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>

1 files changed, 19 insertions, 0 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 17258feaab9b..d3b408cda08d 100644
--- 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;