[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(dev, 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_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);
	}
}

/*
 *	device anycast group inc (add if not found)
 */
int ipv6_dev_ac_inc(struct net_device *dev, const struct in6_addr *addr)
{
	struct ifacaddr6 *aca;
	struct inet6_dev *idev;
	struct rt6_info *rt;
	int err;

	ASSERT_RTNL();

	idev = in6_dev_get(dev);

	if (idev == NULL)
		return -EINVAL;

	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;
		}
	}

	/*
	 *	not found: create a new one.
	 */

	aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC);

	if (aca == NULL) {
		err = -ENOMEM;
		goto out;
	}

	rt = addrconf_dst_alloc(idev, addr, true);
	if (IS_ERR(rt)) {
		kfree(aca);
		err = PTR_ERR(rt);
		goto out;
	}

	aca->aca_addr = *addr;
	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, 2);
	spin_lock_init(&aca->aca_lock);

	aca->aca_next = idev->ac_list;
	idev->ac_list = aca;
	write_unlock_bh(&idev->lock);

	ip6_ins_rt(rt);

	addrconf_join_solict(dev, &aca->aca_addr);

	aca_put(aca);
	return 0;
out:
	write_unlock_bh(&idev->lock);
	in6_dev_put(idev);
	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);
}

/*
 *	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	}
	124
	125	err = ipv6_dev_ac_inc(dev, 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
1da177e4 LT	206	static void aca_put(struct ifacaddr6 *ac)
	207	{
	208	if (atomic_dec_and_test(&ac->aca_refcnt)) {
	209	in6_dev_put(ac->aca_idev);
d8d1f30b	210	dst_release(&ac->aca_rt->dst);
1da177e4 LT	211	kfree(ac);
	212	}
	213	}
	214
	215	/*
	216	* device anycast group inc (add if not found)
	217	*/
b71d1d42	218	int ipv6_dev_ac_inc(struct net_device dev, const struct in6_addr addr)
1da177e4 LT	219	{
	220	struct ifacaddr6 *aca;
	221	struct inet6_dev *idev;
	222	struct rt6_info *rt;
	223	int err;
	224
a9ed4a29 SD	225	ASSERT_RTNL();
a9ed4a29 SD	226
1da177e4 LT	227	idev = in6_dev_get(dev);
	228
	229	if (idev == NULL)
	230	return -EINVAL;
	231
	232	write_lock_bh(&idev->lock);
	233	if (idev->dead) {
	234	err = -ENODEV;
	235	goto out;
	236	}
	237
	238	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
	239	if (ipv6_addr_equal(&aca->aca_addr, addr)) {
	240	aca->aca_users++;
	241	err = 0;
	242	goto out;
	243	}
	244	}
	245
	246	/*
	247	* not found: create a new one.
	248	*/
	249
0c600eda	250	aca = kzalloc(sizeof(struct ifacaddr6), GFP_ATOMIC);
1da177e4 LT	251
	252	if (aca == NULL) {
	253	err = -ENOMEM;
	254	goto out;
	255	}
	256
8f031519	257	rt = addrconf_dst_alloc(idev, addr, true);
1da177e4 LT	258	if (IS_ERR(rt)) {
	259	kfree(aca);
	260	err = PTR_ERR(rt);
	261	goto out;
	262	}
	263
4e3fd7a0	264	aca->aca_addr = *addr;
1da177e4 LT	265	aca->aca_idev = idev;
	266	aca->aca_rt = rt;
	267	aca->aca_users = 1;
	268	/* aca_tstamp should be updated upon changes */
	269	aca->aca_cstamp = aca->aca_tstamp = jiffies;
	270	atomic_set(&aca->aca_refcnt, 2);
	271	spin_lock_init(&aca->aca_lock);
	272
	273	aca->aca_next = idev->ac_list;
	274	idev->ac_list = aca;
	275	write_unlock_bh(&idev->lock);
	276
84f59370	277	ip6_ins_rt(rt);
1da177e4 LT	278
	279	addrconf_join_solict(dev, &aca->aca_addr);
	280
	281	aca_put(aca);
	282	return 0;
	283	out:
	284	write_unlock_bh(&idev->lock);
	285	in6_dev_put(idev);
	286	return err;
	287	}
	288
	289	/*
	290	* device anycast group decrement
	291	*/
b71d1d42	292	int __ipv6_dev_ac_dec(struct inet6_dev idev, const struct in6_addr addr)
