618 lines
22 KiB
Python
618 lines
22 KiB
Python
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#
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# Copyright 2011 Facebook
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Miscellaneous network utility code."""
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import concurrent.futures
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import errno
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import os
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import sys
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import socket
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import ssl
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import stat
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from tornado.concurrent import dummy_executor, run_on_executor
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from tornado.ioloop import IOLoop
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from tornado.util import Configurable, errno_from_exception
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from typing import List, Callable, Any, Type, Dict, Union, Tuple, Awaitable, Optional
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# Note that the naming of ssl.Purpose is confusing; the purpose
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# of a context is to authentiate the opposite side of the connection.
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_client_ssl_defaults = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
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_server_ssl_defaults = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
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if hasattr(ssl, "OP_NO_COMPRESSION"):
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# See netutil.ssl_options_to_context
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_client_ssl_defaults.options |= ssl.OP_NO_COMPRESSION
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_server_ssl_defaults.options |= ssl.OP_NO_COMPRESSION
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# ThreadedResolver runs getaddrinfo on a thread. If the hostname is unicode,
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# getaddrinfo attempts to import encodings.idna. If this is done at
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# module-import time, the import lock is already held by the main thread,
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# leading to deadlock. Avoid it by caching the idna encoder on the main
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# thread now.
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u"foo".encode("idna")
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# For undiagnosed reasons, 'latin1' codec may also need to be preloaded.
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u"foo".encode("latin1")
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# Default backlog used when calling sock.listen()
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_DEFAULT_BACKLOG = 128
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def bind_sockets(
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port: int,
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address: Optional[str] = None,
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family: socket.AddressFamily = socket.AF_UNSPEC,
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backlog: int = _DEFAULT_BACKLOG,
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flags: Optional[int] = None,
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reuse_port: bool = False,
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) -> List[socket.socket]:
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"""Creates listening sockets bound to the given port and address.
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Returns a list of socket objects (multiple sockets are returned if
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the given address maps to multiple IP addresses, which is most common
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for mixed IPv4 and IPv6 use).
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Address may be either an IP address or hostname. If it's a hostname,
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the server will listen on all IP addresses associated with the
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name. Address may be an empty string or None to listen on all
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available interfaces. Family may be set to either `socket.AF_INET`
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or `socket.AF_INET6` to restrict to IPv4 or IPv6 addresses, otherwise
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both will be used if available.
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The ``backlog`` argument has the same meaning as for
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`socket.listen() <socket.socket.listen>`.
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``flags`` is a bitmask of AI_* flags to `~socket.getaddrinfo`, like
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``socket.AI_PASSIVE | socket.AI_NUMERICHOST``.
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``reuse_port`` option sets ``SO_REUSEPORT`` option for every socket
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in the list. If your platform doesn't support this option ValueError will
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be raised.
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"""
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if reuse_port and not hasattr(socket, "SO_REUSEPORT"):
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raise ValueError("the platform doesn't support SO_REUSEPORT")
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sockets = []
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if address == "":
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address = None
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if not socket.has_ipv6 and family == socket.AF_UNSPEC:
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# Python can be compiled with --disable-ipv6, which causes
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# operations on AF_INET6 sockets to fail, but does not
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# automatically exclude those results from getaddrinfo
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# results.
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# http://bugs.python.org/issue16208
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family = socket.AF_INET
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if flags is None:
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flags = socket.AI_PASSIVE
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bound_port = None
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unique_addresses = set() # type: set
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for res in sorted(
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socket.getaddrinfo(address, port, family, socket.SOCK_STREAM, 0, flags),
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key=lambda x: x[0],
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):
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if res in unique_addresses:
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continue
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unique_addresses.add(res)
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af, socktype, proto, canonname, sockaddr = res
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if (
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sys.platform == "darwin"
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and address == "localhost"
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and af == socket.AF_INET6
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and sockaddr[3] != 0
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):
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# Mac OS X includes a link-local address fe80::1%lo0 in the
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# getaddrinfo results for 'localhost'. However, the firewall
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# doesn't understand that this is a local address and will
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# prompt for access (often repeatedly, due to an apparent
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# bug in its ability to remember granting access to an
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# application). Skip these addresses.
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continue
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try:
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sock = socket.socket(af, socktype, proto)
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except socket.error as e:
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if errno_from_exception(e) == errno.EAFNOSUPPORT:
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continue
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raise
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if os.name != "nt":
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try:
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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except socket.error as e:
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if errno_from_exception(e) != errno.ENOPROTOOPT:
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# Hurd doesn't support SO_REUSEADDR.
