Use temporary name for netdevice when moving in/out of NS
Today, it is not possible to use host-device CNI to move a host device to container namespace if a device already exists in that namespace. e.g when a delegate plugin (such as multus) is used to provide multiple networks to a container, CNI Add call will fail if the targeted host device name already exists in container network namespace. to overcome this, we use a temporary name for the interface before moving it in/out of container network namespace. Signed-off-by: adrianc <adrianc@nvidia.com>
This commit is contained in:
adrianc
@ -199,34 +199,112 @@ func cmdDel(args *skel.CmdArgs) error {
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return nil
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}
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// setTempName sets a temporary name for netdevice, returns updated Link object or error
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// if occurred.
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func setTempName(dev netlink.Link) (netlink.Link, error) {
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tempName := fmt.Sprintf("%s%d", "temp_", dev.Attrs().Index)
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// rename to tempName
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if err := netlink.LinkSetName(dev, tempName); err != nil {
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return nil, fmt.Errorf("failed to rename device %q to %q: %v", dev.Attrs().Name, tempName, err)
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}
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// Get updated Link obj
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tempDev, err := netlink.LinkByName(tempName)
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if err != nil {
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return nil, fmt.Errorf("failed to find %q after rename to %q: %v", dev.Attrs().Name, tempName, err)
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}
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return tempDev, nil
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}
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func moveLinkIn(hostDev netlink.Link, containerNs ns.NetNS, ifName string) (netlink.Link, error) {
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if err := netlink.LinkSetNsFd(hostDev, int(containerNs.Fd())); err != nil {
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return nil, err
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origLinkFlags := hostDev.Attrs().Flags
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hostDevName := hostDev.Attrs().Name
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defaultNs, err := ns.GetCurrentNS()
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if err != nil {
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return nil, fmt.Errorf("failed to get host namespace: %v", err)
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}
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// Devices can be renamed only when down
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if err = netlink.LinkSetDown(hostDev); err != nil {
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return nil, fmt.Errorf("failed to set %q down: %v", hostDev.Attrs().Name, err)
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}
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// restore original link state in case of error
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defer func() {
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if err != nil {
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if origLinkFlags&net.FlagUp == net.FlagUp && hostDev != nil {
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_ = netlink.LinkSetUp(hostDev)
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}
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}
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}()
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hostDev, err = setTempName(hostDev)
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if err != nil {
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return nil, fmt.Errorf("failed to rename device %q to temporary name: %v", hostDevName, err)
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}
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// restore original netdev name in case of error
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defer func() {
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if err != nil && hostDev != nil {
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_ = netlink.LinkSetName(hostDev, hostDevName)
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}
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}()
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if err = netlink.LinkSetNsFd(hostDev, int(containerNs.Fd())); err != nil {
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return nil, fmt.Errorf("failed to move %q to container ns: %v", hostDev.Attrs().Name, err)
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}
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var contDev netlink.Link
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if err := containerNs.Do(func(_ ns.NetNS) error {
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tempDevName := hostDev.Attrs().Name
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if err = containerNs.Do(func(_ ns.NetNS) error {
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var err error
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contDev, err = netlink.LinkByName(hostDev.Attrs().Name)
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contDev, err = netlink.LinkByName(tempDevName)
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if err != nil {
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return fmt.Errorf("failed to find %q: %v", hostDev.Attrs().Name, err)
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}
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// Devices can be renamed only when down
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if err = netlink.LinkSetDown(contDev); err != nil {
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return fmt.Errorf("failed to set %q down: %v", hostDev.Attrs().Name, err)
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return fmt.Errorf("failed to find %q: %v", tempDevName, err)
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}
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// move netdev back to host namespace in case of error
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defer func() {
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if err != nil {
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_ = netlink.LinkSetNsFd(contDev, int(defaultNs.Fd()))
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// we need to get updated link object as link was moved back to host namepsace
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_ = defaultNs.Do(func(_ ns.NetNS) error {
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hostDev, _ = netlink.LinkByName(tempDevName)
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return nil
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})
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}
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}()
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// Save host device name into the container device's alias property
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if err := netlink.LinkSetAlias(contDev, hostDev.Attrs().Name); err != nil {
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return fmt.Errorf("failed to set alias to %q: %v", hostDev.Attrs().Name, err)
