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 #define VETH_XDP_BATCH          16
  39
  40 struct veth_stats {
  41         u64     rx_drops;
  42         /* xdp */
  43         u64     xdp_packets;
  44         u64     xdp_bytes;
  45         u64     xdp_redirect;
  46         u64     xdp_drops;
  47         u64     xdp_tx;
  48         u64     xdp_tx_err;
  49         u64     peer_tq_xdp_xmit;
  50         u64     peer_tq_xdp_xmit_err;
  51 };
  52
  53 struct veth_rq_stats {
  54         struct veth_stats       vs;
  55         struct u64_stats_sync   syncp;
  56 };
  57
  58 struct veth_rq {
  59         struct napi_struct      xdp_napi;
  60         struct net_device       *dev;
  61         struct bpf_prog __rcu   *xdp_prog;
  62         struct xdp_mem_info     xdp_mem;
  63         struct veth_rq_stats    stats;
  64         bool                    rx_notify_masked;
  65         struct ptr_ring         xdp_ring;
  66         struct xdp_rxq_info     xdp_rxq;
  67 };
  68
  69 struct veth_priv {
  70         struct net_device __rcu *peer;
  71         atomic64_t              dropped;
  72         struct bpf_prog         *_xdp_prog;
  73         struct veth_rq          *rq;
  74         unsigned int            requested_headroom;
  75 };
  76
  77 struct veth_xdp_tx_bq {
  78         struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
  79         unsigned int count;
  80 };
  81
  82 /*
  83  * ethtool interface
  84  */
  85
  86 struct veth_q_stat_desc {
  87         char    desc[ETH_GSTRING_LEN];
  88         size_t  offset;
  89 };
  90
  91 #define VETH_RQ_STAT(m) offsetof(struct veth_stats, m)
  92
  93 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  94         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  95         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  96         { "drops",              VETH_RQ_STAT(rx_drops) },
  97         { "xdp_redirect",       VETH_RQ_STAT(xdp_redirect) },
  98         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
  99         { "xdp_tx",             VETH_RQ_STAT(xdp_tx) },
 100         { "xdp_tx_errors",      VETH_RQ_STAT(xdp_tx_err) },
 101 };
 102
 103 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
 104
 105 static const struct veth_q_stat_desc veth_tq_stats_desc[] = {
 106         { "xdp_xmit",           VETH_RQ_STAT(peer_tq_xdp_xmit) },
 107         { "xdp_xmit_errors",    VETH_RQ_STAT(peer_tq_xdp_xmit_err) },
 108 };
 109
 110 #define VETH_TQ_STATS_LEN       ARRAY_SIZE(veth_tq_stats_desc)
 111
 112 static struct {
 113         const char string[ETH_GSTRING_LEN];
 114 } ethtool_stats_keys[] = {
 115         { "peer_ifindex" },
 116 };
 117
 118 static int veth_get_link_ksettings(struct net_device *dev,
 119                                    struct ethtool_link_ksettings *cmd)
 120 {
 121         cmd->base.speed         = SPEED_10000;
 122         cmd->base.duplex        = DUPLEX_FULL;
 123         cmd->base.port          = PORT_TP;
 124         cmd->base.autoneg       = AUTONEG_DISABLE;
 125         return 0;
 126 }
 127
 128 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 129 {
 130         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 131         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 132 }
 133
 134 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 135 {
 136         char *p = (char *)buf;
 137         int i, j;
 138
 139         switch(stringset) {
 140         case ETH_SS_STATS:
 141                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 142                 p += sizeof(ethtool_stats_keys);
 143                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 144                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 145                                 snprintf(p, ETH_GSTRING_LEN,
 146                                          "rx_queue_%u_%.18s",
 147                                          i, veth_rq_stats_desc[j].desc);
 148                                 p += ETH_GSTRING_LEN;
 149                         }
 150                 }
 151                 for (i = 0; i < dev->real_num_tx_queues; i++) {
 152                         for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
 153                                 snprintf(p, ETH_GSTRING_LEN,
 154                                          "tx_queue_%u_%.18s",
 155                                          i, veth_tq_stats_desc[j].desc);
 156                                 p += ETH_GSTRING_LEN;
 157                         }
 158                 }
 159                 break;
 160         }
 161 }
 162
 163 static int veth_get_sset_count(struct net_device *dev, int sset)
 164 {
 165         switch (sset) {
 166         case ETH_SS_STATS:
 167                 return ARRAY_SIZE(ethtool_stats_keys) +
 168                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues +
 169                        VETH_TQ_STATS_LEN * dev->real_num_tx_queues;
 170         default:
 171                 return -EOPNOTSUPP;
 172         }
 173 }
 174
 175 static void veth_get_ethtool_stats(struct net_device *dev,
 176                 struct ethtool_stats *stats, u64 *data)
 177 {
 178         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 179         struct net_device *peer = rtnl_dereference(priv->peer);
 180         int i, j, idx;
 181
 182         data[0] = peer ? peer->ifindex : 0;
 183         idx = 1;
 184         for (i = 0; i < dev->real_num_rx_queues; i++) {
 185                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 186                 const void *stats_base = (void *)&rq_stats->vs;
 187                 unsigned int start;
 188                 size_t offset;
 189
 190                 do {
 191                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 192                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 193                                 offset = veth_rq_stats_desc[j].offset;
 194                                 data[idx + j] = *(u64 *)(stats_base + offset);
 195                         }
 196                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 197                 idx += VETH_RQ_STATS_LEN;
 198         }
 199
 200         if (!peer)
 201                 return;
 202
 203         rcv_priv = netdev_priv(peer);
 204         for (i = 0; i < peer->real_num_rx_queues; i++) {
 205                 const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
 206                 const void *base = (void *)&rq_stats->vs;
 207                 unsigned int start, tx_idx = idx;
 208                 size_t offset;
 209
 210                 tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
 211                 do {
 212                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 213                         for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
 214                                 offset = veth_tq_stats_desc[j].offset;
 215                                 data[tx_idx + j] += *(u64 *)(base + offset);
