[deliverable/linux.git] / net / ipv6 / anycast.c

/*
 *	Anycast support for IPv6
 *	Linux INET6 implementation
 *
 *	Authors:
 *	David L Stevens (dlstevens@us.ibm.com)
 *
 *	based heavily on net/ipv6/mcast.c
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/random.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/route.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/snmp.h>

#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/if_inet6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>

#include <net/checksum.h>

static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr);

/*
 *	socket join an anycast group
 */

int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct net_device *dev = NULL;
	struct inet6_dev *idev;
	struct ipv6_ac_socklist *pac;
	struct net *net = sock_net(sk);
	int	ishost = !net->ipv6.devconf_all->forwarding;
	int	err = 0;

	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
		return -EPERM;
	if (ipv6_addr_is_multicast(addr))
		return -EINVAL;
	if (ipv6_chk_addr(net, addr, NULL, 0))
		return -EINVAL;

	pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
	if (pac == NULL)
		return -ENOMEM;
	pac->acl_next = NULL;
	pac->acl_addr = *addr;

	rtnl_lock();
	if (ifindex == 0) {
		struct rt6_info *rt;

		rt = rt6_lookup(net, addr, NULL, 0, 0);
		if (rt) {
			dev = rt->dst.dev;
			ip6_rt_put(rt);
		} else if (ishost) {
			err = -EADDRNOTAVAIL;
			goto error;
		} else {
			/* router, no matching interface: just pick one */
			dev = __dev_get_by_flags(net, IFF_UP,
						 IFF_UP | IFF_LOOPBACK);
		}
	} else
		dev = __dev_get_by_index(net, ifindex);

	if (dev == NULL) {
		err = -ENODEV;
		goto error;
	}

	idev = __in6_dev_get(dev);
	if (!idev) {
		if (ifindex)
			err = -ENODEV;
		else
			err = -EADDRNOTAVAIL;
		goto error;
	}
	/* reset ishost, now that we have a specific device */
	ishost = !idev->cnf.forwarding;

	pac->acl_ifindex = dev->ifindex;

	/* XXX
	 * For hosts, allow link-local or matching prefix anycasts.
	 * This obviates the need for propagating anycast routes while
	 * still allowing some non-router anycast participation.
	 */
	if (!ipv6_chk_prefix(addr, dev)) {
		if (ishost)
			err = -EADDRNOTAVAIL;
		if (err)
			goto error;
	}

	err = __ipv6_dev_ac_inc(idev, addr);
	if (!err) {
		pac->acl_next = np->ipv6_ac_list;
		np->ipv6_ac_list = pac;
		pac = NULL;
	}

error:
	rtnl_unlock();
	if (pac)
		sock_kfree_s(sk, pac, sizeof(*pac));
	return err;
}

/*
 *	socket leave an anycast group
 */
int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct net_device *dev;
	struct ipv6_ac_socklist *pac, *prev_pac;
	struct net *net = sock_net(sk);

	rtnl_lock();
	prev_pac = NULL;
	for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
		if ((ifindex == 0 || pac->acl_ifindex == ifindex) &&
		     ipv6_addr_equal(&pac->acl_addr, addr))
			break;
		prev_pac = pac;
	}
	if (!pac) {
		rtnl_unlock();
		return -ENOENT;
	}
	if (prev_pac)
		prev_pac->acl_next = pac->acl_next;
	else
		np->ipv6_ac_list = pac->acl_next;

	dev = __dev_get_by_index(net, pac->acl_ifindex);
	if (dev)
		ipv6_dev_ac_dec(dev, &pac->acl_addr);
	rtnl_unlock();

	sock_kfree_s(sk, pac, sizeof(*pac));
	return 0;
}

void ipv6_sock_ac_close(struct sock *sk)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct net_device *dev = NULL;
	struct ipv6_ac_socklist *pac;
	struct net *net = sock_net(sk);
	int	prev_index;

	if (!np->ipv6_ac_list)
		return;

	rtnl_lock();
	pac = np->ipv6_ac_list;
	np->ipv6_ac_list = NULL;

	prev_index = 0;
	while (pac) {
		struct ipv6_ac_socklist *next = pac->acl_next;

