[PATCH 0/2] mac80211: client-side P2P powersave

[PATCH 0/2] mac80211: client-side P2P powersave

[Johannes Berg]

Implement passing the P2P powersave parameters (except NoA
schedules) to the mac80211 hardware driver. To do this, I
introduced a generic function to get a copy of some P2P
attribute into a buffer, I did it that way because of the
potential for fragmentation into multiple IEs.

The only change over the RFC is that I now use the correct
attribute ID definition from Arend's patch.

johannes

[PATCH 1/2] wireless: add utility function to get P2P attribute

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Parsing the P2P attributes can be tricky as their
contents can be split across multiple (vendor) IEs.
Thus, it's not possible to parse them like IEs (by
returning a pointer to the data.) Instead, provide
a function that copies the attribute data into a
caller-provided buffer and returns the size needed
(useful in case the buffer was too small.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/cfg80211.h | 19 ++++++++++
 net/wireless/util.c    | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 118 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 83a2c82..ae6d5e5 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3623,6 +3623,25 @@ u32 cfg80211_calculate_bitrate(struct rate_info *rate);
  */
 void cfg80211_unregister_wdev(struct wireless_dev *wdev);
 
+/**
+ * cfg80211_get_p2p_attr - find and copy a P2P attribute from IE buffer
+ * @ies: the input IE buffer
+ * @len: the input length
+ * @attr: the attribute ID to find
+ * @buf: output buffer, can be %NULL if the data isn't needed, e.g.
+ *	if the function is only called to get the needed buffer size
+ * @bufsize: size of the output buffer
+ *
+ * The function finds a given P2P attribute in the (vendor) IEs and
+ * copies its contents to the given buffer.
+ *
+ * The return value is a negative error code (-%EILSEQ or -%ENOENT) if
+ * the data is malformed or the attribute can't be found (respectively),
+ * or the length of the found attribute (which can be zero).
+ */
+unsigned int cfg80211_get_p2p_attr(const u8 *ies, unsigned int len,
+				   u8 attr, u8 *buf, unsigned int bufsize);
+
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
 
 /* wiphy_printk helpers, similar to dev_printk */
diff --git a/net/wireless/util.c b/net/wireless/util.c
index cf11239..2964223 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -980,6 +980,105 @@ u32 cfg80211_calculate_bitrate(struct rate_info *rate)
 }
 EXPORT_SYMBOL(cfg80211_calculate_bitrate);
 
+unsigned int cfg80211_get_p2p_attr(const u8 *ies, unsigned int len,
+				   u8 attr, u8 *buf, unsigned int bufsize)
+{
+	u8 *out = buf;
+	u16 attr_remaining = 0;
+	bool desired_attr = false;
+	u16 desired_len = 0;
+
+	while (len > 0) {
+		unsigned int iedatalen;
+		unsigned int copy;
+		const u8 *iedata;
+
+		if (len < 2)
+			return -EILSEQ;
+		iedatalen = ies[1];
+		if (iedatalen + 2 > len)
+			return -EILSEQ;
+
+		if (ies[0] != WLAN_EID_VENDOR_SPECIFIC)
+			goto cont;
+
+		if (iedatalen < 4)
+			goto cont;
+
+		iedata = ies + 2;
+
+		/* check WFA OUI, P2P subtype */
+		if (iedata[0] != 0x50 || iedata[1] != 0x6f ||
+		    iedata[2] != 0x9a || iedata[3] != 0x09)
+			goto cont;
+
+		iedatalen -= 4;
+		iedata += 4;
+
+		/* check attribute continuation into this IE */
+		copy = min_t(unsigned int, attr_remaining, iedatalen);
+		if (copy && desired_attr) {
+			desired_len += copy;
+			if (out) {
+				memcpy(out, iedata, min(bufsize, copy));
+				out += min(bufsize, copy);
+				bufsize -= min(bufsize, copy);
+			}
+
+
+			if (copy == attr_remaining)
+				return desired_len;
+		}
+
+		attr_remaining -= copy;
+		if (attr_remaining)
+			goto cont;
+
+		iedatalen -= copy;
+		iedata += copy;
+
+		while (iedatalen > 0) {
+			u16 attr_len;
+
+			/* P2P attribute ID & size must fit */
+			if (iedatalen < 3)
+				return -EILSEQ;
+			desired_attr = iedata[0] == attr;
+			attr_len = get_unaligned_le16(iedata + 1);
+			iedatalen -= 3;
+			iedata += 3;
+
+			copy = min_t(unsigned int, attr_len, iedatalen);
+
+			if (desired_attr) {
+				desired_len += copy;
+				if (out) {
+					memcpy(out, iedata, min(bufsize, copy));
+					out += min(bufsize, copy);
+					bufsize -= min(bufsize, copy);
+				}
+
+				if (copy == attr_len)
+					return desired_len;
+			}
+
+			iedata += copy;
+			iedatalen -= copy;
+			attr_remaining = attr_len - copy;
+		}
+
+ cont:
+		len -= ies[1] + 2;
+		ies += ies[1] + 2;
+	}
+
+	if (attr_remaining && desired_attr)
+		return -EILSEQ;
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL(cfg80211_get_p2p_attr);
+
 bool ieee80211_operating_class_to_band(u8 operating_class,
 				       enum ieee80211_band *band)
 {
-- 
1.8.0

