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394085a34d
During packet parsing, only the binary name is available. If the name equality check is performed before conversion to text, we can sometimes skip the last step. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
56 lines
1.6 KiB
C
56 lines
1.6 KiB
C
/* Compare two binary domain names for quality.
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Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <arpa/nameser.h>
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#include <stdbool.h>
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/* Convert ASCII letters to upper case. */
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static inline int
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ascii_toupper (unsigned char ch)
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{
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if (ch >= 'a' && ch <= 'z')
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return ch - 'a' + 'A';
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else
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return ch;
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}
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bool
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__ns_samebinaryname (const unsigned char *a, const unsigned char *b)
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{
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while (*a != 0 && *b != 0)
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{
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if (*a != *b)
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/* Different label length. */
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return false;
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int labellen = *a;
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++a;
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++b;
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for (int i = 0; i < labellen; ++i)
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{
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if (*a != *b && ascii_toupper (*a) != ascii_toupper (*b))
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/* Different character in label. */
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return false;
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++a;
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++b;
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}
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}
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/* Match if both names are at the root label. */
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return *a == 0 && *b == 0;
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}
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