netpycos.py 文件源码

def discover_peers(self, port=None):
        """This method can be invoked (periodically?) to broadcast message to
        discover peers, if there is a chance initial broadcast message may be
        lost (as these messages are sent over UDP).
        """
        ping_msg = {'signature': self._signature, 'name': self._name, 'version': __version__}

        def _discover(addrinfo, port, task=None):
            ping_sock = AsyncSocket(socket.socket(addrinfo.family, socket.SOCK_DGRAM))
            ping_sock.settimeout(2)
            if addrinfo.family == socket.AF_INET:
                ping_sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
            else:  # addrinfo.family == socket.AF_INET6
                ping_sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS,
                                     struct.pack('@i', 1))
                ping_sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_IF, addrinfo.ifn)
            ping_sock.bind((addrinfo.ip, 0))
            if not port:
                port = addrinfo.udp_sock.getsockname()[1]
            ping_msg['location'] = addrinfo.location
            try:
                yield ping_sock.sendto('ping:'.encode() + serialize(ping_msg),
                                       (addrinfo.broadcast, port))
            except:
                pass
            ping_sock.close()

        for addrinfo in self._addrinfos:
            SysTask(_discover, addrinfo, port)