fix #269 see below

/**
 * Generate a short suffix used to disambiguate channels that might have the same "name" entered by the human but different PSKs.
 * The ideas is that the PSK changing should be visible to the user so that they see they probably messed up and that's why they
their nodes
 * aren't talking to each other.
 *
 * This string is of the form "#name-XY".
 *
 * Where X is a letter from A to Z (base26), and formed by xoring all the bytes of the PSK together.
 * Y is not yet used but should eventually indicate 'speed/range' of the link
 *
 * This function will also need to be implemented in GUI apps that talk to the radio.
 *
 * https://github.com/meshtastic/Meshtastic-device/issues/269
 */
const char *getChannelName();

src/mesh/NodeDB.cpp

@@ -66,6 +66,33 @@ static uint8_t ourMacAddr[6];
  */
 NodeNum displayedNodeNum;
 
+/**
+ * Generate a short suffix used to disambiguate channels that might have the same "name" entered by the human but different PSKs.
+ * The ideas is that the PSK changing should be visible to the user so that they see they probably messed up and that's why they
+their nodes
+ * aren't talking to each other.
+ *
+ * This string is of the form "#name-XY".
+ *
+ * Where X is a letter from A to Z (base26), and formed by xoring all the bytes of the PSK together.
+ * Y is not yet used but should eventually indicate 'speed/range' of the link
+ *
+ * This function will also need to be implemented in GUI apps that talk to the radio.
+ *
+ * https://github.com/meshtastic/Meshtastic-device/issues/269
+ */
+const char *getChannelName()
+{
+    static char buf[32];
+
+    uint8_t code = 0;
+    for (int i = 0; i < sizeof(channelSettings.psk.size); i++)
+        code ^= channelSettings.psk.bytes[i];
+
+    snprintf(buf, sizeof(buf), "#%s-%c", channelSettings.name, 'A' + (code % 26));
+    return buf;
+}
+
 NodeDB::NodeDB() : nodes(devicestate.node_db), numNodes(&devicestate.node_db_count) {}
 
 void NodeDB::resetRadioConfig()

src/mesh/NodeDB.h

@@ -1,12 +1,12 @@
 #pragma once
 
+#include "Observer.h"
 #include <Arduino.h>
 #include <assert.h>
-#include "Observer.h"
 
 #include "MeshTypes.h"
-#include "mesh-pb-constants.h"
 #include "NodeStatus.h"
+#include "mesh-pb-constants.h"
 
 extern DeviceState devicestate;
 extern MyNodeInfo &myNodeInfo;
@@ -95,7 +95,8 @@ class NodeDB
     NodeInfo *getOrCreateNode(NodeNum n);
 
     /// Notify observers of changes to the DB
-    void notifyObservers(bool forceUpdate = false) {
+    void notifyObservers(bool forceUpdate = false)
+    {
         // Notify observers of the current node state
         const meshtastic::NodeStatus status = meshtastic::NodeStatus(getNumOnlineNodes(), getNumNodes(), forceUpdate);
         newStatus.notifyObservers(&status);
@@ -115,3 +116,20 @@ class NodeDB
 extern NodeNum displayedNodeNum;
 
 extern NodeDB nodeDB;
+
+/**
+ * Generate a short suffix used to disambiguate channels that might have the same "name" entered by the human but different PSKs.
+ * The ideas is that the PSK changing should be visible to the user so that they see they probably messed up and that's why they
+their nodes
+ * aren't talking to each other.
+ *
+ * This string is of the form "#name-XY".
+ *
+ * Where X is a letter from A to Z (base26), and formed by xoring all the bytes of the PSK together.
+ * Y is not yet used but should eventually indicate 'speed/range' of the link
+ *
+ * This function will also need to be implemented in GUI apps that talk to the radio.
+ *
+ * https://github.com/meshtastic/Meshtastic-device/issues/269
+ */
+const char *getChannelName();

src/mesh/RadioInterface.cpp

@@ -115,6 +115,8 @@ unsigned long hash(char *str)
     return hash;
 }
 
+
+
 #define POWER_DEFAULT 17
 
 /**