drivers/net/veth.c

   1 /*
   2  *  drivers/net/veth.c
   3  *
   4  *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
   5  *
   6  * Author: Pavel Emelianov <xemul@openvz.org>
   7  * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
   8  *
   9  */
  10
  11 #include <linux/netdevice.h>
  12 #include <linux/slab.h>
  13 #include <linux/ethtool.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/u64_stats_sync.h>
  16
  17 #include <net/rtnetlink.h>
  18 #include <net/dst.h>
  19 #include <net/xfrm.h>
  20 #include <net/xdp.h>
  21 #include <linux/veth.h>
  22 #include <linux/module.h>
  23 #include <linux/bpf.h>
  24 #include <linux/filter.h>
  25 #include <linux/ptr_ring.h>
  26 #include <linux/bpf_trace.h>
  27 #include <linux/net_tstamp.h>
  28
  29 #define DRV_NAME        "veth"
  30 #define DRV_VERSION     "1.0"
  31
  32 #define VETH_XDP_FLAG           BIT(0)
  33 #define VETH_RING_SIZE          256
  34 #define VETH_XDP_HEADROOM       (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
  35
  36 /* Separating two types of XDP xmit */
  37 #define VETH_XDP_TX             BIT(0)
  38 #define VETH_XDP_REDIR          BIT(1)
  39
  40 struct veth_rq_stats {
  41         u64                     xdp_packets;
  42         u64                     xdp_bytes;
  43         u64                     xdp_drops;
  44         struct u64_stats_sync   syncp;
  45 };
  46
  47 struct veth_rq {
  48         struct napi_struct      xdp_napi;
  49         struct net_device       *dev;
  50         struct bpf_prog __rcu   *xdp_prog;
  51         struct xdp_mem_info     xdp_mem;
  52         struct veth_rq_stats    stats;
  53         bool                    rx_notify_masked;
  54         struct ptr_ring         xdp_ring;
  55         struct xdp_rxq_info     xdp_rxq;
  56 };
  57
  58 struct veth_priv {
  59         struct net_device __rcu *peer;
  60         atomic64_t              dropped;
  61         struct bpf_prog         *_xdp_prog;
  62         struct veth_rq          *rq;
  63         unsigned int            requested_headroom;
  64 };
  65
  66 /*
  67  * ethtool interface
  68  */
  69
  70 struct veth_q_stat_desc {
  71         char    desc[ETH_GSTRING_LEN];
  72         size_t  offset;
  73 };
  74
  75 #define VETH_RQ_STAT(m) offsetof(struct veth_rq_stats, m)
  76
  77 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  78         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  79         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  80         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
  81 };
  82
  83 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
  84
  85 static struct {
  86         const char string[ETH_GSTRING_LEN];
  87 } ethtool_stats_keys[] = {
  88         { "peer_ifindex" },
  89 };
  90
  91 static int veth_get_link_ksettings(struct net_device *dev,
  92                                    struct ethtool_link_ksettings *cmd)
  93 {
  94         cmd->base.speed         = SPEED_10000;
  95         cmd->base.duplex        = DUPLEX_FULL;
  96         cmd->base.port          = PORT_TP;
  97         cmd->base.autoneg       = AUTONEG_DISABLE;
  98         return 0;
  99 }
 100
 101 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 102 {
 103         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 104         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 105 }
 106
 107 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 108 {
 109         char *p = (char *)buf;
 110         int i, j;
 111
 112         switch(stringset) {
 113         case ETH_SS_STATS:
 114                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 115                 p += sizeof(ethtool_stats_keys);
 116                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 117                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 118                                 snprintf(p, ETH_GSTRING_LEN,
 119                                          "rx_queue_%u_%.11s",
 120                                          i, veth_rq_stats_desc[j].desc);
 121                                 p += ETH_GSTRING_LEN;
 122                         }
 123                 }
 124                 break;
 125         }
 126 }
 127
 128 static int veth_get_sset_count(struct net_device *dev, int sset)
 129 {
 130         switch (sset) {
 131         case ETH_SS_STATS:
 132                 return ARRAY_SIZE(ethtool_stats_keys) +
 133                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues;
 134         default:
 135                 return -EOPNOTSUPP;
 136         }
 137 }
 138
 139 static void veth_get_ethtool_stats(struct net_device *dev,
 140                 struct ethtool_stats *stats, u64 *data)
 141 {
 142         struct veth_priv *priv = netdev_priv(dev);
 143         struct net_device *peer = rtnl_dereference(priv->peer);
 144         int i, j, idx;
 145
 146         data[0] = peer ? peer->ifindex : 0;
 147         idx = 1;
 148         for (i = 0; i < dev->real_num_rx_queues; i++) {
 149                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 150                 const void *stats_base = (void *)rq_stats;
 151                 unsigned int start;
 152                 size_t offset;
 153
 154                 do {
 155                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 156                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 157                                 offset = veth_rq_stats_desc[j].offset;
 158                                 data[idx + j] = *(u64 *)(stats_base + offset);
 159                         }
 160                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 161                 idx += VETH_RQ_STATS_LEN;
 162         }
 163 }
 164
 165 static int veth_get_ts_info(struct net_device *dev,
 166                             struct ethtool_ts_info *info)
 167 {
 168         info->so_timestamping =
 169                 SOF_TIMESTAMPING_TX_SOFTWARE |
 170                 SOF_TIMESTAMPING_RX_SOFTWARE |
 171                 SOF_TIMESTAMPING_SOFTWARE;
