linux-imx

/*

 * llc_c_ev.c - Connection component state transition event qualifiers

 *

 * A 'state' consists of a number of possible event matching functions,

 * the actions associated with each being executed when that event is

 * matched; a 'state machine' accepts events in a serial fashion from an

 * event queue. Each event is passed to each successive event matching

 * function until a match is made (the event matching function returns

 * success, or '0') or the list of event matching functions is exhausted.

 * If a match is made, the actions associated with the event are executed

 * and the state is changed to that event's transition state. Before some

 * events are recognized, even after a match has been made, a certain

 * number of 'event qualifier' functions must also be executed. If these

 * all execute successfully, then the event is finally executed.

 *

 * These event functions must return 0 for success, to show a matched

 * event, of 1 if the event does not match. Event qualifier functions

 * must return a 0 for success or a non-zero for failure. Each function

 * is simply responsible for verifying one single thing and returning

 * either a success or failure.

 *

 * All of followed event functions are described in 802.2 LLC Protocol

 * standard document except two functions that we added that will explain

 * in their comments, at below.

 *

 * Copyright (c) 1997 by Procom Technology, Inc.

 *       2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>

 *

 * This program can be redistributed or modified under the terms of the

 * GNU General Public License as published by the Free Software Foundation.

 * This program is distributed without any warranty or implied warranty

 * of merchantability or fitness for a particular purpose.

 *

 * See the GNU General Public License for more details.

 */

#include <linux/netdevice.h>

#include <net/llc_conn.h>

#include <net/llc_sap.h>

#include <net/sock.h>

#include <net/llc_c_ac.h>

#include <net/llc_c_ev.h>

#include <net/llc_pdu.h>

​

#if 1

#define dprintk(args...) printk(KERN_DEBUG args)

#else

#define dprintk(args...)

#endif

​

/**

 *  llc_util_ns_inside_rx_window - check if sequence number is in rx window

 *  @ns: sequence number of received pdu.

 *  @vr: sequence number which receiver expects to receive.

 *  @rw: receive window size of receiver.

 *

 *  Checks if sequence number of received PDU is in range of receive

 *  window. Returns 0 for success, 1 otherwise

 */

static u16 llc_util_ns_inside_rx_window(u8 ns, u8 vr, u8 rw)

{

    return !llc_circular_between(vr, ns,

                     (vr + rw - 1) % LLC_2_SEQ_NBR_MODULO);

}