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P25 Moto Alias vPDU Working; Tweaks and Fixes;

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lwvmobile
2025-02-06 21:36:01 -05:00
parent f0657ee5a8
commit 0cbf42e4e6
3 changed files with 116 additions and 39 deletions
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123
src/dsd_alias.c
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@@ -8,7 +8,7 @@
#include "dsd.h"
//Motorola P25 OTA Alias Decoding ripped/demistified from Ilya Smirnov's SDRTrunk Voodoo Code
//Motorola P25 OTA Alias Decoding ripped/demystified from Ilya Smirnov's SDRTrunk Voodoo Code
uint8_t moto_alias_lut[256] = {
0xD2, 0xF6, 0xD4, 0x2B, 0x63, 0x49, 0x94, 0x5E, 0xA7, 0x5C, 0x70, 0x69, 0xF7, 0x08, 0xB1, 0x7D,
0x38, 0xCF, 0xCC, 0xD8, 0x51, 0x8F, 0xD5, 0x93, 0x6A, 0xF3, 0xEF, 0x7E, 0xFB, 0x64, 0xF4, 0x35,
@@ -93,7 +93,9 @@ void apx_embedded_alias_header_phase1 (dsd_opts * opts, dsd_state * state, uint8
UNUSED(opts);
uint8_t ta_len = (uint8_t)ConvertBitIntoBytes(&lc_bits[32], 8); //len in blocks of associated talker alias
fprintf (stderr, " Block Len: %d;", ta_len);
uint8_t sn = (uint8_t)ConvertBitIntoBytes(&lc_bits[56], 4);
fprintf (stderr, " SN: %X;", sn);
fprintf (stderr, " BN: 0/%d;", ta_len);
//use dmr_pdu_sf for storage, store entire header (will be used to verify complete reception of full alias)
memset (state->dmr_pdu_sf[slot], 0, sizeof (state->dmr_pdu_sf[slot])); //reset storage for header and blocks
@@ -138,13 +140,35 @@ void apx_embedded_alias_blocks_phase1 (dsd_opts * opts, dsd_state * state, uint8
if (ta_len == bn) //this is the last block, proceed to decoding
{
int16_t num_bits = bn * 44; //number of relevant data bits total from all blocks (not including header)
//WIP: Need a way to calculate variable len bits determined by a bit counter or something
// int16_t num_bits = bn * 44; //number of relevant data bits total from all blocks (not including header)
int16_t num_bits = 56; //starting value is the static bit count on the fqsuid
// //evaluate the storage and determine how many octets/bits are present at this point (fall back to this if needed)
// for (int16_t i = 0; i < 31; i++) //end point? BEE00 doesn't trip this since it is 0xBE 0xE0 0x0X, but other things might, may want to start after the fqsuid
// {
// uint8_t byte = (uint8_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][72+56+(i*8)], 8);
// if (byte == 0)
// break;
// else
// num_bits += 8;
// }
//evaluate the storage and determine how many octets/bits are present at this point (expanded to two octets each, CRC with a 00xx pattern failed this)
for (int16_t i = 0; i < 31; i++) //end point? BEE00 doesn't trip this since it is 0xBE 0xE0 0x0X, but other things might, may want to start after the fqsuid
{
uint16_t bytes = (uint16_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][72+56+(i*16)], 16);
if (bytes == 0)
break;
else
num_bits += 16;
}
//pass to alias decoder
apx_embedded_alias_decode (opts, state, slot, num_bits, state->dmr_pdu_sf[slot]);
//clear out now stale storage
memset (state->dmr_pdu_sf[slot], 0, sizeof (state->dmr_pdu_sf[slot]));
memset (state->dmr_pdu_sf[slot], 0, sizeof(state->dmr_pdu_sf[slot]));
}
}
@@ -152,37 +176,56 @@ void apx_embedded_alias_blocks_phase1 (dsd_opts * opts, dsd_state * state, uint8
void apx_embedded_alias_header_phase2 (dsd_opts * opts, dsd_state * state, uint8_t slot, uint8_t * lc_bits)
{
//TODO: Adjust values as needed for MAC vPDU Messages
UNUSED(opts);
uint8_t ta_len = (uint8_t)ConvertBitIntoBytes(&lc_bits[32], 8); //adjust when samples arrive with this in them
fprintf (stderr, " Block Len: %d;", ta_len);
uint8_t ta_len = (uint8_t)ConvertBitIntoBytes(&lc_bits[40], 8);
uint8_t sn = (uint8_t)ConvertBitIntoBytes(&lc_bits[64], 4);
