feat(firewall): report the gateway a filter rule policy-routes to

get_firewall_rules read searchRule but dropped the rule's gateway. A pass
rule with a gateway hands what it matches to that gateway, local
destinations included, so it does not reach a host on another internal
network. Without the field a caller judging reachability reads a rule meant
for internet traffic as a hole into every server: on the first real box,
"pass UDP IOT -> any" via WAN_GW made 61 hosts look reachable from the IoT
segment (netOrk #575).

The rule dict gains "gateway", the gateway's name or "". It is an extra
field like floating and interface_label; the generic diff compares a fixed
field list and ignores it.

napalm_opnsense/opnsense.py

@@ -2444,6 +2444,10 @@ class OPNsenseDriver(OPNsensePingMixin, FirewallDriver):
         * ``floating``          — bool, rule applies across all interfaces
         * ``interface_label``   — human-readable interface description
         * ``is_group``          — bool, interface is an interface group
+        * ``gateway``           — the gateway a pass rule policy-routes to, or
+          ``""``. Such a rule sends what it matches to that gateway, local
+          destinations included, so it does not reach a host on another
+          internal network.
         """
         try:
             resp = self._get("/api/firewall/filter/searchRule?current=1&rowCount=-1")
@@ -2508,6 +2512,7 @@ class OPNsenseDriver(OPNsensePingMixin, FirewallDriver):
                 "log":              str(row.get("log", "0")) == "1",
                 "enabled":          str(row.get("enabled", "1")) == "1",
                 "category":         category,
+                "gateway":          row.get("gateway", "") or "",
             })
 
         return sorted(result, key=lambda x: (x["floating"], x["is_group"], x["interface"], x["sequence"]))

tests/unit/test_firewall_rules.py

@@ -0,0 +1,78 @@
+"""Filter rules as ``get_firewall_rules`` reports them.
+
+A pass rule with a gateway is policy routing: OPNsense hands what it matches to
+that gateway, local destinations included. A caller judging which network can
+reach which host has to know that, or a rule meant for internet traffic reads
+as a hole into every server (netOrk #575: on the first real box, "pass UDP
+IOT -> any" via WAN_GW made 61 hosts look reachable from the IoT segment).
+
+The row shape follows that box's ``/api/firewall/filter/searchRule``.
+"""
+
+from __future__ import annotations
+
+from unittest.mock import patch
+
+import pytest
+
+from napalm_opnsense.opnsense import OPNsenseDriver
+
+
+@pytest.fixture
+def driver():
+    with patch("napalm_opnsense.opnsense.requests.Session"):
+        yield OPNsenseDriver(
+            hostname="opnsense.example.com",
+            username="api_key",
+            password="api_secret",
+            optional_args={"verify": False},
+        )
+
+
+def _row(**over) -> dict:
+    """One rule row as the API returns it; booleans are "0"/"1" strings."""
+    row = {
+        "uuid": "u1",
+        "sequence": "1",
+        "action": "pass",
+        "quick": "1",
+        "interface": "opt3",
+        "%interface": "IOT",
+        "direction": "in",
+        "ipprotocol": "inet",
+        "protocol": "UDP",
+        "%source_net": "HOME_OFFICE_IOT_NET",
+        "%destination_net": "any",
+        "destination_port": "",
+        "description": "reolink_udp_long_state_timeout",
+        "enabled": "1",
+        "gateway": "WAN_GW",
+    }
+    row.update(over)
+    return row
+
+
+def _rules(driver, *rows):
+    def fake_get(path):
+        return {"rows": list(rows)} if "searchRule" in path else {"rows": []}
+
+    with patch.object(driver, "_get", side_effect=fake_get):
+        return driver.get_firewall_rules()
+
+
+def test_a_policy_routed_rule_reports_its_gateway(driver):
+    [rule] = _rules(driver, _row(gateway="WAN_GW"))
+    assert rule["gateway"] == "WAN_GW"
+
+
+def test_a_rule_that_routes_normally_reports_no_gateway(driver):
+    [rule] = _rules(driver, _row(gateway=""))
+    assert rule["gateway"] == ""
+
+
+def test_a_row_without_the_field_reports_no_gateway(driver):
+    # Older firmware, or a rule type that never carries one.
+    row = _row()
+    del row["gateway"]
+    [rule] = _rules(driver, row)
+    assert rule["gateway"] == ""