/*      $KAME: altq_classq.h,v 1.6 2003/01/07 07:33:38 kjc Exp $        */
/*      $DragonFly: src/sys/net/altq/altq_classq.h,v 1.2 2006/09/03 18:52:29 dillon Exp $ */

/*
 * Copyright (c) 1991-1997 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the Network Research
 *      Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * class queue definitions extracted from rm_class.h.
 */
#ifndef _ALTQ_ALTQ_CLASSQ_H_
#define _ALTQ_ALTQ_CLASSQ_H_

#include <net/altq/if_classq.h>

/*
 * Packet Queue types: RED or DROPHEAD.
 */
#define Q_DROPHEAD      0x00
#define Q_RED           0x01
#define Q_RIO           0x02
#define Q_DROPTAIL      0x03

#ifdef _KERNEL

/*
 * Packet Queue structures and macros to manipulate them.
 */
struct _class_queue_ {
        struct if_classq que_;
        int     qlen_;          /* Queue length (in number of packets) */
        int     qlim_;          /* Queue limit (in number of packets*) */
        int     qtype_;         /* Queue type */
};

typedef struct _class_queue_    class_queue_t;

#define qtype(q)        (q)->qtype_             /* Get queue type */
#define qlimit(q)       (q)->qlim_              /* Max packets to be queued */
#define qlen(q)         (q)->qlen_              /* Current queue length. */
#define qtail(q)        classq_tail(&(q)->que_) /* Tail of the queue */
#define qhead(q)        classq_head(&(q)->que_)

#define qempty(q)       ((q)->qlen_ == 0)       /* Is the queue empty?? */
#define q_is_red(q)     ((q)->qtype_ == Q_RED)  /* Is the queue a red queue */
#define q_is_rio(q)     ((q)->qtype_ == Q_RIO)  /* Is the queue a rio queue */
#define q_is_red_or_rio(q)      ((q)->qtype_ == Q_RED || (q)->qtype_ == Q_RIO)

static __inline void
_addq(class_queue_t *q, struct mbuf *m)
{
        classq_add(&q->que_, m);
        qlen(q)++;
}

static __inline struct mbuf *
_getq(class_queue_t *q)
{
        struct mbuf *m;

        m = classq_get(&q->que_);
        if (m != NULL)
                qlen(q)--;
        return (m);
}

/* drop a packet at the tail of the queue */
static __inline struct mbuf *
_getq_tail(class_queue_t *q)
{
        struct mbuf *m, *m0, *prev;

        if ((m = m0 = qtail(q)) == NULL)
                return NULL;
        do {
                prev = m0;
                m0 = m0->m_nextpkt;
        } while (m0 != m);
        prev->m_nextpkt = m->m_nextpkt;
        if (prev == m)
                qtail(q) = NULL;
        else
                qtail(q) = prev;
        qlen(q)--;
        m->m_nextpkt = NULL;
        return (m);
}

/* randomly select a packet in the queue */
static __inline struct mbuf *
_getq_random(class_queue_t *q)
{
        struct mbuf *m;
        int i, n;

        if ((m = qtail(q)) == NULL)
                return NULL;
        if (m->m_nextpkt == m)
                qtail(q) = NULL;
        else {
                struct mbuf *prev = NULL;

                n = krandom() % qlen(q) + 1;
                for (i = 0; i < n; i++) {
                        prev = m;
                        m = m->m_nextpkt;
                }
                prev->m_nextpkt = m->m_nextpkt;
                if (m == qtail(q))
                        qtail(q) = prev;
        }
        qlen(q)--;
        m->m_nextpkt = NULL;
        return (m);
}

static __inline void
_removeq(class_queue_t *q, struct mbuf *m)
{
        struct mbuf *m0, *prev;

        m0 = qtail(q);
        do {
                prev = m0;
                m0 = m0->m_nextpkt;
        } while (m0 != m);
        prev->m_nextpkt = m->m_nextpkt;
        if (prev == m)
                qtail(q) = NULL;
        else if (qtail(q) == m)
                qtail(q) = prev;
        qlen(q)--;
}

static __inline void
_flushq(class_queue_t *q)
{
        struct mbuf *m;

        while ((m = _getq(q)) != NULL)
                m_freem(m);
}

#endif /* _KERNEL */

#endif /* _ALTQ_ALTQ_CLASSQ_H_ */