 172         info->phc_index = -1;
 173
 174         return 0;
 175 }
 176
 177 static const struct ethtool_ops veth_ethtool_ops = {
 178         .get_drvinfo            = veth_get_drvinfo,
 179         .get_link               = ethtool_op_get_link,
 180         .get_strings            = veth_get_strings,
 181         .get_sset_count         = veth_get_sset_count,
 182         .get_ethtool_stats      = veth_get_ethtool_stats,
 183         .get_link_ksettings     = veth_get_link_ksettings,
 184         .get_ts_info            = veth_get_ts_info,
 185 };
 186
 187 /* general routines */
 188
 189 static bool veth_is_xdp_frame(void *ptr)
 190 {
 191         return (unsigned long)ptr & VETH_XDP_FLAG;
 192 }
 193
 194 static void *veth_ptr_to_xdp(void *ptr)
 195 {
 196         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 197 }
 198
 199 static void *veth_xdp_to_ptr(void *ptr)
 200 {
 201         return (void *)((unsigned long)ptr | VETH_XDP_FLAG);
 202 }
 203
 204 static void veth_ptr_free(void *ptr)
 205 {
 206         if (veth_is_xdp_frame(ptr))
 207                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 208         else
 209                 kfree_skb(ptr);
 210 }
 211
 212 static void __veth_xdp_flush(struct veth_rq *rq)
 213 {
 214         /* Write ptr_ring before reading rx_notify_masked */
 215         smp_mb();
 216         if (!rq->rx_notify_masked) {
 217                 rq->rx_notify_masked = true;
 218                 napi_schedule(&rq->xdp_napi);
 219         }
 220 }
 221
 222 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 223 {
 224         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 225                 dev_kfree_skb_any(skb);
 226                 return NET_RX_DROP;
 227         }
 228
 229         return NET_RX_SUCCESS;
 230 }
 231
 232 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 233                             struct veth_rq *rq, bool xdp)
 234 {
 235         return __dev_forward_skb(dev, skb) ?: xdp ?
 236                 veth_xdp_rx(rq, skb) :
 237                 netif_rx(skb);
 238 }
 239
 240 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 241 {
 242         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 243         struct veth_rq *rq = NULL;
 244         struct net_device *rcv;
 245         int length = skb->len;
 246         bool rcv_xdp = false;
 247         int rxq;
 248
 249         rcu_read_lock();
 250         rcv = rcu_dereference(priv->peer);
 251         if (unlikely(!rcv)) {
 252                 kfree_skb(skb);
 253                 goto drop;
 254         }
 255
 256         rcv_priv = netdev_priv(rcv);
 257         rxq = skb_get_queue_mapping(skb);
 258         if (rxq < rcv->real_num_rx_queues) {
 259                 rq = &rcv_priv->rq[rxq];
 260                 rcv_xdp = rcu_access_pointer(rq->xdp_prog);
 261                 if (rcv_xdp)
 262                         skb_record_rx_queue(skb, rxq);
 263         }
 264
 265         skb_tx_timestamp(skb);
 266         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 267                 if (!rcv_xdp) {
 268                         struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
 269
 270                         u64_stats_update_begin(&stats->syncp);
 271                         stats->bytes += length;
 272                         stats->packets++;
 273                         u64_stats_update_end(&stats->syncp);
 274                 }
 275         } else {
 276 drop:
 277                 atomic64_inc(&priv->dropped);
 278         }
 279
 280         if (rcv_xdp)
 281                 __veth_xdp_flush(rq);
 282
 283         rcu_read_unlock();
 284
 285         return NETDEV_TX_OK;
 286 }
 287
 288 static u64 veth_stats_tx(struct pcpu_lstats *result, struct net_device *dev)
 289 {
 290         struct veth_priv *priv = netdev_priv(dev);
 291         int cpu;
 292
 293         result->packets = 0;
 294         result->bytes = 0;
 295         for_each_possible_cpu(cpu) {
 296                 struct pcpu_lstats *stats = per_cpu_ptr(dev->lstats, cpu);
 297                 u64 packets, bytes;
 298                 unsigned int start;
 299
 300                 do {
 301                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 302                         packets = stats->packets;
 303                         bytes = stats->bytes;
 304                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 305                 result->packets += packets;
 306                 result->bytes += bytes;
 307         }
 308         return atomic64_read(&priv->dropped);
 309 }
 310
 311 static void veth_stats_rx(struct veth_rq_stats *result, struct net_device *dev)
 312 {
 313         struct veth_priv *priv = netdev_priv(dev);
 314         int i;
 315
 316         result->xdp_packets = 0;
 317         result->xdp_bytes = 0;
 318         result->xdp_drops = 0;
 319         for (i = 0; i < dev->num_rx_queues; i++) {
 320                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 321                 u64 packets, bytes, drops;
 322                 unsigned int start;
 323
 324                 do {
 325                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 326                         packets = stats->xdp_packets;
 327                         bytes = stats->xdp_bytes;
 328                         drops = stats->xdp_drops;
 329                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 330                 result->xdp_packets += packets;
 331                 result->xdp_bytes += bytes;
 332                 result->xdp_drops += drops;
 333         }
 334 }
 335
 336 static void veth_get_stats64(struct net_device *dev,
 337                              struct rtnl_link_stats64 *tot)
 338 {
 339         struct veth_priv *priv = netdev_priv(dev);
 340         struct net_device *peer;
 341         struct veth_rq_stats rx;
 342         struct pcpu_lstats tx;
 343
 344         tot->tx_dropped = veth_stats_tx(&tx, dev);
 345         tot->tx_bytes = tx.bytes;
 346         tot->tx_packets = tx.packets;
