1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * ROUTE - implementation of the IP router.
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 * Alan Cox, <gw4pts@gw4pts.ampr.org>
12 * Linus Torvalds, <Linus.Torvalds@helsinki.fi>
13 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
14 *
15 * Fixes:
16 * Alan Cox : Verify area fixes.
17 * Alan Cox : cli() protects routing changes
18 * Rui Oliveira : ICMP routing table updates
19 * (rco@di.uminho.pt) Routing table insertion and update
20 * Linus Torvalds : Rewrote bits to be sensible
21 * Alan Cox : Added BSD route gw semantics
22 * Alan Cox : Super /proc >4K
23 * Alan Cox : MTU in route table
24 * Alan Cox : MSS actually. Also added the window
25 * clamper.
26 * Sam Lantinga : Fixed route matching in rt_del()
27 * Alan Cox : Routing cache support.
28 * Alan Cox : Removed compatibility cruft.
29 * Alan Cox : RTF_REJECT support.
30 * Alan Cox : TCP irtt support.
31 * Jonathan Naylor : Added Metric support.
32 * Miquel van Smoorenburg : BSD API fixes.
33 * Miquel van Smoorenburg : Metrics.
34 * Alan Cox : Use __u32 properly
35 * Alan Cox : Aligned routing errors more closely with BSD
36 * our system is still very different.
37 * Alan Cox : Faster /proc handling
38 * Alexey Kuznetsov : Massive rework to support tree based routing,
39 * routing caches and better behaviour.
40 *
41 * Olaf Erb : irtt wasn't being copied right.
42 * Bjorn Ekwall : Kerneld route support.
43 * Alan Cox : Multicast fixed (I hope)
44 * Pavel Krauz : Limited broadcast fixed
45 * Mike McLagan : Routing by source
46 * Alexey Kuznetsov : End of old history. Split to fib.c and
47 * route.c and rewritten from scratch.
48 * Andi Kleen : Load-limit warning messages.
49 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
50 * Vitaly E. Lavrov : Race condition in ip_route_input_slow.
51 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
52 * Vladimir V. Ivanov : IP rule info (flowid) is really useful.
53 * Marc Boucher : routing by fwmark
54 * Robert Olsson : Added rt_cache statistics
55 * Arnaldo C. Melo : Convert proc stuff to seq_file
56 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
57 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
58 * Ilia Sotnikov : Removed TOS from hash calculations
59 */
60
61#define pr_fmt(fmt) "IPv4: " fmt
62
63#include <linux/module.h>
64#include <linux/bitops.h>
65#include <linux/kernel.h>
66#include <linux/mm.h>
67#include <linux/memblock.h>
68#include <linux/socket.h>
69#include <linux/errno.h>
70#include <linux/in.h>
71#include <linux/inet.h>
72#include <linux/netdevice.h>
73#include <linux/proc_fs.h>
74#include <linux/init.h>
75#include <linux/skbuff.h>
76#include <linux/inetdevice.h>
77#include <linux/igmp.h>
78#include <linux/pkt_sched.h>
79#include <linux/mroute.h>
80#include <linux/netfilter_ipv4.h>
81#include <linux/random.h>
82#include <linux/rcupdate.h>
83#include <linux/slab.h>
84#include <linux/jhash.h>
85#include <net/dst.h>
86#include <net/dst_metadata.h>
87#include <net/inet_dscp.h>
88#include <net/net_namespace.h>
89#include <net/ip.h>
90#include <net/route.h>
91#include <net/inetpeer.h>
92#include <net/sock.h>
93#include <net/ip_fib.h>
94#include <net/nexthop.h>
95#include <net/tcp.h>
96#include <net/icmp.h>
97#include <net/xfrm.h>
98#include <net/lwtunnel.h>
99#include <net/netevent.h>
100#include <net/rtnetlink.h>
101#ifdef CONFIG_SYSCTL
102#include <linux/sysctl.h>
103#endif
104#include <net/secure_seq.h>
105#include <net/ip_tunnels.h>
106
107#include "fib_lookup.h"
108
109#define RT_FL_TOS(oldflp4) \
110 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
111
112#define RT_GC_TIMEOUT (300*HZ)
113
114#define DEFAULT_MIN_PMTU (512 + 20 + 20)
115#define DEFAULT_MTU_EXPIRES (10 * 60 * HZ)
116#define DEFAULT_MIN_ADVMSS 256
117static int ip_rt_max_size;
118static int ip_rt_redirect_number __read_mostly = 9;
119static int ip_rt_redirect_load __read_mostly = HZ / 50;
120static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
121static int ip_rt_error_cost __read_mostly = HZ;
122static int ip_rt_error_burst __read_mostly = 5 * HZ;
123
124static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
125
126/*
127 * Interface to generic destination cache.
128 */
129
130INDIRECT_CALLABLE_SCOPE
131struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
132static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
133INDIRECT_CALLABLE_SCOPE
134unsigned int ipv4_mtu(const struct dst_entry *dst);
135static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
136static void ipv4_link_failure(struct sk_buff *skb);
137static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
138 struct sk_buff *skb, u32 mtu,
139 bool confirm_neigh);
140static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
141 struct sk_buff *skb);
142static void ipv4_dst_destroy(struct dst_entry *dst);
143
144static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
145{
146 WARN_ON(1);
147 return NULL;
148}
149
150static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
151 struct sk_buff *skb,
152 const void *daddr);
153static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
154
155static struct dst_ops ipv4_dst_ops = {
156 .family = AF_INET,
157 .check = ipv4_dst_check,
158 .default_advmss = ipv4_default_advmss,
159 .mtu = ipv4_mtu,
160 .cow_metrics = ipv4_cow_metrics,
161 .destroy = ipv4_dst_destroy,
162 .negative_advice = ipv4_negative_advice,
163 .link_failure = ipv4_link_failure,
164 .update_pmtu = ip_rt_update_pmtu,
165 .redirect = ip_do_redirect,
166 .local_out = __ip_local_out,
167 .neigh_lookup = ipv4_neigh_lookup,
168 .confirm_neigh = ipv4_confirm_neigh,
169};
170
171#define ECN_OR_COST(class) TC_PRIO_##class
172
173const __u8 ip_tos2prio[16] = {
174 TC_PRIO_BESTEFFORT,
175 ECN_OR_COST(BESTEFFORT),
176 TC_PRIO_BESTEFFORT,
177 ECN_OR_COST(BESTEFFORT),
178 TC_PRIO_BULK,
179 ECN_OR_COST(BULK),
180 TC_PRIO_BULK,
181 ECN_OR_COST(BULK),
182 TC_PRIO_INTERACTIVE,
183 ECN_OR_COST(INTERACTIVE),
184 TC_PRIO_INTERACTIVE,
185 ECN_OR_COST(INTERACTIVE),
186 TC_PRIO_INTERACTIVE_BULK,
187 ECN_OR_COST(INTERACTIVE_BULK),
188 TC_PRIO_INTERACTIVE_BULK,
189 ECN_OR_COST(INTERACTIVE_BULK)
190};
191EXPORT_SYMBOL(ip_tos2prio);
192
193static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
194#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
195
196#ifdef CONFIG_PROC_FS
197static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
198{
199 if (*pos)
200 return NULL;
201 return SEQ_START_TOKEN;
202}
203
204static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
205{
206 ++*pos;
207 return NULL;
208}
209
210static void rt_cache_seq_stop(struct seq_file *seq, void *v)
211{
212}
213
214static int rt_cache_seq_show(struct seq_file *seq, void *v)
215{
216 if (v == SEQ_START_TOKEN)
217 seq_printf(m: seq, fmt: "%-127s\n",
218 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
219 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
220 "HHUptod\tSpecDst");
221 return 0;
222}
223
224static const struct seq_operations rt_cache_seq_ops = {
225 .start = rt_cache_seq_start,
226 .next = rt_cache_seq_next,
227 .stop = rt_cache_seq_stop,
228 .show = rt_cache_seq_show,
229};
230
231static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
232{
233 int cpu;
234
235 if (*pos == 0)
236 return SEQ_START_TOKEN;
237
238 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
239 if (!cpu_possible(cpu))
240 continue;
241 *pos = cpu+1;
242 return &per_cpu(rt_cache_stat, cpu);
243 }
244 return NULL;
245}
246
247static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
248{
249 int cpu;
250
251 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
252 if (!cpu_possible(cpu))
253 continue;
254 *pos = cpu+1;
255 return &per_cpu(rt_cache_stat, cpu);
256 }
257 (*pos)++;
258 return NULL;
259
260}
261
262static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
263{
264
265}
266
267static int rt_cpu_seq_show(struct seq_file *seq, void *v)
268{
269 struct rt_cache_stat *st = v;
270
271 if (v == SEQ_START_TOKEN) {
272 seq_puts(m: seq, s: "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");
273 return 0;
274 }
275
276 seq_printf(m: seq, fmt: "%08x %08x %08x %08x %08x %08x %08x "
277 "%08x %08x %08x %08x %08x %08x "
278 "%08x %08x %08x %08x\n",
279 dst_entries_get_slow(dst: &ipv4_dst_ops),
280 0, /* st->in_hit */
281 st->in_slow_tot,
282 st->in_slow_mc,
283 st->in_no_route,
284 st->in_brd,
285 st->in_martian_dst,
286 st->in_martian_src,
287
288 0, /* st->out_hit */
289 st->out_slow_tot,
290 st->out_slow_mc,
291
292 0, /* st->gc_total */
293 0, /* st->gc_ignored */
294 0, /* st->gc_goal_miss */
295 0, /* st->gc_dst_overflow */
296 0, /* st->in_hlist_search */
297 0 /* st->out_hlist_search */
298 );
299 return 0;
300}
301
302static const struct seq_operations rt_cpu_seq_ops = {
303 .start = rt_cpu_seq_start,
304 .next = rt_cpu_seq_next,
305 .stop = rt_cpu_seq_stop,
306 .show = rt_cpu_seq_show,
307};
308
309#ifdef CONFIG_IP_ROUTE_CLASSID
310static int rt_acct_proc_show(struct seq_file *m, void *v)
311{
312 struct ip_rt_acct *dst, *src;
313 unsigned int i, j;
314
315 dst = kcalloc(n: 256, size: sizeof(struct ip_rt_acct), GFP_KERNEL);
316 if (!dst)
317 return -ENOMEM;
318
319 for_each_possible_cpu(i) {
320 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
321 for (j = 0; j < 256; j++) {
322 dst[j].o_bytes += src[j].o_bytes;
323 dst[j].o_packets += src[j].o_packets;
324 dst[j].i_bytes += src[j].i_bytes;
325 dst[j].i_packets += src[j].i_packets;
326 }
327 }
328
329 seq_write(seq: m, data: dst, len: 256 * sizeof(struct ip_rt_acct));
330 kfree(objp: dst);
331 return 0;
332}
333#endif
334
335static int __net_init ip_rt_do_proc_init(struct net *net)
336{
337 struct proc_dir_entry *pde;
338
339 pde = proc_create_seq("rt_cache", 0444, net->proc_net,
340 &rt_cache_seq_ops);
341 if (!pde)
342 goto err1;
343
344 pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
345 &rt_cpu_seq_ops);
346 if (!pde)
347 goto err2;
348
349#ifdef CONFIG_IP_ROUTE_CLASSID
350 pde = proc_create_single("rt_acct", 0, net->proc_net,
351 rt_acct_proc_show);
352 if (!pde)
353 goto err3;
354#endif
355 return 0;
356
357#ifdef CONFIG_IP_ROUTE_CLASSID
358err3:
359 remove_proc_entry("rt_cache", net->proc_net_stat);
360#endif
361err2:
362 remove_proc_entry("rt_cache", net->proc_net);
363err1:
364 return -ENOMEM;
365}
366
367static void __net_exit ip_rt_do_proc_exit(struct net *net)
368{
369 remove_proc_entry("rt_cache", net->proc_net_stat);
370 remove_proc_entry("rt_cache", net->proc_net);
371#ifdef CONFIG_IP_ROUTE_CLASSID
372 remove_proc_entry("rt_acct", net->proc_net);
373#endif
374}
375
376static struct pernet_operations ip_rt_proc_ops __net_initdata = {
377 .init = ip_rt_do_proc_init,
378 .exit = ip_rt_do_proc_exit,
379};
380
381static int __init ip_rt_proc_init(void)
382{
383 return register_pernet_subsys(&ip_rt_proc_ops);
384}
385
386#else
387static inline int ip_rt_proc_init(void)
388{
389 return 0;
390}
391#endif /* CONFIG_PROC_FS */
392
393static inline bool rt_is_expired(const struct rtable *rth)
394{
395 return rth->rt_genid != rt_genid_ipv4(net: dev_net(dev: rth->dst.dev));
396}
397
398void rt_cache_flush(struct net *net)
399{
400 rt_genid_bump_ipv4(net);
401}
402
403static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
404 struct sk_buff *skb,
405 const void *daddr)
406{
407 const struct rtable *rt = container_of(dst, struct rtable, dst);
408 struct net_device *dev = dst->dev;
409 struct neighbour *n;
410
411 rcu_read_lock();
412
413 if (likely(rt->rt_gw_family == AF_INET)) {
414 n = ip_neigh_gw4(dev, daddr: rt->rt_gw4);
415 } else if (rt->rt_gw_family == AF_INET6) {
416 n = ip_neigh_gw6(dev, addr: &rt->rt_gw6);
417 } else {
418 __be32 pkey;
419
420 pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
421 n = ip_neigh_gw4(dev, daddr: pkey);
422 }
423
424 if (!IS_ERR(ptr: n) && !refcount_inc_not_zero(r: &n->refcnt))
425 n = NULL;
426
427 rcu_read_unlock();
428
429 return n;
430}
431
432static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
433{
434 const struct rtable *rt = container_of(dst, struct rtable, dst);
435 struct net_device *dev = dst->dev;
436 const __be32 *pkey = daddr;
437
438 if (rt->rt_gw_family == AF_INET) {
439 pkey = (const __be32 *)&rt->rt_gw4;
440 } else if (rt->rt_gw_family == AF_INET6) {
441 return __ipv6_confirm_neigh_stub(dev, pkey: &rt->rt_gw6);
442 } else if (!daddr ||
443 (rt->rt_flags &
444 (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
445 return;
446 }
447 __ipv4_confirm_neigh(dev, key: *(__force u32 *)pkey);
448}
449
450/* Hash tables of size 2048..262144 depending on RAM size.
451 * Each bucket uses 8 bytes.
452 */
453static u32 ip_idents_mask __read_mostly;
454static atomic_t *ip_idents __read_mostly;
455static u32 *ip_tstamps __read_mostly;
456
457/* In order to protect privacy, we add a perturbation to identifiers
458 * if one generator is seldom used. This makes hard for an attacker
459 * to infer how many packets were sent between two points in time.
460 */
461static u32 ip_idents_reserve(u32 hash, int segs)
462{
463 u32 bucket, old, now = (u32)jiffies;
464 atomic_t *p_id;
465 u32 *p_tstamp;
466 u32 delta = 0;
467
468 bucket = hash & ip_idents_mask;
469 p_tstamp = ip_tstamps + bucket;
470 p_id = ip_idents + bucket;
471 old = READ_ONCE(*p_tstamp);
472
473 if (old != now && cmpxchg(p_tstamp, old, now) == old)
474 delta = get_random_u32_below(ceil: now - old);
475
476 /* If UBSAN reports an error there, please make sure your compiler
477 * supports -fno-strict-overflow before reporting it that was a bug
478 * in UBSAN, and it has been fixed in GCC-8.
