ipv4, fib: pass LOOPBACK_IFINDEX instead of 0 to flowi4_iif
[sfrench/cifs-2.6.git] / net / ipv4 / fib_frontend.c
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
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
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
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
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  */
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
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
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
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  */
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, accept_local;
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         accept_local = IN_DEV_ACCEPT_LOCAL(idev);
262         fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
263
264         net = dev_net(dev);
265         if (fib_lookup(net, &fl4, &res))
266                 goto last_resort;
267         if (res.type != RTN_UNICAST) {
268                 if (res.type != RTN_LOCAL || !accept_local)
269                         goto e_inval;
270         }
271         fib_combine_itag(itag, &res);
272         dev_match = false;
273
274 #ifdef CONFIG_IP_ROUTE_MULTIPATH
275         for (ret = 0; ret < res.fi->fib_nhs; ret++) {
276                 struct fib_nh *nh = &res.fi->fib_nh[ret];
277
278                 if (nh->nh_dev == dev) {
279                         dev_match = true;
280                         break;
281                 }
282         }
283 #else
284         if (FIB_RES_DEV(res) == dev)
285                 dev_match = true;
286 #endif
287         if (dev_match) {
288                 ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
289                 return ret;
290         }
291         if (no_addr)
292                 goto last_resort;
293         if (rpf == 1)
294                 goto e_rpf;
295         fl4.flowi4_oif = dev->ifindex;
296
297         ret = 0;
298         if (fib_lookup(net, &fl4, &res) == 0) {
299                 if (res.type == RTN_UNICAST)
300                         ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
301         }
302         return ret;
303
304 last_resort:
305         if (rpf)
306                 goto e_rpf;
307         *itag = 0;
308         return 0;
309
310 e_inval:
311         return -EINVAL;
312 e_rpf:
313         return -EXDEV;
314 }
315
316 /* Ignore rp_filter for packets protected by IPsec. */
317 int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
318                         u8 tos, int oif, struct net_device *dev,
319                         struct in_device *idev, u32 *itag)
320 {
321         int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
322
323         if (!r && !fib_num_tclassid_users(dev_net(dev)) &&
324             (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
325                 *itag = 0;
326                 return 0;
327         }
328         return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
329 }
330
331 static inline __be32 sk_extract_addr(struct sockaddr *addr)
332 {
333         return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
334 }
335
336 static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
337 {
338         struct nlattr *nla;
339
340         nla = (struct nlattr *) ((char *) mx + len);
341         nla->nla_type = type;
342         nla->nla_len = nla_attr_size(4);
343         *(u32 *) nla_data(nla) = value;
344
345         return len + nla_total_size(4);
346 }
347
348 static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
349                                  struct fib_config *cfg)
350 {
351         __be32 addr;
352         int plen;
353
354         memset(cfg, 0, sizeof(*cfg));
355         cfg->fc_nlinfo.nl_net = net;
356
357         if (rt->rt_dst.sa_family != AF_INET)
358                 return -EAFNOSUPPORT;
359
360         /*
361          * Check mask for validity:
362          * a) it must be contiguous.
363          * b) destination must have all host bits clear.
364          * c) if application forgot to set correct family (AF_INET),
365          *    reject request unless it is absolutely clear i.e.
366          *    both family and mask are zero.