		if (pac->acl_ifindex != prev_index) {
			dev = __dev_get_by_index(net, pac->acl_ifindex);
			prev_index = pac->acl_ifindex;
		}
		if (dev)
			ipv6_dev_ac_dec(dev, &pac->acl_addr);
		sock_kfree_s(sk, pac, sizeof(*pac));
		pac = next;
	}
	rtnl_unlock();
}

static void aca_get(struct ifacaddr6 *aca)
{
	atomic_inc(&aca->aca_refcnt);
}

static void aca_put(struct ifacaddr6 *ac)
{
	if (atomic_dec_and_test(&ac->aca_refcnt)) {
		in6_dev_put(ac->aca_idev);
		dst_release(&ac->aca_rt->dst);
		kfree(ac);
	}
}

static struct ifacaddr6 *aca_alloc(struct rt6_info *rt,
				   const struct in6_addr *addr)
{
	struct inet6_dev *idev = rt->rt6i_idev;
	struct ifacaddr6 *aca;

	aca = kzalloc(sizeof(*aca), GFP_ATOMIC);
	if (aca == NULL)
		return NULL;

	aca->aca_addr = *addr;
	in6_dev_hold(idev);
	aca->aca_idev = idev;
	aca->aca_rt = rt;
	aca->aca_users = 1;
	/* aca_tstamp should be updated upon changes */
	aca->aca_cstamp = aca->aca_tstamp = jiffies;
	atomic_set(&aca->aca_refcnt, 1);

	return aca;
}

/*
 *	device anycast group inc (add if not found)
 */
int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
{
	struct ifacaddr6 *aca;
	struct rt6_info *rt;
	int err;

	ASSERT_RTNL();

	write_lock_bh(&idev->lock);
	if (idev->dead) {
		err = -ENODEV;
		goto out;
	}

	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
		if (ipv6_addr_equal(&aca->aca_addr, addr)) {
			aca->aca_users++;
			err = 0;
			goto out;
		}
	}

	rt = addrconf_dst_alloc(idev, addr, true);
	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		goto out;
	}
	aca = aca_alloc(rt, addr);
	if (aca == NULL) {
		ip6_rt_put(rt);
		err = -ENOMEM;
		goto out;
	}

	aca->aca_next = idev->ac_list;
	idev->ac_list = aca;

	/* Hold this for addrconf_join_solict() below before we unlock,
	 * it is already exposed via idev->ac_list.
	 */
	aca_get(aca);
	write_unlock_bh(&idev->lock);

	ip6_ins_rt(rt);

	addrconf_join_solict(idev->dev, &aca->aca_addr);

	aca_put(aca);
	return 0;
out:
	write_unlock_bh(&idev->lock);
	return err;
}

/*
 *	device anycast group decrement
 */
int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
{
	struct ifacaddr6 *aca, *prev_aca;

	ASSERT_RTNL();

	write_lock_bh(&idev->lock);
	prev_aca = NULL;
	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
		if (ipv6_addr_equal(&aca->aca_addr, addr))
			break;
		prev_aca = aca;
	}
	if (!aca) {
		write_unlock_bh(&idev->lock);
		return -ENOENT;
	}
	if (--aca->aca_users > 0) {
		write_unlock_bh(&idev->lock);
		return 0;
	}
	if (prev_aca)
		prev_aca->aca_next = aca->aca_next;
	else
		idev->ac_list = aca->aca_next;
	write_unlock_bh(&idev->lock);
	addrconf_leave_solict(idev, &aca->aca_addr);

	dst_hold(&aca->aca_rt->dst);
	ip6_del_rt(aca->aca_rt);

	aca_put(aca);
	return 0;
}

/* called with rtnl_lock() */
static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr)
{
	struct inet6_dev *idev = __in6_dev_get(dev);

	if (idev == NULL)
		return -ENODEV;
	return __ipv6_dev_ac_dec(idev, addr);
}

void ipv6_ac_destroy_dev(struct inet6_dev *idev)
{
	struct ifacaddr6 *aca;

	write_lock_bh(&idev->lock);
	while ((aca = idev->ac_list) != NULL) {
		idev->ac_list = aca->aca_next;
		write_unlock_bh(&idev->lock);

		addrconf_leave_solict(idev, &aca->aca_addr);

		dst_hold(&aca->aca_rt->dst);
		ip6_del_rt(aca->aca_rt);

		aca_put(aca);

		write_lock_bh(&idev->lock);
	}
	write_unlock_bh(&idev->lock);
}

/*
 *	check if the interface has this anycast address
 *	called with rcu_read_lock()
 */
static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr)
{
	struct inet6_dev *idev;
	struct ifacaddr6 *aca;

	idev = __in6_dev_get(dev);
	if (idev) {
		read_lock_bh(&idev->lock);
		for (aca = idev->ac_list; aca; aca = aca->aca_next)
			if (ipv6_addr_equal(&aca->aca_addr, addr))
				break;
		read_unlock_bh(&idev->lock);
		return aca != NULL;
	}
	return false;
}

