drivers/net/veth.c

   1 /*
   2  *  drivers/net/veth.c
   3  *
   4  *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
   5  *
   6  * Author: Pavel Emelianov <xemul@openvz.org>
   7  * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
   8  *
   9  */
  10
  11 #include <linux/netdevice.h>
  12 #include <linux/slab.h>
  13 #include <linux/ethtool.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/u64_stats_sync.h>
  16
  17 #include <net/rtnetlink.h>
  18 #include <net/dst.h>
  19 #include <net/xfrm.h>
  20 #include <net/xdp.h>
  21 #include <linux/veth.h>
  22 #include <linux/module.h>
  23 #include <linux/bpf.h>
  24 #include <linux/filter.h>
  25 #include <linux/ptr_ring.h>
  26 #include <linux/bpf_trace.h>
  27
  28 #define DRV_NAME        "veth"
  29 #define DRV_VERSION     "1.0"
  30
  31 #define VETH_XDP_FLAG           BIT(0)
  32 #define VETH_RING_SIZE          256
  33 #define VETH_XDP_HEADROOM       (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
  34
  35 /* Separating two types of XDP xmit */
  36 #define VETH_XDP_TX             BIT(0)
  37 #define VETH_XDP_REDIR          BIT(1)
  38
  39 struct pcpu_vstats {
  40         u64                     packets;
  41         u64                     bytes;
  42         struct u64_stats_sync   syncp;
  43 };
  44
  45 struct veth_rq {
  46         struct napi_struct      xdp_napi;
  47         struct net_device       *dev;
  48         struct bpf_prog __rcu   *xdp_prog;
  49         struct xdp_mem_info     xdp_mem;
  50         bool                    rx_notify_masked;
  51         struct ptr_ring         xdp_ring;
  52         struct xdp_rxq_info     xdp_rxq;
  53 };
  54
  55 struct veth_priv {
  56         struct net_device __rcu *peer;
  57         atomic64_t              dropped;
  58         struct bpf_prog         *_xdp_prog;
  59         struct veth_rq          *rq;
  60         unsigned int            requested_headroom;
  61 };
  62
  63 /*
  64  * ethtool interface
  65  */
  66
  67 static struct {
  68         const char string[ETH_GSTRING_LEN];
  69 } ethtool_stats_keys[] = {
  70         { "peer_ifindex" },
  71 };
  72
  73 static int veth_get_link_ksettings(struct net_device *dev,
  74                                    struct ethtool_link_ksettings *cmd)
  75 {
  76         cmd->base.speed         = SPEED_10000;
  77         cmd->base.duplex        = DUPLEX_FULL;
  78         cmd->base.port          = PORT_TP;
  79         cmd->base.autoneg       = AUTONEG_DISABLE;
  80         return 0;
  81 }
  82
  83 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
  84 {
  85         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
  86         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
  87 }
  88
  89 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
  90 {
  91         switch(stringset) {
  92         case ETH_SS_STATS:
  93                 memcpy(buf, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
  94                 break;
  95         }
  96 }
  97
  98 static int veth_get_sset_count(struct net_device *dev, int sset)
  99 {
 100         switch (sset) {
 101         case ETH_SS_STATS:
 102                 return ARRAY_SIZE(ethtool_stats_keys);
 103         default:
 104                 return -EOPNOTSUPP;
 105         }
 106 }
 107
 108 static void veth_get_ethtool_stats(struct net_device *dev,
 109                 struct ethtool_stats *stats, u64 *data)
 110 {
 111         struct veth_priv *priv = netdev_priv(dev);
 112         struct net_device *peer = rtnl_dereference(priv->peer);
 113
 114         data[0] = peer ? peer->ifindex : 0;
 115 }
 116
 117 static const struct ethtool_ops veth_ethtool_ops = {
 118         .get_drvinfo            = veth_get_drvinfo,
 119         .get_link               = ethtool_op_get_link,
 120         .get_strings            = veth_get_strings,
 121         .get_sset_count         = veth_get_sset_count,
 122         .get_ethtool_stats      = veth_get_ethtool_stats,
 123         .get_link_ksettings     = veth_get_link_ksettings,
 124 };
 125
 126 /* general routines */
 127
 128 static bool veth_is_xdp_frame(void *ptr)
 129 {
 130         return (unsigned long)ptr & VETH_XDP_FLAG;
 131 }
 132
 133 static void *veth_ptr_to_xdp(void *ptr)
 134 {
 135         return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
 136 }
 137
 138 static void *veth_xdp_to_ptr(void *ptr)
 139 {
 140         return (void *)((unsigned long)ptr | VETH_XDP_FLAG);
 141 }
 142
 143 static void veth_ptr_free(void *ptr)
 144 {
 145         if (veth_is_xdp_frame(ptr))
 146                 xdp_return_frame(veth_ptr_to_xdp(ptr));
 147         else
 148                 kfree_skb(ptr);
 149 }
 150
 151 static void __veth_xdp_flush(struct veth_rq *rq)
 152 {
 153         /* Write ptr_ring before reading rx_notify_masked */
 154         smp_mb();
 155         if (!rq->rx_notify_masked) {
 156                 rq->rx_notify_masked = true;
 157                 napi_schedule(&rq->xdp_napi);
 158         }
 159 }
 160
 161 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
 162 {
 163         if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
 164                 dev_kfree_skb_any(skb);
 165                 return NET_RX_DROP;
 166         }
 167
 168         return NET_RX_SUCCESS;
 169 }
 170
 171 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
 172                             struct veth_rq *rq, bool xdp)
 173 {
 174         return __dev_forward_skb(dev, skb) ?: xdp ?
