1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * ROUTE - implementation of the IP router.
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Alan Cox, <gw4pts@gw4pts.ampr.org>
12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
14 *
15 * Fixes:
16 * Alan Cox : Verify area fixes.
17 * Alan Cox : cli() protects routing changes
18 * Rui Oliveira : ICMP routing table updates
19 * (rco@di.uminho.pt) Routing table insertion and update
20 * Linus Torvalds : Rewrote bits to be sensible
21 * Alan Cox : Added BSD route gw semantics
22 * Alan Cox : Super /proc >4K
23 * Alan Cox : MTU in route table
24 * Alan Cox : MSS actually. Also added the window
25 * clamper.
26 * Sam Lantinga : Fixed route matching in rt_del()
27 * Alan Cox : Routing cache support.
28 * Alan Cox : Removed compatibility cruft.
29 * Alan Cox : RTF_REJECT support.
30 * Alan Cox : TCP irtt support.
31 * Jonathan Naylor : Added Metric support.
32 * Miquel van Smoorenburg : BSD API fixes.
33 * Miquel van Smoorenburg : Metrics.
34 * Alan Cox : Use __u32 properly
35 * Alan Cox : Aligned routing errors more closely with BSD
36 * our system is still very different.
37 * Alan Cox : Faster /proc handling
38 * Alexey Kuznetsov : Massive rework to support tree based routing,
39 * routing caches and better behaviour.
40 *
41 * Olaf Erb : irtt wasn't being copied right.
42 * Bjorn Ekwall : Kerneld route support.
43 * Alan Cox : Multicast fixed (I hope)
44 * Pavel Krauz : Limited broadcast fixed
45 * Mike McLagan : Routing by source
46 * Alexey Kuznetsov : End of old history. Split to fib.c and
47 * route.c and rewritten from scratch.
48 * Andi Kleen : Load-limit warning messages.
49 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
53 * Marc Boucher : routing by fwmark
54 * Robert Olsson : Added rt_cache statistics
55 * Arnaldo C. Melo : Convert proc stuff to seq_file
56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
58 * Ilia Sotnikov : Removed TOS from hash calculations
59 */
60
61 #define pr_fmt(fmt) "IPv4: " fmt
62
63 #include <linux/module.h>
64 #include <linux/uaccess.h>
65 #include <linux/bitops.h>
66 #include <linux/types.h>
67 #include <linux/kernel.h>
68 #include <linux/mm.h>
69 #include <linux/memblock.h>
70 #include <linux/string.h>
71 #include <linux/socket.h>
72 #include <linux/sockios.h>
73 #include <linux/errno.h>
74 #include <linux/in.h>
75 #include <linux/inet.h>
76 #include <linux/netdevice.h>
77 #include <linux/proc_fs.h>
78 #include <linux/init.h>
79 #include <linux/skbuff.h>
80 #include <linux/inetdevice.h>
81 #include <linux/igmp.h>
82 #include <linux/pkt_sched.h>
83 #include <linux/mroute.h>
84 #include <linux/netfilter_ipv4.h>
85 #include <linux/random.h>
86 #include <linux/rcupdate.h>
87 #include <linux/times.h>
88 #include <linux/slab.h>
89 #include <linux/jhash.h>
90 #include <net/dst.h>
91 #include <net/dst_metadata.h>
92 #include <net/net_namespace.h>
93 #include <net/protocol.h>
94 #include <net/ip.h>
95 #include <net/route.h>
96 #include <net/inetpeer.h>
97 #include <net/sock.h>
98 #include <net/ip_fib.h>
99 #include <net/nexthop.h>
100 #include <net/arp.h>
101 #include <net/tcp.h>
102 #include <net/icmp.h>
103 #include <net/xfrm.h>
104 #include <net/lwtunnel.h>
105 #include <net/netevent.h>
106 #include <net/rtnetlink.h>
107 #ifdef CONFIG_SYSCTL
108 #include <linux/sysctl.h>
109 #endif
110 #include <net/secure_seq.h>
111 #include <net/ip_tunnels.h>
112 #include <net/l3mdev.h>
113
114 #include "fib_lookup.h"
115
116 #define RT_FL_TOS(oldflp4) \
117 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
118
119 #define RT_GC_TIMEOUT (300*HZ)
120
121 static int ip_rt_max_size;
122 static int ip_rt_redirect_number __read_mostly = 9;
123 static int ip_rt_redirect_load __read_mostly = HZ / 50;
124 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
125 static int ip_rt_error_cost __read_mostly = HZ;
126 static int ip_rt_error_burst __read_mostly = 5 * HZ;
127 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ;
128 static u32 ip_rt_min_pmtu __read_mostly = 512 + 20 + 20;
129 static int ip_rt_min_advmss __read_mostly = 256;
130
131 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
132
133 /*
134 * Interface to generic destination cache.
135 */
136
137 INDIRECT_CALLABLE_SCOPE
138 struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
139 static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
140 INDIRECT_CALLABLE_SCOPE
141 unsigned int ipv4_mtu(const struct dst_entry *dst);
142 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
143 static void ipv4_link_failure(struct sk_buff *skb);
144 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
145 struct sk_buff *skb, u32 mtu,
146 bool confirm_neigh);
147 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
148 struct sk_buff *skb);
149 static void ipv4_dst_destroy(struct dst_entry *dst);
150
ipv4_cow_metrics(struct dst_entry * dst,unsigned long old)151 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
152 {
153 WARN_ON(1);
154 return NULL;
155 }
156
157 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
158 struct sk_buff *skb,
159 const void *daddr);
160 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
161
162 static struct dst_ops ipv4_dst_ops = {
163 .family = AF_INET,
164 .check = ipv4_dst_check,
165 .default_advmss = ipv4_default_advmss,
166 .mtu = ipv4_mtu,
167 .cow_metrics = ipv4_cow_metrics,
168 .destroy = ipv4_dst_destroy,
169 .negative_advice = ipv4_negative_advice,
170 .link_failure = ipv4_link_failure,
171 .update_pmtu = ip_rt_update_pmtu,
172 .redirect = ip_do_redirect,
173 .local_out = __ip_local_out,
174 .neigh_lookup = ipv4_neigh_lookup,
175 .confirm_neigh = ipv4_confirm_neigh,
176 };
177
178 #define ECN_OR_COST(class) TC_PRIO_##class
179
180 const __u8 ip_tos2prio[16] = {
181 TC_PRIO_BESTEFFORT,
182 ECN_OR_COST(BESTEFFORT),
183 TC_PRIO_BESTEFFORT,
184 ECN_OR_COST(BESTEFFORT),
185 TC_PRIO_BULK,
186 ECN_OR_COST(BULK),
187 TC_PRIO_BULK,
188 ECN_OR_COST(BULK),
189 TC_PRIO_INTERACTIVE,
190 ECN_OR_COST(INTERACTIVE),
191 TC_PRIO_INTERACTIVE,
192 ECN_OR_COST(INTERACTIVE),
193 TC_PRIO_INTERACTIVE_BULK,
194 ECN_OR_COST(INTERACTIVE_BULK),
195 TC_PRIO_INTERACTIVE_BULK,
196 ECN_OR_COST(INTERACTIVE_BULK)
197 };
198 EXPORT_SYMBOL(ip_tos2prio);
199
200 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
201 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
202
203 #ifdef CONFIG_PROC_FS
rt_cache_seq_start(struct seq_file * seq,loff_t * pos)204 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
205 {
206 if (*pos)
207 return NULL;
208 return SEQ_START_TOKEN;
209 }
210
rt_cache_seq_next(struct seq_file * seq,void * v,loff_t * pos)211 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
212 {
213 ++*pos;
214 return NULL;
215 }
216
rt_cache_seq_stop(struct seq_file * seq,void * v)217 static void rt_cache_seq_stop(struct seq_file *seq, void *v)
218 {
219 }
220
rt_cache_seq_show(struct seq_file * seq,void * v)221 static int rt_cache_seq_show(struct seq_file *seq, void *v)
222 {
223 if (v == SEQ_START_TOKEN)
224 seq_printf(seq, "%-127s\n",
225 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
226 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
227 "HHUptod\tSpecDst");
228 return 0;
229 }
230
231 static const struct seq_operations rt_cache_seq_ops = {
232 .start = rt_cache_seq_start,
233 .next = rt_cache_seq_next,
234 .stop = rt_cache_seq_stop,
235 .show = rt_cache_seq_show,
236 };
237
rt_cpu_seq_start(struct seq_file * seq,loff_t * pos)238 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
239 {
240 int cpu;
241
242 if (*pos == 0)
243 return SEQ_START_TOKEN;
244
245 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
246 if (!cpu_possible(cpu))
247 continue;
248 *pos = cpu+1;
249 return &per_cpu(rt_cache_stat, cpu);
250 }
251 return NULL;
252 }
253
rt_cpu_seq_next(struct seq_file * seq,void * v,loff_t * pos)254 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
255 {
256 int cpu;
257
258 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
259 if (!cpu_possible(cpu))
260 continue;
261 *pos = cpu+1;
262 return &per_cpu(rt_cache_stat, cpu);
263 }
264 (*pos)++;
265 return NULL;
266
267 }
268
rt_cpu_seq_stop(struct seq_file * seq,void * v)269 static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
270 {
271
272 }
273
rt_cpu_seq_show(struct seq_file * seq,void * v)274 static int rt_cpu_seq_show(struct seq_file *seq, void *v)
275 {
276 struct rt_cache_stat *st = v;
277
278 if (v == SEQ_START_TOKEN) {
279 seq_puts(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
280 return 0;
281 }
282
283 seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x "
284 "%08x %08x %08x %08x %08x %08x "
285 "%08x %08x %08x %08x\n",
286 dst_entries_get_slow(&ipv4_dst_ops),
287 0, /* st->in_hit */
288 st->in_slow_tot,
289 st->in_slow_mc,
290 st->in_no_route,
291 st->in_brd,
292 st->in_martian_dst,
293 st->in_martian_src,
294
295 0, /* st->out_hit */
296 st->out_slow_tot,
297 st->out_slow_mc,
298
299 0, /* st->gc_total */
300 0, /* st->gc_ignored */
301 0, /* st->gc_goal_miss */
302 0, /* st->gc_dst_overflow */
303 0, /* st->in_hlist_search */
304 0 /* st->out_hlist_search */
305 );
306 return 0;
307 }
308
309 static const struct seq_operations rt_cpu_seq_ops = {
310 .start = rt_cpu_seq_start,
311 .next = rt_cpu_seq_next,
312 .stop = rt_cpu_seq_stop,
313 .show = rt_cpu_seq_show,
314 };
315
316 #ifdef CONFIG_IP_ROUTE_CLASSID
rt_acct_proc_show(struct seq_file * m,void * v)317 static int rt_acct_proc_show(struct seq_file *m, void *v)
318 {
319 struct ip_rt_acct *dst, *src;
320 unsigned int i, j;
321
322 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
323 if (!dst)
324 return -ENOMEM;
325
326 for_each_possible_cpu(i) {
327 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
328 for (j = 0; j < 256; j++) {
329 dst[j].o_bytes += src[j].o_bytes;
330 dst[j].o_packets += src[j].o_packets;
331 dst[j].i_bytes += src[j].i_bytes;
332 dst[j].i_packets += src[j].i_packets;
333 }
334 }
335
336 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct));
337 kfree(dst);
338 return 0;
339 }
340 #endif
341
ip_rt_do_proc_init(struct net * net)342 static int __net_init ip_rt_do_proc_init(struct net *net)
343 {
344 struct proc_dir_entry *pde;
345
346 pde = proc_create_seq("rt_cache", 0444, net->proc_net,
347 &rt_cache_seq_ops);
348 if (!pde)
349 goto err1;
350
351 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
352 &rt_cpu_seq_ops);
353 if (!pde)
354 goto err2;
355
356 #ifdef CONFIG_IP_ROUTE_CLASSID
357 pde = proc_create_single("rt_acct", 0, net->proc_net,
358 rt_acct_proc_show);
359 if (!pde)
360 goto err3;
361 #endif
362 return 0;
363
364 #ifdef CONFIG_IP_ROUTE_CLASSID
365 err3:
366 remove_proc_entry("rt_cache", net->proc_net_stat);
367 #endif
368 err2:
369 remove_proc_entry("rt_cache", net->proc_net);
370 err1:
371 return -ENOMEM;
372 }
373
ip_rt_do_proc_exit(struct net * net)374 static void __net_exit ip_rt_do_proc_exit(struct net *net)
375 {
376 remove_proc_entry("rt_cache", net->proc_net_stat);
377 remove_proc_entry("rt_cache", net->proc_net);
378 #ifdef CONFIG_IP_ROUTE_CLASSID
379 remove_proc_entry("rt_acct", net->proc_net);
380 #endif
381 }
382
383 static struct pernet_operations ip_rt_proc_ops __net_initdata = {
384 .init = ip_rt_do_proc_init,
385 .exit = ip_rt_do_proc_exit,
386 };
387
ip_rt_proc_init(void)388 static int __init ip_rt_proc_init(void)
389 {
390 return register_pernet_subsys(&ip_rt_proc_ops);
391 }
392
393 #else
ip_rt_proc_init(void)394 static inline int ip_rt_proc_init(void)
395 {
396 return 0;
397 }
398 #endif /* CONFIG_PROC_FS */
399
rt_is_expired(const struct rtable * rth)400 static inline bool rt_is_expired(const struct rtable *rth)
401 {
402 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev));
403 }
404
rt_cache_flush(struct net * net)405 void rt_cache_flush(struct net *net)
406 {
407 rt_genid_bump_ipv4(net);
408 }
409
ipv4_neigh_lookup(const struct dst_entry * dst,struct sk_buff * skb,const void * daddr)410 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
411 struct sk_buff *skb,
412 const void *daddr)
413 {
414 const struct rtable *rt = container_of(dst, struct rtable, dst);
415 struct net_device *dev = dst->dev;
416 struct neighbour *n;
417
418 rcu_read_lock_bh();
419
420 if (likely(rt->rt_gw_family == AF_INET)) {
421 n = ip_neigh_gw4(dev, rt->rt_gw4);
422 } else if (rt->rt_gw_family == AF_INET6) {
423 n = ip_neigh_gw6(dev, &rt->rt_gw6);
424 } else {
425 __be32 pkey;
426
427 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
428 n = ip_neigh_gw4(dev, pkey);
429 }
430
431 if (!IS_ERR(n) && !refcount_inc_not_zero(&n->refcnt))
432 n = NULL;
433
434 rcu_read_unlock_bh();
435
436 return n;
437 }
438
ipv4_confirm_neigh(const struct dst_entry * dst,const void * daddr)439 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
440 {
441 const struct rtable *rt = container_of(dst, struct rtable, dst);
442 struct net_device *dev = dst->dev;
443 const __be32 *pkey = daddr;
444
445 if (rt->rt_gw_family == AF_INET) {
446 pkey = (const __be32 *)&rt->rt_gw4;
447 } else if (rt->rt_gw_family == AF_INET6) {
448 return __ipv6_confirm_neigh_stub(dev, &rt->rt_gw6);
449 } else if (!daddr ||
450 (rt->rt_flags &
451 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
452 return;
453 }
454 __ipv4_confirm_neigh(dev, *(__force u32 *)pkey);
455 }
456
457 /* Hash tables of size 2048..262144 depending on RAM size.
458 * Each bucket uses 8 bytes.
