I need to connect via TCP to a port that's behind a firewall, accessible through an SSH tunnel. I can achieve connection by opening a tunnel and hittting that port, but I want to build this tunneling in to my application.
Additionally, I want to be able to provide automatic login by use of having authorized keys on the server
This must work on the following platforms (in order of importance)
iOS (trickiest because I can't fork an ssh tunnel like I can on other platforms)
OS X
Linux
Windows
What's the easy way to do this? I don't want to spend a great deal of effort obviously since this isn't the meat of my application. But I'll reuse it so I may care enough to "do things right"
But libssh2 is BSD-licensed and appears to have the functionality needed
Looks like: libssh2_channel_direct_tcpip_ex will be the call
Note that the LGPL'd libssh is a problem because on iOS apps you MUST statically link and CANNOT dynamically link to libraries. Therefore, using an LGPL'd library means my source becomes open source.
Libssh is a very good client implementation for SSH protocol. I have written a blog on this. There is also a sample application demonstrating the same. We use the same technique in MONyog (MySQL monitor).
There is a commercial LIB if you want to have a look at, www.chilkatsoft.com/, it is a genric C++ lib for all languages, in it there is a support for SSH tunneling for IOS.
Does the LGPL differentiate between linking dynamically and statically? I don't think so.
The library code (i.e. embedding your own SSH implementation) looks most versatile to me. Except the fact that you might inherit security problems.
On MacOSX/Linux/Unix, you can simply invoke 'ssh' and assume it exists (or make it as a precondition). On Windows, you would rely on putty and friends. I don't think that's a good idea.
Related
I'm interested in studying the 9P FS, currently been reading the source available from these implementations: http://9p.cat-v.org/implementations
Is 9P obsolete? Are you using it for some application?
(also I've found this, some perfomance test between 9P and NFS: http://graverobbers.blogspot.com/2007/08/v9fs-performance-versus-nfs.html)
No, 9P isn't obsolete; I don't know of a protocol that does what it does and is clean and well defined enough to be implemented correctly in almost any language that exists.
9P is used in a variety of systems. A couple of recent uses in arm-js (an ARM emulator) and 9webdraw (a GSoC project that implements the Plan 9 /dev/draw). Both are HTML5 Javascript implementations.
Just to add a bit, both the Linux client implementation and several servers are under active development, so I'd say that's a pretty clear sign that folks still have use for it. One of the areas its seen heavy use more recently is the virtio-9P (aka virtfs) which is part of qemu/kvm and can be used for direct guest to host file access. It's also been used in several experimental operating systems projects (Libra, PROSE, FusedOS) and incorporated into other operating systems (BSD, MacOSX, Windows, Linux) and hypervisors (in addition to the KVM instance above, its also been incorporated in various ways into Xen). 9P is actually being used in supercomputing deployments (both for Plan 9 and Linux, see the diod project on Sourceforge).
I think the reason is that the protocol is quite simple, so implementations also tend to be quite simple and easy to integrate elsewhere (there are several applications both inside and outside the Plan 9 world which use 9P as an interface to the application, in much the same way that some web developers use RESTful interfaces).
The protocol has a couple of different variations including the 9P.L variant which was developed specifically to match the Linux VFS API better. It adds a bit of complexity to the protocol in the addition of operations, but removes some of the complexity of mapping Linux VFS API -> 9P and vice versa.
It is used in Erlang-on-Xen both as a storage protocol for goofs http://erlangonxen.org/blog/goofs-simple-filesystem
It is the way erlang on xen instances in other ways too, see here:
http://erlangonxen.org/more/9p2000e
Also, it's used by libvirt stuff with QEMU.
http://wiki.qemu.org/Documentation/9psetup
9p, to me, is like the Scheme of network protocols. For the most part, it is very simple, but people see need to extend it to fit their environments. Luckily this is done in ways that are often backwards compatible.
In addition to everything mentioned in the other answers, Microsoft is using 9P as part of their Windows Subsystem for Linux.
They add a 9P server to each Linux distribution that is running as a guest, so that Windows can mount the Linux filesystem over 9P, and Windows processes can transparently access the files on Linux's ext4 partition.
Is there any C/C++ lib(of course Open-sourced) for developing applications of stateful inspection on network session, for instance, following the FTP session state?
I know there is a pre-processor module in Snort namely stream4. But an independent lib is more flexible for us which implemented in C is preferred.
Thanks.
I'm not sure how applicable this will be to whatever you're doing, but you could try to extract the Linux NAT connection tracking code and adapting it to your needs. It's not a nice pre-made library, but it's a start.
I need to create a web-controlled application (that lives in the browser) that can connect to and read data from devices connected via USB or the serial port.
At the moment, I'm using an ActiveX control to do this. However, I'm like to re-write this system to make it cross-browser (support Firefox) and eventually cross-platform (support Safari on Mac). ActiveX is neither cross-browser or cross-platform, so I'm looking for an alternative technology.
My first inclination would have been to use Silverlight, because Silverlight 4 grants access to COM Automation. Unfortunately, this only works with OOB (Out of browser) Silverlight applications - in-browser systems are still bound in a sandbox and do not have access.
So, what technologies exist (frameworks, browser plug-ins, etc) that will allow me to interface with a USB/Serial device from within a browser-based web application? What are the pros/cons of each?
