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

#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vnet/pg/pg.h>
#include <vnet/ip/ip.h>
#include <vnet/ethernet/ethernet.h>

#include "hicn.h"
#include "pg.h"
#include "parser.h"
#include "infra.h"

/* Registration struct for a graph node */
vlib_node_registration_t hicn_pg_interest_node;
vlib_node_registration_t hicn_pg_data_node;

/* Stats, which end up called "error" even though they aren't... */
#define foreach_hicnpg_error                                                  \
  _ (PROCESSED, "hICN PG packets processed")                                  \
  _ (DROPPED, "hICN PG packets dropped")                                      \
  _ (INTEREST_MSGS_GENERATED, "hICN PG Interests generated")                  \
  _ (CONTENT_MSGS_RECEIVED, "hICN PG Content msgs received")

typedef enum
{
#define _(sym, str) HICNPG_ERROR_##sym,
  foreach_hicnpg_error
#undef _
    HICNPG_N_ERROR,
} hicnpg_error_t;

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

/*
 * Next graph nodes, which reference the list in the actual registration
 * block below
 */
typedef enum
{
  HICNPG_INTEREST_NEXT_V4_LOOKUP,
  HICNPG_INTEREST_NEXT_V6_LOOKUP,
  HICNPG_INTEREST_NEXT_DROP,
  HICNPG_N_NEXT,
} hicnpg_interest_next_t;

/* Trace context struct */
typedef struct
{
  u32 next_index;
  u32 sw_if_index;
  u8 pkt_type;
  u16 msg_type;
} hicnpg_trace_t;

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

  s = format (s, "HICNPG: pkt: %d, msg %d, sw_if_index %d, next index %d",
	      (int) t->pkt_type, (int) t->msg_type, t->sw_if_index,
	      t->next_index);
  return (s);
}

always_inline void hicn_rewrite_interestv4 (vlib_main_t *vm, vlib_buffer_t *b0,
					    u32 seq_number, u16 lifetime,
					    u32 next_flow, u32 iface);

always_inline void hicn_rewrite_interestv6 (vlib_main_t *vm, vlib_buffer_t *b0,
					    u32 seq_number, u16 lifetime,
					    u32 next_flow, u32 iface);

always_inline void convert_interest_to_data_v4 (vlib_main_t *vm,
						vlib_buffer_t *b0,
						vlib_buffer_t *rb, u32 bi0);

always_inline void convert_interest_to_data_v6 (vlib_main_t *vm,
						vlib_buffer_t *b0,
						vlib_buffer_t *rb, u32 bi0);

always_inline void calculate_tcp_checksum_v4 (vlib_main_t *vm,
					      vlib_buffer_t *b0);

always_inline void calculate_tcp_checksum_v6 (vlib_main_t *vm,
					      vlib_buffer_t *b0);
/*
 * Node function for the icn packet-generator client. The goal here is to
 * manipulate/tweak a stream of packets that have been injected by the vpp
 * packet generator to generate icn request traffic.
 */
static uword
hicnpg_client_interest_node_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
				vlib_frame_t *frame)
{
  u32 n_left_from, *from, *to_next;
  hicnpg_interest_next_t next_index;
  u32 pkts_processed = 0, pkts_dropped = 0;
  u32 interest_msgs_generated = 0;
  u32 bi0, bi1;
  vlib_buffer_t *b0, *b1;
  u8 pkt_type0 = 0, pkt_type1 = 0;
  u16 msg_type0 = 0, msg_type1 = 0;
  hicnpg_main_t *hpgm = &hicnpg_main;
  int iface = 0;

  from = vlib_frame_vector_args (frame);
  n_left_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 >= 4 && n_left_to_next >= 2)
	{
	  u32 next0 = HICNPG_INTEREST_NEXT_DROP;
	  u32 next1 = HICNPG_INTEREST_NEXT_DROP;
	  u32 sw_if_index0 = ~0, sw_if_index1 = ~0;
	  u8 isv6_0;
	  u8 isv6_1;

	  /* Prefetch next iteration. */
	  {
	    vlib_buffer_t *p2, *p3;

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

	    vlib_prefetch_buffer_header (p2, LOAD);
	    vlib_prefetch_buffer_header (p3, LOAD);

	    CLIB_PREFETCH (p2->data, (2 * CLIB_CACHE_LINE_BYTES), STORE);
	    CLIB_PREFETCH (p3->data, (2 * CLIB_CACHE_LINE_BYTES), STORE);
	  }

