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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 <linux/jhash.h>
93#include <net/dst.h>
94#include <net/dst_metadata.h>
95#include <net/net_namespace.h>
96#include <net/protocol.h>
97#include <net/ip.h>
98#include <net/route.h>
99#include <net/inetpeer.h>
100#include <net/sock.h>
101#include <net/ip_fib.h>
102#include <net/arp.h>
103#include <net/tcp.h>
104#include <net/icmp.h>
105#include <net/xfrm.h>
106#include <net/lwtunnel.h>
107#include <net/netevent.h>
108#include <net/rtnetlink.h>
109#ifdef CONFIG_SYSCTL
110#include <linux/sysctl.h>
111#include <linux/kmemleak.h>
112#endif
113#include <net/secure_seq.h>
114#include <net/ip_tunnels.h>
115#include <net/l3mdev.h>
116
117#define RT_FL_TOS(oldflp4) \
118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
119
120#define RT_GC_TIMEOUT (300*HZ)
121
122static int ip_rt_max_size;
123static int ip_rt_redirect_number __read_mostly = 9;
124static int ip_rt_redirect_load __read_mostly = HZ / 50;
125static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
126static int ip_rt_error_cost __read_mostly = HZ;
127static int ip_rt_error_burst __read_mostly = 5 * HZ;
128static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
129static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
130static int ip_rt_min_advmss __read_mostly = 256;
131
132static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
133/*
134 * Interface to generic destination cache.
135 */
136
137static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
138static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
139static unsigned int ipv4_mtu(const struct dst_entry *dst);
140static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
141static void ipv4_link_failure(struct sk_buff *skb);
142static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
143 struct sk_buff *skb, u32 mtu);
144static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146static void ipv4_dst_destroy(struct dst_entry *dst);
147
148static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
149{
150 WARN_ON(1);
151 return NULL;
152}
153
154static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
155 struct sk_buff *skb,
156 const void *daddr);
157
158static struct dst_ops ipv4_dst_ops = {
159 .family = AF_INET,
160 .check = ipv4_dst_check,
161 .default_advmss = ipv4_default_advmss,
162 .mtu = ipv4_mtu,
163 .cow_metrics = ipv4_cow_metrics,
164 .destroy = ipv4_dst_destroy,
165 .negative_advice = ipv4_negative_advice,
166 .link_failure = ipv4_link_failure,
167 .update_pmtu = ip_rt_update_pmtu,
168 .redirect = ip_do_redirect,
169 .local_out = __ip_local_out,
170 .neigh_lookup = ipv4_neigh_lookup,
171};
172
173#define ECN_OR_COST(class) TC_PRIO_##class
174
175const __u8 ip_tos2prio[16] = {
176 TC_PRIO_BESTEFFORT,
177 ECN_OR_COST(BESTEFFORT),
178 TC_PRIO_BESTEFFORT,
179 ECN_OR_COST(BESTEFFORT),
180 TC_PRIO_BULK,
181 ECN_OR_COST(BULK),
182 TC_PRIO_BULK,
183 ECN_OR_COST(BULK),
184 TC_PRIO_INTERACTIVE,
185 ECN_OR_COST(INTERACTIVE),
186 TC_PRIO_INTERACTIVE,
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE_BULK,
189 ECN_OR_COST(INTERACTIVE_BULK),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK)
192};
193EXPORT_SYMBOL(ip_tos2prio);
194
195static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
196#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
197
198#ifdef CONFIG_PROC_FS
199static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
200{
201 if (*pos)
202 return NULL;
203 return SEQ_START_TOKEN;
204}
205
206static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
207{
208 ++*pos;
209 return NULL;
210}
211
212static void rt_cache_seq_stop(struct seq_file *seq, void *v)
213{
214}
215
216static int rt_cache_seq_show(struct seq_file *seq, void *v)
217{
218 if (v == SEQ_START_TOKEN)
219 seq_printf(seq, "%-127s\n",
220 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
221 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
222 "HHUptod\tSpecDst");
223 return 0;
224}
225
226static const struct seq_operations rt_cache_seq_ops = {
227 .start = rt_cache_seq_start,
228 .next = rt_cache_seq_next,
229 .stop = rt_cache_seq_stop,
230 .show = rt_cache_seq_show,
231};
232
233static int rt_cache_seq_open(struct inode *inode, struct file *file)
234{
235 return seq_open(file, &rt_cache_seq_ops);
236}
237
238static const struct file_operations rt_cache_seq_fops = {
239 .owner = THIS_MODULE,
240 .open = rt_cache_seq_open,
241 .read = seq_read,
242 .llseek = seq_lseek,
243 .release = seq_release,
244};
245
246
247static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
248{
249 int cpu;
250
251 if (*pos == 0)
252 return SEQ_START_TOKEN;
253
254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
255 if (!cpu_possible(cpu))
256 continue;
257 *pos = cpu+1;
258 return &per_cpu(rt_cache_stat, cpu);
259 }
260 return NULL;
261}
262
263static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
264{
265 int cpu;
266
267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
268 if (!cpu_possible(cpu))
269 continue;
270 *pos = cpu+1;
271 return &per_cpu(rt_cache_stat, cpu);
272 }
273 return NULL;
274
275}
276
277static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
278{
279
280}
281
282static int rt_cpu_seq_show(struct seq_file *seq, void *v)
283{
284 struct rt_cache_stat *st = v;
285
286 if (v == SEQ_START_TOKEN) {
287 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
288 return 0;
289 }
290
291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
293 dst_entries_get_slow(&ipv4_dst_ops),
294 0, /* st->in_hit */
295 st->in_slow_tot,
296 st->in_slow_mc,
297 st->in_no_route,
298 st->in_brd,
299 st->in_martian_dst,
300 st->in_martian_src,
301
302 0, /* st->out_hit */
303 st->out_slow_tot,
304 st->out_slow_mc,
305
306 0, /* st->gc_total */
307 0, /* st->gc_ignored */
308 0, /* st->gc_goal_miss */
309 0, /* st->gc_dst_overflow */
310 0, /* st->in_hlist_search */
311 0 /* st->out_hlist_search */
312 );
313 return 0;
314}
315
316static const struct seq_operations rt_cpu_seq_ops = {
317 .start = rt_cpu_seq_start,
318 .next = rt_cpu_seq_next,
319 .stop = rt_cpu_seq_stop,
320 .show = rt_cpu_seq_show,
321};
322
323
324static int rt_cpu_seq_open(struct inode *inode, struct file *file)
325{
326 return seq_open(file, &rt_cpu_seq_ops);
327}
328
329static const struct file_operations rt_cpu_seq_fops = {
330 .owner = THIS_MODULE,
331 .open = rt_cpu_seq_open,
332 .read = seq_read,
333 .llseek = seq_lseek,
334 .release = seq_release,
335};
336
337#ifdef CONFIG_IP_ROUTE_CLASSID
338static int rt_acct_proc_show(struct seq_file *m, void *v)
339{
340 struct ip_rt_acct *dst, *src;
341 unsigned int i, j;
342
343 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
344 if (!dst)
345 return -ENOMEM;
346
347 for_each_possible_cpu(i) {
348 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
349 for (j = 0; j < 256; j++) {
350 dst[j].o_bytes += src[j].o_bytes;
351 dst[j].o_packets += src[j].o_packets;
352 dst[j].i_bytes += src[j].i_bytes;
353 dst[j].i_packets += src[j].i_packets;
354 }
355 }
356
357 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
358 kfree(dst);
359 return 0;
360}
361
362static int rt_acct_proc_open(struct inode *inode, struct file *file)
363{
364 return single_open(file, rt_acct_proc_show, NULL);
365}
366
367static const struct file_operations rt_acct_proc_fops = {
368 .owner = THIS_MODULE,
369 .open = rt_acct_proc_open,
370 .read = seq_read,
371 .llseek = seq_lseek,
372 .release = single_release,
373};
374#endif
375
376static int __net_init ip_rt_do_proc_init(struct net *net)
377{
378 struct proc_dir_entry *pde;
379
380 pde = proc_create("rt_cache", S_IRUGO, net->proc_net,
381 &rt_cache_seq_fops);
382 if (!pde)
383 goto err1;
384
385 pde = proc_create("rt_cache", S_IRUGO,
386 net->proc_net_stat, &rt_cpu_seq_fops);
387 if (!pde)
388 goto err2;
389
390#ifdef CONFIG_IP_ROUTE_CLASSID
391 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
392 if (!pde)
393 goto err3;
394#endif
395 return 0;
396
397#ifdef CONFIG_IP_ROUTE_CLASSID
398err3:
399 remove_proc_entry("rt_cache", net->proc_net_stat);
400#endif
401err2:
402 remove_proc_entry("rt_cache", net->proc_net);
403err1:
404 return -ENOMEM;
405}
406
407static void __net_exit ip_rt_do_proc_exit(struct net *net)
408{
409 remove_proc_entry("rt_cache", net->proc_net_stat);
410 remove_proc_entry("rt_cache", net->proc_net);
411#ifdef CONFIG_IP_ROUTE_CLASSID
412 remove_proc_entry("rt_acct", net->proc_net);
413#endif
414}
415
416static struct pernet_operations ip_rt_proc_ops __net_initdata = {
417 .init = ip_rt_do_proc_init,
418 .exit = ip_rt_do_proc_exit,
419};
420
421static int __init ip_rt_proc_init(void)
422{
423 return register_pernet_subsys(&ip_rt_proc_ops);
424}
425
426#else
427static inline int ip_rt_proc_init(void)
428{
429 return 0;
430}
431#endif /* CONFIG_PROC_FS */
432
433static inline bool rt_is_expired(const struct rtable *rth)
434{
435 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
436}
437
438void rt_cache_flush(struct net *net)
439{
440 rt_genid_bump_ipv4(net);
441}
442
443static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
444 struct sk_buff *skb,
445 const void *daddr)
446{
447 struct net_device *dev = dst->dev;
448 const __be32 *pkey = daddr;
449 const struct rtable *rt;
450 struct neighbour *n;
451
452 rt = (const struct rtable *) dst;
453 if (rt->rt_gateway)
454 pkey = (const __be32 *) &rt->rt_gateway;
455 else if (skb)
456 pkey = &ip_hdr(skb)->daddr;
457
458 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
459 if (n)
460 return n;
461 return neigh_create(&arp_tbl, pkey, dev);
462}
463
464#define IP_IDENTS_SZ 2048u
465
466static atomic_t *ip_idents __read_mostly;
467static u32 *ip_tstamps __read_mostly;
468
469/* In order to protect privacy, we add a perturbation to identifiers
470 * if one generator is seldom used. This makes hard for an attacker
471 * to infer how many packets were sent between two points in time.
