mac80211_hwsim: check ATTR_FREQ for wmediumd (netlink) packets

If a packet is received from netlink with the frequency value set it is
checked against the current radio's frequency and discarded if different.
The frequency is also checked against data2->tmp_chan to support the "hw"
off-channel/scan case.
Signed-off-by: Adam Welle <arwelle@cert.org>
[allow both simultaneously, add locking]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -2879,10 +2879,25 @@ static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
 
 	/* A frame is received from user space */
 	memset(&rx_status, 0, sizeof(rx_status));
-	/* TODO: Check ATTR_FREQ if it exists, and maybe throw away off-channel
-	 * packets?
-	 */
-	rx_status.freq = data2->channel->center_freq;
+	if (info->attrs[HWSIM_ATTR_FREQ]) {
+		/* throw away off-channel packets, but allow both the temporary
+		 * ("hw" scan/remain-on-channel) and regular channel, since the
+		 * internal datapath also allows this
+		 */
+		mutex_lock(&data2->mutex);
+		rx_status.freq = nla_get_u32(info->attrs[HWSIM_ATTR_FREQ]);
+
+		if (rx_status.freq != data2->channel->center_freq &&
+		    (!data2->tmp_chan ||
+		     rx_status.freq != data2->tmp_chan->center_freq)) {
+			mutex_unlock(&data2->mutex);
+			goto out;
+		}
+		mutex_unlock(&data2->mutex);
+	} else {
+		rx_status.freq = data2->channel->center_freq;
+	}
+
 	rx_status.band = data2->channel->band;
 	rx_status.rate_idx = nla_get_u32(info->attrs[HWSIM_ATTR_RX_RATE]);
 	rx_status.signal = nla_get_u32(info->attrs[HWSIM_ATTR_SIGNAL]);