Add flowtable counter support

fake_test.go

@@ -667,6 +667,8 @@ func TestFakeParseDump(t *testing.T) {
 			dump: `
 				add table ip test
 				add flowtable ip test myflowtable { hook ingress priority filter ; devices = { eth0, eth1 } ; }
+				add flowtable ip test countedflowtable { hook ingress priority filter ; devices = { eth2 } ; counter ; }
+				add flowtable ip test nodevflowtable { hook ingress priority filter ; counter ; }
 				add chain ip test anotherchain
 				add chain ip test chain { comment "foo" ; }
 				add map ip test map1 { type ipv4_addr . inet_proto . inet_service ; }

objects.go

@@ -730,15 +730,20 @@ func (flowtable *Flowtable) writeOperation(verb verb, ctx *nftContext, writer io
 			fmt.Fprintf(writer, " devices = { %s } ;", strings.Join(flowtable.Devices, ", "))
 		}
 
+		if flowtable.Counter != nil && *flowtable.Counter {
+			fmt.Fprintf(writer, " counter ;")
+		}
+
 		fmt.Fprintf(writer, " }")
 	}
 
 	fmt.Fprintf(writer, "\n")
 }
 
-// nft add flowtable inet example_table example_flowtable { hook ingress priority filter ; devices = { eth0 };  }
+// nft add flowtable inet example_table example_flowtable { hook ingress priority filter ; devices = { eth0 } ; counter ; }
+// Every property is optional, so a flowtable may have a counter and no devices.
 var flowtableRegexp = regexp.MustCompile(fmt.Sprintf(
-	`%s(?: {(?: hook ingress priority %s ;)(?: devices = {(.*)} ;) })?`,
+	`%s(?: {(?: hook ingress priority %s ;)?(?: devices = {(.*)} ;)?( counter ;)? })?`,
 	noSpaceGroup, noSpaceGroup))
 
 func (flowtable *Flowtable) parse(family Family, table, line string) error {
@@ -764,6 +769,9 @@ func (flowtable *Flowtable) parse(family Family, table, line string) error {
 			flowtable.Devices = devices
 		}
 	}
+	if match[4] != "" {
+		flowtable.Counter = PtrTo(true)
+	}
 	return nil
 }
 

objects_test.go

@@ -167,6 +167,27 @@ func TestObjects(t *testing.T) {
 			},
 			out: `create flowtable ip mytable myflowtable { hook ingress priority filter ; devices = { eth0, eth1 } ; }`,
 		},
+		{
+			name: "create flowtable with counter",
+			verb: createVerb,
+			object: &Flowtable{
+				Name:     "myflowtable",
+				Priority: PtrTo(FilterIngressPriority),
+				Devices:  []string{"eth0", "eth1"},
+				Counter:  PtrTo(true),
+			},
+			out: `create flowtable ip mytable myflowtable { hook ingress priority filter ; devices = { eth0, eth1 } ; counter ; }`,
+		},
+		{
+			name: "create flowtable with counter and no devices",
+			verb: createVerb,
+			object: &Flowtable{
+				Name:     "myflowtable",
+				Priority: PtrTo(FilterIngressPriority),
+				Counter:  PtrTo(true),
+			},
+			out: `create flowtable ip mytable myflowtable { hook ingress priority filter ; counter ; }`,
+		},
 		{
 			name: "flush flowtable",
 			verb: flushVerb,

types.go

@@ -496,6 +496,10 @@ type Flowtable struct {
 	// that should be offloaded.
 	Devices []string
 
+	// Counter enables packet and byte accounting for offloaded flows.
+	// (Optional; requires kernel 5.13 or later)
+	Counter *bool
+
 	// Handle is an identifier that can be used to uniquely identify an object when
 	// deleting it. When adding a new object, this must be nil
 	Handle *int