feat: Add support for PAYLOAD_TYPE_GRP_DATA

Docs changes are to reflect how it is currently in fw

This adds ability to send datagram data to everyone in channel

src/helpers/BaseChatMesh.cpp

@@ -353,8 +353,10 @@ int BaseChatMesh::searchChannelsByHash(const uint8_t* hash, mesh::GroupChannel d
 #endif
 
 void BaseChatMesh::onGroupDataRecv(mesh::Packet* packet, uint8_t type, const mesh::GroupChannel& channel, uint8_t* data, size_t len) {
+  if (len < 5) return;
+
   uint8_t txt_type = data[4];
-  if (type == PAYLOAD_TYPE_GRP_TXT && len > 5 && (txt_type >> 2) == 0) {  // 0 = plain text msg
+  if (type == PAYLOAD_TYPE_GRP_TXT && (txt_type >> 2) == 0) {  // 0 = plain text msg
     uint32_t timestamp;
     memcpy(&timestamp, data, 4);
 
@@ -363,6 +365,10 @@ void BaseChatMesh::onGroupDataRecv(mesh::Packet* packet, uint8_t type, const mes
 
     // notify UI  of this new message
     onChannelMessageRecv(channel, packet, timestamp, (const char *) &data[5]);  // let UI know
+  } else if (type == PAYLOAD_TYPE_GRP_DATA) {
+    uint32_t timestamp;
+    memcpy(&timestamp, data, 4);
+    onChannelDataRecv(channel, packet, timestamp, txt_type, &data[5], len - 5);
   }
 }
 
@@ -454,6 +460,26 @@ bool BaseChatMesh::sendGroupMessage(uint32_t timestamp, mesh::GroupChannel& chan
   return false;
 }
 
+bool BaseChatMesh::sendGroupData(uint32_t timestamp, mesh::GroupChannel& channel, uint8_t txt_type, const uint8_t* data, int data_len) {
+  if (data_len < 0) return false;
+  // createGroupDatagram() accepts at most (MAX_PACKET_PAYLOAD - CIPHER_BLOCK_SIZE)
+  // plaintext bytes; subtract our 5-byte {timestamp, txt_type} header.
+  const int max_group_data_len = (MAX_PACKET_PAYLOAD - CIPHER_BLOCK_SIZE) - 5;
+  if (data_len > max_group_data_len) data_len = max_group_data_len;
+
+  uint8_t temp[MAX_PACKET_PAYLOAD];
+  memcpy(temp, &timestamp, 4);
+  temp[4] = txt_type;
+  if (data_len > 0) memcpy(&temp[5], data, data_len);
+
+  auto pkt = createGroupDatagram(PAYLOAD_TYPE_GRP_DATA, channel, temp, 5 + data_len);
+  if (pkt) {
+    sendFloodScoped(channel, pkt);
+    return true;
+  }
+  return false;
+}
+
 bool BaseChatMesh::shareContactZeroHop(const ContactInfo& contact) {
   int plen = getBlobByKey(contact.id.pub_key, PUB_KEY_SIZE, temp_buf);  // retrieve last raw advert packet
   if (plen == 0) return false;  // not found

src/helpers/BaseChatMesh.h

@@ -111,6 +111,8 @@ protected:
   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, mesh::Packet* pkt, uint32_t timestamp, const char *text) = 0;
+  virtual void onChannelDataRecv(const mesh::GroupChannel& channel, mesh::Packet* pkt, uint32_t timestamp, uint8_t txt_type,
+                                 const uint8_t* data, size_t data_len) {}
   virtual uint8_t onContactRequest(const ContactInfo& contact, uint32_t sender_timestamp, const uint8_t* data, uint8_t len, uint8_t* reply) = 0;
   virtual void onContactResponse(const ContactInfo& contact, const uint8_t* data, uint8_t len) = 0;
   virtual void handleReturnPathRetry(const ContactInfo& contact, const uint8_t* path, uint8_t path_len);
@@ -148,6 +150,7 @@ public:
   int  sendMessage(const ContactInfo& recipient, uint32_t timestamp, uint8_t attempt, const char* text, uint32_t& expected_ack, uint32_t& est_timeout);
   int  sendCommandData(const ContactInfo& recipient, uint32_t timestamp, uint8_t attempt, const char* text, uint32_t& est_timeout);
   bool sendGroupMessage(uint32_t timestamp, mesh::GroupChannel& channel, const char* sender_name, const char* text, int text_len);
+  bool sendGroupData(uint32_t timestamp, mesh::GroupChannel& channel, uint8_t txt_type, const uint8_t* data, int data_len);
   int  sendLogin(const ContactInfo& recipient, const char* password, uint32_t& est_timeout);
   int  sendAnonReq(const ContactInfo& recipient, const uint8_t* data, uint8_t len, uint32_t& tag, uint32_t& est_timeout);
   int  sendRequest(const ContactInfo& recipient, uint8_t req_type, uint32_t& tag, uint32_t& est_timeout);

src/helpers/TxtDataHelpers.h

@@ -6,6 +6,7 @@
 #define TXT_TYPE_PLAIN          0    // a plain text message
 #define TXT_TYPE_CLI_DATA       1    // a CLI command
 #define TXT_TYPE_SIGNED_PLAIN   2    // plain text, signed by sender
+#define TXT_TYPE_CUSTOM_BINARY  0xFF // custom app binary payload (group/channel datagrams)
 
 class StrHelper {
 public: