mac80211: restrict advertised HW scan rates

Advertise only user-requested bitrates in a HW scan.
Note that the hw_scan API doesn't currently have a
way of asking for a specific probe request bitrate,
so we might end up using a bitrate that we don't
advertise as supported. I'll fix that later.

Also add a hexdump printk to hwsim to verify this.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -1130,6 +1130,8 @@ static int mac80211_hwsim_hw_scan(struct ieee80211_hw *hw,
 	for (i = 0; i < req->n_channels; i++)
 		printk(KERN_DEBUG "hwsim hw_scan freq %d\n",
 			req->channels[i]->center_freq);
+	print_hex_dump(KERN_DEBUG, "scan IEs: ", DUMP_PREFIX_OFFSET,
+			16, 1, req->ie, req->ie_len, 1);
 
 	ieee80211_queue_delayed_work(hw, &hsd->w, 2 * HZ);
 

net/mac80211/scan.c

@@ -228,6 +228,7 @@ ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 {
 	struct cfg80211_scan_request *req = local->scan_req;
+	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
 	enum ieee80211_band band;
 	int i, ielen, n_chans;
 
@@ -251,8 +252,8 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
 	local->hw_scan_req->n_channels = n_chans;
 
 	ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie,
-					 req->ie, req->ie_len, band, (u32) -1,
-					 0);
+					 req->ie, req->ie_len, band,
+					 sdata->rc_rateidx_mask[band], 0);
 	local->hw_scan_req->ie_len = ielen;
 
 	return true;