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https://github.com/isc-projects/bind9.git
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8cb51d4c2b
Add a main() function to all custom servers based on isctest.asyncserver and move server startup code there. This prevents redefining variables from outer scope in custom server code as it evolves.
115 lines
3.1 KiB
Python
115 lines
3.1 KiB
Python
"""
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Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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SPDX-License-Identifier: MPL-2.0
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This Source Code Form is subject to the terms of the Mozilla Public
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License, v. 2.0. If a copy of the MPL was not distributed with this
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file, you can obtain one at https://mozilla.org/MPL/2.0/.
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See the COPYRIGHT file distributed with this work for additional
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information regarding copyright ownership.
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"""
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from typing import AsyncGenerator
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import dns.message
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import dns.name
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import dns.rcode
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import dns.rdataclass
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import dns.rdatatype
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from isctest.asyncserver import (
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AsyncDnsServer,
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DnsResponseSend,
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DomainHandler,
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QueryContext,
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ResponseAction,
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)
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from qmin_ans import (
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DelayedResponseHandler,
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EntRcodeChanger,
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QueryLogHandler,
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log_query,
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)
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class QueryLogger(QueryLogHandler):
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domains = ["1.0.0.2.ip6.arpa.", "fwd.", "good."]
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class BadHandler(EntRcodeChanger):
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domains = ["bad."]
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rcode = dns.rcode.NXDOMAIN
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class UglyHandler(EntRcodeChanger):
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domains = ["ugly."]
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rcode = dns.rcode.FORMERR
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class SlowHandler(DelayedResponseHandler):
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domains = ["slow."]
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delay = 0.2
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def send_delegation(
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qctx: QueryContext, zone_cut: dns.name.Name, target_addr: str
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) -> ResponseAction:
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"""
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Delegate `zone_cut` to a single in-bailiwick name server, `ns.<zone_cut>`,
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with a single IPv4 glue record (provided in `target_addr`) included in the
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ADDITIONAL section.
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"""
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ns_name = "ns." + zone_cut.to_text()
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ns_rrset = dns.rrset.from_text(
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zone_cut, 2, dns.rdataclass.IN, dns.rdatatype.NS, ns_name
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)
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a_rrset = dns.rrset.from_text(
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ns_name, 2, dns.rdataclass.IN, dns.rdatatype.A, target_addr
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)
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response = dns.message.make_response(qctx.query)
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response.set_rcode(dns.rcode.NOERROR)
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response.authority.append(ns_rrset)
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response.additional.append(a_rrset)
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return DnsResponseSend(response, authoritative=False)
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class StaleHandler(DomainHandler):
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"""
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`a.b.stale` is a subdomain of `b.stale` and these two subdomains need to be
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delegated to different name servers. Therefore, their delegations cannot
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be placed in the zone file because the zone cut at `b.stale` would occlude
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the one at `a.b.stale`. Generate these delegations dynamically depending
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on the QNAME.
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"""
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domains = ["stale."]
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async def get_responses(
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self, qctx: QueryContext
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) -> AsyncGenerator[ResponseAction, None]:
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log_query(qctx)
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a_b_stale = dns.name.from_text("a.b.stale.")
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b_stale = dns.name.from_text("b.stale.")
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if qctx.qname.is_subdomain(a_b_stale):
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yield send_delegation(qctx, a_b_stale, "10.53.0.3")
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elif qctx.qname.is_subdomain(b_stale):
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yield send_delegation(qctx, b_stale, "10.53.0.4")
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def main() -> None:
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server = AsyncDnsServer()
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server.install_response_handler(QueryLogger())
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server.install_response_handler(BadHandler())
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server.install_response_handler(UglyHandler())
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server.install_response_handler(SlowHandler())
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server.install_response_handler(StaleHandler())
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server.run()
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if __name__ == "__main__":
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main()
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