472 */
473u32 ip_idents_reserve(u32 hash, int segs)
474{
475 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
476 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
477 u32 old = ACCESS_ONCE(*p_tstamp);
478 u32 now = (u32)jiffies;
479 u32 delta = 0;
480
481 if (old != now && cmpxchg(p_tstamp, old, now) == old)
482 delta = prandom_u32_max(now - old);
483
484 return atomic_add_return(segs + delta, p_id) - segs;
485}
486EXPORT_SYMBOL(ip_idents_reserve);
487
488void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
489{
490 static u32 ip_idents_hashrnd __read_mostly;
491 u32 hash, id;
492
493 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
494
495 hash = jhash_3words((__force u32)iph->daddr,
496 (__force u32)iph->saddr,
497 iph->protocol ^ net_hash_mix(net),
498 ip_idents_hashrnd);
499 id = ip_idents_reserve(hash, segs);
500 iph->id = htons(id);
501}
502EXPORT_SYMBOL(__ip_select_ident);
503
504static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk,
505 const struct iphdr *iph,
506 int oif, u8 tos,
507 u8 prot, u32 mark, int flow_flags)
508{
509 if (sk) {
510 const struct inet_sock *inet = inet_sk(sk);
511
512 oif = sk->sk_bound_dev_if;
513 mark = sk->sk_mark;
514 tos = RT_CONN_FLAGS(sk);
515 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
516 }
517 flowi4_init_output(fl4, oif, mark, tos,
518 RT_SCOPE_UNIVERSE, prot,
519 flow_flags,
520 iph->daddr, iph->saddr, 0, 0);
521}
522
523static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
524 const struct sock *sk)
525{
526 const struct iphdr *iph = ip_hdr(skb);
527 int oif = skb->dev->ifindex;
528 u8 tos = RT_TOS(iph->tos);
529 u8 prot = iph->protocol;
530 u32 mark = skb->mark;
531
532 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0);
533}
534
535static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
536{
537 const struct inet_sock *inet = inet_sk(sk);
538 const struct ip_options_rcu *inet_opt;
539 __be32 daddr = inet->inet_daddr;
540
541 rcu_read_lock();
542 inet_opt = rcu_dereference(inet->inet_opt);
543 if (inet_opt && inet_opt->opt.srr)
544 daddr = inet_opt->opt.faddr;
545 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
546 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
547 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
548 inet_sk_flowi_flags(sk),
549 daddr, inet->inet_saddr, 0, 0);
550 rcu_read_unlock();
551}
552
553static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
554 const struct sk_buff *skb)
555{
556 if (skb)
557 build_skb_flow_key(fl4, skb, sk);
558 else
559 build_sk_flow_key(fl4, sk);
560}
561
562static inline void rt_free(struct rtable *rt)
563{
564 call_rcu(&rt->dst.rcu_head, dst_rcu_free);
565}
566
567static DEFINE_SPINLOCK(fnhe_lock);
568
569static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
570{
571 struct rtable *rt;
572
573 rt = rcu_dereference(fnhe->fnhe_rth_input);
574 if (rt) {
575 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
576 rt_free(rt);
577 }
578 rt = rcu_dereference(fnhe->fnhe_rth_output);
579 if (rt) {
580 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
581 rt_free(rt);
582 }
583}
584
585static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
586{
587 struct fib_nh_exception *fnhe, *oldest;
588
589 oldest = rcu_dereference(hash->chain);
590 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
591 fnhe = rcu_dereference(fnhe->fnhe_next)) {
592 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
593 oldest = fnhe;
594 }
595 fnhe_flush_routes(oldest);
596 return oldest;
597}
598
599static inline u32 fnhe_hashfun(__be32 daddr)
600{
601 static u32 fnhe_hashrnd __read_mostly;
602 u32 hval;
603
604 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
605 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
606 return hash_32(hval, FNHE_HASH_SHIFT);
607}
608
609static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
610{
611 rt->rt_pmtu = fnhe->fnhe_pmtu;
612 rt->dst.expires = fnhe->fnhe_expires;
613
614 if (fnhe->fnhe_gw) {
615 rt->rt_flags |= RTCF_REDIRECTED;
616 rt->rt_gateway = fnhe->fnhe_gw;
617 rt->rt_uses_gateway = 1;
618 }
619}
620
621static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
622 u32 pmtu, unsigned long expires)
623{
624 struct fnhe_hash_bucket *hash;
625 struct fib_nh_exception *fnhe;
626 struct rtable *rt;
627 unsigned int i;
628 int depth;
629 u32 hval = fnhe_hashfun(daddr);
630
631 spin_lock_bh(&fnhe_lock);
632
633 hash = rcu_dereference(nh->nh_exceptions);
634 if (!hash) {
635 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
636 if (!hash)
637 goto out_unlock;
638 rcu_assign_pointer(nh->nh_exceptions, hash);
639 }
640
641 hash += hval;
642
643 depth = 0;
644 for (fnhe = rcu_dereference(hash->chain); fnhe;
645 fnhe = rcu_dereference(fnhe->fnhe_next)) {
646 if (fnhe->fnhe_daddr == daddr)
647 break;
648 depth++;
649 }
650
651 if (fnhe) {
652 if (gw)
653 fnhe->fnhe_gw = gw;
654 if (pmtu) {
655 fnhe->fnhe_pmtu = pmtu;
656 fnhe->fnhe_expires = max(1UL, expires);
657 }
658 /* Update all cached dsts too */
659 rt = rcu_dereference(fnhe->fnhe_rth_input);
660 if (rt)
661 fill_route_from_fnhe(rt, fnhe);
662 rt = rcu_dereference(fnhe->fnhe_rth_output);
663 if (rt)
664 fill_route_from_fnhe(rt, fnhe);
665 } else {
666 if (depth > FNHE_RECLAIM_DEPTH)
667 fnhe = fnhe_oldest(hash);
668 else {
669 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
670 if (!fnhe)
671 goto out_unlock;
672
673 fnhe->fnhe_next = hash->chain;
674 rcu_assign_pointer(hash->chain, fnhe);
675 }
676 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
677 fnhe->fnhe_daddr = daddr;
678 fnhe->fnhe_gw = gw;
679 fnhe->fnhe_pmtu = pmtu;
680 fnhe->fnhe_expires = expires;
681
682 /* Exception created; mark the cached routes for the nexthop
683 * stale, so anyone caching it rechecks if this exception
684 * applies to them.
685 */
686 rt = rcu_dereference(nh->nh_rth_input);
687 if (rt)
688 rt->dst.obsolete = DST_OBSOLETE_KILL;
689
690 for_each_possible_cpu(i) {
691 struct rtable __rcu **prt;
692 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
693 rt = rcu_dereference(*prt);
694 if (rt)
695 rt->dst.obsolete = DST_OBSOLETE_KILL;
696 }
697 }
698
699 fnhe->fnhe_stamp = jiffies;
700
701out_unlock:
702 spin_unlock_bh(&fnhe_lock);
703}
704
705static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
706 bool kill_route)
707{
708 __be32 new_gw = icmp_hdr(skb)->un.gateway;
709 __be32 old_gw = ip_hdr(skb)->saddr;
710 struct net_device *dev = skb->dev;
711 struct in_device *in_dev;
712 struct fib_result res;
713 struct neighbour *n;
714 struct net *net;
715
716 switch (icmp_hdr(skb)->code & 7) {
717 case ICMP_REDIR_NET:
718 case ICMP_REDIR_NETTOS:
719 case ICMP_REDIR_HOST:
720 case ICMP_REDIR_HOSTTOS:
721 break;
722
723 default:
724 return;
725 }
726
727 if (rt->rt_gateway != old_gw)
728 return;
729
730 in_dev = __in_dev_get_rcu(dev);
731 if (!in_dev)
732 return;
733
734 net = dev_net(dev);
735 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
736 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
737 ipv4_is_zeronet(new_gw))
738 goto reject_redirect;
739
740 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
741 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
742 goto reject_redirect;
743 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
744 goto reject_redirect;
745 } else {
746 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
747 goto reject_redirect;
748 }
749
750 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
751 if (!IS_ERR(n)) {
752 if (!(n->nud_state & NUD_VALID)) {
753 neigh_event_send(n, NULL);
754 } else {
755 if (fib_lookup(net, fl4, &res, 0) == 0) {
756 struct fib_nh *nh = &FIB_RES_NH(res);
757
758 update_or_create_fnhe(nh, fl4->daddr, new_gw,
759 0, jiffies + ip_rt_gc_timeout);
760 }
761 if (kill_route)
762 rt->dst.obsolete = DST_OBSOLETE_KILL;
763 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
764 }
765 neigh_release(n);
766 }
767 return;
768
769reject_redirect:
770#ifdef CONFIG_IP_ROUTE_VERBOSE
771 if (IN_DEV_LOG_MARTIANS(in_dev)) {
772 const struct iphdr *iph = (const struct iphdr *) skb->data;
773 __be32 daddr = iph->daddr;
774 __be32 saddr = iph->saddr;
775
776 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
777 " Advised path = %pI4 -> %pI4\n",
778 &old_gw, dev->name, &new_gw,
779 &saddr, &daddr);
780 }
781#endif
782 ;
783}
784
785static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
786{
787 struct rtable *rt;
788 struct flowi4 fl4;
789 const struct iphdr *iph = (const struct iphdr *) skb->data;
790 int oif = skb->dev->ifindex;
791 u8 tos = RT_TOS(iph->tos);
792 u8 prot = iph->protocol;
793 u32 mark = skb->mark;
794
795 rt = (struct rtable *) dst;
796
797 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
798 __ip_do_redirect(rt, skb, &fl4, true);
799}
800
801static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
802{
803 struct rtable *rt = (struct rtable *)dst;
804 struct dst_entry *ret = dst;
805
806 if (rt) {
807 if (dst->obsolete > 0) {
808 ip_rt_put(rt);
809 ret = NULL;
810 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
811 rt->dst.expires) {
812 ip_rt_put(rt);
813 ret = NULL;
814 }
815 }
816 return ret;
817}
818
819/*
820 * Algorithm:
821 * 1. The first ip_rt_redirect_number redirects are sent
822 * with exponential backoff, then we stop sending them at all,
823 * assuming that the host ignores our redirects.
824 * 2. If we did not see packets requiring redirects
825 * during ip_rt_redirect_silence, we assume that the host
826 * forgot redirected route and start to send redirects again.
827 *
828 * This algorithm is much cheaper and more intelligent than dumb load limiting
829 * in icmp.c.
830 *
831 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
832 * and "frag. need" (breaks PMTU discovery) in icmp.c.
