xref: /openbmc/linux/net/ipv4/fib_frontend.c (revision d2ba09c1)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		IPv4 Forwarding Information Base: FIB frontend.
7  *
8  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9  *
10  *		This program is free software; you can redistribute it and/or
11  *		modify it under the terms of the GNU General Public License
12  *		as published by the Free Software Foundation; either version
13  *		2 of the License, or (at your option) any later version.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/uaccess.h>
18 #include <linux/bitops.h>
19 #include <linux/capability.h>
20 #include <linux/types.h>
21 #include <linux/kernel.h>
22 #include <linux/mm.h>
23 #include <linux/string.h>
24 #include <linux/socket.h>
25 #include <linux/sockios.h>
26 #include <linux/errno.h>
27 #include <linux/in.h>
28 #include <linux/inet.h>
29 #include <linux/inetdevice.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_addr.h>
32 #include <linux/if_arp.h>
33 #include <linux/skbuff.h>
34 #include <linux/cache.h>
35 #include <linux/init.h>
36 #include <linux/list.h>
37 #include <linux/slab.h>
38 
39 #include <net/ip.h>
40 #include <net/protocol.h>
41 #include <net/route.h>
42 #include <net/tcp.h>
43 #include <net/sock.h>
44 #include <net/arp.h>
45 #include <net/ip_fib.h>
46 #include <net/rtnetlink.h>
47 #include <net/xfrm.h>
48 #include <net/l3mdev.h>
49 #include <net/lwtunnel.h>
50 #include <trace/events/fib.h>
51 
52 #ifndef CONFIG_IP_MULTIPLE_TABLES
53 
54 static int __net_init fib4_rules_init(struct net *net)
55 {
56 	struct fib_table *local_table, *main_table;
57 
58 	main_table  = fib_trie_table(RT_TABLE_MAIN, NULL);
59 	if (!main_table)
60 		return -ENOMEM;
61 
62 	local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
63 	if (!local_table)
64 		goto fail;
65 
66 	hlist_add_head_rcu(&local_table->tb_hlist,
67 				&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
68 	hlist_add_head_rcu(&main_table->tb_hlist,
69 				&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
70 	return 0;
71 
72 fail:
73 	fib_free_table(main_table);
74 	return -ENOMEM;
75 }
76 
77 static bool fib4_has_custom_rules(struct net *net)
78 {
79 	return false;
80 }
81 #else
82 
83 struct fib_table *fib_new_table(struct net *net, u32 id)
84 {
85 	struct fib_table *tb, *alias = NULL;
86 	unsigned int h;
87 
88 	if (id == 0)
89 		id = RT_TABLE_MAIN;
90 	tb = fib_get_table(net, id);
91 	if (tb)
92 		return tb;
93 
94 	if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
95 		alias = fib_new_table(net, RT_TABLE_MAIN);
96 
97 	tb = fib_trie_table(id, alias);
98 	if (!tb)
99 		return NULL;
100 
101 	switch (id) {
102 	case RT_TABLE_MAIN:
103 		rcu_assign_pointer(net->ipv4.fib_main, tb);
104 		break;
105 	case RT_TABLE_DEFAULT:
106 		rcu_assign_pointer(net->ipv4.fib_default, tb);
107 		break;
108 	default:
109 		break;
110 	}
111 
112 	h = id & (FIB_TABLE_HASHSZ - 1);
113 	hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
114 	return tb;
115 }
116 EXPORT_SYMBOL_GPL(fib_new_table);
117 
118 /* caller must hold either rtnl or rcu read lock */
119 struct fib_table *fib_get_table(struct net *net, u32 id)
120 {
121 	struct fib_table *tb;
122 	struct hlist_head *head;
123 	unsigned int h;
124 
125 	if (id == 0)
126 		id = RT_TABLE_MAIN;
127 	h = id & (FIB_TABLE_HASHSZ - 1);
128 
129 	head = &net->ipv4.fib_table_hash[h];
130 	hlist_for_each_entry_rcu(tb, head, tb_hlist) {
131 		if (tb->tb_id == id)
132 			return tb;
133 	}
134 	return NULL;
135 }
136 
137 static bool fib4_has_custom_rules(struct net *net)
138 {
139 	return net->ipv4.fib_has_custom_rules;
140 }
141 #endif /* CONFIG_IP_MULTIPLE_TABLES */
142 
143 static void fib_replace_table(struct net *net, struct fib_table *old,
144 			      struct fib_table *new)
145 {
146 #ifdef CONFIG_IP_MULTIPLE_TABLES
147 	switch (new->tb_id) {
148 	case RT_TABLE_MAIN:
149 		rcu_assign_pointer(net->ipv4.fib_main, new);
150 		break;
151 	case RT_TABLE_DEFAULT:
152 		rcu_assign_pointer(net->ipv4.fib_default, new);
153 		break;
154 	default:
155 		break;
156 	}
157 
158 #endif
159 	/* replace the old table in the hlist */
160 	hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
161 }
162 
163 int fib_unmerge(struct net *net)
164 {
165 	struct fib_table *old, *new, *main_table;
166 
167 	/* attempt to fetch local table if it has been allocated */
168 	old = fib_get_table(net, RT_TABLE_LOCAL);
169 	if (!old)
170 		return 0;
171 
172 	new = fib_trie_unmerge(old);
173 	if (!new)
174 		return -ENOMEM;
175 
176 	/* table is already unmerged */
177 	if (new == old)
178 		return 0;
179 
180 	/* replace merged table with clean table */
181 	fib_replace_table(net, old, new);
182 	fib_free_table(old);
183 
184 	/* attempt to fetch main table if it has been allocated */
185 	main_table = fib_get_table(net, RT_TABLE_MAIN);
186 	if (!main_table)
187 		return 0;
188 
189 	/* flush local entries from main table */
190 	fib_table_flush_external(main_table);
191 
192 	return 0;
193 }
194 
195 static void fib_flush(struct net *net)
196 {
197 	int flushed = 0;
198 	unsigned int h;
199 
200 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
201 		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
202 		struct hlist_node *tmp;
203 		struct fib_table *tb;
204 
205 		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
206 			flushed += fib_table_flush(net, tb);
207 	}
208 
209 	if (flushed)
210 		rt_cache_flush(net);
211 }
212 
213 /*
214  * Find address type as if only "dev" was present in the system. If
215  * on_dev is NULL then all interfaces are taken into consideration.
