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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
364static int rt_acct_proc_open(struct inode *inode, struct file *file)
365{
366 return single_open(file, rt_acct_proc_show, NULL);
367}
368
369static const struct file_operations rt_acct_proc_fops = {
370 .open = rt_acct_proc_open,
371 .read = seq_read,
372 .llseek = seq_lseek,
373 .release = single_release,
374};
375#endif
376
377static int __net_init ip_rt_do_proc_init(struct net *net)
378{
379 struct proc_dir_entry *pde;
380
381 pde = proc_create("rt_cache", 0444, net->proc_net,
382 &rt_cache_seq_fops);
383 if (!pde)
384 goto err1;
385
386 pde = proc_create("rt_cache", 0444,
387 net->proc_net_stat, &rt_cpu_seq_fops);
388 if (!pde)
389 goto err2;
390
391#ifdef CONFIG_IP_ROUTE_CLASSID
392 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops);
393 if (!pde)
394 goto err3;
395#endif
396 return 0;
397
398#ifdef CONFIG_IP_ROUTE_CLASSID
399err3:
400 remove_proc_entry("rt_cache", net->proc_net_stat);
401#endif
402err2:
403 remove_proc_entry("rt_cache", net->proc_net);
404err1:
405 return -ENOMEM;
406}
407
408static void __net_exit ip_rt_do_proc_exit(struct net *net)
409{
410 remove_proc_entry("rt_cache", net->proc_net_stat);
411 remove_proc_entry("rt_cache", net->proc_net);
412#ifdef CONFIG_IP_ROUTE_CLASSID
413 remove_proc_entry("rt_acct", net->proc_net);
414#endif
415}
416
417static struct pernet_operations ip_rt_proc_ops __net_initdata = {
418 .init = ip_rt_do_proc_init,
419 .exit = ip_rt_do_proc_exit,
420};
421
422static int __init ip_rt_proc_init(void)
423{
424 return register_pernet_subsys(&ip_rt_proc_ops);
425}
426
427#else
428static inline int ip_rt_proc_init(void)
429{
430 return 0;
431}
432#endif /* CONFIG_PROC_FS */
433
434static inline bool rt_is_expired(const struct rtable *rth)
435{
436 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
437}
438
439void rt_cache_flush(struct net *net)
440{
441 rt_genid_bump_ipv4(net);
442}
443
444static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
445 struct sk_buff *skb,
446 const void *daddr)
447{
448 struct net_device *dev = dst->dev;
449 const __be32 *pkey = daddr;
450 const struct rtable *rt;
451 struct neighbour *n;
452
453 rt = (const struct rtable *) dst;
454 if (rt->rt_gateway)
455 pkey = (const __be32 *) &rt->rt_gateway;
456 else if (skb)
457 pkey = &ip_hdr(skb)->daddr;
458
459 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
460 if (n)
461 return n;
462 return neigh_create(&arp_tbl, pkey, dev);
463}
464
465static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
466{
467 struct net_device *dev = dst->dev;
468 const __be32 *pkey = daddr;
469 const struct rtable *rt;
470
471 rt = (const struct rtable *)dst;
472 if (rt->rt_gateway)
473 pkey = (const __be32 *)&rt->rt_gateway;
474 else if (!daddr ||
475 (rt->rt_flags &
476 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
477 return;
478
479 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
480}
481
482#define IP_IDENTS_SZ 2048u
483
484static atomic_t *ip_idents __read_mostly;
485static u32 *ip_tstamps __read_mostly;
486
487/* In order to protect privacy, we add a perturbation to identifiers
488 * if one generator is seldom used. This makes hard for an attacker
489 * to infer how many packets were sent between two points in time.
490 */
491u32 ip_idents_reserve(u32 hash, int segs)
492{
493 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
494 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
495 u32 old = READ_ONCE(*p_tstamp);
496 u32 now = (u32)jiffies;
497 u32 new, delta = 0;
498
499 if (old != now && cmpxchg(p_tstamp, old, now) == old)
500 delta = prandom_u32_max(now - old);
501
502 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
503 do {
504 old = (u32)atomic_read(p_id);
505 new = old + delta + segs;
506 } while (atomic_cmpxchg(p_id, old, new) != old);
507
508 return new - segs;
509}
510EXPORT_SYMBOL(ip_idents_reserve);
511
512void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
513{
514 static u32 ip_idents_hashrnd __read_mostly;
515 u32 hash, id;
516
517 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd));
518
519 hash = jhash_3words((__force u32)iph->daddr,
520 (__force u32)iph->saddr,
521 iph->protocol ^ net_hash_mix(net),
522 ip_idents_hashrnd);
523 id = ip_idents_reserve(hash, segs);
524 iph->id = htons(id);
525}
526EXPORT_SYMBOL(__ip_select_ident);
527
528static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
529 const struct sock *sk,
530 const struct iphdr *iph,
531 int oif, u8 tos,
532 u8 prot, u32 mark, int flow_flags)
533{
534 if (sk) {
535 const struct inet_sock *inet = inet_sk(sk);
536
537 oif = sk->sk_bound_dev_if;
538 mark = sk->sk_mark;
539 tos = RT_CONN_FLAGS(sk);
540 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
541 }
542 flowi4_init_output(fl4, oif, mark, tos,
543 RT_SCOPE_UNIVERSE, prot,
544 flow_flags,
545 iph->daddr, iph->saddr, 0, 0,
546 sock_net_uid(net, sk));
547}
548
549static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
550 const struct sock *sk)
551{
552 const struct net *net = dev_net(skb->dev);
553 const struct iphdr *iph = ip_hdr(skb);
554 int oif = skb->dev->ifindex;
555 u8 tos = RT_TOS(iph->tos);
556 u8 prot = iph->protocol;
557 u32 mark = skb->mark;
558
559 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
560}
561
562static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
563{
564 const struct inet_sock *inet = inet_sk(sk);
565 const struct ip_options_rcu *inet_opt;
566 __be32 daddr = inet->inet_daddr;
567
568 rcu_read_lock();
569 inet_opt = rcu_dereference(inet->inet_opt);
570 if (inet_opt && inet_opt->opt.srr)
571 daddr = inet_opt->opt.faddr;
572 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
573 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
574 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
575 inet_sk_flowi_flags(sk),
576 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
577 rcu_read_unlock();
578}
579
580static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
581 const struct sk_buff *skb)
582{
583 if (skb)
584 build_skb_flow_key(fl4, skb, sk);
585 else
586 build_sk_flow_key(fl4, sk);
587}
588
589static DEFINE_SPINLOCK(fnhe_lock);
590
591static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
592{
593 struct rtable *rt;
594
595 rt = rcu_dereference(fnhe->fnhe_rth_input);
596 if (rt) {
597 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
598 dst_dev_put(&rt->dst);
599 dst_release(&rt->dst);
600 }
601 rt = rcu_dereference(fnhe->fnhe_rth_output);
602 if (rt) {
603 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
604 dst_dev_put(&rt->dst);
605 dst_release(&rt->dst);
606 }
607}
608
609static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
610{
611 struct fib_nh_exception *fnhe, *oldest;
612
613 oldest = rcu_dereference(hash->chain);
614 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
615 fnhe = rcu_dereference(fnhe->fnhe_next)) {
616 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
617 oldest = fnhe;
618 }
619 fnhe_flush_routes(oldest);
620 return oldest;
621}
622
623static inline u32 fnhe_hashfun(__be32 daddr)
624{
625 static u32 fnhe_hashrnd __read_mostly;
626 u32 hval;
627
628 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
629 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
630 return hash_32(hval, FNHE_HASH_SHIFT);
631}
632
633static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
634{
635 rt->rt_pmtu = fnhe->fnhe_pmtu;
636 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
637 rt->dst.expires = fnhe->fnhe_expires;
638
639 if (fnhe->fnhe_gw) {
640 rt->rt_flags |= RTCF_REDIRECTED;
641 rt->rt_gateway = fnhe->fnhe_gw;
642 rt->rt_uses_gateway = 1;
643 }
644}
645
646static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
647 u32 pmtu, bool lock, unsigned long expires)
648{
649 struct fnhe_hash_bucket *hash;
650 struct fib_nh_exception *fnhe;
651 struct rtable *rt;
652 u32 genid, hval;
653 unsigned int i;
654 int depth;
655
656 genid = fnhe_genid(dev_net(nh->nh_dev));
657 hval = fnhe_hashfun(daddr);
658
659 spin_lock_bh(&fnhe_lock);
660
661 hash = rcu_dereference(nh->nh_exceptions);
662 if (!hash) {
663 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
664 if (!hash)
665 goto out_unlock;
666 rcu_assign_pointer(nh->nh_exceptions, hash);
667 }
668
669 hash += hval;
670
671 depth = 0;
672 for (fnhe = rcu_dereference(hash->chain); fnhe;
673 fnhe = rcu_dereference(fnhe->fnhe_next)) {
674 if (fnhe->fnhe_daddr == daddr)
675 break;
676 depth++;
677 }
678
679 if (fnhe) {
680 if (fnhe->fnhe_genid != genid)
681 fnhe->fnhe_genid = genid;
682 if (gw)
683 fnhe->fnhe_gw = gw;
684 if (pmtu) {
685 fnhe->fnhe_pmtu = pmtu;
686 fnhe->fnhe_mtu_locked = lock;
687 }
688 fnhe->fnhe_expires = max(1UL, expires);
689 /* Update all cached dsts too */
690 rt = rcu_dereference(fnhe->fnhe_rth_input);
691 if (rt)
692 fill_route_from_fnhe(rt, fnhe);
693 rt = rcu_dereference(fnhe->fnhe_rth_output);
694 if (rt)
695 fill_route_from_fnhe(rt, fnhe);
696 } else {
697 if (depth > FNHE_RECLAIM_DEPTH)
698 fnhe = fnhe_oldest(hash);
699 else {
700 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
701 if (!fnhe)
702 goto out_unlock;
703
704 fnhe->fnhe_next = hash->chain;
705 rcu_assign_pointer(hash->chain, fnhe);
706 }
707 fnhe->fnhe_genid = genid;
708 fnhe->fnhe_daddr = daddr;
709 fnhe->fnhe_gw = gw;
710 fnhe->fnhe_pmtu = pmtu;
711 fnhe->fnhe_mtu_locked = lock;
712 fnhe->fnhe_expires = max(1UL, expires);
713
714 /* Exception created; mark the cached routes for the nexthop
715 * stale, so anyone caching it rechecks if this exception
716 * applies to them.
717 */
718 rt = rcu_dereference(nh->nh_rth_input);
719 if (rt)
720 rt->dst.obsolete = DST_OBSOLETE_KILL;
721
722 for_each_possible_cpu(i) {
723 struct rtable __rcu **prt;
724 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i);
725 rt = rcu_dereference(*prt);
726 if (rt)
727 rt->dst.obsolete = DST_OBSOLETE_KILL;
728 }
729 }
730
731 fnhe->fnhe_stamp = jiffies;
732
733out_unlock:
734 spin_unlock_bh(&fnhe_lock);
735}
736
737static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
738 bool kill_route)
739{
740 __be32 new_gw = icmp_hdr(skb)->un.gateway;
741 __be32 old_gw = ip_hdr(skb)->saddr;
742 struct net_device *dev = skb->dev;
743 struct in_device *in_dev;
744 struct fib_result res;
745 struct neighbour *n;
746 struct net *net;
747
748 switch (icmp_hdr(skb)->code & 7) {
749 case ICMP_REDIR_NET:
750 case ICMP_REDIR_NETTOS:
751 case ICMP_REDIR_HOST:
752 case ICMP_REDIR_HOSTTOS:
753 break;
754
755 default:
756 return;
757 }
758
759 if (rt->rt_gateway != old_gw)
760 return;
761
762 in_dev = __in_dev_get_rcu(dev);
763 if (!in_dev)
764 return;
765
766 net = dev_net(dev);
767 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
768 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
769 ipv4_is_zeronet(new_gw))
770 goto reject_redirect;
771
772 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
773 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
774 goto reject_redirect;
775 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
776 goto reject_redirect;
777 } else {
778 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
779 goto reject_redirect;
780 }
781
782 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
783 if (!n)
784 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
785 if (!IS_ERR(n)) {
786 if (!(n->nud_state & NUD_VALID)) {
787 neigh_event_send(n, NULL);
788 } else {
789 if (fib_lookup(net, fl4, &res, 0) == 0) {
790 struct fib_nh *nh = &FIB_RES_NH(res);
791
792 update_or_create_fnhe(nh, fl4->daddr, new_gw,
793 0, false,
794 jiffies + ip_rt_gc_timeout);
795 }
796 if (kill_route)
797 rt->dst.obsolete = DST_OBSOLETE_KILL;
798 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
799 }
800 neigh_release(n);
801 }
802 return;
803
804reject_redirect:
805#ifdef CONFIG_IP_ROUTE_VERBOSE
806 if (IN_DEV_LOG_MARTIANS(in_dev)) {
807 const struct iphdr *iph = (const struct iphdr *) skb->data;
808 __be32 daddr = iph->daddr;
809 __be32 saddr = iph->saddr;
810
811 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
812 " Advised path = %pI4 -> %pI4\n",
813 &old_gw, dev->name, &new_gw,
814 &saddr, &daddr);
815 }
816#endif
817 ;
818}
819
820static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
821{
822 struct rtable *rt;
823 struct flowi4 fl4;
824 const struct iphdr *iph = (const struct iphdr *) skb->data;
825 struct net *net = dev_net(skb->dev);
826 int oif = skb->dev->ifindex;
827 u8 tos = RT_TOS(iph->tos);
828 u8 prot = iph->protocol;
829 u32 mark = skb->mark;
830
831 rt = (struct rtable *) dst;
832
833 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
834 __ip_do_redirect(rt, skb, &fl4, true);
835}
836
837static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
838{
839 struct rtable *rt = (struct rtable *)dst;
840 struct dst_entry *ret = dst;
841
842 if (rt) {
843 if (dst->obsolete > 0) {
844 ip_rt_put(rt);
845 ret = NULL;
846 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
847 rt->dst.expires) {
848 ip_rt_put(rt);
849 ret = NULL;
850 }
851 }
852 return ret;
853}
854
855/*
856 * Algorithm:
857 * 1. The first ip_rt_redirect_number redirects are sent
858 * with exponential backoff, then we stop sending them at all,
859 * assuming that the host ignores our redirects.
860 * 2. If we did not see packets requiring redirects
861 * during ip_rt_redirect_silence, we assume that the host
862 * forgot redirected route and start to send redirects again.
863 *
864 * This algorithm is much cheaper and more intelligent than dumb load limiting
865 * in icmp.c.
866 *
867 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
868 * and "frag. need" (breaks PMTU discovery) in icmp.c.
869 */
870
871void ip_rt_send_redirect(struct sk_buff *skb)
872{
873 struct rtable *rt = skb_rtable(skb);
874 struct in_device *in_dev;
875 struct inet_peer *peer;
876 struct net *net;
877 int log_martians;
878 int vif;
879
880 rcu_read_lock();
881 in_dev = __in_dev_get_rcu(rt->dst.dev);
882 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
883 rcu_read_unlock();
884 return;
885 }
886 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
887 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
888 rcu_read_unlock();
889
890 net = dev_net(rt->dst.dev);
891 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
892 if (!peer) {
893 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
894 rt_nexthop(rt, ip_hdr(skb)->daddr));
895 return;
896 }
897
898 /* No redirected packets during ip_rt_redirect_silence;
899 * reset the algorithm.
900 */
901 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
902 peer->rate_tokens = 0;
903
904 /* Too many ignored redirects; do not send anything
905 * set dst.rate_last to the last seen redirected packet.
906 */
907 if (peer->rate_tokens >= ip_rt_redirect_number) {
908 peer->rate_last = jiffies;
909 goto out_put_peer;
910 }
911
912 /* Check for load limit; set rate_last to the latest sent
913 * redirect.
914 */
915 if (peer->rate_tokens == 0 ||
916 time_after(jiffies,
917 (peer->rate_last +
918 (ip_rt_redirect_load << peer->rate_tokens)))) {
919 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
920
921 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
922 peer->rate_last = jiffies;
923 ++peer->rate_tokens;
924#ifdef CONFIG_IP_ROUTE_VERBOSE
925 if (log_martians &&
926 peer->rate_tokens == ip_rt_redirect_number)
927 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
928 &ip_hdr(skb)->saddr, inet_iif(skb),
929 &ip_hdr(skb)->daddr, &gw);
930#endif
931 }
932out_put_peer:
933 inet_putpeer(peer);
934}
935
936static int ip_error(struct sk_buff *skb)
937{
938 struct rtable *rt = skb_rtable(skb);
939 struct net_device *dev = skb->dev;
940 struct in_device *in_dev;
941 struct inet_peer *peer;
942 unsigned long now;
943 struct net *net;
944 bool send;
945 int code;
946
947 if (netif_is_l3_master(skb->dev)) {
948 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
949 if (!dev)
950 goto out;
951 }
952
953 in_dev = __in_dev_get_rcu(dev);
954
955 /* IP on this device is disabled. */
956 if (!in_dev)
957 goto out;
958
959 net = dev_net(rt->dst.dev);
960 if (!IN_DEV_FORWARD(in_dev)) {
961 switch (rt->dst.error) {
962 case EHOSTUNREACH:
963 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
964 break;
965
966 case ENETUNREACH:
967 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
968 break;
969 }
970 goto out;
971 }
972
973 switch (rt->dst.error) {
974 case EINVAL:
975 default:
976 goto out;
977 case EHOSTUNREACH:
978 code = ICMP_HOST_UNREACH;
979 break;
980 case ENETUNREACH:
981 code = ICMP_NET_UNREACH;
982 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
983 break;
984 case EACCES:
985 code = ICMP_PKT_FILTERED;
986 break;
987 }
988
989 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
990 l3mdev_master_ifindex(skb->dev), 1);
991
992 send = true;
993 if (peer) {
994 now = jiffies;
995 peer->rate_tokens += now - peer->rate_last;
996 if (peer->rate_tokens > ip_rt_error_burst)
997 peer->rate_tokens = ip_rt_error_burst;
998 peer->rate_last = now;
999 if (peer->rate_tokens >= ip_rt_error_cost)
1000 peer->rate_tokens -= ip_rt_error_cost;
1001 else
1002 send = false;
1003 inet_putpeer(peer);
1004 }
1005 if (send)
1006 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1007
1008out: kfree_skb(skb);
1009 return 0;
1010}
1011
1012static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1013{
1014 struct dst_entry *dst = &rt->dst;
1015 struct fib_result res;
1016 bool lock = false;
1017
1018 if (ip_mtu_locked(dst))
1019 return;
1020
1021 if (ipv4_mtu(dst) < mtu)
1022 return;
1023
1024 if (mtu < ip_rt_min_pmtu) {
1025 lock = true;
1026 mtu = ip_rt_min_pmtu;
1027 }
1028
1029 if (rt->rt_pmtu == mtu &&
1030 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1031 return;
1032
1033 rcu_read_lock();
1034 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1035 struct fib_nh *nh = &FIB_RES_NH(res);
1036
1037 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, lock,
1038 jiffies + ip_rt_mtu_expires);
1039 }
1040 rcu_read_unlock();
1041}
1042
1043static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1044 struct sk_buff *skb, u32 mtu)
1045{
1046 struct rtable *rt = (struct rtable *) dst;
1047 struct flowi4 fl4;
1048
1049 ip_rt_build_flow_key(&fl4, sk, skb);
1050 __ip_rt_update_pmtu(rt, &fl4, mtu);
1051}
1052
1053void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1054 int oif, u32 mark, u8 protocol, int flow_flags)
1055{
1056 const struct iphdr *iph = (const struct iphdr *) skb->data;
1057 struct flowi4 fl4;
1058 struct rtable *rt;
1059
1060 if (!mark)
1061 mark = IP4_REPLY_MARK(net, skb->mark);
1062
1063 __build_flow_key(net, &fl4, NULL, iph, oif,
1064 RT_TOS(iph->tos), protocol, mark, flow_flags);
1065 rt = __ip_route_output_key(net, &fl4);
1066 if (!IS_ERR(rt)) {
1067 __ip_rt_update_pmtu(rt, &fl4, mtu);
1068 ip_rt_put(rt);
1069 }
1070}
1071EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1072
1073static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1074{
1075 const struct iphdr *iph = (const struct iphdr *) skb->data;
1076 struct flowi4 fl4;
1077 struct rtable *rt;
1078
1079 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1080
1081 if (!fl4.flowi4_mark)
1082 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1083
1084 rt = __ip_route_output_key(sock_net(sk), &fl4);
1085 if (!IS_ERR(rt)) {
1086 __ip_rt_update_pmtu(rt, &fl4, mtu);
1087 ip_rt_put(rt);
1088 }
1089}
1090
1091void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1092{
1093 const struct iphdr *iph = (const struct iphdr *) skb->data;
1094 struct flowi4 fl4;
1095 struct rtable *rt;
1096 struct dst_entry *odst = NULL;
1097 bool new = false;
1098 struct net *net = sock_net(sk);
1099
1100 bh_lock_sock(sk);
1101
1102 if (!ip_sk_accept_pmtu(sk))
1103 goto out;
1104
1105 odst = sk_dst_get(sk);
1106
1107 if (sock_owned_by_user(sk) || !odst) {
1108 __ipv4_sk_update_pmtu(skb, sk, mtu);
1109 goto out;
1110 }
1111
1112 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1113
1114 rt = (struct rtable *)odst;
1115 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1116 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1117 if (IS_ERR(rt))
1118 goto out;
1119
1120 new = true;
1121 }
1122
1123 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1124
1125 if (!dst_check(&rt->dst, 0)) {
1126 if (new)
1127 dst_release(&rt->dst);
1128
1129 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1130 if (IS_ERR(rt))
1131 goto out;
1132
1133 new = true;
1134 }
1135
1136 if (new)
1137 sk_dst_set(sk, &rt->dst);
1138
1139out:
1140 bh_unlock_sock(sk);
1141 dst_release(odst);
1142}
1143EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1144
1145void ipv4_redirect(struct sk_buff *skb, struct net *net,
1146 int oif, u32 mark, u8 protocol, int flow_flags)
1147{
1148 const struct iphdr *iph = (const struct iphdr *) skb->data;
1149 struct flowi4 fl4;
1150 struct rtable *rt;
1151
1152 __build_flow_key(net, &fl4, NULL, iph, oif,
1153 RT_TOS(iph->tos), protocol, mark, flow_flags);
1154 rt = __ip_route_output_key(net, &fl4);
1155 if (!IS_ERR(rt)) {
1156 __ip_do_redirect(rt, skb, &fl4, false);
1157 ip_rt_put(rt);
1158 }
1159}
1160EXPORT_SYMBOL_GPL(ipv4_redirect);
1161
1162void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1163{
1164 const struct iphdr *iph = (const struct iphdr *) skb->data;
1165 struct flowi4 fl4;
1166 struct rtable *rt;
1167 struct net *net = sock_net(sk);
1168
1169 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1170 rt = __ip_route_output_key(net, &fl4);
1171 if (!IS_ERR(rt)) {
1172 __ip_do_redirect(rt, skb, &fl4, false);
1173 ip_rt_put(rt);
1174 }
1175}
1176EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1177
1178static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1179{
1180 struct rtable *rt = (struct rtable *) dst;
1181
1182 /* All IPV4 dsts are created with ->obsolete set to the value
1183 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1184 * into this function always.
1185 *
1186 * When a PMTU/redirect information update invalidates a route,
1187 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1188 * DST_OBSOLETE_DEAD by dst_free().
1189 */
1190 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1191 return NULL;
1192 return dst;
1193}
1194
1195static void ipv4_link_failure(struct sk_buff *skb)
1196{
1197 struct rtable *rt;
1198
1199 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
1200
1201 rt = skb_rtable(skb);
1202 if (rt)
1203 dst_set_expires(&rt->dst, 0);
1204}
1205
1206static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1207{
1208 pr_debug("%s: %pI4 -> %pI4, %s\n",
1209 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1210 skb->dev ? skb->dev->name : "?");
1211 kfree_skb(skb);
1212 WARN_ON(1);
1213 return 0;
1214}
1215
1216/*
1217 We do not cache source address of outgoing interface,
1218 because it is used only by IP RR, TS and SRR options,
1219 so that it out of fast path.
