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Merge tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block
[mirror_ubuntu-hirsute-kernel.git] / net / ipv4 / route.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * ROUTE - implementation of the IP router.
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Alan Cox, <gw4pts@gw4pts.ampr.org>
12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
14 *
15 * Fixes:
16 * Alan Cox : Verify area fixes.
17 * Alan Cox : cli() protects routing changes
18 * Rui Oliveira : ICMP routing table updates
19 * (rco@di.uminho.pt) Routing table insertion and update
20 * Linus Torvalds : Rewrote bits to be sensible
21 * Alan Cox : Added BSD route gw semantics
22 * Alan Cox : Super /proc >4K
23 * Alan Cox : MTU in route table
24 * Alan Cox : MSS actually. Also added the window
25 * clamper.
26 * Sam Lantinga : Fixed route matching in rt_del()
27 * Alan Cox : Routing cache support.
28 * Alan Cox : Removed compatibility cruft.
29 * Alan Cox : RTF_REJECT support.
30 * Alan Cox : TCP irtt support.
31 * Jonathan Naylor : Added Metric support.
32 * Miquel van Smoorenburg : BSD API fixes.
33 * Miquel van Smoorenburg : Metrics.
34 * Alan Cox : Use __u32 properly
35 * Alan Cox : Aligned routing errors more closely with BSD
36 * our system is still very different.
37 * Alan Cox : Faster /proc handling
38 * Alexey Kuznetsov : Massive rework to support tree based routing,
39 * routing caches and better behaviour.
40 *
41 * Olaf Erb : irtt wasn't being copied right.
42 * Bjorn Ekwall : Kerneld route support.
43 * Alan Cox : Multicast fixed (I hope)
44 * Pavel Krauz : Limited broadcast fixed
45 * Mike McLagan : Routing by source
46 * Alexey Kuznetsov : End of old history. Split to fib.c and
47 * route.c and rewritten from scratch.
48 * Andi Kleen : Load-limit warning messages.
49 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
53 * Marc Boucher : routing by fwmark
54 * Robert Olsson : Added rt_cache statistics
55 * Arnaldo C. Melo : Convert proc stuff to seq_file
56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
58 * Ilia Sotnikov : Removed TOS from hash calculations
59 */
60
61 #define pr_fmt(fmt) "IPv4: " fmt
62
63 #include <linux/module.h>
64 #include <linux/uaccess.h>
65 #include <linux/bitops.h>
66 #include <linux/types.h>
67 #include <linux/kernel.h>
68 #include <linux/mm.h>
69 #include <linux/string.h>
70 #include <linux/socket.h>
71 #include <linux/sockios.h>
72 #include <linux/errno.h>
73 #include <linux/in.h>
74 #include <linux/inet.h>
75 #include <linux/netdevice.h>
76 #include <linux/proc_fs.h>
77 #include <linux/init.h>
78 #include <linux/skbuff.h>
79 #include <linux/inetdevice.h>
80 #include <linux/igmp.h>
81 #include <linux/pkt_sched.h>
82 #include <linux/mroute.h>
83 #include <linux/netfilter_ipv4.h>
84 #include <linux/random.h>
85 #include <linux/rcupdate.h>
86 #include <linux/times.h>
87 #include <linux/slab.h>
88 #include <linux/jhash.h>
89 #include <net/dst.h>
90 #include <net/dst_metadata.h>
91 #include <net/net_namespace.h>
92 #include <net/protocol.h>
93 #include <net/ip.h>
94 #include <net/route.h>
95 #include <net/inetpeer.h>
96 #include <net/sock.h>
97 #include <net/ip_fib.h>
98 #include <net/nexthop.h>
99 #include <net/arp.h>
100 #include <net/tcp.h>
101 #include <net/icmp.h>
102 #include <net/xfrm.h>
103 #include <net/lwtunnel.h>
104 #include <net/netevent.h>
105 #include <net/rtnetlink.h>
106 #ifdef CONFIG_SYSCTL
107 #include <linux/sysctl.h>
108 #endif
109 #include <net/secure_seq.h>
110 #include <net/ip_tunnels.h>
111 #include <net/l3mdev.h>
112
113 #include "fib_lookup.h"
114
115 #define RT_FL_TOS(oldflp4) \
116 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
117
118 #define RT_GC_TIMEOUT (300*HZ)
119
120 static int ip_rt_max_size;
121 static int ip_rt_redirect_number __read_mostly = 9;
122 static int ip_rt_redirect_load __read_mostly = HZ / 50;
123 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
124 static int ip_rt_error_cost __read_mostly = HZ;
125 static int ip_rt_error_burst __read_mostly = 5 * HZ;
126 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
127 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
128 static int ip_rt_min_advmss __read_mostly = 256;
129
130 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
131
132 /*
133 * Interface to generic destination cache.
134 */
135
136 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
137 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
138 static unsigned int ipv4_mtu(const struct dst_entry *dst);
139 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
140 static void ipv4_link_failure(struct sk_buff *skb);
141 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
142 struct sk_buff *skb, u32 mtu);
143 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
144 struct sk_buff *skb);
145 static void ipv4_dst_destroy(struct dst_entry *dst);
146
147 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
148 {
149 WARN_ON(1);
150 return NULL;
151 }
152
153 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
154 struct sk_buff *skb,
155 const void *daddr);
156 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
157
158 static struct dst_ops ipv4_dst_ops = {
159 .family = AF_INET,
160 .check = ipv4_dst_check,
161 .default_advmss = ipv4_default_advmss,
162 .mtu = ipv4_mtu,
163 .cow_metrics = ipv4_cow_metrics,
164 .destroy = ipv4_dst_destroy,
165 .negative_advice = ipv4_negative_advice,
166 .link_failure = ipv4_link_failure,
167 .update_pmtu = ip_rt_update_pmtu,
168 .redirect = ip_do_redirect,
169 .local_out = __ip_local_out,
170 .neigh_lookup = ipv4_neigh_lookup,
171 .confirm_neigh = ipv4_confirm_neigh,
172 };
173
174 #define ECN_OR_COST(class) TC_PRIO_##class
175
176 const __u8 ip_tos2prio[16] = {
177 TC_PRIO_BESTEFFORT,
178 ECN_OR_COST(BESTEFFORT),
179 TC_PRIO_BESTEFFORT,
180 ECN_OR_COST(BESTEFFORT),
181 TC_PRIO_BULK,
182 ECN_OR_COST(BULK),
183 TC_PRIO_BULK,
184 ECN_OR_COST(BULK),
185 TC_PRIO_INTERACTIVE,
186 ECN_OR_COST(INTERACTIVE),
187 TC_PRIO_INTERACTIVE,
188 ECN_OR_COST(INTERACTIVE),
189 TC_PRIO_INTERACTIVE_BULK,
190 ECN_OR_COST(INTERACTIVE_BULK),
191 TC_PRIO_INTERACTIVE_BULK,
192 ECN_OR_COST(INTERACTIVE_BULK)
193 };
194 EXPORT_SYMBOL(ip_tos2prio);
195
196 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
197 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
198
199 #ifdef CONFIG_PROC_FS
200 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
201 {
202 if (*pos)
203 return NULL;
204 return SEQ_START_TOKEN;
205 }
206
207 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
208 {
209 ++*pos;
210 return NULL;
211 }
212
213 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
214 {
215 }
216
217 static int rt_cache_seq_show(struct seq_file *seq, void *v)
218 {
219 if (v == SEQ_START_TOKEN)
220 seq_printf(seq, "%-127s\n",
221 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
222 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
223 "HHUptod\tSpecDst");
224 return 0;
225 }
226
227 static const struct seq_operations rt_cache_seq_ops = {
228 .start = rt_cache_seq_start,
229 .next = rt_cache_seq_next,
230 .stop = rt_cache_seq_stop,
231 .show = rt_cache_seq_show,
232 };
233
234 static int rt_cache_seq_open(struct inode *inode, struct file *file)
235 {
236 return seq_open(file, &rt_cache_seq_ops);
237 }
238
239 static const struct file_operations rt_cache_seq_fops = {
240 .open = rt_cache_seq_open,
241 .read = seq_read,
242 .llseek = seq_lseek,
243 .release = seq_release,
244 };
245
246
247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
248 {
249 int cpu;
250
251 if (*pos == 0)
252 return SEQ_START_TOKEN;
253
254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
255 if (!cpu_possible(cpu))
256 continue;
257 *pos = cpu+1;
258 return &per_cpu(rt_cache_stat, cpu);
259 }
260 return NULL;
261 }
262
263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
264 {
265 int cpu;
266
267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
268 if (!cpu_possible(cpu))
269 continue;
270 *pos = cpu+1;
271 return &per_cpu(rt_cache_stat, cpu);
272 }
273 return NULL;
274
275 }
276
277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
278 {
279
280 }
281
282 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
283 {
284 struct rt_cache_stat *st = v;
285
286 if (v == SEQ_START_TOKEN) {
287 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
288 return 0;
289 }
290
291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
293 dst_entries_get_slow(&ipv4_dst_ops),
294 0, /* st->in_hit */
295 st->in_slow_tot,
296 st->in_slow_mc,
297 st->in_no_route,
298 st->in_brd,
299 st->in_martian_dst,
300 st->in_martian_src,
301
302 0, /* st->out_hit */
303 st->out_slow_tot,
304 st->out_slow_mc,
305
306 0, /* st->gc_total */
307 0, /* st->gc_ignored */
308 0, /* st->gc_goal_miss */
309 0, /* st->gc_dst_overflow */
310 0, /* st->in_hlist_search */
311 0 /* st->out_hlist_search */
312 );
313 return 0;
314 }
315
316 static const struct seq_operations rt_cpu_seq_ops = {
317 .start = rt_cpu_seq_start,
318 .next = rt_cpu_seq_next,
319 .stop = rt_cpu_seq_stop,
320 .show = rt_cpu_seq_show,
321 };
322
323
324 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
325 {
326 return seq_open(file, &rt_cpu_seq_ops);
327 }
328
329 static const struct file_operations rt_cpu_seq_fops = {
330 .open = rt_cpu_seq_open,
331 .read = seq_read,
332 .llseek = seq_lseek,
333 .release = seq_release,
334 };
335
336 #ifdef CONFIG_IP_ROUTE_CLASSID
337 static int rt_acct_proc_show(struct seq_file *m, void *v)
338 {
339 struct ip_rt_acct *dst, *src;
340 unsigned int i, j;
341
342 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
343 if (!dst)
344 return -ENOMEM;
345
346 for_each_possible_cpu(i) {
347 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
348 for (j = 0; j < 256; j++) {
349 dst[j].o_bytes += src[j].o_bytes;
350 dst[j].o_packets += src[j].o_packets;
351 dst[j].i_bytes += src[j].i_bytes;
352 dst[j].i_packets += src[j].i_packets;
353 }
354 }
355
356 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
357 kfree(dst);
358 return 0;
359 }
360 #endif
361
362 static int __net_init ip_rt_do_proc_init(struct net *net)
363 {
364 struct proc_dir_entry *pde;
365
366 pde = proc_create("rt_cache", 0444, net->proc_net,
367 &rt_cache_seq_fops);
368 if (!pde)
369 goto err1;
370
371 pde = proc_create("rt_cache", 0444,
372 net->proc_net_stat, &rt_cpu_seq_fops);
373 if (!pde)
374 goto err2;
375
376 #ifdef CONFIG_IP_ROUTE_CLASSID
377 pde = proc_create_single("rt_acct", 0, net->proc_net,
378 rt_acct_proc_show);
379 if (!pde)
380 goto err3;
381 #endif
382 return 0;
383
384 #ifdef CONFIG_IP_ROUTE_CLASSID
385 err3:
386 remove_proc_entry("rt_cache", net->proc_net_stat);
387 #endif
388 err2:
389 remove_proc_entry("rt_cache", net->proc_net);
390 err1:
391 return -ENOMEM;
392 }
393
394 static void __net_exit ip_rt_do_proc_exit(struct net *net)
395 {
396 remove_proc_entry("rt_cache", net->proc_net_stat);
397 remove_proc_entry("rt_cache", net->proc_net);
398 #ifdef CONFIG_IP_ROUTE_CLASSID
399 remove_proc_entry("rt_acct", net->proc_net);
400 #endif
401 }
402
403 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
404 .init = ip_rt_do_proc_init,
405 .exit = ip_rt_do_proc_exit,
406 };
407
408 static int __init ip_rt_proc_init(void)
409 {
410 return register_pernet_subsys(&ip_rt_proc_ops);
411 }
412
413 #else
414 static inline int ip_rt_proc_init(void)
415 {
416 return 0;
417 }
418 #endif /* CONFIG_PROC_FS */
419
420 static inline bool rt_is_expired(const struct rtable *rth)
421 {
422 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
423 }
424
425 void rt_cache_flush(struct net *net)
426 {
427 rt_genid_bump_ipv4(net);
428 }
429
430 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
431 struct sk_buff *skb,
432 const void *daddr)
433 {
434 const struct rtable *rt = container_of(dst, struct rtable, dst);
435 struct net_device *dev = dst->dev;
436 struct neighbour *n;
437
438 rcu_read_lock_bh();
439
440 if (likely(rt->rt_gw_family == AF_INET)) {
441 n = ip_neigh_gw4(dev, rt->rt_gw4);
442 } else if (rt->rt_gw_family == AF_INET6) {
443 n = ip_neigh_gw6(dev, &rt->rt_gw6);
444 } else {
445 __be32 pkey;
446
447 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
448 n = ip_neigh_gw4(dev, pkey);
449 }
450
451 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
452 n = NULL;
453
454 rcu_read_unlock_bh();
455
456 return n;
457 }
458
459 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
460 {
461 const struct rtable *rt = container_of(dst, struct rtable, dst);
462 struct net_device *dev = dst->dev;
463 const __be32 *pkey = daddr;
464
465 if (rt->rt_gw_family == AF_INET) {
466 pkey = (const __be32 *)&rt->rt_gw4;
467 } else if (rt->rt_gw_family == AF_INET6) {
468 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
469 } else if (!daddr ||
470 (rt->rt_flags &
471 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
472 return;
473 }
474 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
475 }
476
477 #define IP_IDENTS_SZ 2048u
478
479 static atomic_t *ip_idents __read_mostly;
480 static u32 *ip_tstamps __read_mostly;
481
482 /* In order to protect privacy, we add a perturbation to identifiers
483 * if one generator is seldom used. This makes hard for an attacker
484 * to infer how many packets were sent between two points in time.
