wifi: Add link layer stats API wrappers in WifiLegacyHal

Adds wrappers over the legacy HAL API for the following:
1. enable/disable link layer stats collection.
2. fetch link layer stats.

Note: Link layer stats structure is quite ugly. The wrapper stucture
declared here (LinkLayerStats) tries to separate out the pointer
elements and ignore the unnecessary variable size elements from them.

Bug: 31991459
Test: Compiles
Change-Id: I7c4188115786542866c7be56cf9f116b3f78e6a3

2 files changed, 87 insertions, 0 deletions

diff --git a/wifi/1.0/default/wifi_legacy_hal.cpp b/wifi/1.0/default/wifi_legacy_hal.cpp
index cb4d9d45cd..15b6bfc74f 100644
--- a/wifi/1.0/default/wifi_legacy_hal.cpp
+++ b/wifi/1.0/default/wifi_legacy_hal.cpp
@@ -35,6 +35,7 @@ namespace legacy_hal {
 static constexpr uint32_t kMaxVersionStringLength = 256;
 static constexpr uint32_t kMaxCachedGscanResults = 64;
 static constexpr uint32_t kMaxGscanFrequenciesForBand = 64;
+static constexpr uint32_t kLinkLayerStatsDataMpduSizeThreshold = 128;
 
 // Legacy HAL functions accept "C" style function pointers, so use global
 // functions to pass to the legacy HAL function and store the corresponding
@@ -83,6 +84,19 @@ void onGscanFullResult(wifi_request_id id,
   }
 }
 
+// Callback to be invoked for link layer stats results.
+std::function<void((wifi_request_id, wifi_iface_stat*, int, wifi_radio_stat*))>
+    on_link_layer_stats_result_internal_callback;
+void onLinkLayerStatsDataResult(wifi_request_id id,
+                                wifi_iface_stat* iface_stat,
+                                int num_radios,
+                                wifi_radio_stat* radio_stat) {
+  if (on_link_layer_stats_result_internal_callback) {
+    on_link_layer_stats_result_internal_callback(
+        id, iface_stat, num_radios, radio_stat);
+  }
+}
+
 // End of the free-standing "C" style callbacks.
 
 WifiLegacyHal::WifiLegacyHal()
@@ -335,6 +349,59 @@ WifiLegacyHal::getValidFrequenciesForGscan(wifi_band band) {
   return {status, std::move(freqs)};
 }
 
+wifi_error WifiLegacyHal::enableLinkLayerStats(bool debug) {
+  wifi_link_layer_params params;
+  params.mpdu_size_threshold = kLinkLayerStatsDataMpduSizeThreshold;
+  params.aggressive_statistics_gathering = debug;
+  return global_func_table_.wifi_set_link_stats(wlan_interface_handle_, params);
+}
+
+wifi_error WifiLegacyHal::disableLinkLayerStats() {
+  // TODO: Do we care about these responses?
+  uint32_t clear_mask_rsp;
+  uint8_t stop_rsp;
+  return global_func_table_.wifi_clear_link_stats(
+      wlan_interface_handle_, 0xFFFFFFFF, &clear_mask_rsp, 1, &stop_rsp);
+}
+
+std::pair<wifi_error, LinkLayerStats> WifiLegacyHal::getLinkLayerStats() {
+  LinkLayerStats link_stats{};
+  LinkLayerStats* link_stats_ptr = &link_stats;
+
+  on_link_layer_stats_result_internal_callback = [&link_stats_ptr](
+      wifi_request_id /* id */,
+      wifi_iface_stat* iface_stats_ptr,
+      int num_radios,
+      wifi_radio_stat* radio_stats_ptr) {
+    if (iface_stats_ptr != nullptr) {
+      link_stats_ptr->iface = *iface_stats_ptr;
+      link_stats_ptr->iface.num_peers = 0;
+    } else {
+      LOG(ERROR) << "Invalid iface stats in link layer stats";
+    }
+    if (num_radios == 1 && radio_stats_ptr != nullptr) {
+      link_stats_ptr->radio = *radio_stats_ptr;
+      // Copy over the tx level array to the separate vector.
+      if (radio_stats_ptr->num_tx_levels > 0 &&
+          radio_stats_ptr->tx_time_per_levels != nullptr) {
+        link_stats_ptr->radio_tx_time_per_levels.assign(
+            radio_stats_ptr->tx_time_per_levels,
+            radio_stats_ptr->tx_time_per_levels +
+                radio_stats_ptr->num_tx_levels);
+      }
+      link_stats_ptr->radio.num_tx_levels = 0;
+      link_stats_ptr->radio.tx_time_per_levels = nullptr;
+    } else {
+      LOG(ERROR) << "Invalid radio stats in link layer stats";
+    }
+  };
+
+  wifi_error status = global_func_table_.wifi_get_link_stats(
+      0, wlan_interface_handle_, {onLinkLayerStatsDataResult});
+  on_link_layer_stats_result_internal_callback = nullptr;
+  return {status, link_stats};
+}
+
 wifi_error WifiLegacyHal::retrieveWlanInterfaceHandle() {
   const std::string& ifname_to_find = getStaIfaceName();
   wifi_interface_handle* iface_handles = nullptr;
@@ -411,6 +478,7 @@ void WifiLegacyHal::invalidate() {
   on_firmware_memory_dump_internal_callback = nullptr;
   on_gscan_event_internal_callback = nullptr;
   on_gscan_full_result_internal_callback = nullptr;
+  on_link_layer_stats_result_internal_callback = nullptr;
 }
 
 }  // namespace legacy_hal
diff --git a/wifi/1.0/default/wifi_legacy_hal.h b/wifi/1.0/default/wifi_legacy_hal.h
index 4026834e1f..df1c3d6cea 100644
--- a/wifi/1.0/default/wifi_legacy_hal.h
+++ b/wifi/1.0/default/wifi_legacy_hal.h
@@ -39,6 +39,21 @@ struct PacketFilterCapabilities {
   uint32_t max_len;
 };
 
+// WARNING: We don't care about the variable sized members of either
+// |wifi_iface_stat|, |wifi_radio_stat| structures. So, using the pragma
+// to escape the compiler warnings regarding this.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wgnu-variable-sized-type-not-at-end"
+// The |wifi_radio_stat.tx_time_per_levels| stats is provided as a pointer in
+// |wifi_radio_stat| structure in the legacy HAL API. Separate that out
+// into a separate return element to avoid passing pointers around.
+struct LinkLayerStats {
+  wifi_iface_stat iface;
+  wifi_radio_stat radio;
+  std::vector<uint32_t> radio_tx_time_per_levels;
+};
+#pragma GCC diagnostic pop
+
 // Full scan results contain IE info and are hence passed by reference, to
 // preserve the variable length array member |ie_data|. Callee must not retain
 // the pointer.
@@ -96,6 +111,10 @@ class WifiLegacyHal {
   wifi_error stopGscan(wifi_request_id id);
   std::pair<wifi_error, std::vector<uint32_t>> getValidFrequenciesForGscan(
       wifi_band band);
+  // Link layer stats functions.
+  wifi_error enableLinkLayerStats(bool debug);
+  wifi_error disableLinkLayerStats();
+  std::pair<wifi_error, LinkLayerStats> getLinkLayerStats();
 
  private:
   // Retrieve the interface handle to be used for the "wlan" interface.