[net80211] Begin implementing rate control module stats.

* Implement a new ratectl method, which defaults to returning nothing;
* Add a top level sysctl (net.wlan.X.rate_stats) to extract it;
* Add ratectl info for the 'amrr' module.

Tested:

* urtwn(4), STA mode

Differential Revision:	https://reviews.freebsd.org/D5630

sys/net80211/ieee80211_amrr.c

@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/module.h>
+#include <sys/sbuf.h>
 #include <sys/socket.h>
 #include <sys/sysctl.h>
 
@@ -75,6 +76,7 @@ static void	amrr_tx_update(const struct ieee80211vap *vap,
 			const struct ieee80211_node *, void *, void *, void *);
 static void	amrr_sysctlattach(struct ieee80211vap *,
 			struct sysctl_ctx_list *, struct sysctl_oid *);
+static void	amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s);
 
 /* number of references from net80211 layer */
 static	int nrefs = 0;
@@ -91,6 +93,7 @@ static const struct ieee80211_ratectl amrr = {
 	.ir_tx_complete	= amrr_tx_complete,
 	.ir_tx_update	= amrr_tx_update,
 	.ir_setinterval	= amrr_setinterval,
+	.ir_node_stats	= amrr_node_stats,
 };
 IEEE80211_RATECTL_MODULE(amrr, 1);
 IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
@@ -410,3 +413,31 @@ amrr_sysctlattach(struct ieee80211vap *vap,
 	    "amrr_min_sucess_threshold", CTLFLAG_RW,
 	    &amrr->amrr_min_success_threshold, 0, "");
 }
+
+static void
+amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s)
+{
+	int rate;
+	struct ieee80211_amrr_node *amn = ni->ni_rctls;
+	struct ieee80211_rateset *rs;
+
+	/* XXX TODO: check locking? */
+
+	/* XXX TODO: this should be a method */
+	if (amrr_node_is_11n(ni)) {
+		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
+		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
+		sbuf_printf(s, "rate: MCS %d\n", rate);
+	} else {
+		rs = &ni->ni_rates;
+		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
+		sbuf_printf(s, "rate: %d Mbit\n", rate / 2);
+	}
+
+	sbuf_printf(s, "ticks: %d\n", amn->amn_ticks);
+	sbuf_printf(s, "txcnt: %u\n", amn->amn_txcnt);
+	sbuf_printf(s, "success: %u\n", amn->amn_success);
+	sbuf_printf(s, "success_threshold: %u\n", amn->amn_success_threshold);
+	sbuf_printf(s, "recovery: %u\n", amn->amn_recovery);
+	sbuf_printf(s, "retry_cnt: %u\n", amn->amn_retrycnt);
+}

sys/net80211/ieee80211_ratectl.c

@@ -28,6 +28,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
+#include <sys/sbuf.h>
 #include <sys/systm.h>
 #include <sys/socket.h>
 #include <sys/malloc.h>
@@ -68,12 +69,52 @@ ieee80211_ratectl_unregister(int type)
 	ratectls[type] = NULL;
 }
 
+static void
+ieee80211_ratectl_sysctl_stats_node_iter(void *arg, struct ieee80211_node *ni)
+{
+
+	struct sbuf *sb = (struct sbuf *) arg;
+	sbuf_printf(sb, "MAC: %6D\n", ni->ni_macaddr, ":");
+	ieee80211_ratectl_node_stats(ni, sb);
+	sbuf_printf(sb, "\n");
+}
+
+static int
+ieee80211_ratectl_sysctl_stats(SYSCTL_HANDLER_ARGS)
+{
+	struct ieee80211vap *vap = arg1;
+	struct ieee80211com *ic = vap->iv_ic;
+	struct sbuf sb;
+	int error;
+
+	error = sysctl_wire_old_buffer(req, 0);
+	if (error)
+		return (error);
+	sbuf_new_for_sysctl(&sb, NULL, 8, req);
+	sbuf_clear_flags(&sb, SBUF_INCLUDENUL);
+
+	IEEE80211_LOCK(ic);
+	ieee80211_iterate_nodes(&ic->ic_sta,
+	    ieee80211_ratectl_sysctl_stats_node_iter,
+	    &sb);
+	IEEE80211_UNLOCK(ic);
+
+	error = sbuf_finish(&sb);
+	sbuf_delete(&sb);
+	return (error);
+}
+
 void
 ieee80211_ratectl_init(struct ieee80211vap *vap)
 {
 	if (vap->iv_rate == ratectls[IEEE80211_RATECTL_NONE])
 		ieee80211_ratectl_set(vap, IEEE80211_RATECTL_AMRR);
 	vap->iv_rate->ir_init(vap);
+
+	/* Attach generic stats sysctl */
+	SYSCTL_ADD_PROC(vap->iv_sysctl, SYSCTL_CHILDREN(vap->iv_oid), OID_AUTO,
+	    "rate_stats", CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, vap,
+	    0, ieee80211_ratectl_sysctl_stats, "A", "ratectl node stats");
 }
 
 void

sys/net80211/ieee80211_ratectl.h

@@ -53,6 +53,7 @@ struct ieee80211_ratectl {
 	    			const struct ieee80211_node *,
 	    			void *, void *, void *);
 	void	(*ir_setinterval)(const struct ieee80211vap *, int);
+	void	(*ir_node_stats)(struct ieee80211_node *ni, struct sbuf *s);
 };
 
 void	ieee80211_ratectl_register(int, const struct ieee80211_ratectl *);
@@ -115,3 +116,13 @@ ieee80211_ratectl_setinterval(const struct ieee80211vap *vap, int msecs)
 		return;
 	vap->iv_rate->ir_setinterval(vap, msecs);
 }
+
+static __inline void
+ieee80211_ratectl_node_stats(struct ieee80211_node *ni, struct sbuf *s)
+{
+	const struct ieee80211vap *vap = ni->ni_vap;
+
+	if (vap->iv_rate->ir_node_stats == NULL)
+		return;
+	vap->iv_rate->ir_node_stats(ni, s);
+}