From nobody Sat Dec 28 02:08:59 2024 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 4YKm4v3Qmgz5jk7g for ; Sat, 28 Dec 2024 02:09:03 +0000 (UTC) (envelope-from paul@redbarn.org) Received: from util.redbarn.org (util.redbarn.org [24.104.150.222]) (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 "*.redbarn.org", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4YKm4t2WJGz4JBK for ; Sat, 28 Dec 2024 02:09:02 +0000 (UTC) (envelope-from paul@redbarn.org) Authentication-Results: mx1.freebsd.org; dkim=fail ("headers rsa verify failed") header.d=redbarn.org header.s=util header.b=bPBFnehD; spf=pass (mx1.freebsd.org: domain of paul@redbarn.org designates 24.104.150.222 as permitted sender) smtp.mailfrom=paul@redbarn.org; dmarc=pass (policy=reject) header.from=redbarn.org Received: from family.redbarn.org (family.redbarn.org [24.104.150.213]) (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 "*.redbarn.org", Issuer "RapidSSL TLS RSA CA G1" (not verified)) by util.redbarn.org (Postfix) with ESMTPS id B5B35160C24 for ; Sat, 28 Dec 2024 02:08:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=redbarn.org; s=util; t=1735351739; bh=LlTxsE4fviawd2MK0MvZp+/LqGawOHFbi7FCmCjVRFc=; h=From:To:Subject:Date:In-Reply-To:References; b=bPBFnehDM6mK0zpXaUAjd2iwKqAR6+MlNw3IR3S57Z9RFH+iEK2MktIIkbOBU8tF5 hsp1BvlDcvX7YdaSUBfu7g8i24ig+wBhg8JauKIIeBoohkIcqnc+1VE20EHxeGVKfr XcbfI3JWhJXV6pyyR7MbEQg4/osrynYv70SSvooY= Received: from dhcp-151.access.rits.tisf.net (dhcp-151.access.rits.tisf.net [24.104.150.151]) (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 did not present a certificate) by family.redbarn.org (Postfix) with ESMTPSA id 84EB9C3F22; Sat, 28 Dec 2024 02:08:59 +0000 (UTC) From: Paul Vixie To: freebsd-net@freebsd.org Subject: Re: per-FIB socket binding Date: Sat, 28 Dec 2024 02:08:59 +0000 Message-ID: <2751272.KRxA6XjA2N@dhcp-151.access.rits.tisf.net> Organization: FW In-Reply-To: References: <4p5o59s4-5p70-0775-1479-990o1s5po7r2@yvfgf.mnoonqbm.arg> 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 Content-Type: multipart/alternative; boundary="nextPart3377114.VqM8IeB0Os" Content-Transfer-Encoding: 7Bit X-Spamd-Result: default: False [-3.70 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-1.000]; NEURAL_HAM_LONG(-1.00)[-1.000]; CTE_CASE(0.50)[]; DMARC_POLICY_ALLOW_WITH_FAILURES(-0.50)[]; RCVD_IN_DNSWL_MED(-0.40)[24.104.150.222:from,24.104.150.213:received]; R_SPF_ALLOW(-0.20)[+ip4:24.104.150.0/24]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[redbarn.org:-]; DMARC_POLICY_ALLOW(0.00)[redbarn.org,reject]; R_DKIM_REJECT(0.00)[redbarn.org:s=util]; ARC_NA(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; FROM_HAS_DN(0.00)[]; FREEFALL_USER(0.00)[paul]; HAS_ORG_HEADER(0.00)[]; TO_DN_NONE(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; MISSING_XM_UA(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-net@freebsd.org]; RCVD_VIA_SMTP_AUTH(0.00)[]; MLMMJ_DEST(0.00)[freebsd-net@freebsd.org]; ASN(0.00)[asn:33651, ipnet:24.104.150.0/24, country:US]; MIME_TRACE(0.00)[0:+,1:+,2:~] X-Rspamd-Queue-Id: 4YKm4t2WJGz4JBK X-Spamd-Bar: --- This is a multi-part message in MIME format. --nextPart3377114.VqM8IeB0Os Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="iso-8859-1" > On 21.12.2024 19:34, Bjoern A. Zeeb wrote: > > How much use are FIBs still these days? Half of the original use cases > > I can think of could easily and better be overcome by using vnet jails > > with a physical or virtual interface (e.g, vcc) being delegated to the > > vnet. Among the other half is simple multihoming. If a host has interfaces on two networks then it needs two default routes which means two FIBs. Many of us use ipfw to select a FIB for an outbound packet based on its IP source address. Without this the next-next- hop will wonder why we're failing BCP38 source address validation, and it may be a firewall which only passes traffic it expects, and it may be a differently congested network that upsets TCP pacing since the payloads take one path and the ACKs take the other. Path symmetry is an unalloyed good. Path assymetry is a livable problem but worthy of avoidance. Some operators just avoid multi-homing. As an operator I often don't have a choice about multi-homing or else my other choices are worse. FIBs make all of this better, and easily. > > I would honestly know who and how FIBs are still in use today or if they > > should be put on a list to be removed for 16 (I assume I might be > > surprised). I have a refactor to propose for the networking stack in 16 but more for performance and clarity than for correctness or simplicity. More on that another day. In any case I use FIBs everywhere all the time. On Monday, December 23, 2024 10:29:01 AM UTC Andrey V. Elsukov wrote: > Some might say that VNET is useless and should be removed instead. We > have bhyve and old-style jails. Without VNET the kernel code will be > robust and simple again, and easy for debugging. I introduced Mr. Zec to NL-Net when he was first looking for sponsors, and I was very happy with the results, and even more so when the FreeBSD Foundation got involved and more so after that when Mr. Zeeb got involved. I think VNET has earned a place in FreeBSD's pantheon but that the form it takes in the source code (all those macros) could be simplified. > FIBs are useful as is, but also can be used with "ipfw setfib" that make > it irreplaceable. For my primary FIB use case, ipfw is OK, but I think we need a different default. To that end, see Message-ID <38589000.XM6RcZxFsP@dhcp-151.access.rits.tisf.net>. -- Paul Vixie --nextPart3377114.VqM8IeB0Os Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="iso-8859-1"

