1 files changed, 614 insertions, 373 deletions

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index c64ce0a0bb0..bea25904320 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -18,6 +18,8 @@
  * published by the Free Software Foundation.
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/module.h>
 #include <linux/string.h>
 #include <linux/list.h>
@@ -53,9 +55,13 @@
 #include <net/inet_common.h>
 #include <net/xfrm.h>
 #include <net/protocol.h>
+#include <net/inet6_connection_sock.h>
+#include <net/inet_ecn.h>
+#include <net/ip6_route.h>
+#include <net/ip6_checksum.h>
 
 #include <asm/byteorder.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
 
 #include "l2tp_core.h"
 
@@ -82,12 +88,6 @@
 /* Default trace flags */
 #define L2TP_DEFAULT_DEBUG_FLAGS	0
 
-#define PRINTK(_mask, _type, _lvl, _fmt, args...)			\
-	do {								\
-		if ((_mask) & (_type))					\
-			printk(_lvl "L2TP: " _fmt, ##args);		\
-	} while (0)
-
 /* Private data stored for received packets in the skb.
  */
 struct l2tp_skb_cb {
@@ -101,6 +101,7 @@ struct l2tp_skb_cb {
 
 static atomic_t l2tp_tunnel_count;
 static atomic_t l2tp_session_count;
+static struct workqueue_struct *l2tp_wq;
 
 /* per-net private data for this module */
 static unsigned int l2tp_net_id;
@@ -111,9 +112,12 @@ struct l2tp_net {
 	spinlock_t l2tp_session_hlist_lock;
 };
 
-static void l2tp_session_set_header_len(struct l2tp_session *session, int version);
 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
-static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
+
+static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk)
+{
+	return sk->sk_user_data;
+}
 
 static inline struct l2tp_net *l2tp_pernet(struct net *net)
 {
@@ -122,7 +126,6 @@ static inline struct l2tp_net *l2tp_pernet(struct net *net)
 	return net_generic(net, l2tp_net_id);
 }
 
-
 /* Tunnel reference counts. Incremented per session that is added to
  * the tunnel.
  */
@@ -137,14 +140,20 @@ static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel)
 		l2tp_tunnel_free(tunnel);
 }
 #ifdef L2TP_REFCNT_DEBUG
-#define l2tp_tunnel_inc_refcount(_t) do { \
-		printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
-		l2tp_tunnel_inc_refcount_1(_t);				\
-	} while (0)
-#define l2tp_tunnel_dec_refcount(_t) do { \
-		printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \
-		l2tp_tunnel_dec_refcount_1(_t);				\
-	} while (0)
+#define l2tp_tunnel_inc_refcount(_t)					\
+do {									\
+	pr_debug("l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n",	\
+		 __func__, __LINE__, (_t)->name,			\
+		 atomic_read(&_t->ref_count));				\
+	l2tp_tunnel_inc_refcount_1(_t);					\
+} while (0)
+#define l2tp_tunnel_dec_refcount(_t)
+do {									\
+	pr_debug("l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n",	\
+		 __func__, __LINE__, (_t)->name,			\
+		 atomic_read(&_t->ref_count));				\
+	l2tp_tunnel_dec_refcount_1(_t);					\
+} while (0)
 #else
 #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t)
 #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t)
@@ -162,6 +171,51 @@ l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id)
 
 }
 
+/* Lookup the tunnel socket, possibly involving the fs code if the socket is
+ * owned by userspace.  A struct sock returned from this function must be
+ * released using l2tp_tunnel_sock_put once you're done with it.
+ */
+static struct sock *l2tp_tunnel_sock_lookup(struct l2tp_tunnel *tunnel)
+{
+	int err = 0;
+	struct socket *sock = NULL;
+	struct sock *sk = NULL;
+
+	if (!tunnel)
+		goto out;
+
+	if (tunnel->fd >= 0) {
+		/* Socket is owned by userspace, who might be in the process
+		 * of closing it.  Look the socket up using the fd to ensure
+		 * consistency.
+		 */
+		sock = sockfd_lookup(tunnel->fd, &err);
+		if (sock)
+			sk = sock->sk;
+	} else {
+		/* Socket is owned by kernelspace */
+		sk = tunnel->sock;
+		sock_hold(sk);
+	}
+
+out:
+	return sk;
+}
+
+/* Drop a reference to a tunnel socket obtained via. l2tp_tunnel_sock_put */
+static void l2tp_tunnel_sock_put(struct sock *sk)
+{
+	struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
+	if (tunnel) {
+		if (tunnel->fd >= 0) {
+			/* Socket is owned by userspace */
+			sockfd_put(sk->sk_socket);
+		}
+		sock_put(sk);
+	}
+	sock_put(sk);
+}
+
 /* Lookup a session by id in the global session list
  */
 static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
@@ -170,10 +224,9 @@ static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
 	struct hlist_head *session_list =
 		l2tp_session_id_hash_2(pn, session_id);
 	struct l2tp_session *session;
-	struct hlist_node *walk;
 
 	rcu_read_lock_bh();
-	hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) {
+	hlist_for_each_entry_rcu(session, session_list, global_hlist) {
 		if (session->session_id == session_id) {
 			rcu_read_unlock_bh();
 			return session;
@@ -202,7 +255,6 @@ struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunn
 {
 	struct hlist_head *session_list;
 	struct l2tp_session *session;
-	struct hlist_node *walk;
 
 	/* In L2TPv3, session_ids are unique over all tunnels and we
 	 * sometimes need to look them up before we know the
@@ -213,7 +265,7 @@ struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunn
 
 	session_list = l2tp_session_id_hash(tunnel, session_id);
 	read_lock_bh(&tunnel->hlist_lock);
-	hlist_for_each_entry(session, walk, session_list, hlist) {
+	hlist_for_each_entry(session, session_list, hlist) {
 		if (session->session_id == session_id) {
 			read_unlock_bh(&tunnel->hlist_lock);
 			return session;
@@ -228,13 +280,12 @@ EXPORT_SYMBOL_GPL(l2tp_session_find);
 struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth)
 {
 	int hash;
-	struct hlist_node *walk;
 	struct l2tp_session *session;
 	int count = 0;
 
 	read_lock_bh(&tunnel->hlist_lock);
 	for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
-		hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) {
+		hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
 			if (++count > nth) {
 				read_unlock_bh(&tunnel->hlist_lock);
 				return session;
@@ -255,12 +306,11 @@ struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname)
 {
 	struct l2tp_net *pn = l2tp_pernet(net);
 	int hash;
-	struct hlist_node *walk;
 	struct l2tp_session *session;
 
 	rcu_read_lock_bh();
 	for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) {
-		hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) {
+		hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
 			if (!strcmp(session->ifname, ifname)) {
 				rcu_read_unlock_bh();
 				return session;
@@ -331,11 +381,11 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk
 	skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
 		if (L2TP_SKB_CB(skbp)->ns > ns) {
 			__skb_queue_before(&session->reorder_q, skbp, skb);
-			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-			       "%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++;
+			l2tp_dbg(session, L2TP_MSG_SEQ,
+				 "%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));
+			atomic_long_inc(&session->stats.rx_oos_packets);
 			goto out;
 		}
 	}
@@ -358,21 +408,18 @@ static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *
 	 */
 	skb_orphan(skb);
 
