drivers/net/veth.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  drivers/net/veth.c
   4  *
   5  *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
   6  *
   7  * Author: Pavel Emelianov <xemul@openvz.org>
   8  * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
   9  *
  10  */
  11
  12 #include <linux/netdevice.h>
  13 #include <linux/slab.h>
  14 #include <linux/ethtool.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/u64_stats_sync.h>
  17
  18 #include <net/rtnetlink.h>
  19 #include <net/dst.h>
  20 #include <net/xfrm.h>
  21 #include <net/xdp.h>
  22 #include <linux/veth.h>
  23 #include <linux/module.h>
  24 #include <linux/bpf.h>
  25 #include <linux/filter.h>
  26 #include <linux/ptr_ring.h>
  27 #include <linux/bpf_trace.h>
  28 #include <linux/net_tstamp.h>
  29
  30 #define DRV_NAME        "veth"
  31 #define DRV_VERSION     "1.0"
  32
  33 #define VETH_XDP_FLAG           BIT(0)
  34 #define VETH_RING_SIZE          256
  35 #define VETH_XDP_HEADROOM       (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
  36
  37 /* Separating two types of XDP xmit */
  38 #define VETH_XDP_TX             BIT(0)
  39 #define VETH_XDP_REDIR          BIT(1)
  40
  41 #define VETH_XDP_TX_BULK_SIZE   16
  42
  43 struct veth_rq_stats {
  44         u64                     xdp_packets;
  45         u64                     xdp_bytes;
  46         u64                     xdp_drops;
  47         struct u64_stats_sync   syncp;
  48 };
  49
  50 struct veth_rq {
  51         struct napi_struct      xdp_napi;
  52         struct net_device       *dev;
  53         struct bpf_prog __rcu   *xdp_prog;
  54         struct xdp_mem_info     xdp_mem;
  55         struct veth_rq_stats    stats;
  56         bool                    rx_notify_masked;
  57         struct ptr_ring         xdp_ring;
  58         struct xdp_rxq_info     xdp_rxq;
  59 };
  60
  61 struct veth_priv {
  62         struct net_device __rcu *peer;
  63         atomic64_t              dropped;
  64         struct bpf_prog         *_xdp_prog;
  65         struct veth_rq          *rq;
  66         unsigned int            requested_headroom;
  67 };
  68
  69 struct veth_xdp_tx_bq {
  70         struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
  71         unsigned int count;
  72 };
  73
  74 /*
  75  * ethtool interface
  76  */
  77
  78 struct veth_q_stat_desc {
  79         char    desc[ETH_GSTRING_LEN];
  80         size_t  offset;
  81 };
  82
  83 #define VETH_RQ_STAT(m) offsetof(struct veth_rq_stats, m)
  84
  85 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  86         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  87         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  88         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
  89 };
  90
  91 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
  92
  93 static struct {
  94         const char string[ETH_GSTRING_LEN];
  95 } ethtool_stats_keys[] = {
  96         { "peer_ifindex" },
  97 };
  98
  99 static int veth_get_link_ksettings(struct net_device *dev,
 100                                    struct ethtool_link_ksettings *cmd)
 101 {
 102         cmd->base.speed         = SPEED_10000;
 103         cmd->base.duplex        = DUPLEX_FULL;
 104         cmd->base.port          = PORT_TP;
 105         cmd->base.autoneg       = AUTONEG_DISABLE;
 106         return 0;
 107 }
 108
 109 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 110 {
 111         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 112         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 113 }
 114
 115 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 116 {
 117         char *p = (char *)buf;
 118         int i, j;
 119
 120         switch(stringset) {
 121         case ETH_SS_STATS:
 122                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 123                 p += sizeof(ethtool_stats_keys);
 124                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 125                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 126                                 snprintf(p, ETH_GSTRING_LEN,
 127                                          "rx_queue_%u_%.11s",
 128                                          i, veth_rq_stats_desc[j].desc);
 129                                 p += ETH_GSTRING_LEN;
 130                         }
 131                 }
 132                 break;
 133         }
 134 }
 135
 136 static int veth_get_sset_count(struct net_device *dev, int sset)
 137 {
 138         switch (sset) {
 139         case ETH_SS_STATS:
 140                 return ARRAY_SIZE(ethtool_stats_keys) +
 141                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues;
 142         default:
 143                 return -EOPNOTSUPP;
 144         }
 145 }
 146
 147 static void veth_get_ethtool_stats(struct net_device *dev,
 148                 struct ethtool_stats *stats, u64 *data)
 149 {
 150         struct veth_priv *priv = netdev_priv(dev);
 151         struct net_device *peer = rtnl_dereference(priv->peer);
 152         int i, j, idx;
 153
 154         data[0] = peer ? peer->ifindex : 0;
 155         idx = 1;
 156         for (i = 0; i < dev->real_num_rx_queues; i++) {
 157                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 158                 const void *stats_base = (void *)rq_stats;
 159                 unsigned int start;
 160                 size_t offset;
 161
 162                 do {
 163                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 164                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 165                                 offset = veth_rq_stats_desc[j].offset;
 166                                 data[idx + j] = *(u64 *)(stats_base + offset);
 167                         }
 168                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 169                 idx += VETH_RQ_STATS_LEN;
 170         }
 171 }
 172
 173 static const struct ethtool_ops veth_ethtool_ops = {
 174         .get_drvinfo            = veth_get_drvinfo,
 175         .get_link               = ethtool_op_get_link,
 176         .get_strings            = veth_get_strings,
 177         .get_sset_count         = veth_get_sset_count,
 178         .get_ethtool_stats      = veth_get_ethtool_stats,
 179         .get_link_ksettings     = veth_get_link_ksettings,
 180         .get_ts_info            = ethtool_op_get_ts_info,
 181 };
 182
 183 /* general routines */
 184
 185 static bool veth_is_xdp_frame(void *ptr)
 186 {
 187         return (unsigned long)ptr & VETH_XDP_FLAG;
 188 }
 189
 190 static void *veth_ptr_to_xdp(void *ptr)
 191 {
 192         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 193 }
 194
 195 static void *veth_xdp_to_ptr(void *ptr)
 196 {
 197         return (void *)((unsigned long)ptr | VETH_XDP_FLAG);
 198 }
 199
 200 static void veth_ptr_free(void *ptr)
 201 {
 202         if (veth_is_xdp_frame(ptr))
 203                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 204         else
 205                 kfree_skb(ptr);
 206 }
 207
 208 static void __veth_xdp_flush(struct veth_rq *rq)
 209 {
 210         /* Write ptr_ring before reading rx_notify_masked */
 211         smp_mb();
 212         if (!rq->rx_notify_masked) {
 213                 rq->rx_notify_masked = true;
 214                 napi_schedule(&rq->xdp_napi);
 215         }
 216 }
 217
 218 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 219 {
 220         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 221                 dev_kfree_skb_any(skb);
 222                 return NET_RX_DROP;
 223         }
 224
 225         return NET_RX_SUCCESS;
 226 }
 227
 228 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 229                             struct veth_rq *rq, bool xdp)
 230 {
 231         return __dev_forward_skb(dev, skb) ?: xdp ?
