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/*
* Copyright 2013 Google Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/*
* Author: ncardwell@google.com (Neal Cardwell)
*
* Implementation for reading and writing TCP options in their wire format.
*/
#include "tcp_options.h"
#include <stdlib.h>
#include <string.h>
#include "packet.h"
struct tcp_options *tcp_options_new(void)
{
return calloc(1, sizeof(struct tcp_options));
}
struct tcp_option *tcp_option_new(u8 kind, u8 length)
{
struct tcp_option *option = calloc(1, sizeof(struct tcp_option));
option->kind = kind;
option->length = length;
return option;
}
int tcp_options_append(struct tcp_options *options,
struct tcp_option *option)
{
if (options->length + option->length > sizeof(options->data))
return STATUS_ERR;
memcpy(options->data + options->length, option, option->length);
options->length += option->length;
assert(options->length <= sizeof(options->data));
free(option);
return STATUS_OK;
}
int num_sack_blocks(u8 opt_len, int *num_blocks, char **error)
{
if (opt_len <= 2) {
asprintf(error, "TCP SACK option too short");
return STATUS_ERR;
}
const int num_bytes = opt_len - 2;
if (num_bytes % sizeof(struct sack_block) != 0) {
asprintf(error,
"TCP SACK option not a multiple of SACK block size");
return STATUS_ERR;
}
*num_blocks = num_bytes / sizeof(struct sack_block);
return STATUS_OK;
}
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