Connection timeouts not effective on blocking write of DIMSE

[gunterze]

Configured Network Connection Extension attributes:

Name	Type	Description (LDAP Attribute)
Send Timeout	integer	Timeout in ms for sending other DIMSE RQs than C-STORE RQs; no timeout if absent (dcmSendTimeout)
Store Timeout	integer	Timeout in ms for sending C-STORE RQs; no timeout if absent (dcmStoreTimeout)
Response Timeout	integer	Timeout in ms for receive of other outstanding DIMSE RSPs than C-MOVE or C-GET RSPs; no timeout if absent (dcmResponseTimeout)
Idle Timeout	integer	Indicates aborting of idle Associations after specified timeout in ms; no timeout if absent (dcmIdleTimeout)

not effective, if the peer DICOM Application stops reading from the TCP channel, so writing blocks after 2x of configured

Name	Type	Description (LDAP Attribute)
TCP Send Buffer Size	integer	TCP send buffer size; use system defaults if absent (dcmTCPSendBufferSize)

bytes are written to the socket and so also writing the A-ABORT PDU, triggered on expiration of a configured timeout, get blocked.

Solution:
Block writing the A-ABORT PDU a finite time configurable by new Network Connection Extension attribute:

Name	Type	Description (LDAP Attribute)
A-ABORT Timeout	integer	Timeout in ms for waiting for finishing sending any DIMSE before sending an A-ABORT PDU, triggered by the application or by expiration of a configured other timeout of this Connection. If the timeout expires, the TCP connection will be closed without sending the A-ABORT PDU before. (dcmAATimeout)

Apply the same timeout also for writing A-RELEASE RP, to also prevents blocking in the (unlikely) case of a DICOM peer application stopping DIMSE reading, but sending an A-RELEASE RQ.

Writing A-RELEASE RQ are still blocked by writing DIMSE messages, now even preventing to interrupt emission of P-DATA-PDUs for one DIMSE by a A-RELEASE RQ.