|
|
# "High-level" networking interface
|
|
|
|
|
|
import errno
|
|
|
from contextlib import contextmanager
|
|
|
|
|
|
import trio
|
|
|
from . import socket as tsocket
|
|
|
from ._util import ConflictDetector, Final
|
|
|
from .abc import HalfCloseableStream, Listener
|
|
|
|
|
|
# XX TODO: this number was picked arbitrarily. We should do experiments to
|
|
|
# tune it. (Or make it dynamic -- one idea is to start small and increase it
|
|
|
# if we observe single reads filling up the whole buffer, at least within some
|
|
|
# limits.)
|
|
|
DEFAULT_RECEIVE_SIZE = 65536
|
|
|
|
|
|
_closed_stream_errnos = {
|
|
|
# Unix
|
|
|
errno.EBADF,
|
|
|
# Windows
|
|
|
errno.ENOTSOCK,
|
|
|
}
|
|
|
|
|
|
|
|
|
@contextmanager
|
|
|
def _translate_socket_errors_to_stream_errors():
|
|
|
try:
|
|
|
yield
|
|
|
except OSError as exc:
|
|
|
if exc.errno in _closed_stream_errnos:
|
|
|
raise trio.ClosedResourceError("this socket was already closed") from None
|
|
|
else:
|
|
|
raise trio.BrokenResourceError(
|
|
|
"socket connection broken: {}".format(exc)
|
|
|
) from exc
|
|
|
|
|
|
|
|
|
class SocketStream(HalfCloseableStream, metaclass=Final):
|
|
|
"""An implementation of the :class:`trio.abc.HalfCloseableStream`
|
|
|
interface based on a raw network socket.
|
|
|
|
|
|
Args:
|
|
|
socket: The Trio socket object to wrap. Must have type ``SOCK_STREAM``,
|
|
|
and be connected.
|
|
|
|
|
|
By default for TCP sockets, :class:`SocketStream` enables ``TCP_NODELAY``,
|
|
|
and (on platforms where it's supported) enables ``TCP_NOTSENT_LOWAT`` with
|
|
|
a reasonable buffer size (currently 16 KiB) – see `issue #72
|
|
|
<https://github.com/python-trio/trio/issues/72>`__ for discussion. You can
|
|
|
of course override these defaults by calling :meth:`setsockopt`.
|
|
|
|
|
|
Once a :class:`SocketStream` object is constructed, it implements the full
|
|
|
:class:`trio.abc.HalfCloseableStream` interface. In addition, it provides
|
|
|
a few extra features:
|
|
|
|
|
|
.. attribute:: socket
|
|
|
|
|
|
The Trio socket object that this stream wraps.
|
|
|
|
|
|
"""
|
|
|
|
|
|
def __init__(self, socket):
|
|
|
if not isinstance(socket, tsocket.SocketType):
|
|
|
raise TypeError("SocketStream requires a Trio socket object")
|
|
|
if socket.type != tsocket.SOCK_STREAM:
|
|
|
raise ValueError("SocketStream requires a SOCK_STREAM socket")
|
|
|
|
|
|
self.socket = socket
|
|
|
self._send_conflict_detector = ConflictDetector(
|
|
|
"another task is currently sending data on this SocketStream"
|
|
|
)
|
|
|
|
|
|
# Socket defaults:
|
|
|
|
|
|
# Not supported on e.g. unix domain sockets
|
|
|
try:
|
|
|
self.setsockopt(tsocket.IPPROTO_TCP, tsocket.TCP_NODELAY, True)
|
|
|
except OSError:
|
|
|
pass
|
|
|
|
|
|
if hasattr(tsocket, "TCP_NOTSENT_LOWAT"):
|
|
|
try:
