Efficiently process incoming packets using bpf (which runs in the kernel)
Respond to all NDP solicitations on an interface
Respond to NDP solicitations for whitelisted addresses on an interface
Proxy NDP between interfaces with an optional whitelist
Optionally determine whitelist automatically based on the IPs assigned to the interfaces
Permissions required: root or CAP_NET_RAW
Easily expandable with modules

Installing & Updating

Download the latest release from the releases page and move the binary to the /usr/local/bin/ directory under the filename pndpd.
Allow executing the file by running chmod +x /usr/local/bin/pndpd
For systemd users: Install the service unit file

wget https://raw.githubusercontent.com/Kioubit/pndpd/master/pndpd.service -P /etc/systemd/system/
systemctl enable pndpd.service

Download and install the config file

mkdir -p /etc/pndpd
wget https://raw.githubusercontent.com/Kioubit/pndpd/master/pndpd.conf -P /etc/pndpd/

Edit the config at /etc/pndpd/pndpd.conf and then start the service using service pndpd start

Manual Usage

pndpd config <path to file>
pndpd responder <interface> <optional whitelist of CIDRs separated by a semicolon>
pndpd proxy <interface1> <interface2> <optional whitelist of CIDRs separated by a semicolon applied to interface2>

More options and additional documentation in the example config file (pndpd.conf ).

Developing

Building

For building, the version of go needs to be installed that is specified in the go.mod file. A makefile is available. Optionally adjust the modules variable to include/exclude modules from the modules directory.

make build
make release

Adding Modules

It is easy to add functionality to PNDPD. For additions outside the core functionality you only need to keep the following methods in mind:

package main
import "pndpd/pndp"

pndp.ParseFilter(f string) []*net.IPNet

responderInstance := pndp.NewResponder(iface string, filter []*net.IPNet, autosenseInterface string)
responderInstance.Start()
responderInstance.Stop()

proxyInstance := pndp.NewProxy(iface1 string, iface2 string, filter []*net.IPNet, autosenseInterface string)
proxyInstance.Start()
proxyInstance.Stop()

New functionality should be implemented as a module. You will find an example module under modules/example/.

Pull requests are welcome for any functionality you add.