feat: ePMP firmware extraction + ePMP3000 NetSNMP-quirk detection

ePMP devices were not reporting firmware_version because the YAML's
cambiumCurrentuImageVersion.0 OID returns empty on ePMP3000 firmware.
Add detect_version/1 to the Epmp vendor module with two-OID fallback:
cambiumCurrentSWInfo.0 (verbose, ePMP3000-friendly) → cambiumCurrentuImageVersion.0
(short, ePMP1000/2000), with a regex to extract the version triplet
from whatever the device returns.

ePMP3000 also has a sysObjectID quirk where some firmware reports the
generic NetSNMP-on-Linux ID (.1.3.6.1.4.1.8072.3.2.10) instead of the
Cambium enterprise OID, causing devices to misclassify as the linux
profile. Add a second discovery block to the epmp profile that matches
NetSNMP-OID + PREEMPT_RT armv7l kernel signature + a confirming snmpget
against the Cambium ePMP MIB tree, so detection runs in pass-2
(conditional non-generic) before linux falls through in pass-3.

lib/towerops/snmp/profiles/vendors/epmp.ex

@@ -21,6 +21,15 @@ defmodule Towerops.Snmp.Profiles.Vendors.Epmp do
   # cambiumSubModeType = { cambiumGeneralStatus 33 } = 1.3.6.1.4.1.17713.21.1.1.33
   @sub_mode_oid "1.3.6.1.4.1.17713.21.1.1.33.0"
 
+  # OIDs for firmware version detection (from CAMBIUM-PMP80211-MIB)
+  # cambiumCurrentSWInfo = { cambiumGeneralStatus 1 } - verbose software info string (1..128 chars)
+  @sw_info_oid "1.3.6.1.4.1.17713.21.1.1.1.0"
+  # cambiumCurrentuImageVersion = { cambiumGeneralStatus 17 } - short version string (0..20 chars)
+  @image_version_oid "1.3.6.1.4.1.17713.21.1.1.17.0"
+
+  # Match a typical version triplet/quad like "4.7.1.1", "4.7.1-RC4", etc.
+  @version_regex ~r/(\d+\.\d+(?:\.\d+)*(?:[-_][A-Za-z0-9]+)?)/
+
   @impl true
   def profile_names, do: ["epmp"]
 
@@ -42,6 +51,45 @@ defmodule Towerops.Snmp.Profiles.Vendors.Epmp do
     end
   end
 
+  @doc """
+  Detect firmware version with a two-OID fallback strategy.
+
+  Tries `cambiumCurrentSWInfo.0` first (verbose, 128-char string — more
+  reliably populated on ePMP3000 firmware images), then falls back to
+  `cambiumCurrentuImageVersion.0` (short 20-char string used by ePMP1000/2000).
+
+  Extracts a version-looking substring (e.g. `4.7.1.1`) from whatever the
+  device returns; if no version pattern matches, returns the trimmed raw
+  string. Returns `nil` when both OIDs error or return empty.
+  """
+  def detect_version(client_opts) do
+    fetch_version(@sw_info_oid, client_opts) ||
+      fetch_version(@image_version_oid, client_opts)
+  end
+
+  defp fetch_version(oid, client_opts) do
+    case Client.get(client_opts, oid) do
+      {:ok, value} when is_binary(value) -> normalize_version(value)
+      _ -> nil
+    end
+  end
+
+  defp normalize_version(value) do
+    trimmed = String.trim(value)
+
+    cond do
+      trimmed == "" ->
+        nil
+
+      match = Regex.run(@version_regex, trimmed) ->
+        [_, version] = match
+        version
+
+      true ->
+        trimmed
+    end
+  end
+
   @impl true
   def discover_wireless_sensors(client_opts) do
     Vendor.fetch_sensors(wireless_oid_defs(), client_opts)

priv/profiles/os_detection/epmp.yaml

@@ -9,3 +9,15 @@ discovery:
     -
         sysObjectID:
             - .1.3.6.1.4.1.17713.21
+    -
+        # ePMP3000 firmware quirk: some images report sysObjectID as the
+        # generic NetSNMP-on-Linux ID (.1.3.6.1.4.1.8072.3.2.10) instead of
+        # the Cambium enterprise OID. Detect by matching the PREEMPT_RT
+        # armv7l kernel signature and confirming the Cambium ePMP MIB tree
+        # responds. Both must pass before claiming the device as ePMP.
+        sysObjectID: .1.3.6.1.4.1.8072.3.2.10
+        sysDescr_regex: '/PREEMPT RT.+armv7l/'
+        snmpget:
+            oid: CAMBIUM-PMP80211-MIB::cambiumCurrentSWInfo.0
+            op: '!='
+            value: false

test/towerops/snmp/profiles/vendors/epmp_test.exs

@@ -58,6 +58,71 @@ defmodule Towerops.Snmp.Profiles.Vendors.EpmpTest do
     end
   end
 
+  describe "detect_version/1" do
+    @sw_info_oid "1.3.6.1.4.1.17713.21.1.1.1.0"
+    @image_version_oid "1.3.6.1.4.1.17713.21.1.1.17.0"
+
+    test "extracts version from cambiumCurrentSWInfo verbose string" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ ->
+        {:ok, "ePMP-AP_Latest 4.7.1.1"}
+      end)
+
+      assert Epmp.detect_version(@client_opts) == "4.7.1.1"
+    end
+
+    test "returns plain version string from cambiumCurrentSWInfo" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ ->
+        {:ok, "4.7.1.1"}
+      end)
+
+      assert Epmp.detect_version(@client_opts) == "4.7.1.1"
+    end
+
+    test "preserves -RC suffix in version" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ ->
+        {:ok, "4.7.1-RC4"}
+      end)
+
+      assert Epmp.detect_version(@client_opts) == "4.7.1-RC4"
+    end
+
+    test "falls back to cambiumCurrentuImageVersion when SW info errors" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ -> {:error, :no_such_object} end)
+      expect(SnmpMock, :get, fn _, @image_version_oid, _ -> {:ok, "4.6.2"} end)
+
+      assert Epmp.detect_version(@client_opts) == "4.6.2"
+    end
+
+    test "falls back when SW info returns empty string" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ -> {:ok, ""} end)
+      expect(SnmpMock, :get, fn _, @image_version_oid, _ -> {:ok, "4.6.2"} end)
+
+      assert Epmp.detect_version(@client_opts) == "4.6.2"
+    end
+
+    test "returns nil when both OIDs fail" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ -> {:error, :timeout} end)
+      expect(SnmpMock, :get, fn _, @image_version_oid, _ -> {:error, :timeout} end)
+
+      assert Epmp.detect_version(@client_opts) == nil
+    end
+
+    test "returns nil when both OIDs return empty" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ -> {:ok, ""} end)
+      expect(SnmpMock, :get, fn _, @image_version_oid, _ -> {:ok, ""} end)
+
+      assert Epmp.detect_version(@client_opts) == nil
+    end
+
+    test "trims whitespace from raw value when no version pattern matches" do
+      expect(SnmpMock, :get, fn _, @sw_info_oid, _ ->
+        {:ok, "  unknown-build  "}
+      end)
+
+      assert Epmp.detect_version(@client_opts) == "unknown-build"
+    end
+  end
+
   describe "wireless_oid_defs/0" do
     test "returns list of sensor definitions" do
       defs = Epmp.wireless_oid_defs()