glibc/resolv/ns_samebinaryname.c

56 lines
1.6 KiB
C

/* Compare two binary domain names for quality.
Copyright (C) 2022-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <arpa/nameser.h>
#include <stdbool.h>
/* Convert ASCII letters to upper case. */
static inline int
ascii_toupper (unsigned char ch)
{
if (ch >= 'a' && ch <= 'z')
return ch - 'a' + 'A';
else
return ch;
}
bool
__ns_samebinaryname (const unsigned char *a, const unsigned char *b)
{
while (*a != 0 && *b != 0)
{
if (*a != *b)
/* Different label length. */
return false;
int labellen = *a;
++a;
++b;
for (int i = 0; i < labellen; ++i)
{
if (*a != *b && ascii_toupper (*a) != ascii_toupper (*b))
/* Different character in label. */
return false;
++a;
++b;
}
}
/* Match if both names are at the root label. */
return *a == 0 && *b == 0;
}