just ack the FSC_SEL_CHAN command when requested; fix data offset for TIA-102 DFSI data;

src/common/p25/dfsi/frames/FrameDefines.h

@@ -44,15 +44,17 @@ namespace p25
             namespace FSCMessageType {
                 /** @brief FSC Control Service Message.*/
                 enum E : uint8_t {
-                    FSC_CONNECT = 0,                    //! Establish connection with FSS.
+                    FSC_CONNECT = 0,                    //! Establish connection with FSS
-                    FSC_HEARTBEAT = 1,                  //! Heartbeat/Connectivity Maintenance.
+                    FSC_HEARTBEAT = 1,                  //! Heartbeat/Connectivity Maintenance
                     FSC_ACK = 2,                        //! Control Service Ack.
 
+                    FSC_SEL_CHAN = 5,                   //! Channel Selection
+
                     FSC_REPORT_SEL_MODES = 8,           //! Report Selected Modes
 
-                    FSC_DISCONNECT = 9,                 //! Detach Control Service.
+                    FSC_DISCONNECT = 9,                 //! Detach Control Service
 
-                    FSC_INVALID = 127,                  //! Invalid Control Message.
+                    FSC_INVALID = 127,                  //! Invalid Control Message
                 };
             }
 

src/host/modem/ModemV24.cpp

@@ -1120,7 +1120,7 @@ void ModemV24::convertToAirTIA(const uint8_t *data, uint32_t length)
     uint8_t blockCnt = ctrl.getBlockHeaderCnt();
 
     // iterate through blocks
-    uint8_t hdrOffs = 1U, dataOffs = blockCnt;
+    uint8_t hdrOffs = 1U, dataOffs = blockCnt + 1U;
     for (uint8_t i = 0U; i < blockCnt; i++) {
         BlockHeader hdr = BlockHeader();
         hdr.decode(dfsiData + hdrOffs);

src/host/modem/port/specialized/V24UDPPort.cpp

@@ -514,6 +514,23 @@ void* V24UDPPort::threadedCtrlNetworkRx(void* arg)
                     }
                     break;
 
+                    case FSCMessageType::FSC_SEL_CHAN:
+                    {
+                        FSCACK ackResp = FSCACK();
+                        ackResp.setCorrelationTag(message->getCorrelationTag());
+                        ackResp.setAckMessageId(FSCMessageType::FSC_SEL_CHAN);
+                        ackResp.setResponseCode(FSCAckResponseCode::CONTROL_ACK);
+                        ackResp.setAckCorrelationTag(message->getCorrelationTag());
+                        ackResp.setResponseLength(0U);
+
+                        uint8_t buffer[FSCACK::LENGTH];
+                        ::memset(buffer, 0x00U, FSCACK::LENGTH);
+                        ackResp.encode(buffer);
+
+                        network->m_ctrlFrameQueue->write(buffer, FSCACK::LENGTH, network->m_controlAddr, network->m_ctrlAddrLen);
+                    }
+                    break;
+
                     case FSCMessageType::FSC_REPORT_SEL_MODES:
                     {
                         FSCACK ackResp = FSCACK();