summaryrefslogtreecommitdiffhomepage
path: root/libs/dns/_trio_backend.py
blob: 398e3276923bb6ae91d14a12de5d089cd134d7bb (plain)
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
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license

"""trio async I/O library query support"""

import socket

import trio
import trio.socket  # type: ignore

import dns._asyncbackend
import dns._features
import dns.exception
import dns.inet

if not dns._features.have("trio"):
    raise ImportError("trio not found or too old")


def _maybe_timeout(timeout):
    if timeout is not None:
        return trio.move_on_after(timeout)
    else:
        return dns._asyncbackend.NullContext()


# for brevity
_lltuple = dns.inet.low_level_address_tuple

# pylint: disable=redefined-outer-name


class DatagramSocket(dns._asyncbackend.DatagramSocket):
    def __init__(self, socket):
        super().__init__(socket.family)
        self.socket = socket

    async def sendto(self, what, destination, timeout):
        with _maybe_timeout(timeout):
            return await self.socket.sendto(what, destination)
        raise dns.exception.Timeout(
            timeout=timeout
        )  # pragma: no cover  lgtm[py/unreachable-statement]

    async def recvfrom(self, size, timeout):
        with _maybe_timeout(timeout):
            return await self.socket.recvfrom(size)
        raise dns.exception.Timeout(timeout=timeout)  # lgtm[py/unreachable-statement]

    async def close(self):
        self.socket.close()

    async def getpeername(self):
        return self.socket.getpeername()

    async def getsockname(self):
        return self.socket.getsockname()

    async def getpeercert(self, timeout):
        raise NotImplementedError


class StreamSocket(dns._asyncbackend.StreamSocket):
    def __init__(self, family, stream, tls=False):
        self.family = family
        self.stream = stream
        self.tls = tls

    async def sendall(self, what, timeout):
        with _maybe_timeout(timeout):
            return await self.stream.send_all(what)
        raise dns.exception.Timeout(timeout=timeout)  # lgtm[py/unreachable-statement]

    async def recv(self, size, timeout):
        with _maybe_timeout(timeout):
            return await self.stream.receive_some(size)
        raise dns.exception.Timeout(timeout=timeout)  # lgtm[py/unreachable-statement]

    async def close(self):
        await self.stream.aclose()

    async def getpeername(self):
        if self.tls:
            return self.stream.transport_stream.socket.getpeername()
        else:
            return self.stream.socket.getpeername()

    async def getsockname(self):
        if self.tls:
            return self.stream.transport_stream.socket.getsockname()
        else:
            return self.stream.socket.getsockname()

    async def getpeercert(self, timeout):
        if self.tls:
            with _maybe_timeout(timeout):
                await self.stream.do_handshake()
            return self.stream.getpeercert()
        else:
            raise NotImplementedError


if dns._features.have("doh"):
    import httpcore
    import httpcore._backends.trio
    import httpx

    _CoreAsyncNetworkBackend = httpcore.AsyncNetworkBackend
    _CoreTrioStream = httpcore._backends.trio.TrioStream

    from dns.query import _compute_times, _expiration_for_this_attempt, _remaining

    class _NetworkBackend(_CoreAsyncNetworkBackend):
        def __init__(self, resolver, local_port, bootstrap_address, family):
            super().__init__()
            self._local_port = local_port
            self._resolver = resolver
            self._bootstrap_address = bootstrap_address
            self._family = family

        async def connect_tcp(
            self, host, port, timeout, local_address, socket_options=None
        ):  # pylint: disable=signature-differs
            addresses = []
            _, expiration = _compute_times(timeout)
            if dns.inet.is_address(host):
                addresses.append(host)
            elif self._bootstrap_address is not None:
                addresses.append(self._bootstrap_address)
            else:
                timeout = _remaining(expiration)
                family = self._family
                if local_address:
                    family = dns.inet.af_for_address(local_address)
                answers = await self._resolver.resolve_name(
                    host, family=family, lifetime=timeout
                )
                addresses = answers.addresses()
            for address in addresses:
                try:
                    af = dns.inet.af_for_address(address)
                    if local_address is not None or self._local_port != 0:
                        source = (local_address, self._local_port)
                    else:
                        source = None
                    destination = (address, port)
                    attempt_expiration = _expiration_for_this_attempt(2.0, expiration)
                    timeout = _remaining(attempt_expiration)
                    sock = await Backend().make_socket(
                        af, socket.SOCK_STREAM, 0, source, destination, timeout
                    )
                    return _CoreTrioStream(sock.stream)
                except Exception:
                    continue
            raise httpcore.ConnectError

        async def connect_unix_socket(
            self, path, timeout, socket_options=None
        ):  # pylint: disable=signature-differs
            raise NotImplementedError

        async def sleep(self, seconds):  # pylint: disable=signature-differs
            await trio.sleep(seconds)

    class _HTTPTransport(httpx.AsyncHTTPTransport):
        def __init__(
            self,
            *args,
            local_port=0,
            bootstrap_address=None,
            resolver=None,
            family=socket.AF_UNSPEC,
            **kwargs,
        ):
            if resolver is None:
                # pylint: disable=import-outside-toplevel,redefined-outer-name
                import dns.asyncresolver

                resolver = dns.asyncresolver.Resolver()
            super().__init__(*args, **kwargs)
            self._pool._network_backend = _NetworkBackend(
                resolver, local_port, bootstrap_address, family
            )

else:
    _HTTPTransport = dns._asyncbackend.NullTransport  # type: ignore


class Backend(dns._asyncbackend.Backend):
    def name(self):
        return "trio"

    async def make_socket(
        self,
        af,
        socktype,
        proto=0,
        source=None,
        destination=None,
        timeout=None,
        ssl_context=None,
        server_hostname=None,
    ):
        s = trio.socket.socket(af, socktype, proto)
        stream = None
        try:
            if source:
                await s.bind(_lltuple(source, af))
            if socktype == socket.SOCK_STREAM:
                connected = False
                with _maybe_timeout(timeout):
                    await s.connect(_lltuple(destination, af))
                    connected = True
                if not connected:
                    raise dns.exception.Timeout(
                        timeout=timeout
                    )  # lgtm[py/unreachable-statement]
        except Exception:  # pragma: no cover
            s.close()
            raise
        if socktype == socket.SOCK_DGRAM:
            return DatagramSocket(s)
        elif socktype == socket.SOCK_STREAM:
            stream = trio.SocketStream(s)
            tls = False
            if ssl_context:
                tls = True
                try:
                    stream = trio.SSLStream(
                        stream, ssl_context, server_hostname=server_hostname
                    )
                except Exception:  # pragma: no cover
                    await stream.aclose()
                    raise
            return StreamSocket(af, stream, tls)
        raise NotImplementedError(
            "unsupported socket " + f"type {socktype}"
        )  # pragma: no cover

    async def sleep(self, interval):
        await trio.sleep(interval)

    def get_transport_class(self):
        return _HTTPTransport

    async def wait_for(self, awaitable, timeout):
        with _maybe_timeout(timeout):
            return await awaitable
        raise dns.exception.Timeout(
            timeout=timeout
        )  # pragma: no cover  lgtm[py/unreachable-statement]