mcast.c

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/*
 *	Multicast support for IPv6
 *	Linux INET6 implementation 
 *
 *	Authors:
 *	Pedro Roque		<[e-mail]>	
 *
 *	$Id: mcast.c,v 1.38 2001/08/15 07:36:31 davem Exp $
 *
 *	Based on linux/ipv4/igmp.c and linux/ipv4/ip_sockglue.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.
 */

/* Changes:
 *
 *	yoshfuji	: fix format of router-alert option
 */

#define __NO_VERSION__
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/sched.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 <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>

/* Set to 3 to get tracing... */
#define MCAST_DEBUG 2

#if MCAST_DEBUG >= 3
#define MDBG(x) printk x
#else
#define MDBG(x)
#endif

/* Big mc list lock for all the sockets */
static rwlock_t ipv6_sk_mc_lock = RW_LOCK_UNLOCKED;

static struct socket *igmp6_socket;

static void igmp6_join_group(struct ifmcaddr6 *ma);
static void igmp6_leave_group(struct ifmcaddr6 *ma);
void igmp6_timer_handler(unsigned long data);

#define IGMP6_UNSOLICITED_IVAL	(10*HZ)

/*
 *	socket join on multicast group
 */

int ipv6_sock_mc_join(struct sock *sk, int ifindex, struct in6_addr *addr)
{
	struct net_device *dev = NULL;
	struct ipv6_mc_socklist *mc_lst;
	struct ipv6_pinfo *np = &sk->net_pinfo.af_inet6;
	int err;

	if (!(ipv6_addr_type(addr) & IPV6_ADDR_MULTICAST))
		return -EINVAL;

	mc_lst = sock_kmalloc(sk, sizeof(struct ipv6_mc_socklist), GFP_KERNEL);

	if (mc_lst == NULL)
		return -ENOMEM;

	mc_lst->next = NULL;
	memcpy(&mc_lst->addr, addr, sizeof(struct in6_addr));

	if (ifindex == 0) {
		struct rt6_info *rt;
		rt = rt6_lookup(addr, NULL, 0, 0);
		if (rt) {
			dev = rt->rt6i_dev;
			dev_hold(dev);
			dst_release(&rt->u.dst);
		}
	} else
		dev = dev_get_by_index(ifindex);

	if (dev == NULL) {
		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
		return -ENODEV;
	}

	mc_lst->ifindex = dev->ifindex;

	/*
	 *	now add/increase the group membership on the device
	 */

	err = ipv6_dev_mc_inc(dev, addr);

	if (err) {
		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
		dev_put(dev);
		return err;
	}

	write_lock_bh(&ipv6_sk_mc_lock);
	mc_lst->next = np->ipv6_mc_list;
	np->ipv6_mc_list = mc_lst;
	write_unlock_bh(&ipv6_sk_mc_lock);

	dev_put(dev);

	return 0;
}

/*
 *	socket leave on multicast group
 */
int ipv6_sock_mc_drop(struct sock *sk, int ifindex, struct in6_addr *addr)
{
	struct ipv6_pinfo *np = &sk->net_pinfo.af_inet6;
	struct ipv6_mc_socklist *mc_lst, **lnk;

	write_lock_bh(&ipv6_sk_mc_lock);
	for (lnk = &np->ipv6_mc_list; (mc_lst = *lnk) !=NULL ; lnk = &mc_lst->next) {
		if (mc_lst->ifindex == ifindex &&
		    ipv6_addr_cmp(&mc_lst->addr, addr) == 0) {
			struct net_device *dev;

			*lnk = mc_lst->next;
			write_unlock_bh(&ipv6_sk_mc_lock);

			if ((dev = dev_get_by_index(ifindex)) != NULL) {
				ipv6_dev_mc_dec(dev, &mc_lst->addr);
				dev_put(dev);
			}
			sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
			return 0;
		}
	}
	write_unlock_bh(&ipv6_sk_mc_lock);

	return -ENOENT;
}

void ipv6_sock_mc_close(struct sock *sk)
{
	struct ipv6_pinfo *np = &sk->net_pinfo.af_inet6;
	struct ipv6_mc_socklist *mc_lst;

	write_lock_bh(&ipv6_sk_mc_lock);
	while ((mc_lst = np->ipv6_mc_list) != NULL) {
		struct net_device *dev;

		np->ipv6_mc_list = mc_lst->next;
		write_unlock_bh(&ipv6_sk_mc_lock);

		dev = dev_get_by_index(mc_lst->ifindex);
		if (dev) {
			ipv6_dev_mc_dec(dev, &mc_lst->addr);
			dev_put(dev);
		}

		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));

		write_lock_bh(&ipv6_sk_mc_lock);
	}
	write_unlock_bh(&ipv6_sk_mc_lock);
}

int inet6_mc_check(struct sock *sk, struct in6_addr *addr)
{
	struct ipv6_mc_socklist *mc;

	read_lock(&ipv6_sk_mc_lock);
	for (mc = sk->net_pinfo.af_inet6.ipv6_mc_list; mc; mc=mc->next) {
		if (ipv6_addr_cmp(&mc->addr, addr) == 0) {
			read_unlock(&ipv6_sk_mc_lock);
			return 1;
		}
	}
	read_unlock(&ipv6_sk_mc_lock);

	return 0;
}

static void ma_put(struct ifmcaddr6 *mc)
{
	if (atomic_dec_and_test(&mc->mca_refcnt)) {
		in6_dev_put(mc->idev);
		kfree(mc);
	}
}

