Declare nftables before the guard's table, so a node joining adopted without nft can load it (hq ADR 0103)

internal/catalogue/adoption.go

@@ -45,6 +45,13 @@ func GuardID() string        { return AdoptionPrefix + "guard" }
 func GuardUnitID() string    { return AdoptionPrefix + "guard-unit" }
 func GuardRunningID() string { return AdoptionPrefix + "guard-running" }
 
+// GuardPackageID is the tool that loads the guard, declared first: a node joining adopted has
+// no filter module and may have no nft at all, and a table nothing can load guards nothing.
+func GuardPackageID() string { return AdoptionPrefix + "guard-package" }
+
+// GuardPackage is the package that carries nft.
+const GuardPackage = "nftables"
+
 // OpeningID is an opening's resource identity: its protocol, port and path say what it is.
 func OpeningID(protocol string, port int, path string) string {
 	return fmt.Sprintf("%sopening-%s-%d-%s", AdoptionPrefix, protocol, port, path)
@@ -148,10 +155,9 @@ func Published(resources []map[string]any) map[string]map[int]int {
 // the machine serves; and it is the mesh's own table, so the found firewall reloading does not
 // touch it. It refuses only packets addressed to this machine, and the ports except from the
 // machine itself — its loopback and the container runtime's own networks — and from the private
-// network, known by the interface a packet arrives
+// network, known by the interface a packet arrives on and never by its source address. At
-// on and never by its source address. At prerouting, ahead of the runtime's destination
+// prerouting, ahead of the runtime's destination translation, so it matches the port the packet
-// translation, so it matches the port the packet was sent to; in the inet family, so both address
+// was sent to; in the inet family, so both address families.
-// families.
 //
 // The same text the installer raises on an adopted genesis; a test holds both to it.
 func AsGuard(ports []int) string {
@@ -200,14 +206,15 @@ func GuardUnitText() string {
 		"WantedBy=multi-user.target\n"
 }
 
-// GuardResources are the guard as three resources of the existing kinds: the table, the unit, and
+// GuardResources are the guard as four resources of the existing kinds: the tool that loads it,
-// the unit running, restarted when the table changes. Nothing when there is nothing to guard: an
+// the table, the unit, and the unit running, restarted when the table changes. Nothing when there
-// empty set is not a table nft loads.
+// is nothing to guard: an empty set is not a table nft loads.
 func GuardResources(ports []int) []map[string]any {
 	if len(ports) == 0 {
 		return nil
 	}
 	return []map[string]any{
+		{"id": GuardPackageID(), "type": "package", "package": GuardPackage},
 		{"id": GuardID(), "type": "file", "path": GuardPath, "content": AsGuard(ports),
 			"mode": "0644"},
 		{"id": GuardUnitID(), "type": "file", "path": GuardUnitPath, "content": GuardUnitText(),

internal/catalogue/adoption_test.go

@@ -157,6 +157,23 @@ func TestAnAdoptedNodeLoadsNoFilterOfTheMeshs(t *testing.T) {
 		t.Fatalf("the guard does not guard the store, the broker and its management port:\n%s",
 			guard["content"])
 	}
+	// The tool that loads it comes first, and the table after it: a node joining adopted has no
+	// filter module and may have no nft.
+	pkg, table := -1, -1
+	for i, r := range composed.Resources {
+		switch r["id"] {
+		case GuardPackageID():
+			pkg = i
+			if r["type"] != "package" || r["package"] != "nftables" {
+				t.Fatalf("the guard's package is %v", r)
+			}
+		case GuardID():
+			table = i
+		}
+	}
+	if pkg < 0 || pkg > table {
+		t.Fatalf("nftables is not declared before the guard's table (%d, %d)", pkg, table)
+	}
 	if !reflect.DeepEqual(got[GuardRunningID()]["restart-on"], []any{GuardID(), GuardUnitID()}) {
 		t.Fatalf("the guard is not reloaded when its table changes: %v", got[GuardRunningID()])
 	}