Revert vendor directory to support old golang (GOPATH mode)

gomodule is still in progress to migrate for now, hence multus
team decide to keep vendor directory to support build without
gomodule.

vendor/github.com/vishvananda/netlink/socket_linux.go

@@ -0,0 +1,159 @@
+package netlink
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"syscall"
+
+	"github.com/vishvananda/netlink/nl"
+)
+
+const (
+	sizeofSocketID      = 0x30
+	sizeofSocketRequest = sizeofSocketID + 0x8
+	sizeofSocket        = sizeofSocketID + 0x18
+)
+
+type socketRequest struct {
+	Family   uint8
+	Protocol uint8
+	Ext      uint8
+	pad      uint8
+	States   uint32
+	ID       SocketID
+}
+
+type writeBuffer struct {
+	Bytes []byte
+	pos   int
+}
+
+func (b *writeBuffer) Write(c byte) {
+	b.Bytes[b.pos] = c
+	b.pos++
+}
+
+func (b *writeBuffer) Next(n int) []byte {
+	s := b.Bytes[b.pos : b.pos+n]
+	b.pos += n
+	return s
+}
+
+func (r *socketRequest) Serialize() []byte {
+	b := writeBuffer{Bytes: make([]byte, sizeofSocketRequest)}
+	b.Write(r.Family)
+	b.Write(r.Protocol)
+	b.Write(r.Ext)
+	b.Write(r.pad)
+	native.PutUint32(b.Next(4), r.States)
+	networkOrder.PutUint16(b.Next(2), r.ID.SourcePort)
+	networkOrder.PutUint16(b.Next(2), r.ID.DestinationPort)
+	copy(b.Next(4), r.ID.Source.To4())
+	b.Next(12)
+	copy(b.Next(4), r.ID.Destination.To4())
+	b.Next(12)
+	native.PutUint32(b.Next(4), r.ID.Interface)
+	native.PutUint32(b.Next(4), r.ID.Cookie[0])
+	native.PutUint32(b.Next(4), r.ID.Cookie[1])
+	return b.Bytes
+}
+
+func (r *socketRequest) Len() int { return sizeofSocketRequest }
+
+type readBuffer struct {
+	Bytes []byte
+	pos   int
+}
+
+func (b *readBuffer) Read() byte {
+	c := b.Bytes[b.pos]
+	b.pos++
+	return c
+}
+
+func (b *readBuffer) Next(n int) []byte {
+	s := b.Bytes[b.pos : b.pos+n]
+	b.pos += n
+	return s
+}
+
+func (s *Socket) deserialize(b []byte) error {
+	if len(b) < sizeofSocket {
+		return fmt.Errorf("socket data short read (%d); want %d", len(b), sizeofSocket)
+	}
+	rb := readBuffer{Bytes: b}
+	s.Family = rb.Read()
+	s.State = rb.Read()
+	s.Timer = rb.Read()
+	s.Retrans = rb.Read()
+	s.ID.SourcePort = networkOrder.Uint16(rb.Next(2))
+	s.ID.DestinationPort = networkOrder.Uint16(rb.Next(2))
+	s.ID.Source = net.IPv4(rb.Read(), rb.Read(), rb.Read(), rb.Read())
+	rb.Next(12)
+	s.ID.Destination = net.IPv4(rb.Read(), rb.Read(), rb.Read(), rb.Read())
+	rb.Next(12)
+	s.ID.Interface = native.Uint32(rb.Next(4))
+	s.ID.Cookie[0] = native.Uint32(rb.Next(4))
+	s.ID.Cookie[1] = native.Uint32(rb.Next(4))
+	s.Expires = native.Uint32(rb.Next(4))
+	s.RQueue = native.Uint32(rb.Next(4))
+	s.WQueue = native.Uint32(rb.Next(4))
+	s.UID = native.Uint32(rb.Next(4))
+	s.INode = native.Uint32(rb.Next(4))
+	return nil
+}
+
+// SocketGet returns the Socket identified by its local and remote addresses.
+func SocketGet(local, remote net.Addr) (*Socket, error) {
+	localTCP, ok := local.(*net.TCPAddr)
+	if !ok {
+		return nil, ErrNotImplemented
+	}
+	remoteTCP, ok := remote.(*net.TCPAddr)
+	if !ok {
+		return nil, ErrNotImplemented
+	}
+	localIP := localTCP.IP.To4()
+	if localIP == nil {
+		return nil, ErrNotImplemented
+	}
+	remoteIP := remoteTCP.IP.To4()
+	if remoteIP == nil {
+		return nil, ErrNotImplemented
+	}
+
+	s, err := nl.Subscribe(syscall.NETLINK_INET_DIAG)
+	if err != nil {
+		return nil, err
+	}
+	defer s.Close()
+	req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, 0)
+	req.AddData(&socketRequest{
+		Family:   syscall.AF_INET,
+		Protocol: syscall.IPPROTO_TCP,
+		ID: SocketID{
+			SourcePort:      uint16(localTCP.Port),
+			DestinationPort: uint16(remoteTCP.Port),
+			Source:          localIP,
+			Destination:     remoteIP,
+			Cookie:          [2]uint32{nl.TCPDIAG_NOCOOKIE, nl.TCPDIAG_NOCOOKIE},
+		},
+	})
+	s.Send(req)
+	msgs, err := s.Receive()
+	if err != nil {
+		return nil, err
+	}
+	if len(msgs) == 0 {
+		return nil, errors.New("no message nor error from netlink")
+	}
+	if len(msgs) > 2 {
+		return nil, fmt.Errorf("multiple (%d) matching sockets", len(msgs))
+	}
+	sock := &Socket{}
+	if err := sock.deserialize(msgs[0].Data); err != nil {
+		return nil, err
+	}
+	return sock, nil
+}