ng_sample.c

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/*
 * ng_sample.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 Elischer <julian@freebsd.org>
 *
 * $FreeBSD$
 * $Whistle: ng_sample.c,v 1.13 1999/11/01 09:24:52 julian Exp $
 */
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/ctype.h>
#include <sys/errno.h>
#include <sys/syslog.h>
 
#include <netgraph/ng_message.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_sample.h>
#include <netgraph/netgraph.h>
 
/* If you do complicated mallocs you may want to do this */
/* and use it for your mallocs */
#ifdef NG_SEPARATE_MALLOC
static MALLOC_DEFINE(M_NETGRAPH_XXX, "netgraph_xxx", "netgraph xxx node");
#else
#define M_NETGRAPH_XXX M_NETGRAPH
#endif
 
/*
 * This section contains the netgraph method declarations for the
 * sample node. These methods define the netgraph 'type'.
 */
 
static ng_constructor_t ng_xxx_constructor;
static ng_rcvmsg_t      ng_xxx_rcvmsg;
static ng_shutdown_t    ng_xxx_shutdown;
static ng_newhook_t     ng_xxx_newhook;
static ng_connect_t     ng_xxx_connect;
static ng_rcvdata_t     ng_xxx_rcvdata;
static ng_disconnect_t  ng_xxx_disconnect;
 
/* Parse type for struct ngxxxstat */
static const struct ng_parse_struct_field ng_xxx_stat_type_fields[]
        = NG_XXX_STATS_TYPE_INFO;
static const struct ng_parse_type ng_xxx_stat_type = {
        &ng_parse_struct_type,
        &ng_xxx_stat_type_fields
};
 
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_xxx_cmdlist[] = {
        {
          NGM_XXX_COOKIE,
          NGM_XXX_GET_STATUS,
          "getstatus",
          NULL,
          &ng_xxx_stat_type,
        },
        {
          NGM_XXX_COOKIE,
          NGM_XXX_SET_FLAG,
          "setflag",
          &ng_parse_int32_type,
          NULL
        },
        { 0 }
};
 
/* Netgraph node type descriptor */
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_XXX_NODE_TYPE,
        .constructor =  ng_xxx_constructor,
        .rcvmsg =       ng_xxx_rcvmsg,
        .shutdown =     ng_xxx_shutdown,
        .newhook =      ng_xxx_newhook,
/*      .findhook =     ng_xxx_findhook,        */
        .connect =      ng_xxx_connect,
        .rcvdata =      ng_xxx_rcvdata,
        .disconnect =   ng_xxx_disconnect,
        .cmdlist =      ng_xxx_cmdlist,
};
NETGRAPH_INIT(xxx, &typestruct);
 
/* Information we store for each hook on each node */
struct XXX_hookinfo {
        int     dlci;           /* The DLCI it represents, -1 == downstream */
        int     channel;        /* The channel representing this DLCI */
        hook_p  hook;
};
 
/* Information we store for each node */
struct XXX {
        struct XXX_hookinfo channel[XXX_NUM_DLCIS];
        struct XXX_hookinfo downstream_hook;
        node_p          node;           /* back pointer to node */
        hook_p          debughook;
        u_int           packets_in;     /* packets in from downstream */
        u_int           packets_out;    /* packets out towards downstream */
        u_int32_t       flags;
};
typedef struct XXX *xxx_p;
 
/*
 * Allocate the private data structure. The generic node has already
 * been created. Link them together. We arrive with a reference to the node
 * i.e. the reference count is incremented for us already.
 *
 * If this were a device node than this work would be done in the attach()
 * routine and the constructor would return EINVAL as you should not be able
 * to creatednodes that depend on hardware (unless you can add the hardware :)
 */
static int
ng_xxx_constructor(node_p node)
{
        xxx_p privdata;
        int i;
 
        /* Initialize private descriptor */
        privdata = malloc(sizeof(*privdata), M_NETGRAPH, M_WAITOK | M_ZERO);
        for (i = 0; i < XXX_NUM_DLCIS; i++) {
                privdata->channel[i].dlci = -2;
                privdata->channel[i].channel = i;
        }
 
        /* Link structs together; this counts as our one reference to *nodep */
        NG_NODE_SET_PRIVATE(node, privdata);
        privdata->node = node;
        return (0);
}
 
/*
 * Give our ok for a hook to be added...
 * If we are not running this might kick a device into life.
 * Possibly decode information out of the hook name.
 * Add the hook's private info to the hook structure.
 * (if we had some). In this example, we assume that there is a
 * an array of structs, called 'channel' in the private info,
 * one for each active channel. The private
 * pointer of each hook points to the appropriate XXX_hookinfo struct
 * so that the source of an input packet is easily identified.
 * (a dlci is a frame relay channel)
 */
static int
ng_xxx_newhook(node_p node, hook_p hook, const char *name)
{
        const xxx_p xxxp = NG_NODE_PRIVATE(node);
        const char *cp;
        int dlci = 0;
        int chan;
 
#if 0
        /* Possibly start up the device if it's not already going */
        if ((xxxp->flags & SCF_RUNNING) == 0) {
                ng_xxx_start_hardware(xxxp);
        }
#endif
 
        /* Example of how one might use hooks with embedded numbers: All
         * hooks start with 'dlci' and have a decimal trailing channel
         * number up to 4 digits Use the leadin defined int he associated .h
         * file. */
        if (strncmp(name,
            NG_XXX_HOOK_DLCI_LEADIN, strlen(NG_XXX_HOOK_DLCI_LEADIN)) == 0) {
                char *eptr;
 
                cp = name + strlen(NG_XXX_HOOK_DLCI_LEADIN);
                if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
                        return (EINVAL);
                dlci = (int)strtoul(cp, &eptr, 10);
                if (*eptr != '\0' || dlci < 0 || dlci > 1023)
                        return (EINVAL);
 
                /* We have a dlci, now either find it, or allocate it */
                for (chan = 0; chan < XXX_NUM_DLCIS; chan++)
                        if (xxxp->channel[chan].dlci == dlci)
                                break;
                if (chan == XXX_NUM_DLCIS) {
                        for (chan = 0; chan < XXX_NUM_DLCIS; chan++)
                                if (xxxp->channel[chan].dlci == -2)
                                        break;
                        if (chan == XXX_NUM_DLCIS)
                                return (ENOBUFS);
                        xxxp->channel[chan].dlci = dlci;
                }
                if (xxxp->channel[chan].hook != NULL)
                        return (EADDRINUSE);
                NG_HOOK_SET_PRIVATE(hook, xxxp->channel + chan);
                xxxp->channel[chan].hook = hook;
                return (0);
        } else if (strcmp(name, NG_XXX_HOOK_DOWNSTREAM) == 0) {
                /* Example of simple predefined hooks. */
                /* do something specific to the downstream connection */
                xxxp->downstream_hook.hook = hook;
                NG_HOOK_SET_PRIVATE(hook, &xxxp->downstream_hook);
        } else if (strcmp(name, NG_XXX_HOOK_DEBUG) == 0) {
                /* do something specific to a debug connection */
                xxxp->debughook = hook;
                NG_HOOK_SET_PRIVATE(hook, NULL);
        } else
                return (EINVAL);        /* not a hook we know about */
        return(0);
}
 
/*
 * Get a netgraph control message.
 * We actually receive a queue item that has a pointer to the message.
 * If we free the item, the message will be freed too, unless we remove
 * it from the item using NGI_GET_MSG();
 * The return address is also stored in the item, as an ng_ID_t,
 * accessible as NGI_RETADDR(item);
 * Check it is one we understand. If needed, send a response.
 * We could save the address for an async action later, but don't here.
 * Always free the message.
 * The response should be in a malloc'd region that the caller can 'free'.
 * A response is not required.
 * Theoretically you could respond defferently to old message types if
 * the cookie in the header didn't match what we consider to be current
 * (so that old userland programs could continue to work).
 */
static int
ng_xxx_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        const xxx_p xxxp = NG_NODE_PRIVATE(node);
        struct ng_mesg *resp = NULL;
        int error = 0;
        struct ng_mesg *msg;
 
        NGI_GET_MSG(item, msg);
        /* Deal with message according to cookie and command */
        switch (msg->header.typecookie) {
        case NGM_XXX_COOKIE:
                switch (msg->header.cmd) {
                case NGM_XXX_GET_STATUS:
                    {
                        struct ngxxxstat *stats;
 
                        NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
                        if (!resp) {
                                error = ENOMEM;
                                break;
                        }
                        stats = (struct ngxxxstat *) resp->data;
                        stats->packets_in = xxxp->packets_in;
                        stats->packets_out = xxxp->packets_out;
                        break;
                    }
                case NGM_XXX_SET_FLAG:
                        if (msg->header.arglen != sizeof(u_int32_t)) {
                                error = EINVAL;
                                break;
                        }
                        xxxp->flags = *((u_int32_t *) msg->data);
                        break;
                default:
                        error = EINVAL;         /* unknown command */
                        break;
                }
                break;
        default:
                error = EINVAL;                 /* unknown cookie type */
                break;
        }
 
        /* Take care of synchronous response, if any */
        NG_RESPOND_MSG(error, node, item, resp);
        /* Free the message and return */
        NG_FREE_MSG(msg);
        return(error);
}
 
/*
 * Receive data, and do something with it.
 * Actually we receive a queue item which holds the data.
 * If we free the item it will also free the data unless we have
 * previously disassociated it using the NGI_GET_M() macro.
 * Possibly send it out on another link after processing.
 * Possibly do something different if it comes from different
 * hooks. The caller will never free m, so if we use up this data or
 * abort we must free it.
 *
 * If we want, we may decide to force this data to be queued and reprocessed
 * at the netgraph NETISR time.
 * We would do that by setting the HK_QUEUE flag on our hook. We would do that
 * in the connect() method.
 */
static int
ng_xxx_rcvdata(hook_p hook, item_p item )
{
        const xxx_p xxxp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        int chan = -2;
        int dlci = -2;
        int error;
        struct mbuf *m;
 
        NGI_GET_M(item, m);
        if (NG_HOOK_PRIVATE(hook)) {
                dlci = ((struct XXX_hookinfo *) NG_HOOK_PRIVATE(hook))->dlci;
                chan = ((struct XXX_hookinfo *) NG_HOOK_PRIVATE(hook))->channel;
                if (dlci != -1) {
                        /* If received on a DLCI hook process for this
                         * channel and pass it to the downstream module.
                         * Normally one would add a multiplexing header at
                         * the front here */
                        /* M_PREPEND(....)      ; */
                        /* mtod(m, xxxxxx)->dlci = dlci; */
                        NG_FWD_NEW_DATA(error, item,
                                xxxp->downstream_hook.hook, m);
                        xxxp->packets_out++;
                } else {
                        /* data came from the multiplexed link */
                        dlci = 1;       /* get dlci from header */
                        /* madjust(....) *//* chop off header */
                        for (chan = 0; chan < XXX_NUM_DLCIS; chan++)
                                if (xxxp->channel[chan].dlci == dlci)
                                        break;
                        if (chan == XXX_NUM_DLCIS) {
                                NG_FREE_ITEM(item);
                                NG_FREE_M(m);
                                return (ENETUNREACH);
                        }
                        /* If we were called at splnet, use the following:
                         * NG_SEND_DATA_ONLY(error, otherhook, m); if this
                         * node is running at some SPL other than SPLNET
                         * then you should use instead: error =
                         * ng_queueit(otherhook, m, NULL); m = NULL;
                         * This queues the data using the standard NETISR
                         * system and schedules the data to be picked
                         * up again once the system has moved to SPLNET and
                         * the processing of the data can continue. After
                         * these are run 'm' should be considered
                         * as invalid and NG_SEND_DATA actually zaps them. */
                        NG_FWD_NEW_DATA(error, item,
                                xxxp->channel[chan].hook, m);
                        xxxp->packets_in++;
                }
        } else {
                /* It's the debug hook, throw it away.. */
                if (hook == xxxp->downstream_hook.hook) {
                        NG_FREE_ITEM(item);
                        NG_FREE_M(m);
                }
        }
        return 0;
}
 
#if 0
/*
 * If this were a device node, the data may have been received in response
 * to some interrupt.
 * in which case it would probably look as follows:
 */
devintr()
{
        int error;
 
        /* get packet from device and send on */
        m = MGET(blah blah)
 
        NG_SEND_DATA_ONLY(error, xxxp->upstream_hook.hook, m);
                                /* see note above in xxx_rcvdata() */
                                /* and ng_xxx_connect() */
}
 
#endif                          /* 0 */
 
/*
 * Do local shutdown processing..
 * All our links and the name have already been removed.
 * If we are a persistent device, we might refuse to go away.
 * In the case of a persistent node we signal the framework that we
 * are still in business by clearing the NGF_INVALID bit. However
 * If we find the NGF_REALLY_DIE bit set, this means that
 * we REALLY need to die (e.g. hardware removed).
 * This would have been set using the NG_NODE_REALLY_DIE(node)
 * macro in some device dependent function (not shown here) before
 * calling ng_rmnode_self().
 */
static int
ng_xxx_shutdown(node_p node)
{
        const xxx_p privdata = NG_NODE_PRIVATE(node);
 
#ifndef PERSISTANT_NODE
        NG_NODE_SET_PRIVATE(node, NULL);
        NG_NODE_UNREF(node);
        free(privdata, M_NETGRAPH);
#else
        if (node->nd_flags & NGF_REALLY_DIE) {
                /*
                 * WE came here because the widget card is being unloaded,
                 * so stop being persistent.
                 * Actually undo all the things we did on creation.
                 */
                NG_NODE_SET_PRIVATE(node, NULL);
                NG_NODE_UNREF(privdata->node);
                free(privdata, M_NETGRAPH);
                return (0);
        }
        NG_NODE_REVIVE(node);           /* tell ng_rmnode() we will persist */
#endif /* PERSISTANT_NODE */
        return (0);
}
 
/*
 * This is called once we've already connected a new hook to the other node.
 * It gives us a chance to balk at the last minute.
 */
static int
ng_xxx_connect(hook_p hook)
{
#if 0
        /*
         * If we were a driver running at other than splnet then
         * we should set the QUEUE bit on the edge so that we
         * will deliver by queing.
         */
        if /*it is the upstream hook */
        NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));
#endif
#if 0
        /*
         * If for some reason we want incoming date to be queued
         * by the NETISR system and delivered later we can set the same bit on
         * OUR hook. (maybe to allow unwinding of the stack)
         */
 
        if (NG_HOOK_PRIVATE(hook)) {
                int dlci;
                /*
                 * If it's dlci 1023, requeue it so that it's handled
                 * at a lower priority. This is how a node decides to
                 * defer a data message.
                 */
                dlci = ((struct XXX_hookinfo *) NG_HOOK_PRIVATE(hook))->dlci;
                if (dlci == 1023) {
                        NG_HOOK_FORCE_QUEUE(hook);
                }
#endif
        /* otherwise be really amiable and just say "YUP that's OK by me! " */
        return (0);
}
 
/*
 * Hook disconnection
 *
 * For this type, removal of the last link destroys the node
 */
static int
ng_xxx_disconnect(hook_p hook)
{
        if (NG_HOOK_PRIVATE(hook))
                ((struct XXX_hookinfo *) (NG_HOOK_PRIVATE(hook)))->hook = NULL;
        if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
        && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) /* already shutting down? */
                ng_rmnode_self(NG_HOOK_NODE(hook));
        return (0);
}