Merge pull request #52015 from m1093782566/flush-ipvs

Automatic merge from submit-queue (batch tested with PRs 51929, 52015, 51906, 52069, 51542). 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>..

Support IPVS Flush API

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

Currently, we implement IPVS flush API by deleting IPVS services one by one, which is inefficient.

**Which issue this PR fixes**: 

fixes #52070

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

vendor/github.com/docker/libnetwork/ipvs/ipvs.go

@@ -116,6 +116,13 @@ func (i *Handle) DelService(s *Service) error {
 	return i.doCmd(s, nil, ipvsCmdDelService)
 }
 
+// Flush deletes all existing services in the passed
+// handle.
+func (i *Handle) Flush() error {
+	_, err := i.doCmdWithoutAttr(ipvsCmdFlush)
+	return err
+}
+
 // NewDestination creates a new real server in the passed ipvs
 // service which should already be existing in the passed handle.
 func (i *Handle) NewDestination(s *Service, d *Destination) error {

vendor/github.com/docker/libnetwork/ipvs/netlink.go

@@ -402,6 +402,13 @@ func (i *Handle) doGetServicesCmd(svc *Service) ([]*Service, error) {
 	return res, nil
 }
 
+// doCmdWithoutAttr a simple wrapper of netlink socket execute command
+func (i *Handle) doCmdWithoutAttr(cmd uint8) ([][]byte, error) {
+	req := newIPVSRequest(cmd)
+	req.Seq = atomic.AddUint32(&i.seq, 1)
+	return execute(i.sock, req, 0)
+}
+
 func assembleDestination(attrs []syscall.NetlinkRouteAttr) (*Destination, error) {
 
 	var d Destination