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 peer->n_redirects = 0;
893 }
894
895 /* Too many ignored redirects; do not send anything
896 * set dst.rate_last to the last seen redirected packet.
897 */
898 if (peer->n_redirects >= ip_rt_redirect_number) {
899 peer->rate_last = jiffies;
900 goto out_put_peer;
901 }
902
903 /* Check for load limit; set rate_last to the latest sent
904 * redirect.
905 */
906 if (peer->rate_tokens == 0 ||
907 time_after(jiffies,
908 (peer->rate_last +
909 (ip_rt_redirect_load << peer->rate_tokens)))) {
910 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
911
912 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
913 peer->rate_last = jiffies;
914 ++peer->rate_tokens;
915 ++peer->n_redirects;
916#ifdef CONFIG_IP_ROUTE_VERBOSE
917 if (log_martians &&
918 peer->rate_tokens == ip_rt_redirect_number)
919 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
920 &ip_hdr(skb)->saddr, inet_iif(skb),
921 &ip_hdr(skb)->daddr, &gw);
922#endif
923 }
924out_put_peer:
925 inet_putpeer(peer);
926}
927
928static int ip_error(struct sk_buff *skb)
929{
930 struct rtable *rt = skb_rtable(skb);
931 struct net_device *dev = skb->dev;
932 struct in_device *in_dev;
933 struct inet_peer *peer;
934 unsigned long now;
935 struct net *net;
936 bool send;
937 int code;
938
939 if (netif_is_l3_master(skb->dev)) {
940 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
941 if (!dev)
942 goto out;
943 }
944
945 in_dev = __in_dev_get_rcu(dev);
946
947 /* IP on this device is disabled. */
948 if (!in_dev)
949 goto out;
950
951 net = dev_net(rt->dst.dev);
952 if (!IN_DEV_FORWARD(in_dev)) {
953 switch (rt->dst.error) {
954 case EHOSTUNREACH:
955 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
956 break;
957
958 case ENETUNREACH:
959 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
960 break;
961 }
962 goto out;
963 }
964
965 switch (rt->dst.error) {
966 case EINVAL:
967 default:
968 goto out;
969 case EHOSTUNREACH:
970 code = ICMP_HOST_UNREACH;
971 break;
972 case ENETUNREACH:
973 code = ICMP_NET_UNREACH;
974 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
975 break;
976 case EACCES:
977 code = ICMP_PKT_FILTERED;
978 break;
979 }
980
981 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
982 l3mdev_master_ifindex(skb->dev), 1);
983
984 send = true;
985 if (peer) {
986 now = jiffies;
987 peer->rate_tokens += now - peer->rate_last;
988 if (peer->rate_tokens > ip_rt_error_burst)
989 peer->rate_tokens = ip_rt_error_burst;
990 peer->rate_last = now;
991 if (peer->rate_tokens >= ip_rt_error_cost)
992 peer->rate_tokens -= ip_rt_error_cost;
993 else
994 send = false;
995 inet_putpeer(peer);
996 }
997 if (send)
998 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
999
1000out: kfree_skb(skb);
1001 return 0;
1002}
1003
1004static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1005{
1006 struct dst_entry *dst = &rt->dst;
1007 u32 old_mtu = ipv4_mtu(dst);
1008 struct fib_result res;
1009 bool lock = false;
1010
1011 if (ip_mtu_locked(dst))
1012 return;
1013
1014 if (old_mtu < mtu)
1015 return;
1016
1017 if (mtu < ip_rt_min_pmtu) {
1018 lock = true;
1019 mtu = min(old_mtu, ip_rt_min_pmtu);
1020 }
1021
1022 if (rt->rt_pmtu == mtu && !lock &&
1023 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1024 return;
1025
1026 rcu_read_lock();
1027 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1028 struct fib_nh *nh = &FIB_RES_NH(res);
1029
1030 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock,
1031 jiffies + ip_rt_mtu_expires);
1032 }
1033 rcu_read_unlock();
1034}
1035
1036static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1037 struct sk_buff *skb, u32 mtu)
1038{
1039 struct rtable *rt = (struct rtable *) dst;
1040 struct flowi4 fl4;
1041
1042 ip_rt_build_flow_key(&fl4, sk, skb);
1043 __ip_rt_update_pmtu(rt, &fl4, mtu);
1044}
1045
1046void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1047 int oif, u8 protocol)
1048{
1049 const struct iphdr *iph = (const struct iphdr *) skb->data;
1050 struct flowi4 fl4;
1051 struct rtable *rt;
1052 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1053
1054 __build_flow_key(net, &fl4, NULL, iph, oif,
1055 RT_TOS(iph->tos), protocol, mark, 0);
1056 rt = __ip_route_output_key(net, &fl4);
1057 if (!IS_ERR(rt)) {
1058 __ip_rt_update_pmtu(rt, &fl4, mtu);
1059 ip_rt_put(rt);
1060 }
1061}
1062EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1063
1064static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1065{
1066 const struct iphdr *iph = (const struct iphdr *) skb->data;
1067 struct flowi4 fl4;
1068 struct rtable *rt;
1069
1070 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1071
1072 if (!fl4.flowi4_mark)
1073 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1074
1075 rt = __ip_route_output_key(sock_net(sk), &fl4);
1076 if (!IS_ERR(rt)) {
1077 __ip_rt_update_pmtu(rt, &fl4, mtu);
1078 ip_rt_put(rt);
1079 }
1080}
1081
1082void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1083{
1084 const struct iphdr *iph = (const struct iphdr *) skb->data;
1085 struct flowi4 fl4;
1086 struct rtable *rt;
1087 struct dst_entry *odst = NULL;
1088 bool new = false;
1089 struct net *net = sock_net(sk);
1090
1091 bh_lock_sock(sk);
1092
1093 if (!ip_sk_accept_pmtu(sk))
1094 goto out;
1095
1096 odst = sk_dst_get(sk);
1097
1098 if (sock_owned_by_user(sk) || !odst) {
1099 __ipv4_sk_update_pmtu(skb, sk, mtu);
1100 goto out;
1101 }
1102
1103 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1104
1105 rt = (struct rtable *)odst;
1106 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1107 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1108 if (IS_ERR(rt))
1109 goto out;
1110
1111 new = true;
1112 }
1113
1114 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1115
1116 if (!dst_check(&rt->dst, 0)) {
1117 if (new)
1118 dst_release(&rt->dst);
1119
1120 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1121 if (IS_ERR(rt))
1122 goto out;
1123
1124 new = true;
1125 }
1126
1127 if (new)
1128 sk_dst_set(sk, &rt->dst);
1129
1130out:
1131 bh_unlock_sock(sk);
1132 dst_release(odst);
1133}
1134EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1135
1136void ipv4_redirect(struct sk_buff *skb, struct net *net,
1137 int oif, u8 protocol)
1138{
1139 const struct iphdr *iph = (const struct iphdr *) skb->data;
1140 struct flowi4 fl4;
1141 struct rtable *rt;
1142
1143 __build_flow_key(net, &fl4, NULL, iph, oif,
1144 RT_TOS(iph->tos), protocol, 0, 0);
1145 rt = __ip_route_output_key(net, &fl4);
1146 if (!IS_ERR(rt)) {
1147 __ip_do_redirect(rt, skb, &fl4, false);
1148 ip_rt_put(rt);
1149 }
1150}
1151EXPORT_SYMBOL_GPL(ipv4_redirect);
1152
1153void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1154{
1155 const struct iphdr *iph = (const struct iphdr *) skb->data;
1156 struct flowi4 fl4;
1157 struct rtable *rt;
1158 struct net *net = sock_net(sk);
1159
1160 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1161 rt = __ip_route_output_key(net, &fl4);
1162 if (!IS_ERR(rt)) {
1163 __ip_do_redirect(rt, skb, &fl4, false);
1164 ip_rt_put(rt);
1165 }
1166}
1167EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1168
1169static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1170{
1171 struct rtable *rt = (struct rtable *) dst;
1172
1173 /* All IPV4 dsts are created with ->obsolete set to the value
1174 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1175 * into this function always.
