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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/uaccess.h>
65#include <linux/bitops.h>
66#include <linux/types.h>
67#include <linux/kernel.h>
68#include <linux/mm.h>
69#include <linux/string.h>
70#include <linux/socket.h>
71#include <linux/sockios.h>
72#include <linux/errno.h>
73#include <linux/in.h>
74#include <linux/inet.h>
75#include <linux/netdevice.h>
76#include <linux/proc_fs.h>
77#include <linux/init.h>
78#include <linux/skbuff.h>
79#include <linux/inetdevice.h>
80#include <linux/igmp.h>
81#include <linux/pkt_sched.h>
82#include <linux/mroute.h>
83#include <linux/netfilter_ipv4.h>
84#include <linux/random.h>
85#include <linux/rcupdate.h>
86#include <linux/times.h>
87#include <linux/slab.h>
88#include <linux/jhash.h>
89#include <net/dst.h>
90#include <net/dst_metadata.h>
91#include <net/net_namespace.h>
92#include <net/protocol.h>
93#include <net/ip.h>
94#include <net/route.h>
95#include <net/inetpeer.h>
96#include <net/sock.h>
97#include <net/ip_fib.h>
98#include <net/nexthop.h>
99#include <net/arp.h>
100#include <net/tcp.h>
101#include <net/icmp.h>
102#include <net/xfrm.h>
103#include <net/lwtunnel.h>
104#include <net/netevent.h>
105#include <net/rtnetlink.h>
106#ifdef CONFIG_SYSCTL
107#include <linux/sysctl.h>
108#endif
109#include <net/secure_seq.h>
110#include <net/ip_tunnels.h>
111#include <net/l3mdev.h>
112
113#include "fib_lookup.h"
114
115#define RT_FL_TOS(oldflp4) \
116 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
117
118#define RT_GC_TIMEOUT (300*HZ)
119
120static int ip_rt_max_size;
121static int ip_rt_redirect_number __read_mostly = 9;
122static int ip_rt_redirect_load __read_mostly = HZ / 50;
123static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
124static int ip_rt_error_cost __read_mostly = HZ;
125static int ip_rt_error_burst __read_mostly = 5 * HZ;
126static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
127static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
128static int ip_rt_min_advmss __read_mostly = 256;
129
130static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
131
132/*
133 * Interface to generic destination cache.
134 */
135
136static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
137static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
138static unsigned int ipv4_mtu(const struct dst_entry *dst);
139static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
140static void ipv4_link_failure(struct sk_buff *skb);
141static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
142 struct sk_buff *skb, u32 mtu);
143static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
144 struct sk_buff *skb);
145static void ipv4_dst_destroy(struct dst_entry *dst);
146
147static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
148{
149 WARN_ON(1);
150 return NULL;
151}
152
153static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
154 struct sk_buff *skb,
155 const void *daddr);
156static void ipv4_confirm_neigh(const struct dst_entry *dst, 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 .confirm_neigh = ipv4_confirm_neigh,
172};
173
174#define ECN_OR_COST(class) TC_PRIO_##class
175
176const __u8 ip_tos2prio[16] = {
177 TC_PRIO_BESTEFFORT,
178 ECN_OR_COST(BESTEFFORT),
179 TC_PRIO_BESTEFFORT,
180 ECN_OR_COST(BESTEFFORT),
181 TC_PRIO_BULK,
182 ECN_OR_COST(BULK),
183 TC_PRIO_BULK,
184 ECN_OR_COST(BULK),
185 TC_PRIO_INTERACTIVE,
186 ECN_OR_COST(INTERACTIVE),
187 TC_PRIO_INTERACTIVE,
188 ECN_OR_COST(INTERACTIVE),
189 TC_PRIO_INTERACTIVE_BULK,
190 ECN_OR_COST(INTERACTIVE_BULK),
191 TC_PRIO_INTERACTIVE_BULK,
192 ECN_OR_COST(INTERACTIVE_BULK)
193};
194EXPORT_SYMBOL(ip_tos2prio);
195
196static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
197#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
198
199#ifdef CONFIG_PROC_FS
200static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
201{
202 if (*pos)
203 return NULL;
204 return SEQ_START_TOKEN;
205}
206
207static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
208{
209 ++*pos;
210 return NULL;
211}
212
213static void rt_cache_seq_stop(struct seq_file *seq, void *v)
214{
215}
216
217static int rt_cache_seq_show(struct seq_file *seq, void *v)
218{
219 if (v == SEQ_START_TOKEN)
220 seq_printf(seq, "%-127s\n",
221 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
222 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
223 "HHUptod\tSpecDst");
224 return 0;
225}
226
227static const struct seq_operations rt_cache_seq_ops = {
228 .start = rt_cache_seq_start,
229 .next = rt_cache_seq_next,
230 .stop = rt_cache_seq_stop,
231 .show = rt_cache_seq_show,
232};
233
234static int rt_cache_seq_open(struct inode *inode, struct file *file)
235{
236 return seq_open(file, &rt_cache_seq_ops);
237}
238
239static const struct file_operations rt_cache_seq_fops = {
240 .open = rt_cache_seq_open,
241 .read = seq_read,
242 .llseek = seq_lseek,
243 .release = seq_release,
244};
245
246
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 .open = rt_cpu_seq_open,
331 .read = seq_read,
332 .llseek = seq_lseek,
333 .release = seq_release,
334};
335
336#ifdef CONFIG_IP_ROUTE_CLASSID
337static int rt_acct_proc_show(struct seq_file *m, void *v)
338{
339 struct ip_rt_acct *dst, *src;
340 unsigned int i, j;
341
342 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
343 if (!dst)
344 return -ENOMEM;
345
346 for_each_possible_cpu(i) {
347 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
348 for (j = 0; j < 256; j++) {
349 dst[j].o_bytes += src[j].o_bytes;
350 dst[j].o_packets += src[j].o_packets;
351 dst[j].i_bytes += src[j].i_bytes;
352 dst[j].i_packets += src[j].i_packets;
353 }
354 }
355
356 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
357 kfree(dst);
358 return 0;
359}
360#endif
361
362static int __net_init ip_rt_do_proc_init(struct net *net)
363{
364 struct proc_dir_entry *pde;
365
366 pde = proc_create("rt_cache", 0444, net->proc_net,
367 &rt_cache_seq_fops);
368 if (!pde)
369 goto err1;
370
371 pde = proc_create("rt_cache", 0444,
372 net->proc_net_stat, &rt_cpu_seq_fops);
373 if (!pde)
374 goto err2;
375
376#ifdef CONFIG_IP_ROUTE_CLASSID
377 pde = proc_create_single("rt_acct", 0, net->proc_net,
378 rt_acct_proc_show);
379 if (!pde)
380 goto err3;
381#endif
382 return 0;
383
384#ifdef CONFIG_IP_ROUTE_CLASSID
385err3:
386 remove_proc_entry("rt_cache", net->proc_net_stat);
387#endif
388err2:
389 remove_proc_entry("rt_cache", net->proc_net);
390err1:
391 return -ENOMEM;
392}
393
394static void __net_exit ip_rt_do_proc_exit(struct net *net)
395{
396 remove_proc_entry("rt_cache", net->proc_net_stat);
397 remove_proc_entry("rt_cache", net->proc_net);
398#ifdef CONFIG_IP_ROUTE_CLASSID
399 remove_proc_entry("rt_acct", net->proc_net);
400#endif
401}
402
403static struct pernet_operations ip_rt_proc_ops __net_initdata = {
404 .init = ip_rt_do_proc_init,
405 .exit = ip_rt_do_proc_exit,
406};
407
408static int __init ip_rt_proc_init(void)
409{
410 return register_pernet_subsys(&ip_rt_proc_ops);
411}
412
413#else
414static inline int ip_rt_proc_init(void)
415{
416 return 0;
417}
418#endif /* CONFIG_PROC_FS */
419
420static inline bool rt_is_expired(const struct rtable *rth)
421{
422 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
423}
424
425void rt_cache_flush(struct net *net)
426{
427 rt_genid_bump_ipv4(net);
428}
429
430static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
431 struct sk_buff *skb,
432 const void *daddr)
433{
434 const struct rtable *rt = container_of(dst, struct rtable, dst);
435 struct net_device *dev = dst->dev;
436 struct neighbour *n;
437
438 rcu_read_lock_bh();
439
440 if (likely(rt->rt_gw_family == AF_INET)) {
441 n = ip_neigh_gw4(dev, rt->rt_gw4);
442 } else if (rt->rt_gw_family == AF_INET6) {
443 n = ip_neigh_gw6(dev, &rt->rt_gw6);
444 } else {
445 __be32 pkey;
446
447 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
448 n = ip_neigh_gw4(dev, pkey);
449 }
450
451 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
452 n = NULL;
453
454 rcu_read_unlock_bh();
455
456 return n;
457}
458
459static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
460{
461 const struct rtable *rt = container_of(dst, struct rtable, dst);
462 struct net_device *dev = dst->dev;
463 const __be32 *pkey = daddr;
464
465 if (rt->rt_gw_family == AF_INET) {
466 pkey = (const __be32 *)&rt->rt_gw4;
467 } else if (rt->rt_gw_family == AF_INET6) {
468 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
469 } else if (!daddr ||
470 (rt->rt_flags &
471 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
472 return;
473 }
474 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
475}
476
477#define IP_IDENTS_SZ 2048u
478
479static atomic_t *ip_idents __read_mostly;
480static u32 *ip_tstamps __read_mostly;
481
482/* In order to protect privacy, we add a perturbation to identifiers
483 * if one generator is seldom used. This makes hard for an attacker
484 * to infer how many packets were sent between two points in time.
485 */
486u32 ip_idents_reserve(u32 hash, int segs)
487{
488 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
489 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
490 u32 old = READ_ONCE(*p_tstamp);
491 u32 now = (u32)jiffies;
492 u32 new, delta = 0;
493
494 if (old != now && cmpxchg(p_tstamp, old, now) == old)
495 delta = prandom_u32_max(now - old);
496
497 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
498 do {
499 old = (u32)atomic_read(p_id);
500 new = old + delta + segs;
501 } while (atomic_cmpxchg(p_id, old, new) != old);
502
503 return new - segs;
504}
505EXPORT_SYMBOL(ip_idents_reserve);
506
507void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
508{
509 u32 hash, id;
510
511 /* Note the following code is not safe, but this is okay. */
512 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
513 get_random_bytes(&net->ipv4.ip_id_key,
514 sizeof(net->ipv4.ip_id_key));
515
516 hash = siphash_3u32((__force u32)iph->daddr,
517 (__force u32)iph->saddr,
518 iph->protocol,
519 &net->ipv4.ip_id_key);
520 id = ip_idents_reserve(hash, segs);
521 iph->id = htons(id);
522}
523EXPORT_SYMBOL(__ip_select_ident);
524
525static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
526 const struct sock *sk,
527 const struct iphdr *iph,
528 int oif, u8 tos,
529 u8 prot, u32 mark, int flow_flags)
530{
531 if (sk) {
532 const struct inet_sock *inet = inet_sk(sk);
533
534 oif = sk->sk_bound_dev_if;
535 mark = sk->sk_mark;
536 tos = RT_CONN_FLAGS(sk);
537 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
538 }
539 flowi4_init_output(fl4, oif, mark, tos,
540 RT_SCOPE_UNIVERSE, prot,
541 flow_flags,
542 iph->daddr, iph->saddr, 0, 0,
543 sock_net_uid(net, sk));
544}
545
546static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
547 const struct sock *sk)
548{
549 const struct net *net = dev_net(skb->dev);
550 const struct iphdr *iph = ip_hdr(skb);
551 int oif = skb->dev->ifindex;
552 u8 tos = RT_TOS(iph->tos);
553 u8 prot = iph->protocol;
554 u32 mark = skb->mark;
555
556 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
557}
558
559static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
560{
561 const struct inet_sock *inet = inet_sk(sk);
562 const struct ip_options_rcu *inet_opt;
563 __be32 daddr = inet->inet_daddr;
564
565 rcu_read_lock();
566 inet_opt = rcu_dereference(inet->inet_opt);
567 if (inet_opt && inet_opt->opt.srr)
568 daddr = inet_opt->opt.faddr;
569 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
570 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
571 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
572 inet_sk_flowi_flags(sk),
573 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
574 rcu_read_unlock();
575}
576
577static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
578 const struct sk_buff *skb)
579{
580 if (skb)
581 build_skb_flow_key(fl4, skb, sk);
582 else
583 build_sk_flow_key(fl4, sk);
584}
585
586static DEFINE_SPINLOCK(fnhe_lock);
587
588static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
589{
590 struct rtable *rt;
591
592 rt = rcu_dereference(fnhe->fnhe_rth_input);
593 if (rt) {
594 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
595 dst_dev_put(&rt->dst);
596 dst_release(&rt->dst);
597 }
598 rt = rcu_dereference(fnhe->fnhe_rth_output);
599 if (rt) {
600 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
601 dst_dev_put(&rt->dst);
602 dst_release(&rt->dst);
603 }
604}
605
606static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
607{
608 struct fib_nh_exception *fnhe, *oldest;
609
610 oldest = rcu_dereference(hash->chain);
611 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
612 fnhe = rcu_dereference(fnhe->fnhe_next)) {
613 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
614 oldest = fnhe;
615 }
616 fnhe_flush_routes(oldest);
617 return oldest;
618}
619
620static inline u32 fnhe_hashfun(__be32 daddr)
621{
622 static u32 fnhe_hashrnd __read_mostly;
623 u32 hval;
624
625 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
626 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
627 return hash_32(hval, FNHE_HASH_SHIFT);
628}
629
630static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
631{
632 rt->rt_pmtu = fnhe->fnhe_pmtu;
633 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
634 rt->dst.expires = fnhe->fnhe_expires;
635
636 if (fnhe->fnhe_gw) {
637 rt->rt_flags |= RTCF_REDIRECTED;
638 rt->rt_uses_gateway = 1;
639 rt->rt_gw_family = AF_INET;
640 rt->rt_gw4 = fnhe->fnhe_gw;
641 }
642}
643
644static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
645 __be32 gw, u32 pmtu, bool lock,
646 unsigned long expires)
647{
648 struct fnhe_hash_bucket *hash;
649 struct fib_nh_exception *fnhe;
650 struct rtable *rt;
651 u32 genid, hval;
652 unsigned int i;
653 int depth;
654
655 genid = fnhe_genid(dev_net(nhc->nhc_dev));
656 hval = fnhe_hashfun(daddr);
657
658 spin_lock_bh(&fnhe_lock);
659
660 hash = rcu_dereference(nhc->nhc_exceptions);
661 if (!hash) {
662 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
663 if (!hash)
664 goto out_unlock;
665 rcu_assign_pointer(nhc->nhc_exceptions, hash);
666 }
667
668 hash += hval;
669
670 depth = 0;
671 for (fnhe = rcu_dereference(hash->chain); fnhe;
672 fnhe = rcu_dereference(fnhe->fnhe_next)) {
673 if (fnhe->fnhe_daddr == daddr)
674 break;
675 depth++;
676 }
677
678 if (fnhe) {
679 if (fnhe->fnhe_genid != genid)
680 fnhe->fnhe_genid = genid;
681 if (gw)
682 fnhe->fnhe_gw = gw;
683 if (pmtu) {
684 fnhe->fnhe_pmtu = pmtu;
685 fnhe->fnhe_mtu_locked = lock;
686 }
687 fnhe->fnhe_expires = max(1UL, expires);
688 /* Update all cached dsts too */
689 rt = rcu_dereference(fnhe->fnhe_rth_input);
690 if (rt)
691 fill_route_from_fnhe(rt, fnhe);
692 rt = rcu_dereference(fnhe->fnhe_rth_output);
693 if (rt)
694 fill_route_from_fnhe(rt, fnhe);
695 } else {
696 if (depth > FNHE_RECLAIM_DEPTH)
697 fnhe = fnhe_oldest(hash);
698 else {
699 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
700 if (!fnhe)
701 goto out_unlock;
702
703 fnhe->fnhe_next = hash->chain;
704 rcu_assign_pointer(hash->chain, fnhe);
705 }
706 fnhe->fnhe_genid = genid;
707 fnhe->fnhe_daddr = daddr;
708 fnhe->fnhe_gw = gw;
709 fnhe->fnhe_pmtu = pmtu;
710 fnhe->fnhe_mtu_locked = lock;
711 fnhe->fnhe_expires = max(1UL, expires);
712
713 /* Exception created; mark the cached routes for the nexthop
714 * stale, so anyone caching it rechecks if this exception
715 * applies to them.
716 */
717 rt = rcu_dereference(nhc->nhc_rth_input);
718 if (rt)
719 rt->dst.obsolete = DST_OBSOLETE_KILL;
720
721 for_each_possible_cpu(i) {
722 struct rtable __rcu **prt;
723 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
724 rt = rcu_dereference(*prt);
725 if (rt)
726 rt->dst.obsolete = DST_OBSOLETE_KILL;
727 }
728 }
729
730 fnhe->fnhe_stamp = jiffies;
731
732out_unlock:
733 spin_unlock_bh(&fnhe_lock);
734}
735
736static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
737 bool kill_route)
738{
739 __be32 new_gw = icmp_hdr(skb)->un.gateway;
740 __be32 old_gw = ip_hdr(skb)->saddr;
741 struct net_device *dev = skb->dev;
742 struct in_device *in_dev;
743 struct fib_result res;
744 struct neighbour *n;
745 struct net *net;
746
747 switch (icmp_hdr(skb)->code & 7) {
748 case ICMP_REDIR_NET:
749 case ICMP_REDIR_NETTOS:
750 case ICMP_REDIR_HOST:
751 case ICMP_REDIR_HOSTTOS:
752 break;
753
754 default:
755 return;
756 }
757
758 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
759 return;
760
761 in_dev = __in_dev_get_rcu(dev);
762 if (!in_dev)
763 return;
764
765 net = dev_net(dev);
766 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
767 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
768 ipv4_is_zeronet(new_gw))
769 goto reject_redirect;
770
771 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
772 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
773 goto reject_redirect;
774 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
775 goto reject_redirect;
776 } else {
777 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
778 goto reject_redirect;
779 }
780
781 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
782 if (!n)
783 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
784 if (!IS_ERR(n)) {
785 if (!(n->nud_state & NUD_VALID)) {
786 neigh_event_send(n, NULL);
787 } else {
788 if (fib_lookup(net, fl4, &res, 0) == 0) {
789 struct fib_nh_common *nhc = FIB_RES_NHC(res);
790
791 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
792 0, false,
793 jiffies + ip_rt_gc_timeout);
794 }
795 if (kill_route)
796 rt->dst.obsolete = DST_OBSOLETE_KILL;
797 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
798 }
799 neigh_release(n);
800 }
801 return;
802
803reject_redirect:
804#ifdef CONFIG_IP_ROUTE_VERBOSE
805 if (IN_DEV_LOG_MARTIANS(in_dev)) {
806 const struct iphdr *iph = (const struct iphdr *) skb->data;
807 __be32 daddr = iph->daddr;
808 __be32 saddr = iph->saddr;
809
810 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
811 " Advised path = %pI4 -> %pI4\n",
812 &old_gw, dev->name, &new_gw,
813 &saddr, &daddr);
814 }
815#endif
816 ;
817}
818
819static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
820{
821 struct rtable *rt;
822 struct flowi4 fl4;
823 const struct iphdr *iph = (const struct iphdr *) skb->data;
824 struct net *net = dev_net(skb->dev);
825 int oif = skb->dev->ifindex;
826 u8 tos = RT_TOS(iph->tos);
827 u8 prot = iph->protocol;
828 u32 mark = skb->mark;
829
830 rt = (struct rtable *) dst;
831
832 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
833 __ip_do_redirect(rt, skb, &fl4, true);
834}
835
836static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
837{
838 struct rtable *rt = (struct rtable *)dst;
839 struct dst_entry *ret = dst;
840
841 if (rt) {
842 if (dst->obsolete > 0) {
843 ip_rt_put(rt);
844 ret = NULL;
845 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
846 rt->dst.expires) {
847 ip_rt_put(rt);
848 ret = NULL;
849 }
850 }
851 return ret;
852}
853
854/*
855 * Algorithm:
856 * 1. The first ip_rt_redirect_number redirects are sent
857 * with exponential backoff, then we stop sending them at all,
858 * assuming that the host ignores our redirects.
859 * 2. If we did not see packets requiring redirects
860 * during ip_rt_redirect_silence, we assume that the host
861 * forgot redirected route and start to send redirects again.
862 *
863 * This algorithm is much cheaper and more intelligent than dumb load limiting
864 * in icmp.c.
865 *
866 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
867 * and "frag. need" (breaks PMTU discovery) in icmp.c.
868 */
869
870void ip_rt_send_redirect(struct sk_buff *skb)
871{
872 struct rtable *rt = skb_rtable(skb);
873 struct in_device *in_dev;
874 struct inet_peer *peer;
875 struct net *net;
876 int log_martians;
877 int vif;
878
879 rcu_read_lock();
880 in_dev = __in_dev_get_rcu(rt->dst.dev);
881 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
882 rcu_read_unlock();
883 return;
884 }
885 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
886 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
887 rcu_read_unlock();
888
889 net = dev_net(rt->dst.dev);
890 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
891 if (!peer) {
892 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
893 rt_nexthop(rt, ip_hdr(skb)->daddr));
894 return;
895 }
896
897 /* No redirected packets during ip_rt_redirect_silence;
898 * reset the algorithm.
899 */
900 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
901 peer->rate_tokens = 0;
902 peer->n_redirects = 0;
903 }
904
905 /* Too many ignored redirects; do not send anything
906 * set dst.rate_last to the last seen redirected packet.
907 */
908 if (peer->n_redirects >= ip_rt_redirect_number) {
909 peer->rate_last = jiffies;
910 goto out_put_peer;
911 }
912
913 /* Check for load limit; set rate_last to the latest sent
914 * redirect.