 232                 veth_xdp_rx(rq, skb) :
 233                 netif_rx(skb);
 234 }
 235
 236 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 237 {
 238         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 239         struct veth_rq *rq = NULL;
 240         struct net_device *rcv;
 241         int length = skb->len;
 242         bool rcv_xdp = false;
 243         int rxq;
 244
 245         rcu_read_lock();
 246         rcv = rcu_dereference(priv->peer);
 247         if (unlikely(!rcv)) {
 248                 kfree_skb(skb);
 249                 goto drop;
 250         }
 251
 252         rcv_priv = netdev_priv(rcv);
 253         rxq = skb_get_queue_mapping(skb);
 254         if (rxq < rcv->real_num_rx_queues) {
 255                 rq = &rcv_priv->rq[rxq];
 256                 rcv_xdp = rcu_access_pointer(rq->xdp_prog);
 257                 if (rcv_xdp)
 258                         skb_record_rx_queue(skb, rxq);
 259         }
 260
 261         skb_tx_timestamp(skb);
 262         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 263                 if (!rcv_xdp)
 264                         dev_lstats_add(dev, length);
 265         } else {
 266 drop:
 267                 atomic64_inc(&priv->dropped);
 268         }
 269
 270         if (rcv_xdp)
 271                 __veth_xdp_flush(rq);
 272
 273         rcu_read_unlock();
 274
 275         return NETDEV_TX_OK;
 276 }
 277
 278 static u64 veth_stats_tx(struct net_device *dev, u64 *packets, u64 *bytes)
 279 {
 280         struct veth_priv *priv = netdev_priv(dev);
 281
 282         dev_lstats_read(dev, packets, bytes);
 283         return atomic64_read(&priv->dropped);
 284 }
 285
 286 static void veth_stats_rx(struct veth_rq_stats *result, struct net_device *dev)
 287 {
 288         struct veth_priv *priv = netdev_priv(dev);
 289         int i;
 290
 291         result->xdp_packets = 0;
 292         result->xdp_bytes = 0;
 293         result->xdp_drops = 0;
 294         for (i = 0; i < dev->num_rx_queues; i++) {
 295                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 296                 u64 packets, bytes, drops;
 297                 unsigned int start;
 298
 299                 do {
 300                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 301                         packets = stats->xdp_packets;
 302                         bytes = stats->xdp_bytes;
 303                         drops = stats->xdp_drops;
 304                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 305                 result->xdp_packets += packets;
 306                 result->xdp_bytes += bytes;
 307                 result->xdp_drops += drops;
 308         }
 309 }
 310
 311 static void veth_get_stats64(struct net_device *dev,
 312                              struct rtnl_link_stats64 *tot)
 313 {
 314         struct veth_priv *priv = netdev_priv(dev);
 315         struct net_device *peer;
 316         struct veth_rq_stats rx;
 317         u64 packets, bytes;
 318
 319         tot->tx_dropped = veth_stats_tx(dev, &packets, &bytes);
 320         tot->tx_bytes = bytes;
 321         tot->tx_packets = packets;
 322
 323         veth_stats_rx(&rx, dev);
 324         tot->rx_dropped = rx.xdp_drops;
 325         tot->rx_bytes = rx.xdp_bytes;
 326         tot->rx_packets = rx.xdp_packets;
 327
 328         rcu_read_lock();
 329         peer = rcu_dereference(priv->peer);
 330         if (peer) {
 331                 tot->rx_dropped += veth_stats_tx(peer, &packets, &bytes);
 332                 tot->rx_bytes += bytes;
 333                 tot->rx_packets += packets;
 334
 335                 veth_stats_rx(&rx, peer);
 336                 tot->tx_bytes += rx.xdp_bytes;
 337                 tot->tx_packets += rx.xdp_packets;
 338         }
 339         rcu_read_unlock();
 340 }
 341
 342 /* fake multicast ability */
 343 static void veth_set_multicast_list(struct net_device *dev)
 344 {
 345 }
 346
 347 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 348                                       int buflen)
 349 {
 350         struct sk_buff *skb;
 351
 352         if (!buflen) {
 353                 buflen = SKB_DATA_ALIGN(headroom + len) +
 354                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 355         }
 356         skb = build_skb(head, buflen);
 357         if (!skb)
 358                 return NULL;
 359
 360         skb_reserve(skb, headroom);
 361         skb_put(skb, len);
 362
 363         return skb;
 364 }
 365
 366 static int veth_select_rxq(struct net_device *dev)
 367 {
 368         return smp_processor_id() % dev->real_num_rx_queues;
 369 }
 370
 371 static int veth_xdp_xmit(struct net_device *dev, int n,
 372                          struct xdp_frame **frames, u32 flags)
 373 {
 374         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 375         struct net_device *rcv;
 376         int i, ret, drops = n;
 377         unsigned int max_len;
 378         struct veth_rq *rq;
 379
 380         rcu_read_lock();
 381         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) {
 382                 ret = -EINVAL;
 383                 goto drop;
 384         }
 385
 386         rcv = rcu_dereference(priv->peer);
 387         if (unlikely(!rcv)) {
 388                 ret = -ENXIO;
 389                 goto drop;
 390         }
 391
 392         rcv_priv = netdev_priv(rcv);
 393         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 394         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 395          * side. This means an XDP program is loaded on the peer and the peer
 396          * device is up.
