feat(fls): system software settings as Java loads them

readSystemSoftware adds to each node what the topology needs from its
system software: a switch's SSID and learning time, a host's wireless
SSID, a router's RIP switch, the manual routes and the firewall of a
router or home router. All 23 corpus files match Java.

- A router's firewall is one object its constructor hangs in two places;
  the corpus writes it under the web server's "konfig" plug-in. The
  places are merged.
- The decoder keeps entries a constructor made in a map, reached by
  get(key) (installed applications), like the elements of a list.
- The Java oracle loads every file twice and writes values that differ
  as null: what FILIUS rolls (MACs, a switch's SSID) without text search.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/fls/src/javabeans.ts

@@ -53,6 +53,11 @@ export interface JavaObject {
    * result. `add`/`set` go to `calls`, in order.
    */
   readonly presetElements: Map<number, JavaValue>;
+  /**
+   * The same for a map: entries its constructor made (a router's installed
+   * applications), reached by `<void method="get"><string>key</string>`.
+   */
+  readonly presetEntries: Map<string, JavaValue>;
   /** True when the object was not in the file but returned by a getter. */
   readonly fromGetter: boolean;
 }
@@ -139,12 +144,21 @@ function replayList(value: JavaObject, constructed: number): (JavaValue | undefi
   return items;
 }
 
-/** The entries of a map: `put` calls in order. */
+/**
+ * The entries of a map: the ones its constructor made, then `put` calls in
+ * order — a later `put` of the same key replaces the value in place.
+ */
 export function mapEntries(value: JavaValue | undefined): [JavaValue, JavaValue][] {
   if (!isJavaObject(value)) return [];
-  return value.calls
-    .filter((call) => call.method === 'put')
-    .map((call) => [call.args[0] ?? null, call.args[1] ?? null] as [JavaValue, JavaValue]);
+  const entries: [JavaValue, JavaValue][] = [...value.presetEntries];
+  for (const call of value.calls) {
+    if (call.method !== 'put') continue;
+    const key = call.args[0] ?? null;
+    const existing = entries.find(([entryKey]) => entryKey === key);
+    if (existing === undefined) entries.push([key, call.args[1] ?? null]);
+    else existing[1] = call.args[1] ?? null;
+  }
+  return entries;
 }
 
 // ── XML tree ───────────────────────────────────────────────────────────────
@@ -226,6 +240,7 @@ function newObject(fields: Partial<JavaObject> & { className: string }): JavaObj
     properties: new Map(),
     calls: [],
     presetElements: new Map(),
+    presetEntries: new Map(),
     fromGetter: fields.fromGetter ?? false,
   };
 }
@@ -412,6 +427,7 @@ class Decoder {
     if (isJavaObject(target)) {
       target.calls.push({ method, args });
       if (method === 'get' && args.length === 1 && typeof args[0] === 'number') return this.getIndex(target, args[0], id);
+      if (method === 'get' && args.length === 1 && typeof args[0] === 'string') return this.getEntry(target, args[0], id);
     }
     return null;
   }
@@ -463,6 +479,18 @@ class Decoder {
     return placeholder;
   }
 
+  /**
+   * `map.get(key)`: the value put before, else an entry the map held before
+   * the file touched it — a placeholder that later reads return.
+   */
+  private getEntry(target: JavaObject, key: string, id: string | undefined): JavaValue {
+    const put = mapEntries(target).find(([entryKey]) => entryKey === key);
+    if (put !== undefined) return put[1];
+    const placeholder = newObject({ className: id?.replace(/\d+$/, '') ?? 'unknown', id, fromGetter: true });
+    target.presetEntries.set(key, placeholder);
+    return placeholder;
+  }
+
   private setIndex(target: JavaValue | undefined, index: number, value: JavaValue): JavaValue {
     if (typeof target === 'object' && target !== null && (target as JavaArray).kind === 'array') {
       (target as JavaArray).items[index] = value;

