FreeBSD/Linux Kernel Cross Reference
sys/netpfil/ipfw/ip_dummynet.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Codel/FQ_Codel and PIE/FQ-PIE Code:
      * Copyright (C) 2016 Centre for Advanced Internet Architectures,
      *  Swinburne University of Technology, Melbourne, Australia.
      * Portions of this code were made possible in part by a gift from 
      *  The Comcast Innovation Fund.
      * Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au>
     * 
     * Copyright (c) 1998-2002,2010 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("$FreeBSD$");
    
    /*
     * Configuration and internal object management for dummynet.
     */
    
    #include "opt_inet6.h"
    
    #include <sys/param.h>
    #include <sys/ck.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/rwlock.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/time.h>
    #include <sys/taskqueue.h>
    #include <net/if.h>     /* IFNAMSIZ, struct ifaddr, ifq head, lock.h mutex.h */
    #include <netinet/in.h>
    #include <netinet/ip_var.h>     /* ip_output(), IP_FORWARDING */
    #include <netinet/ip_fw.h>
    #include <netinet/ip_dummynet.h>
    #include <net/vnet.h>
    
    #include <netpfil/ipfw/ip_fw_private.h>
    #include <netpfil/ipfw/dn_heap.h>
    #include <netpfil/ipfw/ip_dn_private.h>
    #ifdef NEW_AQM
    #include <netpfil/ipfw/dn_aqm.h>
    #endif
    #include <netpfil/ipfw/dn_sched.h>
    
    /* which objects to copy */
    #define DN_C_LINK       0x01
    #define DN_C_SCH        0x02
    #define DN_C_FLOW       0x04
    #define DN_C_FS         0x08
    #define DN_C_QUEUE      0x10
    
    /* we use this argument in case of a schk_new */
    struct schk_new_arg {
            struct dn_alg *fp;
            struct dn_sch *sch;
    };
    
    /*---- callout hooks. ----*/
    static struct callout dn_timeout;
    static int dn_tasks_started = 0;
    static int dn_gone;
    static struct task      dn_task;
    static struct taskqueue *dn_tq = NULL;
    
    /* global scheduler list */
    struct mtx              sched_mtx;
    CK_LIST_HEAD(, dn_alg)  schedlist;
   #ifdef NEW_AQM
   CK_LIST_HEAD(, dn_aqm)  aqmlist;        /* list of AQMs */
   #endif
   
   static void
   dummynet(void *arg)
   {
   
           (void)arg;      /* UNUSED */
           taskqueue_enqueue(dn_tq, &dn_task);
   }
   
   void
   dummynet_sched_lock(void)
   {
           mtx_lock(&sched_mtx);
   }
   
   void
   dummynet_sched_unlock(void)
   {
           mtx_unlock(&sched_mtx);
   }
   
   void
   dn_reschedule(void)
   {
   
           if (dn_gone != 0)
                   return;
           callout_reset_sbt(&dn_timeout, tick_sbt, 0, dummynet, NULL,
               C_HARDCLOCK | C_DIRECT_EXEC);
   }
   /*----- end of callout hooks -----*/
   
   #ifdef NEW_AQM
   /* Return AQM descriptor for given type or name. */
   static struct dn_aqm *
   find_aqm_type(int type, char *name)
   {
           struct dn_aqm *d;
   
           NET_EPOCH_ASSERT();
   
           CK_LIST_FOREACH(d, &aqmlist, next) {
                   if (d->type == type || (name && !strcasecmp(d->name, name)))
                           return d;
           }
           return NULL; /* not found */
   }
   #endif
   
   /* Return a scheduler descriptor given the type or name. */
   static struct dn_alg *
   find_sched_type(int type, char *name)
   {
           struct dn_alg *d;
   
           NET_EPOCH_ASSERT();
   
           CK_LIST_FOREACH(d, &schedlist, next) {
                   if (d->type == type || (name && !strcasecmp(d->name, name)))
                           return d;
           }
           return NULL; /* not found */
   }
   
   int
   ipdn_bound_var(int *v, int dflt, int lo, int hi, const char *msg)
   {
           int oldv = *v;
           const char *op = NULL;
           if (dflt < lo)
                   dflt = lo;
           if (dflt > hi)
                   dflt = hi;
           if (oldv < lo) {
                   *v = dflt;
                   op = "Bump";
           } else if (oldv > hi) {
                   *v = hi;
                   op = "Clamp";
           } else
                   return *v;
           if (op && msg && bootverbose)
                   printf("%s %s to %d (was %d)\n", op, msg, *v, oldv);
           return *v;
   }
   
   /*---- flow_id mask, hash and compare functions ---*/
   /*
    * The flow_id includes the 5-tuple, the queue/pipe number
    * which we store in the extra area in host order,
    * and for ipv6 also the flow_id6.
    * XXX see if we want the tos byte (can store in 'flags')
    */
   static struct ipfw_flow_id *
   flow_id_mask(struct ipfw_flow_id *mask, struct ipfw_flow_id *id)
   {
           int is_v6 = IS_IP6_FLOW_ID(id);
   
           id->dst_port &= mask->dst_port;
           id->src_port &= mask->src_port;
           id->proto &= mask->proto;
           id->extra &= mask->extra;
           if (is_v6) {
                   APPLY_MASK(&id->dst_ip6, &mask->dst_ip6);
                   APPLY_MASK(&id->src_ip6, &mask->src_ip6);
                   id->flow_id6 &= mask->flow_id6;
           } else {
                   id->dst_ip &= mask->dst_ip;
                   id->src_ip &= mask->src_ip;
           }
           return id;
   }
   
   /* computes an OR of two masks, result in dst and also returned */
   static struct ipfw_flow_id *
   flow_id_or(struct ipfw_flow_id *src, struct ipfw_flow_id *dst)
   {
           int is_v6 = IS_IP6_FLOW_ID(dst);
   
           dst->dst_port |= src->dst_port;
           dst->src_port |= src->src_port;
           dst->proto |= src->proto;
           dst->extra |= src->extra;
           if (is_v6) {
   #define OR_MASK(_d, _s)                          \
       (_d)->__u6_addr.__u6_addr32[0] |= (_s)->__u6_addr.__u6_addr32[0]; \
       (_d)->__u6_addr.__u6_addr32[1] |= (_s)->__u6_addr.__u6_addr32[1]; \
       (_d)->__u6_addr.__u6_addr32[2] |= (_s)->__u6_addr.__u6_addr32[2]; \
       (_d)->__u6_addr.__u6_addr32[3] |= (_s)->__u6_addr.__u6_addr32[3];
                   OR_MASK(&dst->dst_ip6, &src->dst_ip6);
                   OR_MASK(&dst->src_ip6, &src->src_ip6);
   #undef OR_MASK
                   dst->flow_id6 |= src->flow_id6;
           } else {
                   dst->dst_ip |= src->dst_ip;
                   dst->src_ip |= src->src_ip;
           }
           return dst;
   }
   
   static int
   nonzero_mask(struct ipfw_flow_id *m)
   {
           if (m->dst_port || m->src_port || m->proto || m->extra)
                   return 1;
           if (IS_IP6_FLOW_ID(m)) {
                   return
                           m->dst_ip6.__u6_addr.__u6_addr32[0] ||
                           m->dst_ip6.__u6_addr.__u6_addr32[1] ||
                           m->dst_ip6.__u6_addr.__u6_addr32[2] ||
                           m->dst_ip6.__u6_addr.__u6_addr32[3] ||
                           m->src_ip6.__u6_addr.__u6_addr32[0] ||
                           m->src_ip6.__u6_addr.__u6_addr32[1] ||
                           m->src_ip6.__u6_addr.__u6_addr32[2] ||
                           m->src_ip6.__u6_addr.__u6_addr32[3] ||
                           m->flow_id6;
           } else {
                   return m->dst_ip || m->src_ip;
           }
   }
   
   /* XXX we may want a better hash function */
   static uint32_t
   flow_id_hash(struct ipfw_flow_id *id)
   {
       uint32_t i;
   
       if (IS_IP6_FLOW_ID(id)) {
           uint32_t *d = (uint32_t *)&id->dst_ip6;
           uint32_t *s = (uint32_t *)&id->src_ip6;
           i = (d[0]      ) ^ (d[1])       ^
               (d[2]      ) ^ (d[3])       ^
               (d[0] >> 15) ^ (d[1] >> 15) ^
               (d[2] >> 15) ^ (d[3] >> 15) ^
               (s[0] <<  1) ^ (s[1] <<  1) ^
               (s[2] <<  1) ^ (s[3] <<  1) ^
               (s[0] << 16) ^ (s[1] << 16) ^
               (s[2] << 16) ^ (s[3] << 16) ^
               (id->dst_port << 1) ^ (id->src_port) ^
               (id->extra) ^
               (id->proto ) ^ (id->flow_id6);
       } else {
           i = (id->dst_ip)        ^ (id->dst_ip >> 15) ^
               (id->src_ip << 1)   ^ (id->src_ip >> 16) ^
               (id->extra) ^
               (id->dst_port << 1) ^ (id->src_port)     ^ (id->proto);
       }
       return i;
   }
   
   /* Like bcmp, returns 0 if ids match, 1 otherwise. */
   static int
   flow_id_cmp(struct ipfw_flow_id *id1, struct ipfw_flow_id *id2)
   {
           int is_v6 = IS_IP6_FLOW_ID(id1);
   
           if (!is_v6) {
               if (IS_IP6_FLOW_ID(id2))
                   return 1; /* different address families */
   
               return (id1->dst_ip == id2->dst_ip &&
                       id1->src_ip == id2->src_ip &&
                       id1->dst_port == id2->dst_port &&
                       id1->src_port == id2->src_port &&
                       id1->proto == id2->proto &&
                       id1->extra == id2->extra) ? 0 : 1;
           }
           /* the ipv6 case */
           return (
               !bcmp(&id1->dst_ip6,&id2->dst_ip6, sizeof(id1->dst_ip6)) &&
               !bcmp(&id1->src_ip6,&id2->src_ip6, sizeof(id1->src_ip6)) &&
               id1->dst_port == id2->dst_port &&
               id1->src_port == id2->src_port &&
               id1->proto == id2->proto &&
               id1->extra == id2->extra &&
               id1->flow_id6 == id2->flow_id6) ? 0 : 1;
   }
   /*--------- end of flow-id mask, hash and compare ---------*/
   
   /*--- support functions for the qht hashtable ----
    * Entries are hashed by flow-id
    */
   static uint32_t
   q_hash(uintptr_t key, int flags, void *arg)
   {
           /* compute the hash slot from the flow id */
           struct ipfw_flow_id *id = (flags & DNHT_KEY_IS_OBJ) ?
                   &((struct dn_queue *)key)->ni.fid :
                   (struct ipfw_flow_id *)key;
   
           return flow_id_hash(id);
   }
   
   static int
   q_match(void *obj, uintptr_t key, int flags, void *arg)
   {
           struct dn_queue *o = (struct dn_queue *)obj;
           struct ipfw_flow_id *id2;
   
           if (flags & DNHT_KEY_IS_OBJ) {
                   /* compare pointers */
                   id2 = &((struct dn_queue *)key)->ni.fid;
           } else {
                   id2 = (struct ipfw_flow_id *)key;
           }
           return (0 == flow_id_cmp(&o->ni.fid,  id2));
   }
   
   /*
    * create a new queue instance for the given 'key'.
    */
   static void *
   q_new(uintptr_t key, int flags, void *arg)
   {   
           struct dn_queue *q, *template = arg;
           struct dn_fsk *fs = template->fs;
           int size = sizeof(*q) + fs->sched->fp->q_datalen;
   
           q = malloc(size, M_DUMMYNET, M_NOWAIT | M_ZERO);
           if (q == NULL) {
                   D("no memory for new queue");
                   return NULL;
           }
   
           set_oid(&q->ni.oid, DN_QUEUE, size);
           if (fs->fs.flags & DN_QHT_HASH)
                   q->ni.fid = *(struct ipfw_flow_id *)key;
           q->fs = fs;
           q->_si = template->_si;
           q->_si->q_count++;
   
           if (fs->sched->fp->new_queue)
                   fs->sched->fp->new_queue(q);
   
   #ifdef NEW_AQM
           /* call AQM init function after creating a queue*/
           if (fs->aqmfp && fs->aqmfp->init)
                   if(fs->aqmfp->init(q))
                           D("unable to init AQM for fs %d", fs->fs.fs_nr);
   #endif
           V_dn_cfg.queue_count++;
   
           return q;
   }
   
   /*
    * Notify schedulers that a queue is going away.
    * If (flags & DN_DESTROY), also free the packets.
    * The version for callbacks is called q_delete_cb().
    */
   static void
   dn_delete_queue(struct dn_queue *q, int flags)
   {
           struct dn_fsk *fs = q->fs;
   