|
|
|
# 16 KiB is pretty arbitrary and could probably do with some
|
|
|
# tuning. (Apple is also setting this by default in CFNetwork
|
|
|
# apparently -- I'm curious what value they're using, though I
|
|
|
# couldn't find it online trivially. CFNetwork-129.20 source
|
|
|
# has no mentions of TCP_NOTSENT_LOWAT. This presentation says
|
|
|
# "typically 8 kilobytes":
|
|
|
# http://devstreaming.apple.com/videos/wwdc/2015/719ui2k57m/719/719_your_app_and_next_generation_networks.pdf?dl=1
|
|
|
# ). The theory is that you want it to be bandwidth *
|
|
|
# rescheduling interval.
|
|
|
self.setsockopt(tsocket.IPPROTO_TCP, tsocket.TCP_NOTSENT_LOWAT, 2**14)
|
|
|
except OSError:
|
|
|
pass
|
|
|
|
|
|
async def send_all(self, data):
|
|
|
if self.socket.did_shutdown_SHUT_WR:
|
|
|
raise trio.ClosedResourceError("can't send data after sending EOF")
|
|
|
with self._send_conflict_detector:
|
|
|
with _translate_socket_errors_to_stream_errors():
|
|
|
with memoryview(data) as data:
|
|
|
if not data:
|
|
|
if self.socket.fileno() == -1:
|
|
|
raise trio.ClosedResourceError("socket was already closed")
|
|
|
await trio.lowlevel.checkpoint()
|
|
|
return
|
|
|
total_sent = 0
|
|
|
while total_sent < len(data):
|
|
|
with data[total_sent:] as remaining:
|
|
|
sent = await self.socket.send(remaining)
|
|
|
total_sent += sent
|
|
|
|
|
|
async def wait_send_all_might_not_block(self):
|
|
|
with self._send_conflict_detector:
|
|
|
if self.socket.fileno() == -1:
|
|
|
raise trio.ClosedResourceError
|
|
|
with _translate_socket_errors_to_stream_errors():
|
|
|
await self.socket.wait_writable()
|
|
|
|
|
|
async def send_eof(self):
|
|
|
with self._send_conflict_detector:
|
|
|
await trio.lowlevel.checkpoint()
|
|
|
# On macOS, calling shutdown a second time raises ENOTCONN, but
|
|
|
# send_eof needs to be idempotent.
|
|
|
if self.socket.did_shutdown_SHUT_WR:
|
|
|
return
|
|
|
with _translate_socket_errors_to_stream_errors():
|
|
|
self.socket.shutdown(tsocket.SHUT_WR)
|
|
|
|
|
|
async def receive_some(self, max_bytes=None):
|
|
|
if max_bytes is None:
|
|
|
max_bytes = DEFAULT_RECEIVE_SIZE
|
|
|
if max_bytes < 1:
|
|
|
raise ValueError("max_bytes must be >= 1")
|
|
|
with _translate_socket_errors_to_stream_errors():
|
|
|
return await self.socket.recv(max_bytes)
|
|
|
|
|
|
async def aclose(self):
|
|
|
self.socket.close()
|
|
|
await trio.lowlevel.checkpoint()
|
|
|
|
|
|
# __aenter__, __aexit__ inherited from HalfCloseableStream are OK
|
|
|
|
|
|
def setsockopt(self, level, option, value):
|
|
|
"""Set an option on the underlying socket.
|
|
|
|
|
|
See :meth:`socket.socket.setsockopt` for details.
|
|
|
|
|
|
"""
|
|
|
return self.socket.setsockopt(level, option, value)
|
|
|
|
|
|
def getsockopt(self, level, option, buffersize=0):
|
|
|
"""Check the current value of an option on the underlying socket.
|
|
|
|
|
|
See :meth:`socket.socket.getsockopt` for details.
|
|
|
|
|
|
"""
|
|
|
# This is to work around
|
|
|
# https://bitbucket.org/pypy/pypy/issues/2561
|
|
|
# We should be able to drop it when the next PyPy3 beta is released.
|
|
|
if buffersize == 0:
|
|
|
return self.socket.getsockopt(level, option)
|
|
|
else:
|
|
|
return self.socket.getsockopt(level, option, buffersize)
|
|
|
|
|
|
|
|
|
################################################################
|
|
|
# SocketListener
|
|
|
################################################################
|
|
|
|
|
|
# Accept error handling
|
|
|
# =====================
|
|
|
#
|
|
|
# Literature review
|
|
|
# -----------------
|
|
|
#
|
|
|
# Here's a list of all the possible errors that accept() can return, according
|
|
|
# to the POSIX spec or the Linux, FreeBSD, macOS, and Windows docs:
|
|
|
#
|
|
|
# Can't happen with a Trio socket:
|
|
|
# - EAGAIN/(WSA)EWOULDBLOCK
|
|
|
# - EINTR
|
|
|
# - WSANOTINITIALISED
|
|
|
# - WSAEINPROGRESS: a blocking call is already in progress
|
|
|
# - WSAEINTR: someone called WSACancelBlockingCall, but we don't make blocking
|
|
|
# calls in the first place
|
|
|
#
|
|
|
# Something is wrong with our call:
|
|
|
# - EBADF: not a file descriptor
|
|
|
# - (WSA)EINVAL: socket isn't listening, or (Linux, BSD) bad flags
|
|
|
# - (WSA)ENOTSOCK: not a socket
|
|
|
# - (WSA)EOPNOTSUPP: this kind of socket doesn't support accept
|
|
|
# - (Linux, FreeBSD, Windows) EFAULT: the sockaddr pointer points to readonly
|
|
|
# memory
|
|
|
#
|
|
|
# Something is wrong with the environment:
|
|
|
# - (WSA)EMFILE: this process hit its fd limit
|
|
|
# - ENFILE: the system hit its fd limit
|
|
|
# - (WSA)ENOBUFS, ENOMEM: unspecified memory problems
|
|
|
#
|
|
|
# Something is wrong with the connection we were going to accept. There's a
|
|
|
# ton of variability between systems here:
|
|
|
# - ECONNABORTED: documented everywhere, but apparently only the BSDs do this
|
|
|
# (signals a connection was closed/reset before being accepted)
|
|
|
# - EPROTO: unspecified protocol error
|
|
|
# - (Linux) EPERM: firewall rule prevented connection
|
|
|
# - (Linux) ENETDOWN, EPROTO, ENOPROTOOPT, EHOSTDOWN, ENONET, EHOSTUNREACH,
|
|
|
# EOPNOTSUPP, ENETUNREACH, ENOSR, ESOCKTNOSUPPORT, EPROTONOSUPPORT,
|
|
|
# ETIMEDOUT, ... or any other error that the socket could give, because
|
|
|
# apparently if an error happens on a connection before it's accept()ed,
|
|
|
# Linux will report that error from accept().
|
|
|
# - (Windows) WSAECONNRESET, WSAENETDOWN
|
|
|
#
|
|
|
#
|
|
|
# Code review
|
|
|
# -----------
|
|
|
#
|
|
|
# What do other libraries do?
|
|
|
#
|
|
|
# Twisted on Unix or when using nonblocking I/O on Windows:
|
|
|
# - ignores EPERM, with comment about Linux firewalls
|
|
|
# - logs and ignores EMFILE, ENOBUFS, ENFILE, ENOMEM, ECONNABORTED
|
|
|
# Comment notes that ECONNABORTED is a BSDism and that Linux returns the
|
|
|
# socket before having it fail, and macOS just silently discards it.
|
|
|
# - other errors are raised, which is logged + kills the socket
|
|
|
# ref: src/twisted/internet/tcp.py, Port.doRead
|
|
|
#
|
|
|
# Twisted using IOCP on Windows:
|
|
|
# - logs and ignores all errors
|
|
|
# ref: src/twisted/internet/iocpreactor/tcp.py, Port.handleAccept
|
|
|
#
|
|
|
# Tornado:
|
|
|
# - ignore ECONNABORTED (comments notes that it was observed on FreeBSD)
|
|
|
# - everything else raised, but all this does (by default) is cause it to be
|
|
|
# logged and then ignored
|
|
|
# (ref: tornado/netutil.py, tornado/ioloop.py)
|
|
|
#
|
|
|
# libuv on Unix:
|
|
|
# - ignores ECONNABORTED
|
|
|
# - does a "trick" for EMFILE or ENFILE
|
|
|
# - all other errors passed to the connection_cb to be handled
|
|
|
# (ref: src/unix/stream.c:uv__server_io, uv__emfile_trick)
|
|
|
#
|
|
|
# libuv on Windows:
|
|
|
# src/win/tcp.c:uv_tcp_queue_accept
|
|
|
# this calls AcceptEx, and then arranges to call:
|
|
|
# src/win/tcp.c:uv_process_tcp_accept_req
|
|
|
# this gets the result from AcceptEx. If the original AcceptEx call failed,
|
|
|
# then "we stop accepting connections and report this error to the
|
|
|
# connection callback". I think this is for things like ENOTSOCK. If
|
|
|
# AcceptEx successfully queues an overlapped operation, and then that
|
|
|
# reports an error, it's just discarded.
|
|
|
#
|
|
|
# asyncio, selector mode:
|
|
|
# - ignores EWOULDBLOCK, EINTR, ECONNABORTED
|
|
|
# - on EMFILE, ENFILE, ENOBUFS, ENOMEM, logs an error and then disables the
|
|
|
# listening loop for 1 second
|
|
|
# - everything else raises, but then the event loop just logs and ignores it
|
|
|
# (selector_events.py: BaseSelectorEventLoop._accept_connection)
|
|
|
#
|
|
|
#
|
|
|
# What should we do?
|
|
|
# ------------------
|
|
|
#
|
|
|
# When accept() returns an error, we can either ignore it or raise it.
|
