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/* -*- c-basic-offset: 8 -*-
rdesktop: A Remote Desktop Protocol client.
ASN.1 utility functions
Copyright 2012-2017 Henrik Andersson <hean01@cendio.se> for Cendio AB
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "rdesktop.h"
/* Parse an ASN.1 BER header */
RD_BOOL
ber_parse_header(STREAM s, int tagval, int *length)
{
int tag, len;
if (tagval > 0xff)
{
in_uint16_be(s, tag);
}
else
{
in_uint8(s, tag);
}
if (tag != tagval)
{
logger(Core, Error, "ber_parse_header(), expected tag %d, got %d", tagval, tag);
return False;
}
in_uint8(s, len);
if (len & 0x80)
{
len &= ~0x80;
*length = 0;
while (len--)
next_be(s, *length);
}
else
*length = len;
return s_check(s);
}
void
ber_out_sequence(STREAM out, STREAM content)
{
size_t length;
length = (content ? s_length(content) : 0);
ber_out_header(out, BER_TAG_SEQUENCE | BER_TAG_CONSTRUCTED, length);
if (content)
out_stream(out, content);
}
/* Output an ASN.1 BER header */
void
ber_out_header(STREAM s, int tagval, int length)
{
if (tagval > 0xff)
{
out_uint16_be(s, tagval);
}
else
{
out_uint8(s, tagval);
}
if (length >= 0x80)
{
out_uint8(s, 0x82);
out_uint16_be(s, length);
}
else
out_uint8(s, length);
}
/* Output an ASN.1 BER integer */
void
ber_out_integer(STREAM s, int value)
{
ber_out_header(s, BER_TAG_INTEGER, 2);
out_uint16_be(s, value);
}
RD_BOOL
ber_in_header(STREAM s, int *tagval, int *decoded_len)
{
in_uint8(s, *tagval);
in_uint8(s, *decoded_len);
if (*decoded_len < 0x80)
return True;
else if (*decoded_len == 0x81)
{
in_uint8(s, *decoded_len);
return True;
}
else if (*decoded_len == 0x82)
{
in_uint16_be(s, *decoded_len);
return True;
}
return False;
}
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