216  */
217 static inline unsigned int __inet_dev_addr_type(struct net *net,
218 						const struct net_device *dev,
219 						__be32 addr, u32 tb_id)
220 {
221 	struct flowi4		fl4 = { .daddr = addr };
222 	struct fib_result	res;
223 	unsigned int ret = RTN_BROADCAST;
224 	struct fib_table *table;
225 
226 	if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
227 		return RTN_BROADCAST;
228 	if (ipv4_is_multicast(addr))
229 		return RTN_MULTICAST;
230 
231 	rcu_read_lock();
232 
233 	table = fib_get_table(net, tb_id);
234 	if (table) {
235 		ret = RTN_UNICAST;
236 		if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
237 			if (!dev || dev == res.fi->fib_dev)
238 				ret = res.type;
239 		}
240 	}
241 
242 	rcu_read_unlock();
243 	return ret;
244 }
245 
246 unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
247 {
248 	return __inet_dev_addr_type(net, NULL, addr, tb_id);
249 }
250 EXPORT_SYMBOL(inet_addr_type_table);
251 
252 unsigned int inet_addr_type(struct net *net, __be32 addr)
253 {
254 	return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
255 }
256 EXPORT_SYMBOL(inet_addr_type);
257 
258 unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
259 				__be32 addr)
260 {
261 	u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
262 
263 	return __inet_dev_addr_type(net, dev, addr, rt_table);
264 }
265 EXPORT_SYMBOL(inet_dev_addr_type);
266 
267 /* inet_addr_type with dev == NULL but using the table from a dev
268  * if one is associated
269  */
270 unsigned int inet_addr_type_dev_table(struct net *net,
271 				      const struct net_device *dev,
272 				      __be32 addr)
273 {
274 	u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
275 
276 	return __inet_dev_addr_type(net, NULL, addr, rt_table);
277 }
278 EXPORT_SYMBOL(inet_addr_type_dev_table);
279 
280 __be32 fib_compute_spec_dst(struct sk_buff *skb)
281 {
282 	struct net_device *dev = skb->dev;
283 	struct in_device *in_dev;
284 	struct fib_result res;
285 	struct rtable *rt;
286 	struct net *net;
287 	int scope;
288 
289 	rt = skb_rtable(skb);
290 	if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
291 	    RTCF_LOCAL)
292 		return ip_hdr(skb)->daddr;
293 
294 	in_dev = __in_dev_get_rcu(dev);
295 	BUG_ON(!in_dev);
296 
297 	net = dev_net(dev);
298 
299 	scope = RT_SCOPE_UNIVERSE;
300 	if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
301 		struct flowi4 fl4 = {
302 			.flowi4_iif = LOOPBACK_IFINDEX,
303 			.daddr = ip_hdr(skb)->saddr,
304 			.flowi4_tos = RT_TOS(ip_hdr(skb)->tos),
305 			.flowi4_scope = scope,
306 			.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0,
307 		};
308 		if (!fib_lookup(net, &fl4, &res, 0))
309 			return FIB_RES_PREFSRC(net, res);
310 	} else {
311 		scope = RT_SCOPE_LINK;
312 	}
313 
314 	return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
315 }
316 
317 /* Given (packet source, input interface) and optional (dst, oif, tos):
318  * - (main) check, that source is valid i.e. not broadcast or our local
319  *   address.
320  * - figure out what "logical" interface this packet arrived
321  *   and calculate "specific destination" address.
322  * - check, that packet arrived from expected physical interface.
