fix: Delegated ipam not configure ipv6 if ipv6 disabled in agent

[tamilmani1989]

Delegated ipam returns ipv6 address to cilium cni even if ipv6 disabled in cilium agent config. In this scenario, ipv6 node addressing is not set and its causing cilium cni to crash if delegated ipam returns ipv6.

Requires backport to 1.14 and 1.15 versions

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Fixes: #31103

<!-- Fix crash of cilium-cni with delegated IPAM returning ipv6 when IPv6 is disabled in Agent -->

[squeed]

Good catch.

My suggestion would be to fix this on this line instead -- something like

if ipv6IsEnabled(ipam) && conf.Addressing.IPV6 != nil {

And, for extra safety, do the same for ipv4 on line 578.

Make sense?

[tamilmani1989]

Good catch.

My suggestion would be to fix this on this line instead -- something like

if ipv6IsEnabled(ipam) && conf.Addressing.IPV6 != nil {

And, for extra safety, do the same for ipv4 on line 578.

Make sense?

Yep I thought about this. The reason I went with this approach is ipv6IsEnabled returns true even if conf.Addressing.IPV6 is nil . Thats why decided to update in allocateIPsWithDelegatedPlugin to be safer and not to regress. I'm fine adding in the place you suggested if there won't be any issues or even better to make ipv6IsEnabled to return false if ipam.HostAddressing.IPV6 is nil?

	ipam := &models.IPAMResponse{
		HostAddressing: conf.Addressing,
		Address:        &models.AddressPair{},
	}

func ipv6IsEnabled(ipam *models.IPAMResponse) bool {
	if ipam == nil || ipam.Address.IPV6 == "" {
		return false
	}

	**if ipam.HostAddressing != nil && ipam.HostAddressing.IPV6 != nil {
		return ipam.HostAddressing.IPV6.Enabled
	}**

	return true
}

[joestringer]

Hi, I'd suggest a release note in the description like: "Fix crash of cilium-cni with delegated IPAM when IPv6 is disabled". This way users have a decent chance to understand the change and whether this fix may address a problem they are facing.

[joestringer]

/test

[tamilmani1989]

/test

[squeed]

I'm fine adding in the place you suggested if there won't be any issues or even better to make ipv6IsEnabled to return false if ipam.HostAddressing.IPV6 is nil?

@tamilmani1989 let's do both, belt-and-suspenders. allocateIPsWithDelegatedPlugin is really about parsing the ipam result, so it shouldn't care, per se, about configuration. Separately, we should consult configuration before applying the IPAM result to the interface.

[tamilmani1989]

@squeed Thanks for reviewing. Addressed your comment.

[squeed]

/test

[tamilmani1989]

/test

[tamilmani1989]

/test

[tamilmani1989]

/ci-eks