[ECOS] RedBoot sends continuous ACKS in TIME_WAIT state.
Grant Edwards
grante@visi.com
Tue Mar 27 06:03:00 GMT 2001
On Mon, Mar 26, 2001 at 07:49:32PM -0600, Grant Edwards wrote:
> 1 0.000000 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [SYN] Seq=3272446793 Ack=0 Win=32120 Len=0
> 2 0.000795 10.0.0.5 10.0.0.2 TCP 9000 > 1511 [SYN, ACK] Seq=0 Ack=3272446794 Win=1460 Len=0
> 3 0.000878 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [ACK] Seq=3272446794 Ack=1 Win=32120 Len=0
> 4 0.011692 10.0.0.5 10.0.0.2 TCP 9000 > 1511 [PSH, ACK] Seq=1 Ack=3272446794 Win=1460 Len=10
> 5 0.011763 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [ACK] Seq=3272446794 Ack=11 Win=32120 Len=0
> 6 2.285735 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [PSH, ACK] Seq=3272446794 Ack=11 Win=32120 Len=6
> 7 2.286991 10.0.0.5 10.0.0.2 TCP 9000 > 1511 [ACK] Seq=11 Ack=3272446800 Win=1460 Len=0
> 8 3.303892 10.0.0.5 10.0.0.2 TCP 9000 > 1511 [FIN, ACK] Seq=11 Ack=3272446800 Win=1460 Len=0
> 9 3.303974 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [ACK] Seq=3272446800 Ack=12 Win=32120 Len=0
> 10 3.304184 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [FIN, ACK] Seq=3272446800 Ack=12 Win=32120 Len=0
>
> Linux should be in the LAST_ACK state, and isn't supposed to
> send anything in response to the next ACK.
>
> 11 3.318369 10.0.0.5 10.0.0.2 TCP 9000 > 1511 [ACK] Seq=11 Ack=3272446801 Win=1460 Len=0
> 12 3.318424 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [ACK] Seq=3272446801 Ack=12 Win=32120 Len=0
> 13 3.319083 10.0.0.5 10.0.0.2 TCP 9000 > 1511 [ACK] Seq=11 Ack=3272446801 Win=1460 Len=0
> 14 3.319116 10.0.0.2 10.0.0.5 TCP 1511 > 9000 [ACK] Seq=3272446801 Ack=12 Win=32120 Len=0
> 15 3.319754 10.0.0.5 10.0.0.2 TCP 9000 > 1511 [ACK] Seq=11 Ack=3272446801 Win=1460 Len=0
Based on comparisons to the same sequence of events when an
eCos server-app does an active close, the problem appears to be
that the sequence number in the ACKs sent by RedBoot in frames
11, 13, 15 should be 12 instead of 11. One of the states in
the active close sequence isn't advancing the local sequence
number when it receives an ACK. I'm not sure which one should
be doing it.
--
Grant Edwards
grante@visi.com
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