/*
 * replication.c : packet replication
 *
 * Copyright (c) 2013 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 <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vppinfra/error.h>
#include <vnet/ip/ip4_packet.h>
#include <vnet/replication.h>


replication_main_t replication_main;


replication_context_t *
replication_prep (vlib_main_t * vm,
		  vlib_buffer_t * b0, u32 recycle_node_index, u32 l2_packet)
{
  replication_main_t *rm = &replication_main;
  replication_context_t *ctx;
  uword thread_index = vm->thread_index;
  ip4_header_t *ip;
  u32 ctx_id;

  /* Allocate a context, reserve context 0 */
  if (PREDICT_FALSE (rm->contexts[thread_index] == 0))
    pool_get_aligned (rm->contexts[thread_index], ctx, CLIB_CACHE_LINE_BYTES);

  pool_get_aligned (rm->contexts[thread_index], ctx, CLIB_CACHE_LINE_BYTES);
  ctx_id = ctx - rm->contexts[thread_index];

  /* Save state from vlib buffer */
  ctx->saved_free_list_index = vlib_buffer_get_free_list_index (b0);
  ctx->current_data = b0->current_data;

  /* Set up vlib buffer hooks */
  b0->recycle_count = ctx_id;
  vlib_buffer_set_free_list_index (b0, rm->recycle_list_index);
  b0->flags |= VLIB_BUFFER_RECYCLE;

  /* Save feature state */
  ctx->recycle_node_index = recycle_node_index;

  /* Save vnet state */
  clib_memcpy (ctx->vnet_buffer, vnet_buffer (b0),
	       sizeof (vnet_buffer_opaque_t));

  /* Save packet contents */
  ctx->l2_packet = l2_packet;
  ip = (ip4_header_t *) vlib_buffer_get_current (b0);
  if (l2_packet)
    {
      /* Save ethernet header */
      ctx->l2_header[0] = ((u64 *) ip)[0];
      ctx->l2_header[1] = ((u64 *) ip)[1];
      ctx->l2_header[2] = ((u64 *) ip)[2];
      /* set ip to the true ip header */
      ip = (ip4_header_t *) (((u8 *) ip) + vnet_buffer (b0)->l2.l2_len);
    }

  /*
   * Copy L3 fields.
   * We need to save TOS for ip4 and ip6 packets.
   * Fortunately the TOS field is
   * in the first two bytes of both the ip4 and ip6 headers.
   */
  ctx->ip_tos = *((u16 *) (ip));

  /*
   * Save the ip4 checksum as well. We just blindly save the corresponding two
   * bytes even for ip6 packets.
   */
  ctx->ip4_checksum = ip->checksum;

  return ctx;
}


replication_context_t *
replication_recycle (vlib_main_t * vm, vlib_buffer_t * b0, u32 is_last)
{
  replication_main_t *rm = &replication_main;
  replication_context_t *ctx;
  uword thread_index = vm->thread_index;
  ip4_header_t *ip;

  /* Get access to the replication context */
  ctx = pool_elt_at_index (rm->contexts[thread_index], b0->recycle_count);

  /* Restore vnet buffer state */
  clib_memcpy (vnet_buffer (b0), ctx->vnet_buffer,
	       sizeof (vnet_buffer_opaque_t));

  /* Restore the packet start (current_data) and length */
  vlib_buffer_advance (b0, ctx->current_data - b0->current_data);

  /* Restore packet contents */
  ip = (ip4_header_t *) vlib_buffer_get_current (b0);
  if (ctx->l2_packet)
    {
      /* Restore ethernet header */
      ((u64 *) ip)[0] = ctx->l2_header[0];
      ((u64 *) ip)[1] = ctx->l2_header[1];
      ((u64 *) ip)[2] = ctx->l2_header[2];
      /* set ip to the true ip header */
      ip = (ip4_header_t *) (((u8 *) ip) + vnet_buffer (b0)->l2.l2_len);
    }

  // Restore L3 fields
  *((u16 *) (ip)) = ctx->ip_tos;
  ip->checksum = ctx->ip4_checksum;

  if (is_last)
    {
      /*
       * This is the last replication in the list.
       * Restore original buffer free functionality.
       */
      vlib_buffer_set_free_list_index (b0, ctx->saved_free_list_index);
      b0->flags &= ~VLIB_BUFFER_RECYCLE;

