Copter: added SYSID_ENFORCE parameter

allows enforcement of SYSID_MYGCS

ArduCopter/GCS_Mavlink.cpp

@@ -2259,3 +2259,17 @@ void Copter::gcs_send_text_fmt(MAV_SEVERITY severity, const char *fmt, ...)
     hal.util->vsnprintf((char *)str, sizeof(str), fmt, arg_list);
     GCS_MAVLINK::send_statustext(severity, 0xFF, str);
 }
+
+/*
+  return true if we will accept this packet. Used to implement SYSID_ENFORCE
+ */
+bool GCS_MAVLINK_Copter::accept_packet(const mavlink_status_t &status, mavlink_message_t &msg)
+{
+    if (!copter.g2.sysid_enforce) {
+        return true;
+    }
+    if (msg.msgid == MAVLINK_MSG_ID_RADIO || msg.msgid == MAVLINK_MSG_ID_RADIO_STATUS) {
+        return true;
+    }
+    return (msg.sysid == copter.g.sysid_my_gcs);
+}

ArduCopter/GCS_Mavlink.h

@@ -13,6 +13,8 @@ protected:
 
     uint32_t telem_delay() const override;
 
+    bool accept_packet(const mavlink_status_t &status, mavlink_message_t &msg) override;
+    
 private:
 
     void handleMessage(mavlink_message_t * msg) override;

ArduCopter/Parameters.cpp

@@ -1031,6 +1031,13 @@ const AP_Param::GroupInfo ParametersG2::var_info[] = {
     // @User: Advanced
     AP_GROUPINFO("ACRO_THR_MID", 10, ParametersG2, acro_thr_mid, ACRO_THR_MID_DEFAULT),
 
+    // @Group: SYSID_ENFORCE
+    // @DisplayName: GCS sysid enforcement
+    // @Description: This controls whether packets from other than the expected GCS system ID will be accepted
+    // @Values: 0:NotEnforced,1:Enforced
+    // @User: Advanced
+    AP_GROUPINFO("SYSID_ENFORCE", 11, ParametersG2, sysid_enforce, 0),
+    
     AP_GROUPEND
 };
 

ArduCopter/Parameters.h

@@ -563,6 +563,9 @@ public:
     AP_Proximity proximity;
 #endif
 
+    // whether to enforce acceptance of packets only from sysid_my_gcs
+    AP_Int8 sysid_enforce;
+    
 #if ADVANCED_FAILSAFE == ENABLED
     // advanced failsafe library
     AP_AdvancedFailsafe_Copter afs;