Merge 9a398ccf70 into 4d2aea87f8

Handle attribute NFTNL_SET_DESC_SIZE, as done in libnftnl:
https://git.netfilter.org/libnftnl/tree/src/set.c#n424

Example:
nft add set ip filter myset { type ipv4_addr\; size 65535\; flags dynamic\; }

nftables_test.go

@@ -7816,3 +7816,74 @@ func TestNftablesDeadlock(t *testing.T) {
 		})
 	}
 }
+func TestSetElementComment(t *testing.T) {
+	// Create a new network namespace to test these operations
+	conn, newNS := nftest.OpenSystemConn(t, *enableSysTests)
+	defer nftest.CleanupSystemConn(t, newNS)
+	conn.FlushRuleset()
+	defer conn.FlushRuleset()
+
+	// Add a new table
+	table := &nftables.Table{
+		Family: nftables.TableFamilyIPv4,
+		Name:   "filter",
+	}
+	conn.AddTable(table)
+
+	// Create a new set
+	set := &nftables.Set{
+		Name:    "test-set",
+		Table:   table,
+		KeyType: nftables.TypeIPAddr,
+	}
+
+	// Create set elements with comments
+	elements := []nftables.SetElement{
+		{
+			Key:     net.ParseIP("192.0.2.1").To4(),
+			Comment: "First IP address",
+		},
+		{
+			Key:     net.ParseIP("192.0.2.2").To4(),
+			Comment: "Second IP address",
+		},
+	}
+
+	// Add the set with elements
+	if err := conn.AddSet(set, elements); err != nil {
+		t.Fatalf("failed to add set: %v", err)
+	}
+	if err := conn.Flush(); err != nil {
+		t.Fatalf("failed to flush: %v", err)
+	}
+
+	// Get the set elements back and verify comments
+	gotElements, err := conn.GetSetElements(set)
+	if err != nil {
+		t.Fatalf("failed to get set elements: %v", err)
+	}
+
+	if got, want := len(gotElements), len(elements); got != want {
+		t.Fatalf("got %d elements, want %d", got, want)
+	}
+
+	// Create maps to compare elements by their IP addresses
+	wantMap := make(map[string]string)
+	for _, elem := range elements {
+		wantMap[string(elem.Key)] = elem.Comment
+	}
+
+	gotMap := make(map[string]string)
+	for _, elem := range gotElements {
+		gotMap[string(elem.Key)] = elem.Comment
+	}
+
+	// Compare the comments for each IP
+	for ip, wantComment := range wantMap {
+		if gotComment, ok := gotMap[ip]; !ok {
+			t.Errorf("IP %s not found in retrieved elements", ip)
+		} else if gotComment != wantComment {
+			t.Errorf("for IP %s: got comment %q, want comment %q", ip, gotComment, wantComment)
+		}
+	}
+}

set.go

@@ -267,6 +267,8 @@ type Set struct {
 	// https://git.netfilter.org/nftables/tree/include/datatype.h?id=d486c9e626405e829221b82d7355558005b26d8a#n109
 	KeyByteOrder binaryutil.ByteOrder
 	Comment      string
+	// Indicates that the set has "size" specifier
+	Size uint32
 }
 
 // SetElement represents a data point within a set.
@@ -288,6 +290,7 @@ type SetElement struct {
 	Expires time.Duration
 
 	Counter *expr.Counter
+	Comment string
 }
 
 func (s *SetElement) decode(fam byte) func(b []byte) error {
@@ -322,6 +325,12 @@ func (s *SetElement) decode(fam byte) func(b []byte) error {
 				s.Timeout = time.Millisecond * time.Duration(ad.Uint64())
 			case unix.NFTA_SET_ELEM_EXPIRATION:
 				s.Expires = time.Millisecond * time.Duration(ad.Uint64())
+			case unix.NFTA_SET_ELEM_USERDATA:
+				userData := ad.Bytes()
+				// Try to extract comment from userdata if present
+				if comment, ok := userdata.GetString(userData, userdata.NFTNL_UDATA_SET_ELEM_COMMENT); ok {
+					s.Comment = comment
+				}
 			case unix.NFTA_SET_ELEM_EXPR:
 				elems, err := parseexprfunc.ParseExprBytesFunc(fam, ad)
 				if err != nil {
@@ -454,6 +463,12 @@ func (s *Set) makeElemList(vals []SetElement, id uint32) ([]netlink.Attribute, e
 			// If niether of previous cases matche, it means 'e' is an element of a regular Set, no need to add to the attributes
 		}
 