915 */
916 if (peer->rate_tokens == 0 ||
917 time_after(jiffies,
918 (peer->rate_last +
919 (ip_rt_redirect_load << peer->n_redirects)))) {
920 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
921
922 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
923 peer->rate_last = jiffies;
924 ++peer->n_redirects;
925#ifdef CONFIG_IP_ROUTE_VERBOSE
926 if (log_martians &&
927 peer->n_redirects == ip_rt_redirect_number)
928 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
929 &ip_hdr(skb)->saddr, inet_iif(skb),
930 &ip_hdr(skb)->daddr, &gw);
931#endif
932 }
933out_put_peer:
934 inet_putpeer(peer);
935}
936
937static int ip_error(struct sk_buff *skb)
938{
939 struct rtable *rt = skb_rtable(skb);
940 struct net_device *dev = skb->dev;
941 struct in_device *in_dev;
942 struct inet_peer *peer;
943 unsigned long now;
944 struct net *net;
945 bool send;
946 int code;
947
948 if (netif_is_l3_master(skb->dev)) {
949 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
950 if (!dev)
951 goto out;
952 }
953
954 in_dev = __in_dev_get_rcu(dev);
955
956 /* IP on this device is disabled. */
957 if (!in_dev)
958 goto out;
959
960 net = dev_net(rt->dst.dev);
961 if (!IN_DEV_FORWARD(in_dev)) {
962 switch (rt->dst.error) {
963 case EHOSTUNREACH:
964 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
965 break;
966
967 case ENETUNREACH:
968 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
969 break;
970 }
971 goto out;
972 }
973
974 switch (rt->dst.error) {
975 case EINVAL:
976 default:
977 goto out;
978 case EHOSTUNREACH:
979 code = ICMP_HOST_UNREACH;
980 break;
981 case ENETUNREACH:
982 code = ICMP_NET_UNREACH;
983 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
984 break;
985 case EACCES:
986 code = ICMP_PKT_FILTERED;
987 break;
988 }
989
990 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
991 l3mdev_master_ifindex(skb->dev), 1);
992
993 send = true;
994 if (peer) {
995 now = jiffies;
996 peer->rate_tokens += now - peer->rate_last;
997 if (peer->rate_tokens > ip_rt_error_burst)
998 peer->rate_tokens = ip_rt_error_burst;
999 peer->rate_last = now;
1000 if (peer->rate_tokens >= ip_rt_error_cost)
1001 peer->rate_tokens -= ip_rt_error_cost;
1002 else
1003 send = false;
1004 inet_putpeer(peer);
1005 }
1006 if (send)
1007 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1008
1009out: kfree_skb(skb);
1010 return 0;
1011}
1012
1013static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1014{
1015 struct dst_entry *dst = &rt->dst;
1016 u32 old_mtu = ipv4_mtu(dst);
1017 struct fib_result res;
1018 bool lock = false;
1019
1020 if (ip_mtu_locked(dst))
1021 return;
1022
1023 if (old_mtu < mtu)
1024 return;
1025
1026 if (mtu < ip_rt_min_pmtu) {
1027 lock = true;
1028 mtu = min(old_mtu, ip_rt_min_pmtu);
1029 }
1030
1031 if (rt->rt_pmtu == mtu && !lock &&
1032 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1033 return;
1034
1035 rcu_read_lock();
1036 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1037 struct fib_nh_common *nhc = FIB_RES_NHC(res);
1038
1039 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1040 jiffies + ip_rt_mtu_expires);
1041 }
1042 rcu_read_unlock();
1043}
1044
1045static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1046 struct sk_buff *skb, u32 mtu)
1047{
1048 struct rtable *rt = (struct rtable *) dst;
1049 struct flowi4 fl4;
1050
1051 ip_rt_build_flow_key(&fl4, sk, skb);
1052 __ip_rt_update_pmtu(rt, &fl4, mtu);
1053}
1054
1055void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1056 int oif, u8 protocol)
1057{
1058 const struct iphdr *iph = (const struct iphdr *) skb->data;
1059 struct flowi4 fl4;
1060 struct rtable *rt;
1061 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1062
1063 __build_flow_key(net, &fl4, NULL, iph, oif,
1064 RT_TOS(iph->tos), protocol, mark, 0);
1065 rt = __ip_route_output_key(net, &fl4);
1066 if (!IS_ERR(rt)) {
1067 __ip_rt_update_pmtu(rt, &fl4, mtu);
1068 ip_rt_put(rt);
1069 }
1070}
1071EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1072
1073static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1074{
1075 const struct iphdr *iph = (const struct iphdr *) skb->data;
1076 struct flowi4 fl4;
1077 struct rtable *rt;
1078
1079 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1080
1081 if (!fl4.flowi4_mark)
1082 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1083
1084 rt = __ip_route_output_key(sock_net(sk), &fl4);
1085 if (!IS_ERR(rt)) {
1086 __ip_rt_update_pmtu(rt, &fl4, mtu);
1087 ip_rt_put(rt);
1088 }
1089}
1090
1091void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1092{
1093 const struct iphdr *iph = (const struct iphdr *) skb->data;
1094 struct flowi4 fl4;
1095 struct rtable *rt;
1096 struct dst_entry *odst = NULL;
1097 bool new = false;
1098 struct net *net = sock_net(sk);
1099
1100 bh_lock_sock(sk);
1101
1102 if (!ip_sk_accept_pmtu(sk))
1103 goto out;
1104
1105 odst = sk_dst_get(sk);
1106
1107 if (sock_owned_by_user(sk) || !odst) {
1108 __ipv4_sk_update_pmtu(skb, sk, mtu);
1109 goto out;
1110 }
1111
1112 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1113
1114 rt = (struct rtable *)odst;
1115 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1116 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1117 if (IS_ERR(rt))
1118 goto out;
1119
1120 new = true;
1121 }
1122
1123 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1124
1125 if (!dst_check(&rt->dst, 0)) {
1126 if (new)
1127 dst_release(&rt->dst);
1128
1129 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1130 if (IS_ERR(rt))
1131 goto out;
1132
1133 new = true;
1134 }
1135
1136 if (new)
1137 sk_dst_set(sk, &rt->dst);
1138
1139out:
1140 bh_unlock_sock(sk);
1141 dst_release(odst);
1142}
1143EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1144
1145void ipv4_redirect(struct sk_buff *skb, struct net *net,
1146 int oif, u8 protocol)
1147{
1148 const struct iphdr *iph = (const struct iphdr *) skb->data;
1149 struct flowi4 fl4;
1150 struct rtable *rt;
1151
1152 __build_flow_key(net, &fl4, NULL, iph, oif,
1153 RT_TOS(iph->tos), protocol, 0, 0);
1154 rt = __ip_route_output_key(net, &fl4);
1155 if (!IS_ERR(rt)) {
1156 __ip_do_redirect(rt, skb, &fl4, false);
1157 ip_rt_put(rt);
1158 }
1159}
1160EXPORT_SYMBOL_GPL(ipv4_redirect);
1161
1162void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1163{
1164 const struct iphdr *iph = (const struct iphdr *) skb->data;
1165 struct flowi4 fl4;
1166 struct rtable *rt;
1167 struct net *net = sock_net(sk);
1168
1169 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1170 rt = __ip_route_output_key(net, &fl4);
1171 if (!IS_ERR(rt)) {
1172 __ip_do_redirect(rt, skb, &fl4, false);
1173 ip_rt_put(rt);
1174 }
1175}
1176EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1177
1178static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1179{
1180 struct rtable *rt = (struct rtable *) dst;
1181
1182 /* All IPV4 dsts are created with ->obsolete set to the value
1183 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1184 * into this function always.
1185 *
1186 * When a PMTU/redirect information update invalidates a route,
1187 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1188 * DST_OBSOLETE_DEAD.
1189 */
1190 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1191 return NULL;
1192 return dst;
1193}
1194
1195static void ipv4_send_dest_unreach(struct sk_buff *skb)
1196{
1197 struct ip_options opt;
1198 int res;
1199
1200 /* Recompile ip options since IPCB may not be valid anymore.
1201 * Also check we have a reasonable ipv4 header.
1202 */
1203 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1204 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1205 return;
1206
1207 memset(&opt, 0, sizeof(opt));
1208 if (ip_hdr(skb)->ihl > 5) {
1209 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1210 return;
1211 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1212
1213 rcu_read_lock();
1214 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL);
1215 rcu_read_unlock();
1216
1217 if (res)
1218 return;
1219 }
1220 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1221}
1222
1223static void ipv4_link_failure(struct sk_buff *skb)
1224{
1225 struct rtable *rt;
1226
1227 ipv4_send_dest_unreach(skb);
1228
1229 rt = skb_rtable(skb);
1230 if (rt)
1231 dst_set_expires(&rt->dst, 0);
1232}
1233
1234static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1235{
1236 pr_debug("%s: %pI4 -> %pI4, %s\n",
1237 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1238 skb->dev ? skb->dev->name : "?");
1239 kfree_skb(skb);
1240 WARN_ON(1);
1241 return 0;
1242}
1243
1244/*
1245 We do not cache source address of outgoing interface,
1246 because it is used only by IP RR, TS and SRR options,
1247 so that it out of fast path.
1248
1249 BTW remember: "addr" is allowed to be not aligned
1250 in IP options!
1251 */
1252
1253void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1254{
1255 __be32 src;
1256
1257 if (rt_is_output_route(rt))
1258 src = ip_hdr(skb)->saddr;
1259 else {
1260 struct fib_result res;
1261 struct iphdr *iph = ip_hdr(skb);
1262 struct flowi4 fl4 = {
1263 .daddr = iph->daddr,
1264 .saddr = iph->saddr,
1265 .flowi4_tos = RT_TOS(iph->tos),
1266 .flowi4_oif = rt->dst.dev->ifindex,
1267 .flowi4_iif = skb->dev->ifindex,
1268 .flowi4_mark = skb->mark,
1269 };
1270
1271 rcu_read_lock();
1272 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1273 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1274 else
1275 src = inet_select_addr(rt->dst.dev,
1276 rt_nexthop(rt, iph->daddr),
1277 RT_SCOPE_UNIVERSE);
1278 rcu_read_unlock();
1279 }
1280 memcpy(addr, &src, 4);
1281}
1282
1283#ifdef CONFIG_IP_ROUTE_CLASSID
1284static void set_class_tag(struct rtable *rt, u32 tag)
1285{
1286 if (!(rt->dst.tclassid & 0xFFFF))
1287 rt->dst.tclassid |= tag & 0xFFFF;
1288 if (!(rt->dst.tclassid & 0xFFFF0000))
1289 rt->dst.tclassid |= tag & 0xFFFF0000;
1290}
1291#endif
1292
1293static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1294{
1295 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1296 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1297 ip_rt_min_advmss);
1298
1299 return min(advmss, IPV4_MAX_PMTU - header_size);
1300}
1301
1302static unsigned int ipv4_mtu(const struct dst_entry *dst)
1303{
1304 const struct rtable *rt = (const struct rtable *) dst;
1305 unsigned int mtu = rt->rt_pmtu;
1306
1307 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1308 mtu = dst_metric_raw(dst, RTAX_MTU);
1309
1310 if (mtu)
1311 return mtu;
1312
1313 mtu = READ_ONCE(dst->dev->mtu);
1314
1315 if (unlikely(ip_mtu_locked(dst))) {
1316 if (rt->rt_uses_gateway && mtu > 576)
1317 mtu = 576;
1318 }
1319
1320 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1321
1322 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1323}
1324
1325static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1326{
1327 struct fnhe_hash_bucket *hash;
1328 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1329 u32 hval = fnhe_hashfun(daddr);
1330
1331 spin_lock_bh(&fnhe_lock);
1332
1333 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1334 lockdep_is_held(&fnhe_lock));
1335 hash += hval;
1336
1337 fnhe_p = &hash->chain;
1338 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1339 while (fnhe) {
1340 if (fnhe->fnhe_daddr == daddr) {
1341 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1342 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1343 /* set fnhe_daddr to 0 to ensure it won't bind with
1344 * new dsts in rt_bind_exception().
1345 */
1346 fnhe->fnhe_daddr = 0;
1347 fnhe_flush_routes(fnhe);
1348 kfree_rcu(fnhe, rcu);
1349 break;
1350 }
1351 fnhe_p = &fnhe->fnhe_next;
1352 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1353 lockdep_is_held(&fnhe_lock));
1354 }
1355
1356 spin_unlock_bh(&fnhe_lock);
1357}
1358
1359static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1360 __be32 daddr)
1361{
1362 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1363 struct fib_nh_exception *fnhe;
1364 u32 hval;
1365
1366 if (!hash)
1367 return NULL;
1368
1369 hval = fnhe_hashfun(daddr);
1370
1371 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1372 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1373 if (fnhe->fnhe_daddr == daddr) {
1374 if (fnhe->fnhe_expires &&
1375 time_after(jiffies, fnhe->fnhe_expires)) {
1376 ip_del_fnhe(nhc, daddr);
1377 break;
1378 }
1379 return fnhe;
1380 }
1381 }
1382 return NULL;
1383}
1384
1385/* MTU selection:
1386 * 1. mtu on route is locked - use it
1387 * 2. mtu from nexthop exception
1388 * 3. mtu from egress device
1389 */
1390
1391u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1392{
1393 struct fib_nh_common *nhc = res->nhc;
1394 struct net_device *dev = nhc->nhc_dev;
1395 struct fib_info *fi = res->fi;
1396 u32 mtu = 0;
1397
1398 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1399 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1400 mtu = fi->fib_mtu;
1401
1402 if (likely(!mtu)) {
1403 struct fib_nh_exception *fnhe;
1404
1405 fnhe = find_exception(nhc, daddr);
1406 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1407 mtu = fnhe->fnhe_pmtu;
1408 }
1409
1410 if (likely(!mtu))
1411 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1412
1413 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1414}
1415
1416static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1417 __be32 daddr, const bool do_cache)
1418{
1419 bool ret = false;
1420
1421 spin_lock_bh(&fnhe_lock);
1422
1423 if (daddr == fnhe->fnhe_daddr) {
1424 struct rtable __rcu **porig;
1425 struct rtable *orig;
1426 int genid = fnhe_genid(dev_net(rt->dst.dev));
1427
1428 if (rt_is_input_route(rt))
1429 porig = &fnhe->fnhe_rth_input;
1430 else
1431 porig = &fnhe->fnhe_rth_output;
1432 orig = rcu_dereference(*porig);
1433
1434 if (fnhe->fnhe_genid != genid) {
1435 fnhe->fnhe_genid = genid;
1436 fnhe->fnhe_gw = 0;
1437 fnhe->fnhe_pmtu = 0;
1438 fnhe->fnhe_expires = 0;
1439 fnhe->fnhe_mtu_locked = false;
1440 fnhe_flush_routes(fnhe);
1441 orig = NULL;
1442 }
1443 fill_route_from_fnhe(rt, fnhe);
1444 if (!rt->rt_gw4) {
1445 rt->rt_gw4 = daddr;
1446 rt->rt_gw_family = AF_INET;
1447 }
1448
1449 if (do_cache) {
1450 dst_hold(&rt->dst);
1451 rcu_assign_pointer(*porig, rt);
1452 if (orig) {
1453 dst_dev_put(&orig->dst);
1454 dst_release(&orig->dst);
1455 }
1456 ret = true;
1457 }
1458
1459 fnhe->fnhe_stamp = jiffies;
1460 }
1461 spin_unlock_bh(&fnhe_lock);
1462
1463 return ret;
1464}
1465
1466static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1467{
1468 struct rtable *orig, *prev, **p;
1469 bool ret = true;
1470
1471 if (rt_is_input_route(rt)) {
1472 p = (struct rtable **)&nhc->nhc_rth_input;
1473 } else {
1474 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1475 }
1476 orig = *p;
1477
1478 /* hold dst before doing cmpxchg() to avoid race condition
1479 * on this dst
1480 */
1481 dst_hold(&rt->dst);
1482 prev = cmpxchg(p, orig, rt);
1483 if (prev == orig) {
1484 if (orig) {
1485 rt_add_uncached_list(orig);
1486 dst_release(&orig->dst);
1487 }
1488 } else {
1489 dst_release(&rt->dst);
1490 ret = false;
1491 }
1492
1493 return ret;
1494}
1495
1496struct uncached_list {
1497 spinlock_t lock;
1498 struct list_head head;
1499};
1500
1501static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1502
1503void rt_add_uncached_list(struct rtable *rt)
1504{
1505 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1506
1507 rt->rt_uncached_list = ul;
1508
1509 spin_lock_bh(&ul->lock);
1510 list_add_tail(&rt->rt_uncached, &ul->head);
1511 spin_unlock_bh(&ul->lock);
1512}
1513
1514void rt_del_uncached_list(struct rtable *rt)
1515{
1516 if (!list_empty(&rt->rt_uncached)) {
1517 struct uncached_list *ul = rt->rt_uncached_list;
1518
1519 spin_lock_bh(&ul->lock);
1520 list_del(&rt->rt_uncached);
1521 spin_unlock_bh(&ul->lock);
1522 }
1523}
1524
1525static void ipv4_dst_destroy(struct dst_entry *dst)
1526{
1527 struct rtable *rt = (struct rtable *)dst;
1528
1529 ip_dst_metrics_put(dst);
1530 rt_del_uncached_list(rt);
1531}
1532
1533void rt_flush_dev(struct net_device *dev)
1534{
1535 struct rtable *rt;
1536 int cpu;
1537
1538 for_each_possible_cpu(cpu) {
1539 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1540
1541 spin_lock_bh(&ul->lock);
1542 list_for_each_entry(rt, &ul->head, rt_uncached) {
1543 if (rt->dst.dev != dev)
1544 continue;
1545 rt->dst.dev = blackhole_netdev;
1546 dev_hold(rt->dst.dev);
1547 dev_put(dev);
1548 }
1549 spin_unlock_bh(&ul->lock);
1550 }
1551}
1552
1553static bool rt_cache_valid(const struct rtable *rt)
1554{
1555 return rt &&
1556 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1557 !rt_is_expired(rt);
1558}
1559
1560static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1561 const struct fib_result *res,
1562 struct fib_nh_exception *fnhe,
1563 struct fib_info *fi, u16 type, u32 itag,
1564 const bool do_cache)
1565{
1566 bool cached = false;
1567
1568 if (fi) {
1569 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1570
1571 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1572 rt->rt_uses_gateway = 1;
1573 rt->rt_gw_family = nhc->nhc_gw_family;
1574 /* only INET and INET6 are supported */
1575 if (likely(nhc->nhc_gw_family == AF_INET))
1576 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1577 else
1578 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1579 }
1580
1581 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1582
1583#ifdef CONFIG_IP_ROUTE_CLASSID
1584 if (nhc->nhc_family == AF_INET) {
1585 struct fib_nh *nh;
1586
1587 nh = container_of(nhc, struct fib_nh, nh_common);
1588 rt->dst.tclassid = nh->nh_tclassid;
1589 }
1590#endif
1591 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1592 if (unlikely(fnhe))
1593 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1594 else if (do_cache)
1595 cached = rt_cache_route(nhc, rt);
1596 if (unlikely(!cached)) {
1597 /* Routes we intend to cache in nexthop exception or
1598 * FIB nexthop have the DST_NOCACHE bit clear.
1599 * However, if we are unsuccessful at storing this
1600 * route into the cache we really need to set it.
1601 */
1602 if (!rt->rt_gw4) {
1603 rt->rt_gw_family = AF_INET;
1604 rt->rt_gw4 = daddr;
1605 }
1606 rt_add_uncached_list(rt);
1607 }
1608 } else
1609 rt_add_uncached_list(rt);
1610
1611#ifdef CONFIG_IP_ROUTE_CLASSID
1612#ifdef CONFIG_IP_MULTIPLE_TABLES
1613 set_class_tag(rt, res->tclassid);
1614#endif
1615 set_class_tag(rt, itag);
1616#endif
1617}
1618
1619struct rtable *rt_dst_alloc(struct net_device *dev,
1620 unsigned int flags, u16 type,
1621 bool nopolicy, bool noxfrm, bool will_cache)
1622{
1623 struct rtable *rt;
1624
1625 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1626 (will_cache ? 0 : DST_HOST) |
1627 (nopolicy ? DST_NOPOLICY : 0) |
1628 (noxfrm ? DST_NOXFRM : 0));
1629
1630 if (rt) {
1631 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1632 rt->rt_flags = flags;
1633 rt->rt_type = type;
1634 rt->rt_is_input = 0;
1635 rt->rt_iif = 0;
1636 rt->rt_pmtu = 0;
1637 rt->rt_mtu_locked = 0;
1638 rt->rt_uses_gateway = 0;
1639 rt->rt_gw_family = 0;
1640 rt->rt_gw4 = 0;
1641 INIT_LIST_HEAD(&rt->rt_uncached);
1642
1643 rt->dst.output = ip_output;
1644 if (flags & RTCF_LOCAL)
1645 rt->dst.input = ip_local_deliver;
1646 }
1647
1648 return rt;
1649}
1650EXPORT_SYMBOL(rt_dst_alloc);
1651
1652struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1653{
1654 struct rtable *new_rt;
1655
1656 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1657 rt->dst.flags);
1658
1659 if (new_rt) {
1660 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1661 new_rt->rt_flags = rt->rt_flags;
1662 new_rt->rt_type = rt->rt_type;
1663 new_rt->rt_is_input = rt->rt_is_input;
1664 new_rt->rt_iif = rt->rt_iif;
1665 new_rt->rt_pmtu = rt->rt_pmtu;
1666 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1667 new_rt->rt_gw_family = rt->rt_gw_family;
1668 if (rt->rt_gw_family == AF_INET)
1669 new_rt->rt_gw4 = rt->rt_gw4;
1670 else if (rt->rt_gw_family == AF_INET6)
1671 new_rt->rt_gw6 = rt->rt_gw6;
1672 INIT_LIST_HEAD(&new_rt->rt_uncached);
1673
1674 new_rt->dst.flags |= DST_HOST;
1675 new_rt->dst.input = rt->dst.input;
1676 new_rt->dst.output = rt->dst.output;
1677 new_rt->dst.error = rt->dst.error;
1678 new_rt->dst.lastuse = jiffies;
1679 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1680 }
1681 return new_rt;
1682}
1683EXPORT_SYMBOL(rt_dst_clone);
1684
1685/* called in rcu_read_lock() section */
1686int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1687 u8 tos, struct net_device *dev,
1688 struct in_device *in_dev, u32 *itag)
1689{
1690 int err;
1691
1692 /* Primary sanity checks. */
1693 if (!in_dev)
1694 return -EINVAL;
1695
1696 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1697 skb->protocol != htons(ETH_P_IP))
1698 return -EINVAL;
1699
1700 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1701 return -EINVAL;
1702
1703 if (ipv4_is_zeronet(saddr)) {
1704 if (!ipv4_is_local_multicast(daddr) &&
1705 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1706 return -EINVAL;
1707 } else {
1708 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1709 in_dev, itag);
1710 if (err < 0)
1711 return err;
1712 }
1713 return 0;
1714}
1715
1716/* called in rcu_read_lock() section */
1717static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1718 u8 tos, struct net_device *dev, int our)
1719{
1720 struct in_device *in_dev = __in_dev_get_rcu(dev);
1721 unsigned int flags = RTCF_MULTICAST;
1722 struct rtable *rth;
1723 u32 itag = 0;
1724 int err;
1725
1726 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1727 if (err)
1728 return err;
1729
1730 if (our)
1731 flags |= RTCF_LOCAL;
1732
1733 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1734 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1735 if (!rth)
1736 return -ENOBUFS;
1737
1738#ifdef CONFIG_IP_ROUTE_CLASSID
1739 rth->dst.tclassid = itag;
1740#endif
1741 rth->dst.output = ip_rt_bug;
1742 rth->rt_is_input= 1;
1743
1744#ifdef CONFIG_IP_MROUTE
1745 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1746 rth->dst.input = ip_mr_input;
1747#endif
1748 RT_CACHE_STAT_INC(in_slow_mc);
1749
1750 skb_dst_set(skb, &rth->dst);
1751 return 0;
1752}
1753
1754
1755static void ip_handle_martian_source(struct net_device *dev,
1756 struct in_device *in_dev,
1757 struct sk_buff *skb,
1758 __be32 daddr,
1759 __be32 saddr)
1760{
1761 RT_CACHE_STAT_INC(in_martian_src);
1762#ifdef CONFIG_IP_ROUTE_VERBOSE
1763 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1764 /*
1765 * RFC1812 recommendation, if source is martian,
1766 * the only hint is MAC header.
1767 */
1768 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1769 &daddr, &saddr, dev->name);
1770 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1771 print_hex_dump(KERN_WARNING, "ll header: ",
1772 DUMP_PREFIX_OFFSET, 16, 1,
1773 skb_mac_header(skb),
1774 dev->hard_header_len, false);
1775 }
1776 }
1777#endif
1778}
1779
1780/* called in rcu_read_lock() section */
1781static int __mkroute_input(struct sk_buff *skb,
1782 const struct fib_result *res,
1783 struct in_device *in_dev,
1784 __be32 daddr, __be32 saddr, u32 tos)
1785{
1786 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1787 struct net_device *dev = nhc->nhc_dev;
1788 struct fib_nh_exception *fnhe;
1789 struct rtable *rth;
1790 int err;
1791 struct in_device *out_dev;
1792 bool do_cache;
1793 u32 itag = 0;
1794
1795 /* get a working reference to the output device */
1796 out_dev = __in_dev_get_rcu(dev);
1797 if (!out_dev) {
1798 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1799 return -EINVAL;
1800 }
1801
1802 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1803 in_dev->dev, in_dev, &itag);
1804 if (err < 0) {
1805 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1806 saddr);
1807
1808 goto cleanup;
1809 }
1810
1811 do_cache = res->fi && !itag;
1812 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1813 skb->protocol == htons(ETH_P_IP)) {
1814 __be32 gw;
1815
1816 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1817 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1818 inet_addr_onlink(out_dev, saddr, gw))
1819 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1820 }
1821
1822 if (skb->protocol != htons(ETH_P_IP)) {
1823 /* Not IP (i.e. ARP). Do not create route, if it is
1824 * invalid for proxy arp. DNAT routes are always valid.
1825 *
1826 * Proxy arp feature have been extended to allow, ARP
1827 * replies back to the same interface, to support
1828 * Private VLAN switch technologies. See arp.c.
1829 */
1830 if (out_dev == in_dev &&
1831 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1832 err = -EINVAL;
1833 goto cleanup;
1834 }
1835 }
1836
1837 fnhe = find_exception(nhc, daddr);
1838 if (do_cache) {
1839 if (fnhe)
1840 rth = rcu_dereference(fnhe->fnhe_rth_input);
1841 else
1842 rth = rcu_dereference(nhc->nhc_rth_input);
1843 if (rt_cache_valid(rth)) {
1844 skb_dst_set_noref(skb, &rth->dst);
1845 goto out;
1846 }
1847 }
1848
1849 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1850 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1851 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1852 if (!rth) {
1853 err = -ENOBUFS;
1854 goto cleanup;
1855 }
1856
1857 rth->rt_is_input = 1;
1858 RT_CACHE_STAT_INC(in_slow_tot);
1859
1860 rth->dst.input = ip_forward;
1861
1862 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1863 do_cache);
1864 lwtunnel_set_redirect(&rth->dst);
1865 skb_dst_set(skb, &rth->dst);
1866out:
1867 err = 0;
1868 cleanup:
1869 return err;
1870}
1871
1872#ifdef CONFIG_IP_ROUTE_MULTIPATH
1873/* To make ICMP packets follow the right flow, the multipath hash is
1874 * calculated from the inner IP addresses.
1875 */
1876static void ip_multipath_l3_keys(const struct sk_buff *skb,
1877 struct flow_keys *hash_keys)
1878{
1879 const struct iphdr *outer_iph = ip_hdr(skb);
1880 const struct iphdr *key_iph = outer_iph;
1881 const struct iphdr *inner_iph;
1882 const struct icmphdr *icmph;
1883 struct iphdr _inner_iph;
1884 struct icmphdr _icmph;
1885
1886 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1887 goto out;
1888
1889 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1890 goto out;
1891
1892 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1893 &_icmph);
1894 if (!icmph)
1895 goto out;
1896
1897 if (icmph->type != ICMP_DEST_UNREACH &&
1898 icmph->type != ICMP_REDIRECT &&
1899 icmph->type != ICMP_TIME_EXCEEDED &&
1900 icmph->type != ICMP_PARAMETERPROB)
1901 goto out;
1902
1903 inner_iph = skb_header_pointer(skb,
1904 outer_iph->ihl * 4 + sizeof(_icmph),
1905 sizeof(_inner_iph), &_inner_iph);
1906 if (!inner_iph)
1907 goto out;
1908
1909 key_iph = inner_iph;
1910out:
1911 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1912 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1913}
1914
1915/* if skb is set it will be used and fl4 can be NULL */
1916int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1917 const struct sk_buff *skb, struct flow_keys *flkeys)
1918{
1919 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
1920 struct flow_keys hash_keys;
1921 u32 mhash;
1922
1923 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1924 case 0:
1925 memset(&hash_keys, 0, sizeof(hash_keys));
1926 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1927 if (skb) {
1928 ip_multipath_l3_keys(skb, &hash_keys);
1929 } else {
1930 hash_keys.addrs.v4addrs.src = fl4->saddr;
1931 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1932 }
1933 break;
1934 case 1:
1935 /* skb is currently provided only when forwarding */
1936 if (skb) {
1937 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1938 struct flow_keys keys;
1939
1940 /* short-circuit if we already have L4 hash present */
1941 if (skb->l4_hash)
1942 return skb_get_hash_raw(skb) >> 1;
1943
1944 memset(&hash_keys, 0, sizeof(hash_keys));
1945
1946 if (!flkeys) {
1947 skb_flow_dissect_flow_keys(skb, &keys, flag);
1948 flkeys = &keys;
1949 }
1950
1951 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1952 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1953 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1954 hash_keys.ports.src = flkeys->ports.src;
1955 hash_keys.ports.dst = flkeys->ports.dst;
1956 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1957 } else {
1958 memset(&hash_keys, 0, sizeof(hash_keys));
1959 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1960 hash_keys.addrs.v4addrs.src = fl4->saddr;
1961 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1962 hash_keys.ports.src = fl4->fl4_sport;
1963 hash_keys.ports.dst = fl4->fl4_dport;
1964 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1965 }
1966 break;
1967 case 2:
1968 memset(&hash_keys, 0, sizeof(hash_keys));
1969 /* skb is currently provided only when forwarding */
1970 if (skb) {
1971 struct flow_keys keys;
1972
1973 skb_flow_dissect_flow_keys(skb, &keys, 0);
1974 /* Inner can be v4 or v6 */
1975 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1976 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1977 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1978 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1979 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1980 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1981 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1982 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1983 hash_keys.tags.flow_label = keys.tags.flow_label;
1984 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1985 } else {
1986 /* Same as case 0 */
1987 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1988 ip_multipath_l3_keys(skb, &hash_keys);
1989 }
1990 } else {
1991 /* Same as case 0 */
1992 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1993 hash_keys.addrs.v4addrs.src = fl4->saddr;
1994 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1995 }
1996 break;
1997 }
1998 mhash = flow_hash_from_keys(&hash_keys);
1999
2000 if (multipath_hash)
2001 mhash = jhash_2words(mhash, multipath_hash, 0);
2002
2003 return mhash >> 1;
2004}
2005#endif /* CONFIG_IP_ROUTE_MULTIPATH */
2006
2007static int ip_mkroute_input(struct sk_buff *skb,
2008 struct fib_result *res,
2009 struct in_device *in_dev,
2010 __be32 daddr, __be32 saddr, u32 tos,
2011 struct flow_keys *hkeys)
2012{
2013#ifdef CONFIG_IP_ROUTE_MULTIPATH
2014 if (res->fi && fib_info_num_path(res->fi) > 1) {
2015 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2016
2017 fib_select_multipath(res, h);
2018 }
2019#endif
2020
2021 /* create a routing cache entry */
2022 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2023}
2024
2025/*
2026 * NOTE. We drop all the packets that has local source
2027 * addresses, because every properly looped back packet
2028 * must have correct destination already attached by output routine.
2029 *
2030 * Such approach solves two big problems:
2031 * 1. Not simplex devices are handled properly.
2032 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2033 * called with rcu_read_lock()
2034 */
2035
2036static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2037 u8 tos, struct net_device *dev,
2038 struct fib_result *res)
2039{
2040 struct in_device *in_dev = __in_dev_get_rcu(dev);
2041 struct flow_keys *flkeys = NULL, _flkeys;
2042 struct net *net = dev_net(dev);
2043 struct ip_tunnel_info *tun_info;
2044 int err = -EINVAL;
2045 unsigned int flags = 0;
2046 u32 itag = 0;
2047 struct rtable *rth;
2048 struct flowi4 fl4;
2049 bool do_cache = true;
2050
2051 /* IP on this device is disabled. */
2052
2053 if (!in_dev)
2054 goto out;
2055
2056 /* Check for the most weird martians, which can be not detected
2057 by fib_lookup.
2058 */
2059
2060 tun_info = skb_tunnel_info(skb);
2061 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2062 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2063 else
2064 fl4.flowi4_tun_key.tun_id = 0;
2065 skb_dst_drop(skb);
2066
2067 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2068 goto martian_source;
2069
2070 res->fi = NULL;
2071 res->table = NULL;
2072 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2073 goto brd_input;
2074
2075 /* Accept zero addresses only to limited broadcast;
2076 * I even do not know to fix it or not. Waiting for complains :-)
2077 */
2078 if (ipv4_is_zeronet(saddr))
2079 goto martian_source;
2080
2081 if (ipv4_is_zeronet(daddr))
2082 goto martian_destination;
2083
2084 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2085 * and call it once if daddr or/and saddr are loopback addresses
2086 */
2087 if (ipv4_is_loopback(daddr)) {
2088 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2089 goto martian_destination;
2090 } else if (ipv4_is_loopback(saddr)) {
2091 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2092 goto martian_source;
2093 }
2094
2095 /*
2096 * Now we are ready to route packet.
2097 */
2098 fl4.flowi4_oif = 0;
2099 fl4.flowi4_iif = dev->ifindex;
2100 fl4.flowi4_mark = skb->mark;
2101 fl4.flowi4_tos = tos;
2102 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2103 fl4.flowi4_flags = 0;
2104 fl4.daddr = daddr;
2105 fl4.saddr = saddr;
2106 fl4.flowi4_uid = sock_net_uid(net, NULL);
2107
2108 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2109 flkeys = &_flkeys;
2110 } else {
2111 fl4.flowi4_proto = 0;
2112 fl4.fl4_sport = 0;
2113 fl4.fl4_dport = 0;
2114 }
2115
2116 err = fib_lookup(net, &fl4, res, 0);
2117 if (err != 0) {
2118 if (!IN_DEV_FORWARD(in_dev))
2119 err = -EHOSTUNREACH;
2120 goto no_route;
2121 }
2122
2123 if (res->type == RTN_BROADCAST) {
2124 if (IN_DEV_BFORWARD(in_dev))
2125 goto make_route;
2126 /* not do cache if bc_forwarding is enabled */
2127 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))
2128 do_cache = false;
2129 goto brd_input;
2130 }
2131
2132 if (res->type == RTN_LOCAL) {
2133 err = fib_validate_source(skb, saddr, daddr, tos,
2134 0, dev, in_dev, &itag);
2135 if (err < 0)
2136 goto martian_source;
2137 goto local_input;
2138 }
2139
2140 if (!IN_DEV_FORWARD(in_dev)) {
2141 err = -EHOSTUNREACH;
2142 goto no_route;
2143 }
2144 if (res->type != RTN_UNICAST)
2145 goto martian_destination;
2146
2147make_route:
2148 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2149out: return err;
2150
2151brd_input:
2152 if (skb->protocol != htons(ETH_P_IP))
2153 goto e_inval;
2154
2155 if (!ipv4_is_zeronet(saddr)) {
2156 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2157 in_dev, &itag);
2158 if (err < 0)
2159 goto martian_source;
2160 }
2161 flags |= RTCF_BROADCAST;
2162 res->type = RTN_BROADCAST;
2163 RT_CACHE_STAT_INC(in_brd);
2164
2165local_input:
2166 do_cache &= res->fi && !itag;
2167 if (do_cache) {
2168 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2169
2170 rth = rcu_dereference(nhc->nhc_rth_input);
2171 if (rt_cache_valid(rth)) {
2172 skb_dst_set_noref(skb, &rth->dst);
2173 err = 0;
2174 goto out;
2175 }
2176 }
2177
2178 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2179 flags | RTCF_LOCAL, res->type,
2180 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2181 if (!rth)
2182 goto e_nobufs;
2183
2184 rth->dst.output= ip_rt_bug;
2185#ifdef CONFIG_IP_ROUTE_CLASSID
2186 rth->dst.tclassid = itag;
2187#endif
2188 rth->rt_is_input = 1;
2189
2190 RT_CACHE_STAT_INC(in_slow_tot);
2191 if (res->type == RTN_UNREACHABLE) {
2192 rth->dst.input= ip_error;
2193 rth->dst.error= -err;
2194 rth->rt_flags &= ~RTCF_LOCAL;
2195 }
2196
2197 if (do_cache) {
2198 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2199
2200 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2201 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2202 WARN_ON(rth->dst.input == lwtunnel_input);
2203 rth->dst.lwtstate->orig_input = rth->dst.input;
2204 rth->dst.input = lwtunnel_input;
2205 }
2206
2207 if (unlikely(!rt_cache_route(nhc, rth)))
2208 rt_add_uncached_list(rth);
2209 }
2210 skb_dst_set(skb, &rth->dst);
2211 err = 0;
2212 goto out;
2213
2214no_route:
2215 RT_CACHE_STAT_INC(in_no_route);
2216 res->type = RTN_UNREACHABLE;
2217 res->fi = NULL;
2218 res->table = NULL;
2219 goto local_input;
2220
2221 /*
2222 * Do not cache martian addresses: they should be logged (RFC1812)
2223 */
2224martian_destination:
2225 RT_CACHE_STAT_INC(in_martian_dst);
2226#ifdef CONFIG_IP_ROUTE_VERBOSE
2227 if (IN_DEV_LOG_MARTIANS(in_dev))
2228 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2229 &daddr, &saddr, dev->name);
2230#endif
2231
2232e_inval:
2233 err = -EINVAL;
2234 goto out;
2235
2236e_nobufs:
2237 err = -ENOBUFS;
2238 goto out;
2239
2240martian_source:
2241 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2242 goto out;
2243}
2244
2245int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2246 u8 tos, struct net_device *dev)
2247{
2248 struct fib_result res;
2249 int err;
2250
2251 tos &= IPTOS_RT_MASK;
2252 rcu_read_lock();
2253 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2254 rcu_read_unlock();
2255
2256 return err;
2257}
2258EXPORT_SYMBOL(ip_route_input_noref);
2259
2260/* called with rcu_read_lock held */
2261int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2262 u8 tos, struct net_device *dev, struct fib_result *res)
2263{
2264 /* Multicast recognition logic is moved from route cache to here.
2265 The problem was that too many Ethernet cards have broken/missing
2266 hardware multicast filters :-( As result the host on multicasting
2267 network acquires a lot of useless route cache entries, sort of
2268 SDR messages from all the world. Now we try to get rid of them.
2269 Really, provided software IP multicast filter is organized
2270 reasonably (at least, hashed), it does not result in a slowdown
2271 comparing with route cache reject entries.
2272 Note, that multicast routers are not affected, because
2273 route cache entry is created eventually.
2274 */
2275 if (ipv4_is_multicast(daddr)) {
2276 struct in_device *in_dev = __in_dev_get_rcu(dev);
2277 int our = 0;
2278 int err = -EINVAL;
2279
2280 if (!in_dev)
2281 return err;
2282 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2283 ip_hdr(skb)->protocol);
2284
2285 /* check l3 master if no match yet */
2286 if (!our && netif_is_l3_slave(dev)) {
2287 struct in_device *l3_in_dev;
2288
2289 l3_in_dev = __in_dev_get_rcu(skb->dev);
2290 if (l3_in_dev)
2291 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2292 ip_hdr(skb)->protocol);
2293 }
2294
2295 if (our
2296#ifdef CONFIG_IP_MROUTE
2297 ||
2298 (!ipv4_is_local_multicast(daddr) &&
2299 IN_DEV_MFORWARD(in_dev))
2300#endif
2301 ) {
2302 err = ip_route_input_mc(skb, daddr, saddr,
2303 tos, dev, our);
2304 }
2305 return err;
2306 }
2307
2308 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2309}
2310
2311/* called with rcu_read_lock() */
2312static struct rtable *__mkroute_output(const struct fib_result *res,
2313 const struct flowi4 *fl4, int orig_oif,
2314 struct net_device *dev_out,
2315 unsigned int flags)
2316{
2317 struct fib_info *fi = res->fi;
2318 struct fib_nh_exception *fnhe;
2319 struct in_device *in_dev;
2320 u16 type = res->type;
2321 struct rtable *rth;
2322 bool do_cache;
2323
2324 in_dev = __in_dev_get_rcu(dev_out);
2325 if (!in_dev)
2326 return ERR_PTR(-EINVAL);
2327
2328 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2329 if (ipv4_is_loopback(fl4->saddr) &&
2330 !(dev_out->flags & IFF_LOOPBACK) &&
2331 !netif_is_l3_master(dev_out))
2332 return ERR_PTR(-EINVAL);
2333
2334 if (ipv4_is_lbcast(fl4->daddr))
2335 type = RTN_BROADCAST;
2336 else if (ipv4_is_multicast(fl4->daddr))
2337 type = RTN_MULTICAST;
2338 else if (ipv4_is_zeronet(fl4->daddr))
2339 return ERR_PTR(-EINVAL);
2340
2341 if (dev_out->flags & IFF_LOOPBACK)
2342 flags |= RTCF_LOCAL;
2343
2344 do_cache = true;
2345 if (type == RTN_BROADCAST) {
2346 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2347 fi = NULL;
2348 } else if (type == RTN_MULTICAST) {
2349 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2350 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2351 fl4->flowi4_proto))
2352 flags &= ~RTCF_LOCAL;
2353 else
2354 do_cache = false;
2355 /* If multicast route do not exist use
2356 * default one, but do not gateway in this case.
2357 * Yes, it is hack.
2358 */
2359 if (fi && res->prefixlen < 4)
2360 fi = NULL;
2361 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2362 (orig_oif != dev_out->ifindex)) {
2363 /* For local routes that require a particular output interface
2364 * we do not want to cache the result. Caching the result
2365 * causes incorrect behaviour when there are multiple source
2366 * addresses on the interface, the end result being that if the
2367 * intended recipient is waiting on that interface for the
2368 * packet he won't receive it because it will be delivered on
2369 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2370 * be set to the loopback interface as well.
2371 */
2372 do_cache = false;
2373 }
2374
2375 fnhe = NULL;
2376 do_cache &= fi != NULL;
2377 if (fi) {
2378 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2379 struct rtable __rcu **prth;
2380
2381 fnhe = find_exception(nhc, fl4->daddr);
2382 if (!do_cache)
2383 goto add;
2384 if (fnhe) {
2385 prth = &fnhe->fnhe_rth_output;
2386 } else {
2387 if (unlikely(fl4->flowi4_flags &
2388 FLOWI_FLAG_KNOWN_NH &&
2389 !(nhc->nhc_gw_family &&
2390 nhc->nhc_scope == RT_SCOPE_LINK))) {
2391 do_cache = false;
2392 goto add;
2393 }
2394 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2395 }
2396 rth = rcu_dereference(*prth);
2397 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2398 return rth;
2399 }
2400
2401add:
2402 rth = rt_dst_alloc(dev_out, flags, type,
2403 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2404 IN_DEV_CONF_GET(in_dev, NOXFRM),
2405 do_cache);
2406 if (!rth)
2407 return ERR_PTR(-ENOBUFS);
2408
2409 rth->rt_iif = orig_oif;
2410
2411 RT_CACHE_STAT_INC(out_slow_tot);
2412
2413 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2414 if (flags & RTCF_LOCAL &&
2415 !(dev_out->flags & IFF_LOOPBACK)) {
2416 rth->dst.output = ip_mc_output;
2417 RT_CACHE_STAT_INC(out_slow_mc);
2418 }
2419#ifdef CONFIG_IP_MROUTE
2420 if (type == RTN_MULTICAST) {
2421 if (IN_DEV_MFORWARD(in_dev) &&
2422 !ipv4_is_local_multicast(fl4->daddr)) {
2423 rth->dst.input = ip_mr_input;
2424 rth->dst.output = ip_mc_output;
2425 }
2426 }
2427#endif
2428 }
2429
2430 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2431 lwtunnel_set_redirect(&rth->dst);
2432
2433 return rth;
2434}
2435
2436/*
2437 * Major route resolver routine.
