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/config.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/sched.h>
25 #include <linux/net.h>
26 #include <linux/in6.h>
27 #include <linux/netdevice.h>
28 #include <linux/if_arp.h>
29 #include <linux/route.h>
30 #include <linux/init.h>
31 #include <linux/proc_fs.h>
32 #include <linux/seq_file.h>
33
34 #include <net/sock.h>
35 #include <net/snmp.h>
36
37 #include <net/ipv6.h>
38 #include <net/protocol.h>
39 #include <net/if_inet6.h>
40 #include <net/ndisc.h>
41 #include <net/addrconf.h>
42 #include <net/ip6_route.h>
43
44 #include <net/checksum.h>
45
46 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr);
47
48 /* Big ac list lock for all the sockets */
49 static DEFINE_RWLOCK(ipv6_sk_ac_lock);
50
51 /* XXX ip6_addr_match() and ip6_onlink() really belong in net/core.c */
52
53 static int
54 ip6_addr_match(struct in6_addr *addr1, struct in6_addr *addr2, int prefix)
55 {
56 __u32 mask;
57 int i;
58
59 if (prefix > 128 || prefix < 0)
60 return 0;
61 if (prefix == 0)
62 return 1;
63 for (i=0; i<4; ++i) {
64 if (prefix >= 32)
65 mask = ~0;
66 else
67 mask = htonl(~0 << (32 - prefix));
68 if ((addr1->s6_addr32[i] ^ addr2->s6_addr32[i]) & mask)
69 return 0;
70 prefix -= 32;
71 if (prefix <= 0)
72 break;
73 }
74 return 1;
75 }
76
77 static int
78 ip6_onlink(struct in6_addr *addr, struct net_device *dev)
79 {
80 struct inet6_dev *idev;
81 struct inet6_ifaddr *ifa;
82 int onlink;
83
84 onlink = 0;
85 read_lock(&addrconf_lock);
86 idev = __in6_dev_get(dev);
87 if (idev) {
88 read_lock_bh(&idev->lock);
89 for (ifa=idev->addr_list; ifa; ifa=ifa->if_next) {
90 onlink = ip6_addr_match(addr, &ifa->addr,
91 ifa->prefix_len);
92 if (onlink)
93 break;
94 }
95 read_unlock_bh(&idev->lock);
96 }
97 read_unlock(&addrconf_lock);
98 return onlink;
99 }
100
101 /*
102 * socket join an anycast group
103 */
104
105 int ipv6_sock_ac_join(struct sock *sk, int ifindex, struct in6_addr *addr)
106 {
107 struct ipv6_pinfo *np = inet6_sk(sk);
108 struct net_device *dev = NULL;
109 struct inet6_dev *idev;
110 struct ipv6_ac_socklist *pac;
111 int ishost = !ipv6_devconf.forwarding;
112 int err = 0;
113
114 if (!capable(CAP_NET_ADMIN))
115 return -EPERM;
116 if (ipv6_addr_is_multicast(addr))
117 return -EINVAL;
118 if (ipv6_chk_addr(addr, NULL, 0))
119 return -EINVAL;
120
121 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
122 if (pac == NULL)
123 return -ENOMEM;
124 pac->acl_next = NULL;
125 ipv6_addr_copy(&pac->acl_addr, addr);
126
127 if (ifindex == 0) {
128 struct rt6_info *rt;
129
130 rt = rt6_lookup(addr, NULL, 0, 0);
131 if (rt) {
132 dev = rt->rt6i_dev;
133 dev_hold(dev);
134 dst_release(&rt->u.dst);
135 } else if (ishost) {
136 err = -EADDRNOTAVAIL;
137 goto out_free_pac;
138 } else {
139 /* router, no matching interface: just pick one */
140
141 dev = dev_get_by_flags(IFF_UP, IFF_UP|IFF_LOOPBACK);
142 }
143 } else
144 dev = dev_get_by_index(ifindex);
145
146 if (dev == NULL) {
147 err = -ENODEV;
148 goto out_free_pac;
149 }
150
151 idev = in6_dev_get(dev);
152 if (!idev) {
153 if (ifindex)
154 err = -ENODEV;
155 else
156 err = -EADDRNOTAVAIL;
157 goto out_dev_put;
158 }
159 /* reset ishost, now that we have a specific device */
160 ishost = !idev->cnf.forwarding;
161 in6_dev_put(idev);
162
163 pac->acl_ifindex = dev->ifindex;
164
165 /* XXX
166 * For hosts, allow link-local or matching prefix anycasts.
