Pull bugzilla-5737 into release branch
[linux-2.6] / net / ipv6 / anycast.c
1 /*
2  *      Anycast support for IPv6
3  *      Linux INET6 implementation 
4  *
5  *      Authors:
6  *      David L Stevens (dlstevens@us.ibm.com)
7  *
8  *      based heavily on net/ipv6/mcast.c
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/capability.h>
17 #include <linux/config.h>
18 #include <linux/module.h>
19 #include <linux/errno.h>
20 #include <linux/types.h>
21 #include <linux/random.h>
22 #include <linux/string.h>
23 #include <linux/socket.h>
24 #include <linux/sockios.h>
25 #include <linux/sched.h>
26 #include <linux/net.h>
27 #include <linux/in6.h>
28 #include <linux/netdevice.h>
29 #include <linux/if_arp.h>
30 #include <linux/route.h>
31 #include <linux/init.h>
32 #include <linux/proc_fs.h>
33 #include <linux/seq_file.h>
34
35 #include <net/sock.h>
36 #include <net/snmp.h>
37
38 #include <net/ipv6.h>
39 #include <net/protocol.h>
40 #include <net/if_inet6.h>
41 #include <net/ndisc.h>
42 #include <net/addrconf.h>
43 #include <net/ip6_route.h>
44
45 #include <net/checksum.h>
46
47 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr);
48
49 /* Big ac list lock for all the sockets */
50 static DEFINE_RWLOCK(ipv6_sk_ac_lock);
51
52 static int
53 ip6_onlink(struct in6_addr *addr, struct net_device *dev)
54 {
55         struct inet6_dev        *idev;
56         struct inet6_ifaddr     *ifa;
57         int     onlink;
58
59         onlink = 0;
60         read_lock(&addrconf_lock);
61         idev = __in6_dev_get(dev);
62         if (idev) {
63                 read_lock_bh(&idev->lock);
64                 for (ifa=idev->addr_list; ifa; ifa=ifa->if_next) {
65                         onlink = ipv6_prefix_equal(addr, &ifa->addr,
66                                                    ifa->prefix_len);
67                         if (onlink)
68                                 break;
69                 }
70                 read_unlock_bh(&idev->lock);
71         }
72         read_unlock(&addrconf_lock);
73         return onlink;
74 }
75
76 /*
77  *      socket join an anycast group
78  */
79
80 int ipv6_sock_ac_join(struct sock *sk, int ifindex, struct in6_addr *addr)
81 {
82         struct ipv6_pinfo *np = inet6_sk(sk);
83         struct net_device *dev = NULL;
84         struct inet6_dev *idev;
85         struct ipv6_ac_socklist *pac;
86         int     ishost = !ipv6_devconf.forwarding;
87         int     err = 0;
88
89         if (!capable(CAP_NET_ADMIN))
90                 return -EPERM;
91         if (ipv6_addr_is_multicast(addr))
92                 return -EINVAL;
93         if (ipv6_chk_addr(addr, NULL, 0))
94                 return -EINVAL;
95
96         pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
97         if (pac == NULL)
98                 return -ENOMEM;
99         pac->acl_next = NULL;
100         ipv6_addr_copy(&pac->acl_addr, addr);
101
102         if (ifindex == 0) {
103                 struct rt6_info *rt;
104
105                 rt = rt6_lookup(addr, NULL, 0, 0);
106                 if (rt) {
107                         dev = rt->rt6i_dev;
108                         dev_hold(dev);
109                         dst_release(&rt->u.dst);
110                 } else if (ishost) {
111                         err = -EADDRNOTAVAIL;
112                         goto out_free_pac;
113                 } else {
114                         /* router, no matching interface: just pick one */
115
116                         dev = dev_get_by_flags(IFF_UP, IFF_UP|IFF_LOOPBACK);
117                 }
118         } else
119                 dev = dev_get_by_index(ifindex);
120
121         if (dev == NULL) {
122                 err = -ENODEV;
123                 goto out_free_pac;
124         }
125
126         idev = in6_dev_get(dev);
127         if (!idev) {
128                 if (ifindex)
129                         err = -ENODEV;
130                 else
131                         err = -EADDRNOTAVAIL;
132                 goto out_dev_put;
133         }
134         /* reset ishost, now that we have a specific device */
135         ishost = !idev->cnf.forwarding;
136         in6_dev_put(idev);
137
138         pac->acl_ifindex = dev->ifindex;
139
140         /* XXX
141          * For hosts, allow link-local or matching prefix anycasts.
142          * This obviates the need for propagating anycast routes while
143          * still allowing some non-router anycast participation.
