xnu-1456.1.26.tar.gz

[apple/xnu.git] / bsd / netinet / ip_dummynet.c

/*
 * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 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.
 *
 * $FreeBSD: src/sys/netinet/ip_dummynet.c,v 1.84 2004/08/25 09:31:30 pjd Exp $
 */

#define DUMMYNET_DEBUG

/*
 * 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:
 *
 * 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/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/queue.h>                  /* XXX */
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/time.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/route.h>
#include <net/kpi_protocol.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_dummynet.h>
#include <netinet/ip_var.h>

#if BRIDGE
#include <netinet/if_ether.h> /* for struct arpcom */
#include <net/bridge.h>
#endif

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

/* this is for the timer that fires to call dummynet() - we only enable the timer when
        there are packets to process, otherwise it's disabled */
static int timer_enabled = 0;   

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

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

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 */

/*
 * 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.
 *
 */
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);

/* 
 * Packets are retrieved from queues in Dummynet in chains instead of
 * packet-by-packet.  The entire list of packets is first dequeued and
 * sent out by the following function.
 */
static void dummynet_send(struct mbuf *m);

/* Flag to signify the existance of a dequeued packet chain */
static int serialize = 0;

#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 */


#ifdef SYSCTL_NODE
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");
SYSCTL_QUAD(_net_inet_ip_dummynet, OID_AUTO, curr_time,
            CTLFLAG_RD, &curr_time, "Current tick");
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_INT(_net_inet_ip_dummynet, OID_AUTO, searches,
            CTLFLAG_RD, &searches, 0, "Number of queue searches");
SYSCTL_INT(_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");
#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

/* contrary to the comment above random(), it does not actually
 * return a value [0, 2^31 - 1], which breaks plr amongst other
 * things. Masking it should work even if the behavior of
 * the function is fixed.
 */
#define MY_RANDOM (random() & 0x7FFFFFFF)

/* dummynet lock */
static lck_grp_t         *dn_mutex_grp;
static lck_grp_attr_t    *dn_mutex_grp_attr;
static lck_attr_t        *dn_mutex_attr;
static lck_mtx_t         *dn_mutex;

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);
void dummynet_drain(void);
static ip_dn_io_t dummynet_io;
static void dn_rule_delete(void *);

int if_tx_rdy(struct ifnet *ifp);

static void cp_flow_set_to_64_user(struct dn_flow_set *set, struct dn_flow_set_64 *fs_bp);
static void cp_queue_to_64_user( struct dn_flow_queue *q, struct dn_flow_queue_64 *qp);
static char *cp_pipe_to_64_user(struct dn_pipe *p, struct dn_pipe_64 *pipe_bp);
static char* dn_copy_set_64(struct dn_flow_set *set, char *bp);
static int cp_pipe_from_user_64( struct sockopt *sopt, struct dn_pipe *p );

static void cp_flow_set_to_32_user(struct dn_flow_set *set, struct dn_flow_set_32 *fs_bp);
static void cp_queue_to_32_user( struct dn_flow_queue *q, struct dn_flow_queue_32 *qp);
static char *cp_pipe_to_32_user(struct dn_pipe *p, struct dn_pipe_32 *pipe_bp);
static char* dn_copy_set_32(struct dn_flow_set *set, char *bp);
static int cp_pipe_from_user_32( struct sockopt *sopt, struct dn_pipe *p );


/*
 * 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


int cp_pipe_from_user_32( struct sockopt *sopt, struct dn_pipe *p )
{
        struct dn_pipe_32 user_pipe_32;
        int error=0;
        
        error = sooptcopyin(sopt, &user_pipe_32, sizeof(struct dn_pipe_32), sizeof(struct dn_pipe_32));
        if ( !error ){
                p->pipe_nr = user_pipe_32.pipe_nr;
                p->bandwidth = user_pipe_32.bandwidth;
                p->delay = user_pipe_32.delay;
                p->V = user_pipe_32.V;
                p->sum = user_pipe_32.sum;
                p->numbytes = user_pipe_32.numbytes;
                p->sched_time = user_pipe_32.sched_time;
                bcopy( user_pipe_32.if_name, p->if_name, IFNAMSIZ);
                p->ready = user_pipe_32.ready;
                
                p->fs.fs_nr = user_pipe_32.fs.fs_nr;
                p->fs.flags_fs = user_pipe_32.fs.flags_fs;
                p->fs.parent_nr = user_pipe_32.fs.parent_nr;
                p->fs.weight = user_pipe_32.fs.weight;
                p->fs.qsize = user_pipe_32.fs.qsize;
                p->fs.plr = user_pipe_32.fs.plr;
                p->fs.flow_mask = user_pipe_32.fs.flow_mask;
                p->fs.rq_size = user_pipe_32.fs.rq_size;
                p->fs.rq_elements = user_pipe_32.fs.rq_elements;
                p->fs.last_expired = user_pipe_32.fs.last_expired;
                p->fs.backlogged = user_pipe_32.fs.backlogged;
                p->fs.w_q = user_pipe_32.fs.w_q;
                p->fs.max_th = user_pipe_32.fs.max_th;
                p->fs.min_th = user_pipe_32.fs.min_th;
                p->fs.max_p = user_pipe_32.fs.max_p;
                p->fs.c_1 = user_pipe_32.fs.c_1;
                p->fs.c_2 = user_pipe_32.fs.c_2;
                p->fs.c_3 = user_pipe_32.fs.c_3;
                p->fs.c_4 = user_pipe_32.fs.c_4;
                p->fs.lookup_depth = user_pipe_32.fs.lookup_depth;
                p->fs.lookup_step = user_pipe_32.fs.lookup_step;
                p->fs.lookup_weight = user_pipe_32.fs.lookup_weight;
                p->fs.avg_pkt_size = user_pipe_32.fs.avg_pkt_size;
                p->fs.max_pkt_size = user_pipe_32.fs.max_pkt_size;
        }
        return error;
}


int cp_pipe_from_user_64( struct sockopt *sopt, struct dn_pipe *p )
{
        struct dn_pipe_64 user_pipe_64;
        int error=0;
        
        error = sooptcopyin(sopt, &user_pipe_64, sizeof(struct dn_pipe_64), sizeof(struct dn_pipe_64));
        if ( !error ){
                p->pipe_nr = user_pipe_64.pipe_nr;
                p->bandwidth = user_pipe_64.bandwidth;
                p->delay = user_pipe_64.delay;
                p->V = user_pipe_64.V;
                p->sum = user_pipe_64.sum;
                p->numbytes = user_pipe_64.numbytes;
                p->sched_time = user_pipe_64.sched_time;
                bcopy( user_pipe_64.if_name, p->if_name, IFNAMSIZ);
                p->ready = user_pipe_64.ready;
                
                p->fs.fs_nr = user_pipe_64.fs.fs_nr;
                p->fs.flags_fs = user_pipe_64.fs.flags_fs;
                p->fs.parent_nr = user_pipe_64.fs.parent_nr;
                p->fs.weight = user_pipe_64.fs.weight;
                p->fs.qsize = user_pipe_64.fs.qsize;
                p->fs.plr = user_pipe_64.fs.plr;
                p->fs.flow_mask = user_pipe_64.fs.flow_mask;
                p->fs.rq_size = user_pipe_64.fs.rq_size;
                p->fs.rq_elements = user_pipe_64.fs.rq_elements;
                p->fs.last_expired = user_pipe_64.fs.last_expired;
                p->fs.backlogged = user_pipe_64.fs.backlogged;
                p->fs.w_q = user_pipe_64.fs.w_q;
                p->fs.max_th = user_pipe_64.fs.max_th;
                p->fs.min_th = user_pipe_64.fs.min_th;
                p->fs.max_p = user_pipe_64.fs.max_p;
                p->fs.c_1 = user_pipe_64.fs.c_1;
                p->fs.c_2 = user_pipe_64.fs.c_2;
                p->fs.c_3 = user_pipe_64.fs.c_3;
                p->fs.c_4 = user_pipe_64.fs.c_4;
                p->fs.lookup_depth = user_pipe_64.fs.lookup_depth;
                p->fs.lookup_step = user_pipe_64.fs.lookup_step;
                p->fs.lookup_weight = user_pipe_64.fs.lookup_weight;
                p->fs.avg_pkt_size = user_pipe_64.fs.avg_pkt_size;
                p->fs.max_pkt_size = user_pipe_64.fs.max_pkt_size;
        }
        return error;
}

static void
cp_flow_set_to_32_user(struct dn_flow_set *set, struct dn_flow_set_32 *fs_bp)
{
        fs_bp->fs_nr = set->fs_nr;
        fs_bp->flags_fs = set->flags_fs ;
        fs_bp->parent_nr = set->parent_nr ;
        fs_bp->weight = set->weight ;
        fs_bp->qsize = set->qsize ;
        fs_bp->plr = set->plr ;
        fs_bp->flow_mask = set->flow_mask ;
        fs_bp->rq_size = set->rq_size ;
        fs_bp->rq_elements = set->rq_elements ;
        fs_bp->last_expired = set->last_expired ;
        fs_bp->backlogged = set->backlogged ;
        fs_bp->w_q = set->w_q ;
        fs_bp->max_th = set->max_th ;
        fs_bp->min_th = set->min_th ;
        fs_bp->max_p = set->max_p ;
        fs_bp->c_1 = set->c_1 ;
        fs_bp->c_2 = set->c_2 ;
        fs_bp->c_3 = set->c_3 ;
        fs_bp->c_4 = set->c_4 ;
        fs_bp->w_q_lookup = CAST_DOWN_EXPLICIT(user32_addr_t, set->w_q_lookup) ;
        fs_bp->lookup_depth = set->lookup_depth ;
        fs_bp->lookup_step = set->lookup_step ;
        fs_bp->lookup_weight = set->lookup_weight ;
        fs_bp->avg_pkt_size = set->avg_pkt_size ;
        fs_bp->max_pkt_size = set->max_pkt_size ;
}

static void
cp_flow_set_to_64_user(struct dn_flow_set *set, struct dn_flow_set_64 *fs_bp)
{
        fs_bp->fs_nr = set->fs_nr;
        fs_bp->flags_fs = set->flags_fs ;
        fs_bp->parent_nr = set->parent_nr ;
        fs_bp->weight = set->weight ;
        fs_bp->qsize = set->qsize ;
        fs_bp->plr = set->plr ;
        fs_bp->flow_mask = set->flow_mask ;
        fs_bp->rq_size = set->rq_size ;
        fs_bp->rq_elements = set->rq_elements ;
        fs_bp->last_expired = set->last_expired ;
        fs_bp->backlogged = set->backlogged ;
        fs_bp->w_q = set->w_q ;
        fs_bp->max_th = set->max_th ;
        fs_bp->min_th = set->min_th ;
        fs_bp->max_p = set->max_p ;
        fs_bp->c_1 = set->c_1 ;
        fs_bp->c_2 = set->c_2 ;
        fs_bp->c_3 = set->c_3 ;
        fs_bp->c_4 = set->c_4 ;
        fs_bp->w_q_lookup = CAST_DOWN(user64_addr_t, set->w_q_lookup) ;
        fs_bp->lookup_depth = set->lookup_depth ;
        fs_bp->lookup_step = set->lookup_step ;
        fs_bp->lookup_weight = set->lookup_weight ;
        fs_bp->avg_pkt_size = set->avg_pkt_size ;
        fs_bp->max_pkt_size = set->max_pkt_size ;
}

static
void cp_queue_to_32_user( struct dn_flow_queue *q, struct dn_flow_queue_32 *qp)
{
        qp->id = q->id;
        qp->len = q->len;
        qp->len_bytes = q->len_bytes;
        qp->numbytes = q->numbytes;
        qp->tot_pkts = q->tot_pkts;
        qp->tot_bytes = q->tot_bytes;
        qp->drops = q->drops;
        qp->hash_slot = q->hash_slot;
        qp->avg = q->avg;
        qp->count = q->count;
        qp->random = q->random;
        qp->q_time = q->q_time;
        qp->heap_pos = q->heap_pos;
        qp->sched_time = q->sched_time;
        qp->S = q->S;
        qp->F = q->F;
}

static
void cp_queue_to_64_user( struct dn_flow_queue *q, struct dn_flow_queue_64 *qp)
{
        qp->id = q->id;
        qp->len = q->len;
        qp->len_bytes = q->len_bytes;
        qp->numbytes = q->numbytes;
        qp->tot_pkts = q->tot_pkts;
        qp->tot_bytes = q->tot_bytes;
        qp->drops = q->drops;
        qp->hash_slot = q->hash_slot;
        qp->avg = q->avg;
        qp->count = q->count;
        qp->random = q->random;
        qp->q_time = q->q_time;
        qp->heap_pos = q->heap_pos;
        qp->sched_time = q->sched_time;
        qp->S = q->S;
        qp->F = q->F;
}

static
char *cp_pipe_to_32_user(struct dn_pipe *p, struct dn_pipe_32 *pipe_bp)
{
        char    *bp;
        
        pipe_bp->pipe_nr = p->pipe_nr;
        pipe_bp->bandwidth = p->bandwidth;
        bcopy( &(p->scheduler_heap), &(pipe_bp->scheduler_heap), sizeof(struct dn_heap_32));
        pipe_bp->scheduler_heap.p = CAST_DOWN_EXPLICIT(user32_addr_t, pipe_bp->scheduler_heap.p);
        bcopy( &(p->not_eligible_heap), &(pipe_bp->not_eligible_heap), sizeof(struct dn_heap_32));
        pipe_bp->not_eligible_heap.p = CAST_DOWN_EXPLICIT(user32_addr_t, pipe_bp->not_eligible_heap.p);
        bcopy( &(p->idle_heap), &(pipe_bp->idle_heap), sizeof(struct dn_heap_32));
        pipe_bp->idle_heap.p = CAST_DOWN_EXPLICIT(user32_addr_t, pipe_bp->idle_heap.p);
        pipe_bp->V = p->V;
        pipe_bp->sum = p->sum;
        pipe_bp->numbytes = p->numbytes;
        pipe_bp->sched_time = p->sched_time;
        bcopy( p->if_name, pipe_bp->if_name, IFNAMSIZ);
        pipe_bp->ifp = CAST_DOWN_EXPLICIT(user32_addr_t, p->ifp);
        pipe_bp->ready = p->ready;
        
        cp_flow_set_to_32_user( &(p->fs), &(pipe_bp->fs));
        
        pipe_bp->delay = (pipe_bp->delay * 1000) / (hz*10) ; 
        /*
         * 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 = CAST_DOWN_EXPLICIT( user32_addr_t, DN_IS_PIPE );
        /* clean pointers */
        pipe_bp->head = pipe_bp->tail = (user32_addr_t) 0 ;
        pipe_bp->fs.next = (user32_addr_t)0 ;
        pipe_bp->fs.pipe = (user32_addr_t)0 ;
        pipe_bp->fs.rq = (user32_addr_t)0 ;
        bp = ((char *)pipe_bp) + sizeof(struct dn_pipe_32);
        return( dn_copy_set_32( &(p->fs), bp) );
}

