/*
 * l2e_node.c : l2 emulation node
 *
 * Copyright (c) 2019 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 <plugins/l2e/l2e.h>
#include <vnet/l2/l2_input.h>
#include <vnet/l2/feat_bitmap.h>

#define foreach_l2_emulation                    \
  _(IP4, "Extract IPv4")                        \
  _(IP6, "Extract IPv6")

typedef enum
{
#define _(sym,str) L2_EMULATION_ERROR_##sym,
  foreach_l2_emulation
#undef _
    L2_EMULATION_N_ERROR,
} l2_emulation_error_t;

static char *l2_emulation_error_strings[] = {
#define _(sym,string) string,
  foreach_l2_emulation
#undef _
};

typedef enum
{
#define _(sym,str) L2_EMULATION_NEXT_##sym,
  foreach_l2_emulation
#undef _
    L2_EMULATION_N_NEXT,
} l2_emulation_next_t;

/* packet trace format function */
static u8 *
format_l2_emulation_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 *);
  l2_emulation_trace_t *t = va_arg (*args, l2_emulation_trace_t *);

  s = format (s, "l2-emulation: %s", (t->extracted ? "yes" : "no"));

  return s;
}

VLIB_NODE_FN (l2_emulation_node) (vlib_main_t * vm,
				  vlib_node_runtime_t * node,
				  vlib_frame_t * frame)
{
  l2_emulation_main_t *em = &l2_emulation_main;
  u32 n_left_from, *from, *to_next;
  l2_emulation_next_t next_index;
  u32 ip4_hits = 0;
  u32 ip6_hits = 0;

  next_index = 0;
  n_left_from = frame->n_vectors;
  from = vlib_frame_vector_args (frame);

  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)
	{
	  vlib_buffer_t *b0, *b1;
	  u32 sw_if_index0, sw_if_index1;
	  u16 ether_type0, ether_type1;
	  u32 next0 = ~0, next1 = ~0;
	  u8 l2_len0, l2_len1;
	  u32 bi0, bi1;
	  u8 *h0, *h1;

	  bi0 = to_next[0] = from[0];
	  bi1 = to_next[1] = from[1];

	  from += 2;
	  n_left_from -= 2;
	  to_next += 2;
	  n_left_to_next -= 2;

	  b0 = vlib_get_buffer (vm, bi0);
	  b1 = vlib_get_buffer (vm, bi1);
	  l2_len0 = vnet_buffer (b0)->l2.l2_len;
	  l2_len1 = vnet_buffer (b1)->l2.l2_len;

	  h0 = vlib_buffer_get_current (b0);
	  h1 = vlib_buffer_get_current (b1);

	  ether_type0 = clib_net_to_host_u16 (*(u16 *) (h0 + l2_len0 - 2));
	  ether_type1 = clib_net_to_host_u16 (*(u16 *) (h1 + l2_len1 - 2));
	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
	  sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];

	  /*
	   * only extract unicast
	   */
	  if (PREDICT_TRUE (!(h0[0] & 0x1)))
	    {
	      switch (ether_type0)
		{
		case ETHERNET_TYPE_IP4:
		  ASSERT (em->l2_emulations[sw_if_index0].enabled);
		  ++ip4_hits;
		  next0 = L2_EMULATION_NEXT_IP4;
		  vlib_buffer_advance (b0, l2_len0);
		  break;
		case ETHERNET_TYPE_IP6:
		  ASSERT (em->l2_emulations[sw_if_index0].enabled);
		  ++ip6_hits;
		  next0 = L2_EMULATION_NEXT_IP6;
		  vlib_buffer_advance (b0, l2_len0);
		default:
		  break;
		}
	    }
	  if (PREDICT_TRUE (!(h1[0] & 0x1)))
	    {
	      switch (ether_type1)
		{
		case ETHERNET_TYPE_IP4:
		  ASSERT (em->l2_emulations[sw_if_index1].enabled);
		  ++ip4_hits;
		  next1 = L2_EMULATION_NEXT_IP4;
		  vlib_buffer_advance (b1, l2_len1);
		  break;
		case ETHERNET_TYPE_IP6:
		  ASSERT (em->l2_emulations[sw_if_index1].enabled);
		  ++ip6_hits;
		  next1 = L2_EMULATION_NEXT_IP6;
		  vlib_buffer_advance (b1, l2_len1);
		default:
		  break;
		}
	    }
	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      l2_emulation_trace_t *t =
		vlib_add_trace (vm, node, b0, sizeof (*t));
	      t->extracted = (next0 != ~0);
	    }
	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
			     && (b1->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      l2_emulation_trace_t *t =
		vlib_add_trace (vm, node, b1, sizeof (*t));
	      t->extracted = (next1 != ~0);
	    }

