l2_output_classify.c

Go to the documentation of this file.

/*
 * 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.
 */

#include <vnet/l2/l2_classify.h>
#include <vnet/api_errno.h>

/**
 * @file
 * @brief Layer 2 Output Classifier.
 *
 * @sa @ref vnet/vnet/classify/vnet_classify.c
 * @sa @ref vnet/vnet/classify/vnet_classify.h
 */

typedef struct
{
  /** interface handle for the ith packet */
  u32 sw_if_index;
  /** graph arc index selected for this packet */
  u32 next_index;
  /** classifier table which provided the final result */
  u32 table_index;
  /** offset in classifier heap of the corresponding session */
  u32 session_offset;
} l2_output_classify_trace_t;

typedef struct
{
  /** use-case independent main object pointer */
  vnet_classify_main_t *vcm;
  /** l2 input classifier main object pointer */
  l2_output_classify_main_t *l2cm;
} l2_output_classify_runtime_t;

/** Packet trace format function. */
static u8 *
format_l2_output_classify_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_output_classify_trace_t *t =
    va_arg (*args, l2_output_classify_trace_t *);

  s = format (s, "l2-classify: sw_if_index %d, table %d, offset %x, next %d",
              t->sw_if_index, t->table_index, t->session_offset,
              t->next_index);
  return s;
}

/** l2 output classifier main data structure. */
l2_output_classify_main_t l2_output_classify_main;

vlib_node_registration_t l2_output_classify_node;

#define foreach_l2_output_classify_error               \
_(MISS, "Classify misses")                      \
_(HIT, "Classify hits")                         \
_(CHAIN_HIT, "Classify hits after chain walk")  \
_(DROP, "L2 Classify Drops")

typedef enum
{
#define _(sym,str) L2_OUTPUT_CLASSIFY_ERROR_##sym,
  foreach_l2_output_classify_error
#undef _
    L2_OUTPUT_CLASSIFY_N_ERROR,
} l2_output_classify_error_t;

static char *l2_output_classify_error_strings[] = {
#define _(sym,string) string,
  foreach_l2_output_classify_error
#undef _
};

/**
 * @brief l2 output classifier node.
 * @node l2-output-classify
 *
 * This is the l2 output classifier dispatch node
 *
 * @param vm    vlib_main_t corresponding to the current thread.
 * @param node  vlib_node_runtime_t data for this node.
 * @param frame vlib_frame_t whose contents should be dispatched.
 *
 * @par Graph mechanics: buffer metadata, next index usage
 *
 * @em Uses:
 * - <code>(l2_output_classify_runtime_t *)
 *         rt->classify_table_index_by_sw_if_index</code>
 *         Head of the per-interface, perprotocol classifier table chain
 *         for a specific interface. ~0 => send pkts to the next
 *         feature in the L2 feature chain.
 * - <code>vnet_buffer(b)->sw_if_index[VLIB_TX]</code>
 *      - Indicates the @c sw_if_index value of the interface that the
 *      packet was received on.
 * - <code>vnet_buffer (b0)->l2.feature_bitmap</code>
 *      - Used to steer packets across l2 features enabled on the interface
 * - <code>(vnet_classify_entry_t) e0->next_index</code>
 *      - Used to steer traffic when the classifier hits on a session
 * - <code>(vnet_classify_entry_t) e0->advance</code>
 *      - Signed quantity applied via <code>vlib_buffer_advance</code>
 *      when the classifier hits on a session
 * - <code>(vnet_classify_table_t) t0->miss_next_index</code>
 *      - Used to steer traffic when the classifier misses
 *
 * @em Sets:
 * - <code>vnet_buffer (b0)->l2_classify.table_index</code>
 *      - Classifier table index of the first classifier table in
 *      the classifier table chain
 * - <code>vnet_buffer (b0)->l2_classify.hash</code>
 *      - Bounded-index extensible hash corresponding to the
 *      masked fields in the current packet
 * - <code>vnet_buffer (b0)->l2.feature_bitmap</code>
 *      - Used to steer packets across l2 features enabled on the interface
 * - <code>vnet_buffer (b0)->l2_classify.opaque_index</code>
 *      - Copied from the classifier session object upon classifier hit
 *
 * @em Counters:
 * - <code>L2_OUTPUT_CLASSIFY_ERROR_MISS</code> Classifier misses
 * - <code>L2_OUTPUT_CLASSIFY_ERROR_HIT</code> Classifier hits
 * - <code>L2_OUTPUT_CLASSIFY_ERROR_CHAIN_HIT</code>
 *   Classifier hits in other than the first table
 */

