libnetaid

libnetaid is a shared C library based on the RTnetlink service routines of the linux kernel. It provides useful utilities focused to the development of both CLI and GUI user interfaces to render networking management with minimal dependencies and following the KISS principle, together with other tools like wpasupplicant, ifupdown and libiw.

Installation via APT

Use the APT package manager to install libnetaid.

apt-get install libnetaid libnetaid-dev

After that, development headers will be located in:

/usr/include/i386-linux-gnu/simple-netaid    (for 32 bits) 
/usr/include/x86_64-linux-gnu/simple-netaid  (for 64 bits)

Building your own packages

You can build your own debian packages in a very easy way using git-buildpackage (a wrapper for dpkg-buildpackage). All you need to do is:

$ git clone https://git.devuan.org/aitor_czr/libnetaid.git
$ cd libnetaid

If you type git status you can see all:

On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working directory clean

To list all the local and remote branches type:

$ git branch -a

Let’s checkout on the following branches (in this order):

$ git checkout -b pristine-tar origin/pristine-tar
$ git checkout -b gbp-release_0.1 origin/gbp-release_0.1

The prefix gbp reflects those branches containing the debian folder. Now we can build the packages:

$ gbp buildpackage

Once the packages have been generated, go to the build directory and install them:

$ cd ../build-area
$ sudo dpkg -i *.deb

Building from source

Note: This paragraph needs to be updated, since cmake has been replaced with autotools in the master branch.

If you are using a different package management system, then you’ll need to build the project from source.

Build dependencies

The current version of libnetaid has been tested under Devuan Beowulf, requering:

• gcc (4:8.3.0-1)
• cmake (3.13.4-1)
• libiw-dev (30~pre9-13)

Procedure

Download the tarball from the git repository of devuan libnetaid, extract it with tar xvf master.tar.gz and go into the extracted folder. There, run the following commands:

$ mkdir build
$ cd build
$ cmake ..
$ make
$ sudo make install

Note: By default, CMake does not provide the “make uninstall” target; so, in general, you cannot do this. However, libnetaid adds an uninstall target to the CMAKE generated Makefile, in such a way that you can run:

$ sudo make uninstall

You can test libnetaid trying to build one of the examples bellow or the snetaid daemon. If the library in /usr/local/lib is not found (this is the destination when building from source), what you need to do is to tell the runtime loader to also look in this directory for libraries. There are two ways for that:

• The first way is to add the path to the LD_LIBRARY_PATH environment variable:

      export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/lib"

• The second way is to update the configuration file of the runtime linker. This can happen either in the /etc/ld.so.conf file, by putting the line /usr/local/lib somewhere in that file, or by creating a new *.conf file in the /etc/ld.so.conf.d/ directory that contains the new path. For example /etc/ld.so.conf.d/99local.conf with just /usr/local/lib in it. This is the recommended way of doing this, as it allows you to keep your custom library paths separate from paths set by the system. The “99” prefix is there to make sure the file is loaded last compared to other files there, so that it won’t preempt system paths that could contain the same libraries (read here). After you modify/create the file in /etc, you need to update the /etc/ld.so.cache file:

      $ sudo ldconfig

Additional dependencies

To get all the features of libnetaid working you’ll need to install some additional packages, they are:

• wpasupplicant
• ifupdown

A typical configuration of /etc/network/interfaces might be:

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

allow-hotplug eth0
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet dhcp

Replace here the names of the network devices according to your system.

You need to restart the service for the changes to take effect:

sudo service networking restart

Usage

libnetaid uses sbuf structs to handle char arrays, whose life cycle is (have a look at the sbuf.c file):

struct sbuf s;
sbuf_init(&s);
sbuf_addch(&s, 'F');     /* adds a character */
sbuf_addstr(&s, "oo");   /* adds an array */
free(s.buf);

The following example consists of a very simple C program showing the names of the network interfaces:

/ * *
  *
  *  main.c
  *
  */

#include <simple-netaid/sbuf.h>
#include <simple-netaid/interfaces.h>

int main(int argc, char **argv)
{
	struct sbuf wired_device, wireless_device;
	sbuf_init(&wired_device);
	sbuf_init(&wireless_device);	
	get_interfaces(&wired_device, &wireless_device);	
	printf("Wired device: %s\n", wired_device.buf);
	printf("Wireless device: %s\n", wireless_device.buf);	
	free(wired_device.buf);
	free(wireless_device.buf);
	return 0;
}

You can build it as follows:

gcc main.c -o main -lnetaid

Output example:

Wired device: eth0
Wireless device: wlan0

Another example using netproc might be:

/ * *
  *
  *  main.c
  *
  */
 
#include <simple-netaid/sbuf.h>
#include <simple-netaid/netproc.h>

int main( int argc, char **argv)
{
	struct sbuf s;
	sbuf_init(&s);
	netproc(&s);
	printf("%s\n", s.buf);
	free(s.buf);
	return 0;
}

Output example:

Connected to wlan0
MAC Address=2C:D0:5A:E8:9E:9F
IP Address=192.168.0.12
BROADCAST=192.168.0.255
NETMASK=255.255.255.0
PROTOCOL=IEEE 802.11
ESSID=Euskaltel-58YA
QUALITY=94%

Functions

Here you are a list of other available functionalities:

// Brings up the interface (analogous to "ip link set <interface> up")
void interface_up (const char* interface); 

// Brings down the interface (analogous to "ip link set <interface> down")
void interface_down (const char* interface);

// Returns the current status of the interface ( 1 | 0 ) -> ( UP | DOWN )
int get_interface_status (const char* interface);

// Brings up the interface (analogous to "ifup <interface>")
void ifup (const char* interface);

// Brings down the interface (analogous to "ifdown <interface>")
void ifdown (const char* interface);

// Shows all the available active wifis (as root)
void print_active_wifis(const char* wireless_device);

// Wireless connection attempt via wpa_supplicant
void wireless_connection(const char *ifname, const char *essid, const char *password);

// Wired connection attempt
void wired_connection(const char* wired_device);

// Disconnects the network device
void disconnect(const char* device);

// Returns the name of the connected network device, null if you are disconnected.
char* iproute();

// Asigns to the buffer detailed information concerning to the network connection.
void netproc (struct sbuf* buffer);

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

libnetaid is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

libnetaid is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

See the COPYING file.