2 * L2TPv3 IP encapsulation support for IPv6
4 * Copyright (c) 2012 Katalix Systems Ltd
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.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
21 #include <linux/in6.h>
26 #include <net/inet_common.h>
27 #include <net/tcp_states.h>
28 #include <net/protocol.h>
31 #include <net/transp_v6.h>
32 #include <net/addrconf.h>
33 #include <net/ip6_route.h>
35 #include "l2tp_core.h"
37 struct l2tp_ip6_sock {
38 /* inet_sock has to be the first member of l2tp_ip6_sock */
39 struct inet_sock inet;
44 /* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
46 struct ipv6_pinfo inet6;
49 static DEFINE_RWLOCK(l2tp_ip6_lock);
50 static struct hlist_head l2tp_ip6_table;
51 static struct hlist_head l2tp_ip6_bind_table;
53 static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
55 return (struct l2tp_ip6_sock *)sk;
58 static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
59 struct in6_addr *laddr,
60 const struct in6_addr *raddr,
61 int dif, u32 tunnel_id)
65 sk_for_each_bound(sk, &l2tp_ip6_bind_table) {
66 const struct in6_addr *sk_laddr = inet6_rcv_saddr(sk);
67 const struct in6_addr *sk_raddr = &sk->sk_v6_daddr;
68 struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
73 if ((l2tp->conn_id == tunnel_id) &&
74 net_eq(sock_net(sk), net) &&
75 (!sk_laddr || ipv6_addr_any(sk_laddr) || ipv6_addr_equal(sk_laddr, laddr)) &&
76 (!raddr || ipv6_addr_any(sk_raddr) || ipv6_addr_equal(sk_raddr, raddr)) &&
77 (!sk->sk_bound_dev_if || !dif ||
78 sk->sk_bound_dev_if == dif))
87 /* When processing receive frames, there are two cases to
88 * consider. Data frames consist of a non-zero session-id and an
89 * optional cookie. Control frames consist of a regular L2TP header
90 * preceded by 32-bits of zeros.
92 * L2TPv3 Session Header Over IP
95 * 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
96 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
98 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
99 * | Cookie (optional, maximum 64 bits)...
100 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
104 * L2TPv3 Control Message Header Over IP
107 * 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
108 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
109 * | (32 bits of zeros) |
110 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
111 * |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
112 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
113 * | Control Connection ID |
114 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
116 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
118 * All control frames are passed to userspace.
120 static int l2tp_ip6_recv(struct sk_buff *skb)
122 struct net *net = dev_net(skb->dev);
126 unsigned char *ptr, *optr;
127 struct l2tp_session *session;
128 struct l2tp_tunnel *tunnel = NULL;
132 if (!pskb_may_pull(skb, 4))
135 /* Point to L2TP header */
136 optr = ptr = skb->data;
137 session_id = ntohl(*((__be32 *) ptr));
140 /* RFC3931: L2TP/IP packets have the first 4 bytes containing
141 * the session_id. If it is 0, the packet is a L2TP control
142 * frame and the session_id value can be discarded.
144 if (session_id == 0) {
149 /* Ok, this is a data packet. Lookup the session. */
150 session = l2tp_session_get(net, NULL, session_id, true);
154 tunnel = session->tunnel;
158 /* Trace packet contents, if enabled */
159 if (tunnel->debug & L2TP_MSG_DATA) {
160 length = min(32u, skb->len);
161 if (!pskb_may_pull(skb, length))
164 /* Point to L2TP header */
165 optr = ptr = skb->data;
167 pr_debug("%s: ip recv\n", tunnel->name);
168 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
171 if (l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr))
174 l2tp_recv_common(session, skb, ptr, optr, 0, skb->len,
175 tunnel->recv_payload_hook);
176 l2tp_session_dec_refcount(session);
181 /* Get the tunnel_id from the L2TP header */
182 if (!pskb_may_pull(skb, 12))
185 if ((skb->data[0] & 0xc0) != 0xc0)
188 tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
191 read_lock_bh(&l2tp_ip6_lock);
192 sk = __l2tp_ip6_bind_lookup(net, &iph->daddr, &iph->saddr,
193 inet6_iif(skb), tunnel_id);