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raise
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if reuse_port:
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
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if af == socket.AF_INET6:
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# On linux, ipv6 sockets accept ipv4 too by default,
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# but this makes it impossible to bind to both
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# 0.0.0.0 in ipv4 and :: in ipv6. On other systems,
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# separate sockets *must* be used to listen for both ipv4
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# and ipv6. For consistency, always disable ipv4 on our
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# ipv6 sockets and use a separate ipv4 socket when needed.
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#
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# Python 2.x on windows doesn't have IPPROTO_IPV6.
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if hasattr(socket, "IPPROTO_IPV6"):
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sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 1)
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# automatic port allocation with port=None
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# should bind on the same port on IPv4 and IPv6
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host, requested_port = sockaddr[:2]
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if requested_port == 0 and bound_port is not None:
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sockaddr = tuple([host, bound_port] + list(sockaddr[2:]))
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sock.setblocking(False)
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try:
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sock.bind(sockaddr)
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except OSError as e:
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if (
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errno_from_exception(e) == errno.EADDRNOTAVAIL
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and address == "localhost"
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and sockaddr[0] == "::1"
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):
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# On some systems (most notably docker with default
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# configurations), ipv6 is partially disabled:
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# socket.has_ipv6 is true, we can create AF_INET6
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# sockets, and getaddrinfo("localhost", ...,
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# AF_PASSIVE) resolves to ::1, but we get an error
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# when binding.
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#
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# Swallow the error, but only for this specific case.
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# If EADDRNOTAVAIL occurs in other situations, it
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# might be a real problem like a typo in a
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# configuration.
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sock.close()
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continue
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else:
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raise
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bound_port = sock.getsockname()[1]
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sock.listen(backlog)
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sockets.append(sock)
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return sockets
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if hasattr(socket, "AF_UNIX"):
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def bind_unix_socket(
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file: str, mode: int = 0o600, backlog: int = _DEFAULT_BACKLOG
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) -> socket.socket:
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"""Creates a listening unix socket.
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If a socket with the given name already exists, it will be deleted.
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If any other file with that name exists, an exception will be
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raised.
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Returns a socket object (not a list of socket objects like
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`bind_sockets`)
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"""
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sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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try:
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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except socket.error as e:
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if errno_from_exception(e) != errno.ENOPROTOOPT:
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# Hurd doesn't support SO_REUSEADDR
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raise
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sock.setblocking(False)
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try:
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st = os.stat(file)
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except FileNotFoundError:
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pass
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else:
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if stat.S_ISSOCK(st.st_mode):
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os.remove(file)
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else:
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raise ValueError("File %s exists and is not a socket", file)
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sock.bind(file)
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os.chmod(file, mode)
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sock.listen(backlog)
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return sock
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def add_accept_handler(
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sock: socket.socket, callback: Callable[[socket.socket, Any], None]
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) -> Callable[[], None]:
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"""Adds an `.IOLoop` event handler to accept new connections on ``sock``.
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When a connection is accepted, ``callback(connection, address)`` will
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be run (``connection`` is a socket object, and ``address`` is the
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address of the other end of the connection). Note that this signature
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is different from the ``callback(fd, events)`` signature used for
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`.IOLoop` handlers.
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A callable is returned which, when called, will remove the `.IOLoop`
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event handler and stop processing further incoming connections.
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.. versionchanged:: 5.0
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The ``io_loop`` argument (deprecated since version 4.1) has been removed.
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.. versionchanged:: 5.0
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A callable is returned (``None`` was returned before).
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"""
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io_loop = IOLoop.current()
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removed = [False]
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def accept_handler(fd: socket.socket, events: int) -> None:
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# More connections may come in while we're handling callbacks;
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# to prevent starvation of other tasks we must limit the number
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# of connections we accept at a time. Ideally we would accept
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# up to the number of connections that were waiting when we
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# entered this method, but this information is not available
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# (and rearranging this method to call accept() as many times
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# as possible before running any callbacks would have adverse
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# effects on load balancing in multiprocess configurations).
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# Instead, we use the (default) listen backlog as a rough
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# heuristic for the number of connections we can reasonably
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# accept at once.
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for i in range(_DEFAULT_BACKLOG):
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if removed[0]:
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# The socket was probably closed
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return
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try:
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connection, address = sock.accept()
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except BlockingIOError:
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# EWOULDBLOCK indicates we have accepted every
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# connection that is available.
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return
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except ConnectionAbortedError:
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# ECONNABORTED indicates that there was a connection
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# but it was closed while still in the accept queue.
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# (observed on FreeBSD).
