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)
 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, 0);
 726                 }
 727
 728                 if (first_frag && desc->options & XDP_TX_METADATA) {
 729                         if (unlikely(xs->pool->tx_metadata_len == 0)) {
 730                                 err = -EINVAL;
 731                                 goto free_err;
 732                         }
 733
 734                         meta = buffer - xs->pool->tx_metadata_len;
 735                         if (unlikely(!xsk_buff_valid_tx_metadata(meta))) {
 736                                 err = -EINVAL;
 737                                 goto free_err;
 738                         }
 739
 740                         if (meta->flags & XDP_TXMD_FLAGS_CHECKSUM) {
 741                                 if (unlikely(meta->request.csum_start +
 742                                              meta->request.csum_offset +
 743                                              sizeof(__sum16) > len)) {
 744                                         err = -EINVAL;
 745                                         goto free_err;
 746                                 }
 747
 748                                 skb->csum_start = hr + meta->request.csum_start;
 749                                 skb->csum_offset = meta->request.csum_offset;
 750                                 skb->ip_summed = CHECKSUM_PARTIAL;
 751
 752                                 if (unlikely(xs->pool->tx_sw_csum)) {
 753                                         err = skb_checksum_help(skb);
 754                                         if (err)
 755                                                 goto free_err;
 756                                 }
 757                         }
 758                 }
 759         }
 760
 761         skb->dev = dev;
 762         skb->priority = READ_ONCE(xs->sk.sk_priority);
 763         skb->mark = READ_ONCE(xs->sk.sk_mark);
 764         skb->destructor = xsk_destruct_skb;
 765         xsk_tx_metadata_to_compl(meta, &skb_shinfo(skb)->xsk_meta);
 766         xsk_set_destructor_arg(skb);
 767
 768         return skb;
 769
 770 free_err:
 771         if (err == -EOVERFLOW) {
 772                 /* Drop the packet */
 773                 xsk_set_destructor_arg(xs->skb);
 774                 xsk_drop_skb(xs->skb);
 775                 xskq_cons_release(xs->tx);
 776         } else {
 777                 /* Let application retry */
 778                 xsk_cq_cancel_locked(xs, 1);
 779         }
 780
 781         return ERR_PTR(err);
 782 }
 783
 784 static int __xsk_generic_xmit(struct sock *sk)
 785 {
 786         struct xdp_sock *xs = xdp_sk(sk);
 787         u32 max_batch = TX_BATCH_SIZE;
 788         bool sent_frame = false;
 789         struct xdp_desc desc;
 790         struct sk_buff *skb;
 791         int err = 0;
 792
 793         mutex_lock(&xs->mutex);
 794
 795         /* Since we dropped the RCU read lock, the socket state might have changed. */
 796         if (unlikely(!xsk_is_bound(xs))) {
 797                 err = -ENXIO;
 798                 goto out;
 799         }
 800
 801         if (xs->queue_id >= xs->dev->real_num_tx_queues)
 802                 goto out;
 803
 804         while (xskq_cons_peek_desc(xs->tx, &desc, xs->pool)) {
 805                 if (max_batch-- == 0) {
 806                         err = -EAGAIN;
 807                         goto out;
 808                 }
 809
 810                 /* This is the backpressure mechanism for the Tx path.
 811                  * Reserve space in the completion queue and only proceed
 812                  * if there is space in it. This avoids having to implement
 813                  * any buffering in the Tx path.
