/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * Defines used for testing various optimisation schemes
 */

#include "map.h"
#include <vnet/ip/ip_frag.h>
#include <vnet/ip/ip4_to_ip6.h>

enum ip4_map_next_e
{
  IP4_MAP_NEXT_IP6_LOOKUP,
#ifdef MAP_SKIP_IP6_LOOKUP
  IP4_MAP_NEXT_IP6_REWRITE,
#endif
  IP4_MAP_NEXT_IP4_FRAGMENT,
  IP4_MAP_NEXT_IP6_FRAGMENT,
  IP4_MAP_NEXT_ICMP_ERROR,
  IP4_MAP_NEXT_DROP,
  IP4_MAP_N_NEXT,
};

static_always_inline u16
ip4_map_port_and_security_check (map_domain_t * d, vlib_buffer_t * b0,
				 u8 * error)
{
  u16 port;
  if (d->psid_length > 0)
    {
      ip4_header_t *ip = vlib_buffer_get_current (b0);

      if (PREDICT_FALSE
	  ((ip->ip_version_and_header_length != 0x45)
	   || clib_host_to_net_u16 (ip->length) < 28))
	{
	  return 0;
	}

      port = vnet_buffer (b0)->ip.reass.l4_dst_port;

      /* Verify that port is not among the well-known ports */
      if ((d->psid_offset > 0)
	  && (clib_net_to_host_u16 (port) < (0x1 << (16 - d->psid_offset))))
	{
	  *error = MAP_ERROR_ENCAP_SEC_CHECK;
	}
      else
	{
	  return port;
	}
    }
  return (0);
}

/*
 * ip4_map_vtcfl
 */
static_always_inline u32
ip4_map_vtcfl (ip4_header_t * ip4, vlib_buffer_t * p)
{
  map_main_t *mm = &map_main;
  u8 tc = mm->tc_copy ? ip4->tos : mm->tc;
  u32 vtcfl = 0x6 << 28;
  vtcfl |= tc << 20;
  vtcfl |= vnet_buffer (p)->ip.flow_hash & 0x000fffff;

  return (clib_host_to_net_u32 (vtcfl));
}

static_always_inline bool
ip4_map_ip6_lookup_bypass (vlib_buffer_t * p0, ip4_header_t * ip)
{
#ifdef MAP_SKIP_IP6_LOOKUP
  if (FIB_NODE_INDEX_INVALID != pre_resolved[FIB_PROTOCOL_IP6].fei)
    {
      vnet_buffer (p0)->ip.adj_index[VLIB_TX] =
	pre_resolved[FIB_PROTOCOL_IP6].dpo.dpoi_index;
      return (true);
    }
#endif
  return (false);
}

/*
 * ip4_map_ttl
 */
static inline void
ip4_map_decrement_ttl (ip4_header_t * ip, u8 * error)
{
  i32 ttl = ip->ttl;

  /* Input node should have reject packets with ttl 0. */
  ASSERT (ip->ttl > 0);

  u32 checksum = ip->checksum + clib_host_to_net_u16 (0x0100);
  checksum += checksum >= 0xffff;
  ip->checksum = checksum;
  ttl -= 1;
  ip->ttl = ttl;
  *error = ttl <= 0 ? IP4_ERROR_TIME_EXPIRED : *error;

  /* Verify checksum. */
  ASSERT (ip->checksum == ip4_header_checksum (ip));
}

static u32
ip4_map_fragment (vlib_buffer_t * b, u16 mtu, bool df, u8 * error)
{
  map_main_t *mm = &map_main;

  if (mm->frag_inner)
    {
      // TODO: Fix inner fragmentation after removed inner support from ip-frag.
      ip_frag_set_vnet_buffer (b, /*sizeof (ip6_header_t), */ mtu,
			       IP4_FRAG_NEXT_IP6_LOOKUP,
			       IP_FRAG_FLAG_IP6_HEADER);
      return (IP4_MAP_NEXT_IP4_FRAGMENT);
    }
  else
    {
      if (df && !mm->frag_ignore_df)
	{
	  icmp4_error_set_vnet_buffer (b, ICMP4_destination_unreachable,
				       ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set,
				       mtu);
	  vlib_buffer_advance (b, sizeof (ip6_header_t));
	  *error = MAP_ERROR_DF_SET;
	  return (IP4_MAP_NEXT_ICMP_ERROR);
	}
      ip_frag_set_vnet_buffer (b, mtu, IP6_FRAG_NEXT_IP6_LOOKUP,
			       IP_FRAG_FLAG_IP6_HEADER);
      return (IP4_MAP_NEXT_IP6_FRAGMENT);
    }
}

