l2_input_vtr.c

Go to the documentation of this file.

/*
 * l2_input_vtr.c : layer 2 input vlan tag rewrite processing
 *
 * Copyright (c) 2013 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 <vnet/vnet.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ethernet/packet.h>
#include <vnet/l2/l2_input.h>
#include <vnet/l2/feat_bitmap.h>
#include <vnet/l2/l2_vtr.h>
#include <vnet/l2/l2_input_vtr.h>
#include <vnet/l2/l2_output.h>

#include <vppinfra/error.h>
#include <vppinfra/cache.h>


typedef struct {
  /* per-pkt trace data */ 
  u8  src[6];
  u8  dst[6];
  u8  raw[12]; // raw data (vlans)
  u32 sw_if_index;
} l2_invtr_trace_t;

/* packet trace format function */
static u8 * format_l2_invtr_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 *);
  l2_invtr_trace_t * t = va_arg (*args, l2_invtr_trace_t *);
  
  s = format (s, "l2-input-vtr: sw_if_index %d dst %U src %U data "
              "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
              t->sw_if_index,
              format_ethernet_address, t->dst,
              format_ethernet_address, t->src,
              t->raw[0], t->raw[1], t->raw[2], t->raw[3], t->raw[4], t->raw[5],
              t->raw[6], t->raw[7], t->raw[8], t->raw[9], t->raw[10], t->raw[11]);
  return s;
}

l2_invtr_main_t l2_invtr_main;

static vlib_node_registration_t l2_invtr_node;

#define foreach_l2_invtr_error                  \
_(L2_INVTR,    "L2 inverter packets")           \
_(DROP,        "L2 input tag rewrite drops")

typedef enum {
#define _(sym,str) L2_INVTR_ERROR_##sym,
  foreach_l2_invtr_error
#undef _
  L2_INVTR_N_ERROR,
} l2_invtr_error_t;

static char * l2_invtr_error_strings[] = {
#define _(sym,string) string,
  foreach_l2_invtr_error
#undef _
};

typedef enum {
  L2_INVTR_NEXT_DROP,
  L2_INVTR_N_NEXT,
} l2_invtr_next_t;


static uword
l2_invtr_node_fn (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
                  vlib_frame_t * frame)
{
  u32 n_left_from, * from, * to_next;
  l2_invtr_next_t next_index;
  l2_invtr_main_t * msm = &l2_invtr_main;
  // vlib_node_t *n = vlib_get_node (vm, l2_invtr_node.index);
  // u32 node_counter_base_index = n->error_heap_index;
  // vlib_error_main_t * em = &vm->error_main;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors; /* number of packets to process */
  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      /* get space to enqueue frame to graph node "next_index" */
      vlib_get_next_frame (vm, node, next_index,
                           to_next, n_left_to_next);

      while (n_left_from >= 6 && n_left_to_next >= 2)
        {
          u32 bi0, bi1;
          vlib_buffer_t * b0, * b1;
          u32 next0, next1;
          u32 sw_if_index0, sw_if_index1;
          u32 feature_bitmap0, feature_bitmap1;
         
          /* Prefetch next iteration. */
          {
            vlib_buffer_t * p2, * p3, * p4, * p5;
            u32 sw_if_index2, sw_if_index3;
            
            p2 = vlib_get_buffer (vm, from[2]);
            p3 = vlib_get_buffer (vm, from[3]);
            p4 = vlib_get_buffer (vm, from[4]);
            p5 = vlib_get_buffer (vm, from[5]);
             
            // Prefetch the buffer header and packet for the N+2 loop iteration
            vlib_prefetch_buffer_header (p4, LOAD);
            vlib_prefetch_buffer_header (p5, LOAD);

            CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
            CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);

            // Prefetch the input config for the N+1 loop iteration
            // This depends on the buffer header above
            sw_if_index2 = vnet_buffer(p2)->sw_if_index[VLIB_RX];
            sw_if_index3 = vnet_buffer(p3)->sw_if_index[VLIB_RX];
            CLIB_PREFETCH (vec_elt_at_index(l2output_main.configs, sw_if_index2), CLIB_CACHE_LINE_BYTES, LOAD);
            CLIB_PREFETCH (vec_elt_at_index(l2output_main.configs, sw_if_index3), CLIB_CACHE_LINE_BYTES, LOAD);
          }

          /* speculatively enqueue b0 and b1 to the current next frame */
          /* bi is "buffer index", b is pointer to the buffer */
          to_next[0] = bi0 = from[0];
          to_next[1] = bi1 = from[1];
          from += 2;
          to_next += 2;
          n_left_from -= 2;
          n_left_to_next -= 2;

          b0 = vlib_get_buffer (vm, bi0);
          b1 = vlib_get_buffer (vm, bi1);
 
          /* RX interface handles */
          sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
          sw_if_index1 = vnet_buffer(b1)->sw_if_index[VLIB_RX];

          // process 2 packets
          // em->counters[node_counter_base_index + L2_INVTR_ERROR_L2_INVTR] += 2;

          // Remove ourself from the feature bitmap
          feature_bitmap0 = vnet_buffer(b0)->l2.feature_bitmap & ~L2INPUT_FEAT_VTR;
          feature_bitmap1 = vnet_buffer(b1)->l2.feature_bitmap & ~L2INPUT_FEAT_VTR;

