1 files changed, 130 insertions, 0 deletions
diff --git a/src/rexmpp_dns.h b/src/rexmpp_dns.h
new file mode 100644
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--- /dev/null
+++ b/src/rexmpp_dns.h
@@ -0,0 +1,130 @@
+/**
+   @file rexmpp_dns.h
+   @brief DNS resolution
+   @author defanor <defanor@uberspace.net>
+   @date 2020
+   @copyright MIT license.
+
+*/
+
+
+#ifndef REXMPP_DNS_H
+#define REXMPP_DNS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "config.h"
+
+#include "rexmpp.h"
+
+/**
+   @brief DNS context.
+*/
+#if defined(USE_UNBOUND)
+#include <unbound.h>
+typedef struct ub_ctx* rexmpp_dns_ctx_t;
+/* struct rexmpp_dns_ctx { */
+/*   struct ub_ctx *ctx; */
+/* }; */
+#elif defined(USE_CARES)
+#include <ares.h>
+typedef ares_channel rexmpp_dns_ctx_t;
+/* struct rexmpp_dns_ctx { */
+/*   ares_channel channel; */
+/* }; */
+#else
+typedef void* rexmpp_dns_ctx_t;
+#endif
+
+/* typedef struct rexmpp_dns_ctx rexmpp_dns_ctx_t; */
+
+struct rexmpp_dns_srv {
+  uint16_t priority;
+  uint16_t weight;
+  uint16_t port;
+  char target[256];
+};
+
+typedef struct rexmpp_dns_srv rexmpp_dns_srv_t;
+
+/**
+   @brief DNS query result.
+*/
+struct rexmpp_dns_result {
+  /** @brief NULL-terminated array of data pointers. They contain
+      ::rexmpp_dns_srv for SRV lookups, host addresses for A and AAAA
+      ones. */
+  void **data;
+  /** @brief An array of data structure lengths. */
+  int *len;
+  /** @brief Whether the result was retrieved securely (that is,
+      verified with DNSSEC). */
+  bool secure;
+};
+
+typedef struct rexmpp_dns_result rexmpp_dns_result_t;
+
+/**
+   @brief Parses an SRV DNS RR's RDATA.
+   @param[in] in SRV record's RDATA.
+   @param[in] in_len Length of the input data in octets.
+   @param[out] out A structure to fill with data.
+   @returns 0 on success, non-zero on parsing failure.
+*/
+int
+rexmpp_parse_srv (char *in, int in_len, struct rexmpp_dns_srv *out);
+
+/**
+   @brief Frees a ::rexmpp_dns_result structure and its members.
+   @param[in] result A pointer to a ::rexmpp_dns_result structure.
+*/
+void rexmpp_dns_result_free (rexmpp_dns_result_t *result);
+
+/**
+   @brief Initializes a DNS resolver context.
+*/
+int rexmpp_dns_ctx_init (rexmpp_t *s);
+
+/**
+   @brief Cleans up the state that can be discarded between XMPP
+   connections, to be called from rexmpp_cleanup.
+*/
+void rexmpp_dns_ctx_cleanup (rexmpp_t *s);
+
+/**
+   @brief Deinitializes a DNS resolver context.
+*/
+void rexmpp_dns_ctx_deinit (rexmpp_t *s);
+
+/**
+   @brief Sets file descriptors to select/poll.
+*/
+int rexmpp_dns_fds (rexmpp_t *s, fd_set *read_fds, fd_set *write_fds);
+
+/**
+   @brief Reports timeouts.
+*/
+struct timespec * rexmpp_dns_timeout (rexmpp_t *s,
+                                      struct timespec *max_tv,
+                                      struct timespec *tv);
+
+typedef void (*dns_query_cb_t) (rexmpp_t *s, void *ptr, rexmpp_dns_result_t *result);
+
+/**
+   @brief Initiates a query.
+*/
+int rexmpp_dns_resolve (rexmpp_t *s,
+                        const char *query,
+                        int rrtype,
+                        int rrclass,
+                        void* ptr,
+                        dns_query_cb_t callback);
+
+/**
+   @brief Processes active queries, should be called based on the
+   reported timeouts and file descriptors.
+*/
+int rexmpp_dns_process (rexmpp_t *s, fd_set *read_fds, fd_set *write_fds);
+
+
+#endif