• Fabrice Bellet's avatar
    conncheck: adjust recheck on timeout strategy · d516fca1
    Fabrice Bellet authored
    The pair recheck on timeout can easily cause repetitive rechecks in
    a ping-pong effect, if both peers with the same behaviour try to
    check the same pair almost simultaneously, and if the network rtt
    is greater than the initial timer rto. The reply to the initial
    stun request may arrive after the in-progress conncheck
    cancellation (described in RFC 5245, sect 7.2.1.4). Cancellation
    creates a new stun request, and forgets the initial one.
    The conncheck timer is restarted with the same initial value,
    so the same situation happens again later.
    
    We choose to avoid resetting the timer in such situation. After enough
    retransmissions, the timeout delay, that doubles after each timeout,
    becomes longer than the rtt, and the stun reply can be handled.
    
    Differential Revision: https://phabricator.freedesktop.org/D1115
    d516fca1
conncheck.c 151 KB