/* * Return the hardware NextTBTT in TSF */ uint64_t ar5210GetNextTBTT(struct ath_hal *ah) { #define TU_TO_TSF(_tu) (((uint64_t)(_tu)) << 10) return TU_TO_TSF(OS_REG_READ(ah, AR_TIMER0)); #undef TU_TO_TSF }
/* * Intercept management frames to collect beacon rssi data * and to do ibss merges. */ void ath_recv_mgmt(struct ieee80211_node *ni, struct mbuf *m, int subtype, const struct ieee80211_rx_stats *rxs, int rssi, int nf) { struct ieee80211vap *vap = ni->ni_vap; struct ath_softc *sc = vap->iv_ic->ic_softc; uint64_t tsf_beacon_old, tsf_beacon; uint64_t nexttbtt; int64_t tsf_delta; int32_t tsf_delta_bmiss; int32_t tsf_remainder; uint64_t tsf_beacon_target; int tsf_intval; tsf_beacon_old = ((uint64_t) le32dec(ni->ni_tstamp.data + 4)) << 32; tsf_beacon_old |= le32dec(ni->ni_tstamp.data); #define TU_TO_TSF(_tu) (((u_int64_t)(_tu)) << 10) tsf_intval = 1; if (ni->ni_intval > 0) { tsf_intval = TU_TO_TSF(ni->ni_intval); } #undef TU_TO_TSF /* * Call up first so subsequent work can use information * potentially stored in the node (e.g. for ibss merge). */ ATH_VAP(vap)->av_recv_mgmt(ni, m, subtype, rxs, rssi, nf); switch (subtype) { case IEEE80211_FC0_SUBTYPE_BEACON: /* * Only do the following processing if it's for * the current BSS. * * In scan and IBSS mode we receive all beacons, * which means we need to filter out stuff * that isn't for us or we'll end up constantly * trying to sync / merge to BSSes that aren't * actually us. */ if (IEEE80211_ADDR_EQ(ni->ni_bssid, vap->iv_bss->ni_bssid)) { /* update rssi statistics for use by the hal */ /* XXX unlocked check against vap->iv_bss? */ ATH_RSSI_LPF(sc->sc_halstats.ns_avgbrssi, rssi); tsf_beacon = ((uint64_t) le32dec(ni->ni_tstamp.data + 4)) << 32; tsf_beacon |= le32dec(ni->ni_tstamp.data); nexttbtt = ath_hal_getnexttbtt(sc->sc_ah); /* * Let's calculate the delta and remainder, so we can see * if the beacon timer from the AP is varying by more than * a few TU. (Which would be a huge, huge problem.) */ tsf_delta = (long long) tsf_beacon - (long long) tsf_beacon_old; tsf_delta_bmiss = tsf_delta / tsf_intval; /* * If our delta is greater than half the beacon interval, * let's round the bmiss value up to the next beacon * interval. Ie, we're running really, really early * on the next beacon. */ if (tsf_delta % tsf_intval > (tsf_intval / 2)) tsf_delta_bmiss ++; tsf_beacon_target = tsf_beacon_old + (((unsigned long long) tsf_delta_bmiss) * (long long) tsf_intval); /* * The remainder using '%' is between 0 .. intval-1. * If we're actually running too fast, then the remainder * will be some large number just under intval-1. * So we need to look at whether we're running * before or after the target beacon interval * and if we are, modify how we do the remainder * calculation. */ if (tsf_beacon < tsf_beacon_target) { tsf_remainder = -(tsf_intval - ((tsf_beacon - tsf_beacon_old) % tsf_intval)); } else { tsf_remainder = (tsf_beacon - tsf_beacon_old) % tsf_intval; } DPRINTF(sc, ATH_DEBUG_BEACON, "%s: old_tsf=%llu, new_tsf=%llu, target_tsf=%llu, delta=%lld, bmiss=%d, remainder=%d\n", __func__, (unsigned long long) tsf_beacon_old, (unsigned long long) tsf_beacon, (unsigned long long) tsf_beacon_target, (long long) tsf_delta, tsf_delta_bmiss, tsf_remainder); DPRINTF(sc, ATH_DEBUG_BEACON, "%s: tsf=%llu, nexttbtt=%llu, delta=%d\n", __func__, (unsigned long long) tsf_beacon, (unsigned long long) nexttbtt, (int32_t) tsf_beacon - (int32_t) nexttbtt + tsf_intval); /* We only do syncbeacon on STA VAPs; not on IBSS */ if (vap->iv_opmode == IEEE80211_M_STA && sc->sc_syncbeacon && ni == vap->iv_bss && (vap->iv_state == IEEE80211_S_RUN || vap->iv_state == IEEE80211_S_SLEEP)) { DPRINTF(sc, ATH_DEBUG_BEACON, "%s: syncbeacon=1; syncing\n", __func__); /* * Resync beacon timers using the tsf of the beacon * frame we just received. */ ath_beacon_config(sc, vap); sc->sc_syncbeacon = 0; } } /* fall thru... */ case IEEE80211_FC0_SUBTYPE_PROBE_RESP: if (vap->iv_opmode == IEEE80211_M_IBSS && vap->iv_state == IEEE80211_S_RUN && ieee80211_ibss_merge_check(ni)) { uint32_t rstamp = sc->sc_lastrs->rs_tstamp; uint64_t tsf = ath_extend_tsf(sc, rstamp, ath_hal_gettsf64(sc->sc_ah)); /* * Handle ibss merge as needed; check the tsf on the * frame before attempting the merge. The 802.11 spec * says the station should change it's bssid to match * the oldest station with the same ssid, where oldest * is determined by the tsf. Note that hardware * reconfiguration happens through callback to * ath_newstate as the state machine will go from * RUN -> RUN when this happens. */ if (le64toh(ni->ni_tstamp.tsf) >= tsf) { DPRINTF(sc, ATH_DEBUG_STATE, "ibss merge, rstamp %u tsf %ju " "tstamp %ju\n", rstamp, (uintmax_t)tsf, (uintmax_t)ni->ni_tstamp.tsf); (void) ieee80211_ibss_merge(ni); } } break; } }