323  * called with rcu_read_lock()
324  */
325 static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
326 				 u8 tos, int oif, struct net_device *dev,
327 				 int rpf, struct in_device *idev, u32 *itag)
328 {
329 	struct net *net = dev_net(dev);
330 	struct flow_keys flkeys;
331 	int ret, no_addr;
332 	struct fib_result res;
333 	struct flowi4 fl4;
334 	bool dev_match;
335 
336 	fl4.flowi4_oif = 0;
337 	fl4.flowi4_iif = l3mdev_master_ifindex_rcu(dev);
338 	if (!fl4.flowi4_iif)
339 		fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
340 	fl4.daddr = src;
341 	fl4.saddr = dst;
342 	fl4.flowi4_tos = tos;
343 	fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
344 	fl4.flowi4_tun_key.tun_id = 0;
345 	fl4.flowi4_flags = 0;
346 	fl4.flowi4_uid = sock_net_uid(net, NULL);
347 
348 	no_addr = idev->ifa_list == NULL;
349 
350 	fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
351 	if (!fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys)) {
352 		fl4.flowi4_proto = 0;
353 		fl4.fl4_sport = 0;
354 		fl4.fl4_dport = 0;
355 	}
356 
357 	trace_fib_validate_source(dev, &fl4);
358 
359 	if (fib_lookup(net, &fl4, &res, 0))
360 		goto last_resort;
361 	if (res.type != RTN_UNICAST &&
362 	    (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
363 		goto e_inval;
364 	fib_combine_itag(itag, &res);
365 	dev_match = false;
366 
367 #ifdef CONFIG_IP_ROUTE_MULTIPATH
368 	for (ret = 0; ret < res.fi->fib_nhs; ret++) {
369 		struct fib_nh *nh = &res.fi->fib_nh[ret];
370 
371 		if (nh->nh_dev == dev) {
372 			dev_match = true;
373 			break;
374 		} else if (l3mdev_master_ifindex_rcu(nh->nh_dev) == dev->ifindex) {
375 			dev_match = true;
376 			break;
377 		}
378 	}
379 #else
380 	if (FIB_RES_DEV(res) == dev)
381 		dev_match = true;
382 #endif
383 	if (dev_match) {
384 		ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
385 		return ret;
386 	}
387 	if (no_addr)
388 		goto last_resort;
389 	if (rpf == 1)
390 		goto e_rpf;
391 	fl4.flowi4_oif = dev->ifindex;
392 
393 	ret = 0;
394 	if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
395 		if (res.type == RTN_UNICAST)
396 			ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
397 	}
398 	return ret;
399 
400 last_resort:
401 	if (rpf)
402 		goto e_rpf;
403 	*itag = 0;
404 	return 0;
405 
406 e_inval:
407 	return -EINVAL;
408 e_rpf:
409 	return -EXDEV;
410 }
411 
412 /* Ignore rp_filter for packets protected by IPsec. */
413 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
414 			u8 tos, int oif, struct net_device *dev,
415 			struct in_device *idev, u32 *itag)
416 {
417 	int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
418 	struct net *net = dev_net(dev);
419 
420 	if (!r && !fib_num_tclassid_users(net) &&
421 	    (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
422 		if (IN_DEV_ACCEPT_LOCAL(idev))
423 			goto ok;
424 		/* with custom local routes in place, checking local addresses
425 		 * only will be too optimistic, with custom rules, checking
426 		 * local addresses only can be too strict, e.g. due to vrf
427 		 */
428 		if (net->ipv4.fib_has_custom_local_routes ||
429 		    fib4_has_custom_rules(net))
430 			goto full_check;
431 		if (inet_lookup_ifaddr_rcu(net, src))
432 			return -EINVAL;
433 
434 ok:
435 		*itag = 0;
436 		return 0;
437 	}
438 
439 full_check:
440 	return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
441 }
442 
443 static inline __be32 sk_extract_addr(struct sockaddr *addr)
444 {
445 	return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
446 }
447 
448 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
449 {
450 	struct nlattr *nla;
451 
452 	nla = (struct nlattr *) ((char *) mx + len);
453 	nla->nla_type = type;
454 	nla->nla_len = nla_attr_size(4);
455 	*(u32 *) nla_data(nla) = value;
456 
457 	return len + nla_total_size(4);
458 }
459 
460 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
461 				 struct fib_config *cfg)
462 {
463 	__be32 addr;
464 	int plen;
465 
466 	memset(cfg, 0, sizeof(*cfg));
467 	cfg->fc_nlinfo.nl_net = net;
468 
469 	if (rt->rt_dst.sa_family != AF_INET)
470 		return -EAFNOSUPPORT;
471 
472 	/*
473 	 * Check mask for validity:
474 	 * a) it must be contiguous.
475 	 * b) destination must have all host bits clear.
476 	 * c) if application forgot to set correct family (AF_INET),
477 	 *    reject request unless it is absolutely clear i.e.
478 	 *    both family and mask are zero.
479 	 */
480 	plen = 32;
481 	addr = sk_extract_addr(&rt->rt_dst);
482 	if (!(rt->rt_flags & RTF_HOST)) {
483 		__be32 mask = sk_extract_addr(&rt->rt_genmask);
484 
485 		if (rt->rt_genmask.sa_family != AF_INET) {
486 			if (mask || rt->rt_genmask.sa_family)
487 				return -EAFNOSUPPORT;
488 		}
489 
490 		if (bad_mask(mask, addr))
491 			return -EINVAL;
492 
493 		plen = inet_mask_len(mask);
494 	}
495 
496 	cfg->fc_dst_len = plen;
497 	cfg->fc_dst = addr;
498 
499 	if (cmd != SIOCDELRT) {
500 		cfg->fc_nlflags = NLM_F_CREATE;
501 		cfg->fc_protocol = RTPROT_BOOT;
502 	}
503 
504 	if (rt->rt_metric)
505 		cfg->fc_priority = rt->rt_metric - 1;
506 
507 	if (rt->rt_flags & RTF_REJECT) {
508 		cfg->fc_scope = RT_SCOPE_HOST;
509 		cfg->fc_type = RTN_UNREACHABLE;
510 		return 0;
511 	}
512 
513 	cfg->fc_scope = RT_SCOPE_NOWHERE;
514 	cfg->fc_type = RTN_UNICAST;
515 
516 	if (rt->rt_dev) {
517 		char *colon;
518 		struct net_device *dev;
519 		char devname[IFNAMSIZ];
520 
521 		if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
522 			return -EFAULT;
523 
524 		devname[IFNAMSIZ-1] = 0;
525 		colon = strchr(devname, ':');
526 		if (colon)
527 			*colon = 0;
528 		dev = __dev_get_by_name(net, devname);
529 		if (!dev)
530 			return -ENODEV;
531 		cfg->fc_oif = dev->ifindex;
532 		cfg->fc_table = l3mdev_fib_table(dev);
533 		if (colon) {
534 			struct in_ifaddr *ifa;
535 			struct in_device *in_dev = __in_dev_get_rtnl(dev);
536 			if (!in_dev)
537 				return -ENODEV;
538 			*colon = ':';
539 			for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
540 				if (strcmp(ifa->ifa_label, devname) == 0)
541 					break;
542 			if (!ifa)
543 				return -ENODEV;
544 			cfg->fc_prefsrc = ifa->ifa_local;
545 		}
546 	}
547 
548 	addr = sk_extract_addr(&rt->rt_gateway);
549 	if (rt->rt_gateway.sa_family == AF_INET && addr) {
550 		unsigned int addr_type;
551 
552 		cfg->fc_gw = addr;
553 		addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
554 		if (rt->rt_flags & RTF_GATEWAY &&
555 		    addr_type == RTN_UNICAST)
556 			cfg->fc_scope = RT_SCOPE_UNIVERSE;
557 	}
558 
559 	if (cmd == SIOCDELRT)
560 		return 0;
561 
562 	if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
563 		return -EINVAL;
564 
565 	if (cfg->fc_scope == RT_SCOPE_NOWHERE)
566 		cfg->fc_scope = RT_SCOPE_LINK;
567 
568 	if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
569 		struct nlattr *mx;
570 		int len = 0;
571 
572 		mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
573 		if (!mx)
574 			return -ENOMEM;
575 
576 		if (rt->rt_flags & RTF_MTU)
577 			len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
578 
579 		if (rt->rt_flags & RTF_WINDOW)
580 			len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
581 
582 		if (rt->rt_flags & RTF_IRTT)
583 			len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
584 
585 		cfg->fc_mx = mx;
586 		cfg->fc_mx_len = len;
587 	}
588 
589 	return 0;
590 }
591 
592 /*
593  * Handle IP routing ioctl calls.