367          */
368         plen = 32;
369         addr = sk_extract_addr(&rt->rt_dst);
370         if (!(rt->rt_flags & RTF_HOST)) {
371                 __be32 mask = sk_extract_addr(&rt->rt_genmask);
372
373                 if (rt->rt_genmask.sa_family != AF_INET) {
374                         if (mask || rt->rt_genmask.sa_family)
375                                 return -EAFNOSUPPORT;
376                 }
377
378                 if (bad_mask(mask, addr))
379                         return -EINVAL;
380
381                 plen = inet_mask_len(mask);
382         }
383
384         cfg->fc_dst_len = plen;
385         cfg->fc_dst = addr;
386
387         if (cmd != SIOCDELRT) {
388                 cfg->fc_nlflags = NLM_F_CREATE;
389                 cfg->fc_protocol = RTPROT_BOOT;
390         }
391
392         if (rt->rt_metric)
393                 cfg->fc_priority = rt->rt_metric - 1;
394
395         if (rt->rt_flags & RTF_REJECT) {
396                 cfg->fc_scope = RT_SCOPE_HOST;
397                 cfg->fc_type = RTN_UNREACHABLE;
398                 return 0;
399         }
400
401         cfg->fc_scope = RT_SCOPE_NOWHERE;
402         cfg->fc_type = RTN_UNICAST;
403
404         if (rt->rt_dev) {
405                 char *colon;
406                 struct net_device *dev;
407                 char devname[IFNAMSIZ];
408
409                 if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
410                         return -EFAULT;
411
412                 devname[IFNAMSIZ-1] = 0;
413                 colon = strchr(devname, ':');
414                 if (colon)
415                         *colon = 0;
416                 dev = __dev_get_by_name(net, devname);
417                 if (!dev)
418                         return -ENODEV;
419                 cfg->fc_oif = dev->ifindex;
420                 if (colon) {
421                         struct in_ifaddr *ifa;
422                         struct in_device *in_dev = __in_dev_get_rtnl(dev);
423                         if (!in_dev)
424                                 return -ENODEV;
425                         *colon = ':';
426                         for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
427                                 if (strcmp(ifa->ifa_label, devname) == 0)
428                                         break;
429                         if (ifa == NULL)
430                                 return -ENODEV;
431                         cfg->fc_prefsrc = ifa->ifa_local;
432                 }
433         }
434
435         addr = sk_extract_addr(&rt->rt_gateway);
436         if (rt->rt_gateway.sa_family == AF_INET && addr) {
437                 cfg->fc_gw = addr;
438                 if (rt->rt_flags & RTF_GATEWAY &&
439                     inet_addr_type(net, addr) == RTN_UNICAST)
440                         cfg->fc_scope = RT_SCOPE_UNIVERSE;
441         }
442
443         if (cmd == SIOCDELRT)
444                 return 0;
445
446         if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
447                 return -EINVAL;
448
449         if (cfg->fc_scope == RT_SCOPE_NOWHERE)
450                 cfg->fc_scope = RT_SCOPE_LINK;
451
452         if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
453                 struct nlattr *mx;
454                 int len = 0;
455
456                 mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
457                 if (mx == NULL)
458                         return -ENOMEM;
459
460                 if (rt->rt_flags & RTF_MTU)
461                         len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
462
463                 if (rt->rt_flags & RTF_WINDOW)
464                         len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
465
466                 if (rt->rt_flags & RTF_IRTT)
467                         len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
468
469                 cfg->fc_mx = mx;
470                 cfg->fc_mx_len = len;
471         }
472
473         return 0;
474 }
475
476 /*
477  * Handle IP routing ioctl calls.
478  * These are used to manipulate the routing tables
479  */
480 int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
481 {
482         struct fib_config cfg;
483         struct rtentry rt;
484         int err;
485
486         switch (cmd) {
487         case SIOCADDRT:         /* Add a route */
488         case SIOCDELRT:         /* Delete a route */
489                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
490                         return -EPERM;
491
492                 if (copy_from_user(&rt, arg, sizeof(rt)))
493                         return -EFAULT;
494
495                 rtnl_lock();
496                 err = rtentry_to_fib_config(net, cmd, &rt, &cfg);
497                 if (err == 0) {
498                         struct fib_table *tb;
499
500                         if (cmd == SIOCDELRT) {
501                                 tb = fib_get_table(net, cfg.fc_table);
502                                 if (tb)
503                                         err = fib_table_delete(tb, &cfg);
504                                 else
505                                         err = -ESRCH;
506                         } else {
507                                 tb = fib_new_table(net, cfg.fc_table);
508                                 if (tb)
509                                         err = fib_table_insert(tb, &cfg);
510                                 else
511                                         err = -ENOBUFS;
512                         }
513
514                         /* allocated by rtentry_to_fib_config() */
515                         kfree(cfg.fc_mx);
516                 }
517                 rtnl_unlock();
518                 return err;
519         }
520         return -EINVAL;
521 }
522
523 const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
