NSInputStream无法从TCP连接读取[TCP-Server]

Question

I created a TCP server using this (quite old) example by Apple . My server is up and running, listening on the specified Port for incoming connections.

Everything looks perfect, my client app can connect to the server and -stream:handleEvent: is called as expected.

But when I now write to the stream, the server kind of rejects my connection. The client says that 30 Bytes has been written successfully.

But my logs say:

did read 0 Bytes from inputStream.
data received: 
NSStreamEventErrorOccurred
Error: Error Domain=NSPOSIXErrorDomain code=14 "The operation couldn't be completed. Bad address"

In the client side I'm using following code to establish the connection:

CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"10.0.10.40", 58896, &readStream, &writeStream);

_iStream = (__bridge NSInputStream *)readStream;
_oStream = (__bridge NSOutputStream *)writeStream;

[_iStream setDelegate:self];
[_oStream setDelegate:self];

[_iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[_oStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];

[_iStream open];
[_oStream open];

On the server side this creates the socket (a CFSocketCallBack is provided)

_IPv4Socket = CFSocketCreate(kCFAllocatorDefault, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketAcceptCallBack, (CFSocketCallBack)&JWTCPServerAcceptCallBack, nil);

Then in the callback I'm pairing using this:

CFStreamCreatePairWithSocket(kCFAllocatorDefault, nativeSocketHandle, &readStream, &writeStream);
CFReadStreamSetProperty(readStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);

And then bridge cast the streams to NSStreams, set the delegate, schedule in in current runloop and open them.

I'm not quite sure why this can happen so I don't provide the whole server code here. It would be simply too much.

When you need a specific piece of code or guess where it could be caused, I'll post the respective code here.

UPDATE

I now did a lot of research in my own code. I tracked the issue down to my -stream:handleEvent method invocation.

- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode {
    uint8_t *buffer = NULL;
    NSMutableData *receivedData;

    switch(eventCode) {
        case NSStreamEventHasBytesAvailable:

        if(aStream == _iStream) {
            receivedData = [NSMutableData data];

            while([_iStream read:buffer maxLength:1] > 0) {
            //    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ THIS RETURNS -1
                if([[[NSString alloc] initWithBytes:buffer length:sizeof(buffer) encoding:NSUTF8StringEncoding] isEqualToString:@"\n"]) {
                    break;
                }

                [receivedData appendBytes:buffer length:sizeof(buffer)];
            }

             NSLog(@"Did receive %li Bytes of data: %@", [receivedData length], [[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding]);
        } 
    }
}

UPDATE 2

I read this great Apple Article about TCP Servers and clients. I walked through all the steps and my program is almost identical with the code provided by Apple. The problem remains.

Answer 1

I found the solution! Actually I was declaring the buffer completely wrong. So the address meant by the error message wasn't a network address, as I thought...

uint8_t *buffer = NULL;

must be turned into

uint8_t buffer[1];