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         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
 132         strlcpy(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 (done < budget && napi_complete_done(napi, done)) {
 978                 /* Write rx_notify_masked before reading ptr_ring */
 979                 smp_store_mb(rq->rx_notify_masked, false);
 980                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 981                         if (napi_schedule_prep(&rq->xdp_napi)) {
 982                                 WRITE_ONCE(rq->rx_notify_masked, true);
 983                                 __napi_schedule(&rq->xdp_napi);
 984                         }
 985                 }
 986         }
 987
 988         if (stats.xdp_tx > 0)
 989                 veth_xdp_flush(rq, &bq);
 990         if (stats.xdp_redirect > 0)
 991                 xdp_do_flush();
 992         xdp_clear_return_frame_no_direct();
 993
 994         return done;
 995 }
 996
 997 static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
 998 {
 999         struct veth_priv *priv = netdev_priv(dev);
1000         int err, i;
1001
1002         for (i = start; i < end; i++) {
1003                 struct veth_rq *rq = &priv->rq[i];
1004
1005                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
1006                 if (err)
1007                         goto err_xdp_ring;
1008         }
1009
1010         for (i = start; i < end; i++) {
1011                 struct veth_rq *rq = &priv->rq[i];
1012
1013                 napi_enable(&rq->xdp_napi);
1014                 rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1015         }
1016
1017         return 0;
1018
1019 err_xdp_ring:
1020         for (i--; i >= start; i--)
1021                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
1022
1023         return err;
1024 }
1025
1026 static int __veth_napi_enable(struct net_device *dev)
1027 {
1028         return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1029 }
1030
1031 static void veth_napi_del_range(struct net_device *dev, int start, int end)
1032 {
1033         struct veth_priv *priv = netdev_priv(dev);
1034         int i;
1035
1036         for (i = start; i < end; i++) {
1037                 struct veth_rq *rq = &priv->rq[i];
1038
1039                 rcu_assign_pointer(priv->rq[i].napi, NULL);
1040                 napi_disable(&rq->xdp_napi);
1041                 __netif_napi_del(&rq->xdp_napi);
1042         }
1043         synchronize_net();
1044
1045         for (i = start; i < end; i++) {
1046                 struct veth_rq *rq = &priv->rq[i];
1047
1048                 rq->rx_notify_masked = false;
1049                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
1050         }
1051 }
1052
1053 static void veth_napi_del(struct net_device *dev)
1054 {
1055         veth_napi_del_range(dev, 0, dev->real_num_rx_queues);
1056 }
1057
1058 static bool veth_gro_requested(const struct net_device *dev)
1059 {
1060         return !!(dev->wanted_features & NETIF_F_GRO);
1061 }
1062
1063 static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
1064                                  bool napi_already_on)
1065 {
1066         struct veth_priv *priv = netdev_priv(dev);
1067         int err, i;
1068
1069         for (i = start; i < end; i++) {
1070                 struct veth_rq *rq = &priv->rq[i];
1071
1072                 if (!napi_already_on)
1073                         netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
1074                 err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
1075                 if (err < 0)
1076                         goto err_rxq_reg;
1077
1078                 err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
1079                                                  MEM_TYPE_PAGE_SHARED,
1080                                                  NULL);
1081                 if (err < 0)
1082                         goto err_reg_mem;
1083
1084                 /* Save original mem info as it can be overwritten */
1085                 rq->xdp_mem = rq->xdp_rxq.mem;
1086         }
1087         return 0;
1088
1089 err_reg_mem:
1090         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
1091 err_rxq_reg:
1092         for (i--; i >= start; i--) {
1093                 struct veth_rq *rq = &priv->rq[i];
1094
1095                 xdp_rxq_info_unreg(&rq->xdp_rxq);
1096                 if (!napi_already_on)
1097                         netif_napi_del(&rq->xdp_napi);
1098         }
1099
1100         return err;
1101 }
1102
1103 static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
1104                                    bool delete_napi)
1105 {
1106         struct veth_priv *priv = netdev_priv(dev);
1107         int i;
1108
1109         for (i = start; i < end; i++) {
1110                 struct veth_rq *rq = &priv->rq[i];
1111