524         [RTA_DST]               = { .type = NLA_U32 },
525         [RTA_SRC]               = { .type = NLA_U32 },
526         [RTA_IIF]               = { .type = NLA_U32 },
527         [RTA_OIF]               = { .type = NLA_U32 },
528         [RTA_GATEWAY]           = { .type = NLA_U32 },
529         [RTA_PRIORITY]          = { .type = NLA_U32 },
530         [RTA_PREFSRC]           = { .type = NLA_U32 },
531         [RTA_METRICS]           = { .type = NLA_NESTED },
532         [RTA_MULTIPATH]         = { .len = sizeof(struct rtnexthop) },
533         [RTA_FLOW]              = { .type = NLA_U32 },
534 };
535
536 static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
537                              struct nlmsghdr *nlh, struct fib_config *cfg)
538 {
539         struct nlattr *attr;
540         int err, remaining;
541         struct rtmsg *rtm;
542
543         err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy);
544         if (err < 0)
545                 goto errout;
546
547         memset(cfg, 0, sizeof(*cfg));
548
549         rtm = nlmsg_data(nlh);
550         cfg->fc_dst_len = rtm->rtm_dst_len;
551         cfg->fc_tos = rtm->rtm_tos;
552         cfg->fc_table = rtm->rtm_table;
553         cfg->fc_protocol = rtm->rtm_protocol;
554         cfg->fc_scope = rtm->rtm_scope;
555         cfg->fc_type = rtm->rtm_type;
556         cfg->fc_flags = rtm->rtm_flags;
557         cfg->fc_nlflags = nlh->nlmsg_flags;
558
559         cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
560         cfg->fc_nlinfo.nlh = nlh;
561         cfg->fc_nlinfo.nl_net = net;
562
563         if (cfg->fc_type > RTN_MAX) {
564                 err = -EINVAL;
565                 goto errout;
566         }
567
568         nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
569                 switch (nla_type(attr)) {
570                 case RTA_DST:
571                         cfg->fc_dst = nla_get_be32(attr);
572                         break;
573                 case RTA_OIF:
574                         cfg->fc_oif = nla_get_u32(attr);
575                         break;
576                 case RTA_GATEWAY:
577                         cfg->fc_gw = nla_get_be32(attr);
578                         break;
579                 case RTA_PRIORITY:
580                         cfg->fc_priority = nla_get_u32(attr);
581                         break;
582                 case RTA_PREFSRC:
583                         cfg->fc_prefsrc = nla_get_be32(attr);
584                         break;
585                 case RTA_METRICS:
586                         cfg->fc_mx = nla_data(attr);
587                         cfg->fc_mx_len = nla_len(attr);
588                         break;
589                 case RTA_MULTIPATH:
590                         cfg->fc_mp = nla_data(attr);
591                         cfg->fc_mp_len = nla_len(attr);
592                         break;
593                 case RTA_FLOW:
594                         cfg->fc_flow = nla_get_u32(attr);
595                         break;
596                 case RTA_TABLE:
597                         cfg->fc_table = nla_get_u32(attr);
598                         break;
599                 }
600         }
601
602         return 0;
603 errout:
604         return err;
605 }
606
607 static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
608 {
609         struct net *net = sock_net(skb->sk);
610         struct fib_config cfg;
611         struct fib_table *tb;
612         int err;
613
614         err = rtm_to_fib_config(net, skb, nlh, &cfg);
615         if (err < 0)
616                 goto errout;
617
618         tb = fib_get_table(net, cfg.fc_table);
619         if (tb == NULL) {
620                 err = -ESRCH;
621                 goto errout;
622         }
623
624         err = fib_table_delete(tb, &cfg);
625 errout:
626         return err;
627 }
628
629 static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
630 {
631         struct net *net = sock_net(skb->sk);
632         struct fib_config cfg;
633         struct fib_table *tb;
634         int err;
635
636         err = rtm_to_fib_config(net, skb, nlh, &cfg);
637         if (err < 0)
638                 goto errout;
639
640         tb = fib_new_table(net, cfg.fc_table);
641         if (tb == NULL) {
642                 err = -ENOBUFS;
643                 goto errout;
644         }
645
646         err = fib_table_insert(tb, &cfg);
647 errout:
648         return err;
649 }
650
651 static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
652 {
653         struct net *net = sock_net(skb->sk);
654         unsigned int h, s_h;
655         unsigned int e = 0, s_e;
656         struct fib_table *tb;
657         struct hlist_head *head;
658         int dumped = 0;
659
660         if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
661             ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
662                 return skb->len;
663
664         s_h = cb->args[0];
665         s_e = cb->args[1];
666
667         for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
668                 e = 0;
669                 head = &net->ipv4.fib_table_hash[h];
670                 hlist_for_each_entry(tb, head, tb_hlist) {
671                         if (e < s_e)
672                                 goto next;
673                         if (dumped)
674                                 memset(&cb->args[2], 0, sizeof(cb->args) -
675                                                  2 * sizeof(cb->args[0]));
676                         if (fib_table_dump(tb, skb, cb) < 0)
677                                 goto out;
678                         dumped = 1;
679 next:
680                         e++;
681                 }
682         }
683 out:
684         cb->args[1] = e;
685         cb->args[0] = h;
686
687         return skb->len;
688 }
689
690 /* Prepare and feed intra-kernel routing request.
