ieee80211_node.c

Linux下wifi实现

	if (vap->iv_flags & IEEE80211_F_PRIVACY) {
		if ((ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
			return 0;
	} else {
		/* XXX does this mean privacy is supported or required? */
		if (ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY)
			return 0;
	}
	rate = ieee80211_fix_rate(ni, IEEE80211_F_DONEGO | IEEE80211_F_DOFRATE);
	if (rate & IEEE80211_RATE_BASIC)
		return 0;
	if (vap->iv_des_nssid != 0 &&
	    !match_ssid(ni, vap->iv_des_nssid, vap->iv_des_ssid))
		return 0;
	if ((vap->iv_flags & IEEE80211_F_DESBSSID) &&
	    !IEEE80211_ADDR_EQ(vap->iv_des_bssid, ni->ni_bssid))
		return 0;
	return 1;
}

#ifdef IEEE80211_DEBUG
/*
 * Display node suitability/compatibility.
 */
static void
check_bss_debug(struct ieee80211vap *vap, struct ieee80211_node *ni)
{
	struct ieee80211com *ic = ni->ni_ic;
        u_int8_t rate;
        int fail;

	fail = 0;
	if (isclr(ic->ic_chan_active, ieee80211_chan2ieee(ic, ni->ni_chan)))
		fail |= 0x01;
	if (vap->iv_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 (vap->iv_flags & IEEE80211_F_PRIVACY) {
		if ((ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
			fail |= 0x04;
	} else {
		/* XXX does this mean privacy is supported or required? */
		if (ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY)
			fail |= 0x04;
	}
	rate = ieee80211_fix_rate(ni, IEEE80211_F_DONEGO | IEEE80211_F_DOFRATE);
	if (rate & IEEE80211_RATE_BASIC)
		fail |= 0x08;
	if (vap->iv_des_nssid != 0 &&
	    !match_ssid(ni, vap->iv_des_nssid, vap->iv_des_ssid))
		fail |= 0x10;
	if ((vap->iv_flags & IEEE80211_F_DESBSSID) &&
	    !IEEE80211_ADDR_EQ(vap->iv_des_bssid, ni->ni_bssid))
		fail |= 0x20;

	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 ? "!" : "");
}
#endif /* IEEE80211_DEBUG */
 
/*
 * Handle 802.11 ad hoc network merge.  The
 * convention, set by the Wireless Ethernet Compatibility Alliance
 * (WECA), is that an 802.11 station will change its BSSID to match
 * the "oldest" 802.11 ad hoc network, on the same channel, that
 * has the station's desired SSID.  The "oldest" 802.11 network
 * sends beacons with the greatest TSF timestamp.
 *
 * The caller is assumed to validate TSF's before attempting a merge.
 *
 * Return !0 if the BSSID changed, 0 otherwise.
 */
int
ieee80211_ibss_merge(struct ieee80211_node *ni)
{
	struct ieee80211vap *vap = ni->ni_vap;
	struct ieee80211com *ic = ni->ni_ic;

	if (ni == vap->iv_bss ||
	    IEEE80211_ADDR_EQ(ni->ni_bssid, vap->iv_bss->ni_bssid)) {
		/* unchanged, nothing to do */
		return 0;
	}
	if (!check_bss(vap, ni)) {
		/* capabilities mismatch */
		IEEE80211_DPRINTF(vap, IEEE80211_MSG_ASSOC,
		    "%s: merge failed, capabilities mismatch\n", __func__);
#ifdef IEEE80211_DEBUG
		if (ieee80211_msg_assoc(vap))
			check_bss_debug(vap, ni);
#endif
		vap->iv_stats.is_ibss_capmismatch++;
		return 0;
	}
	IEEE80211_DPRINTF(vap, IEEE80211_MSG_ASSOC,
		"%s: new bssid %s: %s preamble, %s slot time%s\n", __func__,
		ether_sprintf(ni->ni_bssid),
		ic->ic_flags & IEEE80211_F_SHPREAMBLE ? "short" : "long",
		ic->ic_flags & IEEE80211_F_SHSLOT ? "short" : "long",
		ic->ic_flags & IEEE80211_F_USEPROT ? ", protection" : "");
	return ieee80211_sta_join1(ieee80211_ref_node(ni));
}
EXPORT_SYMBOL(ieee80211_ibss_merge);

static __inline int
ssid_equal(const struct ieee80211_node *a, const struct ieee80211_node *b)
{
	return (a->ni_esslen == b->ni_esslen &&
		memcmp(a->ni_essid, b->ni_bssid, a->ni_esslen) == 0);
}

