MFC r362623:

[FreeBSD/stable/8.git] / sys / netinet / ipfw / ip_dummynet.c

/*-
 * 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/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.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/ipfw/ip_fw_private.h>
#include <netinet/ipfw/dn_heap.h>
#include <netinet/ip_dummynet.h>
#include <netinet/ipfw/ip_dn_private.h>
#include <netinet/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 struct task      dn_task;
static struct taskqueue *dn_tq = NULL;

static void
dummynet(void * __unused unused)
{

        taskqueue_enqueue(dn_tq, &dn_task);
}

void
dn_reschedule(void)
{
        callout_reset(&dn_timeout, 1, dummynet, NULL);
}
/*----- end of callout hooks -----*/

/* Return a scheduler descriptor given the type or name. */
static struct dn_alg *
find_sched_type(int type, char *name)
{
        struct dn_alg *d;

        SLIST_FOREACH(d, &dn_cfg.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)
                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);
        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;

        // 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);
                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;

        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(&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(&dn_cfg.evheap, si);
        if (s->fp->free_sched)
                s->fp->free_sched(si);
        bzero(si, sizeof(*si)); /* safety */
        free(si, M_DUMMYNET);
        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 + (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));
                dn_cfg.fsk_count++;
                fs->drain_bucket = 0;
                SLIST_INSERT_HEAD(&dn_cfg.fsu, fs, sch_chain);
        }
        return fs;
}

/*
 * 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 : &dn_cfg.fsu;
                SLIST_REMOVE(h, fs, dn_fsk, sch_chain);
        }
        /* Free the RED parameters, they will be recomputed on
         * subsequent attach if needed.
         */
        if (fs->w_q_lookup)
                free(fs->w_q_lookup, M_DUMMYNET);
        fs->w_q_lookup = NULL;
        qht_delete(fs, flags);
        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);
                dn_cfg.fsk_count--;
        } else {
                SLIST_INSERT_HEAD(&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 = 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(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 */
        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);
        if (s->profile) {
                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);
        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(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 = _o;
        int have = end - *start;

        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);
        bcopy(_o, *start, o->len);
        if (o->type == DN_LINK) {
                /* Adjust burst parameter for link */
                struct dn_link *l = (struct dn_link *)*start;
                l->burst =  div64(l->burst, 8 * hz);
                l->delay = l->delay * 1000 / hz;
        } else if (o->type == DN_SCH) {
                /* Set id->id to the number of instances */
                struct dn_schk *s = _o;
                struct dn_id *id = (struct dn_id *)(*start);
                id->id = (s->sch.flags & DN_HAVE_MASK) ?
                        dn_ht_entries(s->siht) : (s->siht ? 1 : 0);
        }
        *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);
        bcopy(_o, *start, 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;
        }
        bcopy(p, *a->start, 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(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 * 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 , 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);

        fs->c_1 = 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. */
        if (fs->w_q_lookup) {
                free(fs->w_q_lookup, M_DUMMYNET);
                fs->w_q_lookup = NULL;
        }
        if (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 = 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 (dn_cfg.red_avg_pkt_size < 1)
                dn_cfg.red_avg_pkt_size = 512;
        fs->avg_pkt_size = dn_cfg.red_avg_pkt_size;
        if (dn_cfg.red_max_pkt_size < 1)
                dn_cfg.red_max_pkt_size = 1500;
        fs->max_pkt_size = 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(&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, &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);
        }
}

/*
 * 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 */
            if (s->profile) {
                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);
        }
        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;

        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;
        ND("flowset %d", i);
        /* XXX other sanity checks */
        if (nfs->flags & DN_QSIZE_BYTES) {
                ipdn_bound_var(&nfs->qsize, 16384,
                    1500, dn_cfg.byte_limit, NULL); // "queue byte size");
        } else {
                ipdn_bound_var(&nfs->qsize, 50,
                    1, dn_cfg.slot_limit, NULL); // "queue slot size");
        }
        if (nfs->flags & DN_HAVE_MASK) {
                /* make sure we have some buckets */
                ipdn_bound_var(&nfs->buckets, dn_cfg.hash_size,
                        1, 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 = dn_cfg.fsk_count;
            fs = dn_ht_find(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);
                break; /* no change, nothing to do */
            }
            if (oldc != dn_cfg.fsk_count)       /* new item */
                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 */
            if (s != NULL)
                fsk_attach(fs, s);
        } while (0);
        if (!locked)
                DN_BH_WUNLOCK();
        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;

