/*
 * 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.
 */
/**
 *  @file
 *  @brief Functions for encapsulating VXLAN GPE tunnels
 *
*/
#include <vppinfra/error.h>
#include <vppinfra/hash.h>
#include <vnet/vnet.h>
#include <vnet/ip/ip.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/vxlan-gpe/vxlan_gpe.h>

/** Statistics (not really errors) */
#define foreach_vxlan_gpe_encap_error    \
_(ENCAPSULATED, "good packets encapsulated")

/**
 * @brief VXLAN GPE encap error strings
 */
static char *vxlan_gpe_encap_error_strings[] = {
#define _(sym,string) string,
  foreach_vxlan_gpe_encap_error
#undef _
};

/**
 * @brief Struct for VXLAN GPE errors/counters
 */
typedef enum
{
#define _(sym,str) VXLAN_GPE_ENCAP_ERROR_##sym,
  foreach_vxlan_gpe_encap_error
#undef _
    VXLAN_GPE_ENCAP_N_ERROR,
} vxlan_gpe_encap_error_t;

/**
 * @brief Struct for tracing VXLAN GPE encapsulated packets
 */
typedef struct
{
  u32 tunnel_index;
} vxlan_gpe_encap_trace_t;

/**
 * @brief Trace of packets encapsulated in VXLAN GPE
 *
 * @param *s
 * @param *args
 *
 * @return *s
 *
 */
u8 *
format_vxlan_gpe_encap_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 *);
  vxlan_gpe_encap_trace_t *t = va_arg (*args, vxlan_gpe_encap_trace_t *);

  s = format (s, "VXLAN-GPE-ENCAP: tunnel %d", t->tunnel_index);
  return s;
}

/**
 * @brief Instantiates UDP + VXLAN-GPE header then set next node to IP4|6 lookup
 *
 * @param *ngm
 * @param *b0
 * @param *t0 contains rewrite header
 * @param *next0 relative index of next dispatch function (next node)
 * @param is_v4 Is this IPv4? (or IPv6)
 *
 */
always_inline void
vxlan_gpe_encap_one_inline (vxlan_gpe_main_t * ngm, vlib_buffer_t * b0,
			    vxlan_gpe_tunnel_t * t0, u32 * next0, u8 is_v4)
{
  ASSERT (sizeof (ip4_vxlan_gpe_header_t) == 36);
  ASSERT (sizeof (ip6_vxlan_gpe_header_t) == 56);

  ip_udp_encap_one (ngm->vlib_main, b0, t0->rewrite, t0->rewrite_size, is_v4);
  next0[0] = t0->encap_next_node;
}

/**
 * @brief Instantiates UDP + VXLAN-GPE header then set next node to IP4|6 lookup for two packets
 *
 * @param *ngm
 * @param *b0 Packet0
 * @param *b1 Packet1
 * @param *t0 contains rewrite header for Packet0
 * @param *t1 contains rewrite header for Packet1
 * @param *next0 relative index of next dispatch function (next node) for Packet0
 * @param *next1 relative index of next dispatch function (next node) for Packet1
 * @param is_v4 Is this IPv4? (or IPv6)
 *
 */
always_inline void
vxlan_gpe_encap_two_inline (vxlan_gpe_main_t * ngm, vlib_buffer_t * b0,
			    vlib_buffer_t * b1, vxlan_gpe_tunnel_t * t0,
			    vxlan_gpe_tunnel_t * t1, u32 * next0,
			    u32 * next1, u8 is_v4)
{
  ASSERT (sizeof (ip4_vxlan_gpe_header_t) == 36);
  ASSERT (sizeof (ip6_vxlan_gpe_header_t) == 56);

  ip_udp_encap_one (ngm->vlib_main, b0, t0->rewrite, t0->rewrite_size, is_v4);
  ip_udp_encap_one (ngm->vlib_main, b1, t1->rewrite, t1->rewrite_size, is_v4);
  next0[0] = next1[0] = t0->encap_next_node;
}

/**
 * @brief Common processing for IPv4 and IPv6 VXLAN GPE encap dispatch functions
 *
 * It is worth noting that other than trivial UDP forwarding (transit), VXLAN GPE
 * tunnels are "establish local". This means that we don't have a TX interface as yet
 * as we need to look up where the outer-header dest is. By setting the TX index in the
 * buffer metadata to the encap FIB, we can do a lookup to get the adjacency and real TX.
 *
 *      vnet_buffer(b0)->sw_if_index[VLIB_TX] = t0->encap_fib_index;
 *
 * @node vxlan-gpe-input
 * @param *vm
 * @param *node
 * @param *from_frame
 *
 * @return from_frame->n_vectors
 *
 */
static uword
vxlan_gpe_encap (vlib_main_t * vm,
		 vlib_node_runtime_t * node, vlib_frame_t * from_frame)
{
  u32 n_left_from, next_index, *from, *to_next;
  vxlan_gpe_main_t *ngm = &vxlan_gpe_main;
  vnet_main_t *vnm = ngm->vnet_main;
  vnet_interface_main_t *im = &vnm->interface_main;
  u32 pkts_encapsulated = 0;
  u32 thread_index = vm->thread_index;
  u32 stats_sw_if_index, stats_n_packets, stats_n_bytes;

