* support for GroupChannels in BaseChatMesh, and terminal chat

examples/simple_secure_chat/main.cpp

@@ -45,6 +45,7 @@
 #define DIRECT_SEND_PERHOP_FACTOR         4.0f
 #define DIRECT_SEND_PERHOP_EXTRA_MILLIS   200
 
+#define  PUBLIC_GROUP_PSK  "izOH6cXN6mrJ5e26oRXNcg=="
 
 #if defined(HELTEC_LORA_V3)
   #include <helpers/HeltecV3Board.h>
@@ -74,6 +75,7 @@ static int curr_contact_idx = 0;
 class MyMesh : public BaseChatMesh, ContactVisitor {
   FILESYSTEM* _fs;
   uint32_t expected_ack_crc;
+  mesh::GroupChannel* _public;
   unsigned long last_msg_sent;
   ContactInfo* curr_recipient;
   char command[MAX_TEXT_LEN+1];
@@ -191,6 +193,15 @@ protected:
     }
   }
 
+  void onChannelMessageRecv(const mesh::GroupChannel& channel, int in_path_len, uint32_t timestamp, const char *text) override {
+    if (in_path_len < 0) {
+      Serial.printf("PUBLIC CHANNEL MSG -> (Direct!)\n");
+    } else {
+      Serial.printf("PUBLIC CHANNEL MSG -> (Flood) hops %d\n", in_path_len);
+    }
+    Serial.printf("   %s\n", text);
+  }
+
   uint32_t calcFloodTimeoutMillisFor(uint32_t pkt_airtime_millis) const override {
     return SEND_TIMEOUT_BASE_MILLIS + (FLOOD_SEND_TIMEOUT_FACTOR * pkt_airtime_millis);
   }
@@ -226,6 +237,7 @@ public:
     }
 
     loadContacts();
+    _public = addChannel(PUBLIC_GROUP_PSK); // pre-configure Andy's public channel
   }
 
   void showWelcome() {
@@ -261,6 +273,23 @@ public:
       } else {
         Serial.println("   ERROR: no recipient selected (use 'to' cmd).");
       }
+    } else if (memcmp(command, "public ", 7) == 0) {  // send GroupChannel msg
+      uint8_t temp[5+MAX_TEXT_LEN+32];
+      uint32_t timestamp = getRTCClock()->getCurrentTime();
+      memcpy(temp, &timestamp, 4);   // mostly an extra blob to help make packet_hash unique
+      temp[4] = 0;  // attempt and flags
+
+      sprintf((char *) &temp[5], "%s: %s", self_name, &command[7]);  // <sender>: <msg>
+      temp[5 + MAX_TEXT_LEN] = 0;  // truncate if too long
+
+      int len = strlen((char *) &temp[5]);
+      auto pkt = createGroupDatagram(PAYLOAD_TYPE_GRP_TXT, *_public, temp, 5 + len);
+      if (pkt) {
+        sendFlood(pkt);
+        Serial.println("   Sent.");
+      } else {
+        Serial.println("   ERROR: unable to send");
+      }
     } else if (memcmp(command, "list", 4) == 0) {  // show Contact list, by most recent
       int n = 0;
       if (command[4] == ' ') {  // optional param, last 'N'
@@ -313,6 +342,7 @@ public:
       Serial.println("   send <text>");
       Serial.println("   advert");
       Serial.println("   reset path");
+      Serial.println("   public <text>");
     } else {
       Serial.print("   ERROR: unknown command: "); Serial.println(command);
     }

platformio.ini

@@ -96,12 +96,14 @@ extends = Heltec_lora32_v3
 build_flags =
   ${Heltec_lora32_v3.build_flags} 
   -D MAX_CONTACTS=100
+  -D MAX_CHANNELS=1
 ;  -D MESH_PACKET_LOGGING=1
 ;  -D MESH_DEBUG=1
 build_src_filter = ${Heltec_lora32_v3.build_src_filter} +<../examples/simple_secure_chat/main.cpp>
 lib_deps =
   ${Heltec_lora32_v3.lib_deps}
   adafruit/RTClib @ ^2.1.3
+  densaugeo/base64 @ ~1.4.0
 
 [env:Heltec_v3_test_admin]
 extends = Heltec_lora32_v3
@@ -261,9 +263,11 @@ extends = rak4631
 build_flags =
   ${rak4631.build_flags} 
   -D MAX_CONTACTS=100
+  -D MAX_CHANNELS=1
   -D MESH_PACKET_LOGGING=1
   -D MESH_DEBUG=1
 build_src_filter = ${rak4631.build_src_filter} +<../examples/simple_secure_chat/main.cpp>
 lib_deps =
   ${rak4631.lib_deps}
+  densaugeo/base64 @ ~1.4.0
   adafruit/RTClib @ ^2.1.3

src/helpers/BaseChatMesh.cpp

@@ -1,4 +1,6 @@
 #include <helpers/BaseChatMesh.h>
+#include <base64.hpp>
+#include <Utils.h>
 
 mesh::Packet* BaseChatMesh::createSelfAdvert(const char* name) {
   uint8_t app_data[MAX_ADVERT_DATA_SIZE];
@@ -150,6 +152,30 @@ void BaseChatMesh::onAckRecv(mesh::Packet* packet, uint32_t ack_crc) {
   }
 }
 
+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++) {
+    if (channels[i].hash[0] == hash[0]) {
+      dest[n++] = channels[i];
+    }
+  }
+  return n;
+}
+
+void BaseChatMesh::onGroupDataRecv(mesh::Packet* packet, uint8_t type, const mesh::GroupChannel& channel, uint8_t* data, size_t len) {
+  uint8_t txt_type = data[4];
+  if (type == PAYLOAD_TYPE_GRP_TXT && len > 5 && (txt_type >> 2) == 0) {  // 0 = plain text msg
+    uint32_t timestamp;
+    memcpy(&timestamp, data, 4);
+
+    // len can be > original length, but 'text' will be padded with zeroes
+    data[len] = 0; // need to make a C string again, with null terminator
+
+    // notify UI  of this new message
+    onChannelMessageRecv(channel, packet->isRouteFlood() ? packet->path_len : -1, timestamp, (const char *) &data[5]);  // let UI know
+  }
+}
+
 mesh::Packet* BaseChatMesh::composeMsgPacket(const ContactInfo& recipient, uint8_t attempt, const char *text, uint32_t& expected_ack) {
   int text_len = strlen(text);
   if (text_len > MAX_TEXT_LEN) return NULL;
@@ -240,6 +266,21 @@ bool BaseChatMesh::addContact(const ContactInfo& contact) {
   return false;
 }
 
+mesh::GroupChannel* BaseChatMesh::addChannel(const char* psk_base64) {
+  if (num_channels < MAX_CHANNELS) {
+    auto dest = &channels[num_channels];
+
+    memset(dest->secret, 0, sizeof(dest->secret));
+    int len = decode_base64((unsigned char *) psk_base64, strlen(psk_base64), dest->secret);
+    if (len == 32 || len == 16) {
+      mesh::Utils::sha256(dest->hash, sizeof(dest->hash), dest->secret, len);
+      num_channels++;
+      return dest;
+    }
+  }
+  return NULL;
+}
+
 bool ContactsIterator::hasNext(const BaseChatMesh* mesh, ContactInfo& dest) {
   if (next_idx >= mesh->num_contacts) return false;
 

src/helpers/BaseChatMesh.h

@@ -48,6 +48,8 @@ class BaseChatMesh : public mesh::Mesh {
   int sort_array[MAX_CONTACTS];
   int matching_peer_indexes[MAX_SEARCH_RESULTS];
   unsigned long txt_send_timeout;
+  mesh::GroupChannel channels[MAX_CHANNELS];
+  int num_channels;
 
   mesh::Packet* composeMsgPacket(const ContactInfo& recipient, uint8_t attempt, const char *text, uint32_t& expected_ack);
 
@@ -56,6 +58,7 @@ protected:
       : mesh::Mesh(radio, ms, rng, rtc, mgr, tables)
   { 
     num_contacts = 0;
+    num_channels = 0;
     txt_send_timeout = 0;
   }
 
@@ -67,6 +70,7 @@ protected:
   virtual uint32_t calcFloodTimeoutMillisFor(uint32_t pkt_airtime_millis) const = 0;
   virtual uint32_t calcDirectTimeoutMillisFor(uint32_t pkt_airtime_millis, uint8_t path_len) const = 0;
   virtual void onSendTimeout() = 0;
+  virtual void onChannelMessageRecv(const mesh::GroupChannel& channel, int in_path_len, uint32_t timestamp, const char *text) = 0;
 
   // Mesh overrides
   void onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) override;
@@ -75,6 +79,8 @@ protected:
   void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) override;
   bool onPeerPathRecv(mesh::Packet* packet, int sender_idx, const uint8_t* secret, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override;
   void onAckRecv(mesh::Packet* packet, uint32_t ack_crc) override;
+  int searchChannelsByHash(const uint8_t* hash, mesh::GroupChannel channels[], int max_matches) override;
+  void onGroupDataRecv(mesh::Packet* packet, uint8_t type, const mesh::GroupChannel& channel, uint8_t* data, size_t len) override;
 
 public:
   mesh::Packet* createSelfAdvert(const char* name);
@@ -83,6 +89,7 @@ public:
   void scanRecentContacts(int last_n, ContactVisitor* visitor);
   ContactInfo* searchContactsByPrefix(const char* name_prefix);
   bool  addContact(const ContactInfo& contact);
+  mesh::GroupChannel* addChannel(const char* psk_base64);
 
   void loop();
 };