 347
 348         veth_stats_rx(&rx, dev);
 349         tot->rx_dropped = rx.xdp_drops;
 350         tot->rx_bytes = rx.xdp_bytes;
 351         tot->rx_packets = rx.xdp_packets;
 352
 353         rcu_read_lock();
 354         peer = rcu_dereference(priv->peer);
 355         if (peer) {
 356                 tot->rx_dropped += veth_stats_tx(&tx, peer);
 357                 tot->rx_bytes += tx.bytes;
 358                 tot->rx_packets += tx.packets;
 359
 360                 veth_stats_rx(&rx, peer);
 361                 tot->tx_bytes += rx.xdp_bytes;
 362                 tot->tx_packets += rx.xdp_packets;
 363         }
 364         rcu_read_unlock();
 365 }
 366
 367 /* fake multicast ability */
 368 static void veth_set_multicast_list(struct net_device *dev)
 369 {
 370 }
 371
 372 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 373                                       int buflen)
 374 {
 375         struct sk_buff *skb;
 376
 377         if (!buflen) {
 378                 buflen = SKB_DATA_ALIGN(headroom + len) +
 379                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 380         }
 381         skb = build_skb(head, buflen);
 382         if (!skb)
 383                 return NULL;
 384
 385         skb_reserve(skb, headroom);
 386         skb_put(skb, len);
 387
 388         return skb;
 389 }
 390
 391 static int veth_select_rxq(struct net_device *dev)
 392 {
 393         return smp_processor_id() % dev->real_num_rx_queues;
 394 }
 395
 396 static int veth_xdp_xmit(struct net_device *dev, int n,
 397                          struct xdp_frame **frames, u32 flags)
 398 {
 399         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 400         struct net_device *rcv;
 401         int i, ret, drops = n;
 402         unsigned int max_len;
 403         struct veth_rq *rq;
 404
 405         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) {
 406                 ret = -EINVAL;
 407                 goto drop;
 408         }
 409
 410         rcv = rcu_dereference(priv->peer);
 411         if (unlikely(!rcv)) {
 412                 ret = -ENXIO;
 413                 goto drop;
 414         }
 415
 416         rcv_priv = netdev_priv(rcv);
 417         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 418         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 419          * side. This means an XDP program is loaded on the peer and the peer
 420          * device is up.
 421          */
 422         if (!rcu_access_pointer(rq->xdp_prog)) {
 423                 ret = -ENXIO;
 424                 goto drop;
 425         }
 426
 427         drops = 0;
 428         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 429
 430         spin_lock(&rq->xdp_ring.producer_lock);
 431         for (i = 0; i < n; i++) {
 432                 struct xdp_frame *frame = frames[i];
 433                 void *ptr = veth_xdp_to_ptr(frame);
 434
 435                 if (unlikely(frame->len > max_len ||
 436                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 437                         xdp_return_frame_rx_napi(frame);
 438                         drops++;
 439                 }
 440         }
 441         spin_unlock(&rq->xdp_ring.producer_lock);
 442
 443         if (flags & XDP_XMIT_FLUSH)
 444                 __veth_xdp_flush(rq);
 445
 446         if (likely(!drops))
 447                 return n;
 448
 449         ret = n - drops;
 450 drop:
 451         atomic64_add(drops, &priv->dropped);
 452
 453         return ret;
 454 }
 455
 456 static void veth_xdp_flush(struct net_device *dev)
 457 {
 458         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 459         struct net_device *rcv;
 460         struct veth_rq *rq;
 461
 462         rcu_read_lock();
 463         rcv = rcu_dereference(priv->peer);
 464         if (unlikely(!rcv))
 465                 goto out;
 466
 467         rcv_priv = netdev_priv(rcv);
 468         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 469         /* xdp_ring is initialized on receive side? */
 470         if (unlikely(!rcu_access_pointer(rq->xdp_prog)))
 471                 goto out;
 472
 473         __veth_xdp_flush(rq);
 474 out:
 475         rcu_read_unlock();
 476 }
 477
 478 static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
 479 {
 480         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
 481
 482         if (unlikely(!frame))
 483                 return -EOVERFLOW;
 484
 485         return veth_xdp_xmit(dev, 1, &frame, 0);
 486 }
 487
 488 static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 489                                         struct xdp_frame *frame,
 490                                         unsigned int *xdp_xmit)
 491 {
 492         void *hard_start = frame->data - frame->headroom;
 493         void *head = hard_start - sizeof(struct xdp_frame);
 494         int len = frame->len, delta = 0;
 495         struct xdp_frame orig_frame;
 496         struct bpf_prog *xdp_prog;
 497         unsigned int headroom;
 498         struct sk_buff *skb;
 499
 500         rcu_read_lock();
 501         xdp_prog = rcu_dereference(rq->xdp_prog);
 502         if (likely(xdp_prog)) {
 503                 struct xdp_buff xdp;
 504                 u32 act;
 505
 506                 xdp.data_hard_start = hard_start;
 507                 xdp.data = frame->data;
 508                 xdp.data_end = frame->data + frame->len;
 509                 xdp.data_meta = frame->data - frame->metasize;
 510                 xdp.rxq = &rq->xdp_rxq;
 511
 512                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 513
 514                 switch (act) {
 515                 case XDP_PASS:
 516                         delta = frame->data - xdp.data;
 517                         len = xdp.data_end - xdp.data;
 518                         break;
 519                 case XDP_TX:
 520                         orig_frame = *frame;
 521                         xdp.data_hard_start = head;
 522                         xdp.rxq->mem = frame->mem;
 523                         if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 524                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 525                                 frame = &orig_frame;
 526                                 goto err_xdp;
 527                         }
 528                         *xdp_xmit |= VETH_XDP_TX;
 529                         rcu_read_unlock();
 530                         goto xdp_xmit;
 531                 case XDP_REDIRECT:
 532                         orig_frame = *frame;
 533                         xdp.data_hard_start = head;
 534                         xdp.rxq->mem = frame->mem;
 535                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 536                                 frame = &orig_frame;
 537                                 goto err_xdp;
 538                         }
 539                         *xdp_xmit |= VETH_XDP_REDIR;
 540                         rcu_read_unlock();
 541                         goto xdp_xmit;
 542                 default:
 543                         bpf_warn_invalid_xdp_action(act);
 544                         /* fall through */
 545                 case XDP_ABORTED:
 546                         trace_xdp_exception(rq->dev, xdp_prog, act);
 547                         /* fall through */
 548                 case XDP_DROP:
 549                         goto err_xdp;
 550                 }
 551         }
 552         rcu_read_unlock();
 553
 554         headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
 555         skb = veth_build_skb(head, headroom, len, 0);
 556         if (!skb) {
 557                 xdp_return_frame(frame);
 558                 goto err;
 559         }
 560
 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 {
 575         u32 pktlen, headroom, act, metalen;
 576         void *orig_data, *orig_data_end;
 577         struct bpf_prog *xdp_prog;
 578         int mac_len, delta, off;
 579         struct xdp_buff xdp;
 580
 581         skb_orphan(skb);
 582
 583         rcu_read_lock();
 584         xdp_prog = rcu_dereference(rq->xdp_prog);
 585         if (unlikely(!xdp_prog)) {
 586                 rcu_read_unlock();
 587                 goto out;
 588         }
 589
 590         mac_len = skb->data - skb_mac_header(skb);
 591         pktlen = skb->len + mac_len;
 592         headroom = skb_headroom(skb) - mac_len;
 593
 594         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 595             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 596                 struct sk_buff *nskb;
 597                 int size, head_off;
 598                 void *head, *start;
 599                 struct page *page;
 600
 601                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 602                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 603                 if (size > PAGE_SIZE)
 604                         goto drop;
 605
 606                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 607                 if (!page)
 608                         goto drop;
 609
 610                 head = page_address(page);
 611                 start = head + VETH_XDP_HEADROOM;
 612                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 613                         page_frag_free(head);
 614                         goto drop;
 615                 }
 616
 617                 nskb = veth_build_skb(head,
 618                                       VETH_XDP_HEADROOM + mac_len, skb->len,
 619                                       PAGE_SIZE);
 620                 if (!nskb) {
 621                         page_frag_free(head);
 622                         goto drop;
 623                 }
 624
 625                 skb_copy_header(nskb, skb);
 626                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 627                 skb_headers_offset_update(nskb, head_off);
 628                 consume_skb(skb);
 629                 skb = nskb;
 630         }
 631
 632         xdp.data_hard_start = skb->head;
 633         xdp.data = skb_mac_header(skb);
 634         xdp.data_end = xdp.data + pktlen;
 635         xdp.data_meta = xdp.data;
 636         xdp.rxq = &rq->xdp_rxq;
 637         orig_data = xdp.data;
 638         orig_data_end = xdp.data_end;
 639
 640         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 641
 642         switch (act) {
 643         case XDP_PASS:
 644                 break;
 645         case XDP_TX:
 646                 get_page(virt_to_page(xdp.data));
 647                 consume_skb(skb);
 648                 xdp.rxq->mem = rq->xdp_mem;
 649                 if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 650                         trace_xdp_exception(rq->dev, xdp_prog, act);
 651                         goto err_xdp;
 652                 }
 653                 *xdp_xmit |= VETH_XDP_TX;
 654                 rcu_read_unlock();
 655                 goto xdp_xmit;
 656         case XDP_REDIRECT:
 657                 get_page(virt_to_page(xdp.data));
 658                 consume_skb(skb);
 659                 xdp.rxq->mem = rq->xdp_mem;
 660                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog))
 661                         goto err_xdp;
 662                 *xdp_xmit |= VETH_XDP_REDIR;
 663                 rcu_read_unlock();
 664                 goto xdp_xmit;
 665         default:
 666                 bpf_warn_invalid_xdp_action(act);
 667                 /* fall through */
 668         case XDP_ABORTED:
 669                 trace_xdp_exception(rq->dev, xdp_prog, act);
 670                 /* fall through */
 671         case XDP_DROP:
 672                 goto drop;
 673         }
 674         rcu_read_unlock();
 675
 676         delta = orig_data - xdp.data;
 677         off = mac_len + delta;
 678         if (off > 0)
 679                 __skb_push(skb, off);
 680         else if (off < 0)
 681                 __skb_pull(skb, -off);
 682         skb->mac_header -= delta;
 683         off = xdp.data_end - orig_data_end;
 684         if (off != 0)
 685                 __skb_put(skb, off);
 686         skb->protocol = eth_type_trans(skb, rq->dev);
 687
 688         metalen = xdp.data - xdp.data_meta;
 689         if (metalen)
 690                 skb_metadata_set(skb, metalen);
 691 out:
 692         return skb;
 693 drop:
 694         rcu_read_unlock();
 695         kfree_skb(skb);
 696         return NULL;
 697 err_xdp:
 698         rcu_read_unlock();
 699         page_frag_free(xdp.data);
 700 xdp_xmit:
 701         return NULL;
 702 }
 703
 704 static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit)
 705 {
 706         int i, done = 0, drops = 0, bytes = 0;
 707
 708         for (i = 0; i < budget; i++) {
 709                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 710                 unsigned int xdp_xmit_one = 0;
 711                 struct sk_buff *skb;
 712
 713                 if (!ptr)
 714                         break;
 715
 716                 if (veth_is_xdp_frame(ptr)) {
 717                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 718
 719                         bytes += frame->len;
 720                         skb = veth_xdp_rcv_one(rq, frame, &xdp_xmit_one);
 721                 } else {
 722                         skb = ptr;
 723                         bytes += skb->len;
 724                         skb = veth_xdp_rcv_skb(rq, skb, &xdp_xmit_one);
 725                 }
 726                 *xdp_xmit |= xdp_xmit_one;
 727
 728                 if (skb)
 729                         napi_gro_receive(&rq->xdp_napi, skb);
 730                 else if (!xdp_xmit_one)
 731                         drops++;
 732
 733                 done++;
 734         }
 735
 736         u64_stats_update_begin(&rq->stats.syncp);
 737         rq->stats.xdp_packets += done;
 738         rq->stats.xdp_bytes += bytes;
 739         rq->stats.xdp_drops += drops;
 740         u64_stats_update_end(&rq->stats.syncp);
 741
 742         return done;
 743 }
 744
 745 static int veth_poll(struct napi_struct *napi, int budget)
 746 {
 747         struct veth_rq *rq =
 748                 container_of(napi, struct veth_rq, xdp_napi);
 749         unsigned int xdp_xmit = 0;
 750         int done;
 751
 752         xdp_set_return_frame_no_direct();
 753         done = veth_xdp_rcv(rq, budget, &xdp_xmit);
 754
 755         if (done < budget && napi_complete_done(napi, done)) {
 756                 /* Write rx_notify_masked before reading ptr_ring */
 757                 smp_store_mb(rq->rx_notify_masked, false);
 758                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 759                         rq->rx_notify_masked = true;
 760                         napi_schedule(&rq->xdp_napi);
 761                 }
 762         }
 763
 764         if (xdp_xmit & VETH_XDP_TX)
 765                 veth_xdp_flush(rq->dev);
 766         if (xdp_xmit & VETH_XDP_REDIR)
 767                 xdp_do_flush_map();
 768         xdp_clear_return_frame_no_direct();
 769
 770         return done;
 771 }
 772
 773 static int veth_napi_add(struct net_device *dev)
 774 {
 775         struct veth_priv *priv = netdev_priv(dev);
 776         int err, i;
 777
 778         for (i = 0; i < dev->real_num_rx_queues; i++) {
 779                 struct veth_rq *rq = &priv->rq[i];
 780
 781                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 782                 if (err)
 783                         goto err_xdp_ring;
 784         }
 785
 786         for (i = 0; i < dev->real_num_rx_queues; i++) {
 787                 struct veth_rq *rq = &priv->rq[i];
 788
 789                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 790                 napi_enable(&rq->xdp_napi);
 791         }
 792
 793         return 0;
 794 err_xdp_ring:
 795         for (i--; i >= 0; i--)
 796                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 797
 798         return err;
 799 }
 800
 801 static void veth_napi_del(struct net_device *dev)
 802 {
 803         struct veth_priv *priv = netdev_priv(dev);
 804         int i;
 805
 806         for (i = 0; i < dev->real_num_rx_queues; i++) {
 807                 struct veth_rq *rq = &priv->rq[i];
 808
 809                 napi_disable(&rq->xdp_napi);
 810                 napi_hash_del(&rq->xdp_napi);
 811         }
 812         synchronize_net();
 813
 814         for (i = 0; i < dev->real_num_rx_queues; i++) {
 815                 struct veth_rq *rq = &priv->rq[i];
 816
 817                 netif_napi_del(&rq->xdp_napi);
 818                 rq->rx_notify_masked = false;
 819                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 820         }
 821 }
 822
 823 static int veth_enable_xdp(struct net_device *dev)
 824 {
 825         struct veth_priv *priv = netdev_priv(dev);
 826         int err, i;
 827
 828         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 829                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 830                         struct veth_rq *rq = &priv->rq[i];
 831
 832                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i);
 833                         if (err < 0)
 834                                 goto err_rxq_reg;
 835
 836                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 837                                                          MEM_TYPE_PAGE_SHARED,
 838                                                          NULL);
 839                         if (err < 0)
 840                                 goto err_reg_mem;
 841
 842                         /* Save original mem info as it can be overwritten */
 843                         rq->xdp_mem = rq->xdp_rxq.mem;
 844                 }
 845
 846                 err = veth_napi_add(dev);
 847                 if (err)
 848                         goto err_rxq_reg;
 849         }
 850
 851         for (i = 0; i < dev->real_num_rx_queues; i++)
 852                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 853
 854         return 0;
 855 err_reg_mem:
 856         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 857 err_rxq_reg:
 858         for (i--; i >= 0; i--)
 859                 xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 860
 861         return err;
 862 }
 863
 864 static void veth_disable_xdp(struct net_device *dev)
 865 {
 866         struct veth_priv *priv = netdev_priv(dev);
 867         int i;
 868
 869         for (i = 0; i < dev->real_num_rx_queues; i++)
 870                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 871         veth_napi_del(dev);
 872         for (i = 0; i < dev->real_num_rx_queues; i++) {
 873                 struct veth_rq *rq = &priv->rq[i];
 874
 875                 rq->xdp_rxq.mem = rq->xdp_mem;
 876                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 877         }
 878 }
 879
 880 static int veth_open(struct net_device *dev)
 881 {
 882         struct veth_priv *priv = netdev_priv(dev);
 883         struct net_device *peer = rtnl_dereference(priv->peer);
 884         int err;
 885
 886         if (!peer)
 887                 return -ENOTCONN;
 888
 889         if (priv->_xdp_prog) {
 890                 err = veth_enable_xdp(dev);
 891                 if (err)
 892                         return err;
 893         }
 894
 895         if (peer->flags & IFF_UP) {
 896                 netif_carrier_on(dev);
 897                 netif_carrier_on(peer);
 898         }
 899
 900         return 0;
 901 }
 902
 903 static int veth_close(struct net_device *dev)
 904 {
 905         struct veth_priv *priv = netdev_priv(dev);
 906         struct net_device *peer = rtnl_dereference(priv->peer);
 907
 908         netif_carrier_off(dev);
 909         if (peer)
 910                 netif_carrier_off(peer);
 911
 912         if (priv->_xdp_prog)
 913                 veth_disable_xdp(dev);
 914
 915         return 0;
 916 }
 917
 918 static int is_valid_veth_mtu(int mtu)
 919 {
 920         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
 921 }
 922
 923 static int veth_alloc_queues(struct net_device *dev)
 924 {
 925         struct veth_priv *priv = netdev_priv(dev);
 926         int i;
 927
 928         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
 929         if (!priv->rq)
 930                 return -ENOMEM;
 931
 932         for (i = 0; i < dev->num_rx_queues; i++) {
 933                 priv->rq[i].dev = dev;
 934                 u64_stats_init(&priv->rq[i].stats.syncp);
 935         }
 936
 937         return 0;
 938 }
 939
 940 static void veth_free_queues(struct net_device *dev)
 941 {
 942         struct veth_priv *priv = netdev_priv(dev);
 943
 944         kfree(priv->rq);
 945 }
 946
 947 static int veth_dev_init(struct net_device *dev)
 948 {
 949         int err;
 950
 951         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
 952         if (!dev->lstats)
 953                 return -ENOMEM;
 954
 955         err = veth_alloc_queues(dev);
 956         if (err) {
 957                 free_percpu(dev->lstats);
 958                 return err;
 959         }
 960
 961         return 0;
 962 }
 963
 964 static void veth_dev_free(struct net_device *dev)
 965 {
 966         veth_free_queues(dev);
 967         free_percpu(dev->lstats);
 968 }
 969
 970 #ifdef CONFIG_NET_POLL_CONTROLLER
 971 static void veth_poll_controller(struct net_device *dev)
 972 {
 973         /* veth only receives frames when its peer sends one
 974          * Since it has nothing to do with disabling irqs, we are guaranteed
 975          * never to have pending data when we poll for it so
 976          * there is nothing to do here.
 977          *
 978          * We need this though so netpoll recognizes us as an interface that
 979          * supports polling, which enables bridge devices in virt setups to
 980          * still use netconsole
 981          */
 982 }
 983 #endif  /* CONFIG_NET_POLL_CONTROLLER */
 984
 985 static int veth_get_iflink(const struct net_device *dev)
 986 {
 987         struct veth_priv *priv = netdev_priv(dev);
 988         struct net_device *peer;
 989         int iflink;
 990
 991         rcu_read_lock();
 992         peer = rcu_dereference(priv->peer);
 993         iflink = peer ? peer->ifindex : 0;
 994         rcu_read_unlock();
 995
 996         return iflink;
 997 }
 998
 999 static netdev_features_t veth_fix_features(struct net_device *dev,
1000                                            netdev_features_t features)
1001 {
1002         struct veth_priv *priv = netdev_priv(dev);
1003         struct net_device *peer;
1004
1005         peer = rtnl_dereference(priv->peer);
1006         if (peer) {
1007                 struct veth_priv *peer_priv = netdev_priv(peer);
1008
1009                 if (peer_priv->_xdp_prog)
1010                         features &= ~NETIF_F_GSO_SOFTWARE;
1011         }
1012
1013         return features;
1014 }
1015
1016 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1017 {
1018         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1019         struct net_device *peer;
1020
1021         if (new_hr < 0)
1022                 new_hr = 0;
1023
1024         rcu_read_lock();
1025         peer = rcu_dereference(priv->peer);
1026         if (unlikely(!peer))
1027                 goto out;
1028
1029         peer_priv = netdev_priv(peer);
1030         priv->requested_headroom = new_hr;
1031         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1032         dev->needed_headroom = new_hr;
1033         peer->needed_headroom = new_hr;
1034
1035 out:
1036         rcu_read_unlock();
1037 }
1038
1039 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1040                         struct netlink_ext_ack *extack)
1041 {
1042         struct veth_priv *priv = netdev_priv(dev);
1043         struct bpf_prog *old_prog;
1044         struct net_device *peer;
1045         unsigned int max_mtu;
1046         int err;
1047
1048         old_prog = priv->_xdp_prog;
1049         priv->_xdp_prog = prog;
1050         peer = rtnl_dereference(priv->peer);
1051
1052         if (prog) {
1053                 if (!peer) {
