1 files changed, 459 insertions, 0 deletions

diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
new file mode 100644
index 000000000000..04ca0639a95a
--- /dev/null
+++ b/net/bridge/br_stp.c
@@ -0,0 +1,459 @@
+/*
+ *      Spanning tree protocol; generic parts
+ *      Linux ethernet bridge
+ *
+ *      Authors:
+ *      Lennert Buytenhek               <buytenh@gnu.org>
+ *
+ *      $Id: br_stp.c,v 1.4 2000/06/19 10:13:35 davem Exp $
+ *
+ *      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.
+ */
+#include <linux/kernel.h>
+#include <linux/smp_lock.h>
+
+#include "br_private.h"
+#include "br_private_stp.h"
+
+/* since time values in bpdu are in jiffies and then scaled (1/256)
+ * before sending, make sure that is at least one.
+ */
+#define MESSAGE_AGE_INCR        ((HZ < 256) ? 1 : (HZ/256))
+
+static const char *br_port_state_names[] = {
+        [BR_STATE_DISABLED] = "disabled", 
+        [BR_STATE_LISTENING] = "listening",
+        [BR_STATE_LEARNING] = "learning", 
+        [BR_STATE_FORWARDING] = "forwarding", 
+        [BR_STATE_BLOCKING] = "blocking",
+};
+
+void br_log_state(const struct net_bridge_port *p)
+{
+        pr_info("%s: port %d(%s) entering %s state\n",
+                p->br->dev->name, p->port_no, p->dev->name, 
+                br_port_state_names[p->state]);
+
+}
+
+/* called under bridge lock */
+struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
+{
+        struct net_bridge_port *p;
+
+        list_for_each_entry_rcu(p, &br->port_list, list) {
+                if (p->port_no == port_no)
+                        return p;
+        }
+
+        return NULL;
+}
+
+/* called under bridge lock */
+static int br_should_become_root_port(const struct net_bridge_port *p, 
+                                      u16 root_port)
+{
+        struct net_bridge *br;
+        struct net_bridge_port *rp;
+        int t;
+
+        br = p->br;
+        if (p->state == BR_STATE_DISABLED ||
+            br_is_designated_port(p))
+                return 0;
+
+        if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
+                return 0;
+
+        if (!root_port)
+                return 1;
+
+        rp = br_get_port(br, root_port);
+
+        t = memcmp(&p->designated_root, &rp->designated_root, 8);
+        if (t < 0)
+                return 1;
+        else if (t > 0)
+                return 0;
+
+        if (p->designated_cost + p->path_cost <
+            rp->designated_cost + rp->path_cost)
+                return 1;
+        else if (p->designated_cost + p->path_cost >
+                 rp->designated_cost + rp->path_cost)
+                return 0;
+
+        t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
+        if (t < 0)
+                return 1;
+        else if (t > 0)
+                return 0;
+
+        if (p->designated_port < rp->designated_port)
+                return 1;
+        else if (p->designated_port > rp->designated_port)
+                return 0;
+
+        if (p->port_id < rp->port_id)
+                return 1;
+
+        return 0;
+}
+
+/* called under bridge lock */
+static void br_root_selection(struct net_bridge *br)
+{
+        struct net_bridge_port *p;
+        u16 root_port = 0;
+
+        list_for_each_entry(p, &br->port_list, list) {
+                if (br_should_become_root_port(p, root_port))
+                        root_port = p->port_no;
+
+        }
+
+        br->root_port = root_port;
+
+        if (!root_port) {
+                br->designated_root = br->bridge_id;
+                br->root_path_cost = 0;
+        } else {
+                p = br_get_port(br, root_port);
+                br->designated_root = p->designated_root;
+                br->root_path_cost = p->designated_cost + p->path_cost;
+        }
+}
+
+/* called under bridge lock */
+void br_become_root_bridge(struct net_bridge *br)
+{
+        br->max_age = br->bridge_max_age;
+        br->hello_time = br->bridge_hello_time;
+        br->forward_delay = br->bridge_forward_delay;
+        br_topology_change_detection(br);
+        del_timer(&br->tcn_timer);
+
+        if (br->dev->flags & IFF_UP) {
+                br_config_bpdu_generation(br);
+                mod_timer(&br->hello_timer, jiffies + br->hello_time);
+        }
+}
+
+/* called under bridge lock */
+void br_transmit_config(struct net_bridge_port *p)
+{
+        struct br_config_bpdu bpdu;
+        struct net_bridge *br;
+
+
+        if (timer_pending(&p->hold_timer)) {
+                p->config_pending = 1;
+                return;
+        }
+
+        br = p->br;
+
+        bpdu.topology_change = br->topology_change;
+        bpdu.topology_change_ack = p->topology_change_ack;
+        bpdu.root = br->designated_root;
+        bpdu.root_path_cost = br->root_path_cost;
