FreeBSD/Linux Kernel Cross Reference
sys/net/bridge.h

     /*
      * Copyright (c) 1998 Luigi Rizzo
      *
      * 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, 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 REGENTS 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 REGENTS 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.
     *
     */
    
    extern int do_bridge;
    /*
     * the hash table for bridge
     */
    typedef struct hash_table {
        struct ifnet *name ;
        u_char etheraddr[6] ;
        u_short used ;
    } bdg_hash_table ;
    
    extern bdg_hash_table *bdg_table ;
    
    #define BDG_MAX_PORTS 128
    extern unsigned char bdg_addresses[6*BDG_MAX_PORTS];
    extern int bdg_ports ;
    
    /*
     * out of the 6 bytes, the last ones are more "variable". Since
     * we are on a little endian machine, we have to do some gimmick...
     */
    #define HASH_SIZE 8192  /* must be a power of 2 */
    #define HASH_FN(addr)   (       \
            ntohs( ((short *)addr)[1] ^ ((short *)addr)[2] ) & (HASH_SIZE -1))
    
    #define IFF_MUTE        IFF_LINK2       /* will need a separate flag... */
    
    struct ifnet *bridge_in(struct mbuf *m);
    /* bdg_forward frees the mbuf if necessary, returning null */
    int bdg_forward (struct mbuf **m, struct ifnet *dst);
    
    #ifdef __i386__
    #define BDG_MATCH(a,b) ( \
        ((unsigned short *)(a))[2] == ((unsigned short *)(b))[2] && \
        *((unsigned int *)(a)) == *((unsigned int *)(b)) )
    #define IS_ETHER_BROADCAST(a) ( \
            *((unsigned int *)(a)) == 0xffffffff && \
            ((unsigned short *)(a))[2] == 0xffff )
    #else
    #warning... must complete these for the alpha etc.
    #define BDG_MATCH(a,b) (!bcmp(a, b, ETHER_ADDR_LEN) )
    #endif
    /*
     * The following constants are not legal ifnet pointers, and are used
     * as return values from the classifier, bridge_dst_lookup()
     * The same values are used as index in the statistics arrays,
     * with BDG_FORWARD replacing specifically forwarded packets.
     */
    #define BDG_BCAST       ( (struct ifnet *)1 )
    #define BDG_MCAST       ( (struct ifnet *)2 )
    #define BDG_LOCAL       ( (struct ifnet *)3 )
    #define BDG_DROP        ( (struct ifnet *)4 )
    #define BDG_UNKNOWN     ( (struct ifnet *)5 )
    #define BDG_IN          ( (struct ifnet *)7 )
    #define BDG_OUT         ( (struct ifnet *)8 )
    #define BDG_FORWARD     ( (struct ifnet *)9 )
    
    #define PF_BDG 3 /* XXX superhack */
    /*
     * statistics, passed up with sysctl interface and ns -p bdg
     */
    
    #define STAT_MAX (int)BDG_FORWARD
    struct bdg_port_stat {
        char name[16];
        u_long collisions;
        u_long p_in[STAT_MAX+1];
    } ;
    
    struct bdg_stats {
        struct bdg_port_stat s[16];
    } ;
    
    
   #define BDG_STAT(ifp, type) bdg_stats.s[ifp->if_index].p_in[(int)type]++ 
    
   #ifdef KERNEL
   /*
    * Find the right pkt destination:
    *      BDG_BCAST       is a broadcast
    *      BDG_MCAST       is a multicast
    *      BDG_LOCAL       is for a local address
    *      BDG_DROP        must be dropped
    *      other           ifp of the dest. interface (incl.self)
    */
   static inline
   struct ifnet *
   bridge_dst_lookup(struct mbuf *m)
   {
       struct ether_header *eh = mtod(m, struct ether_header *);
       struct ifnet *dst ;
       int index ;
       u_char *eth_addr = bdg_addresses ;
   
       if (IS_ETHER_BROADCAST(eh->ether_dhost))
           return BDG_BCAST ;
       if (eh->ether_dhost[0] & 1)
           return BDG_MCAST ;
       /*
        * Lookup local addresses in case one matches.
        */
       for (index = bdg_ports, eth_addr = bdg_addresses ;
                    index ; index--, eth_addr += 6 )
           if (BDG_MATCH(eth_addr, eh->ether_dhost) )
               return BDG_LOCAL ;
       /*
        * Look for a possible destination in table
        */
       index= HASH_FN( eh->ether_dhost );
       dst = bdg_table[index].name;
       if ( dst && BDG_MATCH( bdg_table[index].etheraddr, eh->ether_dhost) )
           return dst ;
       else
           return BDG_UNKNOWN ;
   }
   
   #endif /* KERNEL */

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