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 #define VETH_XDP_TX_BULK_SIZE   16
  38
  39 struct veth_stats {
  40         u64     rx_drops;
  41         /* xdp */
  42         u64     xdp_packets;
  43         u64     xdp_bytes;
  44         u64     xdp_redirect;
  45         u64     xdp_drops;
  46         u64     xdp_tx;
  47         u64     xdp_tx_err;
  48         u64     peer_tq_xdp_xmit;
  49         u64     peer_tq_xdp_xmit_err;
  50 };
  51
  52 struct veth_rq_stats {
  53         struct veth_stats       vs;
  54         struct u64_stats_sync   syncp;
  55 };
  56
  57 struct veth_rq {
  58         struct napi_struct      xdp_napi;
  59         struct net_device       *dev;
  60         struct bpf_prog __rcu   *xdp_prog;
  61         struct xdp_mem_info     xdp_mem;
  62         struct veth_rq_stats    stats;
  63         bool                    rx_notify_masked;
  64         struct ptr_ring         xdp_ring;
  65         struct xdp_rxq_info     xdp_rxq;
  66 };
  67
  68 struct veth_priv {
  69         struct net_device __rcu *peer;
  70         atomic64_t              dropped;
  71         struct bpf_prog         *_xdp_prog;
  72         struct veth_rq          *rq;
  73         unsigned int            requested_headroom;
  74 };
  75
  76 struct veth_xdp_tx_bq {
  77         struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
  78         unsigned int count;
  79 };
  80
  81 /*
  82  * ethtool interface
  83  */
  84
  85 struct veth_q_stat_desc {
  86         char    desc[ETH_GSTRING_LEN];
  87         size_t  offset;
  88 };
  89
  90 #define VETH_RQ_STAT(m) offsetof(struct veth_stats, m)
  91
  92 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  93         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  94         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  95         { "drops",              VETH_RQ_STAT(rx_drops) },
  96         { "xdp_redirect",       VETH_RQ_STAT(xdp_redirect) },
  97         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
  98         { "xdp_tx",             VETH_RQ_STAT(xdp_tx) },
  99         { "xdp_tx_errors",      VETH_RQ_STAT(xdp_tx_err) },
 100 };
 101
 102 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
 103
 104 static const struct veth_q_stat_desc veth_tq_stats_desc[] = {
 105         { "xdp_xmit",           VETH_RQ_STAT(peer_tq_xdp_xmit) },
 106         { "xdp_xmit_errors",    VETH_RQ_STAT(peer_tq_xdp_xmit_err) },
 107 };
 108
 109 #define VETH_TQ_STATS_LEN       ARRAY_SIZE(veth_tq_stats_desc)
 110
 111 static struct {
 112         const char string[ETH_GSTRING_LEN];
 113 } ethtool_stats_keys[] = {
 114         { "peer_ifindex" },
 115 };
 116
 117 static int veth_get_link_ksettings(struct net_device *dev,
 118                                    struct ethtool_link_ksettings *cmd)
 119 {
 120         cmd->base.speed         = SPEED_10000;
 121         cmd->base.duplex        = DUPLEX_FULL;
 122         cmd->base.port          = PORT_TP;
 123         cmd->base.autoneg       = AUTONEG_DISABLE;
 124         return 0;
 125 }
 126
 127 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 128 {
 129         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 130         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 131 }
 132
 133 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 134 {
 135         char *p = (char *)buf;
 136         int i, j;
 137
 138         switch(stringset) {
 139         case ETH_SS_STATS:
 140                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 141                 p += sizeof(ethtool_stats_keys);
 142                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 143                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 144                                 snprintf(p, ETH_GSTRING_LEN,
 145                                          "rx_queue_%u_%.18s",
 146                                          i, veth_rq_stats_desc[j].desc);
 147                                 p += ETH_GSTRING_LEN;
 148                         }
 149                 }
 150                 for (i = 0; i < dev->real_num_tx_queues; i++) {
 151                         for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
 152                                 snprintf(p, ETH_GSTRING_LEN,
 153                                          "tx_queue_%u_%.18s",
 154                                          i, veth_tq_stats_desc[j].desc);
 155                                 p += ETH_GSTRING_LEN;
 156                         }
 157                 }
 158                 break;
 159         }
 160 }
 161
 162 static int veth_get_sset_count(struct net_device *dev, int sset)
 163 {
 164         switch (sset) {
 165         case ETH_SS_STATS:
 166                 return ARRAY_SIZE(ethtool_stats_keys) +
 167                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues +
 168                        VETH_TQ_STATS_LEN * dev->real_num_tx_queues;
 169         default:
 170                 return -EOPNOTSUPP;
 171         }
 172 }
 173
 174 static void veth_get_ethtool_stats(struct net_device *dev,
 175                 struct ethtool_stats *stats, u64 *data)
 176 {
 177         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 178         struct net_device *peer = rtnl_dereference(priv->peer);
 179         int i, j, idx;
 180
 181         data[0] = peer ? peer->ifindex : 0;
 182         idx = 1;
 183         for (i = 0; i < dev->real_num_rx_queues; i++) {
 184                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 185                 const void *stats_base = (void *)&rq_stats->vs;
 186                 unsigned int start;
 187                 size_t offset;
 188
 189                 do {
 190                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 191                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 192                                 offset = veth_rq_stats_desc[j].offset;
 193                                 data[idx + j] = *(u64 *)(stats_base + offset);
 194                         }
 195                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 196                 idx += VETH_RQ_STATS_LEN;
 197         }
 198
 199         if (!peer)
 200                 return;
 201
