net/bridge/br_if.c

   1 /*
   2  *      Userspace interface
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      $Id: br_if.c,v 1.7 2001/12/24 00:59:55 davem Exp $
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/netdevice.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 <net/sock.h>
  25
  26 #include "br_private.h"
  27
  28 /*
  29  * Determine initial path cost based on speed.
  30  * using recommendations from 802.1d standard
  31  *
  32  * Need to simulate user ioctl because not all device's that support
  33  * ethtool, use ethtool_ops.  Also, since driver might sleep need to
  34  * not be holding any locks.
  35  */
  36 static int port_cost(struct net_device *dev)
  37 {
  38         struct ethtool_cmd ecmd = { ETHTOOL_GSET };
  39         struct ifreq ifr;
  40         mm_segment_t old_fs;
  41         int err;
  42
  43         strncpy(ifr.ifr_name, dev->name, IFNAMSIZ);
  44         ifr.ifr_data = (void __user *) &ecmd;
  45
  46         old_fs = get_fs();
  47         set_fs(KERNEL_DS);
  48         err = dev_ethtool(&ifr);
  49         set_fs(old_fs);
  50
  51         if (!err) {
  52                 switch(ecmd.speed) {
  53                 case SPEED_100:
  54                         return 19;
  55                 case SPEED_1000:
  56                         return 4;
  57                 case SPEED_10000:
  58                         return 2;
  59                 case SPEED_10:
  60                         return 100;
  61                 }
  62         }
  63
  64         /* Old silly heuristics based on name */
  65         if (!strncmp(dev->name, "lec", 3))
  66                 return 7;
  67
  68         if (!strncmp(dev->name, "plip", 4))
  69                 return 2500;
  70
  71         return 100;     /* assume old 10Mbps */
  72 }
  73
  74
  75 /*
  76  * Check for port carrier transistions.
  77  * Called from work queue to allow for calling functions that
  78  * might sleep (such as speed check), and to debounce.
  79  */
  80 void br_port_carrier_check(struct net_bridge_port *p)
  81 {
  82         struct net_device *dev = p->dev;
  83         struct net_bridge *br = p->br;
  84
  85         if (netif_carrier_ok(dev))
  86                 p->path_cost = port_cost(dev);
  87
  88         if (netif_running(br->dev)) {
  89                 spin_lock_bh(&br->lock);
  90                 if (netif_carrier_ok(dev)) {
  91                         if (p->state == BR_STATE_DISABLED)
  92                                 br_stp_enable_port(p);
  93                 } else {
  94                         if (p->state != BR_STATE_DISABLED)
  95                                 br_stp_disable_port(p);
  96                 }
  97                 spin_unlock_bh(&br->lock);
  98         }
  99 }
 100
 101 static void release_nbp(struct kobject *kobj)
 102 {
 103         struct net_bridge_port *p
 104                 = container_of(kobj, struct net_bridge_port, kobj);
 105         kfree(p);
 106 }
 107
 108 static struct kobj_type brport_ktype = {
 109 #ifdef CONFIG_SYSFS
 110         .sysfs_ops = &brport_sysfs_ops,
 111 #endif
 112         .release = release_nbp,
 113 };
 114
 115 static void destroy_nbp(struct net_bridge_port *p)
 116 {
 117         struct net_device *dev = p->dev;
 118
 119         p->br = NULL;
 120         p->dev = NULL;
 121         dev_put(dev);
 122
 123         kobject_put(&p->kobj);
 124 }
 125
 126 static void destroy_nbp_rcu(struct rcu_head *head)
 127 {
 128         struct net_bridge_port *p =
 129                         container_of(head, struct net_bridge_port, rcu);
 130         destroy_nbp(p);
 131 }
 132
 133 /* Delete port(interface) from bridge is done in two steps.
 134  * via RCU. First step, marks device as down. That deletes
 135  * all the timers and stops new packets from flowing through.
 136  *
 137  * Final cleanup doesn't occur until after all CPU's finished
 138  * processing packets.
 139  *
 140  * Protected from multiple admin operations by RTNL mutex
 141  */
 142 static void del_nbp(struct net_bridge_port *p)
 143 {
 144         struct net_bridge *br = p->br;
 145         struct net_device *dev = p->dev;
 146
 147         sysfs_remove_link(&br->ifobj, dev->name);
 148
 149         dev_set_promiscuity(dev, -1);
 150
 151         spin_lock_bh(&br->lock);
 152         br_stp_disable_port(p);
 153         spin_unlock_bh(&br->lock);
 154
 155         br_fdb_delete_by_port(br, p, 1);
 156
 157         list_del_rcu(&p->list);
 158
 159         rcu_assign_pointer(dev->br_port, NULL);
 160
 161         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 162         kobject_del(&p->kobj);
 163
 164         call_rcu(&p->rcu, destroy_nbp_rcu);
 165 }
 166
 167 /* called with RTNL */
 168 static void del_br(struct net_bridge *br)
 169 {
 170         struct net_bridge_port *p, *n;
 171
 172         list_for_each_entry_safe(p, n, &br->port_list, list) {
 173                 del_nbp(p);
 174         }
 175
 176         del_timer_sync(&br->gc_timer);
 177
 178         br_sysfs_delbr(br->dev);
 179         unregister_netdevice(br->dev);
 180 }
 181
 182 static struct net_device *new_bridge_dev(const char *name)
 183 {
 184         struct net_bridge *br;
 185         struct net_device *dev;
 186
 187         dev = alloc_netdev(sizeof(struct net_bridge), name,
 188                            br_dev_setup);
 189
 190         if (!dev)
 191                 return NULL;
 192
 193         br = netdev_priv(dev);
 194         br->dev = dev;
 195
 196         spin_lock_init(&br->lock);
 197         INIT_LIST_HEAD(&br->port_list);
 198         spin_lock_init(&br->hash_lock);
 199
 200         br->bridge_id.prio[0] = 0x80;
 201         br->bridge_id.prio[1] = 0x00;
 202
 203         memcpy(br->group_addr, br_group_address, ETH_ALEN);
 204
 205         br->feature_mask = dev->features;
 206         br->stp_enabled = 0;
 207         br->designated_root = br->bridge_id;
 208         br->root_path_cost = 0;
 209         br->root_port = 0;
 210         br->bridge_max_age = br->max_age = 20 * HZ;
 211         br->bridge_hello_time = br->hello_time = 2 * HZ;
 212         br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 213         br->topology_change = 0;
 214         br->topology_change_detected = 0;
 215         br->ageing_time = 300 * HZ;
 216         INIT_LIST_HEAD(&br->age_list);
 217
 218         br_stp_timer_init(br);
 219
 220         return dev;
 221 }
 222
 223 /* find an available port number */
 224 static int find_portno(struct net_bridge *br)
 225 {
 226         int index;
 227         struct net_bridge_port *p;
 228         unsigned long *inuse;
 229
 230         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 231                         GFP_KERNEL);
 232         if (!inuse)
 233                 return -ENOMEM;
 234
 235         set_bit(0, inuse);      /* zero is reserved */
 236         list_for_each_entry(p, &br->port_list, list) {
 237                 set_bit(p->port_no, inuse);
 238         }
 239         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 240         kfree(inuse);
 241
 242         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 243 }
 244
 245 /* called with RTNL but without bridge lock */
 246 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 247                                        struct net_device *dev)
 248 {
 249         int index;
 250         struct net_bridge_port *p;
 251
 252         index = find_portno(br);
 253         if (index < 0)
 254                 return ERR_PTR(index);
 255
 256         p = kzalloc(sizeof(*p), GFP_KERNEL);
 257         if (p == NULL)
 258                 return ERR_PTR(-ENOMEM);
 259
 260         p->br = br;
 261         dev_hold(dev);
 262         p->dev = dev;
 263         p->path_cost = port_cost(dev);
 264         p->priority = 0x8000 >> BR_PORT_BITS;
 265         p->port_no = index;
 266         br_init_port(p);
 267         p->state = BR_STATE_DISABLED;
 268         br_stp_port_timer_init(p);
 269
 270         kobject_init(&p->kobj);
 271         kobject_set_name(&p->kobj, SYSFS_BRIDGE_PORT_ATTR);
 272         p->kobj.ktype = &brport_ktype;
 273         p->kobj.parent = &(dev->dev.kobj);
 274         p->kobj.kset = NULL;
 275
 276         return p;
 277 }
 278
 279 int br_add_bridge(const char *name)
 280 {
 281         struct net_device *dev;
 282         int ret;
 283
 284         dev = new_bridge_dev(name);
 285         if (!dev)
 286                 return -ENOMEM;
 287
 288         rtnl_lock();
 289         if (strchr(dev->name, '%')) {
 290                 ret = dev_alloc_name(dev, dev->name);
 291                 if (ret < 0) {
 292                         free_netdev(dev);
 293                         goto out;
 294                 }
 295         }
 296
 297         ret = register_netdevice(dev);
 298         if (ret)
 299                 goto out;
 300
 301         ret = br_sysfs_addbr(dev);
 302         if (ret)
 303                 unregister_netdevice(dev);
 304  out:
 305         rtnl_unlock();
 306         return ret;
 307 }
 308
 309 int br_del_bridge(const char *name)
 310 {
 311         struct net_device *dev;
 312         int ret = 0;
 313
 314         rtnl_lock();
 315         dev = __dev_get_by_name(name);
 316         if (dev == NULL)
 317                 ret =  -ENXIO;  /* Could not find device */
 318
 319         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 320                 /* Attempt to delete non bridge device! */
 321                 ret = -EPERM;
 322         }
 323
 324         else if (dev->flags & IFF_UP) {
 325                 /* Not shutdown yet. */
 326                 ret = -EBUSY;
 327         }
 328
 329         else
 330                 del_br(netdev_priv(dev));
 331
 332         rtnl_unlock();
 333         return ret;
 334 }
 335
 336 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 337 int br_min_mtu(const struct net_bridge *br)
 338 {
 339         const struct net_bridge_port *p;
 340         int mtu = 0;
 341
 342         ASSERT_RTNL();
 343
 344         if (list_empty(&br->port_list))
 345                 mtu = ETH_DATA_LEN;
 346         else {
 347                 list_for_each_entry(p, &br->port_list, list) {
 348                         if (!mtu  || p->dev->mtu < mtu)
 349                                 mtu = p->dev->mtu;
 350                 }
 351         }
 352         return mtu;
 353 }
 354
 355 /*
 356  * Recomputes features using slave's features
 357  */
 358 void br_features_recompute(struct net_bridge *br)
 359 {
 360         struct net_bridge_port *p;
 361         unsigned long features, checksum;
 362
 363         checksum = br->feature_mask & NETIF_F_ALL_CSUM ? NETIF_F_NO_CSUM : 0;
 364         features = br->feature_mask & ~NETIF_F_ALL_CSUM;
 365
 366         list_for_each_entry(p, &br->port_list, list) {
 367                 unsigned long feature = p->dev->features;
 368
 369                 if (checksum & NETIF_F_NO_CSUM && !(feature & NETIF_F_NO_CSUM))
 370                         checksum ^= NETIF_F_NO_CSUM | NETIF_F_HW_CSUM;
 371                 if (checksum & NETIF_F_HW_CSUM && !(feature & NETIF_F_HW_CSUM))
 372                         checksum ^= NETIF_F_HW_CSUM | NETIF_F_IP_CSUM;
 373                 if (!(feature & NETIF_F_IP_CSUM))
 374                         checksum = 0;
 375
 376                 if (feature & NETIF_F_GSO)
 377                         feature |= NETIF_F_GSO_SOFTWARE;
 378                 feature |= NETIF_F_GSO;
 379
 380                 features &= feature;
 381         }
 382
 383         if (!(checksum & NETIF_F_ALL_CSUM))
 384                 features &= ~NETIF_F_SG;
 385         if (!(features & NETIF_F_SG))
 386                 features &= ~NETIF_F_GSO_MASK;
 387
 388         br->dev->features = features | checksum | NETIF_F_LLTX |
 389                             NETIF_F_GSO_ROBUST;
 390 }
 391
 392 /* called with RTNL */
 393 int br_add_if(struct net_bridge *br, struct net_device *dev)
 394 {
 395         struct net_bridge_port *p;
 396         int err = 0;
 397
 398         if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
 399                 return -EINVAL;
 400
 401         if (dev->hard_start_xmit == br_dev_xmit)
 402                 return -ELOOP;
 403
 404         if (dev->br_port != NULL)
 405                 return -EBUSY;
 406
 407         p = new_nbp(br, dev);
 408         if (IS_ERR(p))
 409                 return PTR_ERR(p);
 410
 411         err = kobject_add(&p->kobj);
 412         if (err)
 413                 goto err0;
 414
 415         err = br_fdb_insert(br, p, dev->dev_addr);
 416         if (err)
 417                 goto err1;
 418
 419         err = br_sysfs_addif(p);
 420         if (err)
 421                 goto err2;
 422
 423         rcu_assign_pointer(dev->br_port, p);
 424         dev_set_promiscuity(dev, 1);
 425
 426         list_add_rcu(&p->list, &br->port_list);
 427
 428         spin_lock_bh(&br->lock);
 429         br_stp_recalculate_bridge_id(br);
 430         br_features_recompute(br);
 431
 432         if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
 433             (br->dev->flags & IFF_UP))
 434                 br_stp_enable_port(p);
 435         spin_unlock_bh(&br->lock);
 436
 437         dev_set_mtu(br->dev, br_min_mtu(br));
 438
 439         kobject_uevent(&p->kobj, KOBJ_ADD);
 440
 441         return 0;
 442 err2:
 443         br_fdb_delete_by_port(br, p, 1);
 444 err1:
 445         kobject_del(&p->kobj);
 446 err0:
 447         kobject_put(&p->kobj);
 448         return err;
 449 }
 450
 451 /* called with RTNL */
 452 int br_del_if(struct net_bridge *br, struct net_device *dev)
 453 {
 454         struct net_bridge_port *p = dev->br_port;
 455
 456         if (!p || p->br != br)
 457                 return -EINVAL;
 458
 459         del_nbp(p);
 460
 461         spin_lock_bh(&br->lock);
 462         br_stp_recalculate_bridge_id(br);
 463         br_features_recompute(br);
 464         spin_unlock_bh(&br->lock);
 465
 466         return 0;
 467 }
 468
 469 void __exit br_cleanup_bridges(void)
 470 {
 471         struct net_device *dev, *nxt;
 472
 473         rtnl_lock();
 474         for (dev = dev_base; dev; dev = nxt) {
 475                 nxt = dev->next;
 476                 if (dev->priv_flags & IFF_EBRIDGE)
 477                         del_br(dev->priv);
 478         }
 479         rtnl_unlock();
 480
 481 }