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         if (!rcu_access_pointer(p->backup_port))
 121                 br_fdb_delete_by_port(br, p, 0, 0);
 122         br_multicast_disable_port(p);
 123
 124         br_configuration_update(br);
 125
 126         br_port_state_selection(br);
 127
 128         if (br_is_root_bridge(br) && !wasroot)
 129                 br_become_root_bridge(br);
 130 }
 131
 132 static int br_stp_call_user(struct net_bridge *br, char *arg)
 133 {
 134         char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL };
 135         char *envp[] = { NULL };
 136         int rc;
 137
 138         /* call userspace STP and report program errors */
 139         rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 140         if (rc > 0) {
 141                 if (rc & 0xff)
 142                         br_debug(br, BR_STP_PROG " received signal %d\n",
 143                                  rc & 0x7f);
 144                 else
 145                         br_debug(br, BR_STP_PROG " exited with code %d\n",
 146                                  (rc >> 8) & 0xff);
 147         }
 148
 149         return rc;
 150 }
 151
 152 static void br_stp_start(struct net_bridge *br)
 153 {
 154         int err = -ENOENT;
 155
 156         if (net_eq(dev_net(br->dev), &init_net))
 157                 err = br_stp_call_user(br, "start");
 158
 159         if (err && err != -ENOENT)
 160                 br_err(br, "failed to start userspace STP (%d)\n", err);
 161
 162         spin_lock_bh(&br->lock);
 163
 164         if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
 165                 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
 166         else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
 167                 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
 168
 169         if (!err) {
 170                 br->stp_enabled = BR_USER_STP;
 171                 br_debug(br, "userspace STP started\n");
 172         } else {
 173                 br->stp_enabled = BR_KERNEL_STP;
 174                 br_debug(br, "using kernel STP\n");
 175
 176                 /* To start timers on any ports left in blocking */
 177                 if (br->dev->flags & IFF_UP)
 178                         mod_timer(&br->hello_timer, jiffies + br->hello_time);
 179                 br_port_state_selection(br);
 180         }
 181
 182         spin_unlock_bh(&br->lock);
 183 }
 184
 185 static void br_stp_stop(struct net_bridge *br)
 186 {
 187         int err;
 188
 189         if (br->stp_enabled == BR_USER_STP) {
 190                 err = br_stp_call_user(br, "stop");
 191                 if (err)
 192                         br_err(br, "failed to stop userspace STP (%d)\n", err);
 193
 194                 /* To start timers on any ports left in blocking */
 195                 spin_lock_bh(&br->lock);
 196                 br_port_state_selection(br);
 197                 spin_unlock_bh(&br->lock);
 198         }
 199
 200         br->stp_enabled = BR_NO_STP;
 201 }
 202
 203 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 204 {
 205         ASSERT_RTNL();
 206
 207         if (val) {
 208                 if (br->stp_enabled == BR_NO_STP)
 209                         br_stp_start(br);
 210         } else {
 211                 if (br->stp_enabled != BR_NO_STP)
 212                         br_stp_stop(br);
 213         }
 214 }
 215
 216 /* called under bridge lock */
 217 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 218 {
 219         /* should be aligned on 2 bytes for ether_addr_equal() */
 220         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 221         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 222         struct net_bridge_port *p;
 223         int wasroot;
 224
 225         wasroot = br_is_root_bridge(br);
 226
 227         br_fdb_change_mac_address(br, addr);
 228
 229         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 230         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 231         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 232
 233         list_for_each_entry(p, &br->port_list, list) {
 234                 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
 235                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 236
 237                 if (ether_addr_equal(p->designated_root.addr, oldaddr))
 238                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 239         }
 240
 241         br_configuration_update(br);
 242         br_port_state_selection(br);
 243         if (br_is_root_bridge(br) && !wasroot)
 244                 br_become_root_bridge(br);
 245 }
 246
 247 /* should be aligned on 2 bytes for ether_addr_equal() */
 248 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 249
 250 /* called under bridge lock */
 251 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
 252 {
 253         const unsigned char *br_mac_zero =
 254                         (const unsigned char *)br_mac_zero_aligned;
 255         const unsigned char *addr = br_mac_zero;
 256         struct net_bridge_port *p;
 257
 258         /* user has chosen a value so keep it */
 259         if (br->dev->addr_assign_type == NET_ADDR_SET)
 260                 return false;
 261
 262         list_for_each_entry(p, &br->port_list, list) {
 263                 if (addr == br_mac_zero ||
 264                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 265                         addr = p->dev->dev_addr;
 266
 267         }
 268
 269         if (ether_addr_equal(br->bridge_id.addr, addr))
 270                 return false;   /* no change */
 271
 272         br_stp_change_bridge_id(br, addr);
 273         return true;
 274 }
 275
 276 /* Acquires and releases bridge lock */
 277 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 278 {
 279         struct net_bridge_port *p;
 280         int wasroot;
 281
 282         spin_lock_bh(&br->lock);
 283         wasroot = br_is_root_bridge(br);
 284
 285         list_for_each_entry(p, &br->port_list, list) {
 286                 if (p->state != BR_STATE_DISABLED &&
 287                     br_is_designated_port(p)) {
 288                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 289                         p->designated_bridge.prio[1] = newprio & 0xFF;
 290                 }
 291
 292         }
 293
 294         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 295         br->bridge_id.prio[1] = newprio & 0xFF;
 296         br_configuration_update(br);
 297         br_port_state_selection(br);
 298         if (br_is_root_bridge(br) && !wasroot)
 299                 br_become_root_bridge(br);
 300         spin_unlock_bh(&br->lock);
 301 }
 302
 303 /* called under bridge lock */
 304 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
 305 {
 306         port_id new_port_id;
 307
 308         if (newprio > BR_MAX_PORT_PRIORITY)
 309                 return -ERANGE;
 310
 311         new_port_id = br_make_port_id(newprio, p->port_no);
 312         if (br_is_designated_port(p))
 313                 p->designated_port = new_port_id;
 314
 315         p->port_id = new_port_id;
 316         p->priority = newprio;
 317         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 318             p->port_id < p->designated_port) {
 319                 br_become_designated_port(p);
 320                 br_port_state_selection(p->br);
 321         }
 322
 323         return 0;
 324 }
 325
 326 /* called under bridge lock */
 327 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
 328 {
 329         if (path_cost < BR_MIN_PATH_COST ||
 330             path_cost > BR_MAX_PATH_COST)
 331                 return -ERANGE;
 332
 333         p->flags |= BR_ADMIN_COST;
 334         p->path_cost = path_cost;
 335         br_configuration_update(p->br);
 336         br_port_state_selection(p->br);
 337         return 0;
 338 }
 339
 340 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 341 {
 342         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 343                id->prio[0], id->prio[1],
 344                id->addr[0], id->addr[1], id->addr[2],
 345                id->addr[3], id->addr[4], id->addr[5]);
 346 }