sctp_input.c

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/*
 * Copyright (c) 2017 SUSE LLC.
 * 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 <vppinfra/sparse_vec.h>
#include <vnet/sctp/sctp.h>
#include <vnet/sctp/sctp_packet.h>
#include <vnet/sctp/sctp_debug.h>
#include <vnet/session/session.h>
#include <math.h>

static char *sctp_error_strings[] = {
#define sctp_error(n,s) s,
#include <vnet/sctp/sctp_error.def>
#undef sctp_error
};

/* All SCTP nodes have the same outgoing arcs */
#define foreach_sctp_state_next                  \
  _ (DROP4, "ip4-drop")                         \
  _ (DROP6, "ip6-drop")                         \
  _ (SCTP4_OUTPUT, "sctp4-output")                \
  _ (SCTP6_OUTPUT, "sctp6-output")

typedef enum _sctp_established_phase_next
{
#define _(s,n) SCTP_ESTABLISHED_PHASE_NEXT_##s,
  foreach_sctp_state_next
#undef _
    SCTP_ESTABLISHED_PHASE_N_NEXT,
} sctp_established_phase_next_t;

typedef enum _sctp_rcv_phase_next
{
#define _(s,n) SCTP_RCV_PHASE_NEXT_##s,
  foreach_sctp_state_next
#undef _
    SCTP_RCV_PHASE_N_NEXT,
} sctp_rcv_phase_next_t;

typedef enum _sctp_listen_phase_next
{
#define _(s,n) SCTP_LISTEN_PHASE_NEXT_##s,
  foreach_sctp_state_next
#undef _
    SCTP_LISTEN_PHASE_N_NEXT,
} sctp_listen_phase_next_t;

typedef enum _sctp_shutdown_phase_next
{
#define _(s,n) SCTP_SHUTDOWN_PHASE_NEXT_##s,
  foreach_sctp_state_next
#undef _
    SCTP_SHUTDOWN_PHASE_N_NEXT,
} sctp_shutdown_phase_next_t;

/* Generic, state independent indices */
typedef enum _sctp_state_next
{
#define _(s,n) SCTP_NEXT_##s,
  foreach_sctp_state_next
#undef _
    SCTP_STATE_N_NEXT,
} sctp_state_next_t;

typedef enum _sctp_input_next
{
  SCTP_INPUT_NEXT_DROP,
  SCTP_INPUT_NEXT_LISTEN_PHASE,
  SCTP_INPUT_NEXT_RCV_PHASE,
  SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
  SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
  SCTP_INPUT_NEXT_PUNT_PHASE,
  SCTP_INPUT_N_NEXT
} sctp_input_next_t;

char *
phase_to_string (u8 phase)
{
  switch (phase)
    {
    case SCTP_INPUT_NEXT_DROP:
      return "SCTP_INPUT_NEXT_DROP";
    case SCTP_INPUT_NEXT_LISTEN_PHASE:
      return "SCTP_INPUT_NEXT_LISTEN_PHASE";
    case SCTP_INPUT_NEXT_RCV_PHASE:
      return "SCTP_INPUT_NEXT_RCV_PHASE";
    case SCTP_INPUT_NEXT_ESTABLISHED_PHASE:
      return "SCTP_INPUT_NEXT_ESTABLISHED_PHASE";
    case SCTP_INPUT_NEXT_SHUTDOWN_PHASE:
      return "SCTP_INPUT_NEXT_SHUTDOWN_PHASE";
    case SCTP_INPUT_NEXT_PUNT_PHASE:
      return "SCTP_INPUT_NEXT_PUNT_PHASE";
    }
  return NULL;
}

#define foreach_sctp4_input_next                 \
  _ (DROP, "error-drop")                         \
  _ (RCV_PHASE, "sctp4-rcv")                    \
  _ (LISTEN_PHASE, "sctp4-listen")       \
  _ (ESTABLISHED_PHASE, "sctp4-established")             \
  _ (SHUTDOWN_PHASE, "sctp4-shutdown")  \
  _ (PUNT_PHASE, "ip4-punt")


#define foreach_sctp6_input_next                 \
  _ (DROP, "error-drop")                         \
  _ (RCV_PHASE, "sctp6-rcv")                    \
  _ (LISTEN_PHASE, "sctp6-listen")       \
  _ (ESTABLISHED_PHASE, "sctp6-established")             \
  _ (SHUTDOWN_PHASE, "sctp6-shutdown")          \
  _ (PUNT_PHASE, "ip6-punt")

static u8
sctp_lookup_is_valid (transport_connection_t * trans_conn,
                      sctp_header_t * sctp_hdr)
{
  sctp_connection_t *sctp_conn =
    sctp_get_connection_from_transport (trans_conn);

  if (!sctp_conn)
    return 1;

  u8 is_valid = (trans_conn->lcl_port == sctp_hdr->dst_port
                 && (sctp_conn->state == SCTP_STATE_CLOSED
                     || trans_conn->rmt_port == sctp_hdr->src_port));

  return is_valid;
}

/**
 * Lookup transport connection
 */
static sctp_connection_t *
sctp_lookup_connection (u32 fib_index, vlib_buffer_t * b, u8 thread_index,
                        u8 is_ip4)
{
  sctp_main_t *tm = vnet_get_sctp_main ();
  sctp_header_t *sctp_hdr;
  transport_connection_t *trans_conn;
  sctp_connection_t *sctp_conn;
  u8 is_filtered, i;
  if (is_ip4)
    {
      ip4_header_t *ip4_hdr;
      ip4_hdr = vlib_buffer_get_current (b);
      sctp_hdr = ip4_next_header (ip4_hdr);
      trans_conn = session_lookup_connection_wt4 (fib_index,
                                                  &ip4_hdr->dst_address,
                                                  &ip4_hdr->src_address,
                                                  sctp_hdr->dst_port,
                                                  sctp_hdr->src_port,
                                                  TRANSPORT_PROTO_SCTP,
                                                  thread_index, &is_filtered);
      if (trans_conn == 0)      /* Not primary connection */
        {
          for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
            {
              if ((tm->connections[thread_index]->sub_conn[i].
                   connection.lcl_ip.ip4.as_u32 ==
                   ip4_hdr->dst_address.as_u32)
                  && (tm->connections[thread_index]->sub_conn[i].
                      connection.rmt_ip.ip4.as_u32 ==
                      ip4_hdr->src_address.as_u32))
                {
                  trans_conn =
                    &tm->connections[thread_index]->sub_conn[i].connection;
                  break;
                }
            }
        }
      ASSERT (trans_conn != 0);
      ASSERT (sctp_lookup_is_valid (trans_conn, sctp_hdr));
    }
  else
    {
      ip6_header_t *ip6_hdr;
      ip6_hdr = vlib_buffer_get_current (b);
      sctp_hdr = ip6_next_header (ip6_hdr);
      trans_conn = session_lookup_connection_wt6 (fib_index,
                                                  &ip6_hdr->dst_address,
                                                  &ip6_hdr->src_address,
                                                  sctp_hdr->dst_port,
                                                  sctp_hdr->src_port,
                                                  TRANSPORT_PROTO_SCTP,
                                                  thread_index, &is_filtered);
      if (trans_conn == 0)      /* Not primary connection */
        {
          for (i = 0; i < MAX_SCTP_CONNECTIONS; i++)
            {
              if ((tm->connections[thread_index]->sub_conn[i].
                   connection.lcl_ip.ip6.as_u64[0] ==
                   ip6_hdr->dst_address.as_u64[0]
                   && tm->connections[thread_index]->sub_conn[i].
                   connection.lcl_ip.ip6.as_u64[1] ==
                   ip6_hdr->dst_address.as_u64[1])
                  && (tm->connections[thread_index]->sub_conn[i].
                      connection.rmt_ip.ip6.as_u64[0] ==
                      ip6_hdr->src_address.as_u64[0]
                      && tm->connections[thread_index]->
                      sub_conn[i].connection.rmt_ip.ip6.as_u64[1] ==
                      ip6_hdr->src_address.as_u64[1]))
                {
                  trans_conn =
                    &tm->connections[thread_index]->sub_conn[i].connection;
                  break;
                }
            }
        }
      ASSERT (trans_conn != 0);
      ASSERT (sctp_lookup_is_valid (trans_conn, sctp_hdr));
    }
  sctp_conn = sctp_get_connection_from_transport (trans_conn);
  return sctp_conn;
}

typedef struct
{
  sctp_header_t sctp_header;
  sctp_connection_t sctp_connection;
} sctp_rx_trace_t;

#define sctp_next_output(is_ip4) (is_ip4 ? SCTP_NEXT_SCTP4_OUTPUT          \
                                        : SCTP_NEXT_SCTP6_OUTPUT)

#define sctp_next_drop(is_ip4) (is_ip4 ? SCTP_NEXT_DROP4                  \
                                      : SCTP_NEXT_DROP6)

void
sctp_set_rx_trace_data (sctp_rx_trace_t * rx_trace,
                        sctp_connection_t * sctp_conn,
                        sctp_header_t * sctp_hdr, vlib_buffer_t * b0,
                        u8 is_ip4)
{
  if (sctp_conn)
    {
      clib_memcpy_fast (&rx_trace->sctp_connection, sctp_conn,
                        sizeof (rx_trace->sctp_connection));
    }
  else
    {
      sctp_hdr = sctp_buffer_hdr (b0);
    }
  clib_memcpy_fast (&rx_trace->sctp_header, sctp_hdr,
                    sizeof (rx_trace->sctp_header));
}

always_inline u16
sctp_calculate_implied_length (ip4_header_t * ip4_hdr, ip6_header_t * ip6_hdr,
                               int is_ip4)
{
  u16 sctp_implied_packet_length = 0;

  if (is_ip4)
    sctp_implied_packet_length =
      clib_net_to_host_u16 (ip4_hdr->length) - ip4_header_bytes (ip4_hdr);
  else
    sctp_implied_packet_length =
      clib_net_to_host_u16 (ip6_hdr->payload_length) - sizeof (ip6_hdr);

  return sctp_implied_packet_length;
}

always_inline u8
sctp_is_bundling (u16 sctp_implied_length,
                  sctp_chunks_common_hdr_t * sctp_common_hdr)
{
  if (sctp_implied_length !=
      sizeof (sctp_header_t) + vnet_sctp_get_chunk_length (sctp_common_hdr))
    return 1;
  return 0;
}

always_inline u16
sctp_handle_operation_err (sctp_header_t * sctp_hdr,
                           sctp_connection_t * sctp_conn, u8 idx,
                           vlib_buffer_t * b, u16 * next0)
{
  sctp_operation_error_t *op_err = (sctp_operation_error_t *) sctp_hdr;

