Fix FBP negotiated packet version handling

docs/test-harness-design.md

@@ -445,13 +445,11 @@ test venv; otherwise a temporary venv is used for the scenario.
   with unrelated HBP-to-HBP routing.
 - Version-negotiation bugs visible over UDP: BCVE downgrade, unsupported version
   or invalid hash must not mutate the configured outbound behavior, and v4
-  packet fixtures characterize the historical v4 metadata layout.
-- Known protocol-version issues can be carried as expected-failure black-box
-  tests until runtime behavior is changed: unsupported embedded `DMRE` versions
-  are currently not rejected, and the v4 send layout currently carries the
-  module default version byte instead of the configured `PROTO_VER` value. v4
-  is historical/deprecation context, not a desired long-term compatibility
-  target.
+  packet fixtures characterize the historical v4 metadata layout. Configured
+  v4 outbound `DMRE` packets must carry the negotiated session version byte,
+  while BCVE advertises the local maximum supported version so peers can
+  upgrade. v4 is historical/deprecation context, not a desired long-term
+  compatibility target.
 - Protocol-refusal bugs visible over UDP: signed v1 OBP packets on a
   v5-configured link should produce BCVE and should not leak to HBP targets.
   v1 itself remains supported as an open OBP interop protocol, especially for
@@ -638,8 +636,9 @@ Assertions should be grouped by intent:
   and valid BCST STUN blocks OpenBridge traffic in both directions.
 - UDP black-box FBP version tests verify that BCVE downgrade, unsupported
   version and invalid hash do not change outbound packet version, and that
-  historical v4 packet fixtures currently route using the older metadata layout.
-  This v4 coverage is characterization/deprecation context.
+  historical v4 packet fixtures route using the older metadata layout with the
+  negotiated session version byte. This v4 coverage is
+  characterization/deprecation context.
 - UDP black-box OBP-v1 refusal tests verify that a signed v1 packet received on
   a v5-configured link receives BCVE and does not route onward.
 

docs/testing.md

@@ -215,8 +215,9 @@ routing in both directions, startup acceptance of slot/route-specific timer
 directives, FBP keepalive/version control setup, BCKA gating of enhanced
 HBP-to-FBP forwarding, BCSQ source-quench suppression of HBP-to-FBP forwarding,
 rejection of invalid BCSQ, BCVE downgrade/unsupported/invalid-version handling,
-current FBP v5 packet handling, historical FBP v4 characterization, and signed
-v1 OBP packet refusal on a v5-configured link. v1 remains an important open OBP
+current FBP v5 packet handling, historical FBP v4 characterization including
+negotiated outbound packet version bytes, and signed v1 OBP packet refusal on a
+v5-configured link. v1 remains an important open OBP
 interop protocol for external network bridge instances, primarily through
 `bridge.py`; the `bridge_master.py` UDP test here only verifies that a
 v5-configured FBP link refuses v1 traffic. They also cover rejection of FBP
@@ -238,12 +239,11 @@ stale FBP timestamps and max-hop FBP packets; these must not leak traffic to HBP
 targets, and stale/max-hop FBP packets must produce a source-quench response.
 Selected malformed packet tests also assert subprocess warning logs.
 
-Two UDP tests are marked as expected failures because they document current
-protocol-version issues rather than fixed behavior: unsupported embedded `DMRE`
-packet versions are not yet rejected, and the historical v4 send layout
-currently carries the module default version byte instead of the configured
-`PROTO_VER` value. v4 is characterization/deprecation context, not a long-term
-protocol contract.
+Protocol-version regression coverage verifies unsupported embedded `DMRE`
+packet versions are rejected without poisoning the session version, and the
+historical v4 send layout carries the negotiated session version byte. BCVE
+advertises the local maximum supported version. v4 is
+characterization/deprecation context, not a long-term protocol contract.
 
 UDP integration tests are opt-in:
 

docs/v1x-codex-changelog.md

@@ -78,6 +78,9 @@
   peer being quenched, including dial-a-TG reflector TGs.
 - Made STUN/BCST handling consistent as a broad FBP traffic gate.
 - Preserved protocol-version-sensitive FBP/OBP metadata layout.
+- Fixed outbound FBP `DMRE` version bytes to use the negotiated OpenBridge
+  session version rather than the module default version constant. BCVE remains
+  an advertisement of the local maximum supported version.
 - Added tests for FBP keepalive gating, wrong network ID, bad hashes, stale
   timestamps, max-hop handling, v4 characterization and v1 refusal on v5 links.
 

