ble: de-duplicate beacon code for eddystone

(includes 1 fix-up; excludes iBeacon in #1893)

Author: micolous

scapy/contrib/eddystone.py

@@ -13,13 +13,12 @@
 # scapy.contrib.status = loads
 
 from scapy.compat import orb
-from scapy.packet import bind_layers, Packet
 from scapy.fields import IntField, SignedByteField, StrField, BitField, \
     StrFixedLenField, ShortField, FixedPointField, ByteEnumField
 from scapy.layers.bluetooth import EIR_Hdr, EIR_ServiceData16BitUUID, \
-    EIR_Flags, EIR_CompleteList16BitServiceUUIDs, HCI_Hdr, HCI_Command_Hdr, \
-    HCI_Cmd_LE_Set_Advertising_Data, HCI_LE_Meta_Advertising_Report
+    EIR_CompleteList16BitServiceUUIDs, LowEnergyBeaconHelper
 from scapy.modules import six
+from scapy.packet import bind_layers, Packet
 
 EDDYSTONE_UUID = 0xfeaa
 
@@ -93,7 +92,7 @@ def any2i(self, pkt, x):
         return x
 
 
-class Eddystone_Frame(Packet):
+class Eddystone_Frame(Packet, LowEnergyBeaconHelper):
     # https://github.com/google/eddystone/blob/master/protocol-specification.md
     name = "Eddystone Frame"
     fields_desc = [
@@ -104,33 +103,12 @@ class Eddystone_Frame(Packet):
     def build_eir(self):
         """Builds a list of EIR messages to wrap this frame."""
 
-        return [
-            EIR_Hdr() / EIR_Flags(flags=[
-                "general_disc_mode", "br_edr_not_supported"]),
+        return LowEnergyBeaconHelper.base_eir + [
             EIR_Hdr() / EIR_CompleteList16BitServiceUUIDs(svc_uuids=[
                 EDDYSTONE_UUID]),
             EIR_Hdr() / EIR_ServiceData16BitUUID() / self
         ]
 
-    def build_advertising_report(self):
-        """Builds HCI_LE_Meta_Advertising_Report containing this frame."""
-
-        return HCI_LE_Meta_Advertising_Report(
-            type=0,   # Undirected
-            atype=1,  # Random address
-            data=self.build_eir()
-        )
-
-    def build_set_advertising_data(self):
-        """Builds a HCI_Cmd_LE_Set_Advertising_Data containing this frame.
-
-        This includes the HCI_Hdr and HCI_Command_Hdr layers.
-        """
-
-        return HCI_Hdr() / HCI_Command_Hdr() / HCI_Cmd_LE_Set_Advertising_Data(
-            data=self.build_eir()
-        )
-
 
 class Eddystone_UID(Packet):
     # https://github.com/google/eddystone/tree/master/eddystone-uid

scapy/layers/bluetooth.py

@@ -1192,6 +1192,61 @@ class HCI_LE_Meta_Long_Term_Key_Request(Packet):
 bind_layers(SM_Hdr, SM_Signing_Information, sm_command=0x0a)
 
 
+###########
+# Helpers #
+###########
+
+class LowEnergyBeaconHelper:
+    """
+    Helpers for building packets for Bluetooth Low Energy Beacons.
+
+    Implementors provide a :meth:`build_eir` implementation.
+
+    This is designed to be used as a mix-in -- see
+    ``scapy.contrib.eddystone`` and ``scapy.contrib.ibeacon`` for examples.
+    """
+
+    # Basic flags that should be used by most beacons.
+    base_eir = [EIR_Hdr() / EIR_Flags(flags=[
+        "general_disc_mode", "br_edr_not_supported"]), ]
+
+    def build_eir(self):
+        """
+        Builds a list of EIR messages to wrap this frame.
+
+        Users of this helper must implement this method.
+
+        :returns: List of HCI_Hdr with payloads that describe this beacon type
+        :rtype: list[HCI_Hdr]
+        """
+        raise NotImplementedError("build_eir")
+
+    def build_advertising_report(self):
+        """
+        Builds a HCI_LE_Meta_Advertising_Report containing this frame.
+
+        :rtype: HCI_LE_Meta_Advertising_Report
+        """
+
+        return HCI_LE_Meta_Advertising_Report(
+            type=0,   # Undirected
+            atype=1,  # Random address
+            data=self.build_eir()
+        )
+
+    def build_set_advertising_data(self):
+        """Builds a HCI_Cmd_LE_Set_Advertising_Data containing this frame.
+
+        This includes the :class:`HCI_Hdr` and :class:`HCI_Command_Hdr` layers.
+
+        :rtype: HCI_Hdr
+        """
+
+        return HCI_Hdr() / HCI_Command_Hdr() / HCI_Cmd_LE_Set_Advertising_Data(
+            data=self.build_eir()
+        )
+
+
 ###########
 # Sockets #
 ###########