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
    {
      return SCTP_ERROR_INVALID_TAG;
    }

  if (clib_net_to_host_u16 (op_err->err_causes[0].param_hdr.type) ==
      STALE_COOKIE_ERROR)
    {
      if (sctp_conn->state != SCTP_STATE_COOKIE_ECHOED)
        *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      else
        {
          sctp_connection_cleanup (sctp_conn);

          session_transport_closing_notify (&sctp_conn->
                                            sub_conn[idx].connection);
        }
    }

  return SCTP_ERROR_NONE;
}

always_inline u16
sctp_handle_init (sctp_header_t * sctp_hdr,
                  sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                  sctp_connection_t * sctp_conn, vlib_buffer_t * b0,
                  u16 sctp_implied_length)
{
  sctp_init_chunk_t *init_chunk = (sctp_init_chunk_t *) (sctp_hdr);
  ip4_address_t ip4_addr;
  ip6_address_t ip6_addr;
  u8 add_ip4 = 0;
  u8 add_ip6 = 0;
  char hostname[FQDN_MAX_LENGTH];

  /* Check the current state of the connection
   *
   * The logic required by the RFC4960 Section 5.2.2 is already taken care of
   * in the code below and by the "sctp_prepare_initack_chunk" function.
   * However, for debugging purposes it is nice to have a message printed out
   * for these corner-case scenarios.
   */
  if (sctp_conn->state != SCTP_STATE_CLOSED)
    {                           /* UNEXPECTED scenario */
      switch (sctp_conn->state)
        {
        case SCTP_STATE_COOKIE_WAIT:
          SCTP_ADV_DBG ("Received INIT chunk while in COOKIE_WAIT state");
          sctp_prepare_initack_chunk_for_collision (sctp_conn,
                                                    SCTP_PRIMARY_PATH_IDX,
                                                    b0, &ip4_addr, &ip6_addr);
          return SCTP_ERROR_NONE;
        case SCTP_STATE_COOKIE_ECHOED:
        case SCTP_STATE_SHUTDOWN_ACK_SENT:
          SCTP_ADV_DBG ("Received INIT chunk while in COOKIE_ECHOED state");
          if (sctp_conn->forming_association_changed == 0)
            sctp_prepare_initack_chunk_for_collision (sctp_conn,
                                                      SCTP_PRIMARY_PATH_IDX,
                                                      b0, &ip4_addr,
                                                      &ip6_addr);
          else
            sctp_prepare_abort_for_collision (sctp_conn,
                                              SCTP_PRIMARY_PATH_IDX, b0,
                                              &ip4_addr, &ip6_addr);
          return SCTP_ERROR_NONE;
        }
    }

  if (sctp_hdr->verification_tag != 0x0)
    return SCTP_ERROR_INVALID_TAG_FOR_INIT;

  /*
   * It is not possible to bundle any other CHUNK with the INIT chunk
   */
  if (sctp_is_bundling (sctp_implied_length, &init_chunk->chunk_hdr))
    return SCTP_ERROR_BUNDLING_VIOLATION;

  /* Save the INITIATE_TAG of the remote peer for this connection:
   * it MUST be used for the VERIFICATION_TAG parameter in the SCTP HEADER */
  sctp_conn->remote_tag = init_chunk->initiate_tag;
  sctp_conn->remote_initial_tsn =
    clib_net_to_host_u32 (init_chunk->initial_tsn);
  sctp_conn->last_rcvd_tsn = sctp_conn->remote_initial_tsn;
  sctp_conn->next_tsn_expected = sctp_conn->remote_initial_tsn + 1;
  SCTP_CONN_TRACKING_DBG ("sctp_conn->remote_initial_tsn = %u",
                          sctp_conn->remote_initial_tsn);

  sctp_conn->peer_rwnd = clib_net_to_host_u32 (init_chunk->a_rwnd);
  /*
   * If the length specified in the INIT message is bigger than the size in bytes of our structure it means that
   * optional parameters have been sent with the INIT chunk and we need to parse them.
   */
  u16 length = vnet_sctp_get_chunk_length (sctp_chunk_hdr);
  if (length > sizeof (sctp_init_chunk_t))
    {
      /* There are optional parameters in the INIT chunk */
      u16 pointer_offset = sizeof (sctp_init_chunk_t);
      while (pointer_offset < length)
        {
          sctp_opt_params_hdr_t *opt_params_hdr =
            (sctp_opt_params_hdr_t *) init_chunk + pointer_offset;

          switch (clib_net_to_host_u16 (opt_params_hdr->type))
            {
            case SCTP_IPV4_ADDRESS_TYPE:
              {
                sctp_ipv4_addr_param_t *ipv4 =
                  (sctp_ipv4_addr_param_t *) opt_params_hdr;
                clib_memcpy_fast (&ip4_addr, &ipv4->address,
                                  sizeof (ip4_address_t));

                if (sctp_sub_connection_add_ip4 (vlib_get_main (),
                                                 &sctp_conn->sub_conn
                                                 [SCTP_PRIMARY_PATH_IDX].connection.
                                                 lcl_ip.ip4,
                                                 &ipv4->address) ==
                    SCTP_ERROR_NONE)
                  add_ip4 = 1;

                break;
              }
            case SCTP_IPV6_ADDRESS_TYPE:
              {
                sctp_ipv6_addr_param_t *ipv6 =
                  (sctp_ipv6_addr_param_t *) opt_params_hdr;
                clib_memcpy_fast (&ip6_addr, &ipv6->address,
                                  sizeof (ip6_address_t));

                if (sctp_sub_connection_add_ip6 (vlib_get_main (),
                                                 &sctp_conn->sub_conn
                                                 [SCTP_PRIMARY_PATH_IDX].connection.
                                                 lcl_ip.ip6,
                                                 &ipv6->address) ==
                    SCTP_ERROR_NONE)
                  add_ip6 = 1;

                break;
              }
            case SCTP_COOKIE_PRESERVATIVE_TYPE:
              {
                sctp_cookie_preservative_param_t *cookie_pres =
                  (sctp_cookie_preservative_param_t *) opt_params_hdr;
                sctp_conn->peer_cookie_life_span_increment =
                  cookie_pres->life_span_inc;
                break;
              }
            case SCTP_HOSTNAME_ADDRESS_TYPE:
              {
                sctp_hostname_param_t *hostname_addr =
                  (sctp_hostname_param_t *) opt_params_hdr;
                clib_memcpy_fast (hostname, hostname_addr->hostname,
                                  FQDN_MAX_LENGTH);
                break;
              }
            case SCTP_SUPPORTED_ADDRESS_TYPES:
              {
                /* TODO */
                break;
              }
            }
          pointer_offset += clib_net_to_host_u16 (opt_params_hdr->length);
        }
    }

  /* Reuse buffer to make init-ack and send */
  sctp_prepare_initack_chunk (sctp_conn, SCTP_PRIMARY_PATH_IDX, b0, &ip4_addr,
                              add_ip4, &ip6_addr, add_ip6);
  return SCTP_ERROR_NONE;
}

always_inline u16
sctp_is_valid_init_ack (sctp_header_t * sctp_hdr,
                        sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                        sctp_connection_t * sctp_conn, vlib_buffer_t * b0,
                        u16 sctp_implied_length)
{
  sctp_init_ack_chunk_t *init_ack_chunk =
    (sctp_init_ack_chunk_t *) (sctp_hdr);

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != init_ack_chunk->sctp_hdr.verification_tag)
    {
      return SCTP_ERROR_INVALID_TAG;
    }

  /*
   * It is not possible to bundle any other CHUNK with the INIT_ACK chunk
   */
  if (sctp_is_bundling (sctp_implied_length, &init_ack_chunk->chunk_hdr))
    return SCTP_ERROR_BUNDLING_VIOLATION;

  return SCTP_ERROR_NONE;
}

always_inline u16
sctp_handle_init_ack (sctp_header_t * sctp_hdr,
                      sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                      sctp_connection_t * sctp_conn, u8 idx,
                      vlib_buffer_t * b0, u16 sctp_implied_length)
{
  sctp_init_ack_chunk_t *init_ack_chunk =
    (sctp_init_ack_chunk_t *) (sctp_hdr);

  char hostname[FQDN_MAX_LENGTH];

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != init_ack_chunk->sctp_hdr.verification_tag)
    {
      return SCTP_ERROR_INVALID_TAG;
    }

  /*
   * It is not possible to bundle any other CHUNK with the INIT chunk
   */
  if (sctp_is_bundling (sctp_implied_length, &init_ack_chunk->chunk_hdr))
    return SCTP_ERROR_BUNDLING_VIOLATION;

  /* Stop the T1_INIT timer */
  sctp_timer_reset (sctp_conn, idx, SCTP_TIMER_T1_INIT);

  sctp_calculate_rto (sctp_conn, idx);

  /* remote_tag to be placed in the VERIFICATION_TAG field of the COOKIE_ECHO chunk */
  sctp_conn->remote_tag = init_ack_chunk->initiate_tag;
  sctp_conn->remote_initial_tsn =
    clib_net_to_host_u32 (init_ack_chunk->initial_tsn);
  sctp_conn->last_rcvd_tsn = sctp_conn->remote_initial_tsn;
  sctp_conn->next_tsn_expected = sctp_conn->remote_initial_tsn + 1;
  SCTP_CONN_TRACKING_DBG ("sctp_conn->remote_initial_tsn = %u",
                          sctp_conn->remote_initial_tsn);
  sctp_conn->peer_rwnd = clib_net_to_host_u32 (init_ack_chunk->a_rwnd);

  u16 length = vnet_sctp_get_chunk_length (sctp_chunk_hdr);

  if (length > sizeof (sctp_init_ack_chunk_t))
    /*
     * There are optional parameters in the INIT ACK chunk
     */
    {
      u16 pointer_offset = sizeof (sctp_init_ack_chunk_t);

      while (pointer_offset < length)
        {
          sctp_opt_params_hdr_t *opt_params_hdr =
            (sctp_opt_params_hdr_t *) ((char *) init_ack_chunk +
                                       pointer_offset);

          switch (clib_net_to_host_u16 (opt_params_hdr->type))
            {
            case SCTP_IPV4_ADDRESS_TYPE:
              {
                sctp_ipv4_addr_param_t *ipv4 =
                  (sctp_ipv4_addr_param_t *) opt_params_hdr;

                sctp_sub_connection_add_ip4 (vlib_get_main (),
                                             &sctp_conn->sub_conn
                                             [SCTP_PRIMARY_PATH_IDX].connection.
                                             lcl_ip.ip4, &ipv4->address);

                break;
              }
            case SCTP_IPV6_ADDRESS_TYPE:
              {
                sctp_ipv6_addr_param_t *ipv6 =
                  (sctp_ipv6_addr_param_t *) opt_params_hdr;

                sctp_sub_connection_add_ip6 (vlib_get_main (),
                                             &sctp_conn->sub_conn
                                             [SCTP_PRIMARY_PATH_IDX].connection.
                                             lcl_ip.ip6, &ipv6->address);

                break;
              }
            case SCTP_STATE_COOKIE_TYPE:
              {
                sctp_state_cookie_param_t *state_cookie_param =
                  (sctp_state_cookie_param_t *) opt_params_hdr;

                clib_memcpy_fast (&(sctp_conn->cookie_param),
                                  state_cookie_param,
                                  sizeof (sctp_state_cookie_param_t));

                break;
              }
            case SCTP_HOSTNAME_ADDRESS_TYPE:
              {
                sctp_hostname_param_t *hostname_addr =
                  (sctp_hostname_param_t *) opt_params_hdr;
                clib_memcpy_fast (hostname, hostname_addr->hostname,
                                  FQDN_MAX_LENGTH);
                break;
              }
            case SCTP_UNRECOGNIZED_TYPE:
              {
                break;
              }
            }
          u16 increment = clib_net_to_host_u16 (opt_params_hdr->length);
          /* This indicates something really bad happened */
          if (increment == 0)
            {
              return SCTP_ERROR_INVALID_TAG;
            }
          pointer_offset += increment;
        }
    }

  sctp_prepare_cookie_echo_chunk (sctp_conn, idx, b0, 1);

