From c7f1d20c3db4f9ecc18c4bc00e4a61a76a33a936 Mon Sep 17 00:00:00 2001
From: Bryan Biedenkapp <gatekeep@gmail.com>
Date: Mon, 1 Aug 2022 21:23:33 -0400
Subject: [PATCH] experimental support to repeat a TSBK_ISP_EMERG_ALRM_REQ
 locally;

---
 config.example.yml   |  1 +
 p25/Control.cpp      |  1 +
 p25/lc/TSBK.cpp      |  2 +-
 p25/packet/Trunk.cpp | 33 +++++++++++++++++++++++++++++++++
 p25/packet/Trunk.h   |  3 +++
 5 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/config.example.yml b/config.example.yml
index c7cba6ff..312b83a1 100644
--- a/config.example.yml
+++ b/config.example.yml
@@ -70,6 +70,7 @@ protocols:
         noStatusAck: false
         noMessageAck: true
         unitToUnitAvailCheck: true
+        localEmergAlarm: false
         sndcpGrant: false
         silenceThreshold: 124
         disableNetworkHDU: false
diff --git a/p25/Control.cpp b/p25/Control.cpp
index fb8547a1..af321b2d 100644
--- a/p25/Control.cpp
+++ b/p25/Control.cpp
@@ -236,6 +236,7 @@ void Control::setOptions(yaml::Node& conf, const std::string cwCallsign, const s
     m_trunk->m_noMessageAck = p25Protocol["noMessageAck"].as<bool>(true);
     m_trunk->m_unitToUnitAvailCheck = p25Protocol["unitToUnitAvailCheck"].as<bool>(true);
     
+    m_trunk->m_localEmergAlarm = p25Protocol["localEmergAlarm"].as<bool>(false);
     m_trunk->m_sndcpChGrant = p25Protocol["sndcpGrant"].as<bool>(false);
 
     yaml::Node control = p25Protocol["control"];
diff --git a/p25/lc/TSBK.cpp b/p25/lc/TSBK.cpp
index 77234865..4e1f6f49 100644
--- a/p25/lc/TSBK.cpp
+++ b/p25/lc/TSBK.cpp
@@ -692,7 +692,7 @@ void TSBK::encode(uint8_t* data, bool rawTSBK, bool noTrellis)
         tsbkValue = (tsbkValue << 16) + m_dstId;                                    // Talkgroup Address
         tsbkValue = (tsbkValue << 32) + 0;
         break;
-    case TSBK_OSP_DENY_RSP:
+    case TSBK_OSP_DENY_RSP: // TSBK_ISP_EMERG_ALRM_REQ
     case TSBK_OSP_QUE_RSP:
     {
         if (m_response == 0U) {
diff --git a/p25/packet/Trunk.cpp b/p25/packet/Trunk.cpp
index 2ce0d6d7..27cbb7e5 100644
--- a/p25/packet/Trunk.cpp
+++ b/p25/packet/Trunk.cpp
@@ -430,6 +430,9 @@ bool Trunk::process(uint8_t* data, uint32_t len, bool preDecoded)
                     ::ActivityLog("P25", true, "emergency alarm request request from %u", srcId);
 
                     writeRF_TSDU_ACK_FNE(srcId, TSBK_ISP_EMERG_ALRM_REQ, false, true);
+                    if (m_localEmergAlarm) {
+                        writeRF_TSDU_Emerg_Alrm(srcId, dstId);
+                    }
                 }
                 break;
             case TSBK_IOSP_GRP_AFF:
@@ -1231,6 +1234,35 @@ void Trunk::writeRF_TSDU_U_Reg_Cmd(uint32_t dstId)
     writeRF_TSDU_SBF(true);
 }
 
+/// <summary>
+/// Helper to write a emergency alarm packet.
+/// </summary>
+/// <param name="srcId"></param>
+/// <param name="dstId"></param>
+void Trunk::writeRF_TSDU_Emerg_Alrm(uint32_t srcId, uint32_t dstId)
+{
+    uint8_t lco = m_rfTSBK.getLCO();
+    uint32_t _srcId = m_rfTSBK.getSrcId();
+
+    m_rfTSBK.setLCO(TSBK_ISP_EMERG_ALRM_REQ);
+    m_rfTSBK.setSrcId(P25_WUID_FNE);
+    m_rfTSBK.setService(0U);
+    m_rfTSBK.setResponse(0U);
+
+    m_rfTSBK.setSrcId(srcId);
+    m_rfTSBK.setDstId(dstId);
+
+    if (m_verbose) {
+        LogMessage(LOG_RF, P25_TSDU_STR ", TSBK_ISP_EMERG_ALRM_REQ (Emergency Alarm Request), srcId = %u, dstId = %u",
+            srcId, dstId);
+    }
+
+    writeRF_TSDU_SBF(true);
+
+    m_rfTSBK.setLCO(lco);
+    m_rfTSBK.setSrcId(_srcId);
+}
+
 /// <summary>
 /// Helper to write a Motorola patch packet.
 /// </summary>
@@ -1335,6 +1367,7 @@ Trunk::Trunk(Control* p25, network::BaseNetwork* network, bool dumpTSBKData, boo
     m_adjSiteUpdateTimer(1000U),
     m_adjSiteUpdateInterval(ADJ_SITE_TIMER_TIMEOUT),
     m_ctrlTSDUMBF(true),
+    m_localEmergAlarm(false),
     m_sndcpChGrant(false),
     m_dumpTSBK(dumpTSBKData),
     m_verbose(verbose),
diff --git a/p25/packet/Trunk.h b/p25/packet/Trunk.h
index d699c654..aac1870a 100644
--- a/p25/packet/Trunk.h
+++ b/p25/packet/Trunk.h
@@ -106,6 +106,8 @@ namespace p25
             void writeRF_TSDU_Grp_Aff_Q(uint32_t dstId);
             /// <summary>Helper to write a unit registration command packet.</summary>
             void writeRF_TSDU_U_Reg_Cmd(uint32_t dstId);
+            /// <summary>Helper to write a emergency alarm packet.</summary>
+            void writeRF_TSDU_Emerg_Alrm(uint32_t srcId, uint32_t dstId);
 
             /// <summary>Helper to write a Motorola patch packet.</summary>
             void writeRF_TSDU_Mot_Patch(uint32_t group1, uint32_t group2, uint32_t group3);
@@ -169,6 +171,7 @@ namespace p25
 
             bool m_ctrlTSDUMBF;
 
+            bool m_localEmergAlarm;
             bool m_sndcpChGrant;
 
             bool m_dumpTSBK;