1112                 rq->xdp_rxq.mem = rq->xdp_mem;
1113                 xdp_rxq_info_unreg(&rq->xdp_rxq);
1114
1115                 if (delete_napi)
1116                         netif_napi_del(&rq->xdp_napi);
1117         }
1118 }
1119
1120 static int veth_enable_xdp(struct net_device *dev)
1121 {
1122         bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP);
1123         struct veth_priv *priv = netdev_priv(dev);
1124         int err, i;
1125
1126         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
1127                 err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
1128                 if (err)
1129                         return err;
1130
1131                 if (!napi_already_on) {
1132                         err = __veth_napi_enable(dev);
1133                         if (err) {
1134                                 veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
1135                                 return err;
1136                         }
1137
1138                         if (!veth_gro_requested(dev)) {
1139                                 /* user-space did not require GRO, but adding XDP
1140                                  * is supposed to get GRO working
1141                                  */
1142                                 dev->features |= NETIF_F_GRO;
1143                                 netdev_features_change(dev);
1144                         }
1145                 }
1146         }
1147
1148         for (i = 0; i < dev->real_num_rx_queues; i++) {
1149                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
1150                 rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1151         }
1152
1153         return 0;
1154 }
1155
1156 static void veth_disable_xdp(struct net_device *dev)
1157 {
1158         struct veth_priv *priv = netdev_priv(dev);
1159         int i;
1160
1161         for (i = 0; i < dev->real_num_rx_queues; i++)
1162                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
1163
1164         if (!netif_running(dev) || !veth_gro_requested(dev)) {
1165                 veth_napi_del(dev);
1166
1167                 /* if user-space did not require GRO, since adding XDP
1168                  * enabled it, clear it now
1169                  */
1170                 if (!veth_gro_requested(dev) && netif_running(dev)) {
1171                         dev->features &= ~NETIF_F_GRO;
1172                         netdev_features_change(dev);
1173                 }
1174         }
1175
1176         veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
1177 }
1178
1179 static int veth_napi_enable_range(struct net_device *dev, int start, int end)
1180 {
1181         struct veth_priv *priv = netdev_priv(dev);
1182         int err, i;
1183
1184         for (i = start; i < end; i++) {
1185                 struct veth_rq *rq = &priv->rq[i];
1186
1187                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
1188         }
1189
1190         err = __veth_napi_enable_range(dev, start, end);
1191         if (err) {
1192                 for (i = start; i < end; i++) {
1193                         struct veth_rq *rq = &priv->rq[i];
1194
1195                         netif_napi_del(&rq->xdp_napi);
1196                 }
1197                 return err;
1198         }
1199         return err;
1200 }
1201
1202 static int veth_napi_enable(struct net_device *dev)
1203 {
1204         return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1205 }
1206
1207 static void veth_disable_range_safe(struct net_device *dev, int start, int end)
1208 {
1209         struct veth_priv *priv = netdev_priv(dev);
1210
1211         if (start >= end)
1212                 return;
1213
1214         if (priv->_xdp_prog) {
1215                 veth_napi_del_range(dev, start, end);
1216                 veth_disable_xdp_range(dev, start, end, false);
1217         } else if (veth_gro_requested(dev)) {
1218                 veth_napi_del_range(dev, start, end);
1219         }
1220 }
1221
1222 static int veth_enable_range_safe(struct net_device *dev, int start, int end)
1223 {
1224         struct veth_priv *priv = netdev_priv(dev);
1225         int err;
1226
1227         if (start >= end)
1228                 return 0;
1229
1230         if (priv->_xdp_prog) {
1231                 /* these channels are freshly initialized, napi is not on there even
1232                  * when GRO is requeste
1233                  */
1234                 err = veth_enable_xdp_range(dev, start, end, false);
1235                 if (err)
1236                         return err;
1237
1238                 err = __veth_napi_enable_range(dev, start, end);
1239                 if (err) {
1240                         /* on error always delete the newly added napis */
1241                         veth_disable_xdp_range(dev, start, end, true);
1242                         return err;
1243                 }
