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 napi_struct __rcu *napi; /* points to xdp_napi when the latter is initialized */
  61         struct net_device       *dev;
  62         struct bpf_prog __rcu   *xdp_prog;
  63         struct xdp_mem_info     xdp_mem;
  64         struct veth_rq_stats    stats;
  65         bool                    rx_notify_masked;
  66         struct ptr_ring         xdp_ring;
  67         struct xdp_rxq_info     xdp_rxq;
  68 };
  69
  70 struct veth_priv {
  71         struct net_device __rcu *peer;
  72         atomic64_t              dropped;
  73         struct bpf_prog         *_xdp_prog;
  74         struct veth_rq          *rq;
  75         unsigned int            requested_headroom;
  76 };
  77
  78 struct veth_xdp_tx_bq {
  79         struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
  80         unsigned int count;
  81 };
  82
  83 /*
  84  * ethtool interface
  85  */
  86
  87 struct veth_q_stat_desc {
  88         char    desc[ETH_GSTRING_LEN];
  89         size_t  offset;
  90 };
  91
  92 #define VETH_RQ_STAT(m) offsetof(struct veth_stats, m)
  93
  94 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
  95         { "xdp_packets",        VETH_RQ_STAT(xdp_packets) },
  96         { "xdp_bytes",          VETH_RQ_STAT(xdp_bytes) },
  97         { "drops",              VETH_RQ_STAT(rx_drops) },
  98         { "xdp_redirect",       VETH_RQ_STAT(xdp_redirect) },
  99         { "xdp_drops",          VETH_RQ_STAT(xdp_drops) },
 100         { "xdp_tx",             VETH_RQ_STAT(xdp_tx) },
 101         { "xdp_tx_errors",      VETH_RQ_STAT(xdp_tx_err) },
 102 };
 103
 104 #define VETH_RQ_STATS_LEN       ARRAY_SIZE(veth_rq_stats_desc)
 105
 106 static const struct veth_q_stat_desc veth_tq_stats_desc[] = {
 107         { "xdp_xmit",           VETH_RQ_STAT(peer_tq_xdp_xmit) },
 108         { "xdp_xmit_errors",    VETH_RQ_STAT(peer_tq_xdp_xmit_err) },
 109 };
 110
 111 #define VETH_TQ_STATS_LEN       ARRAY_SIZE(veth_tq_stats_desc)
 112
 113 static struct {
 114         const char string[ETH_GSTRING_LEN];
 115 } ethtool_stats_keys[] = {
 116         { "peer_ifindex" },
 117 };
 118
 119 static int veth_get_link_ksettings(struct net_device *dev,
 120                                    struct ethtool_link_ksettings *cmd)
 121 {
 122         cmd->base.speed         = SPEED_10000;
 123         cmd->base.duplex        = DUPLEX_FULL;
 124         cmd->base.port          = PORT_TP;
 125         cmd->base.autoneg       = AUTONEG_DISABLE;
 126         return 0;
 127 }
 128
 129 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 130 {
 131         strscpy(info->driver, DRV_NAME, sizeof(info->driver));
 132         strscpy(info->version, DRV_VERSION, sizeof(info->version));
 133 }
 134
 135 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
 136 {
 137         u8 *p = buf;
 138         int i, j;
 139
 140         switch(stringset) {
 141         case ETH_SS_STATS:
 142                 memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
 143                 p += sizeof(ethtool_stats_keys);
 144                 for (i = 0; i < dev->real_num_rx_queues; i++)
 145                         for (j = 0; j < VETH_RQ_STATS_LEN; j++)
 146                                 ethtool_sprintf(&p, "rx_queue_%u_%.18s",
 147                                                 i, veth_rq_stats_desc[j].desc);
 148
 149                 for (i = 0; i < dev->real_num_tx_queues; i++)
 150                         for (j = 0; j < VETH_TQ_STATS_LEN; j++)
 151                                 ethtool_sprintf(&p, "tx_queue_%u_%.18s",
 152                                                 i, veth_tq_stats_desc[j].desc);
 153                 break;
 154         }
 155 }
 156
 157 static int veth_get_sset_count(struct net_device *dev, int sset)
 158 {
 159         switch (sset) {
 160         case ETH_SS_STATS:
 161                 return ARRAY_SIZE(ethtool_stats_keys) +
 162                        VETH_RQ_STATS_LEN * dev->real_num_rx_queues +
 163                        VETH_TQ_STATS_LEN * dev->real_num_tx_queues;
 164         default:
 165                 return -EOPNOTSUPP;
 166         }
 167 }
 168
 169 static void veth_get_ethtool_stats(struct net_device *dev,
 170                 struct ethtool_stats *stats, u64 *data)
 171 {
 172         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 173         struct net_device *peer = rtnl_dereference(priv->peer);
 174         int i, j, idx;
 175
 176         data[0] = peer ? peer->ifindex : 0;
 177         idx = 1;
 178         for (i = 0; i < dev->real_num_rx_queues; i++) {
 179                 const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
 180                 const void *stats_base = (void *)&rq_stats->vs;
 181                 unsigned int start;
 182                 size_t offset;
 183
 184                 do {
 185                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 186                         for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
 187                                 offset = veth_rq_stats_desc[j].offset;
 188                                 data[idx + j] = *(u64 *)(stats_base + offset);
 189                         }
 190                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 191                 idx += VETH_RQ_STATS_LEN;
 192         }
 193
 194         if (!peer)
 195                 return;
 196
 197         rcv_priv = netdev_priv(peer);
 198         for (i = 0; i < peer->real_num_rx_queues; i++) {
 199                 const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
 200                 const void *base = (void *)&rq_stats->vs;
 201                 unsigned int start, tx_idx = idx;
 202                 size_t offset;
 203
 204                 tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
 205                 do {
 206                         start = u64_stats_fetch_begin_irq(&rq_stats->syncp);
 207                         for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
 208                                 offset = veth_tq_stats_desc[j].offset;
 209                                 data[tx_idx + j] += *(u64 *)(base + offset);
 210                         }
 211                 } while (u64_stats_fetch_retry_irq(&rq_stats->syncp, start));
 212         }
 213 }
 214
 215 static void veth_get_channels(struct net_device *dev,
 216                               struct ethtool_channels *channels)
 217 {
 218         channels->tx_count = dev->real_num_tx_queues;
 219         channels->rx_count = dev->real_num_rx_queues;
 220         channels->max_tx = dev->num_tx_queues;
 221         channels->max_rx = dev->num_rx_queues;
 222 }
 223
 224 static int veth_set_channels(struct net_device *dev,
 225                              struct ethtool_channels *ch);
 226
 227 static const struct ethtool_ops veth_ethtool_ops = {
 228         .get_drvinfo            = veth_get_drvinfo,
 229         .get_link               = ethtool_op_get_link,
 230         .get_strings            = veth_get_strings,
 231         .get_sset_count         = veth_get_sset_count,
 232         .get_ethtool_stats      = veth_get_ethtool_stats,
 233         .get_link_ksettings     = veth_get_link_ksettings,
 234         .get_ts_info            = ethtool_op_get_ts_info,
 235         .get_channels           = veth_get_channels,
 236         .set_channels           = veth_set_channels,
 237 };
 238
 239 /* general routines */
 240
 241 static bool veth_is_xdp_frame(void *ptr)
 242 {
 243         return (unsigned long)ptr & VETH_XDP_FLAG;
 244 }
 245
 246 static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
 247 {
 248         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 249 }
 250
 251 static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
 252 {
 253         return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
 254 }
 255
 256 static void veth_ptr_free(void *ptr)
 257 {
 258         if (veth_is_xdp_frame(ptr))
 259                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 260         else
 261                 kfree_skb(ptr);
 262 }
 263
 264 static void __veth_xdp_flush(struct veth_rq *rq)
 265 {
 266         /* Write ptr_ring before reading rx_notify_masked */
 267         smp_mb();
 268         if (!READ_ONCE(rq->rx_notify_masked) &&
 269             napi_schedule_prep(&rq->xdp_napi)) {
 270                 WRITE_ONCE(rq->rx_notify_masked, true);
 271                 __napi_schedule(&rq->xdp_napi);
 272         }
 273 }
 274
 275 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 276 {
 277         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 278                 dev_kfree_skb_any(skb);
 279                 return NET_RX_DROP;
 280         }
 281
 282         return NET_RX_SUCCESS;
 283 }
 284
 285 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 286                             struct veth_rq *rq, bool xdp)
 287 {
 288         return __dev_forward_skb(dev, skb) ?: xdp ?