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

  next_index = node->cached_next_index;
  stats_sw_if_index = node->runtime_data[0];
  stats_n_packets = stats_n_bytes = 0;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;
      u32 sw_if_index0 = ~0, sw_if_index1 = ~0, len0, len1;
      vnet_hw_interface_t *hi0, *hi1;
      vxlan_gpe_tunnel_t *t0 = NULL, *t1 = NULL;
      u8 is_ip4_0 = 0, is_ip4_1 = 0;

      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 bi0, bi1;
	  vlib_buffer_t *b0, *b1;
	  u32 next0, next1;

	  next0 = next1 = VXLAN_GPE_ENCAP_NEXT_IP4_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, LOAD);
	    vlib_prefetch_buffer_header (p3, LOAD);

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

	  bi0 = from[0];
	  bi1 = from[1];
	  to_next[0] = bi0;
	  to_next[1] = bi1;
	  from += 2;
	  to_next += 2;
	  n_left_to_next -= 2;
	  n_left_from -= 2;

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

	  /* get the flag "is_ip4" */
	  if (sw_if_index0 != vnet_buffer (b0)->sw_if_index[VLIB_TX])
	    {
	      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];
	      hi0 =
		vnet_get_sup_hw_interface (vnm,
					   vnet_buffer (b0)->sw_if_index
					   [VLIB_TX]);
	      t0 = pool_elt_at_index (ngm->tunnels, hi0->dev_instance);
	      is_ip4_0 = (t0->flags & VXLAN_GPE_TUNNEL_IS_IPV4);
	    }

	  /* get the flag "is_ip4" */
	  if (sw_if_index1 != vnet_buffer (b1)->sw_if_index[VLIB_TX])
	    {
	      if (sw_if_index0 == vnet_buffer (b1)->sw_if_index[VLIB_TX])
		{
		  sw_if_index1 = sw_if_index0;
		  hi1 = hi0;
		  t1 = t0;
		  is_ip4_1 = is_ip4_0;
		}
	      else
		{
		  sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_TX];
		  hi1 =
		    vnet_get_sup_hw_interface (vnm,
					       vnet_buffer (b1)->sw_if_index
					       [VLIB_TX]);
		  t1 = pool_elt_at_index (ngm->tunnels, hi1->dev_instance);
		  is_ip4_1 = (t1->flags & VXLAN_GPE_TUNNEL_IS_IPV4);
		}
	    }

	  if (PREDICT_TRUE (is_ip4_0 == is_ip4_1))
	    {
	      vxlan_gpe_encap_two_inline (ngm, b0, b1, t0, t1, &next0, &next1,
					  is_ip4_0);
	    }
	  else
	    {
	      vxlan_gpe_encap_one_inline (ngm, b0, t0, &next0, is_ip4_0);
	      vxlan_gpe_encap_one_inline (ngm, b1, t1, &next1, is_ip4_1);
	    }

	  /* Reset to look up tunnel partner in the configured FIB */
	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = t0->encap_fib_index;
	  vnet_buffer (b1)->sw_if_index[VLIB_TX] = t1->encap_fib_index;
	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = sw_if_index0;
	  vnet_buffer (b1)->sw_if_index[VLIB_RX] = sw_if_index1;
	  pkts_encapsulated += 2;

	  len0 = vlib_buffer_length_in_chain (vm, b0);
	  len1 = vlib_buffer_length_in_chain (vm, b1);
	  stats_n_packets += 2;
	  stats_n_bytes += len0 + len1;

	  /* Batch stats increment on the same vxlan tunnel so counter is not
	     incremented per packet. Note stats are still incremented for deleted
	     and admin-down tunnel where packets are dropped. It is not worthwhile
	     to check for this rare case and affect normal path performance. */
	  if (PREDICT_FALSE ((sw_if_index0 != stats_sw_if_index)
			     || (sw_if_index1 != stats_sw_if_index)))
	    {
	      stats_n_packets -= 2;
	      stats_n_bytes -= len0 + len1;
	      if (sw_if_index0 == sw_if_index1)
		{
		  if (stats_n_packets)
		    vlib_increment_combined_counter
		      (im->combined_sw_if_counters +
		       VNET_INTERFACE_COUNTER_TX, thread_index,
		       stats_sw_if_index, stats_n_packets, stats_n_bytes);
		  stats_sw_if_index = sw_if_index0;
		  stats_n_packets = 2;
		  stats_n_bytes = len0 + len1;
		}
	      else
		{
		  vlib_increment_combined_counter (im->combined_sw_if_counters
						   +
						   VNET_INTERFACE_COUNTER_TX,
						   thread_index, sw_if_index0,
						   1, len0);
		  vlib_increment_combined_counter (im->combined_sw_if_counters
						   +
						   VNET_INTERFACE_COUNTER_TX,
						   thread_index, sw_if_index1,
						   1, len1);
		}
	    }

	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      vxlan_gpe_encap_trace_t *tr =
		vlib_add_trace (vm, node, b0, sizeof (*tr));
	      tr->tunnel_index = t0 - ngm->tunnels;
	    }

	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      vxlan_gpe_encap_trace_t *tr = vlib_add_trace (vm, node, b1,
							    sizeof (*tr));
	      tr->tunnel_index = t1 - ngm->tunnels;
	    }

	  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 bi0;
	  vlib_buffer_t *b0;
	  u32 next0 = VXLAN_GPE_ENCAP_NEXT_IP4_LOOKUP;

	  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);

	  /* get the flag "is_ip4" */
	  if (sw_if_index0 != vnet_buffer (b0)->sw_if_index[VLIB_TX])
	    {
	      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];
	      hi0 =
		vnet_get_sup_hw_interface (vnm,
					   vnet_buffer (b0)->sw_if_index
					   [VLIB_TX]);

	      t0 = pool_elt_at_index (ngm->tunnels, hi0->dev_instance);

	      is_ip4_0 = (t0->flags & VXLAN_GPE_TUNNEL_IS_IPV4);
	    }

	  vxlan_gpe_encap_one_inline (ngm, b0, t0, &next0, is_ip4_0);

	  /* Reset to look up tunnel partner in the configured FIB */
	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = t0->encap_fib_index;
	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = sw_if_index0;
	  pkts_encapsulated++;

	  len0 = vlib_buffer_length_in_chain (vm, b0);
	  stats_n_packets += 1;
	  stats_n_bytes += len0;

	  /* Batch stats increment on the same vxlan tunnel so counter is not
	   *  incremented per packet. Note stats are still incremented for deleted
	   *  and admin-down tunnel where packets are dropped. It is not worthwhile
	   *  to check for this rare case and affect normal path performance. */
	  if (PREDICT_FALSE (sw_if_index0 != stats_sw_if_index))
	    {
	      stats_n_packets -= 1;
	      stats_n_bytes -= len0;
	      if (stats_n_packets)
		vlib_increment_combined_counter (im->combined_sw_if_counters +
						 VNET_INTERFACE_COUNTER_TX,
						 thread_index,
						 stats_sw_if_index,
						 stats_n_packets,
						 stats_n_bytes);
	      stats_n_packets = 1;
	      stats_n_bytes = len0;
	      stats_sw_if_index = sw_if_index0;
	    }
	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      vxlan_gpe_encap_trace_t *tr = vlib_add_trace (vm, node, b0,
							    sizeof (*tr));
	      tr->tunnel_index = t0 - ngm->tunnels;
	    }
	  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, node->node_index,
			       VXLAN_GPE_ENCAP_ERROR_ENCAPSULATED,
			       pkts_encapsulated);
  /* Increment any remaining batch stats */
  if (stats_n_packets)
    {
      vlib_increment_combined_counter (im->combined_sw_if_counters +
				       VNET_INTERFACE_COUNTER_TX,
				       thread_index, stats_sw_if_index,
				       stats_n_packets, stats_n_bytes);
      node->runtime_data[0] = stats_sw_if_index;
    }

  return from_frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (vxlan_gpe_encap_node) = {
  .function = vxlan_gpe_encap,
  .name = "vxlan-gpe-encap",
  .vector_size = sizeof (u32),
  .format_trace = format_vxlan_gpe_encap_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = ARRAY_LEN(vxlan_gpe_encap_error_strings),
  .error_strings = vxlan_gpe_encap_error_strings,

  .n_next_nodes = VXLAN_GPE_ENCAP_N_NEXT,

  .next_nodes = {
    [VXLAN_GPE_ENCAP_NEXT_IP4_LOOKUP] = "ip4-lookup",
    [VXLAN_GPE_ENCAP_NEXT_IP6_LOOKUP] = "ip6-lookup",
    [VXLAN_GPE_ENCAP_NEXT_DROP] = "error-drop",
  },
};
/* *INDENT-ON* */


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