/*
 * Copyright (c) 2007-2012 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 * 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.
 */

#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/random.h>
#include <sys/kernel_types.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/net_osdep.h>
#include <net/classq/classq.h>

#include <libkern/libkern.h>

u_int32_t classq_verbose;	/* more noise if greater than 1 */

SYSCTL_NODE(_net, OID_AUTO, classq, CTLFLAG_RW|CTLFLAG_LOCKED, 0, "classq");

SYSCTL_UINT(_net_classq, OID_AUTO, verbose, CTLFLAG_RW|CTLFLAG_LOCKED,
	&classq_verbose, 0, "Class queue verbosity level");

void
_qinit(class_queue_t *q, int type, int lim)
{
	MBUFQ_INIT(&q->mbufq);
	qlimit(q) = lim;
	qlen(q) = 0;
	qsize(q) = 0;
	qtype(q) = type;
	qstate(q) = QS_RUNNING;
}

/* add a packet at the tail of the queue */
void
_addq(class_queue_t *q, struct mbuf *m)
{
	MBUFQ_ENQUEUE(&q->mbufq, m);
	qlen(q)++;
	VERIFY(qlen(q) != 0);
	qsize(q) += m_length(m);
}

/* add one or more packets at the tail of the queue */
void
_addq_multi(class_queue_t *q, struct mbuf *m_head, struct mbuf *m_tail,
    u_int32_t cnt, u_int32_t size)
{
	MBUFQ_ENQUEUE_MULTI(&q->mbufq, m_head, m_tail);
	qlen(q) += cnt;
	qsize(q) += size;
}

/* get a packet at the head of the queue */
struct mbuf *
_getq(class_queue_t *q)
{
	struct mbuf *m;

	MBUFQ_DEQUEUE(&q->mbufq, m);
	if (m == NULL) {
		VERIFY(qlen(q) == 0);
		if (qsize(q) > 0)
			qsize(q) = 0;
		return (NULL);
	}
	VERIFY(qlen(q) > 0);
	qlen(q)--;

	/* qsize is an approximation, so adjust if necessary */
	if (((int)qsize(q) - m_length(m)) > 0)
		qsize(q) -= m_length(m);
	else if (qsize(q) != 0)
		qsize(q) = 0;

	return (m);
}

/* get a packet of a specific flow beginning from the head of the queue */
struct mbuf *
_getq_flow(class_queue_t *q, u_int32_t flow)
{
	struct mbuf *m, *m_tmp;

	MBUFQ_FOREACH_SAFE(m, &q->mbufq, m_tmp) {
		if (flow == 0 || ((m->m_flags & M_PKTHDR) &&
		    m->m_pkthdr.pkt_flowid == flow)) {
			/* remove it from the class queue */
			MBUFQ_REMOVE(&q->mbufq, m);
			MBUFQ_NEXT(m) = NULL;
			break;
		}
	}

	if (m != NULL) {
		u_int32_t l = m_length(m);

		VERIFY(qlen(q) > 0);
		qlen(q)--;

		/* qsize is an approximation, so adjust if necessary */
		if (((int)qsize(q) - l) > 0)
			qsize(q) -= l;
		else if (qsize(q) != 0)
			qsize(q) = 0;
	}

	return (m);
}

/* get all packets starting from the head of the queue */
struct mbuf *
_getq_all(class_queue_t *q)
{
	struct mbuf *m;

	m = MBUFQ_FIRST(&q->mbufq);
	MBUFQ_INIT(&q->mbufq);
	qlen(q) = 0;
	qsize(q) = 0;

	return (m);
}

/* drop a packet at the tail of the queue */
struct mbuf *
_getq_tail(class_queue_t *q)
{
	struct mq_head *head = &q->mbufq;
	struct mbuf *m = MBUFQ_LAST(head);

	if (m != NULL) {
		struct mbuf *n = MBUFQ_FIRST(head);

		while (n != NULL) {
			struct mbuf *next = MBUFQ_NEXT(n);
			if (next == m) {
				MBUFQ_NEXT(n) = NULL;
				break;
			}
			n = next;
		}
		VERIFY(n != NULL ||
		    (qlen(q) == 1 && m == MBUFQ_FIRST(head)));
		VERIFY(qlen(q) > 0);
		--qlen(q);

		/* qsize is an approximation, so adjust if necessary */
		if (((int)qsize(q) - m_length(m)) > 0)
			qsize(q) -= m_length(m);
		else if (qsize(q) != 0)
			qsize(q) = 0;

		if (qempty(q)) {
			VERIFY(MBUFQ_EMPTY(head));
			MBUFQ_INIT(head);
		} else {
			VERIFY(n != NULL);
			head->mq_last = &MBUFQ_NEXT(n);
		}
	}
	return (m);
}

