Bring in new files for dummynet support

2 files changed, 709 insertions, 0 deletions

diff --git a/sys/netinet/ip_dummynet.c b/sys/netinet/ip_dummynet.c
new file mode 100644
index 0000000..31b4249
--- /dev/null
+++ b/sys/netinet/ip_dummynet.c
@@ -0,0 +1,609 @@
+/*
+ * Copyright (c) 1998 Luigi Rizzo
+ *
+ * Redistribution and use in source forms, with and without modification,
+ * are permitted provided that this entire comment appears intact.
+ *
+ * Redistribution in binary form may occur without any restrictions.
+ * Obviously, it would be nice if you gave credit where credit is due
+ * but requiring it would be too onerous.
+ *
+ * This software is provided ``AS IS'' without any warranties of any kind.
+ *
+ *	$Id: ip_dummynet.c 1.2 1998/08/21 15:01:13 luigi Exp $
+ */
+
+/*
+ * This module implements IP dummynet, a bandwidth limiter/delay emulator
+ * used in conjunction with the ipfw package.
+ *
+ * Changes:
+ *
+ * 980821: changed conventions in the queueing logic
+ *	packets passed from dummynet to ip_in/out are prepended with
+ *	a vestigial mbuf type MT_DUMMYNET which contains a pointer
+ *	to the matching rule.
+ *	ip_input/output will extract the parameters, free the vestigial mbuf,
+ *	and do the processing.
+ *     
+ * 980519:	fixed behaviour when deleting rules.
+ * 980518:	added splimp()/splx() to protect against races
+ * 980513:	initial release
+ */
+
+/* include files marked with XXX are probably not needed */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/queue.h>			/* XXX */
+#include <sys/kernel.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/sysctl.h>
+#include <net/if.h>
+#include <net/route.h>
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/in_var.h>
+#include <netinet/ip.h>
+#include <netinet/ip_fw.h>
+#include <netinet/ip_dummynet.h>
+
+#ifdef BRIDGE
+#include <netinet/if_ether.h> /* for struct arpcom */
+#include <net/bridge.h>
+#endif
+
+static struct dn_pipe *all_pipes = NULL ;	/* list of all pipes */
+
+static int dn_debug = 0 ;			/* verbose */
+static int dn_calls = 0 ;			/* number of calls */
+static int dn_idle = 1;
+#ifdef SYSCTL_NODE
+SYSCTL_NODE(_net_inet_ip, OID_AUTO, dummynet, CTLFLAG_RW, 0, "Dummynet");
+SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, debug, CTLFLAG_RW, &dn_debug, 0, "");
+SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, calls, CTLFLAG_RD, &dn_calls, 0, "");
+SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, idle, CTLFLAG_RD, &dn_idle, 0, "");
+#endif
+
+static int ip_dn_ctl(int optname, struct mbuf **mm);
+
+static void dummynet(void);
+static void dn_restart(void);
+static void dn_move(struct dn_pipe *pipe, int immediate);
+
+/*
+ * the following is needed when deleting a pipe, because rules can
+ * hold references to the pipe.
+ */
+extern LIST_HEAD (ip_fw_head, ip_fw_chain) ip_fw_chain;
+
+/*
+ * invoked to reschedule the periodic task if necessary.
+ * Should only be called when dn_idle = 1 ;
+ */
+static void
+dn_restart()
+{
+    struct dn_pipe *pipe;
+
+    if (!dn_idle)
+	return;
+	
+    for (pipe = all_pipes ; pipe ; pipe = pipe->next ) {
+	/* if there any pipe that needs work, restart */
+	if (pipe->r.head || pipe->p.head || pipe->numbytes < 0 ) {
+	    dn_idle = 0;
+	    timeout(dummynet, (caddr_t)NULL, 1);
+	    return ;
+	}
+    }
+}
+
+/*
+ * move packets from R-queue to P-queue
+ */
+static void
+dn_move(struct dn_pipe *pipe, int immediate)
+{
+    struct dn_pkt *tmp, *pkt;
+ 
+    /*
+     * consistency check, should catch new pipes which are
+     * not initialized properly.
+     */
+    if ( pipe->p.head == NULL &&
+		pipe->ticks_from_last_insert != pipe->delay) {
+	printf("Warning, empty pipe and delay %d (should be %a)d\n",
+		pipe->ticks_from_last_insert, pipe->delay);
+	pipe->ticks_from_last_insert = pipe->delay;
+    }
+    /* this ought to go in dn_dequeue() */
+    if (!immediate && pipe->ticks_from_last_insert < pipe->delay)
+	pipe->ticks_from_last_insert++;
+    if ( pkt = pipe->r.head ) {
+	/*
+	 * Move at most numbytes bytes from src and move to dst.
