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 #include <net/switchdev.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: some 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 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
  35
  36 /* called under bridge lock */
  37 void br_init_port(struct net_bridge_port *p)
  38 {
  39         struct switchdev_attr attr = {
  40                 .orig_dev = p->dev,
  41                 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
  42                 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
  43                 .u.ageing_time = jiffies_to_clock_t(p->br->ageing_time),
  44         };
  45         int err;
  46
  47         p->port_id = br_make_port_id(p->priority, p->port_no);
  48         br_become_designated_port(p);
  49         br_set_state(p, BR_STATE_BLOCKING);
  50         p->topology_change_ack = 0;
  51         p->config_pending = 0;
  52
  53         err = switchdev_port_attr_set(p->dev, &attr);
  54         if (err && err != -EOPNOTSUPP)
  55                 netdev_err(p->dev, "failed to set HW ageing time\n");
  56 }
  57
  58 /* NO locks held */
  59 void br_stp_enable_bridge(struct net_bridge *br)
  60 {
  61         struct net_bridge_port *p;
  62
  63         spin_lock_bh(&br->lock);
  64         if (br->stp_enabled == BR_KERNEL_STP)
  65                 mod_timer(&br->hello_timer, jiffies + br->hello_time);
  66         mod_timer(&br->gc_timer, jiffies + HZ/10);
  67
  68         br_config_bpdu_generation(br);
  69
  70         list_for_each_entry(p, &br->port_list, list) {
  71                 if (netif_running(p->dev) && netif_oper_up(p->dev))
  72                         br_stp_enable_port(p);
  73
  74         }
  75         spin_unlock_bh(&br->lock);
  76 }
  77
  78 /* NO locks held */
  79 void br_stp_disable_bridge(struct net_bridge *br)
  80 {
  81         struct net_bridge_port *p;
  82
  83         spin_lock_bh(&br->lock);
  84         list_for_each_entry(p, &br->port_list, list) {
  85                 if (p->state != BR_STATE_DISABLED)
  86                         br_stp_disable_port(p);
  87
  88         }
  89
  90         br->topology_change = 0;
  91         br->topology_change_detected = 0;
  92         spin_unlock_bh(&br->lock);
  93
  94         del_timer_sync(&br->hello_timer);
  95         del_timer_sync(&br->topology_change_timer);
  96         del_timer_sync(&br->tcn_timer);
  97         del_timer_sync(&br->gc_timer);
  98 }
  99
 100 /* called under bridge lock */
 101 void br_stp_enable_port(struct net_bridge_port *p)
 102 {
 103         br_init_port(p);
 104         br_port_state_selection(p->br);
 105         br_ifinfo_notify(RTM_NEWLINK, p);
 106 }
 107
 108 /* called under bridge lock */
 109 void br_stp_disable_port(struct net_bridge_port *p)
 110 {
 111         struct net_bridge *br = p->br;
 112         int wasroot;
 113
 114         wasroot = br_is_root_bridge(br);
 115         br_become_designated_port(p);
 116         br_set_state(p, BR_STATE_DISABLED);
 117         p->topology_change_ack = 0;
 118         p->config_pending = 0;
 119
 120         br_ifinfo_notify(RTM_NEWLINK, p);
 121
 122         del_timer(&p->message_age_timer);
 123         del_timer(&p->forward_delay_timer);
 124         del_timer(&p->hold_timer);
 125
 126         br_fdb_delete_by_port(br, p, 0, 0);
 127         br_multicast_disable_port(p);
 128
 129         br_configuration_update(br);
 130
 131         br_port_state_selection(br);
 132
 133         if (br_is_root_bridge(br) && !wasroot)
 134                 br_become_root_bridge(br);
 135 }
 136
 137 static int br_stp_call_user(struct net_bridge *br, char *arg)
 138 {
 139         char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL };
 140         char *envp[] = { NULL };
 141         int rc;
 142
 143         /* call userspace STP and report program errors */
 144         rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 145         if (rc > 0) {
 146                 if (rc & 0xff)
 147                         br_debug(br, BR_STP_PROG " received signal %d\n",
 148                                  rc & 0x7f);
 149                 else
 150                         br_debug(br, BR_STP_PROG " exited with code %d\n",
 151                                  (rc >> 8) & 0xff);
 152         }
 153
 154         return rc;
 155 }
 156
 157 static void br_stp_start(struct net_bridge *br)
 158 {
 159         struct net_bridge_port *p;
 160         int err = -ENOENT;
 161
 162         if (net_eq(dev_net(br->dev), &init_net))
 163                 err = br_stp_call_user(br, "start");
 164
 165         if (err && err != -ENOENT)
 166                 br_err(br, "failed to start userspace STP (%d)\n", err);
 167
 168         spin_lock_bh(&br->lock);
 169
 170         if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
 171                 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
 172         else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
 173                 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
 174
 175         if (!err) {
 176                 br->stp_enabled = BR_USER_STP;
 177                 br_debug(br, "userspace STP started\n");
 178
 179                 /* Stop hello and hold timers */
 180                 del_timer(&br->hello_timer);
 181                 list_for_each_entry(p, &br->port_list, list)
 182                         del_timer(&p->hold_timer);
 183         } else {
 184                 br->stp_enabled = BR_KERNEL_STP;
 185                 br_debug(br, "using kernel STP\n");
 186
 187                 /* To start timers on any ports left in blocking */
 188                 br_port_state_selection(br);
 189         }
 190
 191         spin_unlock_bh(&br->lock);
 192 }
 193
 194 static void br_stp_stop(struct net_bridge *br)
 195 {
 196         struct net_bridge_port *p;
 197         int err;
 198
 199         if (br->stp_enabled == BR_USER_STP) {