packages/fls/src/systemSoftware.ts

@@ -0,0 +1,198 @@
+// The settings of a node's system software that the topology needs, read as
+// Java FILIUS holds them after loading: a switch's SSID and learning time, a
+// host's wireless SSID, a router's RIP switch, the manual routes, and the
+// firewall of a router or home router.
+// Java counterparts: filius.software.system.SwitchFirmware, Betriebssystem,
+// VermittlungsrechnerBetriebssystem, GatewayFirmware, InternetKnotenBetriebssystem,
+// filius.software.vermittlungsschicht.Weiterleitungstabelle,
+// filius.software.firewall.Firewall and FirewallRule.
+//
+// Checked against Java (corpus.java.json, `system`). DHCP, NAT, the modem,
+// file systems and applications are later layers.
+//
+// A router's firewall is one object its constructor makes and hangs in two
+// places: the installed applications and the configuration plug-ins of its
+// web server. XMLEncoder writes its settings wherever it meets it first —
+// in the corpus, under the web server's `konfig` plug-in. The decoder does
+// not know Java's constructors and sees a placeholder per path; they are
+// merged here.
+
+import { isJavaObject, isUnresolved, listItems, mapEntries, type JavaObject, type JavaValue } from './javabeans.js';
+import type { FlsNodeClass } from './topology.js';
+
+export interface FlsFirewallRule {
+  srcIP: string | null;
+  srcMask: string | null;
+  destIP: string | null;
+  destMask: string | null;
+  /** A port, or -1 for all. */
+  port: number;
+  /** -1 all, 1 ICMP, 6 TCP, 17 UDP. */
+  protocol: number;
+  /** 0 drop, 1 accept. */
+  action: number;
+}
+
+export interface FlsFirewall {
+  activated: boolean;
+  /** 0 drop, 1 accept. */
+  defaultPolicy: number;
+  dropICMP: boolean;
+  filterSYNSegmentsOnly: boolean;
+  filterUdp: boolean;
+  rules: FlsFirewallRule[];
+}
+
+export interface FlsSystemSoftware {
+  /**
+   * Switch: its SSID, undefined when the file has none (Java rolls one).
+   * Rechner, Notebook: the wireless network it joins, null for none.
+   */
+  ssid?: string | null | undefined;
+  /** Switch: how long it keeps a learned MAC address, in milliseconds. */
+  retentionTime?: number;
+  /** Vermittlungsrechner. */
+  ripEnabled?: boolean;
+  /** Every node with an IP stack: rows of destination, mask, gateway, interface address — as the file has them. */
+  manualRoutes?: (string | null)[][];
+  /** Vermittlungsrechner, Gateway. */
+  firewall?: FlsFirewall;
+}
+
+type Warn = (message: string) => void;
+
+const FIREWALL_CLASS = 'filius.software.firewall.Firewall';
+const WEB_SERVER_CLASS = 'filius.software.www.WebServer';
+
+export function readSystemSoftware(device: JavaObject, javaClass: FlsNodeClass, warn: Warn): FlsSystemSoftware {
+  const system = device.properties.get('systemSoftware');
+  const software = isJavaObject(system) ? system : undefined;
+  const value = (property: string) => software?.properties.get(property);
+  const result: FlsSystemSoftware = {};
+
+  switch (javaClass) {
+    case 'Switch':
+      result.ssid = optionalString(value('SSID'), 'SSID', warn);
+      result.retentionTime = integer(value('retentionTime'), 300_000, 'retentionTime', warn);
+      break;
+    case 'Rechner':
+    case 'Notebook':
+      result.ssid = optionalString(value('ssid'), 'ssid', warn) ?? null;
+      break;
+    case 'Vermittlungsrechner':
+      result.ripEnabled = boolean(value('ripEnabled'), false, 'ripEnabled', warn);
+      break;
+    case 'Gateway':
+    case 'Modem':
+      break;
+  }
+  if (javaClass !== 'Switch' && javaClass !== 'Modem') {
+    result.manualRoutes = manualRoutes(value('weiterleitungstabelle'), warn);
+  }
+  if (javaClass === 'Vermittlungsrechner' || javaClass === 'Gateway') {
+    result.firewall = firewall(software, warn);
+  }
+  return result;
+}
+
+function manualRoutes(table: JavaValue | undefined, warn: Warn): (string | null)[][] {
+  if (table === undefined || table === null) return [];
+  if (!isJavaObject(table)) {
+    warn(`weiterleitungstabelle is ${describe(table)}, ignored`);
+    return [];
+  }
+  return listItems(table.properties.get('manuelleTabelle')).map((row) =>
+    listItems(row).map((cell) => (typeof cell === 'string' || cell === null ? cell : null)),
+  );
+}
+
+/** Every object the file reaches the router's one firewall by. */
