server

Documentation

Overview

Package server provides functions to create and manage DNS server instances

Index

• Variables
• type AcceptAction
  • func DefaultAcceptFunc(h dns.Header) AcceptAction
  • func (a AcceptAction) String() string
• type AcceptFunc
• type OptionsFunc
  • func WithAcceptFunc(a AcceptFunc) OptionsFunc
  • func WithCache(c cache.Cache) OptionsFunc
  • func WithCollector(c collector.Collector) OptionsFunc
  • func WithFilter(f filter.Engine) OptionsFunc
  • func WithPacker(p packers.Packer) OptionsFunc
  • func WithReader(r dio.Reader) OptionsFunc
  • func WithResolver(r resolver.Resolver) OptionsFunc
  • func WithUnpacker(u packers.Unpacker) OptionsFunc
  • func WithWriter(w dio.Writer) OptionsFunc
• type Server
  • func New(cfg *config.Config) *Server
  • func (s *Server) Configure(opts ...OptionsFunc) error
  • func (s *Server) Defaults()
  • func (s *Server) Run() error
  • func (s *Server) Shutdown()
  • func (s *Server) Wait()

Variables

var (
	ErrServerAlreadyRunning = errors.New("server already running")
	ErrUnexpectedConnection = errors.New("unexpected connection")
	ErrNoSuchNetwork        = errors.New("no such network")
	ErrNoQuestions          = errors.New("no questions")
)

Types

type AcceptAction

type AcceptAction int

const (
	AcceptMessage AcceptAction = iota
	RejectMessage
	IgnoreMessage
	NoImplMessage
)

func DefaultAcceptFunc

func DefaultAcceptFunc(h dns.Header) AcceptAction

func (AcceptAction) String

func (a AcceptAction) String() string

type AcceptFunc

type AcceptFunc func(dns.Header) AcceptAction

type OptionsFunc

type OptionsFunc func(*Server) error

func WithAcceptFunc

func WithAcceptFunc(a AcceptFunc) OptionsFunc

func WithCache

func WithCache(c cache.Cache) OptionsFunc

func WithCollector

func WithCollector(c collector.Collector) OptionsFunc

func WithFilter

func WithFilter(f filter.Engine) OptionsFunc

func WithPacker

func WithPacker(p packers.Packer) OptionsFunc

func WithReader

func WithReader(r dio.Reader) OptionsFunc

func WithResolver

func WithResolver(r resolver.Resolver) OptionsFunc

func WithUnpacker

func WithUnpacker(u packers.Unpacker) OptionsFunc

func WithWriter

func WithWriter(w dio.Writer) OptionsFunc

type Server

type Server struct {
	// The address the server is running on (default: 0.0.0.0)
	Address net.IP

	// Network the server is using (default: udp)
	Network string

	// Port the server is listening on (default: 53)
	Port int

	// If the server is running in TCP mode, this listener
	// listens for incoming DNS messages
	TCPListener *net.TCPListener

	// If the server us running in UDP mode, this listener
	// listens for incoming UDP messages
	UDPListener *net.UDPConn

	// Logger is a light-weight wrapper around zap.Logger which
	// allows to the server (and all sub-components) to write
	// structured and leveled logs to one or multiple files
	Logger *logger.Logger

	// Reader implements the Reader interface to read
	// incoming TCP and UDP messages
	Reader dio.Reader

	// Writer implements the Writer interface to write
	// outgoing TCP and UDP messages
	Writer dio.Writer

	// Unpacker implements the Unpacker interface to unwrap
	// DNS messages
	Unpacker packers.Unpacker

	// Packer implements the Packer interface to pack
	// DNS messages
	Packer packers.Packer

	// Filter implements the Filter interface to enable DNS
	// filtering
	Filter filter.Engine

	// Cache implements the Cache interface to store record
	// data in memory for a specified TTL
	Cache cache.Cache

	// RecordStore implements the RecordStore interface to get and set
	// record data. A store can be anything, e.g. a file or
	// a database. The store has access to a cache instance
	// which stores record data in memory. The default store
	// does not use the cache as it is implemented as a
	// in-memory tree structure
	RecordStore store.Store

	// Resolver implements the Resolver interface to resolve
	// unknown domain names either iteratively or recursively.
	// After resolving the record data should get stored in
	// the cache
	Resolver resolver.Resolver

	// Collector implements the Collector interface to collect
	// query logs
	Collector collector.Collector

	// UDPMessageSize is the default message size to create
	// the temporary slice of bytes within the messageList
	// pool
	UDPMessageSize int

	// AncillarySize is the maximum size required to store
	// ancillary data of UDP messages. This is culculated
	// beforehand to avoid re-calculation of the same size
	// over and over again
	AncillarySize int

	// AcceptFunc validates if the DNS message should be
	// accepted or rejected (when sending invalid data)
	AcceptFunc AcceptFunc
	// contains filtered or unexported fields
}

Server describes options for running a DNS server

func New

func New(cfg *config.Config) *Server

New creates a new DNS server instance

func (*Server) Configure

func (s *Server) Configure(opts ...OptionsFunc) error

Configure configures custom server components

func (*Server) Defaults

func (s *Server) Defaults()

Defaults initializes default server parameters and checks if all neccesary components are registered. If not it falls back to defaults. This functions expects a validated config.Config

func (*Server) Run

func (s *Server) Run() error

Run starts the listen / respond loop of DNS messages

func (*Server) Shutdown

func (s *Server) Shutdown()

func (*Server) Wait

func (s *Server) Wait()