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dsd-fme/src/nxdn_deperm.c
lwvmobile 00e0f00974 NXDN Tweaks to clear stale key values on keyload;
2023-04-29 17:02:55 -04:00

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//NXDN descramble/deperm/depuncture and crc/utility functions
//Reworked portions from Osmocom OP25
/* -*- c++ -*- */
/*
* NXDN Encoder/Decoder (C) Copyright 2019 Max H. Parke KA1RBI
*
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "dsd.h"
#include "nxdn_const.h"
static const uint8_t scramble_t[] = { //values are the position values we need to invert in the descramble
2, 5, 6, 7, 10, 12, 14, 16, 17, 22, 23, 25, 26, 27, 28, 30, 33, 34, 36, 37, 38, 41, 45, 47,
52, 54, 56, 57, 59, 62, 63, 64, 65, 66, 67, 69, 70, 73, 76, 79, 81, 82, 84, 85, 86, 87, 88,
89, 92, 95, 96, 98, 100, 103, 104, 107, 108, 116, 117, 121, 122, 125, 127, 131, 132, 134,
137, 139, 140, 141, 142, 143, 144, 145, 147, 151, 153, 154, 158, 159, 160, 162, 164, 165,
168, 170, 171, 174, 175, 176, 177, 181
};
static const int PARITY[] = {
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0,
1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1,
1, 0, 0, 1, 1, 0, 1, 0, 0, 1
};
//decoding functions here
void nxdn_descramble(uint8_t dibits[], int len)
{
for (int i=0; i<len; i++)
{
if (scramble_t[i] >= len)
break;
dibits[scramble_t[i]] ^= 0x2; // invert sign of scrambled dibits
}
}
void nxdn_deperm_facch(dsd_opts * opts, dsd_state * state, uint8_t bits[144])
{
uint8_t deperm[200]; //144
uint8_t depunc[200]; //192
uint8_t trellis_buf[400]; //96
uint16_t crc = 0; //crc calculated by function
uint16_t check = 0; //crc from payload for comparison
int out;
memset (deperm, 0, sizeof(deperm));
memset (depunc, 0, sizeof(depunc));
for (int i=0; i<144; i++)
deperm[PERM_16_9[i]] = bits[i];
out = 0;
for (int i=0; i<144; i+=3) {
depunc[out++] = deperm[i+0];
depunc[out++] = 0;
depunc[out++] = deperm[i+1];
depunc[out++] = deperm[i+2];
}
//switch to the convolutional decoder
uint8_t temp[210];
uint8_t s0;
uint8_t s1;
uint8_t m_data[20]; //13
memset (temp, 0, sizeof(temp));
memset (m_data, 0, sizeof(m_data));
memset (trellis_buf, 0, sizeof(trellis_buf));
for (int i = 0; i < 192; i++)
{
temp[i] = depunc[i] << 1;
}
for (int i = 0; i < 8; i++)
{
temp[i+192] = 0;
}
CNXDNConvolution_start();
for (int i = 0U; i < 100U; i++)
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
CNXDNConvolution_chainback(m_data, 96U);
for(int i = 0; i < 12; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
crc = crc12f (trellis_buf, 84); //80
for (int i = 0; i < 12; i++)
{
check = check << 1;
check = check | trellis_buf[84+i]; //80
}
if (crc != check)
{
fprintf (stderr, " FACCH");
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
if (crc == check) NXDN_Elements_Content_decode(opts, state, 1, trellis_buf);
else if (opts->aggressive_framesync == 0) NXDN_Elements_Content_decode(opts, state, 0, trellis_buf);
if (opts->payload == 1)
{
fprintf (stderr, "\n");
fprintf (stderr, " FACCH Payload ");
for (int i = 0; i < 12; i++)
{
fprintf (stderr, "[%02X]", m_data[i]);
}
// fprintf (stderr, " - %03X %03X", check, crc);
}
}
//sacch
void nxdn_deperm_sacch(dsd_opts * opts, dsd_state * state, uint8_t bits[60])
