->ports.dst;
1844 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1845 } else {
1846 memset(&hash_keys, 0, sizeof(hash_keys));
1847 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1848 hash_keys.addrs.v4addrs.src = fl4->saddr;
1849 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1850 hash_keys.ports.src = fl4->fl4_sport;
1851 hash_keys.ports.dst = fl4->fl4_dport;
1852 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1853 }
1854 break;
1855 }
1856 mhash = flow_hash_from_keys(&hash_keys);
1857
1858 return mhash >> 1;
1859 }
1860 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
1861
1862 static int ip_mkroute_input(struct sk_buff *skb,
1863 struct fib_result *res,
1864 struct in_device *in_dev,
1865 __be32 daddr, __be32 saddr, u32 tos,
1866 struct flow_keys *hkeys)
1867 {
1868 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1869 if (res->fi && res->fi->fib_nhs > 1) {
1870 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
1871
1872 fib_select_multipath(res, h);
1873 }
1874 #endif
1875
1876 /* create a routing cache entry */
1877 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1878 }
1879
1880 /*
1881 * NOTE. We drop all the packets that has local source
1882 * addresses, because every properly looped back packet
1883 * must have correct destination already attached by output routine.
1884 *
1885 * Such approach solves two big problems:
1886 * 1. Not simplex devices are handled properly.
1887 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1888 * called with rcu_read_lock()
1889 */
1890
1891 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1892 u8 tos, struct net_device *dev,
1893 struct fib_result *res)
1894 {
1895 struct in_device *in_dev = __in_dev_get_rcu(dev);
1896 struct flow_keys *flkeys = NULL, _flkeys;
1897 struct net *net = dev_net(dev);
1898 struct ip_tunnel_info *tun_info;
1899 int err = -EINVAL;
1900 unsigned int flags = 0;
1901 u32 itag = 0;
1902 struct rtable *rth;
1903 struct flowi4 fl4;
1904 bool do_cache;
1905
1906 /* IP on this device is disabled. */
1907
1908 if (!in_dev)
1909 goto out;
1910
1911 /* Check for the most weird martians, which can be not detected
1912 by fib_lookup.
1913 */
1914
1915 tun_info = skb_tunnel_info(skb);
1916 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1917 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1918 else
1919 fl4.flowi4_tun_key.tun_id = 0;
1920 skb_dst_drop(skb);
1921
1922 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1923 goto martian_source;
1924
1925 res->fi = NULL;
1926 res->table = NULL;
1927 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1928 goto brd_input;
1929
1930 /* Accept zero addresses only to limited broadcast;
1931 * I even do not know to fix it or not. Waiting for complains :-)
1932 */
1933 if (ipv4_is_zeronet(saddr))
1934 goto martian_source;
1935
1936 if (ipv4_is_zeronet(daddr))
1937 goto martian_destination;
1938
1939 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1940 * and call it once if daddr or/and saddr are loopback addresses
1941 */
1942 if (ipv4_is_loopback(daddr)) {
1943 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1944 goto martian_destination;
1945 } else if (ipv4_is_loopback(saddr)) {
1946 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1947 goto martian_source;
1948 }
1949
1950 /*
1951 * Now we are ready to route packet.
1952 */
1953 fl4.flowi4_oif = 0;
1954 fl4.flowi4_iif = dev->ifindex;
1955 fl4.flowi4_mark = skb->mark;
1956 fl4.flowi4_tos = tos;
1957 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1958 fl4.flowi4_flags = 0;
1959 fl4.daddr = daddr;
1960 fl4.saddr = saddr;
1961 fl4.flowi4_uid = sock_net_uid(net, NULL);
1962
1963 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys))
1964 flkeys = &_flkeys;
1965
1966 err = fib_lookup(net, &fl4, res, 0);
1967 if (err != 0) {
1968 if (!IN_DEV_FORWARD(in_dev))
1969 err = -EHOSTUNREACH;
1970 goto no_route;
1971 }
1972
1973 if (res->type == RTN_BROADCAST)
1974 goto brd_input;
