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 <linux/vmalloc.h>
  26 #include <net/xdp_sock_drv.h>
  27 #include <net/busy_poll.h>
  28 #include <net/netdev_rx_queue.h>
  29 #include <net/xdp.h>
  30
  31 #include "xsk_queue.h"
  32 #include "xdp_umem.h"
  33 #include "xsk.h"
  34
  35 #define TX_BATCH_SIZE 32
  36 #define MAX_PER_SOCKET_BUDGET (TX_BATCH_SIZE)
  37
  38 static DEFINE_PER_CPU(struct list_head, xskmap_flush_list);
  39
  40 void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool)
  41 {
  42         if (pool->cached_need_wakeup & XDP_WAKEUP_RX)
  43                 return;
  44
  45         pool->fq->ring->flags |= XDP_RING_NEED_WAKEUP;
  46         pool->cached_need_wakeup |= XDP_WAKEUP_RX;
  47 }
  48 EXPORT_SYMBOL(xsk_set_rx_need_wakeup);
  49
  50 void xsk_set_tx_need_wakeup(struct xsk_buff_pool *pool)
  51 {
  52         struct xdp_sock *xs;
  53
  54         if (pool->cached_need_wakeup & XDP_WAKEUP_TX)
  55                 return;
  56
  57         rcu_read_lock();
  58         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
  59                 xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
  60         }
  61         rcu_read_unlock();
  62
  63         pool->cached_need_wakeup |= XDP_WAKEUP_TX;
  64 }
  65 EXPORT_SYMBOL(xsk_set_tx_need_wakeup);
  66
  67 void xsk_clear_rx_need_wakeup(struct xsk_buff_pool *pool)
  68 {
  69         if (!(pool->cached_need_wakeup & XDP_WAKEUP_RX))
  70                 return;
  71
  72         pool->fq->ring->flags &= ~XDP_RING_NEED_WAKEUP;
  73         pool->cached_need_wakeup &= ~XDP_WAKEUP_RX;
  74 }
  75 EXPORT_SYMBOL(xsk_clear_rx_need_wakeup);
  76
  77 void xsk_clear_tx_need_wakeup(struct xsk_buff_pool *pool)
  78 {
  79         struct xdp_sock *xs;
  80
  81         if (!(pool->cached_need_wakeup & XDP_WAKEUP_TX))
  82                 return;
  83
  84         rcu_read_lock();
  85         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
  86                 xs->tx->ring->flags &= ~XDP_RING_NEED_WAKEUP;
  87         }
  88         rcu_read_unlock();
  89
  90         pool->cached_need_wakeup &= ~XDP_WAKEUP_TX;
  91 }
  92 EXPORT_SYMBOL(xsk_clear_tx_need_wakeup);
  93
  94 bool xsk_uses_need_wakeup(struct xsk_buff_pool *pool)
  95 {
  96         return pool->uses_need_wakeup;
  97 }
  98 EXPORT_SYMBOL(xsk_uses_need_wakeup);
  99
 100 struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev,
 101                                             u16 queue_id)
 102 {
 103         if (queue_id < dev->real_num_rx_queues)
 104                 return dev->_rx[queue_id].pool;
 105         if (queue_id < dev->real_num_tx_queues)
 106                 return dev->_tx[queue_id].pool;
 107
 108         return NULL;
 109 }
 110 EXPORT_SYMBOL(xsk_get_pool_from_qid);
 111
 112 void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
 113 {
 114         if (queue_id < dev->num_rx_queues)
 115                 dev->_rx[queue_id].pool = NULL;
 116         if (queue_id < dev->num_tx_queues)
 117                 dev->_tx[queue_id].pool = NULL;
 118 }
 119
 120 /* The buffer pool is stored both in the _rx struct and the _tx struct as we do
 121  * not know if the device has more tx queues than rx, or the opposite.
 122  * This might also change during run time.
 123  */
 124 int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
 125                         u16 queue_id)
 126 {
 127         if (queue_id >= max_t(unsigned int,
 128                               dev->real_num_rx_queues,
 129                               dev->real_num_tx_queues))
 130                 return -EINVAL;
 131
 132         if (queue_id < dev->real_num_rx_queues)
 133                 dev->_rx[queue_id].pool = pool;
 134         if (queue_id < dev->real_num_tx_queues)
 135                 dev->_tx[queue_id].pool = pool;
 136
 137         return 0;
 138 }
 139
 140 static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff_xsk *xskb, u32 len,
 141                         u32 flags)
 142 {
 143         u64 addr;
 144         int err;
 145
 146         addr = xp_get_handle(xskb);
 147         err = xskq_prod_reserve_desc(xs->rx, addr, len, flags);
 148         if (err) {
 149                 xs->rx_queue_full++;
 150                 return err;
 151         }
 152
 153         xp_release(xskb);
 154         return 0;
 155 }
 156
 157 static int xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
 158 {
 159         struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
 160         u32 frags = xdp_buff_has_frags(xdp);
 161         struct xdp_buff_xsk *pos, *tmp;
 162         struct list_head *xskb_list;
 163         u32 contd = 0;
 164         int err;
 165
 166         if (frags)
 167                 contd = XDP_PKT_CONTD;
 168
 169         err = __xsk_rcv_zc(xs, xskb, len, contd);
 170         if (err)
 171                 goto err;
 172         if (likely(!frags))
 173                 return 0;
 174
 175         xskb_list = &xskb->pool->xskb_list;
 176         list_for_each_entry_safe(pos, tmp, xskb_list, xskb_list_node) {
 177                 if (list_is_singular(xskb_list))
 178                         contd = 0;
 179                 len = pos->xdp.data_end - pos->xdp.data;
 180                 err = __xsk_rcv_zc(xs, pos, len, contd);
 181                 if (err)
 182                         goto err;
 183                 list_del(&pos->xskb_list_node);
 184         }
 185
 186         return 0;
 187 err:
 188         xsk_buff_free(xdp);
 189         return err;
 190 }
 191
 192 static void *xsk_copy_xdp_start(struct xdp_buff *from)
 193 {
 194         if (unlikely(xdp_data_meta_unsupported(from)))
 195                 return from->data;
 196         else
 197                 return from->data_meta;
 198 }
 199
 200 static u32 xsk_copy_xdp(void *to, void **from, u32 to_len,
 201                         u32 *from_len, skb_frag_t **frag, u32 rem)
 202 {
 203         u32 copied = 0;
 204
 205         while (1) {
 206                 u32 copy_len = min_t(u32, *from_len, to_len);
 207
 208                 memcpy(to, *from, copy_len);
 209                 copied += copy_len;
 210                 if (rem == copied)
 211                         return copied;
 212
 213                 if (*from_len == copy_len) {
 214                         *from = skb_frag_address(*frag);
 215                         *from_len = skb_frag_size((*frag)++);
 216                 } else {
 217                         *from += copy_len;
 218                         *from_len -= copy_len;
 219                 }
 220                 if (to_len == copy_len)
 221                         return copied;
 222
 223                 to_len -= copy_len;
 224                 to += copy_len;
 225         }
 226 }
 227
 228 static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
 229 {
 230         u32 frame_size = xsk_pool_get_rx_frame_size(xs->pool);
 231         void *copy_from = xsk_copy_xdp_start(xdp), *copy_to;
 232         u32 from_len, meta_len, rem, num_desc;
 233         struct xdp_buff_xsk *xskb;
 234         struct xdp_buff *xsk_xdp;
 235         skb_frag_t *frag;
 236
 237         from_len = xdp->data_end - copy_from;
 238         meta_len = xdp->data - copy_from;
 239         rem = len + meta_len;
 240
 241         if (len <= frame_size && !xdp_buff_has_frags(xdp)) {
 242                 int err;
 243
 244                 xsk_xdp = xsk_buff_alloc(xs->pool);
 245                 if (!xsk_xdp) {
 246                         xs->rx_dropped++;
 247                         return -ENOMEM;
 248                 }
 249                 memcpy(xsk_xdp->data - meta_len, copy_from, rem);
 250                 xskb = container_of(xsk_xdp, struct xdp_buff_xsk, xdp);
 251                 err = __xsk_rcv_zc(xs, xskb, len, 0);
 252                 if (err) {
 253                         xsk_buff_free(xsk_xdp);
 254                         return err;
 255                 }
 256
 257                 return 0;
 258         }
 259
 260         num_desc = (len - 1) / frame_size + 1;
 261
 262         if (!xsk_buff_can_alloc(xs->pool, num_desc)) {
 263                 xs->rx_dropped++;
 264                 return -ENOMEM;
 265         }
 266         if (xskq_prod_nb_free(xs->rx, num_desc) < num_desc) {
 267                 xs->rx_queue_full++;
 268                 return -ENOBUFS;
 269         }
 270
 271         if (xdp_buff_has_frags(xdp)) {
 272                 struct skb_shared_info *sinfo;
 273
 274                 sinfo = xdp_get_shared_info_from_buff(xdp);
 275                 frag =  &sinfo->frags[0];
 276         }
 277
 278         do {
 279                 u32 to_len = frame_size + meta_len;
 280                 u32 copied;
 281
 282                 xsk_xdp = xsk_buff_alloc(xs->pool);
 283                 copy_to = xsk_xdp->data - meta_len;
 284
 285                 copied = xsk_copy_xdp(copy_to, &copy_from, to_len, &from_len, &frag, rem);
 286                 rem -= copied;
 287
 288                 xskb = container_of(xsk_xdp, struct xdp_buff_xsk, xdp);
 289                 __xsk_rcv_zc(xs, xskb, copied - meta_len, rem ? XDP_PKT_CONTD : 0);
 290                 meta_len = 0;
 291         } while (rem);
 292
 293         return 0;
 294 }
 295
 296 static bool xsk_tx_writeable(struct xdp_sock *xs)
 297 {
 298         if (xskq_cons_present_entries(xs->tx) > xs->tx->nentries / 2)
 299                 return false;
 300
 301         return true;
 302 }
 303
 304 static bool xsk_is_bound(struct xdp_sock *xs)
 305 {
 306         if (READ_ONCE(xs->state) == XSK_BOUND) {
 307                 /* Matches smp_wmb() in bind(). */
 308                 smp_rmb();
 309                 return true;
 310         }
 311         return false;
 312 }
 313
 314 static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
 315 {
 316         if (!xsk_is_bound(xs))
 317                 return -ENXIO;
 318
 319         if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
 320                 return -EINVAL;
 321
 322         if (len > xsk_pool_get_rx_frame_size(xs->pool) && !xs->sg) {
 323                 xs->rx_dropped++;
 324                 return -ENOSPC;
 325         }
 326
 327         sk_mark_napi_id_once_xdp(&xs->sk, xdp);
 328         return 0;
 329 }
 330
 331 static void xsk_flush(struct xdp_sock *xs)
 332 {
 333         xskq_prod_submit(xs->rx);
 334         __xskq_cons_release(xs->pool->fq);
 335         sock_def_readable(&xs->sk);
 336 }
 337
 338 int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 339 {
 340         u32 len = xdp_get_buff_len(xdp);
 341         int err;
 342
 343         spin_lock_bh(&xs->rx_lock);
 344         err = xsk_rcv_check(xs, xdp, len);
 345         if (!err) {
 346                 err = __xsk_rcv(xs, xdp, len);
 347                 xsk_flush(xs);
 348         }
 349         spin_unlock_bh(&xs->rx_lock);
 350         return err;
 351 }
 352
 353 static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 354 {
 355         u32 len = xdp_get_buff_len(xdp);
 356         int err;
 357
 358         err = xsk_rcv_check(xs, xdp, len);
 359         if (err)
 360                 return err;
 361
 362         if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) {
 363                 len = xdp->data_end - xdp->data;
 364                 return xsk_rcv_zc(xs, xdp, len);
 365         }
 366
 367         err = __xsk_rcv(xs, xdp, len);
 368         if (!err)
 369                 xdp_return_buff(xdp);
 370         return err;
 371 }
 372
 373 int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
 374 {
 375         struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
 376         int err;
 377
 378         err = xsk_rcv(xs, xdp);
 379         if (err)
 380                 return err;
 381
 382         if (!xs->flush_node.prev)
 383                 list_add(&xs->flush_node, flush_list);
 384
 385         return 0;
 386 }
 387
 388 void __xsk_map_flush(void)
 389 {
 390         struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
 391         struct xdp_sock *xs, *tmp;
 392
 393         list_for_each_entry_safe(xs, tmp, flush_list, flush_node) {
 394                 xsk_flush(xs);
 395                 __list_del_clearprev(&xs->flush_node);
 396         }
 397 }
 398
 399 #ifdef CONFIG_DEBUG_NET
 400 bool xsk_map_check_flush(void)
 401 {
 402         if (list_empty(this_cpu_ptr(&xskmap_flush_list)))
 403                 return false;
 404         __xsk_map_flush();
 405         return true;
 406 }
 407 #endif
 408
 409 void xsk_tx_completed(struct xsk_buff_pool *pool, u32 nb_entries)
 410 {
 411         xskq_prod_submit_n(pool->cq, nb_entries);
 412 }
 413 EXPORT_SYMBOL(xsk_tx_completed);
 414
 415 void xsk_tx_release(struct xsk_buff_pool *pool)
 416 {
 417         struct xdp_sock *xs;
 418
 419         rcu_read_lock();
 420         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
 421                 __xskq_cons_release(xs->tx);
 422                 if (xsk_tx_writeable(xs))
 423                         xs->sk.sk_write_space(&xs->sk);
 424         }
 425         rcu_read_unlock();
 426 }
 427 EXPORT_SYMBOL(xsk_tx_release);
 428
 429 bool xsk_tx_peek_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc)
 430 {
 431         bool budget_exhausted = false;
 432         struct xdp_sock *xs;
 433
 434         rcu_read_lock();
 435 again:
 436         list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
 437                 if (xs->tx_budget_spent >= MAX_PER_SOCKET_BUDGET) {
 438                         budget_exhausted = true;
 439                         continue;
 440                 }
 441
 442                 if (!xskq_cons_peek_desc(xs->tx, desc, pool)) {
 443                         if (xskq_has_descs(xs->tx))
 444                                 xskq_cons_release(xs->tx);
 445                         continue;
 446                 }
 447
 448                 xs->tx_budget_spent++;
 449
 450                 /* This is the backpressure mechanism for the Tx path.
 451                  * Reserve space in the completion queue and only proceed
 452                  * if there is space in it. This avoids having to implement
 453                  * any buffering in the Tx path.