1220
1221 BTW remember: "addr" is allowed to be not aligned
1222 in IP options!
1223 */
1224
1225void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1226{
1227 __be32 src;
1228
1229 if (rt_is_output_route(rt))
1230 src = ip_hdr(skb)->saddr;
1231 else {
1232 struct fib_result res;
1233 struct flowi4 fl4;
1234 struct iphdr *iph;
1235
1236 iph = ip_hdr(skb);
1237
1238 memset(&fl4, 0, sizeof(fl4));
1239 fl4.daddr = iph->daddr;
1240 fl4.saddr = iph->saddr;
1241 fl4.flowi4_tos = RT_TOS(iph->tos);
1242 fl4.flowi4_oif = rt->dst.dev->ifindex;
1243 fl4.flowi4_iif = skb->dev->ifindex;
1244 fl4.flowi4_mark = skb->mark;
1245
1246 rcu_read_lock();
1247 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1248 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res);
1249 else
1250 src = inet_select_addr(rt->dst.dev,
1251 rt_nexthop(rt, iph->daddr),
1252 RT_SCOPE_UNIVERSE);
1253 rcu_read_unlock();
1254 }
1255 memcpy(addr, &src, 4);
1256}
1257
1258#ifdef CONFIG_IP_ROUTE_CLASSID
1259static void set_class_tag(struct rtable *rt, u32 tag)
1260{
1261 if (!(rt->dst.tclassid & 0xFFFF))
1262 rt->dst.tclassid |= tag & 0xFFFF;
1263 if (!(rt->dst.tclassid & 0xFFFF0000))
1264 rt->dst.tclassid |= tag & 0xFFFF0000;
1265}
1266#endif
1267
1268static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1269{
1270 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1271 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1272 ip_rt_min_advmss);
1273
1274 return min(advmss, IPV4_MAX_PMTU - header_size);
1275}
1276
1277static unsigned int ipv4_mtu(const struct dst_entry *dst)
1278{
1279 const struct rtable *rt = (const struct rtable *) dst;
1280 unsigned int mtu = rt->rt_pmtu;
1281
1282 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1283 mtu = dst_metric_raw(dst, RTAX_MTU);
1284
1285 if (mtu)
1286 return mtu;
1287
1288 mtu = READ_ONCE(dst->dev->mtu);
1289
1290 if (unlikely(ip_mtu_locked(dst))) {
1291 if (rt->rt_uses_gateway && mtu > 576)
1292 mtu = 576;
1293 }
1294
1295 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1296
1297 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1298}
1299
1300static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
1301{
1302 struct fnhe_hash_bucket *hash;
1303 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1304 u32 hval = fnhe_hashfun(daddr);
1305
1306 spin_lock_bh(&fnhe_lock);
1307
1308 hash = rcu_dereference_protected(nh->nh_exceptions,
1309 lockdep_is_held(&fnhe_lock));
1310 hash += hval;
1311
1312 fnhe_p = &hash->chain;
1313 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1314 while (fnhe) {
1315 if (fnhe->fnhe_daddr == daddr) {
1316 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1317 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1318 fnhe_flush_routes(fnhe);
1319 kfree_rcu(fnhe, rcu);
1320 break;
1321 }
1322 fnhe_p = &fnhe->fnhe_next;
1323 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1324 lockdep_is_held(&fnhe_lock));
1325 }
1326
1327 spin_unlock_bh(&fnhe_lock);
1328}
1329
1330static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
1331{
1332 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
1333 struct fib_nh_exception *fnhe;
1334 u32 hval;
1335
1336 if (!hash)
1337 return NULL;
1338
1339 hval = fnhe_hashfun(daddr);
1340
1341 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1342 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1343 if (fnhe->fnhe_daddr == daddr) {
1344 if (fnhe->fnhe_expires &&
1345 time_after(jiffies, fnhe->fnhe_expires)) {
1346 ip_del_fnhe(nh, daddr);
1347 break;
1348 }
1349 return fnhe;
1350 }
1351 }
1352 return NULL;
1353}
1354
1355static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1356 __be32 daddr, const bool do_cache)
1357{
1358 bool ret = false;
1359
1360 spin_lock_bh(&fnhe_lock);
1361
1362 if (daddr == fnhe->fnhe_daddr) {
1363 struct rtable __rcu **porig;
1364 struct rtable *orig;
1365 int genid = fnhe_genid(dev_net(rt->dst.dev));
1366
1367 if (rt_is_input_route(rt))
1368 porig = &fnhe->fnhe_rth_input;
1369 else
1370 porig = &fnhe->fnhe_rth_output;
1371 orig = rcu_dereference(*porig);
1372
1373 if (fnhe->fnhe_genid != genid) {
1374 fnhe->fnhe_genid = genid;
1375 fnhe->fnhe_gw = 0;
1376 fnhe->fnhe_pmtu = 0;
1377 fnhe->fnhe_expires = 0;
1378 fnhe->fnhe_mtu_locked = false;
1379 fnhe_flush_routes(fnhe);
1380 orig = NULL;
1381 }
1382 fill_route_from_fnhe(rt, fnhe);
1383 if (!rt->rt_gateway)
1384 rt->rt_gateway = daddr;
1385
1386 if (do_cache) {
1387 dst_hold(&rt->dst);
1388 rcu_assign_pointer(*porig, rt);
1389 if (orig) {
1390 dst_dev_put(&orig->dst);
1391 dst_release(&orig->dst);
1392 }
1393 ret = true;
1394 }
1395
1396 fnhe->fnhe_stamp = jiffies;
1397 }
1398 spin_unlock_bh(&fnhe_lock);
1399
1400 return ret;
1401}
1402
1403static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
1404{
1405 struct rtable *orig, *prev, **p;
1406 bool ret = true;
1407
1408 if (rt_is_input_route(rt)) {
1409 p = (struct rtable **)&nh->nh_rth_input;
1410 } else {
1411 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output);
1412 }
1413 orig = *p;
1414
1415 /* hold dst before doing cmpxchg() to avoid race condition
1416 * on this dst
1417 */
1418 dst_hold(&rt->dst);
1419 prev = cmpxchg(p, orig, rt);
1420 if (prev == orig) {
1421 if (orig) {
1422 dst_dev_put(&orig->dst);
1423 dst_release(&orig->dst);
1424 }
1425 } else {
1426 dst_release(&rt->dst);
1427 ret = false;
1428 }
1429
1430 return ret;
1431}
1432
1433struct uncached_list {
1434 spinlock_t lock;
1435 struct list_head head;
1436};
1437
1438static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1439
1440void rt_add_uncached_list(struct rtable *rt)
1441{
1442 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1443
1444 rt->rt_uncached_list = ul;
1445
1446 spin_lock_bh(&ul->lock);
1447 list_add_tail(&rt->rt_uncached, &ul->head);
1448 spin_unlock_bh(&ul->lock);
1449}
1450
1451void rt_del_uncached_list(struct rtable *rt)
1452{
1453 if (!list_empty(&rt->rt_uncached)) {
1454 struct uncached_list *ul = rt->rt_uncached_list;
1455
1456 spin_lock_bh(&ul->lock);
1457 list_del(&rt->rt_uncached);
1458 spin_unlock_bh(&ul->lock);
1459 }
1460}
1461
1462static void ipv4_dst_destroy(struct dst_entry *dst)
1463{
1464 struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
1465 struct rtable *rt = (struct rtable *)dst;
1466
1467 if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
1468 kfree(p);
1469
1470 rt_del_uncached_list(rt);
1471}
1472
1473void rt_flush_dev(struct net_device *dev)
1474{
1475 struct net *net = dev_net(dev);
1476 struct rtable *rt;
1477 int cpu;
1478
1479 for_each_possible_cpu(cpu) {
1480 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1481
1482 spin_lock_bh(&ul->lock);
1483 list_for_each_entry(rt, &ul->head, rt_uncached) {
1484 if (rt->dst.dev != dev)
1485 continue;
1486 rt->dst.dev = net->loopback_dev;
1487 dev_hold(rt->dst.dev);
1488 dev_put(dev);
1489 }
1490 spin_unlock_bh(&ul->lock);
1491 }
1492}
1493
1494static bool rt_cache_valid(const struct rtable *rt)
1495{
1496 return rt &&
1497 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1498 !rt_is_expired(rt);
1499}
1500
1501static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1502 const struct fib_result *res,
1503 struct fib_nh_exception *fnhe,
1504 struct fib_info *fi, u16 type, u32 itag,
1505 const bool do_cache)
1506{
1507 bool cached = false;
1508
1509 if (fi) {
1510 struct fib_nh *nh = &FIB_RES_NH(*res);
1511
1512 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) {
1513 rt->rt_gateway = nh->nh_gw;
1514 rt->rt_uses_gateway = 1;
1515 }
1516 dst_init_metrics(&rt->dst, fi->fib_metrics->metrics, true);
1517 if (fi->fib_metrics != &dst_default_metrics) {
1518 rt->dst._metrics |= DST_METRICS_REFCOUNTED;
1519 refcount_inc(&fi->fib_metrics->refcnt);
1520 }
1521#ifdef CONFIG_IP_ROUTE_CLASSID
1522 rt->dst.tclassid = nh->nh_tclassid;
1523#endif
1524 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
1525 if (unlikely(fnhe))
1526 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1527 else if (do_cache)
1528 cached = rt_cache_route(nh, rt);
1529 if (unlikely(!cached)) {
1530 /* Routes we intend to cache in nexthop exception or
1531 * FIB nexthop have the DST_NOCACHE bit clear.
1532 * However, if we are unsuccessful at storing this
1533 * route into the cache we really need to set it.
1534 */
1535 if (!rt->rt_gateway)
1536 rt->rt_gateway = daddr;
1537 rt_add_uncached_list(rt);
1538 }
1539 } else
1540 rt_add_uncached_list(rt);
1541
1542#ifdef CONFIG_IP_ROUTE_CLASSID
1543#ifdef CONFIG_IP_MULTIPLE_TABLES
1544 set_class_tag(rt, res->tclassid);
1545#endif
1546 set_class_tag(rt, itag);
1547#endif
1548}
1549
1550struct rtable *rt_dst_alloc(struct net_device *dev,
1551 unsigned int flags, u16 type,
1552 bool nopolicy, bool noxfrm, bool will_cache)
1553{
1554 struct rtable *rt;
1555
1556 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1557 (will_cache ? 0 : DST_HOST) |
1558 (nopolicy ? DST_NOPOLICY : 0) |
1559 (noxfrm ? DST_NOXFRM : 0));
1560
1561 if (rt) {
1562 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1563 rt->rt_flags = flags;
1564 rt->rt_type = type;
1565 rt->rt_is_input = 0;
1566 rt->rt_iif = 0;
1567 rt->rt_pmtu = 0;
1568 rt->rt_mtu_locked = 0;
1569 rt->rt_gateway = 0;
1570 rt->rt_uses_gateway = 0;
1571 INIT_LIST_HEAD(&rt->rt_uncached);
1572
1573 rt->dst.output = ip_output;
1574 if (flags & RTCF_LOCAL)
1575 rt->dst.input = ip_local_deliver;
1576 }
1577
1578 return rt;
1579}
1580EXPORT_SYMBOL(rt_dst_alloc);
1581
1582/* called in rcu_read_lock() section */
1583int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1584 u8 tos, struct net_device *dev,
1585 struct in_device *in_dev, u32 *itag)
1586{
1587 int err;
1588
1589 /* Primary sanity checks. */
1590 if (!in_dev)
1591 return -EINVAL;
1592
1593 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1594 skb->protocol != htons(ETH_P_IP))
1595 return -EINVAL;
1596
1597 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1598 return -EINVAL;
1599
1600 if (ipv4_is_zeronet(saddr)) {
1601 if (!ipv4_is_local_multicast(daddr))
1602 return -EINVAL;
1603 } else {
1604 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1605 in_dev, itag);
1606 if (err < 0)
1607 return err;
1608 }
1609 return 0;
1610}
1611
1612/* called in rcu_read_lock() section */
1613static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1614 u8 tos, struct net_device *dev, int our)
1615{
1616 struct in_device *in_dev = __in_dev_get_rcu(dev);
1617 unsigned int flags = RTCF_MULTICAST;
1618 struct rtable *rth;
1619 u32 itag = 0;
1620 int err;
1621
1622 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1623 if (err)
1624 return err;
1625
1626 if (our)
1627 flags |= RTCF_LOCAL;
1628
1629 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1630 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1631 if (!rth)
1632 return -ENOBUFS;
1633
1634#ifdef CONFIG_IP_ROUTE_CLASSID
1635 rth->dst.tclassid = itag;
1636#endif
1637 rth->dst.output = ip_rt_bug;
1638 rth->rt_is_input= 1;
1639
1640#ifdef CONFIG_IP_MROUTE
1641 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1642 rth->dst.input = ip_mr_input;
1643#endif
1644 RT_CACHE_STAT_INC(in_slow_mc);
1645
1646 skb_dst_set(skb, &rth->dst);
1647 return 0;
1648}
1649
1650
1651static void ip_handle_martian_source(struct net_device *dev,
1652 struct in_device *in_dev,
1653 struct sk_buff *skb,
1654 __be32 daddr,
1655 __be32 saddr)
1656{
1657 RT_CACHE_STAT_INC(in_martian_src);
1658#ifdef CONFIG_IP_ROUTE_VERBOSE
1659 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1660 /*
1661 * RFC1812 recommendation, if source is martian,
1662 * the only hint is MAC header.
1663 */
1664 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1665 &daddr, &saddr, dev->name);
1666 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1667 print_hex_dump(KERN_WARNING, "ll header: ",
1668 DUMP_PREFIX_OFFSET, 16, 1,
1669 skb_mac_header(skb),
1670 dev->hard_header_len, true);
1671 }
1672 }
1673#endif
1674}
1675
1676/* called in rcu_read_lock() section */
1677static int __mkroute_input(struct sk_buff *skb,
1678 const struct fib_result *res,
1679 struct in_device *in_dev,
1680 __be32 daddr, __be32 saddr, u32 tos)
1681{
1682 struct fib_nh_exception *fnhe;
1683 struct rtable *rth;
1684 int err;
1685 struct in_device *out_dev;
1686 bool do_cache;
1687 u32 itag = 0;
1688
1689 /* get a working reference to the output device */
1690 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res));
1691 if (!out_dev) {
1692 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1693 return -EINVAL;
1694 }
1695
1696 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1697 in_dev->dev, in_dev, &itag);
1698 if (err < 0) {
1699 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1700 saddr);
1701
1702 goto cleanup;
1703 }
1704
1705 do_cache = res->fi && !itag;
1706 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1707 skb->protocol == htons(ETH_P_IP) &&
1708 (IN_DEV_SHARED_MEDIA(out_dev) ||
1709 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
1710 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1711
1712 if (skb->protocol != htons(ETH_P_IP)) {
1713 /* Not IP (i.e. ARP). Do not create route, if it is
1714 * invalid for proxy arp. DNAT routes are always valid.
1715 *
1716 * Proxy arp feature have been extended to allow, ARP
1717 * replies back to the same interface, to support
1718 * Private VLAN switch technologies. See arp.c.
1719 */
1720 if (out_dev == in_dev &&
1721 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1722 err = -EINVAL;
1723 goto cleanup;
1724 }
1725 }
1726
1727 fnhe = find_exception(&FIB_RES_NH(*res), daddr);
1728 if (do_cache) {
1729 if (fnhe)
1730 rth = rcu_dereference(fnhe->fnhe_rth_input);
1731 else
1732 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
1733 if (rt_cache_valid(rth)) {
1734 skb_dst_set_noref(skb, &rth->dst);
1735 goto out;
1736 }
1737 }
1738
1739 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1740 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1741 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1742 if (!rth) {
1743 err = -ENOBUFS;
1744 goto cleanup;
1745 }
1746
1747 rth->rt_is_input = 1;
1748 RT_CACHE_STAT_INC(in_slow_tot);
1749
1750 rth->dst.input = ip_forward;
1751
1752 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1753 do_cache);
1754 lwtunnel_set_redirect(&rth->dst);
1755 skb_dst_set(skb, &rth->dst);
1756out:
1757 err = 0;
1758 cleanup:
1759 return err;
1760}
1761
1762#ifdef CONFIG_IP_ROUTE_MULTIPATH
1763/* To make ICMP packets follow the right flow, the multipath hash is
1764 * calculated from the inner IP addresses.
1765 */
1766static void ip_multipath_l3_keys(const struct sk_buff *skb,
1767 struct flow_keys *hash_keys)
1768{
1769 const struct iphdr *outer_iph = ip_hdr(skb);
1770 const struct iphdr *key_iph = outer_iph;
1771 const struct iphdr *inner_iph;
1772 const struct icmphdr *icmph;
1773 struct iphdr _inner_iph;
1774 struct icmphdr _icmph;
1775
1776 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1777 goto out;
1778
1779 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1780 goto out;
1781
1782 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1783 &_icmph);
1784 if (!icmph)
1785 goto out;
1786
1787 if (icmph->type != ICMP_DEST_UNREACH &&
1788 icmph->type != ICMP_REDIRECT &&
1789 icmph->type != ICMP_TIME_EXCEEDED &&
1790 icmph->type != ICMP_PARAMETERPROB)
1791 goto out;
1792
1793 inner_iph = skb_header_pointer(skb,
1794 outer_iph->ihl * 4 + sizeof(_icmph),
1795 sizeof(_inner_iph), &_inner_iph);
1796 if (!inner_iph)
1797 goto out;
1798
1799 key_iph = inner_iph;
1800out:
1801 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1802 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1803}
1804
1805/* if skb is set it will be used and fl4 can be NULL */
1806int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1807 const struct sk_buff *skb, struct flow_keys *flkeys)
1808{
1809 struct flow_keys hash_keys;
1810 u32 mhash;
1811
1812 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1813 case 0:
1814 memset(&hash_keys, 0, sizeof(hash_keys));
1815 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1816 if (skb) {
1817 ip_multipath_l3_keys(skb, &hash_keys);
1818 } else {
1819 hash_keys.addrs.v4addrs.src = fl4->saddr;
1820 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1821 }
1822 break;
1823 case 1:
1824 /* skb is currently provided only when forwarding */
1825 if (skb) {
1826 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1827 struct flow_keys keys;
1828
1829 /* short-circuit if we already have L4 hash present */
1830 if (skb->l4_hash)
1831 return skb_get_hash_raw(skb) >> 1;
1832
1833 memset(&hash_keys, 0, sizeof(hash_keys));
1834
1835 if (!flkeys) {
1836 skb_flow_dissect_flow_keys(skb, &keys, flag);
1837 flkeys = &keys;
1838 }
1839
1840 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1841 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1842 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1843 hash_keys.ports.src = flkeys->ports.src;
1844 hash_keys.ports.dst = flkeys->ports.dst;
1845 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1846 } else {
1847 memset(&hash_keys, 0, sizeof(hash_keys));
1848 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1849 hash_keys.addrs.v4addrs.src = fl4->saddr;
1850 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1851 hash_keys.ports.src = fl4->fl4_sport;
1852 hash_keys.ports.dst = fl4->fl4_dport;
1853 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1854 }
1855 break;
1856 }
1857 mhash = flow_hash_from_keys(&hash_keys);
1858
1859 return mhash >> 1;
1860}
1861#endif /* CONFIG_IP_ROUTE_MULTIPATH */
1862
1863static int ip_mkroute_input(struct sk_buff *skb,
1864 struct fib_result *res,
1865 struct in_device *in_dev,
1866 __be32 daddr, __be32 saddr, u32 tos,
1867 struct flow_keys *hkeys)
1868{
1869#ifdef CONFIG_IP_ROUTE_MULTIPATH
1870 if (res->fi && res->fi->fib_nhs > 1) {
1871 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
1872
1873 fib_select_multipath(res, h);
1874 }
1875#endif
1876
1877 /* create a routing cache entry */
1878 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
1879}
1880
1881/*
1882 * NOTE. We drop all the packets that has local source
1883 * addresses, because every properly looped back packet
1884 * must have correct destination already attached by output routine.
1885 *
1886 * Such approach solves two big problems:
1887 * 1. Not simplex devices are handled properly.
1888 * 2. IP spoofing attempts are filtered with 100% of guarantee.
1889 * called with rcu_read_lock()
1890 */
1891
1892static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1893 u8 tos, struct net_device *dev,
1894 struct fib_result *res)
1895{
1896 struct in_device *in_dev = __in_dev_get_rcu(dev);
1897 struct flow_keys *flkeys = NULL, _flkeys;
1898 struct net *net = dev_net(dev);
1899 struct ip_tunnel_info *tun_info;
1900 int err = -EINVAL;
1901 unsigned int flags = 0;
1902 u32 itag = 0;
1903 struct rtable *rth;
1904 struct flowi4 fl4;
1905 bool do_cache;
1906
1907 /* IP on this device is disabled. */
1908
1909 if (!in_dev)
1910 goto out;
1911
1912 /* Check for the most weird martians, which can be not detected
1913 by fib_lookup.
1914 */
1915
1916 tun_info = skb_tunnel_info(skb);
1917 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
1918 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
1919 else
1920 fl4.flowi4_tun_key.tun_id = 0;
1921 skb_dst_drop(skb);
1922
1923 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
1924 goto martian_source;
1925
1926 res->fi = NULL;
1927 res->table = NULL;
1928 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
1929 goto brd_input;
1930
1931 /* Accept zero addresses only to limited broadcast;
1932 * I even do not know to fix it or not. Waiting for complains :-)
1933 */
1934 if (ipv4_is_zeronet(saddr))
1935 goto martian_source;
1936
1937 if (ipv4_is_zeronet(daddr))
1938 goto martian_destination;
1939
1940 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
1941 * and call it once if daddr or/and saddr are loopback addresses
1942 */
1943 if (ipv4_is_loopback(daddr)) {
1944 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1945 goto martian_destination;
1946 } else if (ipv4_is_loopback(saddr)) {
1947 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
1948 goto martian_source;
1949 }
1950
1951 /*
1952 * Now we are ready to route packet.