	  /* Determine the next node and remove ourself from bitmap */
	  if (PREDICT_TRUE (next0 == ~0))
	    next0 = vnet_l2_feature_next (b0, em->l2_input_feat_next,
					  L2INPUT_FEAT_L2_EMULATION);

	  /* Determine the next node and remove ourself from bitmap */
	  if (PREDICT_TRUE (next1 == ~0))
	    next1 = vnet_l2_feature_next (b1, em->l2_input_feat_next,
					  L2INPUT_FEAT_L2_EMULATION);

	  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)
	{
	  vlib_buffer_t *b0;
	  u32 sw_if_index0;
	  u16 ether_type0;
	  u32 next0 = ~0;
	  u8 l2_len0;
	  u32 bi0;
	  u8 *h0;

	  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);
	  l2_len0 = vnet_buffer (b0)->l2.l2_len;

	  h0 = vlib_buffer_get_current (b0);
	  ether_type0 = clib_net_to_host_u16 (*(u16 *) (h0 + l2_len0 - 2));
	  sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];

	  /*
	   * only extract unicast
	   */
	  if (PREDICT_TRUE (!(h0[0] & 0x1)))
	    {
	      switch (ether_type0)
		{
		case ETHERNET_TYPE_IP4:
		  ASSERT (em->l2_emulations[sw_if_index0].enabled);
		  ++ip4_hits;
		  next0 = L2_EMULATION_NEXT_IP4;
		  vlib_buffer_advance (b0, l2_len0);
		  break;
		case ETHERNET_TYPE_IP6:
		  ASSERT (em->l2_emulations[sw_if_index0].enabled);
		  ++ip6_hits;
		  next0 = L2_EMULATION_NEXT_IP6;
		  vlib_buffer_advance (b0, l2_len0);
		default:
		  break;
		}
	    }

	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      l2_emulation_trace_t *t =
		vlib_add_trace (vm, node, b0, sizeof (*t));
	      t->extracted = (next0 != ~0);
	    }

	  /* Determine the next node and remove ourself from bitmap */
	  if (PREDICT_TRUE (next0 == ~0))
	    next0 = vnet_l2_feature_next (b0, em->l2_input_feat_next,
					  L2INPUT_FEAT_L2_EMULATION);

	  /* 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, node->node_index,
			       L2_EMULATION_ERROR_IP4, ip4_hits);
  vlib_node_increment_counter (vm, node->node_index,
			       L2_EMULATION_ERROR_IP6, ip6_hits);

  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (l2_emulation_node) = {
  .name = "l2-emulation",
  .vector_size = sizeof (u32),
  .format_trace = format_l2_emulation_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,

  .n_errors = ARRAY_LEN(l2_emulation_error_strings),
  .error_strings = l2_emulation_error_strings,

  .n_next_nodes = L2_EMULATION_N_NEXT,

  /* edit / add dispositions here */
  .next_nodes = {
    [L2_EMULATION_NEXT_IP4] = "ip4-input",
    [L2_EMULATION_NEXT_IP6] = "ip6-input",
  },
};
/* *INDENT-ON* */

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