+	 * delay is set to ticks_from_last_insert, which
+	 * is reset after the first insertion;
+	 */
+	while ( pkt ) {
+	    struct ip *ip=mtod(pkt->dn_m, struct ip *);
+
+	    /*
+	     * queue limitation: pass packets down if the len is
+	     * such that the pkt would go out before the next tick.
+	     */
+	    if (pipe->bandwidth) {
+		if (pipe->numbytes < ip->ip_len)
+		    break;
+		pipe->numbytes -= ip->ip_len;
+	    }
+	    pipe->r_len--; /* elements in queue */
+	    pipe->r_len_bytes -= ip->ip_len ;
+
+	    /*
+	     * to add delay jitter, must act here. A lower value
+	     * (bounded to 0) means lower delay.
+	     */
+	    pkt->delay = pipe->ticks_from_last_insert;
+	    pipe->ticks_from_last_insert = 0;
+	    /* compensate the decrement done next in dn_dequeue */
+	    if (!immediate && pkt->delay >0 && pipe->p.head==NULL)
+		pkt->delay++;
+	    if (pipe->p.head == NULL)
+		pipe->p.head = pkt;
+	    else
+		(struct dn_pkt *)pipe->p.tail->dn_next = pkt;
+	    pipe->p.tail = pkt;
+	    pkt = (struct dn_pkt *)pkt->dn_next;
+	    pipe->p.tail->dn_next = NULL;
+	}
+	pipe->r.head = pkt;
+ 
+	/*** XXX just a sanity check */
+	if ( ( pkt == NULL && pipe->r_len != 0) ||
+	     ( pkt != NULL && pipe->r_len == 0) )
+	    printf("-- Warning, pipe head %x len %d\n",
+		    pkt, pipe->r_len);
+    }
+ 
+    /*
+     * deliver packets downstream after the delay in the P-queue.
+     */
+
+    if (pipe->p.head == NULL)
+	return;
+    if (!immediate)
+	pipe->p.head->delay--;
+    while ( (pkt = pipe->p.head) && pkt->delay < 1) {
+	/*
+	 * first unlink, then call procedures since ip_input()
+	 * can result in a call to ip_output cnd viceversa,
+	 * thus causing nested calls
+	 */
+	pipe->p.head = (struct dn_pkt *) pkt->dn_next ;
+
+	/*
+	 * the trick to avoid flow-id settings here is to prepend a
+	 * vestigial mbuf to the packet, with the following values:
+	 * m_type = MT_DUMMYNET
+	 * m_next = the actual mbuf to be processed by ip_input/output
+	 * m_data = the matching rule
+	 * The vestigial element is the same memory area used by
+	 * the dn_pkt, and IS FREED IN ip_input/ip_output. IT IS
+	 * NOT A REAL MBUF, just a block of memory acquired with malloc().
+	 */
+	switch (pkt->dn_dir) {
+	case DN_TO_IP_OUT: {
+	    struct rtentry *tmp_rt = pkt->ro.ro_rt ;
+
+	    (void)ip_output((struct mbuf *)pkt, (struct mbuf *)pkt->ifp,
+			&(pkt->ro), pkt->dn_hlen, NULL);
+	    if (tmp_rt)
+		 tmp_rt->rt_refcnt--; /* XXX return a reference count */
+	    }
+	    break ;
+	case DN_TO_IP_IN :
+	    ip_input((struct mbuf *)pkt) ;
+	    break ;
+#ifdef BRIDGE
+	case DN_TO_BDG_FWD :
+	    bdg_forward((struct mbuf **)&pkt, pkt->ifp);
+	    break ;
+#endif
+	default:
+	    printf("dummynet: bad switch %d!\n", pkt->dn_dir);
+	    m_freem(pkt->dn_m);
+	    FREE(pkt, M_IPFW);
+	    break ;
+	}
+    }
+}
+/*
+ * this is the periodic task that moves packets between the R-
+ * and the P- queue
+ */
+void
+dummynet()
+{
+    struct dn_pipe *p ;
+    int s ;
+
+    dn_calls++ ;
+    for (p = all_pipes ; p ; p = p->next ) {
+	/*
+	 * Increment the amount of data that can be sent. However,
+	 * don't do that if the channel is idle
+	 * (r.head == NULL && numbytes >= bandwidth).