{
//see about initializing these variables
uint8_t deperm[200]; //60
uint8_t depunc[200]; //72
uint8_t trellis_buf[400]; //32
memset (deperm, 0, sizeof(deperm));
memset (depunc, 0, sizeof(depunc));
memset (trellis_buf, 0, sizeof(trellis_buf));
int o = 0;
uint8_t crc = 0; //value computed by crc6 on payload
uint8_t check = 0; //value pulled from last 6 bits
int sf = 0;
int ran = 0;
int part_of_frame = 0;
for (int i=0; i<60; i++)
deperm[PERM_12_5[i]] = bits[i];
for (int p=0; p<60; p+= 10) {
depunc[o++] = deperm[p+0];
depunc[o++] = deperm[p+1];
depunc[o++] = deperm[p+2];
depunc[o++] = deperm[p+3];
depunc[o++] = deperm[p+4];
depunc[o++] = 0;
depunc[o++] = deperm[p+5];
depunc[o++] = deperm[p+6];
depunc[o++] = deperm[p+7];
depunc[o++] = deperm[p+8];
depunc[o++] = deperm[p+9];
depunc[o++] = 0;
}
//switch to the convolutional decoder
uint8_t temp[90];
uint8_t s0;
uint8_t s1;
uint8_t m_data[10]; //5
memset (temp, 0, sizeof (temp));
memset (m_data, 0, sizeof (m_data));
memset (trellis_buf, 0, sizeof(trellis_buf));
for (int i = 0; i < 72; i++)
{
temp[i] = depunc[i] << 1;
}
for (int i = 0; i < 8; i++)
{
temp[i+72] = 0;
}
CNXDNConvolution_start();
for (int i = 0U; i < 36U; i++) //40
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
//stored as 5 bytes, will need to convert to trellis_buf after running
CNXDNConvolution_chainback(m_data, 32U); //36
for(int i = 0; i < 4; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
crc = crc6(trellis_buf, 26); //32
for (int i = 0; i < 6; i++)
{
check = check << 1;
check = check | trellis_buf[i+26];
}
//FIRST! If part of a non_superframe, and CRC is good, send directly to NXDN_Elements_Content_decode
if (state->nxdn_sacch_non_superframe == TRUE)
{
if (state->nxdn_last_ran != -1) fprintf (stderr, " RAN %02d ", state->nxdn_last_ran);
else fprintf (stderr, " ");
uint8_t nsf_sacch[400];
memset (nsf_sacch, 0, sizeof(nsf_sacch));
for (int i = 0; i < 26; i++)
{
nsf_sacch[i] = trellis_buf[i+8];
}
if (crc == check)
{
ran = (trellis_buf[2] << 5) | (trellis_buf[3] << 4) | (trellis_buf[4] << 3) | (trellis_buf[5] << 2) | (trellis_buf[6] << 1) | trellis_buf[7];
state->nxdn_last_ran = ran;
}
if (crc == check) NXDN_Elements_Content_decode(opts, state, 1, nsf_sacch);
else if (opts->aggressive_framesync == 0) NXDN_Elements_Content_decode(opts, state, 0, nsf_sacch);
if (crc != check)
{
fprintf (stderr, " SACCH NSF");
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
if (opts->payload == 1)
{
fprintf (stderr, "\n SACCH NSF ");
for (int i = 0; i < 4; i++)
{
fprintf (stderr, "[%02X]", m_data[i]);
}
// if (crc != check) fprintf (stderr, " CRC ERR - %02X %02X", check, crc);
}
//reset the sacch field -- Github Issue #118
memset (state->nxdn_sacch_frame_segment, 1, sizeof(state->nxdn_sacch_frame_segment));
memset (state->nxdn_sacch_frame_segcrc, 1, sizeof(state->nxdn_sacch_frame_segcrc));
}
//If part of superframe, collect the fragments and send to NXDN_SACCH_Full_decode instead
else if (state->nxdn_sacch_non_superframe == FALSE)
{
//sf and ran together are denoted as SR in the manual (more confusing acronyms)
//sf (structure field) and RAN will always exist in first 8 bits of each SACCH, then the next 18 bits are the fragment of the superframe