1975
1976 if (res->type == RTN_LOCAL) {
1977 err = fib_validate_source(skb, saddr, daddr, tos,
1978 0, dev, in_dev, &itag);
1979 if (err < 0)
1980 goto martian_source;
1981 goto local_input;
1982 }
1983
1984 if (!IN_DEV_FORWARD(in_dev)) {
1985 err = -EHOSTUNREACH;
1986 goto no_route;
1987 }
1988 if (res->type != RTN_UNICAST)
1989 goto martian_destination;
1990
1991 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
1992 out: return err;
1993
1994 brd_input:
1995 if (skb->protocol != htons(ETH_P_IP))
1996 goto e_inval;
1997
1998 if (!ipv4_is_zeronet(saddr)) {
1999 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2000 in_dev, &itag);
2001 if (err < 0)
2002 goto martian_source;
2003 }
2004 flags |= RTCF_BROADCAST;
2005 res->type = RTN_BROADCAST;
2006 RT_CACHE_STAT_INC(in_brd);
2007
2008 local_input:
2009 do_cache = false;
2010 if (res->fi) {
2011 if (!itag) {
2012 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
2013 if (rt_cache_valid(rth)) {
2014 skb_dst_set_noref(skb, &rth->dst);
2015 err = 0;
2016 goto out;
2017 }
2018 do_cache = true;
2019 }
2020 }
2021
2022 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2023 flags | RTCF_LOCAL, res->type,
2024 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2025 if (!rth)
2026 goto e_nobufs;
2027
2028 rth->dst.output= ip_rt_bug;
2029 #ifdef CONFIG_IP_ROUTE_CLASSID
2030 rth->dst.tclassid = itag;
2031 #endif
2032 rth->rt_is_input = 1;
2033
2034 RT_CACHE_STAT_INC(in_slow_tot);
2035 if (res->type == RTN_UNREACHABLE) {
2036 rth->dst.input= ip_error;
2037 rth->dst.error= -err;
2038 rth->rt_flags &= ~RTCF_LOCAL;
2039 }
2040
2041 if (do_cache) {
2042 struct fib_nh *nh = &FIB_RES_NH(*res);
2043
2044 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2045 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2046 WARN_ON(rth->dst.input == lwtunnel_input);
2047 rth->dst.lwtstate->orig_input = rth->dst.input;
2048 rth->dst.input = lwtunnel_input;
2049 }
2050
2051 if (unlikely(!rt_cache_route(nh, rth)))
2052 rt_add_uncached_list(rth);
2053 }
2054 skb_dst_set(skb, &rth->dst);
2055 err = 0;
2056 goto out;
2057
2058 no_route:
2059 RT_CACHE_STAT_INC(in_no_route);
2060 res->type = RTN_UNREACHABLE;
2061 res->fi = NULL;
2062 res->table = NULL;
2063 goto local_input;
2064
2065 /*
2066 * Do not cache martian addresses: they should be logged (RFC1812)
2067 */
2068 martian_destination:
2069 RT_CACHE_STAT_INC(in_martian_dst);
2070 #ifdef CONFIG_IP_ROUTE_VERBOSE
2071 if (IN_DEV_LOG_MARTIANS(in_dev))
2072 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2073 &daddr, &saddr, dev->name);
2074 #endif
2075
2076 e_inval:
2077 err = -EINVAL;
2078 goto out;
2079
2080 e_nobufs:
2081 err = -ENOBUFS;
2082 goto out;
2083
2084 martian_source:
2085 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2086 goto out;
2087 }
2088
2089 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2090 u8 tos, struct net_device *dev)
2091 {
2092 struct fib_result res;
2093 int err;
2094
2095 tos &= IPTOS_RT_MASK;
2096 rcu_read_lock();
2097 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2098 rcu_read_unlock();
2099
2100 return err;
2101 }
2102 EXPORT_SYMBOL(ip_route_input_noref);
2103
2104 /* called with rcu_read_lock held */
2105 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2106 u8 tos, struct net_device *dev, struct fib_result *res)
2107 {
2108 /* Multicast recognition logic is moved from route cache to here.
2109 The problem was that too many Ethernet cards have broken/missing
2110 hardware multicast filters :-( As result the host on multicasting
2111 network acquires a lot of useless route cache entries, sort of
2112 SDR messages from all the world. Now we try to get rid of them.
2113 Really, provided software IP multicast filter is organized
2114 reasonably (at least, hashed), it does not result in a slowdown
2115 comparing with route cache reject entries.
2116 Note, that multicast routers are not affected, because
2117 route cache entry is created eventually.
