drivers/net/ethernet/sfc/rx.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /****************************************************************************
   3  * Driver for Solarflare network controllers and boards
   4  * Copyright 2005-2006 Fen Systems Ltd.
   5  * Copyright 2005-2013 Solarflare Communications Inc.
   6  */
   7
   8 #include <linux/socket.h>
   9 #include <linux/in.h>
  10 #include <linux/slab.h>
  11 #include <linux/ip.h>
  12 #include <linux/ipv6.h>
  13 #include <linux/tcp.h>
  14 #include <linux/udp.h>
  15 #include <linux/prefetch.h>
  16 #include <linux/moduleparam.h>
  17 #include <linux/iommu.h>
  18 #include <net/ip.h>
  19 #include <net/checksum.h>
  20 #include <net/xdp.h>
  21 #include <linux/bpf_trace.h>
  22 #include "net_driver.h"
  23 #include "efx.h"
  24 #include "rx_common.h"
  25 #include "filter.h"
  26 #include "nic.h"
  27 #include "selftest.h"
  28 #include "workarounds.h"
  29
  30 /* Preferred number of descriptors to fill at once */
  31 #define EFX_RX_PREFERRED_BATCH 8U
  32
  33 /* Maximum rx prefix used by any architecture. */
  34 #define EFX_MAX_RX_PREFIX_SIZE 16
  35
  36 /* Size of buffer allocated for skb header area. */
  37 #define EFX_SKB_HEADERS  128u
  38
  39 /* Each packet can consume up to ceil(max_frame_len / buffer_size) buffers */
  40 #define EFX_RX_MAX_FRAGS DIV_ROUND_UP(EFX_MAX_FRAME_LEN(EFX_MAX_MTU), \
  41                                       EFX_RX_USR_BUF_SIZE)
  42
  43 static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
  44                                      struct efx_rx_buffer *rx_buf,
  45                                      int len)
  46 {
  47         struct efx_nic *efx = rx_queue->efx;
  48         unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
  49
  50         if (likely(len <= max_len))
  51                 return;
  52
  53         /* The packet must be discarded, but this is only a fatal error
  54          * if the caller indicated it was
  55          */
  56         rx_buf->flags |= EFX_RX_PKT_DISCARD;
  57
  58         if (net_ratelimit())
  59                 netif_err(efx, rx_err, efx->net_dev,
  60                           "RX queue %d overlength RX event (%#x > %#x)\n",
  61                           efx_rx_queue_index(rx_queue), len, max_len);
  62
  63         efx_rx_queue_channel(rx_queue)->n_rx_overlength++;
  64 }
  65
  66 /* Allocate and construct an SKB around page fragments */
  67 static struct sk_buff *efx_rx_mk_skb(struct efx_channel *channel,
  68                                      struct efx_rx_buffer *rx_buf,
  69                                      unsigned int n_frags,
  70                                      u8 *eh, int hdr_len)
  71 {
  72         struct efx_nic *efx = channel->efx;
  73         struct sk_buff *skb;
  74
  75         /* Allocate an SKB to store the headers */
  76         skb = netdev_alloc_skb(efx->net_dev,
  77                                efx->rx_ip_align + efx->rx_prefix_size +
  78                                hdr_len);
  79         if (unlikely(skb == NULL)) {
  80                 atomic_inc(&efx->n_rx_noskb_drops);
  81                 return NULL;
  82         }
  83
  84         EFX_WARN_ON_ONCE_PARANOID(rx_buf->len < hdr_len);
  85
  86         memcpy(skb->data + efx->rx_ip_align, eh - efx->rx_prefix_size,
  87                efx->rx_prefix_size + hdr_len);
  88         skb_reserve(skb, efx->rx_ip_align + efx->rx_prefix_size);
  89         __skb_put(skb, hdr_len);
  90
  91         /* Append the remaining page(s) onto the frag list */
  92         if (rx_buf->len > hdr_len) {
  93                 rx_buf->page_offset += hdr_len;
  94                 rx_buf->len -= hdr_len;
  95
  96                 for (;;) {
  97                         skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
  98                                         rx_buf->page, rx_buf->page_offset,
  99                                         rx_buf->len, efx->rx_buffer_truesize);
 100                         rx_buf->page = NULL;
 101
 102                         if (skb_shinfo(skb)->nr_frags == n_frags)
 103                                 break;
 104
 105                         rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