-	tunnel->stats.rx_packets++;
-	tunnel->stats.rx_bytes += length;
-	session->stats.rx_packets++;
-	session->stats.rx_bytes += length;
+	atomic_long_inc(&tunnel->stats.rx_packets);
+	atomic_long_add(length, &tunnel->stats.rx_bytes);
+	atomic_long_inc(&session->stats.rx_packets);
+	atomic_long_add(length, &session->stats.rx_bytes);
 
 	if (L2TP_SKB_CB(skb)->has_seq) {
 		/* Bump our Nr */
 		session->nr++;
-		if (tunnel->version == L2TP_HDR_VER_2)
-			session->nr &= 0xffff;
-		else
-			session->nr &= 0xffffff;
+		session->nr &= session->nr_max;
 
-		PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-		       "%s: updated nr to %hu\n", session->name, session->nr);
+		l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated nr to %hu\n",
+			 session->name, session->nr);
 	}
 
 	/* call private receive handler */
@@ -397,17 +444,18 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
 	 * expect to send up next, dequeue it and any other
 	 * in-sequence packets behind it.
 	 */
+start:
 	spin_lock_bh(&session->reorder_q.lock);
 	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++;
-			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",
-			       session->name, L2TP_SKB_CB(skb)->ns,
-			       L2TP_SKB_CB(skb)->length, session->nr,
-			       skb_queue_len(&session->reorder_q));
+			atomic_long_inc(&session->stats.rx_seq_discards);
+			atomic_long_inc(&session->stats.rx_errors);
+			l2tp_dbg(session, L2TP_MSG_SEQ,
+				 "%s: oos pkt %u len %d discarded (too old), waiting for %u, reorder_q_len=%d\n",
+				 session->name, L2TP_SKB_CB(skb)->ns,
+				 L2TP_SKB_CB(skb)->length, session->nr,
+				 skb_queue_len(&session->reorder_q));
+			session->reorder_skip = 1;
 			__skb_unlink(skb, &session->reorder_q);
 			kfree_skb(skb);
 			if (session->deref)
@@ -416,13 +464,20 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
 		}
 
 		if (L2TP_SKB_CB(skb)->has_seq) {
+			if (session->reorder_skip) {
+				l2tp_dbg(session, L2TP_MSG_SEQ,
+					 "%s: advancing nr to next pkt: %u -> %u",
+					 session->name, session->nr,
+					 L2TP_SKB_CB(skb)->ns);
+				session->reorder_skip = 0;
+				session->nr = L2TP_SKB_CB(skb)->ns;
+			}
 			if (L2TP_SKB_CB(skb)->ns != session->nr) {
-				PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-				       "%s: holding oos pkt %u len %d, "
-				       "waiting for %u, reorder_q_len=%d\n",
-				       session->name, L2TP_SKB_CB(skb)->ns,
-				       L2TP_SKB_CB(skb)->length, session->nr,
-				       skb_queue_len(&session->reorder_q));
+				l2tp_dbg(session, L2TP_MSG_SEQ,
+					 "%s: holding oos pkt %u len %d, waiting for %u, reorder_q_len=%d\n",
+					 session->name, L2TP_SKB_CB(skb)->ns,
+					 L2TP_SKB_CB(skb)->length, session->nr,
+					 skb_queue_len(&session->reorder_q));
 				goto out;
 			}
 		}
@@ -433,35 +488,89 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
 		 */
 		spin_unlock_bh(&session->reorder_q.lock);
 		l2tp_recv_dequeue_skb(session, skb);
-		spin_lock_bh(&session->reorder_q.lock);
+		goto start;
 	}
 
 out:
 	spin_unlock_bh(&session->reorder_q.lock);
 }
 
-static inline int l2tp_verify_udp_checksum(struct sock *sk,
-					   struct sk_buff *skb)
+static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
 {
-	struct udphdr *uh = udp_hdr(skb);
-	u16 ulen = ntohs(uh->len);
-	struct inet_sock *inet;
-	__wsum psum;
+	u32 nws;
 
-	if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
-		return 0;
+	if (nr >= session->nr)
+		nws = nr - session->nr;
+	else
+		nws = (session->nr_max + 1) - (session->nr - nr);
 
-	inet = inet_sk(sk);
-	psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen,
-				  IPPROTO_UDP, 0);
+	return nws < session->nr_window_size;
+}
+
+/* If packet has sequence numbers, queue it if acceptable. Returns 0 if
+ * acceptable, else non-zero.
+ */
+static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb)
+{
+	if (!l2tp_seq_check_rx_window(session, L2TP_SKB_CB(skb)->ns)) {
+		/* Packet sequence number is outside allowed window.
+		 * Discard it.
+		 */
+		l2tp_dbg(session, L2TP_MSG_SEQ,
+			 "%s: pkt %u len %d discarded, outside window, nr=%u\n",
+			 session->name, L2TP_SKB_CB(skb)->ns,
+			 L2TP_SKB_CB(skb)->length, session->nr);
+		goto discard;
+	}
 
-	if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
-	    !csum_fold(csum_add(psum, skb->csum)))
-		return 0;
+	if (session->reorder_timeout != 0) {
+		/* Packet reordering enabled. Add skb to session's
+		 * reorder queue, in order of ns.
+		 */
+		l2tp_recv_queue_skb(session, skb);
+		goto out;
+	}
 
-	skb->csum = psum;
+	/* Packet reordering disabled. Discard out-of-sequence packets, while
+	 * tracking the number if in-sequence packets after the first OOS packet
+	 * is seen. After nr_oos_count_max in-sequence packets, reset the
+	 * sequence number to re-enable packet reception.
+	 */
+	if (L2TP_SKB_CB(skb)->ns == session->nr) {
+		skb_queue_tail(&session->reorder_q, skb);
+	} else {
+		u32 nr_oos = L2TP_SKB_CB(skb)->ns;
+		u32 nr_next = (session->nr_oos + 1) & session->nr_max;
 
