Function ForwardExists

pkg/testutil/iptables/iptables_linux.go:29–56

ForwardExists check that at least 2 rules are present in the CNI-HOSTPORT-DNAT chain and checks for regex matches in the list of rules

(t *testing.T, ipt *iptables.IPTables, chain, containerIP string, port int)

// ForwardExists check that at least 2 rules are present in the CNI-HOSTPORT-DNAT chain
// and checks for regex matches in the list of rules
func ForwardExists(t *testing.T, ipt *iptables.IPTables, chain, containerIP string, port int) bool {
	rules, err := ipt.List("nat", chain)
	if err != nil {
		t.Logf("error listing rules in chain: %q\n", err)
		return false
	}

	if len(rules) < 1 {
		t.Logf("not enough rules: %d", len(rules))
		return false
	}

	// here we check if at least one of the rules in the chain
	// matches the required string to identify that the rule was applied
	found := false
	matchRule := `--dport ` + fmt.Sprintf("%d", port) + ` .+ --to-destination ` + containerIP
	for _, rule := range rules {
		foundInRule, err := regexp.MatchString(matchRule, rule)
		if err != nil {
			t.Logf("error in match string: %q\n", err)
			return false
		}
		if foundInRule {
			found = foundInRule
		}
	}
	return found
}

// GetRedirectedChain returns the chain where the traffic is being redirected.
// This is how libcni manage its port maps.