net/xdp/xsk.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* XDP sockets
   3  *
   4  * AF_XDP sockets allows a channel between XDP programs and userspace
   5  * applications.
   6  * Copyright(c) 2018 Intel Corporation.
   7  *
   8  * Author(s): Björn Töpel <bjorn.topel@intel.com>
   9  *            Magnus Karlsson <magnus.karlsson@intel.com>
  10  */
  11
  12 #define pr_fmt(fmt) "AF_XDP: %s: " fmt, __func__
  13
  14 #include <linux/if_xdp.h>
  15 #include <linux/init.h>
  16 #include <linux/sched/mm.h>
  17 #include <linux/sched/signal.h>
  18 #include <linux/sched/task.h>
  19 #include <linux/socket.h>
  20 #include <linux/file.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/net.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/rculist.h>
  25 #include <net/xdp_sock.h>
  26 #include <net/xdp.h>
  27
  28 #include "xsk_queue.h"
  29 #include "xdp_umem.h"
  30 #include "xsk.h"
  31
  32 #define TX_BATCH_SIZE 16
  33
  34 bool xsk_is_setup_for_bpf_map(struct xdp_sock *xs)
  35 {
  36         return READ_ONCE(xs->rx) &&  READ_ONCE(xs->umem) &&
  37                 READ_ONCE(xs->umem->fq);
  38 }
  39
  40 u64 *xsk_umem_peek_addr(struct xdp_umem *umem, u64 *addr)
  41 {
  42         return xskq_peek_addr(umem->fq, addr);
  43 }
  44 EXPORT_SYMBOL(xsk_umem_peek_addr);
  45
  46 void xsk_umem_discard_addr(struct xdp_umem *umem)
  47 {
  48         xskq_discard_addr(umem->fq);
  49 }
  50 EXPORT_SYMBOL(xsk_umem_discard_addr);
  51
  52 static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
  53 {
  54         void *to_buf, *from_buf;
  55         u32 metalen;
  56         u64 addr;
  57         int err;
  58
  59         if (!xskq_peek_addr(xs->umem->fq, &addr) ||
  60             len > xs->umem->chunk_size_nohr - XDP_PACKET_HEADROOM) {
  61                 xs->rx_dropped++;
  62                 return -ENOSPC;
  63         }
  64
  65         addr += xs->umem->headroom;
  66
  67         if (unlikely(xdp_data_meta_unsupported(xdp))) {
  68                 from_buf = xdp->data;
  69                 metalen = 0;
  70         } else {
  71                 from_buf = xdp->data_meta;
  72                 metalen = xdp->data - xdp->data_meta;
  73         }
  74
  75         to_buf = xdp_umem_get_data(xs->umem, addr);
  76         memcpy(to_buf, from_buf, len + metalen);
  77         addr += metalen;
  78         err = xskq_produce_batch_desc(xs->rx, addr, len);
  79         if (!err) {
  80                 xskq_discard_addr(xs->umem->fq);
  81                 xdp_return_buff(xdp);
  82                 return 0;
  83         }
  84
  85         xs->rx_dropped++;
  86         return err;
  87 }
  88
  89 static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
  90 {
  91         int err = xskq_produce_batch_desc(xs->rx, (u64)xdp->handle, len);
  92
  93         if (err)
  94                 xs->rx_dropped++;
  95
  96         return err;
  97 }
  98
  99 int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 100 {
 101         u32 len;
 102
 103         if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
 104                 return -EINVAL;
 105
 106         len = xdp->data_end - xdp->data;
 107
 108         return (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY) ?
