# nflog-bindings-rust
[](https://travis-ci.org/chifflier/nflog-rs)
## Overview
nflog-rust is a wrapper library for
[libnetfilter-log](http://www.netfilter.org/projects/libnetfilter_log/). The goal is to provide a library to gain access to packets queued by the kernel packet filter.
It is important to note that these bindings will not follow blindly libnetfilter_log API. For ex., some higher-level wrappers will be provided for the open/bind/create mechanism (using one function call instead of three).
Since libraries to decode ip packets are already available, the bindings
will use them.
To use the library, a program must
- open a queue
- bind to a network family (`AF_PACKET` for IPv4)
- provide a callback function, which will be automatically called when a packet is received.
- create the queue, providing the queue number (which must match the `--nflog-group` from the iptables rules, see below
- run a loop, waiting for events. The program should also provide a clean way to exit the loop (for ex on `SIGINT`)
## Documentation
Documentation is created using the `cargo doc` command.
## Example
See [test_nflog](src/bin/nfprint.rs) for a minimal example.
## IPtables
You must add rules in netfilter to send packets to the userspace queue.
The number of the queue (--nflog-group option in netfilter) must match the
number provided to create_queue().
Example of iptables rules:
iptables -A OUTPUT --destination 1.2.3.4 -j NFLOG --nflog-group 0
Of course, you should be more restrictive, depending on your needs.
## Privileges
nflog-rust does not require root privileges, but needs to open a netlink socket and send/receive packets to the kernel.
You have several options:
- Use the CAP_NET_ADMIN capability in order to allow your application to receive from and to send packets to kernel-space:
```setcap 'cap_net_admin=+ep' /path/to/program```
- Run your program as `root` and drop privileges
## License
This library is licensed under the GNU General Public License version 2.0, or (at your option) any later version.