 454                  */
 455                 if (xskq_prod_reserve_addr(pool->cq, desc->addr))
 456                         goto out;
 457
 458                 xskq_cons_release(xs->tx);
 459                 rcu_read_unlock();
 460                 return true;
 461         }
 462
 463         if (budget_exhausted) {
 464                 list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list)
 465                         xs->tx_budget_spent = 0;
 466
 467                 budget_exhausted = false;
 468                 goto again;
 469         }
 470
 471 out:
 472         rcu_read_unlock();
 473         return false;
 474 }
 475 EXPORT_SYMBOL(xsk_tx_peek_desc);
 476
 477 static u32 xsk_tx_peek_release_fallback(struct xsk_buff_pool *pool, u32 max_entries)
 478 {
 479         struct xdp_desc *descs = pool->tx_descs;
 480         u32 nb_pkts = 0;
 481
 482         while (nb_pkts < max_entries && xsk_tx_peek_desc(pool, &descs[nb_pkts]))
 483                 nb_pkts++;
 484
 485         xsk_tx_release(pool);
 486         return nb_pkts;
 487 }
 488
 489 u32 xsk_tx_peek_release_desc_batch(struct xsk_buff_pool *pool, u32 nb_pkts)
 490 {
 491         struct xdp_sock *xs;
 492
 493         rcu_read_lock();
 494         if (!list_is_singular(&pool->xsk_tx_list)) {
 495                 /* Fallback to the non-batched version */
 496                 rcu_read_unlock();
 497                 return xsk_tx_peek_release_fallback(pool, nb_pkts);
 498         }
 499
 500         xs = list_first_or_null_rcu(&pool->xsk_tx_list, struct xdp_sock, tx_list);
 501         if (!xs) {
 502                 nb_pkts = 0;
 503                 goto out;
 504         }
 505
 506         nb_pkts = xskq_cons_nb_entries(xs->tx, nb_pkts);
 507
 508         /* This is the backpressure mechanism for the Tx path. Try to
 509          * reserve space in the completion queue for all packets, but
 510          * if there are fewer slots available, just process that many
 511          * packets. This avoids having to implement any buffering in
 512          * the Tx path.
 513          */
 514         nb_pkts = xskq_prod_nb_free(pool->cq, nb_pkts);
 515         if (!nb_pkts)
 516                 goto out;
 517
 518         nb_pkts = xskq_cons_read_desc_batch(xs->tx, pool, nb_pkts);
 519         if (!nb_pkts) {
 520                 xs->tx->queue_empty_descs++;
 521                 goto out;
 522         }
 523
 524         __xskq_cons_release(xs->tx);
 525         xskq_prod_write_addr_batch(pool->cq, pool->tx_descs, nb_pkts);
 526         xs->sk.sk_write_space(&xs->sk);
 527
 528 out:
 529         rcu_read_unlock();
 530         return nb_pkts;
 531 }
 532 EXPORT_SYMBOL(xsk_tx_peek_release_desc_batch);
 533
 534 static int xsk_wakeup(struct xdp_sock *xs, u8 flags)
 535 {
 536         struct net_device *dev = xs->dev;
 537
 538         return dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, flags);
 539 }
 540
 541 static int xsk_cq_reserve_addr_locked(struct xdp_sock *xs, u64 addr)
 542 {
 543         unsigned long flags;
 544         int ret;
 545
 546         spin_lock_irqsave(&xs->pool->cq_lock, flags);
 547         ret = xskq_prod_reserve_addr(xs->pool->cq, addr);
 548         spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
 549
 550         return ret;
 551 }
 552
 553 static void xsk_cq_submit_locked(struct xdp_sock *xs, u32 n)
 554 {
 555         unsigned long flags;
 556
 557         spin_lock_irqsave(&xs->pool->cq_lock, flags);
 558         xskq_prod_submit_n(xs->pool->cq, n);
 559         spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
 560 }
 561
 562 static void xsk_cq_cancel_locked(struct xdp_sock *xs, u32 n)
 563 {
 564         unsigned long flags;
 565
 566         spin_lock_irqsave(&xs->pool->cq_lock, flags);
 567         xskq_prod_cancel_n(xs->pool->cq, n);
 568         spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
 569 }
 570
 571 static u32 xsk_get_num_desc(struct sk_buff *skb)
 572 {
 573         return skb ? (long)skb_shinfo(skb)->destructor_arg : 0;
 574 }
 575
 576 static void xsk_destruct_skb(struct sk_buff *skb)
 577 {
 578         struct xsk_tx_metadata_compl *compl = &skb_shinfo(skb)->xsk_meta;
 579
 580         if (compl->tx_timestamp) {
 581                 /* sw completion timestamp, not a real one */
 582                 *compl->tx_timestamp = ktime_get_tai_fast_ns();
 583         }
 584
 585         xsk_cq_submit_locked(xdp_sk(skb->sk), xsk_get_num_desc(skb));
 586         sock_wfree(skb);
 587 }
 588
 589 static void xsk_set_destructor_arg(struct sk_buff *skb)
 590 {
 591         long num = xsk_get_num_desc(xdp_sk(skb->sk)->skb) + 1;
 592
 593         skb_shinfo(skb)->destructor_arg = (void *)num;
 594 }
 595
 596 static void xsk_consume_skb(struct sk_buff *skb)
 597 {
 598         struct xdp_sock *xs = xdp_sk(skb->sk);
 599
 600         skb->destructor = sock_wfree;
 601         xsk_cq_cancel_locked(xs, xsk_get_num_desc(skb));
 602         /* Free skb without triggering the perf drop trace */
 603         consume_skb(skb);
 604         xs->skb = NULL;
 605 }
 606
 607 static void xsk_drop_skb(struct sk_buff *skb)
 608 {
 609         xdp_sk(skb->sk)->tx->invalid_descs += xsk_get_num_desc(skb);
 610         xsk_consume_skb(skb);
 611 }
 612
 613 static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs,
 614                                               struct xdp_desc *desc)
 615 {
 616         struct xsk_buff_pool *pool = xs->pool;
 617         u32 hr, len, ts, offset, copy, copied;
 618         struct sk_buff *skb = xs->skb;
 619         struct page *page;
 620         void *buffer;
 621         int err, i;
 622         u64 addr;
 623
 624         if (!skb) {
 625                 hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(xs->dev->needed_headroom));
 626
 627                 skb = sock_alloc_send_skb(&xs->sk, hr, 1, &err);
 628                 if (unlikely(!skb))
 629                         return ERR_PTR(err);
 630
 631                 skb_reserve(skb, hr);
 632         }
 633
 634         addr = desc->addr;
 635         len = desc->len;
 636         ts = pool->unaligned ? len : pool->chunk_size;
 637
 638         buffer = xsk_buff_raw_get_data(pool, addr);
 639         offset = offset_in_page(buffer);
 640         addr = buffer - pool->addrs;
 641
 642         for (copied = 0, i = skb_shinfo(skb)->nr_frags; copied < len; i++) {
 643                 if (unlikely(i >= MAX_SKB_FRAGS))
 644                         return ERR_PTR(-EOVERFLOW);
 645
 646                 page = pool->umem->pgs[addr >> PAGE_SHIFT];
 647                 get_page(page);
 648
 649                 copy = min_t(u32, PAGE_SIZE - offset, len - copied);
 650                 skb_fill_page_desc(skb, i, page, offset, copy);
 651
 652                 copied += copy;
 653                 addr += copy;
 654                 offset = 0;
 655         }
 656
 657         skb->len += len;
 658         skb->data_len += len;
 659         skb->truesize += ts;
 660
 661         refcount_add(ts, &xs->sk.sk_wmem_alloc);
 662
 663         return skb;
 664 }
 665
 666 static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 667                                      struct xdp_desc *desc)
 668 {
 669         struct xsk_tx_metadata *meta = NULL;
 670         struct net_device *dev = xs->dev;
 671         struct sk_buff *skb = xs->skb;
 672         bool first_frag = false;
 673         int err;
 674
 675         if (dev->priv_flags & IFF_TX_SKB_NO_LINEAR) {
 676                 skb = xsk_build_skb_zerocopy(xs, desc);
 677                 if (IS_ERR(skb)) {
