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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * ROUTE - implementation of the IP router.
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Alan Cox, <gw4pts@gw4pts.ampr.org>
12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
14 *
15 * Fixes:
16 * Alan Cox : Verify area fixes.
17 * Alan Cox : cli() protects routing changes
18 * Rui Oliveira : ICMP routing table updates
19 * (rco@di.uminho.pt) Routing table insertion and update
20 * Linus Torvalds : Rewrote bits to be sensible
21 * Alan Cox : Added BSD route gw semantics
22 * Alan Cox : Super /proc >4K
23 * Alan Cox : MTU in route table
24 * Alan Cox : MSS actually. Also added the window
25 * clamper.
26 * Sam Lantinga : Fixed route matching in rt_del()
27 * Alan Cox : Routing cache support.
28 * Alan Cox : Removed compatibility cruft.
29 * Alan Cox : RTF_REJECT support.
30 * Alan Cox : TCP irtt support.
31 * Jonathan Naylor : Added Metric support.
32 * Miquel van Smoorenburg : BSD API fixes.
33 * Miquel van Smoorenburg : Metrics.
34 * Alan Cox : Use __u32 properly
35 * Alan Cox : Aligned routing errors more closely with BSD
36 * our system is still very different.
37 * Alan Cox : Faster /proc handling
38 * Alexey Kuznetsov : Massive rework to support tree based routing,
39 * routing caches and better behaviour.
40 *
41 * Olaf Erb : irtt wasn't being copied right.
42 * Bjorn Ekwall : Kerneld route support.
43 * Alan Cox : Multicast fixed (I hope)
44 * Pavel Krauz : Limited broadcast fixed
45 * Mike McLagan : Routing by source
46 * Alexey Kuznetsov : End of old history. Split to fib.c and
47 * route.c and rewritten from scratch.
48 * Andi Kleen : Load-limit warning messages.
49 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
53 * Marc Boucher : routing by fwmark
54 * Robert Olsson : Added rt_cache statistics
55 * Arnaldo C. Melo : Convert proc stuff to seq_file
56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
58 * Ilia Sotnikov : Removed TOS from hash calculations
59 */
60
61#define pr_fmt(fmt) "IPv4: " fmt
62
63#include <linux/module.h>
64#include <linux/uaccess.h>
65#include <linux/bitops.h>
66#include <linux/types.h>
67#include <linux/kernel.h>
68#include <linux/mm.h>
69#include <linux/string.h>
70#include <linux/socket.h>
71#include <linux/sockios.h>
72#include <linux/errno.h>
73#include <linux/in.h>
74#include <linux/inet.h>
75#include <linux/netdevice.h>
76#include <linux/proc_fs.h>
77#include <linux/init.h>
78#include <linux/skbuff.h>
79#include <linux/inetdevice.h>
80#include <linux/igmp.h>
81#include <linux/pkt_sched.h>
82#include <linux/mroute.h>
83#include <linux/netfilter_ipv4.h>
84#include <linux/random.h>
85#include <linux/rcupdate.h>
86#include <linux/times.h>
87#include <linux/slab.h>
88#include <linux/jhash.h>
89#include <net/dst.h>
90#include <net/dst_metadata.h>
91#include <net/net_namespace.h>
92#include <net/protocol.h>
93#include <net/ip.h>
94#include <net/route.h>
95#include <net/inetpeer.h>
96#include <net/sock.h>
97#include <net/ip_fib.h>
98#include <net/nexthop.h>
99#include <net/arp.h>
100#include <net/tcp.h>
101#include <net/icmp.h>
102#include <net/xfrm.h>
103#include <net/lwtunnel.h>
104#include <net/netevent.h>
105#include <net/rtnetlink.h>
106#ifdef CONFIG_SYSCTL
107#include <linux/sysctl.h>
108#endif
109#include <net/secure_seq.h>
110#include <net/ip_tunnels.h>
111#include <net/l3mdev.h>
112
113#include "fib_lookup.h"
114
115#define RT_FL_TOS(oldflp4) \
116 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
117
118#define RT_GC_TIMEOUT (300*HZ)
119
120static int ip_rt_max_size;
121static int ip_rt_redirect_number __read_mostly = 9;
122static int ip_rt_redirect_load __read_mostly = HZ / 50;
123static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
124static int ip_rt_error_cost __read_mostly = HZ;
125static int ip_rt_error_burst __read_mostly = 5 * HZ;
126static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
127static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
128static int ip_rt_min_advmss __read_mostly = 256;
129
130static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
131
132/*
133 * Interface to generic destination cache.
134 */
135
136static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
137static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
138static unsigned int ipv4_mtu(const struct dst_entry *dst);
139static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
140static void ipv4_link_failure(struct sk_buff *skb);
141static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
142 struct sk_buff *skb, u32 mtu,
143 bool confirm_neigh);
144static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146static void ipv4_dst_destroy(struct dst_entry *dst);
147
148static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
149{
150 WARN_ON(1);
151 return NULL;
152}
153
154static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
155 struct sk_buff *skb,
156 const void *daddr);
157static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
158
159static struct dst_ops ipv4_dst_ops = {
160 .family = AF_INET,
161 .check = ipv4_dst_check,
162 .default_advmss = ipv4_default_advmss,
163 .mtu = ipv4_mtu,
164 .cow_metrics = ipv4_cow_metrics,
165 .destroy = ipv4_dst_destroy,
166 .negative_advice = ipv4_negative_advice,
167 .link_failure = ipv4_link_failure,
168 .update_pmtu = ip_rt_update_pmtu,
169 .redirect = ip_do_redirect,
170 .local_out = __ip_local_out,
171 .neigh_lookup = ipv4_neigh_lookup,
172 .confirm_neigh = ipv4_confirm_neigh,
173};
174
175#define ECN_OR_COST(class) TC_PRIO_##class
176
177const __u8 ip_tos2prio[16] = {
178 TC_PRIO_BESTEFFORT,
179 ECN_OR_COST(BESTEFFORT),
180 TC_PRIO_BESTEFFORT,
181 ECN_OR_COST(BESTEFFORT),
182 TC_PRIO_BULK,
183 ECN_OR_COST(BULK),
184 TC_PRIO_BULK,
185 ECN_OR_COST(BULK),
186 TC_PRIO_INTERACTIVE,
187 ECN_OR_COST(INTERACTIVE),
188 TC_PRIO_INTERACTIVE,
189 ECN_OR_COST(INTERACTIVE),
190 TC_PRIO_INTERACTIVE_BULK,
191 ECN_OR_COST(INTERACTIVE_BULK),
192 TC_PRIO_INTERACTIVE_BULK,
193 ECN_OR_COST(INTERACTIVE_BULK)
194};
195EXPORT_SYMBOL(ip_tos2prio);
196
197static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
198#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
199
200#ifdef CONFIG_PROC_FS
201static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
202{
203 if (*pos)
204 return NULL;
205 return SEQ_START_TOKEN;
206}
207
208static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
209{
210 ++*pos;
211 return NULL;
212}
213
214static void rt_cache_seq_stop(struct seq_file *seq, void *v)
215{
216}
217
218static int rt_cache_seq_show(struct seq_file *seq, void *v)
219{
220 if (v == SEQ_START_TOKEN)
221 seq_printf(seq, "%-127s\n",
222 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
223 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
224 "HHUptod\tSpecDst");
225 return 0;
226}
227
228static const struct seq_operations rt_cache_seq_ops = {
229 .start = rt_cache_seq_start,
230 .next = rt_cache_seq_next,
231 .stop = rt_cache_seq_stop,
232 .show = rt_cache_seq_show,
233};
234
235static int rt_cache_seq_open(struct inode *inode, struct file *file)
236{
237 return seq_open(file, &rt_cache_seq_ops);
238}
239
240static const struct proc_ops rt_cache_proc_ops = {
241 .proc_open = rt_cache_seq_open,
242 .proc_read = seq_read,
243 .proc_lseek = seq_lseek,
244 .proc_release = seq_release,
245};
246
247
248static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
249{
250 int cpu;
251
252 if (*pos == 0)
253 return SEQ_START_TOKEN;
254
255 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
256 if (!cpu_possible(cpu))
257 continue;
258 *pos = cpu+1;
259 return &per_cpu(rt_cache_stat, cpu);
260 }
261 return NULL;
262}
263
264static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
265{
266 int cpu;
267
268 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
269 if (!cpu_possible(cpu))
270 continue;
271 *pos = cpu+1;
272 return &per_cpu(rt_cache_stat, cpu);
273 }
274 (*pos)++;
275 return NULL;
276
277}
278
279static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
280{
281
282}
283
284static int rt_cpu_seq_show(struct seq_file *seq, void *v)
285{
286 struct rt_cache_stat *st = v;
287
288 if (v == SEQ_START_TOKEN) {
289 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");
290 return 0;
291 }
292
293 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x "
294 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
295 dst_entries_get_slow(&ipv4_dst_ops),
296 0, /* st->in_hit */
297 st->in_slow_tot,
298 st->in_slow_mc,
299 st->in_no_route,
300 st->in_brd,
301 st->in_martian_dst,
302 st->in_martian_src,
303
304 0, /* st->out_hit */
305 st->out_slow_tot,
306 st->out_slow_mc,
307
308 0, /* st->gc_total */
309 0, /* st->gc_ignored */
310 0, /* st->gc_goal_miss */
311 0, /* st->gc_dst_overflow */
312 0, /* st->in_hlist_search */
313 0 /* st->out_hlist_search */
314 );
315 return 0;
316}
317
318static const struct seq_operations rt_cpu_seq_ops = {
319 .start = rt_cpu_seq_start,
320 .next = rt_cpu_seq_next,
321 .stop = rt_cpu_seq_stop,
322 .show = rt_cpu_seq_show,
323};
324
325
326static int rt_cpu_seq_open(struct inode *inode, struct file *file)
327{
328 return seq_open(file, &rt_cpu_seq_ops);
329}
330
331static const struct proc_ops rt_cpu_proc_ops = {
332 .proc_open = rt_cpu_seq_open,
333 .proc_read = seq_read,
334 .proc_lseek = seq_lseek,
335 .proc_release = seq_release,
336};
337
338#ifdef CONFIG_IP_ROUTE_CLASSID
339static int rt_acct_proc_show(struct seq_file *m, void *v)
340{
341 struct ip_rt_acct *dst, *src;
342 unsigned int i, j;
343
344 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
345 if (!dst)
346 return -ENOMEM;
347
348 for_each_possible_cpu(i) {
349 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
350 for (j = 0; j < 256; j++) {
351 dst[j].o_bytes += src[j].o_bytes;
352 dst[j].o_packets += src[j].o_packets;
353 dst[j].i_bytes += src[j].i_bytes;
354 dst[j].i_packets += src[j].i_packets;
355 }
356 }
357
358 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
359 kfree(dst);
360 return 0;
361}
362#endif
363
364static int __net_init ip_rt_do_proc_init(struct net *net)
365{
366 struct proc_dir_entry *pde;
367
368 pde = proc_create("rt_cache", 0444, net->proc_net,
369 &rt_cache_proc_ops);
370 if (!pde)
371 goto err1;
372
373 pde = proc_create("rt_cache", 0444,
374 net->proc_net_stat, &rt_cpu_proc_ops);
375 if (!pde)
376 goto err2;
377
378#ifdef CONFIG_IP_ROUTE_CLASSID
379 pde = proc_create_single("rt_acct", 0, net->proc_net,
380 rt_acct_proc_show);
381 if (!pde)
382 goto err3;
383#endif
384 return 0;
385
386#ifdef CONFIG_IP_ROUTE_CLASSID
387err3:
388 remove_proc_entry("rt_cache", net->proc_net_stat);
389#endif
390err2:
391 remove_proc_entry("rt_cache", net->proc_net);
392err1:
393 return -ENOMEM;
394}
395
396static void __net_exit ip_rt_do_proc_exit(struct net *net)
397{
398 remove_proc_entry("rt_cache", net->proc_net_stat);
399 remove_proc_entry("rt_cache", net->proc_net);
400#ifdef CONFIG_IP_ROUTE_CLASSID
401 remove_proc_entry("rt_acct", net->proc_net);
402#endif
403}
404
405static struct pernet_operations ip_rt_proc_ops __net_initdata = {
406 .init = ip_rt_do_proc_init,
407 .exit = ip_rt_do_proc_exit,
408};
409
410static int __init ip_rt_proc_init(void)
411{
412 return register_pernet_subsys(&ip_rt_proc_ops);
413}
414
415#else
416static inline int ip_rt_proc_init(void)
417{
418 return 0;
419}
420#endif /* CONFIG_PROC_FS */
421
422static inline bool rt_is_expired(const struct rtable *rth)
423{
424 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
425}
426
427void rt_cache_flush(struct net *net)
428{
429 rt_genid_bump_ipv4(net);
430}
431
432static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
433 struct sk_buff *skb,
434 const void *daddr)
435{
436 const struct rtable *rt = container_of(dst, struct rtable, dst);
437 struct net_device *dev = dst->dev;
438 struct neighbour *n;
439
440 rcu_read_lock_bh();
441
442 if (likely(rt->rt_gw_family == AF_INET)) {
443 n = ip_neigh_gw4(dev, rt->rt_gw4);
444 } else if (rt->rt_gw_family == AF_INET6) {
445 n = ip_neigh_gw6(dev, &rt->rt_gw6);
446 } else {
447 __be32 pkey;
448
449 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
450 n = ip_neigh_gw4(dev, pkey);
451 }
452
453 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
454 n = NULL;
455
456 rcu_read_unlock_bh();
457
458 return n;
459}
460
461static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
462{
463 const struct rtable *rt = container_of(dst, struct rtable, dst);
464 struct net_device *dev = dst->dev;
465 const __be32 *pkey = daddr;
466
467 if (rt->rt_gw_family == AF_INET) {
468 pkey = (const __be32 *)&rt->rt_gw4;
469 } else if (rt->rt_gw_family == AF_INET6) {
470 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
471 } else if (!daddr ||
472 (rt->rt_flags &
473 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
474 return;
475 }
476 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
477}
478
479#define IP_IDENTS_SZ 2048u
480
481static atomic_t *ip_idents __read_mostly;
482static u32 *ip_tstamps __read_mostly;
483
484/* In order to protect privacy, we add a perturbation to identifiers
485 * if one generator is seldom used. This makes hard for an attacker
486 * to infer how many packets were sent between two points in time.
487 */
488u32 ip_idents_reserve(u32 hash, int segs)
489{
490 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ;
491 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ;
492 u32 old = READ_ONCE(*p_tstamp);
493 u32 now = (u32)jiffies;
494 u32 delta = 0;
495
496 if (old != now && cmpxchg(p_tstamp, old, now) == old)
497 delta = prandom_u32_max(now - old);
498
499 /* If UBSAN reports an error there, please make sure your compiler
500 * supports -fno-strict-overflow before reporting it that was a bug
501 * in UBSAN, and it has been fixed in GCC-8.
502 */
503 return atomic_add_return(segs + delta, p_id) - segs;
504}
505EXPORT_SYMBOL(ip_idents_reserve);
506
507void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
508{
509 u32 hash, id;
510
511 /* Note the following code is not safe, but this is okay. */
512 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
513 get_random_bytes(&net->ipv4.ip_id_key,
514 sizeof(net->ipv4.ip_id_key));
515
516 hash = siphash_3u32((__force u32)iph->daddr,
517 (__force u32)iph->saddr,
518 iph->protocol,
519 &net->ipv4.ip_id_key);
520 id = ip_idents_reserve(hash, segs);
521 iph->id = htons(id);
522}
523EXPORT_SYMBOL(__ip_select_ident);
524
525static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
526 const struct sock *sk,
527 const struct iphdr *iph,
528 int oif, u8 tos,
529 u8 prot, u32 mark, int flow_flags)
530{
531 if (sk) {
532 const struct inet_sock *inet = inet_sk(sk);
533
534 oif = sk->sk_bound_dev_if;
535 mark = sk->sk_mark;
536 tos = RT_CONN_FLAGS(sk);
537 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
538 }
539 flowi4_init_output(fl4, oif, mark, tos,
540 RT_SCOPE_UNIVERSE, prot,
541 flow_flags,
542 iph->daddr, iph->saddr, 0, 0,
543 sock_net_uid(net, sk));
544}
545
546static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
547 const struct sock *sk)
548{
549 const struct net *net = dev_net(skb->dev);
550 const struct iphdr *iph = ip_hdr(skb);
551 int oif = skb->dev->ifindex;
552 u8 tos = RT_TOS(iph->tos);
553 u8 prot = iph->protocol;
554 u32 mark = skb->mark;
555
556 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
557}
558
559static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
560{
561 const struct inet_sock *inet = inet_sk(sk);
562 const struct ip_options_rcu *inet_opt;
563 __be32 daddr = inet->inet_daddr;
564
565 rcu_read_lock();
566 inet_opt = rcu_dereference(inet->inet_opt);
567 if (inet_opt && inet_opt->opt.srr)
568 daddr = inet_opt->opt.faddr;
569 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
570 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
571 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
572 inet_sk_flowi_flags(sk),
573 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
574 rcu_read_unlock();
575}
576
577static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
578 const struct sk_buff *skb)
579{
580 if (skb)
581 build_skb_flow_key(fl4, skb, sk);
582 else
583 build_sk_flow_key(fl4, sk);
584}
585
586static DEFINE_SPINLOCK(fnhe_lock);
587
588static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
589{
590 struct rtable *rt;
591
592 rt = rcu_dereference(fnhe->fnhe_rth_input);
593 if (rt) {
594 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
595 dst_dev_put(&rt->dst);
596 dst_release(&rt->dst);
597 }
598 rt = rcu_dereference(fnhe->fnhe_rth_output);
599 if (rt) {
600 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
601 dst_dev_put(&rt->dst);
602 dst_release(&rt->dst);
603 }
604}
605
606static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
607{
608 struct fib_nh_exception *fnhe, *oldest;
609
610 oldest = rcu_dereference(hash->chain);
611 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
612 fnhe = rcu_dereference(fnhe->fnhe_next)) {
613 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
614 oldest = fnhe;
615 }
616 fnhe_flush_routes(oldest);
617 return oldest;
618}
619
620static inline u32 fnhe_hashfun(__be32 daddr)
621{
622 static u32 fnhe_hashrnd __read_mostly;
623 u32 hval;
624
625 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
626 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
627 return hash_32(hval, FNHE_HASH_SHIFT);
628}
629
630static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
631{
632 rt->rt_pmtu = fnhe->fnhe_pmtu;
633 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
634 rt->dst.expires = fnhe->fnhe_expires;
635
636 if (fnhe->fnhe_gw) {
637 rt->rt_flags |= RTCF_REDIRECTED;
638 rt->rt_uses_gateway = 1;
639 rt->rt_gw_family = AF_INET;
640 rt->rt_gw4 = fnhe->fnhe_gw;
641 }
642}
643
644static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
645 __be32 gw, u32 pmtu, bool lock,
646 unsigned long expires)
647{
648 struct fnhe_hash_bucket *hash;
649 struct fib_nh_exception *fnhe;
650 struct rtable *rt;
651 u32 genid, hval;
652 unsigned int i;
653 int depth;
654
655 genid = fnhe_genid(dev_net(nhc->nhc_dev));
656 hval = fnhe_hashfun(daddr);
657
658 spin_lock_bh(&fnhe_lock);
659
660 hash = rcu_dereference(nhc->nhc_exceptions);
661 if (!hash) {
662 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
663 if (!hash)
664 goto out_unlock;
665 rcu_assign_pointer(nhc->nhc_exceptions, hash);
666 }
667
668 hash += hval;
669
670 depth = 0;
671 for (fnhe = rcu_dereference(hash->chain); fnhe;
672 fnhe = rcu_dereference(fnhe->fnhe_next)) {
673 if (fnhe->fnhe_daddr == daddr)
674 break;
675 depth++;
676 }
677
678 if (fnhe) {
679 if (fnhe->fnhe_genid != genid)
680 fnhe->fnhe_genid = genid;
681 if (gw)
682 fnhe->fnhe_gw = gw;
683 if (pmtu) {
684 fnhe->fnhe_pmtu = pmtu;
685 fnhe->fnhe_mtu_locked = lock;
686 }
687 fnhe->fnhe_expires = max(1UL, expires);
688 /* Update all cached dsts too */
689 rt = rcu_dereference(fnhe->fnhe_rth_input);
690 if (rt)
691 fill_route_from_fnhe(rt, fnhe);
692 rt = rcu_dereference(fnhe->fnhe_rth_output);
693 if (rt)
694 fill_route_from_fnhe(rt, fnhe);
695 } else {
696 if (depth > FNHE_RECLAIM_DEPTH)
697 fnhe = fnhe_oldest(hash);
698 else {
699 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
700 if (!fnhe)
701 goto out_unlock;
702
703 fnhe->fnhe_next = hash->chain;
704 rcu_assign_pointer(hash->chain, fnhe);
705 }
706 fnhe->fnhe_genid = genid;
707 fnhe->fnhe_daddr = daddr;
708 fnhe->fnhe_gw = gw;
709 fnhe->fnhe_pmtu = pmtu;
710 fnhe->fnhe_mtu_locked = lock;
711 fnhe->fnhe_expires = max(1UL, expires);
712
713 /* Exception created; mark the cached routes for the nexthop
714 * stale, so anyone caching it rechecks if this exception
715 * applies to them.
716 */
717 rt = rcu_dereference(nhc->nhc_rth_input);
718 if (rt)
719 rt->dst.obsolete = DST_OBSOLETE_KILL;
720
721 for_each_possible_cpu(i) {
722 struct rtable __rcu **prt;
723 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
724 rt = rcu_dereference(*prt);
725 if (rt)
726 rt->dst.obsolete = DST_OBSOLETE_KILL;
727 }
728 }
729
730 fnhe->fnhe_stamp = jiffies;
731
732out_unlock:
733 spin_unlock_bh(&fnhe_lock);
734}
735
736static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
737 bool kill_route)
738{
739 __be32 new_gw = icmp_hdr(skb)->un.gateway;
740 __be32 old_gw = ip_hdr(skb)->saddr;
741 struct net_device *dev = skb->dev;
742 struct in_device *in_dev;
743 struct fib_result res;
744 struct neighbour *n;
745 struct net *net;
746
747 switch (icmp_hdr(skb)->code & 7) {
748 case ICMP_REDIR_NET:
749 case ICMP_REDIR_NETTOS:
750 case ICMP_REDIR_HOST:
751 case ICMP_REDIR_HOSTTOS:
752 break;
753
754 default:
755 return;
756 }
757
758 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
759 return;
760
761 in_dev = __in_dev_get_rcu(dev);
762 if (!in_dev)
763 return;
764
765 net = dev_net(dev);
766 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
767 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
768 ipv4_is_zeronet(new_gw))
769 goto reject_redirect;
770
771 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
772 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
773 goto reject_redirect;
774 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
775 goto reject_redirect;
776 } else {
777 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
778 goto reject_redirect;
779 }
780
781 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
782 if (!n)
783 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
784 if (!IS_ERR(n)) {
785 if (!(n->nud_state & NUD_VALID)) {
786 neigh_event_send(n, NULL);
787 } else {
788 if (fib_lookup(net, fl4, &res, 0) == 0) {
789 struct fib_nh_common *nhc;
790
791 fib_select_path(net, &res, fl4, skb);
792 nhc = FIB_RES_NHC(res);
793 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
794 0, false,
795 jiffies + ip_rt_gc_timeout);
796 }
797 if (kill_route)
798 rt->dst.obsolete = DST_OBSOLETE_KILL;
799 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
800 }
801 neigh_release(n);
802 }
803 return;
804
805reject_redirect:
806#ifdef CONFIG_IP_ROUTE_VERBOSE
807 if (IN_DEV_LOG_MARTIANS(in_dev)) {
808 const struct iphdr *iph = (const struct iphdr *) skb->data;
809 __be32 daddr = iph->daddr;
810 __be32 saddr = iph->saddr;
811
812 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
813 " Advised path = %pI4 -> %pI4\n",
814 &old_gw, dev->name, &new_gw,
815 &saddr, &daddr);
816 }
817#endif
818 ;
819}
820
821static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
822{
823 struct rtable *rt;
824 struct flowi4 fl4;
825 const struct iphdr *iph = (const struct iphdr *) skb->data;
826 struct net *net = dev_net(skb->dev);
827 int oif = skb->dev->ifindex;
828 u8 tos = RT_TOS(iph->tos);
829 u8 prot = iph->protocol;
830 u32 mark = skb->mark;
831
832 rt = (struct rtable *) dst;
833
834 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
835 __ip_do_redirect(rt, skb, &fl4, true);
836}
837
838static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
839{
840 struct rtable *rt = (struct rtable *)dst;
841 struct dst_entry *ret = dst;
842
843 if (rt) {
844 if (dst->obsolete > 0) {
845 ip_rt_put(rt);
846 ret = NULL;
847 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
848 rt->dst.expires) {
849 ip_rt_put(rt);
850 ret = NULL;
851 }
852 }
853 return ret;
854}
855
856/*
857 * Algorithm:
858 * 1. The first ip_rt_redirect_number redirects are sent
859 * with exponential backoff, then we stop sending them at all,
860 * assuming that the host ignores our redirects.
861 * 2. If we did not see packets requiring redirects
862 * during ip_rt_redirect_silence, we assume that the host
863 * forgot redirected route and start to send redirects again.
864 *
865 * This algorithm is much cheaper and more intelligent than dumb load limiting
866 * in icmp.c.
867 *
868 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
869 * and "frag. need" (breaks PMTU discovery) in icmp.c.
870 */
871
872void ip_rt_send_redirect(struct sk_buff *skb)
873{
874 struct rtable *rt = skb_rtable(skb);
875 struct in_device *in_dev;
876 struct inet_peer *peer;
877 struct net *net;
878 int log_martians;
879 int vif;
880
881 rcu_read_lock();
882 in_dev = __in_dev_get_rcu(rt->dst.dev);
883 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
884 rcu_read_unlock();
885 return;
886 }
887 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
888 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
889 rcu_read_unlock();
890
891 net = dev_net(rt->dst.dev);
892 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
893 if (!peer) {
894 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
895 rt_nexthop(rt, ip_hdr(skb)->daddr));
896 return;
897 }
898
899 /* No redirected packets during ip_rt_redirect_silence;
900 * reset the algorithm.
901 */
902 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
903 peer->rate_tokens = 0;
904 peer->n_redirects = 0;
905 }
906
907 /* Too many ignored redirects; do not send anything
908 * set dst.rate_last to the last seen redirected packet.