 109                 __xsk_rcv_zc(xs, xdp, len) : __xsk_rcv(xs, xdp, len);
 110 }
 111
 112 void xsk_flush(struct xdp_sock *xs)
 113 {
 114         xskq_produce_flush_desc(xs->rx);
 115         xs->sk.sk_data_ready(&xs->sk);
 116 }
 117
 118 int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 119 {
 120         u32 metalen = xdp->data - xdp->data_meta;
 121         u32 len = xdp->data_end - xdp->data;
 122         void *buffer;
 123         u64 addr;
 124         int err;
 125
 126         if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
 127                 return -EINVAL;
 128
 129         if (!xskq_peek_addr(xs->umem->fq, &addr) ||
 130             len > xs->umem->chunk_size_nohr - XDP_PACKET_HEADROOM) {
 131                 xs->rx_dropped++;
 132                 return -ENOSPC;
 133         }
 134
 135         addr += xs->umem->headroom;
 136
 137         buffer = xdp_umem_get_data(xs->umem, addr);
 138         memcpy(buffer, xdp->data_meta, len + metalen);
 139         addr += metalen;
 140         err = xskq_produce_batch_desc(xs->rx, addr, len);
 141         if (!err) {
 142                 xskq_discard_addr(xs->umem->fq);
 143                 xsk_flush(xs);
 144                 return 0;
 145         }
 146
 147         xs->rx_dropped++;
 148         return err;
 149 }
 150
 151 void xsk_umem_complete_tx(struct xdp_umem *umem, u32 nb_entries)
 152 {
 153         xskq_produce_flush_addr_n(umem->cq, nb_entries);
 154 }
 155 EXPORT_SYMBOL(xsk_umem_complete_tx);
 156
 157 void xsk_umem_consume_tx_done(struct xdp_umem *umem)
 158 {
 159         struct xdp_sock *xs;
 160
 161         rcu_read_lock();
 162         list_for_each_entry_rcu(xs, &umem->xsk_list, list) {
 163                 xs->sk.sk_write_space(&xs->sk);
 164         }
 165         rcu_read_unlock();
 166 }
 167 EXPORT_SYMBOL(xsk_umem_consume_tx_done);
 168
 169 bool xsk_umem_consume_tx(struct xdp_umem *umem, dma_addr_t *dma, u32 *len)
 170 {
 171         struct xdp_desc desc;
 172         struct xdp_sock *xs;
 173
 174         rcu_read_lock();
 175         list_for_each_entry_rcu(xs, &umem->xsk_list, list) {
 176                 if (!xskq_peek_desc(xs->tx, &desc))
 177                         continue;
 178
 179                 if (xskq_produce_addr_lazy(umem->cq, desc.addr))
 180                         goto out;
 181
 182                 *dma = xdp_umem_get_dma(umem, desc.addr);
 183                 *len = desc.len;
 184
 185                 xskq_discard_desc(xs->tx);
 186                 rcu_read_unlock();
 187                 return true;
 188         }
 189
 190 out:
 191         rcu_read_unlock();
 192         return false;
 193 }
 194 EXPORT_SYMBOL(xsk_umem_consume_tx);
 195
 196 static int xsk_zc_xmit(struct sock *sk)
 197 {
 198         struct xdp_sock *xs = xdp_sk(sk);
 199         struct net_device *dev = xs->dev;
 200
 201         return dev->netdev_ops->ndo_xsk_async_xmit(dev, xs->queue_id);
 202 }
 203
 204 static void xsk_destruct_skb(struct sk_buff *skb)
 205 {
 206         u64 addr = (u64)(long)skb_shinfo(skb)->destructor_arg;
 207         struct xdp_sock *xs = xdp_sk(skb->sk);
 208         unsigned long flags;
 209
 210         spin_lock_irqsave(&xs->tx_completion_lock, flags);
 211         WARN_ON_ONCE(xskq_produce_addr(xs->umem->cq, addr));
 212         spin_unlock_irqrestore(&xs->tx_completion_lock, flags);
 213
 214         sock_wfree(skb);
 215 }
 216
 217 static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
 218                             size_t total_len)
 219 {
 220         u32 max_batch = TX_BATCH_SIZE;
 221         struct xdp_sock *xs = xdp_sk(sk);
 222         bool sent_frame = false;
 223         struct xdp_desc desc;
 224         struct sk_buff *skb;
 225         int err = 0;
 226
 227         mutex_lock(&xs->mutex);
 228
 229         while (xskq_peek_desc(xs->tx, &desc)) {
 230                 char *buffer;
 231                 u64 addr;
 232                 u32 len;
 233
 234                 if (max_batch-- == 0) {
 235                         err = -EAGAIN;
 236                         goto out;
 237                 }
 238
 239                 if (xskq_reserve_addr(xs->umem->cq))
 240                         goto out;
 241
 242                 if (xs->queue_id >= xs->dev->real_num_tx_queues)
 243                         goto out;
 244
 245                 len = desc.len;
 246                 skb = sock_alloc_send_skb(sk, len, 1, &err);
 247                 if (unlikely(!skb)) {
 248                         err = -EAGAIN;
 249                         goto out;
 250                 }
 251
 252                 skb_put(skb, len);
 253                 addr = desc.addr;
 254                 buffer = xdp_umem_get_data(xs->umem, addr);
 255                 err = skb_store_bits(skb, 0, buffer, len);
 256                 if (unlikely(err)) {
 257                         kfree_skb(skb);
 258                         goto out;
 259                 }
 260
 261                 skb->dev = xs->dev;
 262                 skb->priority = sk->sk_priority;
 263                 skb->mark = sk->sk_mark;
 264                 skb_shinfo(skb)->destructor_arg = (void *)(long)addr;
 265                 skb->destructor = xsk_destruct_skb;
 266
 267                 err = dev_direct_xmit(skb, xs->queue_id);
 268                 xskq_discard_desc(xs->tx);
 269                 /* Ignore NET_XMIT_CN as packet might have been sent */
 270                 if (err == NET_XMIT_DROP || err == NETDEV_TX_BUSY) {
 271                         /* SKB completed but not sent */
 272                         err = -EBUSY;
 273                         goto out;
 274                 }
 275
 276                 sent_frame = true;
 277         }
 278
 279 out:
 280         if (sent_frame)
 281                 sk->sk_write_space(sk);
 282
 283         mutex_unlock(&xs->mutex);
 284         return err;
 285 }
 286
 287 static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 288 {
 289         bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
 290         struct sock *sk = sock->sk;
 291         struct xdp_sock *xs = xdp_sk(sk);
 292
 293         if (unlikely(!xs->dev))
 294                 return -ENXIO;
 295         if (unlikely(!(xs->dev->flags & IFF_UP)))
 296                 return -ENETDOWN;
 297         if (unlikely(!xs->tx))
 298                 return -ENOBUFS;
 299         if (need_wait)
 300                 return -EOPNOTSUPP;
 301
 302         return (xs->zc) ? xsk_zc_xmit(sk) : xsk_generic_xmit(sk, m, total_len);
 303 }
 304
 305 static unsigned int xsk_poll(struct file *file, struct socket *sock,
 306                              struct poll_table_struct *wait)
 307 {
 308         unsigned int mask = datagram_poll(file, sock, wait);
 309         struct sock *sk = sock->sk;
 310         struct xdp_sock *xs = xdp_sk(sk);
 311
 312         if (xs->rx && !xskq_empty_desc(xs->rx))
 313                 mask |= POLLIN | POLLRDNORM;
 314         if (xs->tx && !xskq_full_desc(xs->tx))
 315                 mask |= POLLOUT | POLLWRNORM;
 316
 317         return mask;
 318 }
 319
 320 static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
 321                           bool umem_queue)
 322 {
 323         struct xsk_queue *q;
 324
 325         if (entries == 0 || *queue || !is_power_of_2(entries))
 326                 return -EINVAL;
 327
 328         q = xskq_create(entries, umem_queue);
 329         if (!q)
 330                 return -ENOMEM;
 331
 332         /* Make sure queue is ready before it can be seen by others */
 333         smp_wmb();
 334         *queue = q;
 335         return 0;
 336 }
 337
 338 static int xsk_release(struct socket *sock)
 339 {
 340         struct sock *sk = sock->sk;
 341         struct xdp_sock *xs = xdp_sk(sk);
 342         struct net *net;
 343
 344         if (!sk)
 345                 return 0;
 346
 347         net = sock_net(sk);
 348
 349         mutex_lock(&net->xdp.lock);
 350         sk_del_node_init_rcu(sk);
 351         mutex_unlock(&net->xdp.lock);
 352
 353         local_bh_disable();
 354         sock_prot_inuse_add(net, sk->sk_prot, -1);
 355         local_bh_enable();
 356
 357         if (xs->dev) {
 358                 struct net_device *dev = xs->dev;
 359
 360                 /* Wait for driver to stop using the xdp socket. */
 361                 xdp_del_sk_umem(xs->umem, xs);
 362                 xs->dev = NULL;
 363                 synchronize_net();
 364                 dev_put(dev);
 365         }
 366
 367         xskq_destroy(xs->rx);
 368         xskq_destroy(xs->tx);
 369
 370         sock_orphan(sk);
 371         sock->sk = NULL;
 372
 373         sk_refcnt_debug_release(sk);
 374         sock_put(sk);
 375
 376         return 0;
 377 }
 378
 379 static struct socket *xsk_lookup_xsk_from_fd(int fd)
 380 {
 381         struct socket *sock;
 382         int err;
 383
 384         sock = sockfd_lookup(fd, &err);
 385         if (!sock)
 386                 return ERR_PTR(-ENOTSOCK);
 387
 388         if (sock->sk->sk_family != PF_XDP) {
 389                 sockfd_put(sock);
 390                 return ERR_PTR(-ENOPROTOOPT);
 391         }
 392
 393         return sock;
 394 }
 395
 396 static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 397 {
 398         struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr;
 399         struct sock *sk = sock->sk;
 400         struct xdp_sock *xs = xdp_sk(sk);
 401         struct net_device *dev;
 402         u32 flags, qid;
 403         int err = 0;
 404
 405         if (addr_len < sizeof(struct sockaddr_xdp))
 406                 return -EINVAL;
 407         if (sxdp->sxdp_family != AF_XDP)
 408                 return -EINVAL;
 409
 410         flags = sxdp->sxdp_flags;
 411         if (flags & ~(XDP_SHARED_UMEM | XDP_COPY | XDP_ZEROCOPY))
 412                 return -EINVAL;
 413
 414         mutex_lock(&xs->mutex);
 415         if (xs->dev) {
 416                 err = -EBUSY;
 417                 goto out_release;
 418         }
 419
 420         dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);
 421         if (!dev) {
 422                 err = -ENODEV;
 423                 goto out_release;
 424         }
 425
 426         if (!xs->rx && !xs->tx) {
 427                 err = -EINVAL;
 428                 goto out_unlock;
 429         }
 430
 431         qid = sxdp->sxdp_queue_id;
 432
 433         if (flags & XDP_SHARED_UMEM) {
 434                 struct xdp_sock *umem_xs;
 435                 struct socket *sock;
 436
 437                 if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY)) {
 438                         /* Cannot specify flags for shared sockets. */
 439                         err = -EINVAL;
 440                         goto out_unlock;
 441                 }
 442
 443                 if (xs->umem) {
 444                         /* We have already our own. */
 445                         err = -EINVAL;
 446                         goto out_unlock;
 447                 }
 448
 449                 sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd);
 450                 if (IS_ERR(sock)) {
 451                         err = PTR_ERR(sock);
 452                         goto out_unlock;
 453                 }
 454
 455                 umem_xs = xdp_sk(sock->sk);
 456                 if (!umem_xs->umem) {
 457                         /* No umem to inherit. */
 458                         err = -EBADF;
 459                         sockfd_put(sock);
 460                         goto out_unlock;
 461                 } else if (umem_xs->dev != dev || umem_xs->queue_id != qid) {
 462                         err = -EINVAL;
 463                         sockfd_put(sock);
 464                         goto out_unlock;
 465                 }
 466
 467                 xdp_get_umem(umem_xs->umem);
 468                 xs->umem = umem_xs->umem;
 469                 sockfd_put(sock);
 470         } else if (!xs->umem || !xdp_umem_validate_queues(xs->umem)) {
 471                 err = -EINVAL;
 472                 goto out_unlock;
 473         } else {
 474                 /* This xsk has its own umem. */
 475                 xskq_set_umem(xs->umem->fq, xs->umem->size,
 476                               xs->umem->chunk_mask);
 477                 xskq_set_umem(xs->umem->cq, xs->umem->size,
 478                               xs->umem->chunk_mask);
 479
 480                 err = xdp_umem_assign_dev(xs->umem, dev, qid, flags);
 481                 if (err)
 482                         goto out_unlock;
 483         }
 484
 485         xs->dev = dev;
 486         xs->zc = xs->umem->zc;
 487         xs->queue_id = qid;
 488         xskq_set_umem(xs->rx, xs->umem->size, xs->umem->chunk_mask);
 489         xskq_set_umem(xs->tx, xs->umem->size, xs->umem->chunk_mask);
 490         xdp_add_sk_umem(xs->umem, xs);
 491
 492 out_unlock:
 493         if (err)
 494                 dev_put(dev);
 495 out_release:
 496         mutex_unlock(&xs->mutex);
 497         return err;
 498 }
 499
 500 static int xsk_setsockopt(struct socket *sock, int level, int optname,
 501                           char __user *optval, unsigned int optlen)
 502 {
 503         struct sock *sk = sock->sk;
 504         struct xdp_sock *xs = xdp_sk(sk);
 505         int err;
 506
 507         if (level != SOL_XDP)
 508                 return -ENOPROTOOPT;
 509
 510         switch (optname) {
 511         case XDP_RX_RING:
 512         case XDP_TX_RING:
 513         {
 514                 struct xsk_queue **q;
 515                 int entries;
 516
 517                 if (optlen < sizeof(entries))
 518                         return -EINVAL;
 519                 if (copy_from_user(&entries, optval, sizeof(entries)))
 520                         return -EFAULT;
 521
 522                 mutex_lock(&xs->mutex);
 523                 q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx;
 524                 err = xsk_init_queue(entries, q, false);
 525                 mutex_unlock(&xs->mutex);
 526                 return err;
 527         }
 528         case XDP_UMEM_REG:
 529         {
 530                 struct xdp_umem_reg mr;
 531                 struct xdp_umem *umem;
 532
 533                 if (copy_from_user(&mr, optval, sizeof(mr)))
 534                         return -EFAULT;
 535
 536                 mutex_lock(&xs->mutex);
 537                 if (xs->umem) {
 538                         mutex_unlock(&xs->mutex);
 539                         return -EBUSY;
 540                 }
 541
 542                 umem = xdp_umem_create(&mr);
 543                 if (IS_ERR(umem)) {
 544                         mutex_unlock(&xs->mutex);
 545                         return PTR_ERR(umem);
 546                 }
 547
 548                 /* Make sure umem is ready before it can be seen by others */
 549                 smp_wmb();
 550                 xs->umem = umem;
 551                 mutex_unlock(&xs->mutex);
 552                 return 0;
 553         }
 554         case XDP_UMEM_FILL_RING:
 555         case XDP_UMEM_COMPLETION_RING:
 556         {
 557                 struct xsk_queue **q;
 558                 int entries;
 559
 560                 if (copy_from_user(&entries, optval, sizeof(entries)))
 561                         return -EFAULT;
 562
 563                 mutex_lock(&xs->mutex);
 564                 if (!xs->umem) {
 565                         mutex_unlock(&xs->mutex);
 566                         return -EINVAL;
 567                 }
 568
 569                 q = (optname == XDP_UMEM_FILL_RING) ? &xs->umem->fq :
 570                         &xs->umem->cq;
 571                 err = xsk_init_queue(entries, q, true);
 572                 mutex_unlock(&xs->mutex);
 573                 return err;
 574         }
 575         default:
 576                 break;
 577         }
 578
 579         return -ENOPROTOOPT;
 580 }
 581
 582 static int xsk_getsockopt(struct socket *sock, int level, int optname,
 583                           char __user *optval, int __user *optlen)
 584 {
 585         struct sock *sk = sock->sk;
 586         struct xdp_sock *xs = xdp_sk(sk);
 587         int len;
 588
 589         if (level != SOL_XDP)
 590                 return -ENOPROTOOPT;
 591
