From mboxrd@z Thu Jan  1 00:00:00 1970
From: michi1@michaelblizek.twilightparadox.com (michi1 at michaelblizek.twilightparadox.com)
Date: Sat, 15 Oct 2011 08:04:44 +0200
Subject: Problem with a UDP server implements
In-Reply-To: <201110150151405785431@gmail.com>
References: <201110150151405785431@gmail.com>
Message-ID: <20111015060444.GA2282@grml>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

Hi!

On 01:51 Sat 15 Oct     , jiangtao.jit wrote:
> Hi:
> 
> I'm writing a UDP server and meet a problem
> the UDP server program is run on a box with single card but has multi ip:
> like    eth0        10.0.0.1
>         eth0:1     10.0.0.2
> 		eth0:2		11.0.0.1
> 
> I bind the server socket with INADDR_ANY
...
> when a client send a request to 10.0.0.1(eth0); the server use 10.0.0.1 to response
> and another client send a request to 10.0.0.2(eth0:1); the server use 10.0.0.2 to response

Well, is seems there is neither a variant of recvfrom() which tells you your
local address nor a variant of sendto() which allows you to specify your local
address. I guess you have to call getaddrinfo() and create a socket for every
address you want to bind to. If you want to stay single threaded you can
switch them to nonblocking and use epoll to wait for packets.

	-Michi
-- 
programing a layer 3+4 network protocol for mesh networks
see http://michaelblizek.twilightparadox.com