[linux.git] / net / l2tp / l2tp_ip.c

/*
 * L2TPv3 IP encapsulation support
 *
 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
 *
 *	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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/icmp.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/random.h>
#include <linux/socket.h>
#include <linux/l2tp.h>
#include <linux/in.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/tcp_states.h>
#include <net/protocol.h>
#include <net/xfrm.h>

#include "l2tp_core.h"

struct l2tp_ip_sock {
	/* inet_sock has to be the first member of l2tp_ip_sock */
	struct inet_sock	inet;

	u32			conn_id;
	u32			peer_conn_id;
};

static DEFINE_RWLOCK(l2tp_ip_lock);
static struct hlist_head l2tp_ip_table;
static struct hlist_head l2tp_ip_bind_table;

static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
{
	return (struct l2tp_ip_sock *)sk;
}

static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
{
	struct sock *sk;

	sk_for_each_bound(sk, &l2tp_ip_bind_table) {
		struct inet_sock *inet = inet_sk(sk);
		struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);

		if (l2tp == NULL)
			continue;

		if ((l2tp->conn_id == tunnel_id) &&
		    net_eq(sock_net(sk), net) &&
		    !(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
		    !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
			goto found;
	}

	sk = NULL;
found:
	return sk;
}

static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
{
	struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
	if (sk)
		sock_hold(sk);

	return sk;
}

/* When processing receive frames, there are two cases to
 * consider. Data frames consist of a non-zero session-id and an
 * optional cookie. Control frames consist of a regular L2TP header
 * preceded by 32-bits of zeros.
 *
 * L2TPv3 Session Header Over IP
 *
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                           Session ID                          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |               Cookie (optional, maximum 64 bits)...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *                                                                 |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * L2TPv3 Control Message Header Over IP
 *
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                      (32 bits of zeros)                       |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |T|L|x|x|S|x|x|x|x|x|x|x|  Ver  |             Length            |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                     Control Connection ID                     |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |               Ns              |               Nr              |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * All control frames are passed to userspace.
 */
static int l2tp_ip_recv(struct sk_buff *skb)
{
	struct net *net = dev_net(skb->dev);
	struct sock *sk;
	u32 session_id;
	u32 tunnel_id;
	unsigned char *ptr, *optr;
	struct l2tp_session *session;
	struct l2tp_tunnel *tunnel = NULL;
	int length;

	/* Point to L2TP header */
	optr = ptr = skb->data;

	if (!pskb_may_pull(skb, 4))
		goto discard;

	session_id = ntohl(*((__be32 *) ptr));
	ptr += 4;

	/* RFC3931: L2TP/IP packets have the first 4 bytes containing
	 * the session_id. If it is 0, the packet is a L2TP control
	 * frame and the session_id value can be discarded.
	 */
	if (session_id == 0) {
		__skb_pull(skb, 4);
		goto pass_up;
	}

	/* Ok, this is a data packet. Lookup the session. */
	session = l2tp_session_find(net, NULL, session_id);
	if (session == NULL)
		goto discard;

	tunnel = session->tunnel;
	if (tunnel == NULL)
		goto discard;

	/* Trace packet contents, if enabled */
	if (tunnel->debug & L2TP_MSG_DATA) {
		length = min(32u, skb->len);
		if (!pskb_may_pull(skb, length))
			goto discard;

		pr_debug("%s: ip recv\n", tunnel->name);
		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
	}

	l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);

	return 0;

pass_up:
	/* Get the tunnel_id from the L2TP header */
	if (!pskb_may_pull(skb, 12))
		goto discard;

	if ((skb->data[0] & 0xc0) != 0xc0)
		goto discard;

	tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
	tunnel = l2tp_tunnel_find(net, tunnel_id);
	if (tunnel != NULL)
		sk = tunnel->sock;
	else {
		struct iphdr *iph = (struct iphdr *) skb_network_header(skb);

		read_lock_bh(&l2tp_ip_lock);
		sk = __l2tp_ip_bind_lookup(net, iph->daddr, 0, tunnel_id);
		read_unlock_bh(&l2tp_ip_lock);
	}

	if (sk == NULL)
		goto discard;

	sock_hold(sk);

	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_put;

	nf_reset(skb);

	return sk_receive_skb(sk, skb, 1);

discard_put:
	sock_put(sk);

discard:
	kfree_skb(skb);
	return 0;
}

static int l2tp_ip_open(struct sock *sk)
{
	/* Prevent autobind. We don't have ports. */
	inet_sk(sk)->inet_num = IPPROTO_L2TP;

	write_lock_bh(&l2tp_ip_lock);
	sk_add_node(sk, &l2tp_ip_table);
	write_unlock_bh(&l2tp_ip_lock);

	return 0;
}

static void l2tp_ip_close(struct sock *sk, long timeout)
{
	write_lock_bh(&l2tp_ip_lock);
	hlist_del_init(&sk->sk_bind_node);
	sk_del_node_init(sk);
	write_unlock_bh(&l2tp_ip_lock);
	sk_common_release(sk);
}

static void l2tp_ip_destroy_sock(struct sock *sk)
{
	struct sk_buff *skb;
	struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);

	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
		kfree_skb(skb);

	if (tunnel) {
		l2tp_tunnel_closeall(tunnel);
		sock_put(sk);
	}

	sk_refcnt_debug_dec(sk);
}

static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
	struct net *net = sock_net(sk);
	int ret;
	int chk_addr_ret;

	if (!sock_flag(sk, SOCK_ZAPPED))
		return -EINVAL;
	if (addr_len < sizeof(struct sockaddr_l2tpip))
		return -EINVAL;
	if (addr->l2tp_family != AF_INET)
		return -EINVAL;

	ret = -EADDRINUSE;
	read_lock_bh(&l2tp_ip_lock);
	if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr,
				  sk->sk_bound_dev_if, addr->l2tp_conn_id))
		goto out_in_use;

	read_unlock_bh(&l2tp_ip_lock);

	lock_sock(sk);
	if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
		goto out;

	chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
	ret = -EADDRNOTAVAIL;
	if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
	    chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
		goto out;

	if (addr->l2tp_addr.s_addr)
		inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
		inet->inet_saddr = 0;  /* Use device */
	sk_dst_reset(sk);

	l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;

	write_lock_bh(&l2tp_ip_lock);
	sk_add_bind_node(sk, &l2tp_ip_bind_table);
	sk_del_node_init(sk);
	write_unlock_bh(&l2tp_ip_lock);
	ret = 0;
	sock_reset_flag(sk, SOCK_ZAPPED);

out:
	release_sock(sk);

	return ret;

out_in_use:
	read_unlock_bh(&l2tp_ip_lock);

	return ret;
}

static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
	int rc;

	if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
		return -EINVAL;

	if (addr_len < sizeof(*lsa))
		return -EINVAL;

	if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
		return -EINVAL;

	rc = ip4_datagram_connect(sk, uaddr, addr_len);
	if (rc < 0)
		return rc;

	lock_sock(sk);

	l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;

	write_lock_bh(&l2tp_ip_lock);
	hlist_del_init(&sk->sk_bind_node);
	sk_add_bind_node(sk, &l2tp_ip_bind_table);
	write_unlock_bh(&l2tp_ip_lock);

	release_sock(sk);
	return rc;
}

static int l2tp_ip_disconnect(struct sock *sk, int flags)
{
	if (sock_flag(sk, SOCK_ZAPPED))
		return 0;

	return udp_disconnect(sk, flags);
}

static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
			   int *uaddr_len, int peer)
{
	struct sock *sk		= sock->sk;
	struct inet_sock *inet	= inet_sk(sk);
	struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;

	memset(lsa, 0, sizeof(*lsa));
	lsa->l2tp_family = AF_INET;
	if (peer) {
		if (!inet->inet_dport)
			return -ENOTCONN;
		lsa->l2tp_conn_id = lsk->peer_conn_id;
		lsa->l2tp_addr.s_addr = inet->inet_daddr;
	} else {
		__be32 addr = inet->inet_rcv_saddr;
		if (!addr)
			addr = inet->inet_saddr;
		lsa->l2tp_conn_id = lsk->conn_id;
		lsa->l2tp_addr.s_addr = addr;
	}
	*uaddr_len = sizeof(*lsa);
	return 0;
}

static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
{
	int rc;

	/* Charge it to the socket, dropping if the queue is full. */
	rc = sock_queue_rcv_skb(sk, skb);
	if (rc < 0)
		goto drop;

	return 0;

drop:
	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
	kfree_skb(skb);
	return -1;
}

/* Userspace will call sendmsg() on the tunnel socket to send L2TP
 * control frames.
 */
static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
{
	struct sk_buff *skb;
	int rc;
	struct inet_sock *inet = inet_sk(sk);
	struct rtable *rt = NULL;
	struct flowi4 *fl4;
	int connected = 0;
	__be32 daddr;

	lock_sock(sk);

	rc = -ENOTCONN;
	if (sock_flag(sk, SOCK_DEAD))
		goto out;

	/* Get and verify the address. */
	if (msg->msg_name) {
		DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
		rc = -EINVAL;
		if (msg->msg_namelen < sizeof(*lip))
			goto out;

		if (lip->l2tp_family != AF_INET) {
			rc = -EAFNOSUPPORT;
			if (lip->l2tp_family != AF_UNSPEC)
				goto out;
		}

		daddr = lip->l2tp_addr.s_addr;
	} else {
		rc = -EDESTADDRREQ;
		if (sk->sk_state != TCP_ESTABLISHED)
			goto out;

		daddr = inet->inet_daddr;
		connected = 1;
	}

	/* Allocate a socket buffer */
	rc = -ENOMEM;
	skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
			   4 + len, 0, GFP_KERNEL);
	if (!skb)
		goto error;

	/* Reserve space for headers, putting IP header on 4-byte boundary. */
	skb_reserve(skb, 2 + NET_SKB_PAD);
	skb_reset_network_header(skb);
	skb_reserve(skb, sizeof(struct iphdr));
	skb_reset_transport_header(skb);

	/* Insert 0 session_id */
	*((__be32 *) skb_put(skb, 4)) = 0;

