Get all processors to compile again

Requires splitting `serai-cosign` into `serai-cosign` and `serai-cosign-types`
so the processor don't require `serai-client/serai` (not correct yet).

coordinator/cosign/Cargo.toml

@@ -31,3 +31,5 @@ tokio = { version = "1", default-features = false }
 
 serai-db = { path = "../../common/db", version = "0.1.1" }
 serai-task = { path = "../../common/task", version = "0.1" }
+
+serai-cosign-types = { path = "./types" }

coordinator/cosign/src/lib.rs

@@ -19,6 +19,8 @@ use serai_client::{
 use serai_db::*;
 use serai_task::*;
 
+use serai_cosign_types::*;
+
 /// The cosigns which are intended to be performed.
 mod intend;
 /// The evaluator of the cosigns.

coordinator/cosign/types/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "serai-cosign-types"
+version = "0.1.0"
+description = "Evaluator of cosigns for the Serai network"
+license = "AGPL-3.0-only"
+repository = "https://github.com/serai-dex/serai/tree/develop/coordinator/cosign"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+keywords = []
+edition = "2021"
+publish = false
+rust-version = "1.85"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[lints]
+workspace = true
+
+[dependencies]
+schnorrkel = { version = "0.11", default-features = false, features = ["std"] }
+
+borsh = { version = "1", default-features = false, features = ["std", "derive", "de_strict_order"] }
+
+serai-primitives = { path = "../../../substrate/primitives", default-features = false, features = ["std"] }

coordinator/cosign/types/LICENSE

@@ -0,0 +1,15 @@
+AGPL-3.0-only license
+
+Copyright (c) 2023-2025 Luke Parker
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License Version 3 as
+published by the Free Software Foundation.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.

coordinator/cosign/types/src/lib.rs

@@ -0,0 +1,72 @@
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![deny(missing_docs)]
+//! Types used when cosigning Serai. For more info, please see `serai-cosign`.
+use borsh::{BorshSerialize, BorshDeserialize};
+
+use serai_primitives::{crypto::Public, network_id::ExternalNetworkId};
+
+/// The schnorrkel context to used when signing a cosign.
+pub const COSIGN_CONTEXT: &[u8] = b"/serai/coordinator/cosign";
+
+/// An intended cosign.
+#[derive(Clone, Copy, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
+pub struct CosignIntent {
+  /// The global session this cosign is being performed under.
+  pub global_session: [u8; 32],
+  /// The number of the block to cosign.
+  pub block_number: u64,
+  /// The hash of the block to cosign.
+  pub block_hash: [u8; 32],
+  /// If this cosign must be handled before further cosigns are.
+  pub notable: bool,
+}
+
+/// A cosign.
+#[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
+pub struct Cosign {
+  /// The global session this cosign is being performed under.
+  pub global_session: [u8; 32],
+  /// The number of the block to cosign.
+  pub block_number: u64,
+  /// The hash of the block to cosign.
+  pub block_hash: [u8; 32],
+  /// The actual cosigner.
+  pub cosigner: ExternalNetworkId,
+}
+
+impl CosignIntent {
+  /// Convert this into a `Cosign`.
+  pub fn into_cosign(self, cosigner: ExternalNetworkId) -> Cosign {
+    let CosignIntent { global_session, block_number, block_hash, notable: _ } = self;
+    Cosign { global_session, block_number, block_hash, cosigner }
+  }
+}
+
+impl Cosign {
+  /// The message to sign to sign this cosign.
+  ///
+  /// This must be signed with schnorrkel, the context set to `COSIGN_CONTEXT`.
+  pub fn signature_message(&self) -> Vec<u8> {
+    // We use a schnorrkel context to domain-separate this
+    borsh::to_vec(self).unwrap()
+  }
+}
+
+/// A signed cosign.
+#[derive(Clone, Debug, BorshSerialize, BorshDeserialize)]
+pub struct SignedCosign {
+  /// The cosign.
+  pub cosign: Cosign,
+  /// The signature for the cosign.
+  pub signature: [u8; 64],
+}
+
+impl SignedCosign {
+  /// Verify a cosign's signature.
+  pub fn verify_signature(&self, signer: Public) -> bool {
+    let Ok(signer) = schnorrkel::PublicKey::from_bytes(&signer.0) else { return false };
+    let Ok(signature) = schnorrkel::Signature::from_bytes(&self.signature) else { return false };
+
+    signer.verify_simple(COSIGN_CONTEXT, &self.cosign.signature_message(), &signature).is_ok()
+  }
+}