Major overhaul.

 List of functional changes:
   - Make a single device per single node with a single hook.
     This gives us parrallelizm, which can't be achieved on a single
     node with many devices/hooks. This also gives us flexibility - we
     can play with a particular device node, not affecting others.
   - Remove read queue as it is. Use struct ifqueue instead. This change
     removes a lot of extra memcpy()ing, m_devget()ting and m_copymem()ming.
     In ng_device_receivedata() we enqueue an mbuf and wake readers.
     In ngdread() we take one mbuf from qeueue and uiomove() it to
     userspace. If no mbuf is present we optionally block. [1]
   - In ngdwrite() we create an mbuf from uio using m_uiotombuf().
     This is faster then uiomove() into buffer, and then m_copydata(),
     and this is much better than huge m_pullup().
   - Perform locking of device
   - Perform locking of connection list.
   - Clear out _rcvmsg method, since it does nothing good yet.
   - Implement NGM_DEVICE_GET_DEVNAME message.
   - #if 0 ioctl method, while nothing is done here yet.
   - Return immediately from ngdwrite() if uio_resid == 0.

 List of tidyness changes:
   - Introduce device2priv(), to remove cut'n'paste.
   - Use MALLOC/FREE, instead of malloc/free.
   - Use unit2minor().
   - Use UID_ROOT/GID_WHEEL instead of 0/0.
   - Define NGD_DEVICE_DEVNAME, use it.
   - Use more nice macros for debugging. [2]
   - Return Exxx, not -1.

 style(9) changes:
   - No "#endif" after short block.
   - Break long lines.
   - Remove extra spaces, add needed spaces.

[1] Obtained from:      if_tun.c
[2] Obtained from:      ng_pppoe.c
Reviewed by:		marks
Approved by:		julian (mentor)
MFC after:		1 month

3 files changed, 281 insertions, 361 deletions

diff --git a/sys/modules/netgraph/device/Makefile b/sys/modules/netgraph/device/Makefile
index 9f85151..92eaa98 100644
--- a/sys/modules/netgraph/device/Makefile
+++ b/sys/modules/netgraph/device/Makefile
@@ -2,6 +2,6 @@
 KMOD=   ng_device
 SRCS=   ng_device.c
 
-SRCS+=   device_if.h
+SRCS+=   device_if.h vnode_if.h
 
 .include <bsd.kmod.mk>
diff --git a/sys/netgraph/ng_device.c b/sys/netgraph/ng_device.c
index 7dcaea3..c209fd1 100644
--- a/sys/netgraph/ng_device.c
+++ b/sys/netgraph/ng_device.c
@@ -23,13 +23,19 @@
  *
  * Netgraph "device" node
  *
- * This node presents a /dev/ngd%d device that interfaces to an other 
+ * This node presents a /dev/ngd%d device that interfaces to an other
  * netgraph node.
  *
  * $FreeBSD$
  *
  */
 
+#if 0
+#define AAA printf("ng_device: %s\n", __func__ );
+#else
+#define AAA
+#endif
+
 #include <sys/param.h>
 #include <sys/conf.h>
 #include <sys/ioccom.h>
@@ -38,407 +44,328 @@
 #include <sys/mbuf.h>
 #include <sys/poll.h>
 #include <sys/queue.h>
+#include <sys/socket.h>
 #include <sys/systm.h>
 #include <sys/uio.h>
+#include <sys/vnode.h>
+
+#include <net/if.h>
+#include <net/if_var.h>
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
 
 #include <netgraph/ng_message.h>
 #include <netgraph/netgraph.h>
 #include <netgraph/ng_device.h>
 
-/* turn this on for verbose messages */
-#define NGD_DEBUG
-
 #define	ERROUT(x) do { error = (x); goto done; } while (0)
 
 /* Netgraph methods */
-static ng_constructor_t	ng_device_cons;
+static ng_constructor_t	ng_device_constructor;
 static ng_rcvmsg_t	ng_device_rcvmsg;
+static ng_shutdown_t	ng_device_shutdown;
 static ng_newhook_t	ng_device_newhook;
-static ng_connect_t 	ng_device_connect;
 static ng_rcvdata_t	ng_device_rcvdata;
 static ng_disconnect_t	ng_device_disconnect;
-static int              ng_device_mod_event(module_t mod, int event, void *data);
-
-static int ng_device_init(void);
-static int get_free_unit(void);
 
 /* Netgraph type */
-static struct ng_type typestruct = {
+static struct ng_type ngd_typestruct = {
 	.version =	NG_ABI_VERSION,
 	.name =		NG_DEVICE_NODE_TYPE,
-	.mod_event =	ng_device_mod_event,
-	.constructor =	ng_device_cons,
-	.rcvmsg =	ng_device_rcvmsg,
+	.constructor =	ng_device_constructor,
+	.rcvmsg	=	ng_device_rcvmsg,
+	.shutdown = 	ng_device_shutdown,
 	.newhook =	ng_device_newhook,
-	.connect = 	ng_device_connect,
 	.rcvdata =	ng_device_rcvdata,
 	.disconnect =	ng_device_disconnect,
 };
-NETGRAPH_INIT(device, &typestruct);
-
-/* per hook data */
-struct ngd_connection {
-	SLIST_ENTRY(ngd_connection) links;
-
-	struct cdev *ngddev;
-	struct 	ng_hook *active_hook;
-	char	*readq;
-	int 	loc;
-	int 	unit;
+NETGRAPH_INIT(device, &ngd_typestruct);
+
+/* per node data */
+struct ngd_private {
+	struct	ifqueue	readq;
+	SLIST_ENTRY(ngd_private) links;
+	struct	ng_node	*node;
+	struct	ng_hook	*hook;
+	struct	cdev	*ngddev;
+	struct	mtx	ngd_mtx;
+	int 		unit;
+	uint16_t	flags;
+#define	NGDF_OPEN	0x0001
+#define	NGDF_RWAIT	0x0002
 };
+typedef struct ngd_private *priv_p;
 
-/* global data */
-struct ngd_softc {
-	SLIST_HEAD(, ngd_connection) head;
-
-	node_p node;
-	char nodename[NG_NODESIZ];
-} ngd_softc;
-
-/* the per connection receiving queue maximum */
-#define NGD_QUEUE_SIZE (1024*10)
+/* List of all active nodes and mutex to protect it */
+static SLIST_HEAD(, ngd_private) ngd_nodes = SLIST_HEAD_INITIALIZER(ngd_nodes);
+static struct mtx	ng_device_mtx;
+MTX_SYSINIT(ng_device, &ng_device_mtx, "ng_device", MTX_DEF);
 
 /* Maximum number of NGD devices */
-#define MAX_NGD	25 		/* should be more than enough for now */
+#define MAX_NGD	25	/* should be more than enough for now */
 
 static d_close_t ngdclose;
 static d_open_t ngdopen;
 static d_read_t ngdread;
 static d_write_t ngdwrite;
+#if 0
 static d_ioctl_t ngdioctl;
+#endif
 static d_poll_t ngdpoll;
 
 static struct cdevsw ngd_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_NEEDGIANT,
 	.d_open =	ngdopen,
 	.d_close =	ngdclose,
 	.d_read =	ngdread,
 	.d_write =	ngdwrite,
+#if 0
 	.d_ioctl =	ngdioctl,
+#endif
 	.d_poll =	ngdpoll,
-	.d_name =	"ngd",
+	.d_name =	NG_DEVICE_DEVNAME,
 };
 
-/* 
- * this holds all the stuff that should be done at load time 
+/* Helper functions */
+static int get_free_unit(void);
+
+/******************************************************************************
+ *  Netgraph methods
+ ******************************************************************************/
+
+/*
+ * create new node
  */
 static int
-ng_device_mod_event(module_t mod, int event, void *data)
+ng_device_constructor(node_p node)
 {
-	int error = 0;
+	priv_p	priv;
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
+AAA
 
-	switch (event) {
-		case MOD_LOAD:
+	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
+	if (priv == NULL)
+		return (ENOMEM);
 
-			ng_device_init();
-			break;
+	mtx_init(&priv->ngd_mtx, "ng_device", NULL, MTX_DEF);
+	mtx_lock(&priv->ngd_mtx);
 
-		case MOD_UNLOAD:
-			/* XXX do we need to do something specific ? */
-			/* ng_device_breakdown */
-			break;
-		
-		default:
-			error = EOPNOTSUPP;
-			break;
-	}
+	mtx_lock(&ng_device_mtx);
 
-	return(error);
-}
+	priv->unit = get_free_unit();
+	if(priv->unit < 0) {
+		printf("%s: No free unit found by get_free_unit(), "
+				"increase MAX_NGD\n",__func__);
+		mtx_unlock(&ng_device_mtx);
+		mtx_destroy(&priv->ngd_mtx);
+		FREE(priv, M_NETGRAPH);
+		return(EINVAL);
+	}
 
+	priv->ngddev = make_dev(&ngd_cdevsw, unit2minor(priv->unit), UID_ROOT,
+	    GID_WHEEL, 0600, NG_DEVICE_DEVNAME "%d", priv->unit);
+	if(priv->ngddev == NULL) {
+		printf("%s(): make_dev() failed\n",__func__);
+		mtx_unlock(&ng_device_mtx);
+		mtx_destroy(&priv->ngd_mtx);
+		FREE(priv, M_NETGRAPH);
+		return(EINVAL);
+	}
 
-static int
-ng_device_init()
-{
-        struct ngd_softc *sc = &ngd_softc;
-	
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */ 
-
-	SLIST_INIT(&sc->head);
-
-        if (ng_make_node_common(&typestruct, &sc->node) != 0) {
-                printf("%s(): ng_make_node_common failed\n",__func__);
-                return(ENXIO);
-        }
-        sprintf(sc->nodename, "%s", NG_DEVICE_NODE_TYPE);
-        if (ng_name_node(sc->node, sc->nodename)) {
-                NG_NODE_UNREF(sc->node); /* make it go away again */
-                printf("%s(): ng_name_node failed\n",__func__);
-                return(ENXIO);
-        }
-        NG_NODE_SET_PRIVATE(sc->node, sc);
+	SLIST_INSERT_HEAD(&ngd_nodes, priv, links);
 
-	return(0);
-}
+	mtx_unlock(&ng_device_mtx);
 
-/* 
- * don't allow to be created, only the device can do that 
- */
-static int
-ng_device_cons(node_p node)
-{
+	mtx_init(&priv->readq.ifq_mtx, "ng_device queue", NULL, MTX_DEF);
+	IFQ_SET_MAXLEN(&priv->readq, ifqmaxlen);
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
+	/* Link everything together */
+	NG_NODE_SET_PRIVATE(node, priv);
+	priv->node = node;
+	priv->ngddev->si_drv1 = priv;
 	
-	return(EINVAL);
+	mtx_unlock(&priv->ngd_mtx);
+
+	return(0);
 }
 
 /*
- * Receive control message. We just bounce it back as a reply.
+ * Process control message.
  */
+
 static int
 ng_device_rcvmsg(node_p node, item_p item, hook_p lasthook)
 {
-        struct ngd_softc *sc = &ngd_softc;
+	const priv_p priv = NG_NODE_PRIVATE(node);
 	struct ng_mesg *msg;
+	struct ng_mesg *resp = NULL;
 	int error = 0;
-	struct ngd_connection * connection = NULL;
-	struct ngd_connection *tmp = NULL;
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
+	NGI_GET_MSG(item, msg);
 
-	NGI_GET_MSG(item, msg); 
+	if (msg->header.typecookie == NGM_DEVICE_COOKIE) {
+		switch (msg->header.cmd) {
+		case NGM_DEVICE_GET_DEVNAME:
+			/* XXX: Fix when NGD_MAX us bigger */
+			NG_MKRESPONSE(resp, msg,
+			    strlen(NG_DEVICE_DEVNAME) + 3, M_NOWAIT);
 
-	SLIST_FOREACH(tmp,&sc->head,links) {
-		if(tmp->active_hook == lasthook) {
-			connection = tmp;
-		}
-	}
-	if(connection == NULL) {
-		printf("%s(): connection is still NULL, no hook found\n",__func__);
-		return(-1);
-	}
+			if (resp == NULL)
+				ERROUT(ENOMEM);
 
-	return(error);
-}
-
-static int
-get_free_unit()
-{
-	struct ngd_connection *tmp = NULL;
-	struct ngd_softc *sc = &ngd_softc;
-	int n = 0;
-	int unit = -1;
-
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
-
-	/* When there is no list yet, the first device unit is always 0. */
-	if SLIST_EMPTY(&sc->head) {
-		unit = 0;
-		return(unit);
-	}
-
-	/* Just do a brute force loop to find the first free unit that is
-	 * smaller than MAX_NGD.
-	 * Set MAX_NGD to a large value, doesn't impact performance.
-	 */
-	for(n = 0;n<MAX_NGD && unit == -1;n++) {
-		SLIST_FOREACH(tmp,&sc->head,links) {
+			strlcpy((char *)resp->data, priv->ngddev->si_name,
+			    strlen(priv->ngddev->si_name) + 1);
+			break;
 
-			if(tmp->unit == n) {
-				unit = -1;
-				break;
-			}
-			unit = n;
+		default:
+			error = EINVAL;
+			break;
 		}
-	}
+	} else
+		error = EINVAL;
 
-	return(unit);
+done:
+	NG_RESPOND_MSG(error, node, item, resp);
+	NG_FREE_MSG(msg);
+	return (error);
 }
 
 /*
- * incoming hook
+ * Accept incoming hook. We support only one hook per node.
  */
 static int
 ng_device_newhook(node_p node, hook_p hook, const char *name)
 {
-	struct ngd_softc *sc = &ngd_softc;
-	struct ngd_connection * new_connection = NULL;
-
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif
-
-	new_connection = malloc(sizeof(struct ngd_connection), M_DEVBUF, M_NOWAIT);
-	if(new_connection == NULL) {
-		printf("%s(): ERROR: new_connection == NULL\n",__func__);
-		return(ENOMEM);
-	}
-
-	new_connection->unit = get_free_unit();
-	if(new_connection->unit<0) {
-		printf("%s: No free unit found by get_free_unit(), "
-				"increase MAX_NGD\n",__func__);
-		free(new_connection, M_DEVBUF);
-		return(EINVAL);
-	}
-	new_connection->ngddev = make_dev(&ngd_cdevsw, new_connection->unit, 0, 0,0600,"ngd%d",new_connection->unit);
-	if(new_connection->ngddev == NULL) {
-		printf("%s(): make_dev failed\n",__func__);
-		free(new_connection, M_DEVBUF);
-		return(EINVAL);
-	}
-
-	new_connection->readq = malloc(sizeof(char)*NGD_QUEUE_SIZE, M_DEVBUF, M_NOWAIT | M_ZERO);
-	if(new_connection->readq == NULL) {
-		printf("%s(): readq malloc failed\n",__func__);
-		free(new_connection, M_DEVBUF);
-		return(ENOMEM);
-	}
-
-	/* point to begin of buffer */
-	new_connection->loc = 0;
-	new_connection->active_hook = hook;
-
-	SLIST_INSERT_HEAD(&sc->head, new_connection, links);
+	priv_p priv = NG_NODE_PRIVATE(node);
 
-	return(0);
-}
+AAA
 
-/*
- * we gave ok to a new hook
- * now connect
- */
-static int
-ng_device_connect(hook_p hook)
-{
+	/* We have only one hook per node */
+	if (priv->hook != NULL)
+		return (EISCONN);
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
+	priv->hook = hook;
 
 	return(0);
 }
 
-
 /*
- * Receive data from hook
+ * Receive data from hook, write it to device.
  */
 static int
 ng_device_rcvdata(hook_p hook, item_p item)
 {
+	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 	struct mbuf *m;
-	struct ngd_softc *sc = &ngd_softc;
-	struct ngd_connection * connection = NULL;
-	struct ngd_connection * tmp;
-	char *buffer;
-	int error = 0;
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif
+AAA
 
 	NGI_GET_M(item, m);
 	NG_FREE_ITEM(item);
 
-	SLIST_FOREACH(tmp,&sc->head,links)
-		if(tmp->active_hook == hook)
-			connection = tmp;
-
-	if (connection == NULL) {
-		printf("%s(): connection is still NULL, no hook found\n",__func__);
-		ERROUT(ENOTCONN);
-	}
-
-	if ((m = m_pullup(m,m->m_len)) == NULL) {
-		printf("%s(): ERROR: m_pullup failed\n",__func__);
-		ERROUT(ENOMEM);
+	IF_LOCK(&priv->readq);
+	if (_IF_QFULL(&priv->readq)) {
+		_IF_DROP(&priv->readq);
+		IF_UNLOCK(&priv->readq);
+		NG_FREE_M(m);
+		return (ENOBUFS);
 	}
 
-	buffer = mtod(m,char *);
-
-	if ((connection->loc + m->m_len) < NGD_QUEUE_SIZE) {
-	        memcpy(connection->readq + connection->loc, buffer, m->m_len);
-		connection->loc += m->m_len;
-	} else {
-		printf("%s(): queue full, first read out a bit\n",__func__);
-		ERROUT(ENOSPC);
+	_IF_ENQUEUE(&priv->readq, m);
+	IF_UNLOCK(&priv->readq);
+	mtx_lock(&priv->ngd_mtx);
+	if (priv->flags & NGDF_RWAIT) {
+		priv->flags &= ~NGDF_RWAIT;
+		wakeup(priv);
 	}
+	mtx_unlock(&priv->ngd_mtx);
 
-done:
-	NG_FREE_M(m);
-	return(error);
+	return(0);
 }
 
 /*
- * Removal of the last link destroys the node
+ * Removal of the hook destroys the node.
  */
 static int
 ng_device_disconnect(hook_p hook)
 {
-	struct ngd_softc *sc = &ngd_softc;
-	struct ngd_connection * connection = NULL;
-	struct ngd_connection * tmp;
+	priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif
+AAA
 
-	SLIST_FOREACH(tmp,&sc->head,links)
-		if(tmp->active_hook == hook)
-			connection = tmp;
+	destroy_dev(priv->ngddev);
+	mtx_destroy(&priv->ngd_mtx);
 
-	if(connection == NULL) {
-		printf("%s(): connection is still NULL, no hook found\n",__func__);
-		return(ENOTCONN);
-	}
+	mtx_lock(&ng_device_mtx);
+	SLIST_REMOVE(&ngd_nodes, priv, ngd_private, links);
+	mtx_unlock(&ng_device_mtx);
 
-        free(connection->readq, M_DEVBUF);
+	IF_DRAIN(&priv->readq);
+	mtx_destroy(&(priv)->readq.ifq_mtx);
 
-	destroy_dev(connection->ngddev);
+	FREE(priv, M_NETGRAPH);
 
-	SLIST_REMOVE(&sc->head,connection,ngd_connection,links);
-	free(connection, M_DEVBUF);
+	ng_rmnode_self(NG_HOOK_NODE(hook));
 
 	return(0);
 }
+
 /*
- * the device is opened 
+ * Node shutdown. Everything is already done in disconnect method.
+ */
+static int
+ng_device_shutdown(node_p node)
+{
+	NG_NODE_UNREF(node);
+	return (0);
+}
+
+/******************************************************************************
+ *  Device methods
+ ******************************************************************************/
+
+/*
+ * the device is opened
  */
 static int
 ngdopen(struct cdev *dev, int flag, int mode, struct thread *td)
 {
+	priv_p	priv = (priv_p )dev->si_drv1;
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
+AAA
+	mtx_lock(&priv->ngd_mtx);
+	priv->flags |= NGDF_OPEN;
+	mtx_unlock(&priv->ngd_mtx);
 
 	return(0);
 }
 
 /*
- * the device is closed 
+ * the device is closed
  */
 static int
 ngdclose(struct cdev *dev, int flag, int mode, struct thread *td)
 {
+	priv_p	priv = (priv_p )dev->si_drv1;
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif
+AAA
+	mtx_lock(&priv->ngd_mtx);
+	priv->flags &= ~NGDF_OPEN;
+	mtx_unlock(&priv->ngd_mtx);
 
 	return(0);
 }
 
-
+#if 0	/*
+	 * The ioctl is transformed into netgraph control message.
+	 * We do not process them, yet.
+	 */
 /*
  * process ioctl
  *
  * they are translated into netgraph messages and passed on
- * 
+ *
  */
 static int
 ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
@@ -448,11 +375,9 @@ ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td
 	struct ngd_connection * tmp;
 	int error = 0;
 	struct ng_mesg *msg;
-        struct ngd_param_s * datap;
+	struct ngd_param_s * datap;
 