	/* Copy user data into skb */
	rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
	if (rc < 0) {
		kfree_skb(skb);
		goto error;
	}

	fl4 = &inet->cork.fl.u.ip4;
	if (connected)
		rt = (struct rtable *) __sk_dst_check(sk, 0);

	rcu_read_lock();
	if (rt == NULL) {
		const struct ip_options_rcu *inet_opt;

		inet_opt = rcu_dereference(inet->inet_opt);

		/* Use correct destination address if we have options. */
		if (inet_opt && inet_opt->opt.srr)
			daddr = inet_opt->opt.faddr;

		/* If this fails, retransmit mechanism of transport layer will
		 * keep trying until route appears or the connection times
		 * itself out.
		 */
		rt = ip_route_output_ports(sock_net(sk), fl4, sk,
					   daddr, inet->inet_saddr,
					   inet->inet_dport, inet->inet_sport,
					   sk->sk_protocol, RT_CONN_FLAGS(sk),
					   sk->sk_bound_dev_if);
		if (IS_ERR(rt))
			goto no_route;
		if (connected) {
			sk_setup_caps(sk, &rt->dst);
		} else {
			skb_dst_set(skb, &rt->dst);
			goto xmit;
		}
	}

	/* We dont need to clone dst here, it is guaranteed to not disappear.
	 *  __dev_xmit_skb() might force a refcount if needed.
	 */
	skb_dst_set_noref(skb, &rt->dst);

xmit:
	/* Queue the packet to IP for output */
	rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
	rcu_read_unlock();

error:
	if (rc >= 0)
		rc = len;

out:
	release_sock(sk);
	return rc;

no_route:
	rcu_read_unlock();
	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
	kfree_skb(skb);
	rc = -EHOSTUNREACH;
	goto out;
}

static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
			   size_t len, int noblock, int flags, int *addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	size_t copied = 0;
	int err = -EOPNOTSUPP;
	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
	struct sk_buff *skb;

	if (flags & MSG_OOB)
		goto out;

	skb = skb_recv_datagram(sk, flags, noblock, &err);
	if (!skb)
		goto out;

	copied = skb->len;
	if (len < copied) {
		msg->msg_flags |= MSG_TRUNC;
		copied = len;
	}

	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
	if (err)
		goto done;

	sock_recv_timestamp(msg, sk, skb);

	/* Copy the address. */
	if (sin) {
		sin->sin_family = AF_INET;
		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
		sin->sin_port = 0;
		memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
		*addr_len = sizeof(*sin);
	}
	if (inet->cmsg_flags)
		ip_cmsg_recv(msg, skb);
	if (flags & MSG_TRUNC)
		copied = skb->len;
done:
	skb_free_datagram(sk, skb);
out:
	return err ? err : copied;
}

static struct proto l2tp_ip_prot = {
	.name		   = "L2TP/IP",
	.owner		   = THIS_MODULE,
	.init		   = l2tp_ip_open,
	.close		   = l2tp_ip_close,
	.bind		   = l2tp_ip_bind,
	.connect	   = l2tp_ip_connect,
	.disconnect	   = l2tp_ip_disconnect,
	.ioctl		   = udp_ioctl,
	.destroy	   = l2tp_ip_destroy_sock,
	.setsockopt	   = ip_setsockopt,
	.getsockopt	   = ip_getsockopt,
	.sendmsg	   = l2tp_ip_sendmsg,
	.recvmsg	   = l2tp_ip_recvmsg,
	.backlog_rcv	   = l2tp_ip_backlog_recv,
	.hash		   = inet_hash,
	.unhash		   = inet_unhash,
	.obj_size	   = sizeof(struct l2tp_ip_sock),
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
#endif
};

static const struct proto_ops l2tp_ip_ops = {
	.family		   = PF_INET,
	.owner		   = THIS_MODULE,
	.release	   = inet_release,
	.bind		   = inet_bind,
	.connect	   = inet_dgram_connect,
	.socketpair	   = sock_no_socketpair,
	.accept		   = sock_no_accept,
	.getname	   = l2tp_ip_getname,
	.poll		   = datagram_poll,
	.ioctl		   = inet_ioctl,
	.listen		   = sock_no_listen,
	.shutdown	   = inet_shutdown,
	.setsockopt	   = sock_common_setsockopt,
	.getsockopt	   = sock_common_getsockopt,
	.sendmsg	   = inet_sendmsg,
	.recvmsg	   = sock_common_recvmsg,
	.mmap		   = sock_no_mmap,
	.sendpage	   = sock_no_sendpage,
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_sock_common_setsockopt,
	.compat_getsockopt = compat_sock_common_getsockopt,
#endif
};

static struct inet_protosw l2tp_ip_protosw = {
	.type		= SOCK_DGRAM,
	.protocol	= IPPROTO_L2TP,
	.prot		= &l2tp_ip_prot,
	.ops		= &l2tp_ip_ops,
};

static struct net_protocol l2tp_ip_protocol __read_mostly = {
	.handler	= l2tp_ip_recv,
	.netns_ok	= 1,
};

static int __init l2tp_ip_init(void)
{
	int err;

