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/*
* Copyright (C) 2001 Nikos Mavroyanopoulos
*
* This file is part of GNUTLS.
*
* The GNUTLS library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* This file contains the code for the Max Record Size TLS extension.
*/
#include "gnutls_int.h"
#include "gnutls_errors.h"
#include "gnutls_num.h"
#include <ext_max_record.h>
/*
* In case of a server: if a MAX_RECORD_SIZE extension type is received then it stores
* into the session the new value. The server may use gnutls_get_max_record_size(),
* in order to access it.
*
* In case of a client: If a different max record size (than the default) has
* been specified then it sends the extension.
*
*/
int _gnutls_max_record_recv_params( gnutls_session session, const opaque* data, int data_size) {
ssize_t new_size;
if (session->security_parameters.entity == GNUTLS_SERVER) {
if (data_size > 0) {
DECR_LEN( data_size, 1);
new_size = _gnutls_mre_num2record(data[0]);
if (new_size < 0) {
gnutls_assert();
return new_size;
}
session->security_parameters.max_record_send_size = new_size;
session->security_parameters.max_record_recv_size = new_size;
}
} else { /* CLIENT SIDE - we must check if the sent record size is the right one
*/
if (data_size > 0) {
if ( data_size != 1) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
new_size = _gnutls_mre_num2record(data[0]);
if (new_size < 0 || new_size != session->internals.proposed_record_size) {
gnutls_assert();
return GNUTLS_E_ILLEGAL_PARAMETER;
} else {
session->security_parameters.max_record_recv_size = session->internals.proposed_record_size;
}
}
}
return 0;
}
/* returns data_size or a negative number on failure
* data is allocated localy
*/
int _gnutls_max_record_send_params( gnutls_session session, opaque* data, int data_size) {
uint16 len;
/* this function sends the client extension data (dnsname) */
if (session->security_parameters.entity == GNUTLS_CLIENT) {
if (session->internals.proposed_record_size != DEFAULT_MAX_RECORD_SIZE) {
gnutls_assert();
len = 1;
if (data_size < len) {
gnutls_assert();
return GNUTLS_E_INVALID_REQUEST;
}
data[0] = (uint8) _gnutls_mre_record2num( session->internals.proposed_record_size);
return len;
}
} else { /* server side */
if (session->security_parameters.max_record_recv_size != DEFAULT_MAX_RECORD_SIZE) {
len = 1;
if (data_size < len) {
gnutls_assert();
return GNUTLS_E_INVALID_REQUEST;
}
data[0] = (uint8) _gnutls_mre_record2num( session->security_parameters.max_record_recv_size);
return len;
}
}
return 0;
}
/* Maps numbers to record sizes according to the
* extensions draft.
*/
int _gnutls_mre_num2record( int num) {
switch( num) {
case 1:
return 512;
case 2:
return 1024;
case 3:
return 2048;
case 4:
return 4096;
default:
return GNUTLS_E_ILLEGAL_PARAMETER;
}
}
/* Maps record size to numbers according to the
* extensions draft.
*/
int _gnutls_mre_record2num( uint16 record_size) {
switch(record_size) {
case 512:
return 1;
case 1024:
return 2;
case 2048:
return 3;
case 4096:
return 4;
default:
return GNUTLS_E_ILLEGAL_PARAMETER;
}
}
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