 289                 veth_xdp_rx(rq, skb) :
 290                 __netif_rx(skb);
 291 }
 292
 293 /* return true if the specified skb has chances of GRO aggregation
 294  * Don't strive for accuracy, but try to avoid GRO overhead in the most
 295  * common scenarios.
 296  * When XDP is enabled, all traffic is considered eligible, as the xmit
 297  * device has TSO off.
 298  * When TSO is enabled on the xmit device, we are likely interested only
 299  * in UDP aggregation, explicitly check for that if the skb is suspected
 300  * - the sock_wfree destructor is used by UDP, ICMP and XDP sockets -
 301  * to belong to locally generated UDP traffic.
 302  */
 303 static bool veth_skb_is_eligible_for_gro(const struct net_device *dev,
 304                                          const struct net_device *rcv,
 305                                          const struct sk_buff *skb)
 306 {
 307         return !(dev->features & NETIF_F_ALL_TSO) ||
 308                 (skb->destructor == sock_wfree &&
 309                  rcv->features & (NETIF_F_GRO_FRAGLIST | NETIF_F_GRO_UDP_FWD));
 310 }
 311
 312 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 313 {
 314         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 315         struct veth_rq *rq = NULL;
 316         struct net_device *rcv;
 317         int length = skb->len;
 318         bool use_napi = false;
 319         int rxq;
 320
 321         rcu_read_lock();
 322         rcv = rcu_dereference(priv->peer);
 323         if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) {
 324                 kfree_skb(skb);
 325                 goto drop;
 326         }
 327
 328         rcv_priv = netdev_priv(rcv);
 329         rxq = skb_get_queue_mapping(skb);
 330         if (rxq < rcv->real_num_rx_queues) {
 331                 rq = &rcv_priv->rq[rxq];
 332
 333                 /* The napi pointer is available when an XDP program is
 334                  * attached or when GRO is enabled
 335                  * Don't bother with napi/GRO if the skb can't be aggregated
 336                  */
 337                 use_napi = rcu_access_pointer(rq->napi) &&
 338                            veth_skb_is_eligible_for_gro(dev, rcv, skb);
 339         }
 340
 341         skb_tx_timestamp(skb);
 342         if (likely(veth_forward_skb(rcv, skb, rq, use_napi) == NET_RX_SUCCESS)) {
 343                 if (!use_napi)
 344                         dev_lstats_add(dev, length);
 345         } else {
 346 drop:
 347                 atomic64_inc(&priv->dropped);
 348         }
 349
 350         if (use_napi)
 351                 __veth_xdp_flush(rq);
 352
 353         rcu_read_unlock();
 354
 355         return NETDEV_TX_OK;
 356 }
 357
 358 static u64 veth_stats_tx(struct net_device *dev, u64 *packets, u64 *bytes)
 359 {
 360         struct veth_priv *priv = netdev_priv(dev);
 361
 362         dev_lstats_read(dev, packets, bytes);
 363         return atomic64_read(&priv->dropped);
 364 }
 365
 366 static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
 367 {
 368         struct veth_priv *priv = netdev_priv(dev);
 369         int i;
 370
 371         result->peer_tq_xdp_xmit_err = 0;
 372         result->xdp_packets = 0;
 373         result->xdp_tx_err = 0;
 374         result->xdp_bytes = 0;
 375         result->rx_drops = 0;
 376         for (i = 0; i < dev->num_rx_queues; i++) {
 377                 u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
 378                 struct veth_rq_stats *stats = &priv->rq[i].stats;
 379                 unsigned int start;
 380
 381                 do {
 382                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 383                         peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
 384                         xdp_tx_err = stats->vs.xdp_tx_err;
 385                         packets = stats->vs.xdp_packets;
 386                         bytes = stats->vs.xdp_bytes;
 387                         drops = stats->vs.rx_drops;
 388                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 389                 result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
 390                 result->xdp_tx_err += xdp_tx_err;
 391                 result->xdp_packets += packets;
 392                 result->xdp_bytes += bytes;
 393                 result->rx_drops += drops;
 394         }
 395 }
 396
 397 static void veth_get_stats64(struct net_device *dev,
 398                              struct rtnl_link_stats64 *tot)
 399 {
 400         struct veth_priv *priv = netdev_priv(dev);
 401         struct net_device *peer;
 402         struct veth_stats rx;
 403         u64 packets, bytes;
 404
 405         tot->tx_dropped = veth_stats_tx(dev, &packets, &bytes);
 406         tot->tx_bytes = bytes;
 407         tot->tx_packets = packets;
 408
 409         veth_stats_rx(&rx, dev);
 410         tot->tx_dropped += rx.xdp_tx_err;
 411         tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
 412         tot->rx_bytes = rx.xdp_bytes;
 413         tot->rx_packets = rx.xdp_packets;
 414
 415         rcu_read_lock();
 416         peer = rcu_dereference(priv->peer);
 417         if (peer) {
 418                 veth_stats_tx(peer, &packets, &bytes);
 419                 tot->rx_bytes += bytes;
 420                 tot->rx_packets += packets;
 421
 422                 veth_stats_rx(&rx, peer);
 423                 tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
 424                 tot->rx_dropped += rx.xdp_tx_err;
 425                 tot->tx_bytes += rx.xdp_bytes;
 426                 tot->tx_packets += rx.xdp_packets;
 427         }
 428         rcu_read_unlock();
 429 }
 430
 431 /* fake multicast ability */
 432 static void veth_set_multicast_list(struct net_device *dev)
 433 {
 434 }
 435
 436 static int veth_select_rxq(struct net_device *dev)
 437 {
 438         return smp_processor_id() % dev->real_num_rx_queues;
 439 }
 440
 441 static struct net_device *veth_peer_dev(struct net_device *dev)
 442 {
 443         struct veth_priv *priv = netdev_priv(dev);
 444
 445         /* Callers must be under RCU read side. */
 446         return rcu_dereference(priv->peer);
 447 }
 448
 449 static int veth_xdp_xmit(struct net_device *dev, int n,
 450                          struct xdp_frame **frames,
 451                          u32 flags, bool ndo_xmit)
 452 {
 453         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 454         int i, ret = -ENXIO, nxmit = 0;
 455         struct net_device *rcv;
 456         unsigned int max_len;
 457         struct veth_rq *rq;
 458
 459         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
 460                 return -EINVAL;
 461
 462         rcu_read_lock();
 463         rcv = rcu_dereference(priv->peer);
 464         if (unlikely(!rcv))
 465                 goto out;
 466
 467         rcv_priv = netdev_priv(rcv);
 468         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 469         /* The napi pointer is set if NAPI is enabled, which ensures that
 470          * xdp_ring is initialized on receive side and the peer device is up.
