refactor: doq dialer

dns/doq.go

@@ -0,0 +1,197 @@
+package dns
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"fmt"
+	"github.com/Dreamacro/clash/component/dialer"
+	"github.com/Dreamacro/clash/component/resolver"
+	"net"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/Dreamacro/clash/log"
+	"github.com/lucas-clemente/quic-go"
+	D "github.com/miekg/dns"
+)
+
+const NextProtoDQ = "doq-i00"
+
+var bytesPool = sync.Pool{New: func() interface{} { return &bytes.Buffer{} }}
+
+type quicClient struct {
+	addr         string
+	r            *Resolver
+	session      quic.Connection
+	proxyAdapter string
+	sync.RWMutex // protects session and bytesPool
+}
+
+func newDOQ(r *Resolver, addr, proxyAdapter string) *quicClient {
+	return &quicClient{
+		addr:         addr,
+		r:            r,
+		proxyAdapter: proxyAdapter,
+	}
+}
+
+func (dc *quicClient) Exchange(m *D.Msg) (msg *D.Msg, err error) {
+	return dc.ExchangeContext(context.Background(), m)
+}
+
+func (dc *quicClient) ExchangeContext(ctx context.Context, m *D.Msg) (msg *D.Msg, err error) {
+	stream, err := dc.openStream(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open new stream to %s", dc.addr)
+	}
+
+	buf, err := m.Pack()
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = stream.Write(buf)
+	if err != nil {
+		return nil, err
+	}
+
+	// The client MUST send the DNS query over the selected stream, and MUST
+	// indicate through the STREAM FIN mechanism that no further data will
+	// be sent on that stream.
+	// stream.Close() -- closes the write-direction of the stream.
+	_ = stream.Close()
+
+	respBuf := bytesPool.Get().(*bytes.Buffer)
+	defer bytesPool.Put(respBuf)
+	defer respBuf.Reset()
+
+	n, err := respBuf.ReadFrom(stream)
+	if err != nil && n == 0 {
+		return nil, err
+	}
+
+	reply := new(D.Msg)
+	err = reply.Unpack(respBuf.Bytes())
+	if err != nil {
+		return nil, err
+	}
+
+	return reply, nil
+}
+
+func isActive(s quic.Connection) bool {
+	select {
+	case <-s.Context().Done():
+		return false
+	default:
+		return true
+	}
+}
+
+// getSession - opens or returns an existing quic.Connection
+// useCached - if true and cached session exists, return it right away
+// otherwise - forcibly creates a new session
+func (dc *quicClient) getSession() (quic.Connection, error) {
+	var session quic.Connection
+	dc.RLock()
+	session = dc.session
+	if session != nil && isActive(session) {
+		dc.RUnlock()
+		return session, nil
+	}
+	if session != nil {
+		// we're recreating the session, let's create a new one
+		_ = session.CloseWithError(0, "")
+	}
+	dc.RUnlock()
+
+	dc.Lock()
+	defer dc.Unlock()
+
+	var err error
+	session, err = dc.openSession()
+	if err != nil {
+		// This does not look too nice, but QUIC (or maybe quic-go)
+		// doesn't seem stable enough.
+		// Maybe retransmissions aren't fully implemented in quic-go?
+		// Anyways, the simple solution is to make a second try when
+		// it fails to open the QUIC session.
+		session, err = dc.openSession()
+		if err != nil {
+			return nil, err
+		}
+	}
+	dc.session = session
+	return session, nil
+}
+
+func (dc *quicClient) openSession() (quic.Connection, error) {
+	tlsConfig := &tls.Config{
+		InsecureSkipVerify: true,
+		NextProtos: []string{
+			"http/1.1", "h2", NextProtoDQ,
+		},
+		SessionTicketsDisabled: false,
+	}
+	quicConfig := &quic.Config{
+		ConnectionIDLength:   12,
+		HandshakeIdleTimeout: time.Second * 8,
+	}
+
+	log.Debugln("opening session to %s", dc.addr)
+	var (
+		udp net.PacketConn
+		err error
+	)
+
+	host, port, err := net.SplitHostPort(dc.addr)
+	if err != nil {
+		return nil, err
+	}
+
+	ip, err := resolver.ResolveIPv4WithResolver(host, dc.r)
+	if err != nil {
+		return nil, err
+	}
+
+	p, err := strconv.Atoi(port)
+	udpAddr := net.UDPAddr{IP: ip.AsSlice(), Port: p}
+
+	if dc.proxyAdapter == "" {
+		udp, err = dialer.ListenPacket(context.Background(), "udp", "")
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		conn, err := dialContextWithProxyAdapter(context.Background(), dc.proxyAdapter, "udp", ip, port)
+		if err != nil {
+			return nil, err
+		}
+
+		wrapConn, ok := conn.(*wrapPacketConn)
+		if !ok {
+			return nil, fmt.Errorf("quio create packet failed")
+		}
+
+		udp = wrapConn.PacketConn
+	}
+
+	session, err := quic.Dial(udp, &udpAddr, host, tlsConfig, quicConfig)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open QUIC session: %w", err)
+	}
+
+	return session, nil
+}
+
+func (dc *quicClient) openStream(ctx context.Context) (quic.Stream, error) {
+	session, err := dc.getSession()
+	if err != nil {
+		return nil, err
+	}
+
+	// open a new stream
+	return session.OpenStreamSync(ctx)
+}