1da177e4 LT	293	{
	294	struct ifacaddr6 aca, prev_aca;
	295
a9ed4a29 SD	296	ASSERT_RTNL();
a9ed4a29 SD	297
1da177e4 LT	298	write_lock_bh(&idev->lock);
	299	prev_aca = NULL;
	300	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
	301	if (ipv6_addr_equal(&aca->aca_addr, addr))
	302	break;
	303	prev_aca = aca;
	304	}
	305	if (!aca) {
	306	write_unlock_bh(&idev->lock);
	307	return -ENOENT;
	308	}
	309	if (--aca->aca_users > 0) {
	310	write_unlock_bh(&idev->lock);
	311	return 0;
	312	}
	313	if (prev_aca)
	314	prev_aca->aca_next = aca->aca_next;
	315	else
	316	idev->ac_list = aca->aca_next;
	317	write_unlock_bh(&idev->lock);
	318	addrconf_leave_solict(idev, &aca->aca_addr);
	319
d8d1f30b	320	dst_hold(&aca->aca_rt->dst);
84f59370	321	ip6_del_rt(aca->aca_rt);
1da177e4 LT	322
	323	aca_put(aca);
	324	return 0;
	325	}
	326
6c555490	327	/* called with rtnl_lock() */
b71d1d42	328	static int ipv6_dev_ac_dec(struct net_device dev, const struct in6_addr addr)
1da177e4	329	{
bb69ae04 ED	330	struct inet6_dev *idev = __in6_dev_get(dev);
bb69ae04 ED	331
1da177e4 LT	332	if (idev == NULL)
1da177e4 LT	333	return -ENODEV;
bb69ae04	334	return __ipv6_dev_ac_dec(idev, addr);
1da177e4	335	}
1ab1457c	336
1da177e4 LT	337	/*
1da177e4 LT	338	* check if the interface has this anycast address
bb69ae04	339	* called with rcu_read_lock()
1da177e4	340	*/
a50feda5	341	static bool ipv6_chk_acast_dev(struct net_device dev, const struct in6_addr addr)
1da177e4 LT	342	{
	343	struct inet6_dev *idev;
	344	struct ifacaddr6 *aca;
	345
bb69ae04	346	idev = __in6_dev_get(dev);
1da177e4 LT	347	if (idev) {
	348	read_lock_bh(&idev->lock);
	349	for (aca = idev->ac_list; aca; aca = aca->aca_next)
	350	if (ipv6_addr_equal(&aca->aca_addr, addr))
	351	break;
	352	read_unlock_bh(&idev->lock);
cfcabdcc	353	return aca != NULL;
1da177e4	354	}
a50feda5	355	return false;
1da177e4 LT	356	}
	357
	358	/*
	359	* check if given interface (or any, if dev==0) has this anycast address
	360	*/
a50feda5 ED	361	bool ipv6_chk_acast_addr(struct net net, struct net_device dev,
a50feda5 ED	362	const struct in6_addr *addr)
1da177e4	363	{
a50feda5	364	bool found = false;
7562f876	365
c6d14c84	366	rcu_read_lock();
bb69ae04 ED	367	if (dev)
	368	found = ipv6_chk_acast_dev(dev, addr);
	369	else
	370	for_each_netdev_rcu(net, dev)
	371	if (ipv6_chk_acast_dev(dev, addr)) {
a50feda5	372	found = true;
bb69ae04 ED	373	break;
bb69ae04 ED	374	}
c6d14c84	375	rcu_read_unlock();
7562f876	376	return found;
1da177e4 LT	377	}
1da177e4 LT	378
7c90cc2d FLB	379	/* check if this anycast address is link-local on given interface or
	380	* is global
	381	*/
	382	bool ipv6_chk_acast_addr_src(struct net net, struct net_device dev,
	383	const struct in6_addr *addr)
	384	{
	385	return ipv6_chk_acast_addr(net,
	386	(ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ?
	387	dev : NULL),
	388	addr);
	389	}
1da177e4 LT	390
	391	#ifdef CONFIG_PROC_FS
	392	struct ac6_iter_state {
6ab57e7e	393	struct seq_net_private p;
1da177e4 LT	394	struct net_device *dev;
	395	struct inet6_dev *idev;
	396	};
	397
	398	#define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private)
	399
	400	static inline struct ifacaddr6 ac6_get_first(struct seq_file seq)
	401	{
	402	struct ifacaddr6 *im = NULL;
	403	struct ac6_iter_state *state = ac6_seq_private(seq);
6ab57e7e	404	struct net *net = seq_file_net(seq);
1da177e4	405
7562f876	406	state->idev = NULL;
ce81b76a	407	for_each_netdev_rcu(net, state->dev) {
