wg-quick: if resolvconf/interface-order exists, use it

Some older broken resolvconf implementations ignore -m, but do have an
interface-order list. It's better to use this list dynamically, in case
it changes, or in case it's not used by the OS's resolvconf
implementation, such as in the case of systemd or openresolv.

1 files changed, 12 insertions, 3 deletions

diff --git a/src/tools/wg-quick.bash b/src/tools/wg-quick.bash
index af72f7d..e93fb80 100755
--- a/src/tools/wg-quick.bash
+++ b/src/tools/wg-quick.bash
@@ -136,16 +136,25 @@ set_mtu() {
 	cmd ip link set mtu $(( mtu - 80 )) dev "$INTERFACE"
 }
 
+resolvconf_iface_prefix() {
+	[[ -f /etc/resolvconf/interface-order ]] || return 0
+	local iface
+	while read -r iface; do
+		[[ $iface =~ ^([A-Za-z0-9-]+)\*$ ]] || continue
+		echo "${BASH_REMATCH[1]}." && return 0
+	done < /etc/resolvconf/interface-order
+}
+
 HAVE_SET_DNS=0
 set_dns() {
 	[[ ${#DNS[@]} -gt 0 ]] || return 0
-	printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a "tun.$INTERFACE" -m 0 -x
+	printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a "$(resolvconf_iface_prefix)$INTERFACE" -m 0 -x
 	HAVE_SET_DNS=1
 }
 
 unset_dns() {
 	[[ ${#DNS[@]} -gt 0 ]] || return 0
-	cmd resolvconf -d "tun.$INTERFACE"
+	cmd resolvconf -d "$(resolvconf_iface_prefix)$INTERFACE"
 }
 
 add_route() {
@@ -194,7 +203,7 @@ save_config() {
 	done
 	while read -r address; do
 		[[ $address =~ ^nameserver\ ([a-zA-Z0-9_=+:%.-]+)$ ]] && new_config+="DNS = ${BASH_REMATCH[1]}"$'\n'
-	done < <(resolvconf -l "tun.$INTERFACE" 2>/dev/null)
+	done < <(resolvconf -l "$(resolvconf_iface_prefix)$INTERFACE" 2>/dev/null)
 	[[ -n $MTU && $(ip link show dev "$INTERFACE") =~ mtu\ ([0-9]+) ]] && new_config+="MTU = ${BASH_REMATCH[1]}"$'\n'
 	[[ -n $TABLE ]] && new_config+="Table = $TABLE"$'\n'
 	[[ $SAVE_CONFIG -eq 0 ]] || new_config+=$'SaveConfig = true\n'