s/w beacon miss facility; need to add knobs to fiddle with the settings

MFC after:	2 weeks

sys/net80211/ieee80211_input.c

@@ -1901,6 +1901,9 @@ ieee80211_recv_mgmt(struct ieee80211com *ic, struct mbuf *m0,
 			/* record tsf of last beacon */
 			memcpy(ni->ni_tstamp.data, scan.tstamp,
 				sizeof(ni->ni_tstamp));
+			/* count beacon frame for s/w bmiss handling */
+			ic->ic_swbmiss_count++;
+			ic->ic_bmiss_count = 0;
 			if (ni->ni_erp != scan.erp) {
 				IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
 				    "[%s] erp change: was 0x%x, now 0x%x\n",
@@ -1944,7 +1947,6 @@ ieee80211_recv_mgmt(struct ieee80211com *ic, struct mbuf *m0,
 			if (ic->ic_flags & IEEE80211_F_SCAN)
 				ieee80211_add_scan(ic, &scan, wh,
 					subtype, rssi, rstamp);
-			ic->ic_bmiss_count = 0;
 			return;
 		}
 		/*

sys/net80211/ieee80211_proto.c

@@ -98,6 +98,7 @@ ieee80211_proto_attach(struct ieee80211com *ic)
 	ic->ic_fragthreshold = IEEE80211_FRAG_DEFAULT;
 	ic->ic_fixed_rate = IEEE80211_FIXED_RATE_NONE;
 	ic->ic_bmiss_max = IEEE80211_BMISS_MAX;
+	callout_init(&ic->ic_swbmiss, CALLOUT_MPSAFE);
 	ic->ic_mcast_rate = IEEE80211_MCAST_RATE_DEFAULT;
 	ic->ic_protmode = IEEE80211_PROT_CTSONLY;
 	ic->ic_roaming = IEEE80211_ROAMING_AUTO;
@@ -855,6 +856,26 @@ ieee80211_beacon_miss(struct ieee80211com *ic)
 	ieee80211_new_state(ic, IEEE80211_S_SCAN, 0);
 }
 
+/*
+ * Software beacon miss handling.  Check if any beacons
+ * were received in the last period.  If not post a
+ * beacon miss; otherwise reset the counter.
+ */
+static void
+ieee80211_swbmiss(void *arg)
+{
+	struct ieee80211com *ic = arg;
+
+	if (ic->ic_swbmiss_count == 0) {
+		ieee80211_beacon_miss(ic);
+		if (ic->ic_bmiss_count == 0)	/* don't re-arm timer */
+			return;
+	} else
+		ic->ic_swbmiss_count = 0;
+	callout_reset(&ic->ic_swbmiss, ic->ic_swbmiss_period,
+		ieee80211_swbmiss, ic);
+}
+
 static void
 sta_disassoc(void *arg, struct ieee80211_node *ni)
 {
@@ -888,6 +909,8 @@ ieee80211_newstate(struct ieee80211com *ic, enum ieee80211_state nstate, int arg
 		ieee80211_state_name[ostate], ieee80211_state_name[nstate]);
 	ic->ic_state = nstate;			/* state transition */
 	ni = ic->ic_bss;			/* NB: no reference held */
+	if (ic->ic_flags_ext & IEEE80211_FEXT_SWBMISS)
+		callout_stop(&ic->ic_swbmiss);
 	switch (nstate) {
 	case IEEE80211_S_INIT:
 		switch (ostate) {
@@ -1093,6 +1116,20 @@ ieee80211_newstate(struct ieee80211com *ic, enum ieee80211_state nstate, int arg
 			if_start(ifp);		/* XXX not authorized yet */
 			break;
 		}
+		if (ostate != IEEE80211_S_RUN &&
+		    ic->ic_opmode == IEEE80211_M_STA &&
+		    (ic->ic_flags_ext & IEEE80211_FEXT_SWBMISS)) {
+			/*
+			 * Start s/w beacon miss timer for devices w/o
+			 * hardware support.  We fudge a bit here since
+			 * we're doing this in software.
+			 */
+			ic->ic_swbmiss_period = IEEE80211_TU_TO_TICKS(
+				2 * ic->ic_bmissthreshold * ni->ni_intval);
+			ic->ic_swbmiss_count = 0;
+			callout_reset(&ic->ic_swbmiss, ic->ic_swbmiss_period,
+				ieee80211_swbmiss, ic);
+		}
 		/*
 		 * Start/stop the authenticator when operating as an
 		 * AP.  We delay until here to allow configuration to

sys/net80211/ieee80211_var.h

@@ -71,6 +71,7 @@
 #define	IEEE80211_BINTVAL_DEFAULT 100	/* default beacon interval (TU's) */
 
 #define	IEEE80211_BMISS_MAX	2	/* maximum consecutive bmiss allowed */
+#define	IEEE80211_SWBMISS_THRESHOLD 50	/* s/w bmiss threshold (TU's) */
 
 #define	IEEE80211_PS_SLEEP	0x1	/* STA is in power saving mode */
 #define	IEEE80211_PS_MAX_QUEUE	50	/* maximum saved packets */
@@ -83,6 +84,7 @@
 
 #define	IEEE80211_MS_TO_TU(x)	(((x) * 1024) / 1000)
 #define	IEEE80211_TU_TO_MS(x)	(((x) * 1000) / 1024)
+#define	IEEE80211_TU_TO_TICKS(x)(((x) * hz) / 1024)
 
 struct ieee80211_aclator;
 struct sysctl_ctx_list;
@@ -147,6 +149,9 @@ struct ieee80211com {
 	u_int8_t		ic_bmissthreshold;
 	u_int8_t		ic_bmiss_count;	/* current beacon miss count */
 	int			ic_bmiss_max;	/* max bmiss before scan */
+	u_int16_t		ic_swbmiss_count;/* beacons in last period */
+	u_int16_t		ic_swbmiss_period;/* s/w bmiss period */
+	struct callout		ic_swbmiss;	/* s/w beacon miss timer */
 	struct ieee80211_node	*(*ic_node_alloc)(struct ieee80211_node_table*);
 	void			(*ic_node_free)(struct ieee80211_node *);
 	void			(*ic_node_cleanup)(struct ieee80211_node *);
@@ -247,6 +252,7 @@ struct ieee80211com {
 /* 0x00000006 reserved */
 #define	IEEE80211_FEXT_BGSCAN	0x00000008	/* STATUS: enable full bgscan completion */
 #define	IEEE80211_FEXT_ERPUPDATE 0x00000200	/* STATUS: update ERP element */
+#define	IEEE80211_FEXT_SWBMISS	0x00000400	/* CONF: do bmiss in s/w */
 
 /* ic_caps */
 #define	IEEE80211_C_WEP		0x00000001	/* CAPABILITY: WEP available */