freebsd-skq/sys/net80211/ieee80211_node.c
sam 04780f09b9 Try yet again to deal with timing out nodes. We cannot hold the
node lock while sending a management frame as this will potentially
result in a LOR with a driver lock.  This doesn't happen for the
Atheros driver but does for the wi driver.  Use a generation number
to help process each node once when scanning the node table and
drop the node lock if we need to timeout a node and send a frame.
2003-09-26 17:00:44 +00:00

602 lines
17 KiB
C

/*-
* Copyright (c) 2001 Atsushi Onoe
* Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/bus.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <machine/atomic.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <net/if_llc.h>
#include <net80211/ieee80211_var.h>
#include <net/bpf.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/if_ether.h>
#endif
static struct ieee80211_node *ieee80211_node_alloc(struct ieee80211com *);
static void ieee80211_node_free(struct ieee80211com *, struct ieee80211_node *);
static void ieee80211_node_copy(struct ieee80211com *,
struct ieee80211_node *, const struct ieee80211_node *);
static u_int8_t ieee80211_node_getrssi(struct ieee80211com *,
struct ieee80211_node *);
static void ieee80211_setup_node(struct ieee80211com *ic,
struct ieee80211_node *ni, u_int8_t *macaddr);
static void _ieee80211_free_node(struct ieee80211com *,
struct ieee80211_node *);
MALLOC_DEFINE(M_80211_NODE, "node", "802.11 node state");
void
ieee80211_node_attach(struct ifnet *ifp)
{
struct ieee80211com *ic = (void *)ifp;
/* XXX need unit */
mtx_init(&ic->ic_nodelock, ifp->if_name, "802.11 node table", MTX_DEF);
TAILQ_INIT(&ic->ic_node);
ic->ic_node_alloc = ieee80211_node_alloc;
ic->ic_node_free = ieee80211_node_free;
ic->ic_node_copy = ieee80211_node_copy;
ic->ic_node_getrssi = ieee80211_node_getrssi;
ic->ic_scangen = 1;
}
void
ieee80211_node_lateattach(struct ifnet *ifp)
{
struct ieee80211com *ic = (void *)ifp;
ic->ic_bss = (*ic->ic_node_alloc)(ic);
KASSERT(ic->ic_bss != NULL, ("unable to setup inital BSS node"));
ic->ic_bss->ni_chan = IEEE80211_CHAN_ANYC;
}
void
ieee80211_node_detach(struct ifnet *ifp)
{
struct ieee80211com *ic = (void *)ifp;
if (ic->ic_bss != NULL)
(*ic->ic_node_free)(ic, ic->ic_bss);
ieee80211_free_allnodes(ic);
mtx_destroy(&ic->ic_nodelock);
}
/*
* AP scanning support.
*/
/*
* Initialize the active channel set based on the set
* of available channels and the current PHY mode.
*/
static void
ieee80211_reset_scan(struct ifnet *ifp)
{
struct ieee80211com *ic = (void *)ifp;
memcpy(ic->ic_chan_scan, ic->ic_chan_active,
sizeof(ic->ic_chan_active));
/* NB: hack, setup so next_scan starts with the first channel */
if (ic->ic_bss->ni_chan == IEEE80211_CHAN_ANYC)
ic->ic_bss->ni_chan = &ic->ic_channels[IEEE80211_CHAN_MAX];
}
/*
* Begin an active scan.
*/
void
ieee80211_begin_scan(struct ifnet *ifp)
{
struct ieee80211com *ic = (void *)ifp;
/*
* In all but hostap mode scanning starts off in
* an active mode before switching to passive.
*/
if (ic->ic_opmode != IEEE80211_M_HOSTAP)
ic->ic_flags |= IEEE80211_F_ASCAN;
if (ifp->if_flags & IFF_DEBUG)
if_printf(ifp, "begin %s scan\n",
(ic->ic_flags & IEEE80211_F_ASCAN) ?
"active" : "passive");
/*
* Clear scan state and flush any previously seen
* AP's. Note that the latter assumes we don't act
* as both an AP and a station, otherwise we'll
* potentially flush state of stations associated
* with us.
