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/module.h>
18 #include <linux/errno.h>
19 #include <linux/types.h>
20 #include <linux/random.h>
21 #include <linux/string.h>
22 #include <linux/socket.h>
23 #include <linux/sockios.h>
24 #include <linux/net.h>
25 #include <linux/in6.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_arp.h>
28 #include <linux/route.h>
29 #include <linux/init.h>
30 #include <linux/proc_fs.h>
31 #include <linux/seq_file.h>
32 #include <linux/slab.h>
33
34 #include <net/net_namespace.h>
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, const struct in6_addr *addr);
48
49 /* Big ac list lock for all the sockets */
50 static DEFINE_SPINLOCK(ipv6_sk_ac_lock);
51
52
53 /*
54 * socket join an anycast group
55 */
56
ipv6_sock_ac_join(struct sock * sk,int ifindex,const struct in6_addr * addr)57 int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
58 {
59 struct ipv6_pinfo *np = inet6_sk(sk);
60 struct net_device *dev = NULL;
61 struct inet6_dev *idev;
62 struct ipv6_ac_socklist *pac;
63 struct net *net = sock_net(sk);
64 int ishost = !net->ipv6.devconf_all->forwarding;
65 int err = 0;
66
67 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
68 return -EPERM;
69 if (ipv6_addr_is_multicast(addr))
70 return -EINVAL;
71 if (ipv6_chk_addr(net, addr, NULL, 0))
72 return -EINVAL;
73
74 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
75 if (pac == NULL)
76 return -ENOMEM;
77 pac->acl_next = NULL;
78 pac->acl_addr = *addr;
79
80 rcu_read_lock();
81 if (ifindex == 0) {
82 struct rt6_info *rt;
83
84 rt = rt6_lookup(net, addr, NULL, 0, 0);
85 if (rt) {
86 dev = rt->dst.dev;
87 ip6_rt_put(rt);
88 } else if (ishost) {
89 err = -EADDRNOTAVAIL;
90 goto error;
91 } else {
92 /* router, no matching interface: just pick one */
93 dev = dev_get_by_flags_rcu(net, IFF_UP,
94 IFF_UP | IFF_LOOPBACK);
95 }
96 } else
97 dev = dev_get_by_index_rcu(net, ifindex);
98
99 if (dev == NULL) {
100 err = -ENODEV;
101 goto error;
102 }
103
104 idev = __in6_dev_get(dev);
105 if (!idev) {
106 if (ifindex)
107 err = -ENODEV;
108 else
109 err = -EADDRNOTAVAIL;
110 goto error;
111 }
112 /* reset ishost, now that we have a specific device */
113 ishost = !idev->cnf.forwarding;
114
115 pac->acl_ifindex = dev->ifindex;
116
117 /* XXX
118 * For hosts, allow link-local or matching prefix anycasts.
119 * This obviates the need for propagating anycast routes while
120 * still allowing some non-router anycast participation.
121 */
122 if (!ipv6_chk_prefix(addr, dev)) {
123 if (ishost)
124 err = -EADDRNOTAVAIL;
125 if (err)
126 goto error;
127 }
128
129 err = ipv6_dev_ac_inc(dev, addr);
130 if (!err) {
131 spin_lock_bh(&ipv6_sk_ac_lock);
132 pac->acl_next = np->ipv6_ac_list;
133 np->ipv6_ac_list = pac;
134 spin_unlock_bh(&ipv6_sk_ac_lock);
135 pac = NULL;
136 }
137
138 error:
139 rcu_read_unlock();
140 if (pac)
141 sock_kfree_s(sk, pac, sizeof(*pac));
142 return err;
143 }
144
145 /*
146 * socket leave an anycast group
147 */
ipv6_sock_ac_drop(struct sock * sk,int ifindex,const struct in6_addr * addr)148 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
149 {
150 struct ipv6_pinfo *np = inet6_sk(sk);
151 struct net_device *dev;
152 struct ipv6_ac_socklist *pac, *prev_pac;
153 struct net *net = sock_net(sk);
154
155 spin_lock_bh(&ipv6_sk_ac_lock);
156 prev_pac = NULL;
157 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
158 if ((ifindex == 0 || pac->acl_ifindex == ifindex) &&
159 ipv6_addr_equal(&pac->acl_addr, addr))
160 break;
161 prev_pac = pac;
162 }
163 if (!pac) {
164 spin_unlock_bh(&ipv6_sk_ac_lock);
165 return -ENOENT;
166 }
167 if (prev_pac)
168 prev_pac->acl_next = pac->acl_next;
169 else
170 np->ipv6_ac_list = pac->acl_next;
171
172 spin_unlock_bh(&ipv6_sk_ac_lock);
173
174 rcu_read_lock();
175 dev = dev_get_by_index_rcu(net, pac->acl_ifindex);
176 if (dev)
177 ipv6_dev_ac_dec(dev, &pac->acl_addr);
178 rcu_read_unlock();
179
180 sock_kfree_s(sk, pac, sizeof(*pac));
181 return 0;
182 }
183
ipv6_sock_ac_close(struct sock * sk)184 void ipv6_sock_ac_close(struct sock *sk)
185 {
186 struct ipv6_pinfo *np = inet6_sk(sk);
187 struct net_device *dev = NULL;
188 struct ipv6_ac_socklist *pac;
189 struct net *net = sock_net(sk);
190 int prev_index;
191
192 if (!np->ipv6_ac_list)
193 return;
194
195 spin_lock_bh(&ipv6_sk_ac_lock);
196 pac = np->ipv6_ac_list;
197 np->ipv6_ac_list = NULL;
198 spin_unlock_bh(&ipv6_sk_ac_lock);
199
200 prev_index = 0;
201 rcu_read_lock();
202 while (pac) {
203 struct ipv6_ac_socklist *next = pac->acl_next;
204
205 if (pac->acl_ifindex != prev_index) {
206 dev = dev_get_by_index_rcu(net, pac->acl_ifindex);
207 prev_index = pac->acl_ifindex;
208 }
209 if (dev)
210 ipv6_dev_ac_dec(dev, &pac->acl_addr);
211 sock_kfree_s(sk, pac, sizeof(*pac));
212 pac = next;
213 }
214 rcu_read_unlock();
215 }
216
aca_put(struct ifacaddr6 * ac)217 static void aca_put(struct ifacaddr6 *ac)
218 {
219 if (atomic_dec_and_test(&ac->aca_refcnt)) {
220 in6_dev_put(ac->aca_idev);
221 dst_release(&ac->aca_rt->dst);
222 kfree(ac);
223 }
224 }
225
226 /*
227 * device anycast group inc (add if not found)
228 */
ipv6_dev_ac_inc(struct net_device * dev,const struct in6_addr * addr)229 int ipv6_dev_ac_inc(struct net_device *dev, const struct in6_addr *addr)
230 {
231 struct ifacaddr6 *aca;
232 struct inet6_dev *idev;
233 struct rt6_info *rt;
234 int err;
235
236 idev = in6_dev_get(dev);
237
238 if (idev == NULL)
239 return -EINVAL;
240
241 write_lock_bh(&idev->lock);
242 if (idev->dead) {
243 err = -ENODEV;
244 goto out;
245 }
246
247 for (aca = idev->ac_list; aca; aca = aca->aca_next) {
248 if (ipv6_addr_equal(&aca->aca_addr, addr)) {
249 aca->aca_users++;
250 err = 0;
251 goto out;
252 }
253 }
254
255 /*
256 * not found: create a new one.
257 */
258
259 aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC);
260
261 if (aca == NULL) {
262 err = -ENOMEM;
263 goto out;
264 }
265
266 rt = addrconf_dst_alloc(idev, addr, true);
267 if (IS_ERR(rt)) {
268 kfree(aca);
269 err = PTR_ERR(rt);
270 goto out;
271 }
272
273 aca->aca_addr = *addr;
274 aca->aca_idev = idev;
275 aca->aca_rt = rt;
276 aca->aca_users = 1;
277 /* aca_tstamp should be updated upon changes */
278 aca->aca_cstamp = aca->aca_tstamp = jiffies;
279 atomic_set(&aca->aca_refcnt, 2);
280 spin_lock_init(&aca->aca_lock);
281
282 aca->aca_next = idev->ac_list;
283 idev->ac_list = aca;
284 write_unlock_bh(&idev->lock);
285
286 ip6_ins_rt(rt);
287
288 addrconf_join_solict(dev, &aca->aca_addr);
289
290 aca_put(aca);
291 return 0;
292 out:
293 write_unlock_bh(&idev->lock);
294 in6_dev_put(idev);
295 return err;
296 }
297
298 /*
299 * device anycast group decrement
300 */
__ipv6_dev_ac_dec(struct inet6_dev * idev,const struct in6_addr * addr)301 int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
302 {
303 struct ifacaddr6 *aca, *prev_aca;
304
305 write_lock_bh(&idev->lock);
306 prev_aca = NULL;
307 for (aca = idev->ac_list; aca; aca = aca->aca_next) {
308 if (ipv6_addr_equal(&aca->aca_addr, addr))
309 break;
310 prev_aca = aca;
311 }
312 if (!aca) {
313 write_unlock_bh(&idev->lock);
314 return -ENOENT;
315 }
316 if (--aca->aca_users > 0) {
317 write_unlock_bh(&idev->lock);
318 return 0;
319 }
320 if (prev_aca)
321 prev_aca->aca_next = aca->aca_next;
322 else
323 idev->ac_list = aca->aca_next;
324 write_unlock_bh(&idev->lock);
325 addrconf_leave_solict(idev, &aca->aca_addr);
326
327 dst_hold(&aca->aca_rt->dst);
328 ip6_del_rt(aca->aca_rt);
329
330 aca_put(aca);
331 return 0;
332 }
333
334 /* called with rcu_read_lock() */
ipv6_dev_ac_dec(struct net_device * dev,const struct in6_addr * addr)335 static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr)
336 {
337 struct inet6_dev *idev = __in6_dev_get(dev);
338
339 if (idev == NULL)
340 return -ENODEV;
341 return __ipv6_dev_ac_dec(idev, addr);
342 }
343
ipv6_ac_destroy_dev(struct inet6_dev * idev)344 void ipv6_ac_destroy_dev(struct inet6_dev *idev)
345 {
346 struct ifacaddr6 *aca;
347
348 write_lock_bh(&idev->lock);
349 while ((aca = idev->ac_list) != NULL) {
350 idev->ac_list = aca->aca_next;
351 write_unlock_bh(&idev->lock);
352
353 addrconf_leave_solict(idev, &aca->aca_addr);
354
355 dst_hold(&aca->aca_rt->dst);
356 ip6_del_rt(aca->aca_rt);
357
358 aca_put(aca);
359
360 write_lock_bh(&idev->lock);
361 }
362 write_unlock_bh(&idev->lock);
363 }
364
365 /*
366 * check if the interface has this anycast address
367 * called with rcu_read_lock()
368 */
ipv6_chk_acast_dev(struct net_device * dev,const struct in6_addr * addr)369 static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr)
370 {
371 struct inet6_dev *idev;
372 struct ifacaddr6 *aca;
373
374 idev = __in6_dev_get(dev);
375 if (idev) {
376 read_lock_bh(&idev->lock);
377 for (aca = idev->ac_list; aca; aca = aca->aca_next)
378 if (ipv6_addr_equal(&aca->aca_addr, addr))
379 break;
380 read_unlock_bh(&idev->lock);
381 return aca != NULL;
382 }
383 return false;
384 }
385
386 /*
387 * check if given interface (or any, if dev==0) has this anycast address
388 */
ipv6_chk_acast_addr(struct net * net,struct net_device * dev,const struct in6_addr * addr)389 bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev,
390 const struct in6_addr *addr)
391 {
392 bool found = false;
393
394 rcu_read_lock();
395 if (dev)
396 found = ipv6_chk_acast_dev(dev, addr);
397 else
398 for_each_netdev_rcu(net, dev)
399 if (ipv6_chk_acast_dev(dev, addr)) {
400 found = true;
401 break;
402 }
403 rcu_read_unlock();
404 return found;
405 }
406
407
