1 /* 2 * Userspace interface 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/netdevice.h> 16 #include <linux/etherdevice.h> 17 #include <linux/netpoll.h> 18 #include <linux/ethtool.h> 19 #include <linux/if_arp.h> 20 #include <linux/module.h> 21 #include <linux/init.h> 22 #include <linux/rtnetlink.h> 23 #include <linux/if_ether.h> 24 #include <linux/slab.h> 25 #include <net/sock.h> 26 27 #include "br_private.h" 28 29 /* 30 * Determine initial path cost based on speed. 31 * using recommendations from 802.1d standard 32 * 33 * Since driver might sleep need to not be holding any locks. 34 */ 35 static int port_cost(struct net_device *dev) 36 { 37 struct ethtool_cmd ecmd; 38 39 if (!__ethtool_get_settings(dev, &ecmd)) { 40 switch (ethtool_cmd_speed(&ecmd)) { 41 case SPEED_10000: 42 return 2; 43 case SPEED_1000: 44 return 4; 45 case SPEED_100: 46 return 19; 47 case SPEED_10: 48 return 100; 49 } 50 } 51 52 /* Old silly heuristics based on name */ 53 if (!strncmp(dev->name, "lec", 3)) 54 return 7; 55 56 if (!strncmp(dev->name, "plip", 4)) 57 return 2500; 58 59 return 100; /* assume old 10Mbps */ 60 } 61 62 63 /* Check for port carrier transistions. */ 64 void br_port_carrier_check(struct net_bridge_port *p) 65 { 66 struct net_device *dev = p->dev; 67 struct net_bridge *br = p->br; 68 69 if (netif_running(dev) && netif_carrier_ok(dev)) 70 p->path_cost = port_cost(dev); 71 72 if (!netif_running(br->dev)) 73 return; 74 75 spin_lock_bh(&br->lock); 76 if (netif_running(dev) && netif_carrier_ok(dev)) { 77 if (p->state == BR_STATE_DISABLED) 78 br_stp_enable_port(p); 79 } else { 80 if (p->state != BR_STATE_DISABLED) 81 br_stp_disable_port(p); 82 } 83 spin_unlock_bh(&br->lock); 84 } 85 86 static void release_nbp(struct kobject *kobj) 87 { 88 struct net_bridge_port *p 89 = container_of(kobj, struct net_bridge_port, kobj); 90 kfree(p); 91 } 92 93 static struct kobj_type brport_ktype = { 94 #ifdef CONFIG_SYSFS 95 .sysfs_ops = &brport_sysfs_ops, 96 #endif 97 .release = release_nbp, 98 }; 99 100 static void destroy_nbp(struct net_bridge_port *p) 101 { 102 struct net_device *dev = p->dev; 103 104 p->br = NULL; 105 p->dev = NULL; 106 dev_put(dev); 107 108 kobject_put(&p->kobj); 109 } 110 111 static void destroy_nbp_rcu(struct rcu_head *head) 112 { 113 struct net_bridge_port *p = 114 container_of(head, struct net_bridge_port, rcu); 115 destroy_nbp(p); 116 } 117 118 /* Delete port(interface) from bridge is done in two steps. 119 * via RCU. First step, marks device as down. That deletes 120 * all the timers and stops new packets from flowing through. 121 * 122 * Final cleanup doesn't occur until after all CPU's finished 123 * processing packets. 124 * 125 * Protected from multiple admin operations by RTNL mutex 126 */ 127 static void del_nbp(struct net_bridge_port *p) 128 { 129 struct net_bridge *br = p->br; 130 struct net_device *dev = p->dev; 131 132 sysfs_remove_link(br->ifobj, p->dev->name); 133 134 dev_set_promiscuity(dev, -1); 135 136 spin_lock_bh(&br->lock); 137 br_stp_disable_port(p); 138 spin_unlock_bh(&br->lock); 139 140 br_ifinfo_notify(RTM_DELLINK, p); 141 142 br_fdb_delete_by_port(br, p, 1); 143 144 list_del_rcu(&p->list); 145 146 dev->priv_flags &= ~IFF_BRIDGE_PORT; 147 148 netdev_rx_handler_unregister(dev); 149 synchronize_net(); 150 151 netdev_set_master(dev, NULL); 152 153 br_multicast_del_port(p); 154 155 kobject_uevent(&p->kobj, KOBJ_REMOVE); 156 kobject_del(&p->kobj); 157 158 br_netpoll_disable(p); 159 160 call_rcu(&p->rcu, destroy_nbp_rcu); 161 } 162 163 /* Delete bridge device */ 164 void br_dev_delete(struct net_device *dev, struct list_head *head) 165 { 166 struct net_bridge *br = netdev_priv(dev); 167 struct net_bridge_port *p, *n; 168 169 list_for_each_entry_safe(p, n, &br->port_list, list) { 170 del_nbp(p); 171 } 172 173 del_timer_sync(&br->gc_timer); 174 175 br_sysfs_delbr(br->dev); 176 unregister_netdevice_queue(br->dev, head); 177 } 178 179 /* find an available port number */ 180 static int find_portno(struct net_bridge *br) 181 { 182 int index; 183 struct net_bridge_port *p; 184 unsigned long *inuse; 185 186 inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long), 187 GFP_KERNEL); 188 if (!inuse) 189 return -ENOMEM; 190 191 set_bit(0, inuse); /* zero is reserved */ 192 list_for_each_entry(p, &br->port_list, list) { 193 set_bit(p->port_no, inuse); 194 } 195 index = find_first_zero_bit(inuse, BR_MAX_PORTS); 196 kfree(inuse); 197 198 return (index >= BR_MAX_PORTS) ? -EXFULL : index; 199 } 200 201 /* called with RTNL but without bridge lock */ 202 static struct net_bridge_port *new_nbp(struct net_bridge *br, 203 struct net_device *dev) 204 { 205 int index; 206 struct net_bridge_port *p; 207 208 index = find_portno(br); 209 if (index < 0) 210 return ERR_PTR(index); 211 212 p = kzalloc(sizeof(*p), GFP_KERNEL); 213 if (p == NULL) 214 return ERR_PTR(-ENOMEM); 215 216 p->br = br; 217 dev_hold(dev); 218 p->dev = dev; 219 p->path_cost = port_cost(dev); 220 p->priority = 0x8000 >> BR_PORT_BITS; 221 p->port_no = index; 222 p->flags = 0; 223 br_init_port(p); 224 p->state = BR_STATE_DISABLED; 225 br_stp_port_timer_init(p); 226 br_multicast_add_port(p); 227 228 return p; 229 } 230 231 int br_add_bridge(struct net *net, const char *name) 232 { 233 struct net_device *dev; 234 int res; 235 236 dev = alloc_netdev(sizeof(struct net_bridge), name, 237 br_dev_setup); 238 239 if (!dev) 240 return -ENOMEM; 241 242 dev_net_set(dev, net); 243 dev->rtnl_link_ops = &br_link_ops; 244 245 res = register_netdev(dev); 246 if (res) 247 free_netdev(dev); 248 return res; 249 } 250 251 int br_del_bridge(struct net *net, const char *name) 252 { 253 struct net_device *dev; 254 int ret = 0; 255 256 rtnl_lock(); 257 dev = __dev_get_by_name(net, name); 258 if (dev == NULL) 259 ret = -ENXIO; /* Could not find device */ 260 261 else if (!(dev->priv_flags & IFF_EBRIDGE)) { 262 /* Attempt to delete non bridge device! */ 263 ret = -EPERM; 264 } 265 266 else if (dev->flags & IFF_UP) { 267 /* Not shutdown yet. */ 268 ret = -EBUSY; 269 } 270 271 else 272 br_dev_delete(dev, NULL); 273 274 rtnl_unlock(); 275 return ret; 276 } 277 278 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */ 279 int br_min_mtu(const struct net_bridge *br) 280 { 281 const struct net_bridge_port *p; 282 int mtu = 0; 283 284 ASSERT_RTNL(); 285 286 if (list_empty(&br->port_list)) 287 mtu = ETH_DATA_LEN; 288 else { 289 list_for_each_entry(p, &br->port_list, list) { 290 if (!mtu || p->dev->mtu < mtu) 291 mtu = p->dev->mtu; 292 } 293 } 294 return mtu; 295 } 296 297 /* 298 * Recomputes features using slave's features 299 */ 300 netdev_features_t br_features_recompute(struct net_bridge *br, 301 netdev_features_t features) 302 { 303 struct net_bridge_port *p; 304 netdev_features_t mask; 305 306 if (list_empty(&br->port_list)) 307 return features; 308 309 mask = features; 310 features &= ~NETIF_F_ONE_FOR_ALL; 311 312 list_for_each_entry(p, &br->port_list, list) { 313 features = netdev_increment_features(features, 314 p->dev->features, mask); 315 } 316 317 return features; 318 } 319 320 /* called with RTNL */ 321 int br_add_if(struct net_bridge *br, struct net_device *dev) 322 { 323 struct net_bridge_port *p; 324 int err = 0; 325 bool changed_addr; 326 327 /* Don't allow bridging non-ethernet like devices */ 328 if ((dev->flags & IFF_LOOPBACK) || 329 dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN || 330 !is_valid_ether_addr(dev->dev_addr)) 331 return -EINVAL; 332 333 /* No bridging of bridges */ 334 if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) 335 return -ELOOP; 336 337 /* Device is already being bridged */ 338 if (br_port_exists(dev)) 339 return -EBUSY; 340 341 /* No bridging devices that dislike that (e.g. wireless) */ 342 if (dev->priv_flags & IFF_DONT_BRIDGE) 343 return -EOPNOTSUPP; 344 345 p = new_nbp(br, dev); 346 if (IS_ERR(p)) 347 return PTR_ERR(p); 348 349 call_netdevice_notifiers(NETDEV_JOIN, dev); 350 351 err = dev_set_promiscuity(dev, 1); 352 if (err) 353 goto put_back; 354 355 err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj), 356 SYSFS_BRIDGE_PORT_ATTR); 357 if (err) 358 goto err1; 359 360 err = br_sysfs_addif(p); 361 if (err) 362 goto err2; 363 364 if (br_netpoll_info(br) && ((err = br_netpoll_enable(p, GFP_KERNEL)))) 365 goto err3; 366 367 err = netdev_set_master(dev, br->dev); 368 if (err) 369 goto err3; 370 371 err = netdev_rx_handler_register(dev, br_handle_frame, p); 372 if (err) 373 goto err4; 374 375 dev->priv_flags |= IFF_BRIDGE_PORT; 376 377 dev_disable_lro(dev); 378 379 list_add_rcu(&p->list, &br->port_list); 380 381 netdev_update_features(br->dev); 382 383 spin_lock_bh(&br->lock); 384 changed_addr = br_stp_recalculate_bridge_id(br); 385 386 if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) && 387 (br->dev->flags & IFF_UP)) 388 br_stp_enable_port(p); 389 spin_unlock_bh(&br->lock); 390 391 br_ifinfo_notify(RTM_NEWLINK, p); 392 393 if (changed_addr) 394 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev); 395 396 dev_set_mtu(br->dev, br_min_mtu(br)); 397 398 if (br_fdb_insert(br, p, dev->dev_addr)) 399 netdev_err(dev, "failed insert local address bridge forwarding table\n"); 400 401 kobject_uevent(&p->kobj, KOBJ_ADD); 402 403 return 0; 404 405 err4: 406 netdev_set_master(dev, NULL); 407 err3: 408 sysfs_remove_link(br->ifobj, p->dev->name); 409 err2: 410 kobject_put(&p->kobj); 411 p = NULL; /* kobject_put frees */ 412 err1: 413 dev_set_promiscuity(dev, -1); 414 put_back: 415 dev_put(dev); 416 kfree(p); 417 return err; 418 } 419 420 /* called with RTNL */ 421 int br_del_if(struct net_bridge *br, struct net_device *dev) 422 { 423 struct net_bridge_port *p; 424 bool changed_addr; 425 426 p = br_port_get_rtnl(dev); 427 if (!p || p->br != br) 428 return -EINVAL; 429 430 /* Since more than one interface can be attached to a bridge, 431 * there still maybe an alternate path for netconsole to use; 432 * therefore there is no reason for a NETDEV_RELEASE event. 433 */ 434 del_nbp(p); 435 436 spin_lock_bh(&br->lock); 437 changed_addr = br_stp_recalculate_bridge_id(br); 438 spin_unlock_bh(&br->lock); 439 440 if (changed_addr) 441 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev); 442 443 netdev_update_features(br->dev); 444 445 return 0; 446 } 447 448 void __net_exit br_net_exit(struct net *net) 449 { 450 struct net_device *dev; 451 LIST_HEAD(list); 452 453 rtnl_lock(); 454 for_each_netdev(net, dev) 455 if (dev->priv_flags & IFF_EBRIDGE) 456 br_dev_delete(dev, &list); 457 458 unregister_netdevice_many(&list); 459 rtnl_unlock(); 460 461 } 462