replication.h

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/*
 * replication.h : 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.
 */

#ifndef included_replication_h
#define included_replication_h


#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vnet/replication.h>


typedef struct {

  // The entire vnet buffer header restored for each replica
  u8   vnet_buffer[32];      // 16B aligned to allow vector unit copy
  u8   reserved[32];         // space for future expansion of vnet buffer header

  // feature state used during this replication
  u64  feature_replicas;     // feature's id for its set of replicas
  u32  feature_counter;      // feature's current index into set of replicas
  u32  recycle_node_index;   // feature's recycle node index

  // data saved from the start of replication and restored at the end of replication
  u32  saved_clone_count;     // from vlib buffer
  u32  saved_free_list_index; // from vlib buffer

  // data saved from the original packet and restored for each replica
  u64  l2_header[3];         // 24B (must be at least 22B for l2 packets)
  u16  ip_tos;               // v4 and v6
  u16  ip4_checksum;         // needed for v4 only

  // data saved from the vlib buffer header and restored for each replica
  i16  current_data;         // offset of first byte of packet in packet data
  u8   pad[6];               // to 64B
  u8   l2_packet;            // flag for l2 vs l3 packet data

} replication_context_t;    // 128B


typedef struct {

  u32 recycle_list_index;

  // per-thread pools of replication contexts
  replication_context_t ** contexts;

  vlib_main_t * vlib_main;
  vnet_main_t * vnet_main;

} replication_main_t;


extern replication_main_t replication_main;


// Return 1 if this buffer just came from the replication recycle handler.
always_inline u32
replication_is_recycled (vlib_buffer_t * b0)
{
  return b0->flags & VLIB_BUFFER_IS_RECYCLED;
}

// Clear the recycle flag. If buffer came from the replication recycle
// handler, this flag must be cleared before the packet is transmitted again.
always_inline void
replication_clear_recycled (vlib_buffer_t * b0)
{
  b0->flags &= ~VLIB_BUFFER_IS_RECYCLED;
}

// Return the active replication context if this buffer has 
// been recycled, otherwise return 0. (Note that this essentially
// restricts access to the replication context to the replication
// feature's prep and recycle nodes.)
always_inline replication_context_t *
replication_get_ctx (vlib_buffer_t * b0)
{
  replication_main_t * rm = &replication_main;

  return replication_is_recycled (b0) ? 
   pool_elt_at_index (rm->contexts[os_get_cpu_number()], b0->clone_count) :
   0;
}

// Prefetch the replication context for this buffer, if it exists
always_inline void
replication_prefetch_ctx (vlib_buffer_t * b0)
{
  replication_context_t *ctx = replication_get_ctx (b0);

  if (ctx) {
    CLIB_PREFETCH (ctx, (2*CLIB_CACHE_LINE_BYTES), STORE);
  }
}

replication_context_t *
replication_prep (vlib_main_t * vm,
                  vlib_buffer_t * b0,
                  u32 recycle_node_index,
                  u32 l2_packet);

replication_context_t *
replication_recycle (vlib_main_t * vm,
                     vlib_buffer_t * b0,
                     u32 is_last);


#endif