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 #define VETH_XDP_TX_BULK_SIZE   16
  42
  43 struct veth_rq_stats {
  44         u64                     xdp_packets;
  45         u64                     xdp_bytes;
  46         u64                     xdp_drops;
  47         struct u64_stats_sync   syncp;
  48 };
  49
  50 struct veth_rq {
  51         struct napi_struct      xdp_napi;
  52         struct net_device       *dev;
  53         struct bpf_prog __rcu   *xdp_prog;
  54         struct xdp_mem_info     xdp_mem;
  55         struct veth_rq_stats    stats;
  56         bool                    rx_notify_masked;
  57         struct ptr_ring         xdp_ring;
  58         struct xdp_rxq_info     xdp_rxq;
  59 };
  60
  61 struct veth_priv {
  62         struct net_device __rcu *peer;
  63         atomic64_t              dropped;
  64         struct bpf_prog         *_xdp_prog;
  65         struct veth_rq          *rq;
  66         unsigned int            requested_headroom;
  67 };
  68
  69 struct veth_xdp_tx_bq {
  70         struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
  71         unsigned int count;
  72 };
  73
  74 /*
  75  * ethtool interface
  76  */
  77
  78 struct veth_q_stat_desc {
  79         char    desc[ETH_GSTRING_LEN];
  80         size_t  offset;
  81 };
  82
  83 #define VETH_RQ_STAT(m) offsetof(struct veth_rq_stats, m)
  84
  85 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  86         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  87         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  88         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
  89 };
  90
  91 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
  92
  93 static struct {
  94         const char string[ETH_GSTRING_LEN];
  95 } ethtool_stats_keys[] = {
  96         { "peer_ifindex" },
  97 };
  98
  99 static int veth_get_link_ksettings(struct net_device *dev,
 100                                    struct ethtool_link_ksettings *cmd)
 101 {
 102         cmd->base.speed         = SPEED_10000;
 103         cmd->base.duplex        = DUPLEX_FULL;
 104         cmd->base.port          = PORT_TP;
 105         cmd->base.autoneg       = AUTONEG_DISABLE;
 106         return 0;
 107 }
 108
 109 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 110 {
 111         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 112         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 113 }
 114
 115 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 116 {
 117         char *p = (char *)buf;
 118         int i, j;
 119
 120         switch(stringset) {
 121         case ETH_SS_STATS:
 122                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 123                 p += sizeof(ethtool_stats_keys);
 124                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 125                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 126                                 snprintf(p, ETH_GSTRING_LEN,
 127                                          "rx_queue_%u_%.11s",
 128                                          i, veth_rq_stats_desc[j].desc);
 129                                 p += ETH_GSTRING_LEN;
 130                         }
 131                 }
 132                 break;
 133         }
 134 }
 135
 136 static int veth_get_sset_count(struct net_device *dev, int sset)
 137 {
 138         switch (sset) {
 139         case ETH_SS_STATS:
 140                 return ARRAY_SIZE(ethtool_stats_keys) +
 141                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues;
 142         default:
 143                 return -EOPNOTSUPP;
 144         }
 145 }
 146
 147 static void veth_get_ethtool_stats(struct net_device *dev,
 148                 struct ethtool_stats *stats, u64 *data)
 149 {
 150         struct veth_priv *priv = netdev_priv(dev);
 151         struct net_device *peer = rtnl_dereference(priv->peer);
 152         int i, j, idx;
 153
 154         data[0] = peer ? peer->ifindex : 0;
 155         idx = 1;
 156         for (i = 0; i < dev->real_num_rx_queues; i++) {
 157                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 158                 const void *stats_base = (void *)rq_stats;
 159                 unsigned int start;
 160                 size_t offset;
 161
 162                 do {
 163                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 164                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 165                                 offset = veth_rq_stats_desc[j].offset;
 166                                 data[idx + j] = *(u64 *)(stats_base + offset);
 167                         }
 168                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 169                 idx += VETH_RQ_STATS_LEN;
 170         }
 171 }
 172
 173 static const struct ethtool_ops veth_ethtool_ops = {
 174         .get_drvinfo            = veth_get_drvinfo,
 175         .get_link               = ethtool_op_get_link,
 176         .get_strings            = veth_get_strings,
 177         .get_sset_count         = veth_get_sset_count,
 178         .get_ethtool_stats      = veth_get_ethtool_stats,
 179         .get_link_ksettings     = veth_get_link_ksettings,
 180         .get_ts_info            = ethtool_op_get_ts_info,
 181 };
 182
 183 /* general routines */
 184
 185 static bool veth_is_xdp_frame(void *ptr)
 186 {
 187         return (unsigned long)ptr & VETH_XDP_FLAG;
 188 }
 189
 190 static void *veth_ptr_to_xdp(void *ptr)
 191 {
 192         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 193 }
 194
 195 static void *veth_xdp_to_ptr(void *ptr)
 196 {
 197         return (void *)((unsigned long)ptr | VETH_XDP_FLAG);
 198 }
 199
 200 static void veth_ptr_free(void *ptr)
 201 {
 202         if (veth_is_xdp_frame(ptr))
 203                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 204         else
 205                 kfree_skb(ptr);
 206 }
 207
 208 static void __veth_xdp_flush(struct veth_rq *rq)
 209 {
 210         /* Write ptr_ring before reading rx_notify_masked */
 211         smp_mb();
 212         if (!rq->rx_notify_masked) {
 213                 rq->rx_notify_masked = true;
 214                 napi_schedule(&rq->xdp_napi);
 215         }
 216 }
 217
 218 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 219 {
 220         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 221                 dev_kfree_skb_any(skb);
 222                 return NET_RX_DROP;
 223         }
 224
 225         return NET_RX_SUCCESS;
 226 }
 227
 228 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 229                             struct veth_rq *rq, bool xdp)
 230 {
 231         return __dev_forward_skb(dev, skb) ?: xdp ?