	pr_info("L2TP IP encapsulation support (L2TPv3)\n");

	err = proto_register(&l2tp_ip_prot, 1);
	if (err != 0)
		goto out;

	err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
	if (err)
		goto out1;

	inet_register_protosw(&l2tp_ip_protosw);
	return 0;

out1:
	proto_unregister(&l2tp_ip_prot);
out:
	return err;
}

static void __exit l2tp_ip_exit(void)
{
	inet_unregister_protosw(&l2tp_ip_protosw);
	inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
	proto_unregister(&l2tp_ip_prot);
}

module_init(l2tp_ip_init);
module_exit(l2tp_ip_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Chapman <[email protected]>");
MODULE_DESCRIPTION("L2TP over IP");
MODULE_VERSION("1.0");

/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
 * enums
 */
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);
Commit	Line	Data
0d76751f JC	1	/*
	2	* L2TPv3 IP encapsulation support
	3	*
	4	* Copyright (c) 2008,2009,2010 Katalix Systems Ltd
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
a4ca44fa JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
a4ca44fa JP	13
0d76751f JC	14	#include <linux/icmp.h>
	15	#include <linux/module.h>
	16	#include <linux/skbuff.h>
	17	#include <linux/random.h>
	18	#include <linux/socket.h>
	19	#include <linux/l2tp.h>
	20	#include <linux/in.h>
	21	#include <net/sock.h>
	22	#include <net/ip.h>
	23	#include <net/icmp.h>
	24	#include <net/udp.h>
	25	#include <net/inet_common.h>
	26	#include <net/inet_hashtables.h>
	27	#include <net/tcp_states.h>
	28	#include <net/protocol.h>
	29	#include <net/xfrm.h>
	30
	31	#include "l2tp_core.h"
	32
	33	struct l2tp_ip_sock {
	34	/* inet_sock has to be the first member of l2tp_ip_sock */
	35	struct inet_sock inet;
	36
c8657fd5 JC	37	u32 conn_id;
c8657fd5 JC	38	u32 peer_conn_id;
0d76751f JC	39	};
	40
	41	static DEFINE_RWLOCK(l2tp_ip_lock);
	42	static struct hlist_head l2tp_ip_table;
	43	static struct hlist_head l2tp_ip_bind_table;
	44
	45	static inline struct l2tp_ip_sock l2tp_ip_sk(const struct sock sk)
	46	{
	47	return (struct l2tp_ip_sock *)sk;
	48	}
	49
	50	static struct sock __l2tp_ip_bind_lookup(struct net net, __be32 laddr, int dif, u32 tunnel_id)
	51	{
0d76751f JC	52	struct sock *sk;
0d76751f JC	53
b67bfe0d	54	sk_for_each_bound(sk, &l2tp_ip_bind_table) {
0d76751f JC	55	struct inet_sock *inet = inet_sk(sk);
	56	struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
	57
	58	if (l2tp == NULL)
	59	continue;
	60
	61	if ((l2tp->conn_id == tunnel_id) &&
e83726b0	62	net_eq(sock_net(sk), net) &&
0d76751f JC	63	!(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
	64	!(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
	65	goto found;
	66	}
	67
	68	sk = NULL;
	69	found:
	70	return sk;
	71	}
	72
	73	static inline struct sock l2tp_ip_bind_lookup(struct net net, __be32 laddr, int dif, u32 tunnel_id)
	74	{
	75	struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
	76	if (sk)
	77	sock_hold(sk);
	78
	79	return sk;
	80	}
	81
	82	/* When processing receive frames, there are two cases to
	83	* consider. Data frames consist of a non-zero session-id and an
	84	* optional cookie. Control frames consist of a regular L2TP header
	85	* preceded by 32-bits of zeros.
	86	*
	87	* L2TPv3 Session Header Over IP
	88	*
	89	* 0 1 2 3
	90	* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	91	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	92	* \| Session ID \|
	93	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	94	* \| Cookie (optional, maximum 64 bits)...
	95	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	96	* \|
	97	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	98	*
	99	* L2TPv3 Control Message Header Over IP
	100	*
	101	* 0 1 2 3
	102	* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	103	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	104	* \| (32 bits of zeros) \|
	105	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	106	* \|T\|L\|x\|x\|S\|x\|x\|x\|x\|x\|x\|x\| Ver \| Length \|
	107	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	108	* \| Control Connection ID \|
