fe267a5590
Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. No functional change intended.
442 lines
12 KiB
C
442 lines
12 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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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 DFS/Radar 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/ethernet.h>
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#include <net80211/ieee80211_var.h>
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static MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state");
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static int ieee80211_nol_timeout = 30*60; /* 30 minutes */
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SYSCTL_INT(_net_wlan, OID_AUTO, nol_timeout, CTLFLAG_RW,
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&ieee80211_nol_timeout, 0, "NOL timeout (secs)");
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#define NOL_TIMEOUT msecs_to_ticks(ieee80211_nol_timeout*1000)
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static int ieee80211_cac_timeout = 60; /* 60 seconds */
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SYSCTL_INT(_net_wlan, OID_AUTO, cac_timeout, CTLFLAG_RW,
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&ieee80211_cac_timeout, 0, "CAC timeout (secs)");
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#define CAC_TIMEOUT msecs_to_ticks(ieee80211_cac_timeout*1000)
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/*
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DFS* In order to facilitate debugging, a couple of operating
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* modes aside from the default are needed.
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*
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* 0 - default CAC/NOL behaviour - ie, start CAC, place
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* channel on NOL list.
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* 1 - send CAC, but don't change channel or add the channel
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* to the NOL list.
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* 2 - just match on radar, don't send CAC or place channel in
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* the NOL list.
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*/
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static int ieee80211_dfs_debug = DFS_DBG_NONE;
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/*
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* This option must not be included in the default kernel
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* as it allows users to plainly disable CAC/NOL handling.
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*/
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#ifdef IEEE80211_DFS_DEBUG
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SYSCTL_INT(_net_wlan, OID_AUTO, dfs_debug, CTLFLAG_RW,
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&ieee80211_dfs_debug, 0, "DFS debug behaviour");
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#endif
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static int
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null_set_quiet(struct ieee80211_node *ni, u_int8_t *quiet_elm)
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{
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return ENOSYS;
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}
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void
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ieee80211_dfs_attach(struct ieee80211com *ic)
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{
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struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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callout_init_mtx(&dfs->nol_timer, IEEE80211_LOCK_OBJ(ic), 0);
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callout_init_mtx(&dfs->cac_timer, IEEE80211_LOCK_OBJ(ic), 0);
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ic->ic_set_quiet = null_set_quiet;
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}
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void
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ieee80211_dfs_detach(struct ieee80211com *ic)
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{
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/* NB: we assume no locking is needed */
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ieee80211_dfs_reset(ic);
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}
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void
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ieee80211_dfs_reset(struct ieee80211com *ic)
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{
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struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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int i;
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/* NB: we assume no locking is needed */
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/* NB: cac_timer should be cleared by the state machine */
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callout_drain(&dfs->nol_timer);
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for (i = 0; i < ic->ic_nchans; i++)
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ic->ic_channels[i].ic_state = 0;
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dfs->lastchan = NULL;
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}
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static void
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cac_timeout(void *arg)
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{
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struct ieee80211vap *vap = arg;
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struct ieee80211com *ic = vap->iv_ic;
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struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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int i;
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IEEE80211_LOCK_ASSERT(ic);
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if (vap->iv_state != IEEE80211_S_CAC) /* NB: just in case */
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return;
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/*
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* When radar is detected during a CAC we are woken
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* up prematurely to switch to a new channel.
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* Check the channel to decide how to act.
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*/
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if (IEEE80211_IS_CHAN_RADAR(ic->ic_curchan)) {
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ieee80211_notify_cac(ic, ic->ic_curchan,
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IEEE80211_NOTIFY_CAC_RADAR);
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if_printf(vap->iv_ifp,
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"CAC timer on channel %u (%u MHz) stopped due to radar\n",
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ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
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/* XXX clobbers any existing desired channel */
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/* NB: dfs->newchan may be NULL, that's ok */
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vap->iv_des_chan = dfs->newchan;
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/* XXX recursive lock need ieee80211_new_state_locked */
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ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
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} else {
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if_printf(vap->iv_ifp,
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"CAC timer on channel %u (%u MHz) expired; "
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"no radar detected\n",
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ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
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/*
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* Mark all channels with the current frequency
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* as having completed CAC; this keeps us from
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* doing it again until we change channels.
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*/
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for (i = 0; i < ic->ic_nchans; i++) {
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struct ieee80211_channel *c = &ic->ic_channels[i];
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if (c->ic_freq == ic->ic_curchan->ic_freq)
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c->ic_state |= IEEE80211_CHANSTATE_CACDONE;
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}
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ieee80211_notify_cac(ic, ic->ic_curchan,
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IEEE80211_NOTIFY_CAC_EXPIRE);
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ieee80211_cac_completeswitch(vap);
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}
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}
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/*
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* Initiate the CAC timer. The driver is responsible
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* for setting up the hardware to scan for radar on the
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* channnel, we just handle timing things out.