2438 */
2439
2440struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2441 const struct sk_buff *skb)
2442{
2443 __u8 tos = RT_FL_TOS(fl4);
2444 struct fib_result res = {
2445 .type = RTN_UNSPEC,
2446 .fi = NULL,
2447 .table = NULL,
2448 .tclassid = 0,
2449 };
2450 struct rtable *rth;
2451
2452 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2453 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2454 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2455 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2456
2457 rcu_read_lock();
2458 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2459 rcu_read_unlock();
2460
2461 return rth;
2462}
2463EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2464
2465struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2466 struct fib_result *res,
2467 const struct sk_buff *skb)
2468{
2469 struct net_device *dev_out = NULL;
2470 int orig_oif = fl4->flowi4_oif;
2471 unsigned int flags = 0;
2472 struct rtable *rth;
2473 int err;
2474
2475 if (fl4->saddr) {
2476 if (ipv4_is_multicast(fl4->saddr) ||
2477 ipv4_is_lbcast(fl4->saddr) ||
2478 ipv4_is_zeronet(fl4->saddr)) {
2479 rth = ERR_PTR(-EINVAL);
2480 goto out;
2481 }
2482
2483 rth = ERR_PTR(-ENETUNREACH);
2484
2485 /* I removed check for oif == dev_out->oif here.
2486 It was wrong for two reasons:
2487 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2488 is assigned to multiple interfaces.
2489 2. Moreover, we are allowed to send packets with saddr
2490 of another iface. --ANK
2491 */
2492
2493 if (fl4->flowi4_oif == 0 &&
2494 (ipv4_is_multicast(fl4->daddr) ||
2495 ipv4_is_lbcast(fl4->daddr))) {
2496 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2497 dev_out = __ip_dev_find(net, fl4->saddr, false);
2498 if (!dev_out)
2499 goto out;
2500
2501 /* Special hack: user can direct multicasts
2502 and limited broadcast via necessary interface
2503 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2504 This hack is not just for fun, it allows
2505 vic,vat and friends to work.
2506 They bind socket to loopback, set ttl to zero
2507 and expect that it will work.
2508 From the viewpoint of routing cache they are broken,
2509 because we are not allowed to build multicast path
2510 with loopback source addr (look, routing cache
2511 cannot know, that ttl is zero, so that packet
2512 will not leave this host and route is valid).
2513 Luckily, this hack is good workaround.
2514 */
2515
2516 fl4->flowi4_oif = dev_out->ifindex;
2517 goto make_route;
2518 }
2519
2520 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2521 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2522 if (!__ip_dev_find(net, fl4->saddr, false))
2523 goto out;
2524 }
2525 }
2526
2527
2528 if (fl4->flowi4_oif) {
2529 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2530 rth = ERR_PTR(-ENODEV);
2531 if (!dev_out)
2532 goto out;
2533
2534 /* RACE: Check return value of inet_select_addr instead. */
2535 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2536 rth = ERR_PTR(-ENETUNREACH);
2537 goto out;
2538 }
2539 if (ipv4_is_local_multicast(fl4->daddr) ||
2540 ipv4_is_lbcast(fl4->daddr) ||
2541 fl4->flowi4_proto == IPPROTO_IGMP) {
2542 if (!fl4->saddr)
2543 fl4->saddr = inet_select_addr(dev_out, 0,
2544 RT_SCOPE_LINK);
2545 goto make_route;
2546 }
2547 if (!fl4->saddr) {
2548 if (ipv4_is_multicast(fl4->daddr))
2549 fl4->saddr = inet_select_addr(dev_out, 0,
2550 fl4->flowi4_scope);
2551 else if (!fl4->daddr)
2552 fl4->saddr = inet_select_addr(dev_out, 0,
2553 RT_SCOPE_HOST);
2554 }
2555 }
2556
2557 if (!fl4->daddr) {
2558 fl4->daddr = fl4->saddr;
2559 if (!fl4->daddr)
2560 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2561 dev_out = net->loopback_dev;
2562 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2563 res->type = RTN_LOCAL;
2564 flags |= RTCF_LOCAL;
2565 goto make_route;
2566 }
2567
2568 err = fib_lookup(net, fl4, res, 0);
2569 if (err) {
2570 res->fi = NULL;
2571 res->table = NULL;
2572 if (fl4->flowi4_oif &&
2573 (ipv4_is_multicast(fl4->daddr) ||
2574 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2575 /* Apparently, routing tables are wrong. Assume,
2576 that the destination is on link.
2577
2578 WHY? DW.
2579 Because we are allowed to send to iface
2580 even if it has NO routes and NO assigned
2581 addresses. When oif is specified, routing
2582 tables are looked up with only one purpose:
2583 to catch if destination is gatewayed, rather than
2584 direct. Moreover, if MSG_DONTROUTE is set,
2585 we send packet, ignoring both routing tables
2586 and ifaddr state. --ANK
2587
2588
2589 We could make it even if oif is unknown,
2590 likely IPv6, but we do not.
2591 */
2592
2593 if (fl4->saddr == 0)
2594 fl4->saddr = inet_select_addr(dev_out, 0,
2595 RT_SCOPE_LINK);
2596 res->type = RTN_UNICAST;
2597 goto make_route;
2598 }
2599 rth = ERR_PTR(err);
2600 goto out;
2601 }
2602
2603 if (res->type == RTN_LOCAL) {
2604 if (!fl4->saddr) {
2605 if (res->fi->fib_prefsrc)
2606 fl4->saddr = res->fi->fib_prefsrc;
2607 else
2608 fl4->saddr = fl4->daddr;
2609 }
2610
2611 /* L3 master device is the loopback for that domain */
2612 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2613 net->loopback_dev;
2614
2615 /* make sure orig_oif points to fib result device even
2616 * though packet rx/tx happens over loopback or l3mdev
2617 */
2618 orig_oif = FIB_RES_OIF(*res);
2619
2620 fl4->flowi4_oif = dev_out->ifindex;
2621 flags |= RTCF_LOCAL;
2622 goto make_route;
2623 }
2624
2625 fib_select_path(net, res, fl4, skb);
2626
2627 dev_out = FIB_RES_DEV(*res);
2628 fl4->flowi4_oif = dev_out->ifindex;
2629
2630
2631make_route:
2632 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2633
2634out:
2635 return rth;
2636}
2637
2638static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2639{
2640 return NULL;
2641}
2642
2643static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2644{
2645 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2646
2647 return mtu ? : dst->dev->mtu;
2648}
2649
2650static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2651 struct sk_buff *skb, u32 mtu)
2652{
2653}
2654
2655static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2656 struct sk_buff *skb)
2657{
2658}
2659
2660static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2661 unsigned long old)
2662{
2663 return NULL;
2664}
2665
2666static struct dst_ops ipv4_dst_blackhole_ops = {
2667 .family = AF_INET,
2668 .check = ipv4_blackhole_dst_check,
2669 .mtu = ipv4_blackhole_mtu,
2670 .default_advmss = ipv4_default_advmss,
2671 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2672 .redirect = ipv4_rt_blackhole_redirect,
2673 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2674 .neigh_lookup = ipv4_neigh_lookup,
2675};
2676
2677struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2678{
2679 struct rtable *ort = (struct rtable *) dst_orig;
2680 struct rtable *rt;
2681
2682 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2683 if (rt) {
2684 struct dst_entry *new = &rt->dst;
2685
2686 new->__use = 1;
2687 new->input = dst_discard;
2688 new->output = dst_discard_out;
2689
2690 new->dev = net->loopback_dev;
2691 if (new->dev)
2692 dev_hold(new->dev);
2693
2694 rt->rt_is_input = ort->rt_is_input;
2695 rt->rt_iif = ort->rt_iif;
2696 rt->rt_pmtu = ort->rt_pmtu;
2697 rt->rt_mtu_locked = ort->rt_mtu_locked;
2698
2699 rt->rt_genid = rt_genid_ipv4(net);
2700 rt->rt_flags = ort->rt_flags;
2701 rt->rt_type = ort->rt_type;
2702 rt->rt_uses_gateway = ort->rt_uses_gateway;
2703 rt->rt_gw_family = ort->rt_gw_family;
2704 if (rt->rt_gw_family == AF_INET)
2705 rt->rt_gw4 = ort->rt_gw4;
2706 else if (rt->rt_gw_family == AF_INET6)
2707 rt->rt_gw6 = ort->rt_gw6;
2708
2709 INIT_LIST_HEAD(&rt->rt_uncached);
2710 }
2711
2712 dst_release(dst_orig);
2713
2714 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2715}
2716
2717struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2718 const struct sock *sk)
2719{
2720 struct rtable *rt = __ip_route_output_key(net, flp4);
2721
2722 if (IS_ERR(rt))
2723 return rt;
2724
2725 if (flp4->flowi4_proto)
2726 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2727 flowi4_to_flowi(flp4),
2728 sk, 0);
2729
2730 return rt;
2731}
2732EXPORT_SYMBOL_GPL(ip_route_output_flow);
2733
2734/* called with rcu_read_lock held */
2735static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2736 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2737 struct sk_buff *skb, u32 portid, u32 seq,
2738 unsigned int flags)
2739{
2740 struct rtmsg *r;
2741 struct nlmsghdr *nlh;
2742 unsigned long expires = 0;
2743 u32 error;
2744 u32 metrics[RTAX_MAX];
2745
2746 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2747 if (!nlh)
2748 return -EMSGSIZE;
2749
2750 r = nlmsg_data(nlh);
2751 r->rtm_family = AF_INET;
2752 r->rtm_dst_len = 32;
2753 r->rtm_src_len = 0;
2754 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2755 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2756 if (nla_put_u32(skb, RTA_TABLE, table_id))
2757 goto nla_put_failure;
2758 r->rtm_type = rt->rt_type;
2759 r->rtm_scope = RT_SCOPE_UNIVERSE;
2760 r->rtm_protocol = RTPROT_UNSPEC;
2761 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2762 if (rt->rt_flags & RTCF_NOTIFY)
2763 r->rtm_flags |= RTM_F_NOTIFY;
2764 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2765 r->rtm_flags |= RTCF_DOREDIRECT;
2766
2767 if (nla_put_in_addr(skb, RTA_DST, dst))
2768 goto nla_put_failure;
2769 if (src) {
2770 r->rtm_src_len = 32;
2771 if (nla_put_in_addr(skb, RTA_SRC, src))
2772 goto nla_put_failure;
2773 }
2774 if (rt->dst.dev &&
2775 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2776 goto nla_put_failure;
2777#ifdef CONFIG_IP_ROUTE_CLASSID
2778 if (rt->dst.tclassid &&
2779 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2780 goto nla_put_failure;
2781#endif
2782 if (fl4 && !rt_is_input_route(rt) &&
2783 fl4->saddr != src) {
2784 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2785 goto nla_put_failure;
2786 }
2787 if (rt->rt_uses_gateway) {
2788 if (rt->rt_gw_family == AF_INET &&
2789 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2790 goto nla_put_failure;
2791 } else if (rt->rt_gw_family == AF_INET6) {
2792 int alen = sizeof(struct in6_addr);
2793 struct nlattr *nla;
2794 struct rtvia *via;
2795
2796 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2797 if (!nla)
2798 goto nla_put_failure;
2799
2800 via = nla_data(nla);
2801 via->rtvia_family = AF_INET6;
2802 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2803 }
2804 }
2805
2806 expires = rt->dst.expires;
2807 if (expires) {
2808 unsigned long now = jiffies;
2809
2810 if (time_before(now, expires))
2811 expires -= now;
2812 else
2813 expires = 0;
2814 }
2815
2816 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2817 if (rt->rt_pmtu && expires)
2818 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2819 if (rt->rt_mtu_locked && expires)
2820 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2821 if (rtnetlink_put_metrics(skb, metrics) < 0)
2822 goto nla_put_failure;
2823
2824 if (fl4) {
2825 if (fl4->flowi4_mark &&
2826 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2827 goto nla_put_failure;
2828
2829 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2830 nla_put_u32(skb, RTA_UID,
2831 from_kuid_munged(current_user_ns(),
2832 fl4->flowi4_uid)))
2833 goto nla_put_failure;
2834
2835 if (rt_is_input_route(rt)) {
2836#ifdef CONFIG_IP_MROUTE
2837 if (ipv4_is_multicast(dst) &&
2838 !ipv4_is_local_multicast(dst) &&
2839 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2840 int err = ipmr_get_route(net, skb,
2841 fl4->saddr, fl4->daddr,
2842 r, portid);
2843
2844 if (err <= 0) {
2845 if (err == 0)
2846 return 0;
2847 goto nla_put_failure;
2848 }
2849 } else
2850#endif
2851 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
2852 goto nla_put_failure;
2853 }
2854 }
2855
2856 error = rt->dst.error;
2857
2858 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2859 goto nla_put_failure;
2860
2861 nlmsg_end(skb, nlh);
2862 return 0;
2863
2864nla_put_failure:
2865 nlmsg_cancel(skb, nlh);
2866 return -EMSGSIZE;
2867}
2868
2869static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
2870 struct netlink_callback *cb, u32 table_id,
2871 struct fnhe_hash_bucket *bucket, int genid,
2872 int *fa_index, int fa_start, unsigned int flags)
2873{
2874 int i;
2875
2876 for (i = 0; i < FNHE_HASH_SIZE; i++) {
2877 struct fib_nh_exception *fnhe;
2878
2879 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
2880 fnhe = rcu_dereference(fnhe->fnhe_next)) {
2881 struct rtable *rt;
2882 int err;
2883
2884 if (*fa_index < fa_start)
2885 goto next;
2886
2887 if (fnhe->fnhe_genid != genid)
2888 goto next;
2889
2890 if (fnhe->fnhe_expires &&
2891 time_after(jiffies, fnhe->fnhe_expires))
2892 goto next;
2893
2894 rt = rcu_dereference(fnhe->fnhe_rth_input);
2895 if (!rt)
2896 rt = rcu_dereference(fnhe->fnhe_rth_output);
2897 if (!rt)
2898 goto next;
2899
2900 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
2901 table_id, NULL, skb,
2902 NETLINK_CB(cb->skb).portid,
2903 cb->nlh->nlmsg_seq, flags);
2904 if (err)
2905 return err;
2906next:
2907 (*fa_index)++;
2908 }
2909 }
2910
2911 return 0;
2912}
2913
2914int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
2915 u32 table_id, struct fib_info *fi,
2916 int *fa_index, int fa_start, unsigned int flags)
2917{
2918 struct net *net = sock_net(cb->skb->sk);
2919 int nhsel, genid = fnhe_genid(net);
2920
2921 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
2922 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
2923 struct fnhe_hash_bucket *bucket;
2924 int err;
2925
2926 if (nhc->nhc_flags & RTNH_F_DEAD)
2927 continue;
2928
2929 rcu_read_lock();
2930 bucket = rcu_dereference(nhc->nhc_exceptions);
2931 err = 0;
2932 if (bucket)
2933 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
2934 genid, fa_index, fa_start,
2935 flags);
2936 rcu_read_unlock();
2937 if (err)
2938 return err;
2939 }
2940
2941 return 0;
2942}
2943
2944static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
2945 u8 ip_proto, __be16 sport,
2946 __be16 dport)
2947{
2948 struct sk_buff *skb;
2949 struct iphdr *iph;
2950
2951 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2952 if (!skb)
2953 return NULL;
2954
2955 /* Reserve room for dummy headers, this skb can pass
2956 * through good chunk of routing engine.
2957 */
2958 skb_reset_mac_header(skb);
2959 skb_reset_network_header(skb);
2960 skb->protocol = htons(ETH_P_IP);
2961 iph = skb_put(skb, sizeof(struct iphdr));
2962 iph->protocol = ip_proto;
2963 iph->saddr = src;
2964 iph->daddr = dst;
2965 iph->version = 0x4;
2966 iph->frag_off = 0;
2967 iph->ihl = 0x5;
2968 skb_set_transport_header(skb, skb->len);
2969
2970 switch (iph->protocol) {
2971 case IPPROTO_UDP: {
2972 struct udphdr *udph;
2973
2974 udph = skb_put_zero(skb, sizeof(struct udphdr));
2975 udph->source = sport;
2976 udph->dest = dport;
2977 udph->len = sizeof(struct udphdr);
2978 udph->check = 0;
2979 break;
2980 }
2981 case IPPROTO_TCP: {
2982 struct tcphdr *tcph;
2983
2984 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
2985 tcph->source = sport;
2986 tcph->dest = dport;
2987 tcph->doff = sizeof(struct tcphdr) / 4;
2988 tcph->rst = 1;
2989 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
2990 src, dst, 0);
2991 break;
2992 }
2993 case IPPROTO_ICMP: {
2994 struct icmphdr *icmph;
2995
2996 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
2997 icmph->type = ICMP_ECHO;
2998 icmph->code = 0;
2999 }
3000 }
3001
3002 return skb;
3003}
3004
3005static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3006 const struct nlmsghdr *nlh,
3007 struct nlattr **tb,
3008 struct netlink_ext_ack *extack)
3009{
3010 struct rtmsg *rtm;
3011 int i, err;
3012
3013 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3014 NL_SET_ERR_MSG(extack,
3015 "ipv4: Invalid header for route get request");
3016 return -EINVAL;
3017 }
3018
3019 if (!netlink_strict_get_check(skb))
3020 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3021 rtm_ipv4_policy, extack);
3022
3023 rtm = nlmsg_data(nlh);
3024 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3025 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3026 rtm->rtm_table || rtm->rtm_protocol ||
3027 rtm->rtm_scope || rtm->rtm_type) {
3028 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3029 return -EINVAL;
3030 }
3031
3032 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3033 RTM_F_LOOKUP_TABLE |
3034 RTM_F_FIB_MATCH)) {
3035 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3036 return -EINVAL;
3037 }
3038
3039 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3040 rtm_ipv4_policy, extack);
3041 if (err)
3042 return err;
3043
3044 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3045 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3046 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3047 return -EINVAL;
3048 }
3049
3050 for (i = 0; i <= RTA_MAX; i++) {
3051 if (!tb[i])
3052 continue;
3053
3054 switch (i) {
3055 case RTA_IIF:
3056 case RTA_OIF:
3057 case RTA_SRC:
3058 case RTA_DST:
3059 case RTA_IP_PROTO:
3060 case RTA_SPORT:
3061 case RTA_DPORT:
3062 case RTA_MARK:
3063 case RTA_UID:
3064 break;
3065 default:
3066 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3067 return -EINVAL;
3068 }
3069 }
3070
3071 return 0;
3072}
3073
3074static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3075 struct netlink_ext_ack *extack)
3076{
3077 struct net *net = sock_net(in_skb->sk);
3078 struct nlattr *tb[RTA_MAX+1];
3079 u32 table_id = RT_TABLE_MAIN;
3080 __be16 sport = 0, dport = 0;
3081 struct fib_result res = {};
3082 u8 ip_proto = IPPROTO_UDP;
3083 struct rtable *rt = NULL;
3084 struct sk_buff *skb;
3085 struct rtmsg *rtm;
3086 struct flowi4 fl4 = {};
3087 __be32 dst = 0;
3088 __be32 src = 0;
3089 kuid_t uid;
3090 u32 iif;
3091 int err;
3092 int mark;
3093
3094 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3095 if (err < 0)
3096 return err;
3097
3098 rtm = nlmsg_data(nlh);
3099 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3100 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3101 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3102 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3103 if (tb[RTA_UID])
3104 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3105 else
3106 uid = (iif ? INVALID_UID : current_uid());
3107
3108 if (tb[RTA_IP_PROTO]) {
3109 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3110 &ip_proto, AF_INET, extack);
3111 if (err)
3112 return err;
3113 }
3114
3115 if (tb[RTA_SPORT])
3116 sport = nla_get_be16(tb[RTA_SPORT]);
3117
3118 if (tb[RTA_DPORT])
3119 dport = nla_get_be16(tb[RTA_DPORT]);
3120
3121 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3122 if (!skb)
3123 return -ENOBUFS;
3124
3125 fl4.daddr = dst;
3126 fl4.saddr = src;
3127 fl4.flowi4_tos = rtm->rtm_tos;
3128 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3129 fl4.flowi4_mark = mark;
3130 fl4.flowi4_uid = uid;
3131 if (sport)
3132 fl4.fl4_sport = sport;
3133 if (dport)
3134 fl4.fl4_dport = dport;
3135 fl4.flowi4_proto = ip_proto;
