TCP session teardown time in flows can be made to reflect the real teardown time

[Vedamurthy Joshi]

R2.20 Build 115 Ubuntu 14.04 Juno multinode setup

From VM 219.14.75.4 , i ran hping3 to 219.14.75.3

root@vm2:/home/ubuntu# hping3 -S -p 33000 219.14.75.3 -s 10000 -c 10 -i u1000
HPING 219.14.75.3 (eth0 219.14.75.3): S set, 40 headers + 0 data bytes
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=0 win=0 rtt=2.9 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=1 win=0 rtt=1.8 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=2 win=0 rtt=2.0 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=3 win=0 rtt=2.9 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=4 win=0 rtt=2.0 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=5 win=0 rtt=1.8 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=6 win=0 rtt=1.8 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=7 win=0 rtt=1.7 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=8 win=0 rtt=1.5 ms
len=40 ip=219.14.75.3 ttl=64 DF id=0 sport=33000 flags=RA seq=9 win=0 rtt=1.6 ms

--- 219.14.75.3 hping statistic ---
10 packets transmitted, 10 packets received, 0% packet loss
round-trip min/avg/max = 1.5/2.0/2.9 ms
root@vm2:/home/ubuntu#
====================
So, each TCP session lasted for less than a second.

The flows get created, but the teardown time is shown as empty for these flows until the flow ageout time(180 s here)
After that, the teardown time is updated so that (teardown_time - setup_time) is greater than 180s

Which is not true. Since vrouter can figure out the real teardown time within the flow ageout window, we could reflect that in the flow stats

Attached are the flow stats in this example

[OpenContrail Admin (ci-admin-f)]

bug update...

[Ashok Singh (ashoksr)]

After fix for https://bugs.launchpad.net/juniperopenstack/+bug/1527236, this issue should not be seen, since agent removes Evicted flows during aging instead of waiting for the aging time to complete