Create releng/7.2 from stable/7 in preparation for 7.2-RELEASE.

[FreeBSD/releng/7.2.git] / sys / netinet / ip_dummynet.c

/*-
 * Copyright (c) 1998-2002 Luigi Rizzo, Universita` di Pisa
 * Portions Copyright (c) 2000 Akamba Corp.
 * 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 THE AUTHOR 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 AUTHOR 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>
__FBSDID("$FreeBSD$");

#define DUMMYNET_DEBUG

#include "opt_inet6.h"

/*
 * This module implements IP dummynet, a bandwidth limiter/delay emulator
 * used in conjunction with the ipfw package.
 * Description of the data structures used is in ip_dummynet.h
 * Here you mainly find the following blocks of code:
 *  + variable declarations;
 *  + heap management functions;
 *  + scheduler and dummynet functions;
 *  + configuration and initialization.
 *
 * NOTA BENE: critical sections are protected by the "dummynet lock".
 *
 * Most important Changes:
 *
 * 011004: KLDable
 * 010124: Fixed WF2Q behaviour
 * 010122: Fixed spl protection.
 * 000601: WF2Q support
 * 000106: large rewrite, use heaps to handle very many pipes.
 * 980513:      initial release
 *
 * include files marked with XXX are probably not needed
 */

#include <sys/limits.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/time.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>
#include <net/if.h>     /* IFNAMSIZ, struct ifaddr, ifq head */
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/ip.h> /* ip_len, ip_off */
#include <netinet/ip_fw.h>
#include <netinet/ip_dummynet.h>
#include <netinet/ip_var.h>     /* ip_output(), IP_FORWARDING */

#include <netinet/if_ether.h> /* various ether_* routines */

#include <netinet/ip6.h>       /* for ip6_input, ip6_output prototypes */
#include <netinet6/ip6_var.h>

/*
 * We keep a private variable for the simulation time, but we could
 * probably use an existing one ("softticks" in sys/kern/kern_timeout.c)
 */
static dn_key curr_time = 0 ; /* current simulation time */

static int dn_hash_size = 64 ;  /* default hash size */

/* statistics on number of queue searches and search steps */
static long searches, search_steps ;
static int pipe_expire = 1 ;   /* expire queue if empty */
static int dn_max_ratio = 16 ; /* max queues/buckets ratio */

static long pipe_slot_limit = 100; /* Foot shooting limit for pipe queues. */
static long pipe_byte_limit = 1024 * 1024;

static int red_lookup_depth = 256;      /* RED - default lookup table depth */
static int red_avg_pkt_size = 512;      /* RED - default medium packet size */
static int red_max_pkt_size = 1500;     /* RED - default max packet size */

static struct timeval prev_t, t;
static long tick_last;                  /* Last tick duration (usec). */
static long tick_delta;                 /* Last vs standard tick diff (usec). */
static long tick_delta_sum;             /* Accumulated tick difference (usec).*/
static long tick_adjustment;            /* Tick adjustments done. */
static long tick_lost;                  /* Lost(coalesced) ticks number. */
/* Adjusted vs non-adjusted curr_time difference (ticks). */
static long tick_diff;

static int              io_fast;
static unsigned long    io_pkt;
static unsigned long    io_pkt_fast;
static unsigned long    io_pkt_drop;

/*
 * Three heaps contain queues and pipes that the scheduler handles:
 *
 * ready_heap contains all dn_flow_queue related to fixed-rate pipes.
 *
 * wfq_ready_heap contains the pipes associated with WF2Q flows
 *
 * extract_heap contains pipes associated with delay lines.
 *
 */

MALLOC_DEFINE(M_DUMMYNET, "dummynet", "dummynet heap");

static struct dn_heap ready_heap, extract_heap, wfq_ready_heap ;

static int      heap_init(struct dn_heap *h, int size);
static int      heap_insert (struct dn_heap *h, dn_key key1, void *p);
static void     heap_extract(struct dn_heap *h, void *obj);
static void     transmit_event(struct dn_pipe *pipe, struct mbuf **head,
                    struct mbuf **tail);
static void     ready_event(struct dn_flow_queue *q, struct mbuf **head,
                    struct mbuf **tail);
static void     ready_event_wfq(struct dn_pipe *p, struct mbuf **head,
                    struct mbuf **tail);

#define HASHSIZE        16
#define HASH(num)       ((((num) >> 8) ^ ((num) >> 4) ^ (num)) & 0x0f)
static struct dn_pipe_head      pipehash[HASHSIZE];     /* all pipes */
static struct dn_flow_set_head  flowsethash[HASHSIZE];  /* all flowsets */

static struct callout dn_timeout;

extern  void (*bridge_dn_p)(struct mbuf *, struct ifnet *);

#ifdef SYSCTL_NODE
SYSCTL_DECL(_net_inet);
SYSCTL_DECL(_net_inet_ip);

SYSCTL_NODE(_net_inet_ip, OID_AUTO, dummynet, CTLFLAG_RW, 0, "Dummynet");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, hash_size,
    CTLFLAG_RW, &dn_hash_size, 0, "Default hash table size");
#if 0 /* curr_time is 64 bit */
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, curr_time,
    CTLFLAG_RD, &curr_time, 0, "Current tick");
#endif
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, ready_heap,
    CTLFLAG_RD, &ready_heap.size, 0, "Size of ready heap");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, extract_heap,
    CTLFLAG_RD, &extract_heap.size, 0, "Size of extract heap");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, searches,
    CTLFLAG_RD, &searches, 0, "Number of queue searches");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, search_steps,
    CTLFLAG_RD, &search_steps, 0, "Number of queue search steps");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, expire,
    CTLFLAG_RW, &pipe_expire, 0, "Expire queue if empty");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, max_chain_len,
    CTLFLAG_RW, &dn_max_ratio, 0,
    "Max ratio between dynamic queues and buckets");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, red_lookup_depth,
    CTLFLAG_RD, &red_lookup_depth, 0, "Depth of RED lookup table");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, red_avg_pkt_size,
    CTLFLAG_RD, &red_avg_pkt_size, 0, "RED Medium packet size");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, red_max_pkt_size,
    CTLFLAG_RD, &red_max_pkt_size, 0, "RED Max packet size");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_delta,
    CTLFLAG_RD, &tick_delta, 0, "Last vs standard tick difference (usec).");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_delta_sum,
    CTLFLAG_RD, &tick_delta_sum, 0, "Accumulated tick difference (usec).");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_adjustment,
    CTLFLAG_RD, &tick_adjustment, 0, "Tick adjustments done.");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_diff,
    CTLFLAG_RD, &tick_diff, 0,
    "Adjusted vs non-adjusted curr_time difference (ticks).");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_lost,
    CTLFLAG_RD, &tick_lost, 0,
    "Number of ticks coalesced by dummynet taskqueue.");
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, io_fast,
    CTLFLAG_RW, &io_fast, 0, "Enable fast dummynet io.");
SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt,
    CTLFLAG_RD, &io_pkt, 0,
    "Number of packets passed to dummynet.");
SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt_fast,
    CTLFLAG_RD, &io_pkt_fast, 0,
    "Number of packets bypassed dummynet scheduler.");
SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt_drop,
    CTLFLAG_RD, &io_pkt_drop, 0,
    "Number of packets dropped by dummynet.");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, pipe_slot_limit,
    CTLFLAG_RW, &pipe_slot_limit, 0, "Upper limit in slots for pipe queue.");
SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, pipe_byte_limit,
    CTLFLAG_RW, &pipe_byte_limit, 0, "Upper limit in bytes for pipe queue.");
#endif

#ifdef DUMMYNET_DEBUG
int     dummynet_debug = 0;
#ifdef SYSCTL_NODE
SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, debug, CTLFLAG_RW, &dummynet_debug,
            0, "control debugging printfs");
#endif
#define DPRINTF(X)      if (dummynet_debug) printf X
#else
#define DPRINTF(X)
#endif

static struct task      dn_task;
static struct taskqueue *dn_tq = NULL;
static void dummynet_task(void *, int);

static struct mtx dummynet_mtx;
#define DUMMYNET_LOCK_INIT() \
        mtx_init(&dummynet_mtx, "dummynet", NULL, MTX_DEF)
#define DUMMYNET_LOCK_DESTROY() mtx_destroy(&dummynet_mtx)
#define DUMMYNET_LOCK()         mtx_lock(&dummynet_mtx)
#define DUMMYNET_UNLOCK()       mtx_unlock(&dummynet_mtx)
#define DUMMYNET_LOCK_ASSERT()  mtx_assert(&dummynet_mtx, MA_OWNED)

static int      config_pipe(struct dn_pipe *p);
static int      ip_dn_ctl(struct sockopt *sopt);

static void     dummynet(void *);
static void     dummynet_flush(void);
static void     dummynet_send(struct mbuf *);
void            dummynet_drain(void);
static ip_dn_io_t dummynet_io;
static void     dn_rule_delete(void *);

/*
 * Heap management functions.
 *
 * In the heap, first node is element 0. Children of i are 2i+1 and 2i+2.
 * Some macros help finding parent/children so we can optimize them.
 *
 * heap_init() is called to expand the heap when needed.
 * Increment size in blocks of 16 entries.
 * XXX failure to allocate a new element is a pretty bad failure
 * as we basically stall a whole queue forever!!
 * Returns 1 on error, 0 on success
 */
#define HEAP_FATHER(x) ( ( (x) - 1 ) / 2 )
#define HEAP_LEFT(x) ( 2*(x) + 1 )
#define HEAP_IS_LEFT(x) ( (x) & 1 )
#define HEAP_RIGHT(x) ( 2*(x) + 2 )
#define HEAP_SWAP(a, b, buffer) { buffer = a ; a = b ; b = buffer ; }
#define HEAP_INCREMENT  15

static int
heap_init(struct dn_heap *h, int new_size)
{
    struct dn_heap_entry *p;

    if (h->size >= new_size ) {
        printf("dummynet: %s, Bogus call, have %d want %d\n", __func__,
                h->size, new_size);
        return 0 ;
    }
    new_size = (new_size + HEAP_INCREMENT ) & ~HEAP_INCREMENT ;
    p = malloc(new_size * sizeof(*p), M_DUMMYNET, M_NOWAIT);
    if (p == NULL) {
        printf("dummynet: %s, resize %d failed\n", __func__, new_size );
        return 1 ; /* error */
    }
    if (h->size > 0) {
        bcopy(h->p, p, h->size * sizeof(*p) );
        free(h->p, M_DUMMYNET);
    }
    h->p = p ;
    h->size = new_size ;
    return 0 ;
}

/*
 * Insert element in heap. Normally, p != NULL, we insert p in
 * a new position and bubble up. If p == NULL, then the element is
 * already in place, and key is the position where to start the
 * bubble-up.
 * Returns 1 on failure (cannot allocate new heap entry)
 *
 * If offset > 0 the position (index, int) of the element in the heap is
 * also stored in the element itself at the given offset in bytes.
 */
#define SET_OFFSET(heap, node) \
    if (heap->offset > 0) \
            *((int *)((char *)(heap->p[node].object) + heap->offset)) = node ;
/*
 * RESET_OFFSET is used for sanity checks. It sets offset to an invalid value.
 */
#define RESET_OFFSET(heap, node) \
    if (heap->offset > 0) \
            *((int *)((char *)(heap->p[node].object) + heap->offset)) = -1 ;
static int
heap_insert(struct dn_heap *h, dn_key key1, void *p)
{
    int son = h->elements ;

    if (p == NULL)      /* data already there, set starting point */
        son = key1 ;
    else {              /* insert new element at the end, possibly resize */
        son = h->elements ;
        if (son == h->size) /* need resize... */
            if (heap_init(h, h->elements+1) )
                return 1 ; /* failure... */
        h->p[son].object = p ;
        h->p[son].key = key1 ;
        h->elements++ ;
    }
    while (son > 0) {                           /* bubble up */
        int father = HEAP_FATHER(son) ;
        struct dn_heap_entry tmp  ;

        if (DN_KEY_LT( h->p[father].key, h->p[son].key ) )
            break ; /* found right position */
        /* son smaller than father, swap and repeat */
        HEAP_SWAP(h->p[son], h->p[father], tmp) ;
        SET_OFFSET(h, son);
        son = father ;
    }
    SET_OFFSET(h, son);
    return 0 ;
}

/*
 * remove top element from heap, or obj if obj != NULL
 */
static void
heap_extract(struct dn_heap *h, void *obj)
{
    int child, father, max = h->elements - 1 ;

    if (max < 0) {
        printf("dummynet: warning, extract from empty heap 0x%p\n", h);
        return ;
    }
    father = 0 ; /* default: move up smallest child */
    if (obj != NULL) { /* extract specific element, index is at offset */
        if (h->offset <= 0)
            panic("dummynet: heap_extract from middle not supported on this heap!!!\n");
        father = *((int *)((char *)obj + h->offset)) ;
        if (father < 0 || father >= h->elements) {
            printf("dummynet: heap_extract, father %d out of bound 0..%d\n",
                father, h->elements);
            panic("dummynet: heap_extract");
        }
    }
    RESET_OFFSET(h, father);
    child = HEAP_LEFT(father) ;         /* left child */
    while (child <= max) {              /* valid entry */
        if (child != max && DN_KEY_LT(h->p[child+1].key, h->p[child].key) )
            child = child+1 ;           /* take right child, otherwise left */
        h->p[father] = h->p[child] ;
        SET_OFFSET(h, father);
        father = child ;
        child = HEAP_LEFT(child) ;   /* left child for next loop */
    }
    h->elements-- ;
    if (father != max) {
        /*
         * Fill hole with last entry and bubble up, reusing the insert code
         */
        h->p[father] = h->p[max] ;
        heap_insert(h, father, NULL); /* this one cannot fail */
    }
}

#if 0
/*
 * change object position and update references
 * XXX this one is never used!
 */
static void
heap_move(struct dn_heap *h, dn_key new_key, void *object)
{
    int temp;
    int i ;
    int max = h->elements-1 ;
    struct dn_heap_entry buf ;

    if (h->offset <= 0)
        panic("cannot move items on this heap");

    i = *((int *)((char *)object + h->offset));
    if (DN_KEY_LT(new_key, h->p[i].key) ) { /* must move up */
        h->p[i].key = new_key ;
        for (; i>0 && DN_KEY_LT(new_key, h->p[(temp = HEAP_FATHER(i))].key) ;
                 i = temp ) { /* bubble up */
            HEAP_SWAP(h->p[i], h->p[temp], buf) ;
            SET_OFFSET(h, i);
        }
    } else {            /* must move down */
        h->p[i].key = new_key ;
        while ( (temp = HEAP_LEFT(i)) <= max ) { /* found left child */
            if ((temp != max) && DN_KEY_GT(h->p[temp].key, h->p[temp+1].key))
                temp++ ; /* select child with min key */
            if (DN_KEY_GT(new_key, h->p[temp].key)) { /* go down */
                HEAP_SWAP(h->p[i], h->p[temp], buf) ;
                SET_OFFSET(h, i);
            } else
                break ;
            i = temp ;
        }
    }
    SET_OFFSET(h, i);
}
#endif /* heap_move, unused */

/*
 * heapify() will reorganize data inside an array to maintain the
 * heap property. It is needed when we delete a bunch of entries.
 */
static void
heapify(struct dn_heap *h)
{
    int i ;

    for (i = 0 ; i < h->elements ; i++ )
        heap_insert(h, i , NULL) ;
}

/*
 * cleanup the heap and free data structure
 */
static void
heap_free(struct dn_heap *h)
{
    if (h->size >0 )
        free(h->p, M_DUMMYNET);
    bzero(h, sizeof(*h) );
}

/*
 * --- end of heap management functions ---
 */

/*
 * Return the mbuf tag holding the dummynet state.  As an optimization
 * this is assumed to be the first tag on the list.  If this turns out
 * wrong we'll need to search the list.
 */
static struct dn_pkt_tag *
dn_tag_get(struct mbuf *m)
{
    struct m_tag *mtag = m_tag_first(m);
    KASSERT(mtag != NULL &&
            mtag->m_tag_cookie == MTAG_ABI_COMPAT &&
            mtag->m_tag_id == PACKET_TAG_DUMMYNET,
            ("packet on dummynet queue w/o dummynet tag!"));
    return (struct dn_pkt_tag *)(mtag+1);
}

/*
 * Scheduler functions:
 *
 * transmit_event() is called when the delay-line needs to enter
 * the scheduler, either because of existing pkts getting ready,
 * or new packets entering the queue. The event handled is the delivery
 * time of the packet.
 *
 * ready_event() does something similar with fixed-rate queues, and the
 * event handled is the finish time of the head pkt.
 *
 * wfq_ready_event() does something similar with WF2Q queues, and the
 * event handled is the start time of the head pkt.
 *
 * In all cases, we make sure that the data structures are consistent
 * before passing pkts out, because this might trigger recursive
 * invocations of the procedures.
 */
static void
transmit_event(struct dn_pipe *pipe, struct mbuf **head, struct mbuf **tail)
{
        struct mbuf *m;
        struct dn_pkt_tag *pkt;

        DUMMYNET_LOCK_ASSERT();

        while ((m = pipe->head) != NULL) {
                pkt = dn_tag_get(m);
                if (!DN_KEY_LEQ(pkt->output_time, curr_time))
                        break;

                pipe->head = m->m_nextpkt;
                if (*tail != NULL)
                        (*tail)->m_nextpkt = m;
                else
                        *head = m;
                *tail = m;
        }
        if (*tail != NULL)
                (*tail)->m_nextpkt = NULL;

        /* If there are leftover packets, put into the heap for next event. */
        if ((m = pipe->head) != NULL) {
                pkt = dn_tag_get(m);
                /*
                 * XXX Should check errors on heap_insert, by draining the
                 * whole pipe p and hoping in the future we are more successful.
                 */
                heap_insert(&extract_heap, pkt->output_time, pipe);
        }
}

/*
 * the following macro computes how many ticks we have to wait
 * before being able to transmit a packet. The credit is taken from
 * either a pipe (WF2Q) or a flow_queue (per-flow queueing)
 */
#define SET_TICKS(_m, q, p)     \
    ((_m)->m_pkthdr.len * 8 * hz - (q)->numbytes + p->bandwidth - 1) / \
    p->bandwidth;

/*
 * extract pkt from queue, compute output time (could be now)
 * and put into delay line (p_queue)
 */
static void
move_pkt(struct mbuf *pkt, struct dn_flow_queue *q, struct dn_pipe *p,
    int len)
{
    struct dn_pkt_tag *dt = dn_tag_get(pkt);

    q->head = pkt->m_nextpkt ;
    q->len-- ;
    q->len_bytes -= len ;

    dt->output_time = curr_time + p->delay ;

    if (p->head == NULL)
        p->head = pkt;
    else
        p->tail->m_nextpkt = pkt;
    p->tail = pkt;
    p->tail->m_nextpkt = NULL;
}

/*
 * ready_event() is invoked every time the queue must enter the
 * scheduler, either because the first packet arrives, or because
 * a previously scheduled event fired.
 * On invokation, drain as many pkts as possible (could be 0) and then
 * if there are leftover packets reinsert the pkt in the scheduler.
 */
static void
ready_event(struct dn_flow_queue *q, struct mbuf **head, struct mbuf **tail)
{
        struct mbuf *pkt;
        struct dn_pipe *p = q->fs->pipe;
        int p_was_empty;

        DUMMYNET_LOCK_ASSERT();

        if (p == NULL) {
                printf("dummynet: ready_event- pipe is gone\n");
                return;
        }
        p_was_empty = (p->head == NULL);

