From f2020470f26b09c3d022b88e75fe6a97519c3a5e Mon Sep 17 00:00:00 2001
From: Csaba Kiraly <csaba.kiraly@gmail.com>
Date: Mon, 14 Apr 2025 17:56:52 +0200
Subject: [PATCH] p2p: wrap internal error in new error type

Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>
---
 p2p/metrics.go |  3 ++-
 p2p/server.go  | 12 ++++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/p2p/metrics.go b/p2p/metrics.go
index e1bfe37ec3..b70c40e07a 100644
--- a/p2p/metrics.go
+++ b/p2p/metrics.go
@@ -68,6 +68,7 @@ func markDialError(err error) {
 		return
 	}
 
+	var e *protoHandshakeError
 	switch {
 	case errors.Is(err, DiscTooManyPeers):
 		dialTooManyPeers.Mark(1)
@@ -81,7 +82,7 @@ func markDialError(err error) {
 		dialUnexpectedIdentity.Mark(1)
 	case errors.Is(err, errEncHandshakeError):
 		dialEncHandshakeError.Mark(1)
-	case errors.Is(err, errProtoHandshakeError):
+	case errors.As(err, &e):
 		dialProtoHandshakeError.Mark(1)
 	}
 }
diff --git a/p2p/server.go b/p2p/server.go
index 21a14bb5f4..222b711f03 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -66,11 +66,15 @@ const (
 )
 
 var (
-	errServerStopped       = errors.New("server stopped")
-	errEncHandshakeError   = errors.New("rlpx enc error")
-	errProtoHandshakeError = errors.New("rlpx proto error")
+	errServerStopped     = errors.New("server stopped")
+	errEncHandshakeError = errors.New("rlpx enc error")
 )
 
+type protoHandshakeError struct{ err error }
+
+func (e *protoHandshakeError) Error() string { return fmt.Sprintf("rlpx proto error: %s", e.err) }
+func (e *protoHandshakeError) Unwrap() error { return e.err }
+
 // Server manages all peer connections.
 type Server struct {
 	// Config fields may not be modified while the server is running.
@@ -908,7 +912,7 @@ func (srv *Server) setupConn(c *conn, dialDest *enode.Node) error {
 	if err != nil {
 		clog.Trace("Failed p2p handshake", "err", err)
 		//Wrapping both errors for later inspection
-		return fmt.Errorf("%w: %w", errProtoHandshakeError, err)
+		return &protoHandshakeError{err: err}
 	}
 	if id := c.node.ID(); !bytes.Equal(crypto.Keccak256(phs.ID), id[:]) {
 		clog.Trace("Wrong devp2p handshake identity", "phsid", hex.EncodeToString(phs.ID))