From nobody Sat Apr 29 21:44:02 2023 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 4Q83095HGRz48JFB for ; Sat, 29 Apr 2023 21:44:25 +0000 (UTC) (envelope-from melifaro@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 "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Q83094pfLz3rHX for ; Sat, 29 Apr 2023 21:44:25 +0000 (UTC) (envelope-from melifaro@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1682804665; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=GKhZh428R7f75ar1HDT6eIpObFDQCK0TU6fLOiW2MKc=; b=MDsJI4n1PNBM4tMFsHhLBSaFsLR4b97qqUy1jt21T8849rWww4AHMDJhY7bVsr/j/Rt57s 72uW0XIBG9G1jeLGR2RyiSq+g7nKXCdGlhV0wD7+QCI2Qp//uTZh0SxqC4uEo/WdLErZC2 cnDk3vwOoiE+wGUuebmFBsTHN+PFEjh1rURhBDW8WlRtEno+Ze8pehhXGUHdSKgY9MYul0 gnqBH20FljZK+t7IySpd/IAeabZHbGoJd0QVqh1VuriC/RTeG8SwOB6G/mY1/GeOLCuyEn xJjiRCdbE5C4IUfCXOdBR4kiAjvEEmVoLfe9pEzgsHYtiSMmepNLFBm4RXSSSg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1682804665; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=GKhZh428R7f75ar1HDT6eIpObFDQCK0TU6fLOiW2MKc=; b=Rc7Wf2L2BWkelI+a52E8M/l5IaNRMAKagEJvmit3wLVG9AfaGYixWetgrBcRiwisYh2lvY joIv6VJs+CXM7YiZtD9kBUR3AbRw2UvzrnTKoxU84zBUg8aefxknOZ0288gc4XP7zTvM/9 R6axhjalu8SWn4U4hJoLC9SQZRjgpkFjfOoYuC6vSMbz4D1/6pXfimkJ5TTfxdH6xEILlA DHzpPFhPNqptBtXJnXjKDx4V35HDIB7B6Yv3Ahuu6HL1xsOfgpvHZJkDDwGwdG9mYRJ0i1 YDkoXuV6ojmIATqiYbdsk5rhSsSlzdkR+6+ZNw+9B6HN+LAVidwkHidG9x+Rvw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1682804665; a=rsa-sha256; cv=none; b=bYyF4xiUpPEqoECOpSheGeNzhyjW5Cbaqf/tpctRsoAOnJV5RzsfZFhRUlpscoM3ppNZ1F oIyoYf3H0R81gg6ZscreAu74tGUFNBTgzKctob7U9b2Pt18qIZY4xWQERegxu/MSJtkh7z wXg5pTCHPZwbkj3rZSn8lGEx1FuxzK5H6KfQvAeuCe7c6h/f+2dAQBHH1/OeRmxvUAgTHa FDVSsAfFacJBNcIs11RhMB8/elW+n2HqJEHIdHNrC8Mpp6w9tBWou50UOmva1IHH4kSXNp bp7srFy93jLTm6AmWUOZ7V+MAs68fIs2qiJZ7bqyH/iZKfUrlPMSE3daOH/+Bw== Received: from auth2-smtp.messagingengine.com (auth2-smtp.messagingengine.com [66.111.4.228]) (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) (Authenticated sender: melifaro/mail) by smtp.freebsd.org (Postfix) with ESMTPSA id 4Q83093hdZzy5M for ; Sat, 29 Apr 2023 21:44:25 +0000 (UTC) (envelope-from melifaro@FreeBSD.org) Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailauth.nyi.internal (Postfix) with ESMTP id A0BD527C0054 for ; Sat, 29 Apr 2023 17:44:23 -0400 (EDT) Received: from imap43 ([10.202.2.93]) by compute4.internal (MEProxy); Sat, 29 Apr 2023 17:44:23 -0400 X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvhedrfedvudcutefuodetggdotefrodftvfcurf hrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecuuegr ihhlohhuthemuceftddtnecunecujfgurhepofgfggfkjghffffhvffutgesrgdtreerre erjeenucfhrhhomhepfdetlhgvgigrnhguvghrucevhhgvrhhnihhkohhvfdcuoehmvghl ihhfrghroheshfhrvggvuefuffdrohhrgheqnecuggftrfgrthhtvghrnhepjeetjefgie eliedtgedvvdeuffdukefhhfduleejheduvdefgeehvedtudfgueeknecuvehluhhsthgv rhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepmhgvodhmvghsmhhtphgruh hthhhpvghrshhonhgrlhhithihqddufedvledvuddvfedvqddvleefiedutdegkedqmhgv lhhifhgrrhhopeephfhrvggvuefuffdrohhrghesmhhplhhsrdhivg X-ME-Proxy: Feedback-ID: i02494642:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 685862D4007D; Sat, 29 Apr 2023 17:44:23 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.9.0-alpha0-374-g72c94f7a42-fm-20230417.001-g72c94f7a 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 Message-Id: <3f3507f6-fc53-444b-8730-d61143ba3c1e@app.fastmail.com> In-Reply-To: References: Date: Sat, 29 Apr 2023 22:44:02 +0100 From: "Alexander Chernikov" To: freebsd-net@freebsd.org Subject: Re: Duplicates IP packets when using CARP and ECMP routes. Content-Type: multipart/alternative; boundary=80913dd4434a4406b2ac92c3ea60565d X-ThisMailContainsUnwantedMimeParts: N --80913dd4434a4406b2ac92c3ea60565d Content-Type: text/plain;charset=utf-8 Content-Transfer-Encoding: quoted-printable On Sat, 29 Apr 2023, at 11:01 AM, Arnaud Houdelette-Langlois wrote: > Hi. >=20 > We got a freebsd router with both ospf/bpg and multipath routes (ECMP)= (using the new bird2 with netlink) . >=20 > The router got an interface with carp enabled on it (gateway for admin= vlan). >=20 > Packets received on the carp address gets routed on all known routes t= owards destination. Thus, the destination host receives duplicates ip pa= ckets. (which disrupts most udp based protocols) >=20 > Using a simple alias instead of carp solve the problem. Is this a know= n problem, or should I fill a PR ? >=20 No, that=E2=80=99s not a known problem.=20 Please do open the PR with details. > --=20 > Arnaud Houdelette-Langlois > Administrateur des infrastructures syst=C3=A8mes et r=C3=A9seaux > Normandie Universit=C3=A9 > +33 2 31 56 69 54 >=20 /Alexander --80913dd4434a4406b2ac92c3ea60565d Content-Type: text/html;charset=utf-8 Content-Transfer-Encoding: quoted-printable

=
On Sat, 29 Apr 2023, at 11:01 AM, Arnaud Houdelette-Langl= ois wrote:

Hi= .

We got a freebsd router with both ospf/bpg and multipath rou= tes (ECMP) (using the new bird2 with netlink) .

The router g= ot an interface with carp enabled on it (gateway for admin vlan).

Packets received on the carp address gets r= outed on all known routes towards destination. Thus, the destination host receives duplicates ip packets. (which disrupts most udp based protocols)

Using a simple alias instead of carp solve the problem. Is this= a known problem, or should I fill a PR ?

No= , that=E2=80=99s not a known problem. 
Please do open= the PR with details.
--=20
Arnaud Houdelette-Langlois
Administrateur des infrastructures syst=C3=A8mes et r=C3=A9seaux
Normandie Universit=C3=A9
+33 2 31 56 69 54

<= br>
/Alexander
--80913dd4434a4406b2ac92c3ea60565d--