[tproxy] connection go to CLOSE_WAIT after sending FIN

[Jan Engelhardt]

>>>My client opens a transparent connection to the server, sends a message
>>>and then closes the connection with FIN. The server replies with an 
>>>ACK, WITHOUT sending a FIN.
>>>Now I see that the connection stays in the ip_conntrack table in 
>>>CLOSE_WAIT state. During that time I can not reuse the connection. 
>>>(SYNs to the same dest are not sent).
>>
>>This is correct, as per RFC 793 page 21 and page 39.
>>
>>>1) Isn't the correct behavior for that connection is to go to 
>>>FIN_WAIT_2 state? Is it a bug?
>>>2) The CLOSE_WAIT timeout is 500 seconds. Is there a way I can still 
>>>open a new connection to the same destination?
>>
>>setsockopt SO_REUSEADDR may help.
>
>As far as I understand, the RFC 793 states that the correct behavior is
>to go to state FIN_WAIT_2. 
>We go to CLOSE_WAIT only if we receive FIN and send ACK. 
>Page 21:
>CLOSE-WAIT - represents waiting for a connection termination request
>		from the LOCAL user.
>FIN-WAIT-2 - represents waiting for a connection termination request
>    from the REMOTE TCP.

If the client sends a FIN (optionally with ACK), the server responds with ACK
and goes into CLOSE-WAIT. The client goes to FIN-WAIT-2. The server may
continue to send data.


	-`J'
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