dataplane_node.c

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/*
 * Copyright (c) 2016-2018 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 <stddef.h>
#include <netinet/in.h>

#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vnet/pg/pg.h>
#include <vppinfra/error.h>


#include <acl/acl.h>
#include <vnet/ip/icmp46_packet.h>

#include <plugins/acl/fa_node.h>
#include <plugins/acl/acl.h>
#include <plugins/acl/lookup_context.h>
#include <plugins/acl/public_inlines.h>
#include <plugins/acl/session_inlines.h>

#include <vppinfra/bihash_40_8.h>
#include <vppinfra/bihash_template.h>

typedef struct
{
  u32 next_index;
  u32 sw_if_index;
  u32 lc_index;
  u32 match_acl_in_index;
  u32 match_rule_index;
  u64 packet_info[6];
  u32 trace_bitmap;
  u8 action;
} acl_fa_trace_t;

/* *INDENT-OFF* */
#define foreach_acl_fa_error \
_(ACL_DROP, "ACL deny packets")  \
_(ACL_PERMIT, "ACL permit packets")  \
_(ACL_NEW_SESSION, "new sessions added") \
_(ACL_EXIST_SESSION, "existing session packets") \
_(ACL_CHECK, "checked packets") \
_(ACL_RESTART_SESSION_TIMER, "restart session timer") \
_(ACL_TOO_MANY_SESSIONS, "too many sessions to add new") \
/* end  of errors */

typedef enum
{
#define _(sym,str) ACL_FA_ERROR_##sym,
  foreach_acl_fa_error
#undef _
    ACL_FA_N_ERROR,
} acl_fa_error_t;

/* *INDENT-ON* */

typedef struct
{
  u32 next_index;
  u32 sw_if_index;
  u16 ethertype;
} nonip_in_out_trace_t;

/* packet trace format function */
static u8 *
format_nonip_in_out_trace (u8 * s, u32 is_output, 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 *);
  nonip_in_out_trace_t *t = va_arg (*args, nonip_in_out_trace_t *);

  s = format (s, "%s: sw_if_index %d next_index %x ethertype %x",
              is_output ? "OUT-ETHER-WHITELIST" : "IN-ETHER-WHITELIST",
              t->sw_if_index, t->next_index, t->ethertype);
  return s;
}

static u8 *
format_l2_nonip_in_trace (u8 * s, va_list * args)
{
  return format_nonip_in_out_trace (s, 0, args);
}

static u8 *
format_l2_nonip_out_trace (u8 * s, va_list * args)
{
  return format_nonip_in_out_trace (s, 1, args);
}

#define foreach_nonip_in_error                    \
_(DROP, "dropped inbound non-whitelisted non-ip packets") \
_(PERMIT, "permitted inbound whitelisted non-ip packets") \


#define foreach_nonip_out_error                    \
_(DROP, "dropped outbound non-whitelisted non-ip packets") \
_(PERMIT, "permitted outbound whitelisted non-ip packets") \


/* *INDENT-OFF* */

typedef enum
{
#define _(sym,str) FA_IN_NONIP_ERROR_##sym,
  foreach_nonip_in_error
#undef _
    FA_IN_NONIP_N_ERROR,
} l2_in_feat_arc_error_t;

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

typedef enum
{
#define _(sym,str) FA_OUT_NONIP_ERROR_##sym,
  foreach_nonip_out_error
#undef _
    FA_OUT_NONIP_N_ERROR,
} l2_out_feat_arc_error_t;

static char *fa_out_nonip_error_strings[] = {
#define _(sym,string) string,
  foreach_nonip_out_error
#undef _
};
/* *INDENT-ON* */


always_inline int
is_permitted_ethertype (acl_main_t * am, int sw_if_index0, int is_output,
                        u16 ethertype)
{
  u16 **v = is_output
    ? am->output_etype_whitelist_by_sw_if_index
    : am->input_etype_whitelist_by_sw_if_index;
  u16 *whitelist = vec_elt (v, sw_if_index0);
  int i;

  if (vec_len (whitelist) == 0)
    return 1;

  for (i = 0; i < vec_len (whitelist); i++)
    if (whitelist[i] == ethertype)
      return 1;
  return 0;
}

#define get_u16(addr) ( *((u16 *)(addr)) )

always_inline uword
nonip_in_out_node_fn (vlib_main_t * vm,
                      vlib_node_runtime_t * node, vlib_frame_t * frame,
                      int is_output)
{
  acl_main_t *am = &acl_main;
  u32 n_left, *from;
  u16 nexts[VLIB_FRAME_SIZE], *next;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
  vlib_node_runtime_t *error_node;

  from = vlib_frame_vector_args (frame);
  error_node = vlib_node_get_runtime (vm, node->node_index);
  vlib_get_buffers (vm, from, bufs, frame->n_vectors);
  /* set the initial values for the current buffer the next pointers */
  b = bufs;
  next = nexts;

  n_left = frame->n_vectors;
  while (n_left > 0)
    {
      u32 next_index = 0;
      u32 sw_if_index0 =
        vnet_buffer (b[0])->sw_if_index[is_output ? VLIB_TX : VLIB_RX];
      u16 ethertype = 0;

      int error0 = 0;

      ethernet_header_t *h0 = vlib_buffer_get_current (b[0]);
      u8 *l3h0 = (u8 *) h0 + vnet_buffer (b[0])->l2.l2_len;
      ethertype = clib_net_to_host_u16 (get_u16 (l3h0 - 2));

      if (is_permitted_ethertype (am, sw_if_index0, is_output, ethertype))
        vnet_feature_next (&next_index, b[0]);

      next[0] = next_index;

      if (0 == next[0])
        b[0]->error = error_node->errors[error0];

      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
                         && (b[0]->flags & VLIB_BUFFER_IS_TRACED)))
        {
          nonip_in_out_trace_t *t =
            vlib_add_trace (vm, node, b[0], sizeof (*t));
          t->sw_if_index = sw_if_index0;
          t->ethertype = ethertype;
          t->next_index = next[0];
        }
      next[0] = next[0] < node->n_next_nodes ? next[0] : 0;

      next++;
      b++;
      n_left--;
    }
  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);

  return frame->n_vectors;
}

VLIB_NODE_FN (acl_in_nonip_node) (vlib_main_t * vm,
                                  vlib_node_runtime_t * node,
                                  vlib_frame_t * frame)
{
  return nonip_in_out_node_fn (vm, node, frame, 0);
}

VLIB_NODE_FN (acl_out_nonip_node) (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame)
{
  return nonip_in_out_node_fn (vm, node, frame, 1);
}


/* *INDENT-OFF* */

VLIB_REGISTER_NODE (acl_in_nonip_node) =
{
  .name = "acl-plugin-in-nonip-l2",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_nonip_in_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (fa_in_nonip_error_strings),
  .error_strings = fa_in_nonip_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_in_l2_nonip_fa_feature, static) =
{
  .arc_name = "l2-input-nonip",
  .node_name = "acl-plugin-in-nonip-l2",
  .runs_before = VNET_FEATURES ("l2-input-feat-arc-end"),
};

VLIB_REGISTER_NODE (acl_out_nonip_node) =
{
  .name = "acl-plugin-out-nonip-l2",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_nonip_out_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (fa_out_nonip_error_strings),
  .error_strings = fa_out_nonip_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_out_l2_nonip_fa_feature, static) =
{
  .arc_name = "l2-output-nonip",
  .node_name = "acl-plugin-out-nonip-l2",
  .runs_before = VNET_FEATURES ("l2-output-feat-arc-end"),
};

/* *INDENT-ON* */



always_inline u16
get_current_policy_epoch (acl_main_t * am, int is_input, u32 sw_if_index0)
{
  u32 **p_epoch_vec =
    is_input ? &am->input_policy_epoch_by_sw_if_index :
    &am->output_policy_epoch_by_sw_if_index;
  u16 current_policy_epoch =
    sw_if_index0 < vec_len (*p_epoch_vec) ? vec_elt (*p_epoch_vec,
                                                     sw_if_index0)
    : (is_input * FA_POLICY_EPOCH_IS_INPUT);
  return current_policy_epoch;
}

always_inline void
maybe_trace_buffer (vlib_main_t * vm, vlib_node_runtime_t * node,
                    vlib_buffer_t * b, u32 sw_if_index0, u32 lc_index0,
                    u16 next0, int match_acl_in_index, int match_rule_index,
                    fa_5tuple_t * fa_5tuple, u8 action, u32 trace_bitmap)
{
  if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
    {
      acl_fa_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
      t->sw_if_index = sw_if_index0;
      t->lc_index = lc_index0;
      t->next_index = next0;
      t->match_acl_in_index = match_acl_in_index;
      t->match_rule_index = match_rule_index;
      t->packet_info[0] = fa_5tuple->kv_40_8.key[0];
      t->packet_info[1] = fa_5tuple->kv_40_8.key[1];
      t->packet_info[2] = fa_5tuple->kv_40_8.key[2];
      t->packet_info[3] = fa_5tuple->kv_40_8.key[3];
      t->packet_info[4] = fa_5tuple->kv_40_8.key[4];
      t->packet_info[5] = fa_5tuple->kv_40_8.value;
      t->action = action;
      t->trace_bitmap = trace_bitmap;
    }
}


always_inline int
stale_session_deleted (acl_main_t * am, int is_input,
                       acl_fa_per_worker_data_t * pw, u64 now,
                       u32 sw_if_index0, fa_full_session_id_t f_sess_id)
{
  u16 current_policy_epoch =
    get_current_policy_epoch (am, is_input, sw_if_index0);

