2011-08-29 08:56:52

by Vivek Natarajan

Subject: [PATCH] wpa_supplicant: Modify bgscan based roaming behaviour.

Cancel background scan based roaming behavior if the driver
is capable of handling roaming in the firmware. For fullmac
drivers like ath6kl, the roaming logic is handled in the
firmware and for supplicant to initiate roam, the station
has to disconnect completely and then reconnect with the
new AP which takes a longer time without preauth.

Currently, if the supplicant also tries to roam, all requests
are rejected by cfg80211 resulting in a spam of log.

Signed-off-by: Vivek Natarajan <[email protected]>
---
src/drivers/driver.h | 2 ++
src/drivers/driver_nl80211.c | 9 +++++++++
src/drivers/nl80211_copy.h | 1 +
wpa_supplicant/events.c | 7 +++++++
4 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/src/drivers/driver.h b/src/drivers/driver.h
index 67c5631..804ce93 100644
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -675,6 +675,8 @@ struct wpa_driver_capa {
#define WPA_DRIVER_FLAGS_EAPOL_TX_STATUS 0x00010000
/* Driver indicates TX status events for Deauth/Disassoc frames */
#define WPA_DRIVER_FLAGS_DEAUTH_TX_STATUS 0x00020000
+/* Driver supports roaming in firmware */
+#define WPA_DRIVER_FLAGS_FW_ROAMING 0x00040000
unsigned int flags;

int max_scan_ssids;
diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
index e49e714..5fbf46b 100644
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -1640,6 +1640,7 @@ struct wiphy_info_data {
int connect_supported;
int offchan_tx_supported;
int max_remain_on_chan;
+ int fw_roam;
};


@@ -1695,6 +1696,9 @@ static int wiphy_info_handler(struct nl_msg *msg, void *arg)
if (tb[NL80211_ATTR_OFFCHANNEL_TX_OK])
info->offchan_tx_supported = 1;

+ if (tb[NL80211_ATTR_ROAM_SUPPORT])
+ info->fw_roam = 1;
+
if (tb[NL80211_ATTR_MAX_REMAIN_ON_CHANNEL_DURATION])
info->max_remain_on_chan =
nla_get_u32(tb[NL80211_ATTR_MAX_REMAIN_ON_CHANNEL_DURATION]);
@@ -1768,6 +1772,11 @@ static int wpa_driver_nl80211_capa(struct wpa_driver_nl80211_data *drv)
drv->capa.flags |= WPA_DRIVER_FLAGS_OFFCHANNEL_TX;
}

+ if (info.fw_roam) {
+ wpa_printf(MSG_DEBUG, "nl80211: Using driver-based roaming");
+ drv->capa.flags |= WPA_DRIVER_FLAGS_FW_ROAMING;
+ }
+
drv->capa.flags |= WPA_DRIVER_FLAGS_SANE_ERROR_CODES;
drv->capa.flags |= WPA_DRIVER_FLAGS_SET_KEYS_AFTER_ASSOC_DONE;
if (info.p2p_supported)
diff --git a/src/drivers/nl80211_copy.h b/src/drivers/nl80211_copy.h
index 3769303..ca05807 100644
--- a/src/drivers/nl80211_copy.h
+++ b/src/drivers/nl80211_copy.h
@@ -1252,6 +1252,7 @@ enum nl80211_attrs {
NL80211_ATTR_IE_PROBE_RESP,
NL80211_ATTR_IE_ASSOC_RESP,

+ NL80211_ATTR_ROAM_SUPPORT,
/* add attributes here, update the policy in nl80211.c */

__NL80211_ATTR_AFTER_LAST,
diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index a307eda..57c987b 100644
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -718,6 +718,13 @@ void wpa_supplicant_connect(struct wpa_supplicant *wpa_s,
return;
}

+ if ((wpa_s->current_ssid == ssid) &&
+ (wpa_s->drv_flags & WPA_DRIVER_FLAGS_FW_ROAMING)) {
+ wpa_dbg(wpa_s, MSG_DEBUG, "Cancel supplicant roaming as "
+ "driver has the capability");
+ return;
+ }
+
/*
* Do not trigger new association unless the BSSID has changed or if
* reassociation is requested. If we are in process of associating with
--
1.7.1

2011-09-26 11:31:07

by Jouni Malinen

Subject: Re: [PATCH] wpa_supplicant: Modify bgscan based roaming behaviour.

On Mon, Aug 29, 2011 at 02:26:45PM +0530, Vivek Natarajan wrote:
> Cancel background scan based roaming behavior if the driver
> is capable of handling roaming in the firmware. For fullmac
> drivers like ath6kl, the roaming logic is handled in the
> firmware and for supplicant to initiate roam, the station
> has to disconnect completely and then reconnect with the
> new AP which takes a longer time without preauth.
>
> Currently, if the supplicant also tries to roam, all requests
> are rejected by cfg80211 resulting in a spam of log.

I applied the driver.h and driver_nl80211.c parts to get the new driver
flag for this, but the change to events.c did not look correct, so I
left that out. wpa_supplicant will need quite a bit more changes to be
able to work in ap_scan=2 like way in the default ap_scan=1 mode when
the driver indicates this BSS-selection-in-driver(firmware) capability.
Those changes will take care of not even getting to the
wpa_supplicant_connect(), so there should be no need to modify it in the
way done in this patch.

--
Jouni Malinen PGP id EFC895FA