+	 * This bug fix is from tim shepard (shep@bbn.com)
+	 */
+        s = splimp();
+	if (p->r.head != NULL || p->numbytes < p->bandwidth )
+		p->numbytes += p->bandwidth ;
+	dn_move(p, 0); /* is it really 0 (also below) ? */
+	splx(s);
+    }
+ 
+    /*
+     * finally, if some queue has data, restart the timer.
+     */
+    dn_idle = 1;
+    dn_restart();
+}
+
+/*
+ * dummynet hook for packets.
+ * input and output use the same code, so i use bit 16 in the pipe
+ * number to chose the direction: 1 for output packets, 0 for input.
+ * for input, only m is significant. For output, also the others.
+ */
+int
+dummynet_io(int pipe_nr, int dir,
+	struct mbuf *m, struct ifnet *ifp, struct route *ro, int hlen,
+	struct ip_fw_chain *rule)
+{
+    struct dn_pkt *pkt;
+    struct dn_pipe *pipe;
+    struct ip *ip=mtod(m, struct ip *);
+
+    int s=splimp();
+
+    pipe_nr &= 0xffff ;
+    /*
+     * locate pipe. First time is expensive, next have direct access.
+     */
+
+    if ( (pipe = rule->rule->pipe_ptr) == NULL ) {
+	for (pipe=all_pipes; pipe && pipe->pipe_nr !=pipe_nr; pipe=pipe->next)
+	    ;
+	if (pipe == NULL) {
+	    splx(s);
+	    if (dn_debug)
+		printf("warning, pkt for no pipe %d\n", pipe_nr);
+	    m_freem(m);
+	    return 0 ;
+	} else
+	    rule->rule->pipe_ptr = pipe ;
+    }
+ 
+    /*
+     * should i drop ?
+     * This section implements random packet drop.
+     */
+    if ( (pipe->plr && random() < pipe->plr) ||
+         (pipe->queue_size && pipe->r_len >= pipe->queue_size) ||
+         (pipe->queue_size_bytes &&
+	    ip->ip_len + pipe->r_len_bytes > pipe->queue_size_bytes) ||
+		(pkt = (struct dn_pkt *)malloc(sizeof (*pkt),
+			M_IPFW, M_NOWAIT) ) == NULL ) {
+	splx(s);
+	if (dn_debug)
+	    printf("-- dummynet: drop from pipe %d, have %d pks, %d bytes\n",
+		pipe_nr,  pipe->r_len, pipe->r_len_bytes);
+	pipe->r_drops++ ;
+	m_freem(m);
+	return 0 ; /* XXX error */
+    }
+    /* build and enqueue packet */
+    pkt->hdr.mh_type = MT_DUMMYNET ;
+    (struct ip_fw_chain *)pkt->hdr.mh_data = rule ;
+    pkt->dn_next = NULL;
+    pkt->dn_m = m;
+    pkt->dn_dir = dir ;
+    pkt->delay = 0;
+
+    pkt->ifp = ifp;
+    if (dir == DN_TO_IP_OUT) {
+	pkt->ro = *ro; /* XXX copied! */
+	if (ro->ro_rt)
+	    ro->ro_rt->rt_refcnt++ ; /* XXX */
+    }
+    pkt->dn_hlen = hlen;
+    if (pipe->r.head == NULL)
+	pipe->r.head = pkt;
+    else
+	(struct dn_pkt *)pipe->r.tail->dn_next = pkt;
+    pipe->r.tail = pkt;
+    pipe->r_len++;
+    pipe->r_len_bytes += ip->ip_len ;
+
+    /* 
+     * here we could implement RED if we like to
+     */
+
+    if (pipe->r.head == pkt) {       /* process immediately */
+        dn_move(pipe, 1);
+    }
+    splx(s);
+    if (dn_idle)
+	dn_restart();
+    return 0;
+}
+
+/*
+ * dispose all packets queued on a pipe
+ */
+static void
+purge_pipe(struct dn_pipe *pipe)
+{
+    struct dn_pkt *pkt, *n ;
+    struct rtentry *tmp_rt ;
+
+    for (pkt = pipe->r.head ; pkt ; ) {
+	if (tmp_rt = pkt->ro.ro_rt )
+	     tmp_rt->rt_refcnt--; /* XXX return a reference count */
+	m_freem(pkt->dn_m);
+	n = pkt ;
+	pkt = (struct dn_pkt *)pkt->dn_next ;
+	free(n, M_IPFW) ;
+    }
+    for (pkt = pipe->p.head ; pkt ; ) {
+	if (tmp_rt = pkt->ro.ro_rt )
+	     tmp_rt->rt_refcnt--; /* XXX return a reference count */
+	m_freem(pkt->dn_m);
+	n = pkt ;
+	pkt = (struct dn_pkt *)pkt->dn_next ;
+	free(n, M_IPFW) ;
+    }
+}
+
+/*
+ * delete all pipes returning memory
+ */
+static void
+dummynet_flush()
+{
+    struct dn_pipe *q, *p = all_pipes ;
+    int s = splnet() ;
+
+    all_pipes = NULL ;
+    splx(s) ;
+    /*
+     * purge all queued pkts and delete all pipes
+     */
+    for ( ; p ; ) {
+	purge_pipe(p);
+	q = p ;
+	p = p->next ;	
+	free(q, M_IPFW);
+    }
+}
+
+extern struct ip_fw_chain *ip_fw_default_rule ;
+/*
+ * when a firewall rule is deleted, scan all pipes and remove the flow-id
+ * from packets matching this rule.
