ng_hole.c

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/*
 * ng_hole.c
 */
 
/*-
 * 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.
 *
 * Author: Julian Elisher <julian@freebsd.org>
 *
 * $FreeBSD$
 * $Whistle: ng_hole.c,v 1.10 1999/11/01 09:24:51 julian Exp $
 */
 
/*
 * This node is a 'black hole' that simply discards everything it receives
 */
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_hole.h>
 
/* Per hook private info. */
struct ng_hole_hookinfo {
        struct ng_hole_hookstat stats;
};
typedef struct ng_hole_hookinfo *hinfo_p;
 
/* Parse type for struct ng_hole_hookstat. */
static const struct ng_parse_struct_field ng_hole_hookstat_type_fields[] =
        NG_HOLE_HOOKSTAT_TYPE_INFO;
static const struct ng_parse_type ng_hole_hookstat_type = {
        &ng_parse_struct_type,
        &ng_hole_hookstat_type_fields
};
 
/* List of commands and how to convert arguments to/from ASCII. */
static const struct ng_cmdlist ng_hole_cmdlist[] = {
        {
          NGM_HOLE_COOKIE,
          NGM_HOLE_GET_STATS,
          "getstats",
          &ng_parse_hookbuf_type,
          &ng_hole_hookstat_type
        },
        {
          NGM_HOLE_COOKIE,
          NGM_HOLE_CLR_STATS,
          "clrstats",
          &ng_parse_hookbuf_type,
          NULL
        },
        {
          NGM_HOLE_COOKIE,
          NGM_HOLE_GETCLR_STATS,
          "getclrstats",
          &ng_parse_hookbuf_type,
          &ng_hole_hookstat_type
        },
        { 0 }
};
 
/* Netgraph methods */
static ng_constructor_t ngh_cons;
static ng_rcvmsg_t      ngh_rcvmsg;
static ng_newhook_t     ngh_newhook;
static ng_rcvdata_t     ngh_rcvdata;
static ng_disconnect_t  ngh_disconnect;
 
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_HOLE_NODE_TYPE,
        .constructor =  ngh_cons,
        .rcvmsg =       ngh_rcvmsg,
        .newhook =      ngh_newhook,
        .rcvdata =      ngh_rcvdata,
        .disconnect =   ngh_disconnect,
        .cmdlist =      ng_hole_cmdlist,
};
NETGRAPH_INIT(hole, &typestruct);
 
/* 
 * Be obliging. but no work to do.
 */
static int
ngh_cons(node_p node)
{
        return(0);
}
 
/*
 * Add a hook.
 */
static int
ngh_newhook(node_p node, hook_p hook, const char *name)
{
        hinfo_p hip;
 
        /* Create hook private structure. */
        hip = malloc(sizeof(*hip), M_NETGRAPH, M_NOWAIT | M_ZERO);
        if (hip == NULL)
                return (ENOMEM);
        NG_HOOK_SET_PRIVATE(hook, hip);
        return (0);
}
 
/*
 * Receive a control message.
 */
static int
ngh_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        struct ng_mesg *msg;
        struct ng_mesg *resp = NULL;
        int error = 0;
        struct ng_hole_hookstat *stats;
        hook_p hook;
 
        NGI_GET_MSG(item, msg);
        switch (msg->header.typecookie) {
        case NGM_HOLE_COOKIE:
                switch (msg->header.cmd) {
                case NGM_HOLE_GET_STATS:
                case NGM_HOLE_CLR_STATS:
                case NGM_HOLE_GETCLR_STATS:
                        /* Sanity check. */
                        if (msg->header.arglen != NG_HOOKSIZ) {
                                error = EINVAL;
                                break;
                        }
                        /* Find hook. */
                        hook = ng_findhook(node, (char *)msg->data);
                        if (hook == NULL) {
                                error = ENOENT;
                                break;
                        }
                        stats = &((hinfo_p)NG_HOOK_PRIVATE(hook))->stats;
                        /* Build response (if desired). */
                        if (msg->header.cmd != NGM_HOLE_CLR_STATS) {
                                NG_MKRESPONSE(resp, msg, sizeof(*stats),
                                    M_NOWAIT);
                                if (resp == NULL) {
                                        error = ENOMEM;
                                        break;
                                }
                                bcopy(stats, resp->data, sizeof(*stats));
                        }
                        /* Clear stats (if desired). */
                        if (msg->header.cmd != NGM_HOLE_GET_STATS)
                                bzero(stats, sizeof(*stats));
                        break;
                default:                /* Unknown command. */
                        error = EINVAL;
                        break;
                }
                break;
        default:                        /* Unknown type cookie. */
                error = EINVAL;
                break;
        }
        NG_RESPOND_MSG(error, node, item, resp);
        NG_FREE_MSG(msg);
        return (error);
}
 
/*
 * Receive data
 */
static int
ngh_rcvdata(hook_p hook, item_p item)
{
        const hinfo_p hip = NG_HOOK_PRIVATE(hook);
 
        hip->stats.frames++;
        hip->stats.octets += NGI_M(item)->m_pkthdr.len;
        NG_FREE_ITEM(item);
        return 0;
}
 
/*
 * Hook disconnection
 */
static int
ngh_disconnect(hook_p hook)
{
 
        free(NG_HOOK_PRIVATE(hook), M_NETGRAPH);
        NG_HOOK_SET_PRIVATE(hook, NULL);
        if (NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
                ng_rmnode_self(NG_HOOK_NODE(hook));
        return (0);
}