691  * Really, it should be netlink message, but :-( netlink
692  * can be not configured, so that we feed it directly
693  * to fib engine. It is legal, because all events occur
694  * only when netlink is already locked.
695  */
696 static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
697 {
698         struct net *net = dev_net(ifa->ifa_dev->dev);
699         struct fib_table *tb;
700         struct fib_config cfg = {
701                 .fc_protocol = RTPROT_KERNEL,
702                 .fc_type = type,
703                 .fc_dst = dst,
704                 .fc_dst_len = dst_len,
705                 .fc_prefsrc = ifa->ifa_local,
706                 .fc_oif = ifa->ifa_dev->dev->ifindex,
707                 .fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
708                 .fc_nlinfo = {
709                         .nl_net = net,
710                 },
711         };
712
713         if (type == RTN_UNICAST)
714                 tb = fib_new_table(net, RT_TABLE_MAIN);
715         else
716                 tb = fib_new_table(net, RT_TABLE_LOCAL);
717
718         if (tb == NULL)
719                 return;
720
721         cfg.fc_table = tb->tb_id;
722
723         if (type != RTN_LOCAL)
724                 cfg.fc_scope = RT_SCOPE_LINK;
725         else
726                 cfg.fc_scope = RT_SCOPE_HOST;
727
728         if (cmd == RTM_NEWROUTE)
729                 fib_table_insert(tb, &cfg);
730         else
731                 fib_table_delete(tb, &cfg);
732 }
733
734 void fib_add_ifaddr(struct in_ifaddr *ifa)
735 {
736         struct in_device *in_dev = ifa->ifa_dev;
737         struct net_device *dev = in_dev->dev;
738         struct in_ifaddr *prim = ifa;
739         __be32 mask = ifa->ifa_mask;
740         __be32 addr = ifa->ifa_local;
741         __be32 prefix = ifa->ifa_address & mask;
742
743         if (ifa->ifa_flags & IFA_F_SECONDARY) {
744                 prim = inet_ifa_byprefix(in_dev, prefix, mask);
745                 if (prim == NULL) {
746                         pr_warn("%s: bug: prim == NULL\n", __func__);
747                         return;
748                 }
749         }
750
751         fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
752
753         if (!(dev->flags & IFF_UP))
754                 return;
755
756         /* Add broadcast address, if it is explicitly assigned. */
757         if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
758                 fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
759
760         if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
761             (prefix != addr || ifa->ifa_prefixlen < 32)) {
762                 fib_magic(RTM_NEWROUTE,
763                           dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
764                           prefix, ifa->ifa_prefixlen, prim);
765
766                 /* Add network specific broadcasts, when it takes a sense */
767                 if (ifa->ifa_prefixlen < 31) {
768                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
769                         fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
770                                   32, prim);
771                 }
772         }
773 }
774
775 /* Delete primary or secondary address.
776  * Optionally, on secondary address promotion consider the addresses
777  * from subnet iprim as deleted, even if they are in device list.
778  * In this case the secondary ifa can be in device list.
779  */
780 void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
781 {
782         struct in_device *in_dev = ifa->ifa_dev;
783         struct net_device *dev = in_dev->dev;
784         struct in_ifaddr *ifa1;
785         struct in_ifaddr *prim = ifa, *prim1 = NULL;
786         __be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
787         __be32 any = ifa->ifa_address & ifa->ifa_mask;
788 #define LOCAL_OK        1
789 #define BRD_OK          2
790 #define BRD0_OK         4
791 #define BRD1_OK         8
792         unsigned int ok = 0;
793         int subnet = 0;         /* Primary network */
794         int gone = 1;           /* Address is missing */
795         int same_prefsrc = 0;   /* Another primary with same IP */
796
797         if (ifa->ifa_flags & IFA_F_SECONDARY) {
798                 prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
799                 if (prim == NULL) {
800                         pr_warn("%s: bug: prim == NULL\n", __func__);
801                         return;
802                 }
803                 if (iprim && iprim != prim) {
804                         pr_warn("%s: bug: iprim != prim\n", __func__);
805                         return;
806                 }
807         } else if (!ipv4_is_zeronet(any) &&
808                    (any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
809                 fib_magic(RTM_DELROUTE,
810                           dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
811                           any, ifa->ifa_prefixlen, prim);
812                 subnet = 1;
813         }
814
815         /* Deletion is more complicated than add.
816          * We should take care of not to delete too much :-)
817          *
818          * Scan address list to be sure that addresses are really gone.
819          */
820
821         for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
822                 if (ifa1 == ifa) {
823                         /* promotion, keep the IP */
824                         gone = 0;
825                         continue;
826                 }
827                 /* Ignore IFAs from our subnet */
828                 if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
829                     inet_ifa_match(ifa1->ifa_address, iprim))
830                         continue;
831
832                 /* Ignore ifa1 if it uses different primary IP (prefsrc) */
833                 if (ifa1->ifa_flags & IFA_F_SECONDARY) {
834                         /* Another address from our subnet? */
835                         if (ifa1->ifa_mask == prim->ifa_mask &&
836                             inet_ifa_match(ifa1->ifa_address, prim))
837                                 prim1 = prim;
838                         else {
839                                 /* We reached the secondaries, so
840                                  * same_prefsrc should be determined.
841                                  */
842                                 if (!same_prefsrc)
843                                         continue;
844                                 /* Search new prim1 if ifa1 is not
845                                  * using the current prim1
846                                  */
847                                 if (!prim1 ||
848                                     ifa1->ifa_mask != prim1->ifa_mask ||
849                                     !inet_ifa_match(ifa1->ifa_address, prim1))
850                                         prim1 = inet_ifa_byprefix(in_dev,
851                                                         ifa1->ifa_address,
852                                                         ifa1->ifa_mask);
853                                 if (!prim1)
854                                         continue;
855                                 if (prim1->ifa_local != prim->ifa_local)
856                                         continue;
857                         }
858                 } else {
859                         if (prim->ifa_local != ifa1->ifa_local)
860                                 continue;
861                         prim1 = ifa1;
862                         if (prim != prim1)
863                                 same_prefsrc = 1;
864                 }
865                 if (ifa->ifa_local == ifa1->ifa_local)
866                         ok |= LOCAL_OK;
867                 if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
868                         ok |= BRD_OK;
869                 if (brd == ifa1->ifa_broadcast)
870                         ok |= BRD1_OK;
871                 if (any == ifa1->ifa_broadcast)
872                         ok |= BRD0_OK;
873                 /* primary has network specific broadcasts */
874                 if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
875                         __be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
876                         __be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
877
878                         if (!ipv4_is_zeronet(any1)) {
879                                 if (ifa->ifa_broadcast == brd1 ||
880                                     ifa->ifa_broadcast == any1)
881                                         ok |= BRD_OK;
882                                 if (brd == brd1 || brd == any1)
883                                         ok |= BRD1_OK;
884                                 if (any == brd1 || any == any1)
885                                         ok |= BRD0_OK;
886                         }
887                 }
888         }
889
890         if (!(ok & BRD_OK))
891                 fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
892         if (subnet && ifa->ifa_prefixlen < 31) {
893                 if (!(ok & BRD1_OK))
894                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
895                 if (!(ok & BRD0_OK))
896                         fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
897         }
898         if (!(ok & LOCAL_OK)) {
899                 fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
900
901                 /* Check, that this local address finally disappeared. */
902                 if (gone &&
903                     inet_addr_type(dev_net(dev), ifa->ifa_local) != RTN_LOCAL) {
904                         /* And the last, but not the least thing.
905                          * We must flush stray FIB entries.
906                          *
907                          * First of all, we scan fib_info list searching
908                          * for stray nexthop entries, then ignite fib_flush.
909                          */
910                         if (fib_sync_down_addr(dev_net(dev), ifa->ifa_local))
911                                 fib_flush(dev_net(dev));
912                 }
913         }
914 #undef LOCAL_OK
915 #undef BRD_OK
916 #undef BRD0_OK
917 #undef BRD1_OK
918 }
919
920 static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
921 {
922
923         struct fib_result       res;
924         struct flowi4           fl4 = {
925                 .flowi4_mark = frn->fl_mark,
926                 .daddr = frn->fl_addr,
927                 .flowi4_tos = frn->fl_tos,
928                 .flowi4_scope = frn->fl_scope,
929         };
930
931         frn->err = -ENOENT;
932         if (tb) {
933                 local_bh_disable();
934
935                 frn->tb_id = tb->tb_id;
936                 frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
937
938                 if (!frn->err) {
939                         frn->prefixlen = res.prefixlen;
940                         frn->nh_sel = res.nh_sel;
941                         frn->type = res.type;
942                         frn->scope = res.scope;
943                 }
944                 local_bh_enable();
945         }
946 }
947
948 static void nl_fib_input(struct sk_buff *skb)
949 {
950         struct net *net;
951         struct fib_result_nl *frn;
952         struct nlmsghdr *nlh;
953         struct fib_table *tb;
954         u32 portid;
955
956         net = sock_net(skb->sk);
957         nlh = nlmsg_hdr(skb);
958         if (skb->len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len ||
959             nlmsg_len(nlh) < sizeof(*frn))
960                 return;
961
962         skb = netlink_skb_clone(skb, GFP_KERNEL);
963         if (skb == NULL)
964                 return;
965         nlh = nlmsg_hdr(skb);
966
967         frn = (struct fib_result_nl *) nlmsg_data(nlh);
968         tb = fib_get_table(net, frn->tb_id_in);
969
970         nl_fib_lookup(frn, tb);
971
972         portid = NETLINK_CB(skb).portid;      /* netlink portid */
973         NETLINK_CB(skb).portid = 0;        /* from kernel */
974         NETLINK_CB(skb).dst_group = 0;  /* unicast */
975         netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
976 }
977
978 static int __net_init nl_fib_lookup_init(struct net *net)
979 {
980         struct sock *sk;
981         struct netlink_kernel_cfg cfg = {
982                 .input  = nl_fib_input,
983         };
984
985         sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
986         if (sk == NULL)
987                 return -EAFNOSUPPORT;
988         net->ipv4.fibnl = sk;
989         return 0;
990 }
991
992 static void nl_fib_lookup_exit(struct net *net)
993 {
994         netlink_kernel_release(net->ipv4.fibnl);
995         net->ipv4.fibnl = NULL;
996 }
997
998 static void fib_disable_ip(struct net_device *dev, int force)
999 {
1000         if (fib_sync_down_dev(dev, force))
1001                 fib_flush(dev_net(dev));
1002         rt_cache_flush(dev_net(dev));
1003         arp_ifdown(dev);
1004 }
1005
1006 static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
1007 {
1008         struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
1009         struct net_device *dev = ifa->ifa_dev->dev;
1010         struct net *net = dev_net(dev);
1011
1012         switch (event) {
1013         case NETDEV_UP:
1014                 fib_add_ifaddr(ifa);
1015 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1016                 fib_sync_up(dev);
1017 #endif
1018                 atomic_inc(&net->ipv4.dev_addr_genid);
1019                 rt_cache_flush(dev_net(dev));
1020                 break;
1021         case NETDEV_DOWN:
1022                 fib_del_ifaddr(ifa, NULL);
1023                 atomic_inc(&net->ipv4.dev_addr_genid);
1024                 if (ifa->ifa_dev->ifa_list == NULL) {
1025                         /* Last address was deleted from this interface.
1026                          * Disable IP.
