On 29/05/2015 00:55, Doug Ledford wrote: > On Thu, 2015-05-28 at 22:05 +0300, Or Gerlitz wrote: >> So what's your concrete saying here? where should we go from here? > > This excerpt is from the commit log of patch 3/12: > > The IB device and port, together with the P_Key and the IP address should > be enough to uniquely identify the ULP net device. > > The problem here is that this is wrong. If we allow more than one > device per pkey with the same GUID, then DHCP breaks, which is bad in > and of itself, but it also breaks ipv6 link local addressing. Which > means that this hunk in patch 4/12: > > +#if IS_ENABLED(CONFIG_IPV6) > + case AF_INET6: > + if (ipv6_chk_addr(net, &addr_in6->sin6_addr, dev, 1)) > + return true; > + > + break; > +#endif > > can now be tricked into returning true for incorrect devices. > > Where do we go from here? > > First, I'm inclined to say we should modify the add_child portion of > IPoIB to refuse to add links to a PKey if that GUID is already present > on that PKey. You could then use different PKeys on the default GUID > for separate namespaces. If you need separate namespaces on the same > PKey, then enable alias GUIDs for use on the local adapter and require > one GUID per namespace on the same PKey. I don't think blocking the current add_child implementation is needed. I agree IPv6 SLAAC and DHCP currently don't work well, and adding alias GUID for child interfaces is important, but the current implementation can be used with static IPv4 addresses, so I don't think it must be disabled.
> Then I'm inclined to say that we should map for namespaces using device, > port, guid/gid, pkey. And in this situation, since a unique guid/gid on > any given pkey maps to a unique dhcp identifier and a unique ipv6 > lladdr, this becomes freely interchangeable with device, port, pkey, > address mappings that this patchset was built around. What if we change the namespaces patches to map (device, port, GID, P_Key, IP) to netdev / namespace? That is, to use both the GID and the IP address. This would allow people to use namespaces with the current implementation (provided they have a valid configuration with no conflicting IP addresses), and once alias GUIDs are added, the GUIDs will be used to uniquely resolve the namespace even with such misconfigurations. Regards, Haggai -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
