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/*
* tlv.c
* Simple TLV implementation.
*
* Copyright (c) 2021 Nikias Bassen, All Rights Reserved.
*
* This 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include "common.h"
#include "libimobiledevice-glue/tlv.h"
#include "endianness.h"
tlv_buf_t tlv_buf_new()
{
tlv_buf_t tlv = malloc(sizeof(struct tlv_buf));
tlv->capacity = 1024;
tlv->length = 0;
tlv->data = malloc(tlv->capacity);
return tlv;
}
void tlv_buf_free(tlv_buf_t tlv)
{
if (tlv) {
free(tlv->data);
free(tlv);
}
}
void tlv_buf_append(tlv_buf_t tlv, uint8_t tag, unsigned int length, void* data)
{
if (!tlv || !tlv->data) {
return;
}
unsigned int req_len = (length > 255) ? (length / 255) * 257 + (2 + (length % 255)) : length;
if (tlv->length + req_len > tlv->capacity) {
unsigned int newcapacity = tlv->capacity + ((req_len / 1024) + 1) * 1024;
unsigned char* newdata = realloc(tlv->data, newcapacity);
if (!newdata) {
fprintf(stderr, "%s: ERROR: Failed to realloc\n", __func__);
return;
}
tlv->data = newdata;
tlv->capacity = newcapacity;
}
unsigned char* p = tlv->data + tlv->length;
unsigned int cur = 0;
while (length - cur > 0) {
if (length - cur > 255) {
*(p++) = tag;
*(p++) = 0xFF;
memcpy(p, (unsigned char*)data + cur, 255);
p += 255;
cur += 255;
} else {
uint8_t rem = length - cur;
*(p++) = tag;
*(p++) = rem;
memcpy(p, (unsigned char*)data + cur, rem);
p += rem;
cur += rem;
}
}
tlv->length = p - tlv->data;
}
unsigned char* tlv_get_data_ptr(const void* tlv_data, void* tlv_end, uint8_t tag, uint8_t* length)
{
unsigned char* p = (unsigned char*)tlv_data;
unsigned char* end = (unsigned char*)tlv_end;
while (p < end) {
uint8_t cur_tag = *(p++);
uint8_t len = *(p++);
if (cur_tag == tag) {
*length = len;
return p;
}
p+=len;
}
return NULL;
}
int tlv_data_get_uint(const void* tlv_data, unsigned int tlv_length, uint8_t tag, uint64_t* value)
{
if (!tlv_data || tlv_length < 2 || !value) {
return 0;
}
uint8_t length = 0;
unsigned char* ptr = tlv_get_data_ptr(tlv_data, (unsigned char*)tlv_data+tlv_length, tag, &length);
if (!ptr) {
return 0;
}
if (ptr + length > (unsigned char*)tlv_data + tlv_length) {
return 0;
}
if (length == 1) {
uint8_t val = *ptr;
*value = val;
} else if (length == 2) {
uint16_t val = *(uint16_t*)ptr;
val = le16toh(val);
*value = val;
} else if (length == 4) {
uint32_t val = *(uint32_t*)ptr;
val = le32toh(val);
*value = val;
} else if (length == 8) {
uint64_t val = *(uint64_t*)ptr;
val = le64toh(val);
*value = val;
} else {
return 0;
}
return 1;
}
int tlv_data_get_uint8(const void* tlv_data, unsigned int tlv_length, uint8_t tag, uint8_t* value)
{
if (!tlv_data || tlv_length < 2 || !value) {
return 0;
}
uint8_t length = 0;
unsigned char* ptr = tlv_get_data_ptr(tlv_data, (unsigned char*)tlv_data+tlv_length, tag, &length);
if (!ptr) {
return 0;
}
if (length != 1) {
return 0;
}
if (ptr + length > (unsigned char*)tlv_data + tlv_length) {
return 0;
}
*value = *ptr;
return 1;
}
int tlv_data_copy_data(const void* tlv_data, unsigned int tlv_length, uint8_t tag, void** out, unsigned int* out_len)
{
if (!tlv_data || tlv_length < 2 || !out || !out_len) {
return 0;
}
*out = NULL;
*out_len = 0;
unsigned char* dest = NULL;
unsigned int dest_len = 0;
unsigned char* ptr = (unsigned char*)tlv_data;
unsigned char* end = (unsigned char*)tlv_data + tlv_length;
while (ptr < end) {
uint8_t length = 0;
ptr = tlv_get_data_ptr(ptr, end, tag, &length);
if (!ptr) {
break;
}
unsigned char* newdest = realloc(dest, dest_len + length);
if (!newdest) {
free(dest);
return 0;
}
dest = newdest;
memcpy(dest + dest_len, ptr, length);
dest_len += length;
ptr += length;
}
if (!dest) {
return 0;
}
*out = (void*)dest;
*out_len = dest_len;
return 1;
}
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