	109	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	110	* \| Ns \| Nr \|
	111	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	112	*
	113	* All control frames are passed to userspace.
	114	*/
	115	static int l2tp_ip_recv(struct sk_buff *skb)
	116	{
9d6ddb19	117	struct net *net = dev_net(skb->dev);
0d76751f JC	118	struct sock *sk;
	119	u32 session_id;
	120	u32 tunnel_id;
	121	unsigned char ptr, optr;
	122	struct l2tp_session *session;
	123	struct l2tp_tunnel *tunnel = NULL;
	124	int length;
0d76751f JC	125
	126	/* Point to L2TP header */
	127	optr = ptr = skb->data;
	128
	129	if (!pskb_may_pull(skb, 4))
	130	goto discard;
	131
	132	session_id = ntohl(((__be32 ) ptr));
	133	ptr += 4;
	134
	135	/* RFC3931: L2TP/IP packets have the first 4 bytes containing
	136	* the session_id. If it is 0, the packet is a L2TP control
	137	* frame and the session_id value can be discarded.
	138	*/
	139	if (session_id == 0) {
	140	__skb_pull(skb, 4);
	141	goto pass_up;
	142	}
	143
	144	/* Ok, this is a data packet. Lookup the session. */
9d6ddb19	145	session = l2tp_session_find(net, NULL, session_id);
0d76751f JC	146	if (session == NULL)
	147	goto discard;
	148
	149	tunnel = session->tunnel;
	150	if (tunnel == NULL)
	151	goto discard;
	152
	153	/* Trace packet contents, if enabled */
	154	if (tunnel->debug & L2TP_MSG_DATA) {
	155	length = min(32u, skb->len);
	156	if (!pskb_may_pull(skb, length))
	157	goto discard;
	158
a4ca44fa JP	159	pr_debug("%s: ip recv\n", tunnel->name);
a4ca44fa JP	160	print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
0d76751f JC	161	}
	162
	163	l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
	164
	165	return 0;
	166
	167	pass_up:
	168	/* Get the tunnel_id from the L2TP header */
	169	if (!pskb_may_pull(skb, 12))
	170	goto discard;
	171
	172	if ((skb->data[0] & 0xc0) != 0xc0)
	173	goto discard;
	174
	175	tunnel_id = ntohl((__be32 ) &skb->data[4]);
9d6ddb19	176	tunnel = l2tp_tunnel_find(net, tunnel_id);
0d76751f JC	177	if (tunnel != NULL)
	178	sk = tunnel->sock;
	179	else {
	180	struct iphdr iph = (struct iphdr ) skb_network_header(skb);
	181
	182	read_lock_bh(&l2tp_ip_lock);
9d6ddb19	183	sk = __l2tp_ip_bind_lookup(net, iph->daddr, 0, tunnel_id);
0d76751f JC	184	read_unlock_bh(&l2tp_ip_lock);
	185	}
	186
	187	if (sk == NULL)
	188	goto discard;
	189
	190	sock_hold(sk);
	191
	192	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
	193	goto discard_put;
	194
	195	nf_reset(skb);
	196
	197	return sk_receive_skb(sk, skb, 1);
	198
	199	discard_put:
	200	sock_put(sk);
	201
	202	discard:
	203	kfree_skb(skb);
	204	return 0;
	205	}
	206
	207	static int l2tp_ip_open(struct sock *sk)
	208	{
	209	/* Prevent autobind. We don't have ports. */
	210	inet_sk(sk)->inet_num = IPPROTO_L2TP;
	211
	212	write_lock_bh(&l2tp_ip_lock);
	213	sk_add_node(sk, &l2tp_ip_table);
	214	write_unlock_bh(&l2tp_ip_lock);
	215
	216	return 0;
	217	}
	218
	219	static void l2tp_ip_close(struct sock *sk, long timeout)
	220	{
	221	write_lock_bh(&l2tp_ip_lock);
	222	hlist_del_init(&sk->sk_bind_node);
d1f224ae	223	sk_del_node_init(sk);
0d76751f JC	224	write_unlock_bh(&l2tp_ip_lock);
	225	sk_common_release(sk);
	226	}
	227
	228	static void l2tp_ip_destroy_sock(struct sock *sk)
	229	{
	230	struct sk_buff *skb;
93606317	231	struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
0d76751f JC	232
	233	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
	234	kfree_skb(skb);
	235
93606317 TP	236	if (tunnel) {
	237	l2tp_tunnel_closeall(tunnel);
	238	sock_put(sk);
	239	}
	240
0d76751f JC	241	sk_refcnt_debug_dec(sk);
	242	}
	243
	244	static int l2tp_ip_bind(struct sock sk, struct sockaddr uaddr, int addr_len)
	245	{
	246	struct inet_sock *inet = inet_sk(sk);
	247	struct sockaddr_l2tpip addr = (struct sockaddr_l2tpip ) uaddr;
9d6ddb19	248	struct net *net = sock_net(sk);
c51ce497	249	int ret;
0d76751f JC	250	int chk_addr_ret;
0d76751f JC	251
c51ce497 JC	252	if (!sock_flag(sk, SOCK_ZAPPED))
	253	return -EINVAL;
