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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/bitops.h>
65#include <linux/kernel.h>
66#include <linux/mm.h>
67#include <linux/memblock.h>
68#include <linux/socket.h>
69#include <linux/errno.h>
70#include <linux/in.h>
71#include <linux/inet.h>
72#include <linux/netdevice.h>
73#include <linux/proc_fs.h>
74#include <linux/init.h>
75#include <linux/skbuff.h>
76#include <linux/inetdevice.h>
77#include <linux/igmp.h>
78#include <linux/pkt_sched.h>
79#include <linux/mroute.h>
80#include <linux/netfilter_ipv4.h>
81#include <linux/random.h>
82#include <linux/rcupdate.h>
83#include <linux/slab.h>
84#include <linux/jhash.h>
85#include <net/dst.h>
86#include <net/dst_metadata.h>
87#include <net/inet_dscp.h>
88#include <net/net_namespace.h>
89#include <net/ip.h>
90#include <net/route.h>
91#include <net/inetpeer.h>
92#include <net/sock.h>
93#include <net/ip_fib.h>
94#include <net/nexthop.h>
95#include <net/tcp.h>
96#include <net/icmp.h>
97#include <net/xfrm.h>
98#include <net/lwtunnel.h>
99#include <net/netevent.h>
100#include <net/rtnetlink.h>
101#ifdef CONFIG_SYSCTL
102#include <linux/sysctl.h>
103#endif
104#include <net/secure_seq.h>
105#include <net/ip_tunnels.h>
106
107#include "fib_lookup.h"
108
109#define RT_GC_TIMEOUT (300*HZ)
110
111#define DEFAULT_MIN_PMTU (512 + 20 + 20)
112#define DEFAULT_MTU_EXPIRES (10 * 60 * HZ)
113#define DEFAULT_MIN_ADVMSS 256
114static int ip_rt_max_size;
115static int ip_rt_redirect_number __read_mostly = 9;
116static int ip_rt_redirect_load __read_mostly = HZ / 50;
117static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
118static int ip_rt_error_cost __read_mostly = HZ;
119static int ip_rt_error_burst __read_mostly = 5 * HZ;
120
121static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
122
123/*
124 * Interface to generic destination cache.
125 */
126
127INDIRECT_CALLABLE_SCOPE
128struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
129static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
130INDIRECT_CALLABLE_SCOPE
131unsigned int ipv4_mtu(const struct dst_entry *dst);
132static void ipv4_negative_advice(struct sock *sk,
133 struct dst_entry *dst);
134static void ipv4_link_failure(struct sk_buff *skb);
135static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
136 struct sk_buff *skb, u32 mtu,
137 bool confirm_neigh);
138static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
139 struct sk_buff *skb);
140static void ipv4_dst_destroy(struct dst_entry *dst);
141
142static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
143{
144 WARN_ON(1);
145 return NULL;
146}
147
148static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
149 struct sk_buff *skb,
150 const void *daddr);
151static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
152
153static struct dst_ops ipv4_dst_ops = {
154 .family = AF_INET,
155 .check = ipv4_dst_check,
156 .default_advmss = ipv4_default_advmss,
157 .mtu = ipv4_mtu,
158 .cow_metrics = ipv4_cow_metrics,
159 .destroy = ipv4_dst_destroy,
160 .negative_advice = ipv4_negative_advice,
161 .link_failure = ipv4_link_failure,
162 .update_pmtu = ip_rt_update_pmtu,
163 .redirect = ip_do_redirect,
164 .local_out = __ip_local_out,
165 .neigh_lookup = ipv4_neigh_lookup,
166 .confirm_neigh = ipv4_confirm_neigh,
167};
168
169#define ECN_OR_COST(class) TC_PRIO_##class
170
171const __u8 ip_tos2prio[16] = {
172 TC_PRIO_BESTEFFORT,
173 ECN_OR_COST(BESTEFFORT),
174 TC_PRIO_BESTEFFORT,
175 ECN_OR_COST(BESTEFFORT),
176 TC_PRIO_BULK,
177 ECN_OR_COST(BULK),
178 TC_PRIO_BULK,
179 ECN_OR_COST(BULK),
180 TC_PRIO_INTERACTIVE,
181 ECN_OR_COST(INTERACTIVE),
182 TC_PRIO_INTERACTIVE,
183 ECN_OR_COST(INTERACTIVE),
184 TC_PRIO_INTERACTIVE_BULK,
185 ECN_OR_COST(INTERACTIVE_BULK),
186 TC_PRIO_INTERACTIVE_BULK,
187 ECN_OR_COST(INTERACTIVE_BULK)
188};
189EXPORT_SYMBOL(ip_tos2prio);
190
191static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
192#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
193
194#ifdef CONFIG_PROC_FS
195static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
196{
197 if (*pos)
198 return NULL;
199 return SEQ_START_TOKEN;
200}
201
202static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
203{
204 ++*pos;
205 return NULL;
206}
207
208static void rt_cache_seq_stop(struct seq_file *seq, void *v)
209{
210}
211
212static int rt_cache_seq_show(struct seq_file *seq, void *v)
213{
214 if (v == SEQ_START_TOKEN)
215 seq_printf(seq, "%-127s\n",
216 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
217 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
218 "HHUptod\tSpecDst");
219 return 0;
220}
221
222static const struct seq_operations rt_cache_seq_ops = {
223 .start = rt_cache_seq_start,
224 .next = rt_cache_seq_next,
225 .stop = rt_cache_seq_stop,
226 .show = rt_cache_seq_show,
227};
228
229static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
230{
231 int cpu;
232
233 if (*pos == 0)
234 return SEQ_START_TOKEN;
235
236 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
237 if (!cpu_possible(cpu))
238 continue;
239 *pos = cpu+1;
240 return &per_cpu(rt_cache_stat, cpu);
241 }
242 return NULL;
243}
244
245static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
246{
247 int cpu;
248
249 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
250 if (!cpu_possible(cpu))
251 continue;
252 *pos = cpu+1;
253 return &per_cpu(rt_cache_stat, cpu);
254 }
255 (*pos)++;
256 return NULL;
257
258}
259
260static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
261{
262
263}
264
265static int rt_cpu_seq_show(struct seq_file *seq, void *v)
266{
267 struct rt_cache_stat *st = v;
268
269 if (v == SEQ_START_TOKEN) {
270 seq_puts(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");
271 return 0;
272 }
273
274 seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x "
275 "%08x %08x %08x %08x %08x %08x "
276 "%08x %08x %08x %08x\n",
277 dst_entries_get_slow(&ipv4_dst_ops),
278 0, /* st->in_hit */
279 st->in_slow_tot,
280 st->in_slow_mc,
281 st->in_no_route,
282 st->in_brd,
283 st->in_martian_dst,
284 st->in_martian_src,
285
286 0, /* st->out_hit */
287 st->out_slow_tot,
288 st->out_slow_mc,
289
290 0, /* st->gc_total */
291 0, /* st->gc_ignored */
292 0, /* st->gc_goal_miss */
293 0, /* st->gc_dst_overflow */
294 0, /* st->in_hlist_search */
295 0 /* st->out_hlist_search */
296 );
297 return 0;
298}
299
300static const struct seq_operations rt_cpu_seq_ops = {
301 .start = rt_cpu_seq_start,
302 .next = rt_cpu_seq_next,
303 .stop = rt_cpu_seq_stop,
304 .show = rt_cpu_seq_show,
305};
306
307#ifdef CONFIG_IP_ROUTE_CLASSID
308static int rt_acct_proc_show(struct seq_file *m, void *v)
309{
310 struct ip_rt_acct *dst, *src;
311 unsigned int i, j;
312
313 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
314 if (!dst)
315 return -ENOMEM;
316
317 for_each_possible_cpu(i) {
318 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
319 for (j = 0; j < 256; j++) {
320 dst[j].o_bytes += src[j].o_bytes;
321 dst[j].o_packets += src[j].o_packets;
322 dst[j].i_bytes += src[j].i_bytes;
323 dst[j].i_packets += src[j].i_packets;
324 }
325 }
326
327 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
328 kfree(dst);
329 return 0;
330}
331#endif
332
333static int __net_init ip_rt_do_proc_init(struct net *net)
334{
335 struct proc_dir_entry *pde;
336
337 pde = proc_create_seq("rt_cache", 0444, net->proc_net,
338 &rt_cache_seq_ops);
339 if (!pde)
340 goto err1;
341
342 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
343 &rt_cpu_seq_ops);
344 if (!pde)
345 goto err2;
346
347#ifdef CONFIG_IP_ROUTE_CLASSID
348 pde = proc_create_single("rt_acct", 0, net->proc_net,
349 rt_acct_proc_show);
350 if (!pde)
351 goto err3;
352#endif
353 return 0;
354
355#ifdef CONFIG_IP_ROUTE_CLASSID
356err3:
357 remove_proc_entry("rt_cache", net->proc_net_stat);
358#endif
359err2:
360 remove_proc_entry("rt_cache", net->proc_net);
361err1:
362 return -ENOMEM;
363}
364
365static void __net_exit ip_rt_do_proc_exit(struct net *net)
366{
367 remove_proc_entry("rt_cache", net->proc_net_stat);
368 remove_proc_entry("rt_cache", net->proc_net);
369#ifdef CONFIG_IP_ROUTE_CLASSID
370 remove_proc_entry("rt_acct", net->proc_net);
371#endif
372}
373
374static struct pernet_operations ip_rt_proc_ops __net_initdata = {
375 .init = ip_rt_do_proc_init,
376 .exit = ip_rt_do_proc_exit,
377};
378
379static int __init ip_rt_proc_init(void)
380{
381 return register_pernet_subsys(&ip_rt_proc_ops);
382}
383
384#else
385static inline int ip_rt_proc_init(void)
386{
387 return 0;
388}
389#endif /* CONFIG_PROC_FS */
390
391static inline bool rt_is_expired(const struct rtable *rth)
392{
393 bool res;
394
395 rcu_read_lock();
396 res = rth->rt_genid != rt_genid_ipv4(dev_net_rcu(rth->dst.dev));
397 rcu_read_unlock();
398
399 return res;
400}
401
402void rt_cache_flush(struct net *net)
403{
404 rt_genid_bump_ipv4(net);
405}
406
407static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
408 struct sk_buff *skb,
409 const void *daddr)
410{
411 const struct rtable *rt = container_of(dst, struct rtable, dst);
412 struct net_device *dev = dst->dev;
413 struct neighbour *n;
414
415 rcu_read_lock();
416
417 if (likely(rt->rt_gw_family == AF_INET)) {
418 n = ip_neigh_gw4(dev, rt->rt_gw4);
419 } else if (rt->rt_gw_family == AF_INET6) {
420 n = ip_neigh_gw6(dev, &rt->rt_gw6);
421 } else {
422 __be32 pkey;
423
424 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
425 n = ip_neigh_gw4(dev, pkey);
426 }
427
428 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
429 n = NULL;
430
431 rcu_read_unlock();
432
433 return n;
434}
435
436static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
437{
438 const struct rtable *rt = container_of(dst, struct rtable, dst);
439 struct net_device *dev = dst->dev;
440 const __be32 *pkey = daddr;
441
442 if (rt->rt_gw_family == AF_INET) {
443 pkey = (const __be32 *)&rt->rt_gw4;
444 } else if (rt->rt_gw_family == AF_INET6) {
445 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
446 } else if (!daddr ||
447 (rt->rt_flags &
448 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
449 return;
450 }
451 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
452}
453
454/* Hash tables of size 2048..262144 depending on RAM size.
455 * Each bucket uses 8 bytes.
456 */
457static u32 ip_idents_mask __read_mostly;
458static atomic_t *ip_idents __read_mostly;
459static u32 *ip_tstamps __read_mostly;
460
461/* In order to protect privacy, we add a perturbation to identifiers
462 * if one generator is seldom used. This makes hard for an attacker
463 * to infer how many packets were sent between two points in time.
464 */
465static u32 ip_idents_reserve(u32 hash, int segs)
466{
467 u32 bucket, old, now = (u32)jiffies;
468 atomic_t *p_id;
469 u32 *p_tstamp;
470 u32 delta = 0;
471
472 bucket = hash & ip_idents_mask;
473 p_tstamp = ip_tstamps + bucket;
474 p_id = ip_idents + bucket;
475 old = READ_ONCE(*p_tstamp);
476
477 if (old != now && cmpxchg(p_tstamp, old, now) == old)
478 delta = get_random_u32_below(now - old);
479
480 /* If UBSAN reports an error there, please make sure your compiler
481 * supports -fno-strict-overflow before reporting it that was a bug
482 * in UBSAN, and it has been fixed in GCC-8.
483 */
484 return atomic_add_return(segs + delta, p_id) - segs;
485}
486
487void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
488{
489 u32 hash, id;
490
491 /* Note the following code is not safe, but this is okay. */
492 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
493 get_random_bytes(&net->ipv4.ip_id_key,
494 sizeof(net->ipv4.ip_id_key));
495
496 hash = siphash_3u32((__force u32)iph->daddr,
497 (__force u32)iph->saddr,
498 iph->protocol,
499 &net->ipv4.ip_id_key);
500 id = ip_idents_reserve(hash, segs);
501 iph->id = htons(id);
502}
503EXPORT_SYMBOL(__ip_select_ident);
504
505static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
506 const struct sock *sk, const struct iphdr *iph,
507 int oif, __u8 tos, u8 prot, u32 mark,
508 int flow_flags)
509{
510 __u8 scope = RT_SCOPE_UNIVERSE;
511
512 if (sk) {
513 oif = sk->sk_bound_dev_if;
514 mark = READ_ONCE(sk->sk_mark);
515 tos = ip_sock_rt_tos(sk);
516 scope = ip_sock_rt_scope(sk);
517 prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW :
518 sk->sk_protocol;
519 }
520
521 flowi4_init_output(fl4, oif, mark, tos & INET_DSCP_MASK, scope,
522 prot, flow_flags, iph->daddr, iph->saddr, 0, 0,
523 sock_net_uid(net, sk));
524}
525
526static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
527 const struct sock *sk)
528{
529 const struct net *net = dev_net(skb->dev);
530 const struct iphdr *iph = ip_hdr(skb);
531 int oif = skb->dev->ifindex;
532 u8 prot = iph->protocol;
533 u32 mark = skb->mark;
534 __u8 tos = iph->tos;
535
536 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
537}
538
539static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
540{
541 const struct inet_sock *inet = inet_sk(sk);
542 const struct ip_options_rcu *inet_opt;
543 __be32 daddr = inet->inet_daddr;
544
545 rcu_read_lock();
546 inet_opt = rcu_dereference(inet->inet_opt);
547 if (inet_opt && inet_opt->opt.srr)
548 daddr = inet_opt->opt.faddr;
549 flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark),
550 ip_sock_rt_tos(sk),
551 ip_sock_rt_scope(sk),
552 inet_test_bit(HDRINCL, sk) ?
553 IPPROTO_RAW : sk->sk_protocol,
554 inet_sk_flowi_flags(sk),
555 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
556 rcu_read_unlock();
557}
558
559static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
560 const struct sk_buff *skb)
561{
562 if (skb)
563 build_skb_flow_key(fl4, skb, sk);
564 else
565 build_sk_flow_key(fl4, sk);
566}
567
568static DEFINE_SPINLOCK(fnhe_lock);
569
570static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
571{
572 struct rtable *rt;
573
574 rt = rcu_dereference(fnhe->fnhe_rth_input);
575 if (rt) {
576 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
577 dst_dev_put(&rt->dst);
578 dst_release(&rt->dst);
579 }
580 rt = rcu_dereference(fnhe->fnhe_rth_output);
581 if (rt) {
582 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
583 dst_dev_put(&rt->dst);
584 dst_release(&rt->dst);
585 }
586}
587
588static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
589{
590 struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
591 struct fib_nh_exception *fnhe, *oldest = NULL;
592
593 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
594 fnhe = rcu_dereference_protected(*fnhe_p,
595 lockdep_is_held(&fnhe_lock));
596 if (!fnhe)
597 break;
598 if (!oldest ||
599 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
600 oldest = fnhe;
601 oldest_p = fnhe_p;
602 }
603 }
604 fnhe_flush_routes(oldest);
605 *oldest_p = oldest->fnhe_next;
606 kfree_rcu(oldest, rcu);
607}
608
609static u32 fnhe_hashfun(__be32 daddr)
610{
611 static siphash_aligned_key_t fnhe_hash_key;
612 u64 hval;
613
614 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
615 hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key);
616 return hash_64(hval, FNHE_HASH_SHIFT);
617}
618
619static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
620{
621 rt->rt_pmtu = fnhe->fnhe_pmtu;
622 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
623 rt->dst.expires = fnhe->fnhe_expires;
624
625 if (fnhe->fnhe_gw) {
626 rt->rt_flags |= RTCF_REDIRECTED;
627 rt->rt_uses_gateway = 1;
628 rt->rt_gw_family = AF_INET;
629 rt->rt_gw4 = fnhe->fnhe_gw;
630 }
631}
632
633static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
634 __be32 gw, u32 pmtu, bool lock,
635 unsigned long expires)
636{
637 struct fnhe_hash_bucket *hash;
638 struct fib_nh_exception *fnhe;
639 struct rtable *rt;
640 u32 genid, hval;
641 unsigned int i;
642 int depth;
643
644 genid = fnhe_genid(dev_net(nhc->nhc_dev));
645 hval = fnhe_hashfun(daddr);
646
647 spin_lock_bh(&fnhe_lock);
648
649 hash = rcu_dereference(nhc->nhc_exceptions);
650 if (!hash) {
651 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
652 if (!hash)
653 goto out_unlock;
654 rcu_assign_pointer(nhc->nhc_exceptions, hash);
655 }
656
657 hash += hval;
658
659 depth = 0;
660 for (fnhe = rcu_dereference(hash->chain); fnhe;
661 fnhe = rcu_dereference(fnhe->fnhe_next)) {
662 if (fnhe->fnhe_daddr == daddr)
663 break;
664 depth++;
665 }
666
667 if (fnhe) {
668 if (fnhe->fnhe_genid != genid)
669 fnhe->fnhe_genid = genid;
670 if (gw)
671 fnhe->fnhe_gw = gw;
672 if (pmtu) {
673 fnhe->fnhe_pmtu = pmtu;
674 fnhe->fnhe_mtu_locked = lock;
675 }
676 fnhe->fnhe_expires = max(1UL, expires);
677 /* Update all cached dsts too */
678 rt = rcu_dereference(fnhe->fnhe_rth_input);
679 if (rt)
680 fill_route_from_fnhe(rt, fnhe);
681 rt = rcu_dereference(fnhe->fnhe_rth_output);
682 if (rt)
683 fill_route_from_fnhe(rt, fnhe);
684 } else {
685 /* Randomize max depth to avoid some side channels attacks. */
686 int max_depth = FNHE_RECLAIM_DEPTH +
687 get_random_u32_below(FNHE_RECLAIM_DEPTH);
688
689 while (depth > max_depth) {
690 fnhe_remove_oldest(hash);
691 depth--;
692 }
693
694 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
695 if (!fnhe)
696 goto out_unlock;
697
698 fnhe->fnhe_next = hash->chain;
699
700 fnhe->fnhe_genid = genid;
701 fnhe->fnhe_daddr = daddr;
702 fnhe->fnhe_gw = gw;
703 fnhe->fnhe_pmtu = pmtu;
704 fnhe->fnhe_mtu_locked = lock;
705 fnhe->fnhe_expires = max(1UL, expires);
706
707 rcu_assign_pointer(hash->chain, fnhe);
708
709 /* Exception created; mark the cached routes for the nexthop
710 * stale, so anyone caching it rechecks if this exception
711 * applies to them.
712 */
713 rt = rcu_dereference(nhc->nhc_rth_input);
714 if (rt)
715 rt->dst.obsolete = DST_OBSOLETE_KILL;
716
717 for_each_possible_cpu(i) {
718 struct rtable __rcu **prt;
719
720 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
721 rt = rcu_dereference(*prt);
722 if (rt)
723 rt->dst.obsolete = DST_OBSOLETE_KILL;
724 }
725 }
726
727 fnhe->fnhe_stamp = jiffies;
728
729out_unlock:
730 spin_unlock_bh(&fnhe_lock);
731}
732
733static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
734 bool kill_route)
735{
736 __be32 new_gw = icmp_hdr(skb)->un.gateway;
737 __be32 old_gw = ip_hdr(skb)->saddr;
738 struct net_device *dev = skb->dev;
739 struct in_device *in_dev;
740 struct fib_result res;
741 struct neighbour *n;
742 struct net *net;
743
744 switch (icmp_hdr(skb)->code & 7) {
745 case ICMP_REDIR_NET:
746 case ICMP_REDIR_NETTOS:
747 case ICMP_REDIR_HOST:
748 case ICMP_REDIR_HOSTTOS:
749 break;
750
751 default:
752 return;
753 }
754
755 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
756 return;
757
758 in_dev = __in_dev_get_rcu(dev);
759 if (!in_dev)
760 return;
761
762 net = dev_net(dev);
763 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
764 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
765 ipv4_is_zeronet(new_gw))
766 goto reject_redirect;
767
768 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
769 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
770 goto reject_redirect;
771 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
772 goto reject_redirect;
773 } else {
774 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
775 goto reject_redirect;
776 }
777
778 n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw);
779 if (!n)
780 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
781 if (!IS_ERR(n)) {
782 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
783 neigh_event_send(n, NULL);
784 } else {
785 if (fib_lookup(net, fl4, &res, 0) == 0) {
786 struct fib_nh_common *nhc;
787
788 fib_select_path(net, &res, fl4, skb);
789 nhc = FIB_RES_NHC(res);
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
802reject_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
818static 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 prot = iph->protocol;
826 u32 mark = skb->mark;
827 __u8 tos = iph->tos;
828
829 rt = dst_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
835static void ipv4_negative_advice(struct sock *sk,
836 struct dst_entry *dst)
837{
838 struct rtable *rt = dst_rtable(dst);
839
840 if ((dst->obsolete > 0) ||
841 (rt->rt_flags & RTCF_REDIRECTED) ||
842 rt->dst.expires)
843 sk_dst_reset(sk);
844}
845
846/*
847 * Algorithm:
848 * 1. The first ip_rt_redirect_number redirects are sent
849 * with exponential backoff, then we stop sending them at all,
850 * assuming that the host ignores our redirects.
851 * 2. If we did not see packets requiring redirects
852 * during ip_rt_redirect_silence, we assume that the host
853 * forgot redirected route and start to send redirects again.
854 *
855 * This algorithm is much cheaper and more intelligent than dumb load limiting
856 * in icmp.c.
857 *
858 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
859 * and "frag. need" (breaks PMTU discovery) in icmp.c.
860 */
861
862void ip_rt_send_redirect(struct sk_buff *skb)
863{
864 struct rtable *rt = skb_rtable(skb);
865 struct in_device *in_dev;
866 struct inet_peer *peer;
867 struct net *net;
868 int log_martians;
869 int vif;
870
871 rcu_read_lock();
872 in_dev = __in_dev_get_rcu(rt->dst.dev);
873 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
874 rcu_read_unlock();
875 return;
876 }
877 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
878 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
879
880 net = dev_net(rt->dst.dev);
881 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif);
882 if (!peer) {
883 rcu_read_unlock();
884 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
885 rt_nexthop(rt, ip_hdr(skb)->daddr));
886 return;
887 }
888
889 /* No redirected packets during ip_rt_redirect_silence;
890 * reset the algorithm.
891 */
892 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
893 peer->rate_tokens = 0;
894 peer->n_redirects = 0;
895 }
896
897 /* Too many ignored redirects; do not send anything
898 * set dst.rate_last to the last seen redirected packet.
899 */
900 if (peer->n_redirects >= ip_rt_redirect_number) {
901 peer->rate_last = jiffies;
902 goto out_unlock;
903 }
904
905 /* Check for load limit; set rate_last to the latest sent
906 * redirect.
907 */
908 if (peer->n_redirects == 0 ||
909 time_after(jiffies,
910 (peer->rate_last +
911 (ip_rt_redirect_load << peer->n_redirects)))) {
912 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
913
914 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
915 peer->rate_last = jiffies;
916 ++peer->n_redirects;
917 if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians &&
918 peer->n_redirects == ip_rt_redirect_number)
919 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
920 &ip_hdr(skb)->saddr, inet_iif(skb),
921 &ip_hdr(skb)->daddr, &gw);
922 }
923out_unlock:
924 rcu_read_unlock();
925}
926
927static int ip_error(struct sk_buff *skb)
928{
929 struct rtable *rt = skb_rtable(skb);
930 struct net_device *dev = skb->dev;
931 struct in_device *in_dev;
932 struct inet_peer *peer;
933 unsigned long now;
934 struct net *net;
935 SKB_DR(reason);
936 bool send;
937 int code;
938
939 if (netif_is_l3_master(skb->dev)) {
940 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
941 if (!dev)
942 goto out;
943 }
944
945 in_dev = __in_dev_get_rcu(dev);
946
947 /* IP on this device is disabled. */
948 if (!in_dev)
949 goto out;
950
951 net = dev_net(rt->dst.dev);
952 if (!IN_DEV_FORWARD(in_dev)) {
953 switch (rt->dst.error) {
954 case EHOSTUNREACH:
955 SKB_DR_SET(reason, IP_INADDRERRORS);
956 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
957 break;
958
959 case ENETUNREACH:
960 SKB_DR_SET(reason, IP_INNOROUTES);
961 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
962 break;
963 }
964 goto out;
965 }
966
967 switch (rt->dst.error) {
968 case EINVAL:
969 default:
970 goto out;
971 case EHOSTUNREACH:
972 code = ICMP_HOST_UNREACH;
973 break;
974 case ENETUNREACH:
975 code = ICMP_NET_UNREACH;
976 SKB_DR_SET(reason, IP_INNOROUTES);
977 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
978 break;
979 case EACCES:
980 code = ICMP_PKT_FILTERED;
981 break;
982 }
983
984 rcu_read_lock();
985 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
986 l3mdev_master_ifindex_rcu(skb->dev));
987 send = true;
988 if (peer) {
989 now = jiffies;
990 peer->rate_tokens += now - peer->rate_last;
991 if (peer->rate_tokens > ip_rt_error_burst)
992 peer->rate_tokens = ip_rt_error_burst;
993 peer->rate_last = now;
994 if (peer->rate_tokens >= ip_rt_error_cost)
995 peer->rate_tokens -= ip_rt_error_cost;
996 else
997 send = false;
998 }
999 rcu_read_unlock();
1000
1001 if (send)
1002 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1003
1004out: kfree_skb_reason(skb, reason);
1005 return 0;
1006}
1007
1008static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1009{
1010 struct dst_entry *dst = &rt->dst;
1011 struct fib_result res;
1012 bool lock = false;
1013 struct net *net;
1014 u32 old_mtu;
1015
1016 if (ip_mtu_locked(dst))
1017 return;
1018
1019 old_mtu = ipv4_mtu(dst);
1020 if (old_mtu < mtu)
1021 return;
1022
1023 rcu_read_lock();
1024 net = dev_net_rcu(dst->dev);
1025 if (mtu < net->ipv4.ip_rt_min_pmtu) {
1026 lock = true;
1027 mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
1028 }
1029
1030 if (rt->rt_pmtu == mtu && !lock &&
1031 time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
1032 goto out;
1033
1034 if (fib_lookup(net, fl4, &res, 0) == 0) {
1035 struct fib_nh_common *nhc;
1036
1037 fib_select_path(net, &res, fl4, NULL);
1038#ifdef CONFIG_IP_ROUTE_MULTIPATH
1039 if (fib_info_num_path(res.fi) > 1) {
1040 int nhsel;
1041
1042 for (nhsel = 0; nhsel < fib_info_num_path(res.fi); nhsel++) {
1043 nhc = fib_info_nhc(res.fi, nhsel);
1044 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1045 jiffies + net->ipv4.ip_rt_mtu_expires);
1046 }
1047 goto out;
1048 }
1049#endif /* CONFIG_IP_ROUTE_MULTIPATH */
1050 nhc = FIB_RES_NHC(res);
1051 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1052 jiffies + net->ipv4.ip_rt_mtu_expires);
1053 }
1054out:
1055 rcu_read_unlock();
1056}
1057
1058static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1059 struct sk_buff *skb, u32 mtu,
1060 bool confirm_neigh)
1061{
1062 struct rtable *rt = dst_rtable(dst);
1063 struct flowi4 fl4;
1064
1065 ip_rt_build_flow_key(&fl4, sk, skb);
1066
1067 /* Don't make lookup fail for bridged encapsulations */
1068 if (skb && netif_is_any_bridge_port(skb->dev))
1069 fl4.flowi4_oif = 0;
1070
1071 __ip_rt_update_pmtu(rt, &fl4, mtu);
1072}
1073
1074void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1075 int oif, u8 protocol)
1076{
1077 const struct iphdr *iph = (const struct iphdr *)skb->data;
1078 struct flowi4 fl4;
1079 struct rtable *rt;
1080 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1081
1082 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, mark,
1083 0);
1084 rt = __ip_route_output_key(net, &fl4);
1085 if (!IS_ERR(rt)) {
1086 __ip_rt_update_pmtu(rt, &fl4, mtu);
1087 ip_rt_put(rt);
1088 }
1089}
1090EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1091
1092static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1093{
1094 const struct iphdr *iph = (const struct iphdr *)skb->data;
1095 struct flowi4 fl4;
1096 struct rtable *rt;
1097
1098 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1099
1100 if (!fl4.flowi4_mark)
1101 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1102
1103 rt = __ip_route_output_key(sock_net(sk), &fl4);
1104 if (!IS_ERR(rt)) {
1105 __ip_rt_update_pmtu(rt, &fl4, mtu);
1106 ip_rt_put(rt);
1107 }
1108}
1109
1110void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1111{
1112 const struct iphdr *iph = (const struct iphdr *)skb->data;
1113 struct flowi4 fl4;
1114 struct rtable *rt;
1115 struct dst_entry *odst = NULL;
1116 bool new = false;
1117 struct net *net = sock_net(sk);
1118
1119 bh_lock_sock(sk);
1120
1121 if (!ip_sk_accept_pmtu(sk))
1122 goto out;
1123
1124 odst = sk_dst_get(sk);
1125
1126 if (sock_owned_by_user(sk) || !odst) {
1127 __ipv4_sk_update_pmtu(skb, sk, mtu);
1128 goto out;
1129 }
1130
1131 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1132
1133 rt = dst_rtable(odst);
1134 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1135 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1136 if (IS_ERR(rt))
1137 goto out;
1138
1139 new = true;
1140 }
1141
1142 __ip_rt_update_pmtu(dst_rtable(xfrm_dst_path(&rt->dst)), &fl4, mtu);
1143
1144 if (!dst_check(&rt->dst, 0)) {
1145 if (new)
1146 dst_release(&rt->dst);
1147
1148 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1149 if (IS_ERR(rt))
1150 goto out;
1151
1152 new = true;
1153 }
1154
1155 if (new)
1156 sk_dst_set(sk, &rt->dst);
1157
1158out:
1159 bh_unlock_sock(sk);
1160 dst_release(odst);
1161}
1162EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1163
1164void ipv4_redirect(struct sk_buff *skb, struct net *net,
1165 int oif, u8 protocol)
1166{
1167 const struct iphdr *iph = (const struct iphdr *)skb->data;
1168 struct flowi4 fl4;
1169 struct rtable *rt;
1170
1171 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, 0, 0);
1172 rt = __ip_route_output_key(net, &fl4);
1173 if (!IS_ERR(rt)) {
1174 __ip_do_redirect(rt, skb, &fl4, false);
1175 ip_rt_put(rt);
1176 }
1177}
1178EXPORT_SYMBOL_GPL(ipv4_redirect);
1179
1180void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1181{
1182 const struct iphdr *iph = (const struct iphdr *)skb->data;
1183 struct flowi4 fl4;
1184 struct rtable *rt;
1185 struct net *net = sock_net(sk);
1186
1187 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1188 rt = __ip_route_output_key(net, &fl4);
1189 if (!IS_ERR(rt)) {
1190 __ip_do_redirect(rt, skb, &fl4, false);
1191 ip_rt_put(rt);
1192 }
1193}
1194EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1195
1196INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1197 u32 cookie)
1198{
1199 struct rtable *rt = dst_rtable(dst);
1200
1201 /* All IPV4 dsts are created with ->obsolete set to the value
1202 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1203 * into this function always.
1204 *
1205 * When a PMTU/redirect information update invalidates a route,
1206 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1207 * DST_OBSOLETE_DEAD.
1208 */
1209 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1210 return NULL;
1211 return dst;
1212}
1213EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1214
1215static void ipv4_send_dest_unreach(struct sk_buff *skb)
1216{
1217 struct net_device *dev;
1218 struct ip_options opt;
1219 int res;
1220
1221 /* Recompile ip options since IPCB may not be valid anymore.
1222 * Also check we have a reasonable ipv4 header.
1223 */
1224 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1225 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1226 return;
1227
1228 memset(&opt, 0, sizeof(opt));
1229 if (ip_hdr(skb)->ihl > 5) {
1230 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1231 return;
1232 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1233
1234 rcu_read_lock();
1235 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
1236 res = __ip_options_compile(dev_net(dev), &opt, skb, NULL);
1237 rcu_read_unlock();
1238
1239 if (res)
1240 return;
1241 }
1242 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1243}
1244
1245static void ipv4_link_failure(struct sk_buff *skb)
1246{
1247 struct rtable *rt;
1248
1249 ipv4_send_dest_unreach(skb);
1250
1251 rt = skb_rtable(skb);
1252 if (rt)
1253 dst_set_expires(&rt->dst, 0);
1254}
1255
1256static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1257{
1258 pr_debug("%s: %pI4 -> %pI4, %s\n",
1259 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1260 skb->dev ? skb->dev->name : "?");
1261 kfree_skb(skb);
1262 WARN_ON(1);
1263 return 0;
1264}
1265
1266/*
1267 * We do not cache source address of outgoing interface,
1268 * because it is used only by IP RR, TS and SRR options,
1269 * so that it out of fast path.
1270 *
1271 * BTW remember: "addr" is allowed to be not aligned
1272 * in IP options!
1273 */
1274
1275void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1276{
1277 __be32 src;
1278
1279 if (rt_is_output_route(rt))
1280 src = ip_hdr(skb)->saddr;
1281 else {
1282 struct fib_result res;
1283 struct iphdr *iph = ip_hdr(skb);
1284 struct flowi4 fl4 = {
1285 .daddr = iph->daddr,
1286 .saddr = iph->saddr,
1287 .flowi4_tos = inet_dscp_to_dsfield(ip4h_dscp(iph)),
1288 .flowi4_oif = rt->dst.dev->ifindex,
1289 .flowi4_iif = skb->dev->ifindex,
1290 .flowi4_mark = skb->mark,
1291 };
1292
1293 rcu_read_lock();
1294 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1295 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1296 else
1297 src = inet_select_addr(rt->dst.dev,
1298 rt_nexthop(rt, iph->daddr),
1299 RT_SCOPE_UNIVERSE);
1300 rcu_read_unlock();
1301 }
1302 memcpy(addr, &src, 4);
1303}
1304
1305#ifdef CONFIG_IP_ROUTE_CLASSID
1306static void set_class_tag(struct rtable *rt, u32 tag)
1307{
1308 if (!(rt->dst.tclassid & 0xFFFF))
1309 rt->dst.tclassid |= tag & 0xFFFF;
1310 if (!(rt->dst.tclassid & 0xFFFF0000))
1311 rt->dst.tclassid |= tag & 0xFFFF0000;
1312}
1313#endif
1314
1315static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1316{
1317 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1318 unsigned int advmss;
1319 struct net *net;
1320
1321 rcu_read_lock();
1322 net = dev_net_rcu(dst->dev);
1323 advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1324 net->ipv4.ip_rt_min_advmss);
1325 rcu_read_unlock();
1326
1327 return min(advmss, IPV4_MAX_PMTU - header_size);
1328}
1329
1330INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1331{
1332 return ip_dst_mtu_maybe_forward(dst, false);
1333}
1334EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1335
1336static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1337{
1338 struct fnhe_hash_bucket *hash;
1339 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1340 u32 hval = fnhe_hashfun(daddr);
1341
1342 spin_lock_bh(&fnhe_lock);
1343
1344 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1345 lockdep_is_held(&fnhe_lock));
1346 hash += hval;
1347
1348 fnhe_p = &hash->chain;
1349 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1350 while (fnhe) {
1351 if (fnhe->fnhe_daddr == daddr) {
1352 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1353 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1354 /* set fnhe_daddr to 0 to ensure it won't bind with
1355 * new dsts in rt_bind_exception().
1356 */
1357 fnhe->fnhe_daddr = 0;
1358 fnhe_flush_routes(fnhe);
1359 kfree_rcu(fnhe, rcu);
1360 break;
1361 }
1362 fnhe_p = &fnhe->fnhe_next;
1363 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1364 lockdep_is_held(&fnhe_lock));
1365 }
1366
1367 spin_unlock_bh(&fnhe_lock);
1368}
1369
1370static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1371 __be32 daddr)
1372{
1373 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1374 struct fib_nh_exception *fnhe;
1375 u32 hval;
1376
1377 if (!hash)
1378 return NULL;
1379
1380 hval = fnhe_hashfun(daddr);
1381
1382 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1383 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1384 if (fnhe->fnhe_daddr == daddr) {
1385 if (fnhe->fnhe_expires &&
1386 time_after(jiffies, fnhe->fnhe_expires)) {
1387 ip_del_fnhe(nhc, daddr);
1388 break;
1389 }
1390 return fnhe;
1391 }
1392 }
1393 return NULL;
1394}
1395
1396/* MTU selection:
1397 * 1. mtu on route is locked - use it
1398 * 2. mtu from nexthop exception
1399 * 3. mtu from egress device
1400 */
1401
1402u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1403{
1404 struct fib_nh_common *nhc = res->nhc;
1405 struct net_device *dev = nhc->nhc_dev;
1406 struct fib_info *fi = res->fi;
1407 u32 mtu = 0;
1408
1409 if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) ||
1410 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1411 mtu = fi->fib_mtu;
1412
1413 if (likely(!mtu)) {
1414 struct fib_nh_exception *fnhe;
1415
1416 fnhe = find_exception(nhc, daddr);
1417 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1418 mtu = fnhe->fnhe_pmtu;
1419 }
1420
1421 if (likely(!mtu))
1422 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1423
1424 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1425}
1426
1427static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1428 __be32 daddr, const bool do_cache)
1429{
1430 bool ret = false;
1431
1432 spin_lock_bh(&fnhe_lock);
1433
1434 if (daddr == fnhe->fnhe_daddr) {
1435 struct rtable __rcu **porig;
1436 struct rtable *orig;
1437 int genid = fnhe_genid(dev_net(rt->dst.dev));
1438
1439 if (rt_is_input_route(rt))
1440 porig = &fnhe->fnhe_rth_input;
1441 else
1442 porig = &fnhe->fnhe_rth_output;
1443 orig = rcu_dereference(*porig);
1444
1445 if (fnhe->fnhe_genid != genid) {
1446 fnhe->fnhe_genid = genid;
1447 fnhe->fnhe_gw = 0;
1448 fnhe->fnhe_pmtu = 0;
1449 fnhe->fnhe_expires = 0;
1450 fnhe->fnhe_mtu_locked = false;
1451 fnhe_flush_routes(fnhe);
1452 orig = NULL;
1453 }
1454 fill_route_from_fnhe(rt, fnhe);
1455 if (!rt->rt_gw4) {
1456 rt->rt_gw4 = daddr;
1457 rt->rt_gw_family = AF_INET;
1458 }
1459
1460 if (do_cache) {
1461 dst_hold(&rt->dst);
1462 rcu_assign_pointer(*porig, rt);
1463 if (orig) {
1464 dst_dev_put(&orig->dst);
1465 dst_release(&orig->dst);
1466 }
1467 ret = true;
1468 }
1469
1470 fnhe->fnhe_stamp = jiffies;
1471 }
1472 spin_unlock_bh(&fnhe_lock);
1473
1474 return ret;
1475}
1476
1477static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1478{
1479 struct rtable *orig, *prev, **p;
1480 bool ret = true;
1481
1482 if (rt_is_input_route(rt)) {
1483 p = (struct rtable **)&nhc->nhc_rth_input;
1484 } else {
1485 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1486 }
1487 orig = *p;
1488
1489 /* hold dst before doing cmpxchg() to avoid race condition
1490 * on this dst
1491 */
1492 dst_hold(&rt->dst);
1493 prev = cmpxchg(p, orig, rt);
1494 if (prev == orig) {
1495 if (orig) {
1496 rt_add_uncached_list(orig);
1497 dst_release(&orig->dst);
1498 }
1499 } else {
1500 dst_release(&rt->dst);
1501 ret = false;
1502 }
1503
1504 return ret;
1505}
1506
1507struct uncached_list {
1508 spinlock_t lock;
1509 struct list_head head;
1510};
1511
1512static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1513
1514void rt_add_uncached_list(struct rtable *rt)
1515{
1516 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1517
1518 rt->dst.rt_uncached_list = ul;
1519
1520 spin_lock_bh(&ul->lock);
1521 list_add_tail(&rt->dst.rt_uncached, &ul->head);
1522 spin_unlock_bh(&ul->lock);
1523}
1524
1525void rt_del_uncached_list(struct rtable *rt)
1526{
1527 if (!list_empty(&rt->dst.rt_uncached)) {
1528 struct uncached_list *ul = rt->dst.rt_uncached_list;
1529
1530 spin_lock_bh(&ul->lock);
1531 list_del_init(&rt->dst.rt_uncached);
1532 spin_unlock_bh(&ul->lock);
1533 }
1534}
1535
1536static void ipv4_dst_destroy(struct dst_entry *dst)
1537{
1538 ip_dst_metrics_put(dst);
1539 rt_del_uncached_list(dst_rtable(dst));
1540}
1541
1542void rt_flush_dev(struct net_device *dev)
1543{
1544 struct rtable *rt, *safe;
1545 int cpu;
1546
1547 for_each_possible_cpu(cpu) {
1548 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1549
1550 if (list_empty(&ul->head))
1551 continue;
1552
1553 spin_lock_bh(&ul->lock);
1554 list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) {
1555 if (rt->dst.dev != dev)
1556 continue;
1557 rt->dst.dev = blackhole_netdev;
1558 netdev_ref_replace(dev, blackhole_netdev,
1559 &rt->dst.dev_tracker, GFP_ATOMIC);
1560 list_del_init(&rt->dst.rt_uncached);
1561 }
1562 spin_unlock_bh(&ul->lock);
1563 }
1564}
1565
1566static bool rt_cache_valid(const struct rtable *rt)
1567{
1568 return rt &&
1569 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1570 !rt_is_expired(rt);
1571}
1572
1573static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1574 const struct fib_result *res,
1575 struct fib_nh_exception *fnhe,
1576 struct fib_info *fi, u16 type, u32 itag,
1577 const bool do_cache)
1578{
1579 bool cached = false;
1580
1581 if (fi) {
1582 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1583
1584 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1585 rt->rt_uses_gateway = 1;
1586 rt->rt_gw_family = nhc->nhc_gw_family;
1587 /* only INET and INET6 are supported */
1588 if (likely(nhc->nhc_gw_family == AF_INET))
1589 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1590 else
1591 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1592 }
1593
1594 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1595
1596#ifdef CONFIG_IP_ROUTE_CLASSID
1597 if (nhc->nhc_family == AF_INET) {
1598 struct fib_nh *nh;
1599
1600 nh = container_of(nhc, struct fib_nh, nh_common);
1601 rt->dst.tclassid = nh->nh_tclassid;
1602 }
1603#endif
1604 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1605 if (unlikely(fnhe))
1606 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1607 else if (do_cache)
1608 cached = rt_cache_route(nhc, rt);
1609 if (unlikely(!cached)) {
1610 /* Routes we intend to cache in nexthop exception or
1611 * FIB nexthop have the DST_NOCACHE bit clear.
1612 * However, if we are unsuccessful at storing this
1613 * route into the cache we really need to set it.
1614 */
1615 if (!rt->rt_gw4) {
1616 rt->rt_gw_family = AF_INET;
1617 rt->rt_gw4 = daddr;
1618 }
1619 rt_add_uncached_list(rt);
1620 }
1621 } else
1622 rt_add_uncached_list(rt);
1623
1624#ifdef CONFIG_IP_ROUTE_CLASSID
1625#ifdef CONFIG_IP_MULTIPLE_TABLES
1626 set_class_tag(rt, res->tclassid);
1627#endif
1628 set_class_tag(rt, itag);
1629#endif
1630}
1631
1632struct rtable *rt_dst_alloc(struct net_device *dev,
1633 unsigned int flags, u16 type,
1634 bool noxfrm)
1635{
1636 struct rtable *rt;
1637
1638 rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1639 (noxfrm ? DST_NOXFRM : 0));
1640
1641 if (rt) {
1642 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1643 rt->rt_flags = flags;
1644 rt->rt_type = type;
1645 rt->rt_is_input = 0;
1646 rt->rt_iif = 0;
1647 rt->rt_pmtu = 0;
1648 rt->rt_mtu_locked = 0;
1649 rt->rt_uses_gateway = 0;
1650 rt->rt_gw_family = 0;
1651 rt->rt_gw4 = 0;
1652
1653 rt->dst.output = ip_output;
1654 if (flags & RTCF_LOCAL)
1655 rt->dst.input = ip_local_deliver;
1656 }
1657
1658 return rt;
1659}
1660EXPORT_SYMBOL(rt_dst_alloc);
1661
1662struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1663{
1664 struct rtable *new_rt;
1665
1666 new_rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1667 rt->dst.flags);
1668
1669 if (new_rt) {
1670 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1671 new_rt->rt_flags = rt->rt_flags;
1672 new_rt->rt_type = rt->rt_type;
1673 new_rt->rt_is_input = rt->rt_is_input;
1674 new_rt->rt_iif = rt->rt_iif;
1675 new_rt->rt_pmtu = rt->rt_pmtu;
1676 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1677 new_rt->rt_gw_family = rt->rt_gw_family;
1678 if (rt->rt_gw_family == AF_INET)
1679 new_rt->rt_gw4 = rt->rt_gw4;
1680 else if (rt->rt_gw_family == AF_INET6)
1681 new_rt->rt_gw6 = rt->rt_gw6;
1682
1683 new_rt->dst.input = rt->dst.input;
1684 new_rt->dst.output = rt->dst.output;
1685 new_rt->dst.error = rt->dst.error;
1686 new_rt->dst.lastuse = jiffies;
1687 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1688 }
1689 return new_rt;
1690}
1691EXPORT_SYMBOL(rt_dst_clone);
1692
1693/* called in rcu_read_lock() section */
1694enum skb_drop_reason
1695ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1696 dscp_t dscp, struct net_device *dev,
1697 struct in_device *in_dev, u32 *itag)
1698{
1699 enum skb_drop_reason reason;
1700
1701 /* Primary sanity checks. */
1702 if (!in_dev)
1703 return SKB_DROP_REASON_NOT_SPECIFIED;
1704
1705 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1706 return SKB_DROP_REASON_IP_INVALID_SOURCE;
1707
1708 if (skb->protocol != htons(ETH_P_IP))
1709 return SKB_DROP_REASON_INVALID_PROTO;
1710
1711 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1712 return SKB_DROP_REASON_IP_LOCALNET;
1713
1714 if (ipv4_is_zeronet(saddr)) {
1715 if (!ipv4_is_local_multicast(daddr) &&
1716 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1717 return SKB_DROP_REASON_IP_INVALID_SOURCE;
1718 } else {
1719 reason = fib_validate_source_reason(skb, saddr, 0, dscp, 0,
1720 dev, in_dev, itag);
1721 if (reason)
1722 return reason;
1723 }
1724 return SKB_NOT_DROPPED_YET;
1725}
1726
1727/* called in rcu_read_lock() section */
1728static enum skb_drop_reason
1729ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1730 dscp_t dscp, struct net_device *dev, int our)
1731{
1732 struct in_device *in_dev = __in_dev_get_rcu(dev);
1733 unsigned int flags = RTCF_MULTICAST;
1734 enum skb_drop_reason reason;
1735 struct rtable *rth;
1736 u32 itag = 0;
1737
1738 reason = ip_mc_validate_source(skb, daddr, saddr, dscp, dev, in_dev,
1739 &itag);
1740 if (reason)
1741 return reason;
1742
1743 if (our)
1744 flags |= RTCF_LOCAL;
1745
1746 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1747 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1748
1749 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1750 false);
1751 if (!rth)
1752 return SKB_DROP_REASON_NOMEM;
1753
1754#ifdef CONFIG_IP_ROUTE_CLASSID
1755 rth->dst.tclassid = itag;
1756#endif
1757 rth->dst.output = ip_rt_bug;
1758 rth->rt_is_input= 1;
1759
1760#ifdef CONFIG_IP_MROUTE
1761 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1762 rth->dst.input = ip_mr_input;
1763#endif
1764 RT_CACHE_STAT_INC(in_slow_mc);
1765
1766 skb_dst_drop(skb);
1767 skb_dst_set(skb, &rth->dst);
1768 return SKB_NOT_DROPPED_YET;
1769}
1770
1771
1772static void ip_handle_martian_source(struct net_device *dev,
1773 struct in_device *in_dev,
1774 struct sk_buff *skb,
1775 __be32 daddr,
1776 __be32 saddr)
1777{
1778 RT_CACHE_STAT_INC(in_martian_src);
1779#ifdef CONFIG_IP_ROUTE_VERBOSE
1780 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1781 /*
1782 * RFC1812 recommendation, if source is martian,
1783 * the only hint is MAC header.
1784 */
1785 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1786 &daddr, &saddr, dev->name);
1787 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1788 print_hex_dump(KERN_WARNING, "ll header: ",
1789 DUMP_PREFIX_OFFSET, 16, 1,
1790 skb_mac_header(skb),
1791 dev->hard_header_len, false);
1792 }
1793 }
1794#endif
1795}
1796
1797/* called in rcu_read_lock() section */
1798static enum skb_drop_reason
1799__mkroute_input(struct sk_buff *skb, const struct fib_result *res,
1800 struct in_device *in_dev, __be32 daddr,
1801 __be32 saddr, dscp_t dscp)
1802{
1803 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
1804 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1805 struct net_device *dev = nhc->nhc_dev;
1806 struct fib_nh_exception *fnhe;
1807 struct rtable *rth;
1808 int err;
1809 struct in_device *out_dev;
1810 bool do_cache;
1811 u32 itag = 0;
1812
1813 /* get a working reference to the output device */
1814 out_dev = __in_dev_get_rcu(dev);
1815 if (!out_dev) {
1816 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1817 return reason;
1818 }
1819
1820 err = fib_validate_source(skb, saddr, daddr, dscp, FIB_RES_OIF(*res),
1821 in_dev->dev, in_dev, &itag);
1822 if (err < 0) {
1823 reason = -err;
1824 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1825 saddr);
1826
1827 goto cleanup;
1828 }
1829
1830 do_cache = res->fi && !itag;
1831 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1832 skb->protocol == htons(ETH_P_IP)) {
1833 __be32 gw;
1834
1835 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1836 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1837 inet_addr_onlink(out_dev, saddr, gw))
1838 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1839 }
1840
1841 if (skb->protocol != htons(ETH_P_IP)) {
1842 /* Not IP (i.e. ARP). Do not create route, if it is
1843 * invalid for proxy arp. DNAT routes are always valid.
1844 *
1845 * Proxy arp feature have been extended to allow, ARP
1846 * replies back to the same interface, to support
1847 * Private VLAN switch technologies. See arp.c.
1848 */
1849 if (out_dev == in_dev &&
1850 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1851 reason = SKB_DROP_REASON_ARP_PVLAN_DISABLE;
1852 goto cleanup;
1853 }
1854 }
1855
1856 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1857 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1858
1859 fnhe = find_exception(nhc, daddr);
1860 if (do_cache) {
1861 if (fnhe)
1862 rth = rcu_dereference(fnhe->fnhe_rth_input);
1863 else
1864 rth = rcu_dereference(nhc->nhc_rth_input);
1865 if (rt_cache_valid(rth)) {
1866 skb_dst_set_noref(skb, &rth->dst);
1867 goto out;
1868 }
1869 }
1870
1871 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1872 IN_DEV_ORCONF(out_dev, NOXFRM));
1873 if (!rth) {
1874 reason = SKB_DROP_REASON_NOMEM;
1875 goto cleanup;
1876 }
1877
1878 rth->rt_is_input = 1;
1879 RT_CACHE_STAT_INC(in_slow_tot);
1880
1881 rth->dst.input = ip_forward;
1882
1883 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1884 do_cache);
1885 lwtunnel_set_redirect(&rth->dst);
1886 skb_dst_set(skb, &rth->dst);
1887out:
1888 reason = SKB_NOT_DROPPED_YET;
1889cleanup:
1890 return reason;
1891}
1892
1893#ifdef CONFIG_IP_ROUTE_MULTIPATH
1894/* To make ICMP packets follow the right flow, the multipath hash is
1895 * calculated from the inner IP addresses.
1896 */
1897static void ip_multipath_l3_keys(const struct sk_buff *skb,
1898 struct flow_keys *hash_keys)
1899{
1900 const struct iphdr *outer_iph = ip_hdr(skb);
1901 const struct iphdr *key_iph = outer_iph;
1902 const struct iphdr *inner_iph;
1903 const struct icmphdr *icmph;
1904 struct iphdr _inner_iph;
1905 struct icmphdr _icmph;
1906
1907 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1908 goto out;
1909
1910 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1911 goto out;
1912
1913 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1914 &_icmph);
1915 if (!icmph)
1916 goto out;
1917
1918 if (!icmp_is_err(icmph->type))
1919 goto out;
1920
1921 inner_iph = skb_header_pointer(skb,
1922 outer_iph->ihl * 4 + sizeof(_icmph),
1923 sizeof(_inner_iph), &_inner_iph);
1924 if (!inner_iph)
1925 goto out;
1926
1927 key_iph = inner_iph;
1928out:
1929 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1930 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1931}
1932
1933static u32 fib_multipath_custom_hash_outer(const struct net *net,
1934 const struct sk_buff *skb,
1935 bool *p_has_inner)
1936{
1937 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1938 struct flow_keys keys, hash_keys;
1939
1940 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1941 return 0;
1942
1943 memset(&hash_keys, 0, sizeof(hash_keys));
1944 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1945
1946 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1947 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1948 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1949 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1950 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1951 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1952 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1953 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1954 hash_keys.ports.src = keys.ports.src;
1955 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1956 hash_keys.ports.dst = keys.ports.dst;
1957
1958 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1959 return fib_multipath_hash_from_keys(net, &hash_keys);
1960}
1961
1962static u32 fib_multipath_custom_hash_inner(const struct net *net,
1963 const struct sk_buff *skb,
1964 bool has_inner)
1965{
1966 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1967 struct flow_keys keys, hash_keys;
1968
1969 /* We assume the packet carries an encapsulation, but if none was
1970 * encountered during dissection of the outer flow, then there is no
1971 * point in calling the flow dissector again.
1972 */
1973 if (!has_inner)
1974 return 0;
1975
1976 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1977 return 0;
1978
1979 memset(&hash_keys, 0, sizeof(hash_keys));
1980 skb_flow_dissect_flow_keys(skb, &keys, 0);
1981
1982 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1983 return 0;
1984
1985 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1986 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1987 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1988 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1989 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1990 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1991 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1992 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1993 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1994 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1995 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1996 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1997 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1998 hash_keys.tags.flow_label = keys.tags.flow_label;
1999 }
2000
2001 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
2002 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2003 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
2004 hash_keys.ports.src = keys.ports.src;
2005 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
2006 hash_keys.ports.dst = keys.ports.dst;
2007
2008 return fib_multipath_hash_from_keys(net, &hash_keys);
2009}
2010
2011static u32 fib_multipath_custom_hash_skb(const struct net *net,
2012 const struct sk_buff *skb)
2013{
2014 u32 mhash, mhash_inner;
2015 bool has_inner = true;
2016
2017 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
2018 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
2019
2020 return jhash_2words(mhash, mhash_inner, 0);
2021}
2022
2023static u32 fib_multipath_custom_hash_fl4(const struct net *net,
2024 const struct flowi4 *fl4)
2025{
2026 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
2027 struct flow_keys hash_keys;
2028
2029 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
2030 return 0;
2031
2032 memset(&hash_keys, 0, sizeof(hash_keys));
2033 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2034 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2035 hash_keys.addrs.v4addrs.src = fl4->saddr;
2036 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2037 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2038 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2039 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2040 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2041 hash_keys.ports.src = fl4->fl4_sport;
2042 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2043 hash_keys.ports.dst = fl4->fl4_dport;
2044
2045 return fib_multipath_hash_from_keys(net, &hash_keys);
2046}
2047
2048/* if skb is set it will be used and fl4 can be NULL */
2049int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2050 const struct sk_buff *skb, struct flow_keys *flkeys)
2051{
2052 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2053 struct flow_keys hash_keys;
2054 u32 mhash = 0;
2055
2056 switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
2057 case 0:
2058 memset(&hash_keys, 0, sizeof(hash_keys));
2059 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2060 if (skb) {
2061 ip_multipath_l3_keys(skb, &hash_keys);
2062 } else {
2063 hash_keys.addrs.v4addrs.src = fl4->saddr;
2064 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2065 }
2066 mhash = fib_multipath_hash_from_keys(net, &hash_keys);
2067 break;
2068 case 1:
2069 /* skb is currently provided only when forwarding */
2070 if (skb) {
2071 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2072 struct flow_keys keys;
2073
2074 /* short-circuit if we already have L4 hash present */
2075 if (skb->l4_hash)
2076 return skb_get_hash_raw(skb) >> 1;
2077
2078 memset(&hash_keys, 0, sizeof(hash_keys));
2079
2080 if (!flkeys) {
2081 skb_flow_dissect_flow_keys(skb, &keys, flag);
2082 flkeys = &keys;
2083 }
2084
2085 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2086 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2087 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2088 hash_keys.ports.src = flkeys->ports.src;
2089 hash_keys.ports.dst = flkeys->ports.dst;
2090 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2091 } else {
2092 memset(&hash_keys, 0, sizeof(hash_keys));
2093 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2094 hash_keys.addrs.v4addrs.src = fl4->saddr;
2095 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2096 hash_keys.ports.src = fl4->fl4_sport;
2097 hash_keys.ports.dst = fl4->fl4_dport;
2098 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2099 }
2100 mhash = fib_multipath_hash_from_keys(net, &hash_keys);
2101 break;
2102 case 2:
2103 memset(&hash_keys, 0, sizeof(hash_keys));
2104 /* skb is currently provided only when forwarding */
2105 if (skb) {
2106 struct flow_keys keys;
2107
2108 skb_flow_dissect_flow_keys(skb, &keys, 0);
2109 /* Inner can be v4 or v6 */
2110 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2111 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2112 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2113 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2114 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2115 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2116 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2117 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2118 hash_keys.tags.flow_label = keys.tags.flow_label;
2119 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2120 } else {
2121 /* Same as case 0 */
2122 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2123 ip_multipath_l3_keys(skb, &hash_keys);
2124 }
2125 } else {
2126 /* Same as case 0 */
2127 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2128 hash_keys.addrs.v4addrs.src = fl4->saddr;
2129 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2130 }
2131 mhash = fib_multipath_hash_from_keys(net, &hash_keys);
2132 break;
2133 case 3:
2134 if (skb)
2135 mhash = fib_multipath_custom_hash_skb(net, skb);
2136 else
2137 mhash = fib_multipath_custom_hash_fl4(net, fl4);
2138 break;
2139 }
2140
2141 if (multipath_hash)
2142 mhash = jhash_2words(mhash, multipath_hash, 0);
2143
2144 return mhash >> 1;
2145}
2146#endif /* CONFIG_IP_ROUTE_MULTIPATH */
2147
2148static enum skb_drop_reason
2149ip_mkroute_input(struct sk_buff *skb, struct fib_result *res,
2150 struct in_device *in_dev, __be32 daddr,
2151 __be32 saddr, dscp_t dscp, struct flow_keys *hkeys)
2152{
2153#ifdef CONFIG_IP_ROUTE_MULTIPATH
2154 if (res->fi && fib_info_num_path(res->fi) > 1) {
2155 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2156
2157 fib_select_multipath(res, h);
2158 IPCB(skb)->flags |= IPSKB_MULTIPATH;
2159 }
2160#endif
2161
2162 /* create a routing cache entry */
2163 return __mkroute_input(skb, res, in_dev, daddr, saddr, dscp);
2164}
2165
2166/* Implements all the saddr-related checks as ip_route_input_slow(),
2167 * assuming daddr is valid and the destination is not a local broadcast one.
2168 * Uses the provided hint instead of performing a route lookup.
2169 */
2170enum skb_drop_reason
2171ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2172 dscp_t dscp, struct net_device *dev,
2173 const struct sk_buff *hint)
2174{
2175 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
2176 struct in_device *in_dev = __in_dev_get_rcu(dev);
2177 struct rtable *rt = skb_rtable(hint);
2178 struct net *net = dev_net(dev);
2179 u32 tag = 0;
2180
2181 if (!in_dev)
2182 return reason;
2183
2184 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) {
2185 reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2186 goto martian_source;
2187 }
2188
2189 if (ipv4_is_zeronet(saddr)) {
2190 reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2191 goto martian_source;
2192 }
2193
2194 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
2195 reason = SKB_DROP_REASON_IP_LOCALNET;
2196 goto martian_source;
2197 }
2198
2199 if (rt->rt_type != RTN_LOCAL)
2200 goto skip_validate_source;
2201
2202 reason = fib_validate_source_reason(skb, saddr, daddr, dscp, 0, dev,
2203 in_dev, &tag);
2204 if (reason)
2205 goto martian_source;
2206
2207skip_validate_source:
2208 skb_dst_copy(skb, hint);
2209 return SKB_NOT_DROPPED_YET;
2210
2211martian_source:
2212 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2213 return reason;
2214}
2215
2216/* get device for dst_alloc with local routes */
2217static struct net_device *ip_rt_get_dev(struct net *net,
2218 const struct fib_result *res)
2219{
2220 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2221 struct net_device *dev = NULL;
2222
2223 if (nhc)
2224 dev = l3mdev_master_dev_rcu(nhc->nhc_dev);
2225
2226 return dev ? : net->loopback_dev;
2227}
2228
2229/*
2230 * NOTE. We drop all the packets that has local source
2231 * addresses, because every properly looped back packet
2232 * must have correct destination already attached by output routine.
2233 * Changes in the enforced policies must be applied also to
2234 * ip_route_use_hint().
2235 *
2236 * Such approach solves two big problems:
2237 * 1. Not simplex devices are handled properly.
2238 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2239 * called with rcu_read_lock()
2240 */
2241
2242static enum skb_drop_reason
2243ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2244 dscp_t dscp, struct net_device *dev,
2245 struct fib_result *res)
2246{
2247 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
2248 struct in_device *in_dev = __in_dev_get_rcu(dev);
2249 struct flow_keys *flkeys = NULL, _flkeys;
2250 struct net *net = dev_net(dev);
2251 struct ip_tunnel_info *tun_info;
2252 int err = -EINVAL;
2253 unsigned int flags = 0;
2254 u32 itag = 0;
2255 struct rtable *rth;
2256 struct flowi4 fl4;
2257 bool do_cache = true;
2258
2259 /* IP on this device is disabled. */
2260
2261 if (!in_dev)
2262 goto out;
2263
2264 /* Check for the most weird martians, which can be not detected
2265 * by fib_lookup.
2266 */
2267
2268 tun_info = skb_tunnel_info(skb);
2269 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2270 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2271 else
2272 fl4.flowi4_tun_key.tun_id = 0;
2273 skb_dst_drop(skb);
2274
2275 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) {
2276 reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2277 goto martian_source;
2278 }
2279
2280 res->fi = NULL;
2281 res->table = NULL;
2282 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2283 goto brd_input;
2284
2285 /* Accept zero addresses only to limited broadcast;
2286 * I even do not know to fix it or not. Waiting for complains :-)
2287 */
2288 if (ipv4_is_zeronet(saddr)) {
2289 reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2290 goto martian_source;
2291 }
2292
2293 if (ipv4_is_zeronet(daddr)) {
2294 reason = SKB_DROP_REASON_IP_INVALID_DEST;
2295 goto martian_destination;
2296 }
2297
2298 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2299 * and call it once if daddr or/and saddr are loopback addresses
2300 */
2301 if (ipv4_is_loopback(daddr)) {
2302 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
2303 reason = SKB_DROP_REASON_IP_LOCALNET;
2304 goto martian_destination;
2305 }
2306 } else if (ipv4_is_loopback(saddr)) {
2307 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
2308 reason = SKB_DROP_REASON_IP_LOCALNET;
2309 goto martian_source;
2310 }
2311 }
2312
2313 /*
2314 * Now we are ready to route packet.
2315 */
2316 fl4.flowi4_l3mdev = 0;
2317 fl4.flowi4_oif = 0;
2318 fl4.flowi4_iif = dev->ifindex;
2319 fl4.flowi4_mark = skb->mark;
2320 fl4.flowi4_tos = inet_dscp_to_dsfield(dscp);
2321 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2322 fl4.flowi4_flags = 0;
2323 fl4.daddr = daddr;
2324 fl4.saddr = saddr;
2325 fl4.flowi4_uid = sock_net_uid(net, NULL);
2326 fl4.flowi4_multipath_hash = 0;
2327
2328 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2329 flkeys = &_flkeys;
2330 } else {
2331 fl4.flowi4_proto = 0;
2332 fl4.fl4_sport = 0;
2333 fl4.fl4_dport = 0;
2334 }
2335
2336 err = fib_lookup(net, &fl4, res, 0);
2337 if (err != 0) {
2338 if (!IN_DEV_FORWARD(in_dev))
2339 err = -EHOSTUNREACH;
2340 goto no_route;
2341 }
2342
2343 if (res->type == RTN_BROADCAST) {
2344 if (IN_DEV_BFORWARD(in_dev))
2345 goto make_route;
2346 /* not do cache if bc_forwarding is enabled */
2347 if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING))
2348 do_cache = false;
2349 goto brd_input;
2350 }
2351
2352 err = -EINVAL;
2353 if (res->type == RTN_LOCAL) {
2354 reason = fib_validate_source_reason(skb, saddr, daddr, dscp,
2355 0, dev, in_dev, &itag);
2356 if (reason)
2357 goto martian_source;
2358 goto local_input;
2359 }
2360
2361 if (!IN_DEV_FORWARD(in_dev)) {
2362 err = -EHOSTUNREACH;
2363 goto no_route;
2364 }
2365 if (res->type != RTN_UNICAST) {
2366 reason = SKB_DROP_REASON_IP_INVALID_DEST;
2367 goto martian_destination;
2368 }
2369
2370make_route:
2371 reason = ip_mkroute_input(skb, res, in_dev, daddr, saddr, dscp,
2372 flkeys);
2373
2374out:
2375 return reason;
2376
2377brd_input:
2378 if (skb->protocol != htons(ETH_P_IP)) {
2379 reason = SKB_DROP_REASON_INVALID_PROTO;
2380 goto out;
2381 }
2382
2383 if (!ipv4_is_zeronet(saddr)) {
2384 reason = fib_validate_source_reason(skb, saddr, 0, dscp, 0,
2385 dev, in_dev, &itag);
2386 if (reason)
2387 goto martian_source;
2388 }
2389 flags |= RTCF_BROADCAST;
2390 res->type = RTN_BROADCAST;
2391 RT_CACHE_STAT_INC(in_brd);
2392
2393local_input:
2394 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
2395 IPCB(skb)->flags |= IPSKB_NOPOLICY;
2396
2397 do_cache &= res->fi && !itag;
2398 if (do_cache) {
2399 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2400
2401 rth = rcu_dereference(nhc->nhc_rth_input);
2402 if (rt_cache_valid(rth)) {
2403 skb_dst_set_noref(skb, &rth->dst);
2404 reason = SKB_NOT_DROPPED_YET;
2405 goto out;
2406 }
2407 }
2408
2409 rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2410 flags | RTCF_LOCAL, res->type, false);
2411 if (!rth)
2412 goto e_nobufs;
2413
2414 rth->dst.output= ip_rt_bug;
2415#ifdef CONFIG_IP_ROUTE_CLASSID
2416 rth->dst.tclassid = itag;
2417#endif
2418 rth->rt_is_input = 1;
2419
2420 RT_CACHE_STAT_INC(in_slow_tot);
2421 if (res->type == RTN_UNREACHABLE) {
2422 rth->dst.input= ip_error;
2423 rth->dst.error= -err;
2424 rth->rt_flags &= ~RTCF_LOCAL;
2425 }
2426
2427 if (do_cache) {
2428 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2429
2430 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2431 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2432 WARN_ON(rth->dst.input == lwtunnel_input);
2433 rth->dst.lwtstate->orig_input = rth->dst.input;
2434 rth->dst.input = lwtunnel_input;
2435 }
2436
2437 if (unlikely(!rt_cache_route(nhc, rth)))
2438 rt_add_uncached_list(rth);
2439 }
2440 skb_dst_set(skb, &rth->dst);
2441 reason = SKB_NOT_DROPPED_YET;
2442 goto out;
2443
2444no_route:
2445 RT_CACHE_STAT_INC(in_no_route);
2446 res->type = RTN_UNREACHABLE;
2447 res->fi = NULL;
2448 res->table = NULL;
2449 goto local_input;
2450
2451 /*
2452 * Do not cache martian addresses: they should be logged (RFC1812)
2453 */
2454martian_destination:
2455 RT_CACHE_STAT_INC(in_martian_dst);
2456#ifdef CONFIG_IP_ROUTE_VERBOSE
2457 if (IN_DEV_LOG_MARTIANS(in_dev))
2458 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2459 &daddr, &saddr, dev->name);
2460#endif
2461 goto out;
2462
2463e_nobufs:
2464 reason = SKB_DROP_REASON_NOMEM;
2465 goto out;
2466
2467martian_source:
2468 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2469 goto out;
2470}
2471
2472/* called with rcu_read_lock held */
2473static enum skb_drop_reason
2474ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2475 dscp_t dscp, struct net_device *dev,
2476 struct fib_result *res)
2477{
2478 /* Multicast recognition logic is moved from route cache to here.
2479 * The problem was that too many Ethernet cards have broken/missing
2480 * hardware multicast filters :-( As result the host on multicasting
2481 * network acquires a lot of useless route cache entries, sort of
2482 * SDR messages from all the world. Now we try to get rid of them.
2483 * Really, provided software IP multicast filter is organized
2484 * reasonably (at least, hashed), it does not result in a slowdown
2485 * comparing with route cache reject entries.
2486 * Note, that multicast routers are not affected, because
2487 * route cache entry is created eventually.
2488 */
2489 if (ipv4_is_multicast(daddr)) {
2490 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
2491 struct in_device *in_dev = __in_dev_get_rcu(dev);
2492 int our = 0;
2493
2494 if (!in_dev)
2495 return reason;
2496
2497 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2498 ip_hdr(skb)->protocol);
2499
2500 /* check l3 master if no match yet */
2501 if (!our && netif_is_l3_slave(dev)) {
2502 struct in_device *l3_in_dev;
2503
2504 l3_in_dev = __in_dev_get_rcu(skb->dev);
2505 if (l3_in_dev)
2506 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2507 ip_hdr(skb)->protocol);
2508 }
2509
2510 if (our
2511#ifdef CONFIG_IP_MROUTE
2512 ||
2513 (!ipv4_is_local_multicast(daddr) &&
2514 IN_DEV_MFORWARD(in_dev))
2515#endif
2516 ) {
2517 reason = ip_route_input_mc(skb, daddr, saddr, dscp,
2518 dev, our);
2519 }
2520 return reason;
2521 }
2522
2523 return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res);
2524}
2525
2526enum skb_drop_reason ip_route_input_noref(struct sk_buff *skb, __be32 daddr,
2527 __be32 saddr, dscp_t dscp,
2528 struct net_device *dev)
2529{
2530 enum skb_drop_reason reason;
2531 struct fib_result res;
2532
2533 rcu_read_lock();
2534 reason = ip_route_input_rcu(skb, daddr, saddr, dscp, dev, &res);
2535 rcu_read_unlock();
2536
2537 return reason;
2538}
2539EXPORT_SYMBOL(ip_route_input_noref);
2540
2541/* called with rcu_read_lock() */
2542static struct rtable *__mkroute_output(const struct fib_result *res,
2543 const struct flowi4 *fl4, int orig_oif,
2544 struct net_device *dev_out,
2545 unsigned int flags)
2546{
2547 struct fib_info *fi = res->fi;
2548 struct fib_nh_exception *fnhe;
2549 struct in_device *in_dev;
2550 u16 type = res->type;
2551 struct rtable *rth;
2552 bool do_cache;
2553
2554 in_dev = __in_dev_get_rcu(dev_out);
2555 if (!in_dev)
2556 return ERR_PTR(-EINVAL);
2557
2558 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2559 if (ipv4_is_loopback(fl4->saddr) &&
2560 !(dev_out->flags & IFF_LOOPBACK) &&
2561 !netif_is_l3_master(dev_out))
2562 return ERR_PTR(-EINVAL);
2563
2564 if (ipv4_is_lbcast(fl4->daddr))
2565 type = RTN_BROADCAST;
2566 else if (ipv4_is_multicast(fl4->daddr))
2567 type = RTN_MULTICAST;
2568 else if (ipv4_is_zeronet(fl4->daddr))
2569 return ERR_PTR(-EINVAL);
2570
2571 if (dev_out->flags & IFF_LOOPBACK)
2572 flags |= RTCF_LOCAL;
2573
2574 do_cache = true;
2575 if (type == RTN_BROADCAST) {
2576 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2577 fi = NULL;
2578 } else if (type == RTN_MULTICAST) {
2579 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2580 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2581 fl4->flowi4_proto))
2582 flags &= ~RTCF_LOCAL;
2583 else
2584 do_cache = false;
2585 /* If multicast route do not exist use
2586 * default one, but do not gateway in this case.