/*
 *	check if given interface (or any, if dev==0) has this anycast address
 */
bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev,
			 const struct in6_addr *addr)
{
	bool found = false;

	rcu_read_lock();
	if (dev)
		found = ipv6_chk_acast_dev(dev, addr);
	else
		for_each_netdev_rcu(net, dev)
			if (ipv6_chk_acast_dev(dev, addr)) {
				found = true;
				break;
			}
	rcu_read_unlock();
	return found;
}

/*	check if this anycast address is link-local on given interface or
 *	is global
 */
bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev,
			     const struct in6_addr *addr)
{
	return ipv6_chk_acast_addr(net,
				   (ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ?
				    dev : NULL),
				   addr);
}

#ifdef CONFIG_PROC_FS
struct ac6_iter_state {
	struct seq_net_private p;
	struct net_device *dev;
	struct inet6_dev *idev;
};

#define ac6_seq_private(seq)	((struct ac6_iter_state *)(seq)->private)

static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
{
	struct ifacaddr6 *im = NULL;
	struct ac6_iter_state *state = ac6_seq_private(seq);
	struct net *net = seq_file_net(seq);

	state->idev = NULL;
	for_each_netdev_rcu(net, state->dev) {
		struct inet6_dev *idev;
		idev = __in6_dev_get(state->dev);
		if (!idev)
			continue;
		read_lock_bh(&idev->lock);
		im = idev->ac_list;
		if (im) {
			state->idev = idev;
			break;
		}
		read_unlock_bh(&idev->lock);
	}
	return im;
}

static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im)
{
	struct ac6_iter_state *state = ac6_seq_private(seq);

	im = im->aca_next;
	while (!im) {
		if (likely(state->idev != NULL))
			read_unlock_bh(&state->idev->lock);

		state->dev = next_net_device_rcu(state->dev);
		if (!state->dev) {
			state->idev = NULL;
			break;
		}
		state->idev = __in6_dev_get(state->dev);
		if (!state->idev)
			continue;
		read_lock_bh(&state->idev->lock);
		im = state->idev->ac_list;
	}
	return im;
}

static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
{
	struct ifacaddr6 *im = ac6_get_first(seq);
	if (im)
		while (pos && (im = ac6_get_next(seq, im)) != NULL)
			--pos;
	return pos ? NULL : im;
}

static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(RCU)
{
	rcu_read_lock();
	return ac6_get_idx(seq, *pos);
}

static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct ifacaddr6 *im = ac6_get_next(seq, v);

	++*pos;
	return im;
}

static void ac6_seq_stop(struct seq_file *seq, void *v)
	__releases(RCU)
{
	struct ac6_iter_state *state = ac6_seq_private(seq);

	if (likely(state->idev != NULL)) {
		read_unlock_bh(&state->idev->lock);
		state->idev = NULL;
	}
	rcu_read_unlock();
}

static int ac6_seq_show(struct seq_file *seq, void *v)
{
	struct ifacaddr6 *im = (struct ifacaddr6 *)v;
	struct ac6_iter_state *state = ac6_seq_private(seq);

	seq_printf(seq, "%-4d %-15s %pi6 %5d\n",
		   state->dev->ifindex, state->dev->name,
		   &im->aca_addr, im->aca_users);
	return 0;
}

static const struct seq_operations ac6_seq_ops = {
	.start	=	ac6_seq_start,
	.next	=	ac6_seq_next,
	.stop	=	ac6_seq_stop,
	.show	=	ac6_seq_show,
};

static int ac6_seq_open(struct inode *inode, struct file *file)
{
	return seq_open_net(inode, file, &ac6_seq_ops,
			    sizeof(struct ac6_iter_state));
}

static const struct file_operations ac6_seq_fops = {
	.owner		=	THIS_MODULE,
	.open		=	ac6_seq_open,
	.read		=	seq_read,
	.llseek		=	seq_lseek,
	.release	=	seq_release_net,
};

