[PATCH 00/10] l2tp: misc fixes and add L2TPv3 IP encap over IPv6

[PATCH 00/10] l2tp: misc fixes and add L2TPv3 IP encap over IPv6

[James Chapman]

This patch series includes several L2TP fixes / cleanups and adds
L2TPv3 IP encapsulation support for IPv6.

Patches 4-10 depend on Benjamin LaHaise's L2TP UDP IPv6 patches which
have already been submitted for review. Patches 1-3 are not IPv6
related so can be reviewed / applied now.

  1. l2tp: fix locking of 64-bit counters for smp
  2. l2tp: Use ip4_datagram_connect() in l2tp_ip_connect()
  3. l2tp: remove unused stats from l2tp_ip socket
  4. pppox: Replace __attribute__((packed)) in if_pppox.h
  5. l2tp: pppol2tp_connect() handles ipv6 sockaddr variants
  6. l2tp: show IPv6 addresses in l2tp debugfs file
  7. l2tp: netlink api for l2tpv3 ipv6 unmanaged tunnels
  8. ipv6: export ipv6 functions for use by other protocols
  9. l2tp: introduce L2TPv3 IP encapsulation support for IPv6
 10. l2tp: let iproute2 create L2TPv3 IP tunnels using IPv6

A patch for iproute2 to add support for unmanaged L2TPv3 ethernet
tunnels over IPv6 will be submitted separately.

Chris Elston (4):
  l2tp: show IPv6 addresses in l2tp debugfs file
  l2tp: netlink api for l2tpv3 ipv6 unmanaged tunnels
  ipv6: Export ipv6 functions for use by other protocols
  l2tp: introduce L2TPv3 IP encapsulation support for IPv6

James Chapman (6):
  l2tp: fix locking of 64-bit counters for smp
  l2tp: Use ip4_datagram_connect() in l2tp_ip_connect()
  l2tp: remove unused stats from l2tp_ip socket
  pppox: Replace __attribute__((packed)) in if_pppox.h
  l2tp: pppol2tp_connect() handles ipv6 sockaddr variants
  l2tp: let iproute2 create L2TPv3 IP tunnels using IPv6

 include/linux/if_pppox.h |   12 +-
 include/linux/l2tp.h     |   19 ++
 net/ipv6/datagram.c      |    4 +
 net/ipv6/exthdrs.c       |    1 +
 net/ipv6/ip6_flowlabel.c |    1 +
 net/ipv6/ip6_output.c    |    3 +
 net/l2tp/Makefile        |    3 +
 net/l2tp/l2tp_core.c     |  215 ++++++++++---
 net/l2tp/l2tp_core.h     |    5 +
 net/l2tp/l2tp_debugfs.c  |    8 +
 net/l2tp/l2tp_ip.c       |   86 +-----
 net/l2tp/l2tp_ip6.c      |  792 ++++++++++++++++++++++++++++++++++++++++++++++
 net/l2tp/l2tp_netlink.c  |  110 ++++++--
 net/l2tp/l2tp_ppp.c      |   36 ++-
 14 files changed, 1133 insertions(+), 162 deletions(-)
 create mode 100644 net/l2tp/l2tp_ip6.c

[PATCH 01/10] l2tp: fix locking of 64-bit counters for smp

[James Chapman]

L2TP uses 64-bit counters but since these are not updated atomically,
we need to make them safe for smp. This patch addresses that.

Signed-off-by: James Chapman <jchapman@katalix.com>
---
 net/l2tp/l2tp_core.c    |   75 +++++++++++++++++++++++++++++++++++------------
 net/l2tp/l2tp_core.h    |    1 +
 net/l2tp/l2tp_netlink.c |   62 ++++++++++++++++++++++++++++----------
 3 files changed, 103 insertions(+), 35 deletions(-)

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 8cd5f4b..5e27c05 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -329,8 +329,10 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk
 	struct sk_buff *skbp;
 	struct sk_buff *tmp;
 	u32 ns = L2TP_SKB_CB(skb)->ns;
+	struct l2tp_stats *sstats;
 
 	spin_lock_bh(&session->reorder_q.lock);
+	sstats = &session->stats;
 	skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
 		if (L2TP_SKB_CB(skbp)->ns > ns) {
 			__skb_queue_before(&session->reorder_q, skbp, skb);
@@ -338,7 +340,9 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk
 			       "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
 			       session->name, ns, L2TP_SKB_CB(skbp)->ns,
 			       skb_queue_len(&session->reorder_q));
-			session->stats.rx_oos_packets++;
+			u64_stats_update_begin(&sstats->syncp);
+			sstats->rx_oos_packets++;
+			u64_stats_update_end(&sstats->syncp);
 			goto out;
 		}
 	}
@@ -355,16 +359,23 @@ static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *
 {
 	struct l2tp_tunnel *tunnel = session->tunnel;
 	int length = L2TP_SKB_CB(skb)->length;
+	struct l2tp_stats *tstats, *sstats;
 
 	/* We're about to requeue the skb, so return resources
 	 * to its current owner (a socket receive buffer).
 	 */
 	skb_orphan(skb);
 
-	tunnel->stats.rx_packets++;
-	tunnel->stats.rx_bytes += length;
-	session->stats.rx_packets++;
-	session->stats.rx_bytes += length;
+	tstats = &tunnel->stats;
+	u64_stats_update_begin(&tstats->syncp);
+	sstats = &session->stats;
+	u64_stats_update_begin(&sstats->syncp);
+	tstats->rx_packets++;
+	tstats->rx_bytes += length;
+	sstats->rx_packets++;
+	sstats->rx_bytes += length;
+	u64_stats_update_end(&tstats->syncp);
+	u64_stats_update_end(&sstats->syncp);
 
 	if (L2TP_SKB_CB(skb)->has_seq) {
 		/* Bump our Nr */
@@ -395,6 +406,7 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
 {
 	struct sk_buff *skb;
 	struct sk_buff *tmp;
+	struct l2tp_stats *sstats;
 
 	/* If the pkt at the head of the queue has the nr that we
 	 * expect to send up next, dequeue it and any other
@@ -402,10 +414,13 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
 	 */
 start:
 	spin_lock_bh(&session->reorder_q.lock);
+	sstats = &session->stats;
 	skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
 		if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
-			session->stats.rx_seq_discards++;
-			session->stats.rx_errors++;
+			u64_stats_update_begin(&sstats->syncp);
+			sstats->rx_seq_discards++;
+			sstats->rx_errors++;
+			u64_stats_update_end(&sstats->syncp);
 			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
 			       "%s: oos pkt %u len %d discarded (too old), "
 			       "waiting for %u, reorder_q_len=%d\n",
@@ -557,6 +572,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 	struct l2tp_tunnel *tunnel = session->tunnel;
 	int offset;
 	u32 ns, nr;
+	struct l2tp_stats *sstats = &session->stats;
 
 	/* The ref count is increased since we now hold a pointer to
 	 * the session. Take care to decrement the refcnt when exiting
@@ -572,7 +588,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 			PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
 			       "%s: cookie mismatch (%u/%u). Discarding.\n",
 			       tunnel->name, tunnel->tunnel_id, session->session_id);
-			session->stats.rx_cookie_discards++;
+			u64_stats_update_begin(&sstats->syncp);
+			sstats->rx_cookie_discards++;
+			u64_stats_update_end(&sstats->syncp);
 			goto discard;
 		}
 		ptr += session->peer_cookie_len;
@@ -641,7 +659,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
 			       "%s: recv data has no seq numbers when required. "
 			       "Discarding\n", session->name);
-			session->stats.rx_seq_discards++;
+			u64_stats_update_begin(&sstats->syncp);
+			sstats->rx_seq_discards++;
+			u64_stats_update_end(&sstats->syncp);
 			goto discard;
 		}
 
@@ -660,7 +680,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
 			       "%s: recv data has no seq numbers when required. "
 			       "Discarding\n", session->name);
-			session->stats.rx_seq_discards++;
+			u64_stats_update_begin(&sstats->syncp);
+			sstats->rx_seq_discards++;
+			u64_stats_update_end(&sstats->syncp);
 			goto discard;
 		}
 	}
@@ -714,7 +736,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 			 * packets
 			 */
 			if (L2TP_SKB_CB(skb)->ns != session->nr) {
-				session->stats.rx_seq_discards++;
+				u64_stats_update_begin(&sstats->syncp);
+				sstats->rx_seq_discards++;
+				u64_stats_update_end(&sstats->syncp);
 				PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
 				       "%s: oos pkt %u len %d discarded, "
 				       "waiting for %u, reorder_q_len=%d\n",
@@ -741,7 +765,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 	return;
 
 discard:
-	session->stats.rx_errors++;
+	u64_stats_update_begin(&sstats->syncp);
+	sstats->rx_errors++;
+	u64_stats_update_end(&sstats->syncp);
 	kfree_skb(skb);
 
 	if (session->deref)
@@ -767,6 +793,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 	int offset;
 	u16 version;
 	int length;
+	struct l2tp_stats *tstats;
 
 	if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
 		goto discard_bad_csum;
@@ -859,7 +886,10 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 discard_bad_csum:
 	LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
 	UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
-	tunnel->stats.rx_errors++;
+	tstats = &tunnel->stats;
+	u64_stats_update_begin(&tstats->syncp);
+	tstats->rx_errors++;
+	u64_stats_update_end(&tstats->syncp);
 	kfree_skb(skb);
 
 	return 0;
@@ -985,6 +1015,7 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
 	struct l2tp_tunnel *tunnel = session->tunnel;
 	unsigned int len = skb->len;
 	int error;
+	struct l2tp_stats *tstats, *sstats;
 
