/*
 * Copyright (c) 2021-2022 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <vnet/dpo/dpo.h>

#include "data_fwd.h"
#include "mgmt.h"
#include "parser.h"
#include "infra.h"
#include "strategy.h"
#include "strategy_dpo_manager.h"
#include "state.h"
#include "error.h"

/* Stats string values */
static char *hicn_data_fwd_error_strings[] = {
#define _(sym, string) string,
  foreach_hicnfwd_error
#undef _
};

/* Declarations */
always_inline void
drop_packet (vlib_main_t *vm, u32 bi0, u32 *n_left_to_next, u32 *next0,
	     u32 **to_next, u32 *next_index, vlib_node_runtime_t *node)
{
  *next0 = HICN_DATA_FWD_NEXT_ERROR_DROP;

  (*to_next)[0] = bi0;
  *to_next += 1;
  *n_left_to_next -= 1;

  vlib_validate_buffer_enqueue_x1 (vm, node, *next_index, *to_next,
				   *n_left_to_next, bi0, *next0);
}

always_inline int
hicn_satisfy_faces (vlib_main_t *vm, u32 bi0, hicn_pcs_entry_t *pitp,
		    u32 *n_left_to_next, u32 **to_next, u32 *next_index,
		    vlib_node_runtime_t *node, u8 isv6,
		    vl_api_hicn_api_node_stats_get_reply_t *stats)
{
  int found = 0;
  int ret = HICN_ERROR_NONE;
  u32 inline_clones[HICN_FACE_DB_INLINE_FACES];
  u32 *clones = inline_clones, *header = NULL;
  u32 n_left_from = 0;
  u32 next0 = HICN_DATA_FWD_NEXT_ERROR_DROP,
      next1 = HICN_DATA_FWD_NEXT_ERROR_DROP;
  word buffer_advance = CLIB_CACHE_LINE_BYTES * 2;

  /*
   * We have a hard limit on the number of vlib_buffer that we can
   * chain (no more than 256)
   */
  /*
   * The first group of vlib_buffer can be directly cloned from b0. We
   * need to be careful to clone it only 254 times as the buffer
   * already has n_add_reds=1.
   */
  if (hicn_pcs_entry_pit_get_n_faces (pitp) > HICN_FACE_DB_INLINE_FACES)
    {
      vec_alloc (clones, hicn_pcs_entry_pit_get_n_faces (pitp));
      header = clones;
    }

  /* Clone bi0 */
  vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);

  hicn_buffer_t *hicnb = hicn_get_buffer (b0);

  /*
   * Mark the buffer as smaller than TWO_CL. It will be stored as is in the CS,
   * without excluding the hicn_header. Cloning is not possible, it will be
   * copied.
   */
  if (b0->current_length <= (buffer_advance + (CLIB_CACHE_LINE_BYTES * 2)))
    {
      /* In this case the packet is copied. We don't need to add a reference as
       * no buffer are chained to it.
       */
      hicnb->flags |= HICN_BUFFER_FLAGS_PKT_LESS_TWO_CL;
    }
  else
    {
      /* Add one reference to maintain the buffer in the CS.
       * b0->ref_count == 0 has two meaning: it has 1 buffer or no buffer
       * chained to it. vlib_buffer_clone2 add a number of reference equal to
       * pitp->u.pit.faces.n_faces - 1 as vlib_buffer_clone does. So after all
       * the packet are forwarded the buffer stored in the CS will have
       * ref_count == 0;
       */
      b0->ref_count++;
    }

  found = n_left_from =
    vlib_buffer_clone2 (vm, bi0, clones, pitp->u.pit.n_faces, buffer_advance);

  ASSERT (n_left_from == hicn_pcs_entry_pit_get_n_faces (pitp));

  /* Index to iterate over the faces */
  int i = 0;

  while (n_left_from > 0)
    {
      // Dual loop, X2
      while (n_left_from >= 4 && *n_left_to_next >= 2)
	{
	  vlib_buffer_t *h0, *h1;
	  u32 hi0, hi1;
	  hicn_face_id_t face0, face1;

	  /* Prefetch for next iteration. */
	  {
	    vlib_buffer_t *h2, *h3;
	    h2 = vlib_get_buffer (vm, clones[2]);
	    h3 = vlib_get_buffer (vm, clones[3]);
	    CLIB_PREFETCH (h2, 2 * CLIB_CACHE_LINE_BYTES, STORE);
	    CLIB_PREFETCH (h3, 2 * CLIB_CACHE_LINE_BYTES, STORE);
	  }

	  face0 = hicn_pcs_entry_pit_get_dpo_face (pitp, i);
	  face1 = hicn_pcs_entry_pit_get_dpo_face (pitp, i + 1);