1176 *
1177 * When a PMTU/redirect information update invalidates a route,
1178 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1179 * DST_OBSOLETE_DEAD by dst_free().
1180 */
1181 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1182 return NULL;
1183 return dst;
1184}
1185
1186static void ipv4_link_failure(struct sk_buff *skb)
1187{
1188 struct rtable *rt;
1189
1190 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1191
1192 rt = skb_rtable(skb);
1193 if (rt)
1194 dst_set_expires(&rt->dst, 0);
1195}
1196
1197static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1198{
1199 pr_debug("%s: %pI4 -> %pI4, %s\n",
1200 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1201 skb->dev ? skb->dev->name : "?");
1202 kfree_skb(skb);
1203 WARN_ON(1);
1204 return 0;
1205}
1206
1207/*
1208 We do not cache source address of outgoing interface,
1209 because it is used only by IP RR, TS and SRR options,
1210 so that it out of fast path.
1211
1212 BTW remember: "addr" is allowed to be not aligned
1213 in IP options!
1214 */
1215
1216void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1217{
1218 __be32 src;
1219
1220 if (rt_is_output_route(rt))
1221 src = ip_hdr(skb)->saddr;
1222 else {
1223 struct fib_result res;
1224 struct iphdr *iph = ip_hdr(skb);
1225 struct flowi4 fl4 = {
1226 .daddr = iph->daddr,
1227 .saddr = iph->saddr,
1228 .flowi4_tos = RT_TOS(iph->tos),
1229 .flowi4_oif = rt->dst.dev->ifindex,
1230 .flowi4_iif = skb->dev->ifindex,
1231 .flowi4_mark = skb->mark,
1232 };
1233
1234 rcu_read_lock();
1235 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1236 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1237 else
1238 src = inet_select_addr(rt->dst.dev,
1239 rt_nexthop(rt, iph->daddr),
1240 RT_SCOPE_UNIVERSE);
1241 rcu_read_unlock();
1242 }
1243 memcpy(addr, &src, 4);
1244}
1245
1246#ifdef CONFIG_IP_ROUTE_CLASSID
1247static void set_class_tag(struct rtable *rt, u32 tag)
1248{
1249 if (!(rt->dst.tclassid & 0xFFFF))
1250 rt->dst.tclassid |= tag & 0xFFFF;
1251 if (!(rt->dst.tclassid & 0xFFFF0000))
1252 rt->dst.tclassid |= tag & 0xFFFF0000;
1253}
1254#endif
1255
1256static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1257{
1258 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1259 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1260 ip_rt_min_advmss);
1261
1262 return min(advmss, IPV4_MAX_PMTU - header_size);
1263}
1264
1265static unsigned int ipv4_mtu(const struct dst_entry *dst)
1266{
1267 const struct rtable *rt = (const struct rtable *) dst;
1268 unsigned int mtu = rt->rt_pmtu;
1269
1270 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1271 mtu = dst_metric_raw(dst, RTAX_MTU);
1272
1273 if (mtu)
1274 return mtu;
1275
1276 mtu = READ_ONCE(dst->dev->mtu);
1277
1278 if (unlikely(ip_mtu_locked(dst))) {
1279 if (rt->rt_uses_gateway && mtu > 576)
1280 mtu = 576;
1281 }
1282
1283 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1284
1285 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1286}
1287
1288static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1289{
1290 struct fnhe_hash_bucket *hash;
1291 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1292 u32 hval = fnhe_hashfun(daddr);
1293
1294 spin_lock_bh(&fnhe_lock);
1295
1296 hash = rcu_dereference_protected(nh->nh_exceptions,
1297 lockdep_is_held(&fnhe_lock));
1298 hash += hval;
1299
1300 fnhe_p = &hash->chain;
1301 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1302 while (fnhe) {
1303 if (fnhe->fnhe_daddr == daddr) {
1304 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1305 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1306 /* set fnhe_daddr to 0 to ensure it won't bind with
1307 * new dsts in rt_bind_exception().
1308 */
1309 fnhe->fnhe_daddr = 0;
1310 fnhe_flush_routes(fnhe);
1311 kfree_rcu(fnhe, rcu);
1312 break;
1313 }
1314 fnhe_p = &fnhe->fnhe_next;
1315 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1316 lockdep_is_held(&fnhe_lock));
1317 }
1318
1319 spin_unlock_bh(&fnhe_lock);
1320}
1321
1322static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1323{
1324 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1325 struct fib_nh_exception *fnhe;
1326 u32 hval;
1327
1328 if (!hash)
1329 return NULL;
1330
1331 hval = fnhe_hashfun(daddr);
1332
1333 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1334 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1335 if (fnhe->fnhe_daddr == daddr) {
1336 if (fnhe->fnhe_expires &&
1337 time_after(jiffies, fnhe->fnhe_expires)) {
1338 ip_del_fnhe(nh, daddr);
1339 break;
1340 }
1341 return fnhe;
1342 }
1343 }
1344 return NULL;
1345}
1346
1347/* MTU selection:
1348 * 1. mtu on route is locked - use it
1349 * 2. mtu from nexthop exception
1350 * 3. mtu from egress device
1351 */
1352
1353u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1354{
1355 struct fib_info *fi = res->fi;
1356 struct fib_nh *nh = &fi->fib_nh[res->nh_sel];
1357 struct net_device *dev = nh->nh_dev;
1358 u32 mtu = 0;
1359
1360 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1361 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1362 mtu = fi->fib_mtu;
1363
1364 if (likely(!mtu)) {
1365 struct fib_nh_exception *fnhe;
1366
1367 fnhe = find_exception(nh, daddr);
1368 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1369 mtu = fnhe->fnhe_pmtu;
1370 }
1371
1372 if (likely(!mtu))
1373 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1374
1375 return mtu - lwtunnel_headroom(nh->nh_lwtstate, mtu);
1376}
1377
1378static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1379 __be32 daddr, const bool do_cache)
1380{
1381 bool ret = false;
1382
1383 spin_lock_bh(&fnhe_lock);
1384
1385 if (daddr == fnhe->fnhe_daddr) {
1386 struct rtable __rcu **porig;
1387 struct rtable *orig;
1388 int genid = fnhe_genid(dev_net(rt->dst.dev));
1389
1390 if (rt_is_input_route(rt))
1391 porig = &fnhe->fnhe_rth_input;
1392 else
1393 porig = &fnhe->fnhe_rth_output;
1394 orig = rcu_dereference(*porig);
1395
1396 if (fnhe->fnhe_genid != genid) {
1397 fnhe->fnhe_genid = genid;
1398 fnhe->fnhe_gw = 0;
1399 fnhe->fnhe_pmtu = 0;