+function firewallObjects(software: JavaObject | undefined): JavaObject[] {
+  const found: JavaObject[] = [];
+  const applications = new Map(mapEntries(software?.properties.get('installierteAnwendungen')));
+  const installed = applications.get(FIREWALL_CLASS);
+  if (isJavaObject(installed)) found.push(installed);
+  const webServer = applications.get(WEB_SERVER_CLASS);
+  if (isJavaObject(webServer)) {
+    for (const [, plugin] of mapEntries(webServer.properties.get('plugins'))) {
+      const pluginFirewall = isJavaObject(plugin) ? plugin.properties.get('firewall') : undefined;
+      if (isJavaObject(pluginFirewall) && !found.includes(pluginFirewall)) found.push(pluginFirewall);
+    }
+  }
+  return found;
+}
+
+/** The firewall as the router's constructor leaves it (off, drop), then the file's settings. */
+function firewall(software: JavaObject | undefined, warn: Warn): FlsFirewall {
+  const properties = new Map<string, JavaValue>();
+  for (const object of firewallObjects(software)) {
+    for (const [property, value] of object.properties) {
+      if (properties.has(property) && properties.get(property) !== value) {
+        warn(`firewall: ${property} is set in two places, the later one is used`);
+      }
+      properties.set(property, value);
+    }
+  }
+  const at = (property: string) => properties.get(property);
+  // setAllowRelatedPackets is the old name of setFilterSYNSegmentsOnly.
+  const filterSyn = at('filterSYNSegmentsOnly') ?? at('allowRelatedPackets');
+  return {
+    activated: boolean(at('activated'), false, 'firewall activated', warn),
+    defaultPolicy: integer(at('defaultPolicy'), 0, 'firewall defaultPolicy', warn),
+    dropICMP: boolean(at('dropICMP'), false, 'firewall dropICMP', warn),
+    filterSYNSegmentsOnly: boolean(filterSyn, true, 'firewall filterSYNSegmentsOnly', warn),
+    filterUdp: boolean(at('filterUdp'), true, 'firewall filterUdp', warn),
+    rules: listItems(at('ruleset')).flatMap((rule) => (isJavaObject(rule) ? [firewallRule(rule, warn)] : [])),
+  };
+}
+
+/**
+ * FirewallRule: public fields set one by one (`getField(name).set`), or the
+ * seven-argument constructor. Defaults: all addresses empty, all ports, TCP,
+ * drop.
+ */
+function firewallRule(rule: JavaObject, warn: Warn): FlsFirewallRule {
+  const [srcIP, srcMask, destIP, destMask, port, protocol, action] = rule.args.length === 7 ? rule.args : [];
+  const field = (name: string, fromConstructor: JavaValue | undefined) => rule.properties.get(name) ?? fromConstructor;
+  const text = (name: string, fromConstructor: JavaValue | undefined) => {
+    const value = field(name, fromConstructor) ?? '';
+    if (typeof value === 'string' || value === null) return value;
+    warn(`firewall rule: ${name} is ${describe(value)}, used ""`);
+    return '';
+  };
+  return {
+    srcIP: text('srcIP', srcIP),
+    srcMask: text('srcMask', srcMask),
+    destIP: text('destIP', destIP),
+    destMask: text('destMask', destMask),
+    port: integer(field('port', port), -1, 'firewall rule port', warn),
+    protocol: integer(field('protocol', protocol), 6, 'firewall rule protocol', warn),
+    action: integer(field('action', action), 0, 'firewall rule action', warn),
+  };
+}
+
+function optionalString(value: JavaValue | undefined, name: string, warn: Warn): string | null | undefined {
+  if (value === undefined || value === null || typeof value === 'string') return value;
+  warn(`${name} is ${describe(value)}, ignored`);
+  return undefined;
+}
+
+function boolean(value: JavaValue | undefined, fallback: boolean, name: string, warn: Warn): boolean {
+  if (value === undefined) return fallback;
+  if (typeof value === 'boolean') return value;
+  warn(`${name} is ${describe(value)}, used ${fallback}`);
+  return fallback;
+}
+
+function integer(value: JavaValue | undefined, fallback: number, name: string, warn: Warn): number {
+  if (value === undefined) return fallback;
+  if (typeof value === 'number' && Number.isInteger(value)) return value;
+  warn(`${name} is ${describe(value)}, used ${fallback}`);
+  return fallback;
+}
+
+function describe(value: JavaValue): string {
+  if (isUnresolved(value)) return `unresolved (${value.reason})`;
+  if (isJavaObject(value)) return `an object of ${value.className}`;
+  return typeof value === 'bigint' ? `${value}` : JSON.stringify(value);
+}

