interface_output.c

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/*
 * Copyright (c) 2015 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.
 */
/*
 * interface_output.c: interface output node
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <vnet/vnet.h>
#include <vnet/ip/icmp46_packet.h>
#include <vnet/ethernet/packet.h>
#include <vnet/ip/ip4.h>
#include <vnet/ip/ip6.h>
#include <vnet/udp/udp_packet.h>
#include <vnet/feature/feature.h>
#include <vnet/classify/trace_classify.h>
#include <vnet/interface_output.h>

typedef struct
{
  u32 sw_if_index;
  u32 flags;
  u8 data[128 - 2 * sizeof (u32)];
}
interface_output_trace_t;

#ifndef CLIB_MARCH_VARIANT
u8 *
format_vnet_interface_output_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  vlib_node_t *node = va_arg (*va, vlib_node_t *);
  interface_output_trace_t *t = va_arg (*va, interface_output_trace_t *);
  vnet_main_t *vnm = vnet_get_main ();
  vnet_sw_interface_t *si;
  u32 indent;

  if (t->sw_if_index != (u32) ~ 0)
    {
      indent = format_get_indent (s);

      if (pool_is_free_index
          (vnm->interface_main.sw_interfaces, t->sw_if_index))
        {
          /* the interface may have been deleted by the time the trace is printed */
          s = format (s, "sw_if_index: %d ", t->sw_if_index);
        }
      else
        {
          si = vnet_get_sw_interface (vnm, t->sw_if_index);
          s =
            format (s, "%U ", format_vnet_sw_interface_name, vnm, si,
                    t->flags);
        }
      s =
        format (s, "\n%U%U", format_white_space, indent,
                node->format_buffer ? node->format_buffer : format_hex_bytes,
                t->data, sizeof (t->data));
    }
  return s;
}

static void
vnet_interface_output_trace (vlib_main_t * vm,
                             vlib_node_runtime_t * node,
                             vlib_frame_t * frame, uword n_buffers)
{
  u32 n_left, *from;

  n_left = n_buffers;
  from = vlib_frame_vector_args (frame);

  while (n_left >= 4)
    {
      u32 bi0, bi1;
      vlib_buffer_t *b0, *b1;
      interface_output_trace_t *t0, *t1;

      /* Prefetch next iteration. */
      vlib_prefetch_buffer_with_index (vm, from[2], LOAD);
      vlib_prefetch_buffer_with_index (vm, from[3], LOAD);

      bi0 = from[0];
      bi1 = from[1];

      b0 = vlib_get_buffer (vm, bi0);
      b1 = vlib_get_buffer (vm, bi1);

      if (b0->flags & VLIB_BUFFER_IS_TRACED)
        {
          t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0]));
          t0->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];
          t0->flags = b0->flags;
          clib_memcpy_fast (t0->data, vlib_buffer_get_current (b0),
                            sizeof (t0->data));
        }
      if (b1->flags & VLIB_BUFFER_IS_TRACED)
        {
          t1 = vlib_add_trace (vm, node, b1, sizeof (t1[0]));
          t1->sw_if_index = vnet_buffer (b1)->sw_if_index[VLIB_TX];
          t1->flags = b1->flags;
          clib_memcpy_fast (t1->data, vlib_buffer_get_current (b1),
                            sizeof (t1->data));
        }
      from += 2;
      n_left -= 2;
    }

  while (n_left >= 1)
    {
      u32 bi0;
      vlib_buffer_t *b0;
      interface_output_trace_t *t0;

      bi0 = from[0];

      b0 = vlib_get_buffer (vm, bi0);

      if (b0->flags & VLIB_BUFFER_IS_TRACED)
        {
          t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0]));
          t0->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];
          t0->flags = b0->flags;
          clib_memcpy_fast (t0->data, vlib_buffer_get_current (b0),
                            sizeof (t0->data));
        }
      from += 1;
      n_left -= 1;
    }
}

static_always_inline uword
vnet_interface_output_node_inline (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame,
                                   vnet_main_t * vnm,
                                   vnet_hw_interface_t * hi,
                                   int do_tx_offloads)
{
  vnet_interface_output_runtime_t *rt = (void *) node->runtime_data;
  vnet_sw_interface_t *si;
  u32 n_left_to_tx, *from, *from_end, *to_tx;
  u32 n_bytes, n_buffers, n_packets;
  u32 n_bytes_b0, n_bytes_b1, n_bytes_b2, n_bytes_b3;
  u32 thread_index = vm->thread_index;
  vnet_interface_main_t *im = &vnm->interface_main;
  u32 next_index = VNET_INTERFACE_OUTPUT_NEXT_TX;
  u32 current_config_index = ~0;
  u8 arc = im->output_feature_arc_index;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;

  n_buffers = frame->n_vectors;

