README
¶
DNS-SD
This library implements Multicast DNS and DNS-Based Service Discovery to provide zero-configuration operations. It lets you announce and find services in a specific link-local domain.
Usage
Create a mDNS responder
The following code creates a service with name "My Website._http._tcp.local." for the host "My Computer" which has the IP "192.168.0.123" on port "12345". The service is added to a responder.
service := dnssd.NewService("My Website", "_http._tcp.", "local.", "My Computer", []net.IP{net.ParseIP("192.168.0.123")}, 12345)
resp, _ := dnssd.NewResponder()
handle, _ := resp.Add(service)
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
resp.Respond(ctx)
If the service should be published on all available network interfaces, you can provide an empty host name and no IP addresses. The service will then get the local host name and IP addresses assigned to it.
service := dnssd.NewService("My Website", "_http._tcp.", "local.", "", nil, 12345)
When calling Respond the responder probes for the service instance name and host name to be unqiue in the network. Once probing is finished, the service will be announced.
Update TXT records
Once a service is added to a responder, you have to use the handle object to update properties.
handle.UpdateText(map[string]string{"key1": "value1", "key2": "value2"}, resp)
Examples
There are examples in the _cmd directory to register services, resolve service instances and to browse for service types.
Conformance
This library passes the multicast DNS tests of Apple's Bonjour Conformance Test.
TODO
- Support negative responses (RFC6762 6.1)
- Handle txt records case insensitive
- Remove outdated services from cache regularly
- Make sure that hostnames are FQDNs
Contact
Matthias Hochgatterer
Github: https://github.com/brutella
Twitter: https://twitter.com/brutella
License
dnssd is available under the MIT license. See the LICENSE file for more info.
Documentation
¶
Index ¶
- Variables
- func A(srv Service, iface *net.Interface) []*dns.A
- func AAAA(srv Service, iface *net.Interface) []*dns.AAAA
- func DNSSDServicesPTR(srv Service) *dns.PTR
- func LookupType(ctx context.Context, service string, add AddServiceFunc, rmv RmvServiceFunc) (err error)
- func NSEC(rr dns.RR, srv Service, iface *net.Interface) *dns.NSEC
- func PTR(srv Service) *dns.PTR
- func SRV(srv Service) *dns.SRV
- func TXT(srv Service) *dns.TXT
- type AddServiceFunc
- type Cache
- type MDNSConn
- type Query
- type ReadFunc
- type Request
- type Responder
- type Response
- type RmvServiceFunc
- type Service
- func LookupInstance(ctx context.Context, instance string) (srv Service, err error)
- func NewService(name, typ, domain, host string, ips []net.IP, port int) Service
- func ProbeService(ctx context.Context, srv Service) (Service, error)
- func ReprobeService(ctx context.Context, srv Service) (Service, error)
- func (srv Service) Copy() *Service
- func (srv Service) Equal(other Service) bool
- func (srv Service) Hostname() string
- func (srv Service) ServiceInstanceName() string
- func (srv Service) ServiceName() string
- func (srv Service) ServicesMetaQueryName() string
- func (srv *Service) SetHostname(hostname string)
- type ServiceHandle
Constants ¶
This section is empty.
Variables ¶
var ( IPv4LinkLocalMulticast = net.ParseIP("224.0.0.251") IPv6LinkLocalMulticast = net.ParseIP("ff02::fb") AddrIPv4LinkLocalMulticast = &net.UDPAddr{ IP: IPv4LinkLocalMulticast, Port: 5353, } AddrIPv6LinkLocalMulticast = &net.UDPAddr{ IP: IPv6LinkLocalMulticast, Port: 5353, } TtlDefault uint32 = 75 * 60 // Default ttl for mDNS resource records TtlHostname uint32 = 120 // TTL for mDNS resource records containing the host name )
var DefaultResponder, _ = NewResponder()
Functions ¶
func DNSSDServicesPTR ¶
func LookupType ¶
func LookupType(ctx context.Context, service string, add AddServiceFunc, rmv RmvServiceFunc) (err error)
Types ¶
type AddServiceFunc ¶
type AddServiceFunc func(Service)
type MDNSConn ¶
type MDNSConn interface {
// SendQuery sends a mDNS query.
SendQuery(q *Query) error
// SendResponse sends a mDNS response
SendResponse(resp *Response) error
// Read returns a channel which receives mDNS messages
Read(ctx context.Context) <-chan *Request
// Close closes the connection
Close()
}
MDNSConn represents a mDNS connection. It encapsulates an IPv4 and IPv6 UDP connection.
func NewMDNSConn ¶
type Request ¶
type Request struct {
// contains filtered or unexported fields
}
Request represents an incoming mDNS message
type Responder ¶
type Responder interface {
// Add adds a service to the responder.
// Use the returned service handle to update service properties.
Add(srv Service) (ServiceHandle, error)
// Remove removes the service associated with the service handle from the responder.
Remove(srv ServiceHandle)
// Respond makes the receiver announcing and managing services.
Respond(ctx context.Context) error
}
Responder represents a mDNS responder.
func NewResponder ¶
type Response ¶
type Response struct {
// contains filtered or unexported fields
}
Response is a mDNS response
type RmvServiceFunc ¶
type RmvServiceFunc func(Service)
type Service ¶
type Service struct {
Name string // e.g. Accessory (no trailing dot)
Type string // e.g. _hap._tcp.
Domain string // e.g. local.
Host string // e.g. MacBook (no trailing dot)
Text map[string]string
Ttl time.Duration // Original time to live
Port int
IPs []net.IP
IfaceIPs map[string][]net.IP
// contains filtered or unexported fields
}
Service represents a DNS-SD service instance
func LookupInstance ¶
LookupInstance resolves a service by its service instance name.
func ProbeService ¶
ProbeService probes for the hostname and service instance name of srv. If err == nil, the returned service is verified to be unique on the local network.
Source Files
Directories