int __net_init ac6_proc_init(struct net *net)
{
	if (!proc_create("anycast6", S_IRUGO, net->proc_net, &ac6_seq_fops))
		return -ENOMEM;

	return 0;
}

void ac6_proc_exit(struct net *net)
{
	remove_proc_entry("anycast6", net->proc_net);
}
#endif
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* Anycast support for IPv6
1ab1457c	3	* Linux INET6 implementation
1da177e4 LT	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
4fc268d2	16	#include <linux/capability.h>
1da177e4 LT	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>
1da177e4 LT	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>
5a0e3ad6	32	#include <linux/slab.h>
1da177e4	33
457c4cbc	34	#include <net/net_namespace.h>
1da177e4 LT	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
b71d1d42	47	static int ipv6_dev_ac_dec(struct net_device dev, const struct in6_addr addr);
1da177e4	48
1da177e4 LT	49	/*
	50	* socket join an anycast group
	51	*/
	52
b71d1d42	53	int ipv6_sock_ac_join(struct sock sk, int ifindex, const struct in6_addr addr)
1da177e4 LT	54	{
	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;
6ab57e7e	59	struct net *net = sock_net(sk);
53b7997f	60	int ishost = !net->ipv6.devconf_all->forwarding;
1da177e4 LT	61	int err = 0;
1da177e4 LT	62
af31f412	63	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1da177e4 LT	64	return -EPERM;
	65	if (ipv6_addr_is_multicast(addr))
	66	return -EINVAL;
6ab57e7e	67	if (ipv6_chk_addr(net, addr, NULL, 0))
1da177e4 LT	68	return -EINVAL;
	69
	70	pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
	71	if (pac == NULL)
	72	return -ENOMEM;
	73	pac->acl_next = NULL;
4e3fd7a0	74	pac->acl_addr = *addr;
1da177e4	75
a9ed4a29	76	rtnl_lock();
1da177e4 LT	77	if (ifindex == 0) {
	78	struct rt6_info *rt;
	79
6ab57e7e	80	rt = rt6_lookup(net, addr, NULL, 0, 0);
1da177e4	81	if (rt) {
d1918542	82	dev = rt->dst.dev;
94e187c0	83	ip6_rt_put(rt);
1da177e4 LT	84	} else if (ishost) {
1da177e4 LT	85	err = -EADDRNOTAVAIL;
bb69ae04	86	goto error;
1da177e4 LT	87	} else {
1da177e4 LT	88	/* router, no matching interface: just pick one */
6c555490 WC	89	dev = __dev_get_by_flags(net, IFF_UP,
6c555490 WC	90	IFF_UP \| IFF_LOOPBACK);
1da177e4 LT	91	}
1da177e4 LT	92	} else
6c555490	93	dev = __dev_get_by_index(net, ifindex);
1da177e4 LT	94
	95	if (dev == NULL) {
	96	err = -ENODEV;
bb69ae04	97	goto error;
1da177e4 LT	98	}
1da177e4 LT	99
bb69ae04	100	idev = __in6_dev_get(dev);
1da177e4 LT	101	if (!idev) {
	102	if (ifindex)
	103	err = -ENODEV;
	104	else
	105	err = -EADDRNOTAVAIL;
bb69ae04	106	goto error;
1da177e4 LT	107	}
	108	/* reset ishost, now that we have a specific device */
	109	ishost = !idev->cnf.forwarding;
1da177e4 LT	110
	111	pac->acl_ifindex = dev->ifindex;
	112
	113	/* XXX
	114	* For hosts, allow link-local or matching prefix anycasts.
	115	* This obviates the need for propagating anycast routes while
	116	* still allowing some non-router anycast participation.
	117	*/
52eeeb84	118	if (!ipv6_chk_prefix(addr, dev)) {
1da177e4 LT	119	if (ishost)
	120	err = -EADDRNOTAVAIL;
	121	if (err)
bb69ae04	122	goto error;