static uword
l2_output_classify_node_fn (vlib_main_t * vm,
                            vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  u32 n_left_from, *from, *to_next;
  l2_output_classify_next_t next_index;
  l2_output_classify_main_t *cm = &l2_output_classify_main;
  vnet_classify_main_t *vcm = cm->vnet_classify_main;
  l2_output_classify_runtime_t *rt =
    (l2_output_classify_runtime_t *) node->runtime_data;
  u32 hits = 0;
  u32 misses = 0;
  u32 chain_hits = 0;
  f64 now;
  u32 n_next_nodes;
  u32 sw_if_index0;

  n_next_nodes = node->n_next_nodes;

  now = vlib_time_now (vm);

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

  /* First pass: compute hash */

  while (n_left_from >= 4)
    {
      vlib_buffer_t *b0, *b1;
      u32 bi0, bi1;
      ethernet_header_t *h0, *h1;
      u32 sw_if_index0, sw_if_index1;
      u16 type0, type1;
      int type_index0, type_index1;
      vnet_classify_table_t *t0, *t1;
      u32 table_index0, table_index1;
      u64 hash0, hash1;


      /* prefetch next iteration */
      {
        vlib_buffer_t *p2, *p3;

        p2 = vlib_get_buffer (vm, from[2]);
        p3 = vlib_get_buffer (vm, from[3]);

        vlib_prefetch_buffer_header (p2, STORE);
        CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
        vlib_prefetch_buffer_header (p3, STORE);
        CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
      }

      bi0 = from[0];
      b0 = vlib_get_buffer (vm, bi0);
      h0 = vlib_buffer_get_current (b0);

      bi1 = from[1];
      b1 = vlib_get_buffer (vm, bi1);
      h1 = vlib_buffer_get_current (b1);

      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];
      vnet_buffer (b0)->l2_classify.table_index = ~0;

      sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_TX];
      vnet_buffer (b1)->l2_classify.table_index = ~0;

      /* Select classifier table based on ethertype */
      type0 = clib_net_to_host_u16 (h0->type);
      type1 = clib_net_to_host_u16 (h1->type);

      type_index0 = (type0 == ETHERNET_TYPE_IP4)
        ? L2_OUTPUT_CLASSIFY_TABLE_IP4 : L2_OUTPUT_CLASSIFY_TABLE_OTHER;
      type_index0 = (type0 == ETHERNET_TYPE_IP6)
        ? L2_OUTPUT_CLASSIFY_TABLE_IP6 : type_index0;

      type_index1 = (type1 == ETHERNET_TYPE_IP4)
        ? L2_OUTPUT_CLASSIFY_TABLE_IP4 : L2_OUTPUT_CLASSIFY_TABLE_OTHER;
      type_index1 = (type1 == ETHERNET_TYPE_IP6)
        ? L2_OUTPUT_CLASSIFY_TABLE_IP6 : type_index1;

      vnet_buffer (b0)->l2_classify.table_index =
        table_index0 =
        rt->l2cm->classify_table_index_by_sw_if_index
        [type_index0][sw_if_index0];

      if (table_index0 != ~0)
        {
          t0 = pool_elt_at_index (vcm->tables, table_index0);

          vnet_buffer (b0)->l2_classify.hash = hash0 =
            vnet_classify_hash_packet (t0, (u8 *) h0);
          vnet_classify_prefetch_bucket (t0, hash0);
        }

      vnet_buffer (b1)->l2_classify.table_index =
        table_index1 =
        rt->l2cm->classify_table_index_by_sw_if_index
        [type_index1][sw_if_index1];

      if (table_index1 != ~0)
        {
          t1 = pool_elt_at_index (vcm->tables, table_index1);

          vnet_buffer (b1)->l2_classify.hash = hash1 =
            vnet_classify_hash_packet (t1, (u8 *) h1);
          vnet_classify_prefetch_bucket (t1, hash1);
        }

      from += 2;
      n_left_from -= 2;
    }

  while (n_left_from > 0)
    {
      vlib_buffer_t *b0;
      u32 bi0;
      ethernet_header_t *h0;
      u16 type0;
      u32 type_index0;
      vnet_classify_table_t *t0;
      u32 table_index0;
      u64 hash0;

      bi0 = from[0];
      b0 = vlib_get_buffer (vm, bi0);
      h0 = vlib_buffer_get_current (b0);

      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];
      vnet_buffer (b0)->l2_classify.table_index = ~0;

      /* Select classifier table based on ethertype */
      type0 = clib_net_to_host_u16 (h0->type);

      type_index0 = (type0 == ETHERNET_TYPE_IP4)
        ? L2_OUTPUT_CLASSIFY_TABLE_IP4 : L2_OUTPUT_CLASSIFY_TABLE_OTHER;
      type_index0 = (type0 == ETHERNET_TYPE_IP6)
        ? L2_OUTPUT_CLASSIFY_TABLE_IP6 : type_index0;

      vnet_buffer (b0)->l2_classify.table_index =
        table_index0 = rt->l2cm->classify_table_index_by_sw_if_index
        [type_index0][sw_if_index0];

      if (table_index0 != ~0)
        {
          t0 = pool_elt_at_index (vcm->tables, table_index0);

          vnet_buffer (b0)->l2_classify.hash = hash0 =
            vnet_classify_hash_packet (t0, (u8 *) h0);
          vnet_classify_prefetch_bucket (t0, hash0);
        }
      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 = ~0;
          ethernet_header_t *h0;
          u32 table_index0;
          u64 hash0;
          vnet_classify_table_t *t0;
          vnet_classify_entry_t *e0;

          if (PREDICT_TRUE (n_left_from > 2))
            {
              vlib_buffer_t *p2 = vlib_get_buffer (vm, from[2]);
              u64 phash2;
              u32 table_index2;
              vnet_classify_table_t *tp2;

              /*
               * Prefetch table entry two ahead. Buffer / data
               * were prefetched above...
               */
              table_index2 = vnet_buffer (p2)->l2_classify.table_index;

              if (PREDICT_TRUE (table_index2 != ~0))
                {
                  tp2 = pool_elt_at_index (vcm->tables, table_index2);
                  phash2 = vnet_buffer (p2)->l2_classify.hash;
                  vnet_classify_prefetch_entry (tp2, phash2);
                }
            }

          /* 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 = vlib_buffer_get_current (b0);
          table_index0 = vnet_buffer (b0)->l2_classify.table_index;
          e0 = 0;
          vnet_buffer (b0)->l2_classify.opaque_index = ~0;

          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 < n_next_nodes) ?
                    e0->next_index : next0;
                  hits++;
                }
              else
                {
                  while (1)
                    {
                      if (t0->next_table_index != ~0)
                        t0 = pool_elt_at_index (vcm->tables,
                                                t0->next_table_index);
                      else
                        {
                          next0 = (t0->miss_next_index < n_next_nodes) ?
                            t0->miss_next_index : next0;
                          misses++;
                          break;
                        }

                      hash0 = vnet_classify_hash_packet (t0, (u8 *) h0);
                      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 < n_next_nodes) ?
                            e0->next_index : next0;
                          hits++;
                          chain_hits++;
                          break;
                        }
                    }
                }
            }

          if (PREDICT_FALSE (next0 == 0))
            b0->error = node->errors[L2_OUTPUT_CLASSIFY_ERROR_DROP];

          /* Determine the next node and remove ourself from bitmap */
          if (PREDICT_FALSE (next0 == ~0))
            next0 = vnet_l2_feature_next (b0, cm->l2_out_feat_next,
                                          L2OUTPUT_FEAT_OUTPUT_CLASSIFY);
          else
            vnet_buffer (b0)->l2.feature_bitmap &=
              ~L2OUTPUT_FEAT_OUTPUT_CLASSIFY;

          if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
                             && (b0->flags & VLIB_BUFFER_IS_TRACED)))
            {
              l2_output_classify_trace_t *t =
                vlib_add_trace (vm, node, b0, sizeof (*t));
              t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_TX];
              t->table_index = table_index0;
              t->next_index = next0;
              t->session_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_OUTPUT_CLASSIFY_ERROR_MISS, misses);
  vlib_node_increment_counter (vm, node->node_index,
                               L2_OUTPUT_CLASSIFY_ERROR_HIT, hits);
  vlib_node_increment_counter (vm, node->node_index,
                               L2_OUTPUT_CLASSIFY_ERROR_CHAIN_HIT,
                               chain_hits);
  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (l2_output_classify_node) = {
  .function = l2_output_classify_node_fn,
  .name = "l2-output-classify",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_output_classify_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = ARRAY_LEN(l2_output_classify_error_strings),
  .error_strings = l2_output_classify_error_strings,

  .runtime_data_bytes = sizeof (l2_output_classify_runtime_t),

  .n_next_nodes = L2_OUTPUT_CLASSIFY_N_NEXT,

  /* edit / add dispositions here */
  .next_nodes = {
    [L2_OUTPUT_CLASSIFY_NEXT_DROP]  = "error-drop",
  },
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (l2_output_classify_node,
                              l2_output_classify_node_fn);

/** l2 output classsifier feature initialization. */
clib_error_t *
l2_output_classify_init (vlib_main_t * vm)
{
  l2_output_classify_main_t *cm = &l2_output_classify_main;
  l2_output_classify_runtime_t *rt;

  rt = vlib_node_get_runtime_data (vm, l2_output_classify_node.index);

  cm->vlib_main = vm;
  cm->vnet_main = vnet_get_main ();
  cm->vnet_classify_main = &vnet_classify_main;

  /* Initialize the feature next-node indexes */
  feat_bitmap_init_next_nodes (vm,
                               l2_output_classify_node.index,
                               L2OUTPUT_N_FEAT,
                               l2output_get_feat_names (),
                               cm->l2_out_feat_next);
  rt->l2cm = cm;
  rt->vcm = cm->vnet_classify_main;

  return 0;
}

VLIB_INIT_FUNCTION (l2_output_classify_init);

clib_error_t *
l2_output_classify_worker_init (vlib_main_t * vm)
{
  l2_output_classify_main_t *cm = &l2_output_classify_main;
  l2_output_classify_runtime_t *rt;

  rt = vlib_node_get_runtime_data (vm, l2_output_classify_node.index);

  rt->l2cm = cm;
  rt->vcm = cm->vnet_classify_main;

  return 0;
}

VLIB_WORKER_INIT_FUNCTION (l2_output_classify_worker_init);

/** Enable/disable l2 input classification on a specific interface. */
void
vnet_l2_output_classify_enable_disable (u32 sw_if_index, int enable_disable)
{

  l2output_intf_bitmap_enable (sw_if_index, L2OUTPUT_FEAT_OUTPUT_CLASSIFY,
                               (u32) enable_disable);
}

/** @brief Set l2 per-protocol, per-interface output classification tables.
 *
 *  @param sw_if_index        interface handle
 *  @param ip4_table_index    ip4 classification table index, or ~0
 *  @param ip6_table_index    ip6 classification table index, or ~0
 *  @param other_table_index  non-ip4, non-ip6 classification table index,
 *         or ~0
 *  @returns 0 on success, VNET_API_ERROR_NO_SUCH_TABLE, TABLE2, TABLE3
 *           if the indicated (non-~0) table does not exist.
 */

int
vnet_l2_output_classify_set_tables (u32 sw_if_index,
                                    u32 ip4_table_index,
                                    u32 ip6_table_index,
                                    u32 other_table_index)
{
  l2_output_classify_main_t *cm = &l2_output_classify_main;
  vnet_classify_main_t *vcm = cm->vnet_classify_main;

