#include "module_ax25_decoder.h" #include "common/utils.h" #include "imgui/imgui.h" #include "logger.h" #include "common/codings/deframing/hdlc_def.h" #include "common/codings/differential/nrzi.h" #include "common/codings/lfsr.h" #include namespace ax25 { AX25DecoderModule::AX25DecoderModule(std::string input_file, std::string output_file_hint, nlohmann::json parameters) : satdump::pipeline::base::FileStreamToFileStreamModule(input_file, output_file_hint, parameters) { input_buffer = new int8_t[256]; d_nrzi = parameters.contains("nrzi") ? parameters["nrzi"].get() : false; d_g3ruh = parameters.contains("g3ruh") ? parameters["g3ruh"].get() : false; fsfsm_file_ext = ".frm"; } AX25DecoderModule::~AX25DecoderModule() { delete[] input_buffer; } void AX25DecoderModule::process() { diff::NRZIDiff nrzi_decoder; common::lfsr g3rhu_descramble(0x21, 0x0, 16); HDLCDeframer hdlc_deframer(d_parameters["min_sz"].get(), d_parameters["max_sz"].get()); uint8_t bits_buf[256]; while (should_run()) { // Read buffer read_data((uint8_t *)input_buffer, 256); // Slice for (int i = 0; i < 256; i++) bits_buf[i] = input_buffer[i] > 0; // Optional NRZ-I if (d_nrzi) nrzi_decoder.decode_bits(bits_buf, 256); // Optional G3RUH for (int i = 0; i < 256; i++) bits_buf[i] = g3rhu_descramble.next_bit_descramble(bits_buf[i]); // Deframe auto frames = hdlc_deframer.work(bits_buf, 256); for (auto frm : frames) { std::string source_callsign; for (int i = 0; i < 6; i++) source_callsign += frm[i] >> 1; std::string destination_callsign; for (int i = 7; i < 7 + 6; i++) destination_callsign += frm[i] >> 1; int source_ssid = frm[6] >> 1; int target_ssid = frm[7 + 6] >> 1; int ctrl = frm[14]; int pid = frm[15]; logger->trace("AX.25 Frame - SRC : " + source_callsign + ",%d DST : " + destination_callsign + ",%d CTRL : %d PID : %d", source_ssid, target_ssid, ctrl, pid); // Add a custom header to ease up forwarding to the next stuff uint16_t pkt_sz = frm.size(); uint8_t buffer_sz[6]; buffer_sz[0] = 0x1a; buffer_sz[1] = 0xcf; buffer_sz[2] = 0xfc; buffer_sz[3] = 0x1d; buffer_sz[4] = pkt_sz >> 8; buffer_sz[5] = pkt_sz & 0xFF; frm.insert(frm.begin(), buffer_sz, buffer_sz + 6); write_data((uint8_t *)frm.data(), frm.size()); frm_cnt++; } } logger->info("Decoding finished"); cleanup(); } nlohmann::json AX25DecoderModule::getModuleStats() { auto v = satdump::pipeline::base::FileStreamToFileStreamModule::getModuleStats(); v["frm_cnt"] = frm_cnt; return v; } void AX25DecoderModule::drawUI(bool window) { ImGui::Begin("AX-25 Decoder", NULL, window ? 0 : NOWINDOW_FLAGS); ImGui::Button("Deframer", {200 * ui_scale, 20 * ui_scale}); { ImGui::Text("Frames : "); ImGui::SameLine(); ImGui::TextColored(style::theme.green, UITO_C_STR(frm_cnt)); } drawProgressBar(); ImGui::End(); } std::string AX25DecoderModule::getID() { return "ax25_decoder"; } std::shared_ptr AX25DecoderModule::getInstance(std::string input_file, std::string output_file_hint, nlohmann::json parameters) { return std::make_shared(input_file, output_file_hint, parameters); } } // namespace ax25