485 */
486 u32 ip_idents_reserve(u32 hash, int segs)
487 {
488 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
489 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
490 u32 old = READ_ONCE(*p_tstamp);
491 u32 now = (u32)jiffies;
492 u32 new, delta = 0;
493
494 if (old != now && cmpxchg(p_tstamp, old, now) == old)
495 delta = prandom_u32_max(now - old);
496
497 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
498 do {
499 old = (u32)atomic_read(p_id);
500 new = old + delta + segs;
501 } while (atomic_cmpxchg(p_id, old, new) != old);
502
503 return new - segs;
504 }
505 EXPORT_SYMBOL(ip_idents_reserve);
506
507 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
508 {
509 u32 hash, id;
510
511 /* Note the following code is not safe, but this is okay. */
512 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
513 get_random_bytes(&net->ipv4.ip_id_key,
514 sizeof(net->ipv4.ip_id_key));
515
516 hash = siphash_3u32((__force u32)iph->daddr,
517 (__force u32)iph->saddr,
518 iph->protocol,
519 &net->ipv4.ip_id_key);
520 id = ip_idents_reserve(hash, segs);
521 iph->id = htons(id);
522 }
523 EXPORT_SYMBOL(__ip_select_ident);
524
525 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
526 const struct sock *sk,
527 const struct iphdr *iph,
528 int oif, u8 tos,
529 u8 prot, u32 mark, int flow_flags)
530 {
531 if (sk) {
532 const struct inet_sock *inet = inet_sk(sk);
533
534 oif = sk->sk_bound_dev_if;
535 mark = sk->sk_mark;
536 tos = RT_CONN_FLAGS(sk);
537 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
538 }
539 flowi4_init_output(fl4, oif, mark, tos,
540 RT_SCOPE_UNIVERSE, prot,
541 flow_flags,
542 iph->daddr, iph->saddr, 0, 0,
543 sock_net_uid(net, sk));
544 }
545
546 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
547 const struct sock *sk)
548 {
549 const struct net *net = dev_net(skb->dev);
550 const struct iphdr *iph = ip_hdr(skb);
551 int oif = skb->dev->ifindex;
552 u8 tos = RT_TOS(iph->tos);
553 u8 prot = iph->protocol;
554 u32 mark = skb->mark;
555
556 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
557 }
558
559 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
560 {
561 const struct inet_sock *inet = inet_sk(sk);
562 const struct ip_options_rcu *inet_opt;
563 __be32 daddr = inet->inet_daddr;
564
565 rcu_read_lock();
566 inet_opt = rcu_dereference(inet->inet_opt);
567 if (inet_opt && inet_opt->opt.srr)
568 daddr = inet_opt->opt.faddr;
569 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
570 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
571 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
572 inet_sk_flowi_flags(sk),
573 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
574 rcu_read_unlock();
575 }
576
577 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
578 const struct sk_buff *skb)
579 {
580 if (skb)
581 build_skb_flow_key(fl4, skb, sk);
582 else
583 build_sk_flow_key(fl4, sk);
584 }
585
586 static DEFINE_SPINLOCK(fnhe_lock);
587
588 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
589 {
590 struct rtable *rt;
591
592 rt = rcu_dereference(fnhe->fnhe_rth_input);
593 if (rt) {
594 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
595 dst_dev_put(&rt->dst);
596 dst_release(&rt->dst);
597 }
598 rt = rcu_dereference(fnhe->fnhe_rth_output);
599 if (rt) {
600 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
601 dst_dev_put(&rt->dst);
602 dst_release(&rt->dst);
603 }
604 }
605
606 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
607 {
608 struct fib_nh_exception *fnhe, *oldest;
609
610 oldest = rcu_dereference(hash->chain);
611 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
612 fnhe = rcu_dereference(fnhe->fnhe_next)) {
613 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
614 oldest = fnhe;
615 }
616 fnhe_flush_routes(oldest);
617 return oldest;
618 }
619
620 static inline u32 fnhe_hashfun(__be32 daddr)
621 {
622 static u32 fnhe_hashrnd __read_mostly;
623 u32 hval;
624
625 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
626 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
627 return hash_32(hval, FNHE_HASH_SHIFT);
628 }
629
630 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
631 {
632 rt->rt_pmtu = fnhe->fnhe_pmtu;
633 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
634 rt->dst.expires = fnhe->fnhe_expires;
635
636 if (fnhe->fnhe_gw) {
637 rt->rt_flags |= RTCF_REDIRECTED;
638 rt->rt_gw_family = AF_INET;
639 rt->rt_gw4 = fnhe->fnhe_gw;
640 }
641 }
642
643 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
644 __be32 gw, u32 pmtu, bool lock,
645 unsigned long expires)
646 {
647 struct fnhe_hash_bucket *hash;
648 struct fib_nh_exception *fnhe;
649 struct rtable *rt;
650 u32 genid, hval;
651 unsigned int i;
652 int depth;
653
654 genid = fnhe_genid(dev_net(nhc->nhc_dev));
655 hval = fnhe_hashfun(daddr);
656
657 spin_lock_bh(&fnhe_lock);
658
659 hash = rcu_dereference(nhc->nhc_exceptions);
660 if (!hash) {
661 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
662 if (!hash)
663 goto out_unlock;
664 rcu_assign_pointer(nhc->nhc_exceptions, hash);
665 }
666
667 hash += hval;
668
669 depth = 0;
670 for (fnhe = rcu_dereference(hash->chain); fnhe;
671 fnhe = rcu_dereference(fnhe->fnhe_next)) {
672 if (fnhe->fnhe_daddr == daddr)
673 break;
674 depth++;
675 }
676
677 if (fnhe) {
678 if (fnhe->fnhe_genid != genid)
679 fnhe->fnhe_genid = genid;
680 if (gw)
681 fnhe->fnhe_gw = gw;
682 if (pmtu) {
683 fnhe->fnhe_pmtu = pmtu;
684 fnhe->fnhe_mtu_locked = lock;
685 }
686 fnhe->fnhe_expires = max(1UL, expires);
687 /* Update all cached dsts too */
688 rt = rcu_dereference(fnhe->fnhe_rth_input);
689 if (rt)
690 fill_route_from_fnhe(rt, fnhe);
691 rt = rcu_dereference(fnhe->fnhe_rth_output);
692 if (rt)
693 fill_route_from_fnhe(rt, fnhe);
694 } else {
695 if (depth > FNHE_RECLAIM_DEPTH)
696 fnhe = fnhe_oldest(hash);
697 else {
698 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
699 if (!fnhe)
700 goto out_unlock;
701
702 fnhe->fnhe_next = hash->chain;
703 rcu_assign_pointer(hash->chain, fnhe);
704 }
705 fnhe->fnhe_genid = genid;
706 fnhe->fnhe_daddr = daddr;
707 fnhe->fnhe_gw = gw;
708 fnhe->fnhe_pmtu = pmtu;
709 fnhe->fnhe_mtu_locked = lock;
710 fnhe->fnhe_expires = max(1UL, expires);
711
712 /* Exception created; mark the cached routes for the nexthop
713 * stale, so anyone caching it rechecks if this exception
714 * applies to them.
715 */
716 rt = rcu_dereference(nhc->nhc_rth_input);
717 if (rt)
718 rt->dst.obsolete = DST_OBSOLETE_KILL;
719
720 for_each_possible_cpu(i) {
721 struct rtable __rcu **prt;
722 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
723 rt = rcu_dereference(*prt);
724 if (rt)
725 rt->dst.obsolete = DST_OBSOLETE_KILL;
726 }
727 }
728
729 fnhe->fnhe_stamp = jiffies;
730
731 out_unlock:
732 spin_unlock_bh(&fnhe_lock);
733 }
734
735 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
736 bool kill_route)
737 {
738 __be32 new_gw = icmp_hdr(skb)->un.gateway;
739 __be32 old_gw = ip_hdr(skb)->saddr;
740 struct net_device *dev = skb->dev;
741 struct in_device *in_dev;
742 struct fib_result res;
743 struct neighbour *n;
744 struct net *net;
745
746 switch (icmp_hdr(skb)->code & 7) {
747 case ICMP_REDIR_NET:
748 case ICMP_REDIR_NETTOS:
749 case ICMP_REDIR_HOST:
750 case ICMP_REDIR_HOSTTOS:
751 break;
752
753 default:
754 return;
755 }
756
757 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
758 return;
759
760 in_dev = __in_dev_get_rcu(dev);
761 if (!in_dev)
762 return;
763
764 net = dev_net(dev);
765 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
766 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
767 ipv4_is_zeronet(new_gw))
768 goto reject_redirect;
769
770 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
771 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
772 goto reject_redirect;
773 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
774 goto reject_redirect;
775 } else {
776 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
777 goto reject_redirect;
778 }
779
780 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
781 if (!n)
782 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
783 if (!IS_ERR(n)) {
784 if (!(n->nud_state & NUD_VALID)) {
785 neigh_event_send(n, NULL);
786 } else {
787 if (fib_lookup(net, fl4, &res, 0) == 0) {
788 struct fib_nh_common *nhc = FIB_RES_NHC(res);
789
790 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
791 0, false,
792 jiffies + ip_rt_gc_timeout);
793 }
794 if (kill_route)
795 rt->dst.obsolete = DST_OBSOLETE_KILL;
796 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
797 }
798 neigh_release(n);
799 }
800 return;
801
802 reject_redirect:
803 #ifdef CONFIG_IP_ROUTE_VERBOSE
804 if (IN_DEV_LOG_MARTIANS(in_dev)) {
805 const struct iphdr *iph = (const struct iphdr *) skb->data;
806 __be32 daddr = iph->daddr;
807 __be32 saddr = iph->saddr;
808
809 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
810 " Advised path = %pI4 -> %pI4\n",
811 &old_gw, dev->name, &new_gw,
812 &saddr, &daddr);
813 }
814 #endif
815 ;
816 }
817
818 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
819 {
820 struct rtable *rt;
821 struct flowi4 fl4;
822 const struct iphdr *iph = (const struct iphdr *) skb->data;
823 struct net *net = dev_net(skb->dev);
824 int oif = skb->dev->ifindex;
825 u8 tos = RT_TOS(iph->tos);
826 u8 prot = iph->protocol;
827 u32 mark = skb->mark;
828
829 rt = (struct rtable *) dst;
830
831 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
832 __ip_do_redirect(rt, skb, &fl4, true);
833 }
834
835 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
836 {
837 struct rtable *rt = (struct rtable *)dst;
838 struct dst_entry *ret = dst;
839
840 if (rt) {
841 if (dst->obsolete > 0) {
842 ip_rt_put(rt);
843 ret = NULL;
844 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
845 rt->dst.expires) {
846 ip_rt_put(rt);
847 ret = NULL;
848 }
849 }
850 return ret;
851 }
852
853 /*
854 * Algorithm:
855 * 1. The first ip_rt_redirect_number redirects are sent
856 * with exponential backoff, then we stop sending them at all,
857 * assuming that the host ignores our redirects.
