[pkg-wpa-devel] r1952 - in /wpa/tags/2.3-2.1/debian: ./ patches/

slh-guest at users.alioth.debian.org slh-guest at users.alioth.debian.org
Mon Nov 23 00:13:27 UTC 2015


Author: slh-guest
Date: Mon Nov 23 00:13:27 2015
New Revision: 1952

URL: http://svn.debian.org/wsvn/?sc=1&rev=1952
Log:
* Non-maintainer upload.
* Import four patches from upstream git (wpasupplicant_band_selection_*.patch),
  manually unfuzzed, to improve 2.4/5 GHz band selection. (Closes: #795722)

Added:
    wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_8b2b718d.patch
    wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_a1b790eb.patch
    wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_aa517ae2.patch
    wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_f0d0a5d2.patch
Modified:
    wpa/tags/2.3-2.1/debian/changelog
    wpa/tags/2.3-2.1/debian/patches/series

Modified: wpa/tags/2.3-2.1/debian/changelog
URL: http://svn.debian.org/wsvn/wpa/tags/2.3-2.1/debian/changelog?rev=1952&op=diff
==============================================================================
--- wpa/tags/2.3-2.1/debian/changelog	(original)
+++ wpa/tags/2.3-2.1/debian/changelog	Mon Nov 23 00:13:27 2015
@@ -1,3 +1,11 @@
+wpa (2.3-2.1) unstable; urgency=medium
+
+  * Non-maintainer upload.
+  * Import four patches from upstream git (wpasupplicant_band_selection_*.patch),
+    manually unfuzzed, to improve 2.4/5 GHz band selection. (Closes: #795722)
+
+ -- Steinar H. Gunderson <sesse at debian.org>  Sun, 30 Aug 2015 14:47:56 +0200
+
 wpa (2.3-2) unstable; urgency=high
 
   * remove Kel Modderman from Uploaders as per his request, many thanks for

Modified: wpa/tags/2.3-2.1/debian/patches/series
URL: http://svn.debian.org/wsvn/wpa/tags/2.3-2.1/debian/patches/series?rev=1952&op=diff
==============================================================================
--- wpa/tags/2.3-2.1/debian/patches/series	(original)
+++ wpa/tags/2.3-2.1/debian/patches/series	Mon Nov 23 00:13:27 2015
@@ -9,3 +9,7 @@
 hostapd_fix-hostapd-operation-without-hw_mode-driver-data.patch
 wpasupplicant_fix-systemd-unit-dependencies.patch
 wpasupplicant_P2P-Validate-SSID-element-length-before-copying-it-C.patch
+wpasupplicant_band_selection_f0d0a5d2.patch
+wpasupplicant_band_selection_a1b790eb.patch
+wpasupplicant_band_selection_8b2b718d.patch
+wpasupplicant_band_selection_aa517ae2.patch

Added: wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_8b2b718d.patch
URL: http://svn.debian.org/wsvn/wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_8b2b718d.patch?rev=1952&op=file
==============================================================================
--- wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_8b2b718d.patch	(added)
+++ wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_8b2b718d.patch	Mon Nov 23 00:13:27 2015
@@ -0,0 +1,25 @@
+commit 8b2b718da9884d66684befe99d1fbdd9abe5fb5e
+Author: Jouni Malinen <j at w1.fi>
+Date:   Sat Feb 28 16:35:07 2015 +0200
+
+    Fix minor issue in HT40 max rate determination
+    
+    Commit a1b790eb9d7514d1a6e0582a07f695a1564caa59 ('Select AP based on
+    estimated maximum throughput') had a copy-paste bug than ended up
+    leaving one of the max_ht40_rate() cases unreachable. (CID 106087)
+    
+    Signed-off-by: Jouni Malinen <j at w1.fi>
+
+Index: wpa-2.3/wpa_supplicant/scan.c
+===================================================================
+--- wpa-2.3.orig/wpa_supplicant/scan.c
++++ wpa-2.3/wpa_supplicant/scan.c
+@@ -1810,7 +1810,7 @@ static unsigned int max_ht40_rate(int sn
+ 		return 81000; /* HT40 MCS4 */
+ 	if (snr < 22)
+ 		return 108000; /* HT40 MCS5 */
+-	if (snr < 22)
++	if (snr < 24)
+ 		return 121500; /* HT40 MCS6 */
+ 	return 135000; /* HT40 MCS7 */
+ }

Added: wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_a1b790eb.patch
URL: http://svn.debian.org/wsvn/wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_a1b790eb.patch?rev=1952&op=file
==============================================================================
--- wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_a1b790eb.patch	(added)
+++ wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_a1b790eb.patch	Mon Nov 23 00:13:27 2015
@@ -0,0 +1,369 @@
+commit a1b790eb9d7514d1a6e0582a07f695a1564caa59
+Author: Jouni Malinen <j at w1.fi>
+Date:   Sat Feb 21 22:53:42 2015 +0200
+
+    Select AP based on estimated maximum throughput
+    
+    This modifies the BSS selection routines to calculate SNR and estimated
+    throughput for each scan result and then use the estimated throughput as
+    a criteria for sorting the results. This extends the earlier design by
+    taking into account higher throughput rates if both the AP and local
+    device supports HT20, HT40, or VHT80. In addition, the maximum rate is
+    restricted based on SNR.