833 */
834
835void ip_rt_send_redirect(struct sk_buff *skb)
836{
837 struct rtable *rt = skb_rtable(skb);
838 struct in_device *in_dev;
839 struct inet_peer *peer;
840 struct net *net;
841 int log_martians;
842 int vif;
843
844 rcu_read_lock();
845 in_dev = __in_dev_get_rcu(rt->dst.dev);
846 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
847 rcu_read_unlock();
848 return;
849 }
850 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
851 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
852 rcu_read_unlock();
853
854 net = dev_net(rt->dst.dev);
855 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
856 if (!peer) {
857 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
858 rt_nexthop(rt, ip_hdr(skb)->daddr));
859 return;
860 }
861
862 /* No redirected packets during ip_rt_redirect_silence;
863 * reset the algorithm.
864 */
865 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
866 peer->rate_tokens = 0;
867
868 /* Too many ignored redirects; do not send anything
869 * set dst.rate_last to the last seen redirected packet.
870 */
871 if (peer->rate_tokens >= ip_rt_redirect_number) {
872 peer->rate_last = jiffies;
873 goto out_put_peer;
874 }
875
876 /* Check for load limit; set rate_last to the latest sent
877 * redirect.
878 */
879 if (peer->rate_tokens == 0 ||
880 time_after(jiffies,
881 (peer->rate_last +
882 (ip_rt_redirect_load << peer->rate_tokens)))) {
883 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
884
885 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
886 peer->rate_last = jiffies;
887 ++peer->rate_tokens;
888#ifdef CONFIG_IP_ROUTE_VERBOSE
889 if (log_martians &&
890 peer->rate_tokens == ip_rt_redirect_number)
891 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
892 &ip_hdr(skb)->saddr, inet_iif(skb),
893 &ip_hdr(skb)->daddr, &gw);
894#endif
895 }
896out_put_peer:
897 inet_putpeer(peer);
898}
899
900static int ip_error(struct sk_buff *skb)
901{
902 struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
903 struct rtable *rt = skb_rtable(skb);
904 struct inet_peer *peer;
905 unsigned long now;
906 struct net *net;
907 bool send;
908 int code;
909
910 /* IP on this device is disabled. */
911 if (!in_dev)
912 goto out;
913
914 net = dev_net(rt->dst.dev);
915 if (!IN_DEV_FORWARD(in_dev)) {
916 switch (rt->dst.error) {
917 case EHOSTUNREACH:
918 IP_INC_STATS_BH(net, IPSTATS_MIB_INADDRERRORS);
919 break;
920
921 case ENETUNREACH:
922 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
923 break;
924 }
925 goto out;
926 }
927
928 switch (rt->dst.error) {
929 case EINVAL:
930 default:
931 goto out;
932 case EHOSTUNREACH:
933 code = ICMP_HOST_UNREACH;
934 break;
935 case ENETUNREACH:
936 code = ICMP_NET_UNREACH;
937 IP_INC_STATS_BH(net, IPSTATS_MIB_INNOROUTES);
938 break;
939 case EACCES:
940 code = ICMP_PKT_FILTERED;
941 break;
942 }
943
944 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
945 l3mdev_master_ifindex(skb->dev), 1);
946
947 send = true;
948 if (peer) {
949 now = jiffies;
950 peer->rate_tokens += now - peer->rate_last;
951 if (peer->rate_tokens > ip_rt_error_burst)
952 peer->rate_tokens = ip_rt_error_burst;
953 peer->rate_last = now;
954 if (peer->rate_tokens >= ip_rt_error_cost)
955 peer->rate_tokens -= ip_rt_error_cost;
956 else
957 send = false;
958 inet_putpeer(peer);
959 }
960 if (send)
961 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
962
963out: kfree_skb(skb);
964 return 0;
965}
966
967static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
968{
969 struct dst_entry *dst = &rt->dst;
970 struct fib_result res;
971
972 if (dst_metric_locked(dst, RTAX_MTU))
973 return;
974
975 if (ipv4_mtu(dst) < mtu)
976 return;
977
978 if (mtu < ip_rt_min_pmtu)
979 mtu = ip_rt_min_pmtu;
980
981 if (rt->rt_pmtu == mtu &&
982 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
983 return;
984
985 rcu_read_lock();
986 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
987 struct fib_nh *nh = &FIB_RES_NH(res);
988
989 update_or_create_fnhe(nh, fl4->daddr, 0, mtu,
990 jiffies + ip_rt_mtu_expires);
991 }
992 rcu_read_unlock();
993}
994
995static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
996 struct sk_buff *skb, u32 mtu)
997{
998 struct rtable *rt = (struct rtable *) dst;
999 struct flowi4 fl4;
1000
1001 ip_rt_build_flow_key(&fl4, sk, skb);
1002 __ip_rt_update_pmtu(rt, &fl4, mtu);
1003}
1004
1005void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1006 int oif, u32 mark, u8 protocol, int flow_flags)
1007{
1008 const struct iphdr *iph = (const struct iphdr *) skb->data;
1009 struct flowi4 fl4;
1010 struct rtable *rt;
1011
1012 if (!mark)
1013 mark = IP4_REPLY_MARK(net, skb->mark);
1014
1015 __build_flow_key(&fl4, NULL, iph, oif,
1016 RT_TOS(iph->tos), protocol, mark, flow_flags);
1017 rt = __ip_route_output_key(net, &fl4);
1018 if (!IS_ERR(rt)) {
1019 __ip_rt_update_pmtu(rt, &fl4, mtu);
1020 ip_rt_put(rt);
1021 }
1022}
1023EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1024
1025static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1026{
1027 const struct iphdr *iph = (const struct iphdr *) skb->data;
1028 struct flowi4 fl4;
1029 struct rtable *rt;
1030
1031 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1032
1033 if (!fl4.flowi4_mark)
1034 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1035
1036 rt = __ip_route_output_key(sock_net(sk), &fl4);
1037 if (!IS_ERR(rt)) {
1038 __ip_rt_update_pmtu(rt, &fl4, mtu);
1039 ip_rt_put(rt);
1040 }
1041}
1042
1043void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1044{
1045 const struct iphdr *iph = (const struct iphdr *) skb->data;
1046 struct flowi4 fl4;
1047 struct rtable *rt;
1048 struct dst_entry *odst = NULL;
1049 bool new = false;
1050
1051 bh_lock_sock(sk);
1052
1053 if (!ip_sk_accept_pmtu(sk))
1054 goto out;
1055
1056 odst = sk_dst_get(sk);
1057
1058 if (sock_owned_by_user(sk) || !odst) {
1059 __ipv4_sk_update_pmtu(skb, sk, mtu);
1060 goto out;
1061 }
1062
1063 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1064
1065 rt = (struct rtable *)odst;
1066 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1067 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1068 if (IS_ERR(rt))
1069 goto out;
1070
1071 new = true;
1072 }
1073
1074 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
1075
1076 if (!dst_check(&rt->dst, 0)) {
1077 if (new)
1078 dst_release(&rt->dst);
1079
1080 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1081 if (IS_ERR(rt))
1082 goto out;
1083
1084 new = true;
1085 }
1086
1087 if (new)
1088 sk_dst_set(sk, &rt->dst);
1089
1090out:
1091 bh_unlock_sock(sk);
1092 dst_release(odst);
1093}
1094EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1095
1096void ipv4_redirect(struct sk_buff *skb, struct net *net,
1097 int oif, u32 mark, u8 protocol, int flow_flags)
1098{
1099 const struct iphdr *iph = (const struct iphdr *) skb->data;
1100 struct flowi4 fl4;
1101 struct rtable *rt;
1102
1103 __build_flow_key(&fl4, NULL, iph, oif,
1104 RT_TOS(iph->tos), protocol, mark, flow_flags);
1105 rt = __ip_route_output_key(net, &fl4);
1106 if (!IS_ERR(rt)) {
1107 __ip_do_redirect(rt, skb, &fl4, false);
1108 ip_rt_put(rt);
1109 }
1110}
1111EXPORT_SYMBOL_GPL(ipv4_redirect);
1112
1113void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1114{
1115 const struct iphdr *iph = (const struct iphdr *) skb->data;
1116 struct flowi4 fl4;
1117 struct rtable *rt;
1118
1119 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
1120 rt = __ip_route_output_key(sock_net(sk), &fl4);
1121 if (!IS_ERR(rt)) {
1122 __ip_do_redirect(rt, skb, &fl4, false);
1123 ip_rt_put(rt);
1124 }
1125}
1126EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1127
1128static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1129{
1130 struct rtable *rt = (struct rtable *) dst;
1131
1132 /* All IPV4 dsts are created with ->obsolete set to the value
1133 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1134 * into this function always.
1135 *
1136 * When a PMTU/redirect information update invalidates a route,
1137 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1138 * DST_OBSOLETE_DEAD by dst_free().
1139 */
1140 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1141 return NULL;
1142 return dst;
1143}
1144
1145static void ipv4_link_failure(struct sk_buff *skb)
1146{
1147 struct rtable *rt;
1148
1149 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1150
1151 rt = skb_rtable(skb);
1152 if (rt)
1153 dst_set_expires(&rt->dst, 0);
1154}
1155
1156static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1157{
1158 pr_debug("%s: %pI4 -> %pI4, %s\n",
1159 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1160 skb->dev ? skb->dev->name : "?");
1161 kfree_skb(skb);
1162 WARN_ON(1);
1163 return 0;
1164}
1165
1166/*
1167 We do not cache source address of outgoing interface,
1168 because it is used only by IP RR, TS and SRR options,
1169 so that it out of fast path.
1170
1171 BTW remember: "addr" is allowed to be not aligned
1172 in IP options!
