[net 1/1] tipc: queue socket protocol error messages into socket receive buffer

[net 1/1] tipc: queue socket protocol error messages into socket receive buffer

[Jon Maloy]

From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>

In tipc_sk_filter_rcv(), when we detect protocol messages with error we
call tipc_sk_conn_proto_rcv() and let it reset the connection and notify
the socket by calling sk->sk_state_change().

However, tipc_sk_filter_rcv() may have been called from the function
tipc_backlog_rcv(), in which case the socket lock is held and the socket
already awake. This means that the sk_state_change() call is ignored and
the error notification lost. Now the receive queue will remain empty and
the socket sleeps forever.

In this commit, we convert the protocol message into a connection abort
message and enqueue it into the socket's receive queue. By this addition
to the above state change we cover all conditions.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
---
 net/tipc/socket.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index b6f99b0..49810fd 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1196,6 +1196,7 @@ void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
  * @skb: pointer to message buffer.
  */
 static void tipc_sk_conn_proto_rcv(struct tipc_sock *tsk, struct sk_buff *skb,
+				   struct sk_buff_head *inputq,
 				   struct sk_buff_head *xmitq)
 {
 	struct tipc_msg *hdr = buf_msg(skb);
@@ -1213,7 +1214,16 @@ static void tipc_sk_conn_proto_rcv(struct tipc_sock *tsk, struct sk_buff *skb,
 		tipc_node_remove_conn(sock_net(sk), tsk_peer_node(tsk),
 				      tsk_peer_port(tsk));
 		sk->sk_state_change(sk);
-		goto exit;
+
+		/* State change is ignored if socket already awake,
+		 * - convert msg to abort msg and add to inqueue
+		 */
+		msg_set_user(hdr, TIPC_CRITICAL_IMPORTANCE);
+		msg_set_type(hdr, TIPC_CONN_MSG);
+		msg_set_size(hdr, BASIC_H_SIZE);
+		msg_set_hdr_sz(hdr, BASIC_H_SIZE);
+		__skb_queue_tail(inputq, skb);
+		return;
 	}
 
 	tsk->probe_unacked = false;
@@ -1936,7 +1946,7 @@ static void tipc_sk_proto_rcv(struct sock *sk,
 
 	switch (msg_user(hdr)) {
 	case CONN_MANAGER:
-		tipc_sk_conn_proto_rcv(tsk, skb, xmitq);
+		tipc_sk_conn_proto_rcv(tsk, skb, inputq, xmitq);
 		return;
 	case SOCK_WAKEUP:
 		tipc_dest_del(&tsk->cong_links, msg_orignode(hdr), 0);
-- 
2.1.4

Re: [net 1/1] tipc: queue socket protocol error messages into socket receive buffer

[David Miller]

From: Jon Maloy <jon.maloy@ericsson.com>
Date: Wed, 10 Oct 2018 17:50:23 +0200

> From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
> 
> In tipc_sk_filter_rcv(), when we detect protocol messages with error we
> call tipc_sk_conn_proto_rcv() and let it reset the connection and notify
> the socket by calling sk->sk_state_change().
> 
> However, tipc_sk_filter_rcv() may have been called from the function
> tipc_backlog_rcv(), in which case the socket lock is held and the socket
> already awake. This means that the sk_state_change() call is ignored and
> the error notification lost. Now the receive queue will remain empty and
> the socket sleeps forever.
> 
> In this commit, we convert the protocol message into a connection abort
> message and enqueue it into the socket's receive queue. By this addition
> to the above state change we cover all conditions.
> 
> Acked-by: Ying Xue <ying.xue@windriver.com>
> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>

Applied.