rt2x00: fix monitor mode regression

Since commit df1404650ccb ("mac80211: remove support for IFF_PROMISC")
monitor mode for rt2x00 has been made effectively useless because the
hardware filter is configured to drop packets whose intended recipient is
not the device, regardless of the presence of monitor mode interfaces.

This patch fixes this regression by adding explicit monitor mode support,
and by configuring the hardware filter accordingly.

Signed-off-by: Eli Cooper <elicooper@gmx.com>
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ralink/rt2x00/rt2400pci.c

@@ -273,8 +273,10 @@ static void rt2400pci_config_filter(struct rt2x00_dev *rt2x00dev,
 			   !(filter_flags & FIF_PLCPFAIL));
 	rt2x00_set_field32(&reg, RXCSR0_DROP_CONTROL,
 			   !(filter_flags & FIF_CONTROL));
-	rt2x00_set_field32(&reg, RXCSR0_DROP_NOT_TO_ME, 1);
+	rt2x00_set_field32(&reg, RXCSR0_DROP_NOT_TO_ME,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags));
 	rt2x00_set_field32(&reg, RXCSR0_DROP_TODS,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags) &&
 			   !rt2x00dev->intf_ap_count);
 	rt2x00_set_field32(&reg, RXCSR0_DROP_VERSION_ERROR, 1);
 	rt2x00mmio_register_write(rt2x00dev, RXCSR0, reg);

drivers/net/wireless/ralink/rt2x00/rt2500pci.c

@@ -274,8 +274,10 @@ static void rt2500pci_config_filter(struct rt2x00_dev *rt2x00dev,
 			   !(filter_flags & FIF_PLCPFAIL));
 	rt2x00_set_field32(&reg, RXCSR0_DROP_CONTROL,
 			   !(filter_flags & FIF_CONTROL));
-	rt2x00_set_field32(&reg, RXCSR0_DROP_NOT_TO_ME, 1);
+	rt2x00_set_field32(&reg, RXCSR0_DROP_NOT_TO_ME,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags));
 	rt2x00_set_field32(&reg, RXCSR0_DROP_TODS,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags) &&
 			   !rt2x00dev->intf_ap_count);
 	rt2x00_set_field32(&reg, RXCSR0_DROP_VERSION_ERROR, 1);
 	rt2x00_set_field32(&reg, RXCSR0_DROP_MCAST,

drivers/net/wireless/ralink/rt2x00/rt2500usb.c

@@ -437,8 +437,10 @@ static void rt2500usb_config_filter(struct rt2x00_dev *rt2x00dev,
 			   !(filter_flags & FIF_PLCPFAIL));
 	rt2x00_set_field16(&reg, TXRX_CSR2_DROP_CONTROL,
 			   !(filter_flags & FIF_CONTROL));
-	rt2x00_set_field16(&reg, TXRX_CSR2_DROP_NOT_TO_ME, 1);
+	rt2x00_set_field16(&reg, TXRX_CSR2_DROP_NOT_TO_ME,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags));
 	rt2x00_set_field16(&reg, TXRX_CSR2_DROP_TODS,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags) &&
 			   !rt2x00dev->intf_ap_count);
 	rt2x00_set_field16(&reg, TXRX_CSR2_DROP_VERSION_ERROR, 1);
 	rt2x00_set_field16(&reg, TXRX_CSR2_DROP_MULTICAST,

drivers/net/wireless/ralink/rt2x00/rt2800lib.c

@@ -1490,7 +1490,8 @@ void rt2800_config_filter(struct rt2x00_dev *rt2x00dev,
 			   !(filter_flags & FIF_FCSFAIL));
 	rt2x00_set_field32(&reg, RX_FILTER_CFG_DROP_PHY_ERROR,
 			   !(filter_flags & FIF_PLCPFAIL));
-	rt2x00_set_field32(&reg, RX_FILTER_CFG_DROP_NOT_TO_ME, 1);
+	rt2x00_set_field32(&reg, RX_FILTER_CFG_DROP_NOT_TO_ME,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags));
 	rt2x00_set_field32(&reg, RX_FILTER_CFG_DROP_NOT_MY_BSSD, 0);
 	rt2x00_set_field32(&reg, RX_FILTER_CFG_DROP_VER_ERROR, 1);
 	rt2x00_set_field32(&reg, RX_FILTER_CFG_DROP_MULTICAST,

drivers/net/wireless/ralink/rt2x00/rt2x00.h

@@ -669,6 +669,7 @@ enum rt2x00_state_flags {
 	CONFIG_POWERSAVING,
 	CONFIG_HT_DISABLED,
 	CONFIG_QOS_DISABLED,
+	CONFIG_MONITORING,
 
 	/*
 	 * Mark we currently are sequentially reading TX_STA_FIFO register

drivers/net/wireless/ralink/rt2x00/rt2x00config.c

@@ -277,6 +277,11 @@ void rt2x00lib_config(struct rt2x00_dev *rt2x00dev,
 	else
 		clear_bit(CONFIG_POWERSAVING, &rt2x00dev->flags);
 
+	if (conf->flags & IEEE80211_CONF_MONITOR)
+		set_bit(CONFIG_MONITORING, &rt2x00dev->flags);
+	else
+		clear_bit(CONFIG_MONITORING, &rt2x00dev->flags);
+
 	rt2x00dev->curr_band = conf->chandef.chan->band;
 	rt2x00dev->curr_freq = conf->chandef.chan->center_freq;
 	rt2x00dev->tx_power = conf->power_level;

drivers/net/wireless/ralink/rt2x00/rt2x00mac.c

@@ -385,11 +385,6 @@ void rt2x00mac_configure_filter(struct ieee80211_hw *hw,
 			*total_flags |= FIF_PSPOLL;
 	}
 
-	/*
-	 * Check if there is any work left for us.
-	 */
-	if (rt2x00dev->packet_filter == *total_flags)
-		return;
 	rt2x00dev->packet_filter = *total_flags;
 
 	rt2x00dev->ops->lib->config_filter(rt2x00dev, *total_flags);

drivers/net/wireless/ralink/rt2x00/rt61pci.c

@@ -530,8 +530,10 @@ static void rt61pci_config_filter(struct rt2x00_dev *rt2x00dev,
 			   !(filter_flags & FIF_PLCPFAIL));
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_CONTROL,
 			   !(filter_flags & (FIF_CONTROL | FIF_PSPOLL)));
-	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_NOT_TO_ME, 1);
+	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_NOT_TO_ME,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags));
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_TO_DS,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags) &&
 			   !rt2x00dev->intf_ap_count);
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_VERSION_ERROR, 1);
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_MULTICAST,

drivers/net/wireless/ralink/rt2x00/rt73usb.c

@@ -480,8 +480,10 @@ static void rt73usb_config_filter(struct rt2x00_dev *rt2x00dev,
 			   !(filter_flags & FIF_PLCPFAIL));
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_CONTROL,
 			   !(filter_flags & (FIF_CONTROL | FIF_PSPOLL)));
-	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_NOT_TO_ME, 1);
+	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_NOT_TO_ME,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags));
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_TO_DS,
+			   !test_bit(CONFIG_MONITORING, &rt2x00dev->flags) &&
 			   !rt2x00dev->intf_ap_count);
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_VERSION_ERROR, 1);
 	rt2x00_set_field32(&reg, TXRX_CSR0_DROP_MULTICAST,