1173 */
1174
1175void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1176{
1177 __be32 src;
1178
1179 if (rt_is_output_route(rt))
1180 src = ip_hdr(skb)->saddr;
1181 else {
1182 struct fib_result res;
1183 struct flowi4 fl4;
1184 struct iphdr *iph;
1185
1186 iph = ip_hdr(skb);
1187
1188 memset(&fl4, 0, sizeof(fl4));
1189 fl4.daddr = iph->daddr;
1190 fl4.saddr = iph->saddr;
1191 fl4.flowi4_tos = RT_TOS(iph->tos);
1192 fl4.flowi4_oif = rt->dst.dev->ifindex;
1193 fl4.flowi4_iif = skb->dev->ifindex;
1194 fl4.flowi4_mark = skb->mark;
1195
1196 rcu_read_lock();
1197 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1198 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1199 else
1200 src = inet_select_addr(rt->dst.dev,
1201 rt_nexthop(rt, iph->daddr),
1202 RT_SCOPE_UNIVERSE);
1203 rcu_read_unlock();
1204 }
1205 memcpy(addr, &src, 4);
1206}
1207
1208#ifdef CONFIG_IP_ROUTE_CLASSID
1209static void set_class_tag(struct rtable *rt, u32 tag)
1210{
1211 if (!(rt->dst.tclassid & 0xFFFF))
1212 rt->dst.tclassid |= tag & 0xFFFF;
1213 if (!(rt->dst.tclassid & 0xFFFF0000))
1214 rt->dst.tclassid |= tag & 0xFFFF0000;
1215}
1216#endif
1217
1218static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1219{
1220 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS);
1221
1222 if (advmss == 0) {
1223 advmss = max_t(unsigned int, dst->dev->mtu - 40,
1224 ip_rt_min_advmss);
1225 if (advmss > 65535 - 40)
1226 advmss = 65535 - 40;
1227 }
1228 return advmss;
1229}
1230
1231static unsigned int ipv4_mtu(const struct dst_entry *dst)
1232{
1233 const struct rtable *rt = (const struct rtable *) dst;
1234 unsigned int mtu = rt->rt_pmtu;
1235
1236 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1237 mtu = dst_metric_raw(dst, RTAX_MTU);
1238
1239 if (mtu)
1240 return mtu;
1241
1242 mtu = dst->dev->mtu;
1243
1244 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) {
1245 if (rt->rt_uses_gateway && mtu > 576)
1246 mtu = 576;
1247 }
1248
1249 return min_t(unsigned int, mtu, IP_MAX_MTU);
1250}
1251
1252static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1253{
1254 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1255 struct fib_nh_exception *fnhe;
1256 u32 hval;
1257
1258 if (!hash)
1259 return NULL;
1260
1261 hval = fnhe_hashfun(daddr);
1262
1263 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1264 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1265 if (fnhe->fnhe_daddr == daddr)
1266 return fnhe;
1267 }
1268 return NULL;
1269}
1270
1271static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1272 __be32 daddr)
1273{
1274 bool ret = false;
1275
1276 spin_lock_bh(&fnhe_lock);
1277
1278 if (daddr == fnhe->fnhe_daddr) {
1279 struct rtable __rcu **porig;
1280 struct rtable *orig;
1281 int genid = fnhe_genid(dev_net(rt->dst.dev));
1282
1283 if (rt_is_input_route(rt))
1284 porig = &fnhe->fnhe_rth_input;
1285 else
1286 porig = &fnhe->fnhe_rth_output;
1287 orig = rcu_dereference(*porig);
1288
1289 if (fnhe->fnhe_genid != genid) {
1290 fnhe->fnhe_genid = genid;
1291 fnhe->fnhe_gw = 0;
1292 fnhe->fnhe_pmtu = 0;
1293 fnhe->fnhe_expires = 0;
1294 fnhe_flush_routes(fnhe);
1295 orig = NULL;
1296 }
1297 fill_route_from_fnhe(rt, fnhe);
1298 if (!rt->rt_gateway)
1299 rt->rt_gateway = daddr;
1300
1301 if (!(rt->dst.flags & DST_NOCACHE)) {
1302 rcu_assign_pointer(*porig, rt);
1303 if (orig)
1304 rt_free(orig);
1305 ret = true;
1306 }
1307
1308 fnhe->fnhe_stamp = jiffies;
1309 }
1310 spin_unlock_bh(&fnhe_lock);
1311
1312 return ret;
1313}
1314
1315static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1316{
1317 struct rtable *orig, *prev, **p;
1318 bool ret = true;
1319
1320 if (rt_is_input_route(rt)) {
1321 p = (struct rtable **)&nh->nh_rth_input;
1322 } else {
1323 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1324 }
1325 orig = *p;
1326
1327 prev = cmpxchg(p, orig, rt);
1328 if (prev == orig) {
1329 if (orig)
1330 rt_free(orig);
1331 } else
1332 ret = false;
1333
1334 return ret;
1335}
1336
1337struct uncached_list {
1338 spinlock_t lock;
1339 struct list_head head;
1340};
1341
1342static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1343
1344static void rt_add_uncached_list(struct rtable *rt)
1345{
1346 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1347
1348 rt->rt_uncached_list = ul;
1349
1350 spin_lock_bh(&ul->lock);
1351 list_add_tail(&rt->rt_uncached, &ul->head);
1352 spin_unlock_bh(&ul->lock);
1353}
1354
1355static void ipv4_dst_destroy(struct dst_entry *dst)
1356{
1357 struct rtable *rt = (struct rtable *) dst;
1358
1359 if (!list_empty(&rt->rt_uncached)) {
1360 struct uncached_list *ul = rt->rt_uncached_list;
1361
1362 spin_lock_bh(&ul->lock);
1363 list_del(&rt->rt_uncached);
1364 spin_unlock_bh(&ul->lock);
1365 }
1366}
1367
1368void rt_flush_dev(struct net_device *dev)
1369{
1370 struct net *net = dev_net(dev);
1371 struct rtable *rt;
1372 int cpu;
1373
1374 for_each_possible_cpu(cpu) {
1375 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1376
1377 spin_lock_bh(&ul->lock);
1378 list_for_each_entry(rt, &ul->head, rt_uncached) {
1379 if (rt->dst.dev != dev)
1380 continue;
1381 rt->dst.dev = net->loopback_dev;
1382 dev_hold(rt->dst.dev);
1383 dev_put(dev);
1384 }
1385 spin_unlock_bh(&ul->lock);
1386 }
1387}
1388
1389static bool rt_cache_valid(const struct rtable *rt)
1390{
1391 return rt &&
1392 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1393 !rt_is_expired(rt);
1394}
1395
1396static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1397 const struct fib_result *res,
1398 struct fib_nh_exception *fnhe,
1399 struct fib_info *fi, u16 type, u32 itag)
1400{
1401 bool cached = false;
1402
1403 if (fi) {
1404 struct fib_nh *nh = &FIB_RES_NH(*res);
1405
1406 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1407 rt->rt_gateway = nh->nh_gw;
1408 rt->rt_uses_gateway = 1;
1409 }
1410 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
1411#ifdef CONFIG_IP_ROUTE_CLASSID
1412 rt->dst.tclassid = nh->nh_tclassid;
1413#endif
1414 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1415 if (unlikely(fnhe))
1416 cached = rt_bind_exception(rt, fnhe, daddr);
1417 else if (!(rt->dst.flags & DST_NOCACHE))
1418 cached = rt_cache_route(nh, rt);
1419 if (unlikely(!cached)) {
1420 /* Routes we intend to cache in nexthop exception or
1421 * FIB nexthop have the DST_NOCACHE bit clear.
1422 * However, if we are unsuccessful at storing this
1423 * route into the cache we really need to set it.
1424 */
1425 rt->dst.flags |= DST_NOCACHE;
1426 if (!rt->rt_gateway)
1427 rt->rt_gateway = daddr;
1428 rt_add_uncached_list(rt);
1429 }
1430 } else
1431 rt_add_uncached_list(rt);
1432
1433#ifdef CONFIG_IP_ROUTE_CLASSID
1434#ifdef CONFIG_IP_MULTIPLE_TABLES
1435 set_class_tag(rt, res->tclassid);
1436#endif
1437 set_class_tag(rt, itag);
1438#endif
1439}
1440
1441struct rtable *rt_dst_alloc(struct net_device *dev,
1442 unsigned int flags, u16 type,
1443 bool nopolicy, bool noxfrm, bool will_cache)
1444{
1445 struct rtable *rt;
1446
1447 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1448 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) |
1449 (nopolicy ? DST_NOPOLICY : 0) |
1450 (noxfrm ? DST_NOXFRM : 0));
1451
1452 if (rt) {
1453 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1454 rt->rt_flags = flags;
1455 rt->rt_type = type;
1456 rt->rt_is_input = 0;
1457 rt->rt_iif = 0;
1458 rt->rt_pmtu = 0;
1459 rt->rt_gateway = 0;
1460 rt->rt_uses_gateway = 0;
1461 rt->rt_table_id = 0;
1462 INIT_LIST_HEAD(&rt->rt_uncached);
1463
1464 rt->dst.output = ip_output;
1465 if (flags & RTCF_LOCAL)
1466 rt->dst.input = ip_local_deliver;
1467 }
1468
1469 return rt;
1470}
1471EXPORT_SYMBOL(rt_dst_alloc);
1472
1473/* called in rcu_read_lock() section */
1474static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1475 u8 tos, struct net_device *dev, int our)
1476{
1477 struct rtable *rth;
1478 struct in_device *in_dev = __in_dev_get_rcu(dev);
1479 unsigned int flags = RTCF_MULTICAST;
1480 u32 itag = 0;
1481 int err;
1482
1483 /* Primary sanity checks. */
1484
1485 if (!in_dev)
1486 return -EINVAL;
1487
1488 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1489 skb->protocol != htons(ETH_P_IP))
1490 goto e_inval;
1491
1492 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1493 goto e_inval;
1494
1495 if (ipv4_is_zeronet(saddr)) {
1496 if (!ipv4_is_local_multicast(daddr))
1497 goto e_inval;
1498 } else {
1499 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1500 in_dev, &itag);
1501 if (err < 0)
1502 goto e_err;
1503 }
1504 if (our)
1505 flags |= RTCF_LOCAL;
1506
1507 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1508 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1509 if (!rth)
1510 goto e_nobufs;
1511
1512#ifdef CONFIG_IP_ROUTE_CLASSID
1513 rth->dst.tclassid = itag;
1514#endif
1515 rth->dst.output = ip_rt_bug;
1516 rth->rt_is_input= 1;
1517
1518#ifdef CONFIG_IP_MROUTE
1519 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1520 rth->dst.input = ip_mr_input;
1521#endif
1522 RT_CACHE_STAT_INC(in_slow_mc);
1523
1524 skb_dst_set(skb, &rth->dst);
1525 return 0;
1526
1527e_nobufs:
1528 return -ENOBUFS;
1529e_inval:
1530 return -EINVAL;
1531e_err:
1532 return err;
1533}
1534
1535
1536static void ip_handle_martian_source(struct net_device *dev,
1537 struct in_device *in_dev,
1538 struct sk_buff *skb,
1539 __be32 daddr,
1540 __be32 saddr)
1541{
1542 RT_CACHE_STAT_INC(in_martian_src);
1543#ifdef CONFIG_IP_ROUTE_VERBOSE
1544 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1545 /*
1546 * RFC1812 recommendation, if source is martian,
1547 * the only hint is MAC header.
1548 */
1549 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1550 &daddr, &saddr, dev->name);
1551 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1552 print_hex_dump(KERN_WARNING, "ll header: ",
1553 DUMP_PREFIX_OFFSET, 16, 1,
1554 skb_mac_header(skb),
1555 dev->hard_header_len, true);
1556 }
1557 }
1558#endif
1559}
1560
1561static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1562{
1563 struct fnhe_hash_bucket *hash;
1564 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1565 u32 hval = fnhe_hashfun(daddr);
1566
1567 spin_lock_bh(&fnhe_lock);
1568
1569 hash = rcu_dereference_protected(nh->nh_exceptions,
1570 lockdep_is_held(&fnhe_lock));
1571 hash += hval;
1572
1573 fnhe_p = &hash->chain;
1574 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1575 while (fnhe) {
1576 if (fnhe->fnhe_daddr == daddr) {
1577 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1578 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1579 fnhe_flush_routes(fnhe);
1580 kfree_rcu(fnhe, rcu);
1581 break;
1582 }
1583 fnhe_p = &fnhe->fnhe_next;
1584 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1585 lockdep_is_held(&fnhe_lock));
1586 }
1587
1588 spin_unlock_bh(&fnhe_lock);
1589}
1590
1591/* called in rcu_read_lock() section */
1592static int __mkroute_input(struct sk_buff *skb,
1593 const struct fib_result *res,
1594 struct in_device *in_dev,
1595 __be32 daddr, __be32 saddr, u32 tos)
1596{
1597 struct fib_nh_exception *fnhe;
1598 struct rtable *rth;
1599 int err;
1600 struct in_device *out_dev;
1601 bool do_cache;
1602 u32 itag = 0;
1603
1604 /* get a working reference to the output device */
1605 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1606 if (!out_dev) {
1607 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1608 return -EINVAL;
1609 }
1610
1611 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1612 in_dev->dev, in_dev, &itag);
1613 if (err < 0) {
1614 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1615 saddr);
1616
1617 goto cleanup;
1618 }
1619
1620 do_cache = res->fi && !itag;
1621 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1622 skb->protocol == htons(ETH_P_IP) &&
1623 (IN_DEV_SHARED_MEDIA(out_dev) ||
1624 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1625 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1626
1627 if (skb->protocol != htons(ETH_P_IP)) {
1628 /* Not IP (i.e. ARP). Do not create route, if it is
1629 * invalid for proxy arp. DNAT routes are always valid.
1630 *
1631 * Proxy arp feature have been extended to allow, ARP
1632 * replies back to the same interface, to support
1633 * Private VLAN switch technologies. See arp.c.
1634 */
1635 if (out_dev == in_dev &&
1636 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1637 err = -EINVAL;
1638 goto cleanup;
1639 }
1640 }
1641
1642 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1643 if (do_cache) {
1644 if (fnhe) {
1645 rth = rcu_dereference(fnhe->fnhe_rth_input);
1646 if (rth && rth->dst.expires &&
1647 time_after(jiffies, rth->dst.expires)) {
1648 ip_del_fnhe(&FIB_RES_NH(*res), daddr);
1649 fnhe = NULL;
1650 } else {
1651 goto rt_cache;
1652 }
1653 }
1654
1655 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1656
1657rt_cache:
1658 if (rt_cache_valid(rth)) {
1659 skb_dst_set_noref(skb, &rth->dst);
1660 goto out;
1661 }
1662 }
1663
1664 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1665 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1666 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1667 if (!rth) {
1668 err = -ENOBUFS;
1669 goto cleanup;
1670 }
1671
1672 rth->rt_is_input = 1;
1673 if (res->table)
1674 rth->rt_table_id = res->table->tb_id;
1675 RT_CACHE_STAT_INC(in_slow_tot);
1676
1677 rth->dst.input = ip_forward;
1678
1679 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
1680 if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
1681 rth->dst.lwtstate->orig_output = rth->dst.output;
1682 rth->dst.output = lwtunnel_output;
1683 }
1684 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
1685 rth->dst.lwtstate->orig_input = rth->dst.input;
1686 rth->dst.input = lwtunnel_input;
1687 }
1688 skb_dst_set(skb, &rth->dst);
1689out:
1690 err = 0;
1691 cleanup:
1692 return err;
1693}
1694
1695#ifdef CONFIG_IP_ROUTE_MULTIPATH
1696
1697/* To make ICMP packets follow the right flow, the multipath hash is
1698 * calculated from the inner IP addresses in reverse order.
1699 */
1700static int ip_multipath_icmp_hash(struct sk_buff *skb)
1701{
1702 const struct iphdr *outer_iph = ip_hdr(skb);
1703 struct icmphdr _icmph;
1704 const struct icmphdr *icmph;
1705 struct iphdr _inner_iph;
1706 const struct iphdr *inner_iph;
1707
1708 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1709 goto standard_hash;
1710
1711 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1712 &_icmph);
1713 if (!icmph)
1714 goto standard_hash;
1715
1716 if (icmph->type != ICMP_DEST_UNREACH &&
1717 icmph->type != ICMP_REDIRECT &&
1718 icmph->type != ICMP_TIME_EXCEEDED &&
1719 icmph->type != ICMP_PARAMETERPROB) {
1720 goto standard_hash;
1721 }
1722
1723 inner_iph = skb_header_pointer(skb,
1724 outer_iph->ihl * 4 + sizeof(_icmph),
1725 sizeof(_inner_iph), &_inner_iph);
1726 if (!inner_iph)
1727 goto standard_hash;
1728
1729 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr);
1730
1731standard_hash:
1732 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr);
1733}
1734
1735#endif /* CONFIG_IP_ROUTE_MULTIPATH */
1736
1737static int ip_mkroute_input(struct sk_buff *skb,
1738 struct fib_result *res,
1739 const struct flowi4 *fl4,
1740 struct in_device *in_dev,
1741 __be32 daddr, __be32 saddr, u32 tos)
1742{
1743#ifdef CONFIG_IP_ROUTE_MULTIPATH
1744 if (res->fi && res->fi->fib_nhs > 1) {
1745 int h;
1746
1747 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
1748 h = ip_multipath_icmp_hash(skb);
1749 else
1750 h = fib_multipath_hash(saddr, daddr);
1751 fib_select_multipath(res, h);
1752 }
1753#endif
1754
1755 /* create a routing cache entry */
1756 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1757}
1758
1759/*
1760 * NOTE. We drop all the packets that has local source
1761 * addresses, because every properly looped back packet
1762 * must have correct destination already attached by output routine.
1763 *
1764 * Such approach solves two big problems:
1765 * 1. Not simplex devices are handled properly.
1766 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1767 * called with rcu_read_lock()
1768 */
1769
1770static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1771 u8 tos, struct net_device *dev)
1772{
1773 struct fib_result res;
1774 struct in_device *in_dev = __in_dev_get_rcu(dev);
1775 struct ip_tunnel_info *tun_info;
1776 struct flowi4 fl4;
1777 unsigned int flags = 0;
1778 u32 itag = 0;
1779 struct rtable *rth;
1780 int err = -EINVAL;
1781 struct net *net = dev_net(dev);
1782 bool do_cache;
1783
1784 /* IP on this device is disabled. */
1785
1786 if (!in_dev)
1787 goto out;
1788
1789 /* Check for the most weird martians, which can be not detected
1790 by fib_lookup.
1791 */
1792
1793 tun_info = skb_tunnel_info(skb);
1794 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1795 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1796 else
1797 fl4.flowi4_tun_key.tun_id = 0;
1798 skb_dst_drop(skb);
1799
1800 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1801 goto martian_source;
1802
1803 res.fi = NULL;
1804 res.table = NULL;
1805 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1806 goto brd_input;
1807
1808 /* Accept zero addresses only to limited broadcast;
1809 * I even do not know to fix it or not. Waiting for complains :-)
1810 */
1811 if (ipv4_is_zeronet(saddr))
1812 goto martian_source;
1813
1814 if (ipv4_is_zeronet(daddr))
1815 goto martian_destination;
1816
1817 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1818 * and call it once if daddr or/and saddr are loopback addresses
1819 */
1820 if (ipv4_is_loopback(daddr)) {
1821 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1822 goto martian_destination;
1823 } else if (ipv4_is_loopback(saddr)) {
1824 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1825 goto martian_source;
1826 }
1827
1828 /*
1829 * Now we are ready to route packet.
1830 */
1831 fl4.flowi4_oif = 0;
1832 fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev);
1833 fl4.flowi4_mark = skb->mark;
1834 fl4.flowi4_tos = tos;
1835 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1836 fl4.flowi4_flags = 0;
1837 fl4.daddr = daddr;
1838 fl4.saddr = saddr;
1839 err = fib_lookup(net, &fl4, &res, 0);
1840 if (err != 0) {
1841 if (!IN_DEV_FORWARD(in_dev))
1842 err = -EHOSTUNREACH;
1843 goto no_route;
1844 }
1845
1846 if (res.type == RTN_BROADCAST)
1847 goto brd_input;
1848
1849 if (res.type == RTN_LOCAL) {
1850 err = fib_validate_source(skb, saddr, daddr, tos,
1851 0, dev, in_dev, &itag);
1852 if (err < 0)
1853 goto martian_source;
1854 goto local_input;
1855 }
1856
1857 if (!IN_DEV_FORWARD(in_dev)) {
1858 err = -EHOSTUNREACH;
1859 goto no_route;
1860 }
1861 if (res.type != RTN_UNICAST)
1862 goto martian_destination;
1863
1864 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos);
1865out: return err;
1866
1867brd_input:
1868 if (skb->protocol != htons(ETH_P_IP))
1869 goto e_inval;
1870
1871 if (!ipv4_is_zeronet(saddr)) {
1872 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1873 in_dev, &itag);
1874 if (err < 0)
1875 goto martian_source;
1876 }
1877 flags |= RTCF_BROADCAST;
1878 res.type = RTN_BROADCAST;
1879 RT_CACHE_STAT_INC(in_brd);
1880
1881local_input:
1882 do_cache = false;
1883 if (res.fi) {
1884 if (!itag) {
1885 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
1886 if (rt_cache_valid(rth)) {
1887 skb_dst_set_noref(skb, &rth->dst);
1888 err = 0;
1889 goto out;
1890 }
1891 do_cache = true;
1892 }
1893 }
1894
1895 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type,
1896 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
1897 if (!rth)
1898 goto e_nobufs;
1899
1900 rth->dst.output= ip_rt_bug;
1901#ifdef CONFIG_IP_ROUTE_CLASSID
1902 rth->dst.tclassid = itag;
1903#endif
1904 rth->rt_is_input = 1;
1905 if (res.table)
1906 rth->rt_table_id = res.table->tb_id;
1907
1908 RT_CACHE_STAT_INC(in_slow_tot);
1909 if (res.type == RTN_UNREACHABLE) {
1910 rth->dst.input= ip_error;
1911 rth->dst.error= -err;
1912 rth->rt_flags &= ~RTCF_LOCAL;
1913 }
1914 if (do_cache) {
1915 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
1916 rth->dst.flags |= DST_NOCACHE;
1917 rt_add_uncached_list(rth);
1918 }
1919 }
1920 skb_dst_set(skb, &rth->dst);
1921 err = 0;
1922 goto out;
1923
1924no_route:
1925 RT_CACHE_STAT_INC(in_no_route);
1926 res.type = RTN_UNREACHABLE;
1927 res.fi = NULL;
1928 res.table = NULL;
1929 goto local_input;
1930
1931 /*
1932 * Do not cache martian addresses: they should be logged (RFC1812)
1933 */
1934martian_destination:
1935 RT_CACHE_STAT_INC(in_martian_dst);
1936#ifdef CONFIG_IP_ROUTE_VERBOSE
1937 if (IN_DEV_LOG_MARTIANS(in_dev))
1938 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
1939 &daddr, &saddr, dev->name);
1940#endif
1941
1942e_inval:
1943 err = -EINVAL;
1944 goto out;
1945
1946e_nobufs:
1947 err = -ENOBUFS;
1948 goto out;
1949
1950martian_source:
1951 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
1952 goto out;
1953}
1954
1955int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1956 u8 tos, struct net_device *dev)
1957{
1958 int res;
1959
1960 rcu_read_lock();
1961
1962 /* Multicast recognition logic is moved from route cache to here.
