tipc: don't send gap blocks in ACK messages
In the commit referred to below we eliminated sending of the 'gap' indicator in regular ACK messages, reserving this to explicit NACK ditto. Unfortunately we missed to also eliminate building of the 'gap block' area in ACK messages. This area is meant to report gaps in the received packet sequence following the initial gap, so that lost packets can be retransmitted earlier and received out-of-sequence packets can be released earlier. However, the interpretation of those blocks is dependent on a complete and correct sequence of gaps and acks. Hence, when the initial gap indicator is missing a single gap block will be interpreted as an acknowledgment of all preceding packets. This may lead to packets being released prematurely from the sender's transmit queue, with easily predicatble consequences. We now fix this by not building any gap block area if there is no initial gap to report. Fixes: commit 02288248 ("tipc: eliminate gap indicator from ACK messages") Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Showing
Please register or sign in to comment