Add dup expr support (#81)

This commit is contained in:
Alexis PIRES 2019-12-13 23:35:06 +01:00 committed by Michael Stapelberg
parent fc92ae7899
commit e2e83d0ff5
2 changed files with 255 additions and 0 deletions

67
expr/dup.go Normal file
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@ -0,0 +1,67 @@
// 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"
"github.com/google/nftables/binaryutil"
"github.com/mdlayher/netlink"
"golang.org/x/sys/unix"
)
type Dup struct {
RegAddr uint32
RegDev uint32
IsRegDevSet bool
}
func (e *Dup) marshal() ([]byte, error) {
attrs := []netlink.Attribute{
{Type: unix.NFTA_DUP_SREG_ADDR, Data: binaryutil.BigEndian.PutUint32(e.RegAddr)},
}
if e.IsRegDevSet {
attrs = append(attrs, netlink.Attribute{Type: unix.NFTA_DUP_SREG_DEV, Data: binaryutil.BigEndian.PutUint32(e.RegDev)})
}
data, err := netlink.MarshalAttributes(attrs)
if err != nil {
return nil, err
}
return netlink.MarshalAttributes([]netlink.Attribute{
{Type: unix.NFTA_EXPR_NAME, Data: []byte("dup\x00")},
{Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: data},
})
}
func (e *Dup) 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_DUP_SREG_ADDR:
e.RegAddr = ad.Uint32()
case unix.NFTA_DUP_SREG_DEV:
e.RegDev = ad.Uint32()
}
}
return ad.Err()
}

