1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* INET An implementation of the TCP/IP protocol suite for the LINUX
4	* operating system. INET is implemented using the BSD Socket
5	* interface as the means of communication with the user level.
6	*
7	* ROUTE - implementation of the IP router.
8	*
9	* Authors: Ross Biro
10	* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11	* Alan Cox, <gw4pts@gw4pts.ampr.org>
12	* Linus Torvalds, <Linus.Torvalds@helsinki.fi>
13	* Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
14	*
15	* Fixes:
16	* Alan Cox : Verify area fixes.
17	* Alan Cox : cli() protects routing changes
18	* Rui Oliveira : ICMP routing table updates
19	* (rco@di.uminho.pt) Routing table insertion and update
20	* Linus Torvalds : Rewrote bits to be sensible
21	* Alan Cox : Added BSD route gw semantics
22	* Alan Cox : Super /proc >4K
23	* Alan Cox : MTU in route table
24	* Alan Cox : MSS actually. Also added the window
25	* clamper.
26	* Sam Lantinga : Fixed route matching in rt_del()
27	* Alan Cox : Routing cache support.
28	* Alan Cox : Removed compatibility cruft.
29	* Alan Cox : RTF_REJECT support.
30	* Alan Cox : TCP irtt support.
31	* Jonathan Naylor : Added Metric support.
32	* Miquel van Smoorenburg : BSD API fixes.
33	* Miquel van Smoorenburg : Metrics.
34	* Alan Cox : Use __u32 properly
35	* Alan Cox : Aligned routing errors more closely with BSD
36	* our system is still very different.
37	* Alan Cox : Faster /proc handling
38	* Alexey Kuznetsov : Massive rework to support tree based routing,
39	* routing caches and better behaviour.
40	*
41	* Olaf Erb : irtt wasn't being copied right.
42	* Bjorn Ekwall : Kerneld route support.
43	* Alan Cox : Multicast fixed (I hope)
44	* Pavel Krauz : Limited broadcast fixed
45	* Mike McLagan : Routing by source
46	* Alexey Kuznetsov : End of old history. Split to fib.c and
47	* route.c and rewritten from scratch.
48	* Andi Kleen : Load-limit warning messages.
49	* Vitaly E. Lavrov : Transparent proxy revived after year coma.
50	* Vitaly E. Lavrov : Race condition in ip_route_input_slow.
51	* Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow.
52	* Vladimir V. Ivanov : IP rule info (flowid) is really useful.
53	* Marc Boucher : routing by fwmark
54	* Robert Olsson : Added rt_cache statistics
55	* Arnaldo C. Melo : Convert proc stuff to seq_file
56	* Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
57	* Ilia Sotnikov : Ignore TOS on PMTUD and Redirect
58	* Ilia Sotnikov : Removed TOS from hash calculations
59	*/
60
61	#define pr_fmt(fmt) "IPv4: " fmt
62
63	#include <linux/module.h>
64	#include <linux/bitops.h>
65	#include <linux/kernel.h>
66	#include <linux/mm.h>
67	#include <linux/memblock.h>
68	#include <linux/socket.h>
69	#include <linux/errno.h>
70	#include <linux/in.h>
71	#include <linux/inet.h>
72	#include <linux/netdevice.h>
73	#include <linux/proc_fs.h>
74	#include <linux/init.h>
75	#include <linux/skbuff.h>
76	#include <linux/inetdevice.h>
77	#include <linux/igmp.h>
78	#include <linux/pkt_sched.h>
79	#include <linux/mroute.h>
80	#include <linux/netfilter_ipv4.h>
81	#include <linux/random.h>
82	#include <linux/rcupdate.h>
83	#include <linux/slab.h>
84	#include <linux/jhash.h>
85	#include <net/dst.h>
86	#include <net/dst_metadata.h>
87	#include <net/inet_dscp.h>
88	#include <net/net_namespace.h>
89	#include <net/ip.h>
90	#include <net/route.h>
91	#include <net/inetpeer.h>
92	#include <net/sock.h>
93	#include <net/ip_fib.h>
94	#include <net/nexthop.h>
95	#include <net/tcp.h>
96	#include <net/icmp.h>
97	#include <net/xfrm.h>
98	#include <net/lwtunnel.h>
99	#include <net/netevent.h>
100	#include <net/rtnetlink.h>
101	#ifdef CONFIG_SYSCTL
102	#include <linux/sysctl.h>
103	#endif
104	#include <net/secure_seq.h>
105	#include <net/ip_tunnels.h>
106
107	#include "fib_lookup.h"
108
109	#define RT_GC_TIMEOUT (300*HZ)
110
111	#define DEFAULT_MIN_PMTU (512 + 20 + 20)
112	#define DEFAULT_MTU_EXPIRES (10 * 60 * HZ)
113	#define DEFAULT_MIN_ADVMSS 256
114	static int ip_rt_max_size;
115	static int ip_rt_redirect_number __read_mostly = 9;
116	static int ip_rt_redirect_load __read_mostly = HZ / 50;
117	static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1));
118	static int ip_rt_error_cost __read_mostly = HZ;
119	static int ip_rt_error_burst __read_mostly = 5 * HZ;
120
121	static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT;
122
123	/*
124	* Interface to generic destination cache.
125	*/
126
127	INDIRECT_CALLABLE_SCOPE
128	struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie);
129	static unsigned int ipv4_default_advmss(const struct dst_entry *dst);
130	INDIRECT_CALLABLE_SCOPE
131	unsigned int ipv4_mtu(const struct dst_entry *dst);
132	static void ipv4_negative_advice(struct sock *sk,
133	struct dst_entry *dst);
134	static void ipv4_link_failure(struct sk_buff *skb);
135	static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
136	struct sk_buff *skb, u32 mtu,
137	bool confirm_neigh);
138	static void ip_do_redirect(struct dst_entry *dst, struct sock *sk,
139	struct sk_buff *skb);
140	static void ipv4_dst_destroy(struct dst_entry *dst);
141
142	static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
143	{
144	WARN_ON(1);
145	return NULL;
146	}
147
148	static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
149	struct sk_buff *skb,
150	const void *daddr);
151	static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr);
152
153	static struct dst_ops ipv4_dst_ops = {
154	.family = AF_INET,
155	.check = ipv4_dst_check,
156	.default_advmss = ipv4_default_advmss,
157	.mtu = ipv4_mtu,
158	.cow_metrics = ipv4_cow_metrics,
159	.destroy = ipv4_dst_destroy,
160	.negative_advice = ipv4_negative_advice,
161	.link_failure = ipv4_link_failure,
162	.update_pmtu = ip_rt_update_pmtu,
163	.redirect = ip_do_redirect,
164	.local_out = __ip_local_out,
165	.neigh_lookup = ipv4_neigh_lookup,
166	.confirm_neigh = ipv4_confirm_neigh,
167	};
168
169	#define ECN_OR_COST(class) TC_PRIO_##class
170
171	const __u8 ip_tos2prio[16] = {
172	TC_PRIO_BESTEFFORT,
173	ECN_OR_COST(BESTEFFORT),
174	TC_PRIO_BESTEFFORT,
175	ECN_OR_COST(BESTEFFORT),
176	TC_PRIO_BULK,
177	ECN_OR_COST(BULK),
178	TC_PRIO_BULK,
179	ECN_OR_COST(BULK),
180	TC_PRIO_INTERACTIVE,
181	ECN_OR_COST(INTERACTIVE),
182	TC_PRIO_INTERACTIVE,
183	ECN_OR_COST(INTERACTIVE),
184	TC_PRIO_INTERACTIVE_BULK,
185	ECN_OR_COST(INTERACTIVE_BULK),
186	TC_PRIO_INTERACTIVE_BULK,
187	ECN_OR_COST(INTERACTIVE_BULK)
188	};
189	EXPORT_SYMBOL(ip_tos2prio);
190
191	static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
192	#ifndef CONFIG_PREEMPT_RT
193	#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
194	#else
195	#define RT_CACHE_STAT_INC(field) this_cpu_inc(rt_cache_stat.field)
196	#endif
197
198	#ifdef CONFIG_PROC_FS
199	static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
200	{
201	if (*pos)
202	return NULL;
203	return SEQ_START_TOKEN;
204	}
205
206	static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
207	{
208	++*pos;
209	return NULL;
210	}
211
212	static void rt_cache_seq_stop(struct seq_file *seq, void *v)
213	{
214	}
215
216	static int rt_cache_seq_show(struct seq_file *seq, void *v)
217	{
218	if (v == SEQ_START_TOKEN)
219	seq_printf(m: seq, fmt: "%-127s\n",
220	"Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t"
221	"Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t"
222	"HHUptod\tSpecDst");
223	return 0;
224	}
225
226	static const struct seq_operations rt_cache_seq_ops = {
227	.start = rt_cache_seq_start,
228	.next = rt_cache_seq_next,
229	.stop = rt_cache_seq_stop,
230	.show = rt_cache_seq_show,
231	};
232
233	static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos)
234	{
235	int cpu;
236
237	if (*pos == 0)
238	return SEQ_START_TOKEN;
239
240	for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) {
241	if (!cpu_possible(cpu))
242	continue;
243	*pos = cpu+1;
244	return &per_cpu(rt_cache_stat, cpu);
245	}
246	return NULL;
247	}
248
249	static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
250	{
251	int cpu;
252
253	for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) {
254	if (!cpu_possible(cpu))
255	continue;
256	*pos = cpu+1;
257	return &per_cpu(rt_cache_stat, cpu);
258	}
259	(*pos)++;
260	return NULL;
261
262	}
263
264	static void rt_cpu_seq_stop(struct seq_file *seq, void *v)
265	{
266
267	}
268
269	static int rt_cpu_seq_show(struct seq_file *seq, void *v)
270	{
271	struct rt_cache_stat *st = v;
272
273	if (v == SEQ_START_TOKEN) {
274	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");
275	return 0;
276	}
277
278	seq_printf(m: seq, fmt: "%08x %08x %08x %08x %08x %08x %08x "
279	"%08x %08x %08x %08x %08x %08x "
280	"%08x %08x %08x %08x\n",
281	dst_entries_get_slow(dst: &ipv4_dst_ops),
282	0, /* st->in_hit */
283	st->in_slow_tot,
284	st->in_slow_mc,
285	st->in_no_route,
286	st->in_brd,
287	st->in_martian_dst,
288	st->in_martian_src,
289
290	0, /* st->out_hit */
291	st->out_slow_tot,
292	st->out_slow_mc,
293
294	0, /* st->gc_total */
295	0, /* st->gc_ignored */
296	0, /* st->gc_goal_miss */
297	0, /* st->gc_dst_overflow */
298	0, /* st->in_hlist_search */
299	0 /* st->out_hlist_search */
300	);
301	return 0;
302	}
303
304	static const struct seq_operations rt_cpu_seq_ops = {
305	.start = rt_cpu_seq_start,
306	.next = rt_cpu_seq_next,
307	.stop = rt_cpu_seq_stop,
308	.show = rt_cpu_seq_show,
309	};
310
311	#ifdef CONFIG_IP_ROUTE_CLASSID
312	static int rt_acct_proc_show(struct seq_file *m, void *v)
313	{
314	struct ip_rt_acct *dst, *src;
315	unsigned int i, j;
316
317	dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL);
318	if (!dst)
319	return -ENOMEM;
320
321	for_each_possible_cpu(i) {
322	src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i);
323	for (j = 0; j < 256; j++) {
324	dst[j].o_bytes += src[j].o_bytes;
325	dst[j].o_packets += src[j].o_packets;
326	dst[j].i_bytes += src[j].i_bytes;
327	dst[j].i_packets += src[j].i_packets;
328	}
329	}
330
331	seq_write(seq: m, data: dst, len: 256 * sizeof(struct ip_rt_acct));
332	kfree(objp: dst);
333	return 0;
334	}
335	#endif
336
337	static int __net_init ip_rt_do_proc_init(struct net *net)
338	{
339	struct proc_dir_entry *pde;
340
341	pde = proc_create_seq("rt_cache", 0444, net->proc_net,
342	&rt_cache_seq_ops);
343	if (!pde)
344	goto err1;
345
346	pde = proc_create_seq("rt_cache", 0444, net->proc_net_stat,
347	&rt_cpu_seq_ops);
348	if (!pde)
349	goto err2;
350
351	#ifdef CONFIG_IP_ROUTE_CLASSID
352	pde = proc_create_single("rt_acct", 0, net->proc_net,
353	rt_acct_proc_show);
354	if (!pde)
355	goto err3;
356	#endif
357	return 0;
358
359	#ifdef CONFIG_IP_ROUTE_CLASSID
360	err3:
361	remove_proc_entry("rt_cache", net->proc_net_stat);
362	#endif
363	err2:
364	remove_proc_entry("rt_cache", net->proc_net);
365	err1:
366	return -ENOMEM;
367	}
368
369	static void __net_exit ip_rt_do_proc_exit(struct net *net)
370	{
371	remove_proc_entry("rt_cache", net->proc_net_stat);
372	remove_proc_entry("rt_cache", net->proc_net);
373	#ifdef CONFIG_IP_ROUTE_CLASSID
374	remove_proc_entry("rt_acct", net->proc_net);
375	#endif
376	}
377
378	static struct pernet_operations ip_rt_proc_ops __net_initdata = {
379	.init = ip_rt_do_proc_init,
380	.exit = ip_rt_do_proc_exit,
381	};
382
383	static int __init ip_rt_proc_init(void)
384	{
385	return register_pernet_subsys(&ip_rt_proc_ops);
386	}
387
388	#else
389	static inline int ip_rt_proc_init(void)
390	{
391	return 0;
392	}
393	#endif /* CONFIG_PROC_FS */
394
395	static inline bool rt_is_expired(const struct rtable *rth)
396	{
397	bool res;
398
399	rcu_read_lock();
400	res = rth->rt_genid != rt_genid_ipv4(net: dev_net_rcu(dev: rth->dst.dev));
401	rcu_read_unlock();
402
403	return res;
404	}
405
406	void rt_cache_flush(struct net *net)
407	{
408	rt_genid_bump_ipv4(net);
409	}
410
411	static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
412	struct sk_buff *skb,
413	const void *daddr)
414	{
415	const struct rtable *rt = container_of(dst, struct rtable, dst);
416	struct net_device *dev = dst->dev;
417	struct neighbour *n;
418
419	rcu_read_lock();
420
421	if (likely(rt->rt_gw_family == AF_INET)) {
422	n = ip_neigh_gw4(dev, daddr: rt->rt_gw4);
423	} else if (rt->rt_gw_family == AF_INET6) {
424	n = ip_neigh_gw6(dev, addr: &rt->rt_gw6);
425	} else {
426	__be32 pkey;
427
428	pkey = skb ? ip_hdr(skb)->daddr : *((__be32 *) daddr);
429	n = ip_neigh_gw4(dev, daddr: pkey);
430	}
431
432	if (!IS_ERR(ptr: n) && !refcount_inc_not_zero(r: &n->refcnt))
433	n = NULL;
434
435	rcu_read_unlock();
436
437	return n;
438	}
439
440	static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
441	{
442	const struct rtable *rt = container_of(dst, struct rtable, dst);
443	struct net_device *dev = dst->dev;
444	const __be32 *pkey = daddr;
445
446	if (rt->rt_gw_family == AF_INET) {
447	pkey = (const __be32 *)&rt->rt_gw4;
448	} else if (rt->rt_gw_family == AF_INET6) {
449	return __ipv6_confirm_neigh_stub(dev, pkey: &rt->rt_gw6);
450	} else if (!daddr ||
451	(rt->rt_flags &
452	(RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL))) {
453	return;
454	}
455	__ipv4_confirm_neigh(dev, key: *(__force u32 *)pkey);
456	}
457
458	/* Hash tables of size 2048..262144 depending on RAM size.
459	* Each bucket uses 8 bytes.
460	*/
461	static u32 ip_idents_mask __read_mostly;
462	static atomic_t *ip_idents __read_mostly;
463	static u32 *ip_tstamps __read_mostly;
464
465	/* In order to protect privacy, we add a perturbation to identifiers
466	* if one generator is seldom used. This makes hard for an attacker
467	* to infer how many packets were sent between two points in time.
468	*/
469	static u32 ip_idents_reserve(u32 hash, int segs)
470	{
471	u32 bucket, old, now = (u32)jiffies;
472	atomic_t *p_id;
473	u32 *p_tstamp;
474	u32 delta = 0;
475
476	bucket = hash & ip_idents_mask;
477	p_tstamp = ip_tstamps + bucket;
478	p_id = ip_idents + bucket;
479	old = READ_ONCE(*p_tstamp);
480
481	if (old != now && cmpxchg(p_tstamp, old, now) == old)
482	delta = get_random_u32_below(ceil: now - old);
483
484	/* If UBSAN reports an error there, please make sure your compiler
485	* supports -fno-strict-overflow before reporting it that was a bug
486	* in UBSAN, and it has been fixed in GCC-8.
