Move Protocol to monero-wallet

coins/monero/wallet/src/lib.rs

@@ -4,7 +4,10 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use core::ops::Deref;
-use std_shims::collections::{HashSet, HashMap};
+use std_shims::{
+  io,
+  collections::{HashSet, HashMap},
+};
 
 use zeroize::{Zeroize, ZeroizeOnDrop, Zeroizing};
 
@@ -15,9 +18,9 @@ use curve25519_dalek::{
 };
 
 use monero_serai::{
-  io::write_varint,
+  io::{read_byte, read_u16, write_varint},
   primitives::{Commitment, keccak256, keccak256_to_scalar},
-  ringct::EncryptedAmount,
+  ringct::{RctType, EncryptedAmount},
   transaction::Input,
 };
 pub use monero_serai as monero;
@@ -58,6 +61,137 @@ pub use send::TransactionMachine;
 #[cfg(test)]
 mod tests;
 
+/// Monero protocol version.
+///
+/// v15 is omitted as v15 was simply v14 and v16 being active at the same time, with regards to the
+/// transactions supported. Accordingly, v16 should be used during v15.
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
+#[allow(non_camel_case_types)]
+pub enum Protocol {
+  v14,
+  v16,
+  Custom {
+    ring_len: usize,
+    bp_plus: bool,
+    optimal_rct_type: RctType,
+    view_tags: bool,
+    v16_fee: bool,
+  },
+}
+
+impl TryFrom<u8> for Protocol {
+  type Error = ();
+  fn try_from(version: u8) -> Result<Self, ()> {
+    Ok(match version {
+      14 => Protocol::v14, // TODO: 13 | 14?
+      15 | 16 => Protocol::v16,
+      _ => Err(())?,
+    })
+  }
+}
+
+impl Protocol {
+  /// Amount of ring members under this protocol version.
+  pub fn ring_len(&self) -> usize {
+    match self {
+      Protocol::v14 => 11,
+      Protocol::v16 => 16,
+      Protocol::Custom { ring_len, .. } => *ring_len,
+    }
+  }
+
+  /// Whether or not the specified version uses Bulletproofs or Bulletproofs+.
+  ///
+  /// This method will likely be reworked when versions not using Bulletproofs at all are added.
+  pub fn bp_plus(&self) -> bool {
+    match self {
+      Protocol::v14 => false,
+      Protocol::v16 => true,
+      Protocol::Custom { bp_plus, .. } => *bp_plus,
+    }
+  }
+
+  // TODO: Make this an Option when we support pre-RCT protocols
+  pub fn optimal_rct_type(&self) -> RctType {
+    match self {
+      Protocol::v14 => RctType::Clsag,
+      Protocol::v16 => RctType::BulletproofsPlus,
+      Protocol::Custom { optimal_rct_type, .. } => *optimal_rct_type,
+    }
+  }
+
+  /// Whether or not the specified version uses view tags.
+  pub fn view_tags(&self) -> bool {
+    match self {
+      Protocol::v14 => false,
+      Protocol::v16 => true,
+      Protocol::Custom { view_tags, .. } => *view_tags,
+    }
+  }
+
+  /// Whether or not the specified version uses the fee algorithm from Monero
+  /// hard fork version 16 (released in v18 binaries).
+  pub fn v16_fee(&self) -> bool {
+    match self {
+      Protocol::v14 => false,
+      Protocol::v16 => true,
+      Protocol::Custom { v16_fee, .. } => *v16_fee,
+    }
+  }
+
+  pub fn write<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
+    match self {
+      Protocol::v14 => w.write_all(&[0, 14]),
+      Protocol::v16 => w.write_all(&[0, 16]),
+      Protocol::Custom { ring_len, bp_plus, optimal_rct_type, view_tags, v16_fee } => {
+        // Custom, version 0
+        w.write_all(&[1, 0])?;
+        w.write_all(&u16::try_from(*ring_len).unwrap().to_le_bytes())?;
+        w.write_all(&[u8::from(*bp_plus)])?;
+        w.write_all(&[optimal_rct_type.to_byte()])?;
+        w.write_all(&[u8::from(*view_tags)])?;
+        w.write_all(&[u8::from(*v16_fee)])
+      }
+    }
+  }
+
+  pub fn read<R: io::Read>(r: &mut R) -> io::Result<Protocol> {
+    Ok(match read_byte(r)? {
+      // Monero protocol
+      0 => match read_byte(r)? {
+        14 => Protocol::v14,
+        16 => Protocol::v16,
+        _ => Err(io::Error::other("unrecognized monero protocol"))?,
+      },
+      // Custom
+      1 => match read_byte(r)? {
+        0 => Protocol::Custom {
+          ring_len: read_u16(r)?.into(),
+          bp_plus: match read_byte(r)? {
+            0 => false,
+            1 => true,
+            _ => Err(io::Error::other("invalid bool serialization"))?,
+          },
+          optimal_rct_type: RctType::from_byte(read_byte(r)?)
+            .ok_or_else(|| io::Error::other("invalid RctType serialization"))?,
+          view_tags: match read_byte(r)? {
+            0 => false,
+            1 => true,
+            _ => Err(io::Error::other("invalid bool serialization"))?,
+          },
+          v16_fee: match read_byte(r)? {
+            0 => false,
+            1 => true,
+            _ => Err(io::Error::other("invalid bool serialization"))?,
+          },
+        },
+        _ => Err(io::Error::other("unrecognized custom protocol serialization"))?,
+      },
+      _ => Err(io::Error::other("unrecognized protocol serialization"))?,
+    })
+  }
+}
+
 fn key_image_sort(x: &EdwardsPoint, y: &EdwardsPoint) -> core::cmp::Ordering {
   x.compress().to_bytes().cmp(&y.compress().to_bytes()).reverse()
 }