selftests/bpf: Add test for "bpftool feature" command

Add Python module with tests for "bpftool feature" command, which mainly
checks whether the "full" option is working properly.

Signed-off-by: Michal Rostecki <mrostecki@opensuse.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200226165941.6379-6-mrostecki@opensuse.org

tools/testing/selftests/.gitignore

@@ -3,4 +3,7 @@ gpiogpio-hammer
 gpioinclude/
 gpiolsgpio
 tpm2/SpaceTest.log
-tpm2/*.pyc
+
+# Python bytecode and cache
+__pycache__/
+*.py[cod]

tools/testing/selftests/bpf/Makefile

@@ -62,7 +62,8 @@ TEST_PROGS := test_kmod.sh \
 	test_tc_tunnel.sh \
 	test_tc_edt.sh \
 	test_xdping.sh \
-	test_bpftool_build.sh
+	test_bpftool_build.sh \
+	test_bpftool.sh
 
 TEST_PROGS_EXTENDED := with_addr.sh \
 	with_tunnels.sh \

tools/testing/selftests/bpf/test_bpftool.py

@@ -0,0 +1,178 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 SUSE LLC.
+
+import collections
+import functools
+import json
+import os
+import socket
+import subprocess
+import unittest
+
+
+# Add the source tree of bpftool and /usr/local/sbin to PATH
+cur_dir = os.path.dirname(os.path.realpath(__file__))
+bpftool_dir = os.path.abspath(os.path.join(cur_dir, "..", "..", "..", "..",
+                                           "tools", "bpf", "bpftool"))
+os.environ["PATH"] = bpftool_dir + ":/usr/local/sbin:" + os.environ["PATH"]
+
+
+class IfaceNotFoundError(Exception):
+    pass
+
+
+class UnprivilegedUserError(Exception):
+    pass
+
+
+def _bpftool(args, json=True):
+    _args = ["bpftool"]
+    if json:
+        _args.append("-j")
+    _args.extend(args)
+
+    return subprocess.check_output(_args)
+
+
+def bpftool(args):
+    return _bpftool(args, json=False).decode("utf-8")
+
+
+def bpftool_json(args):
+    res = _bpftool(args)
+    return json.loads(res)
+
+
+def get_default_iface():
+    for iface in socket.if_nameindex():
+        if iface[1] != "lo":
+            return iface[1]
+    raise IfaceNotFoundError("Could not find any network interface to probe")
+
+
+def default_iface(f):
+    @functools.wraps(f)
+    def wrapper(*args, **kwargs):
+        iface = get_default_iface()
+        return f(*args, iface, **kwargs)
+    return wrapper
+
+
+class TestBpftool(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        if os.getuid() != 0:
+            raise UnprivilegedUserError(
+                "This test suite needs root privileges")
+
+    @default_iface
+    def test_feature_dev_json(self, iface):
+        unexpected_helpers = [
+            "bpf_probe_write_user",
+            "bpf_trace_printk",
+        ]
+        expected_keys = [
+            "syscall_config",
+            "program_types",
+            "map_types",
+            "helpers",
+            "misc",
+        ]
+
+        res = bpftool_json(["feature", "probe", "dev", iface])
+        # Check if the result has all expected keys.
+        self.assertCountEqual(res.keys(), expected_keys)
+        # Check if unexpected helpers are not included in helpers probes
+        # result.
+        for helpers in res["helpers"].values():
+            for unexpected_helper in unexpected_helpers:
+                self.assertNotIn(unexpected_helper, helpers)
+
+    def test_feature_kernel(self):
+        test_cases = [
+            bpftool_json(["feature", "probe", "kernel"]),
+            bpftool_json(["feature", "probe"]),
+            bpftool_json(["feature"]),
+        ]
+        unexpected_helpers = [
+            "bpf_probe_write_user",
+            "bpf_trace_printk",
+        ]
+        expected_keys = [
+            "syscall_config",
+            "system_config",
+            "program_types",
+            "map_types",
+            "helpers",
+            "misc",
+        ]
+
+        for tc in test_cases:
+            # Check if the result has all expected keys.
+            self.assertCountEqual(tc.keys(), expected_keys)
+            # Check if unexpected helpers are not included in helpers probes
+            # result.
+            for helpers in tc["helpers"].values():
+                for unexpected_helper in unexpected_helpers:
+                    self.assertNotIn(unexpected_helper, helpers)
+
+    def test_feature_kernel_full(self):
+        test_cases = [
+            bpftool_json(["feature", "probe", "kernel", "full"]),
+            bpftool_json(["feature", "probe", "full"]),
+        ]
+        expected_helpers = [
+            "bpf_probe_write_user",
+            "bpf_trace_printk",
+        ]
+
+        for tc in test_cases:
+            # Check if expected helpers are included at least once in any
+            # helpers list for any program type. Unfortunately we cannot assume
+            # that they will be included in all program types or a specific
+            # subset of programs. It depends on the kernel version and
+            # configuration.
+            found_helpers = False
+
+            for helpers in tc["helpers"].values():
+                if all(expected_helper in helpers
+                       for expected_helper in expected_helpers):
+                    found_helpers = True
+                    break
+
+            self.assertTrue(found_helpers)
+
+    def test_feature_kernel_full_vs_not_full(self):
+        full_res = bpftool_json(["feature", "probe", "full"])
+        not_full_res = bpftool_json(["feature", "probe"])
+        not_full_set = set()
+        full_set = set()
+
+        for helpers in full_res["helpers"].values():
+            for helper in helpers:
+                full_set.add(helper)
+
+        for helpers in not_full_res["helpers"].values():
+            for helper in helpers:
+                not_full_set.add(helper)
+
+        self.assertCountEqual(full_set - not_full_set,
+                                {"bpf_probe_write_user", "bpf_trace_printk"})
+        self.assertCountEqual(not_full_set - full_set, set())
+
+    def test_feature_macros(self):
+        expected_patterns = [
+            r"/\*\*\* System call availability \*\*\*/",
+            r"#define HAVE_BPF_SYSCALL",
+            r"/\*\*\* eBPF program types \*\*\*/",
+            r"#define HAVE.*PROG_TYPE",
+            r"/\*\*\* eBPF map types \*\*\*/",
+            r"#define HAVE.*MAP_TYPE",
+            r"/\*\*\* eBPF helper functions \*\*\*/",
+            r"#define HAVE.*HELPER",
+            r"/\*\*\* eBPF misc features \*\*\*/",
+        ]
+
+        res = bpftool(["feature", "probe", "macros"])
+        for pattern in expected_patterns:
+            self.assertRegex(res, pattern)

tools/testing/selftests/bpf/test_bpftool.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 SUSE LLC.
+
+python3 -m unittest -v test_bpftool.TestBpftool