 200                 err = br_stp_call_user(br, "stop");
 201                 if (err)
 202                         br_err(br, "failed to stop userspace STP (%d)\n", err);
 203
 204                 /* To start timers on any ports left in blocking */
 205                 mod_timer(&br->hello_timer, jiffies + br->hello_time);
 206                 list_for_each_entry(p, &br->port_list, list)
 207                         mod_timer(&p->hold_timer,
 208                                   round_jiffies(jiffies + BR_HOLD_TIME));
 209                 spin_lock_bh(&br->lock);
 210                 br_port_state_selection(br);
 211                 spin_unlock_bh(&br->lock);
 212         }
 213
 214         br->stp_enabled = BR_NO_STP;
 215 }
 216
 217 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 218 {
 219         ASSERT_RTNL();
 220
 221         if (val) {
 222                 if (br->stp_enabled == BR_NO_STP)
 223                         br_stp_start(br);
 224         } else {
 225                 if (br->stp_enabled != BR_NO_STP)
 226                         br_stp_stop(br);
 227         }
 228 }
 229
 230 /* called under bridge lock */
 231 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 232 {
 233         /* should be aligned on 2 bytes for ether_addr_equal() */
 234         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 235         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 236         struct net_bridge_port *p;
 237         int wasroot;
 238
 239         wasroot = br_is_root_bridge(br);
 240
 241         br_fdb_change_mac_address(br, addr);
 242
 243         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 244         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 245         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 246
 247         list_for_each_entry(p, &br->port_list, list) {
 248                 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
 249                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 250
 251                 if (ether_addr_equal(p->designated_root.addr, oldaddr))
 252                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 253         }
 254
 255         br_configuration_update(br);
 256         br_port_state_selection(br);
 257         if (br_is_root_bridge(br) && !wasroot)
 258                 br_become_root_bridge(br);
 259 }
 260
 261 /* should be aligned on 2 bytes for ether_addr_equal() */
 262 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 263
 264 /* called under bridge lock */
 265 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
 266 {
 267         const unsigned char *br_mac_zero =
 268                         (const unsigned char *)br_mac_zero_aligned;
 269         const unsigned char *addr = br_mac_zero;
 270         struct net_bridge_port *p;
 271
 272         /* user has chosen a value so keep it */
 273         if (br->dev->addr_assign_type == NET_ADDR_SET)
 274                 return false;
 275
 276         list_for_each_entry(p, &br->port_list, list) {
 277                 if (addr == br_mac_zero ||
 278                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 279                         addr = p->dev->dev_addr;
 280
 281         }
 282
 283         if (ether_addr_equal(br->bridge_id.addr, addr))
 284                 return false;   /* no change */
 285
 286         br_stp_change_bridge_id(br, addr);
 287         return true;
 288 }
 289
 290 /* Acquires and releases bridge lock */
 291 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 292 {
 293         struct net_bridge_port *p;
 294         int wasroot;
 295
 296         spin_lock_bh(&br->lock);
 297         wasroot = br_is_root_bridge(br);
 298
 299         list_for_each_entry(p, &br->port_list, list) {
 300                 if (p->state != BR_STATE_DISABLED &&
 301                     br_is_designated_port(p)) {
 302                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 303                         p->designated_bridge.prio[1] = newprio & 0xFF;
 304                 }
 305
 306         }
 307
 308         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 309         br->bridge_id.prio[1] = newprio & 0xFF;
 310         br_configuration_update(br);
 311         br_port_state_selection(br);
 312         if (br_is_root_bridge(br) && !wasroot)
 313                 br_become_root_bridge(br);
 314         spin_unlock_bh(&br->lock);
 315 }
 316
 317 /* called under bridge lock */
 318 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
 319 {
 320         port_id new_port_id;
 321
 322         if (newprio > BR_MAX_PORT_PRIORITY)
 323                 return -ERANGE;
 324
 325         new_port_id = br_make_port_id(newprio, p->port_no);
 326         if (br_is_designated_port(p))
 327                 p->designated_port = new_port_id;
 328
 329         p->port_id = new_port_id;
 330         p->priority = newprio;
 331         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 332             p->port_id < p->designated_port) {
 333                 br_become_designated_port(p);
 334                 br_port_state_selection(p->br);
 335         }
 336
 337         return 0;
 338 }
 339
 340 /* called under bridge lock */
 341 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
 342 {
 343         if (path_cost < BR_MIN_PATH_COST ||
 344             path_cost > BR_MAX_PATH_COST)
 345                 return -ERANGE;
 346
 347         p->flags |= BR_ADMIN_COST;
 348         p->path_cost = path_cost;
 349         br_configuration_update(p->br);
 350         br_port_state_selection(p->br);
 351         return 0;
 352 }
 353
 354 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 355 {
 356         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 357                id->prio[0], id->prio[1],
 358                id->addr[0], id->addr[1], id->addr[2],
 359                id->addr[3], id->addr[4], id->addr[5]);
 360 }