I need to send files (*.zip, *.jpg, *.xml etc) from Windows CE 5.0 device to a server via GPRS.
What are the options of sending files across to server?
I have been successful in sending some data using AT commands of Hayes compatible modem
AT-Command Interpreter ready
AT+CGDCONT=1,"IP","AIRTELGPRS.COM"
OK
AT%ETCPIP
OK
AT%ETCPIP?
%ETCPIP:1,"117.98.182.100",,"202.56.250.5","202.56.230.5"
OK
AT%OPEN="TCP","59.182.32.235",8001
CONNECT
AT%IOMODE=1
OK
AT%IPSEND="11"
%IPSEND:1,15
OK
However there is no command for sending files.
I'd use webservice on the server side and call the web service from client application - I think that you can do http requests from any common programming language/framework that targets WinCE.
It sounds like you are way to low in the stack. The AT commands you quoted are commands sent directly to the modem/module via serial/usb. You're setting up the APN and it looks like some simple TCP packet transmission.
You need to build a ppp session (DUN - dial-up networking session) to get the IP connectivity that will allow you to send files via common internet protocols like HTTP/FTP etc.
Typically once you've setup the APN in the first cid of the context you dial it via 'AT*99***1#'. This will enable the modem as a PPP endpoint. Keep in mind this can vary between modems.
Related
I have several smart devices that run Windows CE5 with our application written in .NETCF 3.5. The smart devices are connected to the internet with integrated GPRS modems. My clients would like a remote support option but VNC and similar tools doesn't seem to be able to do the job. I found several issues with VNC to get it to work. First it has severe performance issues when ran on the smart device. The second issue is that the internet provider has a firewall that blocks all incoming requests if they didn't originate from the smart device itself. Therefore I cannot initiate a remote desktop session with the smart devices since the request didn't originate from the smart device.
We could get our own APN however they are too expensive and the monthly cost is too great for the amount of smart devices we have deployed. It's more economical for us if we could add development costs to the initial product cost because our customers dislike high monthly costs and rather pay a large sum up front instead. A remote support solution would also allow us to minimize our onsite support.
That's why we more or less decided to roll our own remote desktop solution. We have code for capturing images on the smart device and only get the data that has changed since the last cycle. What we need is to make a communication solution like logmein.com (doesn't support WinCE5) where the smart devices connect to a server from which we then can stream the data to our support personnel's clients. Basically the smart device initiates a connection to our server and start delivering screen data when the server requests it. A support client connects to the server and gets a list of available streams and then select one to listen in on.
Any suggestions for how to do it considering we have to do the solution in .NETCF 3.5 on the smart devices? We have limited communication experience beyond simple soap web-services.
Since you're asking for a suggestion, I'll suggest this:
Don't reinvent. Reuse whatever you can. You can perform tunneling with SSH, so make an SSH connection (say, a port of PuTTY or plink, inside a loop) out via GPRS on your smart device; forward remote ports to local ports, bound to the SSH server's local address (127.0.0.1 (sshd):4567 => localhost (smart_device_01):4567). Your clients connect to your SSH server and access the assigned port for each device.
With that said, that's probably not the answer you're looking for. Below - the answer you're probably looking for.
Based on my analysis of how LogMeIn works, you'll want to make an HTTPS or TLS server where your smart devices will push data. Let's call it your tunnel server.
You'll probably want to spawn a new thread that repeatedly attempts to make connections to the tunnel server (outbound connections from smart device to the server, per your specified requirement). With a protocol like BEEP/BXXP, you can encapsulate and multiplex message-oriented or stream-oriented sessions. Wrap BXXP/BEEP into TLS, and tunnel through to your tunnel server. BEEP lets you multiplex streams onto one connection -- if you want the full capabilities of an in-house LogMeIn solution, you'll want to use something like this.
Once a connection is established, make a new BEEP session. With the new session, tell the tunnel server your system identification information (device name, device authentication signature). Write heartbeat data (timestamp periodically) into this new session.
Set up a callback (or another thread) which interfaces to your BEEP control session. Watch for a message requesting service. When such a request comes in, spawn the required threads to copy data from your custom remote-display protocol and push this data back through the same channel.
This sets the basic premise for your Smart Device's program. You can add functionality to this as you desire, say, to match what LMI's IT Reach subscription provides (remote registry, secure tunneled Telnet, remote filesystem, remote printing, remote sound... you get the idea)
I'll make some assumptions that you know how to properly secure all this stuff for authentication and authorization for your clients (Is user foo allowed to access smart device bar?).