packages/fls/src/topology.ts

@@ -1,8 +1,8 @@
 // The network drawn in a .fls file — devices, cables, documentation items —
 // read from the decoded JavaBeans graph (javabeans.ts) the way Java FILIUS
-// loads it (SzenarioVerwaltung.netzwerkLaden). Only the topology: system
-// software, file systems and applications are later layers, which start
-// from `FlsNode.source`.
+// loads it (SzenarioVerwaltung.netzwerkLaden), with the system software
+// settings the topology needs (systemSoftware.ts). File systems and
+// applications are later layers, which start from `FlsNode.source`.
 //
 // The result is Java's view, indexed like Java's lists, and is checked
 // against Java itself (corpus.java.json). The editor model (node kinds, UUIDs,
@@ -19,6 +19,7 @@
 
 import { isJavaObject, isUnresolved, listItems, simpleClassName, type JavaObject, type JavaValue } from './javabeans.js';
 import { javaIpCheck } from './javaIp.js';
+import { readSystemSoftware, type FlsSystemSoftware } from './systemSoftware.js';
 
 export type FlsNodeClass = 'Rechner' | 'Notebook' | 'Switch' | 'Vermittlungsrechner' | 'Gateway' | 'Modem';
 
@@ -44,6 +45,8 @@ export interface FlsNode {
   interfaces: FlsInterface[];
   /** Interfaces, or the ports of a Switch or Modem. */
   portCount: number;
+  /** SSIDs, routes, RIP, firewall (systemSoftware.ts). */
+  system: FlsSystemSoftware;
   /** The node's JavaBean (`filius.hardware.knoten.*`), for the software layers. */
   source: JavaObject;
 }
@@ -191,6 +194,9 @@ class Reader {
       useMacAsName: info.host && this.booleanProperty(device, 'useMACAsName', `node ${itemIndex + 1}`),
       interfaces: [],
       portCount: 0,
+      system: readSystemSoftware(device, simpleName, (message) =>
+        this.warnings.push(`node ${itemIndex + 1}: ${message}`),
+      ),
       source: device,
     };
 

packages/fls/test/importProject.test.ts

@@ -214,8 +214,9 @@ function flsNode(javaClass: FlsNode['javaClass'], fields: Partial<FlsNode> = {})
     useMacAsName: false,
     interfaces: [],
     portCount: 0,
+    system: {},
     source: { kind: 'object', className: javaClass, id: undefined, args: [], staticField: undefined,
-      factoryMethod: undefined, properties: new Map(), calls: [], presetElements: new Map(), fromGetter: false },
+      factoryMethod: undefined, properties: new Map(), calls: [], presetElements: new Map(), presetEntries: new Map(), fromGetter: false },
     ...fields,
   };
 }

packages/fls/test/javabeans.test.ts

@@ -186,6 +186,33 @@ describe('XMLDecoder rules', () => {
     expect(listItems(list)).toHaveLength(3);
   });
 
+  it("keeps the entries a constructor made in a map, reached by get(key), and shares them", () => {
+    // A router's operating system installs its web server in the constructor;
+    // the file reaches it through the map and changes it.
+    const [system] = decodeJavaBeans(
+      doc(`<object class="filius.software.system.VermittlungsrechnerBetriebssystem">
+             <void id="HashMap0" property="installierteAnwendungen">
+               <void id="WebServer0" method="get"><string>filius.software.www.WebServer</string>
+                 <void property="aktiv"><boolean>true</boolean></void>
+               </void>
+               <void method="get"><string>filius.software.www.WebServer</string>
+                 <void property="port"><int>8080</int></void>
+               </void>
+               <void method="put"><string>extra</string><int>1</int></void>
+             </void>
+           </object>`),
+    );
+
+    const entries = mapEntries(object(system).properties.get('installierteAnwendungen'));
+    expect(entries.map(([key]) => key)).toEqual(['filius.software.www.WebServer', 'extra']);
+    const server = object(entries[0]![1]);
+    expect(server).toMatchObject({ className: 'WebServer', id: 'WebServer0', fromGetter: true });
+    expect([...server.properties]).toEqual([
+      ['aktiv', true],
+      ['port', 8080],
+    ]);
+  });
+
   it('replays add at an index and set by index in order', () => {
     const [list] = decodeJavaBeans(
       doc(`<object class="java.util.ArrayList">

packages/fls/test/topology.test.ts

@@ -50,6 +50,26 @@ function asJavaView(topology: FlsTopology, javaBounds: (number[] | null)[]) {
         node.javaClass === 'Switch' || node.javaClass === 'Modem'
           ? Array.from({ length: node.portCount }, () => ({}))
           : node.interfaces.map((nic) => ({ ...nic, mac: nic.mac ?? null })),
+      system: {
+        ...node.system,
+        ...('ssid' in node.system ? { ssid: node.system.ssid ?? null } : {}),
+        ...(node.system.firewall === undefined
+          ? {}
+          : {
+              firewall: {
+                ...node.system.firewall,
+                rules: node.system.firewall.rules.map((rule) => [
+                  rule.srcIP,
+                  rule.srcMask,
+                  rule.destIP,
+                  rule.destMask,
+                  rule.port,
+                  rule.protocol,
+                  rule.action,
+                ]),
+              },
+            }),
+      },
     })),
     cables: topology.links.map((link) => ({
       ends: link.ends.map((end) => [end.node, end.port]),
@@ -177,6 +197,44 @@ describe('readTopology rules', () => {
     expect(wrongFirst.nodes).toEqual([]);
   });
 
+  it("reads a router's firewall wherever the file reaches it, with Java's defaults for what it leaves out", () => {
+    // Settings under the installed application and under the web server's
+    // plug-in belong to the one firewall the constructor made.
+    const { nodes } = topologyOf(`<object class="java.util.LinkedList">${nodeItem(`<object class="filius.hardware.knoten.Vermittlungsrechner">
+        <void property="systemSoftware"><void property="installierteAnwendungen">
+          <void method="get"><string>filius.software.firewall.Firewall</string>
+            <void property="allowRelatedPackets"><boolean>false</boolean></void>
+            <void property="ruleset">
+              <void method="add"><object class="filius.software.firewall.FirewallRule" id="FirewallRule0">
+                <void class="filius.software.firewall.FirewallRule" method="getField"><string>srcIP</string>
+                  <void method="set"><object idref="FirewallRule0"/><string>10.0.0.0</string></void></void>
+              </object></void>
+              <void method="add"><object class="filius.software.firewall.FirewallRule">
+                <string>1.1.1.1</string><string>255.255.255.255</string><string></string><string></string>
+                <int>53</int><short>17</short><short>1</short>
+              </object></void>
+            </void>
+          </void>
+          <void method="get"><string>filius.software.www.WebServer</string>
+            <void property="plugins"><void method="get"><string>konfig</string>
+              <void property="firewall"><void property="activated"><boolean>true</boolean></void></void>
+            </void></void>
+          </void>
+        </void></void></object>`)}</object>`);
+
+    expect(nodes[0]!.system.firewall).toEqual({
+      activated: true,
+      defaultPolicy: 0,
+      dropICMP: false,
+      filterSYNSegmentsOnly: false,
+      filterUdp: true,
+      rules: [
+        { srcIP: '10.0.0.0', srcMask: '', destIP: '', destMask: '', port: -1, protocol: 6, action: 0 },
+        { srcIP: '1.1.1.1', srcMask: '255.255.255.255', destIP: '', destMask: '', port: 53, protocol: 17, action: 1 },
+      ],
+    });
+  });
+
   it("reads colors as Java's constructors do and keeps an invalid one unset", () => {
     const colors = ['<int>16711935</int>', '<int>1</int><int>2</int><int>3</int>', '<int>1</int><int>2</int><int>300</int><int>4</int>'];
     const { documentation, warnings } = topologyOf(`<object class="java.util.LinkedList"/><object class="java.util.LinkedList"/>