static
char *cp_pipe_to_64_user(struct dn_pipe *p, struct dn_pipe_64 *pipe_bp)
{
        char    *bp;
        
        pipe_bp->pipe_nr = p->pipe_nr;
        pipe_bp->bandwidth = p->bandwidth;
        bcopy( &(p->scheduler_heap), &(pipe_bp->scheduler_heap), sizeof(struct dn_heap_64));
        pipe_bp->scheduler_heap.p = CAST_DOWN(user64_addr_t, pipe_bp->scheduler_heap.p);
        bcopy( &(p->not_eligible_heap), &(pipe_bp->not_eligible_heap), sizeof(struct dn_heap_64));
        pipe_bp->not_eligible_heap.p = CAST_DOWN(user64_addr_t, pipe_bp->not_eligible_heap.p);
        bcopy( &(p->idle_heap), &(pipe_bp->idle_heap), sizeof(struct dn_heap_64));
        pipe_bp->idle_heap.p = CAST_DOWN(user64_addr_t, pipe_bp->idle_heap.p);
        pipe_bp->V = p->V;
        pipe_bp->sum = p->sum;
        pipe_bp->numbytes = p->numbytes;
        pipe_bp->sched_time = p->sched_time;
        bcopy( p->if_name, pipe_bp->if_name, IFNAMSIZ);
        pipe_bp->ifp = CAST_DOWN(user64_addr_t, p->ifp);
        pipe_bp->ready = p->ready;
        
        cp_flow_set_to_64_user( &(p->fs), &(pipe_bp->fs));
        
        pipe_bp->delay = (pipe_bp->delay * 1000) / (hz*10) ; 
        /*
         * 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 = CAST_DOWN( user64_addr_t, DN_IS_PIPE );
        /* clean pointers */
        pipe_bp->head = pipe_bp->tail = USER_ADDR_NULL ;
        pipe_bp->fs.next = USER_ADDR_NULL ;
        pipe_bp->fs.pipe = USER_ADDR_NULL ;
        pipe_bp->fs.rq = USER_ADDR_NULL ;
        bp = ((char *)pipe_bp) + sizeof(struct dn_pipe_64);
        return( dn_copy_set_64( &(p->fs), bp) );
}

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

    if (h->size >= new_size ) {
        printf("dummynet: heap_init, Bogus call, have %d want %d\n",
                h->size, new_size);
        return 0 ;
    }
    new_size = (new_size + HEAP_INCREMENT ) & ~HEAP_INCREMENT ;
    p = _MALLOC(new_size * sizeof(*p), M_DUMMYNET, M_DONTWAIT );
    if (p == NULL) {
        printf("dummynet: heap_init, resize %d failed\n", 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, maxelt = h->elements - 1 ;

    if (maxelt < 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 <= maxelt) {           /* valid entry */
        if (child != maxelt && 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 != maxelt) {
        /*
         * Fill hole with last entry and bubble up, reusing the insert code
         */
        h->p[father] = h->p[maxelt] ;
        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 maxelt = 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)) <= maxelt ) { /* found left child */
            if ((temp != maxelt) && 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_id == KERNEL_MODULE_TAG_ID &&
            mtag->m_tag_type == KERNEL_TAG_TYPE_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 ;

        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);

        /* Extract packets only if no pending chain is being currently processed */
        if (serialize == 0) {
                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 the pipe into the heap for next ready 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)
 */
 
/* hz is 100, which gives a granularity of 10ms in the old timer. 
 * The timer has been changed to fire every 1ms, so the use of
 * hz has been modified here. All instances of hz have been left
 * in place but adjusted by a factor of 10 so that hz is functionally 
 * equal to 1000.
 */
#define SET_TICKS(_m, q, p)     \
    ((_m)->m_pkthdr.len*8*(hz*10) - (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 ;

        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);
        
    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*10) : 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;
        q->numbytes = 0;
    }
    /*
     * If the delay line was empty call transmit_event(p) 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;

        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);
        
    if (p->if_name[0] == 0) /* tx clock is simulated */
        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;
            u_int64_t len = pkt->m_pkthdr.len;
            int len_scaled = p->bandwidth ? len*8*(hz*10) : 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)/(u_int64_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 bandwidth >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(p) now.
     * Otherwise, the scheduler will take care of it.
     */
    if (p_was_empty)
                transmit_event(p, head, tail);

}

/*
 * This is called every 1ms. It is used to
 * increment the current tick counter and schedule expired events.
 */
static void
dummynet(__unused void * unused)
{
    void *p ; /* generic parameter to handler */
    struct dn_heap *h ;
    struct dn_heap *heaps[3];
    struct mbuf *head = NULL, *tail = NULL;
    int i;
    struct dn_pipe *pe ;
    struct timespec ts;
    struct timeval      tv;

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

        lck_mtx_lock(dn_mutex);
        
        /* make all time measurements in milliseconds (ms) -  
         * here we convert secs and usecs to msecs (just divide the 
         * usecs and take the closest whole number).
         */
        microuptime(&tv);
        curr_time = (tv.tv_sec * 1000) + (tv.tv_usec / 1000);

