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Use temporary name for netdevice when moving in/out of NS #1002

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merged 1 commit into from
Mar 12, 2024
Merged

Use temporary name for netdevice when moving in/out of NS #1002

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150 changes: 132 additions & 18 deletions plugins/main/host-device/host-device.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -199,34 +199,112 @@ func cmdDel(args *skel.CmdArgs) error {
return nil
}

// setTempName sets a temporary name for netdevice, returns updated Link object or error
// if occurred.
func setTempName(dev netlink.Link) (netlink.Link, error) {
tempName := fmt.Sprintf("%s%d", "temp_", dev.Attrs().Index)

// rename to tempName
if err := netlink.LinkSetName(dev, tempName); err != nil {
return nil, fmt.Errorf("failed to rename device %q to %q: %v", dev.Attrs().Name, tempName, err)
}

// Get updated Link obj
tempDev, err := netlink.LinkByName(tempName)
if err != nil {
return nil, fmt.Errorf("failed to find %q after rename to %q: %v", dev.Attrs().Name, tempName, err)
}

return tempDev, nil
}

func moveLinkIn(hostDev netlink.Link, containerNs ns.NetNS, ifName string) (netlink.Link, error) {
if err := netlink.LinkSetNsFd(hostDev, int(containerNs.Fd())); err != nil {
return nil, err
origLinkFlags := hostDev.Attrs().Flags
hostDevName := hostDev.Attrs().Name
defaultNs, err := ns.GetCurrentNS()
if err != nil {
return nil, fmt.Errorf("failed to get host namespace: %v", err)
}

// Devices can be renamed only when down
if err = netlink.LinkSetDown(hostDev); err != nil {
return nil, fmt.Errorf("failed to set %q down: %v", hostDev.Attrs().Name, err)
}

// restore original link state in case of error
defer func() {
if err != nil {
if origLinkFlags&net.FlagUp == net.FlagUp && hostDev != nil {
_ = netlink.LinkSetUp(hostDev)
}
}
}()

hostDev, err = setTempName(hostDev)
if err != nil {
return nil, fmt.Errorf("failed to rename device %q to temporary name: %v", hostDevName, err)
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If moveLinkIn() is called with interface Up and failed at here (or later), then the interface goes down and not up. I suppose to add the code to revert (i.e. LinkSetUp()) at error-return case.

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added logic to restore netdev:

  • bring back to host namespace
  • retore netdev name
  • restore link status

}

// restore original netdev name in case of error
defer func() {
if err != nil && hostDev != nil {
_ = netlink.LinkSetName(hostDev, hostDevName)
}
}()

if err = netlink.LinkSetNsFd(hostDev, int(containerNs.Fd())); err != nil {
return nil, fmt.Errorf("failed to move %q to container ns: %v", hostDev.Attrs().Name, err)
}

var contDev netlink.Link
if err := containerNs.Do(func(_ ns.NetNS) error {
tempDevName := hostDev.Attrs().Name
if err = containerNs.Do(func(_ ns.NetNS) error {
var err error
contDev, err = netlink.LinkByName(hostDev.Attrs().Name)
contDev, err = netlink.LinkByName(tempDevName)
if err != nil {
return fmt.Errorf("failed to find %q: %v", hostDev.Attrs().Name, err)
}
// Devices can be renamed only when down
if err = netlink.LinkSetDown(contDev); err != nil {
return fmt.Errorf("failed to set %q down: %v", hostDev.Attrs().Name, err)
return fmt.Errorf("failed to find %q: %v", tempDevName, err)
}

// move netdev back to host namespace in case of error
defer func() {
if err != nil {
_ = netlink.LinkSetNsFd(contDev, int(defaultNs.Fd()))
// we need to get updated link object as link was moved back to host namepsace
_ = defaultNs.Do(func(_ ns.NetNS) error {
hostDev, _ = netlink.LinkByName(tempDevName)
return nil
})
}
}()

// Save host device name into the container device's alias property
if err := netlink.LinkSetAlias(contDev, hostDev.Attrs().Name); err != nil {
return fmt.Errorf("failed to set alias to %q: %v", hostDev.Attrs().Name, err)
if err = netlink.LinkSetAlias(contDev, hostDevName); err != nil {
return fmt.Errorf("failed to set alias to %q: %v", tempDevName, err)
}
// Rename container device to respect args.IfName
if err := netlink.LinkSetName(contDev, ifName); err != nil {
return fmt.Errorf("failed to rename device %q to %q: %v", hostDev.Attrs().Name, ifName, err)
if err = netlink.LinkSetName(contDev, ifName); err != nil {
return fmt.Errorf("failed to rename device %q to %q: %v", tempDevName, ifName, err)
}

// restore tempDevName in case of error
defer func() {
if err != nil {
_ = netlink.LinkSetName(contDev, tempDevName)
}
}()

// Bring container device up
if err = netlink.LinkSetUp(contDev); err != nil {
return fmt.Errorf("failed to set %q up: %v", ifName, err)
}

// bring device down in case of error
defer func() {
if err != nil {
_ = netlink.LinkSetDown(contDev)
}
}()

// Retrieve link again to get up-to-date name and attributes
contDev, err = netlink.LinkByName(ifName)
if err != nil {
Expand All @@ -247,11 +325,14 @@ func moveLinkOut(containerNs ns.NetNS, ifName string) error {
}
defer defaultNs.Close()

return containerNs.Do(func(_ ns.NetNS) error {
var tempName string
var origDev netlink.Link
err = containerNs.Do(func(_ ns.NetNS) error {
dev, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to find %q: %v", ifName, err)
}
origDev = dev