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    vnet_interface_output_trace (vm, node, frame, n_buffers);

  from = vlib_frame_vector_args (frame);
  vlib_get_buffers (vm, from, b, n_buffers);

  if (rt->is_deleted)
    return vlib_error_drop_buffers (vm, node, from,
                                    /* buffer stride */ 1,
                                    n_buffers,
                                    VNET_INTERFACE_OUTPUT_NEXT_DROP,
                                    node->node_index,
                                    VNET_INTERFACE_OUTPUT_ERROR_INTERFACE_DELETED);

  si = vnet_get_sw_interface (vnm, rt->sw_if_index);
  hi = vnet_get_sup_hw_interface (vnm, rt->sw_if_index);
  if (!(si->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP) ||
      !(hi->flags & VNET_HW_INTERFACE_FLAG_LINK_UP))
    {
      vlib_simple_counter_main_t *cm;

      cm = vec_elt_at_index (vnm->interface_main.sw_if_counters,
                             VNET_INTERFACE_COUNTER_TX_ERROR);
      vlib_increment_simple_counter (cm, thread_index,
                                     rt->sw_if_index, n_buffers);

      return vlib_error_drop_buffers (vm, node, from,
                                      /* buffer stride */ 1,
                                      n_buffers,
                                      VNET_INTERFACE_OUTPUT_NEXT_DROP,
                                      node->node_index,
                                      VNET_INTERFACE_OUTPUT_ERROR_INTERFACE_DOWN);
    }

  from_end = from + n_buffers;

  /* Total byte count of all buffers. */
  n_bytes = 0;
  n_packets = 0;

  /* interface-output feature arc handling */
  if (PREDICT_FALSE (vnet_have_features (arc, rt->sw_if_index)))
    {
      vnet_feature_config_main_t *fcm;
      fcm = vnet_feature_get_config_main (arc);
      current_config_index = vnet_get_feature_config_index (arc,
                                                            rt->sw_if_index);
      vnet_get_config_data (&fcm->config_main, &current_config_index,
                            &next_index, 0);
    }

  while (from < from_end)
    {
      /* Get new next frame since previous incomplete frame may have less
         than VNET_FRAME_SIZE vectors in it. */
      vlib_get_new_next_frame (vm, node, next_index, to_tx, n_left_to_tx);

      while (from + 8 <= from_end && n_left_to_tx >= 4)
        {
          u32 bi0, bi1, bi2, bi3;
          u32 tx_swif0, tx_swif1, tx_swif2, tx_swif3;
          u32 or_flags;

          /* Prefetch next iteration. */
          vlib_prefetch_buffer_header (b[4], LOAD);
          vlib_prefetch_buffer_header (b[5], LOAD);
          vlib_prefetch_buffer_header (b[6], LOAD);
          vlib_prefetch_buffer_header (b[7], LOAD);

          bi0 = from[0];
          bi1 = from[1];
          bi2 = from[2];
          bi3 = from[3];
          to_tx[0] = bi0;
          to_tx[1] = bi1;
          to_tx[2] = bi2;
          to_tx[3] = bi3;

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

          from += 4;
          to_tx += 4;
          n_left_to_tx -= 4;

          /* Be grumpy about zero length buffers for benefit of
             driver tx function. */
          ASSERT (b[0]->current_length > 0);
          ASSERT (b[1]->current_length > 0);
          ASSERT (b[2]->current_length > 0);
          ASSERT (b[3]->current_length > 0);

          n_bytes_b0 = vlib_buffer_length_in_chain (vm, b[0]);
          n_bytes_b1 = vlib_buffer_length_in_chain (vm, b[1]);
          n_bytes_b2 = vlib_buffer_length_in_chain (vm, b[2]);
          n_bytes_b3 = vlib_buffer_length_in_chain (vm, b[3]);
          tx_swif0 = vnet_buffer (b[0])->sw_if_index[VLIB_TX];
          tx_swif1 = vnet_buffer (b[1])->sw_if_index[VLIB_TX];
          tx_swif2 = vnet_buffer (b[2])->sw_if_index[VLIB_TX];
          tx_swif3 = vnet_buffer (b[3])->sw_if_index[VLIB_TX];

          n_bytes += n_bytes_b0 + n_bytes_b1;
          n_bytes += n_bytes_b2 + n_bytes_b3;
          n_packets += 4;

          if (PREDICT_FALSE (current_config_index != ~0))
            {
              vnet_buffer (b[0])->feature_arc_index = arc;
              vnet_buffer (b[1])->feature_arc_index = arc;
              vnet_buffer (b[2])->feature_arc_index = arc;
              vnet_buffer (b[3])->feature_arc_index = arc;
              b[0]->current_config_index = current_config_index;
              b[1]->current_config_index = current_config_index;
              b[2]->current_config_index = current_config_index;
              b[3]->current_config_index = current_config_index;
            }

