DebTik/internal/firewall/nat_chain_test.go

package firewall

import (
	"strings"
	"testing"
)

func TestChainPlacement(t *testing.T) {
	cases := []struct {
		kind  string
		rule  any
		valid bool
	}{
		{"nat", NATRule{Chain: "dstnat", Action: "dst-nat"}, true},
		{"nat", NATRule{Chain: "prerouting", Action: "dst-nat"}, true},
		{"nat", NATRule{Chain: "output", Action: "dst-nat"}, true},
		{"nat", NATRule{Chain: "custom", Action: "dst-nat"}, true},
		{"nat", NATRule{Chain: "srcnat", Action: "dst-nat"}, false},
		{"nat", NATRule{Chain: "forward", Action: "accept"}, false},
		{"nat", NATRule{Chain: "srcnat", Action: "masquerade", OutInterface: "eth0"}, true},
		{"nat", NATRule{Chain: "input", Action: "masquerade"}, false},
		{"nat", NATRule{Chain: "prerouting", Action: "accept", OutInterface: "eth0"}, false},
		{"filter", FilterRule{Chain: "prerouting", Action: "accept"}, false},
		{"filter", FilterRule{Chain: "input", Action: "accept", OutInterface: "eth0"}, false},
		{"mangle", MangleRule{Chain: "output", Action: "accept", InInterface: "eth0"}, false},
		{"mangle", MangleRule{Chain: "forward", Action: "accept", InInterface: "eth0", OutInterface: "eth1"}, true},
	}
	for _, c := range cases {
		err := validateChainPlacement(c.kind, c.rule)
		if (err == nil) != c.valid {
			t.Errorf("%s %#v: %v", c.kind, c.rule, err)
		}
	}
}

func TestNATChainHooks(t *testing.T) {
	rules := []NATRule{{ID: "incoming", Chain: "dstnat", Action: "dst-nat", ToAddresses: "192.0.2.1"}, {ID: "local", Chain: "output", Action: "dst-nat", ToAddresses: "192.0.2.2"}, {ID: "outgoing", Chain: "srcnat", Action: "masquerade"}}
	payload := ownedPayload(BuildIPTablesRestore(nil, rules, nil), "")
	for _, want := range []string{"-A DT_nat_PREROUTING ", "-A DT_nat_OUTPUT ", "-A DT_nat_POSTROUTING ", "-I PREROUTING 1 -m comment --comment debtik:hook -j DT_nat_PREROUTING", "-I OUTPUT 1 -m comment --comment debtik:hook -j DT_nat_OUTPUT", "-I POSTROUTING 1 -m comment --comment debtik:hook -j DT_nat_POSTROUTING"} {
		if !strings.Contains(payload, want) {
			t.Errorf("missing %s", want)
		}
	}
}