2587 * Yes, it is hack.
2588 */
2589 if (fi && res->prefixlen < 4)
2590 fi = NULL;
2591 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2592 (orig_oif != dev_out->ifindex)) {
2593 /* For local routes that require a particular output interface
2594 * we do not want to cache the result. Caching the result
2595 * causes incorrect behaviour when there are multiple source
2596 * addresses on the interface, the end result being that if the
2597 * intended recipient is waiting on that interface for the
2598 * packet he won't receive it because it will be delivered on
2599 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2600 * be set to the loopback interface as well.
2601 */
2602 do_cache = false;
2603 }
2604
2605 fnhe = NULL;
2606 do_cache &= fi != NULL;
2607 if (fi) {
2608 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2609 struct rtable __rcu **prth;
2610
2611 fnhe = find_exception(nhc, fl4->daddr);
2612 if (!do_cache)
2613 goto add;
2614 if (fnhe) {
2615 prth = &fnhe->fnhe_rth_output;
2616 } else {
2617 if (unlikely(fl4->flowi4_flags &
2618 FLOWI_FLAG_KNOWN_NH &&
2619 !(nhc->nhc_gw_family &&
2620 nhc->nhc_scope == RT_SCOPE_LINK))) {
2621 do_cache = false;
2622 goto add;
2623 }
2624 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2625 }
2626 rth = rcu_dereference(*prth);
2627 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2628 return rth;
2629 }
2630
2631add:
2632 rth = rt_dst_alloc(dev_out, flags, type,
2633 IN_DEV_ORCONF(in_dev, NOXFRM));
2634 if (!rth)
2635 return ERR_PTR(-ENOBUFS);
2636
2637 rth->rt_iif = orig_oif;
2638
2639 RT_CACHE_STAT_INC(out_slow_tot);
2640
2641 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2642 if (flags & RTCF_LOCAL &&
2643 !(dev_out->flags & IFF_LOOPBACK)) {
2644 rth->dst.output = ip_mc_output;
2645 RT_CACHE_STAT_INC(out_slow_mc);
2646 }
2647#ifdef CONFIG_IP_MROUTE
2648 if (type == RTN_MULTICAST) {
2649 if (IN_DEV_MFORWARD(in_dev) &&
2650 !ipv4_is_local_multicast(fl4->daddr)) {
2651 rth->dst.input = ip_mr_input;
2652 rth->dst.output = ip_mc_output;
2653 }
2654 }
2655#endif
2656 }
2657
2658 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2659 lwtunnel_set_redirect(&rth->dst);
2660
2661 return rth;
2662}
2663
2664/*
2665 * Major route resolver routine.
2666 */
2667
2668struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2669 const struct sk_buff *skb)
2670{
2671 struct fib_result res = {
2672 .type = RTN_UNSPEC,
2673 .fi = NULL,
2674 .table = NULL,
2675 .tclassid = 0,
2676 };
2677 struct rtable *rth;
2678
2679 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2680 fl4->flowi4_tos &= INET_DSCP_MASK;
2681
2682 rcu_read_lock();
2683 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2684 rcu_read_unlock();
2685
2686 return rth;
2687}
2688EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2689
2690struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2691 struct fib_result *res,
2692 const struct sk_buff *skb)
2693{
2694 struct net_device *dev_out = NULL;
2695 int orig_oif = fl4->flowi4_oif;
2696 unsigned int flags = 0;
2697 struct rtable *rth;
2698 int err;
2699
2700 if (fl4->saddr) {
2701 if (ipv4_is_multicast(fl4->saddr) ||
2702 ipv4_is_lbcast(fl4->saddr) ||
2703 ipv4_is_zeronet(fl4->saddr)) {
2704 rth = ERR_PTR(-EINVAL);
2705 goto out;
2706 }
2707
2708 rth = ERR_PTR(-ENETUNREACH);
2709
2710 /* I removed check for oif == dev_out->oif here.
2711 * It was wrong for two reasons:
2712 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2713 * is assigned to multiple interfaces.
2714 * 2. Moreover, we are allowed to send packets with saddr
2715 * of another iface. --ANK
2716 */
2717
2718 if (fl4->flowi4_oif == 0 &&
2719 (ipv4_is_multicast(fl4->daddr) ||
2720 ipv4_is_lbcast(fl4->daddr))) {
2721 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2722 dev_out = __ip_dev_find(net, fl4->saddr, false);
2723 if (!dev_out)
2724 goto out;
2725
2726 /* Special hack: user can direct multicasts
2727 * and limited broadcast via necessary interface
2728 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2729 * This hack is not just for fun, it allows
2730 * vic,vat and friends to work.
2731 * They bind socket to loopback, set ttl to zero
2732 * and expect that it will work.
2733 * From the viewpoint of routing cache they are broken,
2734 * because we are not allowed to build multicast path
2735 * with loopback source addr (look, routing cache
2736 * cannot know, that ttl is zero, so that packet
2737 * will not leave this host and route is valid).
2738 * Luckily, this hack is good workaround.
2739 */
2740
2741 fl4->flowi4_oif = dev_out->ifindex;
2742 goto make_route;
2743 }
2744
2745 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2746 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2747 if (!__ip_dev_find(net, fl4->saddr, false))
2748 goto out;
2749 }
2750 }
2751
2752
2753 if (fl4->flowi4_oif) {
2754 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2755 rth = ERR_PTR(-ENODEV);
2756 if (!dev_out)
2757 goto out;
2758
2759 /* RACE: Check return value of inet_select_addr instead. */
2760 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2761 rth = ERR_PTR(-ENETUNREACH);
2762 goto out;
2763 }
2764 if (ipv4_is_local_multicast(fl4->daddr) ||
2765 ipv4_is_lbcast(fl4->daddr) ||
2766 fl4->flowi4_proto == IPPROTO_IGMP) {
2767 if (!fl4->saddr)
2768 fl4->saddr = inet_select_addr(dev_out, 0,
2769 RT_SCOPE_LINK);
2770 goto make_route;
2771 }
2772 if (!fl4->saddr) {
2773 if (ipv4_is_multicast(fl4->daddr))
2774 fl4->saddr = inet_select_addr(dev_out, 0,
2775 fl4->flowi4_scope);
2776 else if (!fl4->daddr)
2777 fl4->saddr = inet_select_addr(dev_out, 0,
2778 RT_SCOPE_HOST);
2779 }
2780 }
2781
2782 if (!fl4->daddr) {
2783 fl4->daddr = fl4->saddr;
2784 if (!fl4->daddr)
2785 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2786 dev_out = net->loopback_dev;
2787 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2788 res->type = RTN_LOCAL;
2789 flags |= RTCF_LOCAL;
2790 goto make_route;
2791 }
2792
2793 err = fib_lookup(net, fl4, res, 0);
2794 if (err) {
2795 res->fi = NULL;
2796 res->table = NULL;
2797 if (fl4->flowi4_oif &&
2798 (ipv4_is_multicast(fl4->daddr) || !fl4->flowi4_l3mdev)) {
2799 /* Apparently, routing tables are wrong. Assume,
2800 * that the destination is on link.
2801 *
2802 * WHY? DW.
2803 * Because we are allowed to send to iface
2804 * even if it has NO routes and NO assigned
2805 * addresses. When oif is specified, routing
2806 * tables are looked up with only one purpose:
2807 * to catch if destination is gatewayed, rather than
2808 * direct. Moreover, if MSG_DONTROUTE is set,
2809 * we send packet, ignoring both routing tables
2810 * and ifaddr state. --ANK
2811 *
2812 *
2813 * We could make it even if oif is unknown,
2814 * likely IPv6, but we do not.
2815 */
2816
2817 if (fl4->saddr == 0)
2818 fl4->saddr = inet_select_addr(dev_out, 0,
2819 RT_SCOPE_LINK);
2820 res->type = RTN_UNICAST;
2821 goto make_route;
2822 }
2823 rth = ERR_PTR(err);
2824 goto out;
2825 }
2826
2827 if (res->type == RTN_LOCAL) {
2828 if (!fl4->saddr) {
2829 if (res->fi->fib_prefsrc)
2830 fl4->saddr = res->fi->fib_prefsrc;
2831 else
2832 fl4->saddr = fl4->daddr;
2833 }
2834
2835 /* L3 master device is the loopback for that domain */
2836 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2837 net->loopback_dev;
2838
2839 /* make sure orig_oif points to fib result device even
2840 * though packet rx/tx happens over loopback or l3mdev
2841 */
2842 orig_oif = FIB_RES_OIF(*res);
2843
2844 fl4->flowi4_oif = dev_out->ifindex;
2845 flags |= RTCF_LOCAL;
2846 goto make_route;
2847 }
2848
2849 fib_select_path(net, res, fl4, skb);
2850
2851 dev_out = FIB_RES_DEV(*res);
2852
2853make_route:
2854 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2855
2856out:
2857 return rth;
2858}
2859
2860static struct dst_ops ipv4_dst_blackhole_ops = {
2861 .family = AF_INET,
2862 .default_advmss = ipv4_default_advmss,
2863 .neigh_lookup = ipv4_neigh_lookup,
2864 .check = dst_blackhole_check,
2865 .cow_metrics = dst_blackhole_cow_metrics,
2866 .update_pmtu = dst_blackhole_update_pmtu,
2867 .redirect = dst_blackhole_redirect,
2868 .mtu = dst_blackhole_mtu,
2869};
2870
2871struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2872{
2873 struct rtable *ort = dst_rtable(dst_orig);
2874 struct rtable *rt;
2875
2876 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, 0);
2877 if (rt) {
2878 struct dst_entry *new = &rt->dst;
2879
2880 new->__use = 1;
2881 new->input = dst_discard;
2882 new->output = dst_discard_out;
2883
2884 new->dev = net->loopback_dev;
2885 netdev_hold(new->dev, &new->dev_tracker, GFP_ATOMIC);
2886
2887 rt->rt_is_input = ort->rt_is_input;
2888 rt->rt_iif = ort->rt_iif;
2889 rt->rt_pmtu = ort->rt_pmtu;
2890 rt->rt_mtu_locked = ort->rt_mtu_locked;
2891
2892 rt->rt_genid = rt_genid_ipv4(net);
2893 rt->rt_flags = ort->rt_flags;
2894 rt->rt_type = ort->rt_type;
2895 rt->rt_uses_gateway = ort->rt_uses_gateway;
2896 rt->rt_gw_family = ort->rt_gw_family;
2897 if (rt->rt_gw_family == AF_INET)
2898 rt->rt_gw4 = ort->rt_gw4;
2899 else if (rt->rt_gw_family == AF_INET6)
2900 rt->rt_gw6 = ort->rt_gw6;
2901 }
2902
2903 dst_release(dst_orig);
2904
2905 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2906}
2907
2908struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2909 const struct sock *sk)
2910{
2911 struct rtable *rt = __ip_route_output_key(net, flp4);
2912
2913 if (IS_ERR(rt))
2914 return rt;
2915
2916 if (flp4->flowi4_proto) {
2917 flp4->flowi4_oif = rt->dst.dev->ifindex;
2918 rt = dst_rtable(xfrm_lookup_route(net, &rt->dst,
2919 flowi4_to_flowi(flp4),
2920 sk, 0));
2921 }
2922
2923 return rt;
2924}
2925EXPORT_SYMBOL_GPL(ip_route_output_flow);
2926
2927/* called with rcu_read_lock held */
2928static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2929 struct rtable *rt, u32 table_id, dscp_t dscp,
2930 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2931 u32 seq, unsigned int flags)
2932{
2933 struct rtmsg *r;
2934 struct nlmsghdr *nlh;
2935 unsigned long expires = 0;
2936 u32 error;
2937 u32 metrics[RTAX_MAX];
2938
2939 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2940 if (!nlh)
2941 return -EMSGSIZE;
2942
2943 r = nlmsg_data(nlh);
2944 r->rtm_family = AF_INET;
2945 r->rtm_dst_len = 32;
2946 r->rtm_src_len = 0;
2947 r->rtm_tos = inet_dscp_to_dsfield(dscp);
2948 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2949 if (nla_put_u32(skb, RTA_TABLE, table_id))
2950 goto nla_put_failure;
2951 r->rtm_type = rt->rt_type;
2952 r->rtm_scope = RT_SCOPE_UNIVERSE;
2953 r->rtm_protocol = RTPROT_UNSPEC;
2954 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2955 if (rt->rt_flags & RTCF_NOTIFY)
2956 r->rtm_flags |= RTM_F_NOTIFY;
2957 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2958 r->rtm_flags |= RTCF_DOREDIRECT;
2959
2960 if (nla_put_in_addr(skb, RTA_DST, dst))
2961 goto nla_put_failure;
2962 if (src) {
2963 r->rtm_src_len = 32;
2964 if (nla_put_in_addr(skb, RTA_SRC, src))
2965 goto nla_put_failure;
2966 }
2967 if (rt->dst.dev &&
2968 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2969 goto nla_put_failure;
2970 if (rt->dst.lwtstate &&
2971 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
2972 goto nla_put_failure;
2973#ifdef CONFIG_IP_ROUTE_CLASSID
2974 if (rt->dst.tclassid &&
2975 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2976 goto nla_put_failure;
2977#endif
2978 if (fl4 && !rt_is_input_route(rt) &&
2979 fl4->saddr != src) {
2980 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2981 goto nla_put_failure;
2982 }
2983 if (rt->rt_uses_gateway) {
2984 if (rt->rt_gw_family == AF_INET &&
2985 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2986 goto nla_put_failure;
2987 } else if (rt->rt_gw_family == AF_INET6) {
2988 int alen = sizeof(struct in6_addr);
2989 struct nlattr *nla;
2990 struct rtvia *via;
2991
2992 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2993 if (!nla)
2994 goto nla_put_failure;
2995
2996 via = nla_data(nla);
2997 via->rtvia_family = AF_INET6;
2998 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2999 }
3000 }
3001
3002 expires = rt->dst.expires;
3003 if (expires) {
3004 unsigned long now = jiffies;
3005
3006 if (time_before(now, expires))
3007 expires -= now;
3008 else
3009 expires = 0;
3010 }
3011
3012 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
3013 if (rt->rt_pmtu && expires)
3014 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
3015 if (rt->rt_mtu_locked && expires)
3016 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
3017 if (rtnetlink_put_metrics(skb, metrics) < 0)
3018 goto nla_put_failure;
3019
3020 if (fl4) {
3021 if (fl4->flowi4_mark &&
3022 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
3023 goto nla_put_failure;
3024
3025 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
3026 nla_put_u32(skb, RTA_UID,
3027 from_kuid_munged(current_user_ns(),
3028 fl4->flowi4_uid)))
3029 goto nla_put_failure;
3030
3031 if (rt_is_input_route(rt)) {
3032#ifdef CONFIG_IP_MROUTE
3033 if (ipv4_is_multicast(dst) &&
3034 !ipv4_is_local_multicast(dst) &&
3035 IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) {
3036 int err = ipmr_get_route(net, skb,
3037 fl4->saddr, fl4->daddr,
3038 r, portid);
3039
3040 if (err <= 0) {
3041 if (err == 0)
3042 return 0;
3043 goto nla_put_failure;
3044 }
3045 } else
3046#endif
3047 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
3048 goto nla_put_failure;
3049 }
3050 }
3051
3052 error = rt->dst.error;
3053
3054 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
3055 goto nla_put_failure;
3056
3057 nlmsg_end(skb, nlh);
3058 return 0;
3059
3060nla_put_failure:
3061 nlmsg_cancel(skb, nlh);
3062 return -EMSGSIZE;
3063}
3064
3065static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3066 struct netlink_callback *cb, u32 table_id,
3067 struct fnhe_hash_bucket *bucket, int genid,
3068 int *fa_index, int fa_start, unsigned int flags)
3069{
3070 int i;
3071
3072 for (i = 0; i < FNHE_HASH_SIZE; i++) {
3073 struct fib_nh_exception *fnhe;
3074
3075 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3076 fnhe = rcu_dereference(fnhe->fnhe_next)) {
3077 struct rtable *rt;
3078 int err;
3079
3080 if (*fa_index < fa_start)
3081 goto next;
3082
3083 if (fnhe->fnhe_genid != genid)
3084 goto next;
3085
3086 if (fnhe->fnhe_expires &&
3087 time_after(jiffies, fnhe->fnhe_expires))
3088 goto next;
3089
3090 rt = rcu_dereference(fnhe->fnhe_rth_input);
3091 if (!rt)
3092 rt = rcu_dereference(fnhe->fnhe_rth_output);
3093 if (!rt)
3094 goto next;
3095
3096 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
3097 table_id, 0, NULL, skb,
3098 NETLINK_CB(cb->skb).portid,
3099 cb->nlh->nlmsg_seq, flags);
3100 if (err)
3101 return err;
3102next:
3103 (*fa_index)++;
3104 }
3105 }
3106
3107 return 0;
3108}
3109
3110int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3111 u32 table_id, struct fib_info *fi,
3112 int *fa_index, int fa_start, unsigned int flags)
3113{
3114 struct net *net = sock_net(cb->skb->sk);
3115 int nhsel, genid = fnhe_genid(net);
3116
3117 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3118 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3119 struct fnhe_hash_bucket *bucket;
3120 int err;
3121
3122 if (nhc->nhc_flags & RTNH_F_DEAD)
3123 continue;
3124
3125 rcu_read_lock();
3126 bucket = rcu_dereference(nhc->nhc_exceptions);
3127 err = 0;
3128 if (bucket)
3129 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3130 genid, fa_index, fa_start,
3131 flags);
3132 rcu_read_unlock();
3133 if (err)
3134 return err;
3135 }
3136
3137 return 0;
3138}
3139
3140static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3141 u8 ip_proto, __be16 sport,
3142 __be16 dport)
3143{
3144 struct sk_buff *skb;
3145 struct iphdr *iph;
3146
3147 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3148 if (!skb)
3149 return NULL;
3150
3151 /* Reserve room for dummy headers, this skb can pass
3152 * through good chunk of routing engine.