144          */
145         if (!ip6_onlink(addr, dev)) {
146                 if (ishost)
147                         err = -EADDRNOTAVAIL;
148                 if (err)
149                         goto out_dev_put;
150         }
151
152         err = ipv6_dev_ac_inc(dev, addr);
153         if (err)
154                 goto out_dev_put;
155
156         write_lock_bh(&ipv6_sk_ac_lock);
157         pac->acl_next = np->ipv6_ac_list;
158         np->ipv6_ac_list = pac;
159         write_unlock_bh(&ipv6_sk_ac_lock);
160
161         dev_put(dev);
162
163         return 0;
164
165 out_dev_put:
166         dev_put(dev);
167 out_free_pac:
168         sock_kfree_s(sk, pac, sizeof(*pac));
169         return err;
170 }
171
172 /*
173  *      socket leave an anycast group
174  */
175 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, struct in6_addr *addr)
176 {
177         struct ipv6_pinfo *np = inet6_sk(sk);
178         struct net_device *dev;
179         struct ipv6_ac_socklist *pac, *prev_pac;
180
181         write_lock_bh(&ipv6_sk_ac_lock);
182         prev_pac = NULL;
183         for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
184                 if ((ifindex == 0 || pac->acl_ifindex == ifindex) &&
185                      ipv6_addr_equal(&pac->acl_addr, addr))
186                         break;
187                 prev_pac = pac;
188         }
189         if (!pac) {
190                 write_unlock_bh(&ipv6_sk_ac_lock);
191                 return -ENOENT;
192         }
193         if (prev_pac)
194                 prev_pac->acl_next = pac->acl_next;
195         else
196                 np->ipv6_ac_list = pac->acl_next;
197
198         write_unlock_bh(&ipv6_sk_ac_lock);
199
200         dev = dev_get_by_index(pac->acl_ifindex);
201         if (dev) {
202                 ipv6_dev_ac_dec(dev, &pac->acl_addr);
203                 dev_put(dev);
204         }
205         sock_kfree_s(sk, pac, sizeof(*pac));
206         return 0;
207 }
208
209 void ipv6_sock_ac_close(struct sock *sk)
210 {
211         struct ipv6_pinfo *np = inet6_sk(sk);
212         struct net_device *dev = NULL;
213         struct ipv6_ac_socklist *pac;
214         int     prev_index;
215
216         write_lock_bh(&ipv6_sk_ac_lock);
217         pac = np->ipv6_ac_list;
218         np->ipv6_ac_list = NULL;
219         write_unlock_bh(&ipv6_sk_ac_lock);
220
221         prev_index = 0;
222         while (pac) {
223                 struct ipv6_ac_socklist *next = pac->acl_next;
224
225                 if (pac->acl_ifindex != prev_index) {
226                         if (dev)
227                                 dev_put(dev);
228                         dev = dev_get_by_index(pac->acl_ifindex);
229                         prev_index = pac->acl_ifindex;
230                 }
231                 if (dev)
232                         ipv6_dev_ac_dec(dev, &pac->acl_addr);
233                 sock_kfree_s(sk, pac, sizeof(*pac));
234                 pac = next;
235         }
236         if (dev)
237                 dev_put(dev);
238 }
239
240 #if 0
241 /* The function is not used, which is funny. Apparently, author
242  * supposed to use it to filter out datagrams inside udp/raw but forgot.
243  *
244  * It is OK, anycasts are not special comparing to delivery to unicasts.
245  */
246
247 int inet6_ac_check(struct sock *sk, struct in6_addr *addr, int ifindex)
248 {
249         struct ipv6_ac_socklist *pac;
250         struct ipv6_pinfo *np = inet6_sk(sk);
251         int     found;
252
253         found = 0;
254         read_lock(&ipv6_sk_ac_lock);
255         for (pac=np->ipv6_ac_list; pac; pac=pac->acl_next) {
256                 if (ifindex && pac->acl_ifindex != ifindex)
257                         continue;
258                 found = ipv6_addr_equal(&pac->acl_addr, addr);
259                 if (found)
260                         break;
261         }
262         read_unlock(&ipv6_sk_ac_lock);
263
264         return found;
265 }
266
267 #endif
268
269 static void aca_put(struct ifacaddr6 *ac)
270 {
271         if (atomic_dec_and_test(&ac->aca_refcnt)) {
272                 in6_dev_put(ac->aca_idev);
273                 dst_release(&ac->aca_rt->u.dst);
274                 kfree(ac);
275         }
276 }
277
278 /*
279  *      device anycast group inc (add if not found)
280  */
281 int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr)
282 {
283         struct ifacaddr6 *aca;
284         struct inet6_dev *idev;
285         struct rt6_info *rt;
286         int err;
287
288         idev = in6_dev_get(dev);
289
290         if (idev == NULL)
291                 return -EINVAL;
292
293         write_lock_bh(&idev->lock);
294         if (idev->dead) {
295                 err = -ENODEV;
296                 goto out;
297         }
298
299         for (aca = idev->ac_list; aca; aca = aca->aca_next) {
300                 if (ipv6_addr_equal(&aca->aca_addr, addr)) {
301                         aca->aca_users++;
302                         err = 0;
303                         goto out;
304                 }
305         }
306
307         /*
308          *      not found: create a new one.