2118 */
2119 if (ipv4_is_multicast(daddr)) {
2120 struct in_device *in_dev = __in_dev_get_rcu(dev);
2121 int our = 0;
2122 int err = -EINVAL;
2123
2124 if (in_dev)
2125 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2126 ip_hdr(skb)->protocol);
2127
2128 /* check l3 master if no match yet */
2129 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2130 struct in_device *l3_in_dev;
2131
2132 l3_in_dev = __in_dev_get_rcu(skb->dev);
2133 if (l3_in_dev)
2134 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2135 ip_hdr(skb)->protocol);
2136 }
2137
2138 if (our
2139 #ifdef CONFIG_IP_MROUTE
2140 ||
2141 (!ipv4_is_local_multicast(daddr) &&
2142 IN_DEV_MFORWARD(in_dev))
2143 #endif
2144 ) {
2145 err = ip_route_input_mc(skb, daddr, saddr,
2146 tos, dev, our);
2147 }
2148 return err;
2149 }
2150
2151 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2152 }
2153
2154 /* called with rcu_read_lock() */
2155 static struct rtable *__mkroute_output(const struct fib_result *res,
2156 const struct flowi4 *fl4, int orig_oif,
2157 struct net_device *dev_out,
2158 unsigned int flags)
2159 {
2160 struct fib_info *fi = res->fi;
2161 struct fib_nh_exception *fnhe;
2162 struct in_device *in_dev;
2163 u16 type = res->type;
2164 struct rtable *rth;
2165 bool do_cache;
2166
2167 in_dev = __in_dev_get_rcu(dev_out);
2168 if (!in_dev)
2169 return ERR_PTR(-EINVAL);
2170
2171 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2172 if (ipv4_is_loopback(fl4->saddr) &&
2173 !(dev_out->flags & IFF_LOOPBACK) &&
2174 !netif_is_l3_master(dev_out))
2175 return ERR_PTR(-EINVAL);
2176
2177 if (ipv4_is_lbcast(fl4->daddr))
2178 type = RTN_BROADCAST;
2179 else if (ipv4_is_multicast(fl4->daddr))
2180 type = RTN_MULTICAST;
2181 else if (ipv4_is_zeronet(fl4->daddr))
2182 return ERR_PTR(-EINVAL);
2183
2184 if (dev_out->flags & IFF_LOOPBACK)
2185 flags |= RTCF_LOCAL;
2186
2187 do_cache = true;
2188 if (type == RTN_BROADCAST) {
2189 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2190 fi = NULL;
2191 } else if (type == RTN_MULTICAST) {
2192 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2193 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2194 fl4->flowi4_proto))
2195 flags &= ~RTCF_LOCAL;
2196 else
2197 do_cache = false;
2198 /* If multicast route do not exist use
2199 * default one, but do not gateway in this case.
2200 * Yes, it is hack.
2201 */
2202 if (fi && res->prefixlen < 4)
2203 fi = NULL;
2204 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2205 (orig_oif != dev_out->ifindex)) {
2206 /* For local routes that require a particular output interface
2207 * we do not want to cache the result. Caching the result
2208 * causes incorrect behaviour when there are multiple source
2209 * addresses on the interface, the end result being that if the
2210 * intended recipient is waiting on that interface for the
2211 * packet he won't receive it because it will be delivered on
2212 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2213 * be set to the loopback interface as well.
2214 */
2215 do_cache = false;
2216 }
2217
2218 fnhe = NULL;
2219 do_cache &= fi != NULL;
2220 if (fi) {
2221 struct rtable __rcu **prth;
2222 struct fib_nh *nh = &FIB_RES_NH(*res);
2223
2224 fnhe = find_exception(nh, fl4->daddr);
2225 if (!do_cache)
2226 goto add;
2227 if (fnhe) {
2228 prth = &fnhe->fnhe_rth_output;
2229 } else {
2230 if (unlikely(fl4->flowi4_flags &
2231 FLOWI_FLAG_KNOWN_NH &&
2232 !(nh->nh_gw &&
2233 nh->nh_scope == RT_SCOPE_LINK))) {
2234 do_cache = false;
2235 goto add;
2236 }
2237 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2238 }
2239 rth = rcu_dereference(*prth);
2240 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2241 return rth;
2242 }
2243
2244 add:
2245 rth = rt_dst_alloc(dev_out, flags, type,
2246 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2247 IN_DEV_CONF_GET(in_dev, NOXFRM),
2248 do_cache);
2249 if (!rth)
2250 return ERR_PTR(-ENOBUFS);
2251
2252 rth->rt_iif = orig_oif;
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 lwtunnel_set_redirect(&rth->dst);
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 .type = RTN_UNSPEC,
2289 .fi = NULL,
2290 .table = NULL,
2291 .tclassid = 0,
2292 };
2293 struct rtable *rth;
2294
2295 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2296 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2297 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2298 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2299
2300 rcu_read_lock();
2301 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2302 rcu_read_unlock();
2303
2304 return rth;
2305 }
2306 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2307
2308 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2309 struct fib_result *res,
2310 const struct sk_buff *skb)
2311 {
2312 struct net_device *dev_out = NULL;
2313 int orig_oif = fl4->flowi4_oif;
2314 unsigned int flags = 0;
2315 struct rtable *rth;
2316 int err = -ENETUNREACH;
2317
2318 if (fl4->saddr) {
2319 rth = ERR_PTR(-EINVAL);
2320 if (ipv4_is_multicast(fl4->saddr) ||
2321 ipv4_is_lbcast(fl4->saddr) ||
2322 ipv4_is_zeronet(fl4->saddr))
2323 goto out;
2324
2325 /* I removed check for oif == dev_out->oif here.
2326 It was wrong for two reasons:
2327 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2328 is assigned to multiple interfaces.