479 */
480 return atomic_add_return(i: segs + delta, v: p_id) - segs;
481}
482
483void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
484{
485 u32 hash, id;
486
487 /* Note the following code is not safe, but this is okay. */
488 if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
489 get_random_bytes(buf: &net->ipv4.ip_id_key,
490 len: sizeof(net->ipv4.ip_id_key));
491
492 hash = siphash_3u32(a: (__force u32)iph->daddr,
493 b: (__force u32)iph->saddr,
494 c: iph->protocol,
495 key: &net->ipv4.ip_id_key);
496 id = ip_idents_reserve(hash, segs);
497 iph->id = htons(id);
498}
499EXPORT_SYMBOL(__ip_select_ident);
500
501static void ip_rt_fix_tos(struct flowi4 *fl4)
502{
503 __u8 tos = RT_FL_TOS(fl4);
504
505 fl4->flowi4_tos = tos & IPTOS_RT_MASK;
506 if (tos & RTO_ONLINK)
507 fl4->flowi4_scope = RT_SCOPE_LINK;
508}
509
510static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
511 const struct sock *sk, const struct iphdr *iph,
512 int oif, __u8 tos, u8 prot, u32 mark,
513 int flow_flags)
514{
515 __u8 scope = RT_SCOPE_UNIVERSE;
516
517 if (sk) {
518 oif = sk->sk_bound_dev_if;
519 mark = READ_ONCE(sk->sk_mark);
520 tos = ip_sock_rt_tos(sk);
521 scope = ip_sock_rt_scope(sk);
522 prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW :
523 sk->sk_protocol;
524 }
525
526 flowi4_init_output(fl4, oif, mark, tos: tos & IPTOS_RT_MASK, scope,
527 proto: prot, flags: flow_flags, daddr: iph->daddr, saddr: iph->saddr, dport: 0, sport: 0,
528 uid: sock_net_uid(net, sk));
529}
530
531static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
532 const struct sock *sk)
533{
534 const struct net *net = dev_net(dev: skb->dev);
535 const struct iphdr *iph = ip_hdr(skb);
536 int oif = skb->dev->ifindex;
537 u8 prot = iph->protocol;
538 u32 mark = skb->mark;
539 __u8 tos = iph->tos;
540
541 __build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, flow_flags: 0);
542}
543
544static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
545{
546 const struct inet_sock *inet = inet_sk(sk);
547 const struct ip_options_rcu *inet_opt;
548 __be32 daddr = inet->inet_daddr;
549
550 rcu_read_lock();
551 inet_opt = rcu_dereference(inet->inet_opt);
552 if (inet_opt && inet_opt->opt.srr)
553 daddr = inet_opt->opt.faddr;
554 flowi4_init_output(fl4, oif: sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark),
555 tos: ip_sock_rt_tos(sk) & IPTOS_RT_MASK,
556 scope: ip_sock_rt_scope(sk),
557 inet_test_bit(HDRINCL, sk) ?
558 IPPROTO_RAW : sk->sk_protocol,
559 flags: inet_sk_flowi_flags(sk),
560 daddr, saddr: inet->inet_saddr, dport: 0, sport: 0, uid: sk->sk_uid);
561 rcu_read_unlock();
562}
563
564static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
565 const struct sk_buff *skb)
566{
567 if (skb)
568 build_skb_flow_key(fl4, skb, sk);
569 else
570 build_sk_flow_key(fl4, sk);
571}
572
573static DEFINE_SPINLOCK(fnhe_lock);
574
575static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
576{
577 struct rtable *rt;
578
579 rt = rcu_dereference(fnhe->fnhe_rth_input);
580 if (rt) {
581 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
582 dst_dev_put(dst: &rt->dst);
583 dst_release(dst: &rt->dst);
584 }
585 rt = rcu_dereference(fnhe->fnhe_rth_output);
586 if (rt) {
587 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
588 dst_dev_put(dst: &rt->dst);
589 dst_release(dst: &rt->dst);
590 }
591}
592
593static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
594{
595 struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
596 struct fib_nh_exception *fnhe, *oldest = NULL;
597
598 for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
599 fnhe = rcu_dereference_protected(*fnhe_p,
600 lockdep_is_held(&fnhe_lock));
601 if (!fnhe)
602 break;
603 if (!oldest ||
604 time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
605 oldest = fnhe;
606 oldest_p = fnhe_p;
607 }
608 }
609 fnhe_flush_routes(fnhe: oldest);
610 *oldest_p = oldest->fnhe_next;
611 kfree_rcu(oldest, rcu);
612}
613
614static u32 fnhe_hashfun(__be32 daddr)
615{
616 static siphash_aligned_key_t fnhe_hash_key;
617 u64 hval;
618
619 net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
620 hval = siphash_1u32(a: (__force u32)daddr, key: &fnhe_hash_key);
621 return hash_64(val: hval, FNHE_HASH_SHIFT);
622}
623
624static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
625{
626 rt->rt_pmtu = fnhe->fnhe_pmtu;
627 rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
628 rt->dst.expires = fnhe->fnhe_expires;
629
630 if (fnhe->fnhe_gw) {
631 rt->rt_flags |= RTCF_REDIRECTED;
632 rt->rt_uses_gateway = 1;
633 rt->rt_gw_family = AF_INET;
634 rt->rt_gw4 = fnhe->fnhe_gw;
635 }
636}
637
638static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
639 __be32 gw, u32 pmtu, bool lock,
640 unsigned long expires)
641{
642 struct fnhe_hash_bucket *hash;
643 struct fib_nh_exception *fnhe;
644 struct rtable *rt;
645 u32 genid, hval;
646 unsigned int i;
647 int depth;
648
649 genid = fnhe_genid(net: dev_net(dev: nhc->nhc_dev));
650 hval = fnhe_hashfun(daddr);
651
652 spin_lock_bh(lock: &fnhe_lock);
653
654 hash = rcu_dereference(nhc->nhc_exceptions);
655 if (!hash) {
656 hash = kcalloc(FNHE_HASH_SIZE, size: sizeof(*hash), GFP_ATOMIC);
657 if (!hash)
658 goto out_unlock;
659 rcu_assign_pointer(nhc->nhc_exceptions, hash);
660 }
661
662 hash += hval;
663
664 depth = 0;
665 for (fnhe = rcu_dereference(hash->chain); fnhe;
666 fnhe = rcu_dereference(fnhe->fnhe_next)) {
667 if (fnhe->fnhe_daddr == daddr)
668 break;
669 depth++;
670 }
671
672 if (fnhe) {
673 if (fnhe->fnhe_genid != genid)
674 fnhe->fnhe_genid = genid;
675 if (gw)
676 fnhe->fnhe_gw = gw;
677 if (pmtu) {
678 fnhe->fnhe_pmtu = pmtu;
679 fnhe->fnhe_mtu_locked = lock;
680 }
681 fnhe->fnhe_expires = max(1UL, expires);
682 /* Update all cached dsts too */
683 rt = rcu_dereference(fnhe->fnhe_rth_input);
684 if (rt)
685 fill_route_from_fnhe(rt, fnhe);
686 rt = rcu_dereference(fnhe->fnhe_rth_output);
687 if (rt)
688 fill_route_from_fnhe(rt, fnhe);
689 } else {
690 /* Randomize max depth to avoid some side channels attacks. */
691 int max_depth = FNHE_RECLAIM_DEPTH +
692 get_random_u32_below(FNHE_RECLAIM_DEPTH);
693
694 while (depth > max_depth) {
695 fnhe_remove_oldest(hash);
696 depth--;
697 }
698
699 fnhe = kzalloc(size: sizeof(*fnhe), GFP_ATOMIC);
700 if (!fnhe)
701 goto out_unlock;
702
703 fnhe->fnhe_next = hash->chain;
704
705 fnhe->fnhe_genid = genid;
706 fnhe->fnhe_daddr = daddr;
707 fnhe->fnhe_gw = gw;
708 fnhe->fnhe_pmtu = pmtu;
709 fnhe->fnhe_mtu_locked = lock;
710 fnhe->fnhe_expires = max(1UL, expires);
711
712 rcu_assign_pointer(hash->chain, fnhe);
713
714 /* Exception created; mark the cached routes for the nexthop
715 * stale, so anyone caching it rechecks if this exception
716 * applies to them.
717 */
718 rt = rcu_dereference(nhc->nhc_rth_input);
719 if (rt)
720 rt->dst.obsolete = DST_OBSOLETE_KILL;
721
722 for_each_possible_cpu(i) {
723 struct rtable __rcu **prt;
724
725 prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
726 rt = rcu_dereference(*prt);
727 if (rt)
728 rt->dst.obsolete = DST_OBSOLETE_KILL;
729 }
730 }
731
732 fnhe->fnhe_stamp = jiffies;
733
734out_unlock:
735 spin_unlock_bh(lock: &fnhe_lock);
736}
737
738static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
739 bool kill_route)
740{
741 __be32 new_gw = icmp_hdr(skb)->un.gateway;
742 __be32 old_gw = ip_hdr(skb)->saddr;
743 struct net_device *dev = skb->dev;
744 struct in_device *in_dev;
745 struct fib_result res;
746 struct neighbour *n;
747 struct net *net;
748
749 switch (icmp_hdr(skb)->code & 7) {
750 case ICMP_REDIR_NET:
751 case ICMP_REDIR_NETTOS:
752 case ICMP_REDIR_HOST:
753 case ICMP_REDIR_HOSTTOS:
754 break;
755
756 default:
757 return;
758 }
759
760 if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
761 return;
762
763 in_dev = __in_dev_get_rcu(dev);
764 if (!in_dev)
765 return;
766
767 net = dev_net(dev);
768 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
769 ipv4_is_multicast(addr: new_gw) || ipv4_is_lbcast(addr: new_gw) ||
770 ipv4_is_zeronet(addr: new_gw))
771 goto reject_redirect;
772
773 if (!IN_DEV_SHARED_MEDIA(in_dev)) {
774 if (!inet_addr_onlink(in_dev, a: new_gw, b: old_gw))
775 goto reject_redirect;
776 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(gw: new_gw, dev))
777 goto reject_redirect;
778 } else {
779 if (inet_addr_type(net, addr: new_gw) != RTN_UNICAST)
780 goto reject_redirect;
781 }
782
783 n = __ipv4_neigh_lookup(dev: rt->dst.dev, key: (__force u32)new_gw);
784 if (!n)
785 n = neigh_create(tbl: &arp_tbl, pkey: &new_gw, dev: rt->dst.dev);
786 if (!IS_ERR(ptr: n)) {
787 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
788 neigh_event_send(neigh: n, NULL);
789 } else {
790 if (fib_lookup(net, flp: fl4, res: &res, flags: 0) == 0) {
791 struct fib_nh_common *nhc;
792
793 fib_select_path(net, res: &res, fl4, skb);
794 nhc = FIB_RES_NHC(res);
795 update_or_create_fnhe(nhc, daddr: fl4->daddr, gw: new_gw,
796 pmtu: 0, lock: false,
797 expires: jiffies + ip_rt_gc_timeout);
798 }
799 if (kill_route)
800 rt->dst.obsolete = DST_OBSOLETE_KILL;
801 call_netevent_notifiers(val: NETEVENT_NEIGH_UPDATE, v: n);
802 }
803 neigh_release(neigh: n);
804 }
805 return;
806
807reject_redirect:
808#ifdef CONFIG_IP_ROUTE_VERBOSE
809 if (IN_DEV_LOG_MARTIANS(in_dev)) {
810 const struct iphdr *iph = (const struct iphdr *) skb->data;
811 __be32 daddr = iph->daddr;
812 __be32 saddr = iph->saddr;
813
814 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
815 " Advised path = %pI4 -> %pI4\n",
816 &old_gw, dev->name, &new_gw,
817 &saddr, &daddr);
818 }
819#endif
820 ;
821}
822
823static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
824{
825 struct rtable *rt;
826 struct flowi4 fl4;
827 const struct iphdr *iph = (const struct iphdr *) skb->data;
828 struct net *net = dev_net(dev: skb->dev);
829 int oif = skb->dev->ifindex;
830 u8 prot = iph->protocol;
831 u32 mark = skb->mark;
832 __u8 tos = iph->tos;
833
834 rt = (struct rtable *) dst;
835
836 __build_flow_key(net, fl4: &fl4, sk, iph, oif, tos, prot, mark, flow_flags: 0);
837 __ip_do_redirect(rt, skb, fl4: &fl4, kill_route: true);
838}
839
840static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
841{
842 struct rtable *rt = (struct rtable *)dst;
843 struct dst_entry *ret = dst;
844
845 if (rt) {
846 if (dst->obsolete > 0) {
847 ip_rt_put(rt);
848 ret = NULL;
849 } else if ((rt->rt_flags & RTCF_REDIRECTED) ||
850 rt->dst.expires) {
851 ip_rt_put(rt);
852 ret = NULL;
853 }
854 }
855 return ret;
856}
857
858/*
859 * Algorithm:
860 * 1. The first ip_rt_redirect_number redirects are sent
861 * with exponential backoff, then we stop sending them at all,
862 * assuming that the host ignores our redirects.
863 * 2. If we did not see packets requiring redirects
864 * during ip_rt_redirect_silence, we assume that the host
865 * forgot redirected route and start to send redirects again.
866 *
867 * This algorithm is much cheaper and more intelligent than dumb load limiting
868 * in icmp.c.
869 *
870 * NOTE. Do not forget to inhibit load limiting for redirects (redundant)
871 * and "frag. need" (breaks PMTU discovery) in icmp.c.
872 */
873
874void ip_rt_send_redirect(struct sk_buff *skb)
875{
876 struct rtable *rt = skb_rtable(skb);
877 struct in_device *in_dev;
878 struct inet_peer *peer;
879 struct net *net;
880 int log_martians;
881 int vif;
882
883 rcu_read_lock();
884 in_dev = __in_dev_get_rcu(dev: rt->dst.dev);
885 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
886 rcu_read_unlock();
887 return;
888 }
889 log_martians = IN_DEV_LOG_MARTIANS(in_dev);
890 vif = l3mdev_master_ifindex_rcu(dev: rt->dst.dev);
891 rcu_read_unlock();
892
893 net = dev_net(dev: rt->dst.dev);
894 peer = inet_getpeer_v4(base: net->ipv4.peers, v4daddr: ip_hdr(skb)->saddr, vif, create: 1);
895 if (!peer) {
896 icmp_send(skb_in: skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
897 info: rt_nexthop(rt, daddr: ip_hdr(skb)->daddr));
898 return;
899 }
900
901 /* No redirected packets during ip_rt_redirect_silence;
902 * reset the algorithm.
903 */
904 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
905 peer->rate_tokens = 0;
906 peer->n_redirects = 0;
907 }
908
909 /* Too many ignored redirects; do not send anything
910 * set dst.rate_last to the last seen redirected packet.
911 */
912 if (peer->n_redirects >= ip_rt_redirect_number) {
913 peer->rate_last = jiffies;
914 goto out_put_peer;
915 }
916
917 /* Check for load limit; set rate_last to the latest sent
918 * redirect.
