Hello, On Wed, 16 Oct 2013, Hannes Frederic Sowa wrote: > On Wed, Oct 16, 2013 at 10:27:47AM +0300, Julian Anastasov wrote: > > > > I don't know the IPv6 routing but if we find a way > > to keep the desired nexthop in rt6i_gateway and to add > > RTF_GATEWAY checks here and there such solution would be more > > general. FLOWI_FLAG_KNOWN_NH flag can help, if needed. > > I thought about this yesterday but did not see an easy way. How does the IPv4 > implementation accomplish this? In IPv4 rt->rt_flags has no bit to indicate if the route is via gateway (like RTF_GATEWAY in IPv6). We added rt_uses_gateway for this purpose. In the default case, rt_gateway may contain 0 if we return cached result, eg. when target is part of a local subnet. Then IPVS/TEE/RAW can request valid rt_gateway, even with the price of a cloned result, so that rt_gateway can remember the requested nexthop which may differ from daddr. > ipvs caches the dst in its own infrastructure, so we need to be sure we don't > disconnect this dst from the ipv6 routing table, otherwise ip6_dst_check won't > recognize when relookups should be done. Playing games with RTF_GATEWAY seems > dangerous then. dst_check works for IPVS. There is a problem only with the recent changes that moved the indication for PMTU change from dst_check to dst_mtu() calls. But this is safe for IPVS, it handles FRAG_NEEDED for the tunneling mode itself. Initially, I thought IPv6 stores zeroes in rt6i_gateway. But now I see rt6_alloc_cow() to be called for the case I assumed to fail - when no gateway is used. So, I'll try to test the IPVS case in the following 1-2 days and will report after adding some printks. If xt_TEE has the same problem then it should not be IPVS-specific. RAW not tested yet. Regards -- Julian Anastasov <ja@xxxxxx> -- To unsubscribe from this list: send the line "unsubscribe lvs-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
