1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * ROUTE - implementation of the IP router.
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Alan Cox, <gw4pts@gw4pts.ampr.org>
12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
14 *
15 * Fixes:
16 * Alan Cox : Verify area fixes.
17 * Alan Cox : cli() protects routing changes
18 * Rui Oliveira : ICMP routing table updates
19 * (rco@di.uminho.pt) Routing table insertion and update
20 * Linus Torvalds : Rewrote bits to be sensible
21 * Alan Cox : Added BSD route gw semantics
22 * Alan Cox : Super /proc >4K
23 * Alan Cox : MTU in route table
24 * Alan Cox : MSS actually. Also added the window
25 * clamper.
26 * Sam Lantinga : Fixed route matching in rt_del()
27 * Alan Cox : Routing cache support.
28 * Alan Cox : Removed compatibility cruft.
29 * Alan Cox : RTF_REJECT support.
30 * Alan Cox : TCP irtt support.
31 * Jonathan Naylor : Added Metric support.
32 * Miquel van Smoorenburg : BSD API fixes.
33 * Miquel van Smoorenburg : Metrics.
34 * Alan Cox : Use __u32 properly
35 * Alan Cox : Aligned routing errors more closely with BSD
36 * our system is still very different.
37 * Alan Cox : Faster /proc handling
38 * Alexey Kuznetsov : Massive rework to support tree based routing,
39 * routing caches and better behaviour.
40 *
41 * Olaf Erb : irtt wasn't being copied right.
42 * Bjorn Ekwall : Kerneld route support.
43 * Alan Cox : Multicast fixed (I hope)
44 * Pavel Krauz : Limited broadcast fixed
45 * Mike McLagan : Routing by source
46 * Alexey Kuznetsov : End of old history. Split to fib.c and
47 * route.c and rewritten from scratch.
48 * Andi Kleen : Load-limit warning messages.
49 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
53 * Marc Boucher : routing by fwmark
54 * Robert Olsson : Added rt_cache statistics
55 * Arnaldo C. Melo : Convert proc stuff to seq_file
56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
58 * Ilia Sotnikov : Removed TOS from hash calculations
59 */
60
61 #define pr_fmt(fmt) "IPv4: " fmt
62
63 #include <linux/module.h>
64 #include <linux/uaccess.h>
65 #include <linux/bitops.h>
66 #include <linux/types.h>
67 #include <linux/kernel.h>
68 #include <linux/mm.h>
69 #include <linux/memblock.h>
70 #include <linux/string.h>
71 #include <linux/socket.h>
72 #include <linux/sockios.h>
73 #include <linux/errno.h>
74 #include <linux/in.h>
75 #include <linux/inet.h>
76 #include <linux/netdevice.h>
77 #include <linux/proc_fs.h>
78 #include <linux/init.h>
79 #include <linux/skbuff.h>
80 #include <linux/inetdevice.h>
81 #include <linux/igmp.h>
82 #include <linux/pkt_sched.h>
83 #include <linux/mroute.h>
84 #include <linux/netfilter_ipv4.h>
85 #include <linux/random.h>
86 #include <linux/rcupdate.h>
87 #include <linux/times.h>
88 #include <linux/slab.h>
89 #include <linux/jhash.h>
90 #include <net/dst.h>
91 #include <net/dst_metadata.h>
92 #include <net/net_namespace.h>
93 #include <net/protocol.h>
94 #include <net/ip.h>
95 #include <net/route.h>
96 #include <net/inetpeer.h>
97 #include <net/sock.h>
98 #include <net/ip_fib.h>
99 #include <net/nexthop.h>
100 #include <net/arp.h>
101 #include <net/tcp.h>
102 #include <net/icmp.h>
103 #include <net/xfrm.h>
104 #include <net/lwtunnel.h>
105 #include <net/netevent.h>
106 #include <net/rtnetlink.h>
107 #ifdef CONFIG_SYSCTL
108 #include <linux/sysctl.h>
109 #endif
110 #include <net/secure_seq.h>
111 #include <net/ip_tunnels.h>
112 #include <net/l3mdev.h>
113
114 #include "fib_lookup.h"
115
116 #define RT_FL_TOS(oldflp4) \
117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
118
119 #define RT_GC_TIMEOUT (300*HZ)
120
121 static int ip_rt_max_size;
122 static int ip_rt_redirect_number __read_mostly = 9;
123 static int ip_rt_redirect_load __read_mostly = HZ / 50;
124 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
125 static int ip_rt_error_cost __read_mostly = HZ;
126 static int ip_rt_error_burst __read_mostly = 5 * HZ;
127 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
128 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
129 static int ip_rt_min_advmss __read_mostly = 256;
130
131 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
132
133 /*
134 * Interface to generic destination cache.
135 */
136
137 INDIRECT_CALLABLE_SCOPE
138 struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
139 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
140 INDIRECT_CALLABLE_SCOPE
141 unsigned int ipv4_mtu(const struct dst_entry *dst);
142 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
143 static void ipv4_link_failure(struct sk_buff *skb);
144 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb, u32 mtu,
146 bool confirm_neigh);
147 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
148 struct sk_buff *skb);
149 static void ipv4_dst_destroy(struct dst_entry *dst);
150
ipv4_cow_metrics(struct dst_entry * dst,unsigned long old)151 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
152 {
153 WARN_ON(1);
154 return NULL;
155 }
156
157 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
158 struct sk_buff *skb,
159 const void *daddr);
160 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
161
162 static struct dst_ops ipv4_dst_ops = {
163 .family = AF_INET,
164 .check = ipv4_dst_check,
165 .default_advmss = ipv4_default_advmss,
166 .mtu = ipv4_mtu,
167 .cow_metrics = ipv4_cow_metrics,
168 .destroy = ipv4_dst_destroy,
169 .negative_advice = ipv4_negative_advice,
170 .link_failure = ipv4_link_failure,
171 .update_pmtu = ip_rt_update_pmtu,
172 .redirect = ip_do_redirect,
173 .local_out = __ip_local_out,
174 .neigh_lookup = ipv4_neigh_lookup,
175 .confirm_neigh = ipv4_confirm_neigh,
176 };
177
178 #define ECN_OR_COST(class) TC_PRIO_##class
179
180 const __u8 ip_tos2prio[16] = {
181 TC_PRIO_BESTEFFORT,
182 ECN_OR_COST(BESTEFFORT),
183 TC_PRIO_BESTEFFORT,
184 ECN_OR_COST(BESTEFFORT),
185 TC_PRIO_BULK,
186 ECN_OR_COST(BULK),
187 TC_PRIO_BULK,
188 ECN_OR_COST(BULK),
189 TC_PRIO_INTERACTIVE,
190 ECN_OR_COST(INTERACTIVE),
191 TC_PRIO_INTERACTIVE,
192 ECN_OR_COST(INTERACTIVE),
193 TC_PRIO_INTERACTIVE_BULK,
194 ECN_OR_COST(INTERACTIVE_BULK),
195 TC_PRIO_INTERACTIVE_BULK,
196 ECN_OR_COST(INTERACTIVE_BULK)
197 };
198 EXPORT_SYMBOL(ip_tos2prio);
199
200 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
201 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
202
203 #ifdef CONFIG_PROC_FS
rt_cache_seq_start(struct seq_file * seq,loff_t * pos)204 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
205 {
206 if (*pos)
207 return NULL;
208 return SEQ_START_TOKEN;
209 }
210
rt_cache_seq_next(struct seq_file * seq,void * v,loff_t * pos)211 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
212 {
213 ++*pos;
214 return NULL;
215 }
216
rt_cache_seq_stop(struct seq_file * seq,void * v)217 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
218 {
219 }
220
rt_cache_seq_show(struct seq_file * seq,void * v)221 static int rt_cache_seq_show(struct seq_file *seq, void *v)
222 {
223 if (v == SEQ_START_TOKEN)
224 seq_printf(seq, "%-127s\n",
225 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
226 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
227 "HHUptod\tSpecDst");
228 return 0;
229 }
230
231 static const struct seq_operations rt_cache_seq_ops = {
232 .start = rt_cache_seq_start,
233 .next = rt_cache_seq_next,
234 .stop = rt_cache_seq_stop,
235 .show = rt_cache_seq_show,
236 };
237
rt_cpu_seq_start(struct seq_file * seq,loff_t * pos)238 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
239 {
240 int cpu;
241
242 if (*pos == 0)
243 return SEQ_START_TOKEN;
244
245 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
246 if (!cpu_possible(cpu))
247 continue;
248 *pos = cpu+1;
249 return &per_cpu(rt_cache_stat, cpu);
250 }
251 return NULL;
252 }
253
rt_cpu_seq_next(struct seq_file * seq,void * v,loff_t * pos)254 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
255 {
256 int cpu;
257
258 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
259 if (!cpu_possible(cpu))
260 continue;
261 *pos = cpu+1;
262 return &per_cpu(rt_cache_stat, cpu);
263 }
264 (*pos)++;
265 return NULL;
266
267 }
268
rt_cpu_seq_stop(struct seq_file * seq,void * v)269 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
270 {
271
272 }
273
rt_cpu_seq_show(struct seq_file * seq,void * v)274 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
275 {
276 struct rt_cache_stat *st = v;
277
278 if (v == SEQ_START_TOKEN) {
279 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");
280 return 0;
281 }
282
283 seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x "
284 "%08x %08x %08x %08x %08x %08x "
285 "%08x %08x %08x %08x\n",
286 dst_entries_get_slow(&ipv4_dst_ops),
287 0, /* st->in_hit */
288 st->in_slow_tot,
289 st->in_slow_mc,
290 st->in_no_route,
291 st->in_brd,
292 st->in_martian_dst,
293 st->in_martian_src,
294
295 0, /* st->out_hit */
296 st->out_slow_tot,
297 st->out_slow_mc,
298
299 0, /* st->gc_total */
300 0, /* st->gc_ignored */
301 0, /* st->gc_goal_miss */
302 0, /* st->gc_dst_overflow */
303 0, /* st->in_hlist_search */
304 0 /* st->out_hlist_search */
305 );
306 return 0;
307 }
308
309 static const struct seq_operations rt_cpu_seq_ops = {
310 .start = rt_cpu_seq_start,
311 .next = rt_cpu_seq_next,
312 .stop = rt_cpu_seq_stop,
313 .show = rt_cpu_seq_show,
314 };
315
316 #ifdef CONFIG_IP_ROUTE_CLASSID
rt_acct_proc_show(struct seq_file * m,void * v)317 static int rt_acct_proc_show(struct seq_file *m, void *v)
318 {
319 struct ip_rt_acct *dst, *src;
320 unsigned int i, j;
321
322 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
323 if (!dst)
324 return -ENOMEM;
325
326 for_each_possible_cpu(i) {
327 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
328 for (j = 0; j < 256; j++) {
329 dst[j].o_bytes += src[j].o_bytes;
330 dst[j].o_packets += src[j].o_packets;
331 dst[j].i_bytes += src[j].i_bytes;
332 dst[j].i_packets += src[j].i_packets;
333 }
334 }
335
336 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
337 kfree(dst);
338 return 0;
339 }
340 #endif
341
ip_rt_do_proc_init(struct net * net)342 static int __net_init ip_rt_do_proc_init(struct net *net)
343 {
344 struct proc_dir_entry *pde;
345
346 pde = proc_create_seq("rt_cache", 0444, net->proc_net,
347 &rt_cache_seq_ops);
348 if (!pde)
349 goto err1;
350
351 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
352 &rt_cpu_seq_ops);
353 if (!pde)
354 goto err2;
355
356 #ifdef CONFIG_IP_ROUTE_CLASSID
357 pde = proc_create_single("rt_acct", 0, net->proc_net,
358 rt_acct_proc_show);
359 if (!pde)
360 goto err3;
361 #endif
362 return 0;
363
364 #ifdef CONFIG_IP_ROUTE_CLASSID
365 err3:
366 remove_proc_entry("rt_cache", net->proc_net_stat);
367 #endif
368 err2:
369 remove_proc_entry("rt_cache", net->proc_net);
370 err1:
371 return -ENOMEM;
372 }
373
ip_rt_do_proc_exit(struct net * net)374 static void __net_exit ip_rt_do_proc_exit(struct net *net)
375 {
376 remove_proc_entry("rt_cache", net->proc_net_stat);
377 remove_proc_entry("rt_cache", net->proc_net);
378 #ifdef CONFIG_IP_ROUTE_CLASSID
379 remove_proc_entry("rt_acct", net->proc_net);
380 #endif
381 }
382
383 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
384 .init = ip_rt_do_proc_init,
385 .exit = ip_rt_do_proc_exit,
386 };
387
ip_rt_proc_init(void)388 static int __init ip_rt_proc_init(void)
389 {
390 return register_pernet_subsys(&ip_rt_proc_ops);
391 }
392
393 #else
ip_rt_proc_init(void)394 static inline int ip_rt_proc_init(void)
395 {
396 return 0;
397 }
398 #endif /* CONFIG_PROC_FS */
399
rt_is_expired(const struct rtable * rth)400 static inline bool rt_is_expired(const struct rtable *rth)
401 {
402 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
403 }
404
rt_cache_flush(struct net * net)405 void rt_cache_flush(struct net *net)
406 {
407 rt_genid_bump_ipv4(net);
408 }
409
ipv4_neigh_lookup(const struct dst_entry * dst,struct sk_buff * skb,const void * daddr)410 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
411 struct sk_buff *skb,
412 const void *daddr)
413 {
414 const struct rtable *rt = container_of(dst, struct rtable, dst);
415 struct net_device *dev = dst->dev;
416 struct neighbour *n;
417
418 rcu_read_lock_bh();
419
420 if (likely(rt->rt_gw_family == AF_INET)) {
421 n = ip_neigh_gw4(dev, rt->rt_gw4);
422 } else if (rt->rt_gw_family == AF_INET6) {
423 n = ip_neigh_gw6(dev, &rt->rt_gw6);
424 } else {
425 __be32 pkey;
426
427 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
428 n = ip_neigh_gw4(dev, pkey);
429 }
430
431 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
432 n = NULL;
433
434 rcu_read_unlock_bh();
435
436 return n;
437 }
438
ipv4_confirm_neigh(const struct dst_entry * dst,const void * daddr)439 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
440 {
441 const struct rtable *rt = container_of(dst, struct rtable, dst);
442 struct net_device *dev = dst->dev;
443 const __be32 *pkey = daddr;
444
445 if (rt->rt_gw_family == AF_INET) {
446 pkey = (const __be32 *)&rt->rt_gw4;
447 } else if (rt->rt_gw_family == AF_INET6) {
448 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
449 } else if (!daddr ||
450 (rt->rt_flags &
451 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
452 return;
453 }
454 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
455 }
456
457 /* Hash tables of size 2048..262144 depending on RAM size.