2329 2. Moreover, we are allowed to send packets with saddr
2330 of another iface. --ANK
2331 */
2332
2333 if (fl4->flowi4_oif == 0 &&
2334 (ipv4_is_multicast(fl4->daddr) ||
2335 ipv4_is_lbcast(fl4->daddr))) {
2336 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2337 dev_out = __ip_dev_find(net, fl4->saddr, false);
2338 if (!dev_out)
2339 goto out;
2340
2341 /* Special hack: user can direct multicasts
2342 and limited broadcast via necessary interface
2343 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2344 This hack is not just for fun, it allows
2345 vic,vat and friends to work.
2346 They bind socket to loopback, set ttl to zero
2347 and expect that it will work.
2348 From the viewpoint of routing cache they are broken,
2349 because we are not allowed to build multicast path
2350 with loopback source addr (look, routing cache
2351 cannot know, that ttl is zero, so that packet
2352 will not leave this host and route is valid).
2353 Luckily, this hack is good workaround.
2354 */
2355
2356 fl4->flowi4_oif = dev_out->ifindex;
2357 goto make_route;
2358 }
2359
2360 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2361 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2362 if (!__ip_dev_find(net, fl4->saddr, false))
2363 goto out;
2364 }
2365 }
2366
2367
2368 if (fl4->flowi4_oif) {
2369 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2370 rth = ERR_PTR(-ENODEV);
2371 if (!dev_out)
2372 goto out;
2373
2374 /* RACE: Check return value of inet_select_addr instead. */
2375 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2376 rth = ERR_PTR(-ENETUNREACH);
2377 goto out;
2378 }
2379 if (ipv4_is_local_multicast(fl4->daddr) ||
2380 ipv4_is_lbcast(fl4->daddr) ||
2381 fl4->flowi4_proto == IPPROTO_IGMP) {
2382 if (!fl4->saddr)
2383 fl4->saddr = inet_select_addr(dev_out, 0,
2384 RT_SCOPE_LINK);
2385 goto make_route;
2386 }
2387 if (!fl4->saddr) {
2388 if (ipv4_is_multicast(fl4->daddr))
2389 fl4->saddr = inet_select_addr(dev_out, 0,
2390 fl4->flowi4_scope);
2391 else if (!fl4->daddr)
2392 fl4->saddr = inet_select_addr(dev_out, 0,
2393 RT_SCOPE_HOST);
2394 }
2395 }
2396
2397 if (!fl4->daddr) {
2398 fl4->daddr = fl4->saddr;
2399 if (!fl4->daddr)
2400 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2401 dev_out = net->loopback_dev;
2402 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2403 res->type = RTN_LOCAL;
2404 flags |= RTCF_LOCAL;
2405 goto make_route;
2406 }
2407
2408 err = fib_lookup(net, fl4, res, 0);
2409 if (err) {
2410 res->fi = NULL;
2411 res->table = NULL;
2412 if (fl4->flowi4_oif &&
2413 (ipv4_is_multicast(fl4->daddr) ||
2414 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2415 /* Apparently, routing tables are wrong. Assume,
2416 that the destination is on link.
2417
2418 WHY? DW.
2419 Because we are allowed to send to iface
2420 even if it has NO routes and NO assigned
2421 addresses. When oif is specified, routing
2422 tables are looked up with only one purpose:
2423 to catch if destination is gatewayed, rather than
2424 direct. Moreover, if MSG_DONTROUTE is set,
2425 we send packet, ignoring both routing tables
2426 and ifaddr state. --ANK
2427
2428
2429 We could make it even if oif is unknown,
2430 likely IPv6, but we do not.
