nl80211: MBSSID and EMA support in AP mode

Add new attributes to configure support for multiple BSSID
and advanced multi-BSSID advertisements (EMA) in AP mode.

- NL80211_ATTR_MBSSID_CONFIG used for per interface configuration.
- NL80211_ATTR_MBSSID_ELEMS used to MBSSID elements for beacons.

Memory for the elements is allocated dynamically. This change frees
the memory in existing functions which call nl80211_parse_beacon(),
a comment is added to indicate the new references to do the same.

Signed-off-by: John Crispin <john@phrozen.org>
Co-developed-by: Aloka Dixit <alokad@codeaurora.org>
Signed-off-by: Aloka Dixit <alokad@codeaurora.org>
Link: https://lore.kernel.org/r/20210916025437.29138-2-alokad@codeaurora.org
[don't leave ERR_PTR hanging around]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 174 insertions, 4 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0f728de36f33..3f37e4d5c5d2 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -437,6 +437,16 @@ sar_policy[NL80211_SAR_ATTR_MAX + 1] = {
 	[NL80211_SAR_ATTR_SPECS] = NLA_POLICY_NESTED_ARRAY(sar_specs_policy),
 };
 
+static const struct nla_policy
+nl80211_mbssid_config_policy[NL80211_MBSSID_CONFIG_ATTR_MAX + 1] = {
+	[NL80211_MBSSID_CONFIG_ATTR_MAX_INTERFACES] = NLA_POLICY_MIN(NLA_U8, 2),
+	[NL80211_MBSSID_CONFIG_ATTR_MAX_EMA_PROFILE_PERIODICITY] =
+						NLA_POLICY_MIN(NLA_U8, 1),
+	[NL80211_MBSSID_CONFIG_ATTR_INDEX] = { .type = NLA_U8 },
+	[NL80211_MBSSID_CONFIG_ATTR_TX_IFINDEX] = { .type = NLA_U32 },
+	[NL80211_MBSSID_CONFIG_ATTR_EMA] = { .type = NLA_FLAG },
+};
+
 static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[0] = { .strict_start_type = NL80211_ATTR_HE_OBSS_PD },
 	[NL80211_ATTR_WIPHY] = { .type = NLA_U32 },
@@ -763,6 +773,9 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_COLOR_CHANGE_COUNT] = { .type = NLA_U8 },
 	[NL80211_ATTR_COLOR_CHANGE_COLOR] = { .type = NLA_U8 },
 	[NL80211_ATTR_COLOR_CHANGE_ELEMS] = NLA_POLICY_NESTED(nl80211_policy),
+	[NL80211_ATTR_MBSSID_CONFIG] =
+			NLA_POLICY_NESTED(nl80211_mbssid_config_policy),
+	[NL80211_ATTR_MBSSID_ELEMS] = { .type = NLA_NESTED },
 };
 
 /* policy for the key attributes */
@@ -2207,6 +2220,35 @@ fail:
 	return -ENOBUFS;
 }
 
+static int nl80211_put_mbssid_support(struct wiphy *wiphy, struct sk_buff *msg)
+{
+	struct nlattr *config;
+
+	if (!wiphy->mbssid_max_interfaces)
+		return 0;
+
+	config = nla_nest_start(msg, NL80211_ATTR_MBSSID_CONFIG);
+	if (!config)
+		return -ENOBUFS;
+
+	if (nla_put_u8(msg, NL80211_MBSSID_CONFIG_ATTR_MAX_INTERFACES,
+		       wiphy->mbssid_max_interfaces))
+		goto fail;
+
+	if (wiphy->ema_max_profile_periodicity &&
+	    nla_put_u8(msg,
+		       NL80211_MBSSID_CONFIG_ATTR_MAX_EMA_PROFILE_PERIODICITY,
+		       wiphy->ema_max_profile_periodicity))
+		goto fail;
+
+	nla_nest_end(msg, config);
+	return 0;
+
+fail:
+	nla_nest_cancel(msg, config);
+	return -ENOBUFS;
+}
+
 struct nl80211_dump_wiphy_state {
 	s64 filter_wiphy;
 	long start;
@@ -2792,6 +2834,9 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		if (nl80211_put_sar_specs(rdev, msg))
 			goto nla_put_failure;
 
