l2tp: Add L2TPv3 IP encapsulation (no UDP) support
This patch adds a new L2TPIP socket family and modifies the core to
handle the case where there is no UDP header in the L2TP
packet. L2TP/IP uses IP protocol 115. Since L2TP/UDP and L2TP/IP
packets differ in layout, the datapath packet handling code needs
changes too. Userspace uses an L2TPIP socket instead of a UDP socket
when IP encapsulation is required.
We can't use raw sockets for this because the semantics of raw sockets
don't lend themselves to the socket-per-tunnel model - we need to
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
new file mode 100644
index 0000000..75bf784
--- /dev/null
+++ b/net/l2tp/l2tp_ip.c
@@ -0,0 +1,679 @@
+/*
+ * 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.
+ */
+
+#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;
+
+ __u64 tx_packets;
+ __u64 tx_bytes;
+ __u64 tx_errors;
+ __u64 rx_packets;
+ __u64 rx_bytes;
+ __u64 rx_errors;
+};
+
+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 hlist_node *node;
+ struct sock *sk;
+
+ sk_for_each_bound(sk, node, &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) &&
+#ifdef CONFIG_NET_NS
+ (sk->sk_net == net) &&
+#endif
+ !(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 sock *sk;
+ u32 session_id;
+ u32 tunnel_id;
+ unsigned char *ptr, *optr;
+ struct l2tp_session *session;
+ struct l2tp_tunnel *tunnel = NULL;
+ int length;
+ int offset;
+
+ /* 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(&init_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;
+
+ printk(KERN_DEBUG "%s: ip recv: ", tunnel->name);
+
+ offset = 0;
+ do {
+ printk(" %02X", ptr[offset]);
+ } while (++offset < length);
+
+ printk("\n");
+ }
+
+ 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(&init_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(&init_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);
+ hlist_del_init(&sk->sk_node);
+ write_unlock_bh(&l2tp_ip_lock);
+ sk_common_release(sk);
+}
+
+static void l2tp_ip_destroy_sock(struct sock *sk)
+{
+ struct sk_buff *skb;
+
+ while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
+ kfree_skb(skb);
+
+ 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;
+ int ret = -EINVAL;
+ int chk_addr_ret;
+
+ ret = -EADDRINUSE;
+ read_lock_bh(&l2tp_ip_lock);
+ if (__l2tp_ip_bind_lookup(&init_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(&init_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;
+
+ 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;
+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)
+{
+ int rc;
+ struct inet_sock *inet = inet_sk(sk);
+ struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
+ struct rtable *rt;
+ __be32 saddr;
+ int oif;
+
+ rc = -EINVAL;
+ if (addr_len < sizeof(*lsa))
+ goto out;
+
+ rc = -EAFNOSUPPORT;
+ if (lsa->l2tp_family != AF_INET)
+ goto out;
+
+ sk_dst_reset(sk);
+
+ oif = sk->sk_bound_dev_if;
+ saddr = inet->inet_saddr;
+
+ rc = -EINVAL;
+ if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
+ goto out;
+
+ rc = ip_route_connect(&rt, lsa->l2tp_addr.s_addr, saddr,
+ RT_CONN_FLAGS(sk), oif,
+ IPPROTO_L2TP,
+ 0, 0, sk, 1);
+ if (rc) {
+ if (rc == -ENETUNREACH)
+ IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
+ goto out;
+ }
+
+ rc = -ENETUNREACH;
+ if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
+ ip_rt_put(rt);
+ goto out;
+ }
+
+ l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
+
+ if (!inet->inet_saddr)
+ inet->inet_saddr = rt->rt_src;
+ if (!inet->inet_rcv_saddr)
+ inet->inet_rcv_saddr = rt->rt_src;
