taglinefilesource code
sock_wspace249net/inet/packet.csock_wspace,
sock_wspace374net/inet/raw.csock_wspace,
sock_wspace217net/inet/sock.hextern unsigned long    sock_wspace(struct sock *sk);
sock_wspace3399net/inet/tcp.csock_wspace,
sock_wspace620net/inet/udp.csock_wspace,