      /* Free context back to its pool */
      pool_put (rm->contexts[thread_index], ctx);
    }

  return ctx;
}



/*
 * fish pkts back from the recycle queue/freelist
 * un-flatten the context chains
 */
static void
replication_recycle_callback (vlib_main_t * vm, vlib_buffer_free_list_t * fl)
{
  vlib_frame_t *f = 0;
  u32 n_left_from;
  u32 n_left_to_next = 0;
  u32 n_this_frame = 0;
  u32 *from;
  u32 *to_next = 0;
  u32 bi0, pi0;
  vlib_buffer_t *b0;
  int i;
  replication_main_t *rm = &replication_main;
  replication_context_t *ctx;
  u32 feature_node_index = 0;
  uword thread_index = vm->thread_index;

  /*
   * All buffers in the list are destined to the same recycle node.
   * Pull the recycle node index from the first buffer.
   * Note: this could be sped up if the node index were stuffed into
   * the freelist itself.
   */
  if (vec_len (fl->buffers) > 0)
    {
      bi0 = fl->buffers[0];
      b0 = vlib_get_buffer (vm, bi0);
      ctx = pool_elt_at_index (rm->contexts[thread_index], b0->recycle_count);
      feature_node_index = ctx->recycle_node_index;
    }

  /* buffers */
  for (i = 0; i < 2; i++)
    {
      if (i == 0)
	{
	  from = fl->buffers;
	  n_left_from = vec_len (from);
	}

      while (n_left_from > 0)
	{
	  if (PREDIC<style>
@media only all and (prefers-color-scheme: dark) {
.highlight .hll { background-color: #49483e }
.highlight .c { color: #75715e } /* Comment */
.highlight .err { color: #960050; background-color: #1e0010 } /* Error */
.highlight .k { color: #66d9ef } /* Keyword */
.highlight .l { color: #ae81ff } /* Literal */
.highlight .n { color: #f8f8f2 } /* Name */
.highlight .o { color: #f92672 } /* Operator */
.highlight .p { color: #f8f8f2 } /* Punctuation */
.highlight .ch { color: #75715e } /* Comment.Hashbang */
.highlight .cm { color: #75715e } /* Comment.Multiline */
.highlight .cp { color: #75715e } /* Comment.Preproc */
.highlight .cpf { color: #75715e } /* Comment.PreprocFile */
.highlight .c1 { color: #75715e } /* Comment.Single */
.highlight .cs { color: #75715e } /* Comment.Special */
.highlight .gd { color: #f92672 } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .gi { color: #a6e22e } /* Generic.Inserted */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #75715e } /* Generic.Subheading */
.highlight .kc { color: #66d9ef } /* Keyword.Constant */
.highlight .kd { color: #66d9ef } /* Keyword.Declaration */
.highlight .kn { color: #f92672 } /* Keyword.Namespace */
.highlight .kp { color: #66d9ef } /* Keyword.Pseudo */
.highlight .kr { color: #66d9ef } /* Keyword.Reserved */
.highlight .kt { color: #66d9ef } /* Keyword.Type */
.highlight .ld { color: #e6db74 } /* Literal.Date */
.highlight .m { color: #ae81ff } /* Literal.Number */
.highlight .s { color: #e6db74 } /* Literal.String */
.highlight .na { color: #a6e22e } /* Name.Attribute */
.highlight .nb { color: #f8f8f2 } /* Name.Builtin */
.highlight .nc { color: #a6e22e } /* Name.Class */
.highlight .no { color: #66d9ef } /* Name.Constant */
.highlight .nd { color: #a6e22e } /* Name.Decorator */
.highlight .ni { color: #f8f8f2 } /* Name.Entity */
.highlight .ne { color: #a6e22e } /* Name.Exception */
.highlight .nf { color: #a6e22e } /* Name.Function */
.highlight .nl { color: #f8f8f2 } /* Name.Label */
.highlight .nn { color: #f8f8f2 } /* Name.Namespace */
.highlight .nx { color: #a6e22e } /* Nam