netdev - Re: How to compile tcp fast open client app with kernel tfo client support ?

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Date:	Fri, 9 Nov 2012 13:53:42 -0500
From:	Yuchung Cheng <ycheng@...gle.com>
To:	Vincent Li <vincent.mc.li@...il.com>
Cc:	Vijay Subramanian <subramanian.vijay@...il.com>,
	netdev@...r.kernel.org
Subject: Re: How to compile tcp fast open client app with kernel tfo client
 support ?

On Fri, Nov 9, 2012 at 1:47 PM, Vincent Li <vincent.mc.li@...il.com> wrote:
> On Fri, Nov 9, 2012 at 10:23 AM, Vijay Subramanian
> <subramanian.vijay@...il.com> wrote:
>>> htmlgettfo.c: In function 'get_page_thread':
>>> htmlgettfo.c:109: error: 'MSG_FASTOPEN' undeclared (first use in this function)
>>> htmlgettfo.c:109: error: (Each undeclared identifier is reported only once
>>> htmlgettfo.c:109: error: for each function it appears in.)
>>>
>>> I have the 3.6.0 kernel header file package installed
>>> /usr/src/linux-headers-3.6.0-custom, the user space include file
>>> /usr/include/linux is original one coming with 10.0.4 distro kernel
>>>
>>> I am suspecting I don't have proper linux header file that has
>>> MSG_FASTOPEN declared in user space. can anyone shed a light on how to
>>> get MSG_FASTOPEN supported and compiled in client code properly?
>>>
>>
>> Vincent ,
>> You can try adding the following to the client code.
>>
>> #define MSG_FASTOPEN    0x20000000
>>
>> This is missing still from user space header files I presume.
>>
>> Vijay
>
> Thanks Vijay, that did it. and the load banlancer doesn't recognize
> the option, but traffic pass through ok. the data is sent through the
> final ack of 3WHS from linux.
Hi Vincent,

Note that MSG_FASTOPEN flag should be used only once. Subsequent
sendto(MSG_FASTOPEN) == connect() on connected sockets. You can verify
if the fast open is successful by checking a bit in TCP_INFO.
http://patchwork.o zlabs.org/patch/192883/ if you are running a fresh
netdev build.

I'll submit a patch to update the man page on MSG_FASTOPEN too.

Yuchung


>
> Vincent
> --
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