From nobody Wed Jul 06 22:37:52 2022 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 6C22C87BAF5 for ; Wed, 6 Jul 2022 22:38:06 +0000 (UTC) (envelope-from ggm@algebras.org) Received: from mail-lj1-x230.google.com (mail-lj1-x230.google.com [IPv6:2a00:1450:4864:20::230]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4LdZF91Psxz4gbC for ; Wed, 6 Jul 2022 22:38:05 +0000 (UTC) (envelope-from ggm@algebras.org) Received: by mail-lj1-x230.google.com with SMTP id q8so7702296ljj.10 for ; Wed, 06 Jul 2022 15:38:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=algebras-org.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yZ/RKkTiOSqXGjXWKIBsetwrq3p9dJr/bG+CpmoEm2Q=; b=ZiA9rp5MtrvJVu1iou6LaJv0hDvYJFEnspWtFrEOetfikHNtzmGkDPG0f3RoCcB3u5 t6rgZh6pheUoLe4uPqDdbKGi+ZW4Tm9O6dyFUgpgELkUo4GbIPDwDk1EyYguO3Hrw+B2 +PzUEloFQbaL4+Axw1YOb7yzO/yrAe5XV7dTnLmZu/gSF49AZ9CltbhALyktOJTvNjCp yc9chUM8utFHU2Zd+ScxgXfYlqW1cHlkTQZOqlxW5XJoFurX0Pj8anQgw7X+UsJmEchu 75I5D5BOJS7dAlGynhYmn6UUwAOs9YBsCBB764fVsinwKOLXq4vpuC1Hc2t7o10ZNJOx aw8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yZ/RKkTiOSqXGjXWKIBsetwrq3p9dJr/bG+CpmoEm2Q=; b=oi8JPIecI22WU3sXuOvTmEkAn7beFpTnM/DEvmpeI/pIMfvVnqNgpjJJxNIjIkPmEG 23GBA1eBO/5JaYHBPASjKCVDwPjoABrdu6e2t22SyzJkCJwBLgixmB93Qk1XC4DKeoWY EBGt5fhCmfhr8XrN8eddGYnCMYJUGPYUbQtySoR8IbvIz3XS9yp/iRFyuJ3CCXBopfRF oC6ix7e7M5xfKhJOCdsvhACRQF0E8eprlmDHJhGwzSSgqOd7jFa7otDPEWpx0PhDrLZT EO9bFZ7by0ByOvcGam8QVtMG75Pf+6K6p4UOvboDposcYARbnZ5kYtQO3WB+TGiymDWi 6Rmg== X-Gm-Message-State: AJIora/q4xm9m9uKiZwfA2RYNDswJa3emnG9zEHtUhn4Zzkhral4kYju Ayl/jMUiPvUk6VtdgHESiLap3d3m/FAiXSusJQDYWwDskKc= X-Google-Smtp-Source: AGRyM1sHf1uA/ROb+bDEpEYsl9hgbLSyblo6/ATjVRuEqF1f8kDf97NpSDvEuvJyEbHzKFbgy4v4NhNcfTqV6C0isb4= X-Received: by 2002:a2e:b5d1:0:b0:25a:9f46:6791 with SMTP id g17-20020a2eb5d1000000b0025a9f466791mr23434210ljn.465.1657147083841; Wed, 06 Jul 2022 15:38:03 -0700 (PDT) List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 References: <202207062206.266M6UVV033854@mail.karels.net> In-Reply-To: <202207062206.266M6UVV033854@mail.karels.net> From: George Michaelson Date: Thu, 7 Jul 2022 08:37:52 +1000 Message-ID: Subject: Re: experimental support for IPv4 unicast extensions To: mike@karels.net Cc: freebsd-net@freebsd.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4LdZF91Psxz4gbC X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=algebras-org.20210112.gappssmtp.com header.s=20210112 header.b=ZiA9rp5M; dmarc=none; spf=pass (mx1.freebsd.org: domain of ggm@algebras.org designates 2a00:1450:4864:20::230 as permitted sender) smtp.mailfrom=ggm@algebras.org X-Spamd-Result: default: False [-3.50 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[algebras-org.20210112.gappssmtp.com:s=20210112]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-net@freebsd.org]; TO_DN_NONE(0.00)[]; DMARC_NA(0.00)[algebras.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[algebras-org.20210112.gappssmtp.com:+]; RCPT_COUNT_TWO(0.00)[2]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::230:from]; NEURAL_HAM_SHORT(-1.00)[-1.000]; MLMMJ_DEST(0.00)[freebsd-net]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] X-ThisMailContainsUnwantedMimeParts: N In my opinion, these changes are definitely worth accepting. Removing barriers to deployment of 240/4 is a good thing. The changes are really simple, easy to understand and gated by sysctl which is sensible. I really hope we can move from 'default off' to 'default on' in a reasonably short period of time. Disclaimer: I work in a regional registry so I am probably biassed. While I might personally prefer people move to v6, I think this is a good body of code change to deploy. Coincidentally I was a co-author on an expired draft to un-reserve 240/4 many years ago, but it (foolishly perhaps) proposed private use, not global unicast. The kernel changes would however have been much the same. Thanks for doing this Mike. -George On Thu, Jul 7, 2022 at 8:07 AM Mike Karels wrote: > > I have been corresponding with the authors of Internet-Drafts that relax > restrictions on parts of the IPv4 address space to allow normal unicast > use, and I have FreeBSD changes to allow experimentation with these > updates. This message summarizes my changes, and solicits input. > > The changes are all controlled by sysctl, and default to "off". > The parts of the address space in question and the relevant changes: > > 0/8 (network 0) [1]: Restrictions on network 0 are lifted if the sysctl > net.inet.ip.allow_zeronet is set to 1. This applies to packet forwarding > and ICMP echo. > > 224/4 (Experimental/"Class E") [2]: Restrictions on the Experimental > address class are lifted if the sysctl net.inet.ip.allow_experimental > is set to 1. This applies to packet forwarding and ICMP echo. > > 127/8 (loopback net) [3]: The size of the reservation for the loopback > network can be reduced from 127/8 to 127.0/16 using the sysctl > net.int.ip.loopback_mask. My current sysctl sets the mask, but that > is a little cumbersome; I should probably change the sysctl to allow > a mask length to be set. This change is limited to the kernel; the > IN_LOOPBACK macro uses the current mask in the kernel, but the default > mask at user level. Also, some user programs use IN_LOOPBACKNET along > with a Class A shift to crack this by hand. The kernel change affects > IP packet input and output as well as forwarding. > > The changes described above are all included in a single review for now, > although I would probably separate them before pushing them. (They > necessarily collide though.) The review is intended for comments only, > and is https://reviews.freebsd.org/D35741. I think it makes sense to > put these changes in -current in order to enable experimentation, but > I wanted to open the subject for discussion first. > > Changes are also being made in Linux, although I don't know their state. > > Note that there is a related proposal and change to allow use of the > lowest host on a network/subnet [4]. This change was essentially a bug > fix for FreeBSD, and is already in -current and 13.1-RELEASE. > > Mike > > [1] https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-0/01/ > > [2] https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-240/ > > [3] https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-127/ > > [4] https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-lowest-address/ >