594  * These are used to manipulate the routing tables
595  */
596 int ip_rt_ioctl(struct net *net, unsigned int cmd, struct rtentry *rt)
597 {
598 	struct fib_config cfg;
599 	int err;
600 
601 	switch (cmd) {
602 	case SIOCADDRT:		/* Add a route */
603 	case SIOCDELRT:		/* Delete a route */
604 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
605 			return -EPERM;
606 
607 		rtnl_lock();
608 		err = rtentry_to_fib_config(net, cmd, rt, &cfg);
609 		if (err == 0) {
610 			struct fib_table *tb;
611 
612 			if (cmd == SIOCDELRT) {
613 				tb = fib_get_table(net, cfg.fc_table);
614 				if (tb)
615 					err = fib_table_delete(net, tb, &cfg,
616 							       NULL);
617 				else
618 					err = -ESRCH;
619 			} else {
620 				tb = fib_new_table(net, cfg.fc_table);
621 				if (tb)
622 					err = fib_table_insert(net, tb,
623 							       &cfg, NULL);
624 				else
625 					err = -ENOBUFS;
626 			}
627 
628 			/* allocated by rtentry_to_fib_config() */
629 			kfree(cfg.fc_mx);
630 		}
631 		rtnl_unlock();
632 		return err;
633 	}
634 	return -EINVAL;
635 }
636 
637 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
638 	[RTA_DST]		= { .type = NLA_U32 },
639 	[RTA_SRC]		= { .type = NLA_U32 },
640 	[RTA_IIF]		= { .type = NLA_U32 },
641 	[RTA_OIF]		= { .type = NLA_U32 },
642 	[RTA_GATEWAY]		= { .type = NLA_U32 },
643 	[RTA_PRIORITY]		= { .type = NLA_U32 },
644 	[RTA_PREFSRC]		= { .type = NLA_U32 },
645 	[RTA_METRICS]		= { .type = NLA_NESTED },
646 	[RTA_MULTIPATH]		= { .len = sizeof(struct rtnexthop) },
647 	[RTA_FLOW]		= { .type = NLA_U32 },
648 	[RTA_ENCAP_TYPE]	= { .type = NLA_U16 },
649 	[RTA_ENCAP]		= { .type = NLA_NESTED },
650 	[RTA_UID]		= { .type = NLA_U32 },
651 	[RTA_MARK]		= { .type = NLA_U32 },
652 };
653 
654 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
655 			     struct nlmsghdr *nlh, struct fib_config *cfg,
656 			     struct netlink_ext_ack *extack)
657 {
658 	struct nlattr *attr;
659 	int err, remaining;
660 	struct rtmsg *rtm;
661 
662 	err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy,
663 			     extack);
664 	if (err < 0)
665 		goto errout;
666 
667 	memset(cfg, 0, sizeof(*cfg));
668 
669 	rtm = nlmsg_data(nlh);
670 	cfg->fc_dst_len = rtm->rtm_dst_len;
671 	cfg->fc_tos = rtm->rtm_tos;
672 	cfg->fc_table = rtm->rtm_table;
673 	cfg->fc_protocol = rtm->rtm_protocol;
674 	cfg->fc_scope = rtm->rtm_scope;
675 	cfg->fc_type = rtm->rtm_type;
676 	cfg->fc_flags = rtm->rtm_flags;
677 	cfg->fc_nlflags = nlh->nlmsg_flags;
678 
679 	cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
680 	cfg->fc_nlinfo.nlh = nlh;
681 	cfg->fc_nlinfo.nl_net = net;
682 
683 	if (cfg->fc_type > RTN_MAX) {
684 		NL_SET_ERR_MSG(extack, "Invalid route type");
685 		err = -EINVAL;
686 		goto errout;
687 	}
688 
689 	nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
690 		switch (nla_type(attr)) {
691 		case RTA_DST:
692 			cfg->fc_dst = nla_get_be32(attr);
693 			break;
694 		case RTA_OIF:
695 			cfg->fc_oif = nla_get_u32(attr);
696 			break;
697 		case RTA_GATEWAY:
698 			cfg->fc_gw = nla_get_be32(attr);
699 			break;
700 		case RTA_PRIORITY:
701 			cfg->fc_priority = nla_get_u32(attr);
702 			break;
703 		case RTA_PREFSRC:
704 			cfg->fc_prefsrc = nla_get_be32(attr);
705 			break;
706 		case RTA_METRICS:
707 			cfg->fc_mx = nla_data(attr);
708 			cfg->fc_mx_len = nla_len(attr);
709 			break;
710 		case RTA_MULTIPATH:
711 			err = lwtunnel_valid_encap_type_attr(nla_data(attr),
712 							     nla_len(attr),
713 							     extack);
714 			if (err < 0)
715 				goto errout;
716 			cfg->fc_mp = nla_data(attr);
717 			cfg->fc_mp_len = nla_len(attr);
718 			break;
719 		case RTA_FLOW:
720 			cfg->fc_flow = nla_get_u32(attr);
721 			break;
722 		case RTA_TABLE:
723 			cfg->fc_table = nla_get_u32(attr);
724 			break;
725 		case RTA_ENCAP:
726 			cfg->fc_encap = attr;
727 			break;
728 		case RTA_ENCAP_TYPE:
729 			cfg->fc_encap_type = nla_get_u16(attr);
730 			err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
731 							extack);
732 			if (err < 0)
733 				goto errout;
734 			break;
735 		}
736 	}
737 
738 	return 0;
739 errout:
740 	return err;
741 }
742 
743 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
744 			     struct netlink_ext_ack *extack)
745 {
746 	struct net *net = sock_net(skb->sk);
747 	struct fib_config cfg;
748 	struct fib_table *tb;
749 	int err;
750 
751 	err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
752 	if (err < 0)
753 		goto errout;
754 
755 	tb = fib_get_table(net, cfg.fc_table);
756 	if (!tb) {
757 		NL_SET_ERR_MSG(extack, "FIB table does not exist");
758 		err = -ESRCH;
759 		goto errout;
