diff options
Diffstat (limited to 'Lib/socket.py')
| -rw-r--r-- | Lib/socket.py | 87 |
1 files changed, 85 insertions, 2 deletions
diff --git a/Lib/socket.py b/Lib/socket.py index 772b9e1..2e51cd1 100644 --- a/Lib/socket.py +++ b/Lib/socket.py @@ -60,8 +60,8 @@ EBADF = getattr(errno, 'EBADF', 9) EAGAIN = getattr(errno, 'EAGAIN', 11) EWOULDBLOCK = getattr(errno, 'EWOULDBLOCK', 11) -__all__ = ["fromfd", "getfqdn", "create_connection", - "AddressFamily", "SocketKind"] +__all__ = ["fromfd", "getfqdn", "create_connection", "create_server", + "has_dualstack_ipv6", "AddressFamily", "SocketKind"] __all__.extend(os._get_exports_list(_socket)) # Set up the socket.AF_* socket.SOCK_* constants as members of IntEnums for @@ -728,6 +728,89 @@ def create_connection(address, timeout=_GLOBAL_DEFAULT_TIMEOUT, else: raise error("getaddrinfo returns an empty list") + +def has_dualstack_ipv6(): + """Return True if the platform supports creating a SOCK_STREAM socket + which can handle both AF_INET and AF_INET6 (IPv4 / IPv6) connections. + """ + if not has_ipv6 \ + or not hasattr(_socket, 'IPPROTO_IPV6') \ + or not hasattr(_socket, 'IPV6_V6ONLY'): + return False + try: + with socket(AF_INET6, SOCK_STREAM) as sock: + sock.setsockopt(IPPROTO_IPV6, IPV6_V6ONLY, 0) + return True + except error: + return False + + +def create_server(address, *, family=AF_INET, backlog=0, reuse_port=False, + dualstack_ipv6=False): + """Convenience function which creates a SOCK_STREAM type socket + bound to *address* (a 2-tuple (host, port)) and return the socket + object. + + *family* should be either AF_INET or AF_INET6. + *backlog* is the queue size passed to socket.listen(). + *reuse_port* dictates whether to use the SO_REUSEPORT socket option. + *dualstack_ipv6*: if true and the platform supports it, it will + create an AF_INET6 socket able to accept both IPv4 or IPv6 + connections. When false it will explicitly disable this option on + platforms that enable it by default (e.g. Linux). + + >>> with create_server((None, 8000)) as server: + ... while True: + ... conn, addr = server.accept() + ... # handle new connection + """ + if reuse_port and not hasattr(_socket, "SO_REUSEPORT"): + raise ValueError("SO_REUSEPORT not supported on this platform") + if dualstack_ipv6: + if not has_dualstack_ipv6(): + raise ValueError("dualstack_ipv6 not supported on this platform") + if family != AF_INET6: + raise ValueError("dualstack_ipv6 requires AF_INET6 family") + sock = socket(family, SOCK_STREAM) + try: + # Note about Windows. We don't set SO_REUSEADDR because: + # 1) It's unnecessary: bind() will succeed even in case of a + # previous closed socket on the same address and still in + # TIME_WAIT state. + # 2) If set, another socket is free to bind() on the same + # address, effectively preventing this one from accepting + # connections. Also, it may set the process in a state where + # it'll no longer respond to any signals or graceful kills. + # See: msdn2.microsoft.com/en-us/library/ms740621(VS.85).aspx + if os.name not in ('nt', 'cygwin') and \ + hasattr(_socket, 'SO_REUSEADDR'): + try: + sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) + except error: + # Fail later on bind(), for platforms which may not + # support this option. + pass + if reuse_port: + sock.setsockopt(SOL_SOCKET, SO_REUSEPORT, 1) + if has_ipv6 and family == AF_INET6: + if dualstack_ipv6: + sock.setsockopt(IPPROTO_IPV6, IPV6_V6ONLY, 0) + elif hasattr(_socket, "IPV6_V6ONLY") and \ + hasattr(_socket, "IPPROTO_IPV6"): + sock.setsockopt(IPPROTO_IPV6, IPV6_V6ONLY, 1) + try: + sock.bind(address) + except error as err: + msg = '%s (while attempting to bind on address %r)' % \ + (err.strerror, address) + raise error(err.errno, msg) from None + sock.listen(backlog) + return sock + except error: + sock.close() + raise + + def getaddrinfo(host, port, family=0, type=0, proto=0, flags=0): """Resolve host and port into list of address info entries. |