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A Prism firmware participating in an IBSS network will not send a

Browse Source 
LINK_STAT notification for every change of BSSID, so the firmware's
BSSID and the driver's BSSID will get out of sync. This has two
bad affects. First, because the 802.11 framework filters received
packets based on BSSID, many packets can be dropped before the
driver adopts the firmware's BSSID.  Second, ifconfig's tells a
misleading BSSID to the operator.

This problem is most apparent in networks where every station does
not hear every other. I reproduce these conditions in an office by
removing/replacing the antennas on my 802.11 cards.

As a solution, in IBSS mode, the driver will ask the firmware for
the BSSID every five seconds. Also, whenever the driver receives
a frame carrying a different BSSID than the driver's BSSID, then
the driver asks the firmware for the BSSID before handing the frame
to ieee80211_input.
This commit is contained in:
dyoung 2003-01-01 02:06:47 +00:00
parent 95fa2e148a
commit 18d05b8362
2 changed files with 63 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
sys/dev/ic/wi.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: wi.c,v 1.106 2002/12/27 08:29:46 dyoung Exp $ */
/* $NetBSD: wi.c,v 1.107 2003/01/01 02:06:47 dyoung Exp $ */
/*
* Copyright (c) 1997, 1998, 1999
@ -70,7 +70,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: wi.c,v 1.106 2002/12/27 08:29:46 dyoung Exp $");
__KERNEL_RCSID(0, "$NetBSD: wi.c,v 1.107 2003/01/01 02:06:47 dyoung Exp $");
#define WI_HERMES_AUTOINC_WAR /* Work around data write autoinc bug. */
#define WI_HERMES_STATS_WAR /* Work around stats counter bug. */
@ -549,6 +549,8 @@ wi_init(struct ifnet *ifp)
case IEEE80211_M_IBSS:
wi_write_val(sc, WI_RID_PORTTYPE, sc->sc_ibss_port);
ic->ic_flags |= IEEE80211_F_IBSSON;
sc->sc_syn_timer = 5;
ifp->if_timer = 1;
break;
case IEEE80211_M_AHDEMO:
wi_write_val(sc, WI_RID_PORTTYPE, WI_PORTTYPE_ADHOC);
@ -699,6 +701,8 @@ wi_stop(struct ifnet *ifp, int disable)
sc->sc_tx_timer = 0;
sc->sc_scan_timer = 0;
sc->sc_syn_timer = 0;
sc->sc_false_syns = 0;
sc->sc_naps = 0;
ifp->if_flags &= ~(IFF_OACTIVE | IFF_RUNNING);
ifp->if_timer = 0;
@ -880,6 +884,17 @@ wi_watchdog(struct ifnet *ifp)
ifp->if_timer = 1;
}
if (sc->sc_syn_timer) {
if (--sc->sc_syn_timer == 0) {
DPRINTF2(("%s: %d false syns\n",
sc->sc_dev.dv_xname, sc->sc_false_syns));
sc->sc_false_syns = 0;
ieee80211_new_state(ifp, IEEE80211_S_RUN, -1);
sc->sc_syn_timer = 5;
}
ifp->if_timer = 1;
}
/* TODO: rate control */
ieee80211_watchdog(ifp);
}
@ -1074,6 +1089,31 @@ wi_media_status(struct ifnet *ifp, struct ifmediareq *imr)
}
}
static void
wi_sync_bssid(struct wi_softc *sc, u_int8_t new_bssid[IEEE80211_ADDR_LEN])
{
struct ieee80211com *ic = &sc->sc_ic;
struct ieee80211_node *ni = &ic->ic_bss;
struct ifnet *ifp = &ic->ic_if;
if (IEEE80211_ADDR_EQ(new_bssid, ni->ni_bssid))
return;
DPRINTF(("%s: bssid %s -> ", sc->sc_dev.dv_xname,
ether_sprintf(ni->ni_bssid)));
DPRINTF(("%s ?\n", ether_sprintf(new_bssid)));
/* In promiscuous mode, the BSSID field is not a reliable
* indicator of the firmware's BSSID. Damp spurious
* change-of-BSSID indications.
*/
if ((ifp->if_flags & IFF_PROMISC) != 0 &&
sc->sc_false_syns >= WI_MAX_FALSE_SYNS)
return;
ieee80211_new_state(ifp, IEEE80211_S_RUN, -1);
}
static void
wi_rx_intr(struct wi_softc *sc)
{
@ -1083,6 +1123,7 @@ wi_rx_intr(struct wi_softc *sc)
struct mbuf *m;
struct ieee80211_frame *wh;
int fid, len, off, rssi;
u_int8_t dir;
u_int16_t status;
u_int32_t rstamp;
@ -1160,6 +1201,12 @@ wi_rx_intr(struct wi_softc *sc)
*/
wh->i_fc[1] &= ~IEEE80211_FC1_WEP;
}
/* synchronize driver's BSSID with firmware's BSSID */
dir = wh->i_fc[1] & IEEE80211_FC1_DIR_MASK;
if (ic->ic_opmode == IEEE80211_M_IBSS && dir == IEEE80211_FC1_DIR_NODS)
wi_sync_bssid(sc, wh->i_addr3);
ieee80211_input(ifp, m, rssi, rstamp);
}
@ -2064,6 +2111,7 @@ wi_newstate(void *arg, enum ieee80211_state nstate)
int i, buflen;
u_int16_t val;
struct wi_ssid ssid;
u_int8_t old_bssid[IEEE80211_ADDR_LEN];
enum ieee80211_state ostate;
#ifdef WI_DEBUG
static const char *stname[] =
@ -2083,12 +2131,18 @@ wi_newstate(void *arg, enum ieee80211_state nstate)
case IEEE80211_S_RUN:
sc->sc_flags &= ~WI_FLAGS_OUTRANGE;
buflen = IEEE80211_ADDR_LEN;
IEEE80211_ADDR_COPY(old_bssid, ni->ni_bssid);
wi_read_rid(sc, WI_RID_CURRENT_BSSID, ni->ni_bssid, &buflen);
IEEE80211_ADDR_COPY(ni->ni_macaddr, ni->ni_bssid);
buflen = sizeof(val);
wi_read_rid(sc, WI_RID_CURRENT_CHAN, &val, &buflen);
ni->ni_chan = le16toh(val);
if (IEEE80211_ADDR_EQ(old_bssid, ni->ni_bssid))
sc->sc_false_syns++;
else
sc->sc_false_syns = 0;
if (ic->ic_opmode == IEEE80211_M_HOSTAP) {
ni->ni_esslen = ic->ic_des_esslen;
memcpy(ni->ni_essid, ic->ic_des_essid, ni->ni_esslen);

8
sys/dev/ic/wivar.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: wivar.h,v 1.26 2002/12/27 07:54:36 dyoung Exp $ */
/* $NetBSD: wivar.h,v 1.27 2003/01/01 02:06:47 dyoung Exp $ */
/*
* Copyright (c) 1997, 1998, 1999
@ -86,16 +86,22 @@ struct wi_softc {
int sc_txcur;
int sc_tx_timer;
int sc_scan_timer;
int sc_syn_timer;
struct wi_counters sc_stats;
u_int16_t sc_ibss_port;
struct wi_apinfo sc_aps[MAXAPINFO];
int sc_naps;
int sc_false_syns;
};
#define sc_if sc_ic.ic_if
/* maximum consecutive false change-of-BSSID indications */
#define WI_MAX_FALSE_SYNS 10
#define WI_SCAN_INQWAIT 3 /* wait sec before inquire */
#define WI_SCAN_WAIT 5 /* maximum scan wait */