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_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
  98                                            rx_buf->page, rx_buf->page_offset,
  99                                            rx_buf->len);
 100                         rx_buf->page = NULL;
 101                         skb->len += rx_buf->len;
 102                         skb->data_len += rx_buf->len;
 103                         if (skb_shinfo(skb)->nr_frags == n_frags)
 104                                 break;
 105
 106                         rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
 107                 }
 108         } else {
 109                 __free_pages(rx_buf->page, efx->rx_buffer_order);
 110                 rx_buf->page = NULL;
 111                 n_frags = 0;
 112         }
 113
 114         skb->truesize += n_frags * efx->rx_buffer_truesize;
 115
 116         /* Move past the ethernet header */
 117         skb->protocol = eth_type_trans(skb, efx->net_dev);
 118
 119         skb_mark_napi_id(skb, &channel->napi_str);
 120
 121         return skb;
 122 }
 123
 124 void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
 125                    unsigned int n_frags, unsigned int len, u16 flags)
 126 {
 127         struct efx_nic *efx = rx_queue->efx;
 128         struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
 129         struct efx_rx_buffer *rx_buf;
 130
 131         rx_queue->rx_packets++;
 132
 133         rx_buf = efx_rx_buffer(rx_queue, index);
 134         rx_buf->flags |= flags;
 135
 136         /* Validate the number of fragments and completed length */
 137         if (n_frags == 1) {
 138                 if (!(flags & EFX_RX_PKT_PREFIX_LEN))
 139                         efx_rx_packet__check_len(rx_queue, rx_buf, len);
 140         } else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
 141                    unlikely(len <= (n_frags - 1) * efx->rx_dma_len) ||
 142                    unlikely(len > n_frags * efx->rx_dma_len) ||
 143                    unlikely(!efx->rx_scatter)) {
 144                 /* If this isn't an explicit discard request, either
 145                  * the hardware or the driver is broken.
 146                  */
 147                 WARN_ON(!(len == 0 && rx_buf->flags & EFX_RX_PKT_DISCARD));
 148                 rx_buf->flags |= EFX_RX_PKT_DISCARD;
 149         }
 150
 151         netif_vdbg(efx, rx_status, efx->net_dev,
 152                    "RX queue %d received ids %x-%x len %d %s%s\n",
 153                    efx_rx_queue_index(rx_queue), index,
 154                    (index + n_frags - 1) & rx_queue->ptr_mask, len,
 155                    (rx_buf->flags & EFX_RX_PKT_CSUMMED) ? " [SUMMED]" : "",
 156                    (rx_buf->flags & EFX_RX_PKT_DISCARD) ? " [DISCARD]" : "");
 157
 158         /* Discard packet, if instructed to do so.  Process the
 159          * previous receive first.
 160          */
 161         if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
 162                 efx_rx_flush_packet(channel);
 163                 efx_discard_rx_packet(channel, rx_buf, n_frags);
 164                 return;
 165         }
 166
 167         if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
 168                 rx_buf->len = len;
 169
 170         /* Release and/or sync the DMA mapping - assumes all RX buffers
 171          * consumed in-order per RX queue.
 172          */
 173         efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
 174
 175         /* Prefetch nice and early so data will (hopefully) be in cache by
 176          * the time we look at it.
 177          */
 178         prefetch(efx_rx_buf_va(rx_buf));
 179
 180         rx_buf->page_offset += efx->rx_prefix_size;
 181         rx_buf->len -= efx->rx_prefix_size;
 182
 183         if (n_frags > 1) {
 184                 /* Release/sync DMA mapping for additional fragments.
 185                  * Fix length for last fragment.
 186                  */
 187                 unsigned int tail_frags = n_frags - 1;
 188
 189                 for (;;) {
 190                         rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
 191                         if (--tail_frags == 0)
 192                                 break;
 193                         efx_sync_rx_buffer(efx, rx_buf, efx->rx_dma_len);
 194                 }
 195                 rx_buf->len = len - (n_frags - 1) * efx->rx_dma_len;
 196                 efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
 197         }
 198
 199         /* All fragments have been DMA-synced, so recycle pages. */
 200         rx_buf = efx_rx_buffer(rx_queue, index);
 201         efx_recycle_rx_pages(channel, rx_buf, n_frags);
 202
 203         /* Pipeline receives so that we give time for packet headers to be
 204          * prefetched into cache.
