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 19 #include "br_private.h" 20 #include "br_private_stp.h" 21 22 23 /* Port id is composed of priority and port number. 24 * NB: some bits of priority are dropped to 25 * make room for more ports. 26 */ 27 static inline port_id br_make_port_id(__u8 priority, __u16 port_no) 28 { 29 return ((u16)priority << BR_PORT_BITS) 30 | (port_no & ((1<<BR_PORT_BITS)-1)); 31 } 32 33 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS) 34 35 /* called under bridge lock */ 36 void br_init_port(struct net_bridge_port *p) 37 { 38 p->port_id = br_make_port_id(p->priority, p->port_no); 39 br_become_designated_port(p); 40 br_set_state(p, BR_STATE_BLOCKING); 41 p->topology_change_ack = 0; 42 p->config_pending = 0; 43 } 44 45 /* called under bridge lock */ 46 void br_stp_enable_bridge(struct net_bridge *br) 47 { 48 struct net_bridge_port *p; 49 50 spin_lock_bh(&br->lock); 51 if (br->stp_enabled == BR_KERNEL_STP) 52 mod_timer(&br->hello_timer, jiffies + br->hello_time); 53 mod_timer(&br->gc_timer, jiffies + HZ/10); 54 55 br_config_bpdu_generation(br); 56 57 list_for_each_entry(p, &br->port_list, list) { 58 if (netif_running(p->dev) && netif_oper_up(p->dev)) 59 br_stp_enable_port(p); 60 61 } 62 spin_unlock_bh(&br->lock); 63 } 64 65 /* NO locks held */ 66 void br_stp_disable_bridge(struct net_bridge *br) 67 { 68 struct net_bridge_port *p; 69 70 spin_lock_bh(&br->lock); 71 list_for_each_entry(p, &br->port_list, list) { 72 if (p->state != BR_STATE_DISABLED) 73 br_stp_disable_port(p); 74 75 } 76 77 br->topology_change = 0; 78 br->topology_change_detected = 0; 79 spin_unlock_bh(&br->lock); 80 81 del_timer_sync(&br->hello_timer); 82 del_timer_sync(&br->topology_change_timer); 83 del_timer_sync(&br->tcn_timer); 84 del_timer_sync(&br->gc_timer); 85 } 86 87 /* called under bridge lock */ 88 void br_stp_enable_port(struct net_bridge_port *p) 89 { 90 br_init_port(p); 91 br_port_state_selection(p->br); 92 br_log_state(p); 93 br_ifinfo_notify(RTM_NEWLINK, p); 94 } 95 96 /* called under bridge lock */ 97 void br_stp_disable_port(struct net_bridge_port *p) 98 { 99 struct net_bridge *br = p->br; 100 int wasroot; 101 102 wasroot = br_is_root_bridge(br); 103 br_become_designated_port(p); 104 br_set_state(p, BR_STATE_DISABLED); 105 p->topology_change_ack = 0; 106 p->config_pending = 0; 107 108 br_log_state(p); 109 br_ifinfo_notify(RTM_NEWLINK, p); 110 111 del_timer(&p->message_age_timer); 112 del_timer(&p->forward_delay_timer); 113 del_timer(&p->hold_timer); 114 115 br_fdb_delete_by_port(br, p, 0, 0); 116 br_multicast_disable_port(p); 117 118 br_configuration_update(br); 119 120 br_port_state_selection(br); 121 122 if (br_is_root_bridge(br) && !wasroot) 123 br_become_root_bridge(br); 124 } 125 126 static void br_stp_start(struct net_bridge *br) 127 { 128 int r; 129 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL }; 130 char *envp[] = { NULL }; 131 struct net_bridge_port *p; 132 133 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 134 135 spin_lock_bh(&br->lock); 136 137 if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY) 138 __br_set_forward_delay(br, BR_MIN_FORWARD_DELAY); 139 else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY) 140 __br_set_forward_delay(br, BR_MAX_FORWARD_DELAY); 141 142 if (r == 0) { 143 br->stp_enabled = BR_USER_STP; 144 br_debug(br, "userspace STP started\n"); 145 /* Stop hello and hold timers */ 146 del_timer(&br->hello_timer); 147 list_for_each_entry(p, &br->port_list, list) 148 del_timer(&p->hold_timer); 149 } else { 150 br->stp_enabled = BR_KERNEL_STP; 151 br_debug(br, "using kernel STP\n"); 152 153 /* To start timers on any ports left in blocking */ 154 br_port_state_selection(br); 155 } 156 157 spin_unlock_bh(&br->lock); 158 } 159 160 static void br_stp_stop(struct net_bridge *br) 161 { 162 int r; 163 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL }; 164 char *envp[] = { NULL }; 165 struct net_bridge_port *p; 166 167 if (br->stp_enabled == BR_USER_STP) { 168 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 169 br_info(br, "userspace STP stopped, return code %d\n", r); 170 171 /* To start timers on any ports left in blocking */ 172 mod_timer(&br->hello_timer, jiffies + br->hello_time); 173 list_for_each_entry(p, &br->port_list, list) 174 mod_timer(&p->hold_timer, 175 round_jiffies(jiffies + BR_HOLD_TIME)); 176 spin_lock_bh(&br->lock); 177 br_port_state_selection(br); 178 spin_unlock_bh(&br->lock); 179 } 180 181 br->stp_enabled = BR_NO_STP; 182 } 183 184 void br_stp_set_enabled(struct net_bridge *br, unsigned long val) 185 { 186 ASSERT_RTNL(); 187 188 if (val) { 189 if (br->stp_enabled == BR_NO_STP) 190 br_stp_start(br); 191 } else { 192 if (br->stp_enabled != BR_NO_STP) 193 br_stp_stop(br); 194 } 195 } 196 197 /* called under bridge lock */ 198 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) 199 { 200 /* should be aligned on 2 bytes for ether_addr_equal() */ 201 unsigned short oldaddr_aligned[ETH_ALEN >> 1]; 202 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; 203 struct net_bridge_port *p; 204 int wasroot; 205 206 wasroot = br_is_root_bridge(br); 207 208 br_fdb_change_mac_address(br, addr); 209 210 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); 211 memcpy(br->bridge_id.addr, addr, ETH_ALEN); 212 memcpy(br->dev->dev_addr, addr, ETH_ALEN); 213 214 list_for_each_entry(p, &br->port_list, list) { 215 if (ether_addr_equal(p->designated_bridge.addr, oldaddr)) 216 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 217 218 if (ether_addr_equal(p->designated_root.addr, oldaddr)) 219 memcpy(p->designated_root.addr, addr, ETH_ALEN); 220 } 221 222 br_configuration_update(br); 223 br_port_state_selection(br); 224 if (br_is_root_bridge(br) && !wasroot) 225 br_become_root_bridge(br); 226 } 227 228 /* should be aligned on 2 bytes for ether_addr_equal() */ 229 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 230 231 /* called under bridge lock */ 232 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 233 { 234 const unsigned char *br_mac_zero = 235 (const unsigned char *)br_mac_zero_aligned; 236 const unsigned char *addr = br_mac_zero; 237 struct net_bridge_port *p; 238 239 /* user has chosen a value so keep it */ 240 if (br->dev->addr_assign_type == NET_ADDR_SET) 241 return false; 242 243 list_for_each_entry(p, &br->port_list, list) { 244 if (addr == br_mac_zero || 245 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 246 addr = p->dev->dev_addr; 247 248 } 249 250 if (ether_addr_equal(br->bridge_id.addr, addr)) 251 return false; /* no change */ 252 253 br_stp_change_bridge_id(br, addr); 254 return true; 255 } 256 257 /* Acquires and releases bridge lock */ 258 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 259 { 260 struct net_bridge_port *p; 261 int wasroot; 262 263 spin_lock_bh(&br->lock); 264 wasroot = br_is_root_bridge(br); 265 266 list_for_each_entry(p, &br->port_list, list) { 267 if (p->state != BR_STATE_DISABLED && 268 br_is_designated_port(p)) { 269 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 270 p->designated_bridge.prio[1] = newprio & 0xFF; 271 } 272 273 } 274 275 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 276 br->bridge_id.prio[1] = newprio & 0xFF; 277 br_configuration_update(br); 278 br_port_state_selection(br); 279 if (br_is_root_bridge(br) && !wasroot) 280 br_become_root_bridge(br); 281 spin_unlock_bh(&br->lock); 282 } 283 284 /* called under bridge lock */ 285 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 286 { 287 port_id new_port_id; 288 289 if (newprio > BR_MAX_PORT_PRIORITY) 290 return -ERANGE; 291 292 new_port_id = br_make_port_id(newprio, p->port_no); 293 if (br_is_designated_port(p)) 294 p->designated_port = new_port_id; 295 296 p->port_id = new_port_id; 297 p->priority = newprio; 298 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 299 p->port_id < p->designated_port) { 300 br_become_designated_port(p); 301 br_port_state_selection(p->br); 302 } 303 304 return 0; 305 } 306 307 /* called under bridge lock */ 308 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 309 { 310 if (path_cost < BR_MIN_PATH_COST || 311 path_cost > BR_MAX_PATH_COST) 312 return -ERANGE; 313 314 p->flags |= BR_ADMIN_COST; 315 p->path_cost = path_cost; 316 br_configuration_update(p->br); 317 br_port_state_selection(p->br); 318 return 0; 319 } 320 321 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 322 { 323 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 324 id->prio[0], id->prio[1], 325 id->addr[0], id->addr[1], id->addr[2], 326 id->addr[3], id->addr[4], id->addr[5]); 327 } 328