From 1e9cfc0fbbf2c64d1c867c78c0e6d0758cdb47aa Mon Sep 17 00:00:00 2001
From: brnl <3243133+brnl@users.noreply.github.com>
Date: Fri, 28 Feb 2020 00:21:13 +0100
Subject: [PATCH] Allow split-tunnel via custom CIDR blocks

This change allows the tunnel to be split-tunnel, routing only the selected subnets through the tunnel. The notation is in CIDR-format.
Example usage:

`sudo PUSH_CIDR_BLOCKS=(192.168.1.0/24 172.16.0.0/16) ./openvpn-install.sh`
---
 openvpn-install.sh | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/openvpn-install.sh b/openvpn-install.sh
index 90ea433..2d86ff0 100755
--- a/openvpn-install.sh
+++ b/openvpn-install.sh
@@ -787,7 +787,26 @@ ifconfig-pool-persist ipp.txt" >> /etc/openvpn/server.conf
 		fi
 		;;
 	esac
-	echo 'push "redirect-gateway def1 bypass-dhcp"' >> /etc/openvpn/server.conf
+
+	# Allow split-tunnel via custom CIDR blocks (ie. 192.168.0.0/24)
+	if [ ${#PUSH_CIDR_BLOCKS[@]} -gt 0 ]; then
+		for cidr in ${PUSH_CIDR_BLOCKS[@]}; do
+			echo "Adding $cidr to routed subnets...";
+			ROUTE_IP=$(echo $cidr | cut -d"/" -f1)
+			ROUTE_BITS=$(echo $cidr | cut -d"/" -f2)
+
+			case $ROUTE_BITS in 
+				8)  ROUTE_MASK="255.0.0.0" ;;
+				16) ROUTE_MASK="255.255.0.0" ;;
+				24) ROUTE_MASK="255.255.255.0" ;;
+				32) ROUTE_MASK="255.255.255.255" ;;
+			esac
+
+			echo "push \"route ${ROUTE_IP} ${ROUTE_MASK}\"" >> /etc/openvpn/server.conf
+		done
+	else
+		echo 'push "redirect-gateway def1 bypass-dhcp"' >> /etc/openvpn/server.conf
+	fi
 
 	# IPv6 network settings if needed
 	if [[ "$IPV6_SUPPORT" = 'y' ]]; then