909 */
910 if (peer->n_redirects >= ip_rt_redirect_number) {
911 peer->rate_last = jiffies;
912 goto out_put_peer;
913 }
914
915 /* Check for load limit; set rate_last to the latest sent
916 * redirect.
917 */
918 if (peer->n_redirects == 0 ||
919 time_after(jiffies,
920 (peer->rate_last +
921 (ip_rt_redirect_load << peer->n_redirects)))) {
922 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
923
924 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
925 peer->rate_last = jiffies;
926 ++peer->n_redirects;
927#ifdef CONFIG_IP_ROUTE_VERBOSE
928 if (log_martians &&
929 peer->n_redirects == ip_rt_redirect_number)
930 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
931 &ip_hdr(skb)->saddr, inet_iif(skb),
932 &ip_hdr(skb)->daddr, &gw);
933#endif
934 }
935out_put_peer:
936 inet_putpeer(peer);
937}
938
939static int ip_error(struct sk_buff *skb)
940{
941 struct rtable *rt = skb_rtable(skb);
942 struct net_device *dev = skb->dev;
943 struct in_device *in_dev;
944 struct inet_peer *peer;
945 unsigned long now;
946 struct net *net;
947 bool send;
948 int code;
949
950 if (netif_is_l3_master(skb->dev)) {
951 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
952 if (!dev)
953 goto out;
954 }
955
956 in_dev = __in_dev_get_rcu(dev);
957
958 /* IP on this device is disabled. */
959 if (!in_dev)
960 goto out;
961
962 net = dev_net(rt->dst.dev);
963 if (!IN_DEV_FORWARD(in_dev)) {
964 switch (rt->dst.error) {
965 case EHOSTUNREACH:
966 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
967 break;
968
969 case ENETUNREACH:
970 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
971 break;
972 }
973 goto out;
974 }
975
976 switch (rt->dst.error) {
977 case EINVAL:
978 default:
979 goto out;
980 case EHOSTUNREACH:
981 code = ICMP_HOST_UNREACH;
982 break;
983 case ENETUNREACH:
984 code = ICMP_NET_UNREACH;
985 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
986 break;
987 case EACCES:
988 code = ICMP_PKT_FILTERED;
989 break;
990 }
991
992 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
993 l3mdev_master_ifindex(skb->dev), 1);
994
995 send = true;
996 if (peer) {
997 now = jiffies;
998 peer->rate_tokens += now - peer->rate_last;
999 if (peer->rate_tokens > ip_rt_error_burst)
1000 peer->rate_tokens = ip_rt_error_burst;
1001 peer->rate_last = now;
1002 if (peer->rate_tokens >= ip_rt_error_cost)
1003 peer->rate_tokens -= ip_rt_error_cost;
1004 else
1005 send = false;
1006 inet_putpeer(peer);
1007 }
1008 if (send)
1009 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1010
1011out: kfree_skb(skb);
1012 return 0;
1013}
1014
1015static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1016{
1017 struct dst_entry *dst = &rt->dst;
1018 struct net *net = dev_net(dst->dev);
1019 u32 old_mtu = ipv4_mtu(dst);
1020 struct fib_result res;
1021 bool lock = false;
1022
1023 if (ip_mtu_locked(dst))
1024 return;
1025
1026 if (old_mtu < mtu)
1027 return;
1028
1029 if (mtu < ip_rt_min_pmtu) {
1030 lock = true;
1031 mtu = min(old_mtu, ip_rt_min_pmtu);
1032 }
1033
1034 if (rt->rt_pmtu == mtu && !lock &&
1035 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1036 return;
1037
1038 rcu_read_lock();
1039 if (fib_lookup(net, fl4, &res, 0) == 0) {
1040 struct fib_nh_common *nhc;
1041
1042 fib_select_path(net, &res, fl4, NULL);
1043 nhc = FIB_RES_NHC(res);
1044 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1045 jiffies + ip_rt_mtu_expires);
1046 }
1047 rcu_read_unlock();
1048}
1049
1050static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1051 struct sk_buff *skb, u32 mtu,
1052 bool confirm_neigh)
1053{
1054 struct rtable *rt = (struct rtable *) dst;
1055 struct flowi4 fl4;
1056
1057 ip_rt_build_flow_key(&fl4, sk, skb);
1058
1059 /* Don't make lookup fail for bridged encapsulations */
1060 if (skb && netif_is_any_bridge_port(skb->dev))
1061 fl4.flowi4_oif = 0;
1062
1063 __ip_rt_update_pmtu(rt, &fl4, mtu);
1064}
1065
1066void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1067 int oif, u8 protocol)
1068{
1069 const struct iphdr *iph = (const struct iphdr *) skb->data;
1070 struct flowi4 fl4;
1071 struct rtable *rt;
1072 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1073
1074 __build_flow_key(net, &fl4, NULL, iph, oif,
1075 RT_TOS(iph->tos), protocol, mark, 0);
1076 rt = __ip_route_output_key(net, &fl4);
1077 if (!IS_ERR(rt)) {
1078 __ip_rt_update_pmtu(rt, &fl4, mtu);
1079 ip_rt_put(rt);
1080 }
1081}
1082EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1083
1084static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1085{
1086 const struct iphdr *iph = (const struct iphdr *) skb->data;
1087 struct flowi4 fl4;
1088 struct rtable *rt;
1089
1090 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1091
1092 if (!fl4.flowi4_mark)
1093 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1094
1095 rt = __ip_route_output_key(sock_net(sk), &fl4);
1096 if (!IS_ERR(rt)) {
1097 __ip_rt_update_pmtu(rt, &fl4, mtu);
1098 ip_rt_put(rt);
1099 }
1100}
1101
1102void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1103{
1104 const struct iphdr *iph = (const struct iphdr *) skb->data;
1105 struct flowi4 fl4;
1106 struct rtable *rt;
1107 struct dst_entry *odst = NULL;
1108 bool new = false;
1109 struct net *net = sock_net(sk);
1110
1111 bh_lock_sock(sk);
1112
1113 if (!ip_sk_accept_pmtu(sk))
1114 goto out;
1115
1116 odst = sk_dst_get(sk);
1117
1118 if (sock_owned_by_user(sk) || !odst) {
1119 __ipv4_sk_update_pmtu(skb, sk, mtu);
1120 goto out;
1121 }
1122
1123 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1124
1125 rt = (struct rtable *)odst;
1126 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1127 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1128 if (IS_ERR(rt))
1129 goto out;
1130
1131 new = true;
1132 }
1133
1134 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1135
1136 if (!dst_check(&rt->dst, 0)) {
1137 if (new)
1138 dst_release(&rt->dst);
1139
1140 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1141 if (IS_ERR(rt))
1142 goto out;
1143
1144 new = true;
1145 }
1146
1147 if (new)
1148 sk_dst_set(sk, &rt->dst);
1149
1150out:
1151 bh_unlock_sock(sk);
1152 dst_release(odst);
1153}
1154EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1155
1156void ipv4_redirect(struct sk_buff *skb, struct net *net,
1157 int oif, u8 protocol)
1158{
1159 const struct iphdr *iph = (const struct iphdr *) skb->data;
1160 struct flowi4 fl4;
1161 struct rtable *rt;
1162
1163 __build_flow_key(net, &fl4, NULL, iph, oif,
1164 RT_TOS(iph->tos), protocol, 0, 0);
1165 rt = __ip_route_output_key(net, &fl4);
1166 if (!IS_ERR(rt)) {
1167 __ip_do_redirect(rt, skb, &fl4, false);
1168 ip_rt_put(rt);
1169 }
1170}
1171EXPORT_SYMBOL_GPL(ipv4_redirect);
1172
1173void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1174{
1175 const struct iphdr *iph = (const struct iphdr *) skb->data;
1176 struct flowi4 fl4;
1177 struct rtable *rt;
1178 struct net *net = sock_net(sk);
1179
1180 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1181 rt = __ip_route_output_key(net, &fl4);
1182 if (!IS_ERR(rt)) {
1183 __ip_do_redirect(rt, skb, &fl4, false);
1184 ip_rt_put(rt);
1185 }
1186}
1187EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1188
1189static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1190{
1191 struct rtable *rt = (struct rtable *) dst;
1192
1193 /* All IPV4 dsts are created with ->obsolete set to the value
1194 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1195 * into this function always.
1196 *
1197 * When a PMTU/redirect information update invalidates a route,
1198 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1199 * DST_OBSOLETE_DEAD.
1200 */
1201 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1202 return NULL;
1203 return dst;
1204}
1205
1206static void ipv4_send_dest_unreach(struct sk_buff *skb)
1207{
1208 struct ip_options opt;
1209 int res;
1210
1211 /* Recompile ip options since IPCB may not be valid anymore.
1212 * Also check we have a reasonable ipv4 header.
1213 */
1214 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1215 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1216 return;
1217
1218 memset(&opt, 0, sizeof(opt));
1219 if (ip_hdr(skb)->ihl > 5) {
1220 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1221 return;
1222 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1223
1224 rcu_read_lock();
1225 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL);
1226 rcu_read_unlock();
1227
1228 if (res)
1229 return;
1230 }
1231 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1232}
1233
1234static void ipv4_link_failure(struct sk_buff *skb)
1235{
1236 struct rtable *rt;
1237
1238 ipv4_send_dest_unreach(skb);
1239
1240 rt = skb_rtable(skb);
1241 if (rt)
1242 dst_set_expires(&rt->dst, 0);
1243}
1244
1245static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1246{
1247 pr_debug("%s: %pI4 -> %pI4, %s\n",
1248 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1249 skb->dev ? skb->dev->name : "?");
1250 kfree_skb(skb);
1251 WARN_ON(1);
1252 return 0;
1253}
1254
1255/*
1256 We do not cache source address of outgoing interface,
1257 because it is used only by IP RR, TS and SRR options,
1258 so that it out of fast path.
1259
1260 BTW remember: "addr" is allowed to be not aligned
1261 in IP options!
1262 */
1263
1264void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1265{
1266 __be32 src;
1267
1268 if (rt_is_output_route(rt))
1269 src = ip_hdr(skb)->saddr;
1270 else {
1271 struct fib_result res;
1272 struct iphdr *iph = ip_hdr(skb);
1273 struct flowi4 fl4 = {
1274 .daddr = iph->daddr,
1275 .saddr = iph->saddr,
1276 .flowi4_tos = RT_TOS(iph->tos),
1277 .flowi4_oif = rt->dst.dev->ifindex,
1278 .flowi4_iif = skb->dev->ifindex,
1279 .flowi4_mark = skb->mark,
1280 };
1281
1282 rcu_read_lock();
1283 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1284 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1285 else
1286 src = inet_select_addr(rt->dst.dev,
1287 rt_nexthop(rt, iph->daddr),
1288 RT_SCOPE_UNIVERSE);
1289 rcu_read_unlock();
1290 }
1291 memcpy(addr, &src, 4);
1292}
1293
1294#ifdef CONFIG_IP_ROUTE_CLASSID
1295static void set_class_tag(struct rtable *rt, u32 tag)
1296{
1297 if (!(rt->dst.tclassid & 0xFFFF))
1298 rt->dst.tclassid |= tag & 0xFFFF;
1299 if (!(rt->dst.tclassid & 0xFFFF0000))
1300 rt->dst.tclassid |= tag & 0xFFFF0000;
1301}
1302#endif
1303
1304static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1305{
1306 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1307 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1308 ip_rt_min_advmss);
1309
1310 return min(advmss, IPV4_MAX_PMTU - header_size);
1311}
1312
1313static unsigned int ipv4_mtu(const struct dst_entry *dst)
1314{
1315 const struct rtable *rt = (const struct rtable *) dst;
1316 unsigned int mtu = rt->rt_pmtu;
1317
1318 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1319 mtu = dst_metric_raw(dst, RTAX_MTU);
1320
1321 if (mtu)
1322 return mtu;
1323
1324 mtu = READ_ONCE(dst->dev->mtu);
1325
1326 if (unlikely(ip_mtu_locked(dst))) {
1327 if (rt->rt_uses_gateway && mtu > 576)
1328 mtu = 576;
1329 }
1330
1331 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1332
1333 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1334}
1335
1336static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1337{
1338 struct fnhe_hash_bucket *hash;
1339 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1340 u32 hval = fnhe_hashfun(daddr);
1341
1342 spin_lock_bh(&fnhe_lock);
1343
1344 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1345 lockdep_is_held(&fnhe_lock));
1346 hash += hval;
1347
1348 fnhe_p = &hash->chain;
1349 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1350 while (fnhe) {
1351 if (fnhe->fnhe_daddr == daddr) {
1352 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1353 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1354 /* set fnhe_daddr to 0 to ensure it won't bind with
1355 * new dsts in rt_bind_exception().
1356 */
1357 fnhe->fnhe_daddr = 0;
1358 fnhe_flush_routes(fnhe);
1359 kfree_rcu(fnhe, rcu);
1360 break;
1361 }
1362 fnhe_p = &fnhe->fnhe_next;
1363 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1364 lockdep_is_held(&fnhe_lock));
1365 }
1366
1367 spin_unlock_bh(&fnhe_lock);
1368}
1369
1370static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1371 __be32 daddr)
1372{
1373 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1374 struct fib_nh_exception *fnhe;
1375 u32 hval;
1376
1377 if (!hash)
1378 return NULL;
1379
1380 hval = fnhe_hashfun(daddr);
1381
1382 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1383 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1384 if (fnhe->fnhe_daddr == daddr) {
1385 if (fnhe->fnhe_expires &&
1386 time_after(jiffies, fnhe->fnhe_expires)) {
1387 ip_del_fnhe(nhc, daddr);
1388 break;
1389 }
1390 return fnhe;
1391 }
1392 }
1393 return NULL;
1394}
1395
1396/* MTU selection:
1397 * 1. mtu on route is locked - use it
1398 * 2. mtu from nexthop exception
1399 * 3. mtu from egress device
1400 */
1401
1402u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1403{
1404 struct fib_nh_common *nhc = res->nhc;
1405 struct net_device *dev = nhc->nhc_dev;
1406 struct fib_info *fi = res->fi;
1407 u32 mtu = 0;
1408
1409 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1410 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1411 mtu = fi->fib_mtu;
1412
1413 if (likely(!mtu)) {
1414 struct fib_nh_exception *fnhe;
1415
1416 fnhe = find_exception(nhc, daddr);
1417 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1418 mtu = fnhe->fnhe_pmtu;
1419 }
1420
1421 if (likely(!mtu))
1422 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1423
1424 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1425}
1426
1427static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1428 __be32 daddr, const bool do_cache)
1429{
1430 bool ret = false;
1431
1432 spin_lock_bh(&fnhe_lock);
1433
1434 if (daddr == fnhe->fnhe_daddr) {
1435 struct rtable __rcu **porig;
1436 struct rtable *orig;
1437 int genid = fnhe_genid(dev_net(rt->dst.dev));
1438
1439 if (rt_is_input_route(rt))
1440 porig = &fnhe->fnhe_rth_input;
1441 else
1442 porig = &fnhe->fnhe_rth_output;
1443 orig = rcu_dereference(*porig);
1444
1445 if (fnhe->fnhe_genid != genid) {
1446 fnhe->fnhe_genid = genid;
1447 fnhe->fnhe_gw = 0;
1448 fnhe->fnhe_pmtu = 0;
1449 fnhe->fnhe_expires = 0;
1450 fnhe->fnhe_mtu_locked = false;
1451 fnhe_flush_routes(fnhe);
1452 orig = NULL;
1453 }
1454 fill_route_from_fnhe(rt, fnhe);
1455 if (!rt->rt_gw4) {
1456 rt->rt_gw4 = daddr;
1457 rt->rt_gw_family = AF_INET;
1458 }
1459
1460 if (do_cache) {
1461 dst_hold(&rt->dst);
1462 rcu_assign_pointer(*porig, rt);
1463 if (orig) {
1464 dst_dev_put(&orig->dst);
1465 dst_release(&orig->dst);
1466 }
1467 ret = true;
1468 }
1469
1470 fnhe->fnhe_stamp = jiffies;
1471 }
1472 spin_unlock_bh(&fnhe_lock);
1473
1474 return ret;
1475}
1476
1477static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1478{
1479 struct rtable *orig, *prev, **p;
1480 bool ret = true;
1481
1482 if (rt_is_input_route(rt)) {
1483 p = (struct rtable **)&nhc->nhc_rth_input;
1484 } else {
1485 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1486 }
1487 orig = *p;
1488
1489 /* hold dst before doing cmpxchg() to avoid race condition
1490 * on this dst
1491 */
1492 dst_hold(&rt->dst);
1493 prev = cmpxchg(p, orig, rt);
1494 if (prev == orig) {
1495 if (orig) {
1496 rt_add_uncached_list(orig);
1497 dst_release(&orig->dst);
1498 }
1499 } else {
1500 dst_release(&rt->dst);
1501 ret = false;
1502 }
1503
1504 return ret;
1505}
1506
1507struct uncached_list {
1508 spinlock_t lock;
1509 struct list_head head;
1510};
1511
1512static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1513
1514void rt_add_uncached_list(struct rtable *rt)
1515{
1516 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1517
1518 rt->rt_uncached_list = ul;
1519
1520 spin_lock_bh(&ul->lock);
1521 list_add_tail(&rt->rt_uncached, &ul->head);
1522 spin_unlock_bh(&ul->lock);
1523}
1524
1525void rt_del_uncached_list(struct rtable *rt)
1526{
1527 if (!list_empty(&rt->rt_uncached)) {
1528 struct uncached_list *ul = rt->rt_uncached_list;
1529
1530 spin_lock_bh(&ul->lock);
1531 list_del(&rt->rt_uncached);
1532 spin_unlock_bh(&ul->lock);
1533 }
1534}
1535
1536static void ipv4_dst_destroy(struct dst_entry *dst)
1537{
1538 struct rtable *rt = (struct rtable *)dst;
1539
1540 ip_dst_metrics_put(dst);
1541 rt_del_uncached_list(rt);
1542}
1543
1544void rt_flush_dev(struct net_device *dev)
1545{
1546 struct rtable *rt;
1547 int cpu;
1548
1549 for_each_possible_cpu(cpu) {
1550 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1551
1552 spin_lock_bh(&ul->lock);
1553 list_for_each_entry(rt, &ul->head, rt_uncached) {
1554 if (rt->dst.dev != dev)
1555 continue;
1556 rt->dst.dev = blackhole_netdev;
1557 dev_hold(rt->dst.dev);
1558 dev_put(dev);
1559 }
1560 spin_unlock_bh(&ul->lock);
1561 }
1562}
1563
1564static bool rt_cache_valid(const struct rtable *rt)
1565{
1566 return rt &&
1567 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1568 !rt_is_expired(rt);
1569}
1570
1571static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1572 const struct fib_result *res,
1573 struct fib_nh_exception *fnhe,
1574 struct fib_info *fi, u16 type, u32 itag,
1575 const bool do_cache)
1576{
1577 bool cached = false;
1578
1579 if (fi) {
1580 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1581
1582 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1583 rt->rt_uses_gateway = 1;
1584 rt->rt_gw_family = nhc->nhc_gw_family;
1585 /* only INET and INET6 are supported */
1586 if (likely(nhc->nhc_gw_family == AF_INET))
1587 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1588 else
1589 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1590 }
1591
1592 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1593
1594#ifdef CONFIG_IP_ROUTE_CLASSID
1595 if (nhc->nhc_family == AF_INET) {
1596 struct fib_nh *nh;
1597
1598 nh = container_of(nhc, struct fib_nh, nh_common);
1599 rt->dst.tclassid = nh->nh_tclassid;
1600 }
1601#endif
1602 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1603 if (unlikely(fnhe))
1604 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1605 else if (do_cache)
1606 cached = rt_cache_route(nhc, rt);
1607 if (unlikely(!cached)) {
1608 /* Routes we intend to cache in nexthop exception or
1609 * FIB nexthop have the DST_NOCACHE bit clear.
1610 * However, if we are unsuccessful at storing this
1611 * route into the cache we really need to set it.
1612 */
1613 if (!rt->rt_gw4) {
1614 rt->rt_gw_family = AF_INET;
1615 rt->rt_gw4 = daddr;
1616 }
1617 rt_add_uncached_list(rt);
1618 }
1619 } else
1620 rt_add_uncached_list(rt);
1621
1622#ifdef CONFIG_IP_ROUTE_CLASSID
1623#ifdef CONFIG_IP_MULTIPLE_TABLES
1624 set_class_tag(rt, res->tclassid);
1625#endif
1626 set_class_tag(rt, itag);
1627#endif
1628}
1629
1630struct rtable *rt_dst_alloc(struct net_device *dev,
1631 unsigned int flags, u16 type,
1632 bool nopolicy, bool noxfrm)
1633{
1634 struct rtable *rt;
1635
1636 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1637 (nopolicy ? DST_NOPOLICY : 0) |
1638 (noxfrm ? DST_NOXFRM : 0));
1639
1640 if (rt) {
1641 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1642 rt->rt_flags = flags;
1643 rt->rt_type = type;
1644 rt->rt_is_input = 0;
1645 rt->rt_iif = 0;
1646 rt->rt_pmtu = 0;
1647 rt->rt_mtu_locked = 0;
1648 rt->rt_uses_gateway = 0;
1649 rt->rt_gw_family = 0;
1650 rt->rt_gw4 = 0;
1651 INIT_LIST_HEAD(&rt->rt_uncached);
1652
1653 rt->dst.output = ip_output;
1654 if (flags & RTCF_LOCAL)
1655 rt->dst.input = ip_local_deliver;
1656 }
1657
1658 return rt;
1659}
1660EXPORT_SYMBOL(rt_dst_alloc);
1661
1662struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1663{
1664 struct rtable *new_rt;
1665
1666 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1667 rt->dst.flags);
1668
1669 if (new_rt) {
1670 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1671 new_rt->rt_flags = rt->rt_flags;
1672 new_rt->rt_type = rt->rt_type;
1673 new_rt->rt_is_input = rt->rt_is_input;
1674 new_rt->rt_iif = rt->rt_iif;
1675 new_rt->rt_pmtu = rt->rt_pmtu;
1676 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1677 new_rt->rt_gw_family = rt->rt_gw_family;
1678 if (rt->rt_gw_family == AF_INET)
1679 new_rt->rt_gw4 = rt->rt_gw4;
1680 else if (rt->rt_gw_family == AF_INET6)
1681 new_rt->rt_gw6 = rt->rt_gw6;
1682 INIT_LIST_HEAD(&new_rt->rt_uncached);
1683
1684 new_rt->dst.input = rt->dst.input;
1685 new_rt->dst.output = rt->dst.output;
1686 new_rt->dst.error = rt->dst.error;
1687 new_rt->dst.lastuse = jiffies;
1688 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1689 }
1690 return new_rt;
1691}
1692EXPORT_SYMBOL(rt_dst_clone);
1693
1694/* called in rcu_read_lock() section */
1695int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1696 u8 tos, struct net_device *dev,
1697 struct in_device *in_dev, u32 *itag)
1698{
1699 int err;
1700
1701 /* Primary sanity checks. */
1702 if (!in_dev)
1703 return -EINVAL;
1704
1705 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1706 skb->protocol != htons(ETH_P_IP))
1707 return -EINVAL;
1708
1709 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1710 return -EINVAL;
1711
1712 if (ipv4_is_zeronet(saddr)) {
1713 if (!ipv4_is_local_multicast(daddr) &&
1714 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1715 return -EINVAL;
1716 } else {
1717 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1718 in_dev, itag);
1719 if (err < 0)
1720 return err;
1721 }
1722 return 0;
1723}
1724
1725/* called in rcu_read_lock() section */
1726static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1727 u8 tos, struct net_device *dev, int our)
1728{
1729 struct in_device *in_dev = __in_dev_get_rcu(dev);
1730 unsigned int flags = RTCF_MULTICAST;
1731 struct rtable *rth;
1732 u32 itag = 0;
1733 int err;
1734
1735 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1736 if (err)
1737 return err;
1738
1739 if (our)
1740 flags |= RTCF_LOCAL;
1741
1742 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1743 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
1744 if (!rth)
1745 return -ENOBUFS;
1746
1747#ifdef CONFIG_IP_ROUTE_CLASSID
1748 rth->dst.tclassid = itag;
1749#endif
1750 rth->dst.output = ip_rt_bug;
1751 rth->rt_is_input= 1;
1752
1753#ifdef CONFIG_IP_MROUTE
1754 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1755 rth->dst.input = ip_mr_input;
1756#endif
1757 RT_CACHE_STAT_INC(in_slow_mc);
1758
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 fnhe = find_exception(nhc, daddr);
1847 if (do_cache) {
1848 if (fnhe)
1849 rth = rcu_dereference(fnhe->fnhe_rth_input);
1850 else
1851 rth = rcu_dereference(nhc->nhc_rth_input);
1852 if (rt_cache_valid(rth)) {
1853 skb_dst_set_noref(skb, &rth->dst);
1854 goto out;
1855 }
1856 }
1857
1858 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1859 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1860 IN_DEV_CONF_GET(out_dev, NOXFRM));
1861 if (!rth) {
1862 err = -ENOBUFS;
1863 goto cleanup;
1864 }
1865
1866 rth->rt_is_input = 1;
1867 RT_CACHE_STAT_INC(in_slow_tot);
1868
1869 rth->dst.input = ip_forward;
1870
1871 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1872 do_cache);
1873 lwtunnel_set_redirect(&rth->dst);
1874 skb_dst_set(skb, &rth->dst);
1875out:
1876 err = 0;
1877 cleanup:
1878 return err;
1879}
1880
1881#ifdef CONFIG_IP_ROUTE_MULTIPATH
1882/* To make ICMP packets follow the right flow, the multipath hash is
1883 * calculated from the inner IP addresses.