 	/* Debug */
 	if (session->send_seq)
@@ -1021,15 +1052,21 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
 		error = ip_queue_xmit(skb, fl);
 
 	/* Update stats */
+	tstats = &tunnel->stats;
+	u64_stats_update_begin(&tstats->syncp);
+	sstats = &session->stats;
+	u64_stats_update_begin(&sstats->syncp);
 	if (error >= 0) {
-		tunnel->stats.tx_packets++;
-		tunnel->stats.tx_bytes += len;
-		session->stats.tx_packets++;
-		session->stats.tx_bytes += len;
+		tstats->tx_packets++;
+		tstats->tx_bytes += len;
+		sstats->tx_packets++;
+		sstats->tx_bytes += len;
 	} else {
-		tunnel->stats.tx_errors++;
-		session->stats.tx_errors++;
+		tstats->tx_errors++;
+		sstats->tx_errors++;
 	}
+	u64_stats_update_end(&tstats->syncp);
+	u64_stats_update_end(&sstats->syncp);
 
 	return 0;
 }
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index 09e4a38..a8c943b 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -45,6 +45,7 @@ struct l2tp_stats {
 	u64			rx_oos_packets;
 	u64			rx_errors;
 	u64			rx_cookie_discards;
+	struct u64_stats_sync	syncp;
 };
 
 struct l2tp_tunnel;
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index bc8c334..1dbb977 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -225,6 +225,8 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
 	struct nlattr *nest;
 	struct sock *sk = NULL;
 	struct inet_sock *inet;
+	struct l2tp_stats stats;
+	unsigned int start;
 
 	hdr = genlmsg_put(skb, pid, seq, &l2tp_nl_family, flags,
 			  L2TP_CMD_TUNNEL_GET);
@@ -242,16 +244,28 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
 	if (nest == NULL)
 		goto nla_put_failure;
 
-	if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, tunnel->stats.tx_packets) ||
-	    nla_put_u64(skb, L2TP_ATTR_TX_BYTES, tunnel->stats.tx_bytes) ||
-	    nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, tunnel->stats.tx_errors) ||
-	    nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, tunnel->stats.rx_packets) ||
-	    nla_put_u64(skb, L2TP_ATTR_RX_BYTES, tunnel->stats.rx_bytes) ||
+	do {
+		start = u64_stats_fetch_begin(&tunnel->stats.syncp);
+		stats.tx_packets = tunnel->stats.tx_packets;
+		stats.tx_bytes = tunnel->stats.tx_bytes;
+		stats.tx_errors = tunnel->stats.tx_errors;
+		stats.rx_packets = tunnel->stats.rx_packets;
+		stats.rx_bytes = tunnel->stats.rx_bytes;
+		stats.rx_errors = tunnel->stats.rx_errors;
+		stats.rx_seq_discards = tunnel->stats.rx_seq_discards;
+		stats.rx_oos_packets = tunnel->stats.rx_oos_packets;
+	} while (u64_stats_fetch_retry(&tunnel->stats.syncp, start));
+
+	if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, stats.tx_packets) ||
+	    nla_put_u64(skb, L2TP_ATTR_TX_BYTES, stats.tx_bytes) ||
+	    nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, stats.tx_errors) ||
+	    nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, stats.rx_packets) ||
+	    nla_put_u64(skb, L2TP_ATTR_RX_BYTES, stats.rx_bytes) ||
 	    nla_put_u64(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
-			tunnel->stats.rx_seq_discards) ||
+			stats.rx_seq_discards) ||
 	    nla_put_u64(skb, L2TP_ATTR_RX_OOS_PACKETS,
-			tunnel->stats.rx_oos_packets) ||
-	    nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, tunnel->stats.rx_errors))
+			stats.rx_oos_packets) ||
+	    nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, stats.rx_errors))
 		goto nla_put_failure;
 	nla_nest_end(skb, nest);
 
@@ -563,6 +577,8 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 pid, u32 seq, int flags
 	struct nlattr *nest;
 	struct l2tp_tunnel *tunnel = session->tunnel;
 	struct sock *sk = NULL;
+	struct l2tp_stats stats;
+	unsigned int start;
 
 	sk = tunnel->sock;
 
@@ -600,19 +616,33 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 pid, u32 seq, int flags
 	    (session->reorder_timeout &&
 	     nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT, session->reorder_timeout)))
 		goto nla_put_failure;
+
 	nest = nla_nest_start(skb, L2TP_ATTR_STATS);
 	if (nest == NULL)
 		goto nla_put_failure;
-	if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, session->stats.tx_packets) ||
-	    nla_put_u64(skb, L2TP_ATTR_TX_BYTES, session->stats.tx_bytes) ||
-	    nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, session->stats.tx_errors) ||
-	    nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, session->stats.rx_packets) ||
-	    nla_put_u64(skb, L2TP_ATTR_RX_BYTES, session->stats.rx_bytes) ||
+
+	do {
+		start = u64_stats_fetch_begin(&session->stats.syncp);
+		stats.tx_packets = session->stats.tx_packets;
+		stats.tx_bytes = session->stats.tx_bytes;
+		stats.tx_errors = session->stats.tx_errors;
+		stats.rx_packets = session->stats.rx_packets;
+		stats.rx_bytes = session->stats.rx_bytes;
+		stats.rx_errors = session->stats.rx_errors;
+		stats.rx_seq_discards = session->stats.rx_seq_discards;
+		stats.rx_oos_packets = session->stats.rx_oos_packets;
+	} while (u64_stats_fetch_retry(&session->stats.syncp, start));
+
+	if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, stats.tx_packets) ||
+	    nla_put_u64(skb, L2TP_ATTR_TX_BYTES, stats.tx_bytes) ||
+	    nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, stats.tx_errors) ||
+	    nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, stats.rx_packets) ||
+	    nla_put_u64(skb, L2TP_ATTR_RX_BYTES, stats.rx_bytes) ||
 	    nla_put_u64(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
-			session->stats.rx_seq_discards) ||
+			stats.rx_seq_discards) ||
 	    nla_put_u64(skb, L2TP_ATTR_RX_OOS_PACKETS,
-			session->stats.rx_oos_packets) ||
-	    nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, session->stats.rx_errors))
+			stats.rx_oos_packets) ||
+	    nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, stats.rx_errors))
 		goto nla_put_failure;
 	nla_nest_end(skb, nest);
 
-- 
1.7.0.4

[PATCH 02/10] l2tp: Use ip4_datagram_connect() in l2tp_ip_connect()

[James Chapman]

Cleanup the l2tp_ip code to make use of an existing ipv4 support function.

Signed-off-by: James Chapman <jchapman@katalix.com>
---
 net/l2tp/l2tp_ip.c |   54 ++++++---------------------------------------------
 1 files changed, 7 insertions(+), 47 deletions(-)

diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 585d93e..5162592 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -299,67 +299,27 @@ static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len
 {
 	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
 	struct inet_sock *inet = inet_sk(sk);
-	struct flowi4 *fl4;
-	struct rtable *rt;
-	__be32 saddr;
-	int oif, rc;
+	int rc;
 
-	rc = -EINVAL;
 	if (addr_len < sizeof(*lsa))
-		goto out;
+		return -EINVAL;
 
-	rc = -EAFNOSUPPORT;
-	if (lsa->l2tp_family != AF_INET)
-		goto out;
-
-	lock_sock(sk);
-
-	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;
+		return -EINVAL;
 
-	fl4 = &inet->cork.fl.u.ip4;
-	rt = ip_route_connect(fl4, lsa->l2tp_addr.s_addr, saddr,
-			      RT_CONN_FLAGS(sk), oif,
-			      IPPROTO_L2TP,
-			      0, 0, sk, true);
-	if (IS_ERR(rt)) {
-		rc = PTR_ERR(rt);
-		if (rc == -ENETUNREACH)
-			IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
-		goto out;
-	}
+	rc = ip4_datagram_connect(sk, uaddr, addr_len);
+	if (rc < 0)
+		return rc;
 
-	rc = -ENETUNREACH;
-	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
-		ip_rt_put(rt);
-		goto out;
-	}
+	lock_sock(sk);
 
 	l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
 
-	if (!inet->inet_saddr)
-		inet->inet_saddr = fl4->saddr;
-	if (!inet->inet_rcv_saddr)
-		inet->inet_rcv_saddr = fl4->saddr;
-	inet->inet_daddr = fl4->daddr;
-	sk->sk_state = TCP_ESTABLISHED;
-	inet->inet_id = jiffies;
-
-	sk_dst_set(sk, &rt->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:
 	release_sock(sk);
 	return rc;
 }
-- 
1.7.0.4

[PATCH 03/10] l2tp: remove unused stats from l2tp_ip socket

[James Chapman]

The l2tp_ip socket currently maintains packet/byte stats in its
private socket structure. But these counters aren't exposed to
userspace and so serve no purpose. The counters were also
smp-unsafe. So this patch just gets rid of the stats.

