NetBSD/sys/altq/altq_priq.c

/*	$NetBSD: altq_priq.c,v 1.20 2008/06/18 09:06:27 yamt Exp $	*/
/*	$KAME: altq_priq.c,v 1.13 2005/04/13 03:44:25 suz Exp $	*/
/*
 * Copyright (C) 2000-2003
 *	Sony Computer Science Laboratories Inc.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY SONY CSL 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 SONY CSL 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.
 */

/*
 * priority queue
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: altq_priq.c,v 1.20 2008/06/18 09:06:27 yamt Exp $");

#ifdef _KERNEL_OPT
#include "opt_altq.h"
#include "opt_inet.h"
#include "pf.h"
#endif

#ifdef ALTQ_PRIQ  /* priq is enabled by ALTQ_PRIQ option in opt_altq.h */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/queue.h>
#include <sys/kauth.h>

#include <net/if.h>
#include <netinet/in.h>

#if NPF > 0
#include <net/pfvar.h>
#endif
#include <altq/altq.h>
#include <altq/altq_conf.h>
#include <altq/altq_priq.h>

/*
 * function prototypes
 */
#ifdef ALTQ3_COMPAT
static struct priq_if *priq_attach(struct ifaltq *, u_int);
static int priq_detach(struct priq_if *);
#endif
static int priq_clear_interface(struct priq_if *);
static int priq_request(struct ifaltq *, int, void *);
static void priq_purge(struct priq_if *);
static struct priq_class *priq_class_create(struct priq_if *, int, int, int,
    int);
static int priq_class_destroy(struct priq_class *);
static int priq_enqueue(struct ifaltq *, struct mbuf *, struct altq_pktattr *);
static struct mbuf *priq_dequeue(struct ifaltq *, int);

static int priq_addq(struct priq_class *, struct mbuf *);
static struct mbuf *priq_getq(struct priq_class *);
static struct mbuf *priq_pollq(struct priq_class *);
static void priq_purgeq(struct priq_class *);

#ifdef ALTQ3_COMPAT
static int priqcmd_if_attach(struct priq_interface *);
static int priqcmd_if_detach(struct priq_interface *);
static int priqcmd_add_class(struct priq_add_class *);
static int priqcmd_delete_class(struct priq_delete_class *);
static int priqcmd_modify_class(struct priq_modify_class *);
static int priqcmd_add_filter(struct priq_add_filter *);
static int priqcmd_delete_filter(struct priq_delete_filter *);
static int priqcmd_class_stats(struct priq_class_stats *);
#endif /* ALTQ3_COMPAT */

static void get_class_stats(struct priq_classstats *, struct priq_class *);
static struct priq_class *clh_to_clp(struct priq_if *, u_int32_t);

#ifdef ALTQ3_COMPAT
altqdev_decl(priq);

/* pif_list keeps all priq_if's allocated. */
static struct priq_if *pif_list = NULL;
#endif /* ALTQ3_COMPAT */

#if NPF > 0
int
priq_pfattach(struct pf_altq *a)
{
	struct ifnet *ifp;
	int s, error;

	if ((ifp = ifunit(a->ifname)) == NULL || a->altq_disc == NULL)
		return (EINVAL);
	s = splnet();
	error = altq_attach(&ifp->if_snd, ALTQT_PRIQ, a->altq_disc,
	    priq_enqueue, priq_dequeue, priq_request, NULL, NULL);
	splx(s);
	return (error);
}

int
priq_add_altq(struct pf_altq *a)
{
	struct priq_if	*pif;
	struct ifnet	*ifp;

	if ((ifp = ifunit(a->ifname)) == NULL)
		return (EINVAL);
	if (!ALTQ_IS_READY(&ifp->if_snd))
		return (ENODEV);

	pif = malloc(sizeof(struct priq_if), M_DEVBUF, M_WAITOK|M_ZERO);
	if (pif == NULL)
		return (ENOMEM);
	pif->pif_bandwidth = a->ifbandwidth;
	pif->pif_maxpri = -1;
	pif->pif_ifq = &ifp->if_snd;

	/* keep the state in pf_altq */
	a->altq_disc = pif;

	return (0);
}

int
priq_remove_altq(struct pf_altq *a)
{
	struct priq_if *pif;

	if ((pif = a->altq_disc) == NULL)
		return (EINVAL);
	a->altq_disc = NULL;

	(void)priq_clear_interface(pif);

	free(pif, M_DEVBUF);
	return (0);
}

int
priq_add_queue(struct pf_altq *a)
{
	struct priq_if *pif;
	struct priq_class *cl;

	if ((pif = a->altq_disc) == NULL)
		return (EINVAL);

	/* check parameters */
	if (a->priority >= PRIQ_MAXPRI)
		return (EINVAL);
	if (a->qid == 0)
		return (EINVAL);
	if (pif->pif_classes[a->priority] != NULL)
		return (EBUSY);
	if (clh_to_clp(pif, a->qid) != NULL)
		return (EBUSY);

	cl = priq_class_create(pif, a->priority, a->qlimit,
	    a->pq_u.priq_opts.flags, a->qid);
	if (cl == NULL)
		return (ENOMEM);

	return (0);
}

int
priq_remove_queue(struct pf_altq *a)
{
	struct priq_if *pif;
	struct priq_class *cl;

	if ((pif = a->altq_disc) == NULL)
		return (EINVAL);

	if ((cl = clh_to_clp(pif, a->qid)) == NULL)
		return (EINVAL);

	return (priq_class_destroy(cl));
}

int
priq_getqstats(struct pf_altq *a, void *ubuf, int *nbytes)
{
	struct priq_if *pif;
	struct priq_class *cl;
	struct priq_classstats stats;
	int error = 0;

	if ((pif = altq_lookup(a->ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	if ((cl = clh_to_clp(pif, a->qid)) == NULL)
		return (EINVAL);

	if (*nbytes < sizeof(stats))
		return (EINVAL);

	get_class_stats(&stats, cl);

	if ((error = copyout((void *)&stats, ubuf, sizeof(stats))) != 0)
		return (error);
	*nbytes = sizeof(stats);
	return (0);
}
#endif /* NPF > 0 */

/*
 * bring the interface back to the initial state by discarding
 * all the filters and classes.
 */
static int
priq_clear_interface(struct priq_if *pif)
{
	struct priq_class	*cl;
	int pri;

#ifdef ALTQ3_CLFIER_COMPAT
	/* free the filters for this interface */
	acc_discard_filters(&pif->pif_classifier, NULL, 1);
#endif

	/* clear out the classes */
	for (pri = 0; pri <= pif->pif_maxpri; pri++)
		if ((cl = pif->pif_classes[pri]) != NULL)
			priq_class_destroy(cl);

	return (0);
}

static int
priq_request(struct ifaltq *ifq, int req, void *arg)
{
	struct priq_if	*pif = (struct priq_if *)ifq->altq_disc;

	switch (req) {
	case ALTRQ_PURGE:
		priq_purge(pif);
		break;
	}
	return (0);
}

/* discard all the queued packets on the interface */
static void
priq_purge(struct priq_if *pif)
{
	struct priq_class *cl;
	int pri;

	for (pri = 0; pri <= pif->pif_maxpri; pri++) {
		if ((cl = pif->pif_classes[pri]) != NULL && !qempty(cl->cl_q))
			priq_purgeq(cl);
	}
	if (ALTQ_IS_ENABLED(pif->pif_ifq))
		pif->pif_ifq->ifq_len = 0;
}

static struct priq_class *
priq_class_create(struct priq_if *pif, int pri, int qlimit, int flags, int qid)
{
	struct priq_class *cl;
	int s;

