kube-proxy对于每个pod的snat转换打标和的不应该是放到nat表中的postrouting链里面吗，下面放到kubesep匹配不到吧

[XinyuHu123456]

// 将源 IP 地址标记为 NAT
if err := im.ipt.Insert("nat", kubesep, 1, "-j", "KUBE-MARK-MASQ",
"-s", podIPList[i]+"/"+strconv.Itoa(config.IP_PREFIX_LENGTH)); err != nil {
k8log.ErrorLog("KUBEPROXY", "Failed to create kubesvc chain: "+err.Error())
}