156 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			156 lines
		
	
	
		
			4.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From: Sven Eckelmann <sven@narfation.org>
 | 
						|
Date: Tue, 26 Jan 2016 17:11:13 +0100
 | 
						|
Subject: [PATCH] mac80211: Parse legacy and HT rate in injected frames
 | 
						|
 | 
						|
Drivers/devices without their own rate control algorithm can get the
 | 
						|
information what rates they should use from either the radiotap header of
 | 
						|
injected frames or from the rate control algorithm. But the parsing of the
 | 
						|
legacy rate information from the radiotap header was removed in commit
 | 
						|
e6a9854b05c1 ("mac80211/drivers: rewrite the rate control API").
 | 
						|
 | 
						|
The removal of this feature heavily reduced the usefulness of frame
 | 
						|
injection when wanting to simulate specific transmission behavior. Having
 | 
						|
rate parsing together with MCS rates and retry support allows a fine
 | 
						|
grained selection of the tx behavior of injected frames for these kind of
 | 
						|
tests.
 | 
						|
 | 
						|
Signed-off-by: Sven Eckelmann <sven@narfation.org>
 | 
						|
Cc: Simon Wunderlich <sw@simonwunderlich.de>
 | 
						|
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
 | 
						|
---
 | 
						|
 | 
						|
--- a/include/net/mac80211.h
 | 
						|
+++ b/include/net/mac80211.h
 | 
						|
@@ -708,12 +708,14 @@ enum mac80211_tx_info_flags {
 | 
						|
  *	protocol frame (e.g. EAP)
 | 
						|
  * @IEEE80211_TX_CTRL_PS_RESPONSE: This frame is a response to a poll
 | 
						|
  *	frame (PS-Poll or uAPSD).
 | 
						|
+ * @IEEE80211_TX_CTRL_RATE_INJECT: This frame is injected with rate information
 | 
						|
  *
 | 
						|
  * These flags are used in tx_info->control.flags.
 | 
						|
  */
 | 
						|
 enum mac80211_tx_control_flags {
 | 
						|
 	IEEE80211_TX_CTRL_PORT_CTRL_PROTO	= BIT(0),
 | 
						|
 	IEEE80211_TX_CTRL_PS_RESPONSE		= BIT(1),
 | 
						|
+	IEEE80211_TX_CTRL_RATE_INJECT		= BIT(2),
 | 
						|
 };
 | 
						|
 
 | 
						|
 /*
 | 
						|
--- a/net/mac80211/tx.c
 | 
						|
+++ b/net/mac80211/tx.c
 | 
						|
@@ -710,6 +710,10 @@ ieee80211_tx_h_rate_ctrl(struct ieee8021
 | 
						|
 
 | 
						|
 	info->control.short_preamble = txrc.short_preamble;
 | 
						|
 
 | 
						|
+	/* don't ask rate control when rate already injected via radiotap */
 | 
						|
+	if (info->control.flags & IEEE80211_TX_CTRL_RATE_INJECT)
 | 
						|
+		return TX_CONTINUE;
 | 
						|
+
 | 
						|
 	if (tx->sta)
 | 
						|
 		assoc = test_sta_flag(tx->sta, WLAN_STA_ASSOC);
 | 
						|
 
 | 
						|
@@ -1665,15 +1669,24 @@ void ieee80211_xmit(struct ieee80211_sub
 | 
						|
 	ieee80211_tx(sdata, sta, skb, false);
 | 
						|
 }
 | 
						|
 
 | 
						|
-static bool ieee80211_parse_tx_radiotap(struct sk_buff *skb)
 | 
						|
+static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
 | 
						|
+					struct sk_buff *skb)
 | 
						|
 {
 | 
						|
 	struct ieee80211_radiotap_iterator iterator;
 | 
						|
 	struct ieee80211_radiotap_header *rthdr =
 | 
						|
 		(struct ieee80211_radiotap_header *) skb->data;
 | 
						|
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 | 
						|
+	struct ieee80211_supported_band *sband =
 | 
						|
+		local->hw.wiphy->bands[info->band];
 | 
						|
 	int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len,
 | 
						|
 						   NULL);
 | 
						|
 	u16 txflags;
 | 
						|
+	u16 rate = 0;
 | 
						|
+	bool rate_found = false;
 | 
						|
+	u8 rate_retries = 0;
 | 
						|
+	u16 rate_flags = 0;
 | 
						|
+	u8 mcs_known, mcs_flags;
 | 
						|
+	int i;
 | 
						|
 