1953 */
1954 fl4.flowi4_oif = 0;
1955 fl4.flowi4_iif = dev->ifindex;
1956 fl4.flowi4_mark = skb->mark;
1957 fl4.flowi4_tos = tos;
1958 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
1959 fl4.flowi4_flags = 0;
1960 fl4.daddr = daddr;
1961 fl4.saddr = saddr;
1962 fl4.flowi4_uid = sock_net_uid(net, NULL);
1963
1964 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
1965 flkeys = &_flkeys;
1966 } else {
1967 fl4.flowi4_proto = 0;
1968 fl4.fl4_sport = 0;
1969 fl4.fl4_dport = 0;
1970 }
1971
1972 err = fib_lookup(net, &fl4, res, 0);
1973 if (err != 0) {
1974 if (!IN_DEV_FORWARD(in_dev))
1975 err = -EHOSTUNREACH;
1976 goto no_route;
1977 }
1978
1979 if (res->type == RTN_BROADCAST)
1980 goto brd_input;
1981
1982 if (res->type == RTN_LOCAL) {
1983 err = fib_validate_source(skb, saddr, daddr, tos,
1984 0, dev, in_dev, &itag);
1985 if (err < 0)
1986 goto martian_source;
1987 goto local_input;
1988 }
1989
1990 if (!IN_DEV_FORWARD(in_dev)) {
1991 err = -EHOSTUNREACH;
1992 goto no_route;
1993 }
1994 if (res->type != RTN_UNICAST)
1995 goto martian_destination;
1996
1997 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
1998out: return err;
1999
2000brd_input:
2001 if (skb->protocol != htons(ETH_P_IP))
2002 goto e_inval;
2003
2004 if (!ipv4_is_zeronet(saddr)) {
2005 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2006 in_dev, &itag);
2007 if (err < 0)
2008 goto martian_source;
2009 }
2010 flags |= RTCF_BROADCAST;
2011 res->type = RTN_BROADCAST;
2012 RT_CACHE_STAT_INC(in_brd);
2013
2014local_input:
2015 do_cache = false;
2016 if (res->fi) {
2017 if (!itag) {
2018 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
2019 if (rt_cache_valid(rth)) {
2020 skb_dst_set_noref(skb, &rth->dst);
2021 err = 0;
2022 goto out;
2023 }
2024 do_cache = true;
2025 }
2026 }
2027
2028 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2029 flags | RTCF_LOCAL, res->type,
2030 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2031 if (!rth)
2032 goto e_nobufs;
2033
2034 rth->dst.output= ip_rt_bug;
2035#ifdef CONFIG_IP_ROUTE_CLASSID
2036 rth->dst.tclassid = itag;
2037#endif
2038 rth->rt_is_input = 1;
2039
2040 RT_CACHE_STAT_INC(in_slow_tot);
2041 if (res->type == RTN_UNREACHABLE) {
2042 rth->dst.input= ip_error;
2043 rth->dst.error= -err;
2044 rth->rt_flags &= ~RTCF_LOCAL;
2045 }
2046
2047 if (do_cache) {
2048 struct fib_nh *nh = &FIB_RES_NH(*res);
2049
2050 rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
2051 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2052 WARN_ON(rth->dst.input == lwtunnel_input);
2053 rth->dst.lwtstate->orig_input = rth->dst.input;
2054 rth->dst.input = lwtunnel_input;
2055 }
2056
2057 if (unlikely(!rt_cache_route(nh, rth)))
2058 rt_add_uncached_list(rth);
2059 }
2060 skb_dst_set(skb, &rth->dst);
2061 err = 0;
2062 goto out;
2063
2064no_route:
2065 RT_CACHE_STAT_INC(in_no_route);
2066 res->type = RTN_UNREACHABLE;
2067 res->fi = NULL;
2068 res->table = NULL;
2069 goto local_input;
2070
2071 /*
2072 * Do not cache martian addresses: they should be logged (RFC1812)
2073 */
2074martian_destination:
2075 RT_CACHE_STAT_INC(in_martian_dst);
2076#ifdef CONFIG_IP_ROUTE_VERBOSE
2077 if (IN_DEV_LOG_MARTIANS(in_dev))
2078 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2079 &daddr, &saddr, dev->name);
2080#endif
2081
2082e_inval:
2083 err = -EINVAL;
2084 goto out;
2085
2086e_nobufs:
2087 err = -ENOBUFS;
2088 goto out;
2089
2090martian_source:
2091 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2092 goto out;
2093}
2094
2095int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2096 u8 tos, struct net_device *dev)
2097{
2098 struct fib_result res;
2099 int err;
2100
2101 tos &= IPTOS_RT_MASK;
2102 rcu_read_lock();
2103 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2104 rcu_read_unlock();
2105
2106 return err;
2107}
2108EXPORT_SYMBOL(ip_route_input_noref);
2109
2110/* called with rcu_read_lock held */
2111int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2112 u8 tos, struct net_device *dev, struct fib_result *res)
2113{
2114 /* Multicast recognition logic is moved from route cache to here.
2115 The problem was that too many Ethernet cards have broken/missing
2116 hardware multicast filters :-( As result the host on multicasting
2117 network acquires a lot of useless route cache entries, sort of
2118 SDR messages from all the world. Now we try to get rid of them.
2119 Really, provided software IP multicast filter is organized
2120 reasonably (at least, hashed), it does not result in a slowdown
2121 comparing with route cache reject entries.
2122 Note, that multicast routers are not affected, because
2123 route cache entry is created eventually.
2124 */
2125 if (ipv4_is_multicast(daddr)) {
2126 struct in_device *in_dev = __in_dev_get_rcu(dev);
2127 int our = 0;
2128 int err = -EINVAL;
2129
2130 if (in_dev)
2131 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2132 ip_hdr(skb)->protocol);
2133
2134 /* check l3 master if no match yet */
2135 if ((!in_dev || !our) && netif_is_l3_slave(dev)) {
2136 struct in_device *l3_in_dev;
2137
2138 l3_in_dev = __in_dev_get_rcu(skb->dev);
2139 if (l3_in_dev)
2140 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2141 ip_hdr(skb)->protocol);
2142 }
2143
2144 if (our
2145#ifdef CONFIG_IP_MROUTE
2146 ||
2147 (!ipv4_is_local_multicast(daddr) &&
2148 IN_DEV_MFORWARD(in_dev))
2149#endif
2150 ) {
2151 err = ip_route_input_mc(skb, daddr, saddr,
2152 tos, dev, our);
2153 }
2154 return err;
2155 }
2156
2157 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2158}
2159
2160/* called with rcu_read_lock() */
2161static struct rtable *__mkroute_output(const struct fib_result *res,
2162 const struct flowi4 *fl4, int orig_oif,
2163 struct net_device *dev_out,
2164 unsigned int flags)
2165{
2166 struct fib_info *fi = res->fi;
2167 struct fib_nh_exception *fnhe;
2168 struct in_device *in_dev;
2169 u16 type = res->type;
2170 struct rtable *rth;
2171 bool do_cache;
2172
2173 in_dev = __in_dev_get_rcu(dev_out);
2174 if (!in_dev)
2175 return ERR_PTR(-EINVAL);
2176
2177 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2178 if (ipv4_is_loopback(fl4->saddr) &&
2179 !(dev_out->flags & IFF_LOOPBACK) &&
2180 !netif_is_l3_master(dev_out))
2181 return ERR_PTR(-EINVAL);
2182
2183 if (ipv4_is_lbcast(fl4->daddr))
2184 type = RTN_BROADCAST;
2185 else if (ipv4_is_multicast(fl4->daddr))
2186 type = RTN_MULTICAST;
2187 else if (ipv4_is_zeronet(fl4->daddr))
2188 return ERR_PTR(-EINVAL);
2189
2190 if (dev_out->flags & IFF_LOOPBACK)
2191 flags |= RTCF_LOCAL;
2192
2193 do_cache = true;
2194 if (type == RTN_BROADCAST) {
2195 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2196 fi = NULL;
2197 } else if (type == RTN_MULTICAST) {
2198 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2199 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2200 fl4->flowi4_proto))
2201 flags &= ~RTCF_LOCAL;
2202 else
2203 do_cache = false;
2204 /* If multicast route do not exist use
2205 * default one, but do not gateway in this case.
2206 * Yes, it is hack.
2207 */
2208 if (fi && res->prefixlen < 4)
2209 fi = NULL;
2210 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2211 (orig_oif != dev_out->ifindex)) {
2212 /* For local routes that require a particular output interface
2213 * we do not want to cache the result. Caching the result
2214 * causes incorrect behaviour when there are multiple source
2215 * addresses on the interface, the end result being that if the
2216 * intended recipient is waiting on that interface for the
2217 * packet he won't receive it because it will be delivered on
2218 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2219 * be set to the loopback interface as well.
2220 */
2221 do_cache = false;
2222 }
2223
2224 fnhe = NULL;
2225 do_cache &= fi != NULL;
2226 if (fi) {
2227 struct rtable __rcu **prth;
2228 struct fib_nh *nh = &FIB_RES_NH(*res);
2229
2230 fnhe = find_exception(nh, fl4->daddr);
2231 if (!do_cache)
2232 goto add;
2233 if (fnhe) {
2234 prth = &fnhe->fnhe_rth_output;
2235 } else {
2236 if (unlikely(fl4->flowi4_flags &
2237 FLOWI_FLAG_KNOWN_NH &&
2238 !(nh->nh_gw &&
2239 nh->nh_scope == RT_SCOPE_LINK))) {
2240 do_cache = false;
2241 goto add;
2242 }
2243 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
2244 }
2245 rth = rcu_dereference(*prth);
2246 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2247 return rth;
2248 }
2249
2250add:
2251 rth = rt_dst_alloc(dev_out, flags, type,
2252 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2253 IN_DEV_CONF_GET(in_dev, NOXFRM),
2254 do_cache);
2255 if (!rth)
2256 return ERR_PTR(-ENOBUFS);
2257
2258 rth->rt_iif = orig_oif;
2259
2260 RT_CACHE_STAT_INC(out_slow_tot);
2261
2262 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2263 if (flags & RTCF_LOCAL &&
2264 !(dev_out->flags & IFF_LOOPBACK)) {
2265 rth->dst.output = ip_mc_output;
2266 RT_CACHE_STAT_INC(out_slow_mc);
2267 }
2268#ifdef CONFIG_IP_MROUTE
2269 if (type == RTN_MULTICAST) {
2270 if (IN_DEV_MFORWARD(in_dev) &&
2271 !ipv4_is_local_multicast(fl4->daddr)) {
2272 rth->dst.input = ip_mr_input;
2273 rth->dst.output = ip_mc_output;
2274 }
2275 }
2276#endif
2277 }
2278
2279 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2280 lwtunnel_set_redirect(&rth->dst);
2281
2282 return rth;
2283}
2284
2285/*
2286 * Major route resolver routine.
2287 */
2288
2289struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2290 const struct sk_buff *skb)
2291{
2292 __u8 tos = RT_FL_TOS(fl4);
2293 struct fib_result res = {
2294 .type = RTN_UNSPEC,
2295 .fi = NULL,
2296 .table = NULL,
2297 .tclassid = 0,
2298 };
2299 struct rtable *rth;
2300
2301 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2302 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2303 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2304 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2305
2306 rcu_read_lock();
2307 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2308 rcu_read_unlock();
2309
2310 return rth;
2311}
2312EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2313
2314struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2315 struct fib_result *res,
2316 const struct sk_buff *skb)
2317{
2318 struct net_device *dev_out = NULL;
2319 int orig_oif = fl4->flowi4_oif;
2320 unsigned int flags = 0;
2321 struct rtable *rth;
2322 int err = -ENETUNREACH;
2323
2324 if (fl4->saddr) {
2325 rth = ERR_PTR(-EINVAL);
2326 if (ipv4_is_multicast(fl4->saddr) ||
2327 ipv4_is_lbcast(fl4->saddr) ||
2328 ipv4_is_zeronet(fl4->saddr))
2329 goto out;
2330
2331 /* I removed check for oif == dev_out->oif here.
2332 It was wrong for two reasons:
2333 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2334 is assigned to multiple interfaces.
2335 2. Moreover, we are allowed to send packets with saddr
2336 of another iface. --ANK
2337 */
2338
2339 if (fl4->flowi4_oif == 0 &&
2340 (ipv4_is_multicast(fl4->daddr) ||
2341 ipv4_is_lbcast(fl4->daddr))) {
2342 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2343 dev_out = __ip_dev_find(net, fl4->saddr, false);
2344 if (!dev_out)
2345 goto out;
2346
2347 /* Special hack: user can direct multicasts
2348 and limited broadcast via necessary interface
2349 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2350 This hack is not just for fun, it allows
2351 vic,vat and friends to work.
2352 They bind socket to loopback, set ttl to zero
2353 and expect that it will work.
2354 From the viewpoint of routing cache they are broken,
2355 because we are not allowed to build multicast path
2356 with loopback source addr (look, routing cache
2357 cannot know, that ttl is zero, so that packet
2358 will not leave this host and route is valid).
2359 Luckily, this hack is good workaround.
2360 */
2361
2362 fl4->flowi4_oif = dev_out->ifindex;
2363 goto make_route;
2364 }
2365
2366 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2367 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2368 if (!__ip_dev_find(net, fl4->saddr, false))
2369 goto out;
2370 }
2371 }
2372
2373
2374 if (fl4->flowi4_oif) {
2375 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2376 rth = ERR_PTR(-ENODEV);
2377 if (!dev_out)
2378 goto out;
2379
2380 /* RACE: Check return value of inet_select_addr instead. */
2381 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2382 rth = ERR_PTR(-ENETUNREACH);
2383 goto out;
2384 }
2385 if (ipv4_is_local_multicast(fl4->daddr) ||
2386 ipv4_is_lbcast(fl4->daddr) ||
2387 fl4->flowi4_proto == IPPROTO_IGMP) {
2388 if (!fl4->saddr)
2389 fl4->saddr = inet_select_addr(dev_out, 0,
2390 RT_SCOPE_LINK);
2391 goto make_route;
2392 }
2393 if (!fl4->saddr) {
2394 if (ipv4_is_multicast(fl4->daddr))
2395 fl4->saddr = inet_select_addr(dev_out, 0,
2396 fl4->flowi4_scope);
2397 else if (!fl4->daddr)
2398 fl4->saddr = inet_select_addr(dev_out, 0,
2399 RT_SCOPE_HOST);
2400 }
2401 }
2402
2403 if (!fl4->daddr) {
2404 fl4->daddr = fl4->saddr;
2405 if (!fl4->daddr)
2406 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2407 dev_out = net->loopback_dev;
2408 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2409 res->type = RTN_LOCAL;
2410 flags |= RTCF_LOCAL;
2411 goto make_route;
2412 }
2413
2414 err = fib_lookup(net, fl4, res, 0);
2415 if (err) {
2416 res->fi = NULL;
2417 res->table = NULL;
2418 if (fl4->flowi4_oif &&
2419 (ipv4_is_multicast(fl4->daddr) ||
2420 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2421 /* Apparently, routing tables are wrong. Assume,
2422 that the destination is on link.
2423
2424 WHY? DW.
2425 Because we are allowed to send to iface
2426 even if it has NO routes and NO assigned
2427 addresses. When oif is specified, routing
2428 tables are looked up with only one purpose:
2429 to catch if destination is gatewayed, rather than
2430 direct. Moreover, if MSG_DONTROUTE is set,
2431 we send packet, ignoring both routing tables
2432 and ifaddr state. --ANK
2433
2434
2435 We could make it even if oif is unknown,
2436 likely IPv6, but we do not.
2437 */
2438
2439 if (fl4->saddr == 0)
2440 fl4->saddr = inet_select_addr(dev_out, 0,
2441 RT_SCOPE_LINK);
2442 res->type = RTN_UNICAST;
2443 goto make_route;
2444 }
2445 rth = ERR_PTR(err);
2446 goto out;
2447 }
2448
2449 if (res->type == RTN_LOCAL) {
2450 if (!fl4->saddr) {
2451 if (res->fi->fib_prefsrc)
2452 fl4->saddr = res->fi->fib_prefsrc;
2453 else
2454 fl4->saddr = fl4->daddr;
2455 }
2456
2457 /* L3 master device is the loopback for that domain */
2458 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2459 net->loopback_dev;
2460
2461 /* make sure orig_oif points to fib result device even
2462 * though packet rx/tx happens over loopback or l3mdev
2463 */
2464 orig_oif = FIB_RES_OIF(*res);
2465
2466 fl4->flowi4_oif = dev_out->ifindex;
2467 flags |= RTCF_LOCAL;
2468 goto make_route;
2469 }
2470
2471 fib_select_path(net, res, fl4, skb);
2472
2473 dev_out = FIB_RES_DEV(*res);
2474 fl4->flowi4_oif = dev_out->ifindex;
2475
2476
2477make_route:
2478 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2479
2480out:
2481 return rth;
2482}
2483
2484static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2485{
2486 return NULL;
2487}
2488
2489static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2490{
2491 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2492
2493 return mtu ? : dst->dev->mtu;
2494}
2495
2496static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2497 struct sk_buff *skb, u32 mtu)
2498{
2499}
2500
2501static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2502 struct sk_buff *skb)
2503{
2504}
2505
2506static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2507 unsigned long old)
2508{
2509 return NULL;
2510}
2511
2512static struct dst_ops ipv4_dst_blackhole_ops = {
2513 .family = AF_INET,
2514 .check = ipv4_blackhole_dst_check,
2515 .mtu = ipv4_blackhole_mtu,
2516 .default_advmss = ipv4_default_advmss,
2517 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2518 .redirect = ipv4_rt_blackhole_redirect,
2519 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2520 .neigh_lookup = ipv4_neigh_lookup,
2521};
2522
2523struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2524{
2525 struct rtable *ort = (struct rtable *) dst_orig;
2526 struct rtable *rt;
2527
2528 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2529 if (rt) {
2530 struct dst_entry *new = &rt->dst;
2531
2532 new->__use = 1;
2533 new->input = dst_discard;
2534 new->output = dst_discard_out;
2535
2536 new->dev = net->loopback_dev;
2537 if (new->dev)
2538 dev_hold(new->dev);
2539
2540 rt->rt_is_input = ort->rt_is_input;
2541 rt->rt_iif = ort->rt_iif;
2542 rt->rt_pmtu = ort->rt_pmtu;
2543 rt->rt_mtu_locked = ort->rt_mtu_locked;
2544
2545 rt->rt_genid = rt_genid_ipv4(net);
2546 rt->rt_flags = ort->rt_flags;
2547 rt->rt_type = ort->rt_type;
2548 rt->rt_gateway = ort->rt_gateway;
2549 rt->rt_uses_gateway = ort->rt_uses_gateway;
2550
2551 INIT_LIST_HEAD(&rt->rt_uncached);
2552 }
2553
2554 dst_release(dst_orig);
2555
2556 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2557}
2558
2559struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2560 const struct sock *sk)
2561{
2562 struct rtable *rt = __ip_route_output_key(net, flp4);
2563
2564 if (IS_ERR(rt))
2565 return rt;
2566
2567 if (flp4->flowi4_proto)
2568 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2569 flowi4_to_flowi(flp4),
2570 sk, 0);
2571
2572 return rt;
2573}
2574EXPORT_SYMBOL_GPL(ip_route_output_flow);
2575
2576/* called with rcu_read_lock held */
2577static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id,
2578 struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2579 u32 seq)
2580{
2581 struct rtable *rt = skb_rtable(skb);
2582 struct rtmsg *r;
2583 struct nlmsghdr *nlh;
2584 unsigned long expires = 0;
2585 u32 error;
2586 u32 metrics[RTAX_MAX];
2587
2588 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
2589 if (!nlh)
2590 return -EMSGSIZE;
2591
2592 r = nlmsg_data(nlh);
2593 r->rtm_family = AF_INET;
2594 r->rtm_dst_len = 32;
2595 r->rtm_src_len = 0;
2596 r->rtm_tos = fl4->flowi4_tos;
2597 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2598 if (nla_put_u32(skb, RTA_TABLE, table_id))
2599 goto nla_put_failure;
2600 r->rtm_type = rt->rt_type;
2601 r->rtm_scope = RT_SCOPE_UNIVERSE;
2602 r->rtm_protocol = RTPROT_UNSPEC;
2603 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2604 if (rt->rt_flags & RTCF_NOTIFY)
2605 r->rtm_flags |= RTM_F_NOTIFY;
2606 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2607 r->rtm_flags |= RTCF_DOREDIRECT;
2608
2609 if (nla_put_in_addr(skb, RTA_DST, dst))
2610 goto nla_put_failure;
2611 if (src) {
2612 r->rtm_src_len = 32;
2613 if (nla_put_in_addr(skb, RTA_SRC, src))
2614 goto nla_put_failure;
2615 }
2616 if (rt->dst.dev &&
2617 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2618 goto nla_put_failure;
2619#ifdef CONFIG_IP_ROUTE_CLASSID
2620 if (rt->dst.tclassid &&
2621 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2622 goto nla_put_failure;
2623#endif
2624 if (!rt_is_input_route(rt) &&
2625 fl4->saddr != src) {
2626 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2627 goto nla_put_failure;
2628 }
2629 if (rt->rt_uses_gateway &&
2630 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
2631 goto nla_put_failure;
2632
2633 expires = rt->dst.expires;
2634 if (expires) {
2635 unsigned long now = jiffies;
2636
2637 if (time_before(now, expires))
2638 expires -= now;
2639 else
2640 expires = 0;
2641 }
2642
2643 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2644 if (rt->rt_pmtu && expires)
2645 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2646 if (rt->rt_mtu_locked && expires)
2647 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2648 if (rtnetlink_put_metrics(skb, metrics) < 0)
2649 goto nla_put_failure;
2650
2651 if (fl4->flowi4_mark &&
2652 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2653 goto nla_put_failure;
2654
2655 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2656 nla_put_u32(skb, RTA_UID,
2657 from_kuid_munged(current_user_ns(), fl4->flowi4_uid)))
2658 goto nla_put_failure;
2659
2660 error = rt->dst.error;
2661
2662 if (rt_is_input_route(rt)) {
2663#ifdef CONFIG_IP_MROUTE
2664 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) &&
2665 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2666 int err = ipmr_get_route(net, skb,
2667 fl4->saddr, fl4->daddr,
2668 r, portid);
2669
2670 if (err <= 0) {
2671 if (err == 0)
2672 return 0;
2673 goto nla_put_failure;
2674 }
2675 } else
2676#endif
2677 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex))
2678 goto nla_put_failure;
2679 }
2680
2681 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2682 goto nla_put_failure;
2683
2684 nlmsg_end(skb, nlh);
2685 return 0;
2686
2687nla_put_failure:
2688 nlmsg_cancel(skb, nlh);
2689 return -EMSGSIZE;
2690}
2691
2692static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
2693 struct netlink_ext_ack *extack)
2694{
2695 struct net *net = sock_net(in_skb->sk);
2696 struct rtmsg *rtm;
2697 struct nlattr *tb[RTA_MAX+1];
2698 struct fib_result res = {};
2699 struct rtable *rt = NULL;
2700 struct flowi4 fl4;
2701 __be32 dst = 0;
2702 __be32 src = 0;
2703 u32 iif;
2704 int err;
2705 int mark;
2706 struct sk_buff *skb;
2707 u32 table_id = RT_TABLE_MAIN;
2708 kuid_t uid;
2709
2710 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy,
2711 extack);
2712 if (err < 0)
2713 goto errout;
2714
2715 rtm = nlmsg_data(nlh);
2716
2717 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2718 if (!skb) {
2719 err = -ENOBUFS;
2720 goto errout;
2721 }
2722
2723 /* Reserve room for dummy headers, this skb can pass
2724 through good chunk of routing engine.
2725 */
2726 skb_reset_mac_header(skb);
2727 skb_reset_network_header(skb);
2728
2729 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
2730 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
2731 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
2732 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
2733 if (tb[RTA_UID])
2734 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
2735 else
2736 uid = (iif ? INVALID_UID : current_uid());
2737
2738 /* Bugfix: need to give ip_route_input enough of an IP header to
2739 * not gag.
