2010-11-11 06:50:32

by Juuso Oikarinen

[permalink] [raw]
Subject: [PATCHv3] 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
v3: Added some honesty to the documentation of ieee80211_ap_probereq_get

include/net/mac80211.h | 15 +++++++++++++++
net/mac80211/ieee80211_i.h | 4 ++++
net/mac80211/mlme.c | 24 ++++++++++++++++++++++++
net/mac80211/util.c | 23 ++++++++++++++++++-----
4 files changed, 61 insertions(+), 5 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 9fdf982..773694b 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2501,6 +2501,21 @@ 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 and only in managed mode. The function
+ * is only useful when 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



2010-11-11 17:53:32

by Johannes Berg

[permalink] [raw]
Subject: Re: [PATCHv3] mac80211: Add function to get probe request template for current AP

On Thu, 2010-11-11 at 08:50 +0200, [email protected] wrote:
> 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
> v3: Added some honesty to the documentation of ieee80211_ap_probereq_get

:-)

Acked-by: Johannes Berg <[email protected]>

> include/net/mac80211.h | 15 +++++++++++++++
> net/mac80211/ieee80211_i.h | 4 ++++
> net/mac80211/mlme.c | 24 ++++++++++++++++++++++++
> net/mac80211/util.c | 23 ++++++++++++++++++-----
> 4 files changed, 61 insertions(+), 5 deletions(-)
>
> diff --git a/include/net/mac80211.h b/include/net/mac80211.h
> index 9fdf982..773694b 100644
> --- a/include/net/mac80211.h
> +++ b/include/net/mac80211.h
> @@ -2501,6 +2501,21 @@ 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 and only in managed mode. The function
> + * is only useful when 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,