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 br_log_state(p); 102 103 wasroot = br_is_root_bridge(br); 104 br_become_designated_port(p); 105 p->state = BR_STATE_DISABLED; 106 p->topology_change_ack = 0; 107 p->config_pending = 0; 108 109 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); 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 }; 131 132 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 133 if (r == 0) { 134 br->stp_enabled = BR_USER_STP; 135 br_debug(br, "userspace STP started\n"); 136 } else { 137 br->stp_enabled = BR_KERNEL_STP; 138 br_debug(br, "using kernel STP\n"); 139 140 /* To start timers on any ports left in blocking */ 141 spin_lock_bh(&br->lock); 142 br_port_state_selection(br); 143 spin_unlock_bh(&br->lock); 144 } 145 } 146 147 static void br_stp_stop(struct net_bridge *br) 148 { 149 int r; 150 char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL }; 151 char *envp[] = { NULL }; 152 153 if (br->stp_enabled == BR_USER_STP) { 154 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); 155 br_info(br, "userspace STP stopped, return code %d\n", r); 156 157 /* To start timers on any ports left in blocking */ 158 spin_lock_bh(&br->lock); 159 br_port_state_selection(br); 160 spin_unlock_bh(&br->lock); 161 } 162 163 br->stp_enabled = BR_NO_STP; 164 } 165 166 void br_stp_set_enabled(struct net_bridge *br, unsigned long val) 167 { 168 ASSERT_RTNL(); 169 170 if (val) { 171 if (br->stp_enabled == BR_NO_STP) 172 br_stp_start(br); 173 } else { 174 if (br->stp_enabled != BR_NO_STP) 175 br_stp_stop(br); 176 } 177 } 178 179 /* called under bridge lock */ 180 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) 181 { 182 /* should be aligned on 2 bytes for compare_ether_addr() */ 183 unsigned short oldaddr_aligned[ETH_ALEN >> 1]; 184 unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; 185 struct net_bridge_port *p; 186 int wasroot; 187 188 wasroot = br_is_root_bridge(br); 189 190 memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); 191 memcpy(br->bridge_id.addr, addr, ETH_ALEN); 192 memcpy(br->dev->dev_addr, addr, ETH_ALEN); 193 194 list_for_each_entry(p, &br->port_list, list) { 195 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr)) 196 memcpy(p->designated_bridge.addr, addr, ETH_ALEN); 197 198 if (!compare_ether_addr(p->designated_root.addr, oldaddr)) 199 memcpy(p->designated_root.addr, addr, ETH_ALEN); 200 201 } 202 203 br_configuration_update(br); 204 br_port_state_selection(br); 205 if (br_is_root_bridge(br) && !wasroot) 206 br_become_root_bridge(br); 207 } 208 209 /* should be aligned on 2 bytes for compare_ether_addr() */ 210 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; 211 212 /* called under bridge lock */ 213 bool br_stp_recalculate_bridge_id(struct net_bridge *br) 214 { 215 const unsigned char *br_mac_zero = 216 (const unsigned char *)br_mac_zero_aligned; 217 const unsigned char *addr = br_mac_zero; 218 struct net_bridge_port *p; 219 220 /* user has chosen a value so keep it */ 221 if (br->flags & BR_SET_MAC_ADDR) 222 return false; 223 224 list_for_each_entry(p, &br->port_list, list) { 225 if (addr == br_mac_zero || 226 memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) 227 addr = p->dev->dev_addr; 228 229 } 230 231 if (compare_ether_addr(br->bridge_id.addr, addr) == 0) 232 return false; /* no change */ 233 234 br_stp_change_bridge_id(br, addr); 235 return true; 236 } 237 238 /* called under bridge lock */ 239 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) 240 { 241 struct net_bridge_port *p; 242 int wasroot; 243 244 wasroot = br_is_root_bridge(br); 245 246 list_for_each_entry(p, &br->port_list, list) { 247 if (p->state != BR_STATE_DISABLED && 248 br_is_designated_port(p)) { 249 p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; 250 p->designated_bridge.prio[1] = newprio & 0xFF; 251 } 252 253 } 254 255 br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; 256 br->bridge_id.prio[1] = newprio & 0xFF; 257 br_configuration_update(br); 258 br_port_state_selection(br); 259 if (br_is_root_bridge(br) && !wasroot) 260 br_become_root_bridge(br); 261 } 262 263 /* called under bridge lock */ 264 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) 265 { 266 port_id new_port_id; 267 268 if (newprio > BR_MAX_PORT_PRIORITY) 269 return -ERANGE; 270 271 new_port_id = br_make_port_id(newprio, p->port_no); 272 if (br_is_designated_port(p)) 273 p->designated_port = new_port_id; 274 275 p->port_id = new_port_id; 276 p->priority = newprio; 277 if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && 278 p->port_id < p->designated_port) { 279 br_become_designated_port(p); 280 br_port_state_selection(p->br); 281 } 282 283 return 0; 284 } 285 286 /* called under bridge lock */ 287 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) 288 { 289 if (path_cost < BR_MIN_PATH_COST || 290 path_cost > BR_MAX_PATH_COST) 291 return -ERANGE; 292 293 p->path_cost = path_cost; 294 br_configuration_update(p->br); 295 br_port_state_selection(p->br); 296 return 0; 297 } 298 299 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) 300 { 301 return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", 302 id->prio[0], id->prio[1], 303 id->addr[0], id->addr[1], id->addr[2], 304 id->addr[3], id->addr[4], id->addr[5]); 305 } 306