drivers/net/veth.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  drivers/net/veth.c
   4  *
   5  *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
   6  *
   7  * Author: Pavel Emelianov <xemul@openvz.org>
   8  * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
   9  *
  10  */
  11
  12 #include <linux/netdevice.h>
  13 #include <linux/slab.h>
  14 #include <linux/ethtool.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/u64_stats_sync.h>
  17
  18 #include <net/rtnetlink.h>
  19 #include <net/dst.h>
  20 #include <net/xfrm.h>
  21 #include <net/xdp.h>
  22 #include <linux/veth.h>
  23 #include <linux/module.h>
  24 #include <linux/bpf.h>
  25 #include <linux/filter.h>
  26 #include <linux/ptr_ring.h>
  27 #include <linux/bpf_trace.h>
  28 #include <linux/net_tstamp.h>
  29
  30 #define DRV_NAME        "veth"
  31 #define DRV_VERSION     "1.0"
  32
  33 #define VETH_XDP_FLAG           BIT(0)
  34 #define VETH_RING_SIZE          256
  35 #define VETH_XDP_HEADROOM       (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
  36
  37 /* Separating two types of XDP xmit */
  38 #define VETH_XDP_TX             BIT(0)
  39 #define VETH_XDP_REDIR          BIT(1)
  40
  41 struct veth_rq_stats {
  42         u64                     xdp_packets;
  43         u64                     xdp_bytes;
  44         u64                     xdp_drops;
  45         struct u64_stats_sync   syncp;
  46 };
  47
  48 struct veth_rq {
  49         struct napi_struct      xdp_napi;
  50         struct net_device       *dev;
  51         struct bpf_prog __rcu   *xdp_prog;
  52         struct xdp_mem_info     xdp_mem;
  53         struct veth_rq_stats    stats;
  54         bool                    rx_notify_masked;
  55         struct ptr_ring         xdp_ring;
  56         struct xdp_rxq_info     xdp_rxq;
  57 };
  58
  59 struct veth_priv {
  60         struct net_device __rcu *peer;
  61         atomic64_t              dropped;
  62         struct bpf_prog         *_xdp_prog;
  63         struct veth_rq          *rq;
  64         unsigned int            requested_headroom;
  65 };
  66
  67 /*
  68  * ethtool interface
  69  */
  70
  71 struct veth_q_stat_desc {
  72         char    desc[ETH_GSTRING_LEN];
  73         size_t  offset;
  74 };
  75
  76 #define VETH_RQ_STAT(m) offsetof(struct veth_rq_stats, m)
  77
  78 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  79         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  80         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  81         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
  82 };
  83
  84 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
  85
  86 static struct {
  87         const char string[ETH_GSTRING_LEN];
  88 } ethtool_stats_keys[] = {
  89         { "peer_ifindex" },
  90 };
  91
  92 static int veth_get_link_ksettings(struct net_device *dev,
  93                                    struct ethtool_link_ksettings *cmd)
  94 {
  95         cmd->base.speed         = SPEED_10000;
  96         cmd->base.duplex        = DUPLEX_FULL;
  97         cmd->base.port          = PORT_TP;
  98         cmd->base.autoneg       = AUTONEG_DISABLE;
  99         return 0;
 100 }
 101
 102 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 103 {
 104         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 105         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 106 }
 107
 108 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 109 {
 110         char *p = (char *)buf;
 111         int i, j;
 112
 113         switch(stringset) {
 114         case ETH_SS_STATS:
 115                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 116                 p += sizeof(ethtool_stats_keys);
 117                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 118                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 119                                 snprintf(p, ETH_GSTRING_LEN,
 120                                          "rx_queue_%u_%.11s",
 121                                          i, veth_rq_stats_desc[j].desc);
 122                                 p += ETH_GSTRING_LEN;
 123                         }
 124                 }
 125                 break;
 126         }
 127 }
 128
 129 static int veth_get_sset_count(struct net_device *dev, int sset)
 130 {
 131         switch (sset) {
 132         case ETH_SS_STATS:
 133                 return ARRAY_SIZE(ethtool_stats_keys) +
 134                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues;
 135         default:
 136                 return -EOPNOTSUPP;
 137         }
 138 }
 139
 140 static void veth_get_ethtool_stats(struct net_device *dev,
 141                 struct ethtool_stats *stats, u64 *data)
 142 {
 143         struct veth_priv *priv = netdev_priv(dev);
 144         struct net_device *peer = rtnl_dereference(priv->peer);
 145         int i, j, idx;
 146
 147         data[0] = peer ? peer->ifindex : 0;
 148         idx = 1;
 149         for (i = 0; i < dev->real_num_rx_queues; i++) {
 150                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 151                 const void *stats_base = (void *)rq_stats;
 152                 unsigned int start;
 153                 size_t offset;
 154
 155                 do {
 156                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 157                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 158                                 offset = veth_rq_stats_desc[j].offset;
 159                                 data[idx + j] = *(u64 *)(stats_base + offset);
 160                         }
 161                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 162                 idx += VETH_RQ_STATS_LEN;
 163         }
 164 }
 165
 166 static const struct ethtool_ops veth_ethtool_ops = {
 167         .get_drvinfo            = veth_get_drvinfo,
 168         .get_link               = ethtool_op_get_link,
 169         .get_strings            = veth_get_strings,
 170         .get_sset_count         = veth_get_sset_count,
 171         .get_ethtool_stats      = veth_get_ethtool_stats,
 172         .get_link_ksettings     = veth_get_link_ksettings,
 173         .get_ts_info            = ethtool_op_get_ts_info,
 174 };
 175
 176 /* general routines */
 177
 178 static bool veth_is_xdp_frame(void *ptr)
 179 {
 180         return (unsigned long)ptr & VETH_XDP_FLAG;
 181 }
 182
 183 static void *veth_ptr_to_xdp(void *ptr)
 184 {
 185         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 186 }
 187
 188 static void *veth_xdp_to_ptr(void *ptr)
 189 {
 190         return (void *)((unsigned long)ptr | VETH_XDP_FLAG);
 191 }
 192
 193 static void veth_ptr_free(void *ptr)
 194 {
 195         if (veth_is_xdp_frame(ptr))
 196                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 197         else
 198                 kfree_skb(ptr);
 199 }
 200
 201 static void __veth_xdp_flush(struct veth_rq *rq)
 202 {
 203         /* Write ptr_ring before reading rx_notify_masked */
 204         smp_mb();
 205         if (!rq->rx_notify_masked) {
 206                 rq->rx_notify_masked = true;
 207                 napi_schedule(&rq->xdp_napi);
 208         }
 209 }
 210
 211 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 212 {
 213         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 214                 dev_kfree_skb_any(skb);
 215                 return NET_RX_DROP;
 216         }
 217
 218         return NET_RX_SUCCESS;
 219 }
 220
 221 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 222                             struct veth_rq *rq, bool xdp)
 223 {
 224         return __dev_forward_skb(dev, skb) ?: xdp ?
