/*
 * Copyright (c) 2018 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 <vnet/dpo/dvr_dpo.h>
#include <vnet/dpo/drop_dpo.h>
#include <vnet/vxlan-gbp/vxlan_gbp_packet.h>
#include <vnet/vxlan-gbp/vxlan_gbp.h>

#include <plugins/gbp/gbp.h>
#include <plugins/gbp/gbp_policy.h>
#include <plugins/gbp/gbp_policy_dpo.h>
#include <plugins/gbp/gbp_recirc.h>
#include <plugins/gbp/gbp_contract.h>

#ifndef CLIB_MARCH_VARIANT
/**
 * DPO pool
 */
gbp_policy_dpo_t *gbp_policy_dpo_pool;

/**
 * DPO type registered for these GBP FWD
 */
dpo_type_t gbp_policy_dpo_type;

static gbp_policy_dpo_t *
gbp_policy_dpo_alloc (void)
{
  gbp_policy_dpo_t *gpd;

  pool_get_aligned_zero (gbp_policy_dpo_pool, gpd, CLIB_CACHE_LINE_BYTES);

  return (gpd);
}

static inline gbp_policy_dpo_t *
gbp_policy_dpo_get_from_dpo (const dpo_id_t * dpo)
{
  ASSERT (gbp_policy_dpo_type == dpo->dpoi_type);

  return (gbp_policy_dpo_get (dpo->dpoi_index));
}

static inline index_t
gbp_policy_dpo_get_index (gbp_policy_dpo_t * gpd)
{
  return (gpd - gbp_policy_dpo_pool);
}

static void
gbp_policy_dpo_lock (dpo_id_t * dpo)
{
  gbp_policy_dpo_t *gpd;

  gpd = gbp_policy_dpo_get_from_dpo (dpo);
  gpd->gpd_locks++;
}

static void
gbp_policy_dpo_unlock (dpo_id_t * dpo)
{
  gbp_policy_dpo_t *gpd;

  gpd = gbp_policy_dpo_get_from_dpo (dpo);
  gpd->gpd_locks--;

  if (0 == gpd->gpd_locks)
    {
      dpo_reset (&gpd->gpd_dpo);
      pool_put (gbp_policy_dpo_pool, gpd);
    }
}

static u32
gbp_policy_dpo_get_urpf (const dpo_id_t * dpo)
{
  gbp_policy_dpo_t *gpd;

  gpd = gbp_policy_dpo_get_from_dpo (dpo);

  return (gpd->gpd_sw_if_index);
}

void
gbp_policy_dpo_add_or_lock (dpo_proto_t dproto,
			    gbp_scope_t scope,
			    sclass_t sclass, u32 sw_if_index, dpo_id_t * dpo)
{
  gbp_policy_dpo_t *gpd;
  dpo_id_t parent = DPO_INVALID;

  gpd = gbp_policy_dpo_alloc ();

  gpd->gpd_proto = dproto;
  gpd->gpd_sw_if_index = sw_if_index;
  gpd->gpd_sclass = sclass;
  gpd->gpd_scope = scope;

  if (~0 != sw_if_index)
    {
      /*
       * stack on the DVR DPO for the output interface
       */
      dvr_dpo_add_or_lock (sw_if_index, dproto, &parent);
    }
  else
    {
      dpo_copy (&parent, drop_dpo_get (dproto));
    }

  dpo_stack (gbp_policy_dpo_type, dproto, &gpd->gpd_dpo, &parent);
  dpo_set (dpo, gbp_policy_dpo_type, dproto, gbp_policy_dpo_get_index (gpd));
}

u8 *
format_gbp_policy_dpo (u8 * s, va_list * ap)
{
  index_t index = va_arg (*ap, index_t);
  u32 indent = va_arg (*ap, u32);
  gbp_policy_dpo_t *gpd = gbp_policy_dpo_get (index);
  vnet_main_t *vnm = vnet_get_main ();

  s = format (s, "gbp-policy-dpo: %U, scope:%d sclass:%d out:%U",
	      format_dpo_proto, gpd->gpd_proto,
	      gpd->gpd_scope, (int) gpd->gpd_sclass,
	      format_vnet_sw_if_index_name, vnm, gpd->gpd_sw_if_index);
  s = format (s, "\n%U", format_white_space, indent + 2);
  s = format (s, "%U", format_dpo_id, &gpd->gpd_dpo, indent + 4);

  return (s);
}

/**
 * Interpose a policy DPO
 */
static void
gbp_policy_dpo_interpose (const dpo_id_t * original,
			  const dpo_id_t * parent, dpo_id_t * clone)
{
  gbp_policy_dpo_t *gpd, *gpd_clone;

  gpd_clone = gbp_policy_dpo_alloc ();
  gpd = gbp_policy_dpo_get (original->dpoi_index);

  gpd_clone->gpd_proto = gpd->gpd_proto;
  gpd_clone->gpd_scope = gpd->gpd_scope;
  gpd_clone->gpd_sclass = gpd->gpd_sclass;
  gpd_clone->gpd_sw_if_index = gpd->gpd_sw_if_index;