3153 */
3154 skb_reset_mac_header(skb);
3155 skb_reset_network_header(skb);
3156 skb->protocol = htons(ETH_P_IP);
3157 iph = skb_put(skb, sizeof(struct iphdr));
3158 iph->protocol = ip_proto;
3159 iph->saddr = src;
3160 iph->daddr = dst;
3161 iph->version = 0x4;
3162 iph->frag_off = 0;
3163 iph->ihl = 0x5;
3164 skb_set_transport_header(skb, skb->len);
3165
3166 switch (iph->protocol) {
3167 case IPPROTO_UDP: {
3168 struct udphdr *udph;
3169
3170 udph = skb_put_zero(skb, sizeof(struct udphdr));
3171 udph->source = sport;
3172 udph->dest = dport;
3173 udph->len = htons(sizeof(struct udphdr));
3174 udph->check = 0;
3175 break;
3176 }
3177 case IPPROTO_TCP: {
3178 struct tcphdr *tcph;
3179
3180 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3181 tcph->source = sport;
3182 tcph->dest = dport;
3183 tcph->doff = sizeof(struct tcphdr) / 4;
3184 tcph->rst = 1;
3185 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3186 src, dst, 0);
3187 break;
3188 }
3189 case IPPROTO_ICMP: {
3190 struct icmphdr *icmph;
3191
3192 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3193 icmph->type = ICMP_ECHO;
3194 icmph->code = 0;
3195 }
3196 }
3197
3198 return skb;
3199}
3200
3201static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3202 const struct nlmsghdr *nlh,
3203 struct nlattr **tb,
3204 struct netlink_ext_ack *extack)
3205{
3206 struct rtmsg *rtm;
3207 int i, err;
3208
3209 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3210 NL_SET_ERR_MSG(extack,
3211 "ipv4: Invalid header for route get request");
3212 return -EINVAL;
3213 }
3214
3215 if (!netlink_strict_get_check(skb))
3216 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3217 rtm_ipv4_policy, extack);
3218
3219 rtm = nlmsg_data(nlh);
3220 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3221 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3222 rtm->rtm_table || rtm->rtm_protocol ||
3223 rtm->rtm_scope || rtm->rtm_type) {
3224 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3225 return -EINVAL;
3226 }
3227
3228 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3229 RTM_F_LOOKUP_TABLE |
3230 RTM_F_FIB_MATCH)) {
3231 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3232 return -EINVAL;
3233 }
3234
3235 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3236 rtm_ipv4_policy, extack);
3237 if (err)
3238 return err;
3239
3240 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3241 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3242 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3243 return -EINVAL;
3244 }
3245
3246 for (i = 0; i <= RTA_MAX; i++) {
3247 if (!tb[i])
3248 continue;
3249
3250 switch (i) {
3251 case RTA_IIF:
3252 case RTA_OIF:
3253 case RTA_SRC:
3254 case RTA_DST:
3255 case RTA_IP_PROTO:
3256 case RTA_SPORT:
3257 case RTA_DPORT:
3258 case RTA_MARK:
3259 case RTA_UID:
3260 break;
3261 default:
3262 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3263 return -EINVAL;
3264 }
3265 }
3266
3267 return 0;
3268}
3269
3270static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3271 struct netlink_ext_ack *extack)
3272{
3273 struct net *net = sock_net(in_skb->sk);
3274 struct nlattr *tb[RTA_MAX+1];
3275 u32 table_id = RT_TABLE_MAIN;
3276 __be16 sport = 0, dport = 0;
3277 struct fib_result res = {};
3278 u8 ip_proto = IPPROTO_UDP;
3279 struct rtable *rt = NULL;
3280 struct sk_buff *skb;
3281 struct rtmsg *rtm;
3282 struct flowi4 fl4 = {};
3283 __be32 dst = 0;
3284 __be32 src = 0;
3285 kuid_t uid;
3286 u32 iif;
3287 int err;
3288 int mark;
3289
3290 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3291 if (err < 0)
3292 return err;
3293
3294 rtm = nlmsg_data(nlh);
3295 src = nla_get_in_addr_default(tb[RTA_SRC], 0);
3296 dst = nla_get_in_addr_default(tb[RTA_DST], 0);
3297 iif = nla_get_u32_default(tb[RTA_IIF], 0);
3298 mark = nla_get_u32_default(tb[RTA_MARK], 0);
3299 if (tb[RTA_UID])
3300 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3301 else
3302 uid = (iif ? INVALID_UID : current_uid());
3303
3304 if (tb[RTA_IP_PROTO]) {
3305 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3306 &ip_proto, AF_INET, extack);
3307 if (err)
3308 return err;
3309 }
3310
3311 if (tb[RTA_SPORT])
3312 sport = nla_get_be16(tb[RTA_SPORT]);
3313
3314 if (tb[RTA_DPORT])
3315 dport = nla_get_be16(tb[RTA_DPORT]);
3316
3317 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3318 if (!skb)
3319 return -ENOBUFS;
3320
3321 fl4.daddr = dst;
3322 fl4.saddr = src;
3323 fl4.flowi4_tos = rtm->rtm_tos & INET_DSCP_MASK;
3324 fl4.flowi4_oif = nla_get_u32_default(tb[RTA_OIF], 0);
3325 fl4.flowi4_mark = mark;
3326 fl4.flowi4_uid = uid;
3327 if (sport)
3328 fl4.fl4_sport = sport;
3329 if (dport)
3330 fl4.fl4_dport = dport;
3331 fl4.flowi4_proto = ip_proto;
3332
3333 rcu_read_lock();
3334
3335 if (iif) {
3336 struct net_device *dev;
3337
3338 dev = dev_get_by_index_rcu(net, iif);
3339 if (!dev) {
3340 err = -ENODEV;
3341 goto errout_rcu;
3342 }
3343
3344 fl4.flowi4_iif = iif; /* for rt_fill_info */
3345 skb->dev = dev;
3346 skb->mark = mark;
3347 err = ip_route_input_rcu(skb, dst, src,
3348 inet_dsfield_to_dscp(rtm->rtm_tos),
3349 dev, &res) ? -EINVAL : 0;
3350
3351 rt = skb_rtable(skb);
3352 if (err == 0 && rt->dst.error)
3353 err = -rt->dst.error;
3354 } else {
3355 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3356 skb->dev = net->loopback_dev;
3357 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3358 err = 0;
3359 if (IS_ERR(rt))
3360 err = PTR_ERR(rt);
3361 else
3362 skb_dst_set(skb, &rt->dst);
3363 }
3364
3365 if (err)
3366 goto errout_rcu;
3367
3368 if (rtm->rtm_flags & RTM_F_NOTIFY)
3369 rt->rt_flags |= RTCF_NOTIFY;
3370
3371 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3372 table_id = res.table ? res.table->tb_id : 0;
3373
3374 /* reset skb for netlink reply msg */
3375 skb_trim(skb, 0);
3376 skb_reset_network_header(skb);
3377 skb_reset_transport_header(skb);
3378 skb_reset_mac_header(skb);
3379
3380 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3381 struct fib_rt_info fri;
3382
3383 if (!res.fi) {
3384 err = fib_props[res.type].error;
3385 if (!err)
3386 err = -EHOSTUNREACH;
3387 goto errout_rcu;
3388 }
3389 fri.fi = res.fi;
3390 fri.tb_id = table_id;
3391 fri.dst = res.prefix;
3392 fri.dst_len = res.prefixlen;
3393 fri.dscp = res.dscp;
3394 fri.type = rt->rt_type;
3395 fri.offload = 0;
3396 fri.trap = 0;
3397 fri.offload_failed = 0;
3398 if (res.fa_head) {
3399 struct fib_alias *fa;
3400
3401 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3402 u8 slen = 32 - fri.dst_len;
3403
3404 if (fa->fa_slen == slen &&
3405 fa->tb_id == fri.tb_id &&
3406 fa->fa_dscp == fri.dscp &&
3407 fa->fa_info == res.fi &&
3408 fa->fa_type == fri.type) {
3409 fri.offload = READ_ONCE(fa->offload);
3410 fri.trap = READ_ONCE(fa->trap);
3411 fri.offload_failed =
3412 READ_ONCE(fa->offload_failed);
3413 break;
3414 }
3415 }
3416 }
3417 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3418 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3419 } else {
3420 err = rt_fill_info(net, dst, src, rt, table_id, res.dscp, &fl4,
3421 skb, NETLINK_CB(in_skb).portid,
3422 nlh->nlmsg_seq, 0);
3423 }
3424 if (err < 0)
3425 goto errout_rcu;
3426
3427 rcu_read_unlock();
3428
3429 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3430
3431errout_free:
3432 return err;
3433errout_rcu:
3434 rcu_read_unlock();
3435 kfree_skb(skb);
3436 goto errout_free;
3437}
3438
3439void ip_rt_multicast_event(struct in_device *in_dev)
3440{
3441 rt_cache_flush(dev_net(in_dev->dev));
3442}
3443
3444#ifdef CONFIG_SYSCTL
3445static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3446static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3447static int ip_rt_gc_elasticity __read_mostly = 8;
3448static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3449
3450static int ipv4_sysctl_rtcache_flush(const struct ctl_table *__ctl, int write,
3451 void *buffer, size_t *lenp, loff_t *ppos)
3452{
3453 struct net *net = (struct net *)__ctl->extra1;
3454
3455 if (write) {
3456 rt_cache_flush(net);
3457 fnhe_genid_bump(net);
3458 return 0;
3459 }
3460
3461 return -EINVAL;
3462}
3463
3464static struct ctl_table ipv4_route_table[] = {
3465 {
3466 .procname = "gc_thresh",
3467 .data = &ipv4_dst_ops.gc_thresh,
3468 .maxlen = sizeof(int),
3469 .mode = 0644,
3470 .proc_handler = proc_dointvec,
3471 },
3472 {
3473 .procname = "max_size",
3474 .data = &ip_rt_max_size,
3475 .maxlen = sizeof(int),
3476 .mode = 0644,
3477 .proc_handler = proc_dointvec,
3478 },
3479 {
3480 /* Deprecated. Use gc_min_interval_ms */
3481
3482 .procname = "gc_min_interval",
3483 .data = &ip_rt_gc_min_interval,
3484 .maxlen = sizeof(int),
3485 .mode = 0644,
3486 .proc_handler = proc_dointvec_jiffies,
3487 },
3488 {
3489 .procname = "gc_min_interval_ms",
3490 .data = &ip_rt_gc_min_interval,
3491 .maxlen = sizeof(int),
3492 .mode = 0644,
3493 .proc_handler = proc_dointvec_ms_jiffies,
3494 },
3495 {
3496 .procname = "gc_timeout",
3497 .data = &ip_rt_gc_timeout,
3498 .maxlen = sizeof(int),
3499 .mode = 0644,
3500 .proc_handler = proc_dointvec_jiffies,
3501 },
3502 {
3503 .procname = "gc_interval",
3504 .data = &ip_rt_gc_interval,
3505 .maxlen = sizeof(int),
3506 .mode = 0644,
3507 .proc_handler = proc_dointvec_jiffies,
3508 },
3509 {
3510 .procname = "redirect_load",
3511 .data = &ip_rt_redirect_load,
3512 .maxlen = sizeof(int),
3513 .mode = 0644,
3514 .proc_handler = proc_dointvec,
3515 },
3516 {
3517 .procname = "redirect_number",
3518 .data = &ip_rt_redirect_number,
3519 .maxlen = sizeof(int),
3520 .mode = 0644,
3521 .proc_handler = proc_dointvec,
3522 },
3523 {
3524 .procname = "redirect_silence",
3525 .data = &ip_rt_redirect_silence,
3526 .maxlen = sizeof(int),
3527 .mode = 0644,
3528 .proc_handler = proc_dointvec,
3529 },
3530 {
3531 .procname = "error_cost",
3532 .data = &ip_rt_error_cost,
3533 .maxlen = sizeof(int),
3534 .mode = 0644,
3535 .proc_handler = proc_dointvec,
3536 },
3537 {
3538 .procname = "error_burst",
3539 .data = &ip_rt_error_burst,
3540 .maxlen = sizeof(int),
3541 .mode = 0644,
3542 .proc_handler = proc_dointvec,
3543 },
3544 {
3545 .procname = "gc_elasticity",
3546 .data = &ip_rt_gc_elasticity,
3547 .maxlen = sizeof(int),
3548 .mode = 0644,
3549 .proc_handler = proc_dointvec,
3550 },
3551};
3552
3553static const char ipv4_route_flush_procname[] = "flush";
3554
3555static struct ctl_table ipv4_route_netns_table[] = {
3556 {
3557 .procname = ipv4_route_flush_procname,
3558 .maxlen = sizeof(int),
3559 .mode = 0200,
3560 .proc_handler = ipv4_sysctl_rtcache_flush,
3561 },
3562 {
3563 .procname = "min_pmtu",
3564 .data = &init_net.ipv4.ip_rt_min_pmtu,
3565 .maxlen = sizeof(int),
3566 .mode = 0644,
3567 .proc_handler = proc_dointvec_minmax,
3568 .extra1 = &ip_min_valid_pmtu,
3569 },
3570 {
3571 .procname = "mtu_expires",
3572 .data = &init_net.ipv4.ip_rt_mtu_expires,
3573 .maxlen = sizeof(int),
3574 .mode = 0644,
3575 .proc_handler = proc_dointvec_jiffies,
3576 },
3577 {
3578 .procname = "min_adv_mss",
3579 .data = &init_net.ipv4.ip_rt_min_advmss,
3580 .maxlen = sizeof(int),
3581 .mode = 0644,
3582 .proc_handler = proc_dointvec,
3583 },
3584};
3585
3586static __net_init int sysctl_route_net_init(struct net *net)
3587{
3588 struct ctl_table *tbl;
3589 size_t table_size = ARRAY_SIZE(ipv4_route_netns_table);
3590
3591 tbl = ipv4_route_netns_table;
3592 if (!net_eq(net, &init_net)) {
3593 int i;
3594
3595 tbl = kmemdup(tbl, sizeof(ipv4_route_netns_table), GFP_KERNEL);
3596 if (!tbl)
3597 goto err_dup;
3598
3599 /* Don't export non-whitelisted sysctls to unprivileged users */
3600 if (net->user_ns != &init_user_ns) {
3601 if (tbl[0].procname != ipv4_route_flush_procname)
3602 table_size = 0;
3603 }
3604
3605 /* Update the variables to point into the current struct net
3606 * except for the first element flush
3607 */
3608 for (i = 1; i < table_size; i++)
3609 tbl[i].data += (void *)net - (void *)&init_net;
3610 }
3611 tbl[0].extra1 = net;
3612
3613 net->ipv4.route_hdr = register_net_sysctl_sz(net, "net/ipv4/route",
3614 tbl, table_size);
3615 if (!net->ipv4.route_hdr)
3616 goto err_reg;
3617 return 0;
3618
3619err_reg:
3620 if (tbl != ipv4_route_netns_table)
3621 kfree(tbl);
3622err_dup:
3623 return -ENOMEM;
3624}
3625
3626static __net_exit void sysctl_route_net_exit(struct net *net)
3627{
3628 const struct ctl_table *tbl;
3629
3630 tbl = net->ipv4.route_hdr->ctl_table_arg;
3631 unregister_net_sysctl_table(net->ipv4.route_hdr);
3632 BUG_ON(tbl == ipv4_route_netns_table);
3633 kfree(tbl);
3634}
3635
3636static __net_initdata struct pernet_operations sysctl_route_ops = {
3637 .init = sysctl_route_net_init,
3638 .exit = sysctl_route_net_exit,
3639};
3640#endif
3641
3642static __net_init int netns_ip_rt_init(struct net *net)
3643{
3644 /* Set default value for namespaceified sysctls */
3645 net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU;
3646 net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES;
3647 net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS;
3648 return 0;
3649}
3650
3651static struct pernet_operations __net_initdata ip_rt_ops = {
3652 .init = netns_ip_rt_init,
3653};
3654
3655static __net_init int rt_genid_init(struct net *net)
3656{
3657 atomic_set(&net->ipv4.rt_genid, 0);
3658 atomic_set(&net->fnhe_genid, 0);
3659 atomic_set(&net->ipv4.dev_addr_genid, get_random_u32());
3660 return 0;
3661}
3662
3663static __net_initdata struct pernet_operations rt_genid_ops = {
3664 .init = rt_genid_init,
3665};
3666
3667static int __net_init ipv4_inetpeer_init(struct net *net)
3668{
3669 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3670
3671 if (!bp)
3672 return -ENOMEM;
3673 inet_peer_base_init(bp);
3674 net->ipv4.peers = bp;
3675 return 0;
3676}
3677
3678static void __net_exit ipv4_inetpeer_exit(struct net *net)
3679{
3680 struct inet_peer_base *bp = net->ipv4.peers;
3681
3682 net->ipv4.peers = NULL;
3683 inetpeer_invalidate_tree(bp);
3684 kfree(bp);
3685}
3686
3687static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3688 .init = ipv4_inetpeer_init,
3689 .exit = ipv4_inetpeer_exit,
3690};
3691
3692#ifdef CONFIG_IP_ROUTE_CLASSID
3693struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3694#endif /* CONFIG_IP_ROUTE_CLASSID */
3695
3696static const struct rtnl_msg_handler ip_rt_rtnl_msg_handlers[] __initconst = {
3697 {.protocol = PF_INET, .msgtype = RTM_GETROUTE,
3698 .doit = inet_rtm_getroute, .flags = RTNL_FLAG_DOIT_UNLOCKED},
3699};
3700
3701int __init ip_rt_init(void)
3702{
3703 void *idents_hash;
3704 int cpu;
3705
3706 /* For modern hosts, this will use 2 MB of memory */
3707 idents_hash = alloc_large_system_hash("IP idents",
3708 sizeof(*ip_idents) + sizeof(*ip_tstamps),
3709 0,
3710 16, /* one bucket per 64 KB */
3711 HASH_ZERO,
3712 NULL,
3713 &ip_idents_mask,
3714 2048,
3715 256*1024);
3716
3717 ip_idents = idents_hash;
3718
3719 get_random_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
3720
3721 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3722
3723 for_each_possible_cpu(cpu) {
3724 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3725
3726 INIT_LIST_HEAD(&ul->head);
3727 spin_lock_init(&ul->lock);
3728 }
3729#ifdef CONFIG_IP_ROUTE_CLASSID
3730 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3731 if (!ip_rt_acct)
3732 panic("IP: failed to allocate ip_rt_acct\n");
3733#endif
3734
3735 ipv4_dst_ops.kmem_cachep = KMEM_CACHE(rtable,
3736 SLAB_HWCACHE_ALIGN | SLAB_PANIC);
3737
3738 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3739
3740 if (dst_entries_init(&ipv4_dst_ops) < 0)
3741 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3742
3743 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3744 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3745
3746 ipv4_dst_ops.gc_thresh = ~0;
3747 ip_rt_max_size = INT_MAX;
3748
3749 devinet_init();
3750 ip_fib_init();
3751
3752 if (ip_rt_proc_init())
3753 pr_err("Unable to create route proc files\n");
3754#ifdef CONFIG_XFRM
3755 xfrm_init();
3756 xfrm4_init();
3757#endif
3758 rtnl_register_many(ip_rt_rtnl_msg_handlers);
3759
3760#ifdef CONFIG_SYSCTL
3761 register_pernet_subsys(&sysctl_route_ops);
3762#endif
3763 register_pernet_subsys(&ip_rt_ops);
3764 register_pernet_subsys(&rt_genid_ops);
3765 register_pernet_subsys(&ipv4_inetpeer_ops);
3766 return 0;
3767}
3768
3769#ifdef CONFIG_SYSCTL
3770/*
3771 * We really need to sanitize the damn ipv4 init order, then all
3772 * this nonsense will go away.
3773 */
3774void __init ip_static_sysctl_init(void)
3775{
3776 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3777}
3778#endif
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * ROUTE - implementation of the IP router.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Alan Cox, <gw4pts@gw4pts.ampr.org>
11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
13 *
14 * Fixes:
15 * Alan Cox : Verify area fixes.
16 * Alan Cox : cli() protects routing changes
17 * Rui Oliveira : ICMP routing table updates
18 * (rco@di.uminho.pt) Routing table insertion and update
19 * Linus Torvalds : Rewrote bits to be sensible
20 * Alan Cox : Added BSD route gw semantics
21 * Alan Cox : Super /proc >4K
22 * Alan Cox : MTU in route table
23 * Alan Cox : MSS actually. Also added the window
24 * clamper.
25 * Sam Lantinga : Fixed route matching in rt_del()
26 * Alan Cox : Routing cache support.
27 * Alan Cox : Removed compatibility cruft.
28 * Alan Cox : RTF_REJECT support.
29 * Alan Cox : TCP irtt support.
30 * Jonathan Naylor : Added Metric support.
31 * Miquel van Smoorenburg : BSD API fixes.
32 * Miquel van Smoorenburg : Metrics.
33 * Alan Cox : Use __u32 properly
34 * Alan Cox : Aligned routing errors more closely with BSD
35 * our system is still very different.
36 * Alan Cox : Faster /proc handling
37 * Alexey Kuznetsov : Massive rework to support tree based routing,
38 * routing caches and better behaviour.
39 *
40 * Olaf Erb : irtt wasn't being copied right.
41 * Bjorn Ekwall : Kerneld route support.
42 * Alan Cox : Multicast fixed (I hope)
43 * Pavel Krauz : Limited broadcast fixed
44 * Mike McLagan : Routing by source
45 * Alexey Kuznetsov : End of old history. Split to fib.c and
46 * route.c and rewritten from scratch.
47 * Andi Kleen : Load-limit warning messages.
48 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
52 * Marc Boucher : routing by fwmark
53 * Robert Olsson : Added rt_cache statistics
54 * Arnaldo C. Melo : Convert proc stuff to seq_file
55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
57 * Ilia Sotnikov : Removed TOS from hash calculations
58 *
59 * This program is free software; you can redistribute it and/or
60 * modify it under the terms of the GNU General Public License
61 * as published by the Free Software Foundation; either version
62 * 2 of the License, or (at your option) any later version.
63 */
64
65#define pr_fmt(fmt) "IPv4: " fmt
66
67#include <linux/module.h>
68#include <linux/uaccess.h>
69#include <linux/bitops.h>
70#include <linux/types.h>
71#include <linux/kernel.h>
72#include <linux/mm.h>
73#include <linux/string.h>
74#include <linux/socket.h>
75#include <linux/sockios.h>
76#include <linux/errno.h>
77#include <linux/in.h>
78#include <linux/inet.h>
79#include <linux/netdevice.h>
80#include <linux/proc_fs.h>
81#include <linux/init.h>
82#include <linux/skbuff.h>
83#include <linux/inetdevice.h>
84#include <linux/igmp.h>
85#include <linux/pkt_sched.h>
86#include <linux/mroute.h>
87#include <linux/netfilter_ipv4.h>
88#include <linux/random.h>
89#include <linux/rcupdate.h>
90#include <linux/times.h>
91#include <linux/slab.h>
92#include <linux/jhash.h>
93#include <net/dst.h>
94#include <net/dst_metadata.h>
95#include <net/net_namespace.h>
96#include <net/protocol.h>
97#include <net/ip.h>
98#include <net/route.h>
99#include <net/inetpeer.h>
100#include <net/sock.h>
101#include <net/ip_fib.h>
102#include <net/arp.h>
103#include <net/tcp.h>
104#include <net/icmp.h>
105#include <net/xfrm.h>
106#include <net/lwtunnel.h>
107#include <net/netevent.h>
108#include <net/rtnetlink.h>
109#ifdef CONFIG_SYSCTL
110#include <linux/sysctl.h>
111#include <linux/kmemleak.h>
112#endif
113#include <net/secure_seq.h>
114#include <net/ip_tunnels.h>
115#include <net/l3mdev.h>
116
117#define RT_FL_TOS(oldflp4) \
118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
119
120#define RT_GC_TIMEOUT (300*HZ)
121
122static int ip_rt_max_size;
123static int ip_rt_redirect_number __read_mostly = 9;
124static int ip_rt_redirect_load __read_mostly = HZ / 50;
125static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
126static int ip_rt_error_cost __read_mostly = HZ;
127static int ip_rt_error_burst __read_mostly = 5 * HZ;
128static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
129static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
130static int ip_rt_min_advmss __read_mostly = 256;
131
132static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
133/*
134 * Interface to generic destination cache.
135 */
136
137static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
138static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
139static unsigned int ipv4_mtu(const struct dst_entry *dst);
140static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
141static void ipv4_link_failure(struct sk_buff *skb);
142static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
143 struct sk_buff *skb, u32 mtu);
144static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146static void ipv4_dst_destroy(struct dst_entry *dst);
147
148static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
149{
150 WARN_ON(1);
151 return NULL;
152}
153
154static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
155 struct sk_buff *skb,
156 const void *daddr);
157
158static 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};
172
173#define ECN_OR_COST(class) TC_PRIO_##class
174
175const __u8 ip_tos2prio[16] = {
176 TC_PRIO_BESTEFFORT,
177 ECN_OR_COST(BESTEFFORT),
178 TC_PRIO_BESTEFFORT,
179 ECN_OR_COST(BESTEFFORT),
180 TC_PRIO_BULK,
181 ECN_OR_COST(BULK),
182 TC_PRIO_BULK,
183 ECN_OR_COST(BULK),
184 TC_PRIO_INTERACTIVE,
185 ECN_OR_COST(INTERACTIVE),
186 TC_PRIO_INTERACTIVE,
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE_BULK,
189 ECN_OR_COST(INTERACTIVE_BULK),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK)
192};
193EXPORT_SYMBOL(ip_tos2prio);
194
195static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
196#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
197
198#ifdef CONFIG_PROC_FS
199static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
200{
201 if (*pos)
202 return NULL;
203 return SEQ_START_TOKEN;
204}
205
206static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
207{
208 ++*pos;
209 return NULL;
210}
211
212static void rt_cache_seq_stop(struct seq_file *seq, void *v)
213{
214}
215
216static int rt_cache_seq_show(struct seq_file *seq, void *v)
217{
218 if (v == SEQ_START_TOKEN)
219 seq_printf(seq, "%-127s\n",
220 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
221 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
222 "HHUptod\tSpecDst");
223 return 0;
224}
225
226static const struct seq_operations rt_cache_seq_ops = {
227 .start = rt_cache_seq_start,
228 .next = rt_cache_seq_next,
229 .stop = rt_cache_seq_stop,
230 .show = rt_cache_seq_show,
231};
232
233static int rt_cache_seq_open(struct inode *inode, struct file *file)
234{
235 return seq_open(file, &rt_cache_seq_ops);
236}
237
238static const struct file_operations rt_cache_seq_fops = {
239 .owner = THIS_MODULE,
240 .open = rt_cache_seq_open,
241 .read = seq_read,
242 .llseek = seq_lseek,
243 .release = seq_release,
244};
245
246
247static 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
263static 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
277static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
278{
279
280}
281
282static 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
316static 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
324static int rt_cpu_seq_open(struct inode *inode, struct file *file)
325{
326 return seq_open(file, &rt_cpu_seq_ops);
327}
328
329static const struct file_operations rt_cpu_seq_fops = {
330 .owner = THIS_MODULE,
331 .open = rt_cpu_seq_open,
332 .read = seq_read,
333 .llseek = seq_lseek,
334 .release = seq_release,
335};
336
337#ifdef CONFIG_IP_ROUTE_CLASSID
338static int rt_acct_proc_show(struct seq_file *m, void *v)
339{
340 struct ip_rt_acct *dst, *src;
341 unsigned int i, j;
342
343 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
344 if (!dst)
345 return -ENOMEM;
346
347 for_each_possible_cpu(i) {
348 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
349 for (j = 0; j < 256; j++) {
350 dst[j].o_bytes += src[j].o_bytes;
351 dst[j].o_packets += src[j].o_packets;
352 dst[j].i_bytes += src[j].i_bytes;
353 dst[j].i_packets += src[j].i_packets;
354 }
355 }
356
357 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
358 kfree(dst);
359 return 0;
360}
361
362static int rt_acct_proc_open(struct inode *inode, struct file *file)
363{
364 return single_open(file, rt_acct_proc_show, NULL);
365}
366
367static const struct file_operations rt_acct_proc_fops = {
368 .owner = THIS_MODULE,
369 .open = rt_acct_proc_open,
370 .read = seq_read,
371 .llseek = seq_lseek,
372 .release = single_release,
373};
374#endif
375
376static int __net_init ip_rt_do_proc_init(struct net *net)
377{
378 struct proc_dir_entry *pde;
379
380 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
381 &rt_cache_seq_fops);
382 if (!pde)
383 goto err1;
384
385 pde = proc_create("rt_cache", S_IRUGO,
386 net->proc_net_stat, &rt_cpu_seq_fops);
387 if (!pde)
388 goto err2;
389
390#ifdef CONFIG_IP_ROUTE_CLASSID
391 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
392 if (!pde)
393 goto err3;
394#endif
395 return 0;
396
397#ifdef CONFIG_IP_ROUTE_CLASSID
398err3:
399 remove_proc_entry("rt_cache", net->proc_net_stat);
400#endif
401err2:
402 remove_proc_entry("rt_cache", net->proc_net);
403err1:
404 return -ENOMEM;
405}
406
407static void __net_exit ip_rt_do_proc_exit(struct net *net)
408{
409 remove_proc_entry("rt_cache", net->proc_net_stat);
410 remove_proc_entry("rt_cache", net->proc_net);
411#ifdef CONFIG_IP_ROUTE_CLASSID
412 remove_proc_entry("rt_acct", net->proc_net);
413#endif
414}
415
416static struct pernet_operations ip_rt_proc_ops __net_initdata = {
417 .init = ip_rt_do_proc_init,
418 .exit = ip_rt_do_proc_exit,
419};
420
421static int __init ip_rt_proc_init(void)
422{
423 return register_pernet_subsys(&ip_rt_proc_ops);
424}
425
426#else
427static inline int ip_rt_proc_init(void)
428{
429 return 0;
430}
431#endif /* CONFIG_PROC_FS */
432
433static inline bool rt_is_expired(const struct rtable *rth)
434{
435 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
436}
437
438void rt_cache_flush(struct net *net)
439{
440 rt_genid_bump_ipv4(net);
441}
442
443static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
444 struct sk_buff *skb,
445 const void *daddr)
446{
447 struct net_device *dev = dst->dev;
448 const __be32 *pkey = daddr;
449 const struct rtable *rt;
450 struct neighbour *n;
451
452 rt = (const struct rtable *) dst;
453 if (rt->rt_gateway)
454 pkey = (const __be32 *) &rt->rt_gateway;
455 else if (skb)
456 pkey = &ip_hdr(skb)->daddr;
457
458 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
459 if (n)
460 return n;
461 return neigh_create(&arp_tbl, pkey, dev);
462}
463
464#define IP_IDENTS_SZ 2048u
465
466static atomic_t *ip_idents __read_mostly;
467static u32 *ip_tstamps __read_mostly;
468
469/* In order to protect privacy, we add a perturbation to identifiers
470 * if one generator is seldom used. This makes hard for an attacker
471 * to infer how many packets were sent between two points in time.