 225                 veth_xdp_rx(rq, skb) :
 226                 netif_rx(skb);
 227 }
 228
 229 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 230 {
 231         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 232         struct veth_rq *rq = NULL;
 233         struct net_device *rcv;
 234         int length = skb->len;
 235         bool rcv_xdp = false;
 236         int rxq;
 237
 238         rcu_read_lock();
 239         rcv = rcu_dereference(priv->peer);
 240         if (unlikely(!rcv)) {
 241                 kfree_skb(skb);
 242                 goto drop;
 243         }
 244
 245         rcv_priv = netdev_priv(rcv);
 246         rxq = skb_get_queue_mapping(skb);
 247         if (rxq < rcv->real_num_rx_queues) {
 248                 rq = &rcv_priv->rq[rxq];
 249                 rcv_xdp = rcu_access_pointer(rq->xdp_prog);
 250                 if (rcv_xdp)
 251                         skb_record_rx_queue(skb, rxq);
 252         }
 253
 254         skb_tx_timestamp(skb);
 255         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 256                 if (!rcv_xdp) {
 257                         struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
 258
 259                         u64_stats_update_begin(&stats->syncp);
 260                         stats->bytes += length;
 261                         stats->packets++;
 262                         u64_stats_update_end(&stats->syncp);
 263                 }
 264         } else {
 265 drop:
 266                 atomic64_inc(&priv->dropped);
 267         }
 268
 269         if (rcv_xdp)
 270                 __veth_xdp_flush(rq);
 271
 272         rcu_read_unlock();
 273
 274         return NETDEV_TX_OK;
 275 }
 276
 277 static u64 veth_stats_tx(struct pcpu_lstats *result, struct net_device *dev)
 278 {
 279         struct veth_priv *priv = netdev_priv(dev);
 280         int cpu;
 281
 282         result->packets = 0;
 283         result->bytes = 0;
 284         for_each_possible_cpu(cpu) {
 285                 struct pcpu_lstats *stats = per_cpu_ptr(dev->lstats, cpu);
 286                 u64 packets, bytes;
 287                 unsigned int start;
 288
 289                 do {
 290                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 291                         packets = stats->packets;
 292                         bytes = stats->bytes;
 293                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 294                 result->packets += packets;
 295                 result->bytes += bytes;
 296         }
 297         return atomic64_read(&priv->dropped);
 298 }
 299
 300 static void veth_stats_rx(struct veth_rq_stats *result, struct net_device *dev)
 301 {
 302         struct veth_priv *priv = netdev_priv(dev);
 303         int i;
 304
 305         result->xdp_packets = 0;
 306         result->xdp_bytes = 0;
 307         result->xdp_drops = 0;
 308         for (i = 0; i < dev->num_rx_queues; i++) {
 309                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 310                 u64 packets, bytes, drops;
 311                 unsigned int start;
 312
 313                 do {
 314                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 315                         packets = stats->xdp_packets;
 316                         bytes = stats->xdp_bytes;
 317                         drops = stats->xdp_drops;
 318                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 319                 result->xdp_packets += packets;
 320                 result->xdp_bytes += bytes;
 321                 result->xdp_drops += drops;
 322         }
 323 }
 324
 325 static void veth_get_stats64(struct net_device *dev,
 326                              struct rtnl_link_stats64 *tot)
 327 {
 328         struct veth_priv *priv = netdev_priv(dev);
 329         struct net_device *peer;
 330         struct veth_rq_stats rx;
 331         struct pcpu_lstats tx;
 332
 333         tot->tx_dropped = veth_stats_tx(&tx, dev);
 334         tot->tx_bytes = tx.bytes;
 335         tot->tx_packets = tx.packets;
 336
 337         veth_stats_rx(&rx, dev);
 338         tot->rx_dropped = rx.xdp_drops;
 339         tot->rx_bytes = rx.xdp_bytes;
 340         tot->rx_packets = rx.xdp_packets;
 341
 342         rcu_read_lock();
 343         peer = rcu_dereference(priv->peer);
 344         if (peer) {
 345                 tot->rx_dropped += veth_stats_tx(&tx, peer);
 346                 tot->rx_bytes += tx.bytes;
 347                 tot->rx_packets += tx.packets;
 348
 349                 veth_stats_rx(&rx, peer);
 350                 tot->tx_bytes += rx.xdp_bytes;
 351                 tot->tx_packets += rx.xdp_packets;
 352         }
 353         rcu_read_unlock();
 354 }
 355
 356 /* fake multicast ability */
 357 static void veth_set_multicast_list(struct net_device *dev)
 358 {
 359 }
 360
 361 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 362                                       int buflen)
 363 {
 364         struct sk_buff *skb;
 365
 366         if (!buflen) {
 367                 buflen = SKB_DATA_ALIGN(headroom + len) +
 368                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 369         }
 370         skb = build_skb(head, buflen);
 371         if (!skb)
 372                 return NULL;
 373
 374         skb_reserve(skb, headroom);
 375         skb_put(skb, len);
 376
 377         return skb;
 378 }
 379
 380 static int veth_select_rxq(struct net_device *dev)
 381 {
 382         return smp_processor_id() % dev->real_num_rx_queues;
 383 }
 384
 385 static int veth_xdp_xmit(struct net_device *dev, int n,
 386                          struct xdp_frame **frames, u32 flags)
 387 {
 388         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 389         struct net_device *rcv;
 390         int i, ret, drops = n;
