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546 lines
14 KiB
Go
546 lines
14 KiB
Go
// +build linux
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package ipvs
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"net"
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"os/exec"
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"strings"
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"sync"
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"sync/atomic"
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"syscall"
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"unsafe"
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"github.com/Sirupsen/logrus"
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"github.com/vishvananda/netlink/nl"
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"github.com/vishvananda/netns"
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)
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// For Quick Reference IPVS related netlink message is described at the end of this file.
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var (
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native = nl.NativeEndian()
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ipvsFamily int
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ipvsOnce sync.Once
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)
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type genlMsgHdr struct {
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cmd uint8
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version uint8
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reserved uint16
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}
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type ipvsFlags struct {
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flags uint32
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mask uint32
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}
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func deserializeGenlMsg(b []byte) (hdr *genlMsgHdr) {
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return (*genlMsgHdr)(unsafe.Pointer(&b[0:unsafe.Sizeof(*hdr)][0]))
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}
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func (hdr *genlMsgHdr) Serialize() []byte {
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return (*(*[unsafe.Sizeof(*hdr)]byte)(unsafe.Pointer(hdr)))[:]
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}
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func (hdr *genlMsgHdr) Len() int {
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return int(unsafe.Sizeof(*hdr))
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}
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func (f *ipvsFlags) Serialize() []byte {
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return (*(*[unsafe.Sizeof(*f)]byte)(unsafe.Pointer(f)))[:]
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}
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func (f *ipvsFlags) Len() int {
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return int(unsafe.Sizeof(*f))
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}
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func setup() {
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ipvsOnce.Do(func() {
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var err error
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if out, err := exec.Command("modprobe", "-va", "ip_vs").CombinedOutput(); err != nil {
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logrus.Warnf("Running modprobe ip_vs failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
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}
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ipvsFamily, err = getIPVSFamily()
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if err != nil {
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logrus.Error("Could not get ipvs family information from the kernel. It is possible that ipvs is not enabled in your kernel. Native loadbalancing will not work until this is fixed.")
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}
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})
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}
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func fillService(s *Service) nl.NetlinkRequestData {
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cmdAttr := nl.NewRtAttr(ipvsCmdAttrService, nil)
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrAddressFamily, nl.Uint16Attr(s.AddressFamily))
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if s.FWMark != 0 {
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrFWMark, nl.Uint32Attr(s.FWMark))
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} else {
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrProtocol, nl.Uint16Attr(s.Protocol))
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrAddress, rawIPData(s.Address))
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// Port needs to be in network byte order.
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portBuf := new(bytes.Buffer)
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binary.Write(portBuf, binary.BigEndian, s.Port)
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrPort, portBuf.Bytes())
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}
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrSchedName, nl.ZeroTerminated(s.SchedName))
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if s.PEName != "" {
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrPEName, nl.ZeroTerminated(s.PEName))
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}
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f := &ipvsFlags{
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flags: s.Flags,
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mask: 0xFFFFFFFF,
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}
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrFlags, f.Serialize())
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrTimeout, nl.Uint32Attr(s.Timeout))
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nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrNetmask, nl.Uint32Attr(s.Netmask))
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return cmdAttr
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}
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func fillDestinaton(d *Destination) nl.NetlinkRequestData {
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cmdAttr := nl.NewRtAttr(ipvsCmdAttrDest, nil)
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nl.NewRtAttrChild(cmdAttr, ipvsDestAttrAddress, rawIPData(d.Address))
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// Port needs to be in network byte order.