 397          */
 398         if (!rcu_access_pointer(rq->xdp_prog)) {
 399                 ret = -ENXIO;
 400                 goto drop;
 401         }
 402
 403         drops = 0;
 404         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 405
 406         spin_lock(&rq->xdp_ring.producer_lock);
 407         for (i = 0; i < n; i++) {
 408                 struct xdp_frame *frame = frames[i];
 409                 void *ptr = veth_xdp_to_ptr(frame);
 410
 411                 if (unlikely(frame->len > max_len ||
 412                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 413                         xdp_return_frame_rx_napi(frame);
 414                         drops++;
 415                 }
 416         }
 417         spin_unlock(&rq->xdp_ring.producer_lock);
 418
 419         if (flags & XDP_XMIT_FLUSH)
 420                 __veth_xdp_flush(rq);
 421
 422         if (likely(!drops)) {
 423                 rcu_read_unlock();
 424                 return n;
 425         }
 426
 427         ret = n - drops;
 428 drop:
 429         rcu_read_unlock();
 430         atomic64_add(drops, &priv->dropped);
 431
 432         return ret;
 433 }
 434
 435 static void veth_xdp_flush_bq(struct net_device *dev, struct veth_xdp_tx_bq *bq)
 436 {
 437         int sent, i, err = 0;
 438
 439         sent = veth_xdp_xmit(dev, bq->count, bq->q, 0);
 440         if (sent < 0) {
 441                 err = sent;
 442                 sent = 0;
 443                 for (i = 0; i < bq->count; i++)
 444                         xdp_return_frame(bq->q[i]);
 445         }
 446         trace_xdp_bulk_tx(dev, sent, bq->count - sent, err);
 447
 448         bq->count = 0;
 449 }
 450
 451 static void veth_xdp_flush(struct net_device *dev, struct veth_xdp_tx_bq *bq)
 452 {
 453         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 454         struct net_device *rcv;
 455         struct veth_rq *rq;
 456
 457         rcu_read_lock();
 458         veth_xdp_flush_bq(dev, bq);
 459         rcv = rcu_dereference(priv->peer);
 460         if (unlikely(!rcv))
 461                 goto out;
 462
 463         rcv_priv = netdev_priv(rcv);
 464         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 465         /* xdp_ring is initialized on receive side? */
 466         if (unlikely(!rcu_access_pointer(rq->xdp_prog)))
 467                 goto out;
 468
 469         __veth_xdp_flush(rq);
 470 out:
 471         rcu_read_unlock();
 472 }
 473
 474 static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp,
 475                        struct veth_xdp_tx_bq *bq)
 476 {
 477         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
 478
 479         if (unlikely(!frame))
 480                 return -EOVERFLOW;
 481
 482         if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
 483                 veth_xdp_flush_bq(dev, bq);
 484
 485         bq->q[bq->count++] = frame;
 486
 487         return 0;
 488 }
 489
 490 static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 491                                         struct xdp_frame *frame,
 492                                         unsigned int *xdp_xmit,
 493                                         struct veth_xdp_tx_bq *bq)
 494 {
 495         void *hard_start = frame->data - frame->headroom;
 496         void *head = hard_start - sizeof(struct xdp_frame);
 497         int len = frame->len, delta = 0;
 498         struct xdp_frame orig_frame;
 499         struct bpf_prog *xdp_prog;
 500         unsigned int headroom;
 501         struct sk_buff *skb;
 502
 503         rcu_read_lock();
 504         xdp_prog = rcu_dereference(rq->xdp_prog);
 505         if (likely(xdp_prog)) {
 506                 struct xdp_buff xdp;
 507                 u32 act;
 508
 509                 xdp.data_hard_start = hard_start;
 510                 xdp.data = frame->data;
 511                 xdp.data_end = frame->data + frame->len;
 512                 xdp.data_meta = frame->data - frame->metasize;
 513                 xdp.rxq = &rq->xdp_rxq;
 514
 515                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 516
 517                 switch (act) {
 518                 case XDP_PASS:
 519                         delta = frame->data - xdp.data;
 520                         len = xdp.data_end - xdp.data;
 521                         break;
 522                 case XDP_TX:
 523                         orig_frame = *frame;
 524                         xdp.data_hard_start = head;
 525                         xdp.rxq->mem = frame->mem;
 526                         if (unlikely(veth_xdp_tx(rq->dev, &xdp, bq) < 0)) {
 527                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 528                                 frame = &orig_frame;
 529                                 goto err_xdp;
 530                         }
 531                         *xdp_xmit |= VETH_XDP_TX;
 532                         rcu_read_unlock();
 533                         goto xdp_xmit;
 534                 case XDP_REDIRECT:
 535                         orig_frame = *frame;
 536                         xdp.data_hard_start = head;
 537                         xdp.rxq->mem = frame->mem;
 538                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 539                                 frame = &orig_frame;
 540                                 goto err_xdp;
 541                         }
 542                         *xdp_xmit |= VETH_XDP_REDIR;
 543                         rcu_read_unlock();
 544                         goto xdp_xmit;
 545                 default:
 546                         bpf_warn_invalid_xdp_action(act);
 547                         /* fall through */
 548                 case XDP_ABORTED:
 549                         trace_xdp_exception(rq->dev, xdp_prog, act);
 550                         /* fall through */
 551                 case XDP_DROP:
 552                         goto err_xdp;
