drivers/net/net_failover.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2018, Intel Corporation. */
   3
   4 /* This provides a net_failover interface for paravirtual drivers to
   5  * provide an alternate datapath by exporting APIs to create and
   6  * destroy a upper 'net_failover' netdev. The upper dev manages the
   7  * original paravirtual interface as a 'standby' netdev and uses the
   8  * generic failover infrastructure to register and manage a direct
   9  * attached VF as a 'primary' netdev. This enables live migration of
  10  * a VM with direct attached VF by failing over to the paravirtual
  11  * datapath when the VF is unplugged.
  12  *
  13  * Some of the netdev management routines are based on bond/team driver as
  14  * this driver provides active-backup functionality similar to those drivers.
  15  */
  16
  17 #include <linux/netdevice.h>
  18 #include <linux/etherdevice.h>
  19 #include <linux/ethtool.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/netpoll.h>
  24 #include <linux/rtnetlink.h>
  25 #include <linux/if_vlan.h>
  26 #include <linux/pci.h>
  27 #include <net/sch_generic.h>
  28 #include <uapi/linux/if_arp.h>
  29 #include <net/net_failover.h>
  30
  31 static bool net_failover_xmit_ready(struct net_device *dev)
  32 {
  33         return netif_running(dev) && netif_carrier_ok(dev);
  34 }
  35
  36 static int net_failover_open(struct net_device *dev)
  37 {
  38         struct net_failover_info *nfo_info = netdev_priv(dev);
  39         struct net_device *primary_dev, *standby_dev;
  40         int err;
  41
  42         primary_dev = rtnl_dereference(nfo_info->primary_dev);
  43         if (primary_dev) {
  44                 err = dev_open(primary_dev);
  45                 if (err)
  46                         goto err_primary_open;
  47         }
  48
  49         standby_dev = rtnl_dereference(nfo_info->standby_dev);
  50         if (standby_dev) {
  51                 err = dev_open(standby_dev);
  52                 if (err)
  53                         goto err_standby_open;
  54         }
  55
  56         if ((primary_dev && net_failover_xmit_ready(primary_dev)) ||
  57             (standby_dev && net_failover_xmit_ready(standby_dev))) {
  58                 netif_carrier_on(dev);
  59                 netif_tx_wake_all_queues(dev);
  60         }
  61
  62         return 0;
  63
  64 err_standby_open:
  65         dev_close(primary_dev);
  66 err_primary_open:
  67         netif_tx_disable(dev);
  68         return err;
  69 }
  70
  71 static int net_failover_close(struct net_device *dev)
  72 {
  73         struct net_failover_info *nfo_info = netdev_priv(dev);
  74         struct net_device *slave_dev;
  75
  76         netif_tx_disable(dev);
  77
  78         slave_dev = rtnl_dereference(nfo_info->primary_dev);
  79         if (slave_dev)
  80                 dev_close(slave_dev);
  81
  82         slave_dev = rtnl_dereference(nfo_info->standby_dev);
  83         if (slave_dev)
  84                 dev_close(slave_dev);
  85
  86         return 0;
  87 }
  88
  89 static netdev_tx_t net_failover_drop_xmit(struct sk_buff *skb,
  90                                           struct net_device *dev)
  91 {
  92         atomic_long_inc(&dev->tx_dropped);
  93         dev_kfree_skb_any(skb);
  94         return NETDEV_TX_OK;
  95 }
  96
  97 static netdev_tx_t net_failover_start_xmit(struct sk_buff *skb,
  98                                            struct net_device *dev)
  99 {
 100         struct net_failover_info *nfo_info = netdev_priv(dev);
 101         struct net_device *xmit_dev;
 102
 103         /* Try xmit via primary netdev followed by standby netdev */
 104         xmit_dev = rcu_dereference_bh(nfo_info->primary_dev);
 105         if (!xmit_dev || !net_failover_xmit_ready(xmit_dev)) {
 106                 xmit_dev = rcu_dereference_bh(nfo_info->standby_dev);
 107                 if (!xmit_dev || !net_failover_xmit_ready(xmit_dev))
