On 2-12-2016 22:59, Jouni Malinen wrote:
> From: vamsi krishna <vamsin@xxxxxxxxxxxxxxxx>
>
> Enhance sched scan to support option of finding a better BSS while in
> connected state. Firmware scans the medium and reports when it finds a
> known BSS which has better RSSI than the current connected BSS. New
> attributes to specify the relative RSSI (compared to the current BSS)
> are added to the sched scan to implement this.
>
> Signed-off-by: vamsi krishna <vamsin@xxxxxxxxxxxxxxxx>
> Signed-off-by: Jouni Malinen <jouni@xxxxxxxxxxxxxxxx>
> ---
> include/net/cfg80211.h | 19 +++++++++++++++++++
> include/uapi/linux/nl80211.h | 18 ++++++++++++++++++
> net/wireless/nl80211.c | 29 +++++++++++++++++++++++++++--
> 3 files changed, 64 insertions(+), 2 deletions(-)
>
> v2: address comments from Luca, Arend, and Johannes
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index ef42749..dcdd0c4 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -1626,6 +1626,22 @@ struct cfg80211_sched_scan_plan {
> * cycle. The driver may ignore this parameter and start
> * immediately (or at any other time), if this feature is not
> * supported.
> + * @relative_rssi: Relative RSSI threshold in dB to restrict scan result
> + * reporting in connected state to cases where a matching BSS is determined
> + * to have better RSSI than the current connected BSS. The relative RSSI
> + * threshold values are ignored in disconnected state.
> + * @relative_rssi_5g_pref: The amount of RSSI preference in dB that is given to
> + * a 5 GHz BSS over 2.4 GHz BSS while looking for better BSSs in connected
> + * state. A negative value can be passed if 2.4 GHz band should be given
> + * priority to 5 GHz band.
> + * If the current connected BSS is in the 2.4 GHz band, other BSSs in the
> + * 2.4 GHz band to be reported should have better RSSI by @relative_rssi
> + * and other BSSs in the 5 GHz band to be reported should have better RSSI
> + * by (@relative_rssi - @relative_rssi_5g_pref).
> + * If the current connected BSS is in the 5 GHz band, other BSSs in the
> + * 2.4 GHz band to be reported should have better RSSI by
> + * (@relative_rssi + @relative_rssi_5g_pref) and other BSSs in the 5 GHz
> + * band to be reported should have better RSSI by by @relative_rssi.
The choice of these attributes makes the implicit assumption that the
BSS-es in 5G are preferred. The relative_rssi_5g_pref is actually more a
bonus or penalty is negative value is used. I guess for speed junkies
that want their 11ac card maxed out that is true, but if you need to
cross a couple of concrete floors you might want to stick with 2.4G.
I introduced a similar attribute to be provided in the
NL80211_CMD_CONNECT (see [1]).
Regards,
Arend
[1] http://lxr.free-electrons.com/source/include/uapi/linux/nl80211.h#L1815
> */
> struct cfg80211_sched_scan_request {
> struct cfg80211_ssid *ssids;
> @@ -1645,6 +1661,9 @@ struct cfg80211_sched_scan_request {
> u8 mac_addr[ETH_ALEN] __aligned(2);
> u8 mac_addr_mask[ETH_ALEN] __aligned(2);
>
> + s8 relative_rssi;
> + s8 relative_rssi_5g_pref;
> +
> /* internal */
> struct wiphy *wiphy;
> struct net_device *dev;
> diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
> index 6b76e3b..fc29bdb 100644
> --- a/include/uapi/linux/nl80211.h
> +++ b/include/uapi/linux/nl80211.h
> @@ -1980,6 +1980,17 @@ enum nl80211_commands {
> * @NL80211_ATTR_BSSID: The BSSID of the AP. Note that %NL80211_ATTR_MAC is also
> * used in various commands/events for specifying the BSSID.
> *
> + * @NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI: Relative RSSI threshold by which
> + * other BSSs has to be better than the current connected BSS so that they
> + * get reported to user space. This will give an opportunity to userspace
> + * to consider connecting to other matching BSSs which have better RSSI
> + * than the current connected BSS by using an offloaded operation to avoid
> + * unnecessary wakeups.
> + *
> + * @NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI_5G_PREF: The amount of RSSI preference
> + * to be given to 5 GHz APs over 2.4 GHz APs while searching for better
> + * BSSs than the current connected BSS.