   #ifdef NEW_AQM
           /* clean up AQM status for queue 'q'
            * cleanup here is called just with MULTIQUEUE
            */
           if (fs && fs->aqmfp && fs->aqmfp->cleanup)
                   fs->aqmfp->cleanup(q);
   #endif
           // D("fs %p si %p\n", fs, q->_si);
           /* notify the parent scheduler that the queue is going away */
           if (fs && fs->sched->fp->free_queue)
                   fs->sched->fp->free_queue(q);
           q->_si->q_count--;
           q->_si = NULL;
           if (flags & DN_DESTROY) {
                   if (q->mq.head)
                           dn_free_pkts(q->mq.head);
                   bzero(q, sizeof(*q));   // safety
                   free(q, M_DUMMYNET);
                   V_dn_cfg.queue_count--;
           }
   }
   
   static int
   q_delete_cb(void *q, void *arg)
   {
           int flags = (int)(uintptr_t)arg;
           dn_delete_queue(q, flags);
           return (flags & DN_DESTROY) ? DNHT_SCAN_DEL : 0;
   }
   
   /*
    * calls dn_delete_queue/q_delete_cb on all queues,
    * which notifies the parent scheduler and possibly drains packets.
    * flags & DN_DESTROY: drains queues and destroy qht;
    */
   static void
   qht_delete(struct dn_fsk *fs, int flags)
   {
           ND("fs %d start flags %d qht %p",
                   fs->fs.fs_nr, flags, fs->qht);
           if (!fs->qht)
                   return;
           if (fs->fs.flags & DN_QHT_HASH) {
                   dn_ht_scan(fs->qht, q_delete_cb, (void *)(uintptr_t)flags);
                   if (flags & DN_DESTROY) {
                           dn_ht_free(fs->qht, 0);
                           fs->qht = NULL;
                   }
           } else {
                   dn_delete_queue((struct dn_queue *)(fs->qht), flags);
                   if (flags & DN_DESTROY)
                           fs->qht = NULL;
           }
   }
   
   /*
    * Find and possibly create the queue for a MULTIQUEUE scheduler.
    * We never call it for !MULTIQUEUE (the queue is in the sch_inst).
    */
   struct dn_queue *
   ipdn_q_find(struct dn_fsk *fs, struct dn_sch_inst *si,
           struct ipfw_flow_id *id)
   {
           struct dn_queue template;
   
           template._si = si;
           template.fs = fs;
   
           if (fs->fs.flags & DN_QHT_HASH) {
                   struct ipfw_flow_id masked_id;
                   if (fs->qht == NULL) {
                           fs->qht = dn_ht_init(NULL, fs->fs.buckets,
                                   offsetof(struct dn_queue, q_next),
                                   q_hash, q_match, q_new);
                           if (fs->qht == NULL)
                                   return NULL;
                   }
                   masked_id = *id;
                   flow_id_mask(&fs->fsk_mask, &masked_id);
                   return dn_ht_find(fs->qht, (uintptr_t)&masked_id,
                           DNHT_INSERT, &template);
           } else {
                   if (fs->qht == NULL)
                           fs->qht = q_new(0, 0, &template);
                   return (struct dn_queue *)fs->qht;
           }
   }
   /*--- end of queue hash table ---*/
   
   /*--- support functions for the sch_inst hashtable ----
    *
    * These are hashed by flow-id
    */
   static uint32_t
   si_hash(uintptr_t key, int flags, void *arg)
   {
           /* compute the hash slot from the flow id */
           struct ipfw_flow_id *id = (flags & DNHT_KEY_IS_OBJ) ?
                   &((struct dn_sch_inst *)key)->ni.fid :
                   (struct ipfw_flow_id *)key;
   
           return flow_id_hash(id);
   }
   
   static int
   si_match(void *obj, uintptr_t key, int flags, void *arg)
   {
           struct dn_sch_inst *o = obj;
           struct ipfw_flow_id *id2;
   
           id2 = (flags & DNHT_KEY_IS_OBJ) ?
                   &((struct dn_sch_inst *)key)->ni.fid :
                   (struct ipfw_flow_id *)key;
           return flow_id_cmp(&o->ni.fid,  id2) == 0;
   }
   
   /*
    * create a new instance for the given 'key'
    * Allocate memory for instance, delay line and scheduler private data.
    */
   static void *
   si_new(uintptr_t key, int flags, void *arg)
   {
           struct dn_schk *s = arg;
           struct dn_sch_inst *si;
           int l = sizeof(*si) + s->fp->si_datalen;
   
           si = malloc(l, M_DUMMYNET, M_NOWAIT | M_ZERO);
           if (si == NULL)
                   goto error;
   
           /* Set length only for the part passed up to userland. */
           set_oid(&si->ni.oid, DN_SCH_I, sizeof(struct dn_flow));
           set_oid(&(si->dline.oid), DN_DELAY_LINE,
                   sizeof(struct delay_line));
           /* mark si and dline as outside the event queue */
           si->ni.oid.id = si->dline.oid.id = -1;
   
           si->sched = s;
           si->dline.si = si;
   
           if (s->fp->new_sched && s->fp->new_sched(si)) {
                   D("new_sched error");
                   goto error;
           }
           if (s->sch.flags & DN_HAVE_MASK)
                   si->ni.fid = *(struct ipfw_flow_id *)key;
   
   #ifdef NEW_AQM
           /* init AQM status for !DN_MULTIQUEUE sched*/
           if (!(s->fp->flags & DN_MULTIQUEUE))
                   if (s->fs->aqmfp && s->fs->aqmfp->init)
                           if(s->fs->aqmfp->init((struct dn_queue *)(si + 1))) {
                                   D("unable to init AQM for fs %d", s->fs->fs.fs_nr);
                                   goto error;
                           }
   #endif
   
           V_dn_cfg.si_count++;
           return si;
   
   error:
           if (si) {
                   bzero(si, sizeof(*si)); // safety
                   free(si, M_DUMMYNET);
           }
           return NULL;
   }
   
   /*
    * Callback from siht to delete all scheduler instances. Remove
    * si and delay line from the system heap, destroy all queues.
    * We assume that all flowset have been notified and do not
    * point to us anymore.
    */
   static int
   si_destroy(void *_si, void *arg)
   {
           struct dn_sch_inst *si = _si;
           struct dn_schk *s = si->sched;
           struct delay_line *dl = &si->dline;
   
           if (dl->oid.subtype) /* remove delay line from event heap */
                   heap_extract(&V_dn_cfg.evheap, dl);
           dn_free_pkts(dl->mq.head);      /* drain delay line */
           if (si->kflags & DN_ACTIVE) /* remove si from event heap */
                   heap_extract(&V_dn_cfg.evheap, si);
   
   #ifdef NEW_AQM
           /* clean up AQM status for !DN_MULTIQUEUE sched
            * Note that all queues belong to fs were cleaned up in fsk_detach.
            * When drain_scheduler is called s->fs and q->fs are pointing 
            * to a correct fs, so we can use fs in this case.
            */
           if (!(s->fp->flags & DN_MULTIQUEUE)) {
                   struct dn_queue *q = (struct dn_queue *)(si + 1);
                   if (q->aqm_status && q->fs->aqmfp)
                           if (q->fs->aqmfp->cleanup)
                                   q->fs->aqmfp->cleanup(q);
           }
   #endif
           if (s->fp->free_sched)
                   s->fp->free_sched(si);
           bzero(si, sizeof(*si)); /* safety */
           free(si, M_DUMMYNET);
           V_dn_cfg.si_count--;
           return DNHT_SCAN_DEL;
   }
   
   /*
    * Find the scheduler instance for this packet. If we need to apply
    * a mask, do on a local copy of the flow_id to preserve the original.
    * Assume siht is always initialized if we have a mask.
    */
   struct dn_sch_inst *
   ipdn_si_find(struct dn_schk *s, struct ipfw_flow_id *id)
   {
   
           if (s->sch.flags & DN_HAVE_MASK) {
                   struct ipfw_flow_id id_t = *id;
                   flow_id_mask(&s->sch.sched_mask, &id_t);
                   return dn_ht_find(s->siht, (uintptr_t)&id_t,
                           DNHT_INSERT, s);
           }
           if (!s->siht)
                   s->siht = si_new(0, 0, s);
           return (struct dn_sch_inst *)s->siht;
   }
   
   /* callback to flush credit for the scheduler instance */
   static int
   si_reset_credit(void *_si, void *arg)
   {
           struct dn_sch_inst *si = _si;
           struct dn_link *p = &si->sched->link;
   
           si->credit = p->burst + (V_dn_cfg.io_fast ?  p->bandwidth : 0);
           return 0;
   }
   
   static void
   schk_reset_credit(struct dn_schk *s)
   {
           if (s->sch.flags & DN_HAVE_MASK)
                   dn_ht_scan(s->siht, si_reset_credit, NULL);
           else if (s->siht)
                   si_reset_credit(s->siht, NULL);
   }
   /*---- end of sch_inst hashtable ---------------------*/
   
   /*-------------------------------------------------------
    * flowset hash (fshash) support. Entries are hashed by fs_nr.
    * New allocations are put in the fsunlinked list, from which
    * they are removed when they point to a specific scheduler.
    */
   static uint32_t
   fsk_hash(uintptr_t key, int flags, void *arg)
   {
           uint32_t i = !(flags & DNHT_KEY_IS_OBJ) ? key :
                   ((struct dn_fsk *)key)->fs.fs_nr;
   
           return ( (i>>8)^(i>>4)^i );
   }
   
   static int
   fsk_match(void *obj, uintptr_t key, int flags, void *arg)
   {
           struct dn_fsk *fs = obj;
           int i = !(flags & DNHT_KEY_IS_OBJ) ? key :
                   ((struct dn_fsk *)key)->fs.fs_nr;
   
           return (fs->fs.fs_nr == i);
   }
   
   static void *
   fsk_new(uintptr_t key, int flags, void *arg)
   {
           struct dn_fsk *fs;
   
           fs = malloc(sizeof(*fs), M_DUMMYNET, M_NOWAIT | M_ZERO);
           if (fs) {
                   set_oid(&fs->fs.oid, DN_FS, sizeof(fs->fs));
                   V_dn_cfg.fsk_count++;
                   fs->drain_bucket = 0;
                   SLIST_INSERT_HEAD(&V_dn_cfg.fsu, fs, sch_chain);
           }
           return fs;
   }
   
   #ifdef NEW_AQM
   /* callback function for cleaning up AQM queue status belongs to a flowset
    * connected to scheduler instance '_si' (for !DN_MULTIQUEUE only).
    */
   static int
   si_cleanup_q(void *_si, void *arg)
   {
           struct dn_sch_inst *si = _si;
   
           if (!(si->sched->fp->flags & DN_MULTIQUEUE)) {
                   if (si->sched->fs->aqmfp && si->sched->fs->aqmfp->cleanup)
                           si->sched->fs->aqmfp->cleanup((struct dn_queue *) (si+1));
           }
           return 0;
   }
   
   /* callback to clean up queue AQM status.*/
   static int
   q_cleanup_q(void *_q, void *arg)
   {
           struct dn_queue *q = _q;
           q->fs->aqmfp->cleanup(q);
           return 0;
   }
   
   /* Clean up all AQM queues status belongs to flowset 'fs' and then
    * deconfig AQM for flowset 'fs'
    */
   static void 
   aqm_cleanup_deconfig_fs(struct dn_fsk *fs)
   {
           struct dn_sch_inst *si;
   
           /* clean up AQM status for all queues for !DN_MULTIQUEUE sched*/
           if (fs->fs.fs_nr > DN_MAX_ID) {
                   if (fs->sched && !(fs->sched->fp->flags & DN_MULTIQUEUE)) {
                           if (fs->sched->sch.flags & DN_HAVE_MASK)
                                   dn_ht_scan(fs->sched->siht, si_cleanup_q, NULL);
                           else {
                                           /* single si i.e. no sched mask */
                                           si = (struct dn_sch_inst *) fs->sched->siht;
                                           if (si && fs->aqmfp && fs->aqmfp->cleanup)
                                                   fs->aqmfp->cleanup((struct dn_queue *) (si+1));
                           }
                   } 
           }
   