408 #ifdef CONFIG_PROC_FS
409 struct ac6_iter_state {
410 struct seq_net_private p;
411 struct net_device *dev;
412 struct inet6_dev *idev;
413 };
414
415 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private)
416
ac6_get_first(struct seq_file * seq)417 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
418 {
419 struct ifacaddr6 *im = NULL;
420 struct ac6_iter_state *state = ac6_seq_private(seq);
421 struct net *net = seq_file_net(seq);
422
423 state->idev = NULL;
424 for_each_netdev_rcu(net, state->dev) {
425 struct inet6_dev *idev;
426 idev = __in6_dev_get(state->dev);
427 if (!idev)
428 continue;
429 read_lock_bh(&idev->lock);
430 im = idev->ac_list;
431 if (im) {
432 state->idev = idev;
433 break;
434 }
435 read_unlock_bh(&idev->lock);
436 }
437 return im;
438 }
439
ac6_get_next(struct seq_file * seq,struct ifacaddr6 * im)440 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im)
441 {
442 struct ac6_iter_state *state = ac6_seq_private(seq);
443
444 im = im->aca_next;
445 while (!im) {
446 if (likely(state->idev != NULL))
447 read_unlock_bh(&state->idev->lock);
448
449 state->dev = next_net_device_rcu(state->dev);
450 if (!state->dev) {
451 state->idev = NULL;
452 break;
453 }
454 state->idev = __in6_dev_get(state->dev);
455 if (!state->idev)
456 continue;
457 read_lock_bh(&state->idev->lock);
458 im = state->idev->ac_list;
459 }
460 return im;
461 }
462
ac6_get_idx(struct seq_file * seq,loff_t pos)463 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
464 {
465 struct ifacaddr6 *im = ac6_get_first(seq);
466 if (im)
467 while (pos && (im = ac6_get_next(seq, im)) != NULL)
468 --pos;
469 return pos ? NULL : im;
470 }
471
ac6_seq_start(struct seq_file * seq,loff_t * pos)472 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
473 __acquires(RCU)
474 {
475 rcu_read_lock();
476 return ac6_get_idx(seq, *pos);
477 }
478
ac6_seq_next(struct seq_file * seq,void * v,loff_t * pos)479 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
480 {
481 struct ifacaddr6 *im = ac6_get_next(seq, v);
482
483 ++*pos;
484 return im;
485 }
486
ac6_seq_stop(struct seq_file * seq,void * v)487 static void ac6_seq_stop(struct seq_file *seq, void *v)
488 __releases(RCU)
489 {
490 struct ac6_iter_state *state = ac6_seq_private(seq);
491
492 if (likely(state->idev != NULL)) {
493 read_unlock_bh(&state->idev->lock);
494 state->idev = NULL;
495 }
496 rcu_read_unlock();
497 }
498
ac6_seq_show(struct seq_file * seq,void * v)499 static int ac6_seq_show(struct seq_file *seq, void *v)
500 {
501 struct ifacaddr6 *im = (struct ifacaddr6 *)v;
502 struct ac6_iter_state *state = ac6_seq_private(seq);
503
504 seq_printf(seq, "%-4d %-15s %pi6 %5d\n",
505 state->dev->ifindex, state->dev->name,
506 &im->aca_addr, im->aca_users);
507 return 0;
508 }
509
510 static const struct seq_operations ac6_seq_ops = {
511 .start = ac6_seq_start,
512 .next = ac6_seq_next,
513 .stop = ac6_seq_stop,
514 .show = ac6_seq_show,
515 };
516
ac6_seq_open(struct inode * inode,struct file * file)517 static int ac6_seq_open(struct inode *inode, struct file *file)
518 {
519 return seq_open_net(inode, file, &ac6_seq_ops,
520 sizeof(struct ac6_iter_state));
521 }
522
523 static const struct file_operations ac6_seq_fops = {
524 .owner = THIS_MODULE,
525 .open = ac6_seq_open,
526 .read = seq_read,
527 .llseek = seq_lseek,
528 .release = seq_release_net,
529 };
530
ac6_proc_init(struct net * net)531 int __net_init ac6_proc_init(struct net *net)
532 {
533 if (!proc_create("anycast6", S_IRUGO, net->proc_net, &ac6_seq_fops))
534 return -ENOMEM;
535
536 return 0;
537 }
538
ac6_proc_exit(struct net * net)539 void ac6_proc_exit(struct net *net)
540 {
541 remove_proc_entry("anycast6", net->proc_net);
542 }
543 #endif
544
545