Date: Fri, 20 Aug 2021 21:32:44 GMT From: Kevin Bowling <kbowling@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 32294ca07393 - stable/13 - man: document ether_gen_addr(9) Message-ID: <202108202132.17KLWiGR081901@gitrepo.freebsd.org>
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The branch stable/13 has been updated by kbowling (ports committer): URL: https://cgit.FreeBSD.org/src/commit/?id=32294ca07393dee40cb85a872a6dce9532f360ce commit 32294ca07393dee40cb85a872a6dce9532f360ce Author: Kyle Evans <kevans@FreeBSD.org> AuthorDate: 2021-04-16 01:08:27 +0000 Commit: Kevin Bowling <kbowling@FreeBSD.org> CommitDate: 2021-08-20 21:32:23 +0000 man: document ether_gen_addr(9) This KPI is used to assign a MAC address to an interface that doesn't already have one assigned. Reviewed by: bcr, gnn, imp, kbowling, kp MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D29787 (cherry picked from commit e58a65ccdac352712e19a60fffa57a86afabbde9) --- share/man/man9/Makefile | 1 + share/man/man9/ether_gen_addr.9 | 79 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile index 0c874e77cf0a..43bf82426a73 100644 --- a/share/man/man9/Makefile +++ b/share/man/man9/Makefile @@ -137,6 +137,7 @@ MAN= accept_filter.9 \ DRIVER_MODULE.9 \ efirt.9 \ epoch.9 \ + ether_gen_addr.9 \ EVENTHANDLER.9 \ eventtimers.9 \ extattr.9 \ diff --git a/share/man/man9/ether_gen_addr.9 b/share/man/man9/ether_gen_addr.9 new file mode 100644 index 000000000000..1b98a841736d --- /dev/null +++ b/share/man/man9/ether_gen_addr.9 @@ -0,0 +1,79 @@ +.\" +.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD +.\" +.\" Copyright (C) 2021 Kyle Evans <kevans@FreeBSD.org> +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice(s), this list of conditions and the following disclaimer as +.\" the first lines of this file unmodified other than the possible +.\" addition of one or more copyright notices. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice(s), this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY +.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY +.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH +.\" DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd June 1, 2021 +.Dt ETHER_GEN_ADDR 9 +.Os +.Sh NAME +.Nm ether_gen_addr +.Nd "generate an arbitrary MAC address for use" +.Sh SYNOPSIS +.In sys/types.h +.In sys/socket.h +.In net/if.h +.In net/if_var.h +.In net/ethernet.h +.Ft void +.Fn ether_gen_addr "struct ifnet *ifp" "struct ether_addr *hwaddr" +.Sh DESCRIPTION +The +.Fn ether_gen_addr +function generates an arbitrary MAC address for use by an ethernet interface +that does not have an assigned address. +.Pp +By default, +.Nm +attempts to generate a stable MAC address using the hostid of the jail that +the +.Ar ifp +is being added to. +During early boot, the hostid may not be set on machines that haven't yet +populated +.Pa /etc/hostid , +or on machines that do not use +.Xr loader 8 . +.Pp +.Nm +can fail to derive a MAC address due to memory allocation failure. +In this case, a locally-administered unicast MAC address will be randomly +generated and returned via the +.Ar hwaddr +parameter. +.Pp +If +.Nm +succeeds, then it will return a MAC address in the FreeBSD Foundation OUI, +.Dq 58:9c:fc , +via the +.Ar hwaddr +parameter. +.Sh AUTHORS +This manual page was written by +.An Kyle Evans Aq Mt kevans@FreeBSD.org .
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