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_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_ifinfo_notify(RTM_NEWLINK, p); 121 122 del_timer(&p->message_age_timer); 123 del_timer(&p->forward_delay_timer); 124 del_timer(&p->hold_timer); 125 126 br_fdb_delete_by_port(br, p, 0, 0); 127 br_multicast_disable_port(p); 128 129 br_configuration_update(br); 130 131 br_port_state_selection(br); 132 133 if (br_is_root_bridge(br) && !wasroot) 134 br_become_root_bridge(br); 135 } 136 137 static void br_stp_start(struct net_bridge *br) 138 { 139 int r; 140 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL }; 141 char *envp[] = { NULL }; 142 struct net_bridge_port *p; 143 144 if (net_eq(dev_net(br->dev), &init_net)) 145 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 146 else 147 r = -ENOENT; 148 149 spin_lock_bh(&br->lock); 150 151 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY) 152 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY); 153 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY) 154 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY); 155 156 if (r == 0) { 157 br->stp_enabled = BR_USER_STP; 158 br_debug(br, "userspace STP started\n"); 159 /* Stop hello and hold timers */ 160 del_timer(&br->hello_timer); 161 list_for_each_entry(p, &br->port_list, list) 162 del_timer(&p->hold_timer); 163 } else { 164 br->stp_enabled = BR_KERNEL_STP; 165 br_debug(br, "using kernel STP\n"); 166 167 /* To start timers on any ports left in blocking */ 168 br_port_state_selection(br); 169 } 170 171 spin_unlock_bh(&br->lock); 172 } 173 174 static void br_stp_stop(struct net_bridge *br) 175 { 176 int r; 177 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL }; 178 char *envp[] = { NULL }; 179 struct net_bridge_port *p; 180 181 if (br->stp_enabled == BR_USER_STP) { 182 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 183 br_info(br, "userspace STP stopped, return code %d\n", r); 184 185 /* To start timers on any ports left in blocking */ 186 mod_timer(&br->hello_timer, jiffies + br->hello_time); 187 list_for_each_entry(p, &br->port_list, list) 188 mod_timer(&p->hold_timer, 189 round_jiffies(jiffies + BR_HOLD_TIME)); 190 spin_lock_bh(&br->lock); 191 br_port_state_selection(br); 192 spin_unlock_bh(&br->lock); 193 } 194 195 br->stp_enabled = BR_NO_STP; 196 } 197 198 void br_stp_set_enabled(struct net_bridge *br, unsigned long val) 199 { 200 ASSERT_RTNL(); 201 202 if (val) { 203 if (br->stp_enabled == BR_NO_STP) 204 br_stp_start(br); 205 } else { 206 if (br->stp_enabled != BR_NO_STP) 207 br_stp_stop(br); 208 } 209 } 210 211 /* called under bridge lock */ 212 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) 213 { 214 /* should be aligned on 2 bytes for ether_addr_equal() */ 215 unsigned short oldaddr_aligned[ETH_ALEN >> 1]; 216 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; 217 struct net_bridge_port *p; 218 int wasroot; 219 220 wasroot = br_is_root_bridge(br); 221 222 br_fdb_change_mac_address(br, addr); 223 224 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); 225 memcpy(br->bridge_id.addr, addr, ETH_ALEN); 226 memcpy(br->dev->dev_addr, addr, ETH_ALEN); 227 228 list_for_each_entry(p, &br->port_list, list) { 229 if (ether_addr_equal(p->designated_bridge.addr, oldaddr)) 230 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 231 232 if (ether_addr_equal(p->designated_root.addr, oldaddr)) 233 memcpy(p->designated_root.addr, addr, ETH_ALEN); 234 } 235 236 br_configuration_update(br); 237 br_port_state_selection(br); 238 if (br_is_root_bridge(br) && !wasroot) 239 br_become_root_bridge(br); 240 } 241 242 /* should be aligned on 2 bytes for ether_addr_equal() */ 243 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 244 245 /* called under bridge lock */ 246 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 247 { 248 const unsigned char *br_mac_zero = 249 (const unsigned char *)br_mac_zero_aligned; 250 const unsigned char *addr = br_mac_zero; 251 struct net_bridge_port *p; 252 253 /* user has chosen a value so keep it */ 254 if (br->dev->addr_assign_type == NET_ADDR_SET) 255 return false; 256 257 list_for_each_entry(p, &br->port_list, list) { 258 if (addr == br_mac_zero || 259 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 260 addr = p->dev->dev_addr; 261 262 } 263 264 if (ether_addr_equal(br->bridge_id.addr, addr)) 265 return false; /* no change */ 266 267 br_stp_change_bridge_id(br, addr); 268 return true; 269 } 270 271 /* Acquires and releases bridge lock */ 272 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 273 { 274 struct net_bridge_port *p; 275 int wasroot; 276 277 spin_lock_bh(&br->lock); 278 wasroot = br_is_root_bridge(br); 279 280 list_for_each_entry(p, &br->port_list, list) { 281 if (p->state != BR_STATE_DISABLED && 282 br_is_designated_port(p)) { 283 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 284 p->designated_bridge.prio[1] = newprio & 0xFF; 285 } 286 287 } 288 289 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 290 br->bridge_id.prio[1] = newprio & 0xFF; 291 br_configuration_update(br); 292 br_port_state_selection(br); 293 if (br_is_root_bridge(br) && !wasroot) 294 br_become_root_bridge(br); 295 spin_unlock_bh(&br->lock); 296 } 297 298 /* called under bridge lock */ 299 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 300 { 301 port_id new_port_id; 302 303 if (newprio > BR_MAX_PORT_PRIORITY) 304 return -ERANGE; 305 306 new_port_id = br_make_port_id(newprio, p->port_no); 307 if (br_is_designated_port(p)) 308 p->designated_port = new_port_id; 309 310 p->port_id = new_port_id; 311 p->priority = newprio; 312 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 313 p->port_id < p->designated_port) { 314 br_become_designated_port(p); 315 br_port_state_selection(p->br); 316 } 317 318 return 0; 319 } 320 321 /* called under bridge lock */ 322 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 323 { 324 if (path_cost < BR_MIN_PATH_COST || 325 path_cost > BR_MAX_PATH_COST) 326 return -ERANGE; 327 328 p->flags |= BR_ADMIN_COST; 329 p->path_cost = path_cost; 330 br_configuration_update(p->br); 331 br_port_state_selection(p->br); 332 return 0; 333 } 334 335 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 336 { 337 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 338 id->prio[0], id->prio[1], 339 id->addr[0], id->addr[1], id->addr[2], 340 id->addr[3], id->addr[4], id->addr[5]); 341 } 342