From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowmini Varadhan Subject: Re: [PATCH net-next 2/3] rds: Enable RDS IPv6 support Date: Tue, 26 Jun 2018 09:08:44 -0400 Message-ID: <20180626130844.GD20575@oracle.com> References: <7f4f460079d3d78a18f7d759488048798e99c4db.1529922794.git.ka-cheong.poon@oracle.com> <20180625170317.GA28578@oracle.com> <25e1afda-7497-7f08-815a-286cf775bc09@oracle.com> <20180625175006.GI14823@oracle.com> <43b790c2-8da6-9f18-ae23-ca55388e8b26@oracle.com> <20180626101657.GA20575@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 aserp2120.oracle.com ([141.146.126.78]:45994 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933478AbeFZNIz (ORCPT ); Tue, 26 Jun 2018 09:08:55 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On (06/26/18 21:02), Ka-Cheong Poon wrote: > > In this case, RFC 6724 prefers link local address as source. the keyword is "prefers". > While using non-link local address (say ULA) is not forbidden, > doing this can easily cause inter-operability issues (does the > app really know that the non-link local source and the link > local destination addresses are really on the same link?). I > think it is prudent to disallow this in RDS unless there is a > very clear and important reason to do so. I remember the issues that triggered 6724. The "interop" issue is that when you send from Link-local to global, and need forwarding, it may not work. but I dont think an RDS application today expects to deal with the case that "oh I got back and error when I tried to send to address X on rds socket rs1, let me go and check what I am bound to, and maybe create another socket, and bind it to link-local" You're not doing this for IPv4 and RDS today (you dont have to do this for UDP, afaik) This is especially true if "X" is a hostname that got resovled using DNS > BTW, if it is really > needed, it can be added in future. shrug. You are introducing a new error return. --Sowmini