2740 */
2741 ip_hdr(skb)->protocol = IPPROTO_UDP;
2742 ip_hdr(skb)->saddr = src;
2743 ip_hdr(skb)->daddr = dst;
2744
2745 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));
2746
2747 memset(&fl4, 0, sizeof(fl4));
2748 fl4.daddr = dst;
2749 fl4.saddr = src;
2750 fl4.flowi4_tos = rtm->rtm_tos;
2751 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
2752 fl4.flowi4_mark = mark;
2753 fl4.flowi4_uid = uid;
2754
2755 rcu_read_lock();
2756
2757 if (iif) {
2758 struct net_device *dev;
2759
2760 dev = dev_get_by_index_rcu(net, iif);
2761 if (!dev) {
2762 err = -ENODEV;
2763 goto errout_free;
2764 }
2765
2766 skb->protocol = htons(ETH_P_IP);
2767 skb->dev = dev;
2768 skb->mark = mark;
2769 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
2770 dev, &res);
2771
2772 rt = skb_rtable(skb);
2773 if (err == 0 && rt->dst.error)
2774 err = -rt->dst.error;
2775 } else {
2776 fl4.flowi4_iif = LOOPBACK_IFINDEX;
2777 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
2778 err = 0;
2779 if (IS_ERR(rt))
2780 err = PTR_ERR(rt);
2781 else
2782 skb_dst_set(skb, &rt->dst);
2783 }
2784
2785 if (err)
2786 goto errout_free;
2787
2788 if (rtm->rtm_flags & RTM_F_NOTIFY)
2789 rt->rt_flags |= RTCF_NOTIFY;
2790
2791 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
2792 table_id = res.table ? res.table->tb_id : 0;
2793
2794 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2795 if (!res.fi) {
2796 err = fib_props[res.type].error;
2797 if (!err)
2798 err = -EHOSTUNREACH;
2799 goto errout_free;
2800 }
2801 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
2802 nlh->nlmsg_seq, RTM_NEWROUTE, table_id,
2803 rt->rt_type, res.prefix, res.prefixlen,
2804 fl4.flowi4_tos, res.fi, 0);
2805 } else {
2806 err = rt_fill_info(net, dst, src, table_id, &fl4, skb,
2807 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
2808 }
2809 if (err < 0)
2810 goto errout_free;
2811
2812 rcu_read_unlock();
2813
2814 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
2815errout:
2816 return err;
2817
2818errout_free:
2819 rcu_read_unlock();
2820 kfree_skb(skb);
2821 goto errout;
2822}
2823
2824void ip_rt_multicast_event(struct in_device *in_dev)
2825{
2826 rt_cache_flush(dev_net(in_dev->dev));
2827}
2828
2829#ifdef CONFIG_SYSCTL
2830static int ip_rt_gc_interval __read_mostly = 60 * HZ;
2831static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
2832static int ip_rt_gc_elasticity __read_mostly = 8;
2833static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
2834
2835static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
2836 void __user *buffer,
2837 size_t *lenp, loff_t *ppos)
2838{
2839 struct net *net = (struct net *)__ctl->extra1;
2840
2841 if (write) {
2842 rt_cache_flush(net);
2843 fnhe_genid_bump(net);
2844 return 0;
2845 }
2846
2847 return -EINVAL;
2848}
2849
2850static struct ctl_table ipv4_route_table[] = {
2851 {
2852 .procname = "gc_thresh",
2853 .data = &ipv4_dst_ops.gc_thresh,
2854 .maxlen = sizeof(int),
2855 .mode = 0644,
2856 .proc_handler = proc_dointvec,
2857 },
2858 {
2859 .procname = "max_size",
2860 .data = &ip_rt_max_size,
2861 .maxlen = sizeof(int),
2862 .mode = 0644,
2863 .proc_handler = proc_dointvec,
2864 },
2865 {
2866 /* Deprecated. Use gc_min_interval_ms */
2867
2868 .procname = "gc_min_interval",
2869 .data = &ip_rt_gc_min_interval,
2870 .maxlen = sizeof(int),
2871 .mode = 0644,
2872 .proc_handler = proc_dointvec_jiffies,
2873 },
2874 {
2875 .procname = "gc_min_interval_ms",
2876 .data = &ip_rt_gc_min_interval,
2877 .maxlen = sizeof(int),
2878 .mode = 0644,
2879 .proc_handler = proc_dointvec_ms_jiffies,
2880 },
2881 {
2882 .procname = "gc_timeout",
2883 .data = &ip_rt_gc_timeout,
2884 .maxlen = sizeof(int),
2885 .mode = 0644,
2886 .proc_handler = proc_dointvec_jiffies,
2887 },
2888 {
2889 .procname = "gc_interval",
2890 .data = &ip_rt_gc_interval,
2891 .maxlen = sizeof(int),
2892 .mode = 0644,
2893 .proc_handler = proc_dointvec_jiffies,
2894 },
2895 {
2896 .procname = "redirect_load",
2897 .data = &ip_rt_redirect_load,
2898 .maxlen = sizeof(int),
2899 .mode = 0644,
2900 .proc_handler = proc_dointvec,
2901 },
2902 {
2903 .procname = "redirect_number",
2904 .data = &ip_rt_redirect_number,
2905 .maxlen = sizeof(int),
2906 .mode = 0644,
2907 .proc_handler = proc_dointvec,
2908 },
2909 {
2910 .procname = "redirect_silence",
2911 .data = &ip_rt_redirect_silence,
2912 .maxlen = sizeof(int),
2913 .mode = 0644,
2914 .proc_handler = proc_dointvec,
2915 },
2916 {
2917 .procname = "error_cost",
2918 .data = &ip_rt_error_cost,
2919 .maxlen = sizeof(int),
2920 .mode = 0644,
2921 .proc_handler = proc_dointvec,
2922 },
2923 {
2924 .procname = "error_burst",
2925 .data = &ip_rt_error_burst,
2926 .maxlen = sizeof(int),
2927 .mode = 0644,
2928 .proc_handler = proc_dointvec,
2929 },
2930 {
2931 .procname = "gc_elasticity",
2932 .data = &ip_rt_gc_elasticity,
2933 .maxlen = sizeof(int),
2934 .mode = 0644,
2935 .proc_handler = proc_dointvec,
2936 },
2937 {
2938 .procname = "mtu_expires",
2939 .data = &ip_rt_mtu_expires,
2940 .maxlen = sizeof(int),
2941 .mode = 0644,
2942 .proc_handler = proc_dointvec_jiffies,
2943 },
2944 {
2945 .procname = "min_pmtu",
2946 .data = &ip_rt_min_pmtu,
2947 .maxlen = sizeof(int),
2948 .mode = 0644,
2949 .proc_handler = proc_dointvec_minmax,
2950 .extra1 = &ip_min_valid_pmtu,
2951 },
2952 {
2953 .procname = "min_adv_mss",
2954 .data = &ip_rt_min_advmss,
2955 .maxlen = sizeof(int),
2956 .mode = 0644,
2957 .proc_handler = proc_dointvec,
2958 },
2959 { }
2960};
2961
2962static struct ctl_table ipv4_route_flush_table[] = {
2963 {
2964 .procname = "flush",
2965 .maxlen = sizeof(int),
2966 .mode = 0200,
2967 .proc_handler = ipv4_sysctl_rtcache_flush,
2968 },
2969 { },
2970};
2971
2972static __net_init int sysctl_route_net_init(struct net *net)
2973{
2974 struct ctl_table *tbl;
2975
2976 tbl = ipv4_route_flush_table;
2977 if (!net_eq(net, &init_net)) {
2978 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
2979 if (!tbl)
2980 goto err_dup;
2981
2982 /* Don't export sysctls to unprivileged users */
2983 if (net->user_ns != &init_user_ns)
2984 tbl[0].procname = NULL;
2985 }
2986 tbl[0].extra1 = net;
2987
2988 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
2989 if (!net->ipv4.route_hdr)
2990 goto err_reg;
2991 return 0;
2992
2993err_reg:
2994 if (tbl != ipv4_route_flush_table)
2995 kfree(tbl);
2996err_dup:
2997 return -ENOMEM;
2998}
2999
3000static __net_exit void sysctl_route_net_exit(struct net *net)
3001{
3002 struct ctl_table *tbl;
3003
3004 tbl = net->ipv4.route_hdr->ctl_table_arg;
3005 unregister_net_sysctl_table(net->ipv4.route_hdr);
3006 BUG_ON(tbl == ipv4_route_flush_table);
3007 kfree(tbl);
3008}
3009
3010static __net_initdata struct pernet_operations sysctl_route_ops = {
3011 .init = sysctl_route_net_init,
3012 .exit = sysctl_route_net_exit,
3013};
3014#endif
3015
3016static __net_init int rt_genid_init(struct net *net)
3017{
3018 atomic_set(&net->ipv4.rt_genid, 0);
3019 atomic_set(&net->fnhe_genid, 0);
3020 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3021 return 0;
3022}
3023
3024static __net_initdata struct pernet_operations rt_genid_ops = {
3025 .init = rt_genid_init,
3026};
3027
3028static int __net_init ipv4_inetpeer_init(struct net *net)
3029{
3030 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3031
3032 if (!bp)
3033 return -ENOMEM;
3034 inet_peer_base_init(bp);
3035 net->ipv4.peers = bp;
3036 return 0;
3037}
3038
3039static void __net_exit ipv4_inetpeer_exit(struct net *net)
3040{
3041 struct inet_peer_base *bp = net->ipv4.peers;
3042
3043 net->ipv4.peers = NULL;
3044 inetpeer_invalidate_tree(bp);
3045 kfree(bp);
3046}
3047
3048static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3049 .init = ipv4_inetpeer_init,
3050 .exit = ipv4_inetpeer_exit,
3051};
3052
3053#ifdef CONFIG_IP_ROUTE_CLASSID
3054struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3055#endif /* CONFIG_IP_ROUTE_CLASSID */
3056
3057int __init ip_rt_init(void)
3058{
3059 int cpu;
3060
3061 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL);
3062 if (!ip_idents)
3063 panic("IP: failed to allocate ip_idents\n");
3064
3065 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3066
3067 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3068 if (!ip_tstamps)
3069 panic("IP: failed to allocate ip_tstamps\n");
3070
3071 for_each_possible_cpu(cpu) {
3072 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3073
3074 INIT_LIST_HEAD(&ul->head);
3075 spin_lock_init(&ul->lock);
3076 }
3077#ifdef CONFIG_IP_ROUTE_CLASSID
3078 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3079 if (!ip_rt_acct)
3080 panic("IP: failed to allocate ip_rt_acct\n");
3081#endif
3082
3083 ipv4_dst_ops.kmem_cachep =
3084 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3085 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3086
3087 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3088
3089 if (dst_entries_init(&ipv4_dst_ops) < 0)
3090 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3091
3092 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3093 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3094
3095 ipv4_dst_ops.gc_thresh = ~0;
3096 ip_rt_max_size = INT_MAX;
3097
3098 devinet_init();
3099 ip_fib_init();
3100
3101 if (ip_rt_proc_init())
3102 pr_err("Unable to create route proc files\n");
3103#ifdef CONFIG_XFRM
3104 xfrm_init();
3105 xfrm4_init();
3106#endif
3107 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3108 RTNL_FLAG_DOIT_UNLOCKED);
3109
3110#ifdef CONFIG_SYSCTL
3111 register_pernet_subsys(&sysctl_route_ops);
3112#endif
3113 register_pernet_subsys(&rt_genid_ops);
3114 register_pernet_subsys(&ipv4_inetpeer_ops);
3115 return 0;
3116}
3117
3118#ifdef CONFIG_SYSCTL
3119/*
3120 * We really need to sanitize the damn ipv4 init order, then all
3121 * this nonsense will go away.
3122 */
3123void __init ip_static_sysctl_init(void)
3124{
3125 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3126}
3127#endif
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * ROUTE - implementation of the IP router.
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Alan Cox, <gw4pts@gw4pts.ampr.org>
12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
14 *
15 * Fixes:
16 * Alan Cox : Verify area fixes.
17 * Alan Cox : cli() protects routing changes
18 * Rui Oliveira : ICMP routing table updates
19 * (rco@di.uminho.pt) Routing table insertion and update
20 * Linus Torvalds : Rewrote bits to be sensible
21 * Alan Cox : Added BSD route gw semantics
22 * Alan Cox : Super /proc >4K
23 * Alan Cox : MTU in route table
24 * Alan Cox : MSS actually. Also added the window
25 * clamper.
26 * Sam Lantinga : Fixed route matching in rt_del()
27 * Alan Cox : Routing cache support.
28 * Alan Cox : Removed compatibility cruft.
29 * Alan Cox : RTF_REJECT support.
30 * Alan Cox : TCP irtt support.
31 * Jonathan Naylor : Added Metric support.
32 * Miquel van Smoorenburg : BSD API fixes.
33 * Miquel van Smoorenburg : Metrics.
34 * Alan Cox : Use __u32 properly
35 * Alan Cox : Aligned routing errors more closely with BSD
36 * our system is still very different.
37 * Alan Cox : Faster /proc handling
38 * Alexey Kuznetsov : Massive rework to support tree based routing,
39 * routing caches and better behaviour.
40 *
41 * Olaf Erb : irtt wasn't being copied right.
42 * Bjorn Ekwall : Kerneld route support.
43 * Alan Cox : Multicast fixed (I hope)
44 * Pavel Krauz : Limited broadcast fixed
45 * Mike McLagan : Routing by source
46 * Alexey Kuznetsov : End of old history. Split to fib.c and
47 * route.c and rewritten from scratch.
48 * Andi Kleen : Load-limit warning messages.
49 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
53 * Marc Boucher : routing by fwmark
54 * Robert Olsson : Added rt_cache statistics
55 * Arnaldo C. Melo : Convert proc stuff to seq_file
56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
58 * Ilia Sotnikov : Removed TOS from hash calculations
59 */
60
61#define pr_fmt(fmt) "IPv4: " fmt
62
63#include <linux/module.h>
64#include <linux/bitops.h>
65#include <linux/kernel.h>
66#include <linux/mm.h>
67#include <linux/memblock.h>
68#include <linux/socket.h>
69#include <linux/errno.h>
70#include <linux/in.h>
71#include <linux/inet.h>
72#include <linux/netdevice.h>
73#include <linux/proc_fs.h>
74#include <linux/init.h>
75#include <linux/skbuff.h>
76#include <linux/inetdevice.h>
77#include <linux/igmp.h>
78#include <linux/pkt_sched.h>
79#include <linux/mroute.h>
80#include <linux/netfilter_ipv4.h>
81#include <linux/random.h>
82#include <linux/rcupdate.h>
83#include <linux/slab.h>
84#include <linux/jhash.h>
85#include <net/dst.h>
86#include <net/dst_metadata.h>
87#include <net/inet_dscp.h>
88#include <net/net_namespace.h>
89#include <net/ip.h>
90#include <net/route.h>
91#include <net/inetpeer.h>
92#include <net/sock.h>
93#include <net/ip_fib.h>
94#include <net/nexthop.h>
95#include <net/tcp.h>
96#include <net/icmp.h>
97#include <net/xfrm.h>
98#include <net/lwtunnel.h>
99#include <net/netevent.h>
100#include <net/rtnetlink.h>
101#ifdef CONFIG_SYSCTL
102#include <linux/sysctl.h>
103#endif
104#include <net/secure_seq.h>
105#include <net/ip_tunnels.h>
106
107#include "fib_lookup.h"
108
109#define RT_FL_TOS(oldflp4) \
110 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
111
112#define RT_GC_TIMEOUT (300*HZ)
113
114#define DEFAULT_MIN_PMTU (512 + 20 + 20)
115#define DEFAULT_MTU_EXPIRES (10 * 60 * HZ)
116#define DEFAULT_MIN_ADVMSS 256
117static int ip_rt_max_size;
118static int ip_rt_redirect_number __read_mostly = 9;
119static int ip_rt_redirect_load __read_mostly = HZ / 50;
120static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
121static int ip_rt_error_cost __read_mostly = HZ;
122static int ip_rt_error_burst __read_mostly = 5 * HZ;
123
124static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
125
126/*
127 * Interface to generic destination cache.
128 */
129
130INDIRECT_CALLABLE_SCOPE
131struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
132static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
133INDIRECT_CALLABLE_SCOPE
134unsigned int ipv4_mtu(const struct dst_entry *dst);
135static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
136static void ipv4_link_failure(struct sk_buff *skb);
137static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
138 struct sk_buff *skb, u32 mtu,
139 bool confirm_neigh);
140static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
141 struct sk_buff *skb);
142static void ipv4_dst_destroy(struct dst_entry *dst);
143
144static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
145{
146 WARN_ON(1);
147 return NULL;
148}
149
150static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
151 struct sk_buff *skb,
152 const void *daddr);
153static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
154
155static struct dst_ops ipv4_dst_ops = {
156 .family = AF_INET,
157 .check = ipv4_dst_check,
158 .default_advmss = ipv4_default_advmss,
159 .mtu = ipv4_mtu,
160 .cow_metrics = ipv4_cow_metrics,
161 .destroy = ipv4_dst_destroy,
162 .negative_advice = ipv4_negative_advice,
163 .link_failure = ipv4_link_failure,
164 .update_pmtu = ip_rt_update_pmtu,
165 .redirect = ip_do_redirect,
166 .local_out = __ip_local_out,
167 .neigh_lookup = ipv4_neigh_lookup,
168 .confirm_neigh = ipv4_confirm_neigh,
169};
170
171#define ECN_OR_COST(class) TC_PRIO_##class
172
173const __u8 ip_tos2prio[16] = {
174 TC_PRIO_BESTEFFORT,
175 ECN_OR_COST(BESTEFFORT),
176 TC_PRIO_BESTEFFORT,
177 ECN_OR_COST(BESTEFFORT),
178 TC_PRIO_BULK,
179 ECN_OR_COST(BULK),
180 TC_PRIO_BULK,
181 ECN_OR_COST(BULK),
182 TC_PRIO_INTERACTIVE,
183 ECN_OR_COST(INTERACTIVE),
184 TC_PRIO_INTERACTIVE,
185 ECN_OR_COST(INTERACTIVE),
186 TC_PRIO_INTERACTIVE_BULK,
187 ECN_OR_COST(INTERACTIVE_BULK),
188 TC_PRIO_INTERACTIVE_BULK,
189 ECN_OR_COST(INTERACTIVE_BULK)
190};
191EXPORT_SYMBOL(ip_tos2prio);
192
193static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
194#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
195
196#ifdef CONFIG_PROC_FS
197static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
198{
199 if (*pos)
200 return NULL;
201 return SEQ_START_TOKEN;
202}
203
204static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
205{
206 ++*pos;
207 return NULL;
208}
209
210static void rt_cache_seq_stop(struct seq_file *seq, void *v)
211{
212}
213
214static int rt_cache_seq_show(struct seq_file *seq, void *v)
215{
216 if (v == SEQ_START_TOKEN)
217 seq_printf(seq, "%-127s\n",
218 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
219 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
220 "HHUptod\tSpecDst");
221 return 0;
222}
223
224static const struct seq_operations rt_cache_seq_ops = {
225 .start = rt_cache_seq_start,
226 .next = rt_cache_seq_next,
227 .stop = rt_cache_seq_stop,
228 .show = rt_cache_seq_show,
229};
230
231static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
232{
233 int cpu;
234
235 if (*pos == 0)
236 return SEQ_START_TOKEN;
237
238 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
239 if (!cpu_possible(cpu))
240 continue;
241 *pos = cpu+1;
242 return &per_cpu(rt_cache_stat, cpu);
243 }
244 return NULL;
245}
246
247static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
248{
249 int cpu;
250
251 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
252 if (!cpu_possible(cpu))
253 continue;
254 *pos = cpu+1;
255 return &per_cpu(rt_cache_stat, cpu);
256 }
257 (*pos)++;
258 return NULL;
259
260}
261
262static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
263{
264
265}
266
267static int rt_cpu_seq_show(struct seq_file *seq, void *v)
268{
269 struct rt_cache_stat *st = v;
270
271 if (v == SEQ_START_TOKEN) {
272 seq_puts(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
273 return 0;
274 }
275
276 seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x "
277 "%08x %08x %08x %08x %08x %08x "
278 "%08x %08x %08x %08x\n",
279 dst_entries_get_slow(&ipv4_dst_ops),
280 0, /* st->in_hit */
281 st->in_slow_tot,
282 st->in_slow_mc,
283 st->in_no_route,
284 st->in_brd,
285 st->in_martian_dst,
286 st->in_martian_src,
287
288 0, /* st->out_hit */
289 st->out_slow_tot,
290 st->out_slow_mc,
291
292 0, /* st->gc_total */
293 0, /* st->gc_ignored */
294 0, /* st->gc_goal_miss */
295 0, /* st->gc_dst_overflow */
296 0, /* st->in_hlist_search */
297 0 /* st->out_hlist_search */
298 );
299 return 0;
300}
301
302static const struct seq_operations rt_cpu_seq_ops = {
303 .start = rt_cpu_seq_start,
304 .next = rt_cpu_seq_next,
305 .stop = rt_cpu_seq_stop,
306 .show = rt_cpu_seq_show,
307};
308
309#ifdef CONFIG_IP_ROUTE_CLASSID
310static int rt_acct_proc_show(struct seq_file *m, void *v)
311{
312 struct ip_rt_acct *dst, *src;
313 unsigned int i, j;
314
315 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
316 if (!dst)
317 return -ENOMEM;
318
319 for_each_possible_cpu(i) {
320 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
321 for (j = 0; j < 256; j++) {
322 dst[j].o_bytes += src[j].o_bytes;
323 dst[j].o_packets += src[j].o_packets;
324 dst[j].i_bytes += src[j].i_bytes;
325 dst[j].i_packets += src[j].i_packets;
326 }
327 }
328
329 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
330 kfree(dst);
331 return 0;
332}
333#endif
334
335static int __net_init ip_rt_do_proc_init(struct net *net)
336{
337 struct proc_dir_entry *pde;
338
339 pde = proc_create_seq("rt_cache", 0444, net->proc_net,
340 &rt_cache_seq_ops);
341 if (!pde)
342 goto err1;
343
344 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
345 &rt_cpu_seq_ops);
346 if (!pde)
347 goto err2;
348
349#ifdef CONFIG_IP_ROUTE_CLASSID
350 pde = proc_create_single("rt_acct", 0, net->proc_net,
351 rt_acct_proc_show);
352 if (!pde)
353 goto err3;
354#endif
355 return 0;
356
357#ifdef CONFIG_IP_ROUTE_CLASSID
358err3:
359 remove_proc_entry("rt_cache", net->proc_net_stat);
360#endif
361err2:
362 remove_proc_entry("rt_cache", net->proc_net);
363err1:
364 return -ENOMEM;
365}
366
367static void __net_exit ip_rt_do_proc_exit(struct net *net)
368{
369 remove_proc_entry("rt_cache", net->proc_net_stat);
370 remove_proc_entry("rt_cache", net->proc_net);
371#ifdef CONFIG_IP_ROUTE_CLASSID
372 remove_proc_entry("rt_acct", net->proc_net);
373#endif
374}
375
376static struct pernet_operations ip_rt_proc_ops __net_initdata = {
377 .init = ip_rt_do_proc_init,
378 .exit = ip_rt_do_proc_exit,
379};
380
381static int __init ip_rt_proc_init(void)
382{
383 return register_pernet_subsys(&ip_rt_proc_ops);
384}
385
386#else
387static inline int ip_rt_proc_init(void)
388{
389 return 0;
390}
391#endif /* CONFIG_PROC_FS */
392
393static inline bool rt_is_expired(const struct rtable *rth)
394{
395 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
396}
397
398void rt_cache_flush(struct net *net)
399{
400 rt_genid_bump_ipv4(net);
401}
402
403static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
404 struct sk_buff *skb,
405 const void *daddr)
406{
407 const struct rtable *rt = container_of(dst, struct rtable, dst);
408 struct net_device *dev = dst->dev;
409 struct neighbour *n;
410
411 rcu_read_lock();
412
413 if (likely(rt->rt_gw_family == AF_INET)) {
414 n = ip_neigh_gw4(dev, rt->rt_gw4);
415 } else if (rt->rt_gw_family == AF_INET6) {
416 n = ip_neigh_gw6(dev, &rt->rt_gw6);
417 } else {
418 __be32 pkey;
419
420 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
421 n = ip_neigh_gw4(dev, pkey);
422 }
423
424 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
425 n = NULL;
426
427 rcu_read_unlock();
428
429 return n;
430}
431
432static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
433{
434 const struct rtable *rt = container_of(dst, struct rtable, dst);
435 struct net_device *dev = dst->dev;
436 const __be32 *pkey = daddr;
437
438 if (rt->rt_gw_family == AF_INET) {
439 pkey = (const __be32 *)&rt->rt_gw4;
440 } else if (rt->rt_gw_family == AF_INET6) {
441 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
442 } else if (!daddr ||
443 (rt->rt_flags &
444 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
445 return;
446 }
447 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
448}
449
450/* Hash tables of size 2048..262144 depending on RAM size.
451 * Each bucket uses 8 bytes.
452 */
453static u32 ip_idents_mask __read_mostly;
454static atomic_t *ip_idents __read_mostly;
455static u32 *ip_tstamps __read_mostly;
456
457/* In order to protect privacy, we add a perturbation to identifiers
458 * if one generator is seldom used. This makes hard for an attacker
459 * to infer how many packets were sent between two points in time.
460 */
461static u32 ip_idents_reserve(u32 hash, int segs)
462{
463 u32 bucket, old, now = (u32)jiffies;
464 atomic_t *p_id;
465 u32 *p_tstamp;
466 u32 delta = 0;
467
468 bucket = hash & ip_idents_mask;
469 p_tstamp = ip_tstamps + bucket;
470 p_id = ip_idents + bucket;
471 old = READ_ONCE(*p_tstamp);
472
473 if (old != now && cmpxchg(p_tstamp, old, now) == old)
474 delta = get_random_u32_below(now - old);
475
476 /* If UBSAN reports an error there, please make sure your compiler
477 * supports -fno-strict-overflow before reporting it that was a bug
478 * in UBSAN, and it has been fixed in GCC-8.