 391         unsigned int max_len;
 392         struct veth_rq *rq;
 393
 394         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) {
 395                 ret = -EINVAL;
 396                 goto drop;
 397         }
 398
 399         rcv = rcu_dereference(priv->peer);
 400         if (unlikely(!rcv)) {
 401                 ret = -ENXIO;
 402                 goto drop;
 403         }
 404
 405         rcv_priv = netdev_priv(rcv);
 406         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 407         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 408          * side. This means an XDP program is loaded on the peer and the peer
 409          * device is up.
 410          */
 411         if (!rcu_access_pointer(rq->xdp_prog)) {
 412                 ret = -ENXIO;
 413                 goto drop;
 414         }
 415
 416         drops = 0;
 417         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 418
 419         spin_lock(&rq->xdp_ring.producer_lock);
 420         for (i = 0; i < n; i++) {
 421                 struct xdp_frame *frame = frames[i];
 422                 void *ptr = veth_xdp_to_ptr(frame);
 423
 424                 if (unlikely(frame->len > max_len ||
 425                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 426                         xdp_return_frame_rx_napi(frame);
 427                         drops++;
 428                 }
 429         }
 430         spin_unlock(&rq->xdp_ring.producer_lock);
 431
 432         if (flags & XDP_XMIT_FLUSH)
 433                 __veth_xdp_flush(rq);
 434
 435         if (likely(!drops))
 436                 return n;
 437
 438         ret = n - drops;
 439 drop:
 440         atomic64_add(drops, &priv->dropped);
 441
 442         return ret;
 443 }
 444
 445 static void veth_xdp_flush(struct net_device *dev)
 446 {
 447         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 448         struct net_device *rcv;
 449         struct veth_rq *rq;
 450
 451         rcu_read_lock();
 452         rcv = rcu_dereference(priv->peer);
 453         if (unlikely(!rcv))
 454                 goto out;
 455
 456         rcv_priv = netdev_priv(rcv);
 457         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 458         /* xdp_ring is initialized on receive side? */
 459         if (unlikely(!rcu_access_pointer(rq->xdp_prog)))
 460                 goto out;
 461
 462         __veth_xdp_flush(rq);
 463 out:
 464         rcu_read_unlock();
 465 }
 466
 467 static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
 468 {
 469         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
 470
 471         if (unlikely(!frame))
 472                 return -EOVERFLOW;
 473
 474         return veth_xdp_xmit(dev, 1, &frame, 0);
 475 }
 476
 477 static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 478                                         struct xdp_frame *frame,
 479                                         unsigned int *xdp_xmit)
 480 {
 481         void *hard_start = frame->data - frame->headroom;
 482         void *head = hard_start - sizeof(struct xdp_frame);
 483         int len = frame->len, delta = 0;
 484         struct xdp_frame orig_frame;
 485         struct bpf_prog *xdp_prog;
 486         unsigned int headroom;
 487         struct sk_buff *skb;
 488
 489         rcu_read_lock();
 490         xdp_prog = rcu_dereference(rq->xdp_prog);
 491         if (likely(xdp_prog)) {
 492                 struct xdp_buff xdp;
 493                 u32 act;
 494
 495                 xdp.data_hard_start = hard_start;
 496                 xdp.data = frame->data;
 497                 xdp.data_end = frame->data + frame->len;
 498                 xdp.data_meta = frame->data - frame->metasize;
 499                 xdp.rxq = &rq->xdp_rxq;
 500
 501                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 502
 503                 switch (act) {
 504                 case XDP_PASS:
 505                         delta = frame->data - xdp.data;
 506                         len = xdp.data_end - xdp.data;
 507                         break;
 508                 case XDP_TX:
 509                         orig_frame = *frame;
 510                         xdp.data_hard_start = head;
 511                         xdp.rxq->mem = frame->mem;
 512                         if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 513                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 514                                 frame = &orig_frame;
 515                                 goto err_xdp;
 516                         }
 517                         *xdp_xmit |= VETH_XDP_TX;
 518                         rcu_read_unlock();
 519                         goto xdp_xmit;
 520                 case XDP_REDIRECT:
 521                         orig_frame = *frame;
 522                         xdp.data_hard_start = head;
 523                         xdp.rxq->mem = frame->mem;
 524                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 525                                 frame = &orig_frame;
 526                                 goto err_xdp;
 527                         }
 528                         *xdp_xmit |= VETH_XDP_REDIR;
 529                         rcu_read_unlock();
 530                         goto xdp_xmit;
 531                 default:
 532                         bpf_warn_invalid_xdp_action(act);
 533                         /* fall through */
 534                 case XDP_ABORTED:
 535                         trace_xdp_exception(rq->dev, xdp_prog, act);
 536                         /* fall through */
 537                 case XDP_DROP:
 538                         goto err_xdp;
 539                 }
 540         }
 541         rcu_read_unlock();
 542
 543         headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
 544         skb = veth_build_skb(head, headroom, len, 0);
 545         if (!skb) {
 546                 xdp_return_frame(frame);
 547                 goto err;
 548         }
 549
 550         xdp_release_frame(frame);
 551         xdp_scrub_frame(frame);
 552         skb->protocol = eth_type_trans(skb, rq->dev);
 553 err:
 554         return skb;
 555 err_xdp:
 556         rcu_read_unlock();
 557         xdp_return_frame(frame);
 558 xdp_xmit:
 559         return NULL;
 560 }
 561
 562 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq, struct sk_buff *skb,
 563                                         unsigned int *xdp_xmit)
 564 {
 565         u32 pktlen, headroom, act, metalen;
 566         void *orig_data, *orig_data_end;
 567         struct bpf_prog *xdp_prog;
 568         int mac_len, delta, off;
 569         struct xdp_buff xdp;
 570
 571         skb_orphan(skb);
 572
 573         rcu_read_lock();
 574         xdp_prog = rcu_dereference(rq->xdp_prog);
 575         if (unlikely(!xdp_prog)) {
 576                 rcu_read_unlock();
 577                 goto out;
 578         }
 579
 580         mac_len = skb->data - skb_mac_header(skb);
 581         pktlen = skb->len + mac_len;
 582         headroom = skb_headroom(skb) - mac_len;
 583
 584         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 585             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 586                 struct sk_buff *nskb;
 587                 int size, head_off;
 588                 void *head, *start;
 589                 struct page *page;
 590
 591                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 592                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 593                 if (size > PAGE_SIZE)
 594                         goto drop;
 595
 596                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 597                 if (!page)
 598                         goto drop;
 599
 600                 head = page_address(page);
 601                 start = head + VETH_XDP_HEADROOM;
 602                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 603                         page_frag_free(head);
 604                         goto drop;
 605                 }
 606
 607                 nskb = veth_build_skb(head,
 608                                       VETH_XDP_HEADROOM + mac_len, skb->len,
 609                                       PAGE_SIZE);
 610                 if (!nskb) {
 611                         page_frag_free(head);
 612                         goto drop;
 613                 }
 614
 615                 skb_copy_header(nskb, skb);
 616                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 617                 skb_headers_offset_update(nskb, head_off);
 618                 consume_skb(skb);
 619                 skb = nskb;
 620         }
 621
 622         xdp.data_hard_start = skb->head;
 623         xdp.data = skb_mac_header(skb);
 624         xdp.data_end = xdp.data + pktlen;
 625         xdp.data_meta = xdp.data;
 626         xdp.rxq = &rq->xdp_rxq;
 627         orig_data = xdp.data;
 628         orig_data_end = xdp.data_end;
 629
 630         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 631
 632         switch (act) {
 633         case XDP_PASS:
 634                 break;
 635         case XDP_TX:
 636                 get_page(virt_to_page(xdp.data));
 637                 consume_skb(skb);
 638                 xdp.rxq->mem = rq->xdp_mem;
 639                 if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 640                         trace_xdp_exception(rq->dev, xdp_prog, act);
 641                         goto err_xdp;
 642                 }
 643                 *xdp_xmit |= VETH_XDP_TX;
 644                 rcu_read_unlock();
 645                 goto xdp_xmit;
 646         case XDP_REDIRECT:
 647                 get_page(virt_to_page(xdp.data));
 648                 consume_skb(skb);
 649                 xdp.rxq->mem = rq->xdp_mem;
 650                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog))
 651                         goto err_xdp;
 652                 *xdp_xmit |= VETH_XDP_REDIR;
 653                 rcu_read_unlock();
 654                 goto xdp_xmit;
 655         default:
 656                 bpf_warn_invalid_xdp_action(act);
 657                 /* fall through */
 658         case XDP_ABORTED:
 659                 trace_xdp_exception(rq->dev, xdp_prog, act);
 660                 /* fall through */
 661         case XDP_DROP:
 662                 goto drop;
 663         }
 664         rcu_read_unlock();
 665
 666         delta = orig_data - xdp.data;
 667         off = mac_len + delta;
 668         if (off > 0)
 669                 __skb_push(skb, off);
 670         else if (off < 0)
 671                 __skb_pull(skb, -off);
 672         skb->mac_header -= delta;
 673         off = xdp.data_end - orig_data_end;
 674         if (off != 0)
 675                 __skb_put(skb, off);
 676         skb->protocol = eth_type_trans(skb, rq->dev);
 677
 678         metalen = xdp.data - xdp.data_meta;
 679         if (metalen)
 680                 skb_metadata_set(skb, metalen);
 681 out:
 682         return skb;
 683 drop:
 684         rcu_read_unlock();
 685         kfree_skb(skb);
 686         return NULL;
 687 err_xdp:
 688         rcu_read_unlock();
 689         page_frag_free(xdp.data);
 690 xdp_xmit:
 691         return NULL;
 692 }
 693
 694 static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit)
 695 {
 696         int i, done = 0, drops = 0, bytes = 0;
 697
 698         for (i = 0; i < budget; i++) {
 699                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 700                 unsigned int xdp_xmit_one = 0;
 701                 struct sk_buff *skb;
 702
 703                 if (!ptr)
 704                         break;