 232                 veth_xdp_rx(rq, skb) :
 233                 netif_rx(skb);
 234 }
 235
 236 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 237 {
 238         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 239         struct veth_rq *rq = NULL;
 240         struct net_device *rcv;
 241         int length = skb->len;
 242         bool rcv_xdp = false;
 243         int rxq;
 244
 245         rcu_read_lock();
 246         rcv = rcu_dereference(priv->peer);
 247         if (unlikely(!rcv)) {
 248                 kfree_skb(skb);
 249                 goto drop;
 250         }
 251
 252         rcv_priv = netdev_priv(rcv);
 253         rxq = skb_get_queue_mapping(skb);
 254         if (rxq < rcv->real_num_rx_queues) {
 255                 rq = &rcv_priv->rq[rxq];
 256                 rcv_xdp = rcu_access_pointer(rq->xdp_prog);
 257                 if (rcv_xdp)
 258                         skb_record_rx_queue(skb, rxq);
 259         }
 260
 261         skb_tx_timestamp(skb);
 262         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 263                 if (!rcv_xdp)
 264                         dev_lstats_add(dev, length);
 265         } else {
 266 drop:
 267                 atomic64_inc(&priv->dropped);
 268         }
 269
 270         if (rcv_xdp)
 271                 __veth_xdp_flush(rq);
 272
 273         rcu_read_unlock();
 274
 275         return NETDEV_TX_OK;
 276 }
 277
 278 static u64 veth_stats_tx(struct net_device *dev, u64 *packets, u64 *bytes)
 279 {
 280         struct veth_priv *priv = netdev_priv(dev);
 281
 282         dev_lstats_read(dev, packets, bytes);
 283         return atomic64_read(&priv->dropped);
 284 }
 285
 286 static void veth_stats_rx(struct veth_rq_stats *result, struct net_device *dev)
 287 {
 288         struct veth_priv *priv = netdev_priv(dev);
 289         int i;
 290
 291         result->xdp_packets = 0;
 292         result->xdp_bytes = 0;
 293         result->xdp_drops = 0;
 294         for (i = 0; i < dev->num_rx_queues; i++) {
 295                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 296                 u64 packets, bytes, drops;
 297                 unsigned int start;
 298
 299                 do {
 300                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 301                         packets = stats->xdp_packets;
 302                         bytes = stats->xdp_bytes;
 303                         drops = stats->xdp_drops;
 304                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 305                 result->xdp_packets += packets;
 306                 result->xdp_bytes += bytes;
 307                 result->xdp_drops += drops;
 308         }
 309 }
 310
 311 static void veth_get_stats64(struct net_device *dev,
 312                              struct rtnl_link_stats64 *tot)
 313 {
 314         struct veth_priv *priv = netdev_priv(dev);
 315         struct net_device *peer;
 316         struct veth_rq_stats rx;
 317         u64 packets, bytes;
 318
 319         tot->tx_dropped = veth_stats_tx(dev, &packets, &bytes);
 320         tot->tx_bytes = bytes;
 321         tot->tx_packets = packets;
 322
 323         veth_stats_rx(&rx, dev);
 324         tot->rx_dropped = rx.xdp_drops;
 325         tot->rx_bytes = rx.xdp_bytes;
 326         tot->rx_packets = rx.xdp_packets;
 327
 328         rcu_read_lock();
 329         peer = rcu_dereference(priv->peer);
 330         if (peer) {
 331                 tot->rx_dropped += veth_stats_tx(peer, &packets, &bytes);
 332                 tot->rx_bytes += bytes;
 333                 tot->rx_packets += packets;
 334
 335                 veth_stats_rx(&rx, peer);
 336                 tot->tx_bytes += rx.xdp_bytes;
 337                 tot->tx_packets += rx.xdp_packets;
 338         }
 339         rcu_read_unlock();
 340 }
 341
 342 /* fake multicast ability */
 343 static void veth_set_multicast_list(struct net_device *dev)
 344 {
 345 }
 346
 347 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 348                                       int buflen)
 349 {
 350         struct sk_buff *skb;
 351
 352         if (!buflen) {
 353                 buflen = SKB_DATA_ALIGN(headroom + len) +
 354                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 355         }
 356         skb = build_skb(head, buflen);
 357         if (!skb)
 358                 return NULL;
 359
 360         skb_reserve(skb, headroom);
 361         skb_put(skb, len);
 362
 363         return skb;
 364 }
 365
 366 static int veth_select_rxq(struct net_device *dev)
 367 {
 368         return smp_processor_id() % dev->real_num_rx_queues;
 369 }
 370
 371 static int veth_xdp_xmit(struct net_device *dev, int n,
 372                          struct xdp_frame **frames, u32 flags)
 373 {
 374         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 375         struct net_device *rcv;
 376         int i, ret, drops = n;
 377         unsigned int max_len;
 378         struct veth_rq *rq;
 379
 380         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) {
 381                 ret = -EINVAL;
 382                 goto drop;
 383         }
 384
 385         rcv = rcu_dereference(priv->peer);
 386         if (unlikely(!rcv)) {
 387                 ret = -ENXIO;
 388                 goto drop;
 389         }
 390
 391         rcv_priv = netdev_priv(rcv);
 392         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 393         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 394          * side. This means an XDP program is loaded on the peer and the peer
 395          * device is up.
