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 static void port_carrier_check(void *arg)
  81 {
  82         struct net_bridge_port *p = arg;
  83
  84         rtnl_lock();
  85         if (netif_carrier_ok(p->dev)) {
  86                 u32 cost = port_cost(p->dev);
  87
  88                 spin_lock_bh(&p->br->lock);
  89                 if (p->state == BR_STATE_DISABLED) {
  90                         p->path_cost = cost;
  91                         br_stp_enable_port(p);
  92                 }
  93                 spin_unlock_bh(&p->br->lock);
  94         } else {
  95                 spin_lock_bh(&p->br->lock);
  96                 if (p->state != BR_STATE_DISABLED)
  97                         br_stp_disable_port(p);
  98                 spin_unlock_bh(&p->br->lock);
  99         }
 100         rtnl_unlock();
 101 }
 102
 103 static void destroy_nbp(struct net_bridge_port *p)
 104 {
 105         struct net_device *dev = p->dev;
 106
 107         p->br = NULL;
 108         p->dev = NULL;
 109         dev_put(dev);
 110
 111         br_sysfs_freeif(p);
 112 }
 113
 114 static void destroy_nbp_rcu(struct rcu_head *head)
 115 {
 116         struct net_bridge_port *p =
 117                         container_of(head, struct net_bridge_port, rcu);
 118         destroy_nbp(p);
 119 }
 120
 121 /* called with RTNL */
 122 static void del_nbp(struct net_bridge_port *p)
 123 {
 124         struct net_bridge *br = p->br;
 125         struct net_device *dev = p->dev;
 126
 127         dev->br_port = NULL;
 128         dev_set_promiscuity(dev, -1);
 129
 130         cancel_delayed_work(&p->carrier_check);
 131         flush_scheduled_work();
 132
 133         spin_lock_bh(&br->lock);
 134         br_stp_disable_port(p);
 135         spin_unlock_bh(&br->lock);
 136
 137         br_fdb_delete_by_port(br, p);
 138
 139         list_del_rcu(&p->list);
 140
 141         del_timer_sync(&p->message_age_timer);
 142         del_timer_sync(&p->forward_delay_timer);
 143         del_timer_sync(&p->hold_timer);
 144
 145         call_rcu(&p->rcu, destroy_nbp_rcu);
 146 }
 147
 148 /* called with RTNL */
 149 static void del_br(struct net_bridge *br)
 150 {
 151         struct net_bridge_port *p, *n;
 152
 153         list_for_each_entry_safe(p, n, &br->port_list, list) {
 154                 br_sysfs_removeif(p);
 155                 del_nbp(p);
 156         }
 157
 158         del_timer_sync(&br->gc_timer);
 159
 160         br_sysfs_delbr(br->dev);
 161         unregister_netdevice(br->dev);
 162 }
 163
 164 static struct net_device *new_bridge_dev(const char *name)
 165 {
 166         struct net_bridge *br;
 167         struct net_device *dev;
 168
 169         dev = alloc_netdev(sizeof(struct net_bridge), name,
 170                            br_dev_setup);
 171
 172         if (!dev)
 173                 return NULL;
 174
 175         br = netdev_priv(dev);
 176         br->dev = dev;
 177
 178         spin_lock_init(&br->lock);
 179         INIT_LIST_HEAD(&br->port_list);
 180         spin_lock_init(&br->hash_lock);
 181
 182         br->bridge_id.prio[0] = 0x80;
 183         br->bridge_id.prio[1] = 0x00;
 184         memset(br->bridge_id.addr, 0, ETH_ALEN);
 185
 186         br->feature_mask = dev->features;
 187         br->stp_enabled = 0;
 188         br->designated_root = br->bridge_id;
 189         br->root_path_cost = 0;
 190         br->root_port = 0;
 191         br->bridge_max_age = br->max_age = 20 * HZ;
 192         br->bridge_hello_time = br->hello_time = 2 * HZ;
 193         br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 194         br->topology_change = 0;
 195         br->topology_change_detected = 0;
 196         br->ageing_time = 300 * HZ;
 197         INIT_LIST_HEAD(&br->age_list);
 198
 199         br_stp_timer_init(br);
 200
 201         return dev;
 202 }
 203
 204 /* find an available port number */
 205 static int find_portno(struct net_bridge *br)
 206 {
 207         int index;
 208         struct net_bridge_port *p;
 209         unsigned long *inuse;
 210
 211         inuse = kmalloc(BITS_TO_LONGS(BR_MAX_PORTS)*sizeof(unsigned long),
 212                         GFP_KERNEL);
 213         if (!inuse)
 214                 return -ENOMEM;
 215
 216         memset(inuse, 0, BITS_TO_LONGS(BR_MAX_PORTS)*sizeof(unsigned long));
 217         set_bit(0, inuse);      /* zero is reserved */
 218         list_for_each_entry(p, &br->port_list, list) {
 219                 set_bit(p->port_no, inuse);
 220         }
 221         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 222         kfree(inuse);
 223
 224         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 225 }
 226
 227 /* called with RTNL but without bridge lock */
 228 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 229                                        struct net_device *dev)
 230 {
 231         int index;
 232         struct net_bridge_port *p;
 233
 234         index = find_portno(br);
 235         if (index < 0)
 236                 return ERR_PTR(index);
 237
 238         p = kmalloc(sizeof(*p), GFP_KERNEL);
 239         if (p == NULL)
 240                 return ERR_PTR(-ENOMEM);
 241
 242         memset(p, 0, sizeof(*p));
 243         p->br = br;
 244         dev_hold(dev);
 245         p->dev = dev;
 246         p->path_cost = port_cost(dev);
 247         p->priority = 0x8000 >> BR_PORT_BITS;
 248         dev->br_port = p;
 249         p->port_no = index;
 250         br_init_port(p);
 251         p->state = BR_STATE_DISABLED;
 252         INIT_WORK(&p->carrier_check, port_carrier_check, p);
 253         kobject_init(&p->kobj);
 254
 255         return p;
 256 }
 257
 258 int br_add_bridge(const char *name)
 259 {
 260         struct net_device *dev;
 261         int ret;
 262
 263         dev = new_bridge_dev(name);
 264         if (!dev)
 265                 return -ENOMEM;
 266
 267         rtnl_lock();
 268         if (strchr(dev->name, '%')) {
 269                 ret = dev_alloc_name(dev, dev->name);
 270                 if (ret < 0)
 271                         goto err1;
 272         }
 273
 274         ret = register_netdevice(dev);
 275         if (ret)
 276                 goto err2;
 277
 278         /* network device kobject is not setup until
 279          * after rtnl_unlock does it's hotplug magic.
 280          * so hold reference to avoid race.
 281          */
 282         dev_hold(dev);
 283         rtnl_unlock();
 284
 285         ret = br_sysfs_addbr(dev);
 286         dev_put(dev);
 287
 288         if (ret)
 289                 unregister_netdev(dev);
 290  out:
 291         return ret;
 292
 293  err2:
 294         free_netdev(dev);
 295  err1:
 296         rtnl_unlock();
 297         goto out;
 298 }
 299
 300 int br_del_bridge(const char *name)
 301 {
 302         struct net_device *dev;
 303         int ret = 0;
 304
 305         rtnl_lock();
 306         dev = __dev_get_by_name(name);
 307         if (dev == NULL)
 308                 ret =  -ENXIO;  /* Could not find device */
 309
 310         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 311                 /* Attempt to delete non bridge device! */
 312                 ret = -EPERM;
 313         }
 314
 315         else if (dev->flags & IFF_UP) {
 316                 /* Not shutdown yet. */
 317                 ret = -EBUSY;
 318         }
 319
 320         else
 321                 del_br(netdev_priv(dev));
 322
 323         rtnl_unlock();
 324         return ret;
 325 }
 326
 327 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 328 int br_min_mtu(const struct net_bridge *br)
 329 {
 330         const struct net_bridge_port *p;
 331         int mtu = 0;
 332
 333         ASSERT_RTNL();
 334
 335         if (list_empty(&br->port_list))
 336                 mtu = ETH_DATA_LEN;
 337         else {
 338                 list_for_each_entry(p, &br->port_list, list) {
 339                         if (!mtu  || p->dev->mtu < mtu)
 340                                 mtu = p->dev->mtu;
 341                 }
 342         }
 343         return mtu;
 344 }
 345
 346 /*
 347  * Recomputes features using slave's features
 348  */
 349 void br_features_recompute(struct net_bridge *br)
 350 {
 351         struct net_bridge_port *p;
 352         unsigned long features, checksum;
 353
 354         features = br->feature_mask &~ NETIF_F_IP_CSUM;
 355         checksum = br->feature_mask & NETIF_F_IP_CSUM;
 356
 357         list_for_each_entry(p, &br->port_list, list) {
 358                 if (!(p->dev->features
 359                       & (NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM)))
 360                         checksum = 0;
 361                 features &= p->dev->features;
 362         }
 363
 364         br->dev->features = features | checksum | NETIF_F_LLTX;
 365 }
 366
 367 /* called with RTNL */
 368 int br_add_if(struct net_bridge *br, struct net_device *dev)
 369 {
 370         struct net_bridge_port *p;
 371         int err = 0;
 372
 373         if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
 374                 return -EINVAL;
 375
 376         if (dev->hard_start_xmit == br_dev_xmit)
 377                 return -ELOOP;
 378
 379         if (dev->br_port != NULL)
 380                 return -EBUSY;
 381
 382         if (IS_ERR(p = new_nbp(br, dev)))
 383                 return PTR_ERR(p);
 384
 385         if ((err = br_fdb_insert(br, p, dev->dev_addr)))
 386                 destroy_nbp(p);
 387
 388         else if ((err = br_sysfs_addif(p)))
 389                 del_nbp(p);
 390         else {
 391                 dev_set_promiscuity(dev, 1);
 392
 393                 list_add_rcu(&p->list, &br->port_list);
 394
 395                 spin_lock_bh(&br->lock);
 396                 br_stp_recalculate_bridge_id(br);
 397                 br_features_recompute(br);
 398                 if ((br->dev->flags & IFF_UP)
 399                     && (dev->flags & IFF_UP) && netif_carrier_ok(dev))
 400                         br_stp_enable_port(p);
 401                 spin_unlock_bh(&br->lock);
 402
 403                 dev_set_mtu(br->dev, br_min_mtu(br));
 404         }
 405
 406         return err;
 407 }
 408
 409 /* called with RTNL */
 410 int br_del_if(struct net_bridge *br, struct net_device *dev)
 411 {
 412         struct net_bridge_port *p = dev->br_port;
 413
 414         if (!p || p->br != br)
 415                 return -EINVAL;
 416
 417         br_sysfs_removeif(p);
 418         del_nbp(p);
 419
 420         spin_lock_bh(&br->lock);
 421         br_stp_recalculate_bridge_id(br);
 422         br_features_recompute(br);
 423         spin_unlock_bh(&br->lock);
 424
 425         return 0;
 426 }
 427
 428 void __exit br_cleanup_bridges(void)
 429 {
 430         struct net_device *dev, *nxt;
 431
 432         rtnl_lock();
 433         for (dev = dev_base; dev; dev = nxt) {
 434                 nxt = dev->next;
 435                 if (dev->priv_flags & IFF_EBRIDGE)
 436                         del_br(dev->priv);
 437         }
 438         rtnl_unlock();
 439
 440 }