You can now spoof the source address for arping as the third parameter in gateways_eth0 if you have arping2 installed, #180888.

ChangeLog

@@ -1,6 +1,11 @@
 # ChangeLog for Gentoo System Intialization ("rc") scripts
 # Copyright 1999-2007 Gentoo Foundation; Distributed under the GPLv2
 
+  30 Oct 2007; Roy Marples <uberlord@gentoo.org>:
+
+    You can now spoof the source address for arping as the third parameter
+    in gateways_eth0 if you have arping2 installed, #180888.
+
   29 Oct 2007; Roy Marples <uberlord@gentoo.org>:
 
     rc --override foo will override the runlevel to load after boot

conf.d.Linux/net.example

@@ -528,6 +528,13 @@
 #routes_010000000001_334455DDEEFF="default via 10.0.0.1"
 #dns_servers_010000000001_334455DDEEFF="10.0.0.1"
 
+# If you need to spoof the source address, you can add that as third parameter
+# like so
+#gateways_eth0="192.168.0.1,00:11:22:AA:BB:CC,192.168.0.50"
+#or
+#gateways_eth0="192.168.0.1,,192.168.0.50"
+# This requires arping to be installed though
+
 # If we don't find any gateways (or there are none configured) then we try and
 # use APIPA to find a free address in the range 169.254.0.0-169.254.255.255
 # by arping a random address in that range on the interface. If no reply is

net.Linux/arping.sh

@@ -2,12 +2,12 @@
 # Distributed under the terms of the GNU General Public License v2
 
 arping_depend() {
-	program /sbin/arping
+	program /sbin/arping /usr/sbin/arping2
 	before interface
 }
 
 arping_address() {
-	local ip=${1%%/*} mac="$2" foundmac= i= w= opts=
+	local ip=${1%%/*} mac="$2" spoof="$3" foundmac= i= w= opts=
 
 	# We only handle IPv4 addresses
 	case "${ip}" in
@@ -23,10 +23,20 @@ arping_address() {
 	eval w=\$arping_wait_${IFVAR}
 	[ -z "${w}" ] && w=${arping_wait:-5}
 
-	[ -z "$(_get_inet_address)" ] && opts="${opts} -D"
+	if type arping2 >/dev/null 2>&1; then
+		[ -z "$(_get_inet_address)" ] && opts="${opts} -0"
+		[ -n "${spoof}" ] && opts="${opts} -S ${spoof}"
+		while [ ${w} -gt 0 -a -z "${foundmac}" ]; do
+			foundmac="$(arping2 ${opts} -r -c 1 -0 -i "${IFACE}" "${ip}" 2>/dev/null | \
+			sed -e 'y/abcdef/ABCDEF/')"
+			w=$((${w} - 1))
+		done
+	else
+		[ -z "$(_get_inet_address)" ] && opts="${opts} -D"
 
-	foundmac="$(arping -w "${w}" ${opts} -f -I "${IFACE}" "${ip}" 2>/dev/null | \
-			sed -n -e 'y/abcdef/ABCDEF/' -e 's/.*\[\([^]]*\)\].*/\1/p')"
+		foundmac="$(arping -w "${w}" ${opts} -f -I "${IFACE}" "${ip}" 2>/dev/null | \
+		sed -n -e 'y/abcdef/ABCDEF/' -e 's/.*\[\([^]]*\)\].*/\1/p')"
+	fi
 	[ -z "${foundmac}" ] && return 1
 	
 	if [ -n "${mac}" ] ; then
@@ -41,7 +51,7 @@ arping_address() {
 
 _arping_in_config() {
 	_get_array "config_${IFVAR}" | while read i; do
-		[ "${i}" = "arping" ] && return 0
+		[ "${i}" = "arping" ] && return 1
 	done
 	return 1
 }
@@ -51,7 +61,7 @@ arping_start() {
 	einfo "Pinging gateways on ${IFACE} for configuration"
 
 	eval gateways=\$gateways_${IFVAR}
-	if [ -n "${gateways}" ] ; then
+	if [ -z "${gateways}" ] ; then
 		eerror "No gateways have been defined (gateways_${IFVAR}=\"...\")"
 		return 1
 	fi
@@ -61,7 +71,7 @@ arping_start() {
 	for x in ${gateways}; do
 		local IFS=,
 		set -- ${x}
-		local ip=$1 mac=$2 extra=
+		local ip=$1 mac=$2 spoof=$3 extra=
 		unset IFS
 
 		if [ -n "${mac}" ] ; then
@@ -70,9 +80,8 @@ arping_start() {
 		fi
 
 		vebegin "${ip} ${extra}"
-		if arping_address "${ip}" "${mac}" ; then
-			local OIFS=$IFS SIFS=${IFS-y}
-			IFS=.
+		if arping_address "${ip}" "${mac}" "${spoof}" ; then
+			local IFS=.
 			for i in ${ip} ; do
 				if [ "${#i}" = "2" ] ; then
 					conf="${conf}0${i}"
@@ -82,28 +91,28 @@ arping_start() {
 					conf="${conf}${i}"
 				fi
 			done
-			if [ "${SIFS}" = "y" ] ; then
-				IFS=$OFIS
-			else
-				unset IFS
-			fi
+			unset IFS
 			[ -n "${mac}" ] && conf="${conf}_$(echo "${mac}" | sed -e 's/://g')"
 
-			veend 0
+			eend 0
 			eoutdent
 			veinfo "Configuring ${IFACE} for ${ip} ${extra}"
-			_configure_variables "${conf}"
+			_configure_variables ${conf}
 
 			# Call the system module as we've aleady passed it by ....
 			# And it *has* to be pre_start for other things to work correctly
 			system_pre_start
 
 			# Ensure that we have a valid config - ie arping is no longer there
-			if _arping_in_config; then
-				veend 1 "No config found for ${ip} (config_${conf}=\"...\")"
-				continue 2
-			fi
-
+			local IFS="$__IFS"
+			for i in $(_get_array "config_${IFVAR}"); do
+				if [ "${i}" = "arping" ]; then
+					eend 1 "No config found for ${ip} (config_${conf}=\"...\")"
+					continue 2
+				fi
+			done
+			unset IFS
+			
 			_load_config
 			return 0
 		fi