mirror of
https://github.com/meshcore-dev/MeshCore.git
synced 2026-03-30 21:25:46 +00:00
* simple_secure_chat now with a proper CLI
* new: BaseChatMesh class, for abstract chat client
This commit is contained in:
Scott Powell
258
src/helpers/BaseChatMesh.cpp
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258
src/helpers/BaseChatMesh.cpp
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#include <helpers/BaseChatMesh.h>
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mesh::Packet* BaseChatMesh::createSelfAdvert(const char* name) {
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uint8_t app_data[MAX_ADVERT_DATA_SIZE];
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uint8_t app_data_len;
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{
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AdvertDataBuilder builder(ADV_TYPE_CHAT, name);
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app_data_len = builder.encodeTo(app_data);
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}
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return createAdvert(self_id, app_data, app_data_len);
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}
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void BaseChatMesh::onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) {
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AdvertDataParser parser(app_data, app_data_len);
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if (!(parser.isValid() && parser.hasName())) {
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MESH_DEBUG_PRINTLN("onAdvertRecv: invalid app_data, or name is missing: len=%d", app_data_len);
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return;
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}
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ContactInfo* from = NULL;
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for (int i = 0; i < num_contacts; i++) {
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if (id.matches(contacts[i].id)) { // is from one of our contacts
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from = &contacts[i];
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if (timestamp <= from->last_advert_timestamp) { // check for replay attacks!!
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MESH_DEBUG_PRINTLN("onAdvertRecv: Possible replay attack, name: %s", from->name);
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return;
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}
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break;
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}
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}
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bool is_new = false;
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if (from == NULL) {
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is_new = true;
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if (num_contacts < MAX_CONTACTS) {
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from = &contacts[num_contacts++];
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from->id = id;
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from->out_path_len = -1; // initially out_path is unknown
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// only need to calculate the shared_secret once, for better performance
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self_id.calcSharedSecret(from->shared_secret, id);
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} else {
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MESH_DEBUG_PRINTLN("onAdvertRecv: contacts table is full!");
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return;
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}
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}
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// update
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strncpy(from->name, parser.getName(), sizeof(from->name)-1);
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from->name[sizeof(from->name)-1] = 0;
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from->type = parser.getType();
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from->last_advert_timestamp = timestamp;
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onDiscoveredContact(*from, is_new); // let UI know
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}
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int BaseChatMesh::searchPeersByHash(const uint8_t* hash) {
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int n = 0;
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for (int i = 0; i < num_contacts && n < MAX_SEARCH_RESULTS; i++) {
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if (contacts[i].id.isHashMatch(hash)) {
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matching_peer_indexes[n++] = i; // store the INDEXES of matching contacts (for subsequent 'peer' methods)
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}
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}
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return n;
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}
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void BaseChatMesh::getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) {
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int i = matching_peer_indexes[peer_idx];
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if (i >= 0 && i < num_contacts) {
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// lookup pre-calculated shared_secret
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memcpy(dest_secret, contacts[i].shared_secret, PUB_KEY_SIZE);
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} else {
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MESH_DEBUG_PRINTLN("getPeerSharedSecret: Invalid peer idx: %d", i);
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}
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}
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void BaseChatMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) {
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if (type == PAYLOAD_TYPE_TXT_MSG && len > 5) {
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int i = matching_peer_indexes[sender_idx];
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if (i < 0 || i >= num_contacts) {
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MESH_DEBUG_PRINTLN("onPeerDataRecv: Invalid sender idx: %d", i);
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return;
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}
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ContactInfo& from = contacts[i];
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uint32_t timestamp;
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memcpy(×tamp, data, 4); // timestamp (by sender's RTC clock - which could be wrong)
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uint flags = data[4]; // message attempt number, and other flags
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// len can be > original length, but 'text' will be padded with zeroes
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data[len] = 0; // need to make a C string again, with null terminator
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//if ( ! alreadyReceived timestamp ) {
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if ((flags >> 2) == 0) { // plain text msg?
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onMessageRecv(from, packet->isRouteFlood(), timestamp, (const char *) &data[5]); // let UI know
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uint32_t ack_hash; // calc truncated hash of the message timestamp + text + sender pub_key, to prove to sender that we got it
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mesh::Utils::sha256((uint8_t *) &ack_hash, 4, data, 5 + strlen((char *)&data[5]), from.id.pub_key, PUB_KEY_SIZE);
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if (packet->isRouteFlood()) {
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// let this sender know path TO here, so they can use sendDirect(), and ALSO encode the ACK
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mesh::Packet* path = createPathReturn(from.id, secret, packet->path, packet->path_len,
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PAYLOAD_TYPE_ACK, (uint8_t *) &ack_hash, 4);
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if (path) sendFlood(path);
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} else {
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mesh::Packet* ack = createAck(ack_hash);
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if (ack) {
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if (from.out_path_len < 0) {
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sendFlood(ack);
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} else {
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sendDirect(ack, from.out_path, from.out_path_len);
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}
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}
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}
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} else {
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MESH_DEBUG_PRINTLN("onPeerDataRecv: unsupported message type: %u", (uint32_t) (flags >> 2));
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}
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}
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}
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bool BaseChatMesh::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) {
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int i = matching_peer_indexes[sender_idx];
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if (i < 0 || i >= num_contacts) {
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MESH_DEBUG_PRINTLN("onPeerPathRecv: Invalid sender idx: %d", i);
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return false;
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}
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ContactInfo& from = contacts[i];
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// NOTE: for this impl, we just replace the current 'out_path' regardless, whenever sender sends us a new out_path.