  /* if the MSB of policy epoch matches but not the LSB means it is a stale session */
  if ((0 ==
       ((current_policy_epoch ^
         f_sess_id.intf_policy_epoch) &
        FA_POLICY_EPOCH_IS_INPUT))
      && (current_policy_epoch != f_sess_id.intf_policy_epoch))
    {
      /* delete session and increment the counter */
      vec_validate (pw->fa_session_epoch_change_by_sw_if_index, sw_if_index0);
      vec_elt (pw->fa_session_epoch_change_by_sw_if_index, sw_if_index0)++;
      if (acl_fa_conn_list_delete_session (am, f_sess_id, now))
        {
          /* delete the session only if we were able to unlink it */
          acl_fa_two_stage_delete_session (am, sw_if_index0, f_sess_id, now);
        }
      return 1;
    }
  else
    return 0;
}





always_inline void
get_sw_if_index_xN (int vector_sz, int is_input, vlib_buffer_t ** b,
                    u32 * out_sw_if_index)
{
  int ii;
  for (ii = 0; ii < vector_sz; ii++)
    if (is_input)
      out_sw_if_index[ii] = vnet_buffer (b[ii])->sw_if_index[VLIB_RX];
    else
      out_sw_if_index[ii] = vnet_buffer (b[ii])->sw_if_index[VLIB_TX];
}

always_inline void
fill_5tuple_xN (int vector_sz, acl_main_t * am, int is_ip6, int is_input,
                int is_l2_path, vlib_buffer_t ** b, u32 * sw_if_index,
                fa_5tuple_t * out_fa_5tuple)
{
  int ii;
  for (ii = 0; ii < vector_sz; ii++)
    acl_fill_5tuple (am, sw_if_index[ii], b[ii], is_ip6,
                     is_input, is_l2_path, &out_fa_5tuple[ii]);
}

always_inline void
make_session_hash_xN (int vector_sz, acl_main_t * am, int is_ip6,
                      u32 * sw_if_index, fa_5tuple_t * fa_5tuple,
                      u64 * out_hash)
{
  int ii;
  for (ii = 0; ii < vector_sz; ii++)
    out_hash[ii] =
      acl_fa_make_session_hash (am, is_ip6, sw_if_index[ii], &fa_5tuple[ii]);
}

always_inline void
prefetch_session_entry (acl_main_t * am, fa_full_session_id_t f_sess_id)
{
  fa_session_t *sess = get_session_ptr_no_check (am, f_sess_id.thread_index,
                                                 f_sess_id.session_index);
  CLIB_PREFETCH (sess, 2 * CLIB_CACHE_LINE_BYTES, STORE);
}

always_inline u8
process_established_session (vlib_main_t * vm, acl_main_t * am,
                             u32 counter_node_index, int is_input, u64 now,
                             fa_full_session_id_t f_sess_id,
                             u32 * sw_if_index, fa_5tuple_t * fa_5tuple,
                             u32 pkt_len, int node_trace_on,
                             u32 * trace_bitmap)
{
  u8 action = 0;
  fa_session_t *sess = get_session_ptr_no_check (am, f_sess_id.thread_index,
                                                 f_sess_id.session_index);

  int old_timeout_type = fa_session_get_timeout_type (am, sess);
  action =
    acl_fa_track_session (am, is_input, sw_if_index[0], now,
                          sess, &fa_5tuple[0], pkt_len);
  int new_timeout_type = fa_session_get_timeout_type (am, sess);
  /* Tracking might have changed the session timeout type, e.g. from transient to established */
  if (PREDICT_FALSE (old_timeout_type != new_timeout_type))
    {
      acl_fa_restart_timer_for_session (am, now, f_sess_id);
      vlib_node_increment_counter (vm, counter_node_index,
                                   ACL_FA_ERROR_ACL_RESTART_SESSION_TIMER, 1);
      if (node_trace_on)
        *trace_bitmap |=
          0x00010000 + ((0xff & old_timeout_type) << 8) +
          (0xff & new_timeout_type);
    }
  /*
   * I estimate the likelihood to be very low - the VPP needs
   * to have >64K interfaces to start with and then on
   * exactly 64K indices apart needs to be exactly the same
   * 5-tuple... Anyway, since this probability is nonzero -
   * print an error and drop the unlucky packet.
   * If this shows up in real world, we would need to bump
   * the hash key length.
   */
  if (PREDICT_FALSE (sess->sw_if_index != sw_if_index[0]))
    {
      clib_warning
        ("BUG: session LSB16(sw_if_index)=%d and 5-tuple=%d collision!",
         sess->sw_if_index, sw_if_index[0]);
      action = 0;
    }
  return action;