1884 */
1885static void ip_multipath_l3_keys(const struct sk_buff *skb,
1886 struct flow_keys *hash_keys)
1887{
1888 const struct iphdr *outer_iph = ip_hdr(skb);
1889 const struct iphdr *key_iph = outer_iph;
1890 const struct iphdr *inner_iph;
1891 const struct icmphdr *icmph;
1892 struct iphdr _inner_iph;
1893 struct icmphdr _icmph;
1894
1895 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1896 goto out;
1897
1898 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1899 goto out;
1900
1901 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1902 &_icmph);
1903 if (!icmph)
1904 goto out;
1905
1906 if (!icmp_is_err(icmph->type))
1907 goto out;
1908
1909 inner_iph = skb_header_pointer(skb,
1910 outer_iph->ihl * 4 + sizeof(_icmph),
1911 sizeof(_inner_iph), &_inner_iph);
1912 if (!inner_iph)
1913 goto out;
1914
1915 key_iph = inner_iph;
1916out:
1917 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1918 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1919}
1920
1921/* if skb is set it will be used and fl4 can be NULL */
1922int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1923 const struct sk_buff *skb, struct flow_keys *flkeys)
1924{
1925 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
1926 struct flow_keys hash_keys;
1927 u32 mhash;
1928
1929 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1930 case 0:
1931 memset(&hash_keys, 0, sizeof(hash_keys));
1932 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1933 if (skb) {
1934 ip_multipath_l3_keys(skb, &hash_keys);
1935 } else {
1936 hash_keys.addrs.v4addrs.src = fl4->saddr;
1937 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1938 }
1939 break;
1940 case 1:
1941 /* skb is currently provided only when forwarding */
1942 if (skb) {
1943 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1944 struct flow_keys keys;
1945
1946 /* short-circuit if we already have L4 hash present */
1947 if (skb->l4_hash)
1948 return skb_get_hash_raw(skb) >> 1;
1949
1950 memset(&hash_keys, 0, sizeof(hash_keys));
1951
1952 if (!flkeys) {
1953 skb_flow_dissect_flow_keys(skb, &keys, flag);
1954 flkeys = &keys;
1955 }
1956
1957 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1958 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1959 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1960 hash_keys.ports.src = flkeys->ports.src;
1961 hash_keys.ports.dst = flkeys->ports.dst;
1962 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1963 } else {
1964 memset(&hash_keys, 0, sizeof(hash_keys));
1965 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1966 hash_keys.addrs.v4addrs.src = fl4->saddr;
1967 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1968 hash_keys.ports.src = fl4->fl4_sport;
1969 hash_keys.ports.dst = fl4->fl4_dport;
1970 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1971 }
1972 break;
1973 case 2:
1974 memset(&hash_keys, 0, sizeof(hash_keys));
1975 /* skb is currently provided only when forwarding */
1976 if (skb) {
1977 struct flow_keys keys;
1978
1979 skb_flow_dissect_flow_keys(skb, &keys, 0);
1980 /* Inner can be v4 or v6 */
1981 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1982 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1983 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1984 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1985 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1986 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1987 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1988 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1989 hash_keys.tags.flow_label = keys.tags.flow_label;
1990 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1991 } else {
1992 /* Same as case 0 */
1993 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1994 ip_multipath_l3_keys(skb, &hash_keys);
1995 }
1996 } else {
1997 /* Same as case 0 */
1998 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1999 hash_keys.addrs.v4addrs.src = fl4->saddr;
2000 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2001 }
2002 break;
2003 }
2004 mhash = flow_hash_from_keys(&hash_keys);
2005
2006 if (multipath_hash)
2007 mhash = jhash_2words(mhash, multipath_hash, 0);
2008
2009 return mhash >> 1;
2010}
2011#endif /* CONFIG_IP_ROUTE_MULTIPATH */
2012
2013static int ip_mkroute_input(struct sk_buff *skb,
2014 struct fib_result *res,
2015 struct in_device *in_dev,
2016 __be32 daddr, __be32 saddr, u32 tos,
2017 struct flow_keys *hkeys)
2018{
2019#ifdef CONFIG_IP_ROUTE_MULTIPATH
2020 if (res->fi && fib_info_num_path(res->fi) > 1) {
2021 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2022
2023 fib_select_multipath(res, h);
2024 }
2025#endif
2026
2027 /* create a routing cache entry */
2028 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2029}
2030
2031/* Implements all the saddr-related checks as ip_route_input_slow(),
2032 * assuming daddr is valid and the destination is not a local broadcast one.
2033 * Uses the provided hint instead of performing a route lookup.
2034 */
2035int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2036 u8 tos, struct net_device *dev,
2037 const struct sk_buff *hint)
2038{
2039 struct in_device *in_dev = __in_dev_get_rcu(dev);
2040 struct rtable *rt = skb_rtable(hint);
2041 struct net *net = dev_net(dev);
2042 int err = -EINVAL;
2043 u32 tag = 0;
2044
2045 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2046 goto martian_source;
2047
2048 if (ipv4_is_zeronet(saddr))
2049 goto martian_source;
2050
2051 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2052 goto martian_source;
2053
2054 if (rt->rt_type != RTN_LOCAL)
2055 goto skip_validate_source;
2056
2057 tos &= IPTOS_RT_MASK;
2058 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2059 if (err < 0)
2060 goto martian_source;
2061
2062skip_validate_source:
2063 skb_dst_copy(skb, hint);
2064 return 0;
2065
2066martian_source:
2067 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2068 return err;
2069}
2070
2071/*
2072 * NOTE. We drop all the packets that has local source
2073 * addresses, because every properly looped back packet
2074 * must have correct destination already attached by output routine.
2075 * Changes in the enforced policies must be applied also to
2076 * ip_route_use_hint().
2077 *
2078 * Such approach solves two big problems:
2079 * 1. Not simplex devices are handled properly.
2080 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2081 * called with rcu_read_lock()
2082 */
2083
2084static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2085 u8 tos, struct net_device *dev,
2086 struct fib_result *res)
2087{
2088 struct in_device *in_dev = __in_dev_get_rcu(dev);
2089 struct flow_keys *flkeys = NULL, _flkeys;
2090 struct net *net = dev_net(dev);
2091 struct ip_tunnel_info *tun_info;
2092 int err = -EINVAL;
2093 unsigned int flags = 0;
2094 u32 itag = 0;
2095 struct rtable *rth;
2096 struct flowi4 fl4;
2097 bool do_cache = true;
2098
2099 /* IP on this device is disabled. */
2100
2101 if (!in_dev)
2102 goto out;
2103
2104 /* Check for the most weird martians, which can be not detected
2105 by fib_lookup.
2106 */
2107
2108 tun_info = skb_tunnel_info(skb);
2109 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2110 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2111 else
2112 fl4.flowi4_tun_key.tun_id = 0;
2113 skb_dst_drop(skb);
2114
2115 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2116 goto martian_source;
2117
2118 res->fi = NULL;
2119 res->table = NULL;
2120 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2121 goto brd_input;
2122
2123 /* Accept zero addresses only to limited broadcast;
2124 * I even do not know to fix it or not. Waiting for complains :-)
2125 */
2126 if (ipv4_is_zeronet(saddr))
2127 goto martian_source;
2128
2129 if (ipv4_is_zeronet(daddr))
2130 goto martian_destination;
2131
2132 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2133 * and call it once if daddr or/and saddr are loopback addresses
2134 */
2135 if (ipv4_is_loopback(daddr)) {
2136 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2137 goto martian_destination;
2138 } else if (ipv4_is_loopback(saddr)) {
2139 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2140 goto martian_source;
2141 }
2142
2143 /*
2144 * Now we are ready to route packet.
2145 */
2146 fl4.flowi4_oif = 0;
2147 fl4.flowi4_iif = dev->ifindex;
2148 fl4.flowi4_mark = skb->mark;
2149 fl4.flowi4_tos = tos;
2150 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2151 fl4.flowi4_flags = 0;
2152 fl4.daddr = daddr;
2153 fl4.saddr = saddr;
2154 fl4.flowi4_uid = sock_net_uid(net, NULL);
2155 fl4.flowi4_multipath_hash = 0;
2156
2157 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2158 flkeys = &_flkeys;
2159 } else {
2160 fl4.flowi4_proto = 0;
2161 fl4.fl4_sport = 0;
2162 fl4.fl4_dport = 0;
2163 }
2164
2165 err = fib_lookup(net, &fl4, res, 0);
2166 if (err != 0) {
2167 if (!IN_DEV_FORWARD(in_dev))
2168 err = -EHOSTUNREACH;
2169 goto no_route;
2170 }
2171
2172 if (res->type == RTN_BROADCAST) {
2173 if (IN_DEV_BFORWARD(in_dev))
2174 goto make_route;
2175 /* not do cache if bc_forwarding is enabled */
2176 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))
2177 do_cache = false;
2178 goto brd_input;
2179 }
2180
2181 if (res->type == RTN_LOCAL) {
2182 err = fib_validate_source(skb, saddr, daddr, tos,
2183 0, dev, in_dev, &itag);
2184 if (err < 0)
2185 goto martian_source;
2186 goto local_input;
2187 }
2188
2189 if (!IN_DEV_FORWARD(in_dev)) {
2190 err = -EHOSTUNREACH;
2191 goto no_route;
2192 }
2193 if (res->type != RTN_UNICAST)
2194 goto martian_destination;
2195
2196make_route:
2197 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2198out: return err;
2199
2200brd_input:
2201 if (skb->protocol != htons(ETH_P_IP))
2202 goto e_inval;
2203
2204 if (!ipv4_is_zeronet(saddr)) {
2205 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2206 in_dev, &itag);
2207 if (err < 0)
2208 goto martian_source;
2209 }
2210 flags |= RTCF_BROADCAST;
2211 res->type = RTN_BROADCAST;
2212 RT_CACHE_STAT_INC(in_brd);
2213
2214local_input:
2215 do_cache &= res->fi && !itag;
2216 if (do_cache) {
2217 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2218
2219 rth = rcu_dereference(nhc->nhc_rth_input);
2220 if (rt_cache_valid(rth)) {
2221 skb_dst_set_noref(skb, &rth->dst);
2222 err = 0;
2223 goto out;
2224 }
2225 }
2226
2227 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2228 flags | RTCF_LOCAL, res->type,
2229 IN_DEV_CONF_GET(in_dev, NOPOLICY), false);
2230 if (!rth)
2231 goto e_nobufs;
2232
2233 rth->dst.output= ip_rt_bug;
2234#ifdef CONFIG_IP_ROUTE_CLASSID
2235 rth->dst.tclassid = itag;
2236#endif
2237 rth->rt_is_input = 1;
2238
2239 RT_CACHE_STAT_INC(in_slow_tot);
2240 if (res->type == RTN_UNREACHABLE) {
2241 rth->dst.input= ip_error;
2242 rth->dst.error= -err;
2243 rth->rt_flags &= ~RTCF_LOCAL;
2244 }
2245
2246 if (do_cache) {
2247 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2248
2249 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2250 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2251 WARN_ON(rth->dst.input == lwtunnel_input);
2252 rth->dst.lwtstate->orig_input = rth->dst.input;
2253 rth->dst.input = lwtunnel_input;
2254 }
2255
2256 if (unlikely(!rt_cache_route(nhc, rth)))
2257 rt_add_uncached_list(rth);
2258 }
2259 skb_dst_set(skb, &rth->dst);
2260 err = 0;
2261 goto out;
2262
2263no_route:
2264 RT_CACHE_STAT_INC(in_no_route);
2265 res->type = RTN_UNREACHABLE;
2266 res->fi = NULL;
2267 res->table = NULL;
2268 goto local_input;
2269
2270 /*
2271 * Do not cache martian addresses: they should be logged (RFC1812)
2272 */
2273martian_destination:
2274 RT_CACHE_STAT_INC(in_martian_dst);
2275#ifdef CONFIG_IP_ROUTE_VERBOSE
2276 if (IN_DEV_LOG_MARTIANS(in_dev))
2277 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2278 &daddr, &saddr, dev->name);
2279#endif
2280
2281e_inval:
2282 err = -EINVAL;
2283 goto out;
2284
2285e_nobufs:
2286 err = -ENOBUFS;
2287 goto out;
2288
2289martian_source:
2290 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2291 goto out;
2292}
2293
2294int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2295 u8 tos, struct net_device *dev)
2296{
2297 struct fib_result res;
2298 int err;
2299
2300 tos &= IPTOS_RT_MASK;
2301 rcu_read_lock();
2302 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2303 rcu_read_unlock();
2304
2305 return err;
2306}
2307EXPORT_SYMBOL(ip_route_input_noref);
2308
2309/* called with rcu_read_lock held */
2310int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2311 u8 tos, struct net_device *dev, struct fib_result *res)
2312{
2313 /* Multicast recognition logic is moved from route cache to here.
2314 The problem was that too many Ethernet cards have broken/missing
2315 hardware multicast filters :-( As result the host on multicasting
2316 network acquires a lot of useless route cache entries, sort of
2317 SDR messages from all the world. Now we try to get rid of them.
2318 Really, provided software IP multicast filter is organized
2319 reasonably (at least, hashed), it does not result in a slowdown
2320 comparing with route cache reject entries.
2321 Note, that multicast routers are not affected, because
2322 route cache entry is created eventually.
2323 */
2324 if (ipv4_is_multicast(daddr)) {
2325 struct in_device *in_dev = __in_dev_get_rcu(dev);
2326 int our = 0;
2327 int err = -EINVAL;
2328
2329 if (!in_dev)
2330 return err;
2331 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2332 ip_hdr(skb)->protocol);
2333
2334 /* check l3 master if no match yet */
2335 if (!our && netif_is_l3_slave(dev)) {
2336 struct in_device *l3_in_dev;
2337
2338 l3_in_dev = __in_dev_get_rcu(skb->dev);
2339 if (l3_in_dev)
2340 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2341 ip_hdr(skb)->protocol);
2342 }
2343
2344 if (our
2345#ifdef CONFIG_IP_MROUTE
2346 ||
2347 (!ipv4_is_local_multicast(daddr) &&
2348 IN_DEV_MFORWARD(in_dev))
2349#endif
2350 ) {
2351 err = ip_route_input_mc(skb, daddr, saddr,
2352 tos, dev, our);
2353 }
2354 return err;
2355 }
2356
2357 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2358}
2359
2360/* called with rcu_read_lock() */
2361static struct rtable *__mkroute_output(const struct fib_result *res,
2362 const struct flowi4 *fl4, int orig_oif,
2363 struct net_device *dev_out,
2364 unsigned int flags)
2365{
2366 struct fib_info *fi = res->fi;
2367 struct fib_nh_exception *fnhe;
2368 struct in_device *in_dev;
2369 u16 type = res->type;
2370 struct rtable *rth;
2371 bool do_cache;
2372
2373 in_dev = __in_dev_get_rcu(dev_out);
2374 if (!in_dev)
2375 return ERR_PTR(-EINVAL);
2376
2377 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2378 if (ipv4_is_loopback(fl4->saddr) &&
2379 !(dev_out->flags & IFF_LOOPBACK) &&
2380 !netif_is_l3_master(dev_out))
2381 return ERR_PTR(-EINVAL);
2382
2383 if (ipv4_is_lbcast(fl4->daddr))
2384 type = RTN_BROADCAST;
2385 else if (ipv4_is_multicast(fl4->daddr))
2386 type = RTN_MULTICAST;
2387 else if (ipv4_is_zeronet(fl4->daddr))
2388 return ERR_PTR(-EINVAL);
2389
2390 if (dev_out->flags & IFF_LOOPBACK)
2391 flags |= RTCF_LOCAL;
2392
2393 do_cache = true;
2394 if (type == RTN_BROADCAST) {
2395 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2396 fi = NULL;
2397 } else if (type == RTN_MULTICAST) {
2398 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2399 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2400 fl4->flowi4_proto))
2401 flags &= ~RTCF_LOCAL;
2402 else
2403 do_cache = false;
2404 /* If multicast route do not exist use
2405 * default one, but do not gateway in this case.
2406 * Yes, it is hack.
2407 */
2408 if (fi && res->prefixlen < 4)
2409 fi = NULL;
2410 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2411 (orig_oif != dev_out->ifindex)) {
2412 /* For local routes that require a particular output interface
2413 * we do not want to cache the result. Caching the result
2414 * causes incorrect behaviour when there are multiple source
2415 * addresses on the interface, the end result being that if the
2416 * intended recipient is waiting on that interface for the
2417 * packet he won't receive it because it will be delivered on
2418 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2419 * be set to the loopback interface as well.
2420 */
2421 do_cache = false;
2422 }
2423
2424 fnhe = NULL;
2425 do_cache &= fi != NULL;
2426 if (fi) {
2427 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2428 struct rtable __rcu **prth;
2429
2430 fnhe = find_exception(nhc, fl4->daddr);
2431 if (!do_cache)
2432 goto add;
2433 if (fnhe) {
2434 prth = &fnhe->fnhe_rth_output;
2435 } else {
2436 if (unlikely(fl4->flowi4_flags &
2437 FLOWI_FLAG_KNOWN_NH &&
2438 !(nhc->nhc_gw_family &&
2439 nhc->nhc_scope == RT_SCOPE_LINK))) {
2440 do_cache = false;
2441 goto add;
2442 }
2443 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2444 }
2445 rth = rcu_dereference(*prth);
2446 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2447 return rth;
2448 }
2449
2450add:
2451 rth = rt_dst_alloc(dev_out, flags, type,
2452 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2453 IN_DEV_CONF_GET(in_dev, NOXFRM));
2454 if (!rth)
2455 return ERR_PTR(-ENOBUFS);
2456
2457 rth->rt_iif = orig_oif;
2458
2459 RT_CACHE_STAT_INC(out_slow_tot);
2460
2461 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2462 if (flags & RTCF_LOCAL &&
2463 !(dev_out->flags & IFF_LOOPBACK)) {
2464 rth->dst.output = ip_mc_output;
2465 RT_CACHE_STAT_INC(out_slow_mc);
2466 }
2467#ifdef CONFIG_IP_MROUTE
2468 if (type == RTN_MULTICAST) {
2469 if (IN_DEV_MFORWARD(in_dev) &&
2470 !ipv4_is_local_multicast(fl4->daddr)) {
2471 rth->dst.input = ip_mr_input;
2472 rth->dst.output = ip_mc_output;
2473 }
2474 }
2475#endif
2476 }
2477
2478 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2479 lwtunnel_set_redirect(&rth->dst);
2480
2481 return rth;
2482}
2483
2484/*
2485 * Major route resolver routine.
2486 */
2487
2488struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2489 const struct sk_buff *skb)
2490{
2491 __u8 tos = RT_FL_TOS(fl4);
2492 struct fib_result res = {
2493 .type = RTN_UNSPEC,
2494 .fi = NULL,
2495 .table = NULL,
2496 .tclassid = 0,
2497 };
2498 struct rtable *rth;
2499
2500 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2501 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2502 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2503 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2504
2505 rcu_read_lock();
2506 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2507 rcu_read_unlock();
2508
2509 return rth;
2510}
2511EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2512
2513struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2514 struct fib_result *res,
2515 const struct sk_buff *skb)
2516{
2517 struct net_device *dev_out = NULL;
2518 int orig_oif = fl4->flowi4_oif;
2519 unsigned int flags = 0;
2520 struct rtable *rth;
2521 int err;
2522
2523 if (fl4->saddr) {
2524 if (ipv4_is_multicast(fl4->saddr) ||
2525 ipv4_is_lbcast(fl4->saddr) ||
2526 ipv4_is_zeronet(fl4->saddr)) {
2527 rth = ERR_PTR(-EINVAL);
2528 goto out;
2529 }
2530
2531 rth = ERR_PTR(-ENETUNREACH);
2532
2533 /* I removed check for oif == dev_out->oif here.
2534 It was wrong for two reasons:
2535 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2536 is assigned to multiple interfaces.
2537 2. Moreover, we are allowed to send packets with saddr
2538 of another iface. --ANK
2539 */
2540
2541 if (fl4->flowi4_oif == 0 &&
2542 (ipv4_is_multicast(fl4->daddr) ||
2543 ipv4_is_lbcast(fl4->daddr))) {
2544 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2545 dev_out = __ip_dev_find(net, fl4->saddr, false);
2546 if (!dev_out)
2547 goto out;
2548
2549 /* Special hack: user can direct multicasts
2550 and limited broadcast via necessary interface
2551 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2552 This hack is not just for fun, it allows
2553 vic,vat and friends to work.
2554 They bind socket to loopback, set ttl to zero
2555 and expect that it will work.
2556 From the viewpoint of routing cache they are broken,
2557 because we are not allowed to build multicast path
2558 with loopback source addr (look, routing cache
2559 cannot know, that ttl is zero, so that packet
2560 will not leave this host and route is valid).
2561 Luckily, this hack is good workaround.
2562 */
2563
2564 fl4->flowi4_oif = dev_out->ifindex;
2565 goto make_route;
2566 }
2567
2568 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2569 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2570 if (!__ip_dev_find(net, fl4->saddr, false))
2571 goto out;
2572 }
2573 }
2574
2575
2576 if (fl4->flowi4_oif) {
2577 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2578 rth = ERR_PTR(-ENODEV);
2579 if (!dev_out)
2580 goto out;
2581
2582 /* RACE: Check return value of inet_select_addr instead. */
2583 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2584 rth = ERR_PTR(-ENETUNREACH);
2585 goto out;
2586 }
2587 if (ipv4_is_local_multicast(fl4->daddr) ||
2588 ipv4_is_lbcast(fl4->daddr) ||
2589 fl4->flowi4_proto == IPPROTO_IGMP) {
2590 if (!fl4->saddr)
2591 fl4->saddr = inet_select_addr(dev_out, 0,
2592 RT_SCOPE_LINK);
2593 goto make_route;
2594 }
2595 if (!fl4->saddr) {
2596 if (ipv4_is_multicast(fl4->daddr))
2597 fl4->saddr = inet_select_addr(dev_out, 0,
2598 fl4->flowi4_scope);
2599 else if (!fl4->daddr)
2600 fl4->saddr = inet_select_addr(dev_out, 0,
2601 RT_SCOPE_HOST);
2602 }
2603 }
2604
2605 if (!fl4->daddr) {
2606 fl4->daddr = fl4->saddr;
2607 if (!fl4->daddr)
2608 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2609 dev_out = net->loopback_dev;
2610 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2611 res->type = RTN_LOCAL;
2612 flags |= RTCF_LOCAL;
2613 goto make_route;
2614 }
2615
2616 err = fib_lookup(net, fl4, res, 0);
2617 if (err) {
2618 res->fi = NULL;
2619 res->table = NULL;
2620 if (fl4->flowi4_oif &&
2621 (ipv4_is_multicast(fl4->daddr) ||
2622 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2623 /* Apparently, routing tables are wrong. Assume,
2624 that the destination is on link.
2625
2626 WHY? DW.
2627 Because we are allowed to send to iface
2628 even if it has NO routes and NO assigned
2629 addresses. When oif is specified, routing
2630 tables are looked up with only one purpose:
2631 to catch if destination is gatewayed, rather than
2632 direct. Moreover, if MSG_DONTROUTE is set,
2633 we send packet, ignoring both routing tables
2634 and ifaddr state. --ANK
2635
2636
2637 We could make it even if oif is unknown,
2638 likely IPv6, but we do not.
