ping-ipv6-up

#!/bin/bash

# this script does not read or change the local interface at all
# its for use with a host behind NAT where the NAT device can do 6rd or 6in4 but can't update the tunnel broker

# as tunnelbroker.net don't want us to brute force their API, we leave the API update until we're sure our IPv4 address has changed

# http://www.linuxjournal.com/content/validating-ip-address-bash-script
function valid_ip()
{
    local  ip=$1
    local  stat=1

    if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
        OIFS=$IFS
        IFS='.'
        ip=($ip)
        IFS=$OIFS
        [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
            && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
        stat=$?
    fi
    return $stat
}

# If run directly, execute some tests.
if [[ "$(basename $0 .sh)" == 'valid_ip' ]]; then
    ips='
        4.2.2.2
        a.b.c.d
        192.168.1.1
        0.0.0.0
        255.255.255.255
        255.255.255.256
        192.168.0.1
        192.168.0
        1234.123.123.123
        '
    for ip in $ips
    do
        if valid_ip $ip; then stat='good'; else stat='bad'; fi
        printf "%-20s: %s\n" "$ip" "$stat"
    done
fi

read_dom () {
    local IFS=\>
    read -d \< ENTITY CONTENT
}




#HE_USER should be in ENV
#HE_PASS should be in ENV
#HE_TUNNEL should be in ENV
HE_PASS_ENC=`perl -MURI::Escape -e "print uri_escape('$HE_PASS')"`
HE_CURRENT_IPV4_FILE="/var/tmp/my_tunnelbroker_values"
HE_CURRENT_IPV4=""


# https://stackoverflow.com/questions/6118948/bash-loop-ping-successful?rq=1
((count = 10))                            # Maximum number to try.
while [[ $count -ne 0 ]] ; do
    # as with good ole 8.8.8.8 we want an IPv6 address and not a hostname
    ping6 -q -c 1 2001:4860:4860::8888 > /dev/null   # Try once.
    rc=$?
    if [[ $rc -eq 0 ]] ; then
        ((count = 1))                      # If okay, flag to exit loop.
    fi
    ((count = count - 1))                  # So we don't go forever.
done

if [[ $rc -eq 0 ]] ; then                  # Make final determination.
    echo "ipv6 is up"
	# only run if ipv6 appears down	
	exit 0
else
    echo `say IPv6 timed out.`
fi


# update / make sure we have the he.net current tunnelbroker values (XML output)
curl -k -s -o $HE_CURRENT_IPV4_FILE "https://$HE_USER:$HE_PASS_ENC@tunnelbroker.net/tunnelInfo.php?tid=$HE_TUNNEL" 

# https://stackoverflow.com/questions/893585/how-to-parse-xml-in-bash
while read_dom; do
    if [[ $ENTITY = "clientv4" ]]; then
		if valid_ip $CONTENT; then
        	echo "he.net IPV4 is $CONTENT"
			HE_CURRENT_IPV4="$CONTENT"
		fi
        #exit
    fi
done < $HE_CURRENT_IPV4_FILE

# this could be more sophisticated with a list to walk through if one fails
MY_CURRENT_IPV4=`curl -s "http://ipv4.whatsmyip.reliable-ict.de/"`


if [[ "$MY_CURRENT_IPV4" == "$HE_CURRENT_IPV4" ]]; then
	echo "ips are the same"
else
	echo "not matched so updating tunnelbroker"
	curl -k -s "https://ipv4.tunnelbroker.net/nic/update?username=$HE_USER&password=$HE_PASS&hostname=$HE_TUNNEL"
	#sleep 1
	#echo "External IPv6:`curl -s 'http://ipv6.whatsmyip.reliable-ict.de/'`."
	#echo "External IPv4:`curl -s 'http://whatsmyip.reliable-ict.de/'`."	
fi



# TODO Launch shell script on login in Mac OS (OS X) http://stackoverflow.com/questions/22842016/launch-shell-script-on-login-in-mac-os-os-x



# current data is available with
# curl -k -s "https://$HE_USER:$HE_PASS_ENC@tunnelbroker.net/tunnelInfo.php?tid=$HE_TUNNEL"

# returns

# <?xml version="1.0" encoding="UTF-8"?>
# <tunnels>
#  <tunnel id="{tunnel_id}>
#   <description></description>
#   <serverv4>{Server IPv4 Address}</serverv4>
#   <clientv4>{Client IPv4 Address}</clientv4>
#   <serverv6>{Server IPv6 Address}</serverv6>
#   <clientv6>{Client IPv6 Address}</clientv6>
#   <routed64>{Routed /64}</routed64>
#  </tunnel>
# </tunnels>