 592         if (get_user(len, optlen))
 593                 return -EFAULT;
 594         if (len < 0)
 595                 return -EINVAL;
 596
 597         switch (optname) {
 598         case XDP_STATISTICS:
 599         {
 600                 struct xdp_statistics stats;
 601
 602                 if (len < sizeof(stats))
 603                         return -EINVAL;
 604
 605                 mutex_lock(&xs->mutex);
 606                 stats.rx_dropped = xs->rx_dropped;
 607                 stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
 608                 stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
 609                 mutex_unlock(&xs->mutex);
 610
 611                 if (copy_to_user(optval, &stats, sizeof(stats)))
 612                         return -EFAULT;
 613                 if (put_user(sizeof(stats), optlen))
 614                         return -EFAULT;
 615
 616                 return 0;
 617         }
 618         case XDP_MMAP_OFFSETS:
 619         {
 620                 struct xdp_mmap_offsets off;
 621
 622                 if (len < sizeof(off))
 623                         return -EINVAL;
 624
 625                 off.rx.producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
 626                 off.rx.consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
 627                 off.rx.desc     = offsetof(struct xdp_rxtx_ring, desc);
 628                 off.tx.producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
 629                 off.tx.consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
 630                 off.tx.desc     = offsetof(struct xdp_rxtx_ring, desc);
 631
 632                 off.fr.producer = offsetof(struct xdp_umem_ring, ptrs.producer);
 633                 off.fr.consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
 634                 off.fr.desc     = offsetof(struct xdp_umem_ring, desc);
 635                 off.cr.producer = offsetof(struct xdp_umem_ring, ptrs.producer);
 636                 off.cr.consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
 637                 off.cr.desc     = offsetof(struct xdp_umem_ring, desc);
 638
 639                 len = sizeof(off);
 640                 if (copy_to_user(optval, &off, len))
 641                         return -EFAULT;
 642                 if (put_user(len, optlen))
 643                         return -EFAULT;
 644
 645                 return 0;
 646         }
 647         default:
 648                 break;
 649         }
 650
 651         return -EOPNOTSUPP;
 652 }
 653
 654 static int xsk_mmap(struct file *file, struct socket *sock,
 655                     struct vm_area_struct *vma)
 656 {
 657         loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 658         unsigned long size = vma->vm_end - vma->vm_start;
 659         struct xdp_sock *xs = xdp_sk(sock->sk);
 660         struct xsk_queue *q = NULL;
 661         struct xdp_umem *umem;
 662         unsigned long pfn;
 663         struct page *qpg;
 664
 665         if (offset == XDP_PGOFF_RX_RING) {
 666                 q = READ_ONCE(xs->rx);
 667         } else if (offset == XDP_PGOFF_TX_RING) {
 668                 q = READ_ONCE(xs->tx);
 669         } else {
 670                 umem = READ_ONCE(xs->umem);
 671                 if (!umem)
 672                         return -EINVAL;
 673
 674                 /* Matches the smp_wmb() in XDP_UMEM_REG */
 675                 smp_rmb();
 676                 if (offset == XDP_UMEM_PGOFF_FILL_RING)
 677                         q = READ_ONCE(umem->fq);
 678                 else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
 679                         q = READ_ONCE(umem->cq);
 680         }
 681
 682         if (!q)
 683                 return -EINVAL;
 684
 685         /* Matches the smp_wmb() in xsk_init_queue */
 686         smp_rmb();
 687         qpg = virt_to_head_page(q->ring);
 688         if (size > (PAGE_SIZE << compound_order(qpg)))
 689                 return -EINVAL;
 690
 691         pfn = virt_to_phys(q->ring) >> PAGE_SHIFT;