  /* Start the T1_COOKIE timer */
  sctp_timer_set (sctp_conn, idx,
                  SCTP_TIMER_T1_COOKIE, sctp_conn->sub_conn[idx].RTO);

  return SCTP_ERROR_NONE;
}

/** Enqueue data out-of-order for delivery to application */
always_inline int
sctp_session_enqueue_data_ooo (sctp_connection_t * sctp_conn,
                               vlib_buffer_t * b, u16 data_len, u8 conn_idx)
{
  int written, error = SCTP_ERROR_ENQUEUED;

  written =
    session_enqueue_stream_connection (&sctp_conn->
                                       sub_conn[conn_idx].connection, b, 0,
                                       1 /* queue event */ ,
                                       0);

  /* Update next_tsn_expected */
  if (PREDICT_TRUE (written == data_len))
    {
      sctp_conn->next_tsn_expected += written;

      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] == DATA_LEN [%d]",
                    sctp_conn->sub_conn[conn_idx].connection.c_index,
                    written, data_len);
    }
  /* If more data written than expected, account for out-of-order bytes. */
  else if (written > data_len)
    {
      sctp_conn->next_tsn_expected += written;

      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] > DATA_LEN [%d]",
                    sctp_conn->sub_conn[conn_idx].connection.c_index,
                    written, data_len);
    }
  else if (written > 0)
    {
      /* We've written something but FIFO is probably full now */
      sctp_conn->next_tsn_expected += written;

      error = SCTP_ERROR_PARTIALLY_ENQUEUED;

      SCTP_ADV_DBG
        ("CONN = %u, WRITTEN [%u] > 0 (SCTP_ERROR_PARTIALLY_ENQUEUED)",
         sctp_conn->sub_conn[conn_idx].connection.c_index, written);
    }
  else
    {
      SCTP_ADV_DBG ("CONN = %u, WRITTEN == 0 (SCTP_ERROR_FIFO_FULL)",
                    sctp_conn->sub_conn[conn_idx].connection.c_index);

      return SCTP_ERROR_FIFO_FULL;
    }

  /* TODO: Update out_of_order_map & SACK list */

  return error;
}

/** Enqueue data for delivery to application */
always_inline int
sctp_session_enqueue_data (sctp_connection_t * sctp_conn, vlib_buffer_t * b,
                           u16 data_len, u8 conn_idx)
{
  int written, error = SCTP_ERROR_ENQUEUED;

  written =
    session_enqueue_stream_connection (&sctp_conn->
                                       sub_conn[conn_idx].connection, b, 0,
                                       1 /* queue event */ ,
                                       1);

  /* Update next_tsn_expected */
  if (PREDICT_TRUE (written == data_len))
    {
      sctp_conn->next_tsn_expected += written;

      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] == DATA_LEN [%d]",
                    sctp_conn->sub_conn[conn_idx].connection.c_index,
                    written, data_len);
    }
  /* If more data written than expected, account for out-of-order bytes. */
  else if (written > data_len)
    {
      sctp_conn->next_tsn_expected += written;

      SCTP_ADV_DBG ("CONN = %u, WRITTEN [%u] > DATA_LEN [%d]",
                    sctp_conn->sub_conn[conn_idx].connection.c_index,
                    written, data_len);
    }
  else if (written > 0)
    {
      /* We've written something but FIFO is probably full now */
      sctp_conn->next_tsn_expected += written;

      error = SCTP_ERROR_PARTIALLY_ENQUEUED;

      SCTP_ADV_DBG
        ("CONN = %u, WRITTEN [%u] > 0 (SCTP_ERROR_PARTIALLY_ENQUEUED)",
         sctp_conn->sub_conn[conn_idx].connection.c_index, written);
    }
  else
    {
      SCTP_ADV_DBG ("CONN = %u, WRITTEN == 0 (SCTP_ERROR_FIFO_FULL)",
                    sctp_conn->sub_conn[conn_idx].connection.c_index);

      return SCTP_ERROR_FIFO_FULL;
    }

  return error;
}

always_inline u8
sctp_is_sack_delayable (sctp_connection_t * sctp_conn, u8 idx, u8 is_gapping)
{
  if (sctp_conn->conn_config.never_delay_sack)
    {
      SCTP_CONN_TRACKING_DBG ("sctp_conn->conn_config.never_delay_sack = ON");
      return 0;
    }

  /* Section 4.4 of the RFC4960 */
  if (sctp_conn->state == SCTP_STATE_SHUTDOWN_SENT)
    {
      SCTP_CONN_TRACKING_DBG ("sctp_conn->state = %s; SACK not delayable",
                              sctp_state_to_string (sctp_conn->state));
      return 0;
    }

  if (is_gapping)
    {
      SCTP_CONN_TRACKING_DBG
        ("gapping != 0: CONN_INDEX = %u, sctp_conn->ack_state = %u",
         sctp_conn->sub_conn[idx].connection.c_index, sctp_conn->ack_state);
      return 0;
    }

  sctp_conn->ack_state += 1;
  if (sctp_conn->ack_state >= MAX_ENQUEABLE_SACKS)
    {
      SCTP_CONN_TRACKING_DBG
        ("sctp_conn->ack_state >= MAX_ENQUEABLE_SACKS: CONN_INDEX = %u, sctp_conn->ack_state = %u",
         sctp_conn->sub_conn[idx].connection.c_index, sctp_conn->ack_state);
      return 0;
    }

  return 1;
}

always_inline void
sctp_is_connection_gapping (sctp_connection_t * sctp_conn, u32 tsn,
                            u8 * gapping)
{
  if (sctp_conn->next_tsn_expected != tsn)      // It means data transmission is GAPPING
    {
      SCTP_CONN_TRACKING_DBG
        ("GAPPING: CONN_INDEX = %u, sctp_conn->next_tsn_expected = %u, tsn = %u, diff = %u",
         sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.c_index,
         sctp_conn->next_tsn_expected, tsn,
         sctp_conn->next_tsn_expected - tsn);

      *gapping = 1;
    }
}

always_inline u16
sctp_handle_data (sctp_payload_data_chunk_t * sctp_data_chunk,
                  sctp_connection_t * sctp_conn, u8 idx, vlib_buffer_t * b,
                  u16 * next0)
{
  u32 error = 0, n_data_bytes;
  u8 is_gapping = 0;

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_data_chunk->sctp_hdr.verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      sctp_conn->sub_conn[idx].enqueue_state = SCTP_ERROR_INVALID_TAG;
      return sctp_conn->sub_conn[idx].enqueue_state;
    }

  vnet_buffer (b)->sctp.sid = sctp_data_chunk->stream_id;
  vnet_buffer (b)->sctp.ssn = sctp_data_chunk->stream_seq;

  u32 tsn = clib_net_to_host_u32 (sctp_data_chunk->tsn);

  vlib_buffer_advance (b, vnet_buffer (b)->sctp.data_offset);
  u32 chunk_len = vnet_sctp_get_chunk_length (&sctp_data_chunk->chunk_hdr) -
    (sizeof (sctp_payload_data_chunk_t) - sizeof (sctp_header_t));

  ASSERT (vnet_buffer (b)->sctp.data_len);
  ASSERT (chunk_len);

  /* Padding was added: see RFC 4096 section 3.3.1 */
  if (vnet_buffer (b)->sctp.data_len > chunk_len)
    {
      /* Let's change the data_len to the right amount calculated here now.
       * We cannot do that in the generic sctp46_input_dispatcher node since
       * that is common to all CHUNKS handling.
       */
      vnet_buffer (b)->sctp.data_len = chunk_len;
      /* We need to change b->current_length so that downstream calls to
       * session_enqueue_stream_connection (called by sctp_session_enqueue_data)
       * push the correct amount of data to be enqueued.
       */
      b->current_length = chunk_len;
    }
  n_data_bytes = vnet_buffer (b)->sctp.data_len;

  sctp_is_connection_gapping (sctp_conn, tsn, &is_gapping);

  sctp_conn->last_rcvd_tsn = tsn;

  SCTP_ADV_DBG ("POINTER_WITH_DATA = %p", b->data);

  u8 bbit = vnet_sctp_get_bbit (&sctp_data_chunk->chunk_hdr);
  u8 ebit = vnet_sctp_get_ebit (&sctp_data_chunk->chunk_hdr);

  if (bbit == 1 && ebit == 1)   /* Unfragmented message */
    {
      /* In order data, enqueue. Fifo figures out by itself if any out-of-order
       * segments can be enqueued after fifo tail offset changes. */
      if (PREDICT_FALSE (is_gapping == 1))
        error =
          sctp_session_enqueue_data_ooo (sctp_conn, b, n_data_bytes, idx);
      else
        error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
    }
  else if (bbit == 1 && ebit == 0)      /* First piece of a fragmented user message */
    {
      error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
    }
  else if (bbit == 0 && ebit == 1)      /* Last piece of a fragmented user message */
    {
      if (PREDICT_FALSE (is_gapping == 1))
        error =
          sctp_session_enqueue_data_ooo (sctp_conn, b, n_data_bytes, idx);
      else
        error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
    }
  else                          /* Middle piece of a fragmented user message */
    {
      if (PREDICT_FALSE (is_gapping == 1))
        error =
          sctp_session_enqueue_data_ooo (sctp_conn, b, n_data_bytes, idx);
      else
        error = sctp_session_enqueue_data (sctp_conn, b, n_data_bytes, idx);
    }
  sctp_conn->last_rcvd_tsn = tsn;

  SCTP_ADV_DBG ("POINTER_WITH_DATA = %p", b->data);

  if (!sctp_is_sack_delayable (sctp_conn, idx, is_gapping))
    {
      *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);
      sctp_prepare_sack_chunk (sctp_conn, idx, b);
    }
  else
    *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);

  sctp_conn->sub_conn[idx].enqueue_state = error;

  return error;
}

always_inline u16
sctp_handle_cookie_echo (sctp_header_t * sctp_hdr,
                         sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                         sctp_connection_t * sctp_conn, u8 idx,
                         vlib_buffer_t * b0, u16 * next0)
{
  u64 now = sctp_time_now ();

  sctp_cookie_echo_chunk_t *cookie_echo =
    (sctp_cookie_echo_chunk_t *) sctp_hdr;

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      return SCTP_ERROR_INVALID_TAG;
    }

  sctp_calculate_rto (sctp_conn, idx);

  u64 creation_time =
    clib_net_to_host_u64 (cookie_echo->cookie.creation_time);
  u64 cookie_lifespan =
    clib_net_to_host_u32 (cookie_echo->cookie.cookie_lifespan);

  if (now > creation_time + cookie_lifespan)
    {
      SCTP_DBG ("now (%u) > creation_time (%u) + cookie_lifespan (%u)",
                now, creation_time, cookie_lifespan);
      return SCTP_ERROR_COOKIE_ECHO_VIOLATION;
    }

  sctp_prepare_cookie_ack_chunk (sctp_conn, idx, b0);

  /* Change state */
  sctp_conn->state = SCTP_STATE_ESTABLISHED;
  sctp_conn->sub_conn[idx].state = SCTP_SUBCONN_STATE_UP;
  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);

  sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T4_HEARTBEAT,
                  sctp_conn->sub_conn[idx].RTO);

  stream_session_accept_notify (&sctp_conn->sub_conn[idx].connection);

  return SCTP_ERROR_NONE;

}

always_inline u16
sctp_handle_cookie_ack (sctp_header_t * sctp_hdr,
                        sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                        sctp_connection_t * sctp_conn, u8 idx,
                        vlib_buffer_t * b0, u16 * next0)
{
  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      return SCTP_ERROR_INVALID_TAG;
    }

  sctp_calculate_rto (sctp_conn, idx);

  sctp_timer_reset (sctp_conn, idx, SCTP_TIMER_T1_COOKIE);
  /* Change state */
  sctp_conn->state = SCTP_STATE_ESTABLISHED;
  sctp_conn->sub_conn[idx].state = SCTP_SUBCONN_STATE_UP;

  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);

  sctp_timer_set (sctp_conn, idx, SCTP_TIMER_T4_HEARTBEAT,
                  sctp_conn->sub_conn[idx].RTO);

  stream_session_accept_notify (&sctp_conn->sub_conn[idx].connection);

  return SCTP_ERROR_NONE;

}

always_inline uword
sctp46_rcv_phase_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
                         vlib_frame_t * from_frame, int is_ip4)
{
  sctp_main_t *tm = vnet_get_sctp_main ();

  u32 n_left_from, next_index, *from, *to_next;
  u32 my_thread_index = vm->thread_index;

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

  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

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

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          sctp_header_t *sctp_hdr = 0;
          sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
          ip4_header_t *ip4_hdr = 0;
          ip6_header_t *ip6_hdr = 0;
          sctp_connection_t *sctp_conn, *new_sctp_conn;
          u16 sctp_implied_length = 0;
          u16 error0 = SCTP_ERROR_NONE, next0 = sctp_next_drop (is_ip4);
          u8 idx;

          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);

          /* If we are in SCTP_COOKIE_WAIT_STATE then the connection
           * will come from the half-open connections pool.
           */
          sctp_conn =
            sctp_half_open_connection_get (vnet_buffer (b0)->
                                           sctp.connection_index);

          if (PREDICT_FALSE (sctp_conn == 0))
            {
              SCTP_ADV_DBG
                ("sctp_conn == NULL; return SCTP_ERROR_INVALID_CONNECTION");
              error0 = SCTP_ERROR_INVALID_CONNECTION;
              goto drop;
            }
          if (is_ip4)
            {
              ip4_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip4_next_header (ip4_hdr);
              idx = sctp_sub_conn_id_via_ip4h (sctp_conn, ip4_hdr);
            }
          else
            {
              ip6_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip6_next_header (ip6_hdr);
              idx = sctp_sub_conn_id_via_ip6h (sctp_conn, ip6_hdr);
            }

          sctp_conn->sub_conn[idx].subconn_idx = idx;
          sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;

          sctp_chunk_hdr =
            (sctp_chunks_common_hdr_t *) (&full_hdr->common_hdr);

          sctp_implied_length =
            sctp_calculate_implied_length (ip4_hdr, ip6_hdr, is_ip4);

          u8 chunk_type = vnet_sctp_get_chunk_type (&full_hdr->common_hdr);

          switch (chunk_type)
            {
            case INIT_ACK:
              error0 =
                sctp_is_valid_init_ack (sctp_hdr, sctp_chunk_hdr, sctp_conn,
                                        b0, sctp_implied_length);

              if (error0 == SCTP_ERROR_NONE)
                {
                  pool_get (tm->connections[my_thread_index], new_sctp_conn);
                  clib_memcpy_fast (new_sctp_conn, sctp_conn,
                                    sizeof (*new_sctp_conn));
                  new_sctp_conn->sub_conn[idx].c_c_index =
                    new_sctp_conn - tm->connections[my_thread_index];
                  new_sctp_conn->sub_conn[idx].c_thread_index =
                    my_thread_index;
                  new_sctp_conn->sub_conn[idx].PMTU =
                    sctp_conn->sub_conn[idx].PMTU;
                  new_sctp_conn->sub_conn[idx].subconn_idx = idx;

                  if (sctp_half_open_connection_cleanup (sctp_conn))
                    {
                      SCTP_DBG
                        ("Cannot cleanup half-open connection; not the owning thread");
                    }

                  sctp_connection_timers_init (new_sctp_conn);

                  sctp_init_cwnd (new_sctp_conn);

                  error0 =
                    sctp_handle_init_ack (sctp_hdr, sctp_chunk_hdr,
                                          new_sctp_conn, idx, b0,
                                          sctp_implied_length);

                  if (session_stream_connect_notify
                      (&new_sctp_conn->sub_conn[idx].connection, 0))
                    {
                      SCTP_DBG
                        ("conn_index = %u: session_stream_connect_notify error; cleaning up connection",
                         new_sctp_conn->sub_conn[idx].connection.c_index);
                      sctp_connection_cleanup (new_sctp_conn);
                      goto drop;
                    }
                  next0 = sctp_next_output (is_ip4);
                }
              break;

            case OPERATION_ERROR:
              error0 =
                sctp_handle_operation_err (sctp_hdr, sctp_conn, idx, b0,
                                           &next0);
              break;

              /* All UNEXPECTED scenarios (wrong chunk received per state-machine)
               * are handled by the input-dispatcher function using the table-lookup
               * hence we should never get to the "default" case below.
               */
            default:
              error0 = SCTP_ERROR_UNKNOWN_CHUNK;
              next0 = sctp_next_drop (is_ip4);
              goto drop;
            }

          if (error0 != SCTP_ERROR_NONE)
            {
              clib_warning ("error while parsing chunk");
              sctp_connection_cleanup (sctp_conn);
              next0 = sctp_next_drop (is_ip4);
              goto drop;
            }

        drop:
          b0->error = node->errors[error0];
          if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              sctp_rx_trace_t *t0 =
                vlib_add_trace (vm, node, b0, sizeof (*t0));
              sctp_set_rx_trace_data (t0, sctp_conn, sctp_hdr, b0, is_ip4);
            }

          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 from_frame->n_vectors;
}

static uword
sctp4_rcv_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                 vlib_frame_t * from_frame)
{
  return sctp46_rcv_phase_inline (vm, node, from_frame, 1 /* is_ip4 */ );
}

static uword
sctp6_rcv_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                 vlib_frame_t * from_frame)
{
  return sctp46_rcv_phase_inline (vm, node, from_frame, 0 /* is_ip4 */ );
}

u8 *
format_sctp_rx_trace_short (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 *);
  sctp_rx_trace_t *t = va_arg (*args, sctp_rx_trace_t *);

  s = format (s, "%d -> %d (%U)",
              clib_net_to_host_u16 (t->sctp_header.src_port),
              clib_net_to_host_u16 (t->sctp_header.dst_port),
              format_sctp_state, t->sctp_connection.state);

  return s;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp4_rcv_phase_node) =
{
  .function = sctp4_rcv_phase,
  .name = "sctp4-rcv",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_RCV_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_RCV_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp4_rcv_phase_node, sctp4_rcv_phase);

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp6_init_phase_node) =
{
  .function = sctp6_rcv_phase,
  .name = "sctp6-rcv",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_RCV_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_RCV_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp6_init_phase_node, sctp6_rcv_phase);

vlib_node_registration_t sctp4_shutdown_phase_node;
vlib_node_registration_t sctp6_shutdown_phase_node;

always_inline u16
sctp_handle_shutdown (sctp_header_t * sctp_hdr,
                      sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                      sctp_connection_t * sctp_conn, u8 idx,
                      vlib_buffer_t * b0, u16 sctp_implied_length,
                      u16 * next0)
{
  sctp_shutdown_association_chunk_t *shutdown_chunk =
    (sctp_shutdown_association_chunk_t *) (sctp_hdr);

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      return SCTP_ERROR_INVALID_TAG;
    }

  /*
   * It is not possible to bundle any other CHUNK with the SHUTDOWN chunk
   */
  if (sctp_is_bundling (sctp_implied_length, &shutdown_chunk->chunk_hdr))
    return SCTP_ERROR_BUNDLING_VIOLATION;

  switch (sctp_conn->state)
    {
    case SCTP_STATE_ESTABLISHED:
      if (sctp_check_outstanding_data_chunks (sctp_conn) == 0)
        sctp_conn->state = SCTP_STATE_SHUTDOWN_RECEIVED;
      sctp_send_shutdown_ack (sctp_conn, idx, b0);
      break;

    case SCTP_STATE_SHUTDOWN_SENT:
      sctp_send_shutdown_ack (sctp_conn, idx, b0);
      break;
    }

  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);

  return SCTP_ERROR_NONE;
}

always_inline u16
sctp_handle_shutdown_ack (sctp_header_t * sctp_hdr,
                          sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                          sctp_connection_t * sctp_conn, u8 idx,
                          vlib_buffer_t * b0, u16 sctp_implied_length,
                          u16 * next0)
{
  sctp_shutdown_ack_chunk_t *shutdown_ack_chunk =
    (sctp_shutdown_ack_chunk_t *) (sctp_hdr);

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      return SCTP_ERROR_INVALID_TAG;
    }

  /*
   * It is not possible to bundle any other CHUNK with the SHUTDOWN chunk
   */
  if (sctp_is_bundling (sctp_implied_length, &shutdown_ack_chunk->chunk_hdr))
    return SCTP_ERROR_BUNDLING_VIOLATION;

  /* Whether we are in SCTP_STATE_SHUTDOWN_SENT or SCTP_STATE_SHUTDOWN_ACK_SENT
   * the reception of a SHUTDOWN_ACK chunk leads to the same actions:
   * - STOP T2_SHUTDOWN timer
   * - SEND SHUTDOWN_COMPLETE chunk
   */
  sctp_timer_reset (sctp_conn, SCTP_PRIMARY_PATH_IDX, SCTP_TIMER_T2_SHUTDOWN);

  sctp_send_shutdown_complete (sctp_conn, idx, b0);

  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].c_is_ip4);

  return SCTP_ERROR_NONE;
}

always_inline u16
sctp_handle_shutdown_complete (sctp_header_t * sctp_hdr,
                               sctp_chunks_common_hdr_t * sctp_chunk_hdr,
                               sctp_connection_t * sctp_conn, u8 idx,
                               vlib_buffer_t * b0, u16 sctp_implied_length,
                               u16 * next0)
{
  sctp_shutdown_complete_chunk_t *shutdown_complete =
    (sctp_shutdown_complete_chunk_t *) (sctp_hdr);