1963 The problem was that too many Ethernet cards have broken/missing
1964 hardware multicast filters :-( As result the host on multicasting
1965 network acquires a lot of useless route cache entries, sort of
1966 SDR messages from all the world. Now we try to get rid of them.
1967 Really, provided software IP multicast filter is organized
1968 reasonably (at least, hashed), it does not result in a slowdown
1969 comparing with route cache reject entries.
1970 Note, that multicast routers are not affected, because
1971 route cache entry is created eventually.
1972 */
1973 if (ipv4_is_multicast(daddr)) {
1974 struct in_device *in_dev = __in_dev_get_rcu(dev);
1975
1976 if (in_dev) {
1977 int our = ip_check_mc_rcu(in_dev, daddr, saddr,
1978 ip_hdr(skb)->protocol);
1979 if (our
1980#ifdef CONFIG_IP_MROUTE
1981 ||
1982 (!ipv4_is_local_multicast(daddr) &&
1983 IN_DEV_MFORWARD(in_dev))
1984#endif
1985 ) {
1986 int res = ip_route_input_mc(skb, daddr, saddr,
1987 tos, dev, our);
1988 rcu_read_unlock();
1989 return res;
1990 }
1991 }
1992 rcu_read_unlock();
1993 return -EINVAL;
1994 }
1995 res = ip_route_input_slow(skb, daddr, saddr, tos, dev);
1996 rcu_read_unlock();
1997 return res;
1998}
1999EXPORT_SYMBOL(ip_route_input_noref);
2000
2001/* called with rcu_read_lock() */
2002static struct rtable *__mkroute_output(const struct fib_result *res,
2003 const struct flowi4 *fl4, int orig_oif,
2004 struct net_device *dev_out,
2005 unsigned int flags)
2006{
2007 struct fib_info *fi = res->fi;
2008 struct fib_nh_exception *fnhe;
2009 struct in_device *in_dev;
2010 u16 type = res->type;
2011 struct rtable *rth;
2012 bool do_cache;
2013
2014 in_dev = __in_dev_get_rcu(dev_out);
2015 if (!in_dev)
2016 return ERR_PTR(-EINVAL);
2017
2018 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2019 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK))
2020 return ERR_PTR(-EINVAL);
2021
2022 if (ipv4_is_lbcast(fl4->daddr))
2023 type = RTN_BROADCAST;
2024 else if (ipv4_is_multicast(fl4->daddr))
2025 type = RTN_MULTICAST;
2026 else if (ipv4_is_zeronet(fl4->daddr))
2027 return ERR_PTR(-EINVAL);
2028
2029 if (dev_out->flags & IFF_LOOPBACK)
2030 flags |= RTCF_LOCAL;
2031
2032 do_cache = true;
2033 if (type == RTN_BROADCAST) {
2034 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2035 fi = NULL;
2036 } else if (type == RTN_MULTICAST) {
2037 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2038 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2039 fl4->flowi4_proto))
2040 flags &= ~RTCF_LOCAL;
2041 else
2042 do_cache = false;
2043 /* If multicast route do not exist use
2044 * default one, but do not gateway in this case.
2045 * Yes, it is hack.
2046 */
2047 if (fi && res->prefixlen < 4)
2048 fi = NULL;
2049 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2050 (orig_oif != dev_out->ifindex)) {
2051 /* For local routes that require a particular output interface
2052 * we do not want to cache the result. Caching the result
2053 * causes incorrect behaviour when there are multiple source
2054 * addresses on the interface, the end result being that if the
2055 * intended recipient is waiting on that interface for the
2056 * packet he won't receive it because it will be delivered on
2057 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2058 * be set to the loopback interface as well.
2059 */
2060 fi = NULL;
2061 }
2062
2063 fnhe = NULL;
2064 do_cache &= fi != NULL;
2065 if (do_cache) {
2066 struct rtable __rcu **prth;
2067 struct fib_nh *nh = &FIB_RES_NH(*res);
2068
2069 fnhe = find_exception(nh, fl4->daddr);
2070 if (fnhe) {
2071 prth = &fnhe->fnhe_rth_output;
2072 rth = rcu_dereference(*prth);
2073 if (rth && rth->dst.expires &&
2074 time_after(jiffies, rth->dst.expires)) {
2075 ip_del_fnhe(nh, fl4->daddr);
2076 fnhe = NULL;
2077 } else {
2078 goto rt_cache;
2079 }
2080 }
2081
2082 if (unlikely(fl4->flowi4_flags &
2083 FLOWI_FLAG_KNOWN_NH &&
2084 !(nh->nh_gw &&
2085 nh->nh_scope == RT_SCOPE_LINK))) {
2086 do_cache = false;
2087 goto add;
2088 }
2089 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2090 rth = rcu_dereference(*prth);
2091
2092rt_cache:
2093 if (rt_cache_valid(rth)) {
2094 dst_hold(&rth->dst);
2095 return rth;
2096 }
2097 }
2098
2099add:
2100 rth = rt_dst_alloc(dev_out, flags, type,
2101 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2102 IN_DEV_CONF_GET(in_dev, NOXFRM),
2103 do_cache);
2104 if (!rth)
2105 return ERR_PTR(-ENOBUFS);
2106
2107 rth->rt_iif = orig_oif ? : 0;
2108 if (res->table)
2109 rth->rt_table_id = res->table->tb_id;
2110
2111 RT_CACHE_STAT_INC(out_slow_tot);
2112
2113 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2114 if (flags & RTCF_LOCAL &&
2115 !(dev_out->flags & IFF_LOOPBACK)) {
2116 rth->dst.output = ip_mc_output;
2117 RT_CACHE_STAT_INC(out_slow_mc);
2118 }
2119#ifdef CONFIG_IP_MROUTE
2120 if (type == RTN_MULTICAST) {
2121 if (IN_DEV_MFORWARD(in_dev) &&
2122 !ipv4_is_local_multicast(fl4->daddr)) {
2123 rth->dst.input = ip_mr_input;
2124 rth->dst.output = ip_mc_output;
2125 }
2126 }
2127#endif
2128 }
2129
2130 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
2131 if (lwtunnel_output_redirect(rth->dst.lwtstate))
2132 rth->dst.output = lwtunnel_output;
2133
2134 return rth;
2135}
2136
2137/*
2138 * Major route resolver routine.
2139 */
2140
2141struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2142 int mp_hash)
2143{
2144 struct net_device *dev_out = NULL;
2145 __u8 tos = RT_FL_TOS(fl4);
2146 unsigned int flags = 0;
2147 struct fib_result res;
2148 struct rtable *rth;
2149 int orig_oif;
2150 int err = -ENETUNREACH;
2151
2152 res.tclassid = 0;
2153 res.fi = NULL;
2154 res.table = NULL;
2155
2156 orig_oif = fl4->flowi4_oif;
2157
2158 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2159 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2160 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2161 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2162
2163 rcu_read_lock();
2164 if (fl4->saddr) {
2165 rth = ERR_PTR(-EINVAL);
2166 if (ipv4_is_multicast(fl4->saddr) ||
2167 ipv4_is_lbcast(fl4->saddr) ||
2168 ipv4_is_zeronet(fl4->saddr))
2169 goto out;
2170
2171 /* I removed check for oif == dev_out->oif here.
2172 It was wrong for two reasons:
2173 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2174 is assigned to multiple interfaces.
2175 2. Moreover, we are allowed to send packets with saddr
2176 of another iface. --ANK
2177 */
2178
2179 if (fl4->flowi4_oif == 0 &&
2180 (ipv4_is_multicast(fl4->daddr) ||
2181 ipv4_is_lbcast(fl4->daddr))) {
2182 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2183 dev_out = __ip_dev_find(net, fl4->saddr, false);
2184 if (!dev_out)
2185 goto out;
2186
2187 /* Special hack: user can direct multicasts
2188 and limited broadcast via necessary interface
2189 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2190 This hack is not just for fun, it allows
2191 vic,vat and friends to work.
2192 They bind socket to loopback, set ttl to zero
2193 and expect that it will work.
2194 From the viewpoint of routing cache they are broken,
2195 because we are not allowed to build multicast path
2196 with loopback source addr (look, routing cache
2197 cannot know, that ttl is zero, so that packet
2198 will not leave this host and route is valid).