195 read_unlock_bh(&l2tp_ip6_lock);
199 read_unlock_bh(&l2tp_ip6_lock);
201 if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
206 return sk_receive_skb(sk, skb, 1);
210 session->deref(session);
211 l2tp_session_dec_refcount(session);
222 static int l2tp_ip6_hash(struct sock *sk)
224 if (sk_unhashed(sk)) {
225 write_lock_bh(&l2tp_ip6_lock);
226 sk_add_node(sk, &l2tp_ip6_table);
227 write_unlock_bh(&l2tp_ip6_lock);
232 static void l2tp_ip6_unhash(struct sock *sk)
236 write_lock_bh(&l2tp_ip6_lock);
237 sk_del_node_init(sk);
238 write_unlock_bh(&l2tp_ip6_lock);
241 static int l2tp_ip6_open(struct sock *sk)
243 /* Prevent autobind. We don't have ports. */
244 inet_sk(sk)->inet_num = IPPROTO_L2TP;
250 static void l2tp_ip6_close(struct sock *sk, long timeout)
252 write_lock_bh(&l2tp_ip6_lock);
253 hlist_del_init(&sk->sk_bind_node);
254 sk_del_node_init(sk);
255 write_unlock_bh(&l2tp_ip6_lock);
257 sk_common_release(sk);
260 static void l2tp_ip6_destroy_sock(struct sock *sk)
262 struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
265 ip6_flush_pending_frames(sk);
269 l2tp_tunnel_closeall(tunnel);
273 inet6_destroy_sock(sk);
276 static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
278 struct inet_sock *inet = inet_sk(sk);
279 struct ipv6_pinfo *np = inet6_sk(sk);
280 struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
281 struct net *net = sock_net(sk);
287 if (addr->l2tp_family != AF_INET6)
289 if (addr_len < sizeof(*addr))
292 addr_type = ipv6_addr_type(&addr->l2tp_addr);
294 /* l2tp_ip6 sockets are IPv6 only */
295 if (addr_type == IPV6_ADDR_MAPPED)
296 return -EADDRNOTAVAIL;
298 /* L2TP is point-point, not multicast */
299 if (addr_type & IPV6_ADDR_MULTICAST)
300 return -EADDRNOTAVAIL;
305 if (!sock_flag(sk, SOCK_ZAPPED))
308 if (sk->sk_state != TCP_CLOSE)
311 bound_dev_if = sk->sk_bound_dev_if;
313 /* Check if the address belongs to the host. */
315 if (addr_type != IPV6_ADDR_ANY) {
316 struct net_device *dev = NULL;
318 if (addr_type & IPV6_ADDR_LINKLOCAL) {
319 if (addr->l2tp_scope_id)
320 bound_dev_if = addr->l2tp_scope_id;
322 /* Binding to link-local address requires an
329 dev = dev_get_by_index_rcu(sock_net(sk), bound_dev_if);
334 /* ipv4 addr of the socket is invalid. Only the
335 * unspecified and mapped address have a v4 equivalent.
337 v4addr = LOOPBACK4_IPV6;
338 err = -EADDRNOTAVAIL;
339 if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
344 write_lock_bh(&l2tp_ip6_lock);
345 if (__l2tp_ip6_bind_lookup(net, &addr->l2tp_addr, NULL, bound_dev_if,
346 addr->l2tp_conn_id)) {
347 write_unlock_bh(&l2tp_ip6_lock);
352 inet->inet_saddr = v4addr;
353 inet->inet_rcv_saddr = v4addr;
354 sk->sk_bound_dev_if = bound_dev_if;
355 sk->sk_v6_rcv_saddr = addr->l2tp_addr;
356 np->saddr = addr->l2tp_addr;
358 l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
360 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
361 sk_del_node_init(sk);
362 write_unlock_bh(&l2tp_ip6_lock);
364 sock_reset_flag(sk, SOCK_ZAPPED);
376 static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
379 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
380 struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
381 struct in6_addr *daddr;
385 if (addr_len < sizeof(*lsa))
388 if (usin->sin6_family != AF_INET6)
391 addr_type = ipv6_addr_type(&usin->sin6_addr);
392 if (addr_type & IPV6_ADDR_MULTICAST)
395 if (addr_type & IPV6_ADDR_MAPPED) {
396 daddr = &usin->sin6_addr;
397 if (ipv4_is_multicast(daddr->s6_addr32[3]))
403 /* Must bind first - autobinding does not work */
404 if (sock_flag(sk, SOCK_ZAPPED)) {
409 rc = __ip6_datagram_connect(sk, uaddr, addr_len);
413 l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
415 write_lock_bh(&l2tp_ip6_lock);
416 hlist_del_init(&sk->sk_bind_node);
417 sk_add_bind_node(sk, &l2tp_ip6_bind_table);
418 write_unlock_bh(&l2tp_ip6_lock);
426 static int l2tp_ip6_disconnect(struct sock *sk, int flags)
428 if (sock_flag(sk, SOCK_ZAPPED))
431 return __udp_disconnect(sk, flags);
434 static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
435 int *uaddr_len, int peer)
437 struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