}

#define ACL_PLUGIN_VECTOR_SIZE 4
#define ACL_PLUGIN_PREFETCH_GAP 3

always_inline void
acl_fa_node_common_prepare_fn (vlib_main_t * vm,
                               vlib_node_runtime_t * node,
                               vlib_frame_t * frame, int is_ip6, int is_input,
                               int is_l2_path, int with_stateful_datapath)
        /* , int node_trace_on,
           int reclassify_sessions) */
{
  u32 n_left, *from;
  acl_main_t *am = &acl_main;
  uword thread_index = os_get_thread_index ();
  acl_fa_per_worker_data_t *pw = &am->per_worker_data[thread_index];

  vlib_buffer_t **b;
  u32 *sw_if_index;
  fa_5tuple_t *fa_5tuple;
  u64 *hash;



  from = vlib_frame_vector_args (frame);
  vlib_get_buffers (vm, from, pw->bufs, frame->n_vectors);

  /* set the initial values for the current buffer the next pointers */
  b = pw->bufs;
  sw_if_index = pw->sw_if_indices;
  fa_5tuple = pw->fa_5tuples;
  hash = pw->hashes;


  /*
   * fill the sw_if_index, 5tuple and session hash,
   * First in strides of size ACL_PLUGIN_VECTOR_SIZE,
   * with buffer prefetch being
   * ACL_PLUGIN_PREFETCH_GAP * ACL_PLUGIN_VECTOR_SIZE entries
   * in front. Then with a simple single loop.
   */

  n_left = frame->n_vectors;
  while (n_left >= (ACL_PLUGIN_PREFETCH_GAP + 1) * ACL_PLUGIN_VECTOR_SIZE)
    {
      const int vec_sz = ACL_PLUGIN_VECTOR_SIZE;
      {
        int ii;
        for (ii = ACL_PLUGIN_PREFETCH_GAP * vec_sz;
             ii < (ACL_PLUGIN_PREFETCH_GAP + 1) * vec_sz; ii++)
          {
            CLIB_PREFETCH (b[ii], CLIB_CACHE_LINE_BYTES, LOAD);
            CLIB_PREFETCH (b[ii]->data, 2 * CLIB_CACHE_LINE_BYTES, LOAD);
          }
      }


      get_sw_if_index_xN (vec_sz, is_input, b, sw_if_index);
      fill_5tuple_xN (vec_sz, am, is_ip6, is_input, is_l2_path, &b[0],
                      &sw_if_index[0], &fa_5tuple[0]);
      if (with_stateful_datapath)
        make_session_hash_xN (vec_sz, am, is_ip6, &sw_if_index[0],
                              &fa_5tuple[0], &hash[0]);

      n_left -= vec_sz;

      fa_5tuple += vec_sz;
      b += vec_sz;
      sw_if_index += vec_sz;
      hash += vec_sz;
    }

  while (n_left > 0)
    {
      const int vec_sz = 1;

      get_sw_if_index_xN (vec_sz, is_input, b, sw_if_index);
      fill_5tuple_xN (vec_sz, am, is_ip6, is_input, is_l2_path, &b[0],
                      &sw_if_index[0], &fa_5tuple[0]);
      if (with_stateful_datapath)
        make_session_hash_xN (vec_sz, am, is_ip6, &sw_if_index[0],
                              &fa_5tuple[0], &hash[0]);

      n_left -= vec_sz;

      fa_5tuple += vec_sz;
      b += vec_sz;
      sw_if_index += vec_sz;
      hash += vec_sz;
    }
}


always_inline uword
acl_fa_inner_node_fn (vlib_main_t * vm,
                      vlib_node_runtime_t * node, vlib_frame_t * frame,
                      int is_ip6, int is_input, int is_l2_path,
                      int with_stateful_datapath, int node_trace_on,
                      int reclassify_sessions)
{
  u32 n_left, *from;
  u32 pkts_exist_session = 0;
  u32 pkts_new_session = 0;
  u32 pkts_acl_permit = 0;
  u32 trace_bitmap = 0;
  acl_main_t *am = &acl_main;
  vlib_node_runtime_t *error_node;
  vlib_error_t no_error_existing_session;
  u64 now = clib_cpu_time_now ();
  uword thread_index = os_get_thread_index ();
  acl_fa_per_worker_data_t *pw = &am->per_worker_data[thread_index];