        /*
         * Schedule fixed-rate queues linked to this pipe:
         * account for the bw accumulated since last scheduling, then
         * drain as many pkts as allowed by q->numbytes and move to
         * the delay line (in p) computing output time.
         * bandwidth==0 (no limit) means we can drain the whole queue,
         * setting len_scaled = 0 does the job.
         */
        q->numbytes += (curr_time - q->sched_time) * p->bandwidth;
        while ((pkt = q->head) != NULL) {
                int len = pkt->m_pkthdr.len;
                int len_scaled = p->bandwidth ? len * 8 * hz : 0;

                if (len_scaled > q->numbytes)
                        break;
                q->numbytes -= len_scaled;
                move_pkt(pkt, q, p, len);
        }
        /*
         * If we have more packets queued, schedule next ready event
         * (can only occur when bandwidth != 0, otherwise we would have
         * flushed the whole queue in the previous loop).
         * To this purpose we record the current time and compute how many
         * ticks to go for the finish time of the packet.
         */
        if ((pkt = q->head) != NULL) {  /* this implies bandwidth != 0 */
                dn_key t = SET_TICKS(pkt, q, p); /* ticks i have to wait */

                q->sched_time = curr_time;
                heap_insert(&ready_heap, curr_time + t, (void *)q);
                /*
                 * XXX Should check errors on heap_insert, and drain the whole
                 * queue on error hoping next time we are luckier.
                 */
        } else          /* RED needs to know when the queue becomes empty. */
                q->q_time = curr_time;

        /*
         * If the delay line was empty call transmit_event() now.
         * Otherwise, the scheduler will take care of it.
         */
        if (p_was_empty)
                transmit_event(p, head, tail);
}

/*
 * Called when we can transmit packets on WF2Q queues. Take pkts out of
 * the queues at their start time, and enqueue into the delay line.
 * Packets are drained until p->numbytes < 0. As long as
 * len_scaled >= p->numbytes, the packet goes into the delay line
 * with a deadline p->delay. For the last packet, if p->numbytes < 0,
 * there is an additional delay.
 */
static void
ready_event_wfq(struct dn_pipe *p, struct mbuf **head, struct mbuf **tail)
{
        int p_was_empty = (p->head == NULL);
        struct dn_heap *sch = &(p->scheduler_heap);
        struct dn_heap *neh = &(p->not_eligible_heap);
        int64_t p_numbytes = p->numbytes;

        DUMMYNET_LOCK_ASSERT();

        if (p->if_name[0] == 0)         /* tx clock is simulated */
                /*
                 * Since result may not fit into p->numbytes (32bit) we
                 * are using 64bit var here.
                 */
                p_numbytes += (curr_time - p->sched_time) * p->bandwidth;
        else {  /*
                 * tx clock is for real,
                 * the ifq must be empty or this is a NOP.
                 */
                if (p->ifp && p->ifp->if_snd.ifq_head != NULL)
                        return;
                else {
                        DPRINTF(("dummynet: pipe %d ready from %s --\n",
                            p->pipe_nr, p->if_name));
                }
        }

        /*
         * While we have backlogged traffic AND credit, we need to do
         * something on the queue.
         */
        while (p_numbytes >= 0 && (sch->elements > 0 || neh->elements > 0)) {
                if (sch->elements > 0) {
                        /* Have some eligible pkts to send out. */
                        struct dn_flow_queue *q = sch->p[0].object;
                        struct mbuf *pkt = q->head;
                        struct dn_flow_set *fs = q->fs;
                        uint64_t len = pkt->m_pkthdr.len;
                        int len_scaled = p->bandwidth ? len * 8 * hz : 0;

                        heap_extract(sch, NULL); /* Remove queue from heap. */
                        p_numbytes -= len_scaled;
                        move_pkt(pkt, q, p, len);

                        p->V += (len << MY_M) / p->sum; /* Update V. */
                        q->S = q->F;                    /* Update start time. */
                        if (q->len == 0) {
                                /* Flow not backlogged any more. */
                                fs->backlogged--;
                                heap_insert(&(p->idle_heap), q->F, q);
                        } else {
                                /* Still backlogged. */

                                /*
                                 * Update F and position in backlogged queue,
                                 * then put flow in not_eligible_heap
                                 * (we will fix this later).
                                 */
                                len = (q->head)->m_pkthdr.len;
                                q->F += (len << MY_M) / (uint64_t)fs->weight;
                                if (DN_KEY_LEQ(q->S, p->V))
                                        heap_insert(neh, q->S, q);
                                else
                                        heap_insert(sch, q->F, q);
                        }
                }
                /*
                 * Now compute V = max(V, min(S_i)). Remember that all elements
                 * in sch have by definition S_i <= V so if sch is not empty,
                 * V is surely the max and we must not update it. Conversely,
                 * if sch is empty we only need to look at neh.
                 */
                if (sch->elements == 0 && neh->elements > 0)
                        p->V = MAX64(p->V, neh->p[0].key);
                /* Move from neh to sch any packets that have become eligible */
                while (neh->elements > 0 && DN_KEY_LEQ(neh->p[0].key, p->V)) {
                        struct dn_flow_queue *q = neh->p[0].object;
                        heap_extract(neh, NULL);
                        heap_insert(sch, q->F, q);
                }

                if (p->if_name[0] != '\0') { /* Tx clock is from a real thing */
                        p_numbytes = -1;        /* Mark not ready for I/O. */
                        break;
                }
        }
        if (sch->elements == 0 && neh->elements == 0 && p_numbytes >= 0 &&
            p->idle_heap.elements > 0) {
                /*
                 * No traffic and no events scheduled.
                 * We can get rid of idle-heap.
                 */
                int i;

                for (i = 0; i < p->idle_heap.elements; i++) {
                        struct dn_flow_queue *q = p->idle_heap.p[i].object;

                        q->F = 0;
                        q->S = q->F + 1;
                }
                p->sum = 0;
                p->V = 0;
                p->idle_heap.elements = 0;
        }
        /*
         * If we are getting clocks from dummynet (not a real interface) and
         * If we are under credit, schedule the next ready event.
         * Also fix the delivery time of the last packet.
         */
        if (p->if_name[0]==0 && p_numbytes < 0) { /* This implies bw > 0. */
                dn_key t = 0;           /* Number of ticks i have to wait. */

                if (p->bandwidth > 0)
                        t = (p->bandwidth - 1 - p_numbytes) / p->bandwidth;
                dn_tag_get(p->tail)->output_time += t;
                p->sched_time = curr_time;
                heap_insert(&wfq_ready_heap, curr_time + t, (void *)p);
                /*
                 * XXX Should check errors on heap_insert, and drain the whole
                 * queue on error hoping next time we are luckier.
                 */
        }

        /* Fit (adjust if necessary) 64bit result into 32bit variable. */
        if (p_numbytes > INT_MAX)
                p->numbytes = INT_MAX;
        else if (p_numbytes < INT_MIN)
                p->numbytes = INT_MIN;
        else
                p->numbytes = p_numbytes;

        /*
         * If the delay line was empty call transmit_event() now.
         * Otherwise, the scheduler will take care of it.
         */
        if (p_was_empty)
                transmit_event(p, head, tail);
}

/*
 * This is called one tick, after previous run. It is used to
 * schedule next run.
 */
static void
dummynet(void * __unused unused)
{

        taskqueue_enqueue(dn_tq, &dn_task);
}

/*
 * The main dummynet processing function.
 */
static void
dummynet_task(void *context, int pending)
{
        struct mbuf *head = NULL, *tail = NULL;
        struct dn_pipe *pipe;
        struct dn_heap *heaps[3];
        struct dn_heap *h;
        void *p;        /* generic parameter to handler */
        int i;

        DUMMYNET_LOCK();

        heaps[0] = &ready_heap;                 /* fixed-rate queues */
        heaps[1] = &wfq_ready_heap;             /* wfq queues */
        heaps[2] = &extract_heap;               /* delay line */

        /* Update number of lost(coalesced) ticks. */
        tick_lost += pending - 1;
 
        getmicrouptime(&t);
        /* Last tick duration (usec). */
        tick_last = (t.tv_sec - prev_t.tv_sec) * 1000000 +
            (t.tv_usec - prev_t.tv_usec);
        /* Last tick vs standard tick difference (usec). */
        tick_delta = (tick_last * hz - 1000000) / hz;
        /* Accumulated tick difference (usec). */
        tick_delta_sum += tick_delta;
 
        prev_t = t;
 
        /*
         * Adjust curr_time if accumulated tick difference greater than
         * 'standard' tick. Since curr_time should be monotonically increasing,
         * we do positive adjustment as required and throttle curr_time in
         * case of negative adjustment.
         */
        curr_time++;
        if (tick_delta_sum - tick >= 0) {
                int diff = tick_delta_sum / tick;
 
                curr_time += diff;
                tick_diff += diff;
                tick_delta_sum %= tick;
                tick_adjustment++;
        } else if (tick_delta_sum + tick <= 0) {
                curr_time--;
                tick_diff--;
                tick_delta_sum += tick;
                tick_adjustment++;
        }

        for (i = 0; i < 3; i++) {
                h = heaps[i];
                while (h->elements > 0 && DN_KEY_LEQ(h->p[0].key, curr_time)) {
                        if (h->p[0].key > curr_time)
                                printf("dummynet: warning, "
                                    "heap %d is %d ticks late\n",
                                    i, (int)(curr_time - h->p[0].key));
                        /* store a copy before heap_extract */
                        p = h->p[0].object;
                        /* need to extract before processing */
                        heap_extract(h, NULL);
                        if (i == 0)
                                ready_event(p, &head, &tail);
                        else if (i == 1) {
                                struct dn_pipe *pipe = p;
                                if (pipe->if_name[0] != '\0')
                                        printf("dummynet: bad ready_event_wfq "
                                            "for pipe %s\n", pipe->if_name);
                                else
                                        ready_event_wfq(p, &head, &tail);
                        } else
                                transmit_event(p, &head, &tail);
                }
        }