 396          */
 397         if (!rcu_access_pointer(rq->xdp_prog)) {
 398                 ret = -ENXIO;
 399                 goto drop;
 400         }
 401
 402         drops = 0;
 403         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 404
 405         spin_lock(&rq->xdp_ring.producer_lock);
 406         for (i = 0; i < n; i++) {
 407                 struct xdp_frame *frame = frames[i];
 408                 void *ptr = veth_xdp_to_ptr(frame);
 409
 410                 if (unlikely(frame->len > max_len ||
 411                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 412                         xdp_return_frame_rx_napi(frame);
 413                         drops++;
 414                 }
 415         }
 416         spin_unlock(&rq->xdp_ring.producer_lock);
 417
 418         if (flags & XDP_XMIT_FLUSH)
 419                 __veth_xdp_flush(rq);
 420
 421         if (likely(!drops))
 422                 return n;
 423
 424         ret = n - drops;
 425 drop:
 426         atomic64_add(drops, &priv->dropped);
 427
 428         return ret;
 429 }
 430
 431 static void veth_xdp_flush_bq(struct net_device *dev, struct veth_xdp_tx_bq *bq)
 432 {
 433         int sent, i, err = 0;
 434
 435         sent = veth_xdp_xmit(dev, bq->count, bq->q, 0);
 436         if (sent < 0) {
 437                 err = sent;
 438                 sent = 0;
 439                 for (i = 0; i < bq->count; i++)
 440                         xdp_return_frame(bq->q[i]);
 441         }
 442         trace_xdp_bulk_tx(dev, sent, bq->count - sent, err);
 443
 444         bq->count = 0;
 445 }
 446
 447 static void veth_xdp_flush(struct net_device *dev, struct veth_xdp_tx_bq *bq)
 448 {
 449         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 450         struct net_device *rcv;
 451         struct veth_rq *rq;
 452
 453         rcu_read_lock();
 454         veth_xdp_flush_bq(dev, bq);
 455         rcv = rcu_dereference(priv->peer);
 456         if (unlikely(!rcv))
 457                 goto out;
 458
 459         rcv_priv = netdev_priv(rcv);
 460         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 461         /* xdp_ring is initialized on receive side? */
 462         if (unlikely(!rcu_access_pointer(rq->xdp_prog)))
 463                 goto out;
 464
 465         __veth_xdp_flush(rq);
 466 out:
 467         rcu_read_unlock();
 468 }
 469
 470 static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp,
 471                        struct veth_xdp_tx_bq *bq)
 472 {
 473         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
 474
 475         if (unlikely(!frame))
 476                 return -EOVERFLOW;
 477
 478         if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
 479                 veth_xdp_flush_bq(dev, bq);
 480
 481         bq->q[bq->count++] = frame;
 482
 483         return 0;
 484 }
 485
 486 static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 487                                         struct xdp_frame *frame,
 488                                         unsigned int *xdp_xmit,
 489                                         struct veth_xdp_tx_bq *bq)
 490 {
 491         void *hard_start = frame->data - frame->headroom;
 492         void *head = hard_start - sizeof(struct xdp_frame);
 493         int len = frame->len, delta = 0;
 494         struct xdp_frame orig_frame;
 495         struct bpf_prog *xdp_prog;
 496         unsigned int headroom;
 497         struct sk_buff *skb;
 498
 499         rcu_read_lock();
 500         xdp_prog = rcu_dereference(rq->xdp_prog);
 501         if (likely(xdp_prog)) {
 502                 struct xdp_buff xdp;
 503                 u32 act;
 504
 505                 xdp.data_hard_start = hard_start;
 506                 xdp.data = frame->data;
 507                 xdp.data_end = frame->data + frame->len;
 508                 xdp.data_meta = frame->data - frame->metasize;
 509                 xdp.rxq = &rq->xdp_rxq;
 510
 511                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 512
 513                 switch (act) {
 514                 case XDP_PASS:
 515                         delta = frame->data - xdp.data;
 516                         len = xdp.data_end - xdp.data;
 517                         break;
 518                 case XDP_TX:
 519                         orig_frame = *frame;
 520                         xdp.data_hard_start = head;
 521                         xdp.rxq->mem = frame->mem;
 522                         if (unlikely(veth_xdp_tx(rq->dev, &xdp, bq) < 0)) {
 523                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 524                                 frame = &orig_frame;
 525                                 goto err_xdp;
 526                         }
 527                         *xdp_xmit |= VETH_XDP_TX;
 528                         rcu_read_unlock();
 529                         goto xdp_xmit;
 530                 case XDP_REDIRECT:
 531                         orig_frame = *frame;
 532                         xdp.data_hard_start = head;
 533                         xdp.rxq->mem = frame->mem;
 534                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 535                                 frame = &orig_frame;
 536                                 goto err_xdp;
 537                         }
 538                         *xdp_xmit |= VETH_XDP_REDIR;
 539                         rcu_read_unlock();
 540                         goto xdp_xmit;
 541                 default:
 542                         bpf_warn_invalid_xdp_action(act);
 543                         /* fall through */
 544                 case XDP_ABORTED:
 545                         trace_xdp_exception(rq->dev, xdp_prog, act);
 546                         /* fall through */
 547                 case XDP_DROP:
 548                         goto err_xdp;
 549                 }
 550         }
 551         rcu_read_unlock();