2639 */
2640
2641 if (fl4->saddr == 0)
2642 fl4->saddr = inet_select_addr(dev_out, 0,
2643 RT_SCOPE_LINK);
2644 res->type = RTN_UNICAST;
2645 goto make_route;
2646 }
2647 rth = ERR_PTR(err);
2648 goto out;
2649 }
2650
2651 if (res->type == RTN_LOCAL) {
2652 if (!fl4->saddr) {
2653 if (res->fi->fib_prefsrc)
2654 fl4->saddr = res->fi->fib_prefsrc;
2655 else
2656 fl4->saddr = fl4->daddr;
2657 }
2658
2659 /* L3 master device is the loopback for that domain */
2660 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2661 net->loopback_dev;
2662
2663 /* make sure orig_oif points to fib result device even
2664 * though packet rx/tx happens over loopback or l3mdev
2665 */
2666 orig_oif = FIB_RES_OIF(*res);
2667
2668 fl4->flowi4_oif = dev_out->ifindex;
2669 flags |= RTCF_LOCAL;
2670 goto make_route;
2671 }
2672
2673 fib_select_path(net, res, fl4, skb);
2674
2675 dev_out = FIB_RES_DEV(*res);
2676
2677make_route:
2678 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2679
2680out:
2681 return rth;
2682}
2683
2684static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2685{
2686 return NULL;
2687}
2688
2689static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2690{
2691 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2692
2693 return mtu ? : dst->dev->mtu;
2694}
2695
2696static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2697 struct sk_buff *skb, u32 mtu,
2698 bool confirm_neigh)
2699{
2700}
2701
2702static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2703 struct sk_buff *skb)
2704{
2705}
2706
2707static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2708 unsigned long old)
2709{
2710 return NULL;
2711}
2712
2713static struct dst_ops ipv4_dst_blackhole_ops = {
2714 .family = AF_INET,
2715 .check = ipv4_blackhole_dst_check,
2716 .mtu = ipv4_blackhole_mtu,
2717 .default_advmss = ipv4_default_advmss,
2718 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2719 .redirect = ipv4_rt_blackhole_redirect,
2720 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2721 .neigh_lookup = ipv4_neigh_lookup,
2722};
2723
2724struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2725{
2726 struct rtable *ort = (struct rtable *) dst_orig;
2727 struct rtable *rt;
2728
2729 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2730 if (rt) {
2731 struct dst_entry *new = &rt->dst;
2732
2733 new->__use = 1;
2734 new->input = dst_discard;
2735 new->output = dst_discard_out;
2736
2737 new->dev = net->loopback_dev;
2738 if (new->dev)
2739 dev_hold(new->dev);
2740
2741 rt->rt_is_input = ort->rt_is_input;
2742 rt->rt_iif = ort->rt_iif;
2743 rt->rt_pmtu = ort->rt_pmtu;
2744 rt->rt_mtu_locked = ort->rt_mtu_locked;
2745
2746 rt->rt_genid = rt_genid_ipv4(net);
2747 rt->rt_flags = ort->rt_flags;
2748 rt->rt_type = ort->rt_type;
2749 rt->rt_uses_gateway = ort->rt_uses_gateway;
2750 rt->rt_gw_family = ort->rt_gw_family;
2751 if (rt->rt_gw_family == AF_INET)
2752 rt->rt_gw4 = ort->rt_gw4;
2753 else if (rt->rt_gw_family == AF_INET6)
2754 rt->rt_gw6 = ort->rt_gw6;
2755
2756 INIT_LIST_HEAD(&rt->rt_uncached);
2757 }
2758
2759 dst_release(dst_orig);
2760
2761 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2762}
2763
2764struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2765 const struct sock *sk)
2766{
2767 struct rtable *rt = __ip_route_output_key(net, flp4);
2768
2769 if (IS_ERR(rt))
2770 return rt;
2771
2772 if (flp4->flowi4_proto)
2773 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2774 flowi4_to_flowi(flp4),
2775 sk, 0);
2776
2777 return rt;
2778}
2779EXPORT_SYMBOL_GPL(ip_route_output_flow);
2780
2781struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
2782 struct net_device *dev,
2783 struct net *net, __be32 *saddr,
2784 const struct ip_tunnel_info *info,
2785 u8 protocol, bool use_cache)
2786{
2787#ifdef CONFIG_DST_CACHE
2788 struct dst_cache *dst_cache;
2789#endif
2790 struct rtable *rt = NULL;
2791 struct flowi4 fl4;
2792 __u8 tos;
2793
2794#ifdef CONFIG_DST_CACHE
2795 dst_cache = (struct dst_cache *)&info->dst_cache;
2796 if (use_cache) {
2797 rt = dst_cache_get_ip4(dst_cache, saddr);
2798 if (rt)
2799 return rt;
2800 }
2801#endif
2802 memset(&fl4, 0, sizeof(fl4));
2803 fl4.flowi4_mark = skb->mark;
2804 fl4.flowi4_proto = protocol;
2805 fl4.daddr = info->key.u.ipv4.dst;
2806 fl4.saddr = info->key.u.ipv4.src;
2807 tos = info->key.tos;
2808 fl4.flowi4_tos = RT_TOS(tos);
2809
2810 rt = ip_route_output_key(net, &fl4);
2811 if (IS_ERR(rt)) {
2812 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr);
2813 return ERR_PTR(-ENETUNREACH);
2814 }
2815 if (rt->dst.dev == dev) { /* is this necessary? */
2816 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr);
2817 ip_rt_put(rt);
2818 return ERR_PTR(-ELOOP);
2819 }
2820#ifdef CONFIG_DST_CACHE
2821 if (use_cache)
2822 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
2823#endif
2824 *saddr = fl4.saddr;
2825 return rt;
2826}
2827EXPORT_SYMBOL_GPL(ip_route_output_tunnel);
2828
2829/* called with rcu_read_lock held */
2830static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2831 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2832 struct sk_buff *skb, u32 portid, u32 seq,
2833 unsigned int flags)
2834{
2835 struct rtmsg *r;
2836 struct nlmsghdr *nlh;
2837 unsigned long expires = 0;
2838 u32 error;
2839 u32 metrics[RTAX_MAX];
2840
2841 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2842 if (!nlh)
2843 return -EMSGSIZE;
2844
2845 r = nlmsg_data(nlh);
2846 r->rtm_family = AF_INET;
2847 r->rtm_dst_len = 32;
2848 r->rtm_src_len = 0;
2849 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2850 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2851 if (nla_put_u32(skb, RTA_TABLE, table_id))
2852 goto nla_put_failure;
2853 r->rtm_type = rt->rt_type;
2854 r->rtm_scope = RT_SCOPE_UNIVERSE;
2855 r->rtm_protocol = RTPROT_UNSPEC;
2856 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2857 if (rt->rt_flags & RTCF_NOTIFY)
2858 r->rtm_flags |= RTM_F_NOTIFY;
2859 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2860 r->rtm_flags |= RTCF_DOREDIRECT;
2861
2862 if (nla_put_in_addr(skb, RTA_DST, dst))
2863 goto nla_put_failure;
2864 if (src) {
2865 r->rtm_src_len = 32;
2866 if (nla_put_in_addr(skb, RTA_SRC, src))
2867 goto nla_put_failure;
2868 }
2869 if (rt->dst.dev &&
2870 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2871 goto nla_put_failure;
2872#ifdef CONFIG_IP_ROUTE_CLASSID
2873 if (rt->dst.tclassid &&
2874 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2875 goto nla_put_failure;
2876#endif
2877 if (fl4 && !rt_is_input_route(rt) &&
2878 fl4->saddr != src) {
2879 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2880 goto nla_put_failure;
2881 }
2882 if (rt->rt_uses_gateway) {
2883 if (rt->rt_gw_family == AF_INET &&
2884 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2885 goto nla_put_failure;
2886 } else if (rt->rt_gw_family == AF_INET6) {
2887 int alen = sizeof(struct in6_addr);
2888 struct nlattr *nla;
2889 struct rtvia *via;
2890
2891 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2892 if (!nla)
2893 goto nla_put_failure;
2894
2895 via = nla_data(nla);
2896 via->rtvia_family = AF_INET6;
2897 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2898 }
2899 }
2900
2901 expires = rt->dst.expires;
2902 if (expires) {
2903 unsigned long now = jiffies;
2904
2905 if (time_before(now, expires))
2906 expires -= now;
2907 else
2908 expires = 0;
2909 }
2910
2911 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2912 if (rt->rt_pmtu && expires)
2913 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2914 if (rt->rt_mtu_locked && expires)
2915 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2916 if (rtnetlink_put_metrics(skb, metrics) < 0)
2917 goto nla_put_failure;
2918
2919 if (fl4) {
2920 if (fl4->flowi4_mark &&
2921 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2922 goto nla_put_failure;
2923
2924 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2925 nla_put_u32(skb, RTA_UID,
2926 from_kuid_munged(current_user_ns(),
2927 fl4->flowi4_uid)))
2928 goto nla_put_failure;
2929
2930 if (rt_is_input_route(rt)) {
2931#ifdef CONFIG_IP_MROUTE
2932 if (ipv4_is_multicast(dst) &&
2933 !ipv4_is_local_multicast(dst) &&
2934 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2935 int err = ipmr_get_route(net, skb,
2936 fl4->saddr, fl4->daddr,
2937 r, portid);
2938
2939 if (err <= 0) {
2940 if (err == 0)
2941 return 0;
2942 goto nla_put_failure;
2943 }
2944 } else
2945#endif
2946 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
2947 goto nla_put_failure;
2948 }
2949 }
2950
2951 error = rt->dst.error;
2952
2953 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2954 goto nla_put_failure;
2955
2956 nlmsg_end(skb, nlh);
2957 return 0;
2958
2959nla_put_failure:
2960 nlmsg_cancel(skb, nlh);
2961 return -EMSGSIZE;
2962}
2963
2964static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
2965 struct netlink_callback *cb, u32 table_id,
2966 struct fnhe_hash_bucket *bucket, int genid,
2967 int *fa_index, int fa_start, unsigned int flags)
2968{
2969 int i;
2970
2971 for (i = 0; i < FNHE_HASH_SIZE; i++) {
2972 struct fib_nh_exception *fnhe;
2973
2974 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
2975 fnhe = rcu_dereference(fnhe->fnhe_next)) {
2976 struct rtable *rt;
2977 int err;
2978
2979 if (*fa_index < fa_start)
2980 goto next;
2981
2982 if (fnhe->fnhe_genid != genid)
2983 goto next;
2984
2985 if (fnhe->fnhe_expires &&
2986 time_after(jiffies, fnhe->fnhe_expires))
2987 goto next;
2988
2989 rt = rcu_dereference(fnhe->fnhe_rth_input);
2990 if (!rt)
2991 rt = rcu_dereference(fnhe->fnhe_rth_output);
2992 if (!rt)
2993 goto next;
2994
2995 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
2996 table_id, NULL, skb,
2997 NETLINK_CB(cb->skb).portid,
2998 cb->nlh->nlmsg_seq, flags);
2999 if (err)
3000 return err;
3001next:
3002 (*fa_index)++;
3003 }
3004 }
3005
3006 return 0;
3007}
3008
3009int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3010 u32 table_id, struct fib_info *fi,
3011 int *fa_index, int fa_start, unsigned int flags)
3012{
3013 struct net *net = sock_net(cb->skb->sk);
3014 int nhsel, genid = fnhe_genid(net);
3015
3016 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3017 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3018 struct fnhe_hash_bucket *bucket;
3019 int err;
3020
3021 if (nhc->nhc_flags & RTNH_F_DEAD)
3022 continue;
3023
3024 rcu_read_lock();
3025 bucket = rcu_dereference(nhc->nhc_exceptions);
3026 err = 0;
3027 if (bucket)
3028 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3029 genid, fa_index, fa_start,
3030 flags);
3031 rcu_read_unlock();
3032 if (err)
3033 return err;
3034 }
3035
3036 return 0;
3037}
3038
3039static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3040 u8 ip_proto, __be16 sport,
3041 __be16 dport)
3042{
3043 struct sk_buff *skb;
3044 struct iphdr *iph;
3045
3046 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3047 if (!skb)
3048 return NULL;
3049
3050 /* Reserve room for dummy headers, this skb can pass
3051 * through good chunk of routing engine.
3052 */
3053 skb_reset_mac_header(skb);
3054 skb_reset_network_header(skb);
3055 skb->protocol = htons(ETH_P_IP);
3056 iph = skb_put(skb, sizeof(struct iphdr));
3057 iph->protocol = ip_proto;
3058 iph->saddr = src;
3059 iph->daddr = dst;
3060 iph->version = 0x4;
3061 iph->frag_off = 0;
3062 iph->ihl = 0x5;
3063 skb_set_transport_header(skb, skb->len);
3064
3065 switch (iph->protocol) {
3066 case IPPROTO_UDP: {
3067 struct udphdr *udph;
3068
3069 udph = skb_put_zero(skb, sizeof(struct udphdr));
3070 udph->source = sport;
3071 udph->dest = dport;
3072 udph->len = sizeof(struct udphdr);
3073 udph->check = 0;
3074 break;
3075 }
3076 case IPPROTO_TCP: {
3077 struct tcphdr *tcph;
3078
3079 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3080 tcph->source = sport;
3081 tcph->dest = dport;
3082 tcph->doff = sizeof(struct tcphdr) / 4;
3083 tcph->rst = 1;
3084 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3085 src, dst, 0);
3086 break;
3087 }
3088 case IPPROTO_ICMP: {
3089 struct icmphdr *icmph;
3090
3091 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3092 icmph->type = ICMP_ECHO;
3093 icmph->code = 0;
3094 }
3095 }
3096
3097 return skb;
3098}
3099
3100static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3101 const struct nlmsghdr *nlh,
3102 struct nlattr **tb,
3103 struct netlink_ext_ack *extack)
3104{
3105 struct rtmsg *rtm;
3106 int i, err;
3107
3108 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3109 NL_SET_ERR_MSG(extack,
3110 "ipv4: Invalid header for route get request");
3111 return -EINVAL;
3112 }
3113
3114 if (!netlink_strict_get_check(skb))
3115 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3116 rtm_ipv4_policy, extack);
3117
3118 rtm = nlmsg_data(nlh);
3119 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3120 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3121 rtm->rtm_table || rtm->rtm_protocol ||
3122 rtm->rtm_scope || rtm->rtm_type) {
3123 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3124 return -EINVAL;
3125 }
3126
3127 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3128 RTM_F_LOOKUP_TABLE |
3129 RTM_F_FIB_MATCH)) {
3130 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3131 return -EINVAL;
3132 }
3133
3134 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3135 rtm_ipv4_policy, extack);
3136 if (err)
3137 return err;
3138
3139 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3140 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3141 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3142 return -EINVAL;
3143 }
3144
3145 for (i = 0; i <= RTA_MAX; i++) {
3146 if (!tb[i])
3147 continue;
3148
3149 switch (i) {
3150 case RTA_IIF:
3151 case RTA_OIF:
3152 case RTA_SRC:
3153 case RTA_DST:
3154 case RTA_IP_PROTO:
3155 case RTA_SPORT:
3156 case RTA_DPORT:
3157 case RTA_MARK:
3158 case RTA_UID:
3159 break;
3160 default:
3161 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3162 return -EINVAL;
3163 }
3164 }
3165
3166 return 0;
3167}
3168
3169static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3170 struct netlink_ext_ack *extack)
3171{
3172 struct net *net = sock_net(in_skb->sk);
3173 struct nlattr *tb[RTA_MAX+1];
3174 u32 table_id = RT_TABLE_MAIN;
3175 __be16 sport = 0, dport = 0;
3176 struct fib_result res = {};
3177 u8 ip_proto = IPPROTO_UDP;
3178 struct rtable *rt = NULL;
3179 struct sk_buff *skb;
3180 struct rtmsg *rtm;
3181 struct flowi4 fl4 = {};
3182 __be32 dst = 0;
3183 __be32 src = 0;
3184 kuid_t uid;
3185 u32 iif;
3186 int err;
3187 int mark;
3188
3189 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3190 if (err < 0)
3191 return err;
3192
3193 rtm = nlmsg_data(nlh);
3194 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3195 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3196 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3197 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3198 if (tb[RTA_UID])
3199 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3200 else
3201 uid = (iif ? INVALID_UID : current_uid());
3202
3203 if (tb[RTA_IP_PROTO]) {
3204 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3205 &ip_proto, AF_INET, extack);
3206 if (err)
3207 return err;
3208 }
3209
3210 if (tb[RTA_SPORT])
3211 sport = nla_get_be16(tb[RTA_SPORT]);
3212
3213 if (tb[RTA_DPORT])
3214 dport = nla_get_be16(tb[RTA_DPORT]);
3215
3216 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3217 if (!skb)
3218 return -ENOBUFS;
3219
3220 fl4.daddr = dst;
3221 fl4.saddr = src;
3222 fl4.flowi4_tos = rtm->rtm_tos;
3223 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3224 fl4.flowi4_mark = mark;
3225 fl4.flowi4_uid = uid;
3226 if (sport)
3227 fl4.fl4_sport = sport;
3228 if (dport)
3229 fl4.fl4_dport = dport;
3230 fl4.flowi4_proto = ip_proto;
3231
3232 rcu_read_lock();
3233
3234 if (iif) {
3235 struct net_device *dev;
3236
3237 dev = dev_get_by_index_rcu(net, iif);
3238 if (!dev) {
3239 err = -ENODEV;
3240 goto errout_rcu;
3241 }
3242
3243 fl4.flowi4_iif = iif; /* for rt_fill_info */
3244 skb->dev = dev;
3245 skb->mark = mark;
3246 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
3247 dev, &res);
3248
3249 rt = skb_rtable(skb);
3250 if (err == 0 && rt->dst.error)
3251 err = -rt->dst.error;
3252 } else {
3253 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3254 skb->dev = net->loopback_dev;
3255 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3256 err = 0;
3257 if (IS_ERR(rt))
3258 err = PTR_ERR(rt);
3259 else
3260 skb_dst_set(skb, &rt->dst);
3261 }
3262
3263 if (err)
3264 goto errout_rcu;
3265
3266 if (rtm->rtm_flags & RTM_F_NOTIFY)
3267 rt->rt_flags |= RTCF_NOTIFY;
3268
3269 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3270 table_id = res.table ? res.table->tb_id : 0;
3271
3272 /* reset skb for netlink reply msg */
3273 skb_trim(skb, 0);
3274 skb_reset_network_header(skb);
3275 skb_reset_transport_header(skb);
3276 skb_reset_mac_header(skb);
3277
3278 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3279 struct fib_rt_info fri;
3280
3281 if (!res.fi) {
3282 err = fib_props[res.type].error;
3283 if (!err)
3284 err = -EHOSTUNREACH;
3285 goto errout_rcu;
3286 }
3287 fri.fi = res.fi;
3288 fri.tb_id = table_id;
3289 fri.dst = res.prefix;
3290 fri.dst_len = res.prefixlen;
3291 fri.tos = fl4.flowi4_tos;
3292 fri.type = rt->rt_type;
3293 fri.offload = 0;
3294 fri.trap = 0;
3295 if (res.fa_head) {
3296 struct fib_alias *fa;
3297
3298 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3299 u8 slen = 32 - fri.dst_len;
3300
3301 if (fa->fa_slen == slen &&
3302 fa->tb_id == fri.tb_id &&
3303 fa->fa_tos == fri.tos &&
3304 fa->fa_info == res.fi &&
3305 fa->fa_type == fri.type) {
3306 fri.offload = fa->offload;
3307 fri.trap = fa->trap;
3308 break;
3309 }
3310 }
3311 }
3312 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3313 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3314 } else {
3315 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3316 NETLINK_CB(in_skb).portid,
3317 nlh->nlmsg_seq, 0);
3318 }
3319 if (err < 0)
3320 goto errout_rcu;
3321
3322 rcu_read_unlock();
3323
3324 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3325
3326errout_free:
3327 return err;
3328errout_rcu:
3329 rcu_read_unlock();
3330 kfree_skb(skb);
3331 goto errout_free;
3332}
3333
3334void ip_rt_multicast_event(struct in_device *in_dev)
3335{
3336 rt_cache_flush(dev_net(in_dev->dev));
3337}
3338
3339#ifdef CONFIG_SYSCTL
3340static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3341static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3342static int ip_rt_gc_elasticity __read_mostly = 8;
3343static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3344
3345static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3346 void *buffer, size_t *lenp, loff_t *ppos)
3347{
3348 struct net *net = (struct net *)__ctl->extra1;
3349
3350 if (write) {
3351 rt_cache_flush(net);
3352 fnhe_genid_bump(net);
3353 return 0;
3354 }
3355
3356 return -EINVAL;
3357}
3358
3359static struct ctl_table ipv4_route_table[] = {
3360 {
3361 .procname = "gc_thresh",
3362 .data = &ipv4_dst_ops.gc_thresh,
3363 .maxlen = sizeof(int),
3364 .mode = 0644,
3365 .proc_handler = proc_dointvec,
3366 },
3367 {
3368 .procname = "max_size",
3369 .data = &ip_rt_max_size,
3370 .maxlen = sizeof(int),
3371 .mode = 0644,
3372 .proc_handler = proc_dointvec,
3373 },
3374 {
3375 /* Deprecated. Use gc_min_interval_ms */
3376
3377 .procname = "gc_min_interval",
3378 .data = &ip_rt_gc_min_interval,
3379 .maxlen = sizeof(int),
3380 .mode = 0644,
3381 .proc_handler = proc_dointvec_jiffies,
3382 },
3383 {
3384 .procname = "gc_min_interval_ms",
3385 .data = &ip_rt_gc_min_interval,
3386 .maxlen = sizeof(int),
3387 .mode = 0644,
3388 .proc_handler = proc_dointvec_ms_jiffies,
3389 },
3390 {
3391 .procname = "gc_timeout",
3392 .data = &ip_rt_gc_timeout,
3393 .maxlen = sizeof(int),
3394 .mode = 0644,
3395 .proc_handler = proc_dointvec_jiffies,
3396 },
3397 {
3398 .procname = "gc_interval",
3399 .data = &ip_rt_gc_interval,
3400 .maxlen = sizeof(int),
3401 .mode = 0644,
3402 .proc_handler = proc_dointvec_jiffies,
3403 },
3404 {
3405 .procname = "redirect_load",
3406 .data = &ip_rt_redirect_load,
3407 .maxlen = sizeof(int),
3408 .mode = 0644,
3409 .proc_handler = proc_dointvec,
3410 },
3411 {
3412 .procname = "redirect_number",
3413 .data = &ip_rt_redirect_number,
3414 .maxlen = sizeof(int),
3415 .mode = 0644,
3416 .proc_handler = proc_dointvec,
3417 },
3418 {
3419 .procname = "redirect_silence",
3420 .data = &ip_rt_redirect_silence,
3421 .maxlen = sizeof(int),
3422 .mode = 0644,
3423 .proc_handler = proc_dointvec,
3424 },
3425 {
3426 .procname = "error_cost",
3427 .data = &ip_rt_error_cost,
3428 .maxlen = sizeof(int),
3429 .mode = 0644,
3430 .proc_handler = proc_dointvec,
3431 },
3432 {
3433 .procname = "error_burst",
3434 .data = &ip_rt_error_burst,
3435 .maxlen = sizeof(int),
3436 .mode = 0644,
3437 .proc_handler = proc_dointvec,
3438 },
3439 {
3440 .procname = "gc_elasticity",
3441 .data = &ip_rt_gc_elasticity,
3442 .maxlen = sizeof(int),
3443 .mode = 0644,
3444 .proc_handler = proc_dointvec,
3445 },
3446 {
3447 .procname = "mtu_expires",
3448 .data = &ip_rt_mtu_expires,
3449 .maxlen = sizeof(int),
3450 .mode = 0644,
3451 .proc_handler = proc_dointvec_jiffies,
3452 },
3453 {
3454 .procname = "min_pmtu",
3455 .data = &ip_rt_min_pmtu,
3456 .maxlen = sizeof(int),
3457 .mode = 0644,
3458 .proc_handler = proc_dointvec_minmax,
3459 .extra1 = &ip_min_valid_pmtu,
3460 },
3461 {
3462 .procname = "min_adv_mss",
3463 .data = &ip_rt_min_advmss,
3464 .maxlen = sizeof(int),
3465 .mode = 0644,
3466 .proc_handler = proc_dointvec,
3467 },
3468 { }
3469};
3470
3471static const char ipv4_route_flush_procname[] = "flush";
3472
3473static struct ctl_table ipv4_route_flush_table[] = {
3474 {
3475 .procname = ipv4_route_flush_procname,
3476 .maxlen = sizeof(int),
3477 .mode = 0200,
3478 .proc_handler = ipv4_sysctl_rtcache_flush,
3479 },
3480 { },
3481};
3482
3483static __net_init int sysctl_route_net_init(struct net *net)
3484{
3485 struct ctl_table *tbl;
3486
3487 tbl = ipv4_route_flush_table;
3488 if (!net_eq(net, &init_net)) {
3489 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3490 if (!tbl)
3491 goto err_dup;
3492
3493 /* Don't export non-whitelisted sysctls to unprivileged users */
3494 if (net->user_ns != &init_user_ns) {
3495 if (tbl[0].procname != ipv4_route_flush_procname)
3496 tbl[0].procname = NULL;
3497 }
3498 }
3499 tbl[0].extra1 = net;
3500
3501 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3502 if (!net->ipv4.route_hdr)
3503 goto err_reg;
3504 return 0;
3505
3506err_reg:
3507 if (tbl != ipv4_route_flush_table)
3508 kfree(tbl);
3509err_dup:
3510 return -ENOMEM;
3511}
3512
3513static __net_exit void sysctl_route_net_exit(struct net *net)
3514{
3515 struct ctl_table *tbl;
3516
3517 tbl = net->ipv4.route_hdr->ctl_table_arg;
3518 unregister_net_sysctl_table(net->ipv4.route_hdr);
3519 BUG_ON(tbl == ipv4_route_flush_table);
3520 kfree(tbl);
3521}
3522
3523static __net_initdata struct pernet_operations sysctl_route_ops = {
3524 .init = sysctl_route_net_init,
3525 .exit = sysctl_route_net_exit,
3526};
3527#endif
3528
3529static __net_init int rt_genid_init(struct net *net)
3530{
3531 atomic_set(&net->ipv4.rt_genid, 0);
3532 atomic_set(&net->fnhe_genid, 0);
3533 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3534 return 0;
3535}
3536
3537static __net_initdata struct pernet_operations rt_genid_ops = {
3538 .init = rt_genid_init,
3539};
3540
3541static int __net_init ipv4_inetpeer_init(struct net *net)
3542{
3543 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3544
3545 if (!bp)
3546 return -ENOMEM;
3547 inet_peer_base_init(bp);
3548 net->ipv4.peers = bp;
3549 return 0;
3550}
3551
3552static void __net_exit ipv4_inetpeer_exit(struct net *net)
3553{
3554 struct inet_peer_base *bp = net->ipv4.peers;
3555
3556 net->ipv4.peers = NULL;
3557 inetpeer_invalidate_tree(bp);
3558 kfree(bp);
3559}
3560
3561static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3562 .init = ipv4_inetpeer_init,
3563 .exit = ipv4_inetpeer_exit,
3564};
3565
3566#ifdef CONFIG_IP_ROUTE_CLASSID
3567struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3568#endif /* CONFIG_IP_ROUTE_CLASSID */
3569
3570int __init ip_rt_init(void)
3571{
3572 int cpu;
3573
3574 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents),
3575 GFP_KERNEL);
3576 if (!ip_idents)
3577 panic("IP: failed to allocate ip_idents\n");
3578
3579 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3580
3581 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3582 if (!ip_tstamps)
3583 panic("IP: failed to allocate ip_tstamps\n");
3584
3585 for_each_possible_cpu(cpu) {
3586 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3587
3588 INIT_LIST_HEAD(&ul->head);
3589 spin_lock_init(&ul->lock);
3590 }
3591#ifdef CONFIG_IP_ROUTE_CLASSID
3592 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3593 if (!ip_rt_acct)
3594 panic("IP: failed to allocate ip_rt_acct\n");
3595#endif
3596
3597 ipv4_dst_ops.kmem_cachep =
3598 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3599 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3600
3601 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3602
3603 if (dst_entries_init(&ipv4_dst_ops) < 0)
3604 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3605
3606 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3607 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3608
3609 ipv4_dst_ops.gc_thresh = ~0;
3610 ip_rt_max_size = INT_MAX;
3611
3612 devinet_init();
3613 ip_fib_init();
3614
3615 if (ip_rt_proc_init())
3616 pr_err("Unable to create route proc files\n");
3617#ifdef CONFIG_XFRM
3618 xfrm_init();
3619 xfrm4_init();
3620#endif
3621 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3622 RTNL_FLAG_DOIT_UNLOCKED);
3623
3624#ifdef CONFIG_SYSCTL
3625 register_pernet_subsys(&sysctl_route_ops);
3626#endif
3627 register_pernet_subsys(&rt_genid_ops);
3628 register_pernet_subsys(&ipv4_inetpeer_ops);
3629 return 0;
3630}
3631
3632#ifdef CONFIG_SYSCTL
3633/*
3634 * We really need to sanitize the damn ipv4 init order, then all
3635 * this nonsense will go away.