        /* Sweep pipes trying to expire idle flow_queues. */
        for (i = 0; i < HASHSIZE; i++)
                SLIST_FOREACH(pipe, &pipehash[i], next)
                        if (pipe->idle_heap.elements > 0 &&
                            DN_KEY_LT(pipe->idle_heap.p[0].key, pipe->V)) {
                                struct dn_flow_queue *q =
                                    pipe->idle_heap.p[0].object;

                                heap_extract(&(pipe->idle_heap), NULL);
                                /* Mark timestamp as invalid. */
                                q->S = q->F + 1;
                                pipe->sum -= q->fs->weight;
                        }

        DUMMYNET_UNLOCK();

        if (head != NULL)
                dummynet_send(head);

        callout_reset(&dn_timeout, 1, dummynet, NULL);
}

static void
dummynet_send(struct mbuf *m)
{
        struct dn_pkt_tag *pkt;
        struct mbuf *n;
        struct ip *ip;

        for (; m != NULL; m = n) {
                n = m->m_nextpkt;
                m->m_nextpkt = NULL;
                pkt = dn_tag_get(m);
                switch (pkt->dn_dir) {
                case DN_TO_IP_OUT:
                        ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
                        break ;
                case DN_TO_IP_IN :
                        ip = mtod(m, struct ip *);
                        ip->ip_len = htons(ip->ip_len);
                        ip->ip_off = htons(ip->ip_off);
                        netisr_dispatch(NETISR_IP, m);
                        break;
#ifdef INET6
                case DN_TO_IP6_IN:
                        netisr_dispatch(NETISR_IPV6, m);
                        break;

                case DN_TO_IP6_OUT:
                        ip6_output(m, NULL, NULL, IPV6_FORWARDING, NULL, NULL, NULL);
                        break;
#endif
                case DN_TO_IFB_FWD:
                        if (bridge_dn_p != NULL)
                                ((*bridge_dn_p)(m, pkt->ifp));
                        else
                                printf("dummynet: if_bridge not loaded\n");

                        break;
                case DN_TO_ETH_DEMUX:
                        /*
                         * The Ethernet code assumes the Ethernet header is
                         * contiguous in the first mbuf header.
                         * Insure this is true.
                         */
                        if (m->m_len < ETHER_HDR_LEN &&
                            (m = m_pullup(m, ETHER_HDR_LEN)) == NULL) {
                                printf("dummynet/ether: pullup failed, "
                                    "dropping packet\n");
                                break;
                        }
                        ether_demux(m->m_pkthdr.rcvif, m);
                        break;
                case DN_TO_ETH_OUT:
                        ether_output_frame(pkt->ifp, m);
                        break;
                default:
                        printf("dummynet: bad switch %d!\n", pkt->dn_dir);
                        m_freem(m);
                        break;
                }
        }
}

/*
 * Unconditionally expire empty queues in case of shortage.
 * Returns the number of queues freed.
 */
static int
expire_queues(struct dn_flow_set *fs)
{
    struct dn_flow_queue *q, *prev ;
    int i, initial_elements = fs->rq_elements ;

    if (fs->last_expired == time_uptime)
        return 0 ;
    fs->last_expired = time_uptime ;
    for (i = 0 ; i <= fs->rq_size ; i++) /* last one is overflow */
        for (prev=NULL, q = fs->rq[i] ; q != NULL ; )
            if (q->head != NULL || q->S != q->F+1) {
                prev = q ;
                q = q->next ;
            } else { /* entry is idle, expire it */
                struct dn_flow_queue *old_q = q ;

                if (prev != NULL)
                    prev->next = q = q->next ;
                else
                    fs->rq[i] = q = q->next ;
                fs->rq_elements-- ;
                free(old_q, M_DUMMYNET);
            }
    return initial_elements - fs->rq_elements ;
}

/*
 * If room, create a new queue and put at head of slot i;
 * otherwise, create or use the default queue.
 */
static struct dn_flow_queue *
create_queue(struct dn_flow_set *fs, int i)
{
        struct dn_flow_queue *q;

        if (fs->rq_elements > fs->rq_size * dn_max_ratio &&
            expire_queues(fs) == 0) {
                /* No way to get room, use or create overflow queue. */
                i = fs->rq_size;
                if (fs->rq[i] != NULL)
                    return fs->rq[i];
        }
        q = malloc(sizeof(*q), M_DUMMYNET, M_NOWAIT | M_ZERO);
        if (q == NULL) {
                printf("dummynet: sorry, cannot allocate queue for new flow\n");
                return (NULL);
        }
        q->fs = fs;
        q->hash_slot = i;
        q->next = fs->rq[i];
        q->S = q->F + 1;        /* hack - mark timestamp as invalid. */
        q->numbytes = io_fast ? fs->pipe->bandwidth : 0;
        fs->rq[i] = q;
        fs->rq_elements++;
        return (q);
}

/*
 * Given a flow_set and a pkt in last_pkt, find a matching queue
 * after appropriate masking. The queue is moved to front
 * so that further searches take less time.
 */
static struct dn_flow_queue *
find_queue(struct dn_flow_set *fs, struct ipfw_flow_id *id)
{
    int i = 0 ; /* we need i and q for new allocations */
    struct dn_flow_queue *q, *prev;
    int is_v6 = IS_IP6_FLOW_ID(id);

    if ( !(fs->flags_fs & DN_HAVE_FLOW_MASK) )
        q = fs->rq[0] ;
    else {
        /* first, do the masking, then hash */
        id->dst_port &= fs->flow_mask.dst_port ;
        id->src_port &= fs->flow_mask.src_port ;
        id->proto &= fs->flow_mask.proto ;
        id->flags = 0 ; /* we don't care about this one */
        if (is_v6) {
            APPLY_MASK(&id->dst_ip6, &fs->flow_mask.dst_ip6);
            APPLY_MASK(&id->src_ip6, &fs->flow_mask.src_ip6);
            id->flow_id6 &= fs->flow_mask.flow_id6;

            i = ((id->dst_ip6.__u6_addr.__u6_addr32[0]) & 0xffff)^
                ((id->dst_ip6.__u6_addr.__u6_addr32[1]) & 0xffff)^
                ((id->dst_ip6.__u6_addr.__u6_addr32[2]) & 0xffff)^
                ((id->dst_ip6.__u6_addr.__u6_addr32[3]) & 0xffff)^

                ((id->dst_ip6.__u6_addr.__u6_addr32[0] >> 15) & 0xffff)^
                ((id->dst_ip6.__u6_addr.__u6_addr32[1] >> 15) & 0xffff)^
                ((id->dst_ip6.__u6_addr.__u6_addr32[2] >> 15) & 0xffff)^
                ((id->dst_ip6.__u6_addr.__u6_addr32[3] >> 15) & 0xffff)^

                ((id->src_ip6.__u6_addr.__u6_addr32[0] << 1) & 0xfffff)^
                ((id->src_ip6.__u6_addr.__u6_addr32[1] << 1) & 0xfffff)^
                ((id->src_ip6.__u6_addr.__u6_addr32[2] << 1) & 0xfffff)^
                ((id->src_ip6.__u6_addr.__u6_addr32[3] << 1) & 0xfffff)^

                ((id->src_ip6.__u6_addr.__u6_addr32[0] << 16) & 0xffff)^
                ((id->src_ip6.__u6_addr.__u6_addr32[1] << 16) & 0xffff)^
                ((id->src_ip6.__u6_addr.__u6_addr32[2] << 16) & 0xffff)^
                ((id->src_ip6.__u6_addr.__u6_addr32[3] << 16) & 0xffff)^

                (id->dst_port << 1) ^ (id->src_port) ^
                (id->proto ) ^
                (id->flow_id6);
        } else {
            id->dst_ip &= fs->flow_mask.dst_ip ;
            id->src_ip &= fs->flow_mask.src_ip ;

            i = ( (id->dst_ip) & 0xffff ) ^
                ( (id->dst_ip >> 15) & 0xffff ) ^
                ( (id->src_ip << 1) & 0xffff ) ^
                ( (id->src_ip >> 16 ) & 0xffff ) ^
                (id->dst_port << 1) ^ (id->src_port) ^
                (id->proto );
        }
        i = i % fs->rq_size ;
        /* finally, scan the current list for a match */
        searches++ ;
        for (prev=NULL, q = fs->rq[i] ; q ; ) {
            search_steps++;
            if (is_v6 &&
                    IN6_ARE_ADDR_EQUAL(&id->dst_ip6,&q->id.dst_ip6) &&  
                    IN6_ARE_ADDR_EQUAL(&id->src_ip6,&q->id.src_ip6) &&  
                    id->dst_port == q->id.dst_port &&
                    id->src_port == q->id.src_port &&
                    id->proto == q->id.proto &&
                    id->flags == q->id.flags &&
                    id->flow_id6 == q->id.flow_id6)
                break ; /* found */

            if (!is_v6 && id->dst_ip == q->id.dst_ip &&
                    id->src_ip == q->id.src_ip &&
                    id->dst_port == q->id.dst_port &&
                    id->src_port == q->id.src_port &&
                    id->proto == q->id.proto &&
                    id->flags == q->id.flags)
                break ; /* found */

            /* No match. Check if we can expire the entry */
            if (pipe_expire && q->head == NULL && q->S == q->F+1 ) {
                /* entry is idle and not in any heap, expire it */
                struct dn_flow_queue *old_q = q ;

                if (prev != NULL)
                    prev->next = q = q->next ;
                else
                    fs->rq[i] = q = q->next ;
                fs->rq_elements-- ;
                free(old_q, M_DUMMYNET);
                continue ;
            }
            prev = q ;
            q = q->next ;
        }
        if (q && prev != NULL) { /* found and not in front */
            prev->next = q->next ;
            q->next = fs->rq[i] ;
            fs->rq[i] = q ;
        }
    }
    if (q == NULL) { /* no match, need to allocate a new entry */
        q = create_queue(fs, i);
        if (q != NULL)
        q->id = *id ;
    }
    return q ;
}

static int
red_drops(struct dn_flow_set *fs, struct dn_flow_queue *q, int len)
{
        /*
         * RED algorithm
         *
         * RED calculates the average queue size (avg) using a low-pass filter
         * with an exponential weighted (w_q) moving average:
         *      avg  <-  (1-w_q) * avg + w_q * q_size
         * where q_size is the queue length (measured in bytes or * packets).
         *
         * If q_size == 0, we compute the idle time for the link, and set
         *      avg = (1 - w_q)^(idle/s)
         * where s is the time needed for transmitting a medium-sized packet.
         *
         * Now, if avg < min_th the packet is enqueued.
         * If avg > max_th the packet is dropped. Otherwise, the packet is
         * dropped with probability P function of avg.
         */

        int64_t p_b = 0;

