From owner-freebsd-hackers@freebsd.org Mon Jun 22 13:54:38 2020 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 50C7134C9B7; Mon, 22 Jun 2020 13:54:38 +0000 (UTC) (envelope-from hrs@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49r9rZ1PRvz4qXB; Mon, 22 Jun 2020 13:54:38 +0000 (UTC) (envelope-from hrs@FreeBSD.org) Received: from localhost (unknown [IPv6:2400:4051:a743:3c00:16:ceff:fe34:2700]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) (Authenticated sender: hrs) by smtp.freebsd.org (Postfix) with ESMTPSA id 3214633254; Mon, 22 Jun 2020 13:54:37 +0000 (UTC) (envelope-from hrs@FreeBSD.org) Date: Mon, 22 Jun 2020 22:40:15 +0900 (JST) Message-Id: <20200622.224015.2228079563921213662.hrs@FreeBSD.org> To: melifaro@ipfw.ru Cc: current@freebsd.org, net@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: net.inet6.ip6.deembed_scopeid removal From: Hiroki Sato In-Reply-To: <645741592773762@mail.yandex.ru> References: <626011592740709@mail.yandex.ru> <645741592773762@mail.yandex.ru> X-Old-PGPkey-fingerprint: BDB3 443F A5DD B3D0 A530 FFD7 4F2C D3D8 2793 CF2D X-PGPkey-fingerprint: 6C0D 2353 27CF 80C7 901E FDD2 DBB0 7DC6 6F1F 737F X-Mailer: Mew version 6.8 on Emacs 26.3 Mime-Version: 1.0 Content-Type: Multipart/Signed; protocol="application/pgp-signature"; micalg=pgp-sha512; boundary="--Security_Multipart(Mon_Jun_22_22_40_15_2020_216)--" Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Jun 2020 13:54:38 -0000 ----Security_Multipart(Mon_Jun_22_22_40_15_2020_216)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit "Alexander V. Chernikov" wrote in <645741592773762@mail.yandex.ru>: me> [re-sending email with as non-html] me> me> Hey, me> me> I would like to deprecate net.inet6.ip6.deembed_scopeid sysctl while me> leaving the current default behaviour. me> me> This sysctl controls whether IPv6 scope is embedded in the IPv6 me> address or not when reading or writing route/interface/ifaddr data via me> rtsock/sysctl. me> me> Embedding scope in the address is a hack, that overwrites some of the me> bits that can be used otherwise. It was probably implemented that way me> to simplify route table interactions, as rtable uses this hack to add me> link-local addresses to the same radix tree. me> me> The change to fix the userland api by filling in sin6_scopeid and me> avoid touching IPv6 address was added in r243187, 7 years ago. It me> provided the sysctl in question, allowing to preserve compatibility me> with older applications, by reverting to the old behavior. me> me> 7 years looks like enough timeframe for the applications to be me> adjusted. Unless any major objections arise, I'm going to remove the me> code and make de-embedded IPv6 addresses the only option on July 5 me> 2020. I agree that it is time to remove it and I do not think we need to wait more. This knob was for debugging purpose rather than for keeping compatibility. A concern was that recovering the scopeid might have performance penalty. -- Hiroki ----Security_Multipart(Mon_Jun_22_22_40_15_2020_216)-- Content-Type: application/pgp-signature Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iMkEABMKAC4WIQRsDSNTJ8+Ax5Ae/dLbsH3Gbx9zfwUCXvC0vxAcaHJzQGZyZWVi c2Qub3JnAAoJENuwfcZvH3N/07gCCJDGMuuj3AcZoIfHbf+yrdGL/8Ox3/gnMw/C m3giiNCVHDSvWOgz/6/V+Tk0bOYuLcL95Y6V59sOIEojejYfm24fAgkBr48RfN4Z 8cTc1TGkjupVEebByICBQV4nAQYMj6naQd+A5nxOwZEfDsqpouqQmxLCVu/O5b2u rygd5E9CTMlJQPw= =suQy -----END PGP SIGNATURE----- ----Security_Multipart(Mon_Jun_22_22_40_15_2020_216)----