2431 */
2432
2433 if (fl4->saddr == 0)
2434 fl4->saddr = inet_select_addr(dev_out, 0,
2435 RT_SCOPE_LINK);
2436 res->type = RTN_UNICAST;
2437 goto make_route;
2438 }
2439 rth = ERR_PTR(err);
2440 goto out;
2441 }
2442
2443 if (res->type == RTN_LOCAL) {
2444 if (!fl4->saddr) {
2445 if (res->fi->fib_prefsrc)
2446 fl4->saddr = res->fi->fib_prefsrc;
2447 else
2448 fl4->saddr = fl4->daddr;
2449 }
2450
2451 /* L3 master device is the loopback for that domain */
2452 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2453 net->loopback_dev;
2454
2455 /* make sure orig_oif points to fib result device even
2456 * though packet rx/tx happens over loopback or l3mdev
2457 */
2458 orig_oif = FIB_RES_OIF(*res);
2459
2460 fl4->flowi4_oif = dev_out->ifindex;
2461 flags |= RTCF_LOCAL;
2462 goto make_route;
2463 }
2464
2465 fib_select_path(net, res, fl4, skb);
2466
2467 dev_out = FIB_RES_DEV(*res);
2468 fl4->flowi4_oif = dev_out->ifindex;
2469
2470
2471 make_route:
2472 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2473
2474 out:
2475 return rth;
2476 }
2477
2478 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2479 {
2480 return NULL;
2481 }
2482
2483 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2484 {
2485 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2486
2487 return mtu ? : dst->dev->mtu;
2488 }
2489
2490 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2491 struct sk_buff *skb, u32 mtu)
2492 {
2493 }
2494
2495 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2496 struct sk_buff *skb)
2497 {
2498 }
2499
2500 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2501 unsigned long old)
2502 {
2503 return NULL;
2504 }
2505
2506 static struct dst_ops ipv4_dst_blackhole_ops = {
2507 .family = AF_INET,
2508 .check = ipv4_blackhole_dst_check,
2509 .mtu = ipv4_blackhole_mtu,
2510 .default_advmss = ipv4_default_advmss,
2511 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2512 .redirect = ipv4_rt_blackhole_redirect,
2513 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2514 .neigh_lookup = ipv4_neigh_lookup,
2515 };
2516
2517 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2518 {
2519 struct rtable *ort = (struct rtable *) dst_orig;
2520 struct rtable *rt;
2521
2522 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2523 if (rt) {
2524 struct dst_entry *new = &rt->dst;
2525
2526 new->__use = 1;
2527 new->input = dst_discard;
2528 new->output = dst_discard_out;
2529
2530 new->dev = net->loopback_dev;
2531 if (new->dev)
2532 dev_hold(new->dev);
2533
2534 rt->rt_is_input = ort->rt_is_input;
2535 rt->rt_iif = ort->rt_iif;
2536 rt->rt_pmtu = ort->rt_pmtu;
2537 rt->rt_mtu_locked = ort->rt_mtu_locked;
2538
2539 rt->rt_genid = rt_genid_ipv4(net);
2540 rt->rt_flags = ort->rt_flags;
2541 rt->rt_type = ort->rt_type;
2542 rt->rt_gateway = ort->rt_gateway;
2543 rt->rt_uses_gateway = ort->rt_uses_gateway;
2544
2545 INIT_LIST_HEAD(&rt->rt_uncached);
2546 }
2547
2548 dst_release(dst_orig);
2549
2550 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2551 }
2552
2553 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2554 const struct sock *sk)
2555 {
2556 struct rtable *rt = __ip_route_output_key(net, flp4);
2557
2558 if (IS_ERR(rt))
2559 return rt;
2560
2561 if (flp4->flowi4_proto)
2562 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2563 flowi4_to_flowi(flp4),
2564 sk, 0);
2565
2566 return rt;
2567 }
2568 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2569
2570 /* called with rcu_read_lock held */
2571 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2572 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2573 u32 seq)
2574 {
2575 struct rtable *rt = skb_rtable(skb);
2576 struct rtmsg *r;
2577 struct nlmsghdr *nlh;
2578 unsigned long expires = 0;
2579 u32 error;
2580 u32 metrics[RTAX_MAX];
2581
2582 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2583 if (!nlh)
2584 return -EMSGSIZE;
2585
2586 r = nlmsg_data(nlh);
2587 r->rtm_family = AF_INET;
2588 r->rtm_dst_len = 32;
2589 r->rtm_src_len = 0;
2590 r->rtm_tos = fl4->flowi4_tos;
2591 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2592 if (nla_put_u32(skb, RTA_TABLE, table_id))
2593 goto nla_put_failure;
2594 r->rtm_type = rt->rt_type;
2595 r->rtm_scope = RT_SCOPE_UNIVERSE;
2596 r->rtm_protocol = RTPROT_UNSPEC;
2597 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2598 if (rt->rt_flags & RTCF_NOTIFY)
2599 r->rtm_flags |= RTM_F_NOTIFY;
2600 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2601 r->rtm_flags |= RTCF_DOREDIRECT;
2602
2603 if (nla_put_in_addr(skb, RTA_DST, dst))