 202         rcv_priv = netdev_priv(peer);
 203         for (i = 0; i < peer->real_num_rx_queues; i++) {
 204                 const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
 205                 const void *base = (void *)&rq_stats->vs;
 206                 unsigned int start, tx_idx = idx;
 207                 size_t offset;
 208
 209                 tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
 210                 do {
 211                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 212                         for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
 213                                 offset = veth_tq_stats_desc[j].offset;
 214                                 data[tx_idx + j] += *(u64 *)(base + offset);
 215                         }
 216                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 217         }
 218 }
 219
 220 static const struct ethtool_ops veth_ethtool_ops = {
 221         .get_drvinfo            = veth_get_drvinfo,
 222         .get_link               = ethtool_op_get_link,
 223         .get_strings            = veth_get_strings,
 224         .get_sset_count         = veth_get_sset_count,
 225         .get_ethtool_stats      = veth_get_ethtool_stats,
 226         .get_link_ksettings     = veth_get_link_ksettings,
 227         .get_ts_info            = ethtool_op_get_ts_info,
 228 };
 229
 230 /* general routines */
 231
 232 static bool veth_is_xdp_frame(void *ptr)
 233 {
 234         return (unsigned long)ptr & VETH_XDP_FLAG;
 235 }
 236
 237 static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
 238 {
 239         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 240 }
 241
 242 static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
 243 {
 244         return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
 245 }
 246
 247 static void veth_ptr_free(void *ptr)
 248 {
 249         if (veth_is_xdp_frame(ptr))
 250                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 251         else
 252                 kfree_skb(ptr);
 253 }
 254
 255 static void __veth_xdp_flush(struct veth_rq *rq)
 256 {
 257         /* Write ptr_ring before reading rx_notify_masked */
 258         smp_mb();
 259         if (!READ_ONCE(rq->rx_notify_masked) &&
 260             napi_schedule_prep(&rq->xdp_napi)) {
 261                 WRITE_ONCE(rq->rx_notify_masked, true);
 262                 __napi_schedule(&rq->xdp_napi);
 263         }
 264 }
 265
 266 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 267 {
 268         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 269                 dev_kfree_skb_any(skb);
 270                 return NET_RX_DROP;
 271         }
 272
 273         return NET_RX_SUCCESS;
 274 }
 275
 276 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 277                             struct veth_rq *rq, bool xdp)
 278 {
 279         return __dev_forward_skb(dev, skb) ?: xdp ?
 280                 veth_xdp_rx(rq, skb) :
 281                 netif_rx(skb);
 282 }
 283
 284 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 285 {
 286         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 287         struct veth_rq *rq = NULL;
 288         struct net_device *rcv;
 289         int length = skb->len;
 290         bool rcv_xdp = false;
 291         int rxq;
 292
 293         rcu_read_lock();
 294         rcv = rcu_dereference(priv->peer);
 295         if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) {
 296                 kfree_skb(skb);
 297                 goto drop;
 298         }
 299
 300         rcv_priv = netdev_priv(rcv);
 301         rxq = skb_get_queue_mapping(skb);
 302         if (rxq < rcv->real_num_rx_queues) {
 303                 rq = &rcv_priv->rq[rxq];
 304                 rcv_xdp = rcu_access_pointer(rq->xdp_prog);
 305         }
 306
 307         skb_tx_timestamp(skb);
 308         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 309                 if (!rcv_xdp)
 310                         dev_lstats_add(dev, length);
 311         } else {
 312 drop:
 313                 atomic64_inc(&priv->dropped);
 314         }
 315
 316         if (rcv_xdp)
 317                 __veth_xdp_flush(rq);
 318
 319         rcu_read_unlock();
 320
 321         return NETDEV_TX_OK;
 322 }
 323
 324 static u64 veth_stats_tx(struct net_device *dev, u64 *packets, u64 *bytes)
 325 {
 326         struct veth_priv *priv = netdev_priv(dev);
 327
 328         dev_lstats_read(dev, packets, bytes);
 329         return atomic64_read(&priv->dropped);
 330 }
 331
 332 static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
 333 {
 334         struct veth_priv *priv = netdev_priv(dev);
 335         int i;
 336
 337         result->peer_tq_xdp_xmit_err = 0;
 338         result->xdp_packets = 0;
 339         result->xdp_tx_err = 0;
 340         result->xdp_bytes = 0;
 341         result->rx_drops = 0;
 342         for (i = 0; i < dev->num_rx_queues; i++) {
 343                 u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
 344                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 345                 unsigned int start;
 346
 347                 do {
 348                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 349                         peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
 350                         xdp_tx_err = stats->vs.xdp_tx_err;
 351                         packets = stats->vs.xdp_packets;
 352                         bytes = stats->vs.xdp_bytes;
 353                         drops = stats->vs.rx_drops;
 354                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 355                 result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
 356                 result->xdp_tx_err += xdp_tx_err;
 357                 result->xdp_packets += packets;
 358                 result->xdp_bytes += bytes;
 359                 result->rx_drops += drops;
 360         }
 361 }
 362
 363 static void veth_get_stats64(struct net_device *dev,
 364                              struct rtnl_link_stats64 *tot)
 365 {
 366         struct veth_priv *priv = netdev_priv(dev);
 367         struct net_device *peer;
 368         struct veth_stats rx;
 369         u64 packets, bytes;