          /* update vlan subif tx counts, if required */
          if (PREDICT_FALSE (tx_swif0 != rt->sw_if_index))
            {
              vlib_increment_combined_counter (im->combined_sw_if_counters +
                                               VNET_INTERFACE_COUNTER_TX,
                                               thread_index, tx_swif0, 1,
                                               n_bytes_b0);
            }

          if (PREDICT_FALSE (tx_swif1 != rt->sw_if_index))
            {

              vlib_increment_combined_counter (im->combined_sw_if_counters +
                                               VNET_INTERFACE_COUNTER_TX,
                                               thread_index, tx_swif1, 1,
                                               n_bytes_b1);
            }

          if (PREDICT_FALSE (tx_swif2 != rt->sw_if_index))
            {

              vlib_increment_combined_counter (im->combined_sw_if_counters +
                                               VNET_INTERFACE_COUNTER_TX,
                                               thread_index, tx_swif2, 1,
                                               n_bytes_b2);
            }
          if (PREDICT_FALSE (tx_swif3 != rt->sw_if_index))
            {

              vlib_increment_combined_counter (im->combined_sw_if_counters +
                                               VNET_INTERFACE_COUNTER_TX,
                                               thread_index, tx_swif3, 1,
                                               n_bytes_b3);
            }

          if (do_tx_offloads)
            {
              u32 vnet_buffer_offload_flags =
                (VNET_BUFFER_F_OFFLOAD_TCP_CKSUM |
                 VNET_BUFFER_F_OFFLOAD_UDP_CKSUM |
                 VNET_BUFFER_F_OFFLOAD_IP_CKSUM);
              if (or_flags & vnet_buffer_offload_flags)
                {
                  if (b[0]->flags & vnet_buffer_offload_flags)
                    vnet_calc_checksums_inline
                      (vm, b[0],
                       b[0]->flags & VNET_BUFFER_F_IS_IP4,
                       b[0]->flags & VNET_BUFFER_F_IS_IP6);
                  if (b[1]->flags & vnet_buffer_offload_flags)
                    vnet_calc_checksums_inline
                      (vm, b[1],
                       b[1]->flags & VNET_BUFFER_F_IS_IP4,
                       b[1]->flags & VNET_BUFFER_F_IS_IP6);
                  if (b[2]->flags & vnet_buffer_offload_flags)
                    vnet_calc_checksums_inline
                      (vm, b[2],
                       b[2]->flags & VNET_BUFFER_F_IS_IP4,
                       b[2]->flags & VNET_BUFFER_F_IS_IP6);
                  if (b[3]->flags & vnet_buffer_offload_flags)
                    vnet_calc_checksums_inline
                      (vm, b[3],
                       b[3]->flags & VNET_BUFFER_F_IS_IP4,
                       b[3]->flags & VNET_BUFFER_F_IS_IP6);
                }
            }
          b += 4;

        }

      while (from + 1 <= from_end && n_left_to_tx >= 1)
        {
          u32 bi0;
          u32 tx_swif0;

          bi0 = from[0];
          to_tx[0] = bi0;
          from += 1;
          to_tx += 1;
          n_left_to_tx -= 1;

          /* Be grumpy about zero length buffers for benefit of
             driver tx function. */
          ASSERT (b[0]->current_length > 0);

          n_bytes_b0 = vlib_buffer_length_in_chain (vm, b[0]);
          tx_swif0 = vnet_buffer (b[0])->sw_if_index[VLIB_TX];
          n_bytes += n_bytes_b0;
          n_packets += 1;

          if (PREDICT_FALSE (current_config_index != ~0))
            {
              vnet_buffer (b[0])->feature_arc_index = arc;
              b[0]->current_config_index = current_config_index;
            }

          if (PREDICT_FALSE (tx_swif0 != rt->sw_if_index))
            {

              vlib_increment_combined_counter (im->combined_sw_if_counters +
                                               VNET_INTERFACE_COUNTER_TX,
                                               thread_index, tx_swif0, 1,
                                               n_bytes_b0);
            }

          if (do_tx_offloads)
            {
              if (b[0]->flags &
                  (VNET_BUFFER_F_OFFLOAD_TCP_CKSUM |
                   VNET_BUFFER_F_OFFLOAD_UDP_CKSUM |
                   VNET_BUFFER_F_OFFLOAD_IP_CKSUM))
                vnet_calc_checksums_inline
                  (vm, b[0],
                   b[0]->flags & VNET_BUFFER_F_IS_IP4,
                   b[0]->flags & VNET_BUFFER_F_IS_IP6);
            }
          b += 1;
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_tx);
    }

