Do not generate nftables chains for network policies if FilterTableName is empty

docs/agent/environments/vyos.md

@@ -4,7 +4,7 @@ This page describes the requirements for running the LBaaS-agent on a VyOS host.
 
 ## Requirements
 
-- VyOS 1.3 (1.4 probably also works with some config changes)
+- VyOS >= 1.3
 - L3-connection to the k8s-cluster
     - For example by establishing BGP peerings with the kubernetes nodes (see below)
 - At least one configured SNAT or DNAT rule via the VyOS configuration interface 
@@ -24,6 +24,7 @@ This page describes the requirements for running the LBaaS-agent on a VyOS host.
 ```toml
 bind-address="0.0.0.0"
 bind-port=15203
+shared-secret="changeme"
 
 [keepalived]
 enabled=false
@@ -47,8 +48,34 @@ status-command=["true"]
 start-command=["sudo", "nft", "-f", "/var/lib/ch-k8s-lbaas-agent/nftables/lbaas.conf"]
 ```
 
-__Warning:__ With VyOS 1.4, the names of the nftables hook changed.
+### VyOS >= 1.4
 
+```toml
+bind-address="0.0.0.0"
+bind-port=15203
+shared-secret="changeme"
+
+[keepalived]
+enabled=false
+
+[nftables]
+filter-table-name="" # "vyos_filter" in VyOS 1.4, but there are no hook-chains as in 1.3 -> Let empty to disable filtering
+filter-table-type="ip"
+filter-forward-chain="" # Does not exist by default in VyOS 1.4, must be created if wanted
+nat-table-name="vyos_nat"
+nat-prerouting-chain="VYOS_PRE_DNAT_HOOK"
+nat-postrouting-chain="VYOS_PRE_SNAT_HOOK"
+partial-reload=true
+policy-prefix="lbaas-"
+nft-command=["sudo","nft"]
+enable-snat=true
+
+[nftables.service]
+config-file="/var/lib/ch-k8s-lbaas-agent/nftables/lbaas.conf"
+reload-command=["sudo", "nft", "-f", "/var/lib/ch-k8s-lbaas-agent/nftables/lbaas.conf"]
+status-command=["true"]
+start-command=["sudo", "nft", "-f", "/var/lib/ch-k8s-lbaas-agent/nftables/lbaas.conf"]
+```
 
 ## BGP Configuration
 

internal/agent/nftables_generator.go

@@ -42,6 +42,8 @@ var (
 # When partial reload is enabled, flush chains.
 flush chain ip {{ .NATTableName }} {{ .NATPreroutingChainName }}
 flush chain ip {{ .NATTableName }} {{ .NATPostroutingChainName }}
+
+{{- if ne .FilterTableName "" }}
 flush chain {{ .FilterTableType }} {{ .FilterTableName }} {{ .FilterForwardChainName }}
 
 # Also delete all existing policy chains. 
@@ -53,7 +55,9 @@ add chain {{ $cfg.FilterTableType }} {{ $cfg.FilterTableName }} {{ $chain }}
 delete chain {{ $cfg.FilterTableType }} {{ $cfg.FilterTableName }} {{ $chain }}
 {{- end }}
 {{- end }}
+{{- end }}
 
+{{- if ne .FilterTableName "" }}
 table {{ .FilterTableType }} {{ .FilterTableName }} {
 	chain {{ .FilterForwardChainName }} {
 		{{- range $dest := $cfg.PolicyAssignments }}
@@ -103,6 +107,7 @@ table {{ .FilterTableType }} {{ .FilterTableName }} {
 
 	{{- end }}
 }
+{{- end }}
 
 table ip {{ .NATTableName }} {
 	chain {{ .NATPreroutingChainName }} {
@@ -489,22 +494,25 @@ func (g *NftablesGenerator) GenerateStructuredConfig(m *model.LoadBalancer) (*nf
 		return fwdA.InboundPort < fwdB.InboundPort
 	})
 
-	result.PolicyAssignments = copyPolicyAssignment(m.PolicyAssignments)
-	policies, err := copyNetworkPolicies(m.NetworkPolicies)
-	if err != nil {
-		return nil, err
-	}
-	for _, policy := range policies {
-		result.NetworkPolicies[policy.Name] = policy
-	}
+	if g.Cfg.FilterTableName != "" {
+		result.PolicyAssignments = copyPolicyAssignment(m.PolicyAssignments)
+		policies, err := copyNetworkPolicies(m.NetworkPolicies)
+		if err != nil {
+			return nil, err
+		}
+		for _, policy := range policies {
+			result.NetworkPolicies[policy.Name] = policy
+		}
 