 175                 veth_xdp_rx(rq, skb) :
 176                 netif_rx(skb);
 177 }
 178
 179 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 180 {
 181         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 182         struct veth_rq *rq = NULL;
 183         struct net_device *rcv;
 184         int length = skb->len;
 185         bool rcv_xdp = false;
 186         int rxq;
 187
 188         rcu_read_lock();
 189         rcv = rcu_dereference(priv->peer);
 190         if (unlikely(!rcv)) {
 191                 kfree_skb(skb);
 192                 goto drop;
 193         }
 194
 195         rcv_priv = netdev_priv(rcv);
 196         rxq = skb_get_queue_mapping(skb);
 197         if (rxq < rcv->real_num_rx_queues) {
 198                 rq = &rcv_priv->rq[rxq];
 199                 rcv_xdp = rcu_access_pointer(rq->xdp_prog);
 200                 if (rcv_xdp)
 201                         skb_record_rx_queue(skb, rxq);
 202         }
 203
 204         if (likely(veth_forward_skb(rcv, skb, rq, rcv_xdp) == NET_RX_SUCCESS)) {
 205                 struct pcpu_vstats *stats = this_cpu_ptr(dev->vstats);
 206
 207                 u64_stats_update_begin(&stats->syncp);
 208                 stats->bytes += length;
 209                 stats->packets++;
 210                 u64_stats_update_end(&stats->syncp);
 211         } else {
 212 drop:
 213                 atomic64_inc(&priv->dropped);
 214         }
 215
 216         if (rcv_xdp)
 217                 __veth_xdp_flush(rq);
 218
 219         rcu_read_unlock();
 220
 221         return NETDEV_TX_OK;
 222 }
 223
 224 static u64 veth_stats_one(struct pcpu_vstats *result, struct net_device *dev)
 225 {
 226         struct veth_priv *priv = netdev_priv(dev);
 227         int cpu;
 228
 229         result->packets = 0;
 230         result->bytes = 0;
 231         for_each_possible_cpu(cpu) {
 232                 struct pcpu_vstats *stats = per_cpu_ptr(dev->vstats, cpu);
 233                 u64 packets, bytes;
 234                 unsigned int start;
 235
 236                 do {
 237                         start = u64_stats_fetch_begin_irq(&stats->syncp);
 238                         packets = stats->packets;
 239                         bytes = stats->bytes;
 240                 } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
 241                 result->packets += packets;
 242                 result->bytes += bytes;
 243         }
 244         return atomic64_read(&priv->dropped);
 245 }
 246
 247 static void veth_get_stats64(struct net_device *dev,
 248                              struct rtnl_link_stats64 *tot)
 249 {
 250         struct veth_priv *priv = netdev_priv(dev);
 251         struct net_device *peer;
 252         struct pcpu_vstats one;
 253
 254         tot->tx_dropped = veth_stats_one(&one, dev);
 255         tot->tx_bytes = one.bytes;
 256         tot->tx_packets = one.packets;
 257
 258         rcu_read_lock();
 259         peer = rcu_dereference(priv->peer);
 260         if (peer) {
 261                 tot->rx_dropped = veth_stats_one(&one, peer);
 262                 tot->rx_bytes = one.bytes;
 263                 tot->rx_packets = one.packets;
 264         }
 265         rcu_read_unlock();
 266 }
 267
 268 /* fake multicast ability */
 269 static void veth_set_multicast_list(struct net_device *dev)
 270 {
 271 }
 272
 273 static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
 274                                       int buflen)
 275 {
 276         struct sk_buff *skb;
 277
 278         if (!buflen) {
 279                 buflen = SKB_DATA_ALIGN(headroom + len) +
 280                          SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 281         }
 282         skb = build_skb(head, buflen);
 283         if (!skb)
 284                 return NULL;
 285
 286         skb_reserve(skb, headroom);
 287         skb_put(skb, len);
 288
 289         return skb;
 290 }
 291
 292 static int veth_select_rxq(struct net_device *dev)
 293 {
 294         return smp_processor_id() % dev->real_num_rx_queues;
 295 }
 296
 297 static int veth_xdp_xmit(struct net_device *dev, int n,
 298                          struct xdp_frame **frames, u32 flags)
 299 {
 300         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 301         struct net_device *rcv;
 302         unsigned int max_len;
 303         struct veth_rq *rq;
 304         int i, drops = 0;
 305
 306         if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
 307                 return -EINVAL;
 308
 309         rcv = rcu_dereference(priv->peer);
 310         if (unlikely(!rcv))
 311                 return -ENXIO;
 312
 313         rcv_priv = netdev_priv(rcv);
 314         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 315         /* Non-NULL xdp_prog ensures that xdp_ring is initialized on receive
 316          * side. This means an XDP program is loaded on the peer and the peer
 317          * device is up.