[PATCH 2/2] mac80211: pass P2P powersave parameters to driver

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

While connected to a GO, parse the P2P NoA attribute
and pass the CT Window and opportunistic powersave
parameters to the driver.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/mac80211.h     |  7 +++++++
 net/mac80211/ieee80211_i.h |  2 ++
 net/mac80211/mlme.c        | 40 ++++++++++++++++++++++++++++++++++++++++
 net/mac80211/trace.h       |  4 ++++
 4 files changed, 53 insertions(+)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index dfa589b..23803ad 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -208,6 +208,8 @@ struct ieee80211_chanctx_conf {
  * @BSS_CHANGED_AP_PROBE_RESP: Probe Response changed for this BSS (AP mode)
  * @BSS_CHANGED_PS: PS changed for this BSS (STA mode)
  * @BSS_CHANGED_TXPOWER: TX power setting changed for this interface
+ * @BSS_CHANGED_P2P_PS: P2P powersave settings (CTWindow, opportunistic PS)
+ *	changed (currently only in P2P client mode, GO mode will be later)
  */
 enum ieee80211_bss_change {
 	BSS_CHANGED_ASSOC		= 1<<0,
@@ -229,6 +231,7 @@ enum ieee80211_bss_change {
 	BSS_CHANGED_AP_PROBE_RESP	= 1<<16,
 	BSS_CHANGED_PS			= 1<<17,
 	BSS_CHANGED_TXPOWER		= 1<<18,
+	BSS_CHANGED_P2P_PS		= 1<<19,
 
 	/* when adding here, make sure to change ieee80211_reconfig */
 };
@@ -312,6 +315,8 @@ enum ieee80211_rssi_event {
  * @ssid_len: Length of SSID given in @ssid.
  * @hidden_ssid: The SSID of the current vif is hidden. Only valid in AP-mode.
  * @txpower: TX power in dBm
+ * @p2p_ctwindow: P2P CTWindow, only for P2P client interfaces
+ * @p2p_oppps: P2P opportunistic PS is enabled
  */
 struct ieee80211_bss_conf {
 	const u8 *bssid;
@@ -345,6 +350,8 @@ struct ieee80211_bss_conf {
 	size_t ssid_len;
 	bool hidden_ssid;
 	int txpower;
+	u8 p2p_ctwindow;
+	bool p2p_oppps;
 };
 
 /**
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 37c08d3..904b4d8 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -473,6 +473,8 @@ struct ieee80211_if_managed {
 
 	u8 use_4addr;
 
+	u8 p2p_noa_index;
+
 	/* Signal strength from the last Beacon frame in the current BSS. */
 	int last_beacon_signal;
 