*/
ieee80211_reset_scan(ifp);
ieee80211_free_allnodes(ic);
/* Scan the next channel. */
ieee80211_next_scan(ifp);
}
/*
* Switch to the next channel marked for scanning.
*/
void
ieee80211_next_scan(struct ifnet *ifp)
{
struct ieee80211com *ic = (void *)ifp;
struct ieee80211_channel *chan;
chan = ic->ic_bss->ni_chan;
for (;;) {
if (++chan > &ic->ic_channels[IEEE80211_CHAN_MAX])
chan = &ic->ic_channels[0];
if (isset(ic->ic_chan_scan, ieee80211_chan2ieee(ic, chan))) {
/*
* Honor channels marked passive-only
* during an active scan.
*/
if ((ic->ic_flags & IEEE80211_F_ASCAN) == 0 ||
(chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0)
break;
}
if (chan == ic->ic_bss->ni_chan) {
ieee80211_end_scan(ifp);
return;
}
}
clrbit(ic->ic_chan_scan, ieee80211_chan2ieee(ic, chan));
IEEE80211_DPRINTF(("ieee80211_next_scan: chan %d->%d\n",
ieee80211_chan2ieee(ic, ic->ic_bss->ni_chan),
ieee80211_chan2ieee(ic, chan)));
ic->ic_bss->ni_chan = chan;
ieee80211_new_state(ic, IEEE80211_S_SCAN, -1);
}
void
ieee80211_create_ibss(struct ieee80211com* ic, struct ieee80211_channel *chan)
{
struct ieee80211_node *ni;
struct ifnet *ifp = &ic->ic_if;
ni = ic->ic_bss;
if (ifp->if_flags & IFF_DEBUG)
if_printf(ifp, "creating ibss\n");
ic->ic_flags |= IEEE80211_F_SIBSS;
ni->ni_chan = chan;
ni->ni_rates = ic->ic_sup_rates[ieee80211_chan2mode(ic, ni->ni_chan)];
IEEE80211_ADDR_COPY(ni->ni_macaddr, ic->ic_myaddr);
IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_myaddr);
if (ic->ic_opmode == IEEE80211_M_IBSS)
ni->ni_bssid[0] |= 0x02; /* local bit for IBSS */
ni->ni_esslen = ic->ic_des_esslen;
memcpy(ni->ni_essid, ic->ic_des_essid, ni->ni_esslen);
ni->ni_rssi = 0;
ni->ni_rstamp = 0;
memset(ni->ni_tstamp, 0, sizeof(ni->ni_tstamp));
ni->ni_intval = ic->ic_lintval;
ni->ni_capinfo = IEEE80211_CAPINFO_IBSS;
if (ic->ic_flags & IEEE80211_F_WEPON)
ni->ni_capinfo |= IEEE80211_CAPINFO_PRIVACY;
if (ic->ic_phytype == IEEE80211_T_FH) {
ni->ni_fhdwell = 200; /* XXX */
ni->ni_fhindex = 1;
}
ieee80211_new_state(ic, IEEE80211_S_RUN, -1);
}
/*
* Complete a scan of potential channels.
*/
void
ieee80211_end_scan(struct ifnet *ifp)
{
struct ieee80211com *ic = (void *)ifp;
struct ieee80211_node *ni, *nextbs, *selbs;
u_int8_t rate;
int i, fail;
ic->ic_flags &= ~IEEE80211_F_ASCAN;
ni = TAILQ_FIRST(&ic->ic_node);
if (ic->ic_opmode == IEEE80211_M_HOSTAP) {
/* XXX off stack? */
u_char occupied[roundup(IEEE80211_CHAN_MAX, NBBY)];
/*
* The passive scan to look for existing AP's completed,
* select a channel to camp on. Identify the channels
* that already have one or more AP's and try to locate
* an unnoccupied one. If that fails, pick a random
* channel from the active set.