	  // Increment index
	  i += 2;

	  h0 = vlib_get_buffer (vm, clones[0]);
	  h1 = vlib_get_buffer (vm, clones[1]);

	  (*to_next)[0] = hi0 = clones[0];
	  (*to_next)[1] = hi1 = clones[1];
	  *to_next += 2;
	  *n_left_to_next -= 2;
	  n_left_from -= 2;
	  clones += 2;

	  next0 = isv6 ? HICN_DATA_FWD_NEXT_IFACE6_OUT :
			       HICN_DATA_FWD_NEXT_IFACE4_OUT;
	  next1 = isv6 ? HICN_DATA_FWD_NEXT_IFACE6_OUT :
			       HICN_DATA_FWD_NEXT_IFACE4_OUT;

	  vnet_buffer (h0)->ip.adj_index[VLIB_TX] = face0;
	  vnet_buffer (h1)->ip.adj_index[VLIB_TX] = face1;

	  stats->pkts_data_count += 2;

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (h0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      hicn_data_fwd_trace_t *t =
		vlib_add_trace (vm, node, h0, sizeof (*t));
	      t->face = face0;
	      t->pkt_type = HICN_PACKET_TYPE_DATA;
	      t->sw_if_index = vnet_buffer (h0)->sw_if_index[VLIB_RX];
	      t->next_index = next0;
	      clib_memcpy (t->packet_data, vlib_buffer_get_current (h0),
			   sizeof (t->packet_data));
	    }
	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (h1->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      hicn_data_fwd_trace_t *t =
		vlib_add_trace (vm, node, h1, sizeof (*t));
	      t->face = face1;
	      t->pkt_type = HICN_PACKET_TYPE_DATA;
	      t->sw_if_index = vnet_buffer (h1)->sw_if_index[VLIB_RX];
	      t->next_index = next1;
	      clib_memcpy (t->packet_data, vlib_buffer_get_current (h1),
			   sizeof (t->packet_data));
	    }
	  vlib_validate_buffer_enqueue_x2 (vm, node, *next_index, (*to_next),
					   *n_left_to_next, hi0, hi1, next0,
					   next1);
	}

      while (n_left_from > 0 && *n_left_to_next > 0)
	{
	  vlib_buffer_t *h0;
	  u32 hi0;
	  hicn_face_id_t face0;

	  face0 = hicn_pcs_entry_pit_get_dpo_face (pitp, i);
	  i += 1;

	  h0 = vlib_get_buffer (vm, clones[0]);

	  (*to_next)[0] = hi0 = clones[0];
	  *to_next += 1;
	  *n_left_to_next -= 1;
	  n_left_from -= 1;
	  clones += 1;

	  next0 = isv6 ? HICN_DATA_FWD_NEXT_IFACE6_OUT :
			       HICN_DATA_FWD_NEXT_IFACE4_OUT;
	  vnet_buffer (h0)->ip.adj_index[VLIB_TX] = face0;

	  stats->pkts_data_count++;

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (h0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      hicn_data_fwd_trace_t *t =
		vlib_add_trace (vm, node, h0, sizeof (*t));
	      t->face = face0;
	      t->pkt_type = HICN_PACKET_TYPE_DATA;
	      t->sw_if_index = vnet_buffer (h0)->sw_if_index[VLIB_RX];
	      t->next_index = next0;
	      clib_memcpy (t->packet_data, vlib_buffer_get_current (h0),
			   sizeof (t->packet_data));
	    }
	  /*
	   * Verify speculative enqueue, maybe switch current
	   * next frame
	   */
	  /*
	   * Fix in case of a wrong speculation. Needed to
	   * clone the data in the right frame
	   */
	  vlib_validate_buffer_enqueue_x1 (vm, node, *next_index, *to_next,
					   *n_left_to_next, hi0, next0);
	}

      /* Ensure that there is space for the next clone (if any) */
      if (PREDICT_FALSE (*n_left_to_next == 0))
	{
	  vlib_put_next_frame (vm, node, *next_index, *n_left_to_next);

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

  vec_free (header);

  if (PREDICT_FALSE (!found))
    {
      ASSERT (0);
      drop_packet (vm, bi0, n_left_to_next, &next0, to_next, next_index, node);
      ret = HICN_ERROR_FACE_NOT_FOUND;
    }
  return ret;
}

always_inline void
clone_data_to_cs (hicn_pit_cs_t *pitcs, hicn_pcs_entry_t *pcs_entry,
		  u32 buffer_index, f64 tnow, hicn_lifetime_t dmsg_lifetime)
{
  /*
   * At this point we think we're safe to proceed. Store the CS buf in
   * the PIT/CS hashtable entry
   */

  // Start turning the PIT into a CS. Note that we may be stepping on the PIT
  // part of the union as we update the CS part, so don't expect the PIT part
  // to be valid after this point.
  hicn_pit_to_cs (pitcs, pcs_entry, buffer_index);
  hicn_pcs_entry_set_create_time (pcs_entry, tnow);

  if (dmsg_lifetime < HICN_PARAM_CS_LIFETIME_MIN ||
      dmsg_lifetime > HICN_PARAM_CS_LIFETIME_MAX)
    {
      dmsg_lifetime = HICN_PARAM_CS_LIFETIME_DFLT;
    }
  hicn_pcs_entry_set_expire_time (pcs_entry,
				  hicn_pcs_get_exp_time (tnow, dmsg_lifetime));
}

/* packet trace format function */
always_inline u8 *
hicn_data_fwd_format_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 *);
  hicn_data_fwd_trace_t *t = va_arg (*args, hicn_data_fwd_trace_t *);
  u32 indent = format_get_indent (s);

  s = format (s, "DATAFWD: pkt: %d, sw_if_index %d, next index %d, face %d\n",
	      (int) t->pkt_type, t->sw_if_index, t->next_index, t->face);

  s = format (s, "%U%U", format_white_space, indent, format_ip6_header,
	      t->packet_data, sizeof (t->packet_data));
  return (s);
}

vlib_node_registration_t hicn_data_fwd_node;

/*
 * ICN forwarder node for interests: handling of Data delivered based on ACL.
 * - 1 packet at a time - ipv4/tcp ipv6/tcp
 */
static uword
hicn_data_node_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
		   vlib_frame_t *frame)
{

  u32 n_left_from, *from, *to_next;
  hicn_data_fwd_next_t next_index;
  hicn_data_fwd_runtime_t *rt;
  vl_api_hicn_api_node_stats_get_reply_t stats = { 0 };
  f64 tnow;
  u32 data_received = 1;
  vlib_buffer_t *b0;
  u8 isv6;
  u32 bi0;
  u32 next0 = HICN_DATA_FWD_NEXT_ERROR_DROP;
  hicn_buffer_t *hicnb0;
  const hicn_strategy_vft_t *strategy_vft0 = NULL;
  const hicn_dpo_vft_t *dpo_vft0;
  u8 dpo_ctx_id0 = ~0;
  u32 pcs_entry_id;
  hicn_pcs_entry_t *pcs_entry = NULL;
  hicn_lifetime_t dmsg_lifetime;
  int ret = HICN_ERROR_NONE;

  rt = vlib_node_get_runtime_data (vm, node->node_index);

  if (PREDICT_FALSE (rt->pitcs == NULL))
    {
      rt->pitcs = &hicn_main.pitcs;
    }

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

  /* Capture time in vpp terms */
  tnow = vlib_time_now (vm);

  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)
	{
	  /* Prefetch for next iteration. */
	  if (n_left_from > 1)
	    {
	      vlib_buffer_t *b1;
	      b1 = vlib_get_buffer (vm, from[1]);
	      CLIB_PREFETCH (b1, 2 * CLIB_CACHE_LINE_BYTES, STORE);
	    }

	  // Dequeue a packet buffer. Do not copy the index in the next buffer,
	  // we'll do it later. The packet might be cloned, so the buffer to
	  // move to next must be the cloned one
	  bi0 = from[0];
	  from += 1;
	  n_left_from -= 1;

	  b0 = vlib_get_buffer (vm, bi0);

	  // Get hicn buffer and state
	  hicnb0 = hicn_get_buffer (b0);

	  hicn_get_internal_state (hicnb0, &pcs_entry_id, &strategy_vft0,
				   &dpo_vft0, &dpo_ctx_id0);

	  // Get PCS entry
	  pcs_entry =
	    hicn_pcs_entry_get_entry_from_index_safe (rt->pitcs, pcs_entry_id);

	  if (PREDICT_FALSE (pcs_entry == NULL))
	    {
	      drop_packet (vm, bi0, &n_left_to_next, &next0, &to_next,
			   &next_index, node);

	      goto end_processing;
	    }

	  isv6 = hicn_buffer_is_v6 (b0);

	  // If PCS entry is CS, drop the packet
	  if (PREDICT_FALSE (hicn_pcs_entry_is_cs (pcs_entry)))
	    {
	      drop_packet (vm, bi0, &n_left_to_next, &next0, &to_next,
			   &next_index, node);

	      goto end_processing;
	    }

	  // We are sure the entry is a PIT entry. Check whether it is expired.
	  if (tnow > hicn_pcs_entry_get_expire_time (pcs_entry))
	    {
	      // Entry expired. Release lock
	      hicn_pcs_entry_remove_lock (rt->pitcs, pcs_entry);

