2 * Anycast support for IPv6
3 * Linux INET6 implementation
6 * David L Stevens (dlstevens@us.ibm.com)
8 * based heavily on net/ipv6/mcast.c
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.
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>
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>
44 #include <net/checksum.h>
46 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr);
48 /* Big ac list lock for all the sockets */
49 static DEFINE_RWLOCK(ipv6_sk_ac_lock);
51 /* XXX ip6_addr_match() and ip6_onlink() really belong in net/core.c */
54 ip6_addr_match(struct in6_addr *addr1, struct in6_addr *addr2, int prefix)
59 if (prefix > 128 || prefix < 0)
67 mask = htonl(~0 << (32 - prefix));
68 if ((addr1->s6_addr32[i] ^ addr2->s6_addr32[i]) & mask)
78 ip6_onlink(struct in6_addr *addr, struct net_device *dev)
80 struct inet6_dev *idev;
81 struct inet6_ifaddr *ifa;
85 read_lock(&addrconf_lock);
86 idev = __in6_dev_get(dev);
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,
95 read_unlock_bh(&idev->lock);
97 read_unlock(&addrconf_lock);
102 * socket join an anycast group
105 int ipv6_sock_ac_join(struct sock *sk, int ifindex, struct in6_addr *addr)
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;
114 if (!capable(CAP_NET_ADMIN))
116 if (ipv6_addr_is_multicast(addr))
118 if (ipv6_chk_addr(addr, NULL, 0))
121 pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
124 pac->acl_next = NULL;
125 ipv6_addr_copy(&pac->acl_addr, addr);
130 rt = rt6_lookup(addr, NULL, 0, 0);
134 dst_release(&rt->u.dst);
136 err = -EADDRNOTAVAIL;
139 /* router, no matching interface: just pick one */
141 dev = dev_get_by_flags(IFF_UP, IFF_UP|IFF_LOOPBACK);
144 dev = dev_get_by_index(ifindex);
151 idev = in6_dev_get(dev);
156 err = -EADDRNOTAVAIL;
159 /* reset ishost, now that we have a specific device */
160 ishost = !idev->cnf.forwarding;
163 pac->acl_ifindex = dev->ifindex;
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.
170 if (!ip6_onlink(addr, dev)) {
172 err = -EADDRNOTAVAIL;
177 err = ipv6_dev_ac_inc(dev, addr);
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);
193 sock_kfree_s(sk, pac, sizeof(*pac));
198 * socket leave an anycast group
200 int ipv6_sock_ac_drop(struct sock *sk, int ifindex, struct in6_addr *addr)
202 struct ipv6_pinfo *np = inet6_sk(sk);
203 struct net_device *dev;
204 struct ipv6_ac_socklist *pac, *prev_pac;
206 write_lock_bh(&ipv6_sk_ac_lock);
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))
215 write_unlock_bh(&ipv6_sk_ac_lock);
219 prev_pac->acl_next = pac->acl_next;
221 np->ipv6_ac_list = pac->acl_next;
223 write_unlock_bh(&ipv6_sk_ac_lock);
225 dev = dev_get_by_index(pac->acl_ifindex);
227 ipv6_dev_ac_dec(dev, &pac->acl_addr);
230 sock_kfree_s(sk, pac, sizeof(*pac));
234 void ipv6_sock_ac_close(struct sock *sk)
236 struct ipv6_pinfo *np = inet6_sk(sk);
237 struct net_device *dev = NULL;
238 struct ipv6_ac_socklist *pac;
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);
248 struct ipv6_ac_socklist *next = pac->acl_next;
250 if (pac->acl_ifindex != prev_index) {
253 dev = dev_get_by_index(pac->acl_ifindex);
254 prev_index = pac->acl_ifindex;
257 ipv6_dev_ac_dec(dev, &pac->acl_addr);
258 sock_kfree_s(sk, pac, sizeof(*pac));
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.
269 * It is OK, anycasts are not special comparing to delivery to unicasts.
272 int inet6_ac_check(struct sock *sk, struct in6_addr *addr, int ifindex)
274 struct ipv6_ac_socklist *pac;
275 struct ipv6_pinfo *np = inet6_sk(sk);
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)
283 found = ipv6_addr_equal(&pac->acl_addr, addr);
287 read_unlock(&ipv6_sk_ac_lock);
294 static void aca_put(struct ifacaddr6 *ac)
296 if (atomic_dec_and_test(&ac->aca_refcnt)) {
297 in6_dev_put(ac->aca_idev);
298 dst_release(&ac->aca_rt->u.dst);
304 * device anycast group inc (add if not found)
306 int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr)
308 struct ifacaddr6 *aca;
309 struct inet6_dev *idev;
313 idev = in6_dev_get(dev);
318 write_lock_bh(&idev->lock);
324 for (aca = idev->ac_list; aca; aca = aca->aca_next) {
325 if (ipv6_addr_equal(&aca->aca_addr, addr)) {
333 * not found: create a new one.