 318          */
 319         if (!rcu_access_pointer(rq->xdp_prog))
 320                 return -ENXIO;
 321
 322         max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
 323
 324         spin_lock(&rq->xdp_ring.producer_lock);
 325         for (i = 0; i < n; i++) {
 326                 struct xdp_frame *frame = frames[i];
 327                 void *ptr = veth_xdp_to_ptr(frame);
 328
 329                 if (unlikely(frame->len > max_len ||
 330                              __ptr_ring_produce(&rq->xdp_ring, ptr))) {
 331                         xdp_return_frame_rx_napi(frame);
 332                         drops++;
 333                 }
 334         }
 335         spin_unlock(&rq->xdp_ring.producer_lock);
 336
 337         if (flags & XDP_XMIT_FLUSH)
 338                 __veth_xdp_flush(rq);
 339
 340         return n - drops;
 341 }
 342
 343 static void veth_xdp_flush(struct net_device *dev)
 344 {
 345         struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
 346         struct net_device *rcv;
 347         struct veth_rq *rq;
 348
 349         rcu_read_lock();
 350         rcv = rcu_dereference(priv->peer);
 351         if (unlikely(!rcv))
 352                 goto out;
 353
 354         rcv_priv = netdev_priv(rcv);
 355         rq = &rcv_priv->rq[veth_select_rxq(rcv)];
 356         /* xdp_ring is initialized on receive side? */
 357         if (unlikely(!rcu_access_pointer(rq->xdp_prog)))
 358                 goto out;
 359
 360         __veth_xdp_flush(rq);
 361 out:
 362         rcu_read_unlock();
 363 }
 364
 365 static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
 366 {
 367         struct xdp_frame *frame = convert_to_xdp_frame(xdp);
 368
 369         if (unlikely(!frame))
 370                 return -EOVERFLOW;
 371
 372         return veth_xdp_xmit(dev, 1, &frame, 0);
 373 }
 374
 375 static struct sk_buff *veth_xdp_rcv_one(struct veth_rq *rq,
 376                                         struct xdp_frame *frame,
 377                                         unsigned int *xdp_xmit)
 378 {
 379         void *hard_start = frame->data - frame->headroom;
 380         void *head = hard_start - sizeof(struct xdp_frame);
 381         int len = frame->len, delta = 0;
 382         struct xdp_frame orig_frame;
 383         struct bpf_prog *xdp_prog;
 384         unsigned int headroom;
 385         struct sk_buff *skb;
 386
 387         rcu_read_lock();
 388         xdp_prog = rcu_dereference(rq->xdp_prog);
 389         if (likely(xdp_prog)) {
 390                 struct xdp_buff xdp;
 391                 u32 act;
 392
 393                 xdp.data_hard_start = hard_start;
 394                 xdp.data = frame->data;
 395                 xdp.data_end = frame->data + frame->len;
 396                 xdp.data_meta = frame->data - frame->metasize;
 397                 xdp.rxq = &rq->xdp_rxq;
 398
 399                 act = bpf_prog_run_xdp(xdp_prog, &xdp);
 400
 401                 switch (act) {
 402                 case XDP_PASS:
 403                         delta = frame->data - xdp.data;
 404                         len = xdp.data_end - xdp.data;
 405                         break;
 406                 case XDP_TX:
 407                         orig_frame = *frame;
 408                         xdp.data_hard_start = head;
 409                         xdp.rxq->mem = frame->mem;
 410                         if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 411                                 trace_xdp_exception(rq->dev, xdp_prog, act);
 412                                 frame = &orig_frame;
 413                                 goto err_xdp;
 414                         }
 415                         *xdp_xmit |= VETH_XDP_TX;
 416                         rcu_read_unlock();
 417                         goto xdp_xmit;
 418                 case XDP_REDIRECT:
 419                         orig_frame = *frame;
 420                         xdp.data_hard_start = head;
 421                         xdp.rxq->mem = frame->mem;
 422                         if (xdp_do_redirect(rq->dev, &xdp, xdp_prog)) {
 423                                 frame = &orig_frame;
 424                                 goto err_xdp;
 425                         }
 426                         *xdp_xmit |= VETH_XDP_REDIR;
 427                         rcu_read_unlock();
 428                         goto xdp_xmit;
 429                 default:
 430                         bpf_warn_invalid_xdp_action(act);
 431                 case XDP_ABORTED:
 432                         trace_xdp_exception(rq->dev, xdp_prog, act);
 433                 case XDP_DROP:
 434                         goto err_xdp;
 435                 }
 436         }
 437         rcu_read_unlock();
 438
 439         headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
 440         skb = veth_build_skb(head, headroom, len, 0);
 441         if (!skb) {
 442                 xdp_return_frame(frame);
 443                 goto err;
 444         }
 445
 446         xdp_scrub_frame(frame);
 447         skb->protocol = eth_type_trans(skb, rq->dev);
 448 err:
 449         return skb;
 450 err_xdp:
 451         rcu_read_unlock();
 452         xdp_return_frame(frame);
 453 xdp_xmit:
 454         return NULL;
 455 }
 456
 457 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq, struct sk_buff *skb,
 458                                         unsigned int *xdp_xmit)
 459 {
 460         u32 pktlen, headroom, act, metalen;
 461         void *orig_data, *orig_data_end;
 462         struct bpf_prog *xdp_prog;
 463         int mac_len, delta, off;
 464         struct xdp_buff xdp;
 465
 466         rcu_read_lock();
 467         xdp_prog = rcu_dereference(rq->xdp_prog);
 468         if (unlikely(!xdp_prog)) {
 469                 rcu_read_unlock();
 470                 goto out;
 471         }
 472
 473         mac_len = skb->data - skb_mac_header(skb);
 474         pktlen = skb->len + mac_len;