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*/
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void
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ieee80211_dfs_cac_start(struct ieee80211vap *vap)
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{
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struct ieee80211com *ic = vap->iv_ic;
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struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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IEEE80211_LOCK_ASSERT(ic);
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callout_reset(&dfs->cac_timer, CAC_TIMEOUT, cac_timeout, vap);
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if_printf(vap->iv_ifp, "start %d second CAC timer on channel %u (%u MHz)\n",
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ticks_to_secs(CAC_TIMEOUT),
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ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
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ieee80211_notify_cac(ic, ic->ic_curchan, IEEE80211_NOTIFY_CAC_START);
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}
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/*
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* Clear the CAC timer.
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*/
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void
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ieee80211_dfs_cac_stop(struct ieee80211vap *vap)
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{
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struct ieee80211com *ic = vap->iv_ic;
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struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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IEEE80211_LOCK_ASSERT(ic);
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/* NB: racey but not important */
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if (callout_pending(&dfs->cac_timer)) {
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if_printf(vap->iv_ifp, "stop CAC timer on channel %u (%u MHz)\n",
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ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq);
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ieee80211_notify_cac(ic, ic->ic_curchan,
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IEEE80211_NOTIFY_CAC_STOP);
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}
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callout_stop(&dfs->cac_timer);
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}
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void
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ieee80211_dfs_cac_clear(struct ieee80211com *ic,
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const struct ieee80211_channel *chan)
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{
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int i;
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for (i = 0; i < ic->ic_nchans; i++) {
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struct ieee80211_channel *c = &ic->ic_channels[i];
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if (c->ic_freq == chan->ic_freq)
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c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
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}
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}
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static void
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dfs_timeout(void *arg)
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{
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struct ieee80211com *ic = arg;
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struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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struct ieee80211_channel *c;
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int i, oldest, now;
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IEEE80211_LOCK_ASSERT(ic);
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now = oldest = ticks;
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for (i = 0; i < ic->ic_nchans; i++) {
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c = &ic->ic_channels[i];
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if (IEEE80211_IS_CHAN_RADAR(c)) {
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if (ieee80211_time_after_eq(now, dfs->nol_event[i]+NOL_TIMEOUT)) {
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c->ic_state &= ~IEEE80211_CHANSTATE_RADAR;
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if (c->ic_state & IEEE80211_CHANSTATE_NORADAR) {
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/*
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* NB: do this here so we get only one
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* msg instead of one for every channel
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* table entry.
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*/
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ic_printf(ic, "radar on channel %u "
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"(%u MHz) cleared after timeout\n",
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c->ic_ieee, c->ic_freq);
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/* notify user space */
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c->ic_state &=
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~IEEE80211_CHANSTATE_NORADAR;
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ieee80211_notify_radar(ic, c);
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}
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} else if (dfs->nol_event[i] < oldest)
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oldest = dfs->nol_event[i];
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}
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}
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if (oldest != now) {
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/* arrange to process next channel up for a status change */
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callout_schedule(&dfs->nol_timer, oldest + NOL_TIMEOUT - now);
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}
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}
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static void
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announce_radar(struct ieee80211com *ic, const struct ieee80211_channel *curchan,
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const struct ieee80211_channel *newchan)
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{
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if (newchan == NULL)
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ic_printf(ic, "radar detected on channel %u (%u MHz)\n",
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curchan->ic_ieee, curchan->ic_freq);
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else
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ic_printf(ic, "radar detected on channel %u (%u MHz), "
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"moving to channel %u (%u MHz)\n",
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curchan->ic_ieee, curchan->ic_freq,
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newchan->ic_ieee, newchan->ic_freq);
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}
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/*
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* Handle a radar detection event on a channel. The channel is
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* added to the NOL list and we record the time of the event.
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* Entries are aged out after NOL_TIMEOUT. If radar was
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* detected while doing CAC we force a state/channel change.
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* Otherwise radar triggers a channel switch using the CSA
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* mechanism (when the channel is the bss channel).
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*/
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void
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ieee80211_dfs_notify_radar(struct ieee80211com *ic, struct ieee80211_channel *chan)
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{
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struct ieee80211_dfs_state *dfs = &ic->ic_dfs;
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int i, now;
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IEEE80211_LOCK_ASSERT(ic);
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/*
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* If doing DFS debugging (mode 2), don't bother
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* running the rest of this function.
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*
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* Simply announce the presence of the radar and continue
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* along merrily.
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*/
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if (ieee80211_dfs_debug == DFS_DBG_NOCSANOL) {
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announce_radar(ic, chan, chan);
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ieee80211_notify_radar(ic, chan);
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return;
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}
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/*
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* Don't mark the channel and don't put it into NOL
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* if we're doing DFS debugging.
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*/
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if (ieee80211_dfs_debug == DFS_DBG_NONE) {
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/*
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* Mark all entries with this frequency. Notify user
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* space and arrange for notification when the radar
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* indication is cleared. Then kick the NOL processing
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* thread if not already running.
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*/
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now = ticks;
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for (i = 0; i < ic->ic_nchans; i++) {
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struct ieee80211_channel *c = &ic->ic_channels[i];
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if (c->ic_freq == chan->ic_freq) {
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c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE;
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c->ic_state |= IEEE80211_CHANSTATE_RADAR;
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dfs->nol_event[i] = now;
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}
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}
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ieee80211_notify_radar(ic, chan);
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chan->ic_state |= IEEE80211_CHANSTATE_NORADAR;
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if (!callout_pending(&dfs->nol_timer))
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callout_reset(&dfs->nol_timer, NOL_TIMEOUT,
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dfs_timeout, ic);
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}
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/*
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* If radar is detected on the bss channel while
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* doing CAC; force a state change by scheduling the
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* callout to be dispatched asap. Otherwise, if this
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* event is for the bss channel then we must quiet
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* traffic and schedule a channel switch.
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*
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* Note this allows us to receive notification about
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* channels other than the bss channel; not sure
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* that can/will happen but it's simple to support.
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*/
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if (chan == ic->ic_bsschan) {
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/* XXX need a way to defer to user app */
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/*
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* Don't flip over to a new channel if
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* we are currently doing DFS debugging.
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*/
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if (ieee80211_dfs_debug == DFS_DBG_NONE)
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dfs->newchan = ieee80211_dfs_pickchannel(ic);
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else
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dfs->newchan = chan;
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announce_radar(ic, chan, dfs->newchan);
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if (callout_pending(&dfs->cac_timer))
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callout_schedule(&dfs->cac_timer, 0);
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else if (dfs->newchan != NULL) {
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/* XXX mode 1, switch count 2 */
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/* XXX calculate switch count based on max
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switch time and beacon interval? */
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ieee80211_csa_startswitch(ic, dfs->newchan, 1, 2);
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} else {
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/*
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* Spec says to stop all transmissions and
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* wait on the current channel for an entry
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* on the NOL to expire.
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*/
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/*XXX*/
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ic_printf(ic, "%s: No free channels; waiting for entry "
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"on NOL to expire\n", __func__);
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}
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} else {
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/*
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* Issue rate-limited console msgs.
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*/
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if (dfs->lastchan != chan) {
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dfs->lastchan = chan;
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dfs->cureps = 0;
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announce_radar(ic, chan, NULL);
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} else if (ppsratecheck(&dfs->lastevent, &dfs->cureps, 1)) {
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announce_radar(ic, chan, NULL);
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}
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}
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}
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struct ieee80211_channel *
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ieee80211_dfs_pickchannel(struct ieee80211com *ic)
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{
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struct ieee80211_channel *c;
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int i, flags;
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uint16_t v;
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/*
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* Consult the scan cache first.
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*/
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flags = ic->ic_curchan->ic_flags & IEEE80211_CHAN_ALL;
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/*
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* XXX if curchan is HT this will never find a channel
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* XXX 'cuz we scan only legacy channels
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*/
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c = ieee80211_scan_pickchannel(ic, flags);
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if (c != NULL)
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return c;
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/*
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* No channel found in scan cache; select a compatible
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* one at random (skipping channels where radar has
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* been detected).
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*/
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get_random_bytes(&v, sizeof(v));
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v %= ic->ic_nchans;
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for (i = v; i < ic->ic_nchans; i++) {
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c = &ic->ic_channels[i];
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if (!IEEE80211_IS_CHAN_RADAR(c) &&
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(c->ic_flags & flags) == flags)
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return c;
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}
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for (i = 0; i < v; i++) {
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c = &ic->ic_channels[i];
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if (!IEEE80211_IS_CHAN_RADAR(c) &&
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(c->ic_flags & flags) == flags)
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return c;
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}
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ic_printf(ic, "HELP, no channel located to switch to!\n");
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return NULL;
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}
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