+        bpdu.bridge_id = br->bridge_id;
+        bpdu.port_id = p->port_id;
+        if (br_is_root_bridge(br))
+                bpdu.message_age = 0;
+        else {
+                struct net_bridge_port *root
+                        = br_get_port(br, br->root_port);
+                bpdu.message_age = br->max_age
+                        - (root->message_age_timer.expires - jiffies)
+                        + MESSAGE_AGE_INCR;
+        }
+        bpdu.max_age = br->max_age;
+        bpdu.hello_time = br->hello_time;
+        bpdu.forward_delay = br->forward_delay;
+
+        if (bpdu.message_age < br->max_age) {
+                br_send_config_bpdu(p, &bpdu);
+                p->topology_change_ack = 0;
+                p->config_pending = 0;
+                mod_timer(&p->hold_timer, jiffies + BR_HOLD_TIME);
+        }
+}
+
+/* called under bridge lock */
+static inline void br_record_config_information(struct net_bridge_port *p, 
+                                                const struct br_config_bpdu *bpdu)
+{
+        p->designated_root = bpdu->root;
+        p->designated_cost = bpdu->root_path_cost;
+        p->designated_bridge = bpdu->bridge_id;
+        p->designated_port = bpdu->port_id;
+
+        mod_timer(&p->message_age_timer, jiffies 
+                  + (p->br->max_age - bpdu->message_age));
+}
+
+/* called under bridge lock */
+static inline void br_record_config_timeout_values(struct net_bridge *br, 
+                                            const struct br_config_bpdu *bpdu)
+{
+        br->max_age = bpdu->max_age;
+        br->hello_time = bpdu->hello_time;
+        br->forward_delay = bpdu->forward_delay;
+        br->topology_change = bpdu->topology_change;
+}
+
+/* called under bridge lock */
+void br_transmit_tcn(struct net_bridge *br)
+{
+        br_send_tcn_bpdu(br_get_port(br, br->root_port));
+}
+
+/* called under bridge lock */
+static int br_should_become_designated_port(const struct net_bridge_port *p)
+{
+        struct net_bridge *br;
+        int t;
+
+        br = p->br;
+        if (br_is_designated_port(p))
+                return 1;
+
+        if (memcmp(&p->designated_root, &br->designated_root, 8))
+                return 1;
+
+        if (br->root_path_cost < p->designated_cost)
+                return 1;
+        else if (br->root_path_cost > p->designated_cost)
+                return 0;
+
+        t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
+        if (t < 0)
+                return 1;
+        else if (t > 0)
+                return 0;
+
+        if (p->port_id < p->designated_port)
+                return 1;
+
+        return 0;
+}
+
+/* called under bridge lock */
+static void br_designated_port_selection(struct net_bridge *br)
+{
+        struct net_bridge_port *p;
+
+        list_for_each_entry(p, &br->port_list, list) {
+                if (p->state != BR_STATE_DISABLED &&
+                    br_should_become_designated_port(p))
+                        br_become_designated_port(p);
+
+        }
+}
+
+/* called under bridge lock */
+static int br_supersedes_port_info(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
+{
+        int t;
+
+        t = memcmp(&bpdu->root, &p->designated_root, 8);
+        if (t < 0)
+                return 1;
+        else if (t > 0)
+                return 0;
+
+        if (bpdu->root_path_cost < p->designated_cost)
+                return 1;
+        else if (bpdu->root_path_cost > p->designated_cost)
+                return 0;
+
+        t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
+        if (t < 0)
+                return 1;
+        else if (t > 0)
+                return 0;
+
+        if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
+                return 1;
+
+        if (bpdu->port_id <= p->designated_port)
+                return 1;
+
+        return 0;
+}
+
+/* called under bridge lock */
+static inline void br_topology_change_acknowledged(struct net_bridge *br)
+{
+        br->topology_change_detected = 0;
+        del_timer(&br->tcn_timer);
+}
+
+/* called under bridge lock */
+void br_topology_change_detection(struct net_bridge *br)
+{
+        int isroot = br_is_root_bridge(br);
+
+        pr_info("%s: topology change detected, %s\n", br->dev->name,
+                isroot ? "propagating" : "sending tcn bpdu");
+
+        if (isroot) {
+                br->topology_change = 1;
+                mod_timer(&br->topology_change_timer, jiffies
+                          + br->bridge_forward_delay + br->bridge_max_age);
+        } else if (!br->topology_change_detected) {
+                br_transmit_tcn(br);
+                mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
+        }
+
+        br->topology_change_detected = 1;
+}
+
+/* called under bridge lock */