 705
 706                 if (veth_is_xdp_frame(ptr)) {
 707                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 708
 709                         bytes += frame->len;
 710                         skb = veth_xdp_rcv_one(rq, frame, &xdp_xmit_one);
 711                 } else {
 712                         skb = ptr;
 713                         bytes += skb->len;
 714                         skb = veth_xdp_rcv_skb(rq, skb, &xdp_xmit_one);
 715                 }
 716                 *xdp_xmit |= xdp_xmit_one;
 717
 718                 if (skb)
 719                         napi_gro_receive(&rq->xdp_napi, skb);
 720                 else if (!xdp_xmit_one)
 721                         drops++;
 722
 723                 done++;
 724         }
 725
 726         u64_stats_update_begin(&rq->stats.syncp);
 727         rq->stats.xdp_packets += done;
 728         rq->stats.xdp_bytes += bytes;
 729         rq->stats.xdp_drops += drops;
 730         u64_stats_update_end(&rq->stats.syncp);
 731
 732         return done;
 733 }
 734
 735 static int veth_poll(struct napi_struct *napi, int budget)
 736 {
 737         struct veth_rq *rq =
 738                 container_of(napi, struct veth_rq, xdp_napi);
 739         unsigned int xdp_xmit = 0;
 740         int done;
 741
 742         xdp_set_return_frame_no_direct();
 743         done = veth_xdp_rcv(rq, budget, &xdp_xmit);
 744
 745         if (done < budget && napi_complete_done(napi, done)) {
 746                 /* Write rx_notify_masked before reading ptr_ring */
 747                 smp_store_mb(rq->rx_notify_masked, false);
 748                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 749                         rq->rx_notify_masked = true;
 750                         napi_schedule(&rq->xdp_napi);
 751                 }
 752         }
 753
 754         if (xdp_xmit & VETH_XDP_TX)
 755                 veth_xdp_flush(rq->dev);
 756         if (xdp_xmit & VETH_XDP_REDIR)
 757                 xdp_do_flush_map();
 758         xdp_clear_return_frame_no_direct();
 759
 760         return done;
 761 }
 762
 763 static int veth_napi_add(struct net_device *dev)
 764 {
 765         struct veth_priv *priv = netdev_priv(dev);
 766         int err, i;
 767
 768         for (i = 0; i < dev->real_num_rx_queues; i++) {
 769                 struct veth_rq *rq = &priv->rq[i];
 770
 771                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 772                 if (err)
 773                         goto err_xdp_ring;
 774         }
 775
 776         for (i = 0; i < dev->real_num_rx_queues; i++) {
 777                 struct veth_rq *rq = &priv->rq[i];
 778
 779                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 780                 napi_enable(&rq->xdp_napi);
 781         }
 782
 783         return 0;
 784 err_xdp_ring:
 785         for (i--; i >= 0; i--)
 786                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 787
 788         return err;
 789 }
 790
 791 static void veth_napi_del(struct net_device *dev)
 792 {
 793         struct veth_priv *priv = netdev_priv(dev);
 794         int i;
 795
 796         for (i = 0; i < dev->real_num_rx_queues; i++) {
 797                 struct veth_rq *rq = &priv->rq[i];
 798
 799                 napi_disable(&rq->xdp_napi);
 800                 napi_hash_del(&rq->xdp_napi);
 801         }
 802         synchronize_net();
 803
 804         for (i = 0; i < dev->real_num_rx_queues; i++) {
 805                 struct veth_rq *rq = &priv->rq[i];
 806
 807                 netif_napi_del(&rq->xdp_napi);
 808                 rq->rx_notify_masked = false;
 809                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 810         }
 811 }
 812
 813 static int veth_enable_xdp(struct net_device *dev)
 814 {
 815         struct veth_priv *priv = netdev_priv(dev);
 816         int err, i;
 817
 818         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 819                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 820                         struct veth_rq *rq = &priv->rq[i];
 821
 822                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i);
 823                         if (err < 0)
 824                                 goto err_rxq_reg;
 825
 826                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 827                                                          MEM_TYPE_PAGE_SHARED,
 828                                                          NULL);
 829                         if (err < 0)
 830                                 goto err_reg_mem;
 831
 832                         /* Save original mem info as it can be overwritten */
 833                         rq->xdp_mem = rq->xdp_rxq.mem;
 834                 }
 835
 836                 err = veth_napi_add(dev);
 837                 if (err)
 838                         goto err_rxq_reg;
 839         }
 840
 841         for (i = 0; i < dev->real_num_rx_queues; i++)
 842                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 843
 844         return 0;
 845 err_reg_mem:
 846         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 847 err_rxq_reg:
 848         for (i--; i >= 0; i--)
 849                 xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 850
 851         return err;
 852 }
 853
 854 static void veth_disable_xdp(struct net_device *dev)
 855 {
 856         struct veth_priv *priv = netdev_priv(dev);
 857         int i;
 858
 859         for (i = 0; i < dev->real_num_rx_queues; i++)
 860                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 861         veth_napi_del(dev);
 862         for (i = 0; i < dev->real_num_rx_queues; i++) {
 863                 struct veth_rq *rq = &priv->rq[i];
 864
 865                 rq->xdp_rxq.mem = rq->xdp_mem;