> On 21.12.2024 19:34, Bjoern A. Ze= eb wrote:

>= ; > How much use are FIBs still these days?=A0 Half of the original use = cases

>= ; > I can think of could easily and better be overcome by using vnet jai= ls

>= ; > with a physical or virtual interface (e.g, vcc) being delegated to t= he

>= ; > vnet.


Among the other half is simple multihoming. If a host has interfaces on = two networks then it needs two default routes which means two FIBs. Many of= us use ipfw to select a FIB for an outbound packet based on its IP source = address. Without this the next-next-hop will wonder why we're failing BCP38= source address validation, and it may be a firewall which only passes traf= fic it expects, and it may be a differently congested network that upsets T= CP pacing since the payloads take one path and the ACKs take the other. Pat= h symmetry is an unalloyed good. Path assymetry is a livable problem but wo= rthy of avoidance. Some operators just avoid multi-homing. As an operator I= often don't have a choice about multi-homing or else my other choices are = worse. FIBs make all of this better, and easily.


> > I would honestly know who and how FIBs are still in use today = or if they

>= ; > should be put on a list to be removed for 16 (I assume I might be

>= ; > surprised).


I have a refactor to propose for the networking stack in 16 but more for= performance and clarity than for correctness or simplicity. More on that a= nother day. In any case I use FIBs everywhere all the time.


On Monday, December 23, 2024 10:29:01 AM UTC Andrey V. Elsukov wrote:

>= ; Some might say that VNET is useless and should be removed instead. We

>= ; have bhyve and old-style jails. Without VNET the kernel code will be

>= ; robust and simple again, and easy for debugging.


I introduced Mr. Zec to NL-Net when he was first looking for sponsors, a= nd I was very happy with the results, and even more so when the FreeBSD Fou= ndation got involved and more so after that when Mr. Zeeb got involved. I t= hink VNET has earned a place in FreeBSD's pantheon but that the form it tak= es in the source code (all those macros) could be simplified.


> FIBs are useful as is, but also can be used with "ipfw setfib&= quot; that make

>= ; it irreplaceable.


For my primary FIB use case, ipfw is OK, but I think we need a different= default. To that end, see Message-ID <38589000.XM6RcZxFsP@dhcp-151.acce= ss.rits.tisf.net>.


--

Pau= l Vixie

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