487	*/
488	return atomic_add_return(i: segs + delta, v: p_id) - segs;
489	}
490
491	void __ip_select_ident(struct net *net, struct iphdr *iph, int segs)
492	{
493	u32 hash, id;
494
495	/* Note the following code is not safe, but this is okay. */
496	if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
497	get_random_bytes(buf: &net->ipv4.ip_id_key,
498	len: sizeof(net->ipv4.ip_id_key));
499
500	hash = siphash_3u32(a: (__force u32)iph->daddr,
501	b: (__force u32)iph->saddr,
502	c: iph->protocol,
503	key: &net->ipv4.ip_id_key);
504	id = ip_idents_reserve(hash, segs);
505	iph->id = htons(id);
506	}
507	EXPORT_SYMBOL(__ip_select_ident);
508
509	static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
510	const struct sock *sk, const struct iphdr *iph,
511	int oif, __u8 tos, u8 prot, u32 mark,
512	int flow_flags)
513	{
514	__u8 scope = RT_SCOPE_UNIVERSE;
515
516	if (sk) {
517	oif = sk->sk_bound_dev_if;
518	mark = READ_ONCE(sk->sk_mark);
519	tos = ip_sock_rt_tos(sk);
520	scope = ip_sock_rt_scope(sk);
521	prot = inet_test_bit(HDRINCL, sk) ? IPPROTO_RAW :
522	sk->sk_protocol;
523	}
524
525	flowi4_init_output(fl4, oif, mark, tos: tos & INET_DSCP_MASK, scope,
526	proto: prot, flags: flow_flags, daddr: iph->daddr, saddr: iph->saddr, dport: 0, sport: 0,
527	uid: sock_net_uid(net, sk));
528	}
529
530	static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb,
531	const struct sock *sk)
532	{
533	const struct net *net = dev_net(dev: skb->dev);
534	const struct iphdr *iph = ip_hdr(skb);
535	int oif = skb->dev->ifindex;
536	u8 prot = iph->protocol;
537	u32 mark = skb->mark;
538	__u8 tos = iph->tos;
539
540	__build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, flow_flags: 0);
541	}
542
543	static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk)
544	{
545	const struct inet_sock *inet = inet_sk(sk);
546	const struct ip_options_rcu *inet_opt;
547	__be32 daddr = inet->inet_daddr;
548
549	rcu_read_lock();
550	inet_opt = rcu_dereference(inet->inet_opt);
551	if (inet_opt && inet_opt->opt.srr)
552	daddr = inet_opt->opt.faddr;
553	flowi4_init_output(fl4, oif: sk->sk_bound_dev_if, READ_ONCE(sk->sk_mark),
554	tos: ip_sock_rt_tos(sk),
555	scope: ip_sock_rt_scope(sk),
556	inet_test_bit(HDRINCL, sk) ?
557	IPPROTO_RAW : sk->sk_protocol,
558	flags: inet_sk_flowi_flags(sk),
559	daddr, saddr: inet->inet_saddr, dport: 0, sport: 0, uid: sk->sk_uid);
560	rcu_read_unlock();
561	}
562
563	static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
564	const struct sk_buff *skb)
565	{
566	if (skb)
567	build_skb_flow_key(fl4, skb, sk);
568	else
569	build_sk_flow_key(fl4, sk);
570	}
571
572	static DEFINE_SPINLOCK(fnhe_lock);
573
574	static void fnhe_flush_routes(struct fib_nh_exception *fnhe)
575	{
576	struct rtable *rt;
577
578	rt = rcu_dereference(fnhe->fnhe_rth_input);
579	if (rt) {
580	RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL);
581	dst_dev_put(dst: &rt->dst);
582	dst_release(dst: &rt->dst);
583	}
584	rt = rcu_dereference(fnhe->fnhe_rth_output);
585	if (rt) {
586	RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL);
587	dst_dev_put(dst: &rt->dst);
588	dst_release(dst: &rt->dst);
589	}
590	}
591
592	static void fnhe_remove_oldest(struct fnhe_hash_bucket *hash)
593	{
594	struct fib_nh_exception __rcu **fnhe_p, **oldest_p;
595	struct fib_nh_exception *fnhe, *oldest = NULL;
596
597	for (fnhe_p = &hash->chain; ; fnhe_p = &fnhe->fnhe_next) {
598	fnhe = rcu_dereference_protected(*fnhe_p,
599	lockdep_is_held(&fnhe_lock));
600	if (!fnhe)
601	break;
602	if (!oldest ||
603	time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) {
604	oldest = fnhe;
605	oldest_p = fnhe_p;
606	}
607	}
608	fnhe_flush_routes(fnhe: oldest);
609	*oldest_p = oldest->fnhe_next;
610	kfree_rcu(oldest, rcu);
611	}
612
613	static u32 fnhe_hashfun(__be32 daddr)
614	{
615	static siphash_aligned_key_t fnhe_hash_key;
616	u64 hval;
617
618	net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
619	hval = siphash_1u32(a: (__force u32)daddr, key: &fnhe_hash_key);
620	return hash_64(val: hval, FNHE_HASH_SHIFT);
621	}
622
623	static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
624	{
625	rt->rt_pmtu = fnhe->fnhe_pmtu;
626	rt->rt_mtu_locked = fnhe->fnhe_mtu_locked;
627	rt->dst.expires = fnhe->fnhe_expires;
628
629	if (fnhe->fnhe_gw) {
630	rt->rt_flags |= RTCF_REDIRECTED;
631	rt->rt_uses_gateway = 1;
632	rt->rt_gw_family = AF_INET;
633	rt->rt_gw4 = fnhe->fnhe_gw;
634	}
635	}
636
637	static void update_or_create_fnhe(struct fib_nh_common *nhc, __be32 daddr,
638	__be32 gw, u32 pmtu, bool lock,
639	unsigned long expires)
640	{
641	struct fnhe_hash_bucket *hash;
642	struct fib_nh_exception *fnhe;
643	struct rtable *rt;
644	u32 genid, hval;
645	unsigned int i;
646	int depth;
647
648	genid = fnhe_genid(net: dev_net(dev: nhc->nhc_dev));
649	hval = fnhe_hashfun(daddr);
650
651	spin_lock_bh(lock: &fnhe_lock);
652
653	hash = rcu_dereference(nhc->nhc_exceptions);
654	if (!hash) {
655	hash = kcalloc(FNHE_HASH_SIZE, sizeof(*hash), GFP_ATOMIC);
656	if (!hash)
657	goto out_unlock;
658	rcu_assign_pointer(nhc->nhc_exceptions, hash);
659	}
660
661	hash += hval;
662
663	depth = 0;
664	for (fnhe = rcu_dereference(hash->chain); fnhe;
665	fnhe = rcu_dereference(fnhe->fnhe_next)) {
666	if (fnhe->fnhe_daddr == daddr)
667	break;
668	depth++;
669	}
670
671	if (fnhe) {
672	if (fnhe->fnhe_genid != genid)
673	fnhe->fnhe_genid = genid;
674	if (gw)
675	fnhe->fnhe_gw = gw;
676	if (pmtu) {
677	fnhe->fnhe_pmtu = pmtu;
678	fnhe->fnhe_mtu_locked = lock;
679	}
680	fnhe->fnhe_expires = max(1UL, expires);
681	/* Update all cached dsts too */
682	rt = rcu_dereference(fnhe->fnhe_rth_input);
683	if (rt)
684	fill_route_from_fnhe(rt, fnhe);
685	rt = rcu_dereference(fnhe->fnhe_rth_output);
686	if (rt)
687	fill_route_from_fnhe(rt, fnhe);
688	} else {
689	/* Randomize max depth to avoid some side channels attacks. */
690	int max_depth = FNHE_RECLAIM_DEPTH +
691	get_random_u32_below(FNHE_RECLAIM_DEPTH);
692
693	while (depth > max_depth) {
694	fnhe_remove_oldest(hash);
695	depth--;
696	}
697
698	fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC);
699	if (!fnhe)
700	goto out_unlock;
701
702	fnhe->fnhe_next = hash->chain;
703
704	fnhe->fnhe_genid = genid;
705	fnhe->fnhe_daddr = daddr;
706	fnhe->fnhe_gw = gw;
707	fnhe->fnhe_pmtu = pmtu;
708	fnhe->fnhe_mtu_locked = lock;
709	fnhe->fnhe_expires = max(1UL, expires);
710
711	rcu_assign_pointer(hash->chain, fnhe);
712
713	/* Exception created; mark the cached routes for the nexthop
714	* stale, so anyone caching it rechecks if this exception
715	* applies to them.
716	*/
717	rt = rcu_dereference(nhc->nhc_rth_input);
718	if (rt)
719	rt->dst.obsolete = DST_OBSOLETE_KILL;
720
721	for_each_possible_cpu(i) {
722	struct rtable __rcu **prt;
723
724	prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
725	rt = rcu_dereference(*prt);
726	if (rt)
727	rt->dst.obsolete = DST_OBSOLETE_KILL;
728	}
729	}
730
731	fnhe->fnhe_stamp = jiffies;
732
733	out_unlock:
734	spin_unlock_bh(lock: &fnhe_lock);
735	}
736
737	static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
738	bool kill_route)
739	{
740	__be32 new_gw = icmp_hdr(skb)->un.gateway;
741	__be32 old_gw = ip_hdr(skb)->saddr;
742	struct net_device *dev = skb->dev;
743	struct in_device *in_dev;
744	struct fib_result res;
745	struct neighbour *n;
746	struct net *net;
747
748	switch (icmp_hdr(skb)->code & 7) {
749	case ICMP_REDIR_NET:
750	case ICMP_REDIR_NETTOS:
751	case ICMP_REDIR_HOST:
752	case ICMP_REDIR_HOSTTOS:
753	break;
754
755	default:
756	return;
757	}
758
759	if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
760	return;
761
762	in_dev = __in_dev_get_rcu(dev);
763	if (!in_dev)
764	return;
765
766	net = dev_net(dev);
767	if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
768	ipv4_is_multicast(addr: new_gw) || ipv4_is_lbcast(addr: new_gw) ||
769	ipv4_is_zeronet(addr: new_gw))
770	goto reject_redirect;
771
772	if (!IN_DEV_SHARED_MEDIA(in_dev)) {
773	if (!inet_addr_onlink(in_dev, a: new_gw, b: old_gw))
774	goto reject_redirect;
775	if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(gw: new_gw, dev))
776	goto reject_redirect;
777	} else {
778	if (inet_addr_type(net, addr: new_gw) != RTN_UNICAST)
779	goto reject_redirect;
780	}
781
782	n = __ipv4_neigh_lookup(dev: rt->dst.dev, key: (__force u32)new_gw);
783	if (!n)
784	n = neigh_create(tbl: &arp_tbl, pkey: &new_gw, dev: rt->dst.dev);
785	if (!IS_ERR(ptr: n)) {
786	if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
787	neigh_event_send(neigh: n, NULL);
788	} else {
789	if (fib_lookup(net, flp: fl4, res: &res, flags: 0) == 0) {
790	struct fib_nh_common *nhc;
791
792	fib_select_path(net, res: &res, fl4, skb);
793	nhc = FIB_RES_NHC(res);
794	update_or_create_fnhe(nhc, daddr: fl4->daddr, gw: new_gw,
795	pmtu: 0, lock: false,
796	expires: jiffies + ip_rt_gc_timeout);
797	}
798	if (kill_route)
799	rt->dst.obsolete = DST_OBSOLETE_KILL;
800	call_netevent_notifiers(val: NETEVENT_NEIGH_UPDATE, v: n);
801	}
802	neigh_release(neigh: n);
803	}
804	return;
805
806	reject_redirect:
807	#ifdef CONFIG_IP_ROUTE_VERBOSE
808	if (IN_DEV_LOG_MARTIANS(in_dev)) {
809	const struct iphdr *iph = (const struct iphdr *) skb->data;
810	__be32 daddr = iph->daddr;
811	__be32 saddr = iph->saddr;
812
813	net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
814	" Advised path = %pI4 -> %pI4\n",
815	&old_gw, dev->name, &new_gw,
816	&saddr, &daddr);
817	}
818	#endif
819	;
820	}
821
822	static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb)
823	{
824	struct rtable *rt;
825	struct flowi4 fl4;
826	const struct iphdr *iph = (const struct iphdr *) skb->data;
827	struct net *net = dev_net(dev: skb->dev);
828	int oif = skb->dev->ifindex;
829	u8 prot = iph->protocol;
830	u32 mark = skb->mark;
831	__u8 tos = iph->tos;
832
833	rt = dst_rtable(dst);
834
835	__build_flow_key(net, fl4: &fl4, sk, iph, oif, tos, prot, mark, flow_flags: 0);
836	__ip_do_redirect(rt, skb, fl4: &fl4, kill_route: true);
837	}
838
839	static void ipv4_negative_advice(struct sock *sk,
840	struct dst_entry *dst)
841	{
842	struct rtable *rt = dst_rtable(dst);
843
844	if ((dst->obsolete > 0) ||
845	(rt->rt_flags & RTCF_REDIRECTED) ||
846	rt->dst.expires)
847	sk_dst_reset(sk);
848	}
849
850	/*
851	* Algorithm:
852	* 1. The first ip_rt_redirect_number redirects are sent
853	* with exponential backoff, then we stop sending them at all,
854	* assuming that the host ignores our redirects.
855	* 2. If we did not see packets requiring redirects
856	* during ip_rt_redirect_silence, we assume that the host
857	* forgot redirected route and start to send redirects again.
858	*
859	* This algorithm is much cheaper and more intelligent than dumb load limiting
860	* in icmp.c.
861	*
862	* NOTE. Do not forget to inhibit load limiting for redirects (redundant)
863	* and "frag. need" (breaks PMTU discovery) in icmp.c.
864	*/
865
866	void ip_rt_send_redirect(struct sk_buff *skb)
867	{
868	struct rtable *rt = skb_rtable(skb);
869	struct in_device *in_dev;
870	struct inet_peer *peer;
871	struct net *net;
872	int log_martians;
873	int vif;
874
875	rcu_read_lock();
876	in_dev = __in_dev_get_rcu(dev: rt->dst.dev);
877	if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) {
878	rcu_read_unlock();
879	return;
880	}
881	log_martians = IN_DEV_LOG_MARTIANS(in_dev);
882	vif = l3mdev_master_ifindex_rcu(dev: rt->dst.dev);
883
884	net = dev_net(dev: rt->dst.dev);
885	peer = inet_getpeer_v4(base: net->ipv4.peers, v4daddr: ip_hdr(skb)->saddr, vif);
886	if (!peer) {
887	rcu_read_unlock();
888	icmp_send(skb_in: skb, ICMP_REDIRECT, ICMP_REDIR_HOST,
889	info: rt_nexthop(rt, daddr: ip_hdr(skb)->daddr));
890	return;
891	}
892
893	/* No redirected packets during ip_rt_redirect_silence;
894	* reset the algorithm.
895	*/
896	if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) {
897	peer->rate_tokens = 0;
898	peer->n_redirects = 0;
899	}
900
901	/* Too many ignored redirects; do not send anything
902	* set dst.rate_last to the last seen redirected packet.
903	*/
904	if (peer->n_redirects >= ip_rt_redirect_number) {
905	peer->rate_last = jiffies;
906	goto out_unlock;
907	}
908
909	/* Check for load limit; set rate_last to the latest sent
910	* redirect.