+		// Add comment to userdata if present
+		if len(v.Comment) > 0 {
+			userData := userdata.AppendString(nil, userdata.NFTNL_UDATA_SET_ELEM_COMMENT, v.Comment)
+			item = append(item, netlink.Attribute{Type: unix.NFTA_SET_ELEM_USERDATA, Data: userData})
+		}
+
 		encodedItem, err := netlink.MarshalAttributes(item)
 		if err != nil {
 			return nil, fmt.Errorf("marshal item %d: %v", i, err)
@@ -553,6 +568,21 @@ func (cc *Conn) AddSet(s *Set, vals []SetElement) error {
 		}
 		tableInfo = append(tableInfo, netlink.Attribute{Type: unix.NLA_F_NESTED | unix.NFTA_SET_DESC, Data: numberOfElements})
 	}
+
+	var descBytes []byte
+
+	if s.Size > 0 {
+		// Marshal set size description
+		descSizeBytes, err := netlink.MarshalAttributes([]netlink.Attribute{
+			{Type: unix.NFTA_SET_DESC_SIZE, Data: binaryutil.BigEndian.PutUint32(s.Size)},
+		})
+		if err != nil {
+			return fmt.Errorf("fail to marshal set size description: %w", err)
+		}
+
+		descBytes = append(descBytes, descSizeBytes...)
+	}
+
 	if s.Concatenation {
 		// Length of concatenated types is a must, otherwise segfaults when executing nft list ruleset
 		var concatDefinition []byte
@@ -579,8 +609,13 @@ func (cc *Conn) AddSet(s *Set, vals []SetElement) error {
 		if err != nil {
 			return fmt.Errorf("fail to marshal concat definition %v", err)
 		}
-		// Marshal concat size description as set description
+
-		tableInfo = append(tableInfo, netlink.Attribute{Type: unix.NLA_F_NESTED | unix.NFTA_SET_DESC, Data: concatBytes})
+		descBytes = append(descBytes, concatBytes...)
+	}
+
+	if len(descBytes) > 0 {
+		// Marshal set description
+		tableInfo = append(tableInfo, netlink.Attribute{Type: unix.NLA_F_NESTED | unix.NFTA_SET_DESC, Data: descBytes})
 	}
 
 	// https://git.netfilter.org/libnftnl/tree/include/udata.h#n17
@@ -734,6 +769,7 @@ func setsFromMsg(msg netlink.Message) (*Set, error) {
 			set.Interval = (flags & unix.NFT_SET_INTERVAL) != 0
 			set.IsMap = (flags & unix.NFT_SET_MAP) != 0
 			set.HasTimeout = (flags & unix.NFT_SET_TIMEOUT) != 0
+			set.Dynamic = (flags & unix.NFT_SET_EVAL) != 0
 			set.Concatenation = (flags & NFT_SET_CONCAT) != 0
 		case unix.NFTA_SET_KEY_TYPE:
 			nftMagic := ad.Uint32()
@@ -762,6 +798,20 @@ func setsFromMsg(msg netlink.Message) (*Set, error) {
 			data := ad.Bytes()
 			value, ok := userdata.GetUint32(data, userdata.NFTNL_UDATA_SET_MERGE_ELEMENTS)
 			set.AutoMerge = ok && value == 1
+		case unix.NFTA_SET_DESC:
+			nestedAD, err := netlink.NewAttributeDecoder(ad.Bytes())
+			if err != nil {
+				return nil, fmt.Errorf("nested NewAttributeDecoder() failed: %w", err)
+			}
+			for nestedAD.Next() {
+				switch nestedAD.Type() {
+				case unix.NFTA_SET_DESC_SIZE:
+					set.Size = binary.BigEndian.Uint32(nestedAD.Bytes())
+				}
+			}
+			if nestedAD.Err() != nil {
+				return nil, fmt.Errorf("decoding set description: %w", nestedAD.Err())
+			}
 		}
 	}
 	return &set, nil
@@ -807,6 +857,7 @@ func elementsFromMsg(fam byte, msg netlink.Message) ([]SetElement, error) {
 		b := ad.Bytes()
 		if ad.Type() == unix.NFTA_SET_ELEM_LIST_ELEMENTS {
 			ad, err := netlink.NewAttributeDecoder(b)
+
 			if err != nil {
 				return nil, err
 			}
@@ -818,6 +869,7 @@ func elementsFromMsg(fam byte, msg netlink.Message) ([]SetElement, error) {
 				case unix.NFTA_LIST_ELEM:
 					ad.Do(elem.decode(fam))
 				}
+
 				elements = append(elements, elem)
 			}
 		}