760 	}
761 
762 	err = fib_table_delete(net, tb, &cfg, extack);
763 errout:
764 	return err;
765 }
766 
767 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
768 			     struct netlink_ext_ack *extack)
769 {
770 	struct net *net = sock_net(skb->sk);
771 	struct fib_config cfg;
772 	struct fib_table *tb;
773 	int err;
774 
775 	err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
776 	if (err < 0)
777 		goto errout;
778 
779 	tb = fib_new_table(net, cfg.fc_table);
780 	if (!tb) {
781 		err = -ENOBUFS;
782 		goto errout;
783 	}
784 
785 	err = fib_table_insert(net, tb, &cfg, extack);
786 	if (!err && cfg.fc_type == RTN_LOCAL)
787 		net->ipv4.fib_has_custom_local_routes = true;
788 errout:
789 	return err;
790 }
791 
792 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
793 {
794 	struct net *net = sock_net(skb->sk);
795 	unsigned int h, s_h;
796 	unsigned int e = 0, s_e;
797 	struct fib_table *tb;
798 	struct hlist_head *head;
799 	int dumped = 0, err;
800 
801 	if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
802 	    ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
803 		return skb->len;
804 
805 	s_h = cb->args[0];
806 	s_e = cb->args[1];
807 
808 	rcu_read_lock();
809 
810 	for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
811 		e = 0;
812 		head = &net->ipv4.fib_table_hash[h];
813 		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
814 			if (e < s_e)
815 				goto next;
816 			if (dumped)
817 				memset(&cb->args[2], 0, sizeof(cb->args) -
818 						 2 * sizeof(cb->args[0]));
819 			err = fib_table_dump(tb, skb, cb);
820 			if (err < 0) {
821 				if (likely(skb->len))
822 					goto out;
823 
824 				goto out_err;
825 			}
826 			dumped = 1;
827 next:
828 			e++;
829 		}
830 	}
831 out:
832 	err = skb->len;
833 out_err:
834 	rcu_read_unlock();
835 
836 	cb->args[1] = e;
837 	cb->args[0] = h;
838 
839 	return err;
840 }
841 
842 /* Prepare and feed intra-kernel routing request.
843  * Really, it should be netlink message, but :-( netlink
844  * can be not configured, so that we feed it directly
845  * to fib engine. It is legal, because all events occur
846  * only when netlink is already locked.
847  */
848 static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
849 {
850 	struct net *net = dev_net(ifa->ifa_dev->dev);
851 	u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
852 	struct fib_table *tb;
853 	struct fib_config cfg = {
854 		.fc_protocol = RTPROT_KERNEL,
855 		.fc_type = type,
856 		.fc_dst = dst,
857 		.fc_dst_len = dst_len,
858 		.fc_prefsrc = ifa->ifa_local,
859 		.fc_oif = ifa->ifa_dev->dev->ifindex,
860 		.fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
861 		.fc_nlinfo = {
862 			.nl_net = net,
863 		},
864 	};
865 
866 	if (!tb_id)
867 		tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
868 
869 	tb = fib_new_table(net, tb_id);
870 	if (!tb)
871 		return;
872 
873 	cfg.fc_table = tb->tb_id;
874 
875 	if (type != RTN_LOCAL)
876 		cfg.fc_scope = RT_SCOPE_LINK;
877 	else
878 		cfg.fc_scope = RT_SCOPE_HOST;
879 
880 	if (cmd == RTM_NEWROUTE)
881 		fib_table_insert(net, tb, &cfg, NULL);
882 	else
883 		fib_table_delete(net, tb, &cfg, NULL);
884 }
885 
886 void fib_add_ifaddr(struct in_ifaddr *ifa)
887 {
888 	struct in_device *in_dev = ifa->ifa_dev;
889 	struct net_device *dev = in_dev->dev;
890 	struct in_ifaddr *prim = ifa;
891 	__be32 mask = ifa->ifa_mask;
892 	__be32 addr = ifa->ifa_local;
893 	__be32 prefix = ifa->ifa_address & mask;
894 
895 	if (ifa->ifa_flags & IFA_F_SECONDARY) {
896 		prim = inet_ifa_byprefix(in_dev, prefix, mask);
897 		if (!prim) {
898 			pr_warn("%s: bug: prim == NULL\n", __func__);
899 			return;
900 		}
901 	}
902 
903 	fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
904 
905 	if (!(dev->flags & IFF_UP))
906 		return;
907 
908 	/* Add broadcast address, if it is explicitly assigned. */
909 	if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
910 		fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
911 
912 	if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
913 	    (prefix != addr || ifa->ifa_prefixlen < 32)) {
914 		if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
915 			fib_magic(RTM_NEWROUTE,
916 				  dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
917 				  prefix, ifa->ifa_prefixlen, prim);
918 
919 		/* Add network specific broadcasts, when it takes a sense */
920 		if (ifa->ifa_prefixlen < 31) {
921 			fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
922 			fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
923 				  32, prim);
924 		}
925 	}
926 }
927 
928 /* Delete primary or secondary address.