// Devices can be renamed only when down
if err = netlink.LinkSetDown(dev); err != nil {
Expand All @@ -269,16 +350,49 @@ func moveLinkOut(containerNs ns.NetNS, ifName string) error {
}
}()

// Rename the device to its original name from the host namespace
if err = netlink.LinkSetName(dev, dev.Attrs().Alias); err != nil {
return fmt.Errorf("failed to restore %q to original name %q: %v", ifName, dev.Attrs().Alias, err)
newLink, err := setTempName(dev)
if err != nil {
return fmt.Errorf("failed to rename device %q to temporary name: %v", ifName, err)
}
dev = newLink
tempName = dev.Attrs().Name

if err = netlink.LinkSetNsFd(dev, int(defaultNs.Fd())); err != nil {
return fmt.Errorf("failed to move %q to host netns: %v", dev.Attrs().Alias, err)
return fmt.Errorf("failed to move %q to host netns: %v", tempName, err)
}
return nil
})

if err != nil {
return err
}

// Rename the device to its original name from the host namespace
tempDev, err := netlink.LinkByName(tempName)
if err != nil {
return fmt.Errorf("failed to find %q in host namespace: %v", tempName, err)
}

if err = netlink.LinkSetName(tempDev, tempDev.Attrs().Alias); err != nil {
// move device back to container ns so it may be retired
defer func() {
_ = netlink.LinkSetNsFd(tempDev, int(containerNs.Fd()))
_ = containerNs.Do(func(_ ns.NetNS) error {
lnk, err := netlink.LinkByName(tempName)
if err != nil {
return err
}
_ = netlink.LinkSetName(lnk, ifName)
if origDev.Attrs().Flags&net.FlagUp == net.FlagUp {
_ = netlink.LinkSetUp(lnk)
}
return nil
})
}()
return fmt.Errorf("failed to restore %q to original name %q: %v", tempName, tempDev.Attrs().Alias, err)
}

return nil
}

func hasDpdkDriver(pciaddr string) (bool, error) {
Expand Down
108 changes: 108 additions & 0 deletions plugins/main/host-device/host-device_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1149,6 +1149,114 @@ var _ = Describe("base functionality", func() {
return nil
})
})

It(fmt.Sprintf("Test CmdAdd/Del when additioinal interface alreay exists in container ns with same name. %s config", ver), func() {
var (
origLink netlink.Link
containerLink netlink.Link
)

hostIfname := "eth0"
containerAdditionalIfname := "eth0"

// prepare host device in original namespace
_ = originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
err := netlink.LinkAdd(&netlink.Dummy{
LinkAttrs: netlink.LinkAttrs{
Name: hostIfname,
},
})
Expect(err).NotTo(HaveOccurred())
origLink, err = netlink.LinkByName(hostIfname)
Expect(err).NotTo(HaveOccurred())
err = netlink.LinkSetUp(origLink)
Expect(err).NotTo(HaveOccurred())
return nil
})

// prepare device in container namespace with same name as host device
_ = targetNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
err := netlink.LinkAdd(&netlink.Dummy{
LinkAttrs: netlink.LinkAttrs{
Name: containerAdditionalIfname,
},
})
Expect(err).NotTo(HaveOccurred())
containerLink, err = netlink.LinkByName(containerAdditionalIfname)
Expect(err).NotTo(HaveOccurred())
err = netlink.LinkSetUp(containerLink)
Expect(err).NotTo(HaveOccurred())
return nil
})

// call CmdAdd
cniName := "net1"
conf := fmt.Sprintf(`{
"cniVersion": "%s",
"name": "cni-plugin-host-device-test",
"type": "host-device",
"device": %q
}`, ver, hostIfname)
args := &skel.CmdArgs{
ContainerID: "dummy",
Netns: targetNS.Path(),
IfName: cniName,
StdinData: []byte(conf),
}
var resI types.Result
err := originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
var err error
resI, _, err = testutils.CmdAddWithArgs(args, func() error { return cmdAdd(args) })
return err
})
Expect(err).NotTo(HaveOccurred())

// check that the result was sane
t := newTesterByVersion(ver)
t.expectInterfaces(resI, cniName, origLink.Attrs().HardwareAddr.String(), targetNS.Path())

// assert that host device is now in the target namespace and is up
_ = targetNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
link, err := netlink.LinkByName(cniName)
Expect(err).NotTo(HaveOccurred())
Expect(link.Attrs().HardwareAddr).To(Equal(origLink.Attrs().HardwareAddr))
Expect(link.Attrs().Flags & net.FlagUp).To(Equal(net.FlagUp))
return nil
})

// call CmdDel, expect it to succeed
_ = originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
err = testutils.CmdDelWithArgs(args, func() error {
return cmdDel(args)
})
Expect(err).ToNot(HaveOccurred())
return nil
})

// assert container interface "eth0" still exists in target namespace and is up
err = targetNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
link, err := netlink.LinkByName(containerAdditionalIfname)
Expect(err).NotTo(HaveOccurred())
Expect(link.Attrs().HardwareAddr).To(Equal(containerLink.Attrs().HardwareAddr))
Expect(link.Attrs().Flags & net.FlagUp).To(Equal(net.FlagUp))
return nil
})
Expect(err).NotTo(HaveOccurred())

// assert that host device is now back in the original namespace
_ = originalNS.Do(func(ns.NetNS) error {
defer GinkgoRecover()
_, err := netlink.LinkByName(hostIfname)
Expect(err).NotTo(HaveOccurred())
return nil
})
})
}
})

Expand Down