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[fix](trx-server): use raw bytes for APRS position parsing

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The APRS info field is raw AX.25 bytes, not valid UTF-8.
from_utf8_lossy inserts multi-byte replacement characters, causing
panics when the position parser sliced by byte index. Switch
parse_aprs_position, parse_aprs_compressed, parse_aprs_lat, and
parse_aprs_lon to operate on &[u8] instead of &str.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>
This commit is contained in:
Stan Grams
2026-02-08 22:48:48 +01:00
parent 10c4b735cf
commit b98475037c
1 changed files with 36 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/trx-server/src/decode/aprs.rs
+36 -42
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@@ -384,10 +384,11 @@ fn parse_aprs(ax25: &Ax25Frame) -> AprsPacket {
.map(|d| format_call(d)) .map(|d| format_call(d))
.collect::<Vec<_>>() .collect::<Vec<_>>()
.join(","); .join(",");
let info_str = String::from_utf8_lossy(&ax25.info).to_string(); let info = &ax25.info;
let info_str = String::from_utf8_lossy(info).to_string();
let packet_type = if !info_str.is_empty() { let packet_type = if !info.is_empty() {
match info_str.as_bytes()[0] { match info[0] {
b'!' | b'=' | b'/' | b'@' => "Position", b'!' | b'=' | b'/' | b'@' => "Position",
b':' => "Message", b':' => "Message",
b'>' => "Status", b'>' => "Status",
@@ -407,7 +408,7 @@ fn parse_aprs(ax25: &Ax25Frame) -> AprsPacket {
let mut symbol_code = None; let mut symbol_code = None;
if packet_type == "Position" { if packet_type == "Position" {
if let Some(pos) = parse_aprs_position(&info_str) { if let Some(pos) = parse_aprs_position(info) {
lat = Some(pos.0); lat = Some(pos.0);
lon = Some(pos.1); lon = Some(pos.1);
symbol_table = Some(pos.2.to_string()); symbol_table = Some(pos.2.to_string());
@@ -429,61 +430,56 @@ fn parse_aprs(ax25: &Ax25Frame) -> AprsPacket {
} }
} }
fn parse_aprs_position(info_str: &str) -> Option<(f64, f64, char, char)> { fn parse_aprs_position(info: &[u8]) -> Option<(f64, f64, char, char)> {
if info_str.is_empty() { if info.is_empty() {
return None; return None;
} }
let bytes = info_str.as_bytes(); let dt = info[0];
let dt = bytes[0];
let pos_str = match dt { let pos = match dt {
b'!' | b'=' => &info_str[1..], b'!' | b'=' => &info[1..],
b'/' | b'@' => { b'/' | b'@' => {
if info_str.len() < 9 { if info.len() < 9 {
return None; return None;
} }
&info_str[8..] &info[8..]
} }
_ => return None, _ => return None,
}; };
if pos_str.is_empty() { if pos.is_empty() {
return None; return None;
} }
let first = pos_str.as_bytes()[0]; if pos[0] < b'0' || pos[0] > b'9' {
if first < b'0' || first > b'9' { return parse_aprs_compressed(pos);
return parse_aprs_compressed(pos_str);
} }
// Uncompressed: DDMM.MMN/DDDMM.MMEsYYY // Uncompressed: DDMM.MMN/DDDMM.MMEsYYY
if pos_str.len() < 19 { if pos.len() < 19 {
return None; return None;
} }
let lat_str = &pos_str[..8]; let sym_table = pos[8] as char;
let sym_table = pos_str.as_bytes()[8] as char; let sym_code = pos[18] as char;
let lon_str = &pos_str[9..18];
let sym_code = pos_str.as_bytes()[18] as char;
let lat = parse_aprs_lat(lat_str)?; let lat = parse_aprs_lat(&pos[..8])?;
let lon = parse_aprs_lon(lon_str)?; let lon = parse_aprs_lon(&pos[9..18])?;
Some((lat, lon, sym_table, sym_code)) Some((lat, lon, sym_table, sym_code))
} }
fn parse_aprs_compressed(pos_str: &str) -> Option<(f64, f64, char, char)> { fn parse_aprs_compressed(pos: &[u8]) -> Option<(f64, f64, char, char)> {
if pos_str.len() < 10 { if pos.len() < 10 {
return None; return None;
} }
let bytes = pos_str.as_bytes(); let sym_table = pos[0] as char;
let sym_table = bytes[0] as char;
let mut lat_val: u32 = 0; let mut lat_val: u32 = 0;
let mut lon_val: u32 = 0; let mut lon_val: u32 = 0;
for i in 0..4 { for i in 0..4 {
let lc = bytes[1 + i] as i32 - 33; let lc = pos[1 + i] as i32 - 33;
let xc = bytes[5 + i] as i32 - 33; let xc = pos[5 + i] as i32 - 33;
if lc < 0 || lc > 90 || xc < 0 || xc > 90 { if lc < 0 || lc > 90 || xc < 0 || xc > 90 {
return None; return None;
} }
@@ -498,22 +494,21 @@ fn parse_aprs_compressed(pos_str: &str) -> Option<(f64, f64, char, char)> {
return None; return None;
} }
let sym_code = bytes[9] as char; let sym_code = pos[9] as char;
let lat = (lat * 1e6).round() / 1e6; let lat = (lat * 1e6).round() / 1e6;
let lon = (lon * 1e6).round() / 1e6; let lon = (lon * 1e6).round() / 1e6;
Some((lat, lon, sym_table, sym_code)) Some((lat, lon, sym_table, sym_code))
} }
fn parse_aprs_lat(s: &str) -> Option<f64> { fn parse_aprs_lat(b: &[u8]) -> Option<f64> {
if s.len() < 8 { if b.len() < 8 {
return None; return None;
} }
let deg: f64 = s[..2].parse().ok()?; let deg: f64 = std::str::from_utf8(&b[..2]).ok()?.parse().ok()?;
let min: f64 = s[2..7].parse().ok()?; let min: f64 = std::str::from_utf8(&b[2..7]).ok()?.parse().ok()?;
let ns = s.as_bytes()[7];
let mut lat = deg + min / 60.0; let mut lat = deg + min / 60.0;
match ns { match b[7] {
b'S' | b's' => lat = -lat, b'S' | b's' => lat = -lat,
b'N' | b'n' => {} b'N' | b'n' => {}
_ => return None, _ => return None,
@@ -521,15 +516,14 @@ fn parse_aprs_lat(s: &str) -> Option<f64> {
Some((lat * 1e6).round() / 1e6) Some((lat * 1e6).round() / 1e6)
} }
fn parse_aprs_lon(s: &str) -> Option<f64> { fn parse_aprs_lon(b: &[u8]) -> Option<f64> {
if s.len() < 9 { if b.len() < 9 {
return None; return None;
} }
let deg: f64 = s[..3].parse().ok()?; let deg: f64 = std::str::from_utf8(&b[..3]).ok()?.parse().ok()?;
let min: f64 = s[3..8].parse().ok()?; let min: f64 = std::str::from_utf8(&b[3..8]).ok()?.parse().ok()?;
let ew = s.as_bytes()[8];
let mut lon = deg + min / 60.0; let mut lon = deg + min / 60.0;
match ew { match b[8] {
b'W' | b'w' => lon = -lon, b'W' | b'w' => lon = -lon,
b'E' | b'e' => {} b'E' | b'e' => {}
_ => return None, _ => return None,