hi list!
i have a problem with ip routing!
first of all my configuration:
Tux1 .... embedded linux (kernel-2.4.10) running busybox-0.60.3
and 2 lan interfaces in different networks
default gateway 10.1.0.254 via eth0
R1, R2 .. router (linux for testing)
Tux2 .... linux with network different to Tux1/eth0/eth1
eth0=10.1.0.1/16 +-----+ eth1=10.2.0.1/16
.--|Tux1 |--.
| +-----+ |
eth1=10.1.0.254/16 | | eth1=10.2.0.254/16
+-----+ +-----+
ip_forward=1 | R1 | | R2 | ip_forward=1
+-----+ +-----+
eth0=10.3.1.254/16 | | eth0=10.3.2.254/16
| |
'-----+-----'
| eth0=10.3.0.1/16
+-----+
|Tux2 |
+-----+
i want to achieve, that each packet received on Tux1/eth1 will also be
replied via this interface. this isn't the case now, because the
received packets came from a different network and therefore the replies
are sent back via Tux1/eth0 using the default route.
but the replies have to be sent even when the connection between
Tux1/et0 and R1 is not available. a possible solution is, setting a
network route for network Tux2/eth0 via Tux1/eth1, but in my special
case, i do not know from which network i'll receive the packets!
and here i reached the point where my knowledge ends;-(
i tried to solve this problem in my application running on Tux1, using
the following code:
s = socket();
bind(s, "10.2.0.1"); // bind to Tux1/eth1
listen(s);
s2 = accept(s);
int yes=1;
setsockopt(s2, SOL_SOCKET, SO_DONTROUTE, &yes, sizeof(yes));
...but setting SO_DONTROUTE on socket s2 doesn't have the effect, that
the reply packets are always sent back via Tux1/eth1!
is it possible at all to guarantee this in any case? because this means
bypassing the routing stuff!
any hints welcome!
greetings,
rainer
-
: send the line "unsubscribe linux-net" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
