hammer2 - Fix flush issues with unmounted PFSs and shutdown panic

[dragonfly.git] / sys / netgraph / ng_sample.c

/*
 * 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: src/sys/netgraph/ng_sample.c,v 1.7.2.3 2002/07/02 23:44:03 archie Exp $
 * $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>

/*
 * 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_rmnode;
static ng_newhook_t     ng_xxx_newhook;
static ng_connect_t     ng_xxx_connect;
static ng_rcvdata_t     ng_xxx_rcvdata;  /* note these are both ng_rcvdata_t */
static ng_rcvdata_t     ng_xxx_rcvdataq; /* note these are both ng_rcvdata_t */
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 = {
        NG_VERSION,
        NG_XXX_NODE_TYPE,
        NULL,
        ng_xxx_constructor,
        ng_xxx_rcvmsg,
        ng_xxx_rmnode,
        ng_xxx_newhook,
        NULL,
        ng_xxx_connect,
        ng_xxx_rcvdata,
        ng_xxx_rcvdataq,
        ng_xxx_disconnect,
        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 and the generic node
 * and link them together.
 *
 * ng_make_node_common() returns with a generic node struct
 * with a single reference for us.. we transfer it to the
 * private structure.. when we free the private struct we must
 * unref the node so it gets freed too.
 *
 * 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 *nodep)
{
        xxx_p privdata;
        int i, error;

        /* Initialize private descriptor */
        privdata = kmalloc(sizeof(*privdata), M_NETGRAPH, M_NOWAIT | M_ZERO);
        if (privdata == NULL)
                return (ENOMEM);
        for (i = 0; i < XXX_NUM_DLCIS; i++) {
                privdata->channel[i].dlci = -2;
                privdata->channel[i].channel = i;
        }

        /* Call the 'generic' (ie, superclass) node constructor */
        if ((error = ng_make_node_common(&typestruct, nodep))) {
                kfree(privdata, M_NETGRAPH);
                return (error);
        }

        /* Link structs together; this counts as our one reference to *nodep */
        (*nodep)->private = privdata;
        privdata->node = *nodep;
        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 = node->private;
        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 + sizeof(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)
                                        continue;
                        if (chan == XXX_NUM_DLCIS)
                                return (ENOBUFS);
                }
                if (xxxp->channel[chan].hook != NULL)
                        return (EADDRINUSE);
                hook->private = 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;
                hook->private = &xxxp->downstream_hook;
        } else if (strcmp(name, NG_XXX_HOOK_DEBUG) == 0) {
                /* do something specific to a debug connection */
                xxxp->debughook = hook;
                hook->private = NULL;
        } else
                return (EINVAL);        /* not a hook we know about */
        return(0);
}

/*
 * Get a netgraph control message.
 * 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,
           struct ng_mesg *msg, const char *retaddr, struct ng_mesg **rptr)
{
        const xxx_p xxxp = node->private;
        struct ng_mesg *resp = NULL;
        int error = 0;

        /* 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 */
        if (rptr)
                *rptr = resp;
        else if (resp)
                kfree(resp, M_NETGRAPH);

        /* Free the message and return */
        kfree(msg, M_NETGRAPH);
        return(error);
}

/*
 * Receive data, and do something with it.
 * 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 or meta, so
 * if we use up this data or abort we must free BOTH of these.
 *
 * If we want, we may decide to force this data to be queued and reprocessed
 * at the netgraph NETISR time. (at which time it will be entered using ng_xxx_rcvdataq().
 */
static int
ng_xxx_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
{
        int dlci = -2;

        if (hook->private) {
                /* 
                 * 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 *) hook->private)->dlci;
                if (dlci == 1023) {
                        return(ng_queue_data(hook->peer, m, meta));
                }
        }
        return(ng_xxx_rcvdataq(hook, m, meta));
}

/*
 * Always accept the data. This version of rcvdata is called from the dequeueing routine.
 */
static int
ng_xxx_rcvdataq(hook_p hook, struct mbuf *m, meta_p meta)
{
        const xxx_p xxxp = hook->node->private;
        int chan = -2;
        int dlci = -2;
        int error;

        if (hook->private) {
                dlci = ((struct XXX_hookinfo *) hook->private)->dlci;
                chan = ((struct XXX_hookinfo *) hook->private)->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; */
                        error = ng_send_data(xxxp->downstream_hook.hook,
                            m, meta);
                        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_DATA(m, meta);
                                return (ENETUNREACH);
                        }
                        /* If we were called at splnet, use the following:
                         * NG_SEND_DATA(error, otherhook, m, meta); if this
                         * node is running at some SPL other than SPLNET
                         * then you should use instead: error =
                         * ng_queueit(otherhook, m, meta); m = NULL: meta =
                         * 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' and 'meta' should be considered
                         * as invalid and NG_SEND_DATA actually zaps them. */
                        NG_SEND_DATA(error, xxxp->channel[chan].hook, m, meta);
                        xxxp->packets_in++;
                }
        } else {
                /* It's the debug hook, throw it away.. */
                if (hook == xxxp->downstream_hook.hook)
                        NG_FREE_DATA(m, meta);
        }
        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:
 */
void
devintr(void)
{
        meta_p  meta = NULL;    /* whatever metadata we might imagine goes
                                 * here */

        /* get packet from device and send on */
        m = MGET(blah blah)
            error = ng_queueit(upstream, m, meta);      /* see note above in
                                                         * xxx_rcvdata() */
}

#endif                          /* 0 */

/*
 * Do local shutdown processing..
 * If we are a persistant device, we might refuse to go away, and
 * we'd only remove our links and reset ourself.
 */
static int
ng_xxx_rmnode(node_p node)
{
        const xxx_p privdata = node->private;

        node->flags |= NG_INVALID;
        ng_cutlinks(node);
#ifndef PERSISTANT_NODE
        ng_unname(node);
        node->private = NULL;
        ng_unref(privdata->node);
        kfree(privdata, M_NETGRAPH);
#else
        privdata->packets_in = 0;               /* reset stats */
        privdata->packets_out = 0;
        node->flags &= ~NG_INVALID;             /* reset invalid flag */
#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)
{
        /* be really amiable and just say "YUP that's OK by me! " */
        return (0);
}

/*
 * Dook disconnection
 *
 * For this type, removal of the last link destroys the node
 */
static int
ng_xxx_disconnect(hook_p hook)
{
        if (hook->private)
                ((struct XXX_hookinfo *) (hook->private))->hook = NULL;
        if (hook->node->numhooks == 0)
                ng_rmnode(hook->node);
        return (0);
}