patch-1.3.86 linux/net/bridge/br.c

Next file: linux/net/bridge/br_tree.c
Previous file: linux/net/bridge/Makefile
Back to the patch index
Back to the overall index

diff -u --recursive --new-file v1.3.85/linux/net/bridge/br.c linux/net/bridge/br.c
@@ -0,0 +1,1561 @@
+/*
+ *	Linux NET3 Bridge Support
+ *
+ *	Originally by John Hayes (Network Plumbing).
+ *	Minor hacks to get it to run with 1.3.x by Alan Cox <Alan.Cox@linux.org>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ *	Fixes:
+ *
+ *	Todo:
+ *		Don't bring up devices automatically. Start ports disabled
+ *	and use a netlink notifier so a daemon can maintain the bridge
+ *	port group (could we also do multiple groups ????).
+ *		A nice /proc file interface.
+ *		Put the path costs in the port info and devices
+ *		Put the bridge port number in the device structure for speed.
+ *	
+ */
+ 
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <asm/segment.h>
+#include <asm/system.h>
+#include <net/br.h>
+
+static int br_device_event(struct notifier_block *dnot, unsigned long event, void *ptr);
+static void br_tick(unsigned long arg);
+int br_forward(struct sk_buff *skb, int port);	/* 3.7 */
+int br_port_cost(struct device *dev);	/* 4.10.2 */
+void br_bpdu(struct sk_buff *skb); /* consumes skb */
+int br_tx_frame(struct sk_buff *skb);
+int br_cmp(unsigned int *a, unsigned int *b);
+
+unsigned char bridge_ula[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
+
+Bridge_data     bridge_info;			  /* (4.5.3)	 */
+Port_data       port_info[All_ports];		  /* (4.5.5)	 */
+Config_bpdu     config_bpdu[All_ports];
+Tcn_bpdu        tcn_bpdu[All_ports];
+Timer           hello_timer;			  /* (4.5.4.1)	 */
+Timer           tcn_timer;			  /* (4.5.4.2)	 */
+Timer           topology_change_timer;		  /* (4.5.4.3)	 */
+Timer           message_age_timer[All_ports];	  /* (4.5.6.1)	 */
+Timer           forward_delay_timer[All_ports];	  /* (4.5.6.2)	 */
+Timer           hold_timer[All_ports];		  /* (4.5.6.3)	 */
+
+/* entries timeout after this many seconds */
+unsigned int fdb_aging_time = FDB_TIMEOUT; 
+
+struct br_stat br_stats;
+
+static struct timer_list tl; /* for 1 second timer... */
+
+/*
+ * the following structure is required so that we receive
+ * event notifications when network deviced are enabled and
+ * disabled (ifconfig up and down).
+ */
+static struct notifier_block br_dev_notifier={
+	br_device_event,
+	NULL,
+	0
+};
+
+/** Elements of Procedure (4.6) **/
+
+/*
+ * this section of code was gratiously borrowed from the IEEE 802.1d
+ * specification section 4.9.1 starting on pg 69.  It has been
+ * modified somewhat to fit within out framework and structure.  It
+ * implements the spanning tree algorithm that is the heart of the
+ * 802.1d bridging protocol.
+ */
+
+void
+transmit_config(int port_no)			  /* (4.6.1)	 */
+{
+	if (hold_timer[port_no].active) {	  /* (4.6.1.3.1)	 */
+		port_info[port_no].config_pending = TRUE;	/* (4.6.1.3.1)	 */
+	} else {				  /* (4.6.1.3.2)	 */
+		config_bpdu[port_no].type = BPDU_TYPE_CONFIG;
+		config_bpdu[port_no].root_id = bridge_info.designated_root;
+		/* (4.6.1.3.2(1)) */
+		config_bpdu[port_no].root_path_cost = bridge_info.root_path_cost;
+		/* (4.6.1.3.2(2)) */
+		config_bpdu[port_no].bridge_id = bridge_info.bridge_id;
+		/* (4.6.1.3.2(3)) */
+		config_bpdu[port_no].port_id = port_info[port_no].port_id;
+		/*
+		 * (4.6.1.3.2(4))
+		 */
+		if (root_bridge()) {
+			config_bpdu[port_no].message_age = Zero;	/* (4.6.1.3.2(5)) */
+		} else {
+			config_bpdu[port_no].message_age
+				= message_age_timer[bridge_info.root_port].value
+				+ Message_age_increment;	/* (4.6.1.3.2(6)) */
+		}
+
+		config_bpdu[port_no].max_age = bridge_info.max_age;	/* (4.6.1.3.2(7)) */
+		config_bpdu[port_no].hello_time = bridge_info.hello_time;
+		config_bpdu[port_no].forward_delay = bridge_info.forward_delay;
+		config_bpdu[port_no].flags = 0;
+		config_bpdu[port_no].flags |=
+			port_info[port_no].top_change_ack ? TOPOLOGY_CHANGE_ACK : 0;
+		/* (4.6.1.3.2(8)) */
+		port_info[port_no].top_change_ack = 0;
+		/* (4.6.1.3.2(8)) */
+		config_bpdu[port_no].flags |=
+			bridge_info.top_change ? TOPOLOGY_CHANGE : 0;
+		/* (4.6.1.3.2(9)) */
+
+		send_config_bpdu(port_no, &config_bpdu[port_no]);
+		port_info[port_no].config_pending = FALSE;	/* (4.6.1.3.2(10)) */
+		start_hold_timer(port_no);	  /* (4.6.1.3.2(11)) */
+	}
+}
+
+int
+root_bridge(void)
+{
+	return (br_cmp(bridge_info.designated_root.BRIDGE_ID,
+		 bridge_info.bridge_id.BRIDGE_ID)?FALSE:TRUE);
+}
+
+int
+supersedes_port_info(int port_no, Config_bpdu *config)	  /* (4.6.2.2)	 */
+{
+	return (
+		(br_cmp(config->root_id.BRIDGE_ID,
+		 port_info[port_no].designated_root.BRIDGE_ID) < 0)	/* (4.6.2.2.1)	 */ 
+		||
+		((br_cmp(config->root_id.BRIDGE_ID,
+		  port_info[port_no].designated_root.BRIDGE_ID) == 0
+		  )
+		 &&
+		 ((config->root_path_cost
+		   < port_info[port_no].designated_cost	/* (4.6.2.2.2)	 */
+		   )
+		  ||
+		  ((config->root_path_cost
+		    == port_info[port_no].designated_cost
+		    )
+		   &&
+		   ((br_cmp(config->bridge_id.BRIDGE_ID,
+		     port_info[port_no].designated_bridge.BRIDGE_ID) < 0	/* (4.6.2.2.3)    */
+		     )
+		    ||
+		    ((br_cmp(config->bridge_id.BRIDGE_ID,
+		      port_info[port_no].designated_bridge.BRIDGE_ID) == 0
+		      )				  /* (4.6.2.2.4)	 */
+		     &&
+		     ((br_cmp(config->bridge_id.BRIDGE_ID,
+			bridge_info.bridge_id.BRIDGE_ID) != 0
+		       )			  /* (4.6.2.2.4(1)) */
+		      ||
+		      (config->port_id <=
+		       port_info[port_no].designated_port
+		       )			  /* (4.6.2.2.4(2)) */
+		      ))))))
+		);
+}
+
+void
+record_config_information(int port_no, Config_bpdu *config)	  /* (4.6.2)	 */
+{
+	port_info[port_no].designated_root = config->root_id;	/* (4.6.2.3.1)   */
+	port_info[port_no].designated_cost = config->root_path_cost;
+	port_info[port_no].designated_bridge = config->bridge_id;
+	port_info[port_no].designated_port = config->port_id;
+	start_message_age_timer(port_no, config->message_age);	/* (4.6.2.3.2)   */
+}
+
+void
+record_config_timeout_values(Config_bpdu *config)		  /* (4.6.3)	 */
+{
+	bridge_info.max_age = config->max_age;	  /* (4.6.3.3)	 */
+	bridge_info.hello_time = config->hello_time;
+	bridge_info.forward_delay = config->forward_delay;
+	if (config->flags & TOPOLOGY_CHANGE)
+		bridge_info.top_change = 1;
+}
+
+void
+config_bpdu_generation(void)
+{						  /* (4.6.4)	 */
+	int             port_no;
+	for (port_no = One; port_no <= No_of_ports; port_no++) {	/* (4.6.4.3) */
+		if (designated_port(port_no)	  /* (4.6.4.3)	 */
+				&&
+				(port_info[port_no].state != Disabled)
+			) {
+			transmit_config(port_no); /* (4.6.4.3)	 */
+		}				  /* (4.6.1.2)	 */
+	}
+}
+
+int
+designated_port(int port_no)
+{
+	return ((br_cmp(port_info[port_no].designated_bridge.BRIDGE_ID,
+		 bridge_info.bridge_id.BRIDGE_ID) == 0
+		 )
+		&&
+		(port_info[port_no].designated_port
+		 == port_info[port_no].port_id
+		 )
+		);
+}
+
+void
+reply(int port_no)					  /* (4.6.5)	 */
+{
+	transmit_config(port_no);		  /* (4.6.5.3)	 */
+}
+
+void
+transmit_tcn(void)
+{						  /* (4.6.6)	 */
+	int             port_no;
+
+	port_no = bridge_info.root_port;
+	tcn_bpdu[port_no].type = BPDU_TYPE_TOPO_CHANGE;
+	send_tcn_bpdu(port_no, &tcn_bpdu[bridge_info.root_port]);	/* (4.6.6.3)     */
+}
+
+void
+configuration_update(void)	/* (4.6.7) */
+{
+	root_selection();			  /* (4.6.7.3.1)	 */
+	/* (4.6.8.2)	 */
+	designated_port_selection();		  /* (4.6.7.3.2)	 */
+	/* (4.6.9.2)	 */
+}
+
+void
+root_selection(void)
+{						  /* (4.6.8) */
+	int             root_port;
+	int             port_no;
+	root_port = No_port;
+	for (port_no = One; port_no <= No_of_ports; port_no++) {	/* (4.6.8.3.1) */
+		if (((!designated_port(port_no))
+		     &&
+		     (port_info[port_no].state != Disabled)
+		     &&
+		(br_cmp(port_info[port_no].designated_root.BRIDGE_ID,
+			bridge_info.bridge_id.BRIDGE_ID) < 0)
+			)
+				&&
+				((root_port == No_port)
+				 ||
+				 (br_cmp(port_info[port_no].designated_root.BRIDGE_ID,
+				  port_info[root_port].designated_root.BRIDGE_ID) < 0
+				  )
+				 ||
+				 ((br_cmp(port_info[port_no].designated_root.BRIDGE_ID,
+				   port_info[root_port].designated_root.BRIDGE_ID) == 0
+				   )
+				  &&
+				  (((port_info[port_no].designated_cost
+				     + port_info[port_no].path_cost
+				     )
+				    ==
+				    (port_info[root_port].designated_cost
+				     + port_info[root_port].path_cost
+				     )		  /* (4.6.8.3.1(2)) */
+				    )
+				   ||
+				   (((port_info[port_no].designated_cost
+				      + port_info[port_no].path_cost
+				      )
+				     ==
+				     (port_info[root_port].designated_cost
+				      + port_info[root_port].path_cost
+				      )
+				     )
+				    &&
+				    ((br_cmp(port_info[port_no].designated_bridge.BRIDGE_ID,
+				    port_info[root_port].designated_bridge.BRIDGE_ID) < 0
+				      )		  /* (4.6.8.3.1(3)) */
+				     ||
+				     ((br_cmp(port_info[port_no].designated_bridge.BRIDGE_ID,
+				   port_info[root_port].designated_bridge.BRIDGE_ID) == 0
+				       )
+				      &&
+				      ((port_info[port_no].designated_port
+				      < port_info[root_port].designated_port
+					)	  /* (4.6.8.3.1(4)) */
+				       ||
+				       ((port_info[port_no].designated_port
+				      = port_info[root_port].designated_port
+					 )
+					&&
+					(port_info[port_no].port_id
+					 < port_info[root_port].port_id
+					 )	  /* (4.6.8.3.1(5)) */
+					))))))))) {
+			root_port = port_no;
+		}
+	}
+	bridge_info.root_port = root_port;	  /* (4.6.8.3.1)	 */
+
+	if (root_port == No_port) {		  /* (4.6.8.3.2)	 */
+		bridge_info.designated_root = bridge_info.bridge_id;
+		/* (4.6.8.3.2(1)) */
+		bridge_info.root_path_cost = Zero;/* (4.6.8.3.2(2)) */
+	} else {				  /* (4.6.8.3.3)	 */
+		bridge_info.designated_root = port_info[root_port].designated_root;
+		/* (4.6.8.3.3(1)) */
+		bridge_info.root_path_cost = (port_info[root_port].designated_cost
+					    + port_info[root_port].path_cost
+			);			  /* (4.6.8.3.3(2)) */
+	}
+}
+
+void
+designated_port_selection(void)
+{						  /* (4.6.9)	 */
+	int             port_no;
+
+	for (port_no = One; port_no <= No_of_ports; port_no++) {	/* (4.6.9.3)	 */
+		if (designated_port(port_no)	  /* (4.6.9.3.1)	 */
+				||
+				(
+				 br_cmp(port_info[port_no].designated_root.BRIDGE_ID,
+				 bridge_info.designated_root.BRIDGE_ID) != 0
+				 )
+				||
+				(bridge_info.root_path_cost
+				 < port_info[port_no].designated_cost
+				 )		  /* (4.6.9.3.3)	 */
+				||
+				((bridge_info.root_path_cost
+				  == port_info[port_no].designated_cost
+				  )
+				 &&
+				 ((br_cmp(bridge_info.bridge_id.BRIDGE_ID,
+				   port_info[port_no].designated_bridge.BRIDGE_ID) < 0
+				   )		  /* (4.6.9.3.4)	 */
+				  ||
+				  ((br_cmp(bridge_info.bridge_id.BRIDGE_ID,
+				    port_info[port_no].designated_bridge.BRIDGE_ID) == 0
+				    )
+				   &&
+				   (port_info[port_no].port_id
+				    <= port_info[port_no].designated_port
+				    )		  /* (4.6.9.3.5)	 */
+				   )))) {
+			become_designated_port(port_no);	/* (4.6.10.3.2.2) */
+		}
+	}
+}
+
+void
+become_designated_port(int port_no)
+{						  /* (4.6.10)	 */
+
+	/* (4.6.10.3.1) */
+	port_info[port_no].designated_root = bridge_info.designated_root;
+	/* (4.6.10.3.2) */
+	port_info[port_no].designated_cost = bridge_info.root_path_cost;
+	/* (4.6.10.3.3) */
+	port_info[port_no].designated_bridge = bridge_info.bridge_id;
+	/* (4.6.10.3.4) */
+	port_info[port_no].designated_port = port_info[port_no].port_id;
+}
+
+void
+port_state_selection(void)
+{						  /* (4.6.11) */
+	int             port_no;
+	for (port_no = One; port_no <= No_of_ports; port_no++) {
+		if (port_no == bridge_info.root_port) {	/* (4.6.11.3.1) */
+			port_info[port_no].config_pending = FALSE;	/* (4.6.11.3~1(1)) */
+			port_info[port_no].top_change_ack = 0;
+			make_forwarding(port_no); /* (4.6.11.3.1(2)) */
+		} else if (designated_port(port_no)) {	/* (4.6.11.3.2) */
+			stop_message_age_timer(port_no);	/* (4.6.11.3.2(1)) */
+			make_forwarding(port_no); /* (4.6.11.3.2(2)) */
+		} else {			  /* (4.6.11.3.3) */
+			port_info[port_no].config_pending = FALSE;	/* (4.6.11.3.3(1)) */
+			port_info[port_no].top_change_ack = 0;
+			make_blocking(port_no);	  /* (4.6.11.3.3(2)) */
+		}
+	}
+
+}
+
+void
+make_forwarding(int port_no)
+{						  /* (4.6.12) */
+	if (port_info[port_no].state == Blocking) {	/* (4.6.12.3) */
+		set_port_state(port_no, Listening);	/* (4.6.12.3.1) */
+		start_forward_delay_timer(port_no);	/* (4.6.12.3.2) */
+	}
+}
+
+void 
+topology_change_detection(void)
+{						  /* (4.6.14)       */
+	if (root_bridge()) {			  /* (4.6.14.3.1)   */
+		bridge_info.top_change = 1;
+		start_topology_change_timer();	  /* (4.6.14.3.1(2)) */
+	} else if (!(bridge_info.top_change_detected)) {
+		transmit_tcn();			  /* (4.6.14.3.2(1)) */
+		start_tcn_timer();		  /* (4.6.14.3.2(2)) */
+	}
+	bridge_info.top_change = 1;
+}
+
+void
+topology_change_acknowledged(void)
+{						  /* (4.6.15) */
+	bridge_info.top_change_detected = 0;
+	stop_tcn_timer();			  /* (4.6.15.3.2) */
+}
+
+void
+acknowledge_topology_change(int port_no)
+{						  /* (4.6.16) */
+	port_info[port_no].top_change_ack = 1;
+	transmit_config(port_no);		  /* (4.6.16.3.2) */
+}
+
+void
+make_blocking(int port_no)				  /* (4.6.13)	 */
+{
+
+	if ((port_info[port_no].state != Disabled)
+			&&
+			(port_info[port_no].state != Blocking)
+	/* (4.6.13.3)	 */
+		) {
+		if ((port_info[port_no].state == Forwarding)
+				||
+				(port_info[port_no].state == Learning)
+			) {
+			topology_change_detection();	/* (4.6.13.3.1) */
+			/* (4.6.14.2.3)	 */
+		}
+		set_port_state(port_no, Blocking);/* (4.6.13.3.2) */
+		stop_forward_delay_timer(port_no);/* (4.6.13.3.3) */
+	}
+}
+
+void
+set_port_state(int port_no, int state)
+{
+	port_info[port_no].state = state;
+}
+
+void
+received_config_bpdu(int port_no, Config_bpdu *config)		  /* (4.7.1)	 */
+{
+	int         root;
+
+	root = root_bridge();
+	if (port_info[port_no].state != Disabled) {
+		if (supersedes_port_info(port_no, config)) {	/* (4.7.1.1)	 *//* (4.
+								 * 6.2.2)	 */
+			record_config_information(port_no, config);	/* (4.7.1.1.1)	 */
+			/* (4.6.2.2)	 */
+			configuration_update();	  /* (4.7.1.1.2)	 */
+			/* (4.6.7.2.1)	 */
+			port_state_selection();	  /* (4.7.1.1.3)	 */
+			/* (4.6.11.2.1)	 */
+			if ((!root_bridge()) && root) {	/* (4.7.1.1.4)	 */
+				stop_hello_timer();
+				if (bridge_info.top_change_detected) {	/* (4.7.1.1.5~ */
+					stop_topology_change_timer();
+					transmit_tcn();	/* (4.6.6.1)	 */
+					start_tcn_timer();
+				}
+			}
+			if (port_no == bridge_info.root_port) {
+				record_config_timeout_values(config);	/* (4.7.1.1.6)	 */
+				/* (4.6.3.2)	 */
+				config_bpdu_generation();	/* (4.6.4.2.1)	 */
+				if (config->flags & TOPOLOGY_CHANGE_ACK) {	/* (4.7.1.1.7)    */
+					topology_change_acknowledged();	/* (4.6.15.2)	 */
+				}
+			}
+		} else if (designated_port(port_no)) {	/* (4.7.1.2)	 */
+			reply(port_no);		  /* (4.7.1.2.1)	 */
+			/* (4.6.5.2)	 */
+		}
+	}
+}
+
+void
+received_tcn_bpdu(int port_no, Tcn_bpdu *tcn)			  /* (4.7.2)	 */
+{
+	if (port_info[port_no].state != Disabled) {
+		if (designated_port(port_no)) {
+			topology_change_detection();	/* (4.7.2.1)	 */
+			/* (4.6.14.2.1)	 */
+			acknowledge_topology_change(port_no);	/* (4.7.2.2)	 */
+		}				  /* (4.6.16.2)	 */
+	}
+}
+
+void
+hello_timer_expiry(void)
+{						  /* (4.7.3)	 */
+	config_bpdu_generation();		  /* (4.6.4.2.2)	 */
+	start_hello_timer();
+}
+
+void
+message_age_timer_expiry(int port_no)		  /* (4.7.4)	 */
+{
+	int         root;
+	root = root_bridge();
+
+	become_designated_port(port_no);	  /* (4.7.4.1)	 */
+	/* (4.6.10.2.1)	 */
+	configuration_update();			  /* (4.7.4.2)	 */
+	/* (4.6.7.2.2)	 */
+	port_state_selection();			  /* (4.7.4.3)	 */
+	/* (4.6.11.2.2)	 */
+	if ((root_bridge()) && (!root)) {	  /* (4.7.4.4)	 */
+
+		bridge_info.max_age = bridge_info.bridge_max_age;	/* (4.7.4.4.1)    */
+		bridge_info.hello_time = bridge_info.bridge_hello_time;
+		bridge_info.forward_delay = bridge_info.bridge_forward_delay;
+		topology_change_detection();	  /* (4.7.4.4.2)	 */
+		/* (4.6.14.2.4)	 */
+		stop_tcn_timer();		  /* (4.7.4.4.3)	 */
+		config_bpdu_generation();	  /* (4.7.4.4.4)	 */
+		/* (4.6.4.4.3)	 */
+		start_hello_timer();
+	}
+}
+
+void
+forward_delay_timer_expiry(int port_no)		  /* (4.7.5)	 */
+{
+	if (port_info[port_no].state == Listening) {	/* (4.7.5.1)	 */
+		set_port_state(port_no, Learning);	/* (4.7.5.1.1)	 */
+		start_forward_delay_timer(port_no);	/* (4.7.5.1.2)	 */
+	} else if (port_info[port_no].state == Learning) {	/* (4.7.5.2) */
+		set_port_state(port_no, Forwarding);	/* (4.7.5.2.1) */
+		if (designated_for_some_port()) { /* (4.7.5.2.2) */
+			topology_change_detection();	/* (4.6.14.2.2) */
+
+		}
+	}
+}
+
+int
+designated_for_some_port(void)
+{
+	int             port_no;
+
+
+	for (port_no = One; port_no <= No_of_ports; port_no++) {
+		if ((br_cmp(port_info[port_no].designated_bridge.BRIDGE_ID,
+				bridge_info.bridge_id.BRIDGE_ID) == 0)
+			) {
+			return (TRUE);
+		}
+	}
+	return (FALSE);
+}
+
+void
+tcn_timer_expiry(void)
+{						  /* (4.7.6)	 */
+	transmit_tcn();				  /* (4.7.6.1)	 */
+	start_tcn_timer();			  /* (4.7.6.2)	 */
+}
+
+void
+topology_change_timer_expiry(void)
+{						  /* (4.7.7)	 */
+	bridge_info.top_change_detected = 0;
+	bridge_info.top_change = 0;
+	  /* (4.7.7.2)	 */
+}
+
+void
+hold_timer_expiry(int port_no)			  /* (4.7.8)	 */
+{
+	if (port_info[port_no].config_pending) {
+		transmit_config(port_no);	  /* (4.7.8.1)	 */
+	}					  /* (4.6.1.2.3)	 */
+}
+
+void
+br_init(void)
+{						  /* (4.8.1)	 */
+	int             port_no;
+
+	bridge_info.designated_root = bridge_info.bridge_id;	/* (4.8.1.1)	 */
+	bridge_info.root_path_cost = Zero;
+	bridge_info.root_port = No_port;
+
+	bridge_info.bridge_max_age = BRIDGE_MAX_AGE;
+	bridge_info.bridge_hello_time = BRIDGE_HELLO_TIME;
+	bridge_info.bridge_forward_delay = BRIDGE_FORWARD_DELAY;
+	bridge_info.hold_time = HOLD_TIME;
+
+	bridge_info.max_age = bridge_info.bridge_max_age;	/* (4.8.1.2)	 */
+	bridge_info.hello_time = bridge_info.bridge_hello_time;
+	bridge_info.forward_delay = bridge_info.bridge_forward_delay;
+
+	bridge_info.top_change_detected = 0;
+	bridge_info.top_change = 0;
+	stop_tcn_timer();
+	stop_topology_change_timer();
+	for (port_no = One; port_no <= No_of_ports; port_no++) {	/* (4.8.1.4) */
+		br_init_port(port_no);
+		disable_port(port_no);
+	}
+	port_state_selection();			  /* (4.8.1.5)	 */
+	config_bpdu_generation();		  /* (4.8.1.6)	 */
+	
+	/* initialize system timer */
+	tl.expires = HZ;	/* 1 second */
+	tl.function = br_tick;
+	add_timer(&tl);
+
+	register_netdevice_notifier(&br_dev_notifier);
+	br_stats.flags = BR_UP | BR_DEBUG;	/* enable bridge */
+	start_hello_timer();
+}
+
+void
+br_init_port(int port_no)
+{
+	become_designated_port(port_no);	  /* (4.8.1.4.1) */
+	set_port_state(port_no, Blocking);	  /* (4.8.1.4.2)    */
+	port_info[port_no].top_change_ack = 0;
+	port_info[port_no].config_pending = FALSE;/* (4.8.1.4.4)	 */
+	stop_message_age_timer(port_no);	  /* (4.8.1.4.5)	 */
+	stop_forward_delay_timer(port_no);	  /* (4.8.1.4.6)	 */
+	stop_hold_timer(port_no);		  /* (4.8.1.4.7)	 */
+}
+
+void
+enable_port(int port_no)				  /* (4.8.2)	 */
+{
+	br_init_port(port_no);
+	port_state_selection();			  /* (4.8.2.7)	 */
+}						  /* */
+
+void
+disable_port(int port_no)				  /* (4.8.3)	 */
+{
+	int         root;
+
+	root = root_bridge();
+	become_designated_port(port_no);	  /* (4.8.3.1)	 */
+	set_port_state(port_no, Disabled);	  /* (4.8.3.2)	 */
+	port_info[port_no].top_change_ack = 0;
+	port_info[port_no].config_pending = FALSE;/* (4.8.3.4)	 */
+	stop_message_age_timer(port_no);	  /* (4.8.3.5)	 */
+	stop_forward_delay_timer(port_no);	  /* (4.8.3.6)	 */
+	configuration_update();
+	port_state_selection();			  /* (4.8.3.7)	 */
+	if ((root_bridge()) && (!root)) {	  /* (4.8.3.8)	 */
+		bridge_info.max_age = bridge_info.bridge_max_age;	/* (4.8.3.8.1)    */
+		bridge_info.hello_time = bridge_info.bridge_hello_time;
+		bridge_info.forward_delay = bridge_info.bridge_forward_delay;
+		topology_change_detection();	  /* (4.8.3.8.2)    */
+		stop_tcn_timer();		  /* (4.8.3.8.3)    */
+		config_bpdu_generation();	  /* (4.8.3.8.4)    */
+		start_hello_timer();
+	}
+}
+
+
+void
+set_bridge_priority(bridge_id_t *new_bridge_id)		  /* (4.8.4)	 */
+{
+
+	int         root;
+	int             port_no;
+	root = root_bridge();
+	for (port_no = One; port_no <= No_of_ports; port_no++) {	/* (4.8.4.2) */
+		if (designated_port(port_no)) {
+			port_info[port_no].designated_bridge = *new_bridge_id;
+		}
+	}
+
+	bridge_info.bridge_id = *new_bridge_id;	  /* (4.8.4.3)	 */
+	configuration_update();			  /* (4.8.4.4)	 */
+	port_state_selection();			  /* (4.8.4.5)	 */
+	if ((root_bridge()) && (!root)) {	  /* (4.8.4.6)	 */
+		bridge_info.max_age = bridge_info.bridge_max_age;	/* (4.8.4.6.1)    */
+		bridge_info.hello_time = bridge_info.bridge_hello_time;
+		bridge_info.forward_delay = bridge_info.bridge_forward_delay;
+		topology_change_detection();	  /* (4.8.4.6.2)    */
+		stop_tcn_timer();		  /* (4.8.4.6.3)    */
+		config_bpdu_generation(),	  /* (4.8.4.6.4)    */
+		start_hello_timer();
+	}
+}
+
+void
+set_port_priority(int port_no, unsigned short new_port_id)		  /* (4.8.5)	 */
+{
+	if (designated_port(port_no)) {		  /* (4.8.5.2)	 */
+		port_info[port_no].designated_port = new_port_id;
+	}
+	port_info[port_no].port_id = new_port_id; /* (4.8.5.3)	 */
+	if ((br_cmp(bridge_info.bridge_id.BRIDGE_ID,
+	     port_info[port_no].designated_bridge.BRIDGE_ID) == 0
+	     )
+			&&
+			(port_info[port_no].port_id
+			 < port_info[port_no].designated_port
+
+			 )
+		) {
+		become_designated_port(port_no);  /* (4.8.5.4.1) */
+		port_state_selection();		  /* (4.8.5.4.2) */
+	}
+}
+
+void
+set_path_cost(int port_no, unsigned short path_cost)		  /* (4.8.6)	 */
+{
+	port_info[port_no].path_cost = path_cost; /* (4.8.6.1)	 */
+	configuration_update();			  /* (4.8.6.2)	 */
+	port_state_selection();			  /* (4.8.6.3)	 */
+}
+
+static void
+br_tick(unsigned long arg)
+{
+	int             port_no;
+
+	if (hello_timer_expired()) {
+		hello_timer_expiry();
+	}
+	if (tcn_timer_expired()) {
+		tcn_timer_expiry();
+	}
+	if (topology_change_timer_expired()) {
+		topology_change_timer_expiry();
+	}
+	for (port_no = One; port_no <= No_of_ports; port_no++) {
+		if (forward_delay_timer_expired(port_no)) {
+			forward_delay_timer_expiry(port_no);
+		}
+		if (message_age_timer_expired(port_no)) {
+			message_age_timer_expiry(port_no);
+		}
+		if (hold_timer_expired(port_no)) {
+			hold_timer_expiry(port_no);
+		}
+	}
+	/* call me again sometime... */
+	tl.expires = HZ;	/* 1 second */
+	tl.function = br_tick;
+	add_timer(&tl);
+}
+
+void
+start_hello_timer(void)
+{
+	hello_timer.value = 0;
+	hello_timer.active = TRUE;
+}
+
+void
+stop_hello_timer(void)
+{
+	hello_timer.active = FALSE;
+}
+
+int
+hello_timer_expired(void)
+{
+	if (hello_timer.active && (++hello_timer.value >= bridge_info.hello_time)) {
+		hello_timer.active = FALSE;
+		return (TRUE);
+	}
+	return (FALSE);
+}
+
+void
+start_tcn_timer(void)
+{
+	tcn_timer.value = 0;
+	tcn_timer.active = TRUE;
+}
+
+void
+stop_tcn_timer(void)
+{
+	tcn_timer.active = FALSE;
+}
+
+int
+tcn_timer_expired(void)
+{
+	if (tcn_timer.active && (++tcn_timer.value >=
+				 bridge_info.bridge_hello_time)) {
+		tcn_timer.active = FALSE;
+		return (TRUE);
+	}
+	return (FALSE);
+
+}
+
+void
+start_topology_change_timer(void)
+{
+	topology_change_timer.value = 0;
+	topology_change_timer.active = TRUE;
+}
+
+void
+stop_topology_change_timer(void)
+{
+	topology_change_timer.active = FALSE;
+}
+
+int
+topology_change_timer_expired(void)
+{
+	if (topology_change_timer.active
+			&& (++topology_change_timer.value
+			    >= bridge_info.topology_change_time
+			    )) {
+		topology_change_timer.active = FALSE;
+		return (TRUE);
+	}
+	return (FALSE);
+}
+
+void
+start_message_age_timer(int port_no, unsigned short message_age)
+{
+	message_age_timer[port_no].value = message_age;
+	message_age_timer[port_no].active = TRUE;
+}
+
+void
+stop_message_age_timer(int port_no)
+{
+	message_age_timer[port_no].active = FALSE;
+}
+
+int
+message_age_timer_expired(int port_no)
+{
+	if (message_age_timer[port_no].active &&
+	      (++message_age_timer[port_no].value >= bridge_info.max_age)) {
+		message_age_timer[port_no].active = FALSE;
+		return (TRUE);
+	}
+	return (FALSE);
+}
+
+void
+start_forward_delay_timer(int port_no)
+{
+	forward_delay_timer[port_no].value = 0;
+	forward_delay_timer[port_no].active = TRUE;
+}
+
+void
+stop_forward_delay_timer(int port_no)
+{
+	forward_delay_timer[port_no].active = FALSE;
+}
+
+int
+forward_delay_timer_expired(int port_no)
+{
+		if (forward_delay_timer[port_no].active &&
+				(++forward_delay_timer[port_no].value >= bridge_info.forward_delay)) {
+			forward_delay_timer[port_no].active = FALSE;
+			return (TRUE);
+		}
+		return (FALSE);
+}
+
+void
+start_hold_timer(int port_no)
+{
+	hold_timer[port_no].value = 0;
+	hold_timer[port_no].active = TRUE;
+}
+
+void
+stop_hold_timer(int port_no)
+{
+	hold_timer[port_no].active = FALSE;
+}
+
+
+int
+hold_timer_expired(int port_no)
+{
+	if (hold_timer[port_no].active &&
+		   (++hold_timer[port_no].value >= bridge_info.hold_time)) {
+		hold_timer[port_no].active = FALSE;
+		return (TRUE);
+	}
+	return (FALSE);
+
+}
+
+int
+send_config_bpdu(int port_no, Config_bpdu *config_bpdu)
+{
+struct sk_buff *skb;
+struct device *dev = port_info[port_no].dev;
+int size;
+unsigned long flags;
+	
+	if (port_info[port_no].state == Disabled) {
+		printk("send_config_bpdu: port %i not valid\n",port_no);
+		return(-1);
+		}
+	if (br_stats.flags & BR_DEBUG)
+		printk("send_config_bpdu: ");
+	/*
+	 * create and send the message
+	 */
+	size = sizeof(Config_bpdu) + dev->hard_header_len;
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (skb == NULL) {
+		printk("send_config_bpdu: no skb available\n");
+		return(-1);
+		}
+	skb->dev = dev;
+	skb->free = 1;
+	skb->h.eth = (struct ethhdr *)skb_put(skb, size);
+	memcpy(skb->h.eth->h_dest, bridge_ula, ETH_ALEN);
+	memcpy(skb->h.eth->h_source, dev->dev_addr, ETH_ALEN);
+	if (br_stats.flags & BR_DEBUG)
+		printk("port %i src %02x:%02x:%02x:%02x:%02x:%02x\
+			dest %02x:%02x:%02x:%02x:%02x:%02x\n", 
+			port_no,
+			skb->h.eth->h_source[0],
+			skb->h.eth->h_source[1],
+			skb->h.eth->h_source[2],
+			skb->h.eth->h_source[3],
+			skb->h.eth->h_source[4],
