From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [RFC 0/2] Delayed binding of UDP sockets for Quic per-connection sockets Date: Wed, 31 Oct 2018 22:04:19 -0700 Message-ID: <74393778-62e8-76f5-3bfc-ae280b407278@gmail.com> References: <20181031232635.33750-1-cpaasch@apple.com> <0ce864f0-38b9-59cc-18ea-e071afca347d@gmail.com> <20181101035050.GO80792@MacBook-Pro-19.local> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Ian Swett , Leif Hedstrom , Jana Iyengar To: Christoph Paasch Return-path: Received: from mail-pg1-f196.google.com ([209.85.215.196]:41385 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726208AbeKAOFo (ORCPT ); Thu, 1 Nov 2018 10:05:44 -0400 Received: by mail-pg1-f196.google.com with SMTP id k13so123390pga.8 for ; Wed, 31 Oct 2018 22:04:22 -0700 (PDT) In-Reply-To: <20181101035050.GO80792@MacBook-Pro-19.local> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 10/31/2018 08:50 PM, Christoph Paasch wrote: > What we had here is that we wanted to let a server initiate more than 64K > connections *while* binding also to a source-IP. > With TCP the bind() would then pick a source-port and we ended up hitting the > 64K limit. If we could do an atomic "bind + connect", source-port selection > could ensure that the 4-tuple is unique. > > Or has something changed in recent times that allows to use the 4-tuple > matching when doing this with TCP? Well, yes, although it is not really recent (this came with linux-4.2) You can now bind to an address only, and let the sport being automatically chosen at connect() https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=90c337da1524863838658078ec34241f45d8394d