        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(&a.sch->buckets, dn_cfg.hash_size,
                        1, 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.
         */
        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(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(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
                        }
                        bcopy(pf, s->profile, 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 */
                                bcopy(s->profile, pf, sizeof(*pf));
                }
                /* remove from the hash */
                dn_ht_find(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(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(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();
        if (pf)
                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;
        }
        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;
                bcopy(pf, s->profile, 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(dn_cfg.schedhash, schk_delete_cb,
                (void *)(uintptr_t)DN_DELETE_FS);
        /* delete all remaining (unlinked) flowsets */
        DX(4, "still %d unlinked fs", dn_cfg.fsk_count);
        dn_ht_free(dn_cfg.fshash, DNHT_REMOVE);
        fsk_detach_list(&dn_cfg.fsu, DN_DELETE_FS);
        /* Reinitialize system heap... */
        heap_init(&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 preceed the object
 *   processed on a config_sched.
 */
int
do_config(void *p, int l)
{
        struct dn_id *next, *o;
        int err = 0, err2 = 0;
        struct dn_id *arg = NULL;
        uintptr_t *a;

        o = p;
        if (o->id != DN_API_VERSION) {
                D("invalid api version got %d need %d",
                        o->id, DN_API_VERSION);
                return EINVAL;
        }
        for (; l >= sizeof(*o); o = next) {
                struct dn_id *prev = arg;
                if (o->len < sizeof(*o) || l < o->len) {
                        D("bad len o->len %d len %d", o->len, l);
                        err = EINVAL;
                        break;
                }
                l -= o->len;
                next = (struct dn_id *)((char *)o + 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 */
                        a = (uintptr_t *)(o+1);
                        if (o->len < sizeof(*o) + sizeof(*a)) {
                                err = EINVAL;
                                break;
                        }
                        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 the next block */
                        prev = NULL;
                        arg = o;
                        break;
                case DN_LINK:
                        err = config_link((struct dn_link *)o, arg);
                        break;
                case DN_PROFILE:
                        err = config_profile((struct dn_profile *)o, arg);
                        break;
                case DN_SCH:
                        err = config_sched((struct dn_sch *)o, arg);
                        break;
                case DN_FS:
                        err = (NULL==config_fs((struct dn_fs *)o, arg, 0));
                        break;
                }
                if (prev)
                        arg = NULL;
                if (err != 0)
                        break;
        }
        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   = dn_cfg.schk_count
         * NSI  = dn_cfg.si_count
         * NF   = dn_cfg.fsk_count
         * NQ   = 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 += dn_cfg.schk_count *
                        (sizeof(struct dn_fs) + profile_size) / 2;
                need += dn_cfg.fsk_count * sizeof(uint32_t);
                break;
        case DN_SCH:    /* sched show */
                need += dn_cfg.schk_count *
                        (sizeof(struct dn_fs) + profile_size) / 2;
                need += 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(dn_cfg); 
                break;
        }
        a->flags = x;
        if (x & DN_C_SCH) {
                need += dn_cfg.schk_count * sizeof(struct dn_sch) / 2;
                /* NOT also, each fs might be attached to a sched */
                need += dn_cfg.schk_count * sizeof(struct dn_id) / 2;
        }
        if (x & DN_C_FS)
                need += dn_cfg.fsk_count * sizeof(struct dn_fs);
        if (x & DN_C_LINK) {
                need += 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 += dn_cfg.queue_count * sizeof(struct dn_flow);
        if (x & DN_C_FLOW)
                need += 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_WAITOK);
                        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");
        }
        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();
                if (start)
                        free(start, M_DUMMYNET);
                start = NULL;
                if (need > sopt_valsize)
                        break;

                have = need;
                start = malloc(have, M_DUMMYNET, M_WAITOK | 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",
                dn_cfg.schk_count, sizeof(struct dn_sch), DN_SCH,
                dn_cfg.schk_count, sizeof(struct dn_link), DN_LINK,
                dn_cfg.fsk_count, sizeof(struct dn_fs), DN_FS,
                dn_cfg.si_count, sizeof(struct dn_flow), DN_SCH_I,
                dn_cfg.queue_count, sizeof(struct dn_queue), DN_QUEUE);
        sopt->sopt_valsize = sopt_valsize;
        a.type = cmd->subtype;

        if (compat == NULL) {
                bcopy(cmd, start, 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(dn_cfg.schedhash, copy_data_helper_compat, &a);
                a.type = DN_COMPAT_QUEUE;
                dn_ht_scan(dn_cfg.fshash, copy_data_helper_compat, &a);
        } else if (a.type == DN_FS) {
                dn_ht_scan(dn_cfg.fshash, copy_data_helper, &a);
        } else {
                dn_ht_scan(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 && cmd != &r.o)
                free(cmd, M_DUMMYNET);
        if (start)
                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(dn_cfg.schedhash, &dn_cfg.drain_sch,
                           drain_scheduler_sch_cb, NULL);
        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(dn_cfg.fshash, &dn_cfg.drain_fs,
                               drain_queue_fs_cb, NULL);
        dn_cfg.drain_fs++;
}