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portBuf := new(bytes.Buffer)
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binary.Write(portBuf, binary.BigEndian, d.Port)
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nl.NewRtAttrChild(cmdAttr, ipvsDestAttrPort, portBuf.Bytes())
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nl.NewRtAttrChild(cmdAttr, ipvsDestAttrForwardingMethod, nl.Uint32Attr(d.ConnectionFlags&ConnectionFlagFwdMask))
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nl.NewRtAttrChild(cmdAttr, ipvsDestAttrWeight, nl.Uint32Attr(uint32(d.Weight)))
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nl.NewRtAttrChild(cmdAttr, ipvsDestAttrUpperThreshold, nl.Uint32Attr(d.UpperThreshold))
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nl.NewRtAttrChild(cmdAttr, ipvsDestAttrLowerThreshold, nl.Uint32Attr(d.LowerThreshold))
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return cmdAttr
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}
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func (i *Handle) doCmdwithResponse(s *Service, d *Destination, cmd uint8) ([][]byte, error) {
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req := newIPVSRequest(cmd)
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req.Seq = atomic.AddUint32(&i.seq, 1)
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if s == nil {
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req.Flags |= syscall.NLM_F_DUMP //Flag to dump all messages
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req.AddData(nl.NewRtAttr(ipvsCmdAttrService, nil)) //Add a dummy attribute
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} else {
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req.AddData(fillService(s))
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}
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if d == nil {
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if cmd == ipvsCmdGetDest {
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req.Flags |= syscall.NLM_F_DUMP
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}
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} else {
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req.AddData(fillDestinaton(d))
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}
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res, err := execute(i.sock, req, 0)
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if err != nil {
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return [][]byte{}, err
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}
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return res, nil
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}
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func (i *Handle) doCmd(s *Service, d *Destination, cmd uint8) error {
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_, err := i.doCmdwithResponse(s, d, cmd)
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return err
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}
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func getIPVSFamily() (int, error) {
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sock, err := nl.GetNetlinkSocketAt(netns.None(), netns.None(), syscall.NETLINK_GENERIC)
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if err != nil {
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return 0, err
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}
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defer sock.Close()
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req := newGenlRequest(genlCtrlID, genlCtrlCmdGetFamily)
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req.AddData(nl.NewRtAttr(genlCtrlAttrFamilyName, nl.ZeroTerminated("IPVS")))
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msgs, err := execute(sock, req, 0)
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if err != nil {
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return 0, err
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}
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for _, m := range msgs {
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hdr := deserializeGenlMsg(m)
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attrs, err := nl.ParseRouteAttr(m[hdr.Len():])
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if err != nil {
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return 0, err
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}
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for _, attr := range attrs {
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switch int(attr.Attr.Type) {
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case genlCtrlAttrFamilyID:
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return int(native.Uint16(attr.Value[0:2])), nil
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}
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}
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}
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return 0, fmt.Errorf("no family id in the netlink response")
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}
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func rawIPData(ip net.IP) []byte {
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family := nl.GetIPFamily(ip)
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if family == nl.FAMILY_V4 {
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return ip.To4()
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}
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return ip
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}
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func newIPVSRequest(cmd uint8) *nl.NetlinkRequest {
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return newGenlRequest(ipvsFamily, cmd)
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}
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func newGenlRequest(familyID int, cmd uint8) *nl.NetlinkRequest {
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req := nl.NewNetlinkRequest(familyID, syscall.NLM_F_ACK)
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req.AddData(&genlMsgHdr{cmd: cmd, version: 1})
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return req
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}
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func execute(s *nl.NetlinkSocket, req *nl.NetlinkRequest, resType uint16) ([][]byte, error) {
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var (
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err error
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)
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if err := s.Send(req); err != nil {
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return nil, err
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}
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pid, err := s.GetPid()
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if err != nil {
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return nil, err
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}
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var res [][]byte
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done:
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for {
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msgs, 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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for _, m := range msgs {
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if m.Header.Seq != req.Seq {
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continue
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}
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if m.Header.Pid != pid {
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return nil, fmt.Errorf("Wrong pid %d, expected %d", m.Header.Pid, pid)
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}
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if m.Header.Type == syscall.NLMSG_DONE {
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break done
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}
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if m.Header.Type == syscall.NLMSG_ERROR {
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error := int32(native.Uint32(m.Data[0:4]))
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if error == 0 {
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break done
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}
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return nil, syscall.Errno(-error)