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_hdr->verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      return SCTP_ERROR_INVALID_TAG;
    }

  /*
   * It is not possible to bundle any other CHUNK with the SHUTDOWN chunk
   */
  if (sctp_is_bundling (sctp_implied_length, &shutdown_complete->chunk_hdr))
    return SCTP_ERROR_BUNDLING_VIOLATION;

  sctp_timer_reset (sctp_conn, idx, SCTP_TIMER_T2_SHUTDOWN);

  session_transport_closing_notify (&sctp_conn->sub_conn[idx].connection);

  sctp_conn->state = SCTP_STATE_CLOSED;

  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);

  return SCTP_ERROR_NONE;
}

always_inline uword
sctp46_shutdown_phase_inline (vlib_main_t * vm,
                              vlib_node_runtime_t * node,
                              vlib_frame_t * from_frame, int is_ip4)
{
  u32 n_left_from, next_index, *from, *to_next;
  u32 my_thread_index = vm->thread_index;

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

  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

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

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          sctp_rx_trace_t *sctp_trace;
          sctp_header_t *sctp_hdr = 0;
          sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
          ip4_header_t *ip4_hdr = 0;
          ip6_header_t *ip6_hdr = 0;
          sctp_connection_t *sctp_conn;
          u16 sctp_implied_length = 0;
          u16 error0 = SCTP_ERROR_NONE, next0 = SCTP_RCV_PHASE_N_NEXT;
          u8 idx = 0;

          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);
          sctp_conn =
            sctp_connection_get (vnet_buffer (b0)->sctp.connection_index,
                                 my_thread_index);

          if (PREDICT_FALSE (sctp_conn == 0))
            {
              SCTP_DBG
                ("sctp_conn == NULL; return SCTP_ERROR_INVALID_CONNECTION");
              error0 = SCTP_ERROR_INVALID_CONNECTION;
              goto drop;
            }

          if (is_ip4)
            {
              ip4_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip4_next_header (ip4_hdr);
              idx = sctp_sub_conn_id_via_ip4h (sctp_conn, ip4_hdr);
            }
          else
            {
              ip6_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip6_next_header (ip6_hdr);
              idx = sctp_sub_conn_id_via_ip6h (sctp_conn, ip6_hdr);
            }

          sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
          sctp_chunk_hdr = &full_hdr->common_hdr;

          sctp_implied_length =
            sctp_calculate_implied_length (ip4_hdr, ip6_hdr, is_ip4);

          u8 chunk_type = vnet_sctp_get_chunk_type (sctp_chunk_hdr);
          switch (chunk_type)
            {
            case SHUTDOWN:
              error0 =
                sctp_handle_shutdown (sctp_hdr, sctp_chunk_hdr, sctp_conn,
                                      idx, b0, sctp_implied_length, &next0);
              break;

            case SHUTDOWN_ACK:
              error0 =
                sctp_handle_shutdown_ack (sctp_hdr, sctp_chunk_hdr, sctp_conn,
                                          idx, b0, sctp_implied_length,
                                          &next0);
              break;

            case SHUTDOWN_COMPLETE:
              error0 =
                sctp_handle_shutdown_complete (sctp_hdr, sctp_chunk_hdr,
                                               sctp_conn, idx, b0,
                                               sctp_implied_length, &next0);

              sctp_connection_cleanup (sctp_conn);
              break;

              /*
               * DATA chunks can still be transmitted/received in the SHUTDOWN-PENDING
               * and SHUTDOWN-SENT states (as per RFC4960 Section 6)
               */
            case DATA:
              error0 =
                sctp_handle_data ((sctp_payload_data_chunk_t *) sctp_hdr,
                                  sctp_conn, idx, b0, &next0);
              break;

            case OPERATION_ERROR:
              error0 =
                sctp_handle_operation_err (sctp_hdr, sctp_conn, idx, b0,
                                           &next0);
              break;

            case COOKIE_ECHO:   /* Cookie Received While Shutting Down */
              sctp_prepare_operation_error (sctp_conn, idx, b0,
                                            COOKIE_RECEIVED_WHILE_SHUTTING_DOWN);
              error0 = SCTP_ERROR_NONE;
              next0 = sctp_next_output (is_ip4);
              break;
              /* All UNEXPECTED scenarios (wrong chunk received per state-machine)
               * are handled by the input-dispatcher function using the table-lookup
               * hence we should never get to the "default" case below.
               */
            default:
              error0 = SCTP_ERROR_UNKNOWN_CHUNK;
              next0 = sctp_next_drop (is_ip4);
              goto drop;
            }

          if (error0 != SCTP_ERROR_NONE)
            {
              clib_warning ("error while parsing chunk");
              sctp_connection_cleanup (sctp_conn);
              next0 = sctp_next_drop (is_ip4);
              goto drop;
            }

        drop:
          if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              sctp_trace =
                vlib_add_trace (vm, node, b0, sizeof (*sctp_trace));

              if (sctp_hdr != NULL)
                clib_memcpy_fast (&sctp_trace->sctp_header, sctp_hdr,
                                  sizeof (sctp_trace->sctp_header));

              if (sctp_conn != NULL)
                clib_memcpy_fast (&sctp_trace->sctp_connection, sctp_conn,
                                  sizeof (sctp_trace->sctp_connection));
            }

          b0->error = node->errors[error0];

          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 from_frame->n_vectors;

}

static uword
sctp4_shutdown_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                      vlib_frame_t * from_frame)
{
  return sctp46_shutdown_phase_inline (vm, node, from_frame, 1 /* is_ip4 */ );
}

static uword
sctp6_shutdown_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                      vlib_frame_t * from_frame)
{
  return sctp46_shutdown_phase_inline (vm, node, from_frame, 1 /* is_ip4 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp4_shutdown_phase_node) =
{
  .function = sctp4_shutdown_phase,
  .name = "sctp4-shutdown",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_SHUTDOWN_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_SHUTDOWN_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp4_shutdown_phase_node,
                              sctp4_shutdown_phase);

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp6_shutdown_phase_node) =
{
  .function = sctp6_shutdown_phase,
  .name = "sctp6-shutdown",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_SHUTDOWN_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_SHUTDOWN_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp6_shutdown_phase_node,
                              sctp6_shutdown_phase);

vlib_node_registration_t sctp4_listen_phase_node;
vlib_node_registration_t sctp6_listen_phase_node;

vlib_node_registration_t sctp4_established_phase_node;
vlib_node_registration_t sctp6_established_phase_node;

always_inline u16
sctp_handle_sack (sctp_selective_ack_chunk_t * sack_chunk,
                  sctp_connection_t * sctp_conn, u8 idx, vlib_buffer_t * b0,
                  u16 * next0)
{

  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sack_chunk->sctp_hdr.verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      return SCTP_ERROR_INVALID_TAG;
    }

  sctp_conn->sub_conn[idx].state = SCTP_SUBCONN_SACK_RECEIVED;

  sctp_conn->sub_conn[idx].last_seen = sctp_time_now ();

  /* Section 7.2.2; point (2) */
  if (sctp_conn->sub_conn[idx].cwnd > sctp_conn->sub_conn[idx].ssthresh)
    sctp_conn->sub_conn[idx].partially_acked_bytes =
      sctp_conn->next_tsn - sack_chunk->cumulative_tsn_ack;

  /* Section 7.2.2; point (5) */
  if (sctp_conn->next_tsn - sack_chunk->cumulative_tsn_ack == 0)
    sctp_conn->sub_conn[idx].partially_acked_bytes = 0;

  sctp_conn->last_unacked_tsn = sack_chunk->cumulative_tsn_ack;

  sctp_calculate_rto (sctp_conn, idx);

  sctp_timer_update (sctp_conn, idx, SCTP_TIMER_T3_RXTX,
                     sctp_conn->sub_conn[idx].RTO);

  sctp_conn->sub_conn[idx].RTO_pending = 0;

  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);

  return SCTP_ERROR_NONE;
}

always_inline u16
sctp_handle_heartbeat (sctp_hb_req_chunk_t * sctp_hb_chunk,
                       sctp_connection_t * sctp_conn, u8 idx,
                       vlib_buffer_t * b0, u16 * next0)
{
  /* Check that the LOCALLY generated tag is being used by the REMOTE peer as the verification tag */
  if (sctp_conn->local_tag != sctp_hb_chunk->sctp_hdr.verification_tag)
    {
      *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);
      return SCTP_ERROR_INVALID_TAG;
    }

  sctp_prepare_heartbeat_ack_chunk (sctp_conn, idx, b0);

  *next0 = sctp_next_output (sctp_conn->sub_conn[idx].connection.is_ip4);

  return SCTP_ERROR_NONE;
}

always_inline u16
sctp_handle_heartbeat_ack (sctp_hb_ack_chunk_t * sctp_hb_ack_chunk,
                           sctp_connection_t * sctp_conn, u8 idx,
                           vlib_buffer_t * b0, u16 * next0)
{
  sctp_conn->sub_conn[idx].last_seen = sctp_time_now ();

  sctp_conn->sub_conn[idx].unacknowledged_hb -= 1;

  sctp_timer_update (sctp_conn, idx, SCTP_TIMER_T4_HEARTBEAT,
                     sctp_conn->sub_conn[idx].RTO);

  *next0 = sctp_next_drop (sctp_conn->sub_conn[idx].c_is_ip4);

  return SCTP_ERROR_NONE;
}

always_inline void
sctp_node_inc_counter (vlib_main_t * vm, u32 sctp4_node, u32 sctp6_node,
                       u8 is_ip4, u8 evt, u8 val)
{
  if (PREDICT_TRUE (!val))
    return;

  if (is_ip4)
    vlib_node_increment_counter (vm, sctp4_node, evt, val);
  else
    vlib_node_increment_counter (vm, sctp6_node, evt, val);
}

always_inline uword
sctp46_listen_process_inline (vlib_main_t * vm,
                              vlib_node_runtime_t * node,
                              vlib_frame_t * from_frame, int is_ip4)
{
  u32 n_left_from, next_index, *from, *to_next;
  u32 my_thread_index = vm->thread_index;

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

  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

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

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          sctp_header_t *sctp_hdr = 0;
          ip4_header_t *ip4_hdr;
          ip6_header_t *ip6_hdr;
          sctp_connection_t *child_conn;
          sctp_connection_t *sctp_listener;
          u16 next0 = sctp_next_drop (is_ip4), error0 = SCTP_ERROR_ENQUEUED;

          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);
          sctp_listener =
            sctp_listener_get (vnet_buffer (b0)->sctp.connection_index);

          if (is_ip4)
            {
              ip4_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip4_next_header (ip4_hdr);
            }
          else
            {
              ip6_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip6_next_header (ip6_hdr);
            }

          child_conn =
            sctp_lookup_connection (sctp_listener->sub_conn
                                    [SCTP_PRIMARY_PATH_IDX].c_fib_index, b0,
                                    my_thread_index, is_ip4);

          if (PREDICT_FALSE (child_conn->state != SCTP_STATE_CLOSED))
            {
              SCTP_DBG
                ("conn_index = %u: child_conn->state != SCTP_STATE_CLOSED.... STATE=%s",
                 child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
                 connection.c_index,
                 sctp_state_to_string (child_conn->state));
              error0 = SCTP_ERROR_CREATE_EXISTS;
              goto drop;
            }

