SilcBool silc_packet_get_sender(SilcPacket packet,
                                    const char **sender_ip,
                                    SilcUInt16 *sender_port);

    Returns the packet sender's IP address and port from UDP packet
    indicated by `packet'.  This can be called only from the packet
    callback to retrieve the information of the packet's sender.  Returns
    FALSE if the information is not available.