This project is a part of Projektova Prax subject, currently being taken at Brno University of Technology.
The aim of the project is to create profiles of computer networks with emphasis on communicating processes, running on certain hosts. The goal is reached by introducing a new system, based on Cisco NetFlow, which collects data about processes separetely and use them to extend NetFlow dumps.
The project is divided into two parts: ProcessTracker and FlowUpdater.
This daemon provides collecting data about processes at certain host. ProcessTracker is using scripts hosts.sh and binds.sh to scan available network interfaces and to get the names of processes, listening at certain ports, respectively.
To store and compare process bindings, a search tree (implemented in hashtbl.c) is used while storing data with key (IPadd, port, proto) and data (the process name). In addition, a FIFO queue is used to handle differences in the search tree as events which happen in time. Queue is implemented in queue.c
The main program of ProcessTracker is an infinite loop, providing status updates periodically. In an status update, the result of script bindings.sh is compared with data stored in the search tree. If any difference is detected in process bindings, a new event is emmited to the queue.
The rest of status check is reserved for serving clients the data stored in the queue.
Implementation can be found in daemon.c
FlowUpdater works with outputs of NetFlow collector using 3rd party library libnf. Before updating flow records, process data is received by ProcessTracker using UDP and data are used to reconstruct the search tree at FlowUpdater side.
For each NetFlow record in NetFlow dump file, the search tree is accessed with key composed of source IP, source port and protocol. If entry with specified key exists, entry's process name is inserted into flow record. Otherwise, a text literal (place holder) is used. Implementation can be found in nfaltern.c
The implementation is based on specialized modules created for transparency purposes.
Data structures used to store data are described in structure.h
netstat.h together with host.h provide tools for accessing system network configuration.
udp.h defines comfort simple wrapping layer to use UDP server-client model.
Note: libnf.a included in main directory was compiled under Linux.
In order to compile under FreeBSD, compile libnf first and copy .a from
/src/.libs/libnf.a to compilation directory.
Project has been tested at Ubuntu 16.10 with standard gcc.
make
The previous command produces binary files deamon and nfaltern.
Deamon expects port number to be set in arguments.
./deamon PORTNUM
Note: to have an access to all processess, deamon must be run with root rights.
To update files, place nfaltern into directory where nfdump dumps its data.
./nfaltern IP PORTNUM TIME
where IP and PORTNUM stand for IPv4 address and port of deamon and TIME is the delta time between two flow updates, multiplied with 10, in seconds.
An example of extended flows can be found in directory profiles. For seeing process collumn in flows, it's neccessary to run nfdump with special command-line argument, specifying output format. %uname specifies the process name added into NetFlow flow dumps.
To see an extended output, use this command
nfdump -o "fmt: %line %uname" -r <directory-to-extended-dumps>
In order to get IPv6 flows from softflowd, -v 9 must be specified explicitely.
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