Hello,
I have written a script using IO::Socket::INET to read and write data
to modbus devices.
This is running on OSX V 10.4.11
I have the latest IO::Socket Library from CPAN.
Using perl 5.8.6 from OSX and I built perl 5.10 which has the same issue
The script will work for a few loops, maybe doing 100 or so modbus
read/writes
Then the sockets are closed for no apparent reason.
I did a tcpdump, what seams to be happening is that when an error
occurs in the TCP packet, the OSX end gets stuck in a loop requesting
and re requesting the packet.
Until eventually the other end sends RST and force-ably closes the
socket.
Then everything goes bad, if I just close the problem socket then one
by one the other sockets close.
(This is confirmed with IO::Select)
When I get this block I have to close all sockets and reopen them to
clear it.
I copied the same script to another OSX machine running 10.4.11 and I
have the exact same problem.
I copied the script to a machine running Mandrivia 2009 and it works
just fine!
Any Ideas what might be going on ?
TCPDUMP (192.168.251.3 is the OSX machine)
10:17:19.508241 IP 192.168.251.3.52312 > 192.168.251.102.502: P
160:172(12) ack 90 win 65535 <nop,nop,timestamp 1360281049 65303>
10:17:19.514522 IP 192.168.251.102.502 > 192.168.251.3.52312: P 90:101
(11) ack 172 win 5669 <timestamp 65461 1360281049,nop,nop>
10:17:19.514544 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281049 65461>
That was a request and reply acknowledged - Normal
10:17:19.747871 IP 192.168.251.3.52312 > 192.168.251.102.502: P
172:187(15) ack 101 win 65535 <nop,nop,timestamp 1360281049 65461>
Request
10:17:19.752164 IP 192.168.251.102.502 > 192.168.251.3.52312: P
101:113(12) ack 187 win 5654 <timestamp 163 1360281049,nop,nop>
Reply
10:17:19.752183 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281050 65461>
Rejected
10:17:20.501290 IP 192.168.251.102.502 > 192.168.251.3.52312: P
101:113(12) ack 187 win 5654 <timestamp 912 1360281050,nop,nop>
Resent
10:17:20.501355 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281051 65461>
Rejected
10:17:20.750835 IP 192.168.251.3.52312 > 192.168.251.102.502: P
172:187(15) ack 101 win 65535 <nop,nop,timestamp 1360281051 65461>
Resend request (even though it was acknowledged) Is that legal ??
10:17:20.762936 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 1174 1360281051,nop,nop>
Accept
10:17:21.929985 IP 192.168.251.102.502 > 192.168.251.3.52312: P
101:113(12) ack 187 win 5654 <timestamp 2341 1360281051,nop,nop>
Reply Again
10:17:21.930046 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281054 65461>
Rejected
10:17:21.931308 IP 192.168.251.102.502 > 192.168.251.3.52312: P
101:113(12) ack 187 win 5654 <timestamp 2342 1360281054,nop,nop>
Resent
10:17:21.931324 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281054 65461>
Rejected
10:17:21.932624 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 2343 1360281054,nop,nop>
?
And so on
10:17:22.751058 IP 192.168.251.3.52312 > 192.168.251.102.502: P
172:187(15) ack 101 win 65535 <nop,nop,timestamp 1360281055 65461>
10:17:22.759845 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 3171 1360281055,nop,nop>
10:17:24.778286 IP 192.168.251.102.502 > 192.168.251.3.52312: P
101:113(12) ack 187 win 5654 <timestamp 5189 1360281055,nop,nop>
10:17:24.778318 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281060 65461>
10:17:24.779660 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 5190 1360281060,nop,nop>
10:17:26.751479 IP 192.168.251.3.52312 > 192.168.251.102.502: P
172:187(15) ack 101 win 65535 <nop,nop,timestamp 1360281063 65461>
10:17:26.758087 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 7169 1360281063,nop,nop>
10:17:30.470519 IP 192.168.251.102.502 > 192.168.251.3.52312: P
101:113(12) ack 187 win 5654 <timestamp 10881 1360281063,nop,nop>
10:17:30.470583 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281071 65461>
10:17:30.471828 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 10882 1360281071,nop,nop>
10:17:34.752192 IP 192.168.251.3.52312 > 192.168.251.102.502: P
172:187(15) ack 101 win 65535 <nop,nop,timestamp 1360281079 65461>
10:17:34.754071 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 15164 1360281079,nop,nop>
10:17:37.576828 IP 192.168.251.102.502 > 192.168.251.3.52312: P
101:113(12) ack 187 win 5654 <timestamp 17987 1360281079,nop,nop>
10:17:37.576875 IP 192.168.251.3.52312 > 192.168.251.102.502: . ack
101 win 65535 <nop,nop,timestamp 1360281085 65461>
10:17:37.578139 IP 192.168.251.102.502 > 192.168.251.3.52312: . ack
187 win 5654 <timestamp 17988 1360281085,nop,nop>
10:17:50.754009 IP 192.168.251.3.52312 > 192.168.251.102.502: P
172:187(15) ack 101 win 65535 <nop,nop,timestamp 1360281111 65461>
10:17:50.761068 IP 192.168.251.102.502 > 192.168.251.3.52312: R
249188453:249188453(0) win 0
Now I thing 192.168.251.102 gets fed up and boots us off
TIA
Stuart.
