mac80211: use min rate as basic rate for buggy APs

Some buggy APs (and even P2P_GO) don't advertise their
basic rates in the association response.

In such case, use the min supported rate as the
basic rate.

Reported-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 17258feaab9b8f9c6958e64502a7587501dbfa8f..d3b408cda08dee3e0648bdd4ee4bc410a1c72896 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1485,6 +1485,7 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
        int i, j, err;
        bool have_higher_than_11mbit = false;
        u16 ap_ht_cap_flags;
+       int min_rate = INT_MAX, min_rate_index = -1;
 
        /* AssocResp and ReassocResp have identical structure */
 
@@ -1551,6 +1552,10 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
                                rates |= BIT(j);
                                if (is_basic)
                                        basic_rates |= BIT(j);
+                               if (rate < min_rate) {
+                                       min_rate = rate;
+                                       min_rate_index = j;
+                               }
                                break;
                        }
                }
@@ -1568,11 +1573,25 @@ static bool ieee80211_assoc_success(struct ieee80211_work *wk,
                                rates |= BIT(j);
                                if (is_basic)
                                        basic_rates |= BIT(j);
+                               if (rate < min_rate) {
+                                       min_rate = rate;
+                                       min_rate_index = j;
+                               }
                                break;
                        }
                }
        }
 
+       /*
+        * some buggy APs don't advertise basic_rates. use the lowest
+        * supported rate instead.
+        */
+       if (unlikely(!basic_rates) && min_rate_index >= 0) {
+               printk(KERN_DEBUG "%s: No basic rates in AssocResp. "
+                      "Using min supported rate instead.\n", sdata->name);
+               basic_rates = BIT(min_rate_index);
+       }
+
        sta->sta.supp_rates[wk->chan->band] = rates;
        sdata->vif.bss_conf.basic_rates = basic_rates;