 216                         }
 217                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 218         }
 219 }
 220
 221 static const struct ethtool_ops veth_ethtool_ops = {
 222         .get_drvinfo            = veth_get_drvinfo,
 223         .get_link               = ethtool_op_get_link,
 224         .get_strings            = veth_get_strings,
 225         .get_sset_count         = veth_get_sset_count,
 226         .get_ethtool_stats      = veth_get_ethtool_stats,
 227         .get_link_ksettings     = veth_get_link_ksettings,
 228         .get_ts_info            = ethtool_op_get_ts_info,
 229 };
 230
 231 /* general routines */
 232
 233 static bool veth_is_xdp_frame(void *ptr)
 234 {
 235         return (unsigned long)ptr & VETH_XDP_FLAG;
 236 }
 237
 238 static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
 239 {
 240         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 241 }
 242
 243 static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
 244 {
 245         return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
 246 }
 247
 248 static void veth_ptr_free(void *ptr)
 249 {
 250         if (veth_is_xdp_frame(ptr))
 251                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 252         else
 253                 kfree_skb(ptr);
 254 }
 255
 256 static void __veth_xdp_flush(struct veth_rq *rq)
 257 {
 258         /* Write ptr_ring before reading rx_notify_masked */
 259         smp_mb();
 260         if (!rq->rx_notify_masked) {
 261                 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)) {
 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                 if (rcv_xdp)
 306                         skb_record_rx_queue(skb, rxq);
 307         }
 308
 309         skb_tx_timestamp(skb);
 310         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 311                 if (!rcv_xdp)
 312                         dev_lstats_add(dev, length);
 313         } else {
 314 drop:
 315                 atomic64_inc(&priv->dropped);
 316         }
 317
 318         if (rcv_xdp)
 319                 __veth_xdp_flush(rq);
 320
 321         rcu_read_unlock();
 322
 323         return NETDEV_TX_OK;
 324 }
 325
 326 static u64 veth_stats_tx(struct net_device *dev, u64 *packets, u64 *bytes)
 327 {
 328         struct veth_priv *priv = netdev_priv(dev);
 329
 330         dev_lstats_read(dev, packets, bytes);
 331         return atomic64_read(&priv->dropped);
 332 }
 333
 334 static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
 335 {
 336         struct veth_priv *priv = netdev_priv(dev);
 337         int i;
 338
 339         result->peer_tq_xdp_xmit_err = 0;
 340         result->xdp_packets = 0;
 341         result->xdp_tx_err = 0;
 342         result->xdp_bytes = 0;
 343         result->rx_drops = 0;
 344         for (i = 0; i < dev->num_rx_queues; i++) {
 345                 u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
 346                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 347                 unsigned int start;
 348
 349                 do {
 350                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 351                         peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
 352                         xdp_tx_err = stats->vs.xdp_tx_err;
 353                         packets = stats->vs.xdp_packets;
 354                         bytes = stats->vs.xdp_bytes;
 355                         drops = stats->vs.rx_drops;
 356                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 357                 result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
 358                 result->xdp_tx_err += xdp_tx_err;
 359                 result->xdp_packets += packets;
 360                 result->xdp_bytes += bytes;
 361                 result->rx_drops += drops;
 362         }
 363 }
 364
 365 static void veth_get_stats64(struct net_device *dev,
 366                              struct rtnl_link_stats64 *tot)
 367 {
 368         struct veth_priv *priv = netdev_priv(dev);
 369         struct net_device *peer;
 370         struct veth_stats rx;
 371         u64 packets, bytes;
 372
 373         tot->tx_dropped = veth_stats_tx(dev, &packets, &bytes);
 374         tot->tx_bytes = bytes;
 375         tot->tx_packets = packets;
 376
 377         veth_stats_rx(&rx, dev);
 378         tot->tx_dropped += rx.xdp_tx_err;
 379         tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
 380         tot->rx_bytes = rx.xdp_bytes;
 381         tot->rx_packets = rx.xdp_packets;
 382
 383         rcu_read_lock();
 384         peer = rcu_dereference(priv->peer);
 385         if (peer) {
 386                 veth_stats_tx(peer, &packets, &bytes);
 387                 tot->rx_bytes += bytes;
 388                 tot->rx_packets += packets;
 389
 390                 veth_stats_rx(&rx, peer);
 391                 tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
 392                 tot->rx_dropped += rx.xdp_tx_err;
 393                 tot->tx_bytes += rx.xdp_bytes;
 394                 tot->tx_packets += rx.xdp_packets;
 395         }
 396         rcu_read_unlock();
 397 }
 398
 399 /* fake multicast ability */
 400 static void veth_set_multicast_list(struct net_device *dev)
 401 {
 402 }
 403
 404 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 405                                       int buflen)
 406 {
 407         struct sk_buff *skb;
 408
 409         skb = build_skb(head, buflen);
 410         if (!skb)
 411                 return NULL;
 412
 413         skb_reserve(skb, headroom);
 414         skb_put(skb, len);
 415
 416         return skb;
 417 }
 418
 419 static int veth_select_rxq(struct net_device *dev)
 420 {
 421         return smp_processor_id() % dev->real_num_rx_queues;
 422 }
 423
 424 static struct net_device *veth_peer_dev(struct net_device *dev)
 425 {
 426         struct veth_priv *priv = netdev_priv(dev);
 427
 428         /* Callers must be under RCU read side. */
 429         return rcu_dereference(priv->peer);
 430 }
 431
 432 static int veth_xdp_xmit(struct net_device *dev, int n,
 433                          struct xdp_frame **frames,
 434                          u32 flags, bool ndo_xmit)
 435 {
 436         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 437         int i, ret = -ENXIO, drops = 0;
 438         struct net_device *rcv;
 439         unsigned int max_len;
 440         struct veth_rq *rq;
 441
 442         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
 443                 return -EINVAL;
 444
 445         rcu_read_lock();
 446         rcv = rcu_dereference(priv->peer);
 447         if (unlikely(!rcv))
 448                 goto out;
 449
 450         rcv_priv = netdev_priv(rcv);
 451         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 452         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 453          * side. This means an XDP program is loaded on the peer and the peer
 454          * device is up.