	254	if (addr_len < sizeof(struct sockaddr_l2tpip))
	255	return -EINVAL;
	256	if (addr->l2tp_family != AF_INET)
	257	return -EINVAL;
	258
0d76751f JC	259	ret = -EADDRINUSE;
0d76751f JC	260	read_lock_bh(&l2tp_ip_lock);
9d6ddb19 DM	261	if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr,
9d6ddb19 DM	262	sk->sk_bound_dev_if, addr->l2tp_conn_id))
0d76751f JC	263	goto out_in_use;
	264
	265	read_unlock_bh(&l2tp_ip_lock);
	266
	267	lock_sock(sk);
	268	if (sk->sk_state != TCP_CLOSE \|\| addr_len < sizeof(struct sockaddr_l2tpip))
	269	goto out;
	270
9d6ddb19	271	chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
0d76751f JC	272	ret = -EADDRNOTAVAIL;
	273	if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
	274	chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
	275	goto out;
	276
c9be48dc JC	277	if (addr->l2tp_addr.s_addr)
c9be48dc JC	278	inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
0d76751f JC	279	if (chk_addr_ret == RTN_MULTICAST \|\| chk_addr_ret == RTN_BROADCAST)
	280	inet->inet_saddr = 0; /* Use device */
	281	sk_dst_reset(sk);
	282
	283	l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
	284
	285	write_lock_bh(&l2tp_ip_lock);
	286	sk_add_bind_node(sk, &l2tp_ip_bind_table);
	287	sk_del_node_init(sk);
	288	write_unlock_bh(&l2tp_ip_lock);
	289	ret = 0;
c51ce497 JC	290	sock_reset_flag(sk, SOCK_ZAPPED);
c51ce497 JC	291
0d76751f JC	292	out:
	293	release_sock(sk);
	294
	295	return ret;
	296
	297	out_in_use:
	298	read_unlock_bh(&l2tp_ip_lock);
	299
	300	return ret;
	301	}
	302
	303	static int l2tp_ip_connect(struct sock sk, struct sockaddr uaddr, int addr_len)
	304	{
0d76751f	305	struct sockaddr_l2tpip lsa = (struct sockaddr_l2tpip ) uaddr;
de3c7a18	306	int rc;
0d76751f	307
c51ce497 JC	308	if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
	309	return -EINVAL;
	310
0d76751f	311	if (addr_len < sizeof(*lsa))
de3c7a18	312	return -EINVAL;
2f16270f	313
0d76751f	314	if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
de3c7a18	315	return -EINVAL;
0d76751f	316
de3c7a18 JC	317	rc = ip4_datagram_connect(sk, uaddr, addr_len);
	318	if (rc < 0)
	319	return rc;
0d76751f	320
de3c7a18	321	lock_sock(sk);
0d76751f JC	322
	323	l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
	324
0d76751f JC	325	write_lock_bh(&l2tp_ip_lock);
	326	hlist_del_init(&sk->sk_bind_node);
	327	sk_add_bind_node(sk, &l2tp_ip_bind_table);
	328	write_unlock_bh(&l2tp_ip_lock);
	329
2f16270f	330	release_sock(sk);
0d76751f JC	331	return rc;
	332	}
	333
c51ce497 JC	334	static int l2tp_ip_disconnect(struct sock *sk, int flags)
	335	{
	336	if (sock_flag(sk, SOCK_ZAPPED))
	337	return 0;
	338
	339	return udp_disconnect(sk, flags);
	340	}
	341
0d76751f JC	342	static int l2tp_ip_getname(struct socket sock, struct sockaddr uaddr,
	343	int *uaddr_len, int peer)
	344	{
	345	struct sock *sk = sock->sk;
	346	struct inet_sock *inet = inet_sk(sk);
	347	struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
	348	struct sockaddr_l2tpip lsa = (struct sockaddr_l2tpip )uaddr;
	349
	350	memset(lsa, 0, sizeof(*lsa));
	351	lsa->l2tp_family = AF_INET;
	352	if (peer) {
	353	if (!inet->inet_dport)
	354	return -ENOTCONN;
	355	lsa->l2tp_conn_id = lsk->peer_conn_id;
	356	lsa->l2tp_addr.s_addr = inet->inet_daddr;
	357	} else {
	358	__be32 addr = inet->inet_rcv_saddr;
	359	if (!addr)
	360	addr = inet->inet_saddr;
	361	lsa->l2tp_conn_id = lsk->conn_id;
	362	lsa->l2tp_addr.s_addr = addr;
	363	}
	364	uaddr_len = sizeof(lsa);
	365	return 0;
	366	}
	367
	368	static int l2tp_ip_backlog_recv(struct sock sk, struct sk_buff skb)
	369	{
	370	int rc;
	371
0d76751f JC	372	/* Charge it to the socket, dropping if the queue is full. */
	373	rc = sock_queue_rcv_skb(sk, skb);
	374	if (rc < 0)
	375	goto drop;
	376
	377	return 0;
	378
	379	drop:
9d6ddb19	380	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
0d76751f JC	381	kfree_skb(skb);
	382	return -1;
	383	}
	384
	385	/* Userspace will call sendmsg() on the tunnel socket to send L2TP
	386	* control frames.
	387	*/