911	*/
912	if (peer->n_redirects == 0 ||
913	time_after(jiffies,
914	(peer->rate_last +
915	(ip_rt_redirect_load << peer->n_redirects)))) {
916	__be32 gw = rt_nexthop(rt, daddr: ip_hdr(skb)->daddr);
917
918	icmp_send(skb_in: skb, ICMP_REDIRECT, ICMP_REDIR_HOST, info: gw);
919	peer->rate_last = jiffies;
920	++peer->n_redirects;
921	if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians &&
922	peer->n_redirects == ip_rt_redirect_number)
923	net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
924	&ip_hdr(skb)->saddr, inet_iif(skb),
925	&ip_hdr(skb)->daddr, &gw);
926	}
927	out_unlock:
928	rcu_read_unlock();
929	}
930
931	static int ip_error(struct sk_buff *skb)
932	{
933	struct rtable *rt = skb_rtable(skb);
934	struct net_device *dev = skb->dev;
935	struct in_device *in_dev;
936	struct inet_peer *peer;
937	unsigned long now;
938	struct net *net;
939	SKB_DR(reason);
940	bool send;
941	int code;
942
943	if (netif_is_l3_master(dev: skb->dev)) {
944	dev = __dev_get_by_index(net: dev_net(dev: skb->dev), IPCB(skb)->iif);
945	if (!dev)
946	goto out;
947	}
948
949	in_dev = __in_dev_get_rcu(dev);
950
951	/* IP on this device is disabled. */
952	if (!in_dev)
953	goto out;
954
955	net = dev_net(dev: rt->dst.dev);
956	if (!IN_DEV_FORWARD(in_dev)) {
957	switch (rt->dst.error) {
958	case EHOSTUNREACH:
959	SKB_DR_SET(reason, IP_INADDRERRORS);
960	__IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS);
961	break;
962
963	case ENETUNREACH:
964	SKB_DR_SET(reason, IP_INNOROUTES);
965	__IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
966	break;
967	}
968	goto out;
969	}
970
971	switch (rt->dst.error) {
972	case EINVAL:
973	default:
974	goto out;
975	case EHOSTUNREACH:
976	code = ICMP_HOST_UNREACH;
977	break;
978	case ENETUNREACH:
979	code = ICMP_NET_UNREACH;
980	SKB_DR_SET(reason, IP_INNOROUTES);
981	__IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES);
982	break;
983	case EACCES:
984	code = ICMP_PKT_FILTERED;
985	break;
986	}
987
988	rcu_read_lock();
989	peer = inet_getpeer_v4(base: net->ipv4.peers, v4daddr: ip_hdr(skb)->saddr,
990	vif: l3mdev_master_ifindex_rcu(dev: skb->dev));
991	send = true;
992	if (peer) {
993	now = jiffies;
994	peer->rate_tokens += now - peer->rate_last;
995	if (peer->rate_tokens > ip_rt_error_burst)
996	peer->rate_tokens = ip_rt_error_burst;
997	peer->rate_last = now;
998	if (peer->rate_tokens >= ip_rt_error_cost)
999	peer->rate_tokens -= ip_rt_error_cost;
1000	else
1001	send = false;
1002	}
1003	rcu_read_unlock();
1004
1005	if (send)
1006	icmp_send(skb_in: skb, ICMP_DEST_UNREACH, code, info: 0);
1007
1008	out: kfree_skb_reason(skb, reason);
1009	return 0;
1010	}
1011
1012	static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
1013	{
1014	struct dst_entry *dst = &rt->dst;
1015	struct fib_result res;
1016	bool lock = false;
1017	struct net *net;
1018	u32 old_mtu;
1019
1020	if (ip_mtu_locked(dst))
1021	return;
1022
1023	old_mtu = ipv4_mtu(dst);
1024	if (old_mtu < mtu)
1025	return;
1026
1027	rcu_read_lock();
1028	net = dev_net_rcu(dev: dst->dev);
1029	if (mtu < net->ipv4.ip_rt_min_pmtu) {
1030	lock = true;
1031	mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
1032	}
1033
1034	if (rt->rt_pmtu == mtu && !lock &&
1035	time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
1036	goto out;
1037
1038	if (fib_lookup(net, flp: fl4, res: &res, flags: 0) == 0) {
1039	struct fib_nh_common *nhc;
1040
1041	fib_select_path(net, res: &res, fl4, NULL);
1042	#ifdef CONFIG_IP_ROUTE_MULTIPATH
1043	if (fib_info_num_path(fi: res.fi) > 1) {
1044	int nhsel;
1045
1046	for (nhsel = 0; nhsel < fib_info_num_path(fi: res.fi); nhsel++) {
1047	nhc = fib_info_nhc(fi: res.fi, nhsel);
1048	update_or_create_fnhe(nhc, daddr: fl4->daddr, gw: 0, pmtu: mtu, lock,
1049	expires: jiffies + net->ipv4.ip_rt_mtu_expires);
1050	}
1051	goto out;
1052	}
1053	#endif /* CONFIG_IP_ROUTE_MULTIPATH */
1054	nhc = FIB_RES_NHC(res);
1055	update_or_create_fnhe(nhc, daddr: fl4->daddr, gw: 0, pmtu: mtu, lock,
1056	expires: jiffies + net->ipv4.ip_rt_mtu_expires);
1057	}
1058	out:
1059	rcu_read_unlock();
1060	}
1061
1062	static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
1063	struct sk_buff *skb, u32 mtu,
1064	bool confirm_neigh)
1065	{
1066	struct rtable *rt = dst_rtable(dst);
1067	struct flowi4 fl4;
1068
1069	ip_rt_build_flow_key(fl4: &fl4, sk, skb);
1070
1071	/* Don't make lookup fail for bridged encapsulations */
1072	if (skb && netif_is_any_bridge_port(dev: skb->dev))
1073	fl4.flowi4_oif = 0;
1074
1075	__ip_rt_update_pmtu(rt, fl4: &fl4, mtu);
1076	}
1077
1078	void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
1079	int oif, u8 protocol)
1080	{
1081	const struct iphdr *iph = (const struct iphdr *)skb->data;
1082	struct flowi4 fl4;
1083	struct rtable *rt;
1084	u32 mark = IP4_REPLY_MARK(net, skb->mark);
1085
1086	__build_flow_key(net, fl4: &fl4, NULL, iph, oif, tos: iph->tos, prot: protocol, mark,
1087	flow_flags: 0);
1088	rt = __ip_route_output_key(net, flp: &fl4);
1089	if (!IS_ERR(ptr: rt)) {
1090	__ip_rt_update_pmtu(rt, fl4: &fl4, mtu);
1091	ip_rt_put(rt);
1092	}
1093	}
1094	EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
1095
1096	static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1097	{
1098	const struct iphdr *iph = (const struct iphdr *)skb->data;
1099	struct flowi4 fl4;
1100	struct rtable *rt;
1101
1102	__build_flow_key(net: sock_net(sk), fl4: &fl4, sk, iph, oif: 0, tos: 0, prot: 0, mark: 0, flow_flags: 0);
1103
1104	if (!fl4.flowi4_mark)
1105	fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark);
1106
1107	rt = __ip_route_output_key(net: sock_net(sk), flp: &fl4);
1108	if (!IS_ERR(ptr: rt)) {
1109	__ip_rt_update_pmtu(rt, fl4: &fl4, mtu);
1110	ip_rt_put(rt);
1111	}
1112	}
1113
1114	void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
1115	{
1116	const struct iphdr *iph = (const struct iphdr *)skb->data;
1117	struct flowi4 fl4;
1118	struct rtable *rt;
1119	struct dst_entry *odst = NULL;
1120	bool new = false;
1121	struct net *net = sock_net(sk);
1122
1123	bh_lock_sock(sk);
1124
1125	if (!ip_sk_accept_pmtu(sk))
1126	goto out;
1127
1128	odst = sk_dst_get(sk);
1129
1130	if (sock_owned_by_user(sk) || !odst) {
1131	__ipv4_sk_update_pmtu(skb, sk, mtu);
1132	goto out;
1133	}
1134
1135	__build_flow_key(net, fl4: &fl4, sk, iph, oif: 0, tos: 0, prot: 0, mark: 0, flow_flags: 0);
1136
1137	rt = dst_rtable(odst);
1138	if (odst->obsolete && !odst->ops->check(odst, 0)) {
1139	rt = ip_route_output_flow(sock_net(sk), flp: &fl4, sk);
1140	if (IS_ERR(ptr: rt))
1141	goto out;
1142
1143	new = true;
1144	}
1145
1146	__ip_rt_update_pmtu(dst_rtable(xfrm_dst_path(&rt->dst)), fl4: &fl4, mtu);
1147
1148	if (!dst_check(dst: &rt->dst, cookie: 0)) {
1149	if (new)
1150	dst_release(dst: &rt->dst);
1151
1152	rt = ip_route_output_flow(sock_net(sk), flp: &fl4, sk);
1153	if (IS_ERR(ptr: rt))
1154	goto out;
1155
1156	new = true;
1157	}
1158
1159	if (new)
1160	sk_dst_set(sk, dst: &rt->dst);
1161
1162	out:
1163	bh_unlock_sock(sk);
1164	dst_release(dst: odst);
1165	}
1166	EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
1167
1168	void ipv4_redirect(struct sk_buff *skb, struct net *net,
1169	int oif, u8 protocol)
1170	{
1171	const struct iphdr *iph = (const struct iphdr *)skb->data;
1172	struct flowi4 fl4;
1173	struct rtable *rt;
1174
1175	__build_flow_key(net, fl4: &fl4, NULL, iph, oif, tos: iph->tos, prot: protocol, mark: 0, flow_flags: 0);
1176	rt = __ip_route_output_key(net, flp: &fl4);
1177	if (!IS_ERR(ptr: rt)) {
1178	__ip_do_redirect(rt, skb, fl4: &fl4, kill_route: false);
1179	ip_rt_put(rt);
1180	}
1181	}
1182	EXPORT_SYMBOL_GPL(ipv4_redirect);
1183
1184	void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk)
1185	{
1186	const struct iphdr *iph = (const struct iphdr *)skb->data;
1187	struct flowi4 fl4;
1188	struct rtable *rt;
1189	struct net *net = sock_net(sk);
1190
1191	__build_flow_key(net, fl4: &fl4, sk, iph, oif: 0, tos: 0, prot: 0, mark: 0, flow_flags: 0);
1192	rt = __ip_route_output_key(net, flp: &fl4);
1193	if (!IS_ERR(ptr: rt)) {
1194	__ip_do_redirect(rt, skb, fl4: &fl4, kill_route: false);
1195	ip_rt_put(rt);
1196	}
1197	}
1198	EXPORT_SYMBOL_GPL(ipv4_sk_redirect);
1199
1200	INDIRECT_CALLABLE_SCOPE struct dst_entry *ipv4_dst_check(struct dst_entry *dst,
1201	u32 cookie)
1202	{
1203	struct rtable *rt = dst_rtable(dst);
1204
1205	/* All IPV4 dsts are created with ->obsolete set to the value
1206	* DST_OBSOLETE_FORCE_CHK which forces validation calls down
1207	* into this function always.
1208	*
1209	* When a PMTU/redirect information update invalidates a route,
1210	* this is indicated by setting obsolete to DST_OBSOLETE_KILL or
1211	* DST_OBSOLETE_DEAD.
1212	*/
1213	if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rth: rt))
1214	return NULL;
1215	return dst;
1216	}
1217	EXPORT_INDIRECT_CALLABLE(ipv4_dst_check);
1218
1219	static void ipv4_send_dest_unreach(struct sk_buff *skb)
1220	{
1221	struct net_device *dev;
1222	struct ip_options opt;
1223	int res;
1224
1225	/* Recompile ip options since IPCB may not be valid anymore.
1226	* Also check we have a reasonable ipv4 header.
1227	*/
1228	if (!pskb_network_may_pull(skb, len: sizeof(struct iphdr)) ||
1229	ip_hdr(skb)->version != 4 || ip_hdr(skb)->ihl < 5)
1230	return;
1231
1232	memset(&opt, 0, sizeof(opt));
1233	if (ip_hdr(skb)->ihl > 5) {
1234	if (!pskb_network_may_pull(skb, len: ip_hdr(skb)->ihl * 4))
1235	return;
1236	opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
1237
1238	rcu_read_lock();
1239	dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev;
1240	res = __ip_options_compile(net: dev_net(dev), opt: &opt, skb, NULL);
1241	rcu_read_unlock();
1242
1243	if (res)
1244	return;
1245	}
1246	__icmp_send(skb_in: skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, info: 0, opt: &opt);
1247	}
1248
1249	static void ipv4_link_failure(struct sk_buff *skb)
1250	{
1251	struct rtable *rt;
1252
1253	ipv4_send_dest_unreach(skb);
1254
1255	rt = skb_rtable(skb);
1256	if (rt)
1257	dst_set_expires(dst: &rt->dst, timeout: 0);
1258	}
1259
1260	static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb)
1261	{
1262	pr_debug("%s: %pI4 -> %pI4, %s\n",
1263	__func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr,
1264	skb->dev ? skb->dev->name : "?");
1265	kfree_skb(skb);
1266	WARN_ON(1);
1267	return 0;
1268	}
1269
1270	/*
1271	* We do not cache source address of outgoing interface,
1272	* because it is used only by IP RR, TS and SRR options,
1273	* so that it out of fast path.
1274	*
1275	* BTW remember: "addr" is allowed to be not aligned
1276	* in IP options!
1277	*/
1278
1279	void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt)
1280	{
1281	__be32 src;
1282
1283	if (rt_is_output_route(rt))
1284	src = ip_hdr(skb)->saddr;
1285	else {
1286	struct fib_result res;
1287	struct iphdr *iph = ip_hdr(skb);
1288	struct flowi4 fl4 = {
1289	.daddr = iph->daddr,
1290	.saddr = iph->saddr,
1291	.flowi4_tos = inet_dscp_to_dsfield(dscp: ip4h_dscp(ip4h: iph)),
1292	.flowi4_oif = rt->dst.dev->ifindex,
1293	.flowi4_iif = skb->dev->ifindex,
1294	.flowi4_mark = skb->mark,
1295	};
1296
1297	rcu_read_lock();
1298	if (fib_lookup(net: dev_net(dev: rt->dst.dev), flp: &fl4, res: &res, flags: 0) == 0)
1299	src = fib_result_prefsrc(net: dev_net(dev: rt->dst.dev), res: &res);
1300	else
1301	src = inet_select_addr(dev: rt->dst.dev,
1302	dst: rt_nexthop(rt, daddr: iph->daddr),
1303	scope: RT_SCOPE_UNIVERSE);
1304	rcu_read_unlock();
1305	}
1306	memcpy(addr, &src, 4);
1307	}
1308
1309	#ifdef CONFIG_IP_ROUTE_CLASSID
1310	static void set_class_tag(struct rtable *rt, u32 tag)
1311	{
1312	if (!(rt->dst.tclassid & 0xFFFF))
1313	rt->dst.tclassid |= tag & 0xFFFF;
1314	if (!(rt->dst.tclassid & 0xFFFF0000))
1315	rt->dst.tclassid |= tag & 0xFFFF0000;
1316	}
1317	#endif
1318
1319	static unsigned int ipv4_default_advmss(const struct dst_entry *dst)
1320	{
1321	unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr);
1322	unsigned int advmss;
1323	struct net *net;
1324
1325	rcu_read_lock();
1326	net = dev_net_rcu(dev: dst->dev);
1327	advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
1328	net->ipv4.ip_rt_min_advmss);
1329	rcu_read_unlock();
1330
1331	return min(advmss, IPV4_MAX_PMTU - header_size);
1332	}
1333
1334	INDIRECT_CALLABLE_SCOPE unsigned int ipv4_mtu(const struct dst_entry *dst)
1335	{
1336	return ip_dst_mtu_maybe_forward(dst, forwarding: false);
1337	}
1338	EXPORT_INDIRECT_CALLABLE(ipv4_mtu);
1339
1340	static void ip_del_fnhe(struct fib_nh_common *nhc, __be32 daddr)
1341	{
1342	struct fnhe_hash_bucket *hash;
1343	struct fib_nh_exception *fnhe, __rcu **fnhe_p;
1344	u32 hval = fnhe_hashfun(daddr);
1345
1346	spin_lock_bh(lock: &fnhe_lock);
1347
1348	hash = rcu_dereference_protected(nhc->nhc_exceptions,
1349	lockdep_is_held(&fnhe_lock));
1350	hash += hval;
1351
1352	fnhe_p = &hash->chain;
1353	fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
1354	while (fnhe) {
1355	if (fnhe->fnhe_daddr == daddr) {
1356	rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
1357	fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
1358	/* set fnhe_daddr to 0 to ensure it won't bind with
1359	* new dsts in rt_bind_exception().
