initial commit
This commit is contained in:
ginuerzh
210
listener/dns/listener.go
Normal file
210
listener/dns/listener.go
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@ -0,0 +1,210 @@
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package dns
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import (
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"bytes"
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"encoding/base64"
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"errors"
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"io/ioutil"
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"net"
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"net/http"
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"strings"
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"github.com/go-gost/gost/v3/pkg/common/metrics"
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"github.com/go-gost/gost/v3/pkg/listener"
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"github.com/go-gost/gost/v3/pkg/logger"
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md "github.com/go-gost/gost/v3/pkg/metadata"
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"github.com/go-gost/gost/v3/pkg/registry"
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"github.com/miekg/dns"
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)
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func init() {
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registry.ListenerRegistry().Register("dns", NewListener)
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}
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type dnsListener struct {
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addr net.Addr
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server Server
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cqueue chan net.Conn
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errChan chan error
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logger logger.Logger
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md metadata
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options listener.Options
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}
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func NewListener(opts ...listener.Option) listener.Listener {
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options := listener.Options{}
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for _, opt := range opts {
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opt(&options)
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}
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return &dnsListener{
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logger: options.Logger,
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options: options,
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}
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}
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func (l *dnsListener) Init(md md.Metadata) (err error) {
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if err = l.parseMetadata(md); err != nil {
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return
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}
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l.addr, err = net.ResolveTCPAddr("tcp", l.options.Addr)
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if err != nil {
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return err
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}
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switch strings.ToLower(l.md.mode) {
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case "tcp":
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l.server = &dns.Server{
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Net: "tcp",
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Addr: l.options.Addr,
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Handler: l,
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ReadTimeout: l.md.readTimeout,
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WriteTimeout: l.md.writeTimeout,
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}
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case "tls":
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l.server = &dns.Server{
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Net: "tcp-tls",
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Addr: l.options.Addr,
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Handler: l,
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TLSConfig: l.options.TLSConfig,
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ReadTimeout: l.md.readTimeout,
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WriteTimeout: l.md.writeTimeout,
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}
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case "https":
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l.server = &dohServer{
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addr: l.options.Addr,
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tlsConfig: l.options.TLSConfig,
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server: &http.Server{
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Handler: l,
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ReadTimeout: l.md.readTimeout,
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WriteTimeout: l.md.writeTimeout,
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},
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}
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default:
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l.addr, err = net.ResolveUDPAddr("udp", l.options.Addr)
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l.server = &dns.Server{
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Net: "udp",
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Addr: l.options.Addr,
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Handler: l,
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UDPSize: l.md.readBufferSize,
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ReadTimeout: l.md.readTimeout,
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WriteTimeout: l.md.writeTimeout,
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}
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}
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if err != nil {
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return
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}
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l.cqueue = make(chan net.Conn, l.md.backlog)
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l.errChan = make(chan error, 1)
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go func() {
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err := l.server.ListenAndServe()
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if err != nil {
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l.errChan <- err
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}
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close(l.errChan)
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}()
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return
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}
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func (l *dnsListener) Accept() (conn net.Conn, err error) {
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var ok bool
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select {
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case conn = <-l.cqueue:
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conn = metrics.WrapConn(l.options.Service, conn)
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case err, ok = <-l.errChan:
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if !ok {
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err = listener.ErrClosed
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}
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}
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return
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}
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func (l *dnsListener) Close() error {
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return l.server.Shutdown()
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}
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func (l *dnsListener) Addr() net.Addr {
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return l.addr
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}
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func (l *dnsListener) ServeDNS(w dns.ResponseWriter, m *dns.Msg) {
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b, err := m.Pack()
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if err != nil {
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l.logger.Error(err)
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return
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}
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if err := l.serve(w, b); err != nil {
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l.logger.Error(err)
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}
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}
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// Based on https://github.com/semihalev/sdns
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func (l *dnsListener) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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var buf []byte
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var err error
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switch r.Method {
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case http.MethodGet:
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buf, err = base64.RawURLEncoding.DecodeString(r.URL.Query().Get("dns"))
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if len(buf) == 0 || err != nil {
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http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
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return
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}
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case http.MethodPost:
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if ct := r.Header.Get("Content-Type"); ct != "application/dns-message" {
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l.logger.Errorf("unsupported media type: %s", ct)
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http.Error(w, http.StatusText(http.StatusUnsupportedMediaType), http.StatusUnsupportedMediaType)
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return
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}
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buf, err = ioutil.ReadAll(r.Body)
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if err != nil {
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l.logger.Error(err)
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http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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return
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}
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default:
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l.logger.Errorf("method not allowd: %s", r.Method)
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http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
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return
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}
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mq := &dns.Msg{}
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if err := mq.Unpack(buf); err != nil {
