Support more than 8 firewall chains / match types.

In the BPF code, per-UID network access (e.g., for doze mode,
standby, etc.) is stored in UidOwnerValue structures. Each of
these stores that UID's rules in a 32-bit bitmask of
UidOwnerMatchType values, so the code can support ~31 match
types.

However, which match types are enabled is stored in
configuration_map at index UID_RULES_CONFIGURATION_KEY, and
configuration_map only stores 8-bit values. So it's not
possible to define more than 7 match types.

Widen configuration_map to from 8 to 32 bits to match the width
of UidOwnerValue.rule. This doesn't impact memory because
configuration_map only has 2 entries.

Bug: 208371987
Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I7e1eee2daedd66d27965a2dd4ce6b4c3667892f7
(cherry picked from commit 60cbed385dcf3c640674c48b7cd4d60967047cf0)
Merged-In: I7e1eee2daedd66d27965a2dd4ce6b4c3667892f7
diff --git a/bpf_progs/bpf_shared.h b/bpf_progs/bpf_shared.h
index 14fcdd6..634fbf4 100644
--- a/bpf_progs/bpf_shared.h
+++ b/bpf_progs/bpf_shared.h
@@ -147,9 +147,9 @@
     SELECT_MAP_B,
 };
 
-// TODO: change the configuration object from an 8-bit bitmask to an object with clearer
+// TODO: change the configuration object from a bitmask to an object with clearer
 // semantics, like a struct.
-typedef uint8_t BpfConfig;
+typedef uint32_t BpfConfig;
 static const BpfConfig DEFAULT_CONFIG = 0;
 
 typedef struct {
@@ -160,7 +160,9 @@
 } UidOwnerValue;
 STRUCT_SIZE(UidOwnerValue, 2 * 4);  // 8
 
+// Entry in the configuration map that stores which UID rules are enabled.
 #define UID_RULES_CONFIGURATION_KEY 1
+// Entry in the configuration map that stores which stats map is currently in use.
 #define CURRENT_STATS_MAP_CONFIGURATION_KEY 2
 
 #define BPF_CLATD_PATH "/sys/fs/bpf/net_shared/"
diff --git a/bpf_progs/netd.c b/bpf_progs/netd.c
index 33381d7..b4ef7eb 100644
--- a/bpf_progs/netd.c
+++ b/bpf_progs/netd.c
@@ -62,7 +62,7 @@
 DEFINE_BPF_MAP_GRW(stats_map_B, HASH, StatsKey, StatsValue, STATS_MAP_SIZE, AID_NET_BW_ACCT)
 DEFINE_BPF_MAP_GRW(iface_stats_map, HASH, uint32_t, StatsValue, IFACE_STATS_MAP_SIZE,
                    AID_NET_BW_ACCT)
-DEFINE_BPF_MAP_GRW(configuration_map, HASH, uint32_t, uint8_t, CONFIGURATION_MAP_SIZE,
+DEFINE_BPF_MAP_GRW(configuration_map, HASH, uint32_t, uint32_t, CONFIGURATION_MAP_SIZE,
                    AID_NET_BW_ACCT)
 DEFINE_BPF_MAP_GRW(uid_owner_map, HASH, uint32_t, UidOwnerValue, UID_OWNER_MAP_SIZE,
                    AID_NET_BW_ACCT)
@@ -234,7 +234,7 @@
 }
 
 static __always_inline inline void update_stats_with_config(struct __sk_buff* skb, int direction,
-                                                            StatsKey* key, uint8_t selectedMap) {
+                                                            StatsKey* key, uint32_t selectedMap) {
     if (selectedMap == SELECT_MAP_A) {
         update_stats_map_A(skb, direction, key);
     } else if (selectedMap == SELECT_MAP_B) {
@@ -286,7 +286,7 @@
     if (counterSet) key.counterSet = (uint32_t)*counterSet;
 
     uint32_t mapSettingKey = CURRENT_STATS_MAP_CONFIGURATION_KEY;
-    uint8_t* selectedMap = bpf_configuration_map_lookup_elem(&mapSettingKey);
+    uint32_t* selectedMap = bpf_configuration_map_lookup_elem(&mapSettingKey);
 
     // Use asm("%0 &= 1" : "+r"(match)) before return match,
     // to help kernel's bpf verifier, so that it can be 100% certain
diff --git a/netd/BpfHandler.h b/netd/BpfHandler.h
index 2ede1c1..05b9ebc 100644
--- a/netd/BpfHandler.h
+++ b/netd/BpfHandler.h
@@ -62,7 +62,7 @@
     BpfMap<uint64_t, UidTagValue> mCookieTagMap;
     BpfMap<StatsKey, StatsValue> mStatsMapA;
     BpfMap<StatsKey, StatsValue> mStatsMapB;
-    BpfMap<uint32_t, uint8_t> mConfigurationMap;
+    BpfMap<uint32_t, uint32_t> mConfigurationMap;
     BpfMap<uint32_t, uint8_t> mUidPermissionMap;
 
     std::mutex mMutex;
diff --git a/netd/BpfHandlerTest.cpp b/netd/BpfHandlerTest.cpp
index cd6b565..12ae916 100644
--- a/netd/BpfHandlerTest.cpp
+++ b/netd/BpfHandlerTest.cpp
@@ -48,7 +48,7 @@
     BpfHandler mBh;
     BpfMap<uint64_t, UidTagValue> mFakeCookieTagMap;
     BpfMap<StatsKey, StatsValue> mFakeStatsMapA;
-    BpfMap<uint32_t, uint8_t> mFakeConfigurationMap;
+    BpfMap<uint32_t, uint32_t> mFakeConfigurationMap;
     BpfMap<uint32_t, uint8_t> mFakeUidPermissionMap;
 
     void SetUp() {
diff --git a/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp b/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
index 4d605ce..9ebef4d 100644
--- a/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
+++ b/service-t/native/libs/libnetworkstats/BpfNetworkStats.cpp
@@ -193,7 +193,7 @@
         return ret;
     }
 