3136
3137 rcu_read_lock();
3138
3139 if (iif) {
3140 struct net_device *dev;
3141
3142 dev = dev_get_by_index_rcu(net, iif);
3143 if (!dev) {
3144 err = -ENODEV;
3145 goto errout_rcu;
3146 }
3147
3148 fl4.flowi4_iif = iif; /* for rt_fill_info */
3149 skb->dev = dev;
3150 skb->mark = mark;
3151 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
3152 dev, &res);
3153
3154 rt = skb_rtable(skb);
3155 if (err == 0 && rt->dst.error)
3156 err = -rt->dst.error;
3157 } else {
3158 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3159 skb->dev = net->loopback_dev;
3160 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3161 err = 0;
3162 if (IS_ERR(rt))
3163 err = PTR_ERR(rt);
3164 else
3165 skb_dst_set(skb, &rt->dst);
3166 }
3167
3168 if (err)
3169 goto errout_rcu;
3170
3171 if (rtm->rtm_flags & RTM_F_NOTIFY)
3172 rt->rt_flags |= RTCF_NOTIFY;
3173
3174 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3175 table_id = res.table ? res.table->tb_id : 0;
3176
3177 /* reset skb for netlink reply msg */
3178 skb_trim(skb, 0);
3179 skb_reset_network_header(skb);
3180 skb_reset_transport_header(skb);
3181 skb_reset_mac_header(skb);
3182
3183 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3184 if (!res.fi) {
3185 err = fib_props[res.type].error;
3186 if (!err)
3187 err = -EHOSTUNREACH;
3188 goto errout_rcu;
3189 }
3190 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3191 nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
3192 rt->rt_type, res.prefix, res.prefixlen,
3193 fl4.flowi4_tos, res.fi, 0);
3194 } else {
3195 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3196 NETLINK_CB(in_skb).portid,
3197 nlh->nlmsg_seq, 0);
3198 }
3199 if (err < 0)
3200 goto errout_rcu;
3201
3202 rcu_read_unlock();
3203
3204 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3205
3206errout_free:
3207 return err;
3208errout_rcu:
3209 rcu_read_unlock();
3210 kfree_skb(skb);
3211 goto errout_free;
3212}
3213
3214void ip_rt_multicast_event(struct in_device *in_dev)
3215{
3216 rt_cache_flush(dev_net(in_dev->dev));
3217}
3218
3219#ifdef CONFIG_SYSCTL
3220static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3221static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3222static int ip_rt_gc_elasticity __read_mostly = 8;
3223static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3224
3225static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3226 void __user *buffer,
3227 size_t *lenp, loff_t *ppos)
3228{
3229 struct net *net = (struct net *)__ctl->extra1;
3230
3231 if (write) {
3232 rt_cache_flush(net);
3233 fnhe_genid_bump(net);
3234 return 0;
3235 }
3236
3237 return -EINVAL;
3238}
3239
3240static struct ctl_table ipv4_route_table[] = {
3241 {
3242 .procname = "gc_thresh",
3243 .data = &ipv4_dst_ops.gc_thresh,
3244 .maxlen = sizeof(int),
3245 .mode = 0644,
3246 .proc_handler = proc_dointvec,
3247 },
3248 {
3249 .procname = "max_size",
3250 .data = &ip_rt_max_size,
3251 .maxlen = sizeof(int),
3252 .mode = 0644,
3253 .proc_handler = proc_dointvec,
3254 },
3255 {
3256 /* Deprecated. Use gc_min_interval_ms */
3257
3258 .procname = "gc_min_interval",
3259 .data = &ip_rt_gc_min_interval,
3260 .maxlen = sizeof(int),
3261 .mode = 0644,
3262 .proc_handler = proc_dointvec_jiffies,
3263 },
3264 {
3265 .procname = "gc_min_interval_ms",
3266 .data = &ip_rt_gc_min_interval,
3267 .maxlen = sizeof(int),
3268 .mode = 0644,
3269 .proc_handler = proc_dointvec_ms_jiffies,
3270 },
3271 {
3272 .procname = "gc_timeout",
3273 .data = &ip_rt_gc_timeout,
3274 .maxlen = sizeof(int),
3275 .mode = 0644,
3276 .proc_handler = proc_dointvec_jiffies,
3277 },
3278 {
3279 .procname = "gc_interval",
3280 .data = &ip_rt_gc_interval,
3281 .maxlen = sizeof(int),
3282 .mode = 0644,
3283 .proc_handler = proc_dointvec_jiffies,
3284 },
3285 {
3286 .procname = "redirect_load",
3287 .data = &ip_rt_redirect_load,
3288 .maxlen = sizeof(int),
3289 .mode = 0644,
3290 .proc_handler = proc_dointvec,
3291 },
3292 {
3293 .procname = "redirect_number",
3294 .data = &ip_rt_redirect_number,
3295 .maxlen = sizeof(int),
3296 .mode = 0644,
3297 .proc_handler = proc_dointvec,
3298 },
3299 {
3300 .procname = "redirect_silence",
3301 .data = &ip_rt_redirect_silence,
3302 .maxlen = sizeof(int),
3303 .mode = 0644,
3304 .proc_handler = proc_dointvec,
3305 },
3306 {
3307 .procname = "error_cost",
3308 .data = &ip_rt_error_cost,
3309 .maxlen = sizeof(int),
3310 .mode = 0644,
3311 .proc_handler = proc_dointvec,
3312 },
3313 {
3314 .procname = "error_burst",
3315 .data = &ip_rt_error_burst,
3316 .maxlen = sizeof(int),
3317 .mode = 0644,
3318 .proc_handler = proc_dointvec,
3319 },
3320 {
3321 .procname = "gc_elasticity",
3322 .data = &ip_rt_gc_elasticity,
3323 .maxlen = sizeof(int),
3324 .mode = 0644,
3325 .proc_handler = proc_dointvec,
3326 },
3327 {
3328 .procname = "mtu_expires",
3329 .data = &ip_rt_mtu_expires,
3330 .maxlen = sizeof(int),
3331 .mode = 0644,
3332 .proc_handler = proc_dointvec_jiffies,
3333 },
3334 {
3335 .procname = "min_pmtu",
3336 .data = &ip_rt_min_pmtu,
3337 .maxlen = sizeof(int),
3338 .mode = 0644,
3339 .proc_handler = proc_dointvec_minmax,
3340 .extra1 = &ip_min_valid_pmtu,
3341 },
3342 {
3343 .procname = "min_adv_mss",
3344 .data = &ip_rt_min_advmss,
3345 .maxlen = sizeof(int),
3346 .mode = 0644,
3347 .proc_handler = proc_dointvec,
3348 },
3349 { }
3350};
3351
3352static const char ipv4_route_flush_procname[] = "flush";
3353
3354static struct ctl_table ipv4_route_flush_table[] = {
3355 {
3356 .procname = ipv4_route_flush_procname,
3357 .maxlen = sizeof(int),
3358 .mode = 0200,
3359 .proc_handler = ipv4_sysctl_rtcache_flush,
3360 },
3361 { },
3362};
3363
3364static __net_init int sysctl_route_net_init(struct net *net)
3365{
3366 struct ctl_table *tbl;
3367
3368 tbl = ipv4_route_flush_table;
3369 if (!net_eq(net, &init_net)) {
3370 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3371 if (!tbl)
3372 goto err_dup;
3373
3374 /* Don't export non-whitelisted sysctls to unprivileged users */
3375 if (net->user_ns != &init_user_ns) {
3376 if (tbl[0].procname != ipv4_route_flush_procname)
3377 tbl[0].procname = NULL;
3378 }
3379 }
3380 tbl[0].extra1 = net;
3381
3382 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3383 if (!net->ipv4.route_hdr)
3384 goto err_reg;
3385 return 0;
3386
3387err_reg:
3388 if (tbl != ipv4_route_flush_table)
3389 kfree(tbl);
3390err_dup:
3391 return -ENOMEM;
3392}
3393
3394static __net_exit void sysctl_route_net_exit(struct net *net)
3395{
3396 struct ctl_table *tbl;
3397
3398 tbl = net->ipv4.route_hdr->ctl_table_arg;
3399 unregister_net_sysctl_table(net->ipv4.route_hdr);
3400 BUG_ON(tbl == ipv4_route_flush_table);
3401 kfree(tbl);
3402}
3403
3404static __net_initdata struct pernet_operations sysctl_route_ops = {
3405 .init = sysctl_route_net_init,
3406 .exit = sysctl_route_net_exit,
3407};
3408#endif
3409
3410static __net_init int rt_genid_init(struct net *net)
3411{
3412 atomic_set(&net->ipv4.rt_genid, 0);
3413 atomic_set(&net->fnhe_genid, 0);
3414 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3415 return 0;
3416}
3417
3418static __net_initdata struct pernet_operations rt_genid_ops = {
3419 .init = rt_genid_init,
3420};
3421
3422static int __net_init ipv4_inetpeer_init(struct net *net)
3423{
3424 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3425
3426 if (!bp)
3427 return -ENOMEM;
3428 inet_peer_base_init(bp);
3429 net->ipv4.peers = bp;
3430 return 0;
3431}
3432
3433static void __net_exit ipv4_inetpeer_exit(struct net *net)
3434{
3435 struct inet_peer_base *bp = net->ipv4.peers;
3436
3437 net->ipv4.peers = NULL;
3438 inetpeer_invalidate_tree(bp);
3439 kfree(bp);
3440}
3441
3442static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3443 .init = ipv4_inetpeer_init,
3444 .exit = ipv4_inetpeer_exit,
3445};
3446
3447#ifdef CONFIG_IP_ROUTE_CLASSID
3448struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3449#endif /* CONFIG_IP_ROUTE_CLASSID */
3450
3451int __init ip_rt_init(void)
3452{
3453 int cpu;
3454
3455 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents),
3456 GFP_KERNEL);
3457 if (!ip_idents)
3458 panic("IP: failed to allocate ip_idents\n");
3459
3460 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3461
3462 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3463 if (!ip_tstamps)
3464 panic("IP: failed to allocate ip_tstamps\n");
3465
3466 for_each_possible_cpu(cpu) {
3467 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3468
3469 INIT_LIST_HEAD(&ul->head);
3470 spin_lock_init(&ul->lock);
3471 }
3472#ifdef CONFIG_IP_ROUTE_CLASSID
3473 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3474 if (!ip_rt_acct)
3475 panic("IP: failed to allocate ip_rt_acct\n");
3476#endif
3477
3478 ipv4_dst_ops.kmem_cachep =
3479 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3480 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3481
3482 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3483
3484 if (dst_entries_init(&ipv4_dst_ops) < 0)
3485 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3486
3487 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3488 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3489
3490 ipv4_dst_ops.gc_thresh = ~0;
3491 ip_rt_max_size = INT_MAX;
3492
3493 devinet_init();
3494 ip_fib_init();
3495
3496 if (ip_rt_proc_init())
3497 pr_err("Unable to create route proc files\n");
3498#ifdef CONFIG_XFRM
3499 xfrm_init();
3500 xfrm4_init();
3501#endif
3502 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3503 RTNL_FLAG_DOIT_UNLOCKED);
3504
3505#ifdef CONFIG_SYSCTL
3506 register_pernet_subsys(&sysctl_route_ops);
3507#endif
3508 register_pernet_subsys(&rt_genid_ops);
3509 register_pernet_subsys(&ipv4_inetpeer_ops);
3510 return 0;
3511}
3512
3513#ifdef CONFIG_SYSCTL
3514/*
3515 * We really need to sanitize the damn ipv4 init order, then all
3516 * this nonsense will go away.
3517 */
3518void __init ip_static_sysctl_init(void)
3519{
3520 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3521}
3522#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 <asm/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 <net/dst.h>
93#include <net/net_namespace.h>
94#include <net/protocol.h>
95#include <net/ip.h>
96#include <net/route.h>
97#include <net/inetpeer.h>
98#include <net/sock.h>
99#include <net/ip_fib.h>
100#include <net/arp.h>
101#include <net/tcp.h>
102#include <net/icmp.h>
103#include <net/xfrm.h>
104#include <net/netevent.h>
105#include <net/rtnetlink.h>
106#ifdef CONFIG_SYSCTL
107#include <linux/sysctl.h>
108#include <linux/kmemleak.h>
109#endif
110#include <net/secure_seq.h>
111
112#define RT_FL_TOS(oldflp4) \
113 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
114
115#define RT_GC_TIMEOUT (300*HZ)
116
117static int ip_rt_max_size;
118static int ip_rt_redirect_number __read_mostly = 9;
119static int ip_rt_redirect_load __read_mostly = HZ / 50;
120static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
121static int ip_rt_error_cost __read_mostly = HZ;
122static int ip_rt_error_burst __read_mostly = 5 * HZ;
123static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
124static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
125static int ip_rt_min_advmss __read_mostly = 256;
126
127/*
128 * Interface to generic destination cache.
129 */
130
131static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
132static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
133static unsigned int ipv4_mtu(const struct dst_entry *dst);
134static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
135static void ipv4_link_failure(struct sk_buff *skb);
136static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
137 struct sk_buff *skb, u32 mtu);
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);
151
152static struct dst_ops ipv4_dst_ops = {
153 .family = AF_INET,
154 .protocol = cpu_to_be16(ETH_P_IP),
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};
167
168#define ECN_OR_COST(class) TC_PRIO_##class
169
170const __u8 ip_tos2prio[16] = {
171 TC_PRIO_BESTEFFORT,
172 ECN_OR_COST(BESTEFFORT),
173 TC_PRIO_BESTEFFORT,
174 ECN_OR_COST(BESTEFFORT),
175 TC_PRIO_BULK,
176 ECN_OR_COST(BULK),
177 TC_PRIO_BULK,
178 ECN_OR_COST(BULK),
179 TC_PRIO_INTERACTIVE,
180 ECN_OR_COST(INTERACTIVE),
181 TC_PRIO_INTERACTIVE,
182 ECN_OR_COST(INTERACTIVE),
183 TC_PRIO_INTERACTIVE_BULK,
184 ECN_OR_COST(INTERACTIVE_BULK),
185 TC_PRIO_INTERACTIVE_BULK,
186 ECN_OR_COST(INTERACTIVE_BULK)
187};
188EXPORT_SYMBOL(ip_tos2prio);
189
190static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
191#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
192
193#ifdef CONFIG_PROC_FS
194static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
195{
196 if (*pos)
197 return NULL;
198 return SEQ_START_TOKEN;
199}
200
201static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
202{
203 ++*pos;
204 return NULL;
205}
206
207static void rt_cache_seq_stop(struct seq_file *seq, void *v)
208{
209}
210
211static int rt_cache_seq_show(struct seq_file *seq, void *v)
212{
213 if (v == SEQ_START_TOKEN)
214 seq_printf(seq, "%-127s\n",
215 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
216 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
217 "HHUptod\tSpecDst");
218 return 0;
219}
220
221static const struct seq_operations rt_cache_seq_ops = {
222 .start = rt_cache_seq_start,
223 .next = rt_cache_seq_next,
224 .stop = rt_cache_seq_stop,
225 .show = rt_cache_seq_show,
226};
227
228static int rt_cache_seq_open(struct inode *inode, struct file *file)
229{
230 return seq_open(file, &rt_cache_seq_ops);
231}
232
233static const struct file_operations rt_cache_seq_fops = {
234 .owner = THIS_MODULE,
235 .open = rt_cache_seq_open,
236 .read = seq_read,
237 .llseek = seq_lseek,
238 .release = seq_release,
239};
240
241
242static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
243{
244 int cpu;
245
246 if (*pos == 0)
247 return SEQ_START_TOKEN;
248
249 for (cpu = *pos-1; 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 return NULL;
256}
257
258static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
259{
260 int cpu;
261
262 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
263 if (!cpu_possible(cpu))
264 continue;
265 *pos = cpu+1;
266 return &per_cpu(rt_cache_stat, cpu);
267 }
268 return NULL;
269
270}
271
272static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
273{
274
275}
276
277static int rt_cpu_seq_show(struct seq_file *seq, void *v)
278{
279 struct rt_cache_stat *st = v;
280
281 if (v == SEQ_START_TOKEN) {
282 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");
283 return 0;
284 }
285
286 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
287 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
288 dst_entries_get_slow(&ipv4_dst_ops),
289 0, /* st->in_hit */
290 st->in_slow_tot,
291 st->in_slow_mc,
292 st->in_no_route,
293 st->in_brd,
294 st->in_martian_dst,
295 st->in_martian_src,
296
297 0, /* st->out_hit */
298 st->out_slow_tot,
299 st->out_slow_mc,
300
301 0, /* st->gc_total */
302 0, /* st->gc_ignored */
303 0, /* st->gc_goal_miss */
304 0, /* st->gc_dst_overflow */
305 0, /* st->in_hlist_search */
306 0 /* st->out_hlist_search */
307 );
308 return 0;
309}
310
311static const struct seq_operations rt_cpu_seq_ops = {
312 .start = rt_cpu_seq_start,
313 .next = rt_cpu_seq_next,
314 .stop = rt_cpu_seq_stop,
315 .show = rt_cpu_seq_show,
316};
317
318
319static int rt_cpu_seq_open(struct inode *inode, struct file *file)
320{
321 return seq_open(file, &rt_cpu_seq_ops);
322}
323
324static const struct file_operations rt_cpu_seq_fops = {
325 .owner = THIS_MODULE,
326 .open = rt_cpu_seq_open,
327 .read = seq_read,
328 .llseek = seq_lseek,
329 .release = seq_release,
330};
331
332#ifdef CONFIG_IP_ROUTE_CLASSID
333static int rt_acct_proc_show(struct seq_file *m, void *v)
334{
335 struct ip_rt_acct *dst, *src;
336 unsigned int i, j;
337
338 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
339 if (!dst)
340 return -ENOMEM;
341
342 for_each_possible_cpu(i) {
343 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
344 for (j = 0; j < 256; j++) {
345 dst[j].o_bytes += src[j].o_bytes;
346 dst[j].o_packets += src[j].o_packets;
347 dst[j].i_bytes += src[j].i_bytes;
348 dst[j].i_packets += src[j].i_packets;
349 }
350 }
351
352 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
353 kfree(dst);
354 return 0;
355}
356
357static int rt_acct_proc_open(struct inode *inode, struct file *file)
358{
359 return single_open(file, rt_acct_proc_show, NULL);
360}
361
362static const struct file_operations rt_acct_proc_fops = {
363 .owner = THIS_MODULE,
364 .open = rt_acct_proc_open,
365 .read = seq_read,
366 .llseek = seq_lseek,
367 .release = single_release,
368};
369#endif
370
371static int __net_init ip_rt_do_proc_init(struct net *net)
372{
373 struct proc_dir_entry *pde;
374
375 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
376 &rt_cache_seq_fops);
377 if (!pde)
378 goto err1;
379
380 pde = proc_create("rt_cache", S_IRUGO,
381 net->proc_net_stat, &rt_cpu_seq_fops);
382 if (!pde)
383 goto err2;
384
385#ifdef CONFIG_IP_ROUTE_CLASSID
386 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
387 if (!pde)
388 goto err3;
389#endif
390 return 0;
391
392#ifdef CONFIG_IP_ROUTE_CLASSID
393err3:
394 remove_proc_entry("rt_cache", net->proc_net_stat);
395#endif
396err2:
397 remove_proc_entry("rt_cache", net->proc_net);
398err1:
399 return -ENOMEM;
400}
401
402static void __net_exit ip_rt_do_proc_exit(struct net *net)
403{
404 remove_proc_entry("rt_cache", net->proc_net_stat);
405 remove_proc_entry("rt_cache", net->proc_net);
406#ifdef CONFIG_IP_ROUTE_CLASSID
407 remove_proc_entry("rt_acct", net->proc_net);
408#endif
409}
410
411static struct pernet_operations ip_rt_proc_ops __net_initdata = {
412 .init = ip_rt_do_proc_init,
413 .exit = ip_rt_do_proc_exit,
414};
415
416static int __init ip_rt_proc_init(void)
417{
418 return register_pernet_subsys(&ip_rt_proc_ops);
419}
420
421#else
422static inline int ip_rt_proc_init(void)
423{
424 return 0;
425}
426#endif /* CONFIG_PROC_FS */
427
428static inline bool rt_is_expired(const struct rtable *rth)
429{
430 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
431}
432
433void rt_cache_flush(struct net *net)
434{
435 rt_genid_bump_ipv4(net);
436}
437
438static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
439 struct sk_buff *skb,
440 const void *daddr)
441{
442 struct net_device *dev = dst->dev;
443 const __be32 *pkey = daddr;
444 const struct rtable *rt;
445 struct neighbour *n;
446
447 rt = (const struct rtable *) dst;
448 if (rt->rt_gateway)
449 pkey = (const __be32 *) &rt->rt_gateway;
450 else if (skb)
451 pkey = &ip_hdr(skb)->daddr;
452
453 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
454 if (n)
455 return n;
456 return neigh_create(&arp_tbl, pkey, dev);
457}
458
459/*
460 * Peer allocation may fail only in serious out-of-memory conditions. However
461 * we still can generate some output.
462 * Random ID selection looks a bit dangerous because we have no chances to
463 * select ID being unique in a reasonable period of time.
464 * But broken packet identifier may be better than no packet at all.