I think your best bet is probably Java in this case. USB, though an industry standard in terms of protocol is definitely not standardised in terms of bare-metal implementation. For this reason, you will still need a different Java USB implementation for each distinct platform (windows, linux, osx, bsd) that you intend to support. Of course you will also have to pay for code-signing certificates so you can try to convince people to grant your application the kind of access it requires; something that browsers try very hard to deny access to and most people in this day and age are very unwilling to grant. That said, there's an old IBM article here on the various Java USB projects that makes a good read. Good luck.
http://www.ibm.com/developerworks/library/j-usb.html
-Oisin
It might be painful, but you could use a signed Java applet. Signed Java applets can have full access to the user's system.
Java does not have built in USB support, so you would probably need to roll your own JNI interface to native USB APIs.
Using JNI in an applet can be tricky. I've done it before. If you Google the topic, most results say "don't do it" or "you can't do it." Well, you can do it.
This is how I did: I packaged the native libraries (DLL, so, etc) inside the applet's JAR, and then read the native libraries out of the JAR using e.g. getResourceAsStream. I then wrote the libraries out to an appropriate location on disk (e.g. ${user.home}/.myapp/.) I then used System.load to load the JNI DLL.
There can be some ClassLoader issues with JNI libraries and applets. The issues are subtle and difficult to explain. They basically have to do with the fact that a JVM can only load and bind a given JNI library once per VM instance, but applets get instantiated a lot, often with their own new ClassLoader, which can be problematic. The work that Sun did on process separation in the Next Generation Browser Plugin may have relieved some of these issues, but your users will only have this if they are using Java 1.6.0_10 or later.
It is also possible to use JNA within a signed applet. I would not recommend using JNA to access USB APIs directly. But JNA can sometimes be a big time saver for accessing simple native functions. Although once you've set up your JNI infrastructure, JNA probably has less value.
Here are a few other random thoughts:
Java WebStart - Can be launched from browser, but runs outside the browser
Microsoft ClickOnce - Can be launched from browser, but runs outside the browser
Flash / AIR - Can't escape its sandbox
The best solution I've come across thus far is the cross-browser/cross-platform plug-in system called FireBreath. This is a framework built in C++ that allows you to generate plug-ins for both ActiveX and NPAPI from the same codebase.
So build it once, make it work, and it compiles to one DLL that you can deploy in either environment: ActiveX for IE, NPAPI for everyone else.
I'm working on a project that's supposed to work on both Windows and Linux (with an unofficial Mac port as well) that emulates a true colour system console.
My problem is that recently there appeared a request for textfield support (yes, console-based) and it would be cool to add the possibility of copying text to clipboard and pasting from it. Is there a way of achieving this that will:
be done in C (not C++),
work in both Windows and in Linux (preprocessor macros are an option if there's no platform-independent code),
require no extra libraries to link to?
Thanks in advance for your help.
If you're not using a cross platform UI library (like wx or something), then it sounds like you're just going to have to write native clipboard code for each platform you want to support.
Remember, on Macintoshes, you copy with Command-C, not Ctrl+C :)
The clipboard is inherently an operating system defined concept. The C language itself has no knowledge of what a clipboard is or how to operate on it. You must either interface directly with the OS, or use a portability library that does this on your behalf. There is no way around this.
Personally I would define my your own function
getClipboardText();
That is defined in two different header files (linux_clipboard.h, windows_clipboard.h, etc) and then do pre-proccessor stuff to load the appropriate one accordingly. I don't really code in C/C++ so I'm sorry if that didn't make any sense or is bad practice but that's how I'd go about doing this.
#if WIN32
#include windows_clipboard.h
#endif
That sort of thing
Remember:
For linux you have to deal with different window managers (Gnome, KDE) all with different ways of managing the clipboard. Keep this in mind when designing your app.
You may be able to communicate to the clipboard by using xclip. You can use this python script here to do this job via communicating with 'dcop' and 'klipper' here. That is for KDE, I do not know how it would be done under GNOME... You may also be able to do this independantly of either GNOME/KDE by using DBUS, although I cannot say 100% confidently on that either...
Just be aware, that for a truly cross-platform job, you have to take into account of the different GUI's such as under Linux, X is the main window manager interface and either GNOME/KDE sits on top of it..I am not singling out other GUI's such as FluxBox, WindowMaker to name but a few, and that there will be a lot of platform dependant code, and also in conjunction, you will be dealing with Windows clipboard as well..all in all, a big integrated code...
Have you not considered looking at the raw X programming API for clipboard support? Maybe that might be better as I would imagine, GNOME/KDE etc are using the X's API to do the clipboard work...if that is confirmed, then the work would be cut out and be independant of the major GUI interfaces...(I hope that would be the case as it would make life easier for your project!)
Perhaps using compile-time switches, for each platform...WIN, KDE, GNOME, MAC or use the one that is already pre-defined..
Hope this helps,
Best regards,
Tom.
I'm lookin for a portable wiimote library. I want to use the wiimote for the hardware it has (but I don't need to access any data stored on it).
Required features:
access to all the buttons (as an exception, no use of the power button is OK)
make the wiimote play sound
talk to nunchuks and classic controllers
preferably: make the wiimote rumble.
interface with C. Preferably native C. Bonus points for bindings with Haskell or python.
The library should port to Linux, Windows and OS X (in order of importance) and should be agnostic with respect to CPU architecture.
Anyone got a good suggestion?
Haven't use it (I've only read about the managed Wiimote library really), but you may want to check out wiiuse. It seems like the most complete of the native libararies.
Others include:
GlovePIE
WiiYourself
You can use my WiiMouse program to do this (which is based on the wiimotelib open source project), it allows you to connect via named pipes and play PCM sounds and use all the attachments including the MotionPlus, it even calculates the MotionPLus vectors for you, you can get it here:
http://home.exetel.com.au/amurgshere/wiimouse.phtml
See the download for an example on how to connect to a wiimote via named pipes and play sounds and stuff.