+ inet->inet_daddr = rt->rt_dst;
+ sk->sk_state = TCP_ESTABLISHED;
+ inet->inet_id = jiffies;
+
+ sk_dst_set(sk, &rt->u.dst);
+
+ 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);
+
+ rc = 0;
+out:
+ return rc;
+}
+
+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;
+
+ if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
+ goto drop;
+
+ nf_reset(skb);
+
+ /* 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(&init_net, 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 l2tp_ip_sock *lsa = l2tp_ip_sk(sk);
+ struct inet_sock *inet = inet_sk(sk);
+ struct ip_options *opt = inet->opt;
+ struct rtable *rt = NULL;
+ int connected = 0;
+ __be32 daddr;
+
+ if (sock_flag(sk, SOCK_DEAD))
+ return -ENOTCONN;
+
+ /* Get and verify the address. */
+ if (msg->msg_name) {
+ struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
+ if (msg->msg_namelen < sizeof(*lip))
+ return -EINVAL;
+
+ if (lip->l2tp_family != AF_INET) {
+ if (lip->l2tp_family != AF_UNSPEC)
+ return -EAFNOSUPPORT;
+ }
+
+ daddr = lip->l2tp_addr.s_addr;
+ } else {
+ if (sk->sk_state != TCP_ESTABLISHED)
+ return -EDESTADDRREQ;
+
+ 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;
+ }
+
+ if (connected)
+ rt = (struct rtable *) __sk_dst_check(sk, 0);
+
+ if (rt == NULL) {
+ /* Use correct destination address if we have options. */
+ if (opt && opt->srr)
+ daddr = opt->faddr;
+
+ {
+ struct flowi fl = { .oif = sk->sk_bound_dev_if,
+ .nl_u = { .ip4_u = {
+ .daddr = daddr,
+ .saddr = inet->inet_saddr,
+ .tos = RT_CONN_FLAGS(sk) } },
+ .proto = sk->sk_protocol,
+ .flags = inet_sk_flowi_flags(sk),
+ .uli_u = { .ports = {
+ .sport = inet->inet_sport,
+ .dport = inet->inet_dport } } };
+
+ /* If this fails, retransmit mechanism of transport layer will
+ * keep trying until route appears or the connection times
+ * itself out.
+ */
+ security_sk_classify_flow(sk, &fl);
+ if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0))
+ goto no_route;
+ }
+ sk_setup_caps(sk, &rt->u.dst);
+ }
+ skb_dst_set(skb, dst_clone(&rt->u.dst));
+
+ /* Queue the packet to IP for output */
+ rc = ip_queue_xmit(skb, 0);
+
+error:
+ /* Update stats */
+ if (rc >= 0) {
+ lsa->tx_packets++;
+ lsa->tx_bytes += len;
+ rc = len;
+ } else {
+ lsa->tx_errors++;
+ }
+
+ return rc;
+
+no_route:
+ IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
+ kfree_skb(skb);
+ return -EHOSTUNREACH;
+}
+
+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);
+ struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
+ size_t copied = 0;
+ int err = -EOPNOTSUPP;
+ struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
+ struct sk_buff *skb;
+
+ if (flags & MSG_OOB)
+ goto out;
+
+ if (addr_len)
+ *addr_len = sizeof(*sin);
+
+ 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));
+ }
+ if (inet->cmsg_flags)
+ ip_cmsg_recv(msg, skb);
+ if (flags & MSG_TRUNC)
+ copied = skb->len;
+done:
+ skb_free_datagram(sk, skb);
+out:
+ if (err) {
+ lsk->rx_errors++;
+ return err;
+ }
+
+ lsk->rx_packets++;
+ lsk->rx_bytes += copied;
+
+ return copied;
+}
+
+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 = udp_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,
+ .no_check = 0,
+};
+
+static struct net_protocol l2tp_ip_protocol __read_mostly = {
+ .handler = l2tp_ip_recv,
+};
+
+static int __init l2tp_ip_init(void)
+{
+ int err;
+
+ printk(KERN_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 <jchapman@katalix.com>");
+MODULE_DESCRIPTION("L2TP over IP");
+MODULE_VERSION("1.0");
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, SOCK_DGRAM, IPPROTO_L2TP);