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OCPBUGS-21831: [release-4.14] Set MAC address after renaming the interface #92

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merged 1 commit into from
Oct 20, 2023
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OCPBUGS-21831: [release-4.14] Set MAC address after renaming the interface #92

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28 changes: 15 additions & 13 deletions pkg/sriov/sriov.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ package sriov

import (
"fmt"

"github.com/containernetworking/plugins/pkg/ns"

sriovtypes "github.com/k8snetworkplumbingwg/sriov-cni/pkg/types"
Expand Down Expand Up @@ -65,6 +66,9 @@ func (s *sriovManager) SetupVF(conf *sriovtypes.NetConf, podifName string, netns
return fmt.Errorf("error getting VF netdevice with name %s", linkName)
}

// Save the original effective MAC address before overriding it
conf.OrigVfState.EffectiveMAC = linkObj.Attrs().HardwareAddr.String()

// tempName used as intermediary name to avoid name conflicts
tempName := fmt.Sprintf("%s%d", "temp_", linkObj.Attrs().Index)

Expand All @@ -78,31 +82,29 @@ func (s *sriovManager) SetupVF(conf *sriovtypes.NetConf, podifName string, netns
return fmt.Errorf("error setting temp IF name %s for %s", tempName, linkName)
}

// Save the original effective MAC address before overriding it
conf.OrigVfState.EffectiveMAC = linkObj.Attrs().HardwareAddr.String()
// 3. Set MAC address
if conf.MAC != "" {
err = utils.SetVFEffectiveMAC(s.nLink, tempName, conf.MAC)
if err != nil {
return fmt.Errorf("failed to set netlink MAC address to %s: %v", conf.MAC, err)
}
}

// 4. Change netns
// 3. Change netns
if err := s.nLink.LinkSetNsFd(linkObj, int(netns.Fd())); err != nil {
return fmt.Errorf("failed to move IF %s to netns: %q", tempName, err)
}

if err := netns.Do(func(_ ns.NetNS) error {
// 5. Set Pod IF name
// 4. Set Pod IF name
if err := s.nLink.LinkSetName(linkObj, podifName); err != nil {
return fmt.Errorf("error setting container interface name %s for %s", linkName, tempName)
}

// 6. Enable IPv4 ARP notify and IPv6 Network Discovery notify
// 5. Enable IPv4 ARP notify and IPv6 Network Discovery notify
// Error is ignored here because enabling this feature is only a performance enhancement.
_ = s.utils.EnableArpAndNdiscNotify(podifName)

// 6. Set MAC address
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Oh I did not catch this in U/S sriov-cni. But setting the MAC address after we send out GARPs may be an issue. Since ARPs require that the MAC address is setup properly.

You are moving SetVFEffectiveMAC down to solve a race condition, is that correct? So moving it before EnableArpAndNdiscNotify shouldn't be any different (although solving race conditions this way really is a toss of the coin).

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Oh I did not catch this in U/S sriov-cni. But setting the MAC address after we send out GARPs may be an issue. Since ARPs require that the MAC address is setup properly.

Does the GARP go out before setting up the interface? That happens on step 7

You are moving SetVFEffectiveMAC down to solve a race condition, is that correct? So moving it before EnableArpAndNdiscNotify shouldn't be any different (although solving race conditions this way really is a toss of the coin).

I agree, that's the best we could do from the CNI side while the investigation on the kernel side is still ongoing.
As the root cause is not yet clear, moving that statement can make a difference. At least, we should run an extensive test suite as we did with these changes.

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Sorry, I forgot that it is also done after IPAM. Then this is lgtm.

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It actually doesn't happen at step 7 but after IPAM is setup.

if conf.MAC != "" {
err = utils.SetVFEffectiveMAC(s.nLink, podifName, conf.MAC)
if err != nil {
return fmt.Errorf("failed to set netlink MAC address to %s: %v", conf.MAC, err)
}
}

// 7. Bring IF up in Pod netns
if err := s.nLink.LinkSetUp(linkObj); err != nil {
return fmt.Errorf("error bringing interface up in container ns: %q", err)
Expand Down
11 changes: 6 additions & 5 deletions pkg/sriov/sriov_test.go
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Original file line number Diff line number Diff line change
@@ -1,9 +1,10 @@
package sriov

import (
"github.com/k8snetworkplumbingwg/sriov-cni/pkg/utils"
"net"

"github.com/k8snetworkplumbingwg/sriov-cni/pkg/utils"

"github.com/containernetworking/plugins/pkg/ns"
"github.com/containernetworking/plugins/pkg/testutils"
"github.com/k8snetworkplumbingwg/sriov-cni/pkg/sriov/mocks"
Expand Down Expand Up @@ -100,17 +101,17 @@ var _ = Describe("Sriov", func() {
HardwareAddr: fakeMac,
}}

tempLink := &utils.FakeLink{LinkAttrs: netlink.LinkAttrs{
net1Link := &utils.FakeLink{LinkAttrs: netlink.LinkAttrs{
Index: 1000,
Name: "temp_1000",
Name: "net1",
HardwareAddr: expMac,
}}

mocked.On("LinkByName", "enp175s6").Return(fakeLink, nil)
mocked.On("LinkByName", "temp_1000").Return(tempLink, nil)
mocked.On("LinkByName", "net1").Return(net1Link, nil)
mocked.On("LinkSetDown", fakeLink).Return(nil)
mocked.On("LinkSetName", fakeLink, mock.Anything).Return(nil)
mocked.On("LinkSetHardwareAddr", tempLink, expMac).Return(nil)
mocked.On("LinkSetHardwareAddr", net1Link, expMac).Return(nil)
mocked.On("LinkSetNsFd", fakeLink, mock.AnythingOfType("int")).Return(nil)
mocked.On("LinkSetUp", fakeLink).Return(nil)
mockedPciUtils.On("EnableArpAndNdiscNotify", mock.AnythingOfType("string")).Return(nil)
Expand Down