858 * 2. If we did not see packets requiring redirects
859 * during ip_rt_redirect_silence, we assume that the host
860 * forgot redirected route and start to send redirects again.
861 *
862 * This algorithm is much cheaper and more intelligent than dumb load limiting
863 * in icmp.c.
864 *
865 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
866 * and "frag. need" (breaks PMTU discovery) in icmp.c.
867 */
868
869 void ip_rt_send_redirect(struct sk_buff *skb)
870 {
871 struct rtable *rt = skb_rtable(skb);
872 struct in_device *in_dev;
873 struct inet_peer *peer;
874 struct net *net;
875 int log_martians;
876 int vif;
877
878 rcu_read_lock();
879 in_dev = __in_dev_get_rcu(rt->dst.dev);
880 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
881 rcu_read_unlock();
882 return;
883 }
884 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
885 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
886 rcu_read_unlock();
887
888 net = dev_net(rt->dst.dev);
889 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
890 if (!peer) {
891 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
892 rt_nexthop(rt, ip_hdr(skb)->daddr));
893 return;
894 }
895
896 /* No redirected packets during ip_rt_redirect_silence;
897 * reset the algorithm.
898 */
899 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
900 peer->rate_tokens = 0;
901 peer->n_redirects = 0;
902 }
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->n_redirects >= 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 ++peer->n_redirects;
925 #ifdef CONFIG_IP_ROUTE_VERBOSE
926 if (log_martians &&
927 peer->rate_tokens == ip_rt_redirect_number)
928 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
929 &ip_hdr(skb)->saddr, inet_iif(skb),
930 &ip_hdr(skb)->daddr, &gw);
931 #endif
932 }
933 out_put_peer:
934 inet_putpeer(peer);
935 }
936
937 static int ip_error(struct sk_buff *skb)
938 {
939 struct rtable *rt = skb_rtable(skb);
940 struct net_device *dev = skb->dev;
941 struct in_device *in_dev;
942 struct inet_peer *peer;
943 unsigned long now;
944 struct net *net;
945 bool send;
946 int code;
947
948 if (netif_is_l3_master(skb->dev)) {
949 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
950 if (!dev)
951 goto out;
952 }
953
954 in_dev = __in_dev_get_rcu(dev);
955
956 /* IP on this device is disabled. */
957 if (!in_dev)
958 goto out;
959
960 net = dev_net(rt->dst.dev);
961 if (!IN_DEV_FORWARD(in_dev)) {
962 switch (rt->dst.error) {
963 case EHOSTUNREACH:
964 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
965 break;
966
967 case ENETUNREACH:
968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
969 break;
970 }
971 goto out;
972 }
973
974 switch (rt->dst.error) {
975 case EINVAL:
976 default:
977 goto out;
978 case EHOSTUNREACH:
979 code = ICMP_HOST_UNREACH;
980 break;
981 case ENETUNREACH:
982 code = ICMP_NET_UNREACH;
983 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
984 break;
985 case EACCES:
986 code = ICMP_PKT_FILTERED;
987 break;
988 }
989
990 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
991 l3mdev_master_ifindex(skb->dev), 1);
992
993 send = true;
994 if (peer) {
995 now = jiffies;
996 peer->rate_tokens += now - peer->rate_last;
997 if (peer->rate_tokens > ip_rt_error_burst)
998 peer->rate_tokens = ip_rt_error_burst;
999 peer->rate_last = now;
1000 if (peer->rate_tokens >= ip_rt_error_cost)
1001 peer->rate_tokens -= ip_rt_error_cost;
1002 else
1003 send = false;
1004 inet_putpeer(peer);
1005 }
1006 if (send)
1007 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1008
1009 out: kfree_skb(skb);
1010 return 0;
1011 }
1012
1013 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1014 {
1015 struct dst_entry *dst = &rt->dst;
1016 u32 old_mtu = ipv4_mtu(dst);
1017 struct fib_result res;
1018 bool lock = false;
1019
1020 if (ip_mtu_locked(dst))
1021 return;
1022
1023 if (old_mtu < mtu)
1024 return;
1025
1026 if (mtu < ip_rt_min_pmtu) {
1027 lock = true;
1028 mtu = min(old_mtu, ip_rt_min_pmtu);
1029 }
1030
1031 if (rt->rt_pmtu == mtu && !lock &&
1032 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1033 return;
1034
1035 rcu_read_lock();
1036 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1037 struct fib_nh_common *nhc = FIB_RES_NHC(res);
1038
1039 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1040 jiffies + ip_rt_mtu_expires);
1041 }
1042 rcu_read_unlock();
1043 }
1044
1045 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1046 struct sk_buff *skb, u32 mtu)
1047 {
1048 struct rtable *rt = (struct rtable *) dst;
1049 struct flowi4 fl4;
1050
1051 ip_rt_build_flow_key(&fl4, sk, skb);
1052 __ip_rt_update_pmtu(rt, &fl4, mtu);
1053 }
1054
1055 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1056 int oif, u8 protocol)
1057 {
1058 const struct iphdr *iph = (const struct iphdr *) skb->data;
1059 struct flowi4 fl4;
1060 struct rtable *rt;
1061 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1062
1063 __build_flow_key(net, &fl4, NULL, iph, oif,
1064 RT_TOS(iph->tos), protocol, mark, 0);
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, u8 protocol)
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, 0, 0);
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.
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_send_dest_unreach(struct sk_buff *skb)
1196 {
1197 struct ip_options opt;
1198 int res;
1199
1200 /* Recompile ip options since IPCB may not be valid anymore.
1201 * Also check we have a reasonable ipv4 header.
1202 */
1203 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1204 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1205 return;
1206
1207 memset(&opt, 0, sizeof(opt));
1208 if (ip_hdr(skb)->ihl > 5) {
1209 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1210 return;
1211 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1212
1213 rcu_read_lock();
1214 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL);
1215 rcu_read_unlock();
1216
1217 if (res)
1218 return;
1219 }
1220 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1221 }
1222
1223 static void ipv4_link_failure(struct sk_buff *skb)
1224 {
1225 struct rtable *rt;
1226
1227 ipv4_send_dest_unreach(skb);
1228
1229 rt = skb_rtable(skb);
1230 if (rt)
1231 dst_set_expires(&rt->dst, 0);
1232 }
1233
1234 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1235 {
1236 pr_debug("%s: %pI4 -> %pI4, %s\n",
1237 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1238 skb->dev ? skb->dev->name : "?");
1239 kfree_skb(skb);
1240 WARN_ON(1);
1241 return 0;
1242 }
1243
1244 /*
1245 We do not cache source address of outgoing interface,
1246 because it is used only by IP RR, TS and SRR options,
1247 so that it out of fast path.
1248
1249 BTW remember: "addr" is allowed to be not aligned
1250 in IP options!
1251 */
1252
1253 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1254 {
1255 __be32 src;
1256
1257 if (rt_is_output_route(rt))
1258 src = ip_hdr(skb)->saddr;
1259 else {
1260 struct fib_result res;
1261 struct iphdr *iph = ip_hdr(skb);
1262 struct flowi4 fl4 = {
1263 .daddr = iph->daddr,
1264 .saddr = iph->saddr,
1265 .flowi4_tos = RT_TOS(iph->tos),
1266 .flowi4_oif = rt->dst.dev->ifindex,
1267 .flowi4_iif = skb->dev->ifindex,
1268 .flowi4_mark = skb->mark,
1269 };
1270
1271 rcu_read_lock();
1272 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1273 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1274 else
1275 src = inet_select_addr(rt->dst.dev,
1276 rt_nexthop(rt, iph->daddr),
1277 RT_SCOPE_UNIVERSE);
1278 rcu_read_unlock();
1279 }
1280 memcpy(addr, &src, 4);
1281 }
1282
1283 #ifdef CONFIG_IP_ROUTE_CLASSID
1284 static void set_class_tag(struct rtable *rt, u32 tag)
1285 {
1286 if (!(rt->dst.tclassid & 0xFFFF))
1287 rt->dst.tclassid |= tag & 0xFFFF;
1288 if (!(rt->dst.tclassid & 0xFFFF0000))
1289 rt->dst.tclassid |= tag & 0xFFFF0000;
1290 }
1291 #endif
1292
1293 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1294 {
1295 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1296 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1297 ip_rt_min_advmss);
1298
1299 return min(advmss, IPV4_MAX_PMTU - header_size);
1300 }
1301
1302 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1303 {
1304 const struct rtable *rt = (const struct rtable *) dst;
1305 unsigned int mtu = rt->rt_pmtu;
1306
1307 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1308 mtu = dst_metric_raw(dst, RTAX_MTU);
1309
1310 if (mtu)
1311 return mtu;
1312
1313 mtu = READ_ONCE(dst->dev->mtu);
1314
1315 if (unlikely(ip_mtu_locked(dst))) {
1316 if (rt->rt_gw_family && mtu > 576)
1317 mtu = 576;
1318 }
1319
1320 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1321
1322 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1323 }
1324
1325 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1326 {
1327 struct fnhe_hash_bucket *hash;
1328 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1329 u32 hval = fnhe_hashfun(daddr);
1330
1331 spin_lock_bh(&fnhe_lock);
1332
1333 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1334 lockdep_is_held(&fnhe_lock));
1335 hash += hval;
1336
1337 fnhe_p = &hash->chain;
1338 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1339 while (fnhe) {
1340 if (fnhe->fnhe_daddr == daddr) {
1341 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1342 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1343 /* set fnhe_daddr to 0 to ensure it won't bind with
1344 * new dsts in rt_bind_exception().
1345 */
1346 fnhe->fnhe_daddr = 0;
1347 fnhe_flush_routes(fnhe);
1348 kfree_rcu(fnhe, rcu);
1349 break;
1350 }
1351 fnhe_p = &fnhe->fnhe_next;
1352 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1353 lockdep_is_held(&fnhe_lock));
1354 }
1355
1356 spin_unlock_bh(&fnhe_lock);
1357 }
1358
1359 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1360 __be32 daddr)
1361 {
1362 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1363 struct fib_nh_exception *fnhe;
1364 u32 hval;
1365
1366 if (!hash)
1367 return NULL;
1368
1369 hval = fnhe_hashfun(daddr);
1370
1371 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1372 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1373 if (fnhe->fnhe_daddr == daddr) {
1374 if (fnhe->fnhe_expires &&
1375 time_after(jiffies, fnhe->fnhe_expires)) {
1376 ip_del_fnhe(nhc, daddr);
1377 break;
1378 }
1379 return fnhe;
1380 }
1381 }
1382 return NULL;
1383 }
1384
1385 /* MTU selection:
1386 * 1. mtu on route is locked - use it
1387 * 2. mtu from nexthop exception
1388 * 3. mtu from egress device
1389 */
1390
1391 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1392 {
1393 struct fib_nh_common *nhc = res->nhc;
1394 struct net_device *dev = nhc->nhc_dev;
1395 struct fib_info *fi = res->fi;
1396 u32 mtu = 0;
1397
1398 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1399 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1400 mtu = fi->fib_mtu;
1401
1402 if (likely(!mtu)) {
1403 struct fib_nh_exception *fnhe;
1404
1405 fnhe = find_exception(nhc, daddr);
1406 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1407 mtu = fnhe->fnhe_pmtu;
1408 }
1409
1410 if (likely(!mtu))
1411 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1412
1413 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1414 }
1415
1416 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1417 __be32 daddr, const bool do_cache)
1418 {
1419 bool ret = false;
1420
1421 spin_lock_bh(&fnhe_lock);
1422
1423 if (daddr == fnhe->fnhe_daddr) {
1424 struct rtable __rcu **porig;
1425 struct rtable *orig;
1426 int genid = fnhe_genid(dev_net(rt->dst.dev));
1427
1428 if (rt_is_input_route(rt))
1429 porig = &fnhe->fnhe_rth_input;
1430 else
1431 porig = &fnhe->fnhe_rth_output;
1432 orig = rcu_dereference(*porig);
1433
1434 if (fnhe->fnhe_genid != genid) {
1435 fnhe->fnhe_genid = genid;
1436 fnhe->fnhe_gw = 0;
1437 fnhe->fnhe_pmtu = 0;
1438 fnhe->fnhe_expires = 0;
1439 fnhe->fnhe_mtu_locked = false;
1440 fnhe_flush_routes(fnhe);
1441 orig = NULL;
1442 }
1443 fill_route_from_fnhe(rt, fnhe);
1444 if (!rt->rt_gw4) {
1445 rt->rt_gw4 = daddr;
1446 rt->rt_gw_family = AF_INET;
1447 }
1448
1449 if (do_cache) {
1450 dst_hold(&rt->dst);
1451 rcu_assign_pointer(*porig, rt);
1452 if (orig) {
1453 dst_dev_put(&orig->dst);
1454 dst_release(&orig->dst);
1455 }
1456 ret = true;
1457 }
1458
1459 fnhe->fnhe_stamp = jiffies;
1460 }
1461 spin_unlock_bh(&fnhe_lock);
1462
1463 return ret;
1464 }
1465
1466 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1467 {
1468 struct rtable *orig, *prev, **p;
1469 bool ret = true;
1470
1471 if (rt_is_input_route(rt)) {
1472 p = (struct rtable **)&nhc->nhc_rth_input;
1473 } else {
1474 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1475 }
1476 orig = *p;
1477
1478 /* hold dst before doing cmpxchg() to avoid race condition
1479 * on this dst
1480 */
1481 dst_hold(&rt->dst);
1482 prev = cmpxchg(p, orig, rt);
1483 if (prev == orig) {
1484 if (orig) {
1485 dst_dev_put(&orig->dst);
1486 dst_release(&orig->dst);
1487 }
1488 } else {
1489 dst_release(&rt->dst);
1490 ret = false;
1491 }
1492
1493 return ret;
1494 }
1495
1496 struct uncached_list {
1497 spinlock_t lock;
1498 struct list_head head;
1499 };
1500
1501 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1502
1503 void rt_add_uncached_list(struct rtable *rt)
1504 {
1505 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1506
1507 rt->rt_uncached_list = ul;
1508
1509 spin_lock_bh(&ul->lock);
1510 list_add_tail(&rt->rt_uncached, &ul->head);
1511 spin_unlock_bh(&ul->lock);
1512 }
1513
1514 void rt_del_uncached_list(struct rtable *rt)
1515 {
1516 if (!list_empty(&rt->rt_uncached)) {
1517 struct uncached_list *ul = rt->rt_uncached_list;
1518
1519 spin_lock_bh(&ul->lock);
1520 list_del(&rt->rt_uncached);
1521 spin_unlock_bh(&ul->lock);
1522 }
1523 }
1524
1525 static void ipv4_dst_destroy(struct dst_entry *dst)
1526 {
1527 struct rtable *rt = (struct rtable *)dst;
1528
1529 ip_dst_metrics_put(dst);
1530 rt_del_uncached_list(rt);
1531 }
1532
1533 void rt_flush_dev(struct net_device *dev)
1534 {
1535 struct rtable *rt;
1536 int cpu;
1537
1538 for_each_possible_cpu(cpu) {
1539 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1540
1541 spin_lock_bh(&ul->lock);
1542 list_for_each_entry(rt, &ul->head, rt_uncached) {
1543 if (rt->dst.dev != dev)
1544 continue;
1545 rt->dst.dev = blackhole_netdev;
1546 dev_hold(rt->dst.dev);
1547 dev_put(dev);
1548 }
1549 spin_unlock_bh(&ul->lock);
1550 }
1551 }
1552
1553 static bool rt_cache_valid(const struct rtable *rt)
1554 {
1555 return rt &&
1556 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1557 !rt_is_expired(rt);
1558 }
1559
1560 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1561 const struct fib_result *res,
1562 struct fib_nh_exception *fnhe,
1563 struct fib_info *fi, u16 type, u32 itag,
1564 const bool do_cache)
1565 {
1566 bool cached = false;
1567
1568 if (fi) {
1569 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1570
1571 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1572 rt->rt_gw_family = nhc->nhc_gw_family;
1573 /* only INET and INET6 are supported */
1574 if (likely(nhc->nhc_gw_family == AF_INET))
1575 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1576 else
1577 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1578 }
1579
1580 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1581
1582 #ifdef CONFIG_IP_ROUTE_CLASSID
1583 if (nhc->nhc_family == AF_INET) {
1584 struct fib_nh *nh;
1585
1586 nh = container_of(nhc, struct fib_nh, nh_common);
1587 rt->dst.tclassid = nh->nh_tclassid;
1588 }
1589 #endif
1590 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1591 if (unlikely(fnhe))
1592 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1593 else if (do_cache)
1594 cached = rt_cache_route(nhc, rt);
1595 if (unlikely(!cached)) {
1596 /* Routes we intend to cache in nexthop exception or
1597 * FIB nexthop have the DST_NOCACHE bit clear.
1598 * However, if we are unsuccessful at storing this
1599 * route into the cache we really need to set it.
1600 */
1601 if (!rt->rt_gw4) {
1602 rt->rt_gw_family = AF_INET;
1603 rt->rt_gw4 = daddr;
1604 }
1605 rt_add_uncached_list(rt);
1606 }
1607 } else
1608 rt_add_uncached_list(rt);
1609
1610 #ifdef CONFIG_IP_ROUTE_CLASSID
1611 #ifdef CONFIG_IP_MULTIPLE_TABLES
1612 set_class_tag(rt, res->tclassid);
1613 #endif
1614 set_class_tag(rt, itag);
1615 #endif
1616 }
1617
1618 struct rtable *rt_dst_alloc(struct net_device *dev,
1619 unsigned int flags, u16 type,
1620 bool nopolicy, bool noxfrm, bool will_cache)
1621 {
1622 struct rtable *rt;
1623
1624 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1625 (will_cache ? 0 : DST_HOST) |
1626 (nopolicy ? DST_NOPOLICY : 0) |
1627 (noxfrm ? DST_NOXFRM : 0));
1628
1629 if (rt) {
1630 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1631 rt->rt_flags = flags;
1632 rt->rt_type = type;
1633 rt->rt_is_input = 0;
1634 rt->rt_iif = 0;
1635 rt->rt_pmtu = 0;
1636 rt->rt_mtu_locked = 0;
1637 rt->rt_gw_family = 0;
1638 rt->rt_gw4 = 0;
1639 INIT_LIST_HEAD(&rt->rt_uncached);
1640
1641 rt->dst.output = ip_output;
1642 if (flags & RTCF_LOCAL)
1643 rt->dst.input = ip_local_deliver;
1644 }
1645
1646 return rt;
1647 }
1648 EXPORT_SYMBOL(rt_dst_alloc);
1649
1650 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1651 {
1652 struct rtable *new_rt;
1653
1654 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1655 rt->dst.flags);
1656
1657 if (new_rt) {
1658 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1659 new_rt->rt_flags = rt->rt_flags;
1660 new_rt->rt_type = rt->rt_type;
1661 new_rt->rt_is_input = rt->rt_is_input;
1662 new_rt->rt_iif = rt->rt_iif;
1663 new_rt->rt_pmtu = rt->rt_pmtu;
1664 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1665 new_rt->rt_gw_family = rt->rt_gw_family;
1666 if (rt->rt_gw_family == AF_INET)
1667 new_rt->rt_gw4 = rt->rt_gw4;
1668 else if (rt->rt_gw_family == AF_INET6)
1669 new_rt->rt_gw6 = rt->rt_gw6;
1670 INIT_LIST_HEAD(&new_rt->rt_uncached);
1671
1672 new_rt->dst.flags |= DST_HOST;
1673 new_rt->dst.input = rt->dst.input;
1674 new_rt->dst.output = rt->dst.output;
1675 new_rt->dst.error = rt->dst.error;
1676 new_rt->dst.lastuse = jiffies;
1677 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1678 }
1679 return new_rt;
1680 }
1681 EXPORT_SYMBOL(rt_dst_clone);
1682
1683 /* called in rcu_read_lock() section */
1684 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1685 u8 tos, struct net_device *dev,
1686 struct in_device *in_dev, u32 *itag)
1687 {
1688 int err;
1689
1690 /* Primary sanity checks. */
1691 if (!in_dev)
1692 return -EINVAL;
1693
1694 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1695 skb->protocol != htons(ETH_P_IP))
1696 return -EINVAL;
1697
1698 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1699 return -EINVAL;
1700
1701 if (ipv4_is_zeronet(saddr)) {
1702 if (!ipv4_is_local_multicast(daddr) &&
1703 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1704 return -EINVAL;
1705 } else {
1706 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1707 in_dev, itag);
1708 if (err < 0)
1709 return err;
1710 }
1711 return 0;
1712 }
1713
1714 /* called in rcu_read_lock() section */
1715 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1716 u8 tos, struct net_device *dev, int our)
1717 {
1718 struct in_device *in_dev = __in_dev_get_rcu(dev);
1719 unsigned int flags = RTCF_MULTICAST;
1720 struct rtable *rth;
1721 u32 itag = 0;
1722 int err;
1723
1724 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1725 if (err)
1726 return err;
1727
1728 if (our)
1729 flags |= RTCF_LOCAL;
1730
1731 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1732 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1733 if (!rth)
1734 return -ENOBUFS;
1735
1736 #ifdef CONFIG_IP_ROUTE_CLASSID
1737 rth->dst.tclassid = itag;
1738 #endif
1739 rth->dst.output = ip_rt_bug;
1740 rth->rt_is_input= 1;
1741
1742 #ifdef CONFIG_IP_MROUTE
1743 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1744 rth->dst.input = ip_mr_input;
1745 #endif
1746 RT_CACHE_STAT_INC(in_slow_mc);
1747
1748 skb_dst_set(skb, &rth->dst);
1749 return 0;
1750 }
1751
1752
1753 static void ip_handle_martian_source(struct net_device *dev,
1754 struct in_device *in_dev,
1755 struct sk_buff *skb,
1756 __be32 daddr,
1757 __be32 saddr)
1758 {
1759 RT_CACHE_STAT_INC(in_martian_src);
1760 #ifdef CONFIG_IP_ROUTE_VERBOSE
1761 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1762 /*
1763 * RFC1812 recommendation, if source is martian,
1764 * the only hint is MAC header.
1765 */
1766 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1767 &daddr, &saddr, dev->name);
1768 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1769 print_hex_dump(KERN_WARNING, "ll header: ",
1770 DUMP_PREFIX_OFFSET, 16, 1,
1771 skb_mac_header(skb),
1772 dev->hard_header_len, false);
1773 }
1774 }
1775 #endif
1776 }
1777
1778 /* called in rcu_read_lock() section */
1779 static int __mkroute_input(struct sk_buff *skb,
1780 const struct fib_result *res,
1781 struct in_device *in_dev,
1782 __be32 daddr, __be32 saddr, u32 tos)
1783 {
1784 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1785 struct net_device *dev = nhc->nhc_dev;
1786 struct fib_nh_exception *fnhe;
1787 struct rtable *rth;
1788 int err;
1789 struct in_device *out_dev;
1790 bool do_cache;
1791 u32 itag = 0;
1792
1793 /* get a working reference to the output device */
1794 out_dev = __in_dev_get_rcu(dev);
1795 if (!out_dev) {
1796 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1797 return -EINVAL;
1798 }
1799
1800 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1801 in_dev->dev, in_dev, &itag);
1802 if (err < 0) {
1803 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1804 saddr);
1805
1806 goto cleanup;
1807 }
1808
1809 do_cache = res->fi && !itag;
1810 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1811 skb->protocol == htons(ETH_P_IP)) {
1812 __be32 gw;
1813
1814 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1815 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1816 inet_addr_onlink(out_dev, saddr, gw))
1817 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1818 }
1819
1820 if (skb->protocol != htons(ETH_P_IP)) {
1821 /* Not IP (i.e. ARP). Do not create route, if it is
1822 * invalid for proxy arp. DNAT routes are always valid.
1823 *
1824 * Proxy arp feature have been extended to allow, ARP
1825 * replies back to the same interface, to support
1826 * Private VLAN switch technologies. See arp.c.