           /* clean up AQM status for all queues for DN_MULTIQUEUE sched*/
           if (fs->sched && fs->sched->fp->flags & DN_MULTIQUEUE && fs->qht) {
                           if (fs->fs.flags & DN_QHT_HASH)
                                   dn_ht_scan(fs->qht, q_cleanup_q, NULL);
                           else
                                   fs->aqmfp->cleanup((struct dn_queue *)(fs->qht));
           }
   
           /* deconfig AQM */
           if(fs->aqmcfg && fs->aqmfp && fs->aqmfp->deconfig)
                   fs->aqmfp->deconfig(fs);
   }
   #endif
   
   /*
    * detach flowset from its current scheduler. Flags as follows:
    * DN_DETACH removes from the fsk_list
    * DN_DESTROY deletes individual queues
    * DN_DELETE_FS destroys the flowset (otherwise goes in unlinked).
    */
   static void
   fsk_detach(struct dn_fsk *fs, int flags)
   {
           if (flags & DN_DELETE_FS)
                   flags |= DN_DESTROY;
           ND("fs %d from sched %d flags %s %s %s",
                   fs->fs.fs_nr, fs->fs.sched_nr,
                   (flags & DN_DELETE_FS) ? "DEL_FS":"",
                   (flags & DN_DESTROY) ? "DEL":"",
                   (flags & DN_DETACH) ? "DET":"");
           if (flags & DN_DETACH) { /* detach from the list */
                   struct dn_fsk_head *h;
                   h = fs->sched ? &fs->sched->fsk_list : &V_dn_cfg.fsu;
                   SLIST_REMOVE(h, fs, dn_fsk, sch_chain);
           }
           /* Free the RED parameters, they will be recomputed on
            * subsequent attach if needed.
            */
           free(fs->w_q_lookup, M_DUMMYNET);
           fs->w_q_lookup = NULL;
           qht_delete(fs, flags);
   #ifdef NEW_AQM
           aqm_cleanup_deconfig_fs(fs);
   #endif
   
           if (fs->sched && fs->sched->fp->free_fsk)
                   fs->sched->fp->free_fsk(fs);
           fs->sched = NULL;
           if (flags & DN_DELETE_FS) {
                   bzero(fs, sizeof(*fs)); /* safety */
                   free(fs, M_DUMMYNET);
                   V_dn_cfg.fsk_count--;
           } else {
                   SLIST_INSERT_HEAD(&V_dn_cfg.fsu, fs, sch_chain);
           }
   }
   
   /*
    * Detach or destroy all flowsets in a list.
    * flags specifies what to do:
    * DN_DESTROY:  flush all queues
    * DN_DELETE_FS:        DN_DESTROY + destroy flowset
    *      DN_DELETE_FS implies DN_DESTROY
    */
   static void
   fsk_detach_list(struct dn_fsk_head *h, int flags)
   {
           struct dn_fsk *fs;
           int n __unused = 0; /* only for stats */
   
           ND("head %p flags %x", h, flags);
           while ((fs = SLIST_FIRST(h))) {
                   SLIST_REMOVE_HEAD(h, sch_chain);
                   n++;
                   fsk_detach(fs, flags);
           }
           ND("done %d flowsets", n);
   }
   
   /*
    * called on 'queue X delete' -- removes the flowset from fshash,
    * deletes all queues for the flowset, and removes the flowset.
    */
   static int
   delete_fs(int i, int locked)
   {
           struct dn_fsk *fs;
           int err = 0;
   
           if (!locked)
                   DN_BH_WLOCK();
           fs = dn_ht_find(V_dn_cfg.fshash, i, DNHT_REMOVE, NULL);
           ND("fs %d found %p", i, fs);
           if (fs) {
                   fsk_detach(fs, DN_DETACH | DN_DELETE_FS);
                   err = 0;
           } else
                   err = EINVAL;
           if (!locked)
                   DN_BH_WUNLOCK();
           return err;
   }
   
   /*----- end of flowset hashtable support -------------*/
   
   /*------------------------------------------------------------
    * Scheduler hash. When searching by index we pass sched_nr,
    * otherwise we pass struct dn_sch * which is the first field in
    * struct dn_schk so we can cast between the two. We use this trick
    * because in the create phase (but it should be fixed).
    */
   static uint32_t
   schk_hash(uintptr_t key, int flags, void *_arg)
   {
           uint32_t i = !(flags & DNHT_KEY_IS_OBJ) ? key :
                   ((struct dn_schk *)key)->sch.sched_nr;
           return ( (i>>8)^(i>>4)^i );
   }
   
   static int
   schk_match(void *obj, uintptr_t key, int flags, void *_arg)
   {
           struct dn_schk *s = (struct dn_schk *)obj;
           int i = !(flags & DNHT_KEY_IS_OBJ) ? key :
                   ((struct dn_schk *)key)->sch.sched_nr;
           return (s->sch.sched_nr == i);
   }
   
   /*
    * Create the entry and intialize with the sched hash if needed.
    * Leave s->fp unset so we can tell whether a dn_ht_find() returns
    * a new object or a previously existing one.
    */
   static void *
   schk_new(uintptr_t key, int flags, void *arg)
   {
           struct schk_new_arg *a = arg;
           struct dn_schk *s;
           int l = sizeof(*s) +a->fp->schk_datalen;
   
           s = malloc(l, M_DUMMYNET, M_NOWAIT | M_ZERO);
           if (s == NULL)
                   return NULL;
           set_oid(&s->link.oid, DN_LINK, sizeof(s->link));
           s->sch = *a->sch; // copy initial values
           s->link.link_nr = s->sch.sched_nr;
           SLIST_INIT(&s->fsk_list);
           /* initialize the hash table or create the single instance */
           s->fp = a->fp;  /* si_new needs this */
           s->drain_bucket = 0;
           if (s->sch.flags & DN_HAVE_MASK) {
                   s->siht = dn_ht_init(NULL, s->sch.buckets,
                           offsetof(struct dn_sch_inst, si_next),
                           si_hash, si_match, si_new);
                   if (s->siht == NULL) {
                           free(s, M_DUMMYNET);
                           return NULL;
                   }
           }
           s->fp = NULL;   /* mark as a new scheduler */
           V_dn_cfg.schk_count++;
           return s;
   }
   
   /*
    * Callback for sched delete. Notify all attached flowsets to
    * detach from the scheduler, destroy the internal flowset, and
    * all instances. The scheduler goes away too.
    * arg is 0 (only detach flowsets and destroy instances)
    * DN_DESTROY (detach & delete queues, delete schk)
    * or DN_DELETE_FS (delete queues and flowsets, delete schk)
    */
   static int
   schk_delete_cb(void *obj, void *arg)
   {
           struct dn_schk *s = obj;
   #if 0
           int a = (int)arg;
           ND("sched %d arg %s%s",
                   s->sch.sched_nr,
                   a&DN_DESTROY ? "DEL ":"",
                   a&DN_DELETE_FS ? "DEL_FS":"");
   #endif
           fsk_detach_list(&s->fsk_list, arg ? DN_DESTROY : 0);
           /* no more flowset pointing to us now */
           if (s->sch.flags & DN_HAVE_MASK) {
                   dn_ht_scan(s->siht, si_destroy, NULL);
                   dn_ht_free(s->siht, 0);
           } else if (s->siht)
                   si_destroy(s->siht, NULL);
   
           free(s->profile, M_DUMMYNET);
           s->profile = NULL;
           s->siht = NULL;
           if (s->fp->destroy)
                   s->fp->destroy(s);
           bzero(s, sizeof(*s));   // safety
           free(obj, M_DUMMYNET);
           V_dn_cfg.schk_count--;
           return DNHT_SCAN_DEL;
   }
   
   /*
    * called on a 'sched X delete' command. Deletes a single scheduler.
    * This is done by removing from the schedhash, unlinking all
    * flowsets and deleting their traffic.
    */
   static int
   delete_schk(int i)
   {
           struct dn_schk *s;
   
           s = dn_ht_find(V_dn_cfg.schedhash, i, DNHT_REMOVE, NULL);
           ND("%d %p", i, s);
           if (!s)
                   return EINVAL;
           delete_fs(i + DN_MAX_ID, 1); /* first delete internal fs */
           /* then detach flowsets, delete traffic */
           schk_delete_cb(s, (void*)(uintptr_t)DN_DESTROY);
           return 0;
   }
   /*--- end of schk hashtable support ---*/
   
   static int
   copy_obj(char **start, char *end, void *_o, const char *msg, int i)
   {
           struct dn_id o;
           union {
                   struct dn_link l;
                   struct dn_schk s;
           } dn;
           int have = end - *start;
   
           memcpy(&o, _o, sizeof(o));
           if (have < o.len || o.len == 0 || o.type == 0) {
                   D("(WARN) type %d %s %d have %d need %d",
                       o.type, msg, i, have, o.len);
                   return 1;
           }
           ND("type %d %s %d len %d", o.type, msg, i, o.len);
           if (o.type == DN_LINK) {
                   memcpy(&dn.l, _o, sizeof(dn.l));
                   /* Adjust burst parameter for link */
                   dn.l.burst = div64(dn.l.burst, 8 * hz);
                   dn.l.delay = dn.l.delay * 1000 / hz;
                   memcpy(*start, &dn.l, sizeof(dn.l));
           } else if (o.type == DN_SCH) {
                   /* Set dn.s.sch.oid.id to the number of instances */
                   memcpy(&dn.s, _o, sizeof(dn.s));
                   dn.s.sch.oid.id = (dn.s.sch.flags & DN_HAVE_MASK) ?
                       dn_ht_entries(dn.s.siht) : (dn.s.siht ? 1 : 0);
                   memcpy(*start, &dn.s, sizeof(dn.s));
           } else
                   memcpy(*start, _o, o.len);
           *start += o.len;
           return 0;
   }
   
   /* Specific function to copy a queue.
    * Copies only the user-visible part of a queue (which is in
    * a struct dn_flow), and sets len accordingly.
    */
   static int
   copy_obj_q(char **start, char *end, void *_o, const char *msg, int i)
   {
           struct dn_id *o = _o;
          int have = end - *start;
          int len = sizeof(struct dn_flow); /* see above comment */
  
          if (have < len || o->len == 0 || o->type != DN_QUEUE) {
                  D("ERROR type %d %s %d have %d need %d",
                          o->type, msg, i, have, len);
                  return 1;
          }
          ND("type %d %s %d len %d", o->type, msg, i, len);
          memcpy(*start, _o, len);
          ((struct dn_id*)(*start))->len = len;
          *start += len;
          return 0;
  }
  
  static int
  copy_q_cb(void *obj, void *arg)
  {
          struct dn_queue *q = obj;
          struct copy_args *a = arg;
          struct dn_flow *ni = (struct dn_flow *)(*a->start);
          if (copy_obj_q(a->start, a->end, &q->ni, "queue", -1))
                  return DNHT_SCAN_END;
          ni->oid.type = DN_FLOW; /* override the DN_QUEUE */
          ni->oid.id = si_hash((uintptr_t)&ni->fid, 0, NULL);
          return 0;
  }
  
  static int
  copy_q(struct copy_args *a, struct dn_fsk *fs, int flags)
  {
          if (!fs->qht)
                  return 0;
          if (fs->fs.flags & DN_QHT_HASH)
                  dn_ht_scan(fs->qht, copy_q_cb, a);
          else
                  copy_q_cb(fs->qht, a);
          return 0;
  }
  
  /*
   * This routine only copies the initial part of a profile ? XXX
   */
  static int
  copy_profile(struct copy_args *a, struct dn_profile *p)
  {
          int have = a->end - *a->start;
          /* XXX here we check for max length */
          int profile_len = sizeof(struct dn_profile) - 
                  ED_MAX_SAMPLES_NO*sizeof(int);
  
          if (p == NULL)
                  return 0;
          if (have < profile_len) {
                  D("error have %d need %d", have, profile_len);
                  return 1;
          }
          memcpy(*a->start, p, profile_len);
          ((struct dn_id *)(*a->start))->len = profile_len;
          *a->start += profile_len;
          return 0;
  }
  
  static int
  copy_flowset(struct copy_args *a, struct dn_fsk *fs, int flags)
  {
          struct dn_fs *ufs = (struct dn_fs *)(*a->start);
          if (!fs)
                  return 0;
          ND("flowset %d", fs->fs.fs_nr);
          if (copy_obj(a->start, a->end, &fs->fs, "flowset", fs->fs.fs_nr))
                  return DNHT_SCAN_END;
          ufs->oid.id = (fs->fs.flags & DN_QHT_HASH) ?
                  dn_ht_entries(fs->qht) : (fs->qht ? 1 : 0);
          if (flags) {    /* copy queues */
                  copy_q(a, fs, 0);
          }
          return 0;
  }
  
  static int
  copy_si_cb(void *obj, void *arg)
  {
          struct dn_sch_inst *si = obj;
          struct copy_args *a = arg;
          struct dn_flow *ni = (struct dn_flow *)(*a->start);
          if (copy_obj(a->start, a->end, &si->ni, "inst",
                          si->sched->sch.sched_nr))
                  return DNHT_SCAN_END;
          ni->oid.type = DN_FLOW; /* override the DN_SCH_I */
          ni->oid.id = si_hash((uintptr_t)si, DNHT_KEY_IS_OBJ, NULL);
          return 0;
  }
  
  static int
  copy_si(struct copy_args *a, struct dn_schk *s, int flags)
  {
          if (s->sch.flags & DN_HAVE_MASK)
                  dn_ht_scan(s->siht, copy_si_cb, a);
          else if (s->siht)
                  copy_si_cb(s->siht, a);
          return 0;
  }
  
  /*
   * compute a list of children of a scheduler and copy up
   */
  static int
  copy_fsk_list(struct copy_args *a, struct dn_schk *s, int flags)
  {
          struct dn_fsk *fs;
          struct dn_id *o;
          uint32_t *p;
  
          int n = 0, space = sizeof(*o);
          SLIST_FOREACH(fs, &s->fsk_list, sch_chain) {
                  if (fs->fs.fs_nr < DN_MAX_ID)
                          n++;
          }
          space += n * sizeof(uint32_t);
          DX(3, "sched %d has %d flowsets", s->sch.sched_nr, n);
          if (a->end - *(a->start) < space)
                  return DNHT_SCAN_END;
          o = (struct dn_id *)(*(a->start));
          o->len = space;
          *a->start += o->len;
          o->type = DN_TEXT;
          p = (uint32_t *)(o+1);
          SLIST_FOREACH(fs, &s->fsk_list, sch_chain)
                  if (fs->fs.fs_nr < DN_MAX_ID)
                          *p++ = fs->fs.fs_nr;
          return 0;
  }
  
  static int
  copy_data_helper(void *_o, void *_arg)
  {
          struct copy_args *a = _arg;
          uint32_t *r = a->extra->r; /* start of first range */
          uint32_t *lim;  /* first invalid pointer */
          int n;
  
          lim = (uint32_t *)((char *)(a->extra) + a->extra->o.len);
  
          if (a->type == DN_LINK || a->type == DN_SCH) {
                  /* pipe|sched show, we receive a dn_schk */
                  struct dn_schk *s = _o;
  
                  n = s->sch.sched_nr;
                  if (a->type == DN_SCH && n >= DN_MAX_ID)
                          return 0;       /* not a scheduler */
                  if (a->type == DN_LINK && n <= DN_MAX_ID)
                      return 0;   /* not a pipe */
  
                  /* see if the object is within one of our ranges */
                  for (;r < lim; r += 2) {
                          if (n < r[0] || n > r[1])
                                  continue;
                          /* Found a valid entry, copy and we are done */
                          if (a->flags & DN_C_LINK) {
                                  if (copy_obj(a->start, a->end,
                                      &s->link, "link", n))
                                          return DNHT_SCAN_END;
                                  if (copy_profile(a, s->profile))
                                          return DNHT_SCAN_END;
                                  if (copy_flowset(a, s->fs, 0))
                                          return DNHT_SCAN_END;
                          }
                          if (a->flags & DN_C_SCH) {
                                  if (copy_obj(a->start, a->end,
                                      &s->sch, "sched", n))
                                          return DNHT_SCAN_END;
                                  /* list all attached flowsets */
                                  if (copy_fsk_list(a, s, 0))
                                          return DNHT_SCAN_END;
                          }
                          if (a->flags & DN_C_FLOW)
                                  copy_si(a, s, 0);
                          break;
                  }
          } else if (a->type == DN_FS) {
                  /* queue show, skip internal flowsets */
                  struct dn_fsk *fs = _o;
  
                  n = fs->fs.fs_nr;
                  if (n >= DN_MAX_ID)
                          return 0;
                  /* see if the object is within one of our ranges */
                  for (;r < lim; r += 2) {
                          if (n < r[0] || n > r[1])
                                  continue;
                          if (copy_flowset(a, fs, 0))
                                  return DNHT_SCAN_END;
                          copy_q(a, fs, 0);
                          break; /* we are done */
                  }
          }
          return 0;
  }
  
  static inline struct dn_schk *
  locate_scheduler(int i)
  {
          return dn_ht_find(V_dn_cfg.schedhash, i, 0, NULL);
  }
  
  /*
   * red parameters are in fixed point arithmetic.
   */
  static int
  config_red(struct dn_fsk *fs)
  {
          int64_t s, idle, weight, w0;
          int t, i;
  
          fs->w_q = fs->fs.w_q;
          fs->max_p = fs->fs.max_p;
          ND("called");
          /* Doing stuff that was in userland */
          i = fs->sched->link.bandwidth;
          s = (i <= 0) ? 0 :
                  hz * V_dn_cfg.red_avg_pkt_size * 8 * SCALE(1) / i;
  
          idle = div64((s * 3) , fs->w_q); /* s, fs->w_q scaled; idle not scaled */
          fs->lookup_step = div64(idle , V_dn_cfg.red_lookup_depth);
          /* fs->lookup_step not scaled, */
          if (!fs->lookup_step)
                  fs->lookup_step = 1;
          w0 = weight = SCALE(1) - fs->w_q; //fs->w_q scaled
  
          for (t = fs->lookup_step; t > 1; --t)
                  weight = SCALE_MUL(weight, w0);
          fs->lookup_weight = (int)(weight); // scaled
  
          /* Now doing stuff that was in kerneland */
          fs->min_th = SCALE(fs->fs.min_th);
          fs->max_th = SCALE(fs->fs.max_th);
  
          if (fs->fs.max_th == fs->fs.min_th)
                  fs->c_1 = fs->max_p;
          else
                  fs->c_1 = SCALE((int64_t)(fs->max_p)) / (fs->fs.max_th - fs->fs.min_th);
          fs->c_2 = SCALE_MUL(fs->c_1, SCALE(fs->fs.min_th));
  
          if (fs->fs.flags & DN_IS_GENTLE_RED) {
                  fs->c_3 = (SCALE(1) - fs->max_p) / fs->fs.max_th;
                  fs->c_4 = SCALE(1) - 2 * fs->max_p;
          }
  
          /* If the lookup table already exist, free and create it again. */
          free(fs->w_q_lookup, M_DUMMYNET);
          fs->w_q_lookup = NULL;
          if (V_dn_cfg.red_lookup_depth == 0) {
                  printf("\ndummynet: net.inet.ip.dummynet.red_lookup_depth"
                      "must be > 0\n");
                  fs->fs.flags &= ~DN_IS_RED;
                  fs->fs.flags &= ~DN_IS_GENTLE_RED;
                  return (EINVAL);
          }
          fs->lookup_depth = V_dn_cfg.red_lookup_depth;
          fs->w_q_lookup = (u_int *)malloc(fs->lookup_depth * sizeof(int),
              M_DUMMYNET, M_NOWAIT);
          if (fs->w_q_lookup == NULL) {
                  printf("dummynet: sorry, cannot allocate red lookup table\n");
                  fs->fs.flags &= ~DN_IS_RED;
                  fs->fs.flags &= ~DN_IS_GENTLE_RED;
                  return(ENOSPC);
          }
  
          /* Fill the lookup table with (1 - w_q)^x */
          fs->w_q_lookup[0] = SCALE(1) - fs->w_q;
  
          for (i = 1; i < fs->lookup_depth; i++)
                  fs->w_q_lookup[i] =
                      SCALE_MUL(fs->w_q_lookup[i - 1], fs->lookup_weight);
  
          if (V_dn_cfg.red_avg_pkt_size < 1)
                  V_dn_cfg.red_avg_pkt_size = 512;
          fs->avg_pkt_size = V_dn_cfg.red_avg_pkt_size;
          if (V_dn_cfg.red_max_pkt_size < 1)
                  V_dn_cfg.red_max_pkt_size = 1500;
          fs->max_pkt_size = V_dn_cfg.red_max_pkt_size;
          ND("exit");
          return 0;
  }
  
  /* Scan all flowset attached to this scheduler and update red */
  static void
  update_red(struct dn_schk *s)
  {
          struct dn_fsk *fs;
          SLIST_FOREACH(fs, &s->fsk_list, sch_chain) {
                  if (fs && (fs->fs.flags & DN_IS_RED))
                          config_red(fs);
          }
  }
  
  /* attach flowset to scheduler s, possibly requeue */
  static void
  fsk_attach(struct dn_fsk *fs, struct dn_schk *s)
  {
          ND("remove fs %d from fsunlinked, link to sched %d",
                  fs->fs.fs_nr, s->sch.sched_nr);
          SLIST_REMOVE(&V_dn_cfg.fsu, fs, dn_fsk, sch_chain);
          fs->sched = s;
          SLIST_INSERT_HEAD(&s->fsk_list, fs, sch_chain);
          if (s->fp->new_fsk)
                  s->fp->new_fsk(fs);
          /* XXX compute fsk_mask */
          fs->fsk_mask = fs->fs.flow_mask;
          if (fs->sched->sch.flags & DN_HAVE_MASK)
                  flow_id_or(&fs->sched->sch.sched_mask, &fs->fsk_mask);
          if (fs->qht) {
                  /*
                   * we must drain qht according to the old
                   * type, and reinsert according to the new one.
                   * The requeue is complex -- in general we need to
                   * reclassify every single packet.
                   * For the time being, let's hope qht is never set
                   * when we reach this point.
                   */
                  D("XXX TODO requeue from fs %d to sch %d",
                          fs->fs.fs_nr, s->sch.sched_nr);
                  fs->qht = NULL;
          }
          /* set the new type for qht */
          if (nonzero_mask(&fs->fsk_mask))
                  fs->fs.flags |= DN_QHT_HASH;
          else
                  fs->fs.flags &= ~DN_QHT_HASH;
  
          /* XXX config_red() can fail... */
          if (fs->fs.flags & DN_IS_RED)
                  config_red(fs);
  }
  
  /* update all flowsets which may refer to this scheduler */
  static void
  update_fs(struct dn_schk *s)
  {
          struct dn_fsk *fs, *tmp;
  
          SLIST_FOREACH_SAFE(fs, &V_dn_cfg.fsu, sch_chain, tmp) {
                  if (s->sch.sched_nr != fs->fs.sched_nr) {
                          D("fs %d for sch %d not %d still unlinked",
                                  fs->fs.fs_nr, fs->fs.sched_nr,
                                  s->sch.sched_nr);
                          continue;
                  }
                  fsk_attach(fs, s);
          }
  }
  