1054                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1055                         err = -ENOTCONN;
1056                         goto err;
1057                 }
1058
1059                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
1060                           peer->hard_header_len -
1061                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1062                 if (peer->mtu > max_mtu) {
1063                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1064                         err = -ERANGE;
1065                         goto err;
1066                 }
1067
1068                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1069                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1070                         err = -ENOSPC;
1071                         goto err;
1072                 }
1073
1074                 if (dev->flags & IFF_UP) {
1075                         err = veth_enable_xdp(dev);
1076                         if (err) {
1077                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1078                                 goto err;
1079                         }
1080                 }
1081
1082                 if (!old_prog) {
1083                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1084                         peer->max_mtu = max_mtu;
1085                 }
1086         }
1087
1088         if (old_prog) {
1089                 if (!prog) {
1090                         if (dev->flags & IFF_UP)
1091                                 veth_disable_xdp(dev);
1092
1093                         if (peer) {
1094                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1095                                 peer->max_mtu = ETH_MAX_MTU;
1096                         }
1097                 }
1098                 bpf_prog_put(old_prog);
1099         }
1100
1101         if ((!!old_prog ^ !!prog) && peer)
1102                 netdev_update_features(peer);
1103
1104         return 0;
1105 err:
1106         priv->_xdp_prog = old_prog;
1107
1108         return err;
1109 }
1110
1111 static u32 veth_xdp_query(struct net_device *dev)
1112 {
1113         struct veth_priv *priv = netdev_priv(dev);
1114         const struct bpf_prog *xdp_prog;
1115
1116         xdp_prog = priv->_xdp_prog;
1117         if (xdp_prog)
1118                 return xdp_prog->aux->id;
1119
1120         return 0;
1121 }
1122
1123 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1124 {
1125         switch (xdp->command) {
1126         case XDP_SETUP_PROG:
1127                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1128         case XDP_QUERY_PROG:
1129                 xdp->prog_id = veth_xdp_query(dev);
1130                 return 0;
1131         default:
1132                 return -EINVAL;
1133         }
1134 }
1135
1136 static const struct net_device_ops veth_netdev_ops = {
1137         .ndo_init            = veth_dev_init,
1138         .ndo_open            = veth_open,
1139         .ndo_stop            = veth_close,
1140         .ndo_start_xmit      = veth_xmit,
1141         .ndo_get_stats64     = veth_get_stats64,
1142         .ndo_set_rx_mode     = veth_set_multicast_list,
1143         .ndo_set_mac_address = eth_mac_addr,
1144 #ifdef CONFIG_NET_POLL_CONTROLLER
1145         .ndo_poll_controller    = veth_poll_controller,
1146 #endif
1147         .ndo_get_iflink         = veth_get_iflink,
1148         .ndo_fix_features       = veth_fix_features,
1149         .ndo_features_check     = passthru_features_check,
1150         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1151         .ndo_bpf                = veth_xdp,
1152         .ndo_xdp_xmit           = veth_xdp_xmit,
1153 };
1154
1155 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1156                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1157                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1158                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1159                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1160
1161 static void veth_setup(struct net_device *dev)
1162 {
1163         ether_setup(dev);
1164
1165         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1166         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1167         dev->priv_flags |= IFF_NO_QUEUE;
1168         dev->priv_flags |= IFF_PHONY_HEADROOM;
1169
1170         dev->netdev_ops = &veth_netdev_ops;
1171         dev->ethtool_ops = &veth_ethtool_ops;
1172         dev->features |= NETIF_F_LLTX;
1173         dev->features |= VETH_FEATURES;
1174         dev->vlan_features = dev->features &
1175                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1176                                NETIF_F_HW_VLAN_STAG_TX |
1177                                NETIF_F_HW_VLAN_CTAG_RX |
1178                                NETIF_F_HW_VLAN_STAG_RX);
1179         dev->needs_free_netdev = true;
1180         dev->priv_destructor = veth_dev_free;
1181         dev->max_mtu = ETH_MAX_MTU;
1182
1183         dev->hw_features = VETH_FEATURES;
1184         dev->hw_enc_features = VETH_FEATURES;
1185         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1186 }
1187
1188 /*
1189  * netlink interface
1190  */
1191
1192 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1193                          struct netlink_ext_ack *extack)
1194 {
1195         if (tb[IFLA_ADDRESS]) {
1196                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1197                         return -EINVAL;
1198                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1199                         return -EADDRNOTAVAIL;
1200         }
1201         if (tb[IFLA_MTU]) {
1202                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1203                         return -EINVAL;
1204         }
1205         return 0;
1206 }
1207
1208 static struct rtnl_link_ops veth_link_ops;
1209
1210 static int veth_newlink(struct net *src_net, struct net_device *dev,
1211                         struct nlattr *tb[], struct nlattr *data[],
1212                         struct netlink_ext_ack *extack)
1213 {
1214         int err;
1215         struct net_device *peer;
1216         struct veth_priv *priv;
1217         char ifname[IFNAMSIZ];
1218         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1219         unsigned char name_assign_type;
1220         struct ifinfomsg *ifmp;
1221         struct net *net;
1222
1223         /*
1224          * create and register peer first
1225          */
1226         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1227                 struct nlattr *nla_peer;
1228
1229                 nla_peer = data[VETH_INFO_PEER];
1230                 ifmp = nla_data(nla_peer);
1231                 err = rtnl_nla_parse_ifla(peer_tb,
1232                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1233                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1234                                           NULL);
1235                 if (err < 0)
1236                         return err;
1237
1238                 err = veth_validate(peer_tb, NULL, extack);
1239                 if (err < 0)
1240                         return err;
1241
1242                 tbp = peer_tb;
1243         } else {
1244                 ifmp = NULL;
1245                 tbp = tb;
1246         }
1247
1248         if (ifmp && tbp[IFLA_IFNAME]) {
1249                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1250                 name_assign_type = NET_NAME_USER;
1251         } else {
1252                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1253                 name_assign_type = NET_NAME_ENUM;
1254         }
1255
1256         net = rtnl_link_get_net(src_net, tbp);
1257         if (IS_ERR(net))
1258                 return PTR_ERR(net);
1259
1260         peer = rtnl_create_link(net, ifname, name_assign_type,
1261                                 &veth_link_ops, tbp, extack);
1262         if (IS_ERR(peer)) {
1263                 put_net(net);
1264                 return PTR_ERR(peer);
1265         }
1266
1267         if (!ifmp || !tbp[IFLA_ADDRESS])
1268                 eth_hw_addr_random(peer);
1269
1270         if (ifmp && (dev->ifindex != 0))
1271                 peer->ifindex = ifmp->ifi_index;
1272
1273         peer->gso_max_size = dev->gso_max_size;
1274         peer->gso_max_segs = dev->gso_max_segs;
1275
1276         err = register_netdevice(peer);
1277         put_net(net);
1278         net = NULL;
1279         if (err < 0)
1280                 goto err_register_peer;
1281
1282         netif_carrier_off(peer);
1283
1284         err = rtnl_configure_link(peer, ifmp);
1285         if (err < 0)
1286                 goto err_configure_peer;
1287
1288         /*
1289          * register dev last
1290          *
1291          * note, that since we've registered new device the dev's name
1292          * should be re-allocated
1293          */
1294
1295         if (tb[IFLA_ADDRESS] == NULL)
1296                 eth_hw_addr_random(dev);
1297
1298         if (tb[IFLA_IFNAME])
1299                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1300         else
1301                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1302
1303         err = register_netdevice(dev);
1304         if (err < 0)
1305                 goto err_register_dev;
1306
1307         netif_carrier_off(dev);
1308
1309         /*
1310          * tie the deviced together
1311          */
1312
1313         priv = netdev_priv(dev);
1314         rcu_assign_pointer(priv->peer, peer);
1315
1316         priv = netdev_priv(peer);
1317         rcu_assign_pointer(priv->peer, dev);
1318
1319         return 0;
1320
1321 err_register_dev:
1322         /* nothing to do */
1323 err_configure_peer:
1324         unregister_netdevice(peer);
1325         return err;
1326
1327 err_register_peer:
1328         free_netdev(peer);
1329         return err;
1330 }
1331
1332 static void veth_dellink(struct net_device *dev, struct list_head *head)
1333 {
1334         struct veth_priv *priv;
1335         struct net_device *peer;
1336
1337         priv = netdev_priv(dev);
1338         peer = rtnl_dereference(priv->peer);
1339
1340         /* Note : dellink() is called from default_device_exit_batch(),
1341          * before a rcu_synchronize() point. The devices are guaranteed
1342          * not being freed before one RCU grace period.
1343          */
1344         RCU_INIT_POINTER(priv->peer, NULL);
1345         unregister_netdevice_queue(dev, head);
1346
1347         if (peer) {
1348                 priv = netdev_priv(peer);
1349                 RCU_INIT_POINTER(priv->peer, NULL);
1350                 unregister_netdevice_queue(peer, head);
1351         }
1352 }
1353
1354 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1355         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1356 };
1357
1358 static struct net *veth_get_link_net(const struct net_device *dev)
1359 {
1360         struct veth_priv *priv = netdev_priv(dev);
1361         struct net_device *peer = rtnl_dereference(priv->peer);
1362
1363         return peer ? dev_net(peer) : dev_net(dev);
1364 }
1365
1366 static struct rtnl_link_ops veth_link_ops = {
1367         .kind           = DRV_NAME,
1368         .priv_size      = sizeof(struct veth_priv),
1369         .setup          = veth_setup,
1370         .validate       = veth_validate,
1371         .newlink        = veth_newlink,
1372         .dellink        = veth_dellink,
1373         .policy         = veth_policy,
1374         .maxtype        = VETH_INFO_MAX,
1375         .get_link_net   = veth_get_link_net,
1376 };
1377
1378 /*
1379  * init/fini
1380  */
1381
1382 static __init int veth_init(void)
1383 {
1384         return rtnl_link_register(&veth_link_ops);
1385 }
1386
1387 static __exit void veth_exit(void)
1388 {
1389         rtnl_link_unregister(&veth_link_ops);
1390 }
1391
1392 module_init(veth_init);
1393 module_exit(veth_exit);
1394
1395 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1396 MODULE_LICENSE("GPL v2");
1397 MODULE_ALIAS_RTNL_LINK(DRV_NAME);