 455          */
 456         if (!rcu_access_pointer(rq->xdp_prog))
 457                 goto out;
 458
 459         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 460
 461         spin_lock(&rq->xdp_ring.producer_lock);
 462         for (i = 0; i < n; i++) {
 463                 struct xdp_frame *frame = frames[i];
 464                 void *ptr = veth_xdp_to_ptr(frame);
 465
 466                 if (unlikely(frame->len > max_len ||
 467                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 468                         xdp_return_frame_rx_napi(frame);
 469                         drops++;
 470                 }
 471         }
 472         spin_unlock(&rq->xdp_ring.producer_lock);
 473
 474         if (flags & XDP_XMIT_FLUSH)
 475                 __veth_xdp_flush(rq);
 476
 477         ret = n - drops;
 478         if (ndo_xmit) {
 479                 u64_stats_update_begin(&rq->stats.syncp);
 480                 rq->stats.vs.peer_tq_xdp_xmit += n - drops;
 481                 rq->stats.vs.peer_tq_xdp_xmit_err += drops;
 482                 u64_stats_update_end(&rq->stats.syncp);
 483         }
 484
 485 out:
 486         rcu_read_unlock();
 487
 488         return ret;
 489 }
 490
 491 static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
 492                              struct xdp_frame **frames, u32 flags)
 493 {
 494         int err;
 495
 496         err = veth_xdp_xmit(dev, n, frames, flags, true);
 497         if (err < 0) {
 498                 struct veth_priv *priv = netdev_priv(dev);
 499
 500                 atomic64_add(n, &priv->dropped);
 501         }
 502
 503         return err;
 504 }
 505
 506 static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
 507 {
 508         int sent, i, err = 0;
 509
 510         sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
 511         if (sent < 0) {
 512                 err = sent;
 513                 sent = 0;
 514                 for (i = 0; i < bq->count; i++)
 515                         xdp_return_frame(bq->q[i]);
 516         }
 517         trace_xdp_bulk_tx(rq->dev, sent, bq->count - sent, err);
 518
 519         u64_stats_update_begin(&rq->stats.syncp);
 520         rq->stats.vs.xdp_tx += sent;
 521         rq->stats.vs.xdp_tx_err += bq->count - sent;
 522         u64_stats_update_end(&rq->stats.syncp);
 523
 524         bq->count = 0;
 525 }
 526
 527 static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
 528 {
 529         struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
 530         struct net_device *rcv;
 531         struct veth_rq *rcv_rq;
 532
 533         rcu_read_lock();
 534         veth_xdp_flush_bq(rq, bq);
 535         rcv = rcu_dereference(priv->peer);
 536         if (unlikely(!rcv))
 537                 goto out;
 538
 539         rcv_priv = netdev_priv(rcv);
 540         rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 541         /* xdp_ring is initialized on receive side? */
 542         if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
 543                 goto out;
 544
 545         __veth_xdp_flush(rcv_rq);
 546 out:
 547         rcu_read_unlock();
 548 }
 549
 550 static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
 551                        struct veth_xdp_tx_bq *bq)
 552 {
 553         struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
 554
 555         if (unlikely(!frame))
 556                 return -EOVERFLOW;
 557
 558         if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
 559                 veth_xdp_flush_bq(rq, bq);
 560
 561         bq->q[bq->count++] = frame;
 562
 563         return 0;
 564 }
 565
 566 static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
 567                                           struct xdp_frame *frame,
 568                                           struct veth_xdp_tx_bq *bq,
 569                                           struct veth_stats *stats)
 570 {
 571         struct xdp_frame orig_frame;
 572         struct bpf_prog *xdp_prog;
 573
 574         rcu_read_lock();
 575         xdp_prog = rcu_dereference(rq->xdp_prog);
 576         if (likely(xdp_prog)) {
 577                 struct xdp_buff xdp;
 578                 u32 act;
 579
 580                 xdp_convert_frame_to_buff(frame, &xdp);
 581                 xdp.rxq = &rq->xdp_rxq;
 582
 583                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 584
 585                 switch (act) {
 586                 case XDP_PASS:
 587                         if (xdp_update_frame_from_buff(&xdp, frame))
 588                                 goto err_xdp;
 589                         break;
 590                 case XDP_TX:
 591                         orig_frame = *frame;
 592                         xdp.rxq->mem = frame->mem;
 593                         if (unlikely(veth_xdp_tx(rq, &xdp, bq) < 0)) {
 594                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 595                                 frame = &orig_frame;
 596                                 stats->rx_drops++;
 597                                 goto err_xdp;
 598                         }
 599                         stats->xdp_tx++;
 600                         rcu_read_unlock();
 601                         goto xdp_xmit;
 602                 case XDP_REDIRECT:
 603                         orig_frame = *frame;
 604                         xdp.rxq->mem = frame->mem;
 605                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 606                                 frame = &orig_frame;
 607                                 stats->rx_drops++;
 608                                 goto err_xdp;
 609                         }
 610                         stats->xdp_redirect++;
 611                         rcu_read_unlock();
 612                         goto xdp_xmit;
 613                 default:
 614                         bpf_warn_invalid_xdp_action(act);
 615                         fallthrough;
 616                 case XDP_ABORTED:
 617                         trace_xdp_exception(rq->dev, xdp_prog, act);
 618                         fallthrough;
 619                 case XDP_DROP:
 620                         stats->xdp_drops++;
 621                         goto err_xdp;
 622                 }
 623         }
 624         rcu_read_unlock();
 625
 626         return frame;
 627 err_xdp:
 628         rcu_read_unlock();
 629         xdp_return_frame(frame);
 630 xdp_xmit:
 631         return NULL;
 632 }
 633
 634 /* frames array contains VETH_XDP_BATCH at most */
 635 static void veth_xdp_rcv_bulk_skb(struct veth_rq *rq, void **frames,
 636                                   int n_xdpf, struct veth_xdp_tx_bq *bq,
 637                                   struct veth_stats *stats)
 638 {
 639         void *skbs[VETH_XDP_BATCH];
 640         int i;
 641
 642         if (xdp_alloc_skb_bulk(skbs, n_xdpf,
 643                                GFP_ATOMIC | __GFP_ZERO) < 0) {
 644                 for (i = 0; i < n_xdpf; i++)
 645                         xdp_return_frame(frames[i]);
 646                 stats->rx_drops += n_xdpf;
 647
 648                 return;
 649         }
 650
 651         for (i = 0; i < n_xdpf; i++) {
 652                 struct sk_buff *skb = skbs[i];
 653
 654                 skb = __xdp_build_skb_from_frame(frames[i], skb,
 655                                                  rq->dev);
 656                 if (!skb) {
 657                         xdp_return_frame(frames[i]);
 658                         stats->rx_drops++;
 659                         continue;
 660                 }
 661                 napi_gro_receive(&rq->xdp_napi, skb);
 662         }
 663 }
 664
 665 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
 666                                         struct sk_buff *skb,
 667                                         struct veth_xdp_tx_bq *bq,
 668                                         struct veth_stats *stats)
 669 {
 670         u32 pktlen, headroom, act, metalen, frame_sz;
 671         void *orig_data, *orig_data_end;
 672         struct bpf_prog *xdp_prog;
 673         int mac_len, delta, off;
 674         struct xdp_buff xdp;
 675
 676         skb_orphan(skb);
 677
 678         rcu_read_lock();
 679         xdp_prog = rcu_dereference(rq->xdp_prog);
 680         if (unlikely(!xdp_prog)) {
 681                 rcu_read_unlock();
 682                 goto out;
 683         }
 684
 685         mac_len = skb->data - skb_mac_header(skb);
 686         pktlen = skb->len + mac_len;
 687         headroom = skb_headroom(skb) - mac_len;
 688
 689         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 690             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 691                 struct sk_buff *nskb;
 692                 int size, head_off;
 693                 void *head, *start;
 694                 struct page *page;
 695
 696                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 697                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 698                 if (size > PAGE_SIZE)
 699                         goto drop;
 700
 701                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 702                 if (!page)
 703                         goto drop;
 704
 705                 head = page_address(page);
 706                 start = head + VETH_XDP_HEADROOM;
 707                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 708                         page_frag_free(head);
 709                         goto drop;
 710                 }
 711
 712                 nskb = veth_build_skb(head, VETH_XDP_HEADROOM + mac_len,
 713                                       skb->len, PAGE_SIZE);
 714                 if (!nskb) {
 715                         page_frag_free(head);
 716                         goto drop;
 717                 }
 718
 719                 skb_copy_header(nskb, skb);
 720                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 721                 skb_headers_offset_update(nskb, head_off);
 722                 consume_skb(skb);
 723                 skb = nskb;
 724         }
 725
 726         /* SKB "head" area always have tailroom for skb_shared_info */
 727         frame_sz = skb_end_pointer(skb) - skb->head;
 728         frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 729         xdp_init_buff(&xdp, frame_sz, &rq->xdp_rxq);
 730         xdp_prepare_buff(&xdp, skb->head, skb->mac_header, pktlen, true);
 731
 732         orig_data = xdp.data;
 733         orig_data_end = xdp.data_end;
 734
 735         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 736
 737         switch (act) {
 738         case XDP_PASS:
 739                 break;
 740         case XDP_TX:
 741                 get_page(virt_to_page(xdp.data));
 742                 consume_skb(skb);
 743                 xdp.rxq->mem = rq->xdp_mem;
 744                 if (unlikely(veth_xdp_tx(rq, &xdp, bq) < 0)) {
 745                         trace_xdp_exception(rq->dev, xdp_prog, act);
 746                         stats->rx_drops++;
 747                         goto err_xdp;
 748                 }
 749                 stats->xdp_tx++;
 750                 rcu_read_unlock();
 751                 goto xdp_xmit;
 752         case XDP_REDIRECT:
 753                 get_page(virt_to_page(xdp.data));
 754                 consume_skb(skb);
 755                 xdp.rxq->mem = rq->xdp_mem;
 756                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 757                         stats->rx_drops++;
 758                         goto err_xdp;
 759                 }
 760                 stats->xdp_redirect++;
 761                 rcu_read_unlock();
 762                 goto xdp_xmit;
 763         default:
 764                 bpf_warn_invalid_xdp_action(act);
 765                 fallthrough;
 766         case XDP_ABORTED:
 767                 trace_xdp_exception(rq->dev, xdp_prog, act);
 768                 fallthrough;
 769         case XDP_DROP:
 770                 stats->xdp_drops++;
 771                 goto xdp_drop;
 772         }
 773         rcu_read_unlock();
 774
 775         /* check if bpf_xdp_adjust_head was used */
 776         delta = orig_data - xdp.data;
 777         off = mac_len + delta;
 778         if (off > 0)
 779                 __skb_push(skb, off);
 780         else if (off < 0)
 781                 __skb_pull(skb, -off);
 782         skb->mac_header -= delta;
 783
 784         /* check if bpf_xdp_adjust_tail was used */
 785         off = xdp.data_end - orig_data_end;
 786         if (off != 0)
 787                 __skb_put(skb, off); /* positive on grow, negative on shrink */
 788         skb->protocol = eth_type_trans(skb, rq->dev);
 789
 790         metalen = xdp.data - xdp.data_meta;
 791         if (metalen)
 792                 skb_metadata_set(skb, metalen);
 793 out:
 794         return skb;
 795 drop:
 796         stats->rx_drops++;
 797 xdp_drop:
 798         rcu_read_unlock();
 799         kfree_skb(skb);
 800         return NULL;
 801 err_xdp:
 802         rcu_read_unlock();
 803         page_frag_free(xdp.data);
 804 xdp_xmit:
 805         return NULL;
 806 }
 807
 808 static int veth_xdp_rcv(struct veth_rq *rq, int budget,
 809                         struct veth_xdp_tx_bq *bq,
 810                         struct veth_stats *stats)
 811 {
 812         int i, done = 0, n_xdpf = 0;
 813         void *xdpf[VETH_XDP_BATCH];
 814
 815         for (i = 0; i < budget; i++) {
 816                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 817
 818                 if (!ptr)
 819                         break;
 820
 821                 if (veth_is_xdp_frame(ptr)) {
 822                         /* ndo_xdp_xmit */
 823                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 824
 825                         stats->xdp_bytes += frame->len;
 826                         frame = veth_xdp_rcv_one(rq, frame, bq, stats);
 827                         if (frame) {
 828                                 /* XDP_PASS */
 829                                 xdpf[n_xdpf++] = frame;
 830                                 if (n_xdpf == VETH_XDP_BATCH) {
 831                                         veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf,
 832                                                               bq, stats);
 833                                         n_xdpf = 0;
 834                                 }
 835                         }
 836                 } else {
 837                         /* ndo_start_xmit */
 838                         struct sk_buff *skb = ptr;
 839
 840                         stats->xdp_bytes += skb->len;
 841                         skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
 842                         if (skb)
 843                                 napi_gro_receive(&rq->xdp_napi, skb);
 844                 }
 845                 done++;
 846         }
 847
 848         if (n_xdpf)
 849                 veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf, bq, stats);
 850
 851         u64_stats_update_begin(&rq->stats.syncp);
 852         rq->stats.vs.xdp_redirect += stats->xdp_redirect;
 853         rq->stats.vs.xdp_bytes += stats->xdp_bytes;
 854         rq->stats.vs.xdp_drops += stats->xdp_drops;
 855         rq->stats.vs.rx_drops += stats->rx_drops;
 856         rq->stats.vs.xdp_packets += done;
 857         u64_stats_update_end(&rq->stats.syncp);
 858
 859         return done;
 860 }
 861
 862 static int veth_poll(struct napi_struct *napi, int budget)
 863 {
 864         struct veth_rq *rq =
 865                 container_of(napi, struct veth_rq, xdp_napi);
 866         struct veth_stats stats = {};
 867         struct veth_xdp_tx_bq bq;
 868         int done;
 869
 870         bq.count = 0;
 871
 872         xdp_set_return_frame_no_direct();
 873         done = veth_xdp_rcv(rq, budget, &bq, &stats);
 874
 875         if (done < budget && napi_complete_done(napi, done)) {
 876                 /* Write rx_notify_masked before reading ptr_ring */
 877                 smp_store_mb(rq->rx_notify_masked, false);
 878                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 879                         rq->rx_notify_masked = true;
 880                         napi_schedule(&rq->xdp_napi);
 881                 }
 882         }
 883
 884         if (stats.xdp_tx > 0)
 885                 veth_xdp_flush(rq, &bq);
 886         if (stats.xdp_redirect > 0)
 887                 xdp_do_flush();
 888         xdp_clear_return_frame_no_direct();
 889
 890         return done;
 891 }
 892
 893 static int veth_napi_add(struct net_device *dev)
 894 {
 895         struct veth_priv *priv = netdev_priv(dev);
 896         int err, i;
 897
 898         for (i = 0; i < dev->real_num_rx_queues; i++) {
 899                 struct veth_rq *rq = &priv->rq[i];
 900
 901                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 902                 if (err)
 903                         goto err_xdp_ring;
 904         }
 905
 906         for (i = 0; i < dev->real_num_rx_queues; i++) {
 907                 struct veth_rq *rq = &priv->rq[i];
 908
 909                 napi_enable(&rq->xdp_napi);
 910         }
 911
 912         return 0;
 913 err_xdp_ring:
 914         for (i--; i >= 0; i--)
 915                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 916
 917         return err;
 918 }
 919
 920 static void veth_napi_del(struct net_device *dev)
 921 {
 922         struct veth_priv *priv = netdev_priv(dev);
 923         int i;
 924
 925         for (i = 0; i < dev->real_num_rx_queues; i++) {
 926                 struct veth_rq *rq = &priv->rq[i];
 927
 928                 napi_disable(&rq->xdp_napi);
 929                 __netif_napi_del(&rq->xdp_napi);
 930         }
 931         synchronize_net();
 932
 933         for (i = 0; i < dev->real_num_rx_queues; i++) {
 934                 struct veth_rq *rq = &priv->rq[i];
 935
 936                 rq->rx_notify_masked = false;
 937                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 938         }
 939 }
 940
 941 static int veth_enable_xdp(struct net_device *dev)
 942 {
 943         struct veth_priv *priv = netdev_priv(dev);
 944         int err, i;
 945
 946         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 947                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 948                         struct veth_rq *rq = &priv->rq[i];
 949
 950                         netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 951                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
 952                         if (err < 0)
 953                                 goto err_rxq_reg;
 954
 955                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 956                                                          MEM_TYPE_PAGE_SHARED,
 957                                                          NULL);
 958                         if (err < 0)
 959                                 goto err_reg_mem;
 960
 961                         /* Save original mem info as it can be overwritten */
 962                         rq->xdp_mem = rq->xdp_rxq.mem;
 963                 }
 964
 965                 err = veth_napi_add(dev);
 966                 if (err)
 967                         goto err_rxq_reg;
 968         }
 969
 970         for (i = 0; i < dev->real_num_rx_queues; i++)
 971                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 972
 973         return 0;
 974 err_reg_mem:
 975         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 976 err_rxq_reg:
 977         for (i--; i >= 0; i--) {
 978                 struct veth_rq *rq = &priv->rq[i];
 979
 980                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 981                 netif_napi_del(&rq->xdp_napi);
 982         }
 983
 984         return err;
 985 }
 986
 987 static void veth_disable_xdp(struct net_device *dev)
 988 {
 989         struct veth_priv *priv = netdev_priv(dev);
 990         int i;
 991
 992         for (i = 0; i < dev->real_num_rx_queues; i++)
 993                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 994         veth_napi_del(dev);
 995         for (i = 0; i < dev->real_num_rx_queues; i++) {
 996                 struct veth_rq *rq = &priv->rq[i];
 997
 998                 rq->xdp_rxq.mem = rq->xdp_mem;
 999                 xdp_rxq_info_unreg(&rq->xdp_rxq);
1000         }
1001 }
1002
1003 static int veth_open(struct net_device *dev)
1004 {
1005         struct veth_priv *priv = netdev_priv(dev);
1006         struct net_device *peer = rtnl_dereference(priv->peer);
1007         int err;
1008
1009         if (!peer)
1010                 return -ENOTCONN;
1011
1012         if (priv->_xdp_prog) {
1013                 err = veth_enable_xdp(dev);
1014                 if (err)
1015                         return err;
1016         }
1017
1018         if (peer->flags & IFF_UP) {
1019                 netif_carrier_on(dev);
1020                 netif_carrier_on(peer);
1021         }
1022
1023         return 0;
1024 }
1025
1026 static int veth_close(struct net_device *dev)
1027 {
1028         struct veth_priv *priv = netdev_priv(dev);
1029         struct net_device *peer = rtnl_dereference(priv->peer);
1030
1031         netif_carrier_off(dev);
1032         if (peer)
1033                 netif_carrier_off(peer);
1034
1035         if (priv->_xdp_prog)
1036                 veth_disable_xdp(dev);
1037
1038         return 0;
1039 }
1040
1041 static int is_valid_veth_mtu(int mtu)
1042 {
1043         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
1044 }
1045
1046 static int veth_alloc_queues(struct net_device *dev)
1047 {
1048         struct veth_priv *priv = netdev_priv(dev);
1049         int i;
1050
1051         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
1052         if (!priv->rq)
1053                 return -ENOMEM;
1054
1055         for (i = 0; i < dev->num_rx_queues; i++) {
1056                 priv->rq[i].dev = dev;
1057                 u64_stats_init(&priv->rq[i].stats.syncp);
1058         }
1059
1060         return 0;
1061 }
1062
1063 static void veth_free_queues(struct net_device *dev)
1064 {
1065         struct veth_priv *priv = netdev_priv(dev);
1066
1067         kfree(priv->rq);
1068 }
1069
1070 static int veth_dev_init(struct net_device *dev)
1071 {
1072         int err;
1073
1074         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
1075         if (!dev->lstats)
1076                 return -ENOMEM;
1077
1078         err = veth_alloc_queues(dev);
1079         if (err) {
1080                 free_percpu(dev->lstats);
1081                 return err;
1082         }
1083
1084         return 0;
1085 }
1086
1087 static void veth_dev_free(struct net_device *dev)
1088 {
1089         veth_free_queues(dev);
1090         free_percpu(dev->lstats);
1091 }
1092
1093 #ifdef CONFIG_NET_POLL_CONTROLLER
1094 static void veth_poll_controller(struct net_device *dev)
1095 {
1096         /* veth only receives frames when its peer sends one
1097          * Since it has nothing to do with disabling irqs, we are guaranteed
1098          * never to have pending data when we poll for it so
1099          * there is nothing to do here.
