On 2-12-2016 22:59, Jouni Malinen wrote: > From: vamsi krishna <[email protected]> > > 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 <[email protected]> > Signed-off-by: Jouni Malinen <[email protected]> > --- > 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; > >