 475         headroom = skb_headroom(skb) - mac_len;
 476
 477         if (skb_shared(skb) || skb_head_is_locked(skb) ||
 478             skb_is_nonlinear(skb) || headroom < XDP_PACKET_HEADROOM) {
 479                 struct sk_buff *nskb;
 480                 int size, head_off;
 481                 void *head, *start;
 482                 struct page *page;
 483
 484                 size = SKB_DATA_ALIGN(VETH_XDP_HEADROOM + pktlen) +
 485                        SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 486                 if (size > PAGE_SIZE)
 487                         goto drop;
 488
 489                 page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 490                 if (!page)
 491                         goto drop;
 492
 493                 head = page_address(page);
 494                 start = head + VETH_XDP_HEADROOM;
 495                 if (skb_copy_bits(skb, -mac_len, start, pktlen)) {
 496                         page_frag_free(head);
 497                         goto drop;
 498                 }
 499
 500                 nskb = veth_build_skb(head,
 501                                       VETH_XDP_HEADROOM + mac_len, skb->len,
 502                                       PAGE_SIZE);
 503                 if (!nskb) {
 504                         page_frag_free(head);
 505                         goto drop;
 506                 }
 507
 508                 skb_copy_header(nskb, skb);
 509                 head_off = skb_headroom(nskb) - skb_headroom(skb);
 510                 skb_headers_offset_update(nskb, head_off);
 511                 if (skb->sk)
 512                         skb_set_owner_w(nskb, skb->sk);
 513                 consume_skb(skb);
 514                 skb = nskb;
 515         }
 516
 517         xdp.data_hard_start = skb->head;
 518         xdp.data = skb_mac_header(skb);
 519         xdp.data_end = xdp.data + pktlen;
 520         xdp.data_meta = xdp.data;
 521         xdp.rxq = &rq->xdp_rxq;
 522         orig_data = xdp.data;
 523         orig_data_end = xdp.data_end;
 524
 525         act = bpf_prog_run_xdp(xdp_prog, &xdp);
 526
 527         switch (act) {
 528         case XDP_PASS:
 529                 break;
 530         case XDP_TX:
 531                 get_page(virt_to_page(xdp.data));
 532                 consume_skb(skb);
 533                 xdp.rxq->mem = rq->xdp_mem;
 534                 if (unlikely(veth_xdp_tx(rq->dev, &xdp) < 0)) {
 535                         trace_xdp_exception(rq->dev, xdp_prog, act);
 536                         goto err_xdp;
 537                 }
 538                 *xdp_xmit |= VETH_XDP_TX;
 539                 rcu_read_unlock();
 540                 goto xdp_xmit;
 541         case XDP_REDIRECT:
 542                 get_page(virt_to_page(xdp.data));
 543                 consume_skb(skb);
 544                 xdp.rxq->mem = rq->xdp_mem;
 545                 if (xdp_do_redirect(rq->dev, &xdp, xdp_prog))
 546                         goto err_xdp;
 547                 *xdp_xmit |= VETH_XDP_REDIR;
 548                 rcu_read_unlock();
 549                 goto xdp_xmit;
 550         default:
 551                 bpf_warn_invalid_xdp_action(act);
 552         case XDP_ABORTED:
 553                 trace_xdp_exception(rq->dev, xdp_prog, act);
 554         case XDP_DROP:
 555                 goto drop;
 556         }
 557         rcu_read_unlock();
 558
 559         delta = orig_data - xdp.data;
 560         off = mac_len + delta;
 561         if (off > 0)
 562                 __skb_push(skb, off);
 563         else if (off < 0)
 564                 __skb_pull(skb, -off);
 565         skb->mac_header -= delta;
 566         off = xdp.data_end - orig_data_end;
 567         if (off != 0)
 568                 __skb_put(skb, off);
 569         skb->protocol = eth_type_trans(skb, rq->dev);
 570
 571         metalen = xdp.data - xdp.data_meta;
 572         if (metalen)
 573                 skb_metadata_set(skb, metalen);
 574 out:
 575         return skb;
 576 drop:
 577         rcu_read_unlock();
 578         kfree_skb(skb);
 579         return NULL;
 580 err_xdp:
 581         rcu_read_unlock();
 582         page_frag_free(xdp.data);
 583 xdp_xmit:
 584         return NULL;
 585 }
 586
 587 static int veth_xdp_rcv(struct veth_rq *rq, int budget, unsigned int *xdp_xmit)
 588 {
 589         int i, done = 0;
 590
 591         for (i = 0; i < budget; i++) {
 592                 void *ptr = __ptr_ring_consume(&rq->xdp_ring);
 593                 struct sk_buff *skb;
 594
 595                 if (!ptr)
 596                         break;
 597
 598                 if (veth_is_xdp_frame(ptr)) {
 599                         skb = veth_xdp_rcv_one(rq, veth_ptr_to_xdp(ptr),
 600                                                xdp_xmit);
 601                 } else {
 602                         skb = veth_xdp_rcv_skb(rq, ptr, xdp_xmit);
 603                 }
 604
 605                 if (skb)
 606                         napi_gro_receive(&rq->xdp_napi, skb);
 607
 608                 done++;
 609         }
 610
 611         return done;
 612 }
 613
 614 static int veth_poll(struct napi_struct *napi, int budget)
 615 {
 616         struct veth_rq *rq =
 617                 container_of(napi, struct veth_rq, xdp_napi);
 618         unsigned int xdp_xmit = 0;
 619         int done;
 620
 621         xdp_set_return_frame_no_direct();
 622         done = veth_xdp_rcv(rq, budget, &xdp_xmit);
 623
 624         if (done < budget && napi_complete_done(napi, done)) {
 625                 /* Write rx_notify_masked before reading ptr_ring */
 626                 smp_store_mb(rq->rx_notify_masked, false);
 627                 if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
 628                         rq->rx_notify_masked = true;
 629                         napi_schedule(&rq->xdp_napi);
 630                 }
 631         }
 632
 633         if (xdp_xmit & VETH_XDP_TX)
