if remembered one is not acknowledged, consider
channel broken and resend break request on other channel
+ ===========================================
+
+ - remember sent and not acked oplock break requests
+ in a list (on the smbXsrv_connection or so)
+ - for each such request, start a timer when putting
+ it into the list
+ - develop an arithmetic and a mechanism using the SIOCOUTQ
+ ioctl (checked at every I/O on the interface)
+ to detect when a packet has really left the host.
+ - if the algo says that the packet has been sent,
+ disable timer and remove it from the list.
+ ==> really?
+ what about 'left the host' vs. 'ack has been received'?
+ - if oplock break reply arrives, disable timer and remove
+ pkt from list.
+ - if timer expires, consider channel broken and
+ resend break on other channel
+
+ ===========================================
+
- interface characteristics:
--------------------------