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