 814                  */
 815                 if (xsk_cq_reserve_addr_locked(xs, desc.addr))
 816                         goto out;
 817
 818                 skb = xsk_build_skb(xs, &desc);
 819                 if (IS_ERR(skb)) {
 820                         err = PTR_ERR(skb);
 821                         if (err != -EOVERFLOW)
 822                                 goto out;
 823                         err = 0;
 824                         continue;
 825                 }
 826
 827                 xskq_cons_release(xs->tx);
 828
 829                 if (xp_mb_desc(&desc)) {
 830                         xs->skb = skb;
 831                         continue;
 832                 }
 833
 834                 err = __dev_direct_xmit(skb, xs->queue_id);
 835                 if  (err == NETDEV_TX_BUSY) {
 836                         /* Tell user-space to retry the send */
 837                         xskq_cons_cancel_n(xs->tx, xsk_get_num_desc(skb));
 838                         xsk_consume_skb(skb);
 839                         err = -EAGAIN;
 840                         goto out;
 841                 }
 842
 843                 /* Ignore NET_XMIT_CN as packet might have been sent */
 844                 if (err == NET_XMIT_DROP) {
 845                         /* SKB completed but not sent */
 846                         err = -EBUSY;
 847                         xs->skb = NULL;
 848                         goto out;
 849                 }
 850
 851                 sent_frame = true;
 852                 xs->skb = NULL;
 853         }
 854
 855         if (xskq_has_descs(xs->tx)) {
 856                 if (xs->skb)
 857                         xsk_drop_skb(xs->skb);
 858                 xskq_cons_release(xs->tx);
 859         }
 860
 861 out:
 862         if (sent_frame)
 863                 if (xsk_tx_writeable(xs))
 864                         sk->sk_write_space(sk);
 865
 866         mutex_unlock(&xs->mutex);
 867         return err;
 868 }
 869
 870 static int xsk_generic_xmit(struct sock *sk)
 871 {
 872         int ret;
 873
 874         /* Drop the RCU lock since the SKB path might sleep. */
 875         rcu_read_unlock();
 876         ret = __xsk_generic_xmit(sk);
 877         /* Reaquire RCU lock before going into common code. */
 878         rcu_read_lock();
 879
 880         return ret;
 881 }
 882
 883 static bool xsk_no_wakeup(struct sock *sk)
 884 {
 885 #ifdef CONFIG_NET_RX_BUSY_POLL
 886         /* Prefer busy-polling, skip the wakeup. */
 887         return READ_ONCE(sk->sk_prefer_busy_poll) && READ_ONCE(sk->sk_ll_usec) &&
 888                 READ_ONCE(sk->sk_napi_id) >= MIN_NAPI_ID;
 889 #else
 890         return false;
 891 #endif
 892 }
 893
 894 static int xsk_check_common(struct xdp_sock *xs)
 895 {
 896         if (unlikely(!xsk_is_bound(xs)))
 897                 return -ENXIO;
 898         if (unlikely(!(xs->dev->flags & IFF_UP)))
 899                 return -ENETDOWN;
 900
 901         return 0;
 902 }
 903
 904 static int __xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 905 {
 906         bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
 907         struct sock *sk = sock->sk;
 908         struct xdp_sock *xs = xdp_sk(sk);
 909         struct xsk_buff_pool *pool;
 910         int err;
 911
 912         err = xsk_check_common(xs);
 913         if (err)
 914                 return err;
 915         if (unlikely(need_wait))
 916                 return -EOPNOTSUPP;
 917         if (unlikely(!xs->tx))
 918                 return -ENOBUFS;
 919
 920         if (sk_can_busy_loop(sk)) {
 921                 if (xs->zc)
 922                         __sk_mark_napi_id_once(sk, xsk_pool_get_napi_id(xs->pool));
 923                 sk_busy_loop(sk, 1); /* only support non-blocking sockets */
 924         }
 925
 926         if (xs->zc && xsk_no_wakeup(sk))
 927                 return 0;
 928
 929         pool = xs->pool;
 930         if (pool->cached_need_wakeup & XDP_WAKEUP_TX) {
 931                 if (xs->zc)
 932                         return xsk_wakeup(xs, XDP_WAKEUP_TX);
 933                 return xsk_generic_xmit(sk);
 934         }
 935         return 0;
 936 }
 937
 938 static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 939 {
 940         int ret;
 941
 942         rcu_read_lock();
 943         ret = __xsk_sendmsg(sock, m, total_len);
 944         rcu_read_unlock();
 945
 946         return ret;
 947 }
 948
 949 static int __xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
 950 {
 951         bool need_wait = !(flags & MSG_DONTWAIT);
 952         struct sock *sk = sock->sk;
 953         struct xdp_sock *xs = xdp_sk(sk);
 954         int err;
 955
 956         err = xsk_check_common(xs);
 957         if (err)