1827 */
1828 if (out_dev == in_dev &&
1829 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1830 err = -EINVAL;
1831 goto cleanup;
1832 }
1833 }
1834
1835 fnhe = find_exception(nhc, daddr);
1836 if (do_cache) {
1837 if (fnhe)
1838 rth = rcu_dereference(fnhe->fnhe_rth_input);
1839 else
1840 rth = rcu_dereference(nhc->nhc_rth_input);
1841 if (rt_cache_valid(rth)) {
1842 skb_dst_set_noref(skb, &rth->dst);
1843 goto out;
1844 }
1845 }
1846
1847 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1848 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1849 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1850 if (!rth) {
1851 err = -ENOBUFS;
1852 goto cleanup;
1853 }
1854
1855 rth->rt_is_input = 1;
1856 RT_CACHE_STAT_INC(in_slow_tot);
1857
1858 rth->dst.input = ip_forward;
1859
1860 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1861 do_cache);
1862 lwtunnel_set_redirect(&rth->dst);
1863 skb_dst_set(skb, &rth->dst);
1864 out:
1865 err = 0;
1866 cleanup:
1867 return err;
1868 }
1869
1870 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1871 /* To make ICMP packets follow the right flow, the multipath hash is
1872 * calculated from the inner IP addresses.
1873 */
1874 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1875 struct flow_keys *hash_keys)
1876 {
1877 const struct iphdr *outer_iph = ip_hdr(skb);
1878 const struct iphdr *key_iph = outer_iph;
1879 const struct iphdr *inner_iph;
1880 const struct icmphdr *icmph;
1881 struct iphdr _inner_iph;
1882 struct icmphdr _icmph;
1883
1884 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1885 goto out;
1886
1887 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1888 goto out;
1889
1890 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1891 &_icmph);
1892 if (!icmph)
1893 goto out;
1894
1895 if (icmph->type != ICMP_DEST_UNREACH &&
1896 icmph->type != ICMP_REDIRECT &&
1897 icmph->type != ICMP_TIME_EXCEEDED &&
1898 icmph->type != ICMP_PARAMETERPROB)
1899 goto out;
1900
1901 inner_iph = skb_header_pointer(skb,
1902 outer_iph->ihl * 4 + sizeof(_icmph),
1903 sizeof(_inner_iph), &_inner_iph);
1904 if (!inner_iph)
1905 goto out;
1906
1907 key_iph = inner_iph;
1908 out:
1909 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1910 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1911 }
1912
1913 /* if skb is set it will be used and fl4 can be NULL */
1914 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1915 const struct sk_buff *skb, struct flow_keys *flkeys)
1916 {
1917 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
1918 struct flow_keys hash_keys;
1919 u32 mhash;
1920
1921 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1922 case 0:
1923 memset(&hash_keys, 0, sizeof(hash_keys));
1924 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1925 if (skb) {
1926 ip_multipath_l3_keys(skb, &hash_keys);
1927 } else {
1928 hash_keys.addrs.v4addrs.src = fl4->saddr;
1929 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1930 }
1931 break;
1932 case 1:
1933 /* skb is currently provided only when forwarding */
1934 if (skb) {
1935 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1936 struct flow_keys keys;
1937
1938 /* short-circuit if we already have L4 hash present */
1939 if (skb->l4_hash)
1940 return skb_get_hash_raw(skb) >> 1;
1941
1942 memset(&hash_keys, 0, sizeof(hash_keys));
1943
1944 if (!flkeys) {
1945 skb_flow_dissect_flow_keys(skb, &keys, flag);
1946 flkeys = &keys;
1947 }
1948
1949 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1950 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1951 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1952 hash_keys.ports.src = flkeys->ports.src;
1953 hash_keys.ports.dst = flkeys->ports.dst;
1954 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1955 } else {
1956 memset(&hash_keys, 0, sizeof(hash_keys));
1957 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1958 hash_keys.addrs.v4addrs.src = fl4->saddr;
1959 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1960 hash_keys.ports.src = fl4->fl4_sport;
1961 hash_keys.ports.dst = fl4->fl4_dport;
1962 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1963 }
1964 break;
1965 case 2:
1966 memset(&hash_keys, 0, sizeof(hash_keys));
1967 /* skb is currently provided only when forwarding */
1968 if (skb) {
1969 struct flow_keys keys;
1970
1971 skb_flow_dissect_flow_keys(skb, &keys, 0);
1972 /* Inner can be v4 or v6 */
1973 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1974 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1975 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1976 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1977 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1978 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1979 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1980 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1981 hash_keys.tags.flow_label = keys.tags.flow_label;
1982 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1983 } else {
1984 /* Same as case 0 */
1985 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1986 ip_multipath_l3_keys(skb, &hash_keys);
1987 }
1988 } else {
1989 /* Same as case 0 */
1990 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1991 hash_keys.addrs.v4addrs.src = fl4->saddr;
1992 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1993 }
1994 break;
1995 }
1996 mhash = flow_hash_from_keys(&hash_keys);
1997
1998 if (multipath_hash)
1999 mhash = jhash_2words(mhash, multipath_hash, 0);
2000
2001 return mhash >> 1;
2002 }
2003 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
2004
2005 static int ip_mkroute_input(struct sk_buff *skb,
2006 struct fib_result *res,
2007 struct in_device *in_dev,
2008 __be32 daddr, __be32 saddr, u32 tos,
2009 struct flow_keys *hkeys)
2010 {
2011 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2012 if (res->fi && fib_info_num_path(res->fi) > 1) {
2013 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2014
2015 fib_select_multipath(res, h);
2016 }
2017 #endif
2018
2019 /* create a routing cache entry */
2020 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2021 }
2022
2023 /*
2024 * NOTE. We drop all the packets that has local source
2025 * addresses, because every properly looped back packet
2026 * must have correct destination already attached by output routine.
2027 *
2028 * Such approach solves two big problems:
2029 * 1. Not simplex devices are handled properly.
2030 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2031 * called with rcu_read_lock()
2032 */
2033
2034 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2035 u8 tos, struct net_device *dev,
2036 struct fib_result *res)
2037 {
2038 struct in_device *in_dev = __in_dev_get_rcu(dev);
2039 struct flow_keys *flkeys = NULL, _flkeys;
2040 struct net *net = dev_net(dev);
2041 struct ip_tunnel_info *tun_info;
2042 int err = -EINVAL;
2043 unsigned int flags = 0;
2044 u32 itag = 0;
2045 struct rtable *rth;
2046 struct flowi4 fl4;
2047 bool do_cache = true;
2048
2049 /* IP on this device is disabled. */
2050
2051 if (!in_dev)
2052 goto out;
2053
2054 /* Check for the most weird martians, which can be not detected
2055 by fib_lookup.
2056 */
2057
2058 tun_info = skb_tunnel_info(skb);
2059 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2060 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2061 else
2062 fl4.flowi4_tun_key.tun_id = 0;
2063 skb_dst_drop(skb);
2064
2065 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2066 goto martian_source;
2067
2068 res->fi = NULL;
2069 res->table = NULL;
2070 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2071 goto brd_input;
2072
2073 /* Accept zero addresses only to limited broadcast;
2074 * I even do not know to fix it or not. Waiting for complains :-)
2075 */
2076 if (ipv4_is_zeronet(saddr))
2077 goto martian_source;
2078
2079 if (ipv4_is_zeronet(daddr))
2080 goto martian_destination;
2081
2082 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2083 * and call it once if daddr or/and saddr are loopback addresses
2084 */
2085 if (ipv4_is_loopback(daddr)) {
2086 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2087 goto martian_destination;
2088 } else if (ipv4_is_loopback(saddr)) {
2089 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2090 goto martian_source;
2091 }
2092
2093 /*
2094 * Now we are ready to route packet.
2095 */
2096 fl4.flowi4_oif = 0;
2097 fl4.flowi4_iif = dev->ifindex;
2098 fl4.flowi4_mark = skb->mark;
2099 fl4.flowi4_tos = tos;
2100 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2101 fl4.flowi4_flags = 0;
2102 fl4.daddr = daddr;
2103 fl4.saddr = saddr;
2104 fl4.flowi4_uid = sock_net_uid(net, NULL);
2105
2106 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2107 flkeys = &_flkeys;
2108 } else {
2109 fl4.flowi4_proto = 0;
2110 fl4.fl4_sport = 0;
2111 fl4.fl4_dport = 0;
2112 }
2113
2114 err = fib_lookup(net, &fl4, res, 0);
2115 if (err != 0) {
2116 if (!IN_DEV_FORWARD(in_dev))
2117 err = -EHOSTUNREACH;
2118 goto no_route;
2119 }
2120
2121 if (res->type == RTN_BROADCAST) {
2122 if (IN_DEV_BFORWARD(in_dev))
2123 goto make_route;
2124 /* not do cache if bc_forwarding is enabled */
2125 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))
2126 do_cache = false;
2127 goto brd_input;
2128 }
2129
2130 if (res->type == RTN_LOCAL) {
2131 err = fib_validate_source(skb, saddr, daddr, tos,
2132 0, dev, in_dev, &itag);
2133 if (err < 0)
2134 goto martian_source;
2135 goto local_input;
2136 }
2137
2138 if (!IN_DEV_FORWARD(in_dev)) {
2139 err = -EHOSTUNREACH;
2140 goto no_route;
2141 }
2142 if (res->type != RTN_UNICAST)
2143 goto martian_destination;
2144
2145 make_route:
2146 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2147 out: return err;
2148
2149 brd_input:
2150 if (skb->protocol != htons(ETH_P_IP))
2151 goto e_inval;
2152
2153 if (!ipv4_is_zeronet(saddr)) {
2154 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2155 in_dev, &itag);
2156 if (err < 0)
2157 goto martian_source;
2158 }
2159 flags |= RTCF_BROADCAST;
2160 res->type = RTN_BROADCAST;
2161 RT_CACHE_STAT_INC(in_brd);
2162
2163 local_input:
2164 do_cache &= res->fi && !itag;
2165 if (do_cache) {
2166 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2167
2168 rth = rcu_dereference(nhc->nhc_rth_input);
2169 if (rt_cache_valid(rth)) {
2170 skb_dst_set_noref(skb, &rth->dst);
2171 err = 0;
2172 goto out;
2173 }
2174 }
2175
2176 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2177 flags | RTCF_LOCAL, res->type,
2178 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2179 if (!rth)
2180 goto e_nobufs;
2181
2182 rth->dst.output= ip_rt_bug;
2183 #ifdef CONFIG_IP_ROUTE_CLASSID
2184 rth->dst.tclassid = itag;
2185 #endif
2186 rth->rt_is_input = 1;
2187
2188 RT_CACHE_STAT_INC(in_slow_tot);
2189 if (res->type == RTN_UNREACHABLE) {
2190 rth->dst.input= ip_error;
2191 rth->dst.error= -err;
2192 rth->rt_flags &= ~RTCF_LOCAL;
2193 }
2194
2195 if (do_cache) {
2196 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2197
2198 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2199 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2200 WARN_ON(rth->dst.input == lwtunnel_input);
2201 rth->dst.lwtstate->orig_input = rth->dst.input;
2202 rth->dst.input = lwtunnel_input;
2203 }
2204
2205 if (unlikely(!rt_cache_route(nhc, rth)))
2206 rt_add_uncached_list(rth);
2207 }
2208 skb_dst_set(skb, &rth->dst);
2209 err = 0;
2210 goto out;
2211
2212 no_route:
2213 RT_CACHE_STAT_INC(in_no_route);
2214 res->type = RTN_UNREACHABLE;
2215 res->fi = NULL;
2216 res->table = NULL;
2217 goto local_input;
2218
2219 /*
2220 * Do not cache martian addresses: they should be logged (RFC1812)
2221 */
2222 martian_destination:
2223 RT_CACHE_STAT_INC(in_martian_dst);
2224 #ifdef CONFIG_IP_ROUTE_VERBOSE
2225 if (IN_DEV_LOG_MARTIANS(in_dev))
2226 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2227 &daddr, &saddr, dev->name);
2228 #endif
2229
2230 e_inval:
2231 err = -EINVAL;
2232 goto out;
2233
2234 e_nobufs:
2235 err = -ENOBUFS;
2236 goto out;
2237
2238 martian_source:
2239 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2240 goto out;
2241 }
2242
2243 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2244 u8 tos, struct net_device *dev)
2245 {
2246 struct fib_result res;
2247 int err;
2248
2249 tos &= IPTOS_RT_MASK;
2250 rcu_read_lock();
2251 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2252 rcu_read_unlock();
2253
2254 return err;
2255 }
2256 EXPORT_SYMBOL(ip_route_input_noref);
2257
2258 /* called with rcu_read_lock held */
2259 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2260 u8 tos, struct net_device *dev, struct fib_result *res)
2261 {
2262 /* Multicast recognition logic is moved from route cache to here.
2263 The problem was that too many Ethernet cards have broken/missing
2264 hardware multicast filters :-( As result the host on multicasting
2265 network acquires a lot of useless route cache entries, sort of
2266 SDR messages from all the world. Now we try to get rid of them.
2267 Really, provided software IP multicast filter is organized
2268 reasonably (at least, hashed), it does not result in a slowdown
2269 comparing with route cache reject entries.
