1/* Compare two binary domain names for quality.
2 Copyright (C) 2022-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <arpa/nameser.h>
20#include <stdbool.h>
21
22/* Convert ASCII letters to upper case. */
23static inline int
24ascii_toupper (unsigned char ch)
25{
26 if (ch >= 'a' && ch <= 'z')
27 return ch - 'a' + 'A';
28 else
29 return ch;
30}
31
32bool
33__ns_samebinaryname (const unsigned char *a, const unsigned char *b)
34{
35 while (*a != 0 && *b != 0)
36 {
37 if (*a != *b)
38 /* Different label length. */
39 return false;
40 int labellen = *a;
41 ++a;
42 ++b;
43 for (int i = 0; i < labellen; ++i)
44 {
45 if (*a != *b && ascii_toupper (*a) != ascii_toupper (*b))
46 /* Different character in label. */
47 return false;
48 ++a;
49 ++b;
50 }
51 }
52
53 /* Match if both names are at the root label. */
54 return *a == 0 && *b == 0;
55}
56