#!/usr/bin/env python
# Copyright (c) 2014, Joseph Hunkeler <jhunkeler at gmail.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice,
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

class ExitCode(object):
    SUCCESS, FAIL, NO_MODULE, NO_INTERFACE = range(4)

try:
    import argparse
except ImportError:
    print('argparse module required.')
    exit(ExitCode.NO_MODULE)

try:
    import netifaces
except ImportError:
    print('netifaces module required.')
    exit(ExitCode.NO_MODULE)

try:
    from netaddr import IPNetwork
except ImportError:
    print('netaddr module required.')
    exit(ExitCode.NO_MODULE)


DEBUG = False
VERBOSE = False

def info(ignore, accept):
    status = {'IGNORED':[], 'DETECTED':[], 'OTHER':[]}
    for interface in netifaces.interfaces():
        ignored = False
        detected = False

        try:
            addr = netifaces.ifaddresses(interface)
            if not netifaces.AF_INET in addr:
                continue
        except:
            return None

        for iface in addr[netifaces.AF_INET]:
            if not 'addr' in iface:
                continue

            address = iface['addr']
            for ip_range in ignore:
                if address in ip_range:
                    ignored = True

            for ip_range in accept:
                if address in ip_range:
                    detected = True

            if ignored:
                if DEBUG:
                    print('Ignored: {0} on {1}'.format(address, interface))
                status['IGNORED'].append(address)
                continue

            if detected:
                if DEBUG:
                    print('Detected: {0} on {1}'.format(address, interface))
                status['DETECTED'].append(address)
                continue
            
            if DEBUG:
                print('Detected (non-match): {0} on {1}'.format(address, interface))
            status['OTHER'].append(address)
    return status

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Detects whether or not any ethernet devices match to a defined CIDR range.')
    parser.add_argument('--ignore', '-i', action='append', default=[ IPNetwork('127.0.0.0/8'), IPNetwork('169.254.0.0/16') ], type=IPNetwork, help='IP range(s) to ignore (Default: link-local and localhost)')
    parser.add_argument('--debug', '-d', action='store_true', default=False)
    parser.add_argument('--verbose', '-v', action='store_true', default=False)
    parser.add_argument('cidr', nargs="+", type=IPNetwork, help='IP range(s) to detect')
    args = parser.parse_args()
    
    DEBUG = args.debug
    VERBOSE = args.verbose

    status = info(args.ignore, args.cidr)

    if status is None:
        if DEBUG:
            print("No ethernet interface detected")
        if VERBOSE:
            print(ExitCode.NO_INTERFACE)
        exit(ExitCode.NO_INTERFACE)

    if not status['DETECTED']:
        if DEBUG:
            print("No ethernet interface is operating at the defined range")
        if VERBOSE:
            print(ExitCode.FAIL)
        exit(ExitCode.FAIL)

    if DEBUG:
        print("A network interface matched defined range")
    if VERBOSE:
        print(ExitCode.SUCCESS)

    exit(ExitCode.SUCCESS)