+    
+    In practice, this gives significantly higher probability of selecting
+    HT/VHT APs when there are multiple BSSes in the same ESS and SNR is not
+    low enough to prevent higher MCS use.
+    
+    Signed-off-by: Jouni Malinen <j at w1.fi>
+
+Index: wpa-2.3/src/drivers/driver.h
+===================================================================
+--- wpa-2.3.orig/src/drivers/driver.h
++++ wpa-2.3/src/drivers/driver.h
+@@ -202,6 +202,9 @@ struct hostapd_hw_modes {
+  * @tsf: Timestamp
+  * @age: Age of the information in milliseconds (i.e., how many milliseconds
+  * ago the last Beacon or Probe Response frame was received)
++ * @est_throughput: Estimated throughput in kbps (this is calculated during
++ * scan result processing if left zero by the driver wrapper)
++ * @snr: Signal-to-noise ratio in dB (calculated during scan result processing)
+  * @ie_len: length of the following IE field in octets
+  * @beacon_ie_len: length of the following Beacon IE field in octets
+  *
+@@ -225,6 +228,8 @@ struct wpa_scan_res {
+ 	int level;
+ 	u64 tsf;
+ 	unsigned int age;
++	unsigned int est_throughput;
++	int snr;
+ 	size_t ie_len;
+ 	size_t beacon_ie_len;
+ 	/*
+Index: wpa-2.3/wpa_supplicant/scan.c
+===================================================================
+--- wpa-2.3.orig/wpa_supplicant/scan.c
++++ wpa-2.3/wpa_supplicant/scan.c
+@@ -1554,8 +1554,8 @@ static int wpa_scan_result_compar(const
+ 	struct wpa_scan_res **_wb = (void *) b;
+ 	struct wpa_scan_res *wa = *_wa;
+ 	struct wpa_scan_res *wb = *_wb;
+-	int wpa_a, wpa_b, maxrate_a, maxrate_b;
+-	int snr_a, snr_b;
++	int wpa_a, wpa_b;
++	int snr_a, snr_b, snr_a_full, snr_b_full;
+ 
+ 	/* WPA/WPA2 support preferred */
+ 	wpa_a = wpa_scan_get_vendor_ie(wa, WPA_IE_VENDOR_TYPE) != NULL ||
+@@ -1577,22 +1577,22 @@ static int wpa_scan_result_compar(const
+ 		return -1;
+ 
+ 	if (wa->flags & wb->flags & WPA_SCAN_LEVEL_DBM) {
+-		snr_a = MIN(wa->level - wa->noise, GREAT_SNR);
+-		snr_b = MIN(wb->level - wb->noise, GREAT_SNR);
++		snr_a_full = wa->snr;
++		snr_a = MIN(wa->snr, GREAT_SNR);
++		snr_b_full = wb->snr;
++		snr_b = MIN(wa->snr, GREAT_SNR);
+ 	} else {
+ 		/* Level is not in dBm, so we can't calculate
+ 		 * SNR. Just use raw level (units unknown). */
+-		snr_a = wa->level;
+-		snr_b = wb->level;
++		snr_a = snr_a_full = wa->level;
++		snr_b = snr_b_full = wb->level;
+ 	}
+ 
+ 	/* if SNR is close, decide by max rate or frequency band */
+ 	if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) ||
+ 	    (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
+-		maxrate_a = wpa_scan_get_max_rate(wa);
+-		maxrate_b = wpa_scan_get_max_rate(wb);
+-		if (maxrate_a != maxrate_b)
+-			return maxrate_b - maxrate_a;
++		if (wa->est_throughput != wb->est_throughput)
++			return wb->est_throughput - wa->est_throughput;
+ 		if (IS_5GHZ(wa->freq) ^ IS_5GHZ(wb->freq))
+ 			return IS_5GHZ(wa->freq) ? -1 : 1;
+ 	}
+@@ -1600,9 +1600,9 @@ static int wpa_scan_result_compar(const
+ 	/* all things being equal, use SNR; if SNRs are
+ 	 * identical, use quality values since some drivers may only report