/* randomly select a packet in the queue */
struct mbuf *
_getq_random(class_queue_t *q)
{
	struct mq_head *head = &q->mbufq;
	struct mbuf *m = NULL;
	unsigned int n;
	u_int32_t rnd;

	n = qlen(q);
	if (n == 0) {
		VERIFY(MBUFQ_EMPTY(head));
		if (qsize(q) > 0)
			qsize(q) = 0;
		return (NULL);
	}

	m = MBUFQ_FIRST(head);
	read_random(&rnd, sizeof (rnd));
	n = (rnd % n) + 1;

	if (n == 1) {
		if ((MBUFQ_FIRST(head) = MBUFQ_NEXT(m)) == NULL)
			(head)->mq_last = &MBUFQ_FIRST(head);
	} else {
		struct mbuf *p = NULL;

		VERIFY(n > 1);
		while (n--) {
			if (MBUFQ_NEXT(m) == NULL)
				break;
			p = m;
			m = MBUFQ_NEXT(m);
		}
		VERIFY(p != NULL && MBUFQ_NEXT(p) == m);

		if ((MBUFQ_NEXT(p) = MBUFQ_NEXT(m)) == NULL)
			(head)->mq_last = &MBUFQ_NEXT(p);
	}

	VERIFY(qlen(q) > 0);
	--qlen(q);

	/* qsize is an approximation, so adjust if necessary */
	if (((int)qsize(q) - m_length(m)) > 0)
		qsize(q) -= m_length(m);
	else if (qsize(q) != 0)
		qsize(q) = 0;

	MBUFQ_NEXT(m) = NULL;

	return (m);
}

/* remove a packet from the queue */
void
_removeq(class_queue_t *q, struct mbuf *m)
{
	struct mq_head *head = &q->mbufq;
	struct mbuf *m0, **mtail;

	m0 = MBUFQ_FIRST(head);
	if (m0 == NULL)
		return;

	if (m0 != m) {
		while (MBUFQ_NEXT(m0) != m) {
			if (m0 == NULL)
				return;
			m0 = MBUFQ_NEXT(m0);
		}
		mtail = &MBUFQ_NEXT(m0);
	} else {
		mtail = &MBUFQ_FIRST(head);
	}

	*mtail = MBUFQ_NEXT(m);
	if (*mtail == NULL)
		head->mq_last = mtail;

	VERIFY(qlen(q) > 0);
	--qlen(q);

	/* qsize is an approximation, so adjust if necessary */
	if (((int)qsize(q) - m_length(m)) > 0)
		qsize(q) -= m_length(m);
	else if (qsize(q) != 0)
		qsize(q) = 0;

	MBUFQ_NEXT(m) = NULL;
}

void
_flushq(class_queue_t *q)
{
	(void) _flushq_flow(q, 0, NULL, NULL);
}

void
_flushq_flow(class_queue_t *q, u_int32_t flow, u_int32_t *cnt, u_int32_t *len)
{
	MBUFQ_HEAD(mq_freeq) freeq;
	struct mbuf *m, *m_tmp;
	u_int32_t c = 0, l = 0;

	MBUFQ_INIT(&freeq);

	MBUFQ_FOREACH_SAFE(m, &q->mbufq, m_tmp) {
		if (flow == 0 || ((m->m_flags & M_PKTHDR) &&
		    m->m_pkthdr.pkt_flowid == flow)) {
			/* remove it from the class queue */
			MBUFQ_REMOVE(&q->mbufq, m);
			MBUFQ_NEXT(m) = NULL;

			/* and add it to the free queue */
			MBUFQ_ENQUEUE(&freeq, m);

			l += m_length(m);
			c++;
		}
	}
	VERIFY(c == 0 || !MBUFQ_EMPTY(&freeq));

	if (c > 0) {
		VERIFY(qlen(q) >= c);
		qlen(q) -= c;

		/* qsize is an approximation, so adjust if necessary */
		if (((int)qsize(q) - l) > 0)
			qsize(q) -= l;
		else if (qsize(q) != 0)
			qsize(q) = 0;
	}

	if (!MBUFQ_EMPTY(&freeq))
		m_freem_list(MBUFQ_FIRST(&freeq));

	if (cnt != NULL)
		*cnt = c;
	if (len != NULL)
		*len = l;
}