uint8_t bn = (uint8_t)ConvertBitIntoBytes(&lc_bits[56], 8);
fprintf (stderr, " SN: %X;", sn); //NOTE: vPDU header is also a partial block, and has a block num and SN value in it
fprintf (stderr, " BN: %d/%d;", bn, ta_len);
//bit array to rearrange input lc_bits from phase 2 mac to match the phase 1 header and block handling
uint8_t bits[136]; memset(bits, 0, sizeof(bits));
memcpy (bits, lc_bits, 2*8*sizeof(uint8_t)); //header 0x9190
memcpy (bits+16, lc_bits+24, 4*8*sizeof(uint8_t)); //BN, SN, etc
memcpy (bits+56, lc_bits+56, 10*8*sizeof(uint8_t)); //adding 8 bits of extra padding here
int16_t alias_st = 136; //start of the encoded alias (the copied size of this header, basically)
//debug, dump header arranged at this end
// fprintf (stderr, " Header: ");
// for (int16_t i = 0; i < alias_st/8; i++) //double check and adjust
// fprintf (stderr, "%02X", (uint8_t)ConvertBitIntoBytes(&bits[0+(i*8)], 8));
//use dmr_pdu_sf for storage, store entire header (will be used to verify complete reception of full alias)
memset (state->dmr_pdu_sf[slot], 0, sizeof (state->dmr_pdu_sf[slot])); //reset storage for header and blocks
memcpy (state->dmr_pdu_sf[slot], lc_bits, 72*sizeof(uint8_t));
memcpy (state->dmr_pdu_sf[slot], bits, alias_st*sizeof(uint8_t)); //this header block has 128 bits of relevant data (through the fqsuid)
}
void apx_embedded_alias_blocks_phase2 (dsd_opts * opts, dsd_state * state, uint8_t slot, uint8_t * lc_bits)
{
//TODO: Adjust values as needed for MAC vPDU Messages
//WIP: Adjust values as needed for MAC vPDU Messages
UNUSED(opts);
uint8_t bn = (uint8_t)ConvertBitIntoBytes(&lc_bits[16], 8); //current block number
uint8_t sn = (uint8_t)ConvertBitIntoBytes(&lc_bits[24], 4); //is a static value on all block sequences
int16_t rel_bits = 100; //number of relevant bits in each block
int16_t rel_st = 36; //start of relevant bits in this block
int16_t alias_st = 136; //start of the encoded alias
uint8_t bn = (uint8_t)ConvertBitIntoBytes(&lc_bits[24], 8); //current block number
uint8_t sn = (uint8_t)ConvertBitIntoBytes(&lc_bits[32], 4); //is a static value on all block sequences
uint8_t ta_len = (uint8_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][32], 8); //len in blocks pulled from stored header
uint16_t header = (uint16_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][0], 16); //header check, should be 0x1590
uint16_t header = (uint16_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][0], 16); //header check, should be 0x9190
if (ta_len == 0 || header != 0x1590) //checkdown, make sure we have an up to date header for this with a good len value
if (ta_len == 0 || header != 0x9190)
{
fprintf (stderr, " Missing Header");
fprintf (stderr, " BN: %d/??;", bn);
fprintf (stderr, " SN: %X;", sn);
fprintf (stderr, " Partial: ");
for (uint8_t i = 7; i < 18; i++) //Fix this value when samples arrive
for (uint8_t i = 9; i < 32; i++) //double check and adjust
fprintf (stderr, "%0X", (uint8_t)ConvertBitIntoBytes(&lc_bits[0+(i*4)], 4));
//clear out now stale storage
memset (state->dmr_pdu_sf[slot], 0, sizeof (state->dmr_pdu_sf[slot]));
memset (state->dmr_pdu_sf[slot], 0, sizeof(state->dmr_pdu_sf[slot]));
}
else //good len and header stored
@@ -194,14 +237,40 @@ void apx_embedded_alias_blocks_phase2 (dsd_opts * opts, dsd_state * state, uint8
fprintf (stderr, " SN: %X;", sn);
fprintf (stderr, " BN: %d/%d;", bn, ta_len);
//use dmr_pdu_sf for storage, store data relevant portion at ptr of (bn-1) * 44 + 72 offset for header
memcpy(state->dmr_pdu_sf[slot]+(((bn-1)*44)+72), lc_bits+28, 44*sizeof(uint8_t)); //Fix this value when samples arrive
//use dmr_pdu_sf for storage, store data relevant portion at ptr calculated below
memcpy(state->dmr_pdu_sf[slot]+(alias_st+((bn-1)*rel_bits)), lc_bits+rel_st, rel_bits*sizeof(uint8_t)); //Fix this value when samples arrive