1100          *
1101          * We need this though so netpoll recognizes us as an interface that
1102          * supports polling, which enables bridge devices in virt setups to
1103          * still use netconsole
1104          */
1105 }
1106 #endif  /* CONFIG_NET_POLL_CONTROLLER */
1107
1108 static int veth_get_iflink(const struct net_device *dev)
1109 {
1110         struct veth_priv *priv = netdev_priv(dev);
1111         struct net_device *peer;
1112         int iflink;
1113
1114         rcu_read_lock();
1115         peer = rcu_dereference(priv->peer);
1116         iflink = peer ? peer->ifindex : 0;
1117         rcu_read_unlock();
1118
1119         return iflink;
1120 }
1121
1122 static netdev_features_t veth_fix_features(struct net_device *dev,
1123                                            netdev_features_t features)
1124 {
1125         struct veth_priv *priv = netdev_priv(dev);
1126         struct net_device *peer;
1127
1128         peer = rtnl_dereference(priv->peer);
1129         if (peer) {
1130                 struct veth_priv *peer_priv = netdev_priv(peer);
1131
1132                 if (peer_priv->_xdp_prog)
1133                         features &= ~NETIF_F_GSO_SOFTWARE;
1134         }
1135
1136         return features;
1137 }
1138
1139 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1140 {
1141         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1142         struct net_device *peer;
1143
1144         if (new_hr < 0)
1145                 new_hr = 0;
1146
1147         rcu_read_lock();
1148         peer = rcu_dereference(priv->peer);
1149         if (unlikely(!peer))
1150                 goto out;
1151
1152         peer_priv = netdev_priv(peer);
1153         priv->requested_headroom = new_hr;
1154         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1155         dev->needed_headroom = new_hr;
1156         peer->needed_headroom = new_hr;
1157
1158 out:
1159         rcu_read_unlock();
1160 }
1161
1162 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1163                         struct netlink_ext_ack *extack)
1164 {
1165         struct veth_priv *priv = netdev_priv(dev);
1166         struct bpf_prog *old_prog;
1167         struct net_device *peer;
1168         unsigned int max_mtu;
1169         int err;
1170
1171         old_prog = priv->_xdp_prog;
1172         priv->_xdp_prog = prog;
1173         peer = rtnl_dereference(priv->peer);
1174
1175         if (prog) {
1176                 if (!peer) {
1177                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1178                         err = -ENOTCONN;
1179                         goto err;
1180                 }
1181
1182                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
1183                           peer->hard_header_len -
1184                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1185                 if (peer->mtu > max_mtu) {
1186                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1187                         err = -ERANGE;
1188                         goto err;
1189                 }
1190
1191                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1192                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1193                         err = -ENOSPC;
1194                         goto err;
1195                 }
1196
1197                 if (dev->flags & IFF_UP) {
1198                         err = veth_enable_xdp(dev);
1199                         if (err) {
1200                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1201                                 goto err;
1202                         }
1203                 }
1204
1205                 if (!old_prog) {
1206                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1207                         peer->max_mtu = max_mtu;
1208                 }
1209         }
1210
1211         if (old_prog) {
1212                 if (!prog) {
1213                         if (dev->flags & IFF_UP)
1214                                 veth_disable_xdp(dev);
1215
1216                         if (peer) {
1217                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1218                                 peer->max_mtu = ETH_MAX_MTU;
1219                         }
1220                 }
1221                 bpf_prog_put(old_prog);
1222         }
1223
1224         if ((!!old_prog ^ !!prog) && peer)
1225                 netdev_update_features(peer);
1226
1227         return 0;
1228 err:
1229         priv->_xdp_prog = old_prog;
1230
1231         return err;
1232 }
1233
1234 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1235 {
1236         switch (xdp->command) {
1237         case XDP_SETUP_PROG:
1238                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1239         default:
1240                 return -EINVAL;
1241         }
1242 }
1243
1244 static const struct net_device_ops veth_netdev_ops = {
1245         .ndo_init            = veth_dev_init,
1246         .ndo_open            = veth_open,
1247         .ndo_stop            = veth_close,
1248         .ndo_start_xmit      = veth_xmit,
1249         .ndo_get_stats64     = veth_get_stats64,
1250         .ndo_set_rx_mode     = veth_set_multicast_list,
1251         .ndo_set_mac_address = eth_mac_addr,
1252 #ifdef CONFIG_NET_POLL_CONTROLLER
1253         .ndo_poll_controller    = veth_poll_controller,
1254 #endif
1255         .ndo_get_iflink         = veth_get_iflink,
1256         .ndo_fix_features       = veth_fix_features,
1257         .ndo_features_check     = passthru_features_check,
1258         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1259         .ndo_bpf                = veth_xdp,
1260         .ndo_xdp_xmit           = veth_ndo_xdp_xmit,
1261         .ndo_get_peer_dev       = veth_peer_dev,
1262 };
1263
1264 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1265                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1266                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1267                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1268                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1269
1270 static void veth_setup(struct net_device *dev)
1271 {
1272         ether_setup(dev);
1273
1274         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1275         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1276         dev->priv_flags |= IFF_NO_QUEUE;
1277         dev->priv_flags |= IFF_PHONY_HEADROOM;
1278
1279         dev->netdev_ops = &veth_netdev_ops;
1280         dev->ethtool_ops = &veth_ethtool_ops;
1281         dev->features |= NETIF_F_LLTX;
1282         dev->features |= VETH_FEATURES;
1283         dev->vlan_features = dev->features &
1284                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1285                                NETIF_F_HW_VLAN_STAG_TX |
1286                                NETIF_F_HW_VLAN_CTAG_RX |
1287                                NETIF_F_HW_VLAN_STAG_RX);
1288         dev->needs_free_netdev = true;
1289         dev->priv_destructor = veth_dev_free;
1290         dev->max_mtu = ETH_MAX_MTU;
