From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowmini Varadhan Subject: Re: [PATCH v3 net-next 0/3] rds: IPv6 support Date: Wed, 18 Jul 2018 03:33:40 -0700 Message-ID: <20180718103340.GA3893@oracle.com> References: <20180716162001.GA22404@oracle.com> <954b0239-5d03-997c-d242-cbbd8c0dc8e4@oracle.com> <20180717112720.GA25197@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, santosh.shilimkar@oracle.com, davem@davemloft.net, rds-devel@oss.oracle.com To: Ka-Cheong Poon Return-path: Received: from userp2120.oracle.com ([156.151.31.85]:45788 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726996AbeGRLLF (ORCPT ); Wed, 18 Jul 2018 07:11:05 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: 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. > code suddenly checks that and use it to decide on the address > family, working app will break. As I mentioned before, this > patch set does not change existing behavior. And doing what > you mentioned will change existing behavior and break apps. thank you. --Sowmini