-
-
Notifications
You must be signed in to change notification settings - Fork 2k
/
resolver.py
189 lines (158 loc) · 6.27 KB
/
resolver.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
import asyncio
import socket
import sys
from typing import Any, Dict, List, Optional, Tuple, Type, Union
from .abc import AbstractResolver, ResolveResult
from .helpers import get_running_loop
__all__ = ("ThreadedResolver", "AsyncResolver", "DefaultResolver")
try:
import aiodns
# aiodns_default = hasattr(aiodns.DNSResolver, 'getaddrinfo')
except ImportError: # pragma: no cover
aiodns = None # type: ignore[assignment]
aiodns_default = False
_NUMERIC_SOCKET_FLAGS = socket.AI_NUMERICHOST | socket.AI_NUMERICSERV
_SUPPORTS_SCOPE_ID = sys.version_info >= (3, 9, 0)
class ThreadedResolver(AbstractResolver):
"""Threaded resolver.
Uses an Executor for synchronous getaddrinfo() calls.
concurrent.futures.ThreadPoolExecutor is used by default.
"""
def __init__(self, loop: Optional[asyncio.AbstractEventLoop] = None) -> None:
self._loop = get_running_loop(loop)
async def resolve(
self, host: str, port: int = 0, family: socket.AddressFamily = socket.AF_INET
) -> List[ResolveResult]:
infos = await self._loop.getaddrinfo(
host,
port,
type=socket.SOCK_STREAM,
family=family,
flags=socket.AI_ADDRCONFIG,
)
hosts: List[ResolveResult] = []
for family, _, proto, _, address in infos:
if family == socket.AF_INET6:
if len(address) < 3:
# IPv6 is not supported by Python build,
# or IPv6 is not enabled in the host
continue
if address[3] and _SUPPORTS_SCOPE_ID:
# This is essential for link-local IPv6 addresses.
# LL IPv6 is a VERY rare case. Strictly speaking, we should use
# getnameinfo() unconditionally, but performance makes sense.
resolved_host, _port = await self._loop.getnameinfo(
address, _NUMERIC_SOCKET_FLAGS
)
port = int(_port)
else:
resolved_host, port = address[:2]
else: # IPv4
assert family == socket.AF_INET
resolved_host, port = address # type: ignore[misc]
hosts.append(
ResolveResult(
hostname=host,
host=resolved_host,
port=port,
family=family,
proto=proto,
flags=_NUMERIC_SOCKET_FLAGS,
)
)
return hosts
async def close(self) -> None:
pass
class AsyncResolver(AbstractResolver):
"""Use the `aiodns` package to make asynchronous DNS lookups"""
def __init__(
self,
loop: Optional[asyncio.AbstractEventLoop] = None,
*args: Any,
**kwargs: Any
) -> None:
if aiodns is None:
raise RuntimeError("Resolver requires aiodns library")
self._resolver = aiodns.DNSResolver(*args, **kwargs)
if not hasattr(self._resolver, "gethostbyname"):
# aiodns 1.1 is not available, fallback to DNSResolver.query
self.resolve = self._resolve_with_query # type: ignore
async def resolve(
self, host: str, port: int = 0, family: socket.AddressFamily = socket.AF_INET
) -> List[ResolveResult]:
try:
resp = await self._resolver.getaddrinfo(
host,
port=port,
type=socket.SOCK_STREAM,
family=family,
flags=socket.AI_ADDRCONFIG,
)
except aiodns.error.DNSError as exc:
msg = exc.args[1] if len(exc.args) >= 1 else "DNS lookup failed"
raise OSError(msg) from exc
hosts: List[ResolveResult] = []
for node in resp.nodes:
address: Union[Tuple[bytes, int], Tuple[bytes, int, int, int]] = node.addr
family = node.family
if family == socket.AF_INET6:
if len(address) > 3 and address[3] and _SUPPORTS_SCOPE_ID:
# This is essential for link-local IPv6 addresses.
# LL IPv6 is a VERY rare case. Strictly speaking, we should use
# getnameinfo() unconditionally, but performance makes sense.
result = await self._resolver.getnameinfo(
(address[0].decode("ascii"), *address[1:]),
_NUMERIC_SOCKET_FLAGS,
)
resolved_host = result.node
else:
resolved_host = address[0].decode("ascii")
port = address[1]
else: # IPv4
assert family == socket.AF_INET
resolved_host = address[0].decode("ascii")
port = address[1]
hosts.append(
ResolveResult(
hostname=host,
host=resolved_host,
port=port,
family=family,
proto=0,
flags=_NUMERIC_SOCKET_FLAGS,
)
)
if not hosts:
raise OSError("DNS lookup failed")
return hosts
async def _resolve_with_query(
self, host: str, port: int = 0, family: int = socket.AF_INET
) -> List[Dict[str, Any]]:
if family == socket.AF_INET6:
qtype = "AAAA"
else:
qtype = "A"
try:
resp = await self._resolver.query(host, qtype)
except aiodns.error.DNSError as exc:
msg = exc.args[1] if len(exc.args) >= 1 else "DNS lookup failed"
raise OSError(msg) from exc
hosts = []
for rr in resp:
hosts.append(
{
"hostname": host,
"host": rr.host,
"port": port,
"family": family,
"proto": 0,
"flags": socket.AI_NUMERICHOST,
}
)
if not hosts:
raise OSError("DNS lookup failed")
return hosts
async def close(self) -> None:
self._resolver.cancel()
_DefaultType = Type[Union[AsyncResolver, ThreadedResolver]]
DefaultResolver: _DefaultType = AsyncResolver if aiodns_default else ThreadedResolver