929  * Optionally, on secondary address promotion consider the addresses
930  * from subnet iprim as deleted, even if they are in device list.
931  * In this case the secondary ifa can be in device list.
932  */
933 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
934 {
935 	struct in_device *in_dev = ifa->ifa_dev;
936 	struct net_device *dev = in_dev->dev;
937 	struct in_ifaddr *ifa1;
938 	struct in_ifaddr *prim = ifa, *prim1 = NULL;
939 	__be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
940 	__be32 any = ifa->ifa_address & ifa->ifa_mask;
941 #define LOCAL_OK	1
942 #define BRD_OK		2
943 #define BRD0_OK		4
944 #define BRD1_OK		8
945 	unsigned int ok = 0;
946 	int subnet = 0;		/* Primary network */
947 	int gone = 1;		/* Address is missing */
948 	int same_prefsrc = 0;	/* Another primary with same IP */
949 
950 	if (ifa->ifa_flags & IFA_F_SECONDARY) {
951 		prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
952 		if (!prim) {
953 			/* if the device has been deleted, we don't perform
954 			 * address promotion
955 			 */
956 			if (!in_dev->dead)
957 				pr_warn("%s: bug: prim == NULL\n", __func__);
958 			return;
959 		}
960 		if (iprim && iprim != prim) {
961 			pr_warn("%s: bug: iprim != prim\n", __func__);
962 			return;
963 		}
964 	} else if (!ipv4_is_zeronet(any) &&
965 		   (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
966 		if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
967 			fib_magic(RTM_DELROUTE,
968 				  dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
969 				  any, ifa->ifa_prefixlen, prim);
970 		subnet = 1;
971 	}
972 
973 	if (in_dev->dead)
974 		goto no_promotions;
975 
976 	/* Deletion is more complicated than add.
977 	 * We should take care of not to delete too much :-)
978 	 *
979 	 * Scan address list to be sure that addresses are really gone.
980 	 */
981 
982 	for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
983 		if (ifa1 == ifa) {
984 			/* promotion, keep the IP */
985 			gone = 0;
986 			continue;
987 		}
988 		/* Ignore IFAs from our subnet */
989 		if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
990 		    inet_ifa_match(ifa1->ifa_address, iprim))
991 			continue;
992 
993 		/* Ignore ifa1 if it uses different primary IP (prefsrc) */
994 		if (ifa1->ifa_flags & IFA_F_SECONDARY) {
995 			/* Another address from our subnet? */
996 			if (ifa1->ifa_mask == prim->ifa_mask &&
997 			    inet_ifa_match(ifa1->ifa_address, prim))
998 				prim1 = prim;
999 			else {
1000 				/* We reached the secondaries, so
1001 				 * same_prefsrc should be determined.
1002 				 */
1003 				if (!same_prefsrc)
1004 					continue;
1005 				/* Search new prim1 if ifa1 is not
1006 				 * using the current prim1
1007 				 */
1008 				if (!prim1 ||
1009 				    ifa1->ifa_mask != prim1->ifa_mask ||
1010 				    !inet_ifa_match(ifa1->ifa_address, prim1))
1011 					prim1 = inet_ifa_byprefix(in_dev,
1012 							ifa1->ifa_address,
1013 							ifa1->ifa_mask);
1014 				if (!prim1)
1015 					continue;
1016 				if (prim1->ifa_local != prim->ifa_local)
1017 					continue;
1018 			}
1019 		} else {
1020 			if (prim->ifa_local != ifa1->ifa_local)
1021 				continue;
1022 			prim1 = ifa1;
1023 			if (prim != prim1)
1024 				same_prefsrc = 1;
1025 		}
1026 		if (ifa->ifa_local == ifa1->ifa_local)
1027 			ok |= LOCAL_OK;
1028 		if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
1029 			ok |= BRD_OK;
1030 		if (brd == ifa1->ifa_broadcast)
1031 			ok |= BRD1_OK;
1032 		if (any == ifa1->ifa_broadcast)
1033 			ok |= BRD0_OK;
1034 		/* primary has network specific broadcasts */
1035 		if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
1036 			__be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
1037 			__be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
1038 
1039 			if (!ipv4_is_zeronet(any1)) {
1040 				if (ifa->ifa_broadcast == brd1 ||
1041 				    ifa->ifa_broadcast == any1)
1042 					ok |= BRD_OK;
1043 				if (brd == brd1 || brd == any1)
1044 					ok |= BRD1_OK;
1045 				if (any == brd1 || any == any1)
1046 					ok |= BRD0_OK;
1047 			}
1048 		}
1049 	}
1050 
1051 no_promotions:
1052 	if (!(ok & BRD_OK))
1053 		fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
1054 	if (subnet && ifa->ifa_prefixlen < 31) {
1055 		if (!(ok & BRD1_OK))
1056 			fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
1057 		if (!(ok & BRD0_OK))
1058 			fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
1059 	}
1060 	if (!(ok & LOCAL_OK)) {
1061 		unsigned int addr_type;
1062 
1063 		fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
1064 
1065 		/* Check, that this local address finally disappeared. */
1066 		addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
1067 						     ifa->ifa_local);
1068 		if (gone && addr_type != RTN_LOCAL) {
1069 			/* And the last, but not the least thing.
