socket programming using either eth0 or eth1

Are there any socket programming samples on how to select which ethernet
port (eth0 or eth1) to use for a socket?

David Peters wrote:
> Are there any socket programming samples on how to select which ethernet
> port (eth0 or eth1) to use for a socket?
>

With normal IP traffic, the network interface is selected
based on the routing to the destination.

Do you mean raw sockets?

--

Tauno Voipio
tauno voipio (at) iki fi

Yes. I am working on an app that creates a socket, sends some data, then
closes it. The device I am using has eth0 and possibly eth1. If eth1
exists, I want to use it instead of eth0.

"Tauno Voipio" <(E-Mail Removed)> wrote in message
news:HGOmd.621$(E-Mail Removed)...
> David Peters wrote:
> > Are there any socket programming samples on how to select which ethernet
> > port (eth0 or eth1) to use for a socket?
> >
>
> With normal IP traffic, the network interface is selected
> based on the routing to the destination.
>
> Do you mean raw sockets?
>
> --
>
> Tauno Voipio
> tauno voipio (at) iki fi
>
>

"David Peters" <(E-Mail Removed)> wrote in message
news:419ba344$0$528$(E-Mail Removed)...

> Are there any socket programming samples on how to select which ethernet
> port (eth0 or eth1) to use for a socket?

Are we talking TCP or UDP? Or are we talking some other protocol? And
what do you mean by selecting an ethernet port? Do you mean the packet is
actually sent out that interface? Or do you mean that the source IP address
is the address assigned to that interface?

In short, your post gives us no idea at all what you're trying to do.

DS

David Peters wrote:

> Yes. I am working on an app that creates a socket, sends some data, then
> closes it. The device I am using has eth0 and possibly eth1. If eth1
> exists, I want to use it instead of eth0.

If it's an IP socket you can use a setsockopt(SOL_SOCKET,
SO_BINDTODEVICE, ...) (see "man setsockopt" and "man 7 socket").
If it's a packet socket you look up the interface index with
a SIOCGIFINDEX and bind(2) to that.

Mike

--
Mike Jagdis Web: http://www.eris-associates.co.uk
Eris Associates Limited Tel: +44 7780 608 368
Reading, England Fax: +44 118 926 6974