diff --git a/expr/bitwise.go b/expr/bitwise.go new file mode 100644 index 0000000..6196da6 --- /dev/null +++ b/expr/bitwise.go @@ -0,0 +1,65 @@ +// Copyright 2018 Google LLC. All Rights Reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package expr + +import ( + "fmt" + + "github.com/google/nftables/binaryutil" + "github.com/mdlayher/netlink" + "golang.org/x/sys/unix" +) + +type Bitwise struct { + SourceRegister uint32 + DestRegister uint32 + Len uint32 + Mask []byte + Xor []byte +} + +func (e *Bitwise) marshal() ([]byte, error) { + mask, err := netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_DATA_VALUE, Data: e.Mask}, + }) + if err != nil { + return nil, err + } + xor, err := netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_DATA_VALUE, Data: e.Xor}, + }) + if err != nil { + return nil, err + } + + data, err := netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_BITWISE_SREG, Data: binaryutil.BigEndian.PutUint32(e.SourceRegister)}, + {Type: unix.NFTA_BITWISE_DREG, Data: binaryutil.BigEndian.PutUint32(e.DestRegister)}, + {Type: unix.NFTA_BITWISE_LEN, Data: binaryutil.BigEndian.PutUint32(e.Len)}, + {Type: unix.NLA_F_NESTED | unix.NFTA_BITWISE_MASK, Data: mask}, + {Type: unix.NLA_F_NESTED | unix.NFTA_BITWISE_XOR, Data: xor}, + }) + if err != nil { + return nil, err + } + return netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_EXPR_NAME, Data: []byte("bitwise\x00")}, + {Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data}, + }) +} + +func (e *Bitwise) unmarshal(data []byte) error { + return fmt.Errorf("not yet implemented") +} diff --git a/expr/byteorder.go b/expr/byteorder.go new file mode 100644 index 0000000..a28996d --- /dev/null +++ b/expr/byteorder.go @@ -0,0 +1,59 @@ +// Copyright 2018 Google LLC. All Rights Reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package expr + +import ( + "fmt" + + "github.com/google/nftables/binaryutil" + "github.com/mdlayher/netlink" + "golang.org/x/sys/unix" +) + +type ByteorderOp uint32 + +const ( + ByteorderNtoh ByteorderOp = unix.NFT_BYTEORDER_NTOH + ByteorderHton ByteorderOp = unix.NFT_BYTEORDER_HTON +) + +type Byteorder struct { + SourceRegister uint32 + DestRegister uint32 + Op ByteorderOp + Len uint32 + Size uint32 +} + +func (e *Byteorder) marshal() ([]byte, error) { + data, err := netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_BYTEORDER_SREG, Data: binaryutil.BigEndian.PutUint32(e.SourceRegister)}, + {Type: unix.NFTA_BYTEORDER_DREG, Data: binaryutil.BigEndian.PutUint32(e.DestRegister)}, + {Type: unix.NFTA_BYTEORDER_OP, Data: binaryutil.BigEndian.PutUint32(uint32(e.Op))}, + {Type: unix.NFTA_BYTEORDER_LEN, Data: binaryutil.BigEndian.PutUint32(e.Len)}, + {Type: unix.NFTA_BYTEORDER_SIZE, Data: binaryutil.BigEndian.PutUint32(e.Size)}, + }) + if err != nil { + return nil, err + } + return netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_EXPR_NAME, Data: []byte("byteorder\x00")}, + {Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data}, + }) +} + +func (e *Byteorder) unmarshal(data []byte) error { + return fmt.Errorf("not yet implemented") +} diff --git a/expr/exthdr.go b/expr/exthdr.go new file mode 100644 index 0000000..e47f268 --- /dev/null +++ b/expr/exthdr.go @@ -0,0 +1,64 @@ +// Copyright 2018 Google LLC. All Rights Reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package expr + +import ( + "fmt" + + "github.com/google/nftables/binaryutil" + "github.com/mdlayher/netlink" + "golang.org/x/sys/unix" +) + +type ExthdrOp uint32 + +const ( + ExthdrOpIpv6 ExthdrOp = unix.NFT_EXTHDR_OP_IPV6 + ExthdrOpTcpopt ExthdrOp = unix.NFT_EXTHDR_OP_TCPOPT +) + +type Exthdr struct { + DestRegister uint32 + Type uint8 + Offset uint32 + Len uint32 + Flags uint32 + Op ExthdrOp + SourceRegister uint32 +} + +func (e *Exthdr) marshal() ([]byte, error) { + data, err := netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_EXTHDR_SREG, Data: binaryutil.BigEndian.PutUint32(e.SourceRegister)}, + {Type: unix.NFTA_EXTHDR_TYPE, Data: []byte{e.Type}}, + {Type: unix.NFTA_EXTHDR_OFFSET, Data: binaryutil.BigEndian.PutUint32(e.Offset)}, + {Type: unix.NFTA_EXTHDR_LEN, Data: binaryutil.BigEndian.PutUint32(e.Len)}, + // TODO: these fields seem to be conditional? + //{Type: unix.NFTA_EXTHDR_DREG, Data: binaryutil.BigEndian.PutUint32(e.DestRegister)}, + //{Type: unix.NFTA_EXTHDR_FLAGS, Data: binaryutil.BigEndian.PutUint32(e.Flags)}, + {Type: unix.NFTA_EXTHDR_OP, Data: binaryutil.BigEndian.PutUint32(uint32(e.Op))}, + }) + if err != nil { + return nil, err + } + return netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_EXPR_NAME, Data: []byte("exthdr\x00")}, + {Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data}, + }) +} + +func (e *Exthdr) unmarshal(data []byte) error { + return fmt.Errorf("not yet implemented") +} diff --git a/expr/rt.go b/expr/rt.go new file mode 100644 index 0000000..8fdbdb5 --- /dev/null +++ b/expr/rt.go @@ -0,0 +1,55 @@ +// Copyright 2018 Google LLC. All Rights Reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package expr + +import ( + "fmt" + + "github.com/google/nftables/binaryutil" + "github.com/mdlayher/netlink" + "golang.org/x/sys/unix" +) + +type RtKey uint32 + +const ( + RtClassid RtKey = unix.NFT_RT_CLASSID + RtNexthop4 RtKey = unix.NFT_RT_NEXTHOP4 + RtNexthop6 RtKey = unix.NFT_RT_NEXTHOP6 + RtTCPMSS RtKey = unix.NFT_RT_TCPMSS +) + +type Rt struct { + Register uint32 + Key RtKey +} + +func (e *Rt) marshal() ([]byte, error) { + data, err := netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_RT_KEY, Data: binaryutil.BigEndian.PutUint32(uint32(e.Key))}, + {Type: unix.NFTA_RT_DREG, Data: binaryutil.BigEndian.PutUint32(e.Register)}, + }) + if err != nil { + return nil, err + } + return netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_EXPR_NAME, Data: []byte("rt\x00")}, + {Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data}, + }) +} + +func (e *Rt) unmarshal(data []byte) error { + return fmt.Errorf("not yet implemented") +} diff --git a/nftables_test.go b/nftables_test.go index 3af63a7..5290219 100644 --- a/nftables_test.go +++ b/nftables_test.go @@ -16,7 +16,9 @@ package nftables_test import ( "bytes" + "fmt" "net" + "strings" "testing" "github.com/google/nftables" @@ -26,6 +28,46 @@ import ( "golang.org/x/sys/unix" ) +// nfdump returns a hexdump of 4 bytes per line (like nft --debug=all), allowing +// users to make sense of large byte literals more easily. +func nfdump(b []byte) string { + var buf bytes.Buffer + i := 0 + for ; i < len(b); i += 4 { + // TODO: show printable characters as ASCII + fmt.Fprintf(&buf, "%02x %02x %02x %02x\n", + b[i], + b[i+1], + b[i+2], + b[i+3]) + } + for ; i < len(b); i++ { + fmt.Fprintf(&buf, "%02x ", b[i]) + } + return buf.String() +} + +// linediff returns a side-by-side diff of two nfdump() return values, flagging +// lines which are not equal with an exclamation point prefix. +func linediff(a, b string) string { + var buf bytes.Buffer + fmt.Fprintf(&buf, "got -- want\n") + linesA := strings.Split(a, "\n") + linesB := strings.Split(b, "\n") + for idx, lineA := range linesA { + if idx >= len(linesB) { + break + } + lineB := linesB[idx] + prefix := "! " + if lineA == lineB { + prefix = " " + } + fmt.Fprintf(&buf, "%s%s -- %s\n", prefix, lineA, lineB) + } + return buf.String() +} + func ifname(n string) []byte { b := make([]byte, 16) copy(b, []byte(n+"\x00")) @@ -75,7 +117,7 @@ func TestConfigureNAT(t *testing.T) { continue } if got, want := b, want[0]; !bytes.Equal(got, want) { - t.Errorf("message %d: got %x, want %x", idx, got, want) + t.Errorf("message %d: %s", idx, linediff(nfdump(got), nfdump(want))) } want = want[1:] } @@ -284,7 +326,7 @@ func TestGetRule(t *testing.T) { continue } if got, want := b, want[0]; !bytes.Equal(got, want) { - t.Errorf("message %d: got %#v, want %#v", idx, got, want) + t.Errorf("message %d: %s", idx, linediff(nfdump(got), nfdump(want))) } want = want[1:] } @@ -363,7 +405,7 @@ func TestAddCounter(t *testing.T) { continue } if got, want := b, want[0]; !bytes.Equal(got, want) { - t.Errorf("message %d: got %x, want %x", idx, got, want) + t.Errorf("message %d: %s", idx, linediff(nfdump(got), nfdump(want))) } want = want[1:] } @@ -426,7 +468,7 @@ func TestGetObjReset(t *testing.T) { continue } if got, want := b, want[0]; !bytes.Equal(got, want) { - t.Errorf("message %d: got %#v, want %#v", idx, got, want) + t.Errorf("message %d: %s", idx, linediff(nfdump(got), nfdump(want))) } want = want[1:] } @@ -468,3 +510,136 @@ func TestGetObjReset(t *testing.T) { t.Errorf("unexpected number of bytes: got %d, want %d", got, want) } } + +func TestConfigureClamping(t *testing.T) { + // The want byte sequences come from stracing nft(8), e.g.: + // strace -f -v -x -s 2048 -eraw=sendto nft add table ip nat + // + // The nft(8) command sequence was taken from: + // https://wiki.nftables.org/wiki-nftables/index.php/Mangle_TCP_options + want := [][]byte{ + // batch begin + []byte("\x00\x00\x00\x0a"), + // nft flush ruleset + []byte("\x00\x00\x00\x00"), + // nft add table ip filter + []byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x08\x00\x02\x00\x00\x00\x00\x00"), + // nft add chain filter forward '{' type filter hook forward priority 0 \; '}' + []byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x0c\x00\x03\x00\x66\x6f\x72\x77\x61\x72\x64\x00\x14\x00\x04\x80\x08\x00\x01\x00\x00\x00\x00\x02\x08\x00\x02\x00\x00\x00\x00\x00\x0b\x00\x07\x00\x66\x69\x6c\x74\x65\x72\x00\x00"), + // nft add rule ip filter forward oifname uplink0 tcp flags syn tcp option maxseg size set rt mtu + []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\xf0\x01\x04\x80\x24\x00\x01\x80\x09\x00\x01\x00\x6d\x65\x74\x61\x00\x00\x00\x00\x14\x00\x02\x80\x08\x00\x02\x00\x00\x00\x00\x07\x08\x00\x01\x00\x00\x00\x00\x01\x38\x00\x01\x80\x08\x00\x01\x00\x63\x6d\x70\x00\x2c\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x08\x00\x02\x00\x00\x00\x00\x00\x18\x00\x03\x80\x14\x00\x01\x00\x75\x70\x6c\x69\x6e\x6b\x30\x00\x00\x00\x00\x00\x00\x00\x00\x00\x24\x00\x01\x80\x09\x00\x01\x00\x6d\x65\x74\x61\x00\x00\x00\x00\x14\x00\x02\x80\x08\x00\x02\x00\x00\x00\x00\x10\x08\x00\x01\x00\x00\x00\x00\x01\x2c\x00\x01\x80\x08\x00\x01\x00\x63\x6d\x70\x00\x20\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x08\x00\x02\x00\x00\x00\x00\x00\x0c\x00\x03\x80\x05\x00\x01\x00\x06\x00\x00\x00\x34\x00\x01\x80\x0c\x00\x01\x00\x70\x61\x79\x6c\x6f\x61\x64\x00\x24\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x08\x00\x02\x00\x00\x00\x00\x02\x08\x00\x03\x00\x00\x00\x00\x0d\x08\x