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