 552
 553         headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
 554         skb = veth_build_skb(head, headroom, len, 0);
 555         if (!skb) {
 556                 xdp_return_frame(frame);
 557                 goto err;
 558         }
 559
 560         xdp_release_frame(frame);
 561         xdp_scrub_frame(frame);
 562         skb->protocol = eth_type_trans(skb, rq->dev);
 563 err:
 564         return skb;
 565 err_xdp:
 566         rcu_read_unlock();
 567         xdp_return_frame(frame);
 568 xdp_xmit:
 569         return NULL;
 570 }
 571
 572 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq, struct sk_buff *skb,
 573                                         unsigned int *xdp_xmit,
 574                                         struct veth_xdp_tx_bq *bq)
 575 {
 576         u32 pktlen, headroom, act, metalen;
 577         void *orig_data, *orig_data_end;
 578         struct bpf_prog *xdp_prog;
 579         int mac_len, delta, off;
 580         struct xdp_buff xdp;
 581
 582         skb_orphan(skb);
 583
 584         rcu_read_lock();
 585         xdp_prog = rcu_dereference(rq->xdp_prog);
 586         if (unlikely(!xdp_prog)) {
 587                 rcu_read_unlock();
 588                 goto out;
 589         }
 590
 591         mac_len = skb->data - skb_mac_header(skb);
 592         pktlen = skb->len + mac_len;
 593         headroom = skb_headroom(skb) - mac_len;
 594
 595         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 596             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 597                 struct sk_buff *nskb;
 598                 int size, head_off;
 599                 void *head, *start;
 600                 struct page *page;
 601
 602                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 603                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 604                 if (size > PAGE_SIZE)
 605                         goto drop;
 606
 607                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 608                 if (!page)
 609                         goto drop;
 610
 611                 head = page_address(page);
 612                 start = head + VETH_XDP_HEADROOM;
 613                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 614                         page_frag_free(head);
 615                         goto drop;
 616                 }
 617
 618                 nskb = veth_build_skb(head,
 619                                       VETH_XDP_HEADROOM + mac_len, skb->len,
 620                                       PAGE_SIZE);
 621                 if (!nskb) {
 622                         page_frag_free(head);
 623                         goto drop;
 624                 }
 625
 626                 skb_copy_header(nskb, skb);
 627                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 628                 skb_headers_offset_update(nskb, head_off);
 629                 consume_skb(skb);
 630                 skb = nskb;
 631         }
 632
 633         xdp.data_hard_start = skb->head;
 634         xdp.data = skb_mac_header(skb);
 635         xdp.data_end = xdp.data + pktlen;
 636         xdp.data_meta = xdp.data;
 637         xdp.rxq = &rq->xdp_rxq;
 638         orig_data = xdp.data;
 639         orig_data_end = xdp.data_end;
 640
 641         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 642
 643         switch (act) {
 644         case XDP_PASS:
 645                 break;
 646         case XDP_TX:
 647                 get_page(virt_to_page(xdp.data));
 648                 consume_skb(skb);
 649                 xdp.rxq->mem = rq->xdp_mem;
 650                 if (unlikely(veth_xdp_tx(rq->dev, &xdp, bq) < 0)) {
 651                         trace_xdp_exception(rq->dev, xdp_prog, act);
 652                         goto err_xdp;
 653                 }
 654                 *xdp_xmit |= VETH_XDP_TX;
 655                 rcu_read_unlock();
 656                 goto xdp_xmit;
 657         case XDP_REDIRECT:
 658                 get_page(virt_to_page(xdp.data));
 659                 consume_skb(skb);
 660                 xdp.rxq->mem = rq->xdp_mem;
 661                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog))
 662                         goto err_xdp;
 663                 *xdp_xmit |= VETH_XDP_REDIR;
 664                 rcu_read_unlock();
 665                 goto xdp_xmit;
 666         default:
 667                 bpf_warn_invalid_xdp_action(act);
 668                 /* fall through */
 669         case XDP_ABORTED:
 670                 trace_xdp_exception(rq->dev, xdp_prog, act);
 671                 /* fall through */
 672         case XDP_DROP:
 673                 goto drop;
 674         }
 675         rcu_read_unlock();
 676
 677         delta = orig_data - xdp.data;
 678         off = mac_len + delta;
 679         if (off > 0)
 680                 __skb_push(skb, off);
 681         else if (off < 0)
 682                 __skb_pull(skb, -off);
 683         skb->mac_header -= delta;
 684         off = xdp.data_end - orig_data_end;
 685         if (off != 0)
 686                 __skb_put(skb, off);
 687         skb->protocol = eth_type_trans(skb, rq->dev);
 688
 689         metalen = xdp.data - xdp.data_meta;
 690         if (metalen)
 691                 skb_metadata_set(skb, metalen);
 692 out:
 693         return skb;
 694 drop:
 695         rcu_read_unlock();
 696         kfree_skb(skb);
 697         return NULL;
 698 err_xdp:
 699         rcu_read_unlock();
 700         page_frag_free(xdp.data);
 701 xdp_xmit:
 702         return NULL;
 703 }
 704
 705 static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit,
 706                         struct veth_xdp_tx_bq *bq)
 707 {
 708         int i, done = 0, drops = 0, bytes = 0;
 709
 710         for (i = 0; i < budget; i++) {
 711                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 712                 unsigned int xdp_xmit_one = 0;
 713                 struct sk_buff *skb;
 714
 715                 if (!ptr)
 716                         break;
 717
 718                 if (veth_is_xdp_frame(ptr)) {
 719                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 720
 721                         bytes += frame->len;
 722                         skb = veth_xdp_rcv_one(rq, frame, &xdp_xmit_one, bq);
 723                 } else {
 724                         skb = ptr;
 725                         bytes += skb->len;
 726                         skb = veth_xdp_rcv_skb(rq, skb, &xdp_xmit_one, bq);
 727                 }
 728                 *xdp_xmit |= xdp_xmit_one;
 729
 730                 if (skb)
 731                         napi_gro_receive(&rq->xdp_napi, skb);
 732                 else if (!xdp_xmit_one)
 733                         drops++;
 734
 735                 done++;
 736         }
 737
 738         u64_stats_update_begin(&rq->stats.syncp);
 739         rq->stats.xdp_packets += done;
 740         rq->stats.xdp_bytes += bytes;
 741         rq->stats.xdp_drops += drops;
 742         u64_stats_update_end(&rq->stats.syncp);
 743
 744         return done;
 745 }
 746
 747 static int veth_poll(struct napi_struct *napi, int budget)
 748 {
 749         struct veth_rq *rq =
 750                 container_of(napi, struct veth_rq, xdp_napi);
 751         unsigned int xdp_xmit = 0;
 752         struct veth_xdp_tx_bq bq;
 753         int done;
 754
 755         bq.count = 0;
 756
 757         xdp_set_return_frame_no_direct();
 758         done = veth_xdp_rcv(rq, budget, &xdp_xmit, &bq);
 759
 760         if (done < budget && napi_complete_done(napi, done)) {
 761                 /* Write rx_notify_masked before reading ptr_ring */
 762                 smp_store_mb(rq->rx_notify_masked, false);
 763                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 764                         rq->rx_notify_masked = true;
 765                         napi_schedule(&rq->xdp_napi);
 766                 }
 767         }
 768
 769         if (xdp_xmit & VETH_XDP_TX)
 770                 veth_xdp_flush(rq->dev, &bq);
 771         if (xdp_xmit & VETH_XDP_REDIR)
 772                 xdp_do_flush_map();
 773         xdp_clear_return_frame_no_direct();
 774
 775         return done;
 776 }
 777
 778 static int veth_napi_add(struct net_device *dev)
 779 {
 780         struct veth_priv *priv = netdev_priv(dev);
 781         int err, i;
 782
 783         for (i = 0; i < dev->real_num_rx_queues; i++) {
 784                 struct veth_rq *rq = &priv->rq[i];
 785
 786                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 787                 if (err)
 788                         goto err_xdp_ring;
 789         }
 790
 791         for (i = 0; i < dev->real_num_rx_queues; i++) {
 792                 struct veth_rq *rq = &priv->rq[i];
 793
 794                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 795                 napi_enable(&rq->xdp_napi);
 796         }
 797
 798         return 0;
 799 err_xdp_ring:
 800         for (i--; i >= 0; i--)
 801                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 802
 803         return err;
 804 }
 805
 806 static void veth_napi_del(struct net_device *dev)
 807 {
 808         struct veth_priv *priv = netdev_priv(dev);
 809         int i;
 810
 811         for (i = 0; i < dev->real_num_rx_queues; i++) {
 812                 struct veth_rq *rq = &priv->rq[i];
 813
 814                 napi_disable(&rq->xdp_napi);
 815                 napi_hash_del(&rq->xdp_napi);
 816         }
 817         synchronize_net();
 818
 819         for (i = 0; i < dev->real_num_rx_queues; i++) {
 820                 struct veth_rq *rq = &priv->rq[i];
 821
 822                 netif_napi_del(&rq->xdp_napi);
 823                 rq->rx_notify_masked = false;
 824                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 825         }
 826 }
 827
 828 static int veth_enable_xdp(struct net_device *dev)
 829 {
 830         struct veth_priv *priv = netdev_priv(dev);
 831         int err, i;
 832
 833         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 834                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 835                         struct veth_rq *rq = &priv->rq[i];
 836
 837                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i);
 838                         if (err < 0)
 839                                 goto err_rxq_reg;
 840
 841                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 842                                                          MEM_TYPE_PAGE_SHARED,
 843                                                          NULL);
 844                         if (err < 0)
 845                                 goto err_reg_mem;
 846
 847                         /* Save original mem info as it can be overwritten */
 848                         rq->xdp_mem = rq->xdp_rxq.mem;
 849                 }
 850
 851                 err = veth_napi_add(dev);
 852                 if (err)
 853                         goto err_rxq_reg;
 854         }
 855
 856         for (i = 0; i < dev->real_num_rx_queues; i++)
 857                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 858
 859         return 0;
 860 err_reg_mem:
 861         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 862 err_rxq_reg:
 863         for (i--; i >= 0; i--)
 864                 xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 865
 866         return err;
 867 }
 868
 869 static void veth_disable_xdp(struct net_device *dev)
 870 {
 871         struct veth_priv *priv = netdev_priv(dev);
 872         int i;
 873
 874         for (i = 0; i < dev->real_num_rx_queues; i++)
 875                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 876         veth_napi_del(dev);
 877         for (i = 0; i < dev->real_num_rx_queues; i++) {
 878                 struct veth_rq *rq = &priv->rq[i];
 879
 880                 rq->xdp_rxq.mem = rq->xdp_mem;
 881                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 882         }
 883 }
 884
 885 static int veth_open(struct net_device *dev)
 886 {
 887         struct veth_priv *priv = netdev_priv(dev);
 888         struct net_device *peer = rtnl_dereference(priv->peer);
 889         int err;
 890
 891         if (!peer)
 892                 return -ENOTCONN;
 893
 894         if (priv->_xdp_prog) {
 895                 err = veth_enable_xdp(dev);
 896                 if (err)
 897                         return err;
 898         }
 899
 900         if (peer->flags & IFF_UP) {
 901                 netif_carrier_on(dev);
 902                 netif_carrier_on(peer);
 903         }
 904
 905         return 0;
 906 }
 907
 908 static int veth_close(struct net_device *dev)
 909 {
 910         struct veth_priv *priv = netdev_priv(dev);
 911         struct net_device *peer = rtnl_dereference(priv->peer);
 912
 913         netif_carrier_off(dev);
 914         if (peer)
 915                 netif_carrier_off(peer);
 916
 917         if (priv->_xdp_prog)
 918                 veth_disable_xdp(dev);
 919
 920         return 0;
 921 }
 922
 923 static int is_valid_veth_mtu(int mtu)
 924 {
 925         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
 926 }
 927
 928 static int veth_alloc_queues(struct net_device *dev)
 929 {
 930         struct veth_priv *priv = netdev_priv(dev);
 931         int i;
 932
 933         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
 934         if (!priv->rq)
 935                 return -ENOMEM;
 936
 937         for (i = 0; i < dev->num_rx_queues; i++) {
 938                 priv->rq[i].dev = dev;
 939                 u64_stats_init(&priv->rq[i].stats.syncp);
 940         }
 941
 942         return 0;
 943 }
 944
 945 static void veth_free_queues(struct net_device *dev)
 946 {
 947         struct veth_priv *priv = netdev_priv(dev);
 948
 949         kfree(priv->rq);
 950 }
 951
 952 static int veth_dev_init(struct net_device *dev)
 953 {
 954         int err;
 955
 956         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
 957         if (!dev->lstats)
 958                 return -ENOMEM;
 959
 960         err = veth_alloc_queues(dev);
 961         if (err) {
 962                 free_percpu(dev->lstats);
 963                 return err;
 964         }
 965
 966         return 0;
 967 }
 968
 969 static void veth_dev_free(struct net_device *dev)
 970 {
 971         veth_free_queues(dev);
 972         free_percpu(dev->lstats);
 973 }
 974
 975 #ifdef CONFIG_NET_POLL_CONTROLLER
 976 static void veth_poll_controller(struct net_device *dev)
 977 {
 978         /* veth only receives frames when its peer sends one
 979          * Since it has nothing to do with disabling irqs, we are guaranteed
 980          * never to have pending data when we poll for it so
 981          * there is nothing to do here.
 982          *
 983          * We need this though so netpoll recognizes us as an interface that
 984          * supports polling, which enables bridge devices in virt setups to
 985          * still use netconsole
 986          */
 987 }
 988 #endif  /* CONFIG_NET_POLL_CONTROLLER */
 989
 990 static int veth_get_iflink(const struct net_device *dev)
 991 {
 992         struct veth_priv *priv = netdev_priv(dev);
 993         struct net_device *peer;
 994         int iflink;
 995
 996         rcu_read_lock();
 997         peer = rcu_dereference(priv->peer);
 998         iflink = peer ? peer->ifindex : 0;
 999         rcu_read_unlock();
1000
1001         return iflink;
1002 }
1003
1004 static netdev_features_t veth_fix_features(struct net_device *dev,
1005                                            netdev_features_t features)
1006 {
1007         struct veth_priv *priv = netdev_priv(dev);
1008         struct net_device *peer;
1009
1010         peer = rtnl_dereference(priv->peer);
1011         if (peer) {
1012                 struct veth_priv *peer_priv = netdev_priv(peer);
1013
1014                 if (peer_priv->_xdp_prog)
1015                         features &= ~NETIF_F_GSO_SOFTWARE;
1016         }
1017
1018         return features;
1019 }
1020
1021 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1022 {
1023         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1024         struct net_device *peer;
1025
1026         if (new_hr < 0)
1027                 new_hr = 0;
1028
1029         rcu_read_lock();
1030         peer = rcu_dereference(priv->peer);
1031         if (unlikely(!peer))
1032                 goto out;
1033
1034         peer_priv = netdev_priv(peer);
1035         priv->requested_headroom = new_hr;
1036         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1037         dev->needed_headroom = new_hr;
1038         peer->needed_headroom = new_hr;
1039
1040 out:
1041         rcu_read_unlock();
1042 }
1043
1044 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1045                         struct netlink_ext_ack *extack)
1046 {
1047         struct veth_priv *priv = netdev_priv(dev);
1048         struct bpf_prog *old_prog;
1049         struct net_device *peer;
1050         unsigned int max_mtu;
1051         int err;
1052
1053         old_prog = priv->_xdp_prog;
1054         priv->_xdp_prog = prog;
1055         peer = rtnl_dereference(priv->peer);
1056
1057         if (prog) {
1058                 if (!peer) {
1059                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1060                         err = -ENOTCONN;
1061                         goto err;
1062                 }
1063
1064                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
1065                           peer->hard_header_len -
