FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_etf.c

     /*-
      * ng_etf.c  Ethertype filter
      */
     
     /*-
      * Copyright (c) 2001, FreeBSD Incorporated 
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice unmodified, this list of conditions, and the following
     *    disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON 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 ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * Author: Julian Elischer <julian@freebsd.org>
     *
     * $FreeBSD: releng/7.4/sys/netgraph/ng_etf.c 143607 2005-03-14 20:49:48Z glebius $
     */
    
    #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/queue.h>
    #include <sys/syslog.h>
    
    #include <net/ethernet.h>
    
    #include <netgraph/ng_message.h>
    #include <netgraph/ng_parse.h>
    #include <netgraph/ng_etf.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_ETF, "netgraph_etf", "netgraph etf node ");
    #else
    #define M_NETGRAPH_ETF M_NETGRAPH
    #endif
    
    /*
     * This section contains the netgraph method declarations for the
     * etf node. These methods define the netgraph 'type'.
     */
    
    static ng_constructor_t ng_etf_constructor;
    static ng_rcvmsg_t      ng_etf_rcvmsg;
    static ng_shutdown_t    ng_etf_shutdown;
    static ng_newhook_t     ng_etf_newhook;
    static ng_rcvdata_t     ng_etf_rcvdata;  /* note these are both ng_rcvdata_t */
    static ng_disconnect_t  ng_etf_disconnect;
    
    /* Parse type for struct ng_etfstat */
    static const struct ng_parse_struct_field ng_etf_stat_type_fields[]
            = NG_ETF_STATS_TYPE_INFO;
    static const struct ng_parse_type ng_etf_stat_type = {
            &ng_parse_struct_type,
            &ng_etf_stat_type_fields
    };
    /* Parse type for struct ng_setfilter */
    static const struct ng_parse_struct_field ng_etf_filter_type_fields[]
            = NG_ETF_FILTER_TYPE_INFO;
    static const struct ng_parse_type ng_etf_filter_type = {
            &ng_parse_struct_type,
            &ng_etf_filter_type_fields
    };
    
    /* List of commands and how to convert arguments to/from ASCII */
    static const struct ng_cmdlist ng_etf_cmdlist[] = {
            {
              NGM_ETF_COOKIE,
              NGM_ETF_GET_STATUS,
              "getstatus",
              NULL,
              &ng_etf_stat_type,
            },
            {
              NGM_ETF_COOKIE,
              NGM_ETF_SET_FLAG,
             "setflag",
             &ng_parse_int32_type,
             NULL
           },
           {
             NGM_ETF_COOKIE,
             NGM_ETF_SET_FILTER,
             "setfilter",
             &ng_etf_filter_type,
             NULL
           },
           { 0 }
   };
   
   /* Netgraph node type descriptor */
   static struct ng_type typestruct = {
           .version =      NG_ABI_VERSION,
           .name =         NG_ETF_NODE_TYPE,
           .constructor =  ng_etf_constructor,
           .rcvmsg =       ng_etf_rcvmsg,
           .shutdown =     ng_etf_shutdown,
           .newhook =      ng_etf_newhook,
           .rcvdata =      ng_etf_rcvdata,
           .disconnect =   ng_etf_disconnect,
           .cmdlist =      ng_etf_cmdlist,
   };
   NETGRAPH_INIT(etf, &typestruct);
   
   /* Information we store for each hook on each node */
   struct ETF_hookinfo {
           hook_p  hook;
   };
   
   struct filter {
           LIST_ENTRY(filter) next;
           u_int16_t       ethertype;      /* network order ethertype */
           hook_p          match_hook;     /* Hook to use on a match */
   };
   
   #define HASHSIZE 16 /* Dont change this without changing HASH() */
   #define HASH(et) ((((et)>>12)+((et)>>8)+((et)>>4)+(et)) & 0x0f)
   LIST_HEAD(filterhead, filter);
   
   /* Information we store for each node */
   struct ETF {
           struct ETF_hookinfo downstream_hook;
           struct ETF_hookinfo nomatch_hook;
           node_p          node;           /* back pointer to node */
           u_int           packets_in;     /* packets in from downstream */
           u_int           packets_out;    /* packets out towards downstream */
           u_int32_t       flags;
           struct filterhead hashtable[HASHSIZE];
   };
   typedef struct ETF *etf_p;
   
   static struct filter *
   ng_etf_findentry(etf_p etfp, u_int16_t ethertype)
   {
           struct filterhead *chain = etfp->hashtable + HASH(ethertype);
           struct filter *fil;
           
   
           LIST_FOREACH(fil, chain, next) {
                   if (fil->ethertype == ethertype) {
                           return (fil);
                   }
           }
           return (NULL);
   }
   
   
   /*
    * 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.
    */
   static int
   ng_etf_constructor(node_p node)
   {
           etf_p privdata;
           int i;
   
           /* Initialize private descriptor */
           MALLOC(privdata, etf_p, sizeof(*privdata), M_NETGRAPH_ETF,
                   M_NOWAIT | M_ZERO);
           if (privdata == NULL)
                   return (ENOMEM);
           for (i = 0; i < HASHSIZE; i++) {
                   LIST_INIT((privdata->hashtable + i));
           }
   
           /* Link structs together; this counts as our one reference to node */
           NG_NODE_SET_PRIVATE(node, privdata);
           privdata->node = node;
           return (0);
   }
   
   /*
    * Give our ok for a hook to be added...
    * All names are ok. Two names are special.
    */
   static int
   ng_etf_newhook(node_p node, hook_p hook, const char *name)
   {
           const etf_p etfp = NG_NODE_PRIVATE(node);
           struct ETF_hookinfo *hpriv;
   
           if (strcmp(name, NG_ETF_HOOK_DOWNSTREAM) == 0) {
                   etfp->downstream_hook.hook = hook;
                   NG_HOOK_SET_PRIVATE(hook, &etfp->downstream_hook);
                   etfp->packets_in = 0;
                   etfp->packets_out = 0;
           } else if (strcmp(name, NG_ETF_HOOK_NOMATCH) == 0) {
                   etfp->nomatch_hook.hook = hook;
                   NG_HOOK_SET_PRIVATE(hook, &etfp->nomatch_hook);
           } else {
                   /*
                    * Any other hook name is valid and can
                    * later be associated with a filter rule.
                    */
                   MALLOC(hpriv, struct ETF_hookinfo *, sizeof(*hpriv),
                           M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
                   if (hpriv == NULL) {
                           return (ENOMEM);
                   }
   
                   NG_HOOK_SET_PRIVATE(hook, hpriv);
                   hpriv->hook = hook;
           }
           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'.
    * The NG_MKRESPONSE macro does all this for us.
    * 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_etf_rcvmsg(node_p node, item_p item, hook_p lasthook)
   {
           const etf_p etfp = 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_ETF_COOKIE: 
                   switch (msg->header.cmd) {
                   case NGM_ETF_GET_STATUS:
                       {
                           struct ng_etfstat *stats;
   
                           NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
                           if (!resp) {
                                   error = ENOMEM;
                                   break;
                           }
                           stats = (struct ng_etfstat *) resp->data;
                           stats->packets_in = etfp->packets_in;
                           stats->packets_out = etfp->packets_out;
                           break;
                       }
                   case NGM_ETF_SET_FLAG:
                           if (msg->header.arglen != sizeof(u_int32_t)) {
                                   error = EINVAL;
                                   break;
                           }
                           etfp->flags = *((u_int32_t *) msg->data);
                           break;
                   case NGM_ETF_SET_FILTER:
                           {
                                   struct ng_etffilter *f;
                                   struct filter *fil;
                                   hook_p  hook;
   
                                   /* Check message long enough for this command */
                                   if (msg->header.arglen != sizeof(*f)) {
                                           error = EINVAL;
                                           break;
                                   }
   
                                   /* Make sure hook referenced exists */
                                   f = (struct ng_etffilter *)msg->data;
                                   hook = ng_findhook(node, f->matchhook);
                                   if (hook == NULL) {
                                           error = ENOENT;
                                           break;
                                   }
   
                                   /* and is not the downstream hook */
                                   if (hook == etfp->downstream_hook.hook) {
                                           error = EINVAL;
                                           break;
                                   }
   
                                   /* Check we don't already trap this ethertype */
                                   if (ng_etf_findentry(etfp,
                                                   htons(f->ethertype))) {
                                           error = EEXIST;
                                           break;
                                   }
   
                                   /*
                                    * Ok, make the filter and put it in the 
                                    * hashtable ready for matching.
                                    */
                                   MALLOC(fil, struct filter *, sizeof(*fil),
                                           M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
                                   if (fil == NULL) {
                                           error = ENOMEM;
                                           break;
                                   }
   
                                   fil->match_hook = hook;
                                   fil->ethertype = htons(f->ethertype);
                                   LIST_INSERT_HEAD( etfp->hashtable
                                           + HASH(fil->ethertype),
                                                   fil, next);
                           }
                           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_etf() 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_etf_rcvdata(hook_p hook, item_p item )
   {
           const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
           struct ether_header *eh;
           int error = 0;
           struct mbuf *m;
           u_int16_t ethertype;
           struct filter *fil;
   
           if (NG_HOOK_PRIVATE(hook) == NULL) { /* Shouldn't happen but.. */
                   NG_FREE_ITEM(item);
           }
   
           /* 
            * Everything not from the downstream hook goes to the
            * downstream hook. But only if it matches the ethertype
            * of the source hook. Un matching must go to/from 'nomatch'.
            */
   
           /* Make sure we have an entire header */
           NGI_GET_M(item, m);
           if (m->m_len < sizeof(*eh) ) {
                   m = m_pullup(m, sizeof(*eh));
                   if (m == NULL) {
                           NG_FREE_ITEM(item);
                           return(EINVAL);
                   }
           }
   
           eh = mtod(m, struct ether_header *);
           ethertype = eh->ether_type;
           fil = ng_etf_findentry(etfp, ethertype);
   
           /*
            * if from downstream, select between a match hook or
            * the nomatch hook
            */
           if (hook == etfp->downstream_hook.hook) {
                   etfp->packets_in++;
                   if (fil && fil->match_hook) {
                           NG_FWD_NEW_DATA(error, item, fil->match_hook, m);
                   } else {
                           NG_FWD_NEW_DATA(error, item,etfp->nomatch_hook.hook, m);
                   }
           } else {
                   /* 
                    * It must be heading towards the downstream.
                    * Check that it's ethertype matches 
                    * the filters for it's input hook.
                    * If it doesn't have one, check it's from nomatch.
                    */
                   if ((fil && (fil->match_hook != hook))
                   || ((fil == NULL) && (hook != etfp->nomatch_hook.hook))) {
                           NG_FREE_ITEM(item);
                           NG_FREE_M(m);
                           return (EPROTOTYPE);
                   }
                   NG_FWD_NEW_DATA( error, item, etfp->downstream_hook.hook, m);
                   if (error == 0) {
                           etfp->packets_out++;
                   }
           }
           return (error);
   }
   
   /*
    * Do local shutdown processing..
    * All our links and the name have already been removed.
    */
   static int
   ng_etf_shutdown(node_p node)
   {
           const etf_p privdata = NG_NODE_PRIVATE(node);
   
           NG_NODE_SET_PRIVATE(node, NULL);
           NG_NODE_UNREF(privdata->node);
           FREE(privdata, M_NETGRAPH_ETF);
           return (0);
   }
   
   /*
    * Hook disconnection
    *
    * For this type, removal of the last link destroys the node
    */
   static int
   ng_etf_disconnect(hook_p hook)
   {
           const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
           int i;
           struct filter *fil1, *fil2;
   
           /* purge any rules that refer to this filter */
           for (i = 0; i < HASHSIZE; i++) {
                   fil1 = LIST_FIRST(&etfp->hashtable[i]);
                   while (fil1 != NULL) {
                           fil2 = LIST_NEXT(fil1, next);
                           if (fil1->match_hook == hook) {
                                   LIST_REMOVE(fil1, next);
                                   FREE(fil1, M_NETGRAPH_ETF);
                           }
                           fil1 = fil2;
                   }
           }
                   
           /* If it's not one of the special hooks, then free it */
           if (hook == etfp->downstream_hook.hook) {
                   etfp->downstream_hook.hook = NULL;
           } else if (hook == etfp->nomatch_hook.hook) {
                   etfp->nomatch_hook.hook = NULL;
           } else {
                   if (NG_HOOK_PRIVATE(hook)) /* Paranoia */
                           FREE(NG_HOOK_PRIVATE(hook), M_NETGRAPH_ETF);
           }
   
           NG_HOOK_SET_PRIVATE(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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