From 42bee2ae2f3fb60dc13ef96b403255401a85bcc0 Mon Sep 17 00:00:00 2001
From: Nyr <me@nyr.be>
Date: Fri, 29 May 2020 14:15:39 +0200
Subject: [PATCH] egrep IP regex optimizations

Thanks @sorcun
---
 wireguard-install.sh | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/wireguard-install.sh b/wireguard-install.sh
index 1914825..97db97a 100644
--- a/wireguard-install.sh
+++ b/wireguard-install.sh
@@ -116,7 +116,7 @@ new_client_dns () {
 				resolv_conf="/etc/resolv.conf"
 			fi
 			# Extract nameservers and provide them in the required format
-			dns=$(grep -v '#' "$resolv_conf" | grep nameserver | grep -E -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | xargs | sed -e 's/ /, /g')
+			dns=$(grep -v '#' "$resolv_conf" | grep nameserver | grep -E -o '[0-9]{1,3}(\.[0-9]{1,3}){3}' | xargs | sed -e 's/ /, /g')
 		;;
 		2)
 			dns="8.8.8.8, 8.8.4.4"
@@ -179,27 +179,27 @@ if [[ ! -e /etc/wireguard/wg0.conf ]]; then
 	clear
 	echo 'Welcome to this WireGuard road warrior installer!'
 	# If system has a single IPv4, it is selected automatically. Else, ask the user
-	if [[ $(ip -4 addr | grep inet | grep -vEc '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}') -eq 1 ]]; then
-		ip=$(ip -4 addr | grep inet | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}')
+	if [[ $(ip -4 addr | grep inet | grep -vEc '127(\.[0-9]{1,3}){3}') -eq 1 ]]; then
+		ip=$(ip -4 addr | grep inet | grep -vE '127(\.[0-9]{1,3}){3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}(\.[0-9]{1,3}){3}')
 	else
-		number_of_ip=$(ip -4 addr | grep inet | grep -vEc '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}')
+		number_of_ip=$(ip -4 addr | grep inet | grep -vEc '127(\.[0-9]{1,3}){3}')
 		echo
 		echo "Which IPv4 address should be used?"
-		ip -4 addr | grep inet | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | nl -s ') '
+		ip -4 addr | grep inet | grep -vE '127(\.[0-9]{1,3}){3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}(\.[0-9]{1,3}){3}' | nl -s ') '
 		read -p "IPv4 address [1]: " ip_number
 		until [[ -z "$ip_number" || "$ip_number" =~ ^[0-9]+$ && "$ip_number" -le "$number_of_ip" ]]; do
 			echo "$ip_number: invalid selection."
 			read -p "IPv4 address [1]: " ip_number
 		done
 		[[ -z "$ip_number" ]] && ip_number="1"
-		ip=$(ip -4 addr | grep inet | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | sed -n "$ip_number"p)
+		ip=$(ip -4 addr | grep inet | grep -vE '127(\.[0-9]{1,3}){3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}(\.[0-9]{1,3}){3}' | sed -n "$ip_number"p)
 	fi
 	# If $ip is a private IP address, the server must be behind NAT
 	if echo "$ip" | grep -qE '^(10\.|172\.1[6789]\.|172\.2[0-9]\.|172\.3[01]\.|192\.168)'; then
 		echo
 		echo "This server is behind NAT. What is the public IPv4 address or hostname?"
 		# Get public IP and sanitize with grep
-		get_public_ip=$(grep -m 1 -oE '^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$' <<< "$(wget -T 10 -t 1 -4qO- "http://ip1.dynupdate.no-ip.com/" || curl -m 10 -4Ls "http://ip1.dynupdate.no-ip.com/")")
+		get_public_ip=$(grep -m 1 -oE '^[0-9]{1,3}(\.[0-9]{1,3}){3}$' <<< "$(wget -T 10 -t 1 -4qO- "http://ip1.dynupdate.no-ip.com/" || curl -m 10 -4Ls "http://ip1.dynupdate.no-ip.com/")")
 		read -p "Public IPv4 address / hostname [$get_public_ip]: " public_ip
 		# If the checkip service is unavailable and user didn't provide input, ask again
 		until [[ -n "$get_public_ip" || -n "$public_ip" ]]; do