Hi again. Problem is - fib_validate_source() explicitly doesn't allow any local address to be specified as source address. I figured out I'm not the first in need for different behavior. One of the solutions I've found is forward_shared patch [http://www.ssi.bg/~ja/forward_shared-2.6.25-2.diff] which exists for centuries. Actually, it is not working for me but it is addressing the same thing - forwarding packets with local addresses. I've solved my problem (Cisco's GRE keepalive and Linux) with this small change: --- linux-2.6.26.3/net/ipv4/fib_frontend.c-orig 2008-09-16 01:50:07.000000000 +0200 +++ linux-2.6.26.3/net/ipv4/fib_frontend.c 2008-09-16 01:50:27.000000000 +0200 @@ -260,7 +260,7 @@ int fib_validate_source(__be32 src, __be net = dev_net(dev); if (fib_lookup(net, &fl, &res)) goto last_resort; - if (res.type != RTN_UNICAST) + if ((res.type != RTN_UNICAST) && !((res.type == RTN_LOCAL) && (dev->type == ARPHRD_IPGRE))) { goto e_inval_res; *spec_dst = FIB_RES_PREFSRC(res); fib_combine_itag(itag, &res); ---------------------------------------------------------------------- I'm pretty sure this is not the right solution, if there is a need for 'solution' at all. Maybe this behavior is what we need and there is no real need to ever forward packets coming with local source address. I failed to find a way to test if destination address is remote end of GRE tunnel. I found another strange (for me, at least) thing - ip_route_input_slow() is discarding packets if "IP is not enabled" on the device. The only way to "enable IP" on IP_GRE interface is to assign it an IP. Is there another way of "enabling IP" on IP_GRE interface? I think there is no much need for assigning an IP address to GRE interface. Am I wrong here? IP should be 'enabled' by default for IP_GRE interfaces. PS. Of course, I order this forwarding of encapsulated packets with local source address to work, GRE tunnel must be created, GRE interface have to be UP with IP address assigned and with forwarding enabled. Sincerely, Bosko -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