  u16 *next;
  vlib_buffer_t **b;
  u32 *sw_if_index;
  fa_5tuple_t *fa_5tuple;
  u64 *hash;
  /* for the delayed counters */
  u32 saved_matched_acl_index = 0;
  u32 saved_matched_ace_index = 0;
  u32 saved_packet_count = 0;
  u32 saved_byte_count = 0;

  from = vlib_frame_vector_args (frame);
  error_node = vlib_node_get_runtime (vm, node->node_index);
  no_error_existing_session =
    error_node->errors[ACL_FA_ERROR_ACL_EXIST_SESSION];

  b = pw->bufs;
  next = pw->nexts;
  sw_if_index = pw->sw_if_indices;
  fa_5tuple = pw->fa_5tuples;
  hash = pw->hashes;

  /*
   * Now the "hard" work of session lookups and ACL lookups for new sessions.
   * Due to the complexity, do it for the time being in single loop with
   * the pipeline of three prefetches:
   *    1) bucket for the session bihash
   *    2) data for the session bihash
   *    3) worker session record
   */

  fa_full_session_id_t f_sess_id_next = {.as_u64 = ~0ULL };

  /* find the "next" session so we can kickstart the pipeline */
  if (with_stateful_datapath)
    acl_fa_find_session_with_hash (am, is_ip6, sw_if_index[0], hash[0],
                                   &fa_5tuple[0], &f_sess_id_next.as_u64);

  n_left = frame->n_vectors;
  while (n_left > 0)
    {
      u8 action = 0;
      u32 lc_index0 = ~0;
      int acl_check_needed = 1;
      u32 match_acl_in_index = ~0;
      u32 match_acl_pos = ~0;
      u32 match_rule_index = ~0;

      next[0] = 0;              /* drop by default */

      /* Try to match an existing session first */

      if (with_stateful_datapath)
        {
          fa_full_session_id_t f_sess_id = f_sess_id_next;
          switch (n_left)
            {
            default:
              acl_fa_prefetch_session_bucket_for_hash (am, is_ip6, hash[5]);
              /* fallthrough */
            case 5:
            case 4:
              acl_fa_prefetch_session_data_for_hash (am, is_ip6, hash[3]);
              /* fallthrough */
            case 3:
            case 2:
              acl_fa_find_session_with_hash (am, is_ip6, sw_if_index[1],
                                             hash[1], &fa_5tuple[1],
                                             &f_sess_id_next.as_u64);
              if (f_sess_id_next.as_u64 != ~0ULL)
                {
                  prefetch_session_entry (am, f_sess_id_next);
                }
              /* fallthrough */
            case 1:
              if (f_sess_id.as_u64 != ~0ULL)
                {
                  if (node_trace_on)
                    {
                      trace_bitmap |= 0x80000000;
                    }
                  ASSERT (f_sess_id.thread_index < vec_len (vlib_mains));
                  b[0]->error = no_error_existing_session;
                  acl_check_needed = 0;
                  pkts_exist_session += 1;
                  action =
                    process_established_session (vm, am, node->node_index,
                                                 is_input, now, f_sess_id,
                                                 &sw_if_index[0],
                                                 &fa_5tuple[0],
                                                 b[0]->current_length,
                                                 node_trace_on,
                                                 &trace_bitmap);

                  /* expose the session id to the tracer */
                  if (node_trace_on)
                    {
                      match_rule_index = f_sess_id.session_index;
                    }

                  if (reclassify_sessions)
                    {
                      if (PREDICT_FALSE
                          (stale_session_deleted
                           (am, is_input, pw, now, sw_if_index[0],
                            f_sess_id)))
                        {
                          acl_check_needed = 1;
                          if (node_trace_on)
                            {
                              trace_bitmap |= 0x40000000;
                            }
                          /*
                           * If we have just deleted the session, and the next
                           * buffer is the same 5-tuple, that session prediction
                           * is wrong, correct it.
                           */
                          if ((f_sess_id_next.as_u64 != ~0ULL)
                              && 0 == memcmp (&fa_5tuple[1], &fa_5tuple[0],
                                              sizeof (fa_5tuple[1])))
                            f_sess_id_next.as_u64 = ~0ULL;
                        }
                    }
                }
            }

          if (acl_check_needed)
            {
              if (is_input)
                lc_index0 = am->input_lc_index_by_sw_if_index[sw_if_index[0]];
              else
                lc_index0 =
                  am->output_lc_index_by_sw_if_index[sw_if_index[0]];

