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 } 347