While here, change a couple of internal __u32 variables to u32.

Signed-off-by: James Chapman <jchapman@katalix.com>
---
 net/l2tp/l2tp_ip.c |   32 ++++----------------------------
 1 files changed, 4 insertions(+), 28 deletions(-)

diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 5162592..adefe52 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -32,15 +32,8 @@ 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;
+	u32			conn_id;
+	u32			peer_conn_id;
 };
 
 static DEFINE_RWLOCK(l2tp_ip_lock);
@@ -298,7 +291,6 @@ out_in_use:
 static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 {
 	struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
-	struct inet_sock *inet = inet_sk(sk);
 	int rc;
 
 	if (addr_len < sizeof(*lsa))
@@ -374,7 +366,6 @@ static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
 {
 	struct sk_buff *skb;
 	int rc;
-	struct l2tp_ip_sock *lsa = l2tp_ip_sk(sk);
 	struct inet_sock *inet = inet_sk(sk);
 	struct rtable *rt = NULL;
 	struct flowi4 *fl4;
@@ -473,14 +464,8 @@ static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
 	rcu_read_unlock();
 
 error:
-	/* Update stats */
-	if (rc >= 0) {
-		lsa->tx_packets++;
-		lsa->tx_bytes += len;
+	if (rc >= 0)
 		rc = len;
-	} else {
-		lsa->tx_errors++;
-	}
 
 out:
 	release_sock(sk);
@@ -498,7 +483,6 @@ static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
 			   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;
@@ -540,15 +524,7 @@ static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
 done:
 	skb_free_datagram(sk, skb);
 out:
-	if (err) {
-		lsk->rx_errors++;
-		return err;
-	}
-
-	lsk->rx_packets++;
-	lsk->rx_bytes += copied;
-
-	return copied;
+	return err ? err : copied;
 }
 
 static struct proto l2tp_ip_prot = {
-- 
1.7.0.4

[PATCH 04/10] pppox: Replace __attribute__((packed)) in if_pppox.h

[James Chapman]

Checkpatch warns about the use of __attribute__((packed)). So use the
recommended __packed syntax instead.

Signed-off-by: James Chapman <jchapman@katalix.com>
---
 include/linux/if_pppox.h |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/if_pppox.h b/include/linux/if_pppox.h
index 6720d57..09c474c 100644
--- a/include/linux/if_pppox.h
+++ b/include/linux/if_pppox.h
@@ -70,7 +70,7 @@ struct sockaddr_pppox {
 		struct pppoe_addr  pppoe;
 		struct pptp_addr   pptp;
 	} sa_addr;
-} __attribute__((packed));
+} __packed;
 
 /* The use of the above union isn't viable because the size of this
  * struct must stay fixed over time -- applications use sizeof(struct
@@ -81,13 +81,13 @@ struct sockaddr_pppol2tp {
 	__kernel_sa_family_t sa_family; /* address family, AF_PPPOX */
 	unsigned int    sa_protocol;    /* protocol identifier */
 	struct pppol2tp_addr pppol2tp;
-} __attribute__((packed));
+} __packed;
 
 struct sockaddr_pppol2tpin6 {
 	__kernel_sa_family_t sa_family; /* address family, AF_PPPOX */
 	unsigned int    sa_protocol;    /* protocol identifier */
 	struct pppol2tpin6_addr pppol2tp;
-} __attribute__((packed));
+} __packed;
 
 /* The L2TPv3 protocol changes tunnel and session ids from 16 to 32
  * bits. So we need a different sockaddr structure.
@@ -96,13 +96,13 @@ struct sockaddr_pppol2tpv3 {
 	__kernel_sa_family_t sa_family; /* address family, AF_PPPOX */
 	unsigned int    sa_protocol;    /* protocol identifier */
 	struct pppol2tpv3_addr pppol2tp;
-} __attribute__((packed));
+} __packed;
 
 struct sockaddr_pppol2tpv3in6 {
 	__kernel_sa_family_t sa_family; /* address family, AF_PPPOX */
 	unsigned int    sa_protocol;    /* protocol identifier */
 	struct pppol2tpv3in6_addr pppol2tp;
-} __attribute__((packed));
+} __packed;
 
 /*********************************************************************
  *
@@ -152,7 +152,7 @@ struct pppoe_hdr {
 	__be16 sid;
 	__be16 length;
 	struct pppoe_tag tag[0];
-} __attribute__((packed));
+} __packed;
 
 /* Length of entire PPPoE + PPP header */
 #define PPPOE_SES_HLEN	8
-- 
1.7.0.4

[PATCH 05/10] l2tp: pppol2tp_connect() handles ipv6 sockaddr variants

[James Chapman]

Userspace uses connect() to associate a pppol2tp socket with a tunnel
socket. This needs to allow the caller to supply the new IPv6
sockaddr_pppol2tp structures if IPv6 is used.

Signed-off-by: James Chapman <jchapman@katalix.com>
---
 net/l2tp/l2tp_ppp.c |   36 ++++++++++++++++++++++++++++--------
 1 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 27b9dec..9f2c421 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -628,7 +628,6 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 {
 	struct sock *sk = sock->sk;
 	struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
-	struct sockaddr_pppol2tpv3 *sp3 = (struct sockaddr_pppol2tpv3 *) uservaddr;
 	struct pppox_sock *po = pppox_sk(sk);
 	struct l2tp_session *session = NULL;
 	struct l2tp_tunnel *tunnel;
@@ -657,7 +656,13 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	if (sk->sk_user_data)
 		goto end; /* socket is already attached */
 
-	/* Get params from socket address. Handle L2TPv2 and L2TPv3 */
+	/* Get params from socket address. Handle L2TPv2 and L2TPv3.
+	 * This is nasty because there are different sockaddr_pppol2tp
+	 * structs for L2TPv2, L2TPv3, over IPv4 and IPv6. We use
+	 * the sockaddr size to determine which structure the caller
+	 * is using.
+	 */
+	peer_tunnel_id = 0;
 	if (sockaddr_len == sizeof(struct sockaddr_pppol2tp)) {
 		fd = sp->pppol2tp.fd;
 		tunnel_id = sp->pppol2tp.s_tunnel;
@@ -665,12 +670,31 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 		session_id = sp->pppol2tp.s_session;
 		peer_session_id = sp->pppol2tp.d_session;
 	} else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3)) {
+		struct sockaddr_pppol2tpv3 *sp3 =
+			(struct sockaddr_pppol2tpv3 *) sp;
 		ver = 3;
 		fd = sp3->pppol2tp.fd;
 		tunnel_id = sp3->pppol2tp.s_tunnel;
 		peer_tunnel_id = sp3->pppol2tp.d_tunnel;
 		session_id = sp3->pppol2tp.s_session;
 		peer_session_id = sp3->pppol2tp.d_session;
+	} else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpin6)) {
+		struct sockaddr_pppol2tpin6 *sp6 =
+			(struct sockaddr_pppol2tpin6 *) sp;
+		fd = sp6->pppol2tp.fd;
+		tunnel_id = sp6->pppol2tp.s_tunnel;
+		peer_tunnel_id = sp6->pppol2tp.d_tunnel;
+		session_id = sp6->pppol2tp.s_session;
+		peer_session_id = sp6->pppol2tp.d_session;
+	} else if (sockaddr_len == sizeof(struct sockaddr_pppol2tpv3in6)) {
+		struct sockaddr_pppol2tpv3in6 *sp6 =
+			(struct sockaddr_pppol2tpv3in6 *) sp;
+		ver = 3;
+		fd = sp6->pppol2tp.fd;
+		tunnel_id = sp6->pppol2tp.s_tunnel;
+		peer_tunnel_id = sp6->pppol2tp.d_tunnel;
+		session_id = sp6->pppol2tp.s_session;
+		peer_session_id = sp6->pppol2tp.d_session;
 	} else {
 		error = -EINVAL;
 		goto end; /* bad socket address */
@@ -711,12 +735,8 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	if (tunnel->recv_payload_hook == NULL)
 		tunnel->recv_payload_hook = pppol2tp_recv_payload_hook;
 
-	if (tunnel->peer_tunnel_id == 0) {
-		if (ver == 2)
-			tunnel->peer_tunnel_id = sp->pppol2tp.d_tunnel;
-		else
-			tunnel->peer_tunnel_id = sp3->pppol2tp.d_tunnel;
-	}
+	if (tunnel->peer_tunnel_id == 0)
+		tunnel->peer_tunnel_id = peer_tunnel_id;
 
 	/* Create session if it doesn't already exist. We handle the
 	 * case where a session was previously created by the netlink
-- 
1.7.0.4

[PATCH 06/10] l2tp: show IPv6 addresses in l2tp debugfs file

[James Chapman]

From: Chris Elston <celston@katalix.com>

If an L2TP tunnel uses IPv6, make sure the l2tp debugfs file shows the
IPv6 address correctly.

Signed-off-by: Chris Elston <celston@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
---
 net/l2tp/l2tp_debugfs.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c
index 7613013..c0d57ba 100644
--- a/net/l2tp/l2tp_debugfs.c
+++ b/net/l2tp/l2tp_debugfs.c
@@ -122,6 +122,14 @@ static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
 	seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
 	if (tunnel->sock) {
 		struct inet_sock *inet = inet_sk(tunnel->sock);
+
+#if IS_ENABLED(CONFIG_IPV6)
+		if (tunnel->sock->sk_family == AF_INET6) {
+			struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
+			seq_printf(m, " from %pI6c to %pI6c\n",
+				&np->saddr, &np->daddr);
+		} else
+#endif
 		seq_printf(m, " from %pI4 to %pI4\n",
 			   &inet->inet_saddr, &inet->inet_daddr);
 		if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
-- 
1.7.0.4

[PATCH 07/10] l2tp: netlink api for l2tpv3 ipv6 unmanaged tunnels

[James Chapman]

From: Chris Elston <celston@katalix.com>

This patch adds support for unmanaged L2TPv3 tunnels over IPv6 using
the netlink API. We already support unmanaged L2TPv3 tunnels over
IPv4. A patch to iproute2 to make use of this feature will be
submitted separately.

Signed-off-by: Chris Elston <celston@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
---
 include/linux/l2tp.h    |    2 +
 net/l2tp/l2tp_core.c    |   78 ++++++++++++++++++++++++++++++++++++----------
 net/l2tp/l2tp_core.h    |    4 ++
 net/l2tp/l2tp_netlink.c |   48 ++++++++++++++++++++++++++--
 4 files changed, 111 insertions(+), 21 deletions(-)

diff --git a/include/linux/l2tp.h b/include/linux/l2tp.h
index e77d7f9..16b8347 100644
--- a/include/linux/l2tp.h
+++ b/include/linux/l2tp.h
@@ -108,6 +108,8 @@ enum {
 	L2TP_ATTR_MTU,			/* u16 */
 	L2TP_ATTR_MRU,			/* u16 */
 	L2TP_ATTR_STATS,		/* nested */
+	L2TP_ATTR_IP6_SADDR,		/* struct in6_addr */
+	L2TP_ATTR_IP6_DADDR,		/* struct in6_addr */
 	__L2TP_ATTR_MAX,
 };
 
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 5e27c05..5a7d908 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1365,31 +1365,68 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
 {
 	int err = -EINVAL;
 	struct sockaddr_in udp_addr;
+#if IS_ENABLED(CONFIG_IPV6)
+	struct sockaddr_in6 udp6_addr;
+#endif
 	struct sockaddr_l2tpip ip_addr;
 	struct socket *sock = NULL;
 
 	switch (cfg->encap) {
 	case L2TP_ENCAPTYPE_UDP:
-		err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
-		if (err < 0)
-			goto out;
+#if IS_ENABLED(CONFIG_IPV6)
+		if (cfg->local_ip6 && cfg->peer_ip6) {
+			err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp);
+			if (err < 0)
+				goto out;
 
-		sock = *sockp;
+			sock = *sockp;
 
-		memset(&udp_addr, 0, sizeof(udp_addr));
-		udp_addr.sin_family = AF_INET;
-		udp_addr.sin_addr = cfg->local_ip;
-		udp_addr.sin_port = htons(cfg->local_udp_port);
-		err = kernel_bind(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr));
-		if (err < 0)
-			goto out;
+			memset(&udp6_addr, 0, sizeof(udp6_addr));
+			udp6_addr.sin6_family = AF_INET6;
+			memcpy(&udp6_addr.sin6_addr, cfg->local_ip6,
+			       sizeof(udp6_addr.sin6_addr));
+			udp6_addr.sin6_port = htons(cfg->local_udp_port);
+			err = kernel_bind(sock, (struct sockaddr *) &udp6_addr,
+					  sizeof(udp6_addr));
+			if (err < 0)
+				goto out;
 
-		udp_addr.sin_family = AF_INET;
-		udp_addr.sin_addr = cfg->peer_ip;
-		udp_addr.sin_port = htons(cfg->peer_udp_port);
-		err = kernel_connect(sock, (struct sockaddr *) &udp_addr, sizeof(udp_addr), 0);
-		if (err < 0)
-			goto out;
+			udp6_addr.sin6_family = AF_INET6;
+			memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6,
+			       sizeof(udp6_addr.sin6_addr));
+			udp6_addr.sin6_port = htons(cfg->peer_udp_port);
+			err = kernel_connect(sock,
+					     (struct sockaddr *) &udp6_addr,
+					     sizeof(udp6_addr), 0);
+			if (err < 0)
+				goto out;
+		} else
+#endif
+		{
+			err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp);
+			if (err < 0)
+				goto out;
+
+			sock = *sockp;
+
+			memset(&udp_addr, 0, sizeof(udp_addr));
+			udp_addr.sin_family = AF_INET;
+			udp_addr.sin_addr = cfg->local_ip;
+			udp_addr.sin_port = htons(cfg->local_udp_port);
+			err = kernel_bind(sock, (struct sockaddr *) &udp_addr,
+					  sizeof(udp_addr));
+			if (err < 0)
+				goto out;
+
+			udp_addr.sin_family = AF_INET;
+			udp_addr.sin_addr = cfg->peer_ip;
+			udp_addr.sin_port = htons(cfg->peer_udp_port);
+			err = kernel_connect(sock,
+					     (struct sockaddr *) &udp_addr,
+					     sizeof(udp_addr), 0);
+			if (err < 0)
+				goto out;
+		}
 
 		if (!cfg->use_udp_checksums)
 			sock->sk->sk_no_check = UDP_CSUM_NOXMIT;
@@ -1397,6 +1434,13 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
 		break;
 
 	case L2TP_ENCAPTYPE_IP:
+#if IS_ENABLED(CONFIG_IPV6)
+		if (cfg->local_ip6 && cfg->peer_ip6) {
+			/* IP encap over IPv6 not yet supported */
+			err = -EPROTONOSUPPORT;
+			goto out;
+		}
+#endif
 		err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
 		if (err < 0)
 			goto out;
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index a8c943b..0bf60fc 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -151,6 +151,10 @@ struct l2tp_tunnel_cfg {
 	/* Used only for kernel-created sockets */
 	struct in_addr		local_ip;
 	struct in_addr		peer_ip;
+#if IS_ENABLED(CONFIG_IPV6)
+	struct in6_addr		*local_ip6;
+	struct in6_addr		*peer_ip6;
+#endif
 	u16			local_udp_port;
 	u16			peer_udp_port;
 	unsigned int		use_udp_checksums:1;
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 1dbb977..24edad0 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -133,10 +133,25 @@ static int l2tp_nl_cmd_tunnel_create(struct sk_buff *skb, struct genl_info *info
 	if (info->attrs[L2TP_ATTR_FD]) {
 		fd = nla_get_u32(info->attrs[L2TP_ATTR_FD]);
 	} else {
-		if (info->attrs[L2TP_ATTR_IP_SADDR])
-			cfg.local_ip.s_addr = nla_get_be32(info->attrs[L2TP_ATTR_IP_SADDR]);
-		if (info->attrs[L2TP_ATTR_IP_DADDR])
-			cfg.peer_ip.s_addr = nla_get_be32(info->attrs[L2TP_ATTR_IP_DADDR]);
+#if IS_ENABLED(CONFIG_IPV6)
+		if (info->attrs[L2TP_ATTR_IP6_SADDR] &&
+		    info->attrs[L2TP_ATTR_IP6_DADDR]) {
+			cfg.local_ip6 = nla_data(
+				info->attrs[L2TP_ATTR_IP6_SADDR]);
+			cfg.peer_ip6 = nla_data(
+				info->attrs[L2TP_ATTR_IP6_DADDR]);
+		} else
+#endif
+		if (info->attrs[L2TP_ATTR_IP_SADDR] &&
+		    info->attrs[L2TP_ATTR_IP_DADDR]) {
+			cfg.local_ip.s_addr = nla_get_be32(
+				info->attrs[L2TP_ATTR_IP_SADDR]);
+			cfg.peer_ip.s_addr = nla_get_be32(
+				info->attrs[L2TP_ATTR_IP_DADDR]);
+		} else {
+			ret = -EINVAL;
+			goto out;
+		}
 		if (info->attrs[L2TP_ATTR_UDP_SPORT])
 			cfg.local_udp_port = nla_get_u16(info->attrs[L2TP_ATTR_UDP_SPORT]);
 		if (info->attrs[L2TP_ATTR_UDP_DPORT])
@@ -225,6 +240,9 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
 	struct nlattr *nest;
 	struct sock *sk = NULL;
 	struct inet_sock *inet;
+#if IS_ENABLED(CONFIG_IPV6)
+	struct ipv6_pinfo *np = NULL;
+#endif
 	struct l2tp_stats stats;
 	unsigned int start;
 
@@ -273,6 +291,11 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
 	if (!sk)
 		goto out;
 
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == AF_INET6)
+		np = inet6_sk(sk);
+#endif
+
 	inet = inet_sk(sk);
 
 	switch (tunnel->encap) {
@@ -284,6 +307,15 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
 			goto nla_put_failure;
 		/* NOBREAK */
 	case L2TP_ENCAPTYPE_IP:
+#if IS_ENABLED(CONFIG_IPV6)
+		if (np) {
+			if (nla_put(skb, L2TP_ATTR_IP6_SADDR, sizeof(np->saddr),
+				    &np->saddr) ||
+			    nla_put(skb, L2TP_ATTR_IP6_DADDR, sizeof(np->daddr),
+				    &np->daddr))
+				goto nla_put_failure;
+		} else
+#endif
 		if (nla_put_be32(skb, L2TP_ATTR_IP_SADDR, inet->inet_saddr) ||
 		    nla_put_be32(skb, L2TP_ATTR_IP_DADDR, inet->inet_daddr))
 			goto nla_put_failure;
@@ -752,6 +784,14 @@ static struct nla_policy l2tp_nl_policy[L2TP_ATTR_MAX + 1] = {
 	[L2TP_ATTR_MTU]			= { .type = NLA_U16, },
 	[L2TP_ATTR_MRU]			= { .type = NLA_U16, },
 	[L2TP_ATTR_STATS]		= { .type = NLA_NESTED, },
+	[L2TP_ATTR_IP6_SADDR] = {
+		.type = NLA_BINARY,
+		.len = sizeof(struct in6_addr),
+	},
+	[L2TP_ATTR_IP6_DADDR] = {
+		.type = NLA_BINARY,
+		.len = sizeof(struct in6_addr),
+	},
 	[L2TP_ATTR_IFNAME] = {
 		.type = NLA_NUL_STRING,
 		.len = IFNAMSIZ - 1,
-- 
1.7.0.4

[PATCH 08/10] ipv6: Export ipv6 functions for use by other protocols

[James Chapman]

From: Chris Elston <celston@katalix.com>

For implementing other protocols on top of IPv6, such as L2TPv3's IP
encapsulation over ipv6, we'd like to call some IPv6 functions which
are not currently exported. This patch exports them.

Signed-off-by: Chris Elston <celston@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
---
 net/ipv6/datagram.c      |    4 ++++
 net/ipv6/exthdrs.c       |    1 +
 net/ipv6/ip6_flowlabel.c |    1 +
 net/ipv6/ip6_output.c    |    3 +++
 4 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 7fba35a..b8b61ac 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -22,6 +22,7 @@
 #include <linux/ipv6.h>
 #include <linux/route.h>
 #include <linux/slab.h>
+#include <linux/export.h>
 
 #include <net/ipv6.h>
 #include <net/ndisc.h>
@@ -202,6 +203,7 @@ out:
 	fl6_sock_release(flowlabel);
 	return err;
 }
+EXPORT_SYMBOL_GPL(ip6_datagram_connect);
 
 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 		     __be16 port, u32 info, u8 *payload)
@@ -414,6 +416,7 @@ out_free_skb:
 out:
 	return err;
 }
+EXPORT_SYMBOL_GPL(ipv6_recv_error);
 
 /*
  *	Handle IPV6_RECVPATHMTU
@@ -868,3 +871,4 @@ int datagram_send_ctl(struct net *net, struct sock *sk,
 exit_f:
 	return err;
 }
+EXPORT_SYMBOL_GPL(datagram_send_ctl);
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index aa0a51e..a93bd23 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -883,6 +883,7 @@ struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 
 	return opt;
 }
+EXPORT_SYMBOL_GPL(ipv6_fixup_options);
 
 /**
  * fl6_update_dst - update flowi destination address with info given
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index 1dd6329..cb43df6 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -294,6 +294,7 @@ struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space,
 	opt_space->opt_flen = fopt->opt_flen;
 	return opt_space;
 }
+EXPORT_SYMBOL_GPL(fl6_merge_options);
 
 static unsigned long check_linger(unsigned long ttl)
 {
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index b7ca461..2a16aa9 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1535,6 +1535,7 @@ error:
 	IP6_INC_STATS(sock_net(sk), rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
 	return err;
 }
+EXPORT_SYMBOL_GPL(ip6_append_data);
 
 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
 {
@@ -1638,6 +1639,7 @@ error:
 	IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
 	goto out;
 }
+EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
 
 void ip6_flush_pending_frames(struct sock *sk)
 {
@@ -1652,3 +1654,4 @@ void ip6_flush_pending_frames(struct sock *sk)
 
 	ip6_cork_release(inet_sk(sk), inet6_sk(sk));
 }
+EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
-- 
1.7.0.4

[PATCH 09/10] l2tp: introduce L2TPv3 IP encapsulation support for IPv6

[James Chapman]

From: Chris Elston <celston@katalix.com>

L2TPv3 defines an IP encapsulation packet format where data is carried
directly over IP (no UDP). The kernel already has support for L2TP IP
encapsulation over IPv4 (l2tp_ip). This patch introduces support for
L2TP IP encapsulation over IPv6.

The implementation is derived from ipv6/raw and ipv4/l2tp_ip.

Signed-off-by: Chris Elston <celston@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
---
 include/linux/l2tp.h |   17 +
 net/l2tp/Makefile    |    3 +
 net/l2tp/l2tp_ip6.c  |  792 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 812 insertions(+), 0 deletions(-)
 create mode 100644 net/l2tp/l2tp_ip6.c

diff --git a/include/linux/l2tp.h b/include/linux/l2tp.h
index 16b8347..7eab668 100644
--- a/include/linux/l2tp.h
+++ b/include/linux/l2tp.h
@@ -11,6 +11,7 @@
 #include <linux/socket.h>
 #ifdef __KERNEL__
 #include <linux/in.h>
+#include <linux/in6.h>
 #else
 #include <netinet/in.h>
 #endif
@@ -39,6 +40,22 @@ struct sockaddr_l2tpip {
 			      sizeof(__u32)];
 };
 
