#!/bin/bash

# Generate voipgrid-ips.conf
# Modify to suit your needs

# Hosts, one per line
HOSTS="sip.freedom.nl
sip-tls.freedom.nl
sipproxy.voipgrid.nl
sip.encryptedsip.com"
# Output file name
FILE="voipgrid-ips.conf"
# VOIP Provider name
VOIPISP="freedom"
# VOIP Template name
VOIPTPL="voipgrid-in"


IP4S=""
IP6S=""
IPS=""
SRVS=""

export LC_ALL=C.UTF-8


# Functions

# Find IPv4 addresses
find4addr()
{
	IP4S=$( host "${1}" | grep "has address" | awk '{print $4}' )
}

# Find IPv6 addresses
find6addr()
{
	IP6S=$( host "${1}" | grep "has IPv6 address" | awk '{print $5}' )
}

# Find SRV record addresses
findsrvadr()
{
	while read SRV
	do
		#echo "Find IP addresses of ${SRV}"
		find4addr "${SRV}"
		if [ -n "${IP4S}" ]
		then
			#echo "${IP4S}"
			IPS=$( echo -e "${IPS}\n${IP4S}" )
		fi
		find6addr "${SRV}"
		if [ -n "${IP6S}" ]
		then
			#echo "${IP6S}"
			IPS=$( echo -e "${IPS}\n${IP6S}" )
		fi
	done <<< "${SRVS}"
}

# Find SRV records
findsrv()
{
	# Note: ${2} is a hostname
	SRVS=""
	SRVS=$( host -t SRV "${1}.${2}" | awk '{print $8}' )
}

# Find all SRV record addresses
findallsrvadr()
{
	# Note: ${1} is a hostname
	#echo "Find SRV records of ${1}"
	findsrv "_sip._udp" "${1}"
	if [ -n "${SRVS}" ]
	then
		# Sort and remove duplicates
		SRVS=$( echo "${SRVS}" | sort -uV )
		#echo -e "Udp-Sip\n${SRVS}"
		# Find addresses
		findsrvadr
	fi
	findsrv "_sip._tcp" "${1}"
	if [ -n "${SRVS}" ]
	then
		SRVS=$( echo "${SRVS}" | sort -uV )
		#echo -e "Tcp-Sip\n${SRVS}"
		findsrvadr
	fi
	findsrv "_sips._tcp" "${1}"
	if [ -n "${SRVS}" ]
	then
		SRVS=$( echo "${SRVS}" | sort -uV )
		#echo -e "Sip-Tls\n${SRVS}"
		findsrvadr
	fi
}

# Find IPv4 and IPv6 addresses
findadr()
{
	# Note: ${1} is a hostname
	#echo "Find IP addresses of ${1}"
	# Find IPv4 addresses
	find4addr "${1}"
	# Find IPv6 addresses
	find6addr "${1}"
	# Merge
	if [ -n "${IP4S}" ]
	then
		#echo "${IP4S}"
		if [ -z "${IPS}" ]
		then
			# First time
			IPS="${IP4S}"
		else
			# Join
			IPS=$( echo -e "${IPS}\n${IP4S}" )
		fi
	fi
	if [ -n "${IP6S}" ]
	then
		#echo "${IP6S}"
		if [ -z "${IPS}" ]
		then
			# First time
			IPS="${IP6S}"
		else
			# Join
			IPS=$( echo -e "${IPS}\n${IP6S}" )
		fi
	fi
}

while read HOST
do
	# Find IP addresses
	findadr "${HOST}"
	# Add IP addresses of SRV records
	findallsrvadr "${HOST}"
done <<< "${HOSTS}"

# Sort and remove duplicates
IPS=$( echo "${IPS}" | sort -uV )
#echo -e "IP Addresses are\n${IPS}"

# Generate file
CNT=1
echo "; Ip addresses used by ${VOIPTPL}" > "${FILE}"
echo "" >> "${FILE}"
while read IP
do
	NUM=$( printf "%X" "${CNT}" )
	echo "[${VOIPISP}_${NUM}](${VOIPTPL})" >> "${FILE}"
	echo "host=${IP}" >> "${FILE}"
	echo "" >> "${FILE}"
	let CNT+=1
done <<< "${IPS}"