|
|
#
|
|
|
# We have a long list of errors that should be ignored, and a long list of
|
|
|
# errors that should be raised. The big question is what to do with an error
|
|
|
# that isn't on either list. On Linux apparently you can get nearly arbitrary
|
|
|
# errors from accept() and they should be ignored, because it just indicates a
|
|
|
# socket that crashed before it began, and there isn't really anything to be
|
|
|
# done about this, plus on other platforms you may not get any indication at
|
|
|
# all, so programs have to tolerate not getting any indication too. OTOH if we
|
|
|
# get an unexpected error then it could indicate something arbitrarily bad --
|
|
|
# after all, it's unexpected.
|
|
|
#
|
|
|
# Given that we know that other libraries seem to be getting along fine with a
|
|
|
# fairly minimal list of errors to ignore, I think we'll be OK if we write
|
|
|
# down that list and then raise on everything else.
|
|
|
#
|
|
|
# The other question is what to do about the capacity problem errors: EMFILE,
|
|
|
# ENFILE, ENOBUFS, ENOMEM. Just flat out ignoring these is clearly not optimal
|
|
|
# -- at the very least you want to log them, and probably you want to take
|
|
|
# some remedial action. And if we ignore them then it prevents higher levels
|
|
|
# from doing anything clever with them. So we raise them.
|
|
|
|
|
|
_ignorable_accept_errno_names = [
|
|
|
# Linux can do this when the a connection is denied by the firewall
|
|
|
"EPERM",
|
|
|
# BSDs with an early close/reset
|
|
|
"ECONNABORTED",
|
|
|
# All the other miscellany noted above -- may not happen in practice, but
|
|
|
# whatever.
|
|
|
"EPROTO",
|
|
|
"ENETDOWN",
|
|
|
"ENOPROTOOPT",
|
|
|
"EHOSTDOWN",
|
|
|
"ENONET",
|
|
|
"EHOSTUNREACH",
|
|
|
"EOPNOTSUPP",
|
|
|
"ENETUNREACH",
|
|
|
"ENOSR",
|
|
|
"ESOCKTNOSUPPORT",
|
|
|
"EPROTONOSUPPORT",
|
|
|
"ETIMEDOUT",
|
|
|
"ECONNRESET",
|
|
|
]
|
|
|
|
|
|
# Not all errnos are defined on all platforms
|
|
|
_ignorable_accept_errnos = set()
|
|
|
for name in _ignorable_accept_errno_names:
|
|
|
try:
|
|
|
_ignorable_accept_errnos.add(getattr(errno, name))
|
|
|
except AttributeError:
|
|
|
pass
|
|
|
|
|
|
|
|
|
class SocketListener(Listener[SocketStream], metaclass=Final):
|
|
|
"""A :class:`~trio.abc.Listener` that uses a listening socket to accept
|
|
|
incoming connections as :class:`SocketStream` objects.
|
|
|
|
|
|
Args:
|
|
|
socket: The Trio socket object to wrap. Must have type ``SOCK_STREAM``,
|
|
|
and be listening.
|
|
|
|
|
|
Note that the :class:`SocketListener` "takes ownership" of the given
|
|
|
socket; closing the :class:`SocketListener` will also close the socket.
|
|
|
|
|
|
.. attribute:: socket
|
|
|
|
|
|
The Trio socket object that this stream wraps.
|
|
|
|
|
|
"""
|
|
|
|
|
|
def __init__(self, socket):
|
|
|
if not isinstance(socket, tsocket.SocketType):
|
|
|
raise TypeError("SocketListener requires a Trio socket object")
|
|
|
if socket.type != tsocket.SOCK_STREAM:
|
|
|
raise ValueError("SocketListener requires a SOCK_STREAM socket")
|
|
|
try:
|
|
|
listening = socket.getsockopt(tsocket.SOL_SOCKET, tsocket.SO_ACCEPTCONN)
|
|
|
except OSError:
|
|
|
# SO_ACCEPTCONN fails on macOS; we just have to trust the user.
|
|
|
pass
|
|
|
else:
|
|
|
if not listening:
|
|
|
raise ValueError("SocketListener requires a listening socket")
|
|
|
|
|
|
self.socket = socket
|
|
|
|
|
|
async def accept(self):
|
|
|
"""Accept an incoming connection.
|
|
|
|
|
|
Returns:
|
|
|
:class:`SocketStream`
|
|
|
|
|
|
Raises:
|
|
|
OSError: if the underlying call to ``accept`` raises an unexpected
|
|
|
error.
|
|
|
ClosedResourceError: if you already closed the socket.
|
|
|
|
|
|
This method handles routine errors like ``ECONNABORTED``, but passes
|
|
|
other errors on to its caller. In particular, it does *not* make any
|
|
|
special effort to handle resource exhaustion errors like ``EMFILE``,
|
|
|
``ENFILE``, ``ENOBUFS``, ``ENOMEM``.
|
|
|
|
|
|
"""
|
|
|
while True:
|
|
|
try:
|
|
|
sock, _ = await self.socket.accept()
|
|
|
except OSError as exc:
|
|
|
if exc.errno in _closed_stream_errnos:
|
|
|
raise trio.ClosedResourceError
|
|
|
if exc.errno not in _ignorable_accept_errnos:
|
|
|
raise
|
|
|
else:
|
|
|
return SocketStream(sock)
|
|
|
|
|
|
async def aclose(self):
|
|
|
"""Close this listener and its underlying socket."""
|
|
|
self.socket.close()
|
|
|
await trio.lowlevel.checkpoint()
|