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
+AAA
 
 	SLIST_FOREACH(tmp,&sc->head,links) {
 		if(tmp->ngddev == dev) {
@@ -464,8 +389,7 @@ ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td
 		return(-1);
 	}
 
-	/* NG_MKMESSAGE(msg, cookie, cmdid, len, how) */
-	NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s), 
+	NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
 			M_NOWAIT);
 	if (msg == NULL) {
 		printf("%s(): msg == NULL\n",__func__);
@@ -474,7 +398,7 @@ ngdioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td
 
 	/* pass the ioctl data into the ->data area */
 	datap = (struct ngd_param_s *)msg->data;
-        datap->p = addr;
+	datap->p = addr;
 
 	NG_SEND_MSG_HOOK(error, sc->node, msg, connection->active_hook, 0);
 	if(error)
@@ -484,108 +408,76 @@ nomsg:
 
 	return(0);
 }
-
+#endif /* if 0 */
 
 /*
  * This function is called when a read(2) is done to our device.
- * We pass the data available in kernelspace on into userland using
- * uiomove.
+ * We process one mbuf from queue.
  */
 static int
 ngdread(struct cdev *dev, struct uio *uio, int flag)
 {
-	int ret = 0, amnt;
-	char buffer[uio->uio_resid+1];
-	struct ngd_softc *sc = &ngd_softc;
-	struct ngd_connection * connection = NULL;
-	struct ngd_connection * tmp;
-
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
-
-	SLIST_FOREACH(tmp,&sc->head,links) {
-		if(tmp->ngddev == dev) {
-			connection = tmp;
+	priv_p	priv = (priv_p )dev->si_drv1;
+	struct mbuf *m;
+	int len, error = 0;
+
+AAA
+
+	/* get an mbuf */
+	do {
+		IF_DEQUEUE(&priv->readq, m);
+		if (m == NULL) {
+			if (flag & IO_NDELAY)
+				return (EWOULDBLOCK);
+			mtx_lock(&priv->ngd_mtx);
+			priv->flags |= NGDF_RWAIT;
+			mtx_unlock(&priv->ngd_mtx);
+			if ((error = tsleep(priv, PCATCH | (PZERO + 1),
+			    "ngdread", 0)) != 0)
+				return (error);
 		}
-	}
-	if(connection == NULL) {
-		printf("%s(): connection is still NULL, no dev found\n",__func__);
-		return(-1);
-	}
-
-	while ( ( uio->uio_resid > 0 ) && ( connection->loc > 0 ) ) {
-		amnt = MIN(uio->uio_resid,connection->loc);
-
-		memcpy(buffer,connection->readq, amnt);
-		memcpy(connection->readq, connection->readq+amnt,
-				connection->loc-amnt);
-		connection->loc -= amnt;
-
-		ret = uiomove((caddr_t)buffer, amnt, uio);
-		if(ret != 0)
-			goto error;
+	} while (m == NULL);
 
+	while (m && uio->uio_resid > 0 && error == 0) {
+		len = MIN(uio->uio_resid, m->m_len);
+		if (len != 0)
+			error = uiomove(mtod(m, void *), len, uio);
+		m = m_free(m);
 	}
-	return(0);
 
-error:
-	printf("%s(): uiomove returns error %d\n",__func__,ret);
-	/* do error cleanup here */
-	return(ret);
+	if (m)
+		m_freem(m);
+
+	return (error);
 }
 
 
-/* 
+/*
  * This function is called when our device is written to.
- * We read the data from userland into our local buffer and pass it on
- * into the remote hook.
+ * We read the data from userland into mbuf chain and pass it to the remote hook.
  *
  */
 static int
 ngdwrite(struct cdev *dev, struct uio *uio, int flag)
 {
-	int ret;
-	int error = 0;
+	priv_p	priv = (priv_p )dev->si_drv1;
 	struct mbuf *m;
-	char buffer[uio->uio_resid];
-	int len = uio->uio_resid;
-	struct ngd_softc *sc =& ngd_softc;
-	struct ngd_connection * connection = NULL;
-	struct ngd_connection * tmp;
-
-#ifdef NGD_DEBUG
-	printf("%s()\n",__func__);
-#endif /* NGD_DEBUG */
-
-	SLIST_FOREACH(tmp,&sc->head,links) {
-		if(tmp->ngddev == dev) {
-			connection = tmp;
-		}
-	}
-
-	if(connection == NULL) {
-		printf("%s(): connection is still NULL, no dev found\n",__func__);
-		return(-1);
-	}
+	int error = 0;
 
-	if (len > 0) {
-		if ((ret = uiomove((caddr_t)buffer, len, uio)) != 0)
-			goto error;
-	} else
-		printf("%s(): len <= 0 : is this supposed to happen?!\n",__func__);
+AAA
 
-	m = m_devget(buffer,len,0,NULL,NULL);
+	if (uio->uio_resid == 0)
+		return (0);
 
-	NG_SEND_DATA_ONLY(error,connection->active_hook,m);
+	if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
+		return (EIO);
 
-	return(0);
+	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL)
+		return (ENOBUFS);
 
-error:
-	/* do error cleanup here */
-	printf("%s(): uiomove returned err: %d\n",__func__,ret);
+	NG_SEND_DATA_ONLY(error, priv->hook, m);
 
-	return(ret);
+	return (error);
 }
 
 /*
@@ -595,28 +487,49 @@ error:
 static int
 ngdpoll(struct cdev *dev, int events, struct thread *td)
 {
+	priv_p	priv = (priv_p )dev->si_drv1;
 	int revents = 0;
-	struct ngd_softc *sc = &ngd_softc;
-	struct ngd_connection * connection = NULL;
-	struct ngd_connection * tmp;
 
+	if (events & (POLLIN | POLLRDNORM) &&
+	    !IFQ_IS_EMPTY(&priv->readq))
+		revents |= events & (POLLIN | POLLRDNORM);
+
+	return (revents);
+}
+
+/******************************************************************************
+ *  Helper subroutines
+ ******************************************************************************/
+
+static int
+get_free_unit()
+{
+	struct ngd_private *priv = NULL;
+	int n = 0;
+	int unit = -1;
+
+AAA
+
+	mtx_assert(&ng_device_mtx, MA_OWNED);
 
-	if (events & (POLLIN | POLLRDNORM)) {
-		/* get the connection we have to know the loc from */
-		SLIST_FOREACH(tmp,&sc->head,links) {
-			if(tmp->ngddev == dev) {
-				connection = tmp;
+	/* When there is no list yet, the first device unit is always 0. */
+	if SLIST_EMPTY(&ngd_nodes)
+		return(0);
+
+	/* Just do a brute force loop to find the first free unit that is
+	 * smaller than MAX_NGD.
+	 * Set MAX_NGD to a large value, doesn't impact performance.
+	 */
+	for(n = 0; n<MAX_NGD && unit == -1; n++) {
+		SLIST_FOREACH(priv, &ngd_nodes, links) {
+
+			if(priv->unit == n) {
+				unit = -1;
+				break;
 			}
+			unit = n;
 		}
-		if(connection == NULL) {
-			printf("%s(): ERROR: connection is still NULL,"
-				"no dev found\n",__func__);
-			return(-1);
-		}
-
-		if (connection->loc > 0)
-			revents |= events & (POLLIN | POLLRDNORM);
 	}
 
-	return(revents);
+	return (unit);
 }
diff --git a/sys/netgraph/ng_device.h b/sys/netgraph/ng_device.h
index 5596134..9f33369 100644
--- a/sys/netgraph/ng_device.h
+++ b/sys/netgraph/ng_device.h
@@ -31,12 +31,19 @@
 
 /* Node type name and magic cookie */
 #define NG_DEVICE_NODE_TYPE	"device"
-#define NGM_DEVICE_COOKIE	1009920473
+#define NGM_DEVICE_COOKIE	1091129178
+#define	NG_DEVICE_DEVNAME	"ngd"
 
+/* Netgraph control messages */
+enum {
+	NGM_DEVICE_GET_DEVNAME,
+};
+
+#if 0
 /* passing ioctl params */
 struct ngd_param_s {
 	        void * p;
 };
-
+#endif
 
 #endif /* _NETGRAPH_NG_DEVICE_H_ */