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/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>
34 #include <net/net_namespace.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>
45 #include <net/checksum.h>
47 static int ipv6_dev_ac_dec(struct net_device
*dev
, const struct in6_addr
*addr
);
50 * socket join an anycast group
53 int ipv6_sock_ac_join(struct sock
*sk
, int ifindex
, const struct in6_addr
*addr
)
55 struct ipv6_pinfo
*np
= inet6_sk(sk
);
56 struct net_device
*dev
= NULL
;
57 struct inet6_dev
*idev
;
58 struct ipv6_ac_socklist
*pac
;
59 struct net
*net
= sock_net(sk
);
60 int ishost
= !net
->ipv6
.devconf_all
->forwarding
;
65 if (!ns_capable(net
->user_ns
, CAP_NET_ADMIN
))
67 if (ipv6_addr_is_multicast(addr
))
69 if (ipv6_chk_addr(net
, addr
, NULL
, 0))
72 pac
= sock_kmalloc(sk
, sizeof(struct ipv6_ac_socklist
), GFP_KERNEL
);
76 pac
->acl_addr
= *addr
;
81 rt
= rt6_lookup(net
, addr
, NULL
, 0, 0);
89 /* router, no matching interface: just pick one */
90 dev
= __dev_get_by_flags(net
, IFF_UP
,
91 IFF_UP
| IFF_LOOPBACK
);
94 dev
= __dev_get_by_index(net
, ifindex
);
101 idev
= __in6_dev_get(dev
);
106 err
= -EADDRNOTAVAIL
;
109 /* reset ishost, now that we have a specific device */
110 ishost
= !idev
->cnf
.forwarding
;
112 pac
->acl_ifindex
= dev
->ifindex
;
115 * For hosts, allow link-local or matching prefix anycasts.
116 * This obviates the need for propagating anycast routes while
117 * still allowing some non-router anycast participation.
119 if (!ipv6_chk_prefix(addr
, dev
)) {
121 err
= -EADDRNOTAVAIL
;
126 err
= __ipv6_dev_ac_inc(idev
, addr
);
128 pac
->acl_next
= np
->ipv6_ac_list
;
129 np
->ipv6_ac_list
= pac
;
135 sock_kfree_s(sk
, pac
, sizeof(*pac
));
140 * socket leave an anycast group
142 int ipv6_sock_ac_drop(struct sock
*sk
, int ifindex
, const struct in6_addr
*addr
)
144 struct ipv6_pinfo
*np
= inet6_sk(sk
);
145 struct net_device
*dev
;
146 struct ipv6_ac_socklist
*pac
, *prev_pac
;
147 struct net
*net
= sock_net(sk
);
152 for (pac
= np
->ipv6_ac_list
; pac
; pac
= pac
->acl_next
) {
153 if ((ifindex
== 0 || pac
->acl_ifindex
== ifindex
) &&
154 ipv6_addr_equal(&pac
->acl_addr
, addr
))
161 prev_pac
->acl_next
= pac
->acl_next
;
163 np
->ipv6_ac_list
= pac
->acl_next
;
165 dev
= __dev_get_by_index(net
, pac
->acl_ifindex
);
167 ipv6_dev_ac_dec(dev
, &pac
->acl_addr
);
169 sock_kfree_s(sk
, pac
, sizeof(*pac
));
173 void ipv6_sock_ac_close(struct sock
*sk
)
175 struct ipv6_pinfo
*np
= inet6_sk(sk
);
176 struct net_device
*dev
= NULL
;
177 struct ipv6_ac_socklist
*pac
;
178 struct net
*net
= sock_net(sk
);
181 if (!np
->ipv6_ac_list
)
185 pac
= np
->ipv6_ac_list
;
186 np
->ipv6_ac_list
= NULL
;
190 struct ipv6_ac_socklist
*next
= pac
->acl_next
;
192 if (pac
->acl_ifindex
!= prev_index
) {
193 dev
= __dev_get_by_index(net
, pac
->acl_ifindex
);
194 prev_index
= pac
->acl_ifindex
;
197 ipv6_dev_ac_dec(dev
, &pac
->acl_addr
);
198 sock_kfree_s(sk
, pac
, sizeof(*pac
));
204 static void aca_get(struct ifacaddr6
*aca
)
206 refcount_inc(&aca
->aca_refcnt
);
209 static void aca_put(struct ifacaddr6
*ac
)
211 if (refcount_dec_and_test(&ac
->aca_refcnt
)) {
212 in6_dev_put(ac
->aca_idev
);
213 dst_release(&ac
->aca_rt
->dst
);
218 static struct ifacaddr6
*aca_alloc(struct rt6_info
*rt
,
219 const struct in6_addr