#ifndef ALTQ_RED
	if (flags & PRCF_RED) {
#ifdef ALTQ_DEBUG
		printf("priq_class_create: RED not configured for PRIQ!\n");
#endif
		return (NULL);
	}
#endif

	if ((cl = pif->pif_classes[pri]) != NULL) {
		/* modify the class instead of creating a new one */
		s = splnet();
		if (!qempty(cl->cl_q))
			priq_purgeq(cl);
		splx(s);
#ifdef ALTQ_RIO
		if (q_is_rio(cl->cl_q))
			rio_destroy((rio_t *)cl->cl_red);
#endif
#ifdef ALTQ_RED
		if (q_is_red(cl->cl_q))
			red_destroy(cl->cl_red);
#endif
	} else {
		cl = malloc(sizeof(struct priq_class), M_DEVBUF,
		    M_WAITOK|M_ZERO);
		if (cl == NULL)
			return (NULL);

		cl->cl_q = malloc(sizeof(class_queue_t), M_DEVBUF,
		    M_WAITOK|M_ZERO);
		if (cl->cl_q == NULL)
			goto err_ret;
	}

	pif->pif_classes[pri] = cl;
	if (flags & PRCF_DEFAULTCLASS)
		pif->pif_default = cl;
	if (qlimit == 0)
		qlimit = 50;  /* use default */
	qlimit(cl->cl_q) = qlimit;
	qtype(cl->cl_q) = Q_DROPTAIL;
	qlen(cl->cl_q) = 0;
	cl->cl_flags = flags;
	cl->cl_pri = pri;
	if (pri > pif->pif_maxpri)
		pif->pif_maxpri = pri;
	cl->cl_pif = pif;
	cl->cl_handle = qid;

#ifdef ALTQ_RED
	if (flags & (PRCF_RED|PRCF_RIO)) {
		int red_flags, red_pkttime;

		red_flags = 0;
		if (flags & PRCF_ECN)
			red_flags |= REDF_ECN;
#ifdef ALTQ_RIO
		if (flags & PRCF_CLEARDSCP)
			red_flags |= RIOF_CLEARDSCP;
#endif
		if (pif->pif_bandwidth < 8)
			red_pkttime = 1000 * 1000 * 1000; /* 1 sec */
		else
			red_pkttime = (int64_t)pif->pif_ifq->altq_ifp->if_mtu
			  * 1000 * 1000 * 1000 / (pif->pif_bandwidth / 8);
#ifdef ALTQ_RIO
		if (flags & PRCF_RIO) {
			cl->cl_red = (red_t *)rio_alloc(0, NULL,
						red_flags, red_pkttime);
			if (cl->cl_red != NULL)
				qtype(cl->cl_q) = Q_RIO;
		} else
#endif
		if (flags & PRCF_RED) {
			cl->cl_red = red_alloc(0, 0,
			    qlimit(cl->cl_q) * 10/100,
			    qlimit(cl->cl_q) * 30/100,
			    red_flags, red_pkttime);
			if (cl->cl_red != NULL)
				qtype(cl->cl_q) = Q_RED;
		}
	}
#endif /* ALTQ_RED */

	return (cl);

 err_ret:
	if (cl->cl_red != NULL) {
#ifdef ALTQ_RIO
		if (q_is_rio(cl->cl_q))
			rio_destroy((rio_t *)cl->cl_red);
#endif
#ifdef ALTQ_RED
		if (q_is_red(cl->cl_q))
			red_destroy(cl->cl_red);
#endif
	}
	if (cl->cl_q != NULL)
		free(cl->cl_q, M_DEVBUF);
	free(cl, M_DEVBUF);
	return (NULL);
}

static int
priq_class_destroy(struct priq_class *cl)
{
	struct priq_if *pif;
	int s, pri;

	s = splnet();

#ifdef ALTQ3_CLFIER_COMPAT
	/* delete filters referencing to this class */
	acc_discard_filters(&cl->cl_pif->pif_classifier, cl, 0);
#endif

	if (!qempty(cl->cl_q))
		priq_purgeq(cl);

	pif = cl->cl_pif;
	pif->pif_classes[cl->cl_pri] = NULL;
	if (pif->pif_maxpri == cl->cl_pri) {
		for (pri = cl->cl_pri; pri >= 0; pri--)
			if (pif->pif_classes[pri] != NULL) {
				pif->pif_maxpri = pri;
				break;
			}
		if (pri < 0)
			pif->pif_maxpri = -1;
	}
	splx(s);

	if (cl->cl_red != NULL) {
#ifdef ALTQ_RIO
		if (q_is_rio(cl->cl_q))
			rio_destroy((rio_t *)cl->cl_red);
#endif
#ifdef ALTQ_RED
		if (q_is_red(cl->cl_q))
			red_destroy(cl->cl_red);
#endif
	}
	free(cl->cl_q, M_DEVBUF);
	free(cl, M_DEVBUF);
	return (0);
}