  /*
   * if no interface is provided, grab one from the parent
   * on which we stack
   */
  if (~0 == gpd_clone->gpd_sw_if_index)
    gpd_clone->gpd_sw_if_index = dpo_get_urpf (parent);

  dpo_stack (gbp_policy_dpo_type,
	     gpd_clone->gpd_proto, &gpd_clone->gpd_dpo, parent);

  dpo_set (clone,
	   gbp_policy_dpo_type,
	   gpd_clone->gpd_proto, gbp_policy_dpo_get_index (gpd_clone));
}

const static dpo_vft_t gbp_policy_dpo_vft = {
  .dv_lock = gbp_policy_dpo_lock,
  .dv_unlock = gbp_policy_dpo_unlock,
  .dv_format = format_gbp_policy_dpo,
  .dv_get_urpf = gbp_policy_dpo_get_urpf,
  .dv_mk_interpose = gbp_policy_dpo_interpose,
};

/**
 * @brief The per-protocol VLIB graph nodes that are assigned to a glean
 *        object.
 *
 * this means that these graph nodes are ones from which a glean is the
 * parent object in the DPO-graph.
 */
const static char *const gbp_policy_dpo_ip4_nodes[] = {
  "ip4-gbp-policy-dpo",
  NULL,
};

const static char *const gbp_policy_dpo_ip6_nodes[] = {
  "ip6-gbp-policy-dpo",
  NULL,
};

const static char *const *const gbp_policy_dpo_nodes[DPO_PROTO_NUM] = {
  [DPO_PROTO_IP4] = gbp_policy_dpo_ip4_nodes,
  [DPO_PROTO_IP6] = gbp_policy_dpo_ip6_nodes,
};

dpo_type_t
gbp_policy_dpo_get_type (void)
{
  return (gbp_policy_dpo_type);
}

static clib_error_t *
gbp_policy_dpo_module_init (vlib_main_t * vm)
{
  gbp_policy_dpo_type = dpo_register_new_type (&gbp_policy_dpo_vft,
					       gbp_policy_dpo_nodes);

  return (NULL);
}

VLIB_INIT_FUNCTION (gbp_policy_dpo_module_init);
#endif /* CLIB_MARCH_VARIANT */

typedef enum
{
  GBP_POLICY_DROP,
  GBP_POLICY_N_NEXT,
} gbp_policy_next_t;

always_inline u32
gbp_rule_l3_redirect (const gbp_rule_t * gu, vlib_buffer_t * b0, int is_ip6)
{
  gbp_policy_node_t pnode;
  const dpo_id_t *dpo;
  dpo_proto_t dproto;

  pnode = (is_ip6 ? GBP_POLICY_NODE_IP6 : GBP_POLICY_NODE_IP4);
  dproto = (is_ip6 ? DPO_PROTO_IP6 : DPO_PROTO_IP4);
  dpo = &gu->gu_dpo[pnode][dproto];

  /* The flow hash is still valid as this is a IP packet being switched */
  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpo->dpoi_index;

  return (dpo->dpoi_next_node);
}

always_inline uword
gbp_policy_dpo_inline (vlib_main_t * vm,
		       vlib_node_runtime_t * node,
		       vlib_frame_t * from_frame, u8 is_ip6)
{
  gbp_main_t *gm = &gbp_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 n_allow_intra, n_allow_a_bit, n_allow_sclass_1;

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;
  n_allow_intra = n_allow_a_bit = n_allow_sclass_1 = 0;

  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 > 0 && n_left_to_next > 0)
	{
	  gbp_rule_action_t action0 = GBP_RULE_DENY;
	  u32 acl_match = ~0, rule_match = ~0;
	  const gbp_policy_dpo_t *gpd0;
	  gbp_contract_error_t err0;
	  gbp_contract_key_t key0;
	  vlib_buffer_t *b0;
	  gbp_rule_t *rule0;
	  u32 bi0, next0;

	  bi0 = from[0];
	  to_next[0] = bi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;
	  next0 = GBP_POLICY_DROP;

	  b0 = vlib_get_buffer (vm, bi0);

	  gpd0 = gbp_policy_dpo_get (vnet_buffer (b0)->ip.adj_index[VLIB_TX]);
	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = gpd0->gpd_dpo.dpoi_index;

	  /*
	   * Reflection check; in and out on an ivxlan tunnel
	   */
	  if ((~0 != vxlan_gbp_tunnel_by_sw_if_index (gpd0->gpd_sw_if_index))
	      && (vnet_buffer2 (b0)->gbp.flags & VXLAN_GBP_GPFLAGS_R))
	    {
	      goto trace;
	    }

	  if (vnet_buffer2 (b0)->gbp.flags & VXLAN_GBP_GPFLAGS_A)
	    {
	      next0 = gpd0->gpd_dpo.dpoi_next_node;
	      key0.as_u64 = ~0;
	      n_allow_a_bit++;
	      goto trace;
	    }

	  /* zero out the key to ensure the pad space is clear */
	  key0.as_u64 = 0;
	  key0.gck_src = vnet_buffer2 (b0)->gbp.sclass;

	  if (SCLASS_INVALID == key0.gck_src)
	    {
	      /*
	       * the src EPG is not set when the packet arrives on an EPG
	       * uplink interface and we do not need to apply policy
	       */
	      next0 = gpd0->gpd_dpo.dpoi_next_node;
	      goto trace;
	    }

	  key0.gck_scope = gpd0->gpd_scope;
	  key0.gck_dst = gpd0->gpd_sclass;

	  action0 =
	    gbp_contract_apply (vm, gm, &key0, b0, &rule0, &n_allow_intra,
				&n_allow_sclass_1, &acl_match, &rule_match,
				&err0,
				is_ip6 ? GBP_CONTRACT_APPLY_IP6 :
				GBP_CONTRACT_APPLY_IP4);
	  switch (action0)
	    {
	    case GBP_RULE_PERMIT:
	      next0 = gpd0->gpd_dpo.dpoi_next_node;
	      vnet_buffer2 (b0)->gbp.flags |= VXLAN_GBP_GPFLAGS_A;
	      break;
	    case GBP_RULE_REDIRECT:
	      next0 = gbp_rule_l3_redirect (rule0, b0, is_ip6);
	      vnet_buffer2 (b0)->gbp.flags |= VXLAN_GBP_GPFLAGS_A;
	      break;
	    case GBP_RULE_DENY:
	      next0 = GBP_POLICY_DROP;
	      b0->error = node->errors[err0];
	      break;
	    }

	trace:
	  gbp_policy_trace (vm, node, b0, &key0, action0, acl_match,
			    rule_match);

	  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,
			       GBP_CONTRACT_ERROR_ALLOW_INTRA, n_allow_intra);
  vlib_node_increment_counter (vm, node->node_index,
			       GBP_CONTRACT_ERROR_ALLOW_A_BIT, n_allow_a_bit);
  vlib_node_increment_counter (vm, node->node_index,
			       GBP_CONTRACT_ERROR_ALLOW_SCLASS_1,
			       n_allow_sclass_1);
  return from_frame->n_vectors;
}

VLIB_NODE_FN (ip4_gbp_policy_dpo_node) (vlib_main_t * vm,
					vlib_node_runtime_t * node,
					vlib_frame_t * from_frame)
{
  return (gbp_policy_dpo_inline (vm, node, from_frame, 0));
}

VLIB_NODE_FN (ip6_gbp_policy_dpo_node) (vlib_main_t * vm,
					vlib_node_runtime_t * node,
					vlib_frame_t * from_frame)
{
  return (gbp_policy_dpo_inline (vm, node, from_frame, 1));
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (ip4_gbp_policy_dpo_node) = {
    .name = "ip4-gbp-policy-dpo",
    .vector_size = sizeof (u32),
    .format_trace = format_gbp_policy_trace,

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

    .n_next_nodes = GBP_POLICY_N_NEXT,
    .next_nodes =
    {
        [GBP_POLICY_DROP] = "ip4-drop",
    }
};
VLIB_REGISTER_NODE (ip6_gbp_policy_dpo_node) = {
    .name = "ip6-gbp-policy-dpo",
    .vector_size = sizeof (u32),
    .format_trace = format_gbp_policy_trace,

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

    .n_next_nodes = GBP_POLICY_N_NEXT,
    .next_nodes =
    {
        [GBP_POLICY_DROP] = "ip6-drop",
    }
};
/* *INDENT-ON* */

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