1400 fnhe->fnhe_expires = 0;
1401 fnhe->fnhe_mtu_locked = false;
1402 fnhe_flush_routes(fnhe);
1403 orig = NULL;
1404 }
1405 fill_route_from_fnhe(rt, fnhe);
1406 if (!rt->rt_gateway)
1407 rt->rt_gateway = daddr;
1408
1409 if (do_cache) {
1410 dst_hold(&rt->dst);
1411 rcu_assign_pointer(*porig, rt);
1412 if (orig) {
1413 dst_dev_put(&orig->dst);
1414 dst_release(&orig->dst);
1415 }
1416 ret = true;
1417 }
1418
1419 fnhe->fnhe_stamp = jiffies;
1420 }
1421 spin_unlock_bh(&fnhe_lock);
1422
1423 return ret;
1424}
1425
1426static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1427{
1428 struct rtable *orig, *prev, **p;
1429 bool ret = true;
1430
1431 if (rt_is_input_route(rt)) {
1432 p = (struct rtable **)&nh->nh_rth_input;
1433 } else {
1434 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1435 }
1436 orig = *p;
1437
1438 /* hold dst before doing cmpxchg() to avoid race condition
1439 * on this dst
1440 */
1441 dst_hold(&rt->dst);
1442 prev = cmpxchg(p, orig, rt);
1443 if (prev == orig) {
1444 if (orig) {
1445 dst_dev_put(&orig->dst);
1446 dst_release(&orig->dst);
1447 }
1448 } else {
1449 dst_release(&rt->dst);
1450 ret = false;
1451 }
1452
1453 return ret;
1454}
1455
1456struct uncached_list {
1457 spinlock_t lock;
1458 struct list_head head;
1459};
1460
1461static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1462
1463void rt_add_uncached_list(struct rtable *rt)
1464{
1465 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1466
1467 rt->rt_uncached_list = ul;
1468
1469 spin_lock_bh(&ul->lock);
1470 list_add_tail(&rt->rt_uncached, &ul->head);
1471 spin_unlock_bh(&ul->lock);
1472}
1473
1474void rt_del_uncached_list(struct rtable *rt)
1475{
1476 if (!list_empty(&rt->rt_uncached)) {
1477 struct uncached_list *ul = rt->rt_uncached_list;
1478
1479 spin_lock_bh(&ul->lock);
1480 list_del(&rt->rt_uncached);
1481 spin_unlock_bh(&ul->lock);
1482 }
1483}
1484
1485static void ipv4_dst_destroy(struct dst_entry *dst)
1486{
1487 struct rtable *rt = (struct rtable *)dst;
1488
1489 ip_dst_metrics_put(dst);
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 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1537
1538#ifdef CONFIG_IP_ROUTE_CLASSID
1539 rt->dst.tclassid = nh->nh_tclassid;
1540#endif
1541 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1542 if (unlikely(fnhe))
1543 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1544 else if (do_cache)
1545 cached = rt_cache_route(nh, rt);
1546 if (unlikely(!cached)) {
1547 /* Routes we intend to cache in nexthop exception or
1548 * FIB nexthop have the DST_NOCACHE bit clear.
1549 * However, if we are unsuccessful at storing this
1550 * route into the cache we really need to set it.
1551 */
1552 if (!rt->rt_gateway)
1553 rt->rt_gateway = daddr;
1554 rt_add_uncached_list(rt);
1555 }
1556 } else
1557 rt_add_uncached_list(rt);
1558
1559#ifdef CONFIG_IP_ROUTE_CLASSID
1560#ifdef CONFIG_IP_MULTIPLE_TABLES
1561 set_class_tag(rt, res->tclassid);
1562#endif
1563 set_class_tag(rt, itag);
1564#endif
1565}
1566
1567struct rtable *rt_dst_alloc(struct net_device *dev,
1568 unsigned int flags, u16 type,
1569 bool nopolicy, bool noxfrm, bool will_cache)
1570{
1571 struct rtable *rt;
1572
1573 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1574 (will_cache ? 0 : DST_HOST) |
1575 (nopolicy ? DST_NOPOLICY : 0) |
1576 (noxfrm ? DST_NOXFRM : 0));
1577
1578 if (rt) {
1579 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1580 rt->rt_flags = flags;
1581 rt->rt_type = type;
1582 rt->rt_is_input = 0;
1583 rt->rt_iif = 0;
1584 rt->rt_pmtu = 0;
1585 rt->rt_mtu_locked = 0;
1586 rt->rt_gateway = 0;
1587 rt->rt_uses_gateway = 0;
1588 INIT_LIST_HEAD(&rt->rt_uncached);
1589
1590 rt->dst.output = ip_output;
1591 if (flags & RTCF_LOCAL)
1592 rt->dst.input = ip_local_deliver;
1593 }
1594
1595 return rt;
1596}
1597EXPORT_SYMBOL(rt_dst_alloc);
1598
1599/* called in rcu_read_lock() section */
1600int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1601 u8 tos, struct net_device *dev,
1602 struct in_device *in_dev, u32 *itag)
1603{
1604 int err;
1605
1606 /* Primary sanity checks. */
1607 if (!in_dev)
1608 return -EINVAL;
1609
1610 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1611 skb->protocol != htons(ETH_P_IP))
1612 return -EINVAL;
1613
1614 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1615 return -EINVAL;
1616
1617 if (ipv4_is_zeronet(saddr)) {
1618 if (!ipv4_is_local_multicast(daddr) &&
1619 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1620 return -EINVAL;
1621 } else {
1622 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1623 in_dev, itag);
1624 if (err < 0)
1625 return err;
1626 }
1627 return 0;
1628}
1629
1630/* called in rcu_read_lock() section */
1631static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1632 u8 tos, struct net_device *dev, int our)
1633{
1634 struct in_device *in_dev = __in_dev_get_rcu(dev);
1635 unsigned int flags = RTCF_MULTICAST;
1636 struct rtable *rth;
1637 u32 itag = 0;
1638 int err;
1639
1640 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1641 if (err)
1642 return err;
1643
1644 if (our)
1645 flags |= RTCF_LOCAL;
1646
1647 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1648 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1649 if (!rth)
1650 return -ENOBUFS;
1651
1652#ifdef CONFIG_IP_ROUTE_CLASSID
1653 rth->dst.tclassid = itag;
1654#endif
1655 rth->dst.output = ip_rt_bug;
1656 rth->rt_is_input= 1;
1657
1658#ifdef CONFIG_IP_MROUTE
1659 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1660 rth->dst.input = ip_mr_input;
1661#endif
1662 RT_CACHE_STAT_INC(in_slow_mc);
1663
1664 skb_dst_set(skb, &rth->dst);
1665 return 0;
1666}
1667
1668
1669static void ip_handle_martian_source(struct net_device *dev,
1670 struct in_device *in_dev,
1671 struct sk_buff *skb,
1672 __be32 daddr,
1673 __be32 saddr)
1674{
1675 RT_CACHE_STAT_INC(in_martian_src);
1676#ifdef CONFIG_IP_ROUTE_VERBOSE
1677 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1678 /*
1679 * RFC1812 recommendation, if source is martian,
1680 * the only hint is MAC header.
