From owner-freebsd-net@freebsd.org Mon Dec 23 10:07:04 2019 Return-Path: Delivered-To: freebsd-net@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 79CA71EB9FA for ; Mon, 23 Dec 2019 10:07:04 +0000 (UTC) (envelope-from vas@sibptus.ru) Received: from admin.sibptus.ru (admin.sibptus.ru [IPv6:2001:19f0:5001:21dc::10]) (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 47hFPz355Fz4T1P for ; Mon, 23 Dec 2019 10:07:03 +0000 (UTC) (envelope-from vas@sibptus.ru) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sibptus.ru; s=20181118; h=In-Reply-To:Message-ID:Subject:To:From:Date; bh=d+mgp4jhvv0NJHHXmJPmIfkKq+Nrqopp4kI6v8I30zM=; b=XNy48Ach4/QiCzjQJL9/IW9igE UsWmSeiigY7mr7zEbRi9wvThT6z/3ZgzuXHzSSG4AZFdfMAPyhVMcoC/zCSHI2pdWp4TMD0/OSLIS roTnUXNH/xl88gzPHpKqDhUjCzNK5iO66MuvEvu6thrpAniNLzb8wz9M4p8K/nLnzpOw=; Received: from vas by admin.sibptus.ru with local (Exim 4.92.3 (FreeBSD)) (envelope-from ) id 1ijKc3-000Awh-Sb; Mon, 23 Dec 2019 17:06:55 +0700 Date: Mon, 23 Dec 2019 17:06:55 +0700 From: Victor Sudakov To: "Andrey V. Elsukov" Cc: freebsd-net@freebsd.org Subject: Re: IPSec transport mode, mtu, fragmentation... Message-ID: <20191223100655.GA41651@admin.sibptus.ru> References: <20191220152314.GA55278@admin.sibptus.ru> <20191220160357.GB56081@admin.sibptus.ru> <20191220162233.GA56815@admin.sibptus.ru> <55eeca4c-9633-339a-f521-b0db462cc1d6@yandex.ru> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bg08WKrSYDhXBjb5" Content-Disposition: inline In-Reply-To: <55eeca4c-9633-339a-f521-b0db462cc1d6@yandex.ru> X-PGP-Key: http://admin.sibptus.ru/~vas/ X-PGP-Fingerprint: 10E3 1171 1273 E007 C2E9 3532 0DA4 F259 9B5E C634 X-Rspamd-Queue-Id: 47hFPz355Fz4T1P X-Spamd-Bar: -------- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=sibptus.ru header.s=20181118 header.b=XNy48Ach; dmarc=pass (policy=none) header.from=sibptus.ru; spf=pass (mx1.freebsd.org: domain of vas@sibptus.ru designates 2001:19f0:5001:21dc::10 as permitted sender) smtp.mailfrom=vas@sibptus.ru X-Spamd-Result: default: False [-8.33 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[sibptus.ru:s=20181118]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+mx]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.20)[multipart/signed,text/plain]; IP_SCORE(-3.23)[ip: (-9.88), ipnet: 2001:19f0:5000::/38(-4.94), asn: 20473(-1.30), country: US(-0.05)]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[sibptus.ru:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[sibptus.ru,none]; SIGNED_PGP(-2.00)[]; FREEMAIL_TO(0.00)[yandex.ru]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:20473, ipnet:2001:19f0:5000::/38, country:US]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Dec 2019 10:07:04 -0000 --bg08WKrSYDhXBjb5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Andrey V. Elsukov wrote: > On 20.12.2019 19:22, Victor Sudakov wrote: > >> What's the root of the problem? ESP packets cannot get fragmented or > >> what?=20 > >=20 > > Wireshark has shown that the "Don't Fragment" flag is set on all ESP > > (protocol 50) packets. Who does this, why, and how can I switch it off > > globally? >=20 > Hi, >=20 > I think this DF flag is originally from TCP packet. You are probably right. I did not think of this. > ESP xform for transport mode just replaces protocol in IP header and > adds some info to the end of a packet. It is rather easy to verify your theory. If you are right, then disabling net.inet.tcp.path_mtu_discovery globally should remove the DF flags from the ESP packets too, right? Of course, net.inet.tcp.path_mtu_discovery=3D0 is not a solution, it's just a way to check the origin of the DF flag. And if you are right, what does it mean to us? Did you see https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D242744 already ? My ultimate wish is to make transport mode work out of the box, without any workarounds like additional host routes or firewall rules. --=20 Victor Sudakov, VAS4-RIPE, VAS47-RIPN 2:5005/49@fidonet http://vas.tomsk.ru/ --bg08WKrSYDhXBjb5 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJeAJG/AAoJEA2k8lmbXsY09eIH/1ks80UCQRMabR9sMOtovodu w+dk0HSX+sknioThIl6LllJdZ7a1EloHnIgWL1nltVUjMJtDU2cON8A+q5g+BEn7 BIxSX/giuELv2PdXrqOT6dZf2WCD+mPbMLTapXo2J2tXzvtuje4eDOvqkfgoTHtP 5TZrvsfoDJjviIzlJl08Gw3D5NWxxfNIVdL5adboaKNI54UYkvSJp2kpxCYKHb1G sM7OCf6F6BJHYrwzrSjVprKycNJTyWU4xSia4LJoujks28uXYhtWfjI+lJbOVJLv 00bzQKJjL19ga1ysLBkHUz5ToVWcGQKLBIilsd5+JlGFbVBCKaUGZ1/n68wO9lM= =BFmJ -----END PGP SIGNATURE----- --bg08WKrSYDhXBjb5--