node.c

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/*
 *------------------------------------------------------------------
 * Copyright (c) 2016 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 <vnet/ethernet/ethernet.h>

#include <vnet/devices/netmap/netmap.h>

#define foreach_netmap_input_error

typedef enum {
#define _(f,s) NETMAP_INPUT_ERROR_##f,
  foreach_netmap_input_error
#undef _
  NETMAP_INPUT_N_ERROR,
} netmap_input_error_t;

static char * netmap_input_error_strings[] = {
#define _(n,s) s,
    foreach_netmap_input_error
#undef _
};

enum {
  NETMAP_INPUT_NEXT_DROP,
  NETMAP_INPUT_NEXT_ETHERNET_INPUT,
  NETMAP_INPUT_N_NEXT,
};

typedef struct {
  u32 next_index;
  u32 hw_if_index;
  struct netmap_slot slot;
} netmap_input_trace_t;

static u8 * format_netmap_input_trace (u8 * s, va_list * args)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  netmap_input_trace_t * t = va_arg (*args, netmap_input_trace_t *);
  uword indent = format_get_indent (s);

  s = format (s, "netmap: hw_if_index %d next-index %d",
              t->hw_if_index, t->next_index);
  s = format (s, "\n%Uslot: flags 0x%x len %u buf_idx %u",
              format_white_space, indent + 2,
              t->slot.flags, t->slot.len, t->slot.buf_idx);
  return s;
}

always_inline void
buffer_add_to_chain(vlib_main_t *vm, u32 bi, u32 first_bi, u32 prev_bi)
{
  vlib_buffer_t * b = vlib_get_buffer (vm, bi);
  vlib_buffer_t * first_b = vlib_get_buffer (vm, first_bi);
  vlib_buffer_t * prev_b = vlib_get_buffer (vm, prev_bi);

  /* update first buffer */
  first_b->total_length_not_including_first_buffer +=  b->current_length;

  /* update previous buffer */
  prev_b->next_buffer = bi;
  prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;

  /* update current buffer */
  b->next_buffer = 0;

#if DPDK > 0
  struct rte_mbuf * mbuf = rte_mbuf_from_vlib_buffer(b);
  struct rte_mbuf * first_mbuf = rte_mbuf_from_vlib_buffer(first_b);
  struct rte_mbuf * prev_mbuf = rte_mbuf_from_vlib_buffer(prev_b);
  first_mbuf->nb_segs++;
  prev_mbuf->next = mbuf;
  mbuf->data_len = b->current_length;
  mbuf->data_off = RTE_PKTMBUF_HEADROOM + b->current_data;
  mbuf->next = 0;
#endif
}

always_inline uword
netmap_device_input_fn  (vlib_main_t * vm, vlib_node_runtime_t * node,
                            vlib_frame_t * frame, u32 device_idx)
{
  u32 next_index = NETMAP_INPUT_NEXT_ETHERNET_INPUT;
  uword n_trace = vlib_get_trace_count (vm, node);
  netmap_main_t * nm = &netmap_main;
  netmap_if_t * nif = pool_elt_at_index(nm->interfaces, device_idx);
  u32 n_rx_packets = 0;
  u32 n_rx_bytes = 0;
  u32 * to_next = 0;
  u32 n_free_bufs;
  struct netmap_ring * ring;
  int cur_ring;
  u32 n_buffer_bytes = vlib_buffer_free_list_buffer_size (vm,
    VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);

  if (nif->per_interface_next_index != ~0)
      next_index = nif->per_interface_next_index;

  n_free_bufs = vec_len (nm->rx_buffers);
  if (PREDICT_FALSE(n_free_bufs < VLIB_FRAME_SIZE))
    {
      vec_validate(nm->rx_buffers, VLIB_FRAME_SIZE + n_free_bufs - 1);
      n_free_bufs += vlib_buffer_alloc(vm, &nm->rx_buffers[n_free_bufs], VLIB_FRAME_SIZE);
      _vec_len (nm->rx_buffers) = n_free_bufs;
    }

  cur_ring = nif->first_rx_ring;
  while (cur_ring <= nif->last_rx_ring && n_free_bufs)
    {
      int r = 0;
      u32 cur_slot_index;
      ring = NETMAP_RXRING(nif->nifp, cur_ring);
      r = nm_ring_space(ring);

      if (!r)
        {
          cur_ring++;
          continue;
        }

      if (r > n_free_bufs)
        r = n_free_bufs;

      cur_slot_index = ring->cur;
      while (r)
        {
          u32 n_left_to_next;
          u32 next0 = next_index;
          vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

          while (r && n_left_to_next)
            {
              vlib_buffer_t * b0, * first_b0 = 0;
              u32 offset = 0;
              u32 bi0 = 0, first_bi0 = 0, prev_bi0;
              u32 next_slot_index = (cur_slot_index + 1) % ring->num_slots;
              u32 next2_slot_index = (cur_slot_index + 2) % ring->num_slots;
              struct netmap_slot * slot = &ring->slot[cur_slot_index];
              u32 data_len = slot->len;