 866                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 867         }
 868 }
 869
 870 static int veth_open(struct net_device *dev)
 871 {
 872         struct veth_priv *priv = netdev_priv(dev);
 873         struct net_device *peer = rtnl_dereference(priv->peer);
 874         int err;
 875
 876         if (!peer)
 877                 return -ENOTCONN;
 878
 879         if (priv->_xdp_prog) {
 880                 err = veth_enable_xdp(dev);
 881                 if (err)
 882                         return err;
 883         }
 884
 885         if (peer->flags & IFF_UP) {
 886                 netif_carrier_on(dev);
 887                 netif_carrier_on(peer);
 888         }
 889
 890         return 0;
 891 }
 892
 893 static int veth_close(struct net_device *dev)
 894 {
 895         struct veth_priv *priv = netdev_priv(dev);
 896         struct net_device *peer = rtnl_dereference(priv->peer);
 897
 898         netif_carrier_off(dev);
 899         if (peer)
 900                 netif_carrier_off(peer);
 901
 902         if (priv->_xdp_prog)
 903                 veth_disable_xdp(dev);
 904
 905         return 0;
 906 }
 907
 908 static int is_valid_veth_mtu(int mtu)
 909 {
 910         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
 911 }
 912
 913 static int veth_alloc_queues(struct net_device *dev)
 914 {
 915         struct veth_priv *priv = netdev_priv(dev);
 916         int i;
 917
 918         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
 919         if (!priv->rq)
 920                 return -ENOMEM;
 921
 922         for (i = 0; i < dev->num_rx_queues; i++) {
 923                 priv->rq[i].dev = dev;
 924                 u64_stats_init(&priv->rq[i].stats.syncp);
 925         }
 926
 927         return 0;
 928 }
 929
 930 static void veth_free_queues(struct net_device *dev)
 931 {
 932         struct veth_priv *priv = netdev_priv(dev);
 933
 934         kfree(priv->rq);
 935 }
 936
 937 static int veth_dev_init(struct net_device *dev)
 938 {
 939         int err;
 940
 941         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
 942         if (!dev->lstats)
 943                 return -ENOMEM;
 944
 945         err = veth_alloc_queues(dev);
 946         if (err) {
 947                 free_percpu(dev->lstats);
 948                 return err;
 949         }
 950
 951         return 0;
 952 }
 953
 954 static void veth_dev_free(struct net_device *dev)
 955 {
 956         veth_free_queues(dev);
 957         free_percpu(dev->lstats);
 958 }
 959
 960 #ifdef CONFIG_NET_POLL_CONTROLLER
 961 static void veth_poll_controller(struct net_device *dev)
 962 {
 963         /* veth only receives frames when its peer sends one
 964          * Since it has nothing to do with disabling irqs, we are guaranteed
 965          * never to have pending data when we poll for it so
 966          * there is nothing to do here.
 967          *
 968          * We need this though so netpoll recognizes us as an interface that
 969          * supports polling, which enables bridge devices in virt setups to
 970          * still use netconsole
 971          */
 972 }
 973 #endif  /* CONFIG_NET_POLL_CONTROLLER */
 974
 975 static int veth_get_iflink(const struct net_device *dev)
 976 {
 977         struct veth_priv *priv = netdev_priv(dev);
 978         struct net_device *peer;
 979         int iflink;
 980
 981         rcu_read_lock();
 982         peer = rcu_dereference(priv->peer);
 983         iflink = peer ? peer->ifindex : 0;
 984         rcu_read_unlock();
 985
 986         return iflink;
 987 }
 988
 989 static netdev_features_t veth_fix_features(struct net_device *dev,
 990                                            netdev_features_t features)
 991 {
 992         struct veth_priv *priv = netdev_priv(dev);
 993         struct net_device *peer;
 994
 995         peer = rtnl_dereference(priv->peer);
 996         if (peer) {
 997                 struct veth_priv *peer_priv = netdev_priv(peer);
 998
 999                 if (peer_priv->_xdp_prog)
1000                         features &= ~NETIF_F_GSO_SOFTWARE;
1001         }
1002
1003         return features;
1004 }
1005
1006 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1007 {
1008         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1009         struct net_device *peer;
1010
1011         if (new_hr < 0)
1012                 new_hr = 0;
1013
1014         rcu_read_lock();
1015         peer = rcu_dereference(priv->peer);
1016         if (unlikely(!peer))
1017                 goto out;
1018
1019         peer_priv = netdev_priv(peer);
1020         priv->requested_headroom = new_hr;
1021         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1022         dev->needed_headroom = new_hr;
1023         peer->needed_headroom = new_hr;
1024
1025 out:
1026         rcu_read_unlock();
1027 }
1028
1029 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1030                         struct netlink_ext_ack *extack)
1031 {
1032         struct veth_priv *priv = netdev_priv(dev);
1033         struct bpf_prog *old_prog;
1034         struct net_device *peer;
1035         unsigned int max_mtu;
1036         int err;
1037
1038         old_prog = priv->_xdp_prog;
1039         priv->_xdp_prog = prog;
1040         peer = rtnl_dereference(priv->peer);
1041
1042         if (prog) {
1043                 if (!peer) {
1044                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1045                         err = -ENOTCONN;
1046                         goto err;
1047                 }
1048
1049                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
1050                           peer->hard_header_len -
1051                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1052                 if (peer->mtu > max_mtu) {
