BpfNetworkStats: introduce IfIndexToNameFunc

Test: TreeHugger, atest libnetworkstats_test
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I61edb3981c19718e177307c3df89de635598f2fd
diff --git a/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp b/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
index def5f88..e9784ff 100644
--- a/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
+++ b/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
@@ -50,6 +50,10 @@
     return ifaceStatsMap;
 }
 
+Result<IfaceValue> ifindex2name(const uint32_t ifindex) {
+    return getIfaceIndexNameMap().readValue(ifindex);
+}
+
 void bpfRegisterIface(const char* iface) {
     if (!iface) return;
     if (strlen(iface) >= sizeof(IfaceValue)) return;
@@ -78,14 +82,14 @@
 
 int bpfGetIfaceStatsInternal(const char* iface, StatsValue* stats,
                              const BpfMapRO<uint32_t, StatsValue>& ifaceStatsMap,
-                             const BpfMapRO<uint32_t, IfaceValue>& ifaceNameMap) {
+                             const IfIndexToNameFunc ifindex2name) {
     *stats = {};
     int64_t unknownIfaceBytesTotal = 0;
     const auto processIfaceStats =
-            [iface, stats, &ifaceNameMap, &unknownIfaceBytesTotal](
+            [iface, stats, ifindex2name, &unknownIfaceBytesTotal](
                     const uint32_t& key,
                     const BpfMapRO<uint32_t, StatsValue>& ifaceStatsMap) -> Result<void> {
-        Result<IfaceValue> ifname = ifaceNameMap.readValue(key);
+        Result<IfaceValue> ifname = ifindex2name(key);
         if (!ifname.ok()) {
             maybeLogUnknownIface(key, ifaceStatsMap, key, &unknownIfaceBytesTotal);
             return Result<void>();
@@ -104,7 +108,7 @@
 }
 
 int bpfGetIfaceStats(const char* iface, StatsValue* stats) {
-    return bpfGetIfaceStatsInternal(iface, stats, getIfaceStatsMap(), getIfaceIndexNameMap());
+    return bpfGetIfaceStatsInternal(iface, stats, getIfaceStatsMap(), ifindex2name);
 }
 
 int bpfGetIfIndexStatsInternal(uint32_t ifindex, StatsValue* stats,
@@ -138,13 +142,13 @@
 
 int parseBpfNetworkStatsDetailInternal(std::vector<stats_line>& lines,
                                        const BpfMapRO<StatsKey, StatsValue>& statsMap,
-                                       const BpfMapRO<uint32_t, IfaceValue>& ifaceMap) {
+                                       const IfIndexToNameFunc ifindex2name) {
     int64_t unknownIfaceBytesTotal = 0;
     const auto processDetailUidStats =
-            [&lines, &unknownIfaceBytesTotal, &ifaceMap](
+            [&lines, &unknownIfaceBytesTotal, &ifindex2name](
                     const StatsKey& key,
                     const BpfMapRO<StatsKey, StatsValue>& statsMap) -> Result<void> {
-        Result<IfaceValue> ifname = ifaceMap.readValue(key.ifaceIndex);
+        Result<IfaceValue> ifname = ifindex2name(key.ifaceIndex);
         if (!ifname.ok()) {
             maybeLogUnknownIface(key.ifaceIndex, statsMap, key, &unknownIfaceBytesTotal);
             return Result<void>();
@@ -212,7 +216,7 @@
     // TODO: the above comment feels like it may be obsolete / out of date,
     // since we no longer swap the map via netd binder rpc - though we do
     // still swap it.
-    int ret = parseBpfNetworkStatsDetailInternal(*lines, *inactiveStatsMap, getIfaceIndexNameMap());
+    int ret = parseBpfNetworkStatsDetailInternal(*lines, *inactiveStatsMap, ifindex2name);
     if (ret) {
         ALOGE("parse detail network stats failed: %s", strerror(errno));
         return ret;
@@ -229,12 +233,12 @@
 
 int parseBpfNetworkStatsDevInternal(std::vector<stats_line>& lines,
                                     const BpfMapRO<uint32_t, StatsValue>& statsMap,
-                                    const BpfMapRO<uint32_t, IfaceValue>& ifaceMap) {
+                                    const IfIndexToNameFunc ifindex2name) {
     int64_t unknownIfaceBytesTotal = 0;
-    const auto processDetailIfaceStats = [&lines, &unknownIfaceBytesTotal, &ifaceMap, &statsMap](
+    const auto processDetailIfaceStats = [&lines, &unknownIfaceBytesTotal, ifindex2name, &statsMap](
                                              const uint32_t& key, const StatsValue& value,
                                              const BpfMapRO<uint32_t, StatsValue>&) {
-        Result<IfaceValue> ifname = ifaceMap.readValue(key);
+        Result<IfaceValue> ifname = ifindex2name(key);
         if (!ifname.ok()) {
             maybeLogUnknownIface(key, statsMap, key, &unknownIfaceBytesTotal);
             return Result<void>();
@@ -259,7 +263,7 @@
 }
 
 int parseBpfNetworkStatsDev(std::vector<stats_line>* lines) {
-    return parseBpfNetworkStatsDevInternal(*lines, getIfaceStatsMap(), getIfaceIndexNameMap());
+    return parseBpfNetworkStatsDevInternal(*lines, getIfaceStatsMap(), ifindex2name);
 }
 
 void groupNetworkStats(std::vector<stats_line>& lines) {
diff --git a/service-t/native/libs/libnetworkstats/BpfNetworkStatsTest.cpp b/service-t/native/libs/libnetworkstats/BpfNetworkStatsTest.cpp
index 57822fc..484c166 100644
--- a/service-t/native/libs/libnetworkstats/BpfNetworkStatsTest.cpp
+++ b/service-t/native/libs/libnetworkstats/BpfNetworkStatsTest.cpp
@@ -77,6 +77,10 @@
     BpfMap<uint32_t, IfaceValue> mFakeIfaceIndexNameMap;
     BpfMap<uint32_t, StatsValue> mFakeIfaceStatsMap;
 
+    IfIndexToNameFunc mIfIndex2Name = [this](const uint32_t ifindex){
+        return mFakeIfaceIndexNameMap.readValue(ifindex);
+    };
+
     void SetUp() {
         ASSERT_EQ(0, setrlimitForTest());
 
@@ -228,7 +232,7 @@
     populateFakeStats(TEST_UID1, 0, IFACE_INDEX1, TEST_COUNTERSET0, value1, mFakeStatsMap);
     populateFakeStats(TEST_UID1, 0, IFACE_INDEX2, TEST_COUNTERSET1, value1, mFakeStatsMap);
     populateFakeStats(TEST_UID2, 0, IFACE_INDEX3, TEST_COUNTERSET1, value1, mFakeStatsMap);
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((unsigned long)3, lines.size());
 }
 
@@ -256,16 +260,15 @@
     EXPECT_RESULT_OK(mFakeIfaceStatsMap.writeValue(ifaceStatsKey, value1, BPF_ANY));
 
     StatsValue result1 = {};
-    ASSERT_EQ(0, bpfGetIfaceStatsInternal(IFACE_NAME1, &result1, mFakeIfaceStatsMap,
-                                          mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0,
+              bpfGetIfaceStatsInternal(IFACE_NAME1, &result1, mFakeIfaceStatsMap, mIfIndex2Name));
     expectStatsEqual(value1, result1);
     StatsValue result2 = {};
-    ASSERT_EQ(0, bpfGetIfaceStatsInternal(IFACE_NAME2, &result2, mFakeIfaceStatsMap,
-                                          mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0,
+              bpfGetIfaceStatsInternal(IFACE_NAME2, &result2, mFakeIfaceStatsMap, mIfIndex2Name));
     expectStatsEqual(value2, result2);
     StatsValue totalResult = {};
-    ASSERT_EQ(0, bpfGetIfaceStatsInternal(NULL, &totalResult, mFakeIfaceStatsMap,
-                                          mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, bpfGetIfaceStatsInternal(NULL, &totalResult, mFakeIfaceStatsMap, mIfIndex2Name));
     StatsValue totalValue = {
             .rxPackets = TEST_PACKET0 * 2 + TEST_PACKET1,
             .rxBytes = TEST_BYTES0 * 2 + TEST_BYTES1,
@@ -304,7 +307,7 @@
                       mFakeStatsMap);
     populateFakeStats(TEST_UID2, TEST_TAG, IFACE_INDEX1, TEST_COUNTERSET0, value1, mFakeStatsMap);
     std::vector<stats_line> lines;
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((unsigned long)7, lines.size());
 }
 
@@ -324,7 +327,7 @@
     populateFakeStats(TEST_UID1, 0, IFACE_INDEX1, TEST_COUNTERSET1, value1, mFakeStatsMap);
     populateFakeStats(TEST_UID2, 0, IFACE_INDEX1, TEST_COUNTERSET0, value1, mFakeStatsMap);
     std::vector<stats_line> lines;
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((unsigned long)4, lines.size());
 }
 
@@ -365,7 +368,7 @@
     ASSERT_EQ(-1, unknownIfaceBytesTotal);
     std::vector<stats_line> lines;
     // TODO: find a way to test the total of unknown Iface Bytes go above limit.
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((unsigned long)1, lines.size());
     expectStatsLineEqual(value1, IFACE_NAME1, TEST_UID1, TEST_COUNTERSET0, 0, lines.front());
 }
@@ -396,8 +399,7 @@
     ifaceStatsKey = IFACE_INDEX4;
     EXPECT_RESULT_OK(mFakeIfaceStatsMap.writeValue(ifaceStatsKey, value2, BPF_ANY));
     std::vector<stats_line> lines;
-    ASSERT_EQ(0,
-              parseBpfNetworkStatsDevInternal(lines, mFakeIfaceStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDevInternal(lines, mFakeIfaceStatsMap, mIfIndex2Name));
     ASSERT_EQ((unsigned long)4, lines.size());
 
     expectStatsLineEqual(value1, IFACE_NAME1, UID_ALL, SET_ALL, TAG_NONE, lines[0]);
@@ -441,13 +443,13 @@
     std::vector<stats_line> lines;
 
     // Test empty stats.
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((size_t) 0, lines.size());
     lines.clear();
 
     // Test 1 line stats.
     populateFakeStats(TEST_UID1, TEST_TAG, IFACE_INDEX1, TEST_COUNTERSET0, value1, mFakeStatsMap);
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((size_t) 2, lines.size());  // TEST_TAG != 0 -> 1 entry becomes 2 lines
     expectStatsLineEqual(value1, IFACE_NAME1, TEST_UID1, TEST_COUNTERSET0, 0, lines[0]);
     expectStatsLineEqual(value1, IFACE_NAME1, TEST_UID1, TEST_COUNTERSET0, TEST_TAG, lines[1]);
@@ -459,7 +461,7 @@
     populateFakeStats(TEST_UID1, TEST_TAG + 1, IFACE_INDEX1, TEST_COUNTERSET0, value2,
                       mFakeStatsMap);
     populateFakeStats(TEST_UID2, TEST_TAG, IFACE_INDEX1, TEST_COUNTERSET0, value1, mFakeStatsMap);
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((size_t) 9, lines.size());
     lines.clear();
 
@@ -467,7 +469,7 @@
     populateFakeStats(TEST_UID1, TEST_TAG, IFACE_INDEX3, TEST_COUNTERSET0, value1, mFakeStatsMap);
     populateFakeStats(TEST_UID2, TEST_TAG, IFACE_INDEX3, TEST_COUNTERSET0, value1, mFakeStatsMap);
 
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((size_t) 9, lines.size());
 
     // Verify Sorted & Grouped.
@@ -492,8 +494,7 @@
     ifaceStatsKey = IFACE_INDEX3;
     EXPECT_RESULT_OK(mFakeIfaceStatsMap.writeValue(ifaceStatsKey, value1, BPF_ANY));
 
-    ASSERT_EQ(0,
-              parseBpfNetworkStatsDevInternal(lines, mFakeIfaceStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDevInternal(lines, mFakeIfaceStatsMap, mIfIndex2Name));
     ASSERT_EQ((size_t) 2, lines.size());
 
     expectStatsLineEqual(value3, IFACE_NAME1, UID_ALL, SET_ALL, TAG_NONE, lines[0]);
@@ -534,7 +535,7 @@
     // TODO: Mutate counterSet and enlarge TEST_MAP_SIZE if overflow on counterSet is possible.
 
     std::vector<stats_line> lines;
-    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mFakeIfaceIndexNameMap));
+    ASSERT_EQ(0, parseBpfNetworkStatsDetailInternal(lines, mFakeStatsMap, mIfIndex2Name));
     ASSERT_EQ((size_t) 12, lines.size());
 
     // Uid 0 first
diff --git a/service-t/native/libs/libnetworkstats/include/netdbpf/BpfNetworkStats.h b/service-t/native/libs/libnetworkstats/include/netdbpf/BpfNetworkStats.h
index 173dee4..59eb195 100644
--- a/service-t/native/libs/libnetworkstats/include/netdbpf/BpfNetworkStats.h
+++ b/service-t/native/libs/libnetworkstats/include/netdbpf/BpfNetworkStats.h
@@ -55,20 +55,25 @@
 bool operator==(const stats_line& lhs, const stats_line& rhs);
 bool operator<(const stats_line& lhs, const stats_line& rhs);
 
+// This mirrors BpfMap.h's:
+//   Result<Value> readValue(const Key key) const
+// for a BpfMap<uint32_t, IfaceValue>
+using IfIndexToNameFunc = std::function<Result<IfaceValue>(const uint32_t)>;
+
 // For test only
 int bpfGetUidStatsInternal(uid_t uid, StatsValue* stats,
                            const BpfMapRO<uint32_t, StatsValue>& appUidStatsMap);
 // For test only
 int bpfGetIfaceStatsInternal(const char* iface, StatsValue* stats,
                              const BpfMapRO<uint32_t, StatsValue>& ifaceStatsMap,
-                             const BpfMapRO<uint32_t, IfaceValue>& ifaceNameMap);
+                             const IfIndexToNameFunc ifindex2name);
 // For test only
 int bpfGetIfIndexStatsInternal(uint32_t ifindex, StatsValue* stats,
                                const BpfMapRO<uint32_t, StatsValue>& ifaceStatsMap);
 // For test only
 int parseBpfNetworkStatsDetailInternal(std::vector<stats_line>& lines,
                                        const BpfMapRO<StatsKey, StatsValue>& statsMap,
-                                       const BpfMapRO<uint32_t, IfaceValue>& ifaceMap);
+                                       const IfIndexToNameFunc ifindex2name);
 // For test only
 int cleanStatsMapInternal(const base::unique_fd& cookieTagMap, const base::unique_fd& tagStatsMap);
 
@@ -98,7 +103,7 @@
 // For test only
 int parseBpfNetworkStatsDevInternal(std::vector<stats_line>& lines,
                                     const BpfMapRO<uint32_t, StatsValue>& statsMap,
-                                    const BpfMapRO<uint32_t, IfaceValue>& ifaceMap);
+                                    const IfIndexToNameFunc ifindex2name);
 
 void bpfRegisterIface(const char* iface);
 int bpfGetUidStats(uid_t uid, StatsValue* stats);