459 */
460 static u32 ip_idents_mask __read_mostly;
461 static atomic_t *ip_idents __read_mostly;
462 static u32 *ip_tstamps __read_mostly;
463
464 /* In order to protect privacy, we add a perturbation to identifiers
465 * if one generator is seldom used. This makes hard for an attacker
466 * to infer how many packets were sent between two points in time.
467 */
ip_idents_reserve(u32 hash,int segs)468 u32 ip_idents_reserve(u32 hash, int segs)
469 {
470 u32 bucket, old, now = (u32)jiffies;
471 atomic_t *p_id;
472 u32 *p_tstamp;
473 u32 delta = 0;
474
475 bucket = hash & ip_idents_mask;
476 p_tstamp = ip_tstamps + bucket;
477 p_id = ip_idents + bucket;
478 old = READ_ONCE(*p_tstamp);
479
480 if (old != now && cmpxchg(p_tstamp, old, now) == old)
481 delta = prandom_u32_max(now - old);
482
483 /* If UBSAN reports an error there, please make sure your compiler
484 * supports -fno-strict-overflow before reporting it that was a bug
485 * in UBSAN, and it has been fixed in GCC-8.
486 */
487 return atomic_add_return(segs + delta, p_id) - segs;
488 }
489 EXPORT_SYMBOL(ip_idents_reserve);
490
__ip_select_ident(struct net * net,struct iphdr * iph,int segs)491 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
492 {
493 u32 hash, id;
494
495 /* Note the following code is not safe, but this is okay. */
496 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
497 get_random_bytes(&net->ipv4.ip_id_key,
498 sizeof(net->ipv4.ip_id_key));
499
500 hash = siphash_3u32((__force u32)iph->daddr,
501 (__force u32)iph->saddr,
502 iph->protocol,
503 &net->ipv4.ip_id_key);
504 id = ip_idents_reserve(hash, segs);
505 iph->id = htons(id);
506 }
507 EXPORT_SYMBOL(__ip_select_ident);
508
ip_rt_fix_tos(struct flowi4 * fl4)509 static void ip_rt_fix_tos(struct flowi4 *fl4)
510 {
511 __u8 tos = RT_FL_TOS(fl4);
512
513 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
514 fl4->flowi4_scope = tos & RTO_ONLINK ?
515 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE;
516 }
517
__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)518 static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
519 const struct sock *sk,
520 const struct iphdr *iph,
521 int oif, u8 tos,
522 u8 prot, u32 mark, int flow_flags)
523 {
524 if (sk) {
525 const struct inet_sock *inet = inet_sk(sk);
526
527 oif = sk->sk_bound_dev_if;
528 mark = sk->sk_mark;
529 tos = RT_CONN_FLAGS(sk);
530 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;
531 }
532 flowi4_init_output(fl4, oif, mark, tos,
533 RT_SCOPE_UNIVERSE, prot,
534 flow_flags,
535 iph->daddr, iph->saddr, 0, 0,
536 sock_net_uid(net, sk));
537 }
538
build_skb_flow_key(struct flowi4 * fl4,const struct sk_buff * skb,const struct sock * sk)539 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
540 const struct sock *sk)
541 {
542 const struct net *net = dev_net(skb->dev);
543 const struct iphdr *iph = ip_hdr(skb);
544 int oif = skb->dev->ifindex;
545 u8 tos = RT_TOS(iph->tos);
546 u8 prot = iph->protocol;
547 u32 mark = skb->mark;
548
549 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);
550 }
551
build_sk_flow_key(struct flowi4 * fl4,const struct sock * sk)552 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
553 {
554 const struct inet_sock *inet = inet_sk(sk);
555 const struct ip_options_rcu *inet_opt;
556 __be32 daddr = inet->inet_daddr;
557
558 rcu_read_lock();
559 inet_opt = rcu_dereference(inet->inet_opt);
560 if (inet_opt && inet_opt->opt.srr)
561 daddr = inet_opt->opt.faddr;
562 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,
563 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
564 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
565 inet_sk_flowi_flags(sk),
566 daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
567 rcu_read_unlock();
568 }
569
ip_rt_build_flow_key(struct flowi4 * fl4,const struct sock * sk,const struct sk_buff * skb)570 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
571 const struct sk_buff *skb)
572 {
573 if (skb)
574 build_skb_flow_key(fl4, skb, sk);
575 else
576 build_sk_flow_key(fl4, sk);
577 }
578
579 static DEFINE_SPINLOCK(fnhe_lock);
580
fnhe_flush_routes(struct fib_nh_exception * fnhe)581 static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
582 {
583 struct rtable *rt;
584
585 rt = rcu_dereference(fnhe->fnhe_rth_input);
586 if (rt) {
587 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
588 dst_dev_put(&rt->dst);
589 dst_release(&rt->dst);
590 }
591 rt = rcu_dereference(fnhe->fnhe_rth_output);
592 if (rt) {
593 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
594 dst_dev_put(&rt->dst);
595 dst_release(&rt->dst);
596 }
597 }
598
fnhe_remove_oldest(struct fnhe_hash_bucket * hash)599 static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
600 {
601 struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
602 struct fib_nh_exception *fnhe, *oldest = NULL;
603
604 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
605 fnhe = rcu_dereference_protected(*fnhe_p,
606 lockdep_is_held(&fnhe_lock));
607 if (!fnhe)
608 break;
609 if (!oldest ||
610 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
611 oldest = fnhe;
612 oldest_p = fnhe_p;
613 }
614 }
615 fnhe_flush_routes(oldest);
616 *oldest_p = oldest->fnhe_next;
617 kfree_rcu(oldest, rcu);
618 }
619
fnhe_hashfun(__be32 daddr)620 static u32 fnhe_hashfun(__be32 daddr)
621 {
622 static siphash_key_t fnhe_hash_key __read_mostly;
623 u64 hval;
624
625 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
626 hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key);
627 return hash_64(hval, FNHE_HASH_SHIFT);
628 }
629
fill_route_from_fnhe(struct rtable * rt,struct fib_nh_exception * fnhe)630 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
631 {
632 rt->rt_pmtu = fnhe->fnhe_pmtu;
633 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
634 rt->dst.expires = fnhe->fnhe_expires;
635
636 if (fnhe->fnhe_gw) {
637 rt->rt_flags |= RTCF_REDIRECTED;
638 rt->rt_uses_gateway = 1;
639 rt->rt_gw_family = AF_INET;
640 rt->rt_gw4 = fnhe->fnhe_gw;
641 }
642 }
643
update_or_create_fnhe(struct fib_nh_common * nhc,__be32 daddr,__be32 gw,u32 pmtu,bool lock,unsigned long expires)644 static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
645 __be32 gw, u32 pmtu, bool lock,
646 unsigned long expires)
647 {
648 struct fnhe_hash_bucket *hash;
649 struct fib_nh_exception *fnhe;
650 struct rtable *rt;
651 u32 genid, hval;
652 unsigned int i;
653 int depth;
654
655 genid = fnhe_genid(dev_net(nhc->nhc_dev));
656 hval = fnhe_hashfun(daddr);
657
658 spin_lock_bh(&fnhe_lock);
659
660 hash = rcu_dereference(nhc->nhc_exceptions);
661 if (!hash) {
662 hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
663 if (!hash)
664 goto out_unlock;
665 rcu_assign_pointer(nhc->nhc_exceptions, hash);
666 }
667
668 hash += hval;
669
670 depth = 0;
671 for (fnhe = rcu_dereference(hash->chain); fnhe;
672 fnhe = rcu_dereference(fnhe->fnhe_next)) {
673 if (fnhe->fnhe_daddr == daddr)
674 break;
675 depth++;
676 }
677
678 if (fnhe) {
679 if (fnhe->fnhe_genid != genid)
680 fnhe->fnhe_genid = genid;
681 if (gw)
682 fnhe->fnhe_gw = gw;
683 if (pmtu) {
684 fnhe->fnhe_pmtu = pmtu;
685 fnhe->fnhe_mtu_locked = lock;
686 }
687 fnhe->fnhe_expires = max(1UL, expires);
688 /* Update all cached dsts too */
689 rt = rcu_dereference(fnhe->fnhe_rth_input);
690 if (rt)
691 fill_route_from_fnhe(rt, fnhe);
692 rt = rcu_dereference(fnhe->fnhe_rth_output);
693 if (rt)
694 fill_route_from_fnhe(rt, fnhe);
695 } else {
696 /* Randomize max depth to avoid some side channels attacks. */
697 int max_depth = FNHE_RECLAIM_DEPTH +
698 prandom_u32_max(FNHE_RECLAIM_DEPTH);
699
700 while (depth > max_depth) {
701 fnhe_remove_oldest(hash);
702 depth--;
703 }
704
705 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
706 if (!fnhe)
707 goto out_unlock;
708
709 fnhe->fnhe_next = hash->chain;
710
711 fnhe->fnhe_genid = genid;
712 fnhe->fnhe_daddr = daddr;
713 fnhe->fnhe_gw = gw;
714 fnhe->fnhe_pmtu = pmtu;
715 fnhe->fnhe_mtu_locked = lock;
716 fnhe->fnhe_expires = max(1UL, expires);
717
718 rcu_assign_pointer(hash->chain, fnhe);
719
720 /* Exception created; mark the cached routes for the nexthop
721 * stale, so anyone caching it rechecks if this exception
722 * applies to them.
723 */
724 rt = rcu_dereference(nhc->nhc_rth_input);
725 if (rt)
726 rt->dst.obsolete = DST_OBSOLETE_KILL;
727
728 for_each_possible_cpu(i) {
729 struct rtable __rcu **prt;
730
731 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
732 rt = rcu_dereference(*prt);
733 if (rt)
734 rt->dst.obsolete = DST_OBSOLETE_KILL;
735 }
736 }
737
738 fnhe->fnhe_stamp = jiffies;
739
740 out_unlock:
741 spin_unlock_bh(&fnhe_lock);
742 }
743
__ip_do_redirect(struct rtable * rt,struct sk_buff * skb,struct flowi4 * fl4,bool kill_route)744 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
745 bool kill_route)
746 {
747 __be32 new_gw = icmp_hdr(skb)->un.gateway;
748 __be32 old_gw = ip_hdr(skb)->saddr;
749 struct net_device *dev = skb->dev;
750 struct in_device *in_dev;
751 struct fib_result res;
752 struct neighbour *n;
753 struct net *net;
754
755 switch (icmp_hdr(skb)->code & 7) {
756 case ICMP_REDIR_NET:
757 case ICMP_REDIR_NETTOS:
758 case ICMP_REDIR_HOST:
759 case ICMP_REDIR_HOSTTOS:
760 break;
761
762 default:
763 return;
764 }
765
766 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
767 return;
768
769 in_dev = __in_dev_get_rcu(dev);
770 if (!in_dev)
771 return;
772
773 net = dev_net(dev);
774 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
775 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
776 ipv4_is_zeronet(new_gw))
777 goto reject_redirect;
778
779 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
780 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
781 goto reject_redirect;
782 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev))
783 goto reject_redirect;
784 } else {
785 if (inet_addr_type(net, new_gw) != RTN_UNICAST)
786 goto reject_redirect;
787 }
788
789 n = __ipv4_neigh_lookup(rt->dst.dev, (__force u32)new_gw);
790 if (!n)
791 n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
792 if (!IS_ERR(n)) {
793 if (!(n->nud_state & NUD_VALID)) {
794 neigh_event_send(n, NULL);
795 } else {
796 if (fib_lookup(net, fl4, &res, 0) == 0) {
797 struct fib_nh_common *nhc;
798
799 fib_select_path(net, &res, fl4, skb);
800 nhc = FIB_RES_NHC(res);
801 update_or_create_fnhe(nhc, 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_rt_fix_tos(&fl4);
844 __ip_do_redirect(rt, skb, &fl4, true);
845 }
846
ipv4_negative_advice(struct dst_entry * dst)847 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
848 {
849 struct rtable *rt = (struct rtable *)dst;
850 struct dst_entry *ret = dst;
851
852 if (rt) {
853 if (dst->obsolete > 0) {
854 ip_rt_put(rt);
855 ret = NULL;
856 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
857 rt->dst.expires) {
858 ip_rt_put(rt);
859 ret = NULL;
860 }
861 }
862 return ret;
863 }
864
865 /*
866 * Algorithm:
867 * 1. The first ip_rt_redirect_number redirects are sent
868 * with exponential backoff, then we stop sending them at all,
869 * assuming that the host ignores our redirects.
870 * 2. If we did not see packets requiring redirects
871 * during ip_rt_redirect_silence, we assume that the host
872 * forgot redirected route and start to send redirects again.
873 *
874 * This algorithm is much cheaper and more intelligent than dumb load limiting
875 * in icmp.c.
876 *
877 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
878 * and "frag. need" (breaks PMTU discovery) in icmp.c.
879 */
880
ip_rt_send_redirect(struct sk_buff * skb)881 void ip_rt_send_redirect(struct sk_buff *skb)
882 {
883 struct rtable *rt = skb_rtable(skb);
884 struct in_device *in_dev;
885 struct inet_peer *peer;
886 struct net *net;
887 int log_martians;
888 int vif;
889
890 rcu_read_lock();
891 in_dev = __in_dev_get_rcu(rt->dst.dev);
892 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
893 rcu_read_unlock();
894 return;
895 }
896 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
897 vif = l3mdev_master_ifindex_rcu(rt->dst.dev);
898 rcu_read_unlock();
899
900 net = dev_net(rt->dst.dev);
901 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1);
902 if (!peer) {
903 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
904 rt_nexthop(rt, ip_hdr(skb)->daddr));
905 return;
906 }
907
908 /* No redirected packets during ip_rt_redirect_silence;
909 * reset the algorithm.
910 */
911 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
912 peer->rate_tokens = 0;
913 peer->n_redirects = 0;
914 }
915
916 /* Too many ignored redirects; do not send anything
917 * set dst.rate_last to the last seen redirected packet.
918 */
919 if (peer->n_redirects >= ip_rt_redirect_number) {
920 peer->rate_last = jiffies;
921 goto out_put_peer;
922 }
923
924 /* Check for load limit; set rate_last to the latest sent
925 * redirect.