 471          */
 472         if (!rcu_access_pointer(rq->napi))
 473                 goto out;
 474
 475         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 476
 477         spin_lock(&rq->xdp_ring.producer_lock);
 478         for (i = 0; i < n; i++) {
 479                 struct xdp_frame *frame = frames[i];
 480                 void *ptr = veth_xdp_to_ptr(frame);
 481
 482                 if (unlikely(xdp_get_frame_len(frame) > max_len ||
 483                              __ptr_ring_produce(&rq->xdp_ring, ptr)))
 484                         break;
 485                 nxmit++;
 486         }
 487         spin_unlock(&rq->xdp_ring.producer_lock);
 488
 489         if (flags & XDP_XMIT_FLUSH)
 490                 __veth_xdp_flush(rq);
 491
 492         ret = nxmit;
 493         if (ndo_xmit) {
 494                 u64_stats_update_begin(&rq->stats.syncp);
 495                 rq->stats.vs.peer_tq_xdp_xmit += nxmit;
 496                 rq->stats.vs.peer_tq_xdp_xmit_err += n - nxmit;
 497                 u64_stats_update_end(&rq->stats.syncp);
 498         }
 499
 500 out:
 501         rcu_read_unlock();
 502
 503         return ret;
 504 }
 505
 506 static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
 507                              struct xdp_frame **frames, u32 flags)
 508 {
 509         int err;
 510
 511         err = veth_xdp_xmit(dev, n, frames, flags, true);
 512         if (err < 0) {
 513                 struct veth_priv *priv = netdev_priv(dev);
 514
 515                 atomic64_add(n, &priv->dropped);
 516         }
 517
 518         return err;
 519 }
 520
 521 static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
 522 {
 523         int sent, i, err = 0, drops;
 524
 525         sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
 526         if (sent < 0) {
 527                 err = sent;
 528                 sent = 0;
 529         }
 530
 531         for (i = sent; unlikely(i < bq->count); i++)
 532                 xdp_return_frame(bq->q[i]);
 533
 534         drops = bq->count - sent;
 535         trace_xdp_bulk_tx(rq->dev, sent, drops, err);
 536
 537         u64_stats_update_begin(&rq->stats.syncp);
 538         rq->stats.vs.xdp_tx += sent;
 539         rq->stats.vs.xdp_tx_err += drops;
 540         u64_stats_update_end(&rq->stats.syncp);
 541
 542         bq->count = 0;
 543 }
 544
 545 static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
 546 {
 547         struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
 548         struct net_device *rcv;
 549         struct veth_rq *rcv_rq;
 550
 551         rcu_read_lock();
 552         veth_xdp_flush_bq(rq, bq);
 553         rcv = rcu_dereference(priv->peer);
 554         if (unlikely(!rcv))
 555                 goto out;
 556
 557         rcv_priv = netdev_priv(rcv);
 558         rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 559         /* xdp_ring is initialized on receive side? */
 560         if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
 561                 goto out;
 562
 563         __veth_xdp_flush(rcv_rq);
 564 out:
 565         rcu_read_unlock();
 566 }
 567
 568 static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
 569                        struct veth_xdp_tx_bq *bq)
 570 {
 571         struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
 572
 573         if (unlikely(!frame))
 574                 return -EOVERFLOW;
 575
 576         if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
 577                 veth_xdp_flush_bq(rq, bq);
 578
 579         bq->q[bq->count++] = frame;
 580
 581         return 0;
 582 }
 583
 584 static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
 585                                           struct xdp_frame *frame,
 586                                           struct veth_xdp_tx_bq *bq,
 587                                           struct veth_stats *stats)
 588 {
 589         struct xdp_frame orig_frame;
 590         struct bpf_prog *xdp_prog;
 591
 592         rcu_read_lock();
 593         xdp_prog = rcu_dereference(rq->xdp_prog);
 594         if (likely(xdp_prog)) {
 595                 struct xdp_buff xdp;
 596                 u32 act;
 597
 598                 xdp_convert_frame_to_buff(frame, &xdp);
 599                 xdp.rxq = &rq->xdp_rxq;
 600
 601                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 602
 603                 switch (act) {
 604                 case XDP_PASS:
 605                         if (xdp_update_frame_from_buff(&xdp, frame))
 606                                 goto err_xdp;
 607                         break;
 608                 case XDP_TX:
 609                         orig_frame = *frame;
 610                         xdp.rxq->mem = frame->mem;
 611                         if (unlikely(veth_xdp_tx(rq, &xdp, bq) < 0)) {
 612                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 613                                 frame = &orig_frame;
 614                                 stats->rx_drops++;
 615                                 goto err_xdp;
 616                         }
 617                         stats->xdp_tx++;
 618                         rcu_read_unlock();
 619                         goto xdp_xmit;
 620                 case XDP_REDIRECT:
 621                         orig_frame = *frame;
 622                         xdp.rxq->mem = frame->mem;
 623                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 624                                 frame = &orig_frame;
 625                                 stats->rx_drops++;
 626                                 goto err_xdp;
 627                         }
 628                         stats->xdp_redirect++;
 629                         rcu_read_unlock();
 630                         goto xdp_xmit;
 631                 default:
 632                         bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
 633                         fallthrough;
 634                 case XDP_ABORTED:
 635                         trace_xdp_exception(rq->dev, xdp_prog, act);
 636                         fallthrough;
 637                 case XDP_DROP:
 638                         stats->xdp_drops++;
 639                         goto err_xdp;
 640                 }
 641         }
 642         rcu_read_unlock();
 643
 644         return frame;
 645 err_xdp:
 646         rcu_read_unlock();
 647         xdp_return_frame(frame);
 648 xdp_xmit:
 649         return NULL;
 650 }
 651
 652 /* frames array contains VETH_XDP_BATCH at most */
 653 static void veth_xdp_rcv_bulk_skb(struct veth_rq *rq, void **frames,
 654                                   int n_xdpf, struct veth_xdp_tx_bq *bq,
 655                                   struct veth_stats *stats)
 656 {
 657         void *skbs[VETH_XDP_BATCH];
 658         int i;
 659
 660         if (xdp_alloc_skb_bulk(skbs, n_xdpf,
 661                                GFP_ATOMIC | __GFP_ZERO) < 0) {
 662                 for (i = 0; i < n_xdpf; i++)
 663                         xdp_return_frame(frames[i]);
 664                 stats->rx_drops += n_xdpf;
 665
 666                 return;
 667         }
 668
 669         for (i = 0; i < n_xdpf; i++) {
 670                 struct sk_buff *skb = skbs[i];
 671
 672                 skb = __xdp_build_skb_from_frame(frames[i], skb,
 673                                                  rq->dev);
 674                 if (!skb) {
 675                         xdp_return_frame(frames[i]);
 676                         stats->rx_drops++;
 677                         continue;
 678                 }
 679                 napi_gro_receive(&rq->xdp_napi, skb);
 680         }
 681 }
 682
 683 static void veth_xdp_get(struct xdp_buff *xdp)
 684 {
 685         struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
 686         int i;
 687
 688         get_page(virt_to_page(xdp->data));
 689         if (likely(!xdp_buff_has_frags(xdp)))
 690                 return;
 691
 692         for (i = 0; i < sinfo->nr_frags; i++)
 693                 __skb_frag_ref(&sinfo->frags[i]);
 694 }
 695
 696 static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
 697                                         struct xdp_buff *xdp,
 698                                         struct sk_buff **pskb)
 699 {
 700         struct sk_buff *skb = *pskb;
 701         u32 frame_sz;
 702
 703         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 704             skb_shinfo(skb)->nr_frags) {
 705                 u32 size, len, max_head_size, off;
 706                 struct sk_buff *nskb;
 707                 struct page *page;
 708                 int i, head_off;
 709
 710                 /* We need a private copy of the skb and data buffers since
 711                  * the ebpf program can modify it. We segment the original skb
 712                  * into order-0 pages without linearize it.
