/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd 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.
systemd 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 systemd; If not, see .
***/
#if HAVE_LIBIDN2
# include
#elif HAVE_LIBIDN
# include
# include
#endif
#include
#include
#include
#include
#include
#include "alloc-util.h"
#include "dns-domain.h"
#include "hashmap.h"
#include "hexdecoct.h"
#include "in-addr-util.h"
#include "macro.h"
#include "parse-util.h"
#include "string-util.h"
#include "strv.h"
#include "utf8.h"
int dns_label_unescape(const char **name, char *dest, size_t sz) {
const char *n;
char *d;
int r = 0;
assert(name);
assert(*name);
n = *name;
d = dest;
for (;;) {
if (*n == '.') {
n++;
break;
}
if (*n == 0)
break;
if (r >= DNS_LABEL_MAX)
return -EINVAL;
if (sz <= 0)
return -ENOBUFS;
if (*n == '\\') {
/* Escaped character */
n++;
if (*n == 0)
/* Ending NUL */
return -EINVAL;
else if (IN_SET(*n, '\\', '.')) {
/* Escaped backslash or dot */
if (d)
*(d++) = *n;
sz--;
r++;
n++;
} else if (n[0] >= '0' && n[0] <= '9') {
unsigned k;
/* Escaped literal ASCII character */
if (!(n[1] >= '0' && n[1] <= '9') ||
!(n[2] >= '0' && n[2] <= '9'))
return -EINVAL;
k = ((unsigned) (n[0] - '0') * 100) +
((unsigned) (n[1] - '0') * 10) +
((unsigned) (n[2] - '0'));
/* Don't allow anything that doesn't
* fit in 8bit. Note that we do allow
* control characters, as some servers
* (e.g. cloudflare) are happy to
* generate labels with them
* inside. */
if (k > 255)
return -EINVAL;
if (d)
*(d++) = (char) k;
sz--;
r++;
n += 3;
} else
return -EINVAL;
} else if ((uint8_t) *n >= (uint8_t) ' ' && *n != 127) {
/* Normal character */
if (d)
*(d++) = *n;
sz--;
r++;
n++;
} else
return -EINVAL;
}
/* Empty label that is not at the end? */
if (r == 0 && *n)
return -EINVAL;
/* More than one trailing dot? */
if (*n == '.')
return -EINVAL;
if (sz >= 1 && d)
*d = 0;
*name = n;
return r;
}
/* @label_terminal: terminal character of a label, updated to point to the terminal character of
* the previous label (always skipping one dot) or to NULL if there are no more
* labels. */
int dns_label_unescape_suffix(const char *name, const char **label_terminal, char *dest, size_t sz) {
const char *terminal;
int r;
assert(name);
assert(label_terminal);
assert(dest);
/* no more labels */
if (!*label_terminal) {
if (sz >= 1)
*dest = 0;
return 0;
}
terminal = *label_terminal;
assert(IN_SET(*terminal, 0, '.'));
/* Skip current terminal character (and accept domain names ending it ".") */
if (*terminal == 0)
terminal--;
if (terminal >= name && *terminal == '.')