+			skb->h.eth->h_source[5],
+			skb->h.eth->h_dest[0],
+			skb->h.eth->h_dest[1],
+			skb->h.eth->h_dest[2],
+			skb->h.eth->h_dest[3],
+			skb->h.eth->h_dest[4],
+			skb->h.eth->h_dest[5]);
+	skb->h.eth->h_proto = htonl(0x8038);	/* XXX verify */
+
+	skb->h.raw += skb->dev->hard_header_len;
+	memcpy(skb->h.raw, config_bpdu, sizeof(Config_bpdu));
+
+	/* won't get bridged again... */
+	skb->pkt_bridged = IS_BRIDGED;
+	skb->arp = 1;	/* do not resolve... */
+	skb->h.raw = skb->data + ETH_HLEN;
+	save_flags(flags);
+	cli();
+	skb_queue_tail(dev->buffs, skb);
+	restore_flags(flags);
+	return(0);
+}
+
+int
+send_tcn_bpdu(int port_no, Tcn_bpdu *bpdu)
+{
+struct sk_buff *skb;
+struct device *dev = port_info[port_no].dev;
+int size;
+unsigned long flags;
+	
+	if (port_info[port_no].state == Disabled) {
+		printk("send_tcn_bpdu: port %i not valid\n",port_no);
+		return(-1);
+		}
+	if (br_stats.flags & BR_DEBUG)
+		printk("send_tcn_bpdu: ");
+	size = sizeof(Tcn_bpdu) + dev->hard_header_len;
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (skb == NULL) {
+		printk("send_tcn_bpdu: no skb available\n");
+		return(-1);
+		}
+	skb->dev = dev;
+	skb->free = 1;
+	skb->h.eth = (struct ethhdr *)skb_put(skb,size);
+	memcpy(skb->h.eth->h_dest, bridge_ula, ETH_ALEN);
+	memcpy(skb->h.eth->h_source, dev->dev_addr, ETH_ALEN);
+	if (br_stats.flags & BR_DEBUG)
+		printk("port %i src %02x:%02x:%02x:%02x:%02x:%02x\
+			dest %02x:%02x:%02x:%02x:%02x:%02x\n", 
+			port_no,
+			skb->h.eth->h_source[0],
+			skb->h.eth->h_source[1],
+			skb->h.eth->h_source[2],
+			skb->h.eth->h_source[3],
+			skb->h.eth->h_source[4],
+			skb->h.eth->h_source[5],
+			skb->h.eth->h_dest[0],
+			skb->h.eth->h_dest[1],
+			skb->h.eth->h_dest[2],
+			skb->h.eth->h_dest[3],
+			skb->h.eth->h_dest[4],
+			skb->h.eth->h_dest[5]);
+	skb->h.eth->h_proto = 0x8038;	/* XXX verify */
+
+	skb->h.raw += skb->dev->hard_header_len;
+	memcpy(skb->h.raw, bpdu, sizeof(Tcn_bpdu));
+
+	/* mark that's we've been here... */
+	skb->pkt_bridged = IS_BRIDGED;
+	skb->arp = 1;	/* do not resolve... */
+	skb->h.raw = skb->data + ETH_HLEN;
+	save_flags(flags);
+	cli();
+	skb_queue_tail(dev->buffs, skb);
+	restore_flags(flags);
+	return(0);
+}
+
+static int 
+br_device_event(struct notifier_block *unused, unsigned long event, void *ptr)
+{
+	struct device *dev = ptr;
+	int i;
+
+	/* check for loopback devices */
+	if (dev->flags & IFF_LOOPBACK)
+		return(NOTIFY_DONE);
+
+	switch (event) {
+	case NETDEV_DOWN:
+		if (br_stats.flags & BR_DEBUG)
+			printk("br_device_event: NETDEV_DOWN...\n");
+		/* find our device and mark it down */
+		for (i = One; i <= No_of_ports; i++) {
+			if (port_info[i].dev == dev) {
+				disable_port(i);
+				return NOTIFY_DONE;
+				break;
+			}
+		}
+		break;
+	case NETDEV_UP:
+		if (br_stats.flags & BR_DEBUG)
+			printk("br_device_event: NETDEV_UP...\n");
+		/* Only handle ethernet ports */
+		if(dev->type!=ARPHRD_ETHER && dev->type!=ARPHRD_LOOPBACK)
+			return NOTIFY_DONE;
+		/* look up an unused device and enable it */
+		for (i = One; i <= No_of_ports; i++) {
+			if ((port_info[i].dev == (struct device *)0) ||
+				(port_info[i].dev == dev)) {
+				port_info[i].dev = dev;
+				enable_port(i);
+				set_path_cost(i, br_port_cost(dev));
+				set_port_priority(i, 128); 
+				port_info[i].port_id = i;
+				/* set bridge addr from 1st device addr */
+				if ((bridge_info.bridge_id.BRIDGE_ID[0] == 0) &&
+						(bridge_info.bridge_id.BRIDGE_ID[1] == 0)) {
+					memcpy(bridge_info.bridge_id.BRIDGE_ID_ULA, dev->dev_addr, 6);
+					bridge_info.bridge_id.BRIDGE_PRIORITY = port_info[i].port_id;
+					set_bridge_priority(&bridge_info.bridge_id);
+				}	
+				make_forwarding(i);
+				return NOTIFY_DONE;
+				break;
+			}
+		}
+		break;
+	default:
+		printk("br_device_event: unknown event [%x]\n",
+			(unsigned int)event);
+	}
+	return NOTIFY_DONE;
+}
+
+/*
+ * following routine is called when a frame is received
+ * from an interface, it returns 1 when it consumes the
+ * frame, 0 when it does not
+ */
+
+int
+br_receive_frame(struct sk_buff *skb)	/* 3.5 */
+{
+	int port;
+	
+	if (br_stats.flags & BR_DEBUG)
+		printk("br_receive_frame: ");
+	/* sanity */
+	if (!skb) {
+		printk("no skb!\n");
+		return(1);
+	}
+	/* check for loopback */
+	if (skb->dev->flags & IFF_LOOPBACK)
+		return(0);
+
+	port = find_port(skb->dev);
+	skb->h.raw = skb->data;
+	if (br_stats.flags & BR_DEBUG)
+		printk("port %i src %02x:%02x:%02x:%02x:%02x:%02x\
+			dest %02x:%02x:%02x:%02x:%02x:%02x\n", 
+			port,
+			skb->h.eth->h_source[0],
+			skb->h.eth->h_source[1],
+			skb->h.eth->h_source[2],
+			skb->h.eth->h_source[3],
+			skb->h.eth->h_source[4],
+			skb->h.eth->h_source[5],
+			skb->h.eth->h_dest[0],
+			skb->h.eth->h_dest[1],
+			skb->h.eth->h_dest[2],
+			skb->h.eth->h_dest[3],
+			skb->h.eth->h_dest[4],
+			skb->h.eth->h_dest[5]);
+
+	if (!port) {
+		printk("\nbr_receive_frame: no port!\n");
+		return(0);
+	}
+
+	switch (port_info[port].state) {
+		case Learning:
+			(void) br_learn(skb, port);	/* 3.8 */
+			/* fall through */
+		case Listening:
+			/* process BPDUs */
+			if (memcmp(skb->h.eth->h_dest, bridge_ula, 6) == 0) {
+				br_bpdu(skb);
+				return(1); /* br_bpdu consumes skb */
+			}
+			/* fall through */
+		case Blocking:
+			/* fall through */
+		case Disabled:
+			/* should drop frames, but for now, we let
+			 * them get passed up to the next higher layer
+			return(br_drop(skb));	
+			 */
+			return(0);	/* pass frame up stack */
+			break;
+		case Forwarding:
+			(void) br_learn(skb, port);	/* 3.8 */
+			/* process BPDUs */
+			if (memcmp(skb->h.eth->h_dest, bridge_ula, 
+					ETH_ALEN) == 0) {
+				printk("frame bpdu processor for me!!!\n");
+				br_bpdu(skb);
+				return(1); /* br_bpdu consumes skb */
+			}
+			/* is frame for me? */	
+			if (memcmp(skb->h.eth->h_dest, 
+					port_info[port].dev->dev_addr, 
+					ETH_ALEN) == 0) {
+				return(0);	/* pass frame up our stack (this will */
+						/* happen in net_bh() in dev.c) */
+			}
+			/* ok, forward this frame... */
+			return(br_forward(skb, port));
+		default:
+			printk("br_receive_frame: port [%i] unknown state [%i]\n",
+				port, port_info[port].state);
+			return(0);	/* pass frame up stack? */
+	}
+}
+
+/*
+ * the following routine is called to transmit frames from the host
+ * stack.  it returns 1 when it consumes the frame and
+ * 0 when it does not.
+ */
+
+int
+br_tx_frame(struct sk_buff *skb)	/* 3.5 */
+{
+	int port;
+	
+	/* sanity */
+	if (!skb) {
+		printk("br_tx_frame: no skb!\n");
+		return(0);
+	}
+	/* check for loopback */
+	if (skb->dev->flags & IFF_LOOPBACK)
+		return(0);
+
+	skb->h.raw = skb->data;
+	port = 0;	/* an impossible port */	
+	if (br_stats.flags & BR_DEBUG)
+		printk("br_tx_fr : port %i src %02x:%02x:%02x:%02x:%02x:%02x\
+	  		dest %02x:%02x:%02x:%02x:%02x:%02x\n", 
+			port,
+			skb->h.eth->h_source[0],
+			skb->h.eth->h_source[1],
+			skb->h.eth->h_source[2],
+			skb->h.eth->h_source[3],
+			skb->h.eth->h_source[4],
+			skb->h.eth->h_source[5],
+			skb->h.eth->h_dest[0],
+			skb->h.eth->h_dest[1],
+			skb->h.eth->h_dest[2],
+			skb->h.eth->h_dest[3],
+			skb->h.eth->h_dest[4],
+			skb->h.eth->h_dest[5]);
+	return(br_forward(skb, port));
+}
+
+/*
+ * this routine returns 0 when it learns (or updates) from the
+ * frame, and -1 if the frame is simply discarded due to port
+ * state or lack of resources...
+ */
+
+int
+br_learn(struct sk_buff *skb, int port)	/* 3.8 */
+{
+	struct fdb *f;
+
+	switch (port_info[port].state) {
+		case Listening:
+		case Blocking:
+		case Disabled:
+		default:
+			return(-1);
+			/* break; */
+		case Learning:
+		case Forwarding:
+			/* don't keep group addresses in the tree */
+			if (skb->h.eth->h_source[0] & 0x01)
+				return(-1);
+			
+			f = (struct fdb *)kmalloc(sizeof(struct fdb), 
+				GFP_ATOMIC);
+
+			if (!f) {
+				printk("br_learn: unable to malloc fdb\n");
+				return(-1);
+			}
+			f->port = port;	/* source port */
+			memcpy(f->ula, skb->h.eth->h_source, 6);
+			f->timer = CURRENT_TIME;
+			f->flags = FDB_ENT_VALID;
+			/*
+			 * add entity to AVL tree.  If entity already
+			 * exists in the tree, update the fields with
+			 * what we have here.
+		  	 */
+			if (br_avl_insert(f) == 0) { /* update */
+				kfree(f);
+				return(0);
+			}
+			/* add to head of port chain */
+			f->fdb_next = port_info[port].fdb;
+			port_info[port].fdb = f;
+			return(0);
+			/* break */
+	}
+}
+
+/*
+ * this routine always consumes the frame
+ */
+
+int
+br_drop(struct sk_buff *skb)
+{
+	kfree_skb(skb, 0);
+	return(1);
+}
+
+/*
+ * this routine returns 1 if it consumes the frame, 0
+ * if not...
+ */
+
+int
+br_forward(struct sk_buff *skb, int port)	/* 3.7 */
+{
+struct fdb *f;
+unsigned long flags;
+	
+	/*
+   	 * flood all ports with frames destined for a group
+	 * address.  If frame came from above, drop it,
+	 * otherwise it will be handled in br_receive_frame()
+	 * Multicast frames will also need to be seen
+	 * by our upper layers.
+	 */	
+	if (skb->h.eth->h_dest[0] & 0x01) {	/* group address */
+		br_flood(skb, port);
+		if (port == 0) 			/* locally generated */
+			return(br_drop(skb));
+		return(0);
+	} else {
+		/* locate port to forward to */
+		f = br_avl_find_addr(skb->h.eth->h_dest);
+		if (!f | !(f->flags & FDB_ENT_VALID)) {
+		 	/* not found; flood all ports */
+			br_flood(skb, port);
+			return(br_drop(skb));
+		}
+		if (port_info[f->port].state == Forwarding) {
+			/* has entry expired? */
+			if (f->timer + fdb_aging_time < CURRENT_TIME) {
+				/* timer expired, invalidate entry */
+				f->flags &= ~FDB_ENT_VALID;
+				if (br_stats.flags & BR_DEBUG)
+					printk("fdb entry expired...\n");
+				br_flood(skb, port);
+				return(br_drop(skb));
+			}
+			/* mark that's we've been here... */
+			skb->pkt_bridged = IS_BRIDGED;
+			
+			/*
+			 * if the frame is originating in this host,
+			 * we may need to resolve the outgoing address
+			if (port != 0)
+				skb->arp = 1;
+			 */
+		
+			/* reset the skb->ip pointer */	
+			skb->h.raw = skb->data + ETH_HLEN;
+
+			/* we must unlock the skb before requeueing it... */
+			if (skb_device_locked(skb))
+				skb_device_unlock(skb);
+
+			save_flags(flags);	/* enter critical section */
+			cli();
+			skb_queue_head(port_info[f->port].dev->buffs, skb);
+			restore_flags(flags);	/* exit critical section */
+			return(1);	/* skb has been consumed */
+		} else {
+			return(br_drop(skb));
+		}
+	}
+}
+
+/*
+ * this routine sends a copy of the frame to all forwarding ports
+ * with the exception of the port given.  This routine never
+ * consumes the original frame.