 713                  *
 714                  * Make sure we have enough space for linear and paged area
 715                  */
 716                 max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE -
 717                                                   VETH_XDP_HEADROOM);
 718                 if (skb->len > PAGE_SIZE * MAX_SKB_FRAGS + max_head_size)
 719                         goto drop;
 720
 721                 /* Allocate skb head */
 722                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 723                 if (!page)
 724                         goto drop;
 725
 726                 nskb = build_skb(page_address(page), PAGE_SIZE);
 727                 if (!nskb) {
 728                         put_page(page);
 729                         goto drop;
 730                 }
 731
 732                 skb_reserve(nskb, VETH_XDP_HEADROOM);
 733                 size = min_t(u32, skb->len, max_head_size);
 734                 if (skb_copy_bits(skb, 0, nskb->data, size)) {
 735                         consume_skb(nskb);
 736                         goto drop;
 737                 }
 738                 skb_put(nskb, size);
 739
 740                 skb_copy_header(nskb, skb);
 741                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 742                 skb_headers_offset_update(nskb, head_off);
 743
 744                 /* Allocate paged area of new skb */
 745                 off = size;
 746                 len = skb->len - off;
 747
 748                 for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
 749                         page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 750                         if (!page) {
 751                                 consume_skb(nskb);
 752                                 goto drop;
 753                         }
 754
 755                         size = min_t(u32, len, PAGE_SIZE);
 756                         skb_add_rx_frag(nskb, i, page, 0, size, PAGE_SIZE);
 757                         if (skb_copy_bits(skb, off, page_address(page),
 758                                           size)) {
 759                                 consume_skb(nskb);
 760                                 goto drop;
 761                         }
 762
 763                         len -= size;
 764                         off += size;
 765                 }
 766
 767                 consume_skb(skb);
 768                 skb = nskb;
 769         } else if (skb_headroom(skb) < XDP_PACKET_HEADROOM &&
 770                    pskb_expand_head(skb, VETH_XDP_HEADROOM, 0, GFP_ATOMIC)) {
 771                 goto drop;
 772         }
 773
 774         /* SKB "head" area always have tailroom for skb_shared_info */
 775         frame_sz = skb_end_pointer(skb) - skb->head;
 776         frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 777         xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
 778         xdp_prepare_buff(xdp, skb->head, skb_headroom(skb),
 779                          skb_headlen(skb), true);
 780
 781         if (skb_is_nonlinear(skb)) {
 782                 skb_shinfo(skb)->xdp_frags_size = skb->data_len;
 783                 xdp_buff_set_frags_flag(xdp);
 784         } else {
 785                 xdp_buff_clear_frags_flag(xdp);
 786         }
 787         *pskb = skb;
 788
 789         return 0;
 790 drop:
 791         consume_skb(skb);
 792         *pskb = NULL;
 793
 794         return -ENOMEM;
 795 }
 796
 797 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
 798                                         struct sk_buff *skb,
 799                                         struct veth_xdp_tx_bq *bq,
 800                                         struct veth_stats *stats)
 801 {
 802         void *orig_data, *orig_data_end;
 803         struct bpf_prog *xdp_prog;
 804         struct xdp_buff xdp;
 805         u32 act, metalen;
 806         int off;
 807
 808         skb_prepare_for_gro(skb);
 809
 810         rcu_read_lock();
 811         xdp_prog = rcu_dereference(rq->xdp_prog);
 812         if (unlikely(!xdp_prog)) {
 813                 rcu_read_unlock();
 814                 goto out;
 815         }
 816
 817         __skb_push(skb, skb->data - skb_mac_header(skb));
 818         if (veth_convert_skb_to_xdp_buff(rq, &xdp, &skb))
 819                 goto drop;
 820
 821         orig_data = xdp.data;
 822         orig_data_end = xdp.data_end;
 823
 824         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 825
 826         switch (act) {
 827         case XDP_PASS:
 828                 break;
 829         case XDP_TX:
 830                 veth_xdp_get(&xdp);
 831                 consume_skb(skb);
 832                 xdp.rxq->mem = rq->xdp_mem;
 833                 if (unlikely(veth_xdp_tx(rq, &xdp, bq) < 0)) {
 834                         trace_xdp_exception(rq->dev, xdp_prog, act);
 835                         stats->rx_drops++;
 836                         goto err_xdp;
 837                 }
 838                 stats->xdp_tx++;
 839                 rcu_read_unlock();
 840                 goto xdp_xmit;
 841         case XDP_REDIRECT:
 842                 veth_xdp_get(&xdp);
 843                 consume_skb(skb);
 844                 xdp.rxq->mem = rq->xdp_mem;
 845                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 846                         stats->rx_drops++;
 847                         goto err_xdp;
 848                 }
 849                 stats->xdp_redirect++;
 850                 rcu_read_unlock();
 851                 goto xdp_xmit;
 852         default:
 853                 bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
 854                 fallthrough;
 855         case XDP_ABORTED:
 856                 trace_xdp_exception(rq->dev, xdp_prog, act);
 857                 fallthrough;
 858         case XDP_DROP:
 859                 stats->xdp_drops++;
 860                 goto xdp_drop;
 861         }
 862         rcu_read_unlock();
 863
 864         /* check if bpf_xdp_adjust_head was used */
 865         off = orig_data - xdp.data;
 866         if (off > 0)
 867                 __skb_push(skb, off);
 868         else if (off < 0)
 869                 __skb_pull(skb, -off);
 870
 871         skb_reset_mac_header(skb);
 872
 873         /* check if bpf_xdp_adjust_tail was used */
 874         off = xdp.data_end - orig_data_end;
 875         if (off != 0)
 876                 __skb_put(skb, off); /* positive on grow, negative on shrink */
 877
 878         /* XDP frag metadata (e.g. nr_frags) are updated in eBPF helpers
 879          * (e.g. bpf_xdp_adjust_tail), we need to update data_len here.