2270 Note, that multicast routers are not affected, because
2271 route cache entry is created eventually.
2272 */
2273 if (ipv4_is_multicast(daddr)) {
2274 struct in_device *in_dev = __in_dev_get_rcu(dev);
2275 int our = 0;
2276 int err = -EINVAL;
2277
2278 if (!in_dev)
2279 return err;
2280 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2281 ip_hdr(skb)->protocol);
2282
2283 /* check l3 master if no match yet */
2284 if (!our && netif_is_l3_slave(dev)) {
2285 struct in_device *l3_in_dev;
2286
2287 l3_in_dev = __in_dev_get_rcu(skb->dev);
2288 if (l3_in_dev)
2289 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2290 ip_hdr(skb)->protocol);
2291 }
2292
2293 if (our
2294 #ifdef CONFIG_IP_MROUTE
2295 ||
2296 (!ipv4_is_local_multicast(daddr) &&
2297 IN_DEV_MFORWARD(in_dev))
2298 #endif
2299 ) {
2300 err = ip_route_input_mc(skb, daddr, saddr,
2301 tos, dev, our);
2302 }
2303 return err;
2304 }
2305
2306 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2307 }
2308
2309 /* called with rcu_read_lock() */
2310 static struct rtable *__mkroute_output(const struct fib_result *res,
2311 const struct flowi4 *fl4, int orig_oif,
2312 struct net_device *dev_out,
2313 unsigned int flags)
2314 {
2315 struct fib_info *fi = res->fi;
2316 struct fib_nh_exception *fnhe;
2317 struct in_device *in_dev;
2318 u16 type = res->type;
2319 struct rtable *rth;
2320 bool do_cache;
2321
2322 in_dev = __in_dev_get_rcu(dev_out);
2323 if (!in_dev)
2324 return ERR_PTR(-EINVAL);
2325
2326 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2327 if (ipv4_is_loopback(fl4->saddr) &&
2328 !(dev_out->flags & IFF_LOOPBACK) &&
2329 !netif_is_l3_master(dev_out))
2330 return ERR_PTR(-EINVAL);
2331
2332 if (ipv4_is_lbcast(fl4->daddr))
2333 type = RTN_BROADCAST;
2334 else if (ipv4_is_multicast(fl4->daddr))
2335 type = RTN_MULTICAST;
2336 else if (ipv4_is_zeronet(fl4->daddr))
2337 return ERR_PTR(-EINVAL);
2338
2339 if (dev_out->flags & IFF_LOOPBACK)
2340 flags |= RTCF_LOCAL;
2341
2342 do_cache = true;
2343 if (type == RTN_BROADCAST) {
2344 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2345 fi = NULL;
2346 } else if (type == RTN_MULTICAST) {
2347 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2348 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2349 fl4->flowi4_proto))
2350 flags &= ~RTCF_LOCAL;
2351 else
2352 do_cache = false;
2353 /* If multicast route do not exist use
2354 * default one, but do not gateway in this case.
2355 * Yes, it is hack.
2356 */
2357 if (fi && res->prefixlen < 4)
2358 fi = NULL;
2359 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2360 (orig_oif != dev_out->ifindex)) {
2361 /* For local routes that require a particular output interface
2362 * we do not want to cache the result. Caching the result
2363 * causes incorrect behaviour when there are multiple source
2364 * addresses on the interface, the end result being that if the
2365 * intended recipient is waiting on that interface for the
2366 * packet he won't receive it because it will be delivered on
2367 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2368 * be set to the loopback interface as well.
2369 */
2370 do_cache = false;
2371 }
2372
2373 fnhe = NULL;
2374 do_cache &= fi != NULL;
2375 if (fi) {
2376 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2377 struct rtable __rcu **prth;
2378
2379 fnhe = find_exception(nhc, fl4->daddr);
2380 if (!do_cache)
2381 goto add;
2382 if (fnhe) {
2383 prth = &fnhe->fnhe_rth_output;
2384 } else {
2385 if (unlikely(fl4->flowi4_flags &
2386 FLOWI_FLAG_KNOWN_NH &&
2387 !(nhc->nhc_gw_family &&
2388 nhc->nhc_scope == RT_SCOPE_LINK))) {
2389 do_cache = false;
2390 goto add;
2391 }
2392 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2393 }
2394 rth = rcu_dereference(*prth);
2395 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2396 return rth;
2397 }
2398
2399 add:
2400 rth = rt_dst_alloc(dev_out, flags, type,
2401 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2402 IN_DEV_CONF_GET(in_dev, NOXFRM),
2403 do_cache);
2404 if (!rth)
2405 return ERR_PTR(-ENOBUFS);
2406
2407 rth->rt_iif = orig_oif;
2408
2409 RT_CACHE_STAT_INC(out_slow_tot);
2410
2411 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2412 if (flags & RTCF_LOCAL &&
2413 !(dev_out->flags & IFF_LOOPBACK)) {
2414 rth->dst.output = ip_mc_output;
2415 RT_CACHE_STAT_INC(out_slow_mc);
2416 }
2417 #ifdef CONFIG_IP_MROUTE
2418 if (type == RTN_MULTICAST) {
2419 if (IN_DEV_MFORWARD(in_dev) &&
2420 !ipv4_is_local_multicast(fl4->daddr)) {
2421 rth->dst.input = ip_mr_input;
2422 rth->dst.output = ip_mc_output;
2423 }
2424 }
2425 #endif
2426 }
2427
2428 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2429 lwtunnel_set_redirect(&rth->dst);
2430
2431 return rth;
2432 }
2433
2434 /*
2435 * Major route resolver routine.
2436 */
2437
2438 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2439 const struct sk_buff *skb)
2440 {
2441 __u8 tos = RT_FL_TOS(fl4);
2442 struct fib_result res = {
2443 .type = RTN_UNSPEC,
2444 .fi = NULL,
2445 .table = NULL,
2446 .tclassid = 0,
2447 };
2448 struct rtable *rth;
2449
2450 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2451 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2452 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2453 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2454
2455 rcu_read_lock();
2456 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2457 rcu_read_unlock();
2458
2459 return rth;
2460 }
2461 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2462
2463 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2464 struct fib_result *res,
2465 const struct sk_buff *skb)
2466 {
2467 struct net_device *dev_out = NULL;
2468 int orig_oif = fl4->flowi4_oif;
2469 unsigned int flags = 0;
2470 struct rtable *rth;
2471 int err = -ENETUNREACH;
2472
2473 if (fl4->saddr) {
2474 rth = ERR_PTR(-EINVAL);
2475 if (ipv4_is_multicast(fl4->saddr) ||
2476 ipv4_is_lbcast(fl4->saddr) ||
2477 ipv4_is_zeronet(fl4->saddr))
2478 goto out;
2479
2480 /* I removed check for oif == dev_out->oif here.
2481 It was wrong for two reasons:
2482 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2483 is assigned to multiple interfaces.
2484 2. Moreover, we are allowed to send packets with saddr
2485 of another iface. --ANK
2486 */
2487
2488 if (fl4->flowi4_oif == 0 &&
2489 (ipv4_is_multicast(fl4->daddr) ||
2490 ipv4_is_lbcast(fl4->daddr))) {
2491 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2492 dev_out = __ip_dev_find(net, fl4->saddr, false);
2493 if (!dev_out)
2494 goto out;
2495
2496 /* Special hack: user can direct multicasts
2497 and limited broadcast via necessary interface
2498 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2499 This hack is not just for fun, it allows
2500 vic,vat and friends to work.
2501 They bind socket to loopback, set ttl to zero
2502 and expect that it will work.
2503 From the viewpoint of routing cache they are broken,
2504 because we are not allowed to build multicast path
2505 with loopback source addr (look, routing cache
2506 cannot know, that ttl is zero, so that packet
2507 will not leave this host and route is valid).
2508 Luckily, this hack is good workaround.
2509 */
2510
2511 fl4->flowi4_oif = dev_out->ifindex;
2512 goto make_route;
2513 }
2514
2515 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2516 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2517 if (!__ip_dev_find(net, fl4->saddr, false))
2518 goto out;
2519 }
2520 }
2521
2522
2523 if (fl4->flowi4_oif) {
2524 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2525 rth = ERR_PTR(-ENODEV);
2526 if (!dev_out)
2527 goto out;
2528
2529 /* RACE: Check return value of inet_select_addr instead. */
2530 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2531 rth = ERR_PTR(-ENETUNREACH);
2532 goto out;
2533 }
2534 if (ipv4_is_local_multicast(fl4->daddr) ||
2535 ipv4_is_lbcast(fl4->daddr) ||
2536 fl4->flowi4_proto == IPPROTO_IGMP) {
2537 if (!fl4->saddr)
2538 fl4->saddr = inet_select_addr(dev_out, 0,
2539 RT_SCOPE_LINK);
2540 goto make_route;
2541 }
2542 if (!fl4->saddr) {
2543 if (ipv4_is_multicast(fl4->daddr))
2544 fl4->saddr = inet_select_addr(dev_out, 0,
2545 fl4->flowi4_scope);
2546 else if (!fl4->daddr)
2547 fl4->saddr = inet_select_addr(dev_out, 0,
2548 RT_SCOPE_HOST);
2549 }
2550 }
2551
2552 if (!fl4->daddr) {
2553 fl4->daddr = fl4->saddr;
2554 if (!fl4->daddr)
2555 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2556 dev_out = net->loopback_dev;
2557 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2558 res->type = RTN_LOCAL;
2559 flags |= RTCF_LOCAL;
2560 goto make_route;
2561 }
2562
2563 err = fib_lookup(net, fl4, res, 0);
2564 if (err) {
2565 res->fi = NULL;
2566 res->table = NULL;
2567 if (fl4->flowi4_oif &&
2568 (ipv4_is_multicast(fl4->daddr) ||
2569 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2570 /* Apparently, routing tables are wrong. Assume,
2571 that the destination is on link.
2572
2573 WHY? DW.
2574 Because we are allowed to send to iface
2575 even if it has NO routes and NO assigned
2576 addresses. When oif is specified, routing
2577 tables are looked up with only one purpose:
2578 to catch if destination is gatewayed, rather than
2579 direct. Moreover, if MSG_DONTROUTE is set,
2580 we send packet, ignoring both routing tables
2581 and ifaddr state. --ANK
2582
2583
2584 We could make it even if oif is unknown,
2585 likely IPv6, but we do not.
