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 /* called under bridge lock */
  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_log_state(p);
 106         br_ifinfo_notify(RTM_NEWLINK, p);
 107 }
 108
 109 /* called under bridge lock */
 110 void br_stp_disable_port(struct net_bridge_port *p)
 111 {
 112         struct net_bridge *br = p->br;
 113         int wasroot;
 114
 115         wasroot = br_is_root_bridge(br);
 116         br_become_designated_port(p);
 117         br_set_state(p, BR_STATE_DISABLED);
 118         p->topology_change_ack = 0;
 119         p->config_pending = 0;
 120
 121         br_log_state(p);
 122         br_ifinfo_notify(RTM_NEWLINK, p);
 123
 124         del_timer(&p->message_age_timer);
 125         del_timer(&p->forward_delay_timer);
 126         del_timer(&p->hold_timer);
 127
 128         br_fdb_delete_by_port(br, p, 0, 0);
 129         br_multicast_disable_port(p);
 130
 131         br_configuration_update(br);
 132
 133         br_port_state_selection(br);
 134
 135         if (br_is_root_bridge(br) && !wasroot)
 136                 br_become_root_bridge(br);
 137 }
 138
 139 static void br_stp_start(struct net_bridge *br)
 140 {
 141         int r;
 142         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
 143         char *envp[] = { NULL };
 144         struct net_bridge_port *p;
 145
 146         if (net_eq(dev_net(br->dev), &init_net))
 147                 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 148         else
 149                 r = -ENOENT;
 150
 151         spin_lock_bh(&br->lock);
 152
 153         if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
 154                 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
 155         else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
 156                 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
 157
 158         if (r == 0) {
 159                 br->stp_enabled = BR_USER_STP;
 160                 br_debug(br, "userspace STP started\n");
 161                 /* Stop hello and hold timers */
 162                 del_timer(&br->hello_timer);
 163                 list_for_each_entry(p, &br->port_list, list)
 164                         del_timer(&p->hold_timer);
 165         } else {
 166                 br->stp_enabled = BR_KERNEL_STP;
 167                 br_debug(br, "using kernel STP\n");
 168
 169                 /* To start timers on any ports left in blocking */
 170                 br_port_state_selection(br);
 171         }
 172
 173         spin_unlock_bh(&br->lock);
 174 }
 175
 176 static void br_stp_stop(struct net_bridge *br)
 177 {
 178         int r;
 179         char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
 180         char *envp[] = { NULL };
 181         struct net_bridge_port *p;
 182
 183         if (br->stp_enabled == BR_USER_STP) {
 184                 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 185                 br_info(br, "userspace STP stopped, return code %d\n", r);
 186
 187                 /* To start timers on any ports left in blocking */
 188                 mod_timer(&br->hello_timer, jiffies + br->hello_time);
 189                 list_for_each_entry(p, &br->port_list, list)
 190                         mod_timer(&p->hold_timer,
 191                                   round_jiffies(jiffies + BR_HOLD_TIME));
 192                 spin_lock_bh(&br->lock);
 193                 br_port_state_selection(br);
 194                 spin_unlock_bh(&br->lock);
 195         }
 196
 197         br->stp_enabled = BR_NO_STP;
 198 }
 199
 200 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 201 {
 202         ASSERT_RTNL();
 203
 204         if (val) {
 205                 if (br->stp_enabled == BR_NO_STP)
 206                         br_stp_start(br);
 207         } else {
 208                 if (br->stp_enabled != BR_NO_STP)
 209                         br_stp_stop(br);
 210         }
 211 }
 212
 213 /* called under bridge lock */
 214 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 215 {
 216         /* should be aligned on 2 bytes for ether_addr_equal() */
 217         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 218         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 219         struct net_bridge_port *p;
 220         int wasroot;
 221
 222         wasroot = br_is_root_bridge(br);
 223
 224         br_fdb_change_mac_address(br, addr);
 225
 226         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 227         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 228         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 229
 230         list_for_each_entry(p, &br->port_list, list) {
 231                 if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
 232                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 233
 234                 if (ether_addr_equal(p->designated_root.addr, oldaddr))
 235                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 236         }
 237
 238         br_configuration_update(br);
 239         br_port_state_selection(br);
 240         if (br_is_root_bridge(br) && !wasroot)
 241                 br_become_root_bridge(br);
 242 }
 243
 244 /* should be aligned on 2 bytes for ether_addr_equal() */
 245 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 246
 247 /* called under bridge lock */
 248 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
 249 {
 250         const unsigned char *br_mac_zero =
 251                         (const unsigned char *)br_mac_zero_aligned;
 252         const unsigned char *addr = br_mac_zero;
 253         struct net_bridge_port *p;
 254
 255         /* user has chosen a value so keep it */
 256         if (br->dev->addr_assign_type == NET_ADDR_SET)
 257                 return false;
 258
 259         list_for_each_entry(p, &br->port_list, list) {
 260                 if (addr == br_mac_zero ||
 261                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 262                         addr = p->dev->dev_addr;
 263
 264         }
 265
 266         if (ether_addr_equal(br->bridge_id.addr, addr))
 267                 return false;   /* no change */
 268
 269         br_stp_change_bridge_id(br, addr);
 270         return true;
 271 }
 272
 273 /* Acquires and releases bridge lock */
 274 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 275 {
 276         struct net_bridge_port *p;
 277         int wasroot;
 278
 279         spin_lock_bh(&br->lock);
 280         wasroot = br_is_root_bridge(br);
 281
 282         list_for_each_entry(p, &br->port_list, list) {
 283                 if (p->state != BR_STATE_DISABLED &&
 284                     br_is_designated_port(p)) {
 285                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 286                         p->designated_bridge.prio[1] = newprio & 0xFF;
 287                 }
 288
 289         }
 290
 291         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 292         br->bridge_id.prio[1] = newprio & 0xFF;
 293         br_configuration_update(br);
 294         br_port_state_selection(br);
 295         if (br_is_root_bridge(br) && !wasroot)
 296                 br_become_root_bridge(br);
 297         spin_unlock_bh(&br->lock);
 298 }
 299
 300 /* called under bridge lock */
 301 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
 302 {
 303         port_id new_port_id;
 304
 305         if (newprio > BR_MAX_PORT_PRIORITY)
 306                 return -ERANGE;
 307
 308         new_port_id = br_make_port_id(newprio, p->port_no);
 309         if (br_is_designated_port(p))
 310                 p->designated_port = new_port_id;
 311
 312         p->port_id = new_port_id;
 313         p->priority = newprio;
 314         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 315             p->port_id < p->designated_port) {
 316                 br_become_designated_port(p);
 317                 br_port_state_selection(p->br);
 318         }
 319
 320         return 0;
 321 }
 322
 323 /* called under bridge lock */
 324 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
 325 {
 326         if (path_cost < BR_MIN_PATH_COST ||
 327             path_cost > BR_MAX_PATH_COST)
 328                 return -ERANGE;
 329
 330         p->flags |= BR_ADMIN_COST;
 331         p->path_cost = path_cost;
 332         br_configuration_update(p->br);
 333         br_port_state_selection(p->br);
 334         return 0;
 335 }
 336
 337 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 338 {
 339         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 340                id->prio[0], id->prio[1],
 341                id->addr[0], id->addr[1], id->addr[2],
 342                id->addr[3], id->addr[4], id->addr[5]);
 343 }