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if err = netlink.LinkSetAlias(contDev, hostDevName); err != nil {
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return fmt.Errorf("failed to set alias to %q: %v", tempDevName, err)
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}
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// Rename container device to respect args.IfName
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if err := netlink.LinkSetName(contDev, ifName); err != nil {
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return fmt.Errorf("failed to rename device %q to %q: %v", hostDev.Attrs().Name, ifName, err)
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if err = netlink.LinkSetName(contDev, ifName); err != nil {
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return fmt.Errorf("failed to rename device %q to %q: %v", tempDevName, ifName, err)
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}
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// restore tempDevName in case of error
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defer func() {
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if err != nil {
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_ = netlink.LinkSetName(contDev, tempDevName)
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}
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}()
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// Bring container device up
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if err = netlink.LinkSetUp(contDev); err != nil {
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return fmt.Errorf("failed to set %q up: %v", ifName, err)
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}
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// bring device down in case of error
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defer func() {
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if err != nil {
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_ = netlink.LinkSetDown(contDev)
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}
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}()
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// Retrieve link again to get up-to-date name and attributes
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contDev, err = netlink.LinkByName(ifName)
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if err != nil {
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@ -247,11 +325,14 @@ func moveLinkOut(containerNs ns.NetNS, ifName string) error {
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}
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defer defaultNs.Close()
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return containerNs.Do(func(_ ns.NetNS) error {
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var tempName string
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var origDev netlink.Link
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err = containerNs.Do(func(_ ns.NetNS) error {
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dev, err := netlink.LinkByName(ifName)
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if err != nil {
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return fmt.Errorf("failed to find %q: %v", ifName, err)
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}
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origDev = dev
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// Devices can be renamed only when down
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if err = netlink.LinkSetDown(dev); err != nil {
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@ -269,16 +350,49 @@ func moveLinkOut(containerNs ns.NetNS, ifName string) error {
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}
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}()
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// Rename the device to its original name from the host namespace
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if err = netlink.LinkSetName(dev, dev.Attrs().Alias); err != nil {
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return fmt.Errorf("failed to restore %q to original name %q: %v", ifName, dev.Attrs().Alias, err)
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newLink, err := setTempName(dev)
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if err != nil {
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return fmt.Errorf("failed to rename device %q to temporary name: %v", ifName, err)
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}
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dev = newLink
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tempName = dev.Attrs().Name
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if err = netlink.LinkSetNsFd(dev, int(defaultNs.Fd())); err != nil {
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return fmt.Errorf("failed to move %q to host netns: %v", dev.Attrs().Alias, err)
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return fmt.Errorf("failed to move %q to host netns: %v", tempName, err)
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}
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return nil
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})
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if err != nil {
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return err
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}
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// Rename the device to its original name from the host namespace
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tempDev, err := netlink.LinkByName(tempName)
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if err != nil {
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return fmt.Errorf("failed to find %q in host namespace: %v", tempName, err)
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}
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if err = netlink.LinkSetName(tempDev, tempDev.Attrs().Alias); err != nil {
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// move device back to container ns so it may be retired
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defer func() {
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_ = netlink.LinkSetNsFd(tempDev, int(containerNs.Fd()))
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_ = containerNs.Do(func(_ ns.NetNS) error {
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lnk, err := netlink.LinkByName(tempName)
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if err != nil {
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return err
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}
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_ = netlink.LinkSetName(lnk, ifName)
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if origDev.Attrs().Flags&net.FlagUp == net.FlagUp {
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_ = netlink.LinkSetUp(lnk)
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}
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return nil
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})
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}()
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return fmt.Errorf("failed to restore %q to original name %q: %v", tempName, tempDev.Attrs().Alias, err)
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}
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return nil
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}
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func hasDpdkDriver(pciaddr string) (bool, error) {
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