+ 	 * that value and leave the signal level zero */
+-	if (snr_b == snr_a)
++	if (snr_b_full == snr_a_full)
+ 		return wb->qual - wa->qual;
+-	return snr_b - snr_a;
++	return snr_b_full - snr_a_full;
+ #undef MIN
+ }
+ 
+@@ -1669,20 +1669,21 @@ static void dump_scan_res(struct wpa_sca
+ 		struct wpa_scan_res *r = scan_res->res[i];
+ 		u8 *pos;
+ 		if (r->flags & WPA_SCAN_LEVEL_DBM) {
+-			int snr = r->level - r->noise;
+ 			int noise_valid = !(r->flags & WPA_SCAN_NOISE_INVALID);
+ 
+ 			wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
+-				   "noise=%d%s level=%d snr=%d%s flags=0x%x age=%u",
++				   "noise=%d%s level=%d snr=%d%s flags=0x%x age=%u est=%u",
+ 				   MAC2STR(r->bssid), r->freq, r->qual,
+ 				   r->noise, noise_valid ? "" : "~", r->level,
+-				   snr, snr >= GREAT_SNR ? "*" : "", r->flags,
+-				   r->age);
++				   r->snr, r->snr >= GREAT_SNR ? "*" : "",
++				   r->flags,
++				   r->age, r->est_throughput);
+ 		} else {
+ 			wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
+-				   "noise=%d level=%d flags=0x%x age=%u",
++				   "noise=%d level=%d flags=0x%x age=%u est=%u",
+ 				   MAC2STR(r->bssid), r->freq, r->qual,
+-				   r->noise, r->level, r->flags, r->age);
++				   r->noise, r->level, r->flags, r->age,
++				   r->est_throughput);
+ 		}
+ 		pos = (u8 *) (r + 1);
+ 		if (r->ie_len)
+@@ -1757,6 +1758,180 @@ static void filter_scan_res(struct wpa_s
+ #define DEFAULT_NOISE_FLOOR_2GHZ (-89)
+ #define DEFAULT_NOISE_FLOOR_5GHZ (-92)
+ 
++static void scan_snr(struct wpa_scan_res *res)
++{
++	if (res->flags & WPA_SCAN_NOISE_INVALID) {
++		res->noise = IS_5GHZ(res->freq) ?
++			DEFAULT_NOISE_FLOOR_5GHZ :
++			DEFAULT_NOISE_FLOOR_2GHZ;
++	}
++
++	if (res->flags & WPA_SCAN_LEVEL_DBM) {
++		res->snr = res->level - res->noise;
++	} else {
++		/* Level is not in dBm, so we can't calculate
++		 * SNR. Just use raw level (units unknown). */
++		res->snr = res->level;
++	}
++}
++
++
++static unsigned int max_ht20_rate(int snr)
++{
++	if (snr < 6)
++		return 6500; /* HT20 MCS0 */
++	if (snr < 8)
++		return 13000; /* HT20 MCS1 */
++	if (snr < 13)
++		return 19500; /* HT20 MCS2 */
++	if (snr < 17)
++		return 26000; /* HT20 MCS3 */
++	if (snr < 20)
++		return 39000; /* HT20 MCS4 */
++	if (snr < 23)
++		return 52000; /* HT20 MCS5 */
++	if (snr < 24)
++		return 58500; /* HT20 MCS6 */
++	return 65000; /* HT20 MCS7 */
++}
++
++
++static unsigned int max_ht40_rate(int snr)
++{
++	if (snr < 3)
++		return 13500; /* HT40 MCS0 */
++	if (snr < 6)
++		return 27000; /* HT40 MCS1 */
++	if (snr < 10)
++		return 40500; /* HT40 MCS2 */
++	if (snr < 15)
++		return 54000; /* HT40 MCS3 */
++	if (snr < 17)
++		return 81000; /* HT40 MCS4 */
++	if (snr < 22)
++		return 108000; /* HT40 MCS5 */
++	if (snr < 22)
++		return 121500; /* HT40 MCS6 */
++	return 135000; /* HT40 MCS7 */
++}
++
++
++static unsigned int max_vht80_rate(int snr)
++{
++	if (snr < 1)
++		return 0;
++	if (snr < 2)
++		return 29300; /* VHT80 MCS0 */
++	if (snr < 5)
++		return 58500; /* VHT80 MCS1 */
++	if (snr < 9)
++		return 87800; /* VHT80 MCS2 */
++	if (snr < 11)