 634                 veth_xdp_flush(rq->dev);
 635         if (xdp_xmit & VETH_XDP_REDIR)
 636                 xdp_do_flush_map();
 637         xdp_clear_return_frame_no_direct();
 638
 639         return done;
 640 }
 641
 642 static int veth_napi_add(struct net_device *dev)
 643 {
 644         struct veth_priv *priv = netdev_priv(dev);
 645         int err, i;
 646
 647         for (i = 0; i < dev->real_num_rx_queues; i++) {
 648                 struct veth_rq *rq = &priv->rq[i];
 649
 650                 err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
 651                 if (err)
 652                         goto err_xdp_ring;
 653         }
 654
 655         for (i = 0; i < dev->real_num_rx_queues; i++) {
 656                 struct veth_rq *rq = &priv->rq[i];
 657
 658                 netif_napi_add(dev, &rq->xdp_napi, veth_poll, NAPI_POLL_WEIGHT);
 659                 napi_enable(&rq->xdp_napi);
 660         }
 661
 662         return 0;
 663 err_xdp_ring:
 664         for (i--; i >= 0; i--)
 665                 ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
 666
 667         return err;
 668 }
 669
 670 static void veth_napi_del(struct net_device *dev)
 671 {
 672         struct veth_priv *priv = netdev_priv(dev);
 673         int i;
 674
 675         for (i = 0; i < dev->real_num_rx_queues; i++) {
 676                 struct veth_rq *rq = &priv->rq[i];
 677
 678                 napi_disable(&rq->xdp_napi);
 679                 napi_hash_del(&rq->xdp_napi);
 680         }
 681         synchronize_net();
 682
 683         for (i = 0; i < dev->real_num_rx_queues; i++) {
 684                 struct veth_rq *rq = &priv->rq[i];
 685
 686                 netif_napi_del(&rq->xdp_napi);
 687                 rq->rx_notify_masked = false;
 688                 ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
 689         }
 690 }
 691
 692 static int veth_enable_xdp(struct net_device *dev)
 693 {
 694         struct veth_priv *priv = netdev_priv(dev);
 695         int err, i;
 696
 697         if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
 698                 for (i = 0; i < dev->real_num_rx_queues; i++) {
 699                         struct veth_rq *rq = &priv->rq[i];
 700
 701                         err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i);
 702                         if (err < 0)
 703                                 goto err_rxq_reg;
 704
 705                         err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
 706                                                          MEM_TYPE_PAGE_SHARED,
 707                                                          NULL);
 708                         if (err < 0)
 709                                 goto err_reg_mem;
 710
 711                         /* Save original mem info as it can be overwritten */
 712                         rq->xdp_mem = rq->xdp_rxq.mem;
 713                 }
 714
 715                 err = veth_napi_add(dev);
 716                 if (err)
 717                         goto err_rxq_reg;
 718         }
 719
 720         for (i = 0; i < dev->real_num_rx_queues; i++)
 721                 rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
 722
 723         return 0;
 724 err_reg_mem:
 725         xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 726 err_rxq_reg:
 727         for (i--; i >= 0; i--)
 728                 xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
 729
 730         return err;
 731 }
 732
 733 static void veth_disable_xdp(struct net_device *dev)
 734 {
 735         struct veth_priv *priv = netdev_priv(dev);
 736         int i;
 737
 738         for (i = 0; i < dev->real_num_rx_queues; i++)
 739                 rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
 740         veth_napi_del(dev);
 741         for (i = 0; i < dev->real_num_rx_queues; i++) {
 742                 struct veth_rq *rq = &priv->rq[i];
 743
 744                 rq->xdp_rxq.mem = rq->xdp_mem;
 745                 xdp_rxq_info_unreg(&rq->xdp_rxq);
 746         }
 747 }
 748
 749 static int veth_open(struct net_device *dev)
 750 {
 751         struct veth_priv *priv = netdev_priv(dev);
 752         struct net_device *peer = rtnl_dereference(priv->peer);
 753         int err;
 754
 755         if (!peer)
 756                 return -ENOTCONN;
 757
 758         if (priv->_xdp_prog) {
 759                 err = veth_enable_xdp(dev);
 760                 if (err)
 761                         return err;
 762         }
 763
 764         if (peer->flags & IFF_UP) {
 765                 netif_carrier_on(dev);
 766                 netif_carrier_on(peer);
 767         }
 768
 769         return 0;
 770 }
 771
 772 static int veth_close(struct net_device *dev)
 773 {
 774         struct veth_priv *priv = netdev_priv(dev);
 775         struct net_device *peer = rtnl_dereference(priv->peer);
 776
 777         netif_carrier_off(dev);
 778         if (peer)
 779                 netif_carrier_off(peer);
 780
 781         if (priv->_xdp_prog)
 782                 veth_disable_xdp(dev);
 783
 784         return 0;
 785 }
 786
 787 static int is_valid_veth_mtu(int mtu)
 788 {
 789         return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
 790 }
 791
 792 static int veth_dev_init(struct net_device *dev)
 793 {
 794         dev->vstats = netdev_alloc_pcpu_stats(struct pcpu_vstats);
 795         if (!dev->vstats)
 796                 return -ENOMEM;
 797         return 0;
 798 }
 799
 800 static void veth_dev_free(struct net_device *dev)
 801 {
 802         free_percpu(dev->vstats);
 803 }
 804
 805 #ifdef CONFIG_NET_POLL_CONTROLLER
 806 static void veth_poll_controller(struct net_device *dev)
 807 {
 808         /* veth only receives frames when its peer sends one
 809          * Since it has nothing to do with disabling irqs, we are guaranteed
 810          * never to have pending data when we poll for it so
 811          * there is nothing to do here.