2604 goto nla_put_failure;
2605 if (src) {
2606 r->rtm_src_len = 32;
2607 if (nla_put_in_addr(skb, RTA_SRC, src))
2608 goto nla_put_failure;
2609 }
2610 if (rt->dst.dev &&
2611 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2612 goto nla_put_failure;
2613 #ifdef CONFIG_IP_ROUTE_CLASSID
2614 if (rt->dst.tclassid &&
2615 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2616 goto nla_put_failure;
2617 #endif
2618 if (!rt_is_input_route(rt) &&
2619 fl4->saddr != src) {
2620 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2621 goto nla_put_failure;
2622 }
2623 if (rt->rt_uses_gateway &&
2624 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2625 goto nla_put_failure;
2626
2627 expires = rt->dst.expires;
2628 if (expires) {
2629 unsigned long now = jiffies;
2630
2631 if (time_before(now, expires))
2632 expires -= now;
2633 else
2634 expires = 0;
2635 }
2636
2637 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2638 if (rt->rt_pmtu && expires)
2639 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2640 if (rt->rt_mtu_locked && expires)
2641 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2642 if (rtnetlink_put_metrics(skb, metrics) < 0)
2643 goto nla_put_failure;
2644
2645 if (fl4->flowi4_mark &&
2646 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2647 goto nla_put_failure;
2648
2649 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2650 nla_put_u32(skb, RTA_UID,
2651 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2652 goto nla_put_failure;
2653
2654 error = rt->dst.error;
2655
2656 if (rt_is_input_route(rt)) {
2657 #ifdef CONFIG_IP_MROUTE
2658 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2659 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2660 int err = ipmr_get_route(net, skb,
2661 fl4->saddr, fl4->daddr,
2662 r, portid);
2663
2664 if (err <= 0) {
2665 if (err == 0)
2666 return 0;
2667 goto nla_put_failure;
2668 }
2669 } else
2670 #endif
2671 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2672 goto nla_put_failure;
2673 }
2674
2675 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2676 goto nla_put_failure;
2677
2678 nlmsg_end(skb, nlh);
2679 return 0;
2680
2681 nla_put_failure:
2682 nlmsg_cancel(skb, nlh);
2683 return -EMSGSIZE;
2684 }
2685
2686 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2687 struct netlink_ext_ack *extack)
2688 {
2689 struct net *net = sock_net(in_skb->sk);
2690 struct rtmsg *rtm;
2691 struct nlattr *tb[RTA_MAX+1];
2692 struct fib_result res = {};
2693 struct rtable *rt = NULL;
2694 struct flowi4 fl4;
2695 __be32 dst = 0;
2696 __be32 src = 0;
2697 u32 iif;
2698 int err;
2699 int mark;
2700 struct sk_buff *skb;
2701 u32 table_id = RT_TABLE_MAIN;
2702 kuid_t uid;
2703
2704 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2705 extack);
2706 if (err < 0)
2707 goto errout;
2708
2709 rtm = nlmsg_data(nlh);
2710
2711 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2712 if (!skb) {
2713 err = -ENOBUFS;
2714 goto errout;
2715 }
2716
2717 /* Reserve room for dummy headers, this skb can pass
2718 through good chunk of routing engine.
2719 */
2720 skb_reset_mac_header(skb);
2721 skb_reset_network_header(skb);
2722
2723 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2724 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2725 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2726 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2727 if (tb[RTA_UID])
2728 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2729 else
2730 uid = (iif ? INVALID_UID : current_uid());
2731
2732 /* Bugfix: need to give ip_route_input enough of an IP header to
2733 * not gag.
2734 */
2735 ip_hdr(skb)->protocol = IPPROTO_UDP;
2736 ip_hdr(skb)->saddr = src;
2737 ip_hdr(skb)->daddr = dst;
2738
2739 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2740
2741 memset(&fl4, 0, sizeof(fl4));
2742 fl4.daddr = dst;
2743 fl4.saddr = src;
2744 fl4.flowi4_tos = rtm->rtm_tos;
2745 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2746 fl4.flowi4_mark = mark;
2747 fl4.flowi4_uid = uid;
2748
2749 rcu_read_lock();
2750
2751 if (iif) {
2752 struct net_device *dev;
2753
2754 dev = dev_get_by_index_rcu(net, iif);
2755 if (!dev) {
2756 err = -ENODEV;
2757 goto errout_free;
2758 }
2759
2760 skb->protocol = htons(ETH_P_IP);
2761 skb->dev = dev;
2762 skb->mark = mark;
2763 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
2764 dev, &res);
2765
2766 rt = skb_rtable(skb);
2767 if (err == 0 && rt->dst.error)
2768 err = -rt->dst.error;
2769 } else {
2770 fl4.flowi4_iif = LOOPBACK_IFINDEX;
