From 4e77e67f1085cbf3802f930dc1aeb4f0185130ea Mon Sep 17 00:00:00 2001
From: Karolin Varner <karo@cupdev.net>
Date: Sun, 1 Jun 2025 20:10:03 +0200
Subject: [PATCH] chore: Split utils for zerocopy in protocol into own file

---
 rosenpass/src/protocol/mod.rs      |  1 +
 rosenpass/src/protocol/protocol.rs | 15 +--------------
 rosenpass/src/protocol/test.rs     |  5 +++--
 rosenpass/src/protocol/zerocopy.rs | 21 +++++++++++++++++++++
 4 files changed, 26 insertions(+), 16 deletions(-)
 create mode 100644 rosenpass/src/protocol/zerocopy.rs

diff --git a/rosenpass/src/protocol/mod.rs b/rosenpass/src/protocol/mod.rs
index eb20947..93f9e86 100644
--- a/rosenpass/src/protocol/mod.rs
+++ b/rosenpass/src/protocol/mod.rs
@@ -81,6 +81,7 @@ pub mod basic_types;
 pub mod constants;
 pub mod testutils;
 pub mod timing;
+pub mod zerocopy;
 
 #[allow(clippy::module_inception)]
 mod protocol;
diff --git a/rosenpass/src/protocol/protocol.rs b/rosenpass/src/protocol/protocol.rs
index b36ee6d..2464b06 100644
--- a/rosenpass/src/protocol/protocol.rs
+++ b/rosenpass/src/protocol/protocol.rs
@@ -45,6 +45,7 @@ use super::constants::{
     RETRANSMIT_DELAY_GROWTH, RETRANSMIT_DELAY_JITTER,
 };
 use super::timing::{has_happened, Timing, BCE, UNENDING};
+use super::zerocopy::{truncating_cast_into, truncating_cast_into_nomut};
 
 #[cfg(feature = "trace_bench")]
 use rosenpass_util::trace_bench::Trace as _;
@@ -3949,17 +3950,3 @@ impl CryptoServer {
         }
     }
 }
-
-/// Used to parse a network message using [zerocopy]
-pub fn truncating_cast_into<T: FromBytes>(
-    buf: &mut [u8],
-) -> Result<Ref<&mut [u8], T>, RosenpassError> {
-    Ref::new(&mut buf[..size_of::<T>()]).ok_or(RosenpassError::BufferSizeMismatch)
-}
-
-/// Used to parse a network message using [zerocopy], mutably
-pub fn truncating_cast_into_nomut<T: FromBytes>(
-    buf: &[u8],
-) -> Result<Ref<&[u8], T>, RosenpassError> {
-    Ref::new(&buf[..size_of::<T>()]).ok_or(RosenpassError::BufferSizeMismatch)
-}
diff --git a/rosenpass/src/protocol/test.rs b/rosenpass/src/protocol/test.rs
index 1873a57..f62775b 100644
--- a/rosenpass/src/protocol/test.rs
+++ b/rosenpass/src/protocol/test.rs
@@ -14,8 +14,9 @@ use crate::msgs::{EmptyData, Envelope, InitConf, InitHello, MsgType, RespHello,
 use super::{
     basic_types::{MsgBuf, SPk, SSk, SymKey},
     constants::REKEY_AFTER_TIME_RESPONDER,
-    truncating_cast_into, truncating_cast_into_nomut, CryptoServer, HandleMsgResult,
-    HostIdentification, KnownInitConfResponsePtr, PeerPtr, PollResult, ProtocolVersion,
+    zerocopy::{truncating_cast_into, truncating_cast_into_nomut},
+    CryptoServer, HandleMsgResult, HostIdentification, KnownInitConfResponsePtr, PeerPtr,
+    PollResult, ProtocolVersion,
 };
 
 struct VecHostIdentifier(Vec<u8>);
diff --git a/rosenpass/src/protocol/zerocopy.rs b/rosenpass/src/protocol/zerocopy.rs
new file mode 100644
index 0000000..3e8639b
--- /dev/null
+++ b/rosenpass/src/protocol/zerocopy.rs
@@ -0,0 +1,21 @@
+//! Helpers for working with the zerocopy crate
+
+use std::mem::size_of;
+
+use zerocopy::{FromBytes, Ref};
+
+use crate::RosenpassError;
+
+/// Used to parse a network message using [zerocopy]
+pub fn truncating_cast_into<T: FromBytes>(
+    buf: &mut [u8],
+) -> Result<Ref<&mut [u8], T>, RosenpassError> {
+    Ref::new(&mut buf[..size_of::<T>()]).ok_or(RosenpassError::BufferSizeMismatch)
+}
+
+/// Used to parse a network message using [zerocopy], mutably
+pub fn truncating_cast_into_nomut<T: FromBytes>(
+    buf: &[u8],
+) -> Result<Ref<&[u8], T>, RosenpassError> {
+    Ref::new(&buf[..size_of::<T>()]).ok_or(RosenpassError::BufferSizeMismatch)
+}