implement CounterObj, AddObj, GetObj, GetObjReset
related to https://github.com/rtr7/router7/issues/3
This commit is contained in:
Michael Stapelberg
parent
beb488f6fa
commit
89ed0f315e
171
nftables.go
171
nftables.go
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@ -420,3 +420,174 @@ func (cc *Conn) GetRule(t *Table, c *Chain) ([]*Rule, error) {
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return rules, nil
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}
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// CounterObj implements Obj.
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type CounterObj struct {
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Table *Table
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Name string // e.g. “fwded”
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Bytes uint64
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Packets uint64
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}
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func (c *CounterObj) unmarshal(attrs []netlink.Attribute) error {
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for _, attr := range attrs {
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switch attr.Type {
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case unix.NFTA_COUNTER_BYTES:
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c.Bytes = binaryutil.BigEndian.Uint64(attr.Data)
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case unix.NFTA_COUNTER_PACKETS:
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c.Packets = binaryutil.BigEndian.Uint64(attr.Data)
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}
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}
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return nil
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}
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func (c *CounterObj) family() TableFamily {
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return c.Table.Family
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}
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func (c *CounterObj) marshal(data bool) ([]byte, error) {
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obj, err := netlink.MarshalAttributes([]netlink.Attribute{
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{Type: unix.NFTA_COUNTER_BYTES, Data: binaryutil.BigEndian.PutUint64(c.Bytes)},
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{Type: unix.NFTA_COUNTER_PACKETS, Data: binaryutil.BigEndian.PutUint64(c.Packets)},
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})
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if err != nil {
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return nil, err
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}
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const NFT_OBJECT_COUNTER = 1 // TODO: get into x/sys/unix
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attrs := []netlink.Attribute{
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{Type: unix.NFTA_OBJ_TABLE, Data: []byte(c.Table.Name + "\x00")},
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{Type: unix.NFTA_OBJ_NAME, Data: []byte(c.Name + "\x00")},
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{Type: unix.NFTA_OBJ_TYPE, Data: binaryutil.BigEndian.PutUint32(NFT_OBJECT_COUNTER)},
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}
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if data {
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attrs = append(attrs, netlink.Attribute{Type: unix.NLA_F_NESTED | unix.NFTA_OBJ_DATA, Data: obj})
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}
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return netlink.MarshalAttributes(attrs)
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}
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// Obj represents a netfilter stateful object. See also
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// https://wiki.nftables.org/wiki-nftables/index.php/Stateful_objects
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type Obj interface {
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family() TableFamily
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unmarshal([]netlink.Attribute) error
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marshal(data bool) ([]byte, error)
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}
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// AddObj adds the specified Obj. See also
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// https://wiki.nftables.org/wiki-nftables/index.php/Stateful_objects
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func (cc *Conn) AddObj(o Obj) Obj {
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data, err := o.marshal(true)
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if err != nil {
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cc.setErr(err)
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return nil
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}
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cc.messages = append(cc.messages, netlink.Message{
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Header: netlink.Header{
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Type: netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_NEWOBJ),
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Flags: netlink.HeaderFlagsRequest | netlink.HeaderFlagsAcknowledge | netlink.HeaderFlagsCreate,
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},
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Data: append(extraHeader(uint8(o.family()), 0), data...),
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})
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return o
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}
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var objHeaderType = netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_NEWOBJ)
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func objFromMsg(msg netlink.Message) (Obj, error) {
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if got, want := msg.Header.Type, objHeaderType; got != want {
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return nil, fmt.Errorf("unexpected header type: got %v, want %v", got, want)
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}
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attrs, err := netlink.UnmarshalAttributes(msg.Data[4:])
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if err != nil {
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return nil, err
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}
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var (
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table *Table
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name string
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objectType uint32
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)
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const NFT_OBJECT_COUNTER = 1 // TODO: get into x/sys/unix
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for _, attr := range attrs {
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switch attr.Type {
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case unix.NFTA_OBJ_TABLE:
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table = &Table{Name: stringFrom0(attr.Data)}
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case unix.NFTA_OBJ_NAME:
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name = stringFrom0(attr.Data)
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case unix.NFTA_OBJ_TYPE:
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objectType = binaryutil.BigEndian.Uint32(attr.Data)
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case unix.NFTA_OBJ_DATA:
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switch objectType {