 370
 371         tot->tx_dropped = veth_stats_tx(dev, &packets, &bytes);
 372         tot->tx_bytes = bytes;
 373         tot->tx_packets = packets;
 374
 375         veth_stats_rx(&rx, dev);
 376         tot->tx_dropped += rx.xdp_tx_err;
 377         tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
 378         tot->rx_bytes = rx.xdp_bytes;
 379         tot->rx_packets = rx.xdp_packets;
 380
 381         rcu_read_lock();
 382         peer = rcu_dereference(priv->peer);
 383         if (peer) {
 384                 veth_stats_tx(peer, &packets, &bytes);
 385                 tot->rx_bytes += bytes;
 386                 tot->rx_packets += packets;
 387
 388                 veth_stats_rx(&rx, peer);
 389                 tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
 390                 tot->rx_dropped += rx.xdp_tx_err;
 391                 tot->tx_bytes += rx.xdp_bytes;
 392                 tot->tx_packets += rx.xdp_packets;
 393         }
 394         rcu_read_unlock();
 395 }
 396
 397 /* fake multicast ability */
 398 static void veth_set_multicast_list(struct net_device *dev)
 399 {
 400 }
 401
 402 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 403                                       int buflen)
 404 {
 405         struct sk_buff *skb;
 406
 407         skb = build_skb(head, buflen);
 408         if (!skb)
 409                 return NULL;
 410
 411         skb_reserve(skb, headroom);
 412         skb_put(skb, len);
 413
 414         return skb;
 415 }
 416
 417 static int veth_select_rxq(struct net_device *dev)
 418 {
 419         return smp_processor_id() % dev->real_num_rx_queues;
 420 }
 421
 422 static struct net_device *veth_peer_dev(struct net_device *dev)
 423 {
 424         struct veth_priv *priv = netdev_priv(dev);
 425
 426         /* Callers must be under RCU read side. */
 427         return rcu_dereference(priv->peer);
 428 }
 429
 430 static int veth_xdp_xmit(struct net_device *dev, int n,
 431                          struct xdp_frame **frames,
 432                          u32 flags, bool ndo_xmit)
 433 {
 434         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 435         int i, ret = -ENXIO, drops = 0;
 436         struct net_device *rcv;
 437         unsigned int max_len;
 438         struct veth_rq *rq;
 439
 440         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
 441                 return -EINVAL;
 442
 443         rcu_read_lock();
 444         rcv = rcu_dereference(priv->peer);
 445         if (unlikely(!rcv))
 446                 goto out;
 447
 448         rcv_priv = netdev_priv(rcv);
 449         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 450         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 451          * side. This means an XDP program is loaded on the peer and the peer
 452          * device is up.
 453          */
 454         if (!rcu_access_pointer(rq->xdp_prog))
 455                 goto out;
 456
 457         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 458
 459         spin_lock(&rq->xdp_ring.producer_lock);
 460         for (i = 0; i < n; i++) {
 461                 struct xdp_frame *frame = frames[i];
 462                 void *ptr = veth_xdp_to_ptr(frame);
 463
 464                 if (unlikely(frame->len > max_len ||
 465                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 466                         xdp_return_frame_rx_napi(frame);
 467                         drops++;
 468                 }
 469         }
 470         spin_unlock(&rq->xdp_ring.producer_lock);
 471
 472         if (flags & XDP_XMIT_FLUSH)
 473                 __veth_xdp_flush(rq);
 474
 475         ret = n - drops;
 476         if (ndo_xmit) {
 477                 u64_stats_update_begin(&rq->stats.syncp);
 478                 rq->stats.vs.peer_tq_xdp_xmit += n - drops;
 479                 rq->stats.vs.peer_tq_xdp_xmit_err += drops;
 480                 u64_stats_update_end(&rq->stats.syncp);
 481         }
 482
 483 out:
 484         rcu_read_unlock();
 485
 486         return ret;
 487 }
 488
 489 static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
 490                              struct xdp_frame **frames, u32 flags)
 491 {
 492         int err;
 493
 494         err = veth_xdp_xmit(dev, n, frames, flags, true);
 495         if (err < 0) {
 496                 struct veth_priv *priv = netdev_priv(dev);
 497
 498                 atomic64_add(n, &priv->dropped);
 499         }
 500
 501         return err;
 502 }
 503
 504 static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
 505 {
 506         int sent, i, err = 0;
 507
 508         sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
 509         if (sent < 0) {
 510                 err = sent;
 511                 sent = 0;
 512                 for (i = 0; i < bq->count; i++)
 513                         xdp_return_frame(bq->q[i]);
 514         }
 515         trace_xdp_bulk_tx(rq->dev, sent, bq->count - sent, err);
 516
 517         u64_stats_update_begin(&rq->stats.syncp);
 518         rq->stats.vs.xdp_tx += sent;
 519         rq->stats.vs.xdp_tx_err += bq->count - sent;
 520         u64_stats_update_end(&rq->stats.syncp);
 521
 522         bq->count = 0;
 523 }
 524
 525 static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
 526 {
 527         struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
 528         struct net_device *rcv;
 529         struct veth_rq *rcv_rq;
 530
 531         rcu_read_lock();
 532         veth_xdp_flush_bq(rq, bq);
 533         rcv = rcu_dereference(priv->peer);
 534         if (unlikely(!rcv))
 535                 goto out;
 536
 537         rcv_priv = netdev_priv(rcv);
 538         rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 539         /* xdp_ring is initialized on receive side? */
 540         if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
 541                 goto out;
 542
 543         __veth_xdp_flush(rcv_rq);
 544 out:
 545         rcu_read_unlock();
 546 }
 547
 548 static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
 549                        struct veth_xdp_tx_bq *bq)
 550 {
 551         struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
 552
 553         if (unlikely(!frame))