1027                          */
1028                         fib_disable_ip(dev, 1);
1029                 } else {
1030                         rt_cache_flush(dev_net(dev));
1031                 }
1032                 break;
1033         }
1034         return NOTIFY_DONE;
1035 }
1036
1037 static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1038 {
1039         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1040         struct in_device *in_dev;
1041         struct net *net = dev_net(dev);
1042
1043         if (event == NETDEV_UNREGISTER) {
1044                 fib_disable_ip(dev, 2);
1045                 rt_flush_dev(dev);
1046                 return NOTIFY_DONE;
1047         }
1048
1049         in_dev = __in_dev_get_rtnl(dev);
1050         if (!in_dev)
1051                 return NOTIFY_DONE;
1052
1053         switch (event) {
1054         case NETDEV_UP:
1055                 for_ifa(in_dev) {
1056                         fib_add_ifaddr(ifa);
1057                 } endfor_ifa(in_dev);
1058 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1059                 fib_sync_up(dev);
1060 #endif
1061                 atomic_inc(&net->ipv4.dev_addr_genid);
1062                 rt_cache_flush(net);
1063                 break;
1064         case NETDEV_DOWN:
1065                 fib_disable_ip(dev, 0);
1066                 break;
1067         case NETDEV_CHANGEMTU:
1068         case NETDEV_CHANGE:
1069                 rt_cache_flush(net);
1070                 break;
1071         }
1072         return NOTIFY_DONE;
1073 }
1074
1075 static struct notifier_block fib_inetaddr_notifier = {
1076         .notifier_call = fib_inetaddr_event,
1077 };
1078
1079 static struct notifier_block fib_netdev_notifier = {
1080         .notifier_call = fib_netdev_event,
1081 };
1082
1083 static int __net_init ip_fib_net_init(struct net *net)
1084 {
1085         int err;
1086         size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
1087
1088         /* Avoid false sharing : Use at least a full cache line */
1089         size = max_t(size_t, size, L1_CACHE_BYTES);
1090
1091         net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
1092         if (net->ipv4.fib_table_hash == NULL)
1093                 return -ENOMEM;
1094
1095         err = fib4_rules_init(net);
1096         if (err < 0)
1097                 goto fail;
1098         return 0;
1099
1100 fail:
1101         kfree(net->ipv4.fib_table_hash);
1102         return err;
1103 }
1104
1105 static void ip_fib_net_exit(struct net *net)
1106 {
1107         unsigned int i;
1108
1109 #ifdef CONFIG_IP_MULTIPLE_TABLES
1110         fib4_rules_exit(net);
1111 #endif
1112
1113         rtnl_lock();
1114         for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
1115                 struct fib_table *tb;
1116                 struct hlist_head *head;
1117                 struct hlist_node *tmp;
1118
1119                 head = &net->ipv4.fib_table_hash[i];
1120                 hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
1121                         hlist_del(&tb->tb_hlist);
1122                         fib_table_flush(tb);
1123                         fib_free_table(tb);
1124                 }
1125         }
1126         rtnl_unlock();
1127         kfree(net->ipv4.fib_table_hash);
1128 }
1129
1130 static int __net_init fib_net_init(struct net *net)
1131 {
1132         int error;
1133
1134 #ifdef CONFIG_IP_ROUTE_CLASSID
1135         net->ipv4.fib_num_tclassid_users = 0;
1136 #endif
1137         error = ip_fib_net_init(net);
1138         if (error < 0)
1139                 goto out;
1140         error = nl_fib_lookup_init(net);
1141         if (error < 0)
1142                 goto out_nlfl;
1143         error = fib_proc_init(net);
1144         if (error < 0)
1145                 goto out_proc;
1146 out:
1147         return error;
1148
1149 out_proc:
1150         nl_fib_lookup_exit(net);
1151 out_nlfl:
1152         ip_fib_net_exit(net);
1153         goto out;
1154 }
1155
1156 static void __net_exit fib_net_exit(struct net *net)
1157 {
1158         fib_proc_exit(net);
1159         nl_fib_lookup_exit(net);
1160         ip_fib_net_exit(net);
1161 }
1162
1163 static struct pernet_operations fib_net_ops = {
1164         .init = fib_net_init,
1165         .exit = fib_net_exit,
1166 };
1167
1168 void __init ip_fib_init(void)
1169 {
1170         rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, NULL);
1171         rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, NULL);
1172         rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, NULL);
1173
1174         register_pernet_subsys(&fib_net_ops);
1175         register_netdevice_notifier(&fib_netdev_notifier);
1176         register_inetaddr_notifier(&fib_inetaddr_notifier);
1177
1178         fib_trie_init();
1179 }