          /* Create child session and send SYN-ACK */
          child_conn = sctp_connection_new (my_thread_index);
          child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].subconn_idx =
            SCTP_PRIMARY_PATH_IDX;
          child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_lcl_port =
            sctp_hdr->dst_port;
          child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_rmt_port =
            sctp_hdr->src_port;
          child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_is_ip4 = is_ip4;
          child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.proto =
            sctp_listener->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.proto;
          child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].PMTU =
            sctp_listener->sub_conn[SCTP_PRIMARY_PATH_IDX].PMTU;
          child_conn->state = SCTP_STATE_CLOSED;
          child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].connection.fib_index =
            sctp_listener->sub_conn[SCTP_PRIMARY_PATH_IDX].
            connection.fib_index;

          if (is_ip4)
            {
              child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_lcl_ip4.as_u32 =
                ip4_hdr->dst_address.as_u32;
              child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].c_rmt_ip4.as_u32 =
                ip4_hdr->src_address.as_u32;
            }
          else
            {
              clib_memcpy_fast (&child_conn->
                                sub_conn[SCTP_PRIMARY_PATH_IDX].c_lcl_ip6,
                                &ip6_hdr->dst_address,
                                sizeof (ip6_address_t));
              clib_memcpy_fast (&child_conn->
                                sub_conn[SCTP_PRIMARY_PATH_IDX].c_rmt_ip6,
                                &ip6_hdr->src_address,
                                sizeof (ip6_address_t));
            }

          sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
          sctp_chunks_common_hdr_t *sctp_chunk_hdr = &full_hdr->common_hdr;

          u8 chunk_type = vnet_sctp_get_chunk_type (sctp_chunk_hdr);
          if (chunk_type != INIT && chunk_type != DATA
              && chunk_type != OPERATION_ERROR)
            {
              SCTP_DBG
                ("conn_index = %u: chunk_type != INIT... chunk_type=%s",
                 child_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
                 connection.c_index, sctp_chunk_to_string (chunk_type));

              error0 = SCTP_ERROR_UNKNOWN_CHUNK;
              next0 = sctp_next_drop (is_ip4);
              goto drop;
            }

          u16 sctp_implied_length =
            sctp_calculate_implied_length (ip4_hdr, ip6_hdr, is_ip4);

          switch (chunk_type)
            {
            case INIT:
              sctp_connection_timers_init (child_conn);

              sctp_init_snd_vars (child_conn);

              sctp_init_cwnd (child_conn);

              error0 =
                sctp_handle_init (sctp_hdr, sctp_chunk_hdr, child_conn, b0,
                                  sctp_implied_length);

              if (error0 == SCTP_ERROR_NONE)
                {
                  if (stream_session_accept
                      (&child_conn->
                       sub_conn[SCTP_PRIMARY_PATH_IDX].connection,
                       sctp_listener->
                       sub_conn[SCTP_PRIMARY_PATH_IDX].c_s_index, 0))
                    {
                      clib_warning ("session accept fail");
                      sctp_connection_cleanup (child_conn);
                      error0 = SCTP_ERROR_CREATE_SESSION_FAIL;
                      goto drop;
                    }
                  next0 = sctp_next_output (is_ip4);
                }
              break;

              /* Reception of a DATA chunk whilst in the CLOSED state is called
               * "Out of the Blue" packet and handling of the chunk needs special treatment
               * as per RFC4960 section 8.4
               */
            case DATA:
              break;

            case OPERATION_ERROR:
              error0 =
                sctp_handle_operation_err (sctp_hdr, child_conn,
                                           SCTP_PRIMARY_PATH_IDX, b0, &next0);
              break;
            }

        drop:
          if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              sctp_rx_trace_t *t0 =
                vlib_add_trace (vm, node, b0, sizeof (*t0));
              clib_memcpy_fast (&t0->sctp_header, sctp_hdr,
                                sizeof (t0->sctp_header));
              clib_memcpy_fast (&t0->sctp_connection, sctp_listener,
                                sizeof (t0->sctp_connection));
            }

          b0->error = node->errors[error0];

          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 from_frame->n_vectors;
}

static uword
sctp4_listen_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                    vlib_frame_t * from_frame)
{
  return sctp46_listen_process_inline (vm, node, from_frame, 1 /* is_ip4 */ );
}

static uword
sctp6_listen_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                    vlib_frame_t * from_frame)
{
  return sctp46_listen_process_inline (vm, node, from_frame, 0 /* is_ip4 */ );
}

always_inline uword
sctp46_established_phase_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
                                 vlib_frame_t * from_frame, int is_ip4)
{
  u32 n_left_from, next_index, *from, *to_next;
  u32 my_thread_index = vm->thread_index, errors = 0;

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

  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

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

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          u32 bi0;
          vlib_buffer_t *b0;
          sctp_header_t *sctp_hdr = 0;
          sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
          ip4_header_t *ip4_hdr = 0;
          ip6_header_t *ip6_hdr = 0;
          sctp_connection_t *sctp_conn;
          u16 error0 = SCTP_ERROR_ENQUEUED, next0 =
            SCTP_ESTABLISHED_PHASE_N_NEXT;
          u8 idx;

          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);
          sctp_conn =
            sctp_connection_get (vnet_buffer (b0)->sctp.connection_index,
                                 my_thread_index);

          if (PREDICT_FALSE (sctp_conn == 0))
            {
              SCTP_DBG
                ("sctp_conn == NULL; return SCTP_ERROR_INVALID_CONNECTION");
              error0 = SCTP_ERROR_INVALID_CONNECTION;
              goto done;
            }
          if (is_ip4)
            {
              ip4_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip4_next_header (ip4_hdr);
              idx = sctp_sub_conn_id_via_ip4h (sctp_conn, ip4_hdr);
            }
          else
            {
              ip6_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip6_next_header (ip6_hdr);
              idx = sctp_sub_conn_id_via_ip6h (sctp_conn, ip6_hdr);
            }

          sctp_conn->sub_conn[idx].subconn_idx = idx;

          sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
          sctp_chunk_hdr =
            (sctp_chunks_common_hdr_t *) (&full_hdr->common_hdr);

          u8 chunk_type = vnet_sctp_get_chunk_type (&full_hdr->common_hdr);

          switch (chunk_type)
            {
            case COOKIE_ECHO:
              error0 =
                sctp_handle_cookie_echo (sctp_hdr, sctp_chunk_hdr, sctp_conn,
                                         idx, b0, &next0);
              break;

            case COOKIE_ACK:
              error0 =
                sctp_handle_cookie_ack (sctp_hdr, sctp_chunk_hdr, sctp_conn,
                                        idx, b0, &next0);
              break;

            case SACK:
              error0 =
                sctp_handle_sack ((sctp_selective_ack_chunk_t *) sctp_hdr,
                                  sctp_conn, idx, b0, &next0);
              break;

            case HEARTBEAT:
              error0 =
                sctp_handle_heartbeat ((sctp_hb_req_chunk_t *) sctp_hdr,
                                       sctp_conn, idx, b0, &next0);
              break;

            case HEARTBEAT_ACK:
              error0 =
                sctp_handle_heartbeat_ack ((sctp_hb_ack_chunk_t *) sctp_hdr,
                                           sctp_conn, idx, b0, &next0);
              break;

            case DATA:
              error0 =
                sctp_handle_data ((sctp_payload_data_chunk_t *) sctp_hdr,
                                  sctp_conn, idx, b0, &next0);
              break;

            case OPERATION_ERROR:
              error0 =
                sctp_handle_operation_err (sctp_hdr, sctp_conn, idx, b0,
                                           &next0);
              break;

              /* All UNEXPECTED scenarios (wrong chunk received per state-machine)
               * are handled by the input-dispatcher function using the table-lookup
               * hence we should never get to the "default" case below.
               */
            default:
              error0 = SCTP_ERROR_UNKNOWN_CHUNK;
              next0 = sctp_next_drop (is_ip4);
              goto done;
            }

        done:
          b0->error = node->errors[error0];
          if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              sctp_rx_trace_t *t0 =
                vlib_add_trace (vm, node, b0, sizeof (*t0));
              sctp_set_rx_trace_data (t0, sctp_conn, sctp_hdr, b0, is_ip4);
            }

          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);
    }

  errors = session_manager_flush_enqueue_events (TRANSPORT_PROTO_SCTP,
                                                 my_thread_index);

  sctp_node_inc_counter (vm, is_ip4, sctp4_established_phase_node.index,
                         sctp6_established_phase_node.index,
                         SCTP_ERROR_EVENT_FIFO_FULL, errors);
  sctp_flush_frame_to_output (vm, my_thread_index, is_ip4);

  return from_frame->n_vectors;
}

static uword
sctp4_established_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                         vlib_frame_t * from_frame)
{
  return sctp46_established_phase_inline (vm, node, from_frame,
                                          1 /* is_ip4 */ );
}

static uword
sctp6_established_phase (vlib_main_t * vm, vlib_node_runtime_t * node,
                         vlib_frame_t * from_frame)
{
  return sctp46_established_phase_inline (vm, node, from_frame,
                                          0 /* is_ip4 */ );
}

u8 *
format_sctp_rx_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 *);
  sctp_rx_trace_t *t = va_arg (*args, sctp_rx_trace_t *);
  u32 indent = format_get_indent (s);

  s = format (s, "%U\n%U%U",
              format_sctp_header, &t->sctp_header, 128,
              format_white_space, indent,
              format_sctp_connection, &t->sctp_connection, 1);

  return s;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp4_listen_phase_node) =
{
  .function = sctp4_listen_phase,
  .name = "sctp4-listen",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_LISTEN_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_LISTEN_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp4_listen_phase_node, sctp4_listen_phase);

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp6_listen_phase_node) =
{
  .function = sctp6_listen_phase,
  .name = "sctp6-listen",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_LISTEN_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_LISTEN_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp6_listen_phase_node, sctp6_listen_phase);

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp4_established_phase_node) =
{
  .function = sctp4_established_phase,
  .name = "sctp4-established",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_ESTABLISHED_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_ESTABLISHED_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp4_established_phase_node,
                              sctp4_established_phase);

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp6_established_phase_node) =
{
  .function = sctp6_established_phase,
  .name = "sctp6-established",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_LISTEN_PHASE_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_LISTEN_PHASE_NEXT_##s] = n,
    foreach_sctp_state_next
#undef _
  },
  .format_trace = format_sctp_rx_trace_short,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp6_established_phase_node,
                              sctp6_established_phase);

/*
 * This is the function executed first for the SCTP graph.
 * It takes care of doing the initial message parsing and
 * dispatch to the specialized function.
 */
always_inline uword
sctp46_input_dispatcher (vlib_main_t * vm, vlib_node_runtime_t * node,
                         vlib_frame_t * from_frame, int is_ip4)
{
  u32 n_left_from, next_index, *from, *to_next;
  u32 my_thread_index = vm->thread_index;
  u8 result;
  sctp_main_t *tm = vnet_get_sctp_main ();