sf = (trellis_buf[0] << 1) | trellis_buf[1];
if (sf == 3) part_of_frame = 0;
else if (sf == 2) part_of_frame = 1;
else if (sf == 1) part_of_frame = 2;
else if (sf == 0) part_of_frame = 3;
else part_of_frame = 0;
fprintf (stderr, "%s", KCYN);
if (state->nxdn_last_ran != -1) fprintf (stderr, " RAN %02d ", state->nxdn_last_ran);
else fprintf (stderr, " ");
fprintf (stderr, "%s", KNRM);
if (crc != check)
{
fprintf (stderr, " SACCH SF%d", sf);
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
//reset scrambler seed to key value on new superframe
if (part_of_frame == 0 && state->nxdn_cipher_type == 0x1) state->payload_miN = 0;
if (crc == check)
{
ran = (trellis_buf[2] << 5) | (trellis_buf[3] << 4) | (trellis_buf[4] << 3) | (trellis_buf[5] << 2) | (trellis_buf[6] << 1) | trellis_buf[7];
state->nxdn_ran = state->nxdn_last_ran = ran;
state->nxdn_sf = sf;
state->nxdn_part_of_frame = part_of_frame;
state->nxdn_sacch_frame_segcrc[part_of_frame] = 0; //zero indicates good check
}
else state->nxdn_sacch_frame_segcrc[part_of_frame] = 1; //1 indicates bad check
int sacch_segment = 0;
for (int i = 0; i < 18; i++)
{
sacch_segment = sacch_segment << 1;
sacch_segment = sacch_segment + trellis_buf[i+8];
state->nxdn_sacch_frame_segment[part_of_frame][i] = trellis_buf[i+8];
}
//Hand off to LEH NXDN_SACCH_Full_decode
if (part_of_frame == 3)
{
NXDN_SACCH_Full_decode (opts, state);
}
if (opts->payload == 1)
{
fprintf (stderr, "\n");
fprintf (stderr, " SACCH SF Segment #%d ", part_of_frame+1);
for (int i = 0; i < 4; i++)
{
fprintf (stderr, "[%02X]", m_data[i]);
}
// if (crc != check) fprintf (stderr, " CRC ERR - %02X %02X", crc, check);
}
}
}
void nxdn_deperm_facch2_udch(dsd_opts * opts, dsd_state * state, uint8_t bits[348], uint8_t type)
{
uint8_t deperm[500]; //348
uint8_t depunc[500]; //406
uint8_t trellis_buf[400]; //199
int id = 0;
uint16_t crc = 0;
uint16_t check = 0;
memset (deperm, 0, sizeof(deperm));
memset (depunc, 0, sizeof(depunc));
for (int i=0; i<348; i++) {
deperm[PERM_12_29[i]] = bits[i];
}
for (int i=0; i<29; i++) {
depunc[id++] = deperm[i*12];
depunc[id++] = deperm[i*12+1];
depunc[id++] = deperm[i*12+2];
depunc[id++] = 0;
depunc[id++] = deperm[i*12+3];
depunc[id++] = deperm[i*12+4];
depunc[id++] = deperm[i*12+5];
depunc[id++] = deperm[i*12+6];
depunc[id++] = deperm[i*12+7];
depunc[id++] = deperm[i*12+8];
depunc[id++] = deperm[i*12+9];
depunc[id++] = 0;
depunc[id++] = deperm[i*12+10];
depunc[id++] = deperm[i*12+11];
}
//switch to the convolutional decoder
uint8_t temp[500]; //220, this one was way too small
uint8_t s0;
uint8_t s1;
uint8_t m_data[52]; //26
memset (trellis_buf, 0, sizeof(trellis_buf));
memset (temp, 0, sizeof (temp));
memset (m_data, 0, sizeof (m_data));
for (int i = 0; i < 406; i++)
{
temp[i] = depunc[i] << 1;
}
for (int i = 0; i < 8; i++)
{
temp[i+203] = 0;
}
CNXDNConvolution_start();
for (int i = 0U; i < 207U; i++)
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
//numerals seem okay now
CNXDNConvolution_chainback(m_data, 203U);
for(int i = 0; i < 26; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
crc = crc15(trellis_buf, 199);
for (int i = 0; i < 15; i++)
{
