src/shared/dns-domain.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include <errno.h>
   5 #include <stdbool.h>
   6 #include <stddef.h>
   7 #include <stdint.h>
   8
   9 #include "hashmap.h"
  10 #include "in-addr-util.h"
  11
  12 /* Length of a single label, with all escaping removed, excluding any trailing dot or NUL byte */
  13 #define DNS_LABEL_MAX 63
  14
  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)
  17
  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
  20
  21 /* Maximum length of a full hostname, on the wire, including the final NUL byte */
  22 #define DNS_WIRE_FORMAT_HOSTNAME_MAX 255
  23
  24 /* Maximum number of labels per valid hostname */
  25 #define DNS_N_LABELS_MAX 127
  26
  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 */
  30         DNS_LABEL_LEAVE_TRAILING_DOT = 1 << 2, /* Leave trailing dot in place */
  31 } DNSLabelFlags;
  32
  33 int dns_label_unescape(const char **name, char *dest, size_t sz, DNSLabelFlags flags);
  34 int dns_label_unescape_suffix(const char *name, const char **label_end, char *dest, size_t sz);
  35 int dns_label_escape(const char *p, size_t l, char *dest, size_t sz);
  36 int dns_label_escape_new(const char *p, size_t l, char **ret);
  37
  38 static inline int dns_name_parent(const char **name) {
  39         return dns_label_unescape(name, NULL, DNS_LABEL_MAX, 0);
  40 }
  41
  42 #if HAVE_LIBIDN
  43 int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
  44 int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
  45 #endif
  46
  47 int dns_name_concat(const char *a, const char *b, DNSLabelFlags flags, char **ret);
  48
  49 static inline int dns_name_normalize(const char *s, DNSLabelFlags flags, char **ret) {
  50         /* dns_name_concat() normalizes as a side-effect */
  51         return dns_name_concat(s, NULL, flags, ret);
  52 }
  53
  54 static inline int dns_name_is_valid(const char *s) {
  55         int r;
  56
  57         /* dns_name_normalize() verifies as a side effect */
  58         r = dns_name_normalize(s, 0, NULL);
  59         if (r == -EINVAL)
  60                 return 0;
  61         if (r < 0)
  62                 return r;
  63         return 1;
  64 }
  65
  66 static inline int dns_name_is_valid_ldh(const char *s) {
  67         int r;
  68
  69         r = dns_name_concat(s, NULL, DNS_LABEL_LDH|DNS_LABEL_NO_ESCAPES, NULL);
  70         if (r == -EINVAL)
  71                 return 0;
  72         if (r < 0)
  73                 return r;
  74         return 1;
  75 }
  76
  77 void dns_name_hash_func(const char *s, struct siphash *state);
  78 int dns_name_compare_func(const char *a, const char *b);
  79 extern const struct hash_ops dns_name_hash_ops;
  80
  81 int dns_name_between(const char *a, const char *b, const char *c);
  82 int dns_name_equal(const char *x, const char *y);
  83 int dns_name_endswith(const char *name, const char *suffix);
  84 int dns_name_startswith(const char *name, const char *prefix);
  85
  86 int dns_name_change_suffix(const char *name, const char *old_suffix, const char *new_suffix, char **ret);
  87
  88 int dns_name_reverse(int family, const union in_addr_union *a, char **ret);
  89 int dns_name_address(const char *p, int *family, union in_addr_union *a);
  90
  91 bool dns_name_is_root(const char *name);
  92 bool dns_name_is_single_label(const char *name);
  93
  94 int dns_name_to_wire_format(const char *domain, uint8_t *buffer, size_t len, bool canonical);
  95
  96 bool dns_srv_type_is_valid(const char *name);
  97 bool dnssd_srv_type_is_valid(const char *name);
  98 bool dns_service_name_is_valid(const char *name);
  99
 100 int dns_service_join(const char *name, const char *type, const char *domain, char **ret);
 101 int dns_service_split(const char *joined, char **name, char **type, char **domain);
 102
 103 int dns_name_suffix(const char *name, unsigned n_labels, const char **ret);
 104 int dns_name_count_labels(const char *name);
 105
 106 int dns_name_skip(const char *a, unsigned n_labels, const char **ret);
 107 int dns_name_equal_skip(const char *a, unsigned n_labels, const char *b);
 108
 109 int dns_name_common_suffix(const char *a, const char *b, const char **ret);
 110
 111 int dns_name_apply_idna(const char *name, char **ret);
 112
 113 int dns_name_is_valid_or_address(const char *name);
 114
 115 int dns_name_dot_suffixed(const char *name);