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