terminal--;
/* Point name to the last label, and terminal to the preceding terminal symbol (or make it a NULL pointer) */
for (;;) {
if (terminal < name) {
/* Reached the first label, so indicate that there are no more */
terminal = NULL;
break;
}
/* Find the start of the last label */
if (*terminal == '.') {
const char *y;
unsigned slashes = 0;
for (y = terminal - 1; y >= name && *y == '\\'; y--)
slashes++;
if (slashes % 2 == 0) {
/* The '.' was not escaped */
name = terminal + 1;
break;
} else {
terminal = y;
continue;
}
}
terminal--;
}
r = dns_label_unescape(&name, dest, sz);
if (r < 0)
return r;
*label_terminal = terminal;
return r;
}
int dns_label_escape(const char *p, size_t l, char *dest, size_t sz) {
char *q;
/* DNS labels must be between 1 and 63 characters long. A
* zero-length label does not exist. See RFC 2182, Section
* 11. */
if (l <= 0 || l > DNS_LABEL_MAX)
return -EINVAL;
if (sz < 1)
return -ENOBUFS;
assert(p);
assert(dest);
q = dest;
while (l > 0) {
if (IN_SET(*p, '.', '\\')) {
/* Dot or backslash */
if (sz < 3)
return -ENOBUFS;
*(q++) = '\\';
*(q++) = *p;
sz -= 2;
} else if (IN_SET(*p, '_', '-') ||
(*p >= '0' && *p <= '9') ||
(*p >= 'a' && *p <= 'z') ||
(*p >= 'A' && *p <= 'Z')) {
/* Proper character */
if (sz < 2)
return -ENOBUFS;
*(q++) = *p;
sz -= 1;
} else {
/* Everything else */
if (sz < 5)
return -ENOBUFS;
*(q++) = '\\';
*(q++) = '0' + (char) ((uint8_t) *p / 100);
*(q++) = '0' + (char) (((uint8_t) *p / 10) % 10);
*(q++) = '0' + (char) ((uint8_t) *p % 10);
sz -= 4;
}
p++;
l--;
}
*q = 0;
return (int) (q - dest);
}
int dns_label_escape_new(const char *p, size_t l, char **ret) {
_cleanup_free_ char *s = NULL;
int r;
assert(p);
assert(ret);
if (l <= 0 || l > DNS_LABEL_MAX)
return -EINVAL;
s = new(char, DNS_LABEL_ESCAPED_MAX);
if (!s)
return -ENOMEM;
r = dns_label_escape(p, l, s, DNS_LABEL_ESCAPED_MAX);
if (r < 0)
return r;
*ret = TAKE_PTR(s);
return r;
}
#if HAVE_LIBIDN
int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max) {
_cleanup_free_ uint32_t *input = NULL;
size_t input_size, l;
const char *p;
bool contains_8bit = false;
char buffer[DNS_LABEL_MAX+1];
assert(encoded);
assert(decoded);
/* Converts an U-label into an A-label */
if (encoded_size <= 0)
return -EINVAL;
for (p = encoded; p < encoded + encoded_size; p++)
if ((uint8_t) *p > 127)
contains_8bit = true;
if (!contains_8bit) {
if (encoded_size > DNS_LABEL_MAX)
return -EINVAL;
return 0;
}
input = stringprep_utf8_to_ucs4(encoded, encoded_size, &input_size);
if (!input)
return -ENOMEM;
if (idna_to_ascii_4i(input, input_size, buffer, 0) != 0)
return -EINVAL;
l = strlen(buffer);
/* Verify that the result is not longer than one DNS label. */
if (l <= 0 || l > DNS_LABEL_MAX)
return -EINVAL;
if (l > decoded_max)
return -ENOBUFS;
memcpy(decoded, buffer, l);
/* If there's room, append a trailing NUL byte, but only then */
if (decoded_max > l)
decoded[l] = 0;
return (int) l;
}
int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max) {
