mirror of https://github.com/vishvananda/netlink
262 lines
6.1 KiB
Go
262 lines
6.1 KiB
Go
package netlink
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import (
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"errors"
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"fmt"
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"net"
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"syscall"
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"github.com/vishvananda/netlink/nl"
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"golang.org/x/sys/unix"
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)
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const (
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sizeofSocketID = 0x30
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sizeofSocketRequest = sizeofSocketID + 0x8
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sizeofSocket = sizeofSocketID + 0x18
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)
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type socketRequest struct {
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Family uint8
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Protocol uint8
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Ext uint8
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pad uint8
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States uint32
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ID SocketID
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}
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type writeBuffer struct {
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Bytes []byte
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pos int
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}
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func (b *writeBuffer) Write(c byte) {
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b.Bytes[b.pos] = c
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b.pos++
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}
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func (b *writeBuffer) Next(n int) []byte {
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s := b.Bytes[b.pos : b.pos+n]
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b.pos += n
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return s
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}
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func (r *socketRequest) Serialize() []byte {
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b := writeBuffer{Bytes: make([]byte, sizeofSocketRequest)}
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b.Write(r.Family)
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b.Write(r.Protocol)
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b.Write(r.Ext)
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b.Write(r.pad)
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native.PutUint32(b.Next(4), r.States)
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networkOrder.PutUint16(b.Next(2), r.ID.SourcePort)
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networkOrder.PutUint16(b.Next(2), r.ID.DestinationPort)
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if r.Family == unix.AF_INET6 {
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copy(b.Next(16), r.ID.Source)
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copy(b.Next(16), r.ID.Destination)
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} else {
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copy(b.Next(4), r.ID.Source.To4())
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b.Next(12)
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copy(b.Next(4), r.ID.Destination.To4())
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b.Next(12)
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}
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native.PutUint32(b.Next(4), r.ID.Interface)
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native.PutUint32(b.Next(4), r.ID.Cookie[0])
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native.PutUint32(b.Next(4), r.ID.Cookie[1])
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return b.Bytes
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}
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func (r *socketRequest) Len() int { return sizeofSocketRequest }
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type readBuffer struct {
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Bytes []byte
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pos int
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}
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func (b *readBuffer) Read() byte {
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c := b.Bytes[b.pos]
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b.pos++
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return c
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}
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func (b *readBuffer) Next(n int) []byte {
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s := b.Bytes[b.pos : b.pos+n]
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b.pos += n
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return s
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}
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func (s *Socket) deserialize(b []byte) error {
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if len(b) < sizeofSocket {
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return fmt.Errorf("socket data short read (%d); want %d", len(b), sizeofSocket)
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}
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rb := readBuffer{Bytes: b}
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s.Family = rb.Read()
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s.State = rb.Read()
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s.Timer = rb.Read()
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s.Retrans = rb.Read()
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s.ID.SourcePort = networkOrder.Uint16(rb.Next(2))
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s.ID.DestinationPort = networkOrder.Uint16(rb.Next(2))
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if s.Family == unix.AF_INET6 {
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s.ID.Source = net.IP(rb.Next(16))
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s.ID.Destination = net.IP(rb.Next(16))
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} else {
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s.ID.Source = net.IPv4(rb.Read(), rb.Read(), rb.Read(), rb.Read())
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rb.Next(12)
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s.ID.Destination = net.IPv4(rb.Read(), rb.Read(), rb.Read(), rb.Read())
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rb.Next(12)
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}
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s.ID.Interface = native.Uint32(rb.Next(4))
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s.ID.Cookie[0] = native.Uint32(rb.Next(4))
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s.ID.Cookie[1] = native.Uint32(rb.Next(4))
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s.Expires = native.Uint32(rb.Next(4))
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s.RQueue = native.Uint32(rb.Next(4))
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s.WQueue = native.Uint32(rb.Next(4))
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s.UID = native.Uint32(rb.Next(4))
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s.INode = native.Uint32(rb.Next(4))
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return nil
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}
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// SocketGet returns the Socket identified by its local and remote addresses.
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func SocketGet(local, remote net.Addr) (*Socket, error) {
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localTCP, ok := local.(*net.TCPAddr)
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if !ok {
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return nil, ErrNotImplemented
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}
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remoteTCP, ok := remote.(*net.TCPAddr)
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if !ok {
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return nil, ErrNotImplemented
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}
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localIP := localTCP.IP.To4()
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if localIP == nil {
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return nil, ErrNotImplemented
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}
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remoteIP := remoteTCP.IP.To4()
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if remoteIP == nil {
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return nil, ErrNotImplemented
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}
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s, err := nl.Subscribe(unix.NETLINK_INET_DIAG)
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if err != nil {
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return nil, err
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}
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defer s.Close()
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req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, 0)
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req.AddData(&socketRequest{
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Family: unix.AF_INET,
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Protocol: unix.IPPROTO_TCP,
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ID: SocketID{
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SourcePort: uint16(localTCP.Port),
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DestinationPort: uint16(remoteTCP.Port),
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Source: localIP,
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Destination: remoteIP,
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Cookie: [2]uint32{nl.TCPDIAG_NOCOOKIE, nl.TCPDIAG_NOCOOKIE},
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},
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})
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s.Send(req)
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msgs, from, err := s.Receive()
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if err != nil {
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return nil, err
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}
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if from.Pid != nl.PidKernel {
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return nil, fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel)
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}
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if len(msgs) == 0 {
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return nil, errors.New("no message nor error from netlink")
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}
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if len(msgs) > 2 {
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return nil, fmt.Errorf("multiple (%d) matching sockets", len(msgs))
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}
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sock := &Socket{}
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if err := sock.deserialize(msgs[0].Data); err != nil {
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return nil, err
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}
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return sock, nil
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}
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// SocketDiagTCPInfo requests INET_DIAG_INFO for TCP protocol for specified family type.
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func SocketDiagTCPInfo(family uint8) ([]*InetDiagTCPInfoResp, error) {
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s, err := nl.Subscribe(unix.NETLINK_INET_DIAG)
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if err != nil {
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return nil, err
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}
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defer s.Close()
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req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
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req.AddData(&socketRequest{
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Family: family,
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Protocol: unix.IPPROTO_TCP,
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Ext: (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
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States: uint32(0xfff), // All TCP states
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})
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s.Send(req)
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var result []*InetDiagTCPInfoResp
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loop:
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for {
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msgs, from, err := s.Receive()
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if err != nil {
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return nil, err
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}
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if from.Pid != nl.PidKernel {
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return nil, fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel)
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}
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if len(msgs) == 0 {
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return nil, errors.New("no message nor error from netlink")
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}
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for _, m := range msgs {
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switch m.Header.Type {
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case unix.NLMSG_DONE:
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break loop
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case unix.NLMSG_ERROR:
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native := nl.NativeEndian()
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error := int32(native.Uint32(m.Data[0:4]))
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return nil, syscall.Errno(-error)
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}
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sockInfo := &Socket{}
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if err := sockInfo.deserialize(m.Data); err != nil {
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return nil, err
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}
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attrs, err := nl.ParseRouteAttr(m.Data[sizeofSocket:])
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if err != nil {
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return nil, err
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}
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res, err := attrsToInetDiagTCPInfoResp(attrs, sockInfo)
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if err != nil {
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return nil, err
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}
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result = append(result, res)
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}
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}
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return result, nil
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}
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func attrsToInetDiagTCPInfoResp(attrs []syscall.NetlinkRouteAttr, sockInfo *Socket) (*InetDiagTCPInfoResp, error) {
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var tcpInfo *TCPInfo
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var tcpBBRInfo *TCPBBRInfo
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for _, a := range attrs {
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if a.Attr.Type == INET_DIAG_INFO {
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tcpInfo = &TCPInfo{}
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if err := tcpInfo.deserialize(a.Value); err != nil {
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return nil, err
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}
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continue
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}
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if a.Attr.Type == INET_DIAG_BBRINFO {
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tcpBBRInfo = &TCPBBRInfo{}
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if err := tcpBBRInfo.deserialize(a.Value); err != nil {
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return nil, err
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}
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continue
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}
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}
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return &InetDiagTCPInfoResp{
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InetDiagMsg: sockInfo,
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TCPInfo: tcpInfo,
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TCPBBRInfo: tcpBBRInfo,
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}, nil
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}
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