 554                 return -EOVERFLOW;
 555
 556         if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
 557                 veth_xdp_flush_bq(rq, bq);
 558
 559         bq->q[bq->count++] = frame;
 560
 561         return 0;
 562 }
 563
 564 static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 565                                         struct xdp_frame *frame,
 566                                         struct veth_xdp_tx_bq *bq,
 567                                         struct veth_stats *stats)
 568 {
 569         void *hard_start = frame->data - frame->headroom;
 570         int len = frame->len, delta = 0;
 571         struct xdp_frame orig_frame;
 572         struct bpf_prog *xdp_prog;
 573         unsigned int headroom;
 574         struct sk_buff *skb;
 575
 576         /* bpf_xdp_adjust_head() assures BPF cannot access xdp_frame area */
 577         hard_start -= sizeof(struct xdp_frame);
 578
 579         rcu_read_lock();
 580         xdp_prog = rcu_dereference(rq->xdp_prog);
 581         if (likely(xdp_prog)) {
 582                 struct xdp_buff xdp;
 583                 u32 act;
 584
 585                 xdp_convert_frame_to_buff(frame, &xdp);
 586                 xdp.rxq = &rq->xdp_rxq;
 587
 588                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 589
 590                 switch (act) {
 591                 case XDP_PASS:
 592                         delta = frame->data - xdp.data;
 593                         len = xdp.data_end - xdp.data;
 594                         break;
 595                 case XDP_TX:
 596                         orig_frame = *frame;
 597                         xdp.rxq->mem = frame->mem;
 598                         if (unlikely(veth_xdp_tx(rq, &xdp, bq) < 0)) {
 599                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 600                                 frame = &orig_frame;
 601                                 stats->rx_drops++;
 602                                 goto err_xdp;
 603                         }
 604                         stats->xdp_tx++;
 605                         rcu_read_unlock();
 606                         goto xdp_xmit;
 607                 case XDP_REDIRECT:
 608                         orig_frame = *frame;
 609                         xdp.rxq->mem = frame->mem;
 610                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 611                                 frame = &orig_frame;
 612                                 stats->rx_drops++;
 613                                 goto err_xdp;
 614                         }
 615                         stats->xdp_redirect++;
 616                         rcu_read_unlock();
 617                         goto xdp_xmit;
 618                 default:
 619                         bpf_warn_invalid_xdp_action(act);
 620                         fallthrough;
 621                 case XDP_ABORTED:
 622                         trace_xdp_exception(rq->dev, xdp_prog, act);
 623                         fallthrough;
 624                 case XDP_DROP:
 625                         stats->xdp_drops++;
 626                         goto err_xdp;
 627                 }
 628         }
 629         rcu_read_unlock();
 630
 631         headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
 632         skb = veth_build_skb(hard_start, headroom, len, frame->frame_sz);
 633         if (!skb) {
 634                 xdp_return_frame(frame);
 635                 stats->rx_drops++;
 636                 goto err;
 637         }
 638
 639         xdp_release_frame(frame);
 640         xdp_scrub_frame(frame);
 641         skb->protocol = eth_type_trans(skb, rq->dev);
 642 err:
 643         return skb;
 644 err_xdp:
 645         rcu_read_unlock();
 646         xdp_return_frame(frame);
 647 xdp_xmit:
 648         return NULL;
 649 }
 650
 651 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
 652                                         struct sk_buff *skb,
 653                                         struct veth_xdp_tx_bq *bq,
 654                                         struct veth_stats *stats)
 655 {
 656         u32 pktlen, headroom, act, metalen;
 657         void *orig_data, *orig_data_end;
 658         struct bpf_prog *xdp_prog;
 659         int mac_len, delta, off;
 660         struct xdp_buff xdp;
 661
 662         skb_orphan(skb);
 663
 664         rcu_read_lock();
 665         xdp_prog = rcu_dereference(rq->xdp_prog);
 666         if (unlikely(!xdp_prog)) {
 667                 rcu_read_unlock();
 668                 goto out;
 669         }
 670
 671         mac_len = skb->data - skb_mac_header(skb);
 672         pktlen = skb->len + mac_len;
 673         headroom = skb_headroom(skb) - mac_len;
 674
 675         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 676             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 677                 struct sk_buff *nskb;
 678                 int size, head_off;
 679                 void *head, *start;
 680                 struct page *page;
 681
 682                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 683                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 684                 if (size > PAGE_SIZE)
 685                         goto drop;
 686
 687                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 688                 if (!page)
 689                         goto drop;
 690
 691                 head = page_address(page);
 692                 start = head + VETH_XDP_HEADROOM;
 693                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 694                         page_frag_free(head);
 695                         goto drop;
 696                 }
 697
 698                 nskb = veth_build_skb(head, VETH_XDP_HEADROOM + mac_len,
 699                                       skb->len, PAGE_SIZE);
 700                 if (!nskb) {
 701                         page_frag_free(head);
 702                         goto drop;
 703                 }
 704
 705                 skb_copy_header(nskb, skb);
 706                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 707                 skb_headers_offset_update(nskb, head_off);
 708                 consume_skb(skb);
 709                 skb = nskb;