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 35afbbc..856e562 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1364,6 +1364,22 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
 
 	sdata->u.mgd.flags |= IEEE80211_STA_RESET_SIGNAL_AVE;
 
+	if (sdata->vif.p2p) {
+		u8 noa[2];
+		int ret;
+
+		ret = cfg80211_get_p2p_attr(cbss->information_elements,
+					    cbss->len_information_elements,
+					    IEEE80211_P2P_ATTR_ABSENCE_NOTICE,
+					    noa, sizeof(noa));
+		if (ret >= 2) {
+			bss_conf->p2p_oppps = noa[1] & 0x80;
+			bss_conf->p2p_ctwindow = noa[1] & 0x7f;
+			bss_info_changed |= BSS_CHANGED_P2P_PS;
+			sdata->u.mgd.p2p_noa_index = noa[0];
+		}
+	}
+
 	/* just to be sure */
 	ieee80211_stop_poll(sdata);
 
@@ -1486,6 +1502,9 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
 	changed |= BSS_CHANGED_ASSOC;
 	sdata->vif.bss_conf.assoc = false;
 
+	sdata->vif.bss_conf.p2p_ctwindow = 0;
+	sdata->vif.bss_conf.p2p_oppps = false;
+
 	/* on the next assoc, re-program HT parameters */
 	memset(&ifmgd->ht_capa, 0, sizeof(ifmgd->ht_capa));
 	memset(&ifmgd->ht_capa_mask, 0, sizeof(ifmgd->ht_capa_mask));
@@ -2617,6 +2636,27 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 		}
 	}
 
+	if (sdata->vif.p2p) {
+		u8 noa[2];
+		int ret;
+
+		ret = cfg80211_get_p2p_attr(mgmt->u.beacon.variable,
+					    len - baselen,
+					    IEEE80211_P2P_ATTR_ABSENCE_NOTICE,
+					    noa, sizeof(noa));
+		if (ret >= 2 && sdata->u.mgd.p2p_noa_index != noa[0]) {
+			bss_conf->p2p_oppps = noa[1] & 0x80;
+			bss_conf->p2p_ctwindow = noa[1] & 0x7f;
+			changed |= BSS_CHANGED_P2P_PS;
+			sdata->u.mgd.p2p_noa_index = noa[0];
+			/*
+			 * make sure we update all information, the CRC
+			 * mechanism doesn't look at P2P attributes.
+			 */
+			ifmgd->beacon_crc_valid = false;
+		}
+	}
+
 	if (ncrc == ifmgd->beacon_crc && ifmgd->beacon_crc_valid)
 		return;
 	ifmgd->beacon_crc = ncrc;
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index eeebbd9..7794e53 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -343,6 +343,8 @@ TRACE_EVENT(drv_bss_info_changed,
 		__dynamic_array(u8, ssid, info->ssid_len);
 		__field(bool, hidden_ssid);
 		__field(int, txpower)
+		__field(u8, p2p_ctwindow)
+		__field(bool, p2p_oppps)
 	),
 
 	TP_fast_assign(
@@ -378,6 +380,8 @@ TRACE_EVENT(drv_bss_info_changed,
 		memcpy(__get_dynamic_array(ssid), info->ssid, info->ssid_len);
 		__entry->hidden_ssid = info->hidden_ssid;
 		__entry->txpower = info->txpower;
+		__entry->p2p_ctwindow = info->p2p_ctwindow;
+		__entry->p2p_oppps = info->p2p_oppps;
 	),
 
 	TP_printk(
-- 
1.8.0

Re: [PATCH 0/2] mac80211: client-side P2P powersave

[Johannes Berg]

On Mon, 2012-11-05 at 15:40 +0100, Johannes Berg wrote:
> Implement passing the P2P powersave parameters (except NoA
> schedules) to the mac80211 hardware driver. To do this, I
> introduced a generic function to get a copy of some P2P
> attribute into a buffer, I did it that way because of the
> potential for fragmentation into multiple IEs.
> 
> The only change over the RFC is that I now use the correct
> attribute ID definition from Arend's patch.

Applied both.

johannes