1681 */
1682 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1683 &daddr, &saddr, dev->name);
1684 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1685 print_hex_dump(KERN_WARNING, "ll header: ",
1686 DUMP_PREFIX_OFFSET, 16, 1,
1687 skb_mac_header(skb),
1688 dev->hard_header_len, false);
1689 }
1690 }
1691#endif
1692}
1693
1694/* called in rcu_read_lock() section */
1695static int __mkroute_input(struct sk_buff *skb,
1696 const struct fib_result *res,
1697 struct in_device *in_dev,
1698 __be32 daddr, __be32 saddr, u32 tos)
1699{
1700 struct fib_nh_exception *fnhe;
1701 struct rtable *rth;
1702 int err;
1703 struct in_device *out_dev;
1704 bool do_cache;
1705 u32 itag = 0;
1706
1707 /* get a working reference to the output device */
1708 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1709 if (!out_dev) {
1710 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1711 return -EINVAL;
1712 }
1713
1714 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1715 in_dev->dev, in_dev, &itag);
1716 if (err < 0) {
1717 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1718 saddr);
1719
1720 goto cleanup;
1721 }
1722
1723 do_cache = res->fi && !itag;
1724 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1725 skb->protocol == htons(ETH_P_IP) &&
1726 (IN_DEV_SHARED_MEDIA(out_dev) ||
1727 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1728 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1729
1730 if (skb->protocol != htons(ETH_P_IP)) {
1731 /* Not IP (i.e. ARP). Do not create route, if it is
1732 * invalid for proxy arp. DNAT routes are always valid.
1733 *
1734 * Proxy arp feature have been extended to allow, ARP
1735 * replies back to the same interface, to support
1736 * Private VLAN switch technologies. See arp.c.
1737 */
1738 if (out_dev == in_dev &&
1739 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1740 err = -EINVAL;
1741 goto cleanup;
1742 }
1743 }
1744
1745 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1746 if (do_cache) {
1747 if (fnhe)
1748 rth = rcu_dereference(fnhe->fnhe_rth_input);
1749 else
1750 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1751 if (rt_cache_valid(rth)) {
1752 skb_dst_set_noref(skb, &rth->dst);
1753 goto out;
1754 }
1755 }
1756
1757 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1758 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1759 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1760 if (!rth) {
1761 err = -ENOBUFS;
1762 goto cleanup;
1763 }
1764
1765 rth->rt_is_input = 1;
1766 RT_CACHE_STAT_INC(in_slow_tot);
1767
1768 rth->dst.input = ip_forward;
1769
1770 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1771 do_cache);
1772 lwtunnel_set_redirect(&rth->dst);
1773 skb_dst_set(skb, &rth->dst);
1774out:
1775 err = 0;
1776 cleanup:
1777 return err;
1778}
1779
1780#ifdef CONFIG_IP_ROUTE_MULTIPATH
1781/* To make ICMP packets follow the right flow, the multipath hash is
1782 * calculated from the inner IP addresses.
1783 */
1784static void ip_multipath_l3_keys(const struct sk_buff *skb,
1785 struct flow_keys *hash_keys)
1786{
1787 const struct iphdr *outer_iph = ip_hdr(skb);
1788 const struct iphdr *key_iph = outer_iph;
1789 const struct iphdr *inner_iph;
1790 const struct icmphdr *icmph;
1791 struct iphdr _inner_iph;
1792 struct icmphdr _icmph;
1793
1794 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1795 goto out;
1796
1797 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1798 goto out;
1799
1800 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1801 &_icmph);
1802 if (!icmph)
1803 goto out;
1804
1805 if (icmph->type != ICMP_DEST_UNREACH &&
1806 icmph->type != ICMP_REDIRECT &&
1807 icmph->type != ICMP_TIME_EXCEEDED &&
1808 icmph->type != ICMP_PARAMETERPROB)
1809 goto out;
1810
1811 inner_iph = skb_header_pointer(skb,
1812 outer_iph->ihl * 4 + sizeof(_icmph),
1813 sizeof(_inner_iph), &_inner_iph);
1814 if (!inner_iph)
1815 goto out;
1816
1817 key_iph = inner_iph;
1818out:
1819 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1820 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1821}
1822
1823/* if skb is set it will be used and fl4 can be NULL */
1824int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1825 const struct sk_buff *skb, struct flow_keys *flkeys)
1826{
1827 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
1828 struct flow_keys hash_keys;
1829 u32 mhash;
1830
1831 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1832 case 0:
1833 memset(&hash_keys, 0, sizeof(hash_keys));
1834 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1835 if (skb) {
1836 ip_multipath_l3_keys(skb, &hash_keys);
1837 } else {
1838 hash_keys.addrs.v4addrs.src = fl4->saddr;
1839 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1840 }
1841 break;
1842 case 1:
1843 /* skb is currently provided only when forwarding */
1844 if (skb) {
1845 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1846 struct flow_keys keys;
1847
1848 /* short-circuit if we already have L4 hash present */
1849 if (skb->l4_hash)
1850 return skb_get_hash_raw(skb) >> 1;
1851
1852 memset(&hash_keys, 0, sizeof(hash_keys));
1853
1854 if (!flkeys) {
1855 skb_flow_dissect_flow_keys(skb, &keys, flag);
1856 flkeys = &keys;
1857 }
1858
1859 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1860 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1861 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1862 hash_keys.ports.src = flkeys->ports.src;
1863 hash_keys.ports.dst = flkeys->ports.dst;
1864 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1865 } else {
1866 memset(&hash_keys, 0, sizeof(hash_keys));
1867 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1868 hash_keys.addrs.v4addrs.src = fl4->saddr;
1869 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1870 hash_keys.ports.src = fl4->fl4_sport;
1871 hash_keys.ports.dst = fl4->fl4_dport;
1872 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1873 }
1874 break;
1875 }
1876 mhash = flow_hash_from_keys(&hash_keys);
1877
1878 if (multipath_hash)
1879 mhash = jhash_2words(mhash, multipath_hash, 0);
1880
1881 return mhash >> 1;
1882}
1883#endif /* CONFIG_IP_ROUTE_MULTIPATH */
1884
1885static int ip_mkroute_input(struct sk_buff *skb,
1886 struct fib_result *res,
1887 struct in_device *in_dev,
1888 __be32 daddr, __be32 saddr, u32 tos,
1889 struct flow_keys *hkeys)
1890{
1891#ifdef CONFIG_IP_ROUTE_MULTIPATH
1892 if (res->fi && res->fi->fib_nhs > 1) {
1893 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
1894
1895 fib_select_multipath(res, h);
1896 }
1897#endif
1898
1899 /* create a routing cache entry */
1900 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1901}
1902
1903/*
1904 * NOTE. We drop all the packets that has local source
1905 * addresses, because every properly looped back packet
1906 * must have correct destination already attached by output routine.
1907 *
1908 * Such approach solves two big problems:
1909 * 1. Not simplex devices are handled properly.
1910 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1911 * called with rcu_read_lock()
1912 */
1913
1914static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1915 u8 tos, struct net_device *dev,
1916 struct fib_result *res)
1917{
1918 struct in_device *in_dev = __in_dev_get_rcu(dev);
1919 struct flow_keys *flkeys = NULL, _flkeys;
1920 struct net *net = dev_net(dev);
1921 struct ip_tunnel_info *tun_info;
1922 int err = -EINVAL;
1923 unsigned int flags = 0;
1924 u32 itag = 0;
1925 struct rtable *rth;
1926 struct flowi4 fl4;
1927 bool do_cache;
1928
1929 /* IP on this device is disabled. */
1930
1931 if (!in_dev)
1932 goto out;
1933
1934 /* Check for the most weird martians, which can be not detected
1935 by fib_lookup.
1936 */
1937
1938 tun_info = skb_tunnel_info(skb);
1939 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1940 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1941 else
1942 fl4.flowi4_tun_key.tun_id = 0;
1943 skb_dst_drop(skb);
1944
1945 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1946 goto martian_source;
1947
1948 res->fi = NULL;
1949 res->table = NULL;
1950 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1951 goto brd_input;
1952
1953 /* Accept zero addresses only to limited broadcast;
1954 * I even do not know to fix it or not. Waiting for complains :-)
1955 */
1956 if (ipv4_is_zeronet(saddr))
1957 goto martian_source;
1958
1959 if (ipv4_is_zeronet(daddr))
1960 goto martian_destination;
1961
1962 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1963 * and call it once if daddr or/and saddr are loopback addresses
1964 */
1965 if (ipv4_is_loopback(daddr)) {
1966 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1967 goto martian_destination;
1968 } else if (ipv4_is_loopback(saddr)) {
1969 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1970 goto martian_source;
1971 }
1972
1973 /*
1974 * Now we are ready to route packet.
1975 */
1976 fl4.flowi4_oif = 0;
1977 fl4.flowi4_iif = dev->ifindex;
1978 fl4.flowi4_mark = skb->mark;
1979 fl4.flowi4_tos = tos;
1980 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1981 fl4.flowi4_flags = 0;
1982 fl4.daddr = daddr;
1983 fl4.saddr = saddr;
1984 fl4.flowi4_uid = sock_net_uid(net, NULL);
1985
1986 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
1987 flkeys = &_flkeys;
1988 } else {
1989 fl4.flowi4_proto = 0;
1990 fl4.fl4_sport = 0;
1991 fl4.fl4_dport = 0;
1992 }
1993
1994 err = fib_lookup(net, &fl4, res, 0);
1995 if (err != 0) {
1996 if (!IN_DEV_FORWARD(in_dev))
1997 err = -EHOSTUNREACH;
1998 goto no_route;
1999 }
2000
2001 if (res->type == RTN_BROADCAST) {
2002 if (IN_DEV_BFORWARD(in_dev))
2003 goto make_route;
2004 goto brd_input;
2005 }
2006
2007 if (res->type == RTN_LOCAL) {
2008 err = fib_validate_source(skb, saddr, daddr, tos,
2009 0, dev, in_dev, &itag);
2010 if (err < 0)
2011 goto martian_source;
2012 goto local_input;
2013 }
2014
2015 if (!IN_DEV_FORWARD(in_dev)) {
2016 err = -EHOSTUNREACH;
2017 goto no_route;
2018 }
2019 if (res->type != RTN_UNICAST)
2020 goto martian_destination;
2021
2022make_route:
2023 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2024out: return err;
2025
2026brd_input:
2027 if (skb->protocol != htons(ETH_P_IP))
2028 goto e_inval;
2029
2030 if (!ipv4_is_zeronet(saddr)) {
2031 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2032 in_dev, &itag);
2033 if (err < 0)
2034 goto martian_source;
2035 }
2036 flags |= RTCF_BROADCAST;
2037 res->type = RTN_BROADCAST;
2038 RT_CACHE_STAT_INC(in_brd);
2039
2040local_input:
2041 do_cache = false;
2042 if (res->fi) {
2043 if (!itag) {
2044 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
2045 if (rt_cache_valid(rth)) {
2046 skb_dst_set_noref(skb, &rth->dst);
2047 err = 0;
2048 goto out;
2049 }
2050 do_cache = true;
2051 }
2052 }
2053
2054 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2055 flags | RTCF_LOCAL, res->type,
2056 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2057 if (!rth)
2058 goto e_nobufs;
2059
2060 rth->dst.output= ip_rt_bug;
2061#ifdef CONFIG_IP_ROUTE_CLASSID
2062 rth->dst.tclassid = itag;
2063#endif
2064 rth->rt_is_input = 1;
2065
2066 RT_CACHE_STAT_INC(in_slow_tot);
2067 if (res->type == RTN_UNREACHABLE) {
2068 rth->dst.input= ip_error;
2069 rth->dst.error= -err;
2070 rth->rt_flags &= ~RTCF_LOCAL;
2071 }
2072
2073 if (do_cache) {
2074 struct fib_nh *nh = &FIB_RES_NH(*res);
2075
2076 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2077 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2078 WARN_ON(rth->dst.input == lwtunnel_input);
2079 rth->dst.lwtstate->orig_input = rth->dst.input;
2080 rth->dst.input = lwtunnel_input;
2081 }
2082
2083 if (unlikely(!rt_cache_route(nh, rth)))
2084 rt_add_uncached_list(rth);
2085 }
2086 skb_dst_set(skb, &rth->dst);
2087 err = 0;
2088 goto out;
2089
2090no_route:
2091 RT_CACHE_STAT_INC(in_no_route);
2092 res->type = RTN_UNREACHABLE;
2093 res->fi = NULL;
2094 res->table = NULL;
2095 goto local_input;
2096
2097 /*
2098 * Do not cache martian addresses: they should be logged (RFC1812)
2099 */
2100martian_destination:
2101 RT_CACHE_STAT_INC(in_martian_dst);
2102#ifdef CONFIG_IP_ROUTE_VERBOSE
2103 if (IN_DEV_LOG_MARTIANS(in_dev))
2104 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2105 &daddr, &saddr, dev->name);
2106#endif
2107
2108e_inval:
2109 err = -EINVAL;
2110 goto out;
2111
2112e_nobufs:
2113 err = -ENOBUFS;
2114 goto out;
2115
2116martian_source:
2117 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2118 goto out;
2119}
2120
2121int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2122 u8 tos, struct net_device *dev)
2123{
2124 struct fib_result res;
2125 int err;
2126
2127 tos &= IPTOS_RT_MASK;
2128 rcu_read_lock();
2129 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2130 rcu_read_unlock();
2131
2132 return err;
2133}
2134EXPORT_SYMBOL(ip_route_input_noref);
2135
2136/* called with rcu_read_lock held */
2137int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2138 u8 tos, struct net_device *dev, struct fib_result *res)
2139{
2140 /* Multicast recognition logic is moved from route cache to here.