309          */
310
311         aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC);
312
313         if (aca == NULL) {
314                 err = -ENOMEM;
315                 goto out;
316         }
317
318         rt = addrconf_dst_alloc(idev, addr, 1);
319         if (IS_ERR(rt)) {
320                 kfree(aca);
321                 err = PTR_ERR(rt);
322                 goto out;
323         }
324
325         ipv6_addr_copy(&aca->aca_addr, addr);
326         aca->aca_idev = idev;
327         aca->aca_rt = rt;
328         aca->aca_users = 1;
329         /* aca_tstamp should be updated upon changes */
330         aca->aca_cstamp = aca->aca_tstamp = jiffies;
331         atomic_set(&aca->aca_refcnt, 2);
332         spin_lock_init(&aca->aca_lock);
333
334         aca->aca_next = idev->ac_list;
335         idev->ac_list = aca;
336         write_unlock_bh(&idev->lock);
337
338         dst_hold(&rt->u.dst);
339         if (ip6_ins_rt(rt, NULL, NULL, NULL))
340                 dst_release(&rt->u.dst);
341
342         addrconf_join_solict(dev, &aca->aca_addr);
343
344         aca_put(aca);
345         return 0;
346 out:
347         write_unlock_bh(&idev->lock);
348         in6_dev_put(idev);
349         return err;
350 }
351
352 /*
353  *      device anycast group decrement
354  */
355 int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr)
356 {
357         struct ifacaddr6 *aca, *prev_aca;
358
359         write_lock_bh(&idev->lock);
360         prev_aca = NULL;
361         for (aca = idev->ac_list; aca; aca = aca->aca_next) {
362                 if (ipv6_addr_equal(&aca->aca_addr, addr))
363                         break;
364                 prev_aca = aca;
365         }
366         if (!aca) {
367                 write_unlock_bh(&idev->lock);
368                 return -ENOENT;
369         }
370         if (--aca->aca_users > 0) {
371                 write_unlock_bh(&idev->lock);
372                 return 0;
373         }
374         if (prev_aca)
375                 prev_aca->aca_next = aca->aca_next;
376         else
377                 idev->ac_list = aca->aca_next;
378         write_unlock_bh(&idev->lock);
379         addrconf_leave_solict(idev, &aca->aca_addr);
380
381         dst_hold(&aca->aca_rt->u.dst);
382         if (ip6_del_rt(aca->aca_rt, NULL, NULL, NULL))
383                 dst_free(&aca->aca_rt->u.dst);
384         else
385                 dst_release(&aca->aca_rt->u.dst);
386
387         aca_put(aca);
388         return 0;
389 }
390
391 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
392 {
393         int ret;
394         struct inet6_dev *idev = in6_dev_get(dev);
395         if (idev == NULL)
396                 return -ENODEV;
397         ret = __ipv6_dev_ac_dec(idev, addr);
398         in6_dev_put(idev);
399         return ret;
400 }
401         
402 /*
403  *      check if the interface has this anycast address
404  */
405 static int ipv6_chk_acast_dev(struct net_device *dev, struct in6_addr *addr)
406 {
407         struct inet6_dev *idev;
408         struct ifacaddr6 *aca;
409
410         idev = in6_dev_get(dev);
411         if (idev) {
412                 read_lock_bh(&idev->lock);
413                 for (aca = idev->ac_list; aca; aca = aca->aca_next)
414                         if (ipv6_addr_equal(&aca->aca_addr, addr))
415                                 break;
416                 read_unlock_bh(&idev->lock);
417                 in6_dev_put(idev);
418                 return aca != 0;
419         }
420         return 0;
421 }
422
423 /*
424  *      check if given interface (or any, if dev==0) has this anycast address
425  */
426 int ipv6_chk_acast_addr(struct net_device *dev, struct in6_addr *addr)
427 {
428         if (dev)
429                 return ipv6_chk_acast_dev(dev, addr);
430         read_lock(&dev_base_lock);
431         for (dev=dev_base; dev; dev=dev->next)
432                 if (ipv6_chk_acast_dev(dev, addr))
433                         break;
434         read_unlock(&dev_base_lock);
435         return dev != 0;
436 }
437
438
439 #ifdef CONFIG_PROC_FS
440 struct ac6_iter_state {
441         struct net_device *dev;
442         struct inet6_dev *idev;
443 };
444
445 #define ac6_seq_private(seq)    ((struct ac6_iter_state *)(seq)->private)
446
447 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
448 {
449         struct ifacaddr6 *im = NULL;