/*
 * Join the specified IBSS/BSS network.  The node is assumed to
 * be passed in with a reference already held for use in assigning
 * to iv_bss.
 */
static int
ieee80211_sta_join1(struct ieee80211_node *selbs)
{
	struct ieee80211vap *vap = selbs->ni_vap;
	struct ieee80211com *ic = selbs->ni_ic;
	struct ieee80211_node *obss;
	int canreassoc;

	if (vap->iv_opmode == IEEE80211_M_IBSS) {
		/*
		 * Delete unusable rates; we've already checked
		 * that the negotiated rate set is acceptable.
		 */
		ieee80211_fix_rate(selbs, IEEE80211_F_DODEL);
	}

	/*
	 * Committed to selbs, setup state.
	 */
	obss = vap->iv_bss;
	/*
	 * Check if old+new node have the same ssid in which
	 * case we can reassociate when operating in sta mode.
	 */
	canreassoc = (obss != NULL &&
		vap->iv_state == IEEE80211_S_RUN && ssid_equal(obss, selbs));
	vap->iv_bss = selbs;
	if (obss != NULL)
		ieee80211_free_node(obss);
	ic->ic_bsschan = selbs->ni_chan;
	ic->ic_curchan = ic->ic_bsschan;
	ic->ic_curmode = ieee80211_chan2mode(ic->ic_curchan);
	ic->ic_set_channel(ic);
	/*
	 * Set the erp state (mostly the slot time) to deal with
	 * the auto-select case; this should be redundant if the
	 * mode is locked.
	 */ 
	ieee80211_reset_erp(ic, ic->ic_curmode);
	ieee80211_wme_initparams(vap);

	if (vap->iv_opmode == IEEE80211_M_STA) {
		/*
		 * Act as if we received a DEAUTH frame in case we are
		 * invoked from the RUN state.  This will cause us to try
		 * to re-authenticate if we are operating as a station.
		 */
		if (canreassoc) {
			vap->iv_nsparams.newstate = IEEE80211_S_ASSOC;
			vap->iv_nsparams.arg = 0;
			IEEE80211_SCHEDULE_TQUEUE(&vap->iv_stajoin1tq);
		} else {
			vap->iv_nsparams.newstate = IEEE80211_S_AUTH;
			vap->iv_nsparams.arg = IEEE80211_FC0_SUBTYPE_DEAUTH;
			IEEE80211_SCHEDULE_TQUEUE(&vap->iv_stajoin1tq);
		}
	} else {
		vap->iv_nsparams.newstate = IEEE80211_S_RUN;
		vap->iv_nsparams.arg = -1;
		IEEE80211_SCHEDULE_TQUEUE(&vap->iv_stajoin1tq);
	}
	return 1;
}

void
ieee80211_sta_join1_tasklet(IEEE80211_TQUEUE_ARG data)
{
	struct ieee80211vap *vap= (struct ieee80211vap *) data;
	int rc;

	rc = ieee80211_new_state(vap, vap->iv_nsparams.newstate, vap->iv_nsparams.arg);
	vap->iv_nsparams.result = rc;
	vap->iv_nsdone = 1;
}
EXPORT_SYMBOL(ieee80211_sta_join1_tasklet);

int
ieee80211_sta_join(struct ieee80211vap *vap,
	const struct ieee80211_scan_entry *se)
{
	struct ieee80211com *ic = vap->iv_ic;
	struct ieee80211_node *ni;

	ni = ieee80211_find_node(&ic->ic_sta, se->se_macaddr);
	if (ni == NULL) {
		ni = ieee80211_alloc_node(&ic->ic_sta, vap, se->se_macaddr);
		if (ni == NULL) {
			/* XXX msg */
			return 0;
		}
	} else
		ieee80211_free_node(ni);

