drivers/net/veth.c

   1 /*
   2  *  drivers/net/veth.c
   3  *
   4  *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
   5  *
   6  * Author: Pavel Emelianov <xemul@openvz.org>
   7  * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
   8  *
   9  */
  10
  11 #include <linux/netdevice.h>
  12 #include <linux/slab.h>
  13 #include <linux/ethtool.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/u64_stats_sync.h>
  16
  17 #include <net/rtnetlink.h>
  18 #include <net/dst.h>
  19 #include <net/xfrm.h>
  20 #include <net/xdp.h>
  21 #include <linux/veth.h>
  22 #include <linux/module.h>
  23 #include <linux/bpf.h>
  24 #include <linux/filter.h>
  25 #include <linux/ptr_ring.h>
  26 #include <linux/bpf_trace.h>
  27 #include <linux/net_tstamp.h>
  28
  29 #define DRV_NAME        "veth"
  30 #define DRV_VERSION     "1.0"
  31
  32 #define VETH_XDP_FLAG           BIT(0)
  33 #define VETH_RING_SIZE          256
  34 #define VETH_XDP_HEADROOM       (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
  35
  36 /* Separating two types of XDP xmit */
  37 #define VETH_XDP_TX             BIT(0)
  38 #define VETH_XDP_REDIR          BIT(1)
  39
  40 struct veth_rq_stats {
  41         u64                     xdp_packets;
  42         u64                     xdp_bytes;
  43         u64                     xdp_drops;
  44         struct u64_stats_sync   syncp;
  45 };
  46
  47 struct veth_rq {
  48         struct napi_struct      xdp_napi;
  49         struct net_device       *dev;
  50         struct bpf_prog __rcu   *xdp_prog;
  51         struct xdp_mem_info     xdp_mem;
  52         struct veth_rq_stats    stats;
  53         bool                    rx_notify_masked;
  54         struct ptr_ring         xdp_ring;
  55         struct xdp_rxq_info     xdp_rxq;
  56 };
  57
  58 struct veth_priv {
  59         struct net_device __rcu *peer;
  60         atomic64_t              dropped;
  61         struct bpf_prog         *_xdp_prog;
  62         struct veth_rq          *rq;
  63         unsigned int            requested_headroom;
  64 };
  65
  66 /*
  67  * ethtool interface
  68  */
  69
  70 struct veth_q_stat_desc {
  71         char    desc[ETH_GSTRING_LEN];
  72         size_t  offset;
  73 };
  74
  75 #define VETH_RQ_STAT(m) offsetof(struct veth_rq_stats, m)
  76
  77 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  78         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  79         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  80         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
  81 };
  82
  83 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
  84
  85 static struct {
  86         const char string[ETH_GSTRING_LEN];
  87 } ethtool_stats_keys[] = {
  88         { "peer_ifindex" },
  89 };
  90
  91 static int veth_get_link_ksettings(struct net_device *dev,
  92                                    struct ethtool_link_ksettings *cmd)
  93 {
  94         cmd->base.speed         = SPEED_10000;
  95         cmd->base.duplex        = DUPLEX_FULL;
  96         cmd->base.port          = PORT_TP;
  97         cmd->base.autoneg       = AUTONEG_DISABLE;
  98         return 0;
  99 }
 100
 101 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 102 {
 103         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 104         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 105 }
 106
 107 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 108 {
 109         char *p = (char *)buf;
 110         int i, j;
 111
 112         switch(stringset) {
 113         case ETH_SS_STATS:
 114                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 115                 p += sizeof(ethtool_stats_keys);
 116                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 117                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 118                                 snprintf(p, ETH_GSTRING_LEN, "rx_queue_%u_%s",
 119                                          i, veth_rq_stats_desc[j].desc);
 120                                 p += ETH_GSTRING_LEN;
 121                         }
 122                 }
 123                 break;
 124         }
 125 }
 126
 127 static int veth_get_sset_count(struct net_device *dev, int sset)
 128 {
 129         switch (sset) {
 130         case ETH_SS_STATS:
 131                 return ARRAY_SIZE(ethtool_stats_keys) +
 132                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues;
 133         default:
 134                 return -EOPNOTSUPP;
 135         }
 136 }
 137
 138 static void veth_get_ethtool_stats(struct net_device *dev,
 139                 struct ethtool_stats *stats, u64 *data)
 140 {
 141         struct veth_priv *priv = netdev_priv(dev);
 142         struct net_device *peer = rtnl_dereference(priv->peer);
 143         int i, j, idx;
 144
 145         data[0] = peer ? peer->ifindex : 0;
 146         idx = 1;
 147         for (i = 0; i < dev->real_num_rx_queues; i++) {
 148                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 149                 const void *stats_base = (void *)rq_stats;
 150                 unsigned int start;
 151                 size_t offset;
 152
 153                 do {
 154                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 155                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 156                                 offset = veth_rq_stats_desc[j].offset;
 157                                 data[idx + j] = *(u64 *)(stats_base + offset);
 158                         }
 159                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 160                 idx += VETH_RQ_STATS_LEN;
 161         }
 162 }
 163
 164 static int veth_get_ts_info(struct net_device *dev,
 165                             struct ethtool_ts_info *info)
 166 {
 167         info->so_timestamping =
 168                 SOF_TIMESTAMPING_TX_SOFTWARE |
 169                 SOF_TIMESTAMPING_RX_SOFTWARE |
 170                 SOF_TIMESTAMPING_SOFTWARE;
 171         info->phc_index = -1;
 172
 173         return 0;
