* Copyright (c) 1991-1997 Regents of the University of California.

/* $NetBSD: altq_classq.h,v 1.12 2025/01/22 22:41:38 joe Exp $ */
/* $KAME: altq_classq.h,v 1.6 2003/01/07 07:33:38 kjc 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_

#ifdef __cplusplus
extern "C" {
#endif

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

#ifdef _KERNEL

#include <sys/cprng.h>

/*
* Packet Queue structures and macros to manipulate them.
*/
struct _class_queue_ {
struct mbuf *tail_; /* Tail of packet queue */
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) (q)->tail_ /* Tail of the queue */
#define qhead(q) ((q)->tail_ ? (q)->tail_->m_nextpkt : NULL)

#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)

#if !defined(__GNUC__) || defined(ALTQ_DEBUG)

extern void _addq(class_queue_t *, struct mbuf *);
extern struct mbuf *_getq(class_queue_t *);
extern struct mbuf *_getq_tail(class_queue_t *);
extern struct mbuf *_getq_random(class_queue_t *);
extern void _removeq(class_queue_t *, struct mbuf *);
extern void _flushq(class_queue_t *);

#else /* __GNUC__ && !ALTQ_DEBUG */
/*
* inlined versions
*/
static __inline void
_addq(class_queue_t *q, struct mbuf *m)
{
struct mbuf *m0;

if ((m0 = qtail(q)) != NULL)
m->m_nextpkt = m0->m_nextpkt;
else
m0 = m;
m0->m_nextpkt = m;
qtail(q) = m;
qlen(q)++;
}

static __inline struct mbuf *
_getq(class_queue_t *q)
{
struct mbuf *m, *m0;

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

/* 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 = cprng_fast32() % 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 /* __GNUC__ && !ALTQ_DEBUG */

#endif /* _KERNEL */

#ifdef __cplusplus
}
#endif

#endif /* _ALTQ_ALTQ_CLASSQ_H_ */