2141 The problem was that too many Ethernet cards have broken/missing
2142 hardware multicast filters :-( As result the host on multicasting
2143 network acquires a lot of useless route cache entries, sort of
2144 SDR messages from all the world. Now we try to get rid of them.
2145 Really, provided software IP multicast filter is organized
2146 reasonably (at least, hashed), it does not result in a slowdown
2147 comparing with route cache reject entries.
2148 Note, that multicast routers are not affected, because
2149 route cache entry is created eventually.
2150 */
2151 if (ipv4_is_multicast(daddr)) {
2152 struct in_device *in_dev = __in_dev_get_rcu(dev);
2153 int our = 0;
2154 int err = -EINVAL;
2155
2156 if (!in_dev)
2157 return err;
2158 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2159 ip_hdr(skb)->protocol);
2160
2161 /* check l3 master if no match yet */
2162 if (!our && netif_is_l3_slave(dev)) {
2163 struct in_device *l3_in_dev;
2164
2165 l3_in_dev = __in_dev_get_rcu(skb->dev);
2166 if (l3_in_dev)
2167 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2168 ip_hdr(skb)->protocol);
2169 }
2170
2171 if (our
2172#ifdef CONFIG_IP_MROUTE
2173 ||
2174 (!ipv4_is_local_multicast(daddr) &&
2175 IN_DEV_MFORWARD(in_dev))
2176#endif
2177 ) {
2178 err = ip_route_input_mc(skb, daddr, saddr,
2179 tos, dev, our);
2180 }
2181 return err;
2182 }
2183
2184 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2185}
2186
2187/* called with rcu_read_lock() */
2188static struct rtable *__mkroute_output(const struct fib_result *res,
2189 const struct flowi4 *fl4, int orig_oif,
2190 struct net_device *dev_out,
2191 unsigned int flags)
2192{
2193 struct fib_info *fi = res->fi;
2194 struct fib_nh_exception *fnhe;
2195 struct in_device *in_dev;
2196 u16 type = res->type;
2197 struct rtable *rth;
2198 bool do_cache;
2199
2200 in_dev = __in_dev_get_rcu(dev_out);
2201 if (!in_dev)
2202 return ERR_PTR(-EINVAL);
2203
2204 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2205 if (ipv4_is_loopback(fl4->saddr) &&
2206 !(dev_out->flags & IFF_LOOPBACK) &&
2207 !netif_is_l3_master(dev_out))
2208 return ERR_PTR(-EINVAL);
2209
2210 if (ipv4_is_lbcast(fl4->daddr))
2211 type = RTN_BROADCAST;
2212 else if (ipv4_is_multicast(fl4->daddr))
2213 type = RTN_MULTICAST;
2214 else if (ipv4_is_zeronet(fl4->daddr))
2215 return ERR_PTR(-EINVAL);
2216
2217 if (dev_out->flags & IFF_LOOPBACK)
2218 flags |= RTCF_LOCAL;
2219
2220 do_cache = true;
2221 if (type == RTN_BROADCAST) {
2222 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2223 fi = NULL;
2224 } else if (type == RTN_MULTICAST) {
2225 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2226 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2227 fl4->flowi4_proto))
2228 flags &= ~RTCF_LOCAL;
2229 else
2230 do_cache = false;
2231 /* If multicast route do not exist use
2232 * default one, but do not gateway in this case.
2233 * Yes, it is hack.
2234 */
2235 if (fi && res->prefixlen < 4)
2236 fi = NULL;
2237 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2238 (orig_oif != dev_out->ifindex)) {
2239 /* For local routes that require a particular output interface
2240 * we do not want to cache the result. Caching the result
2241 * causes incorrect behaviour when there are multiple source
2242 * addresses on the interface, the end result being that if the
2243 * intended recipient is waiting on that interface for the
2244 * packet he won't receive it because it will be delivered on
2245 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2246 * be set to the loopback interface as well.
2247 */
2248 do_cache = false;
2249 }
2250
2251 fnhe = NULL;
2252 do_cache &= fi != NULL;
2253 if (fi) {
2254 struct rtable __rcu **prth;
2255 struct fib_nh *nh = &FIB_RES_NH(*res);
2256
2257 fnhe = find_exception(nh, fl4->daddr);
2258 if (!do_cache)
2259 goto add;
2260 if (fnhe) {
2261 prth = &fnhe->fnhe_rth_output;
2262 } else {
2263 if (unlikely(fl4->flowi4_flags &
2264 FLOWI_FLAG_KNOWN_NH &&
2265 !(nh->nh_gw &&
2266 nh->nh_scope == RT_SCOPE_LINK))) {
2267 do_cache = false;
2268 goto add;
2269 }
2270 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2271 }
2272 rth = rcu_dereference(*prth);
2273 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2274 return rth;
2275 }
2276
2277add:
2278 rth = rt_dst_alloc(dev_out, flags, type,
2279 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2280 IN_DEV_CONF_GET(in_dev, NOXFRM),
2281 do_cache);
2282 if (!rth)
2283 return ERR_PTR(-ENOBUFS);
2284
2285 rth->rt_iif = orig_oif;
2286
2287 RT_CACHE_STAT_INC(out_slow_tot);
2288
2289 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2290 if (flags & RTCF_LOCAL &&
2291 !(dev_out->flags & IFF_LOOPBACK)) {
2292 rth->dst.output = ip_mc_output;
2293 RT_CACHE_STAT_INC(out_slow_mc);
2294 }
2295#ifdef CONFIG_IP_MROUTE
2296 if (type == RTN_MULTICAST) {
2297 if (IN_DEV_MFORWARD(in_dev) &&
2298 !ipv4_is_local_multicast(fl4->daddr)) {
2299 rth->dst.input = ip_mr_input;
2300 rth->dst.output = ip_mc_output;
2301 }
2302 }
2303#endif
2304 }
2305
2306 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2307 lwtunnel_set_redirect(&rth->dst);
2308
2309 return rth;
2310}
2311
2312/*
2313 * Major route resolver routine.
2314 */
2315
2316struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2317 const struct sk_buff *skb)
2318{
2319 __u8 tos = RT_FL_TOS(fl4);
2320 struct fib_result res = {
2321 .type = RTN_UNSPEC,
2322 .fi = NULL,
2323 .table = NULL,
2324 .tclassid = 0,
2325 };
2326 struct rtable *rth;
2327
2328 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2329 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2330 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2331 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2332
2333 rcu_read_lock();
2334 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2335 rcu_read_unlock();
2336
2337 return rth;
2338}
2339EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2340
2341struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2342 struct fib_result *res,
2343 const struct sk_buff *skb)
2344{
2345 struct net_device *dev_out = NULL;
2346 int orig_oif = fl4->flowi4_oif;
2347 unsigned int flags = 0;
2348 struct rtable *rth;
2349 int err = -ENETUNREACH;
2350
2351 if (fl4->saddr) {
2352 rth = ERR_PTR(-EINVAL);
2353 if (ipv4_is_multicast(fl4->saddr) ||
2354 ipv4_is_lbcast(fl4->saddr) ||
2355 ipv4_is_zeronet(fl4->saddr))
2356 goto out;
2357
2358 /* I removed check for oif == dev_out->oif here.