 108                         return net_failover_drop_xmit(skb, dev);
 109         }
 110
 111         skb->dev = xmit_dev;
 112         skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping;
 113
 114         return dev_queue_xmit(skb);
 115 }
 116
 117 static u16 net_failover_select_queue(struct net_device *dev,
 118                                      struct sk_buff *skb,
 119                                      struct net_device *sb_dev,
 120                                      select_queue_fallback_t fallback)
 121 {
 122         struct net_failover_info *nfo_info = netdev_priv(dev);
 123         struct net_device *primary_dev;
 124         u16 txq;
 125
 126         primary_dev = rcu_dereference(nfo_info->primary_dev);
 127         if (primary_dev) {
 128                 const struct net_device_ops *ops = primary_dev->netdev_ops;
 129
 130                 if (ops->ndo_select_queue)
 131                         txq = ops->ndo_select_queue(primary_dev, skb,
 132                                                     sb_dev, fallback);
 133                 else
 134                         txq = fallback(primary_dev, skb, NULL);
 135
 136                 qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
 137
 138                 return txq;
 139         }
 140
 141         txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0;
 142
 143         /* Save the original txq to restore before passing to the driver */
 144         qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
 145
 146         if (unlikely(txq >= dev->real_num_tx_queues)) {
 147                 do {
 148                         txq -= dev->real_num_tx_queues;
 149                 } while (txq >= dev->real_num_tx_queues);
 150         }
 151
 152         return txq;
 153 }
 154
 155 /* fold stats, assuming all rtnl_link_stats64 fields are u64, but
 156  * that some drivers can provide 32bit values only.
 157  */
 158 static void net_failover_fold_stats(struct rtnl_link_stats64 *_res,
 159                                     const struct rtnl_link_stats64 *_new,
 160                                     const struct rtnl_link_stats64 *_old)
 161 {
 162         const u64 *new = (const u64 *)_new;
 163         const u64 *old = (const u64 *)_old;
 164         u64 *res = (u64 *)_res;
 165         int i;
 166
 167         for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) {
 168                 u64 nv = new[i];
 169                 u64 ov = old[i];
 170                 s64 delta = nv - ov;
 171
 172                 /* detects if this particular field is 32bit only */
 173                 if (((nv | ov) >> 32) == 0)
 174                         delta = (s64)(s32)((u32)nv - (u32)ov);
 175
 176                 /* filter anomalies, some drivers reset their stats
 177                  * at down/up events.
 178                  */
 179                 if (delta > 0)
 180                         res[i] += delta;
 181         }
 182 }
 183
 184 static void net_failover_get_stats(struct net_device *dev,
 185                                    struct rtnl_link_stats64 *stats)
 186 {
 187         struct net_failover_info *nfo_info = netdev_priv(dev);
 188         const struct rtnl_link_stats64 *new;
 189         struct rtnl_link_stats64 temp;
 190         struct net_device *slave_dev;
 191
 192         spin_lock(&nfo_info->stats_lock);
 193         memcpy(stats, &nfo_info->failover_stats, sizeof(*stats));
 194
 195         rcu_read_lock();
 196
 197         slave_dev = rcu_dereference(nfo_info->primary_dev);
 198         if (slave_dev) {
 199                 new = dev_get_stats(slave_dev, &temp);
 200                 net_failover_fold_stats(stats, new, &nfo_info->primary_stats);
 201                 memcpy(&nfo_info->primary_stats, new, sizeof(*new));
 202         }
 203
 204         slave_dev = rcu_dereference(nfo_info->standby_dev);
 205         if (slave_dev) {
 206                 new = dev_get_stats(slave_dev, &temp);
 207                 net_failover_fold_stats(stats, new, &nfo_info->standby_stats);
 208                 memcpy(&nfo_info->standby_stats, new, sizeof(*new));
 209         }
 210
 211         rcu_read_unlock();
 212
 213         memcpy(&nfo_info->failover_stats, stats, sizeof(*stats));
 214         spin_unlock(&nfo_info->stats_lock);
 215 }
 216
 217 static int net_failover_change_mtu(struct net_device *dev, int new_mtu)
 218 {
 219         struct net_failover_info *nfo_info = netdev_priv(dev);
 220         struct net_device *primary_dev, *standby_dev;
 221         int ret = 0;
 222
 223         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 224         if (primary_dev) {
 225                 ret = dev_set_mtu(primary_dev, new_mtu);
 226                 if (ret)
 227                         return ret;
 228         }
 229
 230         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 231         if (standby_dev) {
 232                 ret = dev_set_mtu(standby_dev, new_mtu);
 233                 if (ret) {
 234                         if (primary_dev)
 235                                 dev_set_mtu(primary_dev, dev->mtu);
 236                         return ret;
 237                 }
 238         }
 239
 240         dev->mtu = new_mtu;
 241
 242         return 0;
 243 }
 244
 245 static void net_failover_set_rx_mode(struct net_device *dev)
 246 {
 247         struct net_failover_info *nfo_info = netdev_priv(dev);
 248         struct net_device *slave_dev;
 249
 250         rcu_read_lock();
 251
 252         slave_dev = rcu_dereference(nfo_info->primary_dev);
 253         if (slave_dev) {
 254                 dev_uc_sync_multiple(slave_dev, dev);
 255                 dev_mc_sync_multiple(slave_dev, dev);
 256         }
 257
 258         slave_dev = rcu_dereference(nfo_info->standby_dev);
 259         if (slave_dev) {
 260                 dev_uc_sync_multiple(slave_dev, dev);
 261                 dev_mc_sync_multiple(slave_dev, dev);
 262         }
 263
 264         rcu_read_unlock();
 265 }
 266
 267 static int net_failover_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 268                                         u16 vid)
 269 {
 270         struct net_failover_info *nfo_info = netdev_priv(dev);
 271         struct net_device *primary_dev, *standby_dev;
 272         int ret = 0;
 273
 274         primary_dev = rcu_dereference(nfo_info->primary_dev);
 275         if (primary_dev) {
 276                 ret = vlan_vid_add(primary_dev, proto, vid);
 277                 if (ret)
 278                         return ret;
 279         }
 280
 281         standby_dev = rcu_dereference(nfo_info->standby_dev);
 282         if (standby_dev) {
 283                 ret = vlan_vid_add(standby_dev, proto, vid);
 284                 if (ret)
 285                         if (primary_dev)
 286                                 vlan_vid_del(primary_dev, proto, vid);
 287         }
 288
 289         return ret;
 290 }
 291
 292 static int net_failover_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
 293                                          u16 vid)
 294 {
 295         struct net_failover_info *nfo_info = netdev_priv(dev);
 296         struct net_device *slave_dev;
 297
 298         slave_dev = rcu_dereference(nfo_info->primary_dev);
 299         if (slave_dev)
 300                 vlan_vid_del(slave_dev, proto, vid);
 301
 302         slave_dev = rcu_dereference(nfo_info->standby_dev);
 303         if (slave_dev)
 304                 vlan_vid_del(slave_dev, proto, vid);
 305
 306         return 0;
 307 }
 308
 309 static const struct net_device_ops failover_dev_ops = {
 310         .ndo_open               = net_failover_open,
 311         .ndo_stop               = net_failover_close,
 312         .ndo_start_xmit         = net_failover_start_xmit,
 313         .ndo_select_queue       = net_failover_select_queue,
 314         .ndo_get_stats64        = net_failover_get_stats,
 315         .ndo_change_mtu         = net_failover_change_mtu,
 316         .ndo_set_rx_mode        = net_failover_set_rx_mode,
 317         .ndo_vlan_rx_add_vid    = net_failover_vlan_rx_add_vid,
 318         .ndo_vlan_rx_kill_vid   = net_failover_vlan_rx_kill_vid,
 319         .ndo_validate_addr      = eth_validate_addr,
 320         .ndo_features_check     = passthru_features_check,
 321 };
 322
 323 #define FAILOVER_NAME "net_failover"
 324 #define FAILOVER_VERSION "0.1"
 325
 326 static void nfo_ethtool_get_drvinfo(struct net_device *dev,
 327                                     struct ethtool_drvinfo *drvinfo)
 328 {
 329         strlcpy(drvinfo->driver, FAILOVER_NAME, sizeof(drvinfo->driver));
 330         strlcpy(drvinfo->version, FAILOVER_VERSION, sizeof(drvinfo->version));
 331 }
 332
 333 static int nfo_ethtool_get_link_ksettings(struct net_device *dev,
 334                                           struct ethtool_link_ksettings *cmd)
 335 {
 336         struct net_failover_info *nfo_info = netdev_priv(dev);
 337         struct net_device *slave_dev;
 338
 339         slave_dev = rtnl_dereference(nfo_info->primary_dev);
 340         if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
 341                 slave_dev = rtnl_dereference(nfo_info->standby_dev);
 342                 if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
 343                         cmd->base.duplex = DUPLEX_UNKNOWN;
 344                         cmd->base.port = PORT_OTHER;
 345                         cmd->base.speed = SPEED_UNKNOWN;
 346
 347                         return 0;
 348                 }
 349         }
 350
 351         return __ethtool_get_link_ksettings(slave_dev, cmd);
 352 }
 353
 354 static const struct ethtool_ops failover_ethtool_ops = {
 355         .get_drvinfo            = nfo_ethtool_get_drvinfo,
 356         .get_link               = ethtool_op_get_link,
 357         .get_link_ksettings     = nfo_ethtool_get_link_ksettings,
 358 };
 359
 360 /* Called when slave dev is injecting data into network stack.
 361  * Change the associated network device from lower dev to failover dev.
 362  * note: already called with rcu_read_lock
 363  */
 364 static rx_handler_result_t net_failover_handle_frame(struct sk_buff **pskb)
 365 {
 366         struct sk_buff *skb = *pskb;
 367         struct net_device *dev = rcu_dereference(skb->dev->rx_handler_data);
 368         struct net_failover_info *nfo_info = netdev_priv(dev);
 369         struct net_device *primary_dev, *standby_dev;
 370
 371         primary_dev = rcu_dereference(nfo_info->primary_dev);
 372         standby_dev = rcu_dereference(nfo_info->standby_dev);
 373
 374         if (primary_dev && skb->dev == standby_dev)
 375                 return RX_HANDLER_EXACT;
 376
 377         skb->dev = dev;
 378
 379         return RX_HANDLER_ANOTHER;
 380 }
 381
 382 static void net_failover_compute_features(struct net_device *dev)
 383 {
 384         netdev_features_t vlan_features = FAILOVER_VLAN_FEATURES &
 385                                           NETIF_F_ALL_FOR_ALL;
 386         netdev_features_t enc_features  = FAILOVER_ENC_FEATURES;
 387         unsigned short max_hard_header_len = ETH_HLEN;
 388         unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
 389                                         IFF_XMIT_DST_RELEASE_PERM;
 390         struct net_failover_info *nfo_info = netdev_priv(dev);
 391         struct net_device *primary_dev, *standby_dev;
 392
 393         primary_dev = rcu_dereference(nfo_info->primary_dev);
 394         if (primary_dev) {
 395                 vlan_features =
 396                         netdev_increment_features(vlan_features,
 397                                                   primary_dev->vlan_features,
 398                                                   FAILOVER_VLAN_FEATURES);
 399                 enc_features =
 400                         netdev_increment_features(enc_features,
 401                                                   primary_dev->hw_enc_features,
 402                                                   FAILOVER_ENC_FEATURES);
 403
 404                 dst_release_flag &= primary_dev->priv_flags;
 405                 if (primary_dev->hard_header_len > max_hard_header_len)
 406                         max_hard_header_len = primary_dev->hard_header_len;
 407         }
 408
 409         standby_dev = rcu_dereference(nfo_info->standby_dev);
 410         if (standby_dev) {
 411                 vlan_features =
 412                         netdev_increment_features(vlan_features,
 413                                                   standby_dev->vlan_features,
 414                                                   FAILOVER_VLAN_FEATURES);
 415                 enc_features =
 416                         netdev_increment_features(enc_features,
 417                                                   standby_dev->hw_enc_features,
 418                                                   FAILOVER_ENC_FEATURES);
 419
 420                 dst_release_flag &= standby_dev->priv_flags;
 421                 if (standby_dev->hard_header_len > max_hard_header_len)
 422                         max_hard_header_len = standby_dev->hard_header_len;
 423         }
 424
 425         dev->vlan_features = vlan_features;
 426         dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL;
 427         dev->hard_header_len = max_hard_header_len;
 428
 429         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
 430         if (dst_release_flag == (IFF_XMIT_DST_RELEASE |
 431                                  IFF_XMIT_DST_RELEASE_PERM))
 432                 dev->priv_flags |= IFF_XMIT_DST_RELEASE;
 433
 434         netdev_change_features(dev);
 435 }
 436
 437 static void net_failover_lower_state_changed(struct net_device *slave_dev,
 438                                              struct net_device *primary_dev,
 439                                              struct net_device *standby_dev)
 440 {
 441         struct netdev_lag_lower_state_info info;
 442
 443         if (netif_carrier_ok(slave_dev))
 444                 info.link_up = true;
 445         else
 446                 info.link_up = false;
 447
 448         if (slave_dev == primary_dev) {
 449                 if (netif_running(primary_dev))
 450                         info.tx_enabled = true;
 451                 else
 452                         info.tx_enabled = false;
 453         } else {
 454                 if ((primary_dev && netif_running(primary_dev)) ||
 455                     (!netif_running(standby_dev)))
 456                         info.tx_enabled = false;
 457                 else
 458                         info.tx_enabled = true;
 459         }
 460
 461         netdev_lower_state_changed(slave_dev, &info);
 462 }
 463
 464 static int net_failover_slave_pre_register(struct net_device *slave_dev,
 465                                            struct net_device *failover_dev)
 466 {
 467         struct net_device *standby_dev, *primary_dev;
 468         struct net_failover_info *nfo_info;
 469         bool slave_is_standby;
 470
 471         nfo_info = netdev_priv(failover_dev);
 472         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 473         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 474         slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
 475         if (slave_is_standby ? standby_dev : primary_dev) {
 476                 netdev_err(failover_dev, "%s attempting to register as slave dev when %s already present\n",
 477                            slave_dev->name,
 478                            slave_is_standby ? "standby" : "primary");
 479                 return -EINVAL;
 480         }
 481
 482         /* We want to allow only a direct attached VF device as a primary
 483          * netdev. As there is no easy way to check for a VF device, restrict
 484          * this to a pci device.
 485          */
 486         if (!slave_is_standby && (!slave_dev->dev.parent ||
 487                                   !dev_is_pci(slave_dev->dev.parent)))
 488                 return -EINVAL;
 489
 490         if (failover_dev->features & NETIF_F_VLAN_CHALLENGED &&
 491             vlan_uses_dev(failover_dev)) {
 492                 netdev_err(failover_dev, "Device %s is VLAN challenged and failover device has VLAN set up\n",
 493                            failover_dev->name);
 494                 return -EINVAL;
 495         }
 496
 497         return 0;
 498 }
 499
 500 static int net_failover_slave_register(struct net_device *slave_dev,
 501                                        struct net_device *failover_dev)
 502 {
 503         struct net_device *standby_dev, *primary_dev;
 504         struct net_failover_info *nfo_info;
 505         bool slave_is_standby;
 506         u32 orig_mtu;
 507         int err;
 508
 509         /* Align MTU of slave with failover dev */
 510         orig_mtu = slave_dev->mtu;
 511         err = dev_set_mtu(slave_dev, failover_dev->mtu);
 512         if (err) {
 513                 netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n",
 514                            slave_dev->name, failover_dev->mtu);
 515                 goto done;
 516         }
 517
 518         dev_hold(slave_dev);
 519
 520         if (netif_running(failover_dev)) {
 521                 err = dev_open(slave_dev);
 522                 if (err && (err != -EBUSY)) {
 523                         netdev_err(failover_dev, "Opening slave %s failed err:%d\n",
 524                                    slave_dev->name, err);
 525                         goto err_dev_open;
 526                 }
 527         }
 528
 529         netif_addr_lock_bh(failover_dev);
 530         dev_uc_sync_multiple(slave_dev, failover_dev);
 531         dev_mc_sync_multiple(slave_dev, failover_dev);
 532         netif_addr_unlock_bh(failover_dev);
 533
 534         err = vlan_vids_add_by_dev(slave_dev, failover_dev);
 535         if (err) {
 536                 netdev_err(failover_dev, "Failed to add vlan ids to device %s err:%d\n",
 537                            slave_dev->name, err);
 538                 goto err_vlan_add;
 539         }
 540
 541         nfo_info = netdev_priv(failover_dev);
 542         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 543         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 544         slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
 545
 546         if (slave_is_standby) {
 547                 rcu_assign_pointer(nfo_info->standby_dev, slave_dev);
 548                 standby_dev = slave_dev;
 549                 dev_get_stats(standby_dev, &nfo_info->standby_stats);
 550         } else {
 551                 rcu_assign_pointer(nfo_info->primary_dev, slave_dev);
 552                 primary_dev = slave_dev;
 553                 dev_get_stats(primary_dev, &nfo_info->primary_stats);
 554                 failover_dev->min_mtu = slave_dev->min_mtu;
 555                 failover_dev->max_mtu = slave_dev->max_mtu;
 556         }
 557
 558         net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
 559         net_failover_compute_features(failover_dev);
 560
 561         call_netdevice_notifiers(NETDEV_JOIN, slave_dev);
 562
 563         netdev_info(failover_dev, "failover %s slave:%s registered\n",
 564                     slave_is_standby ? "standby" : "primary", slave_dev->name);
 565
 566         return 0;
 567
 568 err_vlan_add:
 569         dev_uc_unsync(slave_dev, failover_dev);
 570         dev_mc_unsync(slave_dev, failover_dev);
 571         dev_close(slave_dev);
 572 err_dev_open:
 573         dev_put(slave_dev);
 574         dev_set_mtu(slave_dev, orig_mtu);
 575 done:
 576         return err;
 577 }
 578
 579 static int net_failover_slave_pre_unregister(struct net_device *slave_dev,
 580                                              struct net_device *failover_dev)
 581 {
 582         struct net_device *standby_dev, *primary_dev;
 583         struct net_failover_info *nfo_info;
 584
 585         nfo_info = netdev_priv(failover_dev);
 586         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 587         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 588
 589         if (slave_dev != primary_dev && slave_dev != standby_dev)
 590                 return -ENODEV;
 591
 592         return 0;
 593 }
 594
 595 static int net_failover_slave_unregister(struct net_device *slave_dev,
 596                                          struct net_device *failover_dev)
 597 {
 598         struct net_device *standby_dev, *primary_dev;
 599         struct net_failover_info *nfo_info;
 600         bool slave_is_standby;
 601
 602         nfo_info = netdev_priv(failover_dev);
 603         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 604         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 605
 606         vlan_vids_del_by_dev(slave_dev, failover_dev);
 607         dev_uc_unsync(slave_dev, failover_dev);
 608         dev_mc_unsync(slave_dev, failover_dev);
 609         dev_close(slave_dev);
 610
 611         nfo_info = netdev_priv(failover_dev);
 612         dev_get_stats(failover_dev, &nfo_info->failover_stats);
 613
 614         slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
 615         if (slave_is_standby) {
 616                 RCU_INIT_POINTER(nfo_info->standby_dev, NULL);
 617         } else {
 618                 RCU_INIT_POINTER(nfo_info->primary_dev, NULL);
 619                 if (standby_dev) {
 620                         failover_dev->min_mtu = standby_dev->min_mtu;
 621                         failover_dev->max_mtu = standby_dev->max_mtu;
 622                 }
 623         }
 624
 625         dev_put(slave_dev);
 626
 627         net_failover_compute_features(failover_dev);
 628
 629         netdev_info(failover_dev, "failover %s slave:%s unregistered\n",
 630                     slave_is_standby ? "standby" : "primary", slave_dev->name);
 631
 632         return 0;
 633 }
 634
 635 static int net_failover_slave_link_change(struct net_device *slave_dev,
 636                                           struct net_device *failover_dev)
 637 {
 638         struct net_device *primary_dev, *standby_dev;
 639         struct net_failover_info *nfo_info;
 640
 641         nfo_info = netdev_priv(failover_dev);
 642
 643         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 644         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 645
 646         if (slave_dev != primary_dev && slave_dev != standby_dev)
 647                 return -ENODEV;
 648
 649         if ((primary_dev && net_failover_xmit_ready(primary_dev)) ||
 650             (standby_dev && net_failover_xmit_ready(standby_dev))) {
 651                 netif_carrier_on(failover_dev);
 652                 netif_tx_wake_all_queues(failover_dev);
 653         } else {
 654                 dev_get_stats(failover_dev, &nfo_info->failover_stats);
 655                 netif_carrier_off(failover_dev);
 656                 netif_tx_stop_all_queues(failover_dev);
 657         }
 658
 659         net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
 660
 661         return 0;
 662 }
 663
 664 static int net_failover_slave_name_change(struct net_device *slave_dev,
 665                                           struct net_device *failover_dev)
 666 {
 667         struct net_device *primary_dev, *standby_dev;
 668         struct net_failover_info *nfo_info;
 669
 670         nfo_info = netdev_priv(failover_dev);
 671
 672         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 673         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 674
 675         if (slave_dev != primary_dev && slave_dev != standby_dev)
 676                 return -ENODEV;
 677
 678         /* We need to bring up the slave after the rename by udev in case
 679          * open failed with EBUSY when it was registered.
 680          */
 681         dev_open(slave_dev);
 682
 683         return 0;
 684 }
 685
 686 static struct failover_ops net_failover_ops = {
 687         .slave_pre_register     = net_failover_slave_pre_register,
 688         .slave_register         = net_failover_slave_register,
 689         .slave_pre_unregister   = net_failover_slave_pre_unregister,
 690         .slave_unregister       = net_failover_slave_unregister,
 691         .slave_link_change      = net_failover_slave_link_change,
 692         .slave_name_change      = net_failover_slave_name_change,
 693         .slave_handle_frame     = net_failover_handle_frame,
 694 };
 695
 696 /**
 697  * net_failover_create - Create and register a failover instance
 698  *
 699  * @dev: standby netdev
 700  *
 701  * Creates a failover netdev and registers a failover instance for a standby
 702  * netdev. Used by paravirtual drivers that use 3-netdev model.
 703  * The failover netdev acts as a master device and controls 2 slave devices -
 704  * the original standby netdev and a VF netdev with the same MAC gets
 705  * registered as primary netdev.
 706  *
 707  * Return: pointer to failover instance
 708  */
 709 struct failover *net_failover_create(struct net_device *standby_dev)
 710 {
 711         struct device *dev = standby_dev->dev.parent;
 712         struct net_device *failover_dev;
 713         struct failover *failover;
 714         int err;
 715
 716         /* Alloc at least 2 queues, for now we are going with 16 assuming
 717          * that VF devices being enslaved won't have too many queues.
 718          */
 719         failover_dev = alloc_etherdev_mq(sizeof(struct net_failover_info), 16);
 720         if (!failover_dev) {
 721                 dev_err(dev, "Unable to allocate failover_netdev!\n");
 722                 return ERR_PTR(-ENOMEM);
 723         }
 724
 725         dev_net_set(failover_dev, dev_net(standby_dev));
 726         SET_NETDEV_DEV(failover_dev, dev);
 727
 728         failover_dev->netdev_ops = &failover_dev_ops;
 729         failover_dev->ethtool_ops = &failover_ethtool_ops;
 730
 731         /* Initialize the device options */
 732         failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE;
 733         failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE |
 734                                        IFF_TX_SKB_SHARING);
 735
 736         /* don't acquire failover netdev's netif_tx_lock when transmitting */
 737         failover_dev->features |= NETIF_F_LLTX;
 738
 739         /* Don't allow failover devices to change network namespaces. */
 740         failover_dev->features |= NETIF_F_NETNS_LOCAL;
 741
 742         failover_dev->hw_features = FAILOVER_VLAN_FEATURES |
 743                                     NETIF_F_HW_VLAN_CTAG_TX |
 744                                     NETIF_F_HW_VLAN_CTAG_RX |
 745                                     NETIF_F_HW_VLAN_CTAG_FILTER;
 746
 747         failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL;
 748         failover_dev->features |= failover_dev->hw_features;
 749
 750         memcpy(failover_dev->dev_addr, standby_dev->dev_addr,
 751                failover_dev->addr_len);
 752
 753         failover_dev->min_mtu = standby_dev->min_mtu;
 754         failover_dev->max_mtu = standby_dev->max_mtu;
 755
 756         err = register_netdev(failover_dev);
 757         if (err) {
 758                 dev_err(dev, "Unable to register failover_dev!\n");
 759                 goto err_register_netdev;
 760         }
 761
 762         netif_carrier_off(failover_dev);
 763
 764         failover = failover_register(failover_dev, &net_failover_ops);
 765         if (IS_ERR(failover))
 766                 goto err_failover_register;
 767
 768         return failover;
 769
 770 err_failover_register:
 771         unregister_netdev(failover_dev);
 772 err_register_netdev:
 773         free_netdev(failover_dev);
 774
 775         return ERR_PTR(err);
 776 }
 777 EXPORT_SYMBOL_GPL(net_failover_create);
 778
 779 /**
 780  * net_failover_destroy - Destroy a failover instance
 781  *
 782  * @failover: pointer to failover instance
 783  *
 784  * Unregisters any slave netdevs associated with the failover instance by
 785  * calling failover_slave_unregister().
 786  * unregisters the failover instance itself and finally frees the failover
 787  * netdev. Used by paravirtual drivers that use 3-netdev model.
 788  *
 789  */
 790 void net_failover_destroy(struct failover *failover)
 791 {
 792         struct net_failover_info *nfo_info;
 793         struct net_device *failover_dev;
 794         struct net_device *slave_dev;
 795
 796         if (!failover)
 797                 return;
 798
 799         failover_dev = rcu_dereference(failover->failover_dev);
 800         nfo_info = netdev_priv(failover_dev);
 801
 802         netif_device_detach(failover_dev);
 803
 804         rtnl_lock();
 805
 806         slave_dev = rtnl_dereference(nfo_info->primary_dev);
 807         if (slave_dev)
 808                 failover_slave_unregister(slave_dev);
 809
 810         slave_dev = rtnl_dereference(nfo_info->standby_dev);
 811         if (slave_dev)
 812                 failover_slave_unregister(slave_dev);
 813
 814         failover_unregister(failover);
 815
 816         unregister_netdevice(failover_dev);
 817
 818         rtnl_unlock();
 819
 820         free_netdev(failover_dev);
 821 }
 822 EXPORT_SYMBOL_GPL(net_failover_destroy);
 823
 824 static __init int
 825 net_failover_init(void)
 826 {
 827         return 0;
 828 }
 829 module_init(net_failover_init);
 830
 831 static __exit
 832 void net_failover_exit(void)
 833 {
 834 }
 835 module_exit(net_failover_exit);
 836
 837 MODULE_DESCRIPTION("Failover driver for Paravirtual drivers");
 838 MODULE_LICENSE("GPL v2");