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continue
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callback(connection, address)
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def remove_handler() -> None:
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io_loop.remove_handler(sock)
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removed[0] = True
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io_loop.add_handler(sock, accept_handler, IOLoop.READ)
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return remove_handler
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def is_valid_ip(ip: str) -> bool:
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"""Returns ``True`` if the given string is a well-formed IP address.
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Supports IPv4 and IPv6.
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"""
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if not ip or "\x00" in ip:
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# getaddrinfo resolves empty strings to localhost, and truncates
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# on zero bytes.
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return False
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try:
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res = socket.getaddrinfo(
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ip, 0, socket.AF_UNSPEC, socket.SOCK_STREAM, 0, socket.AI_NUMERICHOST
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)
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return bool(res)
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except socket.gaierror as e:
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if e.args[0] == socket.EAI_NONAME:
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return False
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raise
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return True
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class Resolver(Configurable):
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"""Configurable asynchronous DNS resolver interface.
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By default, a blocking implementation is used (which simply calls
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`socket.getaddrinfo`). An alternative implementation can be
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chosen with the `Resolver.configure <.Configurable.configure>`
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class method::
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Resolver.configure('tornado.netutil.ThreadedResolver')
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The implementations of this interface included with Tornado are
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* `tornado.netutil.DefaultExecutorResolver`
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* `tornado.netutil.BlockingResolver` (deprecated)
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* `tornado.netutil.ThreadedResolver` (deprecated)
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* `tornado.netutil.OverrideResolver`
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* `tornado.platform.twisted.TwistedResolver`
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* `tornado.platform.caresresolver.CaresResolver`
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.. versionchanged:: 5.0
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The default implementation has changed from `BlockingResolver` to
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`DefaultExecutorResolver`.
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"""
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@classmethod
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def configurable_base(cls) -> Type["Resolver"]:
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return Resolver
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@classmethod
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def configurable_default(cls) -> Type["Resolver"]:
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return DefaultExecutorResolver
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def resolve(
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self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
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) -> Awaitable[List[Tuple[int, Any]]]:
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"""Resolves an address.
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The ``host`` argument is a string which may be a hostname or a
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literal IP address.
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Returns a `.Future` whose result is a list of (family,
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address) pairs, where address is a tuple suitable to pass to
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`socket.connect <socket.socket.connect>` (i.e. a ``(host,
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port)`` pair for IPv4; additional fields may be present for
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IPv6). If a ``callback`` is passed, it will be run with the
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result as an argument when it is complete.
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:raises IOError: if the address cannot be resolved.
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.. versionchanged:: 4.4
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Standardized all implementations to raise `IOError`.
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.. versionchanged:: 6.0 The ``callback`` argument was removed.
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Use the returned awaitable object instead.
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"""
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raise NotImplementedError()
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def close(self) -> None:
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"""Closes the `Resolver`, freeing any resources used.
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.. versionadded:: 3.1
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"""
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pass
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def _resolve_addr(
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host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
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) -> List[Tuple[int, Any]]:
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# On Solaris, getaddrinfo fails if the given port is not found
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# in /etc/services and no socket type is given, so we must pass
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# one here. The socket type used here doesn't seem to actually
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# matter (we discard the one we get back in the results),
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# so the addresses we return should still be usable with SOCK_DGRAM.
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addrinfo = socket.getaddrinfo(host, port, family, socket.SOCK_STREAM)
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results = []
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for fam, socktype, proto, canonname, address in addrinfo:
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results.append((fam, address))
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return results # type: ignore
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class DefaultExecutorResolver(Resolver):
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"""Resolver implementation using `.IOLoop.run_in_executor`.
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.. versionadded:: 5.0
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"""
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async def resolve(
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self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
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) -> List[Tuple[int, Any]]:
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result = await IOLoop.current().run_in_executor(
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None, _resolve_addr, host, port, family
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)
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return result
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class ExecutorResolver(Resolver):
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"""Resolver implementation using a `concurrent.futures.Executor`.
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Use this instead of `ThreadedResolver` when you require additional
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control over the executor being used.
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The executor will be shut down when the resolver is closed unless
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``close_resolver=False``; use this if you want to reuse the same
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executor elsewhere.
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.. versionchanged:: 5.0
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The ``io_loop`` argument (deprecated since version 4.1) has been removed.
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.. deprecated:: 5.0
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The default `Resolver` now uses `.IOLoop.run_in_executor`; use that instead
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of this class.
