1 /* SPDX-License-Identifier: LGPL-2.1+ */
10 #include "in-addr-util.h"
12 /* Length of a single label, with all escaping removed, excluding any trailing dot or NUL byte */
13 #define DNS_LABEL_MAX 63
15 /* Worst case length of a single label, with all escaping applied and room for a trailing NUL byte. */
16 #define DNS_LABEL_ESCAPED_MAX (DNS_LABEL_MAX*4+1)
18 /* Maximum length of a full hostname, consisting of a series of unescaped labels, and no trailing dot or NUL byte */
19 #define DNS_HOSTNAME_MAX 253
21 /* Maximum length of a full hostname, on the wire, including the final NUL byte */
22 #define DNS_WIRE_FORMAT_HOSTNAME_MAX 255
24 /* Maximum number of labels per valid hostname */
25 #define DNS_N_LABELS_MAX 127
27 typedef enum DNSLabelFlags
{
28 DNS_LABEL_LDH
= 1 << 0, /* Follow the "LDH" rule — only letters, digits, and internal hyphens. */
29 DNS_LABEL_NO_ESCAPES
= 1 << 1, /* Do not treat backslashes specially */
32 int dns_label_unescape(const char **name
, char *dest
, size_t sz
, DNSLabelFlags flags
);
33 int dns_label_unescape_suffix(const char *name
, const char **label_end
, char *dest
, size_t sz
);
34 int dns_label_escape(const char *p
, size_t l
, char *dest
, size_t sz
);
35 int dns_label_escape_new(const char *p
, size_t l
, char **ret
);
37 static inline int dns_name_parent(const char **name
) {
38 return dns_label_unescape(name
, NULL
, DNS_LABEL_MAX
, 0);
42 int dns_label_apply_idna(const char *encoded
, size_t encoded_size
, char *decoded
, size_t decoded_max
);
43 int dns_label_undo_idna(const char *encoded
, size_t encoded_size
, char *decoded
, size_t decoded_max
);
46 int dns_name_concat(const char *a
, const char *b
, DNSLabelFlags flags
, char **ret
);
48 static inline int dns_name_normalize(const char *s
, DNSLabelFlags flags
, char **ret
) {
49 /* dns_name_concat() normalizes as a side-effect */
50 return dns_name_concat(s
, NULL
, flags
, ret
);
53 static inline int dns_name_is_valid(const char *s
) {
56 /* dns_name_normalize() verifies as a side effect */
57 r
= dns_name_normalize(s
, 0, NULL
);
65 static inline int dns_name_is_valid_ldh(const char *s
) {
68 r
= dns_name_concat(s
, NULL
, DNS_LABEL_LDH
|DNS_LABEL_NO_ESCAPES
, NULL
);
76 void dns_name_hash_func(const char *s
, struct siphash
*state
);
77 int dns_name_compare_func(const char *a
, const char *b
);
78 extern const struct hash_ops dns_name_hash_ops
;
80 int dns_name_between(const char *a
, const char *b
, const char *c
);
81 int dns_name_equal(const char *x
, const char *y
);
82 int dns_name_endswith(const char *name
, const char *suffix
);
83 int dns_name_startswith(const char *name
, const char *prefix
);
85 int dns_name_change_suffix(const char *name
, const char *old_suffix
, const char *new_suffix
, char **ret
);
87 int dns_name_reverse(int family
, const union in_addr_union
*a
, char **ret
);
88 int dns_name_address(const char *p
, int *family
, union in_addr_union
*a
);
90 bool dns_name_is_root(const char *name
);
91 bool dns_name_is_single_label(const char *name
);
93 int dns_name_to_wire_format(const char *domain
, uint8_t *buffer
, size_t len
, bool canonical
);
95 bool dns_srv_type_is_valid(const char *name
);
96 bool dnssd_srv_type_is_valid(const char *name
);
97 bool dns_service_name_is_valid(const char *name
);
99 int dns_service_join(const char *name
, const char *type
, const char *domain
, char **ret
);
100 int dns_service_split(const char *joined
, char **name
, char **type
, char **domain
);
102 int dns_name_suffix(const char *name
, unsigned n_labels
, const char **ret
);
103 int dns_name_count_labels(const char *name
);
105 int dns_name_skip(const char *a
, unsigned n_labels
, const char **ret
);
106 int dns_name_equal_skip(const char *a
, unsigned n_labels
, const char *b
);
108 int dns_name_common_suffix(const char *a
, const char *b
, const char **ret
);
110 int dns_name_apply_idna(const char *name
, char **ret
);
112 int dns_name_is_valid_or_address(const char *name
);