check = check << 1;
check = check | trellis_buf[i+184];
}
if (crc != check)
{
fprintf (stderr, "%s", KYEL);
if (type == 0) fprintf (stderr, " UDCH");
if (type == 1) fprintf (stderr, " FACCH2");
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
uint8_t f2u_message_buffer[400]; //199
memset (f2u_message_buffer, 0, sizeof(f2u_message_buffer));
//just going to leave this all here in case its needed, like in cac,
//don't have any samples with f2 or udch data in it
for (int i = 0; i < 199-8; i++)
{
f2u_message_buffer[i] = trellis_buf[i+8];
}
if (crc == check)
{
if (type == 1) NXDN_Elements_Content_decode(opts, state, 1, f2u_message_buffer);
if (type == 0) ; //need handling for user data (text messages and AVL)
}
else if (opts->aggressive_framesync == 0)
{
if (type == 1) NXDN_Elements_Content_decode(opts, state, 0, f2u_message_buffer);
if (type == 0) ; //need handling for user data (text messages and AVL)
}
if (opts->payload == 1)
{
fprintf (stderr, "\n");
if (type == 0) fprintf (stderr, " UDCH");
if (type == 1) fprintf (stderr, " FACCH2");
fprintf (stderr, " Payload\n ");
for (int i = 0; i < 26; i++)
{
if (i == 13) fprintf (stderr, "\n ");
fprintf (stderr, "[%02X]", m_data[i]);
}
// if (crc != check) fprintf (stderr, " CRC ERR ");
if (type == 0)
{
fprintf (stderr, "\n UDCH Data: ASCII - " );
for (int i = 0; i < 24; i++) //remove crc portion
{
if (m_data[i] <= 0x7E && m_data[i] >=0x20)
{
fprintf (stderr, "%c", m_data[i]);
}
else fprintf (stderr, " ");
}
}
}
}
void nxdn_deperm_cac(dsd_opts * opts, dsd_state * state, uint8_t bits[300])
{
uint8_t deperm[500]; //300
uint8_t depunc[500]; //350
uint8_t trellis_buf[400]; //171
int id = 0;
int ran = 0;
uint16_t crc = 0;
memset (deperm, 0, sizeof(deperm));
memset (depunc, 0, sizeof(depunc));
for (int i=0; i<300; i++) {
deperm[PERM_12_25[i]] = bits[i];
}
for (int i=0; i<25; i++) {
depunc[id++] = deperm[i*12];
depunc[id++] = deperm[i*12+1];
depunc[id++] = deperm[i*12+2];
depunc[id++] = 0;
depunc[id++] = deperm[i*12+3];
depunc[id++] = deperm[i*12+4];
depunc[id++] = deperm[i*12+5];
depunc[id++] = deperm[i*12+6];
depunc[id++] = deperm[i*12+7];
depunc[id++] = deperm[i*12+8];
depunc[id++] = deperm[i*12+9];
depunc[id++] = 0;
depunc[id++] = deperm[i*12+10];
depunc[id++] = deperm[i*12+11];
}
//switch to the convolutional decoder
uint8_t temp[360];
uint8_t s0;
uint8_t s1;
uint8_t m_data[52]; //26
memset (trellis_buf, 0, sizeof(trellis_buf));
memset (temp, 0, sizeof (temp));
memset (m_data, 0, sizeof (m_data));
for (int i = 0; i < 350; i++)
{
temp[i] = depunc[i] << 1;
}
CNXDNConvolution_start();
for (int i = 0U; i < 179U; i++)
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
CNXDNConvolution_chainback(m_data, 175U);
for(int i = 0; i < 22; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
crc = crc16cac(trellis_buf, 171);
uint8_t cac_message_buffer[400]; //171
memset (cac_message_buffer, 0, sizeof(cac_message_buffer));
//shift the cac_message into the appropriate byte arrangement for element_decoder -- skip SR field
for (int i = 0; i < 160; i++)
{
cac_message_buffer[i] = trellis_buf[i+8];
}
if (state->nxdn_last_ran != -1) fprintf (stderr, " RAN %02d ", state->nxdn_last_ran);
else fprintf (stderr, " ");
if (crc == 0)
{
ran = (trellis_buf[2] << 5) | (trellis_buf[3] << 4) | (trellis_buf[4] << 3) | (trellis_buf[5] << 2) | (trellis_buf[6] << 1) | trellis_buf[7];
state->nxdn_last_ran = ran;
}
fprintf (stderr, "%s", KYEL);
fprintf (stderr, " CAC");
fprintf (stderr, "%s", KNRM);
if (crc != 0)
{
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
if (crc == 0) NXDN_Elements_Content_decode(opts, state, 1, cac_message_buffer);
else if (opts->aggressive_framesync == 0) NXDN_Elements_Content_decode(opts, state, 0, cac_message_buffer);
if (opts->payload == 1)
{
fprintf (stderr, "\n");
fprintf (stderr, " CAC Payload\n ");
for (int i = 0; i < 22; i++)
{
fprintf (stderr, "[%02X]", m_data[i]);
if (i == 10) fprintf (stderr, "\n ");
}
// if (crc != 0) fprintf (stderr, " CRC ERR ");
}
}
//Type-D "IDAS"
void nxdn_deperm_scch(dsd_opts * opts, dsd_state * state, uint8_t bits[60], uint8_t direction)
{
fprintf (stderr, "%s", KYEL);
fprintf (stderr, " SCCH");
//see about initializing these variables
uint8_t deperm[200]; //60
uint8_t depunc[200]; //72
uint8_t trellis_buf[400]; //32
memset (deperm, 0, sizeof(deperm));
memset (depunc, 0, sizeof(depunc));
memset (trellis_buf, 0, sizeof(trellis_buf));
int o = 0;
uint8_t crc = 0; //value computed by crc7 on payload
uint8_t check = 0; //value pulled from last 7 bits
int sf = 0;
int part_of_frame = 0;
for (int i=0; i<60; i++)
deperm[PERM_12_5[i]] = bits[i];
for (int p=0; p<60; p+= 10) {
depunc[o++] = deperm[p+0];
depunc[o++] = deperm[p+1];
depunc[o++] = deperm[p+2];
depunc[o++] = deperm[p+3];
depunc[o++] = deperm[p+4];
depunc[o++] = 0;
depunc[o++] = deperm[p+5];
depunc[o++] = deperm[p+6];
depunc[o++] = deperm[p+7];
depunc[o++] = deperm[p+8];
depunc[o++] = deperm[p+9];
depunc[o++] = 0;
}
//switch to the convolutional decoder
uint8_t temp[90];
uint8_t s0;
uint8_t s1;
uint8_t m_data[10]; //5
memset (temp, 0, sizeof (temp));
memset (m_data, 0, sizeof (m_data));
memset (trellis_buf, 0, sizeof(trellis_buf));
for (int i = 0; i < 72; i++)
{
temp[i] = depunc[i] << 1;
}
for (int i = 0; i < 8; i++)
{
temp[i+72] = 0;
}
CNXDNConvolution_start();
for (int i = 0U; i < 36U; i++)
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
CNXDNConvolution_chainback(m_data, 32U);
for(int i = 0; i < 4; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
crc = crc7_scch(trellis_buf, 25);
for (int i = 0; i < 7; i++)
{
check = check << 1;
check = check | trellis_buf[i+25];
}
//check the sf early for scrambler reset, if required
sf = (trellis_buf[0] << 1) | trellis_buf[1];
if (sf == 3) part_of_frame = 0;
else if (sf == 2) part_of_frame = 1;
else if (sf == 1) part_of_frame = 2;
else if (sf == 0) part_of_frame = 3;
else part_of_frame = 0;
//reset scrambler seed to key value on new superframe
if (part_of_frame == 0 && state->nxdn_cipher_type == 0x1) state->payload_miN = 0;
/*
4.3.2. Mapping to Functional Channel
When Subscriber Unit performs voice communication in RTCH2, SCCH is allocated as
described below.
SCCH has super Frame Structure with 4 frame unit during communication, and has non
super Frame Structure with single frame unit at the start time and end time of sending.
Allocation of the other channel is not specified particularly.
*/
//English Translation: Superframe when voice, Non Superframe when not voice
//What I've found is that by not using the superframe structure, and decoding each 'unit'
//individually instead, we can get more expedient decoding on elements without having to
//sacrifice an entire superframe for one bad CRC, also each element cleanly divides into a
//single 'unit' except for enc parms IV, which can be stored seperately if needed
//NOTE: scch has its own message format, and thus, doesn't go to content element decoding
//like everything else does
if (crc != check)
{
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
if (crc == check) NXDN_decode_scch (opts, state, trellis_buf, direction);
else if (opts->aggressive_framesync == 0) NXDN_decode_scch (opts, state, trellis_buf, direction);
fprintf (stderr, "%s", KNRM);
if (opts->payload == 1)
{
fprintf (stderr, "\n SCCH Payload ");
for (int i = 0; i < 4; i++)
{
fprintf (stderr, "[%02X]", m_data[i]);
}
// if (crc != check) fprintf (stderr, " CRC ERR - %02X %02X", check, crc);
}
fprintf (stderr, "%s", KNRM);
}
void nxdn_deperm_facch3_udch2(dsd_opts * opts, dsd_state * state, uint8_t bits[288], uint8_t type)
{
uint8_t deperm[300]; //144
uint8_t depunc[300]; //192
uint8_t trellis_buf[600]; //96
uint8_t f3_udch2[288]; //completed bitstream without crc and tailing bits attached
uint8_t f3_udch2_bytes[36]; //completed bytes - with crc and tail
uint16_t crc[2]; //crc calculated by function
uint16_t check[2]; //crc from payload for comparison
int out;
//switch to the convolutional decoder
uint8_t temp[500];
uint8_t s0;
uint8_t s1;
uint8_t m_data[40]; //13
memset (temp, 0, sizeof(temp));
memset (m_data, 0, sizeof(m_data));
memset (trellis_buf, 0, sizeof(trellis_buf));
memset (deperm, 0, sizeof(deperm));
memset (depunc, 0, sizeof(depunc));
memset (crc, 0, sizeof(crc));
memset (check, 0, sizeof(check));
memset (f3_udch2, 0, sizeof(f3_udch2));
memset (f3_udch2_bytes, 0, sizeof(f3_udch2_bytes));
for (int j=0; j<2; j++)
{
for (int i=0; i<144; i++)
deperm[PERM_16_9[i]] = bits[i+(j*144)];
out = 0;
for (int i=0; i<144; i+=3) {
depunc[out++] = deperm[i+0];
depunc[out++] = 0;
depunc[out++] = deperm[i+1];
depunc[out++] = deperm[i+2];
}
for (int i = 0; i < 192; i++)
{
temp[i] = depunc[i] << 1;
}
for (int i = 0; i < 8; i++)
{
temp[i+192] = 0;
}
CNXDNConvolution_start();
for (int i = 0U; i < 100U; i++)
{
s0 = temp[(2*i)];
s1 = temp[(2*i)+1];
CNXDNConvolution_decode(s0, s1);
}
CNXDNConvolution_chainback(m_data, 96U);
for(int i = 0; i < 12; i++)
{
trellis_buf[(i*8)+0] = (m_data[i] >> 7) & 1;
trellis_buf[(i*8)+1] = (m_data[i] >> 6) & 1;
trellis_buf[(i*8)+2] = (m_data[i] >> 5) & 1;
trellis_buf[(i*8)+3] = (m_data[i] >> 4) & 1;
trellis_buf[(i*8)+4] = (m_data[i] >> 3) & 1;
trellis_buf[(i*8)+5] = (m_data[i] >> 2) & 1;
trellis_buf[(i*8)+6] = (m_data[i] >> 1) & 1;
trellis_buf[(i*8)+7] = (m_data[i] >> 0) & 1;
}
crc[j] = crc12f (trellis_buf, 84); //84
for (int i = 0; i < 12; i++)
{
check[j] = check[j] << 1;
check[j] = check[j] | trellis_buf[84+i]; //84
}
//transfer to storage sans crc and tail bits
for (int i = 0; i < 80; i++) f3_udch2[i+(j*80)] = trellis_buf[i];
for (int i = 0; i < 12; i++) f3_udch2_bytes[i+(j*12)] = m_data[i];
}
if (crc[0] != check[0] || crc[1] != check[1])
{
if (type == 0) fprintf (stderr, " UDCH2");
if (type == 1) fprintf (stderr, " FACCH3");
fprintf (stderr, "%s", KRED);
fprintf (stderr, " (CRC ERR)");
fprintf (stderr, "%s", KNRM);
}
if (crc[0] == check[0] && crc[1] == check[1])
{
if (type == 1) NXDN_Elements_Content_decode(opts, state, 1, trellis_buf);
if (type == 0) ; //need handling for user data (text messages and AVL)
}
else if (opts->aggressive_framesync == 0)
{
if (type == 1) NXDN_Elements_Content_decode(opts, state, 0, trellis_buf);
if (type == 0) ; //need handling for user data (text messages and AVL)
}
if (opts->payload == 1)
{
fprintf (stderr, "\n");
if (type == 0) fprintf (stderr, " UDCH2");
if (type == 1) fprintf (stderr, " FACCH3");
fprintf (stderr, " Payload \n ");
for (int i = 0; i < 24; i++)
{
if (i == 12) fprintf (stderr, "\n ");
fprintf (stderr, "[%02X]", f3_udch2_bytes[i]);
}
// fprintf (stderr, " - %03X %03X", check[0], crc[0]);
// fprintf (stderr, " - %03X %03X", check[1], crc[1]);
if (type == 0)
{
fprintf (stderr, "\n UDCH2 Data: ASCII - " );
for (int i = 0; i < 22; i++) //all but last crc portion
{
if (i == 12) i = 14; //skip first crc portion
if (f3_udch2_bytes[i] <= 0x7E && f3_udch2_bytes[i] >=0x20)
{
fprintf (stderr, "%c", f3_udch2_bytes[i]);
}
else fprintf (stderr, " ");
}
}
}
}
void nxdn_message_type (dsd_opts * opts, dsd_state * state, uint8_t MessageType)
{
//NOTE: Most Req/Resp (request and respone) share same message type but differ depending on channel type
//RTCH Outbound will take precedent when differences may occur (except CALL_ASSGN)
fprintf (stderr, "%s", KYEL);
if (MessageType == 0x10) fprintf(stderr, " IDLE");
else if (MessageType == 0x00) fprintf(stderr, " CALL_RESP");
else if (MessageType == 0x01) fprintf(stderr, " VCALL");
else if (MessageType == 0x02) fprintf(stderr, " VCALL_REC_REQ");
else if (MessageType == 0x03) fprintf(stderr, " VCALL_IV");
else if (MessageType == 0x04) fprintf(stderr, " VCALL_ASSGN");
else if (MessageType == 0x05) fprintf(stderr, " VCALL_ASSGN_DUP");
else if (MessageType == 0x06) fprintf(stderr, " CALL_CONN_RESP");
else if (MessageType == 0x07) fprintf(stderr, " TX_REL_EX");
else if (MessageType == 0x08) fprintf(stderr, " TX_REL");
else if (MessageType == 0x09) fprintf(stderr, " DCALL_HEADER");
else if (MessageType == 0x0A) fprintf(stderr, " DCALL_REC_REQ");
else if (MessageType == 0x0B) fprintf(stderr, " DCALL_UDATA");
else if (MessageType == 0x0C) fprintf(stderr, " DCALL_ACK");
else if (MessageType == 0x0D) fprintf(stderr, " DCALL_ASSGN_DUP");
else if (MessageType == 0x0E) fprintf(stderr, " DCALL_ASSGN");
else if (MessageType == 0x11) fprintf(stderr, " DISC");
else if (MessageType == 0x17) fprintf(stderr, " DST_ID_INFO");
else if (MessageType == 0x18) fprintf(stderr, " SITE_INFO");
else if (MessageType == 0x19) fprintf(stderr, " SRV_INFO");
else if (MessageType == 0x1A) fprintf(stderr, " CCH_INFO");
else if (MessageType == 0x1B) fprintf(stderr, " ADJ_SITE_INFO");
else if (MessageType == 0x1C) fprintf(stderr, " FAIL_STAT_INFO");
else if (MessageType == 0x20) fprintf(stderr, " REG_RESP");
else if (MessageType == 0x22) fprintf(stderr, " REG_C_RESP");
else if (MessageType == 0x24) fprintf(stderr, " GRP_REG_RESP");
else if (MessageType == 0x32) fprintf(stderr, " STAT_REQ");