size_t input_size, output_size;
_cleanup_free_ uint32_t *input = NULL;
_cleanup_free_ char *result = NULL;
uint32_t *output = NULL;
size_t w;
/* To be invoked after unescaping. Converts an A-label into an U-label. */
assert(encoded);
assert(decoded);
if (encoded_size <= 0 || encoded_size > DNS_LABEL_MAX)
return -EINVAL;
if (encoded_size < sizeof(IDNA_ACE_PREFIX)-1)
return 0;
if (memcmp(encoded, IDNA_ACE_PREFIX, sizeof(IDNA_ACE_PREFIX) -1) != 0)
return 0;
input = stringprep_utf8_to_ucs4(encoded, encoded_size, &input_size);
if (!input)
return -ENOMEM;
output_size = input_size;
output = newa(uint32_t, output_size);
idna_to_unicode_44i(input, input_size, output, &output_size, 0);
result = stringprep_ucs4_to_utf8(output, output_size, NULL, &w);
if (!result)
return -ENOMEM;
if (w <= 0)
return -EINVAL;
if (w > decoded_max)
return -ENOBUFS;
memcpy(decoded, result, w);
/* Append trailing NUL byte if there's space, but only then. */
if (decoded_max > w)
decoded[w] = 0;
return w;
}
#endif
int dns_name_concat(const char *a, const char *b, char **_ret) {
_cleanup_free_ char *ret = NULL;
size_t n = 0, allocated = 0;
const char *p;
bool first = true;
int r;
if (a)
p = a;
else if (b) {
p = b;
b = NULL;
} else
goto finish;
for (;;) {
char label[DNS_LABEL_MAX];
r = dns_label_unescape(&p, label, sizeof(label));
if (r < 0)
return r;
if (r == 0) {
if (*p != 0)
return -EINVAL;
if (b) {
/* Now continue with the second string, if there is one */
p = b;
b = NULL;
continue;
}
break;
}
if (_ret) {
if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
return -ENOMEM;
r = dns_label_escape(label, r, ret + n + !first, DNS_LABEL_ESCAPED_MAX);
if (r < 0)
return r;
if (!first)
ret[n] = '.';
} else {
char escaped[DNS_LABEL_ESCAPED_MAX];
r = dns_label_escape(label, r, escaped, sizeof(escaped));
if (r < 0)
return r;
}
if (!first)
n++;
else
first = false;
n += r;
}
finish:
if (n > DNS_HOSTNAME_MAX)
return -EINVAL;
if (_ret) {
if (n == 0) {
/* Nothing appended? If so, generate at least a single dot, to indicate the DNS root domain */
if (!GREEDY_REALLOC(ret, allocated, 2))
return -ENOMEM;
ret[n++] = '.';
} else {
if (!GREEDY_REALLOC(ret, allocated, n + 1))
return -ENOMEM;
}
ret[n] = 0;
*_ret = ret;
ret = NULL;
}
return 0;
}
void dns_name_hash_func(const void *s, struct siphash *state) {
const char *p = s;
int r;
assert(p);
for (;;) {
char label[DNS_LABEL_MAX+1];
r = dns_label_unescape(&p, label, sizeof(label));
if (r < 0)
break;
if (r == 0)
break;
ascii_strlower_n(label, r);
siphash24_compress(label, r, state);
siphash24_compress_byte(0, state); /* make sure foobar and foo.bar result in different hashes */
}
/* enforce that all names are terminated by the empty label */
string_hash_func("", state);
}
int dns_name_compare_func(const void *a, const void *b) {
const char *x, *y;
int r, q;
assert(a);
assert(b);
x = (const char *) a + strlen(a);
y = (const char *) b + strlen(b);
for (;;) {
char la[DNS_LABEL_MAX], lb[DNS_LABEL_MAX];
