/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1989, 1993
 *      The 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. Neither the name of the University nor the names of its contributors
 *    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/param.h>
#include <sys/socket.h>

#ifndef ALTQ
#define ALTQ    /* Needed for ifq.h prototypes only. */
#endif

#include <net/if.h>
#include <net/if_var.h>
#include <net/if_private.h>
#include <net/ifq.h>

int
drbr_enqueue(struct ifnet *ifp, struct buf_ring *br, struct mbuf *m)
{
        int error = 0;

        if (ALTQ_IS_ENABLED(&ifp->if_snd)) {
                IFQ_ENQUEUE(&ifp->if_snd, m, error);
                if (error)
                        if_inc_counter((ifp), IFCOUNTER_OQDROPS, 1);
                return (error);
        }
        error = buf_ring_enqueue(br, m);
        if (error)
                m_freem(m);

        return (error);
}

void
drbr_putback(struct ifnet *ifp, struct buf_ring *br, struct mbuf *m_new)
{
        /*
         * The top of the list needs to be swapped
         * for this one.
         */
        if (ifp != NULL && ALTQ_IS_ENABLED(&ifp->if_snd)) {
                /*
                 * Peek in altq case dequeued it
                 * so put it back.
                 */
                IFQ_DRV_PREPEND(&ifp->if_snd, m_new);
                return;
        }
        buf_ring_putback_sc(br, m_new);
}

struct mbuf *
drbr_peek(struct ifnet *ifp, struct buf_ring *br)
{
        struct mbuf *m;
        if (ifp != NULL && ALTQ_IS_ENABLED(&ifp->if_snd)) {
                /*
                 * Pull it off like a dequeue
                 * since drbr_advance() does nothing
                 * for altq and drbr_putback() will
                 * use the old prepend function.
                 */
                IFQ_DEQUEUE(&ifp->if_snd, m);
                return (m);
        }
        return ((struct mbuf *)buf_ring_peek_clear_sc(br));
}

void
drbr_flush(struct ifnet *ifp, struct buf_ring *br)
{
        struct mbuf *m;

        if (ifp != NULL && ALTQ_IS_ENABLED(&ifp->if_snd))
                IFQ_PURGE(&ifp->if_snd);
        while ((m = (struct mbuf *)buf_ring_dequeue_sc(br)) != NULL)
                m_freem(m);
}

struct mbuf *
drbr_dequeue(struct ifnet *ifp, struct buf_ring *br)
{
        struct mbuf *m;

        if (ifp != NULL && ALTQ_IS_ENABLED(&ifp->if_snd)) {
                IFQ_DEQUEUE(&ifp->if_snd, m);
                return (m);
        }
        return ((struct mbuf *)buf_ring_dequeue_sc(br));
}

void
drbr_advance(struct ifnet *ifp, struct buf_ring *br)
{
        /* Nothing to do here since peek dequeues in altq case */
        if (ifp != NULL && ALTQ_IS_ENABLED(&ifp->if_snd))
                return;
        return (buf_ring_advance_sc(br));
}

struct mbuf *
drbr_dequeue_cond(struct ifnet *ifp, struct buf_ring *br,
    int (*func) (struct mbuf *, void *), void *arg)
{
        struct mbuf *m;
        if (ALTQ_IS_ENABLED(&ifp->if_snd)) {
                IFQ_LOCK(&ifp->if_snd);
                IFQ_POLL_NOLOCK(&ifp->if_snd, m);
                if (m != NULL && func(m, arg) == 0) {
                        IFQ_UNLOCK(&ifp->if_snd);
                        return (NULL);
                }
                IFQ_DEQUEUE_NOLOCK(&ifp->if_snd, m);
                IFQ_UNLOCK(&ifp->if_snd);
                return (m);
        }
        m = (struct mbuf *)buf_ring_peek(br);
        if (m == NULL || func(m, arg) == 0)
                return (NULL);

        return ((struct mbuf *)buf_ring_dequeue_sc(br));
}

int
drbr_empty(struct ifnet *ifp, struct buf_ring *br)
{
        if (ALTQ_IS_ENABLED(&ifp->if_snd))
                return (IFQ_IS_EMPTY(&ifp->if_snd));
        return (buf_ring_empty(br));
}

int
drbr_needs_enqueue(struct ifnet *ifp, struct buf_ring *br)
{
        if (ALTQ_IS_ENABLED(&ifp->if_snd))
                return (1);
        return (!buf_ring_empty(br));
}

int
drbr_inuse(struct ifnet *ifp, struct buf_ring *br)
{
        if (ALTQ_IS_ENABLED(&ifp->if_snd))
                return (ifp->if_snd.ifq_len);
        return (buf_ring_count(br));
}