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// FUTURE: could store multiple out_paths per contact, and try to find which is the 'best'(?)
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memcpy(from.out_path, path, from.out_path_len = path_len); // store a copy of path, for sendDirect()
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onContactPathUpdated(from);
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if (extra_type == PAYLOAD_TYPE_ACK && extra_len >= 4) {
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// also got an encoded ACK!
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if (processAck(extra)) {
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txt_send_timeout = 0; // matched one we're waiting for, cancel timeout timer
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}
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}
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return true; // send reciprocal path if necessary
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}
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void BaseChatMesh::onAckRecv(mesh::Packet* packet, uint32_t ack_crc) {
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if (processAck((uint8_t *)&ack_crc)) {
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txt_send_timeout = 0; // matched one we're waiting for, cancel timeout timer
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packet->markDoNotRetransmit(); // ACK was for this node, so don't retransmit
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}
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}
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mesh::Packet* BaseChatMesh::composeMsgPacket(const ContactInfo& recipient, uint8_t attempt, const char *text, uint32_t& expected_ack) {
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int text_len = strlen(text);
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if (text_len > MAX_TEXT_LEN) return NULL;
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uint8_t temp[5+MAX_TEXT_LEN+1];
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uint32_t timestamp = getRTCClock()->getCurrentTime();
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memcpy(temp, ×tamp, 4); // mostly an extra blob to help make packet_hash unique
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temp[4] = (attempt & 3);
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memcpy(&temp[5], text, text_len + 1);
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// calc expected ACK reply
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mesh::Utils::sha256((uint8_t *)&expected_ack, 4, temp, 5 + text_len, self_id.pub_key, PUB_KEY_SIZE);
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return createDatagram(PAYLOAD_TYPE_TXT_MSG, recipient.id, recipient.shared_secret, temp, 5 + text_len);
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}
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int BaseChatMesh::sendMessage(const ContactInfo& recipient, uint8_t attempt, const char* text, uint32_t& expected_ack) {
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mesh::Packet* pkt = composeMsgPacket(recipient, attempt, text, expected_ack);
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if (pkt == NULL) return MSG_SEND_FAILED;
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uint32_t t = _radio->getEstAirtimeFor(pkt->payload_len + pkt->path_len + 2);
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int rc;
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if (recipient.out_path_len < 0) {
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sendFlood(pkt);
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txt_send_timeout = futureMillis(calcFloodTimeoutMillisFor(t));
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rc = MSG_SEND_SENT_FLOOD;
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} else {
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sendDirect(pkt, recipient.out_path, recipient.out_path_len);
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txt_send_timeout = futureMillis(calcDirectTimeoutMillisFor(t, recipient.out_path_len));
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rc = MSG_SEND_SENT_DIRECT;
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}
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return rc;
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}
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void BaseChatMesh::resetPathTo(ContactInfo& recipient) {
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if (recipient.out_path_len >= 0) {
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recipient.out_path_len = -1;
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}
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}
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static ContactInfo* table; // pass via global :-(
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static int cmp_adv_timestamp(const void *a, const void *b) {
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int a_idx = *((int *)a);
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int b_idx = *((int *)b);
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if (table[b_idx].last_advert_timestamp > table[a_idx].last_advert_timestamp) return 1;
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if (table[b_idx].last_advert_timestamp < table[a_idx].last_advert_timestamp) return -1;
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return 0;
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}
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void BaseChatMesh::scanRecentContacts(int last_n, ContactVisitor* visitor) {
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for (int i = 0; i < num_contacts; i++) { // sort the INDEXES into contacts[]
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sort_array[i] = i;
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}
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table = contacts; // pass via global *sigh* :-(
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qsort(sort_array, num_contacts, sizeof(sort_array[0]), cmp_adv_timestamp);
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if (last_n == 0) {
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last_n = num_contacts; // scan ALL
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} else {
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if (last_n > num_contacts) last_n = num_contacts;
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}
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for (int i = 0; i < last_n; i++) {
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visitor->onContactVisit(contacts[sort_array[i]]);
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}
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}
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ContactInfo* BaseChatMesh::searchContactsByPrefix(const char* name_prefix) {
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int len = strlen(name_prefix);
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for (int i = 0; i < num_contacts; i++) {
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auto c = &contacts[i];
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if (memcmp(c->name, name_prefix, len) == 0) return c;
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}
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return NULL; // not found
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}
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bool BaseChatMesh::addContact(const ContactInfo& contact) {
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if (num_contacts < MAX_CONTACTS) {
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auto dest = &contacts[num_contacts++];
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*dest = contact;
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// calc the ECDH shared secret (just once for performance)
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self_id.calcSharedSecret(dest->shared_secret, contact.id);
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return true; // success
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}
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return false;
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}
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bool ContactsIterator::hasNext(const BaseChatMesh* mesh, ContactInfo& dest) {
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if (next_idx >= mesh->num_contacts) return false;
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dest = mesh->contacts[next_idx++];
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return true;
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}
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void BaseChatMesh::loop() {
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Mesh::loop();
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if (txt_send_timeout && millisHasNowPassed(txt_send_timeout)) {
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// failed to get an ACK
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onSendTimeout();
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txt_send_timeout = 0;
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}
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}
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