        /* Queue in bytes or packets? */
        u_int q_size = (fs->flags_fs & DN_QSIZE_IS_BYTES) ?
            q->len_bytes : q->len;

        DPRINTF(("\ndummynet: %d q: %2u ", (int)curr_time, q_size));

        /* Average queue size estimation. */
        if (q_size != 0) {
                /* Queue is not empty, avg <- avg + (q_size - avg) * w_q */
                int diff = SCALE(q_size) - q->avg;
                int64_t v = SCALE_MUL((int64_t)diff, (int64_t)fs->w_q);

                q->avg += (int)v;
        } else {
                /*
                 * Queue is empty, find for how long the queue has been
                 * empty and use a lookup table for computing
                 * (1 - * w_q)^(idle_time/s) where s is the time to send a
                 * (small) packet.
                 * XXX check wraps...
                 */
                if (q->avg) {
                        u_int t = ((uint32_t)curr_time - q->q_time) /
                            fs->lookup_step;

                        q->avg = (t < fs->lookup_depth) ?
                            SCALE_MUL(q->avg, fs->w_q_lookup[t]) : 0;
                }
        }
        DPRINTF(("dummynet: avg: %u ", SCALE_VAL(q->avg)));

        /* Should i drop? */
        if (q->avg < fs->min_th) {
                q->count = -1;
                return (0);     /* accept packet */
        }
        if (q->avg >= fs->max_th) {     /* average queue >=  max threshold */
                if (fs->flags_fs & DN_IS_GENTLE_RED) {
                        /*
                         * According to Gentle-RED, if avg is greater than
                         * max_th the packet is dropped with a probability
                         *       p_b = c_3 * avg - c_4
                         * where c_3 = (1 - max_p) / max_th
                         *       c_4 = 1 - 2 * max_p
                         */
                        p_b = SCALE_MUL((int64_t)fs->c_3, (int64_t)q->avg) -
                            fs->c_4;
                } else {
                        q->count = -1;
                        DPRINTF(("dummynet: - drop"));
                        return (1);
                }
        } else if (q->avg > fs->min_th) {
                /*
                 * We compute p_b using the linear dropping function
                 *       p_b = c_1 * avg - c_2
                 * where c_1 = max_p / (max_th - min_th)
                 *       c_2 = max_p * min_th / (max_th - min_th)
                 */
                p_b = SCALE_MUL((int64_t)fs->c_1, (int64_t)q->avg) - fs->c_2;
        }

        if (fs->flags_fs & DN_QSIZE_IS_BYTES)
                p_b = (p_b * len) / fs->max_pkt_size;
        if (++q->count == 0)
                q->random = random() & 0xffff;
        else {
                /*
                 * q->count counts packets arrived since last drop, so a greater
                 * value of q->count means a greater packet drop probability.
                 */
                if (SCALE_MUL(p_b, SCALE((int64_t)q->count)) > q->random) {
                        q->count = 0;
                        DPRINTF(("dummynet: - red drop"));
                        /* After a drop we calculate a new random value. */
                        q->random = random() & 0xffff;
                        return (1);     /* drop */
                }
        }
        /* End of RED algorithm. */

        return (0);     /* accept */
}

static __inline struct dn_flow_set *
locate_flowset(int fs_nr)
{
        struct dn_flow_set *fs;

        SLIST_FOREACH(fs, &flowsethash[HASH(fs_nr)], next)
                if (fs->fs_nr == fs_nr)
                        return (fs);

        return (NULL);
}

static __inline struct dn_pipe *
locate_pipe(int pipe_nr)
{
        struct dn_pipe *pipe;

        SLIST_FOREACH(pipe, &pipehash[HASH(pipe_nr)], next)
                if (pipe->pipe_nr == pipe_nr)
                        return (pipe);

        return (NULL);
}

/*
 * dummynet hook for packets. Below 'pipe' is a pipe or a queue
 * depending on whether WF2Q or fixed bw is used.
 *
 * pipe_nr      pipe or queue the packet is destined for.
 * dir          where shall we send the packet after dummynet.
 * m            the mbuf with the packet
 * ifp          the 'ifp' parameter from the caller.
 *              NULL in ip_input, destination interface in ip_output,
 * rule         matching rule, in case of multiple passes
 */
static int
dummynet_io(struct mbuf **m0, int dir, struct ip_fw_args *fwa)
{
        struct mbuf *m = *m0, *head = NULL, *tail = NULL;
        struct dn_pkt_tag *pkt;
        struct m_tag *mtag;
        struct dn_flow_set *fs = NULL;
        struct dn_pipe *pipe;
        uint64_t len = m->m_pkthdr.len;
        struct dn_flow_queue *q = NULL;
        int is_pipe;
        ipfw_insn *cmd = ACTION_PTR(fwa->rule);

        KASSERT(m->m_nextpkt == NULL,
            ("dummynet_io: mbuf queue passed to dummynet"));

        if (cmd->opcode == O_LOG)
                cmd += F_LEN(cmd);
        if (cmd->opcode == O_ALTQ)
                cmd += F_LEN(cmd);
        if (cmd->opcode == O_TAG)
                cmd += F_LEN(cmd);
        is_pipe = (cmd->opcode == O_PIPE);

        DUMMYNET_LOCK();
        io_pkt++;
        /*
         * This is a dummynet rule, so we expect an O_PIPE or O_QUEUE rule.
         *
         * XXXGL: probably the pipe->fs and fs->pipe logic here
         * below can be simplified.
         */
        if (is_pipe) {
                pipe = locate_pipe(fwa->cookie);
                if (pipe != NULL)
                        fs = &(pipe->fs);
        } else
                fs = locate_flowset(fwa->cookie);

        if (fs == NULL)
                goto dropit;    /* This queue/pipe does not exist! */
        pipe = fs->pipe;
        if (pipe == NULL) {     /* Must be a queue, try find a matching pipe. */
                pipe = locate_pipe(fs->parent_nr);
                if (pipe != NULL)
                        fs->pipe = pipe;
                else {
                        printf("dummynet: no pipe %d for queue %d, drop pkt\n",
                            fs->parent_nr, fs->fs_nr);
                        goto dropit;
                }
        }
        q = find_queue(fs, &(fwa->f_id));
        if (q == NULL)
                goto dropit;            /* Cannot allocate queue. */

        /* Update statistics, then check reasons to drop pkt. */
        q->tot_bytes += len;
        q->tot_pkts++;
        if (fs->plr && random() < fs->plr)
                goto dropit;            /* Random pkt drop. */
        if (fs->flags_fs & DN_QSIZE_IS_BYTES) {
                if (q->len_bytes > fs->qsize)
                        goto dropit;    /* Queue size overflow. */
        } else {
                if (q->len >= fs->qsize)
                        goto dropit;    /* Queue count overflow. */
        }
        if (fs->flags_fs & DN_IS_RED && red_drops(fs, q, len))
                goto dropit;

        /* XXX expensive to zero, see if we can remove it. */
        mtag = m_tag_get(PACKET_TAG_DUMMYNET,
            sizeof(struct dn_pkt_tag), M_NOWAIT | M_ZERO);
        if (mtag == NULL)
                goto dropit;            /* Cannot allocate packet header. */
        m_tag_prepend(m, mtag);         /* Attach to mbuf chain. */

        pkt = (struct dn_pkt_tag *)(mtag + 1);
        /*
         * Ok, i can handle the pkt now...
         * Build and enqueue packet + parameters.
         */
        pkt->rule = fwa->rule;
        pkt->dn_dir = dir;

        pkt->ifp = fwa->oif;

        if (q->head == NULL)
                q->head = m;
        else
                q->tail->m_nextpkt = m;
        q->tail = m;
        q->len++;
        q->len_bytes += len;

        if (q->head != m)               /* Flow was not idle, we are done. */
                goto done;

        if (q->q_time < (uint32_t)curr_time)
                q->numbytes = io_fast ? fs->pipe->bandwidth : 0;
        q->q_time = curr_time;