 880          */
 881         if (xdp_buff_has_frags(&xdp))
 882                 skb->data_len = skb_shinfo(skb)->xdp_frags_size;
 883         else
 884                 skb->data_len = 0;
 885
 886         skb->protocol = eth_type_trans(skb, rq->dev);
 887
 888         metalen = xdp.data - xdp.data_meta;
 889         if (metalen)
 890                 skb_metadata_set(skb, metalen);
 891 out:
 892         return skb;
 893 drop:
 894         stats->rx_drops++;
 895 xdp_drop:
 896         rcu_read_unlock();
 897         kfree_skb(skb);
 898         return NULL;
 899 err_xdp:
 900         rcu_read_unlock();
 901         xdp_return_buff(&xdp);
 902 xdp_xmit:
 903         return NULL;
 904 }
 905
 906 static int veth_xdp_rcv(struct veth_rq *rq, int budget,
 907                         struct veth_xdp_tx_bq *bq,
 908                         struct veth_stats *stats)
 909 {
 910         int i, done = 0, n_xdpf = 0;
 911         void *xdpf[VETH_XDP_BATCH];
 912
 913         for (i = 0; i < budget; i++) {
 914                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 915
 916                 if (!ptr)
 917                         break;
 918
 919                 if (veth_is_xdp_frame(ptr)) {
 920                         /* ndo_xdp_xmit */
 921                         struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
 922
 923                         stats->xdp_bytes += xdp_get_frame_len(frame);
 924                         frame = veth_xdp_rcv_one(rq, frame, bq, stats);
 925                         if (frame) {
 926                                 /* XDP_PASS */
 927                                 xdpf[n_xdpf++] = frame;
 928                                 if (n_xdpf == VETH_XDP_BATCH) {
 929                                         veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf,
 930                                                               bq, stats);
 931                                         n_xdpf = 0;
 932                                 }
 933                         }
 934                 } else {
 935                         /* ndo_start_xmit */
 936                         struct sk_buff *skb = ptr;
 937
 938                         stats->xdp_bytes += skb->len;
 939                         skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
 940                         if (skb) {
 941                                 if (skb_shared(skb) || skb_unclone(skb, GFP_ATOMIC))
 942                                         netif_receive_skb(skb);
 943                                 else
 944                                         napi_gro_receive(&rq->xdp_napi, skb);
 945                         }
 946                 }
 947                 done++;
 948         }
 949
 950         if (n_xdpf)
 951                 veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf, bq, stats);
 952
 953         u64_stats_update_begin(&rq->stats.syncp);
 954         rq->stats.vs.xdp_redirect += stats->xdp_redirect;
 955         rq->stats.vs.xdp_bytes += stats->xdp_bytes;
 956         rq->stats.vs.xdp_drops += stats->xdp_drops;
 957         rq->stats.vs.rx_drops += stats->rx_drops;
 958         rq->stats.vs.xdp_packets += done;
 959         u64_stats_update_end(&rq->stats.syncp);
 960
 961         return done;
 962 }
 963
 964 static int veth_poll(struct napi_struct *napi, int budget)
 965 {
 966         struct veth_rq *rq =
 967                 container_of(napi, struct veth_rq, xdp_napi);
 968         struct veth_stats stats = {};
 969         struct veth_xdp_tx_bq bq;
 970         int done;
 971
 972         bq.count = 0;
 973
 974         xdp_set_return_frame_no_direct();
 975         done = veth_xdp_rcv(rq, budget, &bq, &stats);
 976
 977         if (stats.xdp_redirect > 0)
 978                 xdp_do_flush();
 979
 980         if (done < budget && napi_complete_done(napi, done)) {
 981                 /* Write rx_notify_masked before reading ptr_ring */
 982                 smp_store_mb(rq->rx_notify_masked, false);
 983                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 984                         if (napi_schedule_prep(&rq->xdp_napi)) {
 985                                 WRITE_ONCE(rq->rx_notify_masked, true);
 986                                 __napi_schedule(&rq->xdp_napi);
 987                         }
 988                 }
 989         }
 990
 991         if (stats.xdp_tx > 0)
 992                 veth_xdp_flush(rq, &bq);
 993         xdp_clear_return_frame_no_direct();
 994
 995         return done;
 996 }
 997
 998 static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
 999 {
1000         struct veth_priv *priv = netdev_priv(dev);
1001         int err, i;
1002
1003         for (i = start; i < end; i++) {
1004                 struct veth_rq *rq = &priv->rq[i];
1005
1006                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
1007                 if (err)
1008                         goto err_xdp_ring;
1009         }
1010
1011         for (i = start; i < end; i++) {
1012                 struct veth_rq *rq = &priv->rq[i];
1013
1014                 napi_enable(&rq->xdp_napi);
1015                 rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1016         }
1017
1018         return 0;
1019
1020 err_xdp_ring:
1021         for (i--; i >= start; i--)
1022                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
1023
1024         return err;
1025 }
1026
1027 static int __veth_napi_enable(struct net_device *dev)
1028 {
1029         return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1030 }
1031
1032 static void veth_napi_del_range(struct net_device *dev, int start, int end)
1033 {
1034         struct veth_priv *priv = netdev_priv(dev);
1035         int i;
1036
1037         for (i = start; i < end; i++) {
1038                 struct veth_rq *rq = &priv->rq[i];
1039
1040                 rcu_assign_pointer(priv->rq[i].napi, NULL);
1041                 napi_disable(&rq->xdp_napi);
1042                 __netif_napi_del(&rq->xdp_napi);
1043         }
1044         synchronize_net();
1045
1046         for (i = start; i < end; i++) {
1047                 struct veth_rq *rq = &priv->rq[i];
1048
1049                 rq->rx_notify_masked = false;
1050                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
1051         }
1052 }
1053
1054 static void veth_napi_del(struct net_device *dev)
1055 {
1056         veth_napi_del_range(dev, 0, dev->real_num_rx_queues);
1057 }
1058
1059 static bool veth_gro_requested(const struct net_device *dev)
1060 {
1061         return !!(dev->wanted_features & NETIF_F_GRO);
1062 }
1063
1064 static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
1065                                  bool napi_already_on)
1066 {
1067         struct veth_priv *priv = netdev_priv(dev);
1068         int err, i;
1069
1070         for (i = start; i < end; i++) {
1071                 struct veth_rq *rq = &priv->rq[i];
1072
1073                 if (!napi_already_on)
1074                         netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1075                 err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
1076                 if (err < 0)
1077                         goto err_rxq_reg;
1078
1079                 err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
1080                                                  MEM_TYPE_PAGE_SHARED,
1081                                                  NULL);
1082                 if (err < 0)
1083                         goto err_reg_mem;
1084
1085                 /* Save original mem info as it can be overwritten */
1086                 rq->xdp_mem = rq->xdp_rxq.mem;
1087         }
1088         return 0;
1089
1090 err_reg_mem:
1091         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
1092 err_rxq_reg:
1093         for (i--; i >= start; i--) {
1094                 struct veth_rq *rq = &priv->rq[i];
1095
1096                 xdp_rxq_info_unreg(&rq->xdp_rxq);
1097                 if (!napi_already_on)
1098                         netif_napi_del(&rq->xdp_napi);
1099         }
1100
1101         return err;
1102 }
1103
1104 static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
1105                                    bool delete_napi)
1106 {
1107         struct veth_priv *priv = netdev_priv(dev);
1108         int i;
1109
1110         for (i = start; i < end; i++) {
1111                 struct veth_rq *rq = &priv->rq[i];
1112
1113                 rq->xdp_rxq.mem = rq->xdp_mem;
1114                 xdp_rxq_info_unreg(&rq->xdp_rxq);
1115
1116                 if (delete_napi)
1117                         netif_napi_del(&rq->xdp_napi);
1118         }
1119 }
1120
1121 static int veth_enable_xdp(struct net_device *dev)
1122 {
1123         bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP);
1124         struct veth_priv *priv = netdev_priv(dev);
1125         int err, i;
1126
1127         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
1128                 err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
1129                 if (err)
1130                         return err;
1131
1132                 if (!napi_already_on) {
1133                         err = __veth_napi_enable(dev);
1134                         if (err) {
1135                                 veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
1136                                 return err;
1137                         }
1138
1139                         if (!veth_gro_requested(dev)) {
1140                                 /* user-space did not require GRO, but adding XDP
1141                                  * is supposed to get GRO working
1142                                  */
1143                                 dev->features |= NETIF_F_GRO;
