send Version Negotiation packets in a separate Go routine

conn_test.go

@@ -1,7 +1,6 @@
 package quic
 
 import (
-	"bytes"
 	"errors"
 	"net"
 	"time"
@@ -10,19 +9,24 @@ import (
 	. "github.com/onsi/gomega"
 )
 
+type mockPacketConnWrite struct {
+	data []byte
+	to   net.Addr
+}
+
 type mockPacketConn struct {
-	addr          net.Addr
-	dataToRead    chan []byte
-	dataReadFrom  net.Addr
-	readErr       error
-	dataWritten   bytes.Buffer
-	dataWrittenTo net.Addr
-	closed        bool
+	addr         net.Addr
+	dataToRead   chan []byte
+	dataReadFrom net.Addr
+	readErr      error
+	dataWritten  chan mockPacketConnWrite
+	closed       bool
 }
 
 func newMockPacketConn() *mockPacketConn {
 	return &mockPacketConn{
-		dataToRead: make(chan []byte, 1000),
+		dataToRead:  make(chan []byte, 1000),
+		dataWritten: make(chan mockPacketConnWrite, 1000),
 	}
 }
 
@@ -37,10 +41,16 @@ func (c *mockPacketConn) ReadFrom(b []byte) (int, net.Addr, error) {
 	n := copy(b, data)
 	return n, c.dataReadFrom, nil
 }
+
 func (c *mockPacketConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
-	c.dataWrittenTo = addr
-	return c.dataWritten.Write(b)
+	select {
+	case c.dataWritten <- mockPacketConnWrite{to: addr, data: b}:
+		return len(b), nil
+	default:
+		panic("channel full")
+	}
 }
+
 func (c *mockPacketConn) Close() error {
 	if !c.closed {
 		close(c.dataToRead)
@@ -72,10 +82,11 @@ var _ = Describe("Connection", func() {
 	})
 
 	It("writes", func() {
-		err := c.Write([]byte("foobar"))
-		Expect(err).ToNot(HaveOccurred())
-		Expect(packetConn.dataWritten.Bytes()).To(Equal([]byte("foobar")))
-		Expect(packetConn.dataWrittenTo.String()).To(Equal("192.168.100.200:1337"))
+		Expect(c.Write([]byte("foobar"))).To(Succeed())
+		var write mockPacketConnWrite
+		Expect(packetConn.dataWritten).To(Receive(&write))
+		Expect(write.to.String()).To(Equal("192.168.100.200:1337"))
+		Expect(write.data).To(Equal([]byte("foobar")))
 	})
 
 	It("reads", func() {

server.go

@@ -299,23 +299,17 @@ func (s *server) Addr() net.Addr {
 }
 
 func (s *server) handlePacket(p *receivedPacket) {
-	if err := s.handlePacketImpl(p); err != nil {
-		s.logger.Debugf("error handling packet from %s: %s", p.remoteAddr, err)
-	}
-}
-
-func (s *server) handlePacketImpl(p *receivedPacket) error {
 	hdr := p.hdr
 
 	// send a Version Negotiation Packet if the client is speaking a different protocol version
 	if !protocol.IsSupportedVersion(s.config.Versions, hdr.Version) {
-		return s.sendVersionNegotiationPacket(p)
+		go s.sendVersionNegotiationPacket(p)
+		return
 	}
 	if hdr.Type == protocol.PacketTypeInitial {
 		go s.handleInitial(p)
 	}
 	// TODO(#943): send Stateless Reset
-	return nil
 }
 
 func (s *server) handleInitial(p *receivedPacket) {
@@ -450,14 +444,15 @@ func (s *server) sendRetry(remoteAddr net.Addr, hdr *wire.Header) error {
 	return nil
 }
 