919 */
920 if (peer->n_redirects == 0 ||
921 time_after(jiffies,
922 (peer->rate_last +
923 (ip_rt_redirect_load << peer->n_redirects)))) {
924 __be32 gw = rt_nexthop(rt, daddr: ip_hdr(skb)->daddr);
925
926 icmp_send(skb_in: skb, ICMP_REDIRECT, ICMP_REDIR_HOST, info: gw);
927 peer->rate_last = jiffies;
928 ++peer->n_redirects;
929 if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians &&
930 peer->n_redirects == ip_rt_redirect_number)
931 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
932 &ip_hdr(skb)->saddr, inet_iif(skb),
933 &ip_hdr(skb)->daddr, &gw);
934 }
935out_put_peer:
936 inet_putpeer(p: peer);
937}
938
939static int ip_error(struct sk_buff *skb)
940{
941 struct rtable *rt = skb_rtable(skb);
942 struct net_device *dev = skb->dev;
943 struct in_device *in_dev;
944 struct inet_peer *peer;
945 unsigned long now;
946 struct net *net;
947 SKB_DR(reason);
948 bool send;
949 int code;
950
951 if (netif_is_l3_master(dev: skb->dev)) {
952 dev = __dev_get_by_index(net: dev_net(dev: skb->dev), IPCB(skb)->iif);
953 if (!dev)
954 goto out;
955 }
956
957 in_dev = __in_dev_get_rcu(dev);
958
959 /* IP on this device is disabled. */
960 if (!in_dev)
961 goto out;
962
963 net = dev_net(dev: rt->dst.dev);
964 if (!IN_DEV_FORWARD(in_dev)) {
965 switch (rt->dst.error) {
966 case EHOSTUNREACH:
967 SKB_DR_SET(reason, IP_INADDRERRORS);
968 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
969 break;
970
971 case ENETUNREACH:
972 SKB_DR_SET(reason, IP_INNOROUTES);
973 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
974 break;
975 }
976 goto out;
977 }
978
979 switch (rt->dst.error) {
980 case EINVAL:
981 default:
982 goto out;
983 case EHOSTUNREACH:
984 code = ICMP_HOST_UNREACH;
985 break;
986 case ENETUNREACH:
987 code = ICMP_NET_UNREACH;
988 SKB_DR_SET(reason, IP_INNOROUTES);
989 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
990 break;
991 case EACCES:
992 code = ICMP_PKT_FILTERED;
993 break;
994 }
995
996 peer = inet_getpeer_v4(base: net->ipv4.peers, v4daddr: ip_hdr(skb)->saddr,
997 vif: l3mdev_master_ifindex(dev: skb->dev), create: 1);
998
999 send = true;
1000 if (peer) {
1001 now = jiffies;
1002 peer->rate_tokens += now - peer->rate_last;
1003 if (peer->rate_tokens > ip_rt_error_burst)
1004 peer->rate_tokens = ip_rt_error_burst;
1005 peer->rate_last = now;
1006 if (peer->rate_tokens >= ip_rt_error_cost)
1007 peer->rate_tokens -= ip_rt_error_cost;
1008 else
1009 send = false;
1010 inet_putpeer(p: peer);
1011 }
1012 if (send)
1013 icmp_send(skb_in: skb, ICMP_DEST_UNREACH, code, info: 0);
1014
1015out: kfree_skb_reason(skb, reason);
1016 return 0;
1017}
1018
1019static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1020{
1021 struct dst_entry *dst = &rt->dst;
1022 struct net *net = dev_net(dev: dst->dev);
1023 struct fib_result res;
1024 bool lock = false;
1025 u32 old_mtu;
1026
1027 if (ip_mtu_locked(dst))
1028 return;
1029
1030 old_mtu = ipv4_mtu(dst);
1031 if (old_mtu < mtu)
1032 return;
1033
1034 if (mtu < net->ipv4.ip_rt_min_pmtu) {
1035 lock = true;
1036 mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
1037 }
1038
1039 if (rt->rt_pmtu == mtu && !lock &&
1040 time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
1041 return;
1042
1043 rcu_read_lock();
1044 if (fib_lookup(net, flp: fl4, res: &res, flags: 0) == 0) {
1045 struct fib_nh_common *nhc;
1046
1047 fib_select_path(net, res: &res, fl4, NULL);
1048 nhc = FIB_RES_NHC(res);
1049 update_or_create_fnhe(nhc, daddr: fl4->daddr, gw: 0, pmtu: mtu, lock,
1050 expires: jiffies + net->ipv4.ip_rt_mtu_expires);
1051 }
1052 rcu_read_unlock();
1053}
1054
1055static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1056 struct sk_buff *skb, u32 mtu,
1057 bool confirm_neigh)
1058{
1059 struct rtable *rt = (struct rtable *) dst;
1060 struct flowi4 fl4;
1061
1062 ip_rt_build_flow_key(fl4: &fl4, sk, skb);
1063
1064 /* Don't make lookup fail for bridged encapsulations */
1065 if (skb && netif_is_any_bridge_port(dev: skb->dev))
1066 fl4.flowi4_oif = 0;
1067
1068 __ip_rt_update_pmtu(rt, fl4: &fl4, mtu);
1069}
1070
1071void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1072 int oif, u8 protocol)
1073{
1074 const struct iphdr *iph = (const struct iphdr *)skb->data;
1075 struct flowi4 fl4;
1076 struct rtable *rt;
1077 u32 mark = IP4_REPLY_MARK(net, skb->mark);
1078
1079 __build_flow_key(net, fl4: &fl4, NULL, iph, oif, tos: iph->tos, prot: protocol, mark,
1080 flow_flags: 0);
1081 rt = __ip_route_output_key(net, flp: &fl4);
1082 if (!IS_ERR(ptr: rt)) {
1083 __ip_rt_update_pmtu(rt, fl4: &fl4, mtu);
1084 ip_rt_put(rt);
1085 }
1086}
1087EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1088
1089static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1090{
1091 const struct iphdr *iph = (const struct iphdr *)skb->data;
1092 struct flowi4 fl4;
1093 struct rtable *rt;
1094
1095 __build_flow_key(net: sock_net(sk), fl4: &fl4, sk, iph, oif: 0, tos: 0, prot: 0, mark: 0, flow_flags: 0);
1096
1097 if (!fl4.flowi4_mark)
1098 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1099
1100 rt = __ip_route_output_key(net: sock_net(sk), flp: &fl4);
1101 if (!IS_ERR(ptr: rt)) {
1102 __ip_rt_update_pmtu(rt, fl4: &fl4, mtu);
1103 ip_rt_put(rt);
1104 }
1105}
1106
1107void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1108{
1109 const struct iphdr *iph = (const struct iphdr *)skb->data;
1110 struct flowi4 fl4;
1111 struct rtable *rt;
1112 struct dst_entry *odst = NULL;
1113 bool new = false;
1114 struct net *net = sock_net(sk);
1115
1116 bh_lock_sock(sk);
1117
1118 if (!ip_sk_accept_pmtu(sk))
1119 goto out;
1120
1121 odst = sk_dst_get(sk);
1122
1123 if (sock_owned_by_user(sk) || !odst) {
1124 __ipv4_sk_update_pmtu(skb, sk, mtu);
1125 goto out;
1126 }
1127
1128 __build_flow_key(net, fl4: &fl4, sk, iph, oif: 0, tos: 0, prot: 0, mark: 0, flow_flags: 0);
1129
1130 rt = (struct rtable *)odst;
1131 if (odst->obsolete && !odst->ops->check(odst, 0)) {
1132 rt = ip_route_output_flow(sock_net(sk), flp: &fl4, sk);
1133 if (IS_ERR(ptr: rt))
1134 goto out;
1135
1136 new = true;
1137 }
1138
1139 __ip_rt_update_pmtu(rt: (struct rtable *)xfrm_dst_path(dst: &rt->dst), fl4: &fl4, mtu);
1140
1141 if (!dst_check(dst: &rt->dst, cookie: 0)) {
1142 if (new)
1143 dst_release(dst: &rt->dst);
1144
1145 rt = ip_route_output_flow(sock_net(sk), flp: &fl4, sk);
1146 if (IS_ERR(ptr: rt))
1147 goto out;
1148
1149 new = true;
1150 }
1151
1152 if (new)
1153 sk_dst_set(sk, dst: &rt->dst);
1154
1155out:
1156 bh_unlock_sock(sk);
1157 dst_release(dst: odst);
1158}
1159EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1160
1161void ipv4_redirect(struct sk_buff *skb, struct net *net,
1162 int oif, u8 protocol)
1163{
1164 const struct iphdr *iph = (const struct iphdr *)skb->data;
1165 struct flowi4 fl4;
1166 struct rtable *rt;
1167
1168 __build_flow_key(net, fl4: &fl4, NULL, iph, oif, tos: iph->tos, prot: protocol, mark: 0, flow_flags: 0);
1169 rt = __ip_route_output_key(net, flp: &fl4);
1170 if (!IS_ERR(ptr: rt)) {
1171 __ip_do_redirect(rt, skb, fl4: &fl4, kill_route: false);
1172 ip_rt_put(rt);
1173 }
1174}
1175EXPORT_SYMBOL_GPL(ipv4_redirect);
1176
1177void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1178{
1179 const struct iphdr *iph = (const struct iphdr *)skb->data;
1180 struct flowi4 fl4;
1181 struct rtable *rt;
1182 struct net *net = sock_net(sk);
1183
1184 __build_flow_key(net, fl4: &fl4, sk, iph, oif: 0, tos: 0, prot: 0, mark: 0, flow_flags: 0);
1185 rt = __ip_route_output_key(net, flp: &fl4);
1186 if (!IS_ERR(ptr: rt)) {
1187 __ip_do_redirect(rt, skb, fl4: &fl4, kill_route: false);
1188 ip_rt_put(rt);
1189 }
1190}
1191EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1192
1193INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1194 u32 cookie)
1195{
1196 struct rtable *rt = (struct rtable *) dst;
1197
1198 /* All IPV4 dsts are created with ->obsolete set to the value
1199 * DST_OBSOLETE_FORCE_CHK which forces validation calls down
1200 * into this function always.
1201 *
1202 * When a PMTU/redirect information update invalidates a route,
1203 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1204 * DST_OBSOLETE_DEAD.
1205 */
1206 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rth: rt))
1207 return NULL;
1208 return dst;
1209}
1210EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1211
1212static void ipv4_send_dest_unreach(struct sk_buff *skb)
1213{
1214 struct net_device *dev;
1215 struct ip_options opt;
1216 int res;
1217
1218 /* Recompile ip options since IPCB may not be valid anymore.
1219 * Also check we have a reasonable ipv4 header.
1220 */
1221 if (!pskb_network_may_pull(skb, len: sizeof(struct iphdr)) ||
1222 ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1223 return;
1224
1225 memset(&opt, 0, sizeof(opt));
1226 if (ip_hdr(skb)->ihl > 5) {
1227 if (!pskb_network_may_pull(skb, len: ip_hdr(skb)->ihl * 4))
1228 return;
1229 opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1230
1231 rcu_read_lock();
1232 dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
1233 res = __ip_options_compile(net: dev_net(dev), opt: &opt, skb, NULL);
1234 rcu_read_unlock();
1235
1236 if (res)
1237 return;
1238 }
1239 __icmp_send(skb_in: skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, info: 0, opt: &opt);
1240}
1241
1242static void ipv4_link_failure(struct sk_buff *skb)
1243{
1244 struct rtable *rt;
1245
1246 ipv4_send_dest_unreach(skb);
1247
1248 rt = skb_rtable(skb);
1249 if (rt)
1250 dst_set_expires(dst: &rt->dst, timeout: 0);
1251}
1252
1253static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1254{
1255 pr_debug("%s: %pI4 -> %pI4, %s\n",
1256 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1257 skb->dev ? skb->dev->name : "?");
1258 kfree_skb(skb);
1259 WARN_ON(1);
1260 return 0;
1261}
1262
1263/*
1264 * We do not cache source address of outgoing interface,
1265 * because it is used only by IP RR, TS and SRR options,
1266 * so that it out of fast path.
1267 *
1268 * BTW remember: "addr" is allowed to be not aligned
1269 * in IP options!
1270 */
1271
1272void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1273{
1274 __be32 src;
1275
1276 if (rt_is_output_route(rt))
1277 src = ip_hdr(skb)->saddr;
1278 else {
1279 struct fib_result res;
1280 struct iphdr *iph = ip_hdr(skb);
1281 struct flowi4 fl4 = {
1282 .daddr = iph->daddr,
1283 .saddr = iph->saddr,
1284 .flowi4_tos = RT_TOS(iph->tos),
1285 .flowi4_oif = rt->dst.dev->ifindex,
1286 .flowi4_iif = skb->dev->ifindex,
1287 .flowi4_mark = skb->mark,
1288 };
1289
1290 rcu_read_lock();
1291 if (fib_lookup(net: dev_net(dev: rt->dst.dev), flp: &fl4, res: &res, flags: 0) == 0)
1292 src = fib_result_prefsrc(net: dev_net(dev: rt->dst.dev), res: &res);
1293 else
1294 src = inet_select_addr(dev: rt->dst.dev,
1295 dst: rt_nexthop(rt, daddr: iph->daddr),
1296 scope: RT_SCOPE_UNIVERSE);
1297 rcu_read_unlock();
1298 }
1299 memcpy(addr, &src, 4);
1300}
1301
1302#ifdef CONFIG_IP_ROUTE_CLASSID
1303static void set_class_tag(struct rtable *rt, u32 tag)
1304{
1305 if (!(rt->dst.tclassid & 0xFFFF))
1306 rt->dst.tclassid |= tag & 0xFFFF;
1307 if (!(rt->dst.tclassid & 0xFFFF0000))
1308 rt->dst.tclassid |= tag & 0xFFFF0000;
1309}
1310#endif
1311
1312static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1313{
1314 struct net *net = dev_net(dev: dst->dev);
1315 unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1316 unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1317 net->ipv4.ip_rt_min_advmss);
1318
1319 return min(advmss, IPV4_MAX_PMTU - header_size);
1320}
1321
1322INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1323{
1324 return ip_dst_mtu_maybe_forward(dst, forwarding: false);
1325}
1326EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1327
1328static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1329{
1330 struct fnhe_hash_bucket *hash;
1331 struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1332 u32 hval = fnhe_hashfun(daddr);
1333
1334 spin_lock_bh(lock: &fnhe_lock);
1335
1336 hash = rcu_dereference_protected(nhc->nhc_exceptions,
1337 lockdep_is_held(&fnhe_lock));
1338 hash += hval;
1339
1340 fnhe_p = &hash->chain;
1341 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1342 while (fnhe) {
1343 if (fnhe->fnhe_daddr == daddr) {
1344 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1345 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1346 /* set fnhe_daddr to 0 to ensure it won't bind with
1347 * new dsts in rt_bind_exception().
