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