  /* Update main interface stats. */
  vlib_increment_combined_counter (im->combined_sw_if_counters
                                   + VNET_INTERFACE_COUNTER_TX,
                                   thread_index,
                                   rt->sw_if_index, n_packets, n_bytes);
  return n_buffers;
}
#endif /* CLIB_MARCH_VARIANT */

static_always_inline void vnet_interface_pcap_tx_trace
  (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame,
   int sw_if_index_from_buffer)
{
  u32 n_left_from, *from;
  u32 sw_if_index;
  vnet_pcap_t *pp = &vlib_global_main.pcap;

  if (PREDICT_TRUE (pp->pcap_tx_enable == 0))
    return;

  if (sw_if_index_from_buffer == 0)
    {
      vnet_interface_output_runtime_t *rt = (void *) node->runtime_data;
      sw_if_index = rt->sw_if_index;
    }
  else
    sw_if_index = ~0;

  n_left_from = frame->n_vectors;
  from = vlib_frame_vector_args (frame);

  while (n_left_from > 0)
    {
      int classify_filter_result;
      u32 bi0 = from[0];
      vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);
      from++;
      n_left_from--;

      if (pp->filter_classify_table_index != ~0)
        {
          classify_filter_result =
            vnet_is_packet_traced_inline
            (b0, pp->filter_classify_table_index, 0 /* full classify */ );
          if (classify_filter_result)
            pcap_add_buffer (&pp->pcap_main, vm, bi0, pp->max_bytes_per_pkt);
          continue;
        }

      if (sw_if_index_from_buffer)
        sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];

      if (pp->pcap_sw_if_index == 0 || pp->pcap_sw_if_index == sw_if_index)
        {
          vnet_main_t *vnm = vnet_get_main ();
          vnet_hw_interface_t *hi =
            vnet_get_sup_hw_interface (vnm, sw_if_index);
          /* Capture pkt if not filtered, or if filter hits */
          if (hi->trace_classify_table_index == ~0 ||
              vnet_is_packet_traced_inline
              (b0, hi->trace_classify_table_index, 0 /* full classify */ ))
            pcap_add_buffer (&pp->pcap_main, vm, bi0, pp->max_bytes_per_pkt);
        }
    }
}

#ifndef CLIB_MARCH_VARIANT

uword
vnet_interface_output_node (vlib_main_t * vm, vlib_node_runtime_t * node,
                            vlib_frame_t * frame)
{
  vnet_main_t *vnm = vnet_get_main ();
  vnet_hw_interface_t *hi;
  vnet_interface_output_runtime_t *rt = (void *) node->runtime_data;
  hi = vnet_get_sup_hw_interface (vnm, rt->sw_if_index);

  vnet_interface_pcap_tx_trace (vm, node, frame,
                                0 /* sw_if_index_from_buffer */ );

  if (hi->flags & VNET_HW_INTERFACE_FLAG_SUPPORTS_TX_L4_CKSUM_OFFLOAD)
    return vnet_interface_output_node_inline (vm, node, frame, vnm, hi,
                                              /* do_tx_offloads */ 0);
  else
    return vnet_interface_output_node_inline (vm, node, frame, vnm, hi,
                                              /* do_tx_offloads */ 1);
}
#endif /* CLIB_MARCH_VARIANT */

/* Use buffer's sw_if_index[VNET_TX] to choose output interface. */
VLIB_NODE_FN (vnet_per_buffer_interface_output_node) (vlib_main_t * vm,
                                                      vlib_node_runtime_t *
                                                      node,
                                                      vlib_frame_t * frame)
{
  vnet_main_t *vnm = vnet_get_main ();
  u32 n_left_to_next, *from, *to_next;
  u32 n_left_from, next_index;

  vnet_interface_pcap_tx_trace (vm, node, frame,
                                1 /* sw_if_index_from_buffer */ );

  n_left_from = frame->n_vectors;

  from = vlib_frame_vector_args (frame);
  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          u32 bi0, bi1, next0, next1;
          vlib_buffer_t *b0, *b1;
          vnet_hw_interface_t *hi0, *hi1;

          /* Prefetch next iteration. */
          vlib_prefetch_buffer_with_index (vm, from[2], LOAD);
          vlib_prefetch_buffer_with_index (vm, from[3], LOAD);

          bi0 = from[0];
          bi1 = from[1];
          to_next[0] = bi0;
          to_next[1] = bi1;
          from += 2;
          to_next += 2;
          n_left_to_next -= 2;
          n_left_from -= 2;

          b0 = vlib_get_buffer (vm, bi0);
          b1 = vlib_get_buffer (vm, bi1);

          hi0 =
            vnet_get_sup_hw_interface (vnm,
                                       vnet_buffer (b0)->sw_if_index
                                       [VLIB_TX]);
          hi1 =
            vnet_get_sup_hw_interface (vnm,
                                       vnet_buffer (b1)->sw_if_index
                                       [VLIB_TX]);

          next0 = hi0->output_node_next_index;
          next1 = hi1->output_node_next_index;

          vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next,
                                           n_left_to_next, bi0, bi1, next0,
                                           next1);
        }

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0, next0;
          vlib_buffer_t *b0;
          vnet_hw_interface_t *hi0;

          bi0 = from[0];
          to_next[0] = bi0;
          from += 1;
          to_next += 1;
          n_left_to_next -= 1;
          n_left_from -= 1;

          b0 = vlib_get_buffer (vm, bi0);

          hi0 =
            vnet_get_sup_hw_interface (vnm,
                                       vnet_buffer (b0)->sw_if_index
                                       [VLIB_TX]);

          next0 = hi0->output_node_next_index;

          vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
                                           n_left_to_next, bi0, next0);
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return frame->n_vectors;
}

typedef struct vnet_error_trace_t_
{
  u32 sw_if_index;
  i8 details_valid;
  u8 is_ip6;
  u8 pad[2];
  u16 mactype;
  ip46_address_t src, dst;
} vnet_error_trace_t;

static u8 *
format_vnet_error_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
  vnet_error_trace_t *t = va_arg (*va, vnet_error_trace_t *);