1348 */
1349 fnhe->fnhe_daddr = 0;
1350 fnhe_flush_routes(fnhe);
1351 kfree_rcu(fnhe, rcu);
1352 break;
1353 }
1354 fnhe_p = &fnhe->fnhe_next;
1355 fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1356 lockdep_is_held(&fnhe_lock));
1357 }
1358
1359 spin_unlock_bh(lock: &fnhe_lock);
1360}
1361
1362static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1363 __be32 daddr)
1364{
1365 struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1366 struct fib_nh_exception *fnhe;
1367 u32 hval;
1368
1369 if (!hash)
1370 return NULL;
1371
1372 hval = fnhe_hashfun(daddr);
1373
1374 for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1375 fnhe = rcu_dereference(fnhe->fnhe_next)) {
1376 if (fnhe->fnhe_daddr == daddr) {
1377 if (fnhe->fnhe_expires &&
1378 time_after(jiffies, fnhe->fnhe_expires)) {
1379 ip_del_fnhe(nhc, daddr);
1380 break;
1381 }
1382 return fnhe;
1383 }
1384 }
1385 return NULL;
1386}
1387
1388/* MTU selection:
1389 * 1. mtu on route is locked - use it
1390 * 2. mtu from nexthop exception
1391 * 3. mtu from egress device
1392 */
1393
1394u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1395{
1396 struct fib_nh_common *nhc = res->nhc;
1397 struct net_device *dev = nhc->nhc_dev;
1398 struct fib_info *fi = res->fi;
1399 u32 mtu = 0;
1400
1401 if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) ||
1402 fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1403 mtu = fi->fib_mtu;
1404
1405 if (likely(!mtu)) {
1406 struct fib_nh_exception *fnhe;
1407
1408 fnhe = find_exception(nhc, daddr);
1409 if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1410 mtu = fnhe->fnhe_pmtu;
1411 }
1412
1413 if (likely(!mtu))
1414 mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1415
1416 return mtu - lwtunnel_headroom(lwtstate: nhc->nhc_lwtstate, mtu);
1417}
1418
1419static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1420 __be32 daddr, const bool do_cache)
1421{
1422 bool ret = false;
1423
1424 spin_lock_bh(lock: &fnhe_lock);
1425
1426 if (daddr == fnhe->fnhe_daddr) {
1427 struct rtable __rcu **porig;
1428 struct rtable *orig;
1429 int genid = fnhe_genid(net: dev_net(dev: rt->dst.dev));
1430
1431 if (rt_is_input_route(rt))
1432 porig = &fnhe->fnhe_rth_input;
1433 else
1434 porig = &fnhe->fnhe_rth_output;
1435 orig = rcu_dereference(*porig);
1436
1437 if (fnhe->fnhe_genid != genid) {
1438 fnhe->fnhe_genid = genid;
1439 fnhe->fnhe_gw = 0;
1440 fnhe->fnhe_pmtu = 0;
1441 fnhe->fnhe_expires = 0;
1442 fnhe->fnhe_mtu_locked = false;
1443 fnhe_flush_routes(fnhe);
1444 orig = NULL;
1445 }
1446 fill_route_from_fnhe(rt, fnhe);
1447 if (!rt->rt_gw4) {
1448 rt->rt_gw4 = daddr;
1449 rt->rt_gw_family = AF_INET;
1450 }
1451
1452 if (do_cache) {
1453 dst_hold(dst: &rt->dst);
1454 rcu_assign_pointer(*porig, rt);
1455 if (orig) {
1456 dst_dev_put(dst: &orig->dst);
1457 dst_release(dst: &orig->dst);
1458 }
1459 ret = true;
1460 }
1461
1462 fnhe->fnhe_stamp = jiffies;
1463 }
1464 spin_unlock_bh(lock: &fnhe_lock);
1465
1466 return ret;
1467}
1468
1469static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1470{
1471 struct rtable *orig, *prev, **p;
1472 bool ret = true;
1473
1474 if (rt_is_input_route(rt)) {
1475 p = (struct rtable **)&nhc->nhc_rth_input;
1476 } else {
1477 p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1478 }
1479 orig = *p;
1480
1481 /* hold dst before doing cmpxchg() to avoid race condition
1482 * on this dst
1483 */
1484 dst_hold(dst: &rt->dst);
1485 prev = cmpxchg(p, orig, rt);
1486 if (prev == orig) {
1487 if (orig) {
1488 rt_add_uncached_list(rt: orig);
1489 dst_release(dst: &orig->dst);
1490 }
1491 } else {
1492 dst_release(dst: &rt->dst);
1493 ret = false;
1494 }
1495
1496 return ret;
1497}
1498
1499struct uncached_list {
1500 spinlock_t lock;
1501 struct list_head head;
1502 struct list_head quarantine;
1503};
1504
1505static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1506
1507void rt_add_uncached_list(struct rtable *rt)
1508{
1509 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1510
1511 rt->dst.rt_uncached_list = ul;
1512
1513 spin_lock_bh(lock: &ul->lock);
1514 list_add_tail(new: &rt->dst.rt_uncached, head: &ul->head);
1515 spin_unlock_bh(lock: &ul->lock);
1516}
1517
1518void rt_del_uncached_list(struct rtable *rt)
1519{
1520 if (!list_empty(head: &rt->dst.rt_uncached)) {
1521 struct uncached_list *ul = rt->dst.rt_uncached_list;
1522
1523 spin_lock_bh(lock: &ul->lock);
1524 list_del_init(entry: &rt->dst.rt_uncached);
1525 spin_unlock_bh(lock: &ul->lock);
1526 }
1527}
1528
1529static void ipv4_dst_destroy(struct dst_entry *dst)
1530{
1531 struct rtable *rt = (struct rtable *)dst;
1532
1533 ip_dst_metrics_put(dst);
1534 rt_del_uncached_list(rt);
1535}
1536
1537void rt_flush_dev(struct net_device *dev)
1538{
1539 struct rtable *rt, *safe;
1540 int cpu;
1541
1542 for_each_possible_cpu(cpu) {
1543 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1544
1545 if (list_empty(head: &ul->head))
1546 continue;
1547
1548 spin_lock_bh(lock: &ul->lock);
1549 list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) {
1550 if (rt->dst.dev != dev)
1551 continue;
1552 rt->dst.dev = blackhole_netdev;
1553 netdev_ref_replace(odev: dev, ndev: blackhole_netdev,
1554 tracker: &rt->dst.dev_tracker, GFP_ATOMIC);
1555 list_move(list: &rt->dst.rt_uncached, head: &ul->quarantine);
1556 }
1557 spin_unlock_bh(lock: &ul->lock);
1558 }
1559}
1560
1561static bool rt_cache_valid(const struct rtable *rt)
1562{
1563 return rt &&
1564 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1565 !rt_is_expired(rth: rt);
1566}
1567
1568static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1569 const struct fib_result *res,
1570 struct fib_nh_exception *fnhe,
1571 struct fib_info *fi, u16 type, u32 itag,
1572 const bool do_cache)
1573{
1574 bool cached = false;
1575
1576 if (fi) {
1577 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1578
1579 if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1580 rt->rt_uses_gateway = 1;
1581 rt->rt_gw_family = nhc->nhc_gw_family;
1582 /* only INET and INET6 are supported */
1583 if (likely(nhc->nhc_gw_family == AF_INET))
1584 rt->rt_gw4 = nhc->nhc_gw.ipv4;
1585 else
1586 rt->rt_gw6 = nhc->nhc_gw.ipv6;
1587 }
1588
1589 ip_dst_init_metrics(dst: &rt->dst, fib_metrics: fi->fib_metrics);
1590
1591#ifdef CONFIG_IP_ROUTE_CLASSID
1592 if (nhc->nhc_family == AF_INET) {
1593 struct fib_nh *nh;
1594
1595 nh = container_of(nhc, struct fib_nh, nh_common);
1596 rt->dst.tclassid = nh->nh_tclassid;
1597 }
1598#endif
1599 rt->dst.lwtstate = lwtstate_get(lws: nhc->nhc_lwtstate);
1600 if (unlikely(fnhe))
1601 cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1602 else if (do_cache)
1603 cached = rt_cache_route(nhc, rt);
1604 if (unlikely(!cached)) {
1605 /* Routes we intend to cache in nexthop exception or
1606 * FIB nexthop have the DST_NOCACHE bit clear.
1607 * However, if we are unsuccessful at storing this
1608 * route into the cache we really need to set it.
1609 */
1610 if (!rt->rt_gw4) {
1611 rt->rt_gw_family = AF_INET;
1612 rt->rt_gw4 = daddr;
1613 }
1614 rt_add_uncached_list(rt);
1615 }
1616 } else
1617 rt_add_uncached_list(rt);
1618
1619#ifdef CONFIG_IP_ROUTE_CLASSID
1620#ifdef CONFIG_IP_MULTIPLE_TABLES
1621 set_class_tag(rt, tag: res->tclassid);
1622#endif
1623 set_class_tag(rt, tag: itag);
1624#endif
1625}
1626
1627struct rtable *rt_dst_alloc(struct net_device *dev,
1628 unsigned int flags, u16 type,
1629 bool noxfrm)
1630{
1631 struct rtable *rt;
1632
1633 rt = dst_alloc(ops: &ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1634 flags: (noxfrm ? DST_NOXFRM : 0));
1635
1636 if (rt) {
1637 rt->rt_genid = rt_genid_ipv4(net: dev_net(dev));
1638 rt->rt_flags = flags;
1639 rt->rt_type = type;
1640 rt->rt_is_input = 0;
1641 rt->rt_iif = 0;
1642 rt->rt_pmtu = 0;
1643 rt->rt_mtu_locked = 0;
1644 rt->rt_uses_gateway = 0;
1645 rt->rt_gw_family = 0;
1646 rt->rt_gw4 = 0;
1647
1648 rt->dst.output = ip_output;
1649 if (flags & RTCF_LOCAL)
1650 rt->dst.input = ip_local_deliver;
1651 }
1652
1653 return rt;
1654}
1655EXPORT_SYMBOL(rt_dst_alloc);
1656
1657struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1658{
1659 struct rtable *new_rt;
1660
1661 new_rt = dst_alloc(ops: &ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1662 flags: rt->dst.flags);
1663
1664 if (new_rt) {
1665 new_rt->rt_genid = rt_genid_ipv4(net: dev_net(dev));
1666 new_rt->rt_flags = rt->rt_flags;
1667 new_rt->rt_type = rt->rt_type;
1668 new_rt->rt_is_input = rt->rt_is_input;
1669 new_rt->rt_iif = rt->rt_iif;
1670 new_rt->rt_pmtu = rt->rt_pmtu;
1671 new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1672 new_rt->rt_gw_family = rt->rt_gw_family;
1673 if (rt->rt_gw_family == AF_INET)
1674 new_rt->rt_gw4 = rt->rt_gw4;
1675 else if (rt->rt_gw_family == AF_INET6)
1676 new_rt->rt_gw6 = rt->rt_gw6;
1677
1678 new_rt->dst.input = rt->dst.input;
1679 new_rt->dst.output = rt->dst.output;
1680 new_rt->dst.error = rt->dst.error;
1681 new_rt->dst.lastuse = jiffies;
1682 new_rt->dst.lwtstate = lwtstate_get(lws: rt->dst.lwtstate);
1683 }
1684 return new_rt;
1685}
1686EXPORT_SYMBOL(rt_dst_clone);
1687
1688/* called in rcu_read_lock() section */
1689int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1690 u8 tos, struct net_device *dev,
1691 struct in_device *in_dev, u32 *itag)
1692{
1693 int err;
1694
1695 /* Primary sanity checks. */
1696 if (!in_dev)
1697 return -EINVAL;
1698
1699 if (ipv4_is_multicast(addr: saddr) || ipv4_is_lbcast(addr: saddr) ||
1700 skb->protocol != htons(ETH_P_IP))
1701 return -EINVAL;
1702
1703 if (ipv4_is_loopback(addr: saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1704 return -EINVAL;
1705
1706 if (ipv4_is_zeronet(addr: saddr)) {
1707 if (!ipv4_is_local_multicast(addr: daddr) &&
1708 ip_hdr(skb)->protocol != IPPROTO_IGMP)
1709 return -EINVAL;
1710 } else {
1711 err = fib_validate_source(skb, src: saddr, dst: 0, tos, oif: 0, dev,
1712 idev: in_dev, itag);
1713 if (err < 0)
1714 return err;
1715 }
1716 return 0;
1717}
1718
1719/* called in rcu_read_lock() section */
1720static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1721 u8 tos, struct net_device *dev, int our)
1722{
1723 struct in_device *in_dev = __in_dev_get_rcu(dev);
1724 unsigned int flags = RTCF_MULTICAST;
1725 struct rtable *rth;
1726 u32 itag = 0;
1727 int err;
1728
1729 err = ip_mc_validate_source(skb, daddr, saddr, tos, dev, in_dev, itag: &itag);
1730 if (err)
1731 return err;
1732
1733 if (our)
1734 flags |= RTCF_LOCAL;
1735
1736 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1737 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1738
1739 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1740 false);
1741 if (!rth)
1742 return -ENOBUFS;
1743
1744#ifdef CONFIG_IP_ROUTE_CLASSID
1745 rth->dst.tclassid = itag;
1746#endif
1747 rth->dst.output = ip_rt_bug;
1748 rth->rt_is_input= 1;
1749
1750#ifdef CONFIG_IP_MROUTE
1751 if (!ipv4_is_local_multicast(addr: daddr) && IN_DEV_MFORWARD(in_dev))
1752 rth->dst.input = ip_mr_input;
1753#endif
1754 RT_CACHE_STAT_INC(in_slow_mc);
1755
1756 skb_dst_drop(skb);
1757 skb_dst_set(skb, dst: &rth->dst);
1758 return 0;
1759}
1760
1761
1762static void ip_handle_martian_source(struct net_device *dev,
1763 struct in_device *in_dev,
1764 struct sk_buff *skb,
1765 __be32 daddr,
1766 __be32 saddr)
1767{
1768 RT_CACHE_STAT_INC(in_martian_src);
1769#ifdef CONFIG_IP_ROUTE_VERBOSE
1770 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1771 /*
1772 * RFC1812 recommendation, if source is martian,
1773 * the only hint is MAC header.
1774 */
1775 pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1776 &daddr, &saddr, dev->name);
1777 if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1778 print_hex_dump(KERN_WARNING, prefix_str: "ll header: ",
1779 prefix_type: DUMP_PREFIX_OFFSET, rowsize: 16, groupsize: 1,
1780 buf: skb_mac_header(skb),
1781 len: dev->hard_header_len, ascii: false);
1782 }
1783 }
1784#endif
1785}
1786
1787/* called in rcu_read_lock() section */
1788static int __mkroute_input(struct sk_buff *skb,
1789 const struct fib_result *res,
1790 struct in_device *in_dev,
1791 __be32 daddr, __be32 saddr, u32 tos)
1792{
1793 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1794 struct net_device *dev = nhc->nhc_dev;
1795 struct fib_nh_exception *fnhe;
1796 struct rtable *rth;
1797 int err;
1798 struct in_device *out_dev;
1799 bool do_cache;
1800 u32 itag = 0;
1801
1802 /* get a working reference to the output device */
1803 out_dev = __in_dev_get_rcu(dev);
1804 if (!out_dev) {
1805 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1806 return -EINVAL;
1807 }
1808
1809 err = fib_validate_source(skb, src: saddr, dst: daddr, tos, FIB_RES_OIF(*res),
1810 dev: in_dev->dev, idev: in_dev, itag: &itag);
1811 if (err < 0) {
1812 ip_handle_martian_source(dev: in_dev->dev, in_dev, skb, daddr,
1813 saddr);
1814
1815 goto cleanup;
1816 }
1817
1818 do_cache = res->fi && !itag;
1819 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1820 skb->protocol == htons(ETH_P_IP)) {
1821 __be32 gw;
1822
1823 gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1824 if (IN_DEV_SHARED_MEDIA(out_dev) ||
1825 inet_addr_onlink(in_dev: out_dev, a: saddr, b: gw))
1826 IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1827 }
1828
1829 if (skb->protocol != htons(ETH_P_IP)) {
1830 /* Not IP (i.e. ARP). Do not create route, if it is
1831 * invalid for proxy arp. DNAT routes are always valid.
1832 *
1833 * Proxy arp feature have been extended to allow, ARP
1834 * replies back to the same interface, to support
1835 * Private VLAN switch technologies. See arp.c.
1836 */
1837 if (out_dev == in_dev &&
1838 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1839 err = -EINVAL;
1840 goto cleanup;
1841 }
1842 }
1843
1844 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1845 IPCB(skb)->flags |= IPSKB_NOPOLICY;
1846
1847 fnhe = find_exception(nhc, daddr);
1848 if (do_cache) {
1849 if (fnhe)
1850 rth = rcu_dereference(fnhe->fnhe_rth_input);
1851 else
1852 rth = rcu_dereference(nhc->nhc_rth_input);
1853 if (rt_cache_valid(rt: rth)) {
1854 skb_dst_set_noref(skb, dst: &rth->dst);
1855 goto out;
1856 }
1857 }
1858
1859 rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1860 IN_DEV_ORCONF(out_dev, NOXFRM));
1861 if (!rth) {
1862 err = -ENOBUFS;
1863 goto cleanup;
1864 }
1865
1866 rth->rt_is_input = 1;
1867 RT_CACHE_STAT_INC(in_slow_tot);
1868
1869 rth->dst.input = ip_forward;
1870
1871 rt_set_nexthop(rt: rth, daddr, res, fnhe, fi: res->fi, type: res->type, itag,
1872 do_cache);
1873 lwtunnel_set_redirect(dst: &rth->dst);
1874 skb_dst_set(skb, dst: &rth->dst);
1875out:
1876 err = 0;
1877 cleanup:
1878 return err;
1879}
1880
1881#ifdef CONFIG_IP_ROUTE_MULTIPATH
1882/* To make ICMP packets follow the right flow, the multipath hash is
1883 * calculated from the inner IP addresses.