+ */
+void
+dn_rule_delete(void *r)
+{
+
+    struct dn_pipe *q, *p = all_pipes ;
+
+    for ( p= all_pipes ; p ; p = p->next ) {
+	struct dn_pkt *x ;
+	for (x = p->r.head ; x ; x = (struct dn_pkt *)x->dn_next )
+	    if (x->hdr.mh_data == r)
+		x->hdr.mh_data = (void *)ip_fw_default_rule ;
+	for (x = p->p.head ; x ; x = (struct dn_pkt *)x->dn_next )
+	    if (x->hdr.mh_data == r)
+		x->hdr.mh_data = (void *)ip_fw_default_rule ;
+    }
+}
+
+/*
+ * handler for the various dummynet socket options
+ * (get, flush, config, del)
+ */
+static int
+ip_dn_ctl(int optname, struct mbuf **mm)
+{
+	struct mbuf *m ;
+	if (optname == IP_DUMMYNET_GET) {
+	    struct dn_pipe *p = all_pipes ;
+	    *mm = m = m_get(M_WAIT, MT_SOOPTS);
+	    m->m_len = 0 ;
+	    m->m_next = NULL ;
+	    for (; p ;  p = p->next ) {
+		struct dn_pipe *q = mtod(m,struct dn_pipe *) ;
+		memcpy( m->m_data, p, sizeof(*p) );
+		/*
+		 * return bw and delay in bits/s and ms, respectively
+		 */
+		q->bandwidth *= (8*hz) ;
+		q->delay = (q->delay * 1000) / hz ;
+
+		m->m_len = sizeof(*p) ;
+		m->m_next = m_get(M_WAIT, MT_SOOPTS);
+		m = m->m_next ;
+		m->m_len = 0 ;
+	    }
+	    return 0 ;
+	}
+	if (securelevel > 2) { /* like in the firewall code... */
+	    if (m) (void)m_free(m);
+	    return (EPERM) ;
+	}
+	m = *mm ;
+	if (optname == IP_DUMMYNET_FLUSH) {
+	    dummynet_flush() ;
+	    if (m) (void)m_free(m);
+	    return 0 ;
+	}
+	if (!m)		/* need an argument for the following */
+		return (EINVAL);
+	if (optname == IP_DUMMYNET_CONFIGURE) {
+	    struct dn_pipe *p = mtod(m,struct dn_pipe *) ;
+	    struct dn_pipe *x, *a, *b ;
+	    if (m->m_len != sizeof (*p) ) {
+		printf("dn_pipe Invalid length, %d instead of %d\n",
+			m->m_len, sizeof(*p) );
+		(void)m_free(m);
+		return (EINVAL);
+	    }
+	    /*
+	     * The config program passes parameters as follows:
+	     * bandwidth = bits/second (0 = no limits);
+	     *    must be translated in bytes/tick.
+	     * delay = ms
+	     *    must be translated in ticks.
