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