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net/inet/inet_close.c: Still fussing with f3ab9abe51. Re-analyze all disconnection events, update comments, removed one of two non-standard return values. A failure is returned only in cases where the socket was not actually closed.

This commit is contained in:
Gregory Nutt 2019-09-25 08:16:37 -06:00
parent 8e079d73d9
commit 0b9416a40c
1 changed files with 21 additions and 17 deletions
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38
net/inet/inet_close.c
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@ -122,32 +122,36 @@ static uint16_t tcp_close_eventhandler(FAR struct net_driver_s *dev,
if ((flags & TCP_DISCONN_EVENTS) != 0)
{
/* The disconnection is complete. Wake up the waiting thread with an
* appropriate result:
* appropriate result. Success is returned in these cases:
*
* * TCP_CLOSE indicates normal successful closure. TCP_ABORT is less
* likely but still means that the socket was closed, albeit
* abnormally. We will call either a success.
* * TCP_CLOSE indicates normal successful closure. The TCP_CLOSE
* event is sent when the remote ACKs the outgoing FIN in the
* FIN_WAIT_1 state. That is the appropriate time for the
* application to close the socket.
*
* NOTE: The underlying connection, however, will persist, waiting
* for the FIN to be returned by the remote in the TIME_WAIT state.
*
* * TCP_ABORT is less likely but still means that the socket was
* closed, albeit abnormally due to a RST from the remote.
*
* * TCP_TIMEDOUT would be reported in this context if there is no
* ACK response to the FIN in the FIN_WAIT_2 state. The socket will
* again be closed abnormally.
*
* This is the only true error case.
*
* * NETDEV_DOWN would indicate that the network went down before the
* close completed. TCP_TIMEDOUT is not expected in this context.
* Non-standard return values are used to indicate these anomalous
* cases.
*
* NOTE: In the TCP_CLOSE case, the event is sent when the remote
* ACKs then outgoing FIN in the FIN_WAIT_1 state. That is the
* appropriate time for the application to close the socket. The
* underlying connection, however, will persist, waiting for the FIN
* to be returned by the remote in the TIME_WAIT state.
* close completed. A non-standard ENODEV error will be returned
* in this case. The socket will be left in a limbo state if the
* network is taken down but should recover later when the
* NETWORK_DOWN event is processed further.
*/
if ((flags & NETDEV_DOWN) != 0)
{
pstate->cl_result = -ENODEV;
}
else if ((flags & TCP_TIMEDOUT) != 0)
{
pstate->cl_result = -ETIMEDOUT;
}
else
{
pstate->cl_result = OK;