1053                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1054                         err = -ERANGE;
1055                         goto err;
1056                 }
1057
1058                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1059                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1060                         err = -ENOSPC;
1061                         goto err;
1062                 }
1063
1064                 if (dev->flags & IFF_UP) {
1065                         err = veth_enable_xdp(dev);
1066                         if (err) {
1067                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1068                                 goto err;
1069                         }
1070                 }
1071
1072                 if (!old_prog) {
1073                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1074                         peer->max_mtu = max_mtu;
1075                 }
1076         }
1077
1078         if (old_prog) {
1079                 if (!prog) {
1080                         if (dev->flags & IFF_UP)
1081                                 veth_disable_xdp(dev);
1082
1083                         if (peer) {
1084                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1085                                 peer->max_mtu = ETH_MAX_MTU;
1086                         }
1087                 }
1088                 bpf_prog_put(old_prog);
1089         }
1090
1091         if ((!!old_prog ^ !!prog) && peer)
1092                 netdev_update_features(peer);
1093
1094         return 0;
1095 err:
1096         priv->_xdp_prog = old_prog;
1097
1098         return err;
1099 }
1100
1101 static u32 veth_xdp_query(struct net_device *dev)
1102 {
1103         struct veth_priv *priv = netdev_priv(dev);
1104         const struct bpf_prog *xdp_prog;
1105
1106         xdp_prog = priv->_xdp_prog;
1107         if (xdp_prog)
1108                 return xdp_prog->aux->id;
1109
1110         return 0;
1111 }
1112
1113 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1114 {
1115         switch (xdp->command) {
1116         case XDP_SETUP_PROG:
1117                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1118         case XDP_QUERY_PROG:
1119                 xdp->prog_id = veth_xdp_query(dev);
1120                 return 0;
1121         default:
1122                 return -EINVAL;
1123         }
1124 }
1125
1126 static const struct net_device_ops veth_netdev_ops = {
1127         .ndo_init            = veth_dev_init,
1128         .ndo_open            = veth_open,
1129         .ndo_stop            = veth_close,
1130         .ndo_start_xmit      = veth_xmit,
1131         .ndo_get_stats64     = veth_get_stats64,
1132         .ndo_set_rx_mode     = veth_set_multicast_list,
1133         .ndo_set_mac_address = eth_mac_addr,
1134 #ifdef CONFIG_NET_POLL_CONTROLLER
1135         .ndo_poll_controller    = veth_poll_controller,
1136 #endif
1137         .ndo_get_iflink         = veth_get_iflink,
1138         .ndo_fix_features       = veth_fix_features,
1139         .ndo_features_check     = passthru_features_check,
1140         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1141         .ndo_bpf                = veth_xdp,
1142         .ndo_xdp_xmit           = veth_xdp_xmit,
1143 };
1144
1145 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1146                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1147                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1148                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1149                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1150
1151 static void veth_setup(struct net_device *dev)
1152 {
1153         ether_setup(dev);
1154
1155         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1156         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1157         dev->priv_flags |= IFF_NO_QUEUE;
1158         dev->priv_flags |= IFF_PHONY_HEADROOM;
1159
1160         dev->netdev_ops = &veth_netdev_ops;
1161         dev->ethtool_ops = &veth_ethtool_ops;
1162         dev->features |= NETIF_F_LLTX;
1163         dev->features |= VETH_FEATURES;
1164         dev->vlan_features = dev->features &
1165                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1166                                NETIF_F_HW_VLAN_STAG_TX |
1167                                NETIF_F_HW_VLAN_CTAG_RX |
1168                                NETIF_F_HW_VLAN_STAG_RX);
1169         dev->needs_free_netdev = true;
1170         dev->priv_destructor = veth_dev_free;
1171         dev->max_mtu = ETH_MAX_MTU;
1172
1173         dev->hw_features = VETH_FEATURES;
1174         dev->hw_enc_features = VETH_FEATURES;
1175         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1176 }
1177
1178 /*
1179  * netlink interface
1180  */
1181
1182 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1183                          struct netlink_ext_ack *extack)
1184 {
1185         if (tb[IFLA_ADDRESS]) {
1186                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1187                         return -EINVAL;
1188                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1189                         return -EADDRNOTAVAIL;
1190         }
1191         if (tb[IFLA_MTU]) {
1192                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1193                         return -EINVAL;
1194         }
1195         return 0;
1196 }
1197
1198 static struct rtnl_link_ops veth_link_ops;
1199
1200 static int veth_newlink(struct net *src_net, struct net_device *dev,
1201                         struct nlattr *tb[], struct nlattr *data[],
1202                         struct netlink_ext_ack *extack)
1203 {
1204         int err;
1205         struct net_device *peer;
1206         struct veth_priv *priv;
1207         char ifname[IFNAMSIZ];
1208         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1209         unsigned char name_assign_type;
1210         struct ifinfomsg *ifmp;
1211         struct net *net;
1212
1213         /*
1214          * create and register peer first
1215          */
1216         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1217                 struct nlattr *nla_peer;
1218
1219                 nla_peer = data[VETH_INFO_PEER];
1220                 ifmp = nla_data(nla_peer);
1221                 err = rtnl_nla_parse_ifla(peer_tb,
1222                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1223                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1224                                           NULL);
1225                 if (err < 0)
1226                         return err;
1227
1228                 err = veth_validate(peer_tb, NULL, extack);
1229                 if (err < 0)
1230                         return err;
1231
1232                 tbp = peer_tb;
1233         } else {
1234                 ifmp = NULL;
1235                 tbp = tb;
1236         }
1237
1238         if (ifmp && tbp[IFLA_IFNAME]) {
1239                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1240                 name_assign_type = NET_NAME_USER;
1241         } else {
1242                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1243                 name_assign_type = NET_NAME_ENUM;
1244         }
1245
1246         net = rtnl_link_get_net(src_net, tbp);
1247         if (IS_ERR(net))
1248                 return PTR_ERR(net);
1249
1250         peer = rtnl_create_link(net, ifname, name_assign_type,
1251                                 &veth_link_ops, tbp, extack);
1252         if (IS_ERR(peer)) {
1253                 put_net(net);
1254                 return PTR_ERR(peer);
1255         }
1256
1257         if (!ifmp || !tbp[IFLA_ADDRESS])
1258                 eth_hw_addr_random(peer);
1259
1260         if (ifmp && (dev->ifindex != 0))
1261                 peer->ifindex = ifmp->ifi_index;
1262
1263         peer->gso_max_size = dev->gso_max_size;
1264         peer->gso_max_segs = dev->gso_max_segs;
1265
1266         err = register_netdevice(peer);
1267         put_net(net);
1268         net = NULL;
1269         if (err < 0)
1270                 goto err_register_peer;
1271
1272         netif_carrier_off(peer);
1273
1274         err = rtnl_configure_link(peer, ifmp);
1275         if (err < 0)
1276                 goto err_configure_peer;
1277
1278         /*
1279          * register dev last
1280          *
1281          * note, that since we've registered new device the dev's name
1282          * should be re-allocated
1283          */
1284
1285         if (tb[IFLA_ADDRESS] == NULL)
1286                 eth_hw_addr_random(dev);
1287
1288         if (tb[IFLA_IFNAME])
1289                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1290         else
1291                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1292
1293         err = register_netdevice(dev);
1294         if (err < 0)
1295                 goto err_register_dev;
1296
1297         netif_carrier_off(dev);
1298
1299         /*
1300          * tie the deviced together
1301          */
1302
1303         priv = netdev_priv(dev);
1304         rcu_assign_pointer(priv->peer, peer);
1305
1306         priv = netdev_priv(peer);
1307         rcu_assign_pointer(priv->peer, dev);
1308
1309         return 0;
1310
1311 err_register_dev:
1312         /* nothing to do */
1313 err_configure_peer:
1314         unregister_netdevice(peer);
1315         return err;
1316
1317 err_register_peer:
1318         free_netdev(peer);
1319         return err;
1320 }
1321
1322 static void veth_dellink(struct net_device *dev, struct list_head *head)
1323 {
1324         struct veth_priv *priv;
1325         struct net_device *peer;
1326
1327         priv = netdev_priv(dev);
1328         peer = rtnl_dereference(priv->peer);
1329
1330         /* Note : dellink() is called from default_device_exit_batch(),
1331          * before a rcu_synchronize() point. The devices are guaranteed
1332          * not being freed before one RCU grace period.
1333          */
1334         RCU_INIT_POINTER(priv->peer, NULL);
1335         unregister_netdevice_queue(dev, head);
1336
1337         if (peer) {
1338                 priv = netdev_priv(peer);
1339                 RCU_INIT_POINTER(priv->peer, NULL);
1340                 unregister_netdevice_queue(peer, head);
1341         }
1342 }
1343
1344 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1345         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1346 };
1347
1348 static struct net *veth_get_link_net(const struct net_device *dev)
1349 {
1350         struct veth_priv *priv = netdev_priv(dev);
1351         struct net_device *peer = rtnl_dereference(priv->peer);
1352
1353         return peer ? dev_net(peer) : dev_net(dev);
1354 }
1355
1356 static struct rtnl_link_ops veth_link_ops = {
1357         .kind           = DRV_NAME,
1358         .priv_size      = sizeof(struct veth_priv),
1359         .setup          = veth_setup,
1360         .validate       = veth_validate,
1361         .newlink        = veth_newlink,
1362         .dellink        = veth_dellink,
1363         .policy         = veth_policy,
1364         .maxtype        = VETH_INFO_MAX,
1365         .get_link_net   = veth_get_link_net,
1366 };
1367
1368 /*
1369  * init/fini
1370  */
1371
1372 static __init int veth_init(void)
1373 {
1374         return rtnl_link_register(&veth_link_ops);
1375 }
1376
1377 static __exit void veth_exit(void)
1378 {
1379         rtnl_link_unregister(&veth_link_ops);
1380 }
1381
1382 module_init(veth_init);
1383 module_exit(veth_exit);
1384
1385 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1386 MODULE_LICENSE("GPL v2");
1387 MODULE_ALIAS_RTNL_LINK(DRV_NAME);