output.c

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/*
 *------------------------------------------------------------------
 * Copyright (c) 2018 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *------------------------------------------------------------------
 */

#include <vlib/vlib.h>
#include <vlib/unix/unix.h>
#include <vlib/pci/pci.h>
#include <vppinfra/ring.h>

#include <vnet/ethernet/ethernet.h>
#include <vnet/ip/ip4_packet.h>
#include <vnet/ip/ip6_packet.h>
#include <vnet/udp/udp_packet.h>
#include <vnet/tcp/tcp_packet.h>

#include <vnet/devices/devices.h>

#include <avf/avf.h>

static_always_inline u8
avf_tx_desc_get_dtyp (avf_tx_desc_t * d)
{
  return d->qword[1] & 0x0f;
}

struct avf_ip4_psh
{
  u32 src;
  u32 dst;
  u8 zero;
  u8 proto;
  u16 l4len;
};

struct avf_ip6_psh
{
  ip6_address_t src;
  ip6_address_t dst;
  u32 l4len;
  u32 proto;
};

static_always_inline u64
avf_tx_prepare_cksum (vlib_buffer_t * b, u8 is_tso)
{
  u64 flags = 0;
  if (!is_tso && !(b->flags & VNET_BUFFER_F_OFFLOAD))
    return 0;

  vnet_buffer_oflags_t oflags = vnet_buffer (b)->oflags;
  u32 is_tcp = is_tso || oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM;
  u32 is_udp = !is_tso && oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM;

  if (!is_tcp && !is_udp)
    return 0;

  u32 is_ip4 = b->flags & VNET_BUFFER_F_IS_IP4;
  u32 is_ip6 = b->flags & VNET_BUFFER_F_IS_IP6;

  ASSERT (!(is_tcp && is_udp));
  ASSERT (is_ip4 || is_ip6);
  i16 l2_hdr_offset = b->current_data;
  i16 l3_hdr_offset = vnet_buffer (b)->l3_hdr_offset;
  i16 l4_hdr_offset = vnet_buffer (b)->l4_hdr_offset;
  u16 l2_len = l3_hdr_offset - l2_hdr_offset;
  u16 l3_len = l4_hdr_offset - l3_hdr_offset;
  ip4_header_t *ip4 = (void *) (b->data + l3_hdr_offset);
  ip6_header_t *ip6 = (void *) (b->data + l3_hdr_offset);
  tcp_header_t *tcp = (void *) (b->data + l4_hdr_offset);
  udp_header_t *udp = (void *) (b->data + l4_hdr_offset);
  u16 l4_len = is_tcp ? tcp_header_bytes (tcp) : sizeof (udp_header_t);
  u16 sum = 0;

  flags |= AVF_TXD_OFFSET_MACLEN (l2_len) |
    AVF_TXD_OFFSET_IPLEN (l3_len) | AVF_TXD_OFFSET_L4LEN (l4_len);
  flags |= is_ip4 ? AVF_TXD_CMD_IIPT_IPV4 : AVF_TXD_CMD_IIPT_IPV6;
  flags |= is_tcp ? AVF_TXD_CMD_L4T_TCP : AVF_TXD_CMD_L4T_UDP;

  if (is_ip4)
    ip4->checksum = 0;

  if (is_tso)
    {
      if (is_ip4)
        ip4->length = 0;
      else
        ip6->payload_length = 0;
    }

      if (is_ip4)
        {
          struct avf_ip4_psh psh = { 0 };
          psh.src = ip4->src_address.as_u32;
          psh.dst = ip4->dst_address.as_u32;
          psh.proto = ip4->protocol;
          psh.l4len =
            is_tso ? 0 :
            clib_host_to_net_u16 (clib_net_to_host_u16 (ip4->length) -
                                  (l4_hdr_offset - l3_hdr_offset));
          sum = ~ip_csum (&psh, sizeof (psh));
        }
      else
        {
          struct avf_ip6_psh psh = { 0 };
          psh.src = ip6->src_address;
          psh.dst = ip6->dst_address;
          psh.proto = clib_host_to_net_u32 ((u32) ip6->protocol);
          psh.l4len = is_tso ? 0 : ip6->payload_length;
          sum = ~ip_csum (&psh, sizeof (psh));
        }

