[Flake] Investigate netlink dnscache errors

[aojea]

It can be observed in CI jobs, the fact that the errors are differnt by ip family is also concerning, but you can see errors of type on the CI jobs,:

2025-01-15T10:06:48.602974491Z stderr F I0115 10:06:48.568344 1 agent.go:208] "Could not receive message" error="netlink receive: no such file or directory"

IPv4 job example:

2025-01-15T10:06:48.904578964Z stderr F E0115 10:06:48.896584       1 agent.go:514] "fail to get dns response over TCP" err="header error: server temporary mishbehaving, header rcode 2 extended rcode false rcode ServerFailure" header={"ID":39062,"Response":false,"OpCode":0,"Authoritative":false,"Truncated":false,"RecursionDesired":true,"RecursionAvailable":false,"AuthenticData":false,"CheckingDisabled":false,"RCode":0}
2025-01-15T10:06:49.360945053Z stderr F E0115 10:06:49.318902       1 agent.go:514] "fail to get dns response over TCP" err="header error: server temporary mishbehaving, header rcode 2 extended rcode false rcode ServerFailure" header={"ID":6487,"Response":false,"OpCode":0,"Authoritative":false,"Truncated":false,"RecursionDesired":true,"RecursionAvailable":false,"AuthenticData":false,"CheckingDisabled":false,"RCode":0}
2025-01-15T10:06:49.360961233Z stderr F E0115 10:06:49.330008       1 agent.go:514] "fail to get dns response over TCP" err="header error: server temporary mishbehaving, header rcode 2 extended rcode false rcode ServerFailure" header={"ID":6487,"Response":false,"OpCode":0,"Authoritative":false,"Truncated":false,"RecursionDesired

[aojea]

Another one

https://github.com/aojea/kindnet/actions/runs/12984544447

2025-01-27T08:18:33.6869410Z �[38;5;9m[FAILED] service is not reachable within 2m0s timeout on endpoint nodeport-update-service:80 over TCP protocol�[0m
2025-01-27T08:18:33.6870097Z �[38;5;9mIn �[1m[It]�[0m�[38;5;9m at: �[1mk8s.io/kubernetes/test/e2e/network/service.go:1357�[0m �[38;5;243m@ 01/27/25 08:18:33.549�[0m
2025-01-27T08:18:33.6870542Z �[38;5;243m------------

2025-01-27T08:17:11.613826829Z stderr F I0127 08:17:11.613496       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.613843941Z stderr F I0127 08:17:11.613536       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.640594841Z stderr F I0127 08:17:11.640268       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.640607755Z stderr F I0127 08:17:11.640302       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.640613085Z stderr F I0127 08:17:11.640328       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.640617964Z stderr F I0127 08:17:11.640347       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.640622483Z stderr F I0127 08:17:11.640370       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.640635116Z stderr F I0127 08:17:11.640395       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"
2025-01-27T08:17:11.640638222Z stderr F I0127 08:17:11.640449       1 agent.go:207] "Could not receive message" error="netlink receive: no such file or directory"

coming from line 207 here

kindnet/pkg/dnscache/agent.go

Lines 201 to 209 in 3929693

	err = nf.RegisterWithErrorFunc(ctx, fn, func(err error) int {
	if opError, ok := err.(*netlink.OpError); ok {
	if opError.Timeout() || opError.Temporary() {
	return 0
	}
	}
	logger.Info("Could not receive message", "error", err)
	return 0
	})

@florianl I'm using your project https://github.com/florianl/go-nfqueue , I'm using the same project for the kube-network-policies but I didn't see this problem, is this error something you have seen before?