feat(config): restrict flows to Paris and Dublin strategies (#1007)

src/config.rs

@@ -334,6 +334,16 @@ impl TrippyConfig {
  Self::build_config(args, cfg_file, platform)
  }
 
+ /// The maximum number of flows allowed.
+ ///
+ /// This is restricted to 1 for the classic strategy.
+ pub fn max_flows(&self) -> usize {
+ match self.multipath_strategy {
+ MultipathStrategy::Classic => 1,
+ _ => self.tui_max_flows,
+ }
+ }
+
  #[allow(clippy::too_many_lines)]
  fn build_config(args: Args, cfg_file: ConfigFile, platform: &Platform) -> anyhow::Result<Self> {
  let &Platform {
@@ -641,6 +651,7 @@ impl TrippyConfig {
  validate_strategy(multipath_strategy, unprivileged)?;
  validate_protocol_strategy(protocol, multipath_strategy)?;
  validate_multi(mode, protocol, &args.targets, dns_resolve_all)?;
+ validate_flows(mode, multipath_strategy)?;
  validate_ttl(first_ttl, max_ttl)?;
  validate_max_inflight(max_inflight)?;
  validate_read_timeout(read_timeout)?;
@@ -918,6 +929,17 @@ fn validate_multi(
  }
 }
 
+/// Validate that flows and dot mode are only used with udp protocol and paris
+/// or dublin multipath strategy.
+fn validate_flows(mode: Mode, strategy: MultipathStrategy) -> anyhow::Result<()> {
+ match (mode, strategy) {
+ (Mode::Flows | Mode::Dot, MultipathStrategy::Classic) => Err(anyhow!(
+ "this mode requires udp protocol with paris or dublin multipath strategy"
+ )),
+ _ => Ok(()),
+ }
+}
+
 /// Validate `first_ttl` and `max_ttl`.
 fn validate_ttl(first_ttl: u8, max_ttl: u8) -> anyhow::Result<()> {
  if (first_ttl as usize) < 1 || (first_ttl as usize) > MAX_HOPS {
@@ -1150,11 +1172,13 @@ mod tests {
  #[test_case("trip example.com --mode markdown", Ok(cfg().mode(Mode::Markdown).max_rounds(Some(10)).build()); "markdown mode")]
  #[test_case("trip example.com --mode csv", Ok(cfg().mode(Mode::Csv).max_rounds(Some(10)).build()); "csv mode")]
  #[test_case("trip example.com --mode json", Ok(cfg().mode(Mode::Json).max_rounds(Some(10)).build()); "json mode")]
- #[test_case("trip example.com --mode dot", Ok(cfg().mode(Mode::Dot).max_rounds(Some(10)).build()); "dot mode")]
- #[test_case("trip example.com --mode flows", Ok(cfg().mode(Mode::Flows).max_rounds(Some(10)).build()); "flows mode")]
+ #[test_case("trip example.com --mode dot --udp -R paris", Ok(cfg().mode(Mode::Dot).max_rounds(Some(10)).multipath_strategy(MultipathStrategy::Paris).protocol(Protocol::Udp).port_direction(PortDirection::FixedSrc(Port(1024))).build()); "dot mode")]
+ #[test_case("trip example.com --mode flows --udp -R paris", Ok(cfg().mode(Mode::Flows).max_rounds(Some(10)).multipath_strategy(MultipathStrategy::Paris).protocol(Protocol::Udp).port_direction(PortDirection::FixedSrc(Port(1024))).build()); "flows mode")]
  #[test_case("trip example.com --mode silent", Ok(cfg().mode(Mode::Silent).max_rounds(Some(10)).build()); "silent mode")]
  #[test_case("trip example.com -m tui", Ok(cfg().mode(Mode::Tui).build()); "tui mode short")]
  #[test_case("trip example.com --mode foo", Err(anyhow!(format!("error: one of the values isn't valid for an argument"))); "invalid mode")]
+ #[test_case("trip example.com --mode dot", Err(anyhow!(format!("this mode requires udp protocol with paris or dublin multipath strategy"))); "invalid dot mode")]
+ #[test_case("trip example.com --mode flows", Err(anyhow!(format!("this mode requires udp protocol with paris or dublin multipath strategy"))); "invalid flows mode")]
  fn test_mode(cmd: &str, expected: anyhow::Result<TrippyConfig>) {
  compare(parse_config(cmd), expected);
  }

src/main.rs

@@ -218,7 +218,7 @@ fn start_tracer(
  tracer_config,
  channel_config,
  cfg.tui_max_samples,
- cfg.tui_max_flows,
+ cfg.max_flows(),
  );
  let trace_data = backend.trace();
  thread::Builder::new()
@@ -344,7 +344,7 @@ fn make_tui_config(args: &TrippyConfig) -> TuiConfig {
  args.tui_geoip_mode,
  args.tui_max_addrs,
  args.tui_max_samples,
- args.tui_max_flows,
+ args.max_flows(),
  args.tui_theme,
  &args.tui_bindings,
  &args.tui_custom_columns,