Add apf_utils for multi-device tests

Test: atest NetworkStaticLibHostPythonTests
Bug: 335368434
Change-Id: I79064abcb88fbcee00ec9ec998ba5a3e2d3478a6

staticlibs/testutils/host/python/apf_utils.py

@@ -0,0 +1,77 @@
+#  Copyright (C) 2024 The Android Open Source Project
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+import re
+from mobly.controllers import android_device
+from net_tests_utils.host.python import adb_utils
+
+
+class PatternNotFoundException(Exception):
+  """Raised when the given pattern cannot be found."""
+
+
+def get_apf_counter(
+    ad: android_device.AndroidDevice, iface: str, counter_name: str
+) -> int:
+  counters = get_apf_counters_from_dumpsys(ad, iface)
+  return counters.get(counter_name, 0)
+
+
+def get_apf_counters_from_dumpsys(
+    ad: android_device.AndroidDevice, iface_name: str
+) -> dict:
+  dumpsys = adb_utils.get_dumpsys_for_service(ad, "network_stack")
+
+  # Extract IpClient section of the specified interface.
+  # This takes inputs like:
+  # IpClient.wlan0
+  #   ...
+  # IpClient.wlan1
+  #   ...
+  iface_pattern = re.compile(
+      r"^IpClient\." + iface_name + r"\n" + r"((^\s.*\n)+)", re.MULTILINE
+  )
+  iface_result = iface_pattern.search(dumpsys)
+  if iface_result is None:
+    raise PatternNotFoundException("Cannot find IpClient for " + iface_name)
+
+  # Extract APF counters section from IpClient section, which looks like:
+  #     APF packet counters:
+  #       COUNTER_NAME: VALUE
+  #       ....
+  apf_pattern = re.compile(
+      r"APF packet counters:.*\n.(\s+[A-Z_0-9]+: \d+\n)+", re.MULTILINE
+  )
+  apf_result = apf_pattern.search(iface_result.group(0))
+  if apf_result is None:
+    raise PatternNotFoundException(
+        "Cannot find APF counters in text: " + iface_result.group(0)
+    )
+
+  # Extract key-value pairs from APF counters section into a list of tuples,
+  # e.g. [('COUNTER1', '1'), ('COUNTER2', '2')].
+  counter_pattern = re.compile(r"(?P<name>[A-Z_0-9]+): (?P<value>\d+)")
+  counter_result = counter_pattern.findall(apf_result.group(0))
+  if counter_result is None:
+    raise PatternNotFoundException(
+        "Cannot extract APF counters in text: " + apf_result.group(0)
+    )
+
+  # Convert into a dict.
+  result = {}
+  for key, value_str in counter_result:
+    result[key] = int(value_str)
+
+  ad.log.debug("Getting apf counters: " + str(result))
+  return result