 692         return remap_pfn_range(vma, vma->vm_start, pfn,
 693                                size, vma->vm_page_prot);
 694 }
 695
 696 static struct proto xsk_proto = {
 697         .name =         "XDP",
 698         .owner =        THIS_MODULE,
 699         .obj_size =     sizeof(struct xdp_sock),
 700 };
 701
 702 static const struct proto_ops xsk_proto_ops = {
 703         .family         = PF_XDP,
 704         .owner          = THIS_MODULE,
 705         .release        = xsk_release,
 706         .bind           = xsk_bind,
 707         .connect        = sock_no_connect,
 708         .socketpair     = sock_no_socketpair,
 709         .accept         = sock_no_accept,
 710         .getname        = sock_no_getname,
 711         .poll           = xsk_poll,
 712         .ioctl          = sock_no_ioctl,
 713         .listen         = sock_no_listen,
 714         .shutdown       = sock_no_shutdown,
 715         .setsockopt     = xsk_setsockopt,
 716         .getsockopt     = xsk_getsockopt,
 717         .sendmsg        = xsk_sendmsg,
 718         .recvmsg        = sock_no_recvmsg,
 719         .mmap           = xsk_mmap,
 720         .sendpage       = sock_no_sendpage,
 721 };
 722
 723 static void xsk_destruct(struct sock *sk)
 724 {
 725         struct xdp_sock *xs = xdp_sk(sk);
 726
 727         if (!sock_flag(sk, SOCK_DEAD))
 728                 return;
 729
 730         xdp_put_umem(xs->umem);
 731
 732         sk_refcnt_debug_dec(sk);
 733 }
 734
 735 static int xsk_create(struct net *net, struct socket *sock, int protocol,
 736                       int kern)
 737 {
 738         struct sock *sk;
 739         struct xdp_sock *xs;
 740
 741         if (!ns_capable(net->user_ns, CAP_NET_RAW))
 742                 return -EPERM;
 743         if (sock->type != SOCK_RAW)
 744                 return -ESOCKTNOSUPPORT;
 745
 746         if (protocol)
 747                 return -EPROTONOSUPPORT;
 748
 749         sock->state = SS_UNCONNECTED;
 750
 751         sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern);
 752         if (!sk)
 753                 return -ENOBUFS;
 754
 755         sock->ops = &xsk_proto_ops;
 756
 757         sock_init_data(sock, sk);
 758
 759         sk->sk_family = PF_XDP;
 760
 761         sk->sk_destruct = xsk_destruct;
 762         sk_refcnt_debug_inc(sk);
 763
 764         sock_set_flag(sk, SOCK_RCU_FREE);
 765
 766         xs = xdp_sk(sk);
 767         mutex_init(&xs->mutex);
 768         spin_lock_init(&xs->tx_completion_lock);
 769
 770         mutex_lock(&net->xdp.lock);
 771         sk_add_node_rcu(sk, &net->xdp.list);
 772         mutex_unlock(&net->xdp.lock);
 773
 774         local_bh_disable();
 775         sock_prot_inuse_add(net, &xsk_proto, 1);
 776         local_bh_enable();
 777
 778         return 0;
 779 }
 780
 781 static const struct net_proto_family xsk_family_ops = {
 782         .family = PF_XDP,
 783         .create = xsk_create,
 784         .owner  = THIS_MODULE,
 785 };
 786
 787 static int __net_init xsk_net_init(struct net *net)
 788 {
 789         mutex_init(&net->xdp.lock);
 790         INIT_HLIST_HEAD(&net->xdp.list);
 791         return 0;
 792 }
 793
 794 static void __net_exit xsk_net_exit(struct net *net)
 795 {
 796         WARN_ON_ONCE(!hlist_empty(&net->xdp.list));
 797 }
 798
 799 static struct pernet_operations xsk_net_ops = {
 800         .init = xsk_net_init,
 801         .exit = xsk_net_exit,
 802 };
 803
 804 static int __init xsk_init(void)
 805 {
 806         int err;
 807
 808         err = proto_register(&xsk_proto, 0 /* no slab */);
 809         if (err)
 810                 goto out;
 811
 812         err = sock_register(&xsk_family_ops);
 813         if (err)
 814                 goto out_proto;
 815
 816         err = register_pernet_subsys(&xsk_net_ops);
 817         if (err)
 818                 goto out_sk;
 819         return 0;
 820
 821 out_sk:
 822         sock_unregister(PF_XDP);
 823 out_proto:
 824         proto_unregister(&xsk_proto);
 825 out:
 826         return err;
 827 }
 828
 829 fs_initcall(xsk_init);