+		if (nl80211_put_mbssid_support(&rdev->wiphy, msg))
+			goto nla_put_failure;
+
 		/* done */
 		state->split_start = 0;
 		break;
@@ -4981,6 +5026,96 @@ static int validate_beacon_tx_rate(struct cfg80211_registered_device *rdev,
 	return 0;
 }
 
+static int nl80211_parse_mbssid_config(struct wiphy *wiphy,
+				       struct net_device *dev,
+				       struct nlattr *attrs,
+				       struct cfg80211_mbssid_config *config,
+				       u8 num_elems)
+{
+	struct nlattr *tb[NL80211_MBSSID_CONFIG_ATTR_MAX + 1];
+
+	if (!wiphy->mbssid_max_interfaces)
+		return -EOPNOTSUPP;
+
+	if (nla_parse_nested(tb, NL80211_MBSSID_CONFIG_ATTR_MAX, attrs, NULL,
+			     NULL) ||
+	    !tb[NL80211_MBSSID_CONFIG_ATTR_INDEX])
+		return -EINVAL;
+
+	config->ema = nla_get_flag(tb[NL80211_MBSSID_CONFIG_ATTR_EMA]);
+	if (config->ema) {
+		if (!wiphy->ema_max_profile_periodicity)
+			return -EOPNOTSUPP;
+
+		if (num_elems > wiphy->ema_max_profile_periodicity)
+			return -EINVAL;
+	}
+
+	config->index = nla_get_u8(tb[NL80211_MBSSID_CONFIG_ATTR_INDEX]);
+	if (config->index >= wiphy->mbssid_max_interfaces ||
+	    (!config->index && !num_elems))
+		return -EINVAL;
+
+	if (tb[NL80211_MBSSID_CONFIG_ATTR_TX_IFINDEX]) {
+		u32 tx_ifindex =
+			nla_get_u32(tb[NL80211_MBSSID_CONFIG_ATTR_TX_IFINDEX]);
+
+		if ((!config->index && tx_ifindex != dev->ifindex) ||
+		    (config->index && tx_ifindex == dev->ifindex))
+			return -EINVAL;
+
+		if (tx_ifindex != dev->ifindex) {
+			struct net_device *tx_netdev =
+				dev_get_by_index(wiphy_net(wiphy), tx_ifindex);
+
+			if (!tx_netdev || !tx_netdev->ieee80211_ptr ||
+			    tx_netdev->ieee80211_ptr->wiphy != wiphy ||
+			    tx_netdev->ieee80211_ptr->iftype !=
+							NL80211_IFTYPE_AP) {
+				dev_put(tx_netdev);
+				return -EINVAL;
+			}
+
+			config->tx_wdev = tx_netdev->ieee80211_ptr;
+		} else {
+			config->tx_wdev = dev->ieee80211_ptr;
+		}
+	} else if (!config->index) {
+		config->tx_wdev = dev->ieee80211_ptr;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct cfg80211_mbssid_elems *
+nl80211_parse_mbssid_elems(struct wiphy *wiphy, struct nlattr *attrs)
+{
+	struct nlattr *nl_elems;
+	struct cfg80211_mbssid_elems *elems;
+	int rem_elems;
+	u8 i = 0, num_elems = 0;
+
+	if (!wiphy->mbssid_max_interfaces)
+		return ERR_PTR(-EINVAL);
+
+	nla_for_each_nested(nl_elems, attrs, rem_elems)
+		num_elems++;
+
+	elems = kzalloc(struct_size(elems, elem, num_elems), GFP_KERNEL);
+	if (!elems)
+		return ERR_PTR(-ENOMEM);
+
+	nla_for_each_nested(nl_elems, attrs, rem_elems) {
+		elems->elem[i].data = nla_data(nl_elems);
+		elems->elem[i].len = nla_len(nl_elems);
+		i++;
+	}
+	elems->cnt = num_elems;
+	return elems;
+}
+
 static int nl80211_parse_beacon(struct cfg80211_registered_device *rdev,
 				struct nlattr *attrs[],
 				struct cfg80211_beacon_data *bcn)
@@ -5061,6 +5196,17 @@ static int nl80211_parse_beacon(struct cfg80211_registered_device *rdev,
 		bcn->ftm_responder = -1;
 	}
 