              /* prefetch 2 slots in advance */
              CLIB_PREFETCH (&ring->slot[next2_slot_index], CLIB_CACHE_LINE_BYTES, LOAD);
              /* prefetch start of next packet */
              CLIB_PREFETCH (NETMAP_BUF(ring, ring->slot[next_slot_index].buf_idx),
                             CLIB_CACHE_LINE_BYTES, LOAD);

              while (data_len && n_free_bufs)
                {
                  /* grab free buffer */
                  u32 last_empty_buffer = vec_len (nm->rx_buffers) - 1;
                  prev_bi0 = bi0;
                  bi0 = nm->rx_buffers[last_empty_buffer];
                  b0 = vlib_get_buffer (vm, bi0);
                  _vec_len (nm->rx_buffers) = last_empty_buffer;
                  n_free_bufs--;

                  /* copy data */
                  u32 bytes_to_copy = data_len > n_buffer_bytes ? n_buffer_bytes : data_len;
                  b0->current_data = 0;
                  clib_memcpy (vlib_buffer_get_current (b0),
                          (u8 *) NETMAP_BUF(ring, slot->buf_idx) + offset,
                          bytes_to_copy);

                  /* fill buffer header */
                  b0->clone_count = 0;
                  b0->current_length = bytes_to_copy;

                  if (offset == 0)
                    {
#if DPDK > 0
                      struct rte_mbuf * mb = rte_mbuf_from_vlib_buffer(b0);
                      rte_pktmbuf_data_len (mb) = b0->current_length;
                      rte_pktmbuf_pkt_len (mb) = b0->current_length;
#endif
                      b0->total_length_not_including_first_buffer = 0;
                      b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
                      vnet_buffer(b0)->sw_if_index[VLIB_RX] = nif->sw_if_index;
                      vnet_buffer(b0)->sw_if_index[VLIB_TX] = (u32)~0;
                      first_bi0 = bi0;
                      first_b0 = vlib_get_buffer(vm, first_bi0);
                    }
                  else
                    buffer_add_to_chain(vm, bi0, first_bi0, prev_bi0);

                  offset += bytes_to_copy;
                  data_len -= bytes_to_copy;
                }

              /* trace */
              VLIB_BUFFER_TRACE_TRAJECTORY_INIT(first_b0);
              if (PREDICT_FALSE(n_trace > 0))
                {
                  netmap_input_trace_t *tr;
                  vlib_trace_buffer (vm, node, next0, first_b0, /* follow_chain */ 0);
                  vlib_set_trace_count (vm, node, --n_trace);
                  tr = vlib_add_trace (vm, node, first_b0, sizeof (*tr));
                  tr->next_index = next0;
                  tr->hw_if_index = nif->hw_if_index;
                  memcpy (&tr->slot, slot, sizeof (struct netmap_slot));
                }
              /* enque and take next packet */
              vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
                                               n_left_to_next, first_bi0, next0);

              /* next packet */
              n_rx_packets++;
              n_rx_bytes += slot->len;
              to_next[0] = first_bi0;
              to_next += 1;
              n_left_to_next--;
              cur_slot_index = next_slot_index;

              r--;
            }
          vlib_put_next_frame (vm, node, next_index, n_left_to_next);
        }
       ring->head = ring->cur = cur_slot_index;
       cur_ring++;
    }

  if (n_rx_packets)
    ioctl(nif->fd, NIOCRXSYNC, NULL);

  vlib_increment_combined_counter
    (vnet_get_main()->interface_main.combined_sw_if_counters
     + VNET_INTERFACE_COUNTER_RX,
     os_get_cpu_number(),
     nif->hw_if_index,
     n_rx_packets, n_rx_bytes);

  return n_rx_packets;
}

static uword
netmap_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
                    vlib_frame_t * frame)
{
  int i;
  u32 n_rx_packets = 0;

  netmap_main_t * nm = &netmap_main;

  clib_bitmap_foreach (i, nm->pending_input_bitmap,
    ({
      clib_bitmap_set (nm->pending_input_bitmap, i, 0);
      n_rx_packets += netmap_device_input_fn(vm, node, frame, i);
    }));

  return n_rx_packets;
}


VLIB_REGISTER_NODE (netmap_input_node) = {
  .function = netmap_input_fn,
  .name = "netmap-input",
  .format_trace = format_netmap_input_trace,
  .type = VLIB_NODE_TYPE_INPUT,
  .state = VLIB_NODE_STATE_INTERRUPT,
  .n_errors = NETMAP_INPUT_N_ERROR,
  .error_strings = netmap_input_error_strings,

  .n_next_nodes = NETMAP_INPUT_N_NEXT,
  .next_nodes = {
    [NETMAP_INPUT_NEXT_DROP] = "error-drop",
    [NETMAP_INPUT_NEXT_ETHERNET_INPUT] = "ethernet-input",
  },
};