commit 3535171185c3dbb99a85a09207cd40e6431b8292
Author: Bill Yuan <bycn82@gmail.com>
Date:   Thu Oct 5 01:52:46 2017 +0000

    rc: rename interface according to the MAC
    
    add func `ifconfig_rename_by_mac` which will try to rename the
    interface according to the configured MAC address.
    e.g. (config in rc.conf)
    	ifconfig_rename_ifs="em0 em1"
    	ifconfig_rename_em1_by_mac="08:00:27:a9:46:c7"
    	ifconfig_rename_em0_by_mac="08:00:27:2d:60:a6"

diff --git a/etc/network.subr b/etc/network.subr
index ba2d5f8..5cd8d0d 100644
--- a/etc/network.subr
+++ b/etc/network.subr
@@ -370,6 +370,59 @@ ifnet_rename()
 	return 0
 }
 
+# ifconfig_rename_by_mac
+#	config in rc.conf
+#	ifconfig_rename_ifs "<if> [if]"
+#	ifconfig_rename_<if>_by_mac="<MAC>"
+#
+ifconfig_rename_by_mac()
+{
+	prefix="ifconfig_rename_"
+	subfix="_by_mac"
+	#collect all mac addresses
+	ifs="`ifconfig -l ether`"
+	[ -z "$ifs" ] && return 0
+	all=""
+	for ifname_tmp in ${ifs} ; do
+		mac=`ifconfig $ifname_tmp ether | grep ether | cut -d ' ' -f 2`
+		all="$mac|$all"
+	done
+	
+	delta=0
+	sec1=0
+	for cfg_ifname in ${ifconfig_rename_ifs} ; do
+		#get the config mac
+		cfg="$`echo "\$prefix$cfg_ifname$subfix"`"
+		mac=`eval echo $cfg`
+		#whether the mac is exits in system
+		found=`echo $all | awk -v mac=$mac -F '|' '{for(i=1; i < NF; i++){if($i == mac){ print "FOUND";}}}'`
+		if [ "$found" == "FOUND" ]; then
+			#get current ifname by mac address
+			ifs="`ifconfig -l ether`"
+			for ifname_tmp in ${ifs} ; do
+				the=`ifconfig $ifname_tmp ether | grep ether | cut -d ' ' -f 2`
+				if [ $mac == $the ]; then
+					curr_name=$ifname_tmp
+				fi
+			done
+			if [ $curr_name != $cfg_ifname ]; then
+				#rename if another interface is using the name
+				ifconfig $cfg_ifname >> /dev/null
+				if [ $? == 0 ]; then
+					sec2=`date +%s`
+					if [ $sec1 == $sec2 ]; then
+						delta=`expr $delta + 1`
+					fi
+					ifconfig $cfg_ifname name `expr $sec2 + $delta`
+					sec1=$sec2
+				fi
+				ifconfig $curr_name name $cfg_ifname
+			fi
+		fi
+	done
+	return 0
+}
+
 #
 # list_net_interfaces type
 #	List all network interfaces. The type of interface returned
diff --git a/etc/rc.d/netif b/etc/rc.d/netif
index 222220b..d1de54d 100644
--- a/etc/rc.d/netif
+++ b/etc/rc.d/netif
@@ -56,6 +56,9 @@ network_start()
 		# Create IPv6<-->IPv4 tunnels
 		gif_up
 
+		# Rename interfaces by MAC
+		ifconfig_rename_by_mac
+
 		# Rename interfaces.
 		ifnet_rename
 	fi