-	return __skb_checksum_complete(skb);
+		if (nr_oos == nr_next)
+			session->nr_oos_count++;
+		else
+			session->nr_oos_count = 0;
+
+		session->nr_oos = nr_oos;
+		if (session->nr_oos_count > session->nr_oos_count_max) {
+			session->reorder_skip = 1;
+			l2tp_dbg(session, L2TP_MSG_SEQ,
+				 "%s: %d oos packets received. Resetting sequence numbers\n",
+				 session->name, session->nr_oos_count);
+		}
+		if (!session->reorder_skip) {
+			atomic_long_inc(&session->stats.rx_seq_discards);
+			l2tp_dbg(session, L2TP_MSG_SEQ,
+				 "%s: oos pkt %u len %d discarded, waiting for %u, reorder_q_len=%d\n",
+				 session->name, L2TP_SKB_CB(skb)->ns,
+				 L2TP_SKB_CB(skb)->length, session->nr,
+				 skb_queue_len(&session->reorder_q));
+			goto discard;
+		}
+		skb_queue_tail(&session->reorder_q, skb);
+	}
+
+out:
+	return 0;
+
+discard:
+	return 1;
 }
 
 /* Do receive processing of L2TP data frames. We handle both L2TPv2
@@ -543,10 +652,11 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 	/* Parse and check optional cookie */
 	if (session->peer_cookie_len > 0) {
 		if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) {
-			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++;
+			l2tp_info(tunnel, L2TP_MSG_DATA,
+				  "%s: cookie mismatch (%u/%u). Discarding.\n",
+				  tunnel->name, tunnel->tunnel_id,
+				  session->session_id);
+			atomic_long_inc(&session->stats.rx_cookie_discards);
 			goto discard;
 		}
 		ptr += session->peer_cookie_len;
@@ -572,9 +682,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 			L2TP_SKB_CB(skb)->ns = ns;
 			L2TP_SKB_CB(skb)->has_seq = 1;
 
-			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-			       "%s: recv data ns=%u, nr=%u, session nr=%u\n",
-			       session->name, ns, nr, session->nr);
+			l2tp_dbg(session, L2TP_MSG_SEQ,
+				 "%s: recv data ns=%u, nr=%u, session nr=%u\n",
+				 session->name, ns, nr, session->nr);
 		}
 	} else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) {
 		u32 l2h = ntohl(*(__be32 *) ptr);
@@ -586,9 +696,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 			L2TP_SKB_CB(skb)->ns = ns;
 			L2TP_SKB_CB(skb)->has_seq = 1;
 
-			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-			       "%s: recv data ns=%u, session nr=%u\n",
-			       session->name, ns, session->nr);
+			l2tp_dbg(session, L2TP_MSG_SEQ,
+				 "%s: recv data ns=%u, session nr=%u\n",
+				 session->name, ns, session->nr);
 		}
 	}
 
@@ -601,9 +711,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 		 * configure it so.
 		 */
 		if ((!session->lns_mode) && (!session->send_seq)) {
-			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
-			       "%s: requested to enable seq numbers by LNS\n",
-			       session->name);
+			l2tp_info(session, L2TP_MSG_SEQ,
+				  "%s: requested to enable seq numbers by LNS\n",
+				  session->name);
 			session->send_seq = -1;
 			l2tp_session_set_header_len(session, tunnel->version);
 		}
@@ -612,10 +722,10 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 		 * If user has configured mandatory sequence numbers, discard.
 		 */
 		if (session->recv_seq) {
-			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++;
+			l2tp_warn(session, L2TP_MSG_SEQ,
+				  "%s: recv data has no seq numbers when required. Discarding.\n",
+				  session->name);
+			atomic_long_inc(&session->stats.rx_seq_discards);
 			goto discard;
 		}
 
@@ -625,16 +735,16 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 		 * LAC is broken. Discard the frame.
 		 */
 		if ((!session->lns_mode) && (session->send_seq)) {
-			PRINTK(session->debug, L2TP_MSG_SEQ, KERN_INFO,
-			       "%s: requested to disable seq numbers by LNS\n",
-			       session->name);
+			l2tp_info(session, L2TP_MSG_SEQ,
+				  "%s: requested to disable seq numbers by LNS\n",
+				  session->name);
 			session->send_seq = 0;
 			l2tp_session_set_header_len(session, tunnel->version);
 		} else if (session->send_seq) {
-			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++;
+			l2tp_warn(session, L2TP_MSG_SEQ,
+				  "%s: recv data has no seq numbers when required. Discarding.\n",
+				  session->name);
+			atomic_long_inc(&session->stats.rx_seq_discards);
 			goto discard;
 		}
 	}
@@ -678,27 +788,8 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 	 * enabled. Saved L2TP protocol info is stored in skb->sb[].
 	 */
 	if (L2TP_SKB_CB(skb)->has_seq) {
-		if (session->reorder_timeout != 0) {
-			/* Packet reordering enabled. Add skb to session's
-			 * reorder queue, in order of ns.
-			 */
-			l2tp_recv_queue_skb(session, skb);
-		} else {
-			/* Packet reordering disabled. Discard out-of-sequence
-			 * packets
-			 */
-			if (L2TP_SKB_CB(skb)->ns != session->nr) {
-				session->stats.rx_seq_discards++;
-				PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-				       "%s: oos pkt %u len %d discarded, "
-				       "waiting for %u, reorder_q_len=%d\n",
-				       session->name, L2TP_SKB_CB(skb)->ns,
-				       L2TP_SKB_CB(skb)->length, session->nr,
-				       skb_queue_len(&session->reorder_q));
-				goto discard;
-			}
-			skb_queue_tail(&session->reorder_q, skb);
-		}
+		if (l2tp_recv_data_seq(session, skb))
+			goto discard;
 	} else {
 		/* No sequence numbers. Add the skb to the tail of the
 		 * reorder queue. This ensures that it will be
@@ -715,7 +806,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 	return;
 
 discard:
-	session->stats.rx_errors++;
+	atomic_long_inc(&session->stats.rx_errors);
 	kfree_skb(skb);
 
 	if (session->deref)
@@ -725,6 +816,23 @@ discard:
 }
 EXPORT_SYMBOL(l2tp_recv_common);
 
