dnsserver

Documentation

Overview

Package DNS server implements all the interfaces from Caddy, so that CoreDNS can be a servertype plugin.

Index

• Constants
• Variables
• func DefaultErrorFunc(w dns.ResponseWriter, r *dns.Msg, rcode int)
• func RegisterDevDirective(name, before string)
• type Config
  • func GetConfig(c *caddy.Controller) *Config
  • func (c *Config) AddMiddleware(m middleware.Middleware)
• type Server
  • func NewServer(addr string, group []*Config) (*Server, error)
  • func (s *Server) Listen() (net.Listener, error)
  • func (s *Server) ListenPacket() (net.PacketConn, error)
  • func (s *Server) OnStartupComplete()
  • func (s *Server) Serve(l net.Listener) error
  • func (s *Server) ServeDNS(w dns.ResponseWriter, r *dns.Msg)
  • func (s *Server) ServePacket(p net.PacketConn) error
  • func (s *Server) Stop() (err error)

Constants

const (
	// DefaultPort is the default port.
	DefaultPort = "2053"
)

Variables

var (
	// Port is the site port
	Port = DefaultPort

	// GracefulTimeout is the maximum duration of a graceful shutdown.
	GracefulTimeout time.Duration

	// Quiet mode will not show any informative output on initialization.
	Quiet bool
)

These "soft defaults" are configurable by command line flags, etc.

Functions

func DefaultErrorFunc

func DefaultErrorFunc(w dns.ResponseWriter, r *dns.Msg, rcode int)

DefaultErrorFunc responds to an DNS request with an error.

func RegisterDevDirective

func RegisterDevDirective(name, before string)

RegisterDevDirective splices name into the list of directives immediately before another directive. This function is ONLY for plugin development purposes! NEVER use it for a plugin that you are not currently building. If before is empty, the directive will be appended to the end of the list.

It is imperative that directives execute in the proper order, and hard-coding the list of directives guarantees a correct, absolute order every time. This function is convenient when developing a plugin, but it does not guarantee absolute ordering. Multiple plugins registering directives with this function will lead to non- deterministic builds and buggy software.

Directive names must be lower-cased and unique. Any errors here are fatal, and even successful calls print a message to stdout as a reminder to use it only in development.

Types

type Config

type Config struct {
	// The zone of the site.
	Zone string

	// The hostname to bind listener to, defaults to the wildcard address
	ListenHost string

	// The port to listen on.
	Port string

	// Middleware stack.
	Middleware []middleware.Middleware
	// contains filtered or unexported fields
}

Config configuration for a single server.

func GetConfig

func GetConfig(c *caddy.Controller) *Config

GetConfig gets the Config that corresponds to c. If none exist nil is returned.

func (*Config) AddMiddleware

func (c *Config) AddMiddleware(m middleware.Middleware)

AddMiddleware adds a middleware to a site's middleware stack.

type Server

type Server struct {
	Addr string // Address we listen on
	// contains filtered or unexported fields
}

Server represents an instance of a server, which serves DNS requests at a particular address (host and port). A server is capable of serving numerous zones on the same address and the listener may be stopped for graceful termination (POSIX only).

func NewServer

func NewServer(addr string, group []*Config) (*Server, error)

NewServer returns a new CoreDNS server and compiles all middleware in to it.

func (*Server) Listen

func (s *Server) Listen() (net.Listener, error)

Listen implements caddy.TCPServer interface.

func (*Server) ListenPacket

func (s *Server) ListenPacket() (net.PacketConn, error)

ListenPacket implements caddy.UDPServer interface.

func (*Server) OnStartupComplete

func (s *Server) OnStartupComplete()

OnStartupComplete lists the sites served by this server and any relevant information, assuming Quiet == false.

func (*Server) Serve

func (s *Server) Serve(l net.Listener) error

Serve starts the server with an existing listener. It blocks until the server stops.

func (*Server) ServeDNS

func (s *Server) ServeDNS(w dns.ResponseWriter, r *dns.Msg)

ServeDNS is the entry point for every request to the address that s is bound to. It acts as a multiplexer for the requests zonename as defined in the request so that the correct zone (configuration and middleware stack) will handle the request.

func (*Server) ServePacket

func (s *Server) ServePacket(p net.PacketConn) error

ServePacket starts the server with an existing packetconn. It blocks until the server stops.

func (*Server) Stop

func (s *Server) Stop() (err error)

Stop stops the server. It blocks until the server is totally stopped. On POSIX systems, it will wait for connections to close (up to a max timeout of a few seconds); on Windows it will close the listener immediately.