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