+/* Drop skbs from the session's reorder_q
+ */
+int l2tp_session_queue_purge(struct l2tp_session *session)
+{
+	struct sk_buff *skb = NULL;
+	BUG_ON(!session);
+	BUG_ON(session->magic != L2TP_SESSION_MAGIC);
+	while ((skb = skb_dequeue(&session->reorder_q))) {
+		atomic_long_inc(&session->stats.rx_errors);
+		kfree_skb(skb);
+		if (session->deref)
+			(*session->deref)(session);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(l2tp_session_queue_purge);
+
 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
  * here. The skb is not on a list when we get here.
  * Returns 0 if the packet was a data packet and was successfully passed on.
@@ -738,51 +846,44 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 	unsigned char *ptr, *optr;
 	u16 hdrflags;
 	u32 tunnel_id, session_id;
-	int offset;
 	u16 version;
 	int length;
 
-	if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
-		goto discard_bad_csum;
+	/* UDP has verifed checksum */
 
 	/* UDP always verifies the packet length. */
 	__skb_pull(skb, sizeof(struct udphdr));
 
 	/* Short packet? */
 	if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) {
-		PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
-		       "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
+		l2tp_info(tunnel, L2TP_MSG_DATA,
+			  "%s: recv short packet (len=%d)\n",
+			  tunnel->name, skb->len);
 		goto error;
 	}
 
-	/* Point to L2TP header */
-	optr = ptr = skb->data;
-
 	/* Trace packet contents, if enabled */
 	if (tunnel->debug & L2TP_MSG_DATA) {
 		length = min(32u, skb->len);
 		if (!pskb_may_pull(skb, length))
 			goto error;
 
-		printk(KERN_DEBUG "%s: recv: ", tunnel->name);
-
-		offset = 0;
-		do {
-			printk(" %02X", ptr[offset]);
-		} while (++offset < length);
-
-		printk("\n");
+		pr_debug("%s: recv\n", tunnel->name);
+		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
 	}
 
+	/* Point to L2TP header */
+	optr = ptr = skb->data;
+
 	/* Get L2TP header flags */
 	hdrflags = ntohs(*(__be16 *) ptr);
 
 	/* Check protocol version */
 	version = hdrflags & L2TP_HDR_VER_MASK;
 	if (version != tunnel->version) {
-		PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
-		       "%s: recv protocol version mismatch: got %d expected %d\n",
-		       tunnel->name, version, tunnel->version);
+		l2tp_info(tunnel, L2TP_MSG_DATA,
+			  "%s: recv protocol version mismatch: got %d expected %d\n",
+			  tunnel->name, version, tunnel->version);
 		goto error;
 	}
 
@@ -791,8 +892,9 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 
 	/* If type is control packet, it is handled by userspace. */
 	if (hdrflags & L2TP_HDRFLAG_T) {
-		PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
-		       "%s: recv control packet, len=%d\n", tunnel->name, length);
+		l2tp_dbg(tunnel, L2TP_MSG_DATA,
+			 "%s: recv control packet, len=%d\n",
+			 tunnel->name, length);
 		goto error;
 	}
 
@@ -820,9 +922,9 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 	session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id);
 	if (!session || !session->recv_skb) {
 		/* Not found? Pass to userspace to deal with */
-		PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
-		       "%s: no session found (%u/%u). Passing up.\n",
-		       tunnel->name, tunnel_id, session_id);
+		l2tp_info(tunnel, L2TP_MSG_DATA,
+			  "%s: no session found (%u/%u). Passing up.\n",
+			  tunnel->name, tunnel_id, session_id);
 		goto error;
 	}
 
@@ -830,14 +932,6 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 
 	return 0;
 
-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++;
-	kfree_skb(skb);
-
-	return 0;
-
 error:
 	/* Put UDP header back */
 	__skb_push(skb, sizeof(struct udphdr));
@@ -859,8 +953,8 @@ int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 	if (tunnel == NULL)
 		goto pass_up;
 
-	PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG,
-	       "%s: received %d bytes\n", tunnel->name, skb->len);
+	l2tp_dbg(tunnel, L2TP_MSG_DATA, "%s: received %d bytes\n",
+		 tunnel->name, skb->len);
 
 	if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook))
 		goto pass_up_put;
@@ -902,8 +996,8 @@ static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
 		*bufp++ = 0;
 		session->ns++;
 		session->ns &= 0xffff;
-		PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-		       "%s: updated ns to %u\n", session->name, session->ns);
+		l2tp_dbg(session, L2TP_MSG_SEQ, "%s: updated ns to %u\n",
+			 session->name, session->ns);
 	}
 
 	return bufp - optr;
@@ -939,8 +1033,9 @@ static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
 				l2h = 0x40000000 | session->ns;
 				session->ns++;
 				session->ns &= 0xffffff;
-				PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
-				       "%s: updated ns to %u\n", session->name, session->ns);
+				l2tp_dbg(session, L2TP_MSG_SEQ,
+					 "%s: updated ns to %u\n",
+					 session->name, session->ns);
 			}
 
 			*((__be32 *) bufp) = htonl(l2h);
@@ -954,7 +1049,7 @@ static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
 }
 
 static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
-			  size_t data_len)
+			  struct flowi *fl, size_t data_len)
 {
 	struct l2tp_tunnel *tunnel = session->tunnel;
 	unsigned int len = skb->len;
@@ -962,64 +1057,44 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
 
 	/* Debug */
 	if (session->send_seq)
-		PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
-		       "%s: send %Zd bytes, ns=%u\n", session->name,
-		       data_len, session->ns - 1);
+		l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes, ns=%u\n",
+			 session->name, data_len, session->ns - 1);
 	else
-		PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
-		       "%s: send %Zd bytes\n", session->name, data_len);
+		l2tp_dbg(session, L2TP_MSG_DATA, "%s: send %Zd bytes\n",
+			 session->name, data_len);
 
 	if (session->debug & L2TP_MSG_DATA) {
-		int i;
 		int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
 		unsigned char *datap = skb->data + uhlen;
 
-		printk(KERN_DEBUG "%s: xmit:", session->name);
-		for (i = 0; i < (len - uhlen); i++) {
-			printk(" %02X", *datap++);
-			if (i == 31) {
-				printk(" ...");
-				break;
-			}
-		}
-		printk("\n");
+		pr_debug("%s: xmit\n", session->name);
+		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET,
+				     datap, min_t(size_t, 32, len - uhlen));
 	}
 
 	/* Queue the packet to IP for output */
-	skb->local_df = 1;
-	error = ip_queue_xmit(skb);
+	skb->ignore_df = 1;
+#if IS_ENABLED(CONFIG_IPV6)
+	if (tunnel->sock->sk_family == PF_INET6 && !tunnel->v4mapped)
+		error = inet6_csk_xmit(tunnel->sock, skb, NULL);
+	else
+#endif
+		error = ip_queue_xmit(tunnel->sock, skb, fl);
 
 	/* Update stats */
 	if (error >= 0) {
-		tunnel->stats.tx_packets++;
-		tunnel->stats.tx_bytes += len;
-		session->stats.tx_packets++;
-		session->stats.tx_bytes += len;
+		atomic_long_inc(&tunnel->stats.tx_packets);
+		atomic_long_add(len, &tunnel->stats.tx_bytes);
+		atomic_long_inc(&session->stats.tx_packets);
+		atomic_long_add(len, &session->stats.tx_bytes);
 	} else {
-		tunnel->stats.tx_errors++;
-		session->stats.tx_errors++;
+		atomic_long_inc(&tunnel->stats.tx_errors);
+		atomic_long_inc(&session->stats.tx_errors);
 	}
 
 	return 0;
 }
 
-/* Automatically called when the skb is freed.
- */
-static void l2tp_sock_wfree(struct sk_buff *skb)
-{
-	sock_put(skb->sk);
-}
-
-/* For data skbs that we transmit, we associate with the tunnel socket
- * but don't do accounting.
- */
-static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
-{
-	sock_hold(sk);
-	skb->sk = sk;
-	skb->destructor = l2tp_sock_wfree;
-}
-
 /* If caller requires the skb to have a ppp header, the header must be
  * inserted in the skb data before calling this function.
  */
@@ -1028,14 +1103,13 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
 	int data_len = skb->len;
 	struct l2tp_tunnel *tunnel = session->tunnel;
 	struct sock *sk = tunnel->sock;
+	struct flowi *fl;
 	struct udphdr *uh;
 	struct inet_sock *inet;
-	__wsum csum;
-	int old_headroom;
-	int new_headroom;
 	int headroom;
 	int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
 	int udp_len;
+	int ret = NET_XMIT_SUCCESS;
 
 	/* Check that there's enough headroom in the skb to insert IP,
 	 * UDP and L2TP headers. If not enough, expand it to
@@ -1043,13 +1117,10 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
 	 */
 	headroom = NET_SKB_PAD + sizeof(struct iphdr) +
 		uhlen + hdr_len;
-	old_headroom = skb_headroom(skb);
-	if (skb_cow_head(skb, headroom))
-		goto abort;
-
-	new_headroom = skb_headroom(skb);
-	skb_orphan(skb);
-	skb->truesize += new_headroom - old_headroom;
+	if (skb_cow_head(skb, headroom)) {
+		kfree_skb(skb);
+		return NET_XMIT_DROP;
+	}
 
 	/* Setup L2TP header */
 	session->build_header(session, __skb_push(skb, hdr_len));
@@ -1060,14 +1131,22 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
 			      IPSKB_REROUTED);
 	nf_reset(skb);
 
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		kfree_skb(skb);
+		ret = NET_XMIT_DROP;
+		goto out_unlock;
+	}
+
 	/* Get routing info from the tunnel socket */
 	skb_dst_drop(skb);
-	skb_dst_set(skb, dst_clone(__sk_dst_get(sk)));
+	skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
 
+	inet = inet_sk(sk);
+	fl = &inet->cork.fl;
 	switch (tunnel->encap) {
 	case L2TP_ENCAPTYPE_UDP:
 		/* Setup UDP header */
-		inet = inet_sk(sk);
 		__skb_push(skb, sizeof(*uh));
 		skb_reset_transport_header(skb);
 		uh = udp_hdr(skb);
@@ -1075,40 +1154,28 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
 		uh->dest = inet->inet_dport;
 		udp_len = uhlen + hdr_len + data_len;
 		uh->len = htons(udp_len);
-		uh->check = 0;
 
 		/* Calculate UDP checksum if configured to do so */
-		if (sk->sk_no_check == UDP_CSUM_NOXMIT)
-			skb->ip_summed = CHECKSUM_NONE;
-		else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
-			 (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
-			skb->ip_summed = CHECKSUM_COMPLETE;
-			csum = skb_checksum(skb, 0, udp_len, 0);
-			uh->check = csum_tcpudp_magic(inet->inet_saddr,
-						      inet->inet_daddr,
-						      udp_len, IPPROTO_UDP, csum);
-			if (uh->check == 0)
-				uh->check = CSUM_MANGLED_0;
-		} else {
-			skb->ip_summed = CHECKSUM_PARTIAL;
-			skb->csum_start = skb_transport_header(skb) - skb->head;
-			skb->csum_offset = offsetof(struct udphdr, check);
-			uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
-						       inet->inet_daddr,
-						       udp_len, IPPROTO_UDP, 0);
-		}
+#if IS_ENABLED(CONFIG_IPV6)
+		if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
+			udp6_set_csum(udp_get_no_check6_tx(sk),
+				      skb, &inet6_sk(sk)->saddr,
+				      &sk->sk_v6_daddr, udp_len);
+		else
+#endif
+		udp_set_csum(sk->sk_no_check_tx, skb, inet->inet_saddr,
+			     inet->inet_daddr, udp_len);
 		break;
 
 	case L2TP_ENCAPTYPE_IP:
 		break;
 	}
 
-	l2tp_skb_set_owner_w(skb, sk);
-
-	l2tp_xmit_core(session, skb, data_len);
+	l2tp_xmit_core(session, skb, fl, data_len);
+out_unlock:
+	bh_unlock_sock(sk);
 
-abort:
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
 
@@ -1122,47 +1189,52 @@ EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
  */
 static void l2tp_tunnel_destruct(struct sock *sk)
 {
-	struct l2tp_tunnel *tunnel;
+	struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);
+	struct l2tp_net *pn;
 
-	tunnel = sk->sk_user_data;
 	if (tunnel == NULL)
 		goto end;
 
-	PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
-	       "%s: closing...\n", tunnel->name);
+	l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
 
-	/* Close all sessions */
-	l2tp_tunnel_closeall(tunnel);
 
+	/* Disable udp encapsulation */
 	switch (tunnel->encap) {
 	case L2TP_ENCAPTYPE_UDP:
 		/* No longer an encapsulation socket. See net/ipv4/udp.c */
 		(udp_sk(sk))->encap_type = 0;
 		(udp_sk(sk))->encap_rcv = NULL;
+		(udp_sk(sk))->encap_destroy = NULL;
 		break;
 	case L2TP_ENCAPTYPE_IP:
 		break;
 	}
 
 	/* Remove hooks into tunnel socket */
-	tunnel->sock = NULL;
 	sk->sk_destruct = tunnel->old_sk_destruct;
 	sk->sk_user_data = NULL;
+	tunnel->sock = NULL;
 
-	/* Call the original destructor */
-	if (sk->sk_destruct)
-		(*sk->sk_destruct)(sk);
+	/* Remove the tunnel struct from the tunnel list */
+	pn = l2tp_pernet(tunnel->l2tp_net);
+	spin_lock_bh(&pn->l2tp_tunnel_list_lock);
+	list_del_rcu(&tunnel->list);
+	spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
+	atomic_dec(&l2tp_tunnel_count);
 
-	/* We're finished with the socket */
+	l2tp_tunnel_closeall(tunnel);
 	l2tp_tunnel_dec_refcount(tunnel);
 
+	/* Call the original destructor */
+	if (sk->sk_destruct)
+		(*sk->sk_destruct)(sk);
 end:
 	return;
 }
 
 /* When the tunnel is closed, all the attached sessions need to go too.
  */
-static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
+void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
 {
 	int hash;
 	struct hlist_node *walk;
@@ -1171,8 +1243,8 @@ static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel)
 
 	BUG_ON(tunnel == NULL);
 
-	PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
-	       "%s: closing all sessions...\n", tunnel->name);
+	l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
+		  tunnel->name);
 
 	write_lock_bh(&tunnel->hlist_lock);
 	for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
@@ -1180,30 +1252,18 @@ again:
 		hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
 			session = hlist_entry(walk, struct l2tp_session, hlist);
 
-			PRINTK(session->debug, L2TP_MSG_CONTROL, KERN_INFO,
-			       "%s: closing session\n", session->name);
+			l2tp_info(session, L2TP_MSG_CONTROL,
+				  "%s: closing session\n", session->name);
 
 			hlist_del_init(&session->hlist);
 
-			/* Since we should hold the sock lock while
-			 * doing any unbinding, we need to release the
-			 * lock we're holding before taking that lock.
-			 * Hold a reference to the sock so it doesn't
-			 * disappear as we're jumping between locks.
-			 */
 			if (session->ref != NULL)
 				(*session->ref)(session);
 
 			write_unlock_bh(&tunnel->hlist_lock);
 
-			if (tunnel->version != L2TP_HDR_VER_2) {
-				struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
-
-				spin_lock_bh(&pn->l2tp_session_hlist_lock);
-				hlist_del_init_rcu(&session->global_hlist);
-				spin_unlock_bh(&pn->l2tp_session_hlist_lock);
-				synchronize_rcu();
-			}
+			__l2tp_session_unhash(session);
+			l2tp_session_queue_purge(session);
 
 			if (session->session_close != NULL)
 				(*session->session_close)(session);
@@ -1211,6 +1271,8 @@ again:
 			if (session->deref != NULL)
 				(*session->deref)(session);
 
+			l2tp_session_dec_refcount(session);
+
 			write_lock_bh(&tunnel->hlist_lock);
 
 			/* Now restart from the beginning of this hash
@@ -1223,91 +1285,205 @@ again:
 	}
 	write_unlock_bh(&tunnel->hlist_lock);
 }
+EXPORT_SYMBOL_GPL(l2tp_tunnel_closeall);
+
+/* Tunnel socket destroy hook for UDP encapsulation */
+static void l2tp_udp_encap_destroy(struct sock *sk)
+{
+	struct l2tp_tunnel *tunnel = l2tp_sock_to_tunnel(sk);
+	if (tunnel) {
+		l2tp_tunnel_closeall(tunnel);
+		sock_put(sk);
+	}
+}
 
 /* Really kill the tunnel.
  * Come here only when all sessions have been cleared from the tunnel.
  */
 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
 {
-	struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
-
 	BUG_ON(atomic_read(&tunnel->ref_count) != 0);
 	BUG_ON(tunnel->sock != NULL);
+	l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name);
+	kfree_rcu(tunnel, rcu);
+}
 
-	PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO,
-	       "%s: free...\n", tunnel->name);
+/* Workqueue tunnel deletion function */
+static void l2tp_tunnel_del_work(struct work_struct *work)
+{
+	struct l2tp_tunnel *tunnel = NULL;
+	struct socket *sock = NULL;
+	struct sock *sk = NULL;
 
-	/* Remove from tunnel list */
-	spin_lock_bh(&pn->l2tp_tunnel_list_lock);
-	list_del_rcu(&tunnel->list);
-	spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
-	synchronize_rcu();
+	tunnel = container_of(work, struct l2tp_tunnel, del_work);
+	sk = l2tp_tunnel_sock_lookup(tunnel);
+	if (!sk)
+		return;
 
-	atomic_dec(&l2tp_tunnel_count);
-	kfree(tunnel);
+	sock = sk->sk_socket;
+
+	/* If the tunnel socket was created by userspace, then go through the
+	 * inet layer to shut the socket down, and let userspace close it.
+	 * Otherwise, if we created the socket directly within the kernel, use
+	 * the sk API to release it here.
+	 * In either case the tunnel resources are freed in the socket
+	 * destructor when the tunnel socket goes away.
+	 */
+	if (tunnel->fd >= 0) {
+		if (sock)
+			inet_shutdown(sock, 2);
+	} else {
+		if (sock)
+			kernel_sock_shutdown(sock, SHUT_RDWR);
+		sk_release_kernel(sk);
+	}
+
+	l2tp_tunnel_sock_put(sk);
 }
 
 /* Create a socket for the tunnel, if one isn't set up by
  * userspace. This is used for static tunnels where there is no
  * managing L2TP daemon.
+ *
+ * Since we don't want these sockets to keep a namespace alive by
+ * themselves, we drop the socket's namespace refcount after creation.
+ * These sockets are freed when the namespace exits using the pernet
+ * exit hook.
  */
-static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp)
+static int l2tp_tunnel_sock_create(struct net *net,
+				u32 tunnel_id,
+				u32 peer_tunnel_id,
+				struct l2tp_tunnel_cfg *cfg,
+				struct socket **sockp)
 {
 	int err = -EINVAL;
-	struct sockaddr_in udp_addr;
-	struct sockaddr_l2tpip ip_addr;
 	struct socket *sock = NULL;
+	struct sockaddr_in udp_addr = {0};
+	struct sockaddr_l2tpip ip_addr = {0};
+#if IS_ENABLED(CONFIG_IPV6)
+	struct sockaddr_in6 udp6_addr = {0};
+	struct sockaddr_l2tpip6 ip6_addr = {0};
+#endif
 