926 */
927 if (peer->n_redirects == 0 ||
928 time_after(jiffies,
929 (peer->rate_last +
930 (ip_rt_redirect_load << peer->n_redirects)))) {
931 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr);
932
933 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
934 peer->rate_last = jiffies;
935 ++peer->n_redirects;
936 #ifdef CONFIG_IP_ROUTE_VERBOSE
937 if (log_martians &&
938 peer->n_redirects == ip_rt_redirect_number)
939 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
940 &ip_hdr(skb)->saddr, inet_iif(skb),
941 &ip_hdr(skb)->daddr, &gw);
942 #endif
943 }
944 out_put_peer:
945 inet_putpeer(peer);
946 }
947
ip_error(struct sk_buff * skb)948 static int ip_error(struct sk_buff *skb)
949 {
950 struct rtable *rt = skb_rtable(skb);
951 struct net_device *dev = skb->dev;
952 struct in_device *in_dev;
953 struct inet_peer *peer;
954 unsigned long now;
955 struct net *net;
956 bool send;
957 int code;
958
959 if (netif_is_l3_master(skb->dev)) {
960 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
961 if (!dev)
962 goto out;
963 }
964
965 in_dev = __in_dev_get_rcu(dev);
966
967 /* IP on this device is disabled. */
968 if (!in_dev)
969 goto out;
970
971 net = dev_net(rt->dst.dev);
972 if (!IN_DEV_FORWARD(in_dev)) {
973 switch (rt->dst.error) {
974 case EHOSTUNREACH:
975 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
976 break;
977
978 case ENETUNREACH:
979 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
980 break;
981 }
982 goto out;
983 }
984
985 switch (rt->dst.error) {
986 case EINVAL:
987 default:
988 goto out;
989 case EHOSTUNREACH:
990 code = ICMP_HOST_UNREACH;
991 break;
992 case ENETUNREACH:
993 code = ICMP_NET_UNREACH;
994 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
995 break;
996 case EACCES:
997 code = ICMP_PKT_FILTERED;
998 break;
999 }
1000
1001 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr,
1002 l3mdev_master_ifindex(skb->dev), 1);
1003
1004 send = true;
1005 if (peer) {
1006 now = jiffies;
1007 peer->rate_tokens += now - peer->rate_last;
1008 if (peer->rate_tokens > ip_rt_error_burst)
1009 peer->rate_tokens = ip_rt_error_burst;
1010 peer->rate_last = now;
1011 if (peer->rate_tokens >= ip_rt_error_cost)
1012 peer->rate_tokens -= ip_rt_error_cost;
1013 else
1014 send = false;
1015 inet_putpeer(peer);
1016 }
1017 if (send)
1018 icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
1019
1020 out: kfree_skb(skb);
1021 return 0;
1022 }
1023
__ip_rt_update_pmtu(struct rtable * rt,struct flowi4 * fl4,u32 mtu)1024 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1025 {
1026 struct dst_entry *dst = &rt->dst;
1027 struct net *net = dev_net(dst->dev);
1028 struct fib_result res;
1029 bool lock = false;
1030 u32 old_mtu;
1031
1032 if (ip_mtu_locked(dst))
1033 return;
1034
1035 old_mtu = ipv4_mtu(dst);
1036 if (old_mtu < mtu)
1037 return;
1038
1039 if (mtu < ip_rt_min_pmtu) {
1040 lock = true;
1041 mtu = min(old_mtu, ip_rt_min_pmtu);
1042 }
1043
1044 if (rt->rt_pmtu == mtu && !lock &&
1045 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2))
1046 return;
1047
1048 rcu_read_lock();
1049 if (fib_lookup(net, fl4, &res, 0) == 0) {
1050 struct fib_nh_common *nhc;
1051
1052 fib_select_path(net, &res, fl4, NULL);
1053 nhc = FIB_RES_NHC(res);
1054 update_or_create_fnhe(nhc, fl4->daddr, 0, mtu, lock,
1055 jiffies + ip_rt_mtu_expires);
1056 }
1057 rcu_read_unlock();
1058 }
1059
ip_rt_update_pmtu(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb,u32 mtu,bool confirm_neigh)1060 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1061 struct sk_buff *skb, u32 mtu,
1062 bool confirm_neigh)
1063 {
1064 struct rtable *rt = (struct rtable *) dst;
1065 struct flowi4 fl4;
1066
1067 ip_rt_build_flow_key(&fl4, sk, skb);
1068 ip_rt_fix_tos(&fl4);
1069
1070 /* Don't make lookup fail for bridged encapsulations */
1071 if (skb && netif_is_any_bridge_port(skb->dev))
1072 fl4.flowi4_oif = 0;
1073
1074 __ip_rt_update_pmtu(rt, &fl4, mtu);
1075 }
1076
ipv4_update_pmtu(struct sk_buff * skb,struct net * net,u32 mtu,int oif,u8 protocol)1077 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1078 int oif, u8 protocol)
1079 {
1080 const struct iphdr *iph = (const struct iphdr *)skb->data;
1081 struct flowi4 fl4;
1082 struct rtable *rt;
1083 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1084
1085 __build_flow_key(net, &fl4, NULL, iph, oif,
1086 RT_TOS(iph->tos), protocol, mark, 0);
1087 rt = __ip_route_output_key(net, &fl4);
1088 if (!IS_ERR(rt)) {
1089 __ip_rt_update_pmtu(rt, &fl4, mtu);
1090 ip_rt_put(rt);
1091 }
1092 }
1093 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1094
__ipv4_sk_update_pmtu(struct sk_buff * skb,struct sock * sk,u32 mtu)1095 static 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
1101 __build_flow_key(sock_net(sk), &fl4, sk, iph, 0, 0, 0, 0, 0);
1102
1103 if (!fl4.flowi4_mark)
1104 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1105
1106 rt = __ip_route_output_key(sock_net(sk), &fl4);
1107 if (!IS_ERR(rt)) {
1108 __ip_rt_update_pmtu(rt, &fl4, mtu);
1109 ip_rt_put(rt);
1110 }
1111 }
1112
ipv4_sk_update_pmtu(struct sk_buff * skb,struct sock * sk,u32 mtu)1113 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1114 {
1115 const struct iphdr *iph = (const struct iphdr *)skb->data;
1116 struct flowi4 fl4;
1117 struct rtable *rt;
1118 struct dst_entry *odst = NULL;
1119 bool new = false;
1120 struct net *net = sock_net(sk);
1121
1122 bh_lock_sock(sk);
1123
1124 if (!ip_sk_accept_pmtu(sk))
1125 goto out;
1126
1127 odst = sk_dst_get(sk);
1128
1129 if (sock_owned_by_user(sk) || !odst) {
1130 __ipv4_sk_update_pmtu(skb, sk, mtu);
1131 goto out;
1132 }
1133
1134 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1135
1136 rt = (struct rtable *)odst;
1137 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1138 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1139 if (IS_ERR(rt))
1140 goto out;
1141
1142 new = true;
1143 } else {
1144 ip_rt_fix_tos(&fl4);
1145 }
1146
1147 __ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu);
1148
1149 if (!dst_check(&rt->dst, 0)) {
1150 if (new)
1151 dst_release(&rt->dst);
1152
1153 rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
1154 if (IS_ERR(rt))
1155 goto out;
1156
1157 new = true;
1158 }
1159
1160 if (new)
1161 sk_dst_set(sk, &rt->dst);
1162
1163 out:
1164 bh_unlock_sock(sk);
1165 dst_release(odst);
1166 }
1167 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1168
ipv4_redirect(struct sk_buff * skb,struct net * net,int oif,u8 protocol)1169 void ipv4_redirect(struct sk_buff *skb, struct net *net,
1170 int oif, u8 protocol)
1171 {
1172 const struct iphdr *iph = (const struct iphdr *)skb->data;
1173 struct flowi4 fl4;
1174 struct rtable *rt;
1175
1176 __build_flow_key(net, &fl4, NULL, iph, oif,
1177 RT_TOS(iph->tos), protocol, 0, 0);
1178 rt = __ip_route_output_key(net, &fl4);
1179 if (!IS_ERR(rt)) {
1180 __ip_do_redirect(rt, skb, &fl4, false);
1181 ip_rt_put(rt);
1182 }
1183 }
1184 EXPORT_SYMBOL_GPL(ipv4_redirect);
1185
ipv4_sk_redirect(struct sk_buff * skb,struct sock * sk)1186 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1187 {
1188 const struct iphdr *iph = (const struct iphdr *)skb->data;
1189 struct flowi4 fl4;
1190 struct rtable *rt;
1191 struct net *net = sock_net(sk);
1192
1193 __build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
1194 rt = __ip_route_output_key(net, &fl4);
1195 if (!IS_ERR(rt)) {
1196 __ip_do_redirect(rt, skb, &fl4, false);
1197 ip_rt_put(rt);
1198 }
1199 }
1200 EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1201
ipv4_dst_check(struct dst_entry * dst,u32 cookie)1202 INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1203 u32 cookie)
1204 {
1205 struct rtable *rt = (struct rtable *) dst;
1206
1207 /* All IPV4 dsts are created with ->obsolete set to the value
1208 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1209 * into this function always.
1210 *
1211 * When a PMTU/redirect information update invalidates a route,
1212 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1213 * DST_OBSOLETE_DEAD.
1214 */
1215 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
1216 return NULL;
1217 return dst;
1218 }
1219 EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1220
ipv4_send_dest_unreach(struct sk_buff * skb)1221 static void ipv4_send_dest_unreach(struct sk_buff *skb)
1222 {
1223 struct net_device *dev;
1224 struct ip_options opt;
1225 int res;
1226
1227 /* Recompile ip options since IPCB may not be valid anymore.
1228 * Also check we have a reasonable ipv4 header.
1229 */
1230 if (!pskb_network_may_pull(skb, sizeof(struct iphdr)) ||
1231 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1232 return;
1233
1234 memset(&opt, 0, sizeof(opt));
1235 if (ip_hdr(skb)->ihl > 5) {
1236 if (!pskb_network_may_pull(skb, ip_hdr(skb)->ihl * 4))
1237 return;
1238 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1239
1240 rcu_read_lock();
1241 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
1242 res = __ip_options_compile(dev_net(dev), &opt, skb, NULL);
1243 rcu_read_unlock();
1244
1245 if (res)
1246 return;
1247 }
1248 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);
1249 }
1250
ipv4_link_failure(struct sk_buff * skb)1251 static void ipv4_link_failure(struct sk_buff *skb)
1252 {
1253 struct rtable *rt;
1254
1255 ipv4_send_dest_unreach(skb);
1256
1257 rt = skb_rtable(skb);
1258 if (rt)
1259 dst_set_expires(&rt->dst, 0);
1260 }
1261
ip_rt_bug(struct net * net,struct sock * sk,struct sk_buff * skb)1262 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1263 {
1264 pr_debug("%s: %pI4 -> %pI4, %s\n",
1265 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1266 skb->dev ? skb->dev->name : "?");
1267 kfree_skb(skb);
1268 WARN_ON(1);
1269 return 0;
1270 }
1271
1272 /*
1273 * We do not cache source address of outgoing interface,
1274 * because it is used only by IP RR, TS and SRR options,
1275 * so that it out of fast path.
1276 *
1277 * BTW remember: "addr" is allowed to be not aligned
1278 * in IP options!
1279 */
1280
ip_rt_get_source(u8 * addr,struct sk_buff * skb,struct rtable * rt)1281 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1282 {
1283 __be32 src;
1284
1285 if (rt_is_output_route(rt))
1286 src = ip_hdr(skb)->saddr;
1287 else {
1288 struct fib_result res;
1289 struct iphdr *iph = ip_hdr(skb);
1290 struct flowi4 fl4 = {
1291 .daddr = iph->daddr,
1292 .saddr = iph->saddr,
1293 .flowi4_tos = RT_TOS(iph->tos),
1294 .flowi4_oif = rt->dst.dev->ifindex,
1295 .flowi4_iif = skb->dev->ifindex,
1296 .flowi4_mark = skb->mark,
1297 };
1298
1299 rcu_read_lock();
1300 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0)
1301 src = fib_result_prefsrc(dev_net(rt->dst.dev), &res);
1302 else
1303 src = inet_select_addr(rt->dst.dev,
1304 rt_nexthop(rt, iph->daddr),
1305 RT_SCOPE_UNIVERSE);
1306 rcu_read_unlock();
1307 }
1308 memcpy(addr, &src, 4);
1309 }
1310
1311 #ifdef CONFIG_IP_ROUTE_CLASSID
set_class_tag(struct rtable * rt,u32 tag)1312 static void set_class_tag(struct rtable *rt, u32 tag)
1313 {
1314 if (!(rt->dst.tclassid & 0xFFFF))
1315 rt->dst.tclassid |= tag & 0xFFFF;
1316 if (!(rt->dst.tclassid & 0xFFFF0000))
1317 rt->dst.tclassid |= tag & 0xFFFF0000;
1318 }
1319 #endif
1320
ipv4_default_advmss(const struct dst_entry * dst)1321 static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1322 {
1323 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1324 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1325 ip_rt_min_advmss);
1326
1327 return min(advmss, IPV4_MAX_PMTU - header_size);
1328 }
1329
ipv4_mtu(const struct dst_entry * dst)1330 INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1331 {
1332 return ip_dst_mtu_maybe_forward(dst, false);
1333 }
1334 EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1335
ip_del_fnhe(struct fib_nh_common * nhc,__be32 daddr)1336 static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1337 {
1338 struct fnhe_hash_bucket *hash;
1339 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1340 u32 hval = fnhe_hashfun(daddr);
1341
1342 spin_lock_bh(&fnhe_lock);
1343
1344 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1345 lockdep_is_held(&fnhe_lock));
1346 hash += hval;
1347
1348 fnhe_p = &hash->chain;
1349 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1350 while (fnhe) {
1351 if (fnhe->fnhe_daddr == daddr) {
1352 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1353 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1354 /* set fnhe_daddr to 0 to ensure it won't bind with
1355 * new dsts in rt_bind_exception().
1356 */
1357 fnhe->fnhe_daddr = 0;
1358 fnhe_flush_routes(fnhe);
1359 kfree_rcu(fnhe, rcu);
1360 break;
1361 }
1362 fnhe_p = &fnhe->fnhe_next;
1363 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1364 lockdep_is_held(&fnhe_lock));
1365 }
1366
1367 spin_unlock_bh(&fnhe_lock);
1368 }
1369
find_exception(struct fib_nh_common * nhc,__be32 daddr)1370 static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1371 __be32 daddr)
1372 {
1373 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1374 struct fib_nh_exception *fnhe;
1375 u32 hval;
1376
1377 if (!hash)
1378 return NULL;
1379
1380 hval = fnhe_hashfun(daddr);
1381
1382 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1383 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1384 if (fnhe->fnhe_daddr == daddr) {
1385 if (fnhe->fnhe_expires &&
1386 time_after(jiffies, fnhe->fnhe_expires)) {
1387 ip_del_fnhe(nhc, daddr);
1388 break;
1389 }
1390 return fnhe;
1391 }
1392 }
1393 return NULL;
1394 }
1395
1396 /* MTU selection:
1397 * 1. mtu on route is locked - use it
1398 * 2. mtu from nexthop exception
1399 * 3. mtu from egress device
1400 */
1401
ip_mtu_from_fib_result(struct fib_result * res,__be32 daddr)1402 u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1403 {
1404 struct fib_nh_common *nhc = res->nhc;
1405 struct net_device *dev = nhc->nhc_dev;
1406 struct fib_info *fi = res->fi;
1407 u32 mtu = 0;
1408
1409 if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) ||
1410 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1411 mtu = fi->fib_mtu;
1412
1413 if (likely(!mtu)) {
1414 struct fib_nh_exception *fnhe;
1415
1416 fnhe = find_exception(nhc, daddr);
1417 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1418 mtu = fnhe->fnhe_pmtu;
1419 }
1420
1421 if (likely(!mtu))
1422 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1423
1424 return mtu - lwtunnel_headroom(nhc->nhc_lwtstate, mtu);
1425 }
1426
rt_bind_exception(struct rtable * rt,struct fib_nh_exception * fnhe,__be32 daddr,const bool do_cache)1427 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1428 __be32 daddr, const bool do_cache)
1429 {
1430 bool ret = false;
1431
1432 spin_lock_bh(&fnhe_lock);
1433
1434 if (daddr == fnhe->fnhe_daddr) {
1435 struct rtable __rcu **porig;
1436 struct rtable *orig;
1437 int genid = fnhe_genid(dev_net(rt->dst.dev));
1438
1439 if (rt_is_input_route(rt))
1440 porig = &fnhe->fnhe_rth_input;
1441 else
1442 porig = &fnhe->fnhe_rth_output;
1443 orig = rcu_dereference(*porig);
1444
1445 if (fnhe->fnhe_genid != genid) {
1446 fnhe->fnhe_genid = genid;
1447 fnhe->fnhe_gw = 0;
1448 fnhe->fnhe_pmtu = 0;
1449 fnhe->fnhe_expires = 0;
1450 fnhe->fnhe_mtu_locked = false;
1451 fnhe_flush_routes(fnhe);
1452 orig = NULL;
1453 }
1454 fill_route_from_fnhe(rt, fnhe);
1455 if (!rt->rt_gw4) {
1456 rt->rt_gw4 = daddr;
1457 rt->rt_gw_family = AF_INET;
1458 }
1459
1460 if (do_cache) {
1461 dst_hold(&rt->dst);
1462 rcu_assign_pointer(*porig, rt);
1463 if (orig) {
1464 dst_dev_put(&orig->dst);
1465 dst_release(&orig->dst);
1466 }
1467 ret = true;
1468 }
1469
1470 fnhe->fnhe_stamp = jiffies;
1471 }
1472 spin_unlock_bh(&fnhe_lock);
1473
1474 return ret;
1475 }
1476
rt_cache_route(struct fib_nh_common * nhc,struct rtable * rt)1477 static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1478 {
1479 struct rtable *orig, *prev, **p;
1480 bool ret = true;
1481
1482 if (rt_is_input_route(rt)) {
1483 p = (struct rtable **)&nhc->nhc_rth_input;
1484 } else {
1485 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1486 }
1487 orig = *p;
1488
1489 /* hold dst before doing cmpxchg() to avoid race condition
1490 * on this dst
1491 */
1492 dst_hold(&rt->dst);
1493 prev = cmpxchg(p, orig, rt);
1494 if (prev == orig) {
1495 if (orig) {
1496 rt_add_uncached_list(orig);
1497 dst_release(&orig->dst);
1498 }
1499 } else {
1500 dst_release(&rt->dst);
1501 ret = false;
1502 }
1503
1504 return ret;
1505 }
1506
1507 struct uncached_list {
1508 spinlock_t lock;
1509 struct list_head head;
1510 };
1511
1512 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1513
rt_add_uncached_list(struct rtable * rt)1514 void rt_add_uncached_list(struct rtable *rt)
1515 {
1516 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1517
1518 rt->rt_uncached_list = ul;
1519
1520 spin_lock_bh(&ul->lock);
1521 list_add_tail(&rt->rt_uncached, &ul->head);
1522 spin_unlock_bh(&ul->lock);
1523 }
1524
rt_del_uncached_list(struct rtable * rt)1525 void rt_del_uncached_list(struct rtable *rt)
1526 {
1527 if (!list_empty(&rt->rt_uncached)) {
1528 struct uncached_list *ul = rt->rt_uncached_list;
1529
1530 spin_lock_bh(&ul->lock);
1531 list_del(&rt->rt_uncached);
1532 spin_unlock_bh(&ul->lock);
1533 }
1534 }
1535
ipv4_dst_destroy(struct dst_entry * dst)1536 static void ipv4_dst_destroy(struct dst_entry *dst)
1537 {
1538 struct rtable *rt = (struct rtable *)dst;
1539
1540 ip_dst_metrics_put(dst);
1541 rt_del_uncached_list(rt);
1542 }
1543
rt_flush_dev(struct net_device * dev)1544 void rt_flush_dev(struct net_device *dev)
1545 {
1546 struct rtable *rt;
1547 int cpu;
1548
1549 for_each_possible_cpu(cpu) {
1550 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1551
1552 spin_lock_bh(&ul->lock);
1553 list_for_each_entry(rt, &ul->head, rt_uncached) {
1554 if (rt->dst.dev != dev)
1555 continue;
1556 rt->dst.dev = blackhole_netdev;
1557 dev_hold(rt->dst.dev);
1558 dev_put(dev);
1559 }
1560 spin_unlock_bh(&ul->lock);
1561 }
1562 }
1563
rt_cache_valid(const struct rtable * rt)1564 static bool rt_cache_valid(const struct rtable *rt)
1565 {
1566 return rt &&
1567 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1568 !rt_is_expired(rt);
1569 }
1570
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)1571 static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1572 const struct fib_result *res,
1573 struct fib_nh_exception *fnhe,
1574 struct fib_info *fi, u16 type, u32 itag,
1575 const bool do_cache)
1576 {
1577 bool cached = false;
1578
1579 if (fi) {
1580 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1581
1582 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1583 rt->rt_uses_gateway = 1;
1584 rt->rt_gw_family = nhc->nhc_gw_family;
1585 /* only INET and INET6 are supported */
1586 if (likely(nhc->nhc_gw_family == AF_INET))
1587 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1588 else
1589 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1590 }
1591
1592 ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
1593
1594 #ifdef CONFIG_IP_ROUTE_CLASSID
1595 if (nhc->nhc_family == AF_INET) {
1596 struct fib_nh *nh;
1597
1598 nh = container_of(nhc, struct fib_nh, nh_common);
1599 rt->dst.tclassid = nh->nh_tclassid;
1600 }
1601 #endif
1602 rt->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
1603 if (unlikely(fnhe))
1604 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1605 else if (do_cache)
1606 cached = rt_cache_route(nhc, rt);
1607 if (unlikely(!cached)) {
1608 /* Routes we intend to cache in nexthop exception or
1609 * FIB nexthop have the DST_NOCACHE bit clear.
1610 * However, if we are unsuccessful at storing this
1611 * route into the cache we really need to set it.
1612 */
1613 if (!rt->rt_gw4) {
1614 rt->rt_gw_family = AF_INET;
1615 rt->rt_gw4 = daddr;
1616 }
1617 rt_add_uncached_list(rt);
1618 }
1619 } else
1620 rt_add_uncached_list(rt);
1621
1622 #ifdef CONFIG_IP_ROUTE_CLASSID
1623 #ifdef CONFIG_IP_MULTIPLE_TABLES
1624 set_class_tag(rt, res->tclassid);
1625 #endif
1626 set_class_tag(rt, itag);
1627 #endif
1628 }
1629
rt_dst_alloc(struct net_device * dev,unsigned int flags,u16 type,bool nopolicy,bool noxfrm)1630 struct rtable *rt_dst_alloc(struct net_device *dev,
1631 unsigned int flags, u16 type,
1632 bool nopolicy, bool noxfrm)
1633 {
1634 struct rtable *rt;
1635
1636 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1637 (nopolicy ? DST_NOPOLICY : 0) |
1638 (noxfrm ? DST_NOXFRM : 0));
1639
1640 if (rt) {
1641 rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1642 rt->rt_flags = flags;
1643 rt->rt_type = type;
1644 rt->rt_is_input = 0;
1645 rt->rt_iif = 0;
1646 rt->rt_pmtu = 0;
1647 rt->rt_mtu_locked = 0;
1648 rt->rt_uses_gateway = 0;
1649 rt->rt_gw_family = 0;
1650 rt->rt_gw4 = 0;
1651 INIT_LIST_HEAD(&rt->rt_uncached);
1652
1653 rt->dst.output = ip_output;
1654 if (flags & RTCF_LOCAL)
1655 rt->dst.input = ip_local_deliver;
1656 }
1657
1658 return rt;
1659 }
1660 EXPORT_SYMBOL(rt_dst_alloc);
1661
rt_dst_clone(struct net_device * dev,struct rtable * rt)1662 struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1663 {
1664 struct rtable *new_rt;
1665
1666 new_rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,
1667 rt->dst.flags);
1668
1669 if (new_rt) {
1670 new_rt->rt_genid = rt_genid_ipv4(dev_net(dev));
1671 new_rt->rt_flags = rt->rt_flags;
1672 new_rt->rt_type = rt->rt_type;
1673 new_rt->rt_is_input = rt->rt_is_input;
1674 new_rt->rt_iif = rt->rt_iif;
1675 new_rt->rt_pmtu = rt->rt_pmtu;
1676 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1677 new_rt->rt_gw_family = rt->rt_gw_family;
1678 if (rt->rt_gw_family == AF_INET)
1679 new_rt->rt_gw4 = rt->rt_gw4;
1680 else if (rt->rt_gw_family == AF_INET6)
1681 new_rt->rt_gw6 = rt->rt_gw6;
1682 INIT_LIST_HEAD(&new_rt->rt_uncached);
1683
1684 new_rt->dst.input = rt->dst.input;
1685 new_rt->dst.output = rt->dst.output;
1686 new_rt->dst.error = rt->dst.error;
1687 new_rt->dst.lastuse = jiffies;
1688 new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
1689 }
1690 return new_rt;
1691 }
1692 EXPORT_SYMBOL(rt_dst_clone);
1693
1694 /* 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)1695 int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1696 u8 tos, struct net_device *dev,
1697 struct in_device *in_dev, u32 *itag)
1698 {
1699 int err;
1700
1701 /* Primary sanity checks. */
1702 if (!in_dev)
1703 return -EINVAL;
1704
1705 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
1706 skb->protocol != htons(ETH_P_IP))
1707 return -EINVAL;
1708
1709 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1710 return -EINVAL;
1711
1712 if (ipv4_is_zeronet(saddr)) {
1713 if (!ipv4_is_local_multicast(daddr) &&
1714 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1715 return -EINVAL;
1716 } else {
1717 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
1718 in_dev, itag);
1719 if (err < 0)
1720 return err;
1721 }
1722 return 0;
1723 }
1724
1725 /* called in rcu_read_lock() section */
ip_route_input_mc(struct sk_buff * skb,__be32 daddr,__be32 saddr,u8 tos,struct net_device * dev,int our)1726 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1727 u8 tos, struct net_device *dev, int our)
1728 {
1729 struct in_device *in_dev = __in_dev_get_rcu(dev);
1730 unsigned int flags = RTCF_MULTICAST;
1731 struct rtable *rth;
1732 bool no_policy;
1733 u32 itag = 0;
1734 int err;
1735
1736 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, &itag);
1737 if (err)
1738 return err;
1739
1740 if (our)
1741 flags |= RTCF_LOCAL;
1742
1743 no_policy = IN_DEV_ORCONF(in_dev, NOPOLICY);
1744 if (no_policy)
1745 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1746
1747 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1748 no_policy, false);
1749 if (!rth)
1750 return -ENOBUFS;
1751
1752 #ifdef CONFIG_IP_ROUTE_CLASSID
1753 rth->dst.tclassid = itag;
1754 #endif
1755 rth->dst.output = ip_rt_bug;
1756 rth->rt_is_input= 1;
1757
1758 #ifdef CONFIG_IP_MROUTE
1759 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev))
1760 rth->dst.input = ip_mr_input;
1761 #endif
1762 RT_CACHE_STAT_INC(in_slow_mc);
1763
1764 skb_dst_drop(skb);
1765 skb_dst_set(skb, &rth->dst);
1766 return 0;
1767 }
1768
1769
ip_handle_martian_source(struct net_device * dev,struct in_device * in_dev,struct sk_buff * skb,__be32 daddr,__be32 saddr)1770 static void ip_handle_martian_source(struct net_device *dev,
1771 struct in_device *in_dev,
1772 struct sk_buff *skb,
1773 __be32 daddr,
1774 __be32 saddr)
1775 {
1776 RT_CACHE_STAT_INC(in_martian_src);
1777 #ifdef CONFIG_IP_ROUTE_VERBOSE
1778 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1779 /*
1780 * RFC1812 recommendation, if source is martian,
1781 * the only hint is MAC header.
1782 */
1783 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1784 &daddr, &saddr, dev->name);
1785 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1786 print_hex_dump(KERN_WARNING, "ll header: ",
1787 DUMP_PREFIX_OFFSET, 16, 1,
1788 skb_mac_header(skb),
1789 dev->hard_header_len, false);
1790 }
1791 }
1792 #endif
1793 }
1794
1795 /* 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)1796 static int __mkroute_input(struct sk_buff *skb,
1797 const struct fib_result *res,
1798 struct in_device *in_dev,
1799 __be32 daddr, __be32 saddr, u32 tos)
1800 {
1801 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1802 struct net_device *dev = nhc->nhc_dev;
1803 struct fib_nh_exception *fnhe;
1804 struct rtable *rth;
1805 int err;
1806 struct in_device *out_dev;
1807 bool do_cache, no_policy;
1808 u32 itag = 0;
1809
1810 /* get a working reference to the output device */
1811 out_dev = __in_dev_get_rcu(dev);
1812 if (!out_dev) {
1813 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1814 return -EINVAL;
1815 }
1816
1817 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res),
1818 in_dev->dev, in_dev, &itag);
1819 if (err < 0) {
1820 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
1821 saddr);
1822
1823 goto cleanup;
1824 }
1825
1826 do_cache = res->fi && !itag;
1827 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1828 skb->protocol == htons(ETH_P_IP)) {
1829 __be32 gw;
1830
1831 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1832 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1833 inet_addr_onlink(out_dev, saddr, gw))
1834 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1835 }
1836
1837 if (skb->protocol != htons(ETH_P_IP)) {
1838 /* Not IP (i.e. ARP). Do not create route, if it is
1839 * invalid for proxy arp. DNAT routes are always valid.
1840 *
1841 * Proxy arp feature have been extended to allow, ARP
1842 * replies back to the same interface, to support
1843 * Private VLAN switch technologies. See arp.c.
1844 */
1845 if (out_dev == in_dev &&
1846 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1847 err = -EINVAL;
1848 goto cleanup;
1849 }
1850 }
1851
1852 no_policy = IN_DEV_ORCONF(in_dev, NOPOLICY);
1853 if (no_policy)
1854 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1855
1856 fnhe = find_exception(nhc, daddr);
1857 if (do_cache) {
1858 if (fnhe)
1859 rth = rcu_dereference(fnhe->fnhe_rth_input);
1860 else
1861 rth = rcu_dereference(nhc->nhc_rth_input);
1862 if (rt_cache_valid(rth)) {
1863 skb_dst_set_noref(skb, &rth->dst);
1864 goto out;
1865 }
1866 }
1867
1868 rth = rt_dst_alloc(out_dev->dev, 0, res->type, no_policy,
1869 IN_DEV_ORCONF(out_dev, NOXFRM));
1870 if (!rth) {
1871 err = -ENOBUFS;
1872 goto cleanup;
1873 }
1874
1875 rth->rt_is_input = 1;
1876 RT_CACHE_STAT_INC(in_slow_tot);
1877
1878 rth->dst.input = ip_forward;
1879
1880 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
1881 do_cache);
1882 lwtunnel_set_redirect(&rth->dst);
1883 skb_dst_set(skb, &rth->dst);
1884 out:
1885 err = 0;
1886 cleanup:
1887 return err;
1888 }
1889
1890 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1891 /* To make ICMP packets follow the right flow, the multipath hash is
1892 * calculated from the inner IP addresses.
