1 /* SPDX-License-Identifier: LGPL-2.1-or-later */ 2 #pragma once 3 4 /* Length of a single label, with all escaping removed, excluding any trailing dot or NUL byte */ 5 #define DNS_LABEL_MAX 63 6 7 /* Worst case length of a single label, with all escaping applied and room for a trailing NUL byte. */ 8 #define DNS_LABEL_ESCAPED_MAX (DNS_LABEL_MAX*4+1) 9 10 /* Maximum length of a full hostname, consisting of a series of unescaped labels, and no trailing dot or NUL byte */ 11 #define DNS_HOSTNAME_MAX 253 12 13 /* Maximum length of a full hostname, on the wire, including the final NUL byte */ 14 #define DNS_WIRE_FORMAT_HOSTNAME_MAX 255 15 16 /* Maximum number of labels per valid hostname */ 17 #define DNS_N_LABELS_MAX 127 18