feat: report what listens, and which OPNsense service it is

get_listening_sockets reads /api/diagnostics/interface/get_socket_statistics:
netstat's sockets with sockstat's user, command and PID, collected by
configd as root, so no SSH is needed. A listening socket is one without a
peer (*:*); "*" is the any-address of the socket's family.

Which service: the socket's unit is a name of the firewall's own service
list, so netOrk can match it to the service. The command (cut to ten
characters by FreeBSD) matches a service name, the start of one, or one
of the daemons whose service is called otherwise (sshd is openssh, the
FRR daemons are frr, kea-ctrl-agent is kea-dhcp). lighttpd is the web UI,
or the captive portal when it runs as www. WireGuard's sockets belong to
the kernel and are told by the listen ports of /api/wireguard/service/show.

The fixture is a real OPNsense 26.7.5 firewall's answer, cut down, with
documentation addresses. For netOrk#673.

napalm_opnsense/opnsense.py

@@ -53,8 +53,10 @@ import requests
 from requests.exceptions import RequestException
 
 from napalm_device_types import FingerprintRule, FirewallDriver
+from napalm_device_types.models import ListeningSocketsDict
 from napalm.base.exceptions import ConnectionException, ConnectionClosedException, MergeConfigException
 
+from napalm_opnsense.listening import parse_socket_statistics, wireguard_listen_ports
 from napalm_opnsense.ping_mixin import OPNsensePingMixin
 from napalm_opnsense.port_forwards import alias_index, port_forwards, wan_interfaces
 
@@ -1789,6 +1791,26 @@ class OPNsenseDriver(OPNsensePingMixin, FirewallDriver):
             })
         return sorted(result, key=lambda x: x["name"].lower())
 
+    def get_listening_sockets(self) -> ListeningSocketsDict:
+        """Every listening TCP and bound UDP socket, with the OPNsense service behind it.
+
+        Read from ``/api/diagnostics/interface/get_socket_statistics``, which
+        configd collects as root, so every socket names its process where it has
+        one (``attributed``). Which service: :mod:`napalm_opnsense.listening`.
+        """
+        statistics = self._get("/api/diagnostics/interface/get_socket_statistics")
+        services = [service["name"] for service in self.get_services()]
+        try:
+            wireguard = wireguard_listen_ports(self._get("/api/wireguard/service/show"))
+        except Exception as exc:
+            # No WireGuard here: its kernel sockets stay nobody's.
+            logger.debug("WireGuard listen ports not read: %s", exc)
+            wireguard = set()
+        return {
+            "attributed": True,
+            "sockets": parse_socket_statistics(statistics, services, wireguard),
+        }
+
     def manage_service(self, name: str, action: str) -> dict[str, Any]:
         """Execute a lifecycle action on an OPNsense service.