 958                 return err;
 959         if (unlikely(!xs->rx))
 960                 return -ENOBUFS;
 961         if (unlikely(need_wait))
 962                 return -EOPNOTSUPP;
 963
 964         if (sk_can_busy_loop(sk))
 965                 sk_busy_loop(sk, 1); /* only support non-blocking sockets */
 966
 967         if (xsk_no_wakeup(sk))
 968                 return 0;
 969
 970         if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc)
 971                 return xsk_wakeup(xs, XDP_WAKEUP_RX);
 972         return 0;
 973 }
 974
 975 static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
 976 {
 977         int ret;
 978
 979         rcu_read_lock();
 980         ret = __xsk_recvmsg(sock, m, len, flags);
 981         rcu_read_unlock();
 982
 983         return ret;
 984 }
 985
 986 static __poll_t xsk_poll(struct file *file, struct socket *sock,
 987                              struct poll_table_struct *wait)
 988 {
 989         __poll_t mask = 0;
 990         struct sock *sk = sock->sk;
 991         struct xdp_sock *xs = xdp_sk(sk);
 992         struct xsk_buff_pool *pool;
 993
 994         sock_poll_wait(file, sock, wait);
 995
 996         rcu_read_lock();
 997         if (xsk_check_common(xs))
 998                 goto out;
 999
1000         pool = xs->pool;
1001
1002         if (pool->cached_need_wakeup) {
1003                 if (xs->zc)
1004                         xsk_wakeup(xs, pool->cached_need_wakeup);
1005                 else if (xs->tx)
1006                         /* Poll needs to drive Tx also in copy mode */
1007                         xsk_generic_xmit(sk);
1008         }
1009
1010         if (xs->rx && !xskq_prod_is_empty(xs->rx))
1011                 mask |= EPOLLIN | EPOLLRDNORM;
1012         if (xs->tx && xsk_tx_writeable(xs))
1013                 mask |= EPOLLOUT | EPOLLWRNORM;
1014 out:
1015         rcu_read_unlock();
1016         return mask;
1017 }
1018
1019 static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
1020                           bool umem_queue)
1021 {
1022         struct xsk_queue *q;
1023
1024         if (entries == 0 || *queue || !is_power_of_2(entries))
1025                 return -EINVAL;
1026
1027         q = xskq_create(entries, umem_queue);
1028         if (!q)
1029                 return -ENOMEM;
1030
1031         /* Make sure queue is ready before it can be seen by others */
1032         smp_wmb();
1033         WRITE_ONCE(*queue, q);
1034         return 0;
1035 }
1036
1037 static void xsk_unbind_dev(struct xdp_sock *xs)
1038 {
1039         struct net_device *dev = xs->dev;
1040
1041         if (xs->state != XSK_BOUND)
1042                 return;
1043         WRITE_ONCE(xs->state, XSK_UNBOUND);
1044
1045         /* Wait for driver to stop using the xdp socket. */
1046         xp_del_xsk(xs->pool, xs);
1047         synchronize_net();
1048         dev_put(dev);
1049 }
1050
1051 static struct xsk_map *xsk_get_map_list_entry(struct xdp_sock *xs,
1052                                               struct xdp_sock __rcu ***map_entry)
1053 {
1054         struct xsk_map *map = NULL;
1055         struct xsk_map_node *node;
1056
1057         *map_entry = NULL;
1058
1059         spin_lock_bh(&xs->map_list_lock);
1060         node = list_first_entry_or_null(&xs->map_list, struct xsk_map_node,
1061                                         node);
1062         if (node) {
1063                 bpf_map_inc(&node->map->map);
1064                 map = node->map;
1065                 *map_entry = node->map_entry;
1066         }
1067         spin_unlock_bh(&xs->map_list_lock);
1068         return map;
1069 }
1070
1071 static void xsk_delete_from_maps(struct xdp_sock *xs)
1072 {
1073         /* This function removes the current XDP socket from all the
1074          * maps it resides in. We need to take extra care here, due to
1075          * the two locks involved. Each map has a lock synchronizing
1076          * updates to the entries, and each socket has a lock that
1077          * synchronizes access to the list of maps (map_list). For
1078          * deadlock avoidance the locks need to be taken in the order
1079          * "map lock"->"socket map list lock". We start off by
1080          * accessing the socket map list, and take a reference to the
1081          * map to guarantee existence between the
1082          * xsk_get_map_list_entry() and xsk_map_try_sock_delete()
1083          * calls. Then we ask the map to remove the socket, which
1084          * tries to remove the socket from the map. Note that there
1085          * might be updates to the map between
1086          * xsk_get_map_list_entry() and xsk_map_try_sock_delete().
1087          */
1088         struct xdp_sock __rcu **map_entry = NULL;
1089         struct xsk_map *map;
1090
1091         while ((map = xsk_get_map_list_entry(xs, &map_entry))) {
1092                 xsk_map_try_sock_delete(map, xs, map_entry);
1093                 bpf_map_put(&map->map);
1094         }
1095 }
1096
1097 static int xsk_release(struct socket *sock)
1098 {
1099         struct sock *sk = sock->sk;
1100         struct xdp_sock *xs = xdp_sk(sk);
1101         struct net *net;
1102
1103         if (!sk)
1104                 return 0;
1105
1106         net = sock_net(sk);
1107
1108         if (xs->skb)
1109                 xsk_drop_skb(xs->skb);
1110
1111         mutex_lock(&net->xdp.lock);
1112         sk_del_node_init_rcu(sk);
1113         mutex_unlock(&net->xdp.lock);
1114
1115         sock_prot_inuse_add(net, sk->sk_prot, -1);
1116
1117         xsk_delete_from_maps(xs);
1118         mutex_lock(&xs->mutex);
1119         xsk_unbind_dev(xs);
1120         mutex_unlock(&xs->mutex);
1121
1122         xskq_destroy(xs->rx);
1123         xskq_destroy(xs->tx);
1124         xskq_destroy(xs->fq_tmp);
1125         xskq_destroy(xs->cq_tmp);
1126
1127         sock_orphan(sk);
1128         sock->sk = NULL;
1129
1130         sock_put(sk);
1131
1132         return 0;
1133 }
1134
1135 static struct socket *xsk_lookup_xsk_from_fd(int fd)
1136 {
1137         struct socket *sock;
1138         int err;
1139
1140         sock = sockfd_lookup(fd, &err);
1141         if (!sock)
1142                 return ERR_PTR(-ENOTSOCK);
1143
1144         if (sock->sk->sk_family != PF_XDP) {
1145                 sockfd_put(sock);
1146                 return ERR_PTR(-ENOPROTOOPT);
1147         }
1148
1149         return sock;
1150 }
1151
1152 static bool xsk_validate_queues(struct xdp_sock *xs)
1153 {
1154         return xs->fq_tmp && xs->cq_tmp;
1155 }
1156
1157 static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
1158 {
1159         struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr;
1160         struct sock *sk = sock->sk;
1161         struct xdp_sock *xs = xdp_sk(sk);
1162         struct net_device *dev;
1163         int bound_dev_if;
1164         u32 flags, qid;
1165         int err = 0;
1166
1167         if (addr_len < sizeof(struct sockaddr_xdp))
1168                 return -EINVAL;
1169         if (sxdp->sxdp_family != AF_XDP)
1170                 return -EINVAL;
1171
1172         flags = sxdp->sxdp_flags;
1173         if (flags & ~(XDP_SHARED_UMEM | XDP_COPY | XDP_ZEROCOPY |
1174                       XDP_USE_NEED_WAKEUP | XDP_USE_SG))
1175                 return -EINVAL;
1176
1177         bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
1178         if (bound_dev_if && bound_dev_if != sxdp->sxdp_ifindex)
1179                 return -EINVAL;
1180
1181         rtnl_lock();
1182         mutex_lock(&xs->mutex);
1183         if (xs->state != XSK_READY) {
1184                 err = -EBUSY;
1185                 goto out_release;
1186         }
1187
1188         dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);
1189         if (!dev) {
1190                 err = -ENODEV;
1191                 goto out_release;
1192         }
1193
1194         if (!xs->rx && !xs->tx) {
1195                 err = -EINVAL;
1196                 goto out_unlock;
1197         }
1198
1199         qid = sxdp->sxdp_queue_id;
1200
1201         if (flags & XDP_SHARED_UMEM) {
1202                 struct xdp_sock *umem_xs;
1203                 struct socket *sock;
1204
1205                 if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY) ||
1206                     (flags & XDP_USE_NEED_WAKEUP) || (flags & XDP_USE_SG)) {
1207                         /* Cannot specify flags for shared sockets. */
1208                         err = -EINVAL;
1209                         goto out_unlock;
1210                 }
1211
1212                 if (xs->umem) {
1213                         /* We have already our own. */
1214                         err = -EINVAL;
1215                         goto out_unlock;
1216                 }
1217
1218                 sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd);
1219                 if (IS_ERR(sock)) {
1220                         err = PTR_ERR(sock);
1221                         goto out_unlock;
1222                 }
1223
1224                 umem_xs = xdp_sk(sock->sk);
1225                 if (!xsk_is_bound(umem_xs)) {
1226                         err = -EBADF;
1227                         sockfd_put(sock);
1228                         goto out_unlock;
1229                 }
1230
1231                 if (umem_xs->queue_id != qid || umem_xs->dev != dev) {
1232                         /* Share the umem with another socket on another qid
1233                          * and/or device.
1234                          */
1235                         xs->pool = xp_create_and_assign_umem(xs,
1236                                                              umem_xs->umem);
1237                         if (!xs->pool) {
1238                                 err = -ENOMEM;
1239                                 sockfd_put(sock);
1240                                 goto out_unlock;
1241                         }
1242
1243                         err = xp_assign_dev_shared(xs->pool, umem_xs, dev,
1244                                                    qid);
1245                         if (err) {
1246                                 xp_destroy(xs->pool);
1247                                 xs->pool = NULL;
1248                                 sockfd_put(sock);
1249                                 goto out_unlock;
1250                         }
1251                 } else {
1252                         /* Share the buffer pool with the other socket. */
1253                         if (xs->fq_tmp || xs->cq_tmp) {
1254                                 /* Do not allow setting your own fq or cq. */
1255                                 err = -EINVAL;
1256                                 sockfd_put(sock);
1257                                 goto out_unlock;
1258                         }
1259
1260                         xp_get_pool(umem_xs->pool);
1261                         xs->pool = umem_xs->pool;
1262
1263                         /* If underlying shared umem was created without Tx
1264                          * ring, allocate Tx descs array that Tx batching API
1265                          * utilizes
1266                          */
1267                         if (xs->tx && !xs->pool->tx_descs) {
1268                                 err = xp_alloc_tx_descs(xs->pool, xs);
1269                                 if (err) {
1270                                         xp_put_pool(xs->pool);
1271                                         xs->pool = NULL;
1272                                         sockfd_put(sock);
1273                                         goto out_unlock;
1274                                 }
1275                         }
1276                 }
1277
1278                 xdp_get_umem(umem_xs->umem);
1279                 WRITE_ONCE(xs->umem, umem_xs->umem);
1280                 sockfd_put(sock);
1281         } else if (!xs->umem || !xsk_validate_queues(xs)) {
1282                 err = -EINVAL;
1283                 goto out_unlock;
1284         } else {
1285                 /* This xsk has its own umem. */
1286                 xs->pool = xp_create_and_assign_umem(xs, xs->umem);
1287                 if (!xs->pool) {
1288                         err = -ENOMEM;
1289                         goto out_unlock;
1290                 }
1291
1292                 err = xp_assign_dev(xs->pool, dev, qid, flags);
1293                 if (err) {
1294                         xp_destroy(xs->pool);
1295                         xs->pool = NULL;
1296                         goto out_unlock;
1297                 }
1298         }
1299
1300         /* FQ and CQ are now owned by the buffer pool and cleaned up with it. */
1301         xs->fq_tmp = NULL;
1302         xs->cq_tmp = NULL;
1303
1304         xs->dev = dev;
1305         xs->zc = xs->umem->zc;
1306         xs->sg = !!(xs->umem->flags & XDP_UMEM_SG_FLAG);
1307         xs->queue_id = qid;
1308         xp_add_xsk(xs->pool, xs);
1309
1310 out_unlock:
1311         if (err) {
1312                 dev_put(dev);
1313         } else {
1314                 /* Matches smp_rmb() in bind() for shared umem
1315                  * sockets, and xsk_is_bound().
1316                  */
1317                 smp_wmb();
1318                 WRITE_ONCE(xs->state, XSK_BOUND);
1319         }
1320 out_release:
1321         mutex_unlock(&xs->mutex);
1322         rtnl_unlock();
1323         return err;
1324 }
1325
1326 struct xdp_umem_reg_v1 {
1327         __u64 addr; /* Start of packet data area */
1328         __u64 len; /* Length of packet data area */
1329         __u32 chunk_size;
1330         __u32 headroom;
1331 };
1332
1333 struct xdp_umem_reg_v2 {
1334         __u64 addr; /* Start of packet data area */
1335         __u64 len; /* Length of packet data area */
1336         __u32 chunk_size;
1337         __u32 headroom;
1338         __u32 flags;
1339 };
1340
1341 static int xsk_setsockopt(struct socket *sock, int level, int optname,
1342                           sockptr_t optval, unsigned int optlen)
1343 {
1344         struct sock *sk = sock->sk;
1345         struct xdp_sock *xs = xdp_sk(sk);
1346         int err;
1347
1348         if (level != SOL_XDP)
1349                 return -ENOPROTOOPT;
1350
1351         switch (optname) {
1352         case XDP_RX_RING:
1353         case XDP_TX_RING:
1354         {
1355                 struct xsk_queue **q;
1356                 int entries;
1357
1358                 if (optlen < sizeof(entries))
1359                         return -EINVAL;
1360                 if (copy_from_sockptr(&entries, optval, sizeof(entries)))
1361                         return -EFAULT;
1362
1363                 mutex_lock(&xs->mutex);
1364                 if (xs->state != XSK_READY) {
1365                         mutex_unlock(&xs->mutex);
1366                         return -EBUSY;
1367                 }
1368                 q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx;
1369                 err = xsk_init_queue(entries, q, false);
1370                 if (!err && optname == XDP_TX_RING)
1371                         /* Tx needs to be explicitly woken up the first time */
1372                         xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
1373                 mutex_unlock(&xs->mutex);
1374                 return err;
1375         }
1376         case XDP_UMEM_REG:
1377         {
