nl80211/cfg80211: Allow SSID to be specified in new beacon command

This makes it easier for drivers that generate Beacon and Probe Response
frames internally (in firmware most likely) in AP mode.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/nl80211.h

@@ -161,6 +161,9 @@
  * @NL80211_CMD_SET_BEACON: set the beacon on an access point interface
  *	using the %NL80211_ATTR_BEACON_INTERVAL, %NL80211_ATTR_DTIM_PERIOD,
  *	%NL80211_ATTR_BEACON_HEAD and %NL80211_ATTR_BEACON_TAIL attributes.
+ *	Following attributes are provided for drivers that generate full Beacon
+ *	and Probe Response frames internally: %NL80211_ATTR_SSID,
+ *	%NL80211_ATTR_HIDDEN_SSID.
  * @NL80211_CMD_NEW_BEACON: add a new beacon to an access point interface,
  *	parameters are like for %NL80211_CMD_SET_BEACON.
  * @NL80211_CMD_DEL_BEACON: remove the beacon, stop sending it
@@ -1019,6 +1022,10 @@ enum nl80211_commands {
  *	being a list of supported rates as defined by IEEE 802.11 7.3.2.2 but
  *	without the length restriction (at most %NL80211_MAX_SUPP_RATES).
  *
+ * @NL80211_ATTR_HIDDEN_SSID: indicates whether SSID is to be hidden from Beacon
+ *	and Probe Response (when response to wildcard Probe Request); see
+ *	&enum nl80211_hidden_ssid, represented as a u32
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -1224,6 +1231,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_SCAN_SUPP_RATES,
 
+	NL80211_ATTR_HIDDEN_SSID,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -2430,4 +2439,19 @@ enum nl80211_rekey_data {
 	MAX_NL80211_REKEY_DATA = NUM_NL80211_REKEY_DATA - 1
 };
 
+/**
+ * enum nl80211_hidden_ssid - values for %NL80211_ATTR_HIDDEN_SSID
+ * @NL80211_HIDDEN_SSID_NOT_IN_USE: do not hide SSID (i.e., broadcast it in
+ *	Beacon frames)
+ * @NL80211_HIDDEN_SSID_ZERO_LEN: hide SSID by using zero-length SSID element
+ *	in Beacon frames
+ * @NL80211_HIDDEN_SSID_ZERO_CONTENTS: hide SSID by using correct length of SSID
+ *	element in Beacon frames but zero out each byte in the SSID
+ */
+enum nl80211_hidden_ssid {
+	NL80211_HIDDEN_SSID_NOT_IN_USE,
+	NL80211_HIDDEN_SSID_ZERO_LEN,
+	NL80211_HIDDEN_SSID_ZERO_CONTENTS
+};
+
 #endif /* __LINUX_NL80211_H */

include/net/cfg80211.h

@@ -346,11 +346,18 @@ struct survey_info {
  * @dtim_period: DTIM period or zero if not changed
  * @head_len: length of @head
  * @tail_len: length of @tail
+ * @ssid: SSID to be used in the BSS (note: may be %NULL if not provided from
+ *	user space)
+ * @ssid_len: length of @ssid
+ * @hidden_ssid: whether to hide the SSID in Beacon/Probe Response frames
  */
 struct beacon_parameters {
 	u8 *head, *tail;
 	int interval, dtim_period;
 	int head_len, tail_len;
+	const u8 *ssid;
+	size_t ssid_len;
+	enum nl80211_hidden_ssid hidden_ssid;
 };
 
 /**

net/wireless/nl80211.c

@@ -178,6 +178,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
 	[NL80211_ATTR_SCHED_SCAN_INTERVAL] = { .type = NLA_U32 },
 	[NