/*
 * 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.
 */
/*
  Copyright (c) 2005 Eliot Dresselhaus

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following con
/*
 * Copyright (c) 2016 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 L2 LISP-GPE decap code.
 *
 */
#include <vlib/vlib.h>
#include <vnet/pg/pg.h>
#include <vnet/lisp-gpe/lisp_gpe.h>

typedef struct
{
  u32 next_index;
  u32 tunnel_index;
  u32 error;
  lisp_gpe_header_t h;
} lisp_gpe_rx_trace_t;

static u8 *
format_lisp_gpe_rx_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 *);
  lisp_gpe_rx_trace_t *t = va_arg (*args, lisp_gpe_rx_trace_t *);

  if (t->tunnel_index != ~0)
    {
      s = format (s, "LISP-GPE: tunnel %d next %d error %d", t->tunnel_index,
		  t->next_index, t->error);
    }
  else
    {
      s = format (s, "LISP-GPE: no tunnel next %d error %d\n", t->next_index,
		  t->error);
    }
  s = format (s, "\n  %U", format_lisp_gpe_header_with_length, &t->h,
	      (u32) sizeof (t->h) /* max size */ );
  return s;
}

static u32 next_proto_to_next_index[LISP_GPE_NEXT_PROTOS] = {
  LISP_GPE_INPUT_NEXT_DROP,
  LISP_GPE_INPUT_NEXT_IP4_INPUT,
  LISP_GPE_INPUT_NEXT_IP6_INPUT,
  LISP_GPE_INPUT_NEXT_L2_INPUT,
  LISP_GPE_INPUT_NEXT_DROP
};

always_inline u32
next_protocol_to_next_index (lisp_gpe_header_t * lgh, u8 * next_header)
{
  lisp_gpe_main_t *lgm = vnet_lisp_gpe_get_main ();

  /* lisp-gpe router */
  if (PREDICT_TRUE ((lgh->flags & LISP_GPE_FLAGS_P)
		    || GPE_ENCAP_VXLAN == lgm->encap_mode))
    {
      if (PREDICT_FALSE (lgh->next_protocol >= LISP_GPE_NEXT_PROTOS))
	return LISP_GPE_INPUT_NEXT_DROP;

      return next_proto_to_next_index[lgh->next_protocol];
    }
  /* legacy lisp router */
  else if ((lgh->flags & LISP_GPE_FLAGS_P) == 0)
    {
      ip4_header_t *iph = (ip4_header_t *) next_header;
      if ((iph->ip_version_and_header_length & 0xF0) == 0x40)
	return LISP_GPE_INPUT_NEXT_IP4_INPUT;
      else if ((iph->ip_version_and_header_length & 0xF0) == 0x60)
	return LISP_GPE_INPUT_NEXT_IP6_INPUT;
      else
	return LISP_GPE_INPUT_NEXT_DROP;
    }
  else
    return LISP_GPE_INPUT_NEXT_DROP;
}

always_inline tunnel_lookup_t *
next_index_to_iface (lisp_gpe_main_t * lgm, u32 next_index)
{
  if (LISP_GPE_INPUT_NEXT_IP4_INPUT == next_index
      || LISP_GPE_INPUT_NEXT_IP6_INPUT == next_index)
    return &lgm->l3_ifaces;
  else if (LISP_GPE_INPUT_NEXT_L2_INPUT == next_index)
    return &lgm->l2_ifaces;
  else if (LISP_GPE_INPUT_NEXT_NSH_INPUT == next_index)
    return &lgm->nsh_ifaces;
  clib_warning ("next_index not associated to an interface!");
  return 0;
}

static_always_inline void
incr_decap_stats (vnet_main_t * vnm, u32 thread_index, u32 length,
		  u32 sw_if_index, u32 * last_sw_if_index, u32 * n_packets,
		  u32 * n_bytes)
{
  vnet_interface_main_t *im;

  if (PREDICT_TRUE (sw_if_index == *last_sw_if_index))
    {
      *n_packets += 1;
      *n_bytes += length;
    }
  else
    {
      if (PREDICT_TRUE (*last_sw_if_index != ~0))
	{
	  im = &vnm->interface_main;

	  vlib_increment_combined_counter (im->combined_sw_if_counters +
					   VNET_INTERFACE_COUNTER_RX,
					   thread_index, *last_sw_if_index,
					   *n_packets, *n_bytes);
	}
      *last_sw_if_index = sw_if_index;
      *n_packets = 1;
      *n_bytes = length;
    }
}

/**
 * @brief LISP-GPE decap dispatcher.
 * @node lisp_gpe_input_inline
 *
 * LISP-GPE decap dispatcher.
 *
 * Decaps IP-UDP-LISP-GPE header and based on the next protocol and in the
 * GPE header and the vni decides the next node to forward the packet to.
 *
 * @param[in]   vm      vlib_main_t corresponding to current thread.
 * @param[in]   node    vlib_node_runtime_t data for this node.
 * @param[in]   frame   vlib_frame_t whose contents should be dispatched.
 *
 * @return number of vectors in frame.
 */
static uword
lisp_gpe_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
		       vlib_frame_t * from_frame, u8 is_v4)
{
  u32 n_left_from, next_index, *from, *to_next, thread_index;
  u32 n_bytes = 0, n_packets = 0, last_sw_if_index = ~0, drops = 0;
  lisp_gpe_main_t *lgm = vnet_lisp_gpe_get_main ();

  thread_index = vm->thread_index;
  from = vlib_frame_vector_args (from_frame);
  n_left_from = 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 bi0, bi1;
	  vlib_buffer_t *b0, *b1;
	  ip4_udp_lisp_gpe_header_t *iul4_0, *iul4_1;
	  ip6_udp_lisp_gpe_header_t *iul6_0, *iul6_1;
	  lisp_gpe_header_t *lh0, *lh1;
	  u32 next0, next1, error0, error1;
	  uword *si0, *si1;
	  tunnel_lookup_t *tl0, *tl1;

	  /* 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);

	  /* udp leaves current_data pointing at the lisp header */
	  if (is_v4)
	    {
	      vlib_buffer_advance (b0,
				   -(word) (sizeof (udp_header_t) +
					    sizeof (ip4_header_t)));
	      vlib_buffer_advance (b1,
				   -(word) (sizeof (udp_header_t) +
					    sizeof (ip4_header_t)));

	      iul4_0 = vlib_buffer_get_current (b0);
	      iul4_1 = vlib_buffer_get_current (b1);

	      /* pop (ip, udp, lisp-gpe) */
	      vlib_buffer_advance (b0, sizeof (*iul4_0));
	      vlib_buffer_advance (b1, sizeof (*iul4_1));

	      lh0 = &iul4_0->lisp;
	      lh1 = &iul4_1->lisp;
	    }
	  else
	    {
	      vlib_buffer_advance (b0,
				   -(word) (sizeof (udp_header_t) +
					    sizeof (ip6_header_t)));
	      vlib_buffer_advance (b1,
				   -(word) (sizeof (udp_header_t) +
					    sizeof (ip6_header_t)));

	      iul6_0 = vlib_buffer_get_current (b0);
	      iul6_1 = vlib_buffer_get_current (b1);

	      /* pop (ip, udp, lisp-gpe) */
	      vlib_buffer_advance (b0, sizeof (*iul6_0));
	      vlib_buffer_advance (b1, sizeof (*iul6_1));

	      lh0 = &iul6_0->lisp;
	      lh1 = &iul6_1->lisp;
	    }

	  /* determine next_index from lisp-gpe header */
	  next0 = next_protocol_to_next_index (lh0,
					       vlib_buffer_get_current (b0));
	  next1 = next_protocol_to_next_index (lh1,
					       vlib_buffer_get_current (b1));

	  /* determine if tunnel is l2 or l3 */
	  tl0 = next_index_to_iface (lgm, next0);
	  tl1 = next_index_to_iface (lgm, next1);

	  /* map iid/vni to lisp-gpe sw_if_index which is used by ipx_input to
	   * decide the rx vrf and the input features to be applied */
	  si0 = hash_get (tl0->sw_if_index_by_vni,
			  clib_net_to_host_u32 (lh0->iid << 8));
	  si1 = hash_get (tl1->sw_if_index_by_vni,
			  clib_net_to_host_u32 (lh1->iid << 8));


	  /* Required to make the l2 tag push / pop code work on l2 subifs */
	  vnet_update_l2_len (b0);
	  vnet_update_l2_len (b1);

	  if (si0)
	    {
	      incr_decap_stats (lgm->vnet_main, thread_index,
				vlib_buffer_length_in_chain (vm, b0), si0[0],
				&last_sw_if_index, &n_packets, &n_bytes);
	      vnet_buffer (b0)->sw_if_index[VLIB_RX] = si0[0];
	      error0 = 0;
	    }
	  else
	    {
	      next0 = LISP_GPE_INPUT_NEXT_DROP;
	      error0 = LISP_GPE_ERROR_NO_TUNNEL;
	      drops++;
	    }

	  if (si1)
	    {
	      incr_decap_stats (lgm->vnet_main, thread_index,
				vlib_buffer_length_in_chain (vm, b1), si1[0],
				&last_sw_if_index, &n_packets, &n_bytes);
	      vnet_buffer (b1)->sw_if_index[VLIB_RX] = si1[0];
	      error1 = 0;
	    }
	  else
	    {
	      next1 = LISP_GPE_INPUT_NEXT_DROP;
	      error1 = LISP_GPE_ERROR_NO_TUNNEL;
	      drops++;
	    }

	  b0->error = error0 ? node->errors[error0] : 0;
	  b1->error = error1 ? node->errors[error1] : 0;

	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      lisp_gpe_rx_trace_t *tr = vlib_add_trace (vm, node, b0,
							sizeof (*tr));
	      tr->next_index = next0;
	      tr->error = error0;
	      tr->h = lh0[0];
	    }

	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      lisp_gpe_rx_trace_t *tr = vlib_add_trace (vm, node, b1,
							sizeof (*tr));
	      tr->next_index = next1;
	      tr->error = error1;
	      tr->h = lh1[0];
	    }

	  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;
	  ip4_udp_lisp_gpe_header_t *iul4_0;
	  ip6_udp_lisp_gpe_header_t *iul6_0;
	  lisp_gpe_header_t *lh0;
	  u32 error0;
	  uword *si0;
	  tunnel_lookup_t *tl0;

	  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);

	  /* udp leaves current_data pointing at the lisp header
	   * TODO: there's no difference in processing between v4 and v6
	   * encapsulated packets so the code should be simplified if ip header
	   * info is not going to be used for dp smrs/dpsec */
	  if (is_v4)
	    {
	      vlib_buffer_advance (b0,
				   -(word) (sizeof (udp_header_t) +
					    sizeof (ip4_header_t)));

	      iul4_0 = vlib_buffer_get_current (b0);

	      /* pop (ip, udp, lisp-gpe) */
	      vlib_buffer_advance (b0, sizeof (*iul4_0));

	      lh0 = &iul4_0->lisp;
	    }
	  else
	    {
	      vlib_buffer_advance (b0,
				   -(word) (sizeof (udp_header_t) +
					    sizeof (ip6_header_t)));

	      iul6_0 = vlib_buffer_get_current (b0);

	      /* pop (ip, udp, lisp-gpe) */
	      vlib_buffer_advance (b0, sizeof (*iul6_0));

	      lh0 = &iul6_0->lisp;
	    }

	  /* TODO if security is to be implemented, something similar to RPF,
	   * probably we'd like to check that the peer is allowed to send us
	   * packets. For this, we should use the tunnel table OR check that
	   * we have a mapping for the source eid and that the outer source of
	   * the packet is one of its locators */

	  /* determine next_index from lisp-gpe header */
	  next0 = next_protocol_to_next_index (lh0,
					       vlib_buffer_get_current (b0));

	  /* determine if tunnel is l2 or l3 */
	  tl0 = next_index_to_iface (lgm, next0);

	  /* map iid/vni to lisp-gpe sw_if_index which is used by ipx_input to
	   * decide the rx vrf and the input features to be applied.
	   * NOTE: vni uses only the first 24 bits */
	  si0 = hash_get (tl0->sw_if_index_by_vni,
			  clib_net_to_host_u32 (lh0->iid << 8));

	  /* Required to make the l2 tag push / pop code work on l2 subifs */
	  vnet_update_l2_len (b0);

	  if (si0)
	    {
	      incr_decap_stats (lgm->vnet_main, thread_index,
				vlib_buffer_length_in_chain (vm, b0), si0[0],
				&last_sw_if_index, &n_packets, &n_bytes);
	      vnet_buffer (b0)->sw_if_index[VLIB_RX] = si0[0];
	      error0 = 0;
	    }
	  else
	    {
	      next0 = LISP_GPE_INPUT_NEXT_DROP;
	      error0 = LISP_GPE_ERROR_NO_TUNNEL;
	      drops++;
	    }

	  /* TODO error handling if security is implemented */
	  b0->error = error0 ? node->errors[error0] : 0;

	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      lisp_gpe_rx_trace_t *tr = vlib_add_trace (vm, node, b0,
							sizeof (*tr));
	      tr->next_index = next0;
	      tr->error = error0;
	      tr->h = lh0[0];
	    }

	  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);
    }

  /* flush iface stats */
  incr_decap_stats (lgm->vnet_main, thread_index, 0, ~0, &last_sw_if_index,
		    &n_packets, &n_bytes);
  vlib_node_increment_counter (vm, lisp_gpe_ip4_input_node.index,
			       LISP_GPE_ERROR_NO_TUNNEL, drops);
  return from_frame->n_vectors;
}

static uword
lisp_gpe_ip4_input (vlib_main_t * vm, vlib_node_runtime_t * node,
		    vlib_frame_t * from_frame)
{
  return lisp_gpe_input_inline (vm, node, from_frame, 1);
}

static uword
lisp_gpe_ip6_input (vlib_main_t * vm, vlib_node_runtime_t * node,
		    vlib_frame_t * from_frame)
{
  return lisp_gpe_input_inline (vm, node, from_frame, 0);
}

static char *lisp_gpe_ip4_input_error_strings[] = {
#define lisp_gpe_error(n,s) s,
#include <vnet/lisp-gpe/lisp_gpe_error.def>
#undef lisp_gpe_error
};

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (lisp_gpe_ip4_input_node) = {
  .function = lisp_gpe_ip4_input,
  .name = "lisp-gpe-ip4-input",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_next_nodes = LISP_GPE_INPUT_N_NEXT,
  .next_nodes = {
#define _(s,n) [LISP_GPE_INPUT_NEXT_##s] = n,
    foreach_lisp_gpe_ip_input_next
#undef _
  },

  .n_errors = ARRAY_LEN (lisp_gpe_ip4_input_error_strings),
  .error_strings = lisp_gpe_ip4_input_error_strings,

  .format_buffer = format_lisp_gpe_header_with_length,
  .format_trace = format_lisp_gpe_rx_trace,
  // $$$$ .unformat_buffer = unformat_lisp_gpe_header,
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (lisp_gpe_ip6_input_node) = {
  .function = lisp_gpe_ip6_input,
  .name = "lisp-gpe-ip6-input",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_next_nodes = LISP_GPE_INPUT_N_NEXT,
  .next_nodes = {
#define _(s,n) [LISP_GPE_INPUT_NEXT_##s] = n,
    foreach_lisp_gpe_ip_input_next
#undef _
  },

  .n_errors = ARRAY_LEN (lisp_gpe_ip4_input_error_strings),
  .error_strings = lisp_gpe_ip4_input_error_strings,

  .format_buffer = format_lisp_gpe_header_with_length,
  .format_trace = format_lisp_gpe_rx_trace,
  // $$$$ .unformat_buffer = unformat_lisp_gpe_header,
};
/* *INDENT-ON* */

/**
 * Adds arc from lisp-gpe-input to nsh-input if nsh-input is available
 */
static void
gpe_add_arc_from_input_to_nsh ()
{
  lisp_gpe_main_t *lgm = vnet_lisp_gpe_get_main ();
  vlib_main_t *vm = lgm->vlib_main;
  vlib_node_t *nsh_input;

  /* Arc already exists */
  if (next_proto_to_next_index[LISP_GPE_NEXT_PROTO_NSH]
      != LISP_GPE_INPUT_NEXT_DROP)
    return;

  /* Check if nsh-input is available */
  if ((nsh_input = vlib_get_node_by_name (vm, (u8 *) "nsh-input")))
    {
      u32 slot4, slot6;
      slot4 = vlib_node_add_next_with_slot (vm, lisp_gpe_ip4_input_node.index,
					    nsh_input->index,
					    LISP_GPE_NEXT_PROTO_NSH);
      slot6 = vlib_node_add_next_with_slot (vm, lisp_gpe_ip6_input_node.index,
					    nsh_input->index,
					    LISP_GPE_NEXT_PROTO_NSH);
      ASSERT (slot4 == slot6 && slot4 == LISP_GPE_INPUT_NEXT_NSH_INPUT);

      next_proto_to_next_index[LISP_GPE_NEXT_PROTO_NSH] = slot4;
    }
}

/** GPE decap init function. */
clib_error_t *
gpe_decap_init (vlib_main_t * vm)
{
  clib_error_t *error = 0;

  if ((error = vlib_call_init_function (vm, lisp_gpe_init)))
    return error;

  gpe_add_arc_from_input_to_nsh ();
  return 0;
}

static uword
lisp_gpe_nsh_dummy_input (vlib_main_t * vm, vlib_node_runtime_t * node,
			  vlib_frame_t * from_frame)
{
  vlib_node_increment_counter (vm, node->node_index, 0, 1);
  return from_frame->n_vectors;
}

static char *lisp_gpe_nsh_dummy_error_strings[] = {
  "lisp gpe dummy nsh decap",
};

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (lisp_gpe_nsh_dummy_input_node) = {
  .function = lisp_gpe_nsh_dummy_input,
  .name = "lisp-gpe-nsh-dummy-input",
  .vector_size = sizeof (u32),
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_next_nodes = 1,

  .n_errors = 1,
  .error_strings = lisp_gpe_nsh_dummy_error_strings,

  .next_nodes = {
      [0] = "error-drop",
  },
};
/* *INDENT-ON* */

static clib_error_t *
lisp_add_dummy_nsh_node_command_fn (vlib_main_t * vm,
				    unformat_input_t * input,
				    vlib_cli_command_t * cmd)
{
  lisp_gpe_main_t *lgm = vnet_lisp_gpe_get_main ();
  vlib_node_add_next (lgm->vlib_main, lisp_gpe_ip4_input_node.index,
		      lisp_gpe_nsh_dummy_input_node.index);
  next_proto_to_next_index[LISP_GPE_NEXT_PROTO_NSH] =
    LISP_GPE_INPUT_NEXT_NSH_INPUT;
  return 0;
}

/* *INDENT-OFF* */
VLIB_CLI_COMMAND (lisp_add_dummy_nsh_node_command, static) = {
  .path = "test one nsh add-dummy-decap-node",
  .function = lisp_add_dummy_nsh_node_command_fn,
};
/* *INDENT-ON* */

VLIB_INIT_FUNCTION (gpe_decap_init);

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