 	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_kern(AF_INET6, SOCK_DGRAM, 0, &sock);
+			if (err < 0)
+				goto out;
 
-		sock = *sockp;
+			sk_change_net(sock->sk, net);
 
-		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;
+			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;
+
+			if (cfg->udp6_zero_tx_checksums)
+				udp_set_no_check6_tx(sock->sk, true);
+			if (cfg->udp6_zero_rx_checksums)
+				udp_set_no_check6_rx(sock->sk, true);
+		} else
+#endif
+		{
+			err = sock_create_kern(AF_INET, SOCK_DGRAM, 0, &sock);
+			if (err < 0)
+				goto out;
+
+			sk_change_net(sock->sk, net);
+
+			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;
+			sock->sk->sk_no_check_tx = 1;
 
 		break;
 
 	case L2TP_ENCAPTYPE_IP:
-		err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, sockp);
-		if (err < 0)
-			goto out;
+#if IS_ENABLED(CONFIG_IPV6)
+		if (cfg->local_ip6 && cfg->peer_ip6) {
+			err = sock_create_kern(AF_INET6, SOCK_DGRAM,
+					  IPPROTO_L2TP, &sock);
+			if (err < 0)
+				goto out;
 
-		sock = *sockp;
+			sk_change_net(sock->sk, net);
 
-		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;
+			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_kern(AF_INET, SOCK_DGRAM,
+					  IPPROTO_L2TP, &sock);
+			if (err < 0)
+				goto out;
+
+			sk_change_net(sock->sk, net);
+
+			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:
@@ -1315,14 +1491,18 @@ static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2t
 	}
 
 out:
+	*sockp = sock;
 	if ((err < 0) && sock) {
-		sock_release(sock);
+		kernel_sock_shutdown(sock, SHUT_RDWR);
+		sk_release_kernel(sock->sk);
 		*sockp = NULL;
 	}
 
 	return err;
 }
 
+static struct lock_class_key l2tp_socket_class;
+
 int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp)
 {
 	struct l2tp_tunnel *tunnel = NULL;
@@ -1337,15 +1517,23 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	 * kernel socket.
 	 */
 	if (fd < 0) {
-		err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock);
+		err = l2tp_tunnel_sock_create(net, tunnel_id, peer_tunnel_id,
+				cfg, &sock);
 		if (err < 0)
 			goto err;
 	} else {
-		err = -EBADF;
 		sock = sockfd_lookup(fd, &err);
 		if (!sock) {
-			printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
+			pr_err("tunl %u: sockfd_lookup(fd=%d) returned %d\n",
 			       tunnel_id, fd, err);
+			err = -EBADF;
+			goto err;
+		}
+
+		/* Reject namespace mismatches */
+		if (!net_eq(sock_net(sock->sk), net)) {
+			pr_err("tunl %u: netns mismatch\n", tunnel_id);
+			err = -EINVAL;
 			goto err;
 		}
 	}
@@ -1360,7 +1548,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	case L2TP_ENCAPTYPE_UDP:
 		err = -EPROTONOSUPPORT;
 		if (sk->sk_protocol != IPPROTO_UDP) {
-			printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
+			pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
 			       tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
 			goto err;
 		}
@@ -1368,7 +1556,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	case L2TP_ENCAPTYPE_IP:
 		err = -EPROTONOSUPPORT;
 		if (sk->sk_protocol != IPPROTO_L2TP) {
-			printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
+			pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
 			       tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
 			goto err;
 		}
@@ -1376,7 +1564,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	}
 
 	/* Check if this socket has already been prepped */
-	tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
+	tunnel = l2tp_tunnel(sk);
 	if (tunnel != NULL) {
 		/* This socket has already been prepped */
 		err = -EBUSY;
@@ -1405,12 +1593,37 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	if (cfg != NULL)
 		tunnel->debug = cfg->debug;
 
+#if IS_ENABLED(CONFIG_IPV6)
+	if (sk->sk_family == PF_INET6) {
+		struct ipv6_pinfo *np = inet6_sk(sk);
+
+		if (ipv6_addr_v4mapped(&np->saddr) &&
+		    ipv6_addr_v4mapped(&sk->sk_v6_daddr)) {
+			struct inet_sock *inet = inet_sk(sk);
+
+			tunnel->v4mapped = true;
+			inet->inet_saddr = np->saddr.s6_addr32[3];
+			inet->inet_rcv_saddr = sk->sk_v6_rcv_saddr.s6_addr32[3];
+			inet->inet_daddr = sk->sk_v6_daddr.s6_addr32[3];
+		} else {
+			tunnel->v4mapped = false;
+		}
+	}
+#endif
+
 	/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
 	tunnel->encap = encap;
 	if (encap == L2TP_ENCAPTYPE_UDP) {
 		/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
 		udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
 		udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
+		udp_sk(sk)->encap_destroy = l2tp_udp_encap_destroy;
+#if IS_ENABLED(CONFIG_IPV6)
+		if (sk->sk_family == PF_INET6 && !tunnel->v4mapped)
+			udpv6_encap_enable();
+		else
+#endif
+		udp_encap_enable();
 	}
 
 	sk->sk_user_data = tunnel;
@@ -1421,20 +1634,25 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	tunnel->old_sk_destruct = sk->sk_destruct;
 	sk->sk_destruct = &l2tp_tunnel_destruct;
 	tunnel->sock = sk;
+	tunnel->fd = fd;
+	lockdep_set_class_and_name(&sk->sk_lock.slock, &l2tp_socket_class, "l2tp_sock");
+
 	sk->sk_allocation = GFP_ATOMIC;
 
+	/* Init delete workqueue struct */
+	INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
+
 	/* Add tunnel to our list */
 	INIT_LIST_HEAD(&tunnel->list);
-	spin_lock_bh(&pn->l2tp_tunnel_list_lock);
-	list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
-	spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
-	synchronize_rcu();
 	atomic_inc(&l2tp_tunnel_count);
 
 	/* Bump the reference count. The tunnel context is deleted
-	 * only when this drops to zero.
+	 * only when this drops to zero. Must be done before list insertion
 	 */
 	l2tp_tunnel_inc_refcount(tunnel);
+	spin_lock_bh(&pn->l2tp_tunnel_list_lock);
+	list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
+	spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
 
 	err = 0;
 err:
@@ -1455,25 +1673,8 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
  */
 int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
 {
-	int err = 0;
-	struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL;
-
-	/* Force the tunnel socket to close. This will eventually
-	 * cause the tunnel to be deleted via the normal socket close
-	 * mechanisms when userspace closes the tunnel socket.
-	 */
-	if (sock != NULL) {
-		err = inet_shutdown(sock, 2);
-
-		/* If the tunnel's socket was created by the kernel,
-		 * close the socket here since the socket was not
-		 * created by userspace.
-		 */
-		if (sock->file == NULL)
-			err = inet_release(sock);
-	}
-
-	return err;
+	l2tp_tunnel_closeall(tunnel);
+	return (false == queue_work(l2tp_wq, &tunnel->del_work));
 }
 EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
 