458 * Each bucket uses 8 bytes.
459 */
460 static u32 ip_idents_mask __read_mostly;
461 static atomic_t *ip_idents __read_mostly;
462 static u32 *ip_tstamps __read_mostly;
463
464 /* In order to protect privacy, we add a perturbation to identifiers
465 * if one generator is seldom used. This makes hard for an attacker
466 * to infer how many packets were sent between two points in time.
467 */
ip_idents_reserve(u32 hash,int segs)468 u32 ip_idents_reserve(u32 hash, int segs)
469 {
470 u32 bucket, old, now = (u32)jiffies;
471 atomic_t *p_id;
472 u32 *p_tstamp;
473 u32 delta = 0;
474
475 bucket = hash & ip_idents_mask;
476 p_tstamp = ip_tstamps + bucket;
477 p_id = ip_idents + bucket;
478 old = READ_ONCE(*p_tstamp);
479
480 if (old != now && cmpxchg(p_tstamp, old, now) == old)
481 delta = prandom_u32_max(now - old);
482
483 /* If UBSAN reports an error there, please make sure your compiler
484 * supports -fno-strict-overflow before reporting it that was a bug
485 * in UBSAN, and it has been fixed in GCC-8.
486 */
487 return atomic_add_return(segs + delta, p_id) - segs;
488 }
489 EXPORT_SYMBOL(ip_idents_reserve);
490
__ip_select_ident(struct net * net,struct iphdr * iph,int segs)491 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
492 {
493 u32 hash, id;
494
495 /* Note the following code is not safe, but this is okay. */
496 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
497 get_random_bytes(&net->ipv4.ip_id_key,
498 sizeof(net->ipv4.ip_id_key));
499
500 hash = siphash_3u32((__force u32)iph->daddr,
501 (__force u32)iph->saddr,
502 iph->protocol,
503 &net->ipv4.ip_id_key);
504 id = ip_idents_reserve(hash, segs);
505 iph->id = htons(id);
506 }
507 EXPORT_SYMBOL(__ip_select_ident);
508
__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)509 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
510 const struct sock *sk,
511 const struct iphdr *iph,
512 int oif, u8 tos,
513 u8 prot, u32 mark, int flow_flags)
514 {
515 if (sk) {
516 const struct inet_sock *inet = inet_sk(sk);
517
518 oif = sk->sk_bound_dev_if;
519 mark = sk->sk_mark;
520 tos = RT_CONN_FLAGS(sk);
521 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
522 }
523 flowi4_init_output(fl4, oif, mark, tos,
524 RT_SCOPE_UNIVERSE, prot,
525 flow_flags,
526 iph->daddr, iph->saddr, 0, 0,
527 sock_net_uid(net, sk));
528 }
529
build_skb_flow_key(struct flowi4 * fl4,const struct sk_buff * skb,const struct sock * sk)530 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
531 const struct sock *sk)
532 {
533 const struct net *net = dev_net(skb->dev);
534 const struct iphdr *iph = ip_hdr(skb);
535 int oif = skb->dev->ifindex;
536 u8 tos = RT_TOS(iph->tos);
537 u8 prot = iph->protocol;
538 u32 mark = skb->mark;
539
540 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
541 }
542
build_sk_flow_key(struct flowi4 * fl4,const struct sock * sk)543 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
544 {
545 const struct inet_sock *inet = inet_sk(sk);
546 const struct ip_options_rcu *inet_opt;
547 __be32 daddr = inet->inet_daddr;
548
549 rcu_read_lock();
550 inet_opt = rcu_dereference(inet->inet_opt);
551 if (inet_opt && inet_opt->opt.srr)
552 daddr = inet_opt->opt.faddr;
553 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
554 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
555 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
556 inet_sk_flowi_flags(sk),
557 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
558 rcu_read_unlock();
559 }
560
ip_rt_build_flow_key(struct flowi4 * fl4,const struct sock * sk,const struct sk_buff * skb)561 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
562 const struct sk_buff *skb)
563 {
564 if (skb)
565 build_skb_flow_key(fl4, skb, sk);
566 else
567 build_sk_flow_key(fl4, sk);
568 }
569
570 static DEFINE_SPINLOCK(fnhe_lock);
571
fnhe_flush_routes(struct fib_nh_exception * fnhe)572 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
573 {
574 struct rtable *rt;
575
576 rt = rcu_dereference(fnhe->fnhe_rth_input);
577 if (rt) {
578 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
579 dst_dev_put(&rt->dst);
580 dst_release(&rt->dst);
581 }
582 rt = rcu_dereference(fnhe->fnhe_rth_output);
583 if (rt) {
584 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
585 dst_dev_put(&rt->dst);
586 dst_release(&rt->dst);
587 }
588 }
589
fnhe_remove_oldest(struct fnhe_hash_bucket * hash)590 static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
591 {
592 struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
593 struct fib_nh_exception *fnhe, *oldest = NULL;
594
595 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
596 fnhe = rcu_dereference_protected(*fnhe_p,
597 lockdep_is_held(&fnhe_lock));
598 if (!fnhe)
599 break;
600 if (!oldest ||
601 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
602 oldest = fnhe;
603 oldest_p = fnhe_p;
604 }
605 }
606 fnhe_flush_routes(oldest);
607 *oldest_p = oldest->fnhe_next;
608 kfree_rcu(oldest, rcu);
609 }
610
fnhe_hashfun(__be32 daddr)611 static u32 fnhe_hashfun(__be32 daddr)
612 {
613 static siphash_key_t fnhe_hash_key __read_mostly;
614 u64 hval;
615
616 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
617 hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key);
618 return hash_64(hval, FNHE_HASH_SHIFT);
619 }
620
fill_route_from_fnhe(struct rtable * rt,struct fib_nh_exception * fnhe)621 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
622 {
623 rt->rt_pmtu = fnhe->fnhe_pmtu;
624 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
625 rt->dst.expires = fnhe->fnhe_expires;
626
627 if (fnhe->fnhe_gw) {
628 rt->rt_flags |= RTCF_REDIRECTED;
629 rt->rt_uses_gateway = 1;
630 rt->rt_gw_family = AF_INET;
631 rt->rt_gw4 = fnhe->fnhe_gw;
632 }
633 }
634
update_or_create_fnhe(struct fib_nh_common * nhc,__be32 daddr,__be32 gw,u32 pmtu,bool lock,unsigned long expires)635 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
636 __be32 gw, u32 pmtu, bool lock,
637 unsigned long expires)
638 {
639 struct fnhe_hash_bucket *hash;
640 struct fib_nh_exception *fnhe;
641 struct rtable *rt;
642 u32 genid, hval;
643 unsigned int i;
644 int depth;
645
646 genid = fnhe_genid(dev_net(nhc->nhc_dev));
647 hval = fnhe_hashfun(daddr);
648
649 spin_lock_bh(&fnhe_lock);
650
651 hash = rcu_dereference(nhc->nhc_exceptions);
652 if (!hash) {
653 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
654 if (!hash)
655 goto out_unlock;
656 rcu_assign_pointer(nhc->nhc_exceptions, hash);
657 }
658
659 hash += hval;
660
661 depth = 0;
662 for (fnhe = rcu_dereference(hash->chain); fnhe;
663 fnhe = rcu_dereference(fnhe->fnhe_next)) {
664 if (fnhe->fnhe_daddr == daddr)
665 break;
666 depth++;
667 }
668
669 if (fnhe) {
670 if (fnhe->fnhe_genid != genid)
671 fnhe->fnhe_genid = genid;
672 if (gw)
673 fnhe->fnhe_gw = gw;
674 if (pmtu) {
675 fnhe->fnhe_pmtu = pmtu;
676 fnhe->fnhe_mtu_locked = lock;
677 }
678 fnhe->fnhe_expires = max(1UL, expires);
679 /* Update all cached dsts too */
680 rt = rcu_dereference(fnhe->fnhe_rth_input);
681 if (rt)
682 fill_route_from_fnhe(rt, fnhe);
683 rt = rcu_dereference(fnhe->fnhe_rth_output);
684 if (rt)
685 fill_route_from_fnhe(rt, fnhe);
686 } else {
687 /* Randomize max depth to avoid some side channels attacks. */
688 int max_depth = FNHE_RECLAIM_DEPTH +
689 prandom_u32_max(FNHE_RECLAIM_DEPTH);
690
691 while (depth > max_depth) {
692 fnhe_remove_oldest(hash);
693 depth--;
694 }
695
696 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
697 if (!fnhe)
698 goto out_unlock;
699
700 fnhe->fnhe_next = hash->chain;
701
702 fnhe->fnhe_genid = genid;
703 fnhe->fnhe_daddr = daddr;
704 fnhe->fnhe_gw = gw;
705 fnhe->fnhe_pmtu = pmtu;
706 fnhe->fnhe_mtu_locked = lock;
707 fnhe->fnhe_expires = max(1UL, expires);
708
709 rcu_assign_pointer(hash->chain, fnhe);
710
711 /* Exception created; mark the cached routes for the nexthop
712 * stale, so anyone caching it rechecks if this exception
713 * applies to them.
714 */
715 rt = rcu_dereference(nhc->nhc_rth_input);
716 if (rt)
717 rt->dst.obsolete = DST_OBSOLETE_KILL;
718
719 for_each_possible_cpu(i) {
720 struct rtable __rcu **prt;
721
722 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
723 rt = rcu_dereference(*prt);
724 if (rt)
725 rt->dst.obsolete = DST_OBSOLETE_KILL;
726 }
727 }
728
729 fnhe->fnhe_stamp = jiffies;
730
731 out_unlock:
732 spin_unlock_bh(&fnhe_lock);
733 }
734
__ip_do_redirect(struct rtable * rt,struct sk_buff * skb,struct flowi4 * fl4,bool kill_route)735 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
736 bool kill_route)
737 {
738 __be32 new_gw = icmp_hdr(skb)->un.gateway;
739 __be32 old_gw = ip_hdr(skb)->saddr;
740 struct net_device *dev = skb->dev;
741 struct in_device *in_dev;
742 struct fib_result res;
743 struct neighbour *n;
744 struct net *net;
745
746 switch (icmp_hdr(skb)->code & 7) {
747 case ICMP_REDIR_NET:
748 case ICMP_REDIR_NETTOS:
749 case ICMP_REDIR_HOST:
750 case ICMP_REDIR_HOSTTOS:
751 break;
752
753 default:
754 return;
755 }
756
757 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
758 return;
759
760 in_dev = __in_dev_get_rcu(dev);
761 if (!in_dev)
762 return;
763
764 net = dev_net(dev);
765 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
766 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
767 ipv4_is_zeronet(new_gw))
768 goto reject_redirect;
769
770 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
771 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
772 goto reject_redirect;
773 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
774 goto reject_redirect;
775 } else {
776 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
777 goto reject_redirect;
778 }
779
780 n = __ipv4_neigh_lookup(rt->dst.dev, new_gw);
781 if (!n)
782 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
783 if (!IS_ERR(n)) {
784 if (!(n->nud_state & NUD_VALID)) {
785 neigh_event_send(n, NULL);
786 } else {
787 if (fib_lookup(net, fl4, &res, 0) == 0) {
788 struct fib_nh_common *nhc;
789
790 fib_select_path(net, &res, fl4, skb);
791 nhc = FIB_RES_NHC(res);
792 update_or_create_fnhe(nhc, fl4->daddr, new_gw,
793 0, false,
794 jiffies + ip_rt_gc_timeout);
795 }
796 if (kill_route)
797 rt->dst.obsolete = DST_OBSOLETE_KILL;
798 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
799 }
800 neigh_release(n);
801 }
802 return;
803
804 reject_redirect:
805 #ifdef CONFIG_IP_ROUTE_VERBOSE
806 if (IN_DEV_LOG_MARTIANS(in_dev)) {
807 const struct iphdr *iph = (const struct iphdr *) skb->data;
808 __be32 daddr = iph->daddr;
809 __be32 saddr = iph->saddr;
810
811 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
812 " Advised path = %pI4 -> %pI4\n",
813 &old_gw, dev->name, &new_gw,
814 &saddr, &daddr);
815 }
816 #endif
817 ;
818 }
819
ip_do_redirect(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb)820 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
821 {
822 struct rtable *rt;
823 struct flowi4 fl4;
824 const struct iphdr *iph = (const struct iphdr *) skb->data;
825 struct net *net = dev_net(skb->dev);
826 int oif = skb->dev->ifindex;
827 u8 tos = RT_TOS(iph->tos);
828 u8 prot = iph->protocol;
829 u32 mark = skb->mark;
830
831 rt = (struct rtable *) dst;
832
833 __build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);
834 __ip_do_redirect(rt, skb, &fl4, true);
835 }
836
ipv4_negative_advice(struct dst_entry * dst)837 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
838 {
839 struct rtable *rt = (struct rtable *)dst;
840 struct dst_entry *ret = dst;
841
842 if (rt) {
843 if (dst->obsolete > 0) {
844 ip_rt_put(rt);
845 ret = NULL;
846 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
847 rt->dst.expires) {
848 ip_rt_put(rt);
849 ret = NULL;
850 }
851 }
852 return ret;
853 }
854
855 /*
856 * Algorithm:
857 * 1. The first ip_rt_redirect_number redirects are sent
858 * with exponential backoff, then we stop sending them at all,
859 * assuming that the host ignores our redirects.
860 * 2. If we did not see packets requiring redirects
861 * during ip_rt_redirect_silence, we assume that the host
862 * forgot redirected route and start to send redirects again.
863 *
864 * This algorithm is much cheaper and more intelligent than dumb load limiting
865 * in icmp.c.
866 *
867 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
868 * and "frag. need" (breaks PMTU discovery) in icmp.c.
869 */
870
ip_rt_send_redirect(struct sk_buff * skb)871 void ip_rt_send_redirect(struct sk_buff *skb)
872 {
873 struct rtable *rt = skb_rtable(skb);
874 struct in_device *in_dev;
875 struct inet_peer *peer;
876 struct net *net;
877 int log_martians;
878 int vif;
879
880 rcu_read_lock();
881 in_dev = __in_dev_get_rcu(rt->dst.dev);
882 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
883 rcu_read_unlock();
884 return;
885 }
886 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
887 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
888 rcu_read_unlock();
889
890 net = dev_net(rt->dst.dev);
891 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
892 if (!peer) {
893 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
894 rt_nexthop(rt, ip_hdr(skb)->daddr));
895 return;
896 }
897
898 /* No redirected packets during ip_rt_redirect_silence;
899 * reset the algorithm.
