[RFC] script for binding ARP <-> IP pairs

Tue Aug 25 01:18:08 UTC 2009

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Doug Barton wrote:
> Xin LI wrote:
>> Any objections for the attached patch?  I'll commit this version if
>> everybody is happy with it and then see if re@ would approve it for
>> 8.0-RELEASE.
> 
> Sorry if I wasn't clear before, but all of the rc.conf variables
> should be prepended with static_arp_ (as opposed to just arp_). So
> rather than arp_args you'd want static_arp_args. I realize you're not
> using set_rcvar() but it's still a good idea to do that for
> consistency's sake, as well as to make it easier for admins to sort
> stuff, etc. Please make sure you change that in the man page as well.

I see.  I have corrected arp_ prefixes to static_arp_ prefixes.  Note
that "arp_args" are not changed because they are intermediate variables
that are intended as "arp(1) arguments".  I have marked these as local.

> Other than that it looks fine to me.
> 
> Silly question that I'm sorry just occurred to me right now, have you
> tested this with IPv6? :)

I think IPv6 would need to use "ndp" instead (cross referenced from
arp(8)) but am not sure.  Because the script rely on space or tab as
separator I think it would just work after a simple s/arp/ndp/g for ndp
but I don't have a local production IPv6 network for the test...

Cheers,
- --
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!
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Index: etc/defaults/rc.conf
===================================================================

--- etc/defaults/rc.conf	(revision 196516)
+++ etc/defaults/rc.conf	(working copy)
@@ -357,6 +357,7 @@
 
 ### Network routing options: ###
 defaultrouter="NO"		# Set to default gateway (or NO).
+static_arp_pairs=""		# Set to static ARP list (or leave empty).
 static_routes=""		# Set to static route list (or leave empty).
 natm_static_routes=""		# Set to static route list for NATM (or leave empty).
 gateway_enable="NO"		# Set to YES if this host will be a gateway.
Index: etc/rc.d/Makefile
===================================================================
--- etc/rc.d/Makefile	(revision 196516)
+++ etc/rc.d/Makefile	(working copy)
@@ -32,7 +32,7 @@
 	random rarpd resolv rfcomm_pppd_server root \
 	route6d routed routing rpcbind rtadvd rwho \
 	savecore sdpd securelevel sendmail \
-	serial sppp statd swap1 \
+	serial sppp statd static_arp swap1 \
 	syscons sysctl syslogd \
 	timed tmp \
 	ugidfw \
Index: etc/rc.d/static_arp
===================================================================
--- etc/rc.d/static_arp	(revision 0)
+++ etc/rc.d/static_arp	(revision 0)
@@ -0,0 +1,71 @@
+#!/bin/sh
+#
+# Copyright (c) 2009  Xin LI <delphij at FreeBSD.org>
+# All rights reserved.
+#
+# 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, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, 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 AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
+#
+# Configure static ARP table
+#
+# $FreeBSD$
+#
+
+# PROVIDE: static_arp
+# REQUIRE: netif
+# KEYWORD: nojail
+
+. /etc/rc.subr
+
+name="static_arp"
+start_cmd="static_arp_start"
+stop_cmd="static_arp_stop"
+
+static_arp_start()
+{
+	if [ -n "${static_arp_pairs}" ]; then
+		echo -n 'Binding static ARP pair(s):'
+		for e in ${static_arp_pairs}; do
+			local arp_args
+			echo -n " ${e}"
+			eval arp_args=\$static_arp_${e}
+			arp -S ${arp_args} >/dev/null 2>&1
+		done
+		echo '.'
+	fi
+}
+
+static_arp_stop()
+{
+	if [ -n "${static_arp_pairs}" ]; then
+		echo -n 'Unbinding static ARP pair(s):'
+		for e in ${static_arp_pairs}; do
+			local arp_args
+			echo -n " ${e}"
+			eval arp_args=\$static_arp_${e}
+			arp -d ${arp_args%%[ 	]*} > /dev/null 2>&1
+		done
+		echo '.'
+	fi
+}
+
+load_rc_config $name
+run_rc_command "$1"
Index: share/man/man5/rc.conf.5
===================================================================
--- share/man/man5/rc.conf.5	(revision 196516)
+++ share/man/man5/rc.conf.5	(working copy)
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 10, 2009
+.Dd August 25, 2009
 .Dt RC.CONF 5
 .Os
 .Sh NAME
@@ -2227,6 +2227,22 @@
 .Pq Vt str
 The IPv6 equivalent of
 .Va defaultrouter .
+.It Va static_arp_pairs
+.Pq Vt str
+Set to the list of static ARP pairs that are to be added at system
+boot time.
+For each whitespace separated
+.Ar element
+in the value, a
+.Va static_arp_ Ns Aq Ar element
+variable is assumed to exist whose contents will later be passed to a
+.Dq Nm arp Cm -S
+operation.
+For example
+.Bd -literal
+static_arp_pairs="gw"
+static_arp_gw="192.168.1.1 00:01:02:03:04:05"
+.Ed
 .It Va static_routes
 .Pq Vt str
 Set to the list of static routes that are to be added at system