+ */
+	
+int
+br_flood(struct sk_buff *skb, int port)
+{
+int i;
+struct sk_buff *nskb;
+unsigned long flags;
+
+	for (i = One; i <= No_of_ports; i++) {
+		if (i == port)
+			continue;
+		if (port_info[i].state == Forwarding) {
+			nskb = skb_clone(skb, GFP_ATOMIC);
+			/* mark that's we've been here... */
+			nskb->pkt_bridged = IS_BRIDGED;
+			/*
+			 * if the frame is originating in this host,
+			 * we may need to resolve the outgoing address
+			if (port != 0)
+				nskb->arp = 1;
+			 */
+			nskb->h.raw = nskb->data + ETH_HLEN;
+			save_flags(flags);
+			cli();
+			skb_queue_tail(port_info[i].dev->buffs, nskb);
+			restore_flags(flags);
+		}
+	}
+	return(0);
+}
+
+int
+find_port(struct device *dev)
+{
+int i;
+
+	for (i = One; i <= No_of_ports; i++)
+		if ((port_info[i].dev == dev) && 
+			(port_info[i].state != Disabled))
+			return(i);
+	return(0);
+}
+
+int
+br_port_cost(struct device *dev)	/* 4.10.2 */
+{
+	if (strncmp(dev->name, "eth", 3) == 0)	/* ethernet */
+		return(100);
+	if (strncmp(dev->name, "wic", 3) == 0)	/* wic */
+		return(1600);
+	if (strncmp(dev->name, "plip",4) == 0) /* plip */
+		return (1600);
+	return(100);	/* default */
+}
+
+/*
+ * this routine always consumes the skb 
+ */
+
+void
+br_bpdu(struct sk_buff *skb) /* consumes skb */
+{
+Tcn_bpdu *bpdu;
+int port;
+
+	port = find_port(skb->dev);
+	if (port == 0) {	/* unknown port */
+		br_drop(skb);
+		return;
+	}
+		
+	bpdu = (Tcn_bpdu *)skb->data + ETH_HLEN;
+	switch (bpdu->type) {
+		case BPDU_TYPE_CONFIG:
+			received_config_bpdu(port, (Config_bpdu *)bpdu);
+			break;
+		case BPDU_TYPE_TOPO_CHANGE:
+			received_tcn_bpdu(port, bpdu);
+			break;
+		default:
+			printk("br_bpdu: received unknown bpdu, type = %i\n",
+				bpdu->type);
+			/* break; */
+	}
+	br_drop(skb);
+}
+
+int
+br_ioctl(unsigned int cmd, void *arg)
+{
+	int err;
+	struct br_cf bcf;
+	int i;
+
+	switch(cmd)
+	{
+		case SIOCGIFBR:	/* get bridging control blocks */
+			err = verify_area(VERIFY_WRITE, arg, 
+				sizeof(struct br_stat));
+			if(err)
+				return err;
+			memcpy(&br_stats.bridge_data, &bridge_info, sizeof(Bridge_data));
+			memcpy(&br_stats.port_data, &port_info, sizeof(Port_data)*No_of_ports);
+			memcpy_tofs(arg, &br_stats, sizeof(struct br_stat));
+			return(0);
+		case SIOCSIFBR:
+			if (!suser())
+				return -EPERM;
+			err = verify_area(VERIFY_READ, arg, 
+				sizeof(struct br_cf));
+			if(err)
+				return err;
+			memcpy_fromfs(&bcf, arg, sizeof(struct br_cf));
+			switch (bcf.cmd) {
+				case BRCMD_BRIDGE_ENABLE:
+					if (br_stats.flags & BR_UP)
+						return(-EALREADY);	
+					printk("br: enabling bridging function\n");
+					register_netdevice_notifier(&br_dev_notifier);
+					br_stats.flags |= BR_UP;	/* enable bridge */
+					start_hello_timer();
+					break;
+				case BRCMD_BRIDGE_DISABLE:
+					if (!(br_stats.flags & BR_UP))
+						return(-EALREADY);	
+					printk("br: disabling bridging function\n");
+					unregister_netdevice_notifier(&br_dev_notifier);
+					br_stats.flags &= ~BR_UP;	/* disable bridge */
+					stop_hello_timer();
+					for (i = One; i <= No_of_ports; i++)
+						if (port_info[i].state != Disabled)
+							disable_port(i);
+					break;
+				case BRCMD_PORT_ENABLE:
+					if (port_info[bcf.arg1].dev == 0)
+						return(-EINVAL);
+					if (port_info[bcf.arg1].state != Disabled)
+						return(-EALREADY);
+					printk("br: enabling port %i\n",bcf.arg1);
+					enable_port(bcf.arg1);
+					break;
+				case BRCMD_PORT_DISABLE:
+					if (port_info[bcf.arg1].dev == 0)
+						return(-EINVAL);
+					if (port_info[bcf.arg1].state == Disabled)
+						return(-EALREADY);
+					printk("br: disabling port %i\n",bcf.arg1);
+					disable_port(bcf.arg1);
+					break;
+				case BRCMD_SET_BRIDGE_PRIORITY:
+					set_bridge_priority((bridge_id_t *)&bcf.arg1);
+					break;
+				case BRCMD_SET_PORT_PRIORITY:
+					if (port_info[bcf.arg1].dev == 0)
+						return(-EINVAL);
+					set_port_priority(bcf.arg1, bcf.arg2);
+					break;
+				case BRCMD_SET_PATH_COST:
+					if (port_info[bcf.arg1].dev == 0)
+						return(-EINVAL);
+					set_path_cost(bcf.arg1, bcf.arg2);
+					break;
+				case BRCMD_ENABLE_DEBUG:
+					br_stats.flags |= BR_DEBUG;
+					break;
+				case BRCMD_DISABLE_DEBUG:
+					br_stats.flags &= ~BR_DEBUG;
+					break;
+				default:
+					return -EINVAL;
+			}
+			return(0);
+		default:
+			return -EINVAL;
+	}
+	/*NOTREACHED*/
+	return 0;
+}
+
+int br_cmp(unsigned int *a, unsigned int *b)
+{
+	int i;	
+	for (i=0; i<2; i++) {
+		if (a[i] == b[i])
+			continue;
+		if (a[i] < b[i])
+			return(1);
+		if (a[i] > b[i])
+			return(-1);
+	}
+	return(0);
+}
+		

FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov with Sam's (original) version
of this