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 br_ifinfo_notify(RTM_NEWLINK, p); 92 } 93 94 /* called under bridge lock */ 95 void br_stp_disable_port(struct net_bridge_port *p) 96 { 97 struct net_bridge *br = p->br; 98 int wasroot; 99 100 br_log_state(p); 101 102 wasroot = br_is_root_bridge(br); 103 br_become_designated_port(p); 104 p->state = BR_STATE_DISABLED; 105 p->topology_change_ack = 0; 106 p->config_pending = 0; 107 108 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 if (r == 0) { 133 br->stp_enabled = BR_USER_STP; 134 br_debug(br, "userspace STP started\n"); 135 } else { 136 br->stp_enabled = BR_KERNEL_STP; 137 br_debug(br, "using kernel STP\n"); 138 139 /* To start timers on any ports left in blocking */ 140 spin_lock_bh(&br->lock); 141 br_port_state_selection(br); 142 spin_unlock_bh(&br->lock); 143 } 144 } 145 146 static void br_stp_stop(struct net_bridge *br) 147 { 148 int r; 149 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL }; 150 char *envp[] = { NULL }; 151 152 if (br->stp_enabled == BR_USER_STP) { 153 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 154 br_info(br, "userspace STP stopped, return code %d\n", r); 155 156 /* To start timers on any ports left in blocking */ 157 spin_lock_bh(&br->lock); 158 br_port_state_selection(br); 159 spin_unlock_bh(&br->lock); 160 } 161 162 br->stp_enabled = BR_NO_STP; 163 } 164 165 void br_stp_set_enabled(struct net_bridge *br, unsigned long val) 166 { 167 ASSERT_RTNL(); 168 169 if (val) { 170 if (br->stp_enabled == BR_NO_STP) 171 br_stp_start(br); 172 } else { 173 if (br->stp_enabled != BR_NO_STP) 174 br_stp_stop(br); 175 } 176 } 177 178 /* called under bridge lock */ 179 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) 180 { 181 /* should be aligned on 2 bytes for compare_ether_addr() */ 182 unsigned short oldaddr_aligned[ETH_ALEN >> 1]; 183 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; 184 struct net_bridge_port *p; 185 int wasroot; 186 187 wasroot = br_is_root_bridge(br); 188 189 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); 190 memcpy(br->bridge_id.addr, addr, ETH_ALEN); 191 memcpy(br->dev->dev_addr, addr, ETH_ALEN); 192 193 list_for_each_entry(p, &br->port_list, list) { 194 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr)) 195 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 196 197 if (!compare_ether_addr(p->designated_root.addr, oldaddr)) 198 memcpy(p->designated_root.addr, addr, ETH_ALEN); 199 200 } 201 202 br_configuration_update(br); 203 br_port_state_selection(br); 204 if (br_is_root_bridge(br) && !wasroot) 205 br_become_root_bridge(br); 206 } 207 208 /* should be aligned on 2 bytes for compare_ether_addr() */ 209 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 210 211 /* called under bridge lock */ 212 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 213 { 214 const unsigned char *br_mac_zero = 215 (const unsigned char *)br_mac_zero_aligned; 216 const unsigned char *addr = br_mac_zero; 217 struct net_bridge_port *p; 218 219 /* user has chosen a value so keep it */ 220 if (br->flags & BR_SET_MAC_ADDR) 221 return false; 222 223 list_for_each_entry(p, &br->port_list, list) { 224 if (addr == br_mac_zero || 225 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 226 addr = p->dev->dev_addr; 227 228 } 229 230 if (compare_ether_addr(br->bridge_id.addr, addr) == 0) 231 return false; /* no change */ 232 233 br_stp_change_bridge_id(br, addr); 234 return true; 235 } 236 237 /* called under bridge lock */ 238 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 239 { 240 struct net_bridge_port *p; 241 int wasroot; 242 243 wasroot = br_is_root_bridge(br); 244 245 list_for_each_entry(p, &br->port_list, list) { 246 if (p->state != BR_STATE_DISABLED && 247 br_is_designated_port(p)) { 248 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 249 p->designated_bridge.prio[1] = newprio & 0xFF; 250 } 251 252 } 253 254 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 255 br->bridge_id.prio[1] = newprio & 0xFF; 256 br_configuration_update(br); 257 br_port_state_selection(br); 258 if (br_is_root_bridge(br) && !wasroot) 259 br_become_root_bridge(br); 260 } 261 262 /* called under bridge lock */ 263 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 264 { 265 port_id new_port_id; 266 267 if (newprio > BR_MAX_PORT_PRIORITY) 268 return -ERANGE; 269 270 new_port_id = br_make_port_id(newprio, p->port_no); 271 if (br_is_designated_port(p)) 272 p->designated_port = new_port_id; 273 274 p->port_id = new_port_id; 275 p->priority = newprio; 276 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 277 p->port_id < p->designated_port) { 278 br_become_designated_port(p); 279 br_port_state_selection(p->br); 280 } 281 282 return 0; 283 } 284 285 /* called under bridge lock */ 286 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 287 { 288 if (path_cost < BR_MIN_PATH_COST || 289 path_cost > BR_MAX_PATH_COST) 290 return -ERANGE; 291 292 p->path_cost = path_cost; 293 br_configuration_update(p->br); 294 br_port_state_selection(p->br); 295 return 0; 296 } 297 298 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 299 { 300 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 301 id->prio[0], id->prio[1], 302 id->addr[0], id->addr[1], id->addr[2], 303 id->addr[3], id->addr[4], id->addr[5]); 304 } 305