#!/usr/bin/python
"""

SIP Ping - A diagnostic utility for critical VoIP monitoring
Created by Gravis
Version 1.0

==========================================================================

Software License:
Do whatever you want with this code. There are no restrictions.

Not-license:
I'd like to hear back from you if you do something interesting with this.

==========================================================================

SIP Ping is a tool for monitoring a SIP gateway (PBX, SBC, phone) for deep
dive diagnostics. Most tools for VoIP monitoring are based on meeting SLA
figures and providing general "network availability" statistics. SIP Ping
is for granular troubleshooting.

See http://gekk.info/sipping for more information and suggested usage.
Commandline flags and defaults are available by running "python sipping.py -h"

"""

from hashlib import md5
import random
import re
import cgi
import cgitb
import sys
import os
import socket
import json
import urllib

# handler for ctrl+c / SIGINT
# last action before quitting is to write a \n to the end of the output file
import signal
def signal_handler(signal, frame):
        print('\nCtrl+C - exiting.')
	if v_logpath != "*":
		f_log = open(v_logpath, "a")
                f_log.write('\n')
                f_log.close()
	printstats()
	sys.exit(0)

def printstats():
	# loss stats
        print ("\t[Recd: {recd} | Lost: {lost}]".format(recd=v_recd,lost=v_lost)),

        if v_longest_run > 0:
        	print ("\t[loss stats:"),
        	print ("longest run: " + str(v_longest_run)),
        if v_last_run_loss > 0:
                print (" length of last run: " + str(v_last_run_loss)),
        if v_current_run_loss > 0:
                print (" length of current run: " + str(v_current_run_loss)),
        print ("]")

        # min max avg
        v_total = 0;
        for i in l_history:
                v_total = v_total + i
	if v_total > 0:
        	v_avg = v_total / len(l_history)
	else:
		v_avg = 0
        print ("\t[min/max/avg {min}/{max}/{avg}]".format(min=v_min,max=v_max,avg=v_avg))

# create and execute command line parser
import argparse
parser = argparse.ArgumentParser(description="Send SIP OPTIONS messages to a host and measure response time. Results are logged continuously to CSV.")
parser.add_argument("host", help="Target SIP device to ping")
parser.add_argument("-I", metavar="interval", default=1000, help="Interval in milliseconds between pings (default 1000)")
parser.add_argument("-u", metavar="userid", default="sipping", help="User part of the From header (default sipping)")
parser.add_argument("-i", metavar="ip", default="*", help="IP to send in the Via header (will TRY to get local IP by default)")
parser.add_argument("-d", metavar="domain", default="gekk.info", help="Domain part of the From header (needed if your device filters based on domain)")
parser.add_argument("-p", metavar="port", default=5060, help="Destination port (default 5060)")
parser.add_argument("--ttl", metavar="ttl", default=70, help="Value to use for the Max-Forwards field (default 70)")
parser.add_argument("-w", metavar="file", default="[[default]]", help="File to write results to. (default sipping-logs/[ip] - * to disable.")
parser.add_argument("-t", metavar="timeout", default="1000", help="Time (ms) to wait for response (default 1000)")
parser.add_argument("-c", metavar="count", default="0", help="Number of pings to send (default infinite)")
parser.add_argument("-x", nargs="?", default=False, help="Print raw transmitted packets")
parser.add_argument("-X", nargs="?", default=False, help="Print raw received responses")
parser.add_argument("-q", nargs="?", default=True, help="Do not print status messages (-x and -X ignore this)")
parser.add_argument("-S", nargs="?", default=True, help="Do not print loss statistics")
args = vars(parser.parse_args())

# populate data from commandline
# anything unspecified on the commandline is set to a default value by the parser
v_interval = int(args["I"])
v_fromip = args["i"]
v_sbc = args["host"]
# did the user enter an IP?
if re.match("\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}", v_sbc) is None:
	# the user entered a hostname; resolve it
	try:
		v_sbc = socket.getaddrinfo(v_sbc, 5060)[0][4][0]
	# socket.gaierror catches socket-specific exceptions but I think we can go without
	#except socket.gaierror as error:
	except Exception as error:
		# dns failure or no response
		print error.strerror
		sys.exit(1)

v_userid = args["u"]
v_port = int(args["p"])
v_domain = args["d"]
v_ttl = args["ttl"]
v_timeout = int(args["t"])
v_rawsend = args["x"] == None
v_rawrecv = args["X"] == None
v_quiet = not args["q"]
v_nostats = not args["S"]
if args["w"] == "[[default]]":
	if not os.path.exists("sipping-logs"): os.mkdir("sipping-logs")
	v_logpath = "sipping-logs/{ip}.csv".format(ip=v_sbc)
else:
	v_logpath = args["w"]

