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CHG: moved into header files.
[proxmark3-svn] / armsrc / tlv.c
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9206d3b0 1#include <tlv.h>
9206d3b0 2
3int decode_ber_tlv_item(uint8_t* data, tlvtag* returnedtag)
4{
5 uint8_t tag[TAG_LENGTH] = {0x00,0x00};
6 uint16_t length = 0;
7 //uint8_t value[VALUE_LENGTH];
8 uint8_t lenlen = 0;
9 int i = 0;
10 int z = 0;
11 //decode tag
12 tag[0] = data[0];
13 if((tag[0] & TLV_TAG_NUMBER_MASK) == TLV_TAG_NUMBER_MASK) { //see subsequent bytes
14 i++;
15 tag[i] = data[i];
16 //assume tag is only two bytes long for now
17 /*
18 while((data[i] & TLV_TAG_MASK) == TLV_TAG_MASK){
19 i++;
20 tag[i] = data[i];
21 }
22 */
23 }
24 i++;
25 //decode length
26 if((data[i] & TLV_LENGTH_MASK) == TLV_LENGTH_MASK) {
27 lenlen = data[i] ^ TLV_LENGTH_MASK;
28 i++;
29 length = (uint16_t)data[i];
30 z = 1;
31 while(z < lenlen){
32 i++;
33 z++;
34 length <<= 8;
35 length += (uint16_t)data[i];
36 }
37 i++;
38 }
39 else {
40 length = (uint16_t)data[i];
41 i++;
42 }
43 //copy results into the structure and return
44 memcpy(returnedtag->tag, tag, TAG_LENGTH);
45 (*returnedtag).valuelength = length; //return length of tag value
46 (*returnedtag).fieldlength = length + i + 1; //return length of total field
47 memcpy(returnedtag->value, &(data[i]), length);
48 return 0;
49}
50
51//generate a TLV tag off input data
52int encode_ber_tlv_item(uint8_t* tag, uint8_t taglen, uint8_t* data, uint32_t datalen, uint8_t* outputtag, uint32_t* outputtaglen)
53{
54 if(!tag || !data || !outputtag || !outputtaglen) //null pointer check
55 return 0;
56
57 uint8_t datafieldlen = (datalen / 128) + 1; //field length of the tag
58 uint8_t tlvtotallen = taglen + datafieldlen + datalen; //total length of the tag
59 uint8_t returnedtag[tlvtotallen]; //buffer for the returned tag
60 uint8_t counter = 0;
61 memcpy(returnedtag, tag, taglen); //copy tag into buffer
62 counter += taglen;
63 if(datalen < 128){ // 1 byte length value
64 returnedtag[counter++] = datalen;
65 }
66 else{
67 returnedtag[counter++] = datafieldlen | 0x80; //high bit set and number of length bytes
68 for(uint8_t i=datafieldlen; i !=0; i--){
69 returnedtag[counter++] = (datalen >> (i * 8)) & 0xFF; //get current byte
70 }
71 }
72 memcpy(&returnedtag[counter], data, datalen);
73 *outputtaglen = tlvtotallen;
74 memcpy(outputtag, returnedtag,tlvtotallen);
75 return 0;
76}
77
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