> + *
> * @NUM_NL80211_ATTR: total number of nl80211_attrs available
> * @NL80211_ATTR_MAX: highest attribute number currently defined
> * @__NL80211_ATTR_AFTER_LAST: internal use
> @@ -2386,6 +2397,9 @@ enum nl80211_attrs {
>
> NL80211_ATTR_BSSID,
>
> + NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI,
> + NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI_5G_PREF,
> +
> /* add attributes here, update the policy in nl80211.c */
>
> __NL80211_ATTR_AFTER_LAST,
> @@ -4697,6 +4711,9 @@ enum nl80211_feature_flags {
> * configuration (AP/mesh) with VHT rates.
> * @NL80211_EXT_FEATURE_FILS_STA: This driver supports Fast Initial Link Setup
> * with user space SME (NL80211_CMD_AUTHENTICATE) in station mode.
> + * @NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI: The driver supports sched_scan
> + * for reporting BSSs with better RSSI than the current connected BSS
> + * (%NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI).
> *
> * @NUM_NL80211_EXT_FEATURES: number of extended features.
> * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
> @@ -4712,6 +4729,7 @@ enum nl80211_ext_feature_index {
> NL80211_EXT_FEATURE_BEACON_RATE_HT,
> NL80211_EXT_FEATURE_BEACON_RATE_VHT,
> NL80211_EXT_FEATURE_FILS_STA,
> + NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI,
>
> /* add new features before the definition below */
> NUM_NL80211_EXT_FEATURES,
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 7762231..549f239 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -405,6 +405,8 @@ enum nl80211_multicast_groups {
> [NL80211_ATTR_FILS_NONCES] = { .len = 2 * FILS_NONCE_LEN },
> [NL80211_ATTR_MULTICAST_TO_UNICAST_ENABLED] = { .type = NLA_FLAG, },
> [NL80211_ATTR_BSSID] = { .len = ETH_ALEN },
> + [NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI] = { .type = NLA_S8 },
> + [NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI_5G_PREF] = { .type = NLA_S8 },
> };
>
> /* policy for the key attributes */
> @@ -6950,6 +6952,12 @@ static int nl80211_abort_scan(struct sk_buff *skb, struct genl_info *info)
> if (!n_plans || n_plans > wiphy->max_sched_scan_plans)
> return ERR_PTR(-EINVAL);
>
> + if (!wiphy_ext_feature_isset(
> + wiphy, NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI) &&
> + (attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI] ||
> + attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI_5G_PREF]))
> + return ERR_PTR(-EINVAL);
> +
> request = kzalloc(sizeof(*request)
> + sizeof(*request->ssids) * n_ssids
> + sizeof(*request->match_sets) * n_match_sets
> @@ -7156,6 +7164,14 @@ static int nl80211_abort_scan(struct sk_buff *skb, struct genl_info *info)
> request->delay =
> nla_get_u32(attrs[NL80211_ATTR_SCHED_SCAN_DELAY]);
>
> + if (attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI])
> + request->relative_rssi = nla_get_s8(
> + attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI]);
> +
> + if (attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI_5G_PREF])
> + request->relative_rssi_5g_pref = nla_get_s8(
> + attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI_5G_PREF]);
> +
> err = nl80211_parse_sched_scan_plans(wiphy, n_plans, request, attrs);
> if (err)
> goto out_free;
> @@ -9649,7 +9665,8 @@ static int nl80211_send_wowlan_tcp(struct sk_buff *msg,
> return 0;
> }
>
> -static int nl80211_send_wowlan_nd(struct sk_buff *msg,
> +static int nl80211_send_wowlan_nd(struct wiphy *wiphy,
> + struct sk_buff *msg,
> struct cfg80211_sched_scan_request *req)
> {
> struct nlattr *nd, *freqs, *matches, *match, *scan_plans, *scan_plan;
> @@ -9670,6 +9687,14 @@ static int nl80211_send_wowlan_nd(struct sk_buff *msg,
> if (nla_put_u32(msg, NL80211_ATTR_SCHED_SCAN_DELAY, req->delay))
> return -ENOBUFS;
>
> + if (wiphy_ext_feature_isset(
> + wiphy, NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI) &&
> + (nla_put_s8(msg, NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI,
> + req->relative_rssi) ||
> + nla_put_s8(msg, NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI_5G_PREF,
> + req->relative_rssi_5g_pref)))
> + return -ENOBUFS;
> +
> freqs = nla_nest_start(msg, NL80211_ATTR_SCAN_FREQUENCIES);
> if (!freqs)
> return -ENOBUFS;
> @@ -9783,7 +9808,7 @@ static int nl80211_get_wowlan(struct sk_buff *skb, struct genl_info *info)
> goto nla_put_failure;
>
> if (nl80211_send_wowlan_nd(
> - msg,
> + &rdev->wiphy, msg,
> rdev->wiphy.wowlan_config->nd_config))
> goto nla_put_failure;
>
>
