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