Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/tornado/netutil.py: 26%

1# 

2# Copyright 2011 Facebook 

3# 

4# Licensed under the Apache License, Version 2.0 (the "License"); you may 

5# not use this file except in compliance with the License. You may obtain 

6# a copy of the License at 

7# 

8# http://www.apache.org/licenses/LICENSE-2.0 

9# 

10# Unless required by applicable law or agreed to in writing, software 

11# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 

12# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 

13# License for the specific language governing permissions and limitations 

14# under the License. 

15 

16"""Miscellaneous network utility code.""" 

17 

18import asyncio 

19import concurrent.futures 

20import errno 

21import os 

22import sys 

23import socket 

24import ssl 

25import stat 

26 

27from tornado.concurrent import dummy_executor, run_on_executor 

28from tornado.ioloop import IOLoop 

29from tornado.util import Configurable, errno_from_exception 

30 

31from typing import List, Callable, Any, Type, Dict, Union, Tuple, Awaitable, Optional 

32 

33# Note that the naming of ssl.Purpose is confusing; the purpose 

34# of a context is to authenticate the opposite side of the connection. 

35_client_ssl_defaults = ssl.create_default_context(ssl.Purpose.SERVER_AUTH) 

36_server_ssl_defaults = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH) 

37if hasattr(ssl, "OP_NO_COMPRESSION"): 

38 # See netutil.ssl_options_to_context 

39 _client_ssl_defaults.options |= ssl.OP_NO_COMPRESSION 

40 _server_ssl_defaults.options |= ssl.OP_NO_COMPRESSION 

41 

42# ThreadedResolver runs getaddrinfo on a thread. If the hostname is unicode, 

43# getaddrinfo attempts to import encodings.idna. If this is done at 

44# module-import time, the import lock is already held by the main thread, 

45# leading to deadlock. Avoid it by caching the idna encoder on the main 

46# thread now. 

47"foo".encode("idna") 

48 

49# For undiagnosed reasons, 'latin1' codec may also need to be preloaded. 

50"foo".encode("latin1") 

51 

52# Default backlog used when calling sock.listen() 

53_DEFAULT_BACKLOG = 128 

54 

55 

56def bind_sockets( 

57 port: int, 

58 address: Optional[str] = None, 

59 family: socket.AddressFamily = socket.AF_UNSPEC, 

60 backlog: int = _DEFAULT_BACKLOG, 

61 flags: Optional[int] = None, 

62 reuse_port: bool = False, 

63) -> List[socket.socket]: 

64 """Creates listening sockets bound to the given port and address. 

65 

66 Returns a list of socket objects (multiple sockets are returned if 

67 the given address maps to multiple IP addresses, which is most common 

68 for mixed IPv4 and IPv6 use). 

69 

70 Address may be either an IP address or hostname. If it's a hostname, 

71 the server will listen on all IP addresses associated with the 

72 name. Address may be an empty string or None to listen on all 

73 available interfaces. Family may be set to either `socket.AF_INET` 

74 or `socket.AF_INET6` to restrict to IPv4 or IPv6 addresses, otherwise 

75 both will be used if available. 

76 

77 The ``backlog`` argument has the same meaning as for 

78 `socket.listen() <socket.socket.listen>`. 

79 

80 ``flags`` is a bitmask of AI_* flags to `~socket.getaddrinfo`, like 

81 ``socket.AI_PASSIVE | socket.AI_NUMERICHOST``. 

82 

83 ``reuse_port`` option sets ``SO_REUSEPORT`` option for every socket 

84 in the list. If your platform doesn't support this option ValueError will 

85 be raised. 

86 """ 

87 if reuse_port and not hasattr(socket, "SO_REUSEPORT"): 

88 raise ValueError("the platform doesn't support SO_REUSEPORT") 

89 

90 sockets = [] 

91 if address == "": 

92 address = None 

93 if not socket.has_ipv6 and family == socket.AF_UNSPEC: 

94 # Python can be compiled with --disable-ipv6, which causes 

95 # operations on AF_INET6 sockets to fail, but does not 

96 # automatically exclude those results from getaddrinfo 

97 # results. 