 106                 }
 107         } else {
 108                 __free_pages(rx_buf->page, efx->rx_buffer_order);
 109                 rx_buf->page = NULL;
 110                 n_frags = 0;
 111         }
 112
 113         /* Move past the ethernet header */
 114         skb->protocol = eth_type_trans(skb, efx->net_dev);
 115
 116         skb_mark_napi_id(skb, &channel->napi_str);
 117
 118         return skb;
 119 }
 120
 121 void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
 122                    unsigned int n_frags, unsigned int len, u16 flags)
 123 {
 124         struct efx_nic *efx = rx_queue->efx;
 125         struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
 126         struct efx_rx_buffer *rx_buf;
 127
 128         rx_queue->rx_packets++;
 129
 130         rx_buf = efx_rx_buffer(rx_queue, index);
 131         rx_buf->flags |= flags;
 132
 133         /* Validate the number of fragments and completed length */
 134         if (n_frags == 1) {
 135                 if (!(flags & EFX_RX_PKT_PREFIX_LEN))
 136                         efx_rx_packet__check_len(rx_queue, rx_buf, len);
 137         } else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
 138                    unlikely(len <= (n_frags - 1) * efx->rx_dma_len) ||
 139                    unlikely(len > n_frags * efx->rx_dma_len) ||
 140                    unlikely(!efx->rx_scatter)) {
 141                 /* If this isn't an explicit discard request, either
 142                  * the hardware or the driver is broken.
 143                  */
 144                 WARN_ON(!(len == 0 && rx_buf->flags & EFX_RX_PKT_DISCARD));
 145                 rx_buf->flags |= EFX_RX_PKT_DISCARD;
 146         }
 147
 148         netif_vdbg(efx, rx_status, efx->net_dev,
 149                    "RX queue %d received ids %x-%x len %d %s%s\n",
 150                    efx_rx_queue_index(rx_queue), index,
 151                    (index + n_frags - 1) & rx_queue->ptr_mask, len,
 152                    (rx_buf->flags & EFX_RX_PKT_CSUMMED) ? " [SUMMED]" : "",
 153                    (rx_buf->flags & EFX_RX_PKT_DISCARD) ? " [DISCARD]" : "");
 154
 155         /* Discard packet, if instructed to do so.  Process the
 156          * previous receive first.
 157          */
 158         if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
 159                 efx_rx_flush_packet(channel);
 160                 efx_discard_rx_packet(channel, rx_buf, n_frags);
 161                 return;
 162         }
 163
 164         if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
 165                 rx_buf->len = len;
 166
 167         /* Release and/or sync the DMA mapping - assumes all RX buffers
 168          * consumed in-order per RX queue.
 169          */
 170         efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
 171
 172         /* Prefetch nice and early so data will (hopefully) be in cache by
 173          * the time we look at it.
 174          */
 175         prefetch(efx_rx_buf_va(rx_buf));
 176
 177         rx_buf->page_offset += efx->rx_prefix_size;
 178         rx_buf->len -= efx->rx_prefix_size;
 179
 180         if (n_frags > 1) {
 181                 /* Release/sync DMA mapping for additional fragments.
 182                  * Fix length for last fragment.
 183                  */
 184                 unsigned int tail_frags = n_frags - 1;
 185
 186                 for (;;) {
 187                         rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
 188                         if (--tail_frags == 0)
 189                                 break;
 190                         efx_sync_rx_buffer(efx, rx_buf, efx->rx_dma_len);
 191                 }
 192                 rx_buf->len = len - (n_frags - 1) * efx->rx_dma_len;
 193                 efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
 194         }
 195
 196         /* All fragments have been DMA-synced, so recycle pages. */
 197         rx_buf = efx_rx_buffer(rx_queue, index);
 198         efx_recycle_rx_pages(channel, rx_buf, n_frags);
 199
 200         /* Pipeline receives so that we give time for packet headers to be
 201          * prefetched into cache.
