mac80211: add radiotap flag to assure frames are not reordered

Add a new radiotap flag to indicate injected frames must not be
reordered relative to other frames that also have this flag set,
independent of priority field values in the transmitted frame.
Parse this radiotap flag and define and set a corresponding Tx
control flag. Note that this flag has recently been standardized
as part of an update to radiotap.

Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
Link: https://lore.kernel.org/r/20201104061823.197407-2-Mathy.Vanhoef@kuleuven.be
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/ieee80211_radiotap.h

@@ -118,6 +118,7 @@ enum ieee80211_radiotap_tx_flags {
 	IEEE80211_RADIOTAP_F_TX_RTS = 0x0004,
 	IEEE80211_RADIOTAP_F_TX_NOACK = 0x0008,
 	IEEE80211_RADIOTAP_F_TX_NOSEQNO = 0x0010,
+	IEEE80211_RADIOTAP_F_TX_ORDER = 0x0020,
 };
 
 /* for IEEE80211_RADIOTAP_MCS "have" flags */

include/net/mac80211.h

@@ -857,6 +857,9 @@ enum mac80211_tx_info_flags {
  *	it can be sent out.
  * @IEEE80211_TX_CTRL_NO_SEQNO: Do not overwrite the sequence number that
  *	has already been assigned to this frame.
+ * @IEEE80211_TX_CTRL_DONT_REORDER: This frame should not be reordered
+ *	relative to other frames that have this flag set, independent
+ *	of their QoS TID or other priority field values.
  *
  * These flags are used in tx_info->control.flags.
  */
@@ -869,6 +872,7 @@ enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP	= BIT(5),
 	IEEE80211_TX_INTCFL_NEED_TXPROCESSING	= BIT(6),
 	IEEE80211_TX_CTRL_NO_SEQNO		= BIT(7),
+	IEEE80211_TX_CTRL_DONT_REORDER		= BIT(8),
 };
 
 /*

net/mac80211/tx.c

@@ -2102,6 +2102,9 @@ bool ieee80211_parse_tx_radiotap(struct sk_buff *skb,
 				info->flags |= IEEE80211_TX_CTL_NO_ACK;
 			if (txflags & IEEE80211_RADIOTAP_F_TX_NOSEQNO)
 				info->control.flags |= IEEE80211_TX_CTRL_NO_SEQNO;
+			if (txflags & IEEE80211_RADIOTAP_F_TX_ORDER)
+				info->control.flags |=
+					IEEE80211_TX_CTRL_DONT_REORDER;
 			break;
 
 		case IEEE80211_RADIOTAP_RATE: