commit 9d39969c80f25efad4c2861ff0b87729b2f2e046
author Maciej Żenczykowski <maze@google.com> Fri Jun 24 17:35:51 2022 +0000
committer Maciej Żenczykowski <maze@google.com> Fri Jun 24 17:41:49 2022 +0000
tree a48dbcdadb4e5c2718a15a891acd5ad3981eb252
parent 522cea7d4eca8b0c80b78fa187e6b0f24e10994d

BpfNetworkStats - remove spurious code & use static maps

frameworks/libs/net/common/native/bpf_headers/include/bpf/BpfMap.h
(which is a mainline automerged path)

already aborts() on failure in the path taking constructor
(by calling abortOnKeyOrValueSizeMismatch), and as such
checking for isValid afterwards is pointless.

Also, there's no reason to waste cpu cycles opening and closing these maps, and creating and destroying the map objects.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Icb5567ee32ca9a00fd8aeb565066716d350f1292

service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp

diff --git a/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp b/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
index c67821f..6605428 100644
--- a/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
+++ b/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
@@ -58,13 +58,7 @@
 }
 
 int bpfGetUidStats(uid_t uid, Stats* stats) {
-    BpfMapRO<uint32_t, StatsValue> appUidStatsMap(APP_UID_STATS_MAP_PATH);
-
-    if (!appUidStatsMap.isValid()) {
-        int ret = -errno;
-        ALOGE("Opening appUidStatsMap(%s) failed: %s", APP_UID_STATS_MAP_PATH, strerror(errno));
-        return ret;
-    }
+    static BpfMapRO<uint32_t, StatsValue> appUidStatsMap(APP_UID_STATS_MAP_PATH);
     return bpfGetUidStatsInternal(uid, stats, appUidStatsMap);
 }
 
@@ -100,19 +94,8 @@
 }
 
 int bpfGetIfaceStats(const char* iface, Stats* stats) {
-    BpfMapRO<uint32_t, StatsValue> ifaceStatsMap(IFACE_STATS_MAP_PATH);
-    int ret;
-    if (!ifaceStatsMap.isValid()) {
-        ret = -errno;
-        ALOGE("get ifaceStats map fd failed: %s", strerror(errno));
-        return ret;
-    }
-    BpfMapRO<uint32_t, IfaceValue> ifaceIndexNameMap(IFACE_INDEX_NAME_MAP_PATH);
-    if (!ifaceIndexNameMap.isValid()) {
-        ret = -errno;
-        ALOGE("get ifaceIndexName map fd failed: %s", strerror(errno));
-        return ret;
-    }
+    static BpfMapRO<uint32_t, StatsValue> ifaceStatsMap(IFACE_STATS_MAP_PATH);
+    static BpfMapRO<uint32_t, IfaceValue> ifaceIndexNameMap(IFACE_INDEX_NAME_MAP_PATH);
     return bpfGetIfaceStatsInternal(iface, stats, ifaceStatsMap, ifaceIndexNameMap);
 }
 
@@ -186,19 +169,8 @@
 int parseBpfNetworkStatsDetail(std::vector<stats_line>* lines,
                                const std::vector<std::string>& limitIfaces, int limitTag,
                                int limitUid) {
-    BpfMapRO<uint32_t, IfaceValue> ifaceIndexNameMap(IFACE_INDEX_NAME_MAP_PATH);
-    if (!ifaceIndexNameMap.isValid()) {
-        int ret = -errno;
-        ALOGE("get ifaceIndexName map fd failed: %s", strerror(errno));
-        return ret;
-    }
-
-    BpfMapRO<uint32_t, uint32_t> configurationMap(CONFIGURATION_MAP_PATH);
-    if (!configurationMap.isValid()) {
-        int ret = -errno;
-        ALOGE("get configuration map fd failed: %s", strerror(errno));
-        return ret;
-    }
+    static BpfMapRO<uint32_t, IfaceValue> ifaceIndexNameMap(IFACE_INDEX_NAME_MAP_PATH);
+    static BpfMapRO<uint32_t, uint32_t> configurationMap(CONFIGURATION_MAP_PATH);
     auto configuration = configurationMap.readValue(CURRENT_STATS_MAP_CONFIGURATION_KEY);
     if (!configuration.ok()) {
         ALOGE("Cannot read the old configuration from map: %s",
@@ -210,12 +182,8 @@
         return -EINVAL;
     }
     const char* statsMapPath = STATS_MAP_PATH[configuration.value()];
+    // TODO: fix this to not constantly reopen the bpf map
     BpfMap<StatsKey, StatsValue> statsMap(statsMapPath);
-    if (!statsMap.isValid()) {
-        int ret = -errno;
-        ALOGE("get stats map fd failed: %s, path: %s", strerror(errno), statsMapPath);
-        return ret;
-    }
 
     // It is safe to read and clear the old map now since the
     // networkStatsFactory should call netd to swap the map in advance already.
@@ -266,20 +234,8 @@
 }
 
 int parseBpfNetworkStatsDev(std::vector<stats_line>* lines) {
-    int ret = 0;
-    BpfMapRO<uint32_t, IfaceValue> ifaceIndexNameMap(IFACE_INDEX_NAME_MAP_PATH);
-    if (!ifaceIndexNameMap.isValid()) {
-        ret = -errno;
-        ALOGE("get ifaceIndexName map fd failed: %s", strerror(errno));
-        return ret;
-    }
-
-    BpfMapRO<uint32_t, StatsValue> ifaceStatsMap(IFACE_STATS_MAP_PATH);
-    if (!ifaceStatsMap.isValid()) {
-        ret = -errno;
-        ALOGE("get ifaceStats map fd failed: %s", strerror(errno));
-        return ret;
-    }
+    static BpfMapRO<uint32_t, IfaceValue> ifaceIndexNameMap(IFACE_INDEX_NAME_MAP_PATH);
+    static BpfMapRO<uint32_t, StatsValue> ifaceStatsMap(IFACE_STATS_MAP_PATH);
     return parseBpfNetworkStatsDevInternal(lines, ifaceStatsMap, ifaceIndexNameMap);
 }