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dsd-fme/src/dmr_le.c
lwvmobile 8ccaf2d261 DMR LE ENC Identifiers Tweak;
2023-07-03 12:31:58 -04:00

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/*-------------------------------------------------------------------------------
* dmr_le.c
* DMR Late Entry MI Fragment Assembly, Procesing, and related Alg functions
*
* LWVMOBILE
* 2022-12 DSD-FME Florida Man Edition
*-----------------------------------------------------------------------------*/
#include "dsd.h"
//gather ambe_fr mi fragments for processing
void dmr_late_entry_mi_fragment (dsd_opts * opts, dsd_state * state, uint8_t vc, char ambe_fr[4][24], char ambe_fr2[4][24], char ambe_fr3[4][24])
{
uint8_t slot = state->currentslot;
//enforce RC4 due to missing PI header, but with valid SVC Opts
//ideally, this would be handled by VC-F single burst, but its not fully reliable compared to this
//due to multiple signalling occurring inside of it, depending on system type
if (state->M == 0x21)
{
if (slot == 0 && state->dmr_so & 0x40)
{
state->payload_algid = 0x21;
state->payload_keyid = 0xFF;
}
if (slot == 1 && state->dmr_soR & 0x40)
{
state->payload_algidR = 0x21;
state->payload_keyidR = 0xFF;
}
}
//collect our fragments and place them into storage
state->late_entry_mi_fragment[slot][vc][0] = (uint64_t)ConvertBitIntoBytes(&ambe_fr[3][0], 4);
state->late_entry_mi_fragment[slot][vc][1] = (uint64_t)ConvertBitIntoBytes(&ambe_fr2[3][0], 4);
state->late_entry_mi_fragment[slot][vc][2] = (uint64_t)ConvertBitIntoBytes(&ambe_fr3[3][0], 4);
if (vc == 6) dmr_late_entry_mi (opts, state);
}
void dmr_late_entry_mi (dsd_opts * opts, dsd_state * state)
{
uint8_t slot = state->currentslot;
int i, j;
int g[3];
unsigned char mi_go_bits[24];
uint64_t mi_test = 0;
uint64_t go_test = 0;
uint64_t mi_corrected = 0;
uint64_t go_corrected = 0;
mi_test = (state->late_entry_mi_fragment[slot][1][0] << 32L) | (state->late_entry_mi_fragment[slot][2][0] << 28) | (state->late_entry_mi_fragment[slot][3][0] << 24) |
(state->late_entry_mi_fragment[slot][1][1] << 20) | (state->late_entry_mi_fragment[slot][2][1] << 16) | (state->late_entry_mi_fragment[slot][3][1] << 12) |
(state->late_entry_mi_fragment[slot][1][2] << 8) | (state->late_entry_mi_fragment[slot][2][2] << 4) | (state->late_entry_mi_fragment[slot][3][2] << 0);
go_test = (state->late_entry_mi_fragment[slot][4][0] << 32L) | (state->late_entry_mi_fragment[slot][5][0] << 28) | (state->late_entry_mi_fragment[slot][6][0] << 24) |
(state->late_entry_mi_fragment[slot][4][1] << 20) | (state->late_entry_mi_fragment[slot][5][1] << 16) | (state->late_entry_mi_fragment[slot][6][1] << 12) |
(state->late_entry_mi_fragment[slot][4][2] << 8) | (state->late_entry_mi_fragment[slot][5][2] << 4) | (state->late_entry_mi_fragment[slot][6][2] << 0);
for (j = 0; j < 3; j++)
{
for (i = 0; i < 12; i++)
{
mi_go_bits[i] = (( mi_test << (i+j*12) ) & 0x800000000) >> 35;
mi_go_bits[i+12] = (( go_test << (i+j*12) ) & 0x800000000) >> 35;
}
//execute golay decode and assign pass or fail to g
if ( Golay_24_12_decode(mi_go_bits) ) g[j] = 1;
else g[j] = 0;
for (i = 0; i < 12; i++)
{
mi_corrected = mi_corrected << 1;
mi_corrected |= mi_go_bits[i];
go_corrected = go_corrected << 1;
go_corrected |= mi_go_bits[i+12];
}
}
int mi_final = 0;
mi_final = (mi_corrected >> 4) & 0xFFFFFFFF;
if (g[0] && g[1] && g[2])
{
if (slot == 0 && state->payload_algid != 0)
{
if (state->payload_mi != mi_final)
{
fprintf (stderr, "%s", KCYN);
fprintf (stderr, " Slot 1 PI/LFSR and Late Entry MI Mismatch - %08X : %08X \n", state->payload_mi, mi_final);
state->payload_mi = mi_final;
fprintf (stderr, "%s", KNRM);
}
//run afterwards, or le verification won't match up properly
if (state->payload_algid != 0x21)
{
LFSR64 (state);
fprintf (stderr, "\n");
}
}
if (slot == 1 && state->payload_algidR != 0)
{
if (state->payload_miR != mi_final)
{
fprintf (stderr, "%s", KCYN);
fprintf (stderr, " Slot 2 PI/LFSR and Late Entry MI Mismatch - %08X : %08X \n", state->payload_miR, mi_final);
state->payload_miR = mi_final;
fprintf (stderr, "%s", KNRM);
}
//run afterwards, or le verification won't match up properly
if (state->payload_algidR != 0x21)
{
LFSR64 (state);
fprintf (stderr, "\n");
}
}
}
}
void dmr_alg_refresh (dsd_opts * opts, dsd_state * state)
{
if (state->currentslot == 0)
{
state->dropL = 256;
if (state->K1 != 0)
{
state->DMRvcL = 0;
}
if (state->payload_algid == 0x21)
{
LFSR (state);
fprintf (stderr, "\n");
}
//LFSR64 carried out after LE verification in order to keep it from constantly resetting the MI to the previous value
}
if (state->currentslot == 1)
{
state->dropR = 256;
if (state->K1 != 0)
{
state->DMRvcR = 0;
}
if (state->payload_algidR == 0x21)
{
LFSR (state);
fprintf (stderr, "\n");
}
//LFSR64 carried out after LE verification in order to keep it from constantly resetting the MI to the previous value
}
}
void dmr_alg_reset (dsd_opts * opts, dsd_state * state)
{
state->dropL = 256;
state->dropR = 256;
state->DMRvcL = 0;
state->DMRvcR = 0;
state->payload_miP = 0;
state->payload_miN = 0;
}
//handle Single Burst (Voice Burst F) or Reverse Channel Signalling
void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power)
{
int i;
uint8_t slot = state->currentslot;
uint8_t sbrc_interleaved[32];
uint8_t sbrc_return[32];
uint8_t sbrc_retcrc[32]; //crc significant bits of the return for SB
memset (sbrc_interleaved, 0, sizeof(sbrc_interleaved));
memset (sbrc_return, 0, sizeof(sbrc_return));
memset (sbrc_retcrc, 0, sizeof(sbrc_retcrc));
uint32_t irr_err = 0;
uint32_t sbrc_hex = 0;
uint16_t crc_extracted = 7777;
uint16_t crc_computed = 9999;
uint8_t crc7_okay = 0; //RC
uint8_t crc3_okay = 0; //TXI
uint8_t txi = 0; //SEE: https://patents.google.com/patent/US8271009B2
//NOTE: Any previous mentions to Cap+ in this area may have been in error,
//The signalling observed here was actually TXI information, not Cap+ Specifically
//check to see if this a TXI system
if (slot == 0 && state->dmr_so & 0x20) txi = 1;
if (slot == 1 && state->dmr_soR & 0x20) txi = 1;
// 9.3.2 Pre-emption and power control Indicator (PI)
// 0 - The embedded signalling carries information associated to the same logical channel or the Null embedded message
// 1 - The embedded signalling carries RC information associated to the other logical channel
for(i = 0; i < 32; i++) sbrc_interleaved[i] = state->dmr_embedded_signalling[slot][5][i + 8];
//power == 0 should be single burst
if (power == 0) irr_err = BPTC_16x2_Extract_Data(sbrc_interleaved, sbrc_return, 0);
//power == 1 should be reverse channel -- still need to check the interleave inside of BPTC
if (power == 1) irr_err = BPTC_16x2_Extract_Data(sbrc_interleaved, sbrc_return, 1);
//bad emb burst, never set a valid power indicator value (probably 9)
if (power > 1) goto SBRC_END;
//arrange the return for proper order for the crc3 check
for (i = 0; i < 8; i++) sbrc_retcrc[i] = sbrc_return[i+3];
//RC Channel CRC 7 Mask = 0x7A; CRC bits are used as privacy indicators on
//Single Voice Burst F (see below), other moto values seem to exist there as well -- See TXI patent
if (power == 1) //RC
{
crc_extracted = 0;
for (i = 0; i < 7; i++)
{
crc_extracted = crc_extracted << 1;
crc_extracted = crc_extracted | sbrc_return[i+4];
}
crc_extracted = crc_extracted ^ 0x7A;
crc_computed = crc7((uint8_t *) sbrc_return, 7);
if (crc_extracted == crc_computed) crc7_okay = 1;
}
else //if (txi == 1) //if TXI -- but TXI systems also carry the non-crc protected ENC identifiers
{
crc_extracted = 0;
for (i = 0; i < 3; i++)
{
crc_extracted = crc_extracted << 1;
crc_extracted = crc_extracted | sbrc_return[i]; //first 3 most significant bits
}
crc_computed = crc3((uint8_t *) sbrc_retcrc, 8); //working now seems consistent as well
if (crc_extracted == crc_computed) crc3_okay = 1;
// fprintf (stderr, " CRC EXT %02X, CRC CMP %02X", crc_extracted, crc_computed);
}
// else //crc_okay = 0; //CRC invalid / not available when is ENC Identifiers (I really hate that)
for(i = 0; i < 11; i++)
{
sbrc_hex = sbrc_hex << 1;
sbrc_hex |= sbrc_return[i] & 1;
}
if (opts->payload == 1) //hide the sb/rc behind the payload printer, won't be useful to most people
{
fprintf (stderr, "%s", KCYN);
if (power == 0) fprintf (stderr, " SB: ");
if (power == 1) fprintf (stderr, " RC: ");
for(i = 0; i < 11; i++)
fprintf (stderr, "%d", sbrc_return[i]);
fprintf (stderr, " - %03X; ", sbrc_hex);
fprintf (stderr, "%s", KNRM);
// if (crc_okay == 0) //forego this since the crc can vary or not be used at all
// {
// fprintf (stderr, "%s", KRED);
// fprintf (stderr, " (CRC ERR)");
// fprintf (stderr, "%s", KNRM);
// fprintf (stderr, " CRC EXT %02X, CRC CMP %02X", crc_extracted, crc_computed);
// }
fprintf (stderr, "\n");
}
uint8_t sbrc_opcode = sbrc_hex & 0x7; //opcode and alg the same bits, but the alg is present when CRC is bad (I know they are limited on bits, but I hate that idea)
uint8_t alg = sbrc_hex & 0x7;
uint8_t key = (sbrc_hex >> 3) & 0xFF;
uint8_t txi_delay = (sbrc_hex >> 3) & 0x1F; //middle five are the 'delay' value on a TXI system
//Note: AES-256 Key 1 will pass a CRC3 due to its bit arrangement vs the CRC poly 1101
// if (irr_err == 0 && sbrc_hex = 0xD) crc3_okay = 0; //SB: 00000001101
//NOTE: on above, I belive that we need to check by opcode as well, as a CRC3 can have multiple collisions
//so we need to exclude op/alg 0 and 3 from the check (does algID 0x03/0x23 even exist?)
if (opts->dmr_le == 1) //this will now require a user to switch it on or off until more testing/figuring can be done
{
if (irr_err != 0) fprintf (stderr, "\n%s SLOT %d SB/RC (FEC ERR) %d %s \n", KRED, slot, irr_err, KNRM);
if (irr_err == 0)
{
if (sbrc_hex == 0) ; //NULL, do nothing
//else if (placeholder for future conditions)
// {
// placeholder for future conditions
// }
else if (crc7_okay == 1)
{
//do something with the reverse channel information
}
//if the call is interruptable (TXI) and the crc3 is okay and TXI Opcode
else if (crc3_okay == 1 && (sbrc_opcode == 0 || sbrc_opcode == 3) )
{
//opcodes -- 0 (NULL), BR Delay (3)
fprintf (stderr, "\n");
fprintf (stderr, " TXI Op: %X - ", sbrc_opcode);
if (sbrc_opcode == 0) fprintf (stderr, " Null; ");
else if (sbrc_opcode == 3)
{
if (txi_delay != 0)
fprintf (stderr, " BR Delay: %d - %d ms; ", txi_delay, txi_delay * 30); //could also indicate number of superframes until next VC6 pre-emption
else fprintf (stderr, "BR Delay: Irrelevant / Send at any time;");
}
else fprintf (stderr, " Unk; ");
if (opts->payload == 1) fprintf (stderr, "\n"); //only during payload
}
else if (sbrc_opcode != 0 || sbrc_opcode != 3) //all that should be left in this field is the potential ENC identifiers
{
if (slot == 0) //may not need the state->errs anymore //&& state->errs < 3
{
if (state->dmr_so & 0x40 && key != 0 && state->payload_keyid == 0)
{
//if we aren't forcing a particular alg or privacy key set
if (state->M == 0)
{
fprintf (stderr, "\n");
fprintf (stderr, "%s ", KYEL);
fprintf (stderr, " Slot 1");
fprintf (stderr, " DMR LE SB ALG ID: %X KEY ID: %0X", alg + 0x20, key);
// fprintf (stderr, "\n");
fprintf (stderr, "%s ", KNRM);
state->payload_keyid = key;
state->payload_algid = alg + 0x20; //assuming DMRA approved alg values (moto patent)
}
}
}
if (slot == 1) //may not need the state->errs anymore //&& state->errsR < 3
{
if (state->dmr_soR & 0x40 && key != 0 && state->payload_keyidR == 0)
{
//if we aren't forcing a particular alg or privacy key set
if (state->M == 0)
{
fprintf (stderr, "\n");
fprintf (stderr, "%s ", KYEL);
fprintf (stderr, " Slot 2");
fprintf (stderr, " DMR LE SB ALG ID: %X KEY ID: %0X", alg + 0x20, key);
// fprintf (stderr, "\n");
fprintf (stderr, "%s ", KNRM);
state->payload_keyidR = key;
state->payload_algidR = alg + 0x20; //assuming DMRA approved alg values (moto patent)
}
}
}
}
}
}
SBRC_END:
//'DSP' output to file -- only RC, or RC and SB?
if (power == 1 && opts->use_dsp_output == 1 && sbrc_hex != 0) //if not NULL
{
FILE * pFile; //file pointer
pFile = fopen (opts->dsp_out_file, "a");
fprintf (pFile, "\n%d 99 ", slot+1); //'99' is RC designation value
int k = 0;
for (i = 0; i < 24; i++) //12 bytes, SB or RC
{
//check to see if k++ starts at zero, or at 1
int sbrc_nib = (state->dmr_embedded_signalling[slot][5][k++] << 3) | (state->dmr_embedded_signalling[slot][5][k++] << 2) | (state->dmr_embedded_signalling[slot][5][k++] << 1) | (state->dmr_embedded_signalling[slot][5][k++] << 0);
fprintf (pFile, "%X", sbrc_nib);
}
fclose (pFile);
}
}
uint8_t crc3(uint8_t bits[], unsigned int len)
{
uint8_t crc=0;
unsigned int K = 3;
//x^3+x+1
uint8_t poly[4] = {1,1,0,1};
uint8_t buf[256];
if (len+K > sizeof(buf)) {
return 0;
}
memset (buf, 0, sizeof(buf));
for (unsigned int i=0; i<len; i++){
buf[i] = bits[i];
}
for (unsigned int i=0; i<len; i++)
if (buf[i])
for (unsigned int j=0; j<K+1; j++)
buf[i+j] ^= poly[j];
for (unsigned int i=0; i<K; i++){
crc = (crc << 1) + buf[len + i];
}
return crc;
}
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