Small correction, the client is using source port as 7801.
-----Original Message-----
From: Guru Chaitanya Perakam
Sent: Monday, July 27, 2015 12:46 PM
To: '[email protected]'
Subject: Ryu manager doesn't send FIN/ACK in response to FIN
Hi,
Issue:
=====
When an Openflow client closes the connection with Ryu Manager by sending a
FIN, only ACK is sent in response.
FIN/ACK is not received by Openflow client. The TCP connection on Ryu Manager
is moved to CLOSE-WAIT state.
This causes our switch (Openflow client) to wait in FIN-WAIT-2 state and then
sends a Reset to Ryu Manager after some timeout.
Again when the switch uses the same source port for reconnection, the
connection fails.
PFA packet dissections text file "ryn-find-issue.txt" with this mail.
Further observations:
=================
Thereafter, if I try to reconnect to Ryu Manager using same source port, the
client is stuck in SYN-SENT state.
The below are the only ways to recover:
1. Killing the Ryu manager sends the pending FIN/ACK messages.
2. Reconnecting to Ryu Manager using different source port.
a. At this state Ryu Manager is sending FIN/ACK for the previous
source port also.
Please resolve this issue, I suspect that TCP connection cleanup is being
performed only when some other activity happens.
Packet capture explanation:
======================
1. RY Manager IP: 10.37.73.180
Port: 6633
2. Switch (Openflow client) IP: 10.37.73.181
Source Port: 7801
Packet 1: Client sends a FIN to Ryu Manager
Packet 2: Ryu Manager sends an ACK
Packet 3: Client sends a RST to forcefully close the connection. (ICMP
destination unreached is received for this message)
Packet 4,5: ICMP destination port unreached messages Packet 6,N: Client keeps
on resending the SYN messages. (Client reuses the same source port 7801 for
reconnection)
Logs on Ryu Manager:
=================
connected socket:<eventlet.greenio.base.GreenSocket object at 0x7f49316759d0>
address:('10.37.73.181', 7801) hello ev <ryu.controller.ofp_event.EventOFPHello
object at 0x7f4931675ad0> move onto config mode EVENT ofp_event->dpset
EventOFPSwitchFeatures switch features ev version: 0x4 msg_type 0x6 xid
0xa85d7a34
OFPSwitchFeatures(auxiliary_id=0,capabilities=79,datapath_id=8398923215522496512,n_buffers=0,n_tables=1)
move onto main mode
EVENT ofp_event->dpset EventOFPStateChange
DPSET: register datapath <ryu.controller.controller.Datapath object at
0x7f4931675a50> EVENT ofp_event->dpset EventOFPStateChange
DPSET: unregister datapath <ryu.controller.controller.Datapath object at
0x7f4931675a50>
Netstat output on Linux where Ryu is installed:
===================================
tcp 0 0 Ubuntu-73.180:6633 10.37.73.181:7801 CLOSE_WAIT
Thanks & regards,
Guru Chaitanya Perakam
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