#include // needed for PlatformIO #include #if defined(NRF52_PLATFORM) #include #elif defined(ESP32) #include #endif #define RADIOLIB_STATIC_ONLY 1 #include #include #include #include #include #include #include #include /* ------------------------------ Config -------------------------------- */ #define FIRMWARE_VER_TEXT "v1 (build: 24 Jan 2025)" #ifndef LORA_FREQ #define LORA_FREQ 915.0 #endif #ifndef LORA_BW #define LORA_BW 250 #endif #ifndef LORA_SF #define LORA_SF 10 #endif #ifndef LORA_CR #define LORA_CR 5 #endif #ifndef LORA_TX_POWER #define LORA_TX_POWER 20 #endif #ifndef ADVERT_NAME #define ADVERT_NAME "Test BBS" #endif #ifndef ADVERT_LAT #define ADVERT_LAT 0.0 #endif #ifndef ADVERT_LON #define ADVERT_LON 0.0 #endif #ifndef ADMIN_PASSWORD #define ADMIN_PASSWORD "password" #endif #ifndef MAX_CLIENTS #define MAX_CLIENTS 32 #endif #ifndef MAX_UNSYNCED_POSTS #define MAX_UNSYNCED_POSTS 16 #endif #if defined(HELTEC_LORA_V3) #include #include static HeltecV3Board board; #elif defined(ARDUINO_XIAO_ESP32C3) #include #include #include static XiaoC3Board board; #elif defined(SEEED_XIAO_S3) #include #include static ESP32Board board; #elif defined(RAK_4631) #include #include static RAK4631Board board; #else #error "need to provide a 'board' object" #endif /* ------------------------------ Code -------------------------------- */ struct ClientInfo { mesh::Identity id; uint32_t last_timestamp; // by THEIR clock uint32_t last_activity; // by OUR clock uint32_t sync_since; // sync messages SINCE this timestamp (by OUR clock) uint32_t pending_ack; uint32_t push_post_timestamp; unsigned long ack_timeout; bool is_admin; uint8_t push_failures; uint8_t secret[PUB_KEY_SIZE]; int out_path_len; uint8_t out_path[MAX_PATH_SIZE]; }; #define MAX_POST_TEXT_LEN (160-9) struct PostInfo { mesh::Identity author; uint32_t post_timestamp; // by OUR clock char text[MAX_POST_TEXT_LEN+1]; }; #define REPLY_DELAY_MILLIS 1500 #define PUSH_NOTIFY_DELAY_MILLIS 1000 #define SYNC_PUSH_INTERVAL 1000 #define PUSH_ACK_TIMEOUT_FLOOD 12000 #define PUSH_TIMEOUT_BASE 4000 #define PUSH_ACK_TIMEOUT_FACTOR 2000 class MyMesh : public mesh::Mesh { RadioLibWrapper* my_radio; float airtime_factor; uint8_t reply_data[MAX_PACKET_PAYLOAD]; int num_clients; ClientInfo known_clients[MAX_CLIENTS]; unsigned long next_push; int next_client_idx; // for round-robin polling int next_post_idx; PostInfo posts[MAX_UNSYNCED_POSTS]; // cyclic queue ClientInfo* putClient(const mesh::Identity& id) { for (int i = 0; i < num_clients; i++) { if (id.matches(known_clients[i].id)) return &known_clients[i]; // already known } ClientInfo* newClient; if (num_clients < MAX_CLIENTS) { newClient = &known_clients[num_clients++]; } else { // table is currently full // evict least active client uint32_t oldest_timestamp = 0xFFFFFFFF; newClient = &known_clients[0]; for (int i = 0; i < num_clients; i++) { auto c = &known_clients[i]; if (c->last_activity < oldest_timestamp) { oldest_timestamp = c->last_activity; newClient = c; } } } newClient->id = id; newClient->out_path_len = -1; // initially out_path is unknown newClient->last_timestamp = 0; self_id.calcSharedSecret(newClient->secret, id); // calc ECDH shared secret return newClient; } void evict(ClientInfo* client) { client->last_activity = 0; // this slot will now be re-used (will be oldest) memset(client->id.pub_key, 0, sizeof(client->id.pub_key)); memset(client->secret, 0, sizeof(client->secret)); client->pending_ack = 0; } void addPost(ClientInfo* client, const char* postData, char reply[]) { // TODO: suggested postData format: /<descrption> posts[next_post_idx].author = client->id; // add to cyclic queue strncpy(posts[next_post_idx].text, postData, MAX_POST_TEXT_LEN); posts[next_post_idx].text[MAX_POST_TEXT_LEN] = 0; posts[next_post_idx].post_timestamp = getRTCClock()->getCurrentTime(); // TODO: only post at maximum of ONE PER SECOND, so that post_timestamps are UNIQUE!! next_post_idx = (next_post_idx + 1) % MAX_UNSYNCED_POSTS; strcpy(reply, "[Posted]"); next_push = futureMillis(PUSH_NOTIFY_DELAY_MILLIS); } void pushPostToClient(ClientInfo* client, PostInfo& post) { int len = 0; memcpy(&reply_data[len], &post.post_timestamp, 4); len += 4; // this is a PAST timestamp... but should be accepted by client reply_data[len++] = (TXT_TYPE_SIGNED_PLAIN << 2); // 'signed' plain text // encode prefix of post.author.pub_key memcpy(&reply_data[len], post.author.pub_key, 4); len += 4; // just first 4 bytes int text_len = strlen(post.text); memcpy(&reply_data[len], post.text, text_len); len += text_len; // calc expected ACK reply mesh::Utils::sha256((uint8_t *)&client->pending_ack, 4, reply_data, len, self_id.pub_key, PUB_KEY_SIZE); client->push_post_timestamp = post.post_timestamp; auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, client->secret, reply_data, len); if (reply) { if (client->out_path_len < 0) { sendFlood(reply); client->ack_timeout = futureMillis(PUSH_ACK_TIMEOUT_FLOOD); } else { sendDirect(reply, client->out_path, client->out_path_len); client->ack_timeout = futureMillis(PUSH_TIMEOUT_BASE + PUSH_ACK_TIMEOUT_FACTOR * (client->out_path_len + 1)); } } else { client->pending_ack = 0; MESH_DEBUG_PRINTLN("Unable to push post to client"); } } bool processAck(const uint8_t *data) { for (int i = 0; i < num_clients; i++) { auto client = &known_clients[i]; if (client->pending_ack && memcmp(data, &client->pending_ack, 4) == 0) { // got an ACK from Client! client->pending_ack = 0; // clear this, so next push can happen client->push_failures = 0; client->sync_since = client->push_post_timestamp; // advance Client's SINCE timestamp, to sync next post return true; } } return false; } protected: float getAirtimeBudgetFactor() const override { return airtime_factor; } #if ROOM_IS_ALSO_REPEATER bool allowPacketForward(const mesh::Packet* packet) override { return true; // Yes, allow packet to be forwarded } #endif void onAnonDataRecv(mesh::Packet* packet, uint8_t type, const mesh::Identity& sender, uint8_t* data, size_t len) override { if (type == PAYLOAD_TYPE_ANON_REQ) { // received an initial request by a possible admin client (unknown at this stage) uint32_t sender_timestamp, sender_sync_since; memcpy(&sender_timestamp, data, 4); memcpy(&sender_sync_since, &data[4], 4); // sender's "sync messags SINCE x" timestamp bool is_admin; if (memcmp(&data[8], ADMIN_PASSWORD, strlen(ADMIN_PASSWORD)) == 0) { // check for valid admin password is_admin = true; } else { is_admin = false; #ifdef ROOM_PASSWORD if (memcmp(&data[8], ROOM_PASSWORD, strlen(ROOM_PASSWORD)) != 0) { // check the room/public password MESH_DEBUG_PRINTLN("Incorrect room password"); return; // no response. Client will timeout } #endif } auto client = putClient(sender); // add to known clients (if not already known) if (sender_timestamp <= client->last_timestamp) { MESH_DEBUG_PRINTLN("possible replay attack!"); return; } MESH_DEBUG_PRINTLN("Login success!"); client->is_admin = is_admin; client->last_timestamp = sender_timestamp; client->sync_since = sender_sync_since; client->pending_ack = 0; client->push_failures = 0; uint32_t now = getRTCClock()->getCurrentTime(); client->last_activity = now; memcpy(reply_data, &now, 4); // response