 553                 }
 554         }
 555         rcu_read_unlock();
 556
 557         headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
 558         skb = veth_build_skb(head, headroom, len, 0);
 559         if (!skb) {
 560                 xdp_return_frame(frame);
 561                 goto err;
 562         }
 563
 564         xdp_release_frame(frame);
 565         xdp_scrub_frame(frame);
 566         skb->protocol = eth_type_trans(skb, rq->dev);
 567 err:
 568         return skb;
 569 err_xdp:
 570         rcu_read_unlock();
 571         xdp_return_frame(frame);
 572 xdp_xmit:
 573         return NULL;
 574 }
 575
 576 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq, struct sk_buff *skb,
 577                                         unsigned int *xdp_xmit,
 578                                         struct veth_xdp_tx_bq *bq)
 579 {
 580         u32 pktlen, headroom, act, metalen;
 581         void *orig_data, *orig_data_end;
 582         struct bpf_prog *xdp_prog;
 583         int mac_len, delta, off;
 584         struct xdp_buff xdp;
 585
 586         skb_orphan(skb);
 587
 588         rcu_read_lock();
 589         xdp_prog = rcu_dereference(rq->xdp_prog);
 590         if (unlikely(!xdp_prog)) {
 591                 rcu_read_unlock();
 592                 goto out;
 593         }
 594
 595         mac_len = skb->data - skb_mac_header(skb);
 596         pktlen = skb->len + mac_len;
 597         headroom = skb_headroom(skb) - mac_len;
 598
 599         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 600             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 601                 struct sk_buff *nskb;
 602                 int size, head_off;
 603                 void *head, *start;
 604                 struct page *page;
 605
 606                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 607                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 608                 if (size > PAGE_SIZE)
 609                         goto drop;
 610
 611                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 612                 if (!page)
 613                         goto drop;
 614
 615                 head = page_address(page);
 616                 start = head + VETH_XDP_HEADROOM;
 617                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 618                         page_frag_free(head);
 619                         goto drop;
 620                 }
 621
 622                 nskb = veth_build_skb(head,
 623                                       VETH_XDP_HEADROOM + mac_len, skb->len,
 624                                       PAGE_SIZE);
 625                 if (!nskb) {
 626                         page_frag_free(head);
 627                         goto drop;
 628                 }
 629
 630                 skb_copy_header(nskb, skb);
 631                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 632                 skb_headers_offset_update(nskb, head_off);
 633                 consume_skb(skb);
 634                 skb = nskb;
 635         }
 636
 637         xdp.data_hard_start = skb->head;
 638         xdp.data = skb_mac_header(skb);
 639         xdp.data_end = xdp.data + pktlen;
 640         xdp.data_meta = xdp.data;
 641         xdp.rxq = &rq->xdp_rxq;
 642         orig_data = xdp.data;
 643         orig_data_end = xdp.data_end;
 644
 645         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 646
 647         switch (act) {
 648         case XDP_PASS:
 649                 break;
 650         case XDP_TX:
 651                 get_page(virt_to_page(xdp.data));
 652                 consume_skb(skb);
 653                 xdp.rxq->mem = rq->xdp_mem;
 654                 if (unlikely(veth_xdp_tx(rq->dev, &xdp, bq) < 0)) {
 655                         trace_xdp_exception(rq->dev, xdp_prog, act);
 656                         goto err_xdp;
 657                 }
 658                 *xdp_xmit |= VETH_XDP_TX;
 659                 rcu_read_unlock();
 660                 goto xdp_xmit;
 661         case XDP_REDIRECT:
 662                 get_page(virt_to_page(xdp.data));
 663                 consume_skb(skb);
 664                 xdp.rxq->mem = rq->xdp_mem;
 665                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog))
 666                         goto err_xdp;
 667                 *xdp_xmit |= VETH_XDP_REDIR;
 668                 rcu_read_unlock();
 669                 goto xdp_xmit;
 670         default:
 671                 bpf_warn_invalid_xdp_action(act);
 672                 /* fall through */
 673         case XDP_ABORTED:
 674                 trace_xdp_exception(rq->dev, xdp_prog, act);
 675                 /* fall through */
 676         case XDP_DROP:
 677                 goto drop;
 678         }
 679         rcu_read_unlock();
 680
 681         delta = orig_data - xdp.data;
 682         off = mac_len + delta;
 683         if (off > 0)
 684                 __skb_push(skb, off);
 685         else if (off < 0)
 686                 __skb_pull(skb, -off);
 687         skb->mac_header -= delta;
 688         off = xdp.data_end - orig_data_end;
 689         if (off != 0)
 690                 __skb_put(skb, off);
 691         skb->protocol = eth_type_trans(skb, rq->dev);
 692
 693         metalen = xdp.data - xdp.data_meta;
 694         if (metalen)
 695                 skb_metadata_set(skb, metalen);
 696 out:
 697         return skb;
 698 drop:
 699         rcu_read_unlock();
 700         kfree_skb(skb);
 701         return NULL;
 702 err_xdp:
 703         rcu_read_unlock();
 704         page_frag_free(xdp.data);
 705 xdp_xmit:
 706         return NULL;
 707 }
 708
 709 static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit,
 710                         struct veth_xdp_tx_bq *bq)
 711 {
 712         int i, done = 0, drops = 0, bytes = 0;
 713
 714         for (i = 0; i < budget; i++) {
