From 9e815cf2c2d8463e58c6609edb6a33f9bb62e7b5 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 11 Dec 2020 16:26:04 +0100
Subject: [PATCH] hostname-util: explain what 'LDH' is

---
 src/basic/hostname-util.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/basic/hostname-util.c b/src/basic/hostname-util.c
index 5c3157fdf2..82cd37b154 100644
--- a/src/basic/hostname-util.c
+++ b/src/basic/hostname-util.c
@@ -89,6 +89,8 @@ int gethostname_strict(char **ret) {
 }
 
 bool valid_ldh_char(char c) {
+        /* "LDH" → "Letters, digits, hyphens", as per RFC 5890, Section 2.3.1 */
+
         return
                 (c >= 'a' && c <= 'z') ||
                 (c >= 'A' && c <= 'Z') ||