[source] dnsmasq: fix dhcp-host entries with empty macs

[LEDE Commits]

jow pushed a commit to source.git, branch master:
https://git.lede-project.org/fcfd5cdb59d25d4bd1ec410f32b452c139f5e288

commit fcfd5cdb59d25d4bd1ec410f32b452c139f5e288
Author: Jo-Philipp Wich <jo at mein.io>
AuthorDate: Tue Nov 28 11:38:40 2017 +0000

    dnsmasq: fix dhcp-host entries with empty macs
    
    Due to improper localization of helper variables, "config host" entries
    without a given mac address may inherit the mac address of a preceeding,
    leading to invalid generated netive configuration.
    
    Fix the issue by marking the "macs" and "tags" helper variables in
    dhcp_host_add() local, avoiding the need for explicitely resetting them
    with each invocation.
    
    Reported-by: Russell Senior <russell at personaltelco.net>
    Tested-by: Kevin Darbyshire-Bryant <ldir at darbyshire-bryant.me.uk>
    Signed-off-by: Jo-Philipp Wich <jo at mein.io>
---
 package/network/services/dnsmasq/files/dnsmasq.init | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/package/network/services/dnsmasq/files/dnsmasq.init b/package/network/services/dnsmasq/files/dnsmasq.init
index 88c2ce6..2fd56ed 100644
--- a/package/network/services/dnsmasq/files/dnsmasq.init
+++ b/package/network/services/dnsmasq/files/dnsmasq.init
@@ -277,7 +277,7 @@ dhcp_match_add() {
 
 dhcp_host_add() {
 	local cfg="$1"
-	local hosttag nametime addrs duids
+	local hosttag nametime addrs duids macs tags
 
 	config_get_bool force "$cfg" force 0
 
@@ -305,7 +305,6 @@ dhcp_host_add() {
 	if [ -n "$mac" ]; then
 		# --dhcp-host=00:20:e0:3b:13:af,192.168.0.199,lap
 		# many MAC are possible to track a laptop ON/OFF dock
-		macs=""
 		for m in $mac; do append macs "$m" ","; done
 	fi
 
@@ -326,7 +325,6 @@ dhcp_host_add() {
 		hex_to_hostid hostid "$hostid"
 	fi
 
-	tags=""
 	if [ -n "$tag" ]; then
 		for t in $tag; do append tags "$t" ",set:"; done
 	fi