 174 }
 175
 176 static const struct ethtool_ops veth_ethtool_ops = {
 177         .get_drvinfo            = veth_get_drvinfo,
 178         .get_link               = ethtool_op_get_link,
 179         .get_strings            = veth_get_strings,
 180         .get_sset_count         = veth_get_sset_count,
 181         .get_ethtool_stats      = veth_get_ethtool_stats,
 182         .get_link_ksettings     = veth_get_link_ksettings,
 183         .get_ts_info            = veth_get_ts_info,
 184 };
 185
 186 /* general routines */
 187
 188 static bool veth_is_xdp_frame(void *ptr)
 189 {
 190         return (unsigned long)ptr & VETH_XDP_FLAG;
 191 }
 192
 193 static void *veth_ptr_to_xdp(void *ptr)
 194 {
 195         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 196 }
 197
 198 static void *veth_xdp_to_ptr(void *ptr)
 199 {
 200         return (void *)((unsigned long)ptr | VETH_XDP_FLAG);
 201 }
 202
 203 static void veth_ptr_free(void *ptr)
 204 {
 205         if (veth_is_xdp_frame(ptr))
 206                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 207         else
 208                 kfree_skb(ptr);
 209 }
 210
 211 static void __veth_xdp_flush(struct veth_rq *rq)
 212 {
 213         /* Write ptr_ring before reading rx_notify_masked */
 214         smp_mb();
 215         if (!rq->rx_notify_masked) {
 216                 rq->rx_notify_masked = true;
 217                 napi_schedule(&rq->xdp_napi);
 218         }
 219 }
 220
 221 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 222 {
 223         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 224                 dev_kfree_skb_any(skb);
 225                 return NET_RX_DROP;
 226         }
 227
 228         return NET_RX_SUCCESS;
 229 }
 230
 231 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 232                             struct veth_rq *rq, bool xdp)
 233 {
 234         return __dev_forward_skb(dev, skb) ?: xdp ?
 235                 veth_xdp_rx(rq, skb) :
 236                 netif_rx(skb);
 237 }
 238
 239 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 240 {
 241         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 242         struct veth_rq *rq = NULL;
 243         struct net_device *rcv;
 244         int length = skb->len;
 245         bool rcv_xdp = false;
 246         int rxq;
 247
 248         rcu_read_lock();
 249         rcv = rcu_dereference(priv->peer);
 250         if (unlikely(!rcv)) {
 251                 kfree_skb(skb);
 252                 goto drop;
 253         }
 254
 255         rcv_priv = netdev_priv(rcv);
 256         rxq = skb_get_queue_mapping(skb);
 257         if (rxq < rcv->real_num_rx_queues) {
 258                 rq = &rcv_priv->rq[rxq];
 259                 rcv_xdp = rcu_access_pointer(rq->xdp_prog);
 260                 if (rcv_xdp)
 261                         skb_record_rx_queue(skb, rxq);
 262         }
 263
 264         skb_tx_timestamp(skb);
 265         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 266                 if (!rcv_xdp) {
 267                         struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
 268
 269                         u64_stats_update_begin(&stats->syncp);
 270                         stats->bytes += length;
 271                         stats->packets++;
 272                         u64_stats_update_end(&stats->syncp);
 273                 }
 274         } else {
 275 drop:
 276                 atomic64_inc(&priv->dropped);
 277         }
 278
 279         if (rcv_xdp)
 280                 __veth_xdp_flush(rq);
 281
 282         rcu_read_unlock();
 283
 284         return NETDEV_TX_OK;
 285 }
 286
 287 static u64 veth_stats_tx(struct pcpu_lstats *result, struct net_device *dev)
 288 {
 289         struct veth_priv *priv = netdev_priv(dev);
 290         int cpu;
 291
 292         result->packets = 0;
 293         result->bytes = 0;
 294         for_each_possible_cpu(cpu) {
 295                 struct pcpu_lstats *stats = per_cpu_ptr(dev->lstats, cpu);
 296                 u64 packets, bytes;
 297                 unsigned int start;
 298
 299                 do {
 300                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 301                         packets = stats->packets;
 302                         bytes = stats->bytes;
 303                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 304                 result->packets += packets;
 305                 result->bytes += bytes;
 306         }
 307         return atomic64_read(&priv->dropped);
 308 }
 309
 310 static void veth_stats_rx(struct veth_rq_stats *result, struct net_device *dev)
 311 {
 312         struct veth_priv *priv = netdev_priv(dev);
 313         int i;
 314
 315         result->xdp_packets = 0;
 316         result->xdp_bytes = 0;
 317         result->xdp_drops = 0;
 318         for (i = 0; i < dev->num_rx_queues; i++) {
 319                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 320                 u64 packets, bytes, drops;
 321                 unsigned int start;
 322
 323                 do {
 324                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 325                         packets = stats->xdp_packets;
 326                         bytes = stats->xdp_bytes;
 327                         drops = stats->xdp_drops;
 328                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 329                 result->xdp_packets += packets;
 330                 result->xdp_bytes += bytes;
 331                 result->xdp_drops += drops;
 332         }
 333 }
 334
 335 static void veth_get_stats64(struct net_device *dev,
 336                              struct rtnl_link_stats64 *tot)
 337 {
 338         struct veth_priv *priv = netdev_priv(dev);
 339         struct net_device *peer;
 340         struct veth_rq_stats rx;
 341         struct pcpu_lstats tx;
 342
 343         tot->tx_dropped = veth_stats_tx(&tx, dev);
 344         tot->tx_bytes = tx.bytes;
 345         tot->tx_packets = tx.packets;
 346
 347         veth_stats_rx(&rx, dev);
 348         tot->rx_dropped = rx.xdp_drops;
