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_buf = efx_rx_buffer(rx_queue, index);
 129         rx_buf->flags |= flags;
 130
 131         /* Validate the number of fragments and completed length */
 132         if (n_frags == 1) {
 133                 if (!(flags & EFX_RX_PKT_PREFIX_LEN))
 134                         efx_rx_packet__check_len(rx_queue, rx_buf, len);
 135         } else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
 136                    unlikely(len <= (n_frags - 1) * efx->rx_dma_len) ||
 137                    unlikely(len > n_frags * efx->rx_dma_len) ||
 138                    unlikely(!efx->rx_scatter)) {
 139                 /* If this isn't an explicit discard request, either
 140                  * the hardware or the driver is broken.
 141                  */
 142                 WARN_ON(!(len == 0 && rx_buf->flags & EFX_RX_PKT_DISCARD));
 143                 rx_buf->flags |= EFX_RX_PKT_DISCARD;
 144         }
 145
 146         netif_vdbg(efx, rx_status, efx->net_dev,
 147                    "RX queue %d received ids %x-%x len %d %s%s\n",
 148                    efx_rx_queue_index(rx_queue), index,
 149                    (index + n_frags - 1) & rx_queue->ptr_mask, len,
 150                    (rx_buf->flags & EFX_RX_PKT_CSUMMED) ? " [SUMMED]" : "",
 151                    (rx_buf->flags & EFX_RX_PKT_DISCARD) ? " [DISCARD]" : "");
 152
 153         /* Discard packet, if instructed to do so.  Process the
 154          * previous receive first.
 155          */
 156         if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
 157                 efx_rx_flush_packet(channel);
 158                 efx_discard_rx_packet(channel, rx_buf, n_frags);
 159                 return;
 160         }
 161
 162         if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
 163                 rx_buf->len = len;
 164
 165         /* Release and/or sync the DMA mapping - assumes all RX buffers
 166          * consumed in-order per RX queue.
 167          */
 168         efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
 169
 170         /* Prefetch nice and early so data will (hopefully) be in cache by
 171          * the time we look at it.
 172          */
 173         prefetch(efx_rx_buf_va(rx_buf));
 174
 175         rx_buf->page_offset += efx->rx_prefix_size;
 176         rx_buf->len -= efx->rx_prefix_size;
 177
 178         if (n_frags > 1) {
 179                 /* Release/sync DMA mapping for additional fragments.
 180                  * Fix length for last fragment.
 181                  */
 182                 unsigned int tail_frags = n_frags - 1;
 183
 184                 for (;;) {
 185                         rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
 186                         if (--tail_frags == 0)
 187                                 break;
 188                         efx_sync_rx_buffer(efx, rx_buf, efx->rx_dma_len);
 189                 }
 190                 rx_buf->len = len - (n_frags - 1) * efx->rx_dma_len;
 191                 efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
 192         }
 193
 194         /* All fragments have been DMA-synced, so recycle pages. */
 195         rx_buf = efx_rx_buffer(rx_queue, index);
 196         efx_recycle_rx_pages(channel, rx_buf, n_frags);
 197
 198         /* Pipeline receives so that we give time for packet headers to be
 199          * prefetched into cache.