    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));
                p = h->p[0].object ; /* store a copy before heap_extract */
                heap_extract(h, NULL); /* need to extract before processing */
                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(pe, &pipehash[i], next)
        if (pe->idle_heap.elements > 0 &&
                DN_KEY_LT(pe->idle_heap.p[0].key, pe->V) ) {
            struct dn_flow_queue *q = pe->idle_heap.p[0].object ;

            heap_extract(&(pe->idle_heap), NULL);
            q->S = q->F + 1 ; /* mark timestamp as invalid */
            pe->sum -= q->fs->weight ;
        }
        
        /* check the heaps to see if there's still stuff in there, and 
         * only set the timer if there are packets to process 
         */
        timer_enabled = 0;
        for (i=0; i < 3 ; i++) {
                h = heaps[i];
                if (h->elements > 0) { // set the timer
                        ts.tv_sec = 0;
                        ts.tv_nsec = 1 * 1000000;       // 1ms
                        timer_enabled = 1;
                        bsd_timeout(dummynet, NULL, &ts);
                        break;
                }
        }

        /* 
         * If a packet chain has been dequeued, set serialize=1 so that new 
         * packets don't get dispatched out of turn 
         */
        if (head != NULL)
                serialize = 1;

    lck_mtx_unlock(dn_mutex);

        /* Send out the de-queued list of ready-to-send packets */
        if (head != NULL) {
                dummynet_send(head);
                lck_mtx_lock(dn_mutex);
                serialize = 0;
                lck_mtx_unlock(dn_mutex);
        }
}


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

        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: {
                        struct route tmp_rt = pkt->ro;
                        (void)ip_output(m, NULL, &tmp_rt, pkt->flags, NULL, NULL);
                        if (tmp_rt.ro_rt) {
                                rtfree(tmp_rt.ro_rt);
                                tmp_rt.ro_rt = NULL;
                        }
                        break ;
                }
                case DN_TO_IP_IN :
                        proto_inject(PF_INET, m);
                        break ;
        
#if BRIDGE
                case DN_TO_BDG_FWD :
                        /*
                         * The bridge requires/assumes the Ethernet header is
                         * contiguous in the first mbuf header.  Insure this is true.
                         */
                        if (BDG_LOADED) {
                        if (m->m_len < ETHER_HDR_LEN &&
                                (m = m_pullup(m, ETHER_HDR_LEN)) == NULL) {
                                printf("dummynet/bridge: pullup fail, dropping pkt\n");
                                break;
                        }
                        m = bdg_forward_ptr(m, pkt->ifp);
                        } else {
                        /* somebody unloaded the bridge module. Drop pkt */
                        /* XXX rate limit */
                        printf("dummynet: dropping bridged packet trapped in pipe\n");
                        }
                        if (m)
                        m_freem(m);
                        break;
#endif          
                default:
                        printf("dummynet: bad switch %d!\n", pkt->dn_dir);
                        m_freem(m);
                        break ;
        }
        }
}


 
/*
 * called by an interface when tx_rdy occurs.
 */
int
if_tx_rdy(struct ifnet *ifp)
{
    struct dn_pipe *p;
        struct mbuf *head = NULL, *tail = NULL;
        int i;
        
        lck_mtx_lock(dn_mutex);
        
        for (i = 0; i < HASHSIZE; i++)
                SLIST_FOREACH(p, &pipehash[i], next)
                if (p->ifp == ifp)
                        break ;
    if (p == NULL) {
        char buf[32];
        snprintf(buf, sizeof(buf), "%s%d",ifp->if_name, ifp->if_unit);
        for (i = 0; i < HASHSIZE; i++)
                SLIST_FOREACH(p, &pipehash[i], next)
            if (!strcmp(p->if_name, buf) ) {
                p->ifp = ifp ;
                DPRINTF(("dummynet: ++ tx rdy from %s (now found)\n", buf));
                break ;
            }
    }
    if (p != NULL) {
        DPRINTF(("dummynet: ++ tx rdy from %s%d - qlen %d\n", ifp->if_name,
                ifp->if_unit, ifp->if_snd.ifq_len));
        p->numbytes = 0 ; /* mark ready for I/O */
        ready_event_wfq(p, &head, &tail);
    }
        lck_mtx_unlock(dn_mutex);

        
        /* Send out the de-queued list of ready-to-send packets */
        if (head != NULL)
                dummynet_send(head);

    return 0;
}

/*
 * 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 ;
        struct timeval timenow;

        getmicrotime(&timenow);

    if (fs->last_expired == timenow.tv_sec)
        return 0 ;
    fs->last_expired = timenow.tv_sec ;
    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_DONTWAIT | 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 */
    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;

