genmac: Replace RANDOM_MAC in network/interfaces with a randomly generated MAC

For machines that do not have a MAC in hardware and with drivers that don't
generate a random one in the kernel, this init script will replace the string
RANDOM_MAC in the network/interfaces file with one generated with "ranpwd -m".
Care is taken to ensure multiple interfaces can use RANDOM_MAC and receive
unique addresses. ranpwd generates MACs with the locally administered bit set
and the multicast bit disabled.

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Joshua Lock <josh@linux.intel.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/meta-sys940x/recipes-bsp/genmac/files/genmac b/meta-sys940x/recipes-bsp/genmac/files/genmac
new file mode 100644
index 00000000..1899e95f
--- /dev/null
+++ b/meta-sys940x/recipes-bsp/genmac/files/genmac
@@ -0,0 +1,46 @@
+#!/bin/sh
+### BEGIN INIT INFO
+# Provides:          Random MAC address generator
+# Required-Start:    $syslog
+# Required-Stop:     $syslog
+# Default-Start:     2 3 4 5
+# Default-Stop:      0 1 6
+# Short-Description: Set a random MAC for tagged interfaces
+# Description:       Set a random MAC for interfaces with RANDOM_MAC
+### END INIT INFO
+
+# Author: Darren Hart <dvhart@linux.intel.com>
+# Based on /etc/init.d/skeleton
+
+PATH=/sbin:/usr/sbin:/bin:/usr/bin
+DESC="Set a random MAC for tagged interfaces"
+NAME=genmac
+RANPWD=`which ranpwd`
+SCRIPTNAME=/etc/init.d/$NAME
+
+# Exit if ranpwd is not installed
+[ -x "$RANPWD" ] || exit 0
+
+do_start() {
+        # Replace every occurence of RANDOM_MAC with a unique locally
+        # administered, unicast, randomly generated MAC address.
+        while grep -q RANDOM_MAC /etc/network/interfaces; do
+                sed -i "1,/RANDOM_MAC/s/RANDOM_MAC/$($RANPWD -m)/" /etc/network/interfaces
+        done
+}
+
+case "$1" in
+start)
+        echo "$NAME: Setting random MAC addresses"
+        do_start
+        ;;
+stop)
+        ;;
+*)
+        echo "Usage: $SCRIPTNAME {start|stop}" >&2
+        exit 3
+        ;;
+esac
+
+exit 0
+