 205          */
 206         efx_rx_flush_packet(channel);
 207         channel->rx_pkt_n_frags = n_frags;
 208         channel->rx_pkt_index = index;
 209 }
 210
 211 static void efx_rx_deliver(struct efx_channel *channel, u8 *eh,
 212                            struct efx_rx_buffer *rx_buf,
 213                            unsigned int n_frags)
 214 {
 215         struct sk_buff *skb;
 216         u16 hdr_len = min_t(u16, rx_buf->len, EFX_SKB_HEADERS);
 217
 218         skb = efx_rx_mk_skb(channel, rx_buf, n_frags, eh, hdr_len);
 219         if (unlikely(skb == NULL)) {
 220                 struct efx_rx_queue *rx_queue;
 221
 222                 rx_queue = efx_channel_get_rx_queue(channel);
 223                 efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
 224                 return;
 225         }
 226         skb_record_rx_queue(skb, channel->rx_queue.core_index);
 227
 228         /* Set the SKB flags */
 229         skb_checksum_none_assert(skb);
 230         if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED)) {
 231                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 232                 skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
 233         }
 234
 235         efx_rx_skb_attach_timestamp(channel, skb);
 236
 237         if (channel->type->receive_skb)
 238                 if (channel->type->receive_skb(channel, skb))
 239                         return;
 240
 241         /* Pass the packet up */
 242         if (channel->rx_list != NULL)
 243                 /* Add to list, will pass up later */
 244                 list_add_tail(&skb->list, channel->rx_list);
 245         else
 246                 /* No list, so pass it up now */
 247                 netif_receive_skb(skb);
 248 }
 249
 250 /** efx_do_xdp: perform XDP processing on a received packet
 251  *
 252  * Returns true if packet should still be delivered.
 253  */
 254 static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
 255                        struct efx_rx_buffer *rx_buf, u8 **ehp)
 256 {
 257         u8 rx_prefix[EFX_MAX_RX_PREFIX_SIZE];
 258         struct efx_rx_queue *rx_queue;
 259         struct bpf_prog *xdp_prog;
 260         struct xdp_frame *xdpf;
 261         struct xdp_buff xdp;
 262         u32 xdp_act;
 263         s16 offset;
 264         int err;
 265
 266         rcu_read_lock();
 267         xdp_prog = rcu_dereference(efx->xdp_prog);
 268         if (!xdp_prog) {
 269                 rcu_read_unlock();
 270                 return true;
 271         }
 272
 273         rx_queue = efx_channel_get_rx_queue(channel);
 274
 275         if (unlikely(channel->rx_pkt_n_frags > 1)) {
 276                 /* We can't do XDP on fragmented packets - drop. */
 277                 rcu_read_unlock();
 278                 efx_free_rx_buffers(rx_queue, rx_buf,
 279                                     channel->rx_pkt_n_frags);
 280                 if (net_ratelimit())
 281                         netif_err(efx, rx_err, efx->net_dev,
 282                                   "XDP is not possible with multiple receive fragments (%d)\n",
 283                                   channel->rx_pkt_n_frags);
 284                 channel->n_rx_xdp_bad_drops++;
 285                 return false;
 286         }
 287
 288         dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr,
 289                                 rx_buf->len, DMA_FROM_DEVICE);
 290
 291         /* Save the rx prefix. */
 292         EFX_WARN_ON_PARANOID(efx->rx_prefix_size > EFX_MAX_RX_PREFIX_SIZE);
 293         memcpy(rx_prefix, *ehp - efx->rx_prefix_size,
 294                efx->rx_prefix_size);
 295
 296         xdp_init_buff(&xdp, efx->rx_page_buf_step, &rx_queue->xdp_rxq_info);
 297         /* No support yet for XDP metadata */
 298         xdp_prepare_buff(&xdp, *ehp - EFX_XDP_HEADROOM, EFX_XDP_HEADROOM,
 299                          rx_buf->len, false);
 300
 301         xdp_act = bpf_prog_run_xdp(xdp_prog, &xdp);
 302         rcu_read_unlock();
 303
 304         offset = (u8 *)xdp.data - *ehp;
 305
 306         switch (xdp_act) {
 307         case XDP_PASS:
 308                 /* Fix up rx prefix. */
 309                 if (offset) {
 310                         *ehp += offset;
 311                         rx_buf->page_offset += offset;
