Merge pull request #54219 from m1093782566/ipset

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Using ipset doing SNAT and packet filter in IPVS kube-proxy

**What this PR does / why we need it**:

Try ipset in ipvs proxy mode.

**Which issue this PR fixes**: 

fixes #54203

xref: #53393, #53775

**Special notes for your reviewer**:

**Release note**:

```release-note
Using ipset doing SNAT and packet filtering in IPVS kube-proxy
```

/sig network

/area kube-proxy

pkg/proxy/util/endpoints.go

@@ -19,6 +19,7 @@ package util
 import (
 	"fmt"
 	"net"
+	"strconv"
 
 	"github.com/golang/glog"
 )
@@ -46,6 +47,21 @@ func IPPart(s string) string {
 	return ""
 }
 
+func PortPart(s string) (int, error) {
+	// Must be IP:port
+	_, port, err := net.SplitHostPort(s)
+	if err != nil {
+		glog.Errorf("Error parsing '%s': %v", s, err)
+		return -1, err
+	}
+	portNumber, err := strconv.Atoi(port)
+	if err != nil {
+		glog.Errorf("Error parsing '%s': %v", port, err)
+		return -1, err
+	}
+	return portNumber, nil
+}
+
 // ToCIDR returns a host address of the form <ip-address>/32 for
 // IPv4 and <ip-address>/128 for IPv6
 func ToCIDR(ip net.IP) string {