 678                         err = PTR_ERR(skb);
 679                         goto free_err;
 680                 }
 681         } else {
 682                 u32 hr, tr, len;
 683                 void *buffer;
 684
 685                 buffer = xsk_buff_raw_get_data(xs->pool, desc->addr);
 686                 len = desc->len;
 687
 688                 if (!skb) {
 689                         hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(dev->needed_headroom));
 690                         tr = dev->needed_tailroom;
 691                         skb = sock_alloc_send_skb(&xs->sk, hr + len + tr, 1, &err);
 692                         if (unlikely(!skb))
 693                                 goto free_err;
 694
 695                         skb_reserve(skb, hr);
 696                         skb_put(skb, len);
 697
 698                         err = skb_store_bits(skb, 0, buffer, len);
 699                         if (unlikely(err)) {
 700                                 kfree_skb(skb);
 701                                 goto free_err;
 702                         }
 703
 704                         first_frag = true;
 705                 } else {
 706                         int nr_frags = skb_shinfo(skb)->nr_frags;
 707                         struct page *page;
 708                         u8 *vaddr;
 709
 710                         if (unlikely(nr_frags == (MAX_SKB_FRAGS - 1) && xp_mb_desc(desc))) {
 711                                 err = -EOVERFLOW;
 712                                 goto free_err;
 713                         }
 714
 715                         page = alloc_page(xs->sk.sk_allocation);
 716                         if (unlikely(!page)) {
 717                                 err = -EAGAIN;
 718                                 goto free_err;
 719                         }
 720
 721                         vaddr = kmap_local_page(page);
 722                         memcpy(vaddr, buffer, len);
 723                         kunmap_local(vaddr);
 724
 725                         skb_add_rx_frag(skb, nr_frags, page, 0, len, PAGE_SIZE);
 726                         refcount_add(PAGE_SIZE, &xs->sk.sk_wmem_alloc);
 727                 }
 728
 729                 if (first_frag && desc->options & XDP_TX_METADATA) {
 730                         if (unlikely(xs->pool->tx_metadata_len == 0)) {
 731                                 err = -EINVAL;
 732                                 goto free_err;
 733                         }
 734
 735                         meta = buffer - xs->pool->tx_metadata_len;
 736                         if (unlikely(!xsk_buff_valid_tx_metadata(meta))) {
 737                                 err = -EINVAL;
 738                                 goto free_err;
 739                         }
 740
 741                         if (meta->flags & XDP_TXMD_FLAGS_CHECKSUM) {
 742                                 if (unlikely(meta->request.csum_start +
 743                                              meta->request.csum_offset +
 744                                              sizeof(__sum16) > len)) {
 745                                         err = -EINVAL;
 746                                         goto free_err;
 747                                 }
 748
 749                                 skb->csum_start = hr + meta->request.csum_start;
 750                                 skb->csum_offset = meta->request.csum_offset;
 751                                 skb->ip_summed = CHECKSUM_PARTIAL;
 752
 753                                 if (unlikely(xs->pool->tx_sw_csum)) {
 754                                         err = skb_checksum_help(skb);
 755                                         if (err)
 756                                                 goto free_err;
 757                                 }
 758                         }
 759                 }
 760         }
 761
 762         skb->dev = dev;
 763         skb->priority = READ_ONCE(xs->sk.sk_priority);
 764         skb->mark = READ_ONCE(xs->sk.sk_mark);
 765         skb->destructor = xsk_destruct_skb;
 766         xsk_tx_metadata_to_compl(meta, &skb_shinfo(skb)->xsk_meta);
 767         xsk_set_destructor_arg(skb);
 768
 769         return skb;
 770
 771 free_err:
 772         if (err == -EOVERFLOW) {
 773                 /* Drop the packet */
 774                 xsk_set_destructor_arg(xs->skb);
 775                 xsk_drop_skb(xs->skb);
 776                 xskq_cons_release(xs->tx);
 777         } else {
 778                 /* Let application retry */
 779                 xsk_cq_cancel_locked(xs, 1);
 780         }
 781
 782         return ERR_PTR(err);
 783 }
 784
 785 static int __xsk_generic_xmit(struct sock *sk)
 786 {
 787         struct xdp_sock *xs = xdp_sk(sk);
 788         u32 max_batch = TX_BATCH_SIZE;
 789         bool sent_frame = false;
 790         struct xdp_desc desc;
 791         struct sk_buff *skb;
 792         int err = 0;
 793
 794         mutex_lock(&xs->mutex);
 795
 796         /* Since we dropped the RCU read lock, the socket state might have changed. */
 797         if (unlikely(!xsk_is_bound(xs))) {
 798                 err = -ENXIO;
 799                 goto out;
 800         }
 801
 802         if (xs->queue_id >= xs->dev->real_num_tx_queues)
 803                 goto out;
 804
 805         while (xskq_cons_peek_desc(xs->tx, &desc, xs->pool)) {
 806                 if (max_batch-- == 0) {
 807                         err = -EAGAIN;
 808                         goto out;
 809                 }
 810
 811                 /* This is the backpressure mechanism for the Tx path.
 812                  * Reserve space in the completion queue and only proceed
 813                  * if there is space in it. This avoids having to implement
 814                  * any buffering in the Tx path.
 815                  */
 816                 if (xsk_cq_reserve_addr_locked(xs, desc.addr))
 817                         goto out;
 818
 819                 skb = xsk_build_skb(xs, &desc);
 820                 if (IS_ERR(skb)) {
 821                         err = PTR_ERR(skb);
 822                         if (err != -EOVERFLOW)
 823                                 goto out;
 824                         err = 0;
 825                         continue;
 826                 }
 827
 828                 xskq_cons_release(xs->tx);
 829
 830                 if (xp_mb_desc(&desc)) {
 831                         xs->skb = skb;
 832                         continue;
 833                 }
 834
 835                 err = __dev_direct_xmit(skb, xs->queue_id);
 836                 if  (err == NETDEV_TX_BUSY) {
 837                         /* Tell user-space to retry the send */
 838                         xskq_cons_cancel_n(xs->tx, xsk_get_num_desc(skb));
 839                         xsk_consume_skb(skb);
 840                         err = -EAGAIN;
 841                         goto out;
 842                 }
 843
 844                 /* Ignore NET_XMIT_CN as packet might have been sent */
 845                 if (err == NET_XMIT_DROP) {
 846                         /* SKB completed but not sent */
 847                         err = -EBUSY;
 848                         xs->skb = NULL;
 849                         goto out;
 850                 }
 851
 852                 sent_frame = true;
 853                 xs->skb = NULL;
 854         }
 855
 856         if (xskq_has_descs(xs->tx)) {
 857                 if (xs->skb)
 858                         xsk_drop_skb(xs->skb);
 859                 xskq_cons_release(xs->tx);
 860         }
 861
 862 out:
 863         if (sent_frame)
 864                 if (xsk_tx_writeable(xs))
 865                         sk->sk_write_space(sk);
 866
 867         mutex_unlock(&xs->mutex);
 868         return err;
 869 }
 870
 871 static int xsk_generic_xmit(struct sock *sk)
 872 {
 873         int ret;
 874
 875         /* Drop the RCU lock since the SKB path might sleep. */
 876         rcu_read_unlock();
 877         ret = __xsk_generic_xmit(sk);
 878         /* Reaquire RCU lock before going into common code. */
 879         rcu_read_lock();
 880
 881         return ret;
 882 }
 883
 884 static bool xsk_no_wakeup(struct sock *sk)
 885 {
 886 #ifdef CONFIG_NET_RX_BUSY_POLL
 887         /* Prefer busy-polling, skip the wakeup. */
 888         return READ_ONCE(sk->sk_prefer_busy_poll) && READ_ONCE(sk->sk_ll_usec) &&
 889                 READ_ONCE(sk->sk_napi_id) >= MIN_NAPI_ID;
 890 #else
 891         return false;
 892 #endif
 893 }
 894
 895 static int xsk_check_common(struct xdp_sock *xs)
 896 {
 897         if (unlikely(!xsk_is_bound(xs)))
 898                 return -ENXIO;
 899         if (unlikely(!(xs->dev->flags & IFF_UP)))
 900                 return -ENETDOWN;
 901
 902         return 0;
 903 }
 904
 905 static int __xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 906 {
 907         bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
 908         struct sock *sk = sock->sk;
 909         struct xdp_sock *xs = xdp_sk(sk);
 910         struct xsk_buff_pool *pool;
 911         int err;
 912
 913         err = xsk_check_common(xs);
 914         if (err)
 915                 return err;
 916         if (unlikely(need_wait))
 917                 return -EOPNOTSUPP;
 918         if (unlikely(!xs->tx))
 919                 return -ENOBUFS;
 920
 921         if (sk_can_busy_loop(sk)) {
 922                 if (xs->zc)
 923                         __sk_mark_napi_id_once(sk, xsk_pool_get_napi_id(xs->pool));
 924                 sk_busy_loop(sk, 1); /* only support non-blocking sockets */
 925         }
 926
 927         if (xs->zc && xsk_no_wakeup(sk))
 928                 return 0;
 929
 930         pool = xs->pool;
 931         if (pool->cached_need_wakeup & XDP_WAKEUP_TX) {
 932                 if (xs->zc)
 933                         return xsk_wakeup(xs, XDP_WAKEUP_TX);
 934                 return xsk_generic_xmit(sk);
 935         }
 936         return 0;
 937 }
 938
 939 static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 940 {
 941         int ret;
 942
 943         rcu_read_lock();
 944         ret = __xsk_sendmsg(sock, m, total_len);
 945         rcu_read_unlock();
 946
 947         return ret;
 948 }
 949
 950 static int __xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
 951 {
 952         bool need_wait = !(flags & MSG_DONTWAIT);
 953         struct sock *sk = sock->sk;
 954         struct xdp_sock *xs = xdp_sk(sk);
 955         int err;
 956
 957         err = xsk_check_common(xs);
 958         if (err)
 959                 return err;
 960         if (unlikely(!xs->rx))
 961                 return -ENOBUFS;
 962         if (unlikely(need_wait))
 963                 return -EOPNOTSUPP;
 964
 965         if (sk_can_busy_loop(sk))
 966                 sk_busy_loop(sk, 1); /* only support non-blocking sockets */
 967
 968         if (xsk_no_wakeup(sk))
 969                 return 0;
 970
 971         if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc)
 972                 return xsk_wakeup(xs, XDP_WAKEUP_RX);
 973         return 0;
 974 }
 975
 976 static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
 977 {
 978         int ret;
 979
 980         rcu_read_lock();
 981         ret = __xsk_recvmsg(sock, m, len, flags);
 982         rcu_read_unlock();
 983
 984         return ret;
 985 }
 986
 987 static __poll_t xsk_poll(struct file *file, struct socket *sock,
 988                              struct poll_table_struct *wait)
 989 {
 990         __poll_t mask = 0;
 991         struct sock *sk = sock->sk;
 992         struct xdp_sock *xs = xdp_sk(sk);
 993         struct xsk_buff_pool *pool;
 994
 995         sock_poll_wait(file, sock, wait);
 996
 997         rcu_read_lock();
 998         if (xsk_check_common(xs))
 999                 goto out;
1000
1001         pool = xs->pool;
1002
1003         if (pool->cached_need_wakeup) {
1004                 if (xs->zc)
1005                         xsk_wakeup(xs, pool->cached_need_wakeup);
1006                 else if (xs->tx)
1007                         /* Poll needs to drive Tx also in copy mode */
1008                         xsk_generic_xmit(sk);
1009         }
1010
1011         if (xs->rx && !xskq_prod_is_empty(xs->rx))
1012                 mask |= EPOLLIN | EPOLLRDNORM;
1013         if (xs->tx && xsk_tx_writeable(xs))
1014                 mask |= EPOLLOUT | EPOLLWRNORM;
1015 out:
1016         rcu_read_unlock();
1017         return mask;
1018 }
1019
1020 static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
1021                           bool umem_queue)
1022 {
1023         struct xsk_queue *q;
1024
1025         if (entries == 0 || *queue || !is_power_of_2(entries))
1026                 return -EINVAL;
1027
1028         q = xskq_create(entries, umem_queue);
1029         if (!q)
1030                 return -ENOMEM;
1031
1032         /* Make sure queue is ready before it can be seen by others */
1033         smp_wmb();
1034         WRITE_ONCE(*queue, q);
1035         return 0;
1036 }
1037
1038 static void xsk_unbind_dev(struct xdp_sock *xs)
1039 {
1040         struct net_device *dev = xs->dev;
1041
1042         if (xs->state != XSK_BOUND)
1043                 return;
1044         WRITE_ONCE(xs->state, XSK_UNBOUND);
1045
1046         /* Wait for driver to stop using the xdp socket. */
1047         xp_del_xsk(xs->pool, xs);
1048         synchronize_net();
1049         dev_put(dev);
1050 }
1051
1052 static struct xsk_map *xsk_get_map_list_entry(struct xdp_sock *xs,
1053                                               struct xdp_sock __rcu ***map_entry)
1054 {
1055         struct xsk_map *map = NULL;
1056         struct xsk_map_node *node;
1057
1058         *map_entry = NULL;
1059
1060         spin_lock_bh(&xs->map_list_lock);
1061         node = list_first_entry_or_null(&xs->map_list, struct xsk_map_node,
1062                                         node);
1063         if (node) {
1064                 bpf_map_inc(&node->map->map);
1065                 map = node->map;
1066                 *map_entry = node->map_entry;
1067         }
1068         spin_unlock_bh(&xs->map_list_lock);
1069         return map;
1070 }
1071
1072 static void xsk_delete_from_maps(struct xdp_sock *xs)
1073 {
1074         /* This function removes the current XDP socket from all the
1075          * maps it resides in. We need to take extra care here, due to
1076          * the two locks involved. Each map has a lock synchronizing
1077          * updates to the entries, and each socket has a lock that
1078          * synchronizes access to the list of maps (map_list). For
1079          * deadlock avoidance the locks need to be taken in the order
1080          * "map lock"->"socket map list lock". We start off by
1081          * accessing the socket map list, and take a reference to the
1082          * map to guarantee existence between the
1083          * xsk_get_map_list_entry() and xsk_map_try_sock_delete()
1084          * calls. Then we ask the map to remove the socket, which
1085          * tries to remove the socket from the map. Note that there
1086          * might be updates to the map between
1087          * xsk_get_map_list_entry() and xsk_map_try_sock_delete().