-    BpfMapRO<uint32_t, uint8_t> configurationMap(CONFIGURATION_MAP_PATH);
+    BpfMapRO<uint32_t, uint32_t> configurationMap(CONFIGURATION_MAP_PATH);
     if (!configurationMap.isValid()) {
         int ret = -errno;
         ALOGE("get configuration map fd failed: %s", strerror(errno));
diff --git a/service/native/TrafficController.cpp b/service/native/TrafficController.cpp
index 5581c40..70c7c34 100644
--- a/service/native/TrafficController.cpp
+++ b/service/native/TrafficController.cpp
@@ -454,15 +454,15 @@
 int TrafficController::toggleUidOwnerMap(ChildChain chain, bool enable) {
     std::lock_guard guard(mMutex);
     uint32_t key = UID_RULES_CONFIGURATION_KEY;
-    auto oldConfiguration = mConfigurationMap.readValue(key);
-    if (!oldConfiguration.ok()) {
+    auto oldConfigure = mConfigurationMap.readValue(key);
+    if (!oldConfigure.ok()) {
         ALOGE("Cannot read the old configuration from map: %s",
-              oldConfiguration.error().message().c_str());
-        return -oldConfiguration.error().code();
+              oldConfigure.error().message().c_str());
+        return -oldConfigure.error().code();
     }
     Status res;
     BpfConfig newConfiguration;
-    uint8_t match;
+    uint32_t match;
     switch (chain) {
         case DOZABLE:
             match = DOZABLE_MATCH;
@@ -483,7 +483,7 @@
             return -EINVAL;
     }
     newConfiguration =
-            enable ? (oldConfiguration.value() | match) : (oldConfiguration.value() & (~match));
+            enable ? (oldConfigure.value() | match) : (oldConfigure.value() & (~match));
     res = mConfigurationMap.writeValue(key, newConfiguration, BPF_EXIST);
     if (!isOk(res)) {
         ALOGE("Failed to toggleUidOwnerMap(%d): %s", chain, res.msg().c_str());
@@ -495,17 +495,17 @@
     std::lock_guard guard(mMutex);
 
     uint32_t key = CURRENT_STATS_MAP_CONFIGURATION_KEY;
-    auto oldConfiguration = mConfigurationMap.readValue(key);
-    if (!oldConfiguration.ok()) {
+    auto oldConfigure = mConfigurationMap.readValue(key);
+    if (!oldConfigure.ok()) {
         ALOGE("Cannot read the old configuration from map: %s",
-              oldConfiguration.error().message().c_str());
-        return Status(oldConfiguration.error().code(), oldConfiguration.error().message());
+              oldConfigure.error().message().c_str());
+        return Status(oldConfigure.error().code(), oldConfigure.error().message());
     }
 
     // Write to the configuration map to inform the kernel eBPF program to switch
     // from using one map to the other. Use flag BPF_EXIST here since the map should
     // be already populated in initMaps.
-    uint8_t newConfigure = (oldConfiguration.value() == SELECT_MAP_A) ? SELECT_MAP_B : SELECT_MAP_A;
+    uint32_t newConfigure = (oldConfigure.value() == SELECT_MAP_A) ? SELECT_MAP_B : SELECT_MAP_A;
     auto res = mConfigurationMap.writeValue(CURRENT_STATS_MAP_CONFIGURATION_KEY, newConfigure,
                                             BPF_EXIST);
     if (!res.ok()) {
diff --git a/service/native/TrafficControllerTest.cpp b/service/native/TrafficControllerTest.cpp
index ad53cb8..c44b9d6 100644
--- a/service/native/TrafficControllerTest.cpp
+++ b/service/native/TrafficControllerTest.cpp
@@ -65,7 +65,7 @@
     BpfMap<uint64_t, UidTagValue> mFakeCookieTagMap;
     BpfMap<uint32_t, StatsValue> mFakeAppUidStatsMap;
     BpfMap<StatsKey, StatsValue> mFakeStatsMapA;
-    BpfMap<uint32_t, uint8_t> mFakeConfigurationMap;
+    BpfMap<uint32_t, uint32_t> mFakeConfigurationMap;
     BpfMap<uint32_t, UidOwnerValue> mFakeUidOwnerMap;
     BpfMap<uint32_t, uint8_t> mFakeUidPermissionMap;
 
diff --git a/service/native/include/TrafficController.h b/service/native/include/TrafficController.h
index 79e75ac..d3d52e2 100644
--- a/service/native/include/TrafficController.h
+++ b/service/native/include/TrafficController.h
@@ -155,7 +155,7 @@
      *    Userspace can do scraping and cleaning job on the other one depending on the
      *    current configs.
      */
-    bpf::BpfMap<uint32_t, uint8_t> mConfigurationMap GUARDED_BY(mMutex);
+    bpf::BpfMap<uint32_t, uint32_t> mConfigurationMap GUARDED_BY(mMutex);
 
     /*
      * mUidOwnerMap: Store uids that are used for bandwidth control uid match.