@@ -1481,66 +1682,73 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
  */
 void l2tp_session_free(struct l2tp_session *session)
 {
-	struct l2tp_tunnel *tunnel;
+	struct l2tp_tunnel *tunnel = session->tunnel;
 
 	BUG_ON(atomic_read(&session->ref_count) != 0);
 
-	tunnel = session->tunnel;
-	if (tunnel != NULL) {
+	if (tunnel) {
 		BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
+		if (session->session_id != 0)
+			atomic_dec(&l2tp_session_count);
+		sock_put(tunnel->sock);
+		session->tunnel = NULL;
+		l2tp_tunnel_dec_refcount(tunnel);
+	}
 
-		/* Delete the session from the hash */
+	kfree(session);
+}
+EXPORT_SYMBOL_GPL(l2tp_session_free);
+
+/* Remove an l2tp session from l2tp_core's hash lists.
+ * Provides a tidyup interface for pseudowire code which can't just route all
+ * shutdown via. l2tp_session_delete and a pseudowire-specific session_close
+ * callback.
+ */
+void __l2tp_session_unhash(struct l2tp_session *session)
+{
+	struct l2tp_tunnel *tunnel = session->tunnel;
+
+	/* Remove the session from core hashes */
+	if (tunnel) {
+		/* Remove from the per-tunnel hash */
 		write_lock_bh(&tunnel->hlist_lock);
 		hlist_del_init(&session->hlist);
 		write_unlock_bh(&tunnel->hlist_lock);
 
-		/* Unlink from the global hash if not L2TPv2 */
+		/* For L2TPv3 we have a per-net hash: remove from there, too */
 		if (tunnel->version != L2TP_HDR_VER_2) {
 			struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
-
 			spin_lock_bh(&pn->l2tp_session_hlist_lock);
 			hlist_del_init_rcu(&session->global_hlist);
 			spin_unlock_bh(&pn->l2tp_session_hlist_lock);
 			synchronize_rcu();
 		}
-
-		if (session->session_id != 0)
-			atomic_dec(&l2tp_session_count);
-
-		sock_put(tunnel->sock);
-
-		/* This will delete the tunnel context if this
-		 * is the last session on the tunnel.
-		 */
-		session->tunnel = NULL;
-		l2tp_tunnel_dec_refcount(tunnel);
 	}
-
-	kfree(session);
-
-	return;
 }
-EXPORT_SYMBOL_GPL(l2tp_session_free);
+EXPORT_SYMBOL_GPL(__l2tp_session_unhash);
 
 /* This function is used by the netlink SESSION_DELETE command and by
    pseudowire modules.
  */
 int l2tp_session_delete(struct l2tp_session *session)
 {
+	if (session->ref)
+		(*session->ref)(session);
+	__l2tp_session_unhash(session);
+	l2tp_session_queue_purge(session);
 	if (session->session_close != NULL)
 		(*session->session_close)(session);
-
+	if (session->deref)
+		(*session->deref)(session);
 	l2tp_session_dec_refcount(session);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(l2tp_session_delete);
 
-
 /* We come here whenever a session's send_seq, cookie_len or
  * l2specific_len parameters are set.
  */
-static void l2tp_session_set_header_len(struct l2tp_session *session, int version)
+void l2tp_session_set_header_len(struct l2tp_session *session, int version)
 {
 	if (version == L2TP_HDR_VER_2) {
 		session->hdr_len = 6;
@@ -1553,6 +1761,7 @@ static void l2tp_session_set_header_len(struct l2tp_session *session, int versio
 	}
 
 }
+EXPORT_SYMBOL_GPL(l2tp_session_set_header_len);
 
 struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
 {
@@ -1565,7 +1774,16 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
 
 		session->session_id = session_id;
 		session->peer_session_id = peer_session_id;
-		session->nr = 1;
+		session->nr = 0;
+		if (tunnel->version == L2TP_HDR_VER_2)
+			session->nr_max = 0xffff;
+		else
+			session->nr_max = 0xffffff;
+		session->nr_window_size = session->nr_max / 2;
+		session->nr_oos_count_max = 4;
+
+		/* Use NR of first received packet */
+		session->reorder_skip = 1;
 
 		sprintf(&session->name[0], "sess %u/%u",
 			tunnel->tunnel_id, session->session_id);
@@ -1626,7 +1844,6 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
 			hlist_add_head_rcu(&session->global_hlist,
 					   l2tp_session_id_hash_2(pn, session_id));
 			spin_unlock_bh(&pn->l2tp_session_hlist_lock);
-			synchronize_rcu();
 		}
 
 		/* Ignore management session in session count value */
@@ -1658,8 +1875,21 @@ static __net_init int l2tp_init_net(struct net *net)
 	return 0;
 }
 
+static __net_exit void l2tp_exit_net(struct net *net)
+{
+	struct l2tp_net *pn = l2tp_pernet(net);
+	struct l2tp_tunnel *tunnel = NULL;
+
+	rcu_read_lock_bh();
+	list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) {
+		(void)l2tp_tunnel_delete(tunnel);
+	}
+	rcu_read_unlock_bh();
+}
+
 static struct pernet_operations l2tp_net_ops = {
 	.init = l2tp_init_net,
+	.exit = l2tp_exit_net,
 	.id   = &l2tp_net_id,
 	.size = sizeof(struct l2tp_net),
 };
@@ -1672,7 +1902,14 @@ static int __init l2tp_init(void)
 	if (rc)
 		goto out;
 
-	printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION);
+	l2tp_wq = alloc_workqueue("l2tp", WQ_UNBOUND, 0);
+	if (!l2tp_wq) {
+		pr_err("alloc_workqueue failed\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
 
 out:
 	return rc;
@@ -1681,6 +1918,10 @@ out:
 static void __exit l2tp_exit(void)
 {
 	unregister_pernet_device(&l2tp_net_ops);
+	if (l2tp_wq) {
+		destroy_workqueue(l2tp_wq);
+		l2tp_wq = NULL;
+	}
 }
 
 module_init(l2tp_init);