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ipvs: propagate errors during netlink initialization, and remove logrus dependency #52

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ipvs: propagate errors during netlink initialization, and remove logrus dependency #52

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67cc3e6
ipvs: only close namespace handles when opened
thaJeztah Oct 14, 2026
9264de4
ipvs: propagate errors during netlink initialization
thaJeztah Oct 14, 2026
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1 change: 0 additions & 1 deletion go.mod
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@ module github.com/moby/ipvs
go 1.23

require (
github.com/sirupsen/logrus v1.10.2
github.com/vishvananda/netlink v1.3.1
github.com/vishvananda/netns v0.0.5
golang.org/x/sys v0.13.0
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6 changes: 0 additions & 6 deletions go.sum
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@@ -1,13 +1,7 @@
github.com/sirupsen/logrus v1.10.2 h1:G2SED73/qrAu6YwbdxOD6peLkCBI3z7L+ykJFTXJBBo=
github.com/sirupsen/logrus v1.10.2/go.mod h1:SLEg8TqYulVKKfIGHldVp2K2aYz2DKSVBq4g/H5bR7Q=
github.com/stretchr/testify v1.12.1 h1:EuwCh5fleGS7H32xRwO3wRGT7DxrDhLAT6FF8MpWDWE=
github.com/stretchr/testify v1.12.1/go.mod h1:MDEgiDPPsNp5cuIrHPPCyornHKgEVbtFUmoNlxoYthg=
github.com/vishvananda/netlink v1.3.1 h1:3AEMt62VKqz90r0tmNhog0r/PpWKmrEShJU0wJW6bV0=
github.com/vishvananda/netlink v1.3.1/go.mod h1:ARtKouGSTGchR8aMwmkzC0qiNPrrWO5JS/XMVl45+b4=
github.com/vishvananda/netns v0.0.5 h1:DfiHV+j8bA32MFM7bfEunvT8IAqQ/NzSJHtcmW5zdEY=
github.com/vishvananda/netns v0.0.5/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
go.yaml.in/yaml/v3 v3.0.5 h1:N6y/pJk8buWs9NY5ERU2HSMfm+IuD/OtfdAnq6kESPw=
go.yaml.in/yaml/v3 v3.0.5/go.mod h1:HVTZu1O7/Vkt2N+BFy8Zza+lnLsABggaTM2ZpNIGuKg=
golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
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6 changes: 4 additions & 2 deletions ipvs_linux.go
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Expand Up @@ -84,7 +84,9 @@ type Handle struct {
// passed path. It will return a valid handle or an error in case an
// error occurred while creating the handle.
func New(path string) (*Handle, error) {
setup()
if _, err := ipvsFamily(); err != nil {
return nil, err
}

n := netns.None()
if path != "" {
Expand All @@ -93,8 +95,8 @@ func New(path string) (*Handle, error) {
if err != nil {
return nil, err
}
defer func() { _ = n.Close() }()
}
defer n.Close()

sock, err := nl.GetNetlinkSocketAt(n, netns.None(), unix.NETLINK_GENERIC)
if err != nil {
Expand Down
43 changes: 23 additions & 20 deletions netlink_linux.go
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Expand Up @@ -8,24 +8,18 @@ import (
"math"
"net"
"os/exec"
"strings"
"sync"
"sync/atomic"
"syscall"
"time"

"github.com/sirupsen/logrus"
"github.com/vishvananda/netlink/nl"
"github.com/vishvananda/netns"
"golang.org/x/sys/unix"
)

// For Quick Reference IPVS related netlink message is described at the end of this file.
var (
native = nl.NativeEndian()
ipvsFamily int
ipvsOnce sync.Once
)
var native = nl.NativeEndian()

// genlMsgHdrLen is the serialized size of genlMsgHdr. Keep this explicit
// rather than deriving it with unsafe.Sizeof so the wire format does not
Expand Down Expand Up @@ -71,19 +65,27 @@ func (*ipvsFlags) Len() int {
return ipvsFlagsLen
}

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 lazily discovers and caches the IPVS generic-netlink family ID
// and any initialization error.
var ipvsFamily = sync.OnceValues(func() (int, error) {
family, err := getIPVSFamily()
if err == nil {
return family, nil
}

ipvsFamily, err = getIPVSFamily()
if err != nil {
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.")
}
})
}
// Linux 5.17 added automatic loading of ip_vs through generic-netlink
// family discovery. Older kernels, including RHEL 8's 4.18 kernel,
// may still require explicit module loading.
//
// See https://lists.openwall.net/netdev/2021/11/01/229
_, _ = exec.Command("modprobe", "-va", "ip_vs").CombinedOutput()

family, err = getIPVSFamily()
if err != nil {
return 0, fmt.Errorf("get IPVS generic-netlink family: %w", err)
}
Comment on lines +81 to +86
return family, nil
})

func fillService(s *Service) nl.NetlinkRequestData {
cmdAttr := nl.NewRtAttr(int(ipvsCmdAttrService), nil)
Expand Down Expand Up @@ -218,7 +220,8 @@ func rawIPData(ip net.IP) []byte {
}

func newIPVSRequest(cmd ipvsCmd) *nl.NetlinkRequest {
return newGenlRequest(ipvsFamily, uint8(cmd))
family, _ := ipvsFamily()
return newGenlRequest(family, uint8(cmd))
}

func newGenlRequest(familyID int, cmd uint8) *nl.NetlinkRequest {
Expand Down
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