1244         } else if (veth_gro_requested(dev)) {
1245                 return veth_napi_enable_range(dev, start, end);
1246         }
1247         return 0;
1248 }
1249
1250 static int veth_set_channels(struct net_device *dev,
1251                              struct ethtool_channels *ch)
1252 {
1253         struct veth_priv *priv = netdev_priv(dev);
1254         unsigned int old_rx_count, new_rx_count;
1255         struct veth_priv *peer_priv;
1256         struct net_device *peer;
1257         int err;
1258
1259         /* sanity check. Upper bounds are already enforced by the caller */
1260         if (!ch->rx_count || !ch->tx_count)
1261                 return -EINVAL;
1262
1263         /* avoid braking XDP, if that is enabled */
1264         peer = rtnl_dereference(priv->peer);
1265         peer_priv = peer ? netdev_priv(peer) : NULL;
1266         if (priv->_xdp_prog && peer && ch->rx_count < peer->real_num_tx_queues)
1267                 return -EINVAL;
1268
1269         if (peer && peer_priv && peer_priv->_xdp_prog && ch->tx_count > peer->real_num_rx_queues)
1270                 return -EINVAL;
1271
1272         old_rx_count = dev->real_num_rx_queues;
1273         new_rx_count = ch->rx_count;
1274         if (netif_running(dev)) {
1275                 /* turn device off */
1276                 netif_carrier_off(dev);
1277                 if (peer)
1278                         netif_carrier_off(peer);
1279
1280                 /* try to allocate new resurces, as needed*/
1281                 err = veth_enable_range_safe(dev, old_rx_count, new_rx_count);
1282                 if (err)
1283                         goto out;
1284         }
1285
1286         err = netif_set_real_num_rx_queues(dev, ch->rx_count);
1287         if (err)
1288                 goto revert;
1289
1290         err = netif_set_real_num_tx_queues(dev, ch->tx_count);
1291         if (err) {
1292                 int err2 = netif_set_real_num_rx_queues(dev, old_rx_count);
1293
1294                 /* this error condition could happen only if rx and tx change
1295                  * in opposite directions (e.g. tx nr raises, rx nr decreases)
1296                  * and we can't do anything to fully restore the original
1297                  * status
1298                  */
1299                 if (err2)
1300                         pr_warn("Can't restore rx queues config %d -> %d %d",
1301                                 new_rx_count, old_rx_count, err2);
1302                 else
1303                         goto revert;
1304         }
1305
1306 out:
1307         if (netif_running(dev)) {
1308                 /* note that we need to swap the arguments WRT the enable part
1309                  * to identify the range we have to disable
1310                  */
1311                 veth_disable_range_safe(dev, new_rx_count, old_rx_count);
1312                 netif_carrier_on(dev);
1313                 if (peer)
1314                         netif_carrier_on(peer);
1315         }
1316         return err;
1317
1318 revert:
1319         new_rx_count = old_rx_count;
1320         old_rx_count = ch->rx_count;
1321         goto out;
1322 }
1323
1324 static int veth_open(struct net_device *dev)
1325 {
1326         struct veth_priv *priv = netdev_priv(dev);
1327         struct net_device *peer = rtnl_dereference(priv->peer);
1328         int err;
1329
1330         if (!peer)
1331                 return -ENOTCONN;
1332
1333         if (priv->_xdp_prog) {
1334                 err = veth_enable_xdp(dev);
1335                 if (err)
1336                         return err;
1337         } else if (veth_gro_requested(dev)) {
1338                 err = veth_napi_enable(dev);
1339                 if (err)
1340                         return err;
1341         }
1342
1343         if (peer->flags & IFF_UP) {
1344                 netif_carrier_on(dev);
1345                 netif_carrier_on(peer);
1346         }
1347
1348         return 0;
1349 }
1350
1351 static int veth_close(struct net_device *dev)
1352 {
1353         struct veth_priv *priv = netdev_priv(dev);
1354         struct net_device *peer = rtnl_dereference(priv->peer);
1355
1356         netif_carrier_off(dev);
1357         if (peer)
1358                 netif_carrier_off(peer);
1359
1360         if (priv->_xdp_prog)
1361                 veth_disable_xdp(dev);
1362         else if (veth_gro_requested(dev))
1363                 veth_napi_del(dev);
1364
1365         return 0;
1366 }
1367
1368 static int is_valid_veth_mtu(int mtu)
1369 {
1370         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
1371 }
1372
1373 static int veth_alloc_queues(struct net_device *dev)
1374 {
1375         struct veth_priv *priv = netdev_priv(dev);
1376         int i;
1377
1378         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
1379         if (!priv->rq)
1380                 return -ENOMEM;
1381
1382         for (i = 0; i < dev->num_rx_queues; i++) {