//debug, dump accumulated data at this end
// fprintf (stderr, " Accumulated: ");
// for (int16_t i = 0; i < (alias_st+(rel_bits*bn))/8; i++) //double check and adjust
// fprintf (stderr, "%02X", (uint8_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][0+(i*8)], 8));
if (ta_len == bn) //this is the last block, proceed to decoding
{
//Fix this value when samples arrive
int16_t num_bits = bn * 48; //number of relevant data bits total from all blocks (not including header)
//WIP: Need a way to calculate variable len bits determined by a bit counter or something
// int16_t num_bits = (bn * rel_bits) + 56; //number of relevant data bits total from all blocks (including header fqsuid stub)
int16_t num_bits = 56; //starting value is the static bit count on the fqsuid
// //evaluate the storage and determine how many octets/bits are present at this point (fall back to this if needed)
// for (int16_t i = 0; i < 31; i++) //end point? BEE00 doesn't trip this since it is 0xBE 0xE0 0x0X, but other things might, may want to start after the fqsuid
// {
// uint8_t byte = (uint8_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][72+56+(i*8)], 8);
// if (byte == 0)
// break;
// else
// num_bits += 8;
// }
//evaluate the storage and determine how many octets/bits are present at this point (expanded to two octets each, CRC with a 00xx pattern failed this)
for (int16_t i = 0; i < 31; i++) //end point? BEE00 doesn't trip this since it is 0xBE 0xE0 0x0X, but other things might, may want to start after the fqsuid
{
uint16_t bytes = (uint16_t)ConvertBitIntoBytes(&state->dmr_pdu_sf[slot][72+56+(i*16)], 16);
if (bytes == 0)
break;
else
num_bits += 16;
}
//pass to alias decoder
apx_embedded_alias_decode (opts, state, slot, num_bits, state->dmr_pdu_sf[slot]);
@@ -220,9 +289,6 @@ void apx_embedded_alias_decode (dsd_opts * opts, dsd_state * state, uint8_t slot
UNUSED(state);
UNUSED(slot);
//debug, let's look at byte, bit counts and see if we can find this in the completed dump
// fprintf (stderr, " Bits: %X; Bytes: %X; Mod: %d; ", num_bits, num_bits/8, num_bits%8);
//debug, dump completed data set
// fprintf (stderr, "\n Full: ");
// for (int16_t i = 0; i < (72+num_bits)/4; i++)
@@ -250,7 +316,7 @@ void apx_embedded_alias_decode (dsd_opts * opts, dsd_state * state, uint8_t slot
uint32_t rid = (uint32_t)ConvertBitIntoBytes(&input[104], 24);
//print fully qualified SUID
fprintf (stderr, "\n FQ-SUID: %05X.%03X.%X (%d);", wacn, sys, rid, rid);
fprintf (stderr, "\n FQ-SUID: %05X.%03X.%06X (%d);", wacn, sys, rid, rid);
//WIP: Working, needs more samples to verify various num_bits values
uint16_t ptr = 128; //starting point of encoded data from test vectors
@@ -314,10 +380,17 @@ void apx_embedded_alias_decode (dsd_opts * opts, dsd_state * state, uint8_t slot
for (int16_t i = 0; i < num_bytes/2; i++)
fprintf (stderr, "%lc", ((decoded[(i*2)+0])<<8) | ((decoded[(i*2)+1])<<0) );
//For Ncurses Display (needs to be testing on real samples first to make sure this is setup right)
// memcpy (state->dmr_embedded_gps[slot], decoded, bytes*sizeof(uint8_t));
//For Ncurses Display (needs to be testing on real samples first to make sure this is setup right, %s doesn't seem to work well with utf16)
// memcpy (state->dmr_embedded_gps[slot], decoded, num_bytes*sizeof(uint8_t));
// state->dmr_embedded_gps[slot][199] = '\0'; //terminate string
//For Ncurses Display (kind of a hack, but will only work if the UTF16 chars are just roman alphanumerical UTF8 compatible)
for (int16_t i = 0; i < num_bytes/2; i++)
state->dmr_embedded_gps[slot][i] = decoded[(i*2)+1];
//TODO: Do this like the Harris Talker Alias so it
//can read/write to the files and not randomly reset
//and flicker each time its decoded
}
}