From 1ede182eada408c3f1551bc2ccf86043c02e4a1c Mon Sep 17 00:00:00 2001 From: "J. Nick Koston" Date: Sun, 21 Mar 2021 09:20:16 -1000 Subject: [PATCH] Use a single socket for InterfaceChoice.Default When using multiple sockets with multi-cast, the outgoing socket's responses could be read back on the incoming socket, which leads to duplicate processing and could fill up the incoming buffer before it could be processed. This behavior manifested with error similar to `OSError: [Errno 105] No buffer space available` By using a single socket with InterfaceChoice.Default we avoid this case. --- zeroconf/__init__.py | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-) diff --git a/zeroconf/__init__.py b/zeroconf/__init__.py index dbeef01b..e21c3e80 100644 --- a/zeroconf/__init__.py +++ b/zeroconf/__init__.py @@ -2255,8 +2255,7 @@ def new_socket( def add_multicast_member( listen_socket: socket.socket, interface: Union[str, Tuple[Tuple[str, int, int], int]], - apple_p2p: bool = False, -) -> Optional[socket.socket]: +) -> None: # This is based on assumptions in normalize_interface_choice is_v6 = isinstance(interface, tuple) err_einval = {errno.EINVAL} @@ -2293,6 +2292,12 @@ def add_multicast_member( else: raise + +def new_respond_socket( + interface: Union[str, Tuple[Tuple[str, int, int], int]], + apple_p2p: bool = False, +) -> Optional[socket.socket]: + is_v6 = isinstance(interface, tuple) respond_socket = new_socket( ip_version=(IPVersion.V6Only if is_v6 else IPVersion.V4Only), apple_p2p=apple_p2p, @@ -2300,6 +2305,7 @@ def add_multicast_member( ) log.debug('Configuring socket %s with multicast interface %s', respond_socket, interface) if is_v6: + iface_bin = struct.pack('@I', cast(int, interface[1])) respond_socket.setsockopt(_IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, iface_bin) else: respond_socket.setsockopt( @@ -2321,11 +2327,19 @@ def create_sockets( normalized_interfaces = normalize_interface_choice(interfaces, ip_version) + # If we are using InterfaceChoice.Default we can use + # a single socket to listen and respond. + if not unicast and interfaces is InterfaceChoice.Default: + for i in normalized_interfaces: + add_multicast_member(cast(socket.socket, listen_socket), i) + return listen_socket, [listen_socket] + respond_sockets = [] for i in normalized_interfaces: if not unicast: - respond_socket = add_multicast_member(cast(socket.socket, listen_socket), i, apple_p2p=apple_p2p) + add_multicast_member(cast(socket.socket, listen_socket), i) + respond_socket = new_respond_socket(i, apple_p2p=apple_p2p) else: respond_socket = new_socket( port=0, @@ -2494,6 +2508,7 @@ def __init__( interfaces, unicast, ip_version, apple_p2p=apple_p2p ) log.debug('Listen socket %s, respond sockets %s', self._listen_socket, self._respond_sockets) + self.multi_socket = unicast or interfaces is not InterfaceChoice.Default self.listeners = [] # type: List[RecordUpdateListener] self.browsers = {} # type: Dict[ServiceListener, ServiceBrowser] @@ -2513,8 +2528,9 @@ def __init__( self.listener = Listener(self) if not unicast: self.engine.add_reader(self.listener, cast(socket.socket, self._listen_socket)) - for s in self._respond_sockets: - self.engine.add_reader(self.listener, s) + if self.multi_socket: + for s in self._respond_sockets: + self.engine.add_reader(self.listener, s) self.reaper = Reaper(self) self.debug = None # type: Optional[DNSOutgoing] @@ -2978,8 +2994,9 @@ def close(self) -> None: if not self.unicast: self.engine.del_reader(cast(socket.socket, self._listen_socket)) cast(socket.socket, self._listen_socket).close() - for s in self._respond_sockets: - self.engine.del_reader(s) + if self.multi_socket: + for s in self._respond_sockets: + self.engine.del_reader(s) self.engine.join() # shutdown the rest