438 struct sock *sk = sock->sk;
439 struct ipv6_pinfo *np = inet6_sk(sk);
440 struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
442 lsa->l2tp_family = AF_INET6;
443 lsa->l2tp_flowinfo = 0;
444 lsa->l2tp_scope_id = 0;
445 lsa->l2tp_unused = 0;
447 if (!lsk->peer_conn_id)
449 lsa->l2tp_conn_id = lsk->peer_conn_id;
450 lsa->l2tp_addr = sk->sk_v6_daddr;
452 lsa->l2tp_flowinfo = np->flow_label;
454 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
455 lsa->l2tp_addr = np->saddr;
457 lsa->l2tp_addr = sk->sk_v6_rcv_saddr;
459 lsa->l2tp_conn_id = lsk->conn_id;
461 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
462 lsa->l2tp_scope_id = sk->sk_bound_dev_if;
463 *uaddr_len = sizeof(*lsa);
467 static int l2tp_ip6_backlog_recv(struct sock *sk, struct sk_buff *skb)
471 /* Charge it to the socket, dropping if the queue is full. */
472 rc = sock_queue_rcv_skb(sk, skb);
479 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS);
484 static int l2tp_ip6_push_pending_frames(struct sock *sk)
487 __be32 *transhdr = NULL;
490 skb = skb_peek(&sk->sk_write_queue);
494 transhdr = (__be32 *)skb_transport_header(skb);
497 err = ip6_push_pending_frames(sk);
503 /* Userspace will call sendmsg() on the tunnel socket to send L2TP
506 static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
508 struct ipv6_txoptions opt_space;
509 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
510 struct in6_addr *daddr, *final_p, final;
511 struct ipv6_pinfo *np = inet6_sk(sk);
512 struct ipv6_txoptions *opt_to_free = NULL;
513 struct ipv6_txoptions *opt = NULL;
514 struct ip6_flowlabel *flowlabel = NULL;
515 struct dst_entry *dst = NULL;
517 struct sockcm_cookie sockc_unused = {0};
518 struct ipcm6_cookie ipc6;
519 int addr_len = msg->msg_namelen;
520 int transhdrlen = 4; /* zero session-id */
521 int ulen = len + transhdrlen;
524 /* Rough check on arithmetic overflow,
525 better check is made in ip6_append_data().
530 /* Mirror BSD error message compatibility */
531 if (msg->msg_flags & MSG_OOB)
535 * Get and verify the address.
537 memset(&fl6, 0, sizeof(fl6));
539 fl6.flowi6_mark = sk->sk_mark;
546 if (addr_len < SIN6_LEN_RFC2133)
549 if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
550 return -EAFNOSUPPORT;
552 daddr = &lsa->l2tp_addr;
554 fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
555 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
556 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
557 if (flowlabel == NULL)
563 * Otherwise it will be difficult to maintain
566 if (sk->sk_state == TCP_ESTABLISHED &&
567 ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
568 daddr = &sk->sk_v6_daddr;
570 if (addr_len >= sizeof(struct sockaddr_in6) &&
571 lsa->l2tp_scope_id &&
572 ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
573 fl6.flowi6_oif = lsa->l2tp_scope_id;
575 if (sk->sk_state != TCP_ESTABLISHED)
576 return -EDESTADDRREQ;
578 daddr = &sk->sk_v6_daddr;
579 fl6.flowlabel = np->flow_label;
582 if (fl6.flowi6_oif == 0)
583 fl6.flowi6_oif = sk->sk_bound_dev_if;
585 if (msg->msg_controllen) {
587 memset(opt, 0, sizeof(struct ipv6_txoptions));
588 opt->tot_len = sizeof(struct ipv6_txoptions);
591 err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6,
594 fl6_sock_release(flowlabel);
597 if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
598 flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
599 if (flowlabel == NULL)
602 if (!(opt->opt_nflen|opt->opt_flen))
611 opt = fl6_merge_options(&opt_space, flowlabel, opt);
612 opt = ipv6_fixup_options(&opt_space, opt);
615 fl6.flowi6_proto = sk->sk_protocol;
616 if (!ipv6_addr_any(daddr))
619 fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
620 if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
621 fl6.saddr = np->saddr;
623 final_p = fl6_update_dst(&fl6, opt, &final);
625 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
626 fl6.flowi6_oif = np->mcast_oif;
627 else if (!fl6.flowi6_oif)
628 fl6.flowi6_oif = np->ucast_oif;
630 security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
633 ipc6.tclass = np->tclass;
635 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
