mac80211/cfg80211: Add BSS configuration options for AP mode

This change adds a new cfg80211 command, NL80211_CMD_SET_BSS, to allow
AP mode BSS parameters to be changed from user space (e.g., hostapd).
The drivers using mac80211 are expected to be modified with separate
changes to use the new BSS info parameter for short slot time in the
bss_info_changed() handler.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 89 insertions, 0 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 6d2ad2bf3ab5..2b19532f4c8a 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1010,6 +1010,42 @@ static int ieee80211_dump_mpath(struct wiphy *wiphy, struct net_device *dev,
 }
 #endif
 
+static int ieee80211_change_bss(struct wiphy *wiphy,
+                                struct net_device *dev,
+                                struct bss_parameters *params)
+{
+        struct ieee80211_local *local = wiphy_priv(wiphy);
+        struct ieee80211_sub_if_data *sdata;
+        u32 changed = 0;
+
+        if (dev == local->mdev)
+                return -EOPNOTSUPP;
+
+        sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+        if (sdata->vif.type != IEEE80211_IF_TYPE_AP)
+                return -EINVAL;
+
+        if (params->use_cts_prot >= 0) {
+                sdata->bss_conf.use_cts_prot = params->use_cts_prot;
+                changed |= BSS_CHANGED_ERP_CTS_PROT;
+        }
+        if (params->use_short_preamble >= 0) {
+                sdata->bss_conf.use_short_preamble =
+                        params->use_short_preamble;
+                changed |= BSS_CHANGED_ERP_PREAMBLE;
+        }
+        if (params->use_short_slot_time >= 0) {
+                sdata->bss_conf.use_short_slot =
+                        params->use_short_slot_time;
+                changed |= BSS_CHANGED_ERP_SLOT;
+        }
+
+        ieee80211_bss_info_change_notify(sdata, changed);
+
+        return 0;
+}
+
 struct cfg80211_ops mac80211_config_ops = {
         .add_virtual_intf = ieee80211_add_iface,
         .del_virtual_intf = ieee80211_del_iface,
@@ -1033,4 +1069,5 @@ struct cfg80211_ops mac80211_config_ops = {
         .get_mpath = ieee80211_get_mpath,
         .dump_mpath = ieee80211_dump_mpath,
 #endif
+        .change_bss = ieee80211_change_bss,
 };
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 59eb2cf42e5f..47542ee01c57 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -87,6 +87,10 @@ static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
         [NL80211_ATTR_MESH_ID] = { .type = NLA_BINARY,
                                 .len = IEEE80211_MAX_MESH_ID_LEN },
         [NL80211_ATTR_MPATH_NEXT_HOP] = { .type = NLA_U32 },
+
+        [NL80211_ATTR_BSS_CTS_PROT] = { .type = NLA_U8 },
+        [NL80211_ATTR_BSS_SHORT_PREAMBLE] = { .type = NLA_U8 },
+        [NL80211_ATTR_BSS_SHORT_SLOT_TIME] = { .type = NLA_U8 },
 };
 
 /* message building helper */
@@ -1525,6 +1529,48 @@ static int nl80211_del_mpath(struct sk_buff *skb, struct genl_info *info)
         return err;
 }
 
+static int nl80211_set_bss(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg80211_registered_device *drv;
+        int err;
+        struct net_device *dev;
+        struct bss_parameters params;
+
+        memset(&params, 0, sizeof(params));
+        /* default to not changing parameters */
+        params.use_cts_prot = -1;
+        params.use_short_preamble = -1;
+        params.use_short_slot_time = -1;
+
+        if (info->attrs[NL80211_ATTR_BSS_CTS_PROT])
+                params.use_cts_prot =
+                    nla_get_u8(info->attrs[NL80211_ATTR_BSS_CTS_PROT]);
+        if (info->attrs[NL80211_ATTR_BSS_SHORT_PREAMBLE])
+                params.use_short_preamble =
+                    nla_get_u8(info->attrs[NL80211_ATTR_BSS_SHORT_PREAMBLE]);
+        if (info->attrs[NL80211_ATTR_BSS_SHORT_SLOT_TIME])
+                params.use_short_slot_time =
+                    nla_get_u8(info->attrs[NL80211_ATTR_BSS_SHORT_SLOT_TIME]);
+
+        err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev);
+        if (err)
+                return err;
+
+        if (!drv->ops->change_bss) {
+                err = -EOPNOTSUPP;
+                goto out;
+        }
+
+        rtnl_lock();
+        err = drv->ops->change_bss(&drv->wiphy, dev, &params);
+        rtnl_unlock();
+
+ out:
+        cfg80211_put_dev(drv);
+        dev_put(dev);
+        return err;
+}
+
 static struct genl_ops nl80211_ops[] = {
         {
                 .cmd = NL80211_CMD_GET_WIPHY,
@@ -1656,6 +1702,12 @@ static struct genl_ops nl80211_ops[] = {
                 .policy = nl80211_policy,
                 .flags = GENL_ADMIN_PERM,
         },
+        {
+                .cmd = NL80211_CMD_SET_BSS,
+                .doit = nl80211_set_bss,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+        },
 };
 
 /* multicast groups */