[Bug manual/1983] socket(s, 1) said to discard sent data

[Bug manual/1983] socket(s, 1) said to discard sent data

[a.herefishyfishies at yahoo dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=1983

herefishy <a.herefishyfishies at yahoo dot com> changed:

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                 CC|                            |a.herefishyfishies at yahoo
                   |                            |dot com

--- Comment #3 from herefishy <a.herefishyfishies at yahoo dot com> 2012-08-28 22:17:09 UTC ---
I am not so sure the manual is wrong, especially for a remote socket vs. on on
the LAN. 

Please refer to my bug report, with sample client and server code.  By actual
test it demonstrates that, at least for data sizes around 4K bytes, data is
lost unless the connection is deliberately held open by a sleep(1) before
close(socket). This was the case for Linux/CentOS but not Solaris, and was MUCH
more prone to happen on a remote host but not as often (very rarely) on the
local LAN. 

http://sourceware.org/bugzilla/show_bug.cgi?id=14500

Examples and statistics are included with the above linked bug report.

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[Bug manual/1983] socket(s, 1) said to discard sent data

[neleai at seznam dot cz]

https://sourceware.org/bugzilla/show_bug.cgi?id=1983

--- Comment #4 from Ondrej Bilka <neleai at seznam dot cz> ---
*** Bug 11489 has been marked as a duplicate of this bug. ***

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[Bug manual/1983] socket(s, 1) said to discard sent data

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=1983

Florian Weimer <fweimer at redhat dot com> changed:

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[Bug manual/1983] socket(s, 1) said to discard sent data

[bpeeluk at yahoo dot co dot uk]

------- Additional Comments From bpeeluk at yahoo dot co dot uk  2007-10-16 16:53 -------
Created an attachment (id=2045)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=2045&action=view)
Program to help demonstrate that the documentation is wrong


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http://sourceware.org/bugzilla/show_bug.cgi?id=1983

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[Bug manual/1983] socket(s, 1) said to discard sent data

[bpeeluk at yahoo dot co dot uk]

------- Additional Comments From bpeeluk at yahoo dot co dot uk  2007-10-16 16:48 -------
I've just wasted a fair amount of coding time after being mislead by this bug so
I'm just commenting in the hope that it will encourage someone to change it.

You can demonstrate that it doesn't discard the pending send data with the
attached program. The program opens a connection to the given web server, sleeps
for 5 seconds, then calls shutdown. If you disconnect your network cable or set
up a firewall within those five seconds, you can see with tcpdump that the OS
still tries to send the data even though shutdown was called.

# Establish connection

17:42:39.081415 IP 192.168.1.201.1708 > 209.132.176.174.80: S
4039457085:4039457085(0) win 5840 <mss 1460,sackOK,timestamp 385240294
0,nop,wscale 3>
17:42:39.268932 IP 209.132.176.174.80 > 192.168.1.201.1708: S
810590603:810590603(0) ack 4039457086 win 5792 <mss 1418,sackOK,timestamp
3715979507 385240294,nop,wscale 4>
17:42:39.268970 IP 192.168.1.201.1708 > 209.132.176.174.80: . ack 1 win 730
<nop,nop,timestamp 385240341 3715979507>

# Sleep for five seconds, network cable is pulled out in this time

# Now you can see that the client is still trying to send the data, even though
shutdown has been called and the program is no longer running.

17:42:44.271789 IP 192.168.1.201.1708 > 209.132.176.174.80: P 1:1025(1024) ack 1
win 730 <nop,nop,timestamp 385241592 3715979507>
17:42:44.272235 IP 192.168.1.201.1708 > 209.132.176.174.80: F 1025:1025(0) ack 1
win 730 <nop,nop,timestamp 385241592 3715979507>
17:42:45.219521 IP 192.168.1.201.1708 > 209.132.176.174.80: P 1:1025(1024) ack 1
win 730 <nop,nop,timestamp 385241829 3715979507>
17:42:47.115725 IP 192.168.1.201.1708 > 209.132.176.174.80: P 1:1025(1024) ack 1
win 730 <nop,nop,timestamp 385242303 3715979507>
17:42:50.908161 IP 192.168.1.201.1708 > 209.132.176.174.80: P 1:1025(1024) ack 1
win 730 <nop,nop,timestamp 385243251 3715979507>
17:42:58.493019 IP 192.168.1.201.1708 > 209.132.176.174.80: P 1:1025(1024) ack 1
win 730 <nop,nop,timestamp 385245147 3715979507>
17:43:13.662722 IP 192.168.1.201.1708 > 209.132.176.174.80: P 1:1025(1024) ack 1
win 730 <nop,nop,timestamp 385248939 3715979507>
17:43:44.002164 IP 192.168.1.201.1708 > 209.132.176.174.80: P 1:1025(1024) ack 1
win 730 <nop,nop,timestamp 385256523 3715979507>


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http://sourceware.org/bugzilla/show_bug.cgi?id=1983

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