  /* ip_csum does a byte swap for some reason... */
  sum = clib_net_to_host_u16 (sum);
  if (is_tcp)
    tcp->checksum = sum;
  else
    udp->checksum = sum;
  return flags;
}

static_always_inline u32
avf_tx_fill_ctx_desc (vlib_main_t *vm, avf_txq_t *txq, avf_tx_desc_t *d,
                      vlib_buffer_t *b)
{
  vlib_buffer_t *ctx_ph;
  u32 *bi = txq->ph_bufs;

next:
  ctx_ph = vlib_get_buffer (vm, bi[0]);
  if (PREDICT_FALSE (ctx_ph->ref_count == 255))
    {
      bi++;
      goto next;
    }

  /* Acquire a reference on the placeholder buffer */
  ctx_ph->ref_count++;

  u16 l234hdr_sz = vnet_buffer (b)->l4_hdr_offset - b->current_data +
                   vnet_buffer2 (b)->gso_l4_hdr_sz;
  u16 tlen = vlib_buffer_length_in_chain (vm, b) - l234hdr_sz;
  d[0].qword[0] = 0;
  d[0].qword[1] = AVF_TXD_DTYP_CTX | AVF_TXD_CTX_CMD_TSO
    | AVF_TXD_CTX_SEG_MSS (vnet_buffer2 (b)->gso_size) |
    AVF_TXD_CTX_SEG_TLEN (tlen);
  return bi[0];
}

static_always_inline void
avf_tx_copy_desc (avf_tx_desc_t *d, avf_tx_desc_t *s, u32 n_descs)
{
#if defined CLIB_HAVE_VEC512
  while (n_descs >= 8)
    {
      u64x8u *dv = (u64x8u *) d;
      u64x8u *sv = (u64x8u *) s;

      dv[0] = sv[0];
      dv[1] = sv[1];

      /* next */
      d += 8;
      s += 8;
      n_descs -= 8;
    }
#elif defined CLIB_HAVE_VEC256
  while (n_descs >= 4)
    {
      u64x4u *dv = (u64x4u *) d;
      u64x4u *sv = (u64x4u *) s;

      dv[0] = sv[0];
      dv[1] = sv[1];

      /* next */
      d += 4;
      s += 4;
      n_descs -= 4;
    }
#elif defined CLIB_HAVE_VEC128
  while (n_descs >= 2)
    {
      u64x2u *dv = (u64x2u *) d;
      u64x2u *sv = (u64x2u *) s;

      dv[0] = sv[0];
      dv[1] = sv[1];

      /* next */
      d += 2;
      s += 2;
      n_descs -= 2;
    }
#endif
  while (n_descs)
    {
      d[0].qword[0] = s[0].qword[0];
      d[0].qword[1] = s[0].qword[1];
      d++;
      s++;
      n_descs--;
    }
}

static_always_inline void
avf_tx_fill_data_desc (vlib_main_t *vm, avf_tx_desc_t *d, vlib_buffer_t *b,
                       u64 cmd, int use_va_dma)
{
  if (use_va_dma)
    d->qword[0] = vlib_buffer_get_current_va (b);
  else
    d->qword[0] = vlib_buffer_get_current_pa (vm, b);
  d->qword[1] = (((u64) b->current_length) << 34 | cmd | AVF_TXD_CMD_RSV);
}
static_always_inline u16
avf_tx_prepare (vlib_main_t *vm, vlib_node_runtime_t *node, avf_txq_t *txq,
                u32 *buffers, u32 n_packets, u16 *n_enq_descs, int use_va_dma)
{
  const u64 cmd_eop = AVF_TXD_CMD_EOP;
  u16 n_free_desc, n_desc_left, n_packets_left = n_packets;
  vlib_buffer_t *b[4];
  avf_tx_desc_t *d = txq->tmp_descs;
  u32 *tb = txq->tmp_bufs;

  n_free_desc = n_desc_left = txq->size - txq->n_enqueued - 8;

  if (n_desc_left == 0)
    return 0;

  while (n_packets_left && n_desc_left)
    {
      u32 flags, or_flags;

      if (n_packets_left < 8 || n_desc_left < 4)
        goto one_by_one;

