tinyppp6

Tiny implementation of PPP for IPv6.

This project is a proof of concept to see how much work it is to build a minimal IPv6-only implementation of the Point-to-Point Protocol.

It is completely stand-alone process and does not interact with the kernel's network stack.

It has been tested against version 2.4.7 of Linux pppd (running on Debian Linux).

Features

• Responds to LCP pings
• Responds to IPv6 ICMP pings on link-local
• Rejects Unknown Protocols
• Prints out UDP packets sent to port 1234
• Connects using the pty option in Linux pppd

Not Implemented

• IPv4
• SLAAC
• DHCPv6
• Any header / protocol compression
• IPv6 Extension Headers are not supported
• TCP

Running tinyppp6

First compile tinyppp6 using the make command.

Use the following to start Linux pppd and connect it to a tinyppp6 sub-process:

sudo pppd \
 nodetach \
 noauth \
 noip \
 +ipv6 \
 ipv6 ::1,::2 \
 pty './src/tinyppp6'

The following Link-local IPv6 addresses will then be setup:

• fe80::1 - the Linux pppd end of the PPP connection
• fe80::2 - the tinyppp6 end of the PPP connection

You should then be able to send ICMPv6 pings to tinyppp6 using:

ping6 fe80::2%ppp0
PING fe80::2%ppp0(fe80::2%ppp0) 56 data bytes
64 bytes from fe80::2%ppp0: icmp_seq=1 ttl=64 time=0.588 ms
64 bytes from fe80::2%ppp0: icmp_seq=2 ttl=64 time=0.555 ms
64 bytes from fe80::2%ppp0: icmp_seq=3 ttl=64 time=0.645 ms
64 bytes from fe80::2%ppp0: icmp_seq=4 ttl=64 time=0.601 ms

And send UDP packets to tinyppp6 using:

echo -n "Hello World" | socat - UDP6:[fe80::2%ppp0]:1234