Introduce ieee80211_min_basic_rate() and ieee80211_max_basic_rate().

These helpers can be used by drivers to improve compatibility with APs
that disable some mandatory PHY rates in the basic rate set.

For instance, many of our drivers hard-code 11b rates on 2 Ghz and run
into problems when APs disable them. Since 11b rates are being disabled
by default by some vendors, hardcoding them is not a good idea anymore.

ok mpi@ phessler@

diff --git a/sys/net80211/ieee80211.c b/sys/net80211/ieee80211.c
index e330f8e..a5da6f1 100644 (file)
--- a/sys/net80211/ieee80211.c
+++ b/sys/net80211/ieee80211.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ieee80211.c,v 1.58 2016/01/13 14:33:07 stsp Exp $     */
+/*     $OpenBSD: ieee80211.c,v 1.59 2017/05/30 11:00:38 stsp Exp $     */
 /*     $NetBSD: ieee80211.c,v 1.19 2004/06/06 05:45:29 dyoung Exp $    */
 
 /*-
@@ -712,6 +712,43 @@ ieee80211_setbasicrates(struct ieee80211com *ic)
        }
 }
 
+int
+ieee80211_min_basic_rate(struct ieee80211com *ic)
+{
+       struct ieee80211_rateset *rs = &ic->ic_bss->ni_rates;
+       int i;
+
+       for (i = 0; i < rs->rs_nrates; i++) {
+               if (rs->rs_rates[i] & IEEE80211_RATE_BASIC)
+                       return i;
+       }
+
+       return 0;
+}
+
+int
+ieee80211_max_basic_rate(struct ieee80211com *ic)
+{
+       struct ieee80211_rateset *rs = &ic->ic_bss->ni_rates;
+       int i, best, rval, best_rval;
+
+       /* Defaults to 1 Mbit/s on 2GHz and 6 Mbit/s on 5GHz. */
+       best = 0;
+       best_rval = (rs->rs_rates[best] & IEEE80211_RATE_VAL);
+
+       for (i = 0; i < rs->rs_nrates; i++) {
+               if ((rs->rs_rates[i] & IEEE80211_RATE_BASIC) == 0)
+                       continue;
+               rval = (rs->rs_rates[i] & IEEE80211_RATE_VAL);
+               if (rval > best_rval) {
+                       best_rval = rval;
+                       best = i;
+               }
+       }
+
+       return best;
+}
+
 /*
  * Set the current phy mode and recalculate the active channel
  * set based on the available channels for this mode.  Also

diff --git a/sys/net80211/ieee80211_var.h b/sys/net80211/ieee80211_var.h
index 627eaeb..7d6bb1b 100644 (file)
--- a/sys/net80211/ieee80211_var.h
+++ b/sys/net80211/ieee80211_var.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ieee80211_var.h,v 1.77 2017/02/02 16:47:53 stsp Exp $ */
+/*     $OpenBSD: ieee80211_var.h,v 1.78 2017/05/30 11:00:38 stsp Exp $ */
 /*     $NetBSD: ieee80211_var.h,v 1.7 2004/05/06 03:07:10 dyoung Exp $ */
 
 /*-
@@ -402,6 +402,8 @@ u_int       ieee80211_mhz2ieee(u_int, u_int);
 u_int  ieee80211_chan2ieee(struct ieee80211com *,
                const struct ieee80211_channel *);
 u_int  ieee80211_ieee2mhz(u_int, u_int);
+int    ieee80211_min_basic_rate(struct ieee80211com *);
+int    ieee80211_max_basic_rate(struct ieee80211com *);
 int    ieee80211_setmode(struct ieee80211com *, enum ieee80211_phymode);
 enum ieee80211_phymode ieee80211_next_mode(struct ifnet *);
 enum ieee80211_phymode ieee80211_chan2mode(struct ieee80211com *,