exerrors: Add IsNetworkError helper

Author: hifi

exerrors/network.go

@@ -0,0 +1,39 @@
+// Copyright (c) 2025 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package exerrors
+
+import (
+	"errors"
+	"net"
+	"syscall"
+)
+
+func IsNetworkError(err error) bool {
+	for err != nil {
+		if _, ok := err.(net.Error); ok {
+			return true
+		} else if _, ok := err.(*net.OpError); ok {
+			return true
+		} else if errno, ok := err.(syscall.Errno); ok {
+			// common errnos for network related operations
+			return errno == syscall.ENETDOWN ||
+				errno == syscall.ENETUNREACH ||
+				errno == syscall.ENETRESET ||
+				errno == syscall.ECONNABORTED ||
+				errno == syscall.ECONNRESET ||
+				errno == syscall.ENOBUFS ||
+				errno == syscall.ETIMEDOUT ||
+				errno == syscall.ECONNREFUSED ||
+				errno == syscall.EHOSTDOWN ||
+				errno == syscall.EHOSTUNREACH
+		}
+
+		err = errors.Unwrap(err)
+	}
+
+	return false
+}