	  /*
	   * speculatively enqueue b0 and b1 to the current
	   * next frame
	   */
	  to_next[0] = bi0 = from[0];
	  to_next[1] = bi1 = from[1];
	  from += 2;
	  to_next += 2;
	  n_left_from -= 2;
	  n_left_to_next -= 2;

	  b0 = vlib_get_buffer (vm, bi0);
	  b1 = vlib_get_buffer (vm, bi1);

	  hicn_buffer_set_flags (b0, HICN_BUFFER_FLAGS_FROM_PG);
	  hicn_buffer_set_flags (b1, HICN_BUFFER_FLAGS_FROM_PG);

	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
	  sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = hpgm->sw_if;
	  vnet_buffer (b1)->sw_if_index[VLIB_RX] = hpgm->sw_if;

	  /* Check icn packets, locate names */
	  if (hicn_interest_parse_pkt (b0) == HICN_ERROR_NONE)
	    {
	      /* this node grabs only interests */
	      isv6_0 = hicn_buffer_is_v6 (b0);

	      /* Increment the appropriate message counter */
	      interest_msgs_generated++;

	      iface = (hpgm->index_ifaces % hpgm->n_ifaces);
	      /* Rewrite and send */
	      isv6_0 ?
		      hicn_rewrite_interestv6 (
		  vm, b0, (hpgm->index / hpgm->n_flows) % hpgm->max_seq_number,
		  hpgm->interest_lifetime, hpgm->index % hpgm->n_flows,
		  iface) :
		      hicn_rewrite_interestv4 (
		  vm, b0, (hpgm->index / hpgm->n_flows) % hpgm->max_seq_number,
		  hpgm->interest_lifetime, hpgm->index % hpgm->n_flows, iface);

	      hpgm->index_ifaces++;
	      if (iface == (hpgm->n_ifaces - 1))
		hpgm->index++;

	      next0 = isv6_0 ? HICNPG_INTEREST_NEXT_V6_LOOKUP :
				     HICNPG_INTEREST_NEXT_V4_LOOKUP;
	    }
	  if (hicn_interest_parse_pkt (b1) == HICN_ERROR_NONE)
	    {
	      /* this node grabs only interests */
	      isv6_1 = hicn_buffer_is_v6 (b1);

	      /* Increment the appropriate message counter */
	      interest_msgs_generated++;

	      iface = (hpgm->index_ifaces % hpgm->n_ifaces);
	      /* Rewrite and send */
	      isv6_1 ?
		      hicn_rewrite_interestv6 (
		  vm, b1, (hpgm->index / hpgm->n_flows) % hpgm->max_seq_number,
		  hpgm->interest_lifetime, hpgm->index % hpgm->n_flows,
		  iface) :
		      hicn_rewrite_interestv4 (
		  vm, b1, (hpgm->index / hpgm->n_flows) % hpgm->max_seq_number,
		  hpgm->interest_lifetime, hpgm->index % hpgm->n_flows, iface);

	      hpgm->index_ifaces++;
	      if (iface == (hpgm->n_ifaces - 1))
		hpgm->index++;

	      next1 = isv6_1 ? HICNPG_INTEREST_NEXT_V6_LOOKUP :
				     HICNPG_INTEREST_NEXT_V4_LOOKUP;
	    }
	  /* Send pkt to next node */
	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
	  vnet_buffer (b1)->sw_if_index[VLIB_TX] = ~0;

	  pkts_processed += 2;

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
	    {
	      if (b0->flags & VLIB_BUFFER_IS_TRACED)
		{
		  hicnpg_trace_t *t =
		    vlib_add_trace (vm, node, b0, sizeof (*t));
		  t->pkt_type = pkt_type0;
		  t->msg_type = msg_type0;
		  t->sw_if_index = sw_if_index0;
		  t->next_index = next0;
		}
	      if (b1->flags & VLIB_BUFFER_IS_TRACED)
		{
		  hicnpg_trace_t *t =
		    vlib_add_trace (vm, node, b1, sizeof (*t));
		  t->pkt_type = pkt_type1;
		  t->msg_type = msg_type1;
		  t->sw_if_index = sw_if_index1;
		  t->next_index = next1;
		}
	    }
	  if (next0 == HICNPG_INTEREST_NEXT_DROP)
	    {
	      pkts_dropped++;
	    }
	  if (next1 == HICNPG_INTEREST_NEXT_DROP)
	    {
	      pkts_dropped++;
	    }
	  /*
	   * verify speculative enqueues, maybe switch current
	   * next frame
	   */
	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next,
					   n_left_to_next, bi0, bi1, next0,
					   next1);
	}

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  u32 next0 = HICNPG_INTEREST_NEXT_DROP;
	  u32 sw_if_index0;
	  u8 isv6_0;

	  /* speculatively enqueue b0 to the current next frame */
	  bi0 = from[0];
	  to_next[0] = bi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;

	  b0 = vlib_get_buffer (vm, bi0);

	  hicn_buffer_set_flags (b0, HICN_BUFFER_FLAGS_FROM_PG);

	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = hpgm->sw_if;

	  /* Check icn packets, locate names */
	  if (hicn_interest_parse_pkt (b0) == HICN_ERROR_NONE)
	    {
	      /* this node grabs only interests */
	      isv6_0 = hicn_buffer_is_v6 (b0);

	      /* Increment the appropriate message counter */
	      interest_msgs_generated++;

	      iface = (hpgm->index_ifaces % hpgm->n_ifaces);

	      /* Rewrite and send */
	      isv6_0 ?
		      hicn_rewrite_interestv6 (
		  vm, b0, (hpgm->index / hpgm->n_flows) % hpgm->max_seq_number,
		  hpgm->interest_lifetime, hpgm->index % hpgm->n_flows,
		  iface) :
		      hicn_rewrite_interestv4 (
		  vm, b0, (hpgm->index / hpgm->n_flows) % hpgm->max_seq_number,
		  hpgm->interest_lifetime, hpgm->index % hpgm->n_flows, iface);

	      hpgm->index_ifaces++;
	      if (iface == (hpgm->n_ifaces - 1))
		hpgm->index++;

	      next0 = isv6_0 ? HICNPG_INTEREST_NEXT_V6_LOOKUP :
				     HICNPG_INTEREST_NEXT_V4_LOOKUP;
	    }
	  /* Send pkt to ip lookup */
	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      hicnpg_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
	      t->pkt_type = pkt_type0;
	      t->msg_type = msg_type0;
	      t->sw_if_index = sw_if_index0;
	      t->next_index = next0;
	    }
	  pkts_processed += 1;

	  if (next0 == HICNPG_INTEREST_NEXT_DROP)
	    {
	      pkts_dropped++;
	    }
	  /*
	   * verify speculative enqueue, maybe switch current
	   * next frame
	   */
	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, bi0, next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_node_increment_counter (vm, hicn_pg_interest_node.index,
			       HICNPG_ERROR_PROCESSED, pkts_processed);
  vlib_node_increment_counter (vm, hicn_pg_interest_node.index,
			       HICNPG_ERROR_DROPPED, pkts_dropped);
  vlib_node_increment_counter (vm, hicn_pg_interest_node.index,
			       HICNPG_ERROR_INTEREST_MSGS_GENERATED,
			       interest_msgs_generated);

  return (frame->n_vectors);
}

void
hicn_rewrite_interestv4 (vlib_main_t *vm, vlib_buffer_t *b0, u32 seq_number,
			 u16 interest_lifetime, u32 next_flow, u32 iface)
{
  hicn_header_t *h0 = vlib_buffer_get_current (b0);

  /* Generate the right src and dst corresponding to flow and iface */
  ip46_address_t src_addr = {
    .ip4 = hicnpg_main.pgen_clt_src_addr.ip4,
  };
  hicn_name_t dst_name = {
    .prefix.ip4 = hicnpg_main.pgen_clt_hicn_name->fp_addr.ip4,
    .suffix = seq_number,
  };

  src_addr.ip4.as_u32 += clib_host_to_net_u32 (iface);
  dst_name.prefix.ip4.as_u32 += clib_net_to_host_u32 (next_flow);

  /* Update locator and name */
  hicn_type_t type = hicn_get_buffer (b0)->type;
  HICN_OPS4->set_interest_locator (type, &h0->protocol, &src_addr);
  HICN_OPS4->set_interest_name (type, &h0->protocol, &dst_name);

  /* Update lifetime  (currently L4 checksum is not updated) */
  HICN_OPS4->set_lifetime (type, &h0->protocol, interest_lifetime);

  /* Update checksums */
  HICN_OPS4->update_checksums (type, &h0->protocol, 0, 0);
}

/**
 * @brief Rewrite the IPv6 header as the next generated packet
 *
 * Set up a name prefix
 *  - etiher generate interest in which the name varies only after the prefix
 *  (inc : seq_number), then the flow acts on the prefix (CHECK)
 *  seq_number => TCP, FLOW =>
 *
 *  SRC : pgen_clt_src_addr.ip6 DST = generate name (pgen_clt_hicn_name.ip6)
 *  ffff:ffff:ffff:ffff         ffff:ffff:ffff:ffff
 *                 \__/                        \__/
 *                 +iface                      + flow
 *  Source is used to emulate different consumers.
 *    FIXME iface is ill-named, better name it consumer id
 *  Destination is used to iterate on the content.
 */
void
hicn_rewrite_interestv6 (vlib_main_t *vm, vlib_buffer_t *b0, u32 seq_number,
			 u16 interest_lifetime, u32 next_flow, u32 iface)
{
  hicn_header_t *h0 = vlib_buffer_get_current (b0);

  /* Generate the right src and dst corresponding to flow and iface */
  ip46_address_t src_addr = {
    .ip6 = hicnpg_main.pgen_clt_src_addr.ip6,
  };
  hicn_name_t dst_name = {
    .prefix.ip6 = hicnpg_main.pgen_clt_hicn_name->fp_addr.ip6,
    .suffix = seq_number,
  };
  src_addr.ip6.as_u32[3] += clib_host_to_net_u32 (iface);
  dst_name.prefix.ip6.as_u32[3] += clib_net_to_host_u32 (next_flow);

  /* Update locator and name */
  hicn_type_t type = hicn_get_buffer (b0)->type;
  HICN_OPS6->set_interest_locator (type, &h0->protocol, &src_addr);
  HICN_OPS6->set_interest_name (type, &h0->protocol, &dst_name);

  /* Update lifetime */
  HICN_OPS6->set_lifetime (type, &h0->protocol, interest_lifetime);

  /* Update checksums */
  calculate_tcp_checksum_v6 (vm, b0);
}

void
calculate_tcp_checksum_v4 (vlib_main_t *vm, vlib_buffer_t *b0)
{
  ip4_header_t *ip0;
  tcp_header_t *tcp0;
  ip_csum_t sum0;
  u32 tcp_len0;

  ip0 = (ip4_header_t *) (vlib_buffer_get_current (b0));
  tcp0 =
    (tcp_header_t *) (vlib_buffer_get_current (b0) + sizeof (ip4_header_t));
  tcp_len0 = clib_net_to_host_u16 (ip0->length) - sizeof (ip4_header_t);

  /* Initialize checksum with header. */
  if (BITS (sum0) == 32)
    {
      sum0 = clib_mem_unaligned (&ip0->src_address, u32);
      sum0 =
	ip_csum_with_carry (sum0, clib_mem_unaligned (&ip0->dst_address, u32));
    }
  else
    sum0 = clib_mem_unaligned (&ip0->src_address, u64);

  sum0 = ip_csum_with_carry (
    sum0, clib_host_to_net_u32 (tcp_len0 + (ip0->protocol << 16)));

  /* Invalidate possibly old checksum. */
  tcp0->checksum = 0;

  u32 tcp_offset = sizeof (ip4_header_t);
  sum0 = ip_incremental_checksum_buffer (vm, b0, tcp_offset, tcp_len0, sum0);

  tcp0->checksum = ~ip_csum_fold (sum0);
}

void
calculate_tcp_checksum_v6 (vlib_main_t *vm, vlib_buffer_t *b0)
{
  ip6_header_t *ip0;
  tcp_header_t *tcp0;
  ip_csum_t sum0;
  u32 tcp_len0;

  ip0 = (ip6_header_t *) (vlib_buffer_get_current (b0));
  tcp0 =
    (tcp_header_t *) (vlib_buffer_get_current (b0) + sizeof (ip6_header_t));
  tcp_len0 = clib_net_to_host_u16 (ip0->payload_length);

  /* Initialize checksum with header. */
  if (BITS (sum0) == 32)
    {
      sum0 = clib_mem_unaligned (&ip0->src_address, u32);
      sum0 =
	ip_csum_with_carry (sum0, clib_mem_unaligned (&ip0->dst_address, u32));
    }
  else
    sum0 = clib_mem_unaligned (&ip0->src_address, u64);

  sum0 = ip_csum_with_carry (
    sum0, clib_host_to_net_u32 (tcp_len0 + (ip0->protocol << 16)));

  /* Invalidate possibly old checksum. */
  tcp0->checksum = 0;

  u32 tcp_offset = sizeof (ip6_header_t);
  sum0 = ip_incremental_checksum_buffer (vm, b0, tcp_offset, tcp_len0, sum0);

  tcp0->checksum = ~ip_csum_fold (sum0);
}

VLIB_REGISTER_NODE (hicn_pg_interest_node) = {
  .function = hicnpg_client_interest_node_fn,
  .name = "hicnpg-interest",
  .vector_size = sizeof (u32),
  .format_trace = format_hicnpg_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (hicnpg_error_strings),
  .error_strings = hicnpg_error_strings,
  .n_next_nodes = HICNPG_N_NEXT,
  .next_nodes = { [HICNPG_INTEREST_NEXT_V4_LOOKUP] = "ip4-lookup",
		  [HICNPG_INTEREST_NEXT_V6_LOOKUP] = "ip6-lookup",
		  [HICNPG_INTEREST_NEXT_DROP] = "error-drop" },
};

/*
 * Next graph nodes, which reference the list in the actual registration
 * block below
 */
typedef enum
{
  HICNPG_DATA_NEXT_DROP,
  HICNPG_DATA_NEXT_LOOKUP4,
  HICNPG_DATA_NEXT_LOOKUP6,
  HICNPG_DATA_N_NEXT,
} hicnpg_data_next_t;

/* Trace context struct */
typedef struct
{
  u32 next_index;
  u32 sw_if_index;
  u8 pkt_type;
  u16 msg_type;
} icnpg_data_trace_t;

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

  s = format (s, "HICNPG: pkt: %d, msg %d, sw_if_index %d, next index %d",
	      (int) t->pkt_type, (int) t->msg_type, t->sw_if_index,
	      t->next_index);
  return (s);
}

/*
 * Node function for the icn packet-generator client. The goal here is to
 * manipulate/tweak a stream of packets that have been injected by the vpp
 * packet generator to generate icn request traffic.
 */
static uword
hicnpg_client_data_node_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
			    vlib_frame_t *frame)
{
  u32 n_left_from, *from, *to_next;
  hicnpg_data_next_t next_index;
  u32 pkts_processed = 0;
  u32 content_msgs_received = 0;
  u32 bi0, bi1;
  vlib_buffer_t *b0, *b1;
  u8 pkt_type0 = 0, pkt_type1 = 0;
  u16 msg_type0 = 1, msg_type1 = 1;

  from = vlib_frame_vector_args (frame);
  n_left_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 >= 4 && n_left_to_next >= 2)
	{
	  u32 next0 = HICNPG_DATA_NEXT_DROP;
	  u32 next1 = HICNPG_DATA_NEXT_DROP;
	  u32 sw_if_index0, sw_if_index1;

	  /* Prefetch next iteration. */
	  {
	    vlib_buffer_t *p2, *p3;

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

	    vlib_prefetch_buffer_header (p2, LOAD);
	    vlib_prefetch_buffer_header (p3, LOAD);

	    CLIB_PREFETCH (p2->data, (2 * CLIB_CACHE_LINE_BYTES), STORE);
	    CLIB_PREFETCH (p3->data, (2 * CLIB_CACHE_LINE_BYTES), STORE);
	  }

	  /*
	   * speculatively enqueue b0 and b1 to the current
	   * next frame
	   */
	  to_next[0] = bi0 = from[0];
	  to_next[1] = bi1 = from[1];
	  from += 2;
	  to_next += 2;
	  n_left_from -= 2;
	  n_left_to_next -= 2;

	  b0 = vlib_get_buffer (vm, bi0);
	  b1 = vlib_get_buffer (vm, bi1);

	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
	  sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];

	  next0 = HICNPG_DATA_NEXT_DROP;
	  next1 = HICNPG_DATA_NEXT_DROP;

	  // Increment counter
	  content_msgs_received += 2;

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
	    {
	      if (b0->flags & VLIB_BUFFER_IS_TRACED)
		{
		  icnpg_data_trace_t *t =
		    vlib_add_trace (vm, node, b0, sizeof (*t));
		  t->pkt_type = pkt_type0;
		  t->msg_type = msg_type0;
		  t->sw_if_index = sw_if_index0;
		  t->next_index = next0;
		}
	      if (b1->flags & VLIB_BUFFER_IS_TRACED)
		{
		  icnpg_data_trace_t *t =
		    vlib_add_trace (vm, node, b1, sizeof (*t));
		  t->pkt_type = pkt_type1;
		  t->msg_type = msg_type1;
		  t->sw_if_index = sw_if_index1;
		  t->next_index = next1;
		}
	    }

	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next,
					   n_left_to_next, bi0, bi1, next0,
					   next1);
	  pkts_processed += 2;
	}

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  u32 next0 = HICNPG_DATA_NEXT_DROP;
	  u32 sw_if_index0;

	  /* speculatively enqueue b0 to the current next frame */
	  bi0 = from[0];
	  to_next[0] = bi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;

	  b0 = vlib_get_buffer (vm, bi0);

	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];

	  next0 = HICNPG_DATA_NEXT_DROP;

	  // Increment a counter
	  content_msgs_received += 1;

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      icnpg_data_trace_t *t =
		vlib_add_trace (vm, node, b0, sizeof (*t));
	      t->pkt_type = pkt_type0;
	      t->msg_type = msg_type0;
	      t->sw_if_index = sw_if_index0;
	      t->next_index = next0;
	    }

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

	  pkts_processed++;
	}
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_node_increment_counter (vm, hicn_pg_data_node.index,
			       HICNPG_ERROR_PROCESSED, pkts_processed);
  vlib_node_increment_counter (vm, hicn_pg_data_node.index,
			       HICNPG_ERROR_CONTENT_MSGS_RECEIVED,
			       content_msgs_received);
  return (frame->n_vectors);
}

VLIB_REGISTER_NODE(hicn_pg_data_node) =
{
  .function = hicnpg_client_data_node_fn,
  .name = "hicnpg-data",
  .vector_size = sizeof(u32),
  .format_trace = format_hicnpg_data_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(hicnpg_error_strings),
  .error_strings = hicnpg_error_strings,
  .n_next_nodes = HICNPG_DATA_N_NEXT,
  .next_nodes =
  {
   [HICNPG_DATA_NEXT_DROP] = "error-drop",
   [HICNPG_DATA_NEXT_LOOKUP4] = "ip4-lookup",
   [HICNPG_DATA_NEXT_LOOKUP6] = "ip6-lookup",
  },
};

VNET_FEATURE_INIT (hicn_data_input_ip4_arc, static) = {
  .arc_name = "ip4-unicast",
  .node_name = "hicnpg-data",
  .runs_before = VNET_FEATURES ("ip4-inacl"),
};

VNET_FEATURE_INIT (hicn_data_input_ip6_arc, static) = {
  .arc_name = "ip6-unicast",
  .node_name = "hicnpg-data",
  .runs_before = VNET_FEATURES ("ip6-inacl"),
};

/*
 * End of packet-generator client node
 */

/*
 * Beginning of packet-generation server node
 */

/* Registration struct for a graph node */
vlib_node_registration_t hicn_pg_server_node;

/* Stats, which end up called "error" even though they aren't... */
#define foreach_icnpg_server_error                                            \
  _ (PROCESSED, "hICN PG Server packets processed")                           \
  _ (DROPPED, "hICN PG Server packets dropped")

typedef enum
{
#define _(sym, str) HICNPG_SERVER_ERROR_##sym,
  foreach_icnpg_server_error
#undef _
    HICNPG_SERVER_N_ERROR,
} icnpg_server_error_t;

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

/*
 * Next graph nodes, which reference the list in the actual registration
 * block below
 */
typedef enum
{
  HICNPG_SERVER_NEXT_V4_LOOKUP,
  HICNPG_SERVER_NEXT_V6_LOOKUP,
  HICNPG_SERVER_NEXT_DROP,
  HICNPG_SERVER_N_NEXT,
} icnpg_server_next_t;

/* Trace context struct */
typedef struct
{
  u32 next_index;
  u32 sw_if_index;
  u8 pkt_type;
  u16 msg_type;
} hicnpg_server_trace_t;

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

  s = format (
    s, "HICNPG SERVER: pkt: %d, msg %d, sw_if_index %d, next index %d",
    (int) t->pkt_type, (int) t->msg_type, t->sw_if_index, t->next_index);
  return (s);
}

/*
 * Node function for the icn packet-generator server.
 */
static uword
hicnpg_node_server_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
		       vlib_frame_t *frame, int isv6)
{
  u32 n_left_from, *from, *to_next;
  icnpg_server_next_t next_index;
  u32 pkts_processed = 0, pkts_dropped = 0;
  u32 bi0, bi1;
  vlib_buffer_t *b0, *b1;
  u8 pkt_type0 = 0, pkt_type1 = 0;
  u16 msg_type0 = 0, msg_type1 = 0;

  from = vlib_frame_vector_args (frame);

  n_left_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 >= 4 && n_left_to_next >= 2)
	{
	  u32 next0 = HICNPG_SERVER_NEXT_DROP;
	  u32 next1 = HICNPG_SERVER_NEXT_DROP;
	  u32 sw_if_index0, sw_if_index1;
	  u32 hpgi0, hpgi1;
	  hicnpg_server_t *hpg0, *hpg1;

	  /* Prefetch next iteration. */
	  {
	    vlib_buffer_t *p2, *p3;

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

	    vlib_prefetch_buffer_header (p2, LOAD);
	    vlib_prefetch_buffer_header (p3, LOAD);

	    CLIB_PREFETCH (p2->data, (2 * CLIB_CACHE_LINE_BYTES), STORE);
	    CLIB_PREFETCH (p3->data, (2 * CLIB_CACHE_LINE_BYTES), STORE);
	  }

	  /*
	   * speculatively enqueue b0 and b1 to the current
	   * next frame
	   */
	  to_next[0] = bi0 = from[0];
	  to_next[1] = bi1 = from[1];
	  from += 2;
	  to_next += 2;
	  n_left_from -= 2;
	  n_left_to_next -= 2;

	  b0 = vlib_get_buffer (vm, bi0);
	  b1 = vlib_get_buffer (vm, bi1);

	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
	  sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];

	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
	  vnet_buffer (b1)->sw_if_index[VLIB_TX] = ~0;

	  hpgi0 = vnet_buffer (b0)->ip.adj_index[VLIB_TX];
	  hpgi1 = vnet_buffer (b1)->ip.adj_index[VLIB_TX];

	  hpg0 = hicnpg_server_get (hpgi0);
	  hpg1 = hicnpg_server_get (hpgi1);

	  if (hicn_interest_parse_pkt (b0) == HICN_ERROR_NONE)
	    {
	      vlib_buffer_t *rb = NULL;
	      rb = vlib_get_buffer (vm, hpg0->buffer_index);

	      isv6 ? convert_interest_to_data_v6 (vm, b0, rb, bi0) :
			   convert_interest_to_data_v4 (vm, b0, rb, bi0);

	      next0 = isv6 ? HICNPG_SERVER_NEXT_V6_LOOKUP :
				   HICNPG_SERVER_NEXT_V4_LOOKUP;
	    }

	  if (hicn_interest_parse_pkt (b1) == HICN_ERROR_NONE)
	    {
	      vlib_buffer_t *rb = NULL;
	      rb = vlib_get_buffer (vm, hpg1->buffer_index);

	      isv6 ? convert_interest_to_data_v6 (vm, b1, rb, bi1) :
			   convert_interest_to_data_v4 (vm, b1, rb, bi1);

	      next1 = isv6 ? HICNPG_SERVER_NEXT_V6_LOOKUP :
				   HICNPG_SERVER_NEXT_V4_LOOKUP;
	    }
	  pkts_processed += 2;

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
	    {
	      if (b0->flags & VLIB_BUFFER_IS_TRACED)
		{
		  hicnpg_server_trace_t *t =
		    vlib_add_trace (vm, node, b0, sizeof (*t));
		  t->pkt_type = pkt_type0;
		  t->msg_type = msg_type0;
		  t->sw_if_index = sw_if_index0;
		  t->next_index = next0;
		}
	      if (b1->flags & VLIB_BUFFER_IS_TRACED)
		{
		  hicnpg_server_trace_t *t =
		    vlib_add_trace (vm, node, b1, sizeof (*t));
		  t->pkt_type = pkt_type1;
		  t->msg_type = msg_type1;
		  t->sw_if_index = sw_if_index1;
		  t->next_index = next1;
		}
	    }
	  if (next0 == HICNPG_SERVER_NEXT_DROP)
	    {
	      pkts_dropped++;
	    }
	  if (next1 == HICNPG_SERVER_NEXT_DROP)
	    {
	      pkts_dropped++;
	    }
	  /*
	   * verify speculative enqueues, maybe switch current
	   * next frame
	   */
	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next,
					   n_left_to_next, bi0, bi1, next0,
					   next1);
	}

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  u32 next0 = HICNPG_SERVER_NEXT_DROP;
	  u32 sw_if_index0 = ~0;
	  u32 hpgi0;
	  hicnpg_server_t *hpg0;

	  /* speculatively enqueue b0 to the current next frame */
	  bi0 = from[0];
	  to_next[0] = bi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;

	  b0 = vlib_get_buffer (vm, bi0);

	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;

	  hpgi0 = vnet_buffer (b0)->ip.adj_index[VLIB_TX];
	  hpg0 = hicnpg_server_get (hpgi0);

	  if (hicn_interest_parse_pkt (b0) == HICN_ERROR_NONE)
	    {
	      /* this node grabs only interests */
	      vlib_buffer_t *rb = NULL;
	      rb = vlib_get_buffer (vm, hpg0->buffer_index);

	      isv6 ? convert_interest_to_data_v6 (vm, b0, rb, bi0) :
			   convert_interest_to_data_v4 (vm, b0, rb, bi0);

	      next0 = isv6 ? HICNPG_SERVER_NEXT_V6_LOOKUP :
				   HICNPG_SERVER_NEXT_V4_LOOKUP;
	    }
	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (b0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      hicnpg_server_trace_t *t =
		vlib_add_trace (vm, node, b0, sizeof (*t));
	      t->pkt_type = pkt_type0;
	      t->msg_type = msg_type0;
	      t->sw_if_index = sw_if_index0;
	      t->next_index = next0;
	    }
	  pkts_processed += 1;

	  if (next0 == HICNPG_SERVER_NEXT_DROP)
	    {
	      pkts_dropped++;
	    }
	  /*
	   * verify speculative enqueue, maybe switch current
	   * next frame
	   */
	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, bi0, next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_node_increment_counter (vm, hicn_pg_server_node.index,
			       HICNPG_SERVER_ERROR_PROCESSED, pkts_processed);
  vlib_node_increment_counter (vm, hicn_pg_server_node.index,
			       HICNPG_SERVER_ERROR_DROPPED, pkts_dropped);

  return (frame->n_vectors);
}

void
convert_interest_to_data_v4 (vlib_main_t *vm, vlib_buffer_t *b0,
			     vlib_buffer_t *rb, u32 bi0)
{
  hicn_header_t *h0 = vlib_buffer_get_current (b0);

  /* Get the packet length */
  u16 pkt_len = clib_net_to_host_u16 (h0->v4.ip.len);

  /*
   * Rule of thumb: We want the size of the IP packet to be <= 1500 bytes
   */
  u16 bytes_to_copy = rb->current_length;
  if ((bytes_to_copy + pkt_len) > 1500)
    {
      bytes_to_copy = 1500 - pkt_len;
    }
  /* Add content to the data packet */
  vlib_buffer_add_data (vm, &bi0, rb->data, bytes_to_copy);

  b0 = vlib_get_buffer (vm, bi0);

  h0 = vlib_buffer_get_current (b0);

  ip4_address_t src_addr = h0->v4.ip.saddr;
  h0->v4.ip.saddr = h0->v4.ip.daddr;
  h0->v4.ip.daddr = src_addr;

  h0->v4.ip.len = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
  h0->v4.ip.csum = ip4_header_checksum ((ip4_header_t *) &(h0->v4.ip));
  calculate_tcp_checksum_v4 (vm, b0);
}

void
convert_interest_to_data_v6 (vlib_main_t *vm, vlib_buffer_t *b0,
			     vlib_buffer_t *rb, u32 bi0)
{
  hicn_header_t *h0 = vlib_buffer_get_current (b0);

  /* Get the packet length */
  uint16_t pkt_len =
    clib_net_to_host_u16 (h0->v6.ip.len) + sizeof (ip6_header_t);

  /*
   * Figure out how many bytes we can add to the content
   *
   * Rule of thumb: We want the size of the IP packet to be <= 1400 bytes
   */
  u16 bytes_to_copy = rb->current_length;
  if ((bytes_to_copy + pkt_len) > 1500)
    {
      bytes_to_copy = 1500 - pkt_len;
    }
  /* Add content to the data packet */
  vlib_buffer_add_data (vm, &bi0, rb->data, bytes_to_copy);

  b0 = vlib_get_buffer (vm, bi0);

  h0 = vlib_buffer_get_current (b0);
  ip6_address_t src_addr = h0->v6.ip.saddr;
  h0->v6.ip.saddr = h0->v6.ip.daddr;
  h0->v6.ip.daddr = src_addr;

  h0->v6.ip.len = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0) -
					sizeof (ip6_header_t));
  h0->v6.tcp.data_offset_and_reserved |= 0x0f;
  h0->v6.tcp.urg_ptr = htons (0xffff);

  calculate_tcp_checksum_v6 (vm, b0);
}

VLIB_NODE_FN (hicn_pg_server6_node)
(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
{
  return hicnpg_node_server_fn (vm, node, frame, 1 /* is_v6 */);
}

VLIB_NODE_FN (hicn_pg_server4_node)
(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
{
  return hicnpg_node_server_fn (vm, node, frame, 0 /* is_v6 */);
}

VLIB_REGISTER_NODE(hicn_pg_server6_node) =
{
  .name = "hicnpg-server-6",
  .vector_size = sizeof(u32),
  .format_trace = format_icnpg_server_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(icnpg_server_error_strings),
  .error_strings = icnpg_server_error_strings,
  .n_next_nodes = HICNPG_SERVER_N_NEXT,
  /* edit / add dispositions here */
  .next_nodes =
  {
    [HICNPG_SERVER_NEXT_V4_LOOKUP] = "ip4-lookup",
    [HICNPG_SERVER_NEXT_V6_LOOKUP] = "ip6-lookup",
    [HICNPG_SERVER_NEXT_DROP] = "error-drop",
  },
};

VLIB_REGISTER_NODE(hicn_pg_server4_node) =
{
  .name = "hicnpg-server-4",
  .vector_size = sizeof(u32),
  .format_trace = format_icnpg_server_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(icnpg_server_error_strings),
  .error_strings = icnpg_server_error_strings,
  .n_next_nodes = HICNPG_SERVER_N_NEXT,
  /* edit / add dispositions here */
  .next_nodes =
  {
    [HICNPG_SERVER_NEXT_V4_LOOKUP] = "ip4-lookup",
    [HICNPG_SERVER_NEXT_V6_LOOKUP] = "ip6-lookup",
    [HICNPG_SERVER_NEXT_DROP] = "error-drop",
  },
};

/*
 * End of packet-generator server node
 */