1884 */
1885static void ip_multipath_l3_keys(const struct sk_buff *skb,
1886 struct flow_keys *hash_keys)
1887{
1888 const struct iphdr *outer_iph = ip_hdr(skb);
1889 const struct iphdr *key_iph = outer_iph;
1890 const struct iphdr *inner_iph;
1891 const struct icmphdr *icmph;
1892 struct iphdr _inner_iph;
1893 struct icmphdr _icmph;
1894
1895 if (likely(outer_iph->protocol != IPPROTO_ICMP))
1896 goto out;
1897
1898 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1899 goto out;
1900
1901 icmph = skb_header_pointer(skb, offset: outer_iph->ihl * 4, len: sizeof(_icmph),
1902 buffer: &_icmph);
1903 if (!icmph)
1904 goto out;
1905
1906 if (!icmp_is_err(type: icmph->type))
1907 goto out;
1908
1909 inner_iph = skb_header_pointer(skb,
1910 offset: outer_iph->ihl * 4 + sizeof(_icmph),
1911 len: sizeof(_inner_iph), buffer: &_inner_iph);
1912 if (!inner_iph)
1913 goto out;
1914
1915 key_iph = inner_iph;
1916out:
1917 hash_keys->addrs.v4addrs.src = key_iph->saddr;
1918 hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1919}
1920
1921static u32 fib_multipath_custom_hash_outer(const struct net *net,
1922 const struct sk_buff *skb,
1923 bool *p_has_inner)
1924{
1925 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1926 struct flow_keys keys, hash_keys;
1927
1928 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1929 return 0;
1930
1931 memset(&hash_keys, 0, sizeof(hash_keys));
1932 skb_flow_dissect_flow_keys(skb, flow: &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1933
1934 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1935 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1936 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1937 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1938 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1939 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1940 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1941 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1942 hash_keys.ports.src = keys.ports.src;
1943 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1944 hash_keys.ports.dst = keys.ports.dst;
1945
1946 *p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1947 return flow_hash_from_keys(keys: &hash_keys);
1948}
1949
1950static u32 fib_multipath_custom_hash_inner(const struct net *net,
1951 const struct sk_buff *skb,
1952 bool has_inner)
1953{
1954 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1955 struct flow_keys keys, hash_keys;
1956
1957 /* We assume the packet carries an encapsulation, but if none was
1958 * encountered during dissection of the outer flow, then there is no
1959 * point in calling the flow dissector again.
1960 */
1961 if (!has_inner)
1962 return 0;
1963
1964 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1965 return 0;
1966
1967 memset(&hash_keys, 0, sizeof(hash_keys));
1968 skb_flow_dissect_flow_keys(skb, flow: &keys, flags: 0);
1969
1970 if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1971 return 0;
1972
1973 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1974 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1975 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1976 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1977 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1978 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1979 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1980 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1981 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1982 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1983 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1984 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
1985 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
1986 hash_keys.tags.flow_label = keys.tags.flow_label;
1987 }
1988
1989 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
1990 hash_keys.basic.ip_proto = keys.basic.ip_proto;
1991 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
1992 hash_keys.ports.src = keys.ports.src;
1993 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
1994 hash_keys.ports.dst = keys.ports.dst;
1995
1996 return flow_hash_from_keys(keys: &hash_keys);
1997}
1998
1999static u32 fib_multipath_custom_hash_skb(const struct net *net,
2000 const struct sk_buff *skb)
2001{
2002 u32 mhash, mhash_inner;
2003 bool has_inner = true;
2004
2005 mhash = fib_multipath_custom_hash_outer(net, skb, p_has_inner: &has_inner);
2006 mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
2007
2008 return jhash_2words(a: mhash, b: mhash_inner, initval: 0);
2009}
2010
2011static u32 fib_multipath_custom_hash_fl4(const struct net *net,
2012 const struct flowi4 *fl4)
2013{
2014 u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
2015 struct flow_keys hash_keys;
2016
2017 if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
2018 return 0;
2019
2020 memset(&hash_keys, 0, sizeof(hash_keys));
2021 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2022 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2023 hash_keys.addrs.v4addrs.src = fl4->saddr;
2024 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2025 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2026 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2027 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2028 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
2029 hash_keys.ports.src = fl4->fl4_sport;
2030 if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2031 hash_keys.ports.dst = fl4->fl4_dport;
2032
2033 return flow_hash_from_keys(keys: &hash_keys);
2034}
2035
2036/* if skb is set it will be used and fl4 can be NULL */
2037int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2038 const struct sk_buff *skb, struct flow_keys *flkeys)
2039{
2040 u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2041 struct flow_keys hash_keys;
2042 u32 mhash = 0;
2043
2044 switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
2045 case 0:
2046 memset(&hash_keys, 0, sizeof(hash_keys));
2047 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2048 if (skb) {
2049 ip_multipath_l3_keys(skb, hash_keys: &hash_keys);
2050 } else {
2051 hash_keys.addrs.v4addrs.src = fl4->saddr;
2052 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2053 }
2054 mhash = flow_hash_from_keys(keys: &hash_keys);
2055 break;
2056 case 1:
2057 /* skb is currently provided only when forwarding */
2058 if (skb) {
2059 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2060 struct flow_keys keys;
2061
2062 /* short-circuit if we already have L4 hash present */
2063 if (skb->l4_hash)
2064 return skb_get_hash_raw(skb) >> 1;
2065
2066 memset(&hash_keys, 0, sizeof(hash_keys));
2067
2068 if (!flkeys) {
2069 skb_flow_dissect_flow_keys(skb, flow: &keys, flags: flag);
2070 flkeys = &keys;
2071 }
2072
2073 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2074 hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2075 hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2076 hash_keys.ports.src = flkeys->ports.src;
2077 hash_keys.ports.dst = flkeys->ports.dst;
2078 hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2079 } else {
2080 memset(&hash_keys, 0, sizeof(hash_keys));
2081 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2082 hash_keys.addrs.v4addrs.src = fl4->saddr;
2083 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2084 hash_keys.ports.src = fl4->fl4_sport;
2085 hash_keys.ports.dst = fl4->fl4_dport;
2086 hash_keys.basic.ip_proto = fl4->flowi4_proto;
2087 }
2088 mhash = flow_hash_from_keys(keys: &hash_keys);
2089 break;
2090 case 2:
2091 memset(&hash_keys, 0, sizeof(hash_keys));
2092 /* skb is currently provided only when forwarding */
2093 if (skb) {
2094 struct flow_keys keys;
2095
2096 skb_flow_dissect_flow_keys(skb, flow: &keys, flags: 0);
2097 /* Inner can be v4 or v6 */
2098 if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2099 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2100 hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2101 hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2102 } else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2103 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2104 hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2105 hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2106 hash_keys.tags.flow_label = keys.tags.flow_label;
2107 hash_keys.basic.ip_proto = keys.basic.ip_proto;
2108 } else {
2109 /* Same as case 0 */
2110 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2111 ip_multipath_l3_keys(skb, hash_keys: &hash_keys);
2112 }
2113 } else {
2114 /* Same as case 0 */
2115 hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2116 hash_keys.addrs.v4addrs.src = fl4->saddr;
2117 hash_keys.addrs.v4addrs.dst = fl4->daddr;
2118 }
2119 mhash = flow_hash_from_keys(keys: &hash_keys);
2120 break;
2121 case 3:
2122 if (skb)
2123 mhash = fib_multipath_custom_hash_skb(net, skb);
2124 else
2125 mhash = fib_multipath_custom_hash_fl4(net, fl4);
2126 break;
2127 }
2128
2129 if (multipath_hash)
2130 mhash = jhash_2words(a: mhash, b: multipath_hash, initval: 0);
2131
2132 return mhash >> 1;
2133}
2134#endif /* CONFIG_IP_ROUTE_MULTIPATH */
2135
2136static int ip_mkroute_input(struct sk_buff *skb,
2137 struct fib_result *res,
2138 struct in_device *in_dev,
2139 __be32 daddr, __be32 saddr, u32 tos,
2140 struct flow_keys *hkeys)
2141{
2142#ifdef CONFIG_IP_ROUTE_MULTIPATH
2143 if (res->fi && fib_info_num_path(fi: res->fi) > 1) {
2144 int h = fib_multipath_hash(net: res->fi->fib_net, NULL, skb, flkeys: hkeys);
2145
2146 fib_select_multipath(res, hash: h);
2147 IPCB(skb)->flags |= IPSKB_MULTIPATH;
2148 }
2149#endif
2150
2151 /* create a routing cache entry */
2152 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
2153}
2154
2155/* Implements all the saddr-related checks as ip_route_input_slow(),
2156 * assuming daddr is valid and the destination is not a local broadcast one.
2157 * Uses the provided hint instead of performing a route lookup.
2158 */
2159int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2160 u8 tos, struct net_device *dev,
2161 const struct sk_buff *hint)
2162{
2163 struct in_device *in_dev = __in_dev_get_rcu(dev);
2164 struct rtable *rt = skb_rtable(skb: hint);
2165 struct net *net = dev_net(dev);
2166 int err = -EINVAL;
2167 u32 tag = 0;
2168
2169 if (ipv4_is_multicast(addr: saddr) || ipv4_is_lbcast(addr: saddr))
2170 goto martian_source;
2171
2172 if (ipv4_is_zeronet(addr: saddr))
2173 goto martian_source;
2174
2175 if (ipv4_is_loopback(addr: saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2176 goto martian_source;
2177
2178 if (rt->rt_type != RTN_LOCAL)
2179 goto skip_validate_source;
2180
2181 tos &= IPTOS_RT_MASK;
2182 err = fib_validate_source(skb, src: saddr, dst: daddr, tos, oif: 0, dev, idev: in_dev, itag: &tag);
2183 if (err < 0)
2184 goto martian_source;
2185
2186skip_validate_source:
2187 skb_dst_copy(nskb: skb, oskb: hint);
2188 return 0;
2189
2190martian_source:
2191 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2192 return err;
2193}
2194
2195/* get device for dst_alloc with local routes */
2196static struct net_device *ip_rt_get_dev(struct net *net,
2197 const struct fib_result *res)
2198{
2199 struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2200 struct net_device *dev = NULL;
2201
2202 if (nhc)
2203 dev = l3mdev_master_dev_rcu(dev: nhc->nhc_dev);
2204
2205 return dev ? : net->loopback_dev;
2206}
2207
2208/*
2209 * NOTE. We drop all the packets that has local source
2210 * addresses, because every properly looped back packet
2211 * must have correct destination already attached by output routine.
2212 * Changes in the enforced policies must be applied also to
2213 * ip_route_use_hint().
2214 *
2215 * Such approach solves two big problems:
2216 * 1. Not simplex devices are handled properly.
2217 * 2. IP spoofing attempts are filtered with 100% of guarantee.
2218 * called with rcu_read_lock()
2219 */
2220
2221static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2222 u8 tos, struct net_device *dev,
2223 struct fib_result *res)
2224{
2225 struct in_device *in_dev = __in_dev_get_rcu(dev);
2226 struct flow_keys *flkeys = NULL, _flkeys;
2227 struct net *net = dev_net(dev);
2228 struct ip_tunnel_info *tun_info;
2229 int err = -EINVAL;
2230 unsigned int flags = 0;
2231 u32 itag = 0;
2232 struct rtable *rth;
2233 struct flowi4 fl4;
2234 bool do_cache = true;
2235
2236 /* IP on this device is disabled. */
2237
2238 if (!in_dev)
2239 goto out;
2240
2241 /* Check for the most weird martians, which can be not detected
2242 * by fib_lookup.
2243 */
2244
2245 tun_info = skb_tunnel_info(skb);
2246 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2247 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2248 else
2249 fl4.flowi4_tun_key.tun_id = 0;
2250 skb_dst_drop(skb);
2251
2252 if (ipv4_is_multicast(addr: saddr) || ipv4_is_lbcast(addr: saddr))
2253 goto martian_source;
2254
2255 res->fi = NULL;
2256 res->table = NULL;
2257 if (ipv4_is_lbcast(addr: daddr) || (saddr == 0 && daddr == 0))
2258 goto brd_input;
2259
2260 /* Accept zero addresses only to limited broadcast;
2261 * I even do not know to fix it or not. Waiting for complains :-)
2262 */
2263 if (ipv4_is_zeronet(addr: saddr))
2264 goto martian_source;
2265
2266 if (ipv4_is_zeronet(addr: daddr))
2267 goto martian_destination;
2268
2269 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2270 * and call it once if daddr or/and saddr are loopback addresses
2271 */
2272 if (ipv4_is_loopback(addr: daddr)) {
2273 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2274 goto martian_destination;
2275 } else if (ipv4_is_loopback(addr: saddr)) {
2276 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net))
2277 goto martian_source;
2278 }
2279
2280 /*
2281 * Now we are ready to route packet.
2282 */
2283 fl4.flowi4_l3mdev = 0;
2284 fl4.flowi4_oif = 0;
2285 fl4.flowi4_iif = dev->ifindex;
2286 fl4.flowi4_mark = skb->mark;
2287 fl4.flowi4_tos = tos;
2288 fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2289 fl4.flowi4_flags = 0;
2290 fl4.daddr = daddr;
2291 fl4.saddr = saddr;
2292 fl4.flowi4_uid = sock_net_uid(net, NULL);
2293 fl4.flowi4_multipath_hash = 0;
2294
2295 if (fib4_rules_early_flow_dissect(net, skb, fl4: &fl4, flkeys: &_flkeys)) {
2296 flkeys = &_flkeys;
2297 } else {
2298 fl4.flowi4_proto = 0;
2299 fl4.fl4_sport = 0;
2300 fl4.fl4_dport = 0;
2301 }
2302
2303 err = fib_lookup(net, flp: &fl4, res, flags: 0);
2304 if (err != 0) {
2305 if (!IN_DEV_FORWARD(in_dev))
2306 err = -EHOSTUNREACH;
2307 goto no_route;
2308 }
2309
2310 if (res->type == RTN_BROADCAST) {
2311 if (IN_DEV_BFORWARD(in_dev))
2312 goto make_route;
2313 /* not do cache if bc_forwarding is enabled */
2314 if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING))
2315 do_cache = false;
2316 goto brd_input;
2317 }
2318
2319 if (res->type == RTN_LOCAL) {
2320 err = fib_validate_source(skb, src: saddr, dst: daddr, tos,
2321 oif: 0, dev, idev: in_dev, itag: &itag);
2322 if (err < 0)
2323 goto martian_source;
2324 goto local_input;
2325 }
2326
2327 if (!IN_DEV_FORWARD(in_dev)) {
2328 err = -EHOSTUNREACH;
2329 goto no_route;
2330 }
2331 if (res->type != RTN_UNICAST)
2332 goto martian_destination;
2333
2334make_route:
2335 err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, hkeys: flkeys);
2336out: return err;
2337
2338brd_input:
2339 if (skb->protocol != htons(ETH_P_IP))
2340 goto e_inval;
2341
2342 if (!ipv4_is_zeronet(addr: saddr)) {
2343 err = fib_validate_source(skb, src: saddr, dst: 0, tos, oif: 0, dev,
2344 idev: in_dev, itag: &itag);
2345 if (err < 0)
2346 goto martian_source;
2347 }
2348 flags |= RTCF_BROADCAST;
2349 res->type = RTN_BROADCAST;
2350 RT_CACHE_STAT_INC(in_brd);
2351
2352local_input:
2353 if (IN_DEV_ORCONF(in_dev, NOPOLICY))
2354 IPCB(skb)->flags |= IPSKB_NOPOLICY;
2355
2356 do_cache &= res->fi && !itag;
2357 if (do_cache) {
2358 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2359
2360 rth = rcu_dereference(nhc->nhc_rth_input);
2361 if (rt_cache_valid(rt: rth)) {
2362 skb_dst_set_noref(skb, dst: &rth->dst);
2363 err = 0;
2364 goto out;
2365 }
2366 }
2367
2368 rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2369 flags | RTCF_LOCAL, res->type, false);
2370 if (!rth)
2371 goto e_nobufs;
2372
2373 rth->dst.output= ip_rt_bug;
2374#ifdef CONFIG_IP_ROUTE_CLASSID
2375 rth->dst.tclassid = itag;
2376#endif
2377 rth->rt_is_input = 1;
2378
2379 RT_CACHE_STAT_INC(in_slow_tot);
2380 if (res->type == RTN_UNREACHABLE) {
2381 rth->dst.input= ip_error;
2382 rth->dst.error= -err;
2383 rth->rt_flags &= ~RTCF_LOCAL;
2384 }
2385
2386 if (do_cache) {
2387 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2388
2389 rth->dst.lwtstate = lwtstate_get(lws: nhc->nhc_lwtstate);
2390 if (lwtunnel_input_redirect(lwtstate: rth->dst.lwtstate)) {
2391 WARN_ON(rth->dst.input == lwtunnel_input);
2392 rth->dst.lwtstate->orig_input = rth->dst.input;
2393 rth->dst.input = lwtunnel_input;
2394 }
2395
2396 if (unlikely(!rt_cache_route(nhc, rth)))
2397 rt_add_uncached_list(rt: rth);
2398 }
2399 skb_dst_set(skb, dst: &rth->dst);
2400 err = 0;
2401 goto out;
2402
2403no_route:
2404 RT_CACHE_STAT_INC(in_no_route);
2405 res->type = RTN_UNREACHABLE;
2406 res->fi = NULL;
2407 res->table = NULL;
2408 goto local_input;
2409
2410 /*
2411 * Do not cache martian addresses: they should be logged (RFC1812)
2412 */
2413martian_destination:
2414 RT_CACHE_STAT_INC(in_martian_dst);
2415#ifdef CONFIG_IP_ROUTE_VERBOSE
2416 if (IN_DEV_LOG_MARTIANS(in_dev))
2417 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2418 &daddr, &saddr, dev->name);
2419#endif
2420
2421e_inval:
2422 err = -EINVAL;
2423 goto out;
2424
2425e_nobufs:
2426 err = -ENOBUFS;
2427 goto out;
2428
2429martian_source:
2430 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2431 goto out;
2432}
2433
2434/* called with rcu_read_lock held */
2435static int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2436 u8 tos, struct net_device *dev, struct fib_result *res)
2437{
2438 /* Multicast recognition logic is moved from route cache to here.