1291
1292         dev->hw_features = VETH_FEATURES;
1293         dev->hw_enc_features = VETH_FEATURES;
1294         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1295 }
1296
1297 /*
1298  * netlink interface
1299  */
1300
1301 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1302                          struct netlink_ext_ack *extack)
1303 {
1304         if (tb[IFLA_ADDRESS]) {
1305                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1306                         return -EINVAL;
1307                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1308                         return -EADDRNOTAVAIL;
1309         }
1310         if (tb[IFLA_MTU]) {
1311                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1312                         return -EINVAL;
1313         }
1314         return 0;
1315 }
1316
1317 static struct rtnl_link_ops veth_link_ops;
1318
1319 static int veth_newlink(struct net *src_net, struct net_device *dev,
1320                         struct nlattr *tb[], struct nlattr *data[],
1321                         struct netlink_ext_ack *extack)
1322 {
1323         int err;
1324         struct net_device *peer;
1325         struct veth_priv *priv;
1326         char ifname[IFNAMSIZ];
1327         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1328         unsigned char name_assign_type;
1329         struct ifinfomsg *ifmp;
1330         struct net *net;
1331
1332         /*
1333          * create and register peer first
1334          */
1335         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1336                 struct nlattr *nla_peer;
1337
1338                 nla_peer = data[VETH_INFO_PEER];
1339                 ifmp = nla_data(nla_peer);
1340                 err = rtnl_nla_parse_ifla(peer_tb,
1341                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1342                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1343                                           NULL);
1344                 if (err < 0)
1345                         return err;
1346
1347                 err = veth_validate(peer_tb, NULL, extack);
1348                 if (err < 0)
1349                         return err;
1350
1351                 tbp = peer_tb;
1352         } else {
1353                 ifmp = NULL;
1354                 tbp = tb;
1355         }
1356
1357         if (ifmp && tbp[IFLA_IFNAME]) {
1358                 nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1359                 name_assign_type = NET_NAME_USER;
1360         } else {
1361                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1362                 name_assign_type = NET_NAME_ENUM;
1363         }
1364
1365         net = rtnl_link_get_net(src_net, tbp);
1366         if (IS_ERR(net))
1367                 return PTR_ERR(net);
1368
1369         peer = rtnl_create_link(net, ifname, name_assign_type,
1370                                 &veth_link_ops, tbp, extack);
1371         if (IS_ERR(peer)) {
1372                 put_net(net);
1373                 return PTR_ERR(peer);
1374         }
1375
1376         if (!ifmp || !tbp[IFLA_ADDRESS])
1377                 eth_hw_addr_random(peer);
1378
1379         if (ifmp && (dev->ifindex != 0))
1380                 peer->ifindex = ifmp->ifi_index;
1381
1382         peer->gso_max_size = dev->gso_max_size;
1383         peer->gso_max_segs = dev->gso_max_segs;
1384
1385         err = register_netdevice(peer);
1386         put_net(net);
1387         net = NULL;
1388         if (err < 0)
1389                 goto err_register_peer;
1390
1391         netif_carrier_off(peer);
1392
1393         err = rtnl_configure_link(peer, ifmp);
1394         if (err < 0)
1395                 goto err_configure_peer;
1396
1397         /*
1398          * register dev last
1399          *
1400          * note, that since we've registered new device the dev's name
1401          * should be re-allocated
1402          */
1403
1404         if (tb[IFLA_ADDRESS] == NULL)
1405                 eth_hw_addr_random(dev);
1406
1407         if (tb[IFLA_IFNAME])
1408                 nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1409         else
1410                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1411
1412         err = register_netdevice(dev);
1413         if (err < 0)
1414                 goto err_register_dev;
1415
1416         netif_carrier_off(dev);
1417
1418         /*
1419          * tie the deviced together
1420          */
1421
1422         priv = netdev_priv(dev);
1423         rcu_assign_pointer(priv->peer, peer);
1424
1425         priv = netdev_priv(peer);
1426         rcu_assign_pointer(priv->peer, dev);
1427
1428         return 0;
1429
1430 err_register_dev:
1431         /* nothing to do */
1432 err_configure_peer:
1433         unregister_netdevice(peer);
1434         return err;
1435
1436 err_register_peer:
1437         free_netdev(peer);
1438         return err;
1439 }
1440
1441 static void veth_dellink(struct net_device *dev, struct list_head *head)
1442 {
1443         struct veth_priv *priv;
1444         struct net_device *peer;
1445
1446         priv = netdev_priv(dev);
1447         peer = rtnl_dereference(priv->peer);
1448
1449         /* Note : dellink() is called from default_device_exit_batch(),
1450          * before a rcu_synchronize() point. The devices are guaranteed
1451          * not being freed before one RCU grace period.
1452          */
1453         RCU_INIT_POINTER(priv->peer, NULL);
1454         unregister_netdevice_queue(dev, head);
1455
1456         if (peer) {
1457                 priv = netdev_priv(peer);
1458                 RCU_INIT_POINTER(priv->peer, NULL);
1459                 unregister_netdevice_queue(peer, head);
1460         }
1461 }
1462
1463 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1464         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1465 };
1466
1467 static struct net *veth_get_link_net(const struct net_device *dev)
1468 {
1469         struct veth_priv *priv = netdev_priv(dev);
1470         struct net_device *peer = rtnl_dereference(priv->peer);
1471
1472         return peer ? dev_net(peer) : dev_net(dev);
1473 }
1474
1475 static struct rtnl_link_ops veth_link_ops = {
1476         .kind           = DRV_NAME,
1477         .priv_size      = sizeof(struct veth_priv),
1478         .setup          = veth_setup,
1479         .validate       = veth_validate,
1480         .newlink        = veth_newlink,
1481         .dellink        = veth_dellink,
1482         .policy         = veth_policy,
1483         .maxtype        = VETH_INFO_MAX,
1484         .get_link_net   = veth_get_link_net,
1485 };
1486
1487 /*
1488  * init/fini
1489  */
1490
1491 static __init int veth_init(void)
1492 {
1493         return rtnl_link_register(&veth_link_ops);
1494 }
1495
1496 static __exit void veth_exit(void)
1497 {
1498         rtnl_link_unregister(&veth_link_ops);
1499 }
1500
1501 module_init(veth_init);
1502 module_exit(veth_exit);
1503
1504 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1505 MODULE_LICENSE("GPL v2");
1506 MODULE_ALIAS_RTNL_LINK(DRV_NAME);