FreeBSD/Linux Kernel Cross Reference
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] == '' && 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);
   }
   

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