/*
 * ip4_map
 */
static uword
ip4_map (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
  vlib_node_runtime_t *error_node =
    vlib_node_get_runtime (vm, ip4_map_node.index);
  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;
  map_main_t *mm = &map_main;
  vlib_combined_counter_main_t *cm = mm->domain_counters;
  u32 thread_index = vm->thread_index;

  while (n_left_from > 0)
    {
      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      /* Dual loop */
      while (n_left_from >= 4 && n_left_to_next >= 2)
	{
	  u32 pi0, pi1;
	  vlib_buffer_t *p0, *p1;
	  map_domain_t *d0, *d1;
	  u8 error0 = MAP_ERROR_NONE, error1 = MAP_ERROR_NONE;
	  ip4_header_t *ip40, *ip41;
	  u16 port0 = 0, port1 = 0;
	  ip6_header_t *ip6h0, *ip6h1;
	  u32 map_domain_index0 = ~0, map_domain_index1 = ~0;
	  u32 next0 = IP4_MAP_NEXT_IP6_LOOKUP, next1 =
	    IP4_MAP_NEXT_IP6_LOOKUP;

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

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

	    vlib_prefetch_buffer_header (p2, STORE);
	    vlib_prefetch_buffer_header (p3, STORE);
	    /* IPv4 + 8 = 28. possibly plus -40 */
	    CLIB_PREFETCH (p2->data - 40, 68, STORE);
	    CLIB_PREFETCH (p3->data - 40, 68, STORE);
	  }

	  pi0 = to_next[0] = from[0];
	  pi1 = to_next[1] = from[1];
	  from += 2;
	  n_left_from -= 2;
	  to_next += 2;
	  n_left_to_next -= 2;

	  p0 = vlib_get_buffer (vm, pi0);
	  p1 = vlib_get_buffer (vm, pi1);
	  ip40 = vlib_buffer_get_current (p0);
	  ip41 = vlib_buffer_get_current (p1);
	  d0 =
	    ip4_map_get_domain (&ip40->dst_address, &map_domain_index0,
				&error0);
	  d1 =
	    ip4_map_get_domain (&ip41->dst_address, &map_domain_index1,
				&error1);

	  /*
	   * Shared IPv4 address
	   */
	  port0 = ip4_map_port_and_security_check (d0, p0, &error0);
	  port1 = ip4_map_port_and_security_check (d1, p1, &error1);

	  /* Decrement IPv4 TTL */
	  ip4_map_decrement_ttl (ip40, &error0);
	  ip4_map_decrement_ttl (ip41, &error1);
	  bool df0 =
	    ip40->flags_and_fragment_offset &
	    clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);
	  bool df1 =
	    ip41->flags_and_fragment_offset &
	    clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);

	  /* MAP calc */
	  u32 da40 = clib_net_to_host_u32 (ip40->dst_address.as_u32);
	  u32 da41 = clib_net_to_host_u32 (ip41->dst_address.as_u32);
	  u16 dp40 = clib_net_to_host_u16 (port0);
	  u16 dp41 = clib_net_to_host_u16 (port1);
	  u64 dal60 = map_get_pfx (d0, da40, dp40);
	  u64 dal61 = map_get_pfx (d1, da41, dp41);
	  u64 dar60 = map_get_sfx (d0, da40, dp40);
	  u64 dar61 = map_get_sfx (d1, da41, dp41);
	  if (dal60 == 0 && dar60 == 0 && error0 == MAP_ERROR_NONE)
	    error0 = MAP_ERROR_NO_BINDING;
	  if (dal61 == 0 && dar61 == 0 && error1 == MAP_ERROR_NONE)
	    error1 = MAP_ERROR_NO_BINDING;

	  /* construct ipv6 header */
	  vlib_buffer_advance (p0, -sizeof (ip6_header_t));
	  vlib_buffer_advance (p1, -sizeof (ip6_header_t));
	  ip6h0 = vlib_buffer_get_current (p0);
	  ip6h1 = vlib_buffer_get_current (p1);
	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
	  vnet_buffer (p1)->sw_if_index[VLIB_TX] = (u32) ~ 0;

	  ip6h0->ip_version_traffic_class_and_flow_label =
	    ip4_map_vtcfl (ip40, p0);
	  ip6h1->ip_version_traffic_class_and_flow_label =
	    ip4_map_vtcfl (ip41, p1);
	  ip6h0->payload_length = ip40->length;
	  ip6h1->payload_length = ip41->length;
	  ip6h0->protocol = IP_PROTOCOL_IP_IN_IP;
	  ip6h1->protocol = IP_PROTOCOL_IP_IN_IP;
	  ip6h0->hop_limit = 0x40;
	  ip6h1->hop_limit = 0x40;
	  ip6h0->src_address = d0->ip6_src;
	  ip6h1->src_address = d1->ip6_src;
	  ip6h0->dst_address.as_u64[0] = clib_host_to_net_u64 (dal60);
	  ip6h0->dst_address.as_u64[1] = clib_host_to_net_u64 (dar60);
	  ip6h1->dst_address.as_u64[0] = clib_host_to_net_u64 (dal61);
	  ip6h1->dst_address.as_u64[1] = clib_host_to_net_u64 (dar61);

	  /*
	   * Determine next node. Can be one of:
	   * ip6-lookup, ip6-rewrite, ip4-fragment, error-drop
	   */
	  if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
	    {
	      if (PREDICT_FALSE
		  (d0->mtu
		   && (clib_net_to_host_u16 (ip6h0->payload_length) +
		       sizeof (*ip6h0) > d0->mtu)))
		{
		  next0 = ip4_map_fragment (p0, d0->mtu, df0, &error0);
		}
	      else
		{
		  next0 =
		    ip4_map_ip6_lookup_bypass (p0,
					       ip40) ?
		    IP4_MAP_NEXT_IP6_REWRITE : next0;
		  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
						   thread_index,
						   map_domain_index0, 1,
						   clib_net_to_host_u16
						   (ip6h0->payload_length) +
						   40);
		}
	    }
	  else
	    {
	      next0 = IP4_MAP_NEXT_DROP;
	    }

	  /*
	   * Determine next node. Can be one of:
	   * ip6-lookup, ip6-rewrite, ip4-fragment, error-drop
	   */
	  if (PREDICT_TRUE (error1 == MAP_ERROR_NONE))
	    {
	      if (PREDICT_FALSE
		  (d1->mtu
		   && (clib_net_to_host_u16 (ip6h1->payload_length) +
		       sizeof (*ip6h1) > d1->mtu)))
		{
		  next1 = ip4_map_fragment (p1, d1->mtu, df1, &error1);
		}
	      else
		{
		  next1 =
		    ip4_map_ip6_lookup_bypass (p1,
					       ip41) ?
		    IP4_MAP_NEXT_IP6_REWRITE : next1;
		  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
						   thread_index,
						   map_domain_index1, 1,
						   clib_net_to_host_u16
						   (ip6h1->payload_length) +
						   40);
		}
	    }
	  else
	    {
	      next1 = IP4_MAP_NEXT_DROP;
	    }

	  if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      map_add_trace (vm, node, p0, map_domain_index0, port0);
	    }
	  if (PREDICT_FALSE (p1->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      map_add_trace (vm, node, p1, map_domain_index1, port0);
	    }

	  p0->error = error_node->errors[error0];
	  p1->error = error_node->errors[error1];

	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index, to_next,
					   n_left_to_next, pi0, pi1, next0,
					   next1);
	}

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  u32 pi0;
	  vlib_buffer_t *p0;
	  map_domain_t *d0;
	  u8 error0 = MAP_ERROR_NONE;
	  ip4_header_t *ip40;
	  u16 port0 = 0;
	  ip6_header_t *ip6h0;
	  u32 next0 = IP4_MAP_NEXT_IP6_LOOKUP;
	  u32 map_domain_index0 = ~0;

	  pi0 = to_next[0] = from[0];
	  from += 1;
	  n_left_from -= 1;
	  to_next += 1;
	  n_left_to_next -= 1;

	  p0 = vlib_get_buffer (vm, pi0);
	  ip40 = vlib_buffer_get_current (p0);

	  d0 =
	    ip4_map_get_domain (&ip40->dst_address, &map_domain_index0,
				&error0);
	  if (!d0)
	    {			/* Guess it wasn't for us */
	      vnet_feature_next (&next0, p0);
	      goto exit;
	    }

	  /*
	   * Shared IPv4 address
	   */
	  port0 = ip4_map_port_and_security_check (d0, p0, &error0);

	  /* Decrement IPv4 TTL */
	  ip4_map_decrement_ttl (ip40, &error0);
	  bool df0 =
	    ip40->flags_and_fragment_offset &
	    clib_host_to_net_u16 (IP4_HEADER_FLAG_DONT_FRAGMENT);

	  /* MAP calc */
	  u32 da40 = clib_net_to_host_u32 (ip40->dst_address.as_u32);
	  u16 dp40 = clib_net_to_host_u16 (port0);
	  u64 dal60 = map_get_pfx (d0, da40, dp40);
	  u64 dar60 = map_get_sfx (d0, da40, dp40);
	  if (dal60 == 0 && dar60 == 0 && error0 == MAP_ERROR_NONE)
	    error0 = MAP_ERROR_NO_BINDING;

	  /* construct ipv6 header */
	  vlib_buffer_advance (p0, -(sizeof (ip6_header_t)));
	  ip6h0 = vlib_buffer_get_current (p0);
	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = (u32) ~ 0;

	  ip6h0->ip_version_traffic_class_and_flow_label =
	    ip4_map_vtcfl (ip40, p0);
	  ip6h0->payload_length = ip40->length;
	  ip6h0->protocol = IP_PROTOCOL_IP_IN_IP;
	  ip6h0->hop_limit = 0x40;
	  ip6h0->src_address = d0->ip6_src;
	  ip6h0->dst_address.as_u64[0] = clib_host_to_net_u64 (dal60);
	  ip6h0->dst_address.as_u64[1] = clib_host_to_net_u64 (dar60);

	  /*
	   * Determine next node. Can be one of:
	   * ip6-lookup, ip6-rewrite, ip4-fragment, error-drop
	   */
	  if (PREDICT_TRUE (error0 == MAP_ERROR_NONE))
	    {
	      if (PREDICT_FALSE
		  (d0->mtu
		   && (clib_net_to_host_u16 (ip6h0->payload_length) +
		       sizeof (*ip6h0) > d0->mtu)))
		{
		  next0 = ip4_map_fragment (p0, d0->mtu, df0, &error0);
		}
	      else
		{
		  next0 =
		    ip4_map_ip6_lookup_bypass (p0,
					       ip40) ?
		    IP4_MAP_NEXT_IP6_REWRITE : next0;
		  vlib_increment_combined_counter (cm + MAP_DOMAIN_COUNTER_TX,
						   thread_index,
						   map_domain_index0, 1,
						   clib_net_to_host_u16
						   (ip6h0->payload_length) +
						   40);
		}
	    }
	  else
	    {
	      next0 = IP4_MAP_NEXT_DROP;
	    }

	  if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      map_add_trace (vm, node, p0, map_domain_index0, port0);
	    }

	  p0->error = error_node->errors[error0];
	exit:
	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, pi0, next0);
	}
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return frame->n_vectors;
}

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


/* *INDENT-OFF* */
VNET_FEATURE_INIT (ip4_map_feature, static) =
{
  .arc_name = "ip4-unicast",
  .node_name = "ip4-map",
  .runs_before = VNET_FEATURES ("ip4-flow-classify"),
  .runs_after = VNET_FEATURES("ip4-sv-reassembly-feature"),
};

VLIB_REGISTER_NODE(ip4_map_node) = {
  .function = ip4_map,
  .name = "ip4-map",
  .vector_size = sizeof(u32),
  .format_trace = format_map_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = MAP_N_ERROR,
  .error_strings = map_error_strings,

  .n_next_nodes = IP4_MAP_N_NEXT,
  .next_nodes = {
    [IP4_MAP_NEXT_IP6_LOOKUP] = "ip6-lookup",
#ifdef MAP_SKIP_IP6_LOOKUP
    [IP4_MAP_NEXT_IP6_REWRITE] = "ip6-load-balance",
#endif
    [IP4_MAP_NEXT_IP4_FRAGMENT] = "ip4-frag",
    [IP4_MAP_NEXT_IP6_FRAGMENT] = "ip6-frag",
    [IP4_MAP_NEXT_ICMP_ERROR] = "ip4-icmp-error",
    [IP4_MAP_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */

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