On your tunnel server, start a server socket (listening for inbound connections, or from the perspective of smart devices, smart device outbound connections) that demultiplexes connections and sessions. Once a connection is opened, fire up BEEP and register a callback / start a thread to wait for the authentication/heartbeat session. Perform the required checks for AAA to smart devices -- are these devices allowed, are they known, how much does it cost, etc. Your tunnel server forwards data on behalf of your smart devices. For each BEEP session, attach a name (device name) to the BEEP session after the AAA procedures succeed; on failure, close the connection and let the AAA mechanism know (to block attackers). Your tunnel server should also set up what's required for interacting with the frontend -- that is, it should have the code to interact with BEEP to demultiplex the stream for your remote display data.
On your frontend server (can be the same box as the tunnel server), install the routine for AAA -- check if the user is known, if the user is allowed, how much the user should be charged, etc. Once all the checks are passed, make a secured connection from the frontend server to tunnel server. Get the device names that the tunnel server knows that the user is allowed to access. At this point, you should be able to get a "plaintext" stream, based on the device name, from the tunnel server. Forward this stream back to the user (via TLS, for example, or again via BEEP over TLS), or send the required configuration for your remote display client to connect to your tunnel server with the required parameters to access the remote display protocol's stream.
I want to establish a UDP Connection from a terminal device to My App On Cloud Foundry.
all output from applications on Cloud Foundry is delivered by proxy via a web server (nginx) and as far as I know only http and https are open.
Perhaps you should look at alternative ways of communicating with your console application, what kind of communication are you trying to achieve?
Using the CF_HOST:UDP_PORT from your terminal device should be OK. I suppose that an application (Java, Perl, etc) is deployed on your terminal device and on the CF server an application with a UDP channel is deployed.
This is an old post but i've had a similar problem when porting my app to pivotal's cloud foundry platform.
Turns out you can continue to use tcp or udp for any outgoing traffic without doing any special configuration (e.g. service binding, etc) but only http or https for incoming traffic. However, there is an interesting workaround proposed here
Could someone please help me to configure UDP in web server to accept connection from GPRS mobile device. The GPRS mobile device will send data packets which i need to write as a file in web server to process a web page. Please help.
i need to know the following:
1) How to configure UDP in web server
2) How can a GPRS mobile device get connected to the server using UDP
3) Write the data packets to a txt file
Please help.
A "web server" usually means am "http-server", which is a process listening for incoming "http"-requests.
Now http is a protocol that is standardized to be accessed via TCP/IP port 80.
Therefore most webserver implementations will implement a TCP/IP server that listens to port 80 by default. Usually you can change the port if need be, but usually you cannot change the transport layer to e.g. UDP.
Therefore it might not really be possible to make your "web-server" react on UDP packets.
If, however, by "web server" you mean a host accesible on the internet (that eventually might happen to run an http-daemon), you might have more luck: simply run a small server-application on that machine that listens to incoming UDP traffic on a given port, and do "something" with it (e.g. forward it to an http-daemon to display the current location)
Answers to your 3 questions:
Creating a small application listening on UDP-traffic:
a trivial server could be:
`netcat -l -u -p 8888`
This will create a UDP-server listening on port 8888, using netcat.
Whatever client connects to your server, everything that the client sends to the server will be output via stdout, and you can talk back to the client via stdin.
You shouldn't use netcat in a production environment; but it is a good and simple tool to check whether a connetion can be established and whether the protocol works.
In production, you will probably want to use a "real" UDP-server, e.g. by writing your own in the language of your choice.
How to make your gprs device talk to your server? This is impossible to answer without knowing more about the device, it's OS and the software installed that produces the data and is supposed to send it to the.
netcat -l -u -p 8888 > myfile.txt
Not sure if i'm really up-to-date, but i'm looking in a way to convert my existing project to use HTML5 websockets.
Here's my situation :
- Client runs a modified java vnc applet with extra parameter (CONNECT).
- Modified stunnel listenin on webserver (with both public, private IP) port 443
- Client connects to 443 and sends (prior to RFB) a HTTP packet like :
'CONNECT 10.0.0.1:4001'
- Stunnel opens a new stream to 10.0.0.1:4001 using SSL wrapper
- VNC Server (#10.0.0.1:4001) responds, connection is established.
Now I want to get rid of the Java Applet and switch to Websocket using NoVNC.
I want to be able to :
- Open a single port on the webserver (HTTPS preferably)
- Have client connect using HTML5 only (no more java applet)
I cannot change :
- VNCServer will still be listening on private LAN only.
- VNCServer will still listen to a bunch of ports, each corresponding to
a virtual server
Questions are :
- How to give NoVNC the notion of target HOST:PORT ?
- Is stunnel still be usable ? Or should I change to websocket proxy ?
If anyone has a starting point, i'd really appreciate !
Disclaimer: I created noVNC so my answer may be heavily biased ;-)
I'll answer you second question first:
stunnel cannot be used directly by noVNC. The issue is that the WebSockets protocol has an HTTP-like initial handshake and the messages are framed. In addition, until binary payload support is added to WebSockets, the payload is base64 encoded by the websockets proxy (websockify). Adding the necessary support to stunnel would be non-trivial but certainly doable. In fact noVNC issue #37 is an aspirational feature to add this support to stunnel.
First question:
noVNC already has a concept of HOST:PORT via the RFB.connect(host, port, password) method. The file vnc_auto.html at the top level shows how to get noVNC to automatically connect on page load based on the host, port and password specified as URL query string parameters.
However, I think what you are really asking is how do you get noVNC to connect to alternate VNC server ports on the backend. This problem is not directly addressed by noVNC and websockify. There are several ways to solve this and it usually involves an out-of-band setup/authorization mechanism so that the proxy can't be used to launch attacks by arbitrary hosts. For example, at my company we have a web based management framework that integrates noVNC and when the user wants to connect to the console, an authenticated AJAX call is used to configure the proxy for that particular user and the system they want to connect to. Our web management interface is internal only.
Ganeti Web Manager uses a similar model and the source is available. They have a fork of VNCAuthProxy that has WebSockets support. They use a control channel from the web interface to the VNCAuthProxy to setup a temporary password associated with a specific VNC server host:port.
Also OpenStack (Nova) integrates noVNC uses a similar out-of-band token based model to allow access with their nova-vncproxy.
Some links:
Ganeti Web Manager
Wiki page about how noVNC works in Ganeti Web Manager
Ganeti Web Manager sources
Ganeti Web Manager VNCAUthProxy sources
Using noVNC in Nova/OpenStack
OpenStack fork of noVNC
Old nova-vnc-proxy code
Current nova vnc proxy code
In my office building we have laptops on multiple floors all running a WCF Service. When WCF services communicate with each other, will a message for an out-of-range device automatically reach it by multi-hopping? Does WCF/the WLAN device driver handle this? Or do I have to detect if a device is not contactable/out-of-range and implement hopping in my own service?
As long as you have a connection from your WCF client to the service - yes, all avenues will be used. You shouldn't have to concern yourself with things like what network path your messages take - the network just has to be present and stable for the duration of a call ;-)
There's nothing in WCF to deal with this, really - this should be handled way lower in the network stack, by the driver or the OS.
Short answer
With WCF can do either or both of these:
Rely on an underlying protocol like IP to handle roaming
Use custom channel code that handles retries, roaming, etc the way you want it
No special mechanism for enhancing roaming is provided in the WCF classes Microsoft provides, but the framework itself is easily capable of supporting this seamlessly if you write or find a channel implementation to do this.
Full answer
WCF is not an on-the-wire protocol. It is a framework that allows you to communicate using a wide variety of protocols and network stacks. This allows you to use the same client and server code whether you are using HTTPS, raw TCP, named pipes, or any other protocol.
WCF ships with many channels in the box, and you can add your own. For example if you want to communicate over BlueTooth or IRDA, just create a new channel that talks these protocols and you can use your WCF services over it. These channels can also be found online or purchased from vendors.
Most networking today is done using the IP protocol, and if you are using WCF to communicate between desktop machines you will probably be using some protocol(s) on top of IP, for example TCP or HTTP. In this case, IP's normal routing rules will be used, so if the two machines can exchane IP packets you can communicate using WCF.
So if your WiFi access points allow seamless roaming you will be able to tap into that functionality using WCF.
If your WiFi routing doesn't have seamless roaming, you will have to do some extra work if you want to maintain a connection during roaming. Specifically you will need to create a channel that will respond to a closed connetion by re-resolving the server nane and retrying the request. Of course you will have to use DNS or another protocol so the server can update its registration as its IP address changes.
WCF is flexible enough to allow you to create such a channel and use it without your application code ever realizing it. But nothing like this comes in the box: You would have to build it, or download or purchase it.
it has nothing to do with WCF....
if there is a connection between the computers, on the IP, then the message will get through...