From 0e8666d46d353dd8db3d7060485a44d332bf6dc5 Mon Sep 17 00:00:00 2001
From: Daniel Lenski <dlenski@gmail.com>
Date: Tue, 8 Sep 2020 19:23:35 -0700
Subject: [PATCH] leave support for older systemd-resolved (v229-v238) in place

Signed-off-by: Daniel Lenski <dlenski@gmail.com>
---
 vpnc-script | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

diff --git a/vpnc-script b/vpnc-script
index 6cae9cf..ac67c37 100755
--- a/vpnc-script
+++ b/vpnc-script
@@ -131,9 +131,13 @@ if [ -r /etc/openwrt_release ] && [ -n "$OPENWRT_INTERFACE" ]; then
 	MODIFYRESOLVCONF=modify_resolvconf_openwrt
 	RESTORERESOLVCONF=restore_resolvconf_openwrt
 elif [ -x /usr/bin/resolvectl ] && [ ${RESOLVEDENABLED} = 1 ]; then
-	# For systemd-resolved (version 229 and above)
+	# For systemd-resolved (version 239 and above)
 	MODIFYRESOLVCONF=modify_resolved_manager
 	RESTORERESOLVCONF=restore_resolved_manager
+elif [ -x /usr/bin/busctl ] && [ ${RESOLVEDENABLED} = 1 ]; then
+	# For systemd-resolved (version 229 and above)
+	MODIFYRESOLVCONF=modify_resolved_manager_old
+	RESTORERESOLVCONF=restore_resolved_manager_old
 elif [ -x /sbin/resolvconf ]; then
 	# Optional tool on Debian, Ubuntu, Gentoo and FreeBSD
 	MODIFYRESOLVCONF=modify_resolvconf_manager
@@ -699,12 +703,33 @@ restore_resolvconf_manager() {
 	/sbin/resolvconf -d $TUNDEV
 }
 
+AF_INET=2
+
 get_if_index() {
 	local link
 	link="$(ip link show dev "$1")" || return $?
 	echo ${link} | awk -F: '{print $1}'
 }
 
+busctl_call() {
+	local dest node
+	dest=org.freedesktop.resolve1
+	node=/org/freedesktop/resolve1
+	busctl call "$dest" "${node}" "${dest}.Manager" "$@"
+}
+
+busctl_set_nameservers() {
+	local if_index addresses args addr
+	if_index=$1
+	shift
+	addresses="$@"
+	args="$if_index $#"
+	for addr in ${addresses}; do
+		args="$args ${AF_INET} 4 $(echo $addr | sed 's/[.]/ /g')"
+	done
+	busctl_call SetLinkDNS 'ia(iay)' ${args}
+}
+
 resolvectl_set_nameservers() {
 	local if_index addresses
 	if_index=$1
@@ -713,6 +738,18 @@ resolvectl_set_nameservers() {
 	/usr/bin/resolvectl dns $if_index $addresses
 }
 
+busctl_set_search() {
+	local if_index domains args domain
+	if_index=$1
+	shift
+	domains="$@"
+	args="$if_index $#"
+	for domain in ${domains}; do
+		args="$args ${domain} false"
+	done
+	busctl_call SetLinkDomains 'ia(sb)' ${args}
+}
+
 resolvectl_set_search() {
 	local if_index domains
 	if_index=$1
@@ -731,12 +768,27 @@ modify_resolved_manager() {
 	fi
 }
 
+modify_resolved_manager_old() {
+	local if_index
+	if_index=$(get_if_index $TUNDEV)
+	busctl_set_nameservers $if_index $INTERNAL_IP4_DNS
+	if [ -n "$CISCO_DEF_DOMAIN" ]; then
+		busctl_set_search $if_index $CISCO_DEF_DOMAIN
+	fi
+}
+
 restore_resolved_manager() {
 	local if_index
 	if_index=$(get_if_index $TUNDEV)
 	/usr/bin/resolvectl revert $if_index
 }
 
+restore_resolved_manager_old() {
+	local if_index
+	if_index=$(get_if_index $TUNDEV)
+	busctl_call RevertLink 'i' $if_index
+}
+
 # === resolv.conf handling via unbound =========
 
 modify_resolvconf_unbound() {
-- 
2.50.1