 715                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 716                 unsigned int xdp_xmit_one = 0;
 717                 struct sk_buff *skb;
 718
 719                 if (!ptr)
 720                         break;
 721
 722                 if (veth_is_xdp_frame(ptr)) {
 723                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 724
 725                         bytes += frame->len;
 726                         skb = veth_xdp_rcv_one(rq, frame, &xdp_xmit_one, bq);
 727                 } else {
 728                         skb = ptr;
 729                         bytes += skb->len;
 730                         skb = veth_xdp_rcv_skb(rq, skb, &xdp_xmit_one, bq);
 731                 }
 732                 *xdp_xmit |= xdp_xmit_one;
 733
 734                 if (skb)
 735                         napi_gro_receive(&rq->xdp_napi, skb);
 736                 else if (!xdp_xmit_one)
 737                         drops++;
 738
 739                 done++;
 740         }
 741
 742         u64_stats_update_begin(&rq->stats.syncp);
 743         rq->stats.xdp_packets += done;
 744         rq->stats.xdp_bytes += bytes;
 745         rq->stats.xdp_drops += drops;
 746         u64_stats_update_end(&rq->stats.syncp);
 747
 748         return done;
 749 }
 750
 751 static int veth_poll(struct napi_struct *napi, int budget)
 752 {
 753         struct veth_rq *rq =
 754                 container_of(napi, struct veth_rq, xdp_napi);
 755         unsigned int xdp_xmit = 0;
 756         struct veth_xdp_tx_bq bq;
 757         int done;
 758
 759         bq.count = 0;
 760
 761         xdp_set_return_frame_no_direct();
 762         done = veth_xdp_rcv(rq, budget, &xdp_xmit, &bq);
 763
 764         if (done < budget && napi_complete_done(napi, done)) {
 765                 /* Write rx_notify_masked before reading ptr_ring */
 766                 smp_store_mb(rq->rx_notify_masked, false);
 767                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 768                         rq->rx_notify_masked = true;
 769                         napi_schedule(&rq->xdp_napi);
 770                 }
 771         }
 772
 773         if (xdp_xmit & VETH_XDP_TX)
 774                 veth_xdp_flush(rq->dev, &bq);
 775         if (xdp_xmit & VETH_XDP_REDIR)
 776                 xdp_do_flush();
 777         xdp_clear_return_frame_no_direct();
 778
 779         return done;
 780 }
 781
 782 static int veth_napi_add(struct net_device *dev)
 783 {
 784         struct veth_priv *priv = netdev_priv(dev);
 785         int err, i;
 786
 787         for (i = 0; i < dev->real_num_rx_queues; i++) {
 788                 struct veth_rq *rq = &priv->rq[i];
 789
 790                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 791                 if (err)
 792                         goto err_xdp_ring;
 793         }
 794
 795         for (i = 0; i < dev->real_num_rx_queues; i++) {
 796                 struct veth_rq *rq = &priv->rq[i];
 797
 798                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 799                 napi_enable(&rq->xdp_napi);
 800         }
 801
 802         return 0;
 803 err_xdp_ring:
 804         for (i--; i >= 0; i--)
 805                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 806
 807         return err;
 808 }
 809
 810 static void veth_napi_del(struct net_device *dev)
 811 {
 812         struct veth_priv *priv = netdev_priv(dev);
 813         int i;
 814
 815         for (i = 0; i < dev->real_num_rx_queues; i++) {
 816                 struct veth_rq *rq = &priv->rq[i];
 817
 818                 napi_disable(&rq->xdp_napi);
 819                 napi_hash_del(&rq->xdp_napi);
 820         }
 821         synchronize_net();
 822
 823         for (i = 0; i < dev->real_num_rx_queues; i++) {
 824                 struct veth_rq *rq = &priv->rq[i];
 825
 826                 netif_napi_del(&rq->xdp_napi);
 827                 rq->rx_notify_masked = false;
 828                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 829         }
 830 }
 831
 832 static int veth_enable_xdp(struct net_device *dev)
 833 {
 834         struct veth_priv *priv = netdev_priv(dev);
 835         int err, i;
 836
 837         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 838                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 839                         struct veth_rq *rq = &priv->rq[i];
 840
 841                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i);
 842                         if (err < 0)
 843                                 goto err_rxq_reg;
 844
 845                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 846                                                          MEM_TYPE_PAGE_SHARED,
 847                                                          NULL);
 848                         if (err < 0)
 849                                 goto err_reg_mem;
 850
 851                         /* Save original mem info as it can be overwritten */
 852                         rq->xdp_mem = rq->xdp_rxq.mem;
 853                 }
 854
 855                 err = veth_napi_add(dev);
 856                 if (err)
 857                         goto err_rxq_reg;
 858         }
 859
 860         for (i = 0; i < dev->real_num_rx_queues; i++)
 861                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 862
 863         return 0;
 864 err_reg_mem:
 865         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 866 err_rxq_reg:
 867         for (i--; i >= 0; i--)
 868                 xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 869
 870         return err;
 871 }
 872
 873 static void veth_disable_xdp(struct net_device *dev)
 874 {
 875         struct veth_priv *priv = netdev_priv(dev);
 876         int i;
 877
 878         for (i = 0; i < dev->real_num_rx_queues; i++)
 879                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 880         veth_napi_del(dev);