+/**
+ * struct sockaddr_l2tpip6 - the sockaddr structure for L2TP-over-IPv6 sockets
+ * @l2tp_family:  address family number AF_L2TPIP.
+ * @l2tp_addr:    protocol specific address information
+ * @l2tp_conn_id: connection id of tunnel
+ */
+struct sockaddr_l2tpip6 {
+	/* The first fields must match struct sockaddr_in6 */
+	__kernel_sa_family_t l2tp_family; /* AF_INET6 */
+	__be16		l2tp_unused;	/* INET port number (unused) */
+	__be32		l2tp_flowinfo;	/* IPv6 flow information */
+	struct in6_addr	l2tp_addr;	/* IPv6 address */
+	__u32		l2tp_scope_id;	/* scope id (new in RFC2553) */
+	__u32		l2tp_conn_id;	/* Connection ID of tunnel */
+};
+
 /*****************************************************************************
  *  NETLINK_GENERIC netlink family.
  *****************************************************************************/
diff --git a/net/l2tp/Makefile b/net/l2tp/Makefile
index 110e7bc..2870f41 100644
--- a/net/l2tp/Makefile
+++ b/net/l2tp/Makefile
@@ -10,3 +10,6 @@ obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP)) += l2tp_ip.o
 obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_V3)) += l2tp_netlink.o
 obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_ETH)) += l2tp_eth.o
 obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_DEBUGFS)) += l2tp_debugfs.o
+ifneq ($(CONFIG_IPV6),)
+obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP)) += l2tp_ip6.o
+endif
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
new file mode 100644
index 0000000..88f0abe
--- /dev/null
+++ b/net/l2tp/l2tp_ip6.c
@@ -0,0 +1,792 @@
+/*
+ * L2TPv3 IP encapsulation support for IPv6
+ *
+ * Copyright (c) 2012 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 <linux/in6.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 <net/transp_v6.h>
+#include <net/addrconf.h>
+#include <net/ip6_route.h>
+
+#include "l2tp_core.h"
+
+struct l2tp_ip6_sock {
+	/* inet_sock has to be the first member of l2tp_ip6_sock */
+	struct inet_sock	inet;
+
+	u32			conn_id;
+	u32			peer_conn_id;
+
+	/* ipv6_pinfo has to be the last member of l2tp_ip6_sock, see
+	   inet6_sk_generic */
+	struct ipv6_pinfo	inet6;
+};
+
+static DEFINE_RWLOCK(l2tp_ip6_lock);
+static struct hlist_head l2tp_ip6_table;
+static struct hlist_head l2tp_ip6_bind_table;
+
+static inline struct l2tp_ip6_sock *l2tp_ip6_sk(const struct sock *sk)
+{
+	return (struct l2tp_ip6_sock *)sk;
+}
+
+static struct sock *__l2tp_ip6_bind_lookup(struct net *net,
+					   struct in6_addr *laddr,
+					   int dif, u32 tunnel_id)
+{
+	struct hlist_node *node;
+	struct sock *sk;
+
+	sk_for_each_bound(sk, node, &l2tp_ip6_bind_table) {
+		struct in6_addr *addr = inet6_rcv_saddr(sk);
+		struct l2tp_ip6_sock *l2tp = l2tp_ip6_sk(sk);
+
+		if (l2tp == NULL)
+			continue;
+
+		if ((l2tp->conn_id == tunnel_id) &&
+		    net_eq(sock_net(sk), net) &&
+		    !(addr && ipv6_addr_equal(addr, laddr)) &&
+		    !(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
+			goto found;
+	}
+
+	sk = NULL;
+found:
+	return sk;
+}
+
+static inline struct sock *l2tp_ip6_bind_lookup(struct net *net,
+						struct in6_addr *laddr,
+						int dif, u32 tunnel_id)
+{
+	struct sock *sk = __l2tp_ip6_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_ip6_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 ipv6hdr *iph = ipv6_hdr(skb);
+
+		read_lock_bh(&l2tp_ip6_lock);
+		sk = __l2tp_ip6_bind_lookup(&init_net, &iph->daddr,
+					    0, tunnel_id);
+		read_unlock_bh(&l2tp_ip6_lock);
+	}
+
+	if (sk == NULL)
+		goto discard;
+
+	sock_hold(sk);
+
+	if (!xfrm6_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_ip6_open(struct sock *sk)
+{
+	/* Prevent autobind. We don't have ports. */
+	inet_sk(sk)->inet_num = IPPROTO_L2TP;
+
+	write_lock_bh(&l2tp_ip6_lock);
+	sk_add_node(sk, &l2tp_ip6_table);
+	write_unlock_bh(&l2tp_ip6_lock);
+
+	return 0;
+}
+
+static void l2tp_ip6_close(struct sock *sk, long timeout)
+{
+	write_lock_bh(&l2tp_ip6_lock);
+	hlist_del_init(&sk->sk_bind_node);
+	sk_del_node_init(sk);
+	write_unlock_bh(&l2tp_ip6_lock);
+
+	sk_common_release(sk);
+}
+
+static void l2tp_ip6_destroy_sock(struct sock *sk)
+{
+	lock_sock(sk);
+	ip6_flush_pending_frames(sk);
+	release_sock(sk);
+
+	inet6_destroy_sock(sk);
+}
+
+static int l2tp_ip6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct sockaddr_l2tpip6 *addr = (struct sockaddr_l2tpip6 *) uaddr;
+	__be32 v4addr = 0;
+	int addr_type;
+	int err;
+
+	if (addr_len < sizeof(*addr))
+		return -EINVAL;
+
+	addr_type = ipv6_addr_type(&addr->l2tp_addr);
+
+	/* l2tp_ip6 sockets are IPv6 only */
+	if (addr_type == IPV6_ADDR_MAPPED)
+		return -EADDRNOTAVAIL;
+
+	/* L2TP is point-point, not multicast */
+	if (addr_type & IPV6_ADDR_MULTICAST)
+		return -EADDRNOTAVAIL;
+
+	err = -EADDRINUSE;
+	read_lock_bh(&l2tp_ip6_lock);
+	if (__l2tp_ip6_bind_lookup(&init_net, &addr->l2tp_addr,
+				   sk->sk_bound_dev_if, addr->l2tp_conn_id))
+		goto out_in_use;
+	read_unlock_bh(&l2tp_ip6_lock);
+
+	lock_sock(sk);
+
+	err = -EINVAL;
+	if (sk->sk_state != TCP_CLOSE)
+		goto out_unlock;
+
+	/* Check if the address belongs to the host. */
+	rcu_read_lock();
+	if (addr_type != IPV6_ADDR_ANY) {
+		struct net_device *dev = NULL;
+
+		if (addr_type & IPV6_ADDR_LINKLOCAL) {
+			if (addr_len >= sizeof(struct sockaddr_in6) &&
+			    addr->l2tp_scope_id) {
+				/* Override any existing binding, if another
+				 * one is supplied by user.
+				 */
+				sk->sk_bound_dev_if = addr->l2tp_scope_id;
+			}
+
+			/* Binding to link-local address requires an
+			   interface */
+			if (!sk->sk_bound_dev_if)
+				goto out_unlock_rcu;
+
+			err = -ENODEV;
+			dev = dev_get_by_index_rcu(sock_net(sk),
+						   sk->sk_bound_dev_if);
+			if (!dev)
+				goto out_unlock_rcu;
+		}
+
+		/* ipv4 addr of the socket is invalid.  Only the
+		 * unspecified and mapped address have a v4 equivalent.
+		 */
+		v4addr = LOOPBACK4_IPV6;
+		err = -EADDRNOTAVAIL;
+		if (!ipv6_chk_addr(sock_net(sk), &addr->l2tp_addr, dev, 0))
+			goto out_unlock_rcu;
+	}
+	rcu_read_unlock();
+
+	inet->inet_rcv_saddr = inet->inet_saddr = v4addr;
+	np->rcv_saddr = addr->l2tp_addr;
+	np->saddr = addr->l2tp_addr;
+
+	l2tp_ip6_sk(sk)->conn_id = addr->l2tp_conn_id;
+
+	write_lock_bh(&l2tp_ip6_lock);
+	sk_add_bind_node(sk, &l2tp_ip6_bind_table);
+	sk_del_node_init(sk);
+	write_unlock_bh(&l2tp_ip6_lock);
+
+	release_sock(sk);
+	return 0;
+
+out_unlock_rcu:
+	rcu_read_unlock();
+out_unlock:
+	release_sock(sk);
+	return err;
+
+out_in_use:
+	read_unlock_bh(&l2tp_ip6_lock);
+	return err;
+}
+
+static int l2tp_ip6_connect(struct sock *sk, struct sockaddr *uaddr,
+			    int addr_len)
+{
+	struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *) uaddr;
+	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;
+	struct in6_addr	*daddr;
+	int	addr_type;
+	int rc;
+
+	if (addr_len < sizeof(*lsa))
+		return -EINVAL;
+
+	addr_type = ipv6_addr_type(&usin->sin6_addr);
+	if (addr_type & IPV6_ADDR_MULTICAST)
+		return -EINVAL;
+
+	if (addr_type & IPV6_ADDR_MAPPED) {
+		daddr = &usin->sin6_addr;
+		if (ipv4_is_multicast(daddr->s6_addr32[3]))
+			return -EINVAL;
+	}
+
+	rc = ip6_datagram_connect(sk, uaddr, addr_len);
+
+	lock_sock(sk);
+
+	l2tp_ip6_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
+
+	write_lock_bh(&l2tp_ip6_lock);
+	hlist_del_init(&sk->sk_bind_node);
+	sk_add_bind_node(sk, &l2tp_ip6_bind_table);
+	write_unlock_bh(&l2tp_ip6_lock);
+
+	release_sock(sk);
+
+	return rc;
+}
+
+static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr,
+			    int *uaddr_len, int peer)
+{
+	struct sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)uaddr;
+	struct sock *sk = sock->sk;
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct l2tp_ip6_sock *lsk = l2tp_ip6_sk(sk);
+
+	lsa->l2tp_family = AF_INET6;
+	lsa->l2tp_flowinfo = 0;
+	lsa->l2tp_scope_id = 0;
+	if (peer) {
+		if (!lsk->peer_conn_id)
+			return -ENOTCONN;
+		lsa->l2tp_conn_id = lsk->peer_conn_id;
+		lsa->l2tp_addr = np->daddr;
+		if (np->sndflow)
+			lsa->l2tp_flowinfo = np->flow_label;
+	} else {
+		if (ipv6_addr_any(&np->rcv_saddr))
+			lsa->l2tp_addr = np->saddr;
+		else
+			lsa->l2tp_addr = np->rcv_saddr;
+
+		lsa->l2tp_conn_id = lsk->conn_id;
+	}
+	if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
+		lsa->l2tp_scope_id = sk->sk_bound_dev_if;
+	*uaddr_len = sizeof(*lsa);
+	return 0;
+}
+
+static int l2tp_ip6_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(&init_net, IPSTATS_MIB_INDISCARDS);
+	kfree_skb(skb);
+	return -1;
+}
+
+static int l2tp_ip6_push_pending_frames(struct sock *sk)
+{
+	struct sk_buff *skb;
+	__be32 *transhdr = NULL;
+	int err = 0;
+
+	skb = skb_peek(&sk->sk_write_queue);
+	if (skb == NULL)
+		goto out;
+
+	transhdr = (__be32 *)skb_transport_header(skb);
+	*transhdr = 0;
+
+	err = ip6_push_pending_frames(sk);
+
+out:
+	return err;
+}
+
+/* Userspace will call sendmsg() on the tunnel socket to send L2TP
+ * control frames.
+ */
+static int l2tp_ip6_sendmsg(struct kiocb *iocb, struct sock *sk,
+			    struct msghdr *msg, size_t len)
+{
+	struct ipv6_txoptions opt_space;
+	struct sockaddr_l2tpip6 *lsa =
+		(struct sockaddr_l2tpip6 *) msg->msg_name;
+	struct in6_addr *daddr, *final_p, final;
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct ipv6_txoptions *opt = NULL;
+	struct ip6_flowlabel *flowlabel = NULL;
+	struct dst_entry *dst = NULL;
+	struct flowi6 fl6;
+	int addr_len = msg->msg_namelen;
+	int hlimit = -1;
+	int tclass = -1;
+	int dontfrag = -1;
+	int transhdrlen = 4; /* zero session-id */
+	int ulen = len + transhdrlen;
+	int err;
+
+	/* Rough check on arithmetic overflow,
+	   better check is made in ip6_append_data().
+	 */
+	if (len > INT_MAX)
+		return -EMSGSIZE;
+
+	/* Mirror BSD error message compatibility */
+	if (msg->msg_flags & MSG_OOB)
+		return -EOPNOTSUPP;
+
+	/*
+	 *	Get and verify the address.
+	 */
+	memset(&fl6, 0, sizeof(fl6));
+
+	fl6.flowi6_mark = sk->sk_mark;
+
+	if (lsa) {
+		if (addr_len < SIN6_LEN_RFC2133)
+			return -EINVAL;
+
+		if (lsa->l2tp_family && lsa->l2tp_family != AF_INET6)
+			return -EAFNOSUPPORT;
+
+		daddr = &lsa->l2tp_addr;
+		if (np->sndflow) {
+			fl6.flowlabel = lsa->l2tp_flowinfo & IPV6_FLOWINFO_MASK;
+			if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
+				flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
+				if (flowlabel == NULL)
+					return -EINVAL;
+				daddr = &flowlabel->dst;
+			}
+		}
+
+		/*
+		 * Otherwise it will be difficult to maintain
+		 * sk->sk_dst_cache.
+		 */
+		if (sk->sk_state == TCP_ESTABLISHED &&
+		    ipv6_addr_equal(daddr, &np->daddr))
+			daddr = &np->daddr;
+
+		if (addr_len >= sizeof(struct sockaddr_in6) &&
+		    lsa->l2tp_scope_id &&
+		    ipv6_addr_type(daddr) & IPV6_ADDR_LINKLOCAL)
+			fl6.flowi6_oif = lsa->l2tp_scope_id;
+	} else {
+		if (sk->sk_state != TCP_ESTABLISHED)
+			return -EDESTADDRREQ;
+
+		daddr = &np->daddr;
+		fl6.flowlabel = np->flow_label;
+	}
+
+	if (fl6.flowi6_oif == 0)
+		fl6.flowi6_oif = sk->sk_bound_dev_if;
+
+	if (msg->msg_controllen) {
+		opt = &opt_space;
+		memset(opt, 0, sizeof(struct ipv6_txoptions));
+		opt->tot_len = sizeof(struct ipv6_txoptions);
+
+		err = datagram_send_ctl(sock_net(sk), sk, msg, &fl6, opt,
+					&hlimit, &tclass, &dontfrag);
+		if (err < 0) {
+			fl6_sock_release(flowlabel);
+			return err;
+		}
+		if ((fl6.flowlabel & IPV6_FLOWLABEL_MASK) && !flowlabel) {
+			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
+			if (flowlabel == NULL)
+				return -EINVAL;
+		}
+		if (!(opt->opt_nflen|opt->opt_flen))
+			opt = NULL;
+	}
+
+	if (opt == NULL)
+		opt = np->opt;
+	if (flowlabel)
+		opt = fl6_merge_options(&opt_space, flowlabel, opt);
+	opt = ipv6_fixup_options(&opt_space, opt);
+
+	fl6.flowi6_proto = sk->sk_protocol;
+	if (!ipv6_addr_any(daddr))
+		fl6.daddr = *daddr;
+	else
+		fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
+	if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr))
+		fl6.saddr = np->saddr;
+
+	final_p = fl6_update_dst(&fl6, opt, &final);
+
+	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
+		fl6.flowi6_oif = np->mcast_oif;
+	else if (!fl6.flowi6_oif)
+		fl6.flowi6_oif = np->ucast_oif;
+
+	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
+
+	dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
+	if (IS_ERR(dst)) {
+		err = PTR_ERR(dst);
+		goto out;
+	}
+
+	if (hlimit < 0) {
+		if (ipv6_addr_is_multicast(&fl6.daddr))
+			hlimit = np->mcast_hops;
+		else
+			hlimit = np->hop_limit;
+		if (hlimit < 0)
+			hlimit = ip6_dst_hoplimit(dst);
+	}
+
+	if (tclass < 0)
+		tclass = np->tclass;
+
+	if (dontfrag < 0)
+		dontfrag = np->dontfrag;
+
+	if (msg->msg_flags & MSG_CONFIRM)
+		goto do_confirm;
+
+back_from_confirm:
+	lock_sock(sk);
+	err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
+			      ulen, transhdrlen, hlimit, tclass, opt,
+			      &fl6, (struct rt6_info *)dst,
+			      msg->msg_flags, dontfrag);
+	if (err)
+		ip6_flush_pending_frames(sk);
+	else if (!(msg->msg_flags & MSG_MORE))
+		err = l2tp_ip6_push_pending_frames(sk);
+	release_sock(sk);
+done:
+	dst_release(dst);
+out:
+	fl6_sock_release(flowlabel);
+
+	return err < 0 ? err : len;
+
+do_confirm:
+	dst_confirm(dst);
+	if (!(msg->msg_flags & MSG_PROBE) || len)
+		goto back_from_confirm;
+	err = 0;
+	goto done;
+}
+
+static int l2tp_ip6_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 sockaddr_l2tpip6 *lsa = (struct sockaddr_l2tpip6 *)msg->msg_name;
+	size_t copied = 0;
+	int err = -EOPNOTSUPP;
+	struct sk_buff *skb;
+
+	if (flags & MSG_OOB)
+		goto out;
+
+	if (addr_len)
+		*addr_len = sizeof(*lsa);
+
+	if (flags & MSG_ERRQUEUE)
+		return ipv6_recv_error(sk, msg, len);
+
+	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 (lsa) {
+		lsa->l2tp_family = AF_INET6;
+		lsa->l2tp_unused = 0;
+		lsa->l2tp_addr = ipv6_hdr(skb)->saddr;
+		lsa->l2tp_flowinfo = 0;
+		lsa->l2tp_scope_id = 0;
+		if (ipv6_addr_type(&lsa->l2tp_addr) & IPV6_ADDR_LINKLOCAL)
+			lsa->l2tp_scope_id = IP6CB(skb)->iif;
+	}
+
+	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_ip6_prot = {
+	.name		   = "L2TP/IPv6",
+	.owner		   = THIS_MODULE,
+	.init		   = l2tp_ip6_open,
+	.close		   = l2tp_ip6_close,
+	.bind		   = l2tp_ip6_bind,
+	.connect	   = l2tp_ip6_connect,
+	.disconnect	   = udp_disconnect,
+	.ioctl		   = udp_ioctl,
+	.destroy	   = l2tp_ip6_destroy_sock,
+	.setsockopt	   = ipv6_setsockopt,
+	.getsockopt	   = ipv6_getsockopt,
+	.sendmsg	   = l2tp_ip6_sendmsg,
+	.recvmsg	   = l2tp_ip6_recvmsg,
+	.backlog_rcv	   = l2tp_ip6_backlog_recv,
+	.hash		   = inet_hash,
+	.unhash		   = inet_unhash,
+	.obj_size	   = sizeof(struct l2tp_ip6_sock),
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt = compat_ipv6_setsockopt,
+	.compat_getsockopt = compat_ipv6_getsockopt,
+#endif
+};
+
+static const struct proto_ops l2tp_ip6_ops = {
+	.family		   = PF_INET6,
+	.owner		   = THIS_MODULE,
+	.release	   = inet6_release,
+	.bind		   = inet6_bind,
+	.connect	   = inet_dgram_connect,
+	.socketpair	   = sock_no_socketpair,
+	.accept		   = sock_no_accept,
+	.getname	   = l2tp_ip6_getname,
+	.poll		   = datagram_poll,
+	.ioctl		   = inet6_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_ip6_protosw = {
+	.type		= SOCK_DGRAM,
+	.protocol	= IPPROTO_L2TP,
+	.prot		= &l2tp_ip6_prot,
+	.ops		= &l2tp_ip6_ops,
+	.no_check	= 0,
+};
+
+static struct inet6_protocol l2tp_ip6_protocol __read_mostly = {
+	.handler	= l2tp_ip6_recv,
+};
+
+static int __init l2tp_ip6_init(void)
+{
+	int err;
+
+	printk(KERN_INFO "L2TP IP encapsulation support for IPv6 (L2TPv3)\n");
+
+	err = proto_register(&l2tp_ip6_prot, 1);
+	if (err != 0)
+		goto out;
+
+	err = inet6_add_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
+	if (err)
+		goto out1;
+
+	inet6_register_protosw(&l2tp_ip6_protosw);
+	return 0;
+
+out1:
+	proto_unregister(&l2tp_ip6_prot);
+out:
+	return err;
+}
+
+static void __exit l2tp_ip6_exit(void)
+{
+	inet6_unregister_protosw(&l2tp_ip6_protosw);
+	inet6_del_protocol(&l2tp_ip6_protocol, IPPROTO_L2TP);
+	proto_unregister(&l2tp_ip6_prot);
+}
+
+module_init(l2tp_ip6_init);
+module_exit(l2tp_ip6_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Chris Elston <celston@katalix.com>");
+MODULE_DESCRIPTION("L2TP IP encapsulation for IPv6");
+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_INET6, 2, IPPROTO_L2TP);
-- 
1.7.0.4

[PATCH 10/10] l2tp: let iproute2 create L2TPv3 IP tunnels using IPv6

[James Chapman]

The netlink API lets users create unmanaged L2TPv3 tunnels using
iproute2. Until now, a request to create an unmanaged L2TPv3 IP
encapsulation tunnel over IPv6 would be rejected with
EPROTONOSUPPORT. Now that l2tp_ip6 implements sockets for L2TP IP
encapsulation over IPv6, we can add support for that tunnel type.

Signed-off-by: James Chapman <jchapman@katalix.com>
---
 net/l2tp/l2tp_core.c |   72 ++++++++++++++++++++++++++++++++++---------------
 1 files changed, 50 insertions(+), 22 deletions(-)

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 5a7d908..7415620 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1367,6 +1367,7 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
 	struct sockaddr_in udp_addr;
 #if IS_ENABLED(CONFIG_IPV6)
 	struct sockaddr_in6 udp6_addr;
+	struct sockaddr_l2tpip6 ip6_addr;
 #endif
 	struct sockaddr_l2tpip ip_addr;
 	struct socket *sock = NULL;
@@ -1436,32 +1437,59 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
 	case L2TP_ENCAPTYPE_IP:
 #if IS_ENABLED(CONFIG_IPV6)
 		if (cfg->local_ip6 && cfg->peer_ip6) {
-			/* IP encap over IPv6 not yet supported */
-			err = -EPROTONOSUPPORT;
-			goto out;
-		}
-#endif
-		err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
-		if (err < 0)
-			goto out;
+			err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP,
+					  sockp);
+			if (err < 0)
+				goto out;
 
-		sock = *sockp;
+			sock = *sockp;
 
-		memset(&ip_addr, 0, sizeof(ip_addr));
-		ip_addr.l2tp_family = AF_INET;
-		ip_addr.l2tp_addr = cfg->local_ip;
-		ip_addr.l2tp_conn_id = tunnel_id;
-		err = kernel_bind(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr));
-		if (err < 0)
-			goto out;
+			memset(&ip6_addr, 0, sizeof(ip6_addr));
+			ip6_addr.l2tp_family = AF_INET6;
+			memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6,
+			       sizeof(ip6_addr.l2tp_addr));
+			ip6_addr.l2tp_conn_id = tunnel_id;
+			err = kernel_bind(sock, (struct sockaddr *) &ip6_addr,
+					  sizeof(ip6_addr));
+			if (err < 0)
+				goto out;
 
-		ip_addr.l2tp_family = AF_INET;
-		ip_addr.l2tp_addr = cfg->peer_ip;
-		ip_addr.l2tp_conn_id = peer_tunnel_id;
-		err = kernel_connect(sock, (struct sockaddr *) &ip_addr, sizeof(ip_addr), 0);
-		if (err < 0)
-			goto out;
+			ip6_addr.l2tp_family = AF_INET6;
+			memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6,
+			       sizeof(ip6_addr.l2tp_addr));
+			ip6_addr.l2tp_conn_id = peer_tunnel_id;
+			err = kernel_connect(sock,
+					     (struct sockaddr *) &ip6_addr,
+					     sizeof(ip6_addr), 0);
+			if (err < 0)
+				goto out;
+		} else
+#endif
+		{
+			err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP,
+					  sockp);
+			if (err < 0)
+				goto out;
 
+			sock = *sockp;
+
+			memset(&ip_addr, 0, sizeof(ip_addr));
+			ip_addr.l2tp_family = AF_INET;
+			ip_addr.l2tp_addr = cfg->local_ip;
+			ip_addr.l2tp_conn_id = tunnel_id;
+			err = kernel_bind(sock, (struct sockaddr *) &ip_addr,
+					  sizeof(ip_addr));
+			if (err < 0)
+				goto out;
+
+			ip_addr.l2tp_family = AF_INET;
+			ip_addr.l2tp_addr = cfg->peer_ip;
+			ip_addr.l2tp_conn_id = peer_tunnel_id;
+			err = kernel_connect(sock, (struct sockaddr *) &ip_addr,
+					     sizeof(ip_addr), 0);
+			if (err < 0)
+				goto out;
+		}
 		break;
 
 	default:
-- 
1.7.0.4

Re: [PATCH 00/10] l2tp: misc fixes and add L2TPv3 IP encap over IPv6

[David Miller]

From: James Chapman <jchapman@katalix.com>
Date: Fri, 20 Apr 2012 10:02:43 +0100

> This patch series includes several L2TP fixes / cleanups and adds
> L2TPv3 IP encapsulation support for IPv6.
> 
> Patches 4-10 depend on Benjamin LaHaise's L2TP UDP IPv6 patches which
> have already been submitted for review. Patches 1-3 are not IPv6
> related so can be reviewed / applied now.

They aren't in review state, they're in "changed requested" state
because they are obviously broken and need changes since you hit
all of those checksum problems on loopback when you tested it.

Never submit patch sets against another patch series that is going
to have to go through changes before it goes into the tree.

I'm dropping this entire set, resubmit after Ben fixes the checksum
problems and does a new submission.

Re: [PATCH 00/10] l2tp: misc fixes and add L2TPv3 IP encap over IPv6

[James Chapman]

On 22/04/12 05:29, David Miller wrote:
> From: James Chapman <jchapman@katalix.com>
> Date: Fri, 20 Apr 2012 10:02:43 +0100
> 
>> This patch series includes several L2TP fixes / cleanups and adds
>> L2TPv3 IP encapsulation support for IPv6.
>>
>> Patches 4-10 depend on Benjamin LaHaise's L2TP UDP IPv6 patches which
>> have already been submitted for review. Patches 1-3 are not IPv6
>> related so can be reviewed / applied now.
> 
> They aren't in review state, they're in "changed requested" state
> because they are obviously broken and need changes since you hit
> all of those checksum problems on loopback when you tested it.
> 
> Never submit patch sets against another patch series that is going
> to have to go through changes before it goes into the tree.
> 
> I'm dropping this entire set, resubmit after Ben fixes the checksum
> problems and does a new submission.

Ok.

Ben, if I can help with the loopback checksum issue, please let me know.


-- 
James Chapman
Katalix Systems Ltd
http://www.katalix.com
Catalysts for your Embedded Linux software development

Re: [PATCH 00/10] l2tp: misc fixes and add L2TPv3 IP encap over IPv6

[Benjamin LaHaise]

On Mon, Apr 23, 2012 at 10:21:23AM +0100, James Chapman wrote:
> Ok.
> 
> Ben, if I can help with the loopback checksum issue, please let me know.

The fix is pretty simple; in l2tp_xmit_ipv6_csum, change CHECKSUM_COMPLETE 
to CHECKSUM_UNNECESSARY (or CHECKSUM_NONE), as that will prevent the 
incoming sk_buff's ->csum value from being used (it's not correct).  I'm 
travelling at the moment, so I may not have time to respin the patch until 
Wednesday, but if I can, I will try to find the time this evening. 

		-ben
-- 
"Thought is the essence of where you are now."