    if ( !(fs->flags_fs & DN_HAVE_FLOW_MASK) )
        q = fs->rq[0] ;
    else {
        /* first, do the masking */
        id->dst_ip &= fs->flow_mask.dst_ip ;
        id->src_ip &= fs->flow_mask.src_ip ;
        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 */
        /* then, hash function */
        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 (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 */
            else 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 = (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, and 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), and 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 = MY_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 = MY_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,
 *              real_dst in bdg_forward
 * ro           route parameter (only used in ip_output, NULL otherwise)
 * dst          destination address, only used by ip_output
 * rule         matching rule, in case of multiple passes
 * flags        flags from the caller, only used in ip_output
 *
 */
static int
dummynet_io(struct mbuf *m, int pipe_nr, int dir, struct ip_fw_args *fwa)
{
        struct mbuf *head = NULL, *tail = NULL;
    struct dn_pkt_tag *pkt;
    struct m_tag *mtag;
    struct dn_flow_set *fs = NULL;
    struct dn_pipe *pipe ;
    u_int64_t len = m->m_pkthdr.len ;
    struct dn_flow_queue *q = NULL ;
    int is_pipe;
    struct timespec ts;
    struct timeval      tv;
    
#if IPFW2
    ipfw_insn *cmd = fwa->rule->cmd + fwa->rule->act_ofs;

    if (cmd->opcode == O_LOG)
        cmd += F_LEN(cmd);
    is_pipe = (cmd->opcode == O_PIPE);
#else
    is_pipe = (fwa->rule->fw_flg & IP_FW_F_COMMAND) == IP_FW_F_PIPE;
#endif

    pipe_nr &= 0xffff ;

        lck_mtx_lock(dn_mutex);

        /* make all time measurements in milliseconds (ms) - 
         * here we convert secs and usecs to msecs (just divide the 
         * usecs and take the closest whole number).
         */
        microuptime(&tv);
        curr_time = (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
        
   /*
     * This is a dummynet rule, so we expect an O_PIPE or O_QUEUE rule.
     */
    if (is_pipe) {
                pipe = locate_pipe(pipe_nr);
                if (pipe != NULL)
                        fs = &(pipe->fs);
        } else
                fs = locate_flowset(pipe_nr);
        
        
    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 && (MY_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_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DUMMYNET,
                sizeof(struct dn_pkt_tag), M_NOWAIT);
    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);
    bzero(pkt, sizeof(struct dn_pkt_tag));
    /* 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 (dir == DN_TO_IP_OUT) {
        /*
         * We need to copy *ro because for ICMP pkts (and maybe others)
         * the caller passed a pointer into the stack; dst might also be
         * a pointer into *ro so it needs to be updated.
         */
        pkt->ro = *(fwa->ro);
        if (fwa->ro->ro_rt)
                RT_ADDREF(fwa->ro->ro_rt);

        if (fwa->dst == (struct sockaddr_in *)&fwa->ro->ro_dst) /* dst points into ro */
            fwa->dst = (struct sockaddr_in *)&(pkt->ro.ro_dst) ;

        pkt->dn_dst = fwa->dst;
        pkt->flags = fwa->flags;
        if (fwa->ipoa != NULL)
                pkt->ipoa = *(fwa->ipoa);
        }
    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 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)
            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 )/(u_int64_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:
        /* start the timer and set global if not already set */
        if (!timer_enabled) {
                ts.tv_sec = 0;
                ts.tv_nsec = 1 * 1000000;       // 1ms
                timer_enabled = 1;
                bsd_timeout(dummynet, NULL, &ts);
    }

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

    return 0;

dropit:
    if (q)
        q->drops++ ;
        lck_mtx_unlock(dn_mutex);
    m_freem(m);
    return ( (fs && (fs->flags_fs & DN_NOERROR)) ? 0 : ENOBUFS);
}

/*
 * Below, the rtfree 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 {                                    \
        struct m_tag *tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DUMMYNET, NULL); \
        if (tag) {                                              \
                struct dn_pkt_tag *n = (struct dn_pkt_tag *)(tag+1);    \
                if (n->ro.ro_rt != NULL) {                      \
                        rtfree(n->ro.ro_rt);                    \
                        n->ro.ro_rt = NULL;                     \
                }                                               \
        }                                                       \
        m_tag_delete(_m, tag);                                  \
        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 ;

        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);

    for (i = 0 ; i <= fs->rq_size ; i++ ) {
        for (q = fs->rq[i] ; q ; 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)
            FREE(fs->w_q_lookup, M_DUMMYNET);
        if (fs->rq)
            FREE(fs->rq, M_DUMMYNET);
        /* if this fs is not part of a pipe, free it */
        if (fs->pipe && 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;

        lck_mtx_lock(dn_mutex);

    /* remove all references to pipes ...*/
    flush_pipe_ptrs(NULL);
 
        /* 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);
                }
        lck_mtx_unlock(dn_mutex);
}


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 *p ;
    struct dn_flow_set *fs ;
    struct dn_pkt_tag *pkt ;
    struct mbuf *m ;
    int i;

        lck_mtx_lock(dn_mutex);

    /*
     * 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(p, &pipehash[i], next) {
                fs = &(p->fs);
                dn_rule_delete_fs(fs, r);
                for (m = p->head ; m ; m = m->m_nextpkt ) {
                        pkt = dn_tag_get(m);
                        if (pkt->rule == r)
                                pkt->rule = ip_fw_default_rule;
                }
        }
        lck_mtx_unlock(dn_mutex);
}

/*
 * 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_DONTWAIT);
    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_DONTWAIT | M_ZERO);
    if (x->rq == NULL) {
        printf("dummynet: sorry, cannot allocate queue\n");
        return ENOSPC;
    }
    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 > 1024*1024)
            x->qsize = 1024*1024 ;
    } else {
        if (x->qsize == 0)
            x->qsize = 50 ;
        if (x->qsize > 100)
            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)
{
    int i, r;
    struct dn_flow_set *pfs = &(p->fs);
    struct dn_flow_queue *q;

    /*
     * 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*10) ) / 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 *x, *b;

        lck_mtx_lock(dn_mutex);

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

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


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

        lck_mtx_lock(dn_mutex);
        /* locate flow_set */
        b = locate_flowset(pfs->fs_nr);

        if (b == NULL || b->fs_nr != pfs->fs_nr) { /* new  */
            if (pfs->parent_nr == 0) {  /* need link to a pipe */
                lck_mtx_unlock(dn_mutex);
                        return EINVAL ;
                }
            x = _MALLOC(sizeof(struct dn_flow_set), M_DUMMYNET, M_DONTWAIT | M_ZERO);
            if (x == NULL) {
                lck_mtx_unlock(dn_mutex);
                        printf("dummynet: no memory for new flow_set\n");
                        return ENOSPC;
            }
            x->fs_nr = pfs->fs_nr;
            x->parent_nr = pfs->parent_nr;
            x->weight = pfs->weight ;
            if (x->weight == 0)
                x->weight = 1 ;
            else if (x->weight > 100)
                x->weight = 100 ;
        } else {
            /* Change parent pipe not allowed; must delete and recreate */
            if (pfs->parent_nr != 0 && b->parent_nr != pfs->parent_nr) {
                lck_mtx_unlock(dn_mutex);
                        return EINVAL ;
                }
            x = b;
        }
        set_fs_parms(x, pfs);

        if ( x->rq == NULL ) { /* a new flow_set */
            r = alloc_hash(x, pfs) ;
            if (r) {
                lck_mtx_unlock(dn_mutex);
                FREE(x, M_DUMMYNET);
                return r ;
            }
            SLIST_INSERT_HEAD(&flowsethash[HASH(x->fs_nr)],
                            x, next);
        }
        lck_mtx_unlock(dn_mutex);
    }
    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 *p;
    struct mbuf *m, *mnext;
        int i;

        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);

    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(p, &pipehash[i], next) {
                purge_flow_set(&(p->fs), 0);    

        mnext = p->head;
        while ((m = mnext) != NULL) {
            mnext = m->m_nextpkt;
            DN_FREE_PKT(m);
        }
        p->head = p->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 *b;
        struct dn_flow_set *fs;
        int i;

        lck_mtx_lock(dn_mutex);
        /* locate pipe */
        b = locate_pipe(p->pipe_nr);
        if(b == NULL){
                lck_mtx_unlock(dn_mutex);
            return EINVAL ; /* not found */
        }

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

        /* remove references to this pipe from the ip_fw rules. */
        flush_pipe_ptrs(&(b->fs));

        /* Remove all references to this pipe from flow_sets. */
        for (i = 0; i < HASHSIZE; i++)
            SLIST_FOREACH(fs, &flowsethash[i], next)
                if (fs->pipe == b) {
                        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, &(b->fs));

        purge_pipe(b);  /* remove all data associated to this pipe */
        /* remove reference to here from extract_heap and wfq_ready_heap */
        pipe_remove_from_heap(&extract_heap, b);
        pipe_remove_from_heap(&wfq_ready_heap, b);
        lck_mtx_unlock(dn_mutex);
        
        FREE(b, M_DUMMYNET);
    } else { /* this is a WF2Q queue (dn_flow_set) */
        struct dn_flow_set *b;

        lck_mtx_lock(dn_mutex);
        /* locate set */
        b = locate_flowset(p->fs.fs_nr);
        if (b == NULL) {
                lck_mtx_unlock(dn_mutex);
            return EINVAL ; /* not found */
        }

        /* remove references to this flow_set from the ip_fw rules. */
        flush_pipe_ptrs(b);

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

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

/*
 * helper function used to copy data from kernel in DUMMYNET_GET
 */
static 
char* dn_copy_set_32(struct dn_flow_set *set, char *bp)
{
    int i, copied = 0 ;
    struct dn_flow_queue *q;
        struct dn_flow_queue_32 *qp = (struct dn_flow_queue_32 *)bp;
        
        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);
        
    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++ ;
                        cp_queue_to_32_user( q, qp );
                        /* cleanup pointers */
                        qp->next = (user32_addr_t)0 ;
                        qp->head = qp->tail = (user32_addr_t)0 ;
                        qp->fs = (user32_addr_t)0 ;
                }
    if (copied != set->rq_elements)
                printf("dummynet: ++ wrong count, have %d should be %d\n",
                           copied, set->rq_elements);
    return (char *)qp ;
}

static 
char* dn_copy_set_64(struct dn_flow_set *set, char *bp)
{
    int i, copied = 0 ;
    struct dn_flow_queue *q;
        struct dn_flow_queue_64 *qp = (struct dn_flow_queue_64 *)bp;
        