2359 It was wrong for two reasons:
2360 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2361 is assigned to multiple interfaces.
2362 2. Moreover, we are allowed to send packets with saddr
2363 of another iface. --ANK
2364 */
2365
2366 if (fl4->flowi4_oif == 0 &&
2367 (ipv4_is_multicast(fl4->daddr) ||
2368 ipv4_is_lbcast(fl4->daddr))) {
2369 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2370 dev_out = __ip_dev_find(net, fl4->saddr, false);
2371 if (!dev_out)
2372 goto out;
2373
2374 /* Special hack: user can direct multicasts
2375 and limited broadcast via necessary interface
2376 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2377 This hack is not just for fun, it allows
2378 vic,vat and friends to work.
2379 They bind socket to loopback, set ttl to zero
2380 and expect that it will work.
2381 From the viewpoint of routing cache they are broken,
2382 because we are not allowed to build multicast path
2383 with loopback source addr (look, routing cache
2384 cannot know, that ttl is zero, so that packet
2385 will not leave this host and route is valid).
2386 Luckily, this hack is good workaround.
2387 */
2388
2389 fl4->flowi4_oif = dev_out->ifindex;
2390 goto make_route;
2391 }
2392
2393 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2394 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2395 if (!__ip_dev_find(net, fl4->saddr, false))
2396 goto out;
2397 }
2398 }
2399
2400
2401 if (fl4->flowi4_oif) {
2402 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2403 rth = ERR_PTR(-ENODEV);
2404 if (!dev_out)
2405 goto out;
2406
2407 /* RACE: Check return value of inet_select_addr instead. */
2408 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2409 rth = ERR_PTR(-ENETUNREACH);
2410 goto out;
2411 }
2412 if (ipv4_is_local_multicast(fl4->daddr) ||
2413 ipv4_is_lbcast(fl4->daddr) ||
2414 fl4->flowi4_proto == IPPROTO_IGMP) {
2415 if (!fl4->saddr)
2416 fl4->saddr = inet_select_addr(dev_out, 0,
2417 RT_SCOPE_LINK);
2418 goto make_route;
2419 }
2420 if (!fl4->saddr) {
2421 if (ipv4_is_multicast(fl4->daddr))
2422 fl4->saddr = inet_select_addr(dev_out, 0,
2423 fl4->flowi4_scope);
2424 else if (!fl4->daddr)
2425 fl4->saddr = inet_select_addr(dev_out, 0,
2426 RT_SCOPE_HOST);
2427 }
2428 }
2429
2430 if (!fl4->daddr) {
2431 fl4->daddr = fl4->saddr;
2432 if (!fl4->daddr)
2433 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2434 dev_out = net->loopback_dev;
2435 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2436 res->type = RTN_LOCAL;
2437 flags |= RTCF_LOCAL;
2438 goto make_route;
2439 }
2440
2441 err = fib_lookup(net, fl4, res, 0);
2442 if (err) {
2443 res->fi = NULL;
2444 res->table = NULL;
2445 if (fl4->flowi4_oif &&
2446 (ipv4_is_multicast(fl4->daddr) ||
2447 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2448 /* Apparently, routing tables are wrong. Assume,
2449 that the destination is on link.
2450
2451 WHY? DW.
2452 Because we are allowed to send to iface
2453 even if it has NO routes and NO assigned
2454 addresses. When oif is specified, routing
2455 tables are looked up with only one purpose:
2456 to catch if destination is gatewayed, rather than
2457 direct. Moreover, if MSG_DONTROUTE is set,
2458 we send packet, ignoring both routing tables
2459 and ifaddr state. --ANK
2460
2461
2462 We could make it even if oif is unknown,
2463 likely IPv6, but we do not.
2464 */
2465
2466 if (fl4->saddr == 0)
2467 fl4->saddr = inet_select_addr(dev_out, 0,
2468 RT_SCOPE_LINK);
2469 res->type = RTN_UNICAST;
2470 goto make_route;
2471 }
2472 rth = ERR_PTR(err);
2473 goto out;
2474 }
2475
2476 if (res->type == RTN_LOCAL) {
2477 if (!fl4->saddr) {
2478 if (res->fi->fib_prefsrc)
2479 fl4->saddr = res->fi->fib_prefsrc;
2480 else
2481 fl4->saddr = fl4->daddr;
2482 }
2483
2484 /* L3 master device is the loopback for that domain */
2485 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2486 net->loopback_dev;
2487
2488 /* make sure orig_oif points to fib result device even
2489 * though packet rx/tx happens over loopback or l3mdev
2490 */
2491 orig_oif = FIB_RES_OIF(*res);
2492
2493 fl4->flowi4_oif = dev_out->ifindex;
2494 flags |= RTCF_LOCAL;
2495 goto make_route;
2496 }
2497
2498 fib_select_path(net, res, fl4, skb);
2499
2500 dev_out = FIB_RES_DEV(*res);
2501 fl4->flowi4_oif = dev_out->ifindex;
2502
2503
2504make_route:
2505 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2506
2507out:
2508 return rth;
2509}
2510
2511static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2512{
2513 return NULL;
2514}
2515
2516static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2517{
2518 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2519
2520 return mtu ? : dst->dev->mtu;
2521}
2522
2523static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2524 struct sk_buff *skb, u32 mtu)
2525{
2526}
2527
2528static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2529 struct sk_buff *skb)
2530{
2531}
2532
2533static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2534 unsigned long old)
2535{
2536 return NULL;
2537}
2538
2539static struct dst_ops ipv4_dst_blackhole_ops = {
2540 .family = AF_INET,
2541 .check = ipv4_blackhole_dst_check,
2542 .mtu = ipv4_blackhole_mtu,
2543 .default_advmss = ipv4_default_advmss,
2544 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2545 .redirect = ipv4_rt_blackhole_redirect,
2546 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2547 .neigh_lookup = ipv4_neigh_lookup,
2548};
2549
2550struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2551{
2552 struct rtable *ort = (struct rtable *) dst_orig;
2553 struct rtable *rt;
2554
2555 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2556 if (rt) {
2557 struct dst_entry *new = &rt->dst;
2558
2559 new->__use = 1;
2560 new->input = dst_discard;
2561 new->output = dst_discard_out;
2562
2563 new->dev = net->loopback_dev;
2564 if (new->dev)
2565 dev_hold(new->dev);
2566
2567 rt->rt_is_input = ort->rt_is_input;
2568 rt->rt_iif = ort->rt_iif;
2569 rt->rt_pmtu = ort->rt_pmtu;
2570 rt->rt_mtu_locked = ort->rt_mtu_locked;
2571
2572 rt->rt_genid = rt_genid_ipv4(net);
2573 rt->rt_flags = ort->rt_flags;
2574 rt->rt_type = ort->rt_type;
2575 rt->rt_gateway = ort->rt_gateway;
2576 rt->rt_uses_gateway = ort->rt_uses_gateway;
2577
2578 INIT_LIST_HEAD(&rt->rt_uncached);
2579 }
2580
2581 dst_release(dst_orig);
2582
2583 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2584}
2585
2586struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2587 const struct sock *sk)
2588{
2589 struct rtable *rt = __ip_route_output_key(net, flp4);
2590
2591 if (IS_ERR(rt))
2592 return rt;
2593
2594 if (flp4->flowi4_proto)