472 */
473u32 ip_idents_reserve(u32 hash, int segs)
474{
475 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
476 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
477 u32 old = ACCESS_ONCE(*p_tstamp);
478 u32 now = (u32)jiffies;
479 u32 new, delta = 0;
480
481 if (old != now && cmpxchg(p_tstamp, old, now) == old)
482 delta = prandom_u32_max(now - old);
483
484 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
485 do {
486 old = (u32)atomic_read(p_id);
487 new = old + delta + segs;
488 } while (atomic_cmpxchg(p_id, old, new) != old);
489
490 return new - segs;
491}
492EXPORT_SYMBOL(ip_idents_reserve);
493
494void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
495{
496 static u32 ip_idents_hashrnd __read_mostly;
497 u32 hash, id;
498
499 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
500
501 hash = jhash_3words((__force u32)iph->daddr,
502 (__force u32)iph->saddr,
503 iph->protocol ^ net_hash_mix(net),
504 ip_idents_hashrnd);
505 id = ip_idents_reserve(hash, segs);
506 iph->id = htons(id);
507}
508EXPORT_SYMBOL(__ip_select_ident);
509
510static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
511 const struct sock *sk,
512 const struct iphdr *iph,
513 int oif, u8 tos,
514 u8 prot, u32 mark, int flow_flags)
515{
516 if (sk) {
517 const struct inet_sock *inet = inet_sk(sk);
518
519 oif = sk->sk_bound_dev_if;
520 mark = sk->sk_mark;
521 tos = RT_CONN_FLAGS(sk);
522 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
523 }
524 flowi4_init_output(fl4, oif, mark, tos,
525 RT_SCOPE_UNIVERSE, prot,
526 flow_flags,
527 iph->daddr, iph->saddr, 0, 0,
528 sock_net_uid(net, sk));
529}
530
531static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
532 const struct sock *sk)
533{
534 const struct net *net = dev_net(skb->dev);
535 const struct iphdr *iph = ip_hdr(skb);
536 int oif = skb->dev->ifindex;
537 u8 tos = RT_TOS(iph->tos);
538 u8 prot = iph->protocol;
539 u32 mark = skb->mark;
540
541 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
542}
543
544static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
545{
546 const struct inet_sock *inet = inet_sk(sk);
547 const struct ip_options_rcu *inet_opt;
548 __be32 daddr = inet->inet_daddr;
549
550 rcu_read_lock();
551 inet_opt = rcu_dereference(inet->inet_opt);
552 if (inet_opt && inet_opt->opt.srr)
553 daddr = inet_opt->opt.faddr;
554 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
555 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
556 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
557 inet_sk_flowi_flags(sk),
558 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
559 rcu_read_unlock();
560}
561
562static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
563 const struct sk_buff *skb)
564{
565 if (skb)
566 build_skb_flow_key(fl4, skb, sk);
567 else
568 build_sk_flow_key(fl4, sk);
569}
570
571static inline void rt_free(struct rtable *rt)
572{
573 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
574}
575
576static DEFINE_SPINLOCK(fnhe_lock);
577
578static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
579{
580 struct rtable *rt;
581
582 rt = rcu_dereference(fnhe->fnhe_rth_input);
583 if (rt) {
584 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
585 rt_free(rt);
586 }
587 rt = rcu_dereference(fnhe->fnhe_rth_output);
588 if (rt) {
589 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
590 rt_free(rt);
591 }
592}
593
594static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
595{
596 struct fib_nh_exception *fnhe, *oldest;
597
598 oldest = rcu_dereference(hash->chain);
599 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
600 fnhe = rcu_dereference(fnhe->fnhe_next)) {
601 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
602 oldest = fnhe;
603 }
604 fnhe_flush_routes(oldest);
605 return oldest;
606}
607
608static inline u32 fnhe_hashfun(__be32 daddr)
609{
610 static u32 fnhe_hashrnd __read_mostly;
611 u32 hval;
612
613 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
614 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
615 return hash_32(hval, FNHE_HASH_SHIFT);
616}
617
618static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
619{
620 rt->rt_pmtu = fnhe->fnhe_pmtu;
621 rt->dst.expires = fnhe->fnhe_expires;
622
623 if (fnhe->fnhe_gw) {
624 rt->rt_flags |= RTCF_REDIRECTED;
625 rt->rt_gateway = fnhe->fnhe_gw;
626 rt->rt_uses_gateway = 1;
627 }
628}
629
630static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
631 u32 pmtu, unsigned long expires)
632{
633 struct fnhe_hash_bucket *hash;
634 struct fib_nh_exception *fnhe;
635 struct rtable *rt;
636 unsigned int i;
637 int depth;
638 u32 hval = fnhe_hashfun(daddr);
639
640 spin_lock_bh(&fnhe_lock);
641
642 hash = rcu_dereference(nh->nh_exceptions);
643 if (!hash) {
644 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
645 if (!hash)
646 goto out_unlock;
647 rcu_assign_pointer(nh->nh_exceptions, hash);
648 }
649
650 hash += hval;
651
652 depth = 0;
653 for (fnhe = rcu_dereference(hash->chain); fnhe;
654 fnhe = rcu_dereference(fnhe->fnhe_next)) {
655 if (fnhe->fnhe_daddr == daddr)
656 break;
657 depth++;
658 }
659
660 if (fnhe) {
661 if (gw)
662 fnhe->fnhe_gw = gw;
663 if (pmtu) {
664 fnhe->fnhe_pmtu = pmtu;
665 fnhe->fnhe_expires = max(1UL, expires);
666 }
667 /* Update all cached dsts too */
668 rt = rcu_dereference(fnhe->fnhe_rth_input);
669 if (rt)
670 fill_route_from_fnhe(rt, fnhe);
671 rt = rcu_dereference(fnhe->fnhe_rth_output);
672 if (rt)
673 fill_route_from_fnhe(rt, fnhe);
674 } else {
675 if (depth > FNHE_RECLAIM_DEPTH)
676 fnhe = fnhe_oldest(hash);
677 else {
678 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
679 if (!fnhe)
680 goto out_unlock;
681
682 fnhe->fnhe_next = hash->chain;
683 rcu_assign_pointer(hash->chain, fnhe);
684 }
685 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
686 fnhe->fnhe_daddr = daddr;
687 fnhe->fnhe_gw = gw;
688 fnhe->fnhe_pmtu = pmtu;
689 fnhe->fnhe_expires = expires;
690
691 /* Exception created; mark the cached routes for the nexthop
692 * stale, so anyone caching it rechecks if this exception
693 * applies to them.
694 */
695 rt = rcu_dereference(nh->nh_rth_input);
696 if (rt)
697 rt->dst.obsolete = DST_OBSOLETE_KILL;
698
699 for_each_possible_cpu(i) {
700 struct rtable __rcu **prt;
701 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
702 rt = rcu_dereference(*prt);
703 if (rt)
704 rt->dst.obsolete = DST_OBSOLETE_KILL;
705 }
706 }
707
708 fnhe->fnhe_stamp = jiffies;
709
710out_unlock:
711 spin_unlock_bh(&fnhe_lock);
712}
713
714static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
715 bool kill_route)
716{
717 __be32 new_gw = icmp_hdr(skb)->un.gateway;
718 __be32 old_gw = ip_hdr(skb)->saddr;
719 struct net_device *dev = skb->dev;
720 struct in_device *in_dev;
721 struct fib_result res;
722 struct neighbour *n;
723 struct net *net;
724
725 switch (icmp_hdr(skb)->code & 7) {
726 case ICMP_REDIR_NET:
727 case ICMP_REDIR_NETTOS:
728 case ICMP_REDIR_HOST:
729 case ICMP_REDIR_HOSTTOS:
730 break;
731
732 default:
733 return;
734 }
735
736 if (rt->rt_gateway != old_gw)
737 return;
738
739 in_dev = __in_dev_get_rcu(dev);
740 if (!in_dev)
741 return;
742
743 net = dev_net(dev);
744 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
745 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
746 ipv4_is_zeronet(new_gw))
747 goto reject_redirect;
748
749 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
750 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
751 goto reject_redirect;
752 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
753 goto reject_redirect;
754 } else {
755 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
756 goto reject_redirect;
757 }
758
759 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
760 if (!n)
761 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
762 if (!IS_ERR(n)) {
763 if (!(n->nud_state & NUD_VALID)) {
764 neigh_event_send(n, NULL);
765 } else {
766 if (fib_lookup(net, fl4, &res, 0) == 0) {
767 struct fib_nh *nh = &FIB_RES_NH(res);
768
769 update_or_create_fnhe(nh, fl4->daddr, new_gw,
770 0, jiffies + ip_rt_gc_timeout);
771 }
772 if (kill_route)
773 rt->dst.obsolete = DST_OBSOLETE_KILL;
774 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
775 }
776 neigh_release(n);
777 }
778 return;
779
780reject_redirect:
781#ifdef CONFIG_IP_ROUTE_VERBOSE
782 if (IN_DEV_LOG_MARTIANS(in_dev)) {
783 const struct iphdr *iph = (const struct iphdr *) skb->data;
784 __be32 daddr = iph->daddr;
785 __be32 saddr = iph->saddr;
786
787 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
788 " Advised path = %pI4 -> %pI4\n",
789 &old_gw, dev->name, &new_gw,
790 &saddr, &daddr);
791 }
792#endif
793 ;
794}
795
796static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
797{
798 struct rtable *rt;
799 struct flowi4 fl4;
800 const struct iphdr *iph = (const struct iphdr *) skb->data;
801 struct net *net = dev_net(skb->dev);
802 int oif = skb->dev->ifindex;
803 u8 tos = RT_TOS(iph->tos);
804 u8 prot = iph->protocol;
805 u32 mark = skb->mark;
806
807 rt = (struct rtable *) dst;
808
809 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
810 __ip_do_redirect(rt, skb, &fl4, true);
811}
812
813static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
814{
815 struct rtable *rt = (struct rtable *)dst;
816 struct dst_entry *ret = dst;
817
818 if (rt) {
819 if (dst->obsolete > 0) {
820 ip_rt_put(rt);
821 ret = NULL;
822 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
823 rt->dst.expires) {
824 ip_rt_put(rt);
825 ret = NULL;
826 }
827 }
828 return ret;
829}
830
831/*
832 * Algorithm:
833 * 1. The first ip_rt_redirect_number redirects are sent
834 * with exponential backoff, then we stop sending them at all,
835 * assuming that the host ignores our redirects.
836 * 2. If we did not see packets requiring redirects
837 * during ip_rt_redirect_silence, we assume that the host
838 * forgot redirected route and start to send redirects again.
839 *
840 * This algorithm is much cheaper and more intelligent than dumb load limiting
841 * in icmp.c.
842 *
843 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
844 * and "frag. need" (breaks PMTU discovery) in icmp.c.
845 */
846
847void ip_rt_send_redirect(struct sk_buff *skb)
848{
849 struct rtable *rt = skb_rtable(skb);
850 struct in_device *in_dev;
851 struct inet_peer *peer;
852 struct net *net;
853 int log_martians;
854 int vif;
855
856 rcu_read_lock();
857 in_dev = __in_dev_get_rcu(rt->dst.dev);
858 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
859 rcu_read_unlock();
860 return;
861 }
862 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
863 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
864 rcu_read_unlock();
865
866 net = dev_net(rt->dst.dev);
867 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
868 if (!peer) {
869 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
870 rt_nexthop(rt, ip_hdr(skb)->daddr));
871 return;
872 }
873
874 /* No redirected packets during ip_rt_redirect_silence;
875 * reset the algorithm.
876 */
877 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
878 peer->rate_tokens = 0;
879
880 /* Too many ignored redirects; do not send anything
881 * set dst.rate_last to the last seen redirected packet.
882 */
883 if (peer->rate_tokens >= ip_rt_redirect_number) {
884 peer->rate_last = jiffies;
885 goto out_put_peer;
886 }
887
888 /* Check for load limit; set rate_last to the latest sent
889 * redirect.
890 */
891 if (peer->rate_tokens == 0 ||
892 time_after(jiffies,
893 (peer->rate_last +
894 (ip_rt_redirect_load << peer->rate_tokens)))) {
895 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
896
897 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
898 peer->rate_last = jiffies;
899 ++peer->rate_tokens;
900#ifdef CONFIG_IP_ROUTE_VERBOSE
901 if (log_martians &&
902 peer->rate_tokens == ip_rt_redirect_number)
903 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
904 &ip_hdr(skb)->saddr, inet_iif(skb),
905 &ip_hdr(skb)->daddr, &gw);
906#endif
907 }
908out_put_peer:
909 inet_putpeer(peer);
910}
911
912static int ip_error(struct sk_buff *skb)
913{
914 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
915 struct rtable *rt = skb_rtable(skb);
916 struct inet_peer *peer;
917 unsigned long now;
918 struct net *net;
919 bool send;
920 int code;
921
922 /* IP on this device is disabled. */
923 if (!in_dev)
924 goto out;
925
926 net = dev_net(rt->dst.dev);
927 if (!IN_DEV_FORWARD(in_dev)) {
928 switch (rt->dst.error) {
929 case EHOSTUNREACH:
930 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
931 break;
932
933 case ENETUNREACH:
934 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
935 break;
936 }
937 goto out;
938 }
939
940 switch (rt->dst.error) {
941 case EINVAL:
942 default:
943 goto out;
944 case EHOSTUNREACH:
945 code = ICMP_HOST_UNREACH;
946 break;
947 case ENETUNREACH:
948 code = ICMP_NET_UNREACH;
949 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
950 break;
951 case EACCES:
952 code = ICMP_PKT_FILTERED;
953 break;
954 }
955
956 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
957 l3mdev_master_ifindex(skb->dev), 1);
958
959 send = true;
960 if (peer) {
961 now = jiffies;
962 peer->rate_tokens += now - peer->rate_last;
963 if (peer->rate_tokens > ip_rt_error_burst)
964 peer->rate_tokens = ip_rt_error_burst;
965 peer->rate_last = now;
966 if (peer->rate_tokens >= ip_rt_error_cost)
967 peer->rate_tokens -= ip_rt_error_cost;
968 else
969 send = false;
970 inet_putpeer(peer);
971 }
972 if (send)
973 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
974
975out: kfree_skb(skb);
976 return 0;
977}
978
979static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
980{
981 struct dst_entry *dst = &rt->dst;
982 struct fib_result res;
983
984 if (dst_metric_locked(dst, RTAX_MTU))
985 return;
986
987 if (ipv4_mtu(dst) < mtu)
988 return;
989
990 if (mtu < ip_rt_min_pmtu)
991 mtu = ip_rt_min_pmtu;
992
993 if (rt->rt_pmtu == mtu &&
994 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
995 return;
996
997 rcu_read_lock();
998 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
999 struct fib_nh *nh = &FIB_RES_NH(res);
1000
1001 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
1002 jiffies + ip_rt_mtu_expires);
1003 }
1004 rcu_read_unlock();
1005}
1006
1007static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1008 struct sk_buff *skb, u32 mtu)
1009{
1010 struct rtable *rt = (struct rtable *) dst;
1011 struct flowi4 fl4;
1012
1013 ip_rt_build_flow_key(&fl4, sk, skb);
1014 __ip_rt_update_pmtu(rt, &fl4, mtu);
1015}
1016
1017void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1018 int oif, u32 mark, u8 protocol, int flow_flags)
1019{
1020 const struct iphdr *iph = (const struct iphdr *) skb->data;
1021 struct flowi4 fl4;
1022 struct rtable *rt;
1023
1024 if (!mark)
1025 mark = IP4_REPLY_MARK(net, skb->mark);
1026
1027 __build_flow_key(net, &fl4, NULL, iph, oif,
1028 RT_TOS(iph->tos), protocol, mark, flow_flags);
1029 rt = __ip_route_output_key(net, &fl4);
1030 if (!IS_ERR(rt)) {
1031 __ip_rt_update_pmtu(rt, &fl4, mtu);
1032 ip_rt_put(rt);
1033 }
1034}
1035EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1036
1037static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1038{
1039 const struct iphdr *iph = (const struct iphdr *) skb->data;
1040 struct flowi4 fl4;
1041 struct rtable *rt;
1042
1043 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1044
1045 if (!fl4.flowi4_mark)
1046 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1047
1048 rt = __ip_route_output_key(sock_net(sk), &fl4);
1049 if (!IS_ERR(rt)) {
1050 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051 ip_rt_put(rt);
1052 }
1053}
1054
1055void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1056{
1057 const struct iphdr *iph = (const struct iphdr *) skb->data;
1058 struct flowi4 fl4;
1059 struct rtable *rt;
1060 struct dst_entry *odst = NULL;
1061 bool new = false;
1062 struct net *net = sock_net(sk);
1063
1064 bh_lock_sock(sk);
1065
1066 if (!ip_sk_accept_pmtu(sk))
1067 goto out;
1068
1069 odst = sk_dst_get(sk);
1070
1071 if (sock_owned_by_user(sk) || !odst) {
1072 __ipv4_sk_update_pmtu(skb, sk, mtu);
1073 goto out;
1074 }
1075
1076 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1077
1078 rt = (struct rtable *)odst;
1079 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1080 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1081 if (IS_ERR(rt))
1082 goto out;
1083
1084 new = true;
1085 }
1086
1087 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1088
1089 if (!dst_check(&rt->dst, 0)) {
1090 if (new)
1091 dst_release(&rt->dst);
1092
1093 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1094 if (IS_ERR(rt))
1095 goto out;
1096
1097 new = true;
1098 }
1099
1100 if (new)
1101 sk_dst_set(sk, &rt->dst);
1102
1103out:
1104 bh_unlock_sock(sk);
1105 dst_release(odst);
1106}
1107EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1108
1109void ipv4_redirect(struct sk_buff *skb, struct net *net,
1110 int oif, u32 mark, u8 protocol, int flow_flags)
1111{
1112 const struct iphdr *iph = (const struct iphdr *) skb->data;
1113 struct flowi4 fl4;
1114 struct rtable *rt;
1115
1116 __build_flow_key(net, &fl4, NULL, iph, oif,
1117 RT_TOS(iph->tos), protocol, mark, flow_flags);
1118 rt = __ip_route_output_key(net, &fl4);
1119 if (!IS_ERR(rt)) {
1120 __ip_do_redirect(rt, skb, &fl4, false);
1121 ip_rt_put(rt);
1122 }
1123}
1124EXPORT_SYMBOL_GPL(ipv4_redirect);
1125
1126void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1127{
1128 const struct iphdr *iph = (const struct iphdr *) skb->data;
1129 struct flowi4 fl4;
1130 struct rtable *rt;
1131 struct net *net = sock_net(sk);
1132
1133 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1134 rt = __ip_route_output_key(net, &fl4);
1135 if (!IS_ERR(rt)) {
1136 __ip_do_redirect(rt, skb, &fl4, false);
1137 ip_rt_put(rt);
1138 }
1139}
1140EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1141
1142static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1143{
1144 struct rtable *rt = (struct rtable *) dst;
1145
1146 /* All IPV4 dsts are created with ->obsolete set to the value
1147 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1148 * into this function always.
1149 *
1150 * When a PMTU/redirect information update invalidates a route,
1151 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1152 * DST_OBSOLETE_DEAD by dst_free().
1153 */
1154 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1155 return NULL;
1156 return dst;
1157}
1158
1159static void ipv4_link_failure(struct sk_buff *skb)
1160{
1161 struct rtable *rt;
1162
1163 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1164
1165 rt = skb_rtable(skb);
1166 if (rt)
1167 dst_set_expires(&rt->dst, 0);
1168}
1169
1170static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1171{
1172 pr_debug("%s: %pI4 -> %pI4, %s\n",
1173 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1174 skb->dev ? skb->dev->name : "?");
1175 kfree_skb(skb);
1176 WARN_ON(1);
1177 return 0;
1178}
1179
1180/*
1181 We do not cache source address of outgoing interface,
1182 because it is used only by IP RR, TS and SRR options,
1183 so that it out of fast path.
1184
1185 BTW remember: "addr" is allowed to be not aligned
1186 in IP options!
1187 */
1188
1189void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1190{
1191 __be32 src;
1192
1193 if (rt_is_output_route(rt))
1194 src = ip_hdr(skb)->saddr;
1195 else {
1196 struct fib_result res;
1197 struct flowi4 fl4;
1198 struct iphdr *iph;
1199
1200 iph = ip_hdr(skb);
1201
1202 memset(&fl4, 0, sizeof(fl4));
1203 fl4.daddr = iph->daddr;
1204 fl4.saddr = iph->saddr;
1205 fl4.flowi4_tos = RT_TOS(iph->tos);
1206 fl4.flowi4_oif = rt->dst.dev->ifindex;
1207 fl4.flowi4_iif = skb->dev->ifindex;
1208 fl4.flowi4_mark = skb->mark;
1209
1210 rcu_read_lock();
1211 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1212 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1213 else
1214 src = inet_select_addr(rt->dst.dev,
1215 rt_nexthop(rt, iph->daddr),
1216 RT_SCOPE_UNIVERSE);
1217 rcu_read_unlock();
1218 }
1219 memcpy(addr, &src, 4);
1220}
1221
1222#ifdef CONFIG_IP_ROUTE_CLASSID
1223static void set_class_tag(struct rtable *rt, u32 tag)
1224{
1225 if (!(rt->dst.tclassid & 0xFFFF))
1226 rt->dst.tclassid |= tag & 0xFFFF;
1227 if (!(rt->dst.tclassid & 0xFFFF0000))
1228 rt->dst.tclassid |= tag & 0xFFFF0000;
1229}
1230#endif
1231
1232static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1233{
1234 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1235
1236 if (advmss == 0) {
1237 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1238 ip_rt_min_advmss);
1239 if (advmss > 65535 - 40)
1240 advmss = 65535 - 40;
1241 }
1242 return advmss;
1243}
1244
1245static unsigned int ipv4_mtu(const struct dst_entry *dst)
1246{
1247 const struct rtable *rt = (const struct rtable *) dst;
1248 unsigned int mtu = rt->rt_pmtu;
1249
1250 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1251 mtu = dst_metric_raw(dst, RTAX_MTU);
1252
1253 if (mtu)
1254 return mtu;
1255
1256 mtu = dst->dev->mtu;
1257
1258 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1259 if (rt->rt_uses_gateway && mtu > 576)
1260 mtu = 576;
1261 }
1262
1263 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1264
1265 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1266}
1267
1268static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1269{
1270 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1271 struct fib_nh_exception *fnhe;
1272 u32 hval;
1273
1274 if (!hash)
1275 return NULL;
1276
1277 hval = fnhe_hashfun(daddr);
1278
1279 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1280 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1281 if (fnhe->fnhe_daddr == daddr)
1282 return fnhe;
1283 }
1284 return NULL;
1285}
1286
1287static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1288 __be32 daddr)
1289{
1290 bool ret = false;
1291
1292 spin_lock_bh(&fnhe_lock);
1293
1294 if (daddr == fnhe->fnhe_daddr) {
1295 struct rtable __rcu **porig;
1296 struct rtable *orig;
1297 int genid = fnhe_genid(dev_net(rt->dst.dev));
1298
1299 if (rt_is_input_route(rt))
1300 porig = &fnhe->fnhe_rth_input;
1301 else
1302 porig = &fnhe->fnhe_rth_output;
1303 orig = rcu_dereference(*porig);
1304
1305 if (fnhe->fnhe_genid != genid) {
1306 fnhe->fnhe_genid = genid;
1307 fnhe->fnhe_gw = 0;
1308 fnhe->fnhe_pmtu = 0;
1309 fnhe->fnhe_expires = 0;
1310 fnhe_flush_routes(fnhe);
1311 orig = NULL;
1312 }
1313 fill_route_from_fnhe(rt, fnhe);
1314 if (!rt->rt_gateway)
1315 rt->rt_gateway = daddr;
1316
1317 if (!(rt->dst.flags & DST_NOCACHE)) {
1318 rcu_assign_pointer(*porig, rt);
1319 if (orig)
1320 rt_free(orig);
1321 ret = true;
1322 }
1323
1324 fnhe->fnhe_stamp = jiffies;
1325 }
1326 spin_unlock_bh(&fnhe_lock);
1327
1328 return ret;
1329}
1330
1331static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1332{
1333 struct rtable *orig, *prev, **p;
1334 bool ret = true;
1335
1336 if (rt_is_input_route(rt)) {
1337 p = (struct rtable **)&nh->nh_rth_input;
1338 } else {
1339 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1340 }
1341 orig = *p;
1342
1343 prev = cmpxchg(p, orig, rt);
1344 if (prev == orig) {
1345 if (orig)
1346 rt_free(orig);
1347 } else
1348 ret = false;
1349
1350 return ret;
1351}
1352
1353struct uncached_list {
1354 spinlock_t lock;
1355 struct list_head head;
1356};
1357
1358static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1359
1360static void rt_add_uncached_list(struct rtable *rt)
1361{
1362 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1363
1364 rt->rt_uncached_list = ul;
1365
1366 spin_lock_bh(&ul->lock);
1367 list_add_tail(&rt->rt_uncached, &ul->head);
1368 spin_unlock_bh(&ul->lock);
1369}
1370
1371static void ipv4_dst_destroy(struct dst_entry *dst)
1372{
1373 struct rtable *rt = (struct rtable *) dst;
1374
1375 if (!list_empty(&rt->rt_uncached)) {
1376 struct uncached_list *ul = rt->rt_uncached_list;
1377
1378 spin_lock_bh(&ul->lock);
1379 list_del(&rt->rt_uncached);
1380 spin_unlock_bh(&ul->lock);
1381 }
1382}
1383
1384void rt_flush_dev(struct net_device *dev)
1385{
1386 struct net *net = dev_net(dev);
1387 struct rtable *rt;
1388 int cpu;
1389
1390 for_each_possible_cpu(cpu) {
1391 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1392
1393 spin_lock_bh(&ul->lock);
1394 list_for_each_entry(rt, &ul->head, rt_uncached) {
1395 if (rt->dst.dev != dev)
1396 continue;
1397 rt->dst.dev = net->loopback_dev;
1398 dev_hold(rt->dst.dev);
1399 dev_put(dev);
1400 }
1401 spin_unlock_bh(&ul->lock);
1402 }
1403}
1404
1405static bool rt_cache_valid(const struct rtable *rt)
1406{
1407 return rt &&
1408 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1409 !rt_is_expired(rt);
1410}
1411
1412static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1413 const struct fib_result *res,
1414 struct fib_nh_exception *fnhe,
1415 struct fib_info *fi, u16 type, u32 itag)
1416{
1417 bool cached = false;
1418
1419 if (fi) {
1420 struct fib_nh *nh = &FIB_RES_NH(*res);
1421
1422 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1423 rt->rt_gateway = nh->nh_gw;
1424 rt->rt_uses_gateway = 1;
1425 }
1426 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1427#ifdef CONFIG_IP_ROUTE_CLASSID
1428 rt->dst.tclassid = nh->nh_tclassid;
1429#endif
1430 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1431 if (unlikely(fnhe))
1432 cached = rt_bind_exception(rt, fnhe, daddr);
1433 else if (!(rt->dst.flags & DST_NOCACHE))
1434 cached = rt_cache_route(nh, rt);
1435 if (unlikely(!cached)) {
1436 /* Routes we intend to cache in nexthop exception or
1437 * FIB nexthop have the DST_NOCACHE bit clear.
