#!/usr/bin/env python3 # Copyright (c) 2022 Pieter Wuille # Distributed under the MIT software license, see the accompanying # file LICENSE or http://www.opensource.org/licenses/mit-license.php. import argparse import sys import ipaddress import math import asmap def load_file(input_file): try: contents = input_file.read() except OSError as err: sys.exit(f"Input file '{input_file.name}' cannot be read: {err.strerror}.") try: bin_asmap = asmap.ASMap.from_binary(contents) except ValueError: bin_asmap = None txt_error = None entries = None try: txt_contents = str(contents, encoding="utf-8") except UnicodeError: txt_error = "invalid UTF-8" txt_contents = None if txt_contents is not None: entries = [] for line in txt_contents.split("\n"): idx = line.find('#') if idx >= 0: line = line[:idx] line = line.lstrip(' ').rstrip(' \t\r\n') if len(line) == 0: continue fields = line.split(' ') if len(fields) != 2: txt_error = f"unparseable line '{line}'" entries = None break prefix, asn = fields if len(asn) <= 2 or asn[:2] != "AS" or any(c < '0' or c > '9' for c in asn[2:]): txt_error = f"invalid ASN '{asn}'" entries = None break try: net = ipaddress.ip_network(prefix) except ValueError: txt_error = f"invalid network '{prefix}'" entries = None break entries.append((asmap.net_to_prefix(net), int(asn[2:]))) if entries is not None and bin_asmap is not None and len(contents) > 0: sys.exit(f"Input file '{input_file.name}' is ambiguous.") if entries is not None: state = asmap.ASMap() state.update_multi(entries) return state if bin_asmap is not None: return bin_asmap sys.exit(f"Input file '{input_file.name}' is neither a valid binary asmap file nor valid text input ({txt_error}).") def save_binary(output_file, state, fill): contents = state.to_binary(fill=fill) try: output_file.write(contents) output_file.close() except OSError as err: sys.exit(f"Output file '{output_file.name}' cannot be written to: {err.strerror}.") def save_text(output_file, state, fill, overlapping): for prefix, asn in state.to_entries(fill=fill, overlapping=overlapping): net = asmap.prefix_to_net(prefix) try: print(f"{net} AS{asn}", file=output_file) except OSError as err: sys.exit(f"Output file '{output_file.name}' cannot be written to: {err.strerror}.") try: output_file.close() except OSError as err: sys.exit(f"Output file '{output_file.name}' cannot be written to: {err.strerror}.") def main(): parser = argparse.ArgumentParser(description="Tool for performing various operations on textual and binary asmap files.") subparsers = parser.add_subparsers(title="valid subcommands", dest="subcommand") parser_encode = subparsers.add_parser("encode", help="convert asmap data to binary format") parser_encode.add_argument('-f', '--fill', dest="fill", default=False, action="store_true", help="permit reassigning undefined network ranges arbitrarily to reduce size") parser_encode.add_argument('infile', nargs='?', type=argparse.FileType('rb'), default=sys.stdin.buffer, help="input asmap file (text or binary); default is stdin") parser_encode.add_argument('outfile', nargs='?', type=argparse.FileType('wb'), default=sys.stdout.buffer, help="output binary asmap file; default is stdout") parser_decode = subparsers.add_parser("decode", help="convert asmap data to text format") parser_decode.add_argument('-f', '--fill', dest="fill", default=False, action="store_true", help="permit reassigning undefined network ranges arbitrarily to reduce length") parser_decode.add_argument('-n', '--nonoverlapping', dest="overlapping", default=True, action="store_false", help="output strictly non-overall ping network ranges (increases output size)") parser_decode.add_argument('infile', nargs='?', type=argparse.FileType('rb'), default=sys.stdin.buffer, help="input asmap file (text or binary); default is stdin") parser_decode.add_argument('outfile', nargs='?', type=argparse.FileType('w'), default=sys.stdout, help="output text file; default is stdout") parser_diff = subparsers.add_parser("diff", help="compute the difference between two asmap files") parser_diff.add_argument('-i', '--ignore-unassigned', dest="ignore_unassigned", default=False, action="store_true", help="ignore unassigned ranges in the first input (useful when second input is filled)") parser_diff.add_argument('infile1', type=argparse.FileType('rb'), help="first file to compare (text or binary)") parser_diff.add_argument('infile2', type=argparse.FileType('rb'), help="second file to compare (text or binary)") args = parser.parse_args() if args.subcommand is None: parser.print_help() elif args.subcommand == "encode": state = load_file(args.infile) save_binary(args.outfile, state, fill=args.fill) elif args.subcommand == "decode": state = load_file(args.infile) save_text(args.outfile, state, fill=args.fill, overlapping=args.overlapping) elif args.subcommand == "diff": state1 = load_file(args.infile1) state2 = load_file(args.infile2) ipv4_changed = 0 ipv6_changed = 0 for prefix, old_asn, new_asn in state1.diff(state2): if args.ignore_unassigned and old_asn == 0: continue net = asmap.prefix_to_net(prefix) if isinstance(net, ipaddress.IPv4Network): ipv4_changed += 1 << (32 - net.prefixlen) elif isinstance(net, ipaddress.IPv6Network): ipv6_changed += 1 << (128 - net.prefixlen) if new_asn == 0: print(f"# {net} was AS{old_asn}") elif old_asn == 0: print(f"{net} AS{new_asn} # was unassigned") else: print(f"{net} AS{new_asn} # was AS{old_asn}") ipv4_change_str = "" if ipv4_changed == 0 else f" (2^{math.log2(ipv4_changed):.2f})" ipv6_change_str = "" if ipv6_changed == 0 else f" (2^{math.log2(ipv6_changed):.2f})" print( f"# {ipv4_changed}{ipv4_change_str} IPv4 addresses changed; " f"{ipv6_changed}{ipv6_change_str} IPv6 addresses changed" ) else: parser.print_help() sys.exit("No command provided.") if __name__ == '__main__': main()