Lots of improvement to the bridging code.

In order of importance:

 + each cluster now uses private data structures (filtering and
   local address tables) so you can treat them as fully independent
   switches. This part of the work was supported by:
        Cisco Systems, Inc. - NSITE lab, RTP, NC.

 + cleaned up the handling of configuration, so the system will behave
   much better when real or pseudo devices are dynamically attached
   or detached. It should also not panic anymore on systems with large
   number of devices, closing a few existings PRs on the topic.

 + while at it, add support for VLAN. This means that a FreeBSD box
   can now work as a real VLAN switch, with trunk interfaces etc.
   As an example:
        ifconfig vlan0 vlan 3 vlandev dc0
        ifconfig vlan1 vlan 4 vlandev dc0
        net.link.ether.bridge_cfg="vlan0:3,dc1:3,vlan1:4,dc1:4"
   uses dc0 as a trunk interface, and dc1 and dc3 as ports on vlans 3 and 4
   You get the idea...
   NOTA BENE: by default bridge_cfg is initialised to "" so even if
   you enable bridging, no packets will be bridged until you set the
   list of interfaces on which you want this to happen.

 + large restructuring of the code, moving private vars and types from
   bridge.h to bridge.c.

 + added a lot of comments to the code to explain how to use it.

1 files changed, 25 insertions, 60 deletions

diff --git a/sys/net/bridge.h b/sys/net/bridge.h
index 33b9cda..37dcb5d 100644
--- a/sys/net/bridge.h
+++ b/sys/net/bridge.h
@@ -1,5 +1,7 @@
 /*
- * Copyright (c) 1998-2000 Luigi Rizzo
+ * Copyright (c) 1998-2002 Luigi Rizzo
+ *
+ * Work partly supported by: Cisco Systems, Inc. - NSITE lab, RTP, NC
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -26,86 +28,45 @@
  */
 
 extern int do_bridge;
-/*
- * the hash table for bridge
- */
-typedef struct hash_table {
-    struct ifnet *name ;
-    unsigned char etheraddr[6] ;
-    unsigned short used ;
-} bdg_hash_table ;
-
-extern bdg_hash_table *bdg_table ;
 
 /*
- * We need additional info for the bridge. The bdg_ifp2sc[] array
- * provides a pointer to this struct using the if_index.   
+ * We need additional per-interface info for the bridge, which is
+ * stored in a struct bdg_softc. The ifp2sc[] array provides a pointer
+ * to this struct using the if_index as a mapping key.
  * bdg_softc has a backpointer to the struct ifnet, the bridge
  * flags, and a cluster (bridging occurs only between port of the
  * same cluster).
  */
+
+struct cluster_softc;	/* opaque here, defined in bridge.c */
+
 struct bdg_softc {
     struct ifnet *ifp ;
     /* also ((struct arpcom *)ifp)->ac_enaddr is the eth. addr */
     int flags ;
-#define IFF_BDG_PROMISC 0x0001  /* set promisc mode on this if.  */
+#define IFF_BDG_PROMISC 0x0001  /* set promisc mode on this if.	*/
 #define IFF_MUTE        0x0002  /* mute this if for bridging.   */
 #define IFF_USED        0x0004  /* use this if for bridging.    */
-    short cluster_id ; /* in network format */
-    u_long magic;
+    struct cluster_softc *cluster;
 } ;
 
 extern struct bdg_softc *ifp2sc;
 
 #define BDG_USED(ifp) (ifp2sc[ifp->if_index].flags & IFF_USED)
-#define BDG_MUTED(ifp) (ifp2sc[ifp->if_index].flags & IFF_MUTE)
-#define BDG_MUTE(ifp) ifp2sc[ifp->if_index].flags |= IFF_MUTE
-#define BDG_UNMUTE(ifp) ifp2sc[ifp->if_index].flags &= ~IFF_MUTE
-#define BDG_CLUSTER(ifp) (ifp2sc[ifp->if_index].cluster_id)
-#define BDG_EH(ifp)	((struct arpcom *)ifp)->ac_enaddr
-
-#define BDG_SAMECLUSTER(ifp,src) \
-	(src == NULL || BDG_CLUSTER(ifp) == BDG_CLUSTER(src) )
-
 /*
- * BDG_ACTIVE(ifp) does all checks to see if bridging is loaded,
- * activated and used on a given interface.
+ * BDG_ACTIVE(ifp) does all checks to see if bridging is enabled, loaded,
+ * and used on a given interface.
  */
 #define	BDG_ACTIVE(ifp)	(do_bridge && BDG_LOADED && BDG_USED(ifp))
 
-#define BDG_MAX_PORTS 128
-typedef struct _bdg_addr {
-    unsigned char etheraddr[6] ;
-    short cluster_id ;
-} bdg_addr ;
-extern bdg_addr bdg_addresses[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))
-
-#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
-/* for machines that do not support unaligned access */
-#define BDG_MATCH(a,b)		(!bcmp(a, b, ETHER_ADDR_LEN) )
-#define	IS_ETHER_BROADCAST(a)	(!bcmp(a, "\377\377\377\377\377\377", 6))
-#endif
 /*
  * The following constants are not legal ifnet pointers, and are used
- * as return values from the classifier, bridge_dst_lookup()
+ * 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.
+ *
+ * These constants are here because they are used in 'netstat'
+ * to show bridge statistics.
  */
 #define BDG_BCAST	( (struct ifnet *)1 )
 #define BDG_MCAST	( (struct ifnet *)2 )
@@ -116,11 +77,13 @@ extern int bdg_ports ;
 #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
+ * Statistics are passed up with the sysctl interface, "netstat -p bdg"
+ * reads them. PF_BDG defines the 'bridge' protocol family.
  */
 
+#define PF_BDG 3 /* XXX superhack */
+
 #define STAT_MAX (int)BDG_FORWARD
 struct bdg_port_stat {
     char name[16];
@@ -128,12 +91,14 @@ struct bdg_port_stat {
     u_long p_in[STAT_MAX+1];
 } ;
 
+/* XXX this should be made dynamic */
+#define BDG_MAX_PORTS 128
 struct bdg_stats {
-    struct bdg_port_stat s[16];
+    struct bdg_port_stat s[BDG_MAX_PORTS];
 } ;
 
 
-#define BDG_STAT(ifp, type) bdg_stats.s[ifp->if_index].p_in[(long)type]++ 
+#define BDG_STAT(ifp, type) bdg_stats.s[ifp->if_index].p_in[(uintptr_t)type]++ 
  
 #ifdef _KERNEL
 typedef	struct ifnet *bridge_in_t(struct ifnet *, struct ether_header *);