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}
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if resType != 0 && m.Header.Type != resType {
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continue
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}
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res = append(res, m.Data)
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if m.Header.Flags&syscall.NLM_F_MULTI == 0 {
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break done
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}
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}
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}
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return res, nil
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}
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func parseIP(ip []byte, family uint16) (net.IP, error) {
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var resIP net.IP
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switch family {
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case syscall.AF_INET:
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resIP = (net.IP)(ip[:4])
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case syscall.AF_INET6:
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resIP = (net.IP)(ip[:16])
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default:
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return nil, fmt.Errorf("parseIP Error ip=%v", ip)
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}
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return resIP, nil
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}
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// parseStats
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func assembleStats(msg []byte) (SvcStats, error) {
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var s SvcStats
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attrs, err := nl.ParseRouteAttr(msg)
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if err != nil {
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return s, err
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}
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for _, attr := range attrs {
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attrType := int(attr.Attr.Type)
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switch attrType {
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case ipvsSvcStatsConns:
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s.Connections = native.Uint32(attr.Value)
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case ipvsSvcStatsPktsIn:
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s.PacketsIn = native.Uint32(attr.Value)
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case ipvsSvcStatsPktsOut:
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s.PacketsOut = native.Uint32(attr.Value)
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case ipvsSvcStatsBytesIn:
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s.BytesIn = native.Uint64(attr.Value)
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case ipvsSvcStatsBytesOut:
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s.BytesOut = native.Uint64(attr.Value)
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case ipvsSvcStatsCPS:
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s.CPS = native.Uint32(attr.Value)
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case ipvsSvcStatsPPSIn:
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s.PPSIn = native.Uint32(attr.Value)
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case ipvsSvcStatsPPSOut:
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s.PPSOut = native.Uint32(attr.Value)
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case ipvsSvcStatsBPSIn:
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s.BPSIn = native.Uint32(attr.Value)
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case ipvsSvcStatsBPSOut:
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s.BPSOut = native.Uint32(attr.Value)
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}
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}
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return s, nil
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}
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// assembleService assembles a services back from a hain of netlink attributes
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func assembleService(attrs []syscall.NetlinkRouteAttr) (*Service, error) {
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var s Service
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for _, attr := range attrs {
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attrType := int(attr.Attr.Type)
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switch attrType {
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case ipvsSvcAttrAddressFamily:
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s.AddressFamily = native.Uint16(attr.Value)
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case ipvsSvcAttrProtocol:
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s.Protocol = native.Uint16(attr.Value)
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case ipvsSvcAttrAddress:
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ip, err := parseIP(attr.Value, s.AddressFamily)
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if err != nil {
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return nil, err
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}
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s.Address = ip
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case ipvsSvcAttrPort:
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s.Port = binary.BigEndian.Uint16(attr.Value)
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case ipvsSvcAttrFWMark:
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s.FWMark = native.Uint32(attr.Value)
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case ipvsSvcAttrSchedName:
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s.SchedName = nl.BytesToString(attr.Value)
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case ipvsSvcAttrFlags:
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s.Flags = native.Uint32(attr.Value)
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case ipvsSvcAttrTimeout:
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s.Timeout = native.Uint32(attr.Value)
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case ipvsSvcAttrNetmask:
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s.Netmask = native.Uint32(attr.Value)
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case ipvsSvcAttrStats:
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stats, err := assembleStats(attr.Value)
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if err != nil {
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return nil, err
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}
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s.Stats = stats
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}
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}
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return &s, nil
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}
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// parseService given a ipvs netlink response this function will respond with a valid service entry, an error otherwise
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func (i *Handle) parseService(msg []byte) (*Service, error) {
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var s *Service
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//Remove General header for this message and parse the NetLink message
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hdr := deserializeGenlMsg(msg)
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NetLinkAttrs, err := nl.ParseRouteAttr(msg[hdr.Len():])
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if err != nil {
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return nil, err
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}
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if len(NetLinkAttrs) == 0 {
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return nil, fmt.Errorf("error no valid netlink message found while parsing service record")
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}
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//Now Parse and get IPVS related attributes messages packed in this message.