*addr
)
221 struct inet6_dev
*idev
= rt
->rt6i_idev
;
222 struct ifacaddr6
*aca
;
224 aca
= kzalloc(sizeof(*aca
), GFP_ATOMIC
);
228 aca
->aca_addr
= *addr
;
230 aca
->aca_idev
= idev
;
233 /* aca_tstamp should be updated upon changes */
234 aca
->aca_cstamp
= aca
->aca_tstamp
= jiffies
;
235 refcount_set(&aca
->aca_refcnt
, 1);
241 * device anycast group inc (add if not found)
243 int __ipv6_dev_ac_inc(struct inet6_dev
*idev
, const struct in6_addr
*addr
)
245 struct ifacaddr6
*aca
;
251 write_lock_bh(&idev
->lock
);
257 for (aca
= idev
->ac_list
; aca
; aca
= aca
->aca_next
) {
258 if (ipv6_addr_equal(&aca
->aca_addr
, addr
)) {
265 rt
= addrconf_dst_alloc(idev
, addr
, true);
270 aca
= aca_alloc(rt
, addr
);
277 aca
->aca_next
= idev
->ac_list
;
280 /* Hold this for addrconf_join_solict() below before we unlock,
281 * it is already exposed via idev->ac_list.
284 write_unlock_bh(&idev
->lock
);
288 addrconf_join_solict(idev
->dev
, &aca
->aca_addr
);
293 write_unlock_bh(&idev
->lock
);
298 * device anycast group decrement
300 int __ipv6_dev_ac_dec(struct inet6_dev
*idev
, const struct in6_addr
*addr
)
302 struct ifacaddr6
*aca
, *prev_aca
;
306 write_lock_bh(&idev
->lock
);
308 for (aca
= idev
->ac_list
; aca
; aca
= aca
->aca_next
) {
309 if (ipv6_addr_equal(&aca
->aca_addr
, addr
))
314 write_unlock_bh(&idev
->lock
);
317 if (--aca
->aca_users
> 0) {
318 write_unlock_bh(&idev
->lock
);
322 prev_aca
->aca_next
= aca
->aca_next
;
324 idev
->ac_list
= aca
->aca_next
;
325 write_unlock_bh(&idev
->lock
);
326 addrconf_leave_solict(idev
, &aca
->aca_addr
);
328 dst_hold(&aca
->aca_rt
->dst
);
329 ip6_del_rt(aca
->aca_rt
);
335 /* called with rtnl_lock() */
336 static int ipv6_dev_ac_dec(struct net_device
*dev
, const struct in6_addr
*addr
)
338 struct inet6_dev
*idev
= __in6_dev_get(dev
);
342 return __ipv6_dev_ac_dec(idev
, addr
);
345 void ipv6_ac_destroy_dev(struct inet6_dev
*idev
)
347 struct ifacaddr6
*aca
;
349 write_lock_bh(&idev
->lock
);
350 while ((aca
= idev
->ac_list
) != NULL
) {
351 idev
->ac_list
= aca
->aca_next
;
352 write_unlock_bh(&idev
->lock
);
354 addrconf_leave_solict(idev
, &aca
->aca_addr
);
356 dst_hold(&aca
->aca_rt
->dst
);
357 ip6_del_rt(aca
->aca_rt
);
361 write_lock_bh(&idev
->lock
);
363 write_unlock_bh(&idev
->lock
);
367 * check if the interface has this anycast address
368 * called with rcu_read_lock()
370 static bool ipv6_chk_acast_dev(struct net_device
*dev
, const struct in6_addr
*addr
)
372 struct inet6_dev
*idev
;
373 struct ifacaddr6
*aca
;
375 idev
= __in6_dev_get(dev
);
377 read_lock_bh(&idev
->lock
);
378 for (aca
= idev
->ac_list
; aca
; aca
= aca
->aca_next
)
379 if (ipv6_addr_equal(&aca
->aca_addr
, addr
))
381 read_unlock_bh(&idev
->lock
);
388 * check if given interface (or any, if dev==0) has this anycast address
390 bool ipv6_chk_acast_addr(struct net
*net
, struct net_device
*dev
,
391 const struct in6_addr
*addr
)
397 found
= ipv6_chk_acast_dev(dev
, addr
);
399 for_each_netdev_rcu(net
, dev
)
400 if (ipv6_chk_acast_dev(dev
, addr
)) {
408 /* check if this anycast address is link-local on given interface or
411 bool ipv6_chk_acast_addr_src(struct net
*net
, struct net_device
*dev
,
412 const struct in6_addr
*addr
)
414 return ipv6_chk_acast_addr(net
,
415 (ipv6_addr_type(addr
) & IPV6_ADDR_LINKLOCAL
?
