net/bridge/br_stp_if.c

   1 /*
   2  *      Spanning tree protocol; interface code
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      $Id: br_stp_if.c,v 1.4 2001/04/14 21:14:39 davem Exp $
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/etherdevice.h>
  19
  20 #include "br_private.h"
  21 #include "br_private_stp.h"
  22
  23
  24 /* Port id is composed of priority and port number.
  25  * NB: least significant bits of priority are dropped to
  26  *     make room for more ports.
  27  */
  28 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
  29 {
  30         return ((u16)priority << BR_PORT_BITS)
  31                 | (port_no & ((1<<BR_PORT_BITS)-1));
  32 }
  33
  34 /* called under bridge lock */
  35 void br_init_port(struct net_bridge_port *p)
  36 {
  37         p->port_id = br_make_port_id(p->priority, p->port_no);
  38         br_become_designated_port(p);
  39         p->state = BR_STATE_BLOCKING;
  40         p->topology_change_ack = 0;
  41         p->config_pending = 0;
  42
  43         br_stp_port_timer_init(p);
  44 }
  45
  46 /* called under bridge lock */
  47 void br_stp_enable_bridge(struct net_bridge *br)
  48 {
  49         struct net_bridge_port *p;
  50
  51         spin_lock_bh(&br->lock);
  52         mod_timer(&br->hello_timer, jiffies + br->hello_time);
  53         mod_timer(&br->gc_timer, jiffies + HZ/10);
  54
  55         br_config_bpdu_generation(br);
  56
  57         list_for_each_entry(p, &br->port_list, list) {
  58                 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
  59                         br_stp_enable_port(p);
  60
  61         }
  62         spin_unlock_bh(&br->lock);
  63 }
  64
  65 /* NO locks held */
  66 void br_stp_disable_bridge(struct net_bridge *br)
  67 {
  68         struct net_bridge_port *p;
  69
  70         spin_lock(&br->lock);
  71         list_for_each_entry(p, &br->port_list, list) {
  72                 if (p->state != BR_STATE_DISABLED)
  73                         br_stp_disable_port(p);
  74
  75         }
  76
  77         br->topology_change = 0;
  78         br->topology_change_detected = 0;
  79         spin_unlock(&br->lock);
  80
  81         del_timer_sync(&br->hello_timer);
  82         del_timer_sync(&br->topology_change_timer);
  83         del_timer_sync(&br->tcn_timer);
  84         del_timer_sync(&br->gc_timer);
  85 }
  86
  87 /* called under bridge lock */
  88 void br_stp_enable_port(struct net_bridge_port *p)
  89 {
  90         br_init_port(p);
  91         br_port_state_selection(p->br);
  92 }
  93
  94 /* called under bridge lock */
  95 void br_stp_disable_port(struct net_bridge_port *p)
  96 {
  97         struct net_bridge *br;
  98         int wasroot;
  99
 100         br = p->br;
 101         printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
 102                br->dev->name, p->port_no, p->dev->name, "disabled");
 103
 104         wasroot = br_is_root_bridge(br);
 105         br_become_designated_port(p);
 106         p->state = BR_STATE_DISABLED;
 107         p->topology_change_ack = 0;
 108         p->config_pending = 0;
 109
 110         del_timer(&p->message_age_timer);
 111         del_timer(&p->forward_delay_timer);
 112         del_timer(&p->hold_timer);
 113
 114         br_configuration_update(br);
 115
 116         br_port_state_selection(br);
 117
 118         if (br_is_root_bridge(br) && !wasroot)
 119                 br_become_root_bridge(br);
 120 }
 121
 122 /* called under bridge lock */
 123 static void br_stp_change_bridge_id(struct net_bridge *br,
 124                                     const unsigned char *addr)
 125 {
 126         unsigned char oldaddr[6];
 127         struct net_bridge_port *p;
 128         int wasroot;
 129
 130         wasroot = br_is_root_bridge(br);
 131
 132         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 133         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 134         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 135
 136         list_for_each_entry(p, &br->port_list, list) {
 137                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 138                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 139
 140                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 141                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 142
 143         }
 144
 145         br_configuration_update(br);
 146         br_port_state_selection(br);
 147         if (br_is_root_bridge(br) && !wasroot)
 148                 br_become_root_bridge(br);
 149 }
 150
 151 static const unsigned char br_mac_zero[6];
 152
 153 /* called under bridge lock */
 154 void br_stp_recalculate_bridge_id(struct net_bridge *br)
 155 {
 156         const unsigned char *addr = br_mac_zero;
 157         struct net_bridge_port *p;
 158
 159         list_for_each_entry(p, &br->port_list, list) {
 160                 if (addr == br_mac_zero ||
 161                     compare_ether_addr(p->dev->dev_addr, addr) < 0)
 162                         addr = p->dev->dev_addr;
 163
 164         }
 165
 166         if (compare_ether_addr(br->bridge_id.addr, addr))
 167                 br_stp_change_bridge_id(br, addr);
 168 }
 169
 170 /* called under bridge lock */
 171 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 172 {
 173         struct net_bridge_port *p;
 174         int wasroot;
 175
 176         wasroot = br_is_root_bridge(br);
 177
 178         list_for_each_entry(p, &br->port_list, list) {
 179                 if (p->state != BR_STATE_DISABLED &&
 180                     br_is_designated_port(p)) {
 181                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 182                         p->designated_bridge.prio[1] = newprio & 0xFF;
 183                 }
 184
 185         }
 186
 187         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 188         br->bridge_id.prio[1] = newprio & 0xFF;
 189         br_configuration_update(br);
 190         br_port_state_selection(br);
 191         if (br_is_root_bridge(br) && !wasroot)
 192                 br_become_root_bridge(br);
 193 }
 194
 195 /* called under bridge lock */
 196 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
 197 {
 198         port_id new_port_id = br_make_port_id(newprio, p->port_no);
 199
 200         if (br_is_designated_port(p))
 201                 p->designated_port = new_port_id;
 202
 203         p->port_id = new_port_id;
 204         p->priority = newprio;
 205         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 206             p->port_id < p->designated_port) {
 207                 br_become_designated_port(p);
 208                 br_port_state_selection(p->br);
 209         }
 210 }
 211
 212 /* called under bridge lock */
 213 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
 214 {
 215         p->path_cost = path_cost;
 216         br_configuration_update(p->br);
 217         br_port_state_selection(p->br);
 218 }
 219
 220 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 221 {
 222         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 223                id->prio[0], id->prio[1],
 224                id->addr[0], id->addr[1], id->addr[2],
 225                id->addr[3], id->addr[4], id->addr[5]);
 226 }