              action = 0;       /* deny by default */
              int is_match = acl_plugin_match_5tuple_inline (am, lc_index0,
                                                             (fa_5tuple_opaque_t *) & fa_5tuple[0], is_ip6,
                                                             &action,
                                                             &match_acl_pos,
                                                             &match_acl_in_index,
                                                             &match_rule_index,
                                                             &trace_bitmap);
              if (PREDICT_FALSE
                  (is_match && am->interface_acl_counters_enabled))
                {
                  u32 buf_len = vlib_buffer_length_in_chain (vm, b[0]);
                  vlib_increment_combined_counter (am->combined_acl_counters +
                                                   saved_matched_acl_index,
                                                   thread_index,
                                                   saved_matched_ace_index,
                                                   saved_packet_count,
                                                   saved_byte_count);
                  saved_matched_acl_index = match_acl_in_index;
                  saved_matched_ace_index = match_rule_index;
                  saved_packet_count = 1;
                  saved_byte_count = buf_len;
                  /* prefetch the counter that we are going to increment */
                  vlib_prefetch_combined_counter (am->combined_acl_counters +
                                                  saved_matched_acl_index,
                                                  thread_index,
                                                  saved_matched_ace_index);
                }

              b[0]->error = error_node->errors[action];

              if (1 == action)
                pkts_acl_permit++;

              if (2 == action)
                {
                  if (!acl_fa_can_add_session (am, is_input, sw_if_index[0]))
                    acl_fa_try_recycle_session (am, is_input,
                                                thread_index,
                                                sw_if_index[0], now);

                  if (acl_fa_can_add_session (am, is_input, sw_if_index[0]))
                    {
                      u16 current_policy_epoch =
                        get_current_policy_epoch (am, is_input,
                                                  sw_if_index[0]);
                      fa_full_session_id_t f_sess_id =
                        acl_fa_add_session (am, is_input, is_ip6,
                                            sw_if_index[0],
                                            now, &fa_5tuple[0],
                                            current_policy_epoch);

                      /* perform the accounting for the newly added session */
                      process_established_session (vm, am,
                                                   node->node_index,
                                                   is_input, now,
                                                   f_sess_id,
                                                   &sw_if_index[0],
                                                   &fa_5tuple[0],
                                                   b[0]->current_length,
                                                   node_trace_on,
                                                   &trace_bitmap);
                      pkts_new_session++;
                      /*
                       * If the next 5tuple is the same and we just added the session,
                       * the f_sess_id_next can not be ~0. Correct it.
                       */
                      if ((f_sess_id_next.as_u64 == ~0ULL)
                          && 0 == memcmp (&fa_5tuple[1], &fa_5tuple[0],
                                          sizeof (fa_5tuple[1])))
                        f_sess_id_next = f_sess_id;
                    }
                  else
                    {
                      action = 0;
                      b[0]->error =
                        error_node->errors
                        [ACL_FA_ERROR_ACL_TOO_MANY_SESSIONS];
                    }
                }

            }

          {
            u32 next0;
            /* speculatively get the next0 */
            vnet_feature_next (&next0, b[0]);
            /* if the action is not deny - then use that next */
            next[0] = action ? next0 : 0;
          }

          if (node_trace_on)    // PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
            {
              maybe_trace_buffer (vm, node, b[0], sw_if_index[0], lc_index0,
                                  next[0], match_acl_in_index,
                                  match_rule_index, &fa_5tuple[0], action,
                                  trace_bitmap);
            }

          next++;
          b++;
          fa_5tuple++;
          sw_if_index++;
          hash++;
          n_left -= 1;
        }
    }

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

  /*
   * if we were had an acl match then we have a counter to increment.
   * else it is all zeroes, so this will be harmless.
   */
  vlib_increment_combined_counter (am->combined_acl_counters +
                                   saved_matched_acl_index,
                                   thread_index,
                                   saved_matched_ace_index,
                                   saved_packet_count, saved_byte_count);

  vlib_node_increment_counter (vm, node->node_index,
                               ACL_FA_ERROR_ACL_CHECK, frame->n_vectors);
  vlib_node_increment_counter (vm, node->node_index,
                               ACL_FA_ERROR_ACL_EXIST_SESSION,
                               pkts_exist_session);
  vlib_node_increment_counter (vm, node->node_index,
                               ACL_FA_ERROR_ACL_NEW_SESSION,
                               pkts_new_session);
  vlib_node_increment_counter (vm, node->node_index,
                               ACL_FA_ERROR_ACL_PERMIT, pkts_acl_permit);
  return frame->n_vectors;
}