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"""
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def initialize(
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self,
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executor: Optional[concurrent.futures.Executor] = None,
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close_executor: bool = True,
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) -> None:
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self.io_loop = IOLoop.current()
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if executor is not None:
|
||
|
self.executor = executor
|
||
|
self.close_executor = close_executor
|
||
|
else:
|
||
|
self.executor = dummy_executor
|
||
|
self.close_executor = False
|
||
|
|
||
|
def close(self) -> None:
|
||
|
if self.close_executor:
|
||
|
self.executor.shutdown()
|
||
|
self.executor = None # type: ignore
|
||
|
|
||
|
@run_on_executor
|
||
|
def resolve(
|
||
|
self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
|
||
|
) -> List[Tuple[int, Any]]:
|
||
|
return _resolve_addr(host, port, family)
|
||
|
|
||
|
|
||
|
class BlockingResolver(ExecutorResolver):
|
||
|
"""Default `Resolver` implementation, using `socket.getaddrinfo`.
|
||
|
|
||
|
The `.IOLoop` will be blocked during the resolution, although the
|
||
|
callback will not be run until the next `.IOLoop` iteration.
|
||
|
|
||
|
.. deprecated:: 5.0
|
||
|
The default `Resolver` now uses `.IOLoop.run_in_executor`; use that instead
|
||
|
of this class.
|
||
|
"""
|
||
|
|
||
|
def initialize(self) -> None: # type: ignore
|
||
|
super().initialize()
|
||
|
|
||
|
|
||
|
class ThreadedResolver(ExecutorResolver):
|
||
|
"""Multithreaded non-blocking `Resolver` implementation.
|
||
|
|
||
|
Requires the `concurrent.futures` package to be installed
|
||
|
(available in the standard library since Python 3.2,
|
||
|
installable with ``pip install futures`` in older versions).
|
||
|
|
||
|
The thread pool size can be configured with::
|
||
|
|
||
|
Resolver.configure('tornado.netutil.ThreadedResolver',
|
||
|
num_threads=10)
|
||
|
|
||
|
.. versionchanged:: 3.1
|
||
|
All ``ThreadedResolvers`` share a single thread pool, whose
|
||
|
size is set by the first one to be created.
|
||
|
|
||
|
.. deprecated:: 5.0
|
||
|
The default `Resolver` now uses `.IOLoop.run_in_executor`; use that instead
|
||
|
of this class.
|
||
|
"""
|
||
|
|
||
|
_threadpool = None # type: ignore
|
||
|
_threadpool_pid = None # type: int
|
||
|
|
||
|
def initialize(self, num_threads: int = 10) -> None: # type: ignore
|
||
|
threadpool = ThreadedResolver._create_threadpool(num_threads)
|
||
|
super().initialize(executor=threadpool, close_executor=False)
|
||
|
|
||
|
@classmethod
|
||
|
def _create_threadpool(
|
||
|
cls, num_threads: int
|
||
|
) -> concurrent.futures.ThreadPoolExecutor:
|
||
|
pid = os.getpid()
|
||
|
if cls._threadpool_pid != pid:
|
||
|
# Threads cannot survive after a fork, so if our pid isn't what it
|
||
|
# was when we created the pool then delete it.
|
||
|
cls._threadpool = None
|
||
|
if cls._threadpool is None:
|
||
|
cls._threadpool = concurrent.futures.ThreadPoolExecutor(num_threads)
|
||
|
cls._threadpool_pid = pid
|
||
|
return cls._threadpool
|
||
|
|
||
|
|
||
|
class OverrideResolver(Resolver):
|
||
|
"""Wraps a resolver with a mapping of overrides.
|
||
|
|
||
|
This can be used to make local DNS changes (e.g. for testing)
|
||
|
without modifying system-wide settings.
|
||
|
|
||
|
The mapping can be in three formats::
|
||
|
|
||
|
{
|
||
|
# Hostname to host or ip
|
||
|
"example.com": "127.0.1.1",
|
||
|
|
||
|
# Host+port to host+port
|
||
|
("login.example.com", 443): ("localhost", 1443),
|
||
|
|
||
|
# Host+port+address family to host+port
|
||
|
("login.example.com", 443, socket.AF_INET6): ("::1", 1443),
|
||
|
}
|
||
|
|
||
|
.. versionchanged:: 5.0
|
||
|
Added support for host-port-family triplets.