98 # http://bugs.python.org/issue16208 

99 family = socket.AF_INET 

100 if flags is None: 

101 flags = socket.AI_PASSIVE 

102 bound_port = None 

103 unique_addresses = set() # type: set 

104 for res in sorted( 

105 socket.getaddrinfo(address, port, family, socket.SOCK_STREAM, 0, flags), 

106 key=lambda x: x[0], 

107 ): 

108 if res in unique_addresses: 

109 continue 

110 

111 unique_addresses.add(res) 

112 

113 af, socktype, proto, canonname, sockaddr = res 

114 if ( 

115 sys.platform == "darwin" 

116 and address == "localhost" 

117 and af == socket.AF_INET6 

118 and sockaddr[3] != 0 # type: ignore 

119 ): 

120 # Mac OS X includes a link-local address fe80::1%lo0 in the 

121 # getaddrinfo results for 'localhost'. However, the firewall 

122 # doesn't understand that this is a local address and will 

123 # prompt for access (often repeatedly, due to an apparent 

124 # bug in its ability to remember granting access to an 

125 # application). Skip these addresses. 

126 continue 

127 try: 

128 sock = socket.socket(af, socktype, proto) 

129 except OSError as e: 

130 if errno_from_exception(e) == errno.EAFNOSUPPORT: 

131 continue 

132 raise 

133 if os.name != "nt": 

134 try: 

135 sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) 

136 except OSError as e: 

137 if errno_from_exception(e) != errno.ENOPROTOOPT: 

138 # Hurd doesn't support SO_REUSEADDR. 

139 raise 

140 if reuse_port: 

141 sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1) 

142 if af == socket.AF_INET6: 

143 # On linux, ipv6 sockets accept ipv4 too by default, 

144 # but this makes it impossible to bind to both 

145 # 0.0.0.0 in ipv4 and :: in ipv6. On other systems, 

146 # separate sockets *must* be used to listen for both ipv4 

147 # and ipv6. For consistency, always disable ipv4 on our 

148 # ipv6 sockets and use a separate ipv4 socket when needed. 

149 # 

150 # Python 2.x on windows doesn't have IPPROTO_IPV6. 

151 if hasattr(socket, "IPPROTO_IPV6"): 

152 sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 1) 

153 

154 # automatic port allocation with port=None 

155 # should bind on the same port on IPv4 and IPv6 

156 host, requested_port = sockaddr[:2] 

157 if requested_port == 0 and bound_port is not None: 

158 sockaddr = tuple([host, bound_port] + list(sockaddr[2:])) 

159 

160 sock.setblocking(False) 

161 try: 

162 sock.bind(sockaddr) 

163 except OSError as e: 

164 if ( 

165 errno_from_exception(e) == errno.EADDRNOTAVAIL 

166 and address == "localhost" 

167 and sockaddr[0] == "::1" 

168 ): 

169 # On some systems (most notably docker with default 

170 # configurations), ipv6 is partially disabled: 

171 # socket.has_ipv6 is true, we can create AF_INET6 

172 # sockets, and getaddrinfo("localhost", ..., 

173 # AF_PASSIVE) resolves to ::1, but we get an error 

174 # when binding. 

175 # 

176 # Swallow the error, but only for this specific case. 

177 # If EADDRNOTAVAIL occurs in other situations, it 

178 # might be a real problem like a typo in a 

179 # configuration. 

180 sock.close() 

181 continue 

182 else: 

183 raise 

184 bound_port = sock.getsockname()[1] 

185 sock.listen(backlog) 

186 sockets.append(sock) 

187 return sockets 

188 

189 

190if hasattr(socket, "AF_UNIX"): 

191 

192 def bind_unix_socket( 

193 file: str, mode: int = 0o600, backlog: int = _DEFAULT_BACKLOG 

194 ) -> socket.socket: 

195 """Creates a listening unix socket. 

196 

197 If a socket with the given name already exists, it will be deleted. 

198 If any other file with that name exists, an exception will be 

199 raised. 

200 

201 Returns a socket object (not a list of socket objects like 

202 `bind_sockets`) 

203 """ 

204 sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) 

205 try: 

206 sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) 

207 except OSError as e: 

208 if errno_from_exception(e) != errno.ENOPROTOOPT: 

209 # Hurd doesn't support SO_REUSEADDR 

210 raise 

211 sock.setblocking(False) 

212 # File names comprising of an initial null-byte denote an abstract 

213 # namespace, on Linux, and therefore are not subject to file system 

214 # orientated processing. 