1da177e4	408	struct inet6_dev *idev;
ce81b76a	409	idev = __in6_dev_get(state->dev);
1da177e4 LT	410	if (!idev)
	411	continue;
	412	read_lock_bh(&idev->lock);
	413	im = idev->ac_list;
	414	if (im) {
	415	state->idev = idev;
	416	break;
	417	}
	418	read_unlock_bh(&idev->lock);
	419	}
	420	return im;
	421	}
	422
	423	static struct ifacaddr6 ac6_get_next(struct seq_file seq, struct ifacaddr6 *im)
	424	{
	425	struct ac6_iter_state *state = ac6_seq_private(seq);
	426
	427	im = im->aca_next;
	428	while (!im) {
ce81b76a	429	if (likely(state->idev != NULL))
1da177e4	430	read_unlock_bh(&state->idev->lock);
ce81b76a ED	431
ce81b76a ED	432	state->dev = next_net_device_rcu(state->dev);
1da177e4 LT	433	if (!state->dev) {
	434	state->idev = NULL;
	435	break;
	436	}
ce81b76a	437	state->idev = __in6_dev_get(state->dev);
1da177e4 LT	438	if (!state->idev)
	439	continue;
	440	read_lock_bh(&state->idev->lock);
	441	im = state->idev->ac_list;
	442	}
	443	return im;
	444	}
	445
	446	static struct ifacaddr6 ac6_get_idx(struct seq_file seq, loff_t pos)
	447	{
	448	struct ifacaddr6 *im = ac6_get_first(seq);
	449	if (im)
	450	while (pos && (im = ac6_get_next(seq, im)) != NULL)
	451	--pos;
	452	return pos ? NULL : im;
	453	}
	454
	455	static void ac6_seq_start(struct seq_file seq, loff_t *pos)
ce81b76a	456	__acquires(RCU)
1da177e4	457	{
ce81b76a	458	rcu_read_lock();
1da177e4 LT	459	return ac6_get_idx(seq, *pos);
	460	}
	461
	462	static void ac6_seq_next(struct seq_file seq, void v, loff_t pos)
	463	{
ce81b76a ED	464	struct ifacaddr6 *im = ac6_get_next(seq, v);
ce81b76a ED	465
1da177e4 LT	466	++*pos;
	467	return im;
	468	}
	469
	470	static void ac6_seq_stop(struct seq_file seq, void v)
ce81b76a	471	__releases(RCU)
1da177e4 LT	472	{
1da177e4 LT	473	struct ac6_iter_state *state = ac6_seq_private(seq);
ce81b76a	474
1da177e4 LT	475	if (likely(state->idev != NULL)) {
1da177e4 LT	476	read_unlock_bh(&state->idev->lock);
ce81b76a	477	state->idev = NULL;
1da177e4	478	}
ce81b76a	479	rcu_read_unlock();
1da177e4 LT	480	}
	481
	482	static int ac6_seq_show(struct seq_file seq, void v)
	483	{
	484	struct ifacaddr6 im = (struct ifacaddr6 )v;
	485	struct ac6_iter_state *state = ac6_seq_private(seq);
	486
4b7a4274	487	seq_printf(seq, "%-4d %-15s %pi6 %5d\n",
1da177e4	488	state->dev->ifindex, state->dev->name,
b071195d	489	&im->aca_addr, im->aca_users);
1da177e4 LT	490	return 0;
	491	}
	492
56b3d975	493	static const struct seq_operations ac6_seq_ops = {
1da177e4 LT	494	.start = ac6_seq_start,
	495	.next = ac6_seq_next,
	496	.stop = ac6_seq_stop,
	497	.show = ac6_seq_show,
	498	};
	499
	500	static int ac6_seq_open(struct inode inode, struct file file)
	501	{
6ab57e7e DL	502	return seq_open_net(inode, file, &ac6_seq_ops,
6ab57e7e DL	503	sizeof(struct ac6_iter_state));
1da177e4 LT	504	}
1da177e4 LT	505
9a32144e	506	static const struct file_operations ac6_seq_fops = {
1da177e4 LT	507	.owner = THIS_MODULE,
	508	.open = ac6_seq_open,
	509	.read = seq_read,
	510	.llseek = seq_lseek,
6ab57e7e	511	.release = seq_release_net,
1da177e4 LT	512	};
1da177e4 LT	513
2c8c1e72	514	int __net_init ac6_proc_init(struct net *net)
1da177e4	515	{
d4beaa66	516	if (!proc_create("anycast6", S_IRUGO, net->proc_net, &ac6_seq_fops))
1da177e4 LT	517	return -ENOMEM;
	518
	519	return 0;
	520	}
	521
6ab57e7e	522	void ac6_proc_exit(struct net *net)
1da177e4	523	{
ece31ffd	524	remove_proc_entry("anycast6", net->proc_net);
1da177e4 LT	525	}
	526	#endif
	527