1360	*/
1361	fnhe->fnhe_daddr = 0;
1362	fnhe_flush_routes(fnhe);
1363	kfree_rcu(fnhe, rcu);
1364	break;
1365	}
1366	fnhe_p = &fnhe->fnhe_next;
1367	fnhe = rcu_dereference_protected(fnhe->fnhe_next,
1368	lockdep_is_held(&fnhe_lock));
1369	}
1370
1371	spin_unlock_bh(lock: &fnhe_lock);
1372	}
1373
1374	static struct fib_nh_exception *find_exception(struct fib_nh_common *nhc,
1375	__be32 daddr)
1376	{
1377	struct fnhe_hash_bucket *hash = rcu_dereference(nhc->nhc_exceptions);
1378	struct fib_nh_exception *fnhe;
1379	u32 hval;
1380
1381	if (!hash)
1382	return NULL;
1383
1384	hval = fnhe_hashfun(daddr);
1385
1386	for (fnhe = rcu_dereference(hash[hval].chain); fnhe;
1387	fnhe = rcu_dereference(fnhe->fnhe_next)) {
1388	if (fnhe->fnhe_daddr == daddr) {
1389	if (fnhe->fnhe_expires &&
1390	time_after(jiffies, fnhe->fnhe_expires)) {
1391	ip_del_fnhe(nhc, daddr);
1392	break;
1393	}
1394	return fnhe;
1395	}
1396	}
1397	return NULL;
1398	}
1399
1400	/* MTU selection:
1401	* 1. mtu on route is locked - use it
1402	* 2. mtu from nexthop exception
1403	* 3. mtu from egress device
1404	*/
1405
1406	u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr)
1407	{
1408	struct fib_nh_common *nhc = res->nhc;
1409	struct net_device *dev = nhc->nhc_dev;
1410	struct fib_info *fi = res->fi;
1411	u32 mtu = 0;
1412
1413	if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) ||
1414	fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU))
1415	mtu = fi->fib_mtu;
1416
1417	if (likely(!mtu)) {
1418	struct fib_nh_exception *fnhe;
1419
1420	fnhe = find_exception(nhc, daddr);
1421	if (fnhe && !time_after_eq(jiffies, fnhe->fnhe_expires))
1422	mtu = fnhe->fnhe_pmtu;
1423	}
1424
1425	if (likely(!mtu))
1426	mtu = min(READ_ONCE(dev->mtu), IP_MAX_MTU);
1427
1428	return mtu - lwtunnel_headroom(lwtstate: nhc->nhc_lwtstate, mtu);
1429	}
1430
1431	static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
1432	__be32 daddr, const bool do_cache)
1433	{
1434	bool ret = false;
1435
1436	spin_lock_bh(lock: &fnhe_lock);
1437
1438	if (daddr == fnhe->fnhe_daddr) {
1439	struct rtable __rcu **porig;
1440	struct rtable *orig;
1441	int genid = fnhe_genid(net: dev_net(dev: rt->dst.dev));
1442
1443	if (rt_is_input_route(rt))
1444	porig = &fnhe->fnhe_rth_input;
1445	else
1446	porig = &fnhe->fnhe_rth_output;
1447	orig = rcu_dereference(*porig);
1448
1449	if (fnhe->fnhe_genid != genid) {
1450	fnhe->fnhe_genid = genid;
1451	fnhe->fnhe_gw = 0;
1452	fnhe->fnhe_pmtu = 0;
1453	fnhe->fnhe_expires = 0;
1454	fnhe->fnhe_mtu_locked = false;
1455	fnhe_flush_routes(fnhe);
1456	orig = NULL;
1457	}
1458	fill_route_from_fnhe(rt, fnhe);
1459	if (!rt->rt_gw4) {
1460	rt->rt_gw4 = daddr;
1461	rt->rt_gw_family = AF_INET;
1462	}
1463
1464	if (do_cache) {
1465	dst_hold(dst: &rt->dst);
1466	rcu_assign_pointer(*porig, rt);
1467	if (orig) {
1468	dst_dev_put(dst: &orig->dst);
1469	dst_release(dst: &orig->dst);
1470	}
1471	ret = true;
1472	}
1473
1474	fnhe->fnhe_stamp = jiffies;
1475	}
1476	spin_unlock_bh(lock: &fnhe_lock);
1477
1478	return ret;
1479	}
1480
1481	static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt)
1482	{
1483	struct rtable *orig, *prev, **p;
1484	bool ret = true;
1485
1486	if (rt_is_input_route(rt)) {
1487	p = (struct rtable **)&nhc->nhc_rth_input;
1488	} else {
1489	p = (struct rtable **)raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
1490	}
1491	orig = *p;
1492
1493	/* hold dst before doing cmpxchg() to avoid race condition
1494	* on this dst
1495	*/
1496	dst_hold(dst: &rt->dst);
1497	prev = cmpxchg(p, orig, rt);
1498	if (prev == orig) {
1499	if (orig) {
1500	rt_add_uncached_list(rt: orig);
1501	dst_release(dst: &orig->dst);
1502	}
1503	} else {
1504	dst_release(dst: &rt->dst);
1505	ret = false;
1506	}
1507
1508	return ret;
1509	}
1510
1511	struct uncached_list {
1512	spinlock_t lock;
1513	struct list_head head;
1514	};
1515
1516	static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
1517
1518	void rt_add_uncached_list(struct rtable *rt)
1519	{
1520	struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list);
1521
1522	rt->dst.rt_uncached_list = ul;
1523
1524	spin_lock_bh(lock: &ul->lock);
1525	list_add_tail(new: &rt->dst.rt_uncached, head: &ul->head);
1526	spin_unlock_bh(lock: &ul->lock);
1527	}
1528
1529	void rt_del_uncached_list(struct rtable *rt)
1530	{
1531	if (!list_empty(head: &rt->dst.rt_uncached)) {
1532	struct uncached_list *ul = rt->dst.rt_uncached_list;
1533
1534	spin_lock_bh(lock: &ul->lock);
1535	list_del_init(entry: &rt->dst.rt_uncached);
1536	spin_unlock_bh(lock: &ul->lock);
1537	}
1538	}
1539
1540	static void ipv4_dst_destroy(struct dst_entry *dst)
1541	{
1542	ip_dst_metrics_put(dst);
1543	rt_del_uncached_list(dst_rtable(dst));
1544	}
1545
1546	void rt_flush_dev(struct net_device *dev)
1547	{
1548	struct rtable *rt, *safe;
1549	int cpu;
1550
1551	for_each_possible_cpu(cpu) {
1552	struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
1553
1554	if (list_empty(head: &ul->head))
1555	continue;
1556
1557	spin_lock_bh(lock: &ul->lock);
1558	list_for_each_entry_safe(rt, safe, &ul->head, dst.rt_uncached) {
1559	if (rt->dst.dev != dev)
1560	continue;
1561	rt->dst.dev = blackhole_netdev;
1562	netdev_ref_replace(odev: dev, ndev: blackhole_netdev,
1563	tracker: &rt->dst.dev_tracker, GFP_ATOMIC);
1564	list_del_init(entry: &rt->dst.rt_uncached);
1565	}
1566	spin_unlock_bh(lock: &ul->lock);
1567	}
1568	}
1569
1570	static bool rt_cache_valid(const struct rtable *rt)
1571	{
1572	return rt &&
1573	rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
1574	!rt_is_expired(rth: rt);
1575	}
1576
1577	static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
1578	const struct fib_result *res,
1579	struct fib_nh_exception *fnhe,
1580	struct fib_info *fi, u16 type, u32 itag,
1581	const bool do_cache)
1582	{
1583	bool cached = false;
1584
1585	if (fi) {
1586	struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1587
1588	if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
1589	rt->rt_uses_gateway = 1;
1590	rt->rt_gw_family = nhc->nhc_gw_family;
1591	/* only INET and INET6 are supported */
1592	if (likely(nhc->nhc_gw_family == AF_INET))
1593	rt->rt_gw4 = nhc->nhc_gw.ipv4;
1594	else
1595	rt->rt_gw6 = nhc->nhc_gw.ipv6;
1596	}
1597
1598	ip_dst_init_metrics(dst: &rt->dst, fib_metrics: fi->fib_metrics);
1599
1600	#ifdef CONFIG_IP_ROUTE_CLASSID
1601	if (nhc->nhc_family == AF_INET) {
1602	struct fib_nh *nh;
1603
1604	nh = container_of(nhc, struct fib_nh, nh_common);
1605	rt->dst.tclassid = nh->nh_tclassid;
1606	}
1607	#endif
1608	rt->dst.lwtstate = lwtstate_get(lws: nhc->nhc_lwtstate);
1609	if (unlikely(fnhe))
1610	cached = rt_bind_exception(rt, fnhe, daddr, do_cache);
1611	else if (do_cache)
1612	cached = rt_cache_route(nhc, rt);
1613	if (unlikely(!cached)) {
1614	/* Routes we intend to cache in nexthop exception or
1615	* FIB nexthop have the DST_NOCACHE bit clear.
1616	* However, if we are unsuccessful at storing this
1617	* route into the cache we really need to set it.
1618	*/
1619	if (!rt->rt_gw4) {
1620	rt->rt_gw_family = AF_INET;
1621	rt->rt_gw4 = daddr;
1622	}
1623	rt_add_uncached_list(rt);
1624	}
1625	} else
1626	rt_add_uncached_list(rt);
1627
1628	#ifdef CONFIG_IP_ROUTE_CLASSID
1629	#ifdef CONFIG_IP_MULTIPLE_TABLES
1630	set_class_tag(rt, tag: res->tclassid);
1631	#endif
1632	set_class_tag(rt, tag: itag);
1633	#endif
1634	}
1635
1636	struct rtable *rt_dst_alloc(struct net_device *dev,
1637	unsigned int flags, u16 type,
1638	bool noxfrm)
1639	{
1640	struct rtable *rt;
1641
1642	rt = dst_alloc(ops: &ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1643	flags: (noxfrm ? DST_NOXFRM : 0));
1644
1645	if (rt) {
1646	rt->rt_genid = rt_genid_ipv4(net: dev_net(dev));
1647	rt->rt_flags = flags;
1648	rt->rt_type = type;
1649	rt->rt_is_input = 0;
1650	rt->rt_iif = 0;
1651	rt->rt_pmtu = 0;
1652	rt->rt_mtu_locked = 0;
1653	rt->rt_uses_gateway = 0;
1654	rt->rt_gw_family = 0;
1655	rt->rt_gw4 = 0;
1656
1657	rt->dst.output = ip_output;
1658	if (flags & RTCF_LOCAL)
1659	rt->dst.input = ip_local_deliver;
1660	}
1661
1662	return rt;
1663	}
1664	EXPORT_SYMBOL(rt_dst_alloc);
1665
1666	struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
1667	{
1668	struct rtable *new_rt;
1669
1670	new_rt = dst_alloc(ops: &ipv4_dst_ops, dev, DST_OBSOLETE_FORCE_CHK,
1671	flags: rt->dst.flags);
1672
1673	if (new_rt) {
1674	new_rt->rt_genid = rt_genid_ipv4(net: dev_net(dev));
1675	new_rt->rt_flags = rt->rt_flags;
1676	new_rt->rt_type = rt->rt_type;
1677	new_rt->rt_is_input = rt->rt_is_input;
1678	new_rt->rt_iif = rt->rt_iif;
1679	new_rt->rt_pmtu = rt->rt_pmtu;
1680	new_rt->rt_mtu_locked = rt->rt_mtu_locked;
1681	new_rt->rt_gw_family = rt->rt_gw_family;
1682	if (rt->rt_gw_family == AF_INET)
1683	new_rt->rt_gw4 = rt->rt_gw4;
1684	else if (rt->rt_gw_family == AF_INET6)
1685	new_rt->rt_gw6 = rt->rt_gw6;
1686
1687	new_rt->dst.input = rt->dst.input;
1688	new_rt->dst.output = rt->dst.output;
1689	new_rt->dst.error = rt->dst.error;
1690	new_rt->dst.lastuse = jiffies;
1691	new_rt->dst.lwtstate = lwtstate_get(lws: rt->dst.lwtstate);
1692	}
1693	return new_rt;
1694	}
1695	EXPORT_SYMBOL(rt_dst_clone);
1696
1697	/* called in rcu_read_lock() section */
1698	enum skb_drop_reason
1699	ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1700	dscp_t dscp, struct net_device *dev,
1701	struct in_device *in_dev, u32 *itag)
1702	{
1703	enum skb_drop_reason reason;
1704
1705	/* Primary sanity checks. */
1706	if (!in_dev)
1707	return SKB_DROP_REASON_NOT_SPECIFIED;
1708
1709	if (ipv4_is_multicast(addr: saddr) || ipv4_is_lbcast(addr: saddr))
1710	return SKB_DROP_REASON_IP_INVALID_SOURCE;
1711
1712	if (skb->protocol != htons(ETH_P_IP))
1713	return SKB_DROP_REASON_INVALID_PROTO;
1714
1715	if (ipv4_is_loopback(addr: saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
1716	return SKB_DROP_REASON_IP_LOCALNET;
1717
1718	if (ipv4_is_zeronet(addr: saddr)) {
1719	if (!ipv4_is_local_multicast(addr: daddr) &&
1720	ip_hdr(skb)->protocol != IPPROTO_IGMP)
1721	return SKB_DROP_REASON_IP_INVALID_SOURCE;
1722	} else {
1723	reason = fib_validate_source_reason(skb, src: saddr, dst: 0, dscp, oif: 0,
1724	dev, idev: in_dev, itag);
1725	if (reason)
1726	return reason;
1727	}
1728	return SKB_NOT_DROPPED_YET;
1729	}
1730
1731	/* called in rcu_read_lock() section */
1732	static enum skb_drop_reason
1733	ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
1734	dscp_t dscp, struct net_device *dev, int our)
1735	{
1736	struct in_device *in_dev = __in_dev_get_rcu(dev);
1737	unsigned int flags = RTCF_MULTICAST;
1738	enum skb_drop_reason reason;
1739	struct rtable *rth;
1740	u32 itag = 0;
1741
1742	reason = ip_mc_validate_source(skb, daddr, saddr, dscp, dev, in_dev,
1743	itag: &itag);
1744	if (reason)
1745	return reason;
1746
1747	if (our)
1748	flags |= RTCF_LOCAL;
1749
1750	if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1751	IPCB(skb)->flags |= IPSKB_NOPOLICY;
1752
1753	rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST,
1754	false);
1755	if (!rth)
1756	return SKB_DROP_REASON_NOMEM;
1757
1758	#ifdef CONFIG_IP_ROUTE_CLASSID
1759	rth->dst.tclassid = itag;
1760	#endif
1761	rth->dst.output = ip_rt_bug;
1762	rth->rt_is_input= 1;
1763
1764	#ifdef CONFIG_IP_MROUTE
1765	if (!ipv4_is_local_multicast(addr: daddr) && IN_DEV_MFORWARD(in_dev))
1766	rth->dst.input = ip_mr_input;
1767	#endif
1768	RT_CACHE_STAT_INC(in_slow_mc);
1769
1770	skb_dst_drop(skb);
1771	skb_dst_set(skb, dst: &rth->dst);
1772	return SKB_NOT_DROPPED_YET;
1773	}
1774
1775
1776	static void ip_handle_martian_source(struct net_device *dev,
1777	struct in_device *in_dev,
1778	struct sk_buff *skb,
1779	__be32 daddr,
1780	__be32 saddr)
1781	{
1782	RT_CACHE_STAT_INC(in_martian_src);
1783	#ifdef CONFIG_IP_ROUTE_VERBOSE
1784	if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) {
1785	/*
1786	* RFC1812 recommendation, if source is martian,
1787	* the only hint is MAC header.
1788	*/
1789	pr_warn("martian source %pI4 from %pI4, on dev %s\n",
1790	&daddr, &saddr, dev->name);
1791	if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
1792	print_hex_dump(KERN_WARNING, prefix_str: "ll header: ",
1793	prefix_type: DUMP_PREFIX_OFFSET, rowsize: 16, groupsize: 1,
1794	buf: skb_mac_header(skb),
1795	len: dev->hard_header_len, ascii: false);
1796	}
1797	}
1798	#endif
1799	}
1800
1801	/* called in rcu_read_lock() section */
1802	static enum skb_drop_reason
1803	__mkroute_input(struct sk_buff *skb, const struct fib_result *res,
1804	struct in_device *in_dev, __be32 daddr,
1805	__be32 saddr, dscp_t dscp)
1806	{
1807	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
1808	struct fib_nh_common *nhc = FIB_RES_NHC(*res);
1809	struct net_device *dev = nhc->nhc_dev;
1810	struct fib_nh_exception *fnhe;
1811	struct rtable *rth;
1812	int err;
1813	struct in_device *out_dev;
1814	bool do_cache;
1815	u32 itag = 0;
1816
1817	/* get a working reference to the output device */
1818	out_dev = __in_dev_get_rcu(dev);
1819	if (!out_dev) {
1820	net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n");
1821	return reason;
1822	}
1823
1824	err = fib_validate_source(skb, src: saddr, dst: daddr, dscp, FIB_RES_OIF(*res),
1825	dev: in_dev->dev, idev: in_dev, itag: &itag);
1826	if (err < 0) {
1827	reason = -err;
1828	ip_handle_martian_source(dev: in_dev->dev, in_dev, skb, daddr,
1829	saddr);
1830
1831	goto cleanup;
1832	}
1833
1834	do_cache = res->fi && !itag;
1835	if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
1836	skb->protocol == htons(ETH_P_IP)) {
1837	__be32 gw;
1838
1839	gw = nhc->nhc_gw_family == AF_INET ? nhc->nhc_gw.ipv4 : 0;
1840	if (IN_DEV_SHARED_MEDIA(out_dev) ||
1841	inet_addr_onlink(in_dev: out_dev, a: saddr, b: gw))
1842	IPCB(skb)->flags |= IPSKB_DOREDIRECT;
1843	}
1844
1845	if (skb->protocol != htons(ETH_P_IP)) {
1846	/* Not IP (i.e. ARP). Do not create route, if it is
1847	* invalid for proxy arp. DNAT routes are always valid.
1848	*
1849	* Proxy arp feature have been extended to allow, ARP
1850	* replies back to the same interface, to support
1851	* Private VLAN switch technologies. See arp.c.
1852	*/
1853	if (out_dev == in_dev &&
1854	IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) {
1855	reason = SKB_DROP_REASON_ARP_PVLAN_DISABLE;
1856	goto cleanup;
1857	}
1858	}
1859
1860	if (IN_DEV_ORCONF(in_dev, NOPOLICY))
1861	IPCB(skb)->flags |= IPSKB_NOPOLICY;
1862
1863	fnhe = find_exception(nhc, daddr);
1864	if (do_cache) {
1865	if (fnhe)
1866	rth = rcu_dereference(fnhe->fnhe_rth_input);
1867	else
1868	rth = rcu_dereference(nhc->nhc_rth_input);
1869	if (rt_cache_valid(rt: rth)) {
1870	skb_dst_set_noref(skb, dst: &rth->dst);
1871	goto out;
1872	}
1873	}
1874
1875	rth = rt_dst_alloc(out_dev->dev, 0, res->type,
1876	IN_DEV_ORCONF(out_dev, NOXFRM));
1877	if (!rth) {
1878	reason = SKB_DROP_REASON_NOMEM;
1879	goto cleanup;
1880	}
1881
1882	rth->rt_is_input = 1;
1883	RT_CACHE_STAT_INC(in_slow_tot);
1884
1885	rth->dst.input = ip_forward;
1886
1887	rt_set_nexthop(rt: rth, daddr, res, fnhe, fi: res->fi, type: res->type, itag,
1888	do_cache);
1889	lwtunnel_set_redirect(dst: &rth->dst);
1890	skb_dst_set(skb, dst: &rth->dst);
1891	out:
1892	reason = SKB_NOT_DROPPED_YET;
1893	cleanup:
1894	return reason;
1895	}
1896
1897	#ifdef CONFIG_IP_ROUTE_MULTIPATH
1898	/* To make ICMP packets follow the right flow, the multipath hash is
1899	* calculated from the inner IP addresses.
1900	*/
1901	static void ip_multipath_l3_keys(const struct sk_buff *skb,
1902	struct flow_keys *hash_keys)
1903	{
1904	const struct iphdr *outer_iph = ip_hdr(skb);
1905	const struct iphdr *key_iph = outer_iph;
1906	const struct iphdr *inner_iph;
1907	const struct icmphdr *icmph;
1908	struct iphdr _inner_iph;
1909	struct icmphdr _icmph;
1910
1911	if (likely(outer_iph->protocol != IPPROTO_ICMP))
1912	goto out;
1913
1914	if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0))
1915	goto out;
1916
1917	icmph = skb_header_pointer(skb, offset: outer_iph->ihl * 4, len: sizeof(_icmph),
1918	buffer: &_icmph);
1919	if (!icmph)
1920	goto out;
1921
1922	if (!icmp_is_err(type: icmph->type))
1923	goto out;
1924
1925	inner_iph = skb_header_pointer(skb,
1926	offset: outer_iph->ihl * 4 + sizeof(_icmph),
1927	len: sizeof(_inner_iph), buffer: &_inner_iph);
1928	if (!inner_iph)
1929	goto out;
1930
1931	key_iph = inner_iph;
1932	out:
1933	hash_keys->addrs.v4addrs.src = key_iph->saddr;
1934	hash_keys->addrs.v4addrs.dst = key_iph->daddr;
1935	}
1936
1937	static u32 fib_multipath_custom_hash_outer(const struct net *net,
1938	const struct sk_buff *skb,
1939	bool *p_has_inner)
1940	{
1941	u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1942	struct flow_keys keys, hash_keys;
1943
1944	if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
1945	return 0;
1946
1947	memset(&hash_keys, 0, sizeof(hash_keys));
1948	skb_flow_dissect_flow_keys(skb, flow: &keys, FLOW_DISSECTOR_F_STOP_AT_ENCAP);
1949
1950	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1951	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
1952	hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1953	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
1954	hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1955	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
1956	hash_keys.basic.ip_proto = keys.basic.ip_proto;
1957	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT)
1958	hash_keys.ports.src = keys.ports.src;
1959	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
1960	hash_keys.ports.dst = keys.ports.dst;
1961
1962	*p_has_inner = !!(keys.control.flags & FLOW_DIS_ENCAPSULATION);
1963	return fib_multipath_hash_from_keys(net, keys: &hash_keys);
1964	}
1965
1966	static u32 fib_multipath_custom_hash_inner(const struct net *net,
1967	const struct sk_buff *skb,
1968	bool has_inner)
1969	{
1970	u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
1971	struct flow_keys keys, hash_keys;
1972
1973	/* We assume the packet carries an encapsulation, but if none was
1974	* encountered during dissection of the outer flow, then there is no
1975	* point in calling the flow dissector again.
1976	*/
1977	if (!has_inner)
1978	return 0;
1979
1980	if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_MASK))
1981	return 0;
1982
1983	memset(&hash_keys, 0, sizeof(hash_keys));
1984	skb_flow_dissect_flow_keys(skb, flow: &keys, flags: 0);
1985
1986	if (!(keys.control.flags & FLOW_DIS_ENCAPSULATION))
1987	return 0;
1988
1989	if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
1990	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
1991	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1992	hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
1993	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
1994	hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
1995	} else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
1996	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
1997	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_IP)
1998	hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
1999	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_IP)
2000	hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2001	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_FLOWLABEL)
2002	hash_keys.tags.flow_label = keys.tags.flow_label;
2003	}
2004
2005	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_IP_PROTO)
2006	hash_keys.basic.ip_proto = keys.basic.ip_proto;
2007	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_SRC_PORT)
2008	hash_keys.ports.src = keys.ports.src;
2009	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_INNER_DST_PORT)
2010	hash_keys.ports.dst = keys.ports.dst;
2011
2012	return fib_multipath_hash_from_keys(net, keys: &hash_keys);
2013	}
2014
2015	static u32 fib_multipath_custom_hash_skb(const struct net *net,
2016	const struct sk_buff *skb)
2017	{
2018	u32 mhash, mhash_inner;
2019	bool has_inner = true;
2020
2021	mhash = fib_multipath_custom_hash_outer(net, skb, p_has_inner: &has_inner);
2022	mhash_inner = fib_multipath_custom_hash_inner(net, skb, has_inner);
2023
2024	return jhash_2words(a: mhash, b: mhash_inner, initval: 0);
2025	}
2026
2027	static u32 fib_multipath_custom_hash_fl4(const struct net *net,
2028	const struct flowi4 *fl4)
2029	{
2030	u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
2031	struct flow_keys hash_keys;
2032
2033	if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
2034	return 0;
2035
2036	memset(&hash_keys, 0, sizeof(hash_keys));
2037	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2038	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_IP)
2039	hash_keys.addrs.v4addrs.src = fl4->saddr;
2040	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_IP)
2041	hash_keys.addrs.v4addrs.dst = fl4->daddr;
2042	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_IP_PROTO)
2043	hash_keys.basic.ip_proto = fl4->flowi4_proto;
2044	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_SRC_PORT) {
2045	if (fl4->flowi4_flags & FLOWI_FLAG_ANY_SPORT)
2046	hash_keys.ports.src = (__force __be16)get_random_u16();
2047	else
2048	hash_keys.ports.src = fl4->fl4_sport;
2049	}
2050	if (hash_fields & FIB_MULTIPATH_HASH_FIELD_DST_PORT)
2051	hash_keys.ports.dst = fl4->fl4_dport;
2052
2053	return fib_multipath_hash_from_keys(net, keys: &hash_keys);
2054	}
2055
2056	/* if skb is set it will be used and fl4 can be NULL */
2057	int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
2058	const struct sk_buff *skb, struct flow_keys *flkeys)
2059	{
2060	u32 multipath_hash = fl4 ? fl4->flowi4_multipath_hash : 0;
2061	struct flow_keys hash_keys;
2062	u32 mhash = 0;
2063
2064	switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
2065	case 0:
2066	memset(&hash_keys, 0, sizeof(hash_keys));
2067	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2068	if (skb) {
2069	ip_multipath_l3_keys(skb, hash_keys: &hash_keys);
2070	} else {
2071	hash_keys.addrs.v4addrs.src = fl4->saddr;
2072	hash_keys.addrs.v4addrs.dst = fl4->daddr;
2073	}
2074	mhash = fib_multipath_hash_from_keys(net, keys: &hash_keys);
2075	break;
2076	case 1:
2077	/* skb is currently provided only when forwarding */
2078	if (skb) {
2079	unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
2080	struct flow_keys keys;
2081
2082	/* short-circuit if we already have L4 hash present */
2083	if (skb->l4_hash)
2084	return skb_get_hash_raw(skb) >> 1;
2085
2086	memset(&hash_keys, 0, sizeof(hash_keys));
2087
2088	if (!flkeys) {
2089	skb_flow_dissect_flow_keys(skb, flow: &keys, flags: flag);
2090	flkeys = &keys;
2091	}
2092
2093	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2094	hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
2095	hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
2096	hash_keys.ports.src = flkeys->ports.src;
2097	hash_keys.ports.dst = flkeys->ports.dst;
2098	hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
2099	} else {
2100	memset(&hash_keys, 0, sizeof(hash_keys));
2101	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2102	hash_keys.addrs.v4addrs.src = fl4->saddr;
2103	hash_keys.addrs.v4addrs.dst = fl4->daddr;
2104	if (fl4->flowi4_flags & FLOWI_FLAG_ANY_SPORT)
2105	hash_keys.ports.src = (__force __be16)get_random_u16();
2106	else
2107	hash_keys.ports.src = fl4->fl4_sport;
2108	hash_keys.ports.dst = fl4->fl4_dport;
2109	hash_keys.basic.ip_proto = fl4->flowi4_proto;
2110	}
2111	mhash = fib_multipath_hash_from_keys(net, keys: &hash_keys);
2112	break;
2113	case 2:
2114	memset(&hash_keys, 0, sizeof(hash_keys));
2115	/* skb is currently provided only when forwarding */
2116	if (skb) {
2117	struct flow_keys keys;
2118
2119	skb_flow_dissect_flow_keys(skb, flow: &keys, flags: 0);
2120	/* Inner can be v4 or v6 */
2121	if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV4_ADDRS) {
2122	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2123	hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
2124	hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
2125	} else if (keys.control.addr_type == FLOW_DISSECTOR_KEY_IPV6_ADDRS) {
2126	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
2127	hash_keys.addrs.v6addrs.src = keys.addrs.v6addrs.src;
2128	hash_keys.addrs.v6addrs.dst = keys.addrs.v6addrs.dst;
2129	hash_keys.tags.flow_label = keys.tags.flow_label;
2130	hash_keys.basic.ip_proto = keys.basic.ip_proto;
2131	} else {
2132	/* Same as case 0 */
2133	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2134	ip_multipath_l3_keys(skb, hash_keys: &hash_keys);
2135	}
2136	} else {
2137	/* Same as case 0 */
2138	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
2139	hash_keys.addrs.v4addrs.src = fl4->saddr;
2140	hash_keys.addrs.v4addrs.dst = fl4->daddr;
2141	}
2142	mhash = fib_multipath_hash_from_keys(net, keys: &hash_keys);
2143	break;
2144	case 3:
2145	if (skb)
2146	mhash = fib_multipath_custom_hash_skb(net, skb);
2147	else
2148	mhash = fib_multipath_custom_hash_fl4(net, fl4);
2149	break;
2150	}
2151
2152	if (multipath_hash)
2153	mhash = jhash_2words(a: mhash, b: multipath_hash, initval: 0);
2154
2155	return mhash >> 1;
2156	}
2157	#endif /* CONFIG_IP_ROUTE_MULTIPATH */
2158
2159	static enum skb_drop_reason
2160	ip_mkroute_input(struct sk_buff *skb, struct fib_result *res,
2161	struct in_device *in_dev, __be32 daddr,
2162	__be32 saddr, dscp_t dscp, struct flow_keys *hkeys)
2163	{
2164	#ifdef CONFIG_IP_ROUTE_MULTIPATH
2165	if (res->fi && fib_info_num_path(fi: res->fi) > 1) {
2166	int h = fib_multipath_hash(net: res->fi->fib_net, NULL, skb, flkeys: hkeys);
2167
2168	fib_select_multipath(res, hash: h, NULL);
2169	IPCB(skb)->flags |= IPSKB_MULTIPATH;
2170	}
2171	#endif
2172
2173	/* create a routing cache entry */
2174	return __mkroute_input(skb, res, in_dev, daddr, saddr, dscp);
2175	}
2176
2177	/* Implements all the saddr-related checks as ip_route_input_slow(),
2178	* assuming daddr is valid and the destination is not a local broadcast one.
2179	* Uses the provided hint instead of performing a route lookup.
2180	*/
2181	enum skb_drop_reason
2182	ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2183	dscp_t dscp, struct net_device *dev,
2184	const struct sk_buff *hint)
2185	{
2186	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
2187	struct in_device *in_dev = __in_dev_get_rcu(dev);
2188	struct rtable *rt = skb_rtable(skb: hint);
2189	struct net *net = dev_net(dev);
2190	u32 tag = 0;
2191
2192	if (!in_dev)
2193	return reason;
2194
2195	if (ipv4_is_multicast(addr: saddr) || ipv4_is_lbcast(addr: saddr)) {
2196	reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2197	goto martian_source;
2198	}
2199
2200	if (ipv4_is_zeronet(addr: saddr)) {
2201	reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2202	goto martian_source;
2203	}
2204
2205	if (ipv4_is_loopback(addr: saddr) && !IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
2206	reason = SKB_DROP_REASON_IP_LOCALNET;
2207	goto martian_source;
2208	}
2209
2210	if (rt->rt_type != RTN_LOCAL)
2211	goto skip_validate_source;
2212
2213	reason = fib_validate_source_reason(skb, src: saddr, dst: daddr, dscp, oif: 0, dev,
2214	idev: in_dev, itag: &tag);
2215	if (reason)
2216	goto martian_source;
2217
2218	skip_validate_source:
2219	skb_dst_copy(nskb: skb, oskb: hint);
2220	return SKB_NOT_DROPPED_YET;
2221
2222	martian_source:
2223	ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2224	return reason;
2225	}
2226
2227	/* get device for dst_alloc with local routes */
2228	static struct net_device *ip_rt_get_dev(struct net *net,
2229	const struct fib_result *res)
2230	{
2231	struct fib_nh_common *nhc = res->fi ? res->nhc : NULL;
2232	struct net_device *dev = NULL;
2233
2234	if (nhc)
2235	dev = l3mdev_master_dev_rcu(dev: nhc->nhc_dev);
2236
2237	return dev ? : net->loopback_dev;
2238	}
2239
2240	/*
2241	* NOTE. We drop all the packets that has local source
2242	* addresses, because every properly looped back packet
2243	* must have correct destination already attached by output routine.
2244	* Changes in the enforced policies must be applied also to
2245	* ip_route_use_hint().
2246	*
2247	* Such approach solves two big problems:
2248	* 1. Not simplex devices are handled properly.
2249	* 2. IP spoofing attempts are filtered with 100% of guarantee.
2250	* called with rcu_read_lock()
2251	*/
2252
2253	static enum skb_drop_reason
2254	ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2255	dscp_t dscp, struct net_device *dev,
2256	struct fib_result *res)
2257	{
2258	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
2259	struct in_device *in_dev = __in_dev_get_rcu(dev);
2260	struct flow_keys *flkeys = NULL, _flkeys;
2261	struct net *net = dev_net(dev);
2262	struct ip_tunnel_info *tun_info;
2263	int err = -EINVAL;
2264	unsigned int flags = 0;
2265	u32 itag = 0;
2266	struct rtable *rth;
2267	struct flowi4 fl4;
2268	bool do_cache = true;
2269
2270	/* IP on this device is disabled. */
2271
2272	if (!in_dev)
2273	goto out;
2274
2275	/* Check for the most weird martians, which can be not detected
2276	* by fib_lookup.
2277	*/
2278
2279	tun_info = skb_tunnel_info(skb);
2280	if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX))
2281	fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
2282	else
2283	fl4.flowi4_tun_key.tun_id = 0;
2284	skb_dst_drop(skb);
2285
2286	if (ipv4_is_multicast(addr: saddr) || ipv4_is_lbcast(addr: saddr)) {
2287	reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2288	goto martian_source;
2289	}
2290
2291	res->fi = NULL;
2292	res->table = NULL;
2293	if (ipv4_is_lbcast(addr: daddr) || (saddr == 0 && daddr == 0))
2294	goto brd_input;
2295
2296	/* Accept zero addresses only to limited broadcast;
2297	* I even do not know to fix it or not. Waiting for complains :-)
2298	*/
2299	if (ipv4_is_zeronet(addr: saddr)) {
2300	reason = SKB_DROP_REASON_IP_INVALID_SOURCE;
2301	goto martian_source;
2302	}
2303
2304	if (ipv4_is_zeronet(addr: daddr)) {
2305	reason = SKB_DROP_REASON_IP_INVALID_DEST;
2306	goto martian_destination;
2307	}
2308
2309	/* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(),
2310	* and call it once if daddr or/and saddr are loopback addresses
2311	*/
2312	if (ipv4_is_loopback(addr: daddr)) {
2313	if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
2314	reason = SKB_DROP_REASON_IP_LOCALNET;
2315	goto martian_destination;
2316	}
2317	} else if (ipv4_is_loopback(addr: saddr)) {
2318	if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) {
2319	reason = SKB_DROP_REASON_IP_LOCALNET;
2320	goto martian_source;
2321	}
2322	}
2323
2324	/*
2325	* Now we are ready to route packet.
2326	*/
2327	fl4.flowi4_l3mdev = 0;
2328	fl4.flowi4_oif = 0;
2329	fl4.flowi4_iif = dev->ifindex;
2330	fl4.flowi4_mark = skb->mark;
2331	fl4.flowi4_tos = inet_dscp_to_dsfield(dscp);
2332	fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
2333	fl4.flowi4_flags = 0;
2334	fl4.daddr = daddr;
2335	fl4.saddr = saddr;
2336	fl4.flowi4_uid = sock_net_uid(net, NULL);
2337	fl4.flowi4_multipath_hash = 0;
2338
2339	if (fib4_rules_early_flow_dissect(net, skb, fl4: &fl4, flkeys: &_flkeys)) {
2340	flkeys = &_flkeys;
2341	} else {
2342	fl4.flowi4_proto = 0;
2343	fl4.fl4_sport = 0;
2344	fl4.fl4_dport = 0;
2345	}
2346
2347	err = fib_lookup(net, flp: &fl4, res, flags: 0);
2348	if (err != 0) {
2349	if (!IN_DEV_FORWARD(in_dev))
2350	err = -EHOSTUNREACH;
2351	goto no_route;
2352	}
2353
2354	if (res->type == RTN_BROADCAST) {
2355	if (IN_DEV_BFORWARD(in_dev))
2356	goto make_route;
2357	/* not do cache if bc_forwarding is enabled */
2358	if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING))
2359	do_cache = false;
2360	goto brd_input;
2361	}
2362
2363	err = -EINVAL;
2364	if (res->type == RTN_LOCAL) {
2365	reason = fib_validate_source_reason(skb, src: saddr, dst: daddr, dscp,
2366	oif: 0, dev, idev: in_dev, itag: &itag);
2367	if (reason)
2368	goto martian_source;
2369	goto local_input;
2370	}
2371
2372	if (!IN_DEV_FORWARD(in_dev)) {
2373	err = -EHOSTUNREACH;
2374	goto no_route;
2375	}
2376	if (res->type != RTN_UNICAST) {
2377	reason = SKB_DROP_REASON_IP_INVALID_DEST;
2378	goto martian_destination;
2379	}
2380
2381	make_route:
2382	reason = ip_mkroute_input(skb, res, in_dev, daddr, saddr, dscp,
2383	hkeys: flkeys);
2384
2385	out:
2386	return reason;
2387
2388	brd_input:
2389	if (skb->protocol != htons(ETH_P_IP)) {
2390	reason = SKB_DROP_REASON_INVALID_PROTO;
2391	goto out;
2392	}
2393
2394	if (!ipv4_is_zeronet(addr: saddr)) {
2395	reason = fib_validate_source_reason(skb, src: saddr, dst: 0, dscp, oif: 0,
2396	dev, idev: in_dev, itag: &itag);
2397	if (reason)
2398	goto martian_source;
2399	}
2400	flags |= RTCF_BROADCAST;
2401	res->type = RTN_BROADCAST;
2402	RT_CACHE_STAT_INC(in_brd);
2403
2404	local_input:
2405	if (IN_DEV_ORCONF(in_dev, NOPOLICY))
2406	IPCB(skb)->flags |= IPSKB_NOPOLICY;
2407
2408	do_cache &= res->fi && !itag;
2409	if (do_cache) {
2410	struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2411
2412	rth = rcu_dereference(nhc->nhc_rth_input);
2413	if (rt_cache_valid(rt: rth)) {
2414	skb_dst_set_noref(skb, dst: &rth->dst);
2415	reason = SKB_NOT_DROPPED_YET;
2416	goto out;
2417	}
2418	}
2419
2420	rth = rt_dst_alloc(ip_rt_get_dev(net, res),
2421	flags | RTCF_LOCAL, res->type, false);
2422	if (!rth)
2423	goto e_nobufs;
2424
2425	rth->dst.output= ip_rt_bug;
2426	#ifdef CONFIG_IP_ROUTE_CLASSID
2427	rth->dst.tclassid = itag;
2428	#endif
2429	rth->rt_is_input = 1;
2430
2431	RT_CACHE_STAT_INC(in_slow_tot);
2432	if (res->type == RTN_UNREACHABLE) {
2433	rth->dst.input= ip_error;
2434	rth->dst.error= -err;
2435	rth->rt_flags &= ~RTCF_LOCAL;
2436	}
2437
2438	if (do_cache) {
2439	struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2440
2441	rth->dst.lwtstate = lwtstate_get(lws: nhc->nhc_lwtstate);
2442	if (lwtunnel_input_redirect(lwtstate: rth->dst.lwtstate)) {
2443	WARN_ON(rth->dst.input == lwtunnel_input);
2444	rth->dst.lwtstate->orig_input = rth->dst.input;
2445	rth->dst.input = lwtunnel_input;
2446	}
2447
2448	if (unlikely(!rt_cache_route(nhc, rth)))
2449	rt_add_uncached_list(rt: rth);
2450	}
2451	skb_dst_set(skb, dst: &rth->dst);
2452	reason = SKB_NOT_DROPPED_YET;
2453	goto out;
2454
2455	no_route:
2456	RT_CACHE_STAT_INC(in_no_route);
2457	res->type = RTN_UNREACHABLE;
2458	res->fi = NULL;
2459	res->table = NULL;
2460	goto local_input;
2461
2462	/*
2463	* Do not cache martian addresses: they should be logged (RFC1812)
2464	*/
2465	martian_destination:
2466	RT_CACHE_STAT_INC(in_martian_dst);
2467	#ifdef CONFIG_IP_ROUTE_VERBOSE
2468	if (IN_DEV_LOG_MARTIANS(in_dev))
2469	net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n",
2470	&daddr, &saddr, dev->name);
2471	#endif
2472	goto out;
2473
2474	e_nobufs:
2475	reason = SKB_DROP_REASON_NOMEM;
2476	goto out;
2477
2478	martian_source:
2479	ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
2480	goto out;
2481	}
2482
2483	/* called with rcu_read_lock held */
2484	static enum skb_drop_reason
2485	ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,
2486	dscp_t dscp, struct net_device *dev,
2487	struct fib_result *res)
2488	{
2489	/* Multicast recognition logic is moved from route cache to here.
2490	* The problem was that too many Ethernet cards have broken/missing
2491	* hardware multicast filters :-( As result the host on multicasting
2492	* network acquires a lot of useless route cache entries, sort of
2493	* SDR messages from all the world. Now we try to get rid of them.
2494	* Really, provided software IP multicast filter is organized
2495	* reasonably (at least, hashed), it does not result in a slowdown
2496	* comparing with route cache reject entries.
2497	* Note, that multicast routers are not affected, because
2498	* route cache entry is created eventually.
2499	*/
2500	if (ipv4_is_multicast(addr: daddr)) {
2501	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
2502	struct in_device *in_dev = __in_dev_get_rcu(dev);
2503	int our = 0;
2504
2505	if (!in_dev)
2506	return reason;
2507
2508	our = ip_check_mc_rcu(dev: in_dev, mc_addr: daddr, src_addr: saddr,
2509	proto: ip_hdr(skb)->protocol);
2510
2511	/* check l3 master if no match yet */
2512	if (!our && netif_is_l3_slave(dev)) {
2513	struct in_device *l3_in_dev;
2514
2515	l3_in_dev = __in_dev_get_rcu(dev: skb->dev);
2516	if (l3_in_dev)
2517	our = ip_check_mc_rcu(dev: l3_in_dev, mc_addr: daddr, src_addr: saddr,
2518	proto: ip_hdr(skb)->protocol);
2519	}
2520
2521	if (our
2522	#ifdef CONFIG_IP_MROUTE
2523	||
2524	(!ipv4_is_local_multicast(addr: daddr) &&
2525	IN_DEV_MFORWARD(in_dev))
2526	#endif
2527	) {
2528	reason = ip_route_input_mc(skb, daddr, saddr, dscp,
2529	dev, our);
2530	}
2531	return reason;
2532	}
2533
2534	return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res);
2535	}
2536
2537	enum skb_drop_reason ip_route_input_noref(struct sk_buff *skb, __be32 daddr,
2538	__be32 saddr, dscp_t dscp,
2539	struct net_device *dev)
2540	{
2541	enum skb_drop_reason reason;
2542	struct fib_result res;
2543
2544	rcu_read_lock();
2545	reason = ip_route_input_rcu(skb, daddr, saddr, dscp, dev, res: &res);
2546	rcu_read_unlock();
2547
2548	return reason;
2549	}
2550	EXPORT_SYMBOL(ip_route_input_noref);
2551
2552	/* called with rcu_read_lock() */
2553	static struct rtable *__mkroute_output(const struct fib_result *res,
2554	const struct flowi4 *fl4, int orig_oif,
2555	struct net_device *dev_out,
2556	unsigned int flags)
2557	{
2558	struct fib_info *fi = res->fi;
2559	struct fib_nh_exception *fnhe;
2560	struct in_device *in_dev;
2561	u16 type = res->type;
2562	struct rtable *rth;
2563	bool do_cache;
2564
2565	in_dev = __in_dev_get_rcu(dev: dev_out);
2566	if (!in_dev)
2567	return ERR_PTR(error: -EINVAL);
2568
2569	if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev)))
2570	if (ipv4_is_loopback(addr: fl4->saddr) &&
2571	!(dev_out->flags & IFF_LOOPBACK) &&
2572	!netif_is_l3_master(dev: dev_out))
2573	return ERR_PTR(error: -EINVAL);
2574
2575	if (ipv4_is_lbcast(addr: fl4->daddr))
2576	type = RTN_BROADCAST;
2577	else if (ipv4_is_multicast(addr: fl4->daddr))
2578	type = RTN_MULTICAST;
2579	else if (ipv4_is_zeronet(addr: fl4->daddr))
2580	return ERR_PTR(error: -EINVAL);
2581
2582	if (dev_out->flags & IFF_LOOPBACK)
2583	flags |= RTCF_LOCAL;
2584
2585	do_cache = true;
2586	if (type == RTN_BROADCAST) {
2587	flags |= RTCF_BROADCAST | RTCF_LOCAL;
2588	fi = NULL;
2589	} else if (type == RTN_MULTICAST) {
2590	flags |= RTCF_MULTICAST | RTCF_LOCAL;
2591	if (!ip_check_mc_rcu(dev: in_dev, mc_addr: fl4->daddr, src_addr: fl4->saddr,
2592	proto: fl4->flowi4_proto))
2593	flags &= ~RTCF_LOCAL;
2594	else
2595	do_cache = false;
2596	/* If multicast route do not exist use
2597	* default one, but do not gateway in this case.
2598	* Yes, it is hack.
2599	*/
2600	if (fi && res->prefixlen < 4)
2601	fi = NULL;
2602	} else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
2603	(orig_oif != dev_out->ifindex)) {
2604	/* For local routes that require a particular output interface
2605	* we do not want to cache the result. Caching the result
2606	* causes incorrect behaviour when there are multiple source
2607	* addresses on the interface, the end result being that if the
2608	* intended recipient is waiting on that interface for the
2609	* packet he won't receive it because it will be delivered on
2610	* the loopback interface and the IP_PKTINFO ipi_ifindex will
2611	* be set to the loopback interface as well.
2612	*/
2613	do_cache = false;
2614	}
2615
2616	fnhe = NULL;
2617	do_cache &= fi != NULL;
2618	if (fi) {
2619	struct fib_nh_common *nhc = FIB_RES_NHC(*res);
2620	struct rtable __rcu **prth;
2621
2622	fnhe = find_exception(nhc, daddr: fl4->daddr);
2623	if (!do_cache)
2624	goto add;
2625	if (fnhe) {
2626	prth = &fnhe->fnhe_rth_output;
2627	} else {
2628	if (unlikely(fl4->flowi4_flags &
2629	FLOWI_FLAG_KNOWN_NH &&
2630	!(nhc->nhc_gw_family &&
2631	nhc->nhc_scope == RT_SCOPE_LINK))) {
2632	do_cache = false;
2633	goto add;
2634	}
2635	prth = raw_cpu_ptr(nhc->nhc_pcpu_rth_output);
2636	}
2637	rth = rcu_dereference(*prth);
2638	if (rt_cache_valid(rt: rth) && dst_hold_safe(dst: &rth->dst))
2639	return rth;
2640	}
2641
2642	add:
2643	rth = rt_dst_alloc(dev_out, flags, type,
2644	IN_DEV_ORCONF(in_dev, NOXFRM));
2645	if (!rth)
2646	return ERR_PTR(error: -ENOBUFS);
2647
2648	rth->rt_iif = orig_oif;
2649
2650	RT_CACHE_STAT_INC(out_slow_tot);
2651
2652	if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) {
2653	if (flags & RTCF_LOCAL &&
2654	!(dev_out->flags & IFF_LOOPBACK)) {
2655	rth->dst.output = ip_mc_output;
2656	RT_CACHE_STAT_INC(out_slow_mc);
2657	}
2658	#ifdef CONFIG_IP_MROUTE
2659	if (type == RTN_MULTICAST) {
2660	if (IN_DEV_MFORWARD(in_dev) &&
2661	!ipv4_is_local_multicast(addr: fl4->daddr)) {
2662	rth->dst.input = ip_mr_input;
2663	rth->dst.output = ip_mc_output;
2664	}
2665	}
2666	#endif
2667	}
2668
2669	rt_set_nexthop(rt: rth, daddr: fl4->daddr, res, fnhe, fi, type, itag: 0, do_cache);
2670	lwtunnel_set_redirect(dst: &rth->dst);
2671
2672	return rth;
2673	}
2674
2675	/*
2676	* Major route resolver routine.
2677	*/
2678
2679	struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4,
2680	const struct sk_buff *skb)
2681	{
2682	struct fib_result res = {
2683	.type = RTN_UNSPEC,
2684	.fi = NULL,
2685	.table = NULL,
2686	.tclassid = 0,
2687	};
2688	struct rtable *rth;
2689
2690	fl4->flowi4_iif = LOOPBACK_IFINDEX;
2691	fl4->flowi4_tos &= INET_DSCP_MASK;
2692
2693	rcu_read_lock();
2694	rth = ip_route_output_key_hash_rcu(net, flp: fl4, res: &res, skb);
2695	rcu_read_unlock();
2696
2697	return rth;
2698	}
2699	EXPORT_SYMBOL_GPL(ip_route_output_key_hash);
2700
2701	struct rtable *ip_route_output_key_hash_rcu(struct net *net, struct flowi4 *fl4,
2702	struct fib_result *res,
2703	const struct sk_buff *skb)
2704	{
2705	struct net_device *dev_out = NULL;
2706	int orig_oif = fl4->flowi4_oif;
2707	unsigned int flags = 0;
2708	struct rtable *rth;
2709	int err;
2710
2711	if (fl4->saddr) {
2712	if (ipv4_is_multicast(addr: fl4->saddr) ||
2713	ipv4_is_lbcast(addr: fl4->saddr)) {
2714	rth = ERR_PTR(error: -EINVAL);
2715	goto out;
2716	}
2717
2718	rth = ERR_PTR(error: -ENETUNREACH);
2719
2720	/* I removed check for oif == dev_out->oif here.
2721	* It was wrong for two reasons:
2722	* 1. ip_dev_find(net, saddr) can return wrong iface, if saddr
2723	* is assigned to multiple interfaces.
2724	* 2. Moreover, we are allowed to send packets with saddr
2725	* of another iface. --ANK
2726	*/
2727
2728	if (fl4->flowi4_oif == 0 &&
2729	(ipv4_is_multicast(addr: fl4->daddr) ||
2730	ipv4_is_lbcast(addr: fl4->daddr))) {
2731	/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2732	dev_out = __ip_dev_find(net, addr: fl4->saddr, devref: false);
2733	if (!dev_out)
2734	goto out;
2735
2736	/* Special hack: user can direct multicasts
2737	* and limited broadcast via necessary interface
2738	* without fiddling with IP_MULTICAST_IF or IP_PKTINFO.
2739	* This hack is not just for fun, it allows
2740	* vic,vat and friends to work.
2741	* They bind socket to loopback, set ttl to zero
2742	* and expect that it will work.
2743	* From the viewpoint of routing cache they are broken,
2744	* because we are not allowed to build multicast path
2745	* with loopback source addr (look, routing cache
2746	* cannot know, that ttl is zero, so that packet
2747	* will not leave this host and route is valid).
2748	* Luckily, this hack is good workaround.
2749	*/
2750
2751	fl4->flowi4_oif = dev_out->ifindex;
2752	goto make_route;
2753	}
2754
2755	if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) {
2756	/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
2757	if (!__ip_dev_find(net, addr: fl4->saddr, devref: false))
2758	goto out;
2759	}
2760	}
2761
2762
2763	if (fl4->flowi4_oif) {
2764	dev_out = dev_get_by_index_rcu(net, ifindex: fl4->flowi4_oif);
2765	rth = ERR_PTR(error: -ENODEV);
2766	if (!dev_out)
2767	goto out;
2768
2769	/* RACE: Check return value of inet_select_addr instead. */
2770	if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev: dev_out)) {
2771	rth = ERR_PTR(error: -ENETUNREACH);
2772	goto out;
2773	}
2774	if (ipv4_is_local_multicast(addr: fl4->daddr) ||
2775	ipv4_is_lbcast(addr: fl4->daddr) ||
2776	fl4->flowi4_proto == IPPROTO_IGMP) {
2777	if (!fl4->saddr)
2778	fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2779	scope: RT_SCOPE_LINK);
2780	goto make_route;
2781	}
2782	if (!fl4->saddr) {
2783	if (ipv4_is_multicast(addr: fl4->daddr))
2784	fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2785	scope: fl4->flowi4_scope);
2786	else if (!fl4->daddr)
2787	fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2788	scope: RT_SCOPE_HOST);
2789	}
2790	}
2791
2792	if (!fl4->daddr) {
2793	fl4->daddr = fl4->saddr;
2794	if (!fl4->daddr)
2795	fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK);
2796	dev_out = net->loopback_dev;
2797	fl4->flowi4_oif = LOOPBACK_IFINDEX;
2798	res->type = RTN_LOCAL;
2799	flags |= RTCF_LOCAL;
2800	goto make_route;
2801	}
2802
2803	err = fib_lookup(net, flp: fl4, res, flags: 0);
2804	if (err) {
2805	res->fi = NULL;
2806	res->table = NULL;
2807	if (fl4->flowi4_oif &&
2808	(ipv4_is_multicast(addr: fl4->daddr) || !fl4->flowi4_l3mdev)) {
2809	/* Apparently, routing tables are wrong. Assume,
2810	* that the destination is on link.
2811	*
2812	* WHY? DW.
2813	* Because we are allowed to send to iface
2814	* even if it has NO routes and NO assigned
2815	* addresses. When oif is specified, routing
2816	* tables are looked up with only one purpose:
2817	* to catch if destination is gatewayed, rather than
2818	* direct. Moreover, if MSG_DONTROUTE is set,
2819	* we send packet, ignoring both routing tables
2820	* and ifaddr state. --ANK
2821	*
2822	*
2823	* We could make it even if oif is unknown,
2824	* likely IPv6, but we do not.
2825	*/
2826
2827	if (fl4->saddr == 0)
2828	fl4->saddr = inet_select_addr(dev: dev_out, dst: 0,
2829	scope: RT_SCOPE_LINK);
2830	res->type = RTN_UNICAST;
2831	goto make_route;
2832	}
2833	rth = ERR_PTR(error: err);
2834	goto out;
2835	}
2836
2837	if (res->type == RTN_LOCAL) {
2838	if (!fl4->saddr) {
2839	if (res->fi->fib_prefsrc)
2840	fl4->saddr = res->fi->fib_prefsrc;
2841	else
2842	fl4->saddr = fl4->daddr;
2843	}
2844
2845	/* L3 master device is the loopback for that domain */
2846	dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) ? :
2847	net->loopback_dev;
2848
2849	/* make sure orig_oif points to fib result device even
2850	* though packet rx/tx happens over loopback or l3mdev
2851	*/
2852	orig_oif = FIB_RES_OIF(*res);
2853
2854	fl4->flowi4_oif = dev_out->ifindex;
2855	flags |= RTCF_LOCAL;
2856	goto make_route;
2857	}
2858
2859	fib_select_path(net, res, fl4, skb);
2860
2861	dev_out = FIB_RES_DEV(*res);
2862
2863	make_route:
2864	rth = __mkroute_output(res, fl4, orig_oif, dev_out, flags);
2865
2866	out:
2867	return rth;
2868	}
2869
2870	static struct dst_ops ipv4_dst_blackhole_ops = {
2871	.family = AF_INET,
2872	.default_advmss = ipv4_default_advmss,
2873	.neigh_lookup = ipv4_neigh_lookup,
2874	.check = dst_blackhole_check,
2875	.cow_metrics = dst_blackhole_cow_metrics,
2876	.update_pmtu = dst_blackhole_update_pmtu,
2877	.redirect = dst_blackhole_redirect,
2878	.mtu = dst_blackhole_mtu,
2879	};
2880
2881	struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)
2882	{
2883	struct rtable *ort = dst_rtable(dst_orig);
2884	struct rtable *rt;
2885
2886	rt = dst_alloc(ops: &ipv4_dst_blackhole_ops, NULL, DST_OBSOLETE_DEAD, flags: 0);
2887	if (rt) {
2888	struct dst_entry *new = &rt->dst;
2889
2890	new->__use = 1;
2891	new->input = dst_discard;
2892	new->output = dst_discard_out;
2893
2894	new->dev = net->loopback_dev;
2895	netdev_hold(dev: new->dev, tracker: &new->dev_tracker, GFP_ATOMIC);
2896
2897	rt->rt_is_input = ort->rt_is_input;
2898	rt->rt_iif = ort->rt_iif;
2899	rt->rt_pmtu = ort->rt_pmtu;
2900	rt->rt_mtu_locked = ort->rt_mtu_locked;
2901
2902	rt->rt_genid = rt_genid_ipv4(net);
2903	rt->rt_flags = ort->rt_flags;
2904	rt->rt_type = ort->rt_type;
2905	rt->rt_uses_gateway = ort->rt_uses_gateway;
2906	rt->rt_gw_family = ort->rt_gw_family;
2907	if (rt->rt_gw_family == AF_INET)
2908	rt->rt_gw4 = ort->rt_gw4;
2909	else if (rt->rt_gw_family == AF_INET6)
2910	rt->rt_gw6 = ort->rt_gw6;
2911	}
2912
2913	dst_release(dst: dst_orig);
2914
2915	return rt ? &rt->dst : ERR_PTR(error: -ENOMEM);
2916	}
2917
2918	struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4,
2919	const struct sock *sk)
2920	{
2921	struct rtable *rt = __ip_route_output_key(net, flp: flp4);
2922
2923	if (IS_ERR(ptr: rt))
2924	return rt;
2925
2926	if (flp4->flowi4_proto) {
2927	flp4->flowi4_oif = rt->dst.dev->ifindex;
2928	rt = dst_rtable(xfrm_lookup_route(net, &rt->dst,
2929	flowi4_to_flowi(flp4),
2930	sk, 0));
2931	}
2932
2933	return rt;
2934	}
2935	EXPORT_SYMBOL_GPL(ip_route_output_flow);
2936
2937	/* called with rcu_read_lock held */
2938	static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
2939	struct rtable *rt, u32 table_id, dscp_t dscp,
2940	struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
2941	u32 seq, unsigned int flags)
2942	{
2943	struct rtmsg *r;
2944	struct nlmsghdr *nlh;
2945	unsigned long expires = 0;
2946	u32 error;
2947	u32 metrics[RTAX_MAX];
2948
2949	nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, payload: sizeof(*r), flags);
2950	if (!nlh)
2951	return -EMSGSIZE;
2952
2953	r = nlmsg_data(nlh);
2954	r->rtm_family = AF_INET;
2955	r->rtm_dst_len = 32;
2956	r->rtm_src_len = 0;
2957	r->rtm_tos = inet_dscp_to_dsfield(dscp);
2958	r->rtm_table = table_id < 256 ? table_id : RT_TABLE_COMPAT;
2959	if (nla_put_u32(skb, attrtype: RTA_TABLE, value: table_id))
2960	goto nla_put_failure;
2961	r->rtm_type = rt->rt_type;
2962	r->rtm_scope = RT_SCOPE_UNIVERSE;
2963	r->rtm_protocol = RTPROT_UNSPEC;
2964	r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
2965	if (rt->rt_flags & RTCF_NOTIFY)
2966	r->rtm_flags |= RTM_F_NOTIFY;
2967	if (IPCB(skb)->flags & IPSKB_DOREDIRECT)
2968	r->rtm_flags |= RTCF_DOREDIRECT;
2969
2970	if (nla_put_in_addr(skb, attrtype: RTA_DST, addr: dst))
2971	goto nla_put_failure;
2972	if (src) {
2973	r->rtm_src_len = 32;
2974	if (nla_put_in_addr(skb, attrtype: RTA_SRC, addr: src))
2975	goto nla_put_failure;
2976	}
2977	if (rt->dst.dev &&
2978	nla_put_u32(skb, attrtype: RTA_OIF, value: rt->dst.dev->ifindex))
2979	goto nla_put_failure;
2980	if (rt->dst.lwtstate &&
2981	lwtunnel_fill_encap(skb, lwtstate: rt->dst.lwtstate, encap_attr: RTA_ENCAP, encap_type_attr: RTA_ENCAP_TYPE) < 0)
2982	goto nla_put_failure;
2983	#ifdef CONFIG_IP_ROUTE_CLASSID
2984	if (rt->dst.tclassid &&
2985	nla_put_u32(skb, attrtype: RTA_FLOW, value: rt->dst.tclassid))
2986	goto nla_put_failure;
2987	#endif
2988	if (fl4 && !rt_is_input_route(rt) &&
2989	fl4->saddr != src) {
2990	if (nla_put_in_addr(skb, attrtype: RTA_PREFSRC, addr: fl4->saddr))
2991	goto nla_put_failure;
2992	}
2993	if (rt->rt_uses_gateway) {
2994	if (rt->rt_gw_family == AF_INET &&
2995	nla_put_in_addr(skb, attrtype: RTA_GATEWAY, addr: rt->rt_gw4)) {
2996	goto nla_put_failure;
2997	} else if (rt->rt_gw_family == AF_INET6) {
2998	int alen = sizeof(struct in6_addr);
2999	struct nlattr *nla;
3000	struct rtvia *via;
3001
3002	nla = nla_reserve(skb, attrtype: RTA_VIA, attrlen: alen + 2);
3003	if (!nla)
3004	goto nla_put_failure;
3005
3006	via = nla_data(nla);
3007	via->rtvia_family = AF_INET6;
3008	memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
3009	}
3010	}
3011
3012	expires = rt->dst.expires;
3013	if (expires) {
3014	unsigned long now = jiffies;
3015
3016	if (time_before(now, expires))
3017	expires -= now;
3018	else
3019	expires = 0;
3020	}
3021
3022	memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));
3023	if (rt->rt_pmtu && expires)
3024	metrics[RTAX_MTU - 1] = rt->rt_pmtu;
3025	if (rt->rt_mtu_locked && expires)
3026	metrics[RTAX_LOCK - 1] |= BIT(RTAX_MTU);
3027	if (rtnetlink_put_metrics(skb, metrics) < 0)
3028	goto nla_put_failure;
3029
3030	if (fl4) {
3031	if (fl4->flowi4_mark &&
3032	nla_put_u32(skb, attrtype: RTA_MARK, value: fl4->flowi4_mark))
3033	goto nla_put_failure;
3034
3035	if (!uid_eq(left: fl4->flowi4_uid, INVALID_UID) &&
3036	nla_put_u32(skb, attrtype: RTA_UID,
3037	value: from_kuid_munged(current_user_ns(),
3038	uid: fl4->flowi4_uid)))
3039	goto nla_put_failure;
3040
3041	if (rt_is_input_route(rt)) {
3042	#ifdef CONFIG_IP_MROUTE
3043	if (ipv4_is_multicast(addr: dst) &&
3044	!ipv4_is_local_multicast(addr: dst) &&
3045	IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) {
3046	int err = ipmr_get_route(net, skb,
3047	saddr: fl4->saddr, daddr: fl4->daddr,
3048	rtm: r, portid);
3049
3050	if (err <= 0) {
3051	if (err == 0)
3052	return 0;
3053	goto nla_put_failure;
3054	}
3055	} else
3056	#endif
3057	if (nla_put_u32(skb, attrtype: RTA_IIF, value: fl4->flowi4_iif))
3058	goto nla_put_failure;
3059	}
3060	}
3061
3062	error = rt->dst.error;
3063
3064	if (rtnl_put_cacheinfo(skb, dst: &rt->dst, id: 0, expires, error) < 0)
3065	goto nla_put_failure;
3066
3067	nlmsg_end(skb, nlh);
3068	return 0;
3069
3070	nla_put_failure:
3071	nlmsg_cancel(skb, nlh);
3072	return -EMSGSIZE;
3073	}
3074
3075	static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
3076	struct netlink_callback *cb, u32 table_id,
3077	struct fnhe_hash_bucket *bucket, int genid,
3078	int *fa_index, int fa_start, unsigned int flags)
3079	{
3080	int i;
3081
3082	for (i = 0; i < FNHE_HASH_SIZE; i++) {
3083	struct fib_nh_exception *fnhe;
3084
3085	for (fnhe = rcu_dereference(bucket[i].chain); fnhe;
3086	fnhe = rcu_dereference(fnhe->fnhe_next)) {
3087	struct rtable *rt;
3088	int err;
3089
3090	if (*fa_index < fa_start)
3091	goto next;
3092
3093	if (fnhe->fnhe_genid != genid)
3094	goto next;
3095
3096	if (fnhe->fnhe_expires &&
3097	time_after(jiffies, fnhe->fnhe_expires))
3098	goto next;
3099
3100	rt = rcu_dereference(fnhe->fnhe_rth_input);
3101	if (!rt)
3102	rt = rcu_dereference(fnhe->fnhe_rth_output);
3103	if (!rt)
3104	goto next;
3105
3106	err = rt_fill_info(net, dst: fnhe->fnhe_daddr, src: 0, rt,
3107	table_id, dscp: 0, NULL, skb,
3108	NETLINK_CB(cb->skb).portid,
3109	seq: cb->nlh->nlmsg_seq, flags);
3110	if (err)
3111	return err;
3112	next:
3113	(*fa_index)++;
3114	}
3115	}
3116
3117	return 0;
3118	}
3119
3120	int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
3121	u32 table_id, struct fib_info *fi,
3122	int *fa_index, int fa_start, unsigned int flags)
3123	{
3124	struct net *net = sock_net(sk: cb->skb->sk);
3125	int nhsel, genid = fnhe_genid(net);
3126
3127	for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
3128	struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
3129	struct fnhe_hash_bucket *bucket;
3130	int err;
3131
3132	if (nhc->nhc_flags & RTNH_F_DEAD)
3133	continue;
3134
3135	rcu_read_lock();
3136	bucket = rcu_dereference(nhc->nhc_exceptions);
3137	err = 0;
3138	if (bucket)
3139	err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
3140	genid, fa_index, fa_start,
3141	flags);
3142	rcu_read_unlock();
3143	if (err)
3144	return err;
3145	}
3146
3147	return 0;
3148	}
3149
3150	static struct sk_buff *inet_rtm_getroute_build_skb(__be32 src, __be32 dst,
3151	u8 ip_proto, __be16 sport,
3152	__be16 dport)
3153	{
3154	struct sk_buff *skb;
3155	struct iphdr *iph;
3156
3157	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
3158	if (!skb)
3159	return NULL;
3160
3161	/* Reserve room for dummy headers, this skb can pass
3162	* through good chunk of routing engine.
3163	*/
3164	skb_reset_mac_header(skb);
3165	skb_reset_network_header(skb);
3166	skb->protocol = htons(ETH_P_IP);
3167	iph = skb_put(skb, len: sizeof(struct iphdr));
3168	iph->protocol = ip_proto;
3169	iph->saddr = src;
3170	iph->daddr = dst;
3171	iph->version = 0x4;
3172	iph->frag_off = 0;
3173	iph->ihl = 0x5;
3174	skb_set_transport_header(skb, offset: skb->len);
3175
3176	switch (iph->protocol) {
3177	case IPPROTO_UDP: {
3178	struct udphdr *udph;
3179
3180	udph = skb_put_zero(skb, len: sizeof(struct udphdr));
3181	udph->source = sport;
3182	udph->dest = dport;
3183	udph->len = htons(sizeof(struct udphdr));
3184	udph->check = 0;
3185	break;
3186	}
3187	case IPPROTO_TCP: {
3188	struct tcphdr *tcph;
3189
3190	tcph = skb_put_zero(skb, len: sizeof(struct tcphdr));
3191	tcph->source = sport;
3192	tcph->dest = dport;
3193	tcph->doff = sizeof(struct tcphdr) / 4;
3194	tcph->rst = 1;
3195	tcph->check = ~tcp_v4_check(len: sizeof(struct tcphdr),
3196	saddr: src, daddr: dst, base: 0);
3197	break;
3198	}
3199	case IPPROTO_ICMP: {
3200	struct icmphdr *icmph;
3201
3202	icmph = skb_put_zero(skb, len: sizeof(struct icmphdr));
3203	icmph->type = ICMP_ECHO;
3204	icmph->code = 0;
3205	}
3206	}
3207
3208	return skb;
3209	}
3210
3211	static int inet_rtm_valid_getroute_req(struct sk_buff *skb,
3212	const struct nlmsghdr *nlh,
3213	struct nlattr **tb,
3214	struct netlink_ext_ack *extack)
3215	{
3216	struct rtmsg *rtm;
3217	int i, err;
3218
3219	rtm = nlmsg_payload(nlh, len: sizeof(*rtm));
3220	if (!rtm) {
3221	NL_SET_ERR_MSG(extack,
3222	"ipv4: Invalid header for route get request");
3223	return -EINVAL;
3224	}
3225
3226	if (!netlink_strict_get_check(skb))
3227	return nlmsg_parse_deprecated(nlh, hdrlen: sizeof(*rtm), tb, RTA_MAX,
3228	policy: rtm_ipv4_policy, extack);
3229
3230	if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
3231	(rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
3232	rtm->rtm_table || rtm->rtm_protocol ||
3233	rtm->rtm_scope || rtm->rtm_type) {
3234	NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for route get request");
3235	return -EINVAL;
3236	}
3237
3238	if (rtm->rtm_flags & ~(RTM_F_NOTIFY |
3239	RTM_F_LOOKUP_TABLE |
3240	RTM_F_FIB_MATCH)) {
3241	NL_SET_ERR_MSG(extack, "ipv4: Unsupported rtm_flags for route get request");
3242	return -EINVAL;
3243	}
3244
3245	err = nlmsg_parse_deprecated_strict(nlh, hdrlen: sizeof(*rtm), tb, RTA_MAX,
3246	policy: rtm_ipv4_policy, extack);
3247	if (err)
3248	return err;
3249
3250	if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
3251	(tb[RTA_DST] && !rtm->rtm_dst_len)) {
3252	NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
3253	return -EINVAL;
3254	}
3255
3256	for (i = 0; i <= RTA_MAX; i++) {
3257	if (!tb[i])
3258	continue;
3259
3260	switch (i) {
3261	case RTA_IIF:
3262	case RTA_OIF:
3263	case RTA_SRC:
3264	case RTA_DST:
3265	case RTA_IP_PROTO:
3266	case RTA_SPORT:
3267	case RTA_DPORT:
3268	case RTA_MARK:
3269	case RTA_UID:
3270	break;
3271	default:
3272	NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in route get request");
3273	return -EINVAL;
3274	}
3275	}
3276
3277	return 0;
3278	}
3279
3280	static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
3281	struct netlink_ext_ack *extack)
3282	{
3283	struct net *net = sock_net(sk: in_skb->sk);
3284	struct nlattr *tb[RTA_MAX+1];
3285	u32 table_id = RT_TABLE_MAIN;
3286	__be16 sport = 0, dport = 0;
3287	struct fib_result res = {};
3288	u8 ip_proto = IPPROTO_UDP;
3289	struct rtable *rt = NULL;
3290	struct sk_buff *skb;
3291	struct rtmsg *rtm;
3292	struct flowi4 fl4 = {};
3293	__be32 dst = 0;
3294	__be32 src = 0;
3295	dscp_t dscp;
3296	kuid_t uid;
3297	u32 iif;
3298	int err;
3299	int mark;
3300
3301	err = inet_rtm_valid_getroute_req(skb: in_skb, nlh, tb, extack);
3302	if (err < 0)
3303	return err;
3304
3305	rtm = nlmsg_data(nlh);
