#!/usr/bin/env python

#
# Do a traceroute using a looking glass server
# Brian Landers <brian@packetslave.com>
#
# $Id: lgtrace.txt,v 1.1 2002/11/17 05:17:02 blanders Exp $
#

import telnetlib
import sys

#
# NOTE:  please be polite.  AT&T kindly provides a publically-available
#        router open to telnet.  Don't hammer it with the script or they
#        might reconsider their generosity.
#
#        Needless to say, I'm not responsible for any trouble you might
#        get into by using this script.  AT&T doesn't seem to have any
#        terms of service on the router's MOTD precluding scripts like
#        this, but just in case, you use this script solely at your own
#        risk.
#

kSERVER   = 'route-server.ip.att.net'
kPROMPT   = 'route-server>'
kTIMEOUT  = 15

# Get the IP or hostname to telnet to
if len( sys.argv ) != 2:
    sys.err.write( "usage: lgtrace <destination>\n" );
    sys.exit(1)

print "Connecting to server %s..." % kSERVER
tn = telnetlib.Telnet( kSERVER )

print "Waiting for router prompt..."
tn.read_until( kPROMPT, kTIMEOUT )

print "Sending command..."
tn.write( "trace " + sys.argv[1] + "\n" )

print "Here's the output..."

# Skip ahead in the output to the actual trace
# FIXME: handle errors
line = tn.expect( ["Tracing the route.+\n"], kTIMEOUT )

# List of RE's to match against
xp = [ "\n", kPROMPT ]

# Read the first line of the trace
line = tn.expect( xp, kTIMEOUT )
while line:
    # If we matched the prompt, we're done
    if line[0] == 1:
        break

    # Write the current line and read again
    sys.stdout.write( line[2] )
    sys.stdout.flush()
    line = tn.expect( xp, kTIMEOUT )

# Close the telnet connection
tn.close()