1438 * However, if we are unsuccessful at storing this
1439 * route into the cache we really need to set it.
1440 */
1441 rt->dst.flags |= DST_NOCACHE;
1442 if (!rt->rt_gateway)
1443 rt->rt_gateway = daddr;
1444 rt_add_uncached_list(rt);
1445 }
1446 } else
1447 rt_add_uncached_list(rt);
1448
1449#ifdef CONFIG_IP_ROUTE_CLASSID
1450#ifdef CONFIG_IP_MULTIPLE_TABLES
1451 set_class_tag(rt, res->tclassid);
1452#endif
1453 set_class_tag(rt, itag);
1454#endif
1455}
1456
1457struct rtable *rt_dst_alloc(struct net_device *dev,
1458 unsigned int flags, u16 type,
1459 bool nopolicy, bool noxfrm, bool will_cache)
1460{
1461 struct rtable *rt;
1462
1463 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1464 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1465 (nopolicy ? DST_NOPOLICY : 0) |
1466 (noxfrm ? DST_NOXFRM : 0));
1467
1468 if (rt) {
1469 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1470 rt->rt_flags = flags;
1471 rt->rt_type = type;
1472 rt->rt_is_input = 0;
1473 rt->rt_iif = 0;
1474 rt->rt_pmtu = 0;
1475 rt->rt_gateway = 0;
1476 rt->rt_uses_gateway = 0;
1477 rt->rt_table_id = 0;
1478 INIT_LIST_HEAD(&rt->rt_uncached);
1479
1480 rt->dst.output = ip_output;
1481 if (flags & RTCF_LOCAL)
1482 rt->dst.input = ip_local_deliver;
1483 }
1484
1485 return rt;
1486}
1487EXPORT_SYMBOL(rt_dst_alloc);
1488
1489/* called in rcu_read_lock() section */
1490static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1491 u8 tos, struct net_device *dev, int our)
1492{
1493 struct rtable *rth;
1494 struct in_device *in_dev = __in_dev_get_rcu(dev);
1495 unsigned int flags = RTCF_MULTICAST;
1496 u32 itag = 0;
1497 int err;
1498
1499 /* Primary sanity checks. */
1500
1501 if (!in_dev)
1502 return -EINVAL;
1503
1504 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1505 skb->protocol != htons(ETH_P_IP))
1506 goto e_inval;
1507
1508 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1509 goto e_inval;
1510
1511 if (ipv4_is_zeronet(saddr)) {
1512 if (!ipv4_is_local_multicast(daddr))
1513 goto e_inval;
1514 } else {
1515 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1516 in_dev, &itag);
1517 if (err < 0)
1518 goto e_err;
1519 }
1520 if (our)
1521 flags |= RTCF_LOCAL;
1522
1523 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1524 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1525 if (!rth)
1526 goto e_nobufs;
1527
1528#ifdef CONFIG_IP_ROUTE_CLASSID
1529 rth->dst.tclassid = itag;
1530#endif
1531 rth->dst.output = ip_rt_bug;
1532 rth->rt_is_input= 1;
1533
1534#ifdef CONFIG_IP_MROUTE
1535 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1536 rth->dst.input = ip_mr_input;
1537#endif
1538 RT_CACHE_STAT_INC(in_slow_mc);
1539
1540 skb_dst_set(skb, &rth->dst);
1541 return 0;
1542
1543e_nobufs:
1544 return -ENOBUFS;
1545e_inval:
1546 return -EINVAL;
1547e_err:
1548 return err;
1549}
1550
1551
1552static void ip_handle_martian_source(struct net_device *dev,
1553 struct in_device *in_dev,
1554 struct sk_buff *skb,
1555 __be32 daddr,
1556 __be32 saddr)
1557{
1558 RT_CACHE_STAT_INC(in_martian_src);
1559#ifdef CONFIG_IP_ROUTE_VERBOSE
1560 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1561 /*
1562 * RFC1812 recommendation, if source is martian,
1563 * the only hint is MAC header.
1564 */
1565 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1566 &daddr, &saddr, dev->name);
1567 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1568 print_hex_dump(KERN_WARNING, "ll header: ",
1569 DUMP_PREFIX_OFFSET, 16, 1,
1570 skb_mac_header(skb),
1571 dev->hard_header_len, true);
1572 }
1573 }
1574#endif
1575}
1576
1577static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1578{
1579 struct fnhe_hash_bucket *hash;
1580 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1581 u32 hval = fnhe_hashfun(daddr);
1582
1583 spin_lock_bh(&fnhe_lock);
1584
1585 hash = rcu_dereference_protected(nh->nh_exceptions,
1586 lockdep_is_held(&fnhe_lock));
1587 hash += hval;
1588
1589 fnhe_p = &hash->chain;
1590 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1591 while (fnhe) {
1592 if (fnhe->fnhe_daddr == daddr) {
1593 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1594 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1595 fnhe_flush_routes(fnhe);
1596 kfree_rcu(fnhe, rcu);
1597 break;
1598 }
1599 fnhe_p = &fnhe->fnhe_next;
1600 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1601 lockdep_is_held(&fnhe_lock));
1602 }
1603
1604 spin_unlock_bh(&fnhe_lock);
1605}
1606
1607static void set_lwt_redirect(struct rtable *rth)
1608{
1609 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1610 rth->dst.lwtstate->orig_output = rth->dst.output;
1611 rth->dst.output = lwtunnel_output;
1612 }
1613
1614 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1615 rth->dst.lwtstate->orig_input = rth->dst.input;
1616 rth->dst.input = lwtunnel_input;
1617 }
1618}
1619
1620/* called in rcu_read_lock() section */
1621static int __mkroute_input(struct sk_buff *skb,
1622 const struct fib_result *res,
1623 struct in_device *in_dev,
1624 __be32 daddr, __be32 saddr, u32 tos)
1625{
1626 struct fib_nh_exception *fnhe;
1627 struct rtable *rth;
1628 int err;
1629 struct in_device *out_dev;
1630 bool do_cache;
1631 u32 itag = 0;
1632
1633 /* get a working reference to the output device */
1634 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1635 if (!out_dev) {
1636 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1637 return -EINVAL;
1638 }
1639
1640 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1641 in_dev->dev, in_dev, &itag);
1642 if (err < 0) {
1643 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1644 saddr);
1645
1646 goto cleanup;
1647 }
1648
1649 do_cache = res->fi && !itag;
1650 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1651 skb->protocol == htons(ETH_P_IP) &&
1652 (IN_DEV_SHARED_MEDIA(out_dev) ||
1653 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1654 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1655
1656 if (skb->protocol != htons(ETH_P_IP)) {
1657 /* Not IP (i.e. ARP). Do not create route, if it is
1658 * invalid for proxy arp. DNAT routes are always valid.
1659 *
1660 * Proxy arp feature have been extended to allow, ARP
1661 * replies back to the same interface, to support
1662 * Private VLAN switch technologies. See arp.c.
1663 */
1664 if (out_dev == in_dev &&
1665 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1666 err = -EINVAL;
1667 goto cleanup;
1668 }
1669 }
1670
1671 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1672 if (do_cache) {
1673 if (fnhe) {
1674 rth = rcu_dereference(fnhe->fnhe_rth_input);
1675 if (rth && rth->dst.expires &&
1676 time_after(jiffies, rth->dst.expires)) {
1677 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1678 fnhe = NULL;
1679 } else {
1680 goto rt_cache;
1681 }
1682 }
1683
1684 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1685
1686rt_cache:
1687 if (rt_cache_valid(rth)) {
1688 skb_dst_set_noref(skb, &rth->dst);
1689 goto out;
1690 }
1691 }
1692
1693 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1694 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1695 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1696 if (!rth) {
1697 err = -ENOBUFS;
1698 goto cleanup;
1699 }
1700
1701 rth->rt_is_input = 1;
1702 if (res->table)
1703 rth->rt_table_id = res->table->tb_id;
1704 RT_CACHE_STAT_INC(in_slow_tot);
1705
1706 rth->dst.input = ip_forward;
1707
1708 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1709 set_lwt_redirect(rth);
1710 skb_dst_set(skb, &rth->dst);
1711out:
1712 err = 0;
1713 cleanup:
1714 return err;
1715}
1716
1717#ifdef CONFIG_IP_ROUTE_MULTIPATH
1718
1719/* To make ICMP packets follow the right flow, the multipath hash is
1720 * calculated from the inner IP addresses in reverse order.
1721 */
1722static int ip_multipath_icmp_hash(struct sk_buff *skb)
1723{
1724 const struct iphdr *outer_iph = ip_hdr(skb);
1725 struct icmphdr _icmph;
1726 const struct icmphdr *icmph;
1727 struct iphdr _inner_iph;
1728 const struct iphdr *inner_iph;
1729
1730 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1731 goto standard_hash;
1732
1733 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1734 &_icmph);
1735 if (!icmph)
1736 goto standard_hash;
1737
1738 if (icmph->type != ICMP_DEST_UNREACH &&
1739 icmph->type != ICMP_REDIRECT &&
1740 icmph->type != ICMP_TIME_EXCEEDED &&
1741 icmph->type != ICMP_PARAMETERPROB) {
1742 goto standard_hash;
1743 }
1744
1745 inner_iph = skb_header_pointer(skb,
1746 outer_iph->ihl * 4 + sizeof(_icmph),
1747 sizeof(_inner_iph), &_inner_iph);
1748 if (!inner_iph)
1749 goto standard_hash;
1750
1751 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1752
1753standard_hash:
1754 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1755}
1756
1757#endif /* CONFIG_IP_ROUTE_MULTIPATH */
1758
1759static int ip_mkroute_input(struct sk_buff *skb,
1760 struct fib_result *res,
1761 const struct flowi4 *fl4,
1762 struct in_device *in_dev,
1763 __be32 daddr, __be32 saddr, u32 tos)
1764{
1765#ifdef CONFIG_IP_ROUTE_MULTIPATH
1766 if (res->fi && res->fi->fib_nhs > 1) {
1767 int h;
1768
1769 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1770 h = ip_multipath_icmp_hash(skb);
1771 else
1772 h = fib_multipath_hash(saddr, daddr);
1773 fib_select_multipath(res, h);
1774 }
1775#endif
1776
1777 /* create a routing cache entry */
1778 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1779}
1780
1781/*
1782 * NOTE. We drop all the packets that has local source
1783 * addresses, because every properly looped back packet
1784 * must have correct destination already attached by output routine.
1785 *
1786 * Such approach solves two big problems:
1787 * 1. Not simplex devices are handled properly.
1788 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1789 * called with rcu_read_lock()
1790 */
1791
1792static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1793 u8 tos, struct net_device *dev)
1794{
1795 struct fib_result res;
1796 struct in_device *in_dev = __in_dev_get_rcu(dev);
1797 struct ip_tunnel_info *tun_info;
1798 struct flowi4 fl4;
1799 unsigned int flags = 0;
1800 u32 itag = 0;
1801 struct rtable *rth;
1802 int err = -EINVAL;
1803 struct net *net = dev_net(dev);
1804 bool do_cache;
1805
1806 /* IP on this device is disabled. */
1807
1808 if (!in_dev)
1809 goto out;
1810
1811 /* Check for the most weird martians, which can be not detected
1812 by fib_lookup.
1813 */
1814
1815 tun_info = skb_tunnel_info(skb);
1816 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1817 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1818 else
1819 fl4.flowi4_tun_key.tun_id = 0;
1820 skb_dst_drop(skb);
1821
1822 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1823 goto martian_source;
1824
1825 res.fi = NULL;
1826 res.table = NULL;
1827 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1828 goto brd_input;
1829
1830 /* Accept zero addresses only to limited broadcast;
1831 * I even do not know to fix it or not. Waiting for complains :-)
1832 */
1833 if (ipv4_is_zeronet(saddr))
1834 goto martian_source;
1835
1836 if (ipv4_is_zeronet(daddr))
1837 goto martian_destination;
1838
1839 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1840 * and call it once if daddr or/and saddr are loopback addresses
1841 */
1842 if (ipv4_is_loopback(daddr)) {
1843 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1844 goto martian_destination;
1845 } else if (ipv4_is_loopback(saddr)) {
1846 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1847 goto martian_source;
1848 }
1849
1850 /*
1851 * Now we are ready to route packet.
1852 */
1853 fl4.flowi4_oif = 0;
1854 fl4.flowi4_iif = dev->ifindex;
1855 fl4.flowi4_mark = skb->mark;
1856 fl4.flowi4_tos = tos;
1857 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1858 fl4.flowi4_flags = 0;
1859 fl4.daddr = daddr;
1860 fl4.saddr = saddr;
1861 fl4.flowi4_uid = sock_net_uid(net, NULL);
1862 err = fib_lookup(net, &fl4, &res, 0);
1863 if (err != 0) {
1864 if (!IN_DEV_FORWARD(in_dev))
1865 err = -EHOSTUNREACH;
1866 goto no_route;
1867 }
1868
1869 if (res.type == RTN_BROADCAST)
1870 goto brd_input;
1871
1872 if (res.type == RTN_LOCAL) {
1873 err = fib_validate_source(skb, saddr, daddr, tos,
1874 0, dev, in_dev, &itag);
1875 if (err < 0)
1876 goto martian_source;
1877 goto local_input;
1878 }
1879
1880 if (!IN_DEV_FORWARD(in_dev)) {
1881 err = -EHOSTUNREACH;
1882 goto no_route;
1883 }
1884 if (res.type != RTN_UNICAST)
1885 goto martian_destination;
1886
1887 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1888out: return err;
1889
1890brd_input:
1891 if (skb->protocol != htons(ETH_P_IP))
1892 goto e_inval;
1893
1894 if (!ipv4_is_zeronet(saddr)) {
1895 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1896 in_dev, &itag);
1897 if (err < 0)
1898 goto martian_source;
1899 }
1900 flags |= RTCF_BROADCAST;
1901 res.type = RTN_BROADCAST;
1902 RT_CACHE_STAT_INC(in_brd);
1903
1904local_input:
1905 do_cache = false;
1906 if (res.fi) {
1907 if (!itag) {
1908 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1909 if (rt_cache_valid(rth)) {
1910 skb_dst_set_noref(skb, &rth->dst);
1911 err = 0;
1912 goto out;
1913 }
1914 do_cache = true;
1915 }
1916 }
1917
1918 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
1919 flags | RTCF_LOCAL, res.type,
1920 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1921 if (!rth)
1922 goto e_nobufs;
1923
1924 rth->dst.output= ip_rt_bug;
1925#ifdef CONFIG_IP_ROUTE_CLASSID
1926 rth->dst.tclassid = itag;
1927#endif
1928 rth->rt_is_input = 1;
1929 if (res.table)
1930 rth->rt_table_id = res.table->tb_id;
1931
1932 RT_CACHE_STAT_INC(in_slow_tot);
1933 if (res.type == RTN_UNREACHABLE) {
1934 rth->dst.input= ip_error;
1935 rth->dst.error= -err;
1936 rth->rt_flags &= ~RTCF_LOCAL;
1937 }
1938
1939 if (do_cache) {
1940 struct fib_nh *nh = &FIB_RES_NH(res);
1941
1942 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1943 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1944 WARN_ON(rth->dst.input == lwtunnel_input);
1945 rth->dst.lwtstate->orig_input = rth->dst.input;
1946 rth->dst.input = lwtunnel_input;
1947 }
1948
1949 if (unlikely(!rt_cache_route(nh, rth))) {
1950 rth->dst.flags |= DST_NOCACHE;
1951 rt_add_uncached_list(rth);
1952 }
1953 }
1954 skb_dst_set(skb, &rth->dst);
1955 err = 0;
1956 goto out;
1957
1958no_route:
1959 RT_CACHE_STAT_INC(in_no_route);
1960 res.type = RTN_UNREACHABLE;
1961 res.fi = NULL;
1962 res.table = NULL;
1963 goto local_input;
1964
1965 /*
1966 * Do not cache martian addresses: they should be logged (RFC1812)
1967 */
1968martian_destination:
1969 RT_CACHE_STAT_INC(in_martian_dst);
1970#ifdef CONFIG_IP_ROUTE_VERBOSE
1971 if (IN_DEV_LOG_MARTIANS(in_dev))
1972 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1973 &daddr, &saddr, dev->name);
1974#endif
1975
1976e_inval:
1977 err = -EINVAL;
1978 goto out;
1979
1980e_nobufs:
1981 err = -ENOBUFS;
1982 goto out;
1983
1984martian_source:
1985 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1986 goto out;
1987}
1988
1989int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1990 u8 tos, struct net_device *dev)
1991{
1992 int res;
1993
1994 tos &= IPTOS_RT_MASK;
1995 rcu_read_lock();
1996
1997 /* Multicast recognition logic is moved from route cache to here.
1998 The problem was that too many Ethernet cards have broken/missing
1999 hardware multicast filters :-( As result the host on multicasting
2000 network acquires a lot of useless route cache entries, sort of
2001 SDR messages from all the world. Now we try to get rid of them.
2002 Really, provided software IP multicast filter is organized
2003 reasonably (at least, hashed), it does not result in a slowdown
2004 comparing with route cache reject entries.
2005 Note, that multicast routers are not affected, because
2006 route cache entry is created eventually.
2007 */
2008 if (ipv4_is_multicast(daddr)) {
2009 struct in_device *in_dev = __in_dev_get_rcu(dev);
2010 int our = 0;
2011
2012 if (in_dev)
2013 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2014 ip_hdr(skb)->protocol);
2015
2016 /* check l3 master if no match yet */
2017 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2018 struct in_device *l3_in_dev;
2019
2020 l3_in_dev = __in_dev_get_rcu(skb->dev);
2021 if (l3_in_dev)
2022 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2023 ip_hdr(skb)->protocol);
2024 }
2025
2026 res = -EINVAL;
2027 if (our
2028#ifdef CONFIG_IP_MROUTE
2029 ||
2030 (!ipv4_is_local_multicast(daddr) &&
2031 IN_DEV_MFORWARD(in_dev))
2032#endif
2033 ) {
2034 res = ip_route_input_mc(skb, daddr, saddr,
2035 tos, dev, our);
2036 }
2037 rcu_read_unlock();
2038 return res;
2039 }
2040 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
2041 rcu_read_unlock();
2042 return res;
2043}
2044EXPORT_SYMBOL(ip_route_input_noref);
2045
2046/* called with rcu_read_lock() */
2047static struct rtable *__mkroute_output(const struct fib_result *res,
2048 const struct flowi4 *fl4, int orig_oif,
2049 struct net_device *dev_out,
2050 unsigned int flags)
2051{
2052 struct fib_info *fi = res->fi;
2053 struct fib_nh_exception *fnhe;
2054 struct in_device *in_dev;
2055 u16 type = res->type;
2056 struct rtable *rth;
2057 bool do_cache;
2058
2059 in_dev = __in_dev_get_rcu(dev_out);
2060 if (!in_dev)
2061 return ERR_PTR(-EINVAL);
2062
2063 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2064 if (ipv4_is_loopback(fl4->saddr) &&
2065 !(dev_out->flags & IFF_LOOPBACK) &&
2066 !netif_is_l3_master(dev_out))
2067 return ERR_PTR(-EINVAL);
2068
2069 if (ipv4_is_lbcast(fl4->daddr))
2070 type = RTN_BROADCAST;
2071 else if (ipv4_is_multicast(fl4->daddr))
2072 type = RTN_MULTICAST;
2073 else if (ipv4_is_zeronet(fl4->daddr))
2074 return ERR_PTR(-EINVAL);
2075
2076 if (dev_out->flags & IFF_LOOPBACK)
2077 flags |= RTCF_LOCAL;
2078
2079 do_cache = true;
2080 if (type == RTN_BROADCAST) {
2081 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2082 fi = NULL;
2083 } else if (type == RTN_MULTICAST) {
2084 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2085 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2086 fl4->flowi4_proto))
2087 flags &= ~RTCF_LOCAL;
2088 else
2089 do_cache = false;
2090 /* If multicast route do not exist use
2091 * default one, but do not gateway in this case.
2092 * Yes, it is hack.
2093 */
2094 if (fi && res->prefixlen < 4)
2095 fi = NULL;
2096 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2097 (orig_oif != dev_out->ifindex)) {
2098 /* For local routes that require a particular output interface
2099 * we do not want to cache the result. Caching the result
2100 * causes incorrect behaviour when there are multiple source
2101 * addresses on the interface, the end result being that if the
2102 * intended recipient is waiting on that interface for the
2103 * packet he won't receive it because it will be delivered on
2104 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2105 * be set to the loopback interface as well.
2106 */
2107 fi = NULL;
2108 }
2109
2110 fnhe = NULL;
2111 do_cache &= fi != NULL;
2112 if (do_cache) {
2113 struct rtable __rcu **prth;
2114 struct fib_nh *nh = &FIB_RES_NH(*res);
2115
2116 fnhe = find_exception(nh, fl4->daddr);
2117 if (fnhe) {
2118 prth = &fnhe->fnhe_rth_output;
2119 rth = rcu_dereference(*prth);
2120 if (rth && rth->dst.expires &&
2121 time_after(jiffies, rth->dst.expires)) {
2122 ip_del_fnhe(nh, fl4->daddr);
2123 fnhe = NULL;
2124 } else {
2125 goto rt_cache;
2126 }
2127 }
2128
2129 if (unlikely(fl4->flowi4_flags &
2130 FLOWI_FLAG_KNOWN_NH &&
2131 !(nh->nh_gw &&
2132 nh->nh_scope == RT_SCOPE_LINK))) {
2133 do_cache = false;
2134 goto add;
2135 }
2136 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2137 rth = rcu_dereference(*prth);
2138
2139rt_cache:
2140 if (rt_cache_valid(rth)) {
2141 dst_hold(&rth->dst);
2142 return rth;
2143 }
2144 }
2145
2146add:
2147 rth = rt_dst_alloc(dev_out, flags, type,
2148 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2149 IN_DEV_CONF_GET(in_dev, NOXFRM),
2150 do_cache);
2151 if (!rth)
2152 return ERR_PTR(-ENOBUFS);
2153
2154 rth->rt_iif = orig_oif ? : 0;
2155 if (res->table)
2156 rth->rt_table_id = res->table->tb_id;
2157
2158 RT_CACHE_STAT_INC(out_slow_tot);
2159
2160 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2161 if (flags & RTCF_LOCAL &&
2162 !(dev_out->flags & IFF_LOOPBACK)) {
2163 rth->dst.output = ip_mc_output;
2164 RT_CACHE_STAT_INC(out_slow_mc);
2165 }
2166#ifdef CONFIG_IP_MROUTE
2167 if (type == RTN_MULTICAST) {
2168 if (IN_DEV_MFORWARD(in_dev) &&
2169 !ipv4_is_local_multicast(fl4->daddr)) {
2170 rth->dst.input = ip_mr_input;
2171 rth->dst.output = ip_mc_output;
2172 }
2173 }
2174#endif
2175 }
2176
2177 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2178 set_lwt_redirect(rth);
2179
2180 return rth;
2181}
2182
2183/*
2184 * Major route resolver routine.
2185 */
2186
2187struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2188 int mp_hash)
2189{
2190 struct net_device *dev_out = NULL;
2191 __u8 tos = RT_FL_TOS(fl4);
2192 unsigned int flags = 0;
2193 struct fib_result res;
2194 struct rtable *rth;
2195 int orig_oif;
2196 int err = -ENETUNREACH;
2197
2198 res.tclassid = 0;
2199 res.fi = NULL;
2200 res.table = NULL;
2201
2202 orig_oif = fl4->flowi4_oif;
2203
2204 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2205 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2206 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2207 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2208
2209 rcu_read_lock();
2210 if (fl4->saddr) {
2211 rth = ERR_PTR(-EINVAL);
2212 if (ipv4_is_multicast(fl4->saddr) ||
2213 ipv4_is_lbcast(fl4->saddr) ||
2214 ipv4_is_zeronet(fl4->saddr))
2215 goto out;
2216
2217 /* I removed check for oif == dev_out->oif here.
2218 It was wrong for two reasons:
2219 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2220 is assigned to multiple interfaces.
2221 2. Moreover, we are allowed to send packets with saddr
2222 of another iface. --ANK
2223 */
2224
2225 if (fl4->flowi4_oif == 0 &&
2226 (ipv4_is_multicast(fl4->daddr) ||
2227 ipv4_is_lbcast(fl4->daddr))) {
2228 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2229 dev_out = __ip_dev_find(net, fl4->saddr, false);
2230 if (!dev_out)
2231 goto out;
2232
2233 /* Special hack: user can direct multicasts
2234 and limited broadcast via necessary interface
2235 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2236 This hack is not just for fun, it allows
2237 vic,vat and friends to work.
2238 They bind socket to loopback, set ttl to zero
2239 and expect that it will work.
2240 From the viewpoint of routing cache they are broken,
2241 because we are not allowed to build multicast path
2242 with loopback source addr (look, routing cache
2243 cannot know, that ttl is zero, so that packet
2244 will not leave this host and route is valid).
2245 Luckily, this hack is good workaround.
2246 */
2247
2248 fl4->flowi4_oif = dev_out->ifindex;
2249 goto make_route;
2250 }
2251
2252 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2253 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2254 if (!__ip_dev_find(net, fl4->saddr, false))
2255 goto out;
2256 }
2257 }
2258
2259
2260 if (fl4->flowi4_oif) {
2261 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2262 rth = ERR_PTR(-ENODEV);
2263 if (!dev_out)
2264 goto out;
2265
2266 /* RACE: Check return value of inet_select_addr instead. */
2267 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2268 rth = ERR_PTR(-ENETUNREACH);
2269 goto out;
2270 }
2271 if (ipv4_is_local_multicast(fl4->daddr) ||
2272 ipv4_is_lbcast(fl4->daddr) ||
2273 fl4->flowi4_proto == IPPROTO_IGMP) {
2274 if (!fl4->saddr)
2275 fl4->saddr = inet_select_addr(dev_out, 0,
2276 RT_SCOPE_LINK);
2277 goto make_route;
2278 }
2279 if (!fl4->saddr) {
2280 if (ipv4_is_multicast(fl4->daddr))
2281 fl4->saddr = inet_select_addr(dev_out, 0,
2282 fl4->flowi4_scope);
2283 else if (!fl4->daddr)
2284 fl4->saddr = inet_select_addr(dev_out, 0,
2285 RT_SCOPE_HOST);
2286 }
2287 }
2288
2289 if (!fl4->daddr) {
2290 fl4->daddr = fl4->saddr;
2291 if (!fl4->daddr)
2292 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2293 dev_out = net->loopback_dev;
2294 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2295 res.type = RTN_LOCAL;
2296 flags |= RTCF_LOCAL;
2297 goto make_route;
2298 }
2299
2300 err = fib_lookup(net, fl4, &res, 0);
2301 if (err) {
2302 res.fi = NULL;
2303 res.table = NULL;
2304 if (fl4->flowi4_oif &&
2305 (ipv4_is_multicast(fl4->daddr) ||
2306 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2307 /* Apparently, routing tables are wrong. Assume,
2308 that the destination is on link.
2309
2310 WHY? DW.
2311 Because we are allowed to send to iface
2312 even if it has NO routes and NO assigned
2313 addresses. When oif is specified, routing
2314 tables are looked up with only one purpose:
2315 to catch if destination is gatewayed, rather than
2316 direct. Moreover, if MSG_DONTROUTE is set,
2317 we send packet, ignoring both routing tables
2318 and ifaddr state. --ANK
2319
2320
2321 We could make it even if oif is unknown,
2322 likely IPv6, but we do not.
2323 */
2324
2325 if (fl4->saddr == 0)
2326 fl4->saddr = inet_select_addr(dev_out, 0,
2327 RT_SCOPE_LINK);
2328 res.type = RTN_UNICAST;
2329 goto make_route;
2330 }
2331 rth = ERR_PTR(err);
2332 goto out;
2333 }
2334
2335 if (res.type == RTN_LOCAL) {
2336 if (!fl4->saddr) {
2337 if (res.fi->fib_prefsrc)
2338 fl4->saddr = res.fi->fib_prefsrc;
2339 else
2340 fl4->saddr = fl4->daddr;
2341 }
2342
2343 /* L3 master device is the loopback for that domain */
2344 dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev;
2345 fl4->flowi4_oif = dev_out->ifindex;
2346 flags |= RTCF_LOCAL;
2347 goto make_route;
2348 }
2349
2350 fib_select_path(net, &res, fl4, mp_hash);
2351
2352 dev_out = FIB_RES_DEV(res);
2353 fl4->flowi4_oif = dev_out->ifindex;
2354
2355
2356make_route:
2357 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2358
2359out:
2360 rcu_read_unlock();
2361 return rth;
2362}
2363EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2364
2365static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2366{
2367 return NULL;
2368}
2369
2370static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2371{
2372 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2373
2374 return mtu ? : dst->dev->mtu;
2375}
2376
2377static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2378 struct sk_buff *skb, u32 mtu)
2379{
2380}
2381
2382static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2383 struct sk_buff *skb)
2384{
2385}
2386
2387static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2388 unsigned long old)
2389{
2390 return NULL;
2391}
2392
2393static struct dst_ops ipv4_dst_blackhole_ops = {
2394 .family = AF_INET,
2395 .check = ipv4_blackhole_dst_check,
2396 .mtu = ipv4_blackhole_mtu,
2397 .default_advmss = ipv4_default_advmss,
2398 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2399 .redirect = ipv4_rt_blackhole_redirect,
2400 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2401 .neigh_lookup = ipv4_neigh_lookup,
2402};
2403
2404struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2405{
2406 struct rtable *ort = (struct rtable *) dst_orig;
2407 struct rtable *rt;
2408
2409 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2410 if (rt) {
2411 struct dst_entry *new = &rt->dst;
2412
2413 new->__use = 1;
2414 new->input = dst_discard;
2415 new->output = dst_discard_out;
2416
2417 new->dev = ort->dst.dev;
2418 if (new->dev)
2419 dev_hold(new->dev);
2420
2421 rt->rt_is_input = ort->rt_is_input;
2422 rt->rt_iif = ort->rt_iif;
2423 rt->rt_pmtu = ort->rt_pmtu;
2424
2425 rt->rt_genid = rt_genid_ipv4(net);
2426 rt->rt_flags = ort->rt_flags;
2427 rt->rt_type = ort->rt_type;
2428 rt->rt_gateway = ort->rt_gateway;
2429 rt->rt_uses_gateway = ort->rt_uses_gateway;
2430
2431 INIT_LIST_HEAD(&rt->rt_uncached);
2432 dst_free(new);
2433 }
2434
2435 dst_release(dst_orig);
2436
2437 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2438}
2439
2440struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2441 const struct sock *sk)
2442{
2443 struct rtable *rt = __ip_route_output_key(net, flp4);
2444
2445 if (IS_ERR(rt))
2446 return rt;
2447
2448 if (flp4->flowi4_proto)
2449 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2450 flowi4_to_flowi(flp4),
2451 sk, 0);
2452
2453 return rt;
2454}
2455EXPORT_SYMBOL_GPL(ip_route_output_flow);
2456
2457static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2458 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2459 u32 seq, int event, int nowait, unsigned int flags)
2460{
2461 struct rtable *rt = skb_rtable(skb);
2462 struct rtmsg *r;
2463 struct nlmsghdr *nlh;
2464 unsigned long expires = 0;
2465 u32 error;
2466 u32 metrics[RTAX_MAX];
2467
2468 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2469 if (!nlh)
2470 return -EMSGSIZE;
2471
2472 r = nlmsg_data(nlh);
2473 r->rtm_family = AF_INET;
2474 r->rtm_dst_len = 32;
2475 r->rtm_src_len = 0;
2476 r->rtm_tos = fl4->flowi4_tos;
2477 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2478 if (nla_put_u32(skb, RTA_TABLE, table_id))
2479 goto nla_put_failure;
2480 r->rtm_type = rt->rt_type;
2481 r->rtm_scope = RT_SCOPE_UNIVERSE;
2482 r->rtm_protocol = RTPROT_UNSPEC;
2483 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2484 if (rt->rt_flags & RTCF_NOTIFY)
2485 r->rtm_flags |= RTM_F_NOTIFY;
2486 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2487 r->rtm_flags |= RTCF_DOREDIRECT;
2488
2489 if (nla_put_in_addr(skb, RTA_DST, dst))
2490 goto nla_put_failure;
2491 if (src) {
2492 r->rtm_src_len = 32;
2493 if (nla_put_in_addr(skb, RTA_SRC, src))
2494 goto nla_put_failure;
2495 }
2496 if (rt->dst.dev &&
2497 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2498 goto nla_put_failure;
2499#ifdef CONFIG_IP_ROUTE_CLASSID
2500 if (rt->dst.tclassid &&
2501 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2502 goto nla_put_failure;
2503#endif
2504 if (!rt_is_input_route(rt) &&
2505 fl4->saddr != src) {
2506 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2507 goto nla_put_failure;
2508 }
2509 if (rt->rt_uses_gateway &&
2510 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2511 goto nla_put_failure;
2512
2513 expires = rt->dst.expires;
2514 if (expires) {
2515 unsigned long now = jiffies;
2516
2517 if (time_before(now, expires))
2518 expires -= now;
2519 else
2520 expires = 0;
2521 }
2522
2523 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2524 if (rt->rt_pmtu && expires)
2525 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2526 if (rtnetlink_put_metrics(skb, metrics) < 0)
2527 goto nla_put_failure;
2528
2529 if (fl4->flowi4_mark &&
2530 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2531 goto nla_put_failure;
2532
2533 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2534 nla_put_u32(skb, RTA_UID,
2535 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2536 goto nla_put_failure;
2537
2538 error = rt->dst.error;
2539
2540 if (rt_is_input_route(rt)) {
2541#ifdef CONFIG_IP_MROUTE
2542 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2543 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2544 int err = ipmr_get_route(net, skb,
2545 fl4->saddr, fl4->daddr,
2546 r, nowait, portid);
2547
2548 if (err <= 0) {
2549 if (!nowait) {
2550 if (err == 0)
2551 return 0;
2552 goto nla_put_failure;
2553 } else {
2554 if (err == -EMSGSIZE)
2555 goto nla_put_failure;
2556 error = err;
2557 }
2558 }
2559 } else
2560#endif
2561 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2562 goto nla_put_failure;
2563 }
2564
2565 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2566 goto nla_put_failure;
2567
2568 nlmsg_end(skb, nlh);
2569 return 0;
2570
2571nla_put_failure:
2572 nlmsg_cancel(skb, nlh);
2573 return -EMSGSIZE;
2574}
2575
2576static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2577{
2578 struct net *net = sock_net(in_skb->sk);
2579 struct rtmsg *rtm;
2580 struct nlattr *tb[RTA_MAX+1];
2581 struct rtable *rt = NULL;
2582 struct flowi4 fl4;
2583 __be32 dst = 0;
2584 __be32 src = 0;
2585 u32 iif;
2586 int err;
2587 int mark;
2588 struct sk_buff *skb;
2589 u32 table_id = RT_TABLE_MAIN;
2590 kuid_t uid;
2591
2592 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2593 if (err < 0)
2594 goto errout;
2595
2596 rtm = nlmsg_data(nlh);
2597
2598 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2599 if (!skb) {
2600 err = -ENOBUFS;
2601 goto errout;
2602 }
2603
2604 /* Reserve room for dummy headers, this skb can pass
2605 through good chunk of routing engine.
2606 */
2607 skb_reset_mac_header(skb);
2608 skb_reset_network_header(skb);
2609
2610 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2611 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2612 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2613
2614 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2615 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2616 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2617 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2618 if (tb[RTA_UID])
2619 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2620 else
2621 uid = (iif ? INVALID_UID : current_uid());
2622
2623 memset(&fl4, 0, sizeof(fl4));
2624 fl4.daddr = dst;
2625 fl4.saddr = src;
2626 fl4.flowi4_tos = rtm->rtm_tos;
2627 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2628 fl4.flowi4_mark = mark;
2629 fl4.flowi4_uid = uid;
2630
2631 if (iif) {
2632 struct net_device *dev;
2633
2634 dev = __dev_get_by_index(net, iif);
2635 if (!dev) {
2636 err = -ENODEV;
2637 goto errout_free;
2638 }
2639
2640 skb->protocol = htons(ETH_P_IP);
2641 skb->dev = dev;
2642 skb->mark = mark;
2643 local_bh_disable();
2644 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2645 local_bh_enable();
2646
2647 rt = skb_rtable(skb);
2648 if (err == 0 && rt->dst.error)
2649 err = -rt->dst.error;
2650 } else {
2651 rt = ip_route_output_key(net, &fl4);
2652
2653 err = 0;
2654 if (IS_ERR(rt))
2655 err = PTR_ERR(rt);
2656 }
2657
2658 if (err)
2659 goto errout_free;
2660
2661 skb_dst_set(skb, &rt->dst);
2662 if (rtm->rtm_flags & RTM_F_NOTIFY)
2663 rt->rt_flags |= RTCF_NOTIFY;
2664
2665 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2666 table_id = rt->rt_table_id;
2667
2668 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2669 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2670 RTM_NEWROUTE, 0, 0);
2671 if (err < 0)
2672 goto errout_free;
2673
2674 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2675errout:
2676 return err;
2677
2678errout_free:
2679 kfree_skb(skb);
2680 goto errout;
2681}
2682
2683void ip_rt_multicast_event(struct in_device *in_dev)
2684{
2685 rt_cache_flush(dev_net(in_dev->dev));
2686}
2687
2688#ifdef CONFIG_SYSCTL
2689static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2690static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2691static int ip_rt_gc_elasticity __read_mostly = 8;
2692
2693static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2694 void __user *buffer,
2695 size_t *lenp, loff_t *ppos)
2696{
2697 struct net *net = (struct net *)__ctl->extra1;
2698
2699 if (write) {
2700 rt_cache_flush(net);
2701 fnhe_genid_bump(net);
2702 return 0;
2703 }
2704
2705 return -EINVAL;
2706}
2707
2708static struct ctl_table ipv4_route_table[] = {
2709 {
2710 .procname = "gc_thresh",
2711 .data = &ipv4_dst_ops.gc_thresh,
2712 .maxlen = sizeof(int),
2713 .mode = 0644,
2714 .proc_handler = proc_dointvec,
2715 },
2716 {
2717 .procname = "max_size",
2718 .data = &ip_rt_max_size,
2719 .maxlen = sizeof(int),
2720 .mode = 0644,
2721 .proc_handler = proc_dointvec,
2722 },
2723 {
2724 /* Deprecated. Use gc_min_interval_ms */
2725
2726 .procname = "gc_min_interval",
2727 .data = &ip_rt_gc_min_interval,
2728 .maxlen = sizeof(int),
2729 .mode = 0644,
2730 .proc_handler = proc_dointvec_jiffies,
2731 },
2732 {
2733 .procname = "gc_min_interval_ms",
2734 .data = &ip_rt_gc_min_interval,
2735 .maxlen = sizeof(int),
2736 .mode = 0644,
2737 .proc_handler = proc_dointvec_ms_jiffies,
2738 },
2739 {
2740 .procname = "gc_timeout",
2741 .data = &ip_rt_gc_timeout,
2742 .maxlen = sizeof(int),
2743 .mode = 0644,
2744 .proc_handler = proc_dointvec_jiffies,
2745 },
2746 {
2747 .procname = "gc_interval",
2748 .data = &ip_rt_gc_interval,
2749 .maxlen = sizeof(int),
2750 .mode = 0644,
2751 .proc_handler = proc_dointvec_jiffies,
2752 },
2753 {
2754 .procname = "redirect_load",
2755 .data = &ip_rt_redirect_load,
2756 .maxlen = sizeof(int),
2757 .mode = 0644,
2758 .proc_handler = proc_dointvec,
2759 },
2760 {
2761 .procname = "redirect_number",
2762 .data = &ip_rt_redirect_number,
2763 .maxlen = sizeof(int),
2764 .mode = 0644,
2765 .proc_handler = proc_dointvec,
2766 },
2767 {
2768 .procname = "redirect_silence",
2769 .data = &ip_rt_redirect_silence,
2770 .maxlen = sizeof(int),
2771 .mode = 0644,
2772 .proc_handler = proc_dointvec,
2773 },
2774 {
2775 .procname = "error_cost",
2776 .data = &ip_rt_error_cost,
2777 .maxlen = sizeof(int),
2778 .mode = 0644,
2779 .proc_handler = proc_dointvec,
2780 },
2781 {
2782 .procname = "error_burst",
2783 .data = &ip_rt_error_burst,
2784 .maxlen = sizeof(int),
2785 .mode = 0644,
2786 .proc_handler = proc_dointvec,
2787 },
2788 {
2789 .procname = "gc_elasticity",
2790 .data = &ip_rt_gc_elasticity,
2791 .maxlen = sizeof(int),
2792 .mode = 0644,
2793 .proc_handler = proc_dointvec,
2794 },
2795 {
2796 .procname = "mtu_expires",
2797 .data = &ip_rt_mtu_expires,
2798 .maxlen = sizeof(int),
2799 .mode = 0644,
2800 .proc_handler = proc_dointvec_jiffies,
2801 },
2802 {
2803 .procname = "min_pmtu",
2804 .data = &ip_rt_min_pmtu,
2805 .maxlen = sizeof(int),
2806 .mode = 0644,
2807 .proc_handler = proc_dointvec,
2808 },
2809 {
2810 .procname = "min_adv_mss",
2811 .data = &ip_rt_min_advmss,
2812 .maxlen = sizeof(int),
2813 .mode = 0644,
2814 .proc_handler = proc_dointvec,
2815 },
2816 { }
2817};
2818
2819static struct ctl_table ipv4_route_flush_table[] = {
2820 {
2821 .procname = "flush",
2822 .maxlen = sizeof(int),
2823 .mode = 0200,
2824 .proc_handler = ipv4_sysctl_rtcache_flush,
2825 },
2826 { },
2827};
2828
2829static __net_init int sysctl_route_net_init(struct net *net)
2830{
2831 struct ctl_table *tbl;
2832
2833 tbl = ipv4_route_flush_table;
2834 if (!net_eq(net, &init_net)) {
2835 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2836 if (!tbl)
2837 goto err_dup;
2838
2839 /* Don't export sysctls to unprivileged users */
2840 if (net->user_ns != &init_user_ns)
2841 tbl[0].procname = NULL;
2842 }
2843 tbl[0].extra1 = net;
2844
2845 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2846 if (!net->ipv4.route_hdr)
2847 goto err_reg;
2848 return 0;
2849
2850err_reg:
2851 if (tbl != ipv4_route_flush_table)
2852 kfree(tbl);
2853err_dup:
2854 return -ENOMEM;
2855}
2856
2857static __net_exit void sysctl_route_net_exit(struct net *net)
2858{
2859 struct ctl_table *tbl;
2860
2861 tbl = net->ipv4.route_hdr->ctl_table_arg;
2862 unregister_net_sysctl_table(net->ipv4.route_hdr);
2863 BUG_ON(tbl == ipv4_route_flush_table);
2864 kfree(tbl);
2865}
2866
2867static __net_initdata struct pernet_operations sysctl_route_ops = {
2868 .init = sysctl_route_net_init,
2869 .exit = sysctl_route_net_exit,
2870};
2871#endif
2872
2873static __net_init int rt_genid_init(struct net *net)
2874{
2875 atomic_set(&net->ipv4.rt_genid, 0);
2876 atomic_set(&net->fnhe_genid, 0);
2877 get_random_bytes(&net->ipv4.dev_addr_genid,
2878 sizeof(net->ipv4.dev_addr_genid));
2879 return 0;
2880}
2881
2882static __net_initdata struct pernet_operations rt_genid_ops = {
2883 .init = rt_genid_init,
2884};
2885
2886static int __net_init ipv4_inetpeer_init(struct net *net)
2887{
2888 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2889
2890 if (!bp)
2891 return -ENOMEM;
2892 inet_peer_base_init(bp);
2893 net->ipv4.peers = bp;
2894 return 0;
2895}
2896
2897static void __net_exit ipv4_inetpeer_exit(struct net *net)
2898{
2899 struct inet_peer_base *bp = net->ipv4.peers;
2900
2901 net->ipv4.peers = NULL;
2902 inetpeer_invalidate_tree(bp);
2903 kfree(bp);
2904}
2905
2906static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2907 .init = ipv4_inetpeer_init,
2908 .exit = ipv4_inetpeer_exit,
2909};
2910
2911#ifdef CONFIG_IP_ROUTE_CLASSID
2912struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2913#endif /* CONFIG_IP_ROUTE_CLASSID */
2914
2915int __init ip_rt_init(void)
2916{
2917 int rc = 0;
2918 int cpu;
2919
2920 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2921 if (!ip_idents)
2922 panic("IP: failed to allocate ip_idents\n");
2923
2924 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2925
2926 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2927 if (!ip_tstamps)
2928 panic("IP: failed to allocate ip_tstamps\n");
2929
2930 for_each_possible_cpu(cpu) {
2931 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2932
2933 INIT_LIST_HEAD(&ul->head);
2934 spin_lock_init(&ul->lock);
2935 }
2936#ifdef CONFIG_IP_ROUTE_CLASSID
2937 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2938 if (!ip_rt_acct)
2939 panic("IP: failed to allocate ip_rt_acct\n");
2940#endif
2941
2942 ipv4_dst_ops.kmem_cachep =
2943 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2944 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2945
2946 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2947
2948 if (dst_entries_init(&ipv4_dst_ops) < 0)
2949 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2950
2951 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2952 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2953
2954 ipv4_dst_ops.gc_thresh = ~0;
2955 ip_rt_max_size = INT_MAX;
2956
2957 devinet_init();
2958 ip_fib_init();
2959
2960 if (ip_rt_proc_init())
2961 pr_err("Unable to create route proc files\n");
2962#ifdef CONFIG_XFRM
2963 xfrm_init();
2964 xfrm4_init();
2965#endif
2966 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2967
2968#ifdef CONFIG_SYSCTL
2969 register_pernet_subsys(&sysctl_route_ops);
2970#endif
2971 register_pernet_subsys(&rt_genid_ops);
2972 register_pernet_subsys(&ipv4_inetpeer_ops);
2973 return rc;
2974}
2975
2976#ifdef CONFIG_SYSCTL
2977/*
2978 * We really need to sanitize the damn ipv4 init order, then all
2979 * this nonsense will go away.
2980 */
2981void __init ip_static_sysctl_init(void)
2982{
2983 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2984}
2985#endif