l2_input_acl.c

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/*
 * l2_input_acl.c : layer 2 input acl 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/pg/pg.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ethernet/packet.h>
#include <vnet/ip/ip_packet.h>
#include <vnet/ip/ip4_packet.h>
#include <vnet/ip/ip6_packet.h>
#include <vlib/cli.h>
#include <vnet/l2/l2_input.h>
#include <vnet/l2/feat_bitmap.h>

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

#include <vnet/classify/vnet_classify.h>
#include <vnet/classify/input_acl.h>

typedef struct {

  // Next nodes for each feature
  u32 feat_next_node_index[32];

  /* convenience variables */
  vlib_main_t * vlib_main;
  vnet_main_t * vnet_main;
} l2_inacl_main_t;

typedef struct {
  u32 sw_if_index;
  u32 next_index;
  u32 table_index;
  u32 offset;
} l2_inacl_trace_t;

/* packet trace format function */
static u8 * format_l2_inacl_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_inacl_trace_t * t = va_arg (*args, l2_inacl_trace_t *);
  
  s = format (s, "INACL: sw_if_index %d, next_index %d, table %d, offset %d",
              t->sw_if_index, t->next_index, t->table_index, t->offset);
  return s;
}

l2_inacl_main_t l2_inacl_main;

static vlib_node_registration_t l2_inacl_node;

#define foreach_l2_inacl_error                  \
_(NONE, "valid input ACL packets")              \
_(MISS, "input ACL misses")                     \
_(HIT, "input ACL hits")                        \
_(CHAIN_HIT, "input ACL hits after chain walk") \
_(TABLE_MISS, "input ACL table-miss drops")     \
_(SESSION_DENY, "input ACL session deny drops")


typedef enum {
#define _(sym,str) L2_INACL_ERROR_##sym,
  foreach_l2_inacl_error
#undef _
  L2_INACL_N_ERROR,
} l2_inacl_error_t;

static char * l2_inacl_error_strings[] = {
#define _(sym,string) string,
  foreach_l2_inacl_error
#undef _
};

static uword
l2_inacl_node_fn (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
                  vlib_frame_t * frame)
{
  u32 n_left_from, * from, * to_next;
  acl_next_index_t next_index;
  l2_inacl_main_t * msm = &l2_inacl_main;
  input_acl_main_t * am = &input_acl_main;
  vnet_classify_main_t * vcm = am->vnet_classify_main;
  input_acl_table_id_t tid = INPUT_ACL_TABLE_L2;
  f64 now = vlib_time_now (vm);
  u32 hits = 0;
  u32 misses = 0;
  u32 chain_hits = 0;

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

  /* First pass: compute hashes */
  while (n_left_from > 2)
    {
      vlib_buffer_t * b0, * b1;
      u32 bi0, bi1;
      u8 * h0, * h1;
      u32 sw_if_index0, sw_if_index1;
      u32 table_index0, table_index1;
      vnet_classify_table_t * t0, * t1;

      /* prefetch next iteration */
      {
        vlib_buffer_t * p1, * p2;

        p1 = vlib_get_buffer (vm, from[1]);
        p2 = vlib_get_buffer (vm, from[2]);

        vlib_prefetch_buffer_header (p1, STORE);
        CLIB_PREFETCH (p1->data, CLIB_CACHE_LINE_BYTES, STORE);
        vlib_prefetch_buffer_header (p2, STORE);
        CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
      }

      bi0 = from[0];
      b0 = vlib_get_buffer (vm, bi0);
      h0 = b0->data;

      bi1 = from[1];
      b1 = vlib_get_buffer (vm, bi1);
      h1 = b1->data;

      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
      table_index0 = am->classify_table_index_by_sw_if_index[tid][sw_if_index0];

      sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
      table_index1 = am->classify_table_index_by_sw_if_index[tid][sw_if_index1];

      t0 = pool_elt_at_index (vcm->tables, table_index0);

      t1 = pool_elt_at_index (vcm->tables, table_index1);

      vnet_buffer(b0)->l2_classify.hash =
        vnet_classify_hash_packet (t0, (u8 *) h0);

      vnet_classify_prefetch_bucket (t0, vnet_buffer(b0)->l2_classify.hash);

      vnet_buffer(b1)->l2_classify.hash =
        vnet_classify_hash_packet (t1, (u8 *) h1);

      vnet_classify_prefetch_bucket (t1, vnet_buffer(b1)->l2_classify.hash);

      vnet_buffer(b0)->l2_classify.table_index = table_index0;

      vnet_buffer(b1)->l2_classify.table_index = table_index1;

      from += 2;
      n_left_from -= 2;
    }

  while (n_left_from > 0)
    {
      vlib_buffer_t * b0;
      u32 bi0;
      u8 * h0;
      u32 sw_if_index0;
      u32 table_index0;
      vnet_classify_table_t * t0;

      bi0 = from[0];
      b0 = vlib_get_buffer (vm, bi0);
      h0 = b0->data;

      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
      table_index0 = am->classify_table_index_by_sw_if_index[tid][sw_if_index0];

      t0 = pool_elt_at_index (vcm->tables, table_index0);
      vnet_buffer(b0)->l2_classify.hash =
        vnet_classify_hash_packet (t0, (u8 *) h0);

      vnet_buffer(b0)->l2_classify.table_index = table_index0;
      vnet_classify_prefetch_bucket (t0, vnet_buffer(b0)->l2_classify.hash);

      from++;
      n_left_from--;
    }

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

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      vlib_get_next_frame (vm, node, next_index,
                           to_next, n_left_to_next);

