Import code, preparing for release

doq.go

@@ -0,0 +1,75 @@
+package ctrld
+
+import (
+	"context"
+	"crypto/tls"
+	"io"
+	"net"
+	"time"
+
+	"github.com/lucas-clemente/quic-go"
+	"github.com/miekg/dns"
+)
+
+type doqResolver struct {
+	uc *UpstreamConfig
+}
+
+func (r *doqResolver) Resolve(ctx context.Context, msg *dns.Msg) (*dns.Msg, error) {
+	endpoint := r.uc.Endpoint
+	tlsConfig := &tls.Config{NextProtos: []string{"doq"}}
+	if r.uc.BootstrapIP != "" {
+		tlsConfig.ServerName = r.uc.Domain
+		_, port, _ := net.SplitHostPort(endpoint)
+		endpoint = net.JoinHostPort(r.uc.BootstrapIP, port)
+	}
+	return resolve(ctx, msg, endpoint, tlsConfig)
+}
+
+func resolve(ctx context.Context, msg *dns.Msg, endpoint string, tlsConfig *tls.Config) (*dns.Msg, error) {
+	session, err := quic.DialAddr(endpoint, tlsConfig, nil)
+	if err != nil {
+		return nil, err
+	}
+	defer session.CloseWithError(quic.ApplicationErrorCode(quic.NoError), "")
+
+	msgBytes, err := msg.Pack()
+	if err != nil {
+		return nil, err
+	}
+
+	stream, err := session.OpenStream()
+	if err != nil {
+		return nil, err
+	}
+
+	deadline, ok := ctx.Deadline()
+	if !ok {
+		deadline = time.Now().Add(5 * time.Second)
+	}
+	_ = stream.SetDeadline(deadline)
+
+	var msgLen = uint16(len(msgBytes))
+	var msgLenBytes = []byte{byte(msgLen >> 8), byte(msgLen & 0xFF)}
+	if _, err := stream.Write(msgLenBytes); err != nil {
+		return nil, err
+	}
+
+	if _, err := stream.Write(msgBytes); err != nil {
+		return nil, err
+	}
+
+	buf, err := io.ReadAll(stream)
+	if err != nil {
+		return nil, err
+	}
+
+	_ = stream.Close()
+
+	answer := new(dns.Msg)
+	if err := answer.Unpack(buf[2:]); err != nil {
+		return nil, err
+	}
+	answer.SetReply(msg)
+	return answer, nil
+}