	      // Drop packet
	      drop_packet (vm, bi0, &n_left_to_next, &next0, &to_next,
			   &next_index, node);

	      // Update stats
	      stats.pit_expired_count++;

	      // Trace
	      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
				 (b0->flags & VLIB_BUFFER_IS_TRACED)))
		{
		  hicn_data_fwd_trace_t *t =
		    vlib_add_trace (vm, node, b0, sizeof (*t));
		  t->pkt_type = HICN_PACKET_TYPE_DATA;
		  t->sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
		  t->next_index = next0;
		  clib_memcpy (t->packet_data, vlib_buffer_get_current (b0),
			       sizeof (t->packet_data));
		}
	    }
	  else
	    {
	      // Update stats
	      data_received++;

	      /*
	       * We do not check if the data is coming from
	       * the outgoing interest face.
	       */

	      // Prepare the buffer for the cloning
	      ret =
		hicn_satisfy_faces (vm, bi0, pcs_entry, &n_left_to_next,
				    &to_next, &next_index, node, isv6, &stats);

	      if (PREDICT_FALSE (ret != HICN_ERROR_NONE))
		{
		  hicn_pcs_entry_remove_lock (rt->pitcs, pcs_entry);
		  continue;
		}

	      // Call the strategy callback since the  interest has been
	      // satisfied
	      strategy_vft0->hicn_receive_data (
		dpo_ctx_id0, vnet_buffer (b0)->ip.adj_index[VLIB_RX]);

	      dmsg_lifetime = hicn_buffer_get_lifetime (b0);

	      if (dmsg_lifetime)
		{
		  // Clone data packet in the content store and convert the PIT
		  // entry into a CS entry
		  clone_data_to_cs (rt->pitcs, pcs_entry, bi0, tnow,
				    dmsg_lifetime);
		}
	      else
		{
		  /*
		   * If the packet is copied and not cloned, we need to free
		   * the vlib_buffer
		   */
		  if (hicnb0->flags & HICN_BUFFER_FLAGS_PKT_LESS_TWO_CL)
		    {
		      vlib_buffer_free_one (vm, bi0);
		    }
		  else
		    {
		      /*
		       * Remove one reference as the buffer is no
		       * longer in any frame. The vlib_buffer will be freed
		       * when all its cloned vlib_buffer will be freed.
		       */
		      b0->ref_count--;
		    }
		  // Delete the PIT entry
		  hicn_pcs_entry_remove_lock (rt->pitcs, pcs_entry);
		}
	    }
	end_processing:

	  /* Incr packet counter */
	  stats.pkts_processed += 1;
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }
  u32 pit_int_count = hicn_pcs_get_pit_count (rt->pitcs);
  u32 pit_cs_count = hicn_pcs_get_cs_count (rt->pitcs);

  vlib_node_increment_counter (vm, hicn_data_fwd_node.index,
			       HICNFWD_ERROR_DATAS, stats.pkts_data_count);

  update_node_counter (vm, hicn_data_fwd_node.index, HICNFWD_ERROR_INT_COUNT,
		       pit_int_count);
  update_node_counter (vm, hicn_data_fwd_node.index, HICNFWD_ERROR_CS_COUNT,
		       pit_cs_count);
  update_node_counter (vm, hicn_data_fwd_node.index,
		       HICNFWD_ERROR_INTEREST_AGG_ENTRY,
		       stats.pkts_data_count / data_received);

  return (frame->n_vectors);
}

/*
 * Node registration for the data forwarder node
 */
VLIB_REGISTER_NODE(hicn_data_fwd_node) =
{
  .function = hicn_data_node_fn,
  .name = "hicn-data-fwd",
  .vector_size = sizeof(u32),
  .format_trace = hicn_data_fwd_format_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(hicn_data_fwd_error_strings),
  .error_strings = hicn_data_fwd_error_strings,
  .n_next_nodes = HICN_DATA_FWD_N_NEXT,
  /* edit / add dispositions here */
  .next_nodes = {
    [HICN_DATA_FWD_NEXT_V4_LOOKUP] = "ip4-lookup",
    [HICN_DATA_FWD_NEXT_V6_LOOKUP] = "ip6-lookup",
    [HICN_DATA_FWD_NEXT_IFACE4_OUT] = "hicn4-iface-output",
    [HICN_DATA_FWD_NEXT_IFACE6_OUT] = "hicn6-iface-output",
    [HICN_DATA_FWD_NEXT_ERROR_DROP] = "error-drop",
  },
};

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