From ed5cbb865f193ee740659bcc76aa1d7ff49ce942 Mon Sep 17 00:00:00 2001
From: hwdsl2 <hwdsl2@users.noreply.github.com>
Date: Sat, 12 Jan 2019 00:44:23 -0600
Subject: [PATCH] Clean up network detection

- Clean up default network interface detection and remove VPN_NET_IFACE
---
 vpnsetup.sh        | 22 +++++++---------------
 vpnsetup_centos.sh | 22 +++++++---------------
 2 files changed, 14 insertions(+), 30 deletions(-)

diff --git a/vpnsetup.sh b/vpnsetup.sh
index 0892ac1..3d3db0e 100755
--- a/vpnsetup.sh
+++ b/vpnsetup.sh
@@ -69,10 +69,8 @@ if [ "$(id -u)" != 0 ]; then
   exiterr "Script must be run as root. Try 'sudo sh $0'"
 fi
 
-NET_IFACE=${VPN_NET_IFACE:-'eth0'}
-def_iface="$(route 2>/dev/null | grep '^default' | grep -o '[^ ]*$')"
-[ -z "$def_iface" ] && def_iface="$(ip -4 route list 0/0 2>/dev/null | grep -Po '(?<=dev )(\S+)')"
-
+def_iface=$(route 2>/dev/null | grep '^default' | grep -o '[^ ]*$')
+[ -z "$def_iface" ] && def_iface=$(ip -4 route list 0/0 2>/dev/null | grep -Po '(?<=dev )(\S+)')
 def_state=$(cat "/sys/class/net/$def_iface/operstate" 2>/dev/null)
 if [ -n "$def_state" ] && [ "$def_state" != "down" ]; then
   if ! uname -m | grep -qi '^arm'; then
@@ -83,18 +81,12 @@ if [ -n "$def_state" ] && [ "$def_state" != "down" ]; then
     esac
   fi
   NET_IFACE="$def_iface"
-fi
-
-net_state=$(cat "/sys/class/net/$NET_IFACE/operstate" 2>/dev/null)
-if [ -z "$net_state" ] || [ "$net_state" = "down" ] || [ "$NET_IFACE" = "lo" ]; then
-  printf "Error: Network interface '%s' is not available.\n" "$NET_IFACE" >&2
-  if [ -z "$VPN_NET_IFACE" ]; then
-cat 1>&2 <<EOF
-Could not detect the default network interface. Re-run this script with:
-  sudo VPN_NET_IFACE="default_interface_name" sh "$0"
-EOF
+else
+  eth0_state=$(cat "/sys/class/net/eth0/operstate" 2>/dev/null)
+  if [ -z "$eth0_state" ] || [ "$eth0_state" = "down" ]; then
+    exiterr "Could not detect the default network interface."
   fi
-  exit 1
+  NET_IFACE=eth0
 fi
 
 [ -n "$YOUR_IPSEC_PSK" ] && VPN_IPSEC_PSK="$YOUR_IPSEC_PSK"
diff --git a/vpnsetup_centos.sh b/vpnsetup_centos.sh
index 93967c9..c133bc4 100755
--- a/vpnsetup_centos.sh
+++ b/vpnsetup_centos.sh
@@ -60,10 +60,8 @@ if [ "$(id -u)" != 0 ]; then
   exiterr "Script must be run as root. Try 'sudo sh $0'"
 fi
 
-NET_IFACE=${VPN_NET_IFACE:-'eth0'}
-def_iface="$(route 2>/dev/null | grep '^default' | grep -o '[^ ]*$')"
-[ -z "$def_iface" ] && def_iface="$(ip -4 route list 0/0 2>/dev/null | grep -Po '(?<=dev )(\S+)')"
-
+def_iface=$(route 2>/dev/null | grep '^default' | grep -o '[^ ]*$')
+[ -z "$def_iface" ] && def_iface=$(ip -4 route list 0/0 2>/dev/null | grep -Po '(?<=dev )(\S+)')
 def_state=$(cat "/sys/class/net/$def_iface/operstate" 2>/dev/null)
 if [ -n "$def_state" ] && [ "$def_state" != "down" ]; then
   case "$def_iface" in
@@ -72,18 +70,12 @@ if [ -n "$def_state" ] && [ "$def_state" != "down" ]; then
       ;;
   esac
   NET_IFACE="$def_iface"
-fi
-
-net_state=$(cat "/sys/class/net/$NET_IFACE/operstate" 2>/dev/null)
-if [ -z "$net_state" ] || [ "$net_state" = "down" ] || [ "$NET_IFACE" = "lo" ]; then
-  printf "Error: Network interface '%s' is not available.\n" "$NET_IFACE" >&2
-  if [ -z "$VPN_NET_IFACE" ]; then
-cat 1>&2 <<EOF
-Could not detect the default network interface. Re-run this script with:
-  sudo VPN_NET_IFACE="default_interface_name" sh "$0"
-EOF
+else
+  eth0_state=$(cat "/sys/class/net/eth0/operstate" 2>/dev/null)
+  if [ -z "$eth0_state" ] || [ "$eth0_state" = "down" ]; then
+    exiterr "Could not detect the default network interface."
   fi
-  exit 1
+  NET_IFACE=eth0
 fi
 
 [ -n "$YOUR_IPSEC_PSK" ] && VPN_IPSEC_PSK="$YOUR_IPSEC_PSK"