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