I need to listen to a TCP port and collect the binary data from the port in my iphone how this could be done . I had searched a lot for the same but did not find anything worth, please help me any links, or sample code be greatly appretiated
The only thing you need to do is open a socket, you have two options:
Create the socket in pure C:
Sockets in C
Or use the classes that Apple provides to work with sockets:
Introduction to Stream Programming Guide for Cocoa
If you are going to do something simple, the first option is the easiest
There is a very useful socket library called GCDAsyncSocket on github that can be used to make both TCP/UDP sockets and comes with delegate methods for reading and writing data
GCDAsyncSocket
Related
I have tried using GCDAsyncUdpPacket.m and .h files for creating a udp communication channel. But through that i could send only one line messages. I need to send an entire file for example an Image.
Any help would be much appreciated as I am totally new to this platform.
Since UDP is not an error checked protocol, just cramming the binary data down a UDP socket will not be reliable, as some of the packets will likely be dropped, or arrive out of order at the far end.
If you want to ensure error-checked, in-order, and reliable data, open a TCP socket and send it that way.
In IOS, you can use the NSStream class to do this, though you'll have to look at a lot of sample code to understand the various ways it can be used in an iPhone app. To implement it well, you need to understand how run-loops work (NSRunLoop) and how delegation works in Cocoa.
For me, I tend to avoid all this and start network tasks on a separate NSThread, opening a TCP socket using unix's socket(), connect() and send() primitives. Once you get these working, they can be cut and pasted into other code (or put into a personal code library) so you don't have to remember how to do it. :-)
There is a lot of sample code out there for the BSD primitives socket(), accept(), bind(), connect(), send(), and recv().
I'm just reading about TCP and UDP and from what I've read when the packet gets encapsulated in the IP protocol and the header gets added is it not possible to create a false IP address at this stage?
Granted, the response will never be received on your connection, but is this possible?
I do not want to do this btw. I'm in no way associated with immoral ethics. It's just something that I had to ask whilst reading about TCP and UDP. I'm actually learning how to use sockets in C++ for a game I'm working on.
Yes, this is possible.
Use raw sockets and craft your own packets
Use scapy, hping, etc
Search for "packet crafting"
EDIT
A nice scapy tutorial that teaches you to send lots of valid and invalid stuff is here.
In a nutshell, I am trying to write a C++ XPCOM component which listens on a UDP port and calls a callback function (a javascript function) every time a UDP packet arrives.
Sorry if the answer is too obvious but I was wondering what are the ways to listen on a UDP port with Mozilla (Preferably something easy to do)?
I know that there is an interface called nsIServerSocket which allows some listeners to be attached to it, but this is only for opening TCP ports. Is there any UDP equivalent of this (where I can attach a listener which is notified every time a UDP packet arrives)?
I also know that I could probably use PR_OpenUDPSocket and such. Is there a way of using this without dealing with threads? (As far as I understand I have to return to the calling javascript function after opening the port).
Thanks.
Why do you need to restrict yourself to Mozilla's API if you are writing C++ code? You can use the POSIX socket API directly, see How to set up a Winsock UDP socket? for a WinSock example (the only difference for Linux and OS X should be that WSAStartup() call is unnecessary). nsIServerSocket is mainly useful for JavaScript code that doesn't have the option to use the system libraries directly.
If you prefer a straight answer to your question: no, there is no XPCOM API to create UDP sockets. You already found the NSPR API (PR_OpenUDPSocket()) but it is probably designed with DNS communication in mind since that's pretty much the only UDP communication a browser would do. Don't expect much here.
And a side-note: you might want to avoid binary XPCOM components and create a native library that can be called via js-ctypes instead. See here for the details.
I am trying to make an application for iPhone that can listen for traffick on a specific network port.
A server on my network is sending out messages (different status messages for devices the server handles) on a specific port.
My problem is that when I make a thread and makePairWithSocket I block the port for others who want to send messages to the server, so I only want to listen to the traffic on a specifyed port and then check for specific heraders and then use those messages.
I know how to make the connection and talk to the server using write and read streams, but then I makePairWithSocket and block the port for all other devices on the network
Any one that has any suggestions on how to listen on a port in Objective-C without pairing with the server?
Thanks in advance
Daniel
Check out CocoaAsyncSocket. It gives you a nice and structured way (with delegates) to send and receive data... also with multiple clients. The documentation is quite good. project link
edit: Have a look at the AsyncUdpSocket class for a stateless UDP connection.
I think this requires network support well below the socket API level, perhaps at the hardware driver level, assuming the packets are even being routed to your device.
I have a TCP server running on a machine. (implemented in Java). I need to connect to that server from a iPhone and send data to the server and also, receive data on the iphone when server pushes me data. So I need to be notified when data pushes from the server.
Is there a way to do this in Objective C(socket programming). Although I googled I couldn't find a solution. But I saw CFSocket etc.
Please anyone have a solution?
after a possible solutions in the internet, I found a nice asynchronous TCP and UDP socket Library here. (http://code.google.com/p/cocoaasyncsocket). This library worked really well for me so far. This wraps the CFSocket and CFStream.
Thanks for your replies.
You can use the CFNetwork family of classes to implement lower level sockets. Apple has an introduction document that describes the use of these classes.
CFSocket calls and similar will let you create sockets. You can then use CFStreamCreatePairWithSocket() to create a CFReadStreamRef and CFWriteStreamRef, which you can cast to NSInputStream* and NSOutputStream*.