215 if not file.startswith("\0"): 

216 try: 

217 st = os.stat(file) 

218 except FileNotFoundError: 

219 pass 

220 else: 

221 if stat.S_ISSOCK(st.st_mode): 

222 os.remove(file) 

223 else: 

224 raise ValueError("File %s exists and is not a socket", file) 

225 sock.bind(file) 

226 os.chmod(file, mode) 

227 else: 

228 sock.bind(file) 

229 sock.listen(backlog) 

230 return sock 

231 

232 

233def add_accept_handler( 

234 sock: socket.socket, callback: Callable[[socket.socket, Any], None] 

235) -> Callable[[], None]: 

236 """Adds an `.IOLoop` event handler to accept new connections on ``sock``. 

237 

238 When a connection is accepted, ``callback(connection, address)`` will 

239 be run (``connection`` is a socket object, and ``address`` is the 

240 address of the other end of the connection). Note that this signature 

241 is different from the ``callback(fd, events)`` signature used for 

242 `.IOLoop` handlers. 

243 

244 A callable is returned which, when called, will remove the `.IOLoop` 

245 event handler and stop processing further incoming connections. 

246 

247 .. versionchanged:: 5.0 

248 The ``io_loop`` argument (deprecated since version 4.1) has been removed. 

249 

250 .. versionchanged:: 5.0 

251 A callable is returned (``None`` was returned before). 

252 """ 

253 io_loop = IOLoop.current() 

254 removed = [False] 

255 

256 def accept_handler(fd: socket.socket, events: int) -> None: 

257 # More connections may come in while we're handling callbacks; 

258 # to prevent starvation of other tasks we must limit the number 

259 # of connections we accept at a time. Ideally we would accept 

260 # up to the number of connections that were waiting when we 

261 # entered this method, but this information is not available 

262 # (and rearranging this method to call accept() as many times 

263 # as possible before running any callbacks would have adverse 

264 # effects on load balancing in multiprocess configurations). 

265 # Instead, we use the (default) listen backlog as a rough 

266 # heuristic for the number of connections we can reasonably 

267 # accept at once. 

268 for i in range(_DEFAULT_BACKLOG): 

269 if removed[0]: 

270 # The socket was probably closed 

271 return 

272 try: 

273 connection, address = sock.accept() 

274 except BlockingIOError: 

275 # EWOULDBLOCK indicates we have accepted every 

276 # connection that is available. 

277 return 

278 except ConnectionAbortedError: 

279 # ECONNABORTED indicates that there was a connection 

280 # but it was closed while still in the accept queue. 

281 # (observed on FreeBSD). 

282 continue 

283 callback(connection, address) 

284 

285 def remove_handler() -> None: 

286 io_loop.remove_handler(sock) 

287 removed[0] = True 

288 

289 io_loop.add_handler(sock, accept_handler, IOLoop.READ) 

290 return remove_handler 

291 

292 

293def is_valid_ip(ip: str) -> bool: 

294 """Returns ``True`` if the given string is a well-formed IP address. 

295 

296 Supports IPv4 and IPv6. 

297 """ 

298 if not ip or "\x00" in ip: 

299 # getaddrinfo resolves empty strings to localhost, and truncates 

300 # on zero bytes. 

301 return False 

302 try: 

303 res = socket.getaddrinfo( 

304 ip, 0, socket.AF_UNSPEC, socket.SOCK_STREAM, 0, socket.AI_NUMERICHOST 

305 ) 

306 return bool(res) 

307 except socket.gaierror as e: 

308 if e.args[0] == socket.EAI_NONAME: 

309 return False 

310 raise 

311 except UnicodeError: 

312 # `socket.getaddrinfo` will raise a UnicodeError from the 

313 # `idna` decoder if the input is longer than 63 characters, 

314 # even for socket.AI_NUMERICHOST. See 

315 # https://bugs.python.org/issue32958 for discussion 

316 return False 

317 return True 

318 

319 

320class Resolver(Configurable): 

321 """Configurable asynchronous DNS resolver interface. 

322 

323 By default, a blocking implementation is used (which simply calls 

324 `socket.getaddrinfo`). An alternative implementation can be 

325 chosen with the `Resolver.configure <.Configurable.configure>` 

326 class method:: 

327 

328 Resolver.configure('tornado.netutil.ThreadedResolver') 

329 

330 The implementations of this interface included with Tornado are 

331 

332 * `tornado.netutil.DefaultLoopResolver` 

333 * `tornado.netutil.DefaultExecutorResolver` (deprecated) 

334 * `tornado.netutil.BlockingResolver` (deprecated) 

335 * `tornado.netutil.ThreadedResolver` (deprecated) 

336 * `tornado.netutil.OverrideResolver` 

337 * `tornado.platform.caresresolver.CaresResolver` (deprecated) 

338 

339 .. versionchanged:: 5.0 

340 The default implementation has changed from `BlockingResolver` to 

341 `DefaultExecutorResolver`. 