  /* Normal, non-catchup trace */
  if (t->details_valid == 0)
    {
      s = format (s, "rx:%U", format_vnet_sw_if_index_name,
                  vnet_get_main (), t->sw_if_index);
    }
  else if (t->details_valid == 1)
    {
      /* The trace capture code didn't understant the mactype */
      s = format (s, "mactype 0x%4x (not decoded)", t->mactype);
    }
  else if (t->details_valid == 2)
    {
      /* Dump the src/dst addresses */
      if (t->is_ip6 == 0)
        s = format (s, "IP4: %U -> %U",
                    format_ip4_address, &t->src.ip4,
                    format_ip4_address, &t->dst.ip4);
      else
        s = format (s, "IP6: %U -> %U",
                    format_ip6_address, &t->src.ip6,
                    format_ip6_address, &t->dst.ip6);
    }
  return s;
}

static void
interface_trace_buffers (vlib_main_t * vm,
                         vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  u32 n_left, *buffers;

  buffers = vlib_frame_vector_args (frame);
  n_left = frame->n_vectors;

  while (n_left >= 4)
    {
      u32 bi0, bi1;
      vlib_buffer_t *b0, *b1;
      vnet_error_trace_t *t0, *t1;

      /* Prefetch next iteration. */
      vlib_prefetch_buffer_with_index (vm, buffers[2], LOAD);
      vlib_prefetch_buffer_with_index (vm, buffers[3], LOAD);

      bi0 = buffers[0];
      bi1 = buffers[1];

      b0 = vlib_get_buffer (vm, bi0);
      b1 = vlib_get_buffer (vm, bi1);

      if (b0->flags & VLIB_BUFFER_IS_TRACED)
        {
          t0 = vlib_add_trace (vm, node, b0,
                               STRUCT_OFFSET_OF (vnet_error_trace_t, pad));
          t0->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
          t0->details_valid = 0;
        }
      if (b1->flags & VLIB_BUFFER_IS_TRACED)
        {
          t1 = vlib_add_trace (vm, node, b1,
                               STRUCT_OFFSET_OF (vnet_error_trace_t, pad));
          t1->sw_if_index = vnet_buffer (b1)->sw_if_index[VLIB_RX];
          t1->details_valid = 0;
        }
      buffers += 2;
      n_left -= 2;
    }

  while (n_left >= 1)
    {
      u32 bi0;
      vlib_buffer_t *b0;
      vnet_error_trace_t *t0;

      bi0 = buffers[0];

      b0 = vlib_get_buffer (vm, bi0);

      if (b0->flags & VLIB_BUFFER_IS_TRACED)
        {
          t0 = vlib_add_trace (vm, node, b0,
                               STRUCT_OFFSET_OF (vnet_error_trace_t, pad));
          t0->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
          t0->details_valid = 0;
        }
      buffers += 1;
      n_left -= 1;
    }
}

typedef enum
{
  VNET_ERROR_DISPOSITION_DROP,
  VNET_ERROR_DISPOSITION_PUNT,
  VNET_ERROR_N_DISPOSITION,
} vnet_error_disposition_t;

static void
drop_catchup_trace (vlib_main_t * vm,
                    vlib_node_runtime_t * node, vlib_buffer_t * b)
{
  /* Can we safely rewind the buffer? If not, fagedaboudit */
  if (b->flags & VNET_BUFFER_F_L2_HDR_OFFSET_VALID)
    {
      vnet_error_trace_t *t;
      ip4_header_t *ip4;
      ip6_header_t *ip6;
      ethernet_header_t *eh;
      i16 delta;

      t = vlib_add_trace (vm, node, b, sizeof (*t));
      delta = vnet_buffer (b)->l2_hdr_offset - b->current_data;
      vlib_buffer_advance (b, delta);

      eh = vlib_buffer_get_current (b);
      /* Save mactype */
      t->mactype = clib_net_to_host_u16 (eh->type);
      t->details_valid = 1;
      switch (t->mactype)
        {
        case ETHERNET_TYPE_IP4:
          ip4 = (void *) (eh + 1);
          t->details_valid = 2;
          t->is_ip6 = 0;
          t->src.ip4.as_u32 = ip4->src_address.as_u32;
          t->dst.ip4.as_u32 = ip4->dst_address.as_u32;
          break;

        case ETHERNET_TYPE_IP6:
          ip6 = (void *) (eh + 1);
          t->details_valid = 2;
          t->is_ip6 = 1;
          clib_memcpy_fast (t->src.as_u8, ip6->src_address.as_u8,
                            sizeof (ip6_address_t));
          clib_memcpy_fast (t->dst.as_u8, ip6->dst_address.as_u8,
                            sizeof (ip6_address_t));
          break;