 200          */
 201         efx_rx_flush_packet(channel);
 202         channel->rx_pkt_n_frags = n_frags;
 203         channel->rx_pkt_index = index;
 204 }
 205
 206 static void efx_rx_deliver(struct efx_channel *channel, u8 *eh,
 207                            struct efx_rx_buffer *rx_buf,
 208                            unsigned int n_frags)
 209 {
 210         struct sk_buff *skb;
 211         u16 hdr_len = min_t(u16, rx_buf->len, EFX_SKB_HEADERS);
 212
 213         skb = efx_rx_mk_skb(channel, rx_buf, n_frags, eh, hdr_len);
 214         if (unlikely(skb == NULL)) {
 215                 struct efx_rx_queue *rx_queue;
 216
 217                 rx_queue = efx_channel_get_rx_queue(channel);
 218                 efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
 219                 return;
 220         }
 221         skb_record_rx_queue(skb, channel->rx_queue.core_index);
 222
 223         /* Set the SKB flags */
 224         skb_checksum_none_assert(skb);
 225         if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED)) {
 226                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 227                 skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
 228         }
 229
 230         efx_rx_skb_attach_timestamp(channel, skb);
 231
 232         if (channel->type->receive_skb)
 233                 if (channel->type->receive_skb(channel, skb))
 234                         return;
 235
 236         /* Pass the packet up */
 237         if (channel->rx_list != NULL)
 238                 /* Add to list, will pass up later */
 239                 list_add_tail(&skb->list, channel->rx_list);
 240         else
 241                 /* No list, so pass it up now */
 242                 netif_receive_skb(skb);
 243 }
 244
 245 /** efx_do_xdp: perform XDP processing on a received packet
 246  *
 247  * Returns true if packet should still be delivered.
 248  */
 249 static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
 250                        struct efx_rx_buffer *rx_buf, u8 **ehp)
 251 {
 252         u8 rx_prefix[EFX_MAX_RX_PREFIX_SIZE];
 253         struct efx_rx_queue *rx_queue;
 254         struct bpf_prog *xdp_prog;
 255         struct xdp_frame *xdpf;
 256         struct xdp_buff xdp;
 257         u32 xdp_act;
 258         s16 offset;
 259         int err;
 260
 261         xdp_prog = rcu_dereference_bh(efx->xdp_prog);
 262         if (!xdp_prog)
 263                 return true;
 264
 265         rx_queue = efx_channel_get_rx_queue(channel);
 266
 267         if (unlikely(channel->rx_pkt_n_frags > 1)) {
 268                 /* We can't do XDP on fragmented packets - drop. */
 269                 efx_free_rx_buffers(rx_queue, rx_buf,
 270                                     channel->rx_pkt_n_frags);
 271                 if (net_ratelimit())
 272                         netif_err(efx, rx_err, efx->net_dev,
 273                                   "XDP is not possible with multiple receive fragments (%d)\n",
 274                                   channel->rx_pkt_n_frags);
 275                 channel->n_rx_xdp_bad_drops++;
 276                 return false;
 277         }
 278
 279         dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr,
 280                                 rx_buf->len, DMA_FROM_DEVICE);
 281
 282         /* Save the rx prefix. */
 283         EFX_WARN_ON_PARANOID(efx->rx_prefix_size > EFX_MAX_RX_PREFIX_SIZE);
 284         memcpy(rx_prefix, *ehp - efx->rx_prefix_size,
 285                efx->rx_prefix_size);
 286
 287         xdp_init_buff(&xdp, efx->rx_page_buf_step, &rx_queue->xdp_rxq_info);
 288         /* No support yet for XDP metadata */
 289         xdp_prepare_buff(&xdp, *ehp - EFX_XDP_HEADROOM, EFX_XDP_HEADROOM,
 290                          rx_buf->len, false);
 291
 292         xdp_act = bpf_prog_run_xdp(xdp_prog, &xdp);
 293
 294         offset = (u8 *)xdp.data - *ehp;
 295
 296         switch (xdp_act) {
 297         case XDP_PASS:
 298                 /* Fix up rx prefix. */
 299                 if (offset) {
 300                         *ehp += offset;
 301                         rx_buf->page_offset += offset;
 302                         rx_buf->len -= offset;
 303                         memcpy(*ehp - efx->rx_prefix_size, rx_prefix,
 304                                efx->rx_prefix_size);
 305                 }
 306                 break;
 307
 308         case XDP_TX:
 309                 /* Buffer ownership passes to tx on success. */
 310                 xdpf = xdp_convert_buff_to_frame(&xdp);
