From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [PATCHv2 net-next] sctp: add support for SCTP_REUSE_PORT sockopt Date: Thu, 14 Jun 2018 07:49:45 -0400 Message-ID: <20180614114945.GC6733@hmswarspite.think-freely.org> References: <26fda4cd22604d88a68a58c2b007231984e5f4f0.1528947888.git.lucien.xin@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: network dev , linux-sctp@vger.kernel.org, Marcelo Ricardo Leitner , Michael Tuexen , davem@davemloft.net To: Xin Long Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:59360 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754885AbeFNLuW (ORCPT ); Thu, 14 Jun 2018 07:50:22 -0400 Content-Disposition: inline In-Reply-To: <26fda4cd22604d88a68a58c2b007231984e5f4f0.1528947888.git.lucien.xin@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Jun 14, 2018 at 11:44:48AM +0800, Xin Long wrote: > This feature is actually already supported by sk->sk_reuse which can be > set by socket level opt SO_REUSEADDR. But it's not working exactly as > RFC6458 demands in section 8.1.27, like: > > - This option only supports one-to-one style SCTP sockets > - This socket option must not be used after calling bind() > or sctp_bindx(). > > Besides, SCTP_REUSE_PORT sockopt should be provided for user's programs. > Otherwise, the programs with SCTP_REUSE_PORT from other systems will not > work in linux. > > To separate it from the socket level version, this patch adds 'reuse' in > sctp_sock and it works pretty much as sk->sk_reuse, but with some extra > setup limitations that are needed when it is being enabled. > > "It should be noted that the behavior of the socket-level socket option > to reuse ports and/or addresses for SCTP sockets is unspecified", so it > leaves SO_REUSEADDR as is for the compatibility. > > Note that the name SCTP_REUSE_PORT is kind of confusing, it is identical > to SO_REUSEADDR with some extra restriction, so here it uses 'reuse' in > sctp_sock instead of 'reuseport'. As for sk->sk_reuseport support for > SCTP, it will be added in another patch. > > Thanks to Neil to make this clear. > > v1->v2: > - add sctp_sk->reuse to separate it from the socket level version. > Thanks Xin, Assuming some documentation for man sctp(7) is in the works Acked-by: Neil Horman