+void br_config_bpdu_generation(struct net_bridge *br)
+{
+        struct net_bridge_port *p;
+
+        list_for_each_entry(p, &br->port_list, list) {
+                if (p->state != BR_STATE_DISABLED &&
+                    br_is_designated_port(p))
+                        br_transmit_config(p);
+        }
+}
+
+/* called under bridge lock */
+static inline void br_reply(struct net_bridge_port *p)
+{
+        br_transmit_config(p);
+}
+
+/* called under bridge lock */
+void br_configuration_update(struct net_bridge *br)
+{
+        br_root_selection(br);
+        br_designated_port_selection(br);
+}
+
+/* called under bridge lock */
+void br_become_designated_port(struct net_bridge_port *p)
+{
+        struct net_bridge *br;
+
+        br = p->br;
+        p->designated_root = br->designated_root;
+        p->designated_cost = br->root_path_cost;
+        p->designated_bridge = br->bridge_id;
+        p->designated_port = p->port_id;
+}
+
+
+/* called under bridge lock */
+static void br_make_blocking(struct net_bridge_port *p)
+{
+        if (p->state != BR_STATE_DISABLED &&
+            p->state != BR_STATE_BLOCKING) {
+                if (p->state == BR_STATE_FORWARDING ||
+                    p->state == BR_STATE_LEARNING)
+                        br_topology_change_detection(p->br);
+
+                p->state = BR_STATE_BLOCKING;
+                br_log_state(p);
+                del_timer(&p->forward_delay_timer);
+        }
+}
+
+/* called under bridge lock */
+static void br_make_forwarding(struct net_bridge_port *p)
+{
+        if (p->state == BR_STATE_BLOCKING) {
+                if (p->br->stp_enabled) {
+                        p->state = BR_STATE_LISTENING;
+                } else {
+                        p->state = BR_STATE_LEARNING;
+                }
+                br_log_state(p);
+                mod_timer(&p->forward_delay_timer, jiffies + p->br->forward_delay);     }
+}
+
+/* called under bridge lock */
+void br_port_state_selection(struct net_bridge *br)
+{
+        struct net_bridge_port *p;
+
+        list_for_each_entry(p, &br->port_list, list) {
+                if (p->state != BR_STATE_DISABLED) {
+                        if (p->port_no == br->root_port) {
+                                p->config_pending = 0;
+                                p->topology_change_ack = 0;
+                                br_make_forwarding(p);
+                        } else if (br_is_designated_port(p)) {
+                                del_timer(&p->message_age_timer);
+                                br_make_forwarding(p);
+                        } else {
+                                p->config_pending = 0;
+                                p->topology_change_ack = 0;
+                                br_make_blocking(p);
+                        }
+                }
+
+        }
+}
+
+/* called under bridge lock */
+static inline void br_topology_change_acknowledge(struct net_bridge_port *p)
+{
+        p->topology_change_ack = 1;
+        br_transmit_config(p);
+}
+
+/* called under bridge lock */
+void br_received_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
+{
+        struct net_bridge *br;
+        int was_root;
+ 
+        br = p->br;
+        was_root = br_is_root_bridge(br);
+
+        if (br_supersedes_port_info(p, bpdu)) {
+                br_record_config_information(p, bpdu);
+                br_configuration_update(br);
+                br_port_state_selection(br);
+
+                if (!br_is_root_bridge(br) && was_root) {
+                        del_timer(&br->hello_timer);
+                        if (br->topology_change_detected) {
+                                del_timer(&br->topology_change_timer);
+                                br_transmit_tcn(br);
+
+                                mod_timer(&br->tcn_timer, 
+                                          jiffies + br->bridge_hello_time);
+                        }
+                }
+
+                if (p->port_no == br->root_port) {
+                        br_record_config_timeout_values(br, bpdu);
+                        br_config_bpdu_generation(br);
+                        if (bpdu->topology_change_ack)
+                                br_topology_change_acknowledged(br);
+                }
+        } else if (br_is_designated_port(p)) {          
+                br_reply(p);            
+        }
+}
+
+/* called under bridge lock */
+void br_received_tcn_bpdu(struct net_bridge_port *p)
+{
+        if (br_is_designated_port(p)) {
+                pr_info("%s: received tcn bpdu on port %i(%s)\n",
+                       p->br->dev->name, p->port_no, p->dev->name);
+
+                br_topology_change_detection(p->br);
+                br_topology_change_acknowledge(p);
+        }
+}