 349         tot->rx_bytes = rx.xdp_bytes;
 350         tot->rx_packets = rx.xdp_packets;
 351
 352         rcu_read_lock();
 353         peer = rcu_dereference(priv->peer);
 354         if (peer) {
 355                 tot->rx_dropped += veth_stats_tx(&tx, peer);
 356                 tot->rx_bytes += tx.bytes;
 357                 tot->rx_packets += tx.packets;
 358
 359                 veth_stats_rx(&rx, peer);
 360                 tot->tx_bytes += rx.xdp_bytes;
 361                 tot->tx_packets += rx.xdp_packets;
 362         }
 363         rcu_read_unlock();
 364 }
 365
 366 /* fake multicast ability */
 367 static void veth_set_multicast_list(struct net_device *dev)
 368 {
 369 }
 370
 371 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 372                                       int buflen)
 373 {
 374         struct sk_buff *skb;
 375
 376         if (!buflen) {
 377                 buflen = SKB_DATA_ALIGN(headroom + len) +
 378                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 379         }
 380         skb = build_skb(head, buflen);
 381         if (!skb)
 382                 return NULL;
 383
 384         skb_reserve(skb, headroom);
 385         skb_put(skb, len);
 386
 387         return skb;
 388 }
 389
 390 static int veth_select_rxq(struct net_device *dev)
 391 {
 392         return smp_processor_id() % dev->real_num_rx_queues;
 393 }
 394
 395 static int veth_xdp_xmit(struct net_device *dev, int n,
 396                          struct xdp_frame **frames, u32 flags)
 397 {
 398         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 399         struct net_device *rcv;
 400         int i, ret, drops = n;
 401         unsigned int max_len;
 402         struct veth_rq *rq;
 403
 404         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) {
 405                 ret = -EINVAL;
 406                 goto drop;
 407         }
 408
 409         rcv = rcu_dereference(priv->peer);
 410         if (unlikely(!rcv)) {
 411                 ret = -ENXIO;
 412                 goto drop;
 413         }
 414
 415         rcv_priv = netdev_priv(rcv);
 416         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 417         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 418          * side. This means an XDP program is loaded on the peer and the peer
 419          * device is up.
 420          */
 421         if (!rcu_access_pointer(rq->xdp_prog)) {
 422                 ret = -ENXIO;
 423                 goto drop;
 424         }
 425
 426         drops = 0;
 427         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 428
 429         spin_lock(&rq->xdp_ring.producer_lock);
 430         for (i = 0; i < n; i++) {
 431                 struct xdp_frame *frame = frames[i];
 432                 void *ptr = veth_xdp_to_ptr(frame);
 433
 434                 if (unlikely(frame->len > max_len ||
 435                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 436                         xdp_return_frame_rx_napi(frame);
 437                         drops++;
 438                 }
 439         }
 440         spin_unlock(&rq->xdp_ring.producer_lock);
 441
 442         if (flags & XDP_XMIT_FLUSH)
 443                 __veth_xdp_flush(rq);
 444
 445         if (likely(!drops))
 446                 return n;
 447
 448         ret = n - drops;
 449 drop:
 450         atomic64_add(drops, &priv->dropped);
 451
 452         return ret;
 453 }
 454
 455 static void veth_xdp_flush(struct net_device *dev)
 456 {
 457         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 458         struct net_device *rcv;
 459         struct veth_rq *rq;
 460
 461         rcu_read_lock();
 462         rcv = rcu_dereference(priv->peer);
 463         if (unlikely(!rcv))
 464                 goto out;
 465
 466         rcv_priv = netdev_priv(rcv);
 467         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 468         /* xdp_ring is initialized on receive side? */
 469         if (unlikely(!rcu_access_pointer(rq->xdp_prog)))
 470                 goto out;
 471
 472         __veth_xdp_flush(rq);
 473 out:
 474         rcu_read_unlock();
 475 }
 476
 477 static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
 478 {
 479         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
 480
 481         if (unlikely(!frame))
 482                 return -EOVERFLOW;
 483
 484         return veth_xdp_xmit(dev, 1, &frame, 0);
 485 }
 486
 487 static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 488                                         struct xdp_frame *frame,
 489                                         unsigned int *xdp_xmit)
 490 {
 491         void *hard_start = frame->data - frame->headroom;
 492         void *head = hard_start - sizeof(struct xdp_frame);
 493         int len = frame->len, delta = 0;
 494         struct xdp_frame orig_frame;
 495         struct bpf_prog *xdp_prog;
 496         unsigned int headroom;
 497         struct sk_buff *skb;
 498
 499         rcu_read_lock();
 500         xdp_prog = rcu_dereference(rq->xdp_prog);
 501         if (likely(xdp_prog)) {
 502                 struct xdp_buff xdp;
 503                 u32 act;
 504
 505                 xdp.data_hard_start = hard_start;
 506                 xdp.data = frame->data;
 507                 xdp.data_end = frame->data + frame->len;
 508                 xdp.data_meta = frame->data - frame->metasize;
 509                 xdp.rxq = &rq->xdp_rxq;
 510
 511                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 512
 513                 switch (act) {
 514                 case XDP_PASS:
 515                         delta = frame->data - xdp.data;
 516                         len = xdp.data_end - xdp.data;
 517                         break;
 518                 case XDP_TX:
 519                         orig_frame = *frame;
 520                         xdp.data_hard_start = head;
 521                         xdp.rxq->mem = frame->mem;
 522                         if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 523                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 524                                 frame = &orig_frame;
