From 8c68dbb6e95b56970e6d451c58f316d22d180fd6 Mon Sep 17 00:00:00 2001
From: Scott Powell <sqij@protonmail.com>
Date: Tue, 11 Mar 2025 14:50:40 +1100
Subject: [PATCH] * Companion: new CMD_GET_CHANNEL, CMD_SET_CHANNEL

---
 examples/companion_radio/main.cpp | 37 ++++++++++++++++++++++++++----
 platformio.ini                    | 36 ++++++++++++++---------------
 src/helpers/BaseChatMesh.cpp      | 38 ++++++++++++++++++++++++++++++-
 src/helpers/BaseChatMesh.h        |  6 ++++-
 4 files changed, 92 insertions(+), 25 deletions(-)

diff --git a/examples/companion_radio/main.cpp b/examples/companion_radio/main.cpp
index 35600de1..c8178b25 100644
--- a/examples/companion_radio/main.cpp
+++ b/examples/companion_radio/main.cpp
@@ -161,6 +161,8 @@ static uint32_t _atoi(const char* sp) {
 #define CMD_HAS_CONNECTION        28
 #define CMD_LOGOUT                29   // 'Disconnect'
 #define CMD_GET_CONTACT_BY_KEY    30
+#define CMD_GET_CHANNEL           31
+#define CMD_SET_CHANNEL           32
 
 #define RESP_CODE_OK                0
 #define RESP_CODE_ERR               1
@@ -178,6 +180,7 @@ static uint32_t _atoi(const char* sp) {
 #define RESP_CODE_DEVICE_INFO      13   // a reply to CMD_DEVICE_QEURY
 #define RESP_CODE_PRIVATE_KEY      14   // a reply to CMD_EXPORT_PRIVATE_KEY
 #define RESP_CODE_DISABLED         15
+#define RESP_CODE_CHANNEL_INFO     16   // a reply to CMD_GET_CHANNEL
 
 // these are _pushed_ to client app at any time
 #define PUSH_CODE_ADVERT            0x80
@@ -216,7 +219,6 @@ class MyMesh : public BaseChatMesh {
   uint32_t expected_ack_crc;  // TODO: keep table of expected ACKs
   uint32_t pending_login;
   uint32_t pending_status;
-  mesh::GroupChannel* _public;
   BaseSerialInterface* _serial;
   unsigned long last_msg_sent;
   ContactsIterator _iter;
@@ -536,7 +538,7 @@ protected:
   void onChannelMessageRecv(const mesh::GroupChannel& channel, int in_path_len, uint32_t timestamp, const char *text) override {
     int i = 0;
     out_frame[i++] = RESP_CODE_CHANNEL_MSG_RECV;
-    out_frame[i++] = 0;  // FUTURE: channel_idx (will just be 'public' for now)
+    out_frame[i++] = findChannelIdx(channel);
     out_frame[i++] = in_path_len < 0 ? 0xFF : in_path_len;
     out_frame[i++] = TXT_TYPE_PLAIN;
     memcpy(&out_frame[i], &timestamp, 4); i += 4;
@@ -713,7 +715,7 @@ public:
     _fs->mkdir("/bl");
 
     loadContacts();
-    _public = addChannel(PUBLIC_GROUP_PSK); // pre-configure Andy's public channel
+    addChannel(PUBLIC_GROUP_PSK); // pre-configure Andy's public channel
 
     _phy->setFrequency(_prefs.freq);
     _phy->setSpreadingFactor(_prefs.sf);
@@ -844,12 +846,14 @@ public:
     } else if (cmd_frame[0] == CMD_SEND_CHANNEL_TXT_MSG) {  // send GroupChannel msg
       int i = 1;
       uint8_t txt_type = cmd_frame[i++];  // should be TXT_TYPE_PLAIN
-      uint8_t channel_idx = cmd_frame[i++];   // reserved future
+      uint8_t channel_idx = cmd_frame[i++];
       uint32_t msg_timestamp;
       memcpy(&msg_timestamp, &cmd_frame[i], 4); i += 4;
       const char *text = (char *) &cmd_frame[i];
 