450         struct ac6_iter_state *state = ac6_seq_private(seq);
451
452         for (state->dev = dev_base, state->idev = NULL;
453              state->dev;
454              state->dev = state->dev->next) {
455                 struct inet6_dev *idev;
456                 idev = in6_dev_get(state->dev);
457                 if (!idev)
458                         continue;
459                 read_lock_bh(&idev->lock);
460                 im = idev->ac_list;
461                 if (im) {
462                         state->idev = idev;
463                         break;
464                 }
465                 read_unlock_bh(&idev->lock);
466         }
467         return im;
468 }
469
470 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im)
471 {
472         struct ac6_iter_state *state = ac6_seq_private(seq);
473
474         im = im->aca_next;
475         while (!im) {
476                 if (likely(state->idev != NULL)) {
477                         read_unlock_bh(&state->idev->lock);
478                         in6_dev_put(state->idev);
479                 }
480                 state->dev = state->dev->next;
481                 if (!state->dev) {
482                         state->idev = NULL;
483                         break;
484                 }
485                 state->idev = in6_dev_get(state->dev);
486                 if (!state->idev)
487                         continue;
488                 read_lock_bh(&state->idev->lock);
489                 im = state->idev->ac_list;
490         }
491         return im;
492 }
493
494 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
495 {
496         struct ifacaddr6 *im = ac6_get_first(seq);
497         if (im)
498                 while (pos && (im = ac6_get_next(seq, im)) != NULL)
499                         --pos;
500         return pos ? NULL : im;
501 }
502
503 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
504 {
505         read_lock(&dev_base_lock);
506         return ac6_get_idx(seq, *pos);
507 }
508
509 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
510 {
511         struct ifacaddr6 *im;
512         im = ac6_get_next(seq, v);
513         ++*pos;
514         return im;
515 }
516
517 static void ac6_seq_stop(struct seq_file *seq, void *v)
518 {
519         struct ac6_iter_state *state = ac6_seq_private(seq);
520         if (likely(state->idev != NULL)) {
521                 read_unlock_bh(&state->idev->lock);
522                 in6_dev_put(state->idev);
523         }
524         read_unlock(&dev_base_lock);
525 }
526
527 static int ac6_seq_show(struct seq_file *seq, void *v)
528 {
529         struct ifacaddr6 *im = (struct ifacaddr6 *)v;
530         struct ac6_iter_state *state = ac6_seq_private(seq);
531
532         seq_printf(seq,
533                    "%-4d %-15s " NIP6_SEQFMT " %5d\n",
534                    state->dev->ifindex, state->dev->name,
535                    NIP6(im->aca_addr),
536                    im->aca_users);
537         return 0;
538 }
539
540 static struct seq_operations ac6_seq_ops = {
541         .start  =       ac6_seq_start,
542         .next   =       ac6_seq_next,
543         .stop   =       ac6_seq_stop,
544         .show   =       ac6_seq_show,
545 };
546
547 static int ac6_seq_open(struct inode *inode, struct file *file)
548 {
549         struct seq_file *seq;
550         int rc = -ENOMEM;
551         struct ac6_iter_state *s = kzalloc(sizeof(*s), GFP_KERNEL);
552
553         if (!s)
554                 goto out;
555
556         rc = seq_open(file, &ac6_seq_ops);
557         if (rc)
558                 goto out_kfree;
559
560         seq = file->private_data;
561         seq->private = s;
562 out:
563         return rc;
564 out_kfree:
565         kfree(s);
566         goto out;
567 }
568
569 static struct file_operations ac6_seq_fops = {
570         .owner          =       THIS_MODULE,
571         .open           =       ac6_seq_open,
572         .read           =       seq_read,
573         .llseek         =       seq_lseek,
574         .release        =       seq_release_private,
575 };
576
577 int __init ac6_proc_init(void)
578 {
579         if (!proc_net_fops_create("anycast6", S_IRUGO, &ac6_seq_fops))
580                 return -ENOMEM;
581
582         return 0;
583 }
584
585 void ac6_proc_exit(void)
586 {
587         proc_net_remove("anycast6");
588 }
589 #endif
590