add DelTable(force)

nftables_test.go

@@ -128,6 +128,48 @@ func ifname(n string) []byte {
 	return b
 }
 
+func TestTableCreateDestroy(t *testing.T) {
+	c, newNS := nftest.OpenSystemConn(t, *enableSysTests)
+	defer nftest.CleanupSystemConn(t, newNS)
+	defer c.FlushRuleset()
+
+	filter := &nftables.Table{
+		Family: nftables.TableFamilyIPv4,
+		Name:   "filter",
+	}
+	c.DelTable(filter, true)
+	c.AddTable(filter)
+	err := c.Flush()
+	if err != nil {
+		t.Fatalf("on Flush: %q", err.Error())
+	}
+
+	LookupMyTable := func() bool {
+		ts, err := c.ListTables()
+		if err != nil {
+			t.Fatalf("on ListTables: %q", err.Error())
+		}
+		return slices.ContainsFunc(ts, func(t *nftables.Table) bool {
+			return t.Name == filter.Name && t.Family == filter.Family
+		})
+	}
+	if !LookupMyTable() {
+		t.Fatal("AddTable doesn't create my table!")
+	}
+
+	c.DelTable(filter)
+	err = c.Flush()
+	if err != nil {
+		t.Fatalf("on Flush: %q", err.Error())
+	}
+
+	if LookupMyTable() {
+		t.Fatal("DelTable doesn't delete my table!")
+	}
+
+	c.DelTable(filter, true) // just for test that 'force' ignore error 'not found'
+}
+
 func TestRuleOperations(t *testing.T) {
 	// Create a new network namespace to test these operations,
 	// and tear down the namespace at test completion.

table.go

@@ -16,6 +16,7 @@ package nftables
 
 import (
 	"fmt"
+	"slices"
 
 	"github.com/mdlayher/netlink"
 	"golang.org/x/sys/unix"
@@ -24,6 +25,10 @@ import (
 const (
 	newTableHeaderType = netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_NEWTABLE)
 	delTableHeaderType = netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_DELTABLE)
+
+	// FIXME: in sys@v0.34.0 no unix.NFT_MSG_DESTROYTABLE const yet.
+	// See nf_tables_msg_types enum in https://git.netfilter.org/nftables/tree/include/linux/netfilter/nf_tables.h
+	destroyTableHeaderType = netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | 0x1a)
 )
 
 // TableFamily specifies the address family for this table.
@@ -50,16 +55,23 @@ type Table struct {
 }
 
 // DelTable deletes a specific table, along with all chains/rules it contains.
-func (cc *Conn) DelTable(t *Table) {
+func (cc *Conn) DelTable(t *Table, force ...bool) {
 	cc.mu.Lock()
 	defer cc.mu.Unlock()
 	data := cc.marshalAttr([]netlink.Attribute{
 		{Type: unix.NFTA_TABLE_NAME, Data: []byte(t.Name + "\x00")},
 		{Type: unix.NFTA_TABLE_FLAGS, Data: []byte{0, 0, 0, 0}},
 	})
+
+	var hdrType netlink.HeaderType
+	if slices.Contains(force, true) {
+		hdrType = destroyTableHeaderType
+	} else {
+		hdrType = delTableHeaderType
+	}
 	cc.messages = append(cc.messages, netlinkMessage{
 		Header: netlink.Header{
-			Type:  netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_DELTABLE),
+			Type:  hdrType,
 			Flags: netlink.Request | netlink.Acknowledge,
 		},
 		Data: append(extraHeader(uint8(t.Family), 0), data...),