move transport config checks to respective modules

4 files changed, 96 insertions, 15 deletions

diff --git a/src/transport/libp2p.rs b/src/transport/libp2p.rs
index 2d67d2c..d023079 100644
--- a/src/transport/libp2p.rs
+++ b/src/transport/libp2p.rs
@@ -204,6 +204,48 @@ pub(crate) struct Libp2pConfig {
     pub(crate) memory: bool,
 }
 
+/// The multiaddrs of option `option`.
+fn parse_addresses(option: &str, addresses: &[String]) -> Result<Vec<Multiaddr>> {
+    addresses
+        .iter()
+        .map(|address| {
+            address
+                .parse::<Multiaddr>()
+                .with_context(|| format!("{option} {address:?}"))
+        })
+        .collect()
+}
+
+/// The ranges of `libp2p-ignore`.
+fn parse_ranges(ranges: &[String]) -> Result<Vec<IpRange>> {
+    ranges
+        .iter()
+        .map(|range| range.parse().context("libp2p-ignore"))
+        .collect()
+}
+
+/// This transport's options, checked when the configuration is loaded
+/// (`config::Settings::check`), so `--print-config` tells a wrong one too: the
+/// multiaddrs and ranges parse, and a relay that is no node (`--relay-only`) can be
+/// dialled and keeps its peer ID.
+pub(crate) fn check(settings: &crate::config::Settings) -> Result<()> {
+    parse_addresses("libp2p-listen", &settings.libp2p_listen)?;
+    parse_addresses("libp2p-announce", &settings.libp2p_announce)?;
+    parse_addresses("libp2p-relays", &settings.libp2p_relays)?;
+    parse_ranges(&settings.libp2p_ignore)?;
+    if settings.relay_only {
+        if settings.libp2p_listen.is_empty() {
+            bail!("relay-only needs libp2p-listen: where nodes reach the relay");
+        }
+        if settings.libp2p_key_file.is_none() {
+            bail!(
+                "relay-only needs libp2p-key-file: without it, the relay's peer ID changes with every start and nodes lose it"
+            );
+        }
+    }
+    Ok(())
+}
+
 impl Libp2pConfig {
     /// The configuration `settings` give; `relay_only`: a relay that is no node
     /// (`--relay-only`).
@@ -211,16 +253,7 @@ impl Libp2pConfig {
         settings: &crate::config::Settings,
         relay_only: bool,
     ) -> Result<Self> {
-        let parse = |option: &str, addresses: &[String]| {
-            addresses
-                .iter()
-                .map(|address| {
-                    address
-                        .parse::<Multiaddr>()
-                        .with_context(|| format!("{option} {address:?}"))
-                })
-                .collect::<Result<Vec<_>>>()
-        };
+        let parse = parse_addresses;
         Ok(Self {
             key: Self::load_key(settings.libp2p_key_file.as_deref())?,
             listen: parse("libp2p-listen", &settings.libp2p_listen)?,
@@ -230,11 +263,7 @@ impl Libp2pConfig {
             continuum: !relay_only,
             mdns: settings.libp2p_mdns,
             upnp: settings.libp2p_upnp,
-            ignore: settings
-                .libp2p_ignore
-                .iter()
-                .map(|range| range.parse().context("libp2p-ignore"))
-                .collect::<Result<Vec<_>>>()?,
+            ignore: parse_ranges(&settings.libp2p_ignore)?,
             public: settings.libp2p_public,
             memory: false,
         })
diff --git a/src/transport/mod.rs b/src/transport/mod.rs
index d8c6e2b..fd3651b 100644
--- a/src/transport/mod.rs
+++ b/src/transport/mod.rs
@@ -34,6 +34,27 @@ compile_error!(
     "continuum needs a transport: build with at least one of the mycelium, libp2p and tor features, e.g. `cargo build --features mycelium`"
 );
 
+/// The options of the transports this build has, each checked by its transport when the
+/// configuration is loaded (`config::Settings::check`, after the names in `transports`):
+/// Mycelium's always (its conflicts are errors wherever they come from, as before);
+/// libp2p's and Tor's if the node uses them. Options of transports not built aren't
+/// checked: they're ignored, and said so (`config::Loaded::unused_transport_options`).
+pub(crate) fn check(settings: &crate::config::Settings) -> Result<()> {
+    let uses = |name: &str| settings.transports.iter().any(|used| used == name);
+    let _ = uses;
+    #[cfg(feature = "mycelium")]
+    mycelium::check(settings)?;
+    #[cfg(feature = "libp2p")]
+    if uses("libp2p") {
+        libp2p::check(settings)?;
+    }
+    #[cfg(feature = "tor")]
+    if uses("tor") {
+        tor::TorTransport::check(settings)?;
+    }
+    Ok(())
+}
+
 /// Starts the transport `name` (one of `config::TRANSPORTS`) as `settings` configure
 /// it: its scheme and the transport, or None if `stop` came first (some take a while to
 /// start: a supervised Mycelium daemon, arti). `key`: the node key, which some prove
diff --git a/src/transport/mycelium/mod.rs b/src/transport/mycelium/mod.rs
index 7abcced..20abee8 100644
--- a/src/transport/mycelium/mod.rs
+++ b/src/transport/mycelium/mod.rs
@@ -91,6 +91,26 @@ pub(crate) struct MyceliumTransport {
     local_id: String,
 }
 
+/// This transport's options, checked when the configuration is loaded
+/// (`config::Settings::check`): a daemon elsewhere (`mycelium-rest-url`) by a URL, and
+/// none of the options only a supervised one takes with it; a private network with
+/// both its key and its name.
+pub(crate) fn check(settings: &crate::config::Settings) -> Result<()> {
+    if let Some(url) = &settings.mycelium_rest_url {
+        Url::parse(url).with_context(|| format!("mycelium-rest-url {url:?}"))?;
+        if let Some((name, _)) = settings.supervised_only().iter().find(|(_, set)| *set) {
+            anyhow::bail!(
+                "{name} is for a supervised Mycelium daemon and can't be combined with mycelium-rest-url"
+            );
+        }
+    }
+    // A private network has both; one alone would be ignored or invented.
+    if settings.mycelium_network_key_file.is_some() != settings.mycelium_network_name.is_some() {
+        anyhow::bail!("mycelium-network-key-file and mycelium-network-name go together");
+    }
+    Ok(())
+}
+
 /// The transport as `settings` configure it (`transport::start`): its daemon supervised
 /// (started, which can take a while) or one running elsewhere. None if `stop` came
 /// first.
diff --git a/src/transport/tor.rs b/src/transport/tor.rs
index 8eb1d02..f2e0199 100644
--- a/src/transport/tor.rs
+++ b/src/transport/tor.rs
@@ -198,6 +198,17 @@ impl TorTransport {
     /// while: it fetches what it needs to know of the Tor network). Until it is done,
     /// dials wait for it (arti bootstraps on demand), and the onion service is published
     /// once it is: the node starts without waiting for Tor.
+    /// This transport's options, checked when the configuration is loaded
+    /// (`config::Settings::check`), if the node uses it: where arti keeps its state.
+    pub(crate) fn check(settings: &crate::config::Settings) -> Result<()> {
+        if settings.tor_state_dir.is_none() {
+            bail!(
+                "tor needs tor-state-dir: where arti keeps its state, the onion service's key among it"
+            );
+        }
+        Ok(())
+    }
+
     /// The transport as `settings` configure it (`transport::start`), proving `key`.
     /// None if `stop` came first (bootstrapping arti can take a while).
     pub(crate) async fn from_settings(