packets always prefixed with timestamp // TODO: maybe reply with count of messages waiting to be synced for THIS client? memset(&reply_data[4], 0, 4); // FUTURE: reserve 4 bytes memcpy(&reply_data[8], "OK", 2); if (packet->isRouteFlood()) { // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response mesh::Packet* path = createPathReturn(sender, client->secret, packet->path, packet->path_len, PAYLOAD_TYPE_RESPONSE, reply_data, 8 + 2); if (path) sendFlood(path); } else { mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, client->secret, reply_data, 8 + 2); if (reply) { if (client->out_path_len >= 0) { // we have an out_path, so send DIRECT sendDirect(reply, client->out_path, client->out_path_len); } else { sendFlood(reply); } } } } } int matching_peer_indexes[MAX_CLIENTS]; int searchPeersByHash(const uint8_t* hash) override { int n = 0; for (int i = 0; i < num_clients; i++) { if (known_clients[i].id.isHashMatch(hash)) { matching_peer_indexes[n++] = i; // store the INDEXES of matching contacts (for subsequent 'peer' methods) } } return n; } void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override { int i = matching_peer_indexes[peer_idx]; if (i >= 0 && i < num_clients) { // lookup pre-calculated shared_secret memcpy(dest_secret, known_clients[i].secret, PUB_KEY_SIZE); } else { MESH_DEBUG_PRINTLN("getPeerSharedSecret: Invalid peer idx: %d", i); } } void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) override { int i = matching_peer_indexes[sender_idx]; if (i < 0 || i >= num_clients) { // get from our known_clients table (sender SHOULD already be known in this context) MESH_DEBUG_PRINTLN("onPeerDataRecv: invalid peer idx: %d", i); return; } auto client = &known_clients[i]; if (type == PAYLOAD_TYPE_TXT_MSG && len > 5) { // a CLI command uint32_t sender_timestamp; memcpy(&sender_timestamp, data, 4); // timestamp (by sender's RTC clock - which could be wrong) uint flags = (data[4] >> 2); // message attempt number, and other flags if (!(flags == TXT_TYPE_PLAIN || flags == TXT_TYPE_CLI_DATA)) { MESH_DEBUG_PRINTLN("onPeerDataRecv: unsupported command flags received: flags=%02x", (uint32_t)flags); } else if (sender_timestamp > client->last_timestamp) { // prevent replay attacks client->last_timestamp = sender_timestamp; uint32_t now = getRTCClock()->getCurrentTime(); client->last_activity = now; // 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 uint32_t ack_hash; // calc truncated hash of the message timestamp + text + sender pub_key, to prove to sender that we got it mesh::Utils::sha256((uint8_t *) &ack_hash, 4, data, 5 + strlen((char *)&data[5]), client->id.pub_key, PUB_KEY_SIZE); mesh::Packet* ack = createAck(ack_hash); if (ack) { if (client->out_path_len < 0) { sendFlood(ack); } else { sendDirect(ack, client->out_path, client->out_path_len); } } uint8_t temp[166]; if (flags == TXT_TYPE_CLI_DATA) { if (client->is_admin) { handleAdminCommand(sender_timestamp, (const char *) &data[5], (char *) &temp[5]); } else { strcpy((char *) &temp[5], "auth-err"); } } else { // TXT_TYPE_PLAIN addPost(client, (const char *) &data[5], (char *) &temp[5]); } int text_len = strlen((char *) &temp[5]); if (text_len > 0) { if (now == sender_timestamp) { // WORKAROUND: the two timestamps need to be different, in the CLI view now++; } memcpy(temp, &now, 4); // mostly an extra blob to help make packet_hash unique temp[4] = (TXT_TYPE_PLAIN << 2); // attempt and flags // calc expected ACK reply //mesh::Utils::sha256((uint8_t *)&expected_ack_crc, 4, temp, 5 + text_len, self_id.pub_key, PUB_KEY_SIZE); auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len); if (reply) { if (client->out_path_len < 0) { sendFlood(reply, REPLY_DELAY_MILLIS); } else { sendDirect(reply, client->out_path, client->out_path_len, REPLY_DELAY_MILLIS); } } } } else { MESH_DEBUG_PRINTLN("onPeerDataRecv: possible replay attack detected"); } } } 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 { // TODO: prevent replay attacks int i = matching_peer_indexes[sender_idx]; if (i >= 0 && i < num_clients) { // get from our known_clients table (sender SHOULD already be known in this context) MESH_DEBUG_PRINTLN("PATH to client, path_len=%d", (uint32_t) path_len); auto client = &known_clients[i]; memcpy(client->out_path, path, client->out_path_len = path_len); // store a copy of path, for sendDirect() } else { MESH_DEBUG_PRINTLN("onPeerPathRecv: invalid peer idx: %d", i); } if (extra_type == PAYLOAD_TYPE_ACK && extra_len >= 4) { // also got an encoded ACK! processAck(extra); } // NOTE: no reciprocal path send!! return false; } void onAckRecv(mesh::Packet* packet, uint32_t ack_crc) override { if (processAck((uint8_t *)&ack_crc)) { packet->markDoNotRetransmit(); // ACK was for this node, so don't retransmit } } public: MyMesh(RadioLibWrapper& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::MeshTables& tables) : mesh::Mesh(radio, ms, rng, rtc, *new StaticPoolPacketManager(32), tables) { my_radio = &radio; airtime_factor = 1.0; // one half num_clients = 0; next_post_idx = 0; next_client_idx = 0; next_push = 0; memset(posts, 0, sizeof(posts)); } void sendSelfAdvertisement() { uint8_t app_data[MAX_ADVERT_DATA_SIZE]; uint8_t app_data_len; { AdvertDataBuilder builder(ADV_TYPE_ROOM, ADVERT_NAME, ADVERT_LAT, ADVERT_LON); app_data_len = builder.encodeTo(app_data); } mesh::Packet* pkt = createAdvert(self_id, app_data, app_data_len); if (pkt) { sendFlood(pkt, 1200); // add slight delay } else { MESH_DEBUG_PRINTLN("ERROR: unable to create advertisement packet!"); } } void handleAdminCommand(uint32_t sender_timestamp, const char* command, char reply[]) { while (*command == ' ') command++; // skip leading spaces if (memcmp(command, "reboot", 6) == 0) { board.reboot(); // doesn't return } else if (memcmp(command, "advert", 6) == 0) { sendSelfAdvertisement(); strcpy(reply, "OK - Advert sent"); } else if (memcmp(command, "clock sync", 10) == 0) { uint32_t curr = getRTCClock()->getCurrentTime(); if (sender_timestamp > curr) { getRTCClock()->setCurrentTime(sender_timestamp + 1); strcpy(reply, "OK - clock set"); } else { strcpy(reply, "ERR: clock cannot go backwards"); } } else if (memcmp(command, "clock", 5) == 0) { uint32_t now = getRTCClock()->getCurrentTime(); DateTime dt = DateTime(now); sprintf(reply, "%02d:%02d - %d/%d/%d UTC", dt.hour(), dt.minute(), dt.day(), dt.month(), dt.year()); } else if (memcmp(command, "set ", 4) == 0) { if (memcmp(&command[4], "AF", 2) == 0 || memcmp(&command[4], "af=", 2) == 0) { airtime_factor = atof(&command[7]); strcpy(reply, "OK"); } else { sprintf(reply, "unknown config: %s", &command[4]); } } else if (memcmp(command, "ver", 3) == 0) { strcpy(reply, FIRMWARE_VER_TEXT); } else { strcpy(reply, "?"); // unknown command } } void loop() { mesh::Mesh::loop(); if (millisHasNowPassed(next_push) && num_clients > 0) { // check for ACK timeouts for (int i = 0; i < num_clients; i++) { auto c = &known_clients[i]; if (c->pending_ack && millisHasNowPassed(c->ack_timeout)) { c->push_failures++; c->pending_ack = 0; // reset (TODO: keep prev expected_ack's in a list, incase they arrive LATER, after we retry) MESH_DEBUG_PRINTLN("pending ACK timed out: push_failures: %d", (uint32_t)c->push_failures); if (c->push_failures >= 3) { evict(c); } } } // check next Round-Robin client, and sync next new post auto client = &known_clients[next_client_idx]; if (client->pending_ack == 0 && client->last_activity != 0) { // not already waiting for ACK, AND not evicted for (int k = 0, idx = next_post_idx; k < MAX_UNSYNCED_POSTS; k++) { if (posts[idx].post_timestamp > client->sync_since // is new post for this Client? && !posts[idx].author.matches(client->id)) { // don't push posts to the author // push this post to Client, then wait for ACK pushPostToClient(client, posts[idx]); break; } idx = (idx + 1) % MAX_UNSYNCED_POSTS; // wrap to start of cyclic queue } } next_client_idx = (next_client_idx + 1) % num_clients; // round robin polling for each client next_push = futureMillis(SYNC_PUSH_INTERVAL); } // TODO: periodically check for OLD/inactive entries in known_clients[], and evict } }; #if defined(NRF52_PLATFORM) RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, SPI); #elif defined(P_LORA_SCLK) SPIClass spi; RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi); #else RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY); #endif StdRNG fast_rng; SimpleMeshTables tables; #ifdef ESP32 ESP32RTCClock rtc_clock; #else VolatileRTCClock rtc_clock; #endif MyMesh the_mesh(*new WRAPPER_CLASS(radio, board), *new ArduinoMillis(), fast_rng, rtc_clock, tables); void halt() { while (1) ; } static char command[MAX_POST_TEXT_LEN+1]; void setup() { Serial.begin(115200); delay(1000); board.begin(); #ifdef ESP32 rtc_clock.begin(); #endif #ifdef SX126X_DIO3_TCXO_VOLTAGE float tcxo = SX126X_DIO3_TCXO_VOLTAGE; #else float tcxo = 1.6f; #endif #if defined(NRF52_PLATFORM) SPI.setPins(P_LORA_MISO, P_LORA_SCLK, P_LORA_MOSI); SPI.begin(); #elif defined(P_LORA_SCLK) spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI); #endif int status = radio.begin(LORA_FREQ, LORA_BW, LORA_SF, LORA_CR, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, LORA_TX_POWER, 8, tcxo); if (status != RADIOLIB_ERR_NONE) { delay(5000); Serial.print("ERROR: radio init failed: "); Serial.println(status); halt(); } radio.setCRC(0); #ifdef SX126X_CURRENT_LIMIT radio.setCurrentLimit(SX126X_CURRENT_LIMIT); #endif #ifdef SX126X_DIO2_AS_RF_SWITCH radio.setDio2AsRfSwitch(SX126X_DIO2_AS_RF_SWITCH); #endif #if defined(NRF52_PLATFORM) InternalFS.begin(); IdentityStore store(InternalFS, "/identity"); #elif defined(ESP32) SPIFFS.begin(true); IdentityStore store(SPIFFS, "/identity"); #else #error "need to define filesystem" #endif if (!store.load("_main", the_mesh.self_id)) { the_mesh.self_id = mesh::LocalIdentity(the_mesh.getRNG()); // create new random identity store.save("_main", the_mesh.self_id); } Serial.print("Room ID: "); mesh::Utils::printHex(Serial, the_mesh.self_id.pub_key, PUB_KEY_SIZE); Serial.println(); command[0] = 0; the_mesh.begin(); // send out initial Advertisement to the mesh the_mesh.sendSelfAdvertisement(); } void loop() { int len = strlen(command); while (Serial.available() && len < sizeof(command)-1) { char c = Serial.read(); if (c != '\n') { command[len++] = c; command[len] = 0; } Serial.print(c); } if (len == sizeof(command)-1) { // command buffer full command[sizeof(command)-1] = '\r'; } if (len > 0 && command[len - 1] == '\r') { // received complete line command[len - 1] = 0; // replace newline with C string null terminator char reply[160]; the_mesh.handleAdminCommand(0, command, reply); // NOTE: there is no sender_timestamp via serial! if (reply[0]) { Serial.print(" -> "); Serial.println(reply); } command[0] = 0; // reset command buffer } the_mesh.loop(); }