 202          */
 203         efx_rx_flush_packet(channel);
 204         channel->rx_pkt_n_frags = n_frags;
 205         channel->rx_pkt_index = index;
 206 }
 207
 208 static void efx_rx_deliver(struct efx_channel *channel, u8 *eh,
 209                            struct efx_rx_buffer *rx_buf,
 210                            unsigned int n_frags)
 211 {
 212         struct sk_buff *skb;
 213         u16 hdr_len = min_t(u16, rx_buf->len, EFX_SKB_HEADERS);
 214
 215         skb = efx_rx_mk_skb(channel, rx_buf, n_frags, eh, hdr_len);
 216         if (unlikely(skb == NULL)) {
 217                 struct efx_rx_queue *rx_queue;
 218
 219                 rx_queue = efx_channel_get_rx_queue(channel);
 220                 efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
 221                 return;
 222         }
 223         skb_record_rx_queue(skb, channel->rx_queue.core_index);
 224
 225         /* Set the SKB flags */
 226         skb_checksum_none_assert(skb);
 227         if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED)) {
 228                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 229                 skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
 230         }
 231
 232         efx_rx_skb_attach_timestamp(channel, skb);
 233
 234         if (channel->type->receive_skb)
 235                 if (channel->type->receive_skb(channel, skb))
 236                         return;
 237
 238         /* Pass the packet up */
 239         if (channel->rx_list != NULL)
 240                 /* Add to list, will pass up later */
 241                 list_add_tail(&skb->list, channel->rx_list);
 242         else
 243                 /* No list, so pass it up now */
 244                 netif_receive_skb(skb);
 245 }
 246
 247 /** efx_do_xdp: perform XDP processing on a received packet
 248  *
 249  * Returns true if packet should still be delivered.
 250  */
 251 static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
 252                        struct efx_rx_buffer *rx_buf, u8 **ehp)
 253 {
 254         u8 rx_prefix[EFX_MAX_RX_PREFIX_SIZE];
 255         struct efx_rx_queue *rx_queue;
 256         struct bpf_prog *xdp_prog;
 257         struct xdp_frame *xdpf;
 258         struct xdp_buff xdp;
 259         u32 xdp_act;
 260         s16 offset;
 261         int err;
 262
 263         xdp_prog = rcu_dereference_bh(efx->xdp_prog);
 264         if (!xdp_prog)
 265                 return true;
 266
 267         rx_queue = efx_channel_get_rx_queue(channel);
 268
 269         if (unlikely(channel->rx_pkt_n_frags > 1)) {
 270                 /* We can't do XDP on fragmented packets - drop. */
 271                 efx_free_rx_buffers(rx_queue, rx_buf,
 272                                     channel->rx_pkt_n_frags);
 273                 if (net_ratelimit())
 274                         netif_err(efx, rx_err, efx->net_dev,
 275                                   "XDP is not possible with multiple receive fragments (%d)\n",
 276                                   channel->rx_pkt_n_frags);
 277                 channel->n_rx_xdp_bad_drops++;
 278                 return false;
 279         }
 280
 281         dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr,
 282                                 rx_buf->len, DMA_FROM_DEVICE);
 283
 284         /* Save the rx prefix. */
 285         EFX_WARN_ON_PARANOID(efx->rx_prefix_size > EFX_MAX_RX_PREFIX_SIZE);
 286         memcpy(rx_prefix, *ehp - efx->rx_prefix_size,
 287                efx->rx_prefix_size);
 288
 289         xdp_init_buff(&xdp, efx->rx_page_buf_step, &rx_queue->xdp_rxq_info);
 290         /* No support yet for XDP metadata */
 291         xdp_prepare_buff(&xdp, *ehp - EFX_XDP_HEADROOM, EFX_XDP_HEADROOM,
 292                          rx_buf->len, false);
 293
 294         xdp_act = bpf_prog_run_xdp(xdp_prog, &xdp);
 295
 296         offset = (u8 *)xdp.data - *ehp;
 297
 298         switch (xdp_act) {
 299         case XDP_PASS:
 300                 /* Fix up rx prefix. */
 301                 if (offset) {
 302                         *ehp += offset;
 303                         rx_buf->page_offset += offset;
 304                         rx_buf->len -= offset;
 305                         memcpy(*ehp - efx->rx_prefix_size, rx_prefix,
 306                                efx->rx_prefix_size);
 307                 }
 308                 break;
 309
 310         case XDP_TX:
 311                 /* Buffer ownership passes to tx on success. */
 312                 xdpf = xdp_convert_buff_to_frame(&xdp);
