Use UTIL.AssocFindDevice to determine alignment and add new structs

Author: puddly

tests/conftest.py

@@ -738,6 +738,10 @@ def update_channel():
     def zdo_route_check(self, request):
         return c.ZDO.ExtRouteChk.Rsp(Status=c.zdo.RoutingStatus.SUCCESS)
 
+    @reply_to(c.UTIL.AssocFindDevice.Req(Index=0))
+    def assoc_find_dev_responder(self, req):
+        return req.Rsp(Device=t.Bytes(b"\xFF" * (36 if self.align_structs else 28)))
+
 
 class BaseZStack1CC2531(BaseZStackDevice):
     align_structs = False

tests/tools/test_nvram.py

@@ -115,11 +115,6 @@ async def test_nvram_write(device, make_znp_server, tmp_path, mocker):
     # This already exists
     znp_server._nvram[ExNvIds.LEGACY][OsalNvIds.HAS_CONFIGURED_ZSTACK3] = b"\xBB"
 
-    # XXX: empty NVRAM breaks current alignment autodetection method (NWKKEY is missing)
-    async def replacement(self, *args, **kwargs):
-        self.align_structs = znp_server.align_structs
-
-    mocker.patch("zigpy_znp.nvram.NVRAMHelper.determine_alignment", new=replacement)
     await nvram_write([znp_server._port_path, "-i", str(backup_file)])
 
     nvram_obj = dump_nvram(znp_server)

zigpy_znp/commands/util.py

@@ -399,7 +399,8 @@ class UTIL(t.CommandsBase, subsystem=t.Subsystem.UTIL):
         req_schema=(
             t.Param("Index", t.uint8_t, "Nth active entry in the device list"),
         ),
-        rsp_schema=(t.Param("Device", Device, "associated_devices_t structure"),),
+        # XXX: The struct is not packed when sent: `write(&struct, sizeof(struct))`
+        rsp_schema=(t.Param("Device", t.Bytes, "associated_devices_t structure"),),
     )
 
     # a proxy call to the AssocGetWithAddress() function

zigpy_znp/nvram.py

@@ -25,21 +25,19 @@ async def determine_alignment(self) -> None:
         structs are read/written.
         """
 
-        # TODO: Figure out a way to use `c.UTIL.AssocFindDevice.Req(Index=0)`!
-        #       This is the only (known) MT command to just send a struct's in-memory
-        #       representation over serial.
+        # This is the only known MT command to respond with a struct's in-memory
+        # representation over serial.
+        LOGGER.debug("Detecting struct alignment")
+        rsp = await self.znp.request(c.UTIL.AssocFindDevice.Req(Index=0))
 
-        # NWKKEY is almost always present, regardless of adapter state.
-        # It is an 8-bit sequence number, a 16 byte key, and a 32-bit frame counter.
-        # This is at least 1 + 16 + 4 = 21 bytes, or 24 if you have to 32-bit align.
-        value = await self.osal_read(nvids.OsalNvIds.NWKKEY, item_type=t.Bytes)
-
-        if len(value) == 24:
-            self.align_structs = True
-        elif len(value) == 21:
+        if len(rsp.Device) == 28:
             self.align_structs = False
+        elif len(rsp.Device) == 36:
+            # `AssociatedDevice` has an extra member at the end in Z-Stack 3.30 but
+            # the struct does not change in size due to padding.
+            self.align_structs = True
         else:
-            raise ValueError(f"Unexpected value for NWKKEY: {value!r}")
+            raise ValueError(f"Cannot determine alignment from struct: {rsp!r}")
 
         LOGGER.debug("Detected struct alignment: %s", self.align_structs)
 

zigpy_znp/types/structs.py

@@ -217,3 +217,46 @@ class APSLinkKeyTable(
     basic.LVList, length_type=basic.uint16_t, item_type=APSLinkKeyTableEntry
 ):
     pass
+
+
+class LinkInfo(cstruct.CStruct):
+    # Counter of transmission success/failures
+    txCounter: basic.uint8_t
+    # Average of sending rssi values if link staus is enabled
+    # i.e. NWK_LINK_STATUS_PERIOD is defined as non zero
+    txCost: basic.uint8_t
+    # average of received rssi values.
+    # needs to be converted to link cost (1-7) before use
+    rxLqi: basic.uint8_t
+    # security key sequence number
+    inKeySeqNum: basic.uint8_t
+    # security frame counter..
+    inFrmCntr: basic.uint32_t
+    # higher values indicate more failures
+    txFailure: basic.uint16_t
+
+
+class AgingEndDevice(cstruct.CStruct):
+    endDevCfg: basic.uint8_t
+    deviceTimeout: basic.uint32_t
+
+
+class BaseAssociatedDevice(cstruct.CStruct):
+    shortAddr: basic.uint16_t
+    addrIdx: basic.uint16_t
+    nodeRelation: basic.uint8_t
+    devStatus: basic.uint8_t
+    assocCnt: basic.uint8_t
+    age: basic.uint8_t
+    linkInfo: LinkInfo
+    endDev: AgingEndDevice
+    timeoutCounter: basic.uint32_t
+    keepaliveRcv: named.Bool
+
+
+class AssociatedDeviceZStack1(BaseAssociatedDevice):
+    pass
+
+
+class AssociatedDeviceZStack3(BaseAssociatedDevice):
+    ctrl: basic.uint8_t  # This member was added