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