From aa101d9dc2149781f134f30ed4e636a824b1a60a Mon Sep 17 00:00:00 2001
From: yuhan6665 <1588741+yuhan6665@users.noreply.github.com>
Date: Wed, 28 Feb 2024 21:35:35 -0500
Subject: [PATCH] Doq (#3073)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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* feat: change ALPN of DNS over QUIC

* Fix: length of DNS over QUIC (#1888)

---------

Co-authored-by: 秋のかえで <autmaple@protonmail.com>
---
 app/dns/nameserver_quic.go | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/app/dns/nameserver_quic.go b/app/dns/nameserver_quic.go
index 9e702564..89bb4aaa 100644
--- a/app/dns/nameserver_quic.go
+++ b/app/dns/nameserver_quic.go
@@ -1,7 +1,9 @@
 package dns
 
 import (
+	"bytes"
 	"context"
+	"encoding/binary"
 	"net/url"
 	"sync"
 	"sync/atomic"
@@ -24,7 +26,7 @@ import (
 
 // NextProtoDQ - During connection establishment, DNS/QUIC support is indicated
 // by selecting the ALPN token "dq" in the crypto handshake.
-const NextProtoDQ = "doq-i00"
+const NextProtoDQ = "doq"
 
 const handshakeTimeout = time.Second * 8
 
@@ -194,13 +196,18 @@ func (s *QUICNameServer) sendQuery(ctx context.Context, domain string, clientIP
 				return
 			}
 
+			dnsReqBuf := buf.New()
+			binary.Write(dnsReqBuf, binary.BigEndian, uint16(b.Len()))
+			dnsReqBuf.Write(b.Bytes())
+			b.Release()
+
 			conn, err := s.openStream(dnsCtx)
 			if err != nil {
 				newError("failed to open quic connection").Base(err).AtError().WriteToLog()
 				return
 			}
 
-			_, err = conn.Write(b.Bytes())
+			_, err = conn.Write(dnsReqBuf.Bytes())
 			if err != nil {
 				newError("failed to send query").Base(err).AtError().WriteToLog()
 				return
@@ -210,9 +217,21 @@ func (s *QUICNameServer) sendQuery(ctx context.Context, domain string, clientIP
 
 			respBuf := buf.New()
 			defer respBuf.Release()
-			n, err := respBuf.ReadFrom(conn)
+			n, err := respBuf.ReadFullFrom(conn, 2)
 			if err != nil && n == 0 {
-				newError("failed to read response").Base(err).AtError().WriteToLog()
+				newError("failed to read response length").Base(err).AtError().WriteToLog()
+				return
+			}
+			var length int16
+			err = binary.Read(bytes.NewReader(respBuf.Bytes()), binary.BigEndian, &length)
+			if err != nil {
+				newError("failed to parse response length").Base(err).AtError().WriteToLog()
+				return
+			}
+			respBuf.Clear()
+			n, err = respBuf.ReadFullFrom(conn, int32(length))
+			if err != nil && n == 0 {
+				newError("failed to read response length").Base(err).AtError().WriteToLog()
 				return
 			}