342 

343 .. versionchanged:: 6.2 

344 The default implementation has changed from `DefaultExecutorResolver` to 

345 `DefaultLoopResolver`. 

346 """ 

347 

348 @classmethod 

349 def configurable_base(cls) -> Type["Resolver"]: 

350 return Resolver 

351 

352 @classmethod 

353 def configurable_default(cls) -> Type["Resolver"]: 

354 return DefaultLoopResolver 

355 

356 def resolve( 

357 self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC 

358 ) -> Awaitable[List[Tuple[int, Any]]]: 

359 """Resolves an address. 

360 

361 The ``host`` argument is a string which may be a hostname or a 

362 literal IP address. 

363 

364 Returns a `.Future` whose result is a list of (family, 

365 address) pairs, where address is a tuple suitable to pass to 

366 `socket.connect <socket.socket.connect>` (i.e. a ``(host, 

367 port)`` pair for IPv4; additional fields may be present for 

368 IPv6). If a ``callback`` is passed, it will be run with the 

369 result as an argument when it is complete. 

370 

371 :raises IOError: if the address cannot be resolved. 

372 

373 .. versionchanged:: 4.4 

374 Standardized all implementations to raise `IOError`. 

375 

376 .. versionchanged:: 6.0 The ``callback`` argument was removed. 

377 Use the returned awaitable object instead. 

378 

379 """ 

380 raise NotImplementedError() 

381 

382 def close(self) -> None: 

383 """Closes the `Resolver`, freeing any resources used. 

384 

385 .. versionadded:: 3.1 

386 

387 """ 

388 pass 

389 

390 

391def _resolve_addr( 

392 host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC 

393) -> List[Tuple[int, Any]]: 

394 # On Solaris, getaddrinfo fails if the given port is not found 

395 # in /etc/services and no socket type is given, so we must pass 

396 # one here. The socket type used here doesn't seem to actually 

397 # matter (we discard the one we get back in the results), 

398 # so the addresses we return should still be usable with SOCK_DGRAM. 

399 addrinfo = socket.getaddrinfo(host, port, family, socket.SOCK_STREAM) 

400 results = [] 

401 for fam, socktype, proto, canonname, address in addrinfo: 

402 results.append((fam, address)) 

403 return results # type: ignore 

404 

405 

406class DefaultExecutorResolver(Resolver): 

407 """Resolver implementation using `.IOLoop.run_in_executor`. 

408 

409 .. versionadded:: 5.0 

410 

411 .. deprecated:: 6.2 

412 

413 Use `DefaultLoopResolver` instead. 

414 """ 

415 

416 async def resolve( 

417 self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC 

418 ) -> List[Tuple[int, Any]]: 

419 result = await IOLoop.current().run_in_executor( 

420 None, _resolve_addr, host, port, family 

421 ) 

422 return result 

423 

424 

425class DefaultLoopResolver(Resolver): 

426 """Resolver implementation using `asyncio.loop.getaddrinfo`.""" 

427 

428 async def resolve( 

429 self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC 

430 ) -> List[Tuple[int, Any]]: 

431 # On Solaris, getaddrinfo fails if the given port is not found 

432 # in /etc/services and no socket type is given, so we must pass 

433 # one here. The socket type used here doesn't seem to actually 

434 # matter (we discard the one we get back in the results), 

435 # so the addresses we return should still be usable with SOCK_DGRAM. 

436 return [ 

437 (fam, address) 

438 for fam, _, _, _, address in await asyncio.get_running_loop().getaddrinfo( 

439 host, port, family=family, type=socket.SOCK_STREAM 

440 ) 

441 ] 

442 

443 

444class ExecutorResolver(Resolver): 

445 """Resolver implementation using a `concurrent.futures.Executor`. 

446 

447 Use this instead of `ThreadedResolver` when you require additional 

448 control over the executor being used. 

449 

450 The executor will be shut down when the resolver is closed unless 

451 ``close_resolver=False``; use this if you want to reuse the same 

452 executor elsewhere. 