 710         }
 711
 712         xdp.data_hard_start = skb->head;
 713         xdp.data = skb_mac_header(skb);
 714         xdp.data_end = xdp.data + pktlen;
 715         xdp.data_meta = xdp.data;
 716         xdp.rxq = &rq->xdp_rxq;
 717
 718         /* SKB "head" area always have tailroom for skb_shared_info */
 719         xdp.frame_sz = (void *)skb_end_pointer(skb) - xdp.data_hard_start;
 720         xdp.frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 721
 722         orig_data = xdp.data;
 723         orig_data_end = xdp.data_end;
 724
 725         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 726
 727         switch (act) {
 728         case XDP_PASS:
 729                 break;
 730         case XDP_TX:
 731                 get_page(virt_to_page(xdp.data));
 732                 consume_skb(skb);
 733                 xdp.rxq->mem = rq->xdp_mem;
 734                 if (unlikely(veth_xdp_tx(rq, &xdp, bq) < 0)) {
 735                         trace_xdp_exception(rq->dev, xdp_prog, act);
 736                         stats->rx_drops++;
 737                         goto err_xdp;
 738                 }
 739                 stats->xdp_tx++;
 740                 rcu_read_unlock();
 741                 goto xdp_xmit;
 742         case XDP_REDIRECT:
 743                 get_page(virt_to_page(xdp.data));
 744                 consume_skb(skb);
 745                 xdp.rxq->mem = rq->xdp_mem;
 746                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 747                         stats->rx_drops++;
 748                         goto err_xdp;
 749                 }
 750                 stats->xdp_redirect++;
 751                 rcu_read_unlock();
 752                 goto xdp_xmit;
 753         default:
 754                 bpf_warn_invalid_xdp_action(act);
 755                 fallthrough;
 756         case XDP_ABORTED:
 757                 trace_xdp_exception(rq->dev, xdp_prog, act);
 758                 fallthrough;
 759         case XDP_DROP:
 760                 stats->xdp_drops++;
 761                 goto xdp_drop;
 762         }
 763         rcu_read_unlock();
 764
 765         /* check if bpf_xdp_adjust_head was used */
 766         delta = orig_data - xdp.data;
 767         off = mac_len + delta;
 768         if (off > 0)
 769                 __skb_push(skb, off);
 770         else if (off < 0)
 771                 __skb_pull(skb, -off);
 772         skb->mac_header -= delta;
 773
 774         /* check if bpf_xdp_adjust_tail was used */
 775         off = xdp.data_end - orig_data_end;
 776         if (off != 0)
 777                 __skb_put(skb, off); /* positive on grow, negative on shrink */
 778         skb->protocol = eth_type_trans(skb, rq->dev);
 779
 780         metalen = xdp.data - xdp.data_meta;
 781         if (metalen)
 782                 skb_metadata_set(skb, metalen);
 783 out:
 784         return skb;
 785 drop:
 786         stats->rx_drops++;
 787 xdp_drop:
 788         rcu_read_unlock();
 789         kfree_skb(skb);
 790         return NULL;
 791 err_xdp:
 792         rcu_read_unlock();
 793         page_frag_free(xdp.data);
 794 xdp_xmit:
 795         return NULL;
 796 }
 797
 798 static int veth_xdp_rcv(struct veth_rq *rq, int budget,
 799                         struct veth_xdp_tx_bq *bq,
 800                         struct veth_stats *stats)
 801 {
 802         int i, done = 0;
 803
 804         for (i = 0; i < budget; i++) {
 805                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 806                 struct sk_buff *skb;
 807
 808                 if (!ptr)
 809                         break;
 810
 811                 if (veth_is_xdp_frame(ptr)) {
 812                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 813
 814                         stats->xdp_bytes += frame->len;
 815                         skb = veth_xdp_rcv_one(rq, frame, bq, stats);
 816                 } else {
 817                         skb = ptr;
 818                         stats->xdp_bytes += skb->len;
 819                         skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
 820                 }
 821
 822                 if (skb)
 823                         napi_gro_receive(&rq->xdp_napi, skb);
 824
 825                 done++;
 826         }
 827
 828         u64_stats_update_begin(&rq->stats.syncp);
 829         rq->stats.vs.xdp_redirect += stats->xdp_redirect;
 830         rq->stats.vs.xdp_bytes += stats->xdp_bytes;
 831         rq->stats.vs.xdp_drops += stats->xdp_drops;
 832         rq->stats.vs.rx_drops += stats->rx_drops;
 833         rq->stats.vs.xdp_packets += done;
 834         u64_stats_update_end(&rq->stats.syncp);
 835
 836         return done;
 837 }
 838
 839 static int veth_poll(struct napi_struct *napi, int budget)
 840 {
 841         struct veth_rq *rq =
 842                 container_of(napi, struct veth_rq, xdp_napi);
 843         struct veth_stats stats = {};
 844         struct veth_xdp_tx_bq bq;
 845         int done;
 846
 847         bq.count = 0;
 848
 849         xdp_set_return_frame_no_direct();
 850         done = veth_xdp_rcv(rq, budget, &bq, &stats);
 851
 852         if (done < budget && napi_complete_done(napi, done)) {
 853                 /* Write rx_notify_masked before reading ptr_ring */
 854                 smp_store_mb(rq->rx_notify_masked, false);
 855                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 856                         if (napi_schedule_prep(&rq->xdp_napi)) {
 857                                 WRITE_ONCE(rq->rx_notify_masked, true);
 858                                 __napi_schedule(&rq->xdp_napi);
 859                         }
 860                 }
 861         }
 862
 863         if (stats.xdp_tx > 0)
 864                 veth_xdp_flush(rq, &bq);
 865         if (stats.xdp_redirect > 0)
 866                 xdp_do_flush();
 867         xdp_clear_return_frame_no_direct();
 868
 869         return done;
 870 }
 871
 872 static int veth_napi_add(struct net_device *dev)
 873 {
 874         struct veth_priv *priv = netdev_priv(dev);
 875         int err, i;
 876
 877         for (i = 0; i < dev->real_num_rx_queues; i++) {
 878                 struct veth_rq *rq = &priv->rq[i];
 879