 313                 err = efx_xdp_tx_buffers(efx, 1, &xdpf, true);
 314                 if (unlikely(err != 1)) {
 315                         efx_free_rx_buffers(rx_queue, rx_buf, 1);
 316                         if (net_ratelimit())
 317                                 netif_err(efx, rx_err, efx->net_dev,
 318                                           "XDP TX failed (%d)\n", err);
 319                         channel->n_rx_xdp_bad_drops++;
 320                         trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 321                 } else {
 322                         channel->n_rx_xdp_tx++;
 323                 }
 324                 break;
 325
 326         case XDP_REDIRECT:
 327                 err = xdp_do_redirect(efx->net_dev, &xdp, xdp_prog);
 328                 if (unlikely(err)) {
 329                         efx_free_rx_buffers(rx_queue, rx_buf, 1);
 330                         if (net_ratelimit())
 331                                 netif_err(efx, rx_err, efx->net_dev,
 332                                           "XDP redirect failed (%d)\n", err);
 333                         channel->n_rx_xdp_bad_drops++;
 334                         trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 335                 } else {
 336                         channel->n_rx_xdp_redirect++;
 337                 }
 338                 break;
 339
 340         default:
 341                 bpf_warn_invalid_xdp_action(efx->net_dev, xdp_prog, xdp_act);
 342                 efx_free_rx_buffers(rx_queue, rx_buf, 1);
 343                 channel->n_rx_xdp_bad_drops++;
 344                 trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 345                 break;
 346
 347         case XDP_ABORTED:
 348                 trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 349                 fallthrough;
 350         case XDP_DROP:
 351                 efx_free_rx_buffers(rx_queue, rx_buf, 1);
 352                 channel->n_rx_xdp_drops++;
 353                 break;
 354         }
 355
 356         return xdp_act == XDP_PASS;
 357 }
 358
 359 /* Handle a received packet.  Second half: Touches packet payload. */
 360 void __efx_rx_packet(struct efx_channel *channel)
 361 {
 362         struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
 363         struct efx_nic *efx = channel->efx;
 364         struct efx_rx_buffer *rx_buf =
 365                 efx_rx_buffer(rx_queue, channel->rx_pkt_index);
 366         u8 *eh = efx_rx_buf_va(rx_buf);
 367
 368         /* Read length from the prefix if necessary.  This already
 369          * excludes the length of the prefix itself.
 370          */
 371         if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN) {
 372                 rx_buf->len = le16_to_cpup((__le16 *)
 373                                            (eh + efx->rx_packet_len_offset));
 374                 /* A known issue may prevent this being filled in;
 375                  * if that happens, just drop the packet.
 376                  * Must do that in the driver since passing a zero-length
 377                  * packet up to the stack may cause a crash.
 378                  */
 379                 if (unlikely(!rx_buf->len)) {
 380                         efx_free_rx_buffers(rx_queue, rx_buf,
 381                                             channel->rx_pkt_n_frags);
 382                         channel->n_rx_frm_trunc++;
 383                         goto out;
 384                 }
 385         }
 386
 387         /* If we're in loopback test, then pass the packet directly to the
 388          * loopback layer, and free the rx_buf here
 389          */
 390         if (unlikely(efx->loopback_selftest)) {
 391                 efx_loopback_rx_packet(efx, eh, rx_buf->len);
 392                 efx_free_rx_buffers(rx_queue, rx_buf,
 393                                     channel->rx_pkt_n_frags);
 394                 goto out;
 395         }
 396
 397         if (!efx_do_xdp(efx, channel, rx_buf, &eh))
 398                 goto out;
 399
 400         if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
 401                 rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
 402
 403         if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
 404                 efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh, 0);
 405         else
 406                 efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);
 407 out:
 408         channel->rx_pkt_n_frags = 0;
 409 }