[PATCH v2 1/6] monitor: print START_TIME_TSF/BSSID values

[PATCH v2 1/6] monitor: print START_TIME_TSF/BSSID values

[James Prestwood]

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---
 monitor/nlmon.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/monitor/nlmon.c b/monitor/nlmon.c
index 94d16979..4c0e045f 100644
--- a/monitor/nlmon.c
+++ b/monitor/nlmon.c
@@ -5578,6 +5578,10 @@ static const struct attr_entry attr_table[] = {
 			"FTM Responder" },
 	{ NL80211_ATTR_FTM_RESPONDER_STATS,
 			"FTM Responder Stats" },
+	{ NL80211_ATTR_SCAN_START_TIME_TSF,
+			"Scan Start Time", ATTR_U64 },
+	{ NL80211_ATTR_SCAN_START_TIME_TSF_BSSID,
+			"Scan Start Time BSSID", ATTR_ADDRESS },
 	{ }
 };
 
-- 
2.17.1

[PATCH v2 2/6] scan: fix parent TSF parsing

[James Prestwood]

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The value coming from the kernel is in the same endianness as IWD, so
just parse it as a u64 rather than le64.
---
 src/scan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-v2:
 * Changed the commit description to match what was being changed. This
   commit description somehow got duplicated from a previously upstreamed
   commit adding parent TSF parsing

diff --git a/src/scan.c b/src/scan.c
index e74a69c1..e007ce5d 100644
--- a/src/scan.c
+++ b/src/scan.c
@@ -1076,7 +1076,7 @@ static struct scan_bss *scan_parse_attr_bss(struct l_genl_attr *attr)
 			if (len != sizeof(uint64_t))
 				goto fail;
 
-			bss->parent_tsf = l_get_le64(data);
+			bss->parent_tsf = l_get_u64(data);
 			break;
 		}
 	}
-- 
2.17.1

[PATCH v2 3/6] rrm: include actual parent TSF value

[James Prestwood]

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If the scan results included a parent TSF value use it.
---
 src/rrm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/rrm.c b/src/rrm.c
index 73cf01f2..2b0a22fb 100644
--- a/src/rrm.c
+++ b/src/rrm.c
@@ -270,8 +270,13 @@ static size_t build_report_for_bss(struct rrm_beacon_req_info *beacon,
 	to += 6;
 	/* Antenna identifier unknown */
 	*to++ = 0;
-	/* Parent TSF - zero */
-	memset(to, 0, 4);
+	/*
+	 * 802.11 9.4.2.22.7 Beacon report
+	 *
+	 * "The Parent TSF field contains the lower 4 octets of the measuring
+	 *  STA’s TSF timer value"
+	 */
+	l_put_le32((uint32_t)(bss->parent_tsf & 0xffffffff), to);
 	to += 4;
 
 	/*
-- 
2.17.1

[PATCH v2 4/6] scan: parse the scan start time

[James Prestwood]

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The kernel sends NL80211_ATTR_SCAN_START_TIME_TSF with CMD_TRIGGER and
RRM requires this value for beacon measurement reports. Since this
value is sent with CMD_TRIGGER we have to store it in the scan_context
and set it into the scan_bss when the scan finishes.
---
 src/scan.c | 13 +++++++++++++
 src/scan.h |  1 +
 2 files changed, 14 insertions(+)

diff --git a/src/scan.c b/src/scan.c
index e007ce5d..52ed102c 100644
--- a/src/scan.c
+++ b/src/scan.c
@@ -91,6 +91,9 @@ struct scan_context {
 	unsigned int start_cmd_id;
 	/* Non-zero if GET_SCAN is still running */
 	unsigned int get_scan_cmd_id;
+
+	/* The time the current scan was started. Reported in TRIGGER_SCAN */
+	uint64_t start_time_tsf;
 	/*
 	 * Whether the top request in the queue has triggered the current
 	 * scan.  May be set and cleared multiple times during a single
@@ -1312,6 +1315,7 @@ static void get_scan_callback(struct l_genl_msg *msg, void *user_data)
 	}
 
 	bss->time_stamp = results->time_stamp;
+	bss->start_time_tsf = sc->start_time_tsf;
 
 	scan_bss_compute_rank(bss);
 	l_queue_insert(results->bss_list, bss, scan_bss_rank_compare, NULL);
@@ -1439,6 +1443,7 @@ static void scan_notify(struct l_genl_msg *msg, void *user_data)
 	uint32_t wiphy_id;
 	struct scan_context *sc;
 	bool active_scan = false;
+	uint64_t start_time_tsf = 0;
 
 	cmd = l_genl_msg_get_command(msg);
 