1066                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1067                 if (peer->mtu > max_mtu) {
1068                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1069                         err = -ERANGE;
1070                         goto err;
1071                 }
1072
1073                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1074                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1075                         err = -ENOSPC;
1076                         goto err;
1077                 }
1078
1079                 if (dev->flags & IFF_UP) {
1080                         err = veth_enable_xdp(dev);
1081                         if (err) {
1082                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1083                                 goto err;
1084                         }
1085                 }
1086
1087                 if (!old_prog) {
1088                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1089                         peer->max_mtu = max_mtu;
1090                 }
1091         }
1092
1093         if (old_prog) {
1094                 if (!prog) {
1095                         if (dev->flags & IFF_UP)
1096                                 veth_disable_xdp(dev);
1097
1098                         if (peer) {
1099                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1100                                 peer->max_mtu = ETH_MAX_MTU;
1101                         }
1102                 }
1103                 bpf_prog_put(old_prog);
1104         }
1105
1106         if ((!!old_prog ^ !!prog) && peer)
1107                 netdev_update_features(peer);
1108
1109         return 0;
1110 err:
1111         priv->_xdp_prog = old_prog;
1112
1113         return err;
1114 }
1115
1116 static u32 veth_xdp_query(struct net_device *dev)
1117 {
1118         struct veth_priv *priv = netdev_priv(dev);
1119         const struct bpf_prog *xdp_prog;
1120
1121         xdp_prog = priv->_xdp_prog;
1122         if (xdp_prog)
1123                 return xdp_prog->aux->id;
1124
1125         return 0;
1126 }
1127
1128 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1129 {
1130         switch (xdp->command) {
1131         case XDP_SETUP_PROG:
1132                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1133         case XDP_QUERY_PROG:
1134                 xdp->prog_id = veth_xdp_query(dev);
1135                 return 0;
1136         default:
1137                 return -EINVAL;
1138         }
1139 }
1140
1141 static const struct net_device_ops veth_netdev_ops = {
1142         .ndo_init            = veth_dev_init,
1143         .ndo_open            = veth_open,
1144         .ndo_stop            = veth_close,
1145         .ndo_start_xmit      = veth_xmit,
1146         .ndo_get_stats64     = veth_get_stats64,
1147         .ndo_set_rx_mode     = veth_set_multicast_list,
1148         .ndo_set_mac_address = eth_mac_addr,
1149 #ifdef CONFIG_NET_POLL_CONTROLLER
1150         .ndo_poll_controller    = veth_poll_controller,
1151 #endif
1152         .ndo_get_iflink         = veth_get_iflink,
1153         .ndo_fix_features       = veth_fix_features,
1154         .ndo_features_check     = passthru_features_check,
1155         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1156         .ndo_bpf                = veth_xdp,
1157         .ndo_xdp_xmit           = veth_xdp_xmit,
1158 };
1159
1160 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1161                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1162                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1163                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1164                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1165
1166 static void veth_setup(struct net_device *dev)
1167 {
1168         ether_setup(dev);
1169
1170         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1171         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1172         dev->priv_flags |= IFF_NO_QUEUE;
1173         dev->priv_flags |= IFF_PHONY_HEADROOM;
1174
1175         dev->netdev_ops = &veth_netdev_ops;
1176         dev->ethtool_ops = &veth_ethtool_ops;
1177         dev->features |= NETIF_F_LLTX;
1178         dev->features |= VETH_FEATURES;
1179         dev->vlan_features = dev->features &
1180                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1181                                NETIF_F_HW_VLAN_STAG_TX |
1182                                NETIF_F_HW_VLAN_CTAG_RX |
1183                                NETIF_F_HW_VLAN_STAG_RX);
1184         dev->needs_free_netdev = true;
1185         dev->priv_destructor = veth_dev_free;
1186         dev->max_mtu = ETH_MAX_MTU;
1187
1188         dev->hw_features = VETH_FEATURES;
1189         dev->hw_enc_features = VETH_FEATURES;
1190         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1191 }
1192
1193 /*
1194  * netlink interface
1195  */
1196
1197 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1198                          struct netlink_ext_ack *extack)
1199 {
1200         if (tb[IFLA_ADDRESS]) {
1201                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1202                         return -EINVAL;
1203                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1204                         return -EADDRNOTAVAIL;
1205         }
1206         if (tb[IFLA_MTU]) {
1207                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1208                         return -EINVAL;
1209         }
1210         return 0;
1211 }
1212
1213 static struct rtnl_link_ops veth_link_ops;
1214
1215 static int veth_newlink(struct net *src_net, struct net_device *dev,
1216                         struct nlattr *tb[], struct nlattr *data[],
1217                         struct netlink_ext_ack *extack)
1218 {
1219         int err;
1220         struct net_device *peer;
1221         struct veth_priv *priv;