1383                 priv->rq[i].dev = dev;
1384                 u64_stats_init(&priv->rq[i].stats.syncp);
1385         }
1386
1387         return 0;
1388 }
1389
1390 static void veth_free_queues(struct net_device *dev)
1391 {
1392         struct veth_priv *priv = netdev_priv(dev);
1393
1394         kfree(priv->rq);
1395 }
1396
1397 static int veth_dev_init(struct net_device *dev)
1398 {
1399         int err;
1400
1401         dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
1402         if (!dev->lstats)
1403                 return -ENOMEM;
1404
1405         err = veth_alloc_queues(dev);
1406         if (err) {
1407                 free_percpu(dev->lstats);
1408                 return err;
1409         }
1410
1411         return 0;
1412 }
1413
1414 static void veth_dev_free(struct net_device *dev)
1415 {
1416         veth_free_queues(dev);
1417         free_percpu(dev->lstats);
1418 }
1419
1420 #ifdef CONFIG_NET_POLL_CONTROLLER
1421 static void veth_poll_controller(struct net_device *dev)
1422 {
1423         /* veth only receives frames when its peer sends one
1424          * Since it has nothing to do with disabling irqs, we are guaranteed
1425          * never to have pending data when we poll for it so
1426          * there is nothing to do here.
1427          *
1428          * We need this though so netpoll recognizes us as an interface that
1429          * supports polling, which enables bridge devices in virt setups to
1430          * still use netconsole
1431          */
1432 }
1433 #endif  /* CONFIG_NET_POLL_CONTROLLER */
1434
1435 static int veth_get_iflink(const struct net_device *dev)
1436 {
1437         struct veth_priv *priv = netdev_priv(dev);
1438         struct net_device *peer;
1439         int iflink;
1440
1441         rcu_read_lock();
1442         peer = rcu_dereference(priv->peer);
1443         iflink = peer ? peer->ifindex : 0;
1444         rcu_read_unlock();
1445
1446         return iflink;
1447 }
1448
1449 static netdev_features_t veth_fix_features(struct net_device *dev,
1450                                            netdev_features_t features)
1451 {
1452         struct veth_priv *priv = netdev_priv(dev);
1453         struct net_device *peer;
1454
1455         peer = rtnl_dereference(priv->peer);
1456         if (peer) {
1457                 struct veth_priv *peer_priv = netdev_priv(peer);
1458
1459                 if (peer_priv->_xdp_prog)
1460                         features &= ~NETIF_F_GSO_SOFTWARE;
1461         }
1462         if (priv->_xdp_prog)
1463                 features |= NETIF_F_GRO;
1464
1465         return features;
1466 }
1467
1468 static int veth_set_features(struct net_device *dev,
1469                              netdev_features_t features)
1470 {
1471         netdev_features_t changed = features ^ dev->features;
1472         struct veth_priv *priv = netdev_priv(dev);
1473         int err;
1474
1475         if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
1476                 return 0;
1477
1478         if (features & NETIF_F_GRO) {
1479                 err = veth_napi_enable(dev);
1480                 if (err)
1481                         return err;
1482         } else {
1483                 veth_napi_del(dev);
1484         }
1485         return 0;
1486 }
1487
1488 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1489 {
1490         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1491         struct net_device *peer;
1492
1493         if (new_hr < 0)
1494                 new_hr = 0;
1495
1496         rcu_read_lock();
1497         peer = rcu_dereference(priv->peer);
1498         if (unlikely(!peer))
1499                 goto out;
1500
1501         peer_priv = netdev_priv(peer);
1502         priv->requested_headroom = new_hr;
1503         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1504         dev->needed_headroom = new_hr;
1505         peer->needed_headroom = new_hr;
1506
1507 out:
1508         rcu_read_unlock();
1509 }
1510
1511 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1512                         struct netlink_ext_ack *extack)
1513 {
1514         struct veth_priv *priv = netdev_priv(dev);
1515         struct bpf_prog *old_prog;
1516         struct net_device *peer;
1517         unsigned int max_mtu;
1518         int err;
1519
1520         old_prog = priv->_xdp_prog;
1521         priv->_xdp_prog = prog;
1522         peer = rtnl_dereference(priv->peer);
1523
1524         if (prog) {
1525                 if (!peer) {
1526                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1527                         err = -ENOTCONN;
1528                         goto err;
1529                 }
1530
1531                 max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
1532                           peer->hard_header_len;
1533                 /* Allow increasing the max_mtu if the program supports
1534                  * XDP fragments.