 880                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 881                 if (err)
 882                         goto err_xdp_ring;
 883         }
 884
 885         for (i = 0; i < dev->real_num_rx_queues; i++) {
 886                 struct veth_rq *rq = &priv->rq[i];
 887
 888                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 889                 napi_enable(&rq->xdp_napi);
 890         }
 891
 892         return 0;
 893 err_xdp_ring:
 894         for (i--; i >= 0; i--)
 895                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 896
 897         return err;
 898 }
 899
 900 static void veth_napi_del(struct net_device *dev)
 901 {
 902         struct veth_priv *priv = netdev_priv(dev);
 903         int i;
 904
 905         for (i = 0; i < dev->real_num_rx_queues; i++) {
 906                 struct veth_rq *rq = &priv->rq[i];
 907
 908                 napi_disable(&rq->xdp_napi);
 909                 __netif_napi_del(&rq->xdp_napi);
 910         }
 911         synchronize_net();
 912
 913         for (i = 0; i < dev->real_num_rx_queues; i++) {
 914                 struct veth_rq *rq = &priv->rq[i];
 915
 916                 rq->rx_notify_masked = false;
 917                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 918         }
 919 }
 920
 921 static int veth_enable_xdp(struct net_device *dev)
 922 {
 923         struct veth_priv *priv = netdev_priv(dev);
 924         int err, i;
 925
 926         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 927                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 928                         struct veth_rq *rq = &priv->rq[i];
 929
 930                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i);
 931                         if (err < 0)
 932                                 goto err_rxq_reg;
 933
 934                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 935                                                          MEM_TYPE_PAGE_SHARED,
 936                                                          NULL);
 937                         if (err < 0)
 938                                 goto err_reg_mem;
 939
 940                         /* Save original mem info as it can be overwritten */
 941                         rq->xdp_mem = rq->xdp_rxq.mem;
 942                 }
 943
 944                 err = veth_napi_add(dev);
 945                 if (err)
 946                         goto err_rxq_reg;
 947         }
 948
 949         for (i = 0; i < dev->real_num_rx_queues; i++)
 950                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 951
 952         return 0;
 953 err_reg_mem:
 954         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 955 err_rxq_reg:
 956         for (i--; i >= 0; i--)
 957                 xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 958
 959         return err;
 960 }
 961
 962 static void veth_disable_xdp(struct net_device *dev)
 963 {
 964         struct veth_priv *priv = netdev_priv(dev);
 965         int i;
 966
 967         for (i = 0; i < dev->real_num_rx_queues; i++)
 968                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 969         veth_napi_del(dev);
 970         for (i = 0; i < dev->real_num_rx_queues; i++) {
 971                 struct veth_rq *rq = &priv->rq[i];
 972
 973                 rq->xdp_rxq.mem = rq->xdp_mem;
 974                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 975         }
 976 }
 977
 978 static int veth_open(struct net_device *dev)
 979 {
 980         struct veth_priv *priv = netdev_priv(dev);
 981         struct net_device *peer = rtnl_dereference(priv->peer);
 982         int err;
 983
 984         if (!peer)
 985                 return -ENOTCONN;
 986
 987         if (priv->_xdp_prog) {
 988                 err = veth_enable_xdp(dev);
 989                 if (err)
 990                         return err;
 991         }
 992
 993         if (peer->flags & IFF_UP) {
 994                 netif_carrier_on(dev);
 995                 netif_carrier_on(peer);
 996         }
 997
 998         return 0;
 999 }
1000
1001 static int veth_close(struct net_device *dev)
1002 {
1003         struct veth_priv *priv = netdev_priv(dev);
1004         struct net_device *peer = rtnl_dereference(priv->peer);
1005
1006         netif_carrier_off(dev);
1007         if (peer)
1008                 netif_carrier_off(peer);
1009
1010         if (priv->_xdp_prog)
1011                 veth_disable_xdp(dev);
1012
1013         return 0;
1014 }
1015
1016 static int is_valid_veth_mtu(int mtu)
1017 {
1018         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
1019 }
1020
1021 static int veth_alloc_queues(struct net_device *dev)
1022 {
1023         struct veth_priv *priv = netdev_priv(dev);
1024         int i;
1025
1026         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
1027         if (!priv->rq)
1028                 return -ENOMEM;
1029
1030         for (i = 0; i < dev->num_rx_queues; i++) {
1031                 priv->rq[i].dev = dev;
1032                 u64_stats_init(&priv->rq[i].stats.syncp);
1033         }
1034
1035         return 0;
1036 }
1037
1038 static void veth_free_queues(struct net_device *dev)
1039 {
1040         struct veth_priv *priv = netdev_priv(dev);
1041
1042         kfree(priv->rq);
1043 }
1044
1045 static int veth_dev_init(struct net_device *dev)
1046 {
1047         int err;
1048
1049         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
1050         if (!dev->lstats)
1051                 return -ENOMEM;
1052
1053         err = veth_alloc_queues(dev);
1054         if (err) {
1055                 free_percpu(dev->lstats);
1056                 return err;
1057         }
1058
1059         return 0;
1060 }
1061
1062 static void veth_dev_free(struct net_device *dev)
1063 {
1064         veth_free_queues(dev);
1065         free_percpu(dev->lstats);
1066 }
1067
1068 #ifdef CONFIG_NET_POLL_CONTROLLER
1069 static void veth_poll_controller(struct net_device *dev)
1070 {
1071         /* veth only receives frames when its peer sends one
1072          * Since it has nothing to do with disabling irqs, we are guaranteed
1073          * never to have pending data when we poll for it so
1074          * there is nothing to do here.
