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