479 */
480 return atomic_add_return(segs + delta, p_id) - segs;
481}
482
483void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
484{
485 u32 hash, id;
486
487 /* Note the following code is not safe, but this is okay. */
488 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
489 get_random_bytes(&net->ipv4.ip_id_key,
490 sizeof(net->ipv4.ip_id_key));
491
492 hash = siphash_3u32((__force u32)iph->daddr,
493 (__force u32)iph->saddr,
494 iph->protocol,
495 &net->ipv4.ip_id_key);
496 id = ip_idents_reserve(hash, segs);
497 iph->id = htons(id);
498}
499EXPORT_SYMBOL(__ip_select_ident);
500
501static void ip_rt_fix_tos(struct flowi4 *fl4)
502{
503 __u8 tos = RT_FL_TOS(fl4);
504
505 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
506 if (tos & RTO_ONLINK)
507 fl4->flowi4_scope = RT_SCOPE_LINK;
508}
509
510static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
511 const struct sock *sk, const struct iphdr *iph,
512 int oif, __u8 tos, u8 prot, u32 mark,
513 int flow_flags)
514{
515 __u8 scope = RT_SCOPE_UNIVERSE;
516
517 if (sk) {
518 oif = sk->sk_bound_dev_if;
519 mark = READ_ONCE(sk->sk_mark);
520 tos = ip_sock_rt_tos(sk);
521 scope = ip_sock_rt_scope(sk);
522 prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW :
523 sk->sk_protocol;
524 }
525
526 flowi4_init_output(fl4, oif, mark, tos & IPTOS_RT_MASK, scope,
527 prot, flow_flags, iph->daddr, iph->saddr, 0, 0,
528 sock_net_uid(net, sk));
529}
530
531static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
532 const struct sock *sk)
533{
534 const struct net *net = dev_net(skb->dev);
535 const struct iphdr *iph = ip_hdr(skb);
536 int oif = skb->dev->ifindex;
537 u8 prot = iph->protocol;
538 u32 mark = skb->mark;
539 __u8 tos = iph->tos;
540
541 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
542}
543
544static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
545{
546 const struct inet_sock *inet = inet_sk(sk);
547 const struct ip_options_rcu *inet_opt;
548 __be32 daddr = inet->inet_daddr;
549
550 rcu_read_lock();
551 inet_opt = rcu_dereference(inet->inet_opt);
552 if (inet_opt && inet_opt->opt.srr)
553 daddr = inet_opt->opt.faddr;
554 flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark),
555 ip_sock_rt_tos(sk) & IPTOS_RT_MASK,
556 ip_sock_rt_scope(sk),
557 inet_test_bit(HDRINCL, sk) ?
558 IPPROTO_RAW : sk->sk_protocol,
559 inet_sk_flowi_flags(sk),
560 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
561 rcu_read_unlock();
562}
563
564static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
565 const struct sk_buff *skb)
566{
567 if (skb)
568 build_skb_flow_key(fl4, skb, sk);
569 else
570 build_sk_flow_key(fl4, sk);
571}
572
573static DEFINE_SPINLOCK(fnhe_lock);
574
575static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
576{
577 struct rtable *rt;
578
579 rt = rcu_dereference(fnhe->fnhe_rth_input);
580 if (rt) {
581 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
582 dst_dev_put(&rt->dst);
583 dst_release(&rt->dst);
584 }
585 rt = rcu_dereference(fnhe->fnhe_rth_output);
586 if (rt) {
587 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
588 dst_dev_put(&rt->dst);
589 dst_release(&rt->dst);
590 }
591}
592
593static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
594{
595 struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
596 struct fib_nh_exception *fnhe, *oldest = NULL;
597
598 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
599 fnhe = rcu_dereference_protected(*fnhe_p,
600 lockdep_is_held(&fnhe_lock));
601 if (!fnhe)
602 break;
603 if (!oldest ||
604 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
605 oldest = fnhe;
606 oldest_p = fnhe_p;
607 }
608 }
609 fnhe_flush_routes(oldest);
610 *oldest_p = oldest->fnhe_next;
611 kfree_rcu(oldest, rcu);
612}
613
614static u32 fnhe_hashfun(__be32 daddr)
615{
616 static siphash_aligned_key_t fnhe_hash_key;
617 u64 hval;
618
619 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
620 hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key);
621 return hash_64(hval, FNHE_HASH_SHIFT);
622}
623
624static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
625{
626 rt->rt_pmtu = fnhe->fnhe_pmtu;
627 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
628 rt->dst.expires = fnhe->fnhe_expires;
629
630 if (fnhe->fnhe_gw) {
631 rt->rt_flags |= RTCF_REDIRECTED;
632 rt->rt_uses_gateway = 1;
633 rt->rt_gw_family = AF_INET;
634 rt->rt_gw4 = fnhe->fnhe_gw;
635 }
636}
637
638static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
639 __be32 gw, u32 pmtu, bool lock,
640 unsigned long expires)
641{
642 struct fnhe_hash_bucket *hash;
643 struct fib_nh_exception *fnhe;
644 struct rtable *rt;
645 u32 genid, hval;
646 unsigned int i;
647 int depth;
648
649 genid = fnhe_genid(dev_net(nhc->nhc_dev));
650 hval = fnhe_hashfun(daddr);
651
652 spin_lock_bh(&fnhe_lock);
653
654 hash = rcu_dereference(nhc->nhc_exceptions);
655 if (!hash) {
656 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
657 if (!hash)
658 goto out_unlock;
659 rcu_assign_pointer(nhc->nhc_exceptions, hash);
660 }
661
662 hash += hval;
663
664 depth = 0;
665 for (fnhe = rcu_dereference(hash->chain); fnhe;
666 fnhe = rcu_dereference(fnhe->fnhe_next)) {
667 if (fnhe->fnhe_daddr == daddr)
668 break;
669 depth++;
670 }
671
672 if (fnhe) {
673 if (fnhe->fnhe_genid != genid)
674 fnhe->fnhe_genid = genid;
675 if (gw)
676 fnhe->fnhe_gw = gw;
677 if (pmtu) {
678 fnhe->fnhe_pmtu = pmtu;
679 fnhe->fnhe_mtu_locked = lock;
680 }
681 fnhe->fnhe_expires = max(1UL, expires);
682 /* Update all cached dsts too */
683 rt = rcu_dereference(fnhe->fnhe_rth_input);
684 if (rt)
685 fill_route_from_fnhe(rt, fnhe);
686 rt = rcu_dereference(fnhe->fnhe_rth_output);
687 if (rt)
688 fill_route_from_fnhe(rt, fnhe);
689 } else {
690 /* Randomize max depth to avoid some side channels attacks. */
691 int max_depth = FNHE_RECLAIM_DEPTH +
692 get_random_u32_below(FNHE_RECLAIM_DEPTH);
693
694 while (depth > max_depth) {
695 fnhe_remove_oldest(hash);
696 depth--;
697 }
698
699 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
700 if (!fnhe)
701 goto out_unlock;
702
703 fnhe->fnhe_next = hash->chain;
704
705 fnhe->fnhe_genid = genid;
706 fnhe->fnhe_daddr = daddr;
707 fnhe->fnhe_gw = gw;
708 fnhe->fnhe_pmtu = pmtu;
709 fnhe->fnhe_mtu_locked = lock;
710 fnhe->fnhe_expires = max(1UL, expires);
711
712 rcu_assign_pointer(hash->chain, fnhe);
713
714 /* Exception created; mark the cached routes for the nexthop
715 * stale, so anyone caching it rechecks if this exception
716 * applies to them.
717 */
718 rt = rcu_dereference(nhc->nhc_rth_input);
719 if (rt)
720 rt->dst.obsolete = DST_OBSOLETE_KILL;
721
722 for_each_possible_cpu(i) {
723 struct rtable __rcu **prt;
724
725 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
726 rt = rcu_dereference(*prt);
727 if (rt)
728 rt->dst.obsolete = DST_OBSOLETE_KILL;
729 }
730 }
731
732 fnhe->fnhe_stamp = jiffies;
733
734out_unlock:
735 spin_unlock_bh(&fnhe_lock);
736}
737
738static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
739 bool kill_route)
740{
741 __be32 new_gw = icmp_hdr(skb)->un.gateway;
742 __be32 old_gw = ip_hdr(skb)->saddr;
743 struct net_device *dev = skb->dev;
744 struct in_device *in_dev;
745 struct fib_result res;
746 struct neighbour *n;
747 struct net *net;
748
749 switch (icmp_hdr(skb)->code & 7) {
750 case ICMP_REDIR_NET:
751 case ICMP_REDIR_NETTOS:
752 case ICMP_REDIR_HOST:
753 case ICMP_REDIR_HOSTTOS:
754 break;
755
756 default:
757 return;
758 }
759
760 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
761 return;
762
763 in_dev = __in_dev_get_rcu(dev);
764 if (!in_dev)
765 return;
766
767 net = dev_net(dev);
768 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
769 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
770 ipv4_is_zeronet(new_gw))
771 goto reject_redirect;
772
773 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
774 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
775 goto reject_redirect;
776 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
777 goto reject_redirect;
778 } else {
779 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
780 goto reject_redirect;
781 }
782
783 n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw);
784 if (!n)
785 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
786 if (!IS_ERR(n)) {
787 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
788 neigh_event_send(n, NULL);
789 } else {
790 if (fib_lookup(net, fl4, &res, 0) == 0) {
791 struct fib_nh_common *nhc;
792
793 fib_select_path(net, &res, fl4, skb);
794 nhc = FIB_RES_NHC(res);
795 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
796 0, false,
797 jiffies + ip_rt_gc_timeout);
798 }
799 if (kill_route)
800 rt->dst.obsolete = DST_OBSOLETE_KILL;
801 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
802 }
803 neigh_release(n);
804 }
805 return;
806
807reject_redirect:
808#ifdef CONFIG_IP_ROUTE_VERBOSE
809 if (IN_DEV_LOG_MARTIANS(in_dev)) {
810 const struct iphdr *iph = (const struct iphdr *) skb->data;
811 __be32 daddr = iph->daddr;
812 __be32 saddr = iph->saddr;
813
814 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
815 " Advised path = %pI4 -> %pI4\n",
816 &old_gw, dev->name, &new_gw,
817 &saddr, &daddr);
818 }
819#endif
820 ;
821}
822
823static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
824{
825 struct rtable *rt;
826 struct flowi4 fl4;
827 const struct iphdr *iph = (const struct iphdr *) skb->data;
828 struct net *net = dev_net(skb->dev);
829 int oif = skb->dev->ifindex;
830 u8 prot = iph->protocol;
831 u32 mark = skb->mark;
832 __u8 tos = iph->tos;
833
834 rt = (struct rtable *) dst;
835
836 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
837 __ip_do_redirect(rt, skb, &fl4, true);
838}
839
840static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
841{
842 struct rtable *rt = (struct rtable *)dst;
843 struct dst_entry *ret = dst;
844
845 if (rt) {
846 if (dst->obsolete > 0) {
847 ip_rt_put(rt);
848 ret = NULL;
849 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
850 rt->dst.expires) {
851 ip_rt_put(rt);
852 ret = NULL;
853 }
854 }
855 return ret;
856}
857
858/*
859 * Algorithm:
860 * 1. The first ip_rt_redirect_number redirects are sent
861 * with exponential backoff, then we stop sending them at all,
862 * assuming that the host ignores our redirects.
863 * 2. If we did not see packets requiring redirects
864 * during ip_rt_redirect_silence, we assume that the host
865 * forgot redirected route and start to send redirects again.
866 *
867 * This algorithm is much cheaper and more intelligent than dumb load limiting
868 * in icmp.c.
869 *
870 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
871 * and "frag. need" (breaks PMTU discovery) in icmp.c.
872 */
873
874void ip_rt_send_redirect(struct sk_buff *skb)
875{
876 struct rtable *rt = skb_rtable(skb);
877 struct in_device *in_dev;
878 struct inet_peer *peer;
879 struct net *net;
880 int log_martians;
881 int vif;
882
883 rcu_read_lock();
884 in_dev = __in_dev_get_rcu(rt->dst.dev);
885 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
886 rcu_read_unlock();
887 return;
888 }
889 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
890 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
891 rcu_read_unlock();
892
893 net = dev_net(rt->dst.dev);
894 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
895 if (!peer) {
896 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
897 rt_nexthop(rt, ip_hdr(skb)->daddr));
898 return;
899 }
900
901 /* No redirected packets during ip_rt_redirect_silence;
902 * reset the algorithm.
903 */
904 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
905 peer->rate_tokens = 0;
906 peer->n_redirects = 0;
907 }
908
909 /* Too many ignored redirects; do not send anything
910 * set dst.rate_last to the last seen redirected packet.
911 */
912 if (peer->n_redirects >= ip_rt_redirect_number) {
913 peer->rate_last = jiffies;
914 goto out_put_peer;
915 }
916
917 /* Check for load limit; set rate_last to the latest sent
918 * redirect.
919 */
920 if (peer->n_redirects == 0 ||
921 time_after(jiffies,
922 (peer->rate_last +
923 (ip_rt_redirect_load << peer->n_redirects)))) {
924 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
925
926 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
927 peer->rate_last = jiffies;
928 ++peer->n_redirects;
929#ifdef CONFIG_IP_ROUTE_VERBOSE
930 if (log_martians &&
931 peer->n_redirects == ip_rt_redirect_number)
932 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
933 &ip_hdr(skb)->saddr, inet_iif(skb),
934 &ip_hdr(skb)->daddr, &gw);
935#endif
936 }
937out_put_peer:
938 inet_putpeer(peer);
939}
940
941static int ip_error(struct sk_buff *skb)
942{
943 struct rtable *rt = skb_rtable(skb);
944 struct net_device *dev = skb->dev;
945 struct in_device *in_dev;
946 struct inet_peer *peer;
947 unsigned long now;
948 struct net *net;
949 SKB_DR(reason);
950 bool send;
951 int code;
952
953 if (netif_is_l3_master(skb->dev)) {
954 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
955 if (!dev)
956 goto out;
957 }
958
959 in_dev = __in_dev_get_rcu(dev);
960
961 /* IP on this device is disabled. */
962 if (!in_dev)
963 goto out;
964
965 net = dev_net(rt->dst.dev);
966 if (!IN_DEV_FORWARD(in_dev)) {
967 switch (rt->dst.error) {
968 case EHOSTUNREACH:
969 SKB_DR_SET(reason, IP_INADDRERRORS);
970 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
971 break;
972
973 case ENETUNREACH:
974 SKB_DR_SET(reason, IP_INNOROUTES);
975 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
976 break;
977 }
978 goto out;
979 }
980
981 switch (rt->dst.error) {
982 case EINVAL:
983 default:
984 goto out;
985 case EHOSTUNREACH:
986 code = ICMP_HOST_UNREACH;
987 break;
988 case ENETUNREACH:
989 code = ICMP_NET_UNREACH;
990 SKB_DR_SET(reason, IP_INNOROUTES);
991 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
992 break;
993 case EACCES:
994 code = ICMP_PKT_FILTERED;
995 break;
996 }
997
998 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
999 l3mdev_master_ifindex(skb->dev), 1);
1000
1001 send = true;
1002 if (peer) {
1003 now = jiffies;
1004 peer->rate_tokens += now - peer->rate_last;
1005 if (peer->rate_tokens > ip_rt_error_burst)
1006 peer->rate_tokens = ip_rt_error_burst;
1007 peer->rate_last = now;
1008 if (peer->rate_tokens >= ip_rt_error_cost)
1009 peer->rate_tokens -= ip_rt_error_cost;
1010 else
1011 send = false;
1012 inet_putpeer(peer);
1013 }
1014 if (send)
1015 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1016
1017out: kfree_skb_reason(skb, reason);
1018 return 0;
1019}
1020
1021static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1022{
1023 struct dst_entry *dst = &rt->dst;
1024 struct net *net = dev_net(dst->dev);
1025 struct fib_result res;
1026 bool lock = false;
1027 u32 old_mtu;
1028
1029 if (ip_mtu_locked(dst))
1030 return;
1031
1032 old_mtu = ipv4_mtu(dst);
1033 if (old_mtu < mtu)
1034 return;
1035
1036 if (mtu < net->ipv4.ip_rt_min_pmtu) {
1037 lock = true;
1038 mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
1039 }
1040
1041 if (rt->rt_pmtu == mtu && !lock &&
1042 time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
1043 return;
1044
1045 rcu_read_lock();
1046 if (fib_lookup(net, fl4, &res, 0) == 0) {
1047 struct fib_nh_common *nhc;
1048
1049 fib_select_path(net, &res, fl4, NULL);
1050 nhc = FIB_RES_NHC(res);
1051 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1052 jiffies + net->ipv4.ip_rt_mtu_expires);
1053 }
1054 rcu_read_unlock();
1055}
1056
1057static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1058 struct sk_buff *skb, u32 mtu,
1059 bool confirm_neigh)
1060{
1061 struct rtable *rt = (struct rtable *) dst;
1062 struct flowi4 fl4;
1063
1064 ip_rt_build_flow_key(&fl4, sk, skb);
1065
1066 /* Don't make lookup fail for bridged encapsulations */
1067 if (skb && netif_is_any_bridge_port(skb->dev))
1068 fl4.flowi4_oif = 0;
1069
1070 __ip_rt_update_pmtu(rt, &fl4, mtu);
1071}
1072
1073void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1074 int oif, u8 protocol)
1075{
1076 const struct iphdr *iph = (const struct iphdr *)skb->data;
1077 struct flowi4 fl4;
1078 struct rtable *rt;
1079 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1080
1081 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, mark,
1082 0);
1083 rt = __ip_route_output_key(net, &fl4);
1084 if (!IS_ERR(rt)) {
1085 __ip_rt_update_pmtu(rt, &fl4, mtu);
1086 ip_rt_put(rt);
1087 }
1088}
1089EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1090
1091static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1092{
1093 const struct iphdr *iph = (const struct iphdr *)skb->data;
1094 struct flowi4 fl4;
1095 struct rtable *rt;
1096
1097 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1098
1099 if (!fl4.flowi4_mark)
1100 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1101
1102 rt = __ip_route_output_key(sock_net(sk), &fl4);
1103 if (!IS_ERR(rt)) {
1104 __ip_rt_update_pmtu(rt, &fl4, mtu);
1105 ip_rt_put(rt);
1106 }
1107}
1108
1109void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1110{
1111 const struct iphdr *iph = (const struct iphdr *)skb->data;
1112 struct flowi4 fl4;
1113 struct rtable *rt;
1114 struct dst_entry *odst = NULL;
1115 bool new = false;
1116 struct net *net = sock_net(sk);
1117
1118 bh_lock_sock(sk);
1119
1120 if (!ip_sk_accept_pmtu(sk))
1121 goto out;
1122
1123 odst = sk_dst_get(sk);
1124
1125 if (sock_owned_by_user(sk) || !odst) {
1126 __ipv4_sk_update_pmtu(skb, sk, mtu);
1127 goto out;
1128 }
1129
1130 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1131
1132 rt = (struct rtable *)odst;
1133 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1134 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1135 if (IS_ERR(rt))
1136 goto out;
1137
1138 new = true;
1139 }
1140
1141 __ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu);
1142
1143 if (!dst_check(&rt->dst, 0)) {
1144 if (new)
1145 dst_release(&rt->dst);
1146
1147 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1148 if (IS_ERR(rt))
1149 goto out;
1150
1151 new = true;
1152 }
1153
1154 if (new)
1155 sk_dst_set(sk, &rt->dst);
1156
1157out:
1158 bh_unlock_sock(sk);
1159 dst_release(odst);
1160}
1161EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1162
1163void ipv4_redirect(struct sk_buff *skb, struct net *net,
1164 int oif, u8 protocol)
1165{
1166 const struct iphdr *iph = (const struct iphdr *)skb->data;
1167 struct flowi4 fl4;
1168 struct rtable *rt;
1169
1170 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, 0, 0);
1171 rt = __ip_route_output_key(net, &fl4);
1172 if (!IS_ERR(rt)) {
1173 __ip_do_redirect(rt, skb, &fl4, false);
1174 ip_rt_put(rt);
1175 }
1176}
1177EXPORT_SYMBOL_GPL(ipv4_redirect);
1178
1179void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1180{
1181 const struct iphdr *iph = (const struct iphdr *)skb->data;
1182 struct flowi4 fl4;
1183 struct rtable *rt;
1184 struct net *net = sock_net(sk);
1185
1186 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1187 rt = __ip_route_output_key(net, &fl4);
1188 if (!IS_ERR(rt)) {
1189 __ip_do_redirect(rt, skb, &fl4, false);
1190 ip_rt_put(rt);
1191 }
1192}
1193EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1194
1195INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1196 u32 cookie)
1197{
1198 struct rtable *rt = (struct rtable *) dst;
1199
1200 /* All IPV4 dsts are created with ->obsolete set to the value
1201 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1202 * into this function always.
1203 *
1204 * When a PMTU/redirect information update invalidates a route,
1205 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1206 * DST_OBSOLETE_DEAD.
1207 */
1208 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1209 return NULL;
1210 return dst;
1211}
1212EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1213
1214static void ipv4_send_dest_unreach(struct sk_buff *skb)
1215{
1216 struct net_device *dev;
1217 struct ip_options opt;
1218 int res;
1219
1220 /* Recompile ip options since IPCB may not be valid anymore.
1221 * Also check we have a reasonable ipv4 header.
1222 */
1223 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1224 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1225 return;
1226
1227 memset(&opt, 0, sizeof(opt));
1228 if (ip_hdr(skb)->ihl > 5) {
1229 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1230 return;
1231 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1232
1233 rcu_read_lock();
1234 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
1235 res = __ip_options_compile(dev_net(dev), &opt, skb, NULL);
1236 rcu_read_unlock();
1237
1238 if (res)
1239 return;
1240 }
1241 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1242}
1243
1244static void ipv4_link_failure(struct sk_buff *skb)
1245{
1246 struct rtable *rt;
1247
1248 ipv4_send_dest_unreach(skb);
1249
1250 rt = skb_rtable(skb);
1251 if (rt)
1252 dst_set_expires(&rt->dst, 0);
1253}
1254
1255static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1256{
1257 pr_debug("%s: %pI4 -> %pI4, %s\n",
1258 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1259 skb->dev ? skb->dev->name : "?");
1260 kfree_skb(skb);
1261 WARN_ON(1);
1262 return 0;
1263}
1264
1265/*
1266 * We do not cache source address of outgoing interface,
1267 * because it is used only by IP RR, TS and SRR options,
1268 * so that it out of fast path.
1269 *
1270 * BTW remember: "addr" is allowed to be not aligned
1271 * in IP options!
1272 */
1273
1274void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1275{
1276 __be32 src;
1277
1278 if (rt_is_output_route(rt))
1279 src = ip_hdr(skb)->saddr;
1280 else {
1281 struct fib_result res;
1282 struct iphdr *iph = ip_hdr(skb);
1283 struct flowi4 fl4 = {
1284 .daddr = iph->daddr,
1285 .saddr = iph->saddr,
1286 .flowi4_tos = RT_TOS(iph->tos),
1287 .flowi4_oif = rt->dst.dev->ifindex,
1288 .flowi4_iif = skb->dev->ifindex,
1289 .flowi4_mark = skb->mark,
1290 };
1291
1292 rcu_read_lock();
1293 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1294 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1295 else
1296 src = inet_select_addr(rt->dst.dev,
1297 rt_nexthop(rt, iph->daddr),
1298 RT_SCOPE_UNIVERSE);
1299 rcu_read_unlock();
1300 }
1301 memcpy(addr, &src, 4);
1302}
1303
1304#ifdef CONFIG_IP_ROUTE_CLASSID
1305static void set_class_tag(struct rtable *rt, u32 tag)
1306{
1307 if (!(rt->dst.tclassid & 0xFFFF))
1308 rt->dst.tclassid |= tag & 0xFFFF;
1309 if (!(rt->dst.tclassid & 0xFFFF0000))
1310 rt->dst.tclassid |= tag & 0xFFFF0000;
1311}
1312#endif
1313
1314static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1315{
1316 struct net *net = dev_net(dst->dev);
1317 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1318 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1319 net->ipv4.ip_rt_min_advmss);
1320
1321 return min(advmss, IPV4_MAX_PMTU - header_size);
1322}
1323
1324INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1325{
1326 return ip_dst_mtu_maybe_forward(dst, false);
1327}
1328EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1329
1330static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1331{
1332 struct fnhe_hash_bucket *hash;
1333 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1334 u32 hval = fnhe_hashfun(daddr);
1335
1336 spin_lock_bh(&fnhe_lock);
1337
1338 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1339 lockdep_is_held(&fnhe_lock));
1340 hash += hval;
1341
1342 fnhe_p = &hash->chain;
1343 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1344 while (fnhe) {
1345 if (fnhe->fnhe_daddr == daddr) {
1346 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1347 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1348 /* set fnhe_daddr to 0 to ensure it won't bind with
1349 * new dsts in rt_bind_exception().
