feat: simple federation policies

basically can now fediblock instances, yayy, but more interestingly just
refuse to mirror media from problematic instances or refuse deliveries
for places we want to read but who shouldn't read us

upub/core/src/config.rs

@@ -18,6 +18,9 @@ pub struct Config {
 	#[serde(default)]
 	pub files: FileStorageConfig,
 
+	#[serde(default)]
+	pub reject: RejectConfig,
+
 	// TODO should i move app keys here?
 }
 
@@ -122,6 +125,19 @@ pub struct FileStorageConfig {
 	pub path: String,
 }
 
+#[serde_inline_default::serde_inline_default]
+#[derive(Debug, Clone, serde::Deserialize, serde::Serialize, serde_default::DefaultFromSerde)]
+pub struct RejectConfig {
+	#[serde(default)]
+	pub everything: Vec<String>,
+
+	#[serde(default)]
+	pub media: Vec<String>,
+
+	#[serde(default)]
+	pub delivery: Vec<String>,
+}
+
 impl Config {
 	pub fn load(path: Option<&std::path::PathBuf>) -> Self {
 		let Some(cfg_path) = path else { return Config::default() };

upub/routes/src/activitypub/application.rs

@@ -120,6 +120,11 @@ pub async fn cloak_proxy(
 	let uri = ctx.uncloak(&hmac, &uri)
 		.ok_or_else(ApiError::unauthorized)?;
 
+	let stripped = uri.replace("https://", "").replace("http://", "");
+	if ctx.cfg().reject.media.iter().any(|x| stripped.starts_with(x)) {
+		return Err(ApiError::Status(axum::http::StatusCode::UNAVAILABLE_FOR_LEGAL_REASONS));
+	}
+
 	let resp = Context::client(ctx.domain())
 		.get(uri)
 		.send()

upub/routes/src/activitypub/inbox.rs

@@ -43,7 +43,7 @@ pub async fn post(
 	AuthIdentity(auth): AuthIdentity,
 	Json(activity): Json<serde_json::Value>
 ) -> crate::ApiResult<StatusCode> {
-	let Identity::Remote { domain: _server, user: uid, .. } = auth else {
+	let Identity::Remote { domain, user: uid, .. } = auth else {
 		if matches!(activity.activity_type(), Ok(ActivityType::Delete)) {
 			// this is spammy af, ignore them!
 			// we basically received a delete for a user we can't fetch and verify, meaning remote
@@ -64,6 +64,10 @@ pub async fn post(
 		}
 	};
 
+	if ctx.cfg().reject.everything.contains(&domain) {
+		return Err(crate::ApiError::Status(StatusCode::UNAVAILABLE_FOR_LEGAL_REASONS));
+	}
+
 	let aid = activity.id()?.to_string();
 	let server = upub::Context::server(&aid);
 

upub/worker/src/outbound.rs

@@ -185,6 +185,18 @@ pub async fn process(ctx: Context, job: &model::job::Model) -> crate::JobResult<
 			targets.push(relay);
 		}
 	}
+
+	targets
+		.retain(|target| {
+			let stripped = target.replace("https://", "").replace("http://", "");
+			if ctx.cfg().reject.delivery.iter().any(|x| stripped.starts_with(x)) {
+				tracing::warn!("rejecting delivery of {} to {target}", job.activity);
+				false
+			} else {
+				true
+			}
+		});
+
 	ctx.deliver(targets, &job.activity, &job.actor, &tx).await?;
 
 	tx.commit().await?;