1378                 size_t mr_size = sizeof(struct xdp_umem_reg);
1379                 struct xdp_umem_reg mr = {};
1380                 struct xdp_umem *umem;
1381
1382                 if (optlen < sizeof(struct xdp_umem_reg_v1))
1383                         return -EINVAL;
1384                 else if (optlen < sizeof(struct xdp_umem_reg_v2))
1385                         mr_size = sizeof(struct xdp_umem_reg_v1);
1386                 else if (optlen < sizeof(mr))
1387                         mr_size = sizeof(struct xdp_umem_reg_v2);
1388
1389                 if (copy_from_sockptr(&mr, optval, mr_size))
1390                         return -EFAULT;
1391
1392                 mutex_lock(&xs->mutex);
1393                 if (xs->state != XSK_READY || xs->umem) {
1394                         mutex_unlock(&xs->mutex);
1395                         return -EBUSY;
1396                 }
1397
1398                 umem = xdp_umem_create(&mr);
1399                 if (IS_ERR(umem)) {
1400                         mutex_unlock(&xs->mutex);
1401                         return PTR_ERR(umem);
1402                 }
1403
1404                 /* Make sure umem is ready before it can be seen by others */
1405                 smp_wmb();
1406                 WRITE_ONCE(xs->umem, umem);
1407                 mutex_unlock(&xs->mutex);
1408                 return 0;
1409         }
1410         case XDP_UMEM_FILL_RING:
1411         case XDP_UMEM_COMPLETION_RING:
1412         {
1413                 struct xsk_queue **q;
1414                 int entries;
1415
1416                 if (copy_from_sockptr(&entries, optval, sizeof(entries)))
1417                         return -EFAULT;
1418
1419                 mutex_lock(&xs->mutex);
1420                 if (xs->state != XSK_READY) {
1421                         mutex_unlock(&xs->mutex);
1422                         return -EBUSY;
1423                 }
1424
1425                 q = (optname == XDP_UMEM_FILL_RING) ? &xs->fq_tmp :
1426                         &xs->cq_tmp;
1427                 err = xsk_init_queue(entries, q, true);
1428                 mutex_unlock(&xs->mutex);
1429                 return err;
1430         }
1431         default:
1432                 break;
1433         }
1434
1435         return -ENOPROTOOPT;
1436 }
1437
1438 static void xsk_enter_rxtx_offsets(struct xdp_ring_offset_v1 *ring)
1439 {
1440         ring->producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
1441         ring->consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
1442         ring->desc = offsetof(struct xdp_rxtx_ring, desc);
1443 }
1444
1445 static void xsk_enter_umem_offsets(struct xdp_ring_offset_v1 *ring)
1446 {
1447         ring->producer = offsetof(struct xdp_umem_ring, ptrs.producer);
1448         ring->consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
1449         ring->desc = offsetof(struct xdp_umem_ring, desc);
1450 }
1451
1452 struct xdp_statistics_v1 {
1453         __u64 rx_dropped;
1454         __u64 rx_invalid_descs;
1455         __u64 tx_invalid_descs;
1456 };
1457
1458 static int xsk_getsockopt(struct socket *sock, int level, int optname,
1459                           char __user *optval, int __user *optlen)
1460 {
1461         struct sock *sk = sock->sk;
1462         struct xdp_sock *xs = xdp_sk(sk);
1463         int len;
1464
1465         if (level != SOL_XDP)
1466                 return -ENOPROTOOPT;
1467
1468         if (get_user(len, optlen))
1469                 return -EFAULT;
1470         if (len < 0)
1471                 return -EINVAL;
1472
1473         switch (optname) {
1474         case XDP_STATISTICS:
1475         {
1476                 struct xdp_statistics stats = {};
1477                 bool extra_stats = true;
1478                 size_t stats_size;
1479
1480                 if (len < sizeof(struct xdp_statistics_v1)) {
1481                         return -EINVAL;
1482                 } else if (len < sizeof(stats)) {
1483                         extra_stats = false;
1484                         stats_size = sizeof(struct xdp_statistics_v1);
1485                 } else {
1486                         stats_size = sizeof(stats);
1487                 }
1488
1489                 mutex_lock(&xs->mutex);
1490                 stats.rx_dropped = xs->rx_dropped;
1491                 if (extra_stats) {
1492                         stats.rx_ring_full = xs->rx_queue_full;
1493                         stats.rx_fill_ring_empty_descs =
1494                                 xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;
1495                         stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
1496                 } else {
1497                         stats.rx_dropped += xs->rx_queue_full;
1498                 }
1499                 stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
1500                 stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
1501                 mutex_unlock(&xs->mutex);
1502
1503                 if (copy_to_user(optval, &stats, stats_size))
1504                         return -EFAULT;
1505                 if (put_user(stats_size, optlen))
1506                         return -EFAULT;
1507
1508                 return 0;
1509         }
1510         case XDP_MMAP_OFFSETS:
1511         {
1512                 struct xdp_mmap_offsets off;
1513                 struct xdp_mmap_offsets_v1 off_v1;
1514                 bool flags_supported = true;
1515                 void *to_copy;
1516
1517                 if (len < sizeof(off_v1))
1518                         return -EINVAL;
1519                 else if (len < sizeof(off))
1520                         flags_supported = false;
1521
1522                 if (flags_supported) {
1523                         /* xdp_ring_offset is identical to xdp_ring_offset_v1
1524                          * except for the flags field added to the end.
