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proc: convert everything to "struct proc_ops"
[mirror_ubuntu-jammy-kernel.git] / net / ipv4 / route.c
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
120 static int ip_rt_max_size;
121 static int ip_rt_redirect_number __read_mostly = 9;
122 static int ip_rt_redirect_load __read_mostly = HZ / 50;
123 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
124 static int ip_rt_error_cost __read_mostly = HZ;
125 static int ip_rt_error_burst __read_mostly = 5 * HZ;
126 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
127 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
128 static int ip_rt_min_advmss __read_mostly = 256;
129
130 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
131
132 /*
133 * Interface to generic destination cache.
134 */
135
136 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
137 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
138 static unsigned int ipv4_mtu(const struct dst_entry *dst);
139 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
140 static void ipv4_link_failure(struct sk_buff *skb);
141 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
142 struct sk_buff *skb, u32 mtu,
143 bool confirm_neigh);
144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb);
146 static void ipv4_dst_destroy(struct dst_entry *dst);
147
148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
149 {
150 WARN_ON(1);
151 return NULL;
152 }
153
154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
155 struct sk_buff *skb,
156 const void *daddr);
157 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
158
159 static 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
177 const __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 };
195 EXPORT_SYMBOL(ip_tos2prio);
196
197 static 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
201 static 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
208 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
209 {
210 ++*pos;
211 return NULL;
212 }
213
214 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
215 {
216 }
217
218 static 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
228 static 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
235 static int rt_cache_seq_open(struct inode *inode, struct file *file)
236 {
237 return seq_open(file, &rt_cache_seq_ops);
238 }
239
240 static 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
248 static 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
264 static 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
279 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
280 {
281
282 }
283
284 static 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
318 static 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
326 static int rt_cpu_seq_open(struct inode *inode, struct file *file)
327 {
328 return seq_open(file, &rt_cpu_seq_ops);
329 }
330
331 static 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
339 static 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
364 static 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
387 err3:
388 remove_proc_entry("rt_cache", net->proc_net_stat);
389 #endif
390 err2:
391 remove_proc_entry("rt_cache", net->proc_net);
392 err1:
393 return -ENOMEM;
394 }
395
396 static 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
405 static 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
410 static int __init ip_rt_proc_init(void)
411 {
412 return register_pernet_subsys(&ip_rt_proc_ops);
413 }
414
415 #else
416 static inline int ip_rt_proc_init(void)
417 {
418 return 0;
419 }
420 #endif /* CONFIG_PROC_FS */
421
422 static 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
427 void rt_cache_flush(struct net *net)
428 {
429 rt_genid_bump_ipv4(net);
430 }
431
432 static 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
461 static 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
481 static atomic_t *ip_idents __read_mostly;
482 static 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 */
488 u32 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 new, delta = 0;
495
496 if (old != now && cmpxchg(p_tstamp, old, now) == old)
497 delta = prandom_u32_max(now - old);
498
499 /* Do not use atomic_add_return() as it makes UBSAN unhappy */
500 do {
501 old = (u32)atomic_read(p_id);
502 new = old + delta + segs;
503 } while (atomic_cmpxchg(p_id, old, new) != old);
504
505 return new - segs;
506 }
507 EXPORT_SYMBOL(ip_idents_reserve);
508
509 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
510 {
511 u32 hash, id;
512
513 /* Note the following code is not safe, but this is okay. */
514 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
515 get_random_bytes(&net->ipv4.ip_id_key,
516 sizeof(net->ipv4.ip_id_key));
517
518 hash = siphash_3u32((__force u32)iph->daddr,
519 (__force u32)iph->saddr,
520 iph->protocol,
521 &net->ipv4.ip_id_key);
522 id = ip_idents_reserve(hash, segs);
523 iph->id = htons(id);
524 }
525 EXPORT_SYMBOL(__ip_select_ident);
526
527 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
528 const struct sock *sk,
529 const struct iphdr *iph,
530 int oif, u8 tos,
531 u8 prot, u32 mark, int flow_flags)
532 {
533 if (sk) {
534 const struct inet_sock *inet = inet_sk(sk);
535
536 oif = sk->sk_bound_dev_if;
537 mark = sk->sk_mark;
538 tos = RT_CONN_FLAGS(sk);
539 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
540 }
541 flowi4_init_output(fl4, oif, mark, tos,
542 RT_SCOPE_UNIVERSE, prot,
543 flow_flags,
544 iph->daddr, iph->saddr, 0, 0,
545 sock_net_uid(net, sk));
546 }
547
548 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
549 const struct sock *sk)
550 {
551 const struct net *net = dev_net(skb->dev);
552 const struct iphdr *iph = ip_hdr(skb);
553 int oif = skb->dev->ifindex;
554 u8 tos = RT_TOS(iph->tos);
555 u8 prot = iph->protocol;
556 u32 mark = skb->mark;
557
558 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
559 }
560
561 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
562 {
563 const struct inet_sock *inet = inet_sk(sk);
564 const struct ip_options_rcu *inet_opt;
565 __be32 daddr = inet->inet_daddr;
566
567 rcu_read_lock();
568 inet_opt = rcu_dereference(inet->inet_opt);
569 if (inet_opt && inet_opt->opt.srr)
570 daddr = inet_opt->opt.faddr;
571 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
572 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
573 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
574 inet_sk_flowi_flags(sk),
575 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
576 rcu_read_unlock();
577 }
578
579 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
580 const struct sk_buff *skb)
581 {
582 if (skb)
583 build_skb_flow_key(fl4, skb, sk);
584 else
585 build_sk_flow_key(fl4, sk);
586 }
587
588 static DEFINE_SPINLOCK(fnhe_lock);
589
590 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
591 {
592 struct rtable *rt;
593
594 rt = rcu_dereference(fnhe->fnhe_rth_input);
595 if (rt) {
596 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
597 dst_dev_put(&rt->dst);
598 dst_release(&rt->dst);
599 }
600 rt = rcu_dereference(fnhe->fnhe_rth_output);
601 if (rt) {
602 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
603 dst_dev_put(&rt->dst);
604 dst_release(&rt->dst);
605 }
606 }
607
608 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
609 {
610 struct fib_nh_exception *fnhe, *oldest;
611
612 oldest = rcu_dereference(hash->chain);
613 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
614 fnhe = rcu_dereference(fnhe->fnhe_next)) {
615 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
616 oldest = fnhe;
617 }
618 fnhe_flush_routes(oldest);
619 return oldest;
620 }
621
622 static inline u32 fnhe_hashfun(__be32 daddr)
623 {
624 static u32 fnhe_hashrnd __read_mostly;
625 u32 hval;
626
627 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
628 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);
629 return hash_32(hval, FNHE_HASH_SHIFT);
630 }
631
632 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
633 {
634 rt->rt_pmtu = fnhe->fnhe_pmtu;
635 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
636 rt->dst.expires = fnhe->fnhe_expires;
637
638 if (fnhe->fnhe_gw) {
639 rt->rt_flags |= RTCF_REDIRECTED;
640 rt->rt_uses_gateway = 1;
641 rt->rt_gw_family = AF_INET;
642 rt->rt_gw4 = fnhe->fnhe_gw;
643 }
644 }
645
646 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
647 __be32 gw, u32 pmtu, bool lock,
648 unsigned long expires)
649 {
650 struct fnhe_hash_bucket *hash;
651 struct fib_nh_exception *fnhe;
652 struct rtable *rt;
653 u32 genid, hval;
654 unsigned int i;
655 int depth;
656
657 genid = fnhe_genid(dev_net(nhc->nhc_dev));
658 hval = fnhe_hashfun(daddr);
659
660 spin_lock_bh(&fnhe_lock);
661
662 hash = rcu_dereference(nhc->nhc_exceptions);
663 if (!hash) {
664 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
665 if (!hash)
666 goto out_unlock;
667 rcu_assign_pointer(nhc->nhc_exceptions, hash);
668 }
669
670 hash += hval;
671
672 depth = 0;
673 for (fnhe = rcu_dereference(hash->chain); fnhe;
674 fnhe = rcu_dereference(fnhe->fnhe_next)) {
675 if (fnhe->fnhe_daddr == daddr)
676 break;
677 depth++;
678 }
679
680 if (fnhe) {
681 if (fnhe->fnhe_genid != genid)
682 fnhe->fnhe_genid = genid;
683 if (gw)
684 fnhe->fnhe_gw = gw;
685 if (pmtu) {
686 fnhe->fnhe_pmtu = pmtu;
687 fnhe->fnhe_mtu_locked = lock;
688 }
689 fnhe->fnhe_expires = max(1UL, expires);
690 /* Update all cached dsts too */
691 rt = rcu_dereference(fnhe->fnhe_rth_input);
692 if (rt)
693 fill_route_from_fnhe(rt, fnhe);
694 rt = rcu_dereference(fnhe->fnhe_rth_output);
695 if (rt)
696 fill_route_from_fnhe(rt, fnhe);
697 } else {
698 if (depth > FNHE_RECLAIM_DEPTH)
699 fnhe = fnhe_oldest(hash);
700 else {
701 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
702 if (!fnhe)
703 goto out_unlock;
704
705 fnhe->fnhe_next = hash->chain;
706 rcu_assign_pointer(hash->chain, fnhe);
707 }
708 fnhe->fnhe_genid = genid;
709 fnhe->fnhe_daddr = daddr;
710 fnhe->fnhe_gw = gw;
711 fnhe->fnhe_pmtu = pmtu;
712 fnhe->fnhe_mtu_locked = lock;
713 fnhe->fnhe_expires = max(1UL, expires);
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 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
726 rt = rcu_dereference(*prt);
727 if (rt)
728 rt->dst.obsolete = DST_OBSOLETE_KILL;
729 }
730 }
731
732 fnhe->fnhe_stamp = jiffies;
733
734 out_unlock:
735 spin_unlock_bh(&fnhe_lock);
736 }
737
738 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
739 bool kill_route)
740 {
741 __be32 new_gw = icmp_hdr(skb)->un.gateway;
742 __be32 old_gw = ip_hdr(skb)->saddr;
743 struct net_device *dev = skb->dev;
744 struct in_device *in_dev;
745 struct fib_result res;
746 struct neighbour *n;
747 struct net *net;
748
749 switch (icmp_hdr(skb)->code & 7) {
750 case ICMP_REDIR_NET:
751 case ICMP_REDIR_NETTOS:
752 case ICMP_REDIR_HOST:
753 case ICMP_REDIR_HOSTTOS:
754 break;
755
756 default:
757 return;
758 }
759
760 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
761 return;
762
763 in_dev = __in_dev_get_rcu(dev);
764 if (!in_dev)
765 return;
766
767 net = dev_net(dev);
768 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
769 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
770 ipv4_is_zeronet(new_gw))
771 goto reject_redirect;
772
773 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
774 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
775 goto reject_redirect;
776 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
777 goto reject_redirect;
778 } else {
779 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
780 goto reject_redirect;
781 }
782
783 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
784 if (!n)
785 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
786 if (!IS_ERR(n)) {
787 if (!(n->nud_state & NUD_VALID)) {
788 neigh_event_send(n, NULL);
789 } else {
790 if (fib_lookup(net, fl4, &res, 0) == 0) {
791 struct fib_nh_common *nhc = FIB_RES_NHC(res);
792
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
805 reject_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
821 static 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
838 static 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
872 void 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->rate_tokens == 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 }
935 out_put_peer:
936 inet_putpeer(peer);
937 }
938
939 static 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
1011 out: kfree_skb(skb);
1012 return 0;
1013 }
1014
1015 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1016 {
1017 struct dst_entry *dst = &rt->dst;
1018 u32 old_mtu = ipv4_mtu(dst);
1019 struct fib_result res;
1020 bool lock = false;
1021
1022 if (ip_mtu_locked(dst))
1023 return;
1024
1025 if (old_mtu < mtu)
1026 return;
1027
1028 if (mtu < ip_rt_min_pmtu) {
1029 lock = true;
1030 mtu = min(old_mtu, ip_rt_min_pmtu);
1031 }
1032
1033 if (rt->rt_pmtu == mtu && !lock &&
1034 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1035 return;
1036
1037 rcu_read_lock();
1038 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) {
1039 struct fib_nh_common *nhc = FIB_RES_NHC(res);
1040
1041 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1042 jiffies + ip_rt_mtu_expires);
1043 }
1044 rcu_read_unlock();
1045 }
1046
1047 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1048 struct sk_buff *skb, u32 mtu,
1049 bool confirm_neigh)
1050 {
1051 struct rtable *rt = (struct rtable *) dst;
1052 struct flowi4 fl4;
1053
1054 ip_rt_build_flow_key(&fl4, sk, skb);
1055 __ip_rt_update_pmtu(rt, &fl4, mtu);
1056 }
1057
1058 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1059 int oif, u8 protocol)
1060 {
1061 const struct iphdr *iph = (const struct iphdr *) skb->data;
1062 struct flowi4 fl4;
1063 struct rtable *rt;
1064 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1065
1066 __build_flow_key(net, &fl4, NULL, iph, oif,
1067 RT_TOS(iph->tos), protocol, mark, 0);
1068 rt = __ip_route_output_key(net, &fl4);
1069 if (!IS_ERR(rt)) {
1070 __ip_rt_update_pmtu(rt, &fl4, mtu);
1071 ip_rt_put(rt);
1072 }
1073 }
1074 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1075
1076 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1077 {
1078 const struct iphdr *iph = (const struct iphdr *) skb->data;
1079 struct flowi4 fl4;
1080 struct rtable *rt;
1081
1082 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1083
1084 if (!fl4.flowi4_mark)
1085 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1086
1087 rt = __ip_route_output_key(sock_net(sk), &fl4);
1088 if (!IS_ERR(rt)) {
1089 __ip_rt_update_pmtu(rt, &fl4, mtu);
1090 ip_rt_put(rt);
1091 }
1092 }
1093
1094 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1095 {
1096 const struct iphdr *iph = (const struct iphdr *) skb->data;
1097 struct flowi4 fl4;
1098 struct rtable *rt;
1099 struct dst_entry *odst = NULL;
1100 bool new = false;
1101 struct net *net = sock_net(sk);
1102
1103 bh_lock_sock(sk);
1104
1105 if (!ip_sk_accept_pmtu(sk))
1106 goto out;
1107
1108 odst = sk_dst_get(sk);
1109
1110 if (sock_owned_by_user(sk) || !odst) {
1111 __ipv4_sk_update_pmtu(skb, sk, mtu);
1112 goto out;
1113 }
1114
1115 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1116
1117 rt = (struct rtable *)odst;
1118 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1119 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1120 if (IS_ERR(rt))
1121 goto out;
1122
1123 new = true;
1124 }
1125
1126 __ip_rt_update_pmtu((struct rtable *) xfrm_dst_path(&rt->dst), &fl4, mtu);
1127
1128 if (!dst_check(&rt->dst, 0)) {
1129 if (new)
1130 dst_release(&rt->dst);
1131
1132 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1133 if (IS_ERR(rt))
1134 goto out;
1135
1136 new = true;
1137 }
1138
1139 if (new)
1140 sk_dst_set(sk, &rt->dst);
1141
1142 out:
1143 bh_unlock_sock(sk);
1144 dst_release(odst);
1145 }
1146 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1147
1148 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1149 int oif, u8 protocol)
1150 {
1151 const struct iphdr *iph = (const struct iphdr *) skb->data;
1152 struct flowi4 fl4;
1153 struct rtable *rt;
1154
1155 __build_flow_key(net, &fl4, NULL, iph, oif,
1156 RT_TOS(iph->tos), protocol, 0, 0);
1157 rt = __ip_route_output_key(net, &fl4);
1158 if (!IS_ERR(rt)) {
1159 __ip_do_redirect(rt, skb, &fl4, false);
1160 ip_rt_put(rt);
1161 }
1162 }
1163 EXPORT_SYMBOL_GPL(ipv4_redirect);
1164
1165 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1166 {
1167 const struct iphdr *iph = (const struct iphdr *) skb->data;
1168 struct flowi4 fl4;
1169 struct rtable *rt;
1170 struct net *net = sock_net(sk);
1171
1172 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1173 rt = __ip_route_output_key(net, &fl4);
1174 if (!IS_ERR(rt)) {
1175 __ip_do_redirect(rt, skb, &fl4, false);
1176 ip_rt_put(rt);
1177 }
1178 }
1179 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1180
1181 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
1182 {
1183 struct rtable *rt = (struct rtable *) dst;
1184
1185 /* All IPV4 dsts are created with ->obsolete set to the value
1186 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1187 * into this function always.
1188 *
1189 * When a PMTU/redirect information update invalidates a route,
1190 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1191 * DST_OBSOLETE_DEAD.
1192 */
1193 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1194 return NULL;
1195 return dst;
1196 }
1197
1198 static void ipv4_send_dest_unreach(struct sk_buff *skb)
1199 {
1200 struct ip_options opt;
1201 int res;
1202
1203 /* Recompile ip options since IPCB may not be valid anymore.
1204 * Also check we have a reasonable ipv4 header.
1205 */
1206 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1207 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1208 return;
1209
1210 memset(&opt, 0, sizeof(opt));
1211 if (ip_hdr(skb)->ihl > 5) {
1212 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1213 return;
1214 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1215
1216 rcu_read_lock();
1217 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL);
1218 rcu_read_unlock();
1219
1220 if (res)
1221 return;
1222 }
1223 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1224 }
1225
1226 static void ipv4_link_failure(struct sk_buff *skb)
1227 {
1228 struct rtable *rt;
1229
1230 ipv4_send_dest_unreach(skb);
1231
1232 rt = skb_rtable(skb);
1233 if (rt)
1234 dst_set_expires(&rt->dst, 0);
1235 }
1236
1237 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1238 {
1239 pr_debug("%s: %pI4 -> %pI4, %s\n",
1240 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1241 skb->dev ? skb->dev->name : "?");
1242 kfree_skb(skb);
1243 WARN_ON(1);
1244 return 0;
1245 }
1246
1247 /*
1248 We do not cache source address of outgoing interface,
1249 because it is used only by IP RR, TS and SRR options,
1250 so that it out of fast path.
1251
1252 BTW remember: "addr" is allowed to be not aligned
1253 in IP options!
1254 */
1255
1256 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1257 {
1258 __be32 src;
1259
1260 if (rt_is_output_route(rt))
1261 src = ip_hdr(skb)->saddr;
1262 else {
1263 struct fib_result res;
1264 struct iphdr *iph = ip_hdr(skb);
1265 struct flowi4 fl4 = {
1266 .daddr = iph->daddr,
1267 .saddr = iph->saddr,
1268 .flowi4_tos = RT_TOS(iph->tos),
1269 .flowi4_oif = rt->dst.dev->ifindex,
1270 .flowi4_iif = skb->dev->ifindex,
1271 .flowi4_mark = skb->mark,
1272 };
1273
1274 rcu_read_lock();
1275 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1276 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1277 else
1278 src = inet_select_addr(rt->dst.dev,
1279 rt_nexthop(rt, iph->daddr),
1280 RT_SCOPE_UNIVERSE);
1281 rcu_read_unlock();
1282 }
1283 memcpy(addr, &src, 4);
1284 }
1285
1286 #ifdef CONFIG_IP_ROUTE_CLASSID
1287 static void set_class_tag(struct rtable *rt, u32 tag)
1288 {
1289 if (!(rt->dst.tclassid & 0xFFFF))
1290 rt->dst.tclassid |= tag & 0xFFFF;
1291 if (!(rt->dst.tclassid & 0xFFFF0000))
1292 rt->dst.tclassid |= tag & 0xFFFF0000;
1293 }
1294 #endif
1295
1296 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1297 {
1298 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1299 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1300 ip_rt_min_advmss);
1301
1302 return min(advmss, IPV4_MAX_PMTU - header_size);
1303 }
1304
1305 static unsigned int ipv4_mtu(const struct dst_entry *dst)
1306 {
1307 const struct rtable *rt = (const struct rtable *) dst;
1308 unsigned int mtu = rt->rt_pmtu;
1309
1310 if (!mtu || time_after_eq(jiffies, rt->dst.expires))
1311 mtu = dst_metric_raw(dst, RTAX_MTU);
1312
1313 if (mtu)
1314 return mtu;
1315
1316 mtu = READ_ONCE(dst->dev->mtu);
1317
1318 if (unlikely(ip_mtu_locked(dst))) {
1319 if (rt->rt_uses_gateway && mtu > 576)
1320 mtu = 576;
1321 }
1322
1323 mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
1324
1325 return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
1326 }
1327
1328 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1329 {
1330 struct fnhe_hash_bucket *hash;
1331 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1332 u32 hval = fnhe_hashfun(daddr);
1333
1334 spin_lock_bh(&fnhe_lock);
1335
1336 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1337 lockdep_is_held(&fnhe_lock));
1338 hash += hval;
1339
1340 fnhe_p = &hash->chain;
1341 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1342 while (fnhe) {
1343 if (fnhe->fnhe_daddr == daddr) {
1344 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1345 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1346 /* set fnhe_daddr to 0 to ensure it won't bind with
1347 * new dsts in rt_bind_exception().
