地址簇(address family) socket.AF_UNIX # (UNIX Domain Sockets) socket.AF_INET # ipv4 socket.AF_INET6 # ipv6
套接字类型(socket type) socket.SOCK_STREAM # tcp socket.SOCK_DGRAM # udp socket.SOCK_RAW socket.SOCK_RDM socket.SOCK_SEQPACKET