linux-imx

/*

 * net/sched/sch_red.c  Random Early Detection queue.

 *

 *      This program is free software; you can redistribute it and/or

 *      modify it under the terms of the GNU General Public License

 *      as published by the Free Software Foundation; either version

 *      2 of the License, or (at your option) any later version.

 *

 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>

 *

 * Changes:

 * J Hadi Salim 980914: computation fixes

 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.

 * J Hadi Salim 980816:  ECN support

 */

​

#include <linux/module.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/skbuff.h>

#include <net/pkt_sched.h>

#include <net/pkt_cls.h>

#include <net/inet_ecn.h>

#include <net/red.h>

​

​

/*  Parameters, settable by user:

    -----------------------------

​

    limit       - bytes (must be > qth_max + burst)

​

    Hard limit on queue length, should be chosen >qth_max

    to allow packet bursts. This parameter does not

    affect the algorithms behaviour and can be chosen

    arbitrarily high (well, less than ram size)

    Really, this limit will never be reached

    if RED works correctly.

 */

​

struct red_sched_data {

    u32         limit;      /* HARD maximal queue length */

    unsigned char       flags;

    struct timer_list   adapt_timer;

    struct Qdisc        *sch;

    struct red_parms    parms;

    struct red_vars     vars;

    struct red_stats    stats;

    struct Qdisc        *qdisc;

};

​

static inline int red_use_ecn(struct red_sched_data *q)

{

    return q->flags & TC_RED_ECN;

}

​

static inline int red_use_harddrop(struct red_sched_data *q)

{

    return q->flags & TC_RED_HARDDROP;

}

​

static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,

               struct sk_buff **to_free)

{