93 lines
2.6 KiB
Go
93 lines
2.6 KiB
Go
// Copyright 2023 Google LLC. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package expr
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import (
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"encoding/binary"
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"golang.org/x/sys/unix"
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"github.com/google/nftables/binaryutil"
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"github.com/mdlayher/netlink"
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)
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type Socket struct {
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Key SocketKey
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Level uint32
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Register uint32
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}
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type SocketKey uint32
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const (
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// TODO, Once the constants below are available in golang.org/x/sys/unix, switch to use those.
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NFTA_SOCKET_KEY = 1
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NFTA_SOCKET_DREG = 2
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NFTA_SOCKET_LEVEL = 3
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NFT_SOCKET_TRANSPARENT = 0
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NFT_SOCKET_MARK = 1
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NFT_SOCKET_WILDCARD = 2
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NFT_SOCKET_CGROUPV2 = 3
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SocketKeyTransparent SocketKey = NFT_SOCKET_TRANSPARENT
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SocketKeyMark SocketKey = NFT_SOCKET_MARK
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SocketKeyWildcard SocketKey = NFT_SOCKET_WILDCARD
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SocketKeyCgroupv2 SocketKey = NFT_SOCKET_CGROUPV2
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)
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func (e *Socket) marshal(fam byte) ([]byte, error) {
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exprData, err := e.marshalData(fam)
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if err != nil {
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return nil, err
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}
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return netlink.MarshalAttributes([]netlink.Attribute{
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{Type: unix.NFTA_EXPR_NAME, Data: []byte("socket\x00")},
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{Type: unix.NLA_F_NESTED | unix.NFTA_EXPR_DATA, Data: exprData},
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})
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}
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func (e *Socket) marshalData(fam byte) ([]byte, error) {
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// NOTE: Socket.Level is only used when Socket.Key == SocketKeyCgroupv2. But `nft` always encoding it. Check link below:
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// http://git.netfilter.org/nftables/tree/src/netlink_linearize.c?id=0583bac241ea18c9d7f61cb20ca04faa1e043b78#n319
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return netlink.MarshalAttributes(
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[]netlink.Attribute{
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{Type: NFTA_SOCKET_DREG, Data: binaryutil.BigEndian.PutUint32(e.Register)},
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{Type: NFTA_SOCKET_KEY, Data: binaryutil.BigEndian.PutUint32(uint32(e.Key))},
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{Type: NFTA_SOCKET_LEVEL, Data: binaryutil.BigEndian.PutUint32(uint32(e.Level))},
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},
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)
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}
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func (e *Socket) unmarshal(fam byte, data []byte) error {
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ad, err := netlink.NewAttributeDecoder(data)
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if err != nil {
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return err
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}
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ad.ByteOrder = binary.BigEndian
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for ad.Next() {
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switch ad.Type() {
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case NFTA_SOCKET_DREG:
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e.Register = ad.Uint32()
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case NFTA_SOCKET_KEY:
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e.Key = SocketKey(ad.Uint32())
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case NFTA_SOCKET_LEVEL:
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e.Level = ad.Uint32()
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}
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}
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return ad.Err()
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}
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