      vlib_prefetch_buffer_with_index (vm, buffers[4], LOAD);
      vlib_prefetch_buffer_with_index (vm, buffers[5], LOAD);
      vlib_prefetch_buffer_with_index (vm, buffers[6], LOAD);
      vlib_prefetch_buffer_with_index (vm, buffers[7], LOAD);

      b[0] = vlib_get_buffer (vm, buffers[0]);
      b[1] = vlib_get_buffer (vm, buffers[1]);
      b[2] = vlib_get_buffer (vm, buffers[2]);
      b[3] = vlib_get_buffer (vm, buffers[3]);

      or_flags = b[0]->flags | b[1]->flags | b[2]->flags | b[3]->flags;

      if (PREDICT_FALSE (or_flags &
                         (VLIB_BUFFER_NEXT_PRESENT | VNET_BUFFER_F_OFFLOAD |
                          VNET_BUFFER_F_GSO)))
        goto one_by_one;

      vlib_buffer_copy_indices (tb, buffers, 4);

      avf_tx_fill_data_desc (vm, d + 0, b[0], cmd_eop, use_va_dma);
      avf_tx_fill_data_desc (vm, d + 1, b[1], cmd_eop, use_va_dma);
      avf_tx_fill_data_desc (vm, d + 2, b[2], cmd_eop, use_va_dma);
      avf_tx_fill_data_desc (vm, d + 3, b[3], cmd_eop, use_va_dma);

      buffers += 4;
      n_packets_left -= 4;
      n_desc_left -= 4;
      d += 4;
      tb += 4;
      continue;

    one_by_one:
      tb[0] = buffers[0];
      b[0] = vlib_get_buffer (vm, buffers[0]);
      flags = b[0]->flags;

      /* No chained buffers or TSO case */
      if (PREDICT_TRUE (
            (flags & (VLIB_BUFFER_NEXT_PRESENT | VNET_BUFFER_F_GSO)) == 0))
        {
          u64 cmd = cmd_eop;

          if (PREDICT_FALSE (flags & VNET_BUFFER_F_OFFLOAD))
            cmd |= avf_tx_prepare_cksum (b[0], 0 /* is_tso */);

          avf_tx_fill_data_desc (vm, d, b[0], cmd, use_va_dma);
        }
      else
        {
          u16 n_desc_needed = 1;
          u64 cmd = 0;

          if (flags & VLIB_BUFFER_NEXT_PRESENT)
            {
              vlib_buffer_t *next = vlib_get_buffer (vm, b[0]->next_buffer);
              n_desc_needed = 2;
              while (next->flags & VLIB_BUFFER_NEXT_PRESENT)
                {
                  next = vlib_get_buffer (vm, next->next_buffer);
                  n_desc_needed++;
                }
            }

          if (flags & VNET_BUFFER_F_GSO)
            {
              n_desc_needed++;
            }
          else if (PREDICT_FALSE (n_desc_needed > 8))
            {
              vlib_buffer_free_one (vm, buffers[0]);
              vlib_error_count (vm, node->node_index,
                                AVF_TX_ERROR_SEGMENT_SIZE_EXCEEDED, 1);
              n_packets_left -= 1;
              buffers += 1;
              continue;
            }

          if (PREDICT_FALSE (n_desc_left < n_desc_needed))
            break;

          if (flags & VNET_BUFFER_F_GSO)
            {
              /* Enqueue a context descriptor */
              tb[1] = tb[0];
              tb[0] = avf_tx_fill_ctx_desc (vm, txq, d, b[0]);
              n_desc_left -= 1;
              d += 1;
              tb += 1;
              cmd = avf_tx_prepare_cksum (b[0], 1 /* is_tso */);
            }
          else if (flags & VNET_BUFFER_F_OFFLOAD)
            {
              cmd = avf_tx_prepare_cksum (b[0], 0 /* is_tso */);
            }

          /* Deal with chain buffer if present */
          while (b[0]->flags & VLIB_BUFFER_NEXT_PRESENT)
            {
              avf_tx_fill_data_desc (vm, d, b[0], cmd, use_va_dma);

              n_desc_left -= 1;
              d += 1;
              tb += 1;

              tb[0] = b[0]->next_buffer;
              b[0] = vlib_get_buffer (vm, b[0]->next_buffer);
            }

          avf_tx_fill_data_desc (vm, d, b[0], cmd_eop | cmd, use_va_dma);
        }

      buffers += 1;
      n_packets_left -= 1;
      n_desc_left -= 1;
      d += 1;
      tb += 1;
    }

