From 9dee1969253b7ef581b42f55ac180aaf924cf41c Mon Sep 17 00:00:00 2001 From: Serguei Bezverkhi Date: Thu, 28 Nov 2019 03:43:38 -0500 Subject: [PATCH] Add expression and tests for numgen (#77) Signed-off-by: Serguei Bezverkhi --- expr/numgen.go | 78 +++++++++++++++++++++++++++++++++++ nftables_test.go | 104 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 182 insertions(+) create mode 100644 expr/numgen.go diff --git a/expr/numgen.go b/expr/numgen.go new file mode 100644 index 0000000..8c51545 --- /dev/null +++ b/expr/numgen.go @@ -0,0 +1,78 @@ +// 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 ( + "encoding/binary" + "fmt" + + "github.com/google/nftables/binaryutil" + "github.com/mdlayher/netlink" + "golang.org/x/sys/unix" +) + +// Numgen defines Numgen expression structure +type Numgen struct { + Register uint32 + Modulus uint32 + Type uint32 + Offset uint32 +} + +func (e *Numgen) marshal() ([]byte, error) { + // Currently only two types are supported, failing if Type is not of two known types + switch e.Type { + case unix.NFT_NG_INCREMENTAL: + case unix.NFT_NG_RANDOM: + default: + return nil, fmt.Errorf("unsupported numgen type %d", e.Type) + } + + data, err := netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_NG_DREG, Data: binaryutil.BigEndian.PutUint32(e.Register)}, + {Type: unix.NFTA_NG_MODULUS, Data: binaryutil.BigEndian.PutUint32(e.Modulus)}, + {Type: unix.NFTA_NG_TYPE, Data: binaryutil.BigEndian.PutUint32(e.Type)}, + {Type: unix.NFTA_NG_OFFSET, Data: binaryutil.BigEndian.PutUint32(e.Offset)}, + }) + if err != nil { + return nil, err + } + + return netlink.MarshalAttributes([]netlink.Attribute{ + {Type: unix.NFTA_EXPR_NAME, Data: []byte("numgen\x00")}, + {Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data}, + }) +} + +func (e *Numgen) unmarshal(data []byte) error { + ad, err := netlink.NewAttributeDecoder(data) + if err != nil { + return err + } + ad.ByteOrder = binary.BigEndian + for ad.Next() { + switch ad.Type() { + case unix.NFTA_NG_DREG: + e.Register = ad.Uint32() + case unix.NFTA_NG_MODULUS: + e.Modulus = ad.Uint32() + case unix.NFTA_NG_TYPE: + e.Type = ad.Uint32() + case unix.NFTA_NG_OFFSET: + e.Offset = ad.Uint32() + } + } + return ad.Err() +} diff --git a/nftables_test.go b/nftables_test.go index 0fd22ab..7c94e48 100644 --- a/nftables_test.go +++ b/nftables_test.go @@ -3231,6 +3231,110 @@ func TestFib(t *testing.T) { } } +func TestNumgen(t *testing.T) { + tests := []struct { + name string + chain *nftables.Chain + want [][]byte + numgenExprs []expr.Any + }{ + { + name: "numgen random", + chain: &nftables.Chain{ + Name: "base-chain", + }, + want: [][]byte{ + // batch begin + []byte("\x00\x00\x00\x0a"), + // 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 ip filter base-chain + []byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x0f\x00\x03\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00"), + // nft add rule ip filter base-chain numgen random mod 1 offset 0 vmap { 0 : drop } + []byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x0f\x00\x02\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00\x38\x00\x04\x80\x34\x00\x01\x80\x0b\x00\x01\x00\x6e\x75\x6d\x67\x65\x6e\x00\x00\x24\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\x00"), + // batch end + []byte("\x00\x00\x00\x0a"), + }, + numgenExprs: []expr.Any{ + &expr.Numgen{ + Register: 1, + Type: unix.NFT_NG_RANDOM, + Modulus: 0x1, + Offset: 0, + }, + }, + }, + { + name: "numgen incremental", + chain: &nftables.Chain{ + Name: "base-chain", + }, + want: [][]byte{ + // batch begin + []byte("\x00\x00\x00\x0a"), + // 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 ip filter base-chain + []byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x0f\x00\x03\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00"), + // nft add rule ip filter base-chain numgen inc mod 1 offset 0 vmap { 0 : drop } + []byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x66\x69\x6c\x74\x65\x72\x00\x00\x0f\x00\x02\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00\x38\x00\x04\x80\x34\x00\x01\x80\x0b\x00\x01\x00\x6e\x75\x6d\x67\x65\x6e\x00\x00\x24\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\x00\x08\x00\x04\x00\x00\x00\x00\x00"), + // batch end + []byte("\x00\x00\x00\x0a"), + }, + numgenExprs: []expr.Any{ + &expr.Numgen{ + Register: 1, + Type: unix.NFT_NG_INCREMENTAL, + Modulus: 0x1, + Offset: 0, + }, + }, + }, + } + + for _, tt := range tests { + 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(tt.want[idx]) == 0 { + t.Errorf("no want entry for message %d: %x", idx, b) + continue + } + got := b + if !bytes.Equal(got, tt.want[idx]) { + t.Errorf("message %d: %s", idx, linediff(nfdump(got), nfdump(tt.want[idx]))) + } + } + return req, nil + }, + } + + filter := c.AddTable(&nftables.Table{ + Family: nftables.TableFamilyIPv4, + Name: "filter", + }) + + tt.chain.Table = filter + chain := c.AddChain(tt.chain) + c.AddRule(&nftables.Rule{ + Table: filter, + Chain: chain, + Exprs: tt.numgenExprs, + }) + if err := c.Flush(); err != nil { + t.Fatalf("Test \"%s\" failed with error: %+v", tt.name, err) + } + } +} + func TestMap(t *testing.T) { tests := []struct { name string