2586 */
2587
2588 if (fl4->saddr == 0)
2589 fl4->saddr = inet_select_addr(dev_out, 0,
2590 RT_SCOPE_LINK);
2591 res->type = RTN_UNICAST;
2592 goto make_route;
2593 }
2594 rth = ERR_PTR(err);
2595 goto out;
2596 }
2597
2598 if (res->type == RTN_LOCAL) {
2599 if (!fl4->saddr) {
2600 if (res->fi->fib_prefsrc)
2601 fl4->saddr = res->fi->fib_prefsrc;
2602 else
2603 fl4->saddr = fl4->daddr;
2604 }
2605
2606 /* L3 master device is the loopback for that domain */
2607 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2608 net->loopback_dev;
2609
2610 /* make sure orig_oif points to fib result device even
2611 * though packet rx/tx happens over loopback or l3mdev
2612 */
2613 orig_oif = FIB_RES_OIF(*res);
2614
2615 fl4->flowi4_oif = dev_out->ifindex;
2616 flags |= RTCF_LOCAL;
2617 goto make_route;
2618 }
2619
2620 fib_select_path(net, res, fl4, skb);
2621
2622 dev_out = FIB_RES_DEV(*res);
2623 fl4->flowi4_oif = dev_out->ifindex;
2624
2625
2626 make_route:
2627 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2628
2629 out:
2630 return rth;
2631 }
2632
2633 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2634 {
2635 return NULL;
2636 }
2637
2638 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2639 {
2640 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2641
2642 return mtu ? : dst->dev->mtu;
2643 }
2644
2645 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2646 struct sk_buff *skb, u32 mtu)
2647 {
2648 }
2649
2650 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2651 struct sk_buff *skb)
2652 {
2653 }
2654
2655 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2656 unsigned long old)
2657 {
2658 return NULL;
2659 }
2660
2661 static struct dst_ops ipv4_dst_blackhole_ops = {
2662 .family = AF_INET,
2663 .check = ipv4_blackhole_dst_check,
2664 .mtu = ipv4_blackhole_mtu,
2665 .default_advmss = ipv4_default_advmss,
2666 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2667 .redirect = ipv4_rt_blackhole_redirect,
2668 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2669 .neigh_lookup = ipv4_neigh_lookup,
2670 };
2671
2672 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2673 {
2674 struct rtable *ort = (struct rtable *) dst_orig;
2675 struct rtable *rt;
2676
2677 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2678 if (rt) {
2679 struct dst_entry *new = &rt->dst;
2680
2681 new->__use = 1;
2682 new->input = dst_discard;
2683 new->output = dst_discard_out;
2684
2685 new->dev = net->loopback_dev;
2686 if (new->dev)
2687 dev_hold(new->dev);
2688
2689 rt->rt_is_input = ort->rt_is_input;
2690 rt->rt_iif = ort->rt_iif;
2691 rt->rt_pmtu = ort->rt_pmtu;
2692 rt->rt_mtu_locked = ort->rt_mtu_locked;
2693
2694 rt->rt_genid = rt_genid_ipv4(net);
2695 rt->rt_flags = ort->rt_flags;
2696 rt->rt_type = ort->rt_type;
2697 rt->rt_gw_family = ort->rt_gw_family;
2698 if (rt->rt_gw_family == AF_INET)
2699 rt->rt_gw4 = ort->rt_gw4;
2700 else if (rt->rt_gw_family == AF_INET6)
2701 rt->rt_gw6 = ort->rt_gw6;
2702
2703 INIT_LIST_HEAD(&rt->rt_uncached);
2704 }
2705
2706 dst_release(dst_orig);
2707
2708 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2709 }
2710
2711 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2712 const struct sock *sk)
2713 {
2714 struct rtable *rt = __ip_route_output_key(net, flp4);
2715
2716 if (IS_ERR(rt))
2717 return rt;
2718
2719 if (flp4->flowi4_proto)
2720 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2721 flowi4_to_flowi(flp4),
2722 sk, 0);
2723
2724 return rt;
2725 }
2726 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2727
2728 /* called with rcu_read_lock held */
2729 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2730 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2731 struct sk_buff *skb, u32 portid, u32 seq,
2732 unsigned int flags)
2733 {
2734 struct rtmsg *r;
2735 struct nlmsghdr *nlh;
2736 unsigned long expires = 0;
2737 u32 error;
2738 u32 metrics[RTAX_MAX];
2739
2740 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2741 if (!nlh)
2742 return -EMSGSIZE;
2743
2744 r = nlmsg_data(nlh);
2745 r->rtm_family = AF_INET;
2746 r->rtm_dst_len = 32;
2747 r->rtm_src_len = 0;
2748 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2749 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2750 if (nla_put_u32(skb, RTA_TABLE, table_id))
2751 goto nla_put_failure;
2752 r->rtm_type = rt->rt_type;
2753 r->rtm_scope = RT_SCOPE_UNIVERSE;
2754 r->rtm_protocol = RTPROT_UNSPEC;
2755 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2756 if (rt->rt_flags & RTCF_NOTIFY)
2757 r->rtm_flags |= RTM_F_NOTIFY;
2758 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2759 r->rtm_flags |= RTCF_DOREDIRECT;
2760
2761 if (nla_put_in_addr(skb, RTA_DST, dst))
2762 goto nla_put_failure;
2763 if (src) {
2764 r->rtm_src_len = 32;
2765 if (nla_put_in_addr(skb, RTA_SRC, src))
2766 goto nla_put_failure;
2767 }
2768 if (rt->dst.dev &&
2769 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2770 goto nla_put_failure;
2771 #ifdef CONFIG_IP_ROUTE_CLASSID
2772 if (rt->dst.tclassid &&
2773 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2774 goto nla_put_failure;
2775 #endif
2776 if (fl4 && !rt_is_input_route(rt) &&
2777 fl4->saddr != src) {
2778 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2779 goto nla_put_failure;
2780 }
2781 if (rt->rt_gw_family == AF_INET &&
2782 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2783 goto nla_put_failure;
2784 } else if (rt->rt_gw_family == AF_INET6) {
2785 int alen = sizeof(struct in6_addr);
2786 struct nlattr *nla;
2787 struct rtvia *via;
2788
2789 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2790 if (!nla)
2791 goto nla_put_failure;
2792
2793 via = nla_data(nla);
2794 via->rtvia_family = AF_INET6;
2795 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2796 }
2797
2798 expires = rt->dst.expires;
2799 if (expires) {
2800 unsigned long now = jiffies;
2801
2802 if (time_before(now, expires))
2803 expires -= now;
2804 else
2805 expires = 0;
2806 }
2807
2808 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2809 if (rt->rt_pmtu && expires)
2810 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2811 if (rt->rt_mtu_locked && expires)
2812 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2813 if (rtnetlink_put_metrics(skb, metrics) < 0)
2814 goto nla_put_failure;
2815
2816 if (fl4) {
2817 if (fl4->flowi4_mark &&
2818 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2819 goto nla_put_failure;
2820
2821 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2822 nla_put_u32(skb, RTA_UID,
2823 from_kuid_munged(current_user_ns(),
2824 fl4->flowi4_uid)))
2825 goto nla_put_failure;
2826
2827 if (rt_is_input_route(rt)) {
2828 #ifdef CONFIG_IP_MROUTE
2829 if (ipv4_is_multicast(dst) &&
2830 !ipv4_is_local_multicast(dst) &&
2831 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2832 int err = ipmr_get_route(net, skb,
2833 fl4->saddr, fl4->daddr,
2834 r, portid);
2835
2836 if (err <= 0) {
2837 if (err == 0)
2838 return 0;
2839 goto nla_put_failure;
2840 }
2841 } else
2842 #endif
2843 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
2844 goto nla_put_failure;
2845 }
2846 }
2847
2848 error = rt->dst.error;
2849
2850 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2851 goto nla_put_failure;
2852
2853 nlmsg_end(skb, nlh);
2854 return 0;
2855
2856 nla_put_failure:
2857 nlmsg_cancel(skb, nlh);
2858 return -EMSGSIZE;
2859 }
2860
2861 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
2862 struct netlink_callback *cb, u32 table_id,
2863 struct fnhe_hash_bucket *bucket, int genid,
2864 int *fa_index, int fa_start, unsigned int flags)
2865 {
2866 int i;
2867
2868 for (i = 0; i < FNHE_HASH_SIZE; i++) {
2869 struct fib_nh_exception *fnhe;
2870
2871 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
2872 fnhe = rcu_dereference(fnhe->fnhe_next)) {
2873 struct rtable *rt;
2874 int err;
2875
2876 if (*fa_index < fa_start)
2877 goto next;
2878
2879 if (fnhe->fnhe_genid != genid)
2880 goto next;
2881
2882 if (fnhe->fnhe_expires &&
2883 time_after(jiffies, fnhe->fnhe_expires))
2884 goto next;
2885
2886 rt = rcu_dereference(fnhe->fnhe_rth_input);
2887 if (!rt)
2888 rt = rcu_dereference(fnhe->fnhe_rth_output);
2889 if (!rt)
2890 goto next;
2891
2892 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
2893 table_id, NULL, skb,
2894 NETLINK_CB(cb->skb).portid,
2895 cb->nlh->nlmsg_seq, flags);
2896 if (err)
2897 return err;
2898 next:
2899 (*fa_index)++;
2900 }
2901 }
2902
2903 return 0;
2904 }
2905
2906 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
2907 u32 table_id, struct fib_info *fi,
2908 int *fa_index, int fa_start, unsigned int flags)
2909 {
2910 struct net *net = sock_net(cb->skb->sk);
2911 int nhsel, genid = fnhe_genid(net);
2912
2913 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
2914 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
2915 struct fnhe_hash_bucket *bucket;
2916 int err;
2917
2918 if (nhc->nhc_flags & RTNH_F_DEAD)
2919 continue;
2920
2921 rcu_read_lock();
2922 bucket = rcu_dereference(nhc->nhc_exceptions);
2923 err = 0;
2924 if (bucket)
2925 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
2926 genid, fa_index, fa_start,
2927 flags);
2928 rcu_read_unlock();
2929 if (err)
2930 return err;
2931 }
2932
2933 return 0;
2934 }
2935
2936 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
2937 u8 ip_proto, __be16 sport,
2938 __be16 dport)
2939 {
2940 struct sk_buff *skb;
2941 struct iphdr *iph;
2942
2943 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2944 if (!skb)
2945 return NULL;
2946
2947 /* Reserve room for dummy headers, this skb can pass
2948 * through good chunk of routing engine.
2949 */
2950 skb_reset_mac_header(skb);
2951 skb_reset_network_header(skb);
2952 skb->protocol = htons(ETH_P_IP);
2953 iph = skb_put(skb, sizeof(struct iphdr));
2954 iph->protocol = ip_proto;
2955 iph->saddr = src;
2956 iph->daddr = dst;
2957 iph->version = 0x4;
2958 iph->frag_off = 0;
2959 iph->ihl = 0x5;
2960 skb_set_transport_header(skb, skb->len);
2961
2962 switch (iph->protocol) {
2963 case IPPROTO_UDP: {
2964 struct udphdr *udph;
2965
2966 udph = skb_put_zero(skb, sizeof(struct udphdr));
2967 udph->source = sport;
2968 udph->dest = dport;
2969 udph->len = sizeof(struct udphdr);
2970 udph->check = 0;
2971 break;
2972 }
2973 case IPPROTO_TCP: {
2974 struct tcphdr *tcph;
2975
2976 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
2977 tcph->source = sport;
2978 tcph->dest = dport;
2979 tcph->doff = sizeof(struct tcphdr) / 4;
2980 tcph->rst = 1;
2981 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
2982 src, dst, 0);
2983 break;
2984 }
2985 case IPPROTO_ICMP: {
2986 struct icmphdr *icmph;
2987
2988 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
2989 icmph->type = ICMP_ECHO;
2990 icmph->code = 0;
2991 }
2992 }
2993
2994 return skb;
2995 }
2996
2997 static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
2998 const struct nlmsghdr *nlh,
2999 struct nlattr **tb,
3000 struct netlink_ext_ack *extack)
3001 {
3002 struct rtmsg *rtm;
3003 int i, err;
3004
3005 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3006 NL_SET_ERR_MSG(extack,
3007 "ipv4: Invalid header for route get request");
3008 return -EINVAL;
3009 }
3010
3011 if (!netlink_strict_get_check(skb))
3012 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3013 rtm_ipv4_policy, extack);
3014
3015 rtm = nlmsg_data(nlh);
3016 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3017 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3018 rtm->rtm_table || rtm->rtm_protocol ||
3019 rtm->rtm_scope || rtm->rtm_type) {
3020 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3021 return -EINVAL;
3022 }
3023
3024 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3025 RTM_F_LOOKUP_TABLE |
3026 RTM_F_FIB_MATCH)) {
3027 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3028 return -EINVAL;
3029 }
3030
3031 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3032 rtm_ipv4_policy, extack);
3033 if (err)
3034 return err;
3035
3036 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3037 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3038 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3039 return -EINVAL;
3040 }
3041