 881         for (i = 0; i < dev->real_num_rx_queues; i++) {
 882                 struct veth_rq *rq = &priv->rq[i];
 883
 884                 rq->xdp_rxq.mem = rq->xdp_mem;
 885                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 886         }
 887 }
 888
 889 static int veth_open(struct net_device *dev)
 890 {
 891         struct veth_priv *priv = netdev_priv(dev);
 892         struct net_device *peer = rtnl_dereference(priv->peer);
 893         int err;
 894
 895         if (!peer)
 896                 return -ENOTCONN;
 897
 898         if (priv->_xdp_prog) {
 899                 err = veth_enable_xdp(dev);
 900                 if (err)
 901                         return err;
 902         }
 903
 904         if (peer->flags & IFF_UP) {
 905                 netif_carrier_on(dev);
 906                 netif_carrier_on(peer);
 907         }
 908
 909         return 0;
 910 }
 911
 912 static int veth_close(struct net_device *dev)
 913 {
 914         struct veth_priv *priv = netdev_priv(dev);
 915         struct net_device *peer = rtnl_dereference(priv->peer);
 916
 917         netif_carrier_off(dev);
 918         if (peer)
 919                 netif_carrier_off(peer);
 920
 921         if (priv->_xdp_prog)
 922                 veth_disable_xdp(dev);
 923
 924         return 0;
 925 }
 926
 927 static int is_valid_veth_mtu(int mtu)
 928 {
 929         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
 930 }
 931
 932 static int veth_alloc_queues(struct net_device *dev)
 933 {
 934         struct veth_priv *priv = netdev_priv(dev);
 935         int i;
 936
 937         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
 938         if (!priv->rq)
 939                 return -ENOMEM;
 940
 941         for (i = 0; i < dev->num_rx_queues; i++) {
 942                 priv->rq[i].dev = dev;
 943                 u64_stats_init(&priv->rq[i].stats.syncp);
 944         }
 945
 946         return 0;
 947 }
 948
 949 static void veth_free_queues(struct net_device *dev)
 950 {
 951         struct veth_priv *priv = netdev_priv(dev);
 952
 953         kfree(priv->rq);
 954 }
 955
 956 static int veth_dev_init(struct net_device *dev)
 957 {
 958         int err;
 959
 960         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
 961         if (!dev->lstats)
 962                 return -ENOMEM;
 963
 964         err = veth_alloc_queues(dev);
 965         if (err) {
 966                 free_percpu(dev->lstats);
 967                 return err;
 968         }
 969
 970         return 0;
 971 }
 972
 973 static void veth_dev_free(struct net_device *dev)
 974 {
 975         veth_free_queues(dev);
 976         free_percpu(dev->lstats);
 977 }
 978
 979 #ifdef CONFIG_NET_POLL_CONTROLLER
 980 static void veth_poll_controller(struct net_device *dev)
 981 {
 982         /* veth only receives frames when its peer sends one
 983          * Since it has nothing to do with disabling irqs, we are guaranteed
 984          * never to have pending data when we poll for it so
 985          * there is nothing to do here.
 986          *
 987          * We need this though so netpoll recognizes us as an interface that
 988          * supports polling, which enables bridge devices in virt setups to
 989          * still use netconsole
 990          */
 991 }
 992 #endif  /* CONFIG_NET_POLL_CONTROLLER */
 993
 994 static int veth_get_iflink(const struct net_device *dev)
 995 {
 996         struct veth_priv *priv = netdev_priv(dev);
 997         struct net_device *peer;
 998         int iflink;
 999
1000         rcu_read_lock();
1001         peer = rcu_dereference(priv->peer);
1002         iflink = peer ? peer->ifindex : 0;
1003         rcu_read_unlock();
1004
1005         return iflink;
1006 }
1007
1008 static netdev_features_t veth_fix_features(struct net_device *dev,
1009                                            netdev_features_t features)
1010 {
1011         struct veth_priv *priv = netdev_priv(dev);
1012         struct net_device *peer;
1013
1014         peer = rtnl_dereference(priv->peer);
1015         if (peer) {
1016                 struct veth_priv *peer_priv = netdev_priv(peer);
1017
1018                 if (peer_priv->_xdp_prog)
1019                         features &= ~NETIF_F_GSO_SOFTWARE;
1020         }
1021
1022         return features;
1023 }
1024
1025 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1026 {
1027         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1028         struct net_device *peer;
1029
1030         if (new_hr < 0)
1031                 new_hr = 0;
1032
1033         rcu_read_lock();
1034         peer = rcu_dereference(priv->peer);
1035         if (unlikely(!peer))
1036                 goto out;
1037
1038         peer_priv = netdev_priv(peer);
1039         priv->requested_headroom = new_hr;
1040         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1041         dev->needed_headroom = new_hr;
1042         peer->needed_headroom = new_hr;
1043
1044 out:
1045         rcu_read_unlock();
1046 }
1047
1048 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1049                         struct netlink_ext_ack *extack)
1050 {
1051         struct veth_priv *priv = netdev_priv(dev);
1052         struct bpf_prog *old_prog;
1053         struct net_device *peer;
1054         unsigned int max_mtu;
1055         int err;
1056
1057         old_prog = priv->_xdp_prog;
1058         priv->_xdp_prog = prog;
1059         peer = rtnl_dereference(priv->peer);
1060
1061         if (prog) {
1062                 if (!peer) {
1063                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1064                         err = -ENOTCONN;
1065                         goto err;
1066                 }
1067
1068                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
1069                           peer->hard_header_len -
1070                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1071                 if (peer->mtu > max_mtu) {
1072                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1073                         err = -ERANGE;
1074                         goto err;
1075                 }
1076
1077                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1078                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1079                         err = -ENOSPC;
1080                         goto err;
1081                 }
1082
1083                 if (dev->flags & IFF_UP) {
1084                         err = veth_enable_xdp(dev);
1085                         if (err) {
1086                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1087                                 goto err;
1088                         }
1089                 }
1090
1091                 if (!old_prog) {
1092                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1093                         peer->max_mtu = max_mtu;
1094                 }
1095         }
1096
1097         if (old_prog) {
1098                 if (!prog) {
1099                         if (dev->flags & IFF_UP)
1100                                 veth_disable_xdp(dev);
1101
1102                         if (peer) {
1103                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1104                                 peer->max_mtu = ETH_MAX_MTU;
1105                         }
1106                 }
1107                 bpf_prog_put(old_prog);
1108         }
1109
1110         if ((!!old_prog ^ !!prog) && peer)
1111                 netdev_update_features(peer);
1112
1113         return 0;
1114 err:
1115         priv->_xdp_prog = old_prog;
1116
1117         return err;
1118 }
1119
1120 static u32 veth_xdp_query(struct net_device *dev)
1121 {
1122         struct veth_priv *priv = netdev_priv(dev);
1123         const struct bpf_prog *xdp_prog;
1124
1125         xdp_prog = priv->_xdp_prog;
1126         if (xdp_prog)
1127                 return xdp_prog->aux->id;
1128
1129         return 0;
1130 }
1131
1132 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1133 {
1134         switch (xdp->command) {
1135         case XDP_SETUP_PROG:
1136                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1137         case XDP_QUERY_PROG:
1138                 xdp->prog_id = veth_xdp_query(dev);
1139                 return 0;
1140         default:
1141                 return -EINVAL;
1142         }
1143 }
1144
1145 static const struct net_device_ops veth_netdev_ops = {
1146         .ndo_init            = veth_dev_init,
1147         .ndo_open            = veth_open,
1148         .ndo_stop            = veth_close,
1149         .ndo_start_xmit      = veth_xmit,
1150         .ndo_get_stats64     = veth_get_stats64,
1151         .ndo_set_rx_mode     = veth_set_multicast_list,
1152         .ndo_set_mac_address = eth_mac_addr,
1153 #ifdef CONFIG_NET_POLL_CONTROLLER
1154         .ndo_poll_controller    = veth_poll_controller,
1155 #endif
1156         .ndo_get_iflink         = veth_get_iflink,
1157         .ndo_fix_features       = veth_fix_features,
1158         .ndo_features_check     = passthru_features_check,
1159         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1160         .ndo_bpf                = veth_xdp,
1161         .ndo_xdp_xmit           = veth_xdp_xmit,
1162 };
1163
1164 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1165                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1166                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1167                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1168                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1169
1170 static void veth_setup(struct net_device *dev)
1171 {
1172         ether_setup(dev);
1173
1174         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1175         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1176         dev->priv_flags |= IFF_NO_QUEUE;
1177         dev->priv_flags |= IFF_PHONY_HEADROOM;
1178
1179         dev->netdev_ops = &veth_netdev_ops;
1180         dev->ethtool_ops = &veth_ethtool_ops;
1181         dev->features |= NETIF_F_LLTX;
1182         dev->features |= VETH_FEATURES;
1183         dev->vlan_features = dev->features &
1184                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1185                                NETIF_F_HW_VLAN_STAG_TX |
1186                                NETIF_F_HW_VLAN_CTAG_RX |
1187                                NETIF_F_HW_VLAN_STAG_RX);
1188         dev->needs_free_netdev = true;
1189         dev->priv_destructor = veth_dev_free;
1190         dev->max_mtu = ETH_MAX_MTU;
1191
1192         dev->hw_features = VETH_FEATURES;
1193         dev->hw_enc_features = VETH_FEATURES;
1194         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1195 }
1196
1197 /*
1198  * netlink interface
1199  */
1200
1201 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1202                          struct netlink_ext_ack *extack)
1203 {
1204         if (tb[IFLA_ADDRESS]) {
1205                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1206                         return -EINVAL;
1207                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1208                         return -EADDRNOTAVAIL;
1209         }
1210         if (tb[IFLA_MTU]) {
1211                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1212                         return -EINVAL;
1213         }
1214         return 0;
1215 }
1216
1217 static struct rtnl_link_ops veth_link_ops;
1218
1219 static int veth_newlink(struct net *src_net, struct net_device *dev,
1220                         struct nlattr *tb[], struct nlattr *data[],
1221                         struct netlink_ext_ack *extack)
1222 {
1223         int err;
1224         struct net_device *peer;
1225         struct veth_priv *priv;
1226         char ifname[IFNAMSIZ];
1227         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1228         unsigned char name_assign_type;
1229         struct ifinfomsg *ifmp;
1230         struct net *net;
1231
1232         /*
1233          * create and register peer first
1234          */
1235         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1236                 struct nlattr *nla_peer;
1237
1238                 nla_peer = data[VETH_INFO_PEER];
1239                 ifmp = nla_data(nla_peer);
1240                 err = rtnl_nla_parse_ifla(peer_tb,
1241                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1242                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1243                                           NULL);
1244                 if (err < 0)
1245                         return err;
1246
1247                 err = veth_validate(peer_tb, NULL, extack);
1248                 if (err < 0)
1249                         return err;
1250
1251                 tbp = peer_tb;
1252         } else {
1253                 ifmp = NULL;
1254                 tbp = tb;
1255         }
1256
1257         if (ifmp && tbp[IFLA_IFNAME]) {
1258                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1259                 name_assign_type = NET_NAME_USER;
1260         } else {
1261                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1262                 name_assign_type = NET_NAME_ENUM;
1263         }
1264
1265         net = rtnl_link_get_net(src_net, tbp);
1266         if (IS_ERR(net))
1267                 return PTR_ERR(net);
1268
1269         peer = rtnl_create_link(net, ifname, name_assign_type,
1270                                 &veth_link_ops, tbp, extack);
1271         if (IS_ERR(peer)) {
1272                 put_net(net);
1273                 return PTR_ERR(peer);
1274         }
1275
1276         if (!ifmp || !tbp[IFLA_ADDRESS])
1277                 eth_hw_addr_random(peer);
1278
1279         if (ifmp && (dev->ifindex != 0))
1280                 peer->ifindex = ifmp->ifi_index;
1281
1282         peer->gso_max_size = dev->gso_max_size;
1283         peer->gso_max_segs = dev->gso_max_segs;
1284
1285         err = register_netdevice(peer);
1286         put_net(net);
1287         net = NULL;
1288         if (err < 0)
1289                 goto err_register_peer;
1290
1291         netif_carrier_off(peer);
1292
1293         err = rtnl_configure_link(peer, ifmp);
1294         if (err < 0)
1295                 goto err_configure_peer;
1296
1297         /*
1298          * register dev last
1299          *
1300          * note, that since we've registered new device the dev's name
1301          * should be re-allocated
1302          */
1303
1304         if (tb[IFLA_ADDRESS] == NULL)
1305                 eth_hw_addr_random(dev);
1306
1307         if (tb[IFLA_IFNAME])
1308                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1309         else
1310                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1311
1312         err = register_netdevice(dev);
1313         if (err < 0)
1314                 goto err_register_dev;
1315
1316         netif_carrier_off(dev);
1317
1318         /*
1319          * tie the deviced together
1320          */
1321
1322         priv = netdev_priv(dev);
1323         rcu_assign_pointer(priv->peer, peer);
1324
1325         priv = netdev_priv(peer);
1326         rcu_assign_pointer(priv->peer, dev);
1327
1328         return 0;
1329
1330 err_register_dev:
1331         /* nothing to do */
1332 err_configure_peer:
1333         unregister_netdevice(peer);
1334         return err;
1335
1336 err_register_peer:
1337         free_netdev(peer);
1338         return err;
1339 }
1340
1341 static void veth_dellink(struct net_device *dev, struct list_head *head)
1342 {
1343         struct veth_priv *priv;
1344         struct net_device *peer;
1345
1346         priv = netdev_priv(dev);
1347         peer = rtnl_dereference(priv->peer);
1348
1349         /* Note : dellink() is called from default_device_exit_batch(),
1350          * before a rcu_synchronize() point. The devices are guaranteed
1351          * not being freed before one RCU grace period.
1352          */
1353         RCU_INIT_POINTER(priv->peer, NULL);
1354         unregister_netdevice_queue(dev, head);
1355
1356         if (peer) {
1357                 priv = netdev_priv(peer);
1358                 RCU_INIT_POINTER(priv->peer, NULL);
1359                 unregister_netdevice_queue(peer, head);
1360         }
1361 }
1362
1363 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1364         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1365 };
1366
1367 static struct net *veth_get_link_net(const struct net_device *dev)
1368 {
1369         struct veth_priv *priv = netdev_priv(dev);
1370         struct net_device *peer = rtnl_dereference(priv->peer);
1371
1372         return peer ? dev_net(peer) : dev_net(dev);
1373 }
1374
1375 static struct rtnl_link_ops veth_link_ops = {
1376         .kind           = DRV_NAME,
1377         .priv_size      = sizeof(struct veth_priv),
1378         .setup          = veth_setup,
1379         .validate       = veth_validate,
1380         .newlink        = veth_newlink,
1381         .dellink        = veth_dellink,
1382         .policy         = veth_policy,
1383         .maxtype        = VETH_INFO_MAX,
1384         .get_link_net   = veth_get_link_net,
1385 };
1386
1387 /*
1388  * init/fini
1389  */
1390
1391 static __init int veth_init(void)
1392 {
1393         return rtnl_link_register(&veth_link_ops);
1394 }
1395
1396 static __exit void veth_exit(void)
1397 {
1398         rtnl_link_unregister(&veth_link_ops);
1399 }
1400
1401 module_init(veth_init);
1402 module_exit(veth_exit);
1403
1404 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1405 MODULE_LICENSE("GPL v2");
1406 MODULE_ALIAS_RTNL_LINK(DRV_NAME);