mirror of
https://github.com/meshcore-dev/MeshCore.git
synced 2026-03-30 21:25:46 +00:00
103 lines
3.0 KiB
C++
103 lines
3.0 KiB
C++
#include "SerialBridge.h"
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#include <HardwareSerial.h>
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#ifdef BRIDGE_OVER_SERIAL
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// Fletcher-16
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// https://en.wikipedia.org/wiki/Fletcher%27s_checksum
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inline static uint16_t fletcher16(const uint8_t *bytes, const size_t len) {
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uint8_t sum1 = 0, sum2 = 0;
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for (size_t i = 0; i < len; i++) {
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sum1 = (sum1 + bytes[i]) % 255;
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sum2 = (sum2 + sum1) % 255;
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}
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return (sum2 << 8) | sum1;
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};
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SerialBridge::SerialBridge(Stream& serial, mesh::PacketManager* mgr) : _serial(&serial), _mgr(mgr) {}
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void SerialBridge::begin() {
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#if defined(ESP32)
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((HardwareSerial*)_serial)->setPins(BRIDGE_OVER_SERIAL_RX, BRIDGE_OVER_SERIAL_TX);
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#elif defined(RP2040_PLATFORM)
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((HardwareSerial*)_serial)->setRX(BRIDGE_OVER_SERIAL_RX);
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((HardwareSerial*)_serial)->setTX(BRIDGE_OVER_SERIAL_TX);
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#elif defined(STM32_PLATFORM)
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((HardwareSerial*)_serial)->setRx(BRIDGE_OVER_SERIAL_RX);
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((HardwareSerial*)_serial)->setTx(BRIDGE_OVER_SERIAL_TX);
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#else
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#error SerialBridge was not tested on the current platform
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#endif
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((HardwareSerial*)_serial)->begin(115200);
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}
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void SerialBridge::onPacketTransmitted(mesh::Packet* packet) {
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if (!_seen_packets.hasSeen(packet)) {
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uint8_t buffer[MAX_SERIAL_PACKET_SIZE];
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uint16_t len = packet->writeTo(buffer + 4);
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buffer[0] = (SERIAL_PKT_MAGIC >> 8) & 0xFF;
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buffer[1] = SERIAL_PKT_MAGIC & 0xFF;
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buffer[2] = (len >> 8) & 0xFF;
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buffer[3] = len & 0xFF;
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uint16_t checksum = fletcher16(buffer + 4, len);
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buffer[4 + len] = (checksum >> 8) & 0xFF;
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buffer[5 + len] = checksum & 0xFF;
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_serial->write(buffer, len + SERIAL_OVERHEAD);
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}
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}
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void SerialBridge::loop() {
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while (_serial->available()) {
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uint8_t b = _serial->read();
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if (_rx_buffer_pos < 2) {
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// Waiting for magic word
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if ((_rx_buffer_pos == 0 && b == ((SERIAL_PKT_MAGIC >> 8) & 0xFF)) ||
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(_rx_buffer_pos == 1 && b == (SERIAL_PKT_MAGIC & 0xFF))) {
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_rx_buffer[_rx_buffer_pos++] = b;
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} else {
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_rx_buffer_pos = 0;
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}
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} else {
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// Reading length, payload, and checksum
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_rx_buffer[_rx_buffer_pos++] = b;
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if (_rx_buffer_pos >= 4) {
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uint16_t len = (_rx_buffer[2] << 8) | _rx_buffer[3];
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if (len > MAX_PACKET_PAYLOAD) {
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_rx_buffer_pos = 0; // Invalid length, reset
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return;
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}
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if (_rx_buffer_pos == len + SERIAL_OVERHEAD) { // Full packet received
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uint16_t checksum = (_rx_buffer[4 + len] << 8) | _rx_buffer[5 + len];
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if (checksum == fletcher16(_rx_buffer + 4, len)) {
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mesh::Packet *pkt = _mgr->allocNew();
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if (pkt) {
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memcpy(pkt->payload, _rx_buffer + 4, len);
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pkt->payload_len = len;
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onPacketReceived(pkt);
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}
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}
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_rx_buffer_pos = 0; // Reset for next packet
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}
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}
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}
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}
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}
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void SerialBridge::onPacketReceived(mesh::Packet* packet) {
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if (!_seen_packets.hasSeen(packet)) {
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_mgr->queueInbound(packet, 0);
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} else {
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_mgr->free(packet);
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}
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}
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#endif
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