# if log output is enabled, ensure CSV has header
if v_logpath != "*":
	if not os.path.isfile(v_logpath):
		# create new CSV file and write header
		f_log = open(v_logpath, "w")
		f_log.write("time,timestamp,host,latency,callid,response")
		f_log.close()

def generate_nonce(length=8):
    """Generate pseudorandom number for call IDs."""
    return ''.join([str(random.randint(0, 9)) for i in range(length)])

# writes onscreen timestamps in a consistent format
from datetime import datetime
import time
def timef(timev=None):
        if timev == None:
                return datetime.now().strftime("%d/%m/%y %I:%M:%S:%f")
        else:
                return datetime.fromtimestamp(timev)

# register signal handler for ctrl+c since we're ready to start
signal.signal(signal.SIGINT, signal_handler)
if not v_quiet: print("Press Ctrl+C to abort");

# zero out statistics variables
v_recd = 0
v_lost = 0
v_longest_run = 0
v_last_run_loss = 0
v_current_run_loss = 0
last_lost = "never"
l_history = []
v_min = float("inf");
v_max = float("-inf");
v_iter = 0

# empty list of last 5 pings
l_current_results = []

# start the ping loop
while 1:
	# create a socket
	skt_sbc = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
	skt_sbc.bind(("0.0.0.0", 0))
	skt_sbc.settimeout(v_timeout / 1000.0)
	# find out what port we're transmitting from to correlate the return packet
	v_localport = skt_sbc.getsockname()[1]
	# find out what IP we're sourcing from to populate the Via
	if v_fromip != "*":
		v_lanip = v_fromip
	else:
		v_lanip = socket.gethostbyname(socket.gethostname()) 

	# latency is calculated from this timestamp
	start = time.time()
	
	# create a random callid so we can identify the message in a packet capture
	v_callid = generate_nonce(length=10)

	# write the OPTIONS packet
	v_register_one = """OPTIONS sip:{domain} SIP/2.0
Via: SIP/2.0/UDP {lanip}:{localport}
To: "SIP Ping"<sip:{userid}@{domain}>
From: "SIP Ping"<sip:{userid}@{domain}>
Call-ID: {callid}
CSeq: 1 OPTIONS
Max-forwards: {ttl}
X-redundancy: Request
Content-Length: 0

""".format(domain=v_domain, lanip=v_lanip, userid=v_userid, localport=v_localport, callid=v_callid, ttl=v_ttl)
	
	# print transmit announcement
	if not v_quiet: print ("> ({time}) Sending to {host}:{port} [id: {id}]".format(host=v_sbc,port=v_port, time=timef(), id=v_callid))

	# if -x was passed, print the transmitted packet
	if v_rawsend:
		print (v_register_one)	

	# send the packet
	skt_sbc.sendto(v_register_one, (v_sbc, v_port))

	start = time.time()
	# wait for response
	try:
		# start a synchronous receive
		data, addr = skt_sbc.recvfrom(1024) # buffer size is 1024 bytes

		# latency is calculated against this time		
		end = time.time()
		diff = float("%.2f" % ((end - start) * 1000.0))
		
		# pick out the first line in order to get the SIP response code
		v_response = data.split("\n")[0]
		
		# print success message and response code
		if not v_quiet: print("< ({time}) Reply from {host} ({diff}ms): {response}".format(host=addr[0], diff=diff, time=timef(), response=v_response))

	        # if -X was passed, print the received packet
        	if v_rawrecv:
	                print (data)


		# log success
		l_current_results.append("{time},{timestamp},{host},{diff},{id},{response}".format(host=addr[0], diff=diff, time=timef(), timestamp=time.time(), id=v_callid, response=v_response))

		# update statistics
		l_history.append(diff)
		if len(l_history) > 200:
			l_history = l_history[1:]
		if diff < v_min:
			v_min = diff
		if diff > v_max:
			v_max = diff;
		v_recd = v_recd + 1
		if v_current_run_loss > 0:
			v_last_run_loss = v_current_run_loss
			if v_last_run_loss > v_longest_run:
				v_longest_run = v_last_run_loss
			v_current_run_loss = 0
	except socket.timeout:
		# timed out; print a drop
		if not v_quiet: print ("X ({time}) Timed out waiting for response from {host}".format(host=v_sbc, time=timef()))
		# log a drop
		l_current_results.append("{time},{timestamp},{host},drop,{id},drop".format(host=v_sbc, time=timef(), timestamp=time.time(), id=v_callid))
		
		# increment statistics
		v_lost = v_lost + 1
		v_current_run_loss = v_current_run_loss + 1
	
	v_iter = v_iter + 1
	# if it's been five packets, print stats and write logfile
	if v_iter > 4:
		# print stats to screen
		if not v_nostats:
			printstats()
		
		# if logging is enabled, append stats to logfile
		if v_logpath != "*":
			f_log = open(v_logpath, "a")
			f_log.write("\n" + ("\n".join(l_current_results)))
			f_log.close()
		l_current_results = []

		v_iter = 0
	
	# pause for user-requested interval before sending next packet
	time.sleep(v_interval / 1000.0)