+	     * queue_size = slots (0 = no limit)
+	     * queue_size_bytes = bytes (0 = no limit)
+	     *	  only one can be set, must be bound-checked
+	     */
+	    if ( p->bandwidth > 0 ) {
+		p->bandwidth = p->bandwidth / 8 / hz ;
+		if (p->bandwidth == 0)	/* too little does not make sense! */
+			p->bandwidth = 10 ;
+	    }
+	    p->delay = ( p->delay * hz ) / 1000 ;
+	    if (p->queue_size == 0 && p->queue_size_bytes == 0)
+		p->queue_size = 100 ;
+	    if (p->queue_size != 0 )	/* buffers are prevailing */
+		p->queue_size_bytes = 0 ;
+	    if (p->queue_size > 100)
+		p->queue_size = 100 ;
+	    if (p->queue_size_bytes > 1024*1024)
+		p->queue_size_bytes = 1024*1024 ;
+#if 0
+	    printf("ip_dn: config pipe %d %d bit/s %d ms %d bufs\n",
+		p->pipe_nr,
+		p->bandwidth * 8 * hz ,
+		p->delay * 1000 / hz , p->queue_size);
+#endif
+	    for (a = NULL , b = all_pipes ; b && b->pipe_nr < p->pipe_nr ;
+		 a = b , b = b->next) ;
+	    if (b && b->pipe_nr == p->pipe_nr) {
+		/* XXX should spl and flush old pipe... */
+		b->bandwidth = p->bandwidth ;
+		b->delay = p->delay ;
+		b->ticks_from_last_insert = p->delay ;
+		b->queue_size = p->queue_size ;
+		b->queue_size_bytes = p->queue_size_bytes ;
+		b->plr = p->plr ;
+	    } else {
+		int s ;
+		x = malloc(sizeof(struct dn_pipe), M_IPFW, M_DONTWAIT) ;
+		if (x == NULL) {
+		    printf("ip_dummynet.c: sorry no memory\n");
+		    return (ENOSPC) ;
+		}
+		bzero(x, sizeof(*x) );
+		x->bandwidth = p->bandwidth ;
+		x->delay = p->delay ;
+		x->ticks_from_last_insert = p->delay ;
+		x->pipe_nr = p->pipe_nr ;
+		x->queue_size = p->queue_size ;
+		x->queue_size_bytes = p->queue_size_bytes ;
+		x->plr = p->plr ;
+
+		s = splnet() ;
+		x->next = b ;
+		if (a == NULL)
+		    all_pipes = x ;
+		else
+		    a->next = x ;
+		splx(s);
+	    }
+	    (void)m_free(m);
+	    return 0 ;
+	}
+	if (optname == IP_DUMMYNET_DEL) {
+	    struct dn_pipe *p = mtod(m,struct dn_pipe *) ;
+	    struct dn_pipe *x, *a, *b ;
+
+	    for (a = NULL , b = all_pipes ; b && b->pipe_nr < p->pipe_nr ;
+		 a = b , b = b->next) ;
+	    if (b && b->pipe_nr == p->pipe_nr) {	/* found pipe */
+		int s = splnet() ;
+		struct ip_fw_chain *chain = ip_fw_chain.lh_first;
+
+		if (a == NULL)
+		    all_pipes = b->next ;
+		else
+		    a->next = b->next ;
+		/*
+		 * remove references to this pipe from the ip_fw rules.
+		 */
+		for (; chain; chain = chain->chain.le_next) {
+		    register struct ip_fw *const f = chain->rule;
+		    if (f->pipe_ptr == b)
+			f->pipe_ptr = NULL ;
+		}
+		splx(s);
+		purge_pipe(b);	/* remove pkts from here */
+		free(b, M_IPFW);
+	    }
+	}
+	return 0 ;
+}
+
+void
+ip_dn_init(void)
+{
+    printf("DUMMYNET initialized (980901) -- size dn_pkt %d\n",
+	sizeof(struct dn_pkt));
+    all_pipes = NULL ;
+    ip_dn_ctl_ptr = ip_dn_ctl;
+}
+
+#ifdef DUMMYNET_MODULE
+
+#include <sys/exec.h>
+#include <sys/sysent.h>
+#include <sys/lkm.h>
+
+MOD_MISC(dummynet);
+
+static ip_dn_ctl_t *old_dn_ctl_ptr ;
+
+static int
+dummynet_load(struct lkm_table *lkmtp, int cmd)
+{
+	int s=splnet();
+	old_dn_ctl_ptr = ip_dn_ctl_ptr;
+	ip_dn_init();
+	splx(s);
+	return 0;
+}
+
+static int
+dummynet_unload(struct lkm_table *lkmtp, int cmd)
+{
+	int s=splnet();
+	ip_dn_ctl_ptr =  old_dn_ctl_ptr;
+	splx(s);
+	dummynet_flush();
+	printf("DUMMYNET unloaded\n");
+	return 0;
+}
+
+int
+dummynet_mod(struct lkm_table *lkmtp, int cmd, int ver)
+{
+    DISPATCH(lkmtp, cmd, ver, dummynet_load, dummynet_unload, lkm_nullcmd);
+}
+#endif
diff --git a/sys/netinet/ip_dummynet.h b/sys/netinet/ip_dummynet.h
new file mode 100644
index 0000000..33833fc
--- /dev/null
+++ b/sys/netinet/ip_dummynet.h
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 1998 Luigi Rizzo
+ *
+ * Redistribution and use in source forms, with and without modification,
+ * are permitted provided that this entire comment appears intact.
