The comment exists since the introduction of the [original
implementation], but its meaning is unclear and misleading, as the code
doesn't do anything with link-local.
[original implementation]: https://github.com/RIOT-OS/RIOT/pull/3561
Rule 2 of the source address algorithm outlined in [RFC6724] states the
possible source addresses must also be compared among each other:
> Rule 2: Prefer appropriate scope.
> If Scope(SA) < Scope(SB): If Scope(SA) < Scope(D), then prefer SB and
> otherwise prefer SA. Similarly, if Scope(SB) < Scope(SA): If
> Scope(SB) < Scope(D), then prefer SA and otherwise prefer SB.
Our current implementation doesn't do that. It just checks if the scope
of a possible source is lesser than the scope of the destination
(which involves the second "If" in the rule).
This fix grants points according to the scope of an address. If the
scope matches, they get the highest points, ensuring that the selected
source will always be reachable from the destination.
[RFC6724]: https://tools.ietf.org/html/rfc6724
Having the definitions sit in the `net/gnrc/sixlowpan/frag.h` header
does not make much sense, when using Selective Fragment Forwarding
(and the fragmentation buffer already includes a
`net/gnrc/sixlowpan/frag/stats.h` header), so they are moved to their
own header. Since with this change it makes more sense to have the
statistics stored in their own sub-module, the pseudo-module is also
actualized.
A pointer is not 32 bit on all platforms.
Since gnrc_lwmac only stores 16 bit in the pointer variable it is
still save to cast like this even on AVR, but cast to uintptr_t
instead of uint32_t.
fixes#12869
When the destination address is the loopback address (`::1`) in GNRC
the selected network interface typically is `NULL`, as with GNRC no
loopback interface de facto exists. So the assertion when checking if
the source address is valid if `netif != NULL` fails on that check.
This change fixes that issue by checking if the destination address is
the loopback address, before checking the validity of the source
address.
The RTT callback for a super-frame cycle uses the `arg` pointer to set
the message value that then is handed to the GoMacH thread. However,
in both instances the timer is scheduled the constant
`GNRC_GOMACH_EVENT_RTT_NEW_CYCLE` is provided. This means the argument
is not really necessary.
This fits with the semantics of this function which doesn't provide or
uses any state of the reassembly buffer provided by the user, but finds
the entry itself and then removes it. This gives the user no chance to
remove the packet in the reassembly buffer entry, so
`gnrc_sixlowpan_frag_rb_rm_by_datagram()` has to release the packet
(other than `gnrc_sixlowpan_frag_rb_remove()` where not releasing the
packet is desired as it might be handed up to an upper layer).
Right now 'ipv6_addr_split_iface' assumes that the interface specifier
will always be a number (based on GNRC way of identifying interfaces),
but this may not be always the case.In order to be able to use the
Network Interface API, interfaces should be referred by their name.
This changes 'ipv6_addr_split_iface' so it returns a pointer to the
string that specifies the interface.
This allows to set a timer between the completion of a datagram in the
reassembly buffer and the deletion of the corresponding reassembly
buffer entry. This allows to ignore potentially late incoming link-layer
duplicates of fragments of the datagram that then will have the
reassembly buffer entry be blocked.
This was noted in this [discussion] for classic 6LoWPAN reassembly (and
minimal fragment forwarding) and is recommended in the current
[selective fragment recovery draft][SFR draft].
[discussion]: https://mailarchive.ietf.org/arch/msg/6lo/Ez0tzZDqawVn6AFhYzAFWUOtJns
[SFR draft]: https://tools.ietf.org/html/draft-ietf-6lo-fragment-recovery-07#section-6
As analyzed in #12678 there are cases where different reports can be
generated for the different snips of the packet send via the `sock`.
To catch all errors generated by the stack, the sock has to subscribe
for all snips of the packet sent. If any of the snips reports an error
distinct from `GNRC_NETERR_SUCCESS` or the previous one, we report that
status instead of just the first we receive. This way we are ensured to
have the first error reported by the stack for the given packet.
The name `fragment_msg` or `frag_msg`/`msg_frag` always to me was a bit
misplaced, as it basically implements an asynchronous fragmentation
buffer and doesn't necessarily have anything to do with messages.
This change
1. changes the name to `fb` (for fragmentation buffer)
2. factors its code out to its own sub-module so it can be re-used by
other 6LoWPAN fragmentation schemes like [Selective Fragment
Recovery]
[Selective Fragment Recovery]: https://tools.ietf.org/html/draft-ietf-6lo-fragment-recovery-05
The interface is already fetched in the beginning of the function and
doesn't change during its run, so getting the interface again at this
point is just redundant.
When decoding IPHC in a fragmented datagram, relying on the size of the
allocated space for the decoded packet is wrong when fragments are
forwarded and decoded on an intermediate node (for which the reassembly
buffer's space is used): Using the full datagram size for allocation in
this case would be wasteful, so the allocated space is only marginally
larger than the fragment's compressed form.
This in turn results in the wrong UDP payload size being chosen and
even worse being forwarded to the subsequent nodes.
This change uses the (virtual) reassembly buffer's `datagram_size`
instead of relying on the allocated space for the encoded
datagram/fragment.
`_match_to_idx()` was removed from source address selection (which was
the only one setting the filter parameter to a non-NULL value), so it
is the parameter is not needed anymore.