1070 			 * We must flush stray FIB entries.
1071 			 *
1072 			 * First of all, we scan fib_info list searching
1073 			 * for stray nexthop entries, then ignite fib_flush.
1074 			 */
1075 			if (fib_sync_down_addr(dev, ifa->ifa_local))
1076 				fib_flush(dev_net(dev));
1077 		}
1078 	}
1079 #undef LOCAL_OK
1080 #undef BRD_OK
1081 #undef BRD0_OK
1082 #undef BRD1_OK
1083 }
1084 
1085 static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
1086 {
1087 
1088 	struct fib_result       res;
1089 	struct flowi4           fl4 = {
1090 		.flowi4_mark = frn->fl_mark,
1091 		.daddr = frn->fl_addr,
1092 		.flowi4_tos = frn->fl_tos,
1093 		.flowi4_scope = frn->fl_scope,
1094 	};
1095 	struct fib_table *tb;
1096 
1097 	rcu_read_lock();
1098 
1099 	tb = fib_get_table(net, frn->tb_id_in);
1100 
1101 	frn->err = -ENOENT;
1102 	if (tb) {
1103 		local_bh_disable();
1104 
1105 		frn->tb_id = tb->tb_id;
1106 		frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
1107 
1108 		if (!frn->err) {
1109 			frn->prefixlen = res.prefixlen;
1110 			frn->nh_sel = res.nh_sel;
1111 			frn->type = res.type;
1112 			frn->scope = res.scope;
1113 		}
1114 		local_bh_enable();
1115 	}
1116 
1117 	rcu_read_unlock();
1118 }
1119 
1120 static void nl_fib_input(struct sk_buff *skb)
1121 {
1122 	struct net *net;
1123 	struct fib_result_nl *frn;
1124 	struct nlmsghdr *nlh;
1125 	u32 portid;
1126 
1127 	net = sock_net(skb->sk);
1128 	nlh = nlmsg_hdr(skb);
1129 	if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
1130 	    skb->len < nlh->nlmsg_len ||
1131 	    nlmsg_len(nlh) < sizeof(*frn))
1132 		return;
1133 
1134 	skb = netlink_skb_clone(skb, GFP_KERNEL);
1135 	if (!skb)
1136 		return;
1137 	nlh = nlmsg_hdr(skb);
1138 
1139 	frn = (struct fib_result_nl *) nlmsg_data(nlh);
1140 	nl_fib_lookup(net, frn);
1141 
1142 	portid = NETLINK_CB(skb).portid;      /* netlink portid */
1143 	NETLINK_CB(skb).portid = 0;        /* from kernel */
1144 	NETLINK_CB(skb).dst_group = 0;  /* unicast */
1145 	netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
1146 }
1147 
1148 static int __net_init nl_fib_lookup_init(struct net *net)
1149 {
1150 	struct sock *sk;
1151 	struct netlink_kernel_cfg cfg = {
1152 		.input	= nl_fib_input,
1153 	};
1154 
1155 	sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
1156 	if (!sk)
1157 		return -EAFNOSUPPORT;
1158 	net->ipv4.fibnl = sk;
1159 	return 0;
1160 }
1161 
1162 static void nl_fib_lookup_exit(struct net *net)
1163 {
1164 	netlink_kernel_release(net->ipv4.fibnl);
1165 	net->ipv4.fibnl = NULL;
1166 }
1167 
1168 static void fib_disable_ip(struct net_device *dev, unsigned long event,
1169 			   bool force)
1170 {
1171 	if (fib_sync_down_dev(dev, event, force))
1172 		fib_flush(dev_net(dev));
1173 	else
1174 		rt_cache_flush(dev_net(dev));
1175 	arp_ifdown(dev);
1176 }
1177 
1178 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1179 {
1180 	struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1181 	struct net_device *dev = ifa->ifa_dev->dev;
1182 	struct net *net = dev_net(dev);
1183 
1184 	switch (event) {
1185 	case NETDEV_UP:
1186 		fib_add_ifaddr(ifa);
1187 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1188 		fib_sync_up(dev, RTNH_F_DEAD);
1189 #endif
1190 		atomic_inc(&net->ipv4.dev_addr_genid);
1191 		rt_cache_flush(dev_net(dev));
1192 		break;
1193 	case NETDEV_DOWN:
1194 		fib_del_ifaddr(ifa, NULL);
1195 		atomic_inc(&net->ipv4.dev_addr_genid);
1196 		if (!ifa->ifa_dev->ifa_list) {
1197 			/* Last address was deleted from this interface.
1198 			 * Disable IP.
