serve well-known client and server config

This way users can have a simpler time configuring this stuff and we can
worry about the spec compliance parts and specifying the same thing over
and over parts.

src/config.rs

@@ -30,7 +30,13 @@ pub(crate) struct Config {
     pub(crate) listen: Vec<ListenConfig>,
     pub(crate) tls: Option<TlsConfig>,
 
+    /// The name of this homeserver
+    ///
+    /// This is the value that will appear e.g. in user IDs and room aliases.
     pub(crate) server_name: OwnedServerName,
+
+    #[serde(default)]
+    pub(crate) server_discovery: ServerDiscovery,
     pub(crate) database: DatabaseConfig,
     #[serde(default)]
     pub(crate) federation: FederationConfig,
@@ -63,6 +69,35 @@ pub(crate) struct Config {
     pub(crate) emergency_password: Option<String>,
 }
 
+#[derive(Debug, Default, Deserialize)]
+pub(crate) struct ServerDiscovery {
+    /// Server-server discovery configuration
+    #[serde(default)]
+    pub(crate) server: ServerServerDiscovery,
+
+    /// Client-server discovery configuration
+    #[serde(default)]
+    pub(crate) client: ClientServerDiscovery,
+}
+
+/// Server-server discovery configuration
+#[derive(Debug, Default, Deserialize)]
+pub(crate) struct ServerServerDiscovery {
+    /// The alternative authority to make server-server API requests to
+    pub(crate) authority: Option<OwnedServerName>,
+}
+
+/// Client-server discovery configuration
+#[derive(Debug, Default, Deserialize)]
+pub(crate) struct ClientServerDiscovery {
+    /// The alternative authority to make client-server API requests to
+    pub(crate) authority: Option<OwnedServerName>,
+
+    /// Controls whether HTTPS is used
+    #[serde(default)]
+    pub(crate) insecure: bool,
+}
+
 #[derive(Debug, Deserialize)]
 pub(crate) struct TlsConfig {
     pub(crate) certs: String,