From 3307715a8d8bdeac1b2d7df66ec2abb6e503ba9a Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Fri, 6 Mar 2026 13:01:12 +0800
Subject: format/pktline: Add pktline

---
 format/pktline/errors.go | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 format/pktline/errors.go

(limited to 'format/pktline/errors.go')

diff --git a/format/pktline/errors.go b/format/pktline/errors.go
new file mode 100644
index 00000000..d07227e6
--- /dev/null
+++ b/format/pktline/errors.go
@@ -0,0 +1,34 @@
+package pktline
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	// ErrInvalidLength indicates a malformed 4-byte hexadecimal length header.
+	ErrInvalidLength = errors.New("pktline: invalid length header")
+	// ErrTooLarge indicates a payload exceeds configured packet data limits.
+	ErrTooLarge = errors.New("pktline: payload too large")
+)
+
+// ProtocolError reports invalid pkt-line framing.
+//
+// It is returned for protocol violations such as invalid control values
+// (for example 0003) or non-hex length headers.
+type ProtocolError struct {
+	Header [4]byte
+	Reason string
+}
+
+func (e *ProtocolError) Error() string {
+	if e == nil {
+		return "<nil>"
+	}
+
+	if e.Reason == "" {
+		return "pktline: protocol error"
+	}
+
+	return fmt.Sprintf("pktline: protocol error: %s", e.Reason)
+}
-- 
cgit v1.3.1-10-gc9f91