-	if g.Cfg.PartialReload {
-		// When partial reload is enabled, get all existing policy chain names to delete them in the template
-		result.ExistingPolicyChains, err = getExistingPolicyChains(
-			g.Cfg.NftCommand,
-			g.Cfg.FilterTableName,
-			g.Cfg.FilterTableType,
-			g.Cfg.PolicyPrefix)
+		if g.Cfg.PartialReload {
+			// When partial reload is enabled, get all existing policy chain names to delete
+			// them in the template
+			result.ExistingPolicyChains, err = getExistingPolicyChains(
+				g.Cfg.NftCommand,
+				g.Cfg.FilterTableName,
+				g.Cfg.FilterTableType,
+				g.Cfg.PolicyPrefix)
+		}
 	}
 
 	return result, nil

internal/agent/nftables_generator_test.go

@@ -27,16 +27,21 @@ import (
 	"github.com/cloudandheat/ch-k8s-lbaas/internal/model"
 )
 
-func newNftablesGenerator() *NftablesGenerator {
+func newNftablesGenerator(noFilterTable bool) *NftablesGenerator {
 	cfg := &config.Nftables{}
 	config.FillNftablesConfig(cfg)
+
+	if noFilterTable {
+		cfg.FilterTableName = ""
+	}
+
 	return &NftablesGenerator{
 		Cfg: *cfg,
 	}
 }
 
 func TestNftablesStructuredConfigFromEmptyLBModel(t *testing.T) {
-	g := newNftablesGenerator()
+	g := newNftablesGenerator(false)
 
 	m := &model.LoadBalancer{
 		Ingress: []model.IngressIP{},
@@ -58,7 +63,7 @@ func TestNftablesStructuredConfigFromEmptyLBModel(t *testing.T) {
 }
 
 func TestNftablesStructuredConfigFromNonEmptyLBModel(t *testing.T) {
-	g := newNftablesGenerator()
+	g := newNftablesGenerator(false)
 
 	m := &model.LoadBalancer{
 		Ingress: []model.IngressIP{
@@ -222,7 +227,7 @@ func TestNftablesStructuredConfigFromNonEmptyLBModel(t *testing.T) {
 }
 
 func TestNftablesStructuredConfigSortsAddresses(t *testing.T) {
-	g := newNftablesGenerator()
+	g := newNftablesGenerator(false)
 
 	m := &model.LoadBalancer{
 		Ingress: []model.IngressIP{
@@ -330,3 +335,56 @@ func TestFilterNftablesChainListByPrefix(t *testing.T) {
 
 	assert.Equal(t, []string{"Prefix-TestChain1"}, filteredChains)
 }
+
+func TestNftablesStructuredConfigWithDisabledPolicies(t *testing.T) {
+	g := newNftablesGenerator(true)
+
+	m := &model.LoadBalancer{
+		Ingress: []model.IngressIP{
+			{
+				Address: "172.23.42.1",
+				Ports: []model.PortForward{
+					{
+						InboundPort:          80,
+						Protocol:             corev1.ProtocolTCP,
+						DestinationPort:      30080,
+						DestinationAddresses: []string{"192.168.0.1", "192.168.0.2"},
+					},
+				},
+			},
+		},
+		NetworkPolicies: []model.NetworkPolicy{
+			{
+				Name: "block-range",
+				AllowedIngresses: []model.AllowedIngress{
+					{
+						IPBlockFilters: []model.IPBlockFilter{
+							{
+								Allow: "0.0.0.0/0",
+								Block: []string{
+									"192.168.2.0/24",
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		PolicyAssignments: []model.PolicyAssignment{
+			{
+				Address: "192.168.0.2",
+				NetworkPolicies: []string{
+					"block-range",
+				},
+			},
+		},
+	}
+
+	scfg, err := g.GenerateStructuredConfig(m)
+	assert.Nil(t, err)
+	assert.NotNil(t, scfg)
+	assert.NotNil(t, scfg.Forwards)
+	assert.Equal(t, 1, len(scfg.Forwards))
+	assert.NotNil(t, scfg.NetworkPolicies)
+	assert.Equal(t, 0, len(scfg.NetworkPolicies))
+}