[Bug-wget] TCP Fast Open for HTTP

[Hubert Tarasiuk]

Hello Wget developers,

I have prepared TCP Fast Open support for HTTP requests in Wget.

I have prepared sample TCP segment dump to show how it works:
https://github.com/jy987321/Wget/wiki/TCP-TFO

The TFO is disabled by default and can be enabled using --tcp-fast-open
option when running Wget.

The support for TFO has been added only recently to Linux kernel (3.6
for client and 3.7 for server) and is not supported on Winodws AFAIK.
Therefore, it is added as conditional compilation code. In order to
force the use of it, you can pass --enable-tcp-tfo (--disable-tcp-tfo)
to ./configure script. The default is to include the code if possible
(if required constants are defined in <sys/socket.h>).

The support for TFO has been added to Python test suite. In order to
make it work, you need to enable both client-side and server-side TFO
support in your Linux kernel:
$ echo 3 > /proc/sys/net/ipv4/tcp_fastopen

If there is no server-side support, TCP will transparently fall back to
using traditional 3-way handshake.

Please let me know what do you think of this feature. Suggestions or
comments about patches are more than welcome.

The code is available as attachment and on Github.
https://github.com/jy987321/Wget/commits/master-hubert

PS
I was hoping to do some performance tests, but have not found too many
servers that support TFO (actually it is only google.com that I have
found so far).
-- 
Hubert Tarasiuk

0001-Const-qualify-buffer-when-writing-to-fd.patch
Description: Text Data

0002-Some-refactoring-in-request_send.patch
Description: Text Data

0003-Split-request_send-into-request-creation-and-actual-.patch
Description: Text Data

0004-Add-autoconf-test-for-TCP-Fast-Open.patch
Description: Text Data

0005-Add-tcp-fast-open-option.patch
Description: Text Data

0006-Enable-TCP_FASTOPEN-in-testenv-server.patch
Description: Text Data

0007-Support-TCP-Fast-Open-in-connect_to_host-and-connect.patch
Description: Text Data

0008-Pass-pointer-by-value-instead-of-by-reference-to-est.patch
Description: Text Data

0009-Prototype-of-TCP-Fast-Open-support-http.c.patch
Description: Text Data

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