⚡ (LekaUpdater): Maximum packet size related to negotiated MTU charac…

…teristic
leka · May 29, 2024 · b7b3ae6 · b7b3ae6
1 parent 3e94fa2
commit b7b3ae6
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Showing 2 changed files with 31 additions and 14 deletions.
diff --git a/Apps/LekaUpdater/Sources/Libs/UpdateProcess/Version/UpdateProcessV150.swift b/Apps/LekaUpdater/Sources/Libs/UpdateProcess/Version/UpdateProcessV150.swift
@@ -219,10 +219,7 @@ private class StateSendingFile: GKState, StateEventProcessor {
     // MARK: Lifecycle
 
     override init() {
-        let dataSize = globalFirmwareManager.data.count
-
-        self.expectedCompletePackets = Int(floor(Double(dataSize / self.maximumPacketSize)))
-        self.expectedRemainingBytes = Int(dataSize % self.maximumPacketSize)
+        self.firmwareDataSize = globalFirmwareManager.data.count
 
         self.currentPacket = 0
 
@@ -242,7 +239,20 @@ private class StateSendingFile: GKState, StateEventProcessor {
     }
 
     override func didEnter(from _: GKState?) {
-        self.sendFile()
+        Robot.shared.connectedPeripheral?.peripheral.readValue(forCharacteristic: BLESpecs.Monitoring.Characteristics.negotiatedMTU, inService: BLESpecs.Monitoring.service)
+            .receive(on: DispatchQueue.main)
+            .sink(
+                receiveCompletion: { _ in
+                    // nothing to do
+                },
+                receiveValue: { data in
+                    if let data {
+                        self.maximumPacketSize = Int(data.map { UInt16($0) }.reduce(0) { $0 << 8 + $1 }) - self.l2capOverhead
+                        self.sendFile()
+                    }
+                }
+            )
+            .store(in: &self.cancellables)
     }
 
     override func willExit(to _: GKState) {
@@ -265,11 +275,6 @@ private class StateSendingFile: GKState, StateEventProcessor {
 
     private var cancellables: Set<AnyCancellable> = []
 
-    private let maximumPacketSize: Int = 182 // 185 (iOS max MTU) - 3 (header size)
-
-    private var currentPacket: Int = 0
-    private var expectedCompletePackets: Int
-    private var expectedRemainingBytes: Int
     private lazy var characteristic: CharacteristicModelWriteOnly? = CharacteristicModelWriteOnly(
         characteristicUUID: BLESpecs.FileExchange.Characteristics.fileReceptionBuffer,
         serviceUUID: BLESpecs.FileExchange.service,
@@ -279,6 +284,20 @@ private class StateSendingFile: GKState, StateEventProcessor {
         }
     )
 
+    private var firmwareDataSize: Int = 0
+    private let l2capOverhead: Int = 3
+    private var maximumPacketSize: Int = 182 // 185 (iOS max MTU) - 3 (header size)
+
+    private var currentPacket: Int = 0
+
+    private var expectedCompletePackets: Int {
+        Int(floor(Double(self.firmwareDataSize / self.maximumPacketSize)))
+    }
+
+    private var expectedRemainingBytes: Int {
+        self.firmwareDataSize % self.maximumPacketSize
+    }
+
     private var expectedPackets: Int {
         self.expectedRemainingBytes == 0 ? self.expectedCompletePackets : self.expectedCompletePackets + 1
     }
@@ -291,10 +310,7 @@ private class StateSendingFile: GKState, StateEventProcessor {
         globalFirmwareManager.$data
             .receive(on: DispatchQueue.main)
             .sink { data in
-                let dataSize = data.count
-
-                self.expectedCompletePackets = Int(floor(Double(dataSize / self.maximumPacketSize)))
-                self.expectedRemainingBytes = Int(dataSize % self.maximumPacketSize)
+                self.firmwareDataSize = data.count
             }
             .store(in: &self.cancellables)
     }

diff --git a/Modules/BLEKit/Sources/BLESpecs.swift b/Modules/BLEKit/Sources/BLESpecs.swift
@@ -37,6 +37,7 @@ public enum BLESpecs {
             public static let screensaverEnable = CBUUID(string: "0x8369")
             public static let softReboot = CBUUID(string: "0x8382")
             public static let hardReboot = CBUUID(string: "0x7282")
+            public static let negotiatedMTU = CBUUID(data: Data("NEGOTIATED_MTU".utf8) + Data([0, 0]))
         }
 
         public static let service = CBUUID(string: "0x7779")