Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Jack, > So when I resume, > instead of setting the option, I can still use the Resume() > function to resume notification? I'm not sure I understeand completely what you ask but: - Pause will stop notification from winsock. If there is already data received then OnDataAvailable will keep on firing for a while until you have received. After that winsock buffer will fill but no notification. When winsock buffer is full then sender will stop sending data. - Resume will turn notification back on, so filled up receive buffer from winsock will fire onDataAvailable again. - if you set wosNoReceivedLoop and you do NOT receive in OnDataAvaliable then it will also not fire again until you call receive. This means that you have to call Receive outside the OnDataAvailable to turn it on again. - A combination of both should be working also. You call pause, and when you are in paused state you dont want to receive even if there is already somethign to receive as you explained in a previous mail. Then you do the wsoNoReceivLop; I "think" if combine both, and you call Resume that OnDataAvailable will fire again without calling Receive outside of it. You can try it easely of course. Pleas let us know, this is valuable information. --- Rgds, Wilfried [TeamICS] http://www.overbyte.be/eng/overbyte/teamics.html http://www.mestdagh.biz -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Francois, Thanks for the reply. I'll try that. So when I resume, instead of setting the option, I can still use the Resume() function to resume notification? -- Best regards, Jack Sunday, February 19, 2006, 2:20:54 AM, you wrote: >> I find that calling pause in OnSessionConnected() is effective. >> But calling pause in OnClientDataAvailable() does not work. >> OnClientDataAvailable() keeps getting fired. Any ideas? > Maybe your socket already received data when you pause it. > Pause only affect winsock notification. It stops notifications from winsock > but if data is already in, you have to read it. > Try the option wsoNoReceiveLoop, it may help to stop delivering of already > received data. If you use the option and pause the socket, you will not be > notified of any data already received and waiting in the buffer. So when you > resume, you should probably call Receive once to check for remaining data. > -- > Contribute to the SSL Effort. Visit > http://www.overbyte.be/eng/ssl.html > -- > [EMAIL PROTECTED] > http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
> I find that calling pause in OnSessionConnected() is effective. > But calling pause in OnClientDataAvailable() does not work. > OnClientDataAvailable() keeps getting fired. Any ideas? Maybe your socket already received data when you pause it. Pause only affect winsock notification. It stops notifications from winsock but if data is already in, you have to read it. Try the option wsoNoReceiveLoop, it may help to stop delivering of already received data. If you use the option and pause the socket, you will not be notified of any data already received and waiting in the buffer. So when you resume, you should probably call Receive once to check for remaining data. -- Contribute to the SSL Effort. Visit http://www.overbyte.be/eng/ssl.html -- [EMAIL PROTECTED] http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Jack wrote: > Hello Francois, > > I find that calling pause in OnSessionConnected() is effective. > But calling pause in OnClientDataAvailable() does not work. > OnClientDataAvailable() keeps getting fired. Any ideas? You may have paused the server socket instead of the TWSocketClient? Arno Garrels > -- > Best regards, > Jack > > Sunday, January 22, 2006, 10:33:21 AM, you wrote: > Maybe use Pause/Resume ? >>> >>> Oh, I didn't even know these two methods. So Pause will stop >>> all network connectivity on that socket until it's resumed? > >> It suppress async notification. So you don't receive events anymore but >> I/O continue as much as winsock can, for example filling his receive >> buffer. -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Francois, I find that calling pause in OnSessionConnected() is effective. But calling pause in OnClientDataAvailable() does not work. OnClientDataAvailable() keeps getting fired. Any ideas? -- Best regards, Jack Sunday, January 22, 2006, 10:33:21 AM, you wrote: >>> Maybe use Pause/Resume ? >> >> Oh, I didn't even know these two methods. So Pause will stop >> all network connectivity on that socket until it's resumed? > It suppress async notification. So you don't receive events anymore but I/O > continue as much as winsock can, for example filling his receive buffer. -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Francois, > You can't ignore OnDataavailable event ! Got it. >> > There is a flag FPaused but it is not exposed as a property. >> Oh, will you be able to expose it? I can modify the source >> code for now but I think it's useful when Pause and Resume >> is exposed. > Not really. You can have a flag set/reset in your own application > when you call Pause/Resume, or you > can derive from TWSocket and create the property in your derived > component. That's what OOP is all about. Hmm. Is there any particular reason that you don't want to expose FPaused? It seems safe to call Resume on all client socket without checking, am I right? Thanks, Jack -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
