From: Sowmini Varadhan <sowmini.varad...@oracle.com> Date: Wed, 18 Jul 2018 03:33:40 -0700
> On (07/18/18 15:19), Ka-Cheong Poon wrote: >> >bind() and connect() are using the sa_family/ss_family to have >> >the application signal to the kernel about whether ipv4 or ipv6 is >> >desired. (and bind and connect are doing the right thing for >> >v4mapped, so that doesnt seem to be a problem there) >> > >> >In this case you want the application to signal that info via >> >the optlen. (And the reason for this inconsistency is that you dont >> >want to deal with the user->kernel copy in the same way?) >> >> >> Because doing that can break existing RDS apps. Existing code >> does not check the address family in processing this socket >> option. It only cares about the address and port. If the new > > I'll leave this up to DaveM. Existing code only handles IPv4, > > everywhere else, we always check the sa_family or ss_family > first and verify the length afterward. This was DaveM's original > point about bind/connect/sendmsg. I dont know why rds sockopts have > to be special. Yes, but the above point is valid. If the code never verified the sa_family value before, it is a very real possibility that code exists out that which is not initializing it or setting it incorrectly. Those apps have worked for a long time, and suddenly will break. We often have to deal with unfortunate mistakes like this. But for now, I guess the check can be added but we have to look out for any regressions this causes and revert if necessary. Thanks.