1525                          */
1526                         xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1527                                                &off.rx);
1528                         xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1529                                                &off.tx);
1530                         xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1531                                                &off.fr);
1532                         xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1533                                                &off.cr);
1534                         off.rx.flags = offsetof(struct xdp_rxtx_ring,
1535                                                 ptrs.flags);
1536                         off.tx.flags = offsetof(struct xdp_rxtx_ring,
1537                                                 ptrs.flags);
1538                         off.fr.flags = offsetof(struct xdp_umem_ring,
1539                                                 ptrs.flags);
1540                         off.cr.flags = offsetof(struct xdp_umem_ring,
1541                                                 ptrs.flags);
1542
1543                         len = sizeof(off);
1544                         to_copy = &off;
1545                 } else {
1546                         xsk_enter_rxtx_offsets(&off_v1.rx);
1547                         xsk_enter_rxtx_offsets(&off_v1.tx);
1548                         xsk_enter_umem_offsets(&off_v1.fr);
1549                         xsk_enter_umem_offsets(&off_v1.cr);
1550
1551                         len = sizeof(off_v1);
1552                         to_copy = &off_v1;
1553                 }
1554
1555                 if (copy_to_user(optval, to_copy, len))
1556                         return -EFAULT;
1557                 if (put_user(len, optlen))
1558                         return -EFAULT;
1559
1560                 return 0;
1561         }
1562         case XDP_OPTIONS:
1563         {
1564                 struct xdp_options opts = {};
1565
1566                 if (len < sizeof(opts))
1567                         return -EINVAL;
1568
1569                 mutex_lock(&xs->mutex);
1570                 if (xs->zc)
1571                         opts.flags |= XDP_OPTIONS_ZEROCOPY;
1572                 mutex_unlock(&xs->mutex);
1573
1574                 len = sizeof(opts);
1575                 if (copy_to_user(optval, &opts, len))
1576                         return -EFAULT;
1577                 if (put_user(len, optlen))
1578                         return -EFAULT;
1579
1580                 return 0;
1581         }
1582         default:
1583                 break;
1584         }
1585
1586         return -EOPNOTSUPP;
1587 }
1588
1589 static int xsk_mmap(struct file *file, struct socket *sock,
1590                     struct vm_area_struct *vma)
1591 {
1592         loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
1593         unsigned long size = vma->vm_end - vma->vm_start;
1594         struct xdp_sock *xs = xdp_sk(sock->sk);
1595         int state = READ_ONCE(xs->state);
1596         struct xsk_queue *q = NULL;
1597
1598         if (state != XSK_READY && state != XSK_BOUND)
1599                 return -EBUSY;
1600
1601         if (offset == XDP_PGOFF_RX_RING) {
1602                 q = READ_ONCE(xs->rx);
1603         } else if (offset == XDP_PGOFF_TX_RING) {
1604                 q = READ_ONCE(xs->tx);
1605         } else {
1606                 /* Matches the smp_wmb() in XDP_UMEM_REG */
1607                 smp_rmb();
1608                 if (offset == XDP_UMEM_PGOFF_FILL_RING)
1609                         q = state == XSK_READY ? READ_ONCE(xs->fq_tmp) :
1610                                                  READ_ONCE(xs->pool->fq);
1611                 else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
1612                         q = state == XSK_READY ? READ_ONCE(xs->cq_tmp) :
1613                                                  READ_ONCE(xs->pool->cq);
1614         }
1615
1616         if (!q)
1617                 return -EINVAL;
1618
1619         /* Matches the smp_wmb() in xsk_init_queue */
1620         smp_rmb();
1621         if (size > q->ring_vmalloc_size)
1622                 return -EINVAL;
1623
1624         return remap_vmalloc_range(vma, q->ring, 0);
1625 }
1626
1627 static int xsk_notifier(struct notifier_block *this,
1628                         unsigned long msg, void *ptr)
1629 {
1630         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1631         struct net *net = dev_net(dev);
1632         struct sock *sk;
1633
1634         switch (msg) {
1635         case NETDEV_UNREGISTER:
1636                 mutex_lock(&net->xdp.lock);
1637                 sk_for_each(sk, &net->xdp.list) {
1638                         struct xdp_sock *xs = xdp_sk(sk);
1639
1640                         mutex_lock(&xs->mutex);
1641                         if (xs->dev == dev) {
1642                                 sk->sk_err = ENETDOWN;