465 */
466static void ip_select_fb_ident(struct iphdr *iph)
467{
468 static DEFINE_SPINLOCK(ip_fb_id_lock);
469 static u32 ip_fallback_id;
470 u32 salt;
471
472 spin_lock_bh(&ip_fb_id_lock);
473 salt = secure_ip_id((__force __be32)ip_fallback_id ^ iph->daddr);
474 iph->id = htons(salt & 0xFFFF);
475 ip_fallback_id = salt;
476 spin_unlock_bh(&ip_fb_id_lock);
477}
478
479void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
480{
481 struct net *net = dev_net(dst->dev);
482 struct inet_peer *peer;
483
484 peer = inet_getpeer_v4(net->ipv4.peers, iph->daddr, 1);
485 if (peer) {
486 iph->id = htons(inet_getid(peer, more));
487 inet_putpeer(peer);
488 return;
489 }
490
491 ip_select_fb_ident(iph);
492}
493EXPORT_SYMBOL(__ip_select_ident);
494
495static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
496 const struct iphdr *iph,
497 int oif, u8 tos,
498 u8 prot, u32 mark, int flow_flags)
499{
500 if (sk) {
501 const struct inet_sock *inet = inet_sk(sk);
502
503 oif = sk->sk_bound_dev_if;
504 mark = sk->sk_mark;
505 tos = RT_CONN_FLAGS(sk);
506 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
507 }
508 flowi4_init_output(fl4, oif, mark, tos,
509 RT_SCOPE_UNIVERSE, prot,
510 flow_flags,
511 iph->daddr, iph->saddr, 0, 0);
512}
513
514static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
515 const struct sock *sk)
516{
517 const struct iphdr *iph = ip_hdr(skb);
518 int oif = skb->dev->ifindex;
519 u8 tos = RT_TOS(iph->tos);
520 u8 prot = iph->protocol;
521 u32 mark = skb->mark;
522
523 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
524}
525
526static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
527{
528 const struct inet_sock *inet = inet_sk(sk);
529 const struct ip_options_rcu *inet_opt;
530 __be32 daddr = inet->inet_daddr;
531
532 rcu_read_lock();
533 inet_opt = rcu_dereference(inet->inet_opt);
534 if (inet_opt && inet_opt->opt.srr)
535 daddr = inet_opt->opt.faddr;
536 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
537 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
538 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
539 inet_sk_flowi_flags(sk),
540 daddr, inet->inet_saddr, 0, 0);
541 rcu_read_unlock();
542}
543
544static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
545 const struct sk_buff *skb)
546{
547 if (skb)
548 build_skb_flow_key(fl4, skb, sk);
549 else
550 build_sk_flow_key(fl4, sk);
551}
552
553static inline void rt_free(struct rtable *rt)
554{
555 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
556}
557
558static DEFINE_SPINLOCK(fnhe_lock);
559
560static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
561{
562 struct rtable *rt;
563
564 rt = rcu_dereference(fnhe->fnhe_rth_input);
565 if (rt) {
566 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
567 rt_free(rt);
568 }
569 rt = rcu_dereference(fnhe->fnhe_rth_output);
570 if (rt) {
571 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
572 rt_free(rt);
573 }
574}
575
576static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
577{
578 struct fib_nh_exception *fnhe, *oldest;
579
580 oldest = rcu_dereference(hash->chain);
581 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
582 fnhe = rcu_dereference(fnhe->fnhe_next)) {
583 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
584 oldest = fnhe;
585 }
586 fnhe_flush_routes(oldest);
587 return oldest;
588}
589
590static inline u32 fnhe_hashfun(__be32 daddr)
591{
592 u32 hval;
593
594 hval = (__force u32) daddr;
595 hval ^= (hval >> 11) ^ (hval >> 22);
596
597 return hval & (FNHE_HASH_SIZE - 1);
598}
599
600static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
601{
602 rt->rt_pmtu = fnhe->fnhe_pmtu;
603 rt->dst.expires = fnhe->fnhe_expires;
604
605 if (fnhe->fnhe_gw) {
606 rt->rt_flags |= RTCF_REDIRECTED;
607 rt->rt_gateway = fnhe->fnhe_gw;
608 rt->rt_uses_gateway = 1;
609 }
610}
611
612static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
613 u32 pmtu, unsigned long expires)
614{
615 struct fnhe_hash_bucket *hash;
616 struct fib_nh_exception *fnhe;
617 struct rtable *rt;
618 unsigned int i;
619 int depth;
620 u32 hval = fnhe_hashfun(daddr);
621
622 spin_lock_bh(&fnhe_lock);
623
624 hash = nh->nh_exceptions;
625 if (!hash) {
626 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
627 if (!hash)
628 goto out_unlock;
629 nh->nh_exceptions = hash;
630 }
631
632 hash += hval;
633
634 depth = 0;
635 for (fnhe = rcu_dereference(hash->chain); fnhe;
636 fnhe = rcu_dereference(fnhe->fnhe_next)) {
637 if (fnhe->fnhe_daddr == daddr)
638 break;
639 depth++;
640 }
641
642 if (fnhe) {
643 if (gw)
644 fnhe->fnhe_gw = gw;
645 if (pmtu) {
646 fnhe->fnhe_pmtu = pmtu;
647 fnhe->fnhe_expires = max(1UL, expires);
648 }
649 /* Update all cached dsts too */
650 rt = rcu_dereference(fnhe->fnhe_rth_input);
651 if (rt)
652 fill_route_from_fnhe(rt, fnhe);
653 rt = rcu_dereference(fnhe->fnhe_rth_output);
654 if (rt)
655 fill_route_from_fnhe(rt, fnhe);
656 } else {
657 if (depth > FNHE_RECLAIM_DEPTH)
658 fnhe = fnhe_oldest(hash);
659 else {
660 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
661 if (!fnhe)
662 goto out_unlock;
663
664 fnhe->fnhe_next = hash->chain;
665 rcu_assign_pointer(hash->chain, fnhe);
666 }
667 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
668 fnhe->fnhe_daddr = daddr;
669 fnhe->fnhe_gw = gw;
670 fnhe->fnhe_pmtu = pmtu;
671 fnhe->fnhe_expires = expires;
672
673 /* Exception created; mark the cached routes for the nexthop
674 * stale, so anyone caching it rechecks if this exception
675 * applies to them.
676 */
677 rt = rcu_dereference(nh->nh_rth_input);
678 if (rt)
679 rt->dst.obsolete = DST_OBSOLETE_KILL;
680
681 for_each_possible_cpu(i) {
682 struct rtable __rcu **prt;
683 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
684 rt = rcu_dereference(*prt);
685 if (rt)
686 rt->dst.obsolete = DST_OBSOLETE_KILL;
687 }
688 }
689
690 fnhe->fnhe_stamp = jiffies;
691
692out_unlock:
693 spin_unlock_bh(&fnhe_lock);
694}
695
696static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
697 bool kill_route)
698{
699 __be32 new_gw = icmp_hdr(skb)->un.gateway;
700 __be32 old_gw = ip_hdr(skb)->saddr;
701 struct net_device *dev = skb->dev;
702 struct in_device *in_dev;
703 struct fib_result res;
704 struct neighbour *n;
705 struct net *net;
706
707 switch (icmp_hdr(skb)->code & 7) {
708 case ICMP_REDIR_NET:
709 case ICMP_REDIR_NETTOS:
710 case ICMP_REDIR_HOST:
711 case ICMP_REDIR_HOSTTOS:
712 break;
713
714 default:
715 return;
716 }
717
718 if (rt->rt_gateway != old_gw)
719 return;
720
721 in_dev = __in_dev_get_rcu(dev);
722 if (!in_dev)
723 return;
724
725 net = dev_net(dev);
726 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
727 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
728 ipv4_is_zeronet(new_gw))
729 goto reject_redirect;
730
731 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
732 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
733 goto reject_redirect;
734 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
735 goto reject_redirect;
736 } else {
737 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
738 goto reject_redirect;
739 }
740
741 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
742 if (n) {
743 if (!(n->nud_state & NUD_VALID)) {
744 neigh_event_send(n, NULL);
745 } else {
746 if (fib_lookup(net, fl4, &res) == 0) {
747 struct fib_nh *nh = &FIB_RES_NH(res);
748
749 update_or_create_fnhe(nh, fl4->daddr, new_gw,
750 0, 0);
751 }
752 if (kill_route)
753 rt->dst.obsolete = DST_OBSOLETE_KILL;
754 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
755 }
756 neigh_release(n);
757 }
758 return;
759
760reject_redirect:
761#ifdef CONFIG_IP_ROUTE_VERBOSE
762 if (IN_DEV_LOG_MARTIANS(in_dev)) {
763 const struct iphdr *iph = (const struct iphdr *) skb->data;
764 __be32 daddr = iph->daddr;
765 __be32 saddr = iph->saddr;
766
767 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
768 " Advised path = %pI4 -> %pI4\n",
769 &old_gw, dev->name, &new_gw,
770 &saddr, &daddr);
771 }
772#endif
773 ;
774}
775
776static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
777{
778 struct rtable *rt;
779 struct flowi4 fl4;
780 const struct iphdr *iph = (const struct iphdr *) skb->data;
781 int oif = skb->dev->ifindex;
782 u8 tos = RT_TOS(iph->tos);
783 u8 prot = iph->protocol;
784 u32 mark = skb->mark;
785
786 rt = (struct rtable *) dst;
787
788 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
789 __ip_do_redirect(rt, skb, &fl4, true);
790}
791
792static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
793{
794 struct rtable *rt = (struct rtable *)dst;
795 struct dst_entry *ret = dst;
796
797 if (rt) {
798 if (dst->obsolete > 0) {
799 ip_rt_put(rt);
800 ret = NULL;
801 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
802 rt->dst.expires) {
803 ip_rt_put(rt);
804 ret = NULL;
805 }
806 }
807 return ret;
808}
809
810/*
811 * Algorithm:
812 * 1. The first ip_rt_redirect_number redirects are sent
813 * with exponential backoff, then we stop sending them at all,
814 * assuming that the host ignores our redirects.
815 * 2. If we did not see packets requiring redirects
816 * during ip_rt_redirect_silence, we assume that the host
817 * forgot redirected route and start to send redirects again.
818 *
819 * This algorithm is much cheaper and more intelligent than dumb load limiting
820 * in icmp.c.
821 *
822 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
823 * and "frag. need" (breaks PMTU discovery) in icmp.c.
824 */
825
826void ip_rt_send_redirect(struct sk_buff *skb)
827{
828 struct rtable *rt = skb_rtable(skb);
829 struct in_device *in_dev;
830 struct inet_peer *peer;
831 struct net *net;
832 int log_martians;
833
834 rcu_read_lock();
835 in_dev = __in_dev_get_rcu(rt->dst.dev);
836 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
837 rcu_read_unlock();
838 return;
839 }
840 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
841 rcu_read_unlock();
842
843 net = dev_net(rt->dst.dev);
844 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
845 if (!peer) {
846 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
847 rt_nexthop(rt, ip_hdr(skb)->daddr));
848 return;
849 }
850
851 /* No redirected packets during ip_rt_redirect_silence;
852 * reset the algorithm.
853 */
854 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
855 peer->rate_tokens = 0;
856
857 /* Too many ignored redirects; do not send anything
858 * set dst.rate_last to the last seen redirected packet.
859 */
860 if (peer->rate_tokens >= ip_rt_redirect_number) {
861 peer->rate_last = jiffies;
862 goto out_put_peer;
863 }
864
865 /* Check for load limit; set rate_last to the latest sent
866 * redirect.
867 */
868 if (peer->rate_tokens == 0 ||
869 time_after(jiffies,
870 (peer->rate_last +
871 (ip_rt_redirect_load << peer->rate_tokens)))) {
872 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
873
874 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
875 peer->rate_last = jiffies;
876 ++peer->rate_tokens;
877#ifdef CONFIG_IP_ROUTE_VERBOSE
878 if (log_martians &&
879 peer->rate_tokens == ip_rt_redirect_number)
880 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
881 &ip_hdr(skb)->saddr, inet_iif(skb),
882 &ip_hdr(skb)->daddr, &gw);
883#endif
884 }
885out_put_peer:
886 inet_putpeer(peer);
887}
888
889static int ip_error(struct sk_buff *skb)
890{
891 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
892 struct rtable *rt = skb_rtable(skb);
893 struct inet_peer *peer;
894 unsigned long now;
895 struct net *net;
896 bool send;
897 int code;
898
899 net = dev_net(rt->dst.dev);
900 if (!IN_DEV_FORWARD(in_dev)) {
901 switch (rt->dst.error) {
902 case EHOSTUNREACH:
903 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
904 break;
905
906 case ENETUNREACH:
907 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
908 break;
909 }
910 goto out;
911 }
912
913 switch (rt->dst.error) {
914 case EINVAL:
915 default:
916 goto out;
917 case EHOSTUNREACH:
918 code = ICMP_HOST_UNREACH;
919 break;
920 case ENETUNREACH:
921 code = ICMP_NET_UNREACH;
922 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
923 break;
924 case EACCES:
925 code = ICMP_PKT_FILTERED;
926 break;
927 }
928
929 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 1);
930
931 send = true;
932 if (peer) {
933 now = jiffies;
934 peer->rate_tokens += now - peer->rate_last;
935 if (peer->rate_tokens > ip_rt_error_burst)
936 peer->rate_tokens = ip_rt_error_burst;
937 peer->rate_last = now;
938 if (peer->rate_tokens >= ip_rt_error_cost)
939 peer->rate_tokens -= ip_rt_error_cost;
940 else
941 send = false;
942 inet_putpeer(peer);
943 }
944 if (send)
945 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
946
947out: kfree_skb(skb);
948 return 0;
949}
950
951static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
952{
953 struct dst_entry *dst = &rt->dst;
954 struct fib_result res;
955
956 if (dst_metric_locked(dst, RTAX_MTU))
957 return;
958
959 if (dst->dev->mtu < mtu)
960 return;
961
962 if (mtu < ip_rt_min_pmtu)
963 mtu = ip_rt_min_pmtu;
964
965 if (rt->rt_pmtu == mtu &&
966 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
967 return;
968
969 rcu_read_lock();
970 if (fib_lookup(dev_net(dst->dev), fl4, &res) == 0) {
971 struct fib_nh *nh = &FIB_RES_NH(res);
972
973 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
974 jiffies + ip_rt_mtu_expires);
975 }
976 rcu_read_unlock();
977}
978
979static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
980 struct sk_buff *skb, u32 mtu)
981{
982 struct rtable *rt = (struct rtable *) dst;
983 struct flowi4 fl4;
984
985 ip_rt_build_flow_key(&fl4, sk, skb);
986 __ip_rt_update_pmtu(rt, &fl4, mtu);
987}
988
989void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
990 int oif, u32 mark, u8 protocol, int flow_flags)
991{
992 const struct iphdr *iph = (const struct iphdr *) skb->data;
993 struct flowi4 fl4;
994 struct rtable *rt;
995
996 __build_flow_key(&fl4, NULL, iph, oif,
997 RT_TOS(iph->tos), protocol, mark, flow_flags);
998 rt = __ip_route_output_key(net, &fl4);
999 if (!IS_ERR(rt)) {
1000 __ip_rt_update_pmtu(rt, &fl4, mtu);
1001 ip_rt_put(rt);
1002 }
1003}
1004EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1005
1006static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1007{
1008 const struct iphdr *iph = (const struct iphdr *) skb->data;
1009 struct flowi4 fl4;
1010 struct rtable *rt;
1011
1012 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1013 rt = __ip_route_output_key(sock_net(sk), &fl4);
1014 if (!IS_ERR(rt)) {
1015 __ip_rt_update_pmtu(rt, &fl4, mtu);
1016 ip_rt_put(rt);
1017 }
1018}
1019
1020void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1021{
1022 const struct iphdr *iph = (const struct iphdr *) skb->data;
1023 struct flowi4 fl4;
1024 struct rtable *rt;
1025 struct dst_entry *dst;
1026 bool new = false;
1027
1028 bh_lock_sock(sk);
1029
1030 if (!ip_sk_accept_pmtu(sk))
1031 goto out;
1032
1033 rt = (struct rtable *) __sk_dst_get(sk);
1034
1035 if (sock_owned_by_user(sk) || !rt) {
1036 __ipv4_sk_update_pmtu(skb, sk, mtu);
1037 goto out;
1038 }
1039
1040 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1041
1042 if (!__sk_dst_check(sk, 0)) {
1043 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1044 if (IS_ERR(rt))
1045 goto out;
1046
1047 new = true;
1048 }
1049
1050 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1051
1052 dst = dst_check(&rt->dst, 0);
1053 if (!dst) {
1054 if (new)
1055 dst_release(&rt->dst);
1056
1057 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1058 if (IS_ERR(rt))
1059 goto out;
1060
1061 new = true;
1062 }
1063
1064 if (new)
1065 __sk_dst_set(sk, &rt->dst);
1066
1067out:
1068 bh_unlock_sock(sk);
1069}
1070EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1071
1072void ipv4_redirect(struct sk_buff *skb, struct net *net,
1073 int oif, u32 mark, u8 protocol, int flow_flags)
1074{
1075 const struct iphdr *iph = (const struct iphdr *) skb->data;
1076 struct flowi4 fl4;
1077 struct rtable *rt;
1078
1079 __build_flow_key(&fl4, NULL, iph, oif,
1080 RT_TOS(iph->tos), protocol, mark, flow_flags);
1081 rt = __ip_route_output_key(net, &fl4);
1082 if (!IS_ERR(rt)) {
1083 __ip_do_redirect(rt, skb, &fl4, false);
1084 ip_rt_put(rt);
1085 }
1086}
1087EXPORT_SYMBOL_GPL(ipv4_redirect);
1088
1089void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1090{
1091 const struct iphdr *iph = (const struct iphdr *) skb->data;
1092 struct flowi4 fl4;
1093 struct rtable *rt;
1094
1095 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1096 rt = __ip_route_output_key(sock_net(sk), &fl4);
1097 if (!IS_ERR(rt)) {
1098 __ip_do_redirect(rt, skb, &fl4, false);
1099 ip_rt_put(rt);
1100 }
1101}
1102EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1103
1104static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1105{
1106 struct rtable *rt = (struct rtable *) dst;
1107
1108 /* All IPV4 dsts are created with ->obsolete set to the value
1109 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1110 * into this function always.
1111 *
1112 * When a PMTU/redirect information update invalidates a route,
1113 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1114 * DST_OBSOLETE_DEAD by dst_free().
1115 */
1116 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1117 return NULL;
1118 return dst;
1119}
1120
1121static void ipv4_link_failure(struct sk_buff *skb)
1122{
1123 struct rtable *rt;
1124
1125 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1126
1127 rt = skb_rtable(skb);
1128 if (rt)
1129 dst_set_expires(&rt->dst, 0);
1130}
1131
1132static int ip_rt_bug(struct sock *sk, struct sk_buff *skb)
1133{
1134 pr_debug("%s: %pI4 -> %pI4, %s\n",
1135 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1136 skb->dev ? skb->dev->name : "?");
1137 kfree_skb(skb);
1138 WARN_ON(1);
1139 return 0;
1140}
1141
1142/*
1143 We do not cache source address of outgoing interface,
1144 because it is used only by IP RR, TS and SRR options,
1145 so that it out of fast path.
1146
1147 BTW remember: "addr" is allowed to be not aligned
1148 in IP options!
1149 */
1150
1151void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1152{
1153 __be32 src;
1154
1155 if (rt_is_output_route(rt))
1156 src = ip_hdr(skb)->saddr;
1157 else {
1158 struct fib_result res;
1159 struct flowi4 fl4;
1160 struct iphdr *iph;
1161
1162 iph = ip_hdr(skb);
1163
1164 memset(&fl4, 0, sizeof(fl4));
1165 fl4.daddr = iph->daddr;
1166 fl4.saddr = iph->saddr;
1167 fl4.flowi4_tos = RT_TOS(iph->tos);
1168 fl4.flowi4_oif = rt->dst.dev->ifindex;
1169 fl4.flowi4_iif = skb->dev->ifindex;
1170 fl4.flowi4_mark = skb->mark;
1171
1172 rcu_read_lock();
1173 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0)
1174 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1175 else
1176 src = inet_select_addr(rt->dst.dev,
1177 rt_nexthop(rt, iph->daddr),
1178 RT_SCOPE_UNIVERSE);
1179 rcu_read_unlock();
1180 }
1181 memcpy(addr, &src, 4);
1182}
1183
1184#ifdef CONFIG_IP_ROUTE_CLASSID
1185static void set_class_tag(struct rtable *rt, u32 tag)
1186{
1187 if (!(rt->dst.tclassid & 0xFFFF))
1188 rt->dst.tclassid |= tag & 0xFFFF;
1189 if (!(rt->dst.tclassid & 0xFFFF0000))
1190 rt->dst.tclassid |= tag & 0xFFFF0000;
1191}
1192#endif
1193
1194static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1195{
1196 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1197
1198 if (advmss == 0) {
1199 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1200 ip_rt_min_advmss);
1201 if (advmss > 65535 - 40)
1202 advmss = 65535 - 40;
1203 }
1204 return advmss;
1205}
1206
1207static unsigned int ipv4_mtu(const struct dst_entry *dst)
1208{
1209 const struct rtable *rt = (const struct rtable *) dst;
1210 unsigned int mtu = rt->rt_pmtu;
1211
1212 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1213 mtu = dst_metric_raw(dst, RTAX_MTU);
1214
1215 if (mtu)
1216 return mtu;
1217
1218 mtu = dst->dev->mtu;
1219
1220 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1221 if (rt->rt_uses_gateway && mtu > 576)
1222 mtu = 576;
1223 }
1224
1225 return min_t(unsigned int, mtu, IP_MAX_MTU);
1226}
1227
1228static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1229{
1230 struct fnhe_hash_bucket *hash = nh->nh_exceptions;
1231 struct fib_nh_exception *fnhe;
1232 u32 hval;
1233
1234 if (!hash)
1235 return NULL;
1236
1237 hval = fnhe_hashfun(daddr);
1238
1239 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1240 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1241 if (fnhe->fnhe_daddr == daddr)
1242 return fnhe;
1243 }
1244 return NULL;
1245}
1246
1247static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1248 __be32 daddr)
1249{
1250 bool ret = false;
1251
1252 spin_lock_bh(&fnhe_lock);
1253
1254 if (daddr == fnhe->fnhe_daddr) {
1255 struct rtable __rcu **porig;
1256 struct rtable *orig;
1257 int genid = fnhe_genid(dev_net(rt->dst.dev));
1258
1259 if (rt_is_input_route(rt))
1260 porig = &fnhe->fnhe_rth_input;
1261 else
1262 porig = &fnhe->fnhe_rth_output;
1263 orig = rcu_dereference(*porig);
1264
1265 if (fnhe->fnhe_genid != genid) {
1266 fnhe->fnhe_genid = genid;
1267 fnhe->fnhe_gw = 0;
1268 fnhe->fnhe_pmtu = 0;
1269 fnhe->fnhe_expires = 0;
1270 fnhe_flush_routes(fnhe);
1271 orig = NULL;
1272 }
1273 fill_route_from_fnhe(rt, fnhe);
1274 if (!rt->rt_gateway)
1275 rt->rt_gateway = daddr;
1276
1277 if (!(rt->dst.flags & DST_NOCACHE)) {
1278 rcu_assign_pointer(*porig, rt);
1279 if (orig)
1280 rt_free(orig);
1281 ret = true;
1282 }
1283
1284 fnhe->fnhe_stamp = jiffies;
1285 }
1286 spin_unlock_bh(&fnhe_lock);
1287
1288 return ret;
1289}
1290
1291static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1292{
1293 struct rtable *orig, *prev, **p;
1294 bool ret = true;
1295
1296 if (rt_is_input_route(rt)) {
1297 p = (struct rtable **)&nh->nh_rth_input;
1298 } else {
1299 p = (struct rtable **)__this_cpu_ptr(nh->nh_pcpu_rth_output);
1300 }
1301 orig = *p;
1302
1303 prev = cmpxchg(p, orig, rt);
1304 if (prev == orig) {
1305 if (orig)
1306 rt_free(orig);
1307 } else
1308 ret = false;
1309
1310 return ret;
1311}
1312
1313static DEFINE_SPINLOCK(rt_uncached_lock);
1314static LIST_HEAD(rt_uncached_list);
1315
1316static void rt_add_uncached_list(struct rtable *rt)
1317{
1318 spin_lock_bh(&rt_uncached_lock);
1319 list_add_tail(&rt->rt_uncached, &rt_uncached_list);
1320 spin_unlock_bh(&rt_uncached_lock);
1321}
1322
1323static void ipv4_dst_destroy(struct dst_entry *dst)
1324{
1325 struct rtable *rt = (struct rtable *) dst;
1326
1327 if (!list_empty(&rt->rt_uncached)) {
1328 spin_lock_bh(&rt_uncached_lock);
1329 list_del(&rt->rt_uncached);
1330 spin_unlock_bh(&rt_uncached_lock);
1331 }
1332}
1333
1334void rt_flush_dev(struct net_device *dev)
1335{
1336 if (!list_empty(&rt_uncached_list)) {
1337 struct net *net = dev_net(dev);
1338 struct rtable *rt;
1339
1340 spin_lock_bh(&rt_uncached_lock);
1341 list_for_each_entry(rt, &rt_uncached_list, rt_uncached) {
1342 if (rt->dst.dev != dev)
1343 continue;
1344 rt->dst.dev = net->loopback_dev;
1345 dev_hold(rt->dst.dev);
1346 dev_put(dev);
1347 }
1348 spin_unlock_bh(&rt_uncached_lock);
1349 }
1350}
1351
1352static bool rt_cache_valid(const struct rtable *rt)
1353{
1354 return rt &&
1355 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1356 !rt_is_expired(rt);
1357}
1358
1359static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1360 const struct fib_result *res,
1361 struct fib_nh_exception *fnhe,
1362 struct fib_info *fi, u16 type, u32 itag)
1363{
1364 bool cached = false;
1365
1366 if (fi) {
1367 struct fib_nh *nh = &FIB_RES_NH(*res);
1368
1369 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1370 rt->rt_gateway = nh->nh_gw;
1371 rt->rt_uses_gateway = 1;
1372 }
1373 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1374#ifdef CONFIG_IP_ROUTE_CLASSID
1375 rt->dst.tclassid = nh->nh_tclassid;
1376#endif
1377 if (unlikely(fnhe))
1378 cached = rt_bind_exception(rt, fnhe, daddr);
1379 else if (!(rt->dst.flags & DST_NOCACHE))
1380 cached = rt_cache_route(nh, rt);
1381 if (unlikely(!cached)) {
1382 /* Routes we intend to cache in nexthop exception or
1383 * FIB nexthop have the DST_NOCACHE bit clear.