 812          *
 813          * We need this though so netpoll recognizes us as an interface that
 814          * supports polling, which enables bridge devices in virt setups to
 815          * still use netconsole
 816          */
 817 }
 818 #endif  /* CONFIG_NET_POLL_CONTROLLER */
 819
 820 static int veth_get_iflink(const struct net_device *dev)
 821 {
 822         struct veth_priv *priv = netdev_priv(dev);
 823         struct net_device *peer;
 824         int iflink;
 825
 826         rcu_read_lock();
 827         peer = rcu_dereference(priv->peer);
 828         iflink = peer ? peer->ifindex : 0;
 829         rcu_read_unlock();
 830
 831         return iflink;
 832 }
 833
 834 static netdev_features_t veth_fix_features(struct net_device *dev,
 835                                            netdev_features_t features)
 836 {
 837         struct veth_priv *priv = netdev_priv(dev);
 838         struct net_device *peer;
 839
 840         peer = rtnl_dereference(priv->peer);
 841         if (peer) {
 842                 struct veth_priv *peer_priv = netdev_priv(peer);
 843
 844                 if (peer_priv->_xdp_prog)
 845                         features &= ~NETIF_F_GSO_SOFTWARE;
 846         }
 847
 848         return features;
 849 }
 850
 851 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
 852 {
 853         struct veth_priv *peer_priv, *priv = netdev_priv(dev);
 854         struct net_device *peer;
 855
 856         if (new_hr < 0)
 857                 new_hr = 0;
 858
 859         rcu_read_lock();
 860         peer = rcu_dereference(priv->peer);
 861         if (unlikely(!peer))
 862                 goto out;
 863
 864         peer_priv = netdev_priv(peer);
 865         priv->requested_headroom = new_hr;
 866         new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
 867         dev->needed_headroom = new_hr;
 868         peer->needed_headroom = new_hr;
 869
 870 out:
 871         rcu_read_unlock();
 872 }
 873
 874 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
 875                         struct netlink_ext_ack *extack)
 876 {
 877         struct veth_priv *priv = netdev_priv(dev);
 878         struct bpf_prog *old_prog;
 879         struct net_device *peer;
 880         unsigned int max_mtu;
 881         int err;
 882
 883         old_prog = priv->_xdp_prog;
 884         priv->_xdp_prog = prog;
 885         peer = rtnl_dereference(priv->peer);
 886
 887         if (prog) {
 888                 if (!peer) {
 889                         NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
 890                         err = -ENOTCONN;
 891                         goto err;
 892                 }
 893
 894                 max_mtu = PAGE_SIZE - VETH_XDP_HEADROOM -
 895                           peer->hard_header_len -
 896                           SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 897                 if (peer->mtu > max_mtu) {
 898                         NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
 899                         err = -ERANGE;
 900                         goto err;
 901                 }
 902
 903                 if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
 904                         NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
 905                         err = -ENOSPC;
 906                         goto err;
 907                 }
 908
 909                 if (dev->flags & IFF_UP) {
 910                         err = veth_enable_xdp(dev);
 911                         if (err) {
 912                                 NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
 913                                 goto err;
 914                         }
 915                 }
 916
 917                 if (!old_prog) {
 918                         peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
 919                         peer->max_mtu = max_mtu;
 920                 }
 921         }
 922
 923         if (old_prog) {
 924                 if (!prog) {
 925                         if (dev->flags & IFF_UP)
 926                                 veth_disable_xdp(dev);
 927
 928                         if (peer) {
 929                                 peer->hw_features |= NETIF_F_GSO_SOFTWARE;
 930                                 peer->max_mtu = ETH_MAX_MTU;
 931                         }
 932                 }
 933                 bpf_prog_put(old_prog);
 934         }
 935
 936         if ((!!old_prog ^ !!prog) && peer)
 937                 netdev_update_features(peer);
 938
 939         return 0;
 940 err:
 941         priv->_xdp_prog = old_prog;
 942
 943         return err;
 944 }
 945
 946 static u32 veth_xdp_query(struct net_device *dev)
 947 {
 948         struct veth_priv *priv = netdev_priv(dev);
 949         const struct bpf_prog *xdp_prog;
 950
 951         xdp_prog = priv->_xdp_prog;
 952         if (xdp_prog)
 953                 return xdp_prog->aux->id;
 954
 955         return 0;
 956 }
 957
 958 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
 959 {
 960         switch (xdp->command) {
 961         case XDP_SETUP_PROG:
 962                 return veth_xdp_set(dev, xdp->prog, xdp->extack);
 963         case XDP_QUERY_PROG:
 964                 xdp->prog_id = veth_xdp_query(dev);
 965                 return 0;
 966         default:
 967                 return -EINVAL;
 968         }
 969 }
 970
 971 static const struct net_device_ops veth_netdev_ops = {
 972         .ndo_init            = veth_dev_init,
 973         .ndo_open            = veth_open,
 974         .ndo_stop            = veth_close,
 975         .ndo_start_xmit      = veth_xmit,
 976         .ndo_get_stats64     = veth_get_stats64,
 977         .ndo_set_rx_mode     = veth_set_multicast_list,
 978         .ndo_set_mac_address = eth_mac_addr,
 979 #ifdef CONFIG_NET_POLL_CONTROLLER
 980         .ndo_poll_controller    = veth_poll_controller,
 981 #endif
 982         .ndo_get_iflink         = veth_get_iflink,
 983         .ndo_fix_features       = veth_fix_features,
 984         .ndo_features_check     = passthru_features_check,
 985         .ndo_set_rx_headroom    = veth_set_rx_headroom,
 986         .ndo_bpf                = veth_xdp,
 987         .ndo_xdp_xmit           = veth_xdp_xmit,
 988 };
 989
 990 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
 991                        NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
 992                        NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
 993                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
 994                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
 995
 996 static void veth_setup(struct net_device *dev)
 997 {
 998         ether_setup(dev);
 999
1000         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1001         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1002         dev->priv_flags |= IFF_NO_QUEUE;
1003         dev->priv_flags |= IFF_PHONY_HEADROOM;
1004
1005         dev->netdev_ops = &veth_netdev_ops;
1006         dev->ethtool_ops = &veth_ethtool_ops;
1007         dev->features |= NETIF_F_LLTX;
1008         dev->features |= VETH_FEATURES;
1009         dev->vlan_features = dev->features &
1010                              ~(NETIF_F_HW_VLAN_CTAG_TX |
1011                                NETIF_F_HW_VLAN_STAG_TX |
1012                                NETIF_F_HW_VLAN_CTAG_RX |
1013                                NETIF_F_HW_VLAN_STAG_RX);
1014         dev->needs_free_netdev = true;
1015         dev->priv_destructor = veth_dev_free;
1016         dev->max_mtu = ETH_MAX_MTU;
1017
1018         dev->hw_features = VETH_FEATURES;
1019         dev->hw_enc_features = VETH_FEATURES;
1020         dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1021 }
1022
1023 /*
1024  * netlink interface
1025  */
1026
1027 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1028                          struct netlink_ext_ack *extack)
1029 {
1030         if (tb[IFLA_ADDRESS]) {
1031                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1032                         return -EINVAL;
1033                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1034                         return -EADDRNOTAVAIL;
1035         }
1036         if (tb[IFLA_MTU]) {
1037                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1038                         return -EINVAL;
1039         }
1040         return 0;
1041 }
1042
1043 static int veth_alloc_queues(struct net_device *dev)
1044 {
1045         struct veth_priv *priv = netdev_priv(dev);
1046
1047         priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL);
1048         if (!priv->rq)
1049                 return -ENOMEM;
1050
1051         return 0;
1052 }
1053
1054 static void veth_free_queues(struct net_device *dev)
1055 {
1056         struct veth_priv *priv = netdev_priv(dev);
1057
1058         kfree(priv->rq);
1059 }
1060
1061 static struct rtnl_link_ops veth_link_ops;
1062
1063 static int veth_newlink(struct net *src_net, struct net_device *dev,
1064                         struct nlattr *tb[], struct nlattr *data[],
1065                         struct netlink_ext_ack *extack)
1066 {
1067         int err, i;
1068         struct net_device *peer;
1069         struct veth_priv *priv;
1070         char ifname[IFNAMSIZ];
1071         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1072         unsigned char name_assign_type;
1073         struct ifinfomsg *ifmp;
1074         struct net *net;
1075
1076         /*
1077          * create and register peer first
1078          */
1079         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1080                 struct nlattr *nla_peer;
1081
1082                 nla_peer = data[VETH_INFO_PEER];
1083                 ifmp = nla_data(nla_peer);
1084                 err = rtnl_nla_parse_ifla(peer_tb,
1085                                           nla_data(nla_peer) + sizeof(struct ifinfomsg),
1086                                           nla_len(nla_peer) - sizeof(struct ifinfomsg),
1087                                           NULL);
1088                 if (err < 0)
1089                         return err;
1090
1091                 err = veth_validate(peer_tb, NULL, extack);
1092                 if (err < 0)
1093                         return err;
1094
1095                 tbp = peer_tb;
1096         } else {
1097                 ifmp = NULL;
1098                 tbp = tb;
1099         }
1100
1101         if (ifmp && tbp[IFLA_IFNAME]) {