1350 */
1351 fnhe->fnhe_daddr = 0;
1352 fnhe_flush_routes(fnhe);
1353 kfree_rcu(fnhe, rcu);
1354 break;
1355 }
1356 fnhe_p = &fnhe->fnhe_next;
1357 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1358 lockdep_is_held(&fnhe_lock));
1359 }
1360
1361 spin_unlock_bh(&fnhe_lock);
1362}
1363
1364static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1365 __be32 daddr)
1366{
1367 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1368 struct fib_nh_exception *fnhe;
1369 u32 hval;
1370
1371 if (!hash)
1372 return NULL;
1373
1374 hval = fnhe_hashfun(daddr);
1375
1376 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1377 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1378 if (fnhe->fnhe_daddr == daddr) {
1379 if (fnhe->fnhe_expires &&
1380 time_after(jiffies, fnhe->fnhe_expires)) {
1381 ip_del_fnhe(nhc, daddr);
1382 break;
1383 }
1384 return fnhe;
1385 }
1386 }
1387 return NULL;
1388}
1389
1390/* MTU selection:
1391 * 1. mtu on route is locked - use it
1392 * 2. mtu from nexthop exception
1393 * 3. mtu from egress device
1394 */
1395
1396u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1397{
1398 struct fib_nh_common *nhc = res->nhc;
1399 struct net_device *dev = nhc->nhc_dev;
1400 struct fib_info *fi = res->fi;
1401 u32 mtu = 0;
1402
1403 if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) ||
1404 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1405 mtu = fi->fib_mtu;
1406
1407 if (likely(!mtu)) {
1408 struct fib_nh_exception *fnhe;
1409
1410 fnhe = find_exception(nhc, daddr);
1411 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1412 mtu = fnhe->fnhe_pmtu;
1413 }
1414
1415 if (likely(!mtu))
1416 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1417
1418 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1419}
1420
1421static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1422 __be32 daddr, const bool do_cache)
1423{
1424 bool ret = false;
1425
1426 spin_lock_bh(&fnhe_lock);
1427
1428 if (daddr == fnhe->fnhe_daddr) {
1429 struct rtable __rcu **porig;
1430 struct rtable *orig;
1431 int genid = fnhe_genid(dev_net(rt->dst.dev));
1432
1433 if (rt_is_input_route(rt))
1434 porig = &fnhe->fnhe_rth_input;
1435 else
1436 porig = &fnhe->fnhe_rth_output;
1437 orig = rcu_dereference(*porig);
1438
1439 if (fnhe->fnhe_genid != genid) {
1440 fnhe->fnhe_genid = genid;
1441 fnhe->fnhe_gw = 0;
1442 fnhe->fnhe_pmtu = 0;
1443 fnhe->fnhe_expires = 0;
1444 fnhe->fnhe_mtu_locked = false;
1445 fnhe_flush_routes(fnhe);
1446 orig = NULL;
1447 }
1448 fill_route_from_fnhe(rt, fnhe);
1449 if (!rt->rt_gw4) {
1450 rt->rt_gw4 = daddr;
1451 rt->rt_gw_family = AF_INET;
1452 }
1453
1454 if (do_cache) {
1455 dst_hold(&rt->dst);
1456 rcu_assign_pointer(*porig, rt);
1457 if (orig) {
1458 dst_dev_put(&orig->dst);
1459 dst_release(&orig->dst);
1460 }
1461 ret = true;
1462 }
1463
1464 fnhe->fnhe_stamp = jiffies;
1465 }
1466 spin_unlock_bh(&fnhe_lock);
1467
1468 return ret;
1469}
1470
1471static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1472{
1473 struct rtable *orig, *prev, **p;
1474 bool ret = true;
1475
1476 if (rt_is_input_route(rt)) {
1477 p = (struct rtable **)&nhc->nhc_rth_input;
1478 } else {
1479 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1480 }
1481 orig = *p;
1482
1483 /* hold dst before doing cmpxchg() to avoid race condition
1484 * on this dst
1485 */
1486 dst_hold(&rt->dst);
1487 prev = cmpxchg(p, orig, rt);
1488 if (prev == orig) {
1489 if (orig) {
1490 rt_add_uncached_list(orig);
1491 dst_release(&orig->dst);
1492 }
1493 } else {
1494 dst_release(&rt->dst);
1495 ret = false;
1496 }
1497
1498 return ret;
1499}
1500
1501struct uncached_list {
1502 spinlock_t lock;
1503 struct list_head head;
1504 struct list_head quarantine;
1505};
1506
1507static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1508
1509void rt_add_uncached_list(struct rtable *rt)
1510{
1511 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1512
1513 rt->dst.rt_uncached_list = ul;
1514
1515 spin_lock_bh(&ul->lock);
1516 list_add_tail(&rt->dst.rt_uncached, &ul->head);
1517 spin_unlock_bh(&ul->lock);
1518}
1519
1520void rt_del_uncached_list(struct rtable *rt)
1521{
1522 if (!list_empty(&rt->dst.rt_uncached)) {
1523 struct uncached_list *ul = rt->dst.rt_uncached_list;
1524
1525 spin_lock_bh(&ul->lock);
1526 list_del_init(&rt->dst.rt_uncached);
1527 spin_unlock_bh(&ul->lock);
1528 }
1529}
1530
1531static void ipv4_dst_destroy(struct dst_entry *dst)
1532{
1533 struct rtable *rt = (struct rtable *)dst;
1534
1535 ip_dst_metrics_put(dst);
1536 rt_del_uncached_list(rt);
1537}
1538
1539void rt_flush_dev(struct net_device *dev)
1540{
1541 struct rtable *rt, *safe;
1542 int cpu;
1543
1544 for_each_possible_cpu(cpu) {
1545 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1546
1547 if (list_empty(&ul->head))
1548 continue;
1549
1550 spin_lock_bh(&ul->lock);
1551 list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) {
1552 if (rt->dst.dev != dev)
1553 continue;
1554 rt->dst.dev = blackhole_netdev;
1555 netdev_ref_replace(dev, blackhole_netdev,
1556 &rt->dst.dev_tracker, GFP_ATOMIC);
1557 list_move(&rt->dst.rt_uncached, &ul->quarantine);
1558 }
1559 spin_unlock_bh(&ul->lock);
1560 }
1561}
1562
1563static bool rt_cache_valid(const struct rtable *rt)
1564{
1565 return rt &&
1566 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1567 !rt_is_expired(rt);
1568}
1569
1570static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1571 const struct fib_result *res,
1572 struct fib_nh_exception *fnhe,
1573 struct fib_info *fi, u16 type, u32 itag,
1574 const bool do_cache)
1575{
1576 bool cached = false;
1577
1578 if (fi) {
1579 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1580
1581 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1582 rt->rt_uses_gateway = 1;
1583 rt->rt_gw_family = nhc->nhc_gw_family;
1584 /* only INET and INET6 are supported */
1585 if (likely(nhc->nhc_gw_family == AF_INET))
1586 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1587 else
1588 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1589 }
1590
1591 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1592
1593#ifdef CONFIG_IP_ROUTE_CLASSID
1594 if (nhc->nhc_family == AF_INET) {
1595 struct fib_nh *nh;
1596
1597 nh = container_of(nhc, struct fib_nh, nh_common);
1598 rt->dst.tclassid = nh->nh_tclassid;
1599 }
1600#endif
1601 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1602 if (unlikely(fnhe))
1603 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1604 else if (do_cache)
1605 cached = rt_cache_route(nhc, rt);
1606 if (unlikely(!cached)) {
1607 /* Routes we intend to cache in nexthop exception or
1608 * FIB nexthop have the DST_NOCACHE bit clear.
1609 * However, if we are unsuccessful at storing this
1610 * route into the cache we really need to set it.
1611 */
1612 if (!rt->rt_gw4) {
1613 rt->rt_gw_family = AF_INET;
1614 rt->rt_gw4 = daddr;
1615 }
1616 rt_add_uncached_list(rt);
1617 }
1618 } else
1619 rt_add_uncached_list(rt);
1620
1621#ifdef CONFIG_IP_ROUTE_CLASSID
1622#ifdef CONFIG_IP_MULTIPLE_TABLES
1623 set_class_tag(rt, res->tclassid);
1624#endif
1625 set_class_tag(rt, itag);
1626#endif
1627}
1628
1629struct rtable *rt_dst_alloc(struct net_device *dev,
1630 unsigned int flags, u16 type,
1631 bool noxfrm)
1632{
1633 struct rtable *rt;
1634
1635 rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1636 (noxfrm ? DST_NOXFRM : 0));
1637
1638 if (rt) {
1639 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1640 rt->rt_flags = flags;
1641 rt->rt_type = type;
1642 rt->rt_is_input = 0;
1643 rt->rt_iif = 0;
1644 rt->rt_pmtu = 0;
1645 rt->rt_mtu_locked = 0;
1646 rt->rt_uses_gateway = 0;
1647 rt->rt_gw_family = 0;
1648 rt->rt_gw4 = 0;
1649
1650 rt->dst.output = ip_output;
1651 if (flags & RTCF_LOCAL)
1652 rt->dst.input = ip_local_deliver;
1653 }
1654
1655 return rt;
1656}
1657EXPORT_SYMBOL(rt_dst_alloc);
1658
1659struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1660{
1661 struct rtable *new_rt;
1662
1663 new_rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1664 rt->dst.flags);
1665
1666 if (new_rt) {
1667 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1668 new_rt->rt_flags = rt->rt_flags;
1669 new_rt->rt_type = rt->rt_type;
1670 new_rt->rt_is_input = rt->rt_is_input;
1671 new_rt->rt_iif = rt->rt_iif;
1672 new_rt->rt_pmtu = rt->rt_pmtu;
1673 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1674 new_rt->rt_gw_family = rt->rt_gw_family;
1675 if (rt->rt_gw_family == AF_INET)
1676 new_rt->rt_gw4 = rt->rt_gw4;
1677 else if (rt->rt_gw_family == AF_INET6)
1678 new_rt->rt_gw6 = rt->rt_gw6;
1679
1680 new_rt->dst.input = rt->dst.input;
1681 new_rt->dst.output = rt->dst.output;
1682 new_rt->dst.error = rt->dst.error;
1683 new_rt->dst.lastuse = jiffies;
1684 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1685 }
1686 return new_rt;
1687}
1688EXPORT_SYMBOL(rt_dst_clone);
1689
1690/* called in rcu_read_lock() section */
1691int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1692 u8 tos, struct net_device *dev,
1693 struct in_device *in_dev, u32 *itag)
1694{
1695 int err;
1696
1697 /* Primary sanity checks. */
1698 if (!in_dev)
1699 return -EINVAL;
1700
1701 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1702 skb->protocol != htons(ETH_P_IP))
1703 return -EINVAL;
1704
1705 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1706 return -EINVAL;
1707
1708 if (ipv4_is_zeronet(saddr)) {
1709 if (!ipv4_is_local_multicast(daddr) &&
1710 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1711 return -EINVAL;
1712 } else {
1713 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1714 in_dev, itag);
1715 if (err < 0)
1716 return err;
1717 }
1718 return 0;
1719}
1720
1721/* called in rcu_read_lock() section */
1722static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1723 u8 tos, struct net_device *dev, int our)
1724{
1725 struct in_device *in_dev = __in_dev_get_rcu(dev);
1726 unsigned int flags = RTCF_MULTICAST;
1727 struct rtable *rth;
1728 u32 itag = 0;
1729 int err;
1730
1731 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1732 if (err)
1733 return err;
1734
1735 if (our)
1736 flags |= RTCF_LOCAL;
1737
1738 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1739 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1740
1741 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1742 false);
1743 if (!rth)
1744 return -ENOBUFS;
1745
1746#ifdef CONFIG_IP_ROUTE_CLASSID
1747 rth->dst.tclassid = itag;
1748#endif
1749 rth->dst.output = ip_rt_bug;
1750 rth->rt_is_input= 1;
1751
1752#ifdef CONFIG_IP_MROUTE
1753 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1754 rth->dst.input = ip_mr_input;
1755#endif
1756 RT_CACHE_STAT_INC(in_slow_mc);
1757
1758 skb_dst_drop(skb);
1759 skb_dst_set(skb, &rth->dst);
1760 return 0;
1761}
1762
1763
1764static void ip_handle_martian_source(struct net_device *dev,
1765 struct in_device *in_dev,
1766 struct sk_buff *skb,
1767 __be32 daddr,
1768 __be32 saddr)
1769{
1770 RT_CACHE_STAT_INC(in_martian_src);
1771#ifdef CONFIG_IP_ROUTE_VERBOSE
1772 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1773 /*
1774 * RFC1812 recommendation, if source is martian,
1775 * the only hint is MAC header.
1776 */
1777 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1778 &daddr, &saddr, dev->name);
1779 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1780 print_hex_dump(KERN_WARNING, "ll header: ",
1781 DUMP_PREFIX_OFFSET, 16, 1,
1782 skb_mac_header(skb),
1783 dev->hard_header_len, false);
1784 }
1785 }
1786#endif
1787}
1788
1789/* called in rcu_read_lock() section */
1790static int __mkroute_input(struct sk_buff *skb,
1791 const struct fib_result *res,
1792 struct in_device *in_dev,
1793 __be32 daddr, __be32 saddr, u32 tos)
1794{
1795 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1796 struct net_device *dev = nhc->nhc_dev;
1797 struct fib_nh_exception *fnhe;
1798 struct rtable *rth;
1799 int err;
1800 struct in_device *out_dev;
1801 bool do_cache;
1802 u32 itag = 0;
1803
1804 /* get a working reference to the output device */
1805 out_dev = __in_dev_get_rcu(dev);
1806 if (!out_dev) {
1807 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1808 return -EINVAL;
1809 }
1810
1811 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1812 in_dev->dev, in_dev, &itag);
1813 if (err < 0) {
1814 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1815 saddr);
1816
1817 goto cleanup;
1818 }
1819
1820 do_cache = res->fi && !itag;
1821 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1822 skb->protocol == htons(ETH_P_IP)) {
1823 __be32 gw;
1824
1825 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1826 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1827 inet_addr_onlink(out_dev, saddr, gw))
1828 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1829 }
1830
1831 if (skb->protocol != htons(ETH_P_IP)) {
1832 /* Not IP (i.e. ARP). Do not create route, if it is
1833 * invalid for proxy arp. DNAT routes are always valid.
1834 *
1835 * Proxy arp feature have been extended to allow, ARP
1836 * replies back to the same interface, to support
1837 * Private VLAN switch technologies. See arp.c.
1838 */
1839 if (out_dev == in_dev &&
1840 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1841 err = -EINVAL;
1842 goto cleanup;
1843 }
1844 }
1845
1846 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1847 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1848
1849 fnhe = find_exception(nhc, daddr);
1850 if (do_cache) {
1851 if (fnhe)
1852 rth = rcu_dereference(fnhe->fnhe_rth_input);
1853 else
1854 rth = rcu_dereference(nhc->nhc_rth_input);
1855 if (rt_cache_valid(rth)) {
1856 skb_dst_set_noref(skb, &rth->dst);
1857 goto out;
1858 }
1859 }
1860
1861 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1862 IN_DEV_ORCONF(out_dev, NOXFRM));
1863 if (!rth) {
1864 err = -ENOBUFS;
1865 goto cleanup;
1866 }
1867
1868 rth->rt_is_input = 1;
1869 RT_CACHE_STAT_INC(in_slow_tot);
1870
1871 rth->dst.input = ip_forward;
1872
1873 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1874 do_cache);
1875 lwtunnel_set_redirect(&rth->dst);
1876 skb_dst_set(skb, &rth->dst);
1877out:
1878 err = 0;
1879 cleanup:
1880 return err;
1881}
1882
1883#ifdef CONFIG_IP_ROUTE_MULTIPATH
1884/* To make ICMP packets follow the right flow, the multipath hash is
1885 * calculated from the inner IP addresses.
1886 */
1887static void ip_multipath_l3_keys(const struct sk_buff *skb,
1888 struct flow_keys *hash_keys)
1889{
1890 const struct iphdr *outer_iph = ip_hdr(skb);
1891 const struct iphdr *key_iph = outer_iph;
1892 const struct iphdr *inner_iph;
1893 const struct icmphdr *icmph;
1894 struct iphdr _inner_iph;
1895 struct icmphdr _icmph;
1896
1897 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1898 goto out;
1899
1900 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1901 goto out;
1902
1903 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1904 &_icmph);
1905 if (!icmph)
1906 goto out;
1907
1908 if (!icmp_is_err(icmph->type))
1909 goto out;
1910
1911 inner_iph = skb_header_pointer(skb,
1912 outer_iph->ihl * 4 + sizeof(_icmph),
1913 sizeof(_inner_iph), &_inner_iph);
1914 if (!inner_iph)
1915 goto out;
1916
1917 key_iph = inner_iph;
1918out:
1919 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1920 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1921}
1922
1923static u32 fib_multipath_custom_hash_outer(const struct net *net,
1924 const struct sk_buff *skb,
1925 bool *p_has_inner)
1926{
1927 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1928 struct flow_keys keys, hash_keys;
1929
1930 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1931 return 0;
1932
1933 memset(&hash_keys, 0, sizeof(hash_keys));
1934 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1935
1936 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1937 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1938 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1939 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1940 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1941 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1942 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1943 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1944 hash_keys.ports.src = keys.ports.src;
1945 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1946 hash_keys.ports.dst = keys.ports.dst;
1947
1948 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1949 return flow_hash_from_keys(&hash_keys);
1950}
1951
1952static u32 fib_multipath_custom_hash_inner(const struct net *net,
1953 const struct sk_buff *skb,
1954 bool has_inner)
1955{
1956 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1957 struct flow_keys keys, hash_keys;
1958
1959 /* We assume the packet carries an encapsulation, but if none was
1960 * encountered during dissection of the outer flow, then there is no
1961 * point in calling the flow dissector again.
1962 */
1963 if (!has_inner)
1964 return 0;
1965
1966 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1967 return 0;
1968
1969 memset(&hash_keys, 0, sizeof(hash_keys));
1970 skb_flow_dissect_flow_keys(skb, &keys, 0);
1971
1972 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1973 return 0;
1974
1975 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1976 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1977 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1978 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1979 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1980 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1981 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1982 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1983 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1984 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1985 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1986 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1987 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1988 hash_keys.tags.flow_label = keys.tags.flow_label;
1989 }
1990
1991 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
1992 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1993 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
1994 hash_keys.ports.src = keys.ports.src;
1995 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
1996 hash_keys.ports.dst = keys.ports.dst;
1997
1998 return flow_hash_from_keys(&hash_keys);
1999}
2000
2001static u32 fib_multipath_custom_hash_skb(const struct net *net,
2002 const struct sk_buff *skb)
2003{
2004 u32 mhash, mhash_inner;
2005 bool has_inner = true;
2006
2007 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
2008 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
2009
2010 return jhash_2words(mhash, mhash_inner, 0);
2011}
2012
2013static u32 fib_multipath_custom_hash_fl4(const struct net *net,
2014 const struct flowi4 *fl4)
2015{
2016 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
2017 struct flow_keys hash_keys;
2018
2019 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
2020 return 0;
2021
2022 memset(&hash_keys, 0, sizeof(hash_keys));
2023 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2024 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2025 hash_keys.addrs.v4addrs.src = fl4->saddr;
2026 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2027 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2028 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2029 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2030 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2031 hash_keys.ports.src = fl4->fl4_sport;
2032 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2033 hash_keys.ports.dst = fl4->fl4_dport;
2034
2035 return flow_hash_from_keys(&hash_keys);
2036}
2037
2038/* if skb is set it will be used and fl4 can be NULL */
2039int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2040 const struct sk_buff *skb, struct flow_keys *flkeys)
2041{
2042 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2043 struct flow_keys hash_keys;
2044 u32 mhash = 0;
2045
2046 switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
2047 case 0:
2048 memset(&hash_keys, 0, sizeof(hash_keys));
2049 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2050 if (skb) {
2051 ip_multipath_l3_keys(skb, &hash_keys);
2052 } else {
2053 hash_keys.addrs.v4addrs.src = fl4->saddr;
2054 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2055 }
2056 mhash = flow_hash_from_keys(&hash_keys);
2057 break;
2058 case 1:
2059 /* skb is currently provided only when forwarding */
2060 if (skb) {
2061 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2062 struct flow_keys keys;
2063
2064 /* short-circuit if we already have L4 hash present */
2065 if (skb->l4_hash)
2066 return skb_get_hash_raw(skb) >> 1;
2067
2068 memset(&hash_keys, 0, sizeof(hash_keys));
2069
2070 if (!flkeys) {
2071 skb_flow_dissect_flow_keys(skb, &keys, flag);
2072 flkeys = &keys;
2073 }
2074
2075 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2076 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2077 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2078 hash_keys.ports.src = flkeys->ports.src;
2079 hash_keys.ports.dst = flkeys->ports.dst;
2080 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2081 } else {
2082 memset(&hash_keys, 0, sizeof(hash_keys));
2083 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2084 hash_keys.addrs.v4addrs.src = fl4->saddr;
2085 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2086 hash_keys.ports.src = fl4->fl4_sport;
2087 hash_keys.ports.dst = fl4->fl4_dport;
2088 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2089 }
2090 mhash = flow_hash_from_keys(&hash_keys);
2091 break;
2092 case 2:
2093 memset(&hash_keys, 0, sizeof(hash_keys));
2094 /* skb is currently provided only when forwarding */
2095 if (skb) {
2096 struct flow_keys keys;
2097
2098 skb_flow_dissect_flow_keys(skb, &keys, 0);
2099 /* Inner can be v4 or v6 */
2100 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2101 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2102 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2103 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2104 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2105 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2106 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2107 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2108 hash_keys.tags.flow_label = keys.tags.flow_label;
2109 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2110 } else {
2111 /* Same as case 0 */
2112 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2113 ip_multipath_l3_keys(skb, &hash_keys);
2114 }
2115 } else {
2116 /* Same as case 0 */
2117 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2118 hash_keys.addrs.v4addrs.src = fl4->saddr;
2119 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2120 }
2121 mhash = flow_hash_from_keys(&hash_keys);
2122 break;
2123 case 3:
2124 if (skb)
2125 mhash = fib_multipath_custom_hash_skb(net, skb);
2126 else
2127 mhash = fib_multipath_custom_hash_fl4(net, fl4);
2128 break;
2129 }
2130
2131 if (multipath_hash)
2132 mhash = jhash_2words(mhash, multipath_hash, 0);
2133
2134 return mhash >> 1;
2135}
2136#endif /* CONFIG_IP_ROUTE_MULTIPATH */
2137
2138static int ip_mkroute_input(struct sk_buff *skb,
2139 struct fib_result *res,
2140 struct in_device *in_dev,
2141 __be32 daddr, __be32 saddr, u32 tos,
2142 struct flow_keys *hkeys)
2143{
2144#ifdef CONFIG_IP_ROUTE_MULTIPATH
2145 if (res->fi && fib_info_num_path(res->fi) > 1) {
2146 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2147
2148 fib_select_multipath(res, h);
2149 IPCB(skb)->flags |= IPSKB_MULTIPATH;
2150 }
2151#endif
2152
2153 /* create a routing cache entry */
2154 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2155}
2156
2157/* Implements all the saddr-related checks as ip_route_input_slow(),
2158 * assuming daddr is valid and the destination is not a local broadcast one.
2159 * Uses the provided hint instead of performing a route lookup.
