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 } DNSLabelFlags;
  31
  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);
  36
  37 static inline int dns_name_parent(const char **name) {
  38         return dns_label_unescape(name, NULL, DNS_LABEL_MAX, 0);
  39 }
  40
  41 #if HAVE_LIBIDN
  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);
  44 #endif
  45
  46 int dns_name_concat(const char *a, const char *b, DNSLabelFlags flags, char **ret);
  47
  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);
  51 }
  52
  53 static inline int dns_name_is_valid(const char *s) {
  54         int r;
  55
  56         /* dns_name_normalize() verifies as a side effect */
  57         r = dns_name_normalize(s, 0, NULL);
  58         if (r == -EINVAL)
  59                 return 0;
  60         if (r < 0)
  61                 return r;
  62         return 1;
  63 }
  64
  65 static inline int dns_name_is_valid_ldh(const char *s) {
  66         int r;
  67
  68         r = dns_name_concat(s, NULL, DNS_LABEL_LDH|DNS_LABEL_NO_ESCAPES, NULL);
  69         if (r == -EINVAL)
  70                 return 0;
  71         if (r < 0)
  72                 return r;
  73         return 1;
  74 }
  75
  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;
  79
  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);
  84
  85 int dns_name_change_suffix(const char *name, const char *old_suffix, const char *new_suffix, char **ret);
  86
  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);
  89
  90 bool dns_name_is_root(const char *name);
  91 bool dns_name_is_single_label(const char *name);
  92
  93 int dns_name_to_wire_format(const char *domain, uint8_t *buffer, size_t len, bool canonical);
  94
  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);
  98
  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);
 101
 102 int dns_name_suffix(const char *name, unsigned n_labels, const char **ret);
 103 int dns_name_count_labels(const char *name);
 104
 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);
 107
 108 int dns_name_common_suffix(const char *a, const char *b, const char **ret);
 109
 110 int dns_name_apply_idna(const char *name, char **ret);
 111
 112 int dns_name_is_valid_or_address(const char *name);