1144                                 netdev_features_change(dev);
1145                         }
1146                 }
1147         }
1148
1149         for (i = 0; i < dev->real_num_rx_queues; i++) {
1150                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
1151                 rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1152         }
1153
1154         return 0;
1155 }
1156
1157 static void veth_disable_xdp(struct net_device *dev)
1158 {
1159         struct veth_priv *priv = netdev_priv(dev);
1160         int i;
1161
1162         for (i = 0; i < dev->real_num_rx_queues; i++)
1163                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
1164
1165         if (!netif_running(dev) || !veth_gro_requested(dev)) {
1166                 veth_napi_del(dev);
1167
1168                 /* if user-space did not require GRO, since adding XDP
1169                  * enabled it, clear it now
1170                  */
1171                 if (!veth_gro_requested(dev) && netif_running(dev)) {
1172                         dev->features &= ~NETIF_F_GRO;
1173                         netdev_features_change(dev);
1174                 }
1175         }
1176
1177         veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
1178 }
1179
1180 static int veth_napi_enable_range(struct net_device *dev, int start, int end)
1181 {
1182         struct veth_priv *priv = netdev_priv(dev);
1183         int err, i;
1184
1185         for (i = start; i < end; i++) {
1186                 struct veth_rq *rq = &priv->rq[i];
1187
1188                 netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1189         }
1190
1191         err = __veth_napi_enable_range(dev, start, end);
1192         if (err) {
1193                 for (i = start; i < end; i++) {
1194                         struct veth_rq *rq = &priv->rq[i];
1195
1196                         netif_napi_del(&rq->xdp_napi);
1197                 }
1198                 return err;
1199         }
1200         return err;
1201 }
1202
1203 static int veth_napi_enable(struct net_device *dev)
1204 {
1205         return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1206 }
1207
1208 static void veth_disable_range_safe(struct net_device *dev, int start, int end)
1209 {
1210         struct veth_priv *priv = netdev_priv(dev);
1211
1212         if (start >= end)
1213                 return;
1214
1215         if (priv->_xdp_prog) {
1216                 veth_napi_del_range(dev, start, end);
1217                 veth_disable_xdp_range(dev, start, end, false);
1218         } else if (veth_gro_requested(dev)) {
1219                 veth_napi_del_range(dev, start, end);
1220         }
1221 }
1222
1223 static int veth_enable_range_safe(struct net_device *dev, int start, int end)
1224 {
1225         struct veth_priv *priv = netdev_priv(dev);
1226         int err;
1227
1228         if (start >= end)
1229                 return 0;
1230
1231         if (priv->_xdp_prog) {
1232                 /* these channels are freshly initialized, napi is not on there even
1233                  * when GRO is requeste
1234                  */
1235                 err = veth_enable_xdp_range(dev, start, end, false);
1236                 if (err)
1237                         return err;
1238
1239                 err = __veth_napi_enable_range(dev, start, end);
1240                 if (err) {
1241                         /* on error always delete the newly added napis */
1242                         veth_disable_xdp_range(dev, start, end, true);
1243                         return err;
1244                 }
1245         } else if (veth_gro_requested(dev)) {
1246                 return veth_napi_enable_range(dev, start, end);
1247         }
1248         return 0;
1249 }
1250
1251 static int veth_set_channels(struct net_device *dev,
1252                              struct ethtool_channels *ch)
1253 {
1254         struct veth_priv *priv = netdev_priv(dev);
1255         unsigned int old_rx_count, new_rx_count;
1256         struct veth_priv *peer_priv;
1257         struct net_device *peer;
1258         int err;
1259
1260         /* sanity check. Upper bounds are already enforced by the caller */
1261         if (!ch->rx_count || !ch->tx_count)
1262                 return -EINVAL;
1263
1264         /* avoid braking XDP, if that is enabled */
1265         peer = rtnl_dereference(priv->peer);
1266         peer_priv = peer ? netdev_priv(peer) : NULL;
1267         if (priv->_xdp_prog && peer && ch->rx_count < peer->real_num_tx_queues)
1268                 return -EINVAL;
1269
1270         if (peer && peer_priv && peer_priv->_xdp_prog && ch->tx_count > peer->real_num_rx_queues)
1271                 return -EINVAL;
1272
1273         old_rx_count = dev->real_num_rx_queues;
1274         new_rx_count = ch->rx_count;
1275         if (netif_running(dev)) {
1276                 /* turn device off */
1277                 netif_carrier_off(dev);
1278                 if (peer)
1279                         netif_carrier_off(peer);
1280
1281                 /* try to allocate new resurces, as needed*/
1282                 err = veth_enable_range_safe(dev, old_rx_count, new_rx_count);
1283                 if (err)
1284                         goto out;
1285         }
1286
1287         err = netif_set_real_num_rx_queues(dev, ch->rx_count);
1288         if (err)
1289                 goto revert;
1290
1291         err = netif_set_real_num_tx_queues(dev, ch->tx_count);
1292         if (err) {
1293                 int err2 = netif_set_real_num_rx_queues(dev, old_rx_count);
1294
1295                 /* this error condition could happen only if rx and tx change
1296                  * in opposite directions (e.g. tx nr raises, rx nr decreases)
1297                  * and we can't do anything to fully restore the original
1298                  * status
1299                  */
1300                 if (err2)
1301                         pr_warn("Can't restore rx queues config %d -> %d %d",
1302                                 new_rx_count, old_rx_count, err2);
1303                 else
1304                         goto revert;
1305         }
1306
1307 out:
1308         if (netif_running(dev)) {
1309                 /* note that we need to swap the arguments WRT the enable part
1310                  * to identify the range we have to disable
1311                  */
1312                 veth_disable_range_safe(dev, new_rx_count, old_rx_count);
1313                 netif_carrier_on(dev);
1314                 if (peer)
1315                         netif_carrier_on(peer);
1316         }
1317         return err;
1318
1319 revert:
1320         new_rx_count = old_rx_count;
1321         old_rx_count = ch->rx_count;
1322         goto out;
1323 }
1324
1325 static int veth_open(struct net_device *dev)
1326 {
1327         struct veth_priv *priv = netdev_priv(dev);
1328         struct net_device *peer = rtnl_dereference(priv->peer);
1329         int err;
1330
1331         if (!peer)
1332                 return -ENOTCONN;
1333
1334         if (priv->_xdp_prog) {
1335                 err = veth_enable_xdp(dev);
1336                 if (err)
1337                         return err;
1338         } else if (veth_gro_requested(dev)) {
1339                 err = veth_napi_enable(dev);
1340                 if (err)
1341                         return err;
1342         }
1343
1344         if (peer->flags & IFF_UP) {
1345                 netif_carrier_on(dev);
1346                 netif_carrier_on(peer);
1347         }
1348
1349         return 0;
1350 }
1351
1352 static int veth_close(struct net_device *dev)
1353 {
1354         struct veth_priv *priv = netdev_priv(dev);
1355         struct net_device *peer = rtnl_dereference(priv->peer);
1356
1357         netif_carrier_off(dev);
1358         if (peer)
1359                 netif_carrier_off(peer);
1360
1361         if (priv->_xdp_prog)
1362                 veth_disable_xdp(dev);
1363         else if (veth_gro_requested(dev))
1364                 veth_napi_del(dev);
1365
1366         return 0;
1367 }
1368
1369 static int is_valid_veth_mtu(int mtu)
1370 {
1371         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
1372 }
1373
1374 static int veth_alloc_queues(struct net_device *dev)
1375 {
1376         struct veth_priv *priv = netdev_priv(dev);
1377         int i;
1378
1379         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL_ACCOUNT);
1380         if (!priv->rq)
1381                 return -ENOMEM;
1382
1383         for (i = 0; i < dev->num_rx_queues; i++) {
1384                 priv->rq[i].dev = dev;
1385                 u64_stats_init(&priv->rq[i].stats.syncp);
1386         }
1387
1388         return 0;
1389 }
1390
1391 static void veth_free_queues(struct net_device *dev)
1392 {
1393         struct veth_priv *priv = netdev_priv(dev);
1394
1395         kfree(priv->rq);
1396 }
1397
1398 static int veth_dev_init(struct net_device *dev)
1399 {
1400         int err;
1401
1402         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
1403         if (!dev->lstats)
1404                 return -ENOMEM;
1405
1406         err = veth_alloc_queues(dev);
1407         if (err) {
1408                 free_percpu(dev->lstats);
1409                 return err;
1410         }
1411
1412         return 0;
1413 }
1414
1415 static void veth_dev_free(struct net_device *dev)
1416 {
1417         veth_free_queues(dev);
1418         free_percpu(dev->lstats);
1419 }
1420
1421 #ifdef CONFIG_NET_POLL_CONTROLLER
1422 static void veth_poll_controller(struct net_device *dev)
1423 {
1424         /* veth only receives frames when its peer sends one
1425          * Since it has nothing to do with disabling irqs, we are guaranteed
1426          * never to have pending data when we poll for it so
1427          * there is nothing to do here.