2595 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2596 flowi4_to_flowi(flp4),
2597 sk, 0);
2598
2599 return rt;
2600}
2601EXPORT_SYMBOL_GPL(ip_route_output_flow);
2602
2603/* called with rcu_read_lock held */
2604static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2605 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2606 struct sk_buff *skb, u32 portid, u32 seq)
2607{
2608 struct rtmsg *r;
2609 struct nlmsghdr *nlh;
2610 unsigned long expires = 0;
2611 u32 error;
2612 u32 metrics[RTAX_MAX];
2613
2614 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2615 if (!nlh)
2616 return -EMSGSIZE;
2617
2618 r = nlmsg_data(nlh);
2619 r->rtm_family = AF_INET;
2620 r->rtm_dst_len = 32;
2621 r->rtm_src_len = 0;
2622 r->rtm_tos = fl4->flowi4_tos;
2623 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2624 if (nla_put_u32(skb, RTA_TABLE, table_id))
2625 goto nla_put_failure;
2626 r->rtm_type = rt->rt_type;
2627 r->rtm_scope = RT_SCOPE_UNIVERSE;
2628 r->rtm_protocol = RTPROT_UNSPEC;
2629 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2630 if (rt->rt_flags & RTCF_NOTIFY)
2631 r->rtm_flags |= RTM_F_NOTIFY;
2632 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2633 r->rtm_flags |= RTCF_DOREDIRECT;
2634
2635 if (nla_put_in_addr(skb, RTA_DST, dst))
2636 goto nla_put_failure;
2637 if (src) {
2638 r->rtm_src_len = 32;
2639 if (nla_put_in_addr(skb, RTA_SRC, src))
2640 goto nla_put_failure;
2641 }
2642 if (rt->dst.dev &&
2643 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2644 goto nla_put_failure;
2645#ifdef CONFIG_IP_ROUTE_CLASSID
2646 if (rt->dst.tclassid &&
2647 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2648 goto nla_put_failure;
2649#endif
2650 if (!rt_is_input_route(rt) &&
2651 fl4->saddr != src) {
2652 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2653 goto nla_put_failure;
2654 }
2655 if (rt->rt_uses_gateway &&
2656 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2657 goto nla_put_failure;
2658
2659 expires = rt->dst.expires;
2660 if (expires) {
2661 unsigned long now = jiffies;
2662
2663 if (time_before(now, expires))
2664 expires -= now;
2665 else
2666 expires = 0;
2667 }
2668
2669 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2670 if (rt->rt_pmtu && expires)
2671 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2672 if (rt->rt_mtu_locked && expires)
2673 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2674 if (rtnetlink_put_metrics(skb, metrics) < 0)
2675 goto nla_put_failure;
2676
2677 if (fl4->flowi4_mark &&
2678 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2679 goto nla_put_failure;
2680
2681 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2682 nla_put_u32(skb, RTA_UID,
2683 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2684 goto nla_put_failure;
2685
2686 error = rt->dst.error;
2687
2688 if (rt_is_input_route(rt)) {
2689#ifdef CONFIG_IP_MROUTE
2690 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2691 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2692 int err = ipmr_get_route(net, skb,
2693 fl4->saddr, fl4->daddr,
2694 r, portid);
2695
2696 if (err <= 0) {
2697 if (err == 0)
2698 return 0;
2699 goto nla_put_failure;
2700 }
2701 } else
2702#endif
2703 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
2704 goto nla_put_failure;
2705 }
2706
2707 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2708 goto nla_put_failure;
2709
2710 nlmsg_end(skb, nlh);
2711 return 0;
2712
2713nla_put_failure:
2714 nlmsg_cancel(skb, nlh);
2715 return -EMSGSIZE;
2716}
2717
2718static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
2719 u8 ip_proto, __be16 sport,
2720 __be16 dport)
2721{
2722 struct sk_buff *skb;
2723 struct iphdr *iph;
2724
2725 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2726 if (!skb)
2727 return NULL;
2728
2729 /* Reserve room for dummy headers, this skb can pass
2730 * through good chunk of routing engine.
2731 */
2732 skb_reset_mac_header(skb);
2733 skb_reset_network_header(skb);
2734 skb->protocol = htons(ETH_P_IP);
2735 iph = skb_put(skb, sizeof(struct iphdr));
2736 iph->protocol = ip_proto;
2737 iph->saddr = src;
2738 iph->daddr = dst;
2739 iph->version = 0x4;
2740 iph->frag_off = 0;
2741 iph->ihl = 0x5;
2742 skb_set_transport_header(skb, skb->len);
2743
2744 switch (iph->protocol) {
2745 case IPPROTO_UDP: {
2746 struct udphdr *udph;
2747
2748 udph = skb_put_zero(skb, sizeof(struct udphdr));
2749 udph->source = sport;
2750 udph->dest = dport;
2751 udph->len = sizeof(struct udphdr);
2752 udph->check = 0;
2753 break;
2754 }
2755 case IPPROTO_TCP: {
2756 struct tcphdr *tcph;
2757
2758 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
2759 tcph->source = sport;
2760 tcph->dest = dport;
2761 tcph->doff = sizeof(struct tcphdr) / 4;
2762 tcph->rst = 1;
2763 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
2764 src, dst, 0);
2765 break;
2766 }
2767 case IPPROTO_ICMP: {
2768 struct icmphdr *icmph;
2769
2770 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
2771 icmph->type = ICMP_ECHO;
2772 icmph->code = 0;
2773 }
2774 }
2775
2776 return skb;
2777}
2778
2779static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
2780 const struct nlmsghdr *nlh,
2781 struct nlattr **tb,
2782 struct netlink_ext_ack *extack)
2783{
2784 struct rtmsg *rtm;
2785 int i, err;
2786
2787 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
2788 NL_SET_ERR_MSG(extack,
2789 "ipv4: Invalid header for route get request");
2790 return -EINVAL;
2791 }
2792
2793 if (!netlink_strict_get_check(skb))
2794 return nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX,
2795 rtm_ipv4_policy, extack);
2796
2797 rtm = nlmsg_data(nlh);
2798 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
2799 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
2800 rtm->rtm_table || rtm->rtm_protocol ||
2801 rtm->rtm_scope || rtm->rtm_type) {
2802 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
2803 return -EINVAL;
2804 }
2805
2806 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
2807 RTM_F_LOOKUP_TABLE |
2808 RTM_F_FIB_MATCH)) {
2809 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
2810 return -EINVAL;
2811 }
2812
2813 err = nlmsg_parse_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
2814 rtm_ipv4_policy, extack);
2815 if (err)
2816 return err;
2817
2818 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
2819 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
2820 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
2821 return -EINVAL;
2822 }
2823
2824 for (i = 0; i <= RTA_MAX; i++) {
2825 if (!tb[i])
2826 continue;
2827
2828 switch (i) {
2829 case RTA_IIF:
2830 case RTA_OIF:
2831 case