hblink.py

@@ -184,7 +184,7 @@ class OPENBRIDGE(DatagramProtocol):
         if _packet[:3] == DMR and self._config['TARGET_IP']:
             
             if 'VER' in self._config and self._config['VER'] > 4:
-                _ver = VER.to_bytes(1,'big')
+                _ver = self._config['VER'].to_bytes(1,'big')
                 _packet = b''.join([DMRE,_packet[4:11], self._CONFIG['GLOBAL']['SERVER_ID'],_packet[15:],_ber,_rssi,_ver,time_ns().to_bytes(8,'big'), _source_server, _source_rptr, _hops])
                 _h = blake2b(key=self._config['PASSPHRASE'], digest_size=16)
                 _h.update(_packet)
@@ -193,7 +193,7 @@ class OPENBRIDGE(DatagramProtocol):
                 self.transport.write(_packet, (self._config['TARGET_IP'], self._config['TARGET_PORT']))
 
             elif 'VER' in self._config and self._config['VER'] == 4:
-                _ver = VER.to_bytes(1,'big')
+                _ver = self._config['VER'].to_bytes(1,'big')
                 _packet = b''.join([DMRE,_packet[4:11], self._CONFIG['GLOBAL']['SERVER_ID'],_packet[15:],_ber,_rssi,_ver,time_ns().to_bytes(8,'big'), _source_server, _hops])
                 _h = blake2b(key=self._config['PASSPHRASE'], digest_size=16)
                 _h.update(_packet)

tests/test_deterministic_harness.py

@@ -2026,6 +2026,58 @@ DEFAULT_DIAL_TS2: 92
             self.assertEqual(config["SYSTEMS"]["OBP-1"]["VER"], 5)
             self.assertEqual(scenario.capture.for_system("OBP-1"), [])
 
+    def test_openbridge_send_system_uses_configured_v4_packet_version(self):
+        config = minimal_config(())
+        add_openbridge_system(config, "OBP-1", network_id=3001)
+        config["SYSTEMS"]["OBP-1"]["VER"] = 4
+        config["SYSTEMS"]["OBP-1"]["TARGET_PORT"] = 62031
+
+        with DeterministicScenario(config=config) as scenario:
+            system = scenario.bm.systems["OBP-1"]
+
+            scenario.bm.OPENBRIDGE.send_system(system, PacketSpec(peer_id=3001).data()[:53])
+
+            packet, sockaddr = scenario.transports["OBP-1"].writes[-1]
+
+        self.assertEqual(sockaddr, ("127.0.0.1", 62031))
+        self.assertEqual(packet[:4], b"DMRE")
+        self.assertEqual(len(packet), 85)
+        self.assertEqual(packet[55], 4)
+
+    def test_openbridge_send_system_uses_configured_v5_packet_version(self):
+        config = minimal_config(())
+        add_openbridge_system(config, "OBP-1", network_id=3001)
+        config["SYSTEMS"]["OBP-1"]["VER"] = 5
+        config["SYSTEMS"]["OBP-1"]["TARGET_PORT"] = 62031
+
+        with DeterministicScenario(config=config) as scenario:
+            system = scenario.bm.systems["OBP-1"]
+
+            scenario.bm.OPENBRIDGE.send_system(system, PacketSpec(peer_id=3001).data()[:53])
+
+            packet, sockaddr = scenario.transports["OBP-1"].writes[-1]
+
+        self.assertEqual(sockaddr, ("127.0.0.1", 62031))
+        self.assertEqual(packet[:4], b"DMRE")
+        self.assertEqual(len(packet), 89)
+        self.assertEqual(packet[55], 5)
+
+    def test_openbridge_send_bcve_advertises_max_supported_version(self):
+        config = minimal_config(())
+        add_openbridge_system(config, "OBP-1", network_id=3001)
+        config["SYSTEMS"]["OBP-1"]["VER"] = 4
+        config["SYSTEMS"]["OBP-1"]["ENHANCED_OBP"] = True
+        config["SYSTEMS"]["OBP-1"]["TARGET_PORT"] = 62031
+
+        with DeterministicScenario(config=config) as scenario:
+            scenario.bm.systems["OBP-1"].send_bcve()
+
+            packet, sockaddr = scenario.transports["OBP-1"].writes[-1]
+
+        self.assertEqual(sockaddr, ("127.0.0.1", 62031))
+        self.assertEqual(packet[:4], b"BCVE")
+        self.assertEqual(packet[4], 5)
+
     def test_hbp_master_parser_discards_truncated_dmrd_from_connected_peer(self):
         config = minimal_config(("MASTER-A",))
 

tests/test_udp_blackbox_harness.py

@@ -980,7 +980,6 @@ class UdpBlackBoxHarnessTest(unittest.TestCase):
         self.assertEqual(len(captured.packet), 85)
         self.assertEqual(captured.fields["source_rptr"], b"\x00\x00\x00\x00")
 
-    @unittest.expectedFailure
     def test_fbp_configured_proto_v4_outbound_packet_carries_v4_version_byte(self):
         require_udp_integration_enabled()