1384 * However, if we are unsuccessful at storing this
1385 * route into the cache we really need to set it.
1386 */
1387 rt->dst.flags |= DST_NOCACHE;
1388 if (!rt->rt_gateway)
1389 rt->rt_gateway = daddr;
1390 rt_add_uncached_list(rt);
1391 }
1392 } else
1393 rt_add_uncached_list(rt);
1394
1395#ifdef CONFIG_IP_ROUTE_CLASSID
1396#ifdef CONFIG_IP_MULTIPLE_TABLES
1397 set_class_tag(rt, res->tclassid);
1398#endif
1399 set_class_tag(rt, itag);
1400#endif
1401}
1402
1403static struct rtable *rt_dst_alloc(struct net_device *dev,
1404 bool nopolicy, bool noxfrm, bool will_cache)
1405{
1406 return dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1407 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1408 (nopolicy ? DST_NOPOLICY : 0) |
1409 (noxfrm ? DST_NOXFRM : 0));
1410}
1411
1412/* called in rcu_read_lock() section */
1413static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1414 u8 tos, struct net_device *dev, int our)
1415{
1416 struct rtable *rth;
1417 struct in_device *in_dev = __in_dev_get_rcu(dev);
1418 u32 itag = 0;
1419 int err;
1420
1421 /* Primary sanity checks. */
1422
1423 if (in_dev == NULL)
1424 return -EINVAL;
1425
1426 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1427 skb->protocol != htons(ETH_P_IP))
1428 goto e_inval;
1429
1430 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1431 if (ipv4_is_loopback(saddr))
1432 goto e_inval;
1433
1434 if (ipv4_is_zeronet(saddr)) {
1435 if (!ipv4_is_local_multicast(daddr))
1436 goto e_inval;
1437 } else {
1438 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1439 in_dev, &itag);
1440 if (err < 0)
1441 goto e_err;
1442 }
1443 rth = rt_dst_alloc(dev_net(dev)->loopback_dev,
1444 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1445 if (!rth)
1446 goto e_nobufs;
1447
1448#ifdef CONFIG_IP_ROUTE_CLASSID
1449 rth->dst.tclassid = itag;
1450#endif
1451 rth->dst.output = ip_rt_bug;
1452
1453 rth->rt_genid = rt_genid_ipv4(dev_net(dev));
1454 rth->rt_flags = RTCF_MULTICAST;
1455 rth->rt_type = RTN_MULTICAST;
1456 rth->rt_is_input= 1;
1457 rth->rt_iif = 0;
1458 rth->rt_pmtu = 0;
1459 rth->rt_gateway = 0;
1460 rth->rt_uses_gateway = 0;
1461 INIT_LIST_HEAD(&rth->rt_uncached);
1462 if (our) {
1463 rth->dst.input= ip_local_deliver;
1464 rth->rt_flags |= RTCF_LOCAL;
1465 }
1466
1467#ifdef CONFIG_IP_MROUTE
1468 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1469 rth->dst.input = ip_mr_input;
1470#endif
1471 RT_CACHE_STAT_INC(in_slow_mc);
1472
1473 skb_dst_set(skb, &rth->dst);
1474 return 0;
1475
1476e_nobufs:
1477 return -ENOBUFS;
1478e_inval:
1479 return -EINVAL;
1480e_err:
1481 return err;
1482}
1483
1484
1485static void ip_handle_martian_source(struct net_device *dev,
1486 struct in_device *in_dev,
1487 struct sk_buff *skb,
1488 __be32 daddr,
1489 __be32 saddr)
1490{
1491 RT_CACHE_STAT_INC(in_martian_src);
1492#ifdef CONFIG_IP_ROUTE_VERBOSE
1493 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1494 /*
1495 * RFC1812 recommendation, if source is martian,
1496 * the only hint is MAC header.
1497 */
1498 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1499 &daddr, &saddr, dev->name);
1500 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1501 print_hex_dump(KERN_WARNING, "ll header: ",
1502 DUMP_PREFIX_OFFSET, 16, 1,
1503 skb_mac_header(skb),
1504 dev->hard_header_len, true);
1505 }
1506 }
1507#endif
1508}
1509
1510/* called in rcu_read_lock() section */
1511static int __mkroute_input(struct sk_buff *skb,
1512 const struct fib_result *res,
1513 struct in_device *in_dev,
1514 __be32 daddr, __be32 saddr, u32 tos)
1515{
1516 struct fib_nh_exception *fnhe;
1517 struct rtable *rth;
1518 int err;
1519 struct in_device *out_dev;
1520 unsigned int flags = 0;
1521 bool do_cache;
1522 u32 itag = 0;
1523
1524 /* get a working reference to the output device */
1525 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1526 if (out_dev == NULL) {
1527 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1528 return -EINVAL;
1529 }
1530
1531 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1532 in_dev->dev, in_dev, &itag);
1533 if (err < 0) {
1534 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1535 saddr);
1536
1537 goto cleanup;
1538 }
1539
1540 do_cache = res->fi && !itag;
1541 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1542 (IN_DEV_SHARED_MEDIA(out_dev) ||
1543 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) {
1544 flags |= RTCF_DOREDIRECT;
1545 do_cache = false;
1546 }
1547
1548 if (skb->protocol != htons(ETH_P_IP)) {
1549 /* Not IP (i.e. ARP). Do not create route, if it is
1550 * invalid for proxy arp. DNAT routes are always valid.
1551 *
1552 * Proxy arp feature have been extended to allow, ARP
1553 * replies back to the same interface, to support
1554 * Private VLAN switch technologies. See arp.c.
1555 */
1556 if (out_dev == in_dev &&
1557 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1558 err = -EINVAL;
1559 goto cleanup;
1560 }
1561 }
1562
1563 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1564 if (do_cache) {
1565 if (fnhe != NULL)
1566 rth = rcu_dereference(fnhe->fnhe_rth_input);
1567 else
1568 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1569
1570 if (rt_cache_valid(rth)) {
1571 skb_dst_set_noref(skb, &rth->dst);
1572 goto out;
1573 }
1574 }
1575
1576 rth = rt_dst_alloc(out_dev->dev,
1577 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1578 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1579 if (!rth) {
1580 err = -ENOBUFS;
1581 goto cleanup;
1582 }
1583
1584 rth->rt_genid = rt_genid_ipv4(dev_net(rth->dst.dev));
1585 rth->rt_flags = flags;
1586 rth->rt_type = res->type;
1587 rth->rt_is_input = 1;
1588 rth->rt_iif = 0;
1589 rth->rt_pmtu = 0;
1590 rth->rt_gateway = 0;
1591 rth->rt_uses_gateway = 0;
1592 INIT_LIST_HEAD(&rth->rt_uncached);
1593 RT_CACHE_STAT_INC(in_slow_tot);
1594
1595 rth->dst.input = ip_forward;
1596 rth->dst.output = ip_output;
1597
1598 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1599 skb_dst_set(skb, &rth->dst);
1600out:
1601 err = 0;
1602 cleanup:
1603 return err;
1604}
1605
1606static int ip_mkroute_input(struct sk_buff *skb,
1607 struct fib_result *res,
1608 const struct flowi4 *fl4,
1609 struct in_device *in_dev,
1610 __be32 daddr, __be32 saddr, u32 tos)
1611{
1612#ifdef CONFIG_IP_ROUTE_MULTIPATH
1613 if (res->fi && res->fi->fib_nhs > 1)
1614 fib_select_multipath(res);
1615#endif
1616
1617 /* create a routing cache entry */
1618 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1619}
1620
1621/*
1622 * NOTE. We drop all the packets that has local source
1623 * addresses, because every properly looped back packet
1624 * must have correct destination already attached by output routine.
1625 *
1626 * Such approach solves two big problems:
1627 * 1. Not simplex devices are handled properly.
1628 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1629 * called with rcu_read_lock()
1630 */
1631
1632static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1633 u8 tos, struct net_device *dev)
1634{
1635 struct fib_result res;
1636 struct in_device *in_dev = __in_dev_get_rcu(dev);
1637 struct flowi4 fl4;
1638 unsigned int flags = 0;
1639 u32 itag = 0;
1640 struct rtable *rth;
1641 int err = -EINVAL;
1642 struct net *net = dev_net(dev);
1643 bool do_cache;
1644
1645 /* IP on this device is disabled. */
1646
1647 if (!in_dev)
1648 goto out;
1649
1650 /* Check for the most weird martians, which can be not detected
1651 by fib_lookup.
1652 */
1653
1654 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1655 goto martian_source;
1656
1657 res.fi = NULL;
1658 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1659 goto brd_input;
1660
1661 /* Accept zero addresses only to limited broadcast;
1662 * I even do not know to fix it or not. Waiting for complains :-)
1663 */
1664 if (ipv4_is_zeronet(saddr))
1665 goto martian_source;
1666
1667 if (ipv4_is_zeronet(daddr))
1668 goto martian_destination;
1669
1670 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1671 * and call it once if daddr or/and saddr are loopback addresses
1672 */
1673 if (ipv4_is_loopback(daddr)) {
1674 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1675 goto martian_destination;
1676 } else if (ipv4_is_loopback(saddr)) {
1677 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1678 goto martian_source;
1679 }
1680
1681 /*
1682 * Now we are ready to route packet.
1683 */
1684 fl4.flowi4_oif = 0;
1685 fl4.flowi4_iif = dev->ifindex;
1686 fl4.flowi4_mark = skb->mark;
1687 fl4.flowi4_tos = tos;
1688 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1689 fl4.daddr = daddr;
1690 fl4.saddr = saddr;
1691 err = fib_lookup(net, &fl4, &res);
1692 if (err != 0) {
1693 if (!IN_DEV_FORWARD(in_dev))
1694 err = -EHOSTUNREACH;
1695 goto no_route;
1696 }
1697
1698 if (res.type == RTN_BROADCAST)
1699 goto brd_input;
1700
1701 if (res.type == RTN_LOCAL) {
1702 err = fib_validate_source(skb, saddr, daddr, tos,
1703 0, dev, in_dev, &itag);
1704 if (err < 0)
1705 goto martian_source_keep_err;
1706 goto local_input;
1707 }
1708
1709 if (!IN_DEV_FORWARD(in_dev)) {
1710 err = -EHOSTUNREACH;
1711 goto no_route;
1712 }
1713 if (res.type != RTN_UNICAST)
1714 goto martian_destination;
1715
1716 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1717out: return err;
1718
1719brd_input:
1720 if (skb->protocol != htons(ETH_P_IP))
1721 goto e_inval;
1722
1723 if (!ipv4_is_zeronet(saddr)) {
1724 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1725 in_dev, &itag);
1726 if (err < 0)
1727 goto martian_source_keep_err;
1728 }
1729 flags |= RTCF_BROADCAST;
1730 res.type = RTN_BROADCAST;
1731 RT_CACHE_STAT_INC(in_brd);
1732
1733local_input:
1734 do_cache = false;
1735 if (res.fi) {
1736 if (!itag) {
1737 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1738 if (rt_cache_valid(rth)) {
1739 skb_dst_set_noref(skb, &rth->dst);
1740 err = 0;
1741 goto out;
1742 }
1743 do_cache = true;
1744 }
1745 }
1746
1747 rth = rt_dst_alloc(net->loopback_dev,
1748 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1749 if (!rth)
1750 goto e_nobufs;
1751
1752 rth->dst.input= ip_local_deliver;
1753 rth->dst.output= ip_rt_bug;
1754#ifdef CONFIG_IP_ROUTE_CLASSID
1755 rth->dst.tclassid = itag;
1756#endif
1757
1758 rth->rt_genid = rt_genid_ipv4(net);
1759 rth->rt_flags = flags|RTCF_LOCAL;
1760 rth->rt_type = res.type;
1761 rth->rt_is_input = 1;
1762 rth->rt_iif = 0;
1763 rth->rt_pmtu = 0;
1764 rth->rt_gateway = 0;
1765 rth->rt_uses_gateway = 0;
1766 INIT_LIST_HEAD(&rth->rt_uncached);
1767 RT_CACHE_STAT_INC(in_slow_tot);
1768 if (res.type == RTN_UNREACHABLE) {
1769 rth->dst.input= ip_error;
1770 rth->dst.error= -err;
1771 rth->rt_flags &= ~RTCF_LOCAL;
1772 }
1773 if (do_cache) {
1774 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
1775 rth->dst.flags |= DST_NOCACHE;
1776 rt_add_uncached_list(rth);
1777 }
1778 }
1779 skb_dst_set(skb, &rth->dst);
1780 err = 0;
1781 goto out;
1782
1783no_route:
1784 RT_CACHE_STAT_INC(in_no_route);
1785 res.type = RTN_UNREACHABLE;
1786 if (err == -ESRCH)
1787 err = -ENETUNREACH;
1788 goto local_input;
1789
1790 /*
1791 * Do not cache martian addresses: they should be logged (RFC1812)
1792 */
1793martian_destination:
1794 RT_CACHE_STAT_INC(in_martian_dst);
1795#ifdef CONFIG_IP_ROUTE_VERBOSE
1796 if (IN_DEV_LOG_MARTIANS(in_dev))
1797 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1798 &daddr, &saddr, dev->name);
1799#endif
1800
1801e_inval:
1802 err = -EINVAL;
1803 goto out;
1804
1805e_nobufs:
1806 err = -ENOBUFS;
1807 goto out;
1808
1809martian_source:
1810 err = -EINVAL;
1811martian_source_keep_err:
1812 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1813 goto out;
1814}
1815
1816int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1817 u8 tos, struct net_device *dev)
1818{
1819 int res;
1820
1821 rcu_read_lock();
1822
1823 /* Multicast recognition logic is moved from route cache to here.
1824 The problem was that too many Ethernet cards have broken/missing
1825 hardware multicast filters :-( As result the host on multicasting
1826 network acquires a lot of useless route cache entries, sort of
1827 SDR messages from all the world. Now we try to get rid of them.
1828 Really, provided software IP multicast filter is organized
1829 reasonably (at least, hashed), it does not result in a slowdown
1830 comparing with route cache reject entries.
1831 Note, that multicast routers are not affected, because
1832 route cache entry is created eventually.
1833 */
1834 if (ipv4_is_multicast(daddr)) {
1835 struct in_device *in_dev = __in_dev_get_rcu(dev);
1836
1837 if (in_dev) {
1838 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1839 ip_hdr(skb)->protocol);
1840 if (our
1841#ifdef CONFIG_IP_MROUTE
1842 ||
1843 (!ipv4_is_local_multicast(daddr) &&
1844 IN_DEV_MFORWARD(in_dev))
1845#endif
1846 ) {
1847 int res = ip_route_input_mc(skb, daddr, saddr,
1848 tos, dev, our);
1849 rcu_read_unlock();
1850 return res;
1851 }
1852 }
1853 rcu_read_unlock();
1854 return -EINVAL;
1855 }
1856 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1857 rcu_read_unlock();
1858 return res;
1859}
1860EXPORT_SYMBOL(ip_route_input_noref);
1861
1862/* called with rcu_read_lock() */
1863static struct rtable *__mkroute_output(const struct fib_result *res,
1864 const struct flowi4 *fl4, int orig_oif,
1865 struct net_device *dev_out,
1866 unsigned int flags)
1867{
1868 struct fib_info *fi = res->fi;
1869 struct fib_nh_exception *fnhe;
1870 struct in_device *in_dev;
1871 u16 type = res->type;
1872 struct rtable *rth;
1873 bool do_cache;
1874
1875 in_dev = __in_dev_get_rcu(dev_out);
1876 if (!in_dev)
1877 return ERR_PTR(-EINVAL);
1878
1879 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
1880 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
1881 return ERR_PTR(-EINVAL);
1882
1883 if (ipv4_is_lbcast(fl4->daddr))
1884 type = RTN_BROADCAST;
1885 else if (ipv4_is_multicast(fl4->daddr))
1886 type = RTN_MULTICAST;
1887 else if (ipv4_is_zeronet(fl4->daddr))
1888 return ERR_PTR(-EINVAL);
1889
1890 if (dev_out->flags & IFF_LOOPBACK)
1891 flags |= RTCF_LOCAL;
1892
1893 do_cache = true;
1894 if (type == RTN_BROADCAST) {
1895 flags |= RTCF_BROADCAST | RTCF_LOCAL;
1896 fi = NULL;
1897 } else if (type == RTN_MULTICAST) {
1898 flags |= RTCF_MULTICAST | RTCF_LOCAL;
1899 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
1900 fl4->flowi4_proto))
1901 flags &= ~RTCF_LOCAL;
1902 else
1903 do_cache = false;
1904 /* If multicast route do not exist use
1905 * default one, but do not gateway in this case.
1906 * Yes, it is hack.
1907 */
1908 if (fi && res->prefixlen < 4)
1909 fi = NULL;
1910 }
1911
1912 fnhe = NULL;
1913 do_cache &= fi != NULL;
1914 if (do_cache) {
1915 struct rtable __rcu **prth;
1916 struct fib_nh *nh = &FIB_RES_NH(*res);
1917
1918 fnhe = find_exception(nh, fl4->daddr);
1919 if (fnhe)
1920 prth = &fnhe->fnhe_rth_output;
1921 else {
1922 if (unlikely(fl4->flowi4_flags &
1923 FLOWI_FLAG_KNOWN_NH &&
1924 !(nh->nh_gw &&
1925 nh->nh_scope == RT_SCOPE_LINK))) {
1926 do_cache = false;
1927 goto add;
1928 }
1929 prth = __this_cpu_ptr(nh->nh_pcpu_rth_output);
1930 }
1931 rth = rcu_dereference(*prth);
1932 if (rt_cache_valid(rth)) {
1933 dst_hold(&rth->dst);
1934 return rth;
1935 }
1936 }
1937
1938add:
1939 rth = rt_dst_alloc(dev_out,
1940 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1941 IN_DEV_CONF_GET(in_dev, NOXFRM),
1942 do_cache);
1943 if (!rth)
1944 return ERR_PTR(-ENOBUFS);
1945
1946 rth->dst.output = ip_output;
1947
1948 rth->rt_genid = rt_genid_ipv4(dev_net(dev_out));
1949 rth->rt_flags = flags;
1950 rth->rt_type = type;
1951 rth->rt_is_input = 0;
1952 rth->rt_iif = orig_oif ? : 0;
1953 rth->rt_pmtu = 0;
1954 rth->rt_gateway = 0;
1955 rth->rt_uses_gateway = 0;
1956 INIT_LIST_HEAD(&rth->rt_uncached);
1957
1958 RT_CACHE_STAT_INC(out_slow_tot);
1959
1960 if (flags & RTCF_LOCAL)
1961 rth->dst.input = ip_local_deliver;
1962 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
1963 if (flags & RTCF_LOCAL &&
1964 !(dev_out->flags & IFF_LOOPBACK)) {
1965 rth->dst.output = ip_mc_output;
1966 RT_CACHE_STAT_INC(out_slow_mc);
1967 }
1968#ifdef CONFIG_IP_MROUTE
1969 if (type == RTN_MULTICAST) {
1970 if (IN_DEV_MFORWARD(in_dev) &&
1971 !ipv4_is_local_multicast(fl4->daddr)) {
1972 rth->dst.input = ip_mr_input;
1973 rth->dst.output = ip_mc_output;
1974 }
1975 }
1976#endif
1977 }
1978
1979 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
1980
1981 return rth;
1982}
1983
1984/*
1985 * Major route resolver routine.
1986 */
1987
1988struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4)
1989{
1990 struct net_device *dev_out = NULL;
1991 __u8 tos = RT_FL_TOS(fl4);
1992 unsigned int flags = 0;
1993 struct fib_result res;
1994 struct rtable *rth;
1995 int orig_oif;
1996
1997 res.tclassid = 0;
1998 res.fi = NULL;
1999 res.table = NULL;
2000
2001 orig_oif = fl4->flowi4_oif;
2002
2003 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2004 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2005 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2006 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2007
2008 rcu_read_lock();
2009 if (fl4->saddr) {
2010 rth = ERR_PTR(-EINVAL);
2011 if (ipv4_is_multicast(fl4->saddr) ||
2012 ipv4_is_lbcast(fl4->saddr) ||
2013 ipv4_is_zeronet(fl4->saddr))
2014 goto out;
2015
2016 /* I removed check for oif == dev_out->oif here.
2017 It was wrong for two reasons:
2018 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2019 is assigned to multiple interfaces.