3636 */
3637void __init ip_static_sysctl_init(void)
3638{
3639 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3640}
3641#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 void ipv4_negative_advice(struct sock *sk,
136 struct dst_entry *dst);
137static void ipv4_link_failure(struct sk_buff *skb);
138static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
139 struct sk_buff *skb, u32 mtu,
140 bool confirm_neigh);
141static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
142 struct sk_buff *skb);
143static void ipv4_dst_destroy(struct dst_entry *dst);
144
145static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
146{
147 WARN_ON(1);
148 return NULL;
149}
150
151static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
152 struct sk_buff *skb,
153 const void *daddr);
154static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
155
156static struct dst_ops ipv4_dst_ops = {
157 .family = AF_INET,
158 .check = ipv4_dst_check,
159 .default_advmss = ipv4_default_advmss,
160 .mtu = ipv4_mtu,
161 .cow_metrics = ipv4_cow_metrics,
162 .destroy = ipv4_dst_destroy,
163 .negative_advice = ipv4_negative_advice,
164 .link_failure = ipv4_link_failure,
165 .update_pmtu = ip_rt_update_pmtu,
166 .redirect = ip_do_redirect,
167 .local_out = __ip_local_out,
168 .neigh_lookup = ipv4_neigh_lookup,
169 .confirm_neigh = ipv4_confirm_neigh,
170};
171
172#define ECN_OR_COST(class) TC_PRIO_##class
173
174const __u8 ip_tos2prio[16] = {
175 TC_PRIO_BESTEFFORT,
176 ECN_OR_COST(BESTEFFORT),
177 TC_PRIO_BESTEFFORT,
178 ECN_OR_COST(BESTEFFORT),
179 TC_PRIO_BULK,
180 ECN_OR_COST(BULK),
181 TC_PRIO_BULK,
182 ECN_OR_COST(BULK),
183 TC_PRIO_INTERACTIVE,
184 ECN_OR_COST(INTERACTIVE),
185 TC_PRIO_INTERACTIVE,
186 ECN_OR_COST(INTERACTIVE),
187 TC_PRIO_INTERACTIVE_BULK,
188 ECN_OR_COST(INTERACTIVE_BULK),
189 TC_PRIO_INTERACTIVE_BULK,
190 ECN_OR_COST(INTERACTIVE_BULK)
191};
192EXPORT_SYMBOL(ip_tos2prio);
193
194static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
195#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
196
197#ifdef CONFIG_PROC_FS
198static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
199{
200 if (*pos)
201 return NULL;
202 return SEQ_START_TOKEN;
203}
204
205static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
206{
207 ++*pos;
208 return NULL;
209}
210
211static void rt_cache_seq_stop(struct seq_file *seq, void *v)
212{
213}
214
215static int rt_cache_seq_show(struct seq_file *seq, void *v)
216{
217 if (v == SEQ_START_TOKEN)
218 seq_printf(seq, "%-127s\n",
219 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
220 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
221 "HHUptod\tSpecDst");
222 return 0;
223}
224
225static const struct seq_operations rt_cache_seq_ops = {
226 .start = rt_cache_seq_start,
227 .next = rt_cache_seq_next,
228 .stop = rt_cache_seq_stop,
229 .show = rt_cache_seq_show,
230};
231
232static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
233{
234 int cpu;
235
236 if (*pos == 0)
237 return SEQ_START_TOKEN;
238
239 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
240 if (!cpu_possible(cpu))
241 continue;
242 *pos = cpu+1;
243 return &per_cpu(rt_cache_stat, cpu);
244 }
245 return NULL;
246}
247
248static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
249{
250 int cpu;
251
252 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
253 if (!cpu_possible(cpu))
254 continue;
255 *pos = cpu+1;
256 return &per_cpu(rt_cache_stat, cpu);
257 }
258 (*pos)++;
259 return NULL;
260
261}
262
263static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
264{
265
266}
267
268static int rt_cpu_seq_show(struct seq_file *seq, void *v)
269{
270 struct rt_cache_stat *st = v;
271
272 if (v == SEQ_START_TOKEN) {
273 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");
274 return 0;
275 }
276
277 seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x "
278 "%08x %08x %08x %08x %08x %08x "
279 "%08x %08x %08x %08x\n",
280 dst_entries_get_slow(&ipv4_dst_ops),
281 0, /* st->in_hit */
282 st->in_slow_tot,
283 st->in_slow_mc,
284 st->in_no_route,
285 st->in_brd,
286 st->in_martian_dst,
287 st->in_martian_src,
288
289 0, /* st->out_hit */
290 st->out_slow_tot,
291 st->out_slow_mc,
292
293 0, /* st->gc_total */
294 0, /* st->gc_ignored */
295 0, /* st->gc_goal_miss */
296 0, /* st->gc_dst_overflow */
297 0, /* st->in_hlist_search */
298 0 /* st->out_hlist_search */
299 );
300 return 0;
301}
302
303static const struct seq_operations rt_cpu_seq_ops = {
304 .start = rt_cpu_seq_start,
305 .next = rt_cpu_seq_next,
306 .stop = rt_cpu_seq_stop,
307 .show = rt_cpu_seq_show,
308};
309
310#ifdef CONFIG_IP_ROUTE_CLASSID
311static int rt_acct_proc_show(struct seq_file *m, void *v)
312{
313 struct ip_rt_acct *dst, *src;
314 unsigned int i, j;
315
316 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
317 if (!dst)
318 return -ENOMEM;
319
320 for_each_possible_cpu(i) {
321 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
322 for (j = 0; j < 256; j++) {
323 dst[j].o_bytes += src[j].o_bytes;
324 dst[j].o_packets += src[j].o_packets;
325 dst[j].i_bytes += src[j].i_bytes;
326 dst[j].i_packets += src[j].i_packets;
327 }
328 }
329
330 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
331 kfree(dst);
332 return 0;
333}
334#endif
335
336static int __net_init ip_rt_do_proc_init(struct net *net)
337{
338 struct proc_dir_entry *pde;
339
340 pde = proc_create_seq("rt_cache", 0444, net->proc_net,
341 &rt_cache_seq_ops);
342 if (!pde)
343 goto err1;
344
345 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
346 &rt_cpu_seq_ops);
347 if (!pde)
348 goto err2;
349
350#ifdef CONFIG_IP_ROUTE_CLASSID
351 pde = proc_create_single("rt_acct", 0, net->proc_net,
352 rt_acct_proc_show);
353 if (!pde)
354 goto err3;
355#endif
356 return 0;
357
358#ifdef CONFIG_IP_ROUTE_CLASSID
359err3:
360 remove_proc_entry("rt_cache", net->proc_net_stat);
361#endif
362err2:
363 remove_proc_entry("rt_cache", net->proc_net);
364err1:
365 return -ENOMEM;
366}
367
368static void __net_exit ip_rt_do_proc_exit(struct net *net)
369{
370 remove_proc_entry("rt_cache", net->proc_net_stat);
371 remove_proc_entry("rt_cache", net->proc_net);
372#ifdef CONFIG_IP_ROUTE_CLASSID
373 remove_proc_entry("rt_acct", net->proc_net);
374#endif
375}
376
377static struct pernet_operations ip_rt_proc_ops __net_initdata = {
378 .init = ip_rt_do_proc_init,
379 .exit = ip_rt_do_proc_exit,
380};
381
382static int __init ip_rt_proc_init(void)
383{
384 return register_pernet_subsys(&ip_rt_proc_ops);
385}
386
387#else
388static inline int ip_rt_proc_init(void)
389{
390 return 0;
391}
392#endif /* CONFIG_PROC_FS */
393
394static inline bool rt_is_expired(const struct rtable *rth)
395{
396 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
397}
398
399void rt_cache_flush(struct net *net)
400{
401 rt_genid_bump_ipv4(net);
402}
403
404static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
405 struct sk_buff *skb,
406 const void *daddr)
407{
408 const struct rtable *rt = container_of(dst, struct rtable, dst);
409 struct net_device *dev = dst->dev;
410 struct neighbour *n;
411
412 rcu_read_lock();
413
414 if (likely(rt->rt_gw_family == AF_INET)) {
415 n = ip_neigh_gw4(dev, rt->rt_gw4);
416 } else if (rt->rt_gw_family == AF_INET6) {
417 n = ip_neigh_gw6(dev, &rt->rt_gw6);
418 } else {
419 __be32 pkey;
420
421 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
422 n = ip_neigh_gw4(dev, pkey);
423 }
424
425 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
426 n = NULL;
427
428 rcu_read_unlock();
429
430 return n;
431}
432
433static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
434{
435 const struct rtable *rt = container_of(dst, struct rtable, dst);
436 struct net_device *dev = dst->dev;
437 const __be32 *pkey = daddr;
438
439 if (rt->rt_gw_family == AF_INET) {
440 pkey = (const __be32 *)&rt->rt_gw4;
441 } else if (rt->rt_gw_family == AF_INET6) {
442 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
443 } else if (!daddr ||
444 (rt->rt_flags &
445 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
446 return;
447 }
448 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
449}
450
451/* Hash tables of size 2048..262144 depending on RAM size.
452 * Each bucket uses 8 bytes.
453 */
454static u32 ip_idents_mask __read_mostly;
455static atomic_t *ip_idents __read_mostly;
456static u32 *ip_tstamps __read_mostly;
457
458/* In order to protect privacy, we add a perturbation to identifiers
459 * if one generator is seldom used. This makes hard for an attacker
460 * to infer how many packets were sent between two points in time.
461 */
462static u32 ip_idents_reserve(u32 hash, int segs)
463{
464 u32 bucket, old, now = (u32)jiffies;
465 atomic_t *p_id;
466 u32 *p_tstamp;
467 u32 delta = 0;
468
469 bucket = hash & ip_idents_mask;
470 p_tstamp = ip_tstamps + bucket;
471 p_id = ip_idents + bucket;
472 old = READ_ONCE(*p_tstamp);
473
474 if (old != now && cmpxchg(p_tstamp, old, now) == old)
475 delta = get_random_u32_below(now - old);
476
477 /* If UBSAN reports an error there, please make sure your compiler
478 * supports -fno-strict-overflow before reporting it that was a bug
479 * in UBSAN, and it has been fixed in GCC-8.
480 */
481 return atomic_add_return(segs + delta, p_id) - segs;
482}
483
484void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
485{
486 u32 hash, id;
487
488 /* Note the following code is not safe, but this is okay. */
489 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
490 get_random_bytes(&net->ipv4.ip_id_key,
491 sizeof(net->ipv4.ip_id_key));
492
493 hash = siphash_3u32((__force u32)iph->daddr,
494 (__force u32)iph->saddr,
495 iph->protocol,
496 &net->ipv4.ip_id_key);
497 id = ip_idents_reserve(hash, segs);
498 iph->id = htons(id);
499}
500EXPORT_SYMBOL(__ip_select_ident);
501
502static void ip_rt_fix_tos(struct flowi4 *fl4)
503{
504 __u8 tos = RT_FL_TOS(fl4);
505
506 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
507 if (tos & RTO_ONLINK)
508 fl4->flowi4_scope = RT_SCOPE_LINK;
509}
510
511static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
512 const struct sock *sk, const struct iphdr *iph,
513 int oif, __u8 tos, u8 prot, u32 mark,
514 int flow_flags)
515{
516 __u8 scope = RT_SCOPE_UNIVERSE;
517
518 if (sk) {
519 oif = sk->sk_bound_dev_if;
520 mark = READ_ONCE(sk->sk_mark);
521 tos = ip_sock_rt_tos(sk);
522 scope = ip_sock_rt_scope(sk);
523 prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW :
524 sk->sk_protocol;
525 }
526
527 flowi4_init_output(fl4, oif, mark, tos & IPTOS_RT_MASK, scope,
528 prot, flow_flags, iph->daddr, iph->saddr, 0, 0,
529 sock_net_uid(net, sk));
530}
531
532static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
533 const struct sock *sk)
534{
535 const struct net *net = dev_net(skb->dev);
536 const struct iphdr *iph = ip_hdr(skb);
537 int oif = skb->dev->ifindex;
538 u8 prot = iph->protocol;
539 u32 mark = skb->mark;
540 __u8 tos = iph->tos;
541
542 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
543}
544
545static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
546{
547 const struct inet_sock *inet = inet_sk(sk);
548 const struct ip_options_rcu *inet_opt;
549 __be32 daddr = inet->inet_daddr;
550
551 rcu_read_lock();
552 inet_opt = rcu_dereference(inet->inet_opt);
553 if (inet_opt && inet_opt->opt.srr)
554 daddr = inet_opt->opt.faddr;
555 flowi4_init_output(fl4, sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark),
556 ip_sock_rt_tos(sk) & IPTOS_RT_MASK,
557 ip_sock_rt_scope(sk),
558 inet_test_bit(HDRINCL, sk) ?
559 IPPROTO_RAW : sk->sk_protocol,
560 inet_sk_flowi_flags(sk),
561 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
562 rcu_read_unlock();
563}
564
565static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
566 const struct sk_buff *skb)
567{
568 if (skb)
569 build_skb_flow_key(fl4, skb, sk);
570 else
571 build_sk_flow_key(fl4, sk);
572}
573
574static DEFINE_SPINLOCK(fnhe_lock);
575
576static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
577{
578 struct rtable *rt;
579
580 rt = rcu_dereference(fnhe->fnhe_rth_input);
581 if (rt) {
582 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
583 dst_dev_put(&rt->dst);
584 dst_release(&rt->dst);
585 }
586 rt = rcu_dereference(fnhe->fnhe_rth_output);
587 if (rt) {
588 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
589 dst_dev_put(&rt->dst);
590 dst_release(&rt->dst);
591 }
592}
593
594static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
595{
596 struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
597 struct fib_nh_exception *fnhe, *oldest = NULL;
598
599 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
600 fnhe = rcu_dereference_protected(*fnhe_p,
601 lockdep_is_held(&fnhe_lock));
602 if (!fnhe)
603 break;
604 if (!oldest ||
605 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
606 oldest = fnhe;
607 oldest_p = fnhe_p;
608 }
609 }
610 fnhe_flush_routes(oldest);
611 *oldest_p = oldest->fnhe_next;
612 kfree_rcu(oldest, rcu);
613}
614
615static u32 fnhe_hashfun(__be32 daddr)
616{
617 static siphash_aligned_key_t fnhe_hash_key;
618 u64 hval;
619
620 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
621 hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key);
622 return hash_64(hval, FNHE_HASH_SHIFT);
623}
624
625static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
626{
627 rt->rt_pmtu = fnhe->fnhe_pmtu;
628 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
629 rt->dst.expires = fnhe->fnhe_expires;
630
631 if (fnhe->fnhe_gw) {
632 rt->rt_flags |= RTCF_REDIRECTED;
633 rt->rt_uses_gateway = 1;
634 rt->rt_gw_family = AF_INET;
635 rt->rt_gw4 = fnhe->fnhe_gw;
636 }
637}
638
639static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
640 __be32 gw, u32 pmtu, bool lock,
641 unsigned long expires)
642{
643 struct fnhe_hash_bucket *hash;
644 struct fib_nh_exception *fnhe;
645 struct rtable *rt;
646 u32 genid, hval;
647 unsigned int i;
648 int depth;
649
650 genid = fnhe_genid(dev_net(nhc->nhc_dev));
651 hval = fnhe_hashfun(daddr);
652
653 spin_lock_bh(&fnhe_lock);
654
655 hash = rcu_dereference(nhc->nhc_exceptions);
656 if (!hash) {
657 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
658 if (!hash)
659 goto out_unlock;
660 rcu_assign_pointer(nhc->nhc_exceptions, hash);
661 }
662
663 hash += hval;
664
665 depth = 0;
666 for (fnhe = rcu_dereference(hash->chain); fnhe;
667 fnhe = rcu_dereference(fnhe->fnhe_next)) {
668 if (fnhe->fnhe_daddr == daddr)
669 break;
670 depth++;
671 }
672
673 if (fnhe) {
674 if (fnhe->fnhe_genid != genid)
675 fnhe->fnhe_genid = genid;
676 if (gw)
677 fnhe->fnhe_gw = gw;
678 if (pmtu) {
679 fnhe->fnhe_pmtu = pmtu;
680 fnhe->fnhe_mtu_locked = lock;
681 }
682 fnhe->fnhe_expires = max(1UL, expires);
683 /* Update all cached dsts too */
684 rt = rcu_dereference(fnhe->fnhe_rth_input);
685 if (rt)
686 fill_route_from_fnhe(rt, fnhe);
687 rt = rcu_dereference(fnhe->fnhe_rth_output);
688 if (rt)
689 fill_route_from_fnhe(rt, fnhe);
690 } else {
691 /* Randomize max depth to avoid some side channels attacks. */
692 int max_depth = FNHE_RECLAIM_DEPTH +
693 get_random_u32_below(FNHE_RECLAIM_DEPTH);
694
695 while (depth > max_depth) {
696 fnhe_remove_oldest(hash);
697 depth--;
698 }
699
700 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
701 if (!fnhe)
702 goto out_unlock;
703
704 fnhe->fnhe_next = hash->chain;
705
706 fnhe->fnhe_genid = genid;
707 fnhe->fnhe_daddr = daddr;
708 fnhe->fnhe_gw = gw;
709 fnhe->fnhe_pmtu = pmtu;
710 fnhe->fnhe_mtu_locked = lock;
711 fnhe->fnhe_expires = max(1UL, expires);
712
713 rcu_assign_pointer(hash->chain, fnhe);
714
715 /* Exception created; mark the cached routes for the nexthop
716 * stale, so anyone caching it rechecks if this exception
717 * applies to them.
718 */
719 rt = rcu_dereference(nhc->nhc_rth_input);
720 if (rt)
721 rt->dst.obsolete = DST_OBSOLETE_KILL;
722
723 for_each_possible_cpu(i) {
724 struct rtable __rcu **prt;
725
726 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
727 rt = rcu_dereference(*prt);
728 if (rt)
729 rt->dst.obsolete = DST_OBSOLETE_KILL;
730 }
731 }
732
733 fnhe->fnhe_stamp = jiffies;
734
735out_unlock:
736 spin_unlock_bh(&fnhe_lock);
737}
738
739static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
740 bool kill_route)
741{
742 __be32 new_gw = icmp_hdr(skb)->un.gateway;
743 __be32 old_gw = ip_hdr(skb)->saddr;
744 struct net_device *dev = skb->dev;
745 struct in_device *in_dev;
746 struct fib_result res;
747 struct neighbour *n;
748 struct net *net;
749
750 switch (icmp_hdr(skb)->code & 7) {
751 case ICMP_REDIR_NET:
752 case ICMP_REDIR_NETTOS:
753 case ICMP_REDIR_HOST:
754 case ICMP_REDIR_HOSTTOS:
755 break;
756
757 default:
758 return;
759 }
760
761 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
762 return;
763
764 in_dev = __in_dev_get_rcu(dev);
765 if (!in_dev)
766 return;
767
768 net = dev_net(dev);
769 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
770 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
771 ipv4_is_zeronet(new_gw))
772 goto reject_redirect;
773
774 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
775 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
776 goto reject_redirect;
777 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
778 goto reject_redirect;
779 } else {
780 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
781 goto reject_redirect;
782 }
783
784 n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw);
785 if (!n)
786 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
787 if (!IS_ERR(n)) {
788 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
789 neigh_event_send(n, NULL);
790 } else {
791 if (fib_lookup(net, fl4, &res, 0) == 0) {
792 struct fib_nh_common *nhc;
793
794 fib_select_path(net, &res, fl4, skb);
795 nhc = FIB_RES_NHC(res);
796 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
797 0, false,
798 jiffies + ip_rt_gc_timeout);
799 }
800 if (kill_route)
801 rt->dst.obsolete = DST_OBSOLETE_KILL;
802 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
803 }
804 neigh_release(n);
805 }
806 return;
807
808reject_redirect:
809#ifdef CONFIG_IP_ROUTE_VERBOSE
810 if (IN_DEV_LOG_MARTIANS(in_dev)) {
811 const struct iphdr *iph = (const struct iphdr *) skb->data;
812 __be32 daddr = iph->daddr;
813 __be32 saddr = iph->saddr;
814
815 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
816 " Advised path = %pI4 -> %pI4\n",
817 &old_gw, dev->name, &new_gw,
818 &saddr, &daddr);
819 }
820#endif
821 ;
822}
823
824static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
825{
826 struct rtable *rt;
827 struct flowi4 fl4;
828 const struct iphdr *iph = (const struct iphdr *) skb->data;
829 struct net *net = dev_net(skb->dev);
830 int oif = skb->dev->ifindex;
831 u8 prot = iph->protocol;
832 u32 mark = skb->mark;
833 __u8 tos = iph->tos;
834
835 rt = dst_rtable(dst);
836
837 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
838 __ip_do_redirect(rt, skb, &fl4, true);
839}
840
841static void ipv4_negative_advice(struct sock *sk,
842 struct dst_entry *dst)
843{
844 struct rtable *rt = dst_rtable(dst);
845
846 if ((dst->obsolete > 0) ||
847 (rt->rt_flags & RTCF_REDIRECTED) ||
848 rt->dst.expires)
849 sk_dst_reset(sk);
850}
851
852/*
853 * Algorithm:
854 * 1. The first ip_rt_redirect_number redirects are sent
855 * with exponential backoff, then we stop sending them at all,
856 * assuming that the host ignores our redirects.
857 * 2. If we did not see packets requiring redirects
858 * during ip_rt_redirect_silence, we assume that the host
859 * forgot redirected route and start to send redirects again.
860 *
861 * This algorithm is much cheaper and more intelligent than dumb load limiting
862 * in icmp.c.
863 *
864 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
865 * and "frag. need" (breaks PMTU discovery) in icmp.c.
866 */
867
868void ip_rt_send_redirect(struct sk_buff *skb)
869{
870 struct rtable *rt = skb_rtable(skb);
871 struct in_device *in_dev;
872 struct inet_peer *peer;
873 struct net *net;
874 int log_martians;
875 int vif;
876
877 rcu_read_lock();
878 in_dev = __in_dev_get_rcu(rt->dst.dev);
879 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
880 rcu_read_unlock();
881 return;
882 }
883 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
884 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
885 rcu_read_unlock();
886
887 net = dev_net(rt->dst.dev);
888 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
889 if (!peer) {
890 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
891 rt_nexthop(rt, ip_hdr(skb)->daddr));
892 return;
893 }
894
895 /* No redirected packets during ip_rt_redirect_silence;
896 * reset the algorithm.
897 */
898 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
899 peer->rate_tokens = 0;
900 peer->n_redirects = 0;
901 }
902
903 /* Too many ignored redirects; do not send anything
904 * set dst.rate_last to the last seen redirected packet.
905 */
906 if (peer->n_redirects >= ip_rt_redirect_number) {
907 peer->rate_last = jiffies;
908 goto out_put_peer;
909 }
910
911 /* Check for load limit; set rate_last to the latest sent
912 * redirect.
913 */
914 if (peer->n_redirects == 0 ||
915 time_after(jiffies,
916 (peer->rate_last +
917 (ip_rt_redirect_load << peer->n_redirects)))) {
918 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
919
920 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
921 peer->rate_last = jiffies;
922 ++peer->n_redirects;
923 if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians &&
924 peer->n_redirects == ip_rt_redirect_number)
925 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
926 &ip_hdr(skb)->saddr, inet_iif(skb),
927 &ip_hdr(skb)->daddr, &gw);
928 }
929out_put_peer:
930 inet_putpeer(peer);
931}
932
933static int ip_error(struct sk_buff *skb)
934{
935 struct rtable *rt = skb_rtable(skb);
936 struct net_device *dev = skb->dev;
937 struct in_device *in_dev;
938 struct inet_peer *peer;
939 unsigned long now;
940 struct net *net;
941 SKB_DR(reason);
942 bool send;
943 int code;
944
945 if (netif_is_l3_master(skb->dev)) {
946 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
947 if (!dev)
948 goto out;
949 }
950
951 in_dev = __in_dev_get_rcu(dev);
952
953 /* IP on this device is disabled. */
954 if (!in_dev)
955 goto out;
956
957 net = dev_net(rt->dst.dev);
958 if (!IN_DEV_FORWARD(in_dev)) {
959 switch (rt->dst.error) {
960 case EHOSTUNREACH:
961 SKB_DR_SET(reason, IP_INADDRERRORS);
962 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
963 break;
964
965 case ENETUNREACH:
966 SKB_DR_SET(reason, IP_INNOROUTES);
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 SKB_DR_SET(reason, IP_INNOROUTES);
983 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
984 break;
985 case EACCES:
986 code = ICMP_PKT_FILTERED;
987 break;
988 }
989
990 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
991 l3mdev_master_ifindex(skb->dev), 1);
992
993 send = true;
994 if (peer) {
995 now = jiffies;
996 peer->rate_tokens += now - peer->rate_last;
997 if (peer->rate_tokens > ip_rt_error_burst)
998 peer->rate_tokens = ip_rt_error_burst;
999 peer->rate_last = now;
1000 if (peer->rate_tokens >= ip_rt_error_cost)
1001 peer->rate_tokens -= ip_rt_error_cost;
1002 else
1003 send = false;
1004 inet_putpeer(peer);
1005 }
1006 if (send)
1007 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1008
1009out: kfree_skb_reason(skb, reason);
1010 return 0;
1011}
1012
1013static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1014{
1015 struct dst_entry *dst = &rt->dst;
1016 struct net *net = dev_net(dst->dev);
1017 struct fib_result res;
1018 bool lock = false;
1019 u32 old_mtu;
1020
1021 if (ip_mtu_locked(dst))
1022 return;
1023
1024 old_mtu = ipv4_mtu(dst);
1025 if (old_mtu < mtu)
1026 return;
1027
1028 if (mtu < net->ipv4.ip_rt_min_pmtu) {
1029 lock = true;
1030 mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
1031 }
1032
1033 if (rt->rt_pmtu == mtu && !lock &&
1034 time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
1035 return;
1036
1037 rcu_read_lock();
1038 if (fib_lookup(net, fl4, &res, 0) == 0) {
1039 struct fib_nh_common *nhc;
1040
1041 fib_select_path(net, &res, fl4, NULL);
1042 nhc = FIB_RES_NHC(res);
1043 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1044 jiffies + net->ipv4.ip_rt_mtu_expires);
1045 }
1046 rcu_read_unlock();
1047}
1048
1049static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1050 struct sk_buff *skb, u32 mtu,
1051 bool confirm_neigh)
1052{
1053 struct rtable *rt = dst_rtable(dst);
1054 struct flowi4 fl4;
1055
1056 ip_rt_build_flow_key(&fl4, sk, skb);
1057
1058 /* Don't make lookup fail for bridged encapsulations */
1059 if (skb && netif_is_any_bridge_port(skb->dev))
1060 fl4.flowi4_oif = 0;
1061
1062 __ip_rt_update_pmtu(rt, &fl4, mtu);
1063}
1064
1065void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1066 int oif, u8 protocol)
1067{
1068 const struct iphdr *iph = (const struct iphdr *)skb->data;
1069 struct flowi4 fl4;
1070 struct rtable *rt;
1071 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1072
1073 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, mark,
1074 0);
1075 rt = __ip_route_output_key(net, &fl4);
1076 if (!IS_ERR(rt)) {
1077 __ip_rt_update_pmtu(rt, &fl4, mtu);
1078 ip_rt_put(rt);
1079 }
1080}
1081EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1082
1083static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1084{
1085 const struct iphdr *iph = (const struct iphdr *)skb->data;
1086 struct flowi4 fl4;
1087 struct rtable *rt;
1088
1089 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1090
1091 if (!fl4.flowi4_mark)
1092 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1093
1094 rt = __ip_route_output_key(sock_net(sk), &fl4);
1095 if (!IS_ERR(rt)) {
1096 __ip_rt_update_pmtu(rt, &fl4, mtu);
1097 ip_rt_put(rt);
1098 }
1099}
1100
1101void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1102{
1103 const struct iphdr *iph = (const struct iphdr *)skb->data;
1104 struct flowi4 fl4;
1105 struct rtable *rt;
1106 struct dst_entry *odst = NULL;
1107 bool new = false;
1108 struct net *net = sock_net(sk);
1109
1110 bh_lock_sock(sk);
1111
1112 if (!ip_sk_accept_pmtu(sk))
1113 goto out;
1114
1115 odst = sk_dst_get(sk);
1116
1117 if (sock_owned_by_user(sk) || !odst) {
1118 __ipv4_sk_update_pmtu(skb, sk, mtu);
1119 goto out;
1120 }
1121
1122 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1123
1124 rt = dst_rtable(odst);
1125 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1126 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1127 if (IS_ERR(rt))
1128 goto out;
1129
1130 new = true;
1131 }
1132
1133 __ip_rt_update_pmtu(dst_rtable(xfrm_dst_path(&rt->dst)), &fl4, mtu);
1134
1135 if (!dst_check(&rt->dst, 0)) {
1136 if (new)
1137 dst_release(&rt->dst);
1138
1139 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1140 if (IS_ERR(rt))
1141 goto out;
1142
1143 new = true;
1144 }
1145
1146 if (new)
1147 sk_dst_set(sk, &rt->dst);
1148
1149out:
1150 bh_unlock_sock(sk);
1151 dst_release(odst);
1152}
1153EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1154
1155void ipv4_redirect(struct sk_buff *skb, struct net *net,
1156 int oif, u8 protocol)
1157{
1158 const struct iphdr *iph = (const struct iphdr *)skb->data;
1159 struct flowi4 fl4;
1160 struct rtable *rt;
1161
1162 __build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, 0, 0);
1163 rt = __ip_route_output_key(net, &fl4);
1164 if (!IS_ERR(rt)) {
1165 __ip_do_redirect(rt, skb, &fl4, false);
1166 ip_rt_put(rt);
1167 }
1168}
1169EXPORT_SYMBOL_GPL(ipv4_redirect);
1170
1171void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1172{
1173 const struct iphdr *iph = (const struct iphdr *)skb->data;
1174 struct flowi4 fl4;
1175 struct rtable *rt;
1176 struct net *net = sock_net(sk);
1177
1178 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1179 rt = __ip_route_output_key(net, &fl4);
1180 if (!IS_ERR(rt)) {
1181 __ip_do_redirect(rt, skb, &fl4, false);
1182 ip_rt_put(rt);
1183 }
1184}
1185EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1186
1187INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1188 u32 cookie)
1189{
1190 struct rtable *rt = dst_rtable(dst);
1191
1192 /* All IPV4 dsts are created with ->obsolete set to the value
1193 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1194 * into this function always.