2771 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
2772 err = 0;
2773 if (IS_ERR(rt))
2774 err = PTR_ERR(rt);
2775 else
2776 skb_dst_set(skb, &rt->dst);
2777 }
2778
2779 if (err)
2780 goto errout_free;
2781
2782 if (rtm->rtm_flags & RTM_F_NOTIFY)
2783 rt->rt_flags |= RTCF_NOTIFY;
2784
2785 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2786 table_id = res.table ? res.table->tb_id : 0;
2787
2788 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2789 if (!res.fi) {
2790 err = fib_props[res.type].error;
2791 if (!err)
2792 err = -EHOSTUNREACH;
2793 goto errout_free;
2794 }
2795 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
2796 nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
2797 rt->rt_type, res.prefix, res.prefixlen,
2798 fl4.flowi4_tos, res.fi, 0);
2799 } else {
2800 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2801 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
2802 }
2803 if (err < 0)
2804 goto errout_free;
2805
2806 rcu_read_unlock();
2807
2808 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2809 errout:
2810 return err;
2811
2812 errout_free:
2813 rcu_read_unlock();
2814 kfree_skb(skb);
2815 goto errout;
2816 }
2817
2818 void ip_rt_multicast_event(struct in_device *in_dev)
2819 {
2820 rt_cache_flush(dev_net(in_dev->dev));
2821 }
2822
2823 #ifdef CONFIG_SYSCTL
2824 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2825 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2826 static int ip_rt_gc_elasticity __read_mostly = 8;
2827 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
2828
2829 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2830 void __user *buffer,
2831 size_t *lenp, loff_t *ppos)
2832 {
2833 struct net *net = (struct net *)__ctl->extra1;
2834
2835 if (write) {
2836 rt_cache_flush(net);
2837 fnhe_genid_bump(net);
2838 return 0;
2839 }
2840
2841 return -EINVAL;
2842 }
2843
2844 static struct ctl_table ipv4_route_table[] = {
2845 {
2846 .procname = "gc_thresh",
2847 .data = &ipv4_dst_ops.gc_thresh,
2848 .maxlen = sizeof(int),
2849 .mode = 0644,
2850 .proc_handler = proc_dointvec,
2851 },
2852 {
2853 .procname = "max_size",
2854 .data = &ip_rt_max_size,
2855 .maxlen = sizeof(int),
2856 .mode = 0644,
2857 .proc_handler = proc_dointvec,
2858 },
2859 {
2860 /* Deprecated. Use gc_min_interval_ms */
2861
2862 .procname = "gc_min_interval",
2863 .data = &ip_rt_gc_min_interval,
2864 .maxlen = sizeof(int),
2865 .mode = 0644,
2866 .proc_handler = proc_dointvec_jiffies,
2867 },
2868 {
2869 .procname = "gc_min_interval_ms",
2870 .data = &ip_rt_gc_min_interval,
2871 .maxlen = sizeof(int),
2872 .mode = 0644,
2873 .proc_handler = proc_dointvec_ms_jiffies,
2874 },
2875 {
2876 .procname = "gc_timeout",
2877 .data = &ip_rt_gc_timeout,
2878 .maxlen = sizeof(int),
2879 .mode = 0644,
2880 .proc_handler = proc_dointvec_jiffies,
2881 },
2882 {
2883 .procname = "gc_interval",
2884 .data = &ip_rt_gc_interval,
2885 .maxlen = sizeof(int),
2886 .mode = 0644,
2887 .proc_handler = proc_dointvec_jiffies,
2888 },
2889 {
2890 .procname = "redirect_load",
2891 .data = &ip_rt_redirect_load,
2892 .maxlen = sizeof(int),
2893 .mode = 0644,
2894 .proc_handler = proc_dointvec,
2895 },
2896 {
2897 .procname = "redirect_number",
2898 .data = &ip_rt_redirect_number,
2899 .maxlen = sizeof(int),
2900 .mode = 0644,
2901 .proc_handler = proc_dointvec,
2902 },
2903 {
2904 .procname = "redirect_silence",
2905 .data = &ip_rt_redirect_silence,
2906 .maxlen = sizeof(int),
2907 .mode = 0644,
2908 .proc_handler = proc_dointvec,
2909 },
2910 {
2911 .procname = "error_cost",
2912 .data = &ip_rt_error_cost,
2913 .maxlen = sizeof(int),
2914 .mode = 0644,
2915 .proc_handler = proc_dointvec,
2916 },
2917 {
2918 .procname = "error_burst",
2919 .data = &ip_rt_error_burst,
2920 .maxlen = sizeof(int),
2921 .mode = 0644,
2922 .proc_handler = proc_dointvec,
2923 },
2924 {
2925 .procname = "gc_elasticity",
2926 .data = &ip_rt_gc_elasticity,
2927 .maxlen = sizeof(int),
2928 .mode = 0644,
2929 .proc_handler = proc_dointvec,
2930 },
2931 {
2932 .procname = "mtu_expires",
2933 .data = &ip_rt_mtu_expires,
2934 .maxlen = sizeof(int),
2935 .mode = 0644,
2936 .proc_handler = proc_dointvec_jiffies,
2937 },
2938 {
2939 .procname = "min_pmtu",
2940 .data = &ip_rt_min_pmtu,
2941 .maxlen = sizeof(int),
2942 .mode = 0644,
2943 .proc_handler = proc_dointvec_minmax,
2944 .extra1 = &ip_min_valid_pmtu,
2945 },
2946 {
2947 .procname = "min_adv_mss",
2948 .data = &ip_rt_min_advmss,
2949 .maxlen = sizeof(int),
2950 .mode = 0644,
2951 .proc_handler = proc_dointvec,
