xref: /dragonfly/sys/netgraph7/netgraph/ng_base.c (revision 79dee9e9)

/*-
 * Copyright (c) 1996-1999 Whistle Communications, Inc.
 * All rights reserved.
 *
 * Subject to the following obligations and disclaimer of warranty, use and
 * redistribution of this software, in source or object code forms, with or
 * without modifications are expressly permitted by Whistle Communications;
 * provided, however, that:
 * 1. Any and all reproductions of the source or object code must include the
 *    copyright notice above and the following disclaimer of warranties; and
 * 2. No rights are granted, in any manner or form, to use Whistle
 *    Communications, Inc. trademarks, including the mark "WHISTLE
 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
 *    such appears in the above copyright notice or in the software.
 *
 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * Authors: Julian Elischer <julian@freebsd.org>
 *          Archie Cobbs <archie@freebsd.org>
 *
 * $FreeBSD: src/sys/netgraph/ng_base.c,v 1.159 2008/04/19 05:30:49 mav Exp $
 * $Whistle: ng_base.c,v 1.39 1999/01/28 23:54:53 julian Exp $
 */

/*
 * This file implements the base netgraph code.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ctype.h>
#include <sys/errno.h>
#include <sys/hash.h>
/*#include <sys/kdb.h>*/
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/msgport2.h>
#include <sys/mutex2.h>
#include <sys/objcache.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/refcount.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <machine/cpu.h>

#include <netgraph7/netgraph.h>
#include <netgraph7/netgraph2.h>
#include <netgraph7/ng_parse.h>

MODULE_VERSION(netgraph, NG_ABI_VERSION);

/* Token to protect topology events. */
static struct lwkt_token	ng_topo_token;
#define	TOPOLOGY_RLOCK()	lwkt_gettoken_shared(&ng_topo_token)
#define	TOPOLOGY_RUNLOCK()	lwkt_reltoken(&ng_topo_token)
#define	TOPOLOGY_WLOCK()	lwkt_gettoken(&ng_topo_token)
#define	TOPOLOGY_WUNLOCK()	lwkt_reltoken(&ng_topo_token)
#define	TOPOLOGY_NOTOWNED()	KKASSERT(!LWKT_TOKEN_HELD_ANY(&ng_topo_token))

#ifdef	NETGRAPH_DEBUG
static struct mtx	ng_nodelist_mtx; /* protects global node/hook lists */
static struct mtx	ngq_mtx;	/* protects the queue item list */

static SLIST_HEAD(, ng_node) ng_allnodes;
static LIST_HEAD(, ng_node) ng_freenodes; /* in debug, we never free() them */
static SLIST_HEAD(, ng_hook) ng_allhooks;
static LIST_HEAD(, ng_hook) ng_freehooks; /* in debug, we never free() them */

static void ng_dumpitems(void);
static void ng_dumpnodes(void);
static void ng_dumphooks(void);

#endif	/* NETGRAPH_DEBUG */
/*
 * DEAD versions of the structures.
 * In order to avoid races, it is sometimes necessary to point
 * at SOMETHING even though theoretically, the current entity is
 * INVALID. Use these to avoid these races.
 */
struct ng_type ng_deadtype = {
	NG_ABI_VERSION,
	"dead",
	NULL,	/* modevent */
	NULL,	/* constructor */
	NULL,	/* rcvmsg */
	NULL,	/* shutdown */
	NULL,	/* newhook */
	NULL,	/* findhook */
	NULL,	/* connect */
	NULL,	/* rcvdata */
	NULL,	/* disconnect */
	NULL, 	/* cmdlist */
};

struct ng_node ng_deadnode = {
	"dead",
	&ng_deadtype,
	NGF_INVALID,
	0,	/* numhooks */
	NULL,	/* private */
	0,	/* ID */
	LIST_HEAD_INITIALIZER(ng_deadnode.hooks),
	{},	/* all_nodes list entry */
	{},	/* id hashtable list entry */
	{
		0,
		NULL,
		0,
		NULL,
	},	/* token */
	1,	/* refs */
#ifdef	NETGRAPH_DEBUG
	ND_MAGIC,
	__FILE__,
	__LINE__,
	{NULL}
#endif	/* NETGRAPH_DEBUG */
};

struct ng_hook ng_deadhook = {
	"dead",
	NULL,		/* private */
	HK_INVALID | HK_DEAD,
	0,		/* undefined data link type */
	&ng_deadhook,	/* Peer is self */
	&ng_deadnode,	/* attached to deadnode */
	{},		/* hooks list */
	NULL,		/* override rcvmsg() */
	NULL,		/* override rcvdata() */
	1,		/* refs always >= 1 */
#ifdef	NETGRAPH_DEBUG
	HK_MAGIC,
	__FILE__,
	__LINE__,
	{NULL}
#endif	/* NETGRAPH_DEBUG */
};

/*
 * END DEAD STRUCTURES
 */

/* We don't want our messages to be replied. This is our panic reply port. */
static struct lwkt_port ng_panic_reply_port;

/* Array of per-CPU target ports */
struct lwkt_port *ng_msgport[MAXCPU];

/* List of installed types */
static LIST_HEAD(, ng_type) ng_typelist;
static struct lwkt_token	ng_typelist_token;
#define	TYPELIST_RLOCK()	lwkt_gettoken_shared(&ng_typelist_token)
#define	TYPELIST_RUNLOCK()	lwkt_reltoken(&ng_typelist_token)
#define	TYPELIST_WLOCK()	lwkt_gettoken(&ng_typelist_token)
#define	TYPELIST_WUNLOCK()	lwkt_reltoken(&ng_typelist_token)

/* Hash related definitions */
LIST_HEAD(nodehash, ng_node);
static struct nodehash		*ng_ID_hash;
static u_long			 ng_ID_hmask;
static u_long			 ng_nodes;
static struct nodehash		*ng_name_hash;
static u_long			 ng_name_hmask;
static u_long			 ng_named_nodes;
static struct lwkt_token	 ng_idhash_token;
#define	IDHASH_RLOCK()		lwkt_gettoken_shared(&ng_idhash_token)
#define	IDHASH_RUNLOCK()	lwkt_reltoken(&ng_idhash_token)
#define	IDHASH_WLOCK()		lwkt_gettoken(&ng_idhash_token)
#define	IDHASH_WUNLOCK()	lwkt_reltoken(&ng_idhash_token)
#define	IDHASH_ASSERT_LOCKED()	KKASSERT(LWKT_TOKEN_HELD_ANY(&ng_idhash_token));
/* Method to find a node.. used twice so do it here */
#define NG_IDHASH_FN(ID) ((ID) % (ng_ID_hmask + 1))
#define NG_IDHASH_FIND(ID, node)					\
	do { 								\
		IDHASH_ASSERT_LOCKED();					\
		LIST_FOREACH(node, &ng_ID_hash[NG_IDHASH_FN(ID)],	\
						nd_idnodes) {		\
			if (NG_NODE_IS_VALID(node)			\
			&& (NG_NODE_ID(node) == ID)) {			\
				break;					\
			}						\
		}							\
	} while (0)

static struct lwkt_token		ng_namehash_token;
#define	NAMEHASH_RLOCK()		lwkt_gettoken_shared(&ng_namehash_token)
#define	NAMEHASH_RUNLOCK()		lwkt_reltoken(&ng_namehash_token)
#define	NAMEHASH_WLOCK()		lwkt_gettoken(&ng_namehash_token)
#define	NAMEHASH_WUNLOCK()		lwkt_reltoken(&ng_namehash_token)
#define	NAMEHASH_ASSERT_LOCKED()	KKASSERT(LWKT_TOKEN_HELD_ANY(&ng_namehash_token));

/* Internal functions */
static int	ng_add_hook(node_p node, const char *name, hook_p * hookp);
static int	ng_generic_msg(node_p here, item_p item, hook_p lasthook);
static ng_ID_t	ng_decodeidname(const char *name);
static int	ngb_mod_event(module_t mod, int event, void *data);
static void	ngthread(void *dummy);
static int	ng_apply_item(item_p item);
static node_p	ng_ID2noderef(ng_ID_t ID);
static int	ng_con_nodes(item_p item, node_p node, const char *name,
		    node_p node2, const char *name2);
static int	ng_con_part2(node_p node, item_p item, hook_p hook);
static int	ng_con_part3(node_p node, item_p item, hook_p hook);
static int	ng_mkpeer(node_p node, const char *name, const char *name2,
		    char *type);
static void	ng_name_rehash(void);
static void	ng_ID_rehash(void);
static boolean_t	bzero_ctor(void *obj, void *private, int ocflags);

/* Imported, these used to be externally visible, some may go back. */
void	ng_destroy_hook(hook_p hook);
node_p	ng_name2noderef(node_p node, const char *name);
int	ng_path2noderef(node_p here, const char *path,
	node_p *dest, hook_p *lasthook);
int	ng_make_node(const char *type, node_p *nodepp);
int	ng_path_parse(char *addr, char **node, char **path, char **hook);
void	ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3);
void	ng_unname(node_p node);


/* Our own netgraph malloc type */
MALLOC_DEFINE(M_NETGRAPH, "netgraph", "netgraph structures and ctrl messages");
MALLOC_DEFINE(M_NETGRAPH_HOOK, "netgraph_hook", "netgraph hook structures");
MALLOC_DEFINE(M_NETGRAPH_NODE, "netgraph_node", "netgraph node structures");
MALLOC_DEFINE(M_NETGRAPH_MSG, "netgraph_msg", "netgraph name storage");
MALLOC_DEFINE(M_NETGRAPH_APPLY, "netgraph_apply", "netgraph apply_info structures");

/* Should not be visible outside this file */

#define _NG_ALLOC_HOOK(hook) \
	hook = kmalloc(sizeof(*hook), M_NETGRAPH_HOOK, \
	    M_WAITOK | M_NULLOK | M_ZERO)
#define _NG_ALLOC_NODE(node) \
	node = kmalloc(sizeof(*node), M_NETGRAPH_NODE, \
	    M_WAITOK | M_NULLOK | M_ZERO)

#ifdef NETGRAPH_DEBUG /*----------------------------------------------*/
/*
 * In debug mode:
 * In an attempt to help track reference count screwups
 * we do not free objects back to the malloc system, but keep them
 * in a local cache where we can examine them and keep information safely
 * after they have been freed.
 * We use this scheme for nodes and hooks, and to some extent for items.
 */
static __inline hook_p
ng_alloc_hook(void)
{
	hook_p hook;
	SLIST_ENTRY(ng_hook) temp;
	mtx_lock(&ng_nodelist_mtx);
	hook = LIST_FIRST(&ng_freehooks);
	if (hook) {
		LIST_REMOVE(hook, hk_hooks);
		bcopy(&hook->hk_all, &temp, sizeof(temp));
		bzero(hook, sizeof(struct ng_hook));
		bcopy(&temp, &hook->hk_all, sizeof(temp));
		mtx_unlock(&ng_nodelist_mtx);
		hook->hk_magic = HK_MAGIC;
	} else {
		mtx_unlock(&ng_nodelist_mtx);
		_NG_ALLOC_HOOK(hook);
		if (hook) {
			hook->hk_magic = HK_MAGIC;
			mtx_lock(&ng_nodelist_mtx);
			SLIST_INSERT_HEAD(&ng_allhooks, hook, hk_all);
			mtx_unlock(&ng_nodelist_mtx);
		}
	}
	return (hook);
}

static __inline node_p
ng_alloc_node(void)
{
	node_p node;
	SLIST_ENTRY(ng_node) temp;
	mtx_lock(&ng_nodelist_mtx);
	node = LIST_FIRST(&ng_freenodes);
	if (node) {
		LIST_REMOVE(node, nd_nodes);
		bcopy(&node->nd_all, &temp, sizeof(temp));
		bzero(node, sizeof(struct ng_node));
		bcopy(&temp, &node->nd_all, sizeof(temp));
		mtx_unlock(&ng_nodelist_mtx);
		node->nd_magic = ND_MAGIC;
	} else {
		mtx_unlock(&ng_nodelist_mtx);
		_NG_ALLOC_NODE(node);
		if (node) {
			node->nd_magic = ND_MAGIC;
			mtx_lock(&ng_nodelist_mtx);
			SLIST_INSERT_HEAD(&ng_allnodes, node, nd_all);
			mtx_unlock(&ng_nodelist_mtx);
		}
	}
	return (node);
}

#define NG_ALLOC_HOOK(hook) do { (hook) = ng_alloc_hook(); } while (0)
#define NG_ALLOC_NODE(node) do { (node) = ng_alloc_node(); } while (0)


#define NG_FREE_HOOK(hook)						\
	do {								\
		mtx_lock(&ng_nodelist_mtx);			\
		LIST_INSERT_HEAD(&ng_freehooks, hook, hk_hooks);	\
		hook->hk_magic = 0;					\
		mtx_unlock(&ng_nodelist_mtx);			\
	} while (0)

#define NG_FREE_NODE(node)						\
	do {								\
		mtx_lock(&ng_nodelist_mtx);			\
		LIST_INSERT_HEAD(&ng_freenodes, node, nd_nodes);	\
		node->nd_magic = 0;					\
		mtx_unlock(&ng_nodelist_mtx);			\
	} while (0)

#else /* NETGRAPH_DEBUG */ /*----------------------------------------------*/

#define NG_ALLOC_HOOK(hook) _NG_ALLOC_HOOK(hook)
#define NG_ALLOC_NODE(node) _NG_ALLOC_NODE(node)

#define NG_FREE_HOOK(hook) do { kfree((hook), M_NETGRAPH_HOOK); } while (0)
#define NG_FREE_NODE(node) do { kfree((node), M_NETGRAPH_NODE); } while (0)

#endif /* NETGRAPH_DEBUG */ /*----------------------------------------------*/

/* Set this to kdb_enter("X") to catch all errors as they occur */
#ifndef TRAP_ERROR
#define TRAP_ERROR()
#endif

static	ng_ID_t nextID = 1;

#ifdef INVARIANTS
#define CHECK_DATA_MBUF(m)	do {					\
		struct mbuf *n;						\
		int total;						\
									\
		M_ASSERTPKTHDR(m);					\
		for (total = 0, n = (m); n != NULL; n = n->m_next) {	\
			total += n->m_len;				\
			if (n->m_nextpkt != NULL)			\
				panic("%s: m_nextpkt", __func__);	\
		}							\
									\
		if ((m)->m_pkthdr.len != total) {			\
			panic("%s: %d != %d",				\
			    __func__, (m)->m_pkthdr.len, total);	\
		}							\
	} while (0)
#else
#define CHECK_DATA_MBUF(m)
#endif

#define ERROUT(x)	do { error = (x); goto done; } while (0)

/************************************************************************
	Parse type definitions for generic messages
************************************************************************/

/* Handy structure parse type defining macro */
#define DEFINE_PARSE_STRUCT_TYPE(lo, up, args)				\
static const struct ng_parse_struct_field				\
	ng_ ## lo ## _type_fields[] = NG_GENERIC_ ## up ## _INFO args;	\
static const struct ng_parse_type ng_generic_ ## lo ## _type = {	\
	&ng_parse_struct_type,						\
	&ng_ ## lo ## _type_fields					\
}

DEFINE_PARSE_STRUCT_TYPE(mkpeer, MKPEER, ());
DEFINE_PARSE_STRUCT_TYPE(connect, CONNECT, ());
DEFINE_PARSE_STRUCT_TYPE(name, NAME, ());
DEFINE_PARSE_STRUCT_TYPE(rmhook, RMHOOK, ());
DEFINE_PARSE_STRUCT_TYPE(nodeinfo, NODEINFO, ());
DEFINE_PARSE_STRUCT_TYPE(typeinfo, TYPEINFO, ());
DEFINE_PARSE_STRUCT_TYPE(linkinfo, LINKINFO, (&ng_generic_nodeinfo_type));

/* Get length of an array when the length is stored as a 32 bit
   value immediately preceding the array -- as with struct namelist
   and struct typelist. */
static int
ng_generic_list_getLength(const struct ng_parse_type *type,
	const u_char *start, const u_char *buf)
{
	return *((const u_int32_t *)(buf - 4));
}

/* Get length of the array of struct linkinfo inside a struct hooklist */
static int
ng_generic_linkinfo_getLength(const struct ng_parse_type *type,
	const u_char *start, const u_char *buf)
{
	const struct hooklist *hl = (const struct hooklist *)start;

	return hl->nodeinfo.hooks;
}

/* Array type for a variable length array of struct namelist */
static const struct ng_parse_array_info ng_nodeinfoarray_type_info = {
	&ng_generic_nodeinfo_type,
	&ng_generic_list_getLength
};
static const struct ng_parse_type ng_generic_nodeinfoarray_type = {
	&ng_parse_array_type,
	&ng_nodeinfoarray_type_info
};

#if 0 /* unused */
/* Array type for a variable length array of struct typelist */
static const struct ng_parse_array_info ng_typeinfoarray_type_info = {
	&ng_generic_typeinfo_type,
	&ng_generic_list_getLength
};
static const struct ng_parse_type ng_generic_typeinfoarray_type = {
	&ng_parse_array_type,
	&ng_typeinfoarray_type_info
};
#endif

/* Array type for array of struct linkinfo in struct hooklist */
static const struct ng_parse_array_info ng_generic_linkinfo_array_type_info = {
	&ng_generic_linkinfo_type,
	&ng_generic_linkinfo_getLength
};
static const struct ng_parse_type ng_generic_linkinfo_array_type = {
	&ng_parse_array_type,
	&ng_generic_linkinfo_array_type_info
};

#if 0 /* unused */
DEFINE_PARSE_STRUCT_TYPE(typelist, TYPELIST, (&ng_generic_typeinfoarray_type));
#endif
DEFINE_PARSE_STRUCT_TYPE(hooklist, HOOKLIST,
	(&ng_generic_nodeinfo_type, &ng_generic_linkinfo_array_type));
DEFINE_PARSE_STRUCT_TYPE(listnodes, LISTNODES,
	(&ng_generic_nodeinfoarray_type));

/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_generic_cmds[] = {
	{
	  NGM_GENERIC_COOKIE,
	  NGM_SHUTDOWN,
	  "shutdown",
	  NULL,
	  NULL
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_MKPEER,
	  "mkpeer",
	  &ng_generic_mkpeer_type,
	  NULL
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_CONNECT,
	  "connect",
	  &ng_generic_connect_type,
	  NULL
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_NAME,
	  "name",
	  &ng_generic_name_type,
	  NULL
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_RMHOOK,
	  "rmhook",
	  &ng_generic_rmhook_type,
	  NULL
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_NODEINFO,
	  "nodeinfo",
	  NULL,
	  &ng_generic_nodeinfo_type
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_LISTHOOKS,
	  "listhooks",
	  NULL,
	  &ng_generic_hooklist_type
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_LISTNAMES,
	  "listnames",
	  NULL,
	  &ng_generic_listnodes_type	/* same as NGM_LISTNODES */
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_LISTNODES,
	  "listnodes",
	  NULL,
	  &ng_generic_listnodes_type
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_LISTTYPES,
	  "listtypes",
	  NULL,
	  &ng_generic_typeinfo_type
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_TEXT_CONFIG,
	  "textconfig",
	  NULL,
	  &ng_parse_string_type
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_TEXT_STATUS,
	  "textstatus",
	  NULL,
	  &ng_parse_string_type
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_ASCII2BINARY,
	  "ascii2binary",
	  &ng_parse_ng_mesg_type,
	  &ng_parse_ng_mesg_type
	},
	{
	  NGM_GENERIC_COOKIE,
	  NGM_BINARY2ASCII,
	  "binary2ascii",
	  &ng_parse_ng_mesg_type,
	  &ng_parse_ng_mesg_type
	},
	{ 0 }
};

/************************************************************************
			Node routines
************************************************************************/

/*
 * Instantiate a node of the requested type
 */
int
ng_make_node(const char *typename, node_p *nodepp)
{
	struct ng_type *type;
	int	error;

	/* Check that the type makes sense */
	if (typename == NULL) {
		TRAP_ERROR();
		return (EINVAL);
	}

	/* Locate the node type. If we fail we return. Do not try to load
	 * module.
	 */
	if ((type = ng_findtype(typename)) == NULL)
		return (ENXIO);

	/*
	 * If we have a constructor, then make the node and
	 * call the constructor to do type specific initialisation.
	 */
	if (type->constructor != NULL) {
		if ((error = ng_make_node_common(type, nodepp)) == 0) {
			if ((error = ((*type->constructor)(*nodepp))) != 0) {
				NG_NODE_UNREF(*nodepp);
			}
		}
	} else {
		/*
		 * Node has no constructor. We cannot ask for one
		 * to be made. It must be brought into existence by
		 * some external agency. The external agency should
		 * call ng_make_node_common() directly to get the
		 * netgraph part initialised.
		 */
		TRAP_ERROR();
		error = EINVAL;
	}
	return (error);
}

/*
 * Generic node creation. Called by node initialisation for externally
 * instantiated nodes (e.g. hardware, sockets, etc ).
 * The returned node has a reference count of 1.
 */
int
ng_make_node_common(struct ng_type *type, node_p *nodepp)
{
	node_p node;

	/* Require the node type to have been already installed */
	if (ng_findtype(type->name) == NULL) {
		TRAP_ERROR();
		return (EINVAL);
	}

	/* Make a node and try attach it to the type */
	NG_ALLOC_NODE(node);
	if (node == NULL) {
		TRAP_ERROR();
		return (ENOMEM);
	}
	node->nd_type = type;
	NG_NODE_REF(node);				/* note reference */
	type->refs++;

	/* Initialize the reader/writer shared token */
	lwkt_token_init(&node->nd_token, type->name);

	/* Initialize hook list for new node */
	LIST_INIT(&node->nd_hooks);

	/* Get an ID and put us in the hash chain. */
	IDHASH_WLOCK();
	for (;;) { /* wrap protection, even if silly */
		node_p node2 = NULL;
		node->nd_ID = nextID++; /* 137/second for 1 year before wrap */

		/* Is there a problem with the new number? */
		NG_IDHASH_FIND(node->nd_ID, node2); /* already taken? */
		if ((node->nd_ID != 0) && (node2 == NULL)) {
			break;
		}
	}
	ng_nodes++;
	if (ng_nodes * 2 > ng_ID_hmask)
		ng_ID_rehash();
	LIST_INSERT_HEAD(&ng_ID_hash[NG_IDHASH_FN(node->nd_ID)], node,
	    nd_idnodes);
	IDHASH_WUNLOCK();

	/* Done */
	*nodepp = node;
	return (0);
}

/*
 * Forceably start the shutdown process on a node. Either call
 * its shutdown method, or do the default shutdown if there is
 * no type-specific method.
 *
 * We can only be called from a shutdown message, so we know we have
 * a writer lock, and therefore exclusive access.
 *
 * Persistent node types must have a type-specific method which
 * allocates a new node in which case, this one is irretrievably going away,
 * or cleans up anything it needs, and just makes the node valid again,
 * in which case we allow the node to survive.
 *
 * XXX We need to think of how to tell a persistent node that we
 * REALLY need to go away because the hardware has gone or we
 * are rebooting.... etc.
 */
void
ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3)
{
	hook_p hook;

	/* Check if it's already shutting down */
	if ((node->nd_flags & NGF_CLOSING) != 0)
		return;

	if (node == &ng_deadnode) {
		kprintf ("shutdown called on deadnode\n");
		return;
	}

	/* Add an extra reference so it doesn't go away during this */
	NG_NODE_REF(node);

	/*
	 * Mark it invalid so any newcomers know not to try use it
	 * Also add our own mark so we can't recurse
	 * note that NGF_INVALID does not do this as it's also set during
	 * creation
	 */
	node->nd_flags |= NGF_INVALID|NGF_CLOSING;

	/* If node has its pre-shutdown method, then call it first*/
	if (node->nd_type && node->nd_type->close)
		(*node->nd_type->close)(node);

	/* Notify all remaining connected nodes to disconnect */
	while ((hook = LIST_FIRST(&node->nd_hooks)) != NULL)
		ng_destroy_hook(hook);

	/* Ask the type if it has anything to do in this case */
	if (node->nd_type && node->nd_type->shutdown) {
		(*node->nd_type->shutdown)(node);
		if (NG_NODE_IS_VALID(node)) {
			/*
			 * Well, blow me down if the node code hasn't declared
			 * that it doesn't want to die.
			 * Presumably it is a persistant node.
			 * If we REALLY want it to go away,
			 *  e.g. hardware going away,
			 * Our caller should set NGF_REALLY_DIE in nd_flags.
			 */
			node->nd_flags &= ~(NGF_INVALID|NGF_CLOSING);
			NG_NODE_UNREF(node); /* Assume they still have theirs */
			return;
		}
	} else {				/* do the default thing */
		NG_NODE_UNREF(node);
	}

	ng_unname(node); /* basically a NOP these days */

	/*
	 * Remove extra reference, possibly the last
	 * Possible other holders of references may include
	 * timeout callouts, but theoretically the node's supposed to
	 * have cancelled them. Possibly hardware dependencies may
	 * force a driver to 'linger' with a reference.
	 */
	NG_NODE_UNREF(node);
}

/*
 * Remove a reference to the node, possibly the last.
 * deadnode always acts as it it were the last.
 */
void
ng_unref_node(node_p node)
{

	if (node == &ng_deadnode)
		return;

	if (refcount_release(&node->nd_refs)) { /* we were the last */

		node->nd_type->refs--; /* XXX maybe should get types lock? */
		NAMEHASH_WLOCK();
		if (NG_NODE_HAS_NAME(node)) {
			ng_named_nodes--;
			LIST_REMOVE(node, nd_nodes);
		}
		NAMEHASH_WUNLOCK();

		IDHASH_WLOCK();
		ng_nodes--;
		LIST_REMOVE(node, nd_idnodes);
		IDHASH_WUNLOCK();

		NG_FREE_NODE(node);
	}
}

/************************************************************************
			Node ID handling
************************************************************************/
static node_p
ng_ID2noderef(ng_ID_t ID)
{
	node_p node;

	IDHASH_RLOCK();
	NG_IDHASH_FIND(ID, node);
	if (node)
		NG_NODE_REF(node);
	IDHASH_RUNLOCK();
	return(node);
}

ng_ID_t
ng_node2ID(node_p node)
{
	return (node ? NG_NODE_ID(node) : 0);
}

/************************************************************************
			Node name handling
************************************************************************/

/*
 * Assign a node a name.
 */
int
ng_name_node(node_p node, const char *name)
{
	uint32_t hash;
	node_p node2;
	int i;

	/* Check the name is valid */
	for (i = 0; i < NG_NODESIZ; i++) {
		if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
			break;
	}
	if (i == 0 || name[i] != '\0') {
		TRAP_ERROR();
		return (EINVAL);
	}
	if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
		TRAP_ERROR();
		return (EINVAL);
	}

	NAMEHASH_WLOCK();
	if (ng_named_nodes * 2 > ng_name_hmask)
		ng_name_rehash();

	hash = hash32_str(name, HASHINIT) & ng_name_hmask;
	/* Check the name isn't already being used. */
	LIST_FOREACH(node2, &ng_name_hash[hash], nd_nodes)
		if (NG_NODE_IS_VALID(node2) &&
		    (strcmp(NG_NODE_NAME(node2), name) == 0)) {
			NAMEHASH_WUNLOCK();
			return (EADDRINUSE);
		}

	if (NG_NODE_HAS_NAME(node))
		LIST_REMOVE(node, nd_nodes);
	else
		ng_named_nodes++;
	/* Copy it. */
	strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);

	/* Update name hash. */
	LIST_INSERT_HEAD(&ng_name_hash[hash], node, nd_nodes);
	NAMEHASH_WUNLOCK();

	return (0);
}

/*
 * Find a node by absolute name. The name should NOT end with ':'
 * The name "." means "this node" and "[xxx]" means "the node
 * with ID (ie, at address) xxx".
 *
 * Returns the node if found, else NULL.
 * Eventually should add something faster than a sequential search.
 * Note it acquires a reference on the node so you can be sure it's still
 * there.
 */
node_p
ng_name2noderef(node_p here, const char *name)
{
	node_p node;
	ng_ID_t temp;
	int	hash;

	/* "." means "this node" */
	if (strcmp(name, ".") == 0) {
		NG_NODE_REF(here);
		return(here);
	}

	/* Check for name-by-ID */
	if ((temp = ng_decodeidname(name)) != 0) {
		return (ng_ID2noderef(temp));
	}

	/* Find node by name. */
	hash = hash32_str(name, HASHINIT) & ng_name_hmask;
	NAMEHASH_RLOCK();
	LIST_FOREACH(node, &ng_name_hash[hash], nd_nodes)
		if (NG_NODE_IS_VALID(node) &&
		    (strcmp(NG_NODE_NAME(node), name) == 0)) {
			NG_NODE_REF(node);
			break;
		}
	NAMEHASH_RUNLOCK();

	return (node);
}

/*
 * Decode an ID name, eg. "[f03034de]". Returns 0 if the
 * string is not valid, otherwise returns the value.
 */
static ng_ID_t
ng_decodeidname(const char *name)
{
	const int len = strlen(name);
	char *eptr;
	u_long val;

	/* Check for proper length, brackets, no leading junk */
	if ((len < 3)
	|| (name[0] != '[')
	|| (name[len - 1] != ']')
	|| (!isxdigit(name[1]))) {
		return ((ng_ID_t)0);
	}

	/* Decode number */
	val = strtoul(name + 1, &eptr, 16);
	if ((eptr - name != len - 1)
	|| (val == ULONG_MAX)
	|| (val == 0)) {
		return ((ng_ID_t)0);
	}
	return (ng_ID_t)val;
}

/*
 * Remove a name from a node. This should only be called
 * when shutting down and removing the node.
 */
void
ng_unname(node_p node)
{
}

/*
 * Allocate a bigger name hash.
 */
static void
ng_name_rehash(void)
{
	struct nodehash *new;
	uint32_t hash;
	u_long hmask;
	node_p node, node2;
	int i;

	NAMEHASH_ASSERT_LOCKED();
	new = hashinit((ng_name_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask);
	if (new == NULL)
		return;

	for (i = 0; i <= ng_name_hmask; i++) {
		LIST_FOREACH_MUTABLE(node, &ng_name_hash[i], nd_nodes, node2) {
#ifdef INVARIANTS
			LIST_REMOVE(node, nd_nodes);
#endif
			hash = hash32_str(NG_NODE_NAME(node), HASHINIT) & hmask;
			LIST_INSERT_HEAD(&new[hash], node, nd_nodes);
		}
	}

	hashdestroy(ng_name_hash, M_NETGRAPH_NODE, ng_name_hmask);
	ng_name_hash = new;
	ng_name_hmask = hmask;
}

/*
 * Allocate a bigger ID hash.
 */
static void
ng_ID_rehash(void)
{
	struct nodehash *new;
	uint32_t hash;
	u_long hmask;
	node_p node, node2;
	int i;

	IDHASH_ASSERT_LOCKED();
	new = hashinit((ng_ID_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask);
	if (new == NULL)
		return;

	for (i = 0; i <= ng_ID_hmask; i++) {
		LIST_FOREACH_MUTABLE(node, &ng_ID_hash[i], nd_idnodes, node2) {
#ifdef INVARIANTS
			LIST_REMOVE(node, nd_idnodes);
#endif
			hash = (node->nd_ID % (hmask + 1));
			LIST_INSERT_HEAD(&new[hash], node, nd_idnodes);
		}
	}

	hashdestroy(ng_ID_hash, M_NETGRAPH_NODE, ng_name_hmask);
	ng_ID_hash = new;
	ng_ID_hmask = hmask;
}

/************************************************************************
			Hook routines
 Names are not optional. Hooks are always connected, except for a
 brief moment within these routines. On invalidation or during creation
 they are connected to the 'dead' hook.
************************************************************************/

/*
 * Remove a hook reference
 */
void
ng_unref_hook(hook_p hook)
{
	int v;

	if (hook == &ng_deadhook) {
		return;
	}

	v = atomic_fetchadd_int(&hook->hk_refs, -1);

	if (v == 1) { /* we were the last */
		if (_NG_HOOK_NODE(hook)) /* it'll probably be ng_deadnode */
			_NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
		NG_FREE_HOOK(hook);
	}
}

/*
 * Add an unconnected hook to a node. Only used internally.
 * Assumes node is locked. (XXX not yet true )
 */
static int
ng_add_hook(node_p node, const char *name, hook_p *hookp)
{
	hook_p hook;
	int error = 0;

	/* Check that the given name is good */
	if (name == NULL) {
		TRAP_ERROR();
		return (EINVAL);
	}
	if (ng_findhook(node, name) != NULL) {
		TRAP_ERROR();
		return (EEXIST);
	}

	/* Allocate the hook and link it up */
	NG_ALLOC_HOOK(hook);
	if (hook == NULL) {
		TRAP_ERROR();
		return (ENOMEM);
	}
	hook->hk_refs = 1;		/* add a reference for us to return */
	hook->hk_flags = HK_INVALID;
	hook->hk_peer = &ng_deadhook;	/* start off this way */
	hook->hk_node = node;
	NG_NODE_REF(node);		/* each hook counts as a reference */

	/* Set hook name */
	strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);

	/*
	 * Check if the node type code has something to say about it
	 * If it fails, the unref of the hook will also unref the node.
	 */
	if (node->nd_type->newhook != NULL) {
		if ((error = (*node->nd_type->newhook)(node, hook, name))) {
			NG_HOOK_UNREF(hook);	/* this frees the hook */
			return (error);
		}
	}
	/*
	 * The 'type' agrees so far, so go ahead and link it in.
	 * We'll ask again later when we actually connect the hooks.
	 */
	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
	node->nd_numhooks++;
	NG_HOOK_REF(hook);	/* one for the node */

	if (hookp)
		*hookp = hook;
	return (0);
}

/*
 * Find a hook
 *
 * Node types may supply their own optimized routines for finding
 * hooks.  If none is supplied, we just do a linear search.
 * XXX Possibly we should add a reference to the hook?
 */
hook_p
ng_findhook(node_p node, const char *name)
{
	hook_p hook;

	if (node->nd_type->findhook != NULL)
		return (*node->nd_type->findhook)(node, name);
	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
		if (NG_HOOK_IS_VALID(hook)
		&& (strcmp(NG_HOOK_NAME(hook), name) == 0))
			return (hook);
	}
	return (NULL);
}

/*
 * Destroy a hook
 *
 * As hooks are always attached, this really destroys two hooks.
 * The one given, and the one attached to it. Disconnect the hooks
 * from each other first. We reconnect the peer hook to the 'dead'
 * hook so that it can still exist after we depart. We then
 * send the peer its own destroy message. This ensures that we only
 * interact with the peer's structures when it is locked processing that
 * message. We hold a reference to the peer hook so we are guaranteed that
 * the peer hook and node are still going to exist until
 * we are finished there as the hook holds a ref on the node.
 * We run this same code again on the peer hook, but that time it is already
 * attached to the 'dead' hook.
 *
 * This routine is called at all stages of hook creation
 * on error detection and must be able to handle any such stage.
 */
void
ng_destroy_hook(hook_p hook)
{
	hook_p peer;
	node_p node;

	if (hook == &ng_deadhook) {	/* better safe than sorry */
		kprintf("ng_destroy_hook called on deadhook\n");
		return;
	}

	/*
	 * Protect divorce process with mutex, to avoid races on
	 * simultaneous disconnect.
	 */
	TOPOLOGY_WLOCK();

	hook->hk_flags |= HK_INVALID;

	peer = NG_HOOK_PEER(hook);
	node = NG_HOOK_NODE(hook);

	if (peer && (peer != &ng_deadhook)) {
		/*
		 * Set the peer to point to ng_deadhook
		 * from this moment on we are effectively independent it.
		 * send it an rmhook message of it's own.
		 */
		peer->hk_peer = &ng_deadhook;	/* They no longer know us */
		hook->hk_peer = &ng_deadhook;	/* Nor us, them */
		if (NG_HOOK_NODE(peer) == &ng_deadnode) {
			/*
			 * If it's already divorced from a node,
			 * just free it.
			 */
			TOPOLOGY_WUNLOCK();
		} else {
			TOPOLOGY_WUNLOCK();
			ng_rmhook_self(peer); 	/* Send it a surprise */
		}
		NG_HOOK_UNREF(peer);		/* account for peer link */
		NG_HOOK_UNREF(hook);		/* account for peer link */
	} else
		TOPOLOGY_WUNLOCK();

	TOPOLOGY_NOTOWNED();

	/*
	 * Remove the hook from the node's list to avoid possible recursion
	 * in case the disconnection results in node shutdown.
	 */
	if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
		return;
	}
	LIST_REMOVE(hook, hk_hooks);
	node->nd_numhooks--;
	if (node->nd_type->disconnect) {
		/*
		 * The type handler may elect to destroy the node so don't
		 * trust its existence after this point. (except
		 * that we still hold a reference on it. (which we
		 * inherrited from the hook we are destroying)
		 */
		(*node->nd_type->disconnect) (hook);
	}

	/*
	 * Note that because we will point to ng_deadnode, the original node
	 * is not decremented automatically so we do that manually.
	 */
	_NG_HOOK_NODE(hook) = &ng_deadnode;
	NG_NODE_UNREF(node);	/* We no longer point to it so adjust count */
	NG_HOOK_UNREF(hook);	/* Account for linkage (in list) to node */
}

/*
 * Take two hooks on a node and merge the connection so that the given node
 * is effectively bypassed.
 */
int
ng_bypass(hook_p hook1, hook_p hook2)
{
	if (hook1->hk_node != hook2->hk_node) {
		TRAP_ERROR();
		return (EINVAL);
	}
	hook1->hk_peer->hk_peer = hook2->hk_peer;
	hook2->hk_peer->hk_peer = hook1->hk_peer;

	hook1->hk_peer = &ng_deadhook;
	hook2->hk_peer = &ng_deadhook;

	NG_HOOK_UNREF(hook1);
	NG_HOOK_UNREF(hook2);

	/* XXX If we ever cache methods on hooks update them as well */
	ng_destroy_hook(hook1);
	ng_destroy_hook(hook2);
	return (0);
}

/*
 * Install a new netgraph type
 */
int
ng_newtype(struct ng_type *tp)
{
	const size_t namelen = strlen(tp->name);

	/* Check version and type name fields */
	if ((tp->version != NG_ABI_VERSION)
	|| (namelen == 0)
	|| (namelen >= NG_TYPESIZ)) {
		TRAP_ERROR();
		if (tp->version != NG_ABI_VERSION) {
			kprintf("Netgraph: Node type rejected. ABI mismatch. Suggest recompile\n");
		}
		return (EINVAL);
	}

	/* Check for name collision */
	if (ng_findtype(tp->name) != NULL) {
		TRAP_ERROR();
		return (EEXIST);
	}

	/* Link in new type */
	TYPELIST_WLOCK();
	LIST_INSERT_HEAD(&ng_typelist, tp, types);
	tp->refs = 1;	/* first ref is linked list */
	TYPELIST_WUNLOCK();
	return (0);
}

/*
 * unlink a netgraph type
 * If no examples exist
 */
int
ng_rmtype(struct ng_type *tp)
{
	/* Check for name collision */
	if (tp->refs != 1) {
		TRAP_ERROR();
		return (EBUSY);
	}

	/* Unlink type */
	TYPELIST_WLOCK();
	LIST_REMOVE(tp, types);
	TYPELIST_WUNLOCK();
	return (0);
}

/*
 * Look for a type of the name given
 */
struct ng_type *
ng_findtype(const char *typename)
{
	struct ng_type *type;

	TYPELIST_RLOCK();
	LIST_FOREACH(type, &ng_typelist, types) {
		if (strcmp(type->name, typename) == 0)
			break;
	}
	TYPELIST_RUNLOCK();
	return (type);
}

/************************************************************************
			Composite routines
************************************************************************/
/*
 * Connect two nodes using the specified hooks, using queued functions.
 */
static int
ng_con_part3(node_p node, item_p item, hook_p hook)
{
	int	error = 0;

	/*
	 * When we run, we know that the node 'node' is locked for us.
	 * Our caller has a reference on the hook.
	 * Our caller has a reference on the node.
	 * (In this case our caller is ng_apply_item() ).
	 * The peer hook has a reference on the hook.
	 * We are all set up except for the final call to the node, and
	 * the clearing of the INVALID flag.
	 */
	if (NG_HOOK_NODE(hook) == &ng_deadnode) {
		/*
		 * The node must have been freed again since we last visited
		 * here. ng_destry_hook() has this effect but nothing else does.
		 * We should just release our references and
		 * free anything we can think of.
		 * Since we know it's been destroyed, and it's our caller
		 * that holds the references, just return.
		 */
		ERROUT(ENOENT);
	}
	if (hook->hk_node->nd_type->connect) {
		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
			ng_destroy_hook(hook);	/* also zaps peer */
			kprintf("failed in ng_con_part3()\n");
			ERROUT(error);
		}
	}
	/*
	 *  XXX this is wrong for SMP. Possibly we need
	 * to separate out 'create' and 'invalid' flags.
	 * should only set flags on hooks we have locked under our node.
	 */
	hook->hk_flags &= ~HK_INVALID;
done:
	NG_FREE_ITEM(item);
	return (error);
}

static int
ng_con_part2(node_p node, item_p item, hook_p hook)
{
	hook_p	peer;
	int	error = 0;

	/*
	 * When we run, we know that the node 'node' is locked for us.
	 * Our caller has a reference on the hook.
	 * Our caller has a reference on the node.
	 * (In this case our caller is ng_apply_item() ).
	 * The peer hook has a reference on the hook.
	 * our node pointer points to the 'dead' node.
	 * First check the hook name is unique.
	 * Should not happen because we checked before queueing this.
	 */
	if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
		TRAP_ERROR();
		ng_destroy_hook(hook); /* should destroy peer too */
		kprintf("failed in ng_con_part2()\n");
		ERROUT(EEXIST);
	}
	/*
	 * Check if the node type code has something to say about it
	 * If it fails, the unref of the hook will also unref the attached node,
	 * however since that node is 'ng_deadnode' this will do nothing.
	 * The peer hook will also be destroyed.
	 */
	if (node->nd_type->newhook != NULL) {
		if ((error = (*node->nd_type->newhook)(node, hook,
		    hook->hk_name))) {
			ng_destroy_hook(hook); /* should destroy peer too */
			kprintf("failed in ng_con_part2()\n");
			ERROUT(error);
		}
	}

	/*
	 * The 'type' agrees so far, so go ahead and link it in.
	 * We'll ask again later when we actually connect the hooks.
	 */
	hook->hk_node = node;		/* just overwrite ng_deadnode */
	NG_NODE_REF(node);		/* each hook counts as a reference */
	LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
	node->nd_numhooks++;
	NG_HOOK_REF(hook);	/* one for the node */

	/*
	 * We now have a symmetrical situation, where both hooks have been
	 * linked to their nodes, the newhook methods have been called
	 * And the references are all correct. The hooks are still marked
	 * as invalid, as we have not called the 'connect' methods
	 * yet.
	 * We can call the local one immediately as we have the
	 * node locked, but we need to queue the remote one.
	 */
	if (hook->hk_node->nd_type->connect) {
		if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
			ng_destroy_hook(hook);	/* also zaps peer */
			kprintf("failed in ng_con_part2(A)\n");
			ERROUT(error);
		}
	}

	/*
	 * Acquire topo token to avoid race with ng_destroy_hook().
	 */
	TOPOLOGY_RLOCK();
	peer = hook->hk_peer;
	if (peer == &ng_deadhook) {
		TOPOLOGY_RUNLOCK();
		kprintf("failed in ng_con_part2(B)\n");
		ng_destroy_hook(hook);
		ERROUT(ENOENT);
	}
	TOPOLOGY_RUNLOCK();

	if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
	    NULL, 0, NG_REUSE_ITEM))) {
		kprintf("failed in ng_con_part2(C)\n");
		ng_destroy_hook(hook);	/* also zaps peer */
		return (error);		/* item was consumed. */
	}
	hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
	return (0);			/* item was consumed. */
done:
	NG_FREE_ITEM(item);
	return (error);
}

/*
 * Connect this node with another node. We assume that this node is
 * currently locked, as we are only called from an NGM_CONNECT message.
 */
static int
ng_con_nodes(item_p item, node_p node, const char *name,
    node_p node2, const char *name2)
{
	int	error;
	hook_p	hook;
	hook_p	hook2;

	if (ng_findhook(node2, name2) != NULL) {
		return(EEXIST);
	}
	if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
		return (error);
	/* Allocate the other hook and link it up */
	NG_ALLOC_HOOK(hook2);
	if (hook2 == NULL) {
		TRAP_ERROR();
		ng_destroy_hook(hook);	/* XXX check ref counts so far */
		NG_HOOK_UNREF(hook);	/* including our ref */
		return (ENOMEM);
	}
	hook2->hk_refs = 1;		/* start with a reference for us. */
	hook2->hk_flags = HK_INVALID;
	hook2->hk_peer = hook;		/* Link the two together */
	hook->hk_peer = hook2;
	NG_HOOK_REF(hook);		/* Add a ref for the peer to each*/
	NG_HOOK_REF(hook2);
	hook2->hk_node = &ng_deadnode;
	strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);

	/*
	 * Queue the function above.
	 * Procesing continues in that function in the lock context of
	 * the other node.
	 */
	if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
	    NG_NOFLAGS))) {
		kprintf("failed in ng_con_nodes(): %d\n", error);
		ng_destroy_hook(hook);	/* also zaps peer */
	}

	NG_HOOK_UNREF(hook);		/* Let each hook go if it wants to */
	NG_HOOK_UNREF(hook2);
	return (error);
}

/*
 * Make a peer and connect.
 * We assume that the local node is locked.
 * The new node probably doesn't need a lock until
 * it has a hook, because it cannot really have any work until then,
 * but we should think about it a bit more.
 *
 * The problem may come if the other node also fires up
 * some hardware or a timer or some other source of activation,
 * also it may already get a command msg via it's ID.
 *
 * We could use the same method as ng_con_nodes() but we'd have
 * to add ability to remove the node when failing. (Not hard, just
 * make arg1 point to the node to remove).
 * Unless of course we just ignore failure to connect and leave
 * an unconnected node?
 */
static int
ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
{
	node_p	node2;
	hook_p	hook1, hook2;
	int	error;

	if ((error = ng_make_node(type, &node2))) {
		return (error);
	}

	if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
		ng_rmnode(node2, NULL, NULL, 0);
		return (error);
	}

	if ((error = ng_add_hook(node2, name2, &hook2))) {
		ng_rmnode(node2, NULL, NULL, 0);
		ng_destroy_hook(hook1);
		NG_HOOK_UNREF(hook1);
		return (error);
	}

	/*
	 * Actually link the two hooks together.
	 */
	hook1->hk_peer = hook2;
	hook2->hk_peer = hook1;

	/* Each hook is referenced by the other */
	NG_HOOK_REF(hook1);
	NG_HOOK_REF(hook2);

	/* Give each node the opportunity to veto the pending connection */
	if (hook1->hk_node->nd_type->connect) {
		error = (*hook1->hk_node->nd_type->connect) (hook1);
	}

	if ((error == 0) && hook2->hk_node->nd_type->connect) {
		error = (*hook2->hk_node->nd_type->connect) (hook2);

	}

	/*
	 * drop the references we were holding on the two hooks.
	 */
	if (error) {
		ng_destroy_hook(hook2);	/* also zaps hook1 */
		ng_rmnode(node2, NULL, NULL, 0);
	} else {
		/* As a last act, allow the hooks to be used */
		hook1->hk_flags &= ~HK_INVALID;
		hook2->hk_flags &= ~HK_INVALID;
	}
	NG_HOOK_UNREF(hook1);
	NG_HOOK_UNREF(hook2);
	return (error);
}

/************************************************************************
		Utility routines to send self messages
************************************************************************/

/* Shut this node down as soon as everyone is clear of it */
/* Should add arg "immediately" to jump the queue */
int
ng_rmnode_self(node_p node)
{
	int		error;

	if (node == &ng_deadnode)
		return (0);
	node->nd_flags |= NGF_INVALID;
	if (node->nd_flags & NGF_CLOSING)
		return (0);

	error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
	return (error);
}

static void
ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
{
	ng_destroy_hook(hook);
	return ;
}

int
ng_rmhook_self(hook_p hook)
{
	int		error;
	node_p node = NG_HOOK_NODE(hook);

	if (node == &ng_deadnode)
		return (0);

	error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
	return (error);
}

/***********************************************************************
 * Parse and verify a string of the form:  <NODE:><PATH>
 *
 * Such a string can refer to a specific node or a specific hook
 * on a specific node, depending on how you look at it. In the
 * latter case, the PATH component must not end in a dot.
 *
 * Both <NODE:> and <PATH> are optional. The <PATH> is a string
 * of hook names separated by dots. This breaks out the original
 * string, setting *nodep to "NODE" (or NULL if none) and *pathp
 * to "PATH" (or NULL if degenerate). Also, *hookp will point to
 * the final hook component of <PATH>, if any, otherwise NULL.
 *
 * This returns -1 if the path is malformed. The char ** are optional.
 ***********************************************************************/
int
ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
{
	char	*node, *path, *hook;
	int	k;

	/*
	 * Extract absolute NODE, if any
	 */
	for (path = addr; *path && *path != ':'; path++);
	if (*path) {
		node = addr;	/* Here's the NODE */
		*path++ = '\0';	/* Here's the PATH */

		/* Node name must not be empty */
		if (!*node)
			return -1;

		/* A name of "." is OK; otherwise '.' not allowed */
		if (strcmp(node, ".") != 0) {
			for (k = 0; node[k]; k++)
				if (node[k] == '.')
					return -1;
		}
	} else {
		node = NULL;	/* No absolute NODE */
		path = addr;	/* Here's the PATH */
	}

	/* Snoop for illegal characters in PATH */
	for (k = 0; path[k]; k++)
		if (path[k] == ':')
			return -1;

	/* Check for no repeated dots in PATH */
	for (k = 0; path[k]; k++)
		if (path[k] == '.' && path[k + 1] == '.')
			return -1;

	/* Remove extra (degenerate) dots from beginning or end of PATH */
	if (path[0] == '.')
		path++;
	if (*path && path[strlen(path) - 1] == '.')
		path[strlen(path) - 1] = 0;

	/* If PATH has a dot, then we're not talking about a hook */
	if (*path) {
		for (hook = path, k = 0; path[k]; k++)
			if (path[k] == '.') {
				hook = NULL;
				break;
			}
	} else
		path = hook = NULL;

	/* Done */
	if (nodep)
		*nodep = node;
	if (pathp)
		*pathp = path;
	if (hookp)
		*hookp = hook;
	return (0);
}

/*
 * Given a path, which may be absolute or relative, and a starting node,
 * return the destination node.
 */
int
ng_path2noderef(node_p here, const char *address,
				node_p *destp, hook_p *lasthook)
{
	char    fullpath[NG_PATHSIZ];
	char   *nodename, *path, pbuf[2];
	node_p  node, oldnode;
	char   *cp;
	hook_p hook = NULL;

	/* Initialize */
	if (destp == NULL) {
		TRAP_ERROR();
		return EINVAL;
	}
	*destp = NULL;

	/* Make a writable copy of address for ng_path_parse() */
	strncpy(fullpath, address, sizeof(fullpath) - 1);
	fullpath[sizeof(fullpath) - 1] = '\0';

	/* Parse out node and sequence of hooks */
	if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
		TRAP_ERROR();
		return EINVAL;
	}
	if (path == NULL) {
		pbuf[0] = '.';	/* Needs to be writable */
		pbuf[1] = '\0';
		path = pbuf;
	}

	/*
	 * For an absolute address, jump to the starting node.
	 * Note that this holds a reference on the node for us.
	 * Don't forget to drop the reference if we don't need it.
	 */
	if (nodename) {
		node = ng_name2noderef(here, nodename);
		if (node == NULL) {
			TRAP_ERROR();
			return (ENOENT);
		}
	} else {
		if (here == NULL) {
			TRAP_ERROR();
			return (EINVAL);
		}
		node = here;
		NG_NODE_REF(node);
	}

	/*
	 * Now follow the sequence of hooks
	 * XXX
	 * We actually cannot guarantee that the sequence
	 * is not being demolished as we crawl along it
	 * without extra-ordinary locking etc.
	 * So this is a bit dodgy to say the least.
	 * We can probably hold up some things by holding
	 * the nodelist mutex for the time of this
	 * crawl if we wanted.. At least that way we wouldn't have to
	 * worry about the nodes disappearing, but the hooks would still
	 * be a problem.
	 */
	for (cp = path; node != NULL && *cp != '\0'; ) {
		char *segment;

		/*
		 * Break out the next path segment. Replace the dot we just
		 * found with a NUL; "cp" points to the next segment (or the
		 * NUL at the end).
		 */
		for (segment = cp; *cp != '\0'; cp++) {
			if (*cp == '.') {
				*cp++ = '\0';
				break;
			}
		}

		/* Empty segment */
		if (*segment == '\0')
			continue;

		/* We have a segment, so look for a hook by that name */
		hook = ng_findhook(node, segment);

		/* Can't get there from here... */
		if (hook == NULL
		    || NG_HOOK_PEER(hook) == NULL
		    || NG_HOOK_NOT_VALID(hook)
		    || NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
			TRAP_ERROR();
			NG_NODE_UNREF(node);
#if 0
			kprintf("hooknotvalid %s %s %d %d %d %d ",
					path,
					segment,
					hook == NULL,
					NG_HOOK_PEER(hook) == NULL,
					NG_HOOK_NOT_VALID(hook),
					NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook)));
#endif
			return (ENOENT);
		}

		/*
		 * Hop on over to the next node
		 * XXX
		 * Big race conditions here as hooks and nodes go away
		 * *** Idea.. store an ng_ID_t in each hook and use that
		 * instead of the direct hook in this crawl?
		 */
		oldnode = node;
		if ((node = NG_PEER_NODE(hook)))
			NG_NODE_REF(node);	/* XXX RACE */
		NG_NODE_UNREF(oldnode);	/* XXX another race */
		if (NG_NODE_NOT_VALID(node)) {
			NG_NODE_UNREF(node);	/* XXX more races */
			node = NULL;
		}
	}

	/* If node somehow missing, fail here (probably this is not needed) */
	if (node == NULL) {
		TRAP_ERROR();
		return (ENXIO);
	}

	/* Done */
	*destp = node;
	if (lasthook != NULL)
		*lasthook = (hook ? NG_HOOK_PEER(hook) : NULL);
	return (0);
}

/*********************************************************************\
* Inter-CPU node synchronization
*
* All activities are submitted to one of the netgraph per-CPU threads.
* There is one item input queue per CPU, not one per node as in
* FreeBSD.  If the item is entering netgraph for the first time, it is
* queued to the thread's msgport.  Otherwise it is applied directly.
* From start to finish, the item is processed on the same CPU.  Items
* are distributed based on the ingress node, to keep item ordering.
\***************************************************************/

static __inline void	ng_acquire_read(node_p node);
static __inline void	ng_acquire_write(node_p node);
static __inline void	ng_leave_readwrite(node_p node);

static __inline void
ng_acquire_read(node_p node)
{
	KASSERT(node != &ng_deadnode,
	    ("%s: working on deadnode", __func__));

	lwkt_gettoken_shared(&node->nd_token);
}

/* Acquire writer lock on node. If node is busy, sleep. */
static __inline void
ng_acquire_write(node_p node)
{
	KASSERT(node != &ng_deadnode,
	    ("%s: working on deadnode", __func__));

	lwkt_gettoken(&node->nd_token);
}

/* Release reader or writer lock. */
static __inline void
ng_leave_readwrite(node_p node)
{
	lwkt_reltoken(&node->nd_token);
}

/***********************************************************************
* Worklist routines
**********************************************************************/
/* NETGRAPH thread routine
 *
 * Pick an item from our thread's queue and apply it.
 */
static void
ngthread(void *dummy __unused)
{
	lwkt_msg_t msg;

	while ((msg = lwkt_waitport(&curthread->td_msgport, 0)) != NULL) {
		item_p  item = (void *)msg;

		ng_apply_item(item);
		/* Do not reply to the message */
	}
}

/***********************************************************************
* Externally visible method for sending or queueing messages or data.
***********************************************************************/

/*
 * The module code should have filled out the item correctly by this stage:
 * Common:
 *    reference to destination node.
 *    Reference to destination rcv hook if relevant.
 *    apply pointer must be or NULL or reference valid struct ng_apply_info.
 * Data:
 *    pointer to mbuf
 * Control_Message:
 *    pointer to msg.
 *    ID of original sender node. (return address)
 * Function:
 *    Function pointer
 *    void * argument
 *    integer argument
 *
 * The nodes have several routines and macros to help with this task:
 */

int
ng_snd_item(item_p item, int flags)
{
	hook_p hook;
	node_p node;
	int error = 0;

	/* We are sending item, so it must be present! */
	KASSERT(item != NULL, ("ng_snd_item: item is NULL"));

#ifdef	NETGRAPH_DEBUG
	_ngi_check(item, __FILE__, __LINE__);
#endif

	/*
	 * Every time an item is sent or forwarded we hold a reference on it
	 * to postone the callback (if there is one) and item freedom.
	 */
	ng_ref_item(item);

	/*
	 * Node is never optional.
	 */
	node = NGI_NODE(item);
	KASSERT(node != NULL, ("ng_snd_item: node is NULL"));

	/*
	 * Valid hook and mbuf are mandatory for data.
	 */
	hook = NGI_HOOK(item);
	if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
		KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
		if (NGI_M(item) == NULL)
			ERROUT(EINVAL);
		CHECK_DATA_MBUF(NGI_M(item));
	}

	/*
	 * Always queue items entering netgraph for the first time.
	 */
	if (item->refs == 1) {
		struct lwkt_msg *msg = &item->el_lmsg;

		lwkt_initmsg(msg, &ng_panic_reply_port, 0);
		/* Always send to cpu0 for now */
		lwkt_sendmsg(ng_cpuport(0), msg);

		return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
	}

	/*
	 * The item wasn't queued.  Process it synchronously.
	 */
	error = ng_apply_item(item);

done:
	return (error);
}

/*
 * We have an item that was possibly queued somewhere.
 * It should contain all the information needed
 * to run it on the appropriate node/hook.
 * If there is apply pointer and we own the last reference, call apply().
 */
static int
ng_apply_item(item_p item)
{
	hook_p  hook;
	node_p	node;
	ng_rcvdata_t *rcvdata;
	ng_rcvmsg_t *rcvmsg;
	int	error = 0;

	/* Node and item are never optional. */
	KASSERT(item != NULL, ("ng_apply_item: item is NULL"));
	NGI_GET_NODE(item, node);		/* zaps stored node */
	KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
	NGI_GET_HOOK(item, hook);		/* clears stored hook */

	/*
	 * If the item or the node specifies single threading, force
	 * writer semantics. Similarly, the node may say one hook always
	 * produces writers. These are overrides.
	 */
	if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
	    (node->nd_flags & NGF_FORCE_WRITER) ||
	    (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
		ng_acquire_write(node);
	} else {
		ng_acquire_read(node);
	}

#ifdef	NETGRAPH_DEBUG
	_ngi_check(item, __FILE__, __LINE__);
#endif

	switch (item->el_flags & NGQF_TYPE) {
	case NGQF_DATA:
		/*
		 * Check things are still ok as when we were queued.
		 */
		KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
		if (NG_HOOK_NOT_VALID(hook) ||
		    NG_NODE_NOT_VALID(node)) {
			error = EIO;
			NG_FREE_ITEM(item);
			break;
		}
		/*
		 * If no receive method, just silently drop it.
		 * Give preference to the hook over-ride method
		 */
		if ((!(rcvdata = hook->hk_rcvdata))
		&& (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
			error = 0;
			NG_FREE_ITEM(item);
			break;
		}
		error = (*rcvdata)(hook, item);
		break;
	case NGQF_MESG:
		if (hook && NG_HOOK_NOT_VALID(hook)) {
			/*
			 * The hook has been zapped then we can't use it.
			 * Immediately drop its reference.
			 * The message may not need it.
			 */
			NG_HOOK_UNREF(hook);
			hook = NULL;
		}
		/*
		 * Similarly, if the node is a zombie there is
		 * nothing we can do with it, drop everything.
		 */
		if (NG_NODE_NOT_VALID(node)) {
			TRAP_ERROR();
			error = EINVAL;
			NG_FREE_ITEM(item);
			break;
		}
		/*
		 * Call the appropriate message handler for the object.
		 * It is up to the message handler to free the message.
		 * If it's a generic message, handle it generically,
		 * otherwise call the type's message handler (if it exists).
		 * XXX (race). Remember that a queued message may
		 * reference a node or hook that has just been
		 * invalidated. It will exist as the queue code
		 * is holding a reference, but..
		 */
		if ((NGI_MSG(item)->header.typecookie == NGM_GENERIC_COOKIE) &&
		    ((NGI_MSG(item)->header.flags & NGF_RESP) == 0)) {
			error = ng_generic_msg(node, item, hook);
			break;
		}
		if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg))) &&
		    (!(rcvmsg = node->nd_type->rcvmsg))) {
			TRAP_ERROR();
			error = 0;
			NG_FREE_ITEM(item);
			break;
		}
		error = (*rcvmsg)(node, item, hook);
		break;
	case NGQF_FN:
	case NGQF_FN2:
		/*
		 *  We have to implicitly trust the hook,
		 * as some of these are used for system purposes
		 * where the hook is invalid. In the case of
		 * the shutdown message we allow it to hit
		 * even if the node is invalid.
		 */
		if ((NG_NODE_NOT_VALID(node))
		&& (NGI_FN(item) != &ng_rmnode)) {
			TRAP_ERROR();
			error = EINVAL;
			NG_FREE_ITEM(item);
			break;
		}
		if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
			(*NGI_FN(item))(node, hook, NGI_ARG1(item),
			    NGI_ARG2(item));
			NG_FREE_ITEM(item);
		} else	/* it is NGQF_FN2 */
			error = (*NGI_FN2(item))(node, item, hook);
		break;
	}
	/*
	 * We held references on some of the resources
	 * that we took from the item. Now that we have
	 * finished doing everything, drop those references.
	 */
	if (hook)
		NG_HOOK_UNREF(hook);

	/* Release our node's token */
	ng_leave_readwrite(node);

	/* Free the item if we own the last reference to it. */
	ng_unref_item(item, error);

	NG_NODE_UNREF(node);

	return (error);
}

/***********************************************************************
 * Implement the 'generic' control messages
 ***********************************************************************/
static int
ng_generic_msg(node_p here, item_p item, hook_p lasthook)
{
	int error = 0;
	struct ng_mesg *msg;
	struct ng_mesg *resp = NULL;

	NGI_GET_MSG(item, msg);
	if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
		TRAP_ERROR();
		error = EINVAL;
		goto out;
	}
	switch (msg->header.cmd) {
	case NGM_SHUTDOWN:
		ng_rmnode(here, NULL, NULL, 0);
		break;
	case NGM_MKPEER:
	    {
		struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;

		if (msg->header.arglen != sizeof(*mkp)) {
			TRAP_ERROR();
			error = EINVAL;
			break;
		}
		mkp->type[sizeof(mkp->type) - 1] = '\0';
		mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
		mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
		error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
		break;
	    }
	case NGM_CONNECT:
	    {
		struct ngm_connect *const con =
			(struct ngm_connect *) msg->data;
		node_p node2;

		if (msg->header.arglen != sizeof(*con)) {
			TRAP_ERROR();
			error = EINVAL;
			break;
		}
		con->path[sizeof(con->path) - 1] = '\0';
		con->ourhook[sizeof(con->ourhook) - 1] = '\0';
		con->peerhook[sizeof(con->peerhook) - 1] = '\0';
		/* Don't forget we get a reference.. */
		error = ng_path2noderef(here, con->path, &node2, NULL);
		if (error)
			break;
		error = ng_con_nodes(item, here, con->ourhook,
		    node2, con->peerhook);
		NG_NODE_UNREF(node2);
		break;
	    }
	case NGM_NAME:
	    {
		struct ngm_name *const nam = (struct ngm_name *) msg->data;

		if (msg->header.arglen != sizeof(*nam)) {
			TRAP_ERROR();
			error = EINVAL;
			break;
		}
		nam->name[sizeof(nam->name) - 1] = '\0';
		error = ng_name_node(here, nam->name);
		break;
	    }
	case NGM_RMHOOK:
	    {
		struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
		hook_p hook;

		if (msg->header.arglen != sizeof(*rmh)) {
			TRAP_ERROR();
			error = EINVAL;
			break;
		}
		rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
		if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
			ng_destroy_hook(hook);
		break;
	    }
	case NGM_NODEINFO:
	    {
		struct nodeinfo *ni;

		NG_MKRESPONSE(resp, msg, sizeof(*ni), M_WAITOK | M_NULLOK);
		if (resp == NULL) {
			error = ENOMEM;
			break;
		}

		/* Fill in node info */
		ni = (struct nodeinfo *) resp->data;
		if (NG_NODE_HAS_NAME(here))
			strcpy(ni->name, NG_NODE_NAME(here));
		strcpy(ni->type, here->nd_type->name);
		ni->id = ng_node2ID(here);
		ni->hooks = here->nd_numhooks;
		break;
	    }
	case NGM_LISTHOOKS:
	    {
		const int nhooks = here->nd_numhooks;
		struct hooklist *hl;
		struct nodeinfo *ni;
		hook_p hook;

		/* Get response struct */
		NG_MKRESPONSE(resp, msg, sizeof(*hl)
		    + (nhooks * sizeof(struct linkinfo)), M_WAITOK | M_NULLOK);
		if (resp == NULL) {
			error = ENOMEM;
			break;
		}
		hl = (struct hooklist *) resp->data;
		ni = &hl->nodeinfo;

		/* Fill in node info */
		if (NG_NODE_HAS_NAME(here))
			strcpy(ni->name, NG_NODE_NAME(here));
		strcpy(ni->type, here->nd_type->name);
		ni->id = ng_node2ID(here);

		/* Cycle through the linked list of hooks */
		ni->hooks = 0;
		LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
			struct linkinfo *const link = &hl->link[ni->hooks];

			if (ni->hooks >= nhooks) {
				log(LOG_ERR, "%s: number of %s changed\n",
				    __func__, "hooks");
				break;
			}
			if (NG_HOOK_NOT_VALID(hook))
				continue;
			strcpy(link->ourhook, NG_HOOK_NAME(hook));
			strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
			if (NG_PEER_NODE_NAME(hook)[0] != '\0')
				strcpy(link->nodeinfo.name,
				    NG_PEER_NODE_NAME(hook));
			strcpy(link->nodeinfo.type,
			   NG_PEER_NODE(hook)->nd_type->name);
			link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
			link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
			ni->hooks++;
		}
		break;
	    }

	case NGM_LISTNODES:
	    {
		struct namelist *nl;
		node_p node;
		int i;

		IDHASH_RLOCK();
		/* Get response struct. */
		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
		    (ng_nodes * sizeof(struct nodeinfo)), M_NOWAIT | M_ZERO);
		if (resp == NULL) {
			IDHASH_RUNLOCK();
			error = ENOMEM;
			break;
		}
		nl = (struct namelist *) resp->data;

		/* Cycle through the lists of nodes. */
		nl->numnames = 0;
		for (i = 0; i <= ng_ID_hmask; i++) {
			LIST_FOREACH(node, &ng_ID_hash[i], nd_idnodes) {
				struct nodeinfo *const np =
				    &nl->nodeinfo[nl->numnames];

				if (NG_NODE_NOT_VALID(node))
					continue;
				if (NG_NODE_HAS_NAME(node))
					strcpy(np->name, NG_NODE_NAME(node));
				strcpy(np->type, node->nd_type->name);
				np->id = ng_node2ID(node);
				np->hooks = node->nd_numhooks;
				KASSERT(nl->numnames < ng_nodes,
				    ("%s: no space", __func__));
				nl->numnames++;
			}
		}
		IDHASH_RUNLOCK();
		break;
	    }
	case NGM_LISTNAMES:
	    {
		struct namelist *nl;
		node_p node;
		int i;

		NAMEHASH_RLOCK();
		/* Get response struct. */
		NG_MKRESPONSE(resp, msg, sizeof(*nl) +
		    (ng_named_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
		if (resp == NULL) {
			NAMEHASH_RUNLOCK();
			error = ENOMEM;
			break;
		}
		nl = (struct namelist *) resp->data;

		/* Cycle through the lists of nodes. */
		nl->numnames = 0;
		for (i = 0; i <= ng_name_hmask; i++) {
			LIST_FOREACH(node, &ng_name_hash[i], nd_nodes) {
				struct nodeinfo *const np =
				    &nl->nodeinfo[nl->numnames];

				if (NG_NODE_NOT_VALID(node))
					continue;
				strcpy(np->name, NG_NODE_NAME(node));
				strcpy(np->type, node->nd_type->name);
				np->id = ng_node2ID(node);
				np->hooks = node->nd_numhooks;
				KASSERT(nl->numnames < ng_named_nodes,
				    ("%s: no space", __func__));
				nl->numnames++;
			}
		}
		NAMEHASH_RUNLOCK();
		break;
	    }

	case NGM_LISTTYPES:
	    {
		struct typelist *tl;
		struct ng_type *type;
		int num = 0;

		TYPELIST_RLOCK();
		/* Count number of types */
		LIST_FOREACH(type, &ng_typelist, types)
			num++;

		/* Get response struct */
		NG_MKRESPONSE(resp, msg, sizeof(*tl)
		    + (num * sizeof(struct typeinfo)), M_WAITOK | M_NULLOK);
		if (resp == NULL) {
			TYPELIST_RUNLOCK();
			error = ENOMEM;
			break;
		}
		tl = (struct typelist *) resp->data;

		/* Cycle through the linked list of types */
		tl->numtypes = 0;
		LIST_FOREACH(type, &ng_typelist, types) {
			struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];

			strcpy(tp->type_name, type->name);
			tp->numnodes = type->refs - 1; /* don't count list */
			KASSERT(tl->numtypes < num, ("%s: no space", __func__));
			tl->numtypes++;
		}
		TYPELIST_RUNLOCK();
		break;
	    }

	case NGM_BINARY2ASCII:
	    {
		int bufSize = 20 * 1024;	/* XXX hard coded constant */
		const struct ng_parse_type *argstype;
		const struct ng_cmdlist *c;
		struct ng_mesg *binary, *ascii;

		/* Data area must contain a valid netgraph message */
		binary = (struct ng_mesg *)msg->data;
		if (msg->header.arglen < sizeof(struct ng_mesg) ||
		    (msg->header.arglen - sizeof(struct ng_mesg) <
		    binary->header.arglen)) {
			TRAP_ERROR();
			error = EINVAL;
			break;
		}

		/* Get a response message with lots of room */
		NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_WAITOK | M_NULLOK);
		if (resp == NULL) {
			error = ENOMEM;
			break;
		}
		ascii = (struct ng_mesg *)resp->data;

		/* Copy binary message header to response message payload */
		bcopy(binary, ascii, sizeof(*binary));

		/* Find command by matching typecookie and command number */
		for (c = here->nd_type->cmdlist;
		    c != NULL && c->name != NULL; c++) {
			if (binary->header.typecookie == c->cookie
			    && binary->header.cmd == c->cmd)
				break;
		}
		if (c == NULL || c->name == NULL) {
			for (c = ng_generic_cmds; c->name != NULL; c++) {
				if (binary->header.typecookie == c->cookie
				    && binary->header.cmd == c->cmd)
					break;
			}
			if (c->name == NULL) {
				NG_FREE_MSG(resp);
				error = ENOSYS;
				break;
			}
		}

		/* Convert command name to ASCII */
		ksnprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
		    "%s", c->name);

		/* Convert command arguments to ASCII */
		argstype = (binary->header.flags & NGF_RESP) ?
		    c->respType : c->mesgType;
		if (argstype == NULL) {
			*ascii->data = '\0';
		} else {
			if ((error = ng_unparse(argstype,
			    (u_char *)binary->data,
			    ascii->data, bufSize)) != 0) {
				NG_FREE_MSG(resp);
				break;
			}
		}

		/* Return the result as struct ng_mesg plus ASCII string */
		bufSize = strlen(ascii->data) + 1;
		ascii->header.arglen = bufSize;
		resp->header.arglen = sizeof(*ascii) + bufSize;
		break;
	    }

	case NGM_ASCII2BINARY:
	    {
		int bufSize = 2000;	/* XXX hard coded constant */
		const struct ng_cmdlist *c;
		const struct ng_parse_type *argstype;
		struct ng_mesg *ascii, *binary;
		int off = 0;

		/* Data area must contain at least a struct ng_mesg + '\0' */
		ascii = (struct ng_mesg *)msg->data;
		if ((msg->header.arglen < sizeof(*ascii) + 1) ||
		    (ascii->header.arglen < 1) ||
		    (msg->header.arglen < sizeof(*ascii) +
		    ascii->header.arglen)) {
			TRAP_ERROR();
			error = EINVAL;
			break;
		}
		ascii->data[ascii->header.arglen - 1] = '\0';

		/* Get a response message with lots of room */
		NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_WAITOK | M_NULLOK);
		if (resp == NULL) {
			error = ENOMEM;
			break;
		}
		binary = (struct ng_mesg *)resp->data;

		/* Copy ASCII message header to response message payload */
		bcopy(ascii, binary, sizeof(*ascii));

		/* Find command by matching ASCII command string */
		for (c = here->nd_type->cmdlist;
		    c != NULL && c->name != NULL; c++) {
			if (strcmp(ascii->header.cmdstr, c->name) == 0)
				break;
		}
		if (c == NULL || c->name == NULL) {
			for (c = ng_generic_cmds; c->name != NULL; c++) {
				if (strcmp(ascii->header.cmdstr, c->name) == 0)
					break;
			}
			if (c->name == NULL) {
				NG_FREE_MSG(resp);
				error = ENOSYS;
				break;
			}
		}

		/* Convert command name to binary */
		binary->header.cmd = c->cmd;
		binary->header.typecookie = c->cookie;

		/* Convert command arguments to binary */
		argstype = (binary->header.flags & NGF_RESP) ?
		    c->respType : c->mesgType;
		if (argstype == NULL) {
			bufSize = 0;
		} else {
			if ((error = ng_parse(argstype, ascii->data,
			    &off, (u_char *)binary->data, &bufSize)) != 0) {
				NG_FREE_MSG(resp);
				break;
			}
		}

		/* Return the result */
		binary->header.arglen = bufSize;
		resp->header.arglen = sizeof(*binary) + bufSize;
		break;
	    }

	case NGM_TEXT_CONFIG:
	case NGM_TEXT_STATUS:
		/*
		 * This one is tricky as it passes the command down to the
		 * actual node, even though it is a generic type command.
		 * This means we must assume that the item/msg is already freed
		 * when control passes back to us.
		 */
		if (here->nd_type->rcvmsg != NULL) {
			NGI_MSG(item) = msg; /* put it back as we found it */
			return((*here->nd_type->rcvmsg)(here, item, lasthook));
		}
		/* Fall through if rcvmsg not supported */
	default:
		TRAP_ERROR();
		error = EINVAL;
	}
	/*
	 * Sometimes a generic message may be statically allocated
	 * to avoid problems with allocating when in tight memeory situations.
	 * Don't free it if it is so.
	 * I break them appart here, because erros may cause a free if the item
	 * in which case we'd be doing it twice.
	 * they are kept together above, to simplify freeing.
	 */
out:
	NG_RESPOND_MSG(error, here, item, resp);
	if (msg)
		NG_FREE_MSG(msg);
	return (error);
}

/************************************************************************
			Queue element get/free routines
************************************************************************/

static struct objcache	*ng_oc;
static struct objcache	*ng_apply_oc;
static int		 maxalloc = 4096; /* limit the damage of a leak */

TUNABLE_INT("net.graph.maxalloc", &maxalloc);
SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RD, &maxalloc,
    0, "Maximum number of queue items to allocate");

#ifdef	NETGRAPH_DEBUG
static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
static int			allocated;	/* number of items malloc'd */
#endif

/*
 * Get a queue entry.
 * This is usually called when a packet first enters netgraph.
 * By definition, this is usually from an interrupt, or from a user.
 * Users are not so important, but try be quick for the times that it's
 * an interrupt.
 */
static __inline item_p
ng_alloc_item(int type, int flags)
{
	item_p item;

	KASSERT(((type & ~NGQF_TYPE) == 0),
	    ("%s: incorrect item type: %d", __func__, type));

	item = objcache_get(ng_oc,
	    (flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT );

	if (item) {
		item->el_flags = type;
#ifdef	NETGRAPH_DEBUG
		mtx_lock(&ngq_mtx);
		TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
		allocated++;
		mtx_unlock(&ngq_mtx);
#endif
	}

	return (item);
}

/*
 * Release a queue entry
 */
void
ng_free_item(item_p item)
{
	/*
	 * If the item still has an apply callback registered, it is
	 * being freed too early.
	 */
	KASSERT(item->apply == NULL, ("freeing item with registered callback"));

	/*
	 * Make sure the reference count has reached zero.
	 */
	KASSERT(item->refs == 0, ("freeing item with non-zero refcount"));

	/*
	 * The item may hold resources on it's own. We need to free
	 * these before we can free the item. What they are depends upon
	 * what kind of item it is. it is important that nodes zero
	 * out pointers to resources that they remove from the item
	 * or we release them again here.
	 */
	switch (item->el_flags & NGQF_TYPE) {
	case NGQF_DATA:
		/* If we have an mbuf still attached.. */
		NG_FREE_M(_NGI_M(item));
		break;
	case NGQF_MESG:
		_NGI_RETADDR(item) = 0;
		NG_FREE_MSG(_NGI_MSG(item));
		break;
	case NGQF_FN:
	case NGQF_FN2:
		/* nothing to free really, */
		_NGI_FN(item) = NULL;
		_NGI_ARG1(item) = NULL;
		_NGI_ARG2(item) = 0;
		break;
	}
	/* If we still have a node or hook referenced... */
	_NGI_CLR_NODE(item);
	_NGI_CLR_HOOK(item);

#ifdef	NETGRAPH_DEBUG
	mtx_lock(&ngq_mtx);
	TAILQ_REMOVE(&ng_itemlist, item, all);
	allocated--;
	mtx_unlock(&ngq_mtx);
#endif
	/* Object must be initialized before returning to objcache */
	bzero(item, sizeof(struct ng_item));
	objcache_put(ng_oc, item);
}

/*
 * Change type of the queue entry.
 */
static __inline item_p
ng_realloc_item(item_p item, int type, int flags)
{

	KASSERT((item != NULL), ("%s: can't reallocate NULL", __func__));
	KASSERT(((type & ~NGQF_TYPE) == 0),
	    ("%s: incorrect item type: %d", __func__, type));

	item->el_flags = (item->el_flags & ~NGQF_TYPE) | type;

	return (item);
}

__inline apply_p
ng_alloc_apply(void)
{
	return (objcache_get(ng_apply_oc, M_WAITOK));
}

__inline void
ng_free_apply(apply_p apply)
{
	objcache_put(ng_apply_oc, apply);
}

/************************************************************************
			Module routines
************************************************************************/

/*
 * Handle the loading/unloading of a netgraph node type module
 */
int
ng_mod_event(module_t mod, int event, void *data)
{
	struct ng_type *const type = data;
	int error = 0;

	switch (event) {
	case MOD_LOAD:

		/* Register new netgraph node type */
		if ((error = ng_newtype(type)) != 0) {
			break;
		}

		/* Call type specific code */
		if (type->mod_event != NULL)
			if ((error = (*type->mod_event)(mod, event, data))) {
				TYPELIST_WLOCK();
				type->refs--;	/* undo it */
				LIST_REMOVE(type, types);
				TYPELIST_WUNLOCK();
			}
		break;

	case MOD_UNLOAD:
		if (type->refs > 1) {		/* make sure no nodes exist! */
			error = EBUSY;
		} else {
			if (type->refs == 0) {
				/* failed load, nothing to undo */
				break;
			}
			if (type->mod_event != NULL) {	/* check with type */
				error = (*type->mod_event)(mod, event, data);
				if (error != 0) {	/* type refuses.. */
					break;
				}
			}
			TYPELIST_WLOCK();
			LIST_REMOVE(type, types);
			TYPELIST_WUNLOCK();
		}
		break;

	default:
		if (type->mod_event != NULL)
			error = (*type->mod_event)(mod, event, data);
		else
			error = EOPNOTSUPP;		/* XXX ? */
		break;
	}
	return (error);
}

/*
 * Handle loading and unloading for this code.
 */
static int
ngb_mod_event(module_t mod, int event, void *data)
{
	int i, error = 0;

	switch (event) {
	case MOD_LOAD:
		/* Initialize everything. */
		lwkt_token_init(&ng_typelist_token, "ng typelist");
		lwkt_token_init(&ng_idhash_token, "ng idhash");
		lwkt_token_init(&ng_namehash_token, "ng namehash");
		lwkt_token_init(&ng_topo_token, "ng topology");
#ifdef	NETGRAPH_DEBUG
		mtx_init(&ng_nodelist_mtx, "ng nodelist");
		mtx_init(&ngq_mtx, "ng queue");
#endif
		ng_oc = objcache_create_mbacked(M_NETGRAPH,
			    sizeof(struct ng_item), maxalloc, 0, bzero_ctor,
			    NULL, NULL);
		ng_apply_oc = objcache_create_mbacked(M_NETGRAPH_APPLY,
			    sizeof(struct ng_apply_info), 0, 0, bzero_ctor,
			    NULL, NULL);

		/* We start with small hashes, but they can grow. */
		ng_ID_hash = hashinit(16, M_NETGRAPH_NODE, &ng_ID_hmask);
		ng_name_hash = hashinit(16, M_NETGRAPH_NODE, &ng_name_hmask);

		lwkt_initport_panic(&ng_panic_reply_port);
		for (i = 0; i < ncpus; ++i) {
			thread_t td;

			lwkt_create(ngthread, NULL, &td,
			   NULL, 0, i, "netgraph %d", i);
			ng_msgport[i] = &td->td_msgport;
		}
		break;
	case MOD_UNLOAD:
#if 0
		hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
		hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_ID_hmask);

		/* Destroy the lwkt threads too */

		objcache_destroy(ng_apply_oc);
		objcache_destroy(ng_oc);
#endif
		/* You can't unload it because an interface may be using it. */
		error = EBUSY;
		break;
	default:
		error = EOPNOTSUPP;
		break;
	}
	return (error);
}

static moduledata_t netgraph_mod = {
	"netgraph",
	ngb_mod_event,
	(NULL)
};
DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_MIDDLE);
SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW, 0, "netgraph Family");
SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, 0, NG_ABI_VERSION,"");
SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, 0, NG_VERSION, "");

#ifdef	NETGRAPH_DEBUG
void
dumphook (hook_p hook, char *file, int line)
{
	kprintf("hook: name %s, %d refs, Last touched:\n",
		_NG_HOOK_NAME(hook), hook->hk_refs);
	kprintf("	Last active @ %s, line %d\n",
		hook->lastfile, hook->lastline);
	if (line) {
		kprintf(" problem discovered at file %s, line %d\n", file, line);
	}
}

void
dumpnode(node_p node, char *file, int line)
{
	kprintf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
		_NG_NODE_ID(node), node->nd_type->name,
		node->nd_numhooks, node->nd_flags,
		node->nd_refs, node->nd_name);
	kprintf("	Last active @ %s, line %d\n",
		node->lastfile, node->lastline);
	if (line) {
		kprintf(" problem discovered at file %s, line %d\n", file, line);
	}
}

void
dumpitem(item_p item, char *file, int line)
{
	kprintf(" ACTIVE item, last used at %s, line %d",
		item->lastfile, item->lastline);
	switch(item->el_flags & NGQF_TYPE) {
	case NGQF_DATA:
		kprintf(" - [data]\n");
		break;
	case NGQF_MESG:
		kprintf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
		break;
	case NGQF_FN:
		kprintf(" - fn@%p (%p, %p, %p, %d (%x))\n",
			_NGI_FN(item),
			_NGI_NODE(item),
			_NGI_HOOK(item),
			item->body.fn.fn_arg1,
			item->body.fn.fn_arg2,
			item->body.fn.fn_arg2);
		break;
	case NGQF_FN2:
		kprintf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
			_NGI_FN2(item),
			_NGI_NODE(item),
			_NGI_HOOK(item),
			item->body.fn.fn_arg1,
			item->body.fn.fn_arg2,
			item->body.fn.fn_arg2);
		break;
	}
	if (line) {
		kprintf(" problem discovered at file %s, line %d\n", file, line);
		if (_NGI_NODE(item)) {
			kprintf("node %p ([%x])\n",
				_NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
		}
	}
}

static void
ng_dumpitems(void)
{
	item_p item;
	int i = 1;
	TAILQ_FOREACH(item, &ng_itemlist, all) {
		kprintf("[%d] ", i++);
		dumpitem(item, NULL, 0);
	}
}

static void
ng_dumpnodes(void)
{
	node_p node;
	int i = 1;
	mtx_lock(&ng_nodelist_mtx);
	SLIST_FOREACH(node, &ng_allnodes, nd_all) {
		kprintf("[%d] ", i++);
		dumpnode(node, NULL, 0);
	}
	mtx_unlock(&ng_nodelist_mtx);
}

static void
ng_dumphooks(void)
{
	hook_p hook;
	int i = 1;
	mtx_lock(&ng_nodelist_mtx);
	SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
		kprintf("[%d] ", i++);
		dumphook(hook, NULL, 0);
	}
	mtx_unlock(&ng_nodelist_mtx);
}

static int
sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
{
	int error;
	int val;

	val = allocated;
	error = sysctl_handle_int(oidp, &val, 0, req);
	if (error != 0 || req->newptr == NULL)
		return (error);
	if (val == 42) {
		ng_dumpitems();
		ng_dumpnodes();
		ng_dumphooks();
	}
	return (0);
}

SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items, CTLTYPE_INT | CTLFLAG_RW,
    0, sizeof(int), sysctl_debug_ng_dump_items, "I", "Number of allocated items");
#endif	/* NETGRAPH_DEBUG */


/***********************************************************************
* Externally useable functions to set up a queue item ready for sending
***********************************************************************/

#ifdef	NETGRAPH_DEBUG
#define	ITEM_DEBUG_CHECKS						\
	do {								\
		if (NGI_NODE(item) ) {					\
			kprintf("item already has node");		\
			kdb_enter(KDB_WHY_NETGRAPH, "has node");	\
			NGI_CLR_NODE(item);				\
		}							\
		if (NGI_HOOK(item) ) {					\
			kprintf("item already has hook");		\
			kdb_enter(KDB_WHY_NETGRAPH, "has hook");	\
			NGI_CLR_HOOK(item);				\
		}							\
	} while (0)
#else
#define ITEM_DEBUG_CHECKS
#endif

/*
 * Put mbuf into the item.
 * Hook and node references will be removed when the item is dequeued.
 * (or equivalent)
 * (XXX) Unsafe because no reference held by peer on remote node.
 * remote node might go away in this timescale.
 * We know the hooks can't go away because that would require getting
 * a writer item on both nodes and we must have at least a  reader
 * here to be able to do this.
 * Note that the hook loaded is the REMOTE hook.
 *
 * This is possibly in the critical path for new data.
 */
item_p
ng_package_data(struct mbuf *m, int flags)
{
	item_p item;

	if ((item = ng_alloc_item(NGQF_DATA, flags)) == NULL) {
		NG_FREE_M(m);
		return (NULL);
	}
	ITEM_DEBUG_CHECKS;
	item->el_flags |= NGQF_READER;
	NGI_M(item) = m;
	return (item);
}

/*
 * Allocate a queue item and put items into it..
 * Evaluate the address as this will be needed to queue it and
 * to work out what some of the fields should be.
 * Hook and node references will be removed when the item is dequeued.
 * (or equivalent)
 */
item_p
ng_package_msg(struct ng_mesg *msg, int flags)
{
	item_p item;

	if ((item = ng_alloc_item(NGQF_MESG, flags)) == NULL) {
		NG_FREE_MSG(msg);
		return (NULL);
	}
	ITEM_DEBUG_CHECKS;
	/* Messages items count as writers unless explicitly exempted. */
	if (msg->header.cmd & NGM_READONLY)
		item->el_flags |= NGQF_READER;
	else
		item->el_flags |= NGQF_WRITER;
	/*
	 * Set the current lasthook into the queue item
	 */
	NGI_MSG(item) = msg;
	NGI_RETADDR(item) = 0;
	return (item);
}



#define SET_RETADDR(item, here, retaddr)				\
	do {	/* Data or fn items don't have retaddrs */		\
		if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {	\
			if (retaddr) {					\
				NGI_RETADDR(item) = retaddr;		\
			} else {					\
				/*					\
				 * The old return address should be ok.	\
				 * If there isn't one, use the address	\
				 * here.				\
				 */					\
				if (NGI_RETADDR(item) == 0) {		\
					NGI_RETADDR(item)		\
						= ng_node2ID(here);	\
				}					\
			}						\
		}							\
	} while (0)

int
ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
{
	hook_p peer;
	node_p peernode;
	ITEM_DEBUG_CHECKS;
	/*
	 * Quick sanity check..
	 * Since a hook holds a reference on it's node, once we know
	 * that the peer is still connected (even if invalid,) we know
	 * that the peer node is present, though maybe invalid.
	 */
	if ((hook == NULL) ||
	    NG_HOOK_NOT_VALID(hook) ||
	    NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
	    NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
		NG_FREE_ITEM(item);
		TRAP_ERROR();
		return (ENETDOWN);
	}

	/*
	 * Transfer our interest to the other (peer) end.
	 */
	NG_HOOK_REF(peer);
	NG_NODE_REF(peernode);
	NGI_SET_HOOK(item, peer);
	NGI_SET_NODE(item, peernode);
	SET_RETADDR(item, here, retaddr);
	return (0);
}

int
ng_address_path(node_p here, item_p item, char *address, ng_ID_t retaddr)
{
	node_p	dest = NULL;
	hook_p	hook = NULL;
	int	error;

	ITEM_DEBUG_CHECKS;
	/*
	 * Note that ng_path2noderef increments the reference count
	 * on the node for us if it finds one. So we don't have to.
	 */
	error = ng_path2noderef(here, address, &dest, &hook);
	if (error) {
		NG_FREE_ITEM(item);
		return (error);
	}
	NGI_SET_NODE(item, dest);
	if ( hook) {
		NG_HOOK_REF(hook);	/* don't let it go while on the queue */
		NGI_SET_HOOK(item, hook);
	}
	SET_RETADDR(item, here, retaddr);
	return (0);
}

int
ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
{
	node_p dest;

	ITEM_DEBUG_CHECKS;
	/*
	 * Find the target node.
	 */
	dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
	if (dest == NULL) {
		NG_FREE_ITEM(item);
		TRAP_ERROR();
		return(EINVAL);
	}
	/* Fill out the contents */
	NGI_SET_NODE(item, dest);
	NGI_CLR_HOOK(item);
	SET_RETADDR(item, here, retaddr);
	return (0);
}

/*
 * special case to send a message to self (e.g. destroy node)
 * Possibly indicate an arrival hook too.
 * Useful for removing that hook :-)
 */
item_p
ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
{
	item_p item;

	/*
	 * Find the target node.
	 * If there is a HOOK argument, then use that in preference
	 * to the address.
	 */
	if ((item = ng_alloc_item(NGQF_MESG, NG_NOFLAGS)) == NULL) {
		NG_FREE_MSG(msg);
		return (NULL);
	}

	/* Fill out the contents */
	item->el_flags |= NGQF_WRITER;
	NG_NODE_REF(here);
	NGI_SET_NODE(item, here);
	if (hook) {
		NG_HOOK_REF(hook);
		NGI_SET_HOOK(item, hook);
	}
	NGI_MSG(item) = msg;
	NGI_RETADDR(item) = ng_node2ID(here);
	return (item);
}

/*
 * Send ng_item_fn function call to the specified node.
 */

int
ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
{
	return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
}

int
ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
	int flags)
{
	item_p item;

	if ((item = ng_alloc_item(NGQF_FN, flags)) == NULL) {
		return (ENOMEM);
	}
	item->el_flags |= NGQF_WRITER;
	NG_NODE_REF(node); /* and one for the item */
	NGI_SET_NODE(item, node);
	if (hook) {
		NG_HOOK_REF(hook);
		NGI_SET_HOOK(item, hook);
	}
	NGI_FN(item) = fn;
	NGI_ARG1(item) = arg1;
	NGI_ARG2(item) = arg2;
	return(ng_snd_item(item, flags));
}

/*
 * Send ng_item_fn2 function call to the specified node.
 *
 * If NG_REUSE_ITEM flag is set, no new item will be allocated,
 * pitem will be used instead.
 */
int
ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
	int arg2, int flags)
{
	item_p item;

	KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
	    ("%s: NG_REUSE_ITEM but no pitem", __func__));

	/*
	 * Allocate a new item if no supplied or
	 * if we can't use supplied one.
	 */
	if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
		if ((item = ng_alloc_item(NGQF_FN2, flags)) == NULL)
			return (ENOMEM);
	} else {
		if ((item = ng_realloc_item(pitem, NGQF_FN2, flags)) == NULL)
			return (ENOMEM);
	}

	item->el_flags = (item->el_flags & ~NGQF_RW) | NGQF_WRITER;
	NG_NODE_REF(node); /* and one for the item */
	NGI_SET_NODE(item, node);
	if (hook) {
		NG_HOOK_REF(hook);
		NGI_SET_HOOK(item, hook);
	}
	NGI_FN2(item) = fn;
	NGI_ARG1(item) = arg1;
	NGI_ARG2(item) = arg2;
	return(ng_snd_item(item, flags));
}

/*
 * Official timeout routines for Netgraph nodes.
 */
static void
ng_callout_trampoline(void *arg)
{
	item_p item = arg;

	ng_snd_item(item, 0);
}


int
ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
    ng_item_fn *fn, void * arg1, int arg2)
{
	item_p item, oitem;

	if ((item = ng_alloc_item(NGQF_FN, NG_NOFLAGS)) == NULL)
		return (ENOMEM);

	item->el_flags |= NGQF_WRITER;
	NG_NODE_REF(node);		/* and one for the item */
	NGI_SET_NODE(item, node);
	if (hook) {
		NG_HOOK_REF(hook);
		NGI_SET_HOOK(item, hook);
	}
	NGI_FN(item) = fn;
	NGI_ARG1(item) = arg1;
	NGI_ARG2(item) = arg2;
	oitem = callout_arg(c);
	callout_reset(c, ticks, &ng_callout_trampoline, item);
	return (0);
}

/* A special modified version of untimeout() */
int
ng_uncallout(struct callout *c, node_p node)
{
	item_p item;
	int rval;

	KASSERT(c != NULL, ("ng_uncallout: NULL callout"));
	KASSERT(node != NULL, ("ng_uncallout: NULL node"));

	rval = callout_stop(c);
	item = callout_arg(c);
	/* Do an extra check */
	if ((rval > 0) && (callout_func(c) == &ng_callout_trampoline) &&
	    (NGI_NODE(item) == node)) {
		/*
		 * We successfully removed it from the queue before it ran
		 * So now we need to unreference everything that was
		 * given extra references. (NG_FREE_ITEM does this).
		 */
		NG_FREE_ITEM(item);
	}
	callout_set_arg(c, NULL);

	return (rval);
}

/*
 * Set the address, if none given, give the node here.
 */
void
ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
{
	if (retaddr) {
		NGI_RETADDR(item) = retaddr;
	} else {
		/*
		 * The old return address should be ok.
		 * If there isn't one, use the address here.
		 */
		NGI_RETADDR(item) = ng_node2ID(here);
	}
}

static boolean_t
bzero_ctor(void *obj, void *private, int ocflags)
{
	struct ng_item *i = obj;

	bzero(i, sizeof(struct ng_item));
	return(TRUE);
}

#define TESTING
#ifdef TESTING
/* just test all the macros */
void
ng_macro_test(item_p item);
void
ng_macro_test(item_p item)
{
	node_p node = NULL;
	hook_p hook = NULL;
	struct mbuf *m;
	struct ng_mesg *msg;
	ng_ID_t retaddr;
	int	error;

	NGI_GET_M(item, m);
	NGI_GET_MSG(item, msg);
	retaddr = NGI_RETADDR(item);
	NG_SEND_DATA(error, hook, m, NULL);
	NG_SEND_DATA_ONLY(error, hook, m);
	NG_FWD_NEW_DATA(error, item, hook, m);
	NG_FWD_ITEM_HOOK(error, item, hook);
	NG_SEND_MSG_HOOK(error, node, msg, hook, retaddr);
	NG_SEND_MSG_ID(error, node, msg, retaddr, retaddr);
	NG_SEND_MSG_PATH(error, node, msg, ".:", retaddr);
	NG_FWD_MSG_HOOK(error, node, item, hook, retaddr);
}
#endif /* TESTING */