-func (s *server) sendVersionNegotiationPacket(p *receivedPacket) error {
+func (s *server) sendVersionNegotiationPacket(p *receivedPacket) {
 	hdr := p.hdr
-	s.logger.Debugf("Client offered version %s, sending VersionNegotiationPacket", hdr.Version)
-
+	s.logger.Debugf("Client offered version %s, sending Version Negotiation", hdr.Version)
 	data, err := wire.ComposeVersionNegotiation(hdr.SrcConnectionID, hdr.DestConnectionID, s.config.Versions)
 	if err != nil {
-		return err
+		s.logger.Debugf("Error composing Version Negotiation: %s", err)
+		return
+	}
+	if _, err := s.conn.WriteTo(data, p.remoteAddr); err != nil {
+		s.logger.Debugf("Error sending Version Negotiation: %s", err)
 	}
-	_, err = s.conn.WriteTo(data, p.remoteAddr)
-	return err
 }

server_test.go

@@ -113,7 +113,7 @@ var _ = Describe("Server", func() {
 					Version:          serv.config.Versions[0],
 				},
 			})
-			Expect(conn.dataWritten.Len()).To(BeZero())
+			Consistently(conn.dataWritten).ShouldNot(Receive())
 		})
 
 		It("drops too small Initial", func() {
@@ -126,7 +126,7 @@ var _ = Describe("Server", func() {
 				},
 				data: bytes.Repeat([]byte{0}, protocol.MinInitialPacketSize-100),
 			})
-			Consistently(conn.dataWritten.Len).Should(BeZero())
+			Consistently(conn.dataWritten).ShouldNot(Receive())
 		})
 
 		It("drops packets with a too short connection ID", func() {
@@ -140,7 +140,7 @@ var _ = Describe("Server", func() {
 				},
 				data: bytes.Repeat([]byte{0}, protocol.MinInitialPacketSize),
 			})
-			Consistently(conn.dataWritten.Len).Should(BeZero())
+			Consistently(conn.dataWritten).ShouldNot(Receive())
 		})
 
 		It("drops non-Initial packets", func() {
@@ -208,6 +208,7 @@ var _ = Describe("Server", func() {
 			srcConnID := protocol.ConnectionID{1, 2, 3, 4, 5}
 			destConnID := protocol.ConnectionID{1, 2, 3, 4, 5, 6}
 			serv.handlePacket(&receivedPacket{
+				remoteAddr: &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 1337},
 				hdr: &wire.Header{
 					IsLongHeader:     true,
 					Type:             protocol.PacketTypeInitial,
@@ -216,8 +217,10 @@ var _ = Describe("Server", func() {
 					Version:          0x42,
 				},
 			})
-			Expect(conn.dataWritten.Len()).ToNot(BeZero())
-			hdr, err := wire.ParseHeader(bytes.NewReader(conn.dataWritten.Bytes()), 0)
+			var write mockPacketConnWrite
+			Eventually(conn.dataWritten).Should(Receive(&write))
+			Expect(write.to.String()).To(Equal("127.0.0.1:1337"))
+			hdr, err := wire.ParseHeader(bytes.NewReader(write.data), 0)
 			Expect(err).ToNot(HaveOccurred())
 			Expect(hdr.IsVersionNegotiation()).To(BeTrue())
 			Expect(hdr.DestConnectionID).To(Equal(srcConnID))
@@ -234,12 +237,14 @@ var _ = Describe("Server", func() {
 				Version:          protocol.VersionTLS,
 			}
 			serv.handleInitial(&receivedPacket{
-				remoteAddr: &net.UDPAddr{},
+				remoteAddr: &net.UDPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 1337},
 				hdr:        hdr,
 				data:       bytes.Repeat([]byte{0}, protocol.MinInitialPacketSize),
 			})
-			Expect(conn.dataWritten.Len()).ToNot(BeZero())
-			replyHdr := parseHeader(conn.dataWritten.Bytes())
+			var write mockPacketConnWrite
+			Eventually(conn.dataWritten).Should(Receive(&write))
+			Expect(write.to.String()).To(Equal("127.0.0.1:1337"))
+			replyHdr := parseHeader(write.data)
 			Expect(replyHdr.Type).To(Equal(protocol.PacketTypeRetry))
 			Expect(replyHdr.SrcConnectionID).ToNot(Equal(hdr.DestConnectionID))
 			Expect(replyHdr.DestConnectionID).To(Equal(hdr.SrcConnectionID))
@@ -288,7 +293,7 @@ var _ = Describe("Server", func() {
 				defer GinkgoRecover()
 				serv.handlePacket(p)
 				// the Handshake packet is written by the session
-				Expect(conn.dataWritten.Len()).To(BeZero())
+				Consistently(conn.dataWritten).ShouldNot(Receive())
 				close(done)
 			}()
 			// make sure we're using a server-generated connection ID