perform send / receive buffer increases when setting up the connection (#3949)

The UDP send and receive buffer is now increased when calling
OptimizeConn.

sys_conn.go

@@ -2,7 +2,11 @@ package quic
 
 import (
 	"fmt"
+	"log"
 	"net"
+	"os"
+	"strconv"
+	"strings"
 	"syscall"
 	"time"
 
@@ -44,6 +48,27 @@ func wrapConn(pc net.PacketConn) (interface {
 	rawConn
 }, error,
 ) {
+	if err := setReceiveBuffer(pc); err != nil {
+		if !strings.Contains(err.Error(), "use of closed network connection") {
+			setBufferWarningOnce.Do(func() {
+				if disable, _ := strconv.ParseBool(os.Getenv("QUIC_GO_DISABLE_RECEIVE_BUFFER_WARNING")); disable {
+					return
+				}
+				log.Printf("%s. See https://github.com/quic-go/quic-go/wiki/UDP-Buffer-Sizes for details.", err)
+			})
+		}
+	}
+	if err := setSendBuffer(pc); err != nil {
+		if !strings.Contains(err.Error(), "use of closed network connection") {
+			setBufferWarningOnce.Do(func() {
+				if disable, _ := strconv.ParseBool(os.Getenv("QUIC_GO_DISABLE_RECEIVE_BUFFER_WARNING")); disable {
+					return
+				}
+				log.Printf("%s. See https://github.com/quic-go/quic-go/wiki/UDP-Buffer-Sizes for details.", err)
+			})
+		}
+	}
+
 	conn, ok := pc.(interface {
 		SyscallConn() (syscall.RawConn, error)
 	})

sys_conn_buffers.go

@@ -11,7 +11,7 @@ import (
 )
 
 //go:generate sh -c "echo '// Code generated by go generate. DO NOT EDIT.\n// Source: sys_conn_buffers.go\n' > sys_conn_buffers_write.go && sed -e 's/SetReadBuffer/SetWriteBuffer/g' -e 's/setReceiveBuffer/setSendBuffer/g' -e 's/inspectReadBuffer/inspectWriteBuffer/g' -e 's/protocol\\.DesiredReceiveBufferSize/protocol\\.DesiredSendBufferSize/g' -e 's/forceSetReceiveBuffer/forceSetSendBuffer/g' -e 's/receive buffer/send buffer/g' sys_conn_buffers.go | sed '/^\\/\\/go:generate/d' >> sys_conn_buffers_write.go"
-func setReceiveBuffer(c net.PacketConn, logger utils.Logger) error {
+func setReceiveBuffer(c net.PacketConn) error {
 	conn, ok := c.(interface{ SetReadBuffer(int) error })
 	if !ok {
 		return errors.New("connection doesn't allow setting of receive buffer size. Not a *net.UDPConn?")
@@ -40,7 +40,7 @@ func setReceiveBuffer(c net.PacketConn, logger utils.Logger) error {
 		return fmt.Errorf("failed to determine receive buffer size: %w", err)
 	}
 	if size >= protocol.DesiredReceiveBufferSize {
-		logger.Debugf("Conn has receive buffer of %d kiB (wanted: at least %d kiB)", size/1024, protocol.DesiredReceiveBufferSize/1024)
+		utils.DefaultLogger.Debugf("Conn has receive buffer of %d kiB (wanted: at least %d kiB)", size/1024, protocol.DesiredReceiveBufferSize/1024)
 		return nil
 	}
 	// Ignore the error. We check if we succeeded by querying the buffer size afterward.
@@ -63,6 +63,6 @@ func setReceiveBuffer(c net.PacketConn, logger utils.Logger) error {
 	if newSize < protocol.DesiredReceiveBufferSize {
 		return fmt.Errorf("failed to sufficiently increase receive buffer size (was: %d kiB, wanted: %d kiB, got: %d kiB)", size/1024, protocol.DesiredReceiveBufferSize/1024, newSize/1024)
 	}
-	logger.Debugf("Increased receive buffer size to %d kiB", newSize/1024)
+	utils.DefaultLogger.Debugf("Increased receive buffer size to %d kiB", newSize/1024)
 	return nil
 }

sys_conn_buffers_write.go

@@ -13,7 +13,7 @@ import (
 	"github.com/quic-go/quic-go/internal/utils"
 )
 
-func setSendBuffer(c net.PacketConn, logger utils.Logger) error {
+func setSendBuffer(c net.PacketConn) error {
 	conn, ok := c.(interface{ SetWriteBuffer(int) error })
 	if !ok {
 		return errors.New("connection doesn't allow setting of send buffer size. Not a *net.UDPConn?")
@@ -42,7 +42,7 @@ func setSendBuffer(c net.PacketConn, logger utils.Logger) error {
 		return fmt.Errorf("failed to determine send buffer size: %w", err)
 	}
 	if size >= protocol.DesiredSendBufferSize {
-		logger.Debugf("Conn has send buffer of %d kiB (wanted: at least %d kiB)", size/1024, protocol.DesiredSendBufferSize/1024)
+		utils.DefaultLogger.Debugf("Conn has send buffer of %d kiB (wanted: at least %d kiB)", size/1024, protocol.DesiredSendBufferSize/1024)
 		return nil
 	}
 	// Ignore the error. We check if we succeeded by querying the buffer size afterward.
@@ -65,6 +65,6 @@ func setSendBuffer(c net.PacketConn, logger utils.Logger) error {
 	if newSize < protocol.DesiredSendBufferSize {
 		return fmt.Errorf("failed to sufficiently increase send buffer size (was: %d kiB, wanted: %d kiB, got: %d kiB)", size/1024, protocol.DesiredSendBufferSize/1024, newSize/1024)
 	}
-	logger.Debugf("Increased send buffer size to %d kiB", newSize/1024)
+	utils.DefaultLogger.Debugf("Increased send buffer size to %d kiB", newSize/1024)
 	return nil
 }

transport.go

@@ -5,11 +5,7 @@ import (
 	"crypto/rand"
 	"crypto/tls"
 	"errors"
-	"log"
 	"net"
-	"os"
-	"strconv"
-	"strings"
 	"sync"
 	"time"
 
@@ -302,27 +298,6 @@ func (t *Transport) listen(conn rawConn) {
 	defer close(t.listening)
 	defer getMultiplexer().RemoveConn(t.Conn)
 
-	if err := setReceiveBuffer(t.Conn, t.logger); err != nil {
-		if !strings.Contains(err.Error(), "use of closed network connection") {
-			setBufferWarningOnce.Do(func() {
-				if disable, _ := strconv.ParseBool(os.Getenv("QUIC_GO_DISABLE_RECEIVE_BUFFER_WARNING")); disable {
-					return
-				}
-				log.Printf("%s. See https://github.com/quic-go/quic-go/wiki/UDP-Buffer-Sizes for details.", err)
-			})
-		}
-	}
-	if err := setSendBuffer(t.Conn, t.logger); err != nil {
-		if !strings.Contains(err.Error(), "use of closed network connection") {
-			setBufferWarningOnce.Do(func() {
-				if disable, _ := strconv.ParseBool(os.Getenv("QUIC_GO_DISABLE_RECEIVE_BUFFER_WARNING")); disable {
-					return
-				}
-				log.Printf("%s. See https://github.com/quic-go/quic-go/wiki/UDP-Buffer-Sizes for details.", err)
-			})
-		}
-	}
-
 	for {
 		p, err := conn.ReadPacket()
 		//nolint:staticcheck // SA1019 ignore this!