From 8b38fdb6a26bde6fa65c462565f030c9c9659eb4 Mon Sep 17 00:00:00 2001
From: tadscottsmith <78445808+tadscottsmith@users.noreply.github.com>
Date: Tue, 21 May 2024 20:51:59 -0500
Subject: [PATCH] Improve control channel detection. (#956)

---
 trunk-recorder/monitor_systems.cc    | 19 ++++++++++++++++---
 trunk-recorder/monitor_systems.h     |  1 +
 trunk-recorder/systems/p25_parser.cc | 11 +++++++++--
 trunk-recorder/systems/parser.h      |  2 ++
 4 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/trunk-recorder/monitor_systems.cc b/trunk-recorder/monitor_systems.cc
index c9d49ad2c..7fb235012 100644
--- a/trunk-recorder/monitor_systems.cc
+++ b/trunk-recorder/monitor_systems.cc
@@ -546,7 +546,7 @@ void handle_call_update(TrunkMessage message, System *sys, std::vector<Call *> &
   }
 }
 
-void handle_message(std::vector<TrunkMessage> messages, System *sys, Config &config, std::vector<Source *> &sources, std::vector<Call *> &calls) {
+void handle_message(std::vector<TrunkMessage> messages, System *sys, Config &config, std::vector<Source *> &sources, std::vector<Call *> &calls, gr::top_block_sptr &tb) {
   for (std::vector<TrunkMessage>::iterator it = messages.begin(); it != messages.end(); it++) {
     TrunkMessage message = *it;
 
@@ -624,6 +624,19 @@ void handle_message(std::vector<TrunkMessage> messages, System *sys, Config &con
       unit_answer_request(sys, message.source, message.talkgroup);
       break;
 
+    case INVALID_CC_MESSAGE:
+    {
+      //Do not count messages that aren't valid TSBK or MBTs.
+      int msg_count = sys->get_message_count();
+      if(msg_count > 1){
+        sys->set_message_count(msg_count - 1);
+      }
+    }
+
+    case TDULC:
+      retune_system(sys,tb,sources);
+      break;
+
     case UNKNOWN:
       break;
     }
@@ -811,13 +824,13 @@ int monitor_messages(Config &config, gr::top_block_sptr &tb, std::vector<Source
 
           if (system->get_system_type() == "smartnet") {
             trunk_messages = smartnet_parser->parse_message(msg->to_string(), system);
-            handle_message(trunk_messages, system, config, sources, calls);
+            handle_message(trunk_messages, system, config, sources, calls, tb);
             plugman_trunk_message(trunk_messages, system);
           }
 
           if (system->get_system_type() == "p25") {
             trunk_messages = p25_parser->parse_message(msg, system);
-            handle_message(trunk_messages, system, config, sources, calls);
+            handle_message(trunk_messages, system, config, sources, calls, tb);
             plugman_trunk_message(trunk_messages, system);
           }
 
diff --git a/trunk-recorder/monitor_systems.h b/trunk-recorder/monitor_systems.h
index e4889e1b4..6b30acbc9 100644
--- a/trunk-recorder/monitor_systems.h
+++ b/trunk-recorder/monitor_systems.h
@@ -15,4 +15,5 @@
 #include <gnuradio/top_block.h>
 
 int monitor_messages(Config &config, gr::top_block_sptr &tb, std::vector<Source *> &sources, std::vector<System *> &systems, std::vector<Call *> &calls);
+void retune_system(System *sys, gr::top_block_sptr &tb, std::vector<Source *> &sources);
 #endif
\ No newline at end of file
diff --git a/trunk-recorder/systems/p25_parser.cc b/trunk-recorder/systems/p25_parser.cc
index 74bf9fc15..0c7633886 100644
--- a/trunk-recorder/systems/p25_parser.cc
+++ b/trunk-recorder/systems/p25_parser.cc
@@ -972,6 +972,7 @@ std::vector<TrunkMessage> P25Parser::parse_message(gr::message::sptr msg, System
     return messages;
   } else if (type < 0) {
     BOOST_LOG_TRIVIAL(debug) << "unknown message type " << type;
+    message.message_type = INVALID_CC_MESSAGE;
     messages.push_back(message);
     return messages;
   }
@@ -980,7 +981,8 @@ std::vector<TrunkMessage> P25Parser::parse_message(gr::message::sptr msg, System
 
  if (s.length() < 2) {
     BOOST_LOG_TRIVIAL(error) << "P25 Parse error, s: " << s << " Len: " << s.length();
-    //messages.push_back(message);
+    message.message_type = INVALID_CC_MESSAGE;
+    messages.push_back(message);
     return messages;
   }
 
@@ -1005,7 +1007,7 @@ std::vector<TrunkMessage> P25Parser::parse_message(gr::message::sptr msg, System
   // //" at %f state %d len %d" %(nac, type, time.time(), self.state, len(s))
   if ((type != 7) && (type != 12)) // and nac not in self.trunked_systems:
   {
-    BOOST_LOG_TRIVIAL(debug) << std::hex << "NON TBSK: nac " << nac << std::dec << " type " << type << " size " << msg->to_string().length() << " mesg len: " << msg->length();
+    BOOST_LOG_TRIVIAL(debug) << std::hex << "NON TSBK: nac " << nac << std::dec << " type " << type << " size " << msg->to_string().length() << " mesg len: " << msg->length();
   
     /*
        if not self.configs:
@@ -1081,6 +1083,11 @@ std::vector<TrunkMessage> P25Parser::parse_message(gr::message::sptr msg, System
     return decode_mbt_data(opcode, header, mbt_data, link_id, nac, sys_num);
     // self.trunked_systems[nac].decode_mbt_data(opcode, header << 16, mbt_data
     // << 32)
+  } else if (type == 15)
+  {
+    //TDU with Link Contol. Link Control words should not be seen on an active Control Channel.
+    BOOST_LOG_TRIVIAL(debug) << "P25 Parser: TDULC on control channel. Retuning to next control channel.";
+    message.message_type = TDULC;
   }
   messages.push_back(message);
   return messages;
diff --git a/trunk-recorder/systems/parser.h b/trunk-recorder/systems/parser.h
index dbae447e8..f435d2cb6 100644
--- a/trunk-recorder/systems/parser.h
+++ b/trunk-recorder/systems/parser.h
@@ -20,6 +20,8 @@ enum MessageType {
   UU_ANS_REQ = 13,
   UU_V_GRANT = 14,
   UU_V_UPDATE = 15,
+  INVALID_CC_MESSAGE = 16,
+  TDULC = 17,
   UNKNOWN = 99
 };