1428          *
1429          * We need this though so netpoll recognizes us as an interface that
1430          * supports polling, which enables bridge devices in virt setups to
1431          * still use netconsole
1432          */
1433 }
1434 #endif  /* CONFIG_NET_POLL_CONTROLLER */
1435
1436 static int veth_get_iflink(const struct net_device *dev)
1437 {
1438         struct veth_priv *priv = netdev_priv(dev);
1439         struct net_device *peer;
1440         int iflink;
1441
1442         rcu_read_lock();
1443         peer = rcu_dereference(priv->peer);
1444         iflink = peer ? peer->ifindex : 0;
1445         rcu_read_unlock();
1446
1447         return iflink;
1448 }
1449
1450 static netdev_features_t veth_fix_features(struct net_device *dev,
1451                                            netdev_features_t features)
1452 {
1453         struct veth_priv *priv = netdev_priv(dev);
1454         struct net_device *peer;
1455
1456         peer = rtnl_dereference(priv->peer);
1457         if (peer) {
1458                 struct veth_priv *peer_priv = netdev_priv(peer);
1459
1460                 if (peer_priv->_xdp_prog)
1461                         features &= ~NETIF_F_GSO_SOFTWARE;
1462         }
1463         if (priv->_xdp_prog)
1464                 features |= NETIF_F_GRO;
1465
1466         return features;
1467 }
1468
1469 static int veth_set_features(struct net_device *dev,
1470                              netdev_features_t features)
1471 {
1472         netdev_features_t changed = features ^ dev->features;
1473         struct veth_priv *priv = netdev_priv(dev);
1474         int err;
1475
1476         if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
1477                 return 0;
1478
1479         if (features & NETIF_F_GRO) {
1480                 err = veth_napi_enable(dev);
1481                 if (err)
1482                         return err;
1483         } else {
1484                 veth_napi_del(dev);
1485         }
1486         return 0;
1487 }
1488
1489 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1490 {
1491         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1492         struct net_device *peer;
1493
1494         if (new_hr < 0)
1495                 new_hr = 0;
1496
1497         rcu_read_lock();
1498         peer = rcu_dereference(priv->peer);
1499         if (unlikely(!peer))
1500                 goto out;
1501
1502         peer_priv = netdev_priv(peer);
1503         priv->requested_headroom = new_hr;
1504         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1505         dev->needed_headroom = new_hr;
1506         peer->needed_headroom = new_hr;
1507
1508 out:
1509         rcu_read_unlock();
1510 }
1511
1512 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1513                         struct netlink_ext_ack *extack)
1514 {
1515         struct veth_priv *priv = netdev_priv(dev);
1516         struct bpf_prog *old_prog;
1517         struct net_device *peer;
1518         unsigned int max_mtu;
1519         int err;
1520
1521         old_prog = priv->_xdp_prog;
1522         priv->_xdp_prog = prog;
1523         peer = rtnl_dereference(priv->peer);
1524
1525         if (prog) {
1526                 if (!peer) {
1527                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1528                         err = -ENOTCONN;
1529                         goto err;
1530                 }
1531
1532                 max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
1533                           peer->hard_header_len;
1534                 /* Allow increasing the max_mtu if the program supports
1535                  * XDP fragments.
1536                  */
1537                 if (prog->aux->xdp_has_frags)
1538                         max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;
1539
1540                 if (peer->mtu > max_mtu) {
1541                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1542                         err = -ERANGE;
1543                         goto err;
1544                 }
1545
1546                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1547                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1548                         err = -ENOSPC;
1549                         goto err;
1550                 }
1551
1552                 if (dev->flags & IFF_UP) {
1553                         err = veth_enable_xdp(dev);
1554                         if (err) {
1555                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1556                                 goto err;
1557                         }
1558                 }
1559
1560                 if (!old_prog) {
1561                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1562                         peer->max_mtu = max_mtu;
1563                 }
1564         }
1565
1566         if (old_prog) {
1567                 if (!prog) {
1568                         if (dev->flags & IFF_UP)
1569                                 veth_disable_xdp(dev);
1570
1571                         if (peer) {
1572                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1573                                 peer->max_mtu = ETH_MAX_MTU;
1574                         }
1575                 }
1576                 bpf_prog_put(old_prog);
1577         }
1578
1579         if ((!!old_prog ^ !!prog) && peer)
1580                 netdev_update_features(peer);
1581
1582         return 0;
1583 err:
1584         priv->_xdp_prog = old_prog;
1585
1586         return err;
1587 }
1588
1589 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1590 {
1591         switch (xdp->command) {
1592         case XDP_SETUP_PROG:
1593                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1594         default:
1595                 return -EINVAL;
1596         }
1597 }
1598
1599 static const struct net_device_ops veth_netdev_ops = {
1600         .ndo_init            = veth_dev_init,
1601         .ndo_open            = veth_open,
1602         .ndo_stop            = veth_close,
1603         .ndo_start_xmit      = veth_xmit,
1604         .ndo_get_stats64     = veth_get_stats64,
1605         .ndo_set_rx_mode     = veth_set_multicast_list,
1606         .ndo_set_mac_address = eth_mac_addr,
1607 #ifdef CONFIG_NET_POLL_CONTROLLER
1608         .ndo_poll_controller    = veth_poll_controller,
1609 #endif
1610         .ndo_get_iflink         = veth_get_iflink,
1611         .ndo_fix_features       = veth_fix_features,
1612         .ndo_set_features       = veth_set_features,
1613         .ndo_features_check     = passthru_features_check,
1614         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1615         .ndo_bpf                = veth_xdp,
1616         .ndo_xdp_xmit           = veth_ndo_xdp_xmit,
1617         .ndo_get_peer_dev       = veth_peer_dev,
1618 };
1619
1620 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1621                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1622                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1623                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1624                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1625
1626 static void veth_setup(struct net_device *dev)
1627 {
1628         ether_setup(dev);
1629
1630         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1631         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1632         dev->priv_flags |= IFF_NO_QUEUE;
1633         dev->priv_flags |= IFF_PHONY_HEADROOM;
1634
1635         dev->netdev_ops = &veth_netdev_ops;
1636         dev->ethtool_ops = &veth_ethtool_ops;
1637         dev->features |= NETIF_F_LLTX;
1638         dev->features |= VETH_FEATURES;
1639         dev->vlan_features = dev->features &
1640                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1641                                NETIF_F_HW_VLAN_STAG_TX |
1642                                NETIF_F_HW_VLAN_CTAG_RX |
1643                                NETIF_F_HW_VLAN_STAG_RX);
1644         dev->needs_free_netdev = true;
1645         dev->priv_destructor = veth_dev_free;
1646         dev->max_mtu = ETH_MAX_MTU;
1647
1648         dev->hw_features = VETH_FEATURES;
1649         dev->hw_enc_features = VETH_FEATURES;
1650         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1651         netif_set_tso_max_size(dev, GSO_MAX_SIZE);
1652 }
1653
1654 /*
1655  * netlink interface
1656  */
1657
