Socket Problem

Actually, maybe few notes. You're using terms like listeningSocket, broadcastingSocket and using multicast join: as well, so I'm wondering if there's some confusion here. Listening here seems to refer to normal UDP socket. The broadcasting socket seems to be a multicasting socket actually, however it all depends on the actual IP addresses you're using. Broadcasting address is usually the last address in your network address space ( e.g. 192.168.1.255/24) and there's no joining or leaving. Everybody can listen in on those messages. Multicasting addresses are from the dedicated range 224... - 23?... (I don't remember the upper limit) and you need to explicitly join: and leave: a specific address. Anyway, I wonder if you've got all that lined up properly.

HTH,

Martin

Emiliano Pérez wrote:
> Hi, it´s me again, i´m still getting the problem. I´ve tried different
> solutions, and it still doesn´t works.
>
> a little more info:
>

> This is the p2p sending code:
>
>    sendPeerCommand: aCommand to: aPeerAddress
>        self listeningSocket writeWait.
>        self listeningSocket sendTo: aPeerAddress buffer: (aCommand
> encodeCommand).
>
> - if i put the writeWait before sending it gives me the
> ERROR_BAD_COMMAND from the primitive 685 coming from the writeWait.
> - if i don´t put it, it gives me the BADARGS_ERROR in the primitive 676
> coming from the sendTo:buffer: message.
>
> I emphasize the fact that the error appears only when sending an
> Acknowledgment, in other words it´s the executeOn: from a received
> command who calls the sendPeerCommand message.
>
> Any help on the "why" or the "how" of this 2 errors wold be very
> appreciated too.
> Thanks,
> Emiliano.
>
> Emiliano Pérez escribió:
>> Hello, this is my first post in this list, I´m Emiliano Pérez.
>>
>> I´m working on an service that is meant to discover other machines in
>> the LAN running the same service. This is done by an object running 2
>> threads, the first has a receiving socket on regular udp. and the
>> other has a receiving multicast (managed as a strategy) socket. The
>> broadcast socket is for detecting the other machines, and the udp
>> socket is for pear to pear communication. The sockets receive commands
>> and send acknowledgments. When i start the object it sends an "enter
>> command" to the multicast ip, so the others can "see" it and send him
>> an acknowledgment through the p2p socket. The problem comes up when
>> the local object receives an "Enter" command from himself and sends an
>> Acknowledge command to the sender (self) . When it sends that last
>> command it keeps getting a BADARGS_ERROR exception from the p2p
>> socket. To explain a little more what it is that i do i copy some
>> methods below that i hope, will help you to understand.
>> The code:
>>
>> " - the start method "
>>
>> ->start
>>    self isActive ifFalse:[
>>                            self prepareSocketAt: self listeningPort.
>>             " newUDPserverAtPort:xxxx "

>>                            self broadcastingStrategy open.

>>              " in this case a multicast socket "
>>                            self turnOn.
>>              " this method sets isActive in true "
>>                            self launchPeerThread.
>>                            self launchBroadcastingThread.
>>                            self
>> advertise.].                                       "
>> sendBroadcastCommand: EnterCommand "
>>
>> ->launchPeerThread
>>        [
>>        [self isActive] whileTrue:[ | cmd |
>>                                cmd:=self receivePeerCommand.
>>                                cmd executeOn: self.
>>                                ].
>>        self broadcastingStrategy close.] fork.
>>
>> " - the broadcast thread is the same, only receiveBroadcastCommand
>> instead of receiveBroadcastCommand ".
>>
>>
>> ->receivePeerCommand
>>
>>        | peerAddress buffer size |             buffer:=ByteArray new:
>> self defaultBufferSize.
>>        peerAddress:=IPSocketAddress new.
>>        self listeningSocket readWait.
>>        size:=self listeningSocket receiveFrom: peerAddress buffer:
>> buffer start: 1 for: buffer size.
>>        ^DiscovererCommand decodeFrom: (buffer copyFrom: 1 to: size).
>>
>> MulticastStrategy->receiveBroadcast
>>
>>    | buffer size |
>>
>>    buffer := ByteArray new: self defaultBufferSize.
>>    self broadcastingSocket readWait.
>>    size := self broadcastingSocket receiveFrom: self
>> inBroadcastingAddress
>>                buffer: buffer.
>>    ^buffer copyFrom: 1 to: size
>>
>> " this is the code that starts the multicast socket "
>>
>> MulticastStrategy->open
>>
>>    self broadcastingSocket: (SocketAccessor family: SocketAccessor
>> AF_INET
>>                type: SocketAccessor SOCK_DGRAM).
>>    self broadcastingSocket soReuseaddr: true.
>>    self broadcastingSocket bindTo: self inBroadcastingAddress.
>>    self broadcastingSocket
>>        join: (self multicastRequestFrom: self broadcastingGroup)
>>
>>
>> " this is the code that is executed when the command is received "
>>
>> EnterCommand->doExecuteOn: aReceiver
>>        aReceiver addHost: self senderAddress.
>>        aReceiver sendAcknowledgeTo: self senderAddress.
>>
>>
>> Thats the important code until i´m able to isolate the problem a bit
>> more. The error is not constant, but it appears about 60% of the times
>> when i start the object.
>>
>> Thanks in advance,
>> Emiliano.
>>
>>
>

>