1893 */
ip_multipath_l3_keys(const struct sk_buff * skb,struct flow_keys * hash_keys)1894 static void ip_multipath_l3_keys(const struct sk_buff *skb,
1895 struct flow_keys *hash_keys)
1896 {
1897 const struct iphdr *outer_iph = ip_hdr(skb);
1898 const struct iphdr *key_iph = outer_iph;
1899 const struct iphdr *inner_iph;
1900 const struct icmphdr *icmph;
1901 struct iphdr _inner_iph;
1902 struct icmphdr _icmph;
1903
1904 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1905 goto out;
1906
1907 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1908 goto out;
1909
1910 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph),
1911 &_icmph);
1912 if (!icmph)
1913 goto out;
1914
1915 if (!icmp_is_err(icmph->type))
1916 goto out;
1917
1918 inner_iph = skb_header_pointer(skb,
1919 outer_iph->ihl * 4 + sizeof(_icmph),
1920 sizeof(_inner_iph), &_inner_iph);
1921 if (!inner_iph)
1922 goto out;
1923
1924 key_iph = inner_iph;
1925 out:
1926 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1927 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1928 }
1929
fib_multipath_custom_hash_outer(const struct net * net,const struct sk_buff * skb,bool * p_has_inner)1930 static u32 fib_multipath_custom_hash_outer(const struct net *net,
1931 const struct sk_buff *skb,
1932 bool *p_has_inner)
1933 {
1934 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1935 struct flow_keys keys, hash_keys;
1936
1937 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1938 return 0;
1939
1940 memset(&hash_keys, 0, sizeof(hash_keys));
1941 skb_flow_dissect_flow_keys(skb, &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1942
1943 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1944 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1945 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1946 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1947 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1948 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1949 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1950 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1951 hash_keys.ports.src = keys.ports.src;
1952 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1953 hash_keys.ports.dst = keys.ports.dst;
1954
1955 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1956 return flow_hash_from_keys(&hash_keys);
1957 }
1958
fib_multipath_custom_hash_inner(const struct net * net,const struct sk_buff * skb,bool has_inner)1959 static u32 fib_multipath_custom_hash_inner(const struct net *net,
1960 const struct sk_buff *skb,
1961 bool has_inner)
1962 {
1963 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1964 struct flow_keys keys, hash_keys;
1965
1966 /* We assume the packet carries an encapsulation, but if none was
1967 * encountered during dissection of the outer flow, then there is no
1968 * point in calling the flow dissector again.
1969 */
1970 if (!has_inner)
1971 return 0;
1972
1973 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1974 return 0;
1975
1976 memset(&hash_keys, 0, sizeof(hash_keys));
1977 skb_flow_dissect_flow_keys(skb, &keys, 0);
1978
1979 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1980 return 0;
1981
1982 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1983 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1984 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1985 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1986 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1987 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1988 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1989 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1990 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1991 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1992 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1993 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1994 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1995 hash_keys.tags.flow_label = keys.tags.flow_label;
1996 }
1997
1998 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
1999 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2000 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
2001 hash_keys.ports.src = keys.ports.src;
2002 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
2003 hash_keys.ports.dst = keys.ports.dst;
2004
2005 return flow_hash_from_keys(&hash_keys);
2006 }
2007
fib_multipath_custom_hash_skb(const struct net * net,const struct sk_buff * skb)2008 static u32 fib_multipath_custom_hash_skb(const struct net *net,
2009 const struct sk_buff *skb)
2010 {
2011 u32 mhash, mhash_inner;
2012 bool has_inner = true;
2013
2014 mhash = fib_multipath_custom_hash_outer(net, skb, &has_inner);
2015 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
2016
2017 return jhash_2words(mhash, mhash_inner, 0);
2018 }
2019
fib_multipath_custom_hash_fl4(const struct net * net,const struct flowi4 * fl4)2020 static u32 fib_multipath_custom_hash_fl4(const struct net *net,
2021 const struct flowi4 *fl4)
2022 {
2023 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
2024 struct flow_keys hash_keys;
2025
2026 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
2027 return 0;
2028
2029 memset(&hash_keys, 0, sizeof(hash_keys));
2030 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2031 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2032 hash_keys.addrs.v4addrs.src = fl4->saddr;
2033 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2034 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2035 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2036 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2037 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2038 hash_keys.ports.src = fl4->fl4_sport;
2039 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2040 hash_keys.ports.dst = fl4->fl4_dport;
2041
2042 return flow_hash_from_keys(&hash_keys);
2043 }
2044
2045 /* if skb is set it will be used and fl4 can be NULL */
fib_multipath_hash(const struct net * net,const struct flowi4 * fl4,const struct sk_buff * skb,struct flow_keys * flkeys)2046 int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2047 const struct sk_buff *skb, struct flow_keys *flkeys)
2048 {
2049 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2050 struct flow_keys hash_keys;
2051 u32 mhash = 0;
2052
2053 switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
2054 case 0:
2055 memset(&hash_keys, 0, sizeof(hash_keys));
2056 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2057 if (skb) {
2058 ip_multipath_l3_keys(skb, &hash_keys);
2059 } else {
2060 hash_keys.addrs.v4addrs.src = fl4->saddr;
2061 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2062 }
2063 mhash = flow_hash_from_keys(&hash_keys);
2064 break;
2065 case 1:
2066 /* skb is currently provided only when forwarding */
2067 if (skb) {
2068 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2069 struct flow_keys keys;
2070
2071 /* short-circuit if we already have L4 hash present */
2072 if (skb->l4_hash)
2073 return skb_get_hash_raw(skb) >> 1;
2074
2075 memset(&hash_keys, 0, sizeof(hash_keys));
2076
2077 if (!flkeys) {
2078 skb_flow_dissect_flow_keys(skb, &keys, flag);
2079 flkeys = &keys;
2080 }
2081
2082 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2083 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2084 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2085 hash_keys.ports.src = flkeys->ports.src;
2086 hash_keys.ports.dst = flkeys->ports.dst;
2087 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2088 } else {
2089 memset(&hash_keys, 0, sizeof(hash_keys));
2090 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2091 hash_keys.addrs.v4addrs.src = fl4->saddr;
2092 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2093 hash_keys.ports.src = fl4->fl4_sport;
2094 hash_keys.ports.dst = fl4->fl4_dport;
2095 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2096 }
2097 mhash = flow_hash_from_keys(&hash_keys);
2098 break;
2099 case 2:
2100 memset(&hash_keys, 0, sizeof(hash_keys));
2101 /* skb is currently provided only when forwarding */
2102 if (skb) {
2103 struct flow_keys keys;
2104
2105 skb_flow_dissect_flow_keys(skb, &keys, 0);
2106 /* Inner can be v4 or v6 */
2107 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2108 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2109 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2110 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2111 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2112 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2113 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2114 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2115 hash_keys.tags.flow_label = keys.tags.flow_label;
2116 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2117 } else {
2118 /* Same as case 0 */
2119 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2120 ip_multipath_l3_keys(skb, &hash_keys);
2121 }
2122 } else {
2123 /* Same as case 0 */
2124 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2125 hash_keys.addrs.v4addrs.src = fl4->saddr;
2126 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2127 }
2128 mhash = flow_hash_from_keys(&hash_keys);
2129 break;
2130 case 3:
2131 if (skb)
2132 mhash = fib_multipath_custom_hash_skb(net, skb);
2133 else
2134 mhash = fib_multipath_custom_hash_fl4(net, fl4);
2135 break;
2136 }
2137
2138 if (multipath_hash)
2139 mhash = jhash_2words(mhash, multipath_hash, 0);
2140
2141 return mhash >> 1;
2142 }
2143 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
2144
ip_mkroute_input(struct sk_buff * skb,struct fib_result * res,struct in_device * in_dev,__be32 daddr,__be32 saddr,u32 tos,struct flow_keys * hkeys)2145 static int ip_mkroute_input(struct sk_buff *skb,
2146 struct fib_result *res,
2147 struct in_device *in_dev,
2148 __be32 daddr, __be32 saddr, u32 tos,
2149 struct flow_keys *hkeys)
2150 {
2151 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2152 if (res->fi && fib_info_num_path(res->fi) > 1) {
2153 int h = fib_multipath_hash(res->fi->fib_net, NULL, skb, hkeys);
2154
2155 fib_select_multipath(res, h);
2156 IPCB(skb)->flags |= IPSKB_MULTIPATH;
2157 }
2158 #endif
2159
2160 /* create a routing cache entry */
2161 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2162 }
2163
2164 /* Implements all the saddr-related checks as ip_route_input_slow(),
2165 * assuming daddr is valid and the destination is not a local broadcast one.
2166 * Uses the provided hint instead of performing a route lookup.
2167 */
ip_route_use_hint(struct sk_buff * skb,__be32 daddr,__be32 saddr,u8 tos,struct net_device * dev,const struct sk_buff * hint)2168 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2169 u8 tos, struct net_device *dev,
2170 const struct sk_buff *hint)
2171 {
2172 struct in_device *in_dev = __in_dev_get_rcu(dev);
2173 struct rtable *rt = skb_rtable(hint);
2174 struct net *net = dev_net(dev);
2175 int err = -EINVAL;
2176 u32 tag = 0;
2177
2178 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2179 goto martian_source;
2180
2181 if (ipv4_is_zeronet(saddr))
2182 goto martian_source;
2183
2184 if (ipv4_is_loopback(saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2185 goto martian_source;
2186
2187 if (rt->rt_type != RTN_LOCAL)
2188 goto skip_validate_source;
2189
2190 tos &= IPTOS_RT_MASK;
2191 err = fib_validate_source(skb, saddr, daddr, tos, 0, dev, in_dev, &tag);
2192 if (err < 0)
2193 goto martian_source;
2194
2195 skip_validate_source:
2196 skb_dst_copy(skb, hint);
2197 return 0;
2198
2199 martian_source:
2200 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2201 return err;
2202 }
2203
2204 /* get device for dst_alloc with local routes */
ip_rt_get_dev(struct net * net,const struct fib_result * res)2205 static struct net_device *ip_rt_get_dev(struct net *net,
2206 const struct fib_result *res)
2207 {
2208 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2209 struct net_device *dev = NULL;
2210
2211 if (nhc)
2212 dev = l3mdev_master_dev_rcu(nhc->nhc_dev);
2213
2214 return dev ? : net->loopback_dev;
2215 }
2216
2217 /*
2218 * NOTE. We drop all the packets that has local source
2219 * addresses, because every properly looped back packet
2220 * must have correct destination already attached by output routine.
2221 * Changes in the enforced policies must be applied also to
2222 * ip_route_use_hint().
2223 *
2224 * Such approach solves two big problems:
2225 * 1. Not simplex devices are handled properly.
2226 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2227 * called with rcu_read_lock()
2228 */
2229
ip_route_input_slow(struct sk_buff * skb,__be32 daddr,__be32 saddr,u8 tos,struct net_device * dev,struct fib_result * res)2230 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2231 u8 tos, struct net_device *dev,
2232 struct fib_result *res)
2233 {
2234 struct in_device *in_dev = __in_dev_get_rcu(dev);
2235 struct flow_keys *flkeys = NULL, _flkeys;
2236 struct net *net = dev_net(dev);
2237 struct ip_tunnel_info *tun_info;
2238 int err = -EINVAL;
2239 unsigned int flags = 0;
2240 u32 itag = 0;
2241 struct rtable *rth;
2242 struct flowi4 fl4;
2243 bool do_cache = true;
2244 bool no_policy;
2245
2246 /* IP on this device is disabled. */
2247
2248 if (!in_dev)
2249 goto out;
2250
2251 /* Check for the most weird martians, which can be not detected
2252 * by fib_lookup.
2253 */
2254
2255 tun_info = skb_tunnel_info(skb);
2256 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2257 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2258 else
2259 fl4.flowi4_tun_key.tun_id = 0;
2260 skb_dst_drop(skb);
2261
2262 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
2263 goto martian_source;
2264
2265 res->fi = NULL;
2266 res->table = NULL;
2267 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
2268 goto brd_input;
2269
2270 /* Accept zero addresses only to limited broadcast;
2271 * I even do not know to fix it or not. Waiting for complains :-)
2272 */
2273 if (ipv4_is_zeronet(saddr))
2274 goto martian_source;
2275
2276 if (ipv4_is_zeronet(daddr))
2277 goto martian_destination;
2278
2279 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2280 * and call it once if daddr or/and saddr are loopback addresses
2281 */
2282 if (ipv4_is_loopback(daddr)) {
2283 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2284 goto martian_destination;
2285 } else if (ipv4_is_loopback(saddr)) {
2286 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2287 goto martian_source;
2288 }
2289
2290 /*
2291 * Now we are ready to route packet.
2292 */
2293 fl4.flowi4_oif = 0;
2294 fl4.flowi4_iif = dev->ifindex;
2295 fl4.flowi4_mark = skb->mark;
2296 fl4.flowi4_tos = tos;
2297 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2298 fl4.flowi4_flags = 0;
2299 fl4.daddr = daddr;
2300 fl4.saddr = saddr;
2301 fl4.flowi4_uid = sock_net_uid(net, NULL);
2302 fl4.flowi4_multipath_hash = 0;
2303
2304 if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
2305 flkeys = &_flkeys;
2306 } else {
2307 fl4.flowi4_proto = 0;
2308 fl4.fl4_sport = 0;
2309 fl4.fl4_dport = 0;
2310 }
2311
2312 err = fib_lookup(net, &fl4, res, 0);
2313 if (err != 0) {
2314 if (!IN_DEV_FORWARD(in_dev))
2315 err = -EHOSTUNREACH;
2316 goto no_route;
2317 }
2318
2319 if (res->type == RTN_BROADCAST) {
2320 if (IN_DEV_BFORWARD(in_dev))
2321 goto make_route;
2322 /* not do cache if bc_forwarding is enabled */
2323 if (IPV4_DEVCONF_ALL(net, BC_FORWARDING))
2324 do_cache = false;
2325 goto brd_input;
2326 }
2327
2328 if (res->type == RTN_LOCAL) {
2329 err = fib_validate_source(skb, saddr, daddr, tos,
2330 0, dev, in_dev, &itag);
2331 if (err < 0)
2332 goto martian_source;
2333 goto local_input;
2334 }
2335
2336 if (!IN_DEV_FORWARD(in_dev)) {
2337 err = -EHOSTUNREACH;
2338 goto no_route;
2339 }
2340 if (res->type != RTN_UNICAST)
2341 goto martian_destination;
2342
2343 make_route:
2344 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
2345 out: return err;
2346
2347 brd_input:
2348 if (skb->protocol != htons(ETH_P_IP))
2349 goto e_inval;
2350
2351 if (!ipv4_is_zeronet(saddr)) {
2352 err = fib_validate_source(skb, saddr, 0, tos, 0, dev,
2353 in_dev, &itag);
2354 if (err < 0)
2355 goto martian_source;
2356 }
2357 flags |= RTCF_BROADCAST;
2358 res->type = RTN_BROADCAST;
2359 RT_CACHE_STAT_INC(in_brd);
2360
2361 local_input:
2362 no_policy = IN_DEV_ORCONF(in_dev, NOPOLICY);
2363 if (no_policy)
2364 IPCB(skb)->flags |= IPSKB_NOPOLICY;
2365
2366 do_cache &= res->fi && !itag;
2367 if (do_cache) {
2368 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2369
2370 rth = rcu_dereference(nhc->nhc_rth_input);
2371 if (rt_cache_valid(rth)) {
2372 skb_dst_set_noref(skb, &rth->dst);
2373 err = 0;
2374 goto out;
2375 }
2376 }
2377
2378 rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2379 flags | RTCF_LOCAL, res->type,
2380 no_policy, false);
2381 if (!rth)
2382 goto e_nobufs;
2383
2384 rth->dst.output= ip_rt_bug;
2385 #ifdef CONFIG_IP_ROUTE_CLASSID
2386 rth->dst.tclassid = itag;
2387 #endif
2388 rth->rt_is_input = 1;
2389
2390 RT_CACHE_STAT_INC(in_slow_tot);
2391 if (res->type == RTN_UNREACHABLE) {
2392 rth->dst.input= ip_error;
2393 rth->dst.error= -err;
2394 rth->rt_flags &= ~RTCF_LOCAL;
2395 }
2396
2397 if (do_cache) {
2398 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2399
2400 rth->dst.lwtstate = lwtstate_get(nhc->nhc_lwtstate);
2401 if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
2402 WARN_ON(rth->dst.input == lwtunnel_input);
2403 rth->dst.lwtstate->orig_input = rth->dst.input;
2404 rth->dst.input = lwtunnel_input;
2405 }
2406
2407 if (unlikely(!rt_cache_route(nhc, rth)))
2408 rt_add_uncached_list(rth);
2409 }
2410 skb_dst_set(skb, &rth->dst);
2411 err = 0;
2412 goto out;
2413
2414 no_route:
2415 RT_CACHE_STAT_INC(in_no_route);
2416 res->type = RTN_UNREACHABLE;
2417 res->fi = NULL;
2418 res->table = NULL;
2419 goto local_input;
2420
2421 /*
2422 * Do not cache martian addresses: they should be logged (RFC1812)
2423 */
2424 martian_destination:
2425 RT_CACHE_STAT_INC(in_martian_dst);
2426 #ifdef CONFIG_IP_ROUTE_VERBOSE
2427 if (IN_DEV_LOG_MARTIANS(in_dev))
2428 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2429 &daddr, &saddr, dev->name);
2430 #endif
2431
2432 e_inval:
2433 err = -EINVAL;
2434 goto out;
2435
2436 e_nobufs:
2437 err = -ENOBUFS;
2438 goto out;
2439
2440 martian_source:
2441 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2442 goto out;
2443 }
2444
ip_route_input_noref(struct sk_buff * skb,__be32 daddr,__be32 saddr,u8 tos,struct net_device * dev)2445 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2446 u8 tos, struct net_device *dev)
2447 {
2448 struct fib_result res;
2449 int err;
2450
2451 tos &= IPTOS_RT_MASK;
2452 rcu_read_lock();
2453 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
2454 rcu_read_unlock();
2455
2456 return err;
2457 }
2458 EXPORT_SYMBOL(ip_route_input_noref);
2459
2460 /* 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)2461 int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2462 u8 tos, struct net_device *dev, struct fib_result *res)
2463 {
2464 /* Multicast recognition logic is moved from route cache to here.