  #ifdef NEW_AQM
  /* Retrieve AQM configurations to ipfw userland 
   */
  static int
  get_aqm_parms(struct sockopt *sopt)
  {
          struct dn_extra_parms  *ep;
          struct dn_fsk *fs;
          size_t sopt_valsize;
          int l, err = 0;
  
          sopt_valsize = sopt->sopt_valsize;
          l = sizeof(*ep);
          if (sopt->sopt_valsize < l) {
                  D("bad len sopt->sopt_valsize %d len %d",
                          (int) sopt->sopt_valsize , l);
                  err = EINVAL;
                  return err;
          }
          ep = malloc(l, M_DUMMYNET, M_NOWAIT);
          if(!ep) {
                  err = ENOMEM ;
                  return err;
          }
          do {
                  err = sooptcopyin(sopt, ep, l, l);
                  if(err)
                          break;
                  sopt->sopt_valsize = sopt_valsize;
                  if (ep->oid.len < l) {
                          err = EINVAL;
                          break;
                  }
  
                  fs = dn_ht_find(V_dn_cfg.fshash, ep->nr, 0, NULL);
                  if (!fs) {
                          D("fs %d not found", ep->nr);
                          err = EINVAL;
                          break;
                  }
  
                  if (fs->aqmfp && fs->aqmfp->getconfig) {
                          if(fs->aqmfp->getconfig(fs, ep)) {
                                  D("Error while trying to get AQM params");
                                  err = EINVAL;
                                  break;
                          }
                          ep->oid.len = l;
                          err = sooptcopyout(sopt, ep, l);
                  }
          }while(0);
  
          free(ep, M_DUMMYNET);
          return err;
  }
  
  /* Retrieve AQM configurations to ipfw userland
   */
  static int
  get_sched_parms(struct sockopt *sopt)
  {
          struct dn_extra_parms  *ep;
          struct dn_schk *schk;
          size_t sopt_valsize;
          int l, err = 0;
  
          sopt_valsize = sopt->sopt_valsize;
          l = sizeof(*ep);
          if (sopt->sopt_valsize < l) {
                  D("bad len sopt->sopt_valsize %d len %d",
                          (int) sopt->sopt_valsize , l);
                  err = EINVAL;
                  return err;
          }
          ep = malloc(l, M_DUMMYNET, M_NOWAIT);
          if(!ep) {
                  err = ENOMEM ;
                  return err;
          }
          do {
                  err = sooptcopyin(sopt, ep, l, l);
                  if(err)
                          break;
                  sopt->sopt_valsize = sopt_valsize;
                  if (ep->oid.len < l) {
                          err = EINVAL;
                          break;
                  }
  
                  schk = locate_scheduler(ep->nr);
                  if (!schk) {
                          D("sched %d not found", ep->nr);
                          err = EINVAL;
                          break;
                  }
                  
                  if (schk->fp && schk->fp->getconfig) {
                          if(schk->fp->getconfig(schk, ep)) {
                                  D("Error while trying to get sched params");
                                  err = EINVAL;
                                  break;
                          }
                          ep->oid.len = l;
                          err = sooptcopyout(sopt, ep, l);
                  }
          }while(0);
          free(ep, M_DUMMYNET);
  
          return err;
  }
  
  /* Configure AQM for flowset 'fs'.
   * extra parameters are passed from userland.
   */
  static int
  config_aqm(struct dn_fsk *fs, struct  dn_extra_parms *ep, int busy)
  {
          int err = 0;
  
          NET_EPOCH_ASSERT();
  
          do {
                  /* no configurations */
                  if (!ep) {
                          err = 0;
                          break;
                  }
  
                  /* no AQM for this flowset*/
                  if (!strcmp(ep->name,"")) {
                          err = 0;
                          break;
                  }
                  if (ep->oid.len < sizeof(*ep)) {
                          D("short aqm len %d", ep->oid.len);
                                  err = EINVAL;
                                  break;
                  }
  
                  if (busy) {
                          D("Unable to configure flowset, flowset busy!");
                          err = EINVAL;
                          break;
                  }
  
                  /* deconfigure old aqm if exist */
                  if (fs->aqmcfg && fs->aqmfp && fs->aqmfp->deconfig) {
                          aqm_cleanup_deconfig_fs(fs);
                  }
  
                  if (!(fs->aqmfp = find_aqm_type(0, ep->name))) {
                          D("AQM functions not found for type %s!", ep->name);
                          fs->fs.flags &= ~DN_IS_AQM;
                          err = EINVAL;
                          break;
                  } else
                          fs->fs.flags |= DN_IS_AQM;
  
                  if (ep->oid.subtype != DN_AQM_PARAMS) {
                                  D("Wrong subtype");
                                  err = EINVAL;
                                  break;
                  }
  
                  if (fs->aqmfp->config) {
                          err = fs->aqmfp->config(fs, ep, ep->oid.len);
                          if (err) {
                                          D("Unable to configure AQM for FS %d", fs->fs.fs_nr );
                                          fs->fs.flags &= ~DN_IS_AQM;
                                          fs->aqmfp = NULL;
                                          break;
                          }
                  }
          } while(0);
  
          return err;
  }
  #endif
  
  /*
   * Configuration -- to preserve backward compatibility we use
   * the following scheme (N is 65536)
   *      NUMBER          SCHED   LINK    FLOWSET
   *         1 ..  N-1    (1)WFQ  (2)WFQ  (3)queue
   *       N+1 .. 2N-1    (4)FIFO (5)FIFO (6)FIFO for sched 1..N-1
   *      2N+1 .. 3N-1    --      --      (7)FIFO for sched N+1..2N-1
   *
   * "pipe i config" configures #1, #2 and #3
   * "sched i config" configures #1 and possibly #6
   * "queue i config" configures #3
   * #1 is configured with 'pipe i config' or 'sched i config'
   * #2 is configured with 'pipe i config', and created if not
   *      existing with 'sched i config'
   * #3 is configured with 'queue i config'
   * #4 is automatically configured after #1, can only be FIFO
   * #5 is automatically configured after #2
   * #6 is automatically created when #1 is !MULTIQUEUE,
   *      and can be updated.
   * #7 is automatically configured after #2
   */
  
  /*
   * configure a link (and its FIFO instance)
   */
  static int
  config_link(struct dn_link *p, struct dn_id *arg)
  {
          int i;
  
          if (p->oid.len != sizeof(*p)) {
                  D("invalid pipe len %d", p->oid.len);
                  return EINVAL;
          }
          i = p->link_nr;
          if (i <= 0 || i >= DN_MAX_ID)
                  return EINVAL;
          /*
           * The config program passes parameters as follows:
           * bw = bits/second (0 means no limits),
           * delay = ms, must be translated into ticks.
           * qsize = slots/bytes
           * burst ???
           */
          p->delay = (p->delay * hz) / 1000;
          /* Scale burst size: bytes -> bits * hz */
          p->burst *= 8 * hz;
  
          DN_BH_WLOCK();
          /* do it twice, base link and FIFO link */
          for (; i < 2*DN_MAX_ID; i += DN_MAX_ID) {
              struct dn_schk *s = locate_scheduler(i);
              if (s == NULL) {
                  DN_BH_WUNLOCK();
                  D("sched %d not found", i);
                  return EINVAL;
              }
              /* remove profile if exists */
              free(s->profile, M_DUMMYNET);
              s->profile = NULL;
  
              /* copy all parameters */
              s->link.oid = p->oid;
              s->link.link_nr = i;
              s->link.delay = p->delay;
              if (s->link.bandwidth != p->bandwidth) {
                  /* XXX bandwidth changes, need to update red params */
              s->link.bandwidth = p->bandwidth;
                  update_red(s);
              }
              s->link.burst = p->burst;
              schk_reset_credit(s);
          }
          V_dn_cfg.id++;
          DN_BH_WUNLOCK();
          return 0;
  }
  
  /*
   * configure a flowset. Can be called from inside with locked=1,
   */
  static struct dn_fsk *
  config_fs(struct dn_fs *nfs, struct dn_id *arg, int locked)
  {
          int i;
          struct dn_fsk *fs;
  #ifdef NEW_AQM
          struct dn_extra_parms *ep;
  #endif
  
          if (nfs->oid.len != sizeof(*nfs)) {
                  D("invalid flowset len %d", nfs->oid.len);
                  return NULL;
          }
          i = nfs->fs_nr;
          if (i <= 0 || i >= 3*DN_MAX_ID)
                  return NULL;
  #ifdef NEW_AQM
          ep = NULL;
          if (arg != NULL) {
                  ep = malloc(sizeof(*ep), M_TEMP, M_NOWAIT);
                  if (ep == NULL)
                          return (NULL);
                  memcpy(ep, arg, sizeof(*ep));
          }
  #endif
          ND("flowset %d", i);
          /* XXX other sanity checks */
          if (nfs->flags & DN_QSIZE_BYTES) {
                  ipdn_bound_var(&nfs->qsize, 16384,
                      1500, V_dn_cfg.byte_limit, NULL); // "queue byte size");
          } else {
                  ipdn_bound_var(&nfs->qsize, 50,
                      1, V_dn_cfg.slot_limit, NULL); // "queue slot size");
          }
          if (nfs->flags & DN_HAVE_MASK) {
                  /* make sure we have some buckets */
                  ipdn_bound_var((int *)&nfs->buckets, V_dn_cfg.hash_size,
                          1, V_dn_cfg.max_hash_size, "flowset buckets");
          } else {
                  nfs->buckets = 1;       /* we only need 1 */
          }
          if (!locked)
                  DN_BH_WLOCK();
          do { /* exit with break when done */
              struct dn_schk *s;
              int flags = nfs->sched_nr ? DNHT_INSERT : 0;
              int j;
              int oldc = V_dn_cfg.fsk_count;
              fs = dn_ht_find(V_dn_cfg.fshash, i, flags, NULL);
              if (fs == NULL) {
                  D("missing sched for flowset %d", i);
                  break;
              }
              /* grab some defaults from the existing one */
              if (nfs->sched_nr == 0) /* reuse */
                  nfs->sched_nr = fs->fs.sched_nr;
              for (j = 0; j < sizeof(nfs->par)/sizeof(nfs->par[0]); j++) {
                  if (nfs->par[j] == -1) /* reuse */
                      nfs->par[j] = fs->fs.par[j];
              }
              if (bcmp(&fs->fs, nfs, sizeof(*nfs)) == 0) {
                  ND("flowset %d unchanged", i);
  #ifdef NEW_AQM
                  if (ep != NULL) {
                          /*
                           * Reconfigure AQM as the parameters can be changed.
                           * We consider the flowset as busy if it has scheduler
                           * instance(s).
                           */ 
                          s = locate_scheduler(nfs->sched_nr);
                          config_aqm(fs, ep, s != NULL && s->siht != NULL);
                  }
  #endif
                  break; /* no change, nothing to do */
              }
              if (oldc != V_dn_cfg.fsk_count)     /* new item */
                  V_dn_cfg.id++;
              s = locate_scheduler(nfs->sched_nr);
              /* detach from old scheduler if needed, preserving
               * queues if we need to reattach. Then update the
               * configuration, and possibly attach to the new sched.
               */
              DX(2, "fs %d changed sched %d@%p to %d@%p",
                  fs->fs.fs_nr,
                  fs->fs.sched_nr, fs->sched, nfs->sched_nr, s);
              if (fs->sched) {
                  int flags = s ? DN_DETACH : (DN_DETACH | DN_DESTROY);
                  flags |= DN_DESTROY; /* XXX temporary */
                  fsk_detach(fs, flags);
              }
              fs->fs = *nfs; /* copy configuration */
  #ifdef NEW_AQM
                          fs->aqmfp = NULL;
                          if (ep != NULL)
                                  config_aqm(fs, ep, s != NULL &&
                                      s->siht != NULL);
  #endif
              if (s != NULL)
                  fsk_attach(fs, s);
          } while (0);
          if (!locked)
                  DN_BH_WUNLOCK();
  #ifdef NEW_AQM
          free(ep, M_TEMP);
  #endif
          return fs;
  }
  
  /*
   * config/reconfig a scheduler and its FIFO variant.
   * For !MULTIQUEUE schedulers, also set up the flowset.
   *
   * On reconfigurations (detected because s->fp is set),
   * detach existing flowsets preserving traffic, preserve link,
   * and delete the old scheduler creating a new one.
   */
  static int
  config_sched(struct dn_sch *_nsch, struct dn_id *arg)
  {
          struct dn_schk *s;
          struct schk_new_arg a; /* argument for schk_new */
          int i;
          struct dn_link p;       /* copy of oldlink */
          struct dn_profile *pf = NULL;   /* copy of old link profile */
          /* Used to preserv mask parameter */
          struct ipfw_flow_id new_mask;
          int new_buckets = 0;
          int new_flags = 0;
          int pipe_cmd;
          int err = ENOMEM;
  