1102                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1103                 name_assign_type = NET_NAME_USER;
1104         } else {
1105                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1106                 name_assign_type = NET_NAME_ENUM;
1107         }
1108
1109         net = rtnl_link_get_net(src_net, tbp);
1110         if (IS_ERR(net))
1111                 return PTR_ERR(net);
1112
1113         peer = rtnl_create_link(net, ifname, name_assign_type,
1114                                 &veth_link_ops, tbp);
1115         if (IS_ERR(peer)) {
1116                 put_net(net);
1117                 return PTR_ERR(peer);
1118         }
1119
1120         err = veth_alloc_queues(peer);
1121         if (err) {
1122                 put_net(net);
1123                 goto err_peer_alloc_queues;
1124         }
1125
1126         if (!ifmp || !tbp[IFLA_ADDRESS])
1127                 eth_hw_addr_random(peer);
1128
1129         if (ifmp && (dev->ifindex != 0))
1130                 peer->ifindex = ifmp->ifi_index;
1131
1132         peer->gso_max_size = dev->gso_max_size;
1133         peer->gso_max_segs = dev->gso_max_segs;
1134
1135         err = register_netdevice(peer);
1136         put_net(net);
1137         net = NULL;
1138         if (err < 0)
1139                 goto err_register_peer;
1140
1141         netif_carrier_off(peer);
1142
1143         err = rtnl_configure_link(peer, ifmp);
1144         if (err < 0)
1145                 goto err_configure_peer;
1146
1147         /*
1148          * register dev last
1149          *
1150          * note, that since we've registered new device the dev's name
1151          * should be re-allocated
1152          */
1153
1154         err = veth_alloc_queues(dev);
1155         if (err)
1156                 goto err_alloc_queues;
1157
1158         if (tb[IFLA_ADDRESS] == NULL)
1159                 eth_hw_addr_random(dev);
1160
1161         if (tb[IFLA_IFNAME])
1162                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1163         else
1164                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1165
1166         err = register_netdevice(dev);
1167         if (err < 0)
1168                 goto err_register_dev;
1169
1170         netif_carrier_off(dev);
1171
1172         /*
1173          * tie the deviced together
1174          */
1175
1176         priv = netdev_priv(dev);
1177         for (i = 0; i < dev->real_num_rx_queues; i++)
1178                 priv->rq[i].dev = dev;
1179         rcu_assign_pointer(priv->peer, peer);
1180
1181         priv = netdev_priv(peer);
1182         for (i = 0; i < peer->real_num_rx_queues; i++)
1183                 priv->rq[i].dev = peer;
1184         rcu_assign_pointer(priv->peer, dev);
1185
1186         return 0;
1187
1188 err_register_dev:
1189         veth_free_queues(dev);
1190 err_alloc_queues:
1191         /* nothing to do */
1192 err_configure_peer:
1193         unregister_netdevice(peer);
1194         return err;
1195
1196 err_register_peer:
1197         veth_free_queues(peer);
1198 err_peer_alloc_queues:
1199         free_netdev(peer);
1200         return err;
1201 }
1202
1203 static void veth_dellink(struct net_device *dev, struct list_head *head)
1204 {
1205         struct veth_priv *priv;
1206         struct net_device *peer;
1207
1208         priv = netdev_priv(dev);
1209         peer = rtnl_dereference(priv->peer);
1210
1211         /* Note : dellink() is called from default_device_exit_batch(),
1212          * before a rcu_synchronize() point. The devices are guaranteed
1213          * not being freed before one RCU grace period.
1214          */
1215         RCU_INIT_POINTER(priv->peer, NULL);
1216         unregister_netdevice_queue(dev, head);
1217
1218         if (peer) {
1219                 priv = netdev_priv(peer);
1220                 RCU_INIT_POINTER(priv->peer, NULL);
1221                 unregister_netdevice_queue(peer, head);
1222         }
1223 }
1224
1225 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1226         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
1227 };
1228
1229 static struct net *veth_get_link_net(const struct net_device *dev)
1230 {
1231         struct veth_priv *priv = netdev_priv(dev);
1232         struct net_device *peer = rtnl_dereference(priv->peer);
1233
1234         return peer ? dev_net(peer) : dev_net(dev);
1235 }
1236
1237 static struct rtnl_link_ops veth_link_ops = {
1238         .kind           = DRV_NAME,
1239         .priv_size      = sizeof(struct veth_priv),
1240         .setup          = veth_setup,
1241         .validate       = veth_validate,
1242         .newlink        = veth_newlink,
1243         .dellink        = veth_dellink,
1244         .policy         = veth_policy,
1245         .maxtype        = VETH_INFO_MAX,
1246         .get_link_net   = veth_get_link_net,
1247 };
1248
1249 /*
1250  * init/fini
1251  */
1252
1253 static __init int veth_init(void)
1254 {
1255         return rtnl_link_register(&veth_link_ops);
1256 }
1257
1258 static __exit void veth_exit(void)
1259 {
1260         rtnl_link_unregister(&veth_link_ops);
1261 }
1262
1263 module_init(veth_init);
1264 module_exit(veth_exit);
1265
1266 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1267 MODULE_LICENSE("GPL v2");
1268 MODULE_ALIAS_RTNL_LINK(DRV_NAME);