+	if (attrs[NL80211_ATTR_MBSSID_ELEMS]) {
+		struct cfg80211_mbssid_elems *mbssid =
+			nl80211_parse_mbssid_elems(&rdev->wiphy,
+						   attrs[NL80211_ATTR_MBSSID_ELEMS]);
+
+		if (IS_ERR(mbssid))
+			return PTR_ERR(mbssid);
+
+		bcn->mbssid_ies = mbssid;
+	}
+
 	return 0;
 }
 
@@ -5547,6 +5693,17 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 			goto out;
 	}
 
+	if (info->attrs[NL80211_ATTR_MBSSID_CONFIG]) {
+		err = nl80211_parse_mbssid_config(&rdev->wiphy, dev,
+						  info->attrs[NL80211_ATTR_MBSSID_CONFIG],
+						  &params->mbssid_config,
+						  params->beacon.mbssid_ies ?
+							params->beacon.mbssid_ies->cnt :
+							0);
+		if (err)
+			goto out;
+	}
+
 	nl80211_calculate_ap_params(params);
 
 	if (info->attrs[NL80211_ATTR_EXTERNAL_AUTH_SUPPORT])
@@ -5568,6 +5725,11 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 
 out:
 	kfree(params->acl);
+	kfree(params->beacon.mbssid_ies);
+	if (params->mbssid_config.tx_wdev &&
+	    params->mbssid_config.tx_wdev->netdev &&
+	    params->mbssid_config.tx_wdev->netdev != dev)
+		dev_put(params->mbssid_config.tx_wdev->netdev);
 	kfree(params);
 
 	return err;
@@ -5593,12 +5755,14 @@ static int nl80211_set_beacon(struct sk_buff *skb, struct genl_info *info)
 
 	err = nl80211_parse_beacon(rdev, info->attrs, &params);
 	if (err)
-		return err;
+		goto out;
 
 	wdev_lock(wdev);
 	err = rdev_change_beacon(rdev, dev, &params);
 	wdev_unlock(wdev);
 
+out:
+	kfree(params.mbssid_ies);
 	return err;
 }
 
@@ -9275,12 +9439,14 @@ static int nl80211_channel_switch(struct sk_buff *skb, struct genl_info *info)
 
 	err = nl80211_parse_beacon(rdev, info->attrs, &params.beacon_after);
 	if (err)
-		return err;
+		goto free;
 
 	csa_attrs = kcalloc(NL80211_ATTR_MAX + 1, sizeof(*csa_attrs),
 			    GFP_KERNEL);
-	if (!csa_attrs)
-		return -ENOMEM;
+	if (!csa_attrs) {
+		err = -ENOMEM;
+		goto free;
+	}
 
 	err = nla_parse_nested_deprecated(csa_attrs, NL80211_ATTR_MAX,
 					  info->attrs[NL80211_ATTR_CSA_IES],
@@ -9398,6 +9564,8 @@ skip_beacons:
 	wdev_unlock(wdev);
 
 free:
+	kfree(params.beacon_after.mbssid_ies);
+	kfree(params.beacon_csa.mbssid_ies);
 	kfree(csa_attrs);
 	return err;
 }
@@ -14933,6 +15101,8 @@ static int nl80211_color_change(struct sk_buff *skb, struct genl_info *info)
 	wdev_unlock(wdev);
 
 out:
+	kfree(params.beacon_next.mbssid_ies);
+	kfree(params.beacon_color_change.mbssid_ies);
 	kfree(tb);
 	return err;
 }