167 * This obviates the need for propagating anycast routes while
168 * still allowing some non-router anycast participation.
169 */
170 if (!ip6_onlink(addr, dev)) {
171 if (ishost)
172 err = -EADDRNOTAVAIL;
173 if (err)
174 goto out_dev_put;
175 }
176
177 err = ipv6_dev_ac_inc(dev, addr);
178 if (err)
179 goto out_dev_put;
180
181 write_lock_bh(&ipv6_sk_ac_lock);
182 pac->acl_next = np->ipv6_ac_list;
183 np->ipv6_ac_list = pac;
184 write_unlock_bh(&ipv6_sk_ac_lock);
185
186 dev_put(dev);
187
188 return 0;
189
190 out_dev_put:
191 dev_put(dev);
192 out_free_pac:
193 sock_kfree_s(sk, pac, sizeof(*pac));
194 return err;
195 }
196
197 /*
198 * socket leave an anycast group
199 */
200 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, struct in6_addr *addr)
201 {
202 struct ipv6_pinfo *np = inet6_sk(sk);
203 struct net_device *dev;
204 struct ipv6_ac_socklist *pac, *prev_pac;
205
206 write_lock_bh(&ipv6_sk_ac_lock);
207 prev_pac = NULL;
208 for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
209 if ((ifindex == 0 || pac->acl_ifindex == ifindex) &&
210 ipv6_addr_equal(&pac->acl_addr, addr))
211 break;
212 prev_pac = pac;
213 }
214 if (!pac) {
215 write_unlock_bh(&ipv6_sk_ac_lock);
216 return -ENOENT;
217 }
218 if (prev_pac)
219 prev_pac->acl_next = pac->acl_next;
220 else
221 np->ipv6_ac_list = pac->acl_next;
222
223 write_unlock_bh(&ipv6_sk_ac_lock);
224
225 dev = dev_get_by_index(pac->acl_ifindex);
226 if (dev) {
227 ipv6_dev_ac_dec(dev, &pac->acl_addr);
228 dev_put(dev);
229 }
230 sock_kfree_s(sk, pac, sizeof(*pac));
231 return 0;
232 }
233
234 void ipv6_sock_ac_close(struct sock *sk)
235 {
236 struct ipv6_pinfo *np = inet6_sk(sk);
237 struct net_device *dev = NULL;
238 struct ipv6_ac_socklist *pac;
239 int prev_index;
240
241 write_lock_bh(&ipv6_sk_ac_lock);
242 pac = np->ipv6_ac_list;
243 np->ipv6_ac_list = NULL;
244 write_unlock_bh(&ipv6_sk_ac_lock);
245
246 prev_index = 0;
247 while (pac) {
248 struct ipv6_ac_socklist *next = pac->acl_next;
249
250 if (pac->acl_ifindex != prev_index) {
251 if (dev)
252 dev_put(dev);
253 dev = dev_get_by_index(pac->acl_ifindex);
254 prev_index = pac->acl_ifindex;
255 }
256 if (dev)
257 ipv6_dev_ac_dec(dev, &pac->acl_addr);
258 sock_kfree_s(sk, pac, sizeof(*pac));
259 pac = next;
260 }
261 if (dev)
262 dev_put(dev);
263 }
264
265 #if 0
266 /* The function is not used, which is funny. Apparently, author
267 * supposed to use it to filter out datagrams inside udp/raw but forgot.
268 *
269 * It is OK, anycasts are not special comparing to delivery to unicasts.
270 */
271
272 int inet6_ac_check(struct sock *sk, struct in6_addr *addr, int ifindex)
273 {
274 struct ipv6_ac_socklist *pac;
275 struct ipv6_pinfo *np = inet6_sk(sk);
276 int found;
277
278 found = 0;
279 read_lock(&ipv6_sk_ac_lock);
280 for (pac=np->ipv6_ac_list; pac; pac=pac->acl_next) {
281 if (ifindex && pac->acl_ifindex != ifindex)
282 continue;
283 found = ipv6_addr_equal(&pac->acl_addr, addr);
284 if (found)
285 break;
286 }
287 read_unlock(&ipv6_sk_ac_lock);
288
289 return found;
290 }
291
292 #endif
293
294 static void aca_put(struct ifacaddr6 *ac)
295 {
296 if (atomic_dec_and_test(&ac->aca_refcnt)) {
297 in6_dev_put(ac->aca_idev);
298 dst_release(&ac->aca_rt->u.dst);
299 kfree(ac);
300 }
301 }
302
303 /*
304 * device anycast group inc (add if not found)
305 */
306 int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr)
307 {
308 struct ifacaddr6 *aca;
309 struct inet6_dev *idev;
310 struct rt6_info *rt;
311 int err;
312
313 idev = in6_dev_get(dev);
314
315 if (idev == NULL)
316 return -EINVAL;
317
318 write_lock_bh(&idev->lock);
319 if (idev->dead) {
320 err = -ENODEV;
321 goto out;
322 }
323
324 for (aca = idev->ac_list; aca; aca = aca->aca_next) {
325 if (ipv6_addr_equal(&aca->aca_addr, addr)) {
326 aca->aca_users++;
327 err = 0;
328 goto out;
329 }
330 }
331
332 /*
333 * not found: create a new one.