1348 */
1349 fnhe->fnhe_daddr = 0;
1350 fnhe_flush_routes(fnhe);
1351 kfree_rcu(fnhe, rcu);
1352 break;
1353 }
1354 fnhe_p = &fnhe->fnhe_next;
1355 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1356 lockdep_is_held(&fnhe_lock));
1357 }
1358
1359 spin_unlock_bh(&fnhe_lock);
1360 }
1361
1362 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1363 __be32 daddr)
1364 {
1365 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1366 struct fib_nh_exception *fnhe;
1367 u32 hval;
1368
1369 if (!hash)
1370 return NULL;
1371
1372 hval = fnhe_hashfun(daddr);
1373
1374 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1375 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1376 if (fnhe->fnhe_daddr == daddr) {
1377 if (fnhe->fnhe_expires &&
1378 time_after(jiffies, fnhe->fnhe_expires)) {
1379 ip_del_fnhe(nhc, daddr);
1380 break;
1381 }
1382 return fnhe;
1383 }
1384 }
1385 return NULL;
1386 }
1387
1388 /* MTU selection:
1389 * 1. mtu on route is locked - use it
1390 * 2. mtu from nexthop exception
1391 * 3. mtu from egress device
1392 */
1393
1394 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1395 {
1396 struct fib_nh_common *nhc = res->nhc;
1397 struct net_device *dev = nhc->nhc_dev;
1398 struct fib_info *fi = res->fi;
1399 u32 mtu = 0;
1400
1401 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1402 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1403 mtu = fi->fib_mtu;
1404
1405 if (likely(!mtu)) {
1406 struct fib_nh_exception *fnhe;
1407
1408 fnhe = find_exception(nhc, daddr);
1409 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1410 mtu = fnhe->fnhe_pmtu;
1411 }
1412
1413 if (likely(!mtu))
1414 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1415
1416 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1417 }
1418
1419 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1420 __be32 daddr, const bool do_cache)
1421 {
1422 bool ret = false;
1423
1424 spin_lock_bh(&fnhe_lock);
1425
1426 if (daddr == fnhe->fnhe_daddr) {
1427 struct rtable __rcu **porig;
1428 struct rtable *orig;
1429 int genid = fnhe_genid(dev_net(rt->dst.dev));
1430
1431 if (rt_is_input_route(rt))
1432 porig = &fnhe->fnhe_rth_input;
1433 else
1434 porig = &fnhe->fnhe_rth_output;
1435 orig = rcu_dereference(*porig);
1436
1437 if (fnhe->fnhe_genid != genid) {
1438 fnhe->fnhe_genid = genid;
1439 fnhe->fnhe_gw = 0;
1440 fnhe->fnhe_pmtu = 0;
1441 fnhe->fnhe_expires = 0;
1442 fnhe->fnhe_mtu_locked = false;
1443 fnhe_flush_routes(fnhe);
1444 orig = NULL;
1445 }
1446 fill_route_from_fnhe(rt, fnhe);
1447 if (!rt->rt_gw4) {
1448 rt->rt_gw4 = daddr;
1449 rt->rt_gw_family = AF_INET;
1450 }
1451
1452 if (do_cache) {
1453 dst_hold(&rt->dst);
1454 rcu_assign_pointer(*porig, rt);
1455 if (orig) {
1456 dst_dev_put(&orig->dst);
1457 dst_release(&orig->dst);
1458 }
1459 ret = true;
1460 }
1461
1462 fnhe->fnhe_stamp = jiffies;
1463 }
1464 spin_unlock_bh(&fnhe_lock);
1465
1466 return ret;
1467 }
1468
1469 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1470 {
1471 struct rtable *orig, *prev, **p;
1472 bool ret = true;
1473
1474 if (rt_is_input_route(rt)) {
1475 p = (struct rtable **)&nhc->nhc_rth_input;
1476 } else {
1477 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1478 }
1479 orig = *p;
1480
1481 /* hold dst before doing cmpxchg() to avoid race condition
1482 * on this dst
1483 */
1484 dst_hold(&rt->dst);
1485 prev = cmpxchg(p, orig, rt);
1486 if (prev == orig) {
1487 if (orig) {
1488 rt_add_uncached_list(orig);
1489 dst_release(&orig->dst);
1490 }
1491 } else {
1492 dst_release(&rt->dst);
1493 ret = false;
1494 }
1495
1496 return ret;
1497 }
1498
1499 struct uncached_list {
1500 spinlock_t lock;
1501 struct list_head head;
1502 };
1503
1504 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1505
1506 void rt_add_uncached_list(struct rtable *rt)
1507 {
1508 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1509
1510 rt->rt_uncached_list = ul;
1511
1512 spin_lock_bh(&ul->lock);
1513 list_add_tail(&rt->rt_uncached, &ul->head);
1514 spin_unlock_bh(&ul->lock);
1515 }
1516
1517 void rt_del_uncached_list(struct rtable *rt)
1518 {
1519 if (!list_empty(&rt->rt_uncached)) {
1520 struct uncached_list *ul = rt->rt_uncached_list;
1521
1522 spin_lock_bh(&ul->lock);
1523 list_del(&rt->rt_uncached);
1524 spin_unlock_bh(&ul->lock);
1525 }
1526 }
1527
1528 static void ipv4_dst_destroy(struct dst_entry *dst)
1529 {
1530 struct rtable *rt = (struct rtable *)dst;
1531
1532 ip_dst_metrics_put(dst);
1533 rt_del_uncached_list(rt);
1534 }
1535
1536 void rt_flush_dev(struct net_device *dev)
1537 {
1538 struct rtable *rt;
1539 int cpu;
1540
1541 for_each_possible_cpu(cpu) {
1542 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1543
1544 spin_lock_bh(&ul->lock);
1545 list_for_each_entry(rt, &ul->head, rt_uncached) {
1546 if (rt->dst.dev != dev)
1547 continue;
1548 rt->dst.dev = blackhole_netdev;
1549 dev_hold(rt->dst.dev);
1550 dev_put(dev);
1551 }
1552 spin_unlock_bh(&ul->lock);
1553 }
1554 }
1555
1556 static bool rt_cache_valid(const struct rtable *rt)
1557 {
1558 return rt &&
1559 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1560 !rt_is_expired(rt);
1561 }
1562
1563 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1564 const struct fib_result *res,
1565 struct fib_nh_exception *fnhe,
1566 struct fib_info *fi, u16 type, u32 itag,
1567 const bool do_cache)
1568 {
1569 bool cached = false;
1570
1571 if (fi) {
1572 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1573
1574 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1575 rt->rt_uses_gateway = 1;
1576 rt->rt_gw_family = nhc->nhc_gw_family;
1577 /* only INET and INET6 are supported */
1578 if (likely(nhc->nhc_gw_family == AF_INET))
1579 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1580 else
1581 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1582 }
1583
1584 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1585
1586 #ifdef CONFIG_IP_ROUTE_CLASSID
1587 if (nhc->nhc_family == AF_INET) {
1588 struct fib_nh *nh;
1589
1590 nh = container_of(nhc, struct fib_nh, nh_common);
1591 rt->dst.tclassid = nh->nh_tclassid;
1592 }
1593 #endif
1594 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1595 if (unlikely(fnhe))
1596 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1597 else if (do_cache)
1598 cached = rt_cache_route(nhc, rt);
1599 if (unlikely(!cached)) {
1600 /* Routes we intend to cache in nexthop exception or
1601 * FIB nexthop have the DST_NOCACHE bit clear.
1602 * However, if we are unsuccessful at storing this
1603 * route into the cache we really need to set it.
1604 */
1605 if (!rt->rt_gw4) {
1606 rt->rt_gw_family = AF_INET;
1607 rt->rt_gw4 = daddr;
1608 }
1609 rt_add_uncached_list(rt);
1610 }
1611 } else
1612 rt_add_uncached_list(rt);
1613
1614 #ifdef CONFIG_IP_ROUTE_CLASSID
1615 #ifdef CONFIG_IP_MULTIPLE_TABLES
1616 set_class_tag(rt, res->tclassid);
1617 #endif
1618 set_class_tag(rt, itag);
1619 #endif
1620 }
1621
1622 struct rtable *rt_dst_alloc(struct net_device *dev,
1623 unsigned int flags, u16 type,
1624 bool nopolicy, bool noxfrm, bool will_cache)
1625 {
1626 struct rtable *rt;
1627
1628 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1629 (will_cache ? 0 : DST_HOST) |
1630 (nopolicy ? DST_NOPOLICY : 0) |
1631 (noxfrm ? DST_NOXFRM : 0));
1632
1633 if (rt) {
1634 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1635 rt->rt_flags = flags;
1636 rt->rt_type = type;
1637 rt->rt_is_input = 0;
1638 rt->rt_iif = 0;
1639 rt->rt_pmtu = 0;
1640 rt->rt_mtu_locked = 0;
1641 rt->rt_uses_gateway = 0;
1642 rt->rt_gw_family = 0;
1643 rt->rt_gw4 = 0;
1644 INIT_LIST_HEAD(&rt->rt_uncached);
1645
1646 rt->dst.output = ip_output;
1647 if (flags & RTCF_LOCAL)
1648 rt->dst.input = ip_local_deliver;
1649 }
1650
1651 return rt;
1652 }
1653 EXPORT_SYMBOL(rt_dst_alloc);
1654
1655 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1656 {
1657 struct rtable *new_rt;
1658
1659 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1660 rt->dst.flags);
1661
1662 if (new_rt) {
1663 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1664 new_rt->rt_flags = rt->rt_flags;
1665 new_rt->rt_type = rt->rt_type;
1666 new_rt->rt_is_input = rt->rt_is_input;
1667 new_rt->rt_iif = rt->rt_iif;
1668 new_rt->rt_pmtu = rt->rt_pmtu;
1669 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1670 new_rt->rt_gw_family = rt->rt_gw_family;
1671 if (rt->rt_gw_family == AF_INET)
1672 new_rt->rt_gw4 = rt->rt_gw4;
1673 else if (rt->rt_gw_family == AF_INET6)
1674 new_rt->rt_gw6 = rt->rt_gw6;
1675 INIT_LIST_HEAD(&new_rt->rt_uncached);
1676
1677 new_rt->dst.flags |= DST_HOST;
1678 new_rt->dst.input = rt->dst.input;
1679 new_rt->dst.output = rt->dst.output;
1680 new_rt->dst.error = rt->dst.error;
1681 new_rt->dst.lastuse = jiffies;
1682 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1683 }
1684 return new_rt;
1685 }
1686 EXPORT_SYMBOL(rt_dst_clone);
1687
1688 /* called in rcu_read_lock() section */
1689 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1690 u8 tos, struct net_device *dev,
1691 struct in_device *in_dev, u32 *itag)
1692 {
1693 int err;
1694
1695 /* Primary sanity checks. */
1696 if (!in_dev)
1697 return -EINVAL;
1698
1699 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1700 skb->protocol != htons(ETH_P_IP))
1701 return -EINVAL;
1702
1703 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1704 return -EINVAL;
1705
1706 if (ipv4_is_zeronet(saddr)) {
1707 if (!ipv4_is_local_multicast(daddr) &&
1708 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1709 return -EINVAL;
1710 } else {
1711 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1712 in_dev, itag);
1713 if (err < 0)
1714 return err;
1715 }
1716 return 0;
1717 }
1718
1719 /* called in rcu_read_lock() section */
1720 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1721 u8 tos, struct net_device *dev, int our)
1722 {
1723 struct in_device *in_dev = __in_dev_get_rcu(dev);
1724 unsigned int flags = RTCF_MULTICAST;
1725 struct rtable *rth;
1726 u32 itag = 0;
1727 int err;
1728
1729 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1730 if (err)
1731 return err;
1732
1733 if (our)
1734 flags |= RTCF_LOCAL;
1735
1736 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1737 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false);
1738 if (!rth)
1739 return -ENOBUFS;
1740
1741 #ifdef CONFIG_IP_ROUTE_CLASSID
1742 rth->dst.tclassid = itag;
1743 #endif
1744 rth->dst.output = ip_rt_bug;
1745 rth->rt_is_input= 1;
1746
1747 #ifdef CONFIG_IP_MROUTE
1748 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1749 rth->dst.input = ip_mr_input;
1750 #endif
1751 RT_CACHE_STAT_INC(in_slow_mc);
1752
1753 skb_dst_set(skb, &rth->dst);
1754 return 0;
1755 }
1756
1757
1758 static void ip_handle_martian_source(struct net_device *dev,
1759 struct in_device *in_dev,
1760 struct sk_buff *skb,
1761 __be32 daddr,
1762 __be32 saddr)
1763 {
1764 RT_CACHE_STAT_INC(in_martian_src);
1765 #ifdef CONFIG_IP_ROUTE_VERBOSE
1766 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1767 /*
1768 * RFC1812 recommendation, if source is martian,
1769 * the only hint is MAC header.
1770 */
1771 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1772 &daddr, &saddr, dev->name);
1773 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1774 print_hex_dump(KERN_WARNING, "ll header: ",
1775 DUMP_PREFIX_OFFSET, 16, 1,
1776 skb_mac_header(skb),
1777 dev->hard_header_len, false);
1778 }
1779 }
1780 #endif
1781 }
1782
1783 /* called in rcu_read_lock() section */
1784 static int __mkroute_input(struct sk_buff *skb,
1785 const struct fib_result *res,
1786 struct in_device *in_dev,
1787 __be32 daddr, __be32 saddr, u32 tos)
1788 {
1789 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1790 struct net_device *dev = nhc->nhc_dev;
1791 struct fib_nh_exception *fnhe;
1792 struct rtable *rth;
1793 int err;
1794 struct in_device *out_dev;
1795 bool do_cache;
1796 u32 itag = 0;
1797
1798 /* get a working reference to the output device */
1799 out_dev = __in_dev_get_rcu(dev);
1800 if (!out_dev) {
1801 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1802 return -EINVAL;
1803 }
1804
1805 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1806 in_dev->dev, in_dev, &itag);
1807 if (err < 0) {
1808 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1809 saddr);
1810
1811 goto cleanup;
1812 }
1813
1814 do_cache = res->fi && !itag;
1815 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1816 skb->protocol == htons(ETH_P_IP)) {
1817 __be32 gw;
1818
1819 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1820 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1821 inet_addr_onlink(out_dev, saddr, gw))
1822 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1823 }
1824
1825 if (skb->protocol != htons(ETH_P_IP)) {
1826 /* Not IP (i.e. ARP). Do not create route, if it is
1827 * invalid for proxy arp. DNAT routes are always valid.
1828 *
1829 * Proxy arp feature have been extended to allow, ARP
1830 * replies back to the same interface, to support
1831 * Private VLAN switch technologies. See arp.c.
1832 */
1833 if (out_dev == in_dev &&
1834 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1835 err = -EINVAL;
1836 goto cleanup;
1837 }
1838 }
1839
1840 fnhe = find_exception(nhc, daddr);
1841 if (do_cache) {
1842 if (fnhe)
1843 rth = rcu_dereference(fnhe->fnhe_rth_input);
1844 else
1845 rth = rcu_dereference(nhc->nhc_rth_input);
1846 if (rt_cache_valid(rth)) {
1847 skb_dst_set_noref(skb, &rth->dst);
1848 goto out;
1849 }
1850 }
1851
1852 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1853 IN_DEV_CONF_GET(in_dev, NOPOLICY),
1854 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache);
1855 if (!rth) {
1856 err = -ENOBUFS;
1857 goto cleanup;
1858 }
1859
1860 rth->rt_is_input = 1;
1861 RT_CACHE_STAT_INC(in_slow_tot);
1862
1863 rth->dst.input = ip_forward;
1864
1865 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1866 do_cache);
1867 lwtunnel_set_redirect(&rth->dst);
1868 skb_dst_set(skb, &rth->dst);
1869 out:
1870 err = 0;
1871 cleanup:
1872 return err;
1873 }
1874
1875 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1876 /* To make ICMP packets follow the right flow, the multipath hash is
1877 * calculated from the inner IP addresses.
1878 */
1879 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1880 struct flow_keys *hash_keys)
1881 {
1882 const struct iphdr *outer_iph = ip_hdr(skb);
1883 const struct iphdr *key_iph = outer_iph;
1884 const struct iphdr *inner_iph;
1885 const struct icmphdr *icmph;
1886 struct iphdr _inner_iph;
1887 struct icmphdr _icmph;
1888
1889 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1890 goto out;
1891
1892 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1893 goto out;
1894
1895 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1896 &_icmph);
1897 if (!icmph)
1898 goto out;
1899
1900 if (!icmp_is_err(icmph->type))
1901 goto out;
1902
1903 inner_iph = skb_header_pointer(skb,
1904 outer_iph->ihl * 4 + sizeof(_icmph),
1905 sizeof(_inner_iph), &_inner_iph);
1906 if (!inner_iph)
1907 goto out;
1908
1909 key_iph = inner_iph;
1910 out:
1911 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1912 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1913 }
1914
1915 /* if skb is set it will be used and fl4 can be NULL */
1916 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
1917 const struct sk_buff *skb, struct flow_keys *flkeys)
1918 {
1919 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
1920 struct flow_keys hash_keys;
1921 u32 mhash;
1922
1923 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
1924 case 0:
1925 memset(&hash_keys, 0, sizeof(hash_keys));
1926 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1927 if (skb) {
1928 ip_multipath_l3_keys(skb, &hash_keys);
1929 } else {
1930 hash_keys.addrs.v4addrs.src = fl4->saddr;
1931 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1932 }
1933 break;
1934 case 1:
1935 /* skb is currently provided only when forwarding */
1936 if (skb) {
1937 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
1938 struct flow_keys keys;
1939
1940 /* short-circuit if we already have L4 hash present */
1941 if (skb->l4_hash)
1942 return skb_get_hash_raw(skb) >> 1;
1943
1944 memset(&hash_keys, 0, sizeof(hash_keys));
1945
1946 if (!flkeys) {
1947 skb_flow_dissect_flow_keys(skb, &keys, flag);
1948 flkeys = &keys;
1949 }
1950
1951 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1952 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
1953 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
1954 hash_keys.ports.src = flkeys->ports.src;
1955 hash_keys.ports.dst = flkeys->ports.dst;
1956 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
1957 } else {
1958 memset(&hash_keys, 0, sizeof(hash_keys));
1959 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1960 hash_keys.addrs.v4addrs.src = fl4->saddr;
1961 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1962 hash_keys.ports.src = fl4->fl4_sport;
1963 hash_keys.ports.dst = fl4->fl4_dport;
1964 hash_keys.basic.ip_proto = fl4->flowi4_proto;
1965 }
1966 break;
1967 case 2:
1968 memset(&hash_keys, 0, sizeof(hash_keys));
1969 /* skb is currently provided only when forwarding */
1970 if (skb) {
1971 struct flow_keys keys;
1972
1973 skb_flow_dissect_flow_keys(skb, &keys, 0);
1974 /* Inner can be v4 or v6 */
1975 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1976 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1977 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1978 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1979 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1980 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1981 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1982 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1983 hash_keys.tags.flow_label = keys.tags.flow_label;
1984 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1985 } else {
1986 /* Same as case 0 */
1987 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1988 ip_multipath_l3_keys(skb, &hash_keys);
1989 }
1990 } else {
1991 /* Same as case 0 */
1992 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1993 hash_keys.addrs.v4addrs.src = fl4->saddr;
1994 hash_keys.addrs.v4addrs.dst = fl4->daddr;
1995 }
1996 break;
1997 }
1998 mhash = flow_hash_from_keys(&hash_keys);
1999
2000 if (multipath_hash)
2001 mhash = jhash_2words(mhash, multipath_hash, 0);
2002
2003 return mhash >> 1;
2004 }
2005 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
2006
2007 static int ip_mkroute_input(struct sk_buff *skb,
2008 struct fib_result *res,
2009 struct in_device *in_dev,
2010 __be32 daddr, __be32 saddr, u32 tos,
2011 struct flow_keys *hkeys)
2012 {
2013 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2014 if (res->fi && fib_info_num_path(res->fi) > 1) {
2015 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2016
2017 fib_select_multipath(res, h);
2018 }
2019 #endif
2020
2021 /* create a routing cache entry */
2022 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2023 }
2024
2025 /* Implements all the saddr-related checks as ip_route_input_slow(),
2026 * assuming daddr is valid and the destination is not a local broadcast one.
2027 * Uses the provided hint instead of performing a route lookup.
2028 */
2029 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2030 u8 tos, struct net_device *dev,
2031 const struct sk_buff *hint)
2032 {
2033 struct in_device *in_dev = __in_dev_get_rcu(dev);
2034 struct rtable *rt = (struct rtable *)hint;
2035 struct net *net = dev_net(dev);
2036 int err = -EINVAL;
2037 u32 tag = 0;
2038
2039 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2040 goto martian_source;
2041
2042 if (ipv4_is_zeronet(saddr))
2043 goto martian_source;
2044
2045 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2046 goto martian_source;
2047
2048 if (rt->rt_type != RTN_LOCAL)
2049 goto skip_validate_source;
2050
2051 tos &= IPTOS_RT_MASK;
2052 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2053 if (err < 0)
2054 goto martian_source;
2055
2056 skip_validate_source:
2057 skb_dst_copy(skb, hint);
2058 return 0;
2059
2060 martian_source:
2061 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2062 return err;
2063 }
2064
2065 /*
2066 * NOTE. We drop all the packets that has local source
2067 * addresses, because every properly looped back packet
2068 * must have correct destination already attached by output routine.
2069 * Changes in the enforced policies must be applied also to
2070 * ip_route_use_hint().
2071 *
2072 * Such approach solves two big problems:
2073 * 1. Not simplex devices are handled properly.
2074 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2075 * called with rcu_read_lock()
2076 */
2077
2078 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2079 u8 tos, struct net_device *dev,
2080 struct fib_result *res)
2081 {
2082 struct in_device *in_dev = __in_dev_get_rcu(dev);
2083 struct flow_keys *flkeys = NULL, _flkeys;
2084 struct net *net = dev_net(dev);
2085 struct ip_tunnel_info *tun_info;
2086 int err = -EINVAL;
2087 unsigned int flags = 0;
2088 u32 itag = 0;
2089 struct rtable *rth;
2090 struct flowi4 fl4;
2091 bool do_cache = true;
2092
2093 /* IP on this device is disabled. */
2094
2095 if (!in_dev)
2096 goto out;
2097
2098 /* Check for the most weird martians, which can be not detected
2099 by fib_lookup.
2100 */
2101
2102 tun_info = skb_tunnel_info(skb);
2103 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2104 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2105 else
2106 fl4.flowi4_tun_key.tun_id = 0;
2107 skb_dst_drop(skb);
2108
2109 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2110 goto martian_source;
2111
2112 res->fi = NULL;
2113 res->table = NULL;
2114 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2115 goto brd_input;
2116
2117 /* Accept zero addresses only to limited broadcast;
2118 * I even do not know to fix it or not. Waiting for complains :-)
2119 */
2120 if (ipv4_is_zeronet(saddr))
2121 goto martian_source;
2122
2123 if (ipv4_is_zeronet(daddr))
2124 goto martian_destination;
2125
2126 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2127 * and call it once if daddr or/and saddr are loopback addresses
2128 */
2129 if (ipv4_is_loopback(daddr)) {
2130 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2131 goto martian_destination;
2132 } else if (ipv4_is_loopback(saddr)) {
2133 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2134 goto martian_source;
2135 }
2136
2137 /*
2138 * Now we are ready to route packet.
2139 */
2140 fl4.flowi4_oif = 0;
2141 fl4.flowi4_iif = dev->ifindex;
2142 fl4.flowi4_mark = skb->mark;
2143 fl4.flowi4_tos = tos;
2144 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2145 fl4.flowi4_flags = 0;
2146 fl4.daddr = daddr;
2147 fl4.saddr = saddr;
2148 fl4.flowi4_uid = sock_net_uid(net, NULL);
2149
2150 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2151 flkeys = &_flkeys;
2152 } else {
2153 fl4.flowi4_proto = 0;
2154 fl4.fl4_sport = 0;
2155 fl4.fl4_dport = 0;
2156 }
2157
2158 err = fib_lookup(net, &fl4, res, 0);
2159 if (err != 0) {
2160 if (!IN_DEV_FORWARD(in_dev))
2161 err = -EHOSTUNREACH;
2162 goto no_route;
2163 }
2164
2165 if (res->type == RTN_BROADCAST) {
2166 if (IN_DEV_BFORWARD(in_dev))
2167 goto make_route;
2168 /* not do cache if bc_forwarding is enabled */
2169 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))
2170 do_cache = false;
2171 goto brd_input;
2172 }
2173
2174 if (res->type == RTN_LOCAL) {
2175 err = fib_validate_source(skb, saddr, daddr, tos,
2176 0, dev, in_dev, &itag);
2177 if (err < 0)
2178 goto martian_source;
2179 goto local_input;
2180 }
2181
2182 if (!IN_DEV_FORWARD(in_dev)) {
2183 err = -EHOSTUNREACH;
2184 goto no_route;
2185 }
2186 if (res->type != RTN_UNICAST)
2187 goto martian_destination;
2188
2189 make_route:
2190 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2191 out: return err;
2192
2193 brd_input:
2194 if (skb->protocol != htons(ETH_P_IP))
2195 goto e_inval;
2196
2197 if (!ipv4_is_zeronet(saddr)) {
2198 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2199 in_dev, &itag);
2200 if (err < 0)
2201 goto martian_source;
2202 }
2203 flags |= RTCF_BROADCAST;
2204 res->type = RTN_BROADCAST;
2205 RT_CACHE_STAT_INC(in_brd);
2206
2207 local_input:
2208 do_cache &= res->fi && !itag;
2209 if (do_cache) {
2210 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2211
2212 rth = rcu_dereference(nhc->nhc_rth_input);
2213 if (rt_cache_valid(rth)) {
2214 skb_dst_set_noref(skb, &rth->dst);
2215 err = 0;
2216 goto out;
2217 }
2218 }
2219
2220 rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,
2221 flags | RTCF_LOCAL, res->type,
2222 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);
2223 if (!rth)
2224 goto e_nobufs;
2225
2226 rth->dst.output= ip_rt_bug;
2227 #ifdef CONFIG_IP_ROUTE_CLASSID
2228 rth->dst.tclassid = itag;
2229 #endif
2230 rth->rt_is_input = 1;
2231
2232 RT_CACHE_STAT_INC(in_slow_tot);
2233 if (res->type == RTN_UNREACHABLE) {
2234 rth->dst.input= ip_error;
2235 rth->dst.error= -err;
2236 rth->rt_flags &= ~RTCF_LOCAL;
2237 }
2238
2239 if (do_cache) {
2240 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2241
2242 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2243 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2244 WARN_ON(rth->dst.input == lwtunnel_input);
2245 rth->dst.lwtstate->orig_input = rth->dst.input;
2246 rth->dst.input = lwtunnel_input;
2247 }
2248
2249 if (unlikely(!rt_cache_route(nhc, rth)))
2250 rt_add_uncached_list(rth);
2251 }
2252 skb_dst_set(skb, &rth->dst);
2253 err = 0;
2254 goto out;
2255
2256 no_route:
2257 RT_CACHE_STAT_INC(in_no_route);
2258 res->type = RTN_UNREACHABLE;
2259 res->fi = NULL;
2260 res->table = NULL;
2261 goto local_input;
2262
2263 /*
2264 * Do not cache martian addresses: they should be logged (RFC1812)
2265 */
2266 martian_destination:
2267 RT_CACHE_STAT_INC(in_martian_dst);
2268 #ifdef CONFIG_IP_ROUTE_VERBOSE
2269 if (IN_DEV_LOG_MARTIANS(in_dev))
2270 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2271 &daddr, &saddr, dev->name);
2272 #endif
2273
2274 e_inval:
2275 err = -EINVAL;
2276 goto out;
2277
2278 e_nobufs:
2279 err = -ENOBUFS;
2280 goto out;
2281
2282 martian_source:
2283 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2284 goto out;
2285 }
2286
2287 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2288 u8 tos, struct net_device *dev)
2289 {
2290 struct fib_result res;
2291 int err;
2292
2293 tos &= IPTOS_RT_MASK;
2294 rcu_read_lock();
2295 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2296 rcu_read_unlock();
2297
2298 return err;
2299 }
2300 EXPORT_SYMBOL(ip_route_input_noref);
2301
2302 /* called with rcu_read_lock held */
2303 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2304 u8 tos, struct net_device *dev, struct fib_result *res)
2305 {
2306 /* Multicast recognition logic is moved from route cache to here.
2307 The problem was that too many Ethernet cards have broken/missing
2308 hardware multicast filters :-( As result the host on multicasting
2309 network acquires a lot of useless route cache entries, sort of
2310 SDR messages from all the world. Now we try to get rid of them.
2311 Really, provided software IP multicast filter is organized
2312 reasonably (at least, hashed), it does not result in a slowdown
2313 comparing with route cache reject entries.
2314 Note, that multicast routers are not affected, because
2315 route cache entry is created eventually.
2316 */
2317 if (ipv4_is_multicast(daddr)) {
2318 struct in_device *in_dev = __in_dev_get_rcu(dev);
2319 int our = 0;
2320 int err = -EINVAL;
2321
2322 if (!in_dev)
2323 return err;
2324 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2325 ip_hdr(skb)->protocol);
2326
2327 /* check l3 master if no match yet */
2328 if (!our && netif_is_l3_slave(dev)) {
2329 struct in_device *l3_in_dev;
2330
2331 l3_in_dev = __in_dev_get_rcu(skb->dev);
2332 if (l3_in_dev)
2333 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2334 ip_hdr(skb)->protocol);
2335 }
2336
2337 if (our
2338 #ifdef CONFIG_IP_MROUTE
2339 ||
2340 (!ipv4_is_local_multicast(daddr) &&
2341 IN_DEV_MFORWARD(in_dev))
2342 #endif
2343 ) {
2344 err = ip_route_input_mc(skb, daddr, saddr,
2345 tos, dev, our);
2346 }
2347 return err;
2348 }
2349
2350 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2351 }
2352
2353 /* called with rcu_read_lock() */
2354 static struct rtable *__mkroute_output(const struct fib_result *res,
2355 const struct flowi4 *fl4, int orig_oif,
2356 struct net_device *dev_out,
2357 unsigned int flags)
2358 {
2359 struct fib_info *fi = res->fi;
2360 struct fib_nh_exception *fnhe;
2361 struct in_device *in_dev;
2362 u16 type = res->type;
2363 struct rtable *rth;
2364 bool do_cache;
2365
2366 in_dev = __in_dev_get_rcu(dev_out);
2367 if (!in_dev)
2368 return ERR_PTR(-EINVAL);
2369
2370 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2371 if (ipv4_is_loopback(fl4->saddr) &&
2372 !(dev_out->flags & IFF_LOOPBACK) &&
2373 !netif_is_l3_master(dev_out))
2374 return ERR_PTR(-EINVAL);
2375
2376 if (ipv4_is_lbcast(fl4->daddr))
2377 type = RTN_BROADCAST;
2378 else if (ipv4_is_multicast(fl4->daddr))
2379 type = RTN_MULTICAST;
2380 else if (ipv4_is_zeronet(fl4->daddr))
2381 return ERR_PTR(-EINVAL);
2382
2383 if (dev_out->flags & IFF_LOOPBACK)
2384 flags |= RTCF_LOCAL;
2385
2386 do_cache = true;
2387 if (type == RTN_BROADCAST) {
2388 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2389 fi = NULL;
2390 } else if (type == RTN_MULTICAST) {
2391 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2392 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2393 fl4->flowi4_proto))
2394 flags &= ~RTCF_LOCAL;
2395 else
2396 do_cache = false;
2397 /* If multicast route do not exist use
2398 * default one, but do not gateway in this case.
2399 * Yes, it is hack.
2400 */
2401 if (fi && res->prefixlen < 4)
2402 fi = NULL;
2403 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2404 (orig_oif != dev_out->ifindex)) {
2405 /* For local routes that require a particular output interface
2406 * we do not want to cache the result. Caching the result
2407 * causes incorrect behaviour when there are multiple source
2408 * addresses on the interface, the end result being that if the
2409 * intended recipient is waiting on that interface for the
2410 * packet he won't receive it because it will be delivered on
2411 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2412 * be set to the loopback interface as well.
2413 */
2414 do_cache = false;
2415 }
2416
2417 fnhe = NULL;
2418 do_cache &= fi != NULL;
2419 if (fi) {
2420 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2421 struct rtable __rcu **prth;
2422
2423 fnhe = find_exception(nhc, fl4->daddr);
2424 if (!do_cache)
2425 goto add;
2426 if (fnhe) {
2427 prth = &fnhe->fnhe_rth_output;
2428 } else {
2429 if (unlikely(fl4->flowi4_flags &
2430 FLOWI_FLAG_KNOWN_NH &&
2431 !(nhc->nhc_gw_family &&
2432 nhc->nhc_scope == RT_SCOPE_LINK))) {
2433 do_cache = false;
2434 goto add;
2435 }
2436 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2437 }
2438 rth = rcu_dereference(*prth);
2439 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2440 return rth;
2441 }
2442
2443 add:
2444 rth = rt_dst_alloc(dev_out, flags, type,
2445 IN_DEV_CONF_GET(in_dev, NOPOLICY),
2446 IN_DEV_CONF_GET(in_dev, NOXFRM),
2447 do_cache);
2448 if (!rth)
2449 return ERR_PTR(-ENOBUFS);
2450
2451 rth->rt_iif = orig_oif;
2452
2453 RT_CACHE_STAT_INC(out_slow_tot);
2454
2455 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2456 if (flags & RTCF_LOCAL &&
2457 !(dev_out->flags & IFF_LOOPBACK)) {
2458 rth->dst.output = ip_mc_output;
2459 RT_CACHE_STAT_INC(out_slow_mc);
2460 }
2461 #ifdef CONFIG_IP_MROUTE
2462 if (type == RTN_MULTICAST) {
2463 if (IN_DEV_MFORWARD(in_dev) &&
2464 !ipv4_is_local_multicast(fl4->daddr)) {
2465 rth->dst.input = ip_mr_input;
2466 rth->dst.output = ip_mc_output;
2467 }
2468 }
2469 #endif
2470 }
2471
2472 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2473 lwtunnel_set_redirect(&rth->dst);
2474
2475 return rth;
2476 }
2477
2478 /*
2479 * Major route resolver routine.
2480 */
2481
2482 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2483 const struct sk_buff *skb)
2484 {
2485 __u8 tos = RT_FL_TOS(fl4);
2486 struct fib_result res = {
2487 .type = RTN_UNSPEC,
2488 .fi = NULL,
2489 .table = NULL,
2490 .tclassid = 0,
2491 };
2492 struct rtable *rth;
2493
2494 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2495 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
2496 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2497 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2498
2499 rcu_read_lock();
2500 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2501 rcu_read_unlock();
2502
2503 return rth;
2504 }
2505 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2506
2507 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2508 struct fib_result *res,
2509 const struct sk_buff *skb)
2510 {
2511 struct net_device *dev_out = NULL;
2512 int orig_oif = fl4->flowi4_oif;
2513 unsigned int flags = 0;
2514 struct rtable *rth;
2515 int err;
2516
2517 if (fl4->saddr) {
2518 if (ipv4_is_multicast(fl4->saddr) ||
2519 ipv4_is_lbcast(fl4->saddr) ||
2520 ipv4_is_zeronet(fl4->saddr)) {
2521 rth = ERR_PTR(-EINVAL);
2522 goto out;
2523 }
2524
2525 rth = ERR_PTR(-ENETUNREACH);
2526
2527 /* I removed check for oif == dev_out->oif here.
2528 It was wrong for two reasons:
2529 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2530 is assigned to multiple interfaces.
2531 2. Moreover, we are allowed to send packets with saddr
2532 of another iface. --ANK
2533 */
2534
2535 if (fl4->flowi4_oif == 0 &&
2536 (ipv4_is_multicast(fl4->daddr) ||
2537 ipv4_is_lbcast(fl4->daddr))) {
2538 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2539 dev_out = __ip_dev_find(net, fl4->saddr, false);
2540 if (!dev_out)
2541 goto out;
2542
2543 /* Special hack: user can direct multicasts
2544 and limited broadcast via necessary interface
2545 without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2546 This hack is not just for fun, it allows
2547 vic,vat and friends to work.
2548 They bind socket to loopback, set ttl to zero
2549 and expect that it will work.
2550 From the viewpoint of routing cache they are broken,
2551 because we are not allowed to build multicast path
2552 with loopback source addr (look, routing cache
2553 cannot know, that ttl is zero, so that packet
2554 will not leave this host and route is valid).
2555 Luckily, this hack is good workaround.
2556 */
2557
2558 fl4->flowi4_oif = dev_out->ifindex;
2559 goto make_route;
2560 }
2561
2562 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2563 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2564 if (!__ip_dev_find(net, fl4->saddr, false))
2565 goto out;
2566 }
2567 }
2568
2569
2570 if (fl4->flowi4_oif) {
2571 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2572 rth = ERR_PTR(-ENODEV);
2573 if (!dev_out)
2574 goto out;
2575
2576 /* RACE: Check return value of inet_select_addr instead. */
2577 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2578 rth = ERR_PTR(-ENETUNREACH);
2579 goto out;
2580 }
2581 if (ipv4_is_local_multicast(fl4->daddr) ||
2582 ipv4_is_lbcast(fl4->daddr) ||
2583 fl4->flowi4_proto == IPPROTO_IGMP) {
2584 if (!fl4->saddr)
2585 fl4->saddr = inet_select_addr(dev_out, 0,
2586 RT_SCOPE_LINK);
2587 goto make_route;
2588 }
2589 if (!fl4->saddr) {
2590 if (ipv4_is_multicast(fl4->daddr))
2591 fl4->saddr = inet_select_addr(dev_out, 0,
2592 fl4->flowi4_scope);
2593 else if (!fl4->daddr)
2594 fl4->saddr = inet_select_addr(dev_out, 0,
2595 RT_SCOPE_HOST);
2596 }
2597 }
2598
2599 if (!fl4->daddr) {
2600 fl4->daddr = fl4->saddr;
2601 if (!fl4->daddr)
2602 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2603 dev_out = net->loopback_dev;
2604 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2605 res->type = RTN_LOCAL;
2606 flags |= RTCF_LOCAL;
2607 goto make_route;
2608 }
2609
2610 err = fib_lookup(net, fl4, res, 0);
2611 if (err) {
2612 res->fi = NULL;
2613 res->table = NULL;
2614 if (fl4->flowi4_oif &&
2615 (ipv4_is_multicast(fl4->daddr) ||
2616 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2617 /* Apparently, routing tables are wrong. Assume,
2618 that the destination is on link.
2619
2620 WHY? DW.
2621 Because we are allowed to send to iface
2622 even if it has NO routes and NO assigned
2623 addresses. When oif is specified, routing
2624 tables are looked up with only one purpose:
2625 to catch if destination is gatewayed, rather than
2626 direct. Moreover, if MSG_DONTROUTE is set,
2627 we send packet, ignoring both routing tables
2628 and ifaddr state. --ANK
2629
2630
2631 We could make it even if oif is unknown,
2632 likely IPv6, but we do not.
2633 */
2634
2635 if (fl4->saddr == 0)
2636 fl4->saddr = inet_select_addr(dev_out, 0,
2637 RT_SCOPE_LINK);
2638 res->type = RTN_UNICAST;
2639 goto make_route;
2640 }
2641 rth = ERR_PTR(err);
2642 goto out;
2643 }
2644
2645 if (res->type == RTN_LOCAL) {
2646 if (!fl4->saddr) {
2647 if (res->fi->fib_prefsrc)
2648 fl4->saddr = res->fi->fib_prefsrc;
2649 else
2650 fl4->saddr = fl4->daddr;
2651 }
2652
2653 /* L3 master device is the loopback for that domain */
2654 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2655 net->loopback_dev;
2656
2657 /* make sure orig_oif points to fib result device even
2658 * though packet rx/tx happens over loopback or l3mdev
2659 */
2660 orig_oif = FIB_RES_OIF(*res);
2661
2662 fl4->flowi4_oif = dev_out->ifindex;
2663 flags |= RTCF_LOCAL;
2664 goto make_route;
2665 }
2666
2667 fib_select_path(net, res, fl4, skb);
2668
2669 dev_out = FIB_RES_DEV(*res);
2670 fl4->flowi4_oif = dev_out->ifindex;
2671
2672
2673 make_route:
2674 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2675
2676 out:
2677 return rth;
2678 }
2679
2680 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
2681 {
2682 return NULL;
2683 }
2684
2685 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
2686 {
2687 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
2688
2689 return mtu ? : dst->dev->mtu;
2690 }
2691
2692 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
2693 struct sk_buff *skb, u32 mtu,
2694 bool confirm_neigh)
2695 {
2696 }
2697
2698 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
2699 struct sk_buff *skb)
2700 {
2701 }
2702
2703 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
2704 unsigned long old)
2705 {
2706 return NULL;
2707 }
2708
2709 static struct dst_ops ipv4_dst_blackhole_ops = {
2710 .family = AF_INET,
2711 .check = ipv4_blackhole_dst_check,
2712 .mtu = ipv4_blackhole_mtu,
2713 .default_advmss = ipv4_default_advmss,
2714 .update_pmtu = ipv4_rt_blackhole_update_pmtu,
2715 .redirect = ipv4_rt_blackhole_redirect,
2716 .cow_metrics = ipv4_rt_blackhole_cow_metrics,
2717 .neigh_lookup = ipv4_neigh_lookup,
2718 };
2719
2720 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2721 {
2722 struct rtable *ort = (struct rtable *) dst_orig;
2723 struct rtable *rt;
2724
2725 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2726 if (rt) {
2727 struct dst_entry *new = &rt->dst;
2728
2729 new->__use = 1;
2730 new->input = dst_discard;
2731 new->output = dst_discard_out;
2732
2733 new->dev = net->loopback_dev;
2734 if (new->dev)
2735 dev_hold(new->dev);
2736
2737 rt->rt_is_input = ort->rt_is_input;
2738 rt->rt_iif = ort->rt_iif;
2739 rt->rt_pmtu = ort->rt_pmtu;
2740 rt->rt_mtu_locked = ort->rt_mtu_locked;
2741
2742 rt->rt_genid = rt_genid_ipv4(net);
2743 rt->rt_flags = ort->rt_flags;
2744 rt->rt_type = ort->rt_type;
2745 rt->rt_uses_gateway = ort->rt_uses_gateway;
2746 rt->rt_gw_family = ort->rt_gw_family;
2747 if (rt->rt_gw_family == AF_INET)
2748 rt->rt_gw4 = ort->rt_gw4;
2749 else if (rt->rt_gw_family == AF_INET6)
2750 rt->rt_gw6 = ort->rt_gw6;
2751
2752 INIT_LIST_HEAD(&rt->rt_uncached);
2753 }
2754
2755 dst_release(dst_orig);
2756
2757 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2758 }
2759
2760 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2761 const struct sock *sk)
2762 {
2763 struct rtable *rt = __ip_route_output_key(net, flp4);
2764
2765 if (IS_ERR(rt))
2766 return rt;
2767
2768 if (flp4->flowi4_proto)
2769 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2770 flowi4_to_flowi(flp4),
2771 sk, 0);
2772
2773 return rt;
2774 }
2775 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2776
2777 /* called with rcu_read_lock held */
2778 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2779 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2780 struct sk_buff *skb, u32 portid, u32 seq,
2781 unsigned int flags)
2782 {
2783 struct rtmsg *r;
2784 struct nlmsghdr *nlh;
2785 unsigned long expires = 0;
2786 u32 error;
2787 u32 metrics[RTAX_MAX];
2788
2789 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2790 if (!nlh)
2791 return -EMSGSIZE;
2792
2793 r = nlmsg_data(nlh);
2794 r->rtm_family = AF_INET;
2795 r->rtm_dst_len = 32;
2796 r->rtm_src_len = 0;
2797 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2798 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2799 if (nla_put_u32(skb, RTA_TABLE, table_id))
2800 goto nla_put_failure;
2801 r->rtm_type = rt->rt_type;
2802 r->rtm_scope = RT_SCOPE_UNIVERSE;
2803 r->rtm_protocol = RTPROT_UNSPEC;
2804 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2805 if (rt->rt_flags & RTCF_NOTIFY)
2806 r->rtm_flags |= RTM_F_NOTIFY;
2807 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2808 r->rtm_flags |= RTCF_DOREDIRECT;
2809
2810 if (nla_put_in_addr(skb, RTA_DST, dst))
2811 goto nla_put_failure;
2812 if (src) {
2813 r->rtm_src_len = 32;
2814 if (nla_put_in_addr(skb, RTA_SRC, src))
2815 goto nla_put_failure;
2816 }
2817 if (rt->dst.dev &&
2818 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2819 goto nla_put_failure;
2820 #ifdef CONFIG_IP_ROUTE_CLASSID
2821 if (rt->dst.tclassid &&
2822 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2823 goto nla_put_failure;
2824 #endif
2825 if (fl4 && !rt_is_input_route(rt) &&
2826 fl4->saddr != src) {
2827 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2828 goto nla_put_failure;
2829 }
2830 if (rt->rt_uses_gateway) {
2831 if (rt->rt_gw_family == AF_INET &&
2832 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2833 goto nla_put_failure;
2834 } else if (rt->rt_gw_family == AF_INET6) {
2835 int alen = sizeof(struct in6_addr);
2836 struct nlattr *nla;
2837 struct rtvia *via;
2838
2839 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2840 if (!nla)
2841 goto nla_put_failure;
2842
2843 via = nla_data(nla);
2844 via->rtvia_family = AF_INET6;
2845 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2846 }
2847 }
2848
2849 expires = rt->dst.expires;
2850 if (expires) {
2851 unsigned long now = jiffies;
2852
2853 if (time_before(now, expires))
2854 expires -= now;
2855 else
2856 expires = 0;
2857 }
2858
2859 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2860 if (rt->rt_pmtu && expires)
2861 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2862 if (rt->rt_mtu_locked && expires)
2863 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2864 if (rtnetlink_put_metrics(skb, metrics) < 0)
2865 goto nla_put_failure;
2866
2867 if (fl4) {
2868 if (fl4->flowi4_mark &&
2869 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
2870 goto nla_put_failure;
2871
2872 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
2873 nla_put_u32(skb, RTA_UID,
2874 from_kuid_munged(current_user_ns(),
2875 fl4->flowi4_uid)))
2876 goto nla_put_failure;
2877
2878 if (rt_is_input_route(rt)) {
2879 #ifdef CONFIG_IP_MROUTE
2880 if (ipv4_is_multicast(dst) &&
2881 !ipv4_is_local_multicast(dst) &&
2882 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
2883 int err = ipmr_get_route(net, skb,
2884 fl4->saddr, fl4->daddr,
2885 r, portid);
2886
2887 if (err <= 0) {
2888 if (err == 0)
2889 return 0;
2890 goto nla_put_failure;
2891 }
2892 } else
2893 #endif
2894 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
2895 goto nla_put_failure;
2896 }
2897 }
2898
2899 error = rt->dst.error;
2900
2901 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
2902 goto nla_put_failure;
2903
2904 nlmsg_end(skb, nlh);
2905 return 0;
2906
2907 nla_put_failure:
2908 nlmsg_cancel(skb, nlh);
2909 return -EMSGSIZE;
2910 }
2911
2912 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
2913 struct netlink_callback *cb, u32 table_id,
2914 struct fnhe_hash_bucket *bucket, int genid,
2915 int *fa_index, int fa_start, unsigned int flags)
2916 {
2917 int i;
2918
2919 for (i = 0; i < FNHE_HASH_SIZE; i++) {
2920 struct fib_nh_exception *fnhe;
2921
2922 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
2923 fnhe = rcu_dereference(fnhe->fnhe_next)) {
2924 struct rtable *rt;
2925 int err;
2926
2927 if (*fa_index < fa_start)
2928 goto next;
2929
2930 if (fnhe->fnhe_genid != genid)
2931 goto next;
2932
2933 if (fnhe->fnhe_expires &&
2934 time_after(jiffies, fnhe->fnhe_expires))
2935 goto next;
2936
2937 rt = rcu_dereference(fnhe->fnhe_rth_input);
2938 if (!rt)
2939 rt = rcu_dereference(fnhe->fnhe_rth_output);
2940 if (!rt)
2941 goto next;
2942
2943 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
2944 table_id, NULL, skb,
2945 NETLINK_CB(cb->skb).portid,
2946 cb->nlh->nlmsg_seq, flags);
2947 if (err)
2948 return err;
2949 next:
2950 (*fa_index)++;
2951 }
2952 }
2953
2954 return 0;
2955 }
2956
2957 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
2958 u32 table_id, struct fib_info *fi,
2959 int *fa_index, int fa_start, unsigned int flags)
2960 {
2961 struct net *net = sock_net(cb->skb->sk);
2962 int nhsel, genid = fnhe_genid(net);
2963
2964 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
2965 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
2966 struct fnhe_hash_bucket *bucket;
2967 int err;
2968
2969 if (nhc->nhc_flags & RTNH_F_DEAD)
2970 continue;
2971
2972 rcu_read_lock();
2973 bucket = rcu_dereference(nhc->nhc_exceptions);
2974 err = 0;
2975 if (bucket)
2976 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
2977 genid, fa_index, fa_start,
2978 flags);
2979 rcu_read_unlock();
2980 if (err)
2981 return err;
2982 }
2983
2984 return 0;
2985 }
2986
2987 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
2988 u8 ip_proto, __be16 sport,
2989 __be16 dport)
2990 {
2991 struct sk_buff *skb;
2992 struct iphdr *iph;
2993
2994 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2995 if (!skb)
2996 return NULL;
2997
2998 /* Reserve room for dummy headers, this skb can pass
2999 * through good chunk of routing engine.
3000 */
3001 skb_reset_mac_header(skb);
3002 skb_reset_network_header(skb);
3003 skb->protocol = htons(ETH_P_IP);
3004 iph = skb_put(skb, sizeof(struct iphdr));
3005 iph->protocol = ip_proto;
3006 iph->saddr = src;
3007 iph->daddr = dst;
3008 iph->version = 0x4;
3009 iph->frag_off = 0;
3010 iph->ihl = 0x5;
3011 skb_set_transport_header(skb, skb->len);
3012
3013 switch (iph->protocol) {
3014 case IPPROTO_UDP: {
3015 struct udphdr *udph;
3016
3017 udph = skb_put_zero(skb, sizeof(struct udphdr));
3018 udph->source = sport;
3019 udph->dest = dport;
3020 udph->len = sizeof(struct udphdr);
3021 udph->check = 0;
3022 break;
3023 }
3024 case IPPROTO_TCP: {
3025 struct tcphdr *tcph;
3026
3027 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3028 tcph->source = sport;
3029 tcph->dest = dport;
3030 tcph->doff = sizeof(struct tcphdr) / 4;
3031 tcph->rst = 1;
3032 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3033 src, dst, 0);
3034 break;
3035 }
3036 case IPPROTO_ICMP: {
3037 struct icmphdr *icmph;
3038
3039 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3040 icmph->type = ICMP_ECHO;
3041 icmph->code = 0;
3042 }
3043 }
3044
3045 return skb;
3046 }
3047
3048 static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3049 const struct nlmsghdr *nlh,
3050 struct nlattr **tb,
3051 struct netlink_ext_ack *extack)
3052 {
3053 struct rtmsg *rtm;
3054 int i, err;
3055
3056 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3057 NL_SET_ERR_MSG(extack,
3058 "ipv4: Invalid header for route get request");
3059 return -EINVAL;
3060 }
3061
3062 if (!netlink_strict_get_check(skb))
3063 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3064 rtm_ipv4_policy, extack);
3065
3066 rtm = nlmsg_data(nlh);
3067 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3068 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3069 rtm->rtm_table || rtm->rtm_protocol ||
3070 rtm->rtm_scope || rtm->rtm_type) {
3071 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3072 return -EINVAL;
3073 }
3074
3075 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3076 RTM_F_LOOKUP_TABLE |
3077 RTM_F_FIB_MATCH)) {
3078 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3079 return -EINVAL;
3080 }
3081
3082 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3083 rtm_ipv4_policy, extack);
3084 if (err)
3085 return err;
3086
3087 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3088 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3089 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3090 return -EINVAL;
3091 }
3092
3093 for (i = 0; i <= RTA_MAX; i++) {
3094 if (!tb[i])
3095 continue;
3096
3097 switch (i) {
3098 case RTA_IIF:
3099 case RTA_OIF:
3100 case RTA_SRC:
3101 case RTA_DST:
3102 case RTA_IP_PROTO:
3103 case RTA_SPORT:
3104 case RTA_DPORT:
3105 case RTA_MARK:
3106 case RTA_UID:
3107 break;
3108 default:
3109 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3110 return -EINVAL;
3111 }
3112 }
3113
3114 return 0;
3115 }
3116
3117 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3118 struct netlink_ext_ack *extack)
3119 {
3120 struct net *net = sock_net(in_skb->sk);
3121 struct nlattr *tb[RTA_MAX+1];
3122 u32 table_id = RT_TABLE_MAIN;
3123 __be16 sport = 0, dport = 0;
3124 struct fib_result res = {};
3125 u8 ip_proto = IPPROTO_UDP;
3126 struct rtable *rt = NULL;
3127 struct sk_buff *skb;
3128 struct rtmsg *rtm;
3129 struct flowi4 fl4 = {};
3130 __be32 dst = 0;
3131 __be32 src = 0;
3132 kuid_t uid;
3133 u32 iif;
3134 int err;
3135 int mark;
3136
3137 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3138 if (err < 0)
3139 return err;
3140
3141 rtm = nlmsg_data(nlh);
3142 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3143 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3144 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3145 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3146 if (tb[RTA_UID])
3147 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3148 else
3149 uid = (iif ? INVALID_UID : current_uid());
3150
3151 if (tb[RTA_IP_PROTO]) {
3152 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3153 &ip_proto, AF_INET, extack);
3154 if (err)
3155 return err;
3156 }
3157
3158 if (tb[RTA_SPORT])
3159 sport = nla_get_be16(tb[RTA_SPORT]);
3160
3161 if (tb[RTA_DPORT])
3162 dport = nla_get_be16(tb[RTA_DPORT]);
3163
3164 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3165 if (!skb)
3166 return -ENOBUFS;
3167
3168 fl4.daddr = dst;
3169 fl4.saddr = src;
3170 fl4.flowi4_tos = rtm->rtm_tos;
3171 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3172 fl4.flowi4_mark = mark;
3173 fl4.flowi4_uid = uid;
3174 if (sport)
3175 fl4.fl4_sport = sport;
3176 if (dport)
3177 fl4.fl4_dport = dport;
3178 fl4.flowi4_proto = ip_proto;
3179
3180 rcu_read_lock();
3181
3182 if (iif) {
3183 struct net_device *dev;
3184
3185 dev = dev_get_by_index_rcu(net, iif);
3186 if (!dev) {
3187 err = -ENODEV;
3188 goto errout_rcu;
3189 }
3190
3191 fl4.flowi4_iif = iif; /* for rt_fill_info */
3192 skb->dev = dev;
3193 skb->mark = mark;
3194 err = ip_route_input_rcu(skb, dst, src, rtm->rtm_tos,
3195 dev, &res);
3196
3197 rt = skb_rtable(skb);
3198 if (err == 0 && rt->dst.error)
3199 err = -rt->dst.error;
3200 } else {
3201 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3202 skb->dev = net->loopback_dev;
3203 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3204 err = 0;
3205 if (IS_ERR(rt))
3206 err = PTR_ERR(rt);
3207 else
3208 skb_dst_set(skb, &rt->dst);
3209 }
3210
3211 if (err)
3212 goto errout_rcu;
3213
3214 if (rtm->rtm_flags & RTM_F_NOTIFY)
3215 rt->rt_flags |= RTCF_NOTIFY;
3216
3217 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3218 table_id = res.table ? res.table->tb_id : 0;
3219
3220 /* reset skb for netlink reply msg */
3221 skb_trim(skb, 0);
3222 skb_reset_network_header(skb);
3223 skb_reset_transport_header(skb);
3224 skb_reset_mac_header(skb);
3225
3226 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3227 struct fib_rt_info fri;
3228
3229 if (!res.fi) {
3230 err = fib_props[res.type].error;
3231 if (!err)
3232 err = -EHOSTUNREACH;
3233 goto errout_rcu;
3234 }
3235 fri.fi = res.fi;
3236 fri.tb_id = table_id;
3237 fri.dst = res.prefix;
3238 fri.dst_len = res.prefixlen;
3239 fri.tos = fl4.flowi4_tos;
3240 fri.type = rt->rt_type;
3241 fri.offload = 0;
3242 fri.trap = 0;
3243 if (res.fa_head) {
3244 struct fib_alias *fa;
3245
3246 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3247 u8 slen = 32 - fri.dst_len;
3248
3249 if (fa->fa_slen == slen &&
3250 fa->tb_id == fri.tb_id &&
3251 fa->fa_tos == fri.tos &&
3252 fa->fa_info == res.fi &&
3253 fa->fa_type == fri.type) {
3254 fri.offload = fa->offload;
3255 fri.trap = fa->trap;
3256 break;
3257 }
3258 }
3259 }
3260 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3261 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3262 } else {
3263 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3264 NETLINK_CB(in_skb).portid,
3265 nlh->nlmsg_seq, 0);
3266 }
3267 if (err < 0)
3268 goto errout_rcu;
3269
3270 rcu_read_unlock();
3271
3272 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3273
3274 errout_free:
3275 return err;
3276 errout_rcu:
3277 rcu_read_unlock();
3278 kfree_skb(skb);
3279 goto errout_free;
3280 }
3281
3282 void ip_rt_multicast_event(struct in_device *in_dev)
3283 {
3284 rt_cache_flush(dev_net(in_dev->dev));
3285 }
3286
3287 #ifdef CONFIG_SYSCTL
3288 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3289 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3290 static int ip_rt_gc_elasticity __read_mostly = 8;
3291 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3292
3293 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3294 void __user *buffer,
3295 size_t *lenp, loff_t *ppos)
3296 {
3297 struct net *net = (struct net *)__ctl->extra1;
3298
3299 if (write) {
3300 rt_cache_flush(net);
3301 fnhe_genid_bump(net);
3302 return 0;
3303 }
3304
3305 return -EINVAL;
3306 }
3307
3308 static struct ctl_table ipv4_route_table[] = {
3309 {
3310 .procname = "gc_thresh",
3311 .data = &ipv4_dst_ops.gc_thresh,
3312 .maxlen = sizeof(int),
3313 .mode = 0644,
3314 .proc_handler = proc_dointvec,
3315 },
3316 {
3317 .procname = "max_size",
3318 .data = &ip_rt_max_size,
3319 .maxlen = sizeof(int),
3320 .mode = 0644,
3321 .proc_handler = proc_dointvec,
3322 },
3323 {
3324 /* Deprecated. Use gc_min_interval_ms */
3325
3326 .procname = "gc_min_interval",
3327 .data = &ip_rt_gc_min_interval,
3328 .maxlen = sizeof(int),
3329 .mode = 0644,
3330 .proc_handler = proc_dointvec_jiffies,
3331 },
3332 {
3333 .procname = "gc_min_interval_ms",
3334 .data = &ip_rt_gc_min_interval,
3335 .maxlen = sizeof(int),
3336 .mode = 0644,
3337 .proc_handler = proc_dointvec_ms_jiffies,
3338 },
3339 {
3340 .procname = "gc_timeout",
3341 .data = &ip_rt_gc_timeout,
3342 .maxlen = sizeof(int),
3343 .mode = 0644,
3344 .proc_handler = proc_dointvec_jiffies,
3345 },
3346 {
3347 .procname = "gc_interval",
3348 .data = &ip_rt_gc_interval,
3349 .maxlen = sizeof(int),
3350 .mode = 0644,
3351 .proc_handler = proc_dointvec_jiffies,
3352 },
3353 {
3354 .procname = "redirect_load",
3355 .data = &ip_rt_redirect_load,
3356 .maxlen = sizeof(int),
3357 .mode = 0644,
3358 .proc_handler = proc_dointvec,
3359 },
3360 {
3361 .procname = "redirect_number",
3362 .data = &ip_rt_redirect_number,
3363 .maxlen = sizeof(int),
3364 .mode = 0644,
3365 .proc_handler = proc_dointvec,
3366 },
3367 {
3368 .procname = "redirect_silence",
3369 .data = &ip_rt_redirect_silence,
3370 .maxlen = sizeof(int),
3371 .mode = 0644,
3372 .proc_handler = proc_dointvec,
3373 },
3374 {
3375 .procname = "error_cost",
3376 .data = &ip_rt_error_cost,
3377 .maxlen = sizeof(int),
3378 .mode = 0644,
3379 .proc_handler = proc_dointvec,
3380 },
3381 {
3382 .procname = "error_burst",
3383 .data = &ip_rt_error_burst,
3384 .maxlen = sizeof(int),
3385 .mode = 0644,
3386 .proc_handler = proc_dointvec,
3387 },
3388 {
3389 .procname = "gc_elasticity",
3390 .data = &ip_rt_gc_elasticity,
3391 .maxlen = sizeof(int),
3392 .mode = 0644,
3393 .proc_handler = proc_dointvec,
3394 },
3395 {
3396 .procname = "mtu_expires",
3397 .data = &ip_rt_mtu_expires,
3398 .maxlen = sizeof(int),
3399 .mode = 0644,
3400 .proc_handler = proc_dointvec_jiffies,
3401 },
3402 {
3403 .procname = "min_pmtu",
3404 .data = &ip_rt_min_pmtu,
3405 .maxlen = sizeof(int),
3406 .mode = 0644,
3407 .proc_handler = proc_dointvec_minmax,
3408 .extra1 = &ip_min_valid_pmtu,
3409 },
3410 {
3411 .procname = "min_adv_mss",
3412 .data = &ip_rt_min_advmss,
3413 .maxlen = sizeof(int),
3414 .mode = 0644,
3415 .proc_handler = proc_dointvec,
3416 },
3417 { }
3418 };
3419
3420 static const char ipv4_route_flush_procname[] = "flush";
3421
3422 static struct ctl_table ipv4_route_flush_table[] = {
3423 {
3424 .procname = ipv4_route_flush_procname,
3425 .maxlen = sizeof(int),
3426 .mode = 0200,
3427 .proc_handler = ipv4_sysctl_rtcache_flush,
3428 },
3429 { },
3430 };
3431
3432 static __net_init int sysctl_route_net_init(struct net *net)
3433 {
3434 struct ctl_table *tbl;
3435
3436 tbl = ipv4_route_flush_table;
3437 if (!net_eq(net, &init_net)) {
3438 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3439 if (!tbl)
3440 goto err_dup;
3441
3442 /* Don't export non-whitelisted sysctls to unprivileged users */
3443 if (net->user_ns != &init_user_ns) {
3444 if (tbl[0].procname != ipv4_route_flush_procname)
3445 tbl[0].procname = NULL;
3446 }
3447 }
3448 tbl[0].extra1 = net;
3449
3450 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3451 if (!net->ipv4.route_hdr)
3452 goto err_reg;
3453 return 0;
3454
3455 err_reg:
3456 if (tbl != ipv4_route_flush_table)
3457 kfree(tbl);
3458 err_dup:
3459 return -ENOMEM;
3460 }
3461
3462 static __net_exit void sysctl_route_net_exit(struct net *net)
3463 {
3464 struct ctl_table *tbl;
3465
3466 tbl = net->ipv4.route_hdr->ctl_table_arg;
3467 unregister_net_sysctl_table(net->ipv4.route_hdr);
3468 BUG_ON(tbl == ipv4_route_flush_table);
3469 kfree(tbl);
3470 }
3471
3472 static __net_initdata struct pernet_operations sysctl_route_ops = {
3473 .init = sysctl_route_net_init,
3474 .exit = sysctl_route_net_exit,
3475 };
3476 #endif
3477
3478 static __net_init int rt_genid_init(struct net *net)
3479 {
3480 atomic_set(&net->ipv4.rt_genid, 0);
3481 atomic_set(&net->fnhe_genid, 0);
3482 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3483 return 0;
3484 }
3485
3486 static __net_initdata struct pernet_operations rt_genid_ops = {
3487 .init = rt_genid_init,
3488 };
3489
3490 static int __net_init ipv4_inetpeer_init(struct net *net)
3491 {
3492 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3493
3494 if (!bp)
3495 return -ENOMEM;
3496 inet_peer_base_init(bp);
3497 net->ipv4.peers = bp;
3498 return 0;
3499 }
3500
3501 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3502 {
3503 struct inet_peer_base *bp = net->ipv4.peers;
3504
3505 net->ipv4.peers = NULL;
3506 inetpeer_invalidate_tree(bp);
3507 kfree(bp);
3508 }
3509
3510 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3511 .init = ipv4_inetpeer_init,
3512 .exit = ipv4_inetpeer_exit,
3513 };
3514
3515 #ifdef CONFIG_IP_ROUTE_CLASSID
3516 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3517 #endif /* CONFIG_IP_ROUTE_CLASSID */
3518
3519 int __init ip_rt_init(void)
3520 {
3521 int cpu;
3522
3523 ip_idents = kmalloc_array(IP_IDENTS_SZ, sizeof(*ip_idents),
3524 GFP_KERNEL);
3525 if (!ip_idents)
3526 panic("IP: failed to allocate ip_idents\n");
3527
3528 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents));
3529
3530 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL);
3531 if (!ip_tstamps)
3532 panic("IP: failed to allocate ip_tstamps\n");
3533
3534 for_each_possible_cpu(cpu) {
3535 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3536
3537 INIT_LIST_HEAD(&ul->head);
3538 spin_lock_init(&ul->lock);
3539 }
3540 #ifdef CONFIG_IP_ROUTE_CLASSID
3541 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3542 if (!ip_rt_acct)
3543 panic("IP: failed to allocate ip_rt_acct\n");
3544 #endif
3545
3546 ipv4_dst_ops.kmem_cachep =
3547 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3548 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3549
3550 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3551
3552 if (dst_entries_init(&ipv4_dst_ops) < 0)
3553 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3554
3555 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3556 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3557
3558 ipv4_dst_ops.gc_thresh = ~0;
3559 ip_rt_max_size = INT_MAX;
3560
3561 devinet_init();
3562 ip_fib_init();
3563
3564 if (ip_rt_proc_init())
3565 pr_err("Unable to create route proc files\n");
3566 #ifdef CONFIG_XFRM
3567 xfrm_init();
3568 xfrm4_init();
3569 #endif
3570 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3571 RTNL_FLAG_DOIT_UNLOCKED);
3572
3573 #ifdef CONFIG_SYSCTL
3574 register_pernet_subsys(&sysctl_route_ops);
3575 #endif
3576 register_pernet_subsys(&rt_genid_ops);
3577 register_pernet_subsys(&ipv4_inetpeer_ops);
3578 return 0;
3579 }
3580
3581 #ifdef CONFIG_SYSCTL
3582 /*
3583 * We really need to sanitize the damn ipv4 init order, then all
3584 * this nonsense will go away.
3585 */
3586 void __init ip_static_sysctl_init(void)
3587 {
3588 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3589 }
3590 #endif
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