set_test.go

@@ -1,7 +1,11 @@
 package nftables
 
 import (
+	"reflect"
 	"testing"
+	"time"
+
+	"github.com/mdlayher/netlink"
 )
 
 // unknownNFTMagic is an nftMagic value that's unhandled by this
@@ -185,3 +189,82 @@ func TestConcatSetTypeElements(t *testing.T) {
 		})
 	}
 }
+
+func TestMarshalSet(t *testing.T) {
+	t.Parallel()
+
+	tbl := &Table{
+		Name:   "ipv4table",
+		Family: TableFamilyIPv4,
+	}
+
+	c, err := New(WithTestDial(
+		func(req []netlink.Message) ([]netlink.Message, error) {
+			return req, nil
+		}))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	c.AddTable(tbl)
+
+	// Ensure the table is added.
+	const connMsgStart = 1
+	if len(c.messages) != connMsgStart {
+		t.Fatalf("AddSet() wrong start message count: %d, expected: %d", len(c.messages), connMsgStart)
+	}
+
+	tests := []struct {
+		name string
+		set  Set
+	}{
+		{
+			name: "Set without flags",
+			set: Set{
+				Name:    "test-set",
+				ID:      uint32(1),
+				Table:   tbl,
+				KeyType: TypeIPAddr,
+			},
+		},
+		{
+			name: "Set with size, timeout, dynamic flag specified",
+			set: Set{
+				Name:       "test-set",
+				ID:         uint32(2),
+				HasTimeout: true,
+				Dynamic:    true,
+				Size:       10,
+				Table:      tbl,
+				KeyType:    TypeIPAddr,
+				Timeout:    time.Duration(30) * time.Second,
+			},
+		},
+	}
+
+	for i, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := c.AddSet(&tt.set, nil); err != nil {
+				t.Fatal(err)
+			}
+
+			connMsgSetIdx := connMsgStart + i
+			if len(c.messages) != connMsgSetIdx+1 {
+				t.Fatalf("AddSet() wrong message count: %d, expected: %d", len(c.messages), connMsgSetIdx+1)
+			}
+			msg := c.messages[connMsgSetIdx]
+
+			nset, err := setsFromMsg(msg)
+			if err != nil {
+				t.Fatalf("setsFromMsg() error: %+v", err)
+			}
+
+			// Table pointer is set after flush, which is not implemented in the test.
+			tt.set.Table = nil
+
+			if !reflect.DeepEqual(&tt.set, nset) {
+				t.Fatalf("original %+v and recovered %+v Set structs are different", tt.set, nset)
+			}
+		})
+	}
+}

userdata/userdata.go

@@ -46,6 +46,12 @@ const (
 	NFTNL_UDATA_SET_MAX
 )
 
+// Set element userdata types
+const (
+	NFTNL_UDATA_SET_ELEM_COMMENT Type = iota
+	NFTNL_UDATA_SET_ELEM_FLAGS
+)
+
 func Append(udata []byte, typ Type, data []byte) []byte {
 	udata = append(udata, byte(typ), byte(len(data)))
 	udata = append(udata, data...)