Commit Graph

7 Commits

Author SHA1 Message Date
Adrian Chadd
c79f192c09 Begin plumbing ieee80211_rx_stats through the receive path.
Smart NICs with firmware (eg wpi, iwn, the new atheros parts, the intel 7260
series, etc) support doing a lot of things in firmware.  This includes but
isn't limited to things like scanning, sending probe requests and receiving
probe responses.  However, net80211 doesn't know about any of this - it still
drives the whole scan/probe infrastructure itself.

In order to move towards suppoting smart NICs, the receive path needs to
know about the channel/details for each received packet.  In at least
the iwn and 7260 firmware (and I believe wpi, but I haven't tried it yet)
it will do the scanning, power-save and off-channel buffering for you -
all you need to do is handle receiving beacons and probe responses on
channels that aren't what you're currently on.  However the whole receive
path is peppered with ic->ic_curchan and manual scan/powersave handling.
The beacon parsing code also checks ic->ic_curchan to determine if the
received beacon is on the correct channel or not.[1]

So:

* add freq/ieee values to ieee80211_rx_stats;
* change ieee80211_parse_beacon() to accept the 'current' channel
  as an argument;
* modify the iv_input() and iv_recv_mgmt() methods to include the rx_stats;
* add a new method - ieee80211_lookup_channel_rxstats() - that looks up
  a channel based on the contents of ieee80211_rx_stats;
* if it exists, use it in the mgmt path to switch the current channel
  (which still defaults to ic->ic_curchan) over to something determined
  by rx_stats.

This is enough to kick-start scan offload support in the Intel 7260
driver that Rui/I are working on.  It also is a good start for scan
offload support for a handful of existing NICs (wpi, iwn, some USB
parts) and it'll very likely dramatically improve stability/performance
there.  It's not the whole thing - notably, we don't need to do powersave,
we should not scan all channels, and we should leave probe request sending
to the firmware and not do it ourselves.  But, this allows for continued
development on the above features whilst actually having a somewhat
working NIC.

TODO:

* Finish tidying up how the net80211 input path works.
  Right now ieee80211_input / ieee80211_input_all act as the top-level
  that everything feeds into; it should change so the MIMO input routines
  are those and the legacy routines are phased out.

* The band selection should be done by the driver, not by the net80211
  layer.

* ieee80211_lookup_channel_rxstats() only determines 11b or 11g channels
  for now - this is enough for scanning, but not 100% true in all cases.
  If we ever need to handle off-channel scan support for things like
  static-40MHz or static-80MHz, or turbo-G, or half/quarter rates,
  then we should extend this.

[1] This is a side effect of frequency-hopping and CCK modes - you
    can receive beacons when you think you're on a different channel.
    In particular, CCK (which is used by the low 11b rates, eg beacons!)
    is decodable from adjacent channels - just at a low SNR.
    FH is a side effect of having the hardware/firmware do the frequency
    hopping - it may pick up beacons transmitted from other FH networks
    that are in a different phase of hopping frequencies.
2015-05-25 16:37:41 +00:00
Sam Leffler
5463c4a485 Overhaul monitor mode handling:
o replace DLT_IEEE802_11 support in net80211 with DLT_IEEE802_11_RADIO
  and remove explicit bpf support from wireless drivers; drivers now
  use ieee80211_radiotap_attach to setup shared data structures that
  hold the radiotap header for each packet tx/rx
o remove rx timestamp from the rx path; it was used only by the tdma support
  for debugging and was mostly useless due to it being 32-bits and mostly
  unavailable
o track DLT_IEEE80211_RADIO bpf attachments and maintain per-vap and
  per-com state when there are active taps
o track the number of monitor mode vaps
o use bpf tap and monitor mode vap state to decide when to collect radiotap
  state and dispatch frames; drivers no longer explicitly directly check
  bpf state or use bpf calls to tap frames
o handle radiotap state updates on channel change in net80211; drivers
  should not do this (unless they bypass net80211 which is almost always
  a mistake)
o update various drivers to be more consistent/correct in handling radiotap
o update ral to include TSF in radiotap'd frames
o add promisc mode callback to wi

Reviewed by:	cbzimmer, rpaulo, thompsa
2009-05-20 20:00:40 +00:00
Sam Leffler
9d90db9307 o move tdma+superg protocol defs out of public view
o add #ifdef _KERNEL to superg+tdma include files so they can be used
  by user code to get the protocol defs
2009-03-26 21:29:03 +00:00
Sam Leffler
8c4e758a8b add linker sets for get/set ioctl handlers so optional net80211
code is isolated
2009-03-24 17:57:48 +00:00
Sam Leffler
f9b5a72f15 rate limit printfs for invalid tdma ie contents; probably want this to
be less than 1/sec
2009-03-18 19:38:39 +00:00
Sam Leffler
2bc3ce7732 Minor cleanups of tdma protocol handling:
o break out version-related code to simplify rev'ing the protocol
o add parameter validation macros so checks that appear multiple places
  are consistent (and easy to change)
o add protocol version check when looking for a scan candidate
o improve scan debug output format
o rewrite beacon update handling to calculate a bitmask of changed values
  and pass that down through the driver callback so drivers can optimize work
o do slot bounds check before use when parsing received beacons
2009-03-18 19:28:17 +00:00
Sam Leffler
10ad9a77f3 TDMA support for long distance point-to-point links using ath devices:
o add net80211 support for a tdma vap that is built on top of the
  existing adhoc-demo support
o add tdma scheduling of frame transmission to the ath driver; it's
  conceivable other devices might be capable of this too in which case
  they can make use of the 802.11 protocol additions etc.
o add minor bits to user tools that need to know: ifconfig to setup and
  configure, new statistics in athstats, and new debug mask bits

While the architecture can support >2 slots in a TDMA BSS the current
design is intended (and tested) for only 2 slots.

Sponsored by:	Intel
2009-01-08 17:12:47 +00:00