dns

Documentation

Index

• func DNSDialer(port int) func(ctx context.Context, network, address string) (net.Conn, error)
• type DmDns
  • func NewDmDns(port int) (*DmDns, error)
  • func (s *DmDns) AddRecord(domain string, rtype uint16, rr dns.RR)
  • func (s *DmDns) DNSOverTCP(in io.ReadCloser, out io.Writer) error
  • func (s *DmDns) ForwardRealDNS(req *dns.Msg) (*dns.Msg, error)
  • func (gw *DmDns) HandleUdp(dstAddr net.IP, dstPort uint16, localAddr net.IP, localPort uint16, ...)
  • func (s *DmDns) HostByAddr(addr string) (string, bool)
  • func (s *DmDns) HttpDebugDNS(w http.ResponseWriter, r *http.Request)
  • func (s *DmDns) IPResolve(ip string) string
  • func (s *DmDns) NameByAddr(addr string) (*DnsEntry, bool)
  • func (s *DmDns) Process(req *dns.Msg) *dns.Msg
  • func (s *DmDns) Serve()
  • func (s *DmDns) Start(mux *http.ServeMux)
• type DnsEntry
• type UdpWriter

Functions

func DNSDialer

func DNSDialer(port int) func(ctx context.Context, network, address string) (net.Conn, error)

Types

type DmDns

type DmDns struct {
	UDPConn *net.UDPConn

	// UDP
	// Capture return - sends packets back to client app.
	// This is typically a netstack or TProxy
	UDPWriter UdpWriter

	// Client used for communicating with the gateway - should be capable of H2, and have
	// all authetication set up.
	H2 *http.Client

	// Address and port for the DNS-over-https gateway. If empty, direct calls
	// using dnsUDPClient.
	BaseUrl string

	Port int
	// contains filtered or unexported fields
}

func NewDmDns

func NewDmDns(port int) (*DmDns, error)

New DNS server, listening on port.

func (*DmDns) AddRecord

func (s *DmDns) AddRecord(domain string, rtype uint16, rr dns.RR)

func (*DmDns) DNSOverTCP

func (s *DmDns) DNSOverTCP(in io.ReadCloser, out io.Writer) error

DNSOverTCP implements DNS over TCP protocol. Used in TCP capture, for port 53. TODO: also as a standalone server.

func (*DmDns) ForwardRealDNS

func (s *DmDns) ForwardRealDNS(req *dns.Msg) (*dns.Msg, error)

ForwardRealDNS sends the query to real nameservers.

func (*DmDns) HandleUdp

func (gw *DmDns) HandleUdp(dstAddr net.IP, dstPort uint16, localAddr net.IP, localPort uint16, data []byte)

Special capture for DNS. Will use the DNS VPN or direct calls.

func (*DmDns) HostByAddr

func (s *DmDns) HostByAddr(addr string) (string, bool)

HostByAddr returns the last lookup address for an IP, or the original address. The IP is expressed as a string ( ip.String() ).

func (*DmDns) HttpDebugDNS

func (s *DmDns) HttpDebugDNS(w http.ResponseWriter, r *http.Request)

HttpDebugDNS dumps DNS cache (dnsByName)

func (*DmDns) IPResolve

func (s *DmDns) IPResolve(ip string) string

func (*DmDns) NameByAddr

func (s *DmDns) NameByAddr(addr string) (*DnsEntry, bool)

Given an IPv4 or IPv6 address, return the name if DNS was used.

func (*DmDns) Process

func (s *DmDns) Process(req *dns.Msg) *dns.Msg

Process resolves a query by forwarding to a recursive nameserver or handling it locally. This is the main function - can be called from: - the real local UDP DNS (mike's) - DNS-over-TCP or TLS server - captured UDP:53 from TUN

Wrapps the real process method with stats gathering and builds a reverse map of IP to names

func (*DmDns) Serve

func (s *DmDns) Serve()

Blocking

func (*DmDns) Start

func (s *DmDns) Start(mux *http.ServeMux)

type DnsEntry

type DnsEntry struct {

	// DNS name, with trailing .
	Name string

	IP net.IP

	// Number of times it was called.
	Count int

	RCount int

	// Latency on getting the entry
	Lat time.Duration
	// contains filtered or unexported fields
}

Info and stats about a DNS entry.

type UdpWriter

type UdpWriter interface {
	WriteTo(data []byte, dstAddr *net.UDPAddr, srcAddr *net.UDPAddr) (int, error)
}

UdpWriter is the interface implemented by the TunTransport, to send packets back to the virtual interface Set by TProxy and TUN capture. If missing, a regular UDP will be used, first with WriteMsgUdp and if it fails without preserving srcAddr.