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: releng/5.3/sys/netgraph/ng_sample.c 136588 2004-10-16 08:43:07Z cvs2svn $
     * $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
    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;  /* 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 = {
           .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 */
           MALLOC(privdata, xxx_p, 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;
           }
   
           /* 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 + 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);
                   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 recieve 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;
                                    * here */
   
           /* 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 persistant device, we might refuse to go away.
    * In the case of a persistant 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 persistant.
                    * 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);
   }
   

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