|
||
|
"""
|
||
|
|
||
|
def initialize(self, resolver: Resolver, mapping: dict) -> None:
|
||
|
self.resolver = resolver
|
||
|
self.mapping = mapping
|
||
|
|
||
|
def close(self) -> None:
|
||
|
self.resolver.close()
|
||
|
|
||
|
def resolve(
|
||
|
self, host: str, port: int, family: socket.AddressFamily = socket.AF_UNSPEC
|
||
|
) -> Awaitable[List[Tuple[int, Any]]]:
|
||
|
if (host, port, family) in self.mapping:
|
||
|
host, port = self.mapping[(host, port, family)]
|
||
|
elif (host, port) in self.mapping:
|
||
|
host, port = self.mapping[(host, port)]
|
||
|
elif host in self.mapping:
|
||
|
host = self.mapping[host]
|
||
|
return self.resolver.resolve(host, port, family)
|
||
|
|
||
|
|
||
|
# These are the keyword arguments to ssl.wrap_socket that must be translated
|
||
|
# to their SSLContext equivalents (the other arguments are still passed
|
||
|
# to SSLContext.wrap_socket).
|
||
|
_SSL_CONTEXT_KEYWORDS = frozenset(
|
||
|
["ssl_version", "certfile", "keyfile", "cert_reqs", "ca_certs", "ciphers"]
|
||
|
)
|
||
|
|
||
|
|
||
|
def ssl_options_to_context(
|
||
|
ssl_options: Union[Dict[str, Any], ssl.SSLContext]
|
||
|
) -> ssl.SSLContext:
|
||
|
"""Try to convert an ``ssl_options`` dictionary to an
|
||
|
`~ssl.SSLContext` object.
|
||
|
|
||
|
The ``ssl_options`` dictionary contains keywords to be passed to
|
||
|
`ssl.wrap_socket`. In Python 2.7.9+, `ssl.SSLContext` objects can
|
||
|
be used instead. This function converts the dict form to its
|
||
|
`~ssl.SSLContext` equivalent, and may be used when a component which
|
||
|
accepts both forms needs to upgrade to the `~ssl.SSLContext` version
|
||
|
to use features like SNI or NPN.
|
||
|
"""
|
||
|
if isinstance(ssl_options, ssl.SSLContext):
|
||
|
return ssl_options
|
||
|
assert isinstance(ssl_options, dict)
|
||
|
assert all(k in _SSL_CONTEXT_KEYWORDS for k in ssl_options), ssl_options
|
||
|
# Can't use create_default_context since this interface doesn't
|
||
|
# tell us client vs server.
|
||
|
context = ssl.SSLContext(ssl_options.get("ssl_version", ssl.PROTOCOL_SSLv23))
|
||
|
if "certfile" in ssl_options:
|
||
|
context.load_cert_chain(
|
||
|
ssl_options["certfile"], ssl_options.get("keyfile", None)
|
||
|
)
|
||
|
if "cert_reqs" in ssl_options:
|
||
|
context.verify_mode = ssl_options["cert_reqs"]
|
||
|
if "ca_certs" in ssl_options:
|
||
|
context.load_verify_locations(ssl_options["ca_certs"])
|
||
|
if "ciphers" in ssl_options:
|
||
|
context.set_ciphers(ssl_options["ciphers"])
|
||
|
if hasattr(ssl, "OP_NO_COMPRESSION"):
|
||
|
# Disable TLS compression to avoid CRIME and related attacks.
|
||
|
# This constant depends on openssl version 1.0.
|
||
|
# TODO: Do we need to do this ourselves or can we trust
|
||
|
# the defaults?
|
||
|
context.options |= ssl.OP_NO_COMPRESSION
|
||
|
return context
|
||
|
|
||
|
|
||
|
def ssl_wrap_socket(
|
||
|
socket: socket.socket,
|
||
|
ssl_options: Union[Dict[str, Any], ssl.SSLContext],
|
||
|
server_hostname: Optional[str] = None,
|
||
|
**kwargs: Any
|
||
|
) -> ssl.SSLSocket:
|
||
|
"""Returns an ``ssl.SSLSocket`` wrapping the given socket.
|
||
|
|
||
|
``ssl_options`` may be either an `ssl.SSLContext` object or a
|
||
|
dictionary (as accepted by `ssl_options_to_context`). Additional
|
||
|
keyword arguments are passed to ``wrap_socket`` (either the
|
||
|
`~ssl.SSLContext` method or the `ssl` module function as
|
||
|
appropriate).
|
||
|
"""
|
||
|
context = ssl_options_to_context(ssl_options)
|
||
|
if ssl.HAS_SNI:
|
||
|
# In python 3.4, wrap_socket only accepts the server_hostname
|
||
|
# argument if HAS_SNI is true.
|
||
|
# TODO: add a unittest (python added server-side SNI support in 3.4)
|
||
|
# In the meantime it can be manually tested with
|
||
|
# python3 -m tornado.httpclient https://sni.velox.ch
|
||
|
return context.wrap_socket(socket, server_hostname=server_hostname, **kwargs)
|
||
|
else:
|
||
|
return context.wrap_socket(socket, **kwargs)
|