      /* Not enough load/store slots to dual loop... */
      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t * b0;
          u32 next0 = ACL_NEXT_INDEX_DENY;
          u32 table_index0;
          vnet_classify_table_t * t0;
          vnet_classify_entry_t * e0;
          u64 hash0;
          u8 * h0;
          u8 error0;

          /* Stride 3 seems to work best */
          if (PREDICT_TRUE (n_left_from > 3))
            {
              vlib_buffer_t * p1 = vlib_get_buffer(vm, from[3]);
              vnet_classify_table_t * tp1;
              u32 table_index1;
              u64 phash1;

              table_index1 = vnet_buffer(p1)->l2_classify.table_index;

              if (PREDICT_TRUE (table_index1 != ~0))
                {
                  tp1 = pool_elt_at_index (vcm->tables, table_index1);
                  phash1 = vnet_buffer(p1)->l2_classify.hash;
                  vnet_classify_prefetch_entry (tp1, phash1);
                }
            }

          /* 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);
          h0 = b0->data;
          table_index0 = vnet_buffer(b0)->l2_classify.table_index;
          e0 = 0;
          t0 = 0;

          /* Feature bitmap update */
          vnet_buffer(b0)->l2.feature_bitmap &= ~L2INPUT_FEAT_ACL;

          vnet_buffer(b0)->l2_classify.opaque_index = ~0;
          /* Determine the next node */
          next0 = feat_bitmap_get_next_node_index(msm->feat_next_node_index,
                    vnet_buffer(b0)->l2.feature_bitmap);

          if (PREDICT_TRUE(table_index0 != ~0))
            {
              hash0 = vnet_buffer(b0)->l2_classify.hash;
              t0 = pool_elt_at_index (vcm->tables, table_index0);

              e0 = vnet_classify_find_entry (t0, (u8 *) h0, hash0,
                                             now);
              if (e0)
                {
                  vnet_buffer(b0)->l2_classify.opaque_index
                    = e0->opaque_index;
                  vlib_buffer_advance (b0, e0->advance);

                  next0 = (e0->next_index < ACL_NEXT_INDEX_N_NEXT)?
                           e0->next_index:next0;

                  hits++;

                  error0 = (next0 == ACL_NEXT_INDEX_DENY)?
                    L2_INACL_ERROR_SESSION_DENY:L2_INACL_ERROR_NONE;
                  b0->error = node->errors[error0];
                }
              else
                {
                  while (1)
                    {
                      if (PREDICT_TRUE(t0->next_table_index != ~0))
                        t0 = pool_elt_at_index (vcm->tables,
                                                t0->next_table_index);
                      else
                        {
                          next0 = (t0->miss_next_index < ACL_NEXT_INDEX_N_NEXT)?
                                   t0->miss_next_index:next0;

                          misses++;

                          error0 = (next0 == ACL_NEXT_INDEX_DENY)?
                            L2_INACL_ERROR_TABLE_MISS:L2_INACL_ERROR_NONE;
                          b0->error = node->errors[error0];
                          break;
                        }

                      hash0 = vnet_classify_hash_packet (t0, (u8 *) h0);
                      e0 = vnet_classify_find_entry
                        (t0, (u8 *) h0, hash0, now);
                      if (e0)
                        {
                          vlib_buffer_advance (b0, e0->advance);
                          next0 = (e0->next_index < ACL_NEXT_INDEX_N_NEXT)?
                                   e0->next_index:next0;
                          hits++;
                          chain_hits++;

                          error0 = (next0 == ACL_NEXT_INDEX_DENY)?
                            L2_INACL_ERROR_SESSION_DENY:L2_INACL_ERROR_NONE;
                          b0->error = node->errors[error0];
                          break;
                        }
                    }
                }
            }

          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)
                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
            {
              l2_inacl_trace_t *t =
                 vlib_add_trace (vm, node, b0, sizeof (*t));
              t->sw_if_index = vnet_buffer(b0)->sw_if_index[VLIB_RX];
              t->next_index = next0;
              t->table_index = t0 ? t0 - vcm->tables : ~0;
              t->offset = e0 ? vnet_classify_get_offset (t0, e0): ~0;
            }

          /* 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);
    }

  vlib_node_increment_counter (vm, node->node_index,
                               L2_INACL_ERROR_MISS,
                               misses);
  vlib_node_increment_counter (vm, node->node_index,
                               L2_INACL_ERROR_HIT,
                               hits);
  vlib_node_increment_counter (vm, node->node_index,
                               L2_INACL_ERROR_CHAIN_HIT,
                               chain_hits);
  return frame->n_vectors;
}

VLIB_REGISTER_NODE (l2_inacl_node,static) = {
  .function = l2_inacl_node_fn,
  .name = "l2-input-acl",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_inacl_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  
  .n_errors = ARRAY_LEN(l2_inacl_error_strings),
  .error_strings = l2_inacl_error_strings,

  .n_next_nodes = ACL_NEXT_INDEX_N_NEXT,

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

clib_error_t *l2_inacl_init (vlib_main_t *vm)
{
  l2_inacl_main_t * mp = &l2_inacl_main;
 
  mp->vlib_main = vm;
  mp->vnet_main = vnet_get_main();

  // Initialize the feature next-node indexes
  feat_bitmap_init_next_nodes(vm,
                              l2_inacl_node.index,
                              L2INPUT_N_FEAT,
                              l2input_get_feat_names(),
                              mp->feat_next_node_index);

  return 0;
}

VLIB_INIT_FUNCTION (l2_inacl_init);