1 files changed, 112 insertions, 0 deletions
diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h
new file mode 100644
index 0000000..6ed512c
--- /dev/null
+++ b/src/shared/dns-domain.h
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "hashmap.h"
+#include "in-addr-util.h"
+
+/* Length of a single label, with all escaping removed, excluding any trailing dot or NUL byte */
+#define DNS_LABEL_MAX 63
+
+/* Worst case length of a single label, with all escaping applied and room for a trailing NUL byte. */
+#define DNS_LABEL_ESCAPED_MAX (DNS_LABEL_MAX*4+1)
+
+/* Maximum length of a full hostname, consisting of a series of unescaped labels, and no trailing dot or NUL byte */
+#define DNS_HOSTNAME_MAX 253
+
+/* Maximum length of a full hostname, on the wire, including the final NUL byte */
+#define DNS_WIRE_FORMAT_HOSTNAME_MAX 255
+
+/* Maximum number of labels per valid hostname */
+#define DNS_N_LABELS_MAX 127
+
+typedef enum DNSLabelFlags {
+        DNS_LABEL_LDH        = 1 << 0, /* Follow the "LDH" rule — only letters, digits, and internal hyphens. */
+        DNS_LABEL_NO_ESCAPES = 1 << 1, /* Do not treat backslashes specially */
+} DNSLabelFlags;
+
+int dns_label_unescape(const char **name, char *dest, size_t sz, DNSLabelFlags flags);
+int dns_label_unescape_suffix(const char *name, const char **label_end, char *dest, size_t sz);
+int dns_label_escape(const char *p, size_t l, char *dest, size_t sz);
+int dns_label_escape_new(const char *p, size_t l, char **ret);
+
+static inline int dns_name_parent(const char **name) {
+        return dns_label_unescape(name, NULL, DNS_LABEL_MAX, 0);
+}
+
+#if HAVE_LIBIDN
+int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
+int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
+#endif
+
+int dns_name_concat(const char *a, const char *b, DNSLabelFlags flags, char **ret);
+
+static inline int dns_name_normalize(const char *s, DNSLabelFlags flags, char **ret) {
+        /* dns_name_concat() normalizes as a side-effect */
+        return dns_name_concat(s, NULL, flags, ret);
+}
+
+static inline int dns_name_is_valid(const char *s) {
+        int r;
+
+        /* dns_name_normalize() verifies as a side effect */
+        r = dns_name_normalize(s, 0, NULL);
+        if (r == -EINVAL)
+                return 0;
+        if (r < 0)
+                return r;
+        return 1;
+}
+
+static inline int dns_name_is_valid_ldh(const char *s) {
+        int r;
+
+        r = dns_name_concat(s, NULL, DNS_LABEL_LDH|DNS_LABEL_NO_ESCAPES, NULL);
+        if (r == -EINVAL)
+                return 0;
+        if (r < 0)
+                return r;
+        return 1;
+}
+
+void dns_name_hash_func(const char *s, struct siphash *state);
+int dns_name_compare_func(const char *a, const char *b);
+extern const struct hash_ops dns_name_hash_ops;
+
+int dns_name_between(const char *a, const char *b, const char *c);
+int dns_name_equal(const char *x, const char *y);
+int dns_name_endswith(const char *name, const char *suffix);
+int dns_name_startswith(const char *name, const char *prefix);
+
+int dns_name_change_suffix(const char *name, const char *old_suffix, const char *new_suffix, char **ret);
+
+int dns_name_reverse(int family, const union in_addr_union *a, char **ret);
+int dns_name_address(const char *p, int *family, union in_addr_union *a);
+
+bool dns_name_is_root(const char *name);
+bool dns_name_is_single_label(const char *name);
+
+int dns_name_to_wire_format(const char *domain, uint8_t *buffer, size_t len, bool canonical);
+
+bool dns_srv_type_is_valid(const char *name);
+bool dnssd_srv_type_is_valid(const char *name);
+bool dns_service_name_is_valid(const char *name);
+
+int dns_service_join(const char *name, const char *type, const char *domain, char **ret);
+int dns_service_split(const char *joined, char **name, char **type, char **domain);
+
+int dns_name_suffix(const char *name, unsigned n_labels, const char **ret);
+int dns_name_count_labels(const char *name);
+
+int dns_name_skip(const char *a, unsigned n_labels, const char **ret);
+int dns_name_equal_skip(const char *a, unsigned n_labels, const char *b);
+
+int dns_name_common_suffix(const char *a, const char *b, const char **ret);
+
+int dns_name_apply_idna(const char *name, char **ret);
+
+int dns_name_is_valid_or_address(const char *name);