1535                  */
1536                 if (prog->aux->xdp_has_frags)
1537                         max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;
1538
1539                 if (peer->mtu > max_mtu) {
1540                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1541                         err = -ERANGE;
1542                         goto err;
1543                 }
1544
1545                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1546                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1547                         err = -ENOSPC;
1548                         goto err;
1549                 }
1550
1551                 if (dev->flags & IFF_UP) {
1552                         err = veth_enable_xdp(dev);
1553                         if (err) {
1554                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1555                                 goto err;
1556                         }
1557                 }
1558
1559                 if (!old_prog) {
1560                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1561                         peer->max_mtu = max_mtu;
1562                 }
1563         }
1564
1565         if (old_prog) {
1566                 if (!prog) {
1567                         if (dev->flags & IFF_UP)
1568                                 veth_disable_xdp(dev);
1569
1570                         if (peer) {
1571                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1572                                 peer->max_mtu = ETH_MAX_MTU;
1573                         }
1574                 }
1575                 bpf_prog_put(old_prog);
1576         }
1577
1578         if ((!!old_prog ^ !!prog) && peer)
1579                 netdev_update_features(peer);
1580
1581         return 0;
1582 err:
1583         priv->_xdp_prog = old_prog;
1584
1585         return err;
1586 }
1587
1588 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1589 {
1590         switch (xdp->command) {
1591         case XDP_SETUP_PROG:
1592                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
1593         default:
1594                 return -EINVAL;
1595         }
1596 }
1597
1598 static const struct net_device_ops veth_netdev_ops = {
1599         .ndo_init            = veth_dev_init,
1600         .ndo_open            = veth_open,
1601         .ndo_stop            = veth_close,
1602         .ndo_start_xmit      = veth_xmit,
1603         .ndo_get_stats64     = veth_get_stats64,
1604         .ndo_set_rx_mode     = veth_set_multicast_list,
1605         .ndo_set_mac_address = eth_mac_addr,
1606 #ifdef CONFIG_NET_POLL_CONTROLLER
1607         .ndo_poll_controller    = veth_poll_controller,
1608 #endif
1609         .ndo_get_iflink         = veth_get_iflink,
1610         .ndo_fix_features       = veth_fix_features,
1611         .ndo_set_features       = veth_set_features,
1612         .ndo_features_check     = passthru_features_check,
1613         .ndo_set_rx_headroom    = veth_set_rx_headroom,
1614         .ndo_bpf                = veth_xdp,
1615         .ndo_xdp_xmit           = veth_ndo_xdp_xmit,
1616         .ndo_get_peer_dev       = veth_peer_dev,
1617 };
1618
1619 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1620                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1621                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1622                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1623                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1624
1625 static void veth_setup(struct net_device *dev)
1626 {
1627         ether_setup(dev);
1628
1629         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1630         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1631         dev->priv_flags |= IFF_NO_QUEUE;
1632         dev->priv_flags |= IFF_PHONY_HEADROOM;
1633
1634         dev->netdev_ops = &veth_netdev_ops;
1635         dev->ethtool_ops = &veth_ethtool_ops;
1636         dev->features |= NETIF_F_LLTX;
1637         dev->features |= VETH_FEATURES;
1638         dev->vlan_features = dev->features &
1639                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1640                                NETIF_F_HW_VLAN_STAG_TX |
1641                                NETIF_F_HW_VLAN_CTAG_RX |
1642                                NETIF_F_HW_VLAN_STAG_RX);
1643         dev->needs_free_netdev = true;