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;
  next_index = node->cached_next_index;
  sctp_set_time_now (my_thread_index);

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

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

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          int n_advance_bytes0, n_data_bytes0;
          u32 bi0, fib_index0;
          vlib_buffer_t *b0;
          sctp_header_t *sctp_hdr = 0;
          sctp_chunks_common_hdr_t *sctp_chunk_hdr = 0;
          sctp_connection_t *sctp_conn;
          transport_connection_t *trans_conn;
          ip4_header_t *ip4_hdr;
          ip6_header_t *ip6_hdr;
          u32 error0 = SCTP_ERROR_NO_LISTENER, next0 = SCTP_INPUT_NEXT_DROP;

          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);
          vnet_buffer (b0)->sctp.flags = 0;
          fib_index0 = vnet_buffer (b0)->ip.fib_index;

          /* Checksum computed by ipx_local no need to compute again */

          if (is_ip4)
            {
              ip4_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip4_next_header (ip4_hdr);

              sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
              sctp_chunk_hdr = &full_hdr->common_hdr;

              n_advance_bytes0 =
                (ip4_header_bytes (ip4_hdr) +
                 sizeof (sctp_payload_data_chunk_t));
              n_data_bytes0 =
                clib_net_to_host_u16 (ip4_hdr->length) - n_advance_bytes0;

              trans_conn = session_lookup_connection_wt4 (fib_index0,
                                                          &ip4_hdr->dst_address,
                                                          &ip4_hdr->src_address,
                                                          sctp_hdr->dst_port,
                                                          sctp_hdr->src_port,
                                                          TRANSPORT_PROTO_SCTP,
                                                          my_thread_index,
                                                          &result);
            }
          else
            {
              ip6_hdr = vlib_buffer_get_current (b0);
              sctp_hdr = ip6_next_header (ip6_hdr);

              sctp_full_hdr_t *full_hdr = (sctp_full_hdr_t *) sctp_hdr;
              sctp_chunk_hdr = &full_hdr->common_hdr;

              n_advance_bytes0 = sctp_header_bytes ();
              n_data_bytes0 =
                clib_net_to_host_u16 (ip6_hdr->payload_length) -
                n_advance_bytes0;
              n_advance_bytes0 += sizeof (ip6_hdr[0]);

              trans_conn = session_lookup_connection_wt6 (fib_index0,
                                                          &ip6_hdr->dst_address,
                                                          &ip6_hdr->src_address,
                                                          sctp_hdr->dst_port,
                                                          sctp_hdr->src_port,
                                                          TRANSPORT_PROTO_SCTP,
                                                          my_thread_index,
                                                          &result);
            }

          /* Length check */
          if (PREDICT_FALSE (n_advance_bytes0 < 0))
            {
              error0 = SCTP_ERROR_LENGTH;
              goto done;
            }

          sctp_conn = sctp_get_connection_from_transport (trans_conn);
          vnet_sctp_common_hdr_params_net_to_host (sctp_chunk_hdr);

          u8 chunk_type = vnet_sctp_get_chunk_type (sctp_chunk_hdr);
          if (chunk_type >= UNKNOWN)
            {
              clib_warning
                ("Received an unrecognized chunk; sending back OPERATION_ERROR chunk");

              sctp_prepare_operation_error (sctp_conn, SCTP_PRIMARY_PATH_IDX,
                                            b0, UNRECOGNIZED_CHUNK_TYPE);

              error0 = SCTP_ERROR_UNKNOWN_CHUNK;
              next0 = sctp_next_output (is_ip4);
              goto done;
            }

          vnet_buffer (b0)->sctp.hdr_offset =
            (u8 *) sctp_hdr - (u8 *) vlib_buffer_get_current (b0);

          /* Session exists */
          if (PREDICT_TRUE (0 != sctp_conn))
            {
              /* Save connection index */
              vnet_buffer (b0)->sctp.connection_index = trans_conn->c_index;
              vnet_buffer (b0)->sctp.data_offset = n_advance_bytes0;
              vnet_buffer (b0)->sctp.data_len = n_data_bytes0;

              next0 = tm->dispatch_table[sctp_conn->state][chunk_type].next;
              error0 = tm->dispatch_table[sctp_conn->state][chunk_type].error;

              SCTP_DBG_STATE_MACHINE
                ("S_INDEX = %u, C_INDEX = %u, TRANS_CONN = %p, SCTP_CONN = %p, CURRENT_CONNECTION_STATE = %s,"
                 "CHUNK_TYPE_RECEIVED = %s " "NEXT_PHASE = %s",
                 sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
                 connection.s_index,
                 sctp_conn->sub_conn[SCTP_PRIMARY_PATH_IDX].
                 connection.c_index, trans_conn, sctp_conn,
                 sctp_state_to_string (sctp_conn->state),
                 sctp_chunk_to_string (chunk_type), phase_to_string (next0));

              if (chunk_type == DATA)
                SCTP_ADV_DBG ("n_advance_bytes0 = %u, n_data_bytes0 = %u",
                              n_advance_bytes0, n_data_bytes0);

            }
          else
            {
              if (result)
                {
                  next0 = SCTP_INPUT_NEXT_DROP;
                  error0 = SCTP_ERROR_NONE + result;
                }
              else if ((is_ip4 && tm->punt_unknown4) ||
                       (!is_ip4 && tm->punt_unknown6))
                {
                  next0 = SCTP_INPUT_NEXT_PUNT_PHASE;
                  error0 = SCTP_ERROR_PUNT;
                }
              else
                {
                  next0 = SCTP_INPUT_NEXT_DROP;
                  error0 = SCTP_ERROR_NO_LISTENER;
                }
              SCTP_DBG_STATE_MACHINE ("sctp_conn == NULL, NEXT_PHASE = %s",
                                      phase_to_string (next0));
              sctp_conn = 0;
            }

        done:
          b0->error = error0 ? node->errors[error0] : 0;

          if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              sctp_rx_trace_t *t0 =
                vlib_add_trace (vm, node, b0, sizeof (*t0));
              sctp_set_rx_trace_data (t0, sctp_conn, sctp_hdr, b0, is_ip4);
            }
          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 from_frame->n_vectors;
}

static uword
sctp4_input_dispatcher (vlib_main_t * vm, vlib_node_runtime_t * node,
                        vlib_frame_t * from_frame)
{
  return sctp46_input_dispatcher (vm, node, from_frame, 1 /* is_ip4 */ );
}

static uword
sctp6_input_dispatcher (vlib_main_t * vm, vlib_node_runtime_t * node,
                        vlib_frame_t * from_frame)
{
  return sctp46_input_dispatcher (vm, node, from_frame, 0 /* is_ip4 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp4_input_node) =
{
  .function = sctp4_input_dispatcher,
  .name = "sctp4-input",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_INPUT_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_INPUT_NEXT_##s] = n,
    foreach_sctp4_input_next
#undef _
  },
  .format_buffer = format_sctp_header,
  .format_trace = format_sctp_rx_trace,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp4_input_node, sctp4_input_dispatcher);

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (sctp6_input_node) =
{
  .function = sctp6_input_dispatcher,
  .name = "sctp6-input",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_errors = SCTP_N_ERROR,
  .error_strings = sctp_error_strings,
  .n_next_nodes = SCTP_INPUT_N_NEXT,
  .next_nodes =
  {
#define _(s,n) [SCTP_INPUT_NEXT_##s] = n,
    foreach_sctp6_input_next
#undef _
  },
  .format_buffer = format_sctp_header,
  .format_trace = format_sctp_rx_trace,
};
/* *INDENT-ON* */

VLIB_NODE_FUNCTION_MULTIARCH (sctp6_input_node, sctp6_input_dispatcher);

vlib_node_registration_t sctp4_input_node;
vlib_node_registration_t sctp6_input_node;

static void
sctp_dispatch_table_init (sctp_main_t * tm)
{
  int i, j;
  for (i = 0; i < ARRAY_LEN (tm->dispatch_table); i++)
    for (j = 0; j < ARRAY_LEN (tm->dispatch_table[i]); j++)
      {
        tm->dispatch_table[i][j].next = SCTP_INPUT_NEXT_DROP;
        tm->dispatch_table[i][j].error = SCTP_ERROR_DISPATCH;
      }

#define _(t,f,n,e)                                              \
do {                                                            \
    tm->dispatch_table[SCTP_STATE_##t][f].next = (n);           \
    tm->dispatch_table[SCTP_STATE_##t][f].error = (e);          \
} while (0)

  /*
   * SCTP STATE-MACHINE states:
   *
   * _(CLOSED, "CLOSED")                         \
   * _(COOKIE_WAIT, "COOKIE_WAIT")               \
   * _(COOKIE_ECHOED, "COOKIE_ECHOED")           \
   * _(ESTABLISHED, "ESTABLISHED")               \
   * _(SHUTDOWN_PENDING, "SHUTDOWN_PENDING")     \
   * _(SHUTDOWN_SENT, "SHUTDOWN_SENT")           \
   * _(SHUTDOWN_RECEIVED, "SHUTDOWN_RECEIVED")   \
   * _(SHUTDOWN_ACK_SENT, "SHUTDOWN_ACK_SENT")
   */
  //_(CLOSED, DATA, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);     /* UNEXPECTED DATA chunk which requires special handling */
  _(CLOSED, INIT, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);
  _(CLOSED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);        /* UNEXPECTED INIT_ACK chunk */
  _(CLOSED, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);       /* UNEXPECTED SACK chunk */
  _(CLOSED, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);     /* UNEXPECTED HEARTBEAT chunk */
  _(CLOSED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);     /* UNEXPECTED HEARTBEAT_ACK chunk */
  _(CLOSED, ABORT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);
  _(CLOSED, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);       /* UNEXPECTED SHUTDOWN chunk */
  _(CLOSED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);       /* UNEXPECTED SHUTDOWN_ACK chunk */
  _(CLOSED, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);       /* UNEXPECTED OPERATION_ERROR chunk */
  _(CLOSED, COOKIE_ECHO, SCTP_INPUT_NEXT_ESTABLISHED_PHASE, SCTP_ERROR_NONE);
  _(CLOSED, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);      /* UNEXPECTED COOKIE_ACK chunk */
  _(CLOSED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);     /* UNEXPECTED ECNE chunk */
  _(CLOSED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);       /* UNEXPECTED CWR chunk */
  _(CLOSED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);   /* UNEXPECTED SHUTDOWN_COMPLETE chunk */
  _(CLOSED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);