336 aca = kmalloc(sizeof(struct ifacaddr6), GFP_ATOMIC);
343 rt = addrconf_dst_alloc(idev, addr, 1);
350 memset(aca, 0, sizeof(struct ifacaddr6));
352 ipv6_addr_copy(&aca->aca_addr, addr);
353 aca->aca_idev = idev;
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);
361 aca->aca_next = idev->ac_list;
363 write_unlock_bh(&idev->lock);
365 dst_hold(&rt->u.dst);
366 if (ip6_ins_rt(rt, NULL, NULL))
367 dst_release(&rt->u.dst);
369 addrconf_join_solict(dev, &aca->aca_addr);
374 write_unlock_bh(&idev->lock);
380 * device anycast group decrement
382 int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr)
384 struct ifacaddr6 *aca, *prev_aca;
386 write_lock_bh(&idev->lock);
388 for (aca = idev->ac_list; aca; aca = aca->aca_next) {
389 if (ipv6_addr_equal(&aca->aca_addr, addr))
394 write_unlock_bh(&idev->lock);
397 if (--aca->aca_users > 0) {
398 write_unlock_bh(&idev->lock);
402 prev_aca->aca_next = aca->aca_next;
404 idev->ac_list = aca->aca_next;
405 write_unlock_bh(&idev->lock);
406 addrconf_leave_solict(idev, &aca->aca_addr);
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);
412 dst_release(&aca->aca_rt->u.dst);
418 static int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
421 struct inet6_dev *idev = in6_dev_get(dev);
424 ret = __ipv6_dev_ac_dec(idev, addr);
430 * check if the interface has this anycast address
432 static int ipv6_chk_acast_dev(struct net_device *dev, struct in6_addr *addr)
434 struct inet6_dev *idev;
435 struct ifacaddr6 *aca;
437 idev = in6_dev_get(dev);
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))
443 read_unlock_bh(&idev->lock);
451 * check if given interface (or any, if dev==0) has this anycast address
453 int ipv6_chk_acast_addr(struct net_device *dev, struct in6_addr *addr)
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))
461 read_unlock(&dev_base_lock);
466 #ifdef CONFIG_PROC_FS
467 struct ac6_iter_state {
468 struct net_device *dev;
469 struct inet6_dev *idev;
472 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private)
474 static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
476 struct ifacaddr6 *im = NULL;
477 struct ac6_iter_state *state = ac6_seq_private(seq);
479 for (state->dev = dev_base, state->idev = NULL;
481 state->dev = state->dev->next) {
482 struct inet6_dev *idev;
483 idev = in6_dev_get(state->dev);
486 read_lock_bh(&idev->lock);
492 read_unlock_bh(&idev->lock);
497 static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im)
499 struct ac6_iter_state *state = ac6_seq_private(seq);
503 if (likely(state->idev != NULL)) {
504 read_unlock_bh(&state->idev->lock);
505 in6_dev_put(state->idev);
507 state->dev = state->dev->next;
512 state->idev = in6_dev_get(state->dev);
515 read_lock_bh(&state->idev->lock);
516 im = state->idev->ac_list;
521 static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
523 struct ifacaddr6 *im = ac6_get_first(seq);
525 while (pos && (im = ac6_get_next(seq, im)) != NULL)
527 return pos ? NULL : im;
530 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
532 read_lock(&dev_base_lock);
533 return ac6_get_idx(seq, *pos);
536 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
538 struct ifacaddr6 *im;
539 im = ac6_get_next(seq, v);
544 static void ac6_seq_stop(struct seq_file *seq, void *v)
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);
551 read_unlock(&dev_base_lock);
554 static int ac6_seq_show(struct seq_file *seq, void *v)
556 struct ifacaddr6 *im = (struct ifacaddr6 *)v;
557 struct ac6_iter_state *state = ac6_seq_private(seq);
561 "%04x%04x%04x%04x%04x%04x%04x%04x "
563 state->dev->ifindex, state->dev->name,
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,
576 static int ac6_seq_open(struct inode *inode, struct file *file)
578 struct seq_file *seq;
580 struct ac6_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
585 rc = seq_open(file, &ac6_seq_ops);
589 seq = file->private_data;
591 memset(s, 0, sizeof(*s));
599 static struct file_operations ac6_seq_fops = {
600 .owner = THIS_MODULE,
601 .open = ac6_seq_open,
604 .release = seq_release_private,
607 int __init ac6_proc_init(void)
609 if (!proc_net_fops_create("anycast6", S_IRUGO, &ac6_seq_fops))
615 void ac6_proc_exit(void)
617 proc_net_remove("anycast6");