1195 *
1196 * When a PMTU/redirect information update invalidates a route,
1197 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1198 * DST_OBSOLETE_DEAD.
1199 */
1200 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1201 return NULL;
1202 return dst;
1203}
1204EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1205
1206static void ipv4_send_dest_unreach(struct sk_buff *skb)
1207{
1208 struct net_device *dev;
1209 struct ip_options opt;
1210 int res;
1211
1212 /* Recompile ip options since IPCB may not be valid anymore.
1213 * Also check we have a reasonable ipv4 header.
1214 */
1215 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1216 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1217 return;
1218
1219 memset(&opt, 0, sizeof(opt));
1220 if (ip_hdr(skb)->ihl > 5) {
1221 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1222 return;
1223 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1224
1225 rcu_read_lock();
1226 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
1227 res = __ip_options_compile(dev_net(dev), &opt, skb, NULL);
1228 rcu_read_unlock();
1229
1230 if (res)
1231 return;
1232 }
1233 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1234}
1235
1236static void ipv4_link_failure(struct sk_buff *skb)
1237{
1238 struct rtable *rt;
1239
1240 ipv4_send_dest_unreach(skb);
1241
1242 rt = skb_rtable(skb);
1243 if (rt)
1244 dst_set_expires(&rt->dst, 0);
1245}
1246
1247static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1248{
1249 pr_debug("%s: %pI4 -> %pI4, %s\n",
1250 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1251 skb->dev ? skb->dev->name : "?");
1252 kfree_skb(skb);
1253 WARN_ON(1);
1254 return 0;
1255}
1256
1257/*
1258 * We do not cache source address of outgoing interface,
1259 * because it is used only by IP RR, TS and SRR options,
1260 * so that it out of fast path.
1261 *
1262 * BTW remember: "addr" is allowed to be not aligned
1263 * in IP options!
1264 */
1265
1266void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1267{
1268 __be32 src;
1269
1270 if (rt_is_output_route(rt))
1271 src = ip_hdr(skb)->saddr;
1272 else {
1273 struct fib_result res;
1274 struct iphdr *iph = ip_hdr(skb);
1275 struct flowi4 fl4 = {
1276 .daddr = iph->daddr,
1277 .saddr = iph->saddr,
1278 .flowi4_tos = RT_TOS(iph->tos),
1279 .flowi4_oif = rt->dst.dev->ifindex,
1280 .flowi4_iif = skb->dev->ifindex,
1281 .flowi4_mark = skb->mark,
1282 };
1283
1284 rcu_read_lock();
1285 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1286 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1287 else
1288 src = inet_select_addr(rt->dst.dev,
1289 rt_nexthop(rt, iph->daddr),
1290 RT_SCOPE_UNIVERSE);
1291 rcu_read_unlock();
1292 }
1293 memcpy(addr, &src, 4);
1294}
1295
1296#ifdef CONFIG_IP_ROUTE_CLASSID
1297static void set_class_tag(struct rtable *rt, u32 tag)
1298{
1299 if (!(rt->dst.tclassid & 0xFFFF))
1300 rt->dst.tclassid |= tag & 0xFFFF;
1301 if (!(rt->dst.tclassid & 0xFFFF0000))
1302 rt->dst.tclassid |= tag & 0xFFFF0000;
1303}
1304#endif
1305
1306static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1307{
1308 struct net *net = dev_net(dst->dev);
1309 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1310 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1311 net->ipv4.ip_rt_min_advmss);
1312
1313 return min(advmss, IPV4_MAX_PMTU - header_size);
1314}
1315
1316INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1317{
1318 return ip_dst_mtu_maybe_forward(dst, false);
1319}
1320EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1321
1322static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1323{
1324 struct fnhe_hash_bucket *hash;
1325 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1326 u32 hval = fnhe_hashfun(daddr);
1327
1328 spin_lock_bh(&fnhe_lock);
1329
1330 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1331 lockdep_is_held(&fnhe_lock));
1332 hash += hval;
1333
1334 fnhe_p = &hash->chain;
1335 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1336 while (fnhe) {
1337 if (fnhe->fnhe_daddr == daddr) {
1338 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1339 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1340 /* set fnhe_daddr to 0 to ensure it won't bind with
1341 * new dsts in rt_bind_exception().
1342 */
1343 fnhe->fnhe_daddr = 0;
1344 fnhe_flush_routes(fnhe);
1345 kfree_rcu(fnhe, rcu);
1346 break;
1347 }
1348 fnhe_p = &fnhe->fnhe_next;
1349 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1350 lockdep_is_held(&fnhe_lock));
1351 }
1352
1353 spin_unlock_bh(&fnhe_lock);
1354}
1355
1356static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1357 __be32 daddr)
1358{
1359 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1360 struct fib_nh_exception *fnhe;
1361 u32 hval;
1362
1363 if (!hash)
1364 return NULL;
1365
1366 hval = fnhe_hashfun(daddr);
1367
1368 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1369 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1370 if (fnhe->fnhe_daddr == daddr) {
1371 if (fnhe->fnhe_expires &&
1372 time_after(jiffies, fnhe->fnhe_expires)) {
1373 ip_del_fnhe(nhc, daddr);
1374 break;
1375 }
1376 return fnhe;
1377 }
1378 }
1379 return NULL;
1380}
1381
1382/* MTU selection:
1383 * 1. mtu on route is locked - use it
1384 * 2. mtu from nexthop exception
1385 * 3. mtu from egress device
1386 */
1387
1388u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1389{
1390 struct fib_nh_common *nhc = res->nhc;
1391 struct net_device *dev = nhc->nhc_dev;
1392 struct fib_info *fi = res->fi;
1393 u32 mtu = 0;
1394
1395 if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) ||
1396 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1397 mtu = fi->fib_mtu;
1398
1399 if (likely(!mtu)) {
1400 struct fib_nh_exception *fnhe;
1401
1402 fnhe = find_exception(nhc, daddr);
1403 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1404 mtu = fnhe->fnhe_pmtu;
1405 }
1406
1407 if (likely(!mtu))
1408 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1409
1410 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1411}
1412
1413static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1414 __be32 daddr, const bool do_cache)
1415{
1416 bool ret = false;
1417
1418 spin_lock_bh(&fnhe_lock);
1419
1420 if (daddr == fnhe->fnhe_daddr) {
1421 struct rtable __rcu **porig;
1422 struct rtable *orig;
1423 int genid = fnhe_genid(dev_net(rt->dst.dev));
1424
1425 if (rt_is_input_route(rt))
1426 porig = &fnhe->fnhe_rth_input;
1427 else
1428 porig = &fnhe->fnhe_rth_output;
1429 orig = rcu_dereference(*porig);
1430
1431 if (fnhe->fnhe_genid != genid) {
1432 fnhe->fnhe_genid = genid;
1433 fnhe->fnhe_gw = 0;
1434 fnhe->fnhe_pmtu = 0;
1435 fnhe->fnhe_expires = 0;
1436 fnhe->fnhe_mtu_locked = false;
1437 fnhe_flush_routes(fnhe);
1438 orig = NULL;
1439 }
1440 fill_route_from_fnhe(rt, fnhe);
1441 if (!rt->rt_gw4) {
1442 rt->rt_gw4 = daddr;
1443 rt->rt_gw_family = AF_INET;
1444 }
1445
1446 if (do_cache) {
1447 dst_hold(&rt->dst);
1448 rcu_assign_pointer(*porig, rt);
1449 if (orig) {
1450 dst_dev_put(&orig->dst);
1451 dst_release(&orig->dst);
1452 }
1453 ret = true;
1454 }
1455
1456 fnhe->fnhe_stamp = jiffies;
1457 }
1458 spin_unlock_bh(&fnhe_lock);
1459
1460 return ret;
1461}
1462
1463static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1464{
1465 struct rtable *orig, *prev, **p;
1466 bool ret = true;
1467
1468 if (rt_is_input_route(rt)) {
1469 p = (struct rtable **)&nhc->nhc_rth_input;
1470 } else {
1471 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1472 }
1473 orig = *p;
1474
1475 /* hold dst before doing cmpxchg() to avoid race condition
1476 * on this dst
1477 */
1478 dst_hold(&rt->dst);
1479 prev = cmpxchg(p, orig, rt);
1480 if (prev == orig) {
1481 if (orig) {
1482 rt_add_uncached_list(orig);
1483 dst_release(&orig->dst);
1484 }
1485 } else {
1486 dst_release(&rt->dst);
1487 ret = false;
1488 }
1489
1490 return ret;
1491}
1492
1493struct uncached_list {
1494 spinlock_t lock;
1495 struct list_head head;
1496 struct list_head quarantine;
1497};
1498
1499static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1500
1501void rt_add_uncached_list(struct rtable *rt)
1502{
1503 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1504
1505 rt->dst.rt_uncached_list = ul;
1506
1507 spin_lock_bh(&ul->lock);
1508 list_add_tail(&rt->dst.rt_uncached, &ul->head);
1509 spin_unlock_bh(&ul->lock);
1510}
1511
1512void rt_del_uncached_list(struct rtable *rt)
1513{
1514 if (!list_empty(&rt->dst.rt_uncached)) {
1515 struct uncached_list *ul = rt->dst.rt_uncached_list;
1516
1517 spin_lock_bh(&ul->lock);
1518 list_del_init(&rt->dst.rt_uncached);
1519 spin_unlock_bh(&ul->lock);
1520 }
1521}
1522
1523static void ipv4_dst_destroy(struct dst_entry *dst)
1524{
1525 ip_dst_metrics_put(dst);
1526 rt_del_uncached_list(dst_rtable(dst));
1527}
1528
1529void rt_flush_dev(struct net_device *dev)
1530{
1531 struct rtable *rt, *safe;
1532 int cpu;
1533
1534 for_each_possible_cpu(cpu) {
1535 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1536
1537 if (list_empty(&ul->head))
1538 continue;
1539
1540 spin_lock_bh(&ul->lock);
1541 list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) {
1542 if (rt->dst.dev != dev)
1543 continue;
1544 rt->dst.dev = blackhole_netdev;
1545 netdev_ref_replace(dev, blackhole_netdev,
1546 &rt->dst.dev_tracker, GFP_ATOMIC);
1547 list_move(&rt->dst.rt_uncached, &ul->quarantine);
1548 }
1549 spin_unlock_bh(&ul->lock);
1550 }
1551}
1552
1553static bool rt_cache_valid(const struct rtable *rt)
1554{
1555 return rt &&
1556 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1557 !rt_is_expired(rt);
1558}
1559
1560static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1561 const struct fib_result *res,
1562 struct fib_nh_exception *fnhe,
1563 struct fib_info *fi, u16 type, u32 itag,
1564 const bool do_cache)
1565{
1566 bool cached = false;
1567
1568 if (fi) {
1569 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1570
1571 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1572 rt->rt_uses_gateway = 1;
1573 rt->rt_gw_family = nhc->nhc_gw_family;
1574 /* only INET and INET6 are supported */
1575 if (likely(nhc->nhc_gw_family == AF_INET))
1576 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1577 else
1578 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1579 }
1580
1581 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1582
1583#ifdef CONFIG_IP_ROUTE_CLASSID
1584 if (nhc->nhc_family == AF_INET) {
1585 struct fib_nh *nh;
1586
1587 nh = container_of(nhc, struct fib_nh, nh_common);
1588 rt->dst.tclassid = nh->nh_tclassid;
1589 }
1590#endif
1591 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1592 if (unlikely(fnhe))
1593 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1594 else if (do_cache)
1595 cached = rt_cache_route(nhc, rt);
1596 if (unlikely(!cached)) {
1597 /* Routes we intend to cache in nexthop exception or
1598 * FIB nexthop have the DST_NOCACHE bit clear.
1599 * However, if we are unsuccessful at storing this
1600 * route into the cache we really need to set it.
1601 */
1602 if (!rt->rt_gw4) {
1603 rt->rt_gw_family = AF_INET;
1604 rt->rt_gw4 = daddr;
1605 }
1606 rt_add_uncached_list(rt);
1607 }
1608 } else
1609 rt_add_uncached_list(rt);
1610
1611#ifdef CONFIG_IP_ROUTE_CLASSID
1612#ifdef CONFIG_IP_MULTIPLE_TABLES
1613 set_class_tag(rt, res->tclassid);
1614#endif
1615 set_class_tag(rt, itag);
1616#endif
1617}
1618
1619struct rtable *rt_dst_alloc(struct net_device *dev,
1620 unsigned int flags, u16 type,
1621 bool noxfrm)
1622{
1623 struct rtable *rt;
1624
1625 rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1626 (noxfrm ? DST_NOXFRM : 0));
1627
1628 if (rt) {
1629 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1630 rt->rt_flags = flags;
1631 rt->rt_type = type;
1632 rt->rt_is_input = 0;
1633 rt->rt_iif = 0;
1634 rt->rt_pmtu = 0;
1635 rt->rt_mtu_locked = 0;
1636 rt->rt_uses_gateway = 0;
1637 rt->rt_gw_family = 0;
1638 rt->rt_gw4 = 0;
1639
1640 rt->dst.output = ip_output;
1641 if (flags & RTCF_LOCAL)
1642 rt->dst.input = ip_local_deliver;
1643 }
1644
1645 return rt;
1646}
1647EXPORT_SYMBOL(rt_dst_alloc);
1648
1649struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1650{
1651 struct rtable *new_rt;
1652
1653 new_rt = dst_alloc(&ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1654 rt->dst.flags);
1655
1656 if (new_rt) {
1657 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1658 new_rt->rt_flags = rt->rt_flags;
1659 new_rt->rt_type = rt->rt_type;
1660 new_rt->rt_is_input = rt->rt_is_input;
1661 new_rt->rt_iif = rt->rt_iif;
1662 new_rt->rt_pmtu = rt->rt_pmtu;
1663 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1664 new_rt->rt_gw_family = rt->rt_gw_family;
1665 if (rt->rt_gw_family == AF_INET)
1666 new_rt->rt_gw4 = rt->rt_gw4;
1667 else if (rt->rt_gw_family == AF_INET6)
1668 new_rt->rt_gw6 = rt->rt_gw6;
1669
1670 new_rt->dst.input = rt->dst.input;
1671 new_rt->dst.output = rt->dst.output;
1672 new_rt->dst.error = rt->dst.error;
1673 new_rt->dst.lastuse = jiffies;
1674 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1675 }
1676 return new_rt;
1677}
1678EXPORT_SYMBOL(rt_dst_clone);
1679
1680/* called in rcu_read_lock() section */
1681int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1682 u8 tos, struct net_device *dev,
1683 struct in_device *in_dev, u32 *itag)
1684{
1685 int err;
1686
1687 /* Primary sanity checks. */
1688 if (!in_dev)
1689 return -EINVAL;
1690
1691 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1692 skb->protocol != htons(ETH_P_IP))
1693 return -EINVAL;
1694
1695 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1696 return -EINVAL;
1697
1698 if (ipv4_is_zeronet(saddr)) {
1699 if (!ipv4_is_local_multicast(daddr) &&
1700 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1701 return -EINVAL;
1702 } else {
1703 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1704 in_dev, itag);
1705 if (err < 0)
1706 return err;
1707 }
1708 return 0;
1709}
1710
1711/* called in rcu_read_lock() section */
1712static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1713 u8 tos, struct net_device *dev, int our)
1714{
1715 struct in_device *in_dev = __in_dev_get_rcu(dev);
1716 unsigned int flags = RTCF_MULTICAST;
1717 struct rtable *rth;
1718 u32 itag = 0;
1719 int err;
1720
1721 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1722 if (err)
1723 return err;
1724
1725 if (our)
1726 flags |= RTCF_LOCAL;
1727
1728 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1729 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1730
1731 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1732 false);
1733 if (!rth)
1734 return -ENOBUFS;
1735
1736#ifdef CONFIG_IP_ROUTE_CLASSID
1737 rth->dst.tclassid = itag;
1738#endif
1739 rth->dst.output = ip_rt_bug;
1740 rth->rt_is_input= 1;
1741
1742#ifdef CONFIG_IP_MROUTE
1743 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1744 rth->dst.input = ip_mr_input;
1745#endif
1746 RT_CACHE_STAT_INC(in_slow_mc);
1747
1748 skb_dst_drop(skb);
1749 skb_dst_set(skb, &rth->dst);
1750 return 0;
1751}
1752
1753
1754static void ip_handle_martian_source(struct net_device *dev,
1755 struct in_device *in_dev,
1756 struct sk_buff *skb,
1757 __be32 daddr,
1758 __be32 saddr)
1759{
1760 RT_CACHE_STAT_INC(in_martian_src);
1761#ifdef CONFIG_IP_ROUTE_VERBOSE
1762 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1763 /*
1764 * RFC1812 recommendation, if source is martian,
1765 * the only hint is MAC header.
1766 */
1767 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1768 &daddr, &saddr, dev->name);
1769 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1770 print_hex_dump(KERN_WARNING, "ll header: ",
1771 DUMP_PREFIX_OFFSET, 16, 1,
1772 skb_mac_header(skb),
1773 dev->hard_header_len, false);
1774 }
1775 }
1776#endif
1777}
1778
1779/* called in rcu_read_lock() section */
1780static int __mkroute_input(struct sk_buff *skb,
1781 const struct fib_result *res,
1782 struct in_device *in_dev,
1783 __be32 daddr, __be32 saddr, u32 tos)
1784{
1785 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1786 struct net_device *dev = nhc->nhc_dev;
1787 struct fib_nh_exception *fnhe;
1788 struct rtable *rth;
1789 int err;
1790 struct in_device *out_dev;
1791 bool do_cache;
1792 u32 itag = 0;
1793
1794 /* get a working reference to the output device */
1795 out_dev = __in_dev_get_rcu(dev);
1796 if (!out_dev) {
1797 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1798 return -EINVAL;
1799 }
1800
1801 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1802 in_dev->dev, in_dev, &itag);
1803 if (err < 0) {
1804 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1805 saddr);
1806
1807 goto cleanup;
1808 }
1809
1810 do_cache = res->fi && !itag;
1811 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1812 skb->protocol == htons(ETH_P_IP)) {
1813 __be32 gw;
1814
1815 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1816 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1817 inet_addr_onlink(out_dev, saddr, gw))
1818 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1819 }
1820
1821 if (skb->protocol != htons(ETH_P_IP)) {
1822 /* Not IP (i.e. ARP). Do not create route, if it is
1823 * invalid for proxy arp. DNAT routes are always valid.
1824 *
1825 * Proxy arp feature have been extended to allow, ARP
1826 * replies back to the same interface, to support
1827 * Private VLAN switch technologies. See arp.c.
1828 */
1829 if (out_dev == in_dev &&
1830 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1831 err = -EINVAL;
1832 goto cleanup;
1833 }
1834 }
1835
1836 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1837 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1838
1839 fnhe = find_exception(nhc, daddr);
1840 if (do_cache) {
1841 if (fnhe)
1842 rth = rcu_dereference(fnhe->fnhe_rth_input);
1843 else
1844 rth = rcu_dereference(nhc->nhc_rth_input);
1845 if (rt_cache_valid(rth)) {
1846 skb_dst_set_noref(skb, &rth->dst);
1847 goto out;
1848 }
1849 }
1850
1851 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1852 IN_DEV_ORCONF(out_dev, NOXFRM));
1853 if (!rth) {
1854 err = -ENOBUFS;
1855 goto cleanup;
1856 }
1857
1858 rth->rt_is_input = 1;
1859 RT_CACHE_STAT_INC(in_slow_tot);
1860
1861 rth->dst.input = ip_forward;
1862
1863 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1864 do_cache);
1865 lwtunnel_set_redirect(&rth->dst);
1866 skb_dst_set(skb, &rth->dst);
1867out:
1868 err = 0;
1869 cleanup:
1870 return err;
1871}
1872
1873#ifdef CONFIG_IP_ROUTE_MULTIPATH
1874/* To make ICMP packets follow the right flow, the multipath hash is
1875 * calculated from the inner IP addresses.
1876 */
1877static void ip_multipath_l3_keys(const struct sk_buff *skb,
1878 struct flow_keys *hash_keys)
1879{
1880 const struct iphdr *outer_iph = ip_hdr(skb);
1881 const struct iphdr *key_iph = outer_iph;
1882 const struct iphdr *inner_iph;
1883 const struct icmphdr *icmph;
1884 struct iphdr _inner_iph;
1885 struct icmphdr _icmph;
1886
1887 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1888 goto out;
1889
1890 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1891 goto out;
1892
1893 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1894 &_icmph);
1895 if (!icmph)
1896 goto out;
1897
1898 if (!icmp_is_err(icmph->type))
1899 goto out;
1900
1901 inner_iph = skb_header_pointer(skb,
1902 outer_iph->ihl * 4 + sizeof(_icmph),
1903 sizeof(_inner_iph), &_inner_iph);
1904 if (!inner_iph)
1905 goto out;
1906
1907 key_iph = inner_iph;
1908out:
1909 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1910 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1911}
1912
1913static u32 fib_multipath_custom_hash_outer(const struct net *net,
1914 const struct sk_buff *skb,
1915 bool *p_has_inner)
1916{
1917 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1918 struct flow_keys keys, hash_keys;
1919
1920 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1921 return 0;
1922
1923 memset(&hash_keys, 0, sizeof(hash_keys));
1924 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1925
1926 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1927 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1928 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1929 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1930 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1931 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1932 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1933 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1934 hash_keys.ports.src = keys.ports.src;
1935 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1936 hash_keys.ports.dst = keys.ports.dst;
1937
1938 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1939 return flow_hash_from_keys(&hash_keys);
1940}
1941
1942static u32 fib_multipath_custom_hash_inner(const struct net *net,
1943 const struct sk_buff *skb,
1944 bool has_inner)
1945{
1946 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1947 struct flow_keys keys, hash_keys;
1948
1949 /* We assume the packet carries an encapsulation, but if none was
1950 * encountered during dissection of the outer flow, then there is no
1951 * point in calling the flow dissector again.