1199 			 */
1200 			fib_disable_ip(dev, event, true);
1201 		} else {
1202 			rt_cache_flush(dev_net(dev));
1203 		}
1204 		break;
1205 	}
1206 	return NOTIFY_DONE;
1207 }
1208 
1209 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1210 {
1211 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1212 	struct netdev_notifier_changeupper_info *info;
1213 	struct in_device *in_dev;
1214 	struct net *net = dev_net(dev);
1215 	unsigned int flags;
1216 
1217 	if (event == NETDEV_UNREGISTER) {
1218 		fib_disable_ip(dev, event, true);
1219 		rt_flush_dev(dev);
1220 		return NOTIFY_DONE;
1221 	}
1222 
1223 	in_dev = __in_dev_get_rtnl(dev);
1224 	if (!in_dev)
1225 		return NOTIFY_DONE;
1226 
1227 	switch (event) {
1228 	case NETDEV_UP:
1229 		for_ifa(in_dev) {
1230 			fib_add_ifaddr(ifa);
1231 		} endfor_ifa(in_dev);
1232 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1233 		fib_sync_up(dev, RTNH_F_DEAD);
1234 #endif
1235 		atomic_inc(&net->ipv4.dev_addr_genid);
1236 		rt_cache_flush(net);
1237 		break;
1238 	case NETDEV_DOWN:
1239 		fib_disable_ip(dev, event, false);
1240 		break;
1241 	case NETDEV_CHANGE:
1242 		flags = dev_get_flags(dev);
1243 		if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1244 			fib_sync_up(dev, RTNH_F_LINKDOWN);
1245 		else
1246 			fib_sync_down_dev(dev, event, false);
1247 		/* fall through */
1248 	case NETDEV_CHANGEMTU:
1249 		rt_cache_flush(net);
1250 		break;
1251 	case NETDEV_CHANGEUPPER:
1252 		info = ptr;
1253 		/* flush all routes if dev is linked to or unlinked from
1254 		 * an L3 master device (e.g., VRF)
1255 		 */
1256 		if (info->upper_dev && netif_is_l3_master(info->upper_dev))
1257 			fib_disable_ip(dev, NETDEV_DOWN, true);
1258 		break;
1259 	}
1260 	return NOTIFY_DONE;
1261 }
1262 
1263 static struct notifier_block fib_inetaddr_notifier = {
1264 	.notifier_call = fib_inetaddr_event,
1265 };
1266 
1267 static struct notifier_block fib_netdev_notifier = {
1268 	.notifier_call = fib_netdev_event,
1269 };
1270 
1271 static int __net_init ip_fib_net_init(struct net *net)
1272 {
1273 	int err;
1274 	size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1275 
1276 	err = fib4_notifier_init(net);
1277 	if (err)
1278 		return err;
1279 
1280 	/* Avoid false sharing : Use at least a full cache line */
1281 	size = max_t(size_t, size, L1_CACHE_BYTES);
1282 
1283 	net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1284 	if (!net->ipv4.fib_table_hash) {
1285 		err = -ENOMEM;
1286 		goto err_table_hash_alloc;
1287 	}
1288 
1289 	err = fib4_rules_init(net);
1290 	if (err < 0)
1291 		goto err_rules_init;
1292 	return 0;
1293 
1294 err_rules_init:
1295 	kfree(net->ipv4.fib_table_hash);
1296 err_table_hash_alloc:
1297 	fib4_notifier_exit(net);
1298 	return err;
1299 }
1300 
1301 static void ip_fib_net_exit(struct net *net)
1302 {
1303 	int i;
1304 
1305 	rtnl_lock();
1306 #ifdef CONFIG_IP_MULTIPLE_TABLES
1307 	RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
1308 	RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
1309 #endif
1310 	/* Destroy the tables in reverse order to guarantee that the
1311 	 * local table, ID 255, is destroyed before the main table, ID
1312 	 * 254. This is necessary as the local table may contain
1313 	 * references to data contained in the main table.
1314 	 */
1315 	for (i = FIB_TABLE_HASHSZ - 1; i >= 0; i--) {
1316 		struct hlist_head *head = &net->ipv4.fib_table_hash[i];
1317 		struct hlist_node *tmp;
1318 		struct fib_table *tb;
1319 
1320 		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1321 			hlist_del(&tb->tb_hlist);
1322 			fib_table_flush(net, tb);
1323 			fib_free_table(tb);
1324 		}
1325 	}
1326 
1327 #ifdef CONFIG_IP_MULTIPLE_TABLES
1328 	fib4_rules_exit(net);
1329 #endif
1330 	rtnl_unlock();
1331 	kfree(net->ipv4.fib_table_hash);
1332 	fib4_notifier_exit(net);
1333 }
1334 
1335 static int __net_init fib_net_init(struct net *net)
1336 {
1337 	int error;
1338 
1339 #ifdef CONFIG_IP_ROUTE_CLASSID
1340 	net->ipv4.fib_num_tclassid_users = 0;
1341 #endif
1342 	error = ip_fib_net_init(net);
1343 	if (error < 0)
1344 		goto out;
1345 	error = nl_fib_lookup_init(net);
1346 	if (error < 0)
1347 		goto out_nlfl;
1348 	error = fib_proc_init(net);
1349 	if (error < 0)
1350 		goto out_proc;
1351 out:
1352 	return error;
1353 
1354 out_proc:
1355 	nl_fib_lookup_exit(net);
1356 out_nlfl:
1357 	ip_fib_net_exit(net);
1358 	goto out;
1359 }
1360 
1361 static void __net_exit fib_net_exit(struct net *net)
1362 {
1363 	fib_proc_exit(net);
1364 	nl_fib_lookup_exit(net);
1365 	ip_fib_net_exit(net);
1366 }
1367 
1368 static struct pernet_operations fib_net_ops = {
1369 	.init = fib_net_init,
1370 	.exit = fib_net_exit,
1371 };
1372 
1373 void __init ip_fib_init(void)
1374 {
1375 	fib_trie_init();
1376 
1377 	register_pernet_subsys(&fib_net_ops);
1378 
1379 	register_netdevice_notifier(&fib_netdev_notifier);
1380 	register_inetaddr_notifier(&fib_inetaddr_notifier);
1381 
1382 	rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
1383 	rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
1384 	rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
1385 }
1386