	388	static int l2tp_ip_sendmsg(struct kiocb iocb, struct sock sk, struct msghdr *msg, size_t len)
	389	{
	390	struct sk_buff *skb;
	391	int rc;
0d76751f	392	struct inet_sock *inet = inet_sk(sk);
0d76751f	393	struct rtable *rt = NULL;
fdbb0f07	394	struct flowi4 *fl4;
0d76751f JC	395	int connected = 0;
	396	__be32 daddr;
	397
2f16270f DM	398	lock_sock(sk);
	399
	400	rc = -ENOTCONN;
0d76751f	401	if (sock_flag(sk, SOCK_DEAD))
2f16270f	402	goto out;
0d76751f JC	403
	404	/* Get and verify the address. */
	405	if (msg->msg_name) {
342dfc30	406	DECLARE_SOCKADDR(struct sockaddr_l2tpip *, lip, msg->msg_name);
2f16270f	407	rc = -EINVAL;
0d76751f	408	if (msg->msg_namelen < sizeof(*lip))
2f16270f	409	goto out;
0d76751f JC	410
0d76751f JC	411	if (lip->l2tp_family != AF_INET) {
2f16270f	412	rc = -EAFNOSUPPORT;
0d76751f	413	if (lip->l2tp_family != AF_UNSPEC)
2f16270f	414	goto out;
0d76751f JC	415	}
	416
	417	daddr = lip->l2tp_addr.s_addr;
	418	} else {
84768edb	419	rc = -EDESTADDRREQ;
0d76751f	420	if (sk->sk_state != TCP_ESTABLISHED)
84768edb	421	goto out;
0d76751f JC	422
	423	daddr = inet->inet_daddr;
	424	connected = 1;
	425	}
	426
	427	/* Allocate a socket buffer */
	428	rc = -ENOMEM;
	429	skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
	430	4 + len, 0, GFP_KERNEL);
	431	if (!skb)
	432	goto error;
	433
	434	/* Reserve space for headers, putting IP header on 4-byte boundary. */
	435	skb_reserve(skb, 2 + NET_SKB_PAD);
	436	skb_reset_network_header(skb);
	437	skb_reserve(skb, sizeof(struct iphdr));
	438	skb_reset_transport_header(skb);
	439
	440	/* Insert 0 session_id */
	441	((__be32 ) skb_put(skb, 4)) = 0;
	442
	443	/* Copy user data into skb */
	444	rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
	445	if (rc < 0) {
	446	kfree_skb(skb);
	447	goto error;
	448	}
	449
fdbb0f07	450	fl4 = &inet->cork.fl.u.ip4;
0d76751f JC	451	if (connected)
	452	rt = (struct rtable *) __sk_dst_check(sk, 0);
	453
081b1b1b	454	rcu_read_lock();
0d76751f	455	if (rt == NULL) {
081b1b1b	456	const struct ip_options_rcu *inet_opt;
f6d8bd05	457
778865a5	458	inet_opt = rcu_dereference(inet->inet_opt);
f6d8bd05	459
0d76751f	460	/* Use correct destination address if we have options. */
f6d8bd05 ED	461	if (inet_opt && inet_opt->opt.srr)
f6d8bd05 ED	462	daddr = inet_opt->opt.faddr;
0d76751f	463
78fbfd8a DM	464	/* If this fails, retransmit mechanism of transport layer will
	465	* keep trying until route appears or the connection times
	466	* itself out.
	467	*/
fdbb0f07	468	rt = ip_route_output_ports(sock_net(sk), fl4, sk,
78fbfd8a DM	469	daddr, inet->inet_saddr,
	470	inet->inet_dport, inet->inet_sport,
	471	sk->sk_protocol, RT_CONN_FLAGS(sk),
	472	sk->sk_bound_dev_if);
	473	if (IS_ERR(rt))
	474	goto no_route;
4399a4df	475	if (connected) {
081b1b1b	476	sk_setup_caps(sk, &rt->dst);
4399a4df ED	477	} else {
	478	skb_dst_set(skb, &rt->dst);
	479	goto xmit;
	480	}
0d76751f	481	}
081b1b1b ED	482
	483	/* We dont need to clone dst here, it is guaranteed to not disappear.
	484	* __dev_xmit_skb() might force a refcount if needed.
	485	*/
	486	skb_dst_set_noref(skb, &rt->dst);
0d76751f	487
4399a4df	488	xmit:
0d76751f	489	/* Queue the packet to IP for output */
b0270e91	490	rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
081b1b1b	491	rcu_read_unlock();
0d76751f JC	492
0d76751f JC	493	error:
c8657fd5	494	if (rc >= 0)
0d76751f	495	rc = len;
0d76751f	496
2f16270f DM	497	out:
2f16270f DM	498	release_sock(sk);
0d76751f JC	499	return rc;
	500
	501	no_route:
081b1b1b	502	rcu_read_unlock();
0d76751f JC	503	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
0d76751f JC	504	kfree_skb(skb);
2f16270f DM	505	rc = -EHOSTUNREACH;
2f16270f DM	506	goto out;
0d76751f JC	507	}
	508
	509	static int l2tp_ip_recvmsg(struct kiocb iocb, struct sock sk, struct msghdr *msg,
	510	size_t len, int noblock, int flags, int *addr_len)
	511	{
	512	struct inet_sock *inet = inet_sk(sk);
0d76751f JC	513	size_t copied = 0;
0d76751f JC	514	int err = -EOPNOTSUPP;
342dfc30	515	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