637 dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
644 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
646 if (ipc6.dontfrag < 0)
647 ipc6.dontfrag = np->dontfrag;
649 if (msg->msg_flags & MSG_CONFIRM)
654 err = ip6_append_data(sk, ip_generic_getfrag, msg,
655 ulen, transhdrlen, &ipc6,
656 &fl6, (struct rt6_info *)dst,
657 msg->msg_flags, &sockc_unused);
659 ip6_flush_pending_frames(sk);
660 else if (!(msg->msg_flags & MSG_MORE))
661 err = l2tp_ip6_push_pending_frames(sk);
666 fl6_sock_release(flowlabel);
667 txopt_put(opt_to_free);
669 return err < 0 ? err : len;
673 if (!(msg->msg_flags & MSG_PROBE) || len)
674 goto back_from_confirm;
679 static int l2tp_ip6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
680 int noblock, int flags, int *addr_len)
682 struct ipv6_pinfo *np = inet6_sk(sk);
683 DECLARE_SOCKADDR(struct sockaddr_l2tpip6 *, lsa, msg->msg_name);
685 int err = -EOPNOTSUPP;
691 if (flags & MSG_ERRQUEUE)
692 return ipv6_recv_error(sk, msg, len, addr_len);
694 skb = skb_recv_datagram(sk, flags, noblock, &err);
700 msg->msg_flags |= MSG_TRUNC;
704 err = skb_copy_datagram_msg(skb, 0, msg, copied);
708 sock_recv_timestamp(msg, sk, skb);
710 /* Copy the address. */
712 lsa->l2tp_family = AF_INET6;
713 lsa->l2tp_unused = 0;
714 lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
715 lsa->l2tp_flowinfo = 0;
716 lsa->l2tp_scope_id = 0;
717 lsa->l2tp_conn_id = 0;
718 if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
719 lsa->l2tp_scope_id = inet6_iif(skb);
720 *addr_len = sizeof(*lsa);
724 ip6_datagram_recv_ctl(sk, msg, skb);
726 if (flags & MSG_TRUNC)
729 skb_free_datagram(sk, skb);
731 return err ? err : copied;
734 static struct proto l2tp_ip6_prot = {
736 .owner = THIS_MODULE,
737 .init = l2tp_ip6_open,
738 .close = l2tp_ip6_close,
739 .bind = l2tp_ip6_bind,
740 .connect = l2tp_ip6_connect,
741 .disconnect = l2tp_ip6_disconnect,
743 .destroy = l2tp_ip6_destroy_sock,
744 .setsockopt = ipv6_setsockopt,
745 .getsockopt = ipv6_getsockopt,
746 .sendmsg = l2tp_ip6_sendmsg,
747 .recvmsg = l2tp_ip6_recvmsg,
748 .backlog_rcv = l2tp_ip6_backlog_recv,
749 .hash = l2tp_ip6_hash,
750 .unhash = l2tp_ip6_unhash,
751 .obj_size = sizeof(struct l2tp_ip6_sock),
753 .compat_setsockopt = compat_ipv6_setsockopt,
754 .compat_getsockopt = compat_ipv6_getsockopt,
758 static const struct proto_ops l2tp_ip6_ops = {
760 .owner = THIS_MODULE,
761 .release = inet6_release,
763 .connect = inet_dgram_connect,
764 .socketpair = sock_no_socketpair,
765 .accept = sock_no_accept,
766 .getname = l2tp_ip6_getname,
767 .poll = datagram_poll,
768 .ioctl = inet6_ioctl,
769 .listen = sock_no_listen,
770 .shutdown = inet_shutdown,
771 .setsockopt = sock_common_setsockopt,
772 .getsockopt = sock_common_getsockopt,
773 .sendmsg = inet_sendmsg,
774 .recvmsg = sock_common_recvmsg,
775 .mmap = sock_no_mmap,
776 .sendpage = sock_no_sendpage,
778 .compat_setsockopt = compat_sock_common_setsockopt,
779 .compat_getsockopt = compat_sock_common_getsockopt,
783 static struct inet_protosw l2tp_ip6_protosw = {
785 .protocol = IPPROTO_L2TP,
786 .prot = &l2tp_ip6_prot,
787 .ops = &l2tp_ip6_ops,
790 static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
791 .handler = l2tp_ip6_recv,
794 static int __init l2tp_ip6_init(void)
798 pr_info("L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
800 err = proto_register(&l2tp_ip6_prot, 1);
804 err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
808 inet6_register_protosw(&l2tp_ip6_protosw);
812 proto_unregister(&l2tp_ip6_prot);
817 static void __exit l2tp_ip6_exit(void)
819 inet6_unregister_protosw(&l2tp_ip6_protosw);
820 inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
821 proto_unregister(&l2tp_ip6_prot);
824 module_init(l2tp_ip6_init);
825 module_exit(l2tp_ip6_exit);
827 MODULE_LICENSE("GPL");
828 MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
829 MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
830 MODULE_VERSION("1.0");
832 /* Use the value of SOCK_DGRAM (2) directory, because __stringify doesn't like
835 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 2, IPPROTO_L2TP);
836 MODULE_ALIAS_NET_PF_PROTO(PF_INET6, IPPROTO_L2TP);