        /*
         * If we reach this point the flow was previously idle, so we need
         * to schedule it. This involves different actions for fixed-rate or
         * WF2Q queues.
         */
        if (is_pipe) {
                /* Fixed-rate queue: just insert into the ready_heap. */
                dn_key t = 0;

                if (pipe->bandwidth && m->m_pkthdr.len * 8 * hz > q->numbytes)
                        t = SET_TICKS(m, q, pipe);
                q->sched_time = curr_time;
                if (t == 0)             /* Must process it now. */
                        ready_event(q, &head, &tail);
                else
                        heap_insert(&ready_heap, curr_time + t , q);
        } else {
                /*
                 * WF2Q. First, compute start time S: if the flow was
                 * idle (S = F + 1) set S to the virtual time V for the
                 * controlling pipe, and update the sum of weights for the pipe;
                 * otherwise, remove flow from idle_heap and set S to max(F,V).
                 * Second, compute finish time F = S + len / weight.
                 * Third, if pipe was idle, update V = max(S, V).
                 * Fourth, count one more backlogged flow.
                 */
                if (DN_KEY_GT(q->S, q->F)) { /* Means timestamps are invalid. */
                        q->S = pipe->V;
                        pipe->sum += fs->weight; /* Add weight of new queue. */
                } else {
                        heap_extract(&(pipe->idle_heap), q);
                        q->S = MAX64(q->F, pipe->V);
                }
                q->F = q->S + (len << MY_M) / (uint64_t)fs->weight;

                if (pipe->not_eligible_heap.elements == 0 &&
                    pipe->scheduler_heap.elements == 0)
                        pipe->V = MAX64(q->S, pipe->V);
                fs->backlogged++;
                /*
                 * Look at eligibility. A flow is not eligibile if S>V (when
                 * this happens, it means that there is some other flow already
                 * scheduled for the same pipe, so the scheduler_heap cannot be
                 * empty). If the flow is not eligible we just store it in the
                 * not_eligible_heap. Otherwise, we store in the scheduler_heap
                 * and possibly invoke ready_event_wfq() right now if there is
                 * leftover credit.
                 * Note that for all flows in scheduler_heap (SCH), S_i <= V,
                 * and for all flows in not_eligible_heap (NEH), S_i > V.
                 * So when we need to compute max(V, min(S_i)) forall i in
                 * SCH+NEH, we only need to look into NEH.
                 */
                if (DN_KEY_GT(q->S, pipe->V)) {         /* Not eligible. */
                        if (pipe->scheduler_heap.elements == 0)
                                printf("dummynet: ++ ouch! not eligible but empty scheduler!\n");
                        heap_insert(&(pipe->not_eligible_heap), q->S, q);
                } else {
                        heap_insert(&(pipe->scheduler_heap), q->F, q);
                        if (pipe->numbytes >= 0) {       /* Pipe is idle. */
                                if (pipe->scheduler_heap.elements != 1)
                                        printf("dummynet: OUCH! pipe should have been idle!\n");
                                DPRINTF(("dummynet: waking up pipe %d at %d\n",
                                    pipe->pipe_nr, (int)(q->F >> MY_M)));
                                pipe->sched_time = curr_time;
                                ready_event_wfq(pipe, &head, &tail);
                        }
                }
        }
done:
        if (head == m && dir != DN_TO_IFB_FWD && dir != DN_TO_ETH_DEMUX &&
            dir != DN_TO_ETH_OUT) {     /* Fast io. */
                io_pkt_fast++;
                if (m->m_nextpkt != NULL)
                        printf("dummynet: fast io: pkt chain detected!\n");
                head = m->m_nextpkt = NULL;
        } else
                *m0 = NULL;             /* Normal io. */

        DUMMYNET_UNLOCK();
        if (head != NULL)
                dummynet_send(head);
        return (0);

dropit:
        io_pkt_drop++;
        if (q)
                q->drops++;
        DUMMYNET_UNLOCK();
        m_freem(m);
        *m0 = NULL;
        return ((fs && (fs->flags_fs & DN_NOERROR)) ? 0 : ENOBUFS);
}

/*
 * Below, the rt_unref is only needed when (pkt->dn_dir == DN_TO_IP_OUT)
 * Doing this would probably save us the initial bzero of dn_pkt
 */
#define DN_FREE_PKT(_m) do {                            \
        m_freem(_m);                                    \
} while (0)

/*
 * Dispose all packets and flow_queues on a flow_set.
 * If all=1, also remove red lookup table and other storage,
 * including the descriptor itself.
 * For the one in dn_pipe MUST also cleanup ready_heap...
 */
static void
purge_flow_set(struct dn_flow_set *fs, int all)
{
        struct dn_flow_queue *q, *qn;
        int i;

        DUMMYNET_LOCK_ASSERT();

        for (i = 0; i <= fs->rq_size; i++) {
                for (q = fs->rq[i]; q != NULL; q = qn) {
                        struct mbuf *m, *mnext;

                        mnext = q->head;
                        while ((m = mnext) != NULL) {
                                mnext = m->m_nextpkt;
                                DN_FREE_PKT(m);
                        }
                        qn = q->next;
                        free(q, M_DUMMYNET);
                }
                fs->rq[i] = NULL;
        }

        fs->rq_elements = 0;
        if (all) {
                /* RED - free lookup table. */
                if (fs->w_q_lookup != NULL)
                        free(fs->w_q_lookup, M_DUMMYNET);
                if (fs->rq != NULL)
                        free(fs->rq, M_DUMMYNET);
                /* If this fs is not part of a pipe, free it. */
                if (fs->pipe == NULL || fs != &(fs->pipe->fs))
                        free(fs, M_DUMMYNET);
        }
}

/*
 * Dispose all packets queued on a pipe (not a flow_set).
 * Also free all resources associated to a pipe, which is about
 * to be deleted.
 */
static void
purge_pipe(struct dn_pipe *pipe)
{
    struct mbuf *m, *mnext;

    purge_flow_set( &(pipe->fs), 1 );

    mnext = pipe->head;
    while ((m = mnext) != NULL) {
        mnext = m->m_nextpkt;
        DN_FREE_PKT(m);
    }

    heap_free( &(pipe->scheduler_heap) );
    heap_free( &(pipe->not_eligible_heap) );
    heap_free( &(pipe->idle_heap) );
}

/*
 * Delete all pipes and heaps returning memory. Must also
 * remove references from all ipfw rules to all pipes.
 */
static void
dummynet_flush(void)
{
        struct dn_pipe *pipe, *pipe1;
        struct dn_flow_set *fs, *fs1;
        int i;

        DUMMYNET_LOCK();
        /* Free heaps so we don't have unwanted events. */
        heap_free(&ready_heap);
        heap_free(&wfq_ready_heap);
        heap_free(&extract_heap);

        /*
         * Now purge all queued pkts and delete all pipes.
         *
         * XXXGL: can we merge the for(;;) cycles into one or not?
         */
        for (i = 0; i < HASHSIZE; i++)
                SLIST_FOREACH_SAFE(fs, &flowsethash[i], next, fs1) {
                        SLIST_REMOVE(&flowsethash[i], fs, dn_flow_set, next);
                        purge_flow_set(fs, 1);
                }
        for (i = 0; i < HASHSIZE; i++)
                SLIST_FOREACH_SAFE(pipe, &pipehash[i], next, pipe1) {
                        SLIST_REMOVE(&pipehash[i], pipe, dn_pipe, next);
                        purge_pipe(pipe);
                        free(pipe, M_DUMMYNET);
                }
        DUMMYNET_UNLOCK();
}

extern struct ip_fw *ip_fw_default_rule ;
static void
dn_rule_delete_fs(struct dn_flow_set *fs, void *r)
{
    int i ;
    struct dn_flow_queue *q ;
    struct mbuf *m ;

    for (i = 0 ; i <= fs->rq_size ; i++) /* last one is ovflow */
        for (q = fs->rq[i] ; q ; q = q->next )
            for (m = q->head ; m ; m = m->m_nextpkt ) {
                struct dn_pkt_tag *pkt = dn_tag_get(m) ;
                if (pkt->rule == r)
                    pkt->rule = ip_fw_default_rule ;
            }
}
/*
 * when a firewall rule is deleted, scan all queues and remove the flow-id
 * from packets matching this rule.
 */
void
dn_rule_delete(void *r)
{
    struct dn_pipe *pipe;
    struct dn_flow_set *fs;
    struct dn_pkt_tag *pkt;
    struct mbuf *m;
    int i;

    DUMMYNET_LOCK();
    /*
     * If the rule references a queue (dn_flow_set), then scan
     * the flow set, otherwise scan pipes. Should do either, but doing
     * both does not harm.
     */
    for (i = 0; i < HASHSIZE; i++)
        SLIST_FOREACH(fs, &flowsethash[i], next)
                dn_rule_delete_fs(fs, r);

    for (i = 0; i < HASHSIZE; i++)
        SLIST_FOREACH(pipe, &pipehash[i], next) {
                fs = &(pipe->fs);
                dn_rule_delete_fs(fs, r);
                for (m = pipe->head ; m ; m = m->m_nextpkt ) {
                        pkt = dn_tag_get(m);
                        if (pkt->rule == r)
                                pkt->rule = ip_fw_default_rule;
                }
        }
    DUMMYNET_UNLOCK();
}

/*
 * setup RED parameters
 */
static int
config_red(struct dn_flow_set *p, struct dn_flow_set *x)
{
        int i;

        x->w_q = p->w_q;
        x->min_th = SCALE(p->min_th);
        x->max_th = SCALE(p->max_th);
        x->max_p = p->max_p;

        x->c_1 = p->max_p / (p->max_th - p->min_th);
        x->c_2 = SCALE_MUL(x->c_1, SCALE(p->min_th));

        if (x->flags_fs & DN_IS_GENTLE_RED) {
                x->c_3 = (SCALE(1) - p->max_p) / p->max_th;
                x->c_4 = SCALE(1) - 2 * p->max_p;
        }

        /* If the lookup table already exist, free and create it again. */
        if (x->w_q_lookup) {
                free(x->w_q_lookup, M_DUMMYNET);
                x->w_q_lookup = NULL;
        }
        if (red_lookup_depth == 0) {
                printf("\ndummynet: net.inet.ip.dummynet.red_lookup_depth"
                    "must be > 0\n");
                free(x, M_DUMMYNET);
                return (EINVAL);
        }
        x->lookup_depth = red_lookup_depth;
        x->w_q_lookup = (u_int *)malloc(x->lookup_depth * sizeof(int),
            M_DUMMYNET, M_NOWAIT);
        if (x->w_q_lookup == NULL) {
                printf("dummynet: sorry, cannot allocate red lookup table\n");
                free(x, M_DUMMYNET);
                return(ENOSPC);
        }