2952 },
2953 { }
2954 };
2955
2956 static struct ctl_table ipv4_route_flush_table[] = {
2957 {
2958 .procname = "flush",
2959 .maxlen = sizeof(int),
2960 .mode = 0200,
2961 .proc_handler = ipv4_sysctl_rtcache_flush,
2962 },
2963 { },
2964 };
2965
2966 static __net_init int sysctl_route_net_init(struct net *net)
2967 {
2968 struct ctl_table *tbl;
2969
2970 tbl = ipv4_route_flush_table;
2971 if (!net_eq(net, &init_net)) {
2972 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2973 if (!tbl)
2974 goto err_dup;
2975
2976 /* Don't export sysctls to unprivileged users */
2977 if (net->user_ns != &init_user_ns)
2978 tbl[0].procname = NULL;
2979 }
2980 tbl[0].extra1 = net;
2981
2982 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2983 if (!net->ipv4.route_hdr)
2984 goto err_reg;
2985 return 0;
2986
2987 err_reg:
2988 if (tbl != ipv4_route_flush_table)
2989 kfree(tbl);
2990 err_dup:
2991 return -ENOMEM;
2992 }
2993
2994 static __net_exit void sysctl_route_net_exit(struct net *net)
2995 {
2996 struct ctl_table *tbl;
2997
2998 tbl = net->ipv4.route_hdr->ctl_table_arg;
2999 unregister_net_sysctl_table(net->ipv4.route_hdr);
3000 BUG_ON(tbl == ipv4_route_flush_table);
3001 kfree(tbl);
3002 }
3003
3004 static __net_initdata struct pernet_operations sysctl_route_ops = {
3005 .init = sysctl_route_net_init,
3006 .exit = sysctl_route_net_exit,
3007 };
3008 #endif
3009
3010 static __net_init int rt_genid_init(struct net *net)
3011 {
3012 atomic_set(&net->ipv4.rt_genid, 0);
3013 atomic_set(&net->fnhe_genid, 0);
3014 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3015 return 0;
3016 }
3017
3018 static __net_initdata struct pernet_operations rt_genid_ops = {
3019 .init = rt_genid_init,
3020 };
3021
3022 static int __net_init ipv4_inetpeer_init(struct net *net)
3023 {
3024 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3025
3026 if (!bp)
3027 return -ENOMEM;
3028 inet_peer_base_init(bp);
3029 net->ipv4.peers = bp;
3030 return 0;
3031 }
3032
3033 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3034 {
3035 struct inet_peer_base *bp = net->ipv4.peers;
3036
3037 net->ipv4.peers = NULL;
3038 inetpeer_invalidate_tree(bp);
3039 kfree(bp);
3040 }
3041
3042 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3043 .init = ipv4_inetpeer_init,
3044 .exit = ipv4_inetpeer_exit,
3045 };
3046
3047 #ifdef CONFIG_IP_ROUTE_CLASSID
3048 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3049 #endif /* CONFIG_IP_ROUTE_CLASSID */
3050
3051 int __init ip_rt_init(void)
3052 {
3053 int cpu;
3054
3055 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
3056 if (!ip_idents)
3057 panic("IP: failed to allocate ip_idents\n");
3058
3059 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3060
3061 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3062 if (!ip_tstamps)
3063 panic("IP: failed to allocate ip_tstamps\n");
3064
3065 for_each_possible_cpu(cpu) {
3066 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3067
3068 INIT_LIST_HEAD(&ul->head);
3069 spin_lock_init(&ul->lock);
3070 }
3071 #ifdef CONFIG_IP_ROUTE_CLASSID
3072 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3073 if (!ip_rt_acct)
3074 panic("IP: failed to allocate ip_rt_acct\n");
3075 #endif
3076
3077 ipv4_dst_ops.kmem_cachep =
3078 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3079 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3080
3081 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3082
3083 if (dst_entries_init(&ipv4_dst_ops) < 0)
3084 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3085
3086 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3087 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3088
3089 ipv4_dst_ops.gc_thresh = ~0;
3090 ip_rt_max_size = INT_MAX;
3091
3092 devinet_init();
3093 ip_fib_init();
3094
3095 if (ip_rt_proc_init())
3096 pr_err("Unable to create route proc files\n");
3097 #ifdef CONFIG_XFRM
3098 xfrm_init();
3099 xfrm4_init();
3100 #endif
3101 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3102 RTNL_FLAG_DOIT_UNLOCKED);
3103
3104 #ifdef CONFIG_SYSCTL
3105 register_pernet_subsys(&sysctl_route_ops);
3106 #endif
3107 register_pernet_subsys(&rt_genid_ops);
3108 register_pernet_subsys(&ipv4_inetpeer_ops);
3109 return 0;
3110 }
3111
3112 #ifdef CONFIG_SYSCTL
3113 /*
3114 * We really need to sanitize the damn ipv4 init order, then all
3115 * this nonsense will go away.
3116 */
3117 void __init ip_static_sysctl_init(void)
3118 {
3119 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3120 }
3121 #endif
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