2199 Luckily, this hack is good workaround.
2200 */
2201
2202 fl4->flowi4_oif = dev_out->ifindex;
2203 goto make_route;
2204 }
2205
2206 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2207 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2208 if (!__ip_dev_find(net, fl4->saddr, false))
2209 goto out;
2210 }
2211 }
2212
2213
2214 if (fl4->flowi4_oif) {
2215 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2216 rth = ERR_PTR(-ENODEV);
2217 if (!dev_out)
2218 goto out;
2219
2220 /* RACE: Check return value of inet_select_addr instead. */
2221 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2222 rth = ERR_PTR(-ENETUNREACH);
2223 goto out;
2224 }
2225 if (ipv4_is_local_multicast(fl4->daddr) ||
2226 ipv4_is_lbcast(fl4->daddr) ||
2227 fl4->flowi4_proto == IPPROTO_IGMP) {
2228 if (!fl4->saddr)
2229 fl4->saddr = inet_select_addr(dev_out, 0,
2230 RT_SCOPE_LINK);
2231 goto make_route;
2232 }
2233 if (!fl4->saddr) {
2234 if (ipv4_is_multicast(fl4->daddr))
2235 fl4->saddr = inet_select_addr(dev_out, 0,
2236 fl4->flowi4_scope);
2237 else if (!fl4->daddr)
2238 fl4->saddr = inet_select_addr(dev_out, 0,
2239 RT_SCOPE_HOST);
2240 }
2241
2242 rth = l3mdev_get_rtable(dev_out, fl4);
2243 if (rth)
2244 goto out;
2245 }
2246
2247 if (!fl4->daddr) {
2248 fl4->daddr = fl4->saddr;
2249 if (!fl4->daddr)
2250 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2251 dev_out = net->loopback_dev;
2252 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2253 res.type = RTN_LOCAL;
2254 flags |= RTCF_LOCAL;
2255 goto make_route;
2256 }
2257
2258 err = fib_lookup(net, fl4, &res, 0);
2259 if (err) {
2260 res.fi = NULL;
2261 res.table = NULL;
2262 if (fl4->flowi4_oif &&
2263 !netif_index_is_l3_master(net, fl4->flowi4_oif)) {
2264 /* Apparently, routing tables are wrong. Assume,
2265 that the destination is on link.
2266
2267 WHY? DW.
2268 Because we are allowed to send to iface
2269 even if it has NO routes and NO assigned
2270 addresses. When oif is specified, routing
2271 tables are looked up with only one purpose:
2272 to catch if destination is gatewayed, rather than
2273 direct. Moreover, if MSG_DONTROUTE is set,
2274 we send packet, ignoring both routing tables
2275 and ifaddr state. --ANK
2276
2277
2278 We could make it even if oif is unknown,
2279 likely IPv6, but we do not.
2280 */
2281
2282 if (fl4->saddr == 0)
2283 fl4->saddr = inet_select_addr(dev_out, 0,
2284 RT_SCOPE_LINK);
2285 res.type = RTN_UNICAST;
2286 goto make_route;
2287 }
2288 rth = ERR_PTR(err);
2289 goto out;
2290 }
2291
2292 if (res.type == RTN_LOCAL) {
2293 if (!fl4->saddr) {
2294 if (res.fi->fib_prefsrc)
2295 fl4->saddr = res.fi->fib_prefsrc;
2296 else
2297 fl4->saddr = fl4->daddr;
2298 }
2299 dev_out = net->loopback_dev;
2300 fl4->flowi4_oif = dev_out->ifindex;
2301 flags |= RTCF_LOCAL;
2302 goto make_route;
2303 }
2304
2305 fib_select_path(net, &res, fl4, mp_hash);
2306
2307 dev_out = FIB_RES_DEV(res);
2308 fl4->flowi4_oif = dev_out->ifindex;
2309
2310
2311make_route:
2312 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags);
2313
2314out:
2315 rcu_read_unlock();
2316 return rth;
2317}
2318EXPORT_SYMBOL_GPL(__ip_route_output_key_hash);
2319
2320static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2321{
2322 return NULL;
2323}
2324
2325static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2326{
2327 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2328
2329 return mtu ? : dst->dev->mtu;
2330}
2331
2332static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2333 struct sk_buff *skb, u32 mtu)
2334{
2335}
2336
2337static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2338 struct sk_buff *skb)
2339{
2340}
2341
2342static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2343 unsigned long old)
2344{
2345 return NULL;
2346}
2347
2348static struct dst_ops ipv4_dst_blackhole_ops = {
2349 .family = AF_INET,
2350 .check = ipv4_blackhole_dst_check,
2351 .mtu = ipv4_blackhole_mtu,
2352 .default_advmss = ipv4_default_advmss,
2353 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2354 .redirect = ipv4_rt_blackhole_redirect,
2355 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2356 .neigh_lookup = ipv4_neigh_lookup,
2357};
2358
2359struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2360{
2361 struct rtable *ort = (struct rtable *) dst_orig;
2362 struct rtable *rt;
2363
2364 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
2365 if (rt) {
2366 struct dst_entry *new = &rt->dst;
2367
2368 new->__use = 1;
2369 new->input = dst_discard;
2370 new->output = dst_discard_out;
2371
2372 new->dev = ort->dst.dev;
2373 if (new->dev)
2374 dev_hold(new->dev);
2375
2376 rt->rt_is_input = ort->rt_is_input;
2377 rt->rt_iif = ort->rt_iif;
2378 rt->rt_pmtu = ort->rt_pmtu;
2379
2380 rt->rt_genid = rt_genid_ipv4(net);
2381 rt->rt_flags = ort->rt_flags;
2382 rt->rt_type = ort->rt_type;
2383 rt->rt_gateway = ort->rt_gateway;
2384 rt->rt_uses_gateway = ort->rt_uses_gateway;
2385
2386 INIT_LIST_HEAD(&rt->rt_uncached);
2387 dst_free(new);
2388 }
2389
2390 dst_release(dst_orig);
2391
2392 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2393}
2394
2395struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2396 const struct sock *sk)
2397{
2398 struct rtable *rt = __ip_route_output_key(net, flp4);
2399
2400 if (IS_ERR(rt))
2401 return rt;
2402
2403 if (flp4->flowi4_proto)
2404 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2405 flowi4_to_flowi(flp4),
2406 sk, 0);
2407
2408 return rt;
2409}
2410EXPORT_SYMBOL_GPL(ip_route_output_flow);
2411
2412static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2413 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2414 u32 seq, int event, int nowait, unsigned int flags)
2415{
2416 struct rtable *rt = skb_rtable(skb);
2417 struct rtmsg *r;
2418 struct nlmsghdr *nlh;
2419 unsigned long expires = 0;
2420 u32 error;
2421 u32 metrics[RTAX_MAX];
2422
2423 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
2424 if (!nlh)
2425 return -EMSGSIZE;
2426
2427 r = nlmsg_data(nlh);
2428 r->rtm_family = AF_INET;
2429 r->rtm_dst_len = 32;
2430 r->rtm_src_len = 0;
2431 r->rtm_tos = fl4->flowi4_tos;
2432 r->rtm_table = table_id;
2433 if (nla_put_u32(skb, RTA_TABLE, table_id))
2434 goto nla_put_failure;
2435 r->rtm_type = rt->rt_type;
2436 r->rtm_scope = RT_SCOPE_UNIVERSE;
2437 r->rtm_protocol = RTPROT_UNSPEC;
2438 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2439 if (rt->rt_flags & RTCF_NOTIFY)
2440 r->rtm_flags |= RTM_F_NOTIFY;
2441 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2442 r->rtm_flags |= RTCF_DOREDIRECT;
2443
2444 if (nla_put_in_addr(skb, RTA_DST, dst))
2445 goto nla_put_failure;
2446 if (src) {
2447 r->rtm_src_len = 32;
2448 if (nla_put_in_addr(skb, RTA_SRC, src))
2449 goto nla_put_failure;
2450 }
2451 if (rt->dst.dev &&
2452 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2453 goto nla_put_failure;
2454#ifdef CONFIG_IP_ROUTE_CLASSID
2455 if (rt->dst.tclassid &&
2456 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2457 goto nla_put_failure;
2458#endif
2459 if (!rt_is_input_route(rt) &&
2460 fl4->saddr != src) {
2461 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2462 goto nla_put_failure;
2463 }
2464 if (rt->rt_uses_gateway &&
2465 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2466 goto nla_put_failure;
2467
2468 expires = rt->dst.expires;
2469 if (expires) {
2470 unsigned long now = jiffies;
2471
2472 if (time_before(now, expires))
2473 expires -= now;
2474 else
2475 expires = 0;
2476 }
2477
2478 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2479 if (rt->rt_pmtu && expires)
2480 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2481 if (rtnetlink_put_metrics(skb, metrics) < 0)
2482 goto nla_put_failure;
2483
2484 if (fl4->flowi4_mark &&
2485 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2486 goto nla_put_failure;
2487
2488 error = rt->dst.error;
2489
2490 if (rt_is_input_route(rt)) {
2491#ifdef CONFIG_IP_MROUTE
2492 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2493 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2494 int err = ipmr_get_route(net, skb,
2495 fl4->saddr, fl4->daddr,
2496 r, nowait);
2497 if (err <= 0) {
2498 if (!nowait) {
2499 if (err == 0)
2500 return 0;
2501 goto nla_put_failure;
2502 } else {
2503 if (err == -EMSGSIZE)
2504 goto nla_put_failure;
2505 error = err;
2506 }
2507 }
2508 } else
2509#endif
2510 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2511 goto nla_put_failure;
2512 }
2513
2514 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2515 goto nla_put_failure;
2516
2517 nlmsg_end(skb, nlh);
2518 return 0;
2519
2520nla_put_failure:
2521 nlmsg_cancel(skb, nlh);
2522 return -EMSGSIZE;
2523}
2524
2525static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
2526{
2527 struct net *net = sock_net(in_skb->sk);
2528 struct rtmsg *rtm;
2529 struct nlattr *tb[RTA_MAX+1];
2530 struct rtable *rt = NULL;
2531 struct flowi4 fl4;
2532 __be32 dst = 0;
2533 __be32 src = 0;
2534 u32 iif;
2535 int err;
2536 int mark;
2537 struct sk_buff *skb;
2538 u32 table_id = RT_TABLE_MAIN;
2539
2540 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy);
2541 if (err < 0)
2542 goto errout;
2543
2544 rtm = nlmsg_data(nlh);
2545
2546 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2547 if (!skb) {
2548 err = -ENOBUFS;
2549 goto errout;
2550 }
2551
2552 /* Reserve room for dummy headers, this skb can pass
2553 through good chunk of routing engine.
