Public Access
twislaandClaude Opus 5.5
2fce79aebd
The Sniffer lists packets newest first (time, RSSI, SNR, and for Meshtastic the sender, receiver and hops), with the clear header and a hex dump on Enter (Q96); `p` picks an EU868 preset, kept in Settings (Q95). `c` starts a Capture: pcap with LoRaTap in /captures/lora, its own Clean-up category, recorded by a small Service so it carries on with the App closed (Q97, Q100). The Status Bar shows L while listening, bright on each packet, and CAP while capturing (Q101). StorageService gains raw appends for binary files. Debug Builds get `lora inject` to test all of this with no transmitter in range: a Capture made on the device reads back in TShark field for field. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT
65 lines
2.4 KiB
C++
65 lines
2.4 KiB
C++
#include "loratap.h"
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#include <algorithm>
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#include <cmath>
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#include <cstdio>
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#include <ctime>
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namespace roro::lora {
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static void le16(std::vector<uint8_t>& o, uint16_t v) { o.insert(o.end(), {uint8_t(v), uint8_t(v >> 8)}); }
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static void le32(std::vector<uint8_t>& o, uint32_t v) {
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o.insert(o.end(), {uint8_t(v), uint8_t(v >> 8), uint8_t(v >> 16), uint8_t(v >> 24)});
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}
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// LoRaTap's dBm encoding: -139 dBm plus the byte, clamped to what a byte holds.
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static uint8_t dbmByte(float dbm) {
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long v = std::lround(dbm + 139);
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return static_cast<uint8_t>(std::clamp(v, 0L, 255L));
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}
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std::string capturePath(int64_t utcSeconds) {
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time_t t = static_cast<time_t>(utcSeconds);
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struct tm u;
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gmtime_r(&t, &u);
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char buf[48];
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std::snprintf(buf, sizeof buf, "/captures/lora/%04d%02d%02d-%02d%02d%02d.pcap", u.tm_year + 1900, u.tm_mon + 1,
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u.tm_mday, u.tm_hour, u.tm_min, u.tm_sec);
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return buf;
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}
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void appendPcapHeader(std::vector<uint8_t>& out) {
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le32(out, 0xA1B2C3D4);
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le16(out, 2);
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le16(out, 4);
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le32(out, 0); // time zone
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le32(out, 0); // timestamp accuracy
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le32(out, 65535); // snap length
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le32(out, 270); // LINKTYPE_LORATAP
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}
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void appendRecord(std::vector<uint8_t>& out, uint32_t seconds, uint32_t micros, const RxInfo& rx, const uint8_t* data,
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size_t len) {
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uint32_t captured = static_cast<uint32_t>(kLoraTapSize + len);
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le32(out, seconds);
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le32(out, micros);
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le32(out, captured);
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le32(out, captured);
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uint32_t f = rx.frequencyHz;
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// The spec puts packet RSSI in quarter dB below 0 dB SNR (an SX127x formula), but Wireshark
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// reads it as -139 dBm plus the byte either way, and the SX1262 already gives dBm.
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uint8_t packetRssi = dbmByte(rx.rssi);
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long snr = std::clamp(std::lround(rx.snr * 4), -128L, 127L);
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out.insert(out.end(), {
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0, 0, 0, uint8_t(kLoraTapSize), // version 0, padding, length
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uint8_t(f >> 24), uint8_t(f >> 16), uint8_t(f >> 8), uint8_t(f),
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uint8_t(std::lround(rx.bandwidthKHz / 125)), rx.spreadingFactor,
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packetRssi, dbmByte(rx.rssi), dbmByte(rx.noiseFloor),
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static_cast<uint8_t>(static_cast<int8_t>(snr)), rx.syncWord,
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});
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if (len) out.insert(out.end(), data, data + len);
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}
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} // namespace roro::lora
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