1644         dev->priv_destructor = veth_dev_free;
1645         dev->max_mtu = ETH_MAX_MTU;
1646
1647         dev->hw_features = VETH_FEATURES;
1648         dev->hw_enc_features = VETH_FEATURES;
1649         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1650 }
1651
1652 /*
1653  * netlink interface
1654  */
1655
1656 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1657                          struct netlink_ext_ack *extack)
1658 {
1659         if (tb[IFLA_ADDRESS]) {
1660                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1661                         return -EINVAL;
1662                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1663                         return -EADDRNOTAVAIL;
1664         }
1665         if (tb[IFLA_MTU]) {
1666                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1667                         return -EINVAL;
1668         }
1669         return 0;
1670 }
1671
1672 static struct rtnl_link_ops veth_link_ops;
1673
1674 static void veth_disable_gro(struct net_device *dev)
1675 {
1676         dev->features &= ~NETIF_F_GRO;
1677         dev->wanted_features &= ~NETIF_F_GRO;
1678         netdev_update_features(dev);
1679 }
1680
1681 static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
1682 {
1683         int err;
1684
1685         if (!tb[IFLA_NUM_TX_QUEUES] && dev->num_tx_queues > 1) {
1686                 err = netif_set_real_num_tx_queues(dev, 1);
1687                 if (err)
1688                         return err;
1689         }
1690         if (!tb[IFLA_NUM_RX_QUEUES] && dev->num_rx_queues > 1) {
1691                 err = netif_set_real_num_rx_queues(dev, 1);
1692                 if (err)
1693                         return err;
1694         }
1695         return 0;
1696 }
1697
1698 static int veth_newlink(struct net *src_net, struct net_device *dev,
1699                         struct nlattr *tb[], struct nlattr *data[],
1700                         struct netlink_ext_ack *extack)
1701 {
1702         int err;
1703         struct net_device *peer;
1704         struct veth_priv *priv;
1705         char ifname[IFNAMSIZ];
1706         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1707         unsigned char name_assign_type;
1708         struct ifinfomsg *ifmp;
1709         struct net *net;
1710
1711         /*
1712          * create and register peer first
1713          */
1714         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1715                 struct nlattr *nla_peer;
1716
1717                 nla_peer = data[VETH_INFO_PEER];
1718                 ifmp = nla_data(nla_peer);
1719                 err = rtnl_nla_parse_ifla(peer_tb,
1720                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1721                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1722                                           NULL);
1723                 if (err < 0)
1724                         return err;
1725
1726                 err = veth_validate(peer_tb, NULL, extack);
1727                 if (err < 0)
1728                         return err;
1729
1730                 tbp = peer_tb;
1731         } else {
1732                 ifmp = NULL;
1733                 tbp = tb;
1734         }
1735
1736         if (ifmp && tbp[IFLA_IFNAME]) {
1737                 nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1738                 name_assign_type = NET_NAME_USER;
1739         } else {
1740                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1741                 name_assign_type = NET_NAME_ENUM;
1742         }
1743
1744         net = rtnl_link_get_net(src_net, tbp);
1745         if (IS_ERR(net))
1746                 return PTR_ERR(net);
1747
1748         peer = rtnl_create_link(net, ifname, name_assign_type,
1749                                 &veth_link_ops, tbp, extack);
1750         if (IS_ERR(peer)) {
1751                 put_net(net);
1752                 return PTR_ERR(peer);
1753         }
1754
1755         if (!ifmp || !tbp[IFLA_ADDRESS])
1756                 eth_hw_addr_random(peer);
1757
1758         if (ifmp && (dev->ifindex != 0))
1759                 peer->ifindex = ifmp->ifi_index;
1760
1761         netif_set_gso_max_size(peer, dev->gso_max_size);
1762         netif_set_gso_max_segs(peer, dev->gso_max_segs);
1763
1764         err = register_netdevice(peer);
1765         put_net(net);
1766         net = NULL;
1767         if (err < 0)
1768                 goto err_register_peer;
1769
1770         /* keep GRO disabled by default to be consistent with the established
1771          * veth behavior
1772          */
1773         veth_disable_gro(peer);
1774         netif_carrier_off(peer);
1775
1776         err = rtnl_configure_link(peer, ifmp);
1777         if (err < 0)
1778                 goto err_configure_peer;
1779
1780         /*
1781          * register dev last
1782          *
1783          * note, that since we've registered new device the dev's name
1784          * should be re-allocated
1785          */
1786
1787         if (tb[IFLA_ADDRESS] == NULL)
1788                 eth_hw_addr_random(dev);
1789
1790         if (tb[IFLA_IFNAME])
1791                 nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1792         else
1793                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1794
1795         err = register_netdevice(dev);
1796         if (err < 0)
1797                 goto err_register_dev;
1798
1799         netif_carrier_off(dev);
1800
1801         /*
1802          * tie the deviced together
1803          */
1804
1805         priv = netdev_priv(dev);
1806         rcu_assign_pointer(priv->peer, peer);
1807         err = veth_init_queues(dev, tb);
1808         if (err)
1809                 goto err_queues;
1810
1811         priv = netdev_priv(peer);
1812         rcu_assign_pointer(priv->peer, dev);
1813         err = veth_init_queues(peer, tb);
1814         if (err)
1815                 goto err_queues;
1816
1817         veth_disable_gro(dev);
1818         return 0;
1819
1820 err_queues:
1821         unregister_netdevice(dev);
1822 err_register_dev:
1823         /* nothing to do */
1824 err_configure_peer:
1825         unregister_netdevice(peer);
1826         return err;
1827
1828 err_register_peer:
1829         free_netdev(peer);
1830         return err;
1831 }
1832
1833 static void veth_dellink(struct net_device *dev, struct list_head *head)
1834 {
1835         struct veth_priv *priv;
1836         struct net_device *peer;
1837
1838         priv = netdev_priv(dev);
1839         peer = rtnl_dereference(priv->peer);
1840
1841         /* Note : dellink() is called from default_device_exit_batch(),
1842          * before a rcu_synchronize() point. The devices are guaranteed
1843          * not being freed before one RCU grace period.
1844          */
1845         RCU_INIT_POINTER(priv->peer, NULL);
1846         unregister_netdevice_queue(dev, head);
1847
1848         if (peer) {
1849                 priv = netdev_priv(peer);
1850                 RCU_INIT_POINTER(priv->peer, NULL);
1851                 unregister_netdevice_queue(peer, head);
1852         }
1853 }
1854
1855 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1856         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1857 };
1858
1859 static struct net *veth_get_link_net(const struct net_device *dev)
1860 {
1861         struct veth_priv *priv = netdev_priv(dev);
1862         struct net_device *peer = rtnl_dereference(priv->peer);
1863
1864         return peer ? dev_net(peer) : dev_net(dev);
1865 }
1866
1867 static unsigned int veth_get_num_queues(void)
1868 {
1869         /* enforce the same queue limit as rtnl_create_link */
1870         int queues = num_possible_cpus();
1871
1872         if (queues > 4096)
1873                 queues = 4096;
1874         return queues;
1875 }
1876
1877 static struct rtnl_link_ops veth_link_ops = {
1878         .kind           = DRV_NAME,
1879         .priv_size      = sizeof(struct veth_priv),
1880         .setup          = veth_setup,
1881         .validate       = veth_validate,
1882         .newlink        = veth_newlink,
1883         .dellink        = veth_dellink,
1884         .policy         = veth_policy,
1885         .maxtype        = VETH_INFO_MAX,
1886         .get_link_net   = veth_get_link_net,
1887         .get_num_tx_queues      = veth_get_num_queues,
1888         .get_num_rx_queues      = veth_get_num_queues,
1889 };
1890
1891 /*
1892  * init/fini
1893  */
1894
1895 static __init int veth_init(void)
1896 {
1897         return rtnl_link_register(&veth_link_ops);
1898 }
1899
1900 static __exit void veth_exit(void)
1901 {
1902         rtnl_link_unregister(&veth_link_ops);
1903 }
1904
1905 module_init(veth_init);
1906 module_exit(veth_exit);
1907
1908 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1909 MODULE_LICENSE("GPL v2");
1910 MODULE_ALIAS_RTNL_LINK(DRV_NAME);