 | 
						|
 	info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
 | 
						|
 		       IEEE80211_TX_CTL_DONTFRAG;
 | 
						|
@@ -1724,6 +1737,35 @@ static bool ieee80211_parse_tx_radiotap(
 | 
						|
 				info->flags |= IEEE80211_TX_CTL_NO_ACK;
 | 
						|
 			break;
 | 
						|
 
 | 
						|
+		case IEEE80211_RADIOTAP_RATE:
 | 
						|
+			rate = *iterator.this_arg;
 | 
						|
+			rate_flags = 0;
 | 
						|
+			rate_found = true;
 | 
						|
+			break;
 | 
						|
+
 | 
						|
+		case IEEE80211_RADIOTAP_DATA_RETRIES:
 | 
						|
+			rate_retries = *iterator.this_arg;
 | 
						|
+			break;
 | 
						|
+
 | 
						|
+		case IEEE80211_RADIOTAP_MCS:
 | 
						|
+			mcs_known = iterator.this_arg[0];
 | 
						|
+			mcs_flags = iterator.this_arg[1];
 | 
						|
+			if (!(mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_MCS))
 | 
						|
+				break;
 | 
						|
+
 | 
						|
+			rate_found = true;
 | 
						|
+			rate = iterator.this_arg[2];
 | 
						|
+			rate_flags = IEEE80211_TX_RC_MCS;
 | 
						|
+
 | 
						|
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_GI &&
 | 
						|
+			    mcs_flags & IEEE80211_RADIOTAP_MCS_SGI)
 | 
						|
+				rate_flags |= IEEE80211_TX_RC_SHORT_GI;
 | 
						|
+
 | 
						|
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_BW &&
 | 
						|
+			    mcs_flags & IEEE80211_RADIOTAP_MCS_BW_40)
 | 
						|
+				rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
 | 
						|
+			break;
 | 
						|
+
 | 
						|
 		/*
 | 
						|
 		 * Please update the file
 | 
						|
 		 * Documentation/networking/mac80211-injection.txt
 | 
						|
@@ -1738,6 +1780,32 @@ static bool ieee80211_parse_tx_radiotap(
 | 
						|
 	if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
 | 
						|
 		return false;
 | 
						|
 
 | 
						|
+	if (rate_found) {
 | 
						|
+		info->control.flags |= IEEE80211_TX_CTRL_RATE_INJECT;
 | 
						|
+
 | 
						|
+		for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 | 
						|
+			info->control.rates[i].idx = -1;
 | 
						|
+			info->control.rates[i].flags = 0;
 | 
						|
+			info->control.rates[i].count = 0;
 | 
						|
+		}
 | 
						|
+
 | 
						|
+		if (rate_flags & IEEE80211_TX_RC_MCS) {
 | 
						|
+			info->control.rates[0].idx = rate;
 | 
						|
+		} else {
 | 
						|
+			for (i = 0; i < sband->n_bitrates; i++) {
 | 
						|
+				if (rate * 5 != sband->bitrates[i].bitrate)
 | 
						|
+					continue;
 | 
						|
+
 | 
						|
+				info->control.rates[0].idx = i;
 | 
						|
+				break;
 | 
						|
+			}
 | 
						|
+		}
 | 
						|
+
 | 
						|
+		info->control.rates[0].flags = rate_flags;
 | 
						|
+		info->control.rates[0].count = min_t(u8, rate_retries + 1,
 | 
						|
+						     local->hw.max_rate_tries);
 | 
						|
+	}
 | 
						|
+
 | 
						|
 	/*
 | 
						|
 	 * remove the radiotap header
 | 
						|
 	 * iterator->_max_length was sanity-checked against
 | 
						|
@@ -1819,7 +1887,7 @@ netdev_tx_t ieee80211_monitor_start_xmit
 | 
						|
 		      IEEE80211_TX_CTL_INJECTED;
 | 
						|
 
 | 
						|
 	/* process and remove the injection radiotap header */
 | 
						|
-	if (!ieee80211_parse_tx_radiotap(skb))
 | 
						|
+	if (!ieee80211_parse_tx_radiotap(local, skb))
 | 
						|
 		goto fail;
 | 
						|
 
 | 
						|
 	rcu_read_lock();
 |