From dcb5228f2c0554cbee98be6477848451eb7fa94e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= <maze@google.com>
Date: Sun, 17 Jan 2021 03:36:34 -0800
Subject: [PATCH] remove BpfLevel and getBpfSupportLevel in favour of
 isAtLeastKernelVersion
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Test: builds, atest, TreeHugger
Bug: 167500195
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I50dbed1843a8c2802e1b416281e193ae7d282a99
---
 libbpf_android/BpfUtils.cpp           | 18 ---------------
 libbpf_android/include/bpf/BpfUtils.h | 33 ++++++++++++---------------
 2 files changed, 14 insertions(+), 37 deletions(-)

diff --git a/libbpf_android/BpfUtils.cpp b/libbpf_android/BpfUtils.cpp
index 5fed9c2..8689192 100644
--- a/libbpf_android/BpfUtils.cpp
+++ b/libbpf_android/BpfUtils.cpp
@@ -94,8 +94,6 @@ int setrlimitForTest() {
     return res;
 }
 
-#define KVER(a, b, c) ((a)*65536 + (b)*256 + (c))
-
 unsigned kernelVersion() {
     struct utsname buf;
     int ret = uname(&buf);
@@ -112,21 +110,5 @@ unsigned kernelVersion() {
     return KVER(kver_major, kver_minor, kver_sub);
 }
 
-static BpfLevel getUncachedBpfSupportLevel() {
-    unsigned kver = kernelVersion();
-
-    if (kver >= KVER(5, 4, 0)) return BpfLevel::EXTENDED_5_4;
-    if (kver >= KVER(4, 19, 0)) return BpfLevel::EXTENDED_4_19;
-    if (kver >= KVER(4, 14, 0)) return BpfLevel::EXTENDED_4_14;
-
-    // Basic BPF support is required on all devices.
-    return BpfLevel::BASIC_4_9;
-}
-
-BpfLevel getBpfSupportLevel() {
-    static BpfLevel cache = getUncachedBpfSupportLevel();
-    return cache;
-}
-
 }  // namespace bpf
 }  // namespace android
diff --git a/libbpf_android/include/bpf/BpfUtils.h b/libbpf_android/include/bpf/BpfUtils.h
index 0843339..08c1844 100644
--- a/libbpf_android/include/bpf/BpfUtils.h
+++ b/libbpf_android/include/bpf/BpfUtils.h
@@ -30,17 +30,6 @@
 namespace android {
 namespace bpf {
 
-enum class BpfLevel {
-    // Devices shipped in P with android 4.9 kernel only have the basic eBPF
-    // functionalities such as xt_bpf and cgroup skb filter.
-    BASIC_4_9,
-    // For devices that have 4.14 kernel. It supports advanced features like
-    // map_in_map and cgroup socket filter.
-    EXTENDED_4_14,
-    EXTENDED_4_19,
-    EXTENDED_5_4,
-};
-
 constexpr const int OVERFLOW_COUNTERSET = 2;
 
 constexpr const uint64_t NONEXISTENT_COOKIE = 0;
@@ -50,20 +39,26 @@ constexpr const int MINIMUM_API_REQUIRED = 28;
 uint64_t getSocketCookie(int sockFd);
 int synchronizeKernelRCU();
 int setrlimitForTest();
+
+#define KVER(a, b, c) ((a)*65536 + (b)*256 + (c))
+
 unsigned kernelVersion();
-BpfLevel getBpfSupportLevel();
+
+static inline bool isAtLeastKernelVersion(unsigned major, unsigned minor, unsigned sub) {
+    return kernelVersion() >= KVER(major, minor, sub);
+}
 
 inline bool isBpfSupported() {
     return true;
 }
 
-#define SKIP_IF_EXTENDED_BPF_NOT_SUPPORTED                                                \
-    do {                                                                                  \
-        if (android::bpf::getBpfSupportLevel() < android::bpf::BpfLevel::EXTENDED_4_14) { \
-            GTEST_LOG_(INFO) << "This test is skipped since extended bpf feature"         \
-                             << "not supported\n";                                        \
-            return;                                                                       \
-        }                                                                                 \
+#define SKIP_IF_EXTENDED_BPF_NOT_SUPPORTED                                        \
+    do {                                                                          \
+        if (!android::bpf::isAtLeastKernelVersion(4, 14, 0)) {                    \
+            GTEST_LOG_(INFO) << "This test is skipped since extended bpf feature" \
+                             << "not supported\n";                                \
+            return;                                                               \
+        }                                                                         \
     } while (0)
 
 }  // namespace bpf