mkroa

#!/usr/bin/env python3

from textwrap import dedent
from argparse import ArgumentParser
from formatter import Formatter
from filereader import get_communities_data


class BirdRoaFormatter(Formatter):
    """
    Formatter for roa table in bird format
    """

    def __init__(self, roa_table_name=False):
        self.config = []
        self.data = []
        self.indent = ""
        self.roa_table_name = roa_table_name

        if not roa_table_name:
            self.add_comment(dedent(
                """
                This file is automatically generated.
                You need to add the surrounding roa table statement yourself.
                So Include it via:
                  roa table icvpn { include "roa.con?" }
                """
            ))
        else:
            self.indent = "\t"
            self.config.append("roa table {tbl_name} {{".format(
                tbl_name=roa_table_name
            ))

    def add_data(self, asn, name, network, max_prefixlen):
        self.data.append((network, max_prefixlen, asn, name))

    def finalize(self):
        maxlen_net = str(max(map(lambda x: len(x[0]), self.data)))
        maxlen_asn = str(max(map(lambda x: len(str(x[2])), self.data)))

        for entry in self.data:
            self.config.append(
                "{indent}roa {subnet:<{len_net}} max {max_prefix_len:>3} as {asn:>{len_asn}}; # {community}".format(
                    indent=self.indent, subnet=entry[0], max_prefix_len=entry[1], asn=entry[2],
                    community=entry[3], len_net=maxlen_net, len_asn=maxlen_asn
                ))

        if self.roa_table_name:
            self.config.append("}")

        return "\n".join(self.config)


def add_roa(formatter, asn, community, network, prefixlen, default_max_prefixlen):
    formatter.add_data(asn, community, network, max(prefixlen, default_max_prefixlen))


def create_config(srcdir, exclude, family, fmtclass, default_max_prefixlen, *args):
    """
    Generates a configuration using all files in srcdir
    (non-recursively) excluding communities from 'exclude'.

    The files are read in lexicographic order to produce deterministic
    results.
    """
    formatter = fmtclass(*args)

    if default_max_prefixlen is None:
        if family == 'ipv6':
            default_max_prefixlen = 64
        elif family == 'ipv4':
            default_max_prefixlen = 24

    for community, data in get_communities_data(srcdir, exclude):
        try:
            networks = data['networks'][family]
            asn = data['asn']
            for network in sorted(networks):
                prefixlen = int(network.split("/")[1])
                add_roa(formatter, asn, community, network, prefixlen, default_max_prefixlen)
        except (TypeError, KeyError):
            pass

        delegate = data.get('delegate', {})
        for delegate_asn, delegate_networks in delegate.items():
            for delegate_network in delegate_networks:
                # not very beautiful, but everything more proper requires including a library
                if family == 'ipv6' and '.' in delegate_network:
                    continue
                if family == 'ipv4' and ':' in delegate_network:
                    continue
                prefixlen = int(delegate_network.split("/")[1])
                add_roa(formatter, delegate_asn, "{} (delegation)".format(community), delegate_network, prefixlen,
                        default_max_prefixlen)

    print(formatter.finalize())


if __name__ == '__main__':
    formatters = {
        'bird': BirdRoaFormatter,
    }

    PARSER = ArgumentParser()
    PARSER.add_argument('-f', '--format', dest='fmt',
                        help='Create config in format FMT. Possible values: {formatters}.'.format(
                            formatters=", ".join(formatters.keys())),
                        metavar='FMT',
                        choices=list(formatters.keys()),
                        default='bird')
    PARSER.add_argument('-4', dest='family', action='store_const', const='ipv4',
                        help='Generate IPv4 config')
    PARSER.add_argument('-6', dest='family', action='store_const', const='ipv6',
                        help='Generate IPv6 config')
    PARSER.add_argument('-s', '--sourcedir', dest='src',
                        help="Use files in DIR as input files. Default: ../icvpn-meta/",
                        metavar="DIR", default="../icvpn-meta/")
    PARSER.add_argument('-x', '--exclude', dest='exclude', action='append',
                        help='Exclude the comma-separated list of COMMUNITIES',
                        metavar='COMMUNITIES',
                        default=[])
    PARSER.add_argument('-m', '--max', dest='default_max_prefixlen', default=None,
                        type=int, help='max prefix length to accept')
    PARSER.add_argument('--bird-table-name', dest='bird_table_name',
                        help='Render ROA table with given name', default=False)
    PARSER.set_defaults(family='ipv6')

    ARGS = PARSER.parse_args()

    create_config(ARGS.src, set(ARGS.exclude),
                  ARGS.family, formatters[ARGS.fmt],
                  ARGS.default_max_prefixlen, ARGS.bird_table_name)