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 #include <linux/rtnetlink.h>
  20
  21 #include "br_private.h"
  22 #include "br_private_stp.h"
  23
  24
  25 /* Port id is composed of priority and port number.
  26  * NB: least significant bits of priority are dropped to
  27  *     make room for more ports.
  28  */
  29 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
  30 {
  31         return ((u16)priority << BR_PORT_BITS)
  32                 | (port_no & ((1<<BR_PORT_BITS)-1));
  33 }
  34
  35 /* called under bridge lock */
  36 void br_init_port(struct net_bridge_port *p)
  37 {
  38         p->port_id = br_make_port_id(p->priority, p->port_no);
  39         br_become_designated_port(p);
  40         p->state = BR_STATE_BLOCKING;
  41         p->topology_change_ack = 0;
  42         p->config_pending = 0;
  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_bh(&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_bh(&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_ifinfo_notify(RTM_NEWLINK, 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         br_ifinfo_notify(RTM_DELLINK, p);
 105
 106         wasroot = br_is_root_bridge(br);
 107         br_become_designated_port(p);
 108         p->state = BR_STATE_DISABLED;
 109         p->topology_change_ack = 0;
 110         p->config_pending = 0;
 111
 112         del_timer(&p->message_age_timer);
 113         del_timer(&p->forward_delay_timer);
 114         del_timer(&p->hold_timer);
 115
 116         br_fdb_delete_by_port(br, p, 0);
 117
 118         br_configuration_update(br);
 119
 120         br_port_state_selection(br);
 121
 122         if (br_is_root_bridge(br) && !wasroot)
 123                 br_become_root_bridge(br);
 124 }
 125
 126 /* called under bridge lock */
 127 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 128 {
 129         /* should be aligned on 2 bytes for compare_ether_addr() */
 130         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 131         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 132         struct net_bridge_port *p;
 133         int wasroot;
 134
 135         wasroot = br_is_root_bridge(br);
 136
 137         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 138         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 139         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 140
 141         list_for_each_entry(p, &br->port_list, list) {
 142                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 143                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 144
 145                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 146                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 147
 148         }
 149
 150         br_configuration_update(br);
 151         br_port_state_selection(br);
 152         if (br_is_root_bridge(br) && !wasroot)
 153                 br_become_root_bridge(br);
 154 }
 155
 156 /* should be aligned on 2 bytes for compare_ether_addr() */
 157 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 158
 159 /* called under bridge lock */
 160 void br_stp_recalculate_bridge_id(struct net_bridge *br)
 161 {
 162         const unsigned char *br_mac_zero =
 163                         (const unsigned char *)br_mac_zero_aligned;
 164         const unsigned char *addr = br_mac_zero;
 165         struct net_bridge_port *p;
 166
 167         list_for_each_entry(p, &br->port_list, list) {
 168                 if (addr == br_mac_zero ||
 169                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 170                         addr = p->dev->dev_addr;
 171
 172         }
 173
 174         if (compare_ether_addr(br->bridge_id.addr, addr))
 175                 br_stp_change_bridge_id(br, addr);
 176 }
 177
 178 /* called under bridge lock */
 179 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 180 {
 181         struct net_bridge_port *p;
 182         int wasroot;
 183
 184         wasroot = br_is_root_bridge(br);
 185
 186         list_for_each_entry(p, &br->port_list, list) {
 187                 if (p->state != BR_STATE_DISABLED &&
 188                     br_is_designated_port(p)) {
 189                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 190                         p->designated_bridge.prio[1] = newprio & 0xFF;
 191                 }
 192
 193         }
 194
 195         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 196         br->bridge_id.prio[1] = newprio & 0xFF;
 197         br_configuration_update(br);
 198         br_port_state_selection(br);
 199         if (br_is_root_bridge(br) && !wasroot)
 200                 br_become_root_bridge(br);
 201 }
 202
 203 /* called under bridge lock */
 204 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
 205 {
 206         port_id new_port_id = br_make_port_id(newprio, p->port_no);
 207
 208         if (br_is_designated_port(p))
 209                 p->designated_port = new_port_id;
 210
 211         p->port_id = new_port_id;
 212         p->priority = newprio;
 213         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 214             p->port_id < p->designated_port) {
 215                 br_become_designated_port(p);
 216                 br_port_state_selection(p->br);
 217         }
 218 }
 219
 220 /* called under bridge lock */
 221 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
 222 {
 223         p->path_cost = path_cost;
 224         br_configuration_update(p->br);
 225         br_port_state_selection(p->br);
 226 }
 227
 228 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 229 {
 230         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 231                id->prio[0], id->prio[1],
 232                id->addr[0], id->addr[1], id->addr[2],
 233                id->addr[3], id->addr[4], id->addr[5]);
 234 }