1952 */
1953 if (!has_inner)
1954 return 0;
1955
1956 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1957 return 0;
1958
1959 memset(&hash_keys, 0, sizeof(hash_keys));
1960 skb_flow_dissect_flow_keys(skb, &keys, 0);
1961
1962 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1963 return 0;
1964
1965 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1966 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1967 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1968 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1969 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1970 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1971 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1972 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1973 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1974 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1975 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1976 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1977 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1978 hash_keys.tags.flow_label = keys.tags.flow_label;
1979 }
1980
1981 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
1982 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1983 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
1984 hash_keys.ports.src = keys.ports.src;
1985 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
1986 hash_keys.ports.dst = keys.ports.dst;
1987
1988 return flow_hash_from_keys(&hash_keys);
1989}
1990
1991static u32 fib_multipath_custom_hash_skb(const struct net *net,
1992 const struct sk_buff *skb)
1993{
1994 u32 mhash, mhash_inner;
1995 bool has_inner = true;
1996
1997 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
1998 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
1999
2000 return jhash_2words(mhash, mhash_inner, 0);
2001}
2002
2003static u32 fib_multipath_custom_hash_fl4(const struct net *net,
2004 const struct flowi4 *fl4)
2005{
2006 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
2007 struct flow_keys hash_keys;
2008
2009 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
2010 return 0;
2011
2012 memset(&hash_keys, 0, sizeof(hash_keys));
2013 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2014 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2015 hash_keys.addrs.v4addrs.src = fl4->saddr;
2016 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2017 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2018 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2019 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2020 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2021 hash_keys.ports.src = fl4->fl4_sport;
2022 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2023 hash_keys.ports.dst = fl4->fl4_dport;
2024
2025 return flow_hash_from_keys(&hash_keys);
2026}
2027
2028/* if skb is set it will be used and fl4 can be NULL */
2029int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2030 const struct sk_buff *skb, struct flow_keys *flkeys)
2031{
2032 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2033 struct flow_keys hash_keys;
2034 u32 mhash = 0;
2035
2036 switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
2037 case 0:
2038 memset(&hash_keys, 0, sizeof(hash_keys));
2039 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2040 if (skb) {
2041 ip_multipath_l3_keys(skb, &hash_keys);
2042 } else {
2043 hash_keys.addrs.v4addrs.src = fl4->saddr;
2044 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2045 }
2046 mhash = flow_hash_from_keys(&hash_keys);
2047 break;
2048 case 1:
2049 /* skb is currently provided only when forwarding */
2050 if (skb) {
2051 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2052 struct flow_keys keys;
2053
2054 /* short-circuit if we already have L4 hash present */
2055 if (skb->l4_hash)
2056 return skb_get_hash_raw(skb) >> 1;
2057
2058 memset(&hash_keys, 0, sizeof(hash_keys));
2059
2060 if (!flkeys) {
2061 skb_flow_dissect_flow_keys(skb, &keys, flag);
2062 flkeys = &keys;
2063 }
2064
2065 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2066 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2067 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2068 hash_keys.ports.src = flkeys->ports.src;
2069 hash_keys.ports.dst = flkeys->ports.dst;
2070 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2071 } else {
2072 memset(&hash_keys, 0, sizeof(hash_keys));
2073 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2074 hash_keys.addrs.v4addrs.src = fl4->saddr;
2075 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2076 hash_keys.ports.src = fl4->fl4_sport;
2077 hash_keys.ports.dst = fl4->fl4_dport;
2078 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2079 }
2080 mhash = flow_hash_from_keys(&hash_keys);
2081 break;
2082 case 2:
2083 memset(&hash_keys, 0, sizeof(hash_keys));
2084 /* skb is currently provided only when forwarding */
2085 if (skb) {
2086 struct flow_keys keys;
2087
2088 skb_flow_dissect_flow_keys(skb, &keys, 0);
2089 /* Inner can be v4 or v6 */
2090 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2091 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2092 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2093 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2094 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2095 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2096 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2097 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2098 hash_keys.tags.flow_label = keys.tags.flow_label;
2099 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2100 } else {
2101 /* Same as case 0 */
2102 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2103 ip_multipath_l3_keys(skb, &hash_keys);
2104 }
2105 } else {
2106 /* Same as case 0 */
2107 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2108 hash_keys.addrs.v4addrs.src = fl4->saddr;
2109 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2110 }
2111 mhash = flow_hash_from_keys(&hash_keys);
2112 break;
2113 case 3:
2114 if (skb)
2115 mhash = fib_multipath_custom_hash_skb(net, skb);
2116 else
2117 mhash = fib_multipath_custom_hash_fl4(net, fl4);
2118 break;
2119 }
2120
2121 if (multipath_hash)
2122 mhash = jhash_2words(mhash, multipath_hash, 0);
2123
2124 return mhash >> 1;
2125}
2126#endif /* CONFIG_IP_ROUTE_MULTIPATH */
2127
2128static int ip_mkroute_input(struct sk_buff *skb,
2129 struct fib_result *res,
2130 struct in_device *in_dev,
2131 __be32 daddr, __be32 saddr, u32 tos,
2132 struct flow_keys *hkeys)
2133{
2134#ifdef CONFIG_IP_ROUTE_MULTIPATH
2135 if (res->fi && fib_info_num_path(res->fi) > 1) {
2136 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2137
2138 fib_select_multipath(res, h);
2139 IPCB(skb)->flags |= IPSKB_MULTIPATH;
2140 }
2141#endif
2142
2143 /* create a routing cache entry */
2144 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2145}
2146
2147/* Implements all the saddr-related checks as ip_route_input_slow(),
2148 * assuming daddr is valid and the destination is not a local broadcast one.
2149 * Uses the provided hint instead of performing a route lookup.
2150 */
2151int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2152 u8 tos, struct net_device *dev,
2153 const struct sk_buff *hint)
2154{
2155 struct in_device *in_dev = __in_dev_get_rcu(dev);
2156 struct rtable *rt = skb_rtable(hint);
2157 struct net *net = dev_net(dev);
2158 int err = -EINVAL;
2159 u32 tag = 0;
2160
2161 if (!in_dev)
2162 return -EINVAL;
2163
2164 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2165 goto martian_source;
2166
2167 if (ipv4_is_zeronet(saddr))
2168 goto martian_source;
2169
2170 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2171 goto martian_source;
2172
2173 if (rt->rt_type != RTN_LOCAL)
2174 goto skip_validate_source;
2175
2176 tos &= IPTOS_RT_MASK;
2177 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2178 if (err < 0)
2179 goto martian_source;
2180
2181skip_validate_source:
2182 skb_dst_copy(skb, hint);
2183 return 0;
2184
2185martian_source:
2186 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2187 return err;
2188}
2189
2190/* get device for dst_alloc with local routes */
2191static struct net_device *ip_rt_get_dev(struct net *net,
2192 const struct fib_result *res)
2193{
2194 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2195 struct net_device *dev = NULL;
2196
2197 if (nhc)
2198 dev = l3mdev_master_dev_rcu(nhc->nhc_dev);
2199
2200 return dev ? : net->loopback_dev;
2201}
2202
2203/*
2204 * NOTE. We drop all the packets that has local source
2205 * addresses, because every properly looped back packet
2206 * must have correct destination already attached by output routine.
2207 * Changes in the enforced policies must be applied also to
2208 * ip_route_use_hint().
2209 *
2210 * Such approach solves two big problems:
2211 * 1. Not simplex devices are handled properly.
2212 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2213 * called with rcu_read_lock()
2214 */
2215
2216static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2217 u8 tos, struct net_device *dev,
2218 struct fib_result *res)
2219{
2220 struct in_device *in_dev = __in_dev_get_rcu(dev);
2221 struct flow_keys *flkeys = NULL, _flkeys;
2222 struct net *net = dev_net(dev);
2223 struct ip_tunnel_info *tun_info;
2224 int err = -EINVAL;
2225 unsigned int flags = 0;
2226 u32 itag = 0;
2227 struct rtable *rth;
2228 struct flowi4 fl4;
2229 bool do_cache = true;
2230
2231 /* IP on this device is disabled. */
2232
2233 if (!in_dev)
2234 goto out;
2235
2236 /* Check for the most weird martians, which can be not detected
2237 * by fib_lookup.
2238 */
2239
2240 tun_info = skb_tunnel_info(skb);
2241 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2242 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2243 else
2244 fl4.flowi4_tun_key.tun_id = 0;
2245 skb_dst_drop(skb);
2246
2247 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2248 goto martian_source;
2249
2250 res->fi = NULL;
2251 res->table = NULL;
2252 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2253 goto brd_input;
2254
2255 /* Accept zero addresses only to limited broadcast;
2256 * I even do not know to fix it or not. Waiting for complains :-)
2257 */
2258 if (ipv4_is_zeronet(saddr))
2259 goto martian_source;
2260
2261 if (ipv4_is_zeronet(daddr))
2262 goto martian_destination;
2263
2264 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2265 * and call it once if daddr or/and saddr are loopback addresses
2266 */
2267 if (ipv4_is_loopback(daddr)) {
2268 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2269 goto martian_destination;
2270 } else if (ipv4_is_loopback(saddr)) {
2271 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2272 goto martian_source;
2273 }
2274
2275 /*
2276 * Now we are ready to route packet.
2277 */
2278 fl4.flowi4_l3mdev = 0;
2279 fl4.flowi4_oif = 0;
2280 fl4.flowi4_iif = dev->ifindex;
2281 fl4.flowi4_mark = skb->mark;
2282 fl4.flowi4_tos = tos;
2283 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2284 fl4.flowi4_flags = 0;
2285 fl4.daddr = daddr;
2286 fl4.saddr = saddr;
2287 fl4.flowi4_uid = sock_net_uid(net, NULL);
2288 fl4.flowi4_multipath_hash = 0;
2289
2290 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2291 flkeys = &_flkeys;
2292 } else {
2293 fl4.flowi4_proto = 0;
2294 fl4.fl4_sport = 0;
2295 fl4.fl4_dport = 0;
2296 }
2297
2298 err = fib_lookup(net, &fl4, res, 0);
2299 if (err != 0) {
2300 if (!IN_DEV_FORWARD(in_dev))
2301 err = -EHOSTUNREACH;
2302 goto no_route;
2303 }
2304
2305 if (res->type == RTN_BROADCAST) {
2306 if (IN_DEV_BFORWARD(in_dev))
2307 goto make_route;
2308 /* not do cache if bc_forwarding is enabled */
2309 if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING))
2310 do_cache = false;
2311 goto brd_input;
2312 }
2313
2314 if (res->type == RTN_LOCAL) {
2315 err = fib_validate_source(skb, saddr, daddr, tos,
2316 0, dev, in_dev, &itag);
2317 if (err < 0)
2318 goto martian_source;
2319 goto local_input;
2320 }
2321
2322 if (!IN_DEV_FORWARD(in_dev)) {
2323 err = -EHOSTUNREACH;
2324 goto no_route;
2325 }
2326 if (res->type != RTN_UNICAST)
2327 goto martian_destination;
2328
2329make_route:
2330 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2331out: return err;
2332
2333brd_input:
2334 if (skb->protocol != htons(ETH_P_IP))
2335 goto e_inval;
2336
2337 if (!ipv4_is_zeronet(saddr)) {
2338 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2339 in_dev, &itag);
2340 if (err < 0)
2341 goto martian_source;
2342 }
2343 flags |= RTCF_BROADCAST;
2344 res->type = RTN_BROADCAST;
2345 RT_CACHE_STAT_INC(in_brd);
2346
2347local_input:
2348 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
2349 IPCB(skb)->flags |= IPSKB_NOPOLICY;
2350
2351 do_cache &= res->fi && !itag;
2352 if (do_cache) {
2353 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2354
2355 rth = rcu_dereference(nhc->nhc_rth_input);
2356 if (rt_cache_valid(rth)) {
2357 skb_dst_set_noref(skb, &rth->dst);
2358 err = 0;
2359 goto out;
2360 }
2361 }
2362
2363 rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2364 flags | RTCF_LOCAL, res->type, false);
2365 if (!rth)
2366 goto e_nobufs;
2367
2368 rth->dst.output= ip_rt_bug;
2369#ifdef CONFIG_IP_ROUTE_CLASSID
2370 rth->dst.tclassid = itag;
2371#endif
2372 rth->rt_is_input = 1;
2373
2374 RT_CACHE_STAT_INC(in_slow_tot);
2375 if (res->type == RTN_UNREACHABLE) {
2376 rth->dst.input= ip_error;
2377 rth->dst.error= -err;
2378 rth->rt_flags &= ~RTCF_LOCAL;
2379 }
2380
2381 if (do_cache) {
2382 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2383
2384 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2385 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2386 WARN_ON(rth->dst.input == lwtunnel_input);
2387 rth->dst.lwtstate->orig_input = rth->dst.input;
2388 rth->dst.input = lwtunnel_input;
2389 }
2390
2391 if (unlikely(!rt_cache_route(nhc, rth)))
2392 rt_add_uncached_list(rth);
2393 }
2394 skb_dst_set(skb, &rth->dst);
2395 err = 0;
2396 goto out;
2397
2398no_route:
2399 RT_CACHE_STAT_INC(in_no_route);
2400 res->type = RTN_UNREACHABLE;
2401 res->fi = NULL;
2402 res->table = NULL;
2403 goto local_input;
2404
2405 /*
2406 * Do not cache martian addresses: they should be logged (RFC1812)
2407 */
2408martian_destination:
2409 RT_CACHE_STAT_INC(in_martian_dst);
2410#ifdef CONFIG_IP_ROUTE_VERBOSE
2411 if (IN_DEV_LOG_MARTIANS(in_dev))
2412 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2413 &daddr, &saddr, dev->name);
2414#endif
2415
2416e_inval:
2417 err = -EINVAL;
2418 goto out;
2419
2420e_nobufs:
2421 err = -ENOBUFS;
2422 goto out;
2423
2424martian_source:
2425 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2426 goto out;
2427}
2428
2429/* called with rcu_read_lock held */
2430static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2431 u8 tos, struct net_device *dev, struct fib_result *res)
2432{
2433 /* Multicast recognition logic is moved from route cache to here.
2434 * The problem was that too many Ethernet cards have broken/missing
2435 * hardware multicast filters :-( As result the host on multicasting
2436 * network acquires a lot of useless route cache entries, sort of
2437 * SDR messages from all the world. Now we try to get rid of them.
2438 * Really, provided software IP multicast filter is organized
2439 * reasonably (at least, hashed), it does not result in a slowdown
2440 * comparing with route cache reject entries.
2441 * Note, that multicast routers are not affected, because
2442 * route cache entry is created eventually.
2443 */
2444 if (ipv4_is_multicast(daddr)) {
2445 struct in_device *in_dev = __in_dev_get_rcu(dev);
2446 int our = 0;
2447 int err = -EINVAL;
2448
2449 if (!in_dev)
2450 return err;
2451 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2452 ip_hdr(skb)->protocol);
2453
2454 /* check l3 master if no match yet */
2455 if (!our && netif_is_l3_slave(dev)) {
2456 struct in_device *l3_in_dev;
2457
2458 l3_in_dev = __in_dev_get_rcu(skb->dev);
2459 if (l3_in_dev)
2460 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2461 ip_hdr(skb)->protocol);
2462 }
2463
2464 if (our
2465#ifdef CONFIG_IP_MROUTE
2466 ||
2467 (!ipv4_is_local_multicast(daddr) &&
2468 IN_DEV_MFORWARD(in_dev))
2469#endif
2470 ) {
2471 err = ip_route_input_mc(skb, daddr, saddr,
2472 tos, dev, our);
2473 }
2474 return err;
2475 }
2476
2477 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2478}
2479
2480int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2481 u8 tos, struct net_device *dev)
2482{
2483 struct fib_result res;
2484 int err;
2485
2486 tos &= IPTOS_RT_MASK;
2487 rcu_read_lock();
2488 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2489 rcu_read_unlock();
2490
2491 return err;
2492}
2493EXPORT_SYMBOL(ip_route_input_noref);
2494
2495/* called with rcu_read_lock() */
2496static struct rtable *__mkroute_output(const struct fib_result *res,
2497 const struct flowi4 *fl4, int orig_oif,
2498 struct net_device *dev_out,
2499 unsigned int flags)
2500{
2501 struct fib_info *fi = res->fi;
2502 struct fib_nh_exception *fnhe;
2503 struct in_device *in_dev;
2504 u16 type = res->type;
2505 struct rtable *rth;
2506 bool do_cache;
2507
2508 in_dev = __in_dev_get_rcu(dev_out);
2509 if (!in_dev)
2510 return ERR_PTR(-EINVAL);
2511
2512 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2513 if (ipv4_is_loopback(fl4->saddr) &&
2514 !(dev_out->flags & IFF_LOOPBACK) &&
2515 !netif_is_l3_master(dev_out))
2516 return ERR_PTR(-EINVAL);
2517
2518 if (ipv4_is_lbcast(fl4->daddr))
2519 type = RTN_BROADCAST;
2520 else if (ipv4_is_multicast(fl4->daddr))
2521 type = RTN_MULTICAST;
2522 else if (ipv4_is_zeronet(fl4->daddr))
2523 return ERR_PTR(-EINVAL);
2524
2525 if (dev_out->flags & IFF_LOOPBACK)
2526 flags |= RTCF_LOCAL;
2527
2528 do_cache = true;
2529 if (type == RTN_BROADCAST) {
2530 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2531 fi = NULL;
2532 } else if (type == RTN_MULTICAST) {
2533 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2534 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2535 fl4->flowi4_proto))
2536 flags &= ~RTCF_LOCAL;
2537 else
2538 do_cache = false;
2539 /* If multicast route do not exist use
2540 * default one, but do not gateway in this case.
2541 * Yes, it is hack.
2542 */
2543 if (fi && res->prefixlen < 4)
2544 fi = NULL;
2545 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2546 (orig_oif != dev_out->ifindex)) {
2547 /* For local routes that require a particular output interface
2548 * we do not want to cache the result. Caching the result
2549 * causes incorrect behaviour when there are multiple source
2550 * addresses on the interface, the end result being that if the
2551 * intended recipient is waiting on that interface for the
2552 * packet he won't receive it because it will be delivered on
2553 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2554 * be set to the loopback interface as well.
2555 */
2556 do_cache = false;
2557 }
2558
2559 fnhe = NULL;
2560 do_cache &= fi != NULL;
2561 if (fi) {
2562 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2563 struct rtable __rcu **prth;
2564
2565 fnhe = find_exception(nhc, fl4->daddr);
2566 if (!do_cache)
2567 goto add;
2568 if (fnhe) {
2569 prth = &fnhe->fnhe_rth_output;
2570 } else {
2571 if (unlikely(fl4->flowi4_flags &
2572 FLOWI_FLAG_KNOWN_NH &&
2573 !(nhc->nhc_gw_family &&
2574 nhc->nhc_scope == RT_SCOPE_LINK))) {
2575 do_cache = false;
2576 goto add;
2577 }
2578 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2579 }
2580 rth = rcu_dereference(*prth);
2581 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2582 return rth;
2583 }
2584
2585add:
2586 rth = rt_dst_alloc(dev_out, flags, type,
2587 IN_DEV_ORCONF(in_dev, NOXFRM));
2588 if (!rth)
2589 return ERR_PTR(-ENOBUFS);
2590
2591 rth->rt_iif = orig_oif;
2592
2593 RT_CACHE_STAT_INC(out_slow_tot);
2594
2595 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2596 if (flags & RTCF_LOCAL &&
2597 !(dev_out->flags & IFF_LOOPBACK)) {
2598 rth->dst.output = ip_mc_output;
2599 RT_CACHE_STAT_INC(out_slow_mc);
2600 }
2601#ifdef CONFIG_IP_MROUTE
2602 if (type == RTN_MULTICAST) {
2603 if (IN_DEV_MFORWARD(in_dev) &&
2604 !ipv4_is_local_multicast(fl4->daddr)) {
2605 rth->dst.input = ip_mr_input;
2606 rth->dst.output = ip_mc_output;
2607 }
2608 }
2609#endif
2610 }
2611
2612 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2613 lwtunnel_set_redirect(&rth->dst);
2614
2615 return rth;
2616}
2617
2618/*
2619 * Major route resolver routine.
2620 */
2621
2622struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2623 const struct sk_buff *skb)
2624{
2625 struct fib_result res = {
2626 .type = RTN_UNSPEC,
2627 .fi = NULL,
2628 .table = NULL,
2629 .tclassid = 0,
2630 };
2631 struct rtable *rth;
2632
2633 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2634 ip_rt_fix_tos(fl4);
2635
2636 rcu_read_lock();
2637 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2638 rcu_read_unlock();
2639
2640 return rth;
2641}
2642EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2643
2644struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2645 struct fib_result *res,
2646 const struct sk_buff *skb)
2647{
2648 struct net_device *dev_out = NULL;
2649 int orig_oif = fl4->flowi4_oif;
2650 unsigned int flags = 0;
2651 struct rtable *rth;
2652 int err;
2653
2654 if (fl4->saddr) {
2655 if (ipv4_is_multicast(fl4->saddr) ||
2656 ipv4_is_lbcast(fl4->saddr) ||
2657 ipv4_is_zeronet(fl4->saddr)) {
2658 rth = ERR_PTR(-EINVAL);
2659 goto out;
2660 }
2661
2662 rth = ERR_PTR(-ENETUNREACH);
2663
2664 /* I removed check for oif == dev_out->oif here.
2665 * It was wrong for two reasons:
2666 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2667 * is assigned to multiple interfaces.
2668 * 2. Moreover, we are allowed to send packets with saddr
2669 * of another iface. --ANK
2670 */
2671
2672 if (fl4->flowi4_oif == 0 &&
2673 (ipv4_is_multicast(fl4->daddr) ||
2674 ipv4_is_lbcast(fl4->daddr))) {
2675 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2676 dev_out = __ip_dev_find(net, fl4->saddr, false);
2677 if (!dev_out)
2678 goto out;
2679
2680 /* Special hack: user can direct multicasts
2681 * and limited broadcast via necessary interface
2682 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2683 * This hack is not just for fun, it allows
2684 * vic,vat and friends to work.
2685 * They bind socket to loopback, set ttl to zero
2686 * and expect that it will work.
2687 * From the viewpoint of routing cache they are broken,
2688 * because we are not allowed to build multicast path
2689 * with loopback source addr (look, routing cache
2690 * cannot know, that ttl is zero, so that packet
2691 * will not leave this host and route is valid).
2692 * Luckily, this hack is good workaround.
2693 */
2694
2695 fl4->flowi4_oif = dev_out->ifindex;
2696 goto make_route;
2697 }
2698
2699 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2700 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2701 if (!__ip_dev_find(net, fl4->saddr, false))
2702 goto out;
2703 }
2704 }
2705
2706
2707 if (fl4->flowi4_oif) {
2708 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2709 rth = ERR_PTR(-ENODEV);
2710 if (!dev_out)
2711 goto out;
2712
2713 /* RACE: Check return value of inet_select_addr instead. */
2714 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2715 rth = ERR_PTR(-ENETUNREACH);
2716 goto out;
2717 }
2718 if (ipv4_is_local_multicast(fl4->daddr) ||
2719 ipv4_is_lbcast(fl4->daddr) ||
2720 fl4->flowi4_proto == IPPROTO_IGMP) {
2721 if (!fl4->saddr)
2722 fl4->saddr = inet_select_addr(dev_out, 0,
2723 RT_SCOPE_LINK);
2724 goto make_route;
2725 }
2726 if (!fl4->saddr) {
2727 if (ipv4_is_multicast(fl4->daddr))
2728 fl4->saddr = inet_select_addr(dev_out, 0,
2729 fl4->flowi4_scope);
2730 else if (!fl4->daddr)
2731 fl4->saddr = inet_select_addr(dev_out, 0,
2732 RT_SCOPE_HOST);
2733 }
2734 }
2735
2736 if (!fl4->daddr) {
2737 fl4->daddr = fl4->saddr;
2738 if (!fl4->daddr)
2739 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2740 dev_out = net->loopback_dev;
2741 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2742 res->type = RTN_LOCAL;
2743 flags |= RTCF_LOCAL;
2744 goto make_route;
2745 }
2746
2747 err = fib_lookup(net, fl4, res, 0);
2748 if (err) {
2749 res->fi = NULL;
2750 res->table = NULL;
2751 if (fl4->flowi4_oif &&
2752 (ipv4_is_multicast(fl4->daddr) || !fl4->flowi4_l3mdev)) {
2753 /* Apparently, routing tables are wrong. Assume,
2754 * that the destination is on link.
2755 *
2756 * WHY? DW.
2757 * Because we are allowed to send to iface
2758 * even if it has NO routes and NO assigned
2759 * addresses. When oif is specified, routing
2760 * tables are looked up with only one purpose:
2761 * to catch if destination is gatewayed, rather than
2762 * direct. Moreover, if MSG_DONTROUTE is set,
2763 * we send packet, ignoring both routing tables
2764 * and ifaddr state. --ANK
2765 *
2766 *
2767 * We could make it even if oif is unknown,
2768 * likely IPv6, but we do not.
