#include "mg_resolv.h"

=== API reference

enum mg_resolve_err {
  MG_RESOLVE_OK = 0,
  MG_RESOLVE_NO_ANSWERS = 1,
  MG_RESOLVE_EXCEEDED_RETRY_COUNT = 2,
  MG_RESOLVE_TIMEOUT = 3
};

typedef void (*mg_resolve_callback_t)(struct mg_dns_message *dns_message,
                                      void *user_data, enum mg_resolve_err);

struct mg_resolve_async_opts {
  const char *nameserver;
  int max_retries;    /* defaults to 2 if zero */
  int timeout;        /* in seconds; defaults to 5 if zero */
  int accept_literal; /* pseudo-resolve literal ipv4 and ipv6 addrs */
  int only_literal;   /* only resolves literal addrs; sync cb invocation */
  struct mg_connection **dns_conn; /* return DNS connection */
};

Options for mg_resolve_async_opt.

int mg_resolve_async(struct mg_mgr *mgr, const char *name, int query,
                     mg_resolve_callback_t cb, void *data);

See mg_resolve_async_opt()

void mg_set_nameserver(struct mg_mgr *mgr, const char *nameserver);

Set default DNS server

int mg_resolve_async_opt(struct mg_mgr *mgr, const char *name, int query,
                         mg_resolve_callback_t cb, void *data,
                         struct mg_resolve_async_opts opts);

Resolved a DNS name asynchronously.

Upon successful resolution, the user callback will be invoked with the full DNS response message and a pointer to the user's context data.

In case of timeout while performing the resolution the callback will receive a NULL msg.

The DNS answers can be extracted with mg_next_record and mg_dns_parse_record_data:

[source,c]

struct in_addr ina; struct mg_dns_resource_record *rr = mg_next_record(msg, MG_DNS_A_RECORD, NULL);

mg_dns_parse_record_data(msg, rr, &ina, sizeof(ina));

int mg_resolve_from_hosts_file(const char *host, union socket_address *usa);

Resolve a name from /etc/hosts.

Returns 0 on success, -1 on failure.