/*
 * priq_enqueue is an enqueue function to be registered to
 * (*altq_enqueue) in struct ifaltq.
 */
static int
priq_enqueue(struct ifaltq *ifq, struct mbuf *m, struct altq_pktattr *pktattr)
{
	struct priq_if	*pif = (struct priq_if *)ifq->altq_disc;
	struct priq_class *cl;
	struct m_tag *t;
	int len;

	/* grab class set by classifier */
	if ((m->m_flags & M_PKTHDR) == 0) {
		/* should not happen */
		printf("altq: packet for %s does not have pkthdr\n",
		    ifq->altq_ifp->if_xname);
		m_freem(m);
		return (ENOBUFS);
	}
	cl = NULL;
	if ((t = m_tag_find(m, PACKET_TAG_ALTQ_QID, NULL)) != NULL)
		cl = clh_to_clp(pif, ((struct altq_tag *)(t+1))->qid);
#ifdef ALTQ3_COMPAT
	else if ((ifq->altq_flags & ALTQF_CLASSIFY) && pktattr != NULL)
		cl = pktattr->pattr_class;
#endif
	if (cl == NULL) {
		cl = pif->pif_default;
		if (cl == NULL) {
			m_freem(m);
			return (ENOBUFS);
		}
	}
#ifdef ALTQ3_COMPAT
	if (pktattr != NULL)
		cl->cl_pktattr = pktattr;  /* save proto hdr used by ECN */
	else
#endif
		cl->cl_pktattr = NULL;
	len = m_pktlen(m);
	if (priq_addq(cl, m) != 0) {
		/* drop occurred.  mbuf was freed in priq_addq. */
		PKTCNTR_ADD(&cl->cl_dropcnt, len);
		return (ENOBUFS);
	}
	IFQ_INC_LEN(ifq);

	/* successfully queued. */
	return (0);
}

/*
 * priq_dequeue is a dequeue function to be registered to
 * (*altq_dequeue) in struct ifaltq.
 *
 * note: ALTDQ_POLL returns the next packet without removing the packet
 *	from the queue.  ALTDQ_REMOVE is a normal dequeue operation.
 *	ALTDQ_REMOVE must return the same packet if called immediately
 *	after ALTDQ_POLL.
 */
static struct mbuf *
priq_dequeue(struct ifaltq *ifq, int op)
{
	struct priq_if	*pif = (struct priq_if *)ifq->altq_disc;
	struct priq_class *cl;
	struct mbuf *m;
	int pri;

	if (IFQ_IS_EMPTY(ifq))
		/* no packet in the queue */
		return (NULL);

	for (pri = pif->pif_maxpri;  pri >= 0; pri--) {
		if ((cl = pif->pif_classes[pri]) != NULL &&
		    !qempty(cl->cl_q)) {
			if (op == ALTDQ_POLL)
				return (priq_pollq(cl));

			m = priq_getq(cl);
			if (m != NULL) {
				IFQ_DEC_LEN(ifq);
				if (qempty(cl->cl_q))
					cl->cl_period++;
				PKTCNTR_ADD(&cl->cl_xmitcnt, m_pktlen(m));
			}
			return (m);
		}
	}
	return (NULL);
}

static int
priq_addq(struct priq_class *cl, struct mbuf *m)
{

#ifdef ALTQ_RIO
	if (q_is_rio(cl->cl_q))
		return rio_addq((rio_t *)cl->cl_red, cl->cl_q, m,
				cl->cl_pktattr);
#endif
#ifdef ALTQ_RED
	if (q_is_red(cl->cl_q))
		return red_addq(cl->cl_red, cl->cl_q, m, cl->cl_pktattr);
#endif
	if (qlen(cl->cl_q) >= qlimit(cl->cl_q)) {
		m_freem(m);
		return (-1);
	}

	if (cl->cl_flags & PRCF_CLEARDSCP)
		write_dsfield(m, cl->cl_pktattr, 0);

