How to get global scope IPv6?

Help
1

I have problems getting a global unicast IPv6 address for given RIOT examples on gcoap and nanocoap_server. The output looks slightly different to the given examples and there is no scope global address given:

main(): This is RIOT! (Version: 2020.10-devel-326-gd187e8-HEAD)
RIOT nanocoap example application
Waiting for address autoconfiguration...
Configured network interfaces:
Iface  5  HWaddr: 56:96:42:41:9E:A3 
          L2-PDU:1500 MTU:1500  HL:64  Source address length: 6
          Link type: wired
          inet6 addr: fe80::5496:42ff:fe41:9ea3  scope: link  VAL
          inet6 group: ff02::1
          inet6 group: ff02::1:ff41:9ea3

It seems that there is no IPv6 connection to the router.

By using an Arduino MKR1000 it properly connects to the WiFi

[atwinc15x0] WiFi connected

but there is no network layer connection, just the hardware address seems to be exchanged.

Would be very nice if someone could help me :slight_smile:

2

What board are you using? Nvm, I didn’t read your post properly the first time. So you’re using the Arduino MKR1000 to connect to your router over Wifi, is that correct?

I think you’ll need to configure the global address manually using ifconfig from the RIOT shell. With the gcoap example, ifconfig 6 add 2001:db8::1 should add global address 2001:db8::1 to interface 6 of the RIOT node/board. Other than that, your router must have ipv6 enabled too.

3

That is correct, but I have the same problem on board native.

I’m able to add a global address on native

Iface  6  HWaddr: 32:D4:1E:E4:3B:81 
      L2-PDU:1500 MTU:1500  HL:64  Source address length: 6
      Link type: wired
      inet6 addr: fe80::30d4:1eff:fee4:3b81  scope: link  VAL
      inet6 addr: 2003:d1:8f2c:6001::3  scope: global  VAL
      inet6 group: ff02::1
      inet6 group: ff02::1:ffe4:3b81
      inet6 group: ff02::1:ff00:3

A request via the scope link address is successful

coap-client -N -m get -p 5683 coap://[fe80::30d4:1eff:fee4:3b81%tap0]/riot/board

But a request via the new scope global address gives the error

4.04 Not Found

or if I did not add this address to the tap0 interface then I do not receive any answer.

4

How do you create tap0? Does tap0 has a global address defined to it?

When using the tapsetup script ( RIOT/dist/tools/tapsetup/tapsetup), I managed to send a request using tapbr0 with the scope link address. For the scope global address I need to add a global ipv6 address to the tapbr0 interface first.

This is how I tested locally:

# RIOT shell
> ifconfig 6 add 2001:db8::1
> ifconfig
ifconfig
Iface  6  HWaddr: C6:60:20:A2:15:7F 
          L2-PDU:1500  MTU:1500  HL:64  Source address length: 6
          Link type: wired
          inet6 addr: fe80::c460:20ff:fea2:157f  scope: link  VAL
          inet6 addr: 2001:db8::1  scope: global  VAL
          inet6 group: ff02::1
          inet6 group: ff02::1:ffa2:157f
          inet6 group: ff02::1:ff00:1

# Local machine

## using scope link
$  coap-client -v6 -N -m get -p 5683 coap://[fe80::c460:20ff:fea2:157f%tapbr0]/riot/board
v:1 t:NON c:GET i:f01b {} [ Uri-Host:fe80::c460:20ff:fea2:157f%tapbr0, Uri-Path:riot, Uri-Path:board ]
v:1 t:NON c:2.05 i:f01b {} [ Content-Format:text/plain ] :: 'native'
native

## add global ipv6 to tapbr0
$ sudo ip -6 a add 2001:db8::2/64 dev tapbr0

## using scope global
$ coap-client -v6 -N -m get -p 5683 coap://[2001:db8::1]/riot/board
v:1 t:NON c:GET i:fd2c {} [ Uri-Path:riot, Uri-Path:board ]
v:1 t:NON c:2.05 i:fd2c {} [ Content-Format:text/plain ] :: 'native'
native
5

Additionally to what @pokgak wrote:

If you are on native, it is quite useful to configure your host as router. Otherwise it will not forward the packets coming from your router.

in /etc/sysctl.conf:

net.ipv6.conf.all.accept_ra=2
net.ipv6.conf.all.forwarding=1
net.ipv6.conf.all.accept_ra_defrtr=1
net.ipv6.conf.all.router_solicitations=1

Additionally to that I would also configure radvd. If you configured everything, you are able to send it from anywhere in your network. Not only the host system where the process is running.

6

Are you sure all those options need to be set for all interfaces? See also #14689.

7

No, you don’t need to. Maybe I should elaborate, that you can replace all with the interfaces you want to route. Thanks for pointing this out.

1 Like
8

For more info one should also refer to Linux’ doc on those configuration variables :slight_smile: (just was looking them up for a project of mine ^^).

1 Like
9

Thanks for all the helpful answers :smiley:

Unfortunately I can’t test it at the moment. I’ll give you feedback as soon as possible.