2439 * The problem was that too many Ethernet cards have broken/missing
2440 * hardware multicast filters :-( As result the host on multicasting
2441 * network acquires a lot of useless route cache entries, sort of
2442 * SDR messages from all the world. Now we try to get rid of them.
2443 * Really, provided software IP multicast filter is organized
2444 * reasonably (at least, hashed), it does not result in a slowdown
2445 * comparing with route cache reject entries.
2446 * Note, that multicast routers are not affected, because
2447 * route cache entry is created eventually.
2448 */
2449 if (ipv4_is_multicast(addr: daddr)) {
2450 struct in_device *in_dev = __in_dev_get_rcu(dev);
2451 int our = 0;
2452 int err = -EINVAL;
2453
2454 if (!in_dev)
2455 return err;
2456 our = ip_check_mc_rcu(dev: in_dev, mc_addr: daddr, src_addr: saddr,
2457 proto: ip_hdr(skb)->protocol);
2458
2459 /* check l3 master if no match yet */
2460 if (!our && netif_is_l3_slave(dev)) {
2461 struct in_device *l3_in_dev;
2462
2463 l3_in_dev = __in_dev_get_rcu(dev: skb->dev);
2464 if (l3_in_dev)
2465 our = ip_check_mc_rcu(dev: l3_in_dev, mc_addr: daddr, src_addr: saddr,
2466 proto: ip_hdr(skb)->protocol);
2467 }
2468
2469 if (our
2470#ifdef CONFIG_IP_MROUTE
2471 ||
2472 (!ipv4_is_local_multicast(addr: daddr) &&
2473 IN_DEV_MFORWARD(in_dev))
2474#endif
2475 ) {
2476 err = ip_route_input_mc(skb, daddr, saddr,
2477 tos, dev, our);
2478 }
2479 return err;
2480 }
2481
2482 return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);
2483}
2484
2485int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2486 u8 tos, struct net_device *dev)
2487{
2488 struct fib_result res;
2489 int err;
2490
2491 tos &= IPTOS_RT_MASK;
2492 rcu_read_lock();
2493 err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, res: &res);
2494 rcu_read_unlock();
2495
2496 return err;
2497}
2498EXPORT_SYMBOL(ip_route_input_noref);
2499
2500/* called with rcu_read_lock() */
2501static struct rtable *__mkroute_output(const struct fib_result *res,
2502 const struct flowi4 *fl4, int orig_oif,
2503 struct net_device *dev_out,
2504 unsigned int flags)
2505{
2506 struct fib_info *fi = res->fi;
2507 struct fib_nh_exception *fnhe;
2508 struct in_device *in_dev;
2509 u16 type = res->type;
2510 struct rtable *rth;
2511 bool do_cache;
2512
2513 in_dev = __in_dev_get_rcu(dev: dev_out);
2514 if (!in_dev)
2515 return ERR_PTR(error: -EINVAL);
2516
2517 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2518 if (ipv4_is_loopback(addr: fl4->saddr) &&
2519 !(dev_out->flags & IFF_LOOPBACK) &&
2520 !netif_is_l3_master(dev: dev_out))
2521 return ERR_PTR(error: -EINVAL);
2522
2523 if (ipv4_is_lbcast(addr: fl4->daddr))
2524 type = RTN_BROADCAST;
2525 else if (ipv4_is_multicast(addr: fl4->daddr))
2526 type = RTN_MULTICAST;
2527 else if (ipv4_is_zeronet(addr: fl4->daddr))
2528 return ERR_PTR(error: -EINVAL);
2529
2530 if (dev_out->flags & IFF_LOOPBACK)
2531 flags |= RTCF_LOCAL;
2532
2533 do_cache = true;
2534 if (type == RTN_BROADCAST) {
2535 flags |= RTCF_BROADCAST | RTCF_LOCAL;
2536 fi = NULL;
2537 } else if (type == RTN_MULTICAST) {
2538 flags |= RTCF_MULTICAST | RTCF_LOCAL;
2539 if (!ip_check_mc_rcu(dev: in_dev, mc_addr: fl4->daddr, src_addr: fl4->saddr,
2540 proto: fl4->flowi4_proto))
2541 flags &= ~RTCF_LOCAL;
2542 else
2543 do_cache = false;
2544 /* If multicast route do not exist use
2545 * default one, but do not gateway in this case.
2546 * Yes, it is hack.
2547 */
2548 if (fi && res->prefixlen < 4)
2549 fi = NULL;
2550 } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2551 (orig_oif != dev_out->ifindex)) {
2552 /* For local routes that require a particular output interface
2553 * we do not want to cache the result. Caching the result
2554 * causes incorrect behaviour when there are multiple source
2555 * addresses on the interface, the end result being that if the
2556 * intended recipient is waiting on that interface for the
2557 * packet he won't receive it because it will be delivered on
2558 * the loopback interface and the IP_PKTINFO ipi_ifindex will
2559 * be set to the loopback interface as well.
2560 */
2561 do_cache = false;
2562 }
2563
2564 fnhe = NULL;
2565 do_cache &= fi != NULL;
2566 if (fi) {
2567 struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2568 struct rtable __rcu **prth;
2569
2570 fnhe = find_exception(nhc, daddr: fl4->daddr);
2571 if (!do_cache)
2572 goto add;
2573 if (fnhe) {
2574 prth = &fnhe->fnhe_rth_output;
2575 } else {
2576 if (unlikely(fl4->flowi4_flags &
2577 FLOWI_FLAG_KNOWN_NH &&
2578 !(nhc->nhc_gw_family &&
2579 nhc->nhc_scope == RT_SCOPE_LINK))) {
2580 do_cache = false;
2581 goto add;
2582 }
2583 prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2584 }
2585 rth = rcu_dereference(*prth);
2586 if (rt_cache_valid(rt: rth) && dst_hold_safe(dst: &rth->dst))
2587 return rth;
2588 }
2589
2590add:
2591 rth = rt_dst_alloc(dev_out, flags, type,
2592 IN_DEV_ORCONF(in_dev, NOXFRM));
2593 if (!rth)
2594 return ERR_PTR(error: -ENOBUFS);
2595
2596 rth->rt_iif = orig_oif;
2597
2598 RT_CACHE_STAT_INC(out_slow_tot);
2599
2600 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2601 if (flags & RTCF_LOCAL &&
2602 !(dev_out->flags & IFF_LOOPBACK)) {
2603 rth->dst.output = ip_mc_output;
2604 RT_CACHE_STAT_INC(out_slow_mc);
2605 }
2606#ifdef CONFIG_IP_MROUTE
2607 if (type == RTN_MULTICAST) {
2608 if (IN_DEV_MFORWARD(in_dev) &&
2609 !ipv4_is_local_multicast(addr: fl4->daddr)) {
2610 rth->dst.input = ip_mr_input;
2611 rth->dst.output = ip_mc_output;
2612 }
2613 }
2614#endif
2615 }
2616
2617 rt_set_nexthop(rt: rth, daddr: fl4->daddr, res, fnhe, fi, type, itag: 0, do_cache);
2618 lwtunnel_set_redirect(dst: &rth->dst);
2619
2620 return rth;
2621}
2622
2623/*
2624 * Major route resolver routine.
2625 */
2626
2627struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2628 const struct sk_buff *skb)
2629{
2630 struct fib_result res = {
2631 .type = RTN_UNSPEC,
2632 .fi = NULL,
2633 .table = NULL,
2634 .tclassid = 0,
2635 };
2636 struct rtable *rth;
2637
2638 fl4->flowi4_iif = LOOPBACK_IFINDEX;
2639 ip_rt_fix_tos(fl4);
2640
2641 rcu_read_lock();
2642 rth = ip_route_output_key_hash_rcu(net, flp: fl4, res: &res, skb);
2643 rcu_read_unlock();
2644
2645 return rth;
2646}
2647EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2648
2649struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2650 struct fib_result *res,
2651 const struct sk_buff *skb)
2652{
2653 struct net_device *dev_out = NULL;
2654 int orig_oif = fl4->flowi4_oif;
2655 unsigned int flags = 0;
2656 struct rtable *rth;
2657 int err;
2658
2659 if (fl4->saddr) {
2660 if (ipv4_is_multicast(addr: fl4->saddr) ||
2661 ipv4_is_lbcast(addr: fl4->saddr) ||
2662 ipv4_is_zeronet(addr: fl4->saddr)) {
2663 rth = ERR_PTR(error: -EINVAL);
2664 goto out;
2665 }
2666
2667 rth = ERR_PTR(error: -ENETUNREACH);
2668
2669 /* I removed check for oif == dev_out->oif here.
2670 * It was wrong for two reasons:
2671 * 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2672 * is assigned to multiple interfaces.
2673 * 2. Moreover, we are allowed to send packets with saddr
2674 * of another iface. --ANK
2675 */
2676
2677 if (fl4->flowi4_oif == 0 &&
2678 (ipv4_is_multicast(addr: fl4->daddr) ||
2679 ipv4_is_lbcast(addr: fl4->daddr))) {
2680 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2681 dev_out = __ip_dev_find(net, addr: fl4->saddr, devref: false);
2682 if (!dev_out)
2683 goto out;
2684
2685 /* Special hack: user can direct multicasts
2686 * and limited broadcast via necessary interface
2687 * without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2688 * This hack is not just for fun, it allows
2689 * vic,vat and friends to work.
2690 * They bind socket to loopback, set ttl to zero
2691 * and expect that it will work.
2692 * From the viewpoint of routing cache they are broken,
2693 * because we are not allowed to build multicast path
2694 * with loopback source addr (look, routing cache
2695 * cannot know, that ttl is zero, so that packet
2696 * will not leave this host and route is valid).
2697 * Luckily, this hack is good workaround.
2698 */
2699
2700 fl4->flowi4_oif = dev_out->ifindex;
2701 goto make_route;
2702 }
2703
2704 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2705 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2706 if (!__ip_dev_find(net, addr: fl4->saddr, devref: false))
2707 goto out;
2708 }
2709 }
2710
2711
2712 if (fl4->flowi4_oif) {
2713 dev_out = dev_get_by_index_rcu(net, ifindex: fl4->flowi4_oif);
2714 rth = ERR_PTR(error: -ENODEV);
2715 if (!dev_out)
2716 goto out;
2717
2718 /* RACE: Check return value of inet_select_addr instead. */
2719 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev: dev_out)) {
2720 rth = ERR_PTR(error: -ENETUNREACH);
2721 goto out;
2722 }
2723 if (ipv4_is_local_multicast(addr: fl4->daddr) ||
2724 ipv4_is_lbcast(addr: fl4->daddr) ||
2725 fl4->flowi4_proto == IPPROTO_IGMP) {
2726 if (!fl4->saddr)
2727 fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2728 scope: RT_SCOPE_LINK);
2729 goto make_route;
2730 }
2731 if (!fl4->saddr) {
2732 if (ipv4_is_multicast(addr: fl4->daddr))
2733 fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2734 scope: fl4->flowi4_scope);
2735 else if (!fl4->daddr)
2736 fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2737 scope: RT_SCOPE_HOST);
2738 }
2739 }
2740
2741 if (!fl4->daddr) {
2742 fl4->daddr = fl4->saddr;
2743 if (!fl4->daddr)
2744 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2745 dev_out = net->loopback_dev;
2746 fl4->flowi4_oif = LOOPBACK_IFINDEX;
2747 res->type = RTN_LOCAL;
2748 flags |= RTCF_LOCAL;
2749 goto make_route;
2750 }
2751
2752 err = fib_lookup(net, flp: fl4, res, flags: 0);
2753 if (err) {
2754 res->fi = NULL;
2755 res->table = NULL;
2756 if (fl4->flowi4_oif &&
2757 (ipv4_is_multicast(addr: fl4->daddr) || !fl4->flowi4_l3mdev)) {
2758 /* Apparently, routing tables are wrong. Assume,
2759 * that the destination is on link.
2760 *
2761 * WHY? DW.
2762 * Because we are allowed to send to iface
2763 * even if it has NO routes and NO assigned
2764 * addresses. When oif is specified, routing
2765 * tables are looked up with only one purpose:
2766 * to catch if destination is gatewayed, rather than
2767 * direct. Moreover, if MSG_DONTROUTE is set,
2768 * we send packet, ignoring both routing tables
2769 * and ifaddr state. --ANK
2770 *
2771 *
2772 * We could make it even if oif is unknown,
2773 * likely IPv6, but we do not.