1da177e4 LT	123	}
1da177e4 LT	124
013b4d90	125	err = __ipv6_dev_ac_inc(idev, addr);
bb69ae04	126	if (!err) {
bb69ae04 ED	127	pac->acl_next = np->ipv6_ac_list;
bb69ae04 ED	128	np->ipv6_ac_list = pac;
bb69ae04 ED	129	pac = NULL;
bb69ae04 ED	130	}
1da177e4	131
bb69ae04	132	error:
a9ed4a29	133	rtnl_unlock();
bb69ae04 ED	134	if (pac)
bb69ae04 ED	135	sock_kfree_s(sk, pac, sizeof(*pac));
1da177e4 LT	136	return err;
	137	}
	138
	139	/*
	140	* socket leave an anycast group
	141	*/
b71d1d42	142	int ipv6_sock_ac_drop(struct sock sk, int ifindex, const struct in6_addr addr)
1da177e4 LT	143	{
	144	struct ipv6_pinfo *np = inet6_sk(sk);
	145	struct net_device *dev;
	146	struct ipv6_ac_socklist pac, prev_pac;
6ab57e7e	147	struct net *net = sock_net(sk);
1da177e4	148
b03a9c04	149	rtnl_lock();
1da177e4 LT	150	prev_pac = NULL;
	151	for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
	152	if ((ifindex == 0 \|\| pac->acl_ifindex == ifindex) &&
	153	ipv6_addr_equal(&pac->acl_addr, addr))
	154	break;
	155	prev_pac = pac;
	156	}
	157	if (!pac) {
b03a9c04	158	rtnl_unlock();
1da177e4 LT	159	return -ENOENT;
	160	}
	161	if (prev_pac)
	162	prev_pac->acl_next = pac->acl_next;
	163	else
	164	np->ipv6_ac_list = pac->acl_next;
	165
6c555490	166	dev = __dev_get_by_index(net, pac->acl_ifindex);
bb69ae04	167	if (dev)
1da177e4	168	ipv6_dev_ac_dec(dev, &pac->acl_addr);
a9ed4a29	169	rtnl_unlock();
bb69ae04	170
1da177e4 LT	171	sock_kfree_s(sk, pac, sizeof(*pac));
	172	return 0;
	173	}
	174
	175	void ipv6_sock_ac_close(struct sock *sk)
	176	{
	177	struct ipv6_pinfo *np = inet6_sk(sk);
	178	struct net_device *dev = NULL;
	179	struct ipv6_ac_socklist *pac;
6ab57e7e	180	struct net *net = sock_net(sk);
1da177e4 LT	181	int prev_index;
1da177e4 LT	182
0e1efe9d ED	183	if (!np->ipv6_ac_list)
	184	return;
	185
b03a9c04	186	rtnl_lock();
1da177e4 LT	187	pac = np->ipv6_ac_list;
1da177e4 LT	188	np->ipv6_ac_list = NULL;
1da177e4 LT	189
	190	prev_index = 0;
	191	while (pac) {
	192	struct ipv6_ac_socklist *next = pac->acl_next;
	193
	194	if (pac->acl_ifindex != prev_index) {
6c555490	195	dev = __dev_get_by_index(net, pac->acl_ifindex);
1da177e4 LT	196	prev_index = pac->acl_ifindex;
	197	}
	198	if (dev)
	199	ipv6_dev_ac_dec(dev, &pac->acl_addr);
	200	sock_kfree_s(sk, pac, sizeof(*pac));
	201	pac = next;
	202	}
a9ed4a29	203	rtnl_unlock();
1da177e4 LT	204	}
1da177e4 LT	205
83aa29ee WC	206	static void aca_get(struct ifacaddr6 *aca)
	207	{
	208	atomic_inc(&aca->aca_refcnt);
	209	}
	210
1da177e4 LT	211	static void aca_put(struct ifacaddr6 *ac)
	212	{
	213	if (atomic_dec_and_test(&ac->aca_refcnt)) {
	214	in6_dev_put(ac->aca_idev);
d8d1f30b	215	dst_release(&ac->aca_rt->dst);
1da177e4 LT	216	kfree(ac);
	217	}
	218	}
	219
83aa29ee WC	220	static struct ifacaddr6 aca_alloc(struct rt6_info rt,
	221	const struct in6_addr *addr)
	222	{
	223	struct inet6_dev *idev = rt->rt6i_idev;
	224	struct ifacaddr6 *aca;
	225
	226	aca = kzalloc(sizeof(*aca), GFP_ATOMIC);
	227	if (aca == NULL)
	228	return NULL;
	229
	230	aca->aca_addr = *addr;
	231	in6_dev_hold(idev);
	232	aca->aca_idev = idev;
