From 3a73a25c1e2848badf405f19e1c32bc50de471a1 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Sun, 11 Apr 2021 17:31:05 +0100
Subject: [PATCH] Update M17 to the latest secification, removal of the CRC
 from the stream data.

---
 M17Control.cpp     | 27 +++++----------------------
 M17Control.h       |  1 -
 M17Convolution.cpp |  7 +++----
 Version.h          |  2 +-
 4 files changed, 9 insertions(+), 28 deletions(-)

diff --git a/M17Control.cpp b/M17Control.cpp
index f518037..8ee67d4 100644
--- a/M17Control.cpp
+++ b/M17Control.cpp
@@ -75,7 +75,6 @@ m_networkWatchdog(1000U, 0U, 1500U),
 m_elapsed(),
 m_rfFrames(0U),
 m_netFrames(0U),
-m_rfFN(0U),
 m_rfErrs(0U),
 m_rfBits(1U),
 m_rfLSF(),
@@ -194,7 +193,6 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 			m_aveRSSI = m_rssi;
 			m_rssiCount = 1U;
 			m_rfLSFn    = 0U;
-			m_rfFN      = 0U;
 
 #if defined(DUMP_M17)
 			openFile();
@@ -258,22 +256,10 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 		writeFile(data + 2U);
 #endif
 		CM17Convolution conv;
-		unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES];
+		unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES];
 		conv.decodeData(data + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES, frame);
 
-		bool valid = CM17CRC::checkCRC16(frame, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
-		if (valid) {
-			m_rfFN = (frame[0U] << 8) + (frame[1U] << 0);
-		} else {
-			m_rfFN++;
-
-			// The new FN
-			frame[0U] = m_rfFN >> 8;
-			frame[1U] = m_rfFN >> 0;
-
-			// Recalculate the CRC
-			CM17CRC::encodeCRC16(frame, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
-		}
+		unsigned int fn = ((frame[0U] << 8) + (frame[1U] << 0)) & 0x7FU;
 
 		unsigned char rfData[2U + M17_FRAME_LENGTH_BYTES];
 
@@ -310,7 +296,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 			errors += CUtils::countBits(rfData[offset] ^ data[offset]);
 		}
 
-		LogDebug("M17, FN: %u, errs: %u/144 (%.1f%%)", m_rfFN & 0x7FU, errors, float(errors) / 1.44F);
+		LogDebug("M17, FN: %u, errs: %u/144 (%.1f%%)", fn & 0x7FU, errors, float(errors) / 1.44F);
 
 		m_rfBits += M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS;
 		m_rfErrs += errors;
@@ -345,7 +331,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 			m_rfLSFn = 0U;
 
 		// Only check for the EOT marker if the frame has a valid CRC
-		if (valid && (m_rfFN & 0x8000U) == 0x8000U) {
+		if ((fn & 0x8000U) == 0x8000U) {
 			std::string source = m_rfLSF.getSource();
 			std::string dest   = m_rfLSF.getDest();
 
@@ -520,12 +506,9 @@ void CM17Control::writeNetwork()
 		CM17Utils::combineFragmentLICHFEC(lich1, lich2, lich3, lich4, data + 2U + M17_SYNC_LENGTH_BYTES);
 
 		// Add the FN and the data/audio
-		unsigned char payload[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES];
+		unsigned char payload[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES];
 		::memcpy(payload, netData + 28U, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES);
 
-		// Add the CRC
-		CM17CRC::encodeCRC16(payload, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
-
 		// Add the Convolution FEC
 		CM17Convolution conv;
 		conv.encodeData(payload, data + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES);
diff --git a/M17Control.h b/M17Control.h
index d351099..4b8b485 100644
--- a/M17Control.h
+++ b/M17Control.h
@@ -65,7 +65,6 @@ private:
 	CStopWatch                 m_elapsed;
 	unsigned int               m_rfFrames;
 	unsigned int               m_netFrames;
-	unsigned int               m_rfFN;
 	unsigned int               m_rfErrs;
 	unsigned int               m_rfBits;
 	CM17LSF                    m_rfLSF;
diff --git a/M17Convolution.cpp b/M17Convolution.cpp
index 5a83ab0..b7b17f5 100644
--- a/M17Convolution.cpp
+++ b/M17Convolution.cpp
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2020 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2020,2021 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -32,9 +32,8 @@ const unsigned int PUNCTURE_LIST_LINK_SETUP[] = {
 	449U, 452U, 455U, 462U, 465U, 468U, 471U, 478U, 481U, 484U};
 
 const unsigned int PUNCTURE_LIST_DATA[] = {
-	5U, 11U, 17U, 20U, 23U, 29U, 35U, 46U, 52U, 58U, 61U, 64U, 70U, 76U, 87U, 93U, 99U, 102U, 105U, 111U, 117U, 128U, 134U, 140U,
-	143U, 146U, 152U, 158U, 169U, 175U, 181U, 184U, 187U, 193U, 199U, 210U, 216U, 222U, 225U, 228U, 234U, 240U, 251U, 257U, 263U,
-	266U, 269U, 275U, 281U, 292U, 298U, 304U, 307U, 310U, 316U, 322U};
+	11U, 23U, 35U, 47U, 59U, 71U, 83U, 95U, 107U, 119U, 131U, 143U, 155U, 167U, 179U, 191U, 203U, 215U, 227U, 239U, 251U, 263U,
+	275U, 287U, 299U, 311U, 323U };
 
 const unsigned char BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
 
diff --git a/Version.h b/Version.h
index 486d545..5bef73a 100644
--- a/Version.h
+++ b/Version.h
@@ -19,6 +19,6 @@
 #if !defined(VERSION_H)
 #define	VERSION_H
 
-const char* VERSION = "20210408";
+const char* VERSION = "20210411";
 
 #endif