if (x == NULL && y == NULL)
return 0;
r = dns_label_unescape_suffix(a, &x, la, sizeof(la));
q = dns_label_unescape_suffix(b, &y, lb, sizeof(lb));
if (r < 0 || q < 0)
return r - q;
r = ascii_strcasecmp_nn(la, r, lb, q);
if (r != 0)
return r;
}
}
const struct hash_ops dns_name_hash_ops = {
.hash = dns_name_hash_func,
.compare = dns_name_compare_func
};
int dns_name_equal(const char *x, const char *y) {
int r, q;
assert(x);
assert(y);
for (;;) {
char la[DNS_LABEL_MAX], lb[DNS_LABEL_MAX];
r = dns_label_unescape(&x, la, sizeof(la));
if (r < 0)
return r;
q = dns_label_unescape(&y, lb, sizeof(lb));
if (q < 0)
return q;
if (r != q)
return false;
if (r == 0)
return true;
if (ascii_strcasecmp_n(la, lb, r) != 0)
return false;
}
}
int dns_name_endswith(const char *name, const char *suffix) {
const char *n, *s, *saved_n = NULL;
int r, q;
assert(name);
assert(suffix);
n = name;
s = suffix;
for (;;) {
char ln[DNS_LABEL_MAX], ls[DNS_LABEL_MAX];
r = dns_label_unescape(&n, ln, sizeof(ln));
if (r < 0)
return r;
if (!saved_n)
saved_n = n;
q = dns_label_unescape(&s, ls, sizeof(ls));
if (q < 0)
return q;
if (r == 0 && q == 0)
return true;
if (r == 0 && saved_n == n)
return false;
if (r != q || ascii_strcasecmp_n(ln, ls, r) != 0) {
/* Not the same, let's jump back, and try with the next label again */
s = suffix;
n = TAKE_PTR(saved_n);
}
}
}
int dns_name_startswith(const char *name, const char *prefix) {
const char *n, *p;
int r, q;
assert(name);
assert(prefix);
n = name;
p = prefix;
for (;;) {
char ln[DNS_LABEL_MAX], lp[DNS_LABEL_MAX];
r = dns_label_unescape(&p, lp, sizeof(lp));
if (r < 0)
return r;
if (r == 0)
return true;
q = dns_label_unescape(&n, ln, sizeof(ln));
if (q < 0)
return q;
if (r != q)
return false;
if (ascii_strcasecmp_n(ln, lp, r) != 0)
return false;
}
}
int dns_name_change_suffix(const char *name, const char *old_suffix, const char *new_suffix, char **ret) {
const char *n, *s, *saved_before = NULL, *saved_after = NULL, *prefix;
int r, q;
assert(name);
assert(old_suffix);
assert(new_suffix);
assert(ret);
n = name;
s = old_suffix;
for (;;) {
char ln[DNS_LABEL_MAX], ls[DNS_LABEL_MAX];
if (!saved_before)
saved_before = n;
r = dns_label_unescape(&n, ln, sizeof(ln));
if (r < 0)
return r;
if (!saved_after)
saved_after = n;
q = dns_label_unescape(&s, ls, sizeof(ls));
if (q < 0)
return q;
if (r == 0 && q == 0)
break;
if (r == 0 && saved_after == n) {
*ret = NULL; /* doesn't match */
return 0;
}
if (r != q || ascii_strcasecmp_n(ln, ls, r) != 0) {
/* Not the same, let's jump back, and try with the next label again */
s = old_suffix;
n = saved_after;
saved_after = saved_before = NULL;
}
}
/* Found it! Now generate the new name */
prefix = strndupa(name, saved_before - name);
r = dns_name_concat(prefix, new_suffix, ret);
if (r < 0)
return r;
return 1;
}
int dns_name_between(const char *a, const char *b, const char *c) {
/* Determine if b is strictly greater than a and strictly smaller than c.