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case NFT_OBJECT_COUNTER:
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attrs, err := netlink.UnmarshalAttributes(attr.Data)
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if err != nil {
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return nil, err
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}
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o := CounterObj{
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Table: table,
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Name: name,
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}
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return &o, o.unmarshal(attrs)
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}
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}
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}
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return nil, fmt.Errorf("malformed stateful object")
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}
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func (cc *Conn) getObj(o Obj, msgType uint16) ([]Obj, error) {
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var conn *netlink.Conn
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var err error
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if cc.TestDial == nil {
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conn, err = netlink.Dial(unix.NETLINK_NETFILTER, nil)
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} else {
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conn = nltest.Dial(cc.TestDial)
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}
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if err != nil {
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return nil, err
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}
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defer conn.Close()
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data, err := o.marshal(false)
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if err != nil {
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return nil, err
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}
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message := netlink.Message{
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Header: netlink.Header{
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Type: netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | msgType),
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Flags: netlink.HeaderFlagsRequest | netlink.HeaderFlagsAcknowledge | netlink.HeaderFlagsDump,
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},
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Data: append(extraHeader(uint8(o.family()), 0), data...),
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}
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if _, err := conn.SendMessages([]netlink.Message{message}); err != nil {
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return nil, fmt.Errorf("SendMessages: %v", err)
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}
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reply, err := conn.Receive()
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if err != nil {
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return nil, fmt.Errorf("Receive: %v", err)
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}
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var objs []Obj
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for _, msg := range reply {
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o, err := objFromMsg(msg)
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if err != nil {
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return nil, err
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}
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objs = append(objs, o)
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}
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return objs, nil
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}
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// GetObj gets the specified Obj without resetting it.
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func (cc *Conn) GetObj(o Obj) ([]Obj, error) {
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return cc.getObj(o, unix.NFT_MSG_GETOBJ)
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}
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// GetObjReset gets the specified Obj and resets it.
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func (cc *Conn) GetObjReset(o Obj) ([]Obj, error) {
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return cc.getObj(o, unix.NFT_MSG_GETOBJ_RESET)
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}
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132
nftables_test.go
132
nftables_test.go
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@ -329,3 +329,135 @@ func TestGetRule(t *testing.T) {
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t.Errorf("unexpected number of bytes: got %d, want %d", got, want)
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}
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}
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func TestAddCounter(t *testing.T) {
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// The want byte sequences come from stracing nft(8), e.g.:
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// strace -f -v -x -s 2048 -eraw=sendto nft add table ip nat
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//
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// The nft(8) command sequence was taken from:
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// https://wiki.nftables.org/wiki-nftables/index.php/Performing_Network_Address_Translation_(NAT)
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want := [][]byte{
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// batch begin
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[]byte("\x00\x00\x0a\x00"),
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// nft add counter ip filter fwded
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[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x0a\x00\x02\x00\x66\x77\x64\x65\x64\x00\x00\x00\x08\x00\x03\x00\x00\x00\x00\x01\x1c\x00\x04\x80\x0c\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0c\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00"),
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// nft add rule ip filter forward counter name fwded
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[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x0c\x00\x02\x00\x66\x6f\x72\x77\x61\x72\x64\x00\x2c\x00\x04\x80\x28\x00\x01\x80\x0b\x00\x01\x00\x6f\x62\x6a\x72\x65\x66\x00\x00\x18\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x09\x00\x02\x00\x66\x77\x64\x65\x64\x00\x00\x00"),
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// batch end
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[]byte("\x00\x00\x0a\x00"),
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}
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c := &nftables.Conn{
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TestDial: func(req []netlink.Message) ([]netlink.Message, error) {
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for idx, msg := range req {
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b, err := msg.MarshalBinary()
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if err != nil {
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t.Fatal(err)
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}
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if len(b) < 16 {
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continue
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}
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b = b[16:]
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if len(want) == 0 {
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t.Errorf("no want entry for message %d: %x", idx, b)
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continue
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}
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if got, want := b, want[0]; !bytes.Equal(got, want) {
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t.Errorf("message %d: got %x, want %x", idx, got, want)
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}
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want = want[1:]
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}
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return req, nil
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},
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}
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c.AddObj(&nftables.CounterObj{
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Table: &nftables.Table{Name: "filter", Family: nftables.TableFamilyIPv4},
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Name: "fwded",
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Bytes: 0,
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Packets: 0,
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})
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c.AddRule(&nftables.Rule{
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Table: &nftables.Table{Name: "filter", Family: nftables.TableFamilyIPv4},
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Chain: &nftables.Chain{Name: "forward", Type: nftables.ChainTypeFilter},
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Exprs: []expr.Any{
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&expr.Objref{
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Type: 1,
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Name: "fwded",
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},
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},
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})
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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}
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func TestGetObjReset(t *testing.T) {
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// The want byte sequences come from stracing nft(8), e.g.:
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// strace -f -v -x -s 2048 -eraw=sendto nft list chain ip filter forward
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want := [][]byte{
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[]byte{0x2, 0x0, 0x0, 0x0, 0xb, 0x0, 0x1, 0x0, 0x66, 0x69, 0x6c, 0x74, 0x65, 0x72, 0x0, 0x0, 0xa, 0x0, 0x2, 0x0, 0x66, 0x77, 0x64, 0x65, 0x64, 0x0, 0x0, 0x0, 0x8, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0, 0x1},
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}
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// The reply messages come from adding log.Printf("msgs: %#v", msgs) to
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// (*github.com/mdlayher/netlink/Conn).receive
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reply := [][]netlink.Message{
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nil,
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[]netlink.Message{netlink.Message{Header: netlink.Header{Length: 0x64, Type: 0xa12, Flags: 0x802, Sequence: 0x9acb0443, PID: 0xde9}, Data: []uint8{0x2, 0x0, 0x0, 0x10, 0xb, 0x0, 0x1, 0x0, 0x66, 0x69, 0x6c, 0x74, 0x65, 0x72, 0x0, 0x0, 0xa, 0x0, 0x2, 0x0, 0x66, 0x77, 0x64, 0x65, 0x64, 0x0, 0x0, 0x0, 0x8, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0, 0x1, 0x8, 0x0, 0x5, 0x0, 0x0, 0x0, 0x0, 0x1, 0x1c, 0x0, 0x4, 0x0, 0xc, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x4, 0x61, 0xc, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x9, 0xc, 0x0, 0x6, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2}}},
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[]netlink.Message{netlink.Message{Header: netlink.Header{Length: 0x14, Type: 0x3, Flags: 0x2, Sequence: 0x9acb0443, PID: 0xde9}, Data: []uint8{0x0, 0x0, 0x0, 0x0}}},
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}
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c := &nftables.Conn{
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TestDial: func(req []netlink.Message) ([]netlink.Message, error) {
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for idx, msg := range req {
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b, err := msg.MarshalBinary()
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if err != nil {
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t.Fatal(err)
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}
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if len(b) < 16 {
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continue
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}
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b = b[16:]
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if len(want) == 0 {
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t.Errorf("no want entry for message %d: %x", idx, b)
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continue
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}
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if got, want := b, want[0]; !bytes.Equal(got, want) {
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t.Errorf("message %d: got %#v, want %#v", idx, got, want)
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}
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want = want[1:]
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}
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rep := reply[0]
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reply = reply[1:]
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return rep, nil
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},
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}
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objs, err := c.GetObjReset(&nftables.CounterObj{
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Table: &nftables.Table{Name: "filter", Family: nftables.TableFamilyIPv4},
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Name: "fwded",
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})
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if err != nil {
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t.Fatal(err)
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}
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if got, want := len(objs), 1; got != want {
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t.Fatalf("unexpected number of rules: got %d, want %d", got, want)
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}
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obj := objs[0]
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co, ok := obj.(*nftables.CounterObj)
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if !ok {
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t.Fatalf("unexpected type: got %T, want *nftables.CounterObj", obj)
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}
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if got, want := co.Packets, uint64(9); got != want {
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t.Errorf("unexpected number of packets: got %d, want %d", got, want)
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}
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if got, want := co.Bytes, uint64(1121); got != want {
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t.Errorf("unexpected number of bytes: got %d, want %d", got, want)
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}
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}
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