3306	src = nla_get_in_addr_default(nla: tb[RTA_SRC], defvalue: 0);
3307	dst = nla_get_in_addr_default(nla: tb[RTA_DST], defvalue: 0);
3308	iif = nla_get_u32_default(nla: tb[RTA_IIF], defvalue: 0);
3309	mark = nla_get_u32_default(nla: tb[RTA_MARK], defvalue: 0);
3310	dscp = inet_dsfield_to_dscp(dsfield: rtm->rtm_tos);
3311	if (tb[RTA_UID])
3312	uid = make_kuid(current_user_ns(), uid: nla_get_u32(nla: tb[RTA_UID]));
3313	else
3314	uid = (iif ? INVALID_UID : current_uid());
3315
3316	if (tb[RTA_IP_PROTO]) {
3317	err = rtm_getroute_parse_ip_proto(attr: tb[RTA_IP_PROTO],
3318	ip_proto: &ip_proto, AF_INET, extack);
3319	if (err)
3320	return err;
3321	}
3322
3323	if (tb[RTA_SPORT])
3324	sport = nla_get_be16(nla: tb[RTA_SPORT]);
3325
3326	if (tb[RTA_DPORT])
3327	dport = nla_get_be16(nla: tb[RTA_DPORT]);
3328
3329	skb = inet_rtm_getroute_build_skb(src, dst, ip_proto, sport, dport);
3330	if (!skb)
3331	return -ENOBUFS;
3332
3333	fl4.daddr = dst;
3334	fl4.saddr = src;
3335	fl4.flowi4_tos = inet_dscp_to_dsfield(dscp);
3336	fl4.flowi4_oif = nla_get_u32_default(nla: tb[RTA_OIF], defvalue: 0);
3337	fl4.flowi4_mark = mark;
3338	fl4.flowi4_uid = uid;
3339	if (sport)
3340	fl4.fl4_sport = sport;
3341	if (dport)
3342	fl4.fl4_dport = dport;
3343	fl4.flowi4_proto = ip_proto;
3344
3345	rcu_read_lock();
3346
3347	if (iif) {
3348	struct net_device *dev;
3349
3350	dev = dev_get_by_index_rcu(net, ifindex: iif);
3351	if (!dev) {
3352	err = -ENODEV;
3353	goto errout_rcu;
3354	}
3355
3356	fl4.flowi4_iif = iif; /* for rt_fill_info */
3357	skb->dev = dev;
3358	skb->mark = mark;
3359	err = ip_route_input_rcu(skb, daddr: dst, saddr: src, dscp, dev,
3360	res: &res) ? -EINVAL : 0;
3361
3362	rt = skb_rtable(skb);
3363	if (err == 0 && rt->dst.error)
3364	err = -rt->dst.error;
3365	} else {
3366	fl4.flowi4_iif = LOOPBACK_IFINDEX;
3367	skb->dev = net->loopback_dev;
3368	rt = ip_route_output_key_hash_rcu(net, fl4: &fl4, res: &res, skb);
3369	err = 0;
3370	if (IS_ERR(ptr: rt))
3371	err = PTR_ERR(ptr: rt);
3372	else
3373	skb_dst_set(skb, dst: &rt->dst);
3374	}
3375
3376	if (err)
3377	goto errout_rcu;
3378
3379	if (rtm->rtm_flags & RTM_F_NOTIFY)
3380	rt->rt_flags |= RTCF_NOTIFY;
3381
3382	if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
3383	table_id = res.table ? res.table->tb_id : 0;
3384
3385	/* reset skb for netlink reply msg */
3386	skb_trim(skb, len: 0);
3387	skb_reset_network_header(skb);
3388	skb_reset_transport_header(skb);
3389	skb_reset_mac_header(skb);
3390
3391	if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
3392	struct fib_rt_info fri;
3393
3394	if (!res.fi) {
3395	err = fib_props[res.type].error;
3396	if (!err)
3397	err = -EHOSTUNREACH;
3398	goto errout_rcu;
3399	}
3400	fri.fi = res.fi;
3401	fri.tb_id = table_id;
3402	fri.dst = res.prefix;
3403	fri.dst_len = res.prefixlen;
3404	fri.dscp = res.dscp;
3405	fri.type = rt->rt_type;
3406	fri.offload = 0;
3407	fri.trap = 0;
3408	fri.offload_failed = 0;
3409	if (res.fa_head) {
3410	struct fib_alias *fa;
3411
3412	hlist_for_each_entry_rcu(fa, res.fa_head, fa_list) {
3413	u8 slen = 32 - fri.dst_len;
3414
3415	if (fa->fa_slen == slen &&
3416	fa->tb_id == fri.tb_id &&
3417	fa->fa_dscp == fri.dscp &&
3418	fa->fa_info == res.fi &&
3419	fa->fa_type == fri.type) {
3420	fri.offload = READ_ONCE(fa->offload);
3421	fri.trap = READ_ONCE(fa->trap);
3422	fri.offload_failed =
3423	READ_ONCE(fa->offload_failed);
3424	break;
3425	}
3426	}
3427	}
3428	err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
3429	seq: nlh->nlmsg_seq, RTM_NEWROUTE, fri: &fri, flags: 0);
3430	} else {
3431	err = rt_fill_info(net, dst, src, rt, table_id, dscp: res.dscp, fl4: &fl4,
3432	skb, NETLINK_CB(in_skb).portid,
3433	seq: nlh->nlmsg_seq, flags: 0);
3434	}
3435	if (err < 0)
3436	goto errout_rcu;
3437
3438	rcu_read_unlock();
3439
3440	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
3441
3442	errout_free:
3443	return err;
3444	errout_rcu:
3445	rcu_read_unlock();
3446	kfree_skb(skb);
3447	goto errout_free;
3448	}
3449
3450	void ip_rt_multicast_event(struct in_device *in_dev)
3451	{
3452	rt_cache_flush(net: dev_net(dev: in_dev->dev));
3453	}
3454
3455	#ifdef CONFIG_SYSCTL
3456	static int ip_rt_gc_interval __read_mostly = 60 * HZ;
3457	static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
3458	static int ip_rt_gc_elasticity __read_mostly = 8;
3459	static int ip_min_valid_pmtu __read_mostly = IPV4_MIN_MTU;
3460
3461	static int ipv4_sysctl_rtcache_flush(const struct ctl_table *__ctl, int write,
3462	void *buffer, size_t *lenp, loff_t *ppos)
3463	{
3464	struct net *net = (struct net *)__ctl->extra1;
3465
3466	if (write) {
3467	rt_cache_flush(net);
3468	fnhe_genid_bump(net);
3469	return 0;
3470	}
3471
3472	return -EINVAL;
3473	}
3474
3475	static struct ctl_table ipv4_route_table[] = {
3476	{
3477	.procname = "gc_thresh",
3478	.data = &ipv4_dst_ops.gc_thresh,
3479	.maxlen = sizeof(int),
3480	.mode = 0644,
3481	.proc_handler = proc_dointvec,
3482	},
3483	{
3484	.procname = "max_size",
3485	.data = &ip_rt_max_size,
3486	.maxlen = sizeof(int),
3487	.mode = 0644,
3488	.proc_handler = proc_dointvec,
3489	},
3490	{
3491	/* Deprecated. Use gc_min_interval_ms */
3492
3493	.procname = "gc_min_interval",
3494	.data = &ip_rt_gc_min_interval,
3495	.maxlen = sizeof(int),
3496	.mode = 0644,
3497	.proc_handler = proc_dointvec_jiffies,
3498	},
3499	{
3500	.procname = "gc_min_interval_ms",
3501	.data = &ip_rt_gc_min_interval,
3502	.maxlen = sizeof(int),
3503	.mode = 0644,
3504	.proc_handler = proc_dointvec_ms_jiffies,
3505	},
3506	{
3507	.procname = "gc_timeout",
3508	.data = &ip_rt_gc_timeout,
3509	.maxlen = sizeof(int),
3510	.mode = 0644,
3511	.proc_handler = proc_dointvec_jiffies,
3512	},
3513	{
3514	.procname = "gc_interval",
3515	.data = &ip_rt_gc_interval,
3516	.maxlen = sizeof(int),
3517	.mode = 0644,
3518	.proc_handler = proc_dointvec_jiffies,
3519	},
3520	{
3521	.procname = "redirect_load",
3522	.data = &ip_rt_redirect_load,
3523	.maxlen = sizeof(int),
3524	.mode = 0644,
3525	.proc_handler = proc_dointvec,
3526	},
3527	{
3528	.procname = "redirect_number",
3529	.data = &ip_rt_redirect_number,
3530	.maxlen = sizeof(int),
3531	.mode = 0644,
3532	.proc_handler = proc_dointvec,
3533	},
3534	{
3535	.procname = "redirect_silence",
3536	.data = &ip_rt_redirect_silence,
3537	.maxlen = sizeof(int),
3538	.mode = 0644,
3539	.proc_handler = proc_dointvec,
3540	},
3541	{
3542	.procname = "error_cost",
3543	.data = &ip_rt_error_cost,
3544	.maxlen = sizeof(int),
3545	.mode = 0644,
3546	.proc_handler = proc_dointvec,
3547	},
3548	{
3549	.procname = "error_burst",
3550	.data = &ip_rt_error_burst,
3551	.maxlen = sizeof(int),
3552	.mode = 0644,
3553	.proc_handler = proc_dointvec,
3554	},
3555	{
3556	.procname = "gc_elasticity",
3557	.data = &ip_rt_gc_elasticity,
3558	.maxlen = sizeof(int),
3559	.mode = 0644,
3560	.proc_handler = proc_dointvec,
3561	},
3562	};
3563
3564	static const char ipv4_route_flush_procname[] = "flush";
3565
3566	static struct ctl_table ipv4_route_netns_table[] = {
3567	{
3568	.procname = ipv4_route_flush_procname,
3569	.maxlen = sizeof(int),
3570	.mode = 0200,
3571	.proc_handler = ipv4_sysctl_rtcache_flush,
3572	},
3573	{
3574	.procname = "min_pmtu",
3575	.data = &init_net.ipv4.ip_rt_min_pmtu,
3576	.maxlen = sizeof(int),
3577	.mode = 0644,
3578	.proc_handler = proc_dointvec_minmax,
3579	.extra1 = &ip_min_valid_pmtu,
3580	},
3581	{
3582	.procname = "mtu_expires",
3583	.data = &init_net.ipv4.ip_rt_mtu_expires,
3584	.maxlen = sizeof(int),
3585	.mode = 0644,
3586	.proc_handler = proc_dointvec_jiffies,
3587	},
3588	{
3589	.procname = "min_adv_mss",
3590	.data = &init_net.ipv4.ip_rt_min_advmss,
3591	.maxlen = sizeof(int),
3592	.mode = 0644,
3593	.proc_handler = proc_dointvec,
3594	},
3595	};
3596
3597	static __net_init int sysctl_route_net_init(struct net *net)
3598	{
3599	struct ctl_table *tbl;
3600	size_t table_size = ARRAY_SIZE(ipv4_route_netns_table);
3601
3602	tbl = ipv4_route_netns_table;
3603	if (!net_eq(net1: net, net2: &init_net)) {
3604	int i;
3605
3606	tbl = kmemdup(tbl, sizeof(ipv4_route_netns_table), GFP_KERNEL);
3607	if (!tbl)
3608	goto err_dup;
3609
3610	/* Don't export non-whitelisted sysctls to unprivileged users */
3611	if (net->user_ns != &init_user_ns) {
3612	if (tbl[0].procname != ipv4_route_flush_procname)
3613	table_size = 0;
3614	}
3615
3616	/* Update the variables to point into the current struct net
3617	* except for the first element flush
3618	*/
3619	for (i = 1; i < table_size; i++)
3620	tbl[i].data += (void *)net - (void *)&init_net;
3621	}
3622	tbl[0].extra1 = net;
3623
3624	net->ipv4.route_hdr = register_net_sysctl_sz(net, path: "net/ipv4/route",
3625	table: tbl, table_size);
3626	if (!net->ipv4.route_hdr)
3627	goto err_reg;
3628	return 0;
3629
3630	err_reg:
3631	if (tbl != ipv4_route_netns_table)
3632	kfree(objp: tbl);
3633	err_dup:
3634	return -ENOMEM;
3635	}
3636
3637	static __net_exit void sysctl_route_net_exit(struct net *net)
3638	{
3639	const struct ctl_table *tbl;
3640
3641	tbl = net->ipv4.route_hdr->ctl_table_arg;
3642	unregister_net_sysctl_table(header: net->ipv4.route_hdr);
3643	BUG_ON(tbl == ipv4_route_netns_table);
3644	kfree(objp: tbl);
3645	}
3646
3647	static __net_initdata struct pernet_operations sysctl_route_ops = {
3648	.init = sysctl_route_net_init,
3649	.exit = sysctl_route_net_exit,
3650	};
3651	#endif
3652
3653	static __net_init int netns_ip_rt_init(struct net *net)
3654	{
3655	/* Set default value for namespaceified sysctls */
3656	net->ipv4.ip_rt_min_pmtu = DEFAULT_MIN_PMTU;
3657	net->ipv4.ip_rt_mtu_expires = DEFAULT_MTU_EXPIRES;
3658	net->ipv4.ip_rt_min_advmss = DEFAULT_MIN_ADVMSS;
3659	return 0;
3660	}
3661
3662	static struct pernet_operations __net_initdata ip_rt_ops = {
3663	.init = netns_ip_rt_init,
3664	};
3665
3666	static __net_init int rt_genid_init(struct net *net)
3667	{
3668	atomic_set(v: &net->ipv4.rt_genid, i: 0);
3669	atomic_set(v: &net->fnhe_genid, i: 0);
3670	atomic_set(v: &net->ipv4.dev_addr_genid, i: get_random_u32());
3671	return 0;
3672	}
3673
3674	static __net_initdata struct pernet_operations rt_genid_ops = {
3675	.init = rt_genid_init,
3676	};
3677
3678	static int __net_init ipv4_inetpeer_init(struct net *net)
3679	{
3680	struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
3681
3682	if (!bp)
3683	return -ENOMEM;
3684	inet_peer_base_init(bp);
3685	net->ipv4.peers = bp;
3686	return 0;
3687	}
3688
3689	static void __net_exit ipv4_inetpeer_exit(struct net *net)
3690	{
3691	struct inet_peer_base *bp = net->ipv4.peers;
3692
3693	net->ipv4.peers = NULL;
3694	inetpeer_invalidate_tree(bp);
3695	kfree(objp: bp);
3696	}
3697
3698	static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
3699	.init = ipv4_inetpeer_init,
3700	.exit = ipv4_inetpeer_exit,
3701	};
3702
3703	#ifdef CONFIG_IP_ROUTE_CLASSID
3704	struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
3705	#endif /* CONFIG_IP_ROUTE_CLASSID */
3706
3707	static const struct rtnl_msg_handler ip_rt_rtnl_msg_handlers[] __initconst = {
3708	{.protocol = PF_INET, .msgtype = RTM_GETROUTE,
3709	.doit = inet_rtm_getroute, .flags = RTNL_FLAG_DOIT_UNLOCKED},
3710	};
3711
3712	int __init ip_rt_init(void)
3713	{
3714	void *idents_hash;
3715	int cpu;
3716
3717	/* For modern hosts, this will use 2 MB of memory */
3718	idents_hash = alloc_large_system_hash(tablename: "IP idents",
3719	bucketsize: sizeof(*ip_idents) + sizeof(*ip_tstamps),
3720	numentries: 0,
3721	scale: 16, /* one bucket per 64 KB */
3722	HASH_ZERO,
3723	NULL,
3724	hash_mask: &ip_idents_mask,
3725	low_limit: 2048,
3726	high_limit: 256*1024);
3727
3728	ip_idents = idents_hash;
3729
3730	get_random_bytes(buf: ip_idents, len: (ip_idents_mask + 1) * sizeof(*ip_idents));
3731
3732	ip_tstamps = idents_hash + (ip_idents_mask + 1) * sizeof(*ip_idents);
3733
3734	for_each_possible_cpu(cpu) {
3735	struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);
3736
3737	INIT_LIST_HEAD(list: &ul->head);
3738	spin_lock_init(&ul->lock);
3739	}
3740	#ifdef CONFIG_IP_ROUTE_CLASSID
3741	ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct));
3742	if (!ip_rt_acct)
3743	panic(fmt: "IP: failed to allocate ip_rt_acct\n");
3744	#endif
3745
3746	ipv4_dst_ops.kmem_cachep = KMEM_CACHE(rtable,
3747	SLAB_HWCACHE_ALIGN | SLAB_PANIC);
3748
3749	ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
3750
3751	if (dst_entries_init(dst: &ipv4_dst_ops) < 0)
3752	panic(fmt: "IP: failed to allocate ipv4_dst_ops counter\n");
3753
3754	if (dst_entries_init(dst: &ipv4_dst_blackhole_ops) < 0)
3755	panic(fmt: "IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
3756
3757	ipv4_dst_ops.gc_thresh = ~0;
3758	ip_rt_max_size = INT_MAX;
3759
3760	devinet_init();
3761	ip_fib_init();
3762
3763	if (ip_rt_proc_init())
3764	pr_err("Unable to create route proc files\n");
3765	#ifdef CONFIG_XFRM
3766	xfrm_init();
3767	xfrm4_init();
3768	#endif
3769	rtnl_register_many(ip_rt_rtnl_msg_handlers);
3770
3771	#ifdef CONFIG_SYSCTL
3772	register_pernet_subsys(&sysctl_route_ops);
3773	#endif
3774	register_pernet_subsys(&ip_rt_ops);
3775	register_pernet_subsys(&rt_genid_ops);
3776	register_pernet_subsys(&ipv4_inetpeer_ops);
3777	return 0;
3778	}
3779
3780	#ifdef CONFIG_SYSCTL
3781	/*
3782	* We really need to sanitize the damn ipv4 init order, then all
3783	* this nonsense will go away.
3784	*/
3785	void __init ip_static_sysctl_init(void)
3786	{
3787	register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table);
3788	}
3789	#endif
3790