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