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demod_flex.c
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demod_flex.c
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/*
* demod_flex.c
*
* Copyright 2004,2006,2010 Free Software Foundation, Inc.
* Copyright (C) 2015 Craig Shelley (craig@microtron.org.uk)
*
* FLEX Radio Paging Decoder - Adapted from GNURadio for use with Multimon
*
* GNU Radio 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.
*
* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
/*
* Modification (to this file) made by Ryan Farley (rfarley3@github)
* - Issue #139 !160 handle edge cases for start and end offsets (long vs short, single vs group)
* - Resolve type ambiguity to improve stability after Raspberry Pi compile
* - Compare algorithms to other open source libraries to reconcile group bit, frag bit, and capcode decode
* - Refactor message printing to single line, only printables, encoded % fmtstr directives
* Version 0.9.3v (28 Jan 2020)
* Modification made by bierviltje and implemented by Bruce Quinton (Zanoroy@gmail.com)
* - Issue #123 created by bierviltje (https://github.com/bierviltje) - Feature request: FLEX: put group messages in an array/list
* - This also changed the delimiter to a | rather than a space
* Version 0.9.2v (03 Apr 2019)
* Modification made by Bruce Quinton (Zanoroy@gmail.com)
* - Issue #120 created by PimHaarsma - Flex Tone-Only messages with short numeric body Bug fixed using code documented in the ticket system
* Version 0.9.1v (10 Jan 2019)
* Modification (to this file) made by Rob0101
* Fixed marking messages with K,F,C - One case had a 'C' marked as a 'K'
* Version 0.9.0v (22 May 2018)
* Modification (to this file) made by Bruce Quinton (zanoroy@gmail.com)
* - Addded Define at top of file to modify the way missed group messages are reported in the debug output (default is 1; report missed capcodes on the same line)
* REPORT_GROUP_CODES 1 // Report each cleared faulty group capcode : 0 = Each on a new line; 1 = All on the same line;
* Version 0.8.9 (20 Mar 2018)
* Modification (to this file) made by Bruce Quinton (zanoroy@gmail.com)
* - Issue #101 created by bertinhollan (https://github.com/bertinholland): Bug flex: Wrong split up group message after a data corruption frame.
* - Added logic to the FIW decoding that checks for any 'Group Messages' and if the frame has past them remove the group message and log output
* - The following settings (at the top of this file, just under these comments) have changed from:
* PHASE_LOCKED_RATE 0.150
* PHASE_UNLOCKED_RATE 0.150
* these new settings appear to work better when attempting to locate the Sync lock in the message preamble.
* Version 0.8.8v (20 APR 2018)
* Modification (to this file) made by Bruce Quinton (zanoroy@gmail.com)
* - Issue #101 created by bertinhollan (https://github.com/bertinholland): Bug flex: Wrong split up group message after a data corruption frame.
* Version 0.8.7v (11 APR 2018)
* Modification (to this file) made by Bruce Quinton (zanoroy@gmail.com) and Rob0101 (as seen on github: https://github.com/rob0101)
* - Issue *#95 created by rob0101: '-a FLEX dropping first character of some message on regular basis'
* - Implemented Rob0101's suggestion of K, F and C flags to indicate the message fragmentation:
* 'K' message is complete and O'K' to display to the world.
* 'F' message is a 'F'ragment and needs a 'C'ontinuation message to complete it. Message = Fragment + Continuation
* 'C' message is a 'C'ontinuation of another fragmented message
* Version 0.8.6v (18 Dec 2017)
* Modification (to this file) made by Bruce Quinton (Zanoroy@gmail.com) on behalf of bertinhollan (https://github.com/bertinholland)
* - Issue #87 created by bertinhollan: Reported issue is that the flex period timeout was too short and therefore some group messages were not being processed correctly
* After some testing bertinhollan found that increasing the timeout period fixed the issue in his area. I have done further testing in my local
* area and found the change has not reduced my success rate. I think the timeout is a localisation setting and I have added "DEMOD_TIMEOUT"
* to the definitions in the top of this file (the default value is 100 bertinhollan's prefered value, changed up from 50)
* Version 0.8.5v (08 Sep 2017)
* Modification made by Bruce Quinton (Zanoroy@gmail.com)
* - Issue #78 - Found a problem in the length detection sequence, modified the if statement to ensure the message length is
* only checked for Aplha messages, the other types calculate thier length while decoding
* Version 0.8.4v (05 Sep 2017)
* Modification made by Bruce Quinton (Zanoroy@gmail.com)
* - Found a bug in the code that was not handling multiple group messages within the same frame,
* and the long address bit was being miss treated in the same cases. Both issue have been fixed but further testing will help.
* Version 0.8.3v (22 Jun 2017)
* Modification made by Bruce Quinton (Zanoroy@gmail.com)
* - I had previously tagged Group Messages as GPN message types,
* this was my own identification rather than a Flex standard type.
* Now that I have cleaned up all identified (so far) issues I have changed back to the correct Flex message type of ALN (Alpha).
* Version 0.8.2v (21 Jun 2017)
* Modification made by Bruce Quinton (Zanoroy@gmail.com)
* - Fixed group messaging capcode issue - modified the Capcode Array to be int64_t rather than int (I was incorrectly casting the long to an int)
* Version 0.8.1v (16 Jun 2017)
* Modification made by Bruce Quinton (Zanoroy@gmail.com)
* - Added Debugging to help track the group messaging issues
* - Improved Alpha output and removed several loops to improve CPU cycles
* Version 0.8v (08 Jun 2017)
* Modification made by Bruce Quinton (Zanoroy@gmail.com)
* - Added Group Messaging
* - Fixed Phase adjustments (phasing as part of Symbol identification)
* - Fixed Alpha numeric length adjustments to stop "Invalid Vector" errors
* - Fixed numeric message treatment
* - Fixed invalid identification of "unknown" messages
* - Added 3200 2 fsk identification to all more message types to be processed (this was a big deal for NZ)
* - Changed uint to int variables
*
*/
/* ---------------------------------------------------------------------- */
#include "multimon.h"
#include "filter.h"
#include "BCHCode.h"
#include <math.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
/* ---------------------------------------------------------------------- */
#define FREQ_SAMP 22050
#define FILTLEN 1
#define REPORT_GROUP_CODES 1 // Report each cleared faulty group capcode : 0 = Each on a new line; 1 = All on the same line;
#define FLEX_SYNC_MARKER 0xA6C6AAAAul // Synchronisation code marker for FLEX
#define SLICE_THRESHOLD 0.667 // For 4 level code, levels 0 and 3 have 3 times the amplitude of levels 1 and 2, so quantise at 2/3
#define DC_OFFSET_FILTER 0.010 // DC Offset removal IIR filter response (seconds)
#define PHASE_LOCKED_RATE 0.045 // Correction factor for locked state
#define PHASE_UNLOCKED_RATE 0.050 // Correction factor for unlocked state
#define LOCK_LEN 24 // Number of symbols to check for phase locking (max 32)
#define IDLE_THRESHOLD 0 // Number of idle codewords allowed in data section
#define CAPCODES_INDEX 0
#define DEMOD_TIMEOUT 100 // Maximum number of periods with no zero crossings before we decide that the system is not longer within a Timing lock.
#define GROUP_BITS 17 // Centralized maximum of group msg cache
#define PHASE_WORDS 88 // per spec, there are 88 4B words per frame
// there are 3 chars per message word (mw)
// there are at most 88 words per frame's phase buffer of a page
// but at least 1 BIW 1 AW 1 VW, so max 85 data words (dw) for text
// each dw is 3 chars of 7b ASCII (21 bits of text, 11 bits of checksum)
// this is 256, BUT each char could need to be escaped (%, \n, \r, \t), so double it
#define MAX_ALN 512 // max possible ALN characters
enum Flex_PageTypeEnum {
FLEX_PAGETYPE_SECURE,
FLEX_PAGETYPE_SHORT_INSTRUCTION,
FLEX_PAGETYPE_TONE,
FLEX_PAGETYPE_STANDARD_NUMERIC,
FLEX_PAGETYPE_SPECIAL_NUMERIC,
FLEX_PAGETYPE_ALPHANUMERIC,
FLEX_PAGETYPE_BINARY,
FLEX_PAGETYPE_NUMBERED_NUMERIC
};
enum Flex_StateEnum {
FLEX_STATE_SYNC1,
FLEX_STATE_FIW,
FLEX_STATE_SYNC2,
FLEX_STATE_DATA
};
struct Flex_Demodulator {
unsigned int sample_freq;
double sample_last;
int locked;
int phase;
unsigned int sample_count;
unsigned int symbol_count;
double envelope_sum;
int envelope_count;
uint64_t lock_buf;
int symcount[4];
int timeout;
int nonconsec;
unsigned int baud; // Current baud rate
};
struct Flex_GroupHandler {
int64_t GroupCodes[GROUP_BITS][1000];
int GroupCycle[GROUP_BITS];
int GroupFrame[GROUP_BITS];
};
struct Flex_Modulation {
double symbol_rate;
double envelope;
double zero;
};
struct Flex_State {
unsigned int sync2_count;
unsigned int data_count;
unsigned int fiwcount;
enum Flex_StateEnum Current;
enum Flex_StateEnum Previous;
};
struct Flex_Sync {
unsigned int sync; // Outer synchronization code
unsigned int baud; // Baudrate of SYNC2 and DATA
unsigned int levels; // FSK encoding of SYNC2 and DATA
unsigned int polarity; // 0=Positive (Normal) 1=Negative (Inverted)
uint64_t syncbuf;
};
struct Flex_FIW {
unsigned int rawdata;
unsigned int checksum;
unsigned int cycleno;
unsigned int frameno;
unsigned int fix3;
};
struct Flex_Phase {
unsigned int buf[PHASE_WORDS];
int idle_count;
};
struct Flex_Data {
int phase_toggle;
unsigned int data_bit_counter;
struct Flex_Phase PhaseA;
struct Flex_Phase PhaseB;
struct Flex_Phase PhaseC;
struct Flex_Phase PhaseD;
};
struct Flex_Decode {
enum Flex_PageTypeEnum type;
int long_address;
int64_t capcode;
struct BCHCode * BCHCode;
};
struct Flex {
struct Flex_Demodulator Demodulator;
struct Flex_Modulation Modulation;
struct Flex_State State;
struct Flex_Sync Sync;
struct Flex_FIW FIW;
struct Flex_Data Data;
struct Flex_Decode Decode;
struct Flex_GroupHandler GroupHandler;
};
int is_alphanumeric_page(struct Flex * flex) {
if (flex==NULL) return 0;
return (flex->Decode.type == FLEX_PAGETYPE_ALPHANUMERIC ||
flex->Decode.type == FLEX_PAGETYPE_SECURE);
}
int is_numeric_page(struct Flex * flex) {
if (flex==NULL) return 0;
return (flex->Decode.type == FLEX_PAGETYPE_STANDARD_NUMERIC ||
flex->Decode.type == FLEX_PAGETYPE_SPECIAL_NUMERIC ||
flex->Decode.type == FLEX_PAGETYPE_NUMBERED_NUMERIC);
}
int is_tone_page(struct Flex * flex) {
if (flex==NULL) return 0;
return (flex->Decode.type == FLEX_PAGETYPE_TONE);
}
int is_binary_page(struct Flex * flex) {
if (flex==NULL) return 0;
return (flex->Decode.type == FLEX_PAGETYPE_BINARY);
}
unsigned int count_bits(struct Flex * flex, unsigned int data) {
if (flex==NULL) return 0;
#ifdef USE_BUILTIN_POPCOUNT
return __builtin_popcount(data);
#else
unsigned int n = (data >> 1) & 0x77777777;
data = data - n;
n = (n >> 1) & 0x77777777;
data = data - n;
n = (n >> 1) & 0x77777777;
data = data - n;
data = (data + (data >> 4)) & 0x0f0f0f0f;
data = data * 0x01010101;
return data >> 24;
#endif
}
static int bch3121_fix_errors(struct Flex * flex, uint32_t * data_to_fix, char PhaseNo) {
if (flex==NULL) return -1;
int i=0;
int recd[31];
/*Convert the data pattern into an array of coefficients*/
unsigned int data=*data_to_fix;
for (i=0; i<31; i++) {
recd[i] = (data>>30)&1;
data<<=1;
}
/*Decode and correct the coefficients*/
int decode_error=BCHCode_Decode(flex->Decode.BCHCode, recd);
/*Decode successful?*/
if (!decode_error) {
/*Convert the coefficient array back to a bit pattern*/
data=0;
for (i=0; i<31; i++) {
data<<=1;
data|=recd[i];
}
/*Count the number of fixed errors*/
int fixed=count_bits(flex, (*data_to_fix & 0x7FFFFFFF) ^ data);
if (fixed>0) {
verbprintf(3, "FLEX: Phase %c Fixed %i errors @ 0x%08x (0x%08x -> 0x%08x)\n", PhaseNo, fixed, (*data_to_fix&0x7FFFFFFF) ^ data, (*data_to_fix&0x7FFFFFFF), data );
}
/*Write the fixed data back to the caller*/
*data_to_fix=data;
} else {
verbprintf(3, "FLEX: Phase %c Data corruption - Unable to fix errors.\n", PhaseNo);
}
return decode_error;
}
static unsigned int flex_sync_check(struct Flex * flex, uint64_t buf) {
if (flex==NULL) return 0;
// 64-bit FLEX sync code:
// AAAA:BBBBBBBB:CCCC
//
// Where BBBBBBBB is always 0xA6C6AAAA
// and AAAA^CCCC is 0xFFFF
//
// Specific values of AAAA determine what bps and encoding the
// packet is beyond the frame information word
//
// First we match on the marker field with a hamming distance < 4
// Then we match on the outer code with a hamming distance < 4
unsigned int marker = (buf & 0x0000FFFFFFFF0000ULL) >> 16;
unsigned short codehigh = (buf & 0xFFFF000000000000ULL) >> 48;
unsigned short codelow = ~(buf & 0x000000000000FFFFULL);
int retval=0;
if (count_bits(flex, marker ^ FLEX_SYNC_MARKER) < 4 && count_bits(flex, codelow ^ codehigh) < 4 ) {
retval=codehigh;
} else {
retval=0;
}
return retval;
}
static unsigned int flex_sync(struct Flex * flex, unsigned char sym) {
if (flex==NULL) return 0;
int retval=0;
flex->Sync.syncbuf = (flex->Sync.syncbuf << 1) | ((sym < 2)?1:0);
retval=flex_sync_check(flex, flex->Sync.syncbuf);
if (retval!=0) {
flex->Sync.polarity=0;
} else {
/*If a positive sync pattern was not found, look for a negative (inverted) one*/
retval=flex_sync_check(flex, ~flex->Sync.syncbuf);
if (retval!=0) {
flex->Sync.polarity=1;
}
}
return retval;
}
static void decode_mode(struct Flex * flex, unsigned int sync_code) {
if (flex==NULL) return;
// Something is off with these modes:
// * Where is 6400/4?
// * Why are there two 3200/4?
// * Why is there a 1600/4?
struct {
int sync;
unsigned int baud;
unsigned int levels;
} flex_modes[] = {
{ 0x870C, 1600, 2 },
{ 0xB068, 1600, 4 },
{ 0x7B18, 3200, 2 },
{ 0xDEA0, 3200, 4 },
{ 0x4C7C, 3200, 4 },
{0,0,0}
};
int x=0;
int i=0;
for (i=0; flex_modes[i].sync!=0; i++) {
if (count_bits(flex, flex_modes[i].sync ^ sync_code) < 4) {
flex->Sync.sync = sync_code;
flex->Sync.baud = flex_modes[i].baud;
flex->Sync.levels = flex_modes[i].levels;
x = 1;
break;
}
}
if(x==0){
verbprintf(3, "FLEX: Sync Code not found, defaulting to 1600bps 2FSK\n");
}
}
static void read_2fsk(struct Flex * flex, unsigned int sym, unsigned int * dat) {
if (flex==NULL) return;
*dat = (*dat >> 1) | ((sym > 1)?0x80000000:0);
}
static int decode_fiw(struct Flex * flex) {
if (flex==NULL) return -1;
unsigned int fiw = flex->FIW.rawdata;
int decode_error = bch3121_fix_errors(flex, &fiw, 'F');
if (decode_error) {
verbprintf(3, "FLEX: Unable to decode FIW, too much data corruption\n");
return 1;
}
// The only relevant bits in the FIW word for the purpose of this function
// are those masked by 0x001FFFFF.
flex->FIW.checksum = fiw & 0xF;
flex->FIW.cycleno = (fiw >> 4) & 0xF;
flex->FIW.frameno = (fiw >> 8) & 0x7F;
flex->FIW.fix3 = (fiw >> 15) & 0x3F;
unsigned int checksum = (fiw & 0xF);
checksum += ((fiw >> 4) & 0xF);
checksum += ((fiw >> 8) & 0xF);
checksum += ((fiw >> 12) & 0xF);
checksum += ((fiw >> 16) & 0xF);
checksum += ((fiw >> 20) & 0x01);
checksum &= 0xF;
if (checksum == 0xF) {
int timeseconds = flex->FIW.cycleno*4*60 + flex->FIW.frameno*4*60/128;
verbprintf(2, "FLEX: FrameInfoWord: cycleno=%02i frameno=%03i fix3=0x%02x time=%02i:%02i\n",
flex->FIW.cycleno,
flex->FIW.frameno,
flex->FIW.fix3,
timeseconds/60,
timeseconds%60);
// Lets check the FrameNo against the expected group message frames, if we have 'Missed a group message' tell the user and clear the Cap Codes
for(int g = 0; g < GROUP_BITS ;g++) {
// Do we have a group message pending for this groupbit?
if(flex->GroupHandler.GroupFrame[g] >= 0)
{
int Reset = 0;
verbprintf(4, "Flex: GroupBit %i, FrameNo: %i, Cycle No: %i target Cycle No: %i\n", g, flex->GroupHandler.GroupFrame[g], flex->GroupHandler.GroupCycle[g], (int)flex->FIW.cycleno);
// Now lets check if its expected in this frame..
if((int)flex->FIW.cycleno == flex->GroupHandler.GroupCycle[g])
{
if(flex->GroupHandler.GroupFrame[g] < (int)flex->FIW.frameno)
{
Reset = 1;
}
}
// Check if we should have sent a group message in the previous cycle
else if(flex->FIW.cycleno == 0)
{
if(flex->GroupHandler.GroupCycle[g] == 15)
{
Reset = 1;
}
}
// If we are waiting for the cycle to roll over then move onto the next for loop item
else if(flex->FIW.cycleno == 15 && flex->GroupHandler.GroupCycle[g] == 0)
{
continue;
}
// Otherwise if the target cycle is less than the current cycle, reset the data
else if(flex->GroupHandler.GroupCycle[g] < (int)flex->FIW.cycleno)
{
Reset = 1;
}
if(Reset == 1)
{
int endpoint = flex->GroupHandler.GroupCodes[g][CAPCODES_INDEX];
if(REPORT_GROUP_CODES > 0)
{
verbprintf(3,"FLEX: Group messages seem to have been missed; Groupbit: %i; Total Capcodes: %i; Clearing Data; Capcodes: ", g, endpoint);
}
for(int capIndex = 1; capIndex <= endpoint; capIndex++)
{
if(REPORT_GROUP_CODES == 0)
{
verbprintf(3,"FLEX: Group messages seem to have been missed; Groupbit: %i; Clearing data; Capcode: [%010" PRId64 "]\n", g, flex->GroupHandler.GroupCodes[g][capIndex]);
}
else
{
if(capIndex > 1)
{
verbprintf(3,",");
}
verbprintf(3,"[%010" PRId64 "]", flex->GroupHandler.GroupCodes[g][capIndex]);
}
}
if(REPORT_GROUP_CODES > 0)
{
verbprintf(3,"\n");
}
// reset the value
flex->GroupHandler.GroupCodes[g][CAPCODES_INDEX] = 0;
flex->GroupHandler.GroupFrame[g] = -1;
flex->GroupHandler.GroupCycle[g] = -1;
}
}
}
return 0;
} else {
verbprintf(3, "FLEX: Bad Checksum 0x%x\n", checksum);
return 1;
}
}
/* Add a character to ALN messages, but avoid buffer overflows and special characters */
unsigned int add_ch(unsigned char ch, unsigned char* buf, unsigned int idx) {
// avoid buffer overflow that has been happening
if (idx >= MAX_ALN) {
verbprintf(3, "FLEX: idx %u >= MAX_ALN %u\n", idx, MAX_ALN);
return 0;
}
// TODO sanitize % or you will have uncontrolled format string vuln
// Originally, this only avoided storing ETX (end of text, 0x03).
// At minimum you'll also want to avoid storing NULL (str term, 0x00),
// otherwise verbprintf will truncate the message.
// ex: if (ch != 0x03 && ch != 0x00) { buf[idx] = ch; return 1; }
// But while we are here, make it print friendly and get it onto a single line
// * remove awkward ctrl chars (del, bs, bell, vertical tab, etc)
// * encode valuable ctrl chars (new line/line feed, carriage ret, tab)
// NOTE: if you post process FLEX ALN output by sed/grep/awk etc on non-printables
// then double check this doesn't mess with your pipeline
if (ch == 0x09 && idx < (MAX_ALN - 2)) { // '\t'
buf[idx] = '\\';
buf[idx + 1] = 't';
return 2;
}
if (ch == 0x0a && idx < (MAX_ALN - 2)) { // '\n'
buf[idx] = '\\';
buf[idx + 1] = 'n';
return 2;
}
if (ch == 0x0d && idx < (MAX_ALN - 2)) { // '\r'
buf[idx] = '\\';
buf[idx + 1] = 'r';
return 2;
}
// unixinput.c::_verbprintf uses this output as a format string
// which introduces an uncontrolled format string vulnerability
// and also, generally, risks stack corruption
if (ch == '%') {
if (idx < (MAX_ALN - 2)) {
buf[idx] = '%';
buf[idx + 1] = '%';
return 2;
}
return 0;
}
// only store ASCII printable
if (ch >= 32 && ch <= 126) {
buf[idx] = ch;
return 1;
}
// if you want all non-printables, show as hex, but also make MAX_ALN 1024
/* if (idx < (MAX_ALN - 4)) {
sprintf(buf + idx, "\\x%02x", ch);
return 4;
}*/
return 0;
}
static void parse_alphanumeric(struct Flex * flex, unsigned int * phaseptr, unsigned int mw1, unsigned int len, int frag, int cont, int flex_groupmessage, int flex_groupbit) {
if (flex==NULL) return;
char frag_flag = '?';
if (cont == 0 && frag == 3) frag_flag = 'K'; // complete, ready to send
if (cont == 0 && frag != 3) frag_flag = 'C'; // incomplete until appended to 1 or more 'F's
if (cont == 1 ) frag_flag = 'F'; // incomplete until a 'C' fragment is appended
verbprintf(0, "%1d.%1d.%c|", frag, cont, frag_flag);
unsigned char message[MAX_ALN];
memset(message, '\0', MAX_ALN);
int currentChar = 0;
// (mw + i) < PHASE_WORDS (aka mw+len<=PW) enforced within decode_phase
for (unsigned int i = 0; i < len; i++) {
unsigned int dw = phaseptr[mw1 + i];
if (i > 0 || frag != 0x03) {
currentChar += add_ch(dw & 0x7Fl, message, currentChar);
}
currentChar += add_ch((dw >> 7) & 0x7Fl, message, currentChar);
currentChar += add_ch((dw >> 14) & 0x7Fl, message, currentChar);
}
message[currentChar] = '\0';
// Implemented bierviltje code from ticket: https://github.com/EliasOenal/multimon-ng/issues/123#
if(flex_groupmessage == 1) {
int endpoint = flex->GroupHandler.GroupCodes[flex_groupbit][CAPCODES_INDEX];
for(int g = 1; g <= endpoint;g++)
{
verbprintf(1, "FLEX Group message output: Groupbit: %i Total Capcodes; %i; index %i; Capcode: [%010" PRId64 "]\n", flex_groupbit, endpoint, g, flex->GroupHandler.GroupCodes[flex_groupbit][g]);
verbprintf(0, "%010" PRId64 "|", flex->GroupHandler.GroupCodes[flex_groupbit][g]);
}
// reset the value
flex->GroupHandler.GroupCodes[flex_groupbit][CAPCODES_INDEX] = 0;
flex->GroupHandler.GroupFrame[flex_groupbit] = -1;
flex->GroupHandler.GroupCycle[flex_groupbit] = -1;
}
verbprintf(0, message);
}
static void parse_numeric(struct Flex * flex, unsigned int * phaseptr, int j) {
if (flex==NULL) return;
unsigned const char flex_bcd[17] = "0123456789 U -][";
int w1 = phaseptr[j] >> 7;
int w2 = w1 >> 7;
w1 = w1 & 0x7f;
w2 = (w2 & 0x07) + w1; // numeric message is 7 words max
// Get first dataword from message field or from second
// vector word if long address
int dw;
if(!flex->Decode.long_address) {
dw = phaseptr[w1];
w1++;
w2++;
} else {
dw = phaseptr[j+1];
}
unsigned char digit = 0;
int count = 4;
if(flex->Decode.type == FLEX_PAGETYPE_NUMBERED_NUMERIC) {
count += 10; // Skip 10 header bits for numbered numeric pages
} else {
count += 2; // Otherwise skip 2
}
int i;
for(i = w1; i <= w2; i++) {
int k;
for(k = 0; k < 21; k++) {
// Shift LSB from data word into digit
digit = (digit >> 1) & 0x0F;
if(dw & 0x01) {
digit ^= 0x08;
}
dw >>= 1;
if(--count == 0) {
// The following if statement removes spaces between the numbers
if(digit != 0x0C) {// Fill
verbprintf(0, "%c", flex_bcd[digit]);
}
count = 4;
}
}
dw = phaseptr[i];
}
}
static void parse_tone_only(struct Flex * flex, unsigned int * phaseptr, int j) {
if (flex==NULL) return;
unsigned const char flex_bcd[17] = "0123456789 U -][";
// message type
// 1=tone-only, 0=short numeric
int w1 = phaseptr[j] >> 7 & 0x03;
if(!w1)
{
unsigned char digit = 0;
int i;
for (i=9; i<=17; i+=4)
{
digit = (phaseptr[j] >> i) & 0x0f;
verbprintf(0, "%c", flex_bcd[digit]);
}
if (flex->Decode.long_address)
{
for (i=0; i<=16; i+=4)
{
digit = (phaseptr[j+1] >> i) & 0x0f;
verbprintf(0, "%c", flex_bcd[digit]);
}
}
}
}
static void parse_binary(struct Flex * flex, unsigned int * phaseptr, unsigned int mw1, unsigned int len) {
if (flex==NULL) return;
for (unsigned int i = 0; i < len; i++) {
verbprintf(0, "%08x", phaseptr[mw1 + i]);
if (i < (len - 1))
verbprintf(0, " ");
}
}
static void decode_phase(struct Flex * flex, char PhaseNo) {
if (flex==NULL) return;
verbprintf(3, "FLEX: Decoding phase %c\n", PhaseNo);
uint32_t *phaseptr=NULL;
switch (PhaseNo) {
case 'A': phaseptr=flex->Data.PhaseA.buf; break;
case 'B': phaseptr=flex->Data.PhaseB.buf; break;
case 'C': phaseptr=flex->Data.PhaseC.buf; break;
case 'D': phaseptr=flex->Data.PhaseD.buf; break;
}
for (unsigned int i = 0; i < PHASE_WORDS; i++) {
int decode_error=bch3121_fix_errors(flex, &phaseptr[i], PhaseNo);
if (decode_error) {
verbprintf(3, "FLEX: Garbled message at block %u\n", i);
// If the previous frame was a short message then we need to Null out the Group Message pointer
// this issue and sugested resolution was presented by 'bertinholland'
return;
}
/*Extract just the message bits*/
phaseptr[i]&=0x1FFFFFL;
}
// Block information word is the first data word in frame
uint32_t biw = phaseptr[0];
// Nothing to see here, please move along
if (biw == 0 || (biw & 0x1FFFFFL) == 0x1FFFFFL) {
verbprintf(3, "FLEX: Nothing to see here, please move along\n");
return;
}
// Address start address is bits 9-8, plus one for offset (to account for biw)
unsigned int aoffset = ((biw >> 8) & 0x3L) + 1;
// Vector start index is bits 15-10
unsigned int voffset = (biw >> 10) & 0x3fL;
if (voffset < aoffset) {
verbprintf(3, "FLEX: Invalid biw");
return;
}
// long addresses use double AW and VW, so there are anywhere between ceil(v-a/2) to v-a pages in this frame
verbprintf(3, "FLEX: BlockInfoWord: (Phase %c) BIW:%08X AW %02u VW %02u (up to %u pages)\n", PhaseNo, biw, aoffset, voffset, voffset-aoffset);
int flex_groupmessage = 0;
int flex_groupbit = 0;
// Iterate through pages and dispatch to appropriate handler
for (unsigned int i = aoffset; i < voffset; i++) {
verbprintf(3, "FLEX: Processing page offset #%u AW:%08X VW:%08X\n", i - aoffset + 1, phaseptr[i], phaseptr[voffset + i - aoffset]);
if (phaseptr[i] == 0 ||
(phaseptr[i] & 0x1FFFFFL) == 0x1FFFFFL) {
verbprintf(3, "FLEX: Idle codewords, invalid address\n");
continue;
}
/*********************
* Parse AW
*/
uint32_t aiw = phaseptr[i];
flex->Decode.long_address = (aiw < 0x8001L) ||
(aiw > 0x1E0000L && aiw < 0x1F0001L) ||
(aiw > 0x1F7FFEL);
flex->Decode.capcode = aiw - 0x8000L; // if short address
if (flex->Decode.long_address) {
// Couldn't find spec on this, credit to PDW
flex->Decode.capcode = phaseptr[i + 1] ^ 0x1FFFFFL;
// 0x8000 or 32768 is 16b, use as upper part of 64b capcode
flex->Decode.capcode = flex->Decode.capcode << 15;
// add in 2068480 and first word, credit to PDW
// NOTE per PDW: this is not number given (2067456) in the patent for FLEX
flex->Decode.capcode += 2068480L + aiw;
}
if (flex->Decode.capcode > 4297068542LL || flex->Decode.capcode < 0) {
// Invalid address (by spec, maximum address)
verbprintf(3, "FLEX: Invalid address, capcode out of range %" PRId64 "\n", flex->Decode.capcode);
continue;
}
verbprintf(3, "FLEX: CAPCODE:%016" PRIx64 " %" PRId64 "\n", flex->Decode.capcode, flex->Decode.capcode);
flex_groupmessage = 0;
flex_groupbit = 0;
if ((flex->Decode.capcode >= 2029568) && (flex->Decode.capcode <= 2029583)) {
flex_groupmessage = 1;
flex_groupbit = flex->Decode.capcode - 2029568;
if(flex_groupbit < 0) continue;
}
if (flex_groupmessage && flex->Decode.long_address) {
// Invalid (by spec)
verbprintf(3, "FLEX: Don't process group messages if a long address\n");
return;
}
verbprintf(3, "FLEX: AIW %u: capcode:%" PRId64 " long:%d group:%d groupbit:%d\n", i, flex->Decode.capcode, flex->Decode.long_address, flex_groupmessage, flex_groupbit);
/*********************
* Parse VW
*/
// Parse vector information word for address @ offset 'i'
unsigned int j = voffset+i-aoffset; // Start of vector field for address @ i
uint32_t viw = phaseptr[j];
flex->Decode.type = ((viw >> 4) & 0x7L);
unsigned int mw1 = (viw >> 7) & 0x7FL;
unsigned int len = (viw >> 14) & 0x7FL;
unsigned int hdr;
if (flex->Decode.long_address) {
// the header is within the next VW
hdr = j + 1;
if (len >= 1) {
// per PDW
len--;
}
} else { // if short address
// the header is within the message
hdr = mw1;
mw1++;
if (!flex_groupmessage && len >= 1) {
// not in spec, possible decode issue, but this fixed repeatedly observed len issues
len--;
}
}
if (hdr >= PHASE_WORDS) {
verbprintf(3, "FLEX: Invalid VIW\n");
continue;
}
// get message fragment number (bits 11 and 12) from first header word
// if frag != 3 then this is a continued message
int frag = (int) (phaseptr[hdr] >> 11) & 0x3L;
// which spec documents a cont flag? it is used to derive the K/F/C frag_flag
int cont = (int) (phaseptr[hdr] >> 10) & 0x1L;;
verbprintf(3, "FLEX: VIW %u: type:%d mw1:%u len:%u frag:%i\n", j, flex->Decode.type, mw1, len, frag);
if (flex->Decode.type == FLEX_PAGETYPE_SHORT_INSTRUCTION)
{
// if (flex_groupmessage == 1) continue;
unsigned int iAssignedFrame = (int)((viw >> 10) & 0x7f); // Frame with groupmessage
int groupbit = (int)((viw >> 17) & 0x7f); // Listen to this groupcode
////////#############################################################################
////////#############################################################################
flex->GroupHandler.GroupCodes[groupbit][CAPCODES_INDEX]++;
int CapcodePlacement = flex->GroupHandler.GroupCodes[groupbit][CAPCODES_INDEX];
verbprintf(1, "FLEX: Found Short Instruction, Group bit: %i capcodes in group so far %i, adding Capcode: [%010" PRId64 "]\n", groupbit, CapcodePlacement, flex->Decode.capcode);
flex->GroupHandler.GroupCodes[groupbit][CapcodePlacement] = flex->Decode.capcode;
flex->GroupHandler.GroupFrame[groupbit] = iAssignedFrame;
// Ok, so the cycle and frame can be used to make sure we haven't missed the message frame.
// but the cycle is 0 - 15 and the frame is 0 - 127
if(iAssignedFrame > flex->FIW.frameno)
{
flex->GroupHandler.GroupCycle[groupbit] = (int)flex->FIW.cycleno;
verbprintf(4, "FLEX: Message frame is in this cycle: %i\n", flex->GroupHandler.GroupCycle[groupbit]);
}
else
{
if(flex->FIW.cycleno == 15)
{
flex->GroupHandler.GroupCycle[groupbit] = 0;
}
else
{
flex->GroupHandler.GroupCycle[groupbit] = (int)flex->FIW.cycleno++;
}
verbprintf(4, "FLEX: Message frame is in the next cycle: %i\n", flex->GroupHandler.GroupCycle[groupbit]);
}
// Nothing else to do with this word.. move on!!
continue;
}
// mw1 == 0, or anything less than the offset after all the VIW, is bad
if (len < 1 || mw1 < (voffset + (voffset - aoffset)) || mw1 >= PHASE_WORDS) {
verbprintf(3, "FLEX: Invalid VIW\n");
continue;
}
// mw1 + len == 89 was observed, but still contained valid page, so truncate
if ((mw1 + len) > PHASE_WORDS){
len = PHASE_WORDS - mw1;
}
if (is_tone_page(flex))
mw1 = len = 0;
verbprintf(0, "FLEX|%i/%i|%02i.%03i.%c|%010" PRId64 "|%c%c|%1d|", flex->Sync.baud, flex->Sync.levels, flex->FIW.cycleno, flex->FIW.frameno, PhaseNo, flex->Decode.capcode, (flex->Decode.long_address ? 'L' : 'S'), (flex_groupmessage ? 'G' : 'S'), flex->Decode.type);
// Check if this is an alpha message
if (is_alphanumeric_page(flex)) {
verbprintf(0, "ALN|");
parse_alphanumeric(flex, phaseptr, mw1, len, frag, cont, flex_groupmessage, flex_groupbit);
}
else if (is_numeric_page(flex)) {
verbprintf(0, "NUM|");
parse_numeric(flex, phaseptr, j);
}
else if (is_tone_page(flex)) {
verbprintf(0, "TON|");
parse_tone_only(flex, phaseptr, j);
}
else if (is_binary_page(flex)) {
verbprintf(0, "BIN|");
parse_binary(flex, phaseptr, mw1, len);
}
else {
verbprintf(0, "UNK|");
parse_binary(flex, phaseptr, mw1, len);
}
verbprintf(0, "\n");
// long addresses eat 2 aw and 2 vw, so skip the next aw-vw pair
if (flex->Decode.long_address) {
i++;
}
}
}
static void clear_phase_data(struct Flex * flex) {
if (flex==NULL) return;
int i;
for (i = 0; i < PHASE_WORDS; i++) {
flex->Data.PhaseA.buf[i]=0;
flex->Data.PhaseB.buf[i]=0;
flex->Data.PhaseC.buf[i]=0;
flex->Data.PhaseD.buf[i]=0;
}
flex->Data.PhaseA.idle_count=0;
flex->Data.PhaseB.idle_count=0;
flex->Data.PhaseC.idle_count=0;
flex->Data.PhaseD.idle_count=0;
flex->Data.phase_toggle=0;
flex->Data.data_bit_counter=0;
}
static void decode_data(struct Flex * flex) {
if (flex==NULL) return;
if (flex->Sync.baud == 1600) {
if (flex->Sync.levels==2) {
decode_phase(flex, 'A');
} else {
decode_phase(flex, 'A');
decode_phase(flex, 'B');
}
} else {
if (flex->Sync.levels==2) {
decode_phase(flex, 'A');
decode_phase(flex, 'C');
} else {
decode_phase(flex, 'A');
decode_phase(flex, 'B');
decode_phase(flex, 'C');
decode_phase(flex, 'D');
}
}
}
static int read_data(struct Flex * flex, unsigned char sym) {
if (flex==NULL) return -1;
// Here is where we output a 1 or 0 on each phase according
// to current FLEX mode and symbol value. Unassigned phases
// are zero from the enter_idle() initialization.
//
// FLEX can transmit the data portion of the frame at either
// 1600 bps or 3200 bps, and can use either two- or four-level
// FSK encoding.