We consider the order of names to be circular, so that if a is
strictly greater than c, we consider b to be between them if it is
either greater than a or smaller than c. This is how the canonical
DNS name order used in NSEC records work. */
if (dns_name_compare_func(a, c) < 0)
/*
a and c are properly ordered:
a<---b--->c
*/
return dns_name_compare_func(a, b) < 0 &&
dns_name_compare_func(b, c) < 0;
else
/*
a and c are equal or 'reversed':
<--b--c a----->
or:
<-----c a--b-->
*/
return dns_name_compare_func(b, c) < 0 ||
dns_name_compare_func(a, b) < 0;
}
int dns_name_reverse(int family, const union in_addr_union *a, char **ret) {
const uint8_t *p;
int r;
assert(a);
assert(ret);
p = (const uint8_t*) a;
if (family == AF_INET)
r = asprintf(ret, "%u.%u.%u.%u.in-addr.arpa", p[3], p[2], p[1], p[0]);
else if (family == AF_INET6)
r = asprintf(ret, "%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.ip6.arpa",
hexchar(p[15] & 0xF), hexchar(p[15] >> 4), hexchar(p[14] & 0xF), hexchar(p[14] >> 4),
hexchar(p[13] & 0xF), hexchar(p[13] >> 4), hexchar(p[12] & 0xF), hexchar(p[12] >> 4),
hexchar(p[11] & 0xF), hexchar(p[11] >> 4), hexchar(p[10] & 0xF), hexchar(p[10] >> 4),
hexchar(p[ 9] & 0xF), hexchar(p[ 9] >> 4), hexchar(p[ 8] & 0xF), hexchar(p[ 8] >> 4),
hexchar(p[ 7] & 0xF), hexchar(p[ 7] >> 4), hexchar(p[ 6] & 0xF), hexchar(p[ 6] >> 4),
hexchar(p[ 5] & 0xF), hexchar(p[ 5] >> 4), hexchar(p[ 4] & 0xF), hexchar(p[ 4] >> 4),
hexchar(p[ 3] & 0xF), hexchar(p[ 3] >> 4), hexchar(p[ 2] & 0xF), hexchar(p[ 2] >> 4),
hexchar(p[ 1] & 0xF), hexchar(p[ 1] >> 4), hexchar(p[ 0] & 0xF), hexchar(p[ 0] >> 4));
else
return -EAFNOSUPPORT;
if (r < 0)
return -ENOMEM;
return 0;
}
int dns_name_address(const char *p, int *family, union in_addr_union *address) {
int r;
assert(p);
assert(family);
assert(address);
r = dns_name_endswith(p, "in-addr.arpa");
if (r < 0)
return r;
if (r > 0) {
uint8_t a[4];
unsigned i;
for (i = 0; i < ELEMENTSOF(a); i++) {
char label[DNS_LABEL_MAX+1];
r = dns_label_unescape(&p, label, sizeof(label));
if (r < 0)
return r;
if (r == 0)
return -EINVAL;
if (r > 3)
return -EINVAL;
r = safe_atou8(label, &a[i]);
if (r < 0)
return r;
}
r = dns_name_equal(p, "in-addr.arpa");
if (r <= 0)
return r;
*family = AF_INET;
address->in.s_addr = htobe32(((uint32_t) a[3] << 24) |
((uint32_t) a[2] << 16) |
((uint32_t) a[1] << 8) |
(uint32_t) a[0]);
return 1;
}
r = dns_name_endswith(p, "ip6.arpa");
if (r < 0)
return r;
if (r > 0) {
struct in6_addr a;
unsigned i;
for (i = 0; i < ELEMENTSOF(a.s6_addr); i++) {
char label[DNS_LABEL_MAX+1];
int x, y;
r = dns_label_unescape(&p, label, sizeof(label));
if (r <= 0)
return r;
if (r != 1)
return -EINVAL;
x = unhexchar(label[0]);
if (x < 0)
return -EINVAL;
r = dns_label_unescape(&p, label, sizeof(label));
if (r <= 0)
return r;
if (r != 1)
return -EINVAL;
y = unhexchar(label[0]);
if (y < 0)
return -EINVAL;
a.s6_addr[ELEMENTSOF(a.s6_addr) - i - 1] = (uint8_t) y << 4 | (uint8_t) x;
}
r = dns_name_equal(p, "ip6.arpa");
if (r <= 0)
return r;
*family = AF_INET6;
address->in6 = a;
return 1;
}
return 0;
}
bool dns_name_is_root(const char *name) {
assert(name);
/* There are exactly two ways to encode the root domain name:
* as empty string, or with a single dot. */
return STR_IN_SET(name, "", ".");
}
bool dns_name_is_single_label(const char *name) {
int r;
assert(name);
r = dns_name_parent(&name);
if (r <= 0)
return false;
return dns_name_is_root(name);
}
/* Encode a domain name according to RFC 1035 Section 3.1, without compression */
int dns_name_to_wire_format(const char *domain, uint8_t *buffer, size_t len, bool canonical) {
uint8_t *label_length, *out;
int r;
assert(domain);
assert(buffer);
out = buffer;
do {
/* Reserve a byte for label length */
if (len <= 0)
return -ENOBUFS;
len--;
label_length = out;
out++;
/* Convert and copy a single label. Note that
* dns_label_unescape() returns 0 when it hits the end
* of the domain name, which we rely on here to encode
* the trailing NUL byte. */
r = dns_label_unescape(&domain, (char *) out, len);
if (r < 0)
return r;
/* Optionally, output the name in DNSSEC canonical
* format, as described in RFC 4034, section 6.2. Or
* in other words: in lower-case. */
if (canonical)
ascii_strlower_n((char*) out, (size_t) r);
/* Fill label length, move forward */
*label_length = r;
out += r;
len -= r;
} while (r != 0);
/* Verify the maximum size of the encoded name. The trailing
* dot + NUL byte account are included this time, hence
* compare against DNS_HOSTNAME_MAX + 2 (which is 255) this
* time. */
if (out - buffer > DNS_HOSTNAME_MAX + 2)
return -EINVAL;
return out - buffer;
}
static bool srv_type_label_is_valid(const char *label, size_t n) {
size_t k;
assert(label);
if (n < 2) /* Label needs to be at least 2 chars long */
return false;
if (label[0] != '_') /* First label char needs to be underscore */
return false;
/* Second char must be a letter */
if (!(label[1] >= 'A' && label[1] <= 'Z') &&
!(label[1] >= 'a' && label[1] <= 'z'))
return false;
/* Third and further chars must be alphanumeric or a hyphen */
for (k = 2; k < n; k++) {
if (!(label[k] >= 'A' && label[k] <= 'Z') &&
!(label[k] >= 'a' && label[k] <= 'z') &&
!(label[k] >= '0' && label[k] <= '9') &&
label[k] != '-')
return false;
}
return true;
}
bool dns_srv_type_is_valid(const char *name) {
unsigned c = 0;
int r;
if (!name)
return false;
for (;;) {
char label[DNS_LABEL_MAX];
/* This more or less implements RFC 6335, Section 5.1 */
r = dns_label_unescape(&name, label, sizeof(label));
if (r < 0)
return false;
if (r == 0)
break;
if (c >= 2)
return false;
if (!srv_type_label_is_valid(label, r))
return false;
c++;
}
return c == 2; /* exactly two labels */
}
bool dnssd_srv_type_is_valid(const char *name) {
return dns_srv_type_is_valid(name) &&
((dns_name_endswith(name, "_tcp") > 0) ||
(dns_name_endswith(name, "_udp") > 0)); /* Specific to DNS-SD. RFC 6763, Section 7 */
}
bool dns_service_name_is_valid(const char *name) {
size_t l;
/* This more or less implements RFC 6763, Section 4.1.1 */
if (!name)
return false;
if (!utf8_is_valid(name))
return false;
if (string_has_cc(name, NULL))
return false;
l = strlen(name);
if (l <= 0)
return false;
if (l > 63)
return false;
return true;
}
int dns_service_join(const char *name, const char *type, const char *domain, char **ret) {
char escaped[DNS_LABEL_ESCAPED_MAX];
_cleanup_free_ char *n = NULL;