1088          */
1089         struct xdp_sock __rcu **map_entry = NULL;
1090         struct xsk_map *map;
1091
1092         while ((map = xsk_get_map_list_entry(xs, &map_entry))) {
1093                 xsk_map_try_sock_delete(map, xs, map_entry);
1094                 bpf_map_put(&map->map);
1095         }
1096 }
1097
1098 static int xsk_release(struct socket *sock)
1099 {
1100         struct sock *sk = sock->sk;
1101         struct xdp_sock *xs = xdp_sk(sk);
1102         struct net *net;
1103
1104         if (!sk)
1105                 return 0;
1106
1107         net = sock_net(sk);
1108
1109         if (xs->skb)
1110                 xsk_drop_skb(xs->skb);
1111
1112         mutex_lock(&net->xdp.lock);
1113         sk_del_node_init_rcu(sk);
1114         mutex_unlock(&net->xdp.lock);
1115
1116         sock_prot_inuse_add(net, sk->sk_prot, -1);
1117
1118         xsk_delete_from_maps(xs);
1119         mutex_lock(&xs->mutex);
1120         xsk_unbind_dev(xs);
1121         mutex_unlock(&xs->mutex);
1122
1123         xskq_destroy(xs->rx);
1124         xskq_destroy(xs->tx);
1125         xskq_destroy(xs->fq_tmp);
1126         xskq_destroy(xs->cq_tmp);
1127
1128         sock_orphan(sk);
1129         sock->sk = NULL;
1130
1131         sock_put(sk);
1132
1133         return 0;
1134 }
1135
1136 static struct socket *xsk_lookup_xsk_from_fd(int fd)
1137 {
1138         struct socket *sock;
1139         int err;
1140
1141         sock = sockfd_lookup(fd, &err);
1142         if (!sock)
1143                 return ERR_PTR(-ENOTSOCK);
1144
1145         if (sock->sk->sk_family != PF_XDP) {
1146                 sockfd_put(sock);
1147                 return ERR_PTR(-ENOPROTOOPT);
1148         }
1149
1150         return sock;
1151 }
1152
1153 static bool xsk_validate_queues(struct xdp_sock *xs)
1154 {
1155         return xs->fq_tmp && xs->cq_tmp;
1156 }
1157
1158 static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
1159 {
1160         struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr;
1161         struct sock *sk = sock->sk;
1162         struct xdp_sock *xs = xdp_sk(sk);
1163         struct net_device *dev;
1164         int bound_dev_if;
1165         u32 flags, qid;
1166         int err = 0;
1167
1168         if (addr_len < sizeof(struct sockaddr_xdp))
1169                 return -EINVAL;
1170         if (sxdp->sxdp_family != AF_XDP)
1171                 return -EINVAL;
1172
1173         flags = sxdp->sxdp_flags;
1174         if (flags & ~(XDP_SHARED_UMEM | XDP_COPY | XDP_ZEROCOPY |
1175                       XDP_USE_NEED_WAKEUP | XDP_USE_SG))
1176                 return -EINVAL;
1177
1178         bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
1179         if (bound_dev_if && bound_dev_if != sxdp->sxdp_ifindex)
1180                 return -EINVAL;
1181
1182         rtnl_lock();
1183         mutex_lock(&xs->mutex);
1184         if (xs->state != XSK_READY) {
1185                 err = -EBUSY;
1186                 goto out_release;
1187         }
1188
1189         dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);
1190         if (!dev) {
1191                 err = -ENODEV;
1192                 goto out_release;
1193         }
1194
1195         if (!xs->rx && !xs->tx) {
1196                 err = -EINVAL;
1197                 goto out_unlock;
1198         }
1199
1200         qid = sxdp->sxdp_queue_id;
1201
1202         if (flags & XDP_SHARED_UMEM) {
1203                 struct xdp_sock *umem_xs;
1204                 struct socket *sock;
1205
1206                 if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY) ||
1207                     (flags & XDP_USE_NEED_WAKEUP) || (flags & XDP_USE_SG)) {
1208                         /* Cannot specify flags for shared sockets. */
1209                         err = -EINVAL;
1210                         goto out_unlock;
1211                 }
1212
1213                 if (xs->umem) {
1214                         /* We have already our own. */
1215                         err = -EINVAL;
1216                         goto out_unlock;
1217                 }
1218
1219                 sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd);
1220                 if (IS_ERR(sock)) {
1221                         err = PTR_ERR(sock);
1222                         goto out_unlock;
1223                 }
1224
1225                 umem_xs = xdp_sk(sock->sk);
1226                 if (!xsk_is_bound(umem_xs)) {
1227                         err = -EBADF;
1228                         sockfd_put(sock);
1229                         goto out_unlock;
1230                 }
1231
1232                 if (umem_xs->queue_id != qid || umem_xs->dev != dev) {
1233                         /* Share the umem with another socket on another qid
1234                          * and/or device.
1235                          */
1236                         xs->pool = xp_create_and_assign_umem(xs,
1237                                                              umem_xs->umem);
1238                         if (!xs->pool) {
1239                                 err = -ENOMEM;
1240                                 sockfd_put(sock);
1241                                 goto out_unlock;
1242                         }
1243
1244                         err = xp_assign_dev_shared(xs->pool, umem_xs, dev,
1245                                                    qid);
1246                         if (err) {
1247                                 xp_destroy(xs->pool);
1248                                 xs->pool = NULL;
1249                                 sockfd_put(sock);
1250                                 goto out_unlock;
1251                         }
1252                 } else {
1253                         /* Share the buffer pool with the other socket. */
1254                         if (xs->fq_tmp || xs->cq_tmp) {
1255                                 /* Do not allow setting your own fq or cq. */
1256                                 err = -EINVAL;
1257                                 sockfd_put(sock);
1258                                 goto out_unlock;
1259                         }
1260
1261                         xp_get_pool(umem_xs->pool);
1262                         xs->pool = umem_xs->pool;
1263
1264                         /* If underlying shared umem was created without Tx
1265                          * ring, allocate Tx descs array that Tx batching API
1266                          * utilizes
1267                          */
1268                         if (xs->tx && !xs->pool->tx_descs) {
1269                                 err = xp_alloc_tx_descs(xs->pool, xs);
1270                                 if (err) {
1271                                         xp_put_pool(xs->pool);
1272                                         xs->pool = NULL;
1273                                         sockfd_put(sock);
1274                                         goto out_unlock;
1275                                 }
1276                         }
1277                 }
1278
1279                 xdp_get_umem(umem_xs->umem);
1280                 WRITE_ONCE(xs->umem, umem_xs->umem);
1281                 sockfd_put(sock);
1282         } else if (!xs->umem || !xsk_validate_queues(xs)) {
1283                 err = -EINVAL;
1284                 goto out_unlock;
1285         } else {
1286                 /* This xsk has its own umem. */
1287                 xs->pool = xp_create_and_assign_umem(xs, xs->umem);
1288                 if (!xs->pool) {
1289                         err = -ENOMEM;
1290                         goto out_unlock;
1291                 }
1292
1293                 err = xp_assign_dev(xs->pool, dev, qid, flags);
1294                 if (err) {
1295                         xp_destroy(xs->pool);
1296                         xs->pool = NULL;
1297                         goto out_unlock;
1298                 }
1299         }
1300
1301         /* FQ and CQ are now owned by the buffer pool and cleaned up with it. */
1302         xs->fq_tmp = NULL;
1303         xs->cq_tmp = NULL;
1304
1305         xs->dev = dev;
1306         xs->zc = xs->umem->zc;
1307         xs->sg = !!(xs->umem->flags & XDP_UMEM_SG_FLAG);
1308         xs->queue_id = qid;
1309         xp_add_xsk(xs->pool, xs);
1310
1311 out_unlock:
1312         if (err) {
1313                 dev_put(dev);
1314         } else {
1315                 /* Matches smp_rmb() in bind() for shared umem
1316                  * sockets, and xsk_is_bound().