	/*
	 * Expand scan state into node's format.
	 * XXX may not need all this stuff
	 */
	ni->ni_authmode = vap->iv_bss->ni_authmode;		/* inherit authmode from iv_bss */
	/* inherit the WPA setup as well (structure copy!) */
	ni->ni_rsn = vap->iv_bss->ni_rsn; 
	IEEE80211_ADDR_COPY(ni->ni_bssid, se->se_bssid);
	ni->ni_esslen = se->se_ssid[1];
	memcpy(ni->ni_essid, se->se_ssid + 2, ni->ni_esslen);
	ni->ni_rstamp = se->se_rstamp;
	ni->ni_tstamp.tsf = se->se_tstamp.tsf;
	ni->ni_intval = se->se_intval;
	ni->ni_capinfo = se->se_capinfo;
	ni->ni_chan = se->se_chan;
	ni->ni_timoff = se->se_timoff;
	ni->ni_fhdwell = se->se_fhdwell;
	ni->ni_fhindex = se->se_fhindex;
	ni->ni_erp = se->se_erp;
	ni->ni_rssi = se->se_rssi;
	if (se->se_wpa_ie != NULL)
		ieee80211_saveie(&ni->ni_wpa_ie, se->se_wpa_ie);
	if (se->se_rsn_ie != NULL)
		ieee80211_saveie(&ni->ni_rsn_ie, se->se_rsn_ie);
	if (se->se_wme_ie != NULL)
		ieee80211_saveie(&ni->ni_wme_ie, se->se_wme_ie);
	if (se->se_ath_ie != NULL)
		ieee80211_saveath(ni, se->se_ath_ie);

	vap->iv_dtim_period = se->se_dtimperiod;
	vap->iv_dtim_count = 0;

	/* NB: must be after ni_chan is setup */
	ieee80211_setup_rates(ni, se->se_rates, se->se_xrates,
		IEEE80211_F_DOSORT | IEEE80211_F_DONEGO | IEEE80211_F_DODEL);

	IEEE80211_DPRINTF(vap, IEEE80211_MSG_NODE, 
	"%s: %p<%s> refcnt %d\n", __func__, ni, ether_sprintf(ni->ni_macaddr), 
	ieee80211_node_refcnt(ni)+1);

	return ieee80211_sta_join1(ieee80211_ref_node(ni));
}
EXPORT_SYMBOL(ieee80211_sta_join);

/*
 * Leave the specified IBSS/BSS network.  The node is assumed to
 * be passed in with a held reference.
 */
void
ieee80211_sta_leave(struct ieee80211_node *ni)
{
	struct ieee80211vap *vap = ni->ni_vap;
	struct ieee80211com *ic = vap->iv_ic;

	/* WDS/Repeater: Stop software beacon timer for STA */
	if (vap->iv_opmode == IEEE80211_M_STA &&
	    vap->iv_flags_ext & IEEE80211_FEXT_SWBMISS) {
		del_timer(&vap->iv_swbmiss);
	}

	ic->ic_node_cleanup(ni);
	ieee80211_notify_node_leave(ni);
}

/*
 * Node table support.
 */

static void
ieee80211_node_table_init(struct ieee80211com *ic,
	struct ieee80211_node_table *nt,	const char *name, int inact)
{
	nt->nt_ic = ic;
	IEEE80211_NODE_LOCK_INIT(nt, ic->ic_dev->name);
	IEEE80211_SCAN_LOCK_INIT(nt, ic->ic_dev->name);
	TAILQ_INIT(&nt->nt_node);
	nt->nt_name = name;
	nt->nt_scangen = 1;
	nt->nt_inact_init = inact;
	init_timer(&nt->nt_wds_aging_timer);
	nt->nt_wds_aging_timer.function = ieee80211_node_wds_ageout;
	nt->nt_wds_aging_timer.data = (unsigned long) nt;
	mod_timer(&nt->nt_wds_aging_timer, jiffies + HZ * WDS_AGING_TIMER_VAL);
}

static struct ieee80211_node *
node_alloc(struct ieee80211_node_table *nt, struct ieee80211vap *vap)
{
	struct ieee80211_node *ni;

	MALLOC(ni, struct ieee80211_node *, sizeof(struct ieee80211_node),
		M_80211_NODE, M_NOWAIT | M_ZERO);

	return ni;
}

/*
 * Reclaim any resources in a node and reset any critical
 * state.  Typically nodes are free'd immediately after,
 * but in some cases the storage may be reused so we need
 * to ensure consistent state (should probably fix that).
 *
 * Context: hwIRQ, softIRQ and process context
 */
static void
node_cleanup(struct ieee80211_node *ni)
{
#define	N(a)	(sizeof(a)/sizeof(a[0]))
	struct ieee80211vap *vap = ni->ni_vap;
	int i;

	/* NB: preserve ni_table */
	if (ni->ni_flags & IEEE80211_NODE_PWR_MGT) {
		if (vap->iv_opmode != IEEE80211_M_STA)
			vap->iv_ps_sta--;
		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
			"power save mode off, %u sta's in ps mode",
			vap->iv_ps_sta);

		if (ni->ni_flags & IEEE80211_NODE_UAPSD_TRIG) {
			ni->ni_flags &= ~IEEE80211_NODE_UAPSD_TRIG;
			IEEE80211_LOCK_IRQ(ni->ni_ic);
			ni->ni_ic->ic_uapsdmaxtriggers--;
			IEEE80211_UNLOCK_IRQ(ni->ni_ic);
		}
	}
	/*
	 * Clear AREF flag that marks the authorization refcnt bump
	 * has happened.  This is probably not needed as the node
	 * should always be removed from the table so not found but
	 * do it just in case.
	 */
	ni->ni_flags &= ~IEEE80211_NODE_AREF;

	/*
	 * Drain power save queue and, if needed, clear TIM.
	 */
	if (ieee80211_node_saveq_drain(ni) != 0 && vap->iv_set_tim != NULL)
		vap->iv_set_tim(ni, 0);

	ni->ni_associd = 0;
	if (ni->ni_challenge != NULL) {
		FREE(ni->ni_challenge, M_DEVBUF);
		ni->ni_challenge = NULL;
	}
	/*
	 * Preserve SSID, WPA, and WME ie's so the bss node is
	 * reusable during a re-auth/re-assoc state transition.
	 * If we remove these data they will not be recreated
	 * because they come from a probe-response or beacon frame
	 * which cannot be expected prior to the association-response.
	 * This should not be an issue when operating in other modes
	 * as stations leaving always go through a full state transition
	 * which will rebuild this state.
	 *
	 * XXX does this leave us open to inheriting old state?
	 */
	for (i = 0; i < N(ni->ni_rxfrag); i++)
		if (ni->ni_rxfrag[i] != NULL) {
			dev_kfree_skb_any(ni->ni_rxfrag[i]);
			ni->ni_rxfrag[i] = NULL;
		}
	ieee80211_crypto_delkey(vap, &ni->ni_ucastkey, ni);
	ni->ni_rxkeyoff = 0;
#undef N
}

static void
node_free(struct ieee80211_node *ni)
{
	struct ieee80211com *ic = ni->ni_ic;

	ic->ic_node_cleanup(ni);
	if (ni->ni_wpa_ie != NULL)
		FREE(ni->ni_wpa_ie, M_DEVBUF);
	if (ni->ni_rsn_ie != NULL)
		FREE(ni->ni_rsn_ie, M_DEVBUF);
	if (ni->ni_wme_ie != NULL)
		FREE(ni->ni_wme_ie, M_DEVBUF);
	if (ni->ni_ath_ie != NULL)
		FREE(ni->ni_ath_ie, M_DEVBUF);
	IEEE80211_NODE_SAVEQ_DESTROY(ni);
	FREE(ni, M_80211_NODE);
}

static u_int8_t
node_getrssi(const struct ieee80211_node *ni)
{