static int igmp6_group_added(struct ifmcaddr6 *mc)
{
	struct net_device *dev = mc->idev->dev;
	char buf[MAX_ADDR_LEN];

	spin_lock_bh(&mc->mca_lock);
	if (!(mc->mca_flags&MAF_LOADED)) {
		mc->mca_flags |= MAF_LOADED;
		if (ndisc_mc_map(&mc->mca_addr, buf, dev, 0) == 0)
			dev_mc_add(dev, buf, dev->addr_len, 0);
	}
	spin_unlock_bh(&mc->mca_lock);

	if (dev->flags&IFF_UP)
		igmp6_join_group(mc);
	return 0;
}

static int igmp6_group_dropped(struct ifmcaddr6 *mc)
{
	struct net_device *dev = mc->idev->dev;
	char buf[MAX_ADDR_LEN];

	spin_lock_bh(&mc->mca_lock);
	if (mc->mca_flags&MAF_LOADED) {
		mc->mca_flags &= ~MAF_LOADED;
		if (ndisc_mc_map(&mc->mca_addr, buf, dev, 0) == 0)
			dev_mc_delete(dev, buf, dev->addr_len, 0);
	}
	spin_unlock_bh(&mc->mca_lock);

	if (dev->flags&IFF_UP)
		igmp6_leave_group(mc);
	return 0;
}


/*
 *	device multicast group inc (add if not found)
 */
int ipv6_dev_mc_inc(struct net_device *dev, struct in6_addr *addr)
{
	struct ifmcaddr6 *mc;
	struct inet6_dev *idev;

	idev = in6_dev_get(dev);

	if (idev == NULL)
		return -EINVAL;

	write_lock_bh(&idev->lock);
	if (idev->dead) {
		write_unlock_bh(&idev->lock);
		in6_dev_put(idev);
		return -ENODEV;
	}

	for (mc = idev->mc_list; mc; mc = mc->next) {
		if (ipv6_addr_cmp(&mc->mca_addr, addr) == 0) {
			mc->mca_users++;
			write_unlock_bh(&idev->lock);
			in6_dev_put(idev);
			return 0;
		}
	}

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

	mc = kmalloc(sizeof(struct ifmcaddr6), GFP_ATOMIC);

	if (mc == NULL) {
		write_unlock_bh(&idev->lock);
		in6_dev_put(idev);
		return -ENOMEM;
	}

	memset(mc, 0, sizeof(struct ifmcaddr6));
	mc->mca_timer.function = igmp6_timer_handler;
	mc->mca_timer.data = (unsigned long) mc;

	memcpy(&mc->mca_addr, addr, sizeof(struct in6_addr));
	mc->idev = idev;
	mc->mca_users = 1;
	atomic_set(&mc->mca_refcnt, 2);
	mc->mca_lock = SPIN_LOCK_UNLOCKED;

	mc->next = idev->mc_list;
	idev->mc_list = mc;
	write_unlock_bh(&idev->lock);

	igmp6_group_added(mc);
	ma_put(mc);
	return 0;
}

/*
 *	device multicast group del
 */
int ipv6_dev_mc_dec(struct net_device *dev, struct in6_addr *addr)
{
	struct inet6_dev *idev;
	struct ifmcaddr6 *ma, **map;

	idev = in6_dev_get(dev);
	if (idev == NULL)
		return -ENODEV;

	write_lock_bh(&idev->lock);
	for (map = &idev->mc_list; (ma=*map) != NULL; map = &ma->next) {
		if (ipv6_addr_cmp(&ma->mca_addr, addr) == 0) {
			if (--ma->mca_users == 0) {
				*map = ma->next;
				write_unlock_bh(&idev->lock);

				igmp6_group_dropped(ma);

				ma_put(ma);
				in6_dev_put(idev);
				return 0;
			}
			write_unlock_bh(&idev->lock);
			in6_dev_put(idev);
			return 0;
		}
	}
	write_unlock_bh(&idev->lock);
	in6_dev_put(idev);

	return -ENOENT;
}

/*
 *	check if the interface/address pair is valid
 */
int ipv6_chk_mcast_addr(struct net_device *dev, struct in6_addr *addr)
{
	struct inet6_dev *idev;
	struct ifmcaddr6 *mc;

	idev = in6_dev_get(dev);
	if (idev) {
		read_lock_bh(&idev->lock);
		for (mc = idev->mc_list; mc; mc=mc->next) {
			if (ipv6_addr_cmp(&mc->mca_addr, addr) == 0) {
				read_unlock_bh(&idev->lock);
				in6_dev_put(idev);
				return 1;
			}
		}
		read_unlock_bh(&idev->lock);
		in6_dev_put(idev);
	}
	return 0;
}

/*
 *	IGMP handling (alias multicast ICMPv6 messages)
 */

static void igmp6_group_queried(struct ifmcaddr6 *ma, unsigned long resptime)
{
	unsigned long delay = resptime;

	/* Do not start timer for addresses with link/host scope */
	if (ipv6_addr_type(&ma->mca_addr)&(IPV6_ADDR_LINKLOCAL|IPV6_ADDR_LOOPBACK))
		return;

	spin_lock(&ma->mca_lock);
	if (del_timer(&ma->mca_timer)) {
		atomic_dec(&ma->mca_refcnt);
		delay = ma->mca_timer.expires - jiffies;
	}

	if (delay >= resptime) {
		if (resptime)
			delay = net_random() % resptime;
		else
			delay = 1;
	}

	ma->mca_timer.expires = jiffies + delay;
	if (!mod_timer(&ma->mca_timer, jiffies + delay))
		atomic_inc(&ma->mca_refcnt);