3 files changed, 39 insertions, 2 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index b1f84b05c67e..572005981366 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1701,8 +1701,14 @@ struct cfg80211_ibss_params {
  *
  * @channel: The channel to use or %NULL if not specified (auto-select based
  *      on scan results)
+ * @channel_hint: The channel of the recommended BSS for initial connection or
+ *      %NULL if not specified
  * @bssid: The AP BSSID or %NULL if not specified (auto-select based on scan
  *      results)
+ * @bssid_hint: The recommended AP BSSID for initial connection to the BSS or
+ *      %NULL if not specified. Unlike the @bssid parameter, the driver is
+ *      allowed to ignore this @bssid_hint if it has knowledge of a better BSS
+ *      to use.
  * @ssid: SSID
  * @ssid_len: Length of ssid in octets
  * @auth_type: Authentication type (algorithm)
@@ -1725,7 +1731,9 @@ struct cfg80211_ibss_params {
  */
 struct cfg80211_connect_params {
         struct ieee80211_channel *channel;
+        struct ieee80211_channel *channel_hint;
         u8 *bssid;
+        const u8 *bssid_hint;
         u8 *ssid;
         size_t ssid_len;
         enum nl80211_auth_type auth_type;
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 91054fd660e0..e57de3318068 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -418,8 +418,18 @@
  *      %NL80211_ATTR_SSID attribute, and can optionally specify the association
  *      IEs in %NL80211_ATTR_IE, %NL80211_ATTR_AUTH_TYPE, %NL80211_ATTR_USE_MFP,
  *      %NL80211_ATTR_MAC, %NL80211_ATTR_WIPHY_FREQ, %NL80211_ATTR_CONTROL_PORT,
- *      %NL80211_ATTR_CONTROL_PORT_ETHERTYPE and
- *      %NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT.
+ *      %NL80211_ATTR_CONTROL_PORT_ETHERTYPE,
+ *      %NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT, %NL80211_ATTR_MAC_HINT, and
+ *      %NL80211_ATTR_WIPHY_FREQ_HINT.
+ *      If included, %NL80211_ATTR_MAC and %NL80211_ATTR_WIPHY_FREQ are
+ *      restrictions on BSS selection, i.e., they effectively prevent roaming
+ *      within the ESS. %NL80211_ATTR_MAC_HINT and %NL80211_ATTR_WIPHY_FREQ_HINT
+ *      can be included to provide a recommendation of the initial BSS while
+ *      allowing the driver to roam to other BSSes within the ESS and also to
+ *      ignore this recommendation if the indicated BSS is not ideal. Only one
+ *      set of BSSID,frequency parameters is used (i.e., either the enforcing
+ *      %NL80211_ATTR_MAC,%NL80211_ATTR_WIPHY_FREQ or the less strict
+ *      %NL80211_ATTR_MAC_HINT and %NL80211_ATTR_WIPHY_FREQ_HINT).
  *      Background scan period can optionally be
  *      specified in %NL80211_ATTR_BG_SCAN_PERIOD,
  *      if not specified default background scan configuration
@@ -1555,6 +1565,9 @@ enum nl80211_commands {
  *      data is in the format defined for the payload of the QoS Map Set element
  *      in IEEE Std 802.11-2012, 8.4.2.97.
  *
+ * @NL80211_ATTR_MAC_HINT: MAC address recommendation as initial BSS
+ * @NL80211_ATTR_WIPHY_FREQ_HINT: frequency of the recommended initial BSS
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -1883,6 +1896,9 @@ enum nl80211_attrs {
 
         NL80211_ATTR_QOS_MAP,
 
+        NL80211_ATTR_MAC_HINT,
+        NL80211_ATTR_WIPHY_FREQ_HINT,
+
         /* add attributes here, update the policy in nl80211.c */
 
         __NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 7a742594916e..6e7d580ec645 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -382,6 +382,8 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
         [NL80211_ATTR_VENDOR_DATA] = { .type = NLA_BINARY },
         [NL80211_ATTR_QOS_MAP] = { .type = NLA_BINARY,
                                    .len = IEEE80211_QOS_MAP_LEN_MAX },
+        [NL80211_ATTR_MAC_HINT] = { .len = ETH_ALEN },
+        [NL80211_ATTR_WIPHY_FREQ_HINT] = { .type = NLA_U32 },
 };
 
 /* policy for the key attributes */
@@ -6984,6 +6986,9 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
 
         if (info->attrs[NL80211_ATTR_MAC])
                 connect.bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);
+        else if (info->attrs[NL80211_ATTR_MAC_HINT])
+                connect.bssid_hint =
+                        nla_data(info->attrs[NL80211_ATTR_MAC_HINT]);
         connect.ssid = nla_data(info->attrs[NL80211_ATTR_SSID]);
         connect.ssid_len = nla_len(info->attrs[NL80211_ATTR_SSID]);
 
@@ -7008,6 +7013,14 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
                 if (!connect.channel ||
                     connect.channel->flags & IEEE80211_CHAN_DISABLED)
                         return -EINVAL;
+        } else if (info->attrs[NL80211_ATTR_WIPHY_FREQ_HINT]) {
+                connect.channel_hint =
+                        ieee80211_get_channel(wiphy,
+                            nla_get_u32(
+                                    info->attrs[NL80211_ATTR_WIPHY_FREQ_HINT]));
+                if (!connect.channel_hint ||
+                    connect.channel_hint->flags & IEEE80211_CHAN_DISABLED)
+                        return -EINVAL;
         }
 
         if (connect.privacy && info->attrs[NL80211_ATTR_KEYS]) {