++		return 117000; /* VHT80 MCS3 */
++	if (snr < 15)
++		return 175500; /* VHT80 MCS4 */
++	if (snr < 16)
++		return 234000; /* VHT80 MCS5 */
++	if (snr < 18)
++		return 263300; /* VHT80 MCS6 */
++	if (snr < 20)
++		return 292500; /* VHT80 MCS7 */
++	if (snr < 22)
++		return 351000; /* VHT80 MCS8 */
++	return 390000; /* VHT80 MCS9 */
++}
++
++
++static void scan_est_throughput(struct wpa_supplicant *wpa_s,
++				struct wpa_scan_res *res)
++{
++	enum local_hw_capab capab = wpa_s->hw_capab;
++	int rate; /* max legacy rate in 500 kb/s units */
++	const u8 *ie;
++	unsigned int est, tmp;
++	int snr = res->snr;
++
++	if (res->est_throughput)
++		return;
++
++	/* Get maximum legacy rate */
++	rate = wpa_scan_get_max_rate(res);
++
++	/* Limit based on estimated SNR */
++	if (rate > 1 * 2 && snr < 1)
++		rate = 1 * 2;
++	else if (rate > 2 * 2 && snr < 4)
++		rate = 2 * 2;
++	else if (rate > 6 * 2 && snr < 5)
++		rate = 6 * 2;
++	else if (rate > 9 * 2 && snr < 6)
++		rate = 9 * 2;
++	else if (rate > 12 * 2 && snr < 7)
++		rate = 12 * 2;
++	else if (rate > 18 * 2 && snr < 10)
++		rate = 18 * 2;
++	else if (rate > 24 * 2 && snr < 11)
++		rate = 24 * 2;
++	else if (rate > 36 * 2 && snr < 15)
++		rate = 36 * 2;
++	else if (rate > 48 * 2 && snr < 19)
++		rate = 48 * 2;
++	else if (rate > 54 * 2 && snr < 21)
++		rate = 54 * 2;
++	est = rate * 500;
++
++	if (capab == CAPAB_HT || capab == CAPAB_HT40 || capab == CAPAB_VHT) {
++		ie = wpa_scan_get_ie(res, WLAN_EID_HT_CAP);
++		if (ie) {
++			tmp = max_ht20_rate(snr);
++			if (tmp > est)
++				est = tmp;
++		}
++	}
++
++	if (capab == CAPAB_HT40 || capab == CAPAB_VHT) {
++		ie = wpa_scan_get_ie(res, WLAN_EID_HT_OPERATION);
++		if (ie && ie[1] >= 2 &&
++		    (ie[3] & HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK)) {
++			tmp = max_ht40_rate(snr);
++			if (tmp > est)
++				est = tmp;
++		}
++	}
++
++	if (capab == CAPAB_VHT) {
++		/* Use +1 to assume VHT is always faster than HT */
++		ie = wpa_scan_get_ie(res, WLAN_EID_VHT_CAP);
++		if (ie) {
++			tmp = max_ht20_rate(snr) + 1;
++			if (tmp > est)
++				est = tmp;
++
++			ie = wpa_scan_get_ie(res, WLAN_EID_HT_OPERATION);
++			if (ie && ie[1] >= 2 &&
++			    (ie[3] &
++			     HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK)) {
++				tmp = max_ht40_rate(snr) + 1;
++				if (tmp > est)
++					est = tmp;
++			}
++
++			ie = wpa_scan_get_ie(res, WLAN_EID_VHT_OPERATION);
++			if (ie && ie[1] >= 1 &&
++			    (ie[2] & VHT_OPMODE_CHANNEL_WIDTH_MASK)) {
++				tmp = max_vht80_rate(snr) + 1;
++				if (tmp > est)
++					est = tmp;
++			}
++		}
++	}
++
++	/* TODO: channel utilization and AP load (e.g., from AP Beacon) */
++
++	res->est_throughput = est;
++}
++
++
+ /**
+  * wpa_supplicant_get_scan_results - Get scan results
+  * @wpa_s: Pointer to wpa_supplicant data
+@@ -1793,12 +1968,8 @@ wpa_supplicant_get_scan_results(struct w
+ 	for (i = 0; i < scan_res->num; i++) {
+ 		struct wpa_scan_res *scan_res_item = scan_res->res[i];
+ 
+-		if (scan_res_item->flags & WPA_SCAN_NOISE_INVALID) {
+-			scan_res_item->noise =
+-				IS_5GHZ(scan_res_item->freq) ?
