Convert one or more BGP Autonomous System Number (ASN) to a list of corresponding IPv4 networks, updated to work with python3.

asn-to-ip.py

import socket
import re

## https://tools.ietf.org/html/rfc3912
def whois_request(domain, server, port=43):
    _sock=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    _sock.connect((server, port))
    _sock.send(domain.encode('utf-8'))
    _result=""
    while True:
        _data=_sock.recv(1024).decode('iso-8859-1')
        if not _data:
            break
        _result += _data
    return _result

def get_AS(AS,IPV4=True,IPV6=True):
    ## sanitize ASN
    _asn=re.search("(?:AS)?(\d{1,10})",AS,re.IGNORECASE)
    if not _asn:
        return ""
    _asn="AS{0}".format(_asn.group(1))
    is6=""
    if IPV6:
        is6="[6]?" if IPV4 else "6"
    _raw=whois_request("-i origin {0}\r\n".format(_asn),"whois.radb.net")
    if _raw:
        _ips=re.findall("^route{0}:\s+(.*?)$".format(is6),_raw,re.MULTILINE)
        return "\n".join(_ips)
    return ""

if __name__ == "__main__":
    import sys
    if len(sys.argv) > 1:
      for i in range(1,len(sys.argv)):
        AS=sys.argv[i]
        print(get_AS(AS,IPV6=False))
    else:
      print("Takes as input one or more BGP ASNs, returns a list of IPV4 networks for those ASNs.\n\nUsage:", sys.argv[0], "as32934\n")