334 */
335
336 aca = kmalloc(sizeof(struct ifacaddr6), GFP_ATOMIC);
337
338 if (aca == NULL) {
339 err = -ENOMEM;
340 goto out;
341 }
342
343 rt = addrconf_dst_alloc(idev, addr, 1);
344 if (IS_ERR(rt)) {
345 kfree(aca);
346 err = PTR_ERR(rt);
347 goto out;
348 }
349
350 memset(aca, 0, sizeof(struct ifacaddr6));
351
352 ipv6_addr_copy(&aca->aca_addr, addr);
353 aca->aca_idev = idev;
354 aca->aca_rt = rt;
355 aca->aca_users = 1;
356 /* aca_tstamp should be updated upon changes */
357 aca->aca_cstamp = aca->aca_tstamp = jiffies;
358 atomic_set(&aca->aca_refcnt, 2);
359 spin_lock_init(&aca->aca_lock);
360
361 aca->aca_next = idev->ac_list;
362 idev->ac_list = aca;
363 write_unlock_bh(&idev->lock);
364
365 dst_hold(&rt->u.dst);
366 if (ip6_ins_rt(rt, NULL, NULL))
367 dst_release(&rt->u.dst);
368
369 addrconf_join_solict(dev, &aca->aca_addr);
370
371 aca_put(aca);
372 return 0;
373 out:
374 write_unlock_bh(&idev->lock);
375 in6_dev_put(idev);
376 return err;
377 }
378
379 /*
380 * device anycast group decrement
381 */
382 int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr)
383 {
384 struct ifacaddr6 *aca, *prev_aca;
385
386 write_lock_bh(&idev->lock);
387 prev_aca = NULL;
388 for (aca = idev->ac_list; aca; aca = aca->aca_next) {
389 if (ipv6_addr_equal(&aca->aca_addr, addr))
390 break;
391 prev_aca = aca;
392 }
393 if (!aca) {
394 write_unlock_bh(&idev->lock);
395 return -ENOENT;
396 }
397 if (--aca->aca_users > 0) {
398 write_unlock_bh(&idev->lock);
399 return 0;
400 }
401 if (prev_aca)
402 prev_aca->aca_next = aca->aca_next;
403 else
404 idev->ac_list = aca->aca_next;
405 write_unlock_bh(&idev->lock);
406 addrconf_leave_solict(idev, &aca->aca_addr);
407
408 dst_hold(&aca->aca_rt->u.dst);
409 if (ip6_del_rt(aca->aca_rt, NULL, NULL))
410 dst_free(&aca->aca_rt->u.dst);
411 else
412 dst_release(&aca->aca_rt->u.dst);
413
414 aca_put(aca);
415 return 0;
416 }
417
418 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
419 {
420 int ret;
421 struct inet6_dev *idev = in6_dev_get(dev);
422 if (idev == NULL)
423 return -ENODEV;
424 ret = __ipv6_dev_ac_dec(idev, addr);
425 in6_dev_put(idev);
426 return ret;
427 }
428
429 /*
430 * check if the interface has this anycast address
431 */
432 static int ipv6_chk_acast_dev(struct net_device *dev, struct in6_addr *addr)
433 {
434 struct inet6_dev *idev;
435 struct ifacaddr6 *aca;
436
437 idev = in6_dev_get(dev);
438 if (idev) {
439 read_lock_bh(&idev->lock);
440 for (aca = idev->ac_list; aca; aca = aca->aca_next)
441 if (ipv6_addr_equal(&aca->aca_addr, addr))
442 break;
443 read_unlock_bh(&idev->lock);
444 in6_dev_put(idev);
445 return aca != 0;
446 }
447 return 0;
448 }
449
450 /*
451 * check if given interface (or any, if dev==0) has this anycast address
452 */
453 int ipv6_chk_acast_addr(struct net_device *dev, struct in6_addr *addr)
454 {
455 if (dev)
456 return ipv6_chk_acast_dev(dev, addr);
457 read_lock(&dev_base_lock);
458 for (dev=dev_base; dev; dev=dev->next)
459 if (ipv6_chk_acast_dev(dev, addr))
460 break;
461 read_unlock(&dev_base_lock);
462 return dev != 0;
463 }
464
465
466 #ifdef CONFIG_PROC_FS
467 struct ac6_iter_state {
468 struct net_device *dev;
469 struct inet6_dev *idev;
470 };
471
472 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private)
473
474 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
475 {
