pg.c

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/*
 * pg.c: packet generator for L2TPv3 header
 *
 * 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/pg/pg.h>
#include <vnet/l2tp/l2tp.h>

typedef struct {
  pg_edit_t session_id;
  pg_edit_t cookie;
} pg_l2tp_header_t;

typedef struct {
  pg_edit_t l2_sublayer;
} pg_l2tp_header_l2_sublayer_t;

static inline void
pg_l2tp_header_init (pg_l2tp_header_t * e)
{
  pg_edit_init (&e->session_id, l2tpv3_header_t, session_id);
  pg_edit_init (&e->cookie, l2tpv3_header_t, cookie);
}

uword
unformat_pg_l2tp_header (unformat_input_t * input, va_list * args)
{
  pg_stream_t * s = va_arg (*args, pg_stream_t *);
  pg_l2tp_header_t * h;
  u32 group_index, error;
  vlib_main_t * vm = vlib_get_main();

  h = pg_create_edit_group (s, sizeof (h[0]), 
                            sizeof (l2tpv3_header_t) - sizeof(u32),
                            &group_index);
  pg_l2tp_header_init (h);

  error = 1;

  // session id and cookie are required
  if (! unformat (input, "L2TP: session_id %U cookie %U",
                  unformat_pg_edit, unformat_pg_number, &h->session_id,
                  unformat_pg_edit, unformat_pg_number, &h->cookie)) {
    goto done;
  }

  // "l2_sublayer <value>" is optional
  if (unformat (input, "l2_sublayer")) {
    pg_l2tp_header_l2_sublayer_t * h2;

    h2 = pg_add_edits (s, sizeof (h2[0]), sizeof(u32), group_index);
    pg_edit_init (&h2->l2_sublayer, l2tpv3_header_t, l2_specific_sublayer);
    if (! unformat_user (input, unformat_pg_edit,
                         unformat_pg_number, &h2->l2_sublayer)) {
      goto done;
    } 
  }

  // Parse an ethernet header if it is present
  {
    pg_node_t * pg_node = 0;
    vlib_node_t * eth_lookup_node;

    eth_lookup_node = vlib_get_node_by_name (vm, (u8 *)"ethernet-input");
    ASSERT (eth_lookup_node);

    pg_node = pg_get_node (eth_lookup_node->index);

    if (pg_node && pg_node->unformat_edit
        && unformat_user (input, pg_node->unformat_edit, s))
      ;
  }

  error = 0;

done:
  if (error)
    pg_free_edit_group (s);
  return error == 0;
}