Refactor server_keys service/interface and related callsites

Signed-off-by: Jason Volk <jason@zemos.net>
Signed-off-by: strawberry <strawberry@puppygock.gay>

src/service/server_keys/keypair.rs

@@ -0,0 +1,64 @@
+use std::sync::Arc;
+
+use conduit::{debug, debug_info, err, error, utils, utils::string_from_bytes, Result};
+use database::Database;
+use ruma::{api::federation::discovery::VerifyKey, serde::Base64, signatures::Ed25519KeyPair};
+
+use super::VerifyKeys;
+
+pub(super) fn init(db: &Arc<Database>) -> Result<(Box<Ed25519KeyPair>, VerifyKeys)> {
+	let keypair = load(db).inspect_err(|_e| {
+		error!("Keypair invalid. Deleting...");
+		remove(db);
+	})?;
+
+	let verify_key = VerifyKey {
+		key: Base64::new(keypair.public_key().to_vec()),
+	};
+
+	let id = format!("ed25519:{}", keypair.version());
+	let verify_keys: VerifyKeys = [(id.try_into()?, verify_key)].into();
+
+	Ok((keypair, verify_keys))
+}
+
+fn load(db: &Arc<Database>) -> Result<Box<Ed25519KeyPair>> {
+	let (version, key) = db["global"]
+		.get_blocking(b"keypair")
+		.map(|ref val| {
+			// database deserializer is having trouble with this so it's manual for now
+			let mut elems = val.split(|&b| b == b'\xFF');
+			let vlen = elems.next().expect("invalid keypair entry").len();
+			let ver = string_from_bytes(&val[..vlen]).expect("invalid keypair version");
+			let der = val[vlen.saturating_add(1)..].to_vec();
+			debug!("Found existing Ed25519 keypair: {ver:?}");
+			(ver, der)
+		})
+		.or_else(|e| {
+			assert!(e.is_not_found(), "unexpected error fetching keypair");
+			create(db)
+		})?;
+
+	let key =
+		Ed25519KeyPair::from_der(&key, version).map_err(|e| err!("Failed to load ed25519 keypair from der: {e:?}"))?;
+
+	Ok(Box::new(key))
+}
+
+fn create(db: &Arc<Database>) -> Result<(String, Vec<u8>)> {
+	let keypair = Ed25519KeyPair::generate().map_err(|e| err!("Failed to generate new ed25519 keypair: {e:?}"))?;
+
+	let id = utils::rand::string(8);
+	debug_info!("Generated new Ed25519 keypair: {id:?}");
+
+	let value: (String, Vec<u8>) = (id, keypair.to_vec());
+	db["global"].raw_put(b"keypair", &value);
+
+	Ok(value)
+}
+
+#[inline]
+fn remove(db: &Arc<Database>) {
+	let global = &db["global"];
+	global.remove(b"keypair");
+}