          // save for next feature graph nodes
          vnet_buffer(b0)->l2.feature_bitmap = feature_bitmap0;
          vnet_buffer(b1)->l2.feature_bitmap = feature_bitmap1;

          // Determine the next node
          next0 = feat_bitmap_get_next_node_index(msm->feat_next_node_index,
                                                  feature_bitmap0);
          next1 = feat_bitmap_get_next_node_index(msm->feat_next_node_index,
                                                  feature_bitmap1);

          // perform the tag rewrite on two packets
          if (l2_vtr_process(b0, &(vec_elt_at_index(l2output_main.configs, sw_if_index0)->input_vtr))) {
            // Drop packet
            next0 = L2_INVTR_NEXT_DROP;
            b0->error = node->errors[L2_INVTR_ERROR_DROP];
          }
          if (l2_vtr_process(b1, &(vec_elt_at_index(l2output_main.configs, sw_if_index1)->input_vtr))) {
            // Drop packet
            next1 = L2_INVTR_NEXT_DROP;
            b1->error = node->errors[L2_INVTR_ERROR_DROP];
          }

          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE))) {
            if (b0->flags & VLIB_BUFFER_IS_TRACED) {
              l2_invtr_trace_t *t = 
               vlib_add_trace (vm, node, b0, sizeof (*t));
              ethernet_header_t * h0 = vlib_buffer_get_current (b0);
              t->sw_if_index = sw_if_index0;
              clib_memcpy(t->src, h0->src_address, 6);
              clib_memcpy(t->dst, h0->dst_address, 6);
              clib_memcpy(t->raw, &h0->type, sizeof(t->raw));
            }
            if (b1->flags & VLIB_BUFFER_IS_TRACED) {
              l2_invtr_trace_t *t = 
               vlib_add_trace (vm, node, b1, sizeof (*t));
              ethernet_header_t * h1 = vlib_buffer_get_current (b1);
              t->sw_if_index = sw_if_index0;
              clib_memcpy(t->src, h1->src_address, 6);
              clib_memcpy(t->dst, h1->dst_address, 6);
              clib_memcpy(t->raw, &h1->type, sizeof(t->raw));
            }
          }

          /* verify speculative enqueues, maybe switch current next frame */
          /* if next0==next1==next_index then nothing special needs to be done */
          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;
          vlib_buffer_t * b0;
          u32 next0;
          u32 sw_if_index0;
          u32 feature_bitmap0;

          /* speculatively enqueue b0 to the current next frame */
          bi0 = from[0];
          to_next[0] = bi0;
          from += 1;
          to_next += 1;
          n_left_from -= 1;
          n_left_to_next -= 1;

          b0 = vlib_get_buffer (vm, bi0);

          sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];

          // process 1 packet
          // em->counters[node_counter_base_index + L2_INVTR_ERROR_L2_INVTR] += 1;

          // Remove ourself from the feature bitmap
          feature_bitmap0 = vnet_buffer(b0)->l2.feature_bitmap & ~L2INPUT_FEAT_VTR;

          // save for next feature graph nodes
          vnet_buffer(b0)->l2.feature_bitmap = feature_bitmap0;

          // Determine the next node
          next0 = feat_bitmap_get_next_node_index(msm->feat_next_node_index,
                                                  feature_bitmap0);

          // perform the tag rewrite on one packet
          if (l2_vtr_process(b0, &(vec_elt_at_index(l2output_main.configs, sw_if_index0)->input_vtr))) {
            // Drop packet
            next0 = L2_INVTR_NEXT_DROP;
            b0->error = node->errors[L2_INVTR_ERROR_DROP];
          }

          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE) 
                            && (b0->flags & VLIB_BUFFER_IS_TRACED))) {
            l2_invtr_trace_t *t = 
               vlib_add_trace (vm, node, b0, sizeof (*t));
            ethernet_header_t * h0 = vlib_buffer_get_current (b0);
            t->sw_if_index = sw_if_index0;
            clib_memcpy(t->src, h0->src_address, 6);
            clib_memcpy(t->dst, h0->dst_address, 6);
            clib_memcpy(t->raw, &h0->type, sizeof(t->raw));
          }

          /* verify speculative enqueue, maybe switch current next frame */
          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;
}


VLIB_REGISTER_NODE (l2_invtr_node,static) = {
  .function = l2_invtr_node_fn,
  .name = "l2-input-vtr",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_invtr_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  
  .n_errors = ARRAY_LEN(l2_invtr_error_strings),
  .error_strings = l2_invtr_error_strings,

  .n_next_nodes = L2_INVTR_N_NEXT,

  /* edit / add dispositions here */
  .next_nodes = {
       [L2_INVTR_NEXT_DROP]  = "error-drop",
  },
};

clib_error_t *l2_invtr_init (vlib_main_t *vm)
{
  l2_invtr_main_t * mp = &l2_invtr_main;
 
  mp->vlib_main = vm;
  mp->vnet_main = vnet_get_main();

  // Initialize the feature next-node indexes
  feat_bitmap_init_next_nodes(vm,
                              l2_invtr_node.index,
                              L2INPUT_N_FEAT,
                              l2input_get_feat_names(),
                              mp->feat_next_node_index);

  return 0;
}

VLIB_INIT_FUNCTION (l2_invtr_init);