7eab7c352d
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.
141 lines
3.8 KiB
C
141 lines
3.8 KiB
C
/*-
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* Copyright (c) 2007-2008 Sam Leffler, Errno Consulting
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifdef __FreeBSD__
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__FBSDID("$FreeBSD$");
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#endif
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/*
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* IEEE 802.11 Monitor mode support.
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*/
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#include "opt_inet.h"
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#include "opt_wlan.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/malloc.h>
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#include <sys/kernel.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <sys/endian.h>
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#include <sys/errno.h>
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#include <sys/proc.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/if_media.h>
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#include <net/if_llc.h>
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#include <net/ethernet.h>
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#include <net/bpf.h>
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#include <net80211/ieee80211_var.h>
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#include <net80211/ieee80211_monitor.h>
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static void monitor_vattach(struct ieee80211vap *);
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static int monitor_newstate(struct ieee80211vap *, enum ieee80211_state, int);
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static int monitor_input(struct ieee80211_node *ni, struct mbuf *m,
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const struct ieee80211_rx_stats *rxs, int rssi, int nf);
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void
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ieee80211_monitor_attach(struct ieee80211com *ic)
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{
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ic->ic_vattach[IEEE80211_M_MONITOR] = monitor_vattach;
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}
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void
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ieee80211_monitor_detach(struct ieee80211com *ic)
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{
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}
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static void
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monitor_vdetach(struct ieee80211vap *vap)
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{
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}
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static void
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monitor_vattach(struct ieee80211vap *vap)
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{
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vap->iv_newstate = monitor_newstate;
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vap->iv_input = monitor_input;
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vap->iv_opdetach = monitor_vdetach;
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}
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/*
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* IEEE80211_M_MONITOR vap state machine handler.
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*/
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static int
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monitor_newstate(struct ieee80211vap *vap, enum ieee80211_state nstate, int arg)
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{
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struct ieee80211com *ic = vap->iv_ic;
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enum ieee80211_state ostate;
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IEEE80211_LOCK_ASSERT(ic);
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ostate = vap->iv_state;
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IEEE80211_DPRINTF(vap, IEEE80211_MSG_STATE, "%s: %s -> %s (%d)\n",
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__func__, ieee80211_state_name[ostate],
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ieee80211_state_name[nstate], arg);
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vap->iv_state = nstate; /* state transition */
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if (nstate == IEEE80211_S_RUN) {
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switch (ostate) {
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case IEEE80211_S_INIT:
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ieee80211_create_ibss(vap, ic->ic_curchan);
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break;
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default:
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break;
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}
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/*
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* NB: this shouldn't be here but many people use
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* monitor mode for raw packets; once we switch
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* them over to adhoc demo mode remove this.
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*/
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ieee80211_node_authorize(vap->iv_bss);
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}
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return 0;
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}
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/*
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* Process a received frame in monitor mode.
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*/
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static int
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monitor_input(struct ieee80211_node *ni, struct mbuf *m,
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const struct ieee80211_rx_stats *rxs, int rssi, int nf)
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{
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struct ieee80211vap *vap = ni->ni_vap;
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struct ifnet *ifp = vap->iv_ifp;
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if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
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if (ieee80211_radiotap_active_vap(vap))
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ieee80211_radiotap_rx(vap, m);
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m_freem(m);
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return -1;
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}
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