  /* Assume that we've validated sw_if_index in the API layer */

  if (ip4_table_index != ~0 &&
      pool_is_free_index (vcm->tables, ip4_table_index))
    return VNET_API_ERROR_NO_SUCH_TABLE;

  if (ip6_table_index != ~0 &&
      pool_is_free_index (vcm->tables, ip6_table_index))
    return VNET_API_ERROR_NO_SUCH_TABLE2;

  if (other_table_index != ~0 &&
      pool_is_free_index (vcm->tables, other_table_index))
    return VNET_API_ERROR_NO_SUCH_TABLE3;

  vec_validate
    (cm->classify_table_index_by_sw_if_index[L2_OUTPUT_CLASSIFY_TABLE_IP4],
     sw_if_index);

  vec_validate
    (cm->classify_table_index_by_sw_if_index[L2_OUTPUT_CLASSIFY_TABLE_IP6],
     sw_if_index);

  vec_validate
    (cm->classify_table_index_by_sw_if_index[L2_OUTPUT_CLASSIFY_TABLE_OTHER],
     sw_if_index);

  cm->classify_table_index_by_sw_if_index[L2_OUTPUT_CLASSIFY_TABLE_IP4]
    [sw_if_index] = ip4_table_index;

  cm->classify_table_index_by_sw_if_index[L2_OUTPUT_CLASSIFY_TABLE_IP6]
    [sw_if_index] = ip6_table_index;

  cm->classify_table_index_by_sw_if_index[L2_OUTPUT_CLASSIFY_TABLE_OTHER]
    [sw_if_index] = other_table_index;

  return 0;
}

static clib_error_t *
int_l2_output_classify_command_fn (vlib_main_t * vm,
                                   unformat_input_t * input,
                                   vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  u32 sw_if_index = ~0;
  u32 ip4_table_index = ~0;
  u32 ip6_table_index = ~0;
  u32 other_table_index = ~0;
  int rv;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "intfc %U", unformat_vnet_sw_interface,
                    vnm, &sw_if_index))
        ;
      else if (unformat (input, "ip4-table %d", &ip4_table_index))
        ;
      else if (unformat (input, "ip6-table %d", &ip6_table_index))
        ;
      else if (unformat (input, "other-table %d", &other_table_index))
        ;
      else
        break;
    }

  if (sw_if_index == ~0)
    return clib_error_return (0, "interface must be specified");


  if (ip4_table_index == ~0 && ip6_table_index == ~0
      && other_table_index == ~0)
    {
      vlib_cli_output (vm, "L2 classification disabled");
      vnet_l2_output_classify_enable_disable (sw_if_index, 0 /* enable */ );
      return 0;
    }

  rv = vnet_l2_output_classify_set_tables (sw_if_index, ip4_table_index,
                                           ip6_table_index,
                                           other_table_index);
  switch (rv)
    {
    case 0:
      vnet_l2_output_classify_enable_disable (sw_if_index, 1 /* enable */ );
      break;

    default:
      return clib_error_return (0, "vnet_l2_output_classify_set_tables: %d",
                                rv);
      break;
    }

  return 0;
}

/*?
 * Configure Layer 2 output classification.
 *
 * @cliexpar
 * @cliexstart{set interface l2 output classify intfc <interface-name> [ip4-table <index>] [ip6-table <index>] [other-table <index>]}
 * @cliexend
 * @todo This is incomplete. This needs a detailed description and a
 * practical example.
?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (int_l2_output_classify_cli, static) = {
  .path = "set interface l2 output classify",
  .short_help =
  "set interface l2 output classify intfc <<interface-name>> [ip4-table <n>]\n"
  "  [ip6-table <n>] [other-table <n>]",
  .function = int_l2_output_classify_command_fn,
};
/* *INDENT-ON* */

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