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/*
* Off-the-Record Messaging library
* Copyright (C) 2004-2012 Ian Goldberg, Chris Alexander, Willy Lew,
* Nikita Borisov
* <otr@cypherpunks.ca>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of version 2.1 of the GNU Lesser General
* Public License as published by the Free Software Foundation.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "tlv.h"
/* Make a single TLV, copying the supplied data */
OtrlTLV *otrl_tlv_new(unsigned short type, unsigned short len,
const unsigned char *data)
{
OtrlTLV *tlv = malloc(sizeof(OtrlTLV));
assert(tlv != NULL);
tlv->type = type;
tlv->len = len;
tlv->data = malloc(len + 1);
assert(tlv->data != NULL);
memmove(tlv->data, data, len);
tlv->data[tlv->len] = '\0';
tlv->next = NULL;
return tlv;
}
/* Construct a chain of TLVs from the given data */
OtrlTLV *otrl_tlv_parse(const unsigned char *serialized, size_t seriallen)
{
OtrlTLV *tlv = NULL;
OtrlTLV **tlvp = &tlv;
while (seriallen >= 4) {
unsigned short type = (serialized[0] << 8) + serialized[1];
unsigned short len = (serialized[2] << 8) + serialized[3];
serialized += 4; seriallen -=4;
if (seriallen < len) break;
*tlvp = otrl_tlv_new(type, len, serialized);
serialized += len;
seriallen -= len;
tlvp = &((*tlvp)->next);
}
return tlv;
}
/* Deallocate a chain of TLVs */
void otrl_tlv_free(OtrlTLV *tlv)
{
while (tlv) {
OtrlTLV *next = tlv->next;
free(tlv->data);
free(tlv);
tlv = next;
}
}
/* Find the serialized length of a chain of TLVs */
size_t otrl_tlv_seriallen(const OtrlTLV *tlv)
{
size_t totlen = 0;
while (tlv) {
totlen += tlv->len + 4;
tlv = tlv->next;
}
return totlen;
}
/* Serialize a chain of TLVs. The supplied buffer must already be large
* enough. */
void otrl_tlv_serialize(unsigned char *buf, const OtrlTLV *tlv)
{
while (tlv) {
buf[0] = (tlv->type >> 8) & 0xff;
buf[1] = tlv->type & 0xff;
buf[2] = (tlv->len >> 8) & 0xff;
buf[3] = tlv->len & 0xff;
buf += 4;
memmove(buf, tlv->data, tlv->len);
buf += tlv->len;
tlv = tlv->next;
}
}
/* Return the first TLV with the given type in the chain, or NULL if one
* isn't found. (The tlvs argument isn't const because the return type
* needs to be non-const.) */
OtrlTLV *otrl_tlv_find(OtrlTLV *tlvs, unsigned short type)
{
while (tlvs) {
if (tlvs->type == type) return tlvs;
tlvs = tlvs->next;
}
return NULL;
}
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