+ *
+ * Redistribution in binary form may occur without any restrictions.
+ * Obviously, it would be nice if you gave credit where credit is due
+ * but requiring it would be too onerous.
+ *
+ * This software is provided ``AS IS'' without any warranties of any kind.
+ *
+ *	$Id: ip_dummynet.h,v 1.1 1998/05/10 01:30:23 luigi Exp $
+ */
+
+#ifndef _IP_DUMMYNET_H
+#define _IP_DUMMYNET_H
+
+/*
+ * Definition of dummynet data structures.
+ * Dummynet handles a list of pipes, each one identified by a unique
+ * number (hopefully the list is short so we use a linked list).
+ *
+ * Each list contains a set of parameters identifying the pipe, and
+ * a set of packets queued on the pipe itself.
+ *
+ * I could have used queue macros, but the management i have
+ * is pretty simple and this makes the code more portable.
+ */
+
+/*
+ * struct dn_pkt identifies a packet in the dummynet queue. The
+ * first part is really an m_hdr for implementation purposes, and some
+ * fields are saved there. When passing the packet back to the ip_input/
+ * ip_output(), the struct is prepended to the mbuf chain with type
+ * MT_DUMMYNET, and contains the pointer to the matching rule.
+ */
+struct dn_pkt {
+	struct m_hdr hdr ;
+#define dn_next	hdr.mh_nextpkt	/* next element in queue */
+#define dn_m	hdr.mh_next	/* packet to be forwarded */
+#define dn_hlen	hdr.mh_len	/* hlen, for ip_output			*/
+#define dn_dir	hdr.mh_flags	/* IP_FW_F_IN or IP_FW_F_OUT		*/
+        int     delay;		/* stays queued until delay=0		*/
+        struct ifnet *ifp;	/* interface, for ip_output		*/
+        struct route ro;	/* route, for ip_output. MUST COPY	*/
+
+#ifdef   DUMMYNET_DEBUG
+        struct timeval beg, mid;        /* testing only */
+        int     act_delay;      /* testing only */
+        int     in_delay;       /* testing only */
+#endif
+};
+
+struct dn_queue {
+	struct dn_pkt *head, *tail;
+} ;
+
+/*
+ * descriptor of a pipe. The flags field will be used to speed up the
+ * forwarding code paths, in case some of the parameters are not
+ * used.
+ */
+struct dn_pipe {			/* a pipe */
+	struct dn_pipe *next ;
+
+	u_short	pipe_nr ;		/* number	*/
+	u_short	flags ;			/* to speed up things	*/
+#define DN_HAVE_BW	1
+#define DN_HAVE_QUEUE	2
+#define DN_HAVE_DELAY	4
+	int	bandwidth;		/* really, bytes/tick.	*/
+	int	queue_size ;
+	int	queue_size_bytes ;
+	int	delay ;			/* really, ticks	*/
+	int	plr ;		/* pkt loss rate (2^31-1 means 100%) */
+
+        struct	dn_queue r;
+        int	r_len;			/* elements in r_queue */
+        int	r_len_bytes;		/* bytes in r_queue */
+        int	r_drops;		/* drops from r_queue */
+        struct	dn_queue p ;
+        int     ticks_from_last_insert;
+        long    numbytes;		/* which can send or receive */
+};
+
+/*
+ * what to do of a packet when it comes out of a pipe
+ */
+#define DN_TO_IP_OUT	1
+#define DN_TO_IP_IN	2
+#define DN_TO_BDG_FWD	3
+#ifdef KERNEL
+void ip_dn_init(void);	/* called in ip_input.c */
+void dn_rule_delete(void *r);		/* used in ip_fw.c */
+int dummynet_io(int pipe, int dir,
+	struct mbuf *m, struct ifnet *ifp, struct route *ro, int hlen,
+	struct ip_fw_chain *rule);
+#endif
+#endif /* _IP_DUMMYNET_H */