2010-11-10 07:03:49

by Juuso Oikarinen

[permalink] [raw]
Subject: [PATCHv2] mac80211: Add function to get probe request template for current AP

From: Juuso Oikarinen <[email protected]>

Chipsets with hardware based connection monitoring need to autonomically
send directed probe-request frames to the AP (in the event of beacon loss,
for example.)

For the hardware to be able to do this, it requires a template for the frame
to transmit to the AP, filled in with the BSSID and SSID of the AP, but also
the supported rate IE's.

This patch adds a function to mac80211, which allows the hardware driver to
fetch this template after association, so it can be configured to the hardware.

Signed-off-by: Juuso Oikarinen <[email protected]>
---
v2: Add more documentation to the ieee80211_ap_probereq_get function

include/net/mac80211.h | 14 ++++++++++++++
net/mac80211/ieee80211_i.h | 4 ++++
net/mac80211/mlme.c | 24 ++++++++++++++++++++++++
net/mac80211/util.c | 23 ++++++++++++++++++-----
4 files changed, 60 insertions(+), 5 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 9fdf982..c0b6378 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2501,6 +2501,20 @@ void ieee80211_sta_block_awake(struct ieee80211_hw *hw,
struct ieee80211_sta *pubsta, bool block);

/**
+ * ieee80211_ap_probereq_get - retrieve a Probe Request template
+ * @hw: pointer obtained from ieee80211_alloc_hw().
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ *
+ * Creates a Probe Request template which can, for example, be uploaded to
+ * hardware. The template is filled with bssid, ssid and supported rate
+ * information. This function must only be called from within the
+ * .bss_info_changed callback function. The function is only useful in managed
+ * mode while the interface is associated, otherwise it will return NULL.
+ */
+struct sk_buff *ieee80211_ap_probereq_get(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif);
+
+/**
* ieee80211_beacon_loss - inform hardware does not receive beacons
*
* @vif: &struct ieee80211_vif pointer from the add_interface callback.
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index b80c386..59a1d38 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1287,6 +1287,10 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
const u8 *ie, size_t ie_len,
enum ieee80211_band band, u32 rate_mask,
u8 channel);
+struct sk_buff *ieee80211_build_probe_req(struct ieee80211_sub_if_data *sdata,
+ u8 *dst,
+ const u8 *ssid, size_t ssid_len,
+ const u8 *ie, size_t ie_len);
void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,
const u8 *ssid, size_t ssid_len,
const u8 *ie, size_t ie_len);
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index a3a9421..dfc4a31 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1108,6 +1108,30 @@ static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata,
mutex_unlock(&ifmgd->mtx);
}

+struct sk_buff *ieee80211_ap_probereq_get(struct ieee80211_hw *hw,
+ struct ieee80211_vif *vif)
+{
+ struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+ struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+ struct sk_buff *skb;
+ const u8 *ssid;
+
+ if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_STATION))
+ return NULL;
+
+ ASSERT_MGD_MTX(ifmgd);
+
+ if (!ifmgd->associated)
+ return NULL;
+
+ ssid = ieee80211_bss_get_ie(ifmgd->associated, WLAN_EID_SSID);
+ skb = ieee80211_build_probe_req(sdata, ifmgd->associated->bssid,
+ ssid + 2, ssid[1], NULL, 0);
+
+ return skb;
+}
+EXPORT_SYMBOL(ieee80211_ap_probereq_get);
+
static void __ieee80211_connection_loss(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 0b6fc92..885713d 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1011,9 +1011,10 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer,
return pos - buffer;
}

-void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,
- const u8 *ssid, size_t ssid_len,
- const u8 *ie, size_t ie_len)
+struct sk_buff *ieee80211_build_probe_req(struct ieee80211_sub_if_data *sdata,
+ u8 *dst,
+ const u8 *ssid, size_t ssid_len,
+ const u8 *ie, size_t ie_len)
{
struct ieee80211_local *local = sdata->local;
struct sk_buff *skb;
@@ -1027,7 +1028,7 @@ void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,
if (!buf) {
printk(KERN_DEBUG "%s: failed to allocate temporary IE "
"buffer\n", sdata->name);
- return;
+ return NULL;
}

chan = ieee80211_frequency_to_channel(
@@ -1050,8 +1051,20 @@ void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,
}

IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
- ieee80211_tx_skb(sdata, skb);
kfree(buf);
+
+ return skb;
+}
+
+void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst,
+ const u8 *ssid, size_t ssid_len,
+ const u8 *ie, size_t ie_len)
+{
+ struct sk_buff *skb;
+
+ skb = ieee80211_build_probe_req(sdata, dst, ssid, ssid_len, ie, ie_len);
+ if (skb)
+ ieee80211_tx_skb(sdata, skb);
}

u32 ieee80211_sta_get_rates(struct ieee80211_local *local,
--
1.7.1



2010-11-10 16:00:11

by Johannes Berg

[permalink] [raw]
Subject: Re: [PATCHv2] mac80211: Add function to get probe request template for current AP

On Wed, 2010-11-10 at 09:03 +0200, [email protected] wrote:

> + * .bss_info_changed callback function. The function is only useful in managed
> + * mode while the interface is associated, otherwise it will return NULL.

Since you have a WARN_ON, wouldn't it be more honest to document that
it's invalid to call in other modes?

johannes