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bwfm fixes
On Mon, Aug 04, 2025 at 08:19:08PM +0200, Moritz Buhl wrote:
> Dear tech,
>
> I currently use a MacBook m2 and I always have trouble with the
> bwfm in it.
>
> Here are three fixes:
> 1. receive EAPOL event messages.
> After debugging this for a few days, I noticed that EAPOL frames
> do not cause an interrupt and with my macbook the messag either
> comes with the previous WL_EVENTS that change the link state and
> finish the ASSOC state, or the firmware crashes about 100ms later.
Nice find! I admire your persistence in tracking this down.
> I can imagine this may also help with crashes in AP mode on other
> devices.
>
> 2. do ieee80211 state changes inside of the interrupt handler.
> To my understanding this is in line with outher drivers and it is
> necessary for the wpa handshake to process it within 100 ms which
> we could miss because of the additional queueing.
>
> 3. process control messages before rx messages.
> Otherwise a EAPOL frame could be processed before changing from
> ASSOC to RUN.
>
> I would appreciate additional testing on other devices.
ok stsp@ with some suggestions below:
> Index: ic/bwfm.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/ic/bwfm.c,v
> diff -u -p -r1.111 bwfm.c
> --- ic/bwfm.c 19 Feb 2024 21:23:02 -0000 1.111
> +++ ic/bwfm.c 4 Aug 2025 15:43:12 -0000
> @@ -494,6 +494,7 @@ bwfm_init(struct ifnet *ifp)
> BWFM_EVENT(BWFM_E_LINK);
> BWFM_EVENT(BWFM_E_AUTH);
> BWFM_EVENT(BWFM_E_ASSOC);
> + BWFM_EVENT(BWFM_E_EAPOL_MSG);
> BWFM_EVENT(BWFM_E_DEAUTH);
> BWFM_EVENT(BWFM_E_DISASSOC);
> BWFM_EVENT(BWFM_E_ESCAN_RESULT);
> @@ -503,6 +504,7 @@ bwfm_init(struct ifnet *ifp)
> BWFM_EVENT(BWFM_E_AUTH_IND);
> BWFM_EVENT(BWFM_E_ASSOC_IND);
> BWFM_EVENT(BWFM_E_REASSOC_IND);
> + BWFM_EVENT(BWFM_E_EAPOL_MSG);
> BWFM_EVENT(BWFM_E_DEAUTH_IND);
> BWFM_EVENT(BWFM_E_DISASSOC_IND);
> BWFM_EVENT(BWFM_E_ESCAN_RESULT);
> @@ -2551,12 +2551,44 @@ void
> bwfm_rx_event(struct bwfm_softc *sc, struct mbuf *m)
> {
> int s;
> + struct ieee80211com *ic = &sc->sc_ic;
> + struct bwfm_event *e = mtod(m, void *);
>
> s = splnet();
> + switch (ntohl(e->msg.event_type)) {
> + case BWFM_E_AUTH:
> + if (ntohl(e->msg.status) == BWFM_E_STATUS_SUCCESS &&
> + ic->ic_state == IEEE80211_S_AUTH) {
> + ieee80211_new_state(ic, IEEE80211_S_ASSOC, -1);
> + goto done;
> + }
> + goto enqueue;
> + case BWFM_E_ASSOC:
> + if (ntohl(e->msg.status) == BWFM_E_STATUS_SUCCESS &&
> + ic->ic_state == IEEE80211_S_ASSOC) {
> + ieee80211_new_state(ic, IEEE80211_S_RUN, -1);
> + } else if (ntohl(e->msg.status) != BWFM_E_STATUS_UNSOLICITED) {
> + goto enqueue;
> + }
> + goto done;
> + case BWFM_E_LINK:
> + if (ntohl(e->msg.status) == BWFM_E_STATUS_SUCCESS &&
> + ntohl(e->msg.reason) == 0)
> + goto done;
> + goto enqueue;
> + default:
> + goto enqueue;
> + }
> +done:
> + splx(s);
> + m_freem(m);
> + return;
> +enqueue:
> ml_enqueue(&sc->sc_evml, m);
> splx(s);
>
> task_add(sc->sc_taskq, &sc->sc_task);
> + return;
Nitpick: The above 'return' is not strictly needed.
> }
>
> void
> @@ -2631,18 +2663,10 @@ bwfm_rx_event_cb(struct bwfm_softc *sc,
> break;
> }
> case BWFM_E_AUTH:
> - if (ntohl(e->msg.status) == BWFM_E_STATUS_SUCCESS &&
> - ic->ic_state == IEEE80211_S_AUTH)
> - ieee80211_new_state(ic, IEEE80211_S_ASSOC, -1);
> - else
> - ieee80211_begin_scan(ifp);
> + ieee80211_begin_scan(ifp);
This code handles the case where authentication to the AP has failed
and we need to try again (and potentially try a different AP).
This would be much more obvious if the begin_scan() call was guarded
by an appropriate condition. For example:
if (ntohl(e->msg.status) != BWFM_E_STATUS_SUCCESS) &&
ic->ic_state == IEEE80211_S_AUTH)
ieee80211_begin_scan(ifp);
> break;
> case BWFM_E_ASSOC:
> - if (ntohl(e->msg.status) == BWFM_E_STATUS_SUCCESS &&
> - ic->ic_state == IEEE80211_S_ASSOC)
> - ieee80211_new_state(ic, IEEE80211_S_RUN, -1);
> - else if (ntohl(e->msg.status) != BWFM_E_STATUS_UNSOLICITED)
> - ieee80211_begin_scan(ifp);
> + ieee80211_begin_scan(ifp);
Same here:
if (ntohl(e->msg.status) != BWFM_E_STATUS_SUCCESS) &&
ic->ic_state == IEEE80211_S_ASSOC)
ieee80211_begin_scan(ifp);
> break;
> case BWFM_E_DEAUTH:
> case BWFM_E_DISASSOC:
> @@ -2650,9 +2674,6 @@ bwfm_rx_event_cb(struct bwfm_softc *sc,
> ieee80211_begin_scan(ifp);
> break;
> case BWFM_E_LINK:
> - if (ntohl(e->msg.status) == BWFM_E_STATUS_SUCCESS &&
> - ntohl(e->msg.reason) == 0)
> - break;
> /* Link status has changed */
> if (ic->ic_state > IEEE80211_S_SCAN)
> ieee80211_begin_scan(ifp);
bwfm fixes