        default:
          /* Dunno, do nothing, leave details_valid alone */
          break;
        }
      /* Restore current data (probably unnecessary) */
      vlib_buffer_advance (b, -delta);
    }
}

static_always_inline uword
interface_drop_punt (vlib_main_t * vm,
                     vlib_node_runtime_t * node,
                     vlib_frame_t * frame,
                     vnet_error_disposition_t disposition)
{
  u32 *from, n_left, thread_index, *sw_if_index;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
  u32 sw_if_indices[VLIB_FRAME_SIZE];
  vlib_simple_counter_main_t *cm;
  u16 nexts[VLIB_FRAME_SIZE];
  u32 n_trace;
  vnet_main_t *vnm;

  vnm = vnet_get_main ();
  thread_index = vm->thread_index;
  from = vlib_frame_vector_args (frame);
  n_left = frame->n_vectors;
  b = bufs;
  sw_if_index = sw_if_indices;

  vlib_get_buffers (vm, from, bufs, n_left);

  /* "trace add error-drop NNN?" */
  if (PREDICT_FALSE ((n_trace = vlib_get_trace_count (vm, node))))
    {
      /* If pkts aren't otherwise traced... */
      if ((node->flags & VLIB_NODE_FLAG_TRACE) == 0)
        {
          /* Trace them from here */
          node->flags |= VLIB_NODE_FLAG_TRACE;
          while (n_trace && n_left)
            {
              vlib_trace_buffer (vm, node, 0 /* next_index */ ,
                                 b[0], 0 /* follow chain */ );
              /*
               * Here we have a wireshark dissector problem.
               * Packets may be well-formed, or not. We
               * must not blow chunks in any case.
               *
               * Try to produce trace records which will help
               * folks understand what's going on.
               */
              drop_catchup_trace (vm, node, b[0]);

              n_trace--;
              n_left--;
              b++;
            }
        }

      vlib_set_trace_count (vm, node, n_trace);
      b = bufs;
      n_left = frame->n_vectors;
    }

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    interface_trace_buffers (vm, node, frame);

  /* All going to drop regardless, this is just a counting exercise */
  clib_memset (nexts, 0, sizeof (nexts));

  cm = vec_elt_at_index (vnm->interface_main.sw_if_counters,
                         (disposition == VNET_ERROR_DISPOSITION_PUNT
                          ? VNET_INTERFACE_COUNTER_PUNT
                          : VNET_INTERFACE_COUNTER_DROP));

  /* collect the array of interfaces first ... */
  while (n_left >= 4)
    {
      if (n_left >= 12)
        {
          /* Prefetch 8 ahead - there's not much going on in each iteration */
          vlib_prefetch_buffer_header (b[4], LOAD);
          vlib_prefetch_buffer_header (b[5], LOAD);
          vlib_prefetch_buffer_header (b[6], LOAD);
          vlib_prefetch_buffer_header (b[7], LOAD);
        }
      sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
      sw_if_index[1] = vnet_buffer (b[1])->sw_if_index[VLIB_RX];
      sw_if_index[2] = vnet_buffer (b[2])->sw_if_index[VLIB_RX];
      sw_if_index[3] = vnet_buffer (b[3])->sw_if_index[VLIB_RX];

      sw_if_index += 4;
      n_left -= 4;
      b += 4;
    }
  while (n_left)
    {
      sw_if_index[0] = vnet_buffer (b[0])->sw_if_index[VLIB_RX];

      sw_if_index += 1;
      n_left -= 1;
      b += 1;
    }

  /* ... then count against them in blocks */
  n_left = frame->n_vectors;

  while (n_left)
    {
      vnet_sw_interface_t *sw_if0;
      u16 off, count;

      off = frame->n_vectors - n_left;

      sw_if_index = sw_if_indices + off;

      count = clib_count_equal_u32 (sw_if_index, n_left);
      n_left -= count;

      vlib_increment_simple_counter (cm, thread_index, sw_if_index[0], count);

      /* Increment super-interface drop/punt counters for
         sub-interfaces. */
      sw_if0 = vnet_get_sw_interface (vnm, sw_if_index[0]);
      if (sw_if0->sup_sw_if_index != sw_if_index[0])
        vlib_increment_simple_counter
          (cm, thread_index, sw_if0->sup_sw_if_index, count);
    }

  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);

  return frame->n_vectors;
}

static inline void
pcap_drop_trace (vlib_main_t * vm,
                 vnet_interface_main_t * im,
                 vnet_pcap_t * pp, vlib_frame_t * f)
{
  u32 *from;
  u32 n_left = f->n_vectors;
  vlib_buffer_t *b0, *p1;
  u32 bi0;
  i16 save_current_data;
  u16 save_current_length;
  vlib_error_main_t *em = &vm->error_main;
  int do_trace = 0;


  from = vlib_frame_vector_args (f);

  while (n_left > 0)
    {
      if (PREDICT_TRUE (n_left > 1))
        {
          p1 = vlib_get_buffer (vm, from[1]);
          vlib_prefetch_buffer_header (p1, LOAD);
        }

      bi0 = from[0];
      b0 = vlib_get_buffer (vm, bi0);
      from++;
      n_left--;

      /* See if we're pointedly ignoring this specific error */
      if (im->pcap_drop_filter_hash
          && hash_get (im->pcap_drop_filter_hash, b0->error))
        continue;

      do_trace = (pp->pcap_sw_if_index == 0) ||
        pp->pcap_sw_if_index == vnet_buffer (b0)->sw_if_index[VLIB_RX];

      if (PREDICT_FALSE
          (do_trace == 0 && pp->filter_classify_table_index != ~0))
        {
          do_trace = vnet_is_packet_traced_inline
            (b0, pp->filter_classify_table_index, 0 /* full classify */ );
        }

      /* Trace all drops, or drops received on a specific interface */
      if (do_trace)
        {
          save_current_data = b0->current_data;
          save_current_length = b0->current_length;

          /*
           * Typically, we'll need to rewind the buffer
           * if l2_hdr_offset is valid, make sure to rewind to the start of
           * the L2 header. This may not be the buffer start in case we pop-ed
           * vlan tags.
           * Otherwise, rewind to buffer start and hope for the best.
           */
          if (b0->flags & VNET_BUFFER_F_L2_HDR_OFFSET_VALID)
            {
              if (b0->current_data > vnet_buffer (b0)->l2_hdr_offset)
                vlib_buffer_advance (b0,
                                     vnet_buffer (b0)->l2_hdr_offset -
                                     b0->current_data);
            }
          else if (b0->current_data > 0)
            vlib_buffer_advance (b0, (word) - b0->current_data);

          {
            vlib_buffer_t *last = b0;
            u32 error_node_index;
            int drop_string_len;
            vlib_node_t *n;
            /* Length of the error string */
            int error_string_len =
              clib_strnlen (em->error_strings_heap[b0->error], 128);

            /* Dig up the drop node */
            error_node_index = vm->node_main.node_by_error[b0->error];
            n = vlib_get_node (vm, error_node_index);

            /* Length of full drop string, w/ "nodename: " prepended */
            drop_string_len = error_string_len + vec_len (n->name) + 2;

            /* Find the last buffer in the chain */
            while (last->flags & VLIB_BUFFER_NEXT_PRESENT)
              last = vlib_get_buffer (vm, last->next_buffer);

            /*
             * Append <nodename>: <error-string> to the capture,
             * only if we can do that without allocating a new buffer.
             */
            if (PREDICT_TRUE ((last->current_data + last->current_length)
                              < (VLIB_BUFFER_DEFAULT_DATA_SIZE
                                 - drop_string_len)))
              {
                clib_memcpy_fast (last->data + last->current_data +
                                  last->current_length, n->name,
                                  vec_len (n->name));
                clib_memcpy_fast (last->data + last->current_data +
                                  last->current_length + vec_len (n->name),
                                  ": ", 2);
                clib_memcpy_fast (last->data + last->current_data +
                                  last->current_length + vec_len (n->name) +
                                  2, em->error_strings_heap[b0->error],
                                  error_string_len);
                last->current_length += drop_string_len;
                b0->flags &= ~(VLIB_BUFFER_TOTAL_LENGTH_VALID);
                pcap_add_buffer (&pp->pcap_main, vm, bi0,
                                 pp->max_bytes_per_pkt);
                last->current_length -= drop_string_len;
                b0->current_data = save_current_data;
                b0->current_length = save_current_length;
                continue;
              }
          }

          /*
           * Didn't have space in the last buffer, here's the dropped
           * packet as-is
           */
          pcap_add_buffer (&pp->pcap_main, vm, bi0, pp->max_bytes_per_pkt);

          b0->current_data = save_current_data;
          b0->current_length = save_current_length;
        }
    }
}

#ifndef CLIB_MARCH_VARIANT
void
vnet_pcap_drop_trace_filter_add_del (u32 error_index, int is_add)
{
  vnet_interface_main_t *im = &vnet_get_main ()->interface_main;

  if (im->pcap_drop_filter_hash == 0)
    im->pcap_drop_filter_hash = hash_create (0, sizeof (uword));

  if (is_add)
    hash_set (im->pcap_drop_filter_hash, error_index, 1);
  else
    hash_unset (im->pcap_drop_filter_hash, error_index);
}
#endif /* CLIB_MARCH_VARIANT */