-      if (txt_type == TXT_TYPE_PLAIN && sendGroupMessage(msg_timestamp, *_public, _prefs.node_name, text, len - i)) {   // hard-coded to 'public' channel for now
+      mesh::GroupChannel channel;
+      bool success = getChannel(channel_idx, channel);
+      if (success && txt_type == TXT_TYPE_PLAIN && sendGroupMessage(msg_timestamp, channel, _prefs.node_name, text, len - i)) {
         writeOKFrame();
       } else {
         writeErrFrame();
@@ -1161,6 +1165,29 @@ public:
       uint8_t* pub_key = &cmd_frame[1];
       stopConnection(pub_key);
       writeOKFrame();
+    } else if (cmd_frame[0] == CMD_GET_CHANNEL && len >= 2) {
+      uint8_t channel_idx = cmd_frame[1];
+      mesh::GroupChannel channel;
+      if (getChannel(channel_idx, channel)) {
+        out_frame[0] = RESP_CODE_CHANNEL_INFO;
+        out_frame[1] = channel_idx;
+        memcpy(&out_frame[2], channel.secret, 16);   // NOTE: only 128-bit supported
+        _serial->writeFrame(out_frame, 2 + 16);
+      } else {
+        writeErrFrame();
+      }
+    } else if (cmd_frame[0] == CMD_SET_CHANNEL && len >= 3+32) {
+      writeErrFrame();  // not supported (yet)
+    } else if (cmd_frame[0] == CMD_SET_CHANNEL && len >= 3+16) {
+      uint8_t channel_idx = cmd_frame[1];
+      mesh::GroupChannel channel;
+      memset(channel.secret, 0, sizeof(channel.secret));
+      memcpy(channel.secret, &cmd_frame[2], 16);   // NOTE: only 128-bit supported
+      if (setChannel(channel_idx, channel)) {
+        writeOKFrame();
+      } else {
+        writeErrFrame();
+      }
     } else {
       writeErrFrame();
       MESH_DEBUG_PRINTLN("ERROR: unknown command: %02X", cmd_frame[0]);
diff --git a/platformio.ini b/platformio.ini
index 6175206f..07ffbf91 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -78,7 +78,7 @@ extends = Heltec_lora32_v2
 build_flags =
   ${Heltec_lora32_v2.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
 ; NOTE: DO NOT ENABLE -->  -D MESH_PACKET_LOGGING=1
 ; NOTE: DO NOT ENABLE -->  -D MESH_DEBUG=1
 build_src_filter = ${Heltec_lora32_v2.build_src_filter}
@@ -93,7 +93,7 @@ extends = Heltec_lora32_v2
 build_flags =
   ${Heltec_lora32_v2.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
   -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
@@ -180,7 +180,7 @@ extends = Heltec_lora32_v3
 build_flags =
   ${Heltec_lora32_v3.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D DISPLAY_CLASS=SSD1306Display
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
 ;  -D ENABLE_PRIVATE_KEY_EXPORT=1
@@ -198,7 +198,7 @@ extends = Heltec_lora32_v3
 build_flags =
   ${Heltec_lora32_v3.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D DISPLAY_CLASS=SSD1306Display
   -D BLE_PIN_CODE=0   ; dynamic, random PIN
   -D BLE_DEBUG_LOGGING=1
@@ -219,7 +219,7 @@ extends = Heltec_lora32_v3
 build_flags =
   ${Heltec_lora32_v3.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D DISPLAY_CLASS=SSD1306Display
   -D WIFI_DEBUG_LOGGING=1
   -D WIFI_SSID='"myssid"'
@@ -268,7 +268,7 @@ extends = Heltec_lora32_v3
 build_flags =
   ${Heltec_lora32_v3.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
   -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
@@ -375,7 +375,7 @@ extends = Xiao_S3_WIO
 build_flags =
   ${Xiao_S3_WIO.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
 ;  -D MESH_PACKET_LOGGING=1
 ;  -D MESH_DEBUG=1
 build_src_filter = ${Xiao_S3_WIO.build_src_filter}
@@ -389,7 +389,7 @@ extends = Xiao_S3_WIO
 build_flags =
   ${Xiao_S3_WIO.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
 ;  -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
@@ -454,7 +454,7 @@ extends = LilyGo_TLora_V2_1_1_6
 build_flags =
   ${LilyGo_TLora_V2_1_1_6.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
 ;  -D MESH_PACKET_LOGGING=1
 ;  -D MESH_DEBUG=1
 build_src_filter = ${LilyGo_TLora_V2_1_1_6.build_src_filter}
@@ -469,7 +469,7 @@ extends = LilyGo_TLora_V2_1_1_6
 build_flags =
   ${LilyGo_TLora_V2_1_1_6.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
 ;  -D ENABLE_PRIVATE_KEY_EXPORT=1
 ; NOTE: DO NOT ENABLE -->  -D MESH_PACKET_LOGGING=1
@@ -486,7 +486,7 @@ extends = LilyGo_TLora_V2_1_1_6
 build_flags =
   ${LilyGo_TLora_V2_1_1_6.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
 ;  -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
@@ -572,7 +572,7 @@ extends = LilyGo_T3S3_sx1262
 build_flags =
   ${LilyGo_T3S3_sx1262.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
 ;  -D ENABLE_PRIVATE_KEY_EXPORT=1
 ; NOTE: DO NOT ENABLE -->  -D MESH_PACKET_LOGGING=1
@@ -588,7 +588,7 @@ extends = LilyGo_T3S3_sx1262
 build_flags =
   ${LilyGo_T3S3_sx1262.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
   -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
@@ -728,7 +728,7 @@ extends = rak4631
 build_flags =
   ${rak4631.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
 ;  -D ENABLE_PRIVATE_KEY_EXPORT=1
 ; NOTE: DO NOT ENABLE -->  -D MESH_PACKET_LOGGING=1
@@ -744,7 +744,7 @@ extends = rak4631
 build_flags =
   ${rak4631.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
   -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
@@ -796,7 +796,7 @@ upload_protocol = nrfutil
 extends = t1000-e
 build_flags = ${t1000-e.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
   -D BLE_DEBUG_LOGGING=1
   -D MESH_PACKET_LOGGING=1
@@ -870,7 +870,7 @@ extends = Heltec_t114
 build_flags =
   ${Heltec_t114.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
   -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
@@ -943,7 +943,7 @@ extends = LilyGo_Techo
 build_flags =
   ${LilyGo_Techo.build_flags}
   -D MAX_CONTACTS=100
-  -D MAX_GROUP_CHANNELS=1
+  -D MAX_GROUP_CHANNELS=8
   -D BLE_PIN_CODE=123456
   -D BLE_DEBUG_LOGGING=1
 ;  -D ENABLE_PRIVATE_KEY_IMPORT=1
diff --git a/src/helpers/BaseChatMesh.cpp b/src/helpers/BaseChatMesh.cpp
index e8e48e53..e44ffcf3 100644
--- a/src/helpers/BaseChatMesh.cpp
+++ b/src/helpers/BaseChatMesh.cpp
@@ -203,7 +203,7 @@ void BaseChatMesh::onAckRecv(mesh::Packet* packet, uint32_t ack_crc) {
 #ifdef MAX_GROUP_CHANNELS
 int BaseChatMesh::searchChannelsByHash(const uint8_t* hash, mesh::GroupChannel dest[], int max_matches) {
   int n = 0;
-  for (int i = 0; i < num_channels && n < max_matches; i++) {
+  for (int i = 0; i < MAX_GROUP_CHANNELS && n < max_matches; i++) {
     if (channels[i].hash[0] == hash[0]) {
       dest[n++] = channels[i];
     }
@@ -602,10 +602,46 @@ mesh::GroupChannel* BaseChatMesh::addChannel(const char* psk_base64) {
   }
   return NULL;
 }
+bool BaseChatMesh::getChannel(int idx, mesh::GroupChannel& dest) {
+  if (idx >= 0 && idx < MAX_GROUP_CHANNELS) {
+    dest = channels[idx];
+    return true;
+  }
+  return false;
+}
+bool BaseChatMesh::setChannel(int idx, const mesh::GroupChannel& src) {
+  static uint8_t zeroes[] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 };
+
+  if (idx >= 0 && idx < MAX_GROUP_CHANNELS) {
+    channels[idx] = src;
+    if (memcmp(&src.secret[16], zeroes, 16) == 0) {
+      mesh::Utils::sha256(channels[idx].hash, sizeof(channels[idx].hash), src.secret, 16);  // 128-bit key
+    } else {
+      mesh::Utils::sha256(channels[idx].hash, sizeof(channels[idx].hash), src.secret, 32);  // 256-bit key
+    }
+    return true;
+  }
+  return false;
+}
+int BaseChatMesh::findChannelIdx(const mesh::GroupChannel& ch) {
+  for (int i = 0; i < MAX_GROUP_CHANNELS; i++) {
+    if (memcmp(ch.secret, channels[i].secret, sizeof(ch.secret)) == 0) return i;
+  }
+  return -1;  // not found
+}
 #else
 mesh::GroupChannel* BaseChatMesh::addChannel(const char* psk_base64) {
   return NULL;  // not supported
 }
+bool BaseChatMesh::getChannel(int idx, mesh::GroupChannel& dest) {
+  return false;
+}
+bool BaseChatMesh::setChannel(int idx, const mesh::GroupChannel& src) {
+  return false;
+}
+int BaseChatMesh::findChannelIdx(const mesh::GroupChannel& ch) {
+  return -1;  // not found
+}
 #endif
 
