1 files changed, 134 insertions, 0 deletions
diff --git a/write_net_rules b/write_net_rules
new file mode 100644
index 0000000..5626820
--- /dev/null
+++ b/write_net_rules
@@ -0,0 +1,134 @@
+#!/bin/sh -e
+#
+# Copyright (C) 2006 Marco d'Itri <md@Linux.IT>
+# Copyright (C) 2007 Kay Sievers <kay.sievers@vrfy.org>
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation version 2 of the License.
+#
+# This script is run to create persistent network device naming rules
+# based on properties of the device.
+# If the interface needs to be renamed, INTERFACE_NEW=<name> will be printed
+# on stdout to allow udev to IMPORT it.
+
+# variables used to communicate:
+#   MATCHADDR             MAC address used for the match
+#   MATCHID               bus_id used for the match
+#   MATCHDEVID            dev_id used for the match
+#   MATCHDRV              driver name used for the match
+#   MATCHIFTYPE           interface type match
+#   COMMENT               comment to add to the generated rule
+#   INTERFACE_NAME        requested name supplied by external tool
+#   INTERFACE_NEW         new interface name returned by rule writer
+
+RULES_FILE='/etc/udev/rules.d/50-persistent-net.rules'
+
+. /usr/lib/udev/rule_generator.functions
+
+interface_name_taken() {
+	local value="$(find_all_rules 'NAME=' $INTERFACE)"
+	if [ "$value" ]; then
+		return 0
+	else
+		return 1
+	fi
+}
+
+find_next_available() {
+	raw_find_next_available "$(find_all_rules 'NAME=' "$1")"
+}
+
+write_rule() {
+	local match="$1"
+	local name="$2"
+	local comment="$3"
+
+	{
+	if [ "$PRINT_HEADER" ]; then
+		PRINT_HEADER=
+		echo "# This file was automatically generated by the $0"
+		echo "# program, run by the persistent-net-generator.rules rules file."
+		echo "#"
+		echo "# You can modify it, as long as you keep each rule on a single"
+		echo "# line, and change only the value of the NAME= key."
+	fi
+
+	echo ""
+	[ "$comment" ] && echo "# $comment"
+	echo "SUBSYSTEM==\"net\", ACTION==\"add\"$match, NAME=\"$name\""
+	} >> $RULES_FILE
+}
+
+if [ -z "$INTERFACE" ]; then
+	echo "missing \$INTERFACE" >&2
+	exit 1
+fi
+
+mkdir -p /dev/.udev
+
+# Prevent concurrent processes from modifying the file at the same time.
+lock_rules_file
+
+# Check if the rules file is writeable.
+choose_rules_file
+
+# the DRIVERS key is needed to not match bridges and VLAN sub-interfaces
+if [ "$MATCHADDR" ]; then
+	match="$match, DRIVERS==\"?*\", ATTR{address}==\"$MATCHADDR\""
+fi
+
+if [ "$MATCHDRV" ]; then
+	match="$match, DRIVERS==\"$MATCHDRV\""
+fi
+
+if [ "$MATCHDEVID" ]; then
+	match="$match, ATTR{dev_id}==\"$MATCHDEVID\""
+fi
+
+if [ "$MATCHID" ]; then
+	match="$match, KERNELS==\"$MATCHID\""
+fi
+
+if [ "$MATCHIFTYPE" ]; then
+	match="$match, ATTR{type}==\"$MATCHIFTYPE\""
+fi
+
+if [ -z "$match" ]; then
+	echo "missing valid match" >&2
+	unlock_rules_file
+	exit 1
+fi
+
+basename=${INTERFACE%%[0-9]*}
+match="$match, KERNEL==\"$basename*\""
+
+if [ "$INTERFACE_NAME" ]; then
+	# external tools may request a custom name
+	COMMENT="$COMMENT (custom name provided by external tool)"
+	if [ "$INTERFACE_NAME" != "$INTERFACE" ]; then
+		INTERFACE=$INTERFACE_NAME;
+		echo "INTERFACE_NEW=$INTERFACE"
+	fi
+else
+	# if a rule using the current name already exists, find a new name
+	if interface_name_taken; then
+		INTERFACE="$basename$(find_next_available "$basename[0-9]*")"
+		echo "INTERFACE_NEW=$INTERFACE"
+	fi
+fi
+
+if [ "$MATCHADDR" ]; then
+	mac_found=0
+	grep -qE "^\s*[^#].*==\"$MATCHADDR\"" "$RULES_FILE" || mac_found=$?
+	if [ $mac_found -ne 0 ]; then
+		# only add new rules while mac address not found
+		write_rule "$match" "$INTERFACE" "$COMMENT"
+	fi
+else
+	write_rule "$match" "$INTERFACE" "$COMMENT"
+fi
+
+unlock_rules_file
+
+exit 0