Neighbor Discovery Proxy

This project is an implementaion of RFC 4861 section 7.2.8 written in Rust.

It is similar to another project called ndppd, but it provides an extra recipe called "rewrite", which may help people build IPv6-compatible overlay networks.

Any ideas and issues are welcome.

usage

Proxying Neighbor Discovery packets among interfaces.

Usage: ndproxy [OPTIONS]

Options:
  -c, --config <CONFIG>  path to config file [default: /etc/ndproxy.toml]
  -h, --help             Print help
  -V, --version          Print version

You can find an example of configuration file here.

extra recipe: rewrite the prefix

Let's say your network has multiple upstreams and relies on Network Prefix Translation (RFC 6296) (or NETMAP).

For instance:

        2001:db8:1::/64                  2001:db8:ffff::/64
              ↑                                  ↑        ↑
        ISP1, translated via NETMAP        ISP2, NPTv6   Other Users
              |-------- fec1:2:3:4::/64 ---------|
                              ↑
                      your local devices

To make your local devices available to both of your upstreams while not disturbing other users, you may want a config like:

[ndp]

[ndp.ISP1]
type = "forward"
proxied_prefix = "2001:db8:1::/64"
rewrite_method = "netmap"
local_prefix = "fec1:2:3:4::/64"
<redacted>

[ndp.ISP2]
type = "forward"
proxied_prefix = "2001:db8:ffff::/64"
rewrite_method = "npt"
local_prefix= "fec1:2:3:4::/64"
<redacted>

While running, ndproxy will monitor Neighobor Solicitations from both of your upstreams.

When it captures a valid NS, it will translate the Target Address of the NS to your own private address, and perform Neighbor Discovery locally.

If the requested neighbor exists, ndproxy will send a proxied Neighbor Advertisement back to the related interface.

performance

Just a random result, but I am happy getting it :)

As of v0.4.0, ndproxy seems to be faster than ndppd.

I have ran ndproxy and ndppd on a poor-performance machine with similar configuration:

# cat ndproxy.toml
[ndp]
[ndp.conf1]
type = "forward"
proxied_prefix = <redacted>
proxied_ifaces = [ "wan0" ]
forwarded_ifaces = "lan0"
rewrite_method = "netmap"
local_prefix = <redacted2>

# cat ndppd.conf
route-ttl 30000
proxy wan0 {
    router yes
    timeout 500
    ttl 30000
    rule <redacted> {
	iface lan0
    }
}

and got

# ps ax -o comm=,time=,etime=|grep ndp
ndproxy         00:00:03       28:12
ndppd           00:00:07       28:12