andreasandClaude Sonnet 5.5
885d5dc937
hbc, hbc_mini.py and hbc_mini.c resolved the server once at startup, so an address change needed a client restart. They now re-resolve every TTL seconds (smallest A/AAAA TTL, floor 30s, 300s when unknown) and re-point, add or drop connections to follow the new addresses; a failed lookup keeps the current ones. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
73 lines
2.6 KiB
Python
73 lines
2.6 KiB
Python
"""TTL-driven re-resolution in the standalone scripts/hbc_mini.py."""
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import asyncio
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import importlib.util
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import pathlib
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import socket
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import struct
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import sys
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_PATH = pathlib.Path(__file__).resolve().parents[1] / "scripts" / "hbc_mini.py"
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_SPEC = importlib.util.spec_from_file_location("hbc_mini", _PATH)
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mini = importlib.util.module_from_spec(_SPEC)
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sys.modules["hbc_mini"] = mini
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_SPEC.loader.exec_module(mini)
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V4, V6 = socket.AF_INET, socket.AF_INET6
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def _rr(rtype, ttl, rdata):
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return b"\xc0\x0c" + struct.pack("!HHIH", rtype, 1, ttl, len(rdata)) + rdata
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def _response(qid, qtype, answers, rcode=0):
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q = mini._dns_build_query("hbd.example.com", qtype, qid)[12:]
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return struct.pack("!HHHHHH", qid, 0x8180 | rcode, 1, len(answers), 0, 0) + q + b"".join(answers)
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def test_min_ttl_covers_cname_and_address():
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resp = _response(7, 1, [_rr(5, 60, b"\x01x\x00"), _rr(1, 300, b"\x01\x02\x03\x04")])
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assert mini._dns_min_answer_ttl(resp, 7, 1) == 60
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def test_unknown_ttl_cases():
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assert mini._dns_min_answer_ttl(_response(7, 28, []), 7, 28) is None
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assert mini._dns_min_answer_ttl(_response(7, 1, [_rr(1, 9, b"1234")], rcode=3), 7, 1) is None
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assert mini._dns_min_answer_ttl(b"\x00\x07\x81", 7, 1) is None
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assert mini._dns_lookup_ttl("192.0.2.1") is None
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def test_refresh_delay():
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assert mini._dns_refresh_delay([300, 120, None]) == 120
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assert mini._dns_refresh_delay([0]) == mini._DNS_MIN_TTL
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assert mini._dns_refresh_delay([None]) == mini._DNS_DEFAULT_TTL
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def test_refresher_follows_a_change_and_adds_a_family(monkeypatch):
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answers = [[(V4, "9.9.9.9"), (V6, "2001:db8::9")], None, [(V4, "9.9.9.9")]]
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monkeypatch.setattr(mini, "_dns_resolve", lambda *a: answers.pop(0) if len(answers) > 1 else answers[0])
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monkeypatch.setattr(mini, "_dns_lookup_ttl", lambda *a: None)
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monkeypatch.setattr(mini, "_DNS_DEFAULT_TTL", 0.01)
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monkeypatch.setattr(mini, "_DNS_FAILED_RETRY", 0.01)
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async def idle(*a):
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await asyncio.sleep(10)
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monkeypatch.setattr(mini, "_heartbeat_sender", idle)
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async def go():
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mini._running = True
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mini._shutdown_event = asyncio.Event()
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mini._active_tasks = []
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conns = [mini.AsyncConnection(1, "1.1.1.1", 5, V4, "me")]
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task = asyncio.create_task(mini._dns_refresher(conns, ["h"], 5, 0, "me", 10, None, 2))
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await asyncio.sleep(0.2)
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mini._running = False
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mini._shutdown_event.set()
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await task
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for t in mini._active_tasks:
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t.cancel()
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return conns
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conns = asyncio.run(go())
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assert [(c.conn_id, c.addr) for c in conns] == [(1, "9.9.9.9")]
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assert conns[0].af == V4
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