2554 */
2555 skb_reset_mac_header(skb);
2556 skb_reset_network_header(skb);
2557
2558 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
2559 ip_hdr(skb)->protocol = IPPROTO_ICMP;
2560 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2561
2562 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2563 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2564 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2565 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2566
2567 memset(&fl4, 0, sizeof(fl4));
2568 fl4.daddr = dst;
2569 fl4.saddr = src;
2570 fl4.flowi4_tos = rtm->rtm_tos;
2571 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2572 fl4.flowi4_mark = mark;
2573
2574 if (netif_index_is_l3_master(net, fl4.flowi4_oif))
2575 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF;
2576
2577 if (iif) {
2578 struct net_device *dev;
2579
2580 dev = __dev_get_by_index(net, iif);
2581 if (!dev) {
2582 err = -ENODEV;
2583 goto errout_free;
2584 }
2585
2586 skb->protocol = htons(ETH_P_IP);
2587 skb->dev = dev;
2588 skb->mark = mark;
2589 local_bh_disable();
2590 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev);
2591 local_bh_enable();
2592
2593 rt = skb_rtable(skb);
2594 if (err == 0 && rt->dst.error)
2595 err = -rt->dst.error;
2596 } else {
2597 rt = ip_route_output_key(net, &fl4);
2598
2599 err = 0;
2600 if (IS_ERR(rt))
2601 err = PTR_ERR(rt);
2602 }
2603
2604 if (err)
2605 goto errout_free;
2606
2607 skb_dst_set(skb, &rt->dst);
2608 if (rtm->rtm_flags & RTM_F_NOTIFY)
2609 rt->rt_flags |= RTCF_NOTIFY;
2610
2611 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2612 table_id = rt->rt_table_id;
2613
2614 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2615 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2616 RTM_NEWROUTE, 0, 0);
2617 if (err < 0)
2618 goto errout_free;
2619
2620 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2621errout:
2622 return err;
2623
2624errout_free:
2625 kfree_skb(skb);
2626 goto errout;
2627}
2628
2629void ip_rt_multicast_event(struct in_device *in_dev)
2630{
2631 rt_cache_flush(dev_net(in_dev->dev));
2632}
2633
2634#ifdef CONFIG_SYSCTL
2635static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2636static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2637static int ip_rt_gc_elasticity __read_mostly = 8;
2638
2639static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2640 void __user *buffer,
2641 size_t *lenp, loff_t *ppos)
2642{
2643 struct net *net = (struct net *)__ctl->extra1;
2644
2645 if (write) {
2646 rt_cache_flush(net);
2647 fnhe_genid_bump(net);
2648 return 0;
2649 }
2650
2651 return -EINVAL;
2652}
2653
2654static struct ctl_table ipv4_route_table[] = {
2655 {
2656 .procname = "gc_thresh",
2657 .data = &ipv4_dst_ops.gc_thresh,
2658 .maxlen = sizeof(int),
2659 .mode = 0644,
2660 .proc_handler = proc_dointvec,
2661 },
2662 {
2663 .procname = "max_size",
2664 .data = &ip_rt_max_size,
2665 .maxlen = sizeof(int),
2666 .mode = 0644,
2667 .proc_handler = proc_dointvec,
2668 },
2669 {
2670 /* Deprecated. Use gc_min_interval_ms */
2671
2672 .procname = "gc_min_interval",
2673 .data = &ip_rt_gc_min_interval,
2674 .maxlen = sizeof(int),
2675 .mode = 0644,
2676 .proc_handler = proc_dointvec_jiffies,
2677 },
2678 {
2679 .procname = "gc_min_interval_ms",
2680 .data = &ip_rt_gc_min_interval,
2681 .maxlen = sizeof(int),
2682 .mode = 0644,
2683 .proc_handler = proc_dointvec_ms_jiffies,
2684 },
2685 {
2686 .procname = "gc_timeout",
2687 .data = &ip_rt_gc_timeout,
2688 .maxlen = sizeof(int),
2689 .mode = 0644,
2690 .proc_handler = proc_dointvec_jiffies,
2691 },
2692 {
2693 .procname = "gc_interval",
2694 .data = &ip_rt_gc_interval,
2695 .maxlen = sizeof(int),
2696 .mode = 0644,
2697 .proc_handler = proc_dointvec_jiffies,
2698 },
2699 {
2700 .procname = "redirect_load",
2701 .data = &ip_rt_redirect_load,
2702 .maxlen = sizeof(int),
2703 .mode = 0644,
2704 .proc_handler = proc_dointvec,
2705 },
2706 {
2707 .procname = "redirect_number",
2708 .data = &ip_rt_redirect_number,
2709 .maxlen = sizeof(int),
2710 .mode = 0644,
2711 .proc_handler = proc_dointvec,
2712 },
2713 {
2714 .procname = "redirect_silence",
2715 .data = &ip_rt_redirect_silence,
2716 .maxlen = sizeof(int),
2717 .mode = 0644,
2718 .proc_handler = proc_dointvec,
2719 },
2720 {
2721 .procname = "error_cost",
2722 .data = &ip_rt_error_cost,
2723 .maxlen = sizeof(int),
2724 .mode = 0644,
2725 .proc_handler = proc_dointvec,
2726 },
2727 {
2728 .procname = "error_burst",
2729 .data = &ip_rt_error_burst,
2730 .maxlen = sizeof(int),
2731 .mode = 0644,
2732 .proc_handler = proc_dointvec,
2733 },
2734 {
2735 .procname = "gc_elasticity",
2736 .data = &ip_rt_gc_elasticity,
2737 .maxlen = sizeof(int),
2738 .mode = 0644,
2739 .proc_handler = proc_dointvec,
2740 },
2741 {
2742 .procname = "mtu_expires",
2743 .data = &ip_rt_mtu_expires,
2744 .maxlen = sizeof(int),
2745 .mode = 0644,
2746 .proc_handler = proc_dointvec_jiffies,
2747 },
2748 {
2749 .procname = "min_pmtu",
2750 .data = &ip_rt_min_pmtu,
2751 .maxlen = sizeof(int),
2752 .mode = 0644,
2753 .proc_handler = proc_dointvec,
2754 },
2755 {
2756 .procname = "min_adv_mss",
2757 .data = &ip_rt_min_advmss,
2758 .maxlen = sizeof(int),
2759 .mode = 0644,
2760 .proc_handler = proc_dointvec,
2761 },
2762 { }
2763};
2764
2765static struct ctl_table ipv4_route_flush_table[] = {
2766 {
2767 .procname = "flush",
2768 .maxlen = sizeof(int),
2769 .mode = 0200,
2770 .proc_handler = ipv4_sysctl_rtcache_flush,
2771 },
2772 { },
2773};
2774
2775static __net_init int sysctl_route_net_init(struct net *net)
2776{
2777 struct ctl_table *tbl;
2778
2779 tbl = ipv4_route_flush_table;
2780 if (!net_eq(net, &init_net)) {
2781 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2782 if (!tbl)
2783 goto err_dup;
2784
2785 /* Don't export sysctls to unprivileged users */
2786 if (net->user_ns != &init_user_ns)
2787 tbl[0].procname = NULL;
2788 }
2789 tbl[0].extra1 = net;
2790
2791 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2792 if (!net->ipv4.route_hdr)
2793 goto err_reg;
2794 return 0;
2795
2796err_reg:
2797 if (tbl != ipv4_route_flush_table)
2798 kfree(tbl);
2799err_dup:
2800 return -ENOMEM;
2801}
2802
2803static __net_exit void sysctl_route_net_exit(struct net *net)
2804{
2805 struct ctl_table *tbl;
2806
2807 tbl = net->ipv4.route_hdr->ctl_table_arg;
2808 unregister_net_sysctl_table(net->ipv4.route_hdr);
2809 BUG_ON(tbl == ipv4_route_flush_table);
2810 kfree(tbl);
2811}
2812
2813static __net_initdata struct pernet_operations sysctl_route_ops = {
2814 .init = sysctl_route_net_init,
2815 .exit = sysctl_route_net_exit,
2816};
2817#endif
2818
2819static __net_init int rt_genid_init(struct net *net)
2820{
2821 atomic_set(&net->ipv4.rt_genid, 0);
2822 atomic_set(&net->fnhe_genid, 0);
2823 get_random_bytes(&net->ipv4.dev_addr_genid,
2824 sizeof(net->ipv4.dev_addr_genid));
2825 return 0;
2826}
2827
2828static __net_initdata struct pernet_operations rt_genid_ops = {
2829 .init = rt_genid_init,
2830};
2831
2832static int __net_init ipv4_inetpeer_init(struct net *net)
2833{
2834 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
2835
2836 if (!bp)
2837 return -ENOMEM;
2838 inet_peer_base_init(bp);
2839 net->ipv4.peers = bp;
2840 return 0;
2841}
2842
2843static void __net_exit ipv4_inetpeer_exit(struct net *net)
2844{
2845 struct inet_peer_base *bp = net->ipv4.peers;
2846
2847 net->ipv4.peers = NULL;
2848 inetpeer_invalidate_tree(bp);
2849 kfree(bp);
2850}
2851
2852static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
2853 .init = ipv4_inetpeer_init,
2854 .exit = ipv4_inetpeer_exit,
2855};
2856
2857#ifdef CONFIG_IP_ROUTE_CLASSID
2858struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
2859#endif /* CONFIG_IP_ROUTE_CLASSID */
2860
2861int __init ip_rt_init(void)
2862{
2863 int rc = 0;
2864 int cpu;
2865
2866 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
2867 if (!ip_idents)
2868 panic("IP: failed to allocate ip_idents\n");
2869
2870 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
2871
2872 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
2873 if (!ip_tstamps)
2874 panic("IP: failed to allocate ip_tstamps\n");
2875
2876 for_each_possible_cpu(cpu) {
2877 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
2878
2879 INIT_LIST_HEAD(&ul->head);
2880 spin_lock_init(&ul->lock);
2881 }
2882#ifdef CONFIG_IP_ROUTE_CLASSID
2883 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
2884 if (!ip_rt_acct)
2885 panic("IP: failed to allocate ip_rt_acct\n");
2886#endif
2887
2888 ipv4_dst_ops.kmem_cachep =
2889 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
2890 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2891
2892 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
2893
2894 if (dst_entries_init(&ipv4_dst_ops) < 0)
2895 panic("IP: failed to allocate ipv4_dst_ops counter\n");
2896
2897 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
2898 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
2899
2900 ipv4_dst_ops.gc_thresh = ~0;
2901 ip_rt_max_size = INT_MAX;
2902
2903 devinet_init();
2904 ip_fib_init();
2905
2906 if (ip_rt_proc_init())
2907 pr_err("Unable to create route proc files\n");
2908#ifdef CONFIG_XFRM
2909 xfrm_init();
2910 xfrm4_init();
2911#endif
2912 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
2913
2914#ifdef CONFIG_SYSCTL
2915 register_pernet_subsys(&sysctl_route_ops);
2916#endif
2917 register_pernet_subsys(&rt_genid_ops);
2918 register_pernet_subsys(&ipv4_inetpeer_ops);
2919 return rc;
2920}
2921
2922#ifdef CONFIG_SYSCTL
2923/*
2924 * We really need to sanitize the damn ipv4 init order, then all
2925 * this nonsense will go away.
2926 */
2927void __init ip_static_sysctl_init(void)
2928{
2929 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
2930}
2931#endif