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