Support active BLE scans.

Active scans send a request to the device when they have received an
advertisement.

lib/ble/ble.toit

@@ -1084,7 +1084,7 @@ ble-create-central-manager_ adapter-resource:
 ble-create-peripheral-manager_ adapter-resource bonding secure-connections:
   #primitive.ble.create-peripheral-manager
 
-ble-scan-start_ central-manager duration-us:
+ble-scan-start_ central-manager passive duration-us:
   #primitive.ble.scan-start
 
 ble-scan-next_ central-manager:

lib/ble/remote.toit

@@ -50,14 +50,19 @@ class Central extends Resource_:
 
   Only one scan can run at a time.
 
+  If $active is true, then we request a scan response from discovered devices.
+    Users might need to merge the advertisement data from the scan response with the
+    advertisement data from the discovery event. Use
+    $RemoteScannedDevice.is-scan-response to distinguish between the two.
+
   Connections cannot be established while a scan is ongoing.
 
   Stops the scan after the given $duration.
   */
-  scan [block] --duration/Duration?=null:
+  scan [block] --duration/Duration?=null --active/bool=false:
     duration-us := duration ? (max 0 duration.in-us) : -1
     resource-state_.clear-state COMPLETED-EVENT_
-    ble-scan-start_ resource_ duration-us
+    ble-scan-start_ resource_ (not active) duration-us
     is-macos := system.platform == system.PLATFORM_MACOS
     try:
       while true:

src/primitive.h

@@ -346,7 +346,7 @@ namespace toit {
   PRIMITIVE(create_central_manager, 1)       \
   PRIMITIVE(close, 1)                        \
   PRIMITIVE(release_resource, 1)             \
-  PRIMITIVE(scan_start, 2)                   \
+  PRIMITIVE(scan_start, 3)                   \
   PRIMITIVE(scan_next, 1)                    \
   PRIMITIVE(scan_stop, 1)                    \
   PRIMITIVE(connect, 3)                      \

src/resources/ble_darwin.mm

@@ -826,7 +826,7 @@ - (id)initWithResource:(toit::BleResource*)resource {
 }
 
 PRIMITIVE(scan_start) {
-  ARGS(BleCentralManagerResource, central_manager, int64, duration_us);
+  ARGS(BleCentralManagerResource, central_manager, bool, passive, int64, duration_us);
 
   Locker locker(central_manager->scan_mutex());
   bool active = [central_manager->central_manager() isScanning];

src/resources/ble_esp32.cc

@@ -2417,7 +2417,7 @@ PRIMITIVE(close) {
 }
 
 PRIMITIVE(scan_start) {
-  ARGS(BleCentralManagerResource, central_manager, int64, duration_us)
+  ARGS(BleCentralManagerResource, central_manager, bool, passive, int64, duration_us)
 
   Locker locker(central_manager->group()->mutex());
 
@@ -2440,11 +2440,7 @@ PRIMITIVE(scan_start) {
   // repeated advertisements from the same device.
   // disc_params.filter_duplicates = 1;
 
-  /**
-   * Perform a passive scan.  I.e., don't send follow-up scan requests to
-   * each advertiser.
-   */
-  disc_params.passive = 1;
+  disc_params.passive = passive ? 1 : 0;
 
   /* Use defaults for the rest of the parameters. */
   disc_params.itvl = 0;

tests/hw/esp32/ble6-advertise-shared.toit

@@ -62,24 +62,40 @@ main-peripheral:
   next-semaphore.down
   peripheral.stop-advertise
 
-  advertise := : | blocks |
+  advertise := : | blocks scan-response-blocks |
     advertisement = AdvertisementData blocks
-    peripheral.start-advertise --allow-connections advertisement
+    scan-response := scan-response-blocks
+        ? AdvertisementData scan-response-blocks
+        : null
+    peripheral.start-advertise --allow-connections advertisement --scan-response=scan-response
     next-semaphore.down
     peripheral.stop-advertise
 
-  advertise.call []
+  advertise.call [] null
   advertise.call [
-    DataBlock.flags --general-discovery --bredr-supported=false,
-    DataBlock.manufacturer-specific --company-id=COMPANY-ID MANUFACTURER-DATA,
-  ]
+      DataBlock.flags --general-discovery --bredr-supported=false,
+      DataBlock.manufacturer-specific --company-id=COMPANY-ID MANUFACTURER-DATA,
+    ]
+    null
   advertise.call [
-    DataBlock.name "Test",
-    DataBlock.services-128 [TEST-SERVICE],
-  ]
+      DataBlock.name "Test",
+      DataBlock.services-128 [TEST-SERVICE],
+    ]
+    null
   advertise.call [
-    DataBlock.manufacturer-specific (ByteArray 27: it)
-  ]
+      DataBlock.manufacturer-specific (ByteArray 27: it)
+    ]
+    null
+  advertise.call
+    [
+      DataBlock.name "Test",
+    ]
+    [  // The scan response.
+      DataBlock.services-128 [TEST-SERVICE],
+    ]
+
+
+
 
   done = true
 
@@ -100,8 +116,10 @@ test-data
     address/any
     characteristic/RemoteCharacteristic
     --central/Central
-    --is-connectable/bool=true [block]:
+    --is-connectable/bool=true
+    [block]:
   remote-scanned := scan address --central=central
+  expect-not remote-scanned.is-scan-response
   expect-equals address remote-scanned.address
   expect-equals is-connectable remote-scanned.is-connectable
   block.call remote-scanned.data
@@ -162,6 +180,31 @@ main-central:
           expect-equals (ByteArray 27: it) data
           id)
 
+  // Check that active/passive scanning works.
+  central.scan --duration=(Duration --s=2): | device/RemoteScannedDevice |
+    if device.address == address:
+      // Without doing an active scan we don't get a scan response.
+      expect-not device.is-scan-response
+
+  advertisement/AdvertisementData? := null
+  scan-response/AdvertisementData? := null
+  while true:  // Use loop to be able to break out of the block.
+    central.scan --duration=(Duration --s=3) --active: | device/RemoteScannedDevice |
+      if device.address == address:
+        if device.is-scan-response:
+          scan-response = device.data
+        else:
+          advertisement = device.data
+        if advertisement and scan-response: break
+    break
+
+  expect-equals 1 advertisement.data-blocks.size
+  expect-equals "Test" advertisement.name
+  expect-equals 1 scan-response.data-blocks.size
+  expect-equals [TEST-SERVICE] scan-response.services
+
+  characteristic.write #[central-test-counter++]
+
   remote-device.close
   central.close
   adapter.close