1317                  */
1318                 smp_wmb();
1319                 WRITE_ONCE(xs->state, XSK_BOUND);
1320         }
1321 out_release:
1322         mutex_unlock(&xs->mutex);
1323         rtnl_unlock();
1324         return err;
1325 }
1326
1327 struct xdp_umem_reg_v1 {
1328         __u64 addr; /* Start of packet data area */
1329         __u64 len; /* Length of packet data area */
1330         __u32 chunk_size;
1331         __u32 headroom;
1332 };
1333
1334 struct xdp_umem_reg_v2 {
1335         __u64 addr; /* Start of packet data area */
1336         __u64 len; /* Length of packet data area */
1337         __u32 chunk_size;
1338         __u32 headroom;
1339         __u32 flags;
1340 };
1341
1342 static int xsk_setsockopt(struct socket *sock, int level, int optname,
1343                           sockptr_t optval, unsigned int optlen)
1344 {
1345         struct sock *sk = sock->sk;
1346         struct xdp_sock *xs = xdp_sk(sk);
1347         int err;
1348
1349         if (level != SOL_XDP)
1350                 return -ENOPROTOOPT;
1351
1352         switch (optname) {
1353         case XDP_RX_RING:
1354         case XDP_TX_RING:
1355         {
1356                 struct xsk_queue **q;
1357                 int entries;
1358
1359                 if (optlen < sizeof(entries))
1360                         return -EINVAL;
1361                 if (copy_from_sockptr(&entries, optval, sizeof(entries)))
1362                         return -EFAULT;
1363
1364                 mutex_lock(&xs->mutex);
1365                 if (xs->state != XSK_READY) {
1366                         mutex_unlock(&xs->mutex);
1367                         return -EBUSY;
1368                 }
1369                 q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx;
1370                 err = xsk_init_queue(entries, q, false);
1371                 if (!err && optname == XDP_TX_RING)
1372                         /* Tx needs to be explicitly woken up the first time */
1373                         xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
1374                 mutex_unlock(&xs->mutex);
1375                 return err;
1376         }
1377         case XDP_UMEM_REG:
1378         {
1379                 size_t mr_size = sizeof(struct xdp_umem_reg);
1380                 struct xdp_umem_reg mr = {};
1381                 struct xdp_umem *umem;
1382
1383                 if (optlen < sizeof(struct xdp_umem_reg_v1))
1384                         return -EINVAL;
1385                 else if (optlen < sizeof(struct xdp_umem_reg_v2))
1386                         mr_size = sizeof(struct xdp_umem_reg_v1);
1387                 else if (optlen < sizeof(mr))
1388                         mr_size = sizeof(struct xdp_umem_reg_v2);
1389
1390                 if (copy_from_sockptr(&mr, optval, mr_size))
1391                         return -EFAULT;
1392
1393                 mutex_lock(&xs->mutex);
1394                 if (xs->state != XSK_READY || xs->umem) {
1395                         mutex_unlock(&xs->mutex);
1396                         return -EBUSY;
1397                 }
1398
1399                 umem = xdp_umem_create(&mr);
1400                 if (IS_ERR(umem)) {
1401                         mutex_unlock(&xs->mutex);
1402                         return PTR_ERR(umem);
1403                 }
1404
1405                 /* Make sure umem is ready before it can be seen by others */
1406                 smp_wmb();
1407                 WRITE_ONCE(xs->umem, umem);
1408                 mutex_unlock(&xs->mutex);
1409                 return 0;
1410         }
1411         case XDP_UMEM_FILL_RING:
1412         case XDP_UMEM_COMPLETION_RING:
1413         {
1414                 struct xsk_queue **q;
1415                 int entries;
1416
1417                 if (optlen < sizeof(entries))
1418                         return -EINVAL;
1419                 if (copy_from_sockptr(&entries, optval, sizeof(entries)))
1420                         return -EFAULT;
1421
1422                 mutex_lock(&xs->mutex);
1423                 if (xs->state != XSK_READY) {
1424                         mutex_unlock(&xs->mutex);
1425                         return -EBUSY;
1426                 }
1427
1428                 q = (optname == XDP_UMEM_FILL_RING) ? &xs->fq_tmp :
1429                         &xs->cq_tmp;
1430                 err = xsk_init_queue(entries, q, true);
1431                 mutex_unlock(&xs->mutex);
1432                 return err;
1433         }
1434         default:
1435                 break;
1436         }
1437
1438         return -ENOPROTOOPT;
1439 }
1440
1441 static void xsk_enter_rxtx_offsets(struct xdp_ring_offset_v1 *ring)
1442 {
1443         ring->producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
1444         ring->consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
1445         ring->desc = offsetof(struct xdp_rxtx_ring, desc);
1446 }
1447
1448 static void xsk_enter_umem_offsets(struct xdp_ring_offset_v1 *ring)
1449 {
1450         ring->producer = offsetof(struct xdp_umem_ring, ptrs.producer);
1451         ring->consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
1452         ring->desc = offsetof(struct xdp_umem_ring, desc);
1453 }
1454
1455 struct xdp_statistics_v1 {
1456         __u64 rx_dropped;
1457         __u64 rx_invalid_descs;
1458         __u64 tx_invalid_descs;
1459 };
1460
1461 static int xsk_getsockopt(struct socket *sock, int level, int optname,
1462                           char __user *optval, int __user *optlen)
1463 {
1464         struct sock *sk = sock->sk;
1465         struct xdp_sock *xs = xdp_sk(sk);
1466         int len;
1467
1468         if (level != SOL_XDP)
1469                 return -ENOPROTOOPT;
1470
1471         if (get_user(len, optlen))
1472                 return -EFAULT;
1473         if (len < 0)
1474                 return -EINVAL;
1475
1476         switch (optname) {
1477         case XDP_STATISTICS:
1478         {
1479                 struct xdp_statistics stats = {};
1480                 bool extra_stats = true;
1481                 size_t stats_size;
1482
1483                 if (len < sizeof(struct xdp_statistics_v1)) {
1484                         return -EINVAL;
1485                 } else if (len < sizeof(stats)) {
1486                         extra_stats = false;
1487                         stats_size = sizeof(struct xdp_statistics_v1);
1488                 } else {
1489                         stats_size = sizeof(stats);
1490                 }
1491
1492                 mutex_lock(&xs->mutex);
1493                 stats.rx_dropped = xs->rx_dropped;
1494                 if (extra_stats) {
1495                         stats.rx_ring_full = xs->rx_queue_full;
1496                         stats.rx_fill_ring_empty_descs =
1497                                 xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;
1498                         stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
1499                 } else {
1500                         stats.rx_dropped += xs->rx_queue_full;
1501                 }
1502                 stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
1503                 stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
1504                 mutex_unlock(&xs->mutex);
1505
1506                 if (copy_to_user(optval, &stats, stats_size))
1507                         return -EFAULT;
1508                 if (put_user(stats_size, optlen))
1509                         return -EFAULT;
1510
1511                 return 0;
1512         }
1513         case XDP_MMAP_OFFSETS:
1514         {
1515                 struct xdp_mmap_offsets off;
1516                 struct xdp_mmap_offsets_v1 off_v1;
1517                 bool flags_supported = true;
1518                 void *to_copy;
1519
1520                 if (len < sizeof(off_v1))
1521                         return -EINVAL;
1522                 else if (len < sizeof(off))
1523                         flags_supported = false;
1524
1525                 if (flags_supported) {
1526                         /* xdp_ring_offset is identical to xdp_ring_offset_v1
1527                          * except for the flags field added to the end.
1528                          */
1529                         xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1530                                                &off.rx);
1531                         xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1532                                                &off.tx);
1533                         xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1534                                                &off.fr);
1535                         xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1536                                                &off.cr);
1537                         off.rx.flags = offsetof(struct xdp_rxtx_ring,
1538                                                 ptrs.flags);
1539                         off.tx.flags = offsetof(struct xdp_rxtx_ring,
1540                                                 ptrs.flags);
1541                         off.fr.flags = offsetof(struct xdp_umem_ring,
1542                                                 ptrs.flags);
1543                         off.cr.flags = offsetof(struct xdp_umem_ring,
1544                                                 ptrs.flags);
1545
1546                         len = sizeof(off);
1547                         to_copy = &off;
1548                 } else {
1549                         xsk_enter_rxtx_offsets(&off_v1.rx);
1550                         xsk_enter_rxtx_offsets(&off_v1.tx);
1551                         xsk_enter_umem_offsets(&off_v1.fr);
1552                         xsk_enter_umem_offsets(&off_v1.cr);
1553
1554                         len = sizeof(off_v1);
1555                         to_copy = &off_v1;
1556                 }
1557
1558                 if (copy_to_user(optval, to_copy, len))
1559                         return -EFAULT;
1560                 if (put_user(len, optlen))
1561                         return -EFAULT;
1562
1563                 return 0;
1564         }
1565         case XDP_OPTIONS:
1566         {
1567                 struct xdp_options opts = {};
1568
1569                 if (len < sizeof(opts))
1570                         return -EINVAL;
1571
1572                 mutex_lock(&xs->mutex);
1573                 if (xs->zc)
1574                         opts.flags |= XDP_OPTIONS_ZEROCOPY;
1575                 mutex_unlock(&xs->mutex);
1576
1577                 len = sizeof(opts);
1578                 if (copy_to_user(optval, &opts, len))
1579                         return -EFAULT;
1580                 if (put_user(len, optlen))
1581                         return -EFAULT;
1582
1583                 return 0;
1584         }
1585         default:
1586                 break;
1587         }
1588
1589         return -EOPNOTSUPP;
1590 }
1591
1592 static int xsk_mmap(struct file *file, struct socket *sock,
1593                     struct vm_area_struct *vma)
1594 {
1595         loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
1596         unsigned long size = vma->vm_end - vma->vm_start;
1597         struct xdp_sock *xs = xdp_sk(sock->sk);
1598         int state = READ_ONCE(xs->state);
1599         struct xsk_queue *q = NULL;
1600
1601         if (state != XSK_READY && state != XSK_BOUND)
1602                 return -EBUSY;
1603
1604         if (offset == XDP_PGOFF_RX_RING) {
1605                 q = READ_ONCE(xs->rx);
1606         } else if (offset == XDP_PGOFF_TX_RING) {
1607                 q = READ_ONCE(xs->tx);
1608         } else {
1609                 /* Matches the smp_wmb() in XDP_UMEM_REG */
1610                 smp_rmb();
1611                 if (offset == XDP_UMEM_PGOFF_FILL_RING)
1612                         q = state == XSK_READY ? READ_ONCE(xs->fq_tmp) :
1613                                                  READ_ONCE(xs->pool->fq);
1614                 else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
1615                         q = state == XSK_READY ? READ_ONCE(xs->cq_tmp) :
1616                                                  READ_ONCE(xs->pool->cq);
1617         }
1618
1619         if (!q)
1620                 return -EINVAL;
1621
1622         /* Matches the smp_wmb() in xsk_init_queue */
1623         smp_rmb();
1624         if (size > q->ring_vmalloc_size)
1625                 return -EINVAL;
1626
1627         return remap_vmalloc_range(vma, q->ring, 0);
1628 }
1629
1630 static int xsk_notifier(struct notifier_block *this,
1631                         unsigned long msg, void *ptr)
1632 {
1633         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1634         struct net *net = dev_net(dev);
1635         struct sock *sk;
1636
1637         switch (msg) {
1638         case NETDEV_UNREGISTER:
1639                 mutex_lock(&net->xdp.lock);
1640                 sk_for_each(sk, &net->xdp.list) {
1641                         struct xdp_sock *xs = xdp_sk(sk);
1642
1643                         mutex_lock(&xs->mutex);
1644                         if (xs->dev == dev) {
1645                                 sk->sk_err = ENETDOWN;
1646                                 if (!sock_flag(sk, SOCK_DEAD))
1647                                         sk_error_report(sk);
1648
1649                                 xsk_unbind_dev(xs);
1650
1651                                 /* Clear device references. */
1652                                 xp_clear_dev(xs->pool);
1653                         }
1654                         mutex_unlock(&xs->mutex);
1655                 }
1656                 mutex_unlock(&net->xdp.lock);
1657                 break;
1658         }
1659         return NOTIFY_DONE;
1660 }
1661
1662 static struct proto xsk_proto = {
1663         .name =         "XDP",
1664         .owner =        THIS_MODULE,
1665         .obj_size =     sizeof(struct xdp_sock),
1666 };
1667
1668 static const struct proto_ops xsk_proto_ops = {
1669         .family         = PF_XDP,
1670         .owner          = THIS_MODULE,
1671         .release        = xsk_release,
1672         .bind           = xsk_bind,
1673         .connect        = sock_no_connect,
1674         .socketpair     = sock_no_socketpair,
1675         .accept         = sock_no_accept,
1676         .getname        = sock_no_getname,
1677         .poll           = xsk_poll,
1678         .ioctl          = sock_no_ioctl,
1679         .listen         = sock_no_listen,
1680         .shutdown       = sock_no_shutdown,
1681         .setsockopt     = xsk_setsockopt,
1682         .getsockopt     = xsk_getsockopt,
1683         .sendmsg        = xsk_sendmsg,
1684         .recvmsg        = xsk_recvmsg,
1685         .mmap           = xsk_mmap,
1686 };
1687
1688 static void xsk_destruct(struct sock *sk)
1689 {
1690         struct xdp_sock *xs = xdp_sk(sk);
1691
1692         if (!sock_flag(sk, SOCK_DEAD))
1693                 return;
1694
1695         if (!xp_put_pool(xs->pool))
1696                 xdp_put_umem(xs->umem, !xs->pool);
1697 }
1698
1699 static int xsk_create(struct net *net, struct socket *sock, int protocol,
1700                       int kern)
1701 {
1702         struct xdp_sock *xs;
1703         struct sock *sk;
1704
1705         if (!ns_capable(net->user_ns, CAP_NET_RAW))
1706                 return -EPERM;
1707         if (sock->type != SOCK_RAW)
1708                 return -ESOCKTNOSUPPORT;
1709
1710         if (protocol)
1711                 return -EPROTONOSUPPORT;
1712
1713         sock->state = SS_UNCONNECTED;
1714
1715         sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern);
1716         if (!sk)
1717                 return -ENOBUFS;
1718
1719         sock->ops = &xsk_proto_ops;
1720
1721         sock_init_data(sock, sk);
1722
1723         sk->sk_family = PF_XDP;
1724
1725         sk->sk_destruct = xsk_destruct;
1726
1727         sock_set_flag(sk, SOCK_RCU_FREE);
1728
1729         xs = xdp_sk(sk);
1730         xs->state = XSK_READY;
1731         mutex_init(&xs->mutex);
1732         spin_lock_init(&xs->rx_lock);
1733
1734         INIT_LIST_HEAD(&xs->map_list);
1735         spin_lock_init(&xs->map_list_lock);
1736
1737         mutex_lock(&net->xdp.lock);
1738         sk_add_node_rcu(sk, &net->xdp.list);
1739         mutex_unlock(&net->xdp.lock);
1740
1741         sock_prot_inuse_add(net, &xsk_proto, 1);
1742
1743         return 0;
1744 }
1745
1746 static const struct net_proto_family xsk_family_ops = {
1747         .family = PF_XDP,
1748         .create = xsk_create,
1749         .owner  = THIS_MODULE,
1750 };
1751
1752 static struct notifier_block xsk_netdev_notifier = {
1753         .notifier_call  = xsk_notifier,
1754 };
1755
1756 static int __net_init xsk_net_init(struct net *net)
1757 {
1758         mutex_init(&net->xdp.lock);
1759         INIT_HLIST_HEAD(&net->xdp.list);
1760         return 0;
1761 }
1762
1763 static void __net_exit xsk_net_exit(struct net *net)
1764 {
1765         WARN_ON_ONCE(!hlist_empty(&net->xdp.list));
1766 }
1767
1768 static struct pernet_operations xsk_net_ops = {
1769         .init = xsk_net_init,
1770         .exit = xsk_net_exit,
1771 };
1772
1773 static int __init xsk_init(void)
1774 {
1775         int err, cpu;
1776
1777         err = proto_register(&xsk_proto, 0 /* no slab */);
1778         if (err)
1779                 goto out;
1780
1781         err = sock_register(&xsk_family_ops);
1782         if (err)
1783                 goto out_proto;
1784
1785         err = register_pernet_subsys(&xsk_net_ops);
1786         if (err)
1787                 goto out_sk;
1788
1789         err = register_netdevice_notifier(&xsk_netdev_notifier);
1790         if (err)
1791                 goto out_pernet;
1792
1793         for_each_possible_cpu(cpu)
1794                 INIT_LIST_HEAD(&per_cpu(xskmap_flush_list, cpu));
1795         return 0;
1796
1797 out_pernet:
1798         unregister_pernet_subsys(&xsk_net_ops);
1799 out_sk:
1800         sock_unregister(PF_XDP);
1801 out_proto:
1802         proto_unregister(&xsk_proto);
1803 out:
1804         return err;
1805 }
1806
1807 fs_initcall(xsk_init);