900 */
901 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
902 peer->rate_tokens = 0;
903 peer->n_redirects = 0;
904 }
905
906 /* Too many ignored redirects; do not send anything
907 * set dst.rate_last to the last seen redirected packet.
908 */
909 if (peer->n_redirects >= ip_rt_redirect_number) {
910 peer->rate_last = jiffies;
911 goto out_put_peer;
912 }
913
914 /* Check for load limit; set rate_last to the latest sent
915 * redirect.
916 */
917 if (peer->n_redirects == 0 ||
918 time_after(jiffies,
919 (peer->rate_last +
920 (ip_rt_redirect_load << peer->n_redirects)))) {
921 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
922
923 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
924 peer->rate_last = jiffies;
925 ++peer->n_redirects;
926 #ifdef CONFIG_IP_ROUTE_VERBOSE
927 if (log_martians &&
928 peer->n_redirects == ip_rt_redirect_number)
929 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
930 &ip_hdr(skb)->saddr, inet_iif(skb),
931 &ip_hdr(skb)->daddr, &gw);
932 #endif
933 }
934 out_put_peer:
935 inet_putpeer(peer);
936 }
937
ip_error(struct sk_buff * skb)938 static int ip_error(struct sk_buff *skb)
939 {
940 struct rtable *rt = skb_rtable(skb);
941 struct net_device *dev = skb->dev;
942 struct in_device *in_dev;
943 struct inet_peer *peer;
944 unsigned long now;
945 struct net *net;
946 bool send;
947 int code;
948
949 if (netif_is_l3_master(skb->dev)) {
950 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
951 if (!dev)
952 goto out;
953 }
954
955 in_dev = __in_dev_get_rcu(dev);
956
957 /* IP on this device is disabled. */
958 if (!in_dev)
959 goto out;
960
961 net = dev_net(rt->dst.dev);
962 if (!IN_DEV_FORWARD(in_dev)) {
963 switch (rt->dst.error) {
964 case EHOSTUNREACH:
965 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
966 break;
967
968 case ENETUNREACH:
969 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
970 break;
971 }
972 goto out;
973 }
974
975 switch (rt->dst.error) {
976 case EINVAL:
977 default:
978 goto out;
979 case EHOSTUNREACH:
980 code = ICMP_HOST_UNREACH;
981 break;
982 case ENETUNREACH:
983 code = ICMP_NET_UNREACH;
984 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
985 break;
986 case EACCES:
987 code = ICMP_PKT_FILTERED;
988 break;
989 }
990
991 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
992 l3mdev_master_ifindex(skb->dev), 1);
993
994 send = true;
995 if (peer) {
996 now = jiffies;
997 peer->rate_tokens += now - peer->rate_last;
998 if (peer->rate_tokens > ip_rt_error_burst)
999 peer->rate_tokens = ip_rt_error_burst;
1000 peer->rate_last = now;
1001 if (peer->rate_tokens >= ip_rt_error_cost)
1002 peer->rate_tokens -= ip_rt_error_cost;
1003 else
1004 send = false;
1005 inet_putpeer(peer);
1006 }
1007 if (send)
1008 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1009
1010 out: kfree_skb(skb);
1011 return 0;
1012 }
1013
__ip_rt_update_pmtu(struct rtable * rt,struct flowi4 * fl4,u32 mtu)1014 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1015 {
1016 struct dst_entry *dst = &rt->dst;
1017 struct net *net = dev_net(dst->dev);
1018 struct fib_result res;
1019 bool lock = false;
1020 u32 old_mtu;
1021
1022 if (ip_mtu_locked(dst))
1023 return;
1024
1025 old_mtu = ipv4_mtu(dst);
1026 if (old_mtu < mtu)
1027 return;
1028
1029 if (mtu < ip_rt_min_pmtu) {
1030 lock = true;
1031 mtu = min(old_mtu, ip_rt_min_pmtu);
1032 }
1033
1034 if (rt->rt_pmtu == mtu && !lock &&
1035 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1036 return;
1037
1038 rcu_read_lock();
1039 if (fib_lookup(net, fl4, &res, 0) == 0) {
1040 struct fib_nh_common *nhc;
1041
1042 fib_select_path(net, &res, fl4, NULL);
1043 nhc = FIB_RES_NHC(res);
1044 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1045 jiffies + ip_rt_mtu_expires);
1046 }
1047 rcu_read_unlock();
1048 }
1049
ip_rt_update_pmtu(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb,u32 mtu,bool confirm_neigh)1050 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1051 struct sk_buff *skb, u32 mtu,
1052 bool confirm_neigh)
1053 {
1054 struct rtable *rt = (struct rtable *) dst;
1055 struct flowi4 fl4;
1056
1057 ip_rt_build_flow_key(&fl4, sk, skb);
1058
1059 /* Don't make lookup fail for bridged encapsulations */
1060 if (skb && netif_is_any_bridge_port(skb->dev))
1061 fl4.flowi4_oif = 0;
1062
1063 __ip_rt_update_pmtu(rt, &fl4, mtu);
1064 }
1065
ipv4_update_pmtu(struct sk_buff * skb,struct net * net,u32 mtu,int oif,u8 protocol)1066 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1067 int oif, u8 protocol)
1068 {
1069 const struct iphdr *iph = (const struct iphdr *)skb->data;
1070 struct flowi4 fl4;
1071 struct rtable *rt;
1072 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1073
1074 __build_flow_key(net, &fl4, NULL, iph, oif,
1075 RT_TOS(iph->tos), protocol, mark, 0);
1076 rt = __ip_route_output_key(net, &fl4);
1077 if (!IS_ERR(rt)) {
1078 __ip_rt_update_pmtu(rt, &fl4, mtu);
1079 ip_rt_put(rt);
1080 }
1081 }
1082 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1083
__ipv4_sk_update_pmtu(struct sk_buff * skb,struct sock * sk,u32 mtu)1084 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1085 {
1086 const struct iphdr *iph = (const struct iphdr *)skb->data;
1087 struct flowi4 fl4;
1088 struct rtable *rt;
1089
1090 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1091
1092 if (!fl4.flowi4_mark)
1093 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1094
1095 rt = __ip_route_output_key(sock_net(sk), &fl4);
1096 if (!IS_ERR(rt)) {
1097 __ip_rt_update_pmtu(rt, &fl4, mtu);
1098 ip_rt_put(rt);
1099 }
1100 }
1101
ipv4_sk_update_pmtu(struct sk_buff * skb,struct sock * sk,u32 mtu)1102 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1103 {
1104 const struct iphdr *iph = (const struct iphdr *)skb->data;
1105 struct flowi4 fl4;
1106 struct rtable *rt;
1107 struct dst_entry *odst = NULL;
1108 bool new = false;
1109 struct net *net = sock_net(sk);
1110
1111 bh_lock_sock(sk);
1112
1113 if (!ip_sk_accept_pmtu(sk))
1114 goto out;
1115
1116 odst = sk_dst_get(sk);
1117
1118 if (sock_owned_by_user(sk) || !odst) {
1119 __ipv4_sk_update_pmtu(skb, sk, mtu);
1120 goto out;
1121 }
1122
1123 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1124
1125 rt = (struct rtable *)odst;
1126 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1127 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1128 if (IS_ERR(rt))
1129 goto out;
1130
1131 new = true;
1132 }
1133
1134 __ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu);
1135
1136 if (!dst_check(&rt->dst, 0)) {
1137 if (new)
1138 dst_release(&rt->dst);
1139
1140 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1141 if (IS_ERR(rt))
1142 goto out;
1143
1144 new = true;
1145 }
1146
1147 if (new)
1148 sk_dst_set(sk, &rt->dst);
1149
1150 out:
1151 bh_unlock_sock(sk);
1152 dst_release(odst);
1153 }
1154 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1155
ipv4_redirect(struct sk_buff * skb,struct net * net,int oif,u8 protocol)1156 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1157 int oif, u8 protocol)
1158 {
1159 const struct iphdr *iph = (const struct iphdr *)skb->data;
1160 struct flowi4 fl4;
1161 struct rtable *rt;
1162
1163 __build_flow_key(net, &fl4, NULL, iph, oif,
1164 RT_TOS(iph->tos), protocol, 0, 0);
1165 rt = __ip_route_output_key(net, &fl4);
1166 if (!IS_ERR(rt)) {
1167 __ip_do_redirect(rt, skb, &fl4, false);
1168 ip_rt_put(rt);
1169 }
1170 }
1171 EXPORT_SYMBOL_GPL(ipv4_redirect);
1172
ipv4_sk_redirect(struct sk_buff * skb,struct sock * sk)1173 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1174 {
1175 const struct iphdr *iph = (const struct iphdr *)skb->data;
1176 struct flowi4 fl4;
1177 struct rtable *rt;
1178 struct net *net = sock_net(sk);
1179
1180 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1181 rt = __ip_route_output_key(net, &fl4);
1182 if (!IS_ERR(rt)) {
1183 __ip_do_redirect(rt, skb, &fl4, false);
1184 ip_rt_put(rt);
1185 }
1186 }
1187 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1188
ipv4_dst_check(struct dst_entry * dst,u32 cookie)1189 INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1190 u32 cookie)
1191 {
1192 struct rtable *rt = (struct rtable *) dst;
1193
1194 /* All IPV4 dsts are created with ->obsolete set to the value
1195 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1196 * into this function always.
1197 *
1198 * When a PMTU/redirect information update invalidates a route,
1199 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1200 * DST_OBSOLETE_DEAD.
1201 */
1202 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1203 return NULL;
1204 return dst;
1205 }
1206 EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1207
ipv4_send_dest_unreach(struct sk_buff * skb)1208 static void ipv4_send_dest_unreach(struct sk_buff *skb)
1209 {
1210 struct ip_options opt;
1211 int res;
1212
1213 /* Recompile ip options since IPCB may not be valid anymore.
1214 * Also check we have a reasonable ipv4 header.
1215 */
1216 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1217 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1218 return;
1219
1220 memset(&opt, 0, sizeof(opt));
1221 if (ip_hdr(skb)->ihl > 5) {
1222 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1223 return;
1224 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1225
1226 rcu_read_lock();
1227 res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL);
1228 rcu_read_unlock();
1229
1230 if (res)
1231 return;
1232 }
1233 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1234 }
1235
ipv4_link_failure(struct sk_buff * skb)1236 static void ipv4_link_failure(struct sk_buff *skb)
1237 {
1238 struct rtable *rt;
1239
1240 ipv4_send_dest_unreach(skb);
1241
1242 rt = skb_rtable(skb);
1243 if (rt)
1244 dst_set_expires(&rt->dst, 0);
1245 }
1246
ip_rt_bug(struct net * net,struct sock * sk,struct sk_buff * skb)1247 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1248 {
1249 pr_debug("%s: %pI4 -> %pI4, %s\n",
1250 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1251 skb->dev ? skb->dev->name : "?");
1252 kfree_skb(skb);
1253 WARN_ON(1);
1254 return 0;
1255 }
1256
1257 /*
1258 * We do not cache source address of outgoing interface,
1259 * because it is used only by IP RR, TS and SRR options,
1260 * so that it out of fast path.
1261 *
1262 * BTW remember: "addr" is allowed to be not aligned
1263 * in IP options!
1264 */
1265
ip_rt_get_source(u8 * addr,struct sk_buff * skb,struct rtable * rt)1266 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1267 {
1268 __be32 src;
1269
1270 if (rt_is_output_route(rt))
1271 src = ip_hdr(skb)->saddr;
1272 else {
1273 struct fib_result res;
1274 struct iphdr *iph = ip_hdr(skb);
1275 struct flowi4 fl4 = {
1276 .daddr = iph->daddr,
1277 .saddr = iph->saddr,
1278 .flowi4_tos = RT_TOS(iph->tos),
1279 .flowi4_oif = rt->dst.dev->ifindex,
1280 .flowi4_iif = skb->dev->ifindex,
1281 .flowi4_mark = skb->mark,
1282 };
1283
1284 rcu_read_lock();
1285 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1286 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1287 else
1288 src = inet_select_addr(rt->dst.dev,
1289 rt_nexthop(rt, iph->daddr),
1290 RT_SCOPE_UNIVERSE);
1291 rcu_read_unlock();
1292 }
1293 memcpy(addr, &src, 4);
1294 }
1295
1296 #ifdef CONFIG_IP_ROUTE_CLASSID
set_class_tag(struct rtable * rt,u32 tag)1297 static void set_class_tag(struct rtable *rt, u32 tag)
1298 {
1299 if (!(rt->dst.tclassid & 0xFFFF))
1300 rt->dst.tclassid |= tag & 0xFFFF;
1301 if (!(rt->dst.tclassid & 0xFFFF0000))
1302 rt->dst.tclassid |= tag & 0xFFFF0000;
1303 }
1304 #endif
1305
ipv4_default_advmss(const struct dst_entry * dst)1306 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1307 {
1308 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1309 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1310 ip_rt_min_advmss);
1311
1312 return min(advmss, IPV4_MAX_PMTU - header_size);
1313 }
1314
ipv4_mtu(const struct dst_entry * dst)1315 INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1316 {
1317 return ip_dst_mtu_maybe_forward(dst, false);
1318 }
1319 EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1320
ip_del_fnhe(struct fib_nh_common * nhc,__be32 daddr)1321 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1322 {
1323 struct fnhe_hash_bucket *hash;
1324 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1325 u32 hval = fnhe_hashfun(daddr);
1326
1327 spin_lock_bh(&fnhe_lock);
1328
1329 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1330 lockdep_is_held(&fnhe_lock));
1331 hash += hval;
1332
1333 fnhe_p = &hash->chain;
1334 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1335 while (fnhe) {
1336 if (fnhe->fnhe_daddr == daddr) {
1337 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1338 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1339 /* set fnhe_daddr to 0 to ensure it won't bind with
1340 * new dsts in rt_bind_exception().
1341 */
1342 fnhe->fnhe_daddr = 0;
1343 fnhe_flush_routes(fnhe);
1344 kfree_rcu(fnhe, rcu);
1345 break;
1346 }
1347 fnhe_p = &fnhe->fnhe_next;
1348 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1349 lockdep_is_held(&fnhe_lock));
1350 }
1351
1352 spin_unlock_bh(&fnhe_lock);
1353 }
1354
find_exception(struct fib_nh_common * nhc,__be32 daddr)1355 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1356 __be32 daddr)
1357 {
1358 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1359 struct fib_nh_exception *fnhe;
1360 u32 hval;
1361
1362 if (!hash)
1363 return NULL;
1364
1365 hval = fnhe_hashfun(daddr);
1366
1367 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1368 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1369 if (fnhe->fnhe_daddr == daddr) {
1370 if (fnhe->fnhe_expires &&
1371 time_after(jiffies, fnhe->fnhe_expires)) {
1372 ip_del_fnhe(nhc, daddr);
1373 break;
1374 }
1375 return fnhe;
1376 }
1377 }
1378 return NULL;
1379 }
1380
1381 /* MTU selection:
1382 * 1. mtu on route is locked - use it
1383 * 2. mtu from nexthop exception
1384 * 3. mtu from egress device
1385 */
1386
ip_mtu_from_fib_result(struct fib_result * res,__be32 daddr)1387 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1388 {
1389 struct fib_nh_common *nhc = res->nhc;
1390 struct net_device *dev = nhc->nhc_dev;
1391 struct fib_info *fi = res->fi;
1392 u32 mtu = 0;
1393
1394 if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu ||
1395 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1396 mtu = fi->fib_mtu;
1397
1398 if (likely(!mtu)) {
1399 struct fib_nh_exception *fnhe;
1400
1401 fnhe = find_exception(nhc, daddr);
1402 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1403 mtu = fnhe->fnhe_pmtu;
1404 }
1405
1406 if (likely(!mtu))
1407 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1408
1409 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1410 }
1411
rt_bind_exception(struct rtable * rt,struct fib_nh_exception * fnhe,__be32 daddr,const bool do_cache)1412 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1413 __be32 daddr, const bool do_cache)
1414 {
1415 bool ret = false;
1416
1417 spin_lock_bh(&fnhe_lock);
1418
1419 if (daddr == fnhe->fnhe_daddr) {
1420 struct rtable __rcu **porig;
1421 struct rtable *orig;
1422 int genid = fnhe_genid(dev_net(rt->dst.dev));
1423
1424 if (rt_is_input_route(rt))
1425 porig = &fnhe->fnhe_rth_input;
1426 else
1427 porig = &fnhe->fnhe_rth_output;
1428 orig = rcu_dereference(*porig);
1429
1430 if (fnhe->fnhe_genid != genid) {
1431 fnhe->fnhe_genid = genid;
1432 fnhe->fnhe_gw = 0;
1433 fnhe->fnhe_pmtu = 0;
1434 fnhe->fnhe_expires = 0;
1435 fnhe->fnhe_mtu_locked = false;
1436 fnhe_flush_routes(fnhe);
1437 orig = NULL;
1438 }
1439 fill_route_from_fnhe(rt, fnhe);
1440 if (!rt->rt_gw4) {
1441 rt->rt_gw4 = daddr;
1442 rt->rt_gw_family = AF_INET;
1443 }
1444
1445 if (do_cache) {
1446 dst_hold(&rt->dst);
1447 rcu_assign_pointer(*porig, rt);
1448 if (orig) {
1449 dst_dev_put(&orig->dst);
1450 dst_release(&orig->dst);
1451 }
1452 ret = true;
1453 }
1454
1455 fnhe->fnhe_stamp = jiffies;
1456 }
1457 spin_unlock_bh(&fnhe_lock);
1458
1459 return ret;
1460 }
1461
rt_cache_route(struct fib_nh_common * nhc,struct rtable * rt)1462 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1463 {
1464 struct rtable *orig, *prev, **p;
1465 bool ret = true;
1466
1467 if (rt_is_input_route(rt)) {
1468 p = (struct rtable **)&nhc->nhc_rth_input;
1469 } else {
1470 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1471 }
1472 orig = *p;
1473
1474 /* hold dst before doing cmpxchg() to avoid race condition
1475 * on this dst
1476 */
1477 dst_hold(&rt->dst);
1478 prev = cmpxchg(p, orig, rt);
1479 if (prev == orig) {
1480 if (orig) {
1481 rt_add_uncached_list(orig);
1482 dst_release(&orig->dst);
1483 }
1484 } else {
1485 dst_release(&rt->dst);
1486 ret = false;
1487 }
1488
1489 return ret;
1490 }
1491
1492 struct uncached_list {
1493 spinlock_t lock;
1494 struct list_head head;
1495 };
1496
1497 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1498
rt_add_uncached_list(struct rtable * rt)1499 void rt_add_uncached_list(struct rtable *rt)
1500 {
1501 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1502
1503 rt->rt_uncached_list = ul;
1504
1505 spin_lock_bh(&ul->lock);
1506 list_add_tail(&rt->rt_uncached, &ul->head);
1507 spin_unlock_bh(&ul->lock);
1508 }
1509
rt_del_uncached_list(struct rtable * rt)1510 void rt_del_uncached_list(struct rtable *rt)
1511 {
1512 if (!list_empty(&rt->rt_uncached)) {
1513 struct uncached_list *ul = rt->rt_uncached_list;
1514
1515 spin_lock_bh(&ul->lock);
1516 list_del(&rt->rt_uncached);
1517 spin_unlock_bh(&ul->lock);
1518 }
1519 }
1520
ipv4_dst_destroy(struct dst_entry * dst)1521 static void ipv4_dst_destroy(struct dst_entry *dst)
1522 {
1523 struct rtable *rt = (struct rtable *)dst;
1524
1525 ip_dst_metrics_put(dst);
1526 rt_del_uncached_list(rt);
1527 }
1528
rt_flush_dev(struct net_device * dev)1529 void rt_flush_dev(struct net_device *dev)
1530 {
1531 struct rtable *rt;
1532 int cpu;
1533
1534 for_each_possible_cpu(cpu) {
1535 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1536
1537 spin_lock_bh(&ul->lock);
1538 list_for_each_entry(rt, &ul->head, rt_uncached) {
1539 if (rt->dst.dev != dev)
1540 continue;
1541 rt->dst.dev = blackhole_netdev;
1542 dev_hold(rt->dst.dev);
1543 dev_put(dev);
1544 }
1545 spin_unlock_bh(&ul->lock);
1546 }
1547 }
1548
rt_cache_valid(const struct rtable * rt)1549 static bool rt_cache_valid(const struct rtable *rt)
1550 {
1551 return rt &&
1552 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1553 !rt_is_expired(rt);
1554 }
1555
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)1556 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1557 const struct fib_result *res,
1558 struct fib_nh_exception *fnhe,
1559 struct fib_info *fi, u16 type, u32 itag,
1560 const bool do_cache)
1561 {
1562 bool cached = false;
1563
1564 if (fi) {
1565 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1566
1567 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1568 rt->rt_uses_gateway = 1;
1569 rt->rt_gw_family = nhc->nhc_gw_family;
1570 /* only INET and INET6 are supported */
1571 if (likely(nhc->nhc_gw_family == AF_INET))
1572 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1573 else
1574 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1575 }
1576
1577 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1578
1579 #ifdef CONFIG_IP_ROUTE_CLASSID
1580 if (nhc->nhc_family == AF_INET) {
1581 struct fib_nh *nh;
1582
1583 nh = container_of(nhc, struct fib_nh, nh_common);
1584 rt->dst.tclassid = nh->nh_tclassid;
1585 }
1586 #endif
1587 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1588 if (unlikely(fnhe))
1589 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1590 else if (do_cache)
1591 cached = rt_cache_route(nhc, rt);
1592 if (unlikely(!cached)) {
1593 /* Routes we intend to cache in nexthop exception or
1594 * FIB nexthop have the DST_NOCACHE bit clear.
1595 * However, if we are unsuccessful at storing this
1596 * route into the cache we really need to set it.
1597 */
1598 if (!rt->rt_gw4) {
1599 rt->rt_gw_family = AF_INET;
1600 rt->rt_gw4 = daddr;
1601 }
1602 rt_add_uncached_list(rt);
1603 }
1604 } else
1605 rt_add_uncached_list(rt);
1606
1607 #ifdef CONFIG_IP_ROUTE_CLASSID
1608 #ifdef CONFIG_IP_MULTIPLE_TABLES
1609 set_class_tag(rt, res->tclassid);
1610 #endif
1611 set_class_tag(rt, itag);
1612 #endif
1613 }
1614
rt_dst_alloc(struct net_device * dev,unsigned int flags,u16 type,bool nopolicy,bool noxfrm)1615 struct rtable *rt_dst_alloc(struct net_device *dev,
1616 unsigned int flags, u16 type,
1617 bool nopolicy, bool noxfrm)
1618 {
1619 struct rtable *rt;
1620
1621 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1622 (nopolicy ? DST_NOPOLICY : 0) |
1623 (noxfrm ? DST_NOXFRM : 0));
1624
1625 if (rt) {
1626 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1627 rt->rt_flags = flags;
1628 rt->rt_type = type;
1629 rt->rt_is_input = 0;
1630 rt->rt_iif = 0;
1631 rt->rt_pmtu = 0;
1632 rt->rt_mtu_locked = 0;
1633 rt->rt_uses_gateway = 0;
1634 rt->rt_gw_family = 0;
1635 rt->rt_gw4 = 0;
1636 INIT_LIST_HEAD(&rt->rt_uncached);
1637
1638 rt->dst.output = ip_output;
1639 if (flags & RTCF_LOCAL)
1640 rt->dst.input = ip_local_deliver;
1641 }
1642
1643 return rt;
1644 }
1645 EXPORT_SYMBOL(rt_dst_alloc);
1646
rt_dst_clone(struct net_device * dev,struct rtable * rt)1647 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1648 {
1649 struct rtable *new_rt;
1650
1651 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1652 rt->dst.flags);
1653
1654 if (new_rt) {
1655 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1656 new_rt->rt_flags = rt->rt_flags;
1657 new_rt->rt_type = rt->rt_type;
1658 new_rt->rt_is_input = rt->rt_is_input;
1659 new_rt->rt_iif = rt->rt_iif;
1660 new_rt->rt_pmtu = rt->rt_pmtu;
1661 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1662 new_rt->rt_gw_family = rt->rt_gw_family;
1663 if (rt->rt_gw_family == AF_INET)
1664 new_rt->rt_gw4 = rt->rt_gw4;
1665 else if (rt->rt_gw_family == AF_INET6)
1666 new_rt->rt_gw6 = rt->rt_gw6;
1667 INIT_LIST_HEAD(&new_rt->rt_uncached);
1668
1669 new_rt->dst.input = rt->dst.input;
1670 new_rt->dst.output = rt->dst.output;
1671 new_rt->dst.error = rt->dst.error;
1672 new_rt->dst.lastuse = jiffies;
1673 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1674 }
1675 return new_rt;
1676 }
1677 EXPORT_SYMBOL(rt_dst_clone);
1678
1679 /* 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)1680 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1681 u8 tos, struct net_device *dev,
1682 struct in_device *in_dev, u32 *itag)
1683 {
1684 int err;
1685
1686 /* Primary sanity checks. */
1687 if (!in_dev)
1688 return -EINVAL;
1689
1690 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1691 skb->protocol != htons(ETH_P_IP))
1692 return -EINVAL;
1693
1694 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1695 return -EINVAL;
1696
1697 if (ipv4_is_zeronet(saddr)) {
1698 if (!ipv4_is_local_multicast(daddr) &&
1699 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1700 return -EINVAL;
1701 } else {
1702 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1703 in_dev, itag);
1704 if (err < 0)
1705 return err;
1706 }
1707 return 0;
1708 }
1709
1710 /* 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)1711 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1712 u8 tos, struct net_device *dev, int our)
1713 {
1714 struct in_device *in_dev = __in_dev_get_rcu(dev);
1715 unsigned int flags = RTCF_MULTICAST;
1716 struct rtable *rth;
1717 u32 itag = 0;
1718 int err;
1719
1720 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1721 if (err)
1722 return err;
1723
1724 if (our)
1725 flags |= RTCF_LOCAL;
1726
1727 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1728 IN_DEV_ORCONF(in_dev, NOPOLICY), false);
1729 if (!rth)
1730 return -ENOBUFS;
1731
1732 #ifdef CONFIG_IP_ROUTE_CLASSID
1733 rth->dst.tclassid = itag;
1734 #endif
1735 rth->dst.output = ip_rt_bug;
1736 rth->rt_is_input= 1;
1737
1738 #ifdef CONFIG_IP_MROUTE
1739 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1740 rth->dst.input = ip_mr_input;
1741 #endif
1742 RT_CACHE_STAT_INC(in_slow_mc);
1743
1744 skb_dst_set(skb, &rth->dst);
1745 return 0;
1746 }
1747
1748
ip_handle_martian_source(struct net_device * dev,struct in_device * in_dev,struct sk_buff * skb,__be32 daddr,__be32 saddr)1749 static void ip_handle_martian_source(struct net_device *dev,
1750 struct in_device *in_dev,
1751 struct sk_buff *skb,
1752 __be32 daddr,
1753 __be32 saddr)
1754 {
1755 RT_CACHE_STAT_INC(in_martian_src);
1756 #ifdef CONFIG_IP_ROUTE_VERBOSE
1757 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1758 /*
1759 * RFC1812 recommendation, if source is martian,
1760 * the only hint is MAC header.
1761 */
1762 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1763 &daddr, &saddr, dev->name);
1764 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1765 print_hex_dump(KERN_WARNING, "ll header: ",
1766 DUMP_PREFIX_OFFSET, 16, 1,
1767 skb_mac_header(skb),
1768 dev->hard_header_len, false);
1769 }
1770 }
1771 #endif
1772 }
1773
1774 /* 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)1775 static int __mkroute_input(struct sk_buff *skb,
1776 const struct fib_result *res,
1777 struct in_device *in_dev,
1778 __be32 daddr, __be32 saddr, u32 tos)
1779 {
1780 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1781 struct net_device *dev = nhc->nhc_dev;
1782 struct fib_nh_exception *fnhe;
1783 struct rtable *rth;
1784 int err;
1785 struct in_device *out_dev;
1786 bool do_cache;
1787 u32 itag = 0;
1788
1789 /* get a working reference to the output device */
1790 out_dev = __in_dev_get_rcu(dev);
1791 if (!out_dev) {
1792 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1793 return -EINVAL;
1794 }
1795
1796 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1797 in_dev->dev, in_dev, &itag);
1798 if (err < 0) {
1799 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1800 saddr);
1801
1802 goto cleanup;
1803 }
1804
1805 do_cache = res->fi && !itag;
1806 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1807 skb->protocol == htons(ETH_P_IP)) {
1808 __be32 gw;
1809
1810 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1811 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1812 inet_addr_onlink(out_dev, saddr, gw))
1813 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1814 }
1815
1816 if (skb->protocol != htons(ETH_P_IP)) {
1817 /* Not IP (i.e. ARP). Do not create route, if it is
1818 * invalid for proxy arp. DNAT routes are always valid.
1819 *
1820 * Proxy arp feature have been extended to allow, ARP
1821 * replies back to the same interface, to support
1822 * Private VLAN switch technologies. See arp.c.
1823 */
1824 if (out_dev == in_dev &&
1825 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1826 err = -EINVAL;
1827 goto cleanup;
1828 }
1829 }
1830
1831 fnhe = find_exception(nhc, daddr);
1832 if (do_cache) {
1833 if (fnhe)
1834 rth = rcu_dereference(fnhe->fnhe_rth_input);
1835 else
1836 rth = rcu_dereference(nhc->nhc_rth_input);
1837 if (rt_cache_valid(rth)) {
1838 skb_dst_set_noref(skb, &rth->dst);
1839 goto out;
1840 }
1841 }
1842
1843 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1844 IN_DEV_ORCONF(in_dev, NOPOLICY),
1845 IN_DEV_ORCONF(out_dev, NOXFRM));
1846 if (!rth) {
1847 err = -ENOBUFS;
1848 goto cleanup;
1849 }
1850
1851 rth->rt_is_input = 1;
1852 RT_CACHE_STAT_INC(in_slow_tot);
1853
1854 rth->dst.input = ip_forward;
1855
1856 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1857 do_cache);
1858 lwtunnel_set_redirect(&rth->dst);
1859 skb_dst_set(skb, &rth->dst);
1860 out:
1861 err = 0;
1862 cleanup:
1863 return err;
1864 }
1865
1866 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1867 /* To make ICMP packets follow the right flow, the multipath hash is
1868 * calculated from the inner IP addresses.
1869 */
ip_multipath_l3_keys(const struct sk_buff * skb,struct flow_keys * hash_keys)1870 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1871 struct flow_keys *hash_keys)
1872 {
1873 const struct iphdr *outer_iph = ip_hdr(skb);
1874 const struct iphdr *key_iph = outer_iph;
1875 const struct iphdr *inner_iph;
1876 const struct icmphdr *icmph;
1877 struct iphdr _inner_iph;
1878 struct icmphdr _icmph;
1879
1880 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1881 goto out;
1882
1883 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1884 goto out;
1885
1886 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1887 &_icmph);
1888 if (!icmph)
1889 goto out;
1890
1891 if (!icmp_is_err(icmph->type))
1892 goto out;
1893
1894 inner_iph = skb_header_pointer(skb,
1895 outer_iph->ihl * 4 + sizeof(_icmph),
1896 sizeof(_inner_iph), &_inner_iph);
1897 if (!inner_iph)
1898 goto out;
1899
1900 key_iph = inner_iph;
1901 out:
1902 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1903 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1904 }
1905
fib_multipath_custom_hash_outer(const struct net * net,const struct sk_buff * skb,bool * p_has_inner)1906 static u32 fib_multipath_custom_hash_outer(const struct net *net,
1907 const struct sk_buff *skb,
1908 bool *p_has_inner)
1909 {
1910 u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
1911 struct flow_keys keys, hash_keys;
1912
1913 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1914 return 0;
1915
1916 memset(&hash_keys, 0, sizeof(hash_keys));
1917 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1918
1919 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1920 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1921 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1922 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1923 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1924 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1925 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1926 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1927 hash_keys.ports.src = keys.ports.src;
1928 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1929 hash_keys.ports.dst = keys.ports.dst;
1930
1931 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1932 return flow_hash_from_keys(&hash_keys);
1933 }
1934
fib_multipath_custom_hash_inner(const struct net * net,const struct sk_buff * skb,bool has_inner)1935 static u32 fib_multipath_custom_hash_inner(const struct net *net,
1936 const struct sk_buff *skb,
1937 bool has_inner)
1938 {
1939 u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
1940 struct flow_keys keys, hash_keys;
1941
1942 /* We assume the packet carries an encapsulation, but if none was
1943 * encountered during dissection of the outer flow, then there is no
1944 * point in calling the flow dissector again.
1945 */
1946 if (!has_inner)
1947 return 0;
1948
1949 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1950 return 0;
1951
1952 memset(&hash_keys, 0, sizeof(hash_keys));
1953 skb_flow_dissect_flow_keys(skb, &keys, 0);
1954
1955 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1956 return 0;
1957
1958 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1959 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1960 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1961 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1962 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1963 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1964 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1965 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1966 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1967 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1968 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1969 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1970 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1971 hash_keys.tags.flow_label = keys.tags.flow_label;
1972 }
1973
1974 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
1975 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1976 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
1977 hash_keys.ports.src = keys.ports.src;
1978 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
1979 hash_keys.ports.dst = keys.ports.dst;
1980
1981 return flow_hash_from_keys(&hash_keys);
1982 }
1983
fib_multipath_custom_hash_skb(const struct net * net,const struct sk_buff * skb)1984 static u32 fib_multipath_custom_hash_skb(const struct net *net,
1985 const struct sk_buff *skb)
1986 {
1987 u32 mhash, mhash_inner;
1988 bool has_inner = true;
1989
1990 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
1991 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
1992
1993 return jhash_2words(mhash, mhash_inner, 0);
1994 }
1995
fib_multipath_custom_hash_fl4(const struct net * net,const struct flowi4 * fl4)1996 static u32 fib_multipath_custom_hash_fl4(const struct net *net,
1997 const struct flowi4 *fl4)
1998 {
1999 u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
2000 struct flow_keys hash_keys;
2001
2002 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
2003 return 0;
2004
2005 memset(&hash_keys, 0, sizeof(hash_keys));
2006 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2007 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2008 hash_keys.addrs.v4addrs.src = fl4->saddr;
2009 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2010 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2011 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2012 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2013 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2014 hash_keys.ports.src = fl4->fl4_sport;
2015 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2016 hash_keys.ports.dst = fl4->fl4_dport;
2017
2018 return flow_hash_from_keys(&hash_keys);
2019 }
2020
2021 /* 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)2022 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2023 const struct sk_buff *skb, struct flow_keys *flkeys)
2024 {
2025 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2026 struct flow_keys hash_keys;
2027 u32 mhash = 0;
2028
2029 switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
2030 case 0:
2031 memset(&hash_keys, 0, sizeof(hash_keys));
2032 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2033 if (skb) {
2034 ip_multipath_l3_keys(skb, &hash_keys);
2035 } else {
2036 hash_keys.addrs.v4addrs.src = fl4->saddr;
2037 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2038 }
2039 mhash = flow_hash_from_keys(&hash_keys);
2040 break;
2041 case 1:
2042 /* skb is currently provided only when forwarding */
2043 if (skb) {
2044 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2045 struct flow_keys keys;
2046
2047 /* short-circuit if we already have L4 hash present */
2048 if (skb->l4_hash)
2049 return skb_get_hash_raw(skb) >> 1;
2050
2051 memset(&hash_keys, 0, sizeof(hash_keys));
2052
2053 if (!flkeys) {
2054 skb_flow_dissect_flow_keys(skb, &keys, flag);
2055 flkeys = &keys;
2056 }
2057
2058 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2059 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2060 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2061 hash_keys.ports.src = flkeys->ports.src;
2062 hash_keys.ports.dst = flkeys->ports.dst;
2063 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2064 } else {
2065 memset(&hash_keys, 0, sizeof(hash_keys));
2066 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2067 hash_keys.addrs.v4addrs.src = fl4->saddr;
2068 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2069 hash_keys.ports.src = fl4->fl4_sport;
2070 hash_keys.ports.dst = fl4->fl4_dport;
2071 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2072 }
2073 mhash = flow_hash_from_keys(&hash_keys);
2074 break;
2075 case 2:
2076 memset(&hash_keys, 0, sizeof(hash_keys));
2077 /* skb is currently provided only when forwarding */
2078 if (skb) {
2079 struct flow_keys keys;
2080
2081 skb_flow_dissect_flow_keys(skb, &keys, 0);
2082 /* Inner can be v4 or v6 */
2083 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2084 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2085 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2086 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2087 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2088 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2089 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2090 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2091 hash_keys.tags.flow_label = keys.tags.flow_label;
2092 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2093 } else {
2094 /* Same as case 0 */
2095 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2096 ip_multipath_l3_keys(skb, &hash_keys);
2097 }
2098 } else {
2099 /* Same as case 0 */
2100 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2101 hash_keys.addrs.v4addrs.src = fl4->saddr;
2102 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2103 }
2104 mhash = flow_hash_from_keys(&hash_keys);
2105 break;
2106 case 3:
2107 if (skb)
2108 mhash = fib_multipath_custom_hash_skb(net, skb);
2109 else
2110 mhash = fib_multipath_custom_hash_fl4(net, fl4);
2111 break;
2112 }
2113
2114 if (multipath_hash)
2115 mhash = jhash_2words(mhash, multipath_hash, 0);
2116
2117 return mhash >> 1;
2118 }
2119 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
2120
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)2121 static int ip_mkroute_input(struct sk_buff *skb,
2122 struct fib_result *res,
2123 struct in_device *in_dev,
2124 __be32 daddr, __be32 saddr, u32 tos,
2125 struct flow_keys *hkeys)
2126 {
2127 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2128 if (res->fi && fib_info_num_path(res->fi) > 1) {
2129 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2130
2131 fib_select_multipath(res, h);
2132 }
2133 #endif
2134
2135 /* create a routing cache entry */
2136 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2137 }
2138
2139 /* Implements all the saddr-related checks as ip_route_input_slow(),
2140 * assuming daddr is valid and the destination is not a local broadcast one.
2141 * Uses the provided hint instead of performing a route lookup.
2142 */
ip_route_use_hint(struct sk_buff * skb,__be32 daddr,__be32 saddr,u8 tos,struct net_device * dev,const struct sk_buff * hint)2143 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2144 u8 tos, struct net_device *dev,
2145 const struct sk_buff *hint)
2146 {
2147 struct in_device *in_dev = __in_dev_get_rcu(dev);
2148 struct rtable *rt = skb_rtable(hint);
2149 struct net *net = dev_net(dev);
2150 int err = -EINVAL;
2151 u32 tag = 0;
2152
2153 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2154 goto martian_source;
2155
2156 if (ipv4_is_zeronet(saddr))
2157 goto martian_source;
2158
2159 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2160 goto martian_source;
2161
2162 if (rt->rt_type != RTN_LOCAL)
2163 goto skip_validate_source;
2164
2165 tos &= IPTOS_RT_MASK;
2166 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2167 if (err < 0)
2168 goto martian_source;
2169
2170 skip_validate_source:
2171 skb_dst_copy(skb, hint);
2172 return 0;
2173
2174 martian_source:
2175 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2176 return err;
2177 }
2178
2179 /* get device for dst_alloc with local routes */
ip_rt_get_dev(struct net * net,const struct fib_result * res)2180 static struct net_device *ip_rt_get_dev(struct net *net,
2181 const struct fib_result *res)
2182 {
2183 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2184 struct net_device *dev = NULL;
2185
2186 if (nhc)
2187 dev = l3mdev_master_dev_rcu(nhc->nhc_dev);
2188
2189 return dev ? : net->loopback_dev;
2190 }
2191
2192 /*
2193 * NOTE. We drop all the packets that has local source
2194 * addresses, because every properly looped back packet
2195 * must have correct destination already attached by output routine.
2196 * Changes in the enforced policies must be applied also to
2197 * ip_route_use_hint().
2198 *
2199 * Such approach solves two big problems:
2200 * 1. Not simplex devices are handled properly.
2201 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2202 * called with rcu_read_lock()
2203 */
2204
ip_route_input_slow(struct sk_buff * skb,__be32 daddr,__be32 saddr,u8 tos,struct net_device * dev,struct fib_result * res)2205 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2206 u8 tos, struct net_device *dev,
2207 struct fib_result *res)
2208 {
2209 struct in_device *in_dev = __in_dev_get_rcu(dev);
2210 struct flow_keys *flkeys = NULL, _flkeys;
2211 struct net *net = dev_net(dev);
2212 struct ip_tunnel_info *tun_info;
2213 int err = -EINVAL;
2214 unsigned int flags = 0;
2215 u32 itag = 0;
2216 struct rtable *rth;
2217 struct flowi4 fl4;
2218 bool do_cache = true;
2219
2220 /* IP on this device is disabled. */
2221
2222 if (!in_dev)
2223 goto out;
2224
2225 /* Check for the most weird martians, which can be not detected
2226 * by fib_lookup.
2227 */
2228
2229 tun_info = skb_tunnel_info(skb);
2230 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2231 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2232 else
2233 fl4.flowi4_tun_key.tun_id = 0;
2234 skb_dst_drop(skb);
2235
2236 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2237 goto martian_source;
2238
2239 res->fi = NULL;
2240 res->table = NULL;
2241 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2242 goto brd_input;
2243
2244 /* Accept zero addresses only to limited broadcast;
2245 * I even do not know to fix it or not. Waiting for complains :-)
2246 */
2247 if (ipv4_is_zeronet(saddr))
2248 goto martian_source;
2249
2250 if (ipv4_is_zeronet(daddr))
2251 goto martian_destination;
2252
2253 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2254 * and call it once if daddr or/and saddr are loopback addresses
2255 */
2256 if (ipv4_is_loopback(daddr)) {
2257 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2258 goto martian_destination;
2259 } else if (ipv4_is_loopback(saddr)) {
2260 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2261 goto martian_source;
2262 }
2263
2264 /*
2265 * Now we are ready to route packet.
2266 */
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(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 do_cache &= res->fi && !itag;
2337 if (do_cache) {
2338 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2339
2340 rth = rcu_dereference(nhc->nhc_rth_input);
2341 if (rt_cache_valid(rth)) {
2342 skb_dst_set_noref(skb, &rth->dst);
2343 err = 0;
2344 goto out;
2345 }
2346 }
2347
2348 rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2349 flags | RTCF_LOCAL, res->type,
2350 IN_DEV_ORCONF(in_dev, NOPOLICY), false);
2351 if (!rth)
2352 goto e_nobufs;
2353
2354 rth->dst.output= ip_rt_bug;
2355 #ifdef CONFIG_IP_ROUTE_CLASSID
2356 rth->dst.tclassid = itag;
2357 #endif
2358 rth->rt_is_input = 1;
2359
2360 RT_CACHE_STAT_INC(in_slow_tot);
2361 if (res->type == RTN_UNREACHABLE) {
2362 rth->dst.input= ip_error;
2363 rth->dst.error= -err;
2364 rth->rt_flags &= ~RTCF_LOCAL;
2365 }
2366
2367 if (do_cache) {
2368 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2369
2370 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2371 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2372 WARN_ON(rth->dst.input == lwtunnel_input);
2373 rth->dst.lwtstate->orig_input = rth->dst.input;
2374 rth->dst.input = lwtunnel_input;
2375 }
2376
2377 if (unlikely(!rt_cache_route(nhc, rth)))
2378 rt_add_uncached_list(rth);
2379 }
2380 skb_dst_set(skb, &rth->dst);
2381 err = 0;
2382 goto out;
2383
2384 no_route:
2385 RT_CACHE_STAT_INC(in_no_route);
2386 res->type = RTN_UNREACHABLE;
2387 res->fi = NULL;
2388 res->table = NULL;
2389 goto local_input;
2390
2391 /*
2392 * Do not cache martian addresses: they should be logged (RFC1812)
2393 */
2394 martian_destination:
2395 RT_CACHE_STAT_INC(in_martian_dst);
2396 #ifdef CONFIG_IP_ROUTE_VERBOSE
2397 if (IN_DEV_LOG_MARTIANS(in_dev))
2398 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2399 &daddr, &saddr, dev->name);
2400 #endif
2401
2402 e_inval:
2403 err = -EINVAL;
2404 goto out;
2405
2406 e_nobufs:
2407 err = -ENOBUFS;
2408 goto out;
2409
2410 martian_source:
2411 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2412 goto out;
2413 }
2414
ip_route_input_noref(struct sk_buff * skb,__be32 daddr,__be32 saddr,u8 tos,struct net_device * dev)2415 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2416 u8 tos, struct net_device *dev)
2417 {
2418 struct fib_result res;
2419 int err;
2420
2421 tos &= IPTOS_RT_MASK;
2422 rcu_read_lock();
2423 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2424 rcu_read_unlock();
2425
2426 return err;
2427 }
2428 EXPORT_SYMBOL(ip_route_input_noref);
2429
2430 /* 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)2431 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2432 u8 tos, struct net_device *dev, struct fib_result *res)
2433 {
2434 /* Multicast recognition logic is moved from route cache to here.
2435 * The problem was that too many Ethernet cards have broken/missing
2436 * hardware multicast filters :-( As result the host on multicasting
2437 * network acquires a lot of useless route cache entries, sort of
2438 * SDR messages from all the world. Now we try to get rid of them.
2439 * Really, provided software IP multicast filter is organized
2440 * reasonably (at least, hashed), it does not result in a slowdown
2441 * comparing with route cache reject entries.
2442 * Note, that multicast routers are not affected, because
2443 * route cache entry is created eventually.
2444 */
2445 if (ipv4_is_multicast(daddr)) {
2446 struct in_device *in_dev = __in_dev_get_rcu(dev);
2447 int our = 0;
2448 int err = -EINVAL;
2449
2450 if (!in_dev)
2451 return err;
2452 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2453 ip_hdr(skb)->protocol);
2454
2455 /* check l3 master if no match yet */
2456 if (!our && netif_is_l3_slave(dev)) {
2457 struct in_device *l3_in_dev;
2458
2459 l3_in_dev = __in_dev_get_rcu(skb->dev);
2460 if (l3_in_dev)
2461 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2462 ip_hdr(skb)->protocol);
2463 }
2464
2465 if (our
2466 #ifdef CONFIG_IP_MROUTE
2467 ||
2468 (!ipv4_is_local_multicast(daddr) &&
2469 IN_DEV_MFORWARD(in_dev))
2470 #endif
2471 ) {
2472 err = ip_route_input_mc(skb, daddr, saddr,
2473 tos, dev, our);
2474 }
2475 return err;
2476 }
2477
2478 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2479 }
2480
2481 /* 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)2482 static struct rtable *__mkroute_output(const struct fib_result *res,
2483 const struct flowi4 *fl4, int orig_oif,
2484 struct net_device *dev_out,
2485 unsigned int flags)
2486 {
2487 struct fib_info *fi = res->fi;
2488 struct fib_nh_exception *fnhe;
2489 struct in_device *in_dev;
2490 u16 type = res->type;
2491 struct rtable *rth;
2492 bool do_cache;
2493
2494 in_dev = __in_dev_get_rcu(dev_out);
2495 if (!in_dev)
2496 return ERR_PTR(-EINVAL);
2497
2498 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2499 if (ipv4_is_loopback(fl4->saddr) &&
2500 !(dev_out->flags & IFF_LOOPBACK) &&
2501 !netif_is_l3_master(dev_out))
2502 return ERR_PTR(-EINVAL);
2503
2504 if (ipv4_is_lbcast(fl4->daddr))
2505 type = RTN_BROADCAST;
2506 else if (ipv4_is_multicast(fl4->daddr))
2507 type = RTN_MULTICAST;
2508 else if (ipv4_is_zeronet(fl4->daddr))
2509 return ERR_PTR(-EINVAL);
2510
2511 if (dev_out->flags & IFF_LOOPBACK)
2512 flags |= RTCF_LOCAL;
2513
2514 do_cache = true;
2515 if (type == RTN_BROADCAST) {
2516 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2517 fi = NULL;
2518 } else if (type == RTN_MULTICAST) {
2519 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2520 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2521 fl4->flowi4_proto))
2522 flags &= ~RTCF_LOCAL;
2523 else
2524 do_cache = false;
2525 /* If multicast route do not exist use
2526 * default one, but do not gateway in this case.
2527 * Yes, it is hack.
2528 */
2529 if (fi && res->prefixlen < 4)
2530 fi = NULL;
2531 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2532 (orig_oif != dev_out->ifindex)) {
2533 /* For local routes that require a particular output interface
2534 * we do not want to cache the result. Caching the result
2535 * causes incorrect behaviour when there are multiple source
2536 * addresses on the interface, the end result being that if the
2537 * intended recipient is waiting on that interface for the
2538 * packet he won't receive it because it will be delivered on
2539 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2540 * be set to the loopback interface as well.
2541 */
2542 do_cache = false;
2543 }
2544
2545 fnhe = NULL;
2546 do_cache &= fi != NULL;
2547 if (fi) {
2548 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2549 struct rtable __rcu **prth;
2550
2551 fnhe = find_exception(nhc, fl4->daddr);
2552 if (!do_cache)
2553 goto add;
2554 if (fnhe) {
2555 prth = &fnhe->fnhe_rth_output;
2556 } else {
2557 if (unlikely(fl4->flowi4_flags &
2558 FLOWI_FLAG_KNOWN_NH &&
2559 !(nhc->nhc_gw_family &&
2560 nhc->nhc_scope == RT_SCOPE_LINK))) {
2561 do_cache = false;
2562 goto add;
2563 }
2564 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2565 }
2566 rth = rcu_dereference(*prth);
2567 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2568 return rth;
2569 }
2570
2571 add:
2572 rth = rt_dst_alloc(dev_out, flags, type,
2573 IN_DEV_ORCONF(in_dev, NOPOLICY),
2574 IN_DEV_ORCONF(in_dev, NOXFRM));
2575 if (!rth)
2576 return ERR_PTR(-ENOBUFS);
2577
2578 rth->rt_iif = orig_oif;
2579
2580 RT_CACHE_STAT_INC(out_slow_tot);
2581
2582 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2583 if (flags & RTCF_LOCAL &&
2584 !(dev_out->flags & IFF_LOOPBACK)) {
2585 rth->dst.output = ip_mc_output;
2586 RT_CACHE_STAT_INC(out_slow_mc);
2587 }
2588 #ifdef CONFIG_IP_MROUTE
2589 if (type == RTN_MULTICAST) {
2590 if (IN_DEV_MFORWARD(in_dev) &&
2591 !ipv4_is_local_multicast(fl4->daddr)) {
2592 rth->dst.input = ip_mr_input;
2593 rth->dst.output = ip_mc_output;
2594 }
2595 }
2596 #endif
2597 }
2598
2599 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2600 lwtunnel_set_redirect(&rth->dst);
2601
2602 return rth;
2603 }
2604
2605 /*
2606 * Major route resolver routine.
2607 */
2608
ip_route_output_key_hash(struct net * net,struct flowi4 * fl4,const struct sk_buff * skb)2609 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2610 const struct sk_buff *skb)
2611 {
2612 __u8 tos = RT_FL_TOS(fl4);
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 = tos & IPTOS_RT_MASK;
2623 fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
2624 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
2625
2626 rcu_read_lock();
2627 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2628 rcu_read_unlock();
2629
2630 return rth;
2631 }
2632 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2633
ip_route_output_key_hash_rcu(struct net * net,struct flowi4 * fl4,struct fib_result * res,const struct sk_buff * skb)2634 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2635 struct fib_result *res,
2636 const struct sk_buff *skb)
2637 {
2638 struct net_device *dev_out = NULL;
2639 int orig_oif = fl4->flowi4_oif;
2640 unsigned int flags = 0;
2641 struct rtable *rth;
2642 int err;
2643
2644 if (fl4->saddr) {
2645 if (ipv4_is_multicast(fl4->saddr) ||
2646 ipv4_is_lbcast(fl4->saddr) ||
2647 ipv4_is_zeronet(fl4->saddr)) {
2648 rth = ERR_PTR(-EINVAL);
2649 goto out;
2650 }
2651
2652 rth = ERR_PTR(-ENETUNREACH);
2653
2654 /* I removed check for oif == dev_out->oif here.
2655 * It was wrong for two reasons:
2656 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2657 * is assigned to multiple interfaces.
2658 * 2. Moreover, we are allowed to send packets with saddr
2659 * of another iface. --ANK
2660 */
2661
2662 if (fl4->flowi4_oif == 0 &&
2663 (ipv4_is_multicast(fl4->daddr) ||
2664 ipv4_is_lbcast(fl4->daddr))) {
2665 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2666 dev_out = __ip_dev_find(net, fl4->saddr, false);
2667 if (!dev_out)
2668 goto out;
2669
2670 /* Special hack: user can direct multicasts
2671 * and limited broadcast via necessary interface
2672 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2673 * This hack is not just for fun, it allows
2674 * vic,vat and friends to work.
2675 * They bind socket to loopback, set ttl to zero
2676 * and expect that it will work.
2677 * From the viewpoint of routing cache they are broken,
2678 * because we are not allowed to build multicast path
2679 * with loopback source addr (look, routing cache
2680 * cannot know, that ttl is zero, so that packet
2681 * will not leave this host and route is valid).
2682 * Luckily, this hack is good workaround.
2683 */
2684
2685 fl4->flowi4_oif = dev_out->ifindex;
2686 goto make_route;
2687 }
2688
2689 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2690 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2691 if (!__ip_dev_find(net, fl4->saddr, false))
2692 goto out;
2693 }
2694 }
2695
2696
2697 if (fl4->flowi4_oif) {
2698 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2699 rth = ERR_PTR(-ENODEV);
2700 if (!dev_out)
2701 goto out;
2702
2703 /* RACE: Check return value of inet_select_addr instead. */
2704 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2705 rth = ERR_PTR(-ENETUNREACH);
2706 goto out;
2707 }
2708 if (ipv4_is_local_multicast(fl4->daddr) ||
2709 ipv4_is_lbcast(fl4->daddr) ||
2710 fl4->flowi4_proto == IPPROTO_IGMP) {
2711 if (!fl4->saddr)
2712 fl4->saddr = inet_select_addr(dev_out, 0,
2713 RT_SCOPE_LINK);
2714 goto make_route;
2715 }
2716 if (!fl4->saddr) {
2717 if (ipv4_is_multicast(fl4->daddr))
2718 fl4->saddr = inet_select_addr(dev_out, 0,
2719 fl4->flowi4_scope);
2720 else if (!fl4->daddr)
2721 fl4->saddr = inet_select_addr(dev_out, 0,
2722 RT_SCOPE_HOST);
2723 }
2724 }
2725
2726 if (!fl4->daddr) {
2727 fl4->daddr = fl4->saddr;
2728 if (!fl4->daddr)
2729 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2730 dev_out = net->loopback_dev;
2731 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2732 res->type = RTN_LOCAL;
2733 flags |= RTCF_LOCAL;
2734 goto make_route;
2735 }
2736
2737 err = fib_lookup(net, fl4, res, 0);
2738 if (err) {
2739 res->fi = NULL;
2740 res->table = NULL;
2741 if (fl4->flowi4_oif &&
2742 (ipv4_is_multicast(fl4->daddr) ||
2743 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2744 /* Apparently, routing tables are wrong. Assume,
2745 * that the destination is on link.
2746 *
2747 * WHY? DW.
2748 * Because we are allowed to send to iface
2749 * even if it has NO routes and NO assigned
2750 * addresses. When oif is specified, routing
2751 * tables are looked up with only one purpose:
2752 * to catch if destination is gatewayed, rather than
2753 * direct. Moreover, if MSG_DONTROUTE is set,
2754 * we send packet, ignoring both routing tables
2755 * and ifaddr state. --ANK
2756 *
2757 *
2758 * We could make it even if oif is unknown,
2759 * likely IPv6, but we do not.
2760 */
2761
2762 if (fl4->saddr == 0)
2763 fl4->saddr = inet_select_addr(dev_out, 0,
2764 RT_SCOPE_LINK);
2765 res->type = RTN_UNICAST;
2766 goto make_route;
2767 }
2768 rth = ERR_PTR(err);
2769 goto out;
2770 }
2771
2772 if (res->type == RTN_LOCAL) {
2773 if (!fl4->saddr) {
2774 if (res->fi->fib_prefsrc)
2775 fl4->saddr = res->fi->fib_prefsrc;
2776 else
2777 fl4->saddr = fl4->daddr;
2778 }
2779
2780 /* L3 master device is the loopback for that domain */
2781 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2782 net->loopback_dev;
2783
2784 /* make sure orig_oif points to fib result device even
2785 * though packet rx/tx happens over loopback or l3mdev
2786 */
2787 orig_oif = FIB_RES_OIF(*res);
2788
2789 fl4->flowi4_oif = dev_out->ifindex;
2790 flags |= RTCF_LOCAL;
2791 goto make_route;
2792 }
2793
2794 fib_select_path(net, res, fl4, skb);
2795
2796 dev_out = FIB_RES_DEV(*res);
2797
2798 make_route:
2799 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2800
2801 out:
2802 return rth;
2803 }
2804
2805 static struct dst_ops ipv4_dst_blackhole_ops = {
2806 .family = AF_INET,
2807 .default_advmss = ipv4_default_advmss,
2808 .neigh_lookup = ipv4_neigh_lookup,
2809 .check = dst_blackhole_check,
2810 .cow_metrics = dst_blackhole_cow_metrics,
2811 .update_pmtu = dst_blackhole_update_pmtu,
2812 .redirect = dst_blackhole_redirect,
2813 .mtu = dst_blackhole_mtu,
2814 };
2815
ipv4_blackhole_route(struct net * net,struct dst_entry * dst_orig)2816 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2817 {
2818 struct rtable *ort = (struct rtable *) dst_orig;
2819 struct rtable *rt;
2820
2821 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2822 if (rt) {
2823 struct dst_entry *new = &rt->dst;
2824
2825 new->__use = 1;
2826 new->input = dst_discard;
2827 new->output = dst_discard_out;
2828
2829 new->dev = net->loopback_dev;
2830 dev_hold(new->dev);
2831
2832 rt->rt_is_input = ort->rt_is_input;
2833 rt->rt_iif = ort->rt_iif;
2834 rt->rt_pmtu = ort->rt_pmtu;
2835 rt->rt_mtu_locked = ort->rt_mtu_locked;
2836
2837 rt->rt_genid = rt_genid_ipv4(net);
2838 rt->rt_flags = ort->rt_flags;
2839 rt->rt_type = ort->rt_type;
2840 rt->rt_uses_gateway = ort->rt_uses_gateway;
2841 rt->rt_gw_family = ort->rt_gw_family;
2842 if (rt->rt_gw_family == AF_INET)
2843 rt->rt_gw4 = ort->rt_gw4;
2844 else if (rt->rt_gw_family == AF_INET6)
2845 rt->rt_gw6 = ort->rt_gw6;
2846
2847 INIT_LIST_HEAD(&rt->rt_uncached);
2848 }
2849
2850 dst_release(dst_orig);
2851
2852 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2853 }
2854
ip_route_output_flow(struct net * net,struct flowi4 * flp4,const struct sock * sk)2855 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2856 const struct sock *sk)
2857 {
2858 struct rtable *rt = __ip_route_output_key(net, flp4);
2859
2860 if (IS_ERR(rt))
2861 return rt;
2862
2863 if (flp4->flowi4_proto) {
2864 flp4->flowi4_oif = rt->dst.dev->ifindex;
2865 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2866 flowi4_to_flowi(flp4),
2867 sk, 0);
2868 }
2869
2870 return rt;
2871 }
2872 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2873
ip_route_output_tunnel(struct sk_buff * skb,struct net_device * dev,struct net * net,__be32 * saddr,const struct ip_tunnel_info * info,u8 protocol,bool use_cache)2874 struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
2875 struct net_device *dev,
2876 struct net *net, __be32 *saddr,
2877 const struct ip_tunnel_info *info,
2878 u8 protocol, bool use_cache)
2879 {
2880 #ifdef CONFIG_DST_CACHE
2881 struct dst_cache *dst_cache;
2882 #endif
2883 struct rtable *rt = NULL;
2884 struct flowi4 fl4;
2885 __u8 tos;
2886
2887 #ifdef CONFIG_DST_CACHE
2888 dst_cache = (struct dst_cache *)&info->dst_cache;
2889 if (use_cache) {
2890 rt = dst_cache_get_ip4(dst_cache, saddr);
2891 if (rt)
2892 return rt;
2893 }
2894 #endif
2895 memset(&fl4, 0, sizeof(fl4));
2896 fl4.flowi4_mark = skb->mark;
2897 fl4.flowi4_proto = protocol;
2898 fl4.daddr = info->key.u.ipv4.dst;
2899 fl4.saddr = info->key.u.ipv4.src;
2900 tos = info->key.tos;
2901 fl4.flowi4_tos = RT_TOS(tos);
2902
2903 rt = ip_route_output_key(net, &fl4);
2904 if (IS_ERR(rt)) {
2905 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr);
2906 return ERR_PTR(-ENETUNREACH);
2907 }
2908 if (rt->dst.dev == dev) { /* is this necessary? */
2909 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr);
2910 ip_rt_put(rt);
2911 return ERR_PTR(-ELOOP);
2912 }
2913 #ifdef CONFIG_DST_CACHE
2914 if (use_cache)
2915 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
2916 #endif
2917 *saddr = fl4.saddr;
2918 return rt;
2919 }
2920 EXPORT_SYMBOL_GPL(ip_route_output_tunnel);
2921
2922 /* 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)2923 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2924 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2925 struct sk_buff *skb, u32 portid, u32 seq,
2926 unsigned int flags)
2927 {
2928 struct rtmsg *r;
2929 struct nlmsghdr *nlh;
2930 unsigned long expires = 0;
2931 u32 error;
2932 u32 metrics[RTAX_MAX];
2933
2934 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2935 if (!nlh)
2936 return -EMSGSIZE;
2937
2938 r = nlmsg_data(nlh);
2939 r->rtm_family = AF_INET;
2940 r->rtm_dst_len = 32;
2941 r->rtm_src_len = 0;
2942 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2943 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2944 if (nla_put_u32(skb, RTA_TABLE, table_id))
2945 goto nla_put_failure;
2946 r->rtm_type = rt->rt_type;
2947 r->rtm_scope = RT_SCOPE_UNIVERSE;
2948 r->rtm_protocol = RTPROT_UNSPEC;
2949 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2950 if (rt->rt_flags & RTCF_NOTIFY)
2951 r->rtm_flags |= RTM_F_NOTIFY;
2952 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2953 r->rtm_flags |= RTCF_DOREDIRECT;
2954
2955 if (nla_put_in_addr(skb, RTA_DST, dst))
2956 goto nla_put_failure;
2957 if (src) {
2958 r->rtm_src_len = 32;
2959 if (nla_put_in_addr(skb, RTA_SRC, src))
2960 goto nla_put_failure;
2961 }
2962 if (rt->dst.dev &&
2963 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2964 goto nla_put_failure;
2965 if (rt->dst.lwtstate &&
2966 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
2967 goto nla_put_failure;
2968 #ifdef CONFIG_IP_ROUTE_CLASSID
2969 if (rt->dst.tclassid &&
2970 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2971 goto nla_put_failure;
2972 #endif
2973 if (fl4 && !rt_is_input_route(rt) &&
2974 fl4->saddr != src) {
2975 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
2976 goto nla_put_failure;
2977 }
2978 if (rt->rt_uses_gateway) {
2979 if (rt->rt_gw_family == AF_INET &&
2980 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
2981 goto nla_put_failure;
2982 } else if (rt->rt_gw_family == AF_INET6) {
2983 int alen = sizeof(struct in6_addr);
2984 struct nlattr *nla;
2985 struct rtvia *via;
2986
2987 nla = nla_reserve(skb, RTA_VIA, alen + 2);
2988 if (!nla)
2989 goto nla_put_failure;
2990
2991 via = nla_data(nla);
2992 via->rtvia_family = AF_INET6;
2993 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2994 }
2995 }
2996
2997 expires = rt->dst.expires;
2998 if (expires) {
2999 unsigned long now = jiffies;
3000
3001 if (time_before(now, expires))
3002 expires -= now;
3003 else
3004 expires = 0;
3005 }
3006
3007 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
3008 if (rt->rt_pmtu && expires)
3009 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
3010 if (rt->rt_mtu_locked && expires)
3011 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
3012 if (rtnetlink_put_metrics(skb, metrics) < 0)
3013 goto nla_put_failure;
3014
3015 if (fl4) {
3016 if (fl4->flowi4_mark &&
3017 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
3018 goto nla_put_failure;
3019
3020 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
3021 nla_put_u32(skb, RTA_UID,
3022 from_kuid_munged(current_user_ns(),
3023 fl4->flowi4_uid)))
3024 goto nla_put_failure;
3025
3026 if (rt_is_input_route(rt)) {
3027 #ifdef CONFIG_IP_MROUTE
3028 if (ipv4_is_multicast(dst) &&
3029 !ipv4_is_local_multicast(dst) &&
3030 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
3031 int err = ipmr_get_route(net, skb,
3032 fl4->saddr, fl4->daddr,
3033 r, portid);
3034
3035 if (err <= 0) {
3036 if (err == 0)
3037 return 0;
3038 goto nla_put_failure;
3039 }
3040 } else
3041 #endif
3042 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
3043 goto nla_put_failure;
3044 }
3045 }
3046
3047 error = rt->dst.error;
3048
3049 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
3050 goto nla_put_failure;
3051
3052 nlmsg_end(skb, nlh);
3053 return 0;
3054
3055 nla_put_failure:
3056 nlmsg_cancel(skb, nlh);
3057 return -EMSGSIZE;
3058 }
3059
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)3060 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3061 struct netlink_callback *cb, u32 table_id,
3062 struct fnhe_hash_bucket *bucket, int genid,
3063 int *fa_index, int fa_start, unsigned int flags)
3064 {
3065 int i;
3066
3067 for (i = 0; i < FNHE_HASH_SIZE; i++) {
3068 struct fib_nh_exception *fnhe;
3069
3070 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3071 fnhe = rcu_dereference(fnhe->fnhe_next)) {
3072 struct rtable *rt;
3073 int err;
3074
3075 if (*fa_index < fa_start)
3076 goto next;
3077
3078 if (fnhe->fnhe_genid != genid)
3079 goto next;
3080
3081 if (fnhe->fnhe_expires &&
3082 time_after(jiffies, fnhe->fnhe_expires))
3083 goto next;
3084
3085 rt = rcu_dereference(fnhe->fnhe_rth_input);
3086 if (!rt)
3087 rt = rcu_dereference(fnhe->fnhe_rth_output);
3088 if (!rt)
3089 goto next;
3090
3091 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
3092 table_id, NULL, skb,
3093 NETLINK_CB(cb->skb).portid,
3094 cb->nlh->nlmsg_seq, flags);
3095 if (err)
3096 return err;
3097 next:
3098 (*fa_index)++;
3099 }
3100 }
3101
3102 return 0;
3103 }
3104
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)3105 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3106 u32 table_id, struct fib_info *fi,
3107 int *fa_index, int fa_start, unsigned int flags)
3108 {
3109 struct net *net = sock_net(cb->skb->sk);
3110 int nhsel, genid = fnhe_genid(net);
3111
3112 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3113 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3114 struct fnhe_hash_bucket *bucket;
3115 int err;
3116
3117 if (nhc->nhc_flags & RTNH_F_DEAD)
3118 continue;
3119
3120 rcu_read_lock();
3121 bucket = rcu_dereference(nhc->nhc_exceptions);
3122 err = 0;
3123 if (bucket)
3124 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3125 genid, fa_index, fa_start,
3126 flags);
3127 rcu_read_unlock();
3128 if (err)
3129 return err;
3130 }
3131
3132 return 0;
3133 }
3134
inet_rtm_getroute_build_skb(__be32 src,__be32 dst,u8 ip_proto,__be16 sport,__be16 dport)3135 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3136 u8 ip_proto, __be16 sport,
3137 __be16 dport)
3138 {
3139 struct sk_buff *skb;
3140 struct iphdr *iph;
3141
3142 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3143 if (!skb)
3144 return NULL;
3145
3146 /* Reserve room for dummy headers, this skb can pass
3147 * through good chunk of routing engine.
3148 */
3149 skb_reset_mac_header(skb);
3150 skb_reset_network_header(skb);
3151 skb->protocol = htons(ETH_P_IP);
3152 iph = skb_put(skb, sizeof(struct iphdr));
3153 iph->protocol = ip_proto;
3154 iph->saddr = src;
3155 iph->daddr = dst;
3156 iph->version = 0x4;
3157 iph->frag_off = 0;
3158 iph->ihl = 0x5;
3159 skb_set_transport_header(skb, skb->len);
3160
3161 switch (iph->protocol) {
3162 case IPPROTO_UDP: {
3163 struct udphdr *udph;
3164
3165 udph = skb_put_zero(skb, sizeof(struct udphdr));
3166 udph->source = sport;
3167 udph->dest = dport;
3168 udph->len = htons(sizeof(struct udphdr));
3169 udph->check = 0;
3170 break;
3171 }
3172 case IPPROTO_TCP: {
3173 struct tcphdr *tcph;
3174
3175 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3176 tcph->source = sport;
3177 tcph->dest = dport;
3178 tcph->doff = sizeof(struct tcphdr) / 4;
3179 tcph->rst = 1;
3180 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3181 src, dst, 0);
3182 break;
3183 }
3184 case IPPROTO_ICMP: {
3185 struct icmphdr *icmph;
3186
3187 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3188 icmph->type = ICMP_ECHO;
3189 icmph->code = 0;
3190 }
3191 }
3192
3193 return skb;
3194 }
3195
inet_rtm_valid_getroute_req(struct sk_buff * skb,const struct nlmsghdr * nlh,struct nlattr ** tb,struct netlink_ext_ack * extack)3196 static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3197 const struct nlmsghdr *nlh,
3198 struct nlattr **tb,
3199 struct netlink_ext_ack *extack)
3200 {
3201 struct rtmsg *rtm;
3202 int i, err;
3203
3204 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3205 NL_SET_ERR_MSG(extack,
3206 "ipv4: Invalid header for route get request");
3207 return -EINVAL;
3208 }
3209
3210 if (!netlink_strict_get_check(skb))
3211 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3212 rtm_ipv4_policy, extack);
3213
3214 rtm = nlmsg_data(nlh);
3215 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3216 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3217 rtm->rtm_table || rtm->rtm_protocol ||
3218 rtm->rtm_scope || rtm->rtm_type) {
3219 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3220 return -EINVAL;
3221 }
3222
3223 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3224 RTM_F_LOOKUP_TABLE |
3225 RTM_F_FIB_MATCH)) {
3226 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3227 return -EINVAL;
3228 }
3229
3230 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3231 rtm_ipv4_policy, extack);
3232 if (err)
3233 return err;
3234
3235 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3236 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3237 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3238 return -EINVAL;
3239 }
3240
3241 for (i = 0; i <= RTA_MAX; i++) {
3242 if (!tb[i])
3243 continue;
3244
3245 switch (i) {
3246 case RTA_IIF:
3247 case RTA_OIF:
3248 case RTA_SRC:
3249 case RTA_DST:
3250 case RTA_IP_PROTO:
3251 case RTA_SPORT:
3252 case RTA_DPORT:
3253 case RTA_MARK:
3254 case RTA_UID:
3255 break;
3256 default:
3257 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3258 return -EINVAL;
3259 }
3260 }
3261
3262 return 0;
3263 }
3264
inet_rtm_getroute(struct sk_buff * in_skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)3265 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3266 struct netlink_ext_ack *extack)
3267 {
3268 struct net *net = sock_net(in_skb->sk);
3269 struct nlattr *tb[RTA_MAX+1];
3270 u32 table_id = RT_TABLE_MAIN;
3271 __be16 sport = 0, dport = 0;
3272 struct fib_result res = {};
3273 u8 ip_proto = IPPROTO_UDP;
3274 struct rtable *rt = NULL;
3275 struct sk_buff *skb;
3276 struct rtmsg *rtm;
3277 struct flowi4 fl4 = {};
3278 __be32 dst = 0;
3279 __be32 src = 0;
3280 kuid_t uid;
3281 u32 iif;
3282 int err;
3283 int mark;
3284
3285 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3286 if (err < 0)
3287 return err;
3288
3289 rtm = nlmsg_data(nlh);
3290 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3291 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3292 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3293 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3294 if (tb[RTA_UID])
3295 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3296 else
3297 uid = (iif ? INVALID_UID : current_uid());
3298
3299 if (tb[RTA_IP_PROTO]) {
3300 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3301 &ip_proto, AF_INET, extack);
3302 if (err)
3303 return err;
3304 }
3305
3306 if (tb[RTA_SPORT])
3307 sport = nla_get_be16(tb[RTA_SPORT]);
3308
3309 if (tb[RTA_DPORT])
3310 dport = nla_get_be16(tb[RTA_DPORT]);
3311
3312 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3313 if (!skb)
3314 return -ENOBUFS;
3315
3316 fl4.daddr = dst;
3317 fl4.saddr = src;
3318 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK;
3319 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3320 fl4.flowi4_mark = mark;
3321 fl4.flowi4_uid = uid;
3322 if (sport)
3323 fl4.fl4_sport = sport;
3324 if (dport)
3325 fl4.fl4_dport = dport;
3326 fl4.flowi4_proto = ip_proto;
3327
3328 rcu_read_lock();
3329
3330 if (iif) {
3331 struct net_device *dev;
3332
3333 dev = dev_get_by_index_rcu(net, iif);
3334 if (!dev) {
3335 err = -ENODEV;
3336 goto errout_rcu;
3337 }
3338
3339 fl4.flowi4_iif = iif; /* for rt_fill_info */
3340 skb->dev = dev;
3341 skb->mark = mark;
3342 err = ip_route_input_rcu(skb, dst, src,
3343 rtm->rtm_tos & IPTOS_RT_MASK, dev,
3344 &res);
3345
3346 rt = skb_rtable(skb);
3347 if (err == 0 && rt->dst.error)
3348 err = -rt->dst.error;
3349 } else {
3350 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3351 skb->dev = net->loopback_dev;
3352 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3353 err = 0;
3354 if (IS_ERR(rt))
3355 err = PTR_ERR(rt);
3356 else
3357 skb_dst_set(skb, &rt->dst);
3358 }
3359
3360 if (err)
3361 goto errout_rcu;
3362
3363 if (rtm->rtm_flags & RTM_F_NOTIFY)
3364 rt->rt_flags |= RTCF_NOTIFY;
3365
3366 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3367 table_id = res.table ? res.table->tb_id : 0;
3368
3369 /* reset skb for netlink reply msg */
3370 skb_trim(skb, 0);
3371 skb_reset_network_header(skb);
3372 skb_reset_transport_header(skb);
3373 skb_reset_mac_header(skb);
3374
3375 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3376 struct fib_rt_info fri;
3377
3378 if (!res.fi) {
3379 err = fib_props[res.type].error;
3380 if (!err)
3381 err = -EHOSTUNREACH;
3382 goto errout_rcu;
3383 }
3384 fri.fi = res.fi;
3385 fri.tb_id = table_id;
3386 fri.dst = res.prefix;
3387 fri.dst_len = res.prefixlen;
3388 fri.tos = fl4.flowi4_tos;
3389 fri.type = rt->rt_type;
3390 fri.offload = 0;
3391 fri.trap = 0;
3392 fri.offload_failed = 0;
3393 if (res.fa_head) {
3394 struct fib_alias *fa;
3395
3396 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3397 u8 slen = 32 - fri.dst_len;
3398
3399 if (fa->fa_slen == slen &&
3400 fa->tb_id == fri.tb_id &&
3401 fa->fa_tos == fri.tos &&
3402 fa->fa_info == res.fi &&
3403 fa->fa_type == fri.type) {
3404 fri.offload = fa->offload;
3405 fri.trap = fa->trap;
3406 break;
3407 }
3408 }
3409 }
3410 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3411 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3412 } else {
3413 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3414 NETLINK_CB(in_skb).portid,
3415 nlh->nlmsg_seq, 0);
3416 }
3417 if (err < 0)
3418 goto errout_rcu;
3419
3420 rcu_read_unlock();
3421
3422 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3423
3424 errout_free:
3425 return err;
3426 errout_rcu:
3427 rcu_read_unlock();
3428 kfree_skb(skb);
3429 goto errout_free;
3430 }
3431
ip_rt_multicast_event(struct in_device * in_dev)3432 void ip_rt_multicast_event(struct in_device *in_dev)
3433 {
3434 rt_cache_flush(dev_net(in_dev->dev));
3435 }
3436
3437 #ifdef CONFIG_SYSCTL
3438 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3439 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3440 static int ip_rt_gc_elasticity __read_mostly = 8;
3441 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3442
ipv4_sysctl_rtcache_flush(struct ctl_table * __ctl,int write,void * buffer,size_t * lenp,loff_t * ppos)3443 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3444 void *buffer, size_t *lenp, loff_t *ppos)
3445 {
3446 struct net *net = (struct net *)__ctl->extra1;
3447
3448 if (write) {
3449 rt_cache_flush(net);
3450 fnhe_genid_bump(net);
3451 return 0;
3452 }
3453
3454 return -EINVAL;
3455 }
3456
3457 static struct ctl_table ipv4_route_table[] = {
3458 {
3459 .procname = "gc_thresh",
3460 .data = &ipv4_dst_ops.gc_thresh,
3461 .maxlen = sizeof(int),
3462 .mode = 0644,
3463 .proc_handler = proc_dointvec,
3464 },
3465 {
3466 .procname = "max_size",
3467 .data = &ip_rt_max_size,
3468 .maxlen = sizeof(int),
3469 .mode = 0644,
3470 .proc_handler = proc_dointvec,
3471 },
3472 {
3473 /* Deprecated. Use gc_min_interval_ms */
3474
3475 .procname = "gc_min_interval",
3476 .data = &ip_rt_gc_min_interval,
3477 .maxlen = sizeof(int),
3478 .mode = 0644,
3479 .proc_handler = proc_dointvec_jiffies,
3480 },
3481 {
3482 .procname = "gc_min_interval_ms",
3483 .data = &ip_rt_gc_min_interval,
3484 .maxlen = sizeof(int),
3485 .mode = 0644,
3486 .proc_handler = proc_dointvec_ms_jiffies,
3487 },
3488 {
3489 .procname = "gc_timeout",
3490 .data = &ip_rt_gc_timeout,
3491 .maxlen = sizeof(int),
3492 .mode = 0644,
3493 .proc_handler = proc_dointvec_jiffies,
3494 },
3495 {
3496 .procname = "gc_interval",
3497 .data = &ip_rt_gc_interval,
3498 .maxlen = sizeof(int),
3499 .mode = 0644,
3500 .proc_handler = proc_dointvec_jiffies,
3501 },
3502 {
3503 .procname = "redirect_load",
3504 .data = &ip_rt_redirect_load,
3505 .maxlen = sizeof(int),
3506 .mode = 0644,
3507 .proc_handler = proc_dointvec,
3508 },
3509 {
3510 .procname = "redirect_number",
3511 .data = &ip_rt_redirect_number,
3512 .maxlen = sizeof(int),
3513 .mode = 0644,
3514 .proc_handler = proc_dointvec,
3515 },
3516 {
3517 .procname = "redirect_silence",
3518 .data = &ip_rt_redirect_silence,
3519 .maxlen = sizeof(int),
3520 .mode = 0644,
3521 .proc_handler = proc_dointvec,
3522 },
3523 {
3524 .procname = "error_cost",
3525 .data = &ip_rt_error_cost,
3526 .maxlen = sizeof(int),
3527 .mode = 0644,
3528 .proc_handler = proc_dointvec,
3529 },
3530 {
3531 .procname = "error_burst",
3532 .data = &ip_rt_error_burst,
3533 .maxlen = sizeof(int),
3534 .mode = 0644,
3535 .proc_handler = proc_dointvec,
3536 },
3537 {
3538 .procname = "gc_elasticity",
3539 .data = &ip_rt_gc_elasticity,
3540 .maxlen = sizeof(int),
3541 .mode = 0644,
3542 .proc_handler = proc_dointvec,
3543 },
3544 {
3545 .procname = "mtu_expires",
3546 .data = &ip_rt_mtu_expires,
3547 .maxlen = sizeof(int),
3548 .mode = 0644,
3549 .proc_handler = proc_dointvec_jiffies,
3550 },
3551 {
3552 .procname = "min_pmtu",
3553 .data = &ip_rt_min_pmtu,
3554 .maxlen = sizeof(int),
3555 .mode = 0644,
3556 .proc_handler = proc_dointvec_minmax,
3557 .extra1 = &ip_min_valid_pmtu,
3558 },
3559 {
3560 .procname = "min_adv_mss",
3561 .data = &ip_rt_min_advmss,
3562 .maxlen = sizeof(int),
3563 .mode = 0644,
3564 .proc_handler = proc_dointvec,
3565 },
3566 { }
3567 };
3568
3569 static const char ipv4_route_flush_procname[] = "flush";
3570
3571 static struct ctl_table ipv4_route_flush_table[] = {
3572 {
3573 .procname = ipv4_route_flush_procname,
3574 .maxlen = sizeof(int),
3575 .mode = 0200,
3576 .proc_handler = ipv4_sysctl_rtcache_flush,
3577 },
3578 { },
3579 };
3580
sysctl_route_net_init(struct net * net)3581 static __net_init int sysctl_route_net_init(struct net *net)
3582 {
3583 struct ctl_table *tbl;
3584
3585 tbl = ipv4_route_flush_table;
3586 if (!net_eq(net, &init_net)) {
3587 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3588 if (!tbl)
3589 goto err_dup;
3590
3591 /* Don't export non-whitelisted sysctls to unprivileged users */
3592 if (net->user_ns != &init_user_ns) {
3593 if (tbl[0].procname != ipv4_route_flush_procname)
3594 tbl[0].procname = NULL;
3595 }
3596 }
3597 tbl[0].extra1 = net;
3598
3599 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3600 if (!net->ipv4.route_hdr)
3601 goto err_reg;
3602 return 0;
3603
3604 err_reg:
3605 if (tbl != ipv4_route_flush_table)
3606 kfree(tbl);
3607 err_dup:
3608 return -ENOMEM;
3609 }
3610
sysctl_route_net_exit(struct net * net)3611 static __net_exit void sysctl_route_net_exit(struct net *net)
3612 {
3613 struct ctl_table *tbl;
3614
3615 tbl = net->ipv4.route_hdr->ctl_table_arg;
3616 unregister_net_sysctl_table(net->ipv4.route_hdr);
3617 BUG_ON(tbl == ipv4_route_flush_table);
3618 kfree(tbl);
3619 }
3620
3621 static __net_initdata struct pernet_operations sysctl_route_ops = {
3622 .init = sysctl_route_net_init,
3623 .exit = sysctl_route_net_exit,
3624 };
3625 #endif
3626
rt_genid_init(struct net * net)3627 static __net_init int rt_genid_init(struct net *net)
3628 {
3629 atomic_set(&net->ipv4.rt_genid, 0);
3630 atomic_set(&net->fnhe_genid, 0);
3631 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3632 return 0;
3633 }
3634
3635 static __net_initdata struct pernet_operations rt_genid_ops = {
3636 .init = rt_genid_init,
3637 };
3638
ipv4_inetpeer_init(struct net * net)3639 static int __net_init ipv4_inetpeer_init(struct net *net)
3640 {
3641 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3642
3643 if (!bp)
3644 return -ENOMEM;
3645 inet_peer_base_init(bp);
3646 net->ipv4.peers = bp;
3647 return 0;
3648 }
3649
ipv4_inetpeer_exit(struct net * net)3650 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3651 {
3652 struct inet_peer_base *bp = net->ipv4.peers;
3653
3654 net->ipv4.peers = NULL;
3655 inetpeer_invalidate_tree(bp);
3656 kfree(bp);
3657 }
3658
3659 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3660 .init = ipv4_inetpeer_init,
3661 .exit = ipv4_inetpeer_exit,
3662 };
3663
3664 #ifdef CONFIG_IP_ROUTE_CLASSID
3665 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3666 #endif /* CONFIG_IP_ROUTE_CLASSID */
3667
ip_rt_init(void)3668 int __init ip_rt_init(void)
3669 {
3670 void *idents_hash;
3671 int cpu;
3672
3673 /* For modern hosts, this will use 2 MB of memory */
3674 idents_hash = alloc_large_system_hash("IP idents",
3675 sizeof(*ip_idents) + sizeof(*ip_tstamps),
3676 0,
3677 16, /* one bucket per 64 KB */
3678 HASH_ZERO,
3679 NULL,
3680 &ip_idents_mask,
3681 2048,
3682 256*1024);
3683
3684 ip_idents = idents_hash;
3685
3686 prandom_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
3687
3688 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3689
3690 for_each_possible_cpu(cpu) {
3691 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3692
3693 INIT_LIST_HEAD(&ul->head);
3694 spin_lock_init(&ul->lock);
3695 }
3696 #ifdef CONFIG_IP_ROUTE_CLASSID
3697 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3698 if (!ip_rt_acct)
3699 panic("IP: failed to allocate ip_rt_acct\n");
3700 #endif
3701
3702 ipv4_dst_ops.kmem_cachep =
3703 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3704 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3705
3706 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3707
3708 if (dst_entries_init(&ipv4_dst_ops) < 0)
3709 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3710
3711 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3712 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3713
3714 ipv4_dst_ops.gc_thresh = ~0;
3715 ip_rt_max_size = INT_MAX;
3716
3717 devinet_init();
3718 ip_fib_init();
3719
3720 if (ip_rt_proc_init())
3721 pr_err("Unable to create route proc files\n");
3722 #ifdef CONFIG_XFRM
3723 xfrm_init();
3724 xfrm4_init();
3725 #endif
3726 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3727 RTNL_FLAG_DOIT_UNLOCKED);
3728
3729 #ifdef CONFIG_SYSCTL
3730 register_pernet_subsys(&sysctl_route_ops);
3731 #endif
3732 register_pernet_subsys(&rt_genid_ops);
3733 register_pernet_subsys(&ipv4_inetpeer_ops);
3734 return 0;
3735 }
3736
3737 #ifdef CONFIG_SYSCTL
3738 /*
3739 * We really need to sanitize the damn ipv4 init order, then all
3740 * this nonsense will go away.
3741 */
ip_static_sysctl_init(void)3742 void __init ip_static_sysctl_init(void)
3743 {
3744 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3745 }
3746 #endif
3747