 311                 err = efx_xdp_tx_buffers(efx, 1, &xdpf, true);
 312                 if (unlikely(err != 1)) {
 313                         efx_free_rx_buffers(rx_queue, rx_buf, 1);
 314                         if (net_ratelimit())
 315                                 netif_err(efx, rx_err, efx->net_dev,
 316                                           "XDP TX failed (%d)\n", err);
 317                         channel->n_rx_xdp_bad_drops++;
 318                         trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 319                 } else {
 320                         channel->n_rx_xdp_tx++;
 321                 }
 322                 break;
 323
 324         case XDP_REDIRECT:
 325                 err = xdp_do_redirect(efx->net_dev, &xdp, xdp_prog);
 326                 if (unlikely(err)) {
 327                         efx_free_rx_buffers(rx_queue, rx_buf, 1);
 328                         if (net_ratelimit())
 329                                 netif_err(efx, rx_err, efx->net_dev,
 330                                           "XDP redirect failed (%d)\n", err);
 331                         channel->n_rx_xdp_bad_drops++;
 332                         trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 333                 } else {
 334                         channel->n_rx_xdp_redirect++;
 335                 }
 336                 break;
 337
 338         default:
 339                 bpf_warn_invalid_xdp_action(efx->net_dev, xdp_prog, xdp_act);
 340                 efx_free_rx_buffers(rx_queue, rx_buf, 1);
 341                 channel->n_rx_xdp_bad_drops++;
 342                 trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 343                 break;
 344
 345         case XDP_ABORTED:
 346                 trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 347                 fallthrough;
 348         case XDP_DROP:
 349                 efx_free_rx_buffers(rx_queue, rx_buf, 1);
 350                 channel->n_rx_xdp_drops++;
 351                 break;
 352         }
 353
 354         return xdp_act == XDP_PASS;
 355 }
 356
 357 /* Handle a received packet.  Second half: Touches packet payload. */
 358 void __efx_rx_packet(struct efx_channel *channel)
 359 {
 360         struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
 361         struct efx_nic *efx = channel->efx;
 362         struct efx_rx_buffer *rx_buf =
 363                 efx_rx_buffer(rx_queue, channel->rx_pkt_index);
 364         u8 *eh = efx_rx_buf_va(rx_buf);
 365
 366         /* Read length from the prefix if necessary.  This already
 367          * excludes the length of the prefix itself.
 368          */
 369         if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN) {
 370                 rx_buf->len = le16_to_cpup((__le16 *)
 371                                            (eh + efx->rx_packet_len_offset));
 372                 /* A known issue may prevent this being filled in;
 373                  * if that happens, just drop the packet.
 374                  * Must do that in the driver since passing a zero-length
 375                  * packet up to the stack may cause a crash.
 376                  */
 377                 if (unlikely(!rx_buf->len)) {
 378                         efx_free_rx_buffers(rx_queue, rx_buf,
 379                                             channel->rx_pkt_n_frags);
 380                         channel->n_rx_frm_trunc++;
 381                         goto out;
 382                 }
 383         }
 384
 385         /* If we're in loopback test, then pass the packet directly to the
 386          * loopback layer, and free the rx_buf here
 387          */
 388         if (unlikely(efx->loopback_selftest)) {
 389                 efx_loopback_rx_packet(efx, eh, rx_buf->len);
 390                 efx_free_rx_buffers(rx_queue, rx_buf,
 391                                     channel->rx_pkt_n_frags);
 392                 goto out;
 393         }
 394
 395         rx_queue->rx_packets++;
 396         rx_queue->rx_bytes += rx_buf->len;
 397
 398         if (!efx_do_xdp(efx, channel, rx_buf, &eh))
 399                 goto out;
 400
 401         if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
 402                 rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
 403
 404         if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
 405                 efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh, 0);
 406         else
 407                 efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);
 408 out:
 409         channel->rx_pkt_n_frags = 0;
 410 }