From nobody Mon May 1 14:08:18 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 4Q94nB1qlyz48Zcx for ; Mon, 1 May 2023 14:08:30 +0000 (UTC) (envelope-from arnaud.houdelette@normandie-univ.fr) Received: from usmtp1.unr-runn.fr (usmtp1.unr-runn.fr [IPv6:2001:660:7404:810::56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4Q94n76yfhz3NJ3 for ; Mon, 1 May 2023 14:08:27 +0000 (UTC) (envelope-from arnaud.houdelette@normandie-univ.fr) Authentication-Results: mx1.freebsd.org; dkim=pass header.d=normandie-univ.fr header.s=20181002 header.b=RLWTDdN4; spf=pass (mx1.freebsd.org: domain of arnaud.houdelette@normandie-univ.fr designates 2001:660:7404:810::56 as permitted sender) smtp.mailfrom=arnaud.houdelette@normandie-univ.fr; dmarc=none DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=normandie-univ.fr; s=20181002; h=In-Reply-To:From:References:To:Subject: MIME-Version:Date:Message-ID:Content-Type:Sender:Reply-To:Cc: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=euUmD1ecmTz8iw1z5NjhGRej198QFYPRMk7Ct8tUmCU=; b=RLWTDdN4XcKvXghHyO3WM7EL+ KmagbZUtj2K2GqntocX5Hhx5Ryk4DWylz3Uhan+0LXuv8kevs5QxSNuuz+p8PetauuarazvPsH1JF IjURAw6C0SI9SgUmsBazE9o1A+tYP9QteRWx86S5uXl1lkAnBCRnxRM2JdfGCi8h+iwgnmphhMS8H ezh7obbb6oXolFoZfb0+DGtAVy9WGeN5B8QHBl91gunJF9oMXPOg3yPhVLlciesdlfrV8Qd6lQ6nY me0Kzn+PRSVDgSIBoObP/ZASCFifSAjLgqfhR+yo7wSVEyHYIjg2HnGoaGozMFFlV6SwApjL/Agoe e6rJ4H6Zw==; Received: from [2a01:e0a:3e0:9910:a136:53a9:aa92:da84] by usmtp1.unr-runn.fr with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1ptUCQ-000AOU-LU for freebsd-net@freebsd.org; Mon, 01 May 2023 16:08:18 +0200 Content-Type: multipart/alternative; boundary="------------9qTfYlcROkBJX1PkA3bbUEh3" Message-ID: Date: Mon, 1 May 2023 16:08:18 +0200 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 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: Duplicates IP packets when using CARP and ECMP routes. To: freebsd-net@freebsd.org References: <3f3507f6-fc53-444b-8730-d61143ba3c1e@app.fastmail.com> Content-Language: fr-FR From: Arnaud Houdelette-Langlois In-Reply-To: <3f3507f6-fc53-444b-8730-d61143ba3c1e@app.fastmail.com> X-Spamd-Result: default: False [-3.50 / 15.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-0.999]; R_SPF_ALLOW(-0.20)[+ip6:2001:660:7404:810::/64]; R_DKIM_ALLOW(-0.20)[normandie-univ.fr:s=20181002]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; DKIM_TRACE(0.00)[normandie-univ.fr:+]; MLMMJ_DEST(0.00)[freebsd-net@freebsd.org]; MIME_TRACE(0.00)[0:+,1:+,2:~]; FROM_EQ_ENVFROM(0.00)[]; ASN(0.00)[asn:2200, ipnet:2001:660::/32, country:FR]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; DMARC_NA(0.00)[normandie-univ.fr]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_HAS_DN(0.00)[]; TO_DN_NONE(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_TLS_ALL(0.00)[] X-Rspamd-Queue-Id: 4Q94n76yfhz3NJ3 X-Spamd-Bar: --- X-ThisMailContainsUnwantedMimeParts: N This is a multi-part message in MIME format. --------------9qTfYlcROkBJX1PkA3bbUEh3 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Thanks for the info. I opened the PR : https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=271168 Arnaud Houdelette-Langlois Administrateur des infrastructures systèmes et réseaux Normandie Université +33 2 31 56 69 54 Le 29/04/2023 à 23:44, Alexander Chernikov a écrit : > > > On Sat, 29 Apr 2023, at 11:01 AM, Arnaud Houdelette-Langlois wrote: >> >> Hi. >> >> We got a freebsd router with both ospf/bpg and multipath routes >> (ECMP) (using the new bird2 with netlink) . >> >> The router got an interface with carp enabled on it (gateway for >> admin vlan). >> >> Packets received on the carp address gets routed 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’s not a known problem. > Please do open the PR with details. >> -- >> Arnaud Houdelette-Langlois >> Administrateur des infrastructures systèmes et réseaux >> Normandie Université >> +33 2 31 56 69 54 >> > > /Alexander --------------9qTfYlcROkBJX1PkA3bbUEh3 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit

Thanks for the info.

I opened the PR : https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=271168


Arnaud Houdelette-Langlois
Administrateur des infrastructures systèmes et réseaux
Normandie Université
+33 2 31 56 69 54
Le 29/04/2023 à 23:44, Alexander Chernikov a écrit :


On Sat, 29 Apr 2023, at 11:01 AM, Arnaud Houdelette-Langlois wrote:

Hi.

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

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

Packets received on the carp address gets routed 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’s not a known problem. 
Please do open the PR with details.
-- 
Arnaud Houdelette-Langlois
Administrateur des infrastructures systèmes et réseaux
Normandie Université
+33 2 31 56 69 54


/Alexander
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