          NET_EPOCH_ASSERT();
  
          a.sch = _nsch;
          if (a.sch->oid.len != sizeof(*a.sch)) {
                  D("bad sched len %d", a.sch->oid.len);
                  return EINVAL;
          }
          i = a.sch->sched_nr;
          if (i <= 0 || i >= DN_MAX_ID)
                  return EINVAL;
          /* make sure we have some buckets */
          if (a.sch->flags & DN_HAVE_MASK)
                  ipdn_bound_var((int *)&a.sch->buckets, V_dn_cfg.hash_size,
                          1, V_dn_cfg.max_hash_size, "sched buckets");
          /* XXX other sanity checks */
          bzero(&p, sizeof(p));
  
          pipe_cmd = a.sch->flags & DN_PIPE_CMD;
          a.sch->flags &= ~DN_PIPE_CMD; //XXX do it even if is not set?
          if (pipe_cmd) {
                  /* Copy mask parameter */
                  new_mask = a.sch->sched_mask;
                  new_buckets = a.sch->buckets;
                  new_flags = a.sch->flags;
          }
          DN_BH_WLOCK();
  again: /* run twice, for wfq and fifo */
          /*
           * lookup the type. If not supplied, use the previous one
           * or default to WF2Q+. Otherwise, return an error.
           */
          V_dn_cfg.id++;
          a.fp = find_sched_type(a.sch->oid.subtype, a.sch->name);
          if (a.fp != NULL) {
                  /* found. Lookup or create entry */
                  s = dn_ht_find(V_dn_cfg.schedhash, i, DNHT_INSERT, &a);
          } else if (a.sch->oid.subtype == 0 && !a.sch->name[0]) {
                  /* No type. search existing s* or retry with WF2Q+ */
                  s = dn_ht_find(V_dn_cfg.schedhash, i, 0, &a);
                  if (s != NULL) {
                          a.fp = s->fp;
                          /* Scheduler exists, skip to FIFO scheduler 
                           * if command was pipe config...
                           */
                          if (pipe_cmd)
                                  goto next;
                  } else {
                          /* New scheduler, create a wf2q+ with no mask
                           * if command was pipe config...
                           */
                          if (pipe_cmd) {
                                  /* clear mask parameter */
                                  bzero(&a.sch->sched_mask, sizeof(new_mask));
                                  a.sch->buckets = 0;
                                  a.sch->flags &= ~DN_HAVE_MASK;
                          }
                          a.sch->oid.subtype = DN_SCHED_WF2QP;
                          goto again;
                  }
          } else {
                  D("invalid scheduler type %d %s",
                          a.sch->oid.subtype, a.sch->name);
                  err = EINVAL;
                  goto error;
          }
          /* normalize name and subtype */
          a.sch->oid.subtype = a.fp->type;
          bzero(a.sch->name, sizeof(a.sch->name));
          strlcpy(a.sch->name, a.fp->name, sizeof(a.sch->name));
          if (s == NULL) {
                  D("cannot allocate scheduler %d", i);
                  goto error;
          }
          /* restore existing link if any */
          if (p.link_nr) {
                  s->link = p;
                  if (!pf || pf->link_nr != p.link_nr) { /* no saved value */
                          s->profile = NULL; /* XXX maybe not needed */
                  } else {
                          s->profile = malloc(sizeof(struct dn_profile),
                                               M_DUMMYNET, M_NOWAIT | M_ZERO);
                          if (s->profile == NULL) {
                                  D("cannot allocate profile");
                                  goto error; //XXX
                          }
                          memcpy(s->profile, pf, sizeof(*pf));
                  }
          }
          p.link_nr = 0;
          if (s->fp == NULL) {
                  DX(2, "sched %d new type %s", i, a.fp->name);
          } else if (s->fp != a.fp ||
                          bcmp(a.sch, &s->sch, sizeof(*a.sch)) ) {
                  /* already existing. */
                  DX(2, "sched %d type changed from %s to %s",
                          i, s->fp->name, a.fp->name);
                  DX(4, "   type/sub %d/%d -> %d/%d",
                          s->sch.oid.type, s->sch.oid.subtype, 
                          a.sch->oid.type, a.sch->oid.subtype);
                  if (s->link.link_nr == 0)
                          D("XXX WARNING link 0 for sched %d", i);
                  p = s->link;    /* preserve link */
                  if (s->profile) {/* preserve profile */
                          if (!pf)
                                  pf = malloc(sizeof(*pf),
                                      M_DUMMYNET, M_NOWAIT | M_ZERO);
                          if (pf) /* XXX should issue a warning otherwise */
                                  memcpy(pf, s->profile, sizeof(*pf));
                  }
                  /* remove from the hash */
                  dn_ht_find(V_dn_cfg.schedhash, i, DNHT_REMOVE, NULL);
                  /* Detach flowsets, preserve queues. */
                  // schk_delete_cb(s, NULL);
                  // XXX temporarily, kill queues
                  schk_delete_cb(s, (void *)DN_DESTROY);
                  goto again;
          } else {
                  DX(4, "sched %d unchanged type %s", i, a.fp->name);
          }
          /* complete initialization */
          s->sch = *a.sch;
          s->fp = a.fp;
          s->cfg = arg;
          // XXX schk_reset_credit(s);
          /* create the internal flowset if needed,
           * trying to reuse existing ones if available
           */
          if (!(s->fp->flags & DN_MULTIQUEUE) && !s->fs) {
                  s->fs = dn_ht_find(V_dn_cfg.fshash, i, 0, NULL);
                  if (!s->fs) {
                          struct dn_fs fs;
                          bzero(&fs, sizeof(fs));
                          set_oid(&fs.oid, DN_FS, sizeof(fs));
                          fs.fs_nr = i + DN_MAX_ID;
                          fs.sched_nr = i;
                          s->fs = config_fs(&fs, NULL, 1 /* locked */);
                  }
                  if (!s->fs) {
                          schk_delete_cb(s, (void *)DN_DESTROY);
                          D("error creating internal fs for %d", i);
                          goto error;
                  }
          }
          /* call init function after the flowset is created */
          if (s->fp->config)
                  s->fp->config(s);
          update_fs(s);
  next:
          if (i < DN_MAX_ID) { /* now configure the FIFO instance */
                  i += DN_MAX_ID;
                  if (pipe_cmd) {
                          /* Restore mask parameter for FIFO */
                          a.sch->sched_mask = new_mask;
                          a.sch->buckets = new_buckets;
                          a.sch->flags = new_flags;
                  } else {
                          /* sched config shouldn't modify the FIFO scheduler */
                          if (dn_ht_find(V_dn_cfg.schedhash, i, 0, &a) != NULL) {
                                  /* FIFO already exist, don't touch it */
                                  err = 0; /* and this is not an error */
                                  goto error;
                          }
                  }
                  a.sch->sched_nr = i;
                  a.sch->oid.subtype = DN_SCHED_FIFO;
                  bzero(a.sch->name, sizeof(a.sch->name));
                  goto again;
          }
          err = 0;
  error:
          DN_BH_WUNLOCK();
          free(pf, M_DUMMYNET);
          return err;
  }
  
  /*
   * attach a profile to a link
   */
  static int
  config_profile(struct dn_profile *pf, struct dn_id *arg)
  {
          struct dn_schk *s;
          int i, olen, err = 0;
  
          if (pf->oid.len < sizeof(*pf)) {
                  D("short profile len %d", pf->oid.len);
                  return EINVAL;
          }
          i = pf->link_nr;
          if (i <= 0 || i >= DN_MAX_ID)
                  return EINVAL;
          /* XXX other sanity checks */
          DN_BH_WLOCK();
          for (; i < 2*DN_MAX_ID; i += DN_MAX_ID) {
                  s = locate_scheduler(i);
  
                  if (s == NULL) {
                          err = EINVAL;
                          break;
                  }
                  V_dn_cfg.id++;
                  /*
                   * If we had a profile and the new one does not fit,
                   * or it is deleted, then we need to free memory.
                   */
                  if (s->profile && (pf->samples_no == 0 ||
                      s->profile->oid.len < pf->oid.len)) {
                          free(s->profile, M_DUMMYNET);
                          s->profile = NULL;
                  }
                  if (pf->samples_no == 0)
                          continue;
                  /*
                   * new profile, possibly allocate memory
                   * and copy data.
                   */
                  if (s->profile == NULL)
                          s->profile = malloc(pf->oid.len,
                                      M_DUMMYNET, M_NOWAIT | M_ZERO);
                  if (s->profile == NULL) {
                          D("no memory for profile %d", i);
                          err = ENOMEM;
                          break;
                  }
                  /* preserve larger length XXX double check */
                  olen = s->profile->oid.len;
                  if (olen < pf->oid.len)
                          olen = pf->oid.len;
                  memcpy(s->profile, pf, pf->oid.len);
                  s->profile->oid.len = olen;
          }
          DN_BH_WUNLOCK();
          return err;
  }
  
  /*
   * Delete all objects:
   */
  static void
  dummynet_flush(void)
  {
  
          /* delete all schedulers and related links/queues/flowsets */
          dn_ht_scan(V_dn_cfg.schedhash, schk_delete_cb,
                  (void *)(uintptr_t)DN_DELETE_FS);
          /* delete all remaining (unlinked) flowsets */
          DX(4, "still %d unlinked fs", V_dn_cfg.fsk_count);
          dn_ht_free(V_dn_cfg.fshash, DNHT_REMOVE);
          fsk_detach_list(&V_dn_cfg.fsu, DN_DELETE_FS);
          /* Reinitialize system heap... */
          heap_init(&V_dn_cfg.evheap, 16, offsetof(struct dn_id, id));
  }
  
  /*
   * Main handler for configuration. We are guaranteed to be called
   * with an oid which is at least a dn_id.
   * - the first object is the command (config, delete, flush, ...)
   * - config_link must be issued after the corresponding config_sched
   * - parameters (DN_TXT) for an object must precede the object
   *   processed on a config_sched.
   */
  int
  do_config(void *p, size_t l)
  {
          struct dn_id o;
          union {
                  struct dn_profile profile;
                  struct dn_fs fs;
                  struct dn_link link;
                  struct dn_sch sched;
          } *dn;
          struct dn_id *arg;
          uintptr_t a;
          int err, err2, off;
  
          memcpy(&o, p, sizeof(o));
          if (o.id != DN_API_VERSION) {
                  D("invalid api version got %d need %d", o.id, DN_API_VERSION);
                  return EINVAL;
          }
          arg = NULL;
          dn = NULL;
          off = 0;
          while (l >= sizeof(o)) {
                  memcpy(&o, (char *)p + off, sizeof(o));
                  if (o.len < sizeof(o) || l < o.len) {
                          D("bad len o.len %d len %zu", o.len, l);
                          err = EINVAL;
                          break;
                  }
                  l -= o.len;
                  err = 0;
                  switch (o.type) {
                  default:
                          D("cmd %d not implemented", o.type);
                          break;
  
  #ifdef EMULATE_SYSCTL
                  /* sysctl emulation.
                   * if we recognize the command, jump to the correct
                   * handler and return
                   */
                  case DN_SYSCTL_SET:
                          err = kesysctl_emu_set(p, l);
                          return err;
  #endif
  
                  case DN_CMD_CONFIG: /* simply a header */
                          break;
  
                  case DN_CMD_DELETE:
                          /* the argument is in the first uintptr_t after o */
                          if (o.len < sizeof(o) + sizeof(a)) {
                                  err = EINVAL;
                                  break;
                          }
                          memcpy(&a, (char *)p + off + sizeof(o), sizeof(a));
                          switch (o.subtype) {
                          case DN_LINK:
                                  /* delete base and derived schedulers */
                                  DN_BH_WLOCK();
                                  err = delete_schk(a);
                                  err2 = delete_schk(a + DN_MAX_ID);
                                  DN_BH_WUNLOCK();
                                  if (!err)
                                          err = err2;
                                  break;
  
                          default:
                                  D("invalid delete type %d", o.subtype);
                                  err = EINVAL;
                                  break;
  
                          case DN_FS:
                                  err = (a < 1 || a >= DN_MAX_ID) ?
                                      EINVAL : delete_fs(a, 0) ;
                                  break;
                          }
                          break;
  
                  case DN_CMD_FLUSH:
                          DN_BH_WLOCK();
                          dummynet_flush();
                          DN_BH_WUNLOCK();
                          break;
                  case DN_TEXT:   /* store argument of next block */
                          free(arg, M_TEMP);
                          arg = malloc(o.len, M_TEMP, M_NOWAIT);
                          if (arg == NULL) {
                                  err = ENOMEM;
                                  break;
                          }
                          memcpy(arg, (char *)p + off, o.len);
                          break;
                  case DN_LINK:
                          if (dn == NULL)
                                  dn = malloc(sizeof(*dn), M_TEMP, M_NOWAIT);
                          if (dn == NULL) {
                                  err = ENOMEM;
                                  break;
                          }
                          memcpy(&dn->link, (char *)p + off, sizeof(dn->link));
                          err = config_link(&dn->link, arg);
                          break;
                  case DN_PROFILE:
                          if (dn == NULL)
                                  dn = malloc(sizeof(*dn), M_TEMP, M_NOWAIT);
                          if (dn == NULL) {
                                  err = ENOMEM;
                                  break;
                          }
                          memcpy(&dn->profile, (char *)p + off,
                              sizeof(dn->profile));
                          err = config_profile(&dn->profile, arg);
                          break;
                  case DN_SCH:
                          if (dn == NULL)
                                  dn = malloc(sizeof(*dn), M_TEMP, M_NOWAIT);
                          if (dn == NULL) {
                                  err = ENOMEM;
                                  break;
                          }
                          memcpy(&dn->sched, (char *)p + off,
                              sizeof(dn->sched));
                          err = config_sched(&dn->sched, arg);
                          break;
                  case DN_FS:
                          if (dn == NULL)
                                  dn = malloc(sizeof(*dn), M_TEMP, M_NOWAIT);
                          if (dn == NULL) {
                                  err = ENOMEM;
                                  break;
                          }
                          memcpy(&dn->fs, (char *)p + off, sizeof(dn->fs));
                          err = (NULL == config_fs(&dn->fs, arg, 0));
                          break;
                  }
                  if (err != 0)
                          break;
                  off += o.len;
          }
          free(arg, M_TEMP);
          free(dn, M_TEMP);
          return err;
  }
  
  static int
  compute_space(struct dn_id *cmd, struct copy_args *a)
  {
          int x = 0, need = 0;
          int profile_size = sizeof(struct dn_profile) - 
                  ED_MAX_SAMPLES_NO*sizeof(int);
  