+-				DEFAULT_NOISE_FLOOR_5GHZ :
+-				DEFAULT_NOISE_FLOOR_2GHZ;
+-		}
++		scan_snr(scan_res_item);
++		scan_est_throughput(wpa_s, scan_res_item);
+ 	}
+ 
+ #ifdef CONFIG_WPS
+Index: wpa-2.3/wpa_supplicant/wpa_supplicant.c
+===================================================================
+--- wpa-2.3.orig/wpa_supplicant/wpa_supplicant.c
++++ wpa-2.3/wpa_supplicant/wpa_supplicant.c
+@@ -3759,6 +3759,23 @@ static int wpa_supplicant_init_iface(str
+ 	wpa_s->hw.modes = wpa_drv_get_hw_feature_data(wpa_s,
+ 						      &wpa_s->hw.num_modes,
+ 						      &wpa_s->hw.flags);
++	if (wpa_s->hw.modes) {
++		u16 i;
++
++		for (i = 0; i < wpa_s->hw.num_modes; i++) {
++			if (wpa_s->hw.modes[i].vht_capab) {
++				wpa_s->hw_capab = CAPAB_VHT;
++				break;
++			}
++
++			if (wpa_s->hw.modes[i].ht_capab &
++			    HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET)
++				wpa_s->hw_capab = CAPAB_HT40;
++			else if (wpa_s->hw.modes[i].ht_capab &&
++				 wpa_s->hw_capab == CAPAB_NO_HT_VHT)
++				wpa_s->hw_capab = CAPAB_HT;
++		}
++	}
+ 
+ 	if (wpa_drv_get_capa(wpa_s, &capa) == 0) {
+ 		wpa_s->drv_capa_known = 1;
+Index: wpa-2.3/wpa_supplicant/wpa_supplicant_i.h
+===================================================================
+--- wpa-2.3.orig/wpa_supplicant/wpa_supplicant_i.h
++++ wpa-2.3/wpa_supplicant/wpa_supplicant_i.h
+@@ -825,6 +825,12 @@ struct wpa_supplicant {
+ 		u16 num_modes;
+ 		u16 flags;
+ 	} hw;
++	enum local_hw_capab {
++		CAPAB_NO_HT_VHT,
++		CAPAB_HT,
++		CAPAB_HT40,
++		CAPAB_VHT,
++	} hw_capab;
+ #ifdef CONFIG_MACSEC
+ 	struct ieee802_1x_kay *kay;
+ #endif /* CONFIG_MACSEC */

Added: wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_aa517ae2.patch
URL: http://svn.debian.org/wsvn/wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_aa517ae2.patch?rev=1952&op=file
==============================================================================
--- wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_aa517ae2.patch	(added)
+++ wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_aa517ae2.patch	Mon Nov 23 00:13:27 2015
@@ -0,0 +1,26 @@
+commit aa517ae22784aff08d3d9e38ad101b4b5c9828fb
+Author: Hahn, Maital <maitalm at ti.com>
+Date:   Wed Jul 8 13:13:11 2015 +0000
+
+    wpa_supplicant: Fix a typo in wpa_scan_result_compar()
+    
+    A typo in wpa_scan_result_compar() caused wrong scan results sorting
+    (and wrong roaming decision). This fixes a copy-paste regression
+    introduced by commit a1b790eb9d7514d1a6e0582a07f695a1564caa59 ('Select
+    AP based on estimated maximum throughput').