int r;
assert(type);
assert(domain);
assert(ret);
if (!dns_srv_type_is_valid(type))
return -EINVAL;
if (!name)
return dns_name_concat(type, domain, ret);
if (!dns_service_name_is_valid(name))
return -EINVAL;
r = dns_label_escape(name, strlen(name), escaped, sizeof(escaped));
if (r < 0)
return r;
r = dns_name_concat(type, domain, &n);
if (r < 0)
return r;
return dns_name_concat(escaped, n, ret);
}
static bool dns_service_name_label_is_valid(const char *label, size_t n) {
char *s;
assert(label);
if (memchr(label, 0, n))
return false;
s = strndupa(label, n);
return dns_service_name_is_valid(s);
}
int dns_service_split(const char *joined, char **_name, char **_type, char **_domain) {
_cleanup_free_ char *name = NULL, *type = NULL, *domain = NULL;
const char *p = joined, *q = NULL, *d = NULL;
char a[DNS_LABEL_MAX], b[DNS_LABEL_MAX], c[DNS_LABEL_MAX];
int an, bn, cn, r;
unsigned x = 0;
assert(joined);
/* Get first label from the full name */
an = dns_label_unescape(&p, a, sizeof(a));
if (an < 0)
return an;
if (an > 0) {
x++;
/* If there was a first label, try to get the second one */
bn = dns_label_unescape(&p, b, sizeof(b));
if (bn < 0)
return bn;
if (bn > 0) {
x++;
/* If there was a second label, try to get the third one */
q = p;
cn = dns_label_unescape(&p, c, sizeof(c));
if (cn < 0)
return cn;
if (cn > 0)
x++;
} else
cn = 0;
} else
an = 0;
if (x >= 2 && srv_type_label_is_valid(b, bn)) {
if (x >= 3 && srv_type_label_is_valid(c, cn)) {
if (dns_service_name_label_is_valid(a, an)) {
/* OK, got . . . */
name = strndup(a, an);
if (!name)
return -ENOMEM;
type = strjoin(b, ".", c);
if (!type)
return -ENOMEM;
d = p;
goto finish;
}
} else if (srv_type_label_is_valid(a, an)) {
/* OK, got . . */
name = NULL;
type = strjoin(a, ".", b);
if (!type)
return -ENOMEM;
d = q;
goto finish;
}
}
name = NULL;
type = NULL;
d = joined;
finish:
r = dns_name_normalize(d, &domain);
if (r < 0)
return r;
if (_domain) {
*_domain = domain;
domain = NULL;
}
if (_type) {
*_type = type;
type = NULL;
}
if (_name) {
*_name = name;
name = NULL;
}
return 0;
}
static int dns_name_build_suffix_table(const char *name, const char*table[]) {
const char *p;
unsigned n = 0;
int r;
assert(name);
assert(table);
p = name;
for (;;) {
if (n > DNS_N_LABELS_MAX)
return -EINVAL;
table[n] = p;
r = dns_name_parent(&p);
if (r < 0)
return r;
if (r == 0)
break;
n++;
}
return (int) n;
}
int dns_name_suffix(const char *name, unsigned n_labels, const char **ret) {
const char* labels[DNS_N_LABELS_MAX+1];
int n;
assert(name);
assert(ret);
n = dns_name_build_suffix_table(name, labels);
if (n < 0)
return n;
if ((unsigned) n < n_labels)
return -EINVAL;
*ret = labels[n - n_labels];
return (int) (n - n_labels);
}
int dns_name_skip(const char *a, unsigned n_labels, const char **ret) {
int r;
assert(a);
assert(ret);
for (; n_labels > 0; n_labels--) {
r = dns_name_parent(&a);
if (r < 0)
return r;
if (r == 0) {
*ret = "";
return 0;
}
}
*ret = a;
return 1;
}
int dns_name_count_labels(const char *name) {
unsigned n = 0;
const char *p;
int r;
assert(name);
p = name;
for (;;) {
r = dns_name_parent(&p);
if (r < 0)
return r;
if (r == 0)
break;
if (n >= DNS_N_LABELS_MAX)
return -EINVAL;
