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/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "libdnssec/shared/dname.h"
#include "libdnssec/shared/shared.h"
#include "contrib/tolower.h"
/*!
* Get length of a domain name in wire format.
*/
size_t dname_length(const uint8_t *dname)
{
if (!dname) {
return 0;
}
const uint8_t *scan = dname;
uint8_t label_len;
do {
label_len = *scan;
scan += 1 + label_len;
} while (label_len > 0);
assert(scan > dname);
size_t length = scan - dname;
if (length > DNAME_MAX_LENGTH) {
return 0;
}
return length;
}
/*!
* Copy domain name in wire format.
*/
uint8_t *dname_copy(const uint8_t *dname)
{
if (!dname) {
return NULL;
}
size_t length = dname_length(dname);
if (length == 0) {
return NULL;
}
uint8_t *copy = malloc(length);
if (!copy) {
return NULL;
}
memmove(copy, dname, length);
return copy;
}
/*!
* Normalize dname label in-place.
*
* \return Number of processed bytes, 0 if we encounter the last label.
*/
static uint8_t normalize_label(uint8_t *label)
{
assert(label);
uint8_t len = *label;
if (len == 0 || len > DNAME_MAX_LABEL_LENGTH) {
return 0;
}
for (uint8_t *scan = label + 1, *end = scan + len; scan < end; scan++) {
*scan = knot_tolower(*scan);
}
return len + 1;
}
/*!
* Normalize domain name in wire format.
*/
void dname_normalize(uint8_t *dname)
{
if (!dname) {
return;
}
uint8_t read, *scan = dname;
do {
read = normalize_label(scan);
scan += read;
} while (read > 0);
}
/*!
* Compare dname labels case insensitively.
*/
static int label_casecmp(const uint8_t *a, const uint8_t *b, uint8_t len)
{
assert(a);
assert(b);
for (const uint8_t *a_end = a + len; a < a_end; a++, b++) {
if (knot_tolower(*a) != knot_tolower(*b)) {
return false;
}
}
return true;
}
/*!
* Check if two dnames are equal.
*/
bool dname_equal(const uint8_t *one, const uint8_t *two)
{
if (!one || !two) {
return false;
}
const uint8_t *scan_one = one;
const uint8_t *scan_two = two;
for (;;) {
if (*scan_one != *scan_two) {
return false;
}
uint8_t len = *scan_one;
if (len == 0) {
return true;
} else if (len > DNAME_MAX_LABEL_LENGTH) {
return false;
}
scan_one += 1;
scan_two += 1;
if (!label_casecmp(scan_one, scan_two, len)) {
return false;
}
scan_one += len;
scan_two += len;
}
return true;
}
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