	_addq(cl->cl_q, m);

	return (0);
}

static struct mbuf *
priq_getq(struct priq_class *cl)
{
#ifdef ALTQ_RIO
	if (q_is_rio(cl->cl_q))
		return rio_getq((rio_t *)cl->cl_red, cl->cl_q);
#endif
#ifdef ALTQ_RED
	if (q_is_red(cl->cl_q))
		return red_getq(cl->cl_red, cl->cl_q);
#endif
	return _getq(cl->cl_q);
}

static struct mbuf *
priq_pollq(cl)
	struct priq_class *cl;
{
	return qhead(cl->cl_q);
}

static void
priq_purgeq(struct priq_class *cl)
{
	struct mbuf *m;

	if (qempty(cl->cl_q))
		return;

	while ((m = _getq(cl->cl_q)) != NULL) {
		PKTCNTR_ADD(&cl->cl_dropcnt, m_pktlen(m));
		m_freem(m);
	}
	ASSERT(qlen(cl->cl_q) == 0);
}

static void
get_class_stats(struct priq_classstats *sp, struct priq_class *cl)
{
	sp->class_handle = cl->cl_handle;
	sp->qlength = qlen(cl->cl_q);
	sp->qlimit = qlimit(cl->cl_q);
	sp->period = cl->cl_period;
	sp->xmitcnt = cl->cl_xmitcnt;
	sp->dropcnt = cl->cl_dropcnt;

	sp->qtype = qtype(cl->cl_q);
#ifdef ALTQ_RED
	if (q_is_red(cl->cl_q))
		red_getstats(cl->cl_red, &sp->red[0]);
#endif
#ifdef ALTQ_RIO
	if (q_is_rio(cl->cl_q))
		rio_getstats((rio_t *)cl->cl_red, &sp->red[0]);
#endif

}

/* convert a class handle to the corresponding class pointer */
static struct priq_class *
clh_to_clp(struct priq_if *pif, u_int32_t chandle)
{
	struct priq_class *cl;
	int idx;

	if (chandle == 0)
		return (NULL);

	for (idx = pif->pif_maxpri; idx >= 0; idx--)
		if ((cl = pif->pif_classes[idx]) != NULL &&
		    cl->cl_handle == chandle)
			return (cl);

	return (NULL);
}


#ifdef ALTQ3_COMPAT

static struct priq_if *
priq_attach(struct ifaltq *ifq, u_int bandwidth)
{
	struct priq_if *pif;

	pif = malloc(sizeof(struct priq_if), M_DEVBUF, M_WAITOK|M_ZERO);
	if (pif == NULL)
		return (NULL);
	pif->pif_bandwidth = bandwidth;
	pif->pif_maxpri = -1;
	pif->pif_ifq = ifq;

	/* add this state to the priq list */
	pif->pif_next = pif_list;
	pif_list = pif;

	return (pif);
}

static int
priq_detach(struct priq_if *pif)
{
	(void)priq_clear_interface(pif);

	/* remove this interface from the pif list */
	if (pif_list == pif)
		pif_list = pif->pif_next;
	else {
		struct priq_if *p;

		for (p = pif_list; p != NULL; p = p->pif_next)
			if (p->pif_next == pif) {
				p->pif_next = pif->pif_next;
				break;
			}
		ASSERT(p != NULL);
	}

	free(pif, M_DEVBUF);
	return (0);
}

/*
 * priq device interface
 */
int
priqopen(dev_t dev, int flag, int fmt,
    struct lwp *l)
{
	/* everything will be done when the queueing scheme is attached. */
	return 0;
}

int
priqclose(dev_t dev, int flag, int fmt,
    struct lwp *l)
{
	struct priq_if *pif;
	int err, error = 0;

	while ((pif = pif_list) != NULL) {
		/* destroy all */
		if (ALTQ_IS_ENABLED(pif->pif_ifq))
			altq_disable(pif->pif_ifq);

		err = altq_detach(pif->pif_ifq);
		if (err == 0)
			err = priq_detach(pif);
		if (err != 0 && error == 0)
			error = err;
	}

	return error;
}

int
priqioctl(dev_t dev, ioctlcmd_t cmd, void *addr, int flag,
    struct lwp *l)
{
	struct priq_if *pif;
	struct priq_interface *ifacep;
	int	error = 0;

	/* check super-user privilege */
	switch (cmd) {
	case PRIQ_GETSTATS:
		break;
	default:
#if (__FreeBSD_version > 400000)
		if ((error = suser(p)) != 0)
			return (error);
#else
		if ((error = kauth_authorize_network(l->l_cred,
		    KAUTH_NETWORK_ALTQ, KAUTH_REQ_NETWORK_ALTQ_PRIQ, NULL,
		    NULL, NULL)) != 0)
			return (error);
#endif
		break;
	}

	switch (cmd) {

	case PRIQ_IF_ATTACH:
		error = priqcmd_if_attach((struct priq_interface *)addr);
		break;

	case PRIQ_IF_DETACH:
		error = priqcmd_if_detach((struct priq_interface *)addr);
		break;

	case PRIQ_ENABLE:
	case PRIQ_DISABLE:
	case PRIQ_CLEAR:
		ifacep = (struct priq_interface *)addr;
		if ((pif = altq_lookup(ifacep->ifname,
				       ALTQT_PRIQ)) == NULL) {
			error = EBADF;
			break;
		}

		switch (cmd) {
		case PRIQ_ENABLE:
			if (pif->pif_default == NULL) {
#ifdef ALTQ_DEBUG
				printf("priq: no default class\n");
#endif
				error = EINVAL;
				break;
			}
			error = altq_enable(pif->pif_ifq);
			break;

		case PRIQ_DISABLE:
			error = altq_disable(pif->pif_ifq);
			break;

		case PRIQ_CLEAR:
			priq_clear_interface(pif);
			break;
		}
		break;

	case PRIQ_ADD_CLASS:
		error = priqcmd_add_class((struct priq_add_class *)addr);
		break;

	case PRIQ_DEL_CLASS:
		error = priqcmd_delete_class((struct priq_delete_class *)addr);
		break;

	case PRIQ_MOD_CLASS:
		error = priqcmd_modify_class((struct priq_modify_class *)addr);
		break;

	case PRIQ_ADD_FILTER:
		error = priqcmd_add_filter((struct priq_add_filter *)addr);
		break;

	case PRIQ_DEL_FILTER:
		error = priqcmd_delete_filter((struct priq_delete_filter *)addr);
		break;

	case PRIQ_GETSTATS:
		error = priqcmd_class_stats((struct priq_class_stats *)addr);
		break;

	default:
		error = EINVAL;
		break;
	}
	return error;
}

static int
priqcmd_if_attach(struct priq_interface *ap)
{
	struct priq_if *pif;
	struct ifnet *ifp;
	int error;

	if ((ifp = ifunit(ap->ifname)) == NULL)
		return (ENXIO);

	if ((pif = priq_attach(&ifp->if_snd, ap->arg)) == NULL)
		return (ENOMEM);

	/*
	 * set PRIQ to this ifnet structure.
	 */
	if ((error = altq_attach(&ifp->if_snd, ALTQT_PRIQ, pif,
				 priq_enqueue, priq_dequeue, priq_request,
				 &pif->pif_classifier, acc_classify)) != 0)
		(void)priq_detach(pif);

	return (error);
}

static int
priqcmd_if_detach(struct priq_interface *ap)
{
	struct priq_if *pif;
	int error;

	if ((pif = altq_lookup(ap->ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	if (ALTQ_IS_ENABLED(pif->pif_ifq))
		altq_disable(pif->pif_ifq);

	if ((error = altq_detach(pif->pif_ifq)))
		return (error);

	return priq_detach(pif);
}

static int
priqcmd_add_class(struct priq_add_class *ap)
{
	struct priq_if *pif;
	struct priq_class *cl;
	int qid;

	if ((pif = altq_lookup(ap->iface.ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	if (ap->pri < 0 || ap->pri >= PRIQ_MAXPRI)
		return (EINVAL);
	if (pif->pif_classes[ap->pri] != NULL)
		return (EBUSY);

	qid = ap->pri + 1;
	if ((cl = priq_class_create(pif, ap->pri,
	    ap->qlimit, ap->flags, qid)) == NULL)
		return (ENOMEM);