1075          *
1076          * We need this though so netpoll recognizes us as an interface that
1077          * supports polling, which enables bridge devices in virt setups to
1078          * still use netconsole
1079          */
1080 }
1081 #endif  /* CONFIG_NET_POLL_CONTROLLER */
1082
1083 static int veth_get_iflink(const struct net_device *dev)
1084 {
1085         struct veth_priv *priv = netdev_priv(dev);
1086         struct net_device *peer;
1087         int iflink;
1088
1089         rcu_read_lock();
1090         peer = rcu_dereference(priv->peer);
1091         iflink = peer ? peer->ifindex : 0;
1092         rcu_read_unlock();
1093
1094         return iflink;
1095 }
1096
1097 static netdev_features_t veth_fix_features(struct net_device *dev,
1098                                            netdev_features_t features)
1099 {
1100         struct veth_priv *priv = netdev_priv(dev);
1101         struct net_device *peer;
1102
1103         peer = rtnl_dereference(priv->peer);
1104         if (peer) {
1105                 struct veth_priv *peer_priv = netdev_priv(peer);
1106
1107                 if (peer_priv->_xdp_prog)
1108                         features &= ~NETIF_F_GSO_SOFTWARE;
1109         }
1110
1111         return features;
1112 }
1113
1114 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1115 {
1116         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1117         struct net_device *peer;
1118
1119         if (new_hr < 0)
1120                 new_hr = 0;
1121
1122         rcu_read_lock();
1123         peer = rcu_dereference(priv->peer);
1124         if (unlikely(!peer))
1125                 goto out;
1126
1127         peer_priv = netdev_priv(peer);
1128         priv->requested_headroom = new_hr;
1129         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1130         dev->needed_headroom = new_hr;
1131         peer->needed_headroom = new_hr;
1132
1133 out:
1134         rcu_read_unlock();
1135 }
1136
1137 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1138                         struct netlink_ext_ack *extack)
1139 {
1140         struct veth_priv *priv = netdev_priv(dev);
1141         struct bpf_prog *old_prog;
1142         struct net_device *peer;
1143         unsigned int max_mtu;
1144         int err;
1145
1146         old_prog = priv->_xdp_prog;
1147         priv->_xdp_prog = prog;
1148         peer = rtnl_dereference(priv->peer);
1149
1150         if (prog) {
1151                 if (!peer) {
1152                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1153                         err = -ENOTCONN;
1154                         goto err;
1155                 }
1156
1157                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
1158                           peer->hard_header_len -
1159                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1160                 if (peer->mtu > max_mtu) {
1161                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1162                         err = -ERANGE;
1163                         goto err;
1164                 }
1165
1166                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1167                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1168                         err = -ENOSPC;
1169                         goto err;
1170                 }
1171
1172                 if (dev->flags & IFF_UP) {
1173                         err = veth_enable_xdp(dev);
1174                         if (err) {
1175                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1176                                 goto err;
1177                         }
1178                 }
1179
1180                 if (!old_prog) {
1181                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1182                         peer->max_mtu = max_mtu;
1183                 }
1184         }
1185
1186         if (old_prog) {
1187                 if (!prog) {
1188                         if (dev->flags & IFF_UP)
1189                                 veth_disable_xdp(dev);
1190
1191                         if (peer) {
1192                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1193                                 peer->max_mtu = ETH_MAX_MTU;
1194                         }
1195                 }
1196                 bpf_prog_put(old_prog);
1197         }
1198
1199         if ((!!old_prog ^ !!prog) && peer)
1200                 netdev_update_features(peer);
1201
1202         return 0;
1203 err:
1204         priv->_xdp_prog = old_prog;
1205
1206         return err;
1207 }
1208
1209 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1210 {
1211         switch (xdp->command) {
1212         case XDP_SETUP_PROG:
1213                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1214         default:
1215                 return -EINVAL;
1216         }
1217 }
1218
1219 static const struct net_device_ops veth_netdev_ops = {
1220         .ndo_init            = veth_dev_init,
1221         .ndo_open            = veth_open,
1222         .ndo_stop            = veth_close,
1223         .ndo_start_xmit      = veth_xmit,
1224         .ndo_get_stats64     = veth_get_stats64,
1225         .ndo_set_rx_mode     = veth_set_multicast_list,
1226         .ndo_set_mac_address = eth_mac_addr,
1227 #ifdef CONFIG_NET_POLL_CONTROLLER
1228         .ndo_poll_controller    = veth_poll_controller,
1229 #endif
1230         .ndo_get_iflink         = veth_get_iflink,
1231         .ndo_fix_features       = veth_fix_features,
1232         .ndo_features_check     = passthru_features_check,
1233         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1234         .ndo_bpf                = veth_xdp,
1235         .ndo_xdp_xmit           = veth_ndo_xdp_xmit,
1236         .ndo_get_peer_dev       = veth_peer_dev,
1237 };
1238
1239 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1240                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1241                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1242                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1243                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1244
1245 static void veth_setup(struct net_device *dev)
1246 {
1247         ether_setup(dev);
1248
1249         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1250         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1251         dev->priv_flags |= IFF_NO_QUEUE;
1252         dev->priv_flags |= IFF_PHONY_HEADROOM;
1253
1254         dev->netdev_ops = &veth_netdev_ops;
1255         dev->ethtool_ops = &veth_ethtool_ops;
1256         dev->features |= NETIF_F_LLTX;
1257         dev->features |= VETH_FEATURES;
1258         dev->vlan_features = dev->features &
1259                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1260                                NETIF_F_HW_VLAN_STAG_TX |
1261                                NETIF_F_HW_VLAN_CTAG_RX |
1262                                NETIF_F_HW_VLAN_STAG_RX);
1263         dev->needs_free_netdev = true;
1264         dev->priv_destructor = veth_dev_free;
1265         dev->max_mtu = ETH_MAX_MTU;