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ipvsAttrs, err := nl.ParseRouteAttr(NetLinkAttrs[0].Value)
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if err != nil {
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return nil, err
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}
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//Assemble all the IPVS related attribute messages and create a service record
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s, err = assembleService(ipvsAttrs)
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if err != nil {
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return nil, err
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}
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return s, nil
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}
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// doGetServicesCmd a wrapper which could be used commonly for both GetServices() and GetService(*Service)
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func (i *Handle) doGetServicesCmd(svc *Service) ([]*Service, error) {
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var res []*Service
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msgs, err := i.doCmdwithResponse(svc, nil, ipvsCmdGetService)
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if err != nil {
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return nil, err
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}
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for _, msg := range msgs {
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srv, err := i.parseService(msg)
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if err != nil {
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return nil, err
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}
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res = append(res, srv)
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}
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return res, nil
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}
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func assembleDestination(attrs []syscall.NetlinkRouteAttr) (*Destination, error) {
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var d Destination
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for _, attr := range attrs {
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attrType := int(attr.Attr.Type)
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switch attrType {
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case ipvsDestAttrAddress:
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ip, err := parseIP(attr.Value, syscall.AF_INET)
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if err != nil {
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return nil, err
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}
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d.Address = ip
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case ipvsDestAttrPort:
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d.Port = binary.BigEndian.Uint16(attr.Value)
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case ipvsDestAttrForwardingMethod:
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d.ConnectionFlags = native.Uint32(attr.Value)
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case ipvsDestAttrWeight:
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d.Weight = int(native.Uint16(attr.Value))
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case ipvsDestAttrUpperThreshold:
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d.UpperThreshold = native.Uint32(attr.Value)
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case ipvsDestAttrLowerThreshold:
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d.LowerThreshold = native.Uint32(attr.Value)
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case ipvsDestAttrAddressFamily:
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d.AddressFamily = native.Uint16(attr.Value)
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}
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}
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return &d, nil
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}
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// parseDestination given a ipvs netlink response this function will respond with a valid destination entry, an error otherwise
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func (i *Handle) parseDestination(msg []byte) (*Destination, error) {
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var dst *Destination
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//Remove General header for this message
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hdr := deserializeGenlMsg(msg)
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NetLinkAttrs, err := nl.ParseRouteAttr(msg[hdr.Len():])
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if err != nil {
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return nil, err
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}
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if len(NetLinkAttrs) == 0 {
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return nil, fmt.Errorf("error no valid netlink message found while parsing destination record")
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}
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//Now Parse and get IPVS related attributes messages packed in this message.
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ipvsAttrs, err := nl.ParseRouteAttr(NetLinkAttrs[0].Value)
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if err != nil {
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return nil, err
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}
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//Assemble netlink attributes and create a Destination record
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dst, err = assembleDestination(ipvsAttrs)
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if err != nil {
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return nil, err
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}
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return dst, nil
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}
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// doGetDestinationsCmd a wrapper function to be used by GetDestinations and GetDestination(d) apis
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func (i *Handle) doGetDestinationsCmd(s *Service, d *Destination) ([]*Destination, error) {
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var res []*Destination
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msgs, err := i.doCmdwithResponse(s, d, ipvsCmdGetDest)
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if err != nil {
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return nil, err
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}
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for _, msg := range msgs {
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dest, err := i.parseDestination(msg)
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if err != nil {
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return res, err
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}
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res = append(res, dest)
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}
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return res, nil
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}
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// IPVS related netlink message format explained
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/* EACH NETLINK MSG is of the below format, this is what we will receive from execute() api.
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If we have multiple netlink objects to process like GetServices() etc., execute() will
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supply an array of this below object
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NETLINK MSG
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|-----------------------------------|
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0 1 2 3
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|--------|--------|--------|--------| -
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| CMD ID | VER | RESERVED | |==> General Message Header represented by genlMsgHdr
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|-----------------------------------| -
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| ATTR LEN | ATTR TYPE | |
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|-----------------------------------| |
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| | |
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| VALUE | |
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| []byte Array of IPVS MSG | |==> Attribute Message represented by syscall.NetlinkRouteAttr
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| PADDED BY 4 BYTES | |
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| | |
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|-----------------------------------| -
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Once We strip genlMsgHdr from above NETLINK MSG, we should parse the VALUE.
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VALUE will have an array of netlink attributes (syscall.NetlinkRouteAttr) such that each attribute will
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represent a "Service" or "Destination" object's field. If we assemble these attributes we can construct
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Service or Destination.
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IPVS MSG
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|-----------------------------------|
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0 1 2 3
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|--------|--------|--------|--------|
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| ATTR LEN | ATTR TYPE |
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|-----------------------------------|
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| []byte IPVS ATTRIBUTE BY 4 BYTES |
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|-----------------------------------|
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NEXT ATTRIBUTE
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|-----------------------------------|
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| ATTR LEN | ATTR TYPE |
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|-----------------------------------|
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| []byte IPVS ATTRIBUTE BY 4 BYTES |
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NEXT ATTRIBUTE
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| []byte IPVS ATTRIBUTE BY 4 BYTES |
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*/
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