@@ -1461,6 +1466,12 @@ static void scan_notify(struct l_genl_msg *msg, void *user_data)
 		case NL80211_ATTR_SCAN_SSIDS:
 			active_scan = true;
 			break;
+		case NL80211_ATTR_SCAN_START_TIME_TSF:
+			if (len != sizeof(uint64_t))
+				return;
+
+			start_time_tsf = l_get_u64(data);
+			break;
 		}
 	}
 
@@ -1543,6 +1554,8 @@ static void scan_notify(struct l_genl_msg *msg, void *user_data)
 		else
 			sc->state = SCAN_STATE_PASSIVE;
 
+		sc->start_time_tsf = start_time_tsf;
+
 		break;
 
 	case NL80211_CMD_SCAN_ABORTED:
diff --git a/src/scan.h b/src/scan.h
index 8fc2aa56..fcbbe285 100644
--- a/src/scan.h
+++ b/src/scan.h
@@ -67,6 +67,7 @@ struct scan_bss {
 	uint8_t hessid[6];
 	uint8_t *rc_ie;		/* Roaming consortium IE */
 	uint8_t hs20_version;
+	uint64_t start_time_tsf;
 	uint64_t parent_tsf;
 	bool mde_present : 1;
 	bool cc_present : 1;
-- 
2.17.1

[PATCH v2 5/6] rrm: include actual scan start time in report

[James Prestwood]

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---
 src/rrm.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/rrm.c b/src/rrm.c
index 2b0a22fb..a231f7e9 100644
--- a/src/rrm.c
+++ b/src/rrm.c
@@ -249,8 +249,7 @@ static size_t build_report_for_bss(struct rrm_beacon_req_info *beacon,
 
 	*to++ = beacon->oper_class;
 	*to++ = scan_freq_to_channel(bss->frequency, NULL);
-	/* skip start time */
-	memset(to, 0, 8);
+	l_put_le64(bss->start_time_tsf, to);
 	to += 8;
 	l_put_le16(beacon->duration, to);
 	to += 2;
-- 
2.17.1

[PATCH v2 6/6] rrm: add packed struct for beacon reports

[James Prestwood]

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build_report_for_bss was refactored to use this packed structure rather
than l_put_* APIs.
---
 src/rrm.c | 66 ++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 41 insertions(+), 25 deletions(-)

diff --git a/src/rrm.c b/src/rrm.c
index a231f7e9..adf55252 100644
--- a/src/rrm.c
+++ b/src/rrm.c
@@ -121,6 +121,21 @@ struct rrm_state {
 	uint64_t last_request;
 };
 
+/* 802.11, Section 9.4.2.22.7 */
+struct rrm_beacon_report {
+	uint8_t oper_class;
+	uint8_t channel;
+	__le64 scan_start_time;
+	__le16 duration;
+	uint8_t frame_info;
+	uint8_t rcpi;
+	uint8_t rsni;
+	uint8_t bssid[6];
+	uint8_t antenna_id;
+	__le32 parent_tsf;
+	uint8_t subelements[0];
+} __attribute__ ((packed));
+
 static struct l_queue *states;
 static struct l_genl_family *nl80211;
 static uint32_t netdev_watch;
@@ -224,6 +239,17 @@ static void rrm_build_measurement_report(struct rrm_request_info *info,
 		memcpy(to, report, report_len);
 }
 
+/* 802.11 Table 9-154 */
+static uint8_t mdb_to_rcpi(int32_t mdb)
+{
+	if (mdb <= 10950)
+		return 0;
+	else if (mdb >= -10950 && mdb < 0)
+		return ((uint8_t)((2 * (mdb + 11000)) / 100));
+	else
+		return 220;
+}
+
 /*
  * 802.11-2016 11.11.9.1 Beacon report
  *
@@ -245,38 +271,28 @@ static size_t build_report_for_bss(struct rrm_beacon_req_info *beacon,
 					struct scan_bss *bss,
 					uint8_t *to)
 {
-	uint8_t *start = to;
-
-	*to++ = beacon->oper_class;
-	*to++ = scan_freq_to_channel(bss->frequency, NULL);
-	l_put_le64(bss->start_time_tsf, to);
-	to += 8;
-	l_put_le16(beacon->duration, to);
-	to += 2;
-	*to++ = rrm_phy_type(bss);
-
-	/* 802.11 Table 9-154 - RCPI values */
-	if (bss->signal_strength < -10950)
-		*to++ = 0;
-	else if (bss->signal_strength >= -10950 && bss->signal_strength < 0)
-		*to++ = (uint8_t)((2 * (bss->signal_strength + 11000)) / 100);
-	else
-		*to++ = 220;
+	struct rrm_beacon_report *report = (struct rrm_beacon_report *) to;
+
+	report->oper_class = beacon->oper_class;
+	report->channel = scan_freq_to_channel(bss->frequency, NULL);
+	report->scan_start_time = bss->start_time_tsf;
+	report->duration = beacon->duration;
+	report->frame_info = rrm_phy_type(bss);
+	report->rcpi = mdb_to_rcpi(bss->signal_strength);
 
 	/* RSNI not available (could get this from GET_SURVEY) */
-	*to++ = 255;
-	memcpy(to, bss->addr, 6);
-	to += 6;
-	/* Antenna identifier unknown */
-	*to++ = 0;
+	report->rsni = 255;
+	memcpy(report->bssid, bss->addr, 6);
+
+	report->antenna_id = 0;
+
 	/*
 	 * 802.11 9.4.2.22.7 Beacon report
 	 *
 	 * "The Parent TSF field contains the lower 4 octets of the measuring
 	 *  STA’s TSF timer value"
 	 */
-	l_put_le32((uint32_t)(bss->parent_tsf & 0xffffffff), to);
-	to += 4;
+	report->parent_tsf = (uint32_t)bss->parent_tsf;
 
 	/*
 	 * TODO: Support optional subelements
@@ -284,7 +300,7 @@ static size_t build_report_for_bss(struct rrm_beacon_req_info *beacon,
 	 * (see "TODO: Support Reported Frame Body..." below)
 	 */
 
-	return to - start;
+	return sizeof(struct rrm_beacon_report);
 }
 
 static bool bss_in_request_range(struct rrm_beacon_req_info *beacon,
-- 
2.17.1

Re: [PATCH v2 1/6] monitor: print START_TIME_TSF/BSSID values

[Denis Kenzior]

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Hi James,

On 11/20/19 11:31 AM, James Prestwood wrote:
> ---
>   monitor/nlmon.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 

Patches 1-3 applied, thanks.

Regards,
-Denis

Re: [PATCH v2 4/6] scan: parse the scan start time

[Denis Kenzior]

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Hi James,

On 11/20/19 11:31 AM, James Prestwood wrote:
> The kernel sends NL80211_ATTR_SCAN_START_TIME_TSF with CMD_TRIGGER and
> RRM requires this value for beacon measurement reports. Since this
> value is sent with CMD_TRIGGER we have to store it in the scan_context
> and set it into the scan_bss when the scan finishes.

That seems rather expensive?  To store an 8 byte value in all the bsses 
that really belongs in the trigger callback?  Perhaps we should just 
pass it in as an additional argument.

Or since we have the scan_request id, perhaps it should be obtainable 
using that?  E.g. something like:

uint64_t scan_get_triggered_time(uint32_t id);

> ---
>   src/scan.c | 13 +++++++++++++
>   src/scan.h |  1 +
>   2 files changed, 14 insertions(+)
> 

Regards,
-Denis