#!/usr/bin/env python2
#
# Copyright (c) 2017-2019  Joe Clarke <jclarke@cisco.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 AUTHOR 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 AUTHOR 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.

import paramiko
import os
from sparker import Sparker
import time
from subprocess import Popen, PIPE
import shlex
import re
import json
import CLEUCreds

routers = {}

commands = {
    'ip_route': 'show ip route',
    'ipv6_route': 'show ipv6 route'
}

cache_dir = '/home/jclarke/routing-tables'
ROUTER_FILE = '/home/jclarke/routers.json'

SPARK_TEAM = 'CL19 NOC Team'
SPARK_ROOM = 'Core Alarms'

if __name__ == '__main__':
    spark = Sparker(token=CLEUCreds.SPARK_TOKEN)
    ssh_client = paramiko.SSHClient()
    ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())

    try:
        fd = open(ROUTER_FILE, 'r')
        routers = json.load(fd)
        fd.close()
    except:
        pass

    for router, ip in routers.items():
        try:
            ssh_client.connect(ip, username=CLEUCreds.NET_USER, password=CLEUCreds.NET_PASS,
                               timeout=60, allow_agent=False, look_for_keys=False)
            chan = ssh_client.invoke_shell()
            for fname, command in commands.items():
                output = ''
                try:
                    chan.sendall("term length 0\n")
                    chan.sendall("term width 0\n")
                    chan.sendall("{}\n".format(command))
                    i = 0
                    while i < 10:
                        if chan.recv_ready():
                            break
                        time.sleep(.5)
                        i += 1
                    while chan.recv_ready():
                        output = output + chan.recv(65535)
                except Exception as ie:
                    print('Failed to get {} from {}: {}'.format(
                        command, router, ie))
                    continue

                fpath = '{}/{}-{}'.format(cache_dir, fname, router)
                curr_path = fpath + '.curr'
                prev_path = fpath + '.prev'
                fd = open(curr_path, 'w')
                output = re.sub(r'\r', '', output)
                output = re.sub(r'([\d\.]+) (\[[^\n]+)',
                                '\\1\n          \\2', output)
                fd.write(
                    re.sub(r'(via [\d\.]+), [^,\n]+([,\n])', '\\1\\2', output))
                fd.close()

                if os.path.exists(prev_path):
                    proc = Popen(
                        shlex.split('/usr/bin/diff -E -b -B -w -u {} {}'.format(prev_path, curr_path)), stdout=PIPE, stderr=PIPE)
                    out, err = proc.communicate()
                    rc = proc.returncode

                    if rc != 0:
                        spark.post_to_spark(
                            SPARK_TEAM, SPARK_ROOM, '**ALERT**: Routing table diff ({}) on **{}**:\n```\n{}\n```'.format(command, router, re.sub(cache_dir + '/', '', out)))
                        time.sleep(1)
                        #print('XXX: Out = \'{}\''.format(out))

                os.rename(curr_path, prev_path)

        except Exception as e:
            ssh_client.close()
            print('Failed to get routing tables from {}: {}'.format(router, e))
            continue

        ssh_client.close()