*/
for (; ni != NULL; ni = nextbs) {
ieee80211_ref_node(ni);
nextbs = TAILQ_NEXT(ni, ni_list);
setbit(occupied, ieee80211_chan2ieee(ic, ni->ni_chan));
ieee80211_free_node(ic, ni);
}
for (i = 0; i < IEEE80211_CHAN_MAX; i++)
if (isset(ic->ic_chan_active, i) && isclr(occupied, i))
break;
if (i == IEEE80211_CHAN_MAX) {
fail = arc4random() & 3; /* random 0-3 */
for (i = 0; i < IEEE80211_CHAN_MAX; i++)
if (isset(ic->ic_chan_active, i) && fail-- == 0)
break;
}
ieee80211_create_ibss(ic, &ic->ic_channels[i]);
return;
}
if (ni == NULL) {
IEEE80211_DPRINTF(("%s: no scan candidate\n", __func__));
notfound:
if (ic->ic_opmode == IEEE80211_M_IBSS &&
(ic->ic_flags & IEEE80211_F_IBSSON) &&
ic->ic_des_esslen != 0) {
ieee80211_create_ibss(ic, ic->ic_ibss_chan);
return;
}
/*
* Reset the list of channels to scan and start again.
*/
ieee80211_reset_scan(ifp);
ieee80211_next_scan(ifp);
return;
}
selbs = NULL;
if (ifp->if_flags & IFF_DEBUG)
if_printf(ifp, "\tmacaddr bssid chan rssi rate flag wep essid\n");
for (; ni != NULL; ni = nextbs) {
ieee80211_ref_node(ni);
nextbs = TAILQ_NEXT(ni, ni_list);
if (ni->ni_fails) {
/*
* The configuration of the access points may change
* during my scan. So delete the entry for the AP
* and retry to associate if there is another beacon.
*/
if (ni->ni_fails++ > 2)
ieee80211_free_node(ic, ni);
continue;
}
fail = 0;
if (isclr(ic->ic_chan_active, ieee80211_chan2ieee(ic, ni->ni_chan)))
fail |= 0x01;
if (ic->ic_des_chan != IEEE80211_CHAN_ANYC &&
ni->ni_chan != ic->ic_des_chan)
fail |= 0x01;
if (ic->ic_opmode == IEEE80211_M_IBSS) {
if ((ni->ni_capinfo & IEEE80211_CAPINFO_IBSS) == 0)
fail |= 0x02;
} else {
if ((ni->ni_capinfo & IEEE80211_CAPINFO_ESS) == 0)
fail |= 0x02;
}
if (ic->ic_flags & IEEE80211_F_WEPON) {
if ((ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
fail |= 0x04;
} else {
if (ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY)
fail |= 0x04;
}
rate = ieee80211_fix_rate(ic, ni, IEEE80211_F_DONEGO);
if (rate & IEEE80211_RATE_BASIC)
fail |= 0x08;
if (ic->ic_des_esslen != 0 &&
(ni->ni_esslen != ic->ic_des_esslen ||
memcmp(ni->ni_essid, ic->ic_des_essid,
ic->ic_des_esslen != 0)))
fail |= 0x10;
if ((ic->ic_flags & IEEE80211_F_DESBSSID) &&
!IEEE80211_ADDR_EQ(ic->ic_des_bssid, ni->ni_bssid))
fail |= 0x20;
if (ifp->if_flags & IFF_DEBUG) {
printf(" %c %s", fail ? '-' : '+',
ether_sprintf(ni->ni_macaddr));
printf(" %s%c", ether_sprintf(ni->ni_bssid),
fail & 0x20 ? '!' : ' ');
printf(" %3d%c", ieee80211_chan2ieee(ic, ni->ni_chan),
fail & 0x01 ? '!' : ' ');
printf(" %+4d", ni->ni_rssi);
printf(" %2dM%c", (rate & IEEE80211_RATE_VAL) / 2,
fail & 0x08 ? '!' : ' ');
printf(" %4s%c",
(ni->ni_capinfo & IEEE80211_CAPINFO_ESS) ? "ess" :
(ni->ni_capinfo & IEEE80211_CAPINFO_IBSS) ? "ibss" :
"????",
fail & 0x02 ? '!' : ' ');
printf(" %3s%c ",
(ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) ?
"wep" : "no",
fail & 0x04 ? '!' : ' ');
ieee80211_print_essid(ni->ni_essid, ni->ni_esslen);
printf("%s\n", fail & 0x10 ? "!" : "");
}
if (!fail) {
if (selbs == NULL)
selbs = ni;
else if (ni->ni_rssi > selbs->ni_rssi) {
ieee80211_unref_node(&selbs);
selbs = ni;
} else
ieee80211_unref_node(&ni);
} else {
ieee80211_unref_node(&ni);
}
}
if (selbs == NULL)
goto notfound;
(*ic->ic_node_copy)(ic, ic->ic_bss, selbs);
if (ic->ic_opmode == IEEE80211_M_IBSS) {
ieee80211_fix_rate(ic, ic->ic_bss, IEEE80211_F_DOFRATE |
IEEE80211_F_DONEGO | IEEE80211_F_DODEL);
if (ic->ic_bss->ni_rates.rs_nrates == 0) {
selbs->ni_fails++;
ieee80211_unref_node(&selbs);
goto notfound;
}
ieee80211_unref_node(&selbs);
ieee80211_new_state(ic, IEEE80211_S_RUN, -1);
} else {
ieee80211_unref_node(&selbs);
ieee80211_new_state(ic, IEEE80211_S_AUTH, -1);
}
}
static struct ieee80211_node *
ieee80211_node_alloc(struct ieee80211com *ic)
{
return malloc(sizeof(struct ieee80211_node), M_80211_NODE,
M_NOWAIT | M_ZERO);
}
static void
ieee80211_node_free(struct ieee80211com *ic, struct ieee80211_node *ni)
{
free(ni, M_80211_NODE);
}
static void
ieee80211_node_copy(struct ieee80211com *ic,
struct ieee80211_node *dst, const struct ieee80211_node *src)
{
*dst = *src;
}
static u_int8_t
ieee80211_node_getrssi(struct ieee80211com *ic, struct ieee80211_node *ni)
{
return ni->ni_rssi;
}
static void
ieee80211_setup_node(struct ieee80211com *ic,
struct ieee80211_node *ni, u_int8_t *macaddr)
{
int hash;
IEEE80211_ADDR_COPY(ni->ni_macaddr, macaddr);
hash = IEEE80211_NODE_HASH(macaddr);
ni->ni_refcnt = 1; /* mark referenced */
mtx_lock(&ic->ic_nodelock);
TAILQ_INSERT_TAIL(&ic->ic_node, ni, ni_list);
LIST_INSERT_HEAD(&ic->ic_hash[hash], ni, ni_hash);
/*
* Note we don't enable the inactive timer when acting
* as a station. Nodes created in this mode represent
* AP's identified while scanning. If we time them out
* then several things happen: we can't return the data
* to users to show the list of AP's we encountered, and
* more importantly, we'll incorrectly deauthenticate
* ourself because the inactivity timer will kick us off.
*/
if (ic->ic_opmode != IEEE80211_M_STA)
ic->ic_inact_timer = IEEE80211_INACT_WAIT;
mtx_unlock(&ic->ic_nodelock);
}
struct ieee80211_node *
ieee80211_alloc_node(struct ieee80211com *ic, u_int8_t *macaddr)
{
struct ieee80211_node *ni = (*ic->ic_node_alloc)(ic);
if (ni != NULL)
ieee80211_setup_node(ic, ni, macaddr);
return ni;
}
struct ieee80211_node *
ieee80211_dup_bss(struct ieee80211com *ic, u_int8_t *macaddr)
{
struct ieee80211_node *ni = (*ic->ic_node_alloc)(ic);
if (ni != NULL) {
memcpy(ni, ic->ic_bss, sizeof(struct ieee80211_node));
ieee80211_setup_node(ic, ni, macaddr);
}
return ni;
}
struct ieee80211_node *
ieee80211_find_node(struct ieee80211com *ic, u_int8_t *macaddr)
{
struct ieee80211_node *ni;
int hash;
hash = IEEE80211_NODE_HASH(macaddr);
mtx_lock(&ic->ic_nodelock);
LIST_FOREACH(ni, &ic->ic_hash[hash], ni_hash) {
if (IEEE80211_ADDR_EQ(ni->ni_macaddr, macaddr)) {
atomic_add_int(&ni->ni_refcnt, 1); /* mark referenced */
break;
}
}
mtx_unlock(&ic->ic_nodelock);
return ni;
}
/*
* Like find but search based on the channel too.