> >>> Maybe use Pause/Resume ? > > > It suppress async notification. So you don't receive events anymore but I/O > > continue as much as winsock can, for example filling his receive buffer. > > Got it. Wouldn't this be similar to ignoring OnDataAvailable event You can't ignore OnDataavailable event ! If you don't call Receive from OnDataAvailable event, the event will be triggered again and again until you read the data. You'll enter an infinite loop. Calling Pause will stop OnDataAvailable from being triggered, this is different. > and is vulnerable to DOS attack? Whan paused, a socket will still accept some data, until winsock buffer is full. Then transmission will be stopped until you resume the socket. At that time, you'll start to receive data again (OnDataAvailable will be triggered again). You application has full control about what data is sent and can detect anormal traffic and close the connection. > > There is a flag FPaused but it is not exposed as a property. > > Oh, will you be able to expose it? I can modify the source > code for now but I think it's useful when Pause and Resume > is exposed. Not really. You can have a flag set/reset in your own application when you call Pause/Resume, or you can derive from TWSocket and create the property in your derived component. That's what OOP is all about. -- Contribute to the SSL Effort. Visit http://www.overbyte.be/eng/ssl.html -- [EMAIL PROTECTED] Author of ICS (Internet Component Suite, freeware) Author of MidWare (Multi-tier framework, freeware) http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Jack, >> It suppress async notification. So you don't receive events anymore but I/O >> continue as much as winsock can, for example filling his receive buffer. > Got it. Wouldn't this be similar to ignoring OnDataAvailable event > and is vulnerable to DOS attack? If you call Pauze then winsock will stay receiving until his buffer is full. Default value is 8 KB. Later when you wants to receive again and call Resume all is back to normal. DOS attac will only grow until winsock buffer is full so not a big deal (8 KB). --- Rgds, Wilfried [TeamICS] http://www.overbyte.be/eng/overbyte/teamics.html http://www.mestdagh.biz -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Jack, > if there is data available but do not want to actually remove > the data from twsocket's buffer. This is because I want to You can use Pauze / Resume but there is also a very simple way to do it, just set wsoNoReceiveLoop in SocketOptions to True and dont Receive in OnDataAvailable, just Exit. At that point OnDataAvailable will not fire again. Later when you wants to receive again, just call Receive outside OnDataAvailable. --- Rgds, Wilfried [TeamICS] http://www.overbyte.be/eng/overbyte/teamics.html http://www.mestdagh.biz -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Francois, >>> Maybe use Pause/Resume ? > It suppress async notification. So you don't receive events anymore but I/O > continue as much as winsock can, for example filling his receive buffer. Got it. Wouldn't this be similar to ignoring OnDataAvailable event and is vulnerable to DOS attack? >> If so, I guess I Pause the client socket and resume it when >> the resume socket is connected. > Not sure I understand, but probably the answer is yes :-) Sorry for the typo. I meant remote, not resume ;) and you guess is right :) >> Is there a flat to check if a client socket is paused? > There is a flag FPaused but it is not exposed as a property. Oh, will you be able to expose it? I can modify the source code for now but I think it's useful when Pause and Resume is exposed. And sorry for the typo again. I meant flag, not flat. You got that right, too :) Jack -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
>> Maybe use Pause/Resume ? > > Oh, I didn't even know these two methods. So Pause will stop > all network connectivity on that socket until it's resumed? It suppress async notification. So you don't receive events anymore but I/O continue as much as winsock can, for example filling his receive buffer. > If so, I guess I Pause the client socket and resume it when > the resume socket is connected. Not sure I understand, but probably the answer is yes :-) > Is there a flat to check if a client socket is paused? There is a flag FPaused but it is not exposed as a property. -- Contribute to the SSL Effort. Visit http://www.overbyte.be/eng/ssl.html -- [EMAIL PROTECTED] http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Francois, >> At some point I'd like to know >> if there is data available but do not want to actually remove >> the data from twsocket's buffer. This is because I want to >> open a remote socket and make sure it's in wsConnected state, >> then I'll retrieve data and send it through the remote socket. >> The idea is to skip OnDataAvailable if no data is available, >> and when there is some data, connect to a remote server, skip >> more OnDataAvailable until the remote socket is connected, then >> actually retrieve data and send the data via remote socket. > Maybe use Pause/Resume ? Oh, I didn't even know these two methods. So Pause will stop all network connectivity on that socket until it's resumed? If so, I guess I Pause the client socket and resume it when the resume socket is connected. Is there a flat to check if a client socket is paused? > You could receive a lot of data before the other socket is opened. This is a > potential DOS attack. This is a good point. Thanks, Jack -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
> Is there a way to tell the number of bytes available without > actually retrieving the data? There is RcvdCount but due to winsock limitation, it is not always accurate. > At some point I'd like to know > if there is data available but do not want to actually remove > the data from twsocket's buffer. This is because I want to > open a remote socket and make sure it's in wsConnected state, > then I'll retrieve data and send it through the remote socket. > The idea is to skip OnDataAvailable if no data is available, > and when there is some data, connect to a remote server, skip > more OnDataAvailable until the remote socket is connected, then > actually retrieve data and send the data via remote socket. > > Or is it a bad idea to do so? Maybe use Pause/Resume ? > An alternative way is to call Receive() and allocate memory > and cache the data into memory before remote socket is available. > But is this necessary? You could receive a lot of data before the other socket is opened. This is a potential DOS attack. -- Contribute to the SSL Effort. Visit http://www.overbyte.be/eng/ssl.html -- [EMAIL PROTECTED] http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Hello Francois, Is there a way to tell the number of bytes available without actually retrieving the data? At some point I'd like to know if there is data available but do not want to actually remove the data from twsocket's buffer. This is because I want to open a remote socket and make sure it's in wsConnected state, then I'll retrieve data and send it through the remote socket. The idea is to skip OnDataAvailable if no data is available, and when there is some data, connect to a remote server, skip more OnDataAvailable until the remote socket is connected, then actually retrieve data and send the data via remote socket. Or is it a bad idea to do so? An alternative way is to call Receive() and allocate memory and cache the data into memory before remote socket is available. But is this necessary? -- Best regards, Jack Sunday, January 22, 2006, 4:24:57 AM, you wrote: > Instead of ReceiveStr, call Receive to be able to get winsock.recv return > code. This return code is -1 if some error occure, 0 is remote has > gracefully closed or a positive integer to telle how many bytes you have > received. > Usually you can safely ignore any OnDataAvailable where Receive return <= 0. > -- > Contribute to the SSL Effort. Visit > http://www.overbyte.be/eng/ssl.html > -- > [EMAIL PROTECTED] > http://www.overbyte.be > - Original Message - > From: "Jack" <[EMAIL PROTECTED]> > To: > Sent: Sunday, January 22, 2006 5:25 AM > Subject: [twsocket] OnDataAvailable called before shutdown with no data >> Hello Francois and all, >> >> I use telnet as client to connect to a twsocketserver, >> after connecting to it, without sending any data from >> the client (do not type anything in telnet) I call shutdown(1) >> on all the client sockets. After this, although there is no >> data received, the client socket's OnDataAvailable is called. >> But if I call ReceiveStr(), I got data length 0. >> >> Is this a bug - because there's actually no data received? >> >> If it's not a bug, is there a way to tell if there is any >> data before calling ReceiveStr() or Receive()? >> >> -- >> Best regards, >> Jack >> >> -- >> To unsubscribe or change your settings for TWSocket mailing list >> please goto http://www.elists.org/mailman/listinfo/twsocket >> Visit our website at http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] OnDataAvailable called before shutdown with no data
Instead of ReceiveStr, call Receive to be able to get winsock.recv return code. This return code is -1 if some error occure, 0 is remote has gracefully closed or a positive integer to telle how many bytes you have received. Usually you can safely ignore any OnDataAvailable where Receive return <= 0. -- Contribute to the SSL Effort. Visit http://www.overbyte.be/eng/ssl.html -- [EMAIL PROTECTED] http://www.overbyte.be - Original Message - From: "Jack" <[EMAIL PROTECTED]> To: Sent: Sunday, January 22, 2006 5:25 AM Subject: [twsocket] OnDataAvailable called before shutdown with no data > Hello Francois and all, > > I use telnet as client to connect to a twsocketserver, > after connecting to it, without sending any data from > the client (do not type anything in telnet) I call shutdown(1) > on all the client sockets. After this, although there is no > data received, the client socket's OnDataAvailable is called. > But if I call ReceiveStr(), I got data length 0. > > Is this a bug - because there's actually no data received? > > If it's not a bug, is there a way to tell if there is any > data before calling ReceiveStr() or Receive()? > > -- > Best regards, > Jack > > -- > To unsubscribe or change your settings for TWSocket mailing list > please goto http://www.elists.org/mailman/listinfo/twsocket > Visit our website at http://www.overbyte.be -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