0d76751f JC	516	struct sk_buff *skb;
	517
	518	if (flags & MSG_OOB)
	519	goto out;
	520
0d76751f JC	521	skb = skb_recv_datagram(sk, flags, noblock, &err);
	522	if (!skb)
	523	goto out;
	524
	525	copied = skb->len;
	526	if (len < copied) {
	527	msg->msg_flags \|= MSG_TRUNC;
	528	copied = len;
	529	}
	530
	531	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
	532	if (err)
	533	goto done;
	534
	535	sock_recv_timestamp(msg, sk, skb);
	536
	537	/* Copy the address. */
	538	if (sin) {
	539	sin->sin_family = AF_INET;
	540	sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
	541	sin->sin_port = 0;
	542	memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
bceaa902	543	addr_len = sizeof(sin);
0d76751f JC	544	}
	545	if (inet->cmsg_flags)
	546	ip_cmsg_recv(msg, skb);
	547	if (flags & MSG_TRUNC)
	548	copied = skb->len;
	549	done:
	550	skb_free_datagram(sk, skb);
	551	out:
c8657fd5	552	return err ? err : copied;
0d76751f JC	553	}
0d76751f JC	554
fc130840	555	static struct proto l2tp_ip_prot = {
0d76751f JC	556	.name = "L2TP/IP",
	557	.owner = THIS_MODULE,
	558	.init = l2tp_ip_open,
	559	.close = l2tp_ip_close,
	560	.bind = l2tp_ip_bind,
	561	.connect = l2tp_ip_connect,
c51ce497	562	.disconnect = l2tp_ip_disconnect,
0d76751f JC	563	.ioctl = udp_ioctl,
	564	.destroy = l2tp_ip_destroy_sock,
	565	.setsockopt = ip_setsockopt,
	566	.getsockopt = ip_getsockopt,
	567	.sendmsg = l2tp_ip_sendmsg,
	568	.recvmsg = l2tp_ip_recvmsg,
	569	.backlog_rcv = l2tp_ip_backlog_recv,
	570	.hash = inet_hash,
	571	.unhash = inet_unhash,
	572	.obj_size = sizeof(struct l2tp_ip_sock),
	573	#ifdef CONFIG_COMPAT
	574	.compat_setsockopt = compat_ip_setsockopt,
	575	.compat_getsockopt = compat_ip_getsockopt,
	576	#endif
	577	};
	578
	579	static const struct proto_ops l2tp_ip_ops = {
	580	.family = PF_INET,
	581	.owner = THIS_MODULE,
	582	.release = inet_release,
	583	.bind = inet_bind,
	584	.connect = inet_dgram_connect,
	585	.socketpair = sock_no_socketpair,
	586	.accept = sock_no_accept,
	587	.getname = l2tp_ip_getname,
	588	.poll = datagram_poll,
	589	.ioctl = inet_ioctl,
	590	.listen = sock_no_listen,
	591	.shutdown = inet_shutdown,
	592	.setsockopt = sock_common_setsockopt,
	593	.getsockopt = sock_common_getsockopt,
	594	.sendmsg = inet_sendmsg,
	595	.recvmsg = sock_common_recvmsg,
	596	.mmap = sock_no_mmap,
	597	.sendpage = sock_no_sendpage,
	598	#ifdef CONFIG_COMPAT
	599	.compat_setsockopt = compat_sock_common_setsockopt,
	600	.compat_getsockopt = compat_sock_common_getsockopt,
	601	#endif
	602	};
	603
	604	static struct inet_protosw l2tp_ip_protosw = {
	605	.type = SOCK_DGRAM,
	606	.protocol = IPPROTO_L2TP,
	607	.prot = &l2tp_ip_prot,
	608	.ops = &l2tp_ip_ops,
0d76751f JC	609	};
	610
	611	static struct net_protocol l2tp_ip_protocol __read_mostly = {
	612	.handler = l2tp_ip_recv,
9d6ddb19	613	.netns_ok = 1,
0d76751f JC	614	};
	615
	616	static int __init l2tp_ip_init(void)
	617	{
	618	int err;
	619
a4ca44fa	620	pr_info("L2TP IP encapsulation support (L2TPv3)\n");
0d76751f JC	621
	622	err = proto_register(&l2tp_ip_prot, 1);
	623	if (err != 0)
	624	goto out;
	625
	626	err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
	627	if (err)
	628	goto out1;
	629
	630	inet_register_protosw(&l2tp_ip_protosw);
	631	return 0;
	632
	633	out1:
	634	proto_unregister(&l2tp_ip_prot);
	635	out:
	636	return err;
	637	}
	638
	639	static void __exit l2tp_ip_exit(void)
	640	{
	641	inet_unregister_protosw(&l2tp_ip_protosw);
	642	inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
	643	proto_unregister(&l2tp_ip_prot);
	644	}
	645
	646	module_init(l2tp_ip_init);
	647	module_exit(l2tp_ip_exit);
	648
	649	MODULE_LICENSE("GPL");
	650	MODULE_AUTHOR("James Chapman <[email protected]>");
	651	MODULE_DESCRIPTION("L2TP over IP");
	652	MODULE_VERSION("1.0");
e8d34a88	653
e9c54999	654	/* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
e8d34a88 MM	655	* enums
	656	*/
	657	MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 2, IPPROTO_L2TP);