*/
struct ieee80211_node *
ieee80211_lookup_node(struct ieee80211com *ic,
u_int8_t *macaddr, struct ieee80211_channel *chan)
{
struct ieee80211_node *ni;
int hash;
hash = IEEE80211_NODE_HASH(macaddr);
mtx_lock(&ic->ic_nodelock);
LIST_FOREACH(ni, &ic->ic_hash[hash], ni_hash) {
if (IEEE80211_ADDR_EQ(ni->ni_macaddr, macaddr) && ni->ni_chan == chan) {
atomic_add_int(&ni->ni_refcnt, 1);/* mark referenced */
break;
}
}
mtx_unlock(&ic->ic_nodelock);
return ni;
}
static void
_ieee80211_free_node(struct ieee80211com *ic, struct ieee80211_node *ni)
{
KASSERT(ni != ic->ic_bss, ("freeing bss node"));
TAILQ_REMOVE(&ic->ic_node, ni, ni_list);
LIST_REMOVE(ni, ni_hash);
if (TAILQ_EMPTY(&ic->ic_node))
ic->ic_inact_timer = 0;
(*ic->ic_node_free)(ic, ni);
}
void
ieee80211_free_node(struct ieee80211com *ic, struct ieee80211_node *ni)
{
KASSERT(ni != ic->ic_bss, ("freeing ic_bss"));
/* XXX need equivalent of atomic_dec_and_test */
atomic_subtract_int(&ni->ni_refcnt, 1);
if (atomic_cmpset_int(&ni->ni_refcnt, 0, 1)) {
mtx_lock(&ic->ic_nodelock);
_ieee80211_free_node(ic, ni);
mtx_unlock(&ic->ic_nodelock);
}
}
void
ieee80211_free_allnodes(struct ieee80211com *ic)
{
struct ieee80211_node *ni;
mtx_lock(&ic->ic_nodelock);
while ((ni = TAILQ_FIRST(&ic->ic_node)) != NULL)
_ieee80211_free_node(ic, ni);
mtx_unlock(&ic->ic_nodelock);
}
/*
* Timeout inactive nodes. Note that we cannot hold the node
* lock while sending a frame as this would lead to a LOR.
* Instead we use a generation number to mark nodes that we've
* scanned and drop the lock and restart a scan if we have to
* time out a node. Since we are single-threaded by virtue of
* controlling the inactivity timer we can be sure this will
* process each node only once.
*/
void
ieee80211_timeout_nodes(struct ieee80211com *ic)
{
struct ieee80211_node *ni;
u_int gen = ic->ic_scangen++; /* NB: ok 'cuz single-threaded*/
restart:
mtx_lock(&ic->ic_nodelock);
TAILQ_FOREACH(ni, &ic->ic_node, ni_list) {
if (ni->ni_scangen == gen) /* previously handled */
continue;
ni->ni_scangen = gen;
if (++ni->ni_inact > IEEE80211_INACT_MAX) {
IEEE80211_DPRINTF(("station %s timed out "
"due to inactivity (%u secs)\n",
ether_sprintf(ni->ni_macaddr),
ni->ni_inact));
/*
* Send a deauthenticate frame.
*
* Drop the node lock before sending the
* deauthentication frame in case the driver takes
* a lock, as this will result in a LOR between the
* node lock and the driver lock.
*/
mtx_unlock(&ic->ic_nodelock);
IEEE80211_SEND_MGMT(ic, ni,
IEEE80211_FC0_SUBTYPE_DEAUTH,
IEEE80211_REASON_AUTH_EXPIRE);
ieee80211_free_node(ic, ni);
goto restart;
}
}
if (!TAILQ_EMPTY(&ic->ic_node))
ic->ic_inact_timer = IEEE80211_INACT_WAIT;
mtx_unlock(&ic->ic_nodelock);
}
void
ieee80211_iterate_nodes(struct ieee80211com *ic, ieee80211_iter_func *f, void *arg)
{
struct ieee80211_node *ni;
mtx_lock(&ic->ic_nodelock);
TAILQ_FOREACH(ni, &ic->ic_node, ni_list)
(*f)(arg, ni);
mtx_unlock(&ic->ic_nodelock);
}