1658 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1659                          struct netlink_ext_ack *extack)
1660 {
1661         if (tb[IFLA_ADDRESS]) {
1662                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1663                         return -EINVAL;
1664                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1665                         return -EADDRNOTAVAIL;
1666         }
1667         if (tb[IFLA_MTU]) {
1668                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1669                         return -EINVAL;
1670         }
1671         return 0;
1672 }
1673
1674 static struct rtnl_link_ops veth_link_ops;
1675
1676 static void veth_disable_gro(struct net_device *dev)
1677 {
1678         dev->features &= ~NETIF_F_GRO;
1679         dev->wanted_features &= ~NETIF_F_GRO;
1680         netdev_update_features(dev);
1681 }
1682
1683 static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
1684 {
1685         int err;
1686
1687         if (!tb[IFLA_NUM_TX_QUEUES] && dev->num_tx_queues > 1) {
1688                 err = netif_set_real_num_tx_queues(dev, 1);
1689                 if (err)
1690                         return err;
1691         }
1692         if (!tb[IFLA_NUM_RX_QUEUES] && dev->num_rx_queues > 1) {
1693                 err = netif_set_real_num_rx_queues(dev, 1);
1694                 if (err)
1695                         return err;
1696         }
1697         return 0;
1698 }
1699
1700 static int veth_newlink(struct net *src_net, struct net_device *dev,
1701                         struct nlattr *tb[], struct nlattr *data[],
1702                         struct netlink_ext_ack *extack)
1703 {
1704         int err;
1705         struct net_device *peer;
1706         struct veth_priv *priv;
1707         char ifname[IFNAMSIZ];
1708         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1709         unsigned char name_assign_type;
1710         struct ifinfomsg *ifmp;
1711         struct net *net;
1712
1713         /*
1714          * create and register peer first
1715          */
1716         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1717                 struct nlattr *nla_peer;
1718
1719                 nla_peer = data[VETH_INFO_PEER];
1720                 ifmp = nla_data(nla_peer);
1721                 err = rtnl_nla_parse_ifla(peer_tb,
1722                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1723                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1724                                           NULL);
1725                 if (err < 0)
1726                         return err;
1727
1728                 err = veth_validate(peer_tb, NULL, extack);
1729                 if (err < 0)
1730                         return err;
1731
1732                 tbp = peer_tb;
1733         } else {
1734                 ifmp = NULL;
1735                 tbp = tb;
1736         }
1737
1738         if (ifmp && tbp[IFLA_IFNAME]) {
1739                 nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1740                 name_assign_type = NET_NAME_USER;
1741         } else {
1742                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1743                 name_assign_type = NET_NAME_ENUM;
1744         }
1745
1746         net = rtnl_link_get_net(src_net, tbp);
1747         if (IS_ERR(net))
1748                 return PTR_ERR(net);
1749
1750         peer = rtnl_create_link(net, ifname, name_assign_type,
1751                                 &veth_link_ops, tbp, extack);
1752         if (IS_ERR(peer)) {
1753                 put_net(net);
1754                 return PTR_ERR(peer);
1755         }
1756
1757         if (!ifmp || !tbp[IFLA_ADDRESS])
1758                 eth_hw_addr_random(peer);
1759
1760         if (ifmp && (dev->ifindex != 0))
1761                 peer->ifindex = ifmp->ifi_index;
1762
1763         netif_inherit_tso_max(peer, dev);
1764
1765         err = register_netdevice(peer);
1766         put_net(net);
1767         net = NULL;
1768         if (err < 0)
1769                 goto err_register_peer;
1770
1771         /* keep GRO disabled by default to be consistent with the established
1772          * veth behavior
1773          */
1774         veth_disable_gro(peer);
1775         netif_carrier_off(peer);
1776
1777         err = rtnl_configure_link(peer, ifmp);
1778         if (err < 0)
1779                 goto err_configure_peer;
1780
1781         /*
1782          * register dev last
1783          *
1784          * note, that since we've registered new device the dev's name
1785          * should be re-allocated
1786          */
1787
1788         if (tb[IFLA_ADDRESS] == NULL)
1789                 eth_hw_addr_random(dev);
1790
1791         if (tb[IFLA_IFNAME])
1792                 nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1793         else
1794                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1795
1796         err = register_netdevice(dev);
1797         if (err < 0)
1798                 goto err_register_dev;
1799
1800         netif_carrier_off(dev);
1801
1802         /*
1803          * tie the deviced together
1804          */
1805
1806         priv = netdev_priv(dev);
1807         rcu_assign_pointer(priv->peer, peer);
1808         err = veth_init_queues(dev, tb);
1809         if (err)
1810                 goto err_queues;
1811
1812         priv = netdev_priv(peer);
1813         rcu_assign_pointer(priv->peer, dev);
1814         err = veth_init_queues(peer, tb);
1815         if (err)
1816                 goto err_queues;
1817
1818         veth_disable_gro(dev);
1819         return 0;
1820
1821 err_queues:
1822         unregister_netdevice(dev);
1823 err_register_dev:
1824         /* nothing to do */
1825 err_configure_peer:
1826         unregister_netdevice(peer);
1827         return err;
1828
1829 err_register_peer:
1830         free_netdev(peer);
1831         return err;
1832 }
1833
1834 static void veth_dellink(struct net_device *dev, struct list_head *head)
1835 {
1836         struct veth_priv *priv;
1837         struct net_device *peer;
1838
1839         priv = netdev_priv(dev);
1840         peer = rtnl_dereference(priv->peer);
1841
1842         /* Note : dellink() is called from default_device_exit_batch(),
1843          * before a rcu_synchronize() point. The devices are guaranteed
1844          * not being freed before one RCU grace period.
1845          */
1846         RCU_INIT_POINTER(priv->peer, NULL);
1847         unregister_netdevice_queue(dev, head);
1848
1849         if (peer) {
1850                 priv = netdev_priv(peer);
1851                 RCU_INIT_POINTER(priv->peer, NULL);
1852                 unregister_netdevice_queue(peer, head);
1853         }
1854 }
1855
1856 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1857         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1858 };
1859
1860 static struct net *veth_get_link_net(const struct net_device *dev)
1861 {
1862         struct veth_priv *priv = netdev_priv(dev);
1863         struct net_device *peer = rtnl_dereference(priv->peer);
1864
1865         return peer ? dev_net(peer) : dev_net(dev);
1866 }
1867
1868 static unsigned int veth_get_num_queues(void)
1869 {
1870         /* enforce the same queue limit as rtnl_create_link */
1871         int queues = num_possible_cpus();
1872
1873         if (queues > 4096)
1874                 queues = 4096;
1875         return queues;
1876 }
1877
1878 static struct rtnl_link_ops veth_link_ops = {
1879         .kind           = DRV_NAME,
1880         .priv_size      = sizeof(struct veth_priv),
1881         .setup          = veth_setup,
1882         .validate       = veth_validate,
1883         .newlink        = veth_newlink,
1884         .dellink        = veth_dellink,
1885         .policy         = veth_policy,
1886         .maxtype        = VETH_INFO_MAX,
1887         .get_link_net   = veth_get_link_net,
1888         .get_num_tx_queues      = veth_get_num_queues,
1889         .get_num_rx_queues      = veth_get_num_queues,
1890 };
1891
1892 /*
1893  * init/fini
1894  */
1895
1896 static __init int veth_init(void)
1897 {
1898         return rtnl_link_register(&veth_link_ops);
1899 }
1900
1901 static __exit void veth_exit(void)
1902 {
1903         rtnl_link_unregister(&veth_link_ops);
1904 }
1905
1906 module_init(veth_init);
1907 module_exit(veth_exit);
1908
1909 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1910 MODULE_LICENSE("GPL v2");
1911 MODULE_ALIAS_RTNL_LINK(DRV_NAME);