2769 */
2770
2771 if (fl4->saddr == 0)
2772 fl4->saddr = inet_select_addr(dev_out, 0,
2773 RT_SCOPE_LINK);
2774 res->type = RTN_UNICAST;
2775 goto make_route;
2776 }
2777 rth = ERR_PTR(err);
2778 goto out;
2779 }
2780
2781 if (res->type == RTN_LOCAL) {
2782 if (!fl4->saddr) {
2783 if (res->fi->fib_prefsrc)
2784 fl4->saddr = res->fi->fib_prefsrc;
2785 else
2786 fl4->saddr = fl4->daddr;
2787 }
2788
2789 /* L3 master device is the loopback for that domain */
2790 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2791 net->loopback_dev;
2792
2793 /* make sure orig_oif points to fib result device even
2794 * though packet rx/tx happens over loopback or l3mdev
2795 */
2796 orig_oif = FIB_RES_OIF(*res);
2797
2798 fl4->flowi4_oif = dev_out->ifindex;
2799 flags |= RTCF_LOCAL;
2800 goto make_route;
2801 }
2802
2803 fib_select_path(net, res, fl4, skb);
2804
2805 dev_out = FIB_RES_DEV(*res);
2806
2807make_route:
2808 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2809
2810out:
2811 return rth;
2812}
2813
2814static struct dst_ops ipv4_dst_blackhole_ops = {
2815 .family = AF_INET,
2816 .default_advmss = ipv4_default_advmss,
2817 .neigh_lookup = ipv4_neigh_lookup,
2818 .check = dst_blackhole_check,
2819 .cow_metrics = dst_blackhole_cow_metrics,
2820 .update_pmtu = dst_blackhole_update_pmtu,
2821 .redirect = dst_blackhole_redirect,
2822 .mtu = dst_blackhole_mtu,
2823};
2824
2825struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2826{
2827 struct rtable *ort = dst_rtable(dst_orig);
2828 struct rtable *rt;
2829
2830 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, 0);
2831 if (rt) {
2832 struct dst_entry *new = &rt->dst;
2833
2834 new->__use = 1;
2835 new->input = dst_discard;
2836 new->output = dst_discard_out;
2837
2838 new->dev = net->loopback_dev;
2839 netdev_hold(new->dev, &new->dev_tracker, GFP_ATOMIC);
2840
2841 rt->rt_is_input = ort->rt_is_input;
2842 rt->rt_iif = ort->rt_iif;
2843 rt->rt_pmtu = ort->rt_pmtu;
2844 rt->rt_mtu_locked = ort->rt_mtu_locked;
2845
2846 rt->rt_genid = rt_genid_ipv4(net);
2847 rt->rt_flags = ort->rt_flags;
2848 rt->rt_type = ort->rt_type;
2849 rt->rt_uses_gateway = ort->rt_uses_gateway;
2850 rt->rt_gw_family = ort->rt_gw_family;
2851 if (rt->rt_gw_family == AF_INET)
2852 rt->rt_gw4 = ort->rt_gw4;
2853 else if (rt->rt_gw_family == AF_INET6)
2854 rt->rt_gw6 = ort->rt_gw6;
2855 }
2856
2857 dst_release(dst_orig);
2858
2859 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2860}
2861
2862struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2863 const struct sock *sk)
2864{
2865 struct rtable *rt = __ip_route_output_key(net, flp4);
2866
2867 if (IS_ERR(rt))
2868 return rt;
2869
2870 if (flp4->flowi4_proto) {
2871 flp4->flowi4_oif = rt->dst.dev->ifindex;
2872 rt = dst_rtable(xfrm_lookup_route(net, &rt->dst,
2873 flowi4_to_flowi(flp4),
2874 sk, 0));
2875 }
2876
2877 return rt;
2878}
2879EXPORT_SYMBOL_GPL(ip_route_output_flow);
2880
2881/* called with rcu_read_lock held */
2882static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2883 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2884 struct sk_buff *skb, u32 portid, u32 seq,
2885 unsigned int flags)
2886{
2887 struct rtmsg *r;
2888 struct nlmsghdr *nlh;
2889 unsigned long expires = 0;
2890 u32 error;
2891 u32 metrics[RTAX_MAX];
2892
2893 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2894 if (!nlh)
2895 return -EMSGSIZE;
2896
2897 r = nlmsg_data(nlh);
2898 r->rtm_family = AF_INET;
2899 r->rtm_dst_len = 32;
2900 r->rtm_src_len = 0;
2901 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2902 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2903 if (nla_put_u32(skb, RTA_TABLE, table_id))
2904 goto nla_put_failure;
2905 r->rtm_type = rt->rt_type;
2906 r->rtm_scope = RT_SCOPE_UNIVERSE;
2907 r->rtm_protocol = RTPROT_UNSPEC;
2908 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2909 if (rt->rt_flags & RTCF_NOTIFY)
2910 r->rtm_flags |= RTM_F_NOTIFY;
2911 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2912 r->rtm_flags |= RTCF_DOREDIRECT;
2913
2914 if (nla_put_in_addr(skb, RTA_DST, dst))
2915 goto nla_put_failure;
2916 if (src) {
2917 r->rtm_src_len = 32;
2918 if (nla_put_in_addr(skb, RTA_SRC, src))
2919 goto nla_put_failure;
2920 }
2921 if (rt->dst.dev &&
2922 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2923 goto nla_put_failure;
2924 if (rt->dst.lwtstate &&
2925 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
2926 goto nla_put_failure;
2927#ifdef CONFIG_IP_ROUTE_CLASSID
2928 if (rt->dst.tclassid &&
2929 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2930 goto nla_put_failure;
2931#endif
2932 if (fl4 && !rt_is_input_route(rt) &&
2933 fl4->saddr != src) {
2934 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2935 goto nla_put_failure;
2936 }
2937 if (rt->rt_uses_gateway) {
2938 if (rt->rt_gw_family == AF_INET &&
2939 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2940 goto nla_put_failure;
2941 } else if (rt->rt_gw_family == AF_INET6) {
2942 int alen = sizeof(struct in6_addr);
2943 struct nlattr *nla;
2944 struct rtvia *via;
2945
2946 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2947 if (!nla)
2948 goto nla_put_failure;
2949
2950 via = nla_data(nla);
2951 via->rtvia_family = AF_INET6;
2952 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2953 }
2954 }
2955
2956 expires = rt->dst.expires;
2957 if (expires) {
2958 unsigned long now = jiffies;
2959
2960 if (time_before(now, expires))
2961 expires -= now;
2962 else
2963 expires = 0;
2964 }
2965
2966 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2967 if (rt->rt_pmtu && expires)
2968 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2969 if (rt->rt_mtu_locked && expires)
2970 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2971 if (rtnetlink_put_metrics(skb, metrics) < 0)
2972 goto nla_put_failure;
2973
2974 if (fl4) {
2975 if (fl4->flowi4_mark &&
2976 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2977 goto nla_put_failure;
2978
2979 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2980 nla_put_u32(skb, RTA_UID,
2981 from_kuid_munged(current_user_ns(),
2982 fl4->flowi4_uid)))
2983 goto nla_put_failure;
2984
2985 if (rt_is_input_route(rt)) {
2986#ifdef CONFIG_IP_MROUTE
2987 if (ipv4_is_multicast(dst) &&
2988 !ipv4_is_local_multicast(dst) &&
2989 IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) {
2990 int err = ipmr_get_route(net, skb,
2991 fl4->saddr, fl4->daddr,
2992 r, portid);
2993
2994 if (err <= 0) {
2995 if (err == 0)
2996 return 0;
2997 goto nla_put_failure;
2998 }
2999 } else
3000#endif
3001 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
3002 goto nla_put_failure;
3003 }
3004 }
3005
3006 error = rt->dst.error;
3007
3008 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
3009 goto nla_put_failure;
3010
3011 nlmsg_end(skb, nlh);
3012 return 0;
3013
3014nla_put_failure:
3015 nlmsg_cancel(skb, nlh);
3016 return -EMSGSIZE;
3017}
3018
3019static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3020 struct netlink_callback *cb, u32 table_id,
3021 struct fnhe_hash_bucket *bucket, int genid,
3022 int *fa_index, int fa_start, unsigned int flags)
3023{
3024 int i;
3025
3026 for (i = 0; i < FNHE_HASH_SIZE; i++) {
3027 struct fib_nh_exception *fnhe;
3028
3029 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3030 fnhe = rcu_dereference(fnhe->fnhe_next)) {
3031 struct rtable *rt;
3032 int err;
3033
3034 if (*fa_index < fa_start)
3035 goto next;
3036
3037 if (fnhe->fnhe_genid != genid)
3038 goto next;
3039
3040 if (fnhe->fnhe_expires &&
3041 time_after(jiffies, fnhe->fnhe_expires))
3042 goto next;
3043
3044 rt = rcu_dereference(fnhe->fnhe_rth_input);
3045 if (!rt)
3046 rt = rcu_dereference(fnhe->fnhe_rth_output);
3047 if (!rt)
3048 goto next;
3049
3050 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
3051 table_id, NULL, skb,
3052 NETLINK_CB(cb->skb).portid,
3053 cb->nlh->nlmsg_seq, flags);
3054 if (err)
3055 return err;
3056next:
3057 (*fa_index)++;
3058 }
3059 }
3060
3061 return 0;
3062}
3063
3064int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3065 u32 table_id, struct fib_info *fi,
3066 int *fa_index, int fa_start, unsigned int flags)
3067{
3068 struct net *net = sock_net(cb->skb->sk);
3069 int nhsel, genid = fnhe_genid(net);
3070
3071 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3072 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3073 struct fnhe_hash_bucket *bucket;
3074 int err;
3075
3076 if (nhc->nhc_flags & RTNH_F_DEAD)
3077 continue;
3078
3079 rcu_read_lock();
3080 bucket = rcu_dereference(nhc->nhc_exceptions);
3081 err = 0;
3082 if (bucket)
3083 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3084 genid, fa_index, fa_start,
3085 flags);
3086 rcu_read_unlock();
3087 if (err)
3088 return err;
3089 }
3090
3091 return 0;
3092}
3093
3094static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3095 u8 ip_proto, __be16 sport,
3096 __be16 dport)
3097{
3098 struct sk_buff *skb;
3099 struct iphdr *iph;
3100
3101 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3102 if (!skb)
3103 return NULL;
3104
3105 /* Reserve room for dummy headers, this skb can pass
3106 * through good chunk of routing engine.
3107 */
3108 skb_reset_mac_header(skb);
3109 skb_reset_network_header(skb);
3110 skb->protocol = htons(ETH_P_IP);
3111 iph = skb_put(skb, sizeof(struct iphdr));
3112 iph->protocol = ip_proto;
3113 iph->saddr = src;
3114 iph->daddr = dst;
3115 iph->version = 0x4;
3116 iph->frag_off = 0;
3117 iph->ihl = 0x5;
3118 skb_set_transport_header(skb, skb->len);
3119
3120 switch (iph->protocol) {
3121 case IPPROTO_UDP: {
3122 struct udphdr *udph;
3123
3124 udph = skb_put_zero(skb, sizeof(struct udphdr));
3125 udph->source = sport;
3126 udph->dest = dport;
3127 udph->len = htons(sizeof(struct udphdr));
3128 udph->check = 0;
3129 break;
3130 }
3131 case IPPROTO_TCP: {
3132 struct tcphdr *tcph;
3133
3134 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3135 tcph->source = sport;
3136 tcph->dest = dport;
3137 tcph->doff = sizeof(struct tcphdr) / 4;
3138 tcph->rst = 1;
3139 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3140 src, dst, 0);
3141 break;
3142 }
3143 case IPPROTO_ICMP: {
3144 struct icmphdr *icmph;
3145
3146 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3147 icmph->type = ICMP_ECHO;
3148 icmph->code = 0;
3149 }
3150 }
3151
3152 return skb;
3153}
3154
3155static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3156 const struct nlmsghdr *nlh,
3157 struct nlattr **tb,
3158 struct netlink_ext_ack *extack)
3159{
3160 struct rtmsg *rtm;
3161 int i, err;
3162
3163 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3164 NL_SET_ERR_MSG(extack,
3165 "ipv4: Invalid header for route get request");
3166 return -EINVAL;
3167 }
3168
3169 if (!netlink_strict_get_check(skb))
3170 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3171 rtm_ipv4_policy, extack);
3172
3173 rtm = nlmsg_data(nlh);
3174 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3175 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3176 rtm->rtm_table || rtm->rtm_protocol ||
3177 rtm->rtm_scope || rtm->rtm_type) {
3178 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3179 return -EINVAL;
3180 }
3181
3182 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3183 RTM_F_LOOKUP_TABLE |
3184 RTM_F_FIB_MATCH)) {
3185 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3186 return -EINVAL;
3187 }
3188
3189 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3190 rtm_ipv4_policy, extack);
3191 if (err)
3192 return err;
3193
3194 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3195 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3196 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3197 return -EINVAL;
3198 }
3199
3200 for (i = 0; i <= RTA_MAX; i++) {
3201 if (!tb[i])
3202 continue;
3203
3204 switch (i) {
3205 case RTA_IIF:
3206 case RTA_OIF:
3207 case RTA_SRC:
3208 case RTA_DST:
3209 case RTA_IP_PROTO:
3210 case RTA_SPORT:
3211 case RTA_DPORT:
3212 case RTA_MARK:
3213 case RTA_UID:
3214 break;
3215 default:
3216 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3217 return -EINVAL;
3218 }
3219 }
3220
3221 return 0;
3222}
3223
3224static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3225 struct netlink_ext_ack *extack)
3226{
3227 struct net *net = sock_net(in_skb->sk);
3228 struct nlattr *tb[RTA_MAX+1];
3229 u32 table_id = RT_TABLE_MAIN;
3230 __be16 sport = 0, dport = 0;
3231 struct fib_result res = {};
3232 u8 ip_proto = IPPROTO_UDP;
3233 struct rtable *rt = NULL;
3234 struct sk_buff *skb;
3235 struct rtmsg *rtm;
3236 struct flowi4 fl4 = {};
3237 __be32 dst = 0;
3238 __be32 src = 0;
3239 kuid_t uid;
3240 u32 iif;
3241 int err;
3242 int mark;
3243
3244 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3245 if (err < 0)
3246 return err;
3247
3248 rtm = nlmsg_data(nlh);
3249 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3250 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3251 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3252 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3253 if (tb[RTA_UID])
3254 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3255 else
3256 uid = (iif ? INVALID_UID : current_uid());
3257
3258 if (tb[RTA_IP_PROTO]) {
3259 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3260 &ip_proto, AF_INET, extack);
3261 if (err)
3262 return err;
3263 }
3264
3265 if (tb[RTA_SPORT])
3266 sport = nla_get_be16(tb[RTA_SPORT]);
3267
3268 if (tb[RTA_DPORT])
3269 dport = nla_get_be16(tb[RTA_DPORT]);
3270
3271 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3272 if (!skb)
3273 return -ENOBUFS;
3274
3275 fl4.daddr = dst;
3276 fl4.saddr = src;
3277 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK;
3278 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3279 fl4.flowi4_mark = mark;
3280 fl4.flowi4_uid = uid;
3281 if (sport)
3282 fl4.fl4_sport = sport;
3283 if (dport)
3284 fl4.fl4_dport = dport;
3285 fl4.flowi4_proto = ip_proto;
3286
3287 rcu_read_lock();
3288
3289 if (iif) {
3290 struct net_device *dev;
3291
3292 dev = dev_get_by_index_rcu(net, iif);
3293 if (!dev) {
3294 err = -ENODEV;
3295 goto errout_rcu;
3296 }
3297
3298 fl4.flowi4_iif = iif; /* for rt_fill_info */
3299 skb->dev = dev;
3300 skb->mark = mark;
3301 err = ip_route_input_rcu(skb, dst, src,
3302 rtm->rtm_tos & IPTOS_RT_MASK, dev,
3303 &res);
3304
3305 rt = skb_rtable(skb);
3306 if (err == 0 && rt->dst.error)
3307 err = -rt->dst.error;
3308 } else {
3309 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3310 skb->dev = net->loopback_dev;
3311 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3312 err = 0;
3313 if (IS_ERR(rt))
3314 err = PTR_ERR(rt);
3315 else
3316 skb_dst_set(skb, &rt->dst);
3317 }
3318
3319 if (err)
3320 goto errout_rcu;
3321
3322 if (rtm->rtm_flags & RTM_F_NOTIFY)
3323 rt->rt_flags |= RTCF_NOTIFY;
3324
3325 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3326 table_id = res.table ? res.table->tb_id : 0;
3327
3328 /* reset skb for netlink reply msg */
3329 skb_trim(skb, 0);
3330 skb_reset_network_header(skb);
3331 skb_reset_transport_header(skb);
3332 skb_reset_mac_header(skb);
3333
3334 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3335 struct fib_rt_info fri;
3336
3337 if (!res.fi) {
3338 err = fib_props[res.type].error;
3339 if (!err)
3340 err = -EHOSTUNREACH;
3341 goto errout_rcu;
3342 }
3343 fri.fi = res.fi;
3344 fri.tb_id = table_id;
3345 fri.dst = res.prefix;
3346 fri.dst_len = res.prefixlen;
3347 fri.dscp = inet_dsfield_to_dscp(fl4.flowi4_tos);
3348 fri.type = rt->rt_type;
3349 fri.offload = 0;
3350 fri.trap = 0;
3351 fri.offload_failed = 0;
3352 if (res.fa_head) {
3353 struct fib_alias *fa;
3354
3355 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3356 u8 slen = 32 - fri.dst_len;
3357
3358 if (fa->fa_slen == slen &&
3359 fa->tb_id == fri.tb_id &&
3360 fa->fa_dscp == fri.dscp &&
3361 fa->fa_info == res.fi &&
3362 fa->fa_type == fri.type) {
3363 fri.offload = READ_ONCE(fa->offload);
3364 fri.trap = READ_ONCE(fa->trap);
3365 fri.offload_failed =
3366 READ_ONCE(fa->offload_failed);
3367 break;
3368 }
3369 }
3370 }
3371 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3372 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3373 } else {
3374 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3375 NETLINK_CB(in_skb).portid,
3376 nlh->nlmsg_seq, 0);
3377 }
3378 if (err < 0)
3379 goto errout_rcu;
3380
3381 rcu_read_unlock();
3382
3383 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3384
3385errout_free:
3386 return err;
3387errout_rcu:
3388 rcu_read_unlock();
3389 kfree_skb(skb);
3390 goto errout_free;
3391}
3392
3393void ip_rt_multicast_event(struct in_device *in_dev)
3394{
3395 rt_cache_flush(dev_net(in_dev->dev));
3396}
3397
3398#ifdef CONFIG_SYSCTL
3399static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3400static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3401static int ip_rt_gc_elasticity __read_mostly = 8;
3402static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3403
3404static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3405 void *buffer, size_t *lenp, loff_t *ppos)
3406{
3407 struct net *net = (struct net *)__ctl->extra1;
3408
3409 if (write) {
3410 rt_cache_flush(net);
3411 fnhe_genid_bump(net);
3412 return 0;
3413 }
3414
3415 return -EINVAL;
3416}
3417
3418static struct ctl_table ipv4_route_table[] = {
3419 {
3420 .procname = "gc_thresh",
3421 .data = &ipv4_dst_ops.gc_thresh,
3422 .maxlen = sizeof(int),
3423 .mode = 0644,
3424 .proc_handler = proc_dointvec,
3425 },
3426 {
3427 .procname = "max_size",
3428 .data = &ip_rt_max_size,
3429 .maxlen = sizeof(int),
3430 .mode = 0644,
3431 .proc_handler = proc_dointvec,
3432 },
3433 {
3434 /* Deprecated. Use gc_min_interval_ms */
3435
3436 .procname = "gc_min_interval",
3437 .data = &ip_rt_gc_min_interval,
3438 .maxlen = sizeof(int),
3439 .mode = 0644,
3440 .proc_handler = proc_dointvec_jiffies,
3441 },
3442 {
3443 .procname = "gc_min_interval_ms",
3444 .data = &ip_rt_gc_min_interval,
3445 .maxlen = sizeof(int),
3446 .mode = 0644,
3447 .proc_handler = proc_dointvec_ms_jiffies,
3448 },
3449 {
3450 .procname = "gc_timeout",
3451 .data = &ip_rt_gc_timeout,
3452 .maxlen = sizeof(int),
3453 .mode = 0644,
3454 .proc_handler = proc_dointvec_jiffies,
3455 },
3456 {
3457 .procname = "gc_interval",
3458 .data = &ip_rt_gc_interval,
3459 .maxlen = sizeof(int),
3460 .mode = 0644,
3461 .proc_handler = proc_dointvec_jiffies,
3462 },
3463 {
3464 .procname = "redirect_load",
3465 .data = &ip_rt_redirect_load,
3466 .maxlen = sizeof(int),
3467 .mode = 0644,
3468 .proc_handler = proc_dointvec,
3469 },
3470 {
3471 .procname = "redirect_number",
3472 .data = &ip_rt_redirect_number,
3473 .maxlen = sizeof(int),
3474 .mode = 0644,
3475 .proc_handler = proc_dointvec,
3476 },
3477 {
3478 .procname = "redirect_silence",
3479 .data = &ip_rt_redirect_silence,
3480 .maxlen = sizeof(int),
3481 .mode = 0644,
3482 .proc_handler = proc_dointvec,
3483 },
3484 {
3485 .procname = "error_cost",
3486 .data = &ip_rt_error_cost,
3487 .maxlen = sizeof(int),
3488 .mode = 0644,
3489 .proc_handler = proc_dointvec,
3490 },
3491 {
3492 .procname = "error_burst",
3493 .data = &ip_rt_error_burst,
3494 .maxlen = sizeof(int),
3495 .mode = 0644,
3496 .proc_handler = proc_dointvec,
3497 },
3498 {
3499 .procname = "gc_elasticity",
3500 .data = &ip_rt_gc_elasticity,
3501 .maxlen = sizeof(int),
3502 .mode = 0644,
3503 .proc_handler = proc_dointvec,
3504 },
3505 { }
3506};
3507
3508static const char ipv4_route_flush_procname[] = "flush";
3509
3510static struct ctl_table ipv4_route_netns_table[] = {
3511 {
3512 .procname = ipv4_route_flush_procname,
3513 .maxlen = sizeof(int),
3514 .mode = 0200,
3515 .proc_handler = ipv4_sysctl_rtcache_flush,
3516 },
3517 {
3518 .procname = "min_pmtu",
3519 .data = &init_net.ipv4.ip_rt_min_pmtu,
3520 .maxlen = sizeof(int),
3521 .mode = 0644,
3522 .proc_handler = proc_dointvec_minmax,
3523 .extra1 = &ip_min_valid_pmtu,
3524 },
3525 {
3526 .procname = "mtu_expires",
3527 .data = &init_net.ipv4.ip_rt_mtu_expires,
3528 .maxlen = sizeof(int),
3529 .mode = 0644,
3530 .proc_handler = proc_dointvec_jiffies,
3531 },
3532 {
3533 .procname = "min_adv_mss",
3534 .data = &init_net.ipv4.ip_rt_min_advmss,
3535 .maxlen = sizeof(int),
3536 .mode = 0644,
3537 .proc_handler = proc_dointvec,
3538 },
3539 { },
3540};
3541
3542static __net_init int sysctl_route_net_init(struct net *net)
3543{
3544 struct ctl_table *tbl;
3545 size_t table_size = ARRAY_SIZE(ipv4_route_netns_table);
3546
3547 tbl = ipv4_route_netns_table;
3548 if (!net_eq(net, &init_net)) {
3549 int i;
3550
3551 tbl = kmemdup(tbl, sizeof(ipv4_route_netns_table), GFP_KERNEL);
3552 if (!tbl)
3553 goto err_dup;
3554
3555 /* Don't export non-whitelisted sysctls to unprivileged users */
3556 if (net->user_ns != &init_user_ns) {
3557 if (tbl[0].procname != ipv4_route_flush_procname) {
3558 tbl[0].procname = NULL;
3559 table_size = 0;
3560 }
3561 }
3562
3563 /* Update the variables to point into the current struct net
3564 * except for the first element flush
3565 */
3566 for (i = 1; i < ARRAY_SIZE(ipv4_route_netns_table) - 1; i++)
3567 tbl[i].data += (void *)net - (void *)&init_net;
3568 }
3569 tbl[0].extra1 = net;
3570
3571 net->ipv4.route_hdr = register_net_sysctl_sz(net, "net/ipv4/route",
3572 tbl, table_size);
3573 if (!net->ipv4.route_hdr)
3574 goto err_reg;
3575 return 0;
3576
3577err_reg:
3578 if (tbl != ipv4_route_netns_table)
3579 kfree(tbl);
3580err_dup:
3581 return -ENOMEM;
3582}
3583
3584static __net_exit void sysctl_route_net_exit(struct net *net)
3585{
3586 struct ctl_table *tbl;
3587
3588 tbl = net->ipv4.route_hdr->ctl_table_arg;
3589 unregister_net_sysctl_table(net->ipv4.route_hdr);
3590 BUG_ON(tbl == ipv4_route_netns_table);
3591 kfree(tbl);
3592}
3593
3594static __net_initdata struct pernet_operations sysctl_route_ops = {
3595 .init = sysctl_route_net_init,
3596 .exit = sysctl_route_net_exit,
3597};
3598#endif
3599
3600static __net_init int netns_ip_rt_init(struct net *net)
3601{
3602 /* Set default value for namespaceified sysctls */
3603 net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU;
3604 net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES;
3605 net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS;
3606 return 0;
3607}
3608
3609static struct pernet_operations __net_initdata ip_rt_ops = {
3610 .init = netns_ip_rt_init,
3611};
3612
3613static __net_init int rt_genid_init(struct net *net)
3614{
3615 atomic_set(&net->ipv4.rt_genid, 0);
3616 atomic_set(&net->fnhe_genid, 0);
3617 atomic_set(&net->ipv4.dev_addr_genid, get_random_u32());
3618 return 0;
3619}
3620
3621static __net_initdata struct pernet_operations rt_genid_ops = {
3622 .init = rt_genid_init,
3623};
3624
3625static int __net_init ipv4_inetpeer_init(struct net *net)
3626{
3627 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3628
3629 if (!bp)
3630 return -ENOMEM;
3631 inet_peer_base_init(bp);
3632 net->ipv4.peers = bp;
3633 return 0;
3634}
3635
3636static void __net_exit ipv4_inetpeer_exit(struct net *net)
3637{
3638 struct inet_peer_base *bp = net->ipv4.peers;
3639
3640 net->ipv4.peers = NULL;
3641 inetpeer_invalidate_tree(bp);
3642 kfree(bp);
3643}
3644
3645static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3646 .init = ipv4_inetpeer_init,
3647 .exit = ipv4_inetpeer_exit,
3648};
3649
3650#ifdef CONFIG_IP_ROUTE_CLASSID
3651struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3652#endif /* CONFIG_IP_ROUTE_CLASSID */
3653
3654int __init ip_rt_init(void)
3655{
3656 void *idents_hash;
3657 int cpu;
3658
3659 /* For modern hosts, this will use 2 MB of memory */
3660 idents_hash = alloc_large_system_hash("IP idents",
3661 sizeof(*ip_idents) + sizeof(*ip_tstamps),
3662 0,
3663 16, /* one bucket per 64 KB */
3664 HASH_ZERO,
3665 NULL,
3666 &ip_idents_mask,
3667 2048,
3668 256*1024);
3669
3670 ip_idents = idents_hash;
3671
3672 get_random_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
3673
3674 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3675
3676 for_each_possible_cpu(cpu) {
3677 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3678
3679 INIT_LIST_HEAD(&ul->head);
3680 INIT_LIST_HEAD(&ul->quarantine);
3681 spin_lock_init(&ul->lock);
3682 }
3683#ifdef CONFIG_IP_ROUTE_CLASSID
3684 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3685 if (!ip_rt_acct)
3686 panic("IP: failed to allocate ip_rt_acct\n");
3687#endif
3688
3689 ipv4_dst_ops.kmem_cachep = KMEM_CACHE(rtable,
3690 SLAB_HWCACHE_ALIGN | SLAB_PANIC);
3691
3692 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3693
3694 if (dst_entries_init(&ipv4_dst_ops) < 0)
3695 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3696
3697 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3698 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3699
3700 ipv4_dst_ops.gc_thresh = ~0;
3701 ip_rt_max_size = INT_MAX;
3702
3703 devinet_init();
3704 ip_fib_init();
3705
3706 if (ip_rt_proc_init())
3707 pr_err("Unable to create route proc files\n");
3708#ifdef CONFIG_XFRM
3709 xfrm_init();
3710 xfrm4_init();
3711#endif
3712 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3713 RTNL_FLAG_DOIT_UNLOCKED);
3714
3715#ifdef CONFIG_SYSCTL
3716 register_pernet_subsys(&sysctl_route_ops);
3717#endif
3718 register_pernet_subsys(&ip_rt_ops);
3719 register_pernet_subsys(&rt_genid_ops);
3720 register_pernet_subsys(&ipv4_inetpeer_ops);
3721 return 0;
3722}
3723
3724#ifdef CONFIG_SYSCTL
3725/*
3726 * We really need to sanitize the damn ipv4 init order, then all
3727 * this nonsense will go away.
3728 */
3729void __init ip_static_sysctl_init(void)
3730{
3731 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3732}
3733#endif