2465 * The problem was that too many Ethernet cards have broken/missing
2466 * hardware multicast filters :-( As result the host on multicasting
2467 * network acquires a lot of useless route cache entries, sort of
2468 * SDR messages from all the world. Now we try to get rid of them.
2469 * Really, provided software IP multicast filter is organized
2470 * reasonably (at least, hashed), it does not result in a slowdown
2471 * comparing with route cache reject entries.
2472 * Note, that multicast routers are not affected, because
2473 * route cache entry is created eventually.
2474 */
2475 if (ipv4_is_multicast(daddr)) {
2476 struct in_device *in_dev = __in_dev_get_rcu(dev);
2477 int our = 0;
2478 int err = -EINVAL;
2479
2480 if (!in_dev)
2481 return err;
2482 our = ip_check_mc_rcu(in_dev, daddr, saddr,
2483 ip_hdr(skb)->protocol);
2484
2485 /* check l3 master if no match yet */
2486 if (!our && netif_is_l3_slave(dev)) {
2487 struct in_device *l3_in_dev;
2488
2489 l3_in_dev = __in_dev_get_rcu(skb->dev);
2490 if (l3_in_dev)
2491 our = ip_check_mc_rcu(l3_in_dev, daddr, saddr,
2492 ip_hdr(skb)->protocol);
2493 }
2494
2495 if (our
2496 #ifdef CONFIG_IP_MROUTE
2497 ||
2498 (!ipv4_is_local_multicast(daddr) &&
2499 IN_DEV_MFORWARD(in_dev))
2500 #endif
2501 ) {
2502 err = ip_route_input_mc(skb, daddr, saddr,
2503 tos, dev, our);
2504 }
2505 return err;
2506 }
2507
2508 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2509 }
2510
2511 /* 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)2512 static struct rtable *__mkroute_output(const struct fib_result *res,
2513 const struct flowi4 *fl4, int orig_oif,
2514 struct net_device *dev_out,
2515 unsigned int flags)
2516 {
2517 struct fib_info *fi = res->fi;
2518 struct fib_nh_exception *fnhe;
2519 struct in_device *in_dev;
2520 u16 type = res->type;
2521 struct rtable *rth;
2522 bool do_cache;
2523
2524 in_dev = __in_dev_get_rcu(dev_out);
2525 if (!in_dev)
2526 return ERR_PTR(-EINVAL);
2527
2528 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2529 if (ipv4_is_loopback(fl4->saddr) &&
2530 !(dev_out->flags & IFF_LOOPBACK) &&
2531 !netif_is_l3_master(dev_out))
2532 return ERR_PTR(-EINVAL);
2533
2534 if (ipv4_is_lbcast(fl4->daddr))
2535 type = RTN_BROADCAST;
2536 else if (ipv4_is_multicast(fl4->daddr))
2537 type = RTN_MULTICAST;
2538 else if (ipv4_is_zeronet(fl4->daddr))
2539 return ERR_PTR(-EINVAL);
2540
2541 if (dev_out->flags & IFF_LOOPBACK)
2542 flags |= RTCF_LOCAL;
2543
2544 do_cache = true;
2545 if (type == RTN_BROADCAST) {
2546 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2547 fi = NULL;
2548 } else if (type == RTN_MULTICAST) {
2549 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2550 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr,
2551 fl4->flowi4_proto))
2552 flags &= ~RTCF_LOCAL;
2553 else
2554 do_cache = false;
2555 /* If multicast route do not exist use
2556 * default one, but do not gateway in this case.
2557 * Yes, it is hack.
2558 */
2559 if (fi && res->prefixlen < 4)
2560 fi = NULL;
2561 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2562 (orig_oif != dev_out->ifindex)) {
2563 /* For local routes that require a particular output interface
2564 * we do not want to cache the result. Caching the result
2565 * causes incorrect behaviour when there are multiple source
2566 * addresses on the interface, the end result being that if the
2567 * intended recipient is waiting on that interface for the
2568 * packet he won't receive it because it will be delivered on
2569 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2570 * be set to the loopback interface as well.
2571 */
2572 do_cache = false;
2573 }
2574
2575 fnhe = NULL;
2576 do_cache &= fi != NULL;
2577 if (fi) {
2578 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2579 struct rtable __rcu **prth;
2580
2581 fnhe = find_exception(nhc, fl4->daddr);
2582 if (!do_cache)
2583 goto add;
2584 if (fnhe) {
2585 prth = &fnhe->fnhe_rth_output;
2586 } else {
2587 if (unlikely(fl4->flowi4_flags &
2588 FLOWI_FLAG_KNOWN_NH &&
2589 !(nhc->nhc_gw_family &&
2590 nhc->nhc_scope == RT_SCOPE_LINK))) {
2591 do_cache = false;
2592 goto add;
2593 }
2594 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2595 }
2596 rth = rcu_dereference(*prth);
2597 if (rt_cache_valid(rth) && dst_hold_safe(&rth->dst))
2598 return rth;
2599 }
2600
2601 add:
2602 rth = rt_dst_alloc(dev_out, flags, type,
2603 IN_DEV_ORCONF(in_dev, NOPOLICY),
2604 IN_DEV_ORCONF(in_dev, NOXFRM));
2605 if (!rth)
2606 return ERR_PTR(-ENOBUFS);
2607
2608 rth->rt_iif = orig_oif;
2609
2610 RT_CACHE_STAT_INC(out_slow_tot);
2611
2612 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2613 if (flags & RTCF_LOCAL &&
2614 !(dev_out->flags & IFF_LOOPBACK)) {
2615 rth->dst.output = ip_mc_output;
2616 RT_CACHE_STAT_INC(out_slow_mc);
2617 }
2618 #ifdef CONFIG_IP_MROUTE
2619 if (type == RTN_MULTICAST) {
2620 if (IN_DEV_MFORWARD(in_dev) &&
2621 !ipv4_is_local_multicast(fl4->daddr)) {
2622 rth->dst.input = ip_mr_input;
2623 rth->dst.output = ip_mc_output;
2624 }
2625 }
2626 #endif
2627 }
2628
2629 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
2630 lwtunnel_set_redirect(&rth->dst);
2631
2632 return rth;
2633 }
2634
2635 /*
2636 * Major route resolver routine.
2637 */
2638
ip_route_output_key_hash(struct net * net,struct flowi4 * fl4,const struct sk_buff * skb)2639 struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2640 const struct sk_buff *skb)
2641 {
2642 struct fib_result res = {
2643 .type = RTN_UNSPEC,
2644 .fi = NULL,
2645 .table = NULL,
2646 .tclassid = 0,
2647 };
2648 struct rtable *rth;
2649
2650 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2651 ip_rt_fix_tos(fl4);
2652
2653 rcu_read_lock();
2654 rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);
2655 rcu_read_unlock();
2656
2657 return rth;
2658 }
2659 EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2660
ip_route_output_key_hash_rcu(struct net * net,struct flowi4 * fl4,struct fib_result * res,const struct sk_buff * skb)2661 struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2662 struct fib_result *res,
2663 const struct sk_buff *skb)
2664 {
2665 struct net_device *dev_out = NULL;
2666 int orig_oif = fl4->flowi4_oif;
2667 unsigned int flags = 0;
2668 struct rtable *rth;
2669 int err;
2670
2671 if (fl4->saddr) {
2672 if (ipv4_is_multicast(fl4->saddr) ||
2673 ipv4_is_lbcast(fl4->saddr) ||
2674 ipv4_is_zeronet(fl4->saddr)) {
2675 rth = ERR_PTR(-EINVAL);
2676 goto out;
2677 }
2678
2679 rth = ERR_PTR(-ENETUNREACH);
2680
2681 /* I removed check for oif == dev_out->oif here.
2682 * It was wrong for two reasons:
2683 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2684 * is assigned to multiple interfaces.
2685 * 2. Moreover, we are allowed to send packets with saddr
2686 * of another iface. --ANK
2687 */
2688
2689 if (fl4->flowi4_oif == 0 &&
2690 (ipv4_is_multicast(fl4->daddr) ||
2691 ipv4_is_lbcast(fl4->daddr))) {
2692 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2693 dev_out = __ip_dev_find(net, fl4->saddr, false);
2694 if (!dev_out)
2695 goto out;
2696
2697 /* Special hack: user can direct multicasts
2698 * and limited broadcast via necessary interface
2699 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2700 * This hack is not just for fun, it allows
2701 * vic,vat and friends to work.
2702 * They bind socket to loopback, set ttl to zero
2703 * and expect that it will work.
2704 * From the viewpoint of routing cache they are broken,
2705 * because we are not allowed to build multicast path
2706 * with loopback source addr (look, routing cache
2707 * cannot know, that ttl is zero, so that packet
2708 * will not leave this host and route is valid).
2709 * Luckily, this hack is good workaround.
2710 */
2711
2712 fl4->flowi4_oif = dev_out->ifindex;
2713 goto make_route;
2714 }
2715
2716 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2717 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2718 if (!__ip_dev_find(net, fl4->saddr, false))
2719 goto out;
2720 }
2721 }
2722
2723
2724 if (fl4->flowi4_oif) {
2725 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif);
2726 rth = ERR_PTR(-ENODEV);
2727 if (!dev_out)
2728 goto out;
2729
2730 /* RACE: Check return value of inet_select_addr instead. */
2731 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) {
2732 rth = ERR_PTR(-ENETUNREACH);
2733 goto out;
2734 }
2735 if (ipv4_is_local_multicast(fl4->daddr) ||
2736 ipv4_is_lbcast(fl4->daddr) ||
2737 fl4->flowi4_proto == IPPROTO_IGMP) {
2738 if (!fl4->saddr)
2739 fl4->saddr = inet_select_addr(dev_out, 0,
2740 RT_SCOPE_LINK);
2741 goto make_route;
2742 }
2743 if (!fl4->saddr) {
2744 if (ipv4_is_multicast(fl4->daddr))
2745 fl4->saddr = inet_select_addr(dev_out, 0,
2746 fl4->flowi4_scope);
2747 else if (!fl4->daddr)
2748 fl4->saddr = inet_select_addr(dev_out, 0,
2749 RT_SCOPE_HOST);
2750 }
2751 }
2752
2753 if (!fl4->daddr) {
2754 fl4->daddr = fl4->saddr;
2755 if (!fl4->daddr)
2756 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2757 dev_out = net->loopback_dev;
2758 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2759 res->type = RTN_LOCAL;
2760 flags |= RTCF_LOCAL;
2761 goto make_route;
2762 }
2763
2764 err = fib_lookup(net, fl4, res, 0);
2765 if (err) {
2766 res->fi = NULL;
2767 res->table = NULL;
2768 if (fl4->flowi4_oif &&
2769 (ipv4_is_multicast(fl4->daddr) ||
2770 !netif_index_is_l3_master(net, fl4->flowi4_oif))) {
2771 /* Apparently, routing tables are wrong. Assume,
2772 * that the destination is on link.
2773 *
2774 * WHY? DW.
2775 * Because we are allowed to send to iface
2776 * even if it has NO routes and NO assigned
2777 * addresses. When oif is specified, routing
2778 * tables are looked up with only one purpose:
2779 * to catch if destination is gatewayed, rather than
2780 * direct. Moreover, if MSG_DONTROUTE is set,
2781 * we send packet, ignoring both routing tables
2782 * and ifaddr state. --ANK
2783 *
2784 *
2785 * We could make it even if oif is unknown,
2786 * likely IPv6, but we do not.
2787 */
2788
2789 if (fl4->saddr == 0)
2790 fl4->saddr = inet_select_addr(dev_out, 0,
2791 RT_SCOPE_LINK);
2792 res->type = RTN_UNICAST;
2793 goto make_route;
2794 }
2795 rth = ERR_PTR(err);
2796 goto out;
2797 }
2798
2799 if (res->type == RTN_LOCAL) {
2800 if (!fl4->saddr) {
2801 if (res->fi->fib_prefsrc)
2802 fl4->saddr = res->fi->fib_prefsrc;
2803 else
2804 fl4->saddr = fl4->daddr;
2805 }
2806
2807 /* L3 master device is the loopback for that domain */
2808 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2809 net->loopback_dev;
2810
2811 /* make sure orig_oif points to fib result device even
2812 * though packet rx/tx happens over loopback or l3mdev
2813 */
2814 orig_oif = FIB_RES_OIF(*res);
2815
2816 fl4->flowi4_oif = dev_out->ifindex;
2817 flags |= RTCF_LOCAL;
2818 goto make_route;
2819 }
2820
2821 fib_select_path(net, res, fl4, skb);
2822
2823 dev_out = FIB_RES_DEV(*res);
2824
2825 make_route:
2826 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2827
2828 out:
2829 return rth;
2830 }
2831
2832 static struct dst_ops ipv4_dst_blackhole_ops = {
2833 .family = AF_INET,
2834 .default_advmss = ipv4_default_advmss,
2835 .neigh_lookup = ipv4_neigh_lookup,
2836 .check = dst_blackhole_check,
2837 .cow_metrics = dst_blackhole_cow_metrics,
2838 .update_pmtu = dst_blackhole_update_pmtu,
2839 .redirect = dst_blackhole_redirect,
2840 .mtu = dst_blackhole_mtu,
2841 };
2842
ipv4_blackhole_route(struct net * net,struct dst_entry * dst_orig)2843 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2844 {
2845 struct rtable *ort = (struct rtable *) dst_orig;
2846 struct rtable *rt;
2847
2848 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_DEAD, 0);
2849 if (rt) {
2850 struct dst_entry *new = &rt->dst;
2851
2852 new->__use = 1;
2853 new->input = dst_discard;
2854 new->output = dst_discard_out;
2855
2856 new->dev = net->loopback_dev;
2857 dev_hold(new->dev);
2858
2859 rt->rt_is_input = ort->rt_is_input;
2860 rt->rt_iif = ort->rt_iif;
2861 rt->rt_pmtu = ort->rt_pmtu;
2862 rt->rt_mtu_locked = ort->rt_mtu_locked;
2863
2864 rt->rt_genid = rt_genid_ipv4(net);
2865 rt->rt_flags = ort->rt_flags;
2866 rt->rt_type = ort->rt_type;
2867 rt->rt_uses_gateway = ort->rt_uses_gateway;
2868 rt->rt_gw_family = ort->rt_gw_family;
2869 if (rt->rt_gw_family == AF_INET)
2870 rt->rt_gw4 = ort->rt_gw4;
2871 else if (rt->rt_gw_family == AF_INET6)
2872 rt->rt_gw6 = ort->rt_gw6;
2873
2874 INIT_LIST_HEAD(&rt->rt_uncached);
2875 }
2876
2877 dst_release(dst_orig);
2878
2879 return rt ? &rt->dst : ERR_PTR(-ENOMEM);
2880 }
2881
ip_route_output_flow(struct net * net,struct flowi4 * flp4,const struct sock * sk)2882 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2883 const struct sock *sk)
2884 {
2885 struct rtable *rt = __ip_route_output_key(net, flp4);
2886
2887 if (IS_ERR(rt))
2888 return rt;
2889
2890 if (flp4->flowi4_proto) {
2891 flp4->flowi4_oif = rt->dst.dev->ifindex;
2892 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst,
2893 flowi4_to_flowi(flp4),
2894 sk, 0);
2895 }
2896
2897 return rt;
2898 }
2899 EXPORT_SYMBOL_GPL(ip_route_output_flow);
2900
ip_route_output_tunnel(struct sk_buff * skb,struct net_device * dev,struct net * net,__be32 * saddr,const struct ip_tunnel_info * info,u8 protocol,bool use_cache)2901 struct rtable *ip_route_output_tunnel(struct sk_buff *skb,
2902 struct net_device *dev,
2903 struct net *net, __be32 *saddr,
2904 const struct ip_tunnel_info *info,
2905 u8 protocol, bool use_cache)
2906 {
2907 #ifdef CONFIG_DST_CACHE
2908 struct dst_cache *dst_cache;
2909 #endif
2910 struct rtable *rt = NULL;
2911 struct flowi4 fl4;
2912 __u8 tos;
2913
2914 #ifdef CONFIG_DST_CACHE
2915 dst_cache = (struct dst_cache *)&info->dst_cache;
2916 if (use_cache) {
2917 rt = dst_cache_get_ip4(dst_cache, saddr);
2918 if (rt)
2919 return rt;
2920 }
2921 #endif
2922 memset(&fl4, 0, sizeof(fl4));
2923 fl4.flowi4_mark = skb->mark;
2924 fl4.flowi4_proto = protocol;
2925 fl4.daddr = info->key.u.ipv4.dst;
2926 fl4.saddr = info->key.u.ipv4.src;
2927 tos = info->key.tos;
2928 fl4.flowi4_tos = RT_TOS(tos);
2929
2930 rt = ip_route_output_key(net, &fl4);
2931 if (IS_ERR(rt)) {
2932 netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr);
2933 return ERR_PTR(-ENETUNREACH);
2934 }
2935 if (rt->dst.dev == dev) { /* is this necessary? */
2936 netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr);
2937 ip_rt_put(rt);
2938 return ERR_PTR(-ELOOP);
2939 }
2940 #ifdef CONFIG_DST_CACHE
2941 if (use_cache)
2942 dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
2943 #endif
2944 *saddr = fl4.saddr;
2945 return rt;
2946 }
2947 EXPORT_SYMBOL_GPL(ip_route_output_tunnel);
2948
2949 /* called with rcu_read_lock held */
rt_fill_info(struct net * net,__be32 dst,__be32 src,struct rtable * rt,u32 table_id,struct flowi4 * fl4,struct sk_buff * skb,u32 portid,u32 seq,unsigned int flags)2950 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2951 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2952 struct sk_buff *skb, u32 portid, u32 seq,
2953 unsigned int flags)
2954 {
2955 struct rtmsg *r;
2956 struct nlmsghdr *nlh;
2957 unsigned long expires = 0;
2958 u32 error;
2959 u32 metrics[RTAX_MAX];
2960
2961 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
2962 if (!nlh)
2963 return -EMSGSIZE;
2964
2965 r = nlmsg_data(nlh);
2966 r->rtm_family = AF_INET;
2967 r->rtm_dst_len = 32;
2968 r->rtm_src_len = 0;
2969 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2970 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2971 if (nla_put_u32(skb, RTA_TABLE, table_id))
2972 goto nla_put_failure;
2973 r->rtm_type = rt->rt_type;
2974 r->rtm_scope = RT_SCOPE_UNIVERSE;
2975 r->rtm_protocol = RTPROT_UNSPEC;
2976 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2977 if (rt->rt_flags & RTCF_NOTIFY)
2978 r->rtm_flags |= RTM_F_NOTIFY;
2979 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2980 r->rtm_flags |= RTCF_DOREDIRECT;
2981
2982 if (nla_put_in_addr(skb, RTA_DST, dst))
2983 goto nla_put_failure;
2984 if (src) {
2985 r->rtm_src_len = 32;
2986 if (nla_put_in_addr(skb, RTA_SRC, src))
2987 goto nla_put_failure;
2988 }
2989 if (rt->dst.dev &&
2990 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
2991 goto nla_put_failure;
2992 if (rt->dst.lwtstate &&
2993 lwtunnel_fill_encap(skb, rt->dst.lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
2994 goto nla_put_failure;
2995 #ifdef CONFIG_IP_ROUTE_CLASSID
2996 if (rt->dst.tclassid &&
2997 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid))
2998 goto nla_put_failure;
2999 #endif
3000 if (fl4 && !rt_is_input_route(rt) &&
3001 fl4->saddr != src) {
3002 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
3003 goto nla_put_failure;
3004 }
3005 if (rt->rt_uses_gateway) {
3006 if (rt->rt_gw_family == AF_INET &&
3007 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
3008 goto nla_put_failure;
3009 } else if (rt->rt_gw_family == AF_INET6) {
3010 int alen = sizeof(struct in6_addr);
3011 struct nlattr *nla;
3012 struct rtvia *via;
3013
3014 nla = nla_reserve(skb, RTA_VIA, alen + 2);
3015 if (!nla)
3016 goto nla_put_failure;
3017
3018 via = nla_data(nla);
3019 via->rtvia_family = AF_INET6;
3020 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
3021 }
3022 }
3023
3024 expires = rt->dst.expires;
3025 if (expires) {
3026 unsigned long now = jiffies;
3027
3028 if (time_before(now, expires))
3029 expires -= now;
3030 else
3031 expires = 0;
3032 }
3033
3034 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
3035 if (rt->rt_pmtu && expires)
3036 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
3037 if (rt->rt_mtu_locked && expires)
3038 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
3039 if (rtnetlink_put_metrics(skb, metrics) < 0)
3040 goto nla_put_failure;
3041
3042 if (fl4) {
3043 if (fl4->flowi4_mark &&
3044 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark))
3045 goto nla_put_failure;
3046
3047 if (!uid_eq(fl4->flowi4_uid, INVALID_UID) &&
3048 nla_put_u32(skb, RTA_UID,
3049 from_kuid_munged(current_user_ns(),
3050 fl4->flowi4_uid)))
3051 goto nla_put_failure;
3052
3053 if (rt_is_input_route(rt)) {
3054 #ifdef CONFIG_IP_MROUTE
3055 if (ipv4_is_multicast(dst) &&
3056 !ipv4_is_local_multicast(dst) &&
3057 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) {
3058 int err = ipmr_get_route(net, skb,
3059 fl4->saddr, fl4->daddr,
3060 r, portid);
3061
3062 if (err <= 0) {
3063 if (err == 0)
3064 return 0;
3065 goto nla_put_failure;
3066 }
3067 } else
3068 #endif
3069 if (nla_put_u32(skb, RTA_IIF, fl4->flowi4_iif))
3070 goto nla_put_failure;
3071 }
3072 }
3073
3074 error = rt->dst.error;
3075
3076 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0)
3077 goto nla_put_failure;
3078
3079 nlmsg_end(skb, nlh);
3080 return 0;
3081
3082 nla_put_failure:
3083 nlmsg_cancel(skb, nlh);
3084 return -EMSGSIZE;
3085 }
3086
fnhe_dump_bucket(struct net * net,struct sk_buff * skb,struct netlink_callback * cb,u32 table_id,struct fnhe_hash_bucket * bucket,int genid,int * fa_index,int fa_start,unsigned int flags)3087 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3088 struct netlink_callback *cb, u32 table_id,
3089 struct fnhe_hash_bucket *bucket, int genid,
3090 int *fa_index, int fa_start, unsigned int flags)
3091 {
3092 int i;
3093
3094 for (i = 0; i < FNHE_HASH_SIZE; i++) {
3095 struct fib_nh_exception *fnhe;
3096
3097 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3098 fnhe = rcu_dereference(fnhe->fnhe_next)) {
3099 struct rtable *rt;
3100 int err;
3101
3102 if (*fa_index < fa_start)
3103 goto next;
3104
3105 if (fnhe->fnhe_genid != genid)
3106 goto next;
3107
3108 if (fnhe->fnhe_expires &&
3109 time_after(jiffies, fnhe->fnhe_expires))
3110 goto next;
3111
3112 rt = rcu_dereference(fnhe->fnhe_rth_input);
3113 if (!rt)
3114 rt = rcu_dereference(fnhe->fnhe_rth_output);
3115 if (!rt)
3116 goto next;
3117
3118 err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
3119 table_id, NULL, skb,
3120 NETLINK_CB(cb->skb).portid,
3121 cb->nlh->nlmsg_seq, flags);
3122 if (err)
3123 return err;
3124 next:
3125 (*fa_index)++;
3126 }
3127 }
3128
3129 return 0;
3130 }
3131
fib_dump_info_fnhe(struct sk_buff * skb,struct netlink_callback * cb,u32 table_id,struct fib_info * fi,int * fa_index,int fa_start,unsigned int flags)3132 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3133 u32 table_id, struct fib_info *fi,
3134 int *fa_index, int fa_start, unsigned int flags)
3135 {
3136 struct net *net = sock_net(cb->skb->sk);
3137 int nhsel, genid = fnhe_genid(net);
3138
3139 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3140 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3141 struct fnhe_hash_bucket *bucket;
3142 int err;
3143
3144 if (nhc->nhc_flags & RTNH_F_DEAD)
3145 continue;
3146
3147 rcu_read_lock();
3148 bucket = rcu_dereference(nhc->nhc_exceptions);
3149 err = 0;
3150 if (bucket)
3151 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3152 genid, fa_index, fa_start,
3153 flags);
3154 rcu_read_unlock();
3155 if (err)
3156 return err;
3157 }
3158
3159 return 0;
3160 }
3161
inet_rtm_getroute_build_skb(__be32 src,__be32 dst,u8 ip_proto,__be16 sport,__be16 dport)3162 static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3163 u8 ip_proto, __be16 sport,
3164 __be16 dport)
3165 {
3166 struct sk_buff *skb;
3167 struct iphdr *iph;
3168
3169 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3170 if (!skb)
3171 return NULL;
3172
3173 /* Reserve room for dummy headers, this skb can pass
3174 * through good chunk of routing engine.