          /* NOTE about compute space:
           * NP   = V_dn_cfg.schk_count
           * NSI  = V_dn_cfg.si_count
           * NF   = V_dn_cfg.fsk_count
           * NQ   = V_dn_cfg.queue_count
           * - ipfw pipe show
           *   (NP/2)*(dn_link + dn_sch + dn_id + dn_fs) only half scheduler
           *                             link, scheduler template, flowset
           *                             integrated in scheduler and header
           *                             for flowset list
           *   (NSI)*(dn_flow) all scheduler instance (includes
           *                              the queue instance)
           * - ipfw sched show
           *   (NP/2)*(dn_link + dn_sch + dn_id + dn_fs) only half scheduler
           *                             link, scheduler template, flowset
           *                             integrated in scheduler and header
           *                             for flowset list
           *   (NSI * dn_flow) all scheduler instances
           *   (NF * sizeof(uint_32)) space for flowset list linked to scheduler
           *   (NQ * dn_queue) all queue [XXXfor now not listed]
           * - ipfw queue show
           *   (NF * dn_fs) all flowset
           *   (NQ * dn_queue) all queues
           */
          switch (cmd->subtype) {
          default:
                  return -1;
          /* XXX where do LINK and SCH differ ? */
          /* 'ipfw sched show' could list all queues associated to
           * a scheduler. This feature for now is disabled
           */
          case DN_LINK:   /* pipe show */
                  x = DN_C_LINK | DN_C_SCH | DN_C_FLOW;
                  need += V_dn_cfg.schk_count *
                          (sizeof(struct dn_fs) + profile_size) / 2;
                  need += V_dn_cfg.fsk_count * sizeof(uint32_t);
                  break;
          case DN_SCH:    /* sched show */
                  need += V_dn_cfg.schk_count *
                          (sizeof(struct dn_fs) + profile_size) / 2;
                  need += V_dn_cfg.fsk_count * sizeof(uint32_t);
                  x = DN_C_SCH | DN_C_LINK | DN_C_FLOW;
                  break;
          case DN_FS:     /* queue show */
                  x = DN_C_FS | DN_C_QUEUE;
                  break;
          case DN_GET_COMPAT:     /* compatibility mode */
                  need =  dn_compat_calc_size(); 
                  break;
          }
          a->flags = x;
          if (x & DN_C_SCH) {
                  need += V_dn_cfg.schk_count * sizeof(struct dn_sch) / 2;
                  /* NOT also, each fs might be attached to a sched */
                  need += V_dn_cfg.schk_count * sizeof(struct dn_id) / 2;
          }
          if (x & DN_C_FS)
                  need += V_dn_cfg.fsk_count * sizeof(struct dn_fs);
          if (x & DN_C_LINK) {
                  need += V_dn_cfg.schk_count * sizeof(struct dn_link) / 2;
          }
          /*
           * When exporting a queue to userland, only pass up the
           * struct dn_flow, which is the only visible part.
           */
  
          if (x & DN_C_QUEUE)
                  need += V_dn_cfg.queue_count * sizeof(struct dn_flow);
          if (x & DN_C_FLOW)
                  need += V_dn_cfg.si_count * (sizeof(struct dn_flow));
          return need;
  }
  
  /*
   * If compat != NULL dummynet_get is called in compatibility mode.
   * *compat will be the pointer to the buffer to pass to ipfw
   */
  int
  dummynet_get(struct sockopt *sopt, void **compat)
  {
          int have, i, need, error;
          char *start = NULL, *buf;
          size_t sopt_valsize;
          struct dn_id *cmd;
          struct copy_args a;
          struct copy_range r;
          int l = sizeof(struct dn_id);
  
          bzero(&a, sizeof(a));
          bzero(&r, sizeof(r));
  
          /* save and restore original sopt_valsize around copyin */
          sopt_valsize = sopt->sopt_valsize;
  
          cmd = &r.o;
  
          if (!compat) {
                  /* copy at least an oid, and possibly a full object */
                  error = sooptcopyin(sopt, cmd, sizeof(r), sizeof(*cmd));
                  sopt->sopt_valsize = sopt_valsize;
                  if (error)
                          goto done;
                  l = cmd->len;
  #ifdef EMULATE_SYSCTL
                  /* sysctl emulation. */
                  if (cmd->type == DN_SYSCTL_GET)
                          return kesysctl_emu_get(sopt);
  #endif
                  if (l > sizeof(r)) {
                          /* request larger than default, allocate buffer */
                          cmd = malloc(l,  M_DUMMYNET, M_NOWAIT);
                          if (cmd == NULL) {
                                  error = ENOMEM;
                                  goto done;
                          }
                          error = sooptcopyin(sopt, cmd, l, l);
                          sopt->sopt_valsize = sopt_valsize;
                          if (error)
                                  goto done;
                  }
          } else { /* compatibility */
                  error = 0;
                  cmd->type = DN_CMD_GET;
                  cmd->len = sizeof(struct dn_id);
                  cmd->subtype = DN_GET_COMPAT;
                  // cmd->id = sopt_valsize;
                  D("compatibility mode");
          }
  
  #ifdef NEW_AQM
          /* get AQM params */
          if(cmd->subtype == DN_AQM_PARAMS) {
                  error = get_aqm_parms(sopt);
                  goto done;
          /* get Scheduler params */
          } else if (cmd->subtype == DN_SCH_PARAMS) {
                  error = get_sched_parms(sopt);
                  goto done;
          }
  #endif
  
          a.extra = (struct copy_range *)cmd;
          if (cmd->len == sizeof(*cmd)) { /* no range, create a default */
                  uint32_t *rp = (uint32_t *)(cmd + 1);
                  cmd->len += 2* sizeof(uint32_t);
                  rp[0] = 1;
                  rp[1] = DN_MAX_ID - 1;
                  if (cmd->subtype == DN_LINK) {
                          rp[0] += DN_MAX_ID;
                          rp[1] += DN_MAX_ID;
                  }
          }
          /* Count space (under lock) and allocate (outside lock).
           * Exit with lock held if we manage to get enough buffer.
           * Try a few times then give up.
           */
          for (have = 0, i = 0; i < 10; i++) {
                  DN_BH_WLOCK();
                  need = compute_space(cmd, &a);
  
                  /* if there is a range, ignore value from compute_space() */
                  if (l > sizeof(*cmd))
                          need = sopt_valsize - sizeof(*cmd);
  
                  if (need < 0) {
                          DN_BH_WUNLOCK();
                          error = EINVAL;
                          goto done;
                  }
                  need += sizeof(*cmd);
                  cmd->id = need;
                  if (have >= need)
                          break;
  
                  DN_BH_WUNLOCK();
                  free(start, M_DUMMYNET);
                  start = NULL;
                  if (need > sopt_valsize)
                          break;
  
                  have = need;
                  start = malloc(have, M_DUMMYNET, M_NOWAIT | M_ZERO);
          }
  
          if (start == NULL) {
                  if (compat) {
                          *compat = NULL;
                          error =  1; // XXX
                  } else {
                          error = sooptcopyout(sopt, cmd, sizeof(*cmd));
                  }
                  goto done;
          }
          ND("have %d:%d sched %d, %d:%d links %d, %d:%d flowsets %d, "
                  "%d:%d si %d, %d:%d queues %d",
                  V_dn_cfg.schk_count, sizeof(struct dn_sch), DN_SCH,
                  V_dn_cfg.schk_count, sizeof(struct dn_link), DN_LINK,
                  V_dn_cfg.fsk_count, sizeof(struct dn_fs), DN_FS,
                  V_dn_cfg.si_count, sizeof(struct dn_flow), DN_SCH_I,
                  V_dn_cfg.queue_count, sizeof(struct dn_queue), DN_QUEUE);
          sopt->sopt_valsize = sopt_valsize;
          a.type = cmd->subtype;
  
          if (compat == NULL) {
                  memcpy(start, cmd, sizeof(*cmd));
                  ((struct dn_id*)(start))->len = sizeof(struct dn_id);
                  buf = start + sizeof(*cmd);
          } else
                  buf = start;
          a.start = &buf;
          a.end = start + have;
          /* start copying other objects */
          if (compat) {
                  a.type = DN_COMPAT_PIPE;
                  dn_ht_scan(V_dn_cfg.schedhash, copy_data_helper_compat, &a);
                  a.type = DN_COMPAT_QUEUE;
                  dn_ht_scan(V_dn_cfg.fshash, copy_data_helper_compat, &a);
          } else if (a.type == DN_FS) {
                  dn_ht_scan(V_dn_cfg.fshash, copy_data_helper, &a);
          } else {
                  dn_ht_scan(V_dn_cfg.schedhash, copy_data_helper, &a);
          }
          DN_BH_WUNLOCK();
  
          if (compat) {
                  *compat = start;
                  sopt->sopt_valsize = buf - start;
                  /* free() is done by ip_dummynet_compat() */
                  start = NULL; //XXX hack
          } else {
                  error = sooptcopyout(sopt, start, buf - start);
          }
  done:
          if (cmd != &r.o)
                  free(cmd, M_DUMMYNET);
          free(start, M_DUMMYNET);
          return error;
  }
  
  /* Callback called on scheduler instance to delete it if idle */
  static int
  drain_scheduler_cb(void *_si, void *arg)
  {
          struct dn_sch_inst *si = _si;
  
          if ((si->kflags & DN_ACTIVE) || si->dline.mq.head != NULL)
                  return 0;
  
          if (si->sched->fp->flags & DN_MULTIQUEUE) {
                  if (si->q_count == 0)
                          return si_destroy(si, NULL);
                  else
                          return 0;
          } else { /* !DN_MULTIQUEUE */
                  if ((si+1)->ni.length == 0)
                          return si_destroy(si, NULL);
                  else
                          return 0;
          }
          return 0; /* unreachable */
  }
  
  /* Callback called on scheduler to check if it has instances */
  static int
  drain_scheduler_sch_cb(void *_s, void *arg)
  {
          struct dn_schk *s = _s;
  
          if (s->sch.flags & DN_HAVE_MASK) {
                  dn_ht_scan_bucket(s->siht, &s->drain_bucket,
                                  drain_scheduler_cb, NULL);
                  s->drain_bucket++;
          } else {
                  if (s->siht) {
                          if (drain_scheduler_cb(s->siht, NULL) == DNHT_SCAN_DEL)
                                  s->siht = NULL;
                  }
          }
          return 0;
  }
  
  /* Called every tick, try to delete a 'bucket' of scheduler */
  void
  dn_drain_scheduler(void)
  {
          dn_ht_scan_bucket(V_dn_cfg.schedhash, &V_dn_cfg.drain_sch,
                             drain_scheduler_sch_cb, NULL);
          V_dn_cfg.drain_sch++;
  }
  
  /* Callback called on queue to delete if it is idle */
  static int
  drain_queue_cb(void *_q, void *arg)
  {
          struct dn_queue *q = _q;
  
          if (q->ni.length == 0) {
                  dn_delete_queue(q, DN_DESTROY);
                  return DNHT_SCAN_DEL; /* queue is deleted */
          }
  
          return 0; /* queue isn't deleted */
  }
  
  /* Callback called on flowset used to check if it has queues */
  static int
  drain_queue_fs_cb(void *_fs, void *arg)
  {
          struct dn_fsk *fs = _fs;
  
          if (fs->fs.flags & DN_QHT_HASH) {
                  /* Flowset has a hash table for queues */
                  dn_ht_scan_bucket(fs->qht, &fs->drain_bucket,
                                  drain_queue_cb, NULL);
                  fs->drain_bucket++;
          } else {
                  /* No hash table for this flowset, null the pointer 
                   * if the queue is deleted
                   */
                  if (fs->qht) {
                          if (drain_queue_cb(fs->qht, NULL) == DNHT_SCAN_DEL)
                                  fs->qht = NULL;
                  }
          }
          return 0;
  }
  
