This adds support for netdevs implementing the new API that provides
`netdev_driver_t::confirm_send()`. This allows implementing netdevs
in an event based non-blocking fashion, making live of driver
developers a bit easier. In addition, `gnrc_tx_sync` will now throttle
users of `sock_udp_send()` so that they can only send datagrams as
fast as the network stack and hardware is able to send out.
Finally, this lays the groundwork to fetch TX statistics (such as
TX timestamps, reception of layer 2 ACKs/NACKs, etc.) from the network
devices.
A if `netdev_driver_t::confirm_send()` is provided, it provides the
new netdev API. However, detecting the API at runtime and handling
both API styles comes at a cost. This can be optimized in case only
new or only old style netdevs are in use.
To do so, this adds the pseudo modules `netdev_legacy_api` and
`netdev_new_api`. As right now no netdev actually implements the new
API, all netdevs pull in `netdev_legacy_api`. If `netdev_legacy_api` is
in used but `netdev_new_api` is not, we can safely assume at compile
time that only legacy netdevs are in use. Similar, if only
`netdev_new_api` is used, only support for the new API is needed. Only
when both are in use, run time checks are needed.
This provides two helper function to check for a netif if the
corresponding netdev implements the old or the new API. (With one
being the inverse of the other.) They are suitable for constant folding
when only new or only legacy devices are in use. Consequently, dead
branches should be eliminated by the optimizer.
These functions are independent from GNRC and can be used by stack-agnistoc
code.
Avoid pulling in a GNRC dependency by moving those two helper functions to
`netif`.
The old function names are kept as `static inline` wrapper functions to avoid
breaking API users.
Add a message bus where threads can listen for nib events.
Currently only the GNRC_IPV6_NIB_EVENT_ADDR_VALID event is
implemented which informs subscribers that an address got
valid.
Enabled by the gnrc_netif_events pseudo module. Using an internal event
loop within the gnrc_netif thread eliminates the risk of lost interrupts
and lets ISR events always be handled before any send/receive requests
from other threads are processed.
The events in the event loop is also a potential hook for MAC layers and
other link layer modules which may need to inject and process events
before any external IPC messages are handled.
Co-Authored-By: Koen Zandberg <koen@bergzand.net>
This the first step in moving the collection of layer 2 netstats from
the low level driver to a central location, ie. gnrc_netif, to avoid
code duplication.
Since especially the setter for `NETOPT_IPV6_ADDR` and the getter for
both `NETOPT_IPV6_ADDR` and `NETOPT_IPV6_GROUP` isn't that obvious, I
decided to provided a helper function for those `gnrc_netapi_get/_set`
operations.