2020 2. Moreover, we are allowed to send packets with saddr
2021 of another iface. --ANK
2022 */
2023
2024 if (fl4->flowi4_oif == 0 &&
2025 (ipv4_is_multicast(fl4->daddr) ||
2026 ipv4_is_lbcast(fl4->daddr))) {
2027 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2028 dev_out = __ip_dev_find(net, fl4->saddr, false);
2029 if (dev_out == NULL)
2030 goto out;
2031
2032 /* Special hack: user can direct multicasts
2033 and limited broadcast via necessary interface
2034 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2035 This hack is not just for fun, it allows
2036 vic,vat and friends to work.
2037 They bind socket to loopback, set ttl to zero
2038 and expect that it will work.
2039 From the viewpoint of routing cache they are broken,
2040 because we are not allowed to build multicast path
2041 with loopback source addr (look, routing cache
2042 cannot know, that ttl is zero, so that packet
2043 will not leave this host and route is valid).
2044 Luckily, this hack is good workaround.
2045 */
2046
2047 fl4->flowi4_oif = dev_out->ifindex;
2048 goto make_route;
2049 }
2050
2051 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2052 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2053 if (!__ip_dev_find(net, fl4->saddr, false))
2054 goto out;
2055 }
2056 }
2057
2058
2059 if (fl4->flowi4_oif) {
2060 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2061 rth = ERR_PTR(-ENODEV);
2062 if (dev_out == NULL)
2063 goto out;
2064
2065 /* RACE: Check return value of inet_select_addr instead. */
2066 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2067 rth = ERR_PTR(-ENETUNREACH);
2068 goto out;
2069 }
2070 if (ipv4_is_local_multicast(fl4->daddr) ||
2071 ipv4_is_lbcast(fl4->daddr)) {
2072 if (!fl4->saddr)
2073 fl4->saddr = inet_select_addr(dev_out, 0,
2074 RT_SCOPE_LINK);
2075 goto make_route;
2076 }
2077 if (!fl4->saddr) {
2078 if (ipv4_is_multicast(fl4->daddr))
2079 fl4->saddr = inet_select_addr(dev_out, 0,
2080 fl4->flowi4_scope);
2081 else if (!fl4->daddr)
2082 fl4->saddr = inet_select_addr(dev_out, 0,
2083 RT_SCOPE_HOST);
2084 }
2085 }
2086
2087 if (!fl4->daddr) {
2088 fl4->daddr = fl4->saddr;
2089 if (!fl4->daddr)
2090 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2091 dev_out = net->loopback_dev;
2092 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2093 res.type = RTN_LOCAL;
2094 flags |= RTCF_LOCAL;
2095 goto make_route;
2096 }
2097
2098 if (fib_lookup(net, fl4, &res)) {
2099 res.fi = NULL;
2100 res.table = NULL;
2101 if (fl4->flowi4_oif) {
2102 /* Apparently, routing tables are wrong. Assume,
2103 that the destination is on link.
2104
2105 WHY? DW.
2106 Because we are allowed to send to iface
2107 even if it has NO routes and NO assigned
2108 addresses. When oif is specified, routing
2109 tables are looked up with only one purpose:
2110 to catch if destination is gatewayed, rather than
2111 direct. Moreover, if MSG_DONTROUTE is set,
2112 we send packet, ignoring both routing tables
2113 and ifaddr state. --ANK
2114
2115
2116 We could make it even if oif is unknown,
2117 likely IPv6, but we do not.
2118 */
2119
2120 if (fl4->saddr == 0)
2121 fl4->saddr = inet_select_addr(dev_out, 0,
2122 RT_SCOPE_LINK);
2123 res.type = RTN_UNICAST;
2124 goto make_route;
2125 }
2126 rth = ERR_PTR(-ENETUNREACH);
2127 goto out;
2128 }
2129
2130 if (res.type == RTN_LOCAL) {
2131 if (!fl4->saddr) {
2132 if (res.fi->fib_prefsrc)
2133 fl4->saddr = res.fi->fib_prefsrc;
2134 else
2135 fl4->saddr = fl4->daddr;
2136 }
2137 dev_out = net->loopback_dev;
2138 fl4->flowi4_oif = dev_out->ifindex;
2139 flags |= RTCF_LOCAL;
2140 goto make_route;
2141 }
2142
2143#ifdef CONFIG_IP_ROUTE_MULTIPATH
2144 if (res.fi->fib_nhs > 1 && fl4->flowi4_oif == 0)
2145 fib_select_multipath(&res);
2146 else
2147#endif
2148 if (!res.prefixlen &&
2149 res.table->tb_num_default > 1 &&
2150 res.type == RTN_UNICAST && !fl4->flowi4_oif)
2151 fib_select_default(&res);
2152
2153 if (!fl4->saddr)
2154 fl4->saddr = FIB_RES_PREFSRC(net, res);
2155
2156 dev_out = FIB_RES_DEV(res);
2157 fl4->flowi4_oif = dev_out->ifindex;
2158
2159
2160make_route:
2161 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2162
2163out:
2164 rcu_read_unlock();
2165 return rth;
2166}
2167EXPORT_SYMBOL_GPL(__ip_route_output_key);
2168
2169static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2170{
2171 return NULL;
2172}
2173
2174static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2175{
2176 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2177
2178 return mtu ? : dst->dev->mtu;
2179}
2180
2181static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2182 struct sk_buff *skb, u32 mtu)
2183{
2184}
2185
2186static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2187 struct sk_buff *skb)
2188{
2189}
2190
2191static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2192 unsigned long old)
2193{
2194 return NULL;
2195}
2196
2197static struct dst_ops ipv4_dst_blackhole_ops = {
2198 .family = AF_INET,
2199 .protocol = cpu_to_be16(ETH_P_IP),
2200 .check = ipv4_blackhole_dst_check,
2201 .mtu = ipv4_blackhole_mtu,
2202 .default_advmss = ipv4_default_advmss,
2203 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2204 .redirect = ipv4_rt_blackhole_redirect,
2205 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2206 .neigh_lookup = ipv4_neigh_lookup,
2207};
2208
2209struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2210{
2211 struct rtable *ort = (struct rtable *) dst_orig;
2212 struct rtable *rt;
2213
2214 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2215 if (rt) {
2216 struct dst_entry *new = &rt->dst;
2217
2218 new->__use = 1;
2219 new->input = dst_discard;
2220 new->output = dst_discard_sk;
2221
2222 new->dev = ort->dst.dev;
2223 if (new->dev)
2224 dev_hold(new->dev);
2225
2226 rt->rt_is_input = ort->rt_is_input;
2227 rt->rt_iif = ort->rt_iif;
2228 rt->rt_pmtu = ort->rt_pmtu;
2229
2230 rt->rt_genid = rt_genid_ipv4(net);
2231 rt->rt_flags = ort->rt_flags;
2232 rt->rt_type = ort->rt_type;
2233 rt->rt_gateway = ort->rt_gateway;
2234 rt->rt_uses_gateway = ort->rt_uses_gateway;
2235
2236 INIT_LIST_HEAD(&rt->rt_uncached);
2237
2238 dst_free(new);
2239 }
2240
2241 dst_release(dst_orig);
2242
2243 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2244}
2245
2246struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2247 struct sock *sk)
2248{
2249 struct rtable *rt = __ip_route_output_key(net, flp4);
2250
2251 if (IS_ERR(rt))
2252 return rt;
2253
2254 if (flp4->flowi4_proto)
2255 rt = (struct rtable *) xfrm_lookup(net, &rt->dst,
2256 flowi4_to_flowi(flp4),
2257 sk, 0);
2258
2259 return rt;
2260}
2261EXPORT_SYMBOL_GPL(ip_route_output_flow);
2262
2263static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2264 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2265 u32 seq, int event, int nowait, unsigned int flags)
2266{
2267 struct rtable *rt = skb_rtable(skb);
2268 struct rtmsg *r;
2269 struct nlmsghdr *nlh;
2270 unsigned long expires = 0;
2271 u32 error;
2272 u32 metrics[RTAX_MAX];
2273
2274 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2275 if (nlh == NULL)
2276 return -EMSGSIZE;
2277
2278 r = nlmsg_data(nlh);
2279 r->rtm_family = AF_INET;
2280 r->rtm_dst_len = 32;
2281 r->rtm_src_len = 0;
2282 r->rtm_tos = fl4->flowi4_tos;
2283 r->rtm_table = RT_TABLE_MAIN;
2284 if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN))
2285 goto nla_put_failure;
2286 r->rtm_type = rt->rt_type;
2287 r->rtm_scope = RT_SCOPE_UNIVERSE;
2288 r->rtm_protocol = RTPROT_UNSPEC;
2289 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2290 if (rt->rt_flags & RTCF_NOTIFY)
2291 r->rtm_flags |= RTM_F_NOTIFY;
2292
2293 if (nla_put_be32(skb, RTA_DST, dst))
2294 goto nla_put_failure;
2295 if (src) {
2296 r->rtm_src_len = 32;
2297 if (nla_put_be32(skb, RTA_SRC, src))
2298 goto nla_put_failure;
2299 }
2300 if (rt->dst.dev &&
2301 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2302 goto nla_put_failure;
2303#ifdef CONFIG_IP_ROUTE_CLASSID
2304 if (rt->dst.tclassid &&
2305 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2306 goto nla_put_failure;
2307#endif
2308 if (!rt_is_input_route(rt) &&
2309 fl4->saddr != src) {
2310 if (nla_put_be32(skb, RTA_PREFSRC, fl4->saddr))
2311 goto nla_put_failure;
2312 }
2313 if (rt->rt_uses_gateway &&
2314 nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))
2315 goto nla_put_failure;
2316
2317 expires = rt->dst.expires;
2318 if (expires) {
2319 unsigned long now = jiffies;
2320
2321 if (time_before(now, expires))
2322 expires -= now;
2323 else
2324 expires = 0;
2325 }
2326
2327 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2328 if (rt->rt_pmtu && expires)
2329 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2330 if (rtnetlink_put_metrics(skb, metrics) < 0)
2331 goto nla_put_failure;
2332
2333 if (fl4->flowi4_mark &&
2334 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2335 goto nla_put_failure;
2336
2337 error = rt->dst.error;
2338
2339 if (rt_is_input_route(rt)) {
2340#ifdef CONFIG_IP_MROUTE
2341 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2342 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2343 int err = ipmr_get_route(net, skb,
2344 fl4->saddr, fl4->daddr,
2345 r, nowait);
2346 if (err <= 0) {
2347 if (!nowait) {
2348 if (err == 0)
2349 return 0;
2350 goto nla_put_failure;
2351 } else {
2352 if (err == -EMSGSIZE)
2353 goto nla_put_failure;
2354 error = err;
2355 }
2356 }
2357 } else
2358#endif
2359 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2360 goto nla_put_failure;
2361 }
2362
2363 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2364 goto nla_put_failure;
2365
2366 return nlmsg_end(skb, nlh);
2367
2368nla_put_failure:
2369 nlmsg_cancel(skb, nlh);
2370 return -EMSGSIZE;
2371}
2372
2373static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2374{
2375 struct net *net = sock_net(in_skb->sk);
2376 struct rtmsg *rtm;
2377 struct nlattr *tb[RTA_MAX+1];
2378 struct rtable *rt = NULL;
2379 struct flowi4 fl4;
2380 __be32 dst = 0;
2381 __be32 src = 0;
2382 u32 iif;
2383 int err;
2384 int mark;
2385 struct sk_buff *skb;
2386
2387 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2388 if (err < 0)
2389 goto errout;
2390
2391 rtm = nlmsg_data(nlh);
2392
2393 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2394 if (skb == NULL) {
2395 err = -ENOBUFS;
2396 goto errout;
2397 }
2398
2399 /* Reserve room for dummy headers, this skb can pass
2400 through good chunk of routing engine.
2401 */
2402 skb_reset_mac_header(skb);
2403 skb_reset_network_header(skb);
2404
2405 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2406 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2407 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2408
2409 src = tb[RTA_SRC] ? nla_get_be32(tb[RTA_SRC]) : 0;
2410 dst = tb[RTA_DST] ? nla_get_be32(tb[RTA_DST]) : 0;
2411 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2412 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2413
2414 memset(&fl4, 0, sizeof(fl4));
2415 fl4.daddr = dst;
2416 fl4.saddr = src;
2417 fl4.flowi4_tos = rtm->rtm_tos;
2418 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2419 fl4.flowi4_mark = mark;
2420
2421 if (iif) {
2422 struct net_device *dev;
2423
2424 dev = __dev_get_by_index(net, iif);
2425 if (dev == NULL) {
2426 err = -ENODEV;
2427 goto errout_free;
2428 }
2429
2430 skb->protocol = htons(ETH_P_IP);
2431 skb->dev = dev;
2432 skb->mark = mark;
2433 local_bh_disable();
2434 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2435 local_bh_enable();
2436
2437 rt = skb_rtable(skb);
2438 if (err == 0 && rt->dst.error)
2439 err = -rt->dst.error;
2440 } else {
2441 rt = ip_route_output_key(net, &fl4);
2442
2443 err = 0;
2444 if (IS_ERR(rt))
2445 err = PTR_ERR(rt);
2446 }
2447
2448 if (err)
2449 goto errout_free;
2450
2451 skb_dst_set(skb, &rt->dst);
2452 if (rtm->rtm_flags & RTM_F_NOTIFY)
2453 rt->rt_flags |= RTCF_NOTIFY;
2454
2455 err = rt_fill_info(net, dst, src, &fl4, skb,
2456 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2457 RTM_NEWROUTE, 0, 0);
2458 if (err <= 0)
2459 goto errout_free;
2460
2461 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2462errout:
2463 return err;
2464
2465errout_free:
2466 kfree_skb(skb);
2467 goto errout;
2468}
2469
2470void ip_rt_multicast_event(struct in_device *in_dev)
2471{
2472 rt_cache_flush(dev_net(in_dev->dev));
2473}
2474
2475#ifdef CONFIG_SYSCTL
2476static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
2477static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2478static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2479static int ip_rt_gc_elasticity __read_mostly = 8;
2480
2481static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2482 void __user *buffer,
2483 size_t *lenp, loff_t *ppos)
2484{
2485 struct net *net = (struct net *)__ctl->extra1;
2486
2487 if (write) {
2488 rt_cache_flush(net);
2489 fnhe_genid_bump(net);
2490 return 0;
2491 }
2492
2493 return -EINVAL;
2494}
2495
2496static struct ctl_table ipv4_route_table[] = {
2497 {
2498 .procname = "gc_thresh",
2499 .data = &ipv4_dst_ops.gc_thresh,
2500 .maxlen = sizeof(int),
2501 .mode = 0644,
2502 .proc_handler = proc_dointvec,
2503 },
2504 {
2505 .procname = "max_size",
2506 .data = &ip_rt_max_size,
2507 .maxlen = sizeof(int),
2508 .mode = 0644,
2509 .proc_handler = proc_dointvec,
2510 },
2511 {
2512 /* Deprecated. Use gc_min_interval_ms */
2513
2514 .procname = "gc_min_interval",
2515 .data = &ip_rt_gc_min_interval,
2516 .maxlen = sizeof(int),
2517 .mode = 0644,
2518 .proc_handler = proc_dointvec_jiffies,
2519 },
2520 {
2521 .procname = "gc_min_interval_ms",
2522 .data = &ip_rt_gc_min_interval,
2523 .maxlen = sizeof(int),
2524 .mode = 0644,
2525 .proc_handler = proc_dointvec_ms_jiffies,
2526 },
2527 {
2528 .procname = "gc_timeout",
2529 .data = &ip_rt_gc_timeout,
2530 .maxlen = sizeof(int),
2531 .mode = 0644,
2532 .proc_handler = proc_dointvec_jiffies,
2533 },
2534 {
2535 .procname = "gc_interval",
2536 .data = &ip_rt_gc_interval,
2537 .maxlen = sizeof(int),
2538 .mode = 0644,
2539 .proc_handler = proc_dointvec_jiffies,
2540 },
2541 {
2542 .procname = "redirect_load",
2543 .data = &ip_rt_redirect_load,
2544 .maxlen = sizeof(int),
2545 .mode = 0644,
2546 .proc_handler = proc_dointvec,
2547 },
2548 {
2549 .procname = "redirect_number",
2550 .data = &ip_rt_redirect_number,
2551 .maxlen = sizeof(int),
2552 .mode = 0644,
2553 .proc_handler = proc_dointvec,
2554 },
2555 {
2556 .procname = "redirect_silence",
2557 .data = &ip_rt_redirect_silence,
2558 .maxlen = sizeof(int),
2559 .mode = 0644,
2560 .proc_handler = proc_dointvec,
2561 },
2562 {
2563 .procname = "error_cost",
2564 .data = &ip_rt_error_cost,
2565 .maxlen = sizeof(int),
2566 .mode = 0644,
2567 .proc_handler = proc_dointvec,
2568 },
2569 {
2570 .procname = "error_burst",
2571 .data = &ip_rt_error_burst,
2572 .maxlen = sizeof(int),
2573 .mode = 0644,
2574 .proc_handler = proc_dointvec,
2575 },
2576 {
2577 .procname = "gc_elasticity",
2578 .data = &ip_rt_gc_elasticity,
2579 .maxlen = sizeof(int),
2580 .mode = 0644,
2581 .proc_handler = proc_dointvec,
2582 },
2583 {
2584 .procname = "mtu_expires",
2585 .data = &ip_rt_mtu_expires,
2586 .maxlen = sizeof(int),
2587 .mode = 0644,
2588 .proc_handler = proc_dointvec_jiffies,
2589 },
2590 {
2591 .procname = "min_pmtu",
2592 .data = &ip_rt_min_pmtu,
2593 .maxlen = sizeof(int),
2594 .mode = 0644,
2595 .proc_handler = proc_dointvec,
2596 },
2597 {
2598 .procname = "min_adv_mss",
2599 .data = &ip_rt_min_advmss,
2600 .maxlen = sizeof(int),
2601 .mode = 0644,
2602 .proc_handler = proc_dointvec,
2603 },
2604 { }
2605};
2606
2607static struct ctl_table ipv4_route_flush_table[] = {
2608 {
2609 .procname = "flush",
2610 .maxlen = sizeof(int),
2611 .mode = 0200,
2612 .proc_handler = ipv4_sysctl_rtcache_flush,
2613 },
2614 { },
2615};
2616
2617static __net_init int sysctl_route_net_init(struct net *net)
2618{
2619 struct ctl_table *tbl;
2620
2621 tbl = ipv4_route_flush_table;
2622 if (!net_eq(net, &init_net)) {
2623 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2624 if (tbl == NULL)
2625 goto err_dup;
2626
2627 /* Don't export sysctls to unprivileged users */
2628 if (net->user_ns != &init_user_ns)
2629 tbl[0].procname = NULL;
2630 }
2631 tbl[0].extra1 = net;
2632
2633 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2634 if (net->ipv4.route_hdr == NULL)
2635 goto err_reg;
2636 return 0;
2637
2638err_reg:
2639 if (tbl != ipv4_route_flush_table)
2640 kfree(tbl);
2641err_dup:
2642 return -ENOMEM;
2643}
2644
2645static __net_exit void sysctl_route_net_exit(struct net *net)
2646{
2647 struct ctl_table *tbl;
2648
2649 tbl = net->ipv4.route_hdr->ctl_table_arg;
2650 unregister_net_sysctl_table(net->ipv4.route_hdr);
2651 BUG_ON(tbl == ipv4_route_flush_table);
2652 kfree(tbl);
2653}
2654
2655static __net_initdata struct pernet_operations sysctl_route_ops = {
2656 .init = sysctl_route_net_init,
2657 .exit = sysctl_route_net_exit,
2658};
2659#endif
2660
2661static __net_init int rt_genid_init(struct net *net)
2662{
2663 atomic_set(&net->ipv4.rt_genid, 0);
2664 atomic_set(&net->fnhe_genid, 0);
2665 get_random_bytes(&net->ipv4.dev_addr_genid,
2666 sizeof(net->ipv4.dev_addr_genid));
2667 return 0;
2668}
2669
2670static __net_initdata struct pernet_operations rt_genid_ops = {
2671 .init = rt_genid_init,
2672};
2673
2674static int __net_init ipv4_inetpeer_init(struct net *net)
2675{
2676 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2677
2678 if (!bp)
2679 return -ENOMEM;
2680 inet_peer_base_init(bp);
2681 net->ipv4.peers = bp;
2682 return 0;
2683}
2684
2685static void __net_exit ipv4_inetpeer_exit(struct net *net)
2686{
2687 struct inet_peer_base *bp = net->ipv4.peers;
2688
2689 net->ipv4.peers = NULL;
2690 inetpeer_invalidate_tree(bp);
2691 kfree(bp);
2692}
2693
2694static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2695 .init = ipv4_inetpeer_init,
2696 .exit = ipv4_inetpeer_exit,
2697};
2698
2699#ifdef CONFIG_IP_ROUTE_CLASSID
2700struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2701#endif /* CONFIG_IP_ROUTE_CLASSID */
2702
2703int __init ip_rt_init(void)
2704{
2705 int rc = 0;
2706
2707#ifdef CONFIG_IP_ROUTE_CLASSID
2708 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2709 if (!ip_rt_acct)
2710 panic("IP: failed to allocate ip_rt_acct\n");
2711#endif
2712
2713 ipv4_dst_ops.kmem_cachep =
2714 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2715 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2716
2717 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2718
2719 if (dst_entries_init(&ipv4_dst_ops) < 0)
2720 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2721
2722 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2723 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2724
2725 ipv4_dst_ops.gc_thresh = ~0;
2726 ip_rt_max_size = INT_MAX;
2727
2728 devinet_init();
2729 ip_fib_init();
2730
2731 if (ip_rt_proc_init())
2732 pr_err("Unable to create route proc files\n");
2733#ifdef CONFIG_XFRM
2734 xfrm_init();
2735 xfrm4_init();
2736#endif
2737 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2738
2739#ifdef CONFIG_SYSCTL
2740 register_pernet_subsys(&sysctl_route_ops);
2741#endif
2742 register_pernet_subsys(&rt_genid_ops);
2743 register_pernet_subsys(&ipv4_inetpeer_ops);
2744 return rc;
2745}
2746
2747#ifdef CONFIG_SYSCTL
2748/*
2749 * We really need to sanitize the damn ipv4 init order, then all
2750 * this nonsense will go away.
2751 */
2752void __init ip_static_sysctl_init(void)
2753{
2754 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2755}
2756#endif