3042 for (i = 0; i <= RTA_MAX; i++) {
3043 if (!tb[i])
3044 continue;
3045
3046 switch (i) {
3047 case RTA_IIF:
3048 case RTA_OIF:
3049 case RTA_SRC:
3050 case RTA_DST:
3051 case RTA_IP_PROTO:
3052 case RTA_SPORT:
3053 case RTA_DPORT:
3054 case RTA_MARK:
3055 case RTA_UID:
3056 break;
3057 default:
3058 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3059 return -EINVAL;
3060 }
3061 }
3062
3063 return 0;
3064 }
3065
3066 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3067 struct netlink_ext_ack *extack)
3068 {
3069 struct net *net = sock_net(in_skb->sk);
3070 struct nlattr *tb[RTA_MAX+1];
3071 u32 table_id = RT_TABLE_MAIN;
3072 __be16 sport = 0, dport = 0;
3073 struct fib_result res = {};
3074 u8 ip_proto = IPPROTO_UDP;
3075 struct rtable *rt = NULL;
3076 struct sk_buff *skb;
3077 struct rtmsg *rtm;
3078 struct flowi4 fl4 = {};
3079 __be32 dst = 0;
3080 __be32 src = 0;
3081 kuid_t uid;
3082 u32 iif;
3083 int err;
3084 int mark;
3085
3086 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3087 if (err < 0)
3088 return err;
3089
3090 rtm = nlmsg_data(nlh);
3091 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3092 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3093 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3094 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3095 if (tb[RTA_UID])
3096 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3097 else
3098 uid = (iif ? INVALID_UID : current_uid());
3099
3100 if (tb[RTA_IP_PROTO]) {
3101 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3102 &ip_proto, AF_INET, extack);
3103 if (err)
3104 return err;
3105 }
3106
3107 if (tb[RTA_SPORT])
3108 sport = nla_get_be16(tb[RTA_SPORT]);
3109
3110 if (tb[RTA_DPORT])
3111 dport = nla_get_be16(tb[RTA_DPORT]);
3112
3113 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3114 if (!skb)
3115 return -ENOBUFS;
3116
3117 fl4.daddr = dst;
3118 fl4.saddr = src;
3119 fl4.flowi4_tos = rtm->rtm_tos;
3120 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3121 fl4.flowi4_mark = mark;
3122 fl4.flowi4_uid = uid;
3123 if (sport)
3124 fl4.fl4_sport = sport;
3125 if (dport)
3126 fl4.fl4_dport = dport;
3127 fl4.flowi4_proto = ip_proto;
3128
3129 rcu_read_lock();
3130
3131 if (iif) {
3132 struct net_device *dev;
3133
3134 dev = dev_get_by_index_rcu(net, iif);
3135 if (!dev) {
3136 err = -ENODEV;
3137 goto errout_rcu;
3138 }
3139
3140 fl4.flowi4_iif = iif; /* for rt_fill_info */
3141 skb->dev = dev;
3142 skb->mark = mark;
3143 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
3144 dev, &res);
3145
3146 rt = skb_rtable(skb);
3147 if (err == 0 && rt->dst.error)
3148 err = -rt->dst.error;
3149 } else {
3150 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3151 skb->dev = net->loopback_dev;
3152 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3153 err = 0;
3154 if (IS_ERR(rt))
3155 err = PTR_ERR(rt);
3156 else
3157 skb_dst_set(skb, &rt->dst);
3158 }
3159
3160 if (err)
3161 goto errout_rcu;
3162
3163 if (rtm->rtm_flags & RTM_F_NOTIFY)
3164 rt->rt_flags |= RTCF_NOTIFY;
3165
3166 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3167 table_id = res.table ? res.table->tb_id : 0;
3168
3169 /* reset skb for netlink reply msg */
3170 skb_trim(skb, 0);
3171 skb_reset_network_header(skb);
3172 skb_reset_transport_header(skb);
3173 skb_reset_mac_header(skb);
3174
3175 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3176 if (!res.fi) {
3177 err = fib_props[res.type].error;
3178 if (!err)
3179 err = -EHOSTUNREACH;
3180 goto errout_rcu;
3181 }
3182 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3183 nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
3184 rt->rt_type, res.prefix, res.prefixlen,
3185 fl4.flowi4_tos, res.fi, 0);
3186 } else {
3187 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3188 NETLINK_CB(in_skb).portid,
3189 nlh->nlmsg_seq, 0);
3190 }
3191 if (err < 0)
3192 goto errout_rcu;
3193
3194 rcu_read_unlock();
3195
3196 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3197
3198 errout_free:
3199 return err;
3200 errout_rcu:
3201 rcu_read_unlock();
3202 kfree_skb(skb);
3203 goto errout_free;
3204 }
3205
3206 void ip_rt_multicast_event(struct in_device *in_dev)
3207 {
3208 rt_cache_flush(dev_net(in_dev->dev));
3209 }
3210
3211 #ifdef CONFIG_SYSCTL
3212 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3213 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3214 static int ip_rt_gc_elasticity __read_mostly = 8;
3215 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3216
3217 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3218 void __user *buffer,
3219 size_t *lenp, loff_t *ppos)
3220 {
3221 struct net *net = (struct net *)__ctl->extra1;
3222
3223 if (write) {
3224 rt_cache_flush(net);
3225 fnhe_genid_bump(net);
3226 return 0;
3227 }
3228
3229 return -EINVAL;
3230 }
3231
3232 static struct ctl_table ipv4_route_table[] = {
3233 {
3234 .procname = "gc_thresh",
3235 .data = &ipv4_dst_ops.gc_thresh,
3236 .maxlen = sizeof(int),
3237 .mode = 0644,
3238 .proc_handler = proc_dointvec,
3239 },
3240 {
3241 .procname = "max_size",
3242 .data = &ip_rt_max_size,
3243 .maxlen = sizeof(int),
3244 .mode = 0644,
3245 .proc_handler = proc_dointvec,
3246 },
3247 {
3248 /* Deprecated. Use gc_min_interval_ms */
3249
3250 .procname = "gc_min_interval",
3251 .data = &ip_rt_gc_min_interval,
3252 .maxlen = sizeof(int),
3253 .mode = 0644,
3254 .proc_handler = proc_dointvec_jiffies,
3255 },
3256 {
3257 .procname = "gc_min_interval_ms",
3258 .data = &ip_rt_gc_min_interval,
3259 .maxlen = sizeof(int),
3260 .mode = 0644,
3261 .proc_handler = proc_dointvec_ms_jiffies,
3262 },
3263 {
3264 .procname = "gc_timeout",
3265 .data = &ip_rt_gc_timeout,
3266 .maxlen = sizeof(int),
3267 .mode = 0644,
3268 .proc_handler = proc_dointvec_jiffies,
3269 },
3270 {
3271 .procname = "gc_interval",
3272 .data = &ip_rt_gc_interval,
3273 .maxlen = sizeof(int),
3274 .mode = 0644,
3275 .proc_handler = proc_dointvec_jiffies,
3276 },
3277 {
3278 .procname = "redirect_load",
3279 .data = &ip_rt_redirect_load,
3280 .maxlen = sizeof(int),
3281 .mode = 0644,
3282 .proc_handler = proc_dointvec,
3283 },
3284 {
3285 .procname = "redirect_number",
3286 .data = &ip_rt_redirect_number,
3287 .maxlen = sizeof(int),
3288 .mode = 0644,
3289 .proc_handler = proc_dointvec,
3290 },
3291 {
3292 .procname = "redirect_silence",
3293 .data = &ip_rt_redirect_silence,
3294 .maxlen = sizeof(int),
3295 .mode = 0644,
3296 .proc_handler = proc_dointvec,
3297 },
3298 {
3299 .procname = "error_cost",
3300 .data = &ip_rt_error_cost,
3301 .maxlen = sizeof(int),
3302 .mode = 0644,
3303 .proc_handler = proc_dointvec,
3304 },
3305 {
3306 .procname = "error_burst",
3307 .data = &ip_rt_error_burst,
3308 .maxlen = sizeof(int),
3309 .mode = 0644,
3310 .proc_handler = proc_dointvec,
3311 },
3312 {
3313 .procname = "gc_elasticity",
3314 .data = &ip_rt_gc_elasticity,
3315 .maxlen = sizeof(int),
3316 .mode = 0644,
3317 .proc_handler = proc_dointvec,
3318 },
3319 {
3320 .procname = "mtu_expires",
3321 .data = &ip_rt_mtu_expires,
3322 .maxlen = sizeof(int),
3323 .mode = 0644,
3324 .proc_handler = proc_dointvec_jiffies,
3325 },
3326 {
3327 .procname = "min_pmtu",
3328 .data = &ip_rt_min_pmtu,
3329 .maxlen = sizeof(int),
3330 .mode = 0644,
3331 .proc_handler = proc_dointvec_minmax,
3332 .extra1 = &ip_min_valid_pmtu,
3333 },
3334 {
3335 .procname = "min_adv_mss",
3336 .data = &ip_rt_min_advmss,
3337 .maxlen = sizeof(int),
3338 .mode = 0644,
3339 .proc_handler = proc_dointvec,
3340 },
3341 { }
3342 };
3343
3344 static const char ipv4_route_flush_procname[] = "flush";
3345
3346 static struct ctl_table ipv4_route_flush_table[] = {
3347 {
3348 .procname = ipv4_route_flush_procname,
3349 .maxlen = sizeof(int),
3350 .mode = 0200,
3351 .proc_handler = ipv4_sysctl_rtcache_flush,
3352 },
3353 { },
3354 };
3355
3356 static __net_init int sysctl_route_net_init(struct net *net)
3357 {
3358 struct ctl_table *tbl;
3359
3360 tbl = ipv4_route_flush_table;
3361 if (!net_eq(net, &init_net)) {
3362 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3363 if (!tbl)
3364 goto err_dup;
3365
3366 /* Don't export non-whitelisted sysctls to unprivileged users */
3367 if (net->user_ns != &init_user_ns) {
3368 if (tbl[0].procname != ipv4_route_flush_procname)
3369 tbl[0].procname = NULL;
3370 }
3371 }
3372 tbl[0].extra1 = net;
3373
3374 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3375 if (!net->ipv4.route_hdr)
3376 goto err_reg;
3377 return 0;
3378
3379 err_reg:
3380 if (tbl != ipv4_route_flush_table)
3381 kfree(tbl);
3382 err_dup:
3383 return -ENOMEM;
3384 }
3385
3386 static __net_exit void sysctl_route_net_exit(struct net *net)
3387 {
3388 struct ctl_table *tbl;
3389
3390 tbl = net->ipv4.route_hdr->ctl_table_arg;
3391 unregister_net_sysctl_table(net->ipv4.route_hdr);
3392 BUG_ON(tbl == ipv4_route_flush_table);
3393 kfree(tbl);
3394 }
3395
3396 static __net_initdata struct pernet_operations sysctl_route_ops = {
3397 .init = sysctl_route_net_init,
3398 .exit = sysctl_route_net_exit,
3399 };
3400 #endif
3401
3402 static __net_init int rt_genid_init(struct net *net)
3403 {
3404 atomic_set(&net->ipv4.rt_genid, 0);
3405 atomic_set(&net->fnhe_genid, 0);
3406 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3407 return 0;
3408 }
3409
3410 static __net_initdata struct pernet_operations rt_genid_ops = {
3411 .init = rt_genid_init,
3412 };
3413
3414 static int __net_init ipv4_inetpeer_init(struct net *net)
3415 {
3416 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3417
3418 if (!bp)
3419 return -ENOMEM;
3420 inet_peer_base_init(bp);
3421 net->ipv4.peers = bp;
3422 return 0;
3423 }
3424
3425 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3426 {
3427 struct inet_peer_base *bp = net->ipv4.peers;
3428
3429 net->ipv4.peers = NULL;
3430 inetpeer_invalidate_tree(bp);
3431 kfree(bp);
3432 }
3433
3434 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3435 .init = ipv4_inetpeer_init,
3436 .exit = ipv4_inetpeer_exit,
3437 };
3438
3439 #ifdef CONFIG_IP_ROUTE_CLASSID
3440 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3441 #endif /* CONFIG_IP_ROUTE_CLASSID */
3442
3443 int __init ip_rt_init(void)
3444 {
3445 int cpu;
3446
3447 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents),
3448 GFP_KERNEL);
3449 if (!ip_idents)
3450 panic("IP: failed to allocate ip_idents\n");
3451
3452 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3453
3454 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3455 if (!ip_tstamps)
3456 panic("IP: failed to allocate ip_tstamps\n");
3457
3458 for_each_possible_cpu(cpu) {
3459 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3460
3461 INIT_LIST_HEAD(&ul->head);
3462 spin_lock_init(&ul->lock);
3463 }
3464 #ifdef CONFIG_IP_ROUTE_CLASSID
3465 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3466 if (!ip_rt_acct)
3467 panic("IP: failed to allocate ip_rt_acct\n");
3468 #endif
3469
3470 ipv4_dst_ops.kmem_cachep =
3471 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3472 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3473
3474 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3475
3476 if (dst_entries_init(&ipv4_dst_ops) < 0)
3477 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3478
3479 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3480 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3481
3482 ipv4_dst_ops.gc_thresh = ~0;
3483 ip_rt_max_size = INT_MAX;
3484
3485 devinet_init();
3486 ip_fib_init();
3487
3488 if (ip_rt_proc_init())
3489 pr_err("Unable to create route proc files\n");
3490 #ifdef CONFIG_XFRM
3491 xfrm_init();
3492 xfrm4_init();
3493 #endif
3494 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3495 RTNL_FLAG_DOIT_UNLOCKED);
3496
3497 #ifdef CONFIG_SYSCTL
3498 register_pernet_subsys(&sysctl_route_ops);
3499 #endif
3500 register_pernet_subsys(&rt_genid_ops);
3501 register_pernet_subsys(&ipv4_inetpeer_ops);
3502 return 0;
3503 }
3504
3505 #ifdef CONFIG_SYSCTL
3506 /*
3507 * We really need to sanitize the damn ipv4 init order, then all
3508 * this nonsense will go away.
3509 */
3510 void __init ip_static_sysctl_init(void)
3511 {
3512 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3513 }
3514 #endif
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