Messages in this thread | | | From | Veeriah Vijay-A19819 <> | Subject | PROBLEM: TCP keepalive probe count | Date | Wed, 15 Oct 2003 16:15:57 -0500 |
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I am using 2.4.7 kernel and seem to have a problem where my TCP connection aborts when both the client and the server are, perfectly fine, up and running and sending data to each other.
I was able to reproduce this problem by doing the following. I setup the tcp parameters to be as follows : tcp_keepalive_time = 2 tcp_keepalive_probes = 1 tcp_keepalive_intvl = 3 My server and client send data to each other every 2 seconds.
From tcpdump output I figured out the following. After a keepalive_probe is sent out (at the expiry of keepalive_time) if it is immediately followed by some valid data, then the ack for the keepalive_probe from the remote side does not seem to reset the probes_out to 0. Because of this when the keepalive_timer expires the next time it RSTs the connection. The following code in tcp_input.c, seems to be the problem if ((prior_packets = tp->packets_out) == 0) goto no_queue; .... return 1;
no_queue: tp->probes_out = 0 ....
Since in my case prior_packets is not 0, because of the valid data, probes_out is not being reset. Can somebody let me know if I am missing something here or is it a genuine problem that has been fixed in a later release.
Thanks, Vijay
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