Using either XNA OR just the usual c# win forms application, which would be the best way to create the feature that enables text messages to be sent from me to my friend over the internet?
I don't know if this matters or not, but I now have 3 Mobile Broadband internet... so it's like... Wireless internet, does that matter?
It is quite difficult to "reach your friend over the internet", whatever the framework.
Reaching someone's PC requires knowing the IP address of the destination PC. If the PC is behind a router, the PC most likely has a private IP address, thus is unreachable unless the router implements some form of forwarding (in which case a given TCP port is forwarded to a given PC's internal IP address). Then, you need to configure the router to use DDNS so that your code can get at the router's IP address.
So, it is possible (using the classes mentioned by #Bob), but not for the faint of heart.
The way professional programs (like chat clients) do it is to have a central server that relays messages. The code running on your PC and on your friend's PC sends messages to this server instead of directly to each other, so one doesn't need to know the IP address of the other one. But going this route requires some form of hosting for the server PC.
You could look into the Socket class or the simpler TcpClient and TcpListener. Whether XNA or Winforms shouldn't matter. Using XNA on the Windows platform gives you access to the entirety of the .NET framework, including the networking aspects.
I agree with Timores, you can't directly reach the device of your friend and you will need a server for that. Sockets are not something operators allow when you are connected using 3G and not WIFI.
You are welcome to try if you like the Skiller SDK solution: www.skiller-games.com (full disclosure: I am from Skiller), we have distributed servers so you don't need to host anything and besides other tools you can use the built in social layer where your users will be able to make a list of friends and send messages to each other.
Hope that helps.
Related
I would ask if it is possible to get information about connected devices in the local wireless network.
Is there any api for xamarin to do that?
It doesn't seem like Xamarin has an API for this, but Microsoft introduced a Ping (documentation here) and a NetworkInterface class (documentation here) in .NET 2.0 that you could use.
Essentially, what you need to do, is to ping the IP adresses on your local network, which you can do asynchronously using SendAsync(). You then register the callbacks by registering an EventHandler to PingCompleted. The callback will contain a PingCompletedEventArgs which you can use to retrieve basic information (e.g. IP, MAC and Hostname) about the device.
You can find a complete guide of the implementation here.
I hope this helps.
Note: Of course, it all depends on what type of information you expect to retrieve. Although, I think you can only expect to retrieve the basic information about devices on your network, as everything else could potentially be a security risk.
Secondary note: Depending on which devices you wish to discover on your network, you could also use the SNMP component which will allow you to discover devices such as routers, switches, printers, and so on.
I am thinking you are looking for which devices at layer-2 have registered with your wireless controller/accept-point/router and by being connected you are referring to how many have successfully establish 802.x handshake (implying security exchange and channel establishment has occurred).
There exists a tool to do this work (never tested this on my mac) and you can check Flying Squirrel for the above purpose. This will ofcourse be an independent sniffer over the wireless network and you'll require the password used for wifi etc. for making this work.
If you have access to a device that exposes instrumentation (MIB) then you can get that information from the device by SNMP walking the device. At this level you'll of course get the MAC address table and if DHCP is running on your router then perhaps access to DHCP table can give you information about the MAC to IP mapping. On some medium to high end networking gear MIBs like CISCO-DOT11-ASSOCIATION-MIB can be used. Also I am assuming you are refering to 802.11 here there are other wireless protocols like BlueTooth etc. in play as well which use different scanning techniques so the answer depends on what kind of network you are referring to here.
Ok, I figured out a way without snifing the local network. It makes more sense the following way in my case...
Case:
I want to connect to an device which provide an own wlan network. Then I connect to it and pass the home wlan network to it. The device restarts and is now configured as a client in the local home network. And now I need the local ip for service communications.
My Solution:
I do a register call to the device. The device gives me the mac address. Now I register (with phone device) the mac address from the access point device in a online service. After the device has been restarted and get the new local ip address it sends to the online service.
And the I can retrieve the local ip address through polling or through getting push notification from the server...
I need to get two machines to communicate via WiFi without using IP (I do not want to use IP sockets). The solution preferably should work with both WiFi modes (infrastructure such as regular WiFi and ad-hoc such as WiFi Direct). A C# sample code would be great please.
I have searched a lot and could not find any code similar to a socket program that sends and receives data between two machines (p2p) but using only WiFi without any IP.
Apple's Multi-Peer Connectivity framework supports setting up a Peer to Peer connection without the developer having to manage the IP connectivity directly, but it uses IP to deliver data and is limited to Apple devices.
It's possible to do this if you are willing to write the low-level c code to do it, but any solution which avoids IP will have to recreate significant portions of the protocol to be useful and would almost certainly require much more work than just using the IP features of the OS.
For very simple forms of communication between Wi-Fi stations you can use custom Action Frames and Information Elements, but those require very low-level access to the driver.
I've looked around at various C# Packet Sniffing tutorials and have built one that can parse packets sent to and from my computer. This is awesome, but I haven't found anything that relates to intercepting packets from another computer (obviously on the same network), e.g. from a different computer to a router.
Am I correct in thinking that any packets sent by a computer are visible to, not only the router, but any other computers on the same network? If this is the case, does that not mean that intercepting these packets is something we can do in C#?
To those who are desperately copying and pasting links to Wireshark etc. I appreciate your time but this is more of a learning experience for me, so I'd like answers relevant to C# if possible!
In summary, how can I intercept packets in C# that don't concern my computer? E.g. From my laptop to my router?
Assuming you're in an ethernet switched network rather than something funky like a token ring: Even the great Wireshark is limited in what it is able to see because it runs in the same confines as what you're trying to build - its host PC.
Unfortunately, your PC can only see the packets that hit its network interface. This means that in a layer 3 routed network you're unlikely to see any packets that aren't intended for you, unless of course your PC is the router.
You'll need to look into SOCKS5 proxies and the like to achieve the level of network transparency your question infers. While implying a small bit of network and configuration overhead, a proxy will provide you the most visibility into the traffic you're after.
M.Babcock already mentioned in his answer that your computer in a switched network won't see the traffic between two other computer.
Some (managed) switches and routers have the feature to send all traffic to a monitoring port. On this port you can connect your computer and use wireshark/pcap etc. to see the all the traffic that is passing through the switch/router.
Or, if you still have one reachable, put a Hub between Laptop and router and connect your pc to the hub. The Hub will forward all traffic to the other ports, as he doesn't care about the mac addresses.
So this is really not depending on any programming language but only on network management.
Im sorry if this been asked before, but couldnt find anything about this particular matter.
I try to find out with which of my own ip's my computer use to connect to a remote ip.
I use some kind of socket setup both ways etc, and im sending my ip (and other stuff with xml) to another server so it knows how to contact me.
But how do i figure out which ip i should send to it?
I have the servers ip or host name, but trying with
Dns.GetHostEntry("host").AddressList
But that only gives me the ip of the remote host and not how my computer reach it.
Is my question solveable at all or is this just wishful thinking?
Can you have the remote host capture that data? That end would surely have it.
If you're using UDP then this is exactly what the STUN protocol was designed for. STUN is used in VOIP applications (among other P2P systems) to be able to tell what a specific connection looks like on the internet.
One very reliable .NET implementation that implements STUN is included in the Lumisoft.NET library (source code available here). I've used it myself for to satisfy this specific task for applications ranging from VOIP to P2P VPN alternatives. It is very easy to use and is standards compliant.
NOTE: I am NOT in any way affiliated with Lumisoft, I've merely used their library in several different applications
Ok, quick update that wont help anyone except myself.
But.
Found out that i can send hostname instead of actual ip, will work for now and most cases, and let the DNS do what its suppose to do :)
I have a device connected to a host computer through cradle usb. Now, I'm just wondering if I could use C# sockets to communicate with the device (ie device sending data, host computer processing it then replying back to the device). How can I accomplish this? by that, what ip address etc etc.. do I have to change so that it would connect cause I have the sockets working on wireless. If not, then is there a way to connect to the device, open and read a file (a text document to be more specific) from the device to my host application.. any ideas?
Thanks! :)
Depending on your target device, when you connect via ActiveSync it likely makes a local RNDIS network connection between teh two devices. You can resolve "ppp_peer" as the partner's network name instead of trying to use a hard-coded IP address (IIRC the IP is different on XP than on Vista).
Be aware that it's not a full connection. TCP packets gets passed through, but things like ICMP do not.
Of course, this just gives you a socket connection, just like if you were to connect between two PCs. It's not going to allow you to do file system operations unless you have an app on the other side listening for commands. If you want that type of thing, Microsoft provides the Remote API (RAPI) interface (wrapped in managed code here)for a lot of basic commands, and it can be extended (with C) to do anything you'd like.