Allow setting of source CIDR for LB rule

    * Annotation added to allow setting of Source CIDR for Load Balancer
      rule

Author: CodeBleu

cloudstack_loadbalancer.go

@@ -22,6 +22,7 @@ package cloudstack
 import (
 	"context"
 	"fmt"
+	"net"
 	"strconv"
 	"strings"
 
@@ -41,9 +42,9 @@ const (
 	// service to enable the proxy protocol on a CloudStack load balancer.
 	// Note that this protocol only applies to TCP service ports and
 	// CloudStack >= 4.6 is required for it to work.
-	ServiceAnnotationLoadBalancerProxyProtocol = "service.beta.kubernetes.io/cloudstack-load-balancer-proxy-protocol"
-
+	ServiceAnnotationLoadBalancerProxyProtocol        = "service.beta.kubernetes.io/cloudstack-load-balancer-proxy-protocol"
 	ServiceAnnotationLoadBalancerLoadbalancerHostname = "service.beta.kubernetes.io/cloudstack-load-balancer-hostname"
+	ServiceAnnotationLoadBalancerSourceCidrs          = "service.beta.kubernetes.io/cloudstack-load-balancer-source-cidrs"
 )
 
 type loadBalancer struct {
@@ -162,7 +163,7 @@ func (cs *CSCloud) EnsureLoadBalancer(ctx context.Context, clusterName string, s
 			}
 		} else {
 			klog.V(4).Infof("Creating load balancer rule: %v", lbRuleName)
-			lbRule, err = lb.createLoadBalancerRule(lbRuleName, port, protocol)
+			lbRule, err = lb.createLoadBalancerRule(lbRuleName, port, protocol, service)
 			if err != nil {
 				return nil, err
 			}
@@ -596,7 +597,7 @@ func (lb *loadBalancer) updateLoadBalancerRule(lbRuleName string, protocol LoadB
 }
 
 // createLoadBalancerRule creates a new load balancer rule and returns it's ID.
-func (lb *loadBalancer) createLoadBalancerRule(lbRuleName string, port corev1.ServicePort, protocol LoadBalancerProtocol) (*cloudstack.LoadBalancerRule, error) {
+func (lb *loadBalancer) createLoadBalancerRule(lbRuleName string, port corev1.ServicePort, protocol LoadBalancerProtocol, service *corev1.Service) (*cloudstack.LoadBalancerRule, error) {
 	p := lb.LoadBalancer.NewCreateLoadBalancerRuleParams(
 		lb.algorithm,
 		lbRuleName,
@@ -606,12 +607,30 @@ func (lb *loadBalancer) createLoadBalancerRule(lbRuleName string, port corev1.Se
 
 	p.SetNetworkid(lb.networkID)
 	p.SetPublicipid(lb.ipAddrID)
-
 	p.SetProtocol(protocol.CSProtocol())
 
 	// Do not open the firewall implicitly, we always create explicit firewall rules
 	p.SetOpenfirewall(false)
 
+	// Read the source CIDR annotation
+	sourceCIDRs, ok := service.Annotations[ServiceAnnotationLoadBalancerSourceCidrs]
+	var cidrList []string
+	if ok && sourceCIDRs != "" {
+		cidrList = strings.Split(sourceCIDRs, ",")
+		for i, cidr := range cidrList {
+			cidr = strings.TrimSpace(cidr)
+			if _, _, err := net.ParseCIDR(cidr); err != nil {
+				return nil, fmt.Errorf("invalid CIDR in annotation %s: %s", ServiceAnnotationLoadBalancerSourceCidrs, cidr)
+			}
+			cidrList[i] = cidr
+		}
+	} else {
+		cidrList = []string{defaultAllowedCIDR}
+	}
+
+	// Set the CIDR list in the parameters
+	p.SetCidrlist(cidrList)
+
 	// Create a new load balancer rule.
 	r, err := lb.LoadBalancer.CreateLoadBalancerRule(p)
 	if err != nil {