feat: read the host's listening sockets through napalm-device-types

LinuxDriver mixes in ListeningSocketsMixin (napalm-device-types 2.4.0) and
supplies its transport: privileged readings go through _run_privileged --
as they are for a root login, through sudo with a password, sudo -n
without one -- and the rest through _send. The command arrives as one
sh -c argument, so sudo covers the whole script; when sudo refuses, the
mixin reads again without it.

OpenMediaVault and QNAP QTS inherit it; a host without ss raises
ListeningSocketsUnavailable.

For netOrk#658.

napalm_linux/linux.py

@@ -37,6 +37,7 @@ from napalm_device_types import (
     FingerprintRule,
     HostStatusMixin,
     KernelFactsMixin,
+    ListeningSocketsMixin,
     OSDriver,
     SystemdServicesMixin,
     SystemdUnavailable,
@@ -214,7 +215,9 @@ def _short_image_id(raw: str) -> str:
     return raw.strip().removeprefix("sha256:")[:12]
 
 
-class LinuxDriver(KernelFactsMixin, SystemdServicesMixin, HostStatusMixin, OSDriver):
+class LinuxDriver(
+    KernelFactsMixin, ListeningSocketsMixin, SystemdServicesMixin, HostStatusMixin, OSDriver
+):
     """NAPALM driver for generic Linux systems.
 
     Connects via SSH (netmiko ``linux`` device type) and auto-detects the
@@ -969,6 +972,19 @@ class LinuxDriver(KernelFactsMixin, SystemdServicesMixin, HostStatusMixin, OSDri
         """The transport for ``KernelFactsMixin.get_kernel_facts``: read-only, no sudo."""
         return self._send(command, read_timeout=60)
 
+    # ------------------------------------------------------------------
+    # ListeningSocketsMixin – the transport for get_listening_sockets
+    # ------------------------------------------------------------------
+
+    def _run_listening_sockets_command(self, command: str, *, privileged: bool) -> str:
+        """The transport for ``ListeningSocketsMixin.get_listening_sockets``.
+
+        Read-only either way; root only so that ``ss`` names every process.
+        """
+        if privileged:
+            return self._run_privileged(command, 60)
+        return self._send(command, read_timeout=60)
+
     # ------------------------------------------------------------------
     # OSDriver – package management
     # ------------------------------------------------------------------