420 #ifdef CONFIG_PROC_FS
421 struct ac6_iter_state
{
422 struct seq_net_private p
;
423 struct net_device
*dev
;
424 struct inet6_dev
*idev
;
427 #define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private)
429 static inline struct ifacaddr6
*ac6_get_first(struct seq_file
*seq
)
431 struct ifacaddr6
*im
= NULL
;
432 struct ac6_iter_state
*state
= ac6_seq_private(seq
);
433 struct net
*net
= seq_file_net(seq
);
436 for_each_netdev_rcu(net
, state
->dev
) {
437 struct inet6_dev
*idev
;
438 idev
= __in6_dev_get(state
->dev
);
441 read_lock_bh(&idev
->lock
);
447 read_unlock_bh(&idev
->lock
);
452 static struct ifacaddr6
*ac6_get_next(struct seq_file
*seq
, struct ifacaddr6
*im
)
454 struct ac6_iter_state
*state
= ac6_seq_private(seq
);
458 if (likely(state
->idev
!= NULL
))
459 read_unlock_bh(&state
->idev
->lock
);
461 state
->dev
= next_net_device_rcu(state
->dev
);
466 state
->idev
= __in6_dev_get(state
->dev
);
469 read_lock_bh(&state
->idev
->lock
);
470 im
= state
->idev
->ac_list
;
475 static struct ifacaddr6
*ac6_get_idx(struct seq_file
*seq
, loff_t pos
)
477 struct ifacaddr6
*im
= ac6_get_first(seq
);
479 while (pos
&& (im
= ac6_get_next(seq
, im
)) != NULL
)
481 return pos
? NULL
: im
;
484 static void *ac6_seq_start(struct seq_file
*seq
, loff_t
*pos
)
488 return ac6_get_idx(seq
, *pos
);
491 static void *ac6_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
493 struct ifacaddr6
*im
= ac6_get_next(seq
, v
);
499 static void ac6_seq_stop(struct seq_file
*seq
, void *v
)
502 struct ac6_iter_state
*state
= ac6_seq_private(seq
);
504 if (likely(state
->idev
!= NULL
)) {
505 read_unlock_bh(&state
->idev
->lock
);
511 static int ac6_seq_show(struct seq_file
*seq
, void *v
)
513 struct ifacaddr6
*im
= (struct ifacaddr6
*)v
;
514 struct ac6_iter_state
*state
= ac6_seq_private(seq
);
516 seq_printf(seq
, "%-4d %-15s %pi6 %5d\n",
517 state
->dev
->ifindex
, state
->dev
->name
,
518 &im
->aca_addr
, im
->aca_users
);
522 static const struct seq_operations ac6_seq_ops
= {
523 .start
= ac6_seq_start
,
524 .next
= ac6_seq_next
,
525 .stop
= ac6_seq_stop
,
526 .show
= ac6_seq_show
,
529 static int ac6_seq_open(struct inode
*inode
, struct file
*file
)
531 return seq_open_net(inode
, file
, &ac6_seq_ops
,
532 sizeof(struct ac6_iter_state
));
535 static const struct file_operations ac6_seq_fops
= {
536 .owner
= THIS_MODULE
,
537 .open
= ac6_seq_open
,
540 .release
= seq_release_net
,
543 int __net_init
ac6_proc_init(struct net
*net
)
545 if (!proc_create("anycast6", S_IRUGO
, net
->proc_net
, &ac6_seq_fops
))
551 void ac6_proc_exit(struct net
*net
)
553 remove_proc_entry("anycast6", net
->proc_net
);