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 ((p->dev->flags & IFF_UP) && netif_carrier_ok(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 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 ether_addr_equal() */ 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 (ether_addr_equal(p->designated_bridge.addr, oldaddr)) 195 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 196 197 if (ether_addr_equal(p->designated_root.addr, oldaddr)) 198 memcpy(p->designated_root.addr, addr, ETH_ALEN); 199 } 200 201 br_configuration_update(br); 202 br_port_state_selection(br); 203 if (br_is_root_bridge(br) && !wasroot) 204 br_become_root_bridge(br); 205 } 206 207 /* should be aligned on 2 bytes for ether_addr_equal() */ 208 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 209 210 /* called under bridge lock */ 211 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 212 { 213 const unsigned char *br_mac_zero = 214 (const unsigned char *)br_mac_zero_aligned; 215 const unsigned char *addr = br_mac_zero; 216 struct net_bridge_port *p; 217 218 /* user has chosen a value so keep it */ 219 if (br->flags & BR_SET_MAC_ADDR) 220 return false; 221 222 list_for_each_entry(p, &br->port_list, list) { 223 if (addr == br_mac_zero || 224 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 225 addr = p->dev->dev_addr; 226 227 } 228 229 if (ether_addr_equal(br->bridge_id.addr, addr)) 230 return false; /* no change */ 231 232 br_stp_change_bridge_id(br, addr); 233 return true; 234 } 235 236 /* called under bridge lock */ 237 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 238 { 239 struct net_bridge_port *p; 240 int wasroot; 241 242 wasroot = br_is_root_bridge(br); 243 244 list_for_each_entry(p, &br->port_list, list) { 245 if (p->state != BR_STATE_DISABLED && 246 br_is_designated_port(p)) { 247 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 248 p->designated_bridge.prio[1] = newprio & 0xFF; 249 } 250 251 } 252 253 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 254 br->bridge_id.prio[1] = newprio & 0xFF; 255 br_configuration_update(br); 256 br_port_state_selection(br); 257 if (br_is_root_bridge(br) && !wasroot) 258 br_become_root_bridge(br); 259 } 260 261 /* called under bridge lock */ 262 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 263 { 264 port_id new_port_id; 265 266 if (newprio > BR_MAX_PORT_PRIORITY) 267 return -ERANGE; 268 269 new_port_id = br_make_port_id(newprio, p->port_no); 270 if (br_is_designated_port(p)) 271 p->designated_port = new_port_id; 272 273 p->port_id = new_port_id; 274 p->priority = newprio; 275 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 276 p->port_id < p->designated_port) { 277 br_become_designated_port(p); 278 br_port_state_selection(p->br); 279 } 280 281 return 0; 282 } 283 284 /* called under bridge lock */ 285 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 286 { 287 if (path_cost < BR_MIN_PATH_COST || 288 path_cost > BR_MAX_PATH_COST) 289 return -ERANGE; 290 291 p->path_cost = path_cost; 292 br_configuration_update(p->br); 293 br_port_state_selection(p->br); 294 return 0; 295 } 296 297 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 298 { 299 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 300 id->prio[0], id->prio[1], 301 id->addr[0], id->addr[1], id->addr[2], 302 id->addr[3], id->addr[4], id->addr[5]); 303 } 304