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Refactor the logic of L2CAP packet handling.

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- Refactor the logic of L2CAP packet handling.
- Add a way to response empty advertisement to fail the L2CAP request immediately.
- Reduce unnessary logs.

PiperOrigin-RevId: 769506649
This commit is contained in:
Mingshiou Wu
2025-06-10 01:24:50 -07:00
committed by Copybara-Service
parent 66b13002dd
commit 75c94db1f8
2 changed files with 61 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files
internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEL2CAPConnection.m
+61 -52
View File
@@ -101,7 +101,7 @@ static NSData *PrefixLengthData(NSData *data) {
// Prefix the service ID hash.
packet = PrefixLengthData(PrefixDataWithServiceIDHash(_serviceIDHash, data));
if (_verboseLoggingEnabled) {
GNCLoggerDebug(@"[NEARBY] GNCBLEL2CAPConnection data to be sent: %@", [packet description]);
GNCLoggerDebug(@"GNCBLEL2CAPConnection data to be sent: %@", [packet description]);
}
[_stream sendData:packet
completionBlock:^(BOOL result) {
@@ -113,7 +113,7 @@ static NSData *PrefixLengthData(NSData *data) {
}
- (void)requestDataConnectionWithCompletion:(void (^)(BOOL))completion {
GNCLoggerInfo(@"[NEARBY] Sending l2cap packet request data connection");
GNCLoggerInfo(@"Sending l2cap packet request data connection");
// TODO b/399815436 - A bug is causing channel has written to the socket but the remote does not
// receive it. Add a delay to make sure the data is written to the socket. Remove the delay once
// the bug is fixed.
@@ -141,7 +141,7 @@ static NSData *PrefixLengthData(NSData *data) {
- (void)stream:(GNCBLEL2CAPStream *)stream didReceiveData:(NSData *)data {
if (_verboseLoggingEnabled) {
GNCLoggerDebug(@"[NEARBY] BLEL2CAPConnection didReceiveData, data: %@, length: %lu",
GNCLoggerDebug(@"BLEL2CAPConnection didReceiveData, data: %@, length: %lu",
[data debugDescription], data.length);
}
if (!data.length) {
@@ -193,28 +193,27 @@ static NSData *PrefixLengthData(NSData *data) {
}
bytesProcessed = realData.length + kL2CAPPacketLength;
// Validate the L2CAP packet.
// TODO: b/399815436 - Refactor the validation logic to connections layer.
if (_incomingConnection) {
if (!_handledIncomingConnectionL2CAPPacket) {
[self handleIncomingConnectionL2CAPPacketFromData:realData];
return bytesProcessed;
}
if (!_handledReceivedBLEIntroPacket) {
[self handleBLEIntroPacketFromData:realData];
return bytesProcessed;
}
} else {
if (!_handledOutgoingConnectionL2CAPPacket) {
[self handleOutgoingConnectionL2CAPPacketFromData:realData];
return bytesProcessed;
}
if ([self handleL2CAPPacketFromData:realData]) {
return bytesProcessed;
}
// TODO: b/399815436 - All BLE control packets should be handled here and not passed to
// upper layer. Need to refine the flow after refactoring.
if (_incomingConnection && !_handledReceivedBLEIntroPacket) {
[self handleBLEIntroPacketFromData:realData];
return bytesProcessed;
}
if (realData.length < _serviceIDHash.length) {
GNCLoggerError(@"Data length mismatch. Expected size: > %lu, Data: %@",
_serviceIDHash.length, realData);
return bytesProcessed;
}
// Extract the service ID prefix from each data packet and validate it.
NSUInteger prefixLength = _serviceIDHash.length;
if (![[realData subdataWithRange:NSMakeRange(0, prefixLength)] isEqual:_serviceIDHash]) {
GNCLoggerError(@"[NEARBY]: Received wrong data packet and discarded");
return bytesProcessed;
}
@@ -254,40 +253,22 @@ static NSData *PrefixLengthData(NSData *data) {
}
}
- (void)handleIncomingConnectionL2CAPPacketFromData:(NSData *)data {
- (BOOL)handleL2CAPPacketFromData:(NSData *)data {
GNCMBLEL2CAPPacket *l2capPacket = GNCMParseBLEL2CAPPacket(data);
if (!l2capPacket) {
return;
return NO;
}
switch (l2capPacket.command) {
case GNCMBLEL2CAPCommandRequestDataConnection: {
dispatch_async(_selfQueue, ^{
[_stream sendData:PrefixLengthData(GNCMGenerateBLEL2CAPPacket(
GNCMBLEL2CAPCommandResponseDataConnectionReady, nil))
completionBlock:^(BOOL result){
}];
});
_handledReceivedL2CAPRequestDataConnectionPacket = YES;
} break;
case GNCMBLEL2CAPCommandRequestAdvertisement:
case GNCMBLEL2CAPCommandRequestAdvertisementFinish:
case GNCMBLEL2CAPCommandResponseAdvertisement:
case GNCMBLEL2CAPCommandResponseServiceIdNotFound:
case GNCMBLEL2CAPCommandResponseDataConnectionReady:
case GNCMBLEL2CAPCommandResponseDataConnectionFailure:
default:
break; // fall through
}
_handledIncomingConnectionL2CAPPacket = _handledReceivedL2CAPRequestDataConnectionPacket;
}
- (void)handleOutgoingConnectionL2CAPPacketFromData:(NSData *)data {
GNCMBLEL2CAPPacket *l2capPacket = GNCMParseBLEL2CAPPacket(data);
if (!l2capPacket) {
return;
}
GNCLoggerInfo(@"Received L2CAP packet with command: %lu", l2capPacket.command);
switch (l2capPacket.command) {
case GNCMBLEL2CAPCommandResponseDataConnectionReady: {
if (_incomingConnection || _handledOutgoingConnectionL2CAPPacket) {
GNCLoggerError(@"Ignore L2CAP response data connection ready packet. "
@"incomingConnection: %d, handledOutgoingConnectionL2CAPPacket: %d",
_incomingConnection, _handledOutgoingConnectionL2CAPPacket);
break;
}
[_requestDataConnectionCondition lock];
dispatch_async(_selfQueue, ^{
[_stream sendData:PrefixLengthData(GNCMGenerateBLEFramesIntroductionPacket(_serviceIDHash))
@@ -297,9 +278,37 @@ static NSData *PrefixLengthData(NSData *data) {
}];
});
_handledReceivedL2CAPResponseDataConnectionReadyPacket = YES;
_handledOutgoingConnectionL2CAPPacket =
_handledReceivedL2CAPResponseDataConnectionReadyPacket;
} break;
case GNCMBLEL2CAPCommandRequestDataConnection: {
if (!_incomingConnection || _handledIncomingConnectionL2CAPPacket) {
GNCLoggerError(@"Ignore L2CAP request data connection packet. "
@"incomingConnection: %d, handledIncomingConnectionL2CAPPacket: %d",
_incomingConnection, _handledIncomingConnectionL2CAPPacket);
break;
}
dispatch_async(_selfQueue, ^{
[_stream sendData:PrefixLengthData(GNCMGenerateBLEL2CAPPacket(
GNCMBLEL2CAPCommandResponseDataConnectionReady, nil))
completionBlock:^(BOOL result){
}];
});
_handledReceivedL2CAPRequestDataConnectionPacket = YES;
_handledIncomingConnectionL2CAPPacket = _handledReceivedL2CAPRequestDataConnectionPacket;
} break;
case GNCMBLEL2CAPCommandRequestAdvertisement: {
// Return an empty advertisement response to fail the request immediately.
// TODO b/399815436 : Consider returning the real advertisement data in the future after
// refactoring the flow to mediums layer if we want to support it.
dispatch_async(_selfQueue, ^{
[_stream sendData:PrefixLengthData(GNCMGenerateBLEL2CAPPacket(
GNCMBLEL2CAPCommandResponseAdvertisement, nil))
completionBlock:^(BOOL result){
}];
});
} break;
case GNCMBLEL2CAPCommandRequestAdvertisement:
case GNCMBLEL2CAPCommandRequestDataConnection:
case GNCMBLEL2CAPCommandRequestAdvertisementFinish:
case GNCMBLEL2CAPCommandResponseAdvertisement:
case GNCMBLEL2CAPCommandResponseServiceIdNotFound:
@@ -307,16 +316,16 @@ static NSData *PrefixLengthData(NSData *data) {
default:
break; // fall through
}
_handledOutgoingConnectionL2CAPPacket = _handledReceivedL2CAPResponseDataConnectionReadyPacket;
return YES;
}
- (void)handleBLEIntroPacketFromData:(NSData *)data {
NSData *serviceIDHash = GNCMParseBLEFramesIntroductionPacket(data);
if ([serviceIDHash isEqual:_serviceIDHash]) {
_handledReceivedBLEIntroPacket = YES;
GNCLoggerInfo(@"[NEARBY]: Received BLE intro packet and handled.");
GNCLoggerInfo(@"Received BLE intro packet and handled.");
} else {
GNCLoggerInfo(@"[NEARBY]: Received wrong BLE intro packet and discarded.");
GNCLoggerInfo(@"Received wrong BLE intro packet and discarded.");
}
}
internal/platform/implementation/apple/Mediums/Ble/GNCMBleUtils.mm
-2
View File
@@ -116,7 +116,6 @@ NSData *GNCMGenerateBLEFramesDisconnectionPacket(NSData *serviceIDHash) {
// TODO: b/399815436 - Add unit tests for this function.
GNCMBLEL2CAPPacket *_Nullable GNCMParseBLEL2CAPPacket(NSData *data) {
if (data.length < 1) {
GNCLoggerError(@"[NEARBY] Invalid packet length: %@", @(data.length));
return nil;
}
@@ -125,7 +124,6 @@ GNCMBLEL2CAPPacket *_Nullable GNCMParseBLEL2CAPPacket(NSData *data) {
NSUInteger receivedDataLength = [data length];
GNCMBLEL2CAPCommand command = (GNCMBLEL2CAPCommand)bytes[0];
if (!IsSupportedCommand(command)) {
GNCLoggerError(@"[NEARBY] Invalid command: %lu", command);
return nil;
}