Without this the first packet to a new link-local address will not be
delivered in non-6Lo environments, since the interface is not provided.
With this change, if an internet was provided to the address resolver it
will be stored within an allocated `gnrc_netif_hdr_t`.
At this point [IPv6 already striped](netif strip) the packet of its
netif header, so there is no risk that there will be to, in case it was
provided and the `netif` came from its existence.
Our `gnrc_minimal` example configures the link-local address from the
IEEE 802.15.4 short address since it does not include 6Lo-ND.
This causes the application to be incompatible with our other GNRC
application that do include 6Lo-ND, since it [assumes][1] the link-local
address to be based on the EUI-64 for address resolution.
This enforces long addresses (aka EUI-64) for all IEEE 802.15.4 devices
when IPv6 is compiled in so `gnrc_minimal` is compatible again to the
rest.
Fixes#9910
[1]: https://tools.ietf.org/html/rfc6775#section-5.2
Linux doesn't have ARO support at the moment so this is a workaround to
try to speak 6Lo-ND while still being able to do DAD with a border
router that doesn't.
Parts of [RFC4862] were already implemented when NDP via the NIB was
first implemented. This change just includes the DAD portion of
[RFC4862]. This should be enough to make RIOT fully RFC4862 compliant.
[RFC4862]: https://tools.ietf.org/html/rfc4862
With the previous fix, we only have to register addresses that are not
VALID yet on reception of router advertisements. This removes the need
for the hacky `GNRC_NETIF_FLAGS_6LO_ADDRS_REG` flag that was only
introduced to prevent unnecessary re-registration.
The whole address registration looses its point if all addresses are
marked valid from the get-go. With this fix non-link-local addresses
are first marked TENTATIVE and only after successful registration
marked as VALID. Link-local addresses are assumed to always be VALID.
[RFC6775] only talks of *routers* processing router advertisements,
with regards of discarding them if they do not contain an ABRO.
Additionally, this change makes configuration of tests setups a lot
easier, where one note is a router distributing a prefix and the other
is a host to be configured with the RA. Just do the following on the
router:
```
> ifconfig <if> add <GUA>
> ifconfig <if> rtr_adv
```
e voilà! In current master both nodes would have needed to be compiled
with `GNRC_IPV6_NIB_CONF_MULTIHOP_P6C=0`.
[RFC6775]: https://tools.ietf.org/html/rfc6775#section-8.1.3
This fix
* assures that the periodicity of the final router advertisements is
kept (so that no administrative change e.g. adding prefixes to the
prefix list causes additional RAs outside the rate limitation)
* removes all administrative options (PIO, ABRO, 6CO) from final router
advertisements (with router lifetime == 0)
I applied the following terminology and changed the wording in the doc
accordingly:
* must not: If the parameter is of the value it *must not* be it either
hits an assert or crashes the system.
* may not: The value can be that value, but the function will return an
error.
This renames the following functions
* `gnrc_netif_ipv6_addr_add()`
* `gnrc_netif_ipv6_addr_remove()`
* `gnrc_netif_ipv6_group_join()`
* `gnrc_netif_ipv6_group_leave()`
by appending the suffix `_internal`.
\## Reasoning
I'd like to provide a helper function for the *public* equivalent using
`gnrc_netapi_set()`, and those names are to nice to not be taken for
those.
\## Procedure
I used a combination of `git grep` and `sed` to do this and fixed the
alignment in the result of some cases by hand.
```sh
git grep --name-only "\<gnrc_netif_ipv6_\(addr\|group\)_\(add\|remove\|join\|leave\)\>" | \
xargs sed -i 's/\<gnrc_netif_ipv6_\(addr\|group\)_\(add\|remove\|join\|leave\)/\0_internal/g'
```
When a neighbor becomes UNREACHABLE which causes neighbor solicitations
to be send only up to every minute. If the medium is very busy this can
easily get lost, basically causing the neighbor never to be reachable
again from the perspective of the sending node. To fix this the backoff
is reduced to its start value, every time a packet is sent to that
neighbor.
This assertion doesn't make any sense. The function is called by
_copy_and_handle_aro() on a router which causes `nce` to be NULL
(because there is no NCE known yet) and then the function called
directly after (_reg_addr_upstream()) checks if `nce` might be NULL and
creates an NCE if necessary.