n++;
}
return (int) n;
}
int dns_name_equal_skip(const char *a, unsigned n_labels, const char *b) {
int r;
assert(a);
assert(b);
r = dns_name_skip(a, n_labels, &a);
if (r <= 0)
return r;
return dns_name_equal(a, b);
}
int dns_name_common_suffix(const char *a, const char *b, const char **ret) {
const char *a_labels[DNS_N_LABELS_MAX+1], *b_labels[DNS_N_LABELS_MAX+1];
int n = 0, m = 0, k = 0, r, q;
assert(a);
assert(b);
assert(ret);
/* Determines the common suffix of domain names a and b */
n = dns_name_build_suffix_table(a, a_labels);
if (n < 0)
return n;
m = dns_name_build_suffix_table(b, b_labels);
if (m < 0)
return m;
for (;;) {
char la[DNS_LABEL_MAX], lb[DNS_LABEL_MAX];
const char *x, *y;
if (k >= n || k >= m) {
*ret = a_labels[n - k];
return 0;
}
x = a_labels[n - 1 - k];
r = dns_label_unescape(&x, la, sizeof(la));
if (r < 0)
return r;
y = b_labels[m - 1 - k];
q = dns_label_unescape(&y, lb, sizeof(lb));
if (q < 0)
return q;
if (r != q || ascii_strcasecmp_n(la, lb, r) != 0) {
*ret = a_labels[n - k];
return 0;
}
k++;
}
}
int dns_name_apply_idna(const char *name, char **ret) {
/* Return negative on error, 0 if not implemented, positive on success. */
#if HAVE_LIBIDN2
int r;
_cleanup_free_ char *t = NULL;
assert(name);
assert(ret);
r = idn2_lookup_u8((uint8_t*) name, (uint8_t**) &t,
IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL);
log_debug("idn2_lookup_u8: %s → %s", name, t);
if (r == IDN2_OK) {
if (!startswith(name, "xn--")) {
_cleanup_free_ char *s = NULL;
r = idn2_to_unicode_8z8z(t, &s, 0);
if (r != IDN2_OK) {
log_debug("idn2_to_unicode_8z8z(\"%s\") failed: %d/%s",
t, r, idn2_strerror(r));
return 0;
}
if (!streq_ptr(name, s)) {
log_debug("idn2 roundtrip failed: \"%s\" → \"%s\" → \"%s\", ignoring.",
name, t, s);
return 0;
}
}
*ret = t;
t = NULL;
return 1; /* *ret has been written */
}
log_debug("idn2_lookup_u8(\"%s\") failed: %d/%s", name, r, idn2_strerror(r));
if (r == IDN2_2HYPHEN)
/* The name has two hypens — forbidden by IDNA2008 in some cases */
return 0;
if (IN_SET(r, IDN2_TOO_BIG_DOMAIN, IDN2_TOO_BIG_LABEL))
return -ENOSPC;
return -EINVAL;
#elif HAVE_LIBIDN
_cleanup_free_ char *buf = NULL;
size_t n = 0, allocated = 0;
bool first = true;
int r, q;
assert(name);
assert(ret);
for (;;) {
char label[DNS_LABEL_MAX];
r = dns_label_unescape(&name, label, sizeof(label));
if (r < 0)
return r;
if (r == 0)
break;
q = dns_label_apply_idna(label, r, label, sizeof(label));
if (q < 0)
return q;
if (q > 0)
r = q;
if (!GREEDY_REALLOC(buf, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
return -ENOMEM;
r = dns_label_escape(label, r, buf + n + !first, DNS_LABEL_ESCAPED_MAX);
if (r < 0)
return r;
if (first)
first = false;
else
buf[n++] = '.';
n += r;
}
if (n > DNS_HOSTNAME_MAX)
return -EINVAL;
if (!GREEDY_REALLOC(buf, allocated, n + 1))
return -ENOMEM;
buf[n] = 0;
*ret = buf;
buf = NULL;
return 1;
#else
return 0;
#endif
}
int dns_name_is_valid_or_address(const char *name) {
/* Returns > 0 if the specified name is either a valid IP address formatted as string or a valid DNS name */
if (isempty(name))
return 0;
if (in_addr_from_string_auto(name, NULL, NULL) >= 0)
return 1;
return dns_name_is_valid(name);
}