	233	aca->aca_rt = rt;
	234	aca->aca_users = 1;
	235	/* aca_tstamp should be updated upon changes */
	236	aca->aca_cstamp = aca->aca_tstamp = jiffies;
	237	atomic_set(&aca->aca_refcnt, 1);
83aa29ee WC	238
	239	return aca;
	240	}
	241
1da177e4 LT	242	/*
	243	* device anycast group inc (add if not found)
	244	*/
013b4d90	245	int __ipv6_dev_ac_inc(struct inet6_dev idev, const struct in6_addr addr)
1da177e4 LT	246	{
1da177e4 LT	247	struct ifacaddr6 *aca;
1da177e4 LT	248	struct rt6_info *rt;
	249	int err;
	250
a9ed4a29 SD	251	ASSERT_RTNL();
a9ed4a29 SD	252
1da177e4 LT	253	write_lock_bh(&idev->lock);
	254	if (idev->dead) {
	255	err = -ENODEV;
	256	goto out;
	257	}
	258
	259	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
	260	if (ipv6_addr_equal(&aca->aca_addr, addr)) {
	261	aca->aca_users++;
	262	err = 0;
	263	goto out;
	264	}
	265	}
	266
8f031519	267	rt = addrconf_dst_alloc(idev, addr, true);
1da177e4	268	if (IS_ERR(rt)) {
1da177e4 LT	269	err = PTR_ERR(rt);
	270	goto out;
	271	}
83aa29ee WC	272	aca = aca_alloc(rt, addr);
	273	if (aca == NULL) {
	274	ip6_rt_put(rt);
	275	err = -ENOMEM;
	276	goto out;
	277	}
1da177e4 LT	278
	279	aca->aca_next = idev->ac_list;
	280	idev->ac_list = aca;
83aa29ee WC	281
	282	/* Hold this for addrconf_join_solict() below before we unlock,
	283	* it is already exposed via idev->ac_list.
	284	*/
	285	aca_get(aca);
1da177e4 LT	286	write_unlock_bh(&idev->lock);
1da177e4 LT	287
84f59370	288	ip6_ins_rt(rt);
1da177e4	289
013b4d90	290	addrconf_join_solict(idev->dev, &aca->aca_addr);
1da177e4 LT	291
	292	aca_put(aca);
	293	return 0;
	294	out:
	295	write_unlock_bh(&idev->lock);
1da177e4 LT	296	return err;
	297	}
	298
	299	/*
	300	* device anycast group decrement
	301	*/
b71d1d42	302	int __ipv6_dev_ac_dec(struct inet6_dev idev, const struct in6_addr addr)
1da177e4 LT	303	{
	304	struct ifacaddr6 aca, prev_aca;
	305
a9ed4a29 SD	306	ASSERT_RTNL();
a9ed4a29 SD	307
1da177e4 LT	308	write_lock_bh(&idev->lock);
	309	prev_aca = NULL;
	310	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
	311	if (ipv6_addr_equal(&aca->aca_addr, addr))
	312	break;
	313	prev_aca = aca;
	314	}
	315	if (!aca) {
	316	write_unlock_bh(&idev->lock);
	317	return -ENOENT;
	318	}
	319	if (--aca->aca_users > 0) {
	320	write_unlock_bh(&idev->lock);
	321	return 0;
	322	}
	323	if (prev_aca)
	324	prev_aca->aca_next = aca->aca_next;
	325	else
	326	idev->ac_list = aca->aca_next;
	327	write_unlock_bh(&idev->lock);
	328	addrconf_leave_solict(idev, &aca->aca_addr);
	329
d8d1f30b	330	dst_hold(&aca->aca_rt->dst);
84f59370	331	ip6_del_rt(aca->aca_rt);
1da177e4 LT	332
	333	aca_put(aca);
	334	return 0;
	335	}
	336
6c555490	337	/* called with rtnl_lock() */
b71d1d42	338	static int ipv6_dev_ac_dec(struct net_device dev, const struct in6_addr addr)
1da177e4	339	{
bb69ae04 ED	340	struct inet6_dev *idev = __in6_dev_get(dev);
bb69ae04 ED	341
1da177e4 LT	342	if (idev == NULL)
1da177e4 LT	343	return -ENODEV;
bb69ae04	344	return __ipv6_dev_ac_dec(idev, addr);
1da177e4	345	}
1ab1457c	346
381f4dca SD	347	void ipv6_ac_destroy_dev(struct inet6_dev *idev)
	348	{
	349	struct ifacaddr6 *aca;
	350
	351	write_lock_bh(&idev->lock);
	352	while ((aca = idev->ac_list) != NULL) {
	353	idev->ac_list = aca->aca_next;
	354	write_unlock_bh(&idev->lock);
	355
	356	addrconf_leave_solict(idev, &aca->aca_addr);
	357
	358	dst_hold(&aca->aca_rt->dst);
	359	ip6_del_rt(aca->aca_rt);
	360
	361	aca_put(aca);
	362
	363	write_lock_bh(&idev->lock);
	364	}
	365	write_unlock_bh(&idev->lock);
	366	}
	367
1da177e4 LT	368	/*
1da177e4 LT	369	* check if the interface has this anycast address
bb69ae04	370	* called with rcu_read_lock()
1da177e4	371	*/
a50feda5	372	static bool ipv6_chk_acast_dev(struct net_device dev, const struct in6_addr addr)
1da177e4 LT	373	{
	374	struct inet6_dev *idev;
	375	struct ifacaddr6 *aca;
	376
bb69ae04	377	idev = __in6_dev_get(dev);
1da177e4 LT	378	if (idev) {
	379	read_lock_bh(&idev->lock);
	380	for (aca = idev->ac_list; aca; aca = aca->aca_next)
	381	if (ipv6_addr_equal(&aca->aca_addr, addr))
	382	break;
	383	read_unlock_bh(&idev->lock);
cfcabdcc	384	return aca != NULL;
1da177e4	385	}
a50feda5	386	return false;
1da177e4 LT	387	}
	388
	389	/*
	390	* check if given interface (or any, if dev==0) has this anycast address
	391	*/
a50feda5 ED	392	bool ipv6_chk_acast_addr(struct net net, struct net_device dev,
a50feda5 ED	393	const struct in6_addr *addr)
1da177e4	394	{
a50feda5	395	bool found = false;
7562f876	396
c6d14c84	397	rcu_read_lock();
bb69ae04 ED	398	if (dev)
	399	found = ipv6_chk_acast_dev(dev, addr);
	400	else
	401	for_each_netdev_rcu(net, dev)
	402	if (ipv6_chk_acast_dev(dev, addr)) {
a50feda5	403	found = true;
bb69ae04 ED	404	break;
bb69ae04 ED	405	}
c6d14c84	406	rcu_read_unlock();
7562f876	407	return found;
1da177e4 LT	408	}
1da177e4 LT	409
7c90cc2d FLB	410	/* check if this anycast address is link-local on given interface or
	411	* is global
	412	*/
	413	bool ipv6_chk_acast_addr_src(struct net net, struct net_device dev,
	414	const struct in6_addr *addr)
	415	{
	416	return ipv6_chk_acast_addr(net,
	417	(ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ?
	418	dev : NULL),
	419	addr);
	420	}
1da177e4 LT	421
	422	#ifdef CONFIG_PROC_FS
	423	struct ac6_iter_state {
6ab57e7e	424	struct seq_net_private p;
1da177e4 LT	425	struct net_device *dev;
	426	struct inet6_dev *idev;
	427	};
	428
	429	#define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private)
	430
	431	static inline struct ifacaddr6 ac6_get_first(struct seq_file seq)
	432	{
	433	struct ifacaddr6 *im = NULL;
	434	struct ac6_iter_state *state = ac6_seq_private(seq);
6ab57e7e	435	struct net *net = seq_file_net(seq);
1da177e4	436
7562f876	437	state->idev = NULL;
ce81b76a	438	for_each_netdev_rcu(net, state->dev) {
1da177e4	439	struct inet6_dev *idev;
ce81b76a	440	idev = __in6_dev_get(state->dev);
1da177e4 LT	441	if (!idev)
	442	continue;
	443	read_lock_bh(&idev->lock);
	444	im = idev->ac_list;
	445	if (im) {
	446	state->idev = idev;
	447	break;
	448	}
	449	read_unlock_bh(&idev->lock);
	450	}
	451	return im;
	452	}
	453
	454	static struct ifacaddr6 ac6_get_next(struct seq_file seq, struct ifacaddr6 *im)