+    
+    Signed-off-by: Maital Hahn <maitalm at ti.com>
+
+Index: wpa-2.3/wpa_supplicant/scan.c
+===================================================================
+--- wpa-2.3.orig/wpa_supplicant/scan.c
++++ wpa-2.3/wpa_supplicant/scan.c
+@@ -1580,7 +1580,7 @@ static int wpa_scan_result_compar(const
+ 		snr_a_full = wa->snr;
+ 		snr_a = MIN(wa->snr, GREAT_SNR);
+ 		snr_b_full = wb->snr;
+-		snr_b = MIN(wa->snr, GREAT_SNR);
++		snr_b = MIN(wb->snr, GREAT_SNR);
+ 	} else {
+ 		/* Level is not in dBm, so we can't calculate
+ 		 * SNR. Just use raw level (units unknown). */

Added: wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_f0d0a5d2.patch
URL: http://svn.debian.org/wsvn/wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_f0d0a5d2.patch?rev=1952&op=file
==============================================================================
--- wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_f0d0a5d2.patch	(added)
+++ wpa/tags/2.3-2.1/debian/patches/wpasupplicant_band_selection_f0d0a5d2.patch	Mon Nov 23 00:13:27 2015
@@ -0,0 +1,158 @@
+commit f0d0a5d23bd406a60358add9fa101b49dc9f9039
+Author: Mukesh Agrawal <quiche at chromium.org>
+Date:   Tue Apr 8 17:54:49 2014 -0700
+
+    Improve BSS selection with default noise floor values
+    
+    When noise floor measurements are not available, compute SNR
+    using default values for the noise floor. This helps steer us
+    towards 5 GHz BSSes in high signal strength environments.
+    
+    In more detail...
+    
+    Existing code prefers a 5 GHz BSS when the 5 GHz BSS's signal
+    strength is "close" to that of the 2.4 GHz BSS, or when both SNRs
+    are large. However, the mwifiex driver does not provide noise
+    floor measurements, so we can't compute SNRs.
+    
+    Because mwifiex doesn't provide NF measurements, the "large SNR"
+    code wasn't effective. By using default values for the noise floor,
+    we can again compute SNRs, and decide that the SNR is high enough
+    that we shouldn't worry about the exact difference in SNR.
+    
+    The default noise floor values (one for 2.4 GHz, and one for 5 GHz)
+    were chosen by measurement in a noisy environment, so they should be
+    conservative.
+    
+    Note that while this patch is motivated by mwifiex, it affects
+    ath9k as well. Although ath9k provides noise floor measurements
+    in general, it will sometimes fail to provide a measurement for
+    one or more specific channels.
+    
+    As a result of this patch, we'll always compare BSSes based on SNR
+    (either measured or estimated), rather than sometimes comparing
+    based on signal strength. ("Always" assumes that the
+    WPA_SCAN_LEVEL_DBM flag is set. It is for mwifiex and ath9k.)
+    
+    While there:
+    - fix a whitespace issue (spaces -> tab)
+    - clean up existing comments
+    - update dump_scan_res to indicate whether the noise floor is
+      measured, or default
+    
+    Signed-hostap: mukesh agrawal <quiche at chromium.org>
+
+Index: wpa-2.3/wpa_supplicant/scan.c
+===================================================================
+--- wpa-2.3.orig/wpa_supplicant/scan.c
++++ wpa-2.3/wpa_supplicant/scan.c
+@@ -1543,11 +1543,12 @@ struct wpabuf * wpa_scan_get_vendor_ie_m
+  */
+ #define GREAT_SNR 30
+ 
++#define IS_5GHZ(n) (n > 4000)
++
+ /* Compare function for sorting scan results. Return >0 if @b is considered
+  * better. */
+ static int wpa_scan_result_compar(const void *a, const void *b)
+ {
+-#define IS_5GHZ(n) (n > 4000)
+ #define MIN(a,b) a < b ? a : b
+ 	struct wpa_scan_res **_wa = (void *) a;
+ 	struct wpa_scan_res **_wb = (void *) b;
+@@ -1575,18 +1576,18 @@ static int wpa_scan_result_compar(const
+ 	    (wb->caps & IEEE80211_CAP_PRIVACY) == 0)
+ 		return -1;
+ 
+-	if ((wa->flags & wb->flags & WPA_SCAN_LEVEL_DBM) &&
+-	    !((wa->flags | wb->flags) & WPA_SCAN_NOISE_INVALID)) {
++	if (wa->flags & wb->flags & WPA_SCAN_LEVEL_DBM) {
+ 		snr_a = MIN(wa->level - wa->noise, GREAT_SNR);
+ 		snr_b = MIN(wb->level - wb->noise, GREAT_SNR);
+ 	} else {
+-		/* Not suitable information to calculate SNR, so use level */
++		/* Level is not in dBm, so we can't calculate
++		 * SNR. Just use raw level (units unknown). */
+ 		snr_a = wa->level;
+ 		snr_b = wb->level;
+ 	}
+ 
+-	/* best/max rate preferred if SNR close enough */
+-        if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) ||
++	/* if SNR is close, decide by max rate or frequency band */
++	if ((snr_a && snr_b && abs(snr_b - snr_a) < 5) ||
+ 	    (wa->qual && wb->qual && abs(wb->qual - wa->qual) < 10)) {
+ 		maxrate_a = wpa_scan_get_max_rate(wa);
+ 		maxrate_b = wpa_scan_get_max_rate(wb);
+@@ -1596,8 +1597,6 @@ static int wpa_scan_result_compar(const
+ 			return IS_5GHZ(wa->freq) ? -1 : 1;
+ 	}
+ 
+-	/* use freq for channel preference */
+-
+ 	/* all things being equal, use SNR; if SNRs are
+ 	 * identical, use quality values since some drivers may only report
+ 	 * that value and leave the signal level zero */
+@@ -1605,7 +1604,6 @@ static int wpa_scan_result_compar(const
+ 		return wb->qual - wa->qual;
+ 	return snr_b - snr_a;
+ #undef MIN
+-#undef IS_5GHZ
+ }
+ 
+ 
+@@ -1670,15 +1668,15 @@ static void dump_scan_res(struct wpa_sca
+ 	for (i = 0; i < scan_res->num; i++) {
+ 		struct wpa_scan_res *r = scan_res->res[i];
+ 		u8 *pos;
+-		if ((r->flags & (WPA_SCAN_LEVEL_DBM | WPA_SCAN_NOISE_INVALID))
+-		    == WPA_SCAN_LEVEL_DBM) {
++		if (r->flags & WPA_SCAN_LEVEL_DBM) {
+ 			int snr = r->level - r->noise;
++			int noise_valid = !(r->flags & WPA_SCAN_NOISE_INVALID);
++
+ 			wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
+-				   "noise=%d level=%d snr=%d%s flags=0x%x "
+-				   "age=%u",
++				   "noise=%d%s level=%d snr=%d%s flags=0x%x age=%u",
+ 				   MAC2STR(r->bssid), r->freq, r->qual,
+-				   r->noise, r->level, snr,
+-				   snr >= GREAT_SNR ? "*" : "", r->flags,
++				   r->noise, noise_valid ? "" : "~", r->level,
++				   snr, snr >= GREAT_SNR ? "*" : "", r->flags,
+ 				   r->age);
+ 		} else {
+ 			wpa_printf(MSG_EXCESSIVE, MACSTR " freq=%d qual=%d "
+@@ -1751,6 +1749,14 @@ static void filter_scan_res(struct wpa_s
+ }
+ 
+ 
++/*
++ * Noise floor values to use when we have signal strength
++ * measurements, but no noise floor measurments. These values were
++ * measured in an office environment with many APs.
++ */
++#define DEFAULT_NOISE_FLOOR_2GHZ (-89)
++#define DEFAULT_NOISE_FLOOR_5GHZ (-92)
++
+ /**
+  * wpa_supplicant_get_scan_results - Get scan results
+  * @wpa_s: Pointer to wpa_supplicant data
+@@ -1784,6 +1790,17 @@ wpa_supplicant_get_scan_results(struct w
+ 	}
+ 	filter_scan_res(wpa_s, scan_res);
+ 
++	for (i = 0; i < scan_res->num; i++) {
++		struct wpa_scan_res *scan_res_item = scan_res->res[i];
++
++		if (scan_res_item->flags & WPA_SCAN_NOISE_INVALID) {
++			scan_res_item->noise =
++				IS_5GHZ(scan_res_item->freq) ?
++				DEFAULT_NOISE_FLOOR_5GHZ :
++				DEFAULT_NOISE_FLOOR_2GHZ;
++		}
++	}
++
+ #ifdef CONFIG_WPS
+ 	if (wpas_wps_searching(wpa_s)) {
+ 		wpa_dbg(wpa_s, MSG_DEBUG, "WPS: Order scan results with WPS "




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