drivers/net/veth.c

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