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