1266
1267         dev->hw_features = VETH_FEATURES;
1268         dev->hw_enc_features = VETH_FEATURES;
1269         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1270 }
1271
1272 /*
1273  * netlink interface
1274  */
1275
1276 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1277                          struct netlink_ext_ack *extack)
1278 {
1279         if (tb[IFLA_ADDRESS]) {
1280                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1281                         return -EINVAL;
1282                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1283                         return -EADDRNOTAVAIL;
1284         }
1285         if (tb[IFLA_MTU]) {
1286                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1287                         return -EINVAL;
1288         }
1289         return 0;
1290 }
1291
1292 static struct rtnl_link_ops veth_link_ops;
1293
1294 static int veth_newlink(struct net *src_net, struct net_device *dev,
1295                         struct nlattr *tb[], struct nlattr *data[],
1296                         struct netlink_ext_ack *extack)
1297 {
1298         int err;
1299         struct net_device *peer;
1300         struct veth_priv *priv;
1301         char ifname[IFNAMSIZ];
1302         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1303         unsigned char name_assign_type;
1304         struct ifinfomsg *ifmp;
1305         struct net *net;
1306
1307         /*
1308          * create and register peer first
1309          */
1310         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1311                 struct nlattr *nla_peer;
1312
1313                 nla_peer = data[VETH_INFO_PEER];
1314                 ifmp = nla_data(nla_peer);
1315                 err = rtnl_nla_parse_ifla(peer_tb,
1316                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1317                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1318                                           NULL);
1319                 if (err < 0)
1320                         return err;
1321
1322                 err = veth_validate(peer_tb, NULL, extack);
1323                 if (err < 0)
1324                         return err;
1325
1326                 tbp = peer_tb;
1327         } else {
1328                 ifmp = NULL;
1329                 tbp = tb;
1330         }
1331
1332         if (ifmp && tbp[IFLA_IFNAME]) {
1333                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1334                 name_assign_type = NET_NAME_USER;
1335         } else {
1336                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1337                 name_assign_type = NET_NAME_ENUM;
1338         }
1339
1340         net = rtnl_link_get_net(src_net, tbp);
1341         if (IS_ERR(net))
1342                 return PTR_ERR(net);
1343
1344         peer = rtnl_create_link(net, ifname, name_assign_type,
1345                                 &veth_link_ops, tbp, extack);
1346         if (IS_ERR(peer)) {
1347                 put_net(net);
1348                 return PTR_ERR(peer);
1349         }
1350
1351         if (!ifmp || !tbp[IFLA_ADDRESS])
1352                 eth_hw_addr_random(peer);
1353
1354         if (ifmp && (dev->ifindex != 0))
1355                 peer->ifindex = ifmp->ifi_index;
1356
1357         peer->gso_max_size = dev->gso_max_size;
1358         peer->gso_max_segs = dev->gso_max_segs;
1359
1360         err = register_netdevice(peer);
1361         put_net(net);
1362         net = NULL;
1363         if (err < 0)
1364                 goto err_register_peer;
1365
1366         netif_carrier_off(peer);
1367
1368         err = rtnl_configure_link(peer, ifmp);
1369         if (err < 0)
1370                 goto err_configure_peer;
1371
1372         /*
1373          * register dev last
1374          *
1375          * note, that since we've registered new device the dev's name
1376          * should be re-allocated
1377          */
1378
1379         if (tb[IFLA_ADDRESS] == NULL)
1380                 eth_hw_addr_random(dev);
1381
1382         if (tb[IFLA_IFNAME])
1383                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1384         else
1385                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1386
1387         err = register_netdevice(dev);
1388         if (err < 0)
1389                 goto err_register_dev;
1390
1391         netif_carrier_off(dev);
1392
1393         /*
1394          * tie the deviced together
1395          */
1396
1397         priv = netdev_priv(dev);
1398         rcu_assign_pointer(priv->peer, peer);
1399
1400         priv = netdev_priv(peer);
1401         rcu_assign_pointer(priv->peer, dev);
1402
1403         return 0;
1404
1405 err_register_dev:
1406         /* nothing to do */
1407 err_configure_peer:
1408         unregister_netdevice(peer);
1409         return err;
1410
1411 err_register_peer:
1412         free_netdev(peer);
1413         return err;
1414 }
1415
1416 static void veth_dellink(struct net_device *dev, struct list_head *head)
1417 {
1418         struct veth_priv *priv;
1419         struct net_device *peer;
1420
1421         priv = netdev_priv(dev);
1422         peer = rtnl_dereference(priv->peer);
1423
1424         /* Note : dellink() is called from default_device_exit_batch(),
1425          * before a rcu_synchronize() point. The devices are guaranteed
1426          * not being freed before one RCU grace period.
1427          */
1428         RCU_INIT_POINTER(priv->peer, NULL);
1429         unregister_netdevice_queue(dev, head);
1430
1431         if (peer) {
1432                 priv = netdev_priv(peer);
1433                 RCU_INIT_POINTER(priv->peer, NULL);
1434                 unregister_netdevice_queue(peer, head);
1435         }
1436 }
1437
1438 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1439         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1440 };
1441
1442 static struct net *veth_get_link_net(const struct net_device *dev)
1443 {
1444         struct veth_priv *priv = netdev_priv(dev);
1445         struct net_device *peer = rtnl_dereference(priv->peer);
1446
1447         return peer ? dev_net(peer) : dev_net(dev);
1448 }
1449
1450 static struct rtnl_link_ops veth_link_ops = {
1451         .kind           = DRV_NAME,
1452         .priv_size      = sizeof(struct veth_priv),
1453         .setup          = veth_setup,
1454         .validate       = veth_validate,
1455         .newlink        = veth_newlink,
1456         .dellink        = veth_dellink,
1457         .policy         = veth_policy,
1458         .maxtype        = VETH_INFO_MAX,
1459         .get_link_net   = veth_get_link_net,
1460 };
1461
1462 /*
1463  * init/fini
1464  */
1465
1466 static __init int veth_init(void)
1467 {
1468         return rtnl_link_register(&veth_link_ops);
1469 }
1470
1471 static __exit void veth_exit(void)
1472 {
1473         rtnl_link_unregister(&veth_link_ops);
1474 }
1475
1476 module_init(veth_init);
1477 module_exit(veth_exit);
1478
1479 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1480 MODULE_LICENSE("GPL v2");
1481 MODULE_ALIAS_RTNL_LINK(DRV_NAME);