/
a.go
115 lines (92 loc) · 2.67 KB
/
a.go
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package dns
import (
"fmt"
"net"
mdns "github.com/miekg/dns"
)
var TypeA uint16 = 1
// QueryA ask the server and returns a slice of net.IP.
// The answer slice will be nil in case of error.
//
// The other record types are ignored.
func (s *Server) QueryA(name string) ([]net.IP, error) {
rr, err := s.query(name, TypeA)
if err != nil {
return nil, err
}
r := make([]net.IP, 0, len(rr))
for i := range rr {
switch v := rr[i].(type) {
case *mdns.A:
r = append(r, v.A)
case *mdns.CNAME:
// Ignore CNAME
continue
case *mdns.DNAME:
// Ignore DNAME
continue
default:
return nil, fmt.Errorf("unknown type: %T", v)
}
}
return r, nil
}
// QueryA ask a random server from servers and returns a slice of net.IP.
// The answer slice will be nil in case of error.
//
// The other record types are ignored.
func (s *Servers) QueryA(name string) ([]net.IP, error) {
return s.Get(-1).QueryA(name)
}
// QueryA ask a random server from DefaultServers and returns a slice of net.IP.
// The answer slice will be nil in case of error.
//
// The other record types are ignored.
func QueryA(name string) ([]net.IP, error) {
return DefaultServers.QueryA(name)
}
// TryQueryA asks the servers for type A. If any error occurred, retries with next server (except if error is NXDOMAIN).
//
// In case of error, the answer will be nil and return ErrX or any unknown error.
//
// The first used server is random. The other record types are ignored.
func (s *Servers) TryQueryA(name string) ([]net.IP, error) {
rr, err := s.TryQuery(name, TypeA)
if err != nil {
return nil, err
}
r := make([]net.IP, 0, len(rr))
for i := range rr {
switch v := rr[i].(type) {
case *mdns.A:
r = append(r, v.A)
case *mdns.CNAME:
// Ignore CNAME
continue
case *mdns.DNAME:
// Ignore DNAME
continue
default:
return nil, fmt.Errorf("unknown type: %T", v)
}
}
return r, nil
}
// TryQueryA asks the DefaultServers for type A. If any error occurred, retries with next server (except if error is NXDOMAIN).
//
// In case of error, the answer will be nil and return ErrX or any unknown error.
//
// The first used server is random. The other record types are ignored.
func TryQueryA(name string) ([]net.IP, error) {
return DefaultServers.TryQueryA(name)
}
// IsSetA checks whether an A type record set for name.
// NXDOMAIN is not an error here, because it means "not found".
func (s *Servers) IsSetA(name string) (bool, error) {
return s.IsSet(name, TypeA)
}
// IsSetA checks whether an A type record set for name using the DefaultServers.
// NXDOMAIN is not an error here, because it means "not found".
func IsSetA(name string) (bool, error) {
return DefaultServers.IsSetA(name)
}