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
  44 /* called under bridge lock */
  45 void br_stp_enable_bridge(struct net_bridge *br)
  46 {
  47         struct net_bridge_port *p;
  48
  49         spin_lock_bh(&br->lock);
  50         mod_timer(&br->hello_timer, jiffies + br->hello_time);
  51         mod_timer(&br->gc_timer, jiffies + HZ/10);
  52
  53         br_config_bpdu_generation(br);
  54
  55         list_for_each_entry(p, &br->port_list, list) {
  56                 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
  57                         br_stp_enable_port(p);
  58
  59         }
  60         spin_unlock_bh(&br->lock);
  61 }
  62
  63 /* NO locks held */
  64 void br_stp_disable_bridge(struct net_bridge *br)
  65 {
  66         struct net_bridge_port *p;
  67
  68         spin_lock_bh(&br->lock);
  69         list_for_each_entry(p, &br->port_list, list) {
  70                 if (p->state != BR_STATE_DISABLED)
  71                         br_stp_disable_port(p);
  72
  73         }
  74
  75         br->topology_change = 0;
  76         br->topology_change_detected = 0;
  77         spin_unlock_bh(&br->lock);
  78
  79         del_timer_sync(&br->hello_timer);
  80         del_timer_sync(&br->topology_change_timer);
  81         del_timer_sync(&br->tcn_timer);
  82         del_timer_sync(&br->gc_timer);
  83 }
  84
  85 /* called under bridge lock */
  86 void br_stp_enable_port(struct net_bridge_port *p)
  87 {
  88         br_init_port(p);
  89         br_port_state_selection(p->br);
  90 }
  91
  92 /* called under bridge lock */
  93 void br_stp_disable_port(struct net_bridge_port *p)
  94 {
  95         struct net_bridge *br;
  96         int wasroot;
  97
  98         br = p->br;
  99         printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
 100                br->dev->name, p->port_no, p->dev->name, "disabled");
 101
 102         wasroot = br_is_root_bridge(br);
 103         br_become_designated_port(p);
 104         p->state = BR_STATE_DISABLED;
 105         p->topology_change_ack = 0;
 106         p->config_pending = 0;
 107
 108         del_timer(&p->message_age_timer);
 109         del_timer(&p->forward_delay_timer);
 110         del_timer(&p->hold_timer);
 111
 112         br_configuration_update(br);
 113
 114         br_port_state_selection(br);
 115
 116         if (br_is_root_bridge(br) && !wasroot)
 117                 br_become_root_bridge(br);
 118 }
 119
 120 /* called under bridge lock */
 121 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 122 {
 123         unsigned char oldaddr[6];
 124         struct net_bridge_port *p;
 125         int wasroot;
 126
 127         wasroot = br_is_root_bridge(br);
 128
 129         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 130         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 131         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 132
 133         list_for_each_entry(p, &br->port_list, list) {
 134                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 135                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 136
 137                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 138                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 139
 140         }
 141
 142         br_configuration_update(br);
 143         br_port_state_selection(br);
 144         if (br_is_root_bridge(br) && !wasroot)
 145                 br_become_root_bridge(br);
 146 }
 147
 148 static const unsigned char br_mac_zero[6];
 149
 150 /* called under bridge lock */
 151 void br_stp_recalculate_bridge_id(struct net_bridge *br)
 152 {
 153         const unsigned char *addr = br_mac_zero;
 154         struct net_bridge_port *p;
 155
 156         list_for_each_entry(p, &br->port_list, list) {
 157                 if (addr == br_mac_zero ||
 158                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 159                         addr = p->dev->dev_addr;
 160
 161         }
 162
 163         if (compare_ether_addr(br->bridge_id.addr, addr))
 164                 br_stp_change_bridge_id(br, addr);
 165 }
 166
 167 /* called under bridge lock */
 168 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 169 {
 170         struct net_bridge_port *p;
 171         int wasroot;
 172
 173         wasroot = br_is_root_bridge(br);
 174
 175         list_for_each_entry(p, &br->port_list, list) {
 176                 if (p->state != BR_STATE_DISABLED &&
 177                     br_is_designated_port(p)) {
 178                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 179                         p->designated_bridge.prio[1] = newprio & 0xFF;
 180                 }
 181
 182         }
 183
 184         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 185         br->bridge_id.prio[1] = newprio & 0xFF;
 186         br_configuration_update(br);
 187         br_port_state_selection(br);
 188         if (br_is_root_bridge(br) && !wasroot)
 189                 br_become_root_bridge(br);
 190 }
 191
 192 /* called under bridge lock */
 193 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
 194 {
 195         port_id new_port_id = br_make_port_id(newprio, p->port_no);
 196
 197         if (br_is_designated_port(p))
 198                 p->designated_port = new_port_id;
 199
 200         p->port_id = new_port_id;
 201         p->priority = newprio;
 202         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 203             p->port_id < p->designated_port) {
 204                 br_become_designated_port(p);
 205                 br_port_state_selection(p->br);
 206         }
 207 }
 208
 209 /* called under bridge lock */
 210 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
 211 {
 212         p->path_cost = path_cost;
 213         br_configuration_update(p->br);
 214         br_port_state_selection(p->br);
 215 }
 216
 217 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 218 {
 219         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 220                id->prio[0], id->prio[1],
 221                id->addr[0], id->addr[1], id->addr[2],
 222                id->addr[3], id->addr[4], id->addr[5]);
 223 }