476 struct ifacaddr6 *im = NULL;
477 struct ac6_iter_state *state = ac6_seq_private(seq);
478
479 for (state->dev = dev_base, state->idev = NULL;
480 state->dev;
481 state->dev = state->dev->next) {
482 struct inet6_dev *idev;
483 idev = in6_dev_get(state->dev);
484 if (!idev)
485 continue;
486 read_lock_bh(&idev->lock);
487 im = idev->ac_list;
488 if (im) {
489 state->idev = idev;
490 break;
491 }
492 read_unlock_bh(&idev->lock);
493 }
494 return im;
495 }
496
497 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im)
498 {
499 struct ac6_iter_state *state = ac6_seq_private(seq);
500
501 im = im->aca_next;
502 while (!im) {
503 if (likely(state->idev != NULL)) {
504 read_unlock_bh(&state->idev->lock);
505 in6_dev_put(state->idev);
506 }
507 state->dev = state->dev->next;
508 if (!state->dev) {
509 state->idev = NULL;
510 break;
511 }
512 state->idev = in6_dev_get(state->dev);
513 if (!state->idev)
514 continue;
515 read_lock_bh(&state->idev->lock);
516 im = state->idev->ac_list;
517 }
518 return im;
519 }
520
521 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
522 {
523 struct ifacaddr6 *im = ac6_get_first(seq);
524 if (im)
525 while (pos && (im = ac6_get_next(seq, im)) != NULL)
526 --pos;
527 return pos ? NULL : im;
528 }
529
530 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
531 {
532 read_lock(&dev_base_lock);
533 return ac6_get_idx(seq, *pos);
534 }
535
536 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
537 {
538 struct ifacaddr6 *im;
539 im = ac6_get_next(seq, v);
540 ++*pos;
541 return im;
542 }
543
544 static void ac6_seq_stop(struct seq_file *seq, void *v)
545 {
546 struct ac6_iter_state *state = ac6_seq_private(seq);
547 if (likely(state->idev != NULL)) {
548 read_unlock_bh(&state->idev->lock);
549 in6_dev_put(state->idev);
550 }
551 read_unlock(&dev_base_lock);
552 }
553
554 static int ac6_seq_show(struct seq_file *seq, void *v)
555 {
556 struct ifacaddr6 *im = (struct ifacaddr6 *)v;
557 struct ac6_iter_state *state = ac6_seq_private(seq);
558
559 seq_printf(seq,
560 "%-4d %-15s "
561 "%04x%04x%04x%04x%04x%04x%04x%04x "
562 "%5d\n",
563 state->dev->ifindex, state->dev->name,
564 NIP6(im->aca_addr),
565 im->aca_users);
566 return 0;
567 }
568
569 static struct seq_operations ac6_seq_ops = {
570 .start = ac6_seq_start,
571 .next = ac6_seq_next,
572 .stop = ac6_seq_stop,
573 .show = ac6_seq_show,
574 };
575
576 static int ac6_seq_open(struct inode *inode, struct file *file)
577 {
578 struct seq_file *seq;
579 int rc = -ENOMEM;
580 struct ac6_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
581
582 if (!s)
583 goto out;
584
585 rc = seq_open(file, &ac6_seq_ops);
586 if (rc)
587 goto out_kfree;
588
589 seq = file->private_data;
590 seq->private = s;
591 memset(s, 0, sizeof(*s));
592 out:
593 return rc;
594 out_kfree:
595 kfree(s);
596 goto out;
597 }
598
599 static struct file_operations ac6_seq_fops = {
600 .owner = THIS_MODULE,
601 .open = ac6_seq_open,
602 .read = seq_read,
603 .llseek = seq_lseek,
604 .release = seq_release_private,
605 };
606
607 int __init ac6_proc_init(void)
608 {
609 if (!proc_net_fops_create("anycast6", S_IRUGO, &ac6_seq_fops))
610 return -ENOMEM;
611
612 return 0;
613 }
614
615 void ac6_proc_exit(void)
616 {
617 proc_net_remove("anycast6");
618 }
619 #endif
620
621
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