conncheck for badconn (#1821)

internal/pool/conncheck.go

@@ -0,0 +1,45 @@
+// +build linux darwin dragonfly freebsd netbsd openbsd solaris illumos
+
+package pool
+
+import (
+	"errors"
+	"io"
+	"net"
+	"syscall"
+)
+
+var errUnexpectedRead = errors.New("unexpected read from socket")
+
+func connCheck(conn net.Conn) error {
+	sysConn, ok := conn.(syscall.Conn)
+	if !ok {
+		return nil
+	}
+	rawConn, err := sysConn.SyscallConn()
+	if err != nil {
+		return err
+	}
+
+	var sysErr error
+	err = rawConn.Read(func(fd uintptr) bool {
+		var buf [1]byte
+		n, err := syscall.Read(int(fd), buf[:])
+		switch {
+		case n == 0 && err == nil:
+			sysErr = io.EOF
+		case n > 0:
+			sysErr = errUnexpectedRead
+		case err == syscall.EAGAIN || err == syscall.EWOULDBLOCK:
+			sysErr = nil
+		default:
+			sysErr = err
+		}
+		return true
+	})
+	if err != nil {
+		return err
+	}
+
+	return sysErr
+}

internal/pool/conncheck_dummy.go

@@ -0,0 +1,9 @@
+// +build !linux,!darwin,!dragonfly,!freebsd,!netbsd,!openbsd,!solaris,!illumos
+
+package pool
+
+import "net"
+
+func connCheck(conn net.Conn) error {
+	return nil
+}

internal/pool/conncheck_test.go

@@ -0,0 +1,46 @@
+// +build linux darwin dragonfly freebsd netbsd openbsd solaris illumos
+
+package pool
+
+import (
+	"net"
+	"net/http/httptest"
+	"testing"
+	"time"
+)
+
+func Test_connCheck(t *testing.T) {
+	// tests with real conns
+	ts := httptest.NewServer(nil)
+	defer ts.Close()
+
+	t.Run("good conn", func(t *testing.T) {
+		conn, err := net.DialTimeout(ts.Listener.Addr().Network(), ts.Listener.Addr().String(), time.Second)
+		if err != nil {
+			t.Fatalf(err.Error())
+		}
+		defer conn.Close()
+		if err = connCheck(conn); err != nil {
+			t.Fatalf(err.Error())
+		}
+		conn.Close()
+
+		if err = connCheck(conn); err == nil {
+			t.Fatalf("expect has error")
+		}
+	})
+
+	t.Run("bad conn 2", func(t *testing.T) {
+		conn, err := net.DialTimeout(ts.Listener.Addr().Network(), ts.Listener.Addr().String(), time.Second)
+		if err != nil {
+			t.Fatalf(err.Error())
+		}
+		defer conn.Close()
+
+		ts.Close()
+
+		if err = connCheck(conn); err == nil {
+			t.Fatalf("expect has err")
+		}
+	})
+}

internal/pool/main_test.go

@@ -2,12 +2,14 @@ package pool_test
 
 import (
 	"context"
-	"net"
+	"fmt"
-	"sync"
-	"testing"
-
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"net"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
 )
 
 func TestGinkgoSuite(t *testing.T) {
@@ -32,5 +34,87 @@ func perform(n int, cbs ...func(int)) {
 }
 
 func dummyDialer(context.Context) (net.Conn, error) {
-	return &net.TCPConn{}, nil
+	// return &net.TCPConn{}, nil
+	return newDummyConn(), nil
+}
+
+func newDummyConn() net.Conn {
+	return &dummyConn{
+		rawConn: &dummyRawConn{},
+	}
+}
+
+var _ net.Conn = (*dummyConn)(nil)
+var _ syscall.Conn = (*dummyConn)(nil)
+
+type dummyConn struct {
+	rawConn *dummyRawConn
+}
+
+func (d *dummyConn) SyscallConn() (syscall.RawConn, error) {
+	return d.rawConn, nil
+}
+
+var errDummy = fmt.Errorf("dummyConn err")
+
+func (d *dummyConn) Read(b []byte) (n int, err error) {
+	return 0, errDummy
+}
+
+func (d *dummyConn) Write(b []byte) (n int, err error) {
+	return 0, errDummy
+}
+
+func (d *dummyConn) Close() error {
+	d.rawConn.Close()
+	return nil
+}
+
+func (d *dummyConn) LocalAddr() net.Addr {
+	return &net.TCPAddr{}
+}
+
+func (d *dummyConn) RemoteAddr() net.Addr {
+	return &net.TCPAddr{}
+}
+
+func (d *dummyConn) SetDeadline(t time.Time) error {
+	return nil
+}
+
+func (d *dummyConn) SetReadDeadline(t time.Time) error {
+	return nil
+}
+
+func (d *dummyConn) SetWriteDeadline(t time.Time) error {
+	return nil
+}
+
+var _ syscall.RawConn = (*dummyRawConn)(nil)
+
+type dummyRawConn struct {
+	closed bool
+	mux    sync.Mutex
+}
+
+func (d *dummyRawConn) Control(f func(fd uintptr)) error {
+	return nil
+}
+
+func (d *dummyRawConn) Read(f func(fd uintptr) (done bool)) error {
+	d.mux.Lock()
+	defer d.mux.Unlock()
+	if d.closed {
+		return fmt.Errorf("dummyRawConn closed")
+	}
+	return nil
+}
+
+func (d *dummyRawConn) Write(f func(fd uintptr) (done bool)) error {
+	return nil
+}
+func (d *dummyRawConn) Close() {
+	d.mux.Lock()
+	d.closed = true
+	d.mux.Unlock()
 }

internal/pool/pool.go

@@ -511,7 +511,7 @@ func (p *ConnPool) reapStaleConn() *Conn {
 
 func (p *ConnPool) isStaleConn(cn *Conn) bool {
 	if p.opt.IdleTimeout == 0 && p.opt.MaxConnAge == 0 {
-		return false
+		return connCheck(cn.netConn) != nil
 	}
 
 	now := time.Now()
@@ -522,5 +522,5 @@ func (p *ConnPool) isStaleConn(cn *Conn) bool {
 		return true
 	}
 
-	return false
+	return connCheck(cn.netConn) != nil
 }

internal/pool/pool_test.go

@@ -2,14 +2,13 @@ package pool_test
 
 import (
 	"context"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
 	"sync"
 	"testing"
 	"time"
 
 	"github.com/go-redis/redis/v8/internal/pool"
-
-	. "github.com/onsi/ginkgo"
-	. "github.com/onsi/gomega"
 )
 
 var _ = Describe("ConnPool", func() {
@@ -285,6 +284,8 @@ var _ = Describe("conns reaper", func() {
 					cn.SetUsedAt(time.Now().Add(-2 * idleTimeout))
 				case "aged":
 					cn.SetCreatedAt(time.Now().Add(-2 * maxAge))
+				case "conncheck":
+					cn.Close()
 				}
 				conns = append(conns, cn)
 				staleConns = append(staleConns, cn)
@@ -371,6 +372,7 @@ var _ = Describe("conns reaper", func() {
 
 	assert("idle")
 	assert("aged")
+	assert("conncheck")
 })
 
 var _ = Describe("race", func() {