mac80211: do not wip out old supported rates

Use old supported rates, if AP do not provide supported rates
information element in a new managment frame.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 2b1f1f3d6a58..a9d40584e383 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -84,7 +84,7 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 {
         struct cfg80211_bss *cbss;
         struct ieee80211_bss *bss;
-        int clen;
+        int clen, srlen;
         s32 signal = 0;
 
         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
@@ -113,23 +113,24 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
                 bss->dtim_period = tim_ie->dtim_period;
         }
 
-        bss->supp_rates_len = 0;
+        /* replace old supported rates if we get new values */
+        srlen = 0;
         if (elems->supp_rates) {
-                clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
+                clen = IEEE80211_MAX_SUPP_RATES;
                 if (clen > elems->supp_rates_len)
                         clen = elems->supp_rates_len;
-                memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
-                       clen);
-                bss->supp_rates_len += clen;
+                memcpy(bss->supp_rates, elems->supp_rates, clen);
+                srlen += clen;
         }
         if (elems->ext_supp_rates) {
-                clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
+                clen = IEEE80211_MAX_SUPP_RATES - srlen;
                 if (clen > elems->ext_supp_rates_len)
                         clen = elems->ext_supp_rates_len;
-                memcpy(&bss->supp_rates[bss->supp_rates_len],
-                       elems->ext_supp_rates, clen);
-                bss->supp_rates_len += clen;
+                memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, clen);
+                srlen += clen;
         }
+        if (srlen)
+                bss->supp_rates_len = srlen;
 
         bss->wmm_used = elems->wmm_param || elems->wmm_info;
         bss->uapsd_supported = is_uapsd_supported(elems);