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_timer(&br->gc_timer, jiffies + 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 del_timer_sync(&br->gc_timer); 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, 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, 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 struct net_bridge_port *p; 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"); 172 173 /* Stop hello and hold timers */ 174 del_timer(&br->hello_timer); 175 list_for_each_entry(p, &br->port_list, list) 176 del_timer(&p->hold_timer); 177 } else { 178 br->stp_enabled = BR_KERNEL_STP; 179 br_debug(br, "using kernel STP\n"); 180 181 /* To start timers on any ports left in blocking */ 182 br_port_state_selection(br); 183 } 184 185 spin_unlock_bh(&br->lock); 186 } 187 188 static void br_stp_stop(struct net_bridge *br) 189 { 190 struct net_bridge_port *p; 191 int err; 192 193 if (br->stp_enabled == BR_USER_STP) { 194 err = br_stp_call_user(br, "stop"); 195 if (err) 196 br_err(br, "failed to stop userspace STP (%d)\n", err); 197 198 /* To start timers on any ports left in blocking */ 199 mod_timer(&br->hello_timer, jiffies + br->hello_time); 200 list_for_each_entry(p, &br->port_list, list) 201 mod_timer(&p->hold_timer, 202 round_jiffies(jiffies + BR_HOLD_TIME)); 203 spin_lock_bh(&br->lock); 204 br_port_state_selection(br); 205 spin_unlock_bh(&br->lock); 206 } 207 208 br->stp_enabled = BR_NO_STP; 209 } 210 211 void br_stp_set_enabled(struct net_bridge *br, unsigned long val) 212 { 213 ASSERT_RTNL(); 214 215 if (val) { 216 if (br->stp_enabled == BR_NO_STP) 217 br_stp_start(br); 218 } else { 219 if (br->stp_enabled != BR_NO_STP) 220 br_stp_stop(br); 221 } 222 } 223 224 /* called under bridge lock */ 225 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) 226 { 227 /* should be aligned on 2 bytes for ether_addr_equal() */ 228 unsigned short oldaddr_aligned[ETH_ALEN >> 1]; 229 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; 230 struct net_bridge_port *p; 231 int wasroot; 232 233 wasroot = br_is_root_bridge(br); 234 235 br_fdb_change_mac_address(br, addr); 236 237 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); 238 memcpy(br->bridge_id.addr, addr, ETH_ALEN); 239 memcpy(br->dev->dev_addr, addr, ETH_ALEN); 240 241 list_for_each_entry(p, &br->port_list, list) { 242 if (ether_addr_equal(p->designated_bridge.addr, oldaddr)) 243 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 244 245 if (ether_addr_equal(p->designated_root.addr, oldaddr)) 246 memcpy(p->designated_root.addr, addr, ETH_ALEN); 247 } 248 249 br_configuration_update(br); 250 br_port_state_selection(br); 251 if (br_is_root_bridge(br) && !wasroot) 252 br_become_root_bridge(br); 253 } 254 255 /* should be aligned on 2 bytes for ether_addr_equal() */ 256 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 257 258 /* called under bridge lock */ 259 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 260 { 261 const unsigned char *br_mac_zero = 262 (const unsigned char *)br_mac_zero_aligned; 263 const unsigned char *addr = br_mac_zero; 264 struct net_bridge_port *p; 265 266 /* user has chosen a value so keep it */ 267 if (br->dev->addr_assign_type == NET_ADDR_SET) 268 return false; 269 270 list_for_each_entry(p, &br->port_list, list) { 271 if (addr == br_mac_zero || 272 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 273 addr = p->dev->dev_addr; 274 275 } 276 277 if (ether_addr_equal(br->bridge_id.addr, addr)) 278 return false; /* no change */ 279 280 br_stp_change_bridge_id(br, addr); 281 return true; 282 } 283 284 /* Acquires and releases bridge lock */ 285 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 286 { 287 struct net_bridge_port *p; 288 int wasroot; 289 290 spin_lock_bh(&br->lock); 291 wasroot = br_is_root_bridge(br); 292 293 list_for_each_entry(p, &br->port_list, list) { 294 if (p->state != BR_STATE_DISABLED && 295 br_is_designated_port(p)) { 296 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 297 p->designated_bridge.prio[1] = newprio & 0xFF; 298 } 299 300 } 301 302 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 303 br->bridge_id.prio[1] = newprio & 0xFF; 304 br_configuration_update(br); 305 br_port_state_selection(br); 306 if (br_is_root_bridge(br) && !wasroot) 307 br_become_root_bridge(br); 308 spin_unlock_bh(&br->lock); 309 } 310 311 /* called under bridge lock */ 312 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 313 { 314 port_id new_port_id; 315 316 if (newprio > BR_MAX_PORT_PRIORITY) 317 return -ERANGE; 318 319 new_port_id = br_make_port_id(newprio, p->port_no); 320 if (br_is_designated_port(p)) 321 p->designated_port = new_port_id; 322 323 p->port_id = new_port_id; 324 p->priority = newprio; 325 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 326 p->port_id < p->designated_port) { 327 br_become_designated_port(p); 328 br_port_state_selection(p->br); 329 } 330 331 return 0; 332 } 333 334 /* called under bridge lock */ 335 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 336 { 337 if (path_cost < BR_MIN_PATH_COST || 338 path_cost > BR_MAX_PATH_COST) 339 return -ERANGE; 340 341 p->flags |= BR_ADMIN_COST; 342 p->path_cost = path_cost; 343 br_configuration_update(p->br); 344 br_port_state_selection(p->br); 345 return 0; 346 } 347 348 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 349 { 350 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 351 id->prio[0], id->prio[1], 352 id->addr[0], id->addr[1], id->addr[2], 353 id->addr[3], id->addr[4], id->addr[5]); 354 } 355