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 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME, 41 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER, 42 .u.ageing_time = p->br->ageing_time, 43 }; 44 int err; 45 46 p->port_id = br_make_port_id(p->priority, p->port_no); 47 br_become_designated_port(p); 48 br_set_state(p, BR_STATE_BLOCKING); 49 p->topology_change_ack = 0; 50 p->config_pending = 0; 51 52 err = switchdev_port_attr_set(p->dev, &attr); 53 if (err && err != -EOPNOTSUPP) 54 netdev_err(p->dev, "failed to set HW ageing time\n"); 55 } 56 57 /* called under bridge lock */ 58 void br_stp_enable_bridge(struct net_bridge *br) 59 { 60 struct net_bridge_port *p; 61 62 spin_lock_bh(&br->lock); 63 if (br->stp_enabled == BR_KERNEL_STP) 64 mod_timer(&br->hello_timer, jiffies + br->hello_time); 65 mod_timer(&br->gc_timer, jiffies + HZ/10); 66 67 br_config_bpdu_generation(br); 68 69 list_for_each_entry(p, &br->port_list, list) { 70 if (netif_running(p->dev) && netif_oper_up(p->dev)) 71 br_stp_enable_port(p); 72 73 } 74 spin_unlock_bh(&br->lock); 75 } 76 77 /* NO locks held */ 78 void br_stp_disable_bridge(struct net_bridge *br) 79 { 80 struct net_bridge_port *p; 81 82 spin_lock_bh(&br->lock); 83 list_for_each_entry(p, &br->port_list, list) { 84 if (p->state != BR_STATE_DISABLED) 85 br_stp_disable_port(p); 86 87 } 88 89 br->topology_change = 0; 90 br->topology_change_detected = 0; 91 spin_unlock_bh(&br->lock); 92 93 del_timer_sync(&br->hello_timer); 94 del_timer_sync(&br->topology_change_timer); 95 del_timer_sync(&br->tcn_timer); 96 del_timer_sync(&br->gc_timer); 97 } 98 99 /* called under bridge lock */ 100 void br_stp_enable_port(struct net_bridge_port *p) 101 { 102 br_init_port(p); 103 br_port_state_selection(p->br); 104 br_log_state(p); 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_log_state(p); 121 br_ifinfo_notify(RTM_NEWLINK, p); 122 123 del_timer(&p->message_age_timer); 124 del_timer(&p->forward_delay_timer); 125 del_timer(&p->hold_timer); 126 127 br_fdb_delete_by_port(br, p, 0, 0); 128 br_multicast_disable_port(p); 129 130 br_configuration_update(br); 131 132 br_port_state_selection(br); 133 134 if (br_is_root_bridge(br) && !wasroot) 135 br_become_root_bridge(br); 136 } 137 138 static void br_stp_start(struct net_bridge *br) 139 { 140 int r; 141 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL }; 142 char *envp[] = { NULL }; 143 struct net_bridge_port *p; 144 145 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 146 147 spin_lock_bh(&br->lock); 148 149 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY) 150 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY); 151 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY) 152 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY); 153 154 if (r == 0) { 155 br->stp_enabled = BR_USER_STP; 156 br_debug(br, "userspace STP started\n"); 157 /* Stop hello and hold timers */ 158 del_timer(&br->hello_timer); 159 list_for_each_entry(p, &br->port_list, list) 160 del_timer(&p->hold_timer); 161 } else { 162 br->stp_enabled = BR_KERNEL_STP; 163 br_debug(br, "using kernel STP\n"); 164 165 /* To start timers on any ports left in blocking */ 166 br_port_state_selection(br); 167 } 168 169 spin_unlock_bh(&br->lock); 170 } 171 172 static void br_stp_stop(struct net_bridge *br) 173 { 174 int r; 175 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL }; 176 char *envp[] = { NULL }; 177 struct net_bridge_port *p; 178 179 if (br->stp_enabled == BR_USER_STP) { 180 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 181 br_info(br, "userspace STP stopped, return code %d\n", r); 182 183 /* To start timers on any ports left in blocking */ 184 mod_timer(&br->hello_timer, jiffies + br->hello_time); 185 list_for_each_entry(p, &br->port_list, list) 186 mod_timer(&p->hold_timer, 187 round_jiffies(jiffies + BR_HOLD_TIME)); 188 spin_lock_bh(&br->lock); 189 br_port_state_selection(br); 190 spin_unlock_bh(&br->lock); 191 } 192 193 br->stp_enabled = BR_NO_STP; 194 } 195 196 void br_stp_set_enabled(struct net_bridge *br, unsigned long val) 197 { 198 ASSERT_RTNL(); 199 200 if (val) { 201 if (br->stp_enabled == BR_NO_STP) 202 br_stp_start(br); 203 } else { 204 if (br->stp_enabled != BR_NO_STP) 205 br_stp_stop(br); 206 } 207 } 208 209 /* called under bridge lock */ 210 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) 211 { 212 /* should be aligned on 2 bytes for ether_addr_equal() */ 213 unsigned short oldaddr_aligned[ETH_ALEN >> 1]; 214 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; 215 struct net_bridge_port *p; 216 int wasroot; 217 218 wasroot = br_is_root_bridge(br); 219 220 br_fdb_change_mac_address(br, addr); 221 222 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); 223 memcpy(br->bridge_id.addr, addr, ETH_ALEN); 224 memcpy(br->dev->dev_addr, addr, ETH_ALEN); 225 226 list_for_each_entry(p, &br->port_list, list) { 227 if (ether_addr_equal(p->designated_bridge.addr, oldaddr)) 228 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 229 230 if (ether_addr_equal(p->designated_root.addr, oldaddr)) 231 memcpy(p->designated_root.addr, addr, ETH_ALEN); 232 } 233 234 br_configuration_update(br); 235 br_port_state_selection(br); 236 if (br_is_root_bridge(br) && !wasroot) 237 br_become_root_bridge(br); 238 } 239 240 /* should be aligned on 2 bytes for ether_addr_equal() */ 241 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 242 243 /* called under bridge lock */ 244 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 245 { 246 const unsigned char *br_mac_zero = 247 (const unsigned char *)br_mac_zero_aligned; 248 const unsigned char *addr = br_mac_zero; 249 struct net_bridge_port *p; 250 251 /* user has chosen a value so keep it */ 252 if (br->dev->addr_assign_type == NET_ADDR_SET) 253 return false; 254 255 list_for_each_entry(p, &br->port_list, list) { 256 if (addr == br_mac_zero || 257 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 258 addr = p->dev->dev_addr; 259 260 } 261 262 if (ether_addr_equal(br->bridge_id.addr, addr)) 263 return false; /* no change */ 264 265 br_stp_change_bridge_id(br, addr); 266 return true; 267 } 268 269 /* Acquires and releases bridge lock */ 270 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 271 { 272 struct net_bridge_port *p; 273 int wasroot; 274 275 spin_lock_bh(&br->lock); 276 wasroot = br_is_root_bridge(br); 277 278 list_for_each_entry(p, &br->port_list, list) { 279 if (p->state != BR_STATE_DISABLED && 280 br_is_designated_port(p)) { 281 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 282 p->designated_bridge.prio[1] = newprio & 0xFF; 283 } 284 285 } 286 287 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 288 br->bridge_id.prio[1] = newprio & 0xFF; 289 br_configuration_update(br); 290 br_port_state_selection(br); 291 if (br_is_root_bridge(br) && !wasroot) 292 br_become_root_bridge(br); 293 spin_unlock_bh(&br->lock); 294 } 295 296 /* called under bridge lock */ 297 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 298 { 299 port_id new_port_id; 300 301 if (newprio > BR_MAX_PORT_PRIORITY) 302 return -ERANGE; 303 304 new_port_id = br_make_port_id(newprio, p->port_no); 305 if (br_is_designated_port(p)) 306 p->designated_port = new_port_id; 307 308 p->port_id = new_port_id; 309 p->priority = newprio; 310 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 311 p->port_id < p->designated_port) { 312 br_become_designated_port(p); 313 br_port_state_selection(p->br); 314 } 315 316 return 0; 317 } 318 319 /* called under bridge lock */ 320 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 321 { 322 if (path_cost < BR_MIN_PATH_COST || 323 path_cost > BR_MAX_PATH_COST) 324 return -ERANGE; 325 326 p->flags |= BR_ADMIN_COST; 327 p->path_cost = path_cost; 328 br_configuration_update(p->br); 329 br_port_state_selection(p->br); 330 return 0; 331 } 332 333 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 334 { 335 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 336 id->prio[0], id->prio[1], 337 id->addr[0], id->addr[1], id->addr[2], 338 id->addr[3], id->addr[4], id->addr[5]); 339 } 340