1222         char ifname[IFNAMSIZ];
1223         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1224         unsigned char name_assign_type;
1225         struct ifinfomsg *ifmp;
1226         struct net *net;
1227
1228         /*
1229          * create and register peer first
1230          */
1231         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1232                 struct nlattr *nla_peer;
1233
1234                 nla_peer = data[VETH_INFO_PEER];
1235                 ifmp = nla_data(nla_peer);
1236                 err = rtnl_nla_parse_ifla(peer_tb,
1237                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1238                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1239                                           NULL);
1240                 if (err < 0)
1241                         return err;
1242
1243                 err = veth_validate(peer_tb, NULL, extack);
1244                 if (err < 0)
1245                         return err;
1246
1247                 tbp = peer_tb;
1248         } else {
1249                 ifmp = NULL;
1250                 tbp = tb;
1251         }
1252
1253         if (ifmp && tbp[IFLA_IFNAME]) {
1254                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1255                 name_assign_type = NET_NAME_USER;
1256         } else {
1257                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1258                 name_assign_type = NET_NAME_ENUM;
1259         }
1260
1261         net = rtnl_link_get_net(src_net, tbp);
1262         if (IS_ERR(net))
1263                 return PTR_ERR(net);
1264
1265         peer = rtnl_create_link(net, ifname, name_assign_type,
1266                                 &veth_link_ops, tbp, extack);
1267         if (IS_ERR(peer)) {
1268                 put_net(net);
1269                 return PTR_ERR(peer);
1270         }
1271
1272         if (!ifmp || !tbp[IFLA_ADDRESS])
1273                 eth_hw_addr_random(peer);
1274
1275         if (ifmp && (dev->ifindex != 0))
1276                 peer->ifindex = ifmp->ifi_index;
1277
1278         peer->gso_max_size = dev->gso_max_size;
1279         peer->gso_max_segs = dev->gso_max_segs;
1280
1281         err = register_netdevice(peer);
1282         put_net(net);
1283         net = NULL;
1284         if (err < 0)
1285                 goto err_register_peer;
1286
1287         netif_carrier_off(peer);
1288
1289         err = rtnl_configure_link(peer, ifmp);
1290         if (err < 0)
1291                 goto err_configure_peer;
1292
1293         /*
1294          * register dev last
1295          *
1296          * note, that since we've registered new device the dev's name
1297          * should be re-allocated
1298          */
1299
1300         if (tb[IFLA_ADDRESS] == NULL)
1301                 eth_hw_addr_random(dev);
1302
1303         if (tb[IFLA_IFNAME])
1304                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1305         else
1306                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1307
1308         err = register_netdevice(dev);
1309         if (err < 0)
1310                 goto err_register_dev;
1311
1312         netif_carrier_off(dev);
1313
1314         /*
1315          * tie the deviced together
1316          */
1317
1318         priv = netdev_priv(dev);
1319         rcu_assign_pointer(priv->peer, peer);
1320
1321         priv = netdev_priv(peer);
1322         rcu_assign_pointer(priv->peer, dev);
1323
1324         return 0;
1325
1326 err_register_dev:
1327         /* nothing to do */
1328 err_configure_peer:
1329         unregister_netdevice(peer);
1330         return err;
1331
1332 err_register_peer:
1333         free_netdev(peer);
1334         return err;
1335 }
1336
1337 static void veth_dellink(struct net_device *dev, struct list_head *head)
1338 {
1339         struct veth_priv *priv;
1340         struct net_device *peer;
1341
1342         priv = netdev_priv(dev);
1343         peer = rtnl_dereference(priv->peer);
1344
1345         /* Note : dellink() is called from default_device_exit_batch(),
1346          * before a rcu_synchronize() point. The devices are guaranteed
1347          * not being freed before one RCU grace period.
1348          */
1349         RCU_INIT_POINTER(priv->peer, NULL);
1350         unregister_netdevice_queue(dev, head);
1351
1352         if (peer) {
1353                 priv = netdev_priv(peer);
1354                 RCU_INIT_POINTER(priv->peer, NULL);
1355                 unregister_netdevice_queue(peer, head);
1356         }
1357 }
1358
1359 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1360         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1361 };
1362
1363 static struct net *veth_get_link_net(const struct net_device *dev)
1364 {
1365         struct veth_priv *priv = netdev_priv(dev);
1366         struct net_device *peer = rtnl_dereference(priv->peer);
1367
1368         return peer ? dev_net(peer) : dev_net(dev);
1369 }
1370
1371 static struct rtnl_link_ops veth_link_ops = {
1372         .kind           = DRV_NAME,
1373         .priv_size      = sizeof(struct veth_priv),
1374         .setup          = veth_setup,
1375         .validate       = veth_validate,
1376         .newlink        = veth_newlink,
1377         .dellink        = veth_dellink,
1378         .policy         = veth_policy,
1379         .maxtype        = VETH_INFO_MAX,
1380         .get_link_net   = veth_get_link_net,
1381 };
1382
1383 /*
1384  * init/fini
1385  */
1386
1387 static __init int veth_init(void)
1388 {
1389         return rtnl_link_register(&veth_link_ops);
1390 }
1391
1392 static __exit void veth_exit(void)
1393 {
1394         rtnl_link_unregister(&veth_link_ops);
1395 }
1396
1397 module_init(veth_init);
1398 module_exit(veth_exit);
1399
1400 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1401 MODULE_LICENSE("GPL v2");
1402 MODULE_ALIAS_RTNL_LINK(DRV_NAME);