feat: more federation policies

also allow to prevent access via http signatures or straight out reject
all fetches. note that this last option is rather ineffective as remotes
can just fetch public objects anonimously

upub/core/src/config.rs

@@ -136,6 +136,12 @@ pub struct RejectConfig {
 
 	#[serde(default)]
 	pub delivery: Vec<String>,
+
+	#[serde(default)]
+	pub fetch: Vec<String>,
+
+	#[serde(default)]
+	pub access: Vec<String>,
 }
 
 impl Config {

upub/routes/src/auth.rs

@@ -150,10 +150,16 @@ where
 						return Err(ApiError::unauthorized());
 					}
 
-					let internal = upub::model::instance::Entity::domain_to_internal(&user.domain, ctx.db())
+					if ctx.cfg().reject.fetch.contains(&user.domain) {
-						.await?
+						return Err(ApiError::Status(axum::http::StatusCode::UNAVAILABLE_FOR_LEGAL_REASONS));
-						.ok_or_else(ApiError::internal_server_error)?; // user but not their domain???
+					}
-					identity = Identity::Remote { user: user.id, domain: user.domain, internal };
+
+					if !ctx.cfg().reject.access.contains(&user.domain) {
+						let internal = upub::model::instance::Entity::domain_to_internal(&user.domain, ctx.db())
+							.await?
+							.ok_or_else(ApiError::internal_server_error)?; // user but not their domain???
+						identity = Identity::Remote { user: user.id, domain: user.domain, internal };
+					}
 				},
 			}