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@ -3629,3 +3629,191 @@ func TestJHash(t *testing.T) {
t.Fatal(err)
}
}
func TestDup(t *testing.T) {
// The want byte sequences come from stracing nft(8), e.g.:
// strace -f -v -x -s 2048 -eraw=sendto nft add rule filter prerouting mark set jhash ip saddr mod 2
//
// The nft(8) command sequence was taken from:
// https://wiki.nftables.org/wiki-nftables/index.php/Quick_reference-nftables_in_10_minutes#Tcp
want := [][]byte{
// batch begin
[]byte("\x00\x00\x00\x0a"),
// nft flush ruleset
[]byte("\x00\x00\x00\x00"),
// nft add table ip mangle
[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x6d\x61\x6e\x67\x6c\x65\x00\x00\x08\x00\x02\x00\x00\x00\x00\x00"),
// nft add chain ip mangle base-chain { type filter hook prerouting priority 0 \; }
[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x6d\x61\x6e\x67\x6c\x65\x00\x00\x0f\x00\x03\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00\x14\x00\x04\x80\x08\x00\x01\x00\x00\x00\x00\x00\x08\x00\x02\x00\x00\x00\x00\x00\x0b\x00\x07\x00\x66\x69\x6c\x74\x65\x72\x00\x00"),
// nft add rule mangle base-chain dup to 127.0.0.50 device lo
[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x6d\x61\x6e\x67\x6c\x65\x00\x00\x0f\x00\x02\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00\x7c\x00\x04\x80\x2c\x00\x01\x80\x0e\x00\x01\x00\x69\x6d\x6d\x65\x64\x69\x61\x74\x65\x00\x00\x00\x18\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x0c\x00\x02\x80\x08\x00\x01\x00\x7f\x00\x00\x32\x2c\x00\x01\x80\x0e\x00\x01\x00\x69\x6d\x6d\x65\x64\x69\x61\x74\x65\x00\x00\x00\x18\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x02\x0c\x00\x02\x80\x08\x00\x01\x00\x01\x00\x00\x00\x20\x00\x01\x80\x08\x00\x01\x00\x64\x75\x70\x00\x14\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x08\x00\x02\x00\x00\x00\x00\x02"),
// 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()
mangle := c.AddTable(&nftables.Table{
Family: nftables.TableFamilyIPv4,
Name: "mangle",
})
prerouting := c.AddChain(&nftables.Chain{
Name: "base-chain",
Table: mangle,
Type: nftables.ChainTypeFilter,
Hooknum: nftables.ChainHookPrerouting,
Priority: nftables.ChainPriorityFilter,
})
lo, err := net.InterfaceByName("lo")
if err != nil {
t.Fatal(err)
}
c.AddRule(&nftables.Rule{
Table: mangle,
Chain: prerouting,
Exprs: []expr.Any{
// [ immediate reg 1 0x3200007f ]
&expr.Immediate{
Register: 1,
Data: net.ParseIP("127.0.0.50").To4(),
},
// [ immediate reg 2 0x00000001 ]
&expr.Immediate{
Register: 2,
Data: binaryutil.NativeEndian.PutUint32(uint32(lo.Index)),
},
// [ dup sreg_addr 1 sreg_dev 2 ]
&expr.Dup{
RegAddr: 1,
RegDev: 2,
IsRegDevSet: true,
},
},
})
if err := c.Flush(); err != nil {
t.Fatal(err)
}
}
func TestDupWoDev(t *testing.T) {
// The want byte sequences come from stracing nft(8), e.g.:
// strace -f -v -x -s 2048 -eraw=sendto nft add rule filter prerouting mark set jhash ip saddr mod 2
//
// The nft(8) command sequence was taken from:
// https://wiki.nftables.org/wiki-nftables/index.php/Quick_reference-nftables_in_10_minutes#Tcp
want := [][]byte{
// batch begin
[]byte("\x00\x00\x00\x0a"),
// nft flush ruleset
[]byte("\x00\x00\x00\x00"),
// nft add table ip mangle
[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x6d\x61\x6e\x67\x6c\x65\x00\x00\x08\x00\x02\x00\x00\x00\x00\x00"),
// nft add chain ip mangle base-chain { type filter hook prerouting priority 0 \; }
[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x6d\x61\x6e\x67\x6c\x65\x00\x00\x0f\x00\x03\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00\x14\x00\x04\x80\x08\x00\x01\x00\x00\x00\x00\x00\x08\x00\x02\x00\x00\x00\x00\x00\x0b\x00\x07\x00\x66\x69\x6c\x74\x65\x72\x00\x00"),
// nft add rule mangle base-chain dup to 127.0.0.50
[]byte("\x02\x00\x00\x00\x0b\x00\x01\x00\x6d\x61\x6e\x67\x6c\x65\x00\x00\x0f\x00\x02\x00\x62\x61\x73\x65\x2d\x63\x68\x61\x69\x6e\x00\x00\x48\x00\x04\x80\x2c\x00\x01\x80\x0e\x00\x01\x00\x69\x6d\x6d\x65\x64\x69\x61\x74\x65\x00\x00\x00\x18\x00\x02\x80\x08\x00\x01\x00\x00\x00\x00\x01\x0c\x00\x02\x80\x08\x00\x01\x00\x7f\x00\x00\x32\x18\x00\x01\x80\x08\x00\x01\x00\x64\x75\x70\x00\x0c\x00\x02\x80\x08\x00\x01\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()
mangle := c.AddTable(&nftables.Table{
Family: nftables.TableFamilyIPv4,
Name: "mangle",
})
prerouting := c.AddChain(&nftables.Chain{
Name: "base-chain",
Table: mangle,
Type: nftables.ChainTypeFilter,
Hooknum: nftables.ChainHookPrerouting,
Priority: nftables.ChainPriorityFilter,
})
c.AddRule(&nftables.Rule{
Table: mangle,
Chain: prerouting,
Exprs: []expr.Any{
// [ immediate reg 1 0x3200007f ]
&expr.Immediate{
Register: 1,
Data: net.ParseIP("127.0.0.50").To4(),
},
// [ dup sreg_addr 1 sreg_dev 2 ]
&expr.Dup{
RegAddr: 1,
IsRegDevSet: false,
},
},
})
if err := c.Flush(); err != nil {
t.Fatal(err)
}
}