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DMR: Tidy Up PDU Enc Code;

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lwvmobile
2025-03-03 23:09:02 -05:00
parent 4255a2f9ba
commit eebb251d2f
1 changed files with 12 additions and 19 deletions
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31
src/dmr_block.c
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@@ -890,12 +890,12 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
#ifdef DMR_PDU_DECRYPTION #ifdef DMR_PDU_DECRYPTION
if (enc_check) if (enc_check)
{ {
// decrypted_pdu = 0; //hasn't been decrypted yet
int poc = (int)state->data_block_poc[slot]; //say that three times real fast int poc = (int)state->data_block_poc[slot];
int start = (int)state->data_ks_start[slot]; int start = (int)state->data_ks_start[slot];
int end = ((blocks+1)*block_len)-4-poc-start; int end = ((blocks+1)*block_len)-4-poc-start;
//sanity check on end, has to be a positive value //sanity check on end, has to be a positive value
if (end < 0) end = 3096; //its a signed interger, so should reflect negative values here and not rollover if (end < 0) end = 3096;
int alg = 0; int alg = 0;
int kid = 0; int kid = 0;
if (state->currentslot == 0) if (state->currentslot == 0)
@@ -907,21 +907,20 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
else kid = state->payload_keyidR; else kid = state->payload_keyidR;
//start keystream creation //start keystream creation
uint8_t ob[129*24]; //may need more blocks (enough for 127 * 24) uint8_t ob[129*24];
uint8_t kiv[9]; UNUSED(kiv); uint8_t kiv[9];
uint32_t mi = 0; uint32_t mi = 0;
unsigned long long int R = 0; unsigned long long int R = 0;
if (state->currentslot == 0) if (state->currentslot == 0)
mi = (uint32_t)state->payload_mi; mi = (uint32_t)state->payload_mi;
else mi = (uint32_t)state->payload_miR; else mi = (uint32_t)state->payload_miR;
//mini key loader for RC4/DES //key loader
if (state->currentslot == 0) if (state->currentslot == 0)
R = state->rkey_array[state->payload_keyid]; R = state->rkey_array[state->payload_keyid];
else else
R = state->rkey_array[state->payload_keyidR]; R = state->rkey_array[state->payload_keyidR];
if (R == 0 && state->R != 0) R = state->R; if (R == 0 && state->R != 0) R = state->R;
//easier to manually load up rather than make a loop (RC4) //easier to manually load up rather than make a loop (RC4)
@@ -953,18 +952,15 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
//NOTE: Observed that keystream should not be applied to pad bytes or CRC //NOTE: Observed that keystream should not be applied to pad bytes or CRC
//apply keystream here, only if alg is 1 or 4 AND key is available! //apply keystream here, only if alg is 1 or 4 AND key is available!
//using modulus 3096 to prevent sefgault (increased storage and changed ofb modes to a ptr)
//will want to rework output_blocks to be a pointer instead of a fixed size (done)
if (alg == 1 && R != 0) if (alg == 1 && R != 0)
{ {
for (i = 0; i < end; i++) for (i = 0; i < end; i++)
state->dmr_pdu_sf[slot][i+start] ^= ob[i%3096]; state->dmr_pdu_sf[slot][i+start] ^= ob[i%3096];
} }
//BP key application
else if (alg == 0) //&& state->K != 0
{
//NOTE: using dmr_sr and dmr_soR now for a enc check on all encrypted PDUs //BP key application
else if (alg == 0)
{
uint16_t bp_key = 0; uint16_t bp_key = 0;
if (state->K != 0) //state->M == 1 && if (state->K != 0) //state->M == 1 &&
{ {
@@ -972,22 +968,19 @@ void dmr_block_assembler (dsd_opts * opts, dsd_state * state, uint8_t block_byte
bp_key = BPK[state->K]; bp_key = BPK[state->K];
ob[0] = (bp_key >> 8) & 0xFF; ob[0] = (bp_key >> 8) & 0xFF;
ob[1] = (bp_key >> 0) & 0xFF; ob[1] = (bp_key >> 0) & 0xFF;
fprintf (stderr, " Key: %lld : %04X;", state->K, bp_key);
//
fprintf (stderr, " Key: %lld:%04X;", state->K, bp_key);
// fprintf (stderr, "ob1: %02X; ob2: %02X", ob[0], ob[1]);
} }
if (bp_key != 0) if (bp_key != 0)
{ {
for (i = start; i < (end-start); i++) for (i = start; i < (end-start); i++)
state->dmr_pdu_sf[slot][i] ^= ob[i%2]; //modulus 2 here, just rinse and repeat state->dmr_pdu_sf[slot][i] ^= ob[i%2];
decrypted_pdu = 1; decrypted_pdu = 1;
} }
} }
//reset alg/keyid/mi after running? //reset alg/keyid/mi
if (state->currentslot == 0) if (state->currentslot == 0)
{ {
state->payload_mi = 0; state->payload_mi = 0;