  _(COOKIE_WAIT, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_NONE);  /* UNEXPECTED DATA chunk which requires special handling */
  _(COOKIE_WAIT, INIT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);     /* UNEXPECTED INIT chunk which requires special handling */
  _(COOKIE_WAIT, INIT_ACK, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);
  _(COOKIE_WAIT, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);  /* UNEXPECTED SACK chunk */
  _(COOKIE_WAIT, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);        /* UNEXPECTED HEARTBEAT chunk */
  _(COOKIE_WAIT, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);        /* UNEXPECTED HEARTBEAT_ACK chunk */
  _(COOKIE_WAIT, ABORT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);
  _(COOKIE_WAIT, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);  /* UNEXPECTED SHUTDOWN chunk */
  _(COOKIE_WAIT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);  /* UNEXPECTED SHUTDOWN_ACK chunk */
  _(COOKIE_WAIT, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);  /* UNEXPECTED OPERATION_ERROR chunk */
  _(COOKIE_WAIT, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);  /* UNEXPECTED COOKIE_ECHO chunk */
  _(COOKIE_WAIT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP); /* UNEXPECTED COOKIE_ACK chunk */
  _(COOKIE_WAIT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);        /* UNEXPECTED ECNE chunk */
  _(COOKIE_WAIT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);  /* UNEXPECTED CWR chunk */
  _(COOKIE_WAIT, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);      /* UNEXPECTED SHUTDOWN_COMPLETE chunk */
  _(COOKIE_WAIT, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);

  _(COOKIE_ECHOED, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_NONE);
  _(COOKIE_ECHOED, INIT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);   /* UNEXPECTED INIT chunk which requires special handling */
  _(COOKIE_ECHOED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP); /* UNEXPECTED INIT_ACK chunk */
  _(COOKIE_ECHOED, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);        /* UNEXPECTED SACK chunk */
  _(COOKIE_ECHOED, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);      /* UNEXPECTED HEARTBEAT chunk */
  _(COOKIE_ECHOED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);      /* UNEXPECTED HEARTBEAT_ACK chunk */
  _(COOKIE_ECHOED, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);      /* UNEXPECTED ABORT chunk */
  _(COOKIE_ECHOED, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);        /* UNEXPECTED SHUTDOWN chunk */
  _(COOKIE_ECHOED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);        /* UNEXPECTED SHUTDOWN_ACK chunk */
  _(COOKIE_ECHOED, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);        /* UNEXPECTED OPERATION_ERROR chunk */
  _(COOKIE_ECHOED, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);        /* UNEXPECTED COOKIE_ECHO chunk */
  _(COOKIE_ECHOED, COOKIE_ACK, SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
    SCTP_ERROR_NONE);
  _(COOKIE_ECHOED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);      /* UNEXPECTED ECNE chunk */
  _(COOKIE_ECHOED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);        /* UNEXPECTED CWR chunk */
  _(COOKIE_ECHOED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);    /* UNEXPECTED SHUTDOWN_COMPLETE chunk */
  _(COOKIE_ECHOED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);

  _(ESTABLISHED, DATA, SCTP_INPUT_NEXT_ESTABLISHED_PHASE, SCTP_ERROR_NONE);
  _(ESTABLISHED, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);  /* UNEXPECTED INIT chunk */
  _(ESTABLISHED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);   /* UNEXPECTED INIT_ACK chunk */
  _(ESTABLISHED, SACK, SCTP_INPUT_NEXT_ESTABLISHED_PHASE, SCTP_ERROR_NONE);
  _(ESTABLISHED, HEARTBEAT, SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
    SCTP_ERROR_NONE);
  _(ESTABLISHED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_ESTABLISHED_PHASE,
    SCTP_ERROR_NONE);
  _(ESTABLISHED, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);        /* UNEXPECTED ABORT chunk */
  _(ESTABLISHED, SHUTDOWN, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
  _(ESTABLISHED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);  /* UNEXPECTED SHUTDOWN_ACK chunk */
  _(ESTABLISHED, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);  /* UNEXPECTED OPERATION_ERROR chunk */
  _(ESTABLISHED, COOKIE_ECHO, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_COOKIE_ECHO_VIOLATION);  /* UNEXPECTED COOKIE_ECHO chunk */
  _(ESTABLISHED, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP); /* UNEXPECTED COOKIE_ACK chunk */
  _(ESTABLISHED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);        /* UNEXPECTED ECNE chunk */
  _(ESTABLISHED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);  /* UNEXPECTED CWR chunk */
  _(ESTABLISHED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);      /* UNEXPECTED SHUTDOWN_COMPLETE chunk */
  _(ESTABLISHED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);

  _(SHUTDOWN_PENDING, DATA, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
  _(SHUTDOWN_PENDING, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);     /* UNEXPECTED INIT chunk */
  _(SHUTDOWN_PENDING, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);      /* UNEXPECTED INIT_ACK chunk */
  _(SHUTDOWN_PENDING, SACK, SCTP_INPUT_NEXT_LISTEN_PHASE, SCTP_ERROR_NONE);
  _(SHUTDOWN_PENDING, HEARTBEAT, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_PENDING, HEARTBEAT_ACK, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_PENDING, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);   /* UNEXPECTED ABORT chunk */
  _(SHUTDOWN_PENDING, SHUTDOWN, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_PENDING, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);     /* UNEXPECTED SHUTDOWN_ACK chunk */
  _(SHUTDOWN_PENDING, OPERATION_ERROR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_OPERATION_ERROR_VIOLATION);     /* UNEXPECTED OPERATION_ERROR chunk */
  _(SHUTDOWN_PENDING, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_PENDING, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);    /* UNEXPECTED COOKIE_ACK chunk */
  _(SHUTDOWN_PENDING, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);   /* UNEXPECTED ECNE chunk */
  _(SHUTDOWN_PENDING, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);     /* UNEXPECTED CWR chunk */
  _(SHUTDOWN_PENDING, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION); /* UNEXPECTED SHUTDOWN_COMPLETE chunk */
  _(SHUTDOWN_PENDING, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);

  _(SHUTDOWN_SENT, DATA, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
  _(SHUTDOWN_SENT, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);        /* UNEXPECTED INIT chunk */
  _(SHUTDOWN_SENT, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP); /* UNEXPECTED INIT_ACK chunk */
  _(SHUTDOWN_SENT, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);        /* UNEXPECTED SACK chunk */
  _(SHUTDOWN_SENT, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);      /* UNEXPECTED HEARTBEAT chunk */
  _(SHUTDOWN_SENT, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);      /* UNEXPECTED HEARTBEAT_ACK chunk */
  _(SHUTDOWN_SENT, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);      /* UNEXPECTED ABORT chunk */
  _(SHUTDOWN_SENT, SHUTDOWN, SCTP_INPUT_NEXT_SHUTDOWN_PHASE, SCTP_ERROR_NONE);
  _(SHUTDOWN_SENT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_SENT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);       /* UNEXPECTED COOKIE_ACK chunk */
  _(SHUTDOWN_SENT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);      /* UNEXPECTED ECNE chunk */
  _(SHUTDOWN_SENT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);        /* UNEXPECTED CWR chunk */
  _(SHUTDOWN_SENT, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);    /* UNEXPECTED SHUTDOWN_COMPLETE chunk */
  _(SHUTDOWN_SENT, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);

  _(SHUTDOWN_RECEIVED, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_DATA_CHUNK_VIOLATION);    /* UNEXPECTED DATA chunk */
  _(SHUTDOWN_RECEIVED, INIT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_INIT_CHUNK_VIOLATION);    /* UNEXPECTED INIT chunk */
  _(SHUTDOWN_RECEIVED, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);     /* UNEXPECTED INIT_ACK chunk */
  _(SHUTDOWN_RECEIVED, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);    /* UNEXPECTED INIT chunk */
  _(SHUTDOWN_RECEIVED, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);  /* UNEXPECTED HEARTBEAT chunk */
  _(SHUTDOWN_RECEIVED, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);  /* UNEXPECTED HEARTBEAT_ACK chunk */
  _(SHUTDOWN_RECEIVED, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);  /* UNEXPECTED ABORT chunk */
  _(SHUTDOWN_RECEIVED, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);    /* UNEXPECTED SHUTDOWN chunk */
  _(SHUTDOWN_RECEIVED, SHUTDOWN_ACK, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_RECEIVED, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_RECEIVED, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);   /* UNEXPECTED COOKIE_ACK chunk */
  _(SHUTDOWN_RECEIVED, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);  /* UNEXPECTED ECNE chunk */
  _(SHUTDOWN_RECEIVED, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);    /* UNEXPECTED CWR chunk */
  _(SHUTDOWN_RECEIVED, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_COMPLETE_VIOLATION);        /* UNEXPECTED SHUTDOWN_COMPLETE chunk */
  _(SHUTDOWN_RECEIVED, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);

  _(SHUTDOWN_ACK_SENT, DATA, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_DATA_CHUNK_VIOLATION);    /* UNEXPECTED DATA chunk */
  _(SHUTDOWN_ACK_SENT, INIT, SCTP_INPUT_NEXT_RCV_PHASE, SCTP_ERROR_NONE);       /* UNEXPECTED INIT chunk */
  _(SHUTDOWN_ACK_SENT, INIT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);     /* UNEXPECTED INIT_ACK chunk */
  _(SHUTDOWN_ACK_SENT, SACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SACK_CHUNK_VIOLATION);    /* UNEXPECTED INIT chunk */
  _(SHUTDOWN_ACK_SENT, HEARTBEAT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_CHUNK_VIOLATION);  /* UNEXPECTED HEARTBEAT chunk */
  _(SHUTDOWN_ACK_SENT, HEARTBEAT_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_HEARTBEAT_ACK_CHUNK_VIOLATION);  /* UNEXPECTED HEARTBEAT_ACK chunk */
  _(SHUTDOWN_ACK_SENT, ABORT, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ABORT_CHUNK_VIOLATION);  /* UNEXPECTED ABORT chunk */
  _(SHUTDOWN_ACK_SENT, SHUTDOWN, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_CHUNK_VIOLATION);    /* UNEXPECTED SHUTDOWN chunk */
  _(SHUTDOWN_ACK_SENT, SHUTDOWN_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_SHUTDOWN_ACK_CHUNK_VIOLATION);    /* UNEXPECTED SHUTDOWN_ACK chunk */
  _(SHUTDOWN_ACK_SENT, COOKIE_ECHO, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_ACK_SENT, COOKIE_ACK, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ACK_DUP);   /* UNEXPECTED COOKIE_ACK chunk */
  _(SHUTDOWN_ACK_SENT, ECNE, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_ECNE_VIOLATION);  /* UNEXPECTED ECNE chunk */
  _(SHUTDOWN_ACK_SENT, CWR, SCTP_INPUT_NEXT_DROP, SCTP_ERROR_CWR_VIOLATION);    /* UNEXPECTED CWR chunk */
  _(SHUTDOWN_ACK_SENT, SHUTDOWN_COMPLETE, SCTP_INPUT_NEXT_SHUTDOWN_PHASE,
    SCTP_ERROR_NONE);
  _(SHUTDOWN_ACK_SENT, OPERATION_ERROR, SCTP_INPUT_NEXT_LISTEN_PHASE,
    SCTP_ERROR_NONE);

  /* TODO: Handle COOKIE ECHO when a TCB Exists */

#undef _
}

clib_error_t *
sctp_input_init (vlib_main_t * vm)
{
  clib_error_t *error = 0;
  sctp_main_t *tm = vnet_get_sctp_main ();

  if ((error = vlib_call_init_function (vm, sctp_init)))
    return error;

  /* Initialize dispatch table. */
  sctp_dispatch_table_init (tm);

  return error;
}

VLIB_INIT_FUNCTION (sctp_input_init);

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