00\x04\x00\x00\x00\x00\x01\x44\x00\x01\x80\x0c\x00\x01\x00\x62\x69\x74\x77\x69\x73\x65\x00\x34\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x08\x00\x02\x00\x00\x00\x00\x01\x08\x00\x03\x00\x00\x00\x00\x01\x0c\x00\x04\x80\x05\x00\x01\x00\x02\x00\x00\x00\x0c\x00\x05\x80\x05\x00\x01\x00\x00\x00\x00\x00\x2c\x00\x01\x80\x08\x00\x01\x00\x63\x6d\x70\x00\x20\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x08\x00\x02\x00\x00\x00\x00\x01\x0c\x00\x03\x80\x05\x00\x01\x00\x00\x00\x00\x00\x20\x00\x01\x80\x07\x00\x01\x00\x72\x74\x00\x00\x14\x00\x02\x80\x08\x00\x02\x00\x00\x00\x00\x03\x08\x00\x01\x00\x00\x00\x00\x01\x40\x00\x01\x80\x0e\x00\x01\x00\x62\x79\x74\x65\x6f\x72\x64\x65\x72\x00\x00\x00\x2c\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x08\x00\x02\x00\x00\x00\x00\x01\x08\x00\x03\x00\x00\x00\x00\x01\x08\x00\x04\x00\x00\x00\x00\x02\x08\x00\x05\x00\x00\x00\x00\x02\x3c\x00\x01\x80\x0b\x00\x01\x00\x65\x78\x74\x68\x64\x72\x00\x00\x2c\x00\x02\x80\x08\x00\x07\x00\x00\x00\x00\x01\x05\x00\x02\x00\x02\x00\x00\x00\x08\x00\x03\x00\x00\x00\x00\x02\x08\x00\x04\x00\x00\x00\x00\x02\x08\x00\x06\x00\x00\x00\x00\x01"), + // batch end + []byte("\x00\x00\x00\x0a"), + } + + c := &nftables.Conn{ + TestDial: func(req []netlink.Message) ([]netlink.Message, error) { + for idx, msg := range req { + b, err := msg.MarshalBinary() + if err != nil { + t.Fatal(err) + } + if len(b) < 16 { + continue + } + b = b[16:] + if len(want) == 0 { + t.Errorf("no want entry for message %d: %x", idx, b) + continue + } + if got, want := b, want[0]; !bytes.Equal(got, want) { + t.Errorf("message %d: %s", idx, linediff(nfdump(got), nfdump(want))) + } + want = want[1:] + } + return req, nil + }, + } + + c.FlushRuleset() + + filter := c.AddTable(&nftables.Table{ + Family: nftables.TableFamilyIPv4, + Name: "filter", + }) + + forward := c.AddChain(&nftables.Chain{ + Name: "forward", + Table: filter, + Type: nftables.ChainTypeFilter, + Hooknum: nftables.ChainHookForward, + Priority: nftables.ChainPriorityFilter, + }) + + c.AddRule(&nftables.Rule{ + Table: filter, + Chain: forward, + Exprs: []expr.Any{ + // [ meta load oifname => reg 1 ] + &expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1}, + // [ cmp eq reg 1 0x30707070 0x00000000 0x00000000 0x00000000 ] + &expr.Cmp{ + Op: expr.CmpOpEq, + Register: 1, + Data: ifname("uplink0"), + }, + + // [ meta load l4proto => reg 1 ] + &expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 1}, + // [ cmp eq reg 1 0x00000006 ] + &expr.Cmp{ + Op: expr.CmpOpEq, + Register: 1, + Data: []byte{unix.IPPROTO_TCP}, + }, + + // [ payload load 1b @ transport header + 13 => reg 1 ] + &expr.Payload{ + DestRegister: 1, + Base: expr.PayloadBaseTransportHeader, + Offset: 13, // TODO + Len: 1, // TODO + }, + // [ bitwise reg 1 = (reg=1 & 0x00000002 ) ^ 0x00000000 ] + &expr.Bitwise{ + DestRegister: 1, + SourceRegister: 1, + Len: 1, + Mask: []byte{0x02}, + Xor: []byte{0x00}, + }, + // [ cmp neq reg 1 0x00000000 ] + &expr.Cmp{ + Op: expr.CmpOpNeq, + Register: 1, + Data: []byte{0x00}, + }, + + // [ rt load tcpmss => reg 1 ] + &expr.Rt{ + Register: 1, + Key: expr.RtTCPMSS, + }, + // [ byteorder reg 1 = hton(reg 1, 2, 2) ] + &expr.Byteorder{ + DestRegister: 1, + SourceRegister: 1, + Op: expr.ByteorderHton, + Len: 2, + Size: 2, + }, + // [ exthdr write tcpopt reg 1 => 2b @ 2 + 2 ] + &expr.Exthdr{ + SourceRegister: 1, + Type: 2, // TODO + Offset: 2, + Len: 2, + Op: expr.ExthdrOpTcpopt, + }, + }, + }) + + if err := c.Flush(); err != nil { + t.Fatal(err) + } +}