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/**
@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 "config.h"
#include "rexmpp.h"
/**
@brief DNS context.
*/
#if defined(USE_UNBOUND)
#include <unbound.h>
struct rexmpp_dns_ctx {
struct ub_ctx *ctx;
};
#elif defined(USE_CARES)
#include <ares.h>
struct rexmpp_dns_ctx {
ares_channel channel;
};
#else
struct rexmpp_dns_ctx {
int dummy;
};
#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). */
int 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 timeval * rexmpp_dns_timeout (rexmpp_t *s,
struct timeval *max_tv,
struct timeval *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
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