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         if (primary_dev)
  66                 dev_close(primary_dev);
  67 err_primary_open:
  68         netif_tx_disable(dev);
  69         return err;
  70 }
  71
  72 static int net_failover_close(struct net_device *dev)
  73 {
  74         struct net_failover_info *nfo_info = netdev_priv(dev);
  75         struct net_device *slave_dev;
  76
  77         netif_tx_disable(dev);
  78
  79         slave_dev = rtnl_dereference(nfo_info->primary_dev);
  80         if (slave_dev)
  81                 dev_close(slave_dev);
  82
  83         slave_dev = rtnl_dereference(nfo_info->standby_dev);
  84         if (slave_dev)
  85                 dev_close(slave_dev);
  86
  87         return 0;
  88 }
  89
  90 static netdev_tx_t net_failover_drop_xmit(struct sk_buff *skb,
  91                                           struct net_device *dev)
  92 {
  93         atomic_long_inc(&dev->tx_dropped);
  94         dev_kfree_skb_any(skb);
  95         return NETDEV_TX_OK;
  96 }
  97
  98 static netdev_tx_t net_failover_start_xmit(struct sk_buff *skb,
  99                                            struct net_device *dev)
 100 {
 101         struct net_failover_info *nfo_info = netdev_priv(dev);
 102         struct net_device *xmit_dev;
 103
 104         /* Try xmit via primary netdev followed by standby netdev */
 105         xmit_dev = rcu_dereference_bh(nfo_info->primary_dev);
 106         if (!xmit_dev || !net_failover_xmit_ready(xmit_dev)) {
 107                 xmit_dev = rcu_dereference_bh(nfo_info->standby_dev);
 108                 if (!xmit_dev || !net_failover_xmit_ready(xmit_dev))
 109                         return net_failover_drop_xmit(skb, dev);
 110         }
 111
 112         skb->dev = xmit_dev;
 113         skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping;
 114
 115         return dev_queue_xmit(skb);
 116 }
 117
 118 static u16 net_failover_select_queue(struct net_device *dev,
 119                                      struct sk_buff *skb,
 120                                      struct net_device *sb_dev,
 121                                      select_queue_fallback_t fallback)
 122 {
 123         struct net_failover_info *nfo_info = netdev_priv(dev);
 124         struct net_device *primary_dev;
 125         u16 txq;
 126
 127         primary_dev = rcu_dereference(nfo_info->primary_dev);
 128         if (primary_dev) {
 129                 const struct net_device_ops *ops = primary_dev->netdev_ops;
 130
 131                 if (ops->ndo_select_queue)
 132                         txq = ops->ndo_select_queue(primary_dev, skb,
 133                                                     sb_dev, fallback);
 134                 else
 135                         txq = fallback(primary_dev, skb, NULL);
 136
 137                 qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
 138
 139                 return txq;
 140         }
 141
 142         txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0;
 143
 144         /* Save the original txq to restore before passing to the driver */
 145         qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
 146
 147         if (unlikely(txq >= dev->real_num_tx_queues)) {
 148                 do {
 149                         txq -= dev->real_num_tx_queues;
 150                 } while (txq >= dev->real_num_tx_queues);
 151         }
 152
 153         return txq;
 154 }
 155
 156 /* fold stats, assuming all rtnl_link_stats64 fields are u64, but
 157  * that some drivers can provide 32bit values only.
 158  */
 159 static void net_failover_fold_stats(struct rtnl_link_stats64 *_res,
 160                                     const struct rtnl_link_stats64 *_new,
 161                                     const struct rtnl_link_stats64 *_old)
 162 {
 163         const u64 *new = (const u64 *)_new;
 164         const u64 *old = (const u64 *)_old;
 165         u64 *res = (u64 *)_res;
 166         int i;
 167
 168         for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) {
 169                 u64 nv = new[i];
 170                 u64 ov = old[i];
 171                 s64 delta = nv - ov;
 172
 173                 /* detects if this particular field is 32bit only */
 174                 if (((nv | ov) >> 32) == 0)
 175                         delta = (s64)(s32)((u32)nv - (u32)ov);
 176
 177                 /* filter anomalies, some drivers reset their stats
 178                  * at down/up events.
 179                  */
 180                 if (delta > 0)
 181                         res[i] += delta;
 182         }
 183 }
 184
 185 static void net_failover_get_stats(struct net_device *dev,
 186                                    struct rtnl_link_stats64 *stats)
 187 {
 188         struct net_failover_info *nfo_info = netdev_priv(dev);
 189         const struct rtnl_link_stats64 *new;
 190         struct rtnl_link_stats64 temp;
 191         struct net_device *slave_dev;
 192
 193         spin_lock(&nfo_info->stats_lock);
 194         memcpy(stats, &nfo_info->failover_stats, sizeof(*stats));
 195
 196         rcu_read_lock();
 197
 198         slave_dev = rcu_dereference(nfo_info->primary_dev);
 199         if (slave_dev) {
 200                 new = dev_get_stats(slave_dev, &temp);
 201                 net_failover_fold_stats(stats, new, &nfo_info->primary_stats);
 202                 memcpy(&nfo_info->primary_stats, new, sizeof(*new));
 203         }
 204
 205         slave_dev = rcu_dereference(nfo_info->standby_dev);
 206         if (slave_dev) {
 207                 new = dev_get_stats(slave_dev, &temp);
 208                 net_failover_fold_stats(stats, new, &nfo_info->standby_stats);
 209                 memcpy(&nfo_info->standby_stats, new, sizeof(*new));
 210         }
 211
 212         rcu_read_unlock();
 213
 214         memcpy(&nfo_info->failover_stats, stats, sizeof(*stats));
 215         spin_unlock(&nfo_info->stats_lock);
 216 }
 217
 218 static int net_failover_change_mtu(struct net_device *dev, int new_mtu)
 219 {
 220         struct net_failover_info *nfo_info = netdev_priv(dev);
 221         struct net_device *primary_dev, *standby_dev;
 222         int ret = 0;
 223
 224         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 225         if (primary_dev) {
 226                 ret = dev_set_mtu(primary_dev, new_mtu);
 227                 if (ret)
 228                         return ret;
 229         }
 230
 231         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 232         if (standby_dev) {
 233                 ret = dev_set_mtu(standby_dev, new_mtu);
 234                 if (ret) {
 235                         if (primary_dev)
 236                                 dev_set_mtu(primary_dev, dev->mtu);
 237                         return ret;
 238                 }
 239         }
 240
 241         dev->mtu = new_mtu;
 242
 243         return 0;
 244 }
 245
 246 static void net_failover_set_rx_mode(struct net_device *dev)
 247 {
 248         struct net_failover_info *nfo_info = netdev_priv(dev);
 249         struct net_device *slave_dev;
 250
 251         rcu_read_lock();
 252
 253         slave_dev = rcu_dereference(nfo_info->primary_dev);
 254         if (slave_dev) {
 255                 dev_uc_sync_multiple(slave_dev, dev);
 256                 dev_mc_sync_multiple(slave_dev, dev);
 257         }
 258
 259         slave_dev = rcu_dereference(nfo_info->standby_dev);
 260         if (slave_dev) {
 261                 dev_uc_sync_multiple(slave_dev, dev);
 262                 dev_mc_sync_multiple(slave_dev, dev);
 263         }
 264
 265         rcu_read_unlock();
 266 }
 267
 268 static int net_failover_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 269                                         u16 vid)
 270 {
 271         struct net_failover_info *nfo_info = netdev_priv(dev);
 272         struct net_device *primary_dev, *standby_dev;
 273         int ret = 0;
 274
 275         primary_dev = rcu_dereference(nfo_info->primary_dev);
 276         if (primary_dev) {
 277                 ret = vlan_vid_add(primary_dev, proto, vid);
 278                 if (ret)
 279                         return ret;
 280         }
 281
 282         standby_dev = rcu_dereference(nfo_info->standby_dev);
 283         if (standby_dev) {
 284                 ret = vlan_vid_add(standby_dev, proto, vid);
 285                 if (ret)
 286                         if (primary_dev)
 287                                 vlan_vid_del(primary_dev, proto, vid);
 288         }
 289
 290         return ret;
 291 }
 292
 293 static int net_failover_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
 294                                          u16 vid)
 295 {
 296         struct net_failover_info *nfo_info = netdev_priv(dev);
 297         struct net_device *slave_dev;
 298
 299         slave_dev = rcu_dereference(nfo_info->primary_dev);
 300         if (slave_dev)
 301                 vlan_vid_del(slave_dev, proto, vid);
 302
 303         slave_dev = rcu_dereference(nfo_info->standby_dev);
 304         if (slave_dev)
 305                 vlan_vid_del(slave_dev, proto, vid);
 306
 307         return 0;
 308 }
 309
 310 static const struct net_device_ops failover_dev_ops = {
 311         .ndo_open               = net_failover_open,
 312         .ndo_stop               = net_failover_close,
 313         .ndo_start_xmit         = net_failover_start_xmit,
 314         .ndo_select_queue       = net_failover_select_queue,
 315         .ndo_get_stats64        = net_failover_get_stats,
 316         .ndo_change_mtu         = net_failover_change_mtu,
 317         .ndo_set_rx_mode        = net_failover_set_rx_mode,
 318         .ndo_vlan_rx_add_vid    = net_failover_vlan_rx_add_vid,
 319         .ndo_vlan_rx_kill_vid   = net_failover_vlan_rx_kill_vid,
 320         .ndo_validate_addr      = eth_validate_addr,
 321         .ndo_features_check     = passthru_features_check,
 322 };
 323
 324 #define FAILOVER_NAME "net_failover"
 325 #define FAILOVER_VERSION "0.1"
 326
 327 static void nfo_ethtool_get_drvinfo(struct net_device *dev,
 328                                     struct ethtool_drvinfo *drvinfo)
 329 {
 330         strlcpy(drvinfo->driver, FAILOVER_NAME, sizeof(drvinfo->driver));
 331         strlcpy(drvinfo->version, FAILOVER_VERSION, sizeof(drvinfo->version));
 332 }
 333
 334 static int nfo_ethtool_get_link_ksettings(struct net_device *dev,
 335                                           struct ethtool_link_ksettings *cmd)
 336 {
 337         struct net_failover_info *nfo_info = netdev_priv(dev);
 338         struct net_device *slave_dev;
 339
 340         slave_dev = rtnl_dereference(nfo_info->primary_dev);
 341         if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
 342                 slave_dev = rtnl_dereference(nfo_info->standby_dev);
 343                 if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
 344                         cmd->base.duplex = DUPLEX_UNKNOWN;
 345                         cmd->base.port = PORT_OTHER;
 346                         cmd->base.speed = SPEED_UNKNOWN;
 347
 348                         return 0;
 349                 }
 350         }
 351
 352         return __ethtool_get_link_ksettings(slave_dev, cmd);
 353 }
 354
 355 static const struct ethtool_ops failover_ethtool_ops = {
 356         .get_drvinfo            = nfo_ethtool_get_drvinfo,
 357         .get_link               = ethtool_op_get_link,
 358         .get_link_ksettings     = nfo_ethtool_get_link_ksettings,
 359 };
 360
 361 /* Called when slave dev is injecting data into network stack.
 362  * Change the associated network device from lower dev to failover dev.
 363  * note: already called with rcu_read_lock
 364  */
 365 static rx_handler_result_t net_failover_handle_frame(struct sk_buff **pskb)
 366 {
 367         struct sk_buff *skb = *pskb;
 368         struct net_device *dev = rcu_dereference(skb->dev->rx_handler_data);
 369         struct net_failover_info *nfo_info = netdev_priv(dev);
 370         struct net_device *primary_dev, *standby_dev;
 371
 372         primary_dev = rcu_dereference(nfo_info->primary_dev);
 373         standby_dev = rcu_dereference(nfo_info->standby_dev);
 374
 375         if (primary_dev && skb->dev == standby_dev)
 376                 return RX_HANDLER_EXACT;
 377
 378         skb->dev = dev;
 379
 380         return RX_HANDLER_ANOTHER;
 381 }
 382
 383 static void net_failover_compute_features(struct net_device *dev)
 384 {
 385         netdev_features_t vlan_features = FAILOVER_VLAN_FEATURES &
 386                                           NETIF_F_ALL_FOR_ALL;
 387         netdev_features_t enc_features  = FAILOVER_ENC_FEATURES;
 388         unsigned short max_hard_header_len = ETH_HLEN;
 389         unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
 390                                         IFF_XMIT_DST_RELEASE_PERM;
 391         struct net_failover_info *nfo_info = netdev_priv(dev);
 392         struct net_device *primary_dev, *standby_dev;
 393
 394         primary_dev = rcu_dereference(nfo_info->primary_dev);
 395         if (primary_dev) {
 396                 vlan_features =
 397                         netdev_increment_features(vlan_features,
 398                                                   primary_dev->vlan_features,
 399                                                   FAILOVER_VLAN_FEATURES);
 400                 enc_features =
 401                         netdev_increment_features(enc_features,
 402                                                   primary_dev->hw_enc_features,
 403                                                   FAILOVER_ENC_FEATURES);
 404
 405                 dst_release_flag &= primary_dev->priv_flags;
 406                 if (primary_dev->hard_header_len > max_hard_header_len)
 407                         max_hard_header_len = primary_dev->hard_header_len;
 408         }
 409
 410         standby_dev = rcu_dereference(nfo_info->standby_dev);
 411         if (standby_dev) {
 412                 vlan_features =
 413                         netdev_increment_features(vlan_features,
 414                                                   standby_dev->vlan_features,
 415                                                   FAILOVER_VLAN_FEATURES);
 416                 enc_features =
 417                         netdev_increment_features(enc_features,
 418                                                   standby_dev->hw_enc_features,
 419                                                   FAILOVER_ENC_FEATURES);
 420
 421                 dst_release_flag &= standby_dev->priv_flags;
 422                 if (standby_dev->hard_header_len > max_hard_header_len)
 423                         max_hard_header_len = standby_dev->hard_header_len;
 424         }
 425
 426         dev->vlan_features = vlan_features;
 427         dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL;
 428         dev->hard_header_len = max_hard_header_len;
 429
 430         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
 431         if (dst_release_flag == (IFF_XMIT_DST_RELEASE |
 432                                  IFF_XMIT_DST_RELEASE_PERM))
 433                 dev->priv_flags |= IFF_XMIT_DST_RELEASE;
 434
 435         netdev_change_features(dev);
 436 }
 437
 438 static void net_failover_lower_state_changed(struct net_device *slave_dev,
 439                                              struct net_device *primary_dev,
 440                                              struct net_device *standby_dev)
 441 {
 442         struct netdev_lag_lower_state_info info;
 443
 444         if (netif_carrier_ok(slave_dev))
 445                 info.link_up = true;
 446         else
 447                 info.link_up = false;
 448
 449         if (slave_dev == primary_dev) {
 450                 if (netif_running(primary_dev))
 451                         info.tx_enabled = true;
 452                 else
 453                         info.tx_enabled = false;
 454         } else {
 455                 if ((primary_dev && netif_running(primary_dev)) ||
 456                     (!netif_running(standby_dev)))
 457                         info.tx_enabled = false;
 458                 else
 459                         info.tx_enabled = true;
 460         }
 461
 462         netdev_lower_state_changed(slave_dev, &info);
 463 }
 464
 465 static int net_failover_slave_pre_register(struct net_device *slave_dev,
 466                                            struct net_device *failover_dev)
 467 {
 468         struct net_device *standby_dev, *primary_dev;
 469         struct net_failover_info *nfo_info;
 470         bool slave_is_standby;
 471
 472         nfo_info = netdev_priv(failover_dev);
 473         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 474         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 475         slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
 476         if (slave_is_standby ? standby_dev : primary_dev) {
 477                 netdev_err(failover_dev, "%s attempting to register as slave dev when %s already present\n",
 478                            slave_dev->name,
 479                            slave_is_standby ? "standby" : "primary");
 480                 return -EINVAL;
 481         }
 482
 483         /* We want to allow only a direct attached VF device as a primary
 484          * netdev. As there is no easy way to check for a VF device, restrict
 485          * this to a pci device.
 486          */
 487         if (!slave_is_standby && (!slave_dev->dev.parent ||
 488                                   !dev_is_pci(slave_dev->dev.parent)))
 489                 return -EINVAL;
 490
 491         if (failover_dev->features & NETIF_F_VLAN_CHALLENGED &&
 492             vlan_uses_dev(failover_dev)) {
 493                 netdev_err(failover_dev, "Device %s is VLAN challenged and failover device has VLAN set up\n",
 494                            failover_dev->name);
 495                 return -EINVAL;
 496         }
 497
 498         return 0;
 499 }
 500
 501 static int net_failover_slave_register(struct net_device *slave_dev,
 502                                        struct net_device *failover_dev)
 503 {
 504         struct net_device *standby_dev, *primary_dev;
 505         struct net_failover_info *nfo_info;
 506         bool slave_is_standby;
 507         u32 orig_mtu;
 508         int err;
 509
 510         /* Align MTU of slave with failover dev */
 511         orig_mtu = slave_dev->mtu;
 512         err = dev_set_mtu(slave_dev, failover_dev->mtu);
 513         if (err) {
 514                 netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n",
 515                            slave_dev->name, failover_dev->mtu);
 516                 goto done;
 517         }
 518
 519         dev_hold(slave_dev);
 520
 521         if (netif_running(failover_dev)) {
 522                 err = dev_open(slave_dev);
 523                 if (err && (err != -EBUSY)) {
 524                         netdev_err(failover_dev, "Opening slave %s failed err:%d\n",
 525                                    slave_dev->name, err);
 526                         goto err_dev_open;
 527                 }
 528         }
 529
 530         netif_addr_lock_bh(failover_dev);
 531         dev_uc_sync_multiple(slave_dev, failover_dev);
 532         dev_mc_sync_multiple(slave_dev, failover_dev);
 533         netif_addr_unlock_bh(failover_dev);
 534
 535         err = vlan_vids_add_by_dev(slave_dev, failover_dev);
 536         if (err) {
 537                 netdev_err(failover_dev, "Failed to add vlan ids to device %s err:%d\n",
 538                            slave_dev->name, err);
 539                 goto err_vlan_add;
 540         }
 541
 542         nfo_info = netdev_priv(failover_dev);
 543         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 544         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 545         slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
 546
 547         if (slave_is_standby) {
 548                 rcu_assign_pointer(nfo_info->standby_dev, slave_dev);
 549                 standby_dev = slave_dev;
 550                 dev_get_stats(standby_dev, &nfo_info->standby_stats);
 551         } else {
 552                 rcu_assign_pointer(nfo_info->primary_dev, slave_dev);
 553                 primary_dev = slave_dev;
 554                 dev_get_stats(primary_dev, &nfo_info->primary_stats);
 555                 failover_dev->min_mtu = slave_dev->min_mtu;
 556                 failover_dev->max_mtu = slave_dev->max_mtu;
 557         }
 558
 559         net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
 560         net_failover_compute_features(failover_dev);
 561
 562         call_netdevice_notifiers(NETDEV_JOIN, slave_dev);
 563
 564         netdev_info(failover_dev, "failover %s slave:%s registered\n",
 565                     slave_is_standby ? "standby" : "primary", slave_dev->name);
 566
 567         return 0;
 568
 569 err_vlan_add:
 570         dev_uc_unsync(slave_dev, failover_dev);
 571         dev_mc_unsync(slave_dev, failover_dev);
 572         dev_close(slave_dev);
 573 err_dev_open:
 574         dev_put(slave_dev);
 575         dev_set_mtu(slave_dev, orig_mtu);
 576 done:
 577         return err;
 578 }
 579
 580 static int net_failover_slave_pre_unregister(struct net_device *slave_dev,
 581                                              struct net_device *failover_dev)
 582 {
 583         struct net_device *standby_dev, *primary_dev;
 584         struct net_failover_info *nfo_info;
 585
 586         nfo_info = netdev_priv(failover_dev);
 587         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 588         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 589
 590         if (slave_dev != primary_dev && slave_dev != standby_dev)
 591                 return -ENODEV;
 592
 593         return 0;
 594 }
 595
 596 static int net_failover_slave_unregister(struct net_device *slave_dev,
 597                                          struct net_device *failover_dev)
 598 {
 599         struct net_device *standby_dev, *primary_dev;
 600         struct net_failover_info *nfo_info;
 601         bool slave_is_standby;
 602
 603         nfo_info = netdev_priv(failover_dev);
 604         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 605         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 606
 607         if (WARN_ON_ONCE(slave_dev != primary_dev && slave_dev != standby_dev))
 608                 return -ENODEV;
 609
 610         vlan_vids_del_by_dev(slave_dev, failover_dev);
 611         dev_uc_unsync(slave_dev, failover_dev);
 612         dev_mc_unsync(slave_dev, failover_dev);
 613         dev_close(slave_dev);
 614
 615         nfo_info = netdev_priv(failover_dev);
 616         dev_get_stats(failover_dev, &nfo_info->failover_stats);
 617
 618         slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
 619         if (slave_is_standby) {
 620                 RCU_INIT_POINTER(nfo_info->standby_dev, NULL);
 621         } else {
 622                 RCU_INIT_POINTER(nfo_info->primary_dev, NULL);
 623                 if (standby_dev) {
 624                         failover_dev->min_mtu = standby_dev->min_mtu;
 625                         failover_dev->max_mtu = standby_dev->max_mtu;
 626                 }
 627         }
 628
 629         dev_put(slave_dev);
 630
 631         net_failover_compute_features(failover_dev);
 632
 633         netdev_info(failover_dev, "failover %s slave:%s unregistered\n",
 634                     slave_is_standby ? "standby" : "primary", slave_dev->name);
 635
 636         return 0;
 637 }
 638
 639 static int net_failover_slave_link_change(struct net_device *slave_dev,
 640                                           struct net_device *failover_dev)
 641 {
 642         struct net_device *primary_dev, *standby_dev;
 643         struct net_failover_info *nfo_info;
 644
 645         nfo_info = netdev_priv(failover_dev);
 646
 647         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 648         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 649
 650         if (slave_dev != primary_dev && slave_dev != standby_dev)
 651                 return -ENODEV;
 652
 653         if ((primary_dev && net_failover_xmit_ready(primary_dev)) ||
 654             (standby_dev && net_failover_xmit_ready(standby_dev))) {
 655                 netif_carrier_on(failover_dev);
 656                 netif_tx_wake_all_queues(failover_dev);
 657         } else {
 658                 dev_get_stats(failover_dev, &nfo_info->failover_stats);
 659                 netif_carrier_off(failover_dev);
 660                 netif_tx_stop_all_queues(failover_dev);
 661         }
 662
 663         net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
 664
 665         return 0;
 666 }
 667
 668 static int net_failover_slave_name_change(struct net_device *slave_dev,
 669                                           struct net_device *failover_dev)
 670 {
 671         struct net_device *primary_dev, *standby_dev;
 672         struct net_failover_info *nfo_info;
 673
 674         nfo_info = netdev_priv(failover_dev);
 675
 676         primary_dev = rtnl_dereference(nfo_info->primary_dev);
 677         standby_dev = rtnl_dereference(nfo_info->standby_dev);
 678
 679         if (slave_dev != primary_dev && slave_dev != standby_dev)
 680                 return -ENODEV;
 681
 682         /* We need to bring up the slave after the rename by udev in case
 683          * open failed with EBUSY when it was registered.
 684          */
 685         dev_open(slave_dev);
 686
 687         return 0;
 688 }
 689
 690 static struct failover_ops net_failover_ops = {
 691         .slave_pre_register     = net_failover_slave_pre_register,
 692         .slave_register         = net_failover_slave_register,
 693         .slave_pre_unregister   = net_failover_slave_pre_unregister,
 694         .slave_unregister       = net_failover_slave_unregister,
 695         .slave_link_change      = net_failover_slave_link_change,
 696         .slave_name_change      = net_failover_slave_name_change,
 697         .slave_handle_frame     = net_failover_handle_frame,
 698 };
 699
 700 /**
 701  * net_failover_create - Create and register a failover instance
 702  *
 703  * @dev: standby netdev
 704  *
 705  * Creates a failover netdev and registers a failover instance for a standby
 706  * netdev. Used by paravirtual drivers that use 3-netdev model.
 707  * The failover netdev acts as a master device and controls 2 slave devices -
 708  * the original standby netdev and a VF netdev with the same MAC gets
 709  * registered as primary netdev.
 710  *
 711  * Return: pointer to failover instance
 712  */
 713 struct failover *net_failover_create(struct net_device *standby_dev)
 714 {
 715         struct device *dev = standby_dev->dev.parent;
 716         struct net_device *failover_dev;
 717         struct failover *failover;
 718         int err;
 719
 720         /* Alloc at least 2 queues, for now we are going with 16 assuming
 721          * that VF devices being enslaved won't have too many queues.
 722          */
 723         failover_dev = alloc_etherdev_mq(sizeof(struct net_failover_info), 16);
 724         if (!failover_dev) {
 725                 dev_err(dev, "Unable to allocate failover_netdev!\n");
 726                 return ERR_PTR(-ENOMEM);
 727         }
 728
 729         dev_net_set(failover_dev, dev_net(standby_dev));
 730         SET_NETDEV_DEV(failover_dev, dev);
 731
 732         failover_dev->netdev_ops = &failover_dev_ops;
 733         failover_dev->ethtool_ops = &failover_ethtool_ops;
 734
 735         /* Initialize the device options */
 736         failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE;
 737         failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE |
 738                                        IFF_TX_SKB_SHARING);
 739
 740         /* don't acquire failover netdev's netif_tx_lock when transmitting */
 741         failover_dev->features |= NETIF_F_LLTX;
 742
 743         /* Don't allow failover devices to change network namespaces. */
 744         failover_dev->features |= NETIF_F_NETNS_LOCAL;
 745
 746         failover_dev->hw_features = FAILOVER_VLAN_FEATURES |
 747                                     NETIF_F_HW_VLAN_CTAG_TX |
 748                                     NETIF_F_HW_VLAN_CTAG_RX |
 749                                     NETIF_F_HW_VLAN_CTAG_FILTER;
 750
 751         failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL;
 752         failover_dev->features |= failover_dev->hw_features;
 753
 754         memcpy(failover_dev->dev_addr, standby_dev->dev_addr,
 755                failover_dev->addr_len);
 756
 757         failover_dev->min_mtu = standby_dev->min_mtu;
 758         failover_dev->max_mtu = standby_dev->max_mtu;
 759
 760         err = register_netdev(failover_dev);
 761         if (err) {
 762                 dev_err(dev, "Unable to register failover_dev!\n");
 763                 goto err_register_netdev;
 764         }
 765
 766         netif_carrier_off(failover_dev);
 767
 768         failover = failover_register(failover_dev, &net_failover_ops);
 769         if (IS_ERR(failover)) {
 770                 err = PTR_ERR(failover);
 771                 goto err_failover_register;
 772         }
 773
 774         return failover;
 775
 776 err_failover_register:
 777         unregister_netdev(failover_dev);
 778 err_register_netdev:
 779         free_netdev(failover_dev);
 780
 781         return ERR_PTR(err);
 782 }
 783 EXPORT_SYMBOL_GPL(net_failover_create);
 784
 785 /**
 786  * net_failover_destroy - Destroy a failover instance
 787  *
 788  * @failover: pointer to failover instance
 789  *
 790  * Unregisters any slave netdevs associated with the failover instance by
 791  * calling failover_slave_unregister().
 792  * unregisters the failover instance itself and finally frees the failover
 793  * netdev. Used by paravirtual drivers that use 3-netdev model.
 794  *
 795  */
 796 void net_failover_destroy(struct failover *failover)
 797 {
 798         struct net_failover_info *nfo_info;
 799         struct net_device *failover_dev;
 800         struct net_device *slave_dev;
 801
 802         if (!failover)
 803                 return;
 804
 805         failover_dev = rcu_dereference(failover->failover_dev);
 806         nfo_info = netdev_priv(failover_dev);
 807
 808         netif_device_detach(failover_dev);
 809
 810         rtnl_lock();
 811
 812         slave_dev = rtnl_dereference(nfo_info->primary_dev);
 813         if (slave_dev)
 814                 failover_slave_unregister(slave_dev);
 815
 816         slave_dev = rtnl_dereference(nfo_info->standby_dev);
 817         if (slave_dev)
 818                 failover_slave_unregister(slave_dev);
 819
 820         failover_unregister(failover);
 821
 822         unregister_netdevice(failover_dev);
 823
 824         rtnl_unlock();
 825
 826         free_netdev(failover_dev);
 827 }
 828 EXPORT_SYMBOL_GPL(net_failover_destroy);
 829
 830 static __init int
 831 net_failover_init(void)
 832 {
 833         return 0;
 834 }
 835 module_init(net_failover_init);
 836
 837 static __exit
 838 void net_failover_exit(void)
 839 {
 840 }
 841 module_exit(net_failover_exit);
 842
 843 MODULE_DESCRIPTION("Failover driver for Paravirtual drivers");
 844 MODULE_LICENSE("GPL v2");