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moby--moby/libnetwork/ipvs/netlink.go
Jana Radhakrishnan 1dbff60121 Do not panic if failed to get ipvs family
Instead log a descriptive error message.

Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>
2016-06-10 08:33:19 -07:00

234 lines
5.6 KiB
Go

// +build linux
package ipvs
import (
"bytes"
"encoding/binary"
"fmt"
"net"
"os/exec"
"strings"
"sync"
"syscall"
"unsafe"
"github.com/Sirupsen/logrus"
"github.com/vishvananda/netlink/nl"
"github.com/vishvananda/netns"
)
var (
native = nl.NativeEndian()
ipvsFamily int
ipvsOnce sync.Once
)
type genlMsgHdr struct {
cmd uint8
version uint8
reserved uint16
}
type ipvsFlags struct {
flags uint32
mask uint32
}
func deserializeGenlMsg(b []byte) (hdr *genlMsgHdr) {
return (*genlMsgHdr)(unsafe.Pointer(&b[0:unsafe.Sizeof(*hdr)][0]))
}
func (hdr *genlMsgHdr) Serialize() []byte {
return (*(*[unsafe.Sizeof(*hdr)]byte)(unsafe.Pointer(hdr)))[:]
}
func (hdr *genlMsgHdr) Len() int {
return int(unsafe.Sizeof(*hdr))
}
func (f *ipvsFlags) Serialize() []byte {
return (*(*[unsafe.Sizeof(*f)]byte)(unsafe.Pointer(f)))[:]
}
func (f *ipvsFlags) Len() int {
return int(unsafe.Sizeof(*f))
}
func setup() {
ipvsOnce.Do(func() {
var err error
if out, err := exec.Command("modprobe", "-va", "ip_vs").CombinedOutput(); err != nil {
logrus.Warnf("Running modprobe ip_vs failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
}
ipvsFamily, err = getIPVSFamily()
if err != nil {
logrus.Errorf("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.")
}
})
}
func fillService(s *Service) nl.NetlinkRequestData {
cmdAttr := nl.NewRtAttr(ipvsCmdAttrService, nil)
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrAddressFamily, nl.Uint16Attr(s.AddressFamily))
if s.FWMark != 0 {
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrFWMark, nl.Uint32Attr(s.FWMark))
} else {
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrProtocol, nl.Uint16Attr(s.Protocol))
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrAddress, rawIPData(s.Address))
// Port needs to be in network byte order.
portBuf := new(bytes.Buffer)
binary.Write(portBuf, binary.BigEndian, s.Port)
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrPort, portBuf.Bytes())
}
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrSchedName, nl.ZeroTerminated(s.SchedName))
if s.PEName != "" {
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrPEName, nl.ZeroTerminated(s.PEName))
}
f := &ipvsFlags{
flags: s.Flags,
mask: 0xFFFFFFFF,
}
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrFlags, f.Serialize())
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrTimeout, nl.Uint32Attr(s.Timeout))
nl.NewRtAttrChild(cmdAttr, ipvsSvcAttrNetmask, nl.Uint32Attr(s.Netmask))
return cmdAttr
}
func fillDestinaton(d *Destination) nl.NetlinkRequestData {
cmdAttr := nl.NewRtAttr(ipvsCmdAttrDest, nil)
nl.NewRtAttrChild(cmdAttr, ipvsDestAttrAddress, rawIPData(d.Address))
// Port needs to be in network byte order.
portBuf := new(bytes.Buffer)
binary.Write(portBuf, binary.BigEndian, d.Port)
nl.NewRtAttrChild(cmdAttr, ipvsDestAttrPort, portBuf.Bytes())
nl.NewRtAttrChild(cmdAttr, ipvsDestAttrForwardingMethod, nl.Uint32Attr(d.ConnectionFlags&ConnectionFlagFwdMask))
nl.NewRtAttrChild(cmdAttr, ipvsDestAttrWeight, nl.Uint32Attr(uint32(d.Weight)))
nl.NewRtAttrChild(cmdAttr, ipvsDestAttrUpperThreshold, nl.Uint32Attr(d.UpperThreshold))
nl.NewRtAttrChild(cmdAttr, ipvsDestAttrLowerThreshold, nl.Uint32Attr(d.LowerThreshold))
return cmdAttr
}
func (i *Handle) doCmd(s *Service, d *Destination, cmd uint8) error {
req := newIPVSRequest(cmd)
req.AddData(fillService(s))
if d != nil {
req.AddData(fillDestinaton(d))
}
if _, err := execute(i.sock, req, 0); err != nil {
return err
}
return nil
}
func getIPVSFamily() (int, error) {
sock, err := nl.GetNetlinkSocketAt(netns.None(), netns.None(), syscall.NETLINK_GENERIC)
if err != nil {
return 0, err
}
req := newGenlRequest(genlCtrlID, genlCtrlCmdGetFamily)
req.AddData(nl.NewRtAttr(genlCtrlAttrFamilyName, nl.ZeroTerminated("IPVS")))
msgs, err := execute(sock, req, 0)
if err != nil {
return 0, err
}
for _, m := range msgs {
hdr := deserializeGenlMsg(m)
attrs, err := nl.ParseRouteAttr(m[hdr.Len():])
if err != nil {
return 0, err
}
for _, attr := range attrs {
switch int(attr.Attr.Type) {
case genlCtrlAttrFamilyID:
return int(native.Uint16(attr.Value[0:2])), nil
}
}
}
return 0, fmt.Errorf("no family id in the netlink response")
}
func rawIPData(ip net.IP) []byte {
family := nl.GetIPFamily(ip)
if family == nl.FAMILY_V4 {
return ip.To4()
}
return ip
}
func newIPVSRequest(cmd uint8) *nl.NetlinkRequest {
return newGenlRequest(ipvsFamily, cmd)
}
func newGenlRequest(familyID int, cmd uint8) *nl.NetlinkRequest {
req := nl.NewNetlinkRequest(familyID, syscall.NLM_F_ACK)
req.AddData(&genlMsgHdr{cmd: cmd, version: 1})
return req
}
func execute(s *nl.NetlinkSocket, req *nl.NetlinkRequest, resType uint16) ([][]byte, error) {
var (
err error
)
if err := s.Send(req); err != nil {
return nil, err
}
pid, err := s.GetPid()
if err != nil {
return nil, err
}
var res [][]byte
done:
for {
msgs, err := s.Receive()
if err != nil {
return nil, err
}
for _, m := range msgs {
if m.Header.Seq != req.Seq {
return nil, fmt.Errorf("Wrong Seq nr %d, expected %d", m.Header.Seq, req.Seq)
}
if m.Header.Pid != pid {
return nil, fmt.Errorf("Wrong pid %d, expected %d", m.Header.Pid, pid)
}
if m.Header.Type == syscall.NLMSG_DONE {
break done
}
if m.Header.Type == syscall.NLMSG_ERROR {
error := int32(native.Uint32(m.Data[0:4]))
if error == 0 {
break done
}
return nil, syscall.Errno(-error)
}
if resType != 0 && m.Header.Type != resType {
continue
}
res = append(res, m.Data)
if m.Header.Flags&syscall.NLM_F_MULTI == 0 {
break done
}
}
}
return res, nil
}