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/etherdevice.h>
  18 #include <linux/rtnetlink.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_fdb_delete_by_port(br, p, 0);
 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 static void br_stp_start(struct net_bridge *br)
 123 {
 124         int r;
 125         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
 126         char *envp[] = { NULL };
 127
 128         r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 129         if (r == 0) {
 130                 br->stp_enabled = BR_USER_STP;
 131                 printk(KERN_INFO "%s: userspace STP started\n", br->dev->name);
 132         } else {
 133                 br->stp_enabled = BR_KERNEL_STP;
 134                 printk(KERN_INFO "%s: starting userspace STP failed, "
 135                                 "starting kernel STP\n", br->dev->name);
 136
 137                 /* To start timers on any ports left in blocking */
 138                 spin_lock_bh(&br->lock);
 139                 br_port_state_selection(br);
 140                 spin_unlock_bh(&br->lock);
 141         }
 142 }
 143
 144 static void br_stp_stop(struct net_bridge *br)
 145 {
 146         int r;
 147         char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
 148         char *envp[] = { NULL };
 149
 150         if (br->stp_enabled == BR_USER_STP) {
 151                 r = call_usermodehelper(BR_STP_PROG, argv, envp, 1);
 152                 printk(KERN_INFO "%s: userspace STP stopped, return code %d\n",
 153                         br->dev->name, r);
 154
 155
 156                 /* To start timers on any ports left in blocking */
 157                 spin_lock_bh(&br->lock);
 158                 br_port_state_selection(br);
 159                 spin_unlock_bh(&br->lock);
 160         }
 161
 162         br->stp_enabled = BR_NO_STP;
 163 }
 164
 165 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 166 {
 167         ASSERT_RTNL();
 168
 169         if (val) {
 170                 if (br->stp_enabled == BR_NO_STP)
 171                         br_stp_start(br);
 172         } else {
 173                 if (br->stp_enabled != BR_NO_STP)
 174                         br_stp_stop(br);
 175         }
 176 }
 177
 178 /* called under bridge lock */
 179 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 180 {
 181         /* should be aligned on 2 bytes for compare_ether_addr() */
 182         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 183         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 184         struct net_bridge_port *p;
 185         int wasroot;
 186
 187         wasroot = br_is_root_bridge(br);
 188
 189         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 190         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 191         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 192
 193         list_for_each_entry(p, &br->port_list, list) {
 194                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 195                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 196
 197                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 198                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 199
 200         }
 201
 202         br_configuration_update(br);
 203         br_port_state_selection(br);
 204         if (br_is_root_bridge(br) && !wasroot)
 205                 br_become_root_bridge(br);
 206 }
 207
 208 /* should be aligned on 2 bytes for compare_ether_addr() */
 209 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 210
 211 /* called under bridge lock */
 212 void br_stp_recalculate_bridge_id(struct net_bridge *br)
 213 {
 214         const unsigned char *br_mac_zero =
 215                         (const unsigned char *)br_mac_zero_aligned;
 216         const unsigned char *addr = br_mac_zero;
 217         struct net_bridge_port *p;
 218
 219         list_for_each_entry(p, &br->port_list, list) {
 220                 if (addr == br_mac_zero ||
 221                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 222                         addr = p->dev->dev_addr;
 223
 224         }
 225
 226         if (compare_ether_addr(br->bridge_id.addr, addr))
 227                 br_stp_change_bridge_id(br, addr);
 228 }
 229
 230 /* called under bridge lock */
 231 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 232 {
 233         struct net_bridge_port *p;
 234         int wasroot;
 235
 236         wasroot = br_is_root_bridge(br);
 237
 238         list_for_each_entry(p, &br->port_list, list) {
 239                 if (p->state != BR_STATE_DISABLED &&
 240                     br_is_designated_port(p)) {
 241                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 242                         p->designated_bridge.prio[1] = newprio & 0xFF;
 243                 }
 244
 245         }
 246
 247         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 248         br->bridge_id.prio[1] = newprio & 0xFF;
 249         br_configuration_update(br);
 250         br_port_state_selection(br);
 251         if (br_is_root_bridge(br) && !wasroot)
 252                 br_become_root_bridge(br);
 253 }
 254
 255 /* called under bridge lock */
 256 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
 257 {
 258         port_id new_port_id = br_make_port_id(newprio, p->port_no);
 259
 260         if (br_is_designated_port(p))
 261                 p->designated_port = new_port_id;
 262
 263         p->port_id = new_port_id;
 264         p->priority = newprio;
 265         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 266             p->port_id < p->designated_port) {
 267                 br_become_designated_port(p);
 268                 br_port_state_selection(p->br);
 269         }
 270 }
 271
 272 /* called under bridge lock */
 273 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
 274 {
 275         p->path_cost = path_cost;
 276         br_configuration_update(p->br);
 277         br_port_state_selection(p->br);
 278 }
 279
 280 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 281 {
 282         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 283                id->prio[0], id->prio[1],
 284                id->addr[0], id->addr[1], id->addr[2],
 285                id->addr[3], id->addr[4], id->addr[5]);
 286 }