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l.logger.Error(err)
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http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
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return
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}
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w.Header().Set("Server", "SDNS")
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w.Header().Set("Content-Type", "application/dns-message")
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raddr, _ := net.ResolveTCPAddr("tcp", r.RemoteAddr)
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if raddr == nil {
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raddr = &net.TCPAddr{}
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}
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if err := l.serve(&dohResponseWriter{raddr: raddr, ResponseWriter: w}, buf); err != nil {
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l.logger.Error(err)
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http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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}
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}
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func (l *dnsListener) serve(w ResponseWriter, msg []byte) (err error) {
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conn := &serverConn{
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r: bytes.NewReader(msg),
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w: w,
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laddr: l.addr,
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closed: make(chan struct{}),
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}
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select {
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case l.cqueue <- conn:
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default:
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l.logger.Warnf("connection queue is full, client %s discarded", w.RemoteAddr())
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return errors.New("connection queue is full")
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}
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return conn.Wait()
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}
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41
listener/dns/metadata.go
Normal file
41
listener/dns/metadata.go
Normal file
@ -0,0 +1,41 @@
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package dns
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import (
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"time"
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mdata "github.com/go-gost/gost/v3/pkg/metadata"
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)
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const (
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defaultBacklog = 128
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)
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type metadata struct {
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mode string
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readBufferSize int
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readTimeout time.Duration
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writeTimeout time.Duration
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backlog int
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}
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func (l *dnsListener) parseMetadata(md mdata.Metadata) (err error) {
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const (
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backlog = "backlog"
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mode = "mode"
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readBufferSize = "readBufferSize"
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readTimeout = "readTimeout"
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writeTimeout = "writeTimeout"
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)
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l.md.mode = mdata.GetString(md, mode)
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l.md.readBufferSize = mdata.GetInt(md, readBufferSize)
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l.md.readTimeout = mdata.GetDuration(md, readTimeout)
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l.md.writeTimeout = mdata.GetDuration(md, writeTimeout)
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l.md.backlog = mdata.GetInt(md, backlog)
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if l.md.backlog <= 0 {
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l.md.backlog = defaultBacklog
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}
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return
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}
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110
listener/dns/server.go
Normal file
110
listener/dns/server.go
Normal file
@ -0,0 +1,110 @@
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package dns
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import (
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"context"
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"crypto/tls"
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"errors"
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"io"
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"net"
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"net/http"
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"time"
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)
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type Server interface {
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ListenAndServe() error
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Shutdown() error
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}
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type dohServer struct {
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addr string
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tlsConfig *tls.Config
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server *http.Server
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}
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func (s *dohServer) ListenAndServe() error {
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ln, err := net.Listen("tcp", s.addr)
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if err != nil {
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return err
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}
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ln = tls.NewListener(ln, s.tlsConfig)
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return s.server.Serve(ln)
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}
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func (s *dohServer) Shutdown() error {
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return s.server.Shutdown(context.Background())
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}
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type ResponseWriter interface {
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io.Writer
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RemoteAddr() net.Addr
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}
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type dohResponseWriter struct {
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raddr net.Addr
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http.ResponseWriter
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}
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func (w *dohResponseWriter) RemoteAddr() net.Addr {
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return w.raddr
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}
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type serverConn struct {
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r io.Reader
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w ResponseWriter
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laddr net.Addr
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closed chan struct{}
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}
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func (c *serverConn) Read(b []byte) (n int, err error) {
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select {
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case <-c.closed:
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err = io.ErrClosedPipe
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return
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default:
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return c.r.Read(b)
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}
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}
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func (c *serverConn) Write(b []byte) (n int, err error) {
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select {
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case <-c.closed:
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err = io.ErrClosedPipe
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return
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default:
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return c.w.Write(b)
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}
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}
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func (c *serverConn) Close() error {
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select {
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case <-c.closed:
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default:
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close(c.closed)
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}
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return nil
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}
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func (c *serverConn) Wait() error {
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<-c.closed
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return nil
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}
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func (c *serverConn) LocalAddr() net.Addr {
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return c.laddr
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}
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func (c *serverConn) RemoteAddr() net.Addr {
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return c.w.RemoteAddr()
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}
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func (c *serverConn) SetDeadline(t time.Time) error {
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return &net.OpError{Op: "set", Net: "dns", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
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}
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func (c *serverConn) SetReadDeadline(t time.Time) error {
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return &net.OpError{Op: "set", Net: "dns", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
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}
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func (c *serverConn) SetWriteDeadline(t time.Time) error {
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return &net.OpError{Op: "set", Net: "dns", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
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}
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