Re: [PATCH net-next v20 12/25] ovpn: implement TCP transport

@@ -94,11 +96,23 @@ void ovpn_socket_release(struct ovpn_peer *peer)
 	 * detached before it can be picked by a concurrent reader.
 	 */
 	lock_sock(sock->sock->sk);
-	ovpn_socket_put(peer, sock);
+	released = ovpn_socket_put(peer, sock);
 	release_sock(sock->sock->sk);
 
 	/* align all readers with sk_user_data being NULL */
 	synchronize_rcu();
+
+	/* following cleanup should happen with lock released */
+	if (released) {
+		if (sock->sock->sk->sk_protocol == IPPROTO_UDP) {
+			netdev_put(sock->ovpn->dev, &sock->dev_tracker);
+		} else if (sock->sock->sk->sk_protocol == IPPROTO_TCP) {
+			/* wait for TCP jobs to terminate */
+			ovpn_tcp_socket_wait_finish(sock);
+			ovpn_peer_put(sock->peer);
+		}
+		kfree_rcu(sock, rcu);

+static int ovpn_tcp_parse(struct strparser *strp, struct sk_buff *skb)
+{
+	struct strp_msg *rxm = strp_msg(skb);
+	__be16 blen;
+	u16 len;
+	int err;
+
+	/* when packets are written to the TCP stream, they are prepended with
+	 * two bytes indicating the actual packet size.
+	 * Here we read those two bytes and move the skb data pointer to the
+	 * beginning of the packet

+static void ovpn_tcp_rcv(struct strparser *strp, struct sk_buff *skb)
+{
+	struct ovpn_peer *peer = container_of(strp, struct ovpn_peer, tcp.strp);
+	struct strp_msg *msg = strp_msg(skb);
+	size_t pkt_len = msg->full_len - 2;
+	size_t off = msg->offset + 2;
+	u8 opcode;
+
+	/* ensure skb->data points to the beginning of the openvpn packet */
+	if (!pskb_pull(skb, off)) {

+		net_warn_ratelimited("%s: packet too small for peer %u\n",
+				     netdev_name(peer->ovpn->dev), peer->id);
+		goto err;
+	}

+	/* DATA_V2 packets are handled in kernel, the rest goes to user space */
+	opcode = ovpn_opcode_from_skb(skb, 0);
+	if (unlikely(opcode != OVPN_DATA_V2)) {
+		if (opcode == OVPN_DATA_V1) {
+			net_warn_ratelimited("%s: DATA_V1 detected on the TCP stream\n",
+					     netdev_name(peer->ovpn->dev));
+			goto err;

+err:
+	dev_core_stats_rx_dropped_inc(peer->ovpn->dev);
+	kfree_skb(skb);
+	ovpn_peer_del(peer, OVPN_DEL_PEER_REASON_TRANSPORT_ERROR);
+}
+

+void ovpn_tcp_send_skb(struct ovpn_peer *peer, struct socket *sock,
+		       struct sk_buff *skb)
+{
+	u16 len = skb->len;
+
+	*(__be16 *)__skb_push(skb, sizeof(u16)) = htons(len);
+
+	spin_lock_nested(&sock->sk->sk_lock.slock, OVPN_TCP_DEPTH_NESTING);

+static int ovpn_tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
+{
+	struct ovpn_socket *sock;
+	int ret, linear = PAGE_SIZE;
+	struct ovpn_peer *peer;
+	struct sk_buff *skb;
+
+	lock_sock(sk);
+	rcu_read_lock();
+	sock = rcu_dereference_sk_user_data(sk);
+	if (unlikely(!sock || !sock->peer || !ovpn_peer_hold(sock->peer))) {
+		rcu_read_unlock();
+		release_sock(sk);
+		return -EIO;
+	}
+	rcu_read_unlock();
+	peer = sock->peer;

+
+	if (msg->msg_flags & ~MSG_DONTWAIT) {
+		ret = -EOPNOTSUPP;
+		goto peer_free;
+	}