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 } 344