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