 ContactsIterator BaseChatMesh::startContactsIterator() {
diff --git a/src/helpers/BaseChatMesh.h b/src/helpers/BaseChatMesh.h
index 0f2e0283..c5b60dd1 100644
--- a/src/helpers/BaseChatMesh.h
+++ b/src/helpers/BaseChatMesh.h
@@ -75,7 +75,7 @@ class BaseChatMesh : public mesh::Mesh {
   unsigned long txt_send_timeout;
 #ifdef MAX_GROUP_CHANNELS
   mesh::GroupChannel channels[MAX_GROUP_CHANNELS];
-  int num_channels;
+  int num_channels;  // only for addChannel()
 #endif
   mesh::Packet* _pendingLoopback;
   uint8_t temp_buf[MAX_TRANS_UNIT];
@@ -89,6 +89,7 @@ protected:
   { 
     num_contacts = 0;
   #ifdef MAX_GROUP_CHANNELS
+    memset(channels, 0, sizeof(channels));
     num_channels = 0;
   #endif
     txt_send_timeout = 0;
@@ -152,6 +153,9 @@ public:
   int getNumContacts() const { return num_contacts; }
   ContactsIterator startContactsIterator();
   mesh::GroupChannel* addChannel(const char* psk_base64);
+  bool getChannel(int idx, mesh::GroupChannel& dest);
+  bool setChannel(int idx, const mesh::GroupChannel& src);
+  int findChannelIdx(const mesh::GroupChannel& ch);
 
   void loop();
 };