From 21ee63b7fb77da949eca5aca710afade971a0236 Mon Sep 17 00:00:00 2001
From: Dan Schaper <dschaper@users.noreply.github.com>
Date: Wed, 25 Nov 2015 14:08:13 -0800
Subject: [PATCH] Get IP info from outgoing interface

Use IP to get interface information from outgoing interface. Use CIDR notation to make things easier.
---
 automated install/basic-install.sh | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/automated install/basic-install.sh b/automated install/basic-install.sh
index f0a7d139..f2a98fb7 100755
--- a/automated install/basic-install.sh	
+++ b/automated install/basic-install.sh	
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Pi-hole: A black hole for Internet advertisements
 # by Jacob Salmela
 # Network-wide ad blocking via your Raspberry Pi
@@ -24,9 +24,11 @@ columns=$(stty -a | tr \; \\012 | egrep 'columns' | cut -d' ' -f3)
 r=$(( rows / 2 ))
 c=$(( columns / 2 ))
 
-IPv4addr=$(ip -4 addr show | awk '{match($0,/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/); ip = substr($0,RSTART,RLENGTH); print ip}' | sed '/^\s*$/d' | grep -v "127.0.0.1")
-IPv4mask=$(ifconfig | awk -F':' '/inet addr/ && !/127.0.0.1/ {print $4}')
-IPv4gw=$(ip route show | awk '/default\ via/ {print $3}')
+# Find IP used to route to outside world
+IPv4info=$(ip route get 8.8.8.8)
+IPv4dev=$(echo $IPv4info| awk '{print $5}')
+IPv4addr=$(ip -o -f inet addr show dev $IPv4dev | awk '{print $4}')
+IPv4gw=$(echo $IPv4info | awk '{print $3}')
 
 # IPv6 support to be added later
 #IPv6eui64=$(ip addr show | awk '/scope\ global/ && /ff:fe/ {print $2}' | cut -d'/' -f1)
@@ -117,7 +119,6 @@ getStaticIPv4Settings()
 if (whiptail --backtitle "Calibrating network interface" --title "Static IP Address" --yesno "Do you want to use your current network settings as a static address?
 
 								IP address:    $IPv4addr
-								Subnet mask:   $IPv4mask
 								Gateway:       $IPv4gw" $r $c) then
 	# If they choose yes, let the user know that the IP address will not be available via DHCP and may cause a conflict.
 	whiptail --msgbox --backtitle "IP information" --title "FYI: IP Conflict" "It is possible your router could still try to assign this IP to a device, which would cause a conflict.  But in most cases the router is smart enough to not do that.
@@ -138,22 +139,17 @@ else
 	IPv4addr=$(whiptail --backtitle "Calibrating network interface" --title "IPv4 address" --inputbox "Enter your desired IPv4 address" $r $c $IPv4addr 3>&1 1>&2 2>&3)
 	if [[ $? = 0 ]];then
     	echo "Your static IPv4 address:    $IPv4addr"
-		# Ask for the subnet mask
-		IPv4mask=$(whiptail --backtitle "Calibrating network interface" --title "IPv4 netmask" --inputbox "Enter your desired IPv4 subnet mask" $r $c $IPv4mask 3>&1 1>&2 2>&3)
-		if [[ $? = 0 ]];then
-			echo "Your static IPv4 netmask:    $IPv4mask"
-			# Ask for the gateway
+		# Ask for the gateway
 			IPv4gw=$(whiptail --backtitle "Calibrating network interface" --title "IPv4 gateway (router)" --inputbox "Enter your desired IPv4 default gateway" $r $c $IPv4gw 3>&1 1>&2 2>&3)
 			if [[ $? = 0 ]];then
 				echo "Your static IPv4 gateway:    $IPv4gw"
 				# Give the user a chance to review their settings before moving on
 				if (whiptail --backtitle "Calibrating network interface" --title "Static IP Address" --yesno "Are these settings correct?
 					IP address:    $IPv4addr
-					Subnet mask:   $IPv4mask
 					Gateway:       $IPv4gw" $r $c)then
 					# If the settings are correct, then we need to set the piholeIP
 					# Saving it to a temporary file us to retrieve it later when we run the gravity.sh script
-					echo $IPv4addr > /tmp/piholeIP
+					echo ${IPv4addr%/*} > /tmp/piholeIP
 					# After that's done, the loop ends and we move on
 					ipSettingsCorrect=True
 				else
@@ -167,12 +163,6 @@ else
 				exit
 			fi
 		else
-			# Cancelling subnet mask settings window
-			ipSettingsCorrect=False
-			echo "User canceled."
-			exit
-		fi
-	else
 		# Cancelling IPv4 settings window
 		ipSettingsCorrect=False
 		echo "User canceled."
@@ -188,7 +178,7 @@ setStaticIPv4()
 {
 # Append these lines to /etc/dhcpcd.conf to enable a static IP
 echo "interface $piholeInterface
-static ip_address=$IPv4addr/24
+static ip_address=$IPv4addr
 static routers=$IPv4gw
 static domain_name_servers=$IPv4gw" | sudo tee -a $dhcpcdFile >/dev/null
 }