        /* Fill the lookup table with (1 - w_q)^x */
        x->lookup_step = p->lookup_step;
        x->lookup_weight = p->lookup_weight;
        x->w_q_lookup[0] = SCALE(1) - x->w_q;

        for (i = 1; i < x->lookup_depth; i++)
                x->w_q_lookup[i] =
                    SCALE_MUL(x->w_q_lookup[i - 1], x->lookup_weight);

        if (red_avg_pkt_size < 1)
                red_avg_pkt_size = 512;
        x->avg_pkt_size = red_avg_pkt_size;
        if (red_max_pkt_size < 1)
                red_max_pkt_size = 1500;
        x->max_pkt_size = red_max_pkt_size;
        return (0);
}

static int
alloc_hash(struct dn_flow_set *x, struct dn_flow_set *pfs)
{
    if (x->flags_fs & DN_HAVE_FLOW_MASK) {     /* allocate some slots */
        int l = pfs->rq_size;

        if (l == 0)
            l = dn_hash_size;
        if (l < 4)
            l = 4;
        else if (l > DN_MAX_HASH_SIZE)
            l = DN_MAX_HASH_SIZE;
        x->rq_size = l;
    } else                  /* one is enough for null mask */
        x->rq_size = 1;
    x->rq = malloc((1 + x->rq_size) * sizeof(struct dn_flow_queue *),
            M_DUMMYNET, M_NOWAIT | M_ZERO);
    if (x->rq == NULL) {
        printf("dummynet: sorry, cannot allocate queue\n");
        return (ENOMEM);
    }
    x->rq_elements = 0;
    return 0 ;
}

static void
set_fs_parms(struct dn_flow_set *x, struct dn_flow_set *src)
{
        x->flags_fs = src->flags_fs;
        x->qsize = src->qsize;
        x->plr = src->plr;
        x->flow_mask = src->flow_mask;
        if (x->flags_fs & DN_QSIZE_IS_BYTES) {
                if (x->qsize > pipe_byte_limit)
                        x->qsize = 1024 * 1024;
        } else {
                if (x->qsize == 0)
                        x->qsize = 50;
                if (x->qsize > pipe_slot_limit)
                        x->qsize = 50;
        }
        /* Configuring RED. */
        if (x->flags_fs & DN_IS_RED)
                config_red(src, x);     /* XXX should check errors */
}

/*
 * Setup pipe or queue parameters.
 */
static int
config_pipe(struct dn_pipe *p)
{
        struct dn_flow_set *pfs = &(p->fs);
        struct dn_flow_queue *q;
        int i, error;

        /*
         * The config program passes parameters as follows:
         * bw = bits/second (0 means no limits),
         * delay = ms, must be translated into ticks.
         * qsize = slots/bytes
         */
        p->delay = (p->delay * hz) / 1000;
        /* We need either a pipe number or a flow_set number. */
        if (p->pipe_nr == 0 && pfs->fs_nr == 0)
                return (EINVAL);
        if (p->pipe_nr != 0 && pfs->fs_nr != 0)
                return (EINVAL);
        if (p->pipe_nr != 0) {                  /* this is a pipe */
                struct dn_pipe *pipe;

                DUMMYNET_LOCK();
                pipe = locate_pipe(p->pipe_nr); /* locate pipe */

                if (pipe == NULL) {             /* new pipe */
                        pipe = malloc(sizeof(struct dn_pipe), M_DUMMYNET,
                            M_NOWAIT | M_ZERO);
                        if (pipe == NULL) {
                                DUMMYNET_UNLOCK();
                                printf("dummynet: no memory for new pipe\n");
                                return (ENOMEM);
                        }
                        pipe->pipe_nr = p->pipe_nr;
                        pipe->fs.pipe = pipe;
                        /*
                         * idle_heap is the only one from which
                         * we extract from the middle.
                         */
                        pipe->idle_heap.size = pipe->idle_heap.elements = 0;
                        pipe->idle_heap.offset =
                            offsetof(struct dn_flow_queue, heap_pos);
                } else
                        /* Flush accumulated credit for all queues. */
                        for (i = 0; i <= pipe->fs.rq_size; i++)
                                for (q = pipe->fs.rq[i]; q; q = q->next)
                                        q->numbytes = io_fast ? p->bandwidth : 0;

                pipe->bandwidth = p->bandwidth;
                pipe->numbytes = 0;             /* just in case... */
                bcopy(p->if_name, pipe->if_name, sizeof(p->if_name));
                pipe->ifp = NULL;               /* reset interface ptr */
                pipe->delay = p->delay;
                set_fs_parms(&(pipe->fs), pfs);

                if (pipe->fs.rq == NULL) {      /* a new pipe */
                        error = alloc_hash(&(pipe->fs), pfs);
                        if (error) {
                                DUMMYNET_UNLOCK();
                                free(pipe, M_DUMMYNET);
                                return (error);
                        }
                        SLIST_INSERT_HEAD(&pipehash[HASH(pipe->pipe_nr)],
                            pipe, next);
                }
                DUMMYNET_UNLOCK();
        } else {                                /* config queue */
                struct dn_flow_set *fs;

                DUMMYNET_LOCK();
                fs = locate_flowset(pfs->fs_nr); /* locate flow_set */

                if (fs == NULL) {               /* new */
                        if (pfs->parent_nr == 0) { /* need link to a pipe */
                                DUMMYNET_UNLOCK();
                                return (EINVAL);
                        }
                        fs = malloc(sizeof(struct dn_flow_set), M_DUMMYNET,
                            M_NOWAIT | M_ZERO);
                        if (fs == NULL) {
                                DUMMYNET_UNLOCK();
                                printf(
                                    "dummynet: no memory for new flow_set\n");
                                return (ENOMEM);
                        }
                        fs->fs_nr = pfs->fs_nr;
                        fs->parent_nr = pfs->parent_nr;
                        fs->weight = pfs->weight;
                        if (fs->weight == 0)
                                fs->weight = 1;
                        else if (fs->weight > 100)
                                fs->weight = 100;
                } else {
                        /*
                         * Change parent pipe not allowed;
                         * must delete and recreate.
                         */
                        if (pfs->parent_nr != 0 &&
                            fs->parent_nr != pfs->parent_nr) {
                                DUMMYNET_UNLOCK();
                                return (EINVAL);
                        }
                }

                set_fs_parms(fs, pfs);

                if (fs->rq == NULL) {           /* a new flow_set */
                        error = alloc_hash(fs, pfs);
                        if (error) {
                                DUMMYNET_UNLOCK();
                                free(fs, M_DUMMYNET);
                                return (error);
                        }
                        SLIST_INSERT_HEAD(&flowsethash[HASH(fs->fs_nr)],
                            fs, next);
                }
                DUMMYNET_UNLOCK();
        }
        return (0);
}

/*
 * Helper function to remove from a heap queues which are linked to
 * a flow_set about to be deleted.
 */
static void
fs_remove_from_heap(struct dn_heap *h, struct dn_flow_set *fs)
{
    int i = 0, found = 0 ;
    for (; i < h->elements ;)
        if ( ((struct dn_flow_queue *)h->p[i].object)->fs == fs) {
            h->elements-- ;
            h->p[i] = h->p[h->elements] ;
            found++ ;
        } else
            i++ ;
    if (found)
        heapify(h);
}

/*
 * helper function to remove a pipe from a heap (can be there at most once)
 */
static void
pipe_remove_from_heap(struct dn_heap *h, struct dn_pipe *p)
{
    if (h->elements > 0) {
        int i = 0 ;
        for (i=0; i < h->elements ; i++ ) {
            if (h->p[i].object == p) { /* found it */
                h->elements-- ;
                h->p[i] = h->p[h->elements] ;
                heapify(h);
                break ;
            }
        }
    }
}

/*
 * drain all queues. Called in case of severe mbuf shortage.
 */
void
dummynet_drain(void)
{
    struct dn_flow_set *fs;
    struct dn_pipe *pipe;
    struct mbuf *m, *mnext;
    int i;

    DUMMYNET_LOCK_ASSERT();

    heap_free(&ready_heap);
    heap_free(&wfq_ready_heap);
    heap_free(&extract_heap);
    /* remove all references to this pipe from flow_sets */
    for (i = 0; i < HASHSIZE; i++)
        SLIST_FOREACH(fs, &flowsethash[i], next)
                purge_flow_set(fs, 0);

    for (i = 0; i < HASHSIZE; i++) {
        SLIST_FOREACH(pipe, &pipehash[i], next) {
                purge_flow_set(&(pipe->fs), 0);

                mnext = pipe->head;
                while ((m = mnext) != NULL) {
                        mnext = m->m_nextpkt;
                        DN_FREE_PKT(m);
                }
                pipe->head = pipe->tail = NULL;
        }
    }
}

/*
 * Fully delete a pipe or a queue, cleaning up associated info.
 */
static int
delete_pipe(struct dn_pipe *p)
{

    if (p->pipe_nr == 0 && p->fs.fs_nr == 0)
        return EINVAL ;
    if (p->pipe_nr != 0 && p->fs.fs_nr != 0)
        return EINVAL ;
    if (p->pipe_nr != 0) { /* this is an old-style pipe */
        struct dn_pipe *pipe;
        struct dn_flow_set *fs;
        int i;

        DUMMYNET_LOCK();
        pipe = locate_pipe(p->pipe_nr); /* locate pipe */

        if (pipe == NULL) {
            DUMMYNET_UNLOCK();
            return (ENOENT);    /* not found */
        }

        /* Unlink from list of pipes. */
        SLIST_REMOVE(&pipehash[HASH(pipe->pipe_nr)], pipe, dn_pipe, next);

        /* Remove all references to this pipe from flow_sets. */
        for (i = 0; i < HASHSIZE; i++)
            SLIST_FOREACH(fs, &flowsethash[i], next)
                if (fs->pipe == pipe) {
                        printf("dummynet: ++ ref to pipe %d from fs %d\n",
                            p->pipe_nr, fs->fs_nr);
                        fs->pipe = NULL ;
                        purge_flow_set(fs, 0);
                }
        fs_remove_from_heap(&ready_heap, &(pipe->fs));
        purge_pipe(pipe); /* remove all data associated to this pipe */
        /* remove reference to here from extract_heap and wfq_ready_heap */
        pipe_remove_from_heap(&extract_heap, pipe);
        pipe_remove_from_heap(&wfq_ready_heap, pipe);
        DUMMYNET_UNLOCK();

        free(pipe, M_DUMMYNET);
    } else { /* this is a WF2Q queue (dn_flow_set) */
        struct dn_flow_set *fs;

        DUMMYNET_LOCK();
        fs = locate_flowset(p->fs.fs_nr); /* locate set */

        if (fs == NULL) {
            DUMMYNET_UNLOCK();
            return (ENOENT); /* not found */
        }

        /* Unlink from list of flowsets. */
        SLIST_REMOVE( &flowsethash[HASH(fs->fs_nr)], fs, dn_flow_set, next);

        if (fs->pipe != NULL) {
            /* Update total weight on parent pipe and cleanup parent heaps. */
            fs->pipe->sum -= fs->weight * fs->backlogged ;
            fs_remove_from_heap(&(fs->pipe->not_eligible_heap), fs);
            fs_remove_from_heap(&(fs->pipe->scheduler_heap), fs);
#if 1   /* XXX should i remove from idle_heap as well ? */
            fs_remove_from_heap(&(fs->pipe->idle_heap), fs);
#endif
        }
        purge_flow_set(fs, 1);
        DUMMYNET_UNLOCK();
    }
    return 0 ;
}

/*
 * helper function used to copy data from kernel in DUMMYNET_GET
 */
static char *
dn_copy_set(struct dn_flow_set *set, char *bp)
{
    int i, copied = 0 ;
    struct dn_flow_queue *q, *qp = (struct dn_flow_queue *)bp;

    DUMMYNET_LOCK_ASSERT();

    for (i = 0 ; i <= set->rq_size ; i++)
        for (q = set->rq[i] ; q ; q = q->next, qp++ ) {
            if (q->hash_slot != i)
                printf("dummynet: ++ at %d: wrong slot (have %d, "
                    "should be %d)\n", copied, q->hash_slot, i);
            if (q->fs != set)
                printf("dummynet: ++ at %d: wrong fs ptr (have %p, should be %p)\n",
                        i, q->fs, set);
            copied++ ;
            bcopy(q, qp, sizeof( *q ) );
            /* cleanup pointers */
            qp->next = NULL ;
            qp->head = qp->tail = NULL ;
            qp->fs = NULL ;
        }
    if (copied != set->rq_elements)
        printf("dummynet: ++ wrong count, have %d should be %d\n",
            copied, set->rq_elements);
    return (char *)qp ;
}

static size_t
dn_calc_size(void)
{
    struct dn_flow_set *fs;
    struct dn_pipe *pipe;
    size_t size = 0;
    int i;

    DUMMYNET_LOCK_ASSERT();
    /*
     * Compute size of data structures: list of pipes and flow_sets.
     */
    for (i = 0; i < HASHSIZE; i++) {
        SLIST_FOREACH(pipe, &pipehash[i], next)
                size += sizeof(*pipe) +
                    pipe->fs.rq_elements * sizeof(struct dn_flow_queue);
        SLIST_FOREACH(fs, &flowsethash[i], next)
                size += sizeof (*fs) +
                    fs->rq_elements * sizeof(struct dn_flow_queue);
    }
    return size;
}

static int
dummynet_get(struct sockopt *sopt)
{
    char *buf, *bp ; /* bp is the "copy-pointer" */
    size_t size ;
    struct dn_flow_set *fs;
    struct dn_pipe *pipe;
    int error=0, i ;

    /* XXX lock held too long */
    DUMMYNET_LOCK();
    /*
     * XXX: Ugly, but we need to allocate memory with M_WAITOK flag and we
     *      cannot use this flag while holding a mutex.
     */
    for (i = 0; i < 10; i++) {
        size = dn_calc_size();
        DUMMYNET_UNLOCK();
        buf = malloc(size, M_TEMP, M_WAITOK);
        DUMMYNET_LOCK();
        if (size == dn_calc_size())
                break;
        free(buf, M_TEMP);
        buf = NULL;
    }
    if (buf == NULL) {
        DUMMYNET_UNLOCK();
        return ENOBUFS ;
    }
    bp = buf;
    for (i = 0; i < HASHSIZE; i++)
        SLIST_FOREACH(pipe, &pipehash[i], next) {
                struct dn_pipe *pipe_bp = (struct dn_pipe *)bp;

                /*
                 * Copy pipe descriptor into *bp, convert delay back to ms,
                 * then copy the flow_set descriptor(s) one at a time.
                 * After each flow_set, copy the queue descriptor it owns.
                 */
                bcopy(pipe, bp, sizeof(*pipe));
                pipe_bp->delay = (pipe_bp->delay * 1000) / hz;
                /*
                 * XXX the following is a hack based on ->next being the
                 * first field in dn_pipe and dn_flow_set. The correct
                 * solution would be to move the dn_flow_set to the beginning
                 * of struct dn_pipe.
                 */
                pipe_bp->next.sle_next = (struct dn_pipe *)DN_IS_PIPE;
                /* Clean pointers. */
                pipe_bp->head = pipe_bp->tail = NULL;
                pipe_bp->fs.next.sle_next = NULL;
                pipe_bp->fs.pipe = NULL;
                pipe_bp->fs.rq = NULL;

                bp += sizeof(*pipe) ;
                bp = dn_copy_set(&(pipe->fs), bp);
        }

    for (i = 0; i < HASHSIZE; i++)
        SLIST_FOREACH(fs, &flowsethash[i], next) {
                struct dn_flow_set *fs_bp = (struct dn_flow_set *)bp;

                bcopy(fs, bp, sizeof(*fs));
                /* XXX same hack as above */
                fs_bp->next.sle_next = (struct dn_flow_set *)DN_IS_QUEUE;
                fs_bp->pipe = NULL;
                fs_bp->rq = NULL;
                bp += sizeof(*fs);
                bp = dn_copy_set(fs, bp);
        }

    DUMMYNET_UNLOCK();

    error = sooptcopyout(sopt, buf, size);
    free(buf, M_TEMP);
    return error ;
}

/*
 * Handler for the various dummynet socket options (get, flush, config, del)
 */
static int
ip_dn_ctl(struct sockopt *sopt)
{
    int error = 0 ;
    struct dn_pipe *p, tmp_pipe;

    error = priv_check(sopt->sopt_td, PRIV_NETINET_DUMMYNET);
    if (error)
        return (error);

    /* Disallow sets in really-really secure mode. */
    if (sopt->sopt_dir == SOPT_SET) {
#if __FreeBSD_version >= 500034
        error =  securelevel_ge(sopt->sopt_td->td_ucred, 3);
        if (error)
            return (error);
#else
        if (securelevel >= 3)
            return (EPERM);
#endif
    }

    switch (sopt->sopt_name) {
    default :
        printf("dummynet: -- unknown option %d", sopt->sopt_name);
        return EINVAL ;

    case IP_DUMMYNET_GET :
        error = dummynet_get(sopt);
        break ;

    case IP_DUMMYNET_FLUSH :
        dummynet_flush() ;
        break ;

    case IP_DUMMYNET_CONFIGURE :
        p = &tmp_pipe ;
        error = sooptcopyin(sopt, p, sizeof *p, sizeof *p);
        if (error)
            break ;
        error = config_pipe(p);
        break ;

    case IP_DUMMYNET_DEL :      /* remove a pipe or queue */
        p = &tmp_pipe ;
        error = sooptcopyin(sopt, p, sizeof *p, sizeof *p);
        if (error)
            break ;

        error = delete_pipe(p);
        break ;
    }
    return error ;
}

static void
ip_dn_init(void)
{
        int i;

        if (bootverbose)
                printf("DUMMYNET with IPv6 initialized (040826)\n");

        DUMMYNET_LOCK_INIT();

        for (i = 0; i < HASHSIZE; i++) {
                SLIST_INIT(&pipehash[i]);
                SLIST_INIT(&flowsethash[i]);
        }
        ready_heap.size = ready_heap.elements = 0;
        ready_heap.offset = 0;

        wfq_ready_heap.size = wfq_ready_heap.elements = 0;
        wfq_ready_heap.offset = 0;

        extract_heap.size = extract_heap.elements = 0;
        extract_heap.offset = 0;

        ip_dn_ctl_ptr = ip_dn_ctl;
        ip_dn_io_ptr = dummynet_io;
        ip_dn_ruledel_ptr = dn_rule_delete;

        TASK_INIT(&dn_task, 0, dummynet_task, NULL);
        dn_tq = taskqueue_create_fast("dummynet", M_NOWAIT,
            taskqueue_thread_enqueue, &dn_tq);
        taskqueue_start_threads(&dn_tq, 1, PI_NET, "dummynet");

        callout_init(&dn_timeout, CALLOUT_MPSAFE);
        callout_reset(&dn_timeout, 1, dummynet, NULL);

        /* Initialize curr_time adjustment mechanics. */
        getmicrouptime(&prev_t);
}

#ifdef KLD_MODULE
static void
ip_dn_destroy(void)
{
        ip_dn_ctl_ptr = NULL;
        ip_dn_io_ptr = NULL;
        ip_dn_ruledel_ptr = NULL;

        DUMMYNET_LOCK();
        callout_stop(&dn_timeout);
        DUMMYNET_UNLOCK();
        taskqueue_drain(dn_tq, &dn_task);
        taskqueue_free(dn_tq);

        dummynet_flush();

        DUMMYNET_LOCK_DESTROY();
}
#endif /* KLD_MODULE */

static int
dummynet_modevent(module_t mod, int type, void *data)
{

        switch (type) {
        case MOD_LOAD:
                if (DUMMYNET_LOADED) {
                    printf("DUMMYNET already loaded\n");
                    return EEXIST ;
                }
                ip_dn_init();
                break;

        case MOD_UNLOAD:
#if !defined(KLD_MODULE)
                printf("dummynet statically compiled, cannot unload\n");
                return EINVAL ;
#else
                ip_dn_destroy();
#endif
                break ;
        default:
                return EOPNOTSUPP;
                break ;
        }
        return 0 ;
}

static moduledata_t dummynet_mod = {
        "dummynet",
        dummynet_modevent,
        NULL
};
DECLARE_MODULE(dummynet, dummynet_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
MODULE_DEPEND(dummynet, ipfw, 2, 2, 2);
MODULE_VERSION(dummynet, 1);