  *n_enq_descs = n_free_desc - n_desc_left;
  return n_packets - n_packets_left;
}

VNET_DEVICE_CLASS_TX_FN (avf_device_class) (vlib_main_t * vm,
                                            vlib_node_runtime_t * node,
                                            vlib_frame_t * frame)
{
  vnet_interface_output_runtime_t *rd = (void *) node->runtime_data;
  avf_device_t *ad = avf_get_device (rd->dev_instance);
  vnet_hw_if_tx_frame_t *tf = vlib_frame_scalar_args (frame);
  u8 qid = tf->queue_id;
  avf_txq_t *txq = vec_elt_at_index (ad->txqs, qid);
  u16 next;
  u16 mask = txq->size - 1;
  u32 *buffers = vlib_frame_vector_args (frame);
  u16 n_enq, n_left, n_desc, *slot;
  u16 n_retry = 2;

  if (tf->shared_queue)
    clib_spinlock_lock (&txq->lock);

  n_left = frame->n_vectors;

retry:
  next = txq->next;
  /* release consumed bufs */
  if (txq->n_enqueued)
    {
      i32 complete_slot = -1;
      while (1)
        {
          u16 *slot = clib_ring_get_first (txq->rs_slots);

          if (slot == 0)
            break;

          if (avf_tx_desc_get_dtyp (txq->descs + slot[0]) != 0x0F)
            break;

          complete_slot = slot[0];

          clib_ring_deq (txq->rs_slots);
        }

      if (complete_slot >= 0)
        {
          u16 first, mask, n_free;
          mask = txq->size - 1;
          first = (txq->next - txq->n_enqueued) & mask;
          n_free = (complete_slot + 1 - first) & mask;

          txq->n_enqueued -= n_free;
          vlib_buffer_free_from_ring_no_next (vm, txq->bufs, first, txq->size,
                                              n_free);
        }
    }

  n_desc = 0;
  if (ad->flags & AVF_DEVICE_F_VA_DMA)
    n_enq = avf_tx_prepare (vm, node, txq, buffers, n_left, &n_desc, 1);
  else
    n_enq = avf_tx_prepare (vm, node, txq, buffers, n_left, &n_desc, 0);

  if (n_desc)
    {
      if (PREDICT_TRUE (next + n_desc <= txq->size))
        {
          /* no wrap */
          avf_tx_copy_desc (txq->descs + next, txq->tmp_descs, n_desc);
          vlib_buffer_copy_indices (txq->bufs + next, txq->tmp_bufs, n_desc);
        }
      else
        {
          /* wrap */
          u32 n_not_wrap = txq->size - next;
          avf_tx_copy_desc (txq->descs + next, txq->tmp_descs, n_not_wrap);
          avf_tx_copy_desc (txq->descs, txq->tmp_descs + n_not_wrap,
                            n_desc - n_not_wrap);
          vlib_buffer_copy_indices (txq->bufs + next, txq->tmp_bufs,
                                    n_not_wrap);
          vlib_buffer_copy_indices (txq->bufs, txq->tmp_bufs + n_not_wrap,
                                    n_desc - n_not_wrap);
        }

      next += n_desc;
      if ((slot = clib_ring_enq (txq->rs_slots)))
        {
          u16 rs_slot = slot[0] = (next - 1) & mask;
          txq->descs[rs_slot].qword[1] |= AVF_TXD_CMD_RS;
        }

      txq->next = next & mask;
      avf_tail_write (txq->qtx_tail, txq->next);
      txq->n_enqueued += n_desc;
      n_left -= n_enq;
    }

  if (n_left)
    {
      buffers += n_enq;

      if (n_retry--)
        goto retry;

      vlib_buffer_free (vm, buffers, n_left);
      vlib_error_count (vm, node->node_index,
                        AVF_TX_ERROR_NO_FREE_SLOTS, n_left);
    }

  if (tf->shared_queue)
    clib_spinlock_unlock (&txq->lock);

  return frame->n_vectors - n_left;
}

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */