def getaddrinfo(space, w_host, w_port,
                family=rsocket.AF_UNSPEC, socktype=0, proto=0, flags=0):
    """getaddrinfo(host, port [, family, socktype, proto, flags])
        -> list of (family, socktype, proto, canonname, sockaddr)

    Resolve host and port into addrinfo struct.
    """
    # host can be None, string or unicode
    if space.is_w(w_host, space.w_None):
        host = None
    elif space.is_true(space.isinstance(w_host, space.w_str)):
        host = space.str_w(w_host)
    elif space.is_true(space.isinstance(w_host, space.w_unicode)):
        w_shost = space.call_method(w_host, "encode", space.wrap("idna"))
        host = space.str_w(w_shost)
    else:
        raise OperationError(space.w_TypeError,
                             space.wrap(
            "getaddrinfo() argument 1 must be string or None"))

    # port can be None, int or string
    if space.is_w(w_port, space.w_None):
        port = None
    elif space.is_true(space.isinstance(w_port, space.w_int)):
        port = str(space.int_w(w_port))
    elif space.is_true(space.isinstance(w_port, space.w_str)):
        port = space.str_w(w_port)
    else:
        raise OperationError(space.w_TypeError,
                             space.wrap("Int or String expected"))
    try:
        lst = rsocket.getaddrinfo(host, port, family, socktype,
                                  proto, flags)
    except SocketError, e:
        raise converted_error(space, e)

def _ssl_seterror(space, ss, ret):
    assert ret <= 0

    if ss is None:
        errval = libssl_ERR_peek_last_error()
        errstr = rffi.charp2str(libssl_ERR_error_string(errval, None))
        return ssl_error(space, errstr, errval)
    elif ss.ssl:
        err = libssl_SSL_get_error(ss.ssl, ret)
    else:
        err = SSL_ERROR_SSL
    errstr = ""
    errval = 0

    if err == SSL_ERROR_ZERO_RETURN:
        errstr = "TLS/SSL connection has been closed"
        errval = PY_SSL_ERROR_ZERO_RETURN
    elif err == SSL_ERROR_WANT_READ:
        errstr = "The operation did not complete (read)"
        errval = PY_SSL_ERROR_WANT_READ
    elif err == SSL_ERROR_WANT_WRITE:
        errstr = "The operation did not complete (write)"
        errval = PY_SSL_ERROR_WANT_WRITE
    elif err == SSL_ERROR_WANT_X509_LOOKUP:
        errstr = "The operation did not complete (X509 lookup)"
        errval = PY_SSL_ERROR_WANT_X509_LOOKUP
    elif err == SSL_ERROR_WANT_CONNECT:
        errstr = "The operation did not complete (connect)"
        errval = PY_SSL_ERROR_WANT_CONNECT
    elif err == SSL_ERROR_SYSCALL:
        e = libssl_ERR_get_error()
        if e == 0:
            if ret == 0 or space.is_w(ss.w_socket, space.w_None):
                errstr = "EOF occurred in violation of protocol"
                errval = PY_SSL_ERROR_EOF
            elif ret == -1:
                # the underlying BIO reported an I/0 error
                error = rsocket.last_error()
                return interp_socket.converted_error(space, error)
            else:
                errstr = "Some I/O error occurred"
                errval = PY_SSL_ERROR_SYSCALL
        else:
            errstr = rffi.charp2str(libssl_ERR_error_string(e, None))
            errval = PY_SSL_ERROR_SYSCALL
    elif err == SSL_ERROR_SSL:
        e = libssl_ERR_get_error()
        errval = PY_SSL_ERROR_SSL
        if e != 0:
            errstr = rffi.charp2str(libssl_ERR_error_string(e, None))
        else:
            errstr = "A failure in the SSL library occurred"
    else:
        errstr = "Invalid error code"
        errval = PY_SSL_ERROR_INVALID_ERROR_CODE

    return ssl_error(space, errstr, errval)

def getnameinfo(space, w_sockaddr, flags):
    """getnameinfo(sockaddr, flags) --> (host, port)

    Get host and port for a sockaddr."""
    try:
        addr = ipaddr_from_object(space, w_sockaddr)
        host, servport = rsocket.getnameinfo(addr, flags)
    except SocketError as e:
        raise converted_error(space, e)
    return space.newtuple([space.wrap(host), space.wrap(servport)])

def gethostbyaddr(space, host):
    """gethostbyaddr(host) -> (name, aliaslist, addresslist)

    Return the true host name, a list of aliases, and a list of IP addresses,
    for a host.  The host argument is a string giving a host name or IP number.
    """
    try:
        res = rsocket.gethostbyaddr(host)
    except SocketError, e:
        raise converted_error(space, e)

def socketpair(space, family=rsocket.socketpair_default_family, type=rsocket.SOCK_STREAM, proto=0):
    """socketpair([family[, type[, proto]]]) -> (socket object, socket object)

    Create a pair of socket objects from the sockets returned by the platform
    socketpair() function.
    The arguments are the same as for socket() except the default family is
    AF_UNIX if defined on the platform; otherwise, the default is AF_INET.
    """
    try:
        sock1, sock2 = rsocket.socketpair(family, type, proto, W_RSocket)
    except SocketError, e:
        raise converted_error(space, e)

def inet_ntop(space, family, packed):
    """inet_ntop(family, packed_ip) -> string formatted IP address

    Convert a packed IP address of the given family to string format.
    """
    try:
        ip = rsocket.inet_ntop(family, packed)
    except SocketError as e:
        raise converted_error(space, e)
    except ValueError:
        raise oefmt(space.w_ValueError,
                    "invalid length of packed IP address string")
    return space.wrap(ip)

def gethostname(space):
    """gethostname() -> string

    Return the current host name.
    """
    try:
        GIL = space.threadlocals.getGIL()
        if GIL is not None: GIL.release()
        try:
            res = rsocket.gethostname()
        finally:
            if GIL is not None: GIL.acquire(True)
    except SocketError, e:
        raise converted_error(space, e)

def getprotobyname(space, name):
    """getprotobyname(name) -> integer

    Return the protocol number for the named protocol.  (Rarely used.)
    """
    try:
        GIL = space.threadlocals.getGIL()
        if GIL is not None: GIL.release()
        try:
            proto = rsocket.getprotobyname(name)
        finally:
            if GIL is not None: GIL.acquire(True)
    except SocketError, e:
        raise converted_error(space, e)

def getnameinfo(space, w_sockaddr, flags):
    """getnameinfo(sockaddr, flags) --> (host, port)

    Get host and port for a sockaddr."""
    try:
        GIL = space.threadlocals.getGIL()
        if GIL is not None: GIL.release()
        try:
            addr = rsocket.ipaddr_from_object(space, w_sockaddr)
            host, servport = rsocket.getnameinfo(addr, flags)
        finally:
            if GIL is not None: GIL.acquire(True)
            
    except SocketError, e:
        raise converted_error(space, e)

def gethostbyname(space, hostname):
    """gethostbyname(host) -> address

    Return the IP address (a string of the form '255.255.255.255') for a host.
    """
    try:
        GIL = space.threadlocals.getGIL()
        if GIL is not None: GIL.release()
        try:
            addr = rsocket.gethostbyname(hostname)
        finally:
            if GIL is not None: GIL.acquire(True)
        ip = addr.get_host()
    except SocketError, e:
        raise converted_error(space, e)

def getservbyport(space, port, w_proto=None):
    """getservbyport(port[, protocolname]) -> string

    Return the service name from a port number and protocol name.
    The optional protocol name, if given, should be 'tcp' or 'udp',
    otherwise any protocol will match.
    """
    if space.is_w(w_proto, space.w_None):
        proto = None
    else:
        proto = space.str_w(w_proto)
    try:
        service = rsocket.getservbyport(port, proto)
    except SocketError, e:
        raise converted_error(space, e)

def gethostbyaddr(space, host):
    """gethostbyaddr(host) -> (name, aliaslist, addresslist)

    Return the true host name, a list of aliases, and a list of IP addresses,
    for a host.  The host argument is a string giving a host name or IP number.
    """
    try:
        GIL = space.threadlocals.getGIL()
        if GIL is not None: GIL.release()
        try:
            res = rsocket.gethostbyaddr(host)
        finally:
            if GIL is not None: GIL.acquire(True)
    except SocketError, e:
        raise converted_error(space, e)

def getnameinfo(space, w_sockaddr, flags):
    """getnameinfo(sockaddr, flags) --> (host, port)

    Get host and port for a sockaddr."""
    try:
        host = space.str_w((space.getitem(w_sockaddr, space.wrap(0))))
        port = str(space.int_w(space.getitem(w_sockaddr, space.wrap(1))))
        lst = rsocket.getaddrinfo(host, port, rsocket.AF_UNSPEC,
                                  rsocket.SOCK_DGRAM, 0,
                                  rsocket.AI_NUMERICHOST)
        if len(lst) > 1:
            raise OperationError(
                get_error(space, 'error'),
                space.wrap("sockaddr resolved to multiple addresses"))
        addr = lst[0][4]
        fill_from_object(addr, space, w_sockaddr)
        host, servport = rsocket.getnameinfo(addr, flags)
    except SocketError, e:
        raise converted_error(space, e)

def getservbyport(space, port, w_proto):
    """getservbyport(port[, protocolname]) -> string

    Return the service name from a port number and protocol name.
    The optional protocol name, if given, should be 'tcp' or 'udp',
    otherwise any protocol will match.
    """
    if space.is_w(w_proto, space.w_None):
        proto = None
    else:
        proto = space.str_w(w_proto)

    if port < 0 or port > 0xffff:
        raise oefmt(space.w_ValueError, "getservbyport: port must be 0-65535.")

    try:
        service = rsocket.getservbyport(port, proto)
    except SocketError as e:
        raise converted_error(space, e)
    return space.wrap(service)

def getservbyname(space, name, w_proto=None):
    """getservbyname(servicename[, protocolname]) -> integer

    Return a port number from a service name and protocol name.
    The optional protocol name, if given, should be 'tcp' or 'udp',
    otherwise any protocol will match.
    """
    if space.is_w(w_proto, space.w_None):
        proto = None
    else:
        proto = space.str_w(w_proto)
    try:
        GIL = space.threadlocals.getGIL()
        if GIL is not None: GIL.release()
        try:
            port = rsocket.getservbyname(name, proto)
        finally:
            if GIL is not None: GIL.acquire(True)
    except SocketError, e:
        raise converted_error(space, e)

def getaddrinfo(space, w_host, w_port,
                family=rsocket.AF_UNSPEC, socktype=0, proto=0, flags=0):
    """getaddrinfo(host, port [, family, socktype, proto, flags])
        -> list of (family, socktype, proto, canonname, sockaddr)

    Resolve host and port into addrinfo struct.
    """
    # host can be None, string or unicode
    if space.is_w(w_host, space.w_None):
        host = None
    elif space.isinstance_w(w_host, space.w_str):
        host = space.bytes_w(w_host)
    elif space.isinstance_w(w_host, space.w_unicode):
        w_shost = space.call_method(w_host, "encode", space.wrap("idna"))
        host = space.bytes_w(w_shost)
    else:
        raise oefmt(space.w_TypeError,
                    "getaddrinfo() argument 1 must be string or None")

    # port can be None, int or string
    if space.is_w(w_port, space.w_None):
        port = None
    elif space.isinstance_w(w_port, space.w_int) or space.isinstance_w(w_port, space.w_long):
        port = str(space.int_w(w_port))
    elif space.isinstance_w(w_port, space.w_str):
        port = space.bytes_w(w_port)
    else:
        raise oefmt(space.w_TypeError,
                    "getaddrinfo() argument 2 must be integer or string")
    try:
        lst = rsocket.getaddrinfo(host, port, family, socktype,
                                  proto, flags)
    except SocketError as e:
        raise converted_error(space, e)
    lst1 = [space.newtuple([space.wrap(family),
                            space.wrap(socktype),
                            space.wrap(protocol),
                            space.wrap(canonname),
                            addr_as_object(addr, INVALID_SOCKET, space)]) # -1 as per cpython
            for (family, socktype, protocol, canonname, addr) in lst]
    return space.newlist(lst1)