 525                                 goto err_xdp;
 526                         }
 527                         *xdp_xmit |= VETH_XDP_TX;
 528                         rcu_read_unlock();
 529                         goto xdp_xmit;
 530                 case XDP_REDIRECT:
 531                         orig_frame = *frame;
 532                         xdp.data_hard_start = head;
 533                         xdp.rxq->mem = frame->mem;
 534                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 535                                 frame = &orig_frame;
 536                                 goto err_xdp;
 537                         }
 538                         *xdp_xmit |= VETH_XDP_REDIR;
 539                         rcu_read_unlock();
 540                         goto xdp_xmit;
 541                 default:
 542                         bpf_warn_invalid_xdp_action(act);
 543                 case XDP_ABORTED:
 544                         trace_xdp_exception(rq->dev, xdp_prog, act);
 545                 case XDP_DROP:
 546                         goto err_xdp;
 547                 }
 548         }
 549         rcu_read_unlock();
 550
 551         headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
 552         skb = veth_build_skb(head, headroom, len, 0);
 553         if (!skb) {
 554                 xdp_return_frame(frame);
 555                 goto err;
 556         }
 557
 558         xdp_scrub_frame(frame);
 559         skb->protocol = eth_type_trans(skb, rq->dev);
 560 err:
 561         return skb;
 562 err_xdp:
 563         rcu_read_unlock();
 564         xdp_return_frame(frame);
 565 xdp_xmit:
 566         return NULL;
 567 }
 568
 569 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq, struct sk_buff *skb,
 570                                         unsigned int *xdp_xmit)
 571 {
 572         u32 pktlen, headroom, act, metalen;
 573         void *orig_data, *orig_data_end;
 574         struct bpf_prog *xdp_prog;
 575         int mac_len, delta, off;
 576         struct xdp_buff xdp;
 577
 578         skb_orphan(skb);
 579
 580         rcu_read_lock();
 581         xdp_prog = rcu_dereference(rq->xdp_prog);
 582         if (unlikely(!xdp_prog)) {
 583                 rcu_read_unlock();
 584                 goto out;
 585         }
 586
 587         mac_len = skb->data - skb_mac_header(skb);
 588         pktlen = skb->len + mac_len;
 589         headroom = skb_headroom(skb) - mac_len;
 590
 591         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 592             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 593                 struct sk_buff *nskb;
 594                 int size, head_off;
 595                 void *head, *start;
 596                 struct page *page;
 597
 598                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 599                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 600                 if (size > PAGE_SIZE)
 601                         goto drop;
 602
 603                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 604                 if (!page)
 605                         goto drop;
 606
 607                 head = page_address(page);
 608                 start = head + VETH_XDP_HEADROOM;
 609                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 610                         page_frag_free(head);
 611                         goto drop;
 612                 }
 613
 614                 nskb = veth_build_skb(head,
 615                                       VETH_XDP_HEADROOM + mac_len, skb->len,
 616                                       PAGE_SIZE);
 617                 if (!nskb) {
 618                         page_frag_free(head);
 619                         goto drop;
 620                 }
 621
 622                 skb_copy_header(nskb, skb);
 623                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 624                 skb_headers_offset_update(nskb, head_off);
 625                 consume_skb(skb);
 626                 skb = nskb;
 627         }
 628
 629         xdp.data_hard_start = skb->head;
 630         xdp.data = skb_mac_header(skb);
 631         xdp.data_end = xdp.data + pktlen;
 632         xdp.data_meta = xdp.data;
 633         xdp.rxq = &rq->xdp_rxq;
 634         orig_data = xdp.data;
 635         orig_data_end = xdp.data_end;
 636
 637         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 638
 639         switch (act) {
 640         case XDP_PASS:
 641                 break;
 642         case XDP_TX:
 643                 get_page(virt_to_page(xdp.data));
 644                 consume_skb(skb);
 645                 xdp.rxq->mem = rq->xdp_mem;
 646                 if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 647                         trace_xdp_exception(rq->dev, xdp_prog, act);
 648                         goto err_xdp;
 649                 }
 650                 *xdp_xmit |= VETH_XDP_TX;
 651                 rcu_read_unlock();
 652                 goto xdp_xmit;
 653         case XDP_REDIRECT:
 654                 get_page(virt_to_page(xdp.data));
 655                 consume_skb(skb);
 656                 xdp.rxq->mem = rq->xdp_mem;
 657                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog))
 658                         goto err_xdp;
 659                 *xdp_xmit |= VETH_XDP_REDIR;
 660                 rcu_read_unlock();
 661                 goto xdp_xmit;
 662         default:
 663                 bpf_warn_invalid_xdp_action(act);
 664         case XDP_ABORTED:
 665                 trace_xdp_exception(rq->dev, xdp_prog, act);
 666         case XDP_DROP:
 667                 goto drop;
 668         }
 669         rcu_read_unlock();
 670
 671         delta = orig_data - xdp.data;
 672         off = mac_len + delta;
 673         if (off > 0)
 674                 __skb_push(skb, off);
 675         else if (off < 0)
 676                 __skb_pull(skb, -off);
 677         skb->mac_header -= delta;
 678         off = xdp.data_end - orig_data_end;
 679         if (off != 0)
 680                 __skb_put(skb, off);
 681         skb->protocol = eth_type_trans(skb, rq->dev);
 682
 683         metalen = xdp.data - xdp.data_meta;
 684         if (metalen)
 685                 skb_metadata_set(skb, metalen);
 686 out:
 687         return skb;
 688 drop:
 689         rcu_read_unlock();
 690         kfree_skb(skb);
 691         return NULL;
 692 err_xdp:
 693         rcu_read_unlock();
 694         page_frag_free(xdp.data);
 695 xdp_xmit:
 696         return NULL;
 697 }
 698
 699 static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit)
 700 {
 701         int i, done = 0, drops = 0, bytes = 0;
 702
 703         for (i = 0; i < budget; i++) {
 704                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 705                 unsigned int xdp_xmit_one = 0;
 706                 struct sk_buff *skb;
 707
 708                 if (!ptr)
 709                         break;
 710
 711                 if (veth_is_xdp_frame(ptr)) {
 712                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 713
 714                         bytes += frame->len;
 715                         skb = veth_xdp_rcv_one(rq, frame, &xdp_xmit_one);
 716                 } else {
 717                         skb = ptr;
 718                         bytes += skb->len;
 719                         skb = veth_xdp_rcv_skb(rq, skb, &xdp_xmit_one);
 720                 }
 721                 *xdp_xmit |= xdp_xmit_one;
 722
 723                 if (skb)
 724                         napi_gro_receive(&rq->xdp_napi, skb);
 725                 else if (!xdp_xmit_one)
 726                         drops++;
 727
 728                 done++;
 729         }
 730
 731         u64_stats_update_begin(&rq->stats.syncp);
 732         rq->stats.xdp_packets += done;
 733         rq->stats.xdp_bytes += bytes;
 734         rq->stats.xdp_drops += drops;
 735         u64_stats_update_end(&rq->stats.syncp);
 736
 737         return done;
 738 }
 739
 740 static int veth_poll(struct napi_struct *napi, int budget)
 741 {
 742         struct veth_rq *rq =
 743                 container_of(napi, struct veth_rq, xdp_napi);
 744         unsigned int xdp_xmit = 0;
 745         int done;
 746
 747         xdp_set_return_frame_no_direct();
 748         done = veth_xdp_rcv(rq, budget, &xdp_xmit);
 749
 750         if (done < budget && napi_complete_done(napi, done)) {
 751                 /* Write rx_notify_masked before reading ptr_ring */
 752                 smp_store_mb(rq->rx_notify_masked, false);
 753                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 754                         rq->rx_notify_masked = true;
 755                         napi_schedule(&rq->xdp_napi);
 756                 }
 757         }
 758
 759         if (xdp_xmit & VETH_XDP_TX)
 760                 veth_xdp_flush(rq->dev);
 761         if (xdp_xmit & VETH_XDP_REDIR)
 762                 xdp_do_flush_map();
 763         xdp_clear_return_frame_no_direct();
 764
 765         return done;
 766 }
 767
 768 static int veth_napi_add(struct net_device *dev)
 769 {
 770         struct veth_priv *priv = netdev_priv(dev);
 771         int err, i;
 772
 773         for (i = 0; i < dev->real_num_rx_queues; i++) {
 774                 struct veth_rq *rq = &priv->rq[i];
 775
 776                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 777                 if (err)
 778                         goto err_xdp_ring;
 779         }
 780
 781         for (i = 0; i < dev->real_num_rx_queues; i++) {
 782                 struct veth_rq *rq = &priv->rq[i];
 783
 784                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 785                 napi_enable(&rq->xdp_napi);
 786         }
 787
 788         return 0;
 789 err_xdp_ring:
 790         for (i--; i >= 0; i--)
 791                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 792
 793         return err;
 794 }
 795
 796 static void veth_napi_del(struct net_device *dev)
 797 {
 798         struct veth_priv *priv = netdev_priv(dev);
 799         int i;
 800
 801         for (i = 0; i < dev->real_num_rx_queues; i++) {
 802                 struct veth_rq *rq = &priv->rq[i];
 803
 804                 napi_disable(&rq->xdp_napi);
 805                 napi_hash_del(&rq->xdp_napi);
 806         }
 807         synchronize_net();
 808
 809         for (i = 0; i < dev->real_num_rx_queues; i++) {
 810                 struct veth_rq *rq = &priv->rq[i];
 811
 812                 netif_napi_del(&rq->xdp_napi);
 813                 rq->rx_notify_masked = false;
 814                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 815         }
 816 }
 817
 818 static int veth_enable_xdp(struct net_device *dev)
 819 {
 820         struct veth_priv *priv = netdev_priv(dev);
 821         int err, i;
 822
 823         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 824                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 825                         struct veth_rq *rq = &priv->rq[i];
 826
 827                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i);
 828                         if (err < 0)
 829                                 goto err_rxq_reg;
 830
 831                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 832                                                          MEM_TYPE_PAGE_SHARED,
 833                                                          NULL);
 834                         if (err < 0)
 835                                 goto err_reg_mem;
 836
 837                         /* Save original mem info as it can be overwritten */
 838                         rq->xdp_mem = rq->xdp_rxq.mem;
 839                 }
 840
 841                 err = veth_napi_add(dev);
 842                 if (err)
 843                         goto err_rxq_reg;
 844         }
 845
 846         for (i = 0; i < dev->real_num_rx_queues; i++)
 847                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 848
 849         return 0;
 850 err_reg_mem:
 851         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 852 err_rxq_reg:
 853         for (i--; i >= 0; i--)
 854                 xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 855
 856         return err;
 857 }
 858
 859 static void veth_disable_xdp(struct net_device *dev)
 860 {
 861         struct veth_priv *priv = netdev_priv(dev);
 862         int i;
 863
 864         for (i = 0; i < dev->real_num_rx_queues; i++)
 865                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 866         veth_napi_del(dev);
 867         for (i = 0; i < dev->real_num_rx_queues; i++) {
 868                 struct veth_rq *rq = &priv->rq[i];
 869
 870                 rq->xdp_rxq.mem = rq->xdp_mem;
 871                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 872         }
 873 }
 874
 875 static int veth_open(struct net_device *dev)
 876 {
 877         struct veth_priv *priv = netdev_priv(dev);
 878         struct net_device *peer = rtnl_dereference(priv->peer);
 879         int err;
 880
 881         if (!peer)
 882                 return -ENOTCONN;
 883
 884         if (priv->_xdp_prog) {
 885                 err = veth_enable_xdp(dev);
 886                 if (err)
 887                         return err;
 888         }
 889
 890         if (peer->flags & IFF_UP) {
 891                 netif_carrier_on(dev);
 892                 netif_carrier_on(peer);
 893         }
 894
 895         return 0;
 896 }
 897
 898 static int veth_close(struct net_device *dev)
 899 {
 900         struct veth_priv *priv = netdev_priv(dev);
 901         struct net_device *peer = rtnl_dereference(priv->peer);
 902
 903         netif_carrier_off(dev);
 904         if (peer)
 905                 netif_carrier_off(peer);
 906
 907         if (priv->_xdp_prog)
 908                 veth_disable_xdp(dev);
 909
 910         return 0;
 911 }
 912
 913 static int is_valid_veth_mtu(int mtu)
 914 {
 915         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
 916 }
 917
 918 static int veth_alloc_queues(struct net_device *dev)
 919 {
 920         struct veth_priv *priv = netdev_priv(dev);
 921         int i;
 922
 923         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
 924         if (!priv->rq)
 925                 return -ENOMEM;
 926
 927         for (i = 0; i < dev->num_rx_queues; i++) {
 928                 priv->rq[i].dev = dev;
 929                 u64_stats_init(&priv->rq[i].stats.syncp);
 930         }
 931
 932         return 0;
 933 }
 934
 935 static void veth_free_queues(struct net_device *dev)
 936 {
 937         struct veth_priv *priv = netdev_priv(dev);
 938
 939         kfree(priv->rq);
 940 }
 941
 942 static int veth_dev_init(struct net_device *dev)
 943 {
 944         int err;
 945
 946         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
 947         if (!dev->lstats)
 948                 return -ENOMEM;
 949
 950         err = veth_alloc_queues(dev);
 951         if (err) {
 952                 free_percpu(dev->lstats);
 953                 return err;
 954         }
 955
 956         return 0;
 957 }
 958
 959 static void veth_dev_free(struct net_device *dev)
 960 {
 961         veth_free_queues(dev);
 962         free_percpu(dev->lstats);
 963 }
 964
 965 #ifdef CONFIG_NET_POLL_CONTROLLER
 966 static void veth_poll_controller(struct net_device *dev)
 967 {
 968         /* veth only receives frames when its peer sends one
 969          * Since it has nothing to do with disabling irqs, we are guaranteed
 970          * never to have pending data when we poll for it so
 971          * there is nothing to do here.
 972          *
 973          * We need this though so netpoll recognizes us as an interface that
 974          * supports polling, which enables bridge devices in virt setups to
 975          * still use netconsole
 976          */
 977 }
 978 #endif  /* CONFIG_NET_POLL_CONTROLLER */
 979
 980 static int veth_get_iflink(const struct net_device *dev)
 981 {
 982         struct veth_priv *priv = netdev_priv(dev);
 983         struct net_device *peer;
 984         int iflink;
 985
 986         rcu_read_lock();
 987         peer = rcu_dereference(priv->peer);
 988         iflink = peer ? peer->ifindex : 0;
 989         rcu_read_unlock();
 990
 991         return iflink;
 992 }
 993
 994 static netdev_features_t veth_fix_features(struct net_device *dev,
 995                                            netdev_features_t features)
 996 {
 997         struct veth_priv *priv = netdev_priv(dev);
 998         struct net_device *peer;
 999
1000         peer = rtnl_dereference(priv->peer);
1001         if (peer) {
1002                 struct veth_priv *peer_priv = netdev_priv(peer);
1003
1004                 if (peer_priv->_xdp_prog)
1005                         features &= ~NETIF_F_GSO_SOFTWARE;
1006         }
1007
1008         return features;
1009 }
1010
1011 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1012 {
1013         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1014         struct net_device *peer;
1015
1016         if (new_hr < 0)
1017                 new_hr = 0;
1018
1019         rcu_read_lock();
1020         peer = rcu_dereference(priv->peer);
1021         if (unlikely(!peer))
1022                 goto out;
1023
1024         peer_priv = netdev_priv(peer);
1025         priv->requested_headroom = new_hr;
1026         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1027         dev->needed_headroom = new_hr;
1028         peer->needed_headroom = new_hr;
1029
1030 out:
1031         rcu_read_unlock();
1032 }
1033
1034 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1035                         struct netlink_ext_ack *extack)
1036 {
1037         struct veth_priv *priv = netdev_priv(dev);
1038         struct bpf_prog *old_prog;
1039         struct net_device *peer;
1040         unsigned int max_mtu;
1041         int err;
1042
1043         old_prog = priv->_xdp_prog;
1044         priv->_xdp_prog = prog;
1045         peer = rtnl_dereference(priv->peer);
1046
1047         if (prog) {
1048                 if (!peer) {
1049                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1050                         err = -ENOTCONN;
1051                         goto err;
1052                 }
1053
1054                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
1055                           peer->hard_header_len -
1056                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1057                 if (peer->mtu > max_mtu) {
1058                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1059                         err = -ERANGE;
1060                         goto err;
1061                 }
1062
1063                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1064                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1065                         err = -ENOSPC;
1066                         goto err;
1067                 }
1068
1069                 if (dev->flags & IFF_UP) {
1070                         err = veth_enable_xdp(dev);
1071                         if (err) {
1072                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1073                                 goto err;
1074                         }
1075                 }
1076
1077                 if (!old_prog) {
1078                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1079                         peer->max_mtu = max_mtu;
1080                 }
1081         }
1082
1083         if (old_prog) {
1084                 if (!prog) {
1085                         if (dev->flags & IFF_UP)
1086                                 veth_disable_xdp(dev);
1087
1088                         if (peer) {
1089                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1090                                 peer->max_mtu = ETH_MAX_MTU;
1091                         }
1092                 }
1093                 bpf_prog_put(old_prog);
1094         }
1095
1096         if ((!!old_prog ^ !!prog) && peer)
1097                 netdev_update_features(peer);
1098
1099         return 0;
1100 err:
1101         priv->_xdp_prog = old_prog;
1102
1103         return err;
1104 }
1105
1106 static u32 veth_xdp_query(struct net_device *dev)
1107 {
1108         struct veth_priv *priv = netdev_priv(dev);
1109         const struct bpf_prog *xdp_prog;
1110
1111         xdp_prog = priv->_xdp_prog;
1112         if (xdp_prog)
1113                 return xdp_prog->aux->id;
1114
1115         return 0;
1116 }
1117
1118 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1119 {
1120         switch (xdp->command) {
1121         case XDP_SETUP_PROG:
1122                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1123         case XDP_QUERY_PROG:
1124                 xdp->prog_id = veth_xdp_query(dev);
1125                 return 0;
1126         default:
1127                 return -EINVAL;
1128         }
1129 }
1130
1131 static const struct net_device_ops veth_netdev_ops = {
1132         .ndo_init            = veth_dev_init,
1133         .ndo_open            = veth_open,
1134         .ndo_stop            = veth_close,
1135         .ndo_start_xmit      = veth_xmit,
1136         .ndo_get_stats64     = veth_get_stats64,
1137         .ndo_set_rx_mode     = veth_set_multicast_list,
1138         .ndo_set_mac_address = eth_mac_addr,
1139 #ifdef CONFIG_NET_POLL_CONTROLLER
1140         .ndo_poll_controller    = veth_poll_controller,
1141 #endif
1142         .ndo_get_iflink         = veth_get_iflink,
1143         .ndo_fix_features       = veth_fix_features,
1144         .ndo_features_check     = passthru_features_check,
1145         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1146         .ndo_bpf                = veth_xdp,
1147         .ndo_xdp_xmit           = veth_xdp_xmit,
1148 };
1149
1150 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1151                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1152                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1153                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1154                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1155
1156 static void veth_setup(struct net_device *dev)
1157 {
1158         ether_setup(dev);
1159
1160         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1161         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1162         dev->priv_flags |= IFF_NO_QUEUE;
1163         dev->priv_flags |= IFF_PHONY_HEADROOM;
1164
1165         dev->netdev_ops = &veth_netdev_ops;
1166         dev->ethtool_ops = &veth_ethtool_ops;
1167         dev->features |= NETIF_F_LLTX;
1168         dev->features |= VETH_FEATURES;
1169         dev->vlan_features = dev->features &
1170                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1171                                NETIF_F_HW_VLAN_STAG_TX |
1172                                NETIF_F_HW_VLAN_CTAG_RX |
1173                                NETIF_F_HW_VLAN_STAG_RX);
1174         dev->needs_free_netdev = true;
1175         dev->priv_destructor = veth_dev_free;
1176         dev->max_mtu = ETH_MAX_MTU;
1177
1178         dev->hw_features = VETH_FEATURES;
1179         dev->hw_enc_features = VETH_FEATURES;
1180         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1181 }
1182
1183 /*
1184  * netlink interface
1185  */
1186
1187 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1188                          struct netlink_ext_ack *extack)
1189 {
1190         if (tb[IFLA_ADDRESS]) {
1191                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1192                         return -EINVAL;
1193                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1194                         return -EADDRNOTAVAIL;
1195         }
1196         if (tb[IFLA_MTU]) {
1197                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1198                         return -EINVAL;
1199         }
1200         return 0;
1201 }
1202
1203 static struct rtnl_link_ops veth_link_ops;
1204
1205 static int veth_newlink(struct net *src_net, struct net_device *dev,
1206                         struct nlattr *tb[], struct nlattr *data[],
1207                         struct netlink_ext_ack *extack)
1208 {
1209         int err;
1210         struct net_device *peer;
1211         struct veth_priv *priv;
1212         char ifname[IFNAMSIZ];
1213         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1214         unsigned char name_assign_type;
1215         struct ifinfomsg *ifmp;
1216         struct net *net;
1217
1218         /*
1219          * create and register peer first
1220          */
1221         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1222                 struct nlattr *nla_peer;
1223
1224                 nla_peer = data[VETH_INFO_PEER];
1225                 ifmp = nla_data(nla_peer);
1226                 err = rtnl_nla_parse_ifla(peer_tb,
1227                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1228                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1229                                           NULL);
1230                 if (err < 0)
1231                         return err;
1232
1233                 err = veth_validate(peer_tb, NULL, extack);
1234                 if (err < 0)
1235                         return err;
1236
1237                 tbp = peer_tb;
1238         } else {
1239                 ifmp = NULL;
1240                 tbp = tb;
1241         }
1242
1243         if (ifmp && tbp[IFLA_IFNAME]) {
1244                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1245                 name_assign_type = NET_NAME_USER;
1246         } else {
1247                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1248                 name_assign_type = NET_NAME_ENUM;
1249         }
1250
1251         net = rtnl_link_get_net(src_net, tbp);
1252         if (IS_ERR(net))
1253                 return PTR_ERR(net);
1254
1255         peer = rtnl_create_link(net, ifname, name_assign_type,
1256                                 &veth_link_ops, tbp, extack);
1257         if (IS_ERR(peer)) {
1258                 put_net(net);
1259                 return PTR_ERR(peer);
1260         }
1261
1262         if (!ifmp || !tbp[IFLA_ADDRESS])
1263                 eth_hw_addr_random(peer);
1264
1265         if (ifmp && (dev->ifindex != 0))
1266                 peer->ifindex = ifmp->ifi_index;
1267
1268         peer->gso_max_size = dev->gso_max_size;
1269         peer->gso_max_segs = dev->gso_max_segs;
1270
1271         err = register_netdevice(peer);
1272         put_net(net);
1273         net = NULL;
1274         if (err < 0)
1275                 goto err_register_peer;
1276
1277         netif_carrier_off(peer);
1278
1279         err = rtnl_configure_link(peer, ifmp);
1280         if (err < 0)
1281                 goto err_configure_peer;
1282
1283         /*
1284          * register dev last
1285          *
1286          * note, that since we've registered new device the dev's name
1287          * should be re-allocated
1288          */
1289
1290         if (tb[IFLA_ADDRESS] == NULL)
1291                 eth_hw_addr_random(dev);
1292
1293         if (tb[IFLA_IFNAME])
1294                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1295         else
1296                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1297
1298         err = register_netdevice(dev);
1299         if (err < 0)
1300                 goto err_register_dev;
1301
1302         netif_carrier_off(dev);
1303
1304         /*
1305          * tie the deviced together
1306          */
1307
1308         priv = netdev_priv(dev);
1309         rcu_assign_pointer(priv->peer, peer);
1310
1311         priv = netdev_priv(peer);
1312         rcu_assign_pointer(priv->peer, dev);
1313
1314         return 0;
1315
1316 err_register_dev:
1317         /* nothing to do */
1318 err_configure_peer:
1319         unregister_netdevice(peer);
1320         return err;
1321
1322 err_register_peer:
1323         free_netdev(peer);
1324         return err;
1325 }
1326
1327 static void veth_dellink(struct net_device *dev, struct list_head *head)
1328 {
1329         struct veth_priv *priv;
1330         struct net_device *peer;
1331
1332         priv = netdev_priv(dev);
1333         peer = rtnl_dereference(priv->peer);
1334
1335         /* Note : dellink() is called from default_device_exit_batch(),
1336          * before a rcu_synchronize() point. The devices are guaranteed
1337          * not being freed before one RCU grace period.
1338          */
1339         RCU_INIT_POINTER(priv->peer, NULL);
1340         unregister_netdevice_queue(dev, head);
1341
1342         if (peer) {
1343                 priv = netdev_priv(peer);
1344                 RCU_INIT_POINTER(priv->peer, NULL);
1345                 unregister_netdevice_queue(peer, head);
1346         }
1347 }
1348
1349 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1350         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1351 };
1352
1353 static struct net *veth_get_link_net(const struct net_device *dev)
1354 {
1355         struct veth_priv *priv = netdev_priv(dev);
1356         struct net_device *peer = rtnl_dereference(priv->peer);
1357
1358         return peer ? dev_net(peer) : dev_net(dev);
1359 }
1360
1361 static struct rtnl_link_ops veth_link_ops = {
1362         .kind           = DRV_NAME,
1363         .priv_size      = sizeof(struct veth_priv),
1364         .setup          = veth_setup,
1365         .validate       = veth_validate,
1366         .newlink        = veth_newlink,
1367         .dellink        = veth_dellink,
1368         .policy         = veth_policy,
1369         .maxtype        = VETH_INFO_MAX,
1370         .get_link_net   = veth_get_link_net,
1371 };
1372
1373 /*
1374  * init/fini
1375  */
1376
1377 static __init int veth_init(void)
1378 {
1379         return rtnl_link_register(&veth_link_ops);
1380 }
1381
1382 static __exit void veth_exit(void)
1383 {
1384         rtnl_link_unregister(&veth_link_ops);
1385 }
1386
1387 module_init(veth_init);
1388 module_exit(veth_exit);
1389
1390 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1391 MODULE_LICENSE("GPL v2");
1392 MODULE_ALIAS_RTNL_LINK(DRV_NAME);