	455	{
	456	struct ac6_iter_state *state = ac6_seq_private(seq);
	457
	458	im = im->aca_next;
	459	while (!im) {
ce81b76a	460	if (likely(state->idev != NULL))
1da177e4	461	read_unlock_bh(&state->idev->lock);
ce81b76a ED	462
ce81b76a ED	463	state->dev = next_net_device_rcu(state->dev);
1da177e4 LT	464	if (!state->dev) {
	465	state->idev = NULL;
	466	break;
	467	}
ce81b76a	468	state->idev = __in6_dev_get(state->dev);
1da177e4 LT	469	if (!state->idev)
	470	continue;
	471	read_lock_bh(&state->idev->lock);
	472	im = state->idev->ac_list;
	473	}
	474	return im;
	475	}
	476
	477	static struct ifacaddr6 ac6_get_idx(struct seq_file seq, loff_t pos)
	478	{
	479	struct ifacaddr6 *im = ac6_get_first(seq);
	480	if (im)
	481	while (pos && (im = ac6_get_next(seq, im)) != NULL)
	482	--pos;
	483	return pos ? NULL : im;
	484	}
	485
	486	static void ac6_seq_start(struct seq_file seq, loff_t *pos)
ce81b76a	487	__acquires(RCU)
1da177e4	488	{
ce81b76a	489	rcu_read_lock();
1da177e4 LT	490	return ac6_get_idx(seq, *pos);
	491	}
	492
	493	static void ac6_seq_next(struct seq_file seq, void v, loff_t pos)
	494	{
ce81b76a ED	495	struct ifacaddr6 *im = ac6_get_next(seq, v);
ce81b76a ED	496
1da177e4 LT	497	++*pos;
	498	return im;
	499	}
	500
	501	static void ac6_seq_stop(struct seq_file seq, void v)
ce81b76a	502	__releases(RCU)
1da177e4 LT	503	{
1da177e4 LT	504	struct ac6_iter_state *state = ac6_seq_private(seq);
ce81b76a	505
1da177e4 LT	506	if (likely(state->idev != NULL)) {
1da177e4 LT	507	read_unlock_bh(&state->idev->lock);
ce81b76a	508	state->idev = NULL;
1da177e4	509	}
ce81b76a	510	rcu_read_unlock();
1da177e4 LT	511	}
	512
	513	static int ac6_seq_show(struct seq_file seq, void v)
	514	{
	515	struct ifacaddr6 im = (struct ifacaddr6 )v;
	516	struct ac6_iter_state *state = ac6_seq_private(seq);
	517
4b7a4274	518	seq_printf(seq, "%-4d %-15s %pi6 %5d\n",
1da177e4	519	state->dev->ifindex, state->dev->name,
b071195d	520	&im->aca_addr, im->aca_users);
1da177e4 LT	521	return 0;
	522	}
	523
56b3d975	524	static const struct seq_operations ac6_seq_ops = {
1da177e4 LT	525	.start = ac6_seq_start,
	526	.next = ac6_seq_next,
	527	.stop = ac6_seq_stop,
	528	.show = ac6_seq_show,
	529	};
	530
	531	static int ac6_seq_open(struct inode inode, struct file file)
	532	{
6ab57e7e DL	533	return seq_open_net(inode, file, &ac6_seq_ops,
6ab57e7e DL	534	sizeof(struct ac6_iter_state));
1da177e4 LT	535	}
1da177e4 LT	536
9a32144e	537	static const struct file_operations ac6_seq_fops = {
1da177e4 LT	538	.owner = THIS_MODULE,
	539	.open = ac6_seq_open,
	540	.read = seq_read,
	541	.llseek = seq_lseek,
6ab57e7e	542	.release = seq_release_net,
1da177e4 LT	543	};
1da177e4 LT	544
2c8c1e72	545	int __net_init ac6_proc_init(struct net *net)
1da177e4	546	{
d4beaa66	547	if (!proc_create("anycast6", S_IRUGO, net->proc_net, &ac6_seq_fops))
1da177e4 LT	548	return -ENOMEM;
	549
	550	return 0;
	551	}
	552
6ab57e7e	553	void ac6_proc_exit(struct net *net)
1da177e4	554	{
ece31ffd	555	remove_proc_entry("anycast6", net->proc_net);
1da177e4 LT	556	}
	557	#endif
	558