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