Backport #3138 to v9.6 (#3145)

Author: rentziass

internal/pool/conn.go

@@ -3,7 +3,6 @@ package pool
 import (
 	"bufio"
 	"context"
-	"crypto/tls"
 	"net"
 	"sync/atomic"
 	"syscall"
@@ -65,9 +64,6 @@ func (cn *Conn) setSysConn() {
 	if conn == nil {
 		return
 	}
-	if tlsConn, ok := conn.(*tls.Conn); ok {
-		conn = tlsConn.NetConn()
-	}
 
 	if sysConn, ok := conn.(syscall.Conn); ok {
 		cn.sysConn = sysConn

internal/pool/conn_check_test.go

@@ -3,7 +3,6 @@
 package pool
 
 import (
-	"crypto/tls"
 	"net"
 	"net/http/httptest"
 	"syscall"
@@ -16,21 +15,14 @@ import (
 var _ = Describe("tests conn_check with real conns", func() {
 	var ts *httptest.Server
 	var conn net.Conn
-	var tlsConn *tls.Conn
 	var sysConn syscall.Conn
-	var tlsSysConn syscall.Conn
 	var err error
 
 	BeforeEach(func() {
 		ts = httptest.NewServer(nil)
 		conn, err = net.DialTimeout(ts.Listener.Addr().Network(), ts.Listener.Addr().String(), time.Second)
 		Expect(err).NotTo(HaveOccurred())
 		sysConn = conn.(syscall.Conn)
-		tlsTestServer := httptest.NewUnstartedServer(nil)
-		tlsTestServer.StartTLS()
-		tlsConn, err = tls.DialWithDialer(&net.Dialer{Timeout: time.Second}, tlsTestServer.Listener.Addr().Network(), tlsTestServer.Listener.Addr().String(), &tls.Config{InsecureSkipVerify: true})
-		Expect(err).NotTo(HaveOccurred())
-		tlsSysConn = tlsConn.NetConn().(syscall.Conn)
 	})
 
 	AfterEach(func() {
@@ -44,23 +36,11 @@ var _ = Describe("tests conn_check with real conns", func() {
 		Expect(connCheck(sysConn)).To(HaveOccurred())
 	})
 
-	It("good tls conn check", func() {
-		Expect(connCheck(tlsSysConn)).NotTo(HaveOccurred())
-
-		Expect(tlsConn.Close()).NotTo(HaveOccurred())
-		Expect(connCheck(tlsSysConn)).To(HaveOccurred())
-	})
-
 	It("bad conn check", func() {
 		Expect(conn.Close()).NotTo(HaveOccurred())
 		Expect(connCheck(sysConn)).To(HaveOccurred())
 	})
 
-	It("bad tls conn check", func() {
-		Expect(tlsConn.Close()).NotTo(HaveOccurred())
-		Expect(connCheck(tlsSysConn)).To(HaveOccurred())
-	})
-
 	It("check conn deadline", func() {
 		Expect(conn.SetDeadline(time.Now())).NotTo(HaveOccurred())
 		time.Sleep(time.Millisecond * 10)