2774 */
2775
2776 if (fl4->saddr == 0)
2777 fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2778 scope: RT_SCOPE_LINK);
2779 res->type = RTN_UNICAST;
2780 goto make_route;
2781 }
2782 rth = ERR_PTR(error: err);
2783 goto out;
2784 }
2785
2786 if (res->type == RTN_LOCAL) {
2787 if (!fl4->saddr) {
2788 if (res->fi->fib_prefsrc)
2789 fl4->saddr = res->fi->fib_prefsrc;
2790 else
2791 fl4->saddr = fl4->daddr;
2792 }
2793
2794 /* L3 master device is the loopback for that domain */
2795 dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2796 net->loopback_dev;
2797
2798 /* make sure orig_oif points to fib result device even
2799 * though packet rx/tx happens over loopback or l3mdev
2800 */
2801 orig_oif = FIB_RES_OIF(*res);
2802
2803 fl4->flowi4_oif = dev_out->ifindex;
2804 flags |= RTCF_LOCAL;
2805 goto make_route;
2806 }
2807
2808 fib_select_path(net, res, fl4, skb);
2809
2810 dev_out = FIB_RES_DEV(*res);
2811
2812make_route:
2813 rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2814
2815out:
2816 return rth;
2817}
2818
2819static struct dst_ops ipv4_dst_blackhole_ops = {
2820 .family = AF_INET,
2821 .default_advmss = ipv4_default_advmss,
2822 .neigh_lookup = ipv4_neigh_lookup,
2823 .check = dst_blackhole_check,
2824 .cow_metrics = dst_blackhole_cow_metrics,
2825 .update_pmtu = dst_blackhole_update_pmtu,
2826 .redirect = dst_blackhole_redirect,
2827 .mtu = dst_blackhole_mtu,
2828};
2829
2830struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2831{
2832 struct rtable *ort = (struct rtable *) dst_orig;
2833 struct rtable *rt;
2834
2835 rt = dst_alloc(ops: &ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, flags: 0);
2836 if (rt) {
2837 struct dst_entry *new = &rt->dst;
2838
2839 new->__use = 1;
2840 new->input = dst_discard;
2841 new->output = dst_discard_out;
2842
2843 new->dev = net->loopback_dev;
2844 netdev_hold(dev: new->dev, tracker: &new->dev_tracker, GFP_ATOMIC);
2845
2846 rt->rt_is_input = ort->rt_is_input;
2847 rt->rt_iif = ort->rt_iif;
2848 rt->rt_pmtu = ort->rt_pmtu;
2849 rt->rt_mtu_locked = ort->rt_mtu_locked;
2850
2851 rt->rt_genid = rt_genid_ipv4(net);
2852 rt->rt_flags = ort->rt_flags;
2853 rt->rt_type = ort->rt_type;
2854 rt->rt_uses_gateway = ort->rt_uses_gateway;
2855 rt->rt_gw_family = ort->rt_gw_family;
2856 if (rt->rt_gw_family == AF_INET)
2857 rt->rt_gw4 = ort->rt_gw4;
2858 else if (rt->rt_gw_family == AF_INET6)
2859 rt->rt_gw6 = ort->rt_gw6;
2860 }
2861
2862 dst_release(dst: dst_orig);
2863
2864 return rt ? &rt->dst : ERR_PTR(error: -ENOMEM);
2865}
2866
2867struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2868 const struct sock *sk)
2869{
2870 struct rtable *rt = __ip_route_output_key(net, flp: flp4);
2871
2872 if (IS_ERR(ptr: rt))
2873 return rt;
2874
2875 if (flp4->flowi4_proto) {
2876 flp4->flowi4_oif = rt->dst.dev->ifindex;
2877 rt = (struct rtable *)xfrm_lookup_route(net, dst_orig: &rt->dst,
2878 fl: flowi4_to_flowi(fl4: flp4),
2879 sk, flags: 0);
2880 }
2881
2882 return rt;
2883}
2884EXPORT_SYMBOL_GPL(ip_route_output_flow);
2885
2886/* called with rcu_read_lock held */
2887static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2888 struct rtable *rt, u32 table_id, struct flowi4 *fl4,
2889 struct sk_buff *skb, u32 portid, u32 seq,
2890 unsigned int flags)
2891{
2892 struct rtmsg *r;
2893 struct nlmsghdr *nlh;
2894 unsigned long expires = 0;
2895 u32 error;
2896 u32 metrics[RTAX_MAX];
2897
2898 nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, payload: sizeof(*r), flags);
2899 if (!nlh)
2900 return -EMSGSIZE;
2901
2902 r = nlmsg_data(nlh);
2903 r->rtm_family = AF_INET;
2904 r->rtm_dst_len = 32;
2905 r->rtm_src_len = 0;
2906 r->rtm_tos = fl4 ? fl4->flowi4_tos : 0;
2907 r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2908 if (nla_put_u32(skb, attrtype: RTA_TABLE, value: table_id))
2909 goto nla_put_failure;
2910 r->rtm_type = rt->rt_type;
2911 r->rtm_scope = RT_SCOPE_UNIVERSE;
2912 r->rtm_protocol = RTPROT_UNSPEC;
2913 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2914 if (rt->rt_flags & RTCF_NOTIFY)
2915 r->rtm_flags |= RTM_F_NOTIFY;
2916 if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2917 r->rtm_flags |= RTCF_DOREDIRECT;
2918
2919 if (nla_put_in_addr(skb, attrtype: RTA_DST, addr: dst))
2920 goto nla_put_failure;
2921 if (src) {
2922 r->rtm_src_len = 32;
2923 if (nla_put_in_addr(skb, attrtype: RTA_SRC, addr: src))
2924 goto nla_put_failure;
2925 }
2926 if (rt->dst.dev &&
2927 nla_put_u32(skb, attrtype: RTA_OIF, value: rt->dst.dev->ifindex))
2928 goto nla_put_failure;
2929 if (rt->dst.lwtstate &&
2930 lwtunnel_fill_encap(skb, lwtstate: rt->dst.lwtstate, encap_attr: RTA_ENCAP, encap_type_attr: RTA_ENCAP_TYPE) < 0)
2931 goto nla_put_failure;
2932#ifdef CONFIG_IP_ROUTE_CLASSID
2933 if (rt->dst.tclassid &&
2934 nla_put_u32(skb, attrtype: RTA_FLOW, value: rt->dst.tclassid))
2935 goto nla_put_failure;
2936#endif
2937 if (fl4 && !rt_is_input_route(rt) &&
2938 fl4->saddr != src) {
2939 if (nla_put_in_addr(skb, attrtype: RTA_PREFSRC, addr: fl4->saddr))
2940 goto nla_put_failure;
2941 }
2942 if (rt->rt_uses_gateway) {
2943 if (rt->rt_gw_family == AF_INET &&
2944 nla_put_in_addr(skb, attrtype: RTA_GATEWAY, addr: rt->rt_gw4)) {
2945 goto nla_put_failure;
2946 } else if (rt->rt_gw_family == AF_INET6) {
2947 int alen = sizeof(struct in6_addr);
2948 struct nlattr *nla;
2949 struct rtvia *via;
2950
2951 nla = nla_reserve(skb, attrtype: RTA_VIA, attrlen: alen + 2);
2952 if (!nla)
2953 goto nla_put_failure;
2954
2955 via = nla_data(nla);
2956 via->rtvia_family = AF_INET6;
2957 memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
2958 }
2959 }
2960
2961 expires = rt->dst.expires;
2962 if (expires) {
2963 unsigned long now = jiffies;
2964
2965 if (time_before(now, expires))
2966 expires -= now;
2967 else
2968 expires = 0;
2969 }
2970
2971 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
2972 if (rt->rt_pmtu && expires)
2973 metrics[RTAX_MTU - 1] = rt->rt_pmtu;
2974 if (rt->rt_mtu_locked && expires)
2975 metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
2976 if (rtnetlink_put_metrics(skb, metrics) < 0)
2977 goto nla_put_failure;
2978
2979 if (fl4) {
2980 if (fl4->flowi4_mark &&
2981 nla_put_u32(skb, attrtype: RTA_MARK, value: fl4->flowi4_mark))
2982 goto nla_put_failure;
2983
2984 if (!uid_eq(left: fl4->flowi4_uid, INVALID_UID) &&
2985 nla_put_u32(skb, attrtype: RTA_UID,
2986 value: from_kuid_munged(current_user_ns(),
2987 uid: fl4->flowi4_uid)))
2988 goto nla_put_failure;
2989
2990 if (rt_is_input_route(rt)) {
2991#ifdef CONFIG_IP_MROUTE
2992 if (ipv4_is_multicast(addr: dst) &&
2993 !ipv4_is_local_multicast(addr: dst) &&
2994 IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) {
2995 int err = ipmr_get_route(net, skb,
2996 saddr: fl4->saddr, daddr: fl4->daddr,
2997 rtm: r, portid);
2998
2999 if (err <= 0) {
3000 if (err == 0)
3001 return 0;
3002 goto nla_put_failure;
3003 }
3004 } else
3005#endif
3006 if (nla_put_u32(skb, attrtype: RTA_IIF, value: fl4->flowi4_iif))
3007 goto nla_put_failure;
3008 }
3009 }
3010
3011 error = rt->dst.error;
3012
3013 if (rtnl_put_cacheinfo(skb, dst: &rt->dst, id: 0, expires, error) < 0)
3014 goto nla_put_failure;
3015
3016 nlmsg_end(skb, nlh);
3017 return 0;
3018
3019nla_put_failure:
3020 nlmsg_cancel(skb, nlh);
3021 return -EMSGSIZE;
3022}
3023
3024static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3025 struct netlink_callback *cb, u32 table_id,
3026 struct fnhe_hash_bucket *bucket, int genid,
3027 int *fa_index, int fa_start, unsigned int flags)
3028{
3029 int i;
3030
3031 for (i = 0; i < FNHE_HASH_SIZE; i++) {
3032 struct fib_nh_exception *fnhe;
3033
3034 for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3035 fnhe = rcu_dereference(fnhe->fnhe_next)) {
3036 struct rtable *rt;
3037 int err;
3038
3039 if (*fa_index < fa_start)
3040 goto next;
3041
3042 if (fnhe->fnhe_genid != genid)
3043 goto next;
3044
3045 if (fnhe->fnhe_expires &&
3046 time_after(jiffies, fnhe->fnhe_expires))
3047 goto next;
3048
3049 rt = rcu_dereference(fnhe->fnhe_rth_input);
3050 if (!rt)
3051 rt = rcu_dereference(fnhe->fnhe_rth_output);
3052 if (!rt)
3053 goto next;
3054
3055 err = rt_fill_info(net, dst: fnhe->fnhe_daddr, src: 0, rt,
3056 table_id, NULL, skb,
3057 NETLINK_CB(cb->skb).portid,
3058 seq: cb->nlh->nlmsg_seq, flags);
3059 if (err)
3060 return err;
3061next:
3062 (*fa_index)++;
3063 }
3064 }
3065
3066 return 0;
3067}
3068
3069int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3070 u32 table_id, struct fib_info *fi,
3071 int *fa_index, int fa_start, unsigned int flags)
3072{
3073 struct net *net = sock_net(sk: cb->skb->sk);
3074 int nhsel, genid = fnhe_genid(net);
3075
3076 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3077 struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3078 struct fnhe_hash_bucket *bucket;
3079 int err;
3080
3081 if (nhc->nhc_flags & RTNH_F_DEAD)
3082 continue;
3083
3084 rcu_read_lock();
3085 bucket = rcu_dereference(nhc->nhc_exceptions);
3086 err = 0;
3087 if (bucket)
3088 err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3089 genid, fa_index, fa_start,
3090 flags);
3091 rcu_read_unlock();
3092 if (err)
3093 return err;
3094 }
3095
3096 return 0;
3097}
3098
3099static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3100 u8 ip_proto, __be16 sport,
3101 __be16 dport)
3102{
3103 struct sk_buff *skb;
3104 struct iphdr *iph;
3105
3106 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3107 if (!skb)
3108 return NULL;
3109
3110 /* Reserve room for dummy headers, this skb can pass
3111 * through good chunk of routing engine.
3112 */
3113 skb_reset_mac_header(skb);
3114 skb_reset_network_header(skb);
3115 skb->protocol = htons(ETH_P_IP);
3116 iph = skb_put(skb, len: sizeof(struct iphdr));
3117 iph->protocol = ip_proto;
3118 iph->saddr = src;
3119 iph->daddr = dst;
3120 iph->version = 0x4;
3121 iph->frag_off = 0;
3122 iph->ihl = 0x5;
3123 skb_set_transport_header(skb, offset: skb->len);
3124
3125 switch (iph->protocol) {
3126 case IPPROTO_UDP: {
3127 struct udphdr *udph;
3128
3129 udph = skb_put_zero(skb, len: sizeof(struct udphdr));
3130 udph->source = sport;
3131 udph->dest = dport;
3132 udph->len = htons(sizeof(struct udphdr));
3133 udph->check = 0;
3134 break;
3135 }
3136 case IPPROTO_TCP: {
3137 struct tcphdr *tcph;
3138
3139 tcph = skb_put_zero(skb, len: sizeof(struct tcphdr));
3140 tcph->source = sport;
3141 tcph->dest = dport;
3142 tcph->doff = sizeof(struct tcphdr) / 4;
3143 tcph->rst = 1;
3144 tcph->check = ~tcp_v4_check(len: sizeof(struct tcphdr),
3145 saddr: src, daddr: dst, base: 0);
3146 break;
3147 }
3148 case IPPROTO_ICMP: {
3149 struct icmphdr *icmph;
3150
3151 icmph = skb_put_zero(skb, len: sizeof(struct icmphdr));
3152 icmph->type = ICMP_ECHO;
3153 icmph->code = 0;
3154 }
3155 }
3156
3157 return skb;
3158}
3159
3160static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3161 const struct nlmsghdr *nlh,
3162 struct nlattr **tb,
3163 struct netlink_ext_ack *extack)
3164{
3165 struct rtmsg *rtm;
3166 int i, err;
3167
3168 if (nlh->nlmsg_len < nlmsg_msg_size(payload: sizeof(*rtm))) {
3169 NL_SET_ERR_MSG(extack,
3170 "ipv4: Invalid header for route get request");
3171 return -EINVAL;
3172 }
3173
3174 if (!netlink_strict_get_check(skb))
3175 return nlmsg_parse_deprecated(nlh, hdrlen: sizeof(*rtm), tb, RTA_MAX,
3176 policy: rtm_ipv4_policy, extack);
3177
3178 rtm = nlmsg_data(nlh);
3179 if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3180 (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3181 rtm->rtm_table || rtm->rtm_protocol ||
3182 rtm->rtm_scope || rtm->rtm_type) {
3183 NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3184 return -EINVAL;
3185 }
3186
3187 if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3188 RTM_F_LOOKUP_TABLE |
3189 RTM_F_FIB_MATCH)) {
3190 NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3191 return -EINVAL;
3192 }
3193
3194 err = nlmsg_parse_deprecated_strict(nlh, hdrlen: sizeof(*rtm), tb, RTA_MAX,
3195 policy: rtm_ipv4_policy, extack);
3196 if (err)
3197 return err;
3198
3199 if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3200 (tb[RTA_DST] && !rtm->rtm_dst_len)) {
3201 NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3202 return -EINVAL;
3203 }
3204
3205 for (i = 0; i <= RTA_MAX; i++) {
3206 if (!tb[i])
3207 continue;
3208
3209 switch (i) {
3210 case RTA_IIF:
3211 case RTA_OIF:
3212 case RTA_SRC:
3213 case RTA_DST:
3214 case RTA_IP_PROTO:
3215 case RTA_SPORT:
3216 case RTA_DPORT:
3217 case RTA_MARK:
3218 case RTA_UID:
3219 break;
3220 default:
3221 NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3222 return -EINVAL;
3223 }
3224 }
3225
3226 return 0;
3227}
3228
3229static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3230 struct netlink_ext_ack *extack)
3231{
3232 struct net *net = sock_net(sk: in_skb->sk);
3233 struct nlattr *tb[RTA_MAX+1];
3234 u32 table_id = RT_TABLE_MAIN;
3235 __be16 sport = 0, dport = 0;
3236 struct fib_result res = {};
3237 u8 ip_proto = IPPROTO_UDP;
3238 struct rtable *rt = NULL;
3239 struct sk_buff *skb;
3240 struct rtmsg *rtm;
3241 struct flowi4 fl4 = {};
3242 __be32 dst = 0;
3243 __be32 src = 0;
3244 kuid_t uid;
3245 u32 iif;
3246 int err;
3247 int mark;
3248
3249 err = inet_rtm_valid_getroute_req(skb: in_skb, nlh, tb, extack);
3250 if (err < 0)
3251 return err;
3252
3253 rtm = nlmsg_data(nlh);
