[lwip-devel] [bug #34517] persist timer is started although there is unacked data

[Simon Goldschmidt]

Update of bug #34517 (project lwip):

                  Status:                    None => In Progress            
             Assigned to:                    None => goldsimon              
         Planned Release:                         => 1.4.1                  

    _______________________________________________________

Follow-up Comment #3:

Having had another look at this, I think that our condition when to start the
persist timer is somewhat insecure. TCP/IP Illustrated (and other sources) say
the persist timer should be started when we receive a zero-window
announcement. However, we start it when we have more data to send than the
window allows.

This can lead to starting the persist timer when we have much data to send and
the remote host is simply disconnected. I think this is insecure since the
persist timer prevents connection timeout and we should only use standard
retransmission in the case of having too much data to send without receiving a
zero window.

This would mean starting the persist timer would be done in tcp_receive when
processing an ACK / window update (same place where it is stopped when the
window grows > 0) instead of starting it in tcp_output when we have more data
to send than the window allows.

    _______________________________________________________

Reply to this item at:

  <http://savannah.nongnu.org/bugs/?34517>

_______________________________________________
  Nachricht geschickt von/durch Savannah
  http://savannah.nongnu.org/