2160 */
2161int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2162 u8 tos, struct net_device *dev,
2163 const struct sk_buff *hint)
2164{
2165 struct in_device *in_dev = __in_dev_get_rcu(dev);
2166 struct rtable *rt = skb_rtable(hint);
2167 struct net *net = dev_net(dev);
2168 int err = -EINVAL;
2169 u32 tag = 0;
2170
2171 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2172 goto martian_source;
2173
2174 if (ipv4_is_zeronet(saddr))
2175 goto martian_source;
2176
2177 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2178 goto martian_source;
2179
2180 if (rt->rt_type != RTN_LOCAL)
2181 goto skip_validate_source;
2182
2183 tos &= IPTOS_RT_MASK;
2184 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2185 if (err < 0)
2186 goto martian_source;
2187
2188skip_validate_source:
2189 skb_dst_copy(skb, hint);
2190 return 0;
2191
2192martian_source:
2193 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2194 return err;
2195}
2196
2197/* get device for dst_alloc with local routes */
2198static struct net_device *ip_rt_get_dev(struct net *net,
2199 const struct fib_result *res)
2200{
2201 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2202 struct net_device *dev = NULL;
2203
2204 if (nhc)
2205 dev = l3mdev_master_dev_rcu(nhc->nhc_dev);
2206
2207 return dev ? : net->loopback_dev;
2208}
2209
2210/*
2211 * NOTE. We drop all the packets that has local source
2212 * addresses, because every properly looped back packet
2213 * must have correct destination already attached by output routine.
2214 * Changes in the enforced policies must be applied also to
2215 * ip_route_use_hint().
2216 *
2217 * Such approach solves two big problems:
2218 * 1. Not simplex devices are handled properly.
2219 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2220 * called with rcu_read_lock()
2221 */
2222
2223static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2224 u8 tos, struct net_device *dev,
2225 struct fib_result *res)
2226{
2227 struct in_device *in_dev = __in_dev_get_rcu(dev);
2228 struct flow_keys *flkeys = NULL, _flkeys;
2229 struct net *net = dev_net(dev);
2230 struct ip_tunnel_info *tun_info;
2231 int err = -EINVAL;
2232 unsigned int flags = 0;
2233 u32 itag = 0;
2234 struct rtable *rth;
2235 struct flowi4 fl4;
2236 bool do_cache = true;
2237
2238 /* IP on this device is disabled. */
2239
2240 if (!in_dev)
2241 goto out;
2242
2243 /* Check for the most weird martians, which can be not detected
2244 * by fib_lookup.
2245 */
2246
2247 tun_info = skb_tunnel_info(skb);
2248 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2249 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2250 else
2251 fl4.flowi4_tun_key.tun_id = 0;
2252 skb_dst_drop(skb);
2253
2254 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2255 goto martian_source;
2256
2257 res->fi = NULL;
2258 res->table = NULL;
2259 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2260 goto brd_input;
2261
2262 /* Accept zero addresses only to limited broadcast;
2263 * I even do not know to fix it or not. Waiting for complains :-)
2264 */
2265 if (ipv4_is_zeronet(saddr))
2266 goto martian_source;
2267
2268 if (ipv4_is_zeronet(daddr))
2269 goto martian_destination;
2270
2271 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2272 * and call it once if daddr or/and saddr are loopback addresses
2273 */
2274 if (ipv4_is_loopback(daddr)) {
2275 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2276 goto martian_destination;
2277 } else if (ipv4_is_loopback(saddr)) {
2278 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2279 goto martian_source;
2280 }
2281
2282 /*
2283 * Now we are ready to route packet.
2284 */
2285 fl4.flowi4_l3mdev = 0;
2286 fl4.flowi4_oif = 0;
2287 fl4.flowi4_iif = dev->ifindex;
2288 fl4.flowi4_mark = skb->mark;
2289 fl4.flowi4_tos = tos;
2290 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2291 fl4.flowi4_flags = 0;
2292 fl4.daddr = daddr;
2293 fl4.saddr = saddr;
2294 fl4.flowi4_uid = sock_net_uid(net, NULL);
2295 fl4.flowi4_multipath_hash = 0;
2296
2297 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2298 flkeys = &_flkeys;
2299 } else {
2300 fl4.flowi4_proto = 0;
2301 fl4.fl4_sport = 0;
2302 fl4.fl4_dport = 0;
2303 }
2304
2305 err = fib_lookup(net, &fl4, res, 0);
2306 if (err != 0) {
2307 if (!IN_DEV_FORWARD(in_dev))
2308 err = -EHOSTUNREACH;
2309 goto no_route;
2310 }
2311
2312 if (res->type == RTN_BROADCAST) {
2313 if (IN_DEV_BFORWARD(in_dev))
2314 goto make_route;
2315 /* not do cache if bc_forwarding is enabled */
2316 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))
2317 do_cache = false;
2318 goto brd_input;
2319 }
2320
2321 if (res->type == RTN_LOCAL) {
2322 err = fib_validate_source(skb, saddr, daddr, tos,
2323 0, dev, in_dev, &itag);
2324 if (err < 0)
2325 goto martian_source;
2326 goto local_input;
2327 }
2328
2329 if (!IN_DEV_FORWARD(in_dev)) {
2330 err = -EHOSTUNREACH;
2331 goto no_route;
2332 }
2333 if (res->type != RTN_UNICAST)
2334 goto martian_destination;
2335
2336make_route:
2337 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2338out: return err;
2339
2340brd_input:
2341 if (skb->protocol != htons(ETH_P_IP))
2342 goto e_inval;
2343
2344 if (!ipv4_is_zeronet(saddr)) {
2345 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2346 in_dev, &itag);
2347 if (err < 0)
2348 goto martian_source;
2349 }
2350 flags |= RTCF_BROADCAST;
2351 res->type = RTN_BROADCAST;
2352 RT_CACHE_STAT_INC(in_brd);
2353
2354local_input:
2355 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
2356 IPCB(skb)->flags |= IPSKB_NOPOLICY;
2357
2358 do_cache &= res->fi && !itag;
2359 if (do_cache) {
2360 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2361
2362 rth = rcu_dereference(nhc->nhc_rth_input);
2363 if (rt_cache_valid(rth)) {
2364 skb_dst_set_noref(skb, &rth->dst);
2365 err = 0;
2366 goto out;
2367 }
2368 }
2369
2370 rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2371 flags | RTCF_LOCAL, res->type, false);
2372 if (!rth)
2373 goto e_nobufs;
2374
2375 rth->dst.output= ip_rt_bug;
2376#ifdef CONFIG_IP_ROUTE_CLASSID
2377 rth->dst.tclassid = itag;
2378#endif
2379 rth->rt_is_input = 1;
2380
2381 RT_CACHE_STAT_INC(in_slow_tot);
2382 if (res->type == RTN_UNREACHABLE) {
2383 rth->dst.input= ip_error;
2384 rth->dst.error= -err;
2385 rth->rt_flags &= ~RTCF_LOCAL;
2386 }
2387
2388 if (do_cache) {
2389 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2390
2391 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2392 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2393 WARN_ON(rth->dst.input == lwtunnel_input);
2394 rth->dst.lwtstate->orig_input = rth->dst.input;
2395 rth->dst.input = lwtunnel_input;
2396 }
2397
2398 if (unlikely(!rt_cache_route(nhc, rth)))
2399 rt_add_uncached_list(rth);
2400 }
2401 skb_dst_set(skb, &rth->dst);
2402 err = 0;
2403 goto out;
2404
2405no_route:
2406 RT_CACHE_STAT_INC(in_no_route);
2407 res->type = RTN_UNREACHABLE;
2408 res->fi = NULL;
2409 res->table = NULL;
2410 goto local_input;
2411
2412 /*
2413 * Do not cache martian addresses: they should be logged (RFC1812)
2414 */
2415martian_destination:
2416 RT_CACHE_STAT_INC(in_martian_dst);
2417#ifdef CONFIG_IP_ROUTE_VERBOSE
2418 if (IN_DEV_LOG_MARTIANS(in_dev))
2419 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2420 &daddr, &saddr, dev->name);
2421#endif
2422
2423e_inval:
2424 err = -EINVAL;
2425 goto out;
2426
2427e_nobufs:
2428 err = -ENOBUFS;
2429 goto out;
2430
2431martian_source:
2432 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2433 goto out;
2434}
2435
2436/* called with rcu_read_lock held */
2437static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2438 u8 tos, struct net_device *dev, struct fib_result *res)
2439{
2440 /* Multicast recognition logic is moved from route cache to here.
2441 * The problem was that too many Ethernet cards have broken/missing
2442 * hardware multicast filters :-( As result the host on multicasting
2443 * network acquires a lot of useless route cache entries, sort of
2444 * SDR messages from all the world. Now we try to get rid of them.
2445 * Really, provided software IP multicast filter is organized
2446 * reasonably (at least, hashed), it does not result in a slowdown
2447 * comparing with route cache reject entries.
2448 * Note, that multicast routers are not affected, because
2449 * route cache entry is created eventually.
2450 */
2451 if (ipv4_is_multicast(daddr)) {
2452 struct in_device *in_dev = __in_dev_get_rcu(dev);
2453 int our = 0;
2454 int err = -EINVAL;
2455
2456 if (!in_dev)
2457 return err;
2458 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2459 ip_hdr(skb)->protocol);
2460
2461 /* check l3 master if no match yet */
2462 if (!our && netif_is_l3_slave(dev)) {
2463 struct in_device *l3_in_dev;
2464
2465 l3_in_dev = __in_dev_get_rcu(skb->dev);
2466 if (l3_in_dev)
2467 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2468 ip_hdr(skb)->protocol);
2469 }
2470
2471 if (our
2472#ifdef CONFIG_IP_MROUTE
2473 ||
2474 (!ipv4_is_local_multicast(daddr) &&
2475 IN_DEV_MFORWARD(in_dev))
2476#endif
2477 ) {
2478 err = ip_route_input_mc(skb, daddr, saddr,
2479 tos, dev, our);
2480 }
2481 return err;
2482 }
2483
2484 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2485}
2486
2487int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2488 u8 tos, struct net_device *dev)
2489{
2490 struct fib_result res;
2491 int err;
2492
2493 tos &= IPTOS_RT_MASK;
2494 rcu_read_lock();
2495 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2496 rcu_read_unlock();
2497
2498 return err;
2499}
2500EXPORT_SYMBOL(ip_route_input_noref);
2501
2502/* called with rcu_read_lock() */
2503static struct rtable *__mkroute_output(const struct fib_result *res,
2504 const struct flowi4 *fl4, int orig_oif,
2505 struct net_device *dev_out,
2506 unsigned int flags)
2507{
2508 struct fib_info *fi = res->fi;
2509 struct fib_nh_exception *fnhe;
2510 struct in_device *in_dev;
2511 u16 type = res->type;
2512 struct rtable *rth;
2513 bool do_cache;
2514
2515 in_dev = __in_dev_get_rcu(dev_out);
2516 if (!in_dev)
2517 return ERR_PTR(-EINVAL);
2518
2519 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2520 if (ipv4_is_loopback(fl4->saddr) &&
2521 !(dev_out->flags & IFF_LOOPBACK) &&
2522 !netif_is_l3_master(dev_out))
2523 return ERR_PTR(-EINVAL);
2524
2525 if (ipv4_is_lbcast(fl4->daddr))
2526 type = RTN_BROADCAST;
2527 else if (ipv4_is_multicast(fl4->daddr))
2528 type = RTN_MULTICAST;
2529 else if (ipv4_is_zeronet(fl4->daddr))
2530 return ERR_PTR(-EINVAL);
2531
2532 if (dev_out->flags & IFF_LOOPBACK)
2533 flags |= RTCF_LOCAL;
2534
2535 do_cache = true;
2536 if (type == RTN_BROADCAST) {
2537 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2538 fi = NULL;
2539 } else if (type == RTN_MULTICAST) {
2540 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2541 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2542 fl4->flowi4_proto))
2543 flags &= ~RTCF_LOCAL;
2544 else
2545 do_cache = false;
2546 /* If multicast route do not exist use
2547 * default one, but do not gateway in this case.
2548 * Yes, it is hack.
2549 */
2550 if (fi && res->prefixlen < 4)
2551 fi = NULL;
2552 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2553 (orig_oif != dev_out->ifindex)) {
2554 /* For local routes that require a particular output interface
2555 * we do not want to cache the result. Caching the result
2556 * causes incorrect behaviour when there are multiple source
2557 * addresses on the interface, the end result being that if the
2558 * intended recipient is waiting on that interface for the
2559 * packet he won't receive it because it will be delivered on
2560 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2561 * be set to the loopback interface as well.
2562 */
2563 do_cache = false;
2564 }
2565
2566 fnhe = NULL;
2567 do_cache &= fi != NULL;
2568 if (fi) {
2569 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2570 struct rtable __rcu **prth;
2571
2572 fnhe = find_exception(nhc, fl4->daddr);
2573 if (!do_cache)
2574 goto add;
2575 if (fnhe) {
2576 prth = &fnhe->fnhe_rth_output;
2577 } else {
2578 if (unlikely(fl4->flowi4_flags &
2579 FLOWI_FLAG_KNOWN_NH &&
2580 !(nhc->nhc_gw_family &&
2581 nhc->nhc_scope == RT_SCOPE_LINK))) {
2582 do_cache = false;
2583 goto add;
2584 }
2585 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2586 }
2587 rth = rcu_dereference(*prth);
2588 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2589 return rth;
2590 }
2591
2592add:
2593 rth = rt_dst_alloc(dev_out, flags, type,
2594 IN_DEV_ORCONF(in_dev, NOXFRM));
2595 if (!rth)
2596 return ERR_PTR(-ENOBUFS);
2597
2598 rth->rt_iif = orig_oif;
2599
2600 RT_CACHE_STAT_INC(out_slow_tot);
2601
2602 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2603 if (flags & RTCF_LOCAL &&
2604 !(dev_out->flags & IFF_LOOPBACK)) {
2605 rth->dst.output = ip_mc_output;
2606 RT_CACHE_STAT_INC(out_slow_mc);
2607 }
2608#ifdef CONFIG_IP_MROUTE
2609 if (type == RTN_MULTICAST) {
2610 if (IN_DEV_MFORWARD(in_dev) &&
2611 !ipv4_is_local_multicast(fl4->daddr)) {
2612 rth->dst.input = ip_mr_input;
2613 rth->dst.output = ip_mc_output;
2614 }
2615 }
2616#endif
2617 }
2618
2619 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2620 lwtunnel_set_redirect(&rth->dst);
2621
2622 return rth;
2623}
2624
2625/*
2626 * Major route resolver routine.
2627 */
2628
2629struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2630 const struct sk_buff *skb)
2631{
2632 struct fib_result res = {
2633 .type = RTN_UNSPEC,
2634 .fi = NULL,
2635 .table = NULL,
2636 .tclassid = 0,
2637 };
2638 struct rtable *rth;
2639
2640 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2641 ip_rt_fix_tos(fl4);
2642
2643 rcu_read_lock();
2644 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2645 rcu_read_unlock();
2646
2647 return rth;
2648}
2649EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2650
2651struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2652 struct fib_result *res,
2653 const struct sk_buff *skb)
2654{
2655 struct net_device *dev_out = NULL;
2656 int orig_oif = fl4->flowi4_oif;
2657 unsigned int flags = 0;
2658 struct rtable *rth;
2659 int err;
2660
2661 if (fl4->saddr) {
2662 if (ipv4_is_multicast(fl4->saddr) ||
2663 ipv4_is_lbcast(fl4->saddr) ||
2664 ipv4_is_zeronet(fl4->saddr)) {
2665 rth = ERR_PTR(-EINVAL);
2666 goto out;
2667 }
2668
2669 rth = ERR_PTR(-ENETUNREACH);
2670
2671 /* I removed check for oif == dev_out->oif here.
2672 * It was wrong for two reasons:
2673 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2674 * is assigned to multiple interfaces.
2675 * 2. Moreover, we are allowed to send packets with saddr
2676 * of another iface. --ANK
2677 */
2678
2679 if (fl4->flowi4_oif == 0 &&
2680 (ipv4_is_multicast(fl4->daddr) ||
2681 ipv4_is_lbcast(fl4->daddr))) {
2682 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2683 dev_out = __ip_dev_find(net, fl4->saddr, false);
2684 if (!dev_out)
2685 goto out;
2686
2687 /* Special hack: user can direct multicasts
2688 * and limited broadcast via necessary interface
2689 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2690 * This hack is not just for fun, it allows
2691 * vic,vat and friends to work.
2692 * They bind socket to loopback, set ttl to zero
2693 * and expect that it will work.
2694 * From the viewpoint of routing cache they are broken,
2695 * because we are not allowed to build multicast path
2696 * with loopback source addr (look, routing cache
2697 * cannot know, that ttl is zero, so that packet
2698 * will not leave this host and route is valid).
2699 * Luckily, this hack is good workaround.
2700 */
2701
2702 fl4->flowi4_oif = dev_out->ifindex;
2703 goto make_route;
2704 }
2705
2706 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2707 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2708 if (!__ip_dev_find(net, fl4->saddr, false))
2709 goto out;
2710 }
2711 }
2712
2713
2714 if (fl4->flowi4_oif) {
2715 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2716 rth = ERR_PTR(-ENODEV);
2717 if (!dev_out)
2718 goto out;
2719
2720 /* RACE: Check return value of inet_select_addr instead. */
2721 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2722 rth = ERR_PTR(-ENETUNREACH);
2723 goto out;
2724 }
2725 if (ipv4_is_local_multicast(fl4->daddr) ||
2726 ipv4_is_lbcast(fl4->daddr) ||
2727 fl4->flowi4_proto == IPPROTO_IGMP) {
2728 if (!fl4->saddr)
2729 fl4->saddr = inet_select_addr(dev_out, 0,
2730 RT_SCOPE_LINK);
2731 goto make_route;
2732 }
2733 if (!fl4->saddr) {
2734 if (ipv4_is_multicast(fl4->daddr))
2735 fl4->saddr = inet_select_addr(dev_out, 0,
2736 fl4->flowi4_scope);
2737 else if (!fl4->daddr)
2738 fl4->saddr = inet_select_addr(dev_out, 0,
2739 RT_SCOPE_HOST);
2740 }
2741 }
2742
2743 if (!fl4->daddr) {
2744 fl4->daddr = fl4->saddr;
2745 if (!fl4->daddr)
2746 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2747 dev_out = net->loopback_dev;
2748 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2749 res->type = RTN_LOCAL;
2750 flags |= RTCF_LOCAL;
2751 goto make_route;
2752 }
2753
2754 err = fib_lookup(net, fl4, res, 0);
2755 if (err) {
2756 res->fi = NULL;
2757 res->table = NULL;
2758 if (fl4->flowi4_oif &&
2759 (ipv4_is_multicast(fl4->daddr) || !fl4->flowi4_l3mdev)) {
2760 /* Apparently, routing tables are wrong. Assume,
2761 * that the destination is on link.
2762 *
2763 * WHY? DW.
2764 * Because we are allowed to send to iface
2765 * even if it has NO routes and NO assigned
2766 * addresses. When oif is specified, routing
2767 * tables are looked up with only one purpose:
2768 * to catch if destination is gatewayed, rather than
2769 * direct. Moreover, if MSG_DONTROUTE is set,
2770 * we send packet, ignoring both routing tables
2771 * and ifaddr state. --ANK
2772 *
2773 *
2774 * We could make it even if oif is unknown,
2775 * likely IPv6, but we do not.