VLIB_NODE_FN (interface_drop) (vlib_main_t * vm,
                               vlib_node_runtime_t * node,
                               vlib_frame_t * frame)
{
  vnet_interface_main_t *im = &vnet_get_main ()->interface_main;
  vnet_pcap_t *pp = &vlib_global_main.pcap;

  if (PREDICT_FALSE (pp->pcap_drop_enable))
    pcap_drop_trace (vm, im, pp, frame);

  return interface_drop_punt (vm, node, frame, VNET_ERROR_DISPOSITION_DROP);
}

VLIB_NODE_FN (interface_punt) (vlib_main_t * vm,
                               vlib_node_runtime_t * node,
                               vlib_frame_t * frame)
{
  return interface_drop_punt (vm, node, frame, VNET_ERROR_DISPOSITION_PUNT);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (interface_drop) = {
  .name = "error-drop",
  .vector_size = sizeof (u32),
  .format_trace = format_vnet_error_trace,
  .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED,
  .n_next_nodes = 1,
  .next_nodes = {
    [0] = "drop",
  },
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (interface_punt) = {
  .name = "error-punt",
  .vector_size = sizeof (u32),
  .format_trace = format_vnet_error_trace,
  .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED,
  .n_next_nodes = 1,
  .next_nodes = {
    [0] = "punt",
  },
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (vnet_per_buffer_interface_output_node) = {
  .name = "interface-output",
  .vector_size = sizeof (u32),
};
/* *INDENT-ON* */

static uword
interface_tx_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
                      vlib_frame_t * from_frame)
{
  vnet_main_t *vnm = vnet_get_main ();
  u32 last_sw_if_index = ~0;
  vlib_frame_t *to_frame = 0;
  vnet_hw_interface_t *hw = 0;
  u32 *from, *to_next = 0;
  u32 n_left_from;

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;
  while (n_left_from > 0)
    {
      u32 bi0;
      vlib_buffer_t *b0;
      u32 sw_if_index0;

      bi0 = from[0];
      from++;
      n_left_from--;
      b0 = vlib_get_buffer (vm, bi0);
      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];

      if (PREDICT_FALSE ((last_sw_if_index != sw_if_index0) || to_frame == 0))
        {
          if (to_frame)
            {
              hw = vnet_get_sup_hw_interface (vnm, last_sw_if_index);
              vlib_put_frame_to_node (vm, hw->tx_node_index, to_frame);
            }
          last_sw_if_index = sw_if_index0;
          hw = vnet_get_sup_hw_interface (vnm, sw_if_index0);
          to_frame = vlib_get_frame_to_node (vm, hw->tx_node_index);
          to_next = vlib_frame_vector_args (to_frame);
        }

      to_next[0] = bi0;
      to_next++;
      to_frame->n_vectors++;
    }
  vlib_put_frame_to_node (vm, hw->tx_node_index, to_frame);
  return from_frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (interface_tx) = {
  .function = interface_tx_node_fn,
  .name = "interface-tx",
  .vector_size = sizeof (u32),
  .n_next_nodes = 1,
  .next_nodes = {
    [0] = "error-drop",
  },
};

VNET_FEATURE_ARC_INIT (interface_output, static) =
{
  .arc_name  = "interface-output",
  .start_nodes = VNET_FEATURES (0),
  .last_in_arc = "interface-tx",
  .arc_index_ptr = &vnet_main.interface_main.output_feature_arc_index,
};

VNET_FEATURE_INIT (span_tx, static) = {
  .arc_name = "interface-output",
  .node_name = "span-output",
  .runs_before = VNET_FEATURES ("interface-tx"),
};

VNET_FEATURE_INIT (ipsec_if_tx, static) = {
  .arc_name = "interface-output",
  .node_name = "ipsec-if-output",
  .runs_before = VNET_FEATURES ("interface-tx"),
};

VNET_FEATURE_INIT (interface_tx, static) = {
  .arc_name = "interface-output",
  .node_name = "interface-tx",
  .runs_before = 0,
};
/* *INDENT-ON* */

#ifndef CLIB_MARCH_VARIANT
clib_error_t *
vnet_per_buffer_interface_output_hw_interface_add_del (vnet_main_t * vnm,
                                                       u32 hw_if_index,
                                                       u32 is_create)
{
  vnet_hw_interface_t *hi = vnet_get_hw_interface (vnm, hw_if_index);
  u32 next_index;

  if (hi->output_node_index == 0)
    return 0;

  next_index = vlib_node_add_next
    (vnm->vlib_main, vnet_per_buffer_interface_output_node.index,
     hi->output_node_index);
  hi->output_node_next_index = next_index;

  return 0;
}

VNET_HW_INTERFACE_ADD_DEL_FUNCTION
  (vnet_per_buffer_interface_output_hw_interface_add_del);

void
vnet_set_interface_output_node (vnet_main_t * vnm,
                                u32 hw_if_index, u32 node_index)
{
  ASSERT (node_index);
  vnet_hw_interface_t *hi = vnet_get_hw_interface (vnm, hw_if_index);
  u32 next_index = vlib_node_add_next
    (vnm->vlib_main, vnet_per_buffer_interface_output_node.index, node_index);
  hi->output_node_next_index = next_index;
  hi->output_node_index = node_index;
}
#endif /* CLIB_MARCH_VARIANT */

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