453 

454 .. versionchanged:: 5.0 

455 The ``io_loop`` argument (deprecated since version 4.1) has been removed. 

456 

457 .. deprecated:: 5.0 

458 The default `Resolver` now uses `asyncio.loop.getaddrinfo`; 

459 use that instead of this class. 

460 """ 

461 

462 def initialize( 

463 self, 

464 executor: Optional[concurrent.futures.Executor] = None, 

465 close_executor: bool = True, 

466 ) -> None: 

467 if executor is not None: 

468 self.executor = executor 

469 self.close_executor = close_executor 

470 else: 

471 self.executor = dummy_executor 

472 self.close_executor = False 

473 

474 def close(self) -> None: 

475 if self.close_executor: 

476 self.executor.shutdown() 

477 self.executor = None # type: ignore 

478 

479 @run_on_executor 

480 def resolve( 

481 self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC 

482 ) -> List[Tuple[int, Any]]: 

483 return _resolve_addr(host, port, family) 

484 

485 

486class BlockingResolver(ExecutorResolver): 

487 """Default `Resolver` implementation, using `socket.getaddrinfo`. 

488 

489 The `.IOLoop` will be blocked during the resolution, although the 

490 callback will not be run until the next `.IOLoop` iteration. 

491 

492 .. deprecated:: 5.0 

493 The default `Resolver` now uses `.IOLoop.run_in_executor`; use that instead 

494 of this class. 

495 """ 

496 

497 def initialize(self) -> None: # type: ignore 

498 super().initialize() 

499 

500 

501class ThreadedResolver(ExecutorResolver): 

502 """Multithreaded non-blocking `Resolver` implementation. 

503 

504 The thread pool size can be configured with:: 

505 

506 Resolver.configure('tornado.netutil.ThreadedResolver', 

507 num_threads=10) 

508 

509 .. versionchanged:: 3.1 

510 All ``ThreadedResolvers`` share a single thread pool, whose 

511 size is set by the first one to be created. 

512 

513 .. deprecated:: 5.0 

514 The default `Resolver` now uses `.IOLoop.run_in_executor`; use that instead 

515 of this class. 

516 """ 

517 

518 _threadpool = None # type: ignore 

519 _threadpool_pid = None # type: int 

520 

521 def initialize(self, num_threads: int = 10) -> None: # type: ignore 

522 threadpool = ThreadedResolver._create_threadpool(num_threads) 

523 super().initialize(executor=threadpool, close_executor=False) 

524 

525 @classmethod 

526 def _create_threadpool( 

527 cls, num_threads: int 

528 ) -> concurrent.futures.ThreadPoolExecutor: 

529 pid = os.getpid() 

530 if cls._threadpool_pid != pid: 

531 # Threads cannot survive after a fork, so if our pid isn't what it 

532 # was when we created the pool then delete it. 

533 cls._threadpool = None 

534 if cls._threadpool is None: 

535 cls._threadpool = concurrent.futures.ThreadPoolExecutor(num_threads) 

536 cls._threadpool_pid = pid 

537 return cls._threadpool 

538 

539 

540class OverrideResolver(Resolver): 

541 """Wraps a resolver with a mapping of overrides. 

542 

543 This can be used to make local DNS changes (e.g. for testing) 

544 without modifying system-wide settings. 

545 

546 The mapping can be in three formats:: 

547 

548 { 

549 # Hostname to host or ip 

550 "example.com": "127.0.1.1", 

551 

552 # Host+port to host+port 

553 ("login.example.com", 443): ("localhost", 1443), 

554 

555 # Host+port+address family to host+port 

556 ("login.example.com", 443, socket.AF_INET6): ("::1", 1443), 

557 } 

558 

559 .. versionchanged:: 5.0 

560 Added support for host-port-family triplets. 

561 """ 

562 

563 def initialize(self, resolver: Resolver, mapping: dict) -> None: 

564 self.resolver = resolver 

565 self.mapping = mapping 

566 

567 def close(self) -> None: 

568 self.resolver.close() 

569 

570 def resolve( 

571 self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC 

572 ) -> Awaitable[List[Tuple[int, Any]]]: 

573 if (host, port, family) in self.mapping: 

574 host, port = self.mapping[(host, port, family)] 

575 elif (host, port) in self.mapping: 

576 host, port = self.mapping[(host, port)] 

577 elif host in self.mapping: 

578 host = self.mapping[host] 

579 return self.resolver.resolve(host, port, family) 

580 

581 

582# These are the keyword arguments to ssl.wrap_socket that must be translated 

583# to their SSLContext equivalents (the other arguments are still passed 

584# to SSLContext.wrap_socket). 