always_inline uword
acl_fa_outer_node_fn (vlib_main_t * vm,
                      vlib_node_runtime_t * node, vlib_frame_t * frame,
                      int is_ip6, int is_input, int is_l2_path,
                      int do_stateful_datapath)
{
  acl_main_t *am = &acl_main;

  acl_fa_node_common_prepare_fn (vm, node, frame, is_ip6, is_input,
                                 is_l2_path, do_stateful_datapath);

  if (am->reclassify_sessions)
    {
      if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
        return acl_fa_inner_node_fn (vm, node, frame, is_ip6, is_input,
                                     is_l2_path, do_stateful_datapath,
                                     1 /* trace */ ,
                                     1 /* reclassify */ );
      else
        return acl_fa_inner_node_fn (vm, node, frame, is_ip6, is_input,
                                     is_l2_path, do_stateful_datapath, 0,
                                     1 /* reclassify */ );
    }
  else
    {
      if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
        return acl_fa_inner_node_fn (vm, node, frame, is_ip6, is_input,
                                     is_l2_path, do_stateful_datapath,
                                     1 /* trace */ ,
                                     0);
      else
        return acl_fa_inner_node_fn (vm, node, frame, is_ip6, is_input,
                                     is_l2_path, do_stateful_datapath, 0, 0);
    }
}

always_inline uword
acl_fa_node_fn (vlib_main_t * vm,
                vlib_node_runtime_t * node, vlib_frame_t * frame, int is_ip6,
                int is_input, int is_l2_path)
{
  /* select the reclassify/no-reclassify version of the datapath */
  acl_main_t *am = &acl_main;

  if (am->fa_sessions_hash_is_initialized)
    return acl_fa_outer_node_fn (vm, node, frame, is_ip6, is_input,
                                 is_l2_path, 1);
  else
    return acl_fa_outer_node_fn (vm, node, frame, is_ip6, is_input,
                                 is_l2_path, 0);
}


static u8 *
format_fa_5tuple (u8 * s, va_list * args)
{
  fa_5tuple_t *p5t = va_arg (*args, fa_5tuple_t *);
  void *paddr0;
  void *paddr1;
  void *format_address_func;
  void *ip_af;
  void *ip_frag_txt =
    p5t->pkt.is_nonfirst_fragment ? " non-initial fragment" : "";

  if (p5t->pkt.is_ip6)
    {
      ip_af = "ip6";
      format_address_func = format_ip6_address;
      paddr0 = &p5t->ip6_addr[0];
      paddr1 = &p5t->ip6_addr[1];
    }
  else
    {
      ip_af = "ip4";
      format_address_func = format_ip4_address;
      paddr0 = &p5t->ip4_addr[0];
      paddr1 = &p5t->ip4_addr[1];
    }

  s =
    format (s, "lc_index %d l3 %s%s ", p5t->pkt.lc_index, ip_af, ip_frag_txt);
  s =
    format (s, "%U -> %U ", format_address_func, paddr0, format_address_func,
            paddr1);
  s = format (s, "%U ", format_fa_session_l4_key, &p5t->l4);
  s = format (s, "tcp flags (%s) %02x rsvd %x",
              p5t->pkt.tcp_flags_valid ? "valid" : "invalid",
              p5t->pkt.tcp_flags, p5t->pkt.flags_reserved);
  return s;
}

#ifndef CLIB_MARCH_VARIANT
u8 *
format_acl_plugin_5tuple (u8 * s, va_list * args)
{
  return format_fa_5tuple (s, args);
}
#endif

/* packet trace format function */
static u8 *
format_acl_plugin_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 *);
  acl_fa_trace_t *t = va_arg (*args, acl_fa_trace_t *);

  s =
    format (s,
            "acl-plugin: lc_index: %d, sw_if_index %d, next index %d, action: %d, match: acl %d rule %d trace_bits %08x\n"
            "  pkt info %016llx %016llx %016llx %016llx %016llx %016llx",
            t->lc_index, t->sw_if_index, t->next_index, t->action,
            t->match_acl_in_index, t->match_rule_index, t->trace_bitmap,
            t->packet_info[0], t->packet_info[1], t->packet_info[2],
            t->packet_info[3], t->packet_info[4], t->packet_info[5]);

  /* Now also print out the packet_info in a form usable by humans */
  s = format (s, "\n   %U", format_fa_5tuple, t->packet_info);
  return s;
}

/* *INDENT-OFF* */

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

VLIB_NODE_FN (acl_in_l2_ip6_node) (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 1, 1, 1);
}

VLIB_NODE_FN (acl_in_l2_ip4_node) (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 0, 1, 1);
}