 312                         rx_buf->len -= offset;
 313                         memcpy(*ehp - efx->rx_prefix_size, rx_prefix,
 314                                efx->rx_prefix_size);
 315                 }
 316                 break;
 317
 318         case XDP_TX:
 319                 /* Buffer ownership passes to tx on success. */
 320                 xdpf = xdp_convert_buff_to_frame(&xdp);
 321                 err = efx_xdp_tx_buffers(efx, 1, &xdpf, true);
 322                 if (unlikely(err != 1)) {
 323                         efx_free_rx_buffers(rx_queue, rx_buf, 1);
 324                         if (net_ratelimit())
 325                                 netif_err(efx, rx_err, efx->net_dev,
 326                                           "XDP TX failed (%d)\n", err);
 327                         channel->n_rx_xdp_bad_drops++;
 328                         trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 329                 } else {
 330                         channel->n_rx_xdp_tx++;
 331                 }
 332                 break;
 333
 334         case XDP_REDIRECT:
 335                 err = xdp_do_redirect(efx->net_dev, &xdp, xdp_prog);
 336                 if (unlikely(err)) {
 337                         efx_free_rx_buffers(rx_queue, rx_buf, 1);
 338                         if (net_ratelimit())
 339                                 netif_err(efx, rx_err, efx->net_dev,
 340                                           "XDP redirect failed (%d)\n", err);
 341                         channel->n_rx_xdp_bad_drops++;
 342                         trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 343                 } else {
 344                         channel->n_rx_xdp_redirect++;
 345                 }
 346                 break;
 347
 348         default:
 349                 bpf_warn_invalid_xdp_action(xdp_act);
 350                 efx_free_rx_buffers(rx_queue, rx_buf, 1);
 351                 channel->n_rx_xdp_bad_drops++;
 352                 trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 353                 break;
 354
 355         case XDP_ABORTED:
 356                 trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
 357                 fallthrough;
 358         case XDP_DROP:
 359                 efx_free_rx_buffers(rx_queue, rx_buf, 1);
 360                 channel->n_rx_xdp_drops++;
 361                 break;
 362         }
 363
 364         return xdp_act == XDP_PASS;
 365 }
 366
 367 /* Handle a received packet.  Second half: Touches packet payload. */
 368 void __efx_rx_packet(struct efx_channel *channel)
 369 {
 370         struct efx_nic *efx = channel->efx;
 371         struct efx_rx_buffer *rx_buf =
 372                 efx_rx_buffer(&channel->rx_queue, channel->rx_pkt_index);
 373         u8 *eh = efx_rx_buf_va(rx_buf);
 374
 375         /* Read length from the prefix if necessary.  This already
 376          * excludes the length of the prefix itself.
 377          */
 378         if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN)
 379                 rx_buf->len = le16_to_cpup((__le16 *)
 380                                            (eh + efx->rx_packet_len_offset));
 381
 382         /* If we're in loopback test, then pass the packet directly to the
 383          * loopback layer, and free the rx_buf here
 384          */
 385         if (unlikely(efx->loopback_selftest)) {
 386                 struct efx_rx_queue *rx_queue;
 387
 388                 efx_loopback_rx_packet(efx, eh, rx_buf->len);
 389                 rx_queue = efx_channel_get_rx_queue(channel);
 390                 efx_free_rx_buffers(rx_queue, rx_buf,
 391                                     channel->rx_pkt_n_frags);
 392                 goto out;
 393         }
 394
 395         if (!efx_do_xdp(efx, channel, rx_buf, &eh))
 396                 goto out;
 397
 398         if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
 399                 rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
 400
 401         if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
 402                 efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh, 0);
 403         else
 404                 efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);
 405 out:
 406         channel->rx_pkt_n_frags = 0;
 407 }