585_SSL_CONTEXT_KEYWORDS = frozenset( 

586 ["ssl_version", "certfile", "keyfile", "cert_reqs", "ca_certs", "ciphers"] 

587) 

588 

589 

590def ssl_options_to_context( 

591 ssl_options: Union[Dict[str, Any], ssl.SSLContext], 

592 server_side: Optional[bool] = None, 

593) -> ssl.SSLContext: 

594 """Try to convert an ``ssl_options`` dictionary to an 

595 `~ssl.SSLContext` object. 

596 

597 The ``ssl_options`` argument may be either an `ssl.SSLContext` object or a dictionary containing 

598 keywords to be passed to ``ssl.SSLContext.wrap_socket``. This function converts the dict form 

599 to its `~ssl.SSLContext` equivalent, and may be used when a component which accepts both forms 

600 needs to upgrade to the `~ssl.SSLContext` version to use features like SNI or ALPN. 

601 

602 .. versionchanged:: 6.2 

603 

604 Added server_side argument. Omitting this argument will result in a DeprecationWarning on 

605 Python 3.10. 

606 

607 """ 

608 if isinstance(ssl_options, ssl.SSLContext): 

609 return ssl_options 

610 assert isinstance(ssl_options, dict) 

611 assert all(k in _SSL_CONTEXT_KEYWORDS for k in ssl_options), ssl_options 

612 # TODO: Now that we have the server_side argument, can we switch to 

613 # create_default_context or would that change behavior? 

614 default_version = ssl.PROTOCOL_TLS 

615 if server_side: 

616 default_version = ssl.PROTOCOL_TLS_SERVER 

617 elif server_side is not None: 

618 default_version = ssl.PROTOCOL_TLS_CLIENT 

619 context = ssl.SSLContext(ssl_options.get("ssl_version", default_version)) 

620 if "certfile" in ssl_options: 

621 context.load_cert_chain( 

622 ssl_options["certfile"], ssl_options.get("keyfile", None) 

623 ) 

624 if "cert_reqs" in ssl_options: 

625 if ssl_options["cert_reqs"] == ssl.CERT_NONE: 

626 # This may have been set automatically by PROTOCOL_TLS_CLIENT but is 

627 # incompatible with CERT_NONE so we must manually clear it. 

628 context.check_hostname = False 

629 context.verify_mode = ssl_options["cert_reqs"] 

630 if "ca_certs" in ssl_options: 

631 context.load_verify_locations(ssl_options["ca_certs"]) 

632 if "ciphers" in ssl_options: 

633 context.set_ciphers(ssl_options["ciphers"]) 

634 if hasattr(ssl, "OP_NO_COMPRESSION"): 

635 # Disable TLS compression to avoid CRIME and related attacks. 

636 # This constant depends on openssl version 1.0. 

637 # TODO: Do we need to do this ourselves or can we trust 

638 # the defaults? 

639 context.options |= ssl.OP_NO_COMPRESSION 

640 return context 

641 

642 

643def ssl_wrap_socket( 

644 socket: socket.socket, 

645 ssl_options: Union[Dict[str, Any], ssl.SSLContext], 

646 server_hostname: Optional[str] = None, 

647 server_side: Optional[bool] = None, 

648 **kwargs: Any, 

649) -> ssl.SSLSocket: 

650 """Returns an ``ssl.SSLSocket`` wrapping the given socket. 

651 

652 ``ssl_options`` may be either an `ssl.SSLContext` object or a 

653 dictionary (as accepted by `ssl_options_to_context`). Additional 

654 keyword arguments are passed to `ssl.SSLContext.wrap_socket`. 

655 

656 .. versionchanged:: 6.2 

657 

658 Added server_side argument. Omitting this argument will 

659 result in a DeprecationWarning on Python 3.10. 

660 """ 

661 context = ssl_options_to_context(ssl_options, server_side=server_side) 

662 if server_side is None: 

663 server_side = False 

664 assert ssl.HAS_SNI 

665 # TODO: add a unittest for hostname validation (python added server-side SNI support in 3.4) 

666 # In the meantime it can be manually tested with 

667 # python3 -m tornado.httpclient https://sni.velox.ch 

668 return context.wrap_socket( 

669 socket, server_hostname=server_hostname, server_side=server_side, **kwargs 

670 )