[virtual-time-simulator] optimize ACK radio events (#5559)

This commit optimizes Virtual Time Simulator by only sending ACK to
nodes that are expecting it.

tests/scripts/thread-cert/Makefile.am

@@ -184,6 +184,7 @@ EXTRA_DIST                                                         = \
     pktverify/test_info.py                                           \
     pktverify/utils.py                                               \
     pktverify/verify_result.py                                       \
+    wpan.py                                                          \
     $(NULL)
 
 check_PROGRAMS                                                     = \

tests/scripts/thread-cert/simulator.py

@@ -40,6 +40,7 @@ import config
 import mesh_cop
 import message
 import pcap
+import wpan
 
 
 def dbg_print(*args):
@@ -162,6 +163,8 @@ class VirtualTime(BaseSimulator):
         self.current_time = 0
         self.current_event = None
         self.awake_devices = set()
+        self._nodes_by_ack_seq = {}
+        self._node_ack_seq = {}
 
         self._pcap = pcap.PcapCodec(os.getenv('TEST_NAME', 'current'))
         # the addr for spinel-cli sending OT_SIM_EVENT_POSTCMD
@@ -325,7 +328,15 @@ class VirtualTime(BaseSimulator):
             elif type == self.OT_SIM_EVENT_RADIO_RECEIVED:
                 assert self._is_radio(addr)
                 # add radio receive events event queue
-                for device in self.devices:
+                frame_info = wpan.dissect(data)
+
+                recv_devices = None
+                if frame_info.frame_type == wpan.FrameType.ACK:
+                    recv_devices = self._nodes_by_ack_seq.get(frame_info.seq_no)
+
+                recv_devices = recv_devices or self.devices.keys()
+
+                for device in recv_devices:
                     if device != addr and self._is_radio(device):
                         event = (
                             event_time,
@@ -354,6 +365,9 @@ class VirtualTime(BaseSimulator):
                 self.event_sequence += 1
                 bisect.insort(self.event_queue, event)
 
+                if frame_info.frame_type != wpan.FrameType.ACK and not frame_info.is_broadcast:
+                    self._on_ack_seq_change(addr, frame_info.seq_no)
+
                 self.awake_devices.add(addr)
 
             elif type == self.OT_SIM_EVENT_RADIO_SPINEL_WRITE:
@@ -400,6 +414,14 @@ class VirtualTime(BaseSimulator):
                 if self.current_nodeid == nodeid:
                     self.current_nodeid = None
 
+    def _on_ack_seq_change(self, device: tuple, seq_no: int):
+        old_seq = self._node_ack_seq.pop(device, None)
+        if old_seq is not None:
+            self._nodes_by_ack_seq[old_seq].remove(device)
+
+        self._node_ack_seq[device] = seq_no
+        self._nodes_by_ack_seq.setdefault(seq_no, set()).add(device)
+
     def _send_message(self, message, addr):
         while True:
             try:

tests/scripts/thread-cert/wpan.py

@@ -0,0 +1,138 @@
+#!/usr/bin/env python3
+#
+#  Copyright (c) 2020, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 'AS IS'
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+
+import struct
+
+from collections import namedtuple
+from enum import Enum
+
+FCF_FRAME_BEACON = 0 << 0
+FCF_FRAME_DATA = 1 << 0
+FCF_FRAME_ACK = 2 << 0
+FCF_FRAME_MAC_CMD = 3 << 0
+FCF_FRAME_TYPE_MASK = 7 << 0
+FCF_SECURITY_ENABLED = 1 << 3
+FCF_FRAME_PENDING = 1 << 4
+FCF_ACK_REQUEST = 1 << 5
+FCF_PANID_COMPRESSION = 1 << 6
+FCF_IE_PRESENT = 1 << 9
+FCF_DST_ADDR_NONE = 0 << 10
+FCF_DST_ADDR_SHORT = 2 << 10
+FCF_DST_ADDR_EXT = 3 << 10
+FCF_DST_ADDR_MASK = 3 << 10
+FCF_FRAME_VERSION_2006 = 1 << 12
+FCF_FRAME_VERSION_2015 = 2 << 12
+FCF_FRAME_VERSION_MASK = 3 << 12
+FCF_SRC_ADDR_NONE = 0 << 14
+FCF_SRC_ADDR_SHORT = 2 << 14
+FCF_SRC_ADDR_EXT = 3 << 14
+FCD_SRC_ADDR_MASK = 3 << 14
+
+
+class DstAddrMode(Enum):
+    NONE = 0
+    RESERVED = 1
+    SHORT = 2
+    EXTENDED = 3
+
+
+class FrameType(Enum):
+    BEACON = 0
+    DATA = 1
+    ACK = 2
+    COMMAND = 3
+
+
+class WpanFrameInfo(namedtuple('WpanFrameInfo', ['fcf', 'seq_no', 'dst_extaddr', 'dst_short'])):
+
+    @property
+    def frame_type(self) -> FrameType:
+        return FrameType(self.fcf & 0x7)
+
+    @property
+    def dst_addr_mode(self) -> DstAddrMode:
+        return DstAddrMode((self.fcf & 0x0c00) >> 10)
+
+    @property
+    def is_broadcast(self) -> bool:
+        return self.dst_addr_mode == DstAddrMode.SHORT and self.dst_short == 0xffff
+
+
+def _is_version_2015(fcf: int) -> bool:
+    return (fcf & FCF_FRAME_VERSION_MASK) == FCF_FRAME_VERSION_2015
+
+
+def _is_dst_addr_present(fcf: int) -> bool:
+    dst_addr_mode = DstAddrMode((fcf & 0x0c00) >> 10)
+    return dst_addr_mode != DstAddrMode.NONE
+
+
+_DST_PAN_ID_NOT_PRESENT_SET = {
+    FCF_DST_ADDR_NONE | FCF_SRC_ADDR_NONE,
+    FCF_DST_ADDR_EXT | FCF_SRC_ADDR_NONE | FCF_PANID_COMPRESSION,
+    FCF_DST_ADDR_SHORT | FCF_SRC_ADDR_NONE | FCF_PANID_COMPRESSION,
+    FCF_DST_ADDR_NONE | FCF_SRC_ADDR_EXT,
+    FCF_DST_ADDR_NONE | FCF_SRC_ADDR_SHORT,
+    FCF_DST_ADDR_NONE | FCF_SRC_ADDR_EXT | FCF_PANID_COMPRESSION,
+    FCF_DST_ADDR_NONE | FCF_SRC_ADDR_SHORT | FCF_PANID_COMPRESSION,
+    FCF_DST_ADDR_EXT | FCF_SRC_ADDR_EXT | FCF_PANID_COMPRESSION,
+}
+
+
+def _is_dst_pan_id_present(fcf: int) -> bool:
+    if _is_version_2015(fcf):
+        v = fcf & (FCF_DST_ADDR_MASK | FCD_SRC_ADDR_MASK | FCF_PANID_COMPRESSION)
+        present = v not in _DST_PAN_ID_NOT_PRESENT_SET
+    else:
+        present = _is_dst_addr_present(fcf)
+
+    return present
+
+
+def dissect(frame: bytes) -> WpanFrameInfo:
+    fcf = struct.unpack("<H", frame[1:3])[0]
+
+    seq_no = frame[3]
+
+    dst_addr_mode = (fcf & 0x0c00) >> 10
+
+    dst_extaddr, dst_short = None, None
+
+    if dst_addr_mode in [DstAddrMode.SHORT.value, DstAddrMode.EXTENDED.value]:
+        offset = 4
+
+        if _is_dst_pan_id_present(fcf):
+            offset += 2
+
+        if dst_addr_mode == DstAddrMode.SHORT.value:
+            dst_short = struct.unpack('<H', frame[offset:offset + 2])[0]
+        else:
+            dst_extaddr = '%016x' % struct.unpack('<Q', frame[offset:offset + 8])[0]
+
+    return WpanFrameInfo(fcf=fcf, seq_no=seq_no, dst_extaddr=dst_extaddr, dst_short=dst_short)