VLIB_NODE_FN (acl_out_l2_ip6_node) (vlib_main_t * vm,
                                    vlib_node_runtime_t * node,
                                    vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 1, 0, 1);
}

VLIB_NODE_FN (acl_out_l2_ip4_node) (vlib_main_t * vm,
                                    vlib_node_runtime_t * node,
                                    vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 0, 0, 1);
}

/**** L3 processing path nodes ****/

VLIB_NODE_FN (acl_in_fa_ip6_node) (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 1, 1, 0);
}

VLIB_NODE_FN (acl_in_fa_ip4_node) (vlib_main_t * vm,
                                   vlib_node_runtime_t * node,
                                   vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 0, 1, 0);
}

VLIB_NODE_FN (acl_out_fa_ip6_node) (vlib_main_t * vm,
                                    vlib_node_runtime_t * node,
                                    vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 1, 0, 0);
}

VLIB_NODE_FN (acl_out_fa_ip4_node) (vlib_main_t * vm,
                                    vlib_node_runtime_t * node,
                                    vlib_frame_t * frame)
{
  return acl_fa_node_fn (vm, node, frame, 0, 0, 0);
}

VLIB_REGISTER_NODE (acl_in_l2_ip6_node) =
{
  .name = "acl-plugin-in-ip6-l2",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_in_l2_ip6_fa_feature, static) =
{
  .arc_name = "l2-input-ip6",
  .node_name = "acl-plugin-in-ip6-l2",
  .runs_before = VNET_FEATURES ("l2-input-feat-arc-end"),
};

VLIB_REGISTER_NODE (acl_in_l2_ip4_node) =
{
  .name = "acl-plugin-in-ip4-l2",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_in_l2_ip4_fa_feature, static) =
{
  .arc_name = "l2-input-ip4",
  .node_name = "acl-plugin-in-ip4-l2",
  .runs_before = VNET_FEATURES ("l2-input-feat-arc-end"),
};


VLIB_REGISTER_NODE (acl_out_l2_ip6_node) =
{
  .name = "acl-plugin-out-ip6-l2",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_out_l2_ip6_fa_feature, static) =
{
  .arc_name = "l2-output-ip6",
  .node_name = "acl-plugin-out-ip6-l2",
  .runs_before = VNET_FEATURES ("l2-output-feat-arc-end"),
};


VLIB_REGISTER_NODE (acl_out_l2_ip4_node) =
{
  .name = "acl-plugin-out-ip4-l2",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_out_l2_ip4_fa_feature, static) =
{
  .arc_name = "l2-output-ip4",
  .node_name = "acl-plugin-out-ip4-l2",
  .runs_before = VNET_FEATURES ("l2-output-feat-arc-end"),
};


VLIB_REGISTER_NODE (acl_in_fa_ip6_node) =
{
  .name = "acl-plugin-in-ip6-fa",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_in_ip6_fa_feature, static) =
{
  .arc_name = "ip6-unicast",
  .node_name = "acl-plugin-in-ip6-fa",
  .runs_before = VNET_FEATURES ("ip6-flow-classify"),
};

VLIB_REGISTER_NODE (acl_in_fa_ip4_node) =
{
  .name = "acl-plugin-in-ip4-fa",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_in_ip4_fa_feature, static) =
{
  .arc_name = "ip4-unicast",
  .node_name = "acl-plugin-in-ip4-fa",
  .runs_before = VNET_FEATURES ("ip4-flow-classify"),
};


VLIB_REGISTER_NODE (acl_out_fa_ip6_node) =
{
  .name = "acl-plugin-out-ip6-fa",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_out_ip6_fa_feature, static) =
{
  .arc_name = "ip6-output",
  .node_name = "acl-plugin-out-ip6-fa",
  .runs_before = VNET_FEATURES ("interface-output"),
};

VLIB_REGISTER_NODE (acl_out_fa_ip4_node) =
{
  .name = "acl-plugin-out-ip4-fa",
  .vector_size = sizeof (u32),
  .format_trace = format_acl_plugin_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (acl_fa_error_strings),
  .error_strings = acl_fa_error_strings,
  .n_next_nodes = ACL_FA_N_NEXT,
    /* edit / add dispositions here */
  .next_nodes =
  {
    [ACL_FA_ERROR_DROP] = "error-drop",
  }
};

VNET_FEATURE_INIT (acl_out_ip4_fa_feature, static) =
{
  .arc_name = "ip4-output",
  .node_name = "acl-plugin-out-ip4-fa",
  .runs_before = VNET_FEATURES ("interface-output"),
};

/* *INDENT-ON* */

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