fwdfirst/ans3/ans.py

"""
Copyright (C) Internet Systems Consortium, Inc. ("ISC")

SPDX-License-Identifier: MPL-2.0

This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0.  If a copy of the MPL was not distributed with this
file, you can obtain one at https://mozilla.org/MPL/2.0/.

See the COPYRIGHT file distributed with this work for additional
information regarding copyright ownership.
"""

from collections.abc import AsyncGenerator

import dns.rcode
import dns.rdatatype
import dns.rrset

from isctest.asyncserver import (
    AsyncDnsServer,
    DnsResponseSend,
    QueryContext,
    ResponseAction,
    ResponseHandler,
)


class AttackerAuthority(ResponseHandler):
    async def get_responses(
        self, qctx: QueryContext
    ) -> AsyncGenerator[ResponseAction, None]:
        if qctx.qtype == dns.rdatatype.A:
            qctx.response.answer.append(
                dns.rrset.from_text(
                    qctx.qname, 300, qctx.qclass, dns.rdatatype.A, "6.6.6.6"
                )
            )

        yield DnsResponseSend(qctx.response)


def main() -> None:
    server = AsyncDnsServer(default_aa=True, default_rcode=dns.rcode.NOERROR)
    server.install_response_handler(AttackerAuthority())
    server.run()


if __name__ == "__main__":
    main()