/*
 * Copyright (c) 2015-2019 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.
 */
/*
 * ip/ip4_forward.h: IP v4 forwarding
 *
 * Copyright (c) 2008 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 conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef __included_ip4_forward_h__
#define __included_ip4_forward_h__

#include <vppinfra/cache.h>
#include <vnet/fib/ip4_fib.h>
#include <vnet/dpo/load_balance_map.h>
#include <vnet/ip/ip4_inlines.h>

/**
 * @file
 * @brief IPv4 Forwarding.
 *
 * This file contains the source code for IPv4 forwarding.
 */

always_inline uword
ip4_lookup_inline (vlib_main_t * vm,
		   vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  ip4_main_t *im = &ip4_main;
  vlib_combined_counter_main_t *cm = &load_balance_main.lbm_to_counters;
  u32 n_left, *from;
  u32 thread_index = vm->thread_index;
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE];
  vlib_buffer_t **b = bufs;
  u16 nexts[VLIB_FRAME_SIZE], *next;

  from = vlib_frame_vector_args (frame);
  n_left = frame->n_vectors;
  next = nexts;
  vlib_get_buffers (vm, from, bufs, n_left);

#if (CLIB_N_PREFETCHES >= 8)
  while (n_left >= 4)
    {
      ip4_header_t *ip0, *ip1, *ip2, *ip3;
      const load_balance_t *lb0, *lb1, *lb2, *lb3;
      ip4_address_t *dst_addr0, *dst_addr1, *dst_addr2, *dst_addr3;
      u32 lb_index0, lb_index1, lb_index2, lb_index3;
      flow_hash_config_t flow_hash_config0, flow_hash_config1;
      flow_hash_config_t flow_hash_config2, flow_hash_config3;
      u32 hash_c0, hash_c1, hash_c2, hash_c3;
      const dpo_id_t *dpo0, *dpo1, *dpo2, *dpo3;

      /* Prefetch next iteration. */
      if (n_left >= 8)
	{
	  vlib_prefetch_buffer_header (b[4], LOAD);
	  vlib_prefetch_buffer_header (b[5], LOAD);
	  vlib_prefetch_buffer_header (b[6], LOAD);
	  vlib_prefetch_buffer_header (b[7], LOAD);

	  CLIB_PREFETCH (b[4]->data, sizeof (ip0[0]), LOAD);
	  CLIB_PREFETCH (b[5]->data, sizeof (ip0[0]), LOAD);
	  CLIB_PREFETCH (b[6]->data, sizeof (ip0[0]), LOAD);
	  CLIB_PREFETCH (b[7]->data, sizeof (ip0[0]), LOAD);
	}

      ip0 = vlib_buffer_get_current (b[0]);
      ip1 = vlib_buffer_get_current (b[1]);
      ip2 = vlib_buffer_get_current (b[2]);
      ip3 = vlib_buffer_get_current (b[3]);

      dst_addr0 = &ip0->dst_address;
      dst_addr1 = &ip1->dst_address;
      dst_addr2 = &ip2->dst_address;
      dst_addr3 = &ip3->dst_address;

      ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, b[0]);
      ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, b[1]);
      ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, b[2]);
      ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, b[3]);

      ip4_fib_forwarding_lookup_x4 (
	vnet_buffer (b[0])->ip.fib_index, vnet_buffer (b[1])->ip.fib_index,
	vnet_buffer (b[2])->ip.fib_index, vnet_buffer (b[3])->ip.fib_index,
	dst_addr0, dst_addr1, dst_addr2, dst_addr3, &lb_index0, &lb_index1,
	&lb_index2, &lb_index3);

      ASSERT (lb_index0 && lb_index1 && lb_index2 && lb_index3);
      lb0 = load_balance_get (lb_index0);
      lb1 = load_balance_get (lb_index1);
      lb2 = load_balance_get (lb_index2);
      lb3 = load_balance_get (lb_index3);

      ASSERT (lb0->lb_n_buckets > 0);
      ASSERT (is_pow2 (lb0->lb_n_buckets));
      ASSERT (lb1->lb_n_buckets > 0);
      ASSERT (is_pow2 (lb1->lb_n_buckets));
      ASSERT (lb2->lb_n_buckets > 0);
      ASSERT (is_pow2 (lb2->lb_n_buckets));
      ASSERT (lb3->lb_n_buckets > 0);
      ASSERT (is_pow2 (lb3->lb_n_buckets));

      /* Use flow hash to compute multipath adjacency. */
      hash_c0 = vnet_buffer (b[0])->ip.flow_hash = 0;
      hash_c1 = vnet_buffer (b[1])->ip.flow_hash = 0;
      hash_c2 = vnet_buffer (b[2])->ip.flow_hash = 0;
      hash_c3 = vnet_buffer (b[3])->ip.flow_hash = 0;
      if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
	{
	  flow_hash_config0 = lb0->lb_hash_config;
	  hash_c0 = vnet_buffer (b[0])->ip.flow_hash =
	    ip4_compute_flow_hash (ip0, flow_hash_config0);
	  dpo0 =
	    load_balance_get_fwd_bucket (lb0,
					 (hash_c0 &
					  (lb0->lb_n_buckets_minus_1)));
	}
      else
	{
	  dpo0 = load_balance_get_bucket_i (lb0, 0);
	}
      if (PREDICT_FALSE (lb1->lb_n_buckets > 1))
	{
	  flow_hash_config1 = lb1->lb_hash_config;
	  hash_c1 = vnet_buffer (b[1])->ip.flow_hash =
	    ip4_compute_flow_hash (ip1, flow_hash_config1);
	  dpo1 =
	    load_balance_get_fwd_bucket (lb1,
					 (hash_c1 &
					  (lb1->lb_n_buckets_minus_1)));
	}
      else
	{
	  dpo1 = load_balance_get_bucket_i (lb1, 0);
	}
      if (PREDICT_FALSE (lb2->lb_n_buckets > 1))
	{
	  flow_hash_config2 = lb2->lb_hash_config;
	  hash_c2 = vnet_buffer (b[2])->ip.flow_hash =
	    ip4_compute_flow_hash (ip2, flow_hash_config2);
	  dpo2 =
	    load_balance_get_fwd_bucket (lb2,
					 (hash_c2 &
					  (lb2->lb_n_buckets_minus_1)));
	}
      else
	{
	  dpo2 = load_balance_get_bucket_i (lb2, 0);
	}
      if (PREDICT_FALSE (lb3->lb_n_buckets > 1))
	{
	  flow_hash_config3 = lb3->lb_hash_config;
	  hash_c3 = vnet_buffer (b[3])->ip.flow_hash =
	    ip4_compute_flow_hash (ip3, flow_hash_config3);
	  dpo3 =
	    load_balance_get_fwd_bucket (lb3,
					 (hash_c3 &
					  (lb3->lb_n_buckets_minus_1)));
	}
      else
	{
	  dpo3 = load_balance_get_bucket_i (lb3, 0);
	}

      next[0] = dpo0->dpoi_next_node;
      vnet_buffer (b[0])->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
      next[1] = dpo1->dpoi_next_node;
      vnet_buffer (b[1])->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;
      next[2] = dpo2->dpoi_next_node;
      vnet_buffer (b[2])->ip.adj_index[VLIB_TX] = dpo2->dpoi_index;
      next[3] = dpo3->dpoi_next_node;
      vnet_buffer (b[3])->ip.adj_index[VLIB_TX] = dpo3->dpoi_index;

      vlib_increment_combined_counter
	(cm, thread_index, lb_index0, 1,
	 vlib_buffer_length_in_chain (vm, b[0]));
      vlib_increment_combined_counter
	(cm, thread_index, lb_index1, 1,
	 vlib_buffer_length_in_chain (vm, b[1]));
      vlib_increment_combined_counter
	(cm, thread_index, lb_index2, 1,
	 vlib_buffer_length_in_chain (vm, b[2]));
      vlib_increment_combined_counter
	(cm, thread_index, lb_index3, 1,
	 vlib_buffer_length_in_chain (vm, b[3]));

      b += 4;
      next += 4;
      n_left -= 4;
    }
#elif (CLIB_N_PREFETCHES >= 4)
  while (n_left >= 4)
    {
      ip4_header_t *ip0, *ip1;
      const load_balance_t *lb0, *lb1;
      ip4_address_t *dst_addr0, *dst_addr1;
      u32 lb_index0, lb_index1;
      flow_hash_config_t flow_hash_config0, flow_hash_config1;
      u32 hash_c0, hash_c1;
      const dpo_id_t *dpo0, *dpo1;

      /* Prefetch next iteration. */
      {
	vlib_prefetch_buffer_header (b[2], LOAD);
	vlib_prefetch_buffer_header (b[3], LOAD);

	CLIB_PREFETCH (b[2]->data, sizeof (ip0[0]), LOAD);
	CLIB_PREFETCH (b[3]->data, sizeof (ip0[0]), LOAD);
      }

      ip0 = vlib_buffer_get_current (b[0]);
      ip1 = vlib_buffer_get_current (b[1]);

      dst_addr0 = &ip0->dst_address;
      dst_addr1 = &ip1->dst_address;

      ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, b[0]);
      ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, b[1]);

      ip4_fib_forwarding_lookup_x2 (
	vnet_buffer (b[0])->ip.fib_index, vnet_buffer (b[1])->ip.fib_index,
	dst_addr0, dst_addr1, &lb_index0, &lb_index1);

      ASSERT (lb_index0 && lb_index1);
      lb0 = load_balance_get (lb_index0);
      lb1 = load_balance_get (lb_index1);

      ASSERT (lb0->lb_n_buckets > 0);
      ASSERT (is_pow2 (lb0->lb_n_buckets));
      ASSERT (lb1->lb_n_buckets > 0);
      ASSERT (is_pow2 (lb1->lb_n_buckets));

      /* Use flow hash to compute multipath adjacency. */
      hash_c0 = vnet_buffer (b[0])->ip.flow_hash = 0;
      hash_c1 = vnet_buffer (b[1])->ip.flow_hash = 0;
      if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
	{
	  flow_hash_config0 = lb0->lb_hash_config;
	  hash_c0 = vnet_buffer (b[0])->ip.flow_hash =
	    ip4_compute_flow_hash (ip0, flow_hash_config0);
	  dpo0 =
	    load_balance_get_fwd_bucket (lb0,
					 (hash_c0 &
					  (lb0->lb_n_buckets_minus_1)));
	}
      else
	{
	  dpo0 = load_balance_get_bucket_i (lb0, 0);
	}
      if (PREDICT_FALSE (lb1->lb_n_buckets > 1))
	{
	  flow_hash_config1 = lb1->lb_hash_config;
	  hash_c1 = vnet_buffer (b[1])->ip.flow_hash =
	    ip4_compute_flow_hash (ip1, flow_hash_config1);
	  dpo1 =
	    load_balance_get_fwd_bucket (lb1,
					 (hash_c1 &
					  (lb1->lb_n_buckets_minus_1)));
	}
      else
	{
	  dpo1 = load_balance_get_bucket_i (lb1, 0);
	}

      next[0] = dpo0->dpoi_next_node;
      vnet_buffer (b[0])->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
      next[1] = dpo1->dpoi_next_node;
      vnet_buffer (b[1])->ip.adj_index[VLIB_TX] = dpo1->dpoi_index;

      vlib_increment_combined_counter
	(cm, thread_index, lb_index0, 1,
	 vlib_buffer_length_in_chain (vm, b[0]));
      vlib_increment_combined_counter
	(cm, thread_index, lb_index1, 1,
	 vlib_buffer_length_in_chain (vm, b[1]));

      b += 2;
      next += 2;
      n_left -= 2;
    }
#endif
  while (n_left > 0)
    {
      ip4_header_t *ip0;
      const load_balance_t *lb0;
      ip4_address_t *dst_addr0;
      u32 lbi0;
      flow_hash_config_t flow_hash_config0;
      const dpo_id_t *dpo0;
      u32 hash_c0;

      ip0 = vlib_buffer_get_current (b[0]);
      dst_addr0 = &ip0->dst_address;
      ip_lookup_set_buffer_fib_index (im->fib_index_by_sw_if_index, b[0]);

      lbi0 = ip4_fib_forwarding_lookup (vnet_buffer (b[0])->ip.fib_index,
					dst_addr0);

      ASSERT (lbi0);
      lb0 = load_balance_get (lbi0);

      ASSERT (lb0->lb_n_buckets > 0);
      ASSERT (is_pow2 (lb0->lb_n_buckets));

      /* Use flow hash to compute multipath adjacency. */
      hash_c0 = vnet_buffer (b[0])->ip.flow_hash = 0;
      if (PREDICT_FALSE (lb0->lb_n_buckets > 1))
	{
	  flow_hash_config0 = lb0->lb_hash_config;

	  hash_c0 = vnet_buffer (b[0])->ip.flow_hash =
	    ip4_compute_flow_hash (ip0, flow_hash_config0);
	  dpo0 =
	    load_balance_get_fwd_bucket (lb0,
					 (hash_c0 &
					  (lb0->lb_n_buckets_minus_1)));
	}
      else
	{
	  dpo0 = load_balance_get_bucket_i (lb0, 0);
	}

      next[0] = dpo0->dpoi_next_node;
      vnet_buffer (b[0])->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;

      vlib_increment_combined_counter (cm, thread_index, lbi0, 1,
				       vlib_buffer_length_in_chain (vm,
								    b[0]));

      b += 1;
      next += 1;
      n_left -= 1;
    }

  vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    ip4_forward_next_trace (vm, node, frame, VLIB_TX);

  return frame->n_vectors;
}

#endif /* __included_ip4_forward_h__ */

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