michi: 1. Is that to create two sockets and one bind to 10.0.0.1 the other bind to 10.0.0.2 then use epoll wait these two sockets ? 2. Is there any way to find out the turple like TCP then the UDP server can reply with exactly the ip it recieved the client's request ? Thanks. 2011/10/15 <michi1@michaelblizek.twilightparadox.com>:
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