get_advertised_routes.py

import paramiko
import re
from time import sleep

# Router connection details (could be read in from file or argparse)
peer = '172.16.2.10'
username = 'admin'
password = 'admin'

def collect_output(shell, command):
    """ Send command, and wait for output, looking for hostname as end
    of message identifier 
    """
    # Send command, but make sure there is a newline at end
    shell.send(command.strip() + '\n')
    sleep(.25)

    output = ''
    while (shell.recv_ready()):
        output += shell.recv(255)

    return output

def extract_hostname(shell):
    """ Extract the router's hostname from the initial response """
    response = collect_output(shell, 'en\nterm length 0\n')
    return re.search('(\\n.+?#)', response).group(0).strip().replace('#', '')

# Connect to the router using Paramiko, setup a shell to send/receive
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
    ssh.connect(peer, 22, username, password, look_for_keys=False)
except (paramiko.transport.socket.error, 
        paramiko.transport.SSHException, 
        paramiko.transport.socket.timeout, 
        paramiko.auth_handler.AuthenticationException):
    print 'Error connecting to SSH on %s.' % peer
shell = ssh.invoke_shell()
shell.settimeout(3)

hostname = extract_hostname(shell)
neighbor_output = collect_output(shell, '\nshow ip bgp summ | b Neigh\n')

# Filter and add only established BGP sessions
peer_ips = []
non_estab_states = 'neighbor|idle|active|Connect|OpenSent|OpenConfirm'
for line in neighbor_output.split('\n'):
    if bool(re.search(non_estab_states, line, re.IGNORECASE)):
        continue
    else:
        ip_regex = r'(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'
        peer_ips.extend(re.findall(ip_regex, line))

# Iterate through established peers and check advertised routes
for peer in peer_ips:                                                                                                   
    print 'Peer %s:' % peer                                                                                             
                                                                                                                        
    adv_output = collect_output(shell, '\nshow ip bgp neig %s advertised\n' % peer)                                                                                    
    
    # Parse out prefixes in advertised routes                                                                                                                    
    prefix_regex = r'(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/\d{1,2})'
    for prefix in re.findall(prefix_regex, adv_output):                               
        print '\t%s' % prefix                                                                                           
                                                                                                                        
ssh.close()