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