  /* Called every tick, try to delete a 'bucket' of queue */
  void
  dn_drain_queue(void)
  {
          /* scan a bucket of flowset */
          dn_ht_scan_bucket(V_dn_cfg.fshash, &V_dn_cfg.drain_fs,
                                 drain_queue_fs_cb, NULL);
          V_dn_cfg.drain_fs++;
  }
  
  /*
   * Handler for the various dummynet socket options
   */
  static int
  ip_dn_ctl(struct sockopt *sopt)
  {
          struct epoch_tracker et;
          void *p = NULL;
          size_t l;
          int error;
  
          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) {
                  error =  securelevel_ge(sopt->sopt_td->td_ucred, 3);
                  if (error)
                          return (error);
          }
  
          NET_EPOCH_ENTER(et);
  
          switch (sopt->sopt_name) {
          default :
                  D("dummynet: unknown option %d", sopt->sopt_name);
                  error = EINVAL;
                  break;
  
          case IP_DUMMYNET_FLUSH:
          case IP_DUMMYNET_CONFIGURE:
          case IP_DUMMYNET_DEL:   /* remove a pipe or queue */
          case IP_DUMMYNET_GET:
                  D("dummynet: compat option %d", sopt->sopt_name);
                  error = ip_dummynet_compat(sopt);
                  break;
  
          case IP_DUMMYNET3:
                  if (sopt->sopt_dir == SOPT_GET) {
                          error = dummynet_get(sopt, NULL);
                          break;
                  }
                  l = sopt->sopt_valsize;
                  if (l < sizeof(struct dn_id) || l > 12000) {
                          D("argument len %zu invalid", l);
                          break;
                  }
                  p = malloc(l, M_TEMP, M_NOWAIT);
                  if (p == NULL) {
                          error = ENOMEM;
                          break;
                  }
                  error = sooptcopyin(sopt, p, l, l);
                  if (error == 0)
                          error = do_config(p, l);
                  break;
          }
  
          free(p, M_TEMP);
  
          NET_EPOCH_EXIT(et);
  
          return error ;
  }
  
  static void
  ip_dn_vnet_init(void)
  {
          if (V_dn_cfg.init_done)
                  return;
  
          /* Set defaults here. MSVC does not accept initializers,
           * and this is also useful for vimages
           */
          /* queue limits */
          V_dn_cfg.slot_limit = 100; /* Foot shooting limit for queues. */
          V_dn_cfg.byte_limit = 1024 * 1024;
          V_dn_cfg.expire = 1;
  
          /* RED parameters */
          V_dn_cfg.red_lookup_depth = 256;        /* default lookup table depth */
          V_dn_cfg.red_avg_pkt_size = 512;        /* default medium packet size */
          V_dn_cfg.red_max_pkt_size = 1500;       /* default max packet size */
  
          /* hash tables */
          V_dn_cfg.max_hash_size = 65536; /* max in the hash tables */
          V_dn_cfg.hash_size = 64;                /* default hash size */
  
          /* create hash tables for schedulers and flowsets.
           * In both we search by key and by pointer.
           */
          V_dn_cfg.schedhash = dn_ht_init(NULL, V_dn_cfg.hash_size,
                  offsetof(struct dn_schk, schk_next),
                  schk_hash, schk_match, schk_new);
          V_dn_cfg.fshash = dn_ht_init(NULL, V_dn_cfg.hash_size,
                  offsetof(struct dn_fsk, fsk_next),
                  fsk_hash, fsk_match, fsk_new);
  
          /* bucket index to drain object */
          V_dn_cfg.drain_fs = 0;
          V_dn_cfg.drain_sch = 0;
  
          heap_init(&V_dn_cfg.evheap, 16, offsetof(struct dn_id, id));
          SLIST_INIT(&V_dn_cfg.fsu);
  
          DN_LOCK_INIT();
  
          /* Initialize curr_time adjustment mechanics. */
          getmicrouptime(&V_dn_cfg.prev_t);
  
          V_dn_cfg.init_done = 1;
  }
  
  static void
  ip_dn_vnet_destroy(void)
  {
          DN_BH_WLOCK();
          dummynet_flush();
          DN_BH_WUNLOCK();
  
          dn_ht_free(V_dn_cfg.schedhash, 0);
          dn_ht_free(V_dn_cfg.fshash, 0);
          heap_free(&V_dn_cfg.evheap);
  
          DN_LOCK_DESTROY();
  }
  
  static void
  ip_dn_init(void)
  {
          if (dn_tasks_started)
                  return;
  
          mtx_init(&sched_mtx, "dn_sched", NULL, MTX_DEF);
  
          dn_tasks_started = 1;
          TASK_INIT(&dn_task, 0, dummynet_task, NULL);
          dn_tq = taskqueue_create_fast("dummynet", M_WAITOK,
              taskqueue_thread_enqueue, &dn_tq);
          taskqueue_start_threads(&dn_tq, 1, PI_NET, "dummynet");
  
          CK_LIST_INIT(&schedlist);
          callout_init(&dn_timeout, 1);
          dn_reschedule();
  }
  
  static void
  ip_dn_destroy(int last)
  {
          /* ensure no more callouts are started */
          dn_gone = 1;
  
          /* check for last */
          if (last) {
                  ND("removing last instance\n");
                  ip_dn_ctl_ptr = NULL;
                  ip_dn_io_ptr = NULL;
          }
  
          callout_drain(&dn_timeout);
          taskqueue_drain(dn_tq, &dn_task);
          taskqueue_free(dn_tq);
  }
  
  static int
  dummynet_modevent(module_t mod, int type, void *data)
  {
  
          if (type == MOD_LOAD) {
                  if (ip_dn_io_ptr) {
                          printf("DUMMYNET already loaded\n");
                          return EEXIST ;
                  }
                  ip_dn_init();
                  ip_dn_ctl_ptr = ip_dn_ctl;
                  ip_dn_io_ptr = dummynet_io;
                  return 0;
          } else if (type == MOD_UNLOAD) {
                  ip_dn_destroy(1 /* last */);
                  return 0;
          } else
                  return EOPNOTSUPP;
  }
  
  /* modevent helpers for the modules */
  static int
  load_dn_sched(struct dn_alg *d)
  {
          struct dn_alg *s;
  
          if (d == NULL)
                  return 1; /* error */
          ip_dn_init();   /* just in case, we need the lock */
  
          /* Check that mandatory funcs exists */
          if (d->enqueue == NULL || d->dequeue == NULL) {
                  D("missing enqueue or dequeue for %s", d->name);
                  return 1;
          }
  
          /* Search if scheduler already exists */
          mtx_lock(&sched_mtx);
          CK_LIST_FOREACH(s, &schedlist, next) {
                  if (strcmp(s->name, d->name) == 0) {
                          D("%s already loaded", d->name);
                          break; /* scheduler already exists */
                  }
          }
          if (s == NULL)
                  CK_LIST_INSERT_HEAD(&schedlist, d, next);
          mtx_unlock(&sched_mtx);
          D("dn_sched %s %sloaded", d->name, s ? "not ":"");
          return s ? 1 : 0;
  }
  
  static int
  unload_dn_sched(struct dn_alg *s)
  {
          struct dn_alg *tmp, *r;
          int err = EINVAL;
  
          ND("called for %s", s->name);
  
          mtx_lock(&sched_mtx);
          CK_LIST_FOREACH_SAFE(r, &schedlist, next, tmp) {
                  if (strcmp(s->name, r->name) != 0)
                          continue;
                  ND("ref_count = %d", r->ref_count);
                  err = (r->ref_count != 0) ? EBUSY : 0;
                  if (err == 0)
                          CK_LIST_REMOVE(r, next);
                  break;
          }
          mtx_unlock(&sched_mtx);
          NET_EPOCH_WAIT();
          D("dn_sched %s %sunloaded", s->name, err ? "not ":"");
          return err;
  }
  
  int
  dn_sched_modevent(module_t mod, int cmd, void *arg)
  {
          struct dn_alg *sch = arg;
  
          if (cmd == MOD_LOAD)
                  return load_dn_sched(sch);
          else if (cmd == MOD_UNLOAD)
                  return unload_dn_sched(sch);
          else
                  return EINVAL;
  }
  
  static moduledata_t dummynet_mod = {
          "dummynet", dummynet_modevent, NULL
  };
  
  #define DN_SI_SUB       SI_SUB_PROTO_FIREWALL
  #define DN_MODEV_ORD    (SI_ORDER_ANY - 128) /* after ipfw */
  DECLARE_MODULE(dummynet, dummynet_mod, DN_SI_SUB, DN_MODEV_ORD);
  MODULE_VERSION(dummynet, 3);
  
  /*
   * Starting up. Done in order after dummynet_modevent() has been called.
   * VNET_SYSINIT is also called for each existing vnet and each new vnet.
   */
  VNET_SYSINIT(vnet_dn_init, DN_SI_SUB, DN_MODEV_ORD+2, ip_dn_vnet_init, NULL);
  
  /*
   * Shutdown handlers up shop. These are done in REVERSE ORDER, but still
   * after dummynet_modevent() has been called. Not called on reboot.
   * VNET_SYSUNINIT is also called for each exiting vnet as it exits.
   * or when the module is unloaded.
   */
  VNET_SYSUNINIT(vnet_dn_uninit, DN_SI_SUB, DN_MODEV_ORD+2, ip_dn_vnet_destroy, NULL);
  
  #ifdef NEW_AQM
  
  /* modevent helpers for the AQM modules */
  static int
  load_dn_aqm(struct dn_aqm *d)
  {
          struct dn_aqm *aqm=NULL;
  
          if (d == NULL)
                  return 1; /* error */
          ip_dn_init();   /* just in case, we need the lock */
  
          /* Check that mandatory funcs exists */
          if (d->enqueue == NULL || d->dequeue == NULL) {
                  D("missing enqueue or dequeue for %s", d->name);
                  return 1;
          }
  
          mtx_lock(&sched_mtx);
  
          /* Search if AQM already exists */
          CK_LIST_FOREACH(aqm, &aqmlist, next) {
                  if (strcmp(aqm->name, d->name) == 0) {
                          D("%s already loaded", d->name);
                          break; /* AQM already exists */
                  }
          }
          if (aqm == NULL)
                  CK_LIST_INSERT_HEAD(&aqmlist, d, next);
  
          mtx_unlock(&sched_mtx);
  
          D("dn_aqm %s %sloaded", d->name, aqm ? "not ":"");
          return aqm ? 1 : 0;
  }
  
  /* Callback to clean up AQM status for queues connected to a flowset
   * and then deconfigure the flowset.
   * This function is called before an AQM module is unloaded
   */
  static int
  fs_cleanup(void *_fs, void *arg)
  {
          struct dn_fsk *fs = _fs;
          uint32_t type = *(uint32_t *)arg;
  
          if (fs->aqmfp && fs->aqmfp->type == type)
                  aqm_cleanup_deconfig_fs(fs);
  
          return 0;
  }
  
  static int
  unload_dn_aqm(struct dn_aqm *aqm)
  {
          struct dn_aqm *tmp, *r;
          int err = EINVAL;
          err = 0;
          ND("called for %s", aqm->name);
  
          /* clean up AQM status and deconfig flowset */
          dn_ht_scan(V_dn_cfg.fshash, fs_cleanup, &aqm->type);
  
          mtx_lock(&sched_mtx);
  
          CK_LIST_FOREACH_SAFE(r, &aqmlist, next, tmp) {
                  if (strcmp(aqm->name, r->name) != 0)
                          continue;
                  ND("ref_count = %d", r->ref_count);
                  err = (r->ref_count != 0 || r->cfg_ref_count != 0) ? EBUSY : 0;
                  if (err == 0)
                          CK_LIST_REMOVE(r, next);
                  break;
          }
  
          mtx_unlock(&sched_mtx);
          NET_EPOCH_WAIT();
  
          D("%s %sunloaded", aqm->name, err ? "not ":"");
          if (err)
                  D("ref_count=%d, cfg_ref_count=%d", r->ref_count, r->cfg_ref_count);
          return err;
  }
  
  int
  dn_aqm_modevent(module_t mod, int cmd, void *arg)
  {
          struct dn_aqm *aqm = arg;
  
          if (cmd == MOD_LOAD)
                  return load_dn_aqm(aqm);
          else if (cmd == MOD_UNLOAD)
                  return unload_dn_aqm(aqm);
          else
                  return EINVAL;
  }
  #endif
  
  /* end of file */

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