Make the IPv4 validation regex more permissive as per Marco Wessel's suggestion (closes #5)

Make some cosmetic fixes just because I'm here.

Author: dmbaturin

etc/init.d/rcS

@@ -4,7 +4,7 @@
 #
 # Maintainer: Daniil Baturin <daniil at baturin dot org>
 #
-# Copyright (C) 2013 SO3Group
+# Copyright (C) 2013, 2017 Daniil Baturin and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
@@ -25,7 +25,7 @@
 # Value is chosen rather arbitrary
 sleep 10
 echo
-echo "Loading EMRK 0.9a"
+echo "Loading EMRK 0.9d"
 
 echo "Mounting filesystems"
 mount -a
@@ -167,8 +167,6 @@ echo
 echo "This tool is distributed under the terms of"
 echo "GNU General Public License and other licenses"
 echo
-echo "Brought to you by SO3 Group"
-echo
 echo "WARNING: This tool is not developed, officially"
 echo "supported or endorsed by Ubiquiti Networks!"
 echo
@@ -209,7 +207,7 @@ if [ $? == 0 ]; then
         DHCP_OK=1
         NET_OK=1
     else
-        echo "DHCP configuration attemp failes!"
+        echo "DHCP configuration attemp failed!"
     fi
 fi
 
@@ -247,8 +245,9 @@ if [ $DHCP_OK != 1 ]; then
        # Set DNS server
         while true; do
             read -p "Enter DNS server address: " DNS
-            # XXX: this regex sucks
-            echo $DNS | grep -E "[1-2][0-9]{,2}\.(0|[0-9]{1,3})\.(0|[0-9]{1,3})\.([0-9]{1,3})" > /dev/null
+            # XXX: overly permissive regex to protect just against
+            #      obvious typos
+            echo $DNS | grep -E "[0-9.]+" > /dev/null
             if [ $? == 0 ]; then
                 echo "nameserver $DNS" > /etc/resolv.conf
                 break