else if (MessageType == 0x33) fprintf(stderr, " STAT_RESP");
else if (MessageType == 0x38) fprintf(stderr, " SDCALL_REQ_HEADER");
else if (MessageType == 0x39) fprintf(stderr, " SDCALL_REQ_USERDATA");
else if (MessageType == 0x3B) fprintf(stderr, " SDCALL_RESP");
else if (MessageType == 0x3F) fprintf(stderr, " ALIAS");
else fprintf(stderr, " Unknown M-%02X", MessageType);
fprintf (stderr, "%s", KNRM);
//Zero out stale values on DISC or TX_REL only (IDLE messaages occur often on NXDN96 VCH, and randomly on Type-C FACCH1 steals for some reason)
if (MessageType == 0x08 || MessageType == 0x11)
{
memset (state->nxdn_alias_block_segment, 0, sizeof(state->nxdn_alias_block_segment));
state->nxdn_last_rid = 0;
state->nxdn_last_tg = 0;
state->nxdn_cipher_type = 0; //force will reactivate it if needed during voice tx
if (state->keyloader == 1) state->R = 0;
memset (state->nxdn_sacch_frame_segcrc, 1, sizeof(state->nxdn_sacch_frame_segcrc));
memset (state->nxdn_sacch_frame_segment, 1, sizeof(state->nxdn_sacch_frame_segment));
sprintf (state->nxdn_call_type, "%s", "");
}
}
//voice descrambler
void LFSRN(char * BufferIn, char * BufferOut, dsd_state * state)
{
int i;
int lfsr;
int pN[49] = {0};
int bit = 0;
lfsr = state->payload_miN & 0x7FFF;
for (i = 0; i < 49; i++)
{
pN[i] = lfsr & 0x1;
bit = ( (lfsr >> 1) ^ (lfsr >> 0) ) & 1;
lfsr = ( (lfsr >> 1 ) | (bit << 14) );
BufferOut[i] = BufferIn[i] ^ pN[i];
}
state->payload_miN = lfsr & 0x7FFF;
}
static inline int load_i(const uint8_t val[], int len) {
int acc = 0;
for (int i=0; i<len; i++){
acc = (acc << 1) + (val[i] & 1);
}
return acc;
}
static uint8_t crc6(const uint8_t buf[], int len)
{
uint8_t s[6];
uint8_t a;
for (int i=0;i<6;i++)
s[i] = 1;
for (int i=0;i<len;i++) {
a = buf[i] ^ s[0];
s[0] = a ^ s[1];
s[1] = s[2];
s[2] = s[3];
s[3] = a ^ s[4];
s[4] = a ^ s[5];
s[5] = a;
}
return load_i(s, 6);
}
static uint16_t crc12f(const uint8_t buf[], int len)
{
uint8_t s[12];
uint8_t a;
for (int i=0;i<12;i++)
s[i] = 1;
for (int i=0;i<len;i++) {
a = buf[i] ^ s[0];
s[0] = a ^ s[1];
s[1] = s[2];
s[2] = s[3];
s[3] = s[4];
s[4] = s[5];
s[5] = s[6];
s[6] = s[7];
s[7] = s[8];
s[8] = a ^ s[9];
s[9] = a ^ s[10];
s[10] = a ^ s[11];
s[11] = a;
}
return load_i(s, 12);
}
static uint16_t crc15(const uint8_t buf[], int len)
{
uint8_t s[15];
uint8_t a;
for (int i=0;i<15;i++)
s[i] = 1;
for (int i=0;i<len;i++) {
a = buf[i] ^ s[0];
s[0] = a ^ s[1];
s[1] = s[2];
s[2] = s[3];
s[3] = a ^ s[4];
s[4] = a ^ s[5];
s[5] = s[6];
s[6] = s[7];
s[7] = a ^ s[8];
s[8] = a ^ s[9];
s[9] = s[10];
s[10] = s[11];
s[11] = s[12];
s[12] = a ^ s[13];
s[13] = s[14];
s[14] = a;
}
return load_i(s, 15);
}
static uint16_t crc16cac(const uint8_t buf[], int len)
{
uint32_t crc = 0xc3ee; //not sure why this though
uint32_t poly = (1<<12) + (1<<5) + 1; //poly is fine
for (int i=0;i<len;i++)
{
crc = ((crc << 1) | buf[i]) & 0x1ffff;
if(crc & 0x10000) crc = (crc & 0xffff) ^ poly;
}
crc = crc ^ 0xffff;
return crc & 0xffff;
}
static uint8_t crc7_scch(uint8_t bits[], int len)
{
uint8_t s[7];
uint8_t a;
for (int i=0;i<7;i++)
s[i] = 1;
for (int i=0;i<len;i++) {
a = bits[i] ^ s[0];
s[0] = s[1];
s[1] = s[2];
s[2] = s[3];
s[3] = a ^ s[4];
s[4] = s[5];
s[5] = s[6];
s[6] = a;
}
return load_i(s, 7);
}
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