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  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/kmod.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/rtnetlink.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: some 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 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
  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         br_set_state(p, 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         if (br->stp_enabled == BR_KERNEL_STP)
  52                 mod_timer(&br->hello_timer, jiffies + br->hello_time);
  53         mod_timer(&br->gc_timer, jiffies + HZ/10);
  54
  55         br_config_bpdu_generation(br);
  56
  57         list_for_each_entry(p, &br->port_list, list) {
  58                 if (netif_running(p->dev) && netif_oper_up(p->dev))
  59                         br_stp_enable_port(p);
  60
  61         }
  62         spin_unlock_bh(&br->lock);
  63 }
  64
  65 /* NO locks held */
  66 void br_stp_disable_bridge(struct net_bridge *br)
  67 {
  68         struct net_bridge_port *p;
  69
  70         spin_lock_bh(&br->lock);
  71         list_for_each_entry(p, &br->port_list, list) {
  72                 if (p->state != BR_STATE_DISABLED)
  73                         br_stp_disable_port(p);
  74
  75         }
  76
  77         br->topology_change = 0;
  78         br->topology_change_detected = 0;
  79         spin_unlock_bh(&br->lock);
  80
  81         del_timer_sync(&br->hello_timer);
  82         del_timer_sync(&br->topology_change_timer);
  83         del_timer_sync(&br->tcn_timer);
  84         del_timer_sync(&br->gc_timer);
  85 }
  86
  87 /* called under bridge lock */
  88 void br_stp_enable_port(struct net_bridge_port *p)
  89 {
  90         br_init_port(p);
  91         br_port_state_selection(p->br);
  92         br_log_state(p);
  93         br_ifinfo_notify(RTM_NEWLINK, p);
  94 }
  95
  96 /* called under bridge lock */
  97 void br_stp_disable_port(struct net_bridge_port *p)
  98 {
  99         struct net_bridge *br = p->br;
 100         int wasroot;
 101
 102         wasroot = br_is_root_bridge(br);
 103         br_become_designated_port(p);
 104         br_set_state(p, BR_STATE_DISABLED);
 105         p->topology_change_ack = 0;
 106         p->config_pending = 0;
 107
 108         br_log_state(p);
 109         br_ifinfo_notify(RTM_NEWLINK, p);
 110
 111         del_timer(&p->message_age_timer);
 112         del_timer(&p->forward_delay_timer);
 113         del_timer(&p->hold_timer);
 114
 115         br_fdb_delete_by_port(br, p, 0, 0);
 116         br_multicast_disable_port(p);
 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 static void br_stp_start(struct net_bridge *br)
 127 {
 128         int r;
 129         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
 130         char *envp[] = { NULL };
 131         struct net_bridge_port *p;
 132
 133         r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 134
 135         spin_lock_bh(&br->lock);
 136
 137         if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
 138                 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
 139         else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
 140                 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
 141
 142         if (r == 0) {
 143                 br->stp_enabled = BR_USER_STP;
 144                 br_debug(br, "userspace STP started\n");
 145                 /* Stop hello and hold timers */
 146                 del_timer(&br->hello_timer);
 147                 list_for_each_entry(p, &br->port_list, list)
 148                         del_timer(&p->hold_timer);
 149         } else {
 150                 br->stp_enabled = BR_KERNEL_STP;
 151                 br_debug(br, "using kernel STP\n");
 152
 153                 /* To start timers on any ports left in blocking */
 154                 br_port_state_selection(br);
 155         }
 156
 157         spin_unlock_bh(&br->lock);
 158 }
 159
 160 static void br_stp_stop(struct net_bridge *br)
 161 {
 162         int r;
 163         char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
 164         char *envp[] = { NULL };
 165         struct net_bridge_port *p;
 166
 167         if (br->stp_enabled == BR_USER_STP) {
 168                 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 169                 br_info(br, "userspace STP stopped, return code %d\n", r);
 170
 171                 /* To start timers on any ports left in blocking */
 172                 mod_timer(&br->hello_timer, jiffies + br->hello_time);
 173                 list_for_each_entry(p, &br->port_list, list)
 174                         mod_timer(&p->hold_timer,
 175                                   round_jiffies(jiffies + BR_HOLD_TIME));
 176                 spin_lock_bh(&br->lock);
 177                 br_port_state_selection(br);
 178                 spin_unlock_bh(&br->lock);
 179         }
 180
 181         br->stp_enabled = BR_NO_STP;
 182 }
 183
 184 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 185 {
 186         ASSERT_RTNL();
 187
 188         if (val) {
 189                 if (br->stp_enabled == BR_NO_STP)
 190                         br_stp_start(br);
 191         } else {
 192                 if (br->stp_enabled != BR_NO_STP)
 193                         br_stp_stop(br);
 194         }
 195 }
 196
 197 /* called under bridge lock */
 198 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 199 {
 200         /* should be aligned on 2 bytes for ether_addr_equal() */
 201         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 202         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 203         struct net_bridge_port *p;
 204         int wasroot;
 205
 206         wasroot = br_is_root_bridge(br);
 207
 208         br_fdb_change_mac_address(br, addr);
 209
 210         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 211         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 212         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 213
 214         list_for_each_entry(p, &br->port_list, list) {
 215                 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
 216                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 217
 218                 if (ether_addr_equal(p->designated_root.addr, oldaddr))
 219                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 220         }
 221
 222         br_configuration_update(br);
 223         br_port_state_selection(br);
 224         if (br_is_root_bridge(br) && !wasroot)
 225                 br_become_root_bridge(br);
 226 }
 227
 228 /* should be aligned on 2 bytes for ether_addr_equal() */
 229 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 230
 231 /* called under bridge lock */
 232 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
 233 {
 234         const unsigned char *br_mac_zero =
 235                         (const unsigned char *)br_mac_zero_aligned;
 236         const unsigned char *addr = br_mac_zero;
 237         struct net_bridge_port *p;
 238
 239         /* user has chosen a value so keep it */
 240         if (br->dev->addr_assign_type == NET_ADDR_SET)
 241                 return false;
 242
 243         list_for_each_entry(p, &br->port_list, list) {
 244                 if (addr == br_mac_zero ||
 245                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 246                         addr = p->dev->dev_addr;
 247
 248         }
 249
 250         if (ether_addr_equal(br->bridge_id.addr, addr))
 251                 return false;   /* no change */
 252
 253         br_stp_change_bridge_id(br, addr);
 254         return true;
 255 }
 256
 257 /* Acquires and releases bridge lock */
 258 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 259 {
 260         struct net_bridge_port *p;
 261         int wasroot;
 262
 263         spin_lock_bh(&br->lock);
 264         wasroot = br_is_root_bridge(br);
 265
 266         list_for_each_entry(p, &br->port_list, list) {
 267                 if (p->state != BR_STATE_DISABLED &&
 268                     br_is_designated_port(p)) {
 269                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 270                         p->designated_bridge.prio[1] = newprio & 0xFF;
 271                 }
 272
 273         }
 274
 275         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 276         br->bridge_id.prio[1] = newprio & 0xFF;
 277         br_configuration_update(br);
 278         br_port_state_selection(br);
 279         if (br_is_root_bridge(br) && !wasroot)
 280                 br_become_root_bridge(br);
 281         spin_unlock_bh(&br->lock);
 282 }
 283
 284 /* called under bridge lock */
 285 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
 286 {
 287         port_id new_port_id;
 288
 289         if (newprio > BR_MAX_PORT_PRIORITY)
 290                 return -ERANGE;
 291
 292         new_port_id = br_make_port_id(newprio, p->port_no);
 293         if (br_is_designated_port(p))
 294                 p->designated_port = new_port_id;
 295
 296         p->port_id = new_port_id;
 297         p->priority = newprio;
 298         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 299             p->port_id < p->designated_port) {
 300                 br_become_designated_port(p);
 301                 br_port_state_selection(p->br);
 302         }
 303
 304         return 0;
 305 }
 306
 307 /* called under bridge lock */
 308 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
 309 {
 310         if (path_cost < BR_MIN_PATH_COST ||
 311             path_cost > BR_MAX_PATH_COST)
 312                 return -ERANGE;
 313
 314         p->flags |= BR_ADMIN_COST;
 315         p->path_cost = path_cost;
 316         br_configuration_update(p->br);
 317         br_port_state_selection(p->br);
 318         return 0;
 319 }
 320
 321 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 322 {
 323         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 324                id->prio[0], id->prio[1],
 325                id->addr[0], id->addr[1], id->addr[2],
 326                id->addr[3], id->addr[4], id->addr[5]);
 327 }