1 files changed, 44 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,
         })