        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);
        
    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));
                        cp_queue_to_64_user( q, qp );
                        /* cleanup pointers */
                        qp->next = USER_ADDR_NULL ;
                        qp->head = qp->tail = USER_ADDR_NULL ;
                        qp->fs = USER_ADDR_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(int is64user)
{
    struct dn_flow_set *set ;
    struct dn_pipe *p ;
    size_t size = 0 ;
        size_t pipesize;
        size_t queuesize;
        size_t setsize;
        int i;

        lck_mtx_assert(dn_mutex, LCK_MTX_ASSERT_OWNED);
        if ( is64user ){
                pipesize = sizeof(struct dn_pipe_64);
                queuesize = sizeof(struct dn_flow_queue_64);
                setsize = sizeof(struct dn_flow_set_64);
        }
        else {
                pipesize = sizeof(struct dn_pipe_32);
                queuesize = sizeof( struct dn_flow_queue_32 );
                setsize = sizeof(struct dn_flow_set_32);
        }
    /*
     * compute size of data structures: list of pipes and flow_sets.
     */
    for (i = 0; i < HASHSIZE; i++) {
        SLIST_FOREACH(p, &pipehash[i], next)
                size += sizeof(*p) +
                    p->fs.rq_elements * sizeof(struct dn_flow_queue);
        SLIST_FOREACH(set, &flowsethash[i], next)
                size += sizeof (*set) +
                    set->rq_elements * sizeof(struct dn_flow_queue);
    }
    return size;
}

static int
dummynet_get(struct sockopt *sopt)
{
    char *buf, *bp=NULL; /* bp is the "copy-pointer" */
    size_t size ;
    struct dn_flow_set *set ;
    struct dn_pipe *p ;
    int error=0, i ;
        int     is64user = 0;

    /* XXX lock held too long */
    lck_mtx_lock(dn_mutex);
    /*
     * XXX: Ugly, but we need to allocate memory with M_WAITOK flag and we
     *      cannot use this flag while holding a mutex.
     */
        if (proc_is64bit(sopt->sopt_p))
                is64user = 1;
    for (i = 0; i < 10; i++) {
                size = dn_calc_size(is64user);
                lck_mtx_unlock(dn_mutex);
                buf = _MALLOC(size, M_TEMP, M_WAITOK);
                if (buf == NULL)
                        return ENOBUFS;
                lck_mtx_lock(dn_mutex);
                if (size == dn_calc_size(is64user))
                        break;
                FREE(buf, M_TEMP);
                buf = NULL;
    }
    if (buf == NULL) {
                lck_mtx_unlock(dn_mutex);
                return ENOBUFS ;
    }


    bp = buf;
    for (i = 0; i < HASHSIZE; i++)
        SLIST_FOREACH(p, &pipehash[i], next) {
                /*
                 * 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.
                 */
                if ( is64user ){
                        bp = cp_pipe_to_64_user(p, (struct dn_pipe_64 *)bp);
                }
                else{
                        bp = cp_pipe_to_32_user(p, (struct dn_pipe_32 *)bp);
                }
    }
        for (i = 0; i < HASHSIZE; i++)
        SLIST_FOREACH(set, &flowsethash[i], next) {
                struct dn_flow_set_64 *fs_bp = (struct dn_flow_set_64 *)bp ;
                cp_flow_set_to_64_user(set, fs_bp);
                /* XXX same hack as above */
                fs_bp->next = CAST_DOWN(user64_addr_t, DN_IS_QUEUE);
                fs_bp->pipe = USER_ADDR_NULL;
                fs_bp->rq = USER_ADDR_NULL ;
                bp += sizeof(struct dn_flow_set_64);
                bp = dn_copy_set_64( set, bp );
    }
    lck_mtx_unlock(dn_mutex);

    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;

    /* Disallow sets in really-really secure mode. */
    if (sopt->sopt_dir == SOPT_SET && securelevel >= 3)
        return (EPERM);

    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 ;
        if (proc_is64bit(sopt->sopt_p))
                error = cp_pipe_from_user_64( sopt, p );
        else
                error = cp_pipe_from_user_32( sopt, p );

        if (error)
            break ;
        error = config_pipe(p);
        break ;

    case IP_DUMMYNET_DEL :      /* remove a pipe or queue */
        p = &tmp_pipe ;
        if (proc_is64bit(sopt->sopt_p))
                error = cp_pipe_from_user_64( sopt, p );
        else
                error = cp_pipe_from_user_32( sopt, p );
        if (error)
            break ;

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

void
ip_dn_init(void)
{
        /* setup locks */
        dn_mutex_grp_attr = lck_grp_attr_alloc_init();
        dn_mutex_grp = lck_grp_alloc_init("dn", dn_mutex_grp_attr);
        dn_mutex_attr = lck_attr_alloc_init();

        if ((dn_mutex = lck_mtx_alloc_init(dn_mutex_grp, dn_mutex_attr)) == NULL) {
                printf("ip_dn_init: can't alloc dn_mutex\n");
                return;
        }

        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;
}