/*
 * Handler for the various dummynet socket options
 */
static int
ip_dn_ctl(struct sockopt *sopt)
{
        void *p = NULL;
        int error, l;

        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);
        }

        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 %d invalid", l);
                        break;
                }
                p = malloc(l, M_TEMP, M_WAITOK); // XXX can it fail ?
                error = sooptcopyin(sopt, p, l, l);
                if (error)
                        break ;
                error = do_config(p, l);
                break;
        }

        if (p != NULL)
                free(p, M_TEMP);

        return error ;
}


static void
ip_dn_init(void)
{
        if (dn_cfg.init_done)
                return;
        printf("DUMMYNET %p with IPv6 initialized (100409)\n", curvnet);
        dn_cfg.init_done = 1;
        /* Set defaults here. MSVC does not accept initializers,
         * and this is also useful for vimages
         */
        /* queue limits */
        dn_cfg.slot_limit = 100; /* Foot shooting limit for queues. */
        dn_cfg.byte_limit = 1024 * 1024;
        dn_cfg.expire = 1;

        /* RED parameters */
        dn_cfg.red_lookup_depth = 256;  /* default lookup table depth */
        dn_cfg.red_avg_pkt_size = 512;  /* default medium packet size */
        dn_cfg.red_max_pkt_size = 1500; /* default max packet size */

        /* hash tables */
        dn_cfg.max_hash_size = 65536;   /* max in the hash tables */
        dn_cfg.hash_size = 64;          /* default hash size */

        /* create hash tables for schedulers and flowsets.
         * In both we search by key and by pointer.
         */
        dn_cfg.schedhash = dn_ht_init(NULL, dn_cfg.hash_size,
                offsetof(struct dn_schk, schk_next),
                schk_hash, schk_match, schk_new);
        dn_cfg.fshash = dn_ht_init(NULL, dn_cfg.hash_size,
                offsetof(struct dn_fsk, fsk_next),
                fsk_hash, fsk_match, fsk_new);

        /* bucket index to drain object */
        dn_cfg.drain_fs = 0;
        dn_cfg.drain_sch = 0;

        heap_init(&dn_cfg.evheap, 16, offsetof(struct dn_id, id));
        SLIST_INIT(&dn_cfg.fsu);
        SLIST_INIT(&dn_cfg.schedlist);

        DN_LOCK_INIT();

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

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

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

#ifdef KLD_MODULE
static void
ip_dn_destroy(int last)
{
        callout_drain(&dn_timeout);

        DN_BH_WLOCK();
        if (last) {
                ND("removing last instance\n");
                ip_dn_ctl_ptr = NULL;
                ip_dn_io_ptr = NULL;
        }

        dummynet_flush();
        DN_BH_WUNLOCK();
        taskqueue_drain(dn_tq, &dn_task);
        taskqueue_free(dn_tq);

        dn_ht_free(dn_cfg.schedhash, 0);
        dn_ht_free(dn_cfg.fshash, 0);
        heap_free(&dn_cfg.evheap);

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

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) {
#if !defined(KLD_MODULE)
                printf("dummynet statically compiled, cannot unload\n");
                return EINVAL ;
#else
                ip_dn_destroy(1 /* last */);
                return 0;
#endif
        } 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 */
        DN_BH_WLOCK();
        SLIST_FOREACH(s, &dn_cfg.schedlist, next) {
                if (strcmp(s->name, d->name) == 0) {
                        D("%s already loaded", d->name);
                        break; /* scheduler already exists */
                }
        }
        if (s == NULL)
                SLIST_INSERT_HEAD(&dn_cfg.schedlist, d, next);
        DN_BH_WUNLOCK();
        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);

        DN_BH_WLOCK();
        SLIST_FOREACH_SAFE(r, &dn_cfg.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)
                        SLIST_REMOVE(&dn_cfg.schedlist, r, dn_alg, next);
                break;
        }
        DN_BH_WUNLOCK();
        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_IFATTACHDOMAIN
#define DN_MODEV_ORD    (SI_ORDER_ANY - 128) /* after ipfw */
DECLARE_MODULE(dummynet, dummynet_mod, DN_SI_SUB, DN_MODEV_ORD);
MODULE_DEPEND(dummynet, ipfw, 2, 2, 2);
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_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_destroy, NULL);

/* end of file */