1643                                 if (!sock_flag(sk, SOCK_DEAD))
1644                                         sk_error_report(sk);
1645
1646                                 xsk_unbind_dev(xs);
1647
1648                                 /* Clear device references. */
1649                                 xp_clear_dev(xs->pool);
1650                         }
1651                         mutex_unlock(&xs->mutex);
1652                 }
1653                 mutex_unlock(&net->xdp.lock);
1654                 break;
1655         }
1656         return NOTIFY_DONE;
1657 }
1658
1659 static struct proto xsk_proto = {
1660         .name =         "XDP",
1661         .owner =        THIS_MODULE,
1662         .obj_size =     sizeof(struct xdp_sock),
1663 };
1664
1665 static const struct proto_ops xsk_proto_ops = {
1666         .family         = PF_XDP,
1667         .owner          = THIS_MODULE,
1668         .release        = xsk_release,
1669         .bind           = xsk_bind,
1670         .connect        = sock_no_connect,
1671         .socketpair     = sock_no_socketpair,
1672         .accept         = sock_no_accept,
1673         .getname        = sock_no_getname,
1674         .poll           = xsk_poll,
1675         .ioctl          = sock_no_ioctl,
1676         .listen         = sock_no_listen,
1677         .shutdown       = sock_no_shutdown,
1678         .setsockopt     = xsk_setsockopt,
1679         .getsockopt     = xsk_getsockopt,
1680         .sendmsg        = xsk_sendmsg,
1681         .recvmsg        = xsk_recvmsg,
1682         .mmap           = xsk_mmap,
1683 };
1684
1685 static void xsk_destruct(struct sock *sk)
1686 {
1687         struct xdp_sock *xs = xdp_sk(sk);
1688
1689         if (!sock_flag(sk, SOCK_DEAD))
1690                 return;
1691
1692         if (!xp_put_pool(xs->pool))
1693                 xdp_put_umem(xs->umem, !xs->pool);
1694 }
1695
1696 static int xsk_create(struct net *net, struct socket *sock, int protocol,
1697                       int kern)
1698 {
1699         struct xdp_sock *xs;
1700         struct sock *sk;
1701
1702         if (!ns_capable(net->user_ns, CAP_NET_RAW))
1703                 return -EPERM;
1704         if (sock->type != SOCK_RAW)
1705                 return -ESOCKTNOSUPPORT;
1706
1707         if (protocol)
1708                 return -EPROTONOSUPPORT;
1709
1710         sock->state = SS_UNCONNECTED;
1711
1712         sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern);
1713         if (!sk)
1714                 return -ENOBUFS;
1715
1716         sock->ops = &xsk_proto_ops;
1717
1718         sock_init_data(sock, sk);
1719
1720         sk->sk_family = PF_XDP;
1721
1722         sk->sk_destruct = xsk_destruct;
1723
1724         sock_set_flag(sk, SOCK_RCU_FREE);
1725
1726         xs = xdp_sk(sk);
1727         xs->state = XSK_READY;
1728         mutex_init(&xs->mutex);
1729         spin_lock_init(&xs->rx_lock);
1730
1731         INIT_LIST_HEAD(&xs->map_list);
1732         spin_lock_init(&xs->map_list_lock);
1733
1734         mutex_lock(&net->xdp.lock);
1735         sk_add_node_rcu(sk, &net->xdp.list);
1736         mutex_unlock(&net->xdp.lock);
1737
1738         sock_prot_inuse_add(net, &xsk_proto, 1);
1739
1740         return 0;
1741 }
1742
1743 static const struct net_proto_family xsk_family_ops = {
1744         .family = PF_XDP,
1745         .create = xsk_create,
1746         .owner  = THIS_MODULE,
1747 };
1748
1749 static struct notifier_block xsk_netdev_notifier = {
1750         .notifier_call  = xsk_notifier,
1751 };
1752
1753 static int __net_init xsk_net_init(struct net *net)
1754 {
1755         mutex_init(&net->xdp.lock);
1756         INIT_HLIST_HEAD(&net->xdp.list);
1757         return 0;
1758 }
1759
1760 static void __net_exit xsk_net_exit(struct net *net)
1761 {
1762         WARN_ON_ONCE(!hlist_empty(&net->xdp.list));
1763 }
1764
1765 static struct pernet_operations xsk_net_ops = {
1766         .init = xsk_net_init,
1767         .exit = xsk_net_exit,
1768 };
1769
1770 static int __init xsk_init(void)
1771 {
1772         int err, cpu;
1773
1774         err = proto_register(&xsk_proto, 0 /* no slab */);
1775         if (err)
1776                 goto out;
1777
1778         err = sock_register(&xsk_family_ops);
1779         if (err)
1780                 goto out_proto;
1781
1782         err = register_pernet_subsys(&xsk_net_ops);
1783         if (err)
1784                 goto out_sk;
1785
1786         err = register_netdevice_notifier(&xsk_netdev_notifier);
1787         if (err)
1788                 goto out_pernet;
1789
1790         for_each_possible_cpu(cpu)
1791                 INIT_LIST_HEAD(&per_cpu(xskmap_flush_list, cpu));
1792         return 0;
1793
1794 out_pernet:
1795         unregister_pernet_subsys(&xsk_net_ops);
1796 out_sk:
1797         sock_unregister(PF_XDP);
1798 out_proto:
1799         proto_unregister(&xsk_proto);
1800 out:
1801         return err;
1802 }
1803
1804 fs_initcall(xsk_init);