use tighter retry that cancels and backs off

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

internal/outpost/radius/eap/tls/buff_conn.go

@@ -3,9 +3,11 @@ package tls
 import (
 	"bytes"
 	"context"
+	"errors"
 	"net"
 	"time"
 
+	"github.com/avast/retry-go/v4"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -17,6 +19,8 @@ type BuffConn struct {
 
 	expectedWriterByteCount int
 	writtenByteCount        int
+
+	retryOptions []retry.Option
 }
 
 func NewBuffConn(initialData []byte, ctx context.Context) *BuffConn {
@@ -24,21 +28,34 @@ func NewBuffConn(initialData []byte, ctx context.Context) *BuffConn {
 		reader: bytes.NewBuffer(initialData),
 		writer: bytes.NewBuffer([]byte{}),
 		ctx:    ctx,
+		retryOptions: []retry.Option{
+			retry.Context(ctx),
+			retry.Delay(10 * time.Microsecond),
+			retry.DelayType(retry.BackOffDelay),
+			retry.MaxDelay(100 * time.Millisecond),
+			retry.Attempts(0),
+		},
 	}
 	return c
 }
 
+var errStall = errors.New("Stall")
+
 func (conn BuffConn) OutboundData() []byte {
-	for {
-		// TODO cancel with conn.ctx
-		b := conn.writer.Bytes()
-		if len(b) < 1 {
-			log.Debug("TLS(buffcon): Attempted retrieve from empty buffer, stalling...")
-			time.Sleep(1 * time.Second)
-			continue
-		}
-		return b
+	d, err := retry.DoWithData(
+		func() ([]byte, error) {
+			b := conn.writer.Bytes()
+			if len(b) < 1 {
+				return nil, errStall
+			}
+			return b, nil
+		},
+		conn.retryOptions...,
+	)
+	if err != nil {
+		return []byte{}
 	}
+	return d
 }
 
 func (conn *BuffConn) UpdateData(data []byte) {
@@ -55,28 +72,29 @@ func (conn BuffConn) NeedsMoreData() bool {
 }
 
 func (conn *BuffConn) Read(p []byte) (int, error) {
-	for {
-		// TODO cancel with conn.ctx
-		n, err := conn.reader.Read(p)
-		if n == 0 {
-			log.Debugf("TLS(buffcon): Attempted read %d from empty buffer, stalling...", len(p))
-			time.Sleep(100 * time.Millisecond)
-			continue
-		}
-		if conn.expectedWriterByteCount > 0 && conn.writtenByteCount < int(conn.expectedWriterByteCount) {
-			log.Debugf("TLS(buffcon): Attempted read %d while waiting for bytes %d, stalling...", len(p), conn.expectedWriterByteCount-conn.reader.Len())
-			time.Sleep(100 * time.Millisecond)
-			continue
-		}
-		if conn.expectedWriterByteCount > 0 && conn.writtenByteCount == int(conn.expectedWriterByteCount) {
-			conn.expectedWriterByteCount = 0
-		}
-		if conn.reader.Len() == 0 {
-			conn.writtenByteCount = 0
-		}
-		log.Debugf("TLS(buffcon): Read: %d from %d", len(p), n)
-		return n, err
-	}
+	d, err := retry.DoWithData(
+		func() (int, error) {
+			n, err := conn.reader.Read(p)
+			if n == 0 {
+				log.Debugf("TLS(buffcon): Attempted read %d from empty buffer, stalling...", len(p))
+				return 0, errStall
+			}
+			if conn.expectedWriterByteCount > 0 && conn.writtenByteCount < int(conn.expectedWriterByteCount) {
+				log.Debugf("TLS(buffcon): Attempted read %d while waiting for bytes %d, stalling...", len(p), conn.expectedWriterByteCount-conn.reader.Len())
+				return 0, errStall
+			}
+			if conn.expectedWriterByteCount > 0 && conn.writtenByteCount == int(conn.expectedWriterByteCount) {
+				conn.expectedWriterByteCount = 0
+			}
+			if conn.reader.Len() == 0 {
+				conn.writtenByteCount = 0
+			}
+			log.Debugf("TLS(buffcon): Read: %d from %d", len(p), n)
+			return n, err
+		},
+		conn.retryOptions...,
+	)
+	return d, err
 }
 
 func (conn BuffConn) Write(p []byte) (int, error) {