	/* return a class handle to the user */
	ap->class_handle = cl->cl_handle;

	return (0);
}

static int
priqcmd_delete_class(struct priq_delete_class *ap)
{
	struct priq_if *pif;
	struct priq_class *cl;

	if ((pif = altq_lookup(ap->iface.ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	if ((cl = clh_to_clp(pif, ap->class_handle)) == NULL)
		return (EINVAL);

	return priq_class_destroy(cl);
}

static int
priqcmd_modify_class(struct priq_modify_class *ap)
{
	struct priq_if *pif;
	struct priq_class *cl;

	if ((pif = altq_lookup(ap->iface.ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	if (ap->pri < 0 || ap->pri >= PRIQ_MAXPRI)
		return (EINVAL);

	if ((cl = clh_to_clp(pif, ap->class_handle)) == NULL)
		return (EINVAL);

	/*
	 * if priority is changed, move the class to the new priority
	 */
	if (pif->pif_classes[ap->pri] != cl) {
		if (pif->pif_classes[ap->pri] != NULL)
			return (EEXIST);
		pif->pif_classes[cl->cl_pri] = NULL;
		pif->pif_classes[ap->pri] = cl;
		cl->cl_pri = ap->pri;
	}

	/* call priq_class_create to change class parameters */
	if ((cl = priq_class_create(pif, ap->pri,
	    ap->qlimit, ap->flags, ap->class_handle)) == NULL)
		return (ENOMEM);
	return 0;
}

static int
priqcmd_add_filter(struct priq_add_filter *ap)
{
	struct priq_if *pif;
	struct priq_class *cl;

	if ((pif = altq_lookup(ap->iface.ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	if ((cl = clh_to_clp(pif, ap->class_handle)) == NULL)
		return (EINVAL);

	return acc_add_filter(&pif->pif_classifier, &ap->filter,
			      cl, &ap->filter_handle);
}

static int
priqcmd_delete_filter(struct priq_delete_filter *ap)
{
	struct priq_if *pif;

	if ((pif = altq_lookup(ap->iface.ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	return acc_delete_filter(&pif->pif_classifier,
				 ap->filter_handle);
}

static int
priqcmd_class_stats(struct priq_class_stats *ap)
{
	struct priq_if *pif;
	struct priq_class *cl;
	struct priq_classstats stats, *usp;
	int	pri, error;

	if ((pif = altq_lookup(ap->iface.ifname, ALTQT_PRIQ)) == NULL)
		return (EBADF);

	ap->maxpri = pif->pif_maxpri;

	/* then, read the next N classes in the tree */
	usp = ap->stats;
	for (pri = 0; pri <= pif->pif_maxpri; pri++) {
		cl = pif->pif_classes[pri];
		if (cl != NULL)
			get_class_stats(&stats, cl);
		else
			memset(&stats, 0, sizeof(stats));
		if ((error = copyout((void *)&stats, (void *)usp++,
				     sizeof(stats))) != 0)
			return (error);
	}
	return (0);
}

#ifdef KLD_MODULE

static struct altqsw priq_sw =
	{"priq", priqopen, priqclose, priqioctl};

ALTQ_MODULE(altq_priq, ALTQT_PRIQ, &priq_sw);
MODULE_DEPEND(altq_priq, altq_red, 1, 1, 1);
MODULE_DEPEND(altq_priq, altq_rio, 1, 1, 1);

#endif /* KLD_MODULE */

#endif /* ALTQ3_COMPAT */
#endif /* ALTQ_PRIQ */