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/etherdevice.h> 16 #include <linux/rtnetlink.h> 17 18 #include "br_private.h" 19 #include "br_private_stp.h" 20 21 22 /* Port id is composed of priority and port number. 23 * NB: some bits of priority are dropped to 24 * make room for more ports. 25 */ 26 static inline port_id br_make_port_id(__u8 priority, __u16 port_no) 27 { 28 return ((u16)priority << BR_PORT_BITS) 29 | (port_no & ((1<<BR_PORT_BITS)-1)); 30 } 31 32 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS) 33 34 /* called under bridge lock */ 35 void br_init_port(struct net_bridge_port *p) 36 { 37 p->port_id = br_make_port_id(p->priority, p->port_no); 38 br_become_designated_port(p); 39 p->state = BR_STATE_BLOCKING; 40 p->topology_change_ack = 0; 41 p->config_pending = 0; 42 } 43 44 /* called under bridge lock */ 45 void br_stp_enable_bridge(struct net_bridge *br) 46 { 47 struct net_bridge_port *p; 48 49 spin_lock_bh(&br->lock); 50 mod_timer(&br->hello_timer, jiffies + br->hello_time); 51 mod_timer(&br->gc_timer, jiffies + HZ/10); 52 53 br_config_bpdu_generation(br); 54 55 list_for_each_entry(p, &br->port_list, list) { 56 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev)) 57 br_stp_enable_port(p); 58 59 } 60 spin_unlock_bh(&br->lock); 61 } 62 63 /* NO locks held */ 64 void br_stp_disable_bridge(struct net_bridge *br) 65 { 66 struct net_bridge_port *p; 67 68 spin_lock_bh(&br->lock); 69 list_for_each_entry(p, &br->port_list, list) { 70 if (p->state != BR_STATE_DISABLED) 71 br_stp_disable_port(p); 72 73 } 74 75 br->topology_change = 0; 76 br->topology_change_detected = 0; 77 spin_unlock_bh(&br->lock); 78 79 del_timer_sync(&br->hello_timer); 80 del_timer_sync(&br->topology_change_timer); 81 del_timer_sync(&br->tcn_timer); 82 del_timer_sync(&br->gc_timer); 83 } 84 85 /* called under bridge lock */ 86 void br_stp_enable_port(struct net_bridge_port *p) 87 { 88 br_init_port(p); 89 br_port_state_selection(p->br); 90 br_log_state(p); 91 } 92 93 /* called under bridge lock */ 94 void br_stp_disable_port(struct net_bridge_port *p) 95 { 96 struct net_bridge *br = p->br; 97 int wasroot; 98 99 br_log_state(p); 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 del_timer(&p->message_age_timer); 108 del_timer(&p->forward_delay_timer); 109 del_timer(&p->hold_timer); 110 111 br_fdb_delete_by_port(br, p, 0); 112 br_multicast_disable_port(p); 113 114 br_configuration_update(br); 115 116 br_port_state_selection(br); 117 118 if (br_is_root_bridge(br) && !wasroot) 119 br_become_root_bridge(br); 120 } 121 122 static void br_stp_start(struct net_bridge *br) 123 { 124 int r; 125 char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL }; 126 char *envp[] = { NULL }; 127 128 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 129 if (r == 0) { 130 br->stp_enabled = BR_USER_STP; 131 br_debug(br, "userspace STP started\n"); 132 } else { 133 br->stp_enabled = BR_KERNEL_STP; 134 br_debug(br, "using kernel STP\n"); 135 136 /* To start timers on any ports left in blocking */ 137 spin_lock_bh(&br->lock); 138 br_port_state_selection(br); 139 spin_unlock_bh(&br->lock); 140 } 141 } 142 143 static void br_stp_stop(struct net_bridge *br) 144 { 145 int r; 146 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL }; 147 char *envp[] = { NULL }; 148 149 if (br->stp_enabled == BR_USER_STP) { 150 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 151 br_info(br, "userspace STP stopped, return code %d\n", r); 152 153 /* To start timers on any ports left in blocking */ 154 spin_lock_bh(&br->lock); 155 br_port_state_selection(br); 156 spin_unlock_bh(&br->lock); 157 } 158 159 br->stp_enabled = BR_NO_STP; 160 } 161 162 void br_stp_set_enabled(struct net_bridge *br, unsigned long val) 163 { 164 ASSERT_RTNL(); 165 166 if (val) { 167 if (br->stp_enabled == BR_NO_STP) 168 br_stp_start(br); 169 } else { 170 if (br->stp_enabled != BR_NO_STP) 171 br_stp_stop(br); 172 } 173 } 174 175 /* called under bridge lock */ 176 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) 177 { 178 /* should be aligned on 2 bytes for compare_ether_addr() */ 179 unsigned short oldaddr_aligned[ETH_ALEN >> 1]; 180 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; 181 struct net_bridge_port *p; 182 int wasroot; 183 184 wasroot = br_is_root_bridge(br); 185 186 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); 187 memcpy(br->bridge_id.addr, addr, ETH_ALEN); 188 memcpy(br->dev->dev_addr, addr, ETH_ALEN); 189 190 list_for_each_entry(p, &br->port_list, list) { 191 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr)) 192 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 193 194 if (!compare_ether_addr(p->designated_root.addr, oldaddr)) 195 memcpy(p->designated_root.addr, addr, ETH_ALEN); 196 197 } 198 199 br_configuration_update(br); 200 br_port_state_selection(br); 201 if (br_is_root_bridge(br) && !wasroot) 202 br_become_root_bridge(br); 203 } 204 205 /* should be aligned on 2 bytes for compare_ether_addr() */ 206 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 207 208 /* called under bridge lock */ 209 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 210 { 211 const unsigned char *br_mac_zero = 212 (const unsigned char *)br_mac_zero_aligned; 213 const unsigned char *addr = br_mac_zero; 214 struct net_bridge_port *p; 215 216 /* user has chosen a value so keep it */ 217 if (br->flags & BR_SET_MAC_ADDR) 218 return false; 219 220 list_for_each_entry(p, &br->port_list, list) { 221 if (addr == br_mac_zero || 222 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 223 addr = p->dev->dev_addr; 224 225 } 226 227 if (compare_ether_addr(br->bridge_id.addr, addr) == 0) 228 return false; /* no change */ 229 230 br_stp_change_bridge_id(br, addr); 231 return true; 232 } 233 234 /* called under bridge lock */ 235 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 236 { 237 struct net_bridge_port *p; 238 int wasroot; 239 240 wasroot = br_is_root_bridge(br); 241 242 list_for_each_entry(p, &br->port_list, list) { 243 if (p->state != BR_STATE_DISABLED && 244 br_is_designated_port(p)) { 245 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 246 p->designated_bridge.prio[1] = newprio & 0xFF; 247 } 248 249 } 250 251 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 252 br->bridge_id.prio[1] = newprio & 0xFF; 253 br_configuration_update(br); 254 br_port_state_selection(br); 255 if (br_is_root_bridge(br) && !wasroot) 256 br_become_root_bridge(br); 257 } 258 259 /* called under bridge lock */ 260 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 261 { 262 port_id new_port_id; 263 264 if (newprio > BR_MAX_PORT_PRIORITY) 265 return -ERANGE; 266 267 new_port_id = br_make_port_id(newprio, p->port_no); 268 if (br_is_designated_port(p)) 269 p->designated_port = new_port_id; 270 271 p->port_id = new_port_id; 272 p->priority = newprio; 273 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 274 p->port_id < p->designated_port) { 275 br_become_designated_port(p); 276 br_port_state_selection(p->br); 277 } 278 279 return 0; 280 } 281 282 /* called under bridge lock */ 283 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 284 { 285 if (path_cost < BR_MIN_PATH_COST || 286 path_cost > BR_MAX_PATH_COST) 287 return -ERANGE; 288 289 p->path_cost = path_cost; 290 br_configuration_update(p->br); 291 br_port_state_selection(p->br); 292 return 0; 293 } 294 295 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 296 { 297 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 298 id->prio[0], id->prio[1], 299 id->addr[0], id->addr[1], id->addr[2], 300 id->addr[3], id->addr[4], id->addr[5]); 301 } 302