2776 */
2777
2778 if (fl4->saddr == 0)
2779 fl4->saddr = inet_select_addr(dev_out, 0,
2780 RT_SCOPE_LINK);
2781 res->type = RTN_UNICAST;
2782 goto make_route;
2783 }
2784 rth = ERR_PTR(err);
2785 goto out;
2786 }
2787
2788 if (res->type == RTN_LOCAL) {
2789 if (!fl4->saddr) {
2790 if (res->fi->fib_prefsrc)
2791 fl4->saddr = res->fi->fib_prefsrc;
2792 else
2793 fl4->saddr = fl4->daddr;
2794 }
2795
2796 /* L3 master device is the loopback for that domain */
2797 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2798 net->loopback_dev;
2799
2800 /* make sure orig_oif points to fib result device even
2801 * though packet rx/tx happens over loopback or l3mdev
2802 */
2803 orig_oif = FIB_RES_OIF(*res);
2804
2805 fl4->flowi4_oif = dev_out->ifindex;
2806 flags |= RTCF_LOCAL;
2807 goto make_route;
2808 }
2809
2810 fib_select_path(net, res, fl4, skb);
2811
2812 dev_out = FIB_RES_DEV(*res);
2813
2814make_route:
2815 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2816
2817out:
2818 return rth;
2819}
2820
2821static struct dst_ops ipv4_dst_blackhole_ops = {
2822 .family = AF_INET,
2823 .default_advmss = ipv4_default_advmss,
2824 .neigh_lookup = ipv4_neigh_lookup,
2825 .check = dst_blackhole_check,
2826 .cow_metrics = dst_blackhole_cow_metrics,
2827 .update_pmtu = dst_blackhole_update_pmtu,
2828 .redirect = dst_blackhole_redirect,
2829 .mtu = dst_blackhole_mtu,
2830};
2831
2832struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2833{
2834 struct rtable *ort = (struct rtable *) dst_orig;
2835 struct rtable *rt;
2836
2837 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, 0);
2838 if (rt) {
2839 struct dst_entry *new = &rt->dst;
2840
2841 new->__use = 1;
2842 new->input = dst_discard;
2843 new->output = dst_discard_out;
2844
2845 new->dev = net->loopback_dev;
2846 netdev_hold(new->dev, &new->dev_tracker, GFP_ATOMIC);
2847
2848 rt->rt_is_input = ort->rt_is_input;
2849 rt->rt_iif = ort->rt_iif;
2850 rt->rt_pmtu = ort->rt_pmtu;
2851 rt->rt_mtu_locked = ort->rt_mtu_locked;
2852
2853 rt->rt_genid = rt_genid_ipv4(net);
2854 rt->rt_flags = ort->rt_flags;
2855 rt->rt_type = ort->rt_type;
2856 rt->rt_uses_gateway = ort->rt_uses_gateway;
2857 rt->rt_gw_family = ort->rt_gw_family;
2858 if (rt->rt_gw_family == AF_INET)
2859 rt->rt_gw4 = ort->rt_gw4;
2860 else if (rt->rt_gw_family == AF_INET6)
2861 rt->rt_gw6 = ort->rt_gw6;
2862 }
2863
2864 dst_release(dst_orig);
2865
2866 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2867}
2868
2869struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2870 const struct sock *sk)
2871{
2872 struct rtable *rt = __ip_route_output_key(net, flp4);
2873
2874 if (IS_ERR(rt))
2875 return rt;
2876
2877 if (flp4->flowi4_proto) {
2878 flp4->flowi4_oif = rt->dst.dev->ifindex;
2879 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2880 flowi4_to_flowi(flp4),
2881 sk, 0);
2882 }
2883
2884 return rt;
2885}
2886EXPORT_SYMBOL_GPL(ip_route_output_flow);
2887
2888/* called with rcu_read_lock held */
2889static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2890 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2891 struct sk_buff *skb, u32 portid, u32 seq,
2892 unsigned int flags)
2893{
2894 struct rtmsg *r;
2895 struct nlmsghdr *nlh;
2896 unsigned long expires = 0;
2897 u32 error;
2898 u32 metrics[RTAX_MAX];
2899
2900 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2901 if (!nlh)
2902 return -EMSGSIZE;
2903
2904 r = nlmsg_data(nlh);
2905 r->rtm_family = AF_INET;
2906 r->rtm_dst_len = 32;
2907 r->rtm_src_len = 0;
2908 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2909 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2910 if (nla_put_u32(skb, RTA_TABLE, table_id))
2911 goto nla_put_failure;
2912 r->rtm_type = rt->rt_type;
2913 r->rtm_scope = RT_SCOPE_UNIVERSE;
2914 r->rtm_protocol = RTPROT_UNSPEC;
2915 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2916 if (rt->rt_flags & RTCF_NOTIFY)
2917 r->rtm_flags |= RTM_F_NOTIFY;
2918 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2919 r->rtm_flags |= RTCF_DOREDIRECT;
2920
2921 if (nla_put_in_addr(skb, RTA_DST, dst))
2922 goto nla_put_failure;
2923 if (src) {
2924 r->rtm_src_len = 32;
2925 if (nla_put_in_addr(skb, RTA_SRC, src))
2926 goto nla_put_failure;
2927 }
2928 if (rt->dst.dev &&
2929 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2930 goto nla_put_failure;
2931 if (rt->dst.lwtstate &&
2932 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
2933 goto nla_put_failure;
2934#ifdef CONFIG_IP_ROUTE_CLASSID
2935 if (rt->dst.tclassid &&
2936 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2937 goto nla_put_failure;
2938#endif
2939 if (fl4 && !rt_is_input_route(rt) &&
2940 fl4->saddr != src) {
2941 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2942 goto nla_put_failure;
2943 }
2944 if (rt->rt_uses_gateway) {
2945 if (rt->rt_gw_family == AF_INET &&
2946 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2947 goto nla_put_failure;
2948 } else if (rt->rt_gw_family == AF_INET6) {
2949 int alen = sizeof(struct in6_addr);
2950 struct nlattr *nla;
2951 struct rtvia *via;
2952
2953 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2954 if (!nla)
2955 goto nla_put_failure;
2956
2957 via = nla_data(nla);
2958 via->rtvia_family = AF_INET6;
2959 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2960 }
2961 }
2962
2963 expires = rt->dst.expires;
2964 if (expires) {
2965 unsigned long now = jiffies;
2966
2967 if (time_before(now, expires))
2968 expires -= now;
2969 else
2970 expires = 0;
2971 }
2972
2973 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2974 if (rt->rt_pmtu && expires)
2975 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2976 if (rt->rt_mtu_locked && expires)
2977 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2978 if (rtnetlink_put_metrics(skb, metrics) < 0)
2979 goto nla_put_failure;
2980
2981 if (fl4) {
2982 if (fl4->flowi4_mark &&
2983 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2984 goto nla_put_failure;
2985
2986 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2987 nla_put_u32(skb, RTA_UID,
2988 from_kuid_munged(current_user_ns(),
2989 fl4->flowi4_uid)))
2990 goto nla_put_failure;
2991
2992 if (rt_is_input_route(rt)) {
2993#ifdef CONFIG_IP_MROUTE
2994 if (ipv4_is_multicast(dst) &&
2995 !ipv4_is_local_multicast(dst) &&
2996 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2997 int err = ipmr_get_route(net, skb,
2998 fl4->saddr, fl4->daddr,
2999 r, portid);
3000
3001 if (err <= 0) {
3002 if (err == 0)
3003 return 0;
3004 goto nla_put_failure;
3005 }
3006 } else
3007#endif
3008 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
3009 goto nla_put_failure;
3010 }
3011 }
3012
3013 error = rt->dst.error;
3014
3015 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
3016 goto nla_put_failure;
3017
3018 nlmsg_end(skb, nlh);
3019 return 0;
3020
3021nla_put_failure:
3022 nlmsg_cancel(skb, nlh);
3023 return -EMSGSIZE;
3024}
3025
3026static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3027 struct netlink_callback *cb, u32 table_id,
3028 struct fnhe_hash_bucket *bucket, int genid,
3029 int *fa_index, int fa_start, unsigned int flags)
3030{
3031 int i;
3032
3033 for (i = 0; i < FNHE_HASH_SIZE; i++) {
3034 struct fib_nh_exception *fnhe;
3035
3036 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3037 fnhe = rcu_dereference(fnhe->fnhe_next)) {
3038 struct rtable *rt;
3039 int err;
3040
3041 if (*fa_index < fa_start)
3042 goto next;
3043
3044 if (fnhe->fnhe_genid != genid)
3045 goto next;
3046
3047 if (fnhe->fnhe_expires &&
3048 time_after(jiffies, fnhe->fnhe_expires))
3049 goto next;
3050
3051 rt = rcu_dereference(fnhe->fnhe_rth_input);
3052 if (!rt)
3053 rt = rcu_dereference(fnhe->fnhe_rth_output);
3054 if (!rt)
3055 goto next;
3056
3057 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
3058 table_id, NULL, skb,
3059 NETLINK_CB(cb->skb).portid,
3060 cb->nlh->nlmsg_seq, flags);
3061 if (err)
3062 return err;
3063next:
3064 (*fa_index)++;
3065 }
3066 }
3067
3068 return 0;
3069}
3070
3071int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3072 u32 table_id, struct fib_info *fi,
3073 int *fa_index, int fa_start, unsigned int flags)
3074{
3075 struct net *net = sock_net(cb->skb->sk);
3076 int nhsel, genid = fnhe_genid(net);
3077
3078 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3079 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3080 struct fnhe_hash_bucket *bucket;
3081 int err;
3082
3083 if (nhc->nhc_flags & RTNH_F_DEAD)
3084 continue;
3085
3086 rcu_read_lock();
3087 bucket = rcu_dereference(nhc->nhc_exceptions);
3088 err = 0;
3089 if (bucket)
3090 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3091 genid, fa_index, fa_start,
3092 flags);
3093 rcu_read_unlock();
3094 if (err)
3095 return err;
3096 }
3097
3098 return 0;
3099}
3100
3101static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3102 u8 ip_proto, __be16 sport,
3103 __be16 dport)
3104{
3105 struct sk_buff *skb;
3106 struct iphdr *iph;
3107
3108 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3109 if (!skb)
3110 return NULL;
3111
3112 /* Reserve room for dummy headers, this skb can pass
3113 * through good chunk of routing engine.
3114 */
3115 skb_reset_mac_header(skb);
3116 skb_reset_network_header(skb);
3117 skb->protocol = htons(ETH_P_IP);
3118 iph = skb_put(skb, sizeof(struct iphdr));
3119 iph->protocol = ip_proto;
3120 iph->saddr = src;
3121 iph->daddr = dst;
3122 iph->version = 0x4;
3123 iph->frag_off = 0;
3124 iph->ihl = 0x5;
3125 skb_set_transport_header(skb, skb->len);
3126
3127 switch (iph->protocol) {
3128 case IPPROTO_UDP: {
3129 struct udphdr *udph;
3130
3131 udph = skb_put_zero(skb, sizeof(struct udphdr));
3132 udph->source = sport;
3133 udph->dest = dport;
3134 udph->len = htons(sizeof(struct udphdr));
3135 udph->check = 0;
3136 break;
3137 }
3138 case IPPROTO_TCP: {
3139 struct tcphdr *tcph;
3140
3141 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3142 tcph->source = sport;
3143 tcph->dest = dport;
3144 tcph->doff = sizeof(struct tcphdr) / 4;
3145 tcph->rst = 1;
3146 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3147 src, dst, 0);
3148 break;
3149 }
3150 case IPPROTO_ICMP: {
3151 struct icmphdr *icmph;
3152
3153 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3154 icmph->type = ICMP_ECHO;
3155 icmph->code = 0;
3156 }
3157 }
3158
3159 return skb;
3160}
3161
3162static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3163 const struct nlmsghdr *nlh,
3164 struct nlattr **tb,
3165 struct netlink_ext_ack *extack)
3166{
3167 struct rtmsg *rtm;
3168 int i, err;
3169
3170 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3171 NL_SET_ERR_MSG(extack,
3172 "ipv4: Invalid header for route get request");
3173 return -EINVAL;
3174 }
3175
3176 if (!netlink_strict_get_check(skb))
3177 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3178 rtm_ipv4_policy, extack);
3179
3180 rtm = nlmsg_data(nlh);
3181 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3182 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3183 rtm->rtm_table || rtm->rtm_protocol ||
3184 rtm->rtm_scope || rtm->rtm_type) {
3185 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3186 return -EINVAL;
3187 }
3188
3189 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3190 RTM_F_LOOKUP_TABLE |
3191 RTM_F_FIB_MATCH)) {
3192 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3193 return -EINVAL;
3194 }
3195
3196 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3197 rtm_ipv4_policy, extack);
3198 if (err)
3199 return err;
3200
3201 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3202 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3203 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3204 return -EINVAL;
3205 }
3206
3207 for (i = 0; i <= RTA_MAX; i++) {
3208 if (!tb[i])
3209 continue;
3210
3211 switch (i) {
3212 case RTA_IIF:
3213 case RTA_OIF:
3214 case RTA_SRC:
3215 case RTA_DST:
3216 case RTA_IP_PROTO:
3217 case RTA_SPORT:
3218 case RTA_DPORT:
3219 case RTA_MARK:
3220 case RTA_UID:
3221 break;
3222 default:
3223 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3224 return -EINVAL;
3225 }
3226 }
3227
3228 return 0;
3229}
3230
3231static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3232 struct netlink_ext_ack *extack)
3233{
3234 struct net *net = sock_net(in_skb->sk);
3235 struct nlattr *tb[RTA_MAX+1];
3236 u32 table_id = RT_TABLE_MAIN;
3237 __be16 sport = 0, dport = 0;
3238 struct fib_result res = {};
3239 u8 ip_proto = IPPROTO_UDP;
3240 struct rtable *rt = NULL;
3241 struct sk_buff *skb;
3242 struct rtmsg *rtm;
3243 struct flowi4 fl4 = {};
3244 __be32 dst = 0;
3245 __be32 src = 0;
3246 kuid_t uid;
3247 u32 iif;
3248 int err;
3249 int mark;
3250
3251 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3252 if (err < 0)
3253 return err;
3254
3255 rtm = nlmsg_data(nlh);
3256 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3257 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3258 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3259 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3260 if (tb[RTA_UID])
3261 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3262 else
3263 uid = (iif ? INVALID_UID : current_uid());
3264
3265 if (tb[RTA_IP_PROTO]) {
3266 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3267 &ip_proto, AF_INET, extack);
3268 if (err)
3269 return err;
3270 }
3271
3272 if (tb[RTA_SPORT])
3273 sport = nla_get_be16(tb[RTA_SPORT]);
3274
3275 if (tb[RTA_DPORT])
3276 dport = nla_get_be16(tb[RTA_DPORT]);
3277
3278 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3279 if (!skb)
3280 return -ENOBUFS;
3281
3282 fl4.daddr = dst;
3283 fl4.saddr = src;
3284 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK;
3285 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3286 fl4.flowi4_mark = mark;
3287 fl4.flowi4_uid = uid;
3288 if (sport)
3289 fl4.fl4_sport = sport;
3290 if (dport)
3291 fl4.fl4_dport = dport;
3292 fl4.flowi4_proto = ip_proto;
3293
3294 rcu_read_lock();
3295
3296 if (iif) {
3297 struct net_device *dev;
3298
3299 dev = dev_get_by_index_rcu(net, iif);
3300 if (!dev) {
3301 err = -ENODEV;
3302 goto errout_rcu;
3303 }
3304
3305 fl4.flowi4_iif = iif; /* for rt_fill_info */
3306 skb->dev = dev;
3307 skb->mark = mark;
3308 err = ip_route_input_rcu(skb, dst, src,
3309 rtm->rtm_tos & IPTOS_RT_MASK, dev,
3310 &res);
3311
3312 rt = skb_rtable(skb);
3313 if (err == 0 && rt->dst.error)
3314 err = -rt->dst.error;
3315 } else {
3316 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3317 skb->dev = net->loopback_dev;
3318 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3319 err = 0;
3320 if (IS_ERR(rt))
3321 err = PTR_ERR(rt);
3322 else
3323 skb_dst_set(skb, &rt->dst);
3324 }
3325
3326 if (err)
3327 goto errout_rcu;
3328
3329 if (rtm->rtm_flags & RTM_F_NOTIFY)
3330 rt->rt_flags |= RTCF_NOTIFY;
3331
3332 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3333 table_id = res.table ? res.table->tb_id : 0;
3334
3335 /* reset skb for netlink reply msg */
3336 skb_trim(skb, 0);
3337 skb_reset_network_header(skb);
3338 skb_reset_transport_header(skb);
3339 skb_reset_mac_header(skb);
3340
3341 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3342 struct fib_rt_info fri;
3343
3344 if (!res.fi) {
3345 err = fib_props[res.type].error;
3346 if (!err)
3347 err = -EHOSTUNREACH;
3348 goto errout_rcu;
3349 }
3350 fri.fi = res.fi;
3351 fri.tb_id = table_id;
3352 fri.dst = res.prefix;
3353 fri.dst_len = res.prefixlen;
3354 fri.dscp = inet_dsfield_to_dscp(fl4.flowi4_tos);
3355 fri.type = rt->rt_type;
3356 fri.offload = 0;
3357 fri.trap = 0;
3358 fri.offload_failed = 0;
3359 if (res.fa_head) {
3360 struct fib_alias *fa;
3361
3362 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3363 u8 slen = 32 - fri.dst_len;
3364
3365 if (fa->fa_slen == slen &&
3366 fa->tb_id == fri.tb_id &&
3367 fa->fa_dscp == fri.dscp &&
3368 fa->fa_info == res.fi &&
3369 fa->fa_type == fri.type) {
3370 fri.offload = READ_ONCE(fa->offload);
3371 fri.trap = READ_ONCE(fa->trap);
3372 fri.offload_failed =
3373 READ_ONCE(fa->offload_failed);
3374 break;
3375 }
3376 }
3377 }
3378 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3379 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3380 } else {
3381 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3382 NETLINK_CB(in_skb).portid,
3383 nlh->nlmsg_seq, 0);
3384 }
3385 if (err < 0)
3386 goto errout_rcu;
3387
3388 rcu_read_unlock();
3389
3390 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3391
3392errout_free:
3393 return err;
3394errout_rcu:
3395 rcu_read_unlock();
3396 kfree_skb(skb);
3397 goto errout_free;
3398}
3399
3400void ip_rt_multicast_event(struct in_device *in_dev)
3401{
3402 rt_cache_flush(dev_net(in_dev->dev));
3403}
3404
3405#ifdef CONFIG_SYSCTL
3406static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3407static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3408static int ip_rt_gc_elasticity __read_mostly = 8;
3409static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3410
3411static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3412 void *buffer, size_t *lenp, loff_t *ppos)
3413{
3414 struct net *net = (struct net *)__ctl->extra1;
3415
3416 if (write) {
3417 rt_cache_flush(net);
3418 fnhe_genid_bump(net);
3419 return 0;
3420 }
3421
3422 return -EINVAL;
3423}
3424
3425static struct ctl_table ipv4_route_table[] = {
3426 {
3427 .procname = "gc_thresh",
3428 .data = &ipv4_dst_ops.gc_thresh,
3429 .maxlen = sizeof(int),
3430 .mode = 0644,
3431 .proc_handler = proc_dointvec,
3432 },
3433 {
3434 .procname = "max_size",
3435 .data = &ip_rt_max_size,
3436 .maxlen = sizeof(int),
3437 .mode = 0644,
3438 .proc_handler = proc_dointvec,
3439 },
3440 {
3441 /* Deprecated. Use gc_min_interval_ms */
3442
3443 .procname = "gc_min_interval",
3444 .data = &ip_rt_gc_min_interval,
3445 .maxlen = sizeof(int),
3446 .mode = 0644,
3447 .proc_handler = proc_dointvec_jiffies,
3448 },
3449 {
3450 .procname = "gc_min_interval_ms",
3451 .data = &ip_rt_gc_min_interval,
3452 .maxlen = sizeof(int),
3453 .mode = 0644,
3454 .proc_handler = proc_dointvec_ms_jiffies,
3455 },
3456 {
3457 .procname = "gc_timeout",
3458 .data = &ip_rt_gc_timeout,
3459 .maxlen = sizeof(int),
3460 .mode = 0644,
3461 .proc_handler = proc_dointvec_jiffies,
3462 },
3463 {
3464 .procname = "gc_interval",
3465 .data = &ip_rt_gc_interval,
3466 .maxlen = sizeof(int),
3467 .mode = 0644,
3468 .proc_handler = proc_dointvec_jiffies,
3469 },
3470 {
3471 .procname = "redirect_load",
3472 .data = &ip_rt_redirect_load,
3473 .maxlen = sizeof(int),
3474 .mode = 0644,
3475 .proc_handler = proc_dointvec,
3476 },
3477 {
3478 .procname = "redirect_number",
3479 .data = &ip_rt_redirect_number,
3480 .maxlen = sizeof(int),
3481 .mode = 0644,
3482 .proc_handler = proc_dointvec,
3483 },
3484 {
3485 .procname = "redirect_silence",
3486 .data = &ip_rt_redirect_silence,
3487 .maxlen = sizeof(int),
3488 .mode = 0644,
3489 .proc_handler = proc_dointvec,
3490 },
3491 {
3492 .procname = "error_cost",
3493 .data = &ip_rt_error_cost,
3494 .maxlen = sizeof(int),
3495 .mode = 0644,
3496 .proc_handler = proc_dointvec,
3497 },
3498 {
3499 .procname = "error_burst",
3500 .data = &ip_rt_error_burst,
3501 .maxlen = sizeof(int),
3502 .mode = 0644,
3503 .proc_handler = proc_dointvec,
3504 },
3505 {
3506 .procname = "gc_elasticity",
3507 .data = &ip_rt_gc_elasticity,
3508 .maxlen = sizeof(int),
3509 .mode = 0644,
3510 .proc_handler = proc_dointvec,
3511 },
3512 { }
3513};
3514
3515static const char ipv4_route_flush_procname[] = "flush";
3516
3517static struct ctl_table ipv4_route_netns_table[] = {
3518 {
3519 .procname = ipv4_route_flush_procname,
3520 .maxlen = sizeof(int),
3521 .mode = 0200,
3522 .proc_handler = ipv4_sysctl_rtcache_flush,
3523 },
3524 {
3525 .procname = "min_pmtu",
3526 .data = &init_net.ipv4.ip_rt_min_pmtu,
3527 .maxlen = sizeof(int),
3528 .mode = 0644,
3529 .proc_handler = proc_dointvec_minmax,
3530 .extra1 = &ip_min_valid_pmtu,
3531 },
3532 {
3533 .procname = "mtu_expires",
3534 .data = &init_net.ipv4.ip_rt_mtu_expires,
3535 .maxlen = sizeof(int),
3536 .mode = 0644,
3537 .proc_handler = proc_dointvec_jiffies,
3538 },
3539 {
3540 .procname = "min_adv_mss",
3541 .data = &init_net.ipv4.ip_rt_min_advmss,
3542 .maxlen = sizeof(int),
3543 .mode = 0644,
3544 .proc_handler = proc_dointvec,
3545 },
3546 { },
3547};
3548
3549static __net_init int sysctl_route_net_init(struct net *net)
3550{
3551 struct ctl_table *tbl;
3552 size_t table_size = ARRAY_SIZE(ipv4_route_netns_table);
3553
3554 tbl = ipv4_route_netns_table;
3555 if (!net_eq(net, &init_net)) {
3556 int i;
3557
3558 tbl = kmemdup(tbl, sizeof(ipv4_route_netns_table), GFP_KERNEL);
3559 if (!tbl)
3560 goto err_dup;
3561
3562 /* Don't export non-whitelisted sysctls to unprivileged users */
3563 if (net->user_ns != &init_user_ns) {
3564 if (tbl[0].procname != ipv4_route_flush_procname) {
3565 tbl[0].procname = NULL;
3566 table_size = 0;
3567 }
3568 }
3569
3570 /* Update the variables to point into the current struct net
3571 * except for the first element flush
3572 */
3573 for (i = 1; i < ARRAY_SIZE(ipv4_route_netns_table) - 1; i++)
3574 tbl[i].data += (void *)net - (void *)&init_net;
3575 }
3576 tbl[0].extra1 = net;
3577
3578 net->ipv4.route_hdr = register_net_sysctl_sz(net, "net/ipv4/route",
3579 tbl, table_size);
3580 if (!net->ipv4.route_hdr)
3581 goto err_reg;
3582 return 0;
3583
3584err_reg:
3585 if (tbl != ipv4_route_netns_table)
3586 kfree(tbl);
3587err_dup:
3588 return -ENOMEM;
3589}
3590
3591static __net_exit void sysctl_route_net_exit(struct net *net)
3592{
3593 struct ctl_table *tbl;
3594
3595 tbl = net->ipv4.route_hdr->ctl_table_arg;
3596 unregister_net_sysctl_table(net->ipv4.route_hdr);
3597 BUG_ON(tbl == ipv4_route_netns_table);
3598 kfree(tbl);
3599}
3600
3601static __net_initdata struct pernet_operations sysctl_route_ops = {
3602 .init = sysctl_route_net_init,
3603 .exit = sysctl_route_net_exit,
3604};
3605#endif
3606
3607static __net_init int netns_ip_rt_init(struct net *net)
3608{
3609 /* Set default value for namespaceified sysctls */
3610 net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU;
3611 net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES;
3612 net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS;
3613 return 0;
3614}
3615
3616static struct pernet_operations __net_initdata ip_rt_ops = {
3617 .init = netns_ip_rt_init,
3618};
3619
3620static __net_init int rt_genid_init(struct net *net)
3621{
3622 atomic_set(&net->ipv4.rt_genid, 0);
3623 atomic_set(&net->fnhe_genid, 0);
3624 atomic_set(&net->ipv4.dev_addr_genid, get_random_u32());
3625 return 0;
3626}
3627
3628static __net_initdata struct pernet_operations rt_genid_ops = {
3629 .init = rt_genid_init,
3630};
3631
3632static int __net_init ipv4_inetpeer_init(struct net *net)
3633{
3634 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3635
3636 if (!bp)
3637 return -ENOMEM;
3638 inet_peer_base_init(bp);
3639 net->ipv4.peers = bp;
3640 return 0;
3641}
3642
3643static void __net_exit ipv4_inetpeer_exit(struct net *net)
3644{
3645 struct inet_peer_base *bp = net->ipv4.peers;
3646
3647 net->ipv4.peers = NULL;
3648 inetpeer_invalidate_tree(bp);
3649 kfree(bp);
3650}
3651
3652static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3653 .init = ipv4_inetpeer_init,
3654 .exit = ipv4_inetpeer_exit,
3655};
3656
3657#ifdef CONFIG_IP_ROUTE_CLASSID
3658struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3659#endif /* CONFIG_IP_ROUTE_CLASSID */
3660
3661int __init ip_rt_init(void)
3662{
3663 void *idents_hash;
3664 int cpu;
3665
3666 /* For modern hosts, this will use 2 MB of memory */
3667 idents_hash = alloc_large_system_hash("IP idents",
3668 sizeof(*ip_idents) + sizeof(*ip_tstamps),
3669 0,
3670 16, /* one bucket per 64 KB */
3671 HASH_ZERO,
3672 NULL,
3673 &ip_idents_mask,
3674 2048,
3675 256*1024);
3676
3677 ip_idents = idents_hash;
3678
3679 get_random_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
3680
3681 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3682
3683 for_each_possible_cpu(cpu) {
3684 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3685
3686 INIT_LIST_HEAD(&ul->head);
3687 INIT_LIST_HEAD(&ul->quarantine);
3688 spin_lock_init(&ul->lock);
3689 }
3690#ifdef CONFIG_IP_ROUTE_CLASSID
3691 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3692 if (!ip_rt_acct)
3693 panic("IP: failed to allocate ip_rt_acct\n");
3694#endif
3695
3696 ipv4_dst_ops.kmem_cachep =
3697 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3698 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3699
3700 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3701
3702 if (dst_entries_init(&ipv4_dst_ops) < 0)
3703 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3704
3705 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3706 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3707
3708 ipv4_dst_ops.gc_thresh = ~0;
3709 ip_rt_max_size = INT_MAX;
3710
3711 devinet_init();
3712 ip_fib_init();
3713
3714 if (ip_rt_proc_init())
3715 pr_err("Unable to create route proc files\n");
3716#ifdef CONFIG_XFRM
3717 xfrm_init();
3718 xfrm4_init();
3719#endif
3720 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3721 RTNL_FLAG_DOIT_UNLOCKED);
3722
3723#ifdef CONFIG_SYSCTL
3724 register_pernet_subsys(&sysctl_route_ops);
3725#endif
3726 register_pernet_subsys(&ip_rt_ops);
3727 register_pernet_subsys(&rt_genid_ops);
3728 register_pernet_subsys(&ipv4_inetpeer_ops);
3729 return 0;
3730}
3731
3732#ifdef CONFIG_SYSCTL
3733/*
3734 * We really need to sanitize the damn ipv4 init order, then all
3735 * this nonsense will go away.
3736 */
3737void __init ip_static_sysctl_init(void)
3738{
3739 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3740}
3741#endif