From nobody Sat Jun 26 19:55:34 2021 X-Original-To: bugs@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 9BA1911E5EF1 for ; Sat, 26 Jun 2021 19:55:34 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (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 "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4GC4Nk3w64z3hks for ; Sat, 26 Jun 2021 19:55:34 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (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 mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 6F0D224B7C for ; Sat, 26 Jun 2021 19:55:34 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 15QJtYGk062744 for ; Sat, 26 Jun 2021 19:55:34 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 15QJtYbZ062743 for bugs@FreeBSD.org; Sat, 26 Jun 2021 19:55:34 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 256850] poor mac address distribution for if_tap Date: Sat, 26 Jun 2021 19:55:34 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 12.2-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: maxim.shalomikhin@kaspersky.com X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter attachments.created Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Bug reports List-Archive: https://lists.freebsd.org/archives/freebsd-bugs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-bugs@freebsd.org MIME-Version: 1.0 X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D256850 Bug ID: 256850 Summary: poor mac address distribution for if_tap Product: Base System Version: 12.2-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: maxim.shalomikhin@kaspersky.com Created attachment 226064 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D226064&action= =3Dedit Patch for sys/net/if_ethersubr.c I have a system with about 300 tap interfaces (openvpn tunnels) combined in= one bridge. After upgrading from releng/11.4 to releng/12.2 I noticed a lot of repeated MAC (ether) addresses on tap interfaces. How to reproduce: On FreeBSD 12 or 13, create ~100 tap interfaces, then check MACs for uniqueness: ifconfig -a | grep ether | sort | uniq -c | sort -r Quick FIX (change mac from userspace): ifconfig ${ov_dev} ether "00:bd:`jot -r -s ':' -w '%02x' 4`" According to sys/net/ieee_oui.h, MAC address for TAP must be "58:9c:fc:10:XX:XX" (65536 unique macs), but there are two issues with ether_gen_addr(): 1. Fourth byte sometimes "00" and sometimes "10" (minor issue) 2. Fifth byte in ~50% cases is FF (major issue due to char digest[] is sign= ed) So it's only ~256 unique macs for tap and this is very annoying. The small patch (tested on amd64 13.0-RELEASE-p2) attached. --=20 You are receiving this mail because: You are the assignee for the bug.=