3254 src = tb[RTA_SRC] ? nla_get_in_addr(nla: tb[RTA_SRC]) : 0;
3255 dst = tb[RTA_DST] ? nla_get_in_addr(nla: tb[RTA_DST]) : 0;
3256 iif = tb[RTA_IIF] ? nla_get_u32(nla: tb[RTA_IIF]) : 0;
3257 mark = tb[RTA_MARK] ? nla_get_u32(nla: tb[RTA_MARK]) : 0;
3258 if (tb[RTA_UID])
3259 uid = make_kuid(current_user_ns(), uid: nla_get_u32(nla: tb[RTA_UID]));
3260 else
3261 uid = (iif ? INVALID_UID : current_uid());
3262
3263 if (tb[RTA_IP_PROTO]) {
3264 err = rtm_getroute_parse_ip_proto(attr: tb[RTA_IP_PROTO],
3265 ip_proto: &ip_proto, AF_INET, extack);
3266 if (err)
3267 return err;
3268 }
3269
3270 if (tb[RTA_SPORT])
3271 sport = nla_get_be16(nla: tb[RTA_SPORT]);
3272
3273 if (tb[RTA_DPORT])
3274 dport = nla_get_be16(nla: tb[RTA_DPORT]);
3275
3276 skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3277 if (!skb)
3278 return -ENOBUFS;
3279
3280 fl4.daddr = dst;
3281 fl4.saddr = src;
3282 fl4.flowi4_tos = rtm->rtm_tos & IPTOS_RT_MASK;
3283 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(nla: tb[RTA_OIF]) : 0;
3284 fl4.flowi4_mark = mark;
3285 fl4.flowi4_uid = uid;
3286 if (sport)
3287 fl4.fl4_sport = sport;
3288 if (dport)
3289 fl4.fl4_dport = dport;
3290 fl4.flowi4_proto = ip_proto;
3291
3292 rcu_read_lock();
3293
3294 if (iif) {
3295 struct net_device *dev;
3296
3297 dev = dev_get_by_index_rcu(net, ifindex: iif);
3298 if (!dev) {
3299 err = -ENODEV;
3300 goto errout_rcu;
3301 }
3302
3303 fl4.flowi4_iif = iif; /* for rt_fill_info */
3304 skb->dev = dev;
3305 skb->mark = mark;
3306 err = ip_route_input_rcu(skb, daddr: dst, saddr: src,
3307 tos: rtm->rtm_tos & IPTOS_RT_MASK, dev,
3308 res: &res);
3309
3310 rt = skb_rtable(skb);
3311 if (err == 0 && rt->dst.error)
3312 err = -rt->dst.error;
3313 } else {
3314 fl4.flowi4_iif = LOOPBACK_IFINDEX;
3315 skb->dev = net->loopback_dev;
3316 rt = ip_route_output_key_hash_rcu(net, fl4: &fl4, res: &res, skb);
3317 err = 0;
3318 if (IS_ERR(ptr: rt))
3319 err = PTR_ERR(ptr: rt);
3320 else
3321 skb_dst_set(skb, dst: &rt->dst);
3322 }
3323
3324 if (err)
3325 goto errout_rcu;
3326
3327 if (rtm->rtm_flags & RTM_F_NOTIFY)
3328 rt->rt_flags |= RTCF_NOTIFY;
3329
3330 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3331 table_id = res.table ? res.table->tb_id : 0;
3332
3333 /* reset skb for netlink reply msg */
3334 skb_trim(skb, len: 0);
3335 skb_reset_network_header(skb);
3336 skb_reset_transport_header(skb);
3337 skb_reset_mac_header(skb);
3338
3339 if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3340 struct fib_rt_info fri;
3341
3342 if (!res.fi) {
3343 err = fib_props[res.type].error;
3344 if (!err)
3345 err = -EHOSTUNREACH;
3346 goto errout_rcu;
3347 }
3348 fri.fi = res.fi;
3349 fri.tb_id = table_id;
3350 fri.dst = res.prefix;
3351 fri.dst_len = res.prefixlen;
3352 fri.dscp = inet_dsfield_to_dscp(dsfield: fl4.flowi4_tos);
3353 fri.type = rt->rt_type;
3354 fri.offload = 0;
3355 fri.trap = 0;
3356 fri.offload_failed = 0;
3357 if (res.fa_head) {
3358 struct fib_alias *fa;
3359
3360 hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3361 u8 slen = 32 - fri.dst_len;
3362
3363 if (fa->fa_slen == slen &&
3364 fa->tb_id == fri.tb_id &&
3365 fa->fa_dscp == fri.dscp &&
3366 fa->fa_info == res.fi &&
3367 fa->fa_type == fri.type) {
3368 fri.offload = READ_ONCE(fa->offload);
3369 fri.trap = READ_ONCE(fa->trap);
3370 fri.offload_failed =
3371 READ_ONCE(fa->offload_failed);
3372 break;
3373 }
3374 }
3375 }
3376 err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3377 seq: nlh->nlmsg_seq, RTM_NEWROUTE, fri: &fri, flags: 0);
3378 } else {
3379 err = rt_fill_info(net, dst, src, rt, table_id, fl4: &fl4, skb,
3380 NETLINK_CB(in_skb).portid,
3381 seq: nlh->nlmsg_seq, flags: 0);
3382 }
3383 if (err < 0)
3384 goto errout_rcu;
3385
3386 rcu_read_unlock();
3387
3388 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3389
3390errout_free:
3391 return err;
3392errout_rcu:
3393 rcu_read_unlock();
3394 kfree_skb(skb);
3395 goto errout_free;
3396}
3397
3398void ip_rt_multicast_event(struct in_device *in_dev)
3399{
3400 rt_cache_flush(net: dev_net(dev: in_dev->dev));
3401}
3402
3403#ifdef CONFIG_SYSCTL
3404static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3405static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3406static int ip_rt_gc_elasticity __read_mostly = 8;
3407static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3408
3409static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write,
3410 void *buffer, size_t *lenp, loff_t *ppos)
3411{
3412 struct net *net = (struct net *)__ctl->extra1;
3413
3414 if (write) {
3415 rt_cache_flush(net);
3416 fnhe_genid_bump(net);
3417 return 0;
3418 }
3419
3420 return -EINVAL;
3421}
3422
3423static struct ctl_table ipv4_route_table[] = {
3424 {
3425 .procname = "gc_thresh",
3426 .data = &ipv4_dst_ops.gc_thresh,
3427 .maxlen = sizeof(int),
3428 .mode = 0644,
3429 .proc_handler = proc_dointvec,
3430 },
3431 {
3432 .procname = "max_size",
3433 .data = &ip_rt_max_size,
3434 .maxlen = sizeof(int),
3435 .mode = 0644,
3436 .proc_handler = proc_dointvec,
3437 },
3438 {
3439 /* Deprecated. Use gc_min_interval_ms */
3440
3441 .procname = "gc_min_interval",
3442 .data = &ip_rt_gc_min_interval,
3443 .maxlen = sizeof(int),
3444 .mode = 0644,
3445 .proc_handler = proc_dointvec_jiffies,
3446 },
3447 {
3448 .procname = "gc_min_interval_ms",
3449 .data = &ip_rt_gc_min_interval,
3450 .maxlen = sizeof(int),
3451 .mode = 0644,
3452 .proc_handler = proc_dointvec_ms_jiffies,
3453 },
3454 {
3455 .procname = "gc_timeout",
3456 .data = &ip_rt_gc_timeout,
3457 .maxlen = sizeof(int),
3458 .mode = 0644,
3459 .proc_handler = proc_dointvec_jiffies,
3460 },
3461 {
3462 .procname = "gc_interval",
3463 .data = &ip_rt_gc_interval,
3464 .maxlen = sizeof(int),
3465 .mode = 0644,
3466 .proc_handler = proc_dointvec_jiffies,
3467 },
3468 {
3469 .procname = "redirect_load",
3470 .data = &ip_rt_redirect_load,
3471 .maxlen = sizeof(int),
3472 .mode = 0644,
3473 .proc_handler = proc_dointvec,
3474 },
3475 {
3476 .procname = "redirect_number",
3477 .data = &ip_rt_redirect_number,
3478 .maxlen = sizeof(int),
3479 .mode = 0644,
3480 .proc_handler = proc_dointvec,
3481 },
3482 {
3483 .procname = "redirect_silence",
3484 .data = &ip_rt_redirect_silence,
3485 .maxlen = sizeof(int),
3486 .mode = 0644,
3487 .proc_handler = proc_dointvec,
3488 },
3489 {
3490 .procname = "error_cost",
3491 .data = &ip_rt_error_cost,
3492 .maxlen = sizeof(int),
3493 .mode = 0644,
3494 .proc_handler = proc_dointvec,
3495 },
3496 {
3497 .procname = "error_burst",
3498 .data = &ip_rt_error_burst,
3499 .maxlen = sizeof(int),
3500 .mode = 0644,
3501 .proc_handler = proc_dointvec,
3502 },
3503 {
3504 .procname = "gc_elasticity",
3505 .data = &ip_rt_gc_elasticity,
3506 .maxlen = sizeof(int),
3507 .mode = 0644,
3508 .proc_handler = proc_dointvec,
3509 },
3510 { }
3511};
3512
3513static const char ipv4_route_flush_procname[] = "flush";
3514
3515static struct ctl_table ipv4_route_netns_table[] = {
3516 {
3517 .procname = ipv4_route_flush_procname,
3518 .maxlen = sizeof(int),
3519 .mode = 0200,
3520 .proc_handler = ipv4_sysctl_rtcache_flush,
3521 },
3522 {
3523 .procname = "min_pmtu",
3524 .data = &init_net.ipv4.ip_rt_min_pmtu,
3525 .maxlen = sizeof(int),
3526 .mode = 0644,
3527 .proc_handler = proc_dointvec_minmax,
3528 .extra1 = &ip_min_valid_pmtu,
3529 },
3530 {
3531 .procname = "mtu_expires",
3532 .data = &init_net.ipv4.ip_rt_mtu_expires,
3533 .maxlen = sizeof(int),
3534 .mode = 0644,
3535 .proc_handler = proc_dointvec_jiffies,
3536 },
3537 {
3538 .procname = "min_adv_mss",
3539 .data = &init_net.ipv4.ip_rt_min_advmss,
3540 .maxlen = sizeof(int),
3541 .mode = 0644,
3542 .proc_handler = proc_dointvec,
3543 },
3544 { },
3545};
3546
3547static __net_init int sysctl_route_net_init(struct net *net)
3548{
3549 struct ctl_table *tbl;
3550 size_t table_size = ARRAY_SIZE(ipv4_route_netns_table);
3551
3552 tbl = ipv4_route_netns_table;
3553 if (!net_eq(net1: net, net2: &init_net)) {
3554 int i;
3555
3556 tbl = kmemdup(p: tbl, size: sizeof(ipv4_route_netns_table), GFP_KERNEL);
3557 if (!tbl)
3558 goto err_dup;
3559
3560 /* Don't export non-whitelisted sysctls to unprivileged users */
3561 if (net->user_ns != &init_user_ns) {
3562 if (tbl[0].procname != ipv4_route_flush_procname) {
3563 tbl[0].procname = NULL;
3564 table_size = 0;
3565 }
3566 }
3567
3568 /* Update the variables to point into the current struct net
3569 * except for the first element flush
3570 */
3571 for (i = 1; i < ARRAY_SIZE(ipv4_route_netns_table) - 1; i++)
3572 tbl[i].data += (void *)net - (void *)&init_net;
3573 }
3574 tbl[0].extra1 = net;
3575
3576 net->ipv4.route_hdr = register_net_sysctl_sz(net, path: "net/ipv4/route",
3577 table: tbl, table_size);
3578 if (!net->ipv4.route_hdr)
3579 goto err_reg;
3580 return 0;
3581
3582err_reg:
3583 if (tbl != ipv4_route_netns_table)
3584 kfree(objp: tbl);
3585err_dup:
3586 return -ENOMEM;
3587}
3588
3589static __net_exit void sysctl_route_net_exit(struct net *net)
3590{
3591 struct ctl_table *tbl;
3592
3593 tbl = net->ipv4.route_hdr->ctl_table_arg;
3594 unregister_net_sysctl_table(header: net->ipv4.route_hdr);
3595 BUG_ON(tbl == ipv4_route_netns_table);
3596 kfree(objp: tbl);
3597}
3598
3599static __net_initdata struct pernet_operations sysctl_route_ops = {
3600 .init = sysctl_route_net_init,
3601 .exit = sysctl_route_net_exit,
3602};
3603#endif
3604
3605static __net_init int netns_ip_rt_init(struct net *net)
3606{
3607 /* Set default value for namespaceified sysctls */
3608 net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU;
3609 net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES;
3610 net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS;
3611 return 0;
3612}
3613
3614static struct pernet_operations __net_initdata ip_rt_ops = {
3615 .init = netns_ip_rt_init,
3616};
3617
3618static __net_init int rt_genid_init(struct net *net)
3619{
3620 atomic_set(v: &net->ipv4.rt_genid, i: 0);
3621 atomic_set(v: &net->fnhe_genid, i: 0);
3622 atomic_set(v: &net->ipv4.dev_addr_genid, i: get_random_u32());
3623 return 0;
3624}
3625
3626static __net_initdata struct pernet_operations rt_genid_ops = {
3627 .init = rt_genid_init,
3628};
3629
3630static int __net_init ipv4_inetpeer_init(struct net *net)
3631{
3632 struct inet_peer_base *bp = kmalloc(size: sizeof(*bp), GFP_KERNEL);
3633
3634 if (!bp)
3635 return -ENOMEM;
3636 inet_peer_base_init(bp);
3637 net->ipv4.peers = bp;
3638 return 0;
3639}
3640
3641static void __net_exit ipv4_inetpeer_exit(struct net *net)
3642{
3643 struct inet_peer_base *bp = net->ipv4.peers;
3644
3645 net->ipv4.peers = NULL;
3646 inetpeer_invalidate_tree(bp);
3647 kfree(objp: bp);
3648}
3649
3650static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3651 .init = ipv4_inetpeer_init,
3652 .exit = ipv4_inetpeer_exit,
3653};
3654
3655#ifdef CONFIG_IP_ROUTE_CLASSID
3656struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3657#endif /* CONFIG_IP_ROUTE_CLASSID */
3658
3659int __init ip_rt_init(void)
3660{
3661 void *idents_hash;
3662 int cpu;
3663
3664 /* For modern hosts, this will use 2 MB of memory */
3665 idents_hash = alloc_large_system_hash(tablename: "IP idents",
3666 bucketsize: sizeof(*ip_idents) + sizeof(*ip_tstamps),
3667 numentries: 0,
3668 scale: 16, /* one bucket per 64 KB */
3669 HASH_ZERO,
3670 NULL,
3671 hash_mask: &ip_idents_mask,
3672 low_limit: 2048,
3673 high_limit: 256*1024);
3674
3675 ip_idents = idents_hash;
3676
3677 get_random_bytes(buf: ip_idents, len: (ip_idents_mask + 1) * sizeof(*ip_idents));
3678
3679 ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3680
3681 for_each_possible_cpu(cpu) {
3682 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3683
3684 INIT_LIST_HEAD(list: &ul->head);
3685 INIT_LIST_HEAD(list: &ul->quarantine);
3686 spin_lock_init(&ul->lock);
3687 }
3688#ifdef CONFIG_IP_ROUTE_CLASSID
3689 ip_rt_acct = __alloc_percpu(size: 256 * sizeof(struct ip_rt_acct), align: __alignof__(struct ip_rt_acct));
3690 if (!ip_rt_acct)
3691 panic(fmt: "IP: failed to allocate ip_rt_acct\n");
3692#endif
3693
3694 ipv4_dst_ops.kmem_cachep = KMEM_CACHE(rtable,
3695 SLAB_HWCACHE_ALIGN | SLAB_PANIC);
3696
3697 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3698
3699 if (dst_entries_init(dst: &ipv4_dst_ops) < 0)
3700 panic(fmt: "IP: failed to allocate ipv4_dst_ops counter\n");
3701
3702 if (dst_entries_init(dst: &ipv4_dst_blackhole_ops) < 0)
3703 panic(fmt: "IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3704
3705 ipv4_dst_ops.gc_thresh = ~0;
3706 ip_rt_max_size = INT_MAX;
3707
3708 devinet_init();
3709 ip_fib_init();
3710
3711 if (ip_rt_proc_init())
3712 pr_err("Unable to create route proc files\n");
3713#ifdef CONFIG_XFRM
3714 xfrm_init();
3715 xfrm4_init();
3716#endif
3717 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL,
3718 flags: RTNL_FLAG_DOIT_UNLOCKED);
3719
3720#ifdef CONFIG_SYSCTL
3721 register_pernet_subsys(&sysctl_route_ops);
3722#endif
3723 register_pernet_subsys(&ip_rt_ops);
3724 register_pernet_subsys(&rt_genid_ops);
3725 register_pernet_subsys(&ipv4_inetpeer_ops);
3726 return 0;
3727}
3728
3729#ifdef CONFIG_SYSCTL
3730/*
3731 * We really need to sanitize the damn ipv4 init order, then all
3732 * this nonsense will go away.
3733 */
3734void __init ip_static_sysctl_init(void)
3735{
3736 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3737}
3738#endif
3739

source code of linux/net/ipv4/route.c