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DMR - SB TXI Information and ENC Identifiers Fix;

This commit is contained in:
lwvmobile 2023-06-18 19:54:18 -04:00
parent 56b0e8440e
commit a5d73f06d2
3 changed files with 135 additions and 32 deletions
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2
include/dsd.h
View File

@ -1013,7 +1013,9 @@ void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power);
bool Hamming17123(uint8_t* d);
uint8_t crc8(uint8_t bits[], unsigned int len);
bool crc8_ok(uint8_t bits[], unsigned int len);
//modified CRC functions for SB/RC
uint8_t crc7(uint8_t bits[], unsigned int len);
uint8_t crc3(uint8_t bits[], unsigned int len);
//LFSR and LFSRP code courtesy of https://github.com/mattames/LFSR/
void LFSR(dsd_state * state);

27
src/dmr_flco.c
View File

@ -433,6 +433,8 @@ void dmr_flco (dsd_opts * opts, dsd_state * state, uint8_t lc_bits[], uint32_t C
}
else
{
//Observation: If RS3 is set, or just the bit at location 0001 0000,
//then the NEXT VC6 will be pre-empted for TXI
//REMUS! Uncomment Line Below if desired
// strcat (state->call_string[slot], " RES");
fprintf(stderr, "RS%d ", (so & 0x30) >> 4);
@ -512,14 +514,35 @@ void dmr_flco (dsd_opts * opts, dsd_state * state, uint8_t lc_bits[], uint32_t C
}
}
if (state->K != 0 && fid == 0x10 && so & 0x40)
//BUGFIX: Include slot and algid so we don't accidentally print more than one loaded key
//this can happen on Missing PI header and LE when the keyloader has loaded a TG/Hash key and an RC4 key simultandeously
//subsequennt EMB would print two key values until call cleared out
if (state->K != 0 && fid == 0x10 && so & 0x40 && slot == 0 && state->payload_algid == 0)
{
fprintf (stderr, "%s", KYEL);
fprintf (stderr, "Key %lld ", state->K);
fprintf (stderr, "%s ", KNRM);
}
if (state->K1 != 0 && fid == 0x68 && so & 0x40)
if (state->K != 0 && fid == 0x10 && so & 0x40 && slot == 1 && state->payload_algidR == 0)
{
fprintf (stderr, "%s", KYEL);
fprintf (stderr, "Key %lld ", state->K);
fprintf (stderr, "%s ", KNRM);
}
if (state->K1 != 0 && fid == 0x68 && so & 0x40 && slot == 0 && state->payload_algid == 0)
{
if (state->K2 != 0) fprintf (stderr, "\n ");
fprintf (stderr, "%s", KYEL);
fprintf (stderr, "Key %010llX ", state->K1);
if (state->K2 != 0) fprintf (stderr, "%016llX ", state->K2);
if (state->K4 != 0) fprintf (stderr, "%016llX %016llX", state->K3, state->K4);
fprintf (stderr, "%s ", KNRM);
}
if (state->K1 != 0 && fid == 0x68 && so & 0x40 && slot == 1 && state->payload_algidR == 0)
{
if (state->K2 != 0) fprintf (stderr, "\n ");
fprintf (stderr, "%s", KYEL);

136
src/dmr_le.c
View File

@ -178,13 +178,24 @@ void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power)
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 crc_okay = 0;
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
@ -198,8 +209,11 @@ void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power)
//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
//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;
@ -209,15 +223,27 @@ void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power)
crc_extracted = crc_extracted | sbrc_return[i+4];
}
crc_extracted = crc_extracted ^ 0x7A;
crc_computed = crc7((uint8_t *) sbrc_return, 11);
if (crc_extracted == crc_computed) crc_okay = 1;
crc_computed = crc7((uint8_t *) sbrc_return, 7);
if (crc_extracted == crc_computed) crc7_okay = 1;
}
else crc_okay = 1; //SB
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; //sbrc_return
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
@ -227,48 +253,76 @@ void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power)
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, " - %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");
fprintf (stderr, "%s", KNRM);
if (crc_okay == 0)
{
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
fprintf (stderr, " CRC EXT %02X, CRC CMP %02X", crc_extracted, crc_computed);
}
}
uint8_t sbrc_opcode = sbrc_hex;
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 cap_site = (sbrc_hex >> 4) & 0x7; //signalling on Cap+ when voice errors (non voice VC6 is present)
uint8_t txi_delay = (sbrc_hex >> 3) & 0x1F; //middle five are the 'delay' value on a TXI system
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) 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
if (sbrc_hex == 0) ; //NULL, do nothing
//else if (placeholder for future conditions)
// {
// placeholder for future conditions
// }
else //Finally have a consistent set-up for this -- spoke too soon, sadly
else if (crc7_okay == 1)
{
//the signalling here is always presents on good voice frames, if errs are [3][2] then its not a VC6 voice frame, but some other 'hidden' frame
if (slot == 0 && state->errs < 3)
//do something with the reverse channel information
}
//if the call is interruptable (TXI) and the crc3 is okay
else if (crc3_okay == 1)
{
//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 //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, "\n");
fprintf (stderr, "%s ", KNRM);
state->payload_keyid = key;
@ -278,18 +332,18 @@ void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power)
}
}
//the signalling here is always presents on good voice frames, if errs are [3][2] then its not a VC6 voice frame, but some other 'hidden' frame
if (slot == 1 && state->errsR < 3)
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, "%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 ", 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;
@ -324,3 +378,27 @@ void dmr_sbrc (dsd_opts * opts, dsd_state * state, uint8_t power)
}
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;
}