3175 */
3176 skb_reset_mac_header(skb);
3177 skb_reset_network_header(skb);
3178 skb->protocol = htons(ETH_P_IP);
3179 iph = skb_put(skb, sizeof(struct iphdr));
3180 iph->protocol = ip_proto;
3181 iph->saddr = src;
3182 iph->daddr = dst;
3183 iph->version = 0x4;
3184 iph->frag_off = 0;
3185 iph->ihl = 0x5;
3186 skb_set_transport_header(skb, skb->len);
3187
3188 switch (iph->protocol) {
3189 case IPPROTO_UDP: {
3190 struct udphdr *udph;
3191
3192 udph = skb_put_zero(skb, sizeof(struct udphdr));
3193 udph->source = sport;
3194 udph->dest = dport;
3195 udph->len = htons(sizeof(struct udphdr));
3196 udph->check = 0;
3197 break;
3198 }
3199 case IPPROTO_TCP: {
3200 struct tcphdr *tcph;
3201
3202 tcph = skb_put_zero(skb, sizeof(struct tcphdr));
3203 tcph->source = sport;
3204 tcph->dest = dport;
3205 tcph->doff = sizeof(struct tcphdr) / 4;
3206 tcph->rst = 1;
3207 tcph->check = ~tcp_v4_check(sizeof(struct tcphdr),
3208 src, dst, 0);
3209 break;
3210 }
3211 case IPPROTO_ICMP: {
3212 struct icmphdr *icmph;
3213
3214 icmph = skb_put_zero(skb, sizeof(struct icmphdr));
3215 icmph->type = ICMP_ECHO;
3216 icmph->code = 0;
3217 }
3218 }
3219
3220 return skb;
3221 }
3222
inet_rtm_valid_getroute_req(struct sk_buff * skb,const struct nlmsghdr * nlh,struct nlattr ** tb,struct netlink_ext_ack * extack)3223 static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3224 const struct nlmsghdr *nlh,
3225 struct nlattr **tb,
3226 struct netlink_ext_ack *extack)
3227 {
3228 struct rtmsg *rtm;
3229 int i, err;
3230
3231 if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
3232 NL_SET_ERR_MSG(extack,
3233 "ipv4: Invalid header for route get request");
3234 return -EINVAL;
3235 }
3236
3237 if (!netlink_strict_get_check(skb))
3238 return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
3239 rtm_ipv4_policy, extack);
3240
3241 rtm = nlmsg_data(nlh);
3242 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3243 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3244 rtm->rtm_table || rtm->rtm_protocol ||
3245 rtm->rtm_scope || rtm->rtm_type) {
3246 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3247 return -EINVAL;
3248 }
3249
3250 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3251 RTM_F_LOOKUP_TABLE |
3252 RTM_F_FIB_MATCH)) {
3253 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3254 return -EINVAL;
3255 }
3256
3257 err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
3258 rtm_ipv4_policy, extack);
3259 if (err)
3260 return err;
3261
3262 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3263 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3264 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3265 return -EINVAL;
3266 }
3267
3268 for (i = 0; i <= RTA_MAX; i++) {
3269 if (!tb[i])
3270 continue;
3271
3272 switch (i) {
3273 case RTA_IIF:
3274 case RTA_OIF:
3275 case RTA_SRC:
3276 case RTA_DST:
3277 case RTA_IP_PROTO:
3278 case RTA_SPORT:
3279 case RTA_DPORT:
3280 case RTA_MARK:
3281 case RTA_UID:
3282 break;
3283 default:
3284 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3285 return -EINVAL;
3286 }
3287 }
3288
3289 return 0;
3290 }
3291
inet_rtm_getroute(struct sk_buff * in_skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)3292 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3293 struct netlink_ext_ack *extack)
3294 {
3295 struct net *net = sock_net(in_skb->sk);
3296 struct nlattr *tb[RTA_MAX+1];
3297 u32 table_id = RT_TABLE_MAIN;
3298 __be16 sport = 0, dport = 0;
3299 struct fib_result res = {};
3300 u8 ip_proto = IPPROTO_UDP;
3301 struct rtable *rt = NULL;
3302 struct sk_buff *skb;
3303 struct rtmsg *rtm;
3304 struct flowi4 fl4 = {};
3305 __be32 dst = 0;
3306 __be32 src = 0;
3307 kuid_t uid;
3308 u32 iif;
3309 int err;
3310 int mark;
3311
3312 err = inet_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
3313 if (err < 0)
3314 return err;
3315
3316 rtm = nlmsg_data(nlh);
3317 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
3318 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
3319 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0;
3320 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0;
3321 if (tb[RTA_UID])
3322 uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));
3323 else
3324 uid = (iif ? INVALID_UID : current_uid());
3325
3326 if (tb[RTA_IP_PROTO]) {
3327 err = rtm_getroute_parse_ip_proto(tb[RTA_IP_PROTO],
3328 &ip_proto, AF_INET, extack);
3329 if (err)
3330 return err;
3331 }
3332
3333 if (tb[RTA_SPORT])
3334 sport = nla_get_be16(tb[RTA_SPORT]);
3335
3336 if (tb[RTA_DPORT])
3337 dport = nla_get_be16(tb[RTA_DPORT]);
3338
3339 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3340 if (!skb)
3341 return -ENOBUFS;
3342
3343 fl4.daddr = dst;
3344 fl4.saddr = src;
3345 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK;
3346 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0;
3347 fl4.flowi4_mark = mark;
3348 fl4.flowi4_uid = uid;
3349 if (sport)
3350 fl4.fl4_sport = sport;
3351 if (dport)
3352 fl4.fl4_dport = dport;
3353 fl4.flowi4_proto = ip_proto;
3354
3355 rcu_read_lock();
3356
3357 if (iif) {
3358 struct net_device *dev;
3359
3360 dev = dev_get_by_index_rcu(net, iif);
3361 if (!dev) {
3362 err = -ENODEV;
3363 goto errout_rcu;
3364 }
3365
3366 fl4.flowi4_iif = iif; /* for rt_fill_info */
3367 skb->dev = dev;
3368 skb->mark = mark;
3369 err = ip_route_input_rcu(skb, dst, src,
3370 rtm->rtm_tos & IPTOS_RT_MASK, dev,
3371 &res);
3372
3373 rt = skb_rtable(skb);
3374 if (err == 0 && rt->dst.error)
3375 err = -rt->dst.error;
3376 } else {
3377 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3378 skb->dev = net->loopback_dev;
3379 rt = ip_route_output_key_hash_rcu(net, &fl4, &res, skb);
3380 err = 0;
3381 if (IS_ERR(rt))
3382 err = PTR_ERR(rt);
3383 else
3384 skb_dst_set(skb, &rt->dst);
3385 }
3386
3387 if (err)
3388 goto errout_rcu;
3389
3390 if (rtm->rtm_flags & RTM_F_NOTIFY)
3391 rt->rt_flags |= RTCF_NOTIFY;
3392
3393 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3394 table_id = res.table ? res.table->tb_id : 0;
3395
3396 /* reset skb for netlink reply msg */
3397 skb_trim(skb, 0);
3398 skb_reset_network_header(skb);
3399 skb_reset_transport_header(skb);
3400 skb_reset_mac_header(skb);
3401
3402 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3403 struct fib_rt_info fri;
3404
3405 if (!res.fi) {
3406 err = fib_props[res.type].error;
3407 if (!err)
3408 err = -EHOSTUNREACH;
3409 goto errout_rcu;
3410 }
3411 fri.fi = res.fi;
3412 fri.tb_id = table_id;
3413 fri.dst = res.prefix;
3414 fri.dst_len = res.prefixlen;
3415 fri.tos = fl4.flowi4_tos;
3416 fri.type = rt->rt_type;
3417 fri.offload = 0;
3418 fri.trap = 0;
3419 fri.offload_failed = 0;
3420 if (res.fa_head) {
3421 struct fib_alias *fa;
3422
3423 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3424 u8 slen = 32 - fri.dst_len;
3425
3426 if (fa->fa_slen == slen &&
3427 fa->tb_id == fri.tb_id &&
3428 fa->fa_tos == fri.tos &&
3429 fa->fa_info == res.fi &&
3430 fa->fa_type == fri.type) {
3431 fri.offload = READ_ONCE(fa->offload);
3432 fri.trap = READ_ONCE(fa->trap);
3433 fri.offload_failed =
3434 READ_ONCE(fa->offload_failed);
3435 break;
3436 }
3437 }
3438 }
3439 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3440 nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
3441 } else {
3442 err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
3443 NETLINK_CB(in_skb).portid,
3444 nlh->nlmsg_seq, 0);
3445 }
3446 if (err < 0)
3447 goto errout_rcu;
3448
3449 rcu_read_unlock();
3450
3451 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3452
3453 errout_free:
3454 return err;
3455 errout_rcu:
3456 rcu_read_unlock();
3457 kfree_skb(skb);
3458 goto errout_free;
3459 }
3460
ip_rt_multicast_event(struct in_device * in_dev)3461 void ip_rt_multicast_event(struct in_device *in_dev)
3462 {
3463 rt_cache_flush(dev_net(in_dev->dev));
3464 }
3465
3466 #ifdef CONFIG_SYSCTL
3467 static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3468 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3469 static int ip_rt_gc_elasticity __read_mostly = 8;
3470 static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3471
ipv4_sysctl_rtcache_flush(struct ctl_table * __ctl,int write,void * buffer,size_t * lenp,loff_t * ppos)3472 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3473 void *buffer, size_t *lenp, loff_t *ppos)
3474 {
3475 struct net *net = (struct net *)__ctl->extra1;
3476
3477 if (write) {
3478 rt_cache_flush(net);
3479 fnhe_genid_bump(net);
3480 return 0;
3481 }
3482
3483 return -EINVAL;
3484 }
3485
3486 static struct ctl_table ipv4_route_table[] = {
3487 {
3488 .procname = "gc_thresh",
3489 .data = &ipv4_dst_ops.gc_thresh,
3490 .maxlen = sizeof(int),
3491 .mode = 0644,
3492 .proc_handler = proc_dointvec,
3493 },
3494 {
3495 .procname = "max_size",
3496 .data = &ip_rt_max_size,
3497 .maxlen = sizeof(int),
3498 .mode = 0644,
3499 .proc_handler = proc_dointvec,
3500 },
3501 {
3502 /* Deprecated. Use gc_min_interval_ms */
3503
3504 .procname = "gc_min_interval",
3505 .data = &ip_rt_gc_min_interval,
3506 .maxlen = sizeof(int),
3507 .mode = 0644,
3508 .proc_handler = proc_dointvec_jiffies,
3509 },
3510 {
3511 .procname = "gc_min_interval_ms",
3512 .data = &ip_rt_gc_min_interval,
3513 .maxlen = sizeof(int),
3514 .mode = 0644,
3515 .proc_handler = proc_dointvec_ms_jiffies,
3516 },
3517 {
3518 .procname = "gc_timeout",
3519 .data = &ip_rt_gc_timeout,
3520 .maxlen = sizeof(int),
3521 .mode = 0644,
3522 .proc_handler = proc_dointvec_jiffies,
3523 },
3524 {
3525 .procname = "gc_interval",
3526 .data = &ip_rt_gc_interval,
3527 .maxlen = sizeof(int),
3528 .mode = 0644,
3529 .proc_handler = proc_dointvec_jiffies,
3530 },
3531 {
3532 .procname = "redirect_load",
3533 .data = &ip_rt_redirect_load,
3534 .maxlen = sizeof(int),
3535 .mode = 0644,
3536 .proc_handler = proc_dointvec,
3537 },
3538 {
3539 .procname = "redirect_number",
3540 .data = &ip_rt_redirect_number,
3541 .maxlen = sizeof(int),
3542 .mode = 0644,
3543 .proc_handler = proc_dointvec,
3544 },
3545 {
3546 .procname = "redirect_silence",
3547 .data = &ip_rt_redirect_silence,
3548 .maxlen = sizeof(int),
3549 .mode = 0644,
3550 .proc_handler = proc_dointvec,
3551 },
3552 {
3553 .procname = "error_cost",
3554 .data = &ip_rt_error_cost,
3555 .maxlen = sizeof(int),
3556 .mode = 0644,
3557 .proc_handler = proc_dointvec,
3558 },
3559 {
3560 .procname = "error_burst",
3561 .data = &ip_rt_error_burst,
3562 .maxlen = sizeof(int),
3563 .mode = 0644,
3564 .proc_handler = proc_dointvec,
3565 },
3566 {
3567 .procname = "gc_elasticity",
3568 .data = &ip_rt_gc_elasticity,
3569 .maxlen = sizeof(int),
3570 .mode = 0644,
3571 .proc_handler = proc_dointvec,
3572 },
3573 {
3574 .procname = "mtu_expires",
3575 .data = &ip_rt_mtu_expires,
3576 .maxlen = sizeof(int),
3577 .mode = 0644,
3578 .proc_handler = proc_dointvec_jiffies,
3579 },
3580 {
3581 .procname = "min_pmtu",
3582 .data = &ip_rt_min_pmtu,
3583 .maxlen = sizeof(int),
3584 .mode = 0644,
3585 .proc_handler = proc_dointvec_minmax,
3586 .extra1 = &ip_min_valid_pmtu,
3587 },
3588 {
3589 .procname = "min_adv_mss",
3590 .data = &ip_rt_min_advmss,
3591 .maxlen = sizeof(int),
3592 .mode = 0644,
3593 .proc_handler = proc_dointvec,
3594 },
3595 { }
3596 };
3597
3598 static const char ipv4_route_flush_procname[] = "flush";
3599
3600 static struct ctl_table ipv4_route_flush_table[] = {
3601 {
3602 .procname = ipv4_route_flush_procname,
3603 .maxlen = sizeof(int),
3604 .mode = 0200,
3605 .proc_handler = ipv4_sysctl_rtcache_flush,
3606 },
3607 { },
3608 };
3609
sysctl_route_net_init(struct net * net)3610 static __net_init int sysctl_route_net_init(struct net *net)
3611 {
3612 struct ctl_table *tbl;
3613
3614 tbl = ipv4_route_flush_table;
3615 if (!net_eq(net, &init_net)) {
3616 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL);
3617 if (!tbl)
3618 goto err_dup;
3619
3620 /* Don't export non-whitelisted sysctls to unprivileged users */
3621 if (net->user_ns != &init_user_ns) {
3622 if (tbl[0].procname != ipv4_route_flush_procname)
3623 tbl[0].procname = NULL;
3624 }
3625 }
3626 tbl[0].extra1 = net;
3627
3628 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl);
3629 if (!net->ipv4.route_hdr)
3630 goto err_reg;
3631 return 0;
3632
3633 err_reg:
3634 if (tbl != ipv4_route_flush_table)
3635 kfree(tbl);
3636 err_dup:
3637 return -ENOMEM;
3638 }
3639
sysctl_route_net_exit(struct net * net)3640 static __net_exit void sysctl_route_net_exit(struct net *net)
3641 {
3642 struct ctl_table *tbl;
3643
3644 tbl = net->ipv4.route_hdr->ctl_table_arg;
3645 unregister_net_sysctl_table(net->ipv4.route_hdr);
3646 BUG_ON(tbl == ipv4_route_flush_table);
3647 kfree(tbl);
3648 }
3649
3650 static __net_initdata struct pernet_operations sysctl_route_ops = {
3651 .init = sysctl_route_net_init,
3652 .exit = sysctl_route_net_exit,
3653 };
3654 #endif
3655
rt_genid_init(struct net * net)3656 static __net_init int rt_genid_init(struct net *net)
3657 {
3658 atomic_set(&net->ipv4.rt_genid, 0);
3659 atomic_set(&net->fnhe_genid, 0);
3660 atomic_set(&net->ipv4.dev_addr_genid, get_random_int());
3661 return 0;
3662 }
3663
3664 static __net_initdata struct pernet_operations rt_genid_ops = {
3665 .init = rt_genid_init,
3666 };
3667
ipv4_inetpeer_init(struct net * net)3668 static int __net_init ipv4_inetpeer_init(struct net *net)
3669 {
3670 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3671
3672 if (!bp)
3673 return -ENOMEM;
3674 inet_peer_base_init(bp);
3675 net->ipv4.peers = bp;
3676 return 0;
3677 }
3678
ipv4_inetpeer_exit(struct net * net)3679 static void __net_exit ipv4_inetpeer_exit(struct net *net)
3680 {
3681 struct inet_peer_base *bp = net->ipv4.peers;
3682
3683 net->ipv4.peers = NULL;
3684 inetpeer_invalidate_tree(bp);
3685 kfree(bp);
3686 }
3687
3688 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3689 .init = ipv4_inetpeer_init,
3690 .exit = ipv4_inetpeer_exit,
3691 };
3692
3693 #ifdef CONFIG_IP_ROUTE_CLASSID
3694 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3695 #endif /* CONFIG_IP_ROUTE_CLASSID */
3696
ip_rt_init(void)3697 int __init ip_rt_init(void)
3698 {
3699 void *idents_hash;
3700 int cpu;
3701
3702 /* For modern hosts, this will use 2 MB of memory */
3703 idents_hash = alloc_large_system_hash("IP idents",
3704 sizeof(*ip_idents) + sizeof(*ip_tstamps),
3705 0,
3706 16, /* one bucket per 64 KB */
3707 HASH_ZERO,
3708 NULL,
3709 &ip_idents_mask,
3710 2048,
3711 256*1024);
3712
3713 ip_idents = idents_hash;
3714
3715 prandom_bytes(ip_idents, (ip_idents_mask + 1) * sizeof(*ip_idents));
3716
3717 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3718
3719 for_each_possible_cpu(cpu) {
3720 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3721
3722 INIT_LIST_HEAD(&ul->head);
3723 spin_lock_init(&ul->lock);
3724 }
3725 #ifdef CONFIG_IP_ROUTE_CLASSID
3726 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3727 if (!ip_rt_acct)
3728 panic("IP: failed to allocate ip_rt_acct\n");
3729 #endif
3730
3731 ipv4_dst_ops.kmem_cachep =
3732 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0,
3733 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
3734
3735 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3736
3737 if (dst_entries_init(&ipv4_dst_ops) < 0)
3738 panic("IP: failed to allocate ipv4_dst_ops counter\n");
3739
3740 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
3741 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3742
3743 ipv4_dst_ops.gc_thresh = ~0;
3744 ip_rt_max_size = INT_MAX;
3745
3746 devinet_init();
3747 ip_fib_init();
3748
3749 if (ip_rt_proc_init())
3750 pr_err("Unable to create route proc files\n");
3751 #ifdef CONFIG_XFRM
3752 xfrm_init();
3753 xfrm4_init();
3754 #endif
3755 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3756 RTNL_FLAG_DOIT_UNLOCKED);
3757
3758 #ifdef CONFIG_SYSCTL
3759 register_pernet_subsys(&sysctl_route_ops);
3760 #endif
3761 register_pernet_subsys(&rt_genid_ops);
3762 register_pernet_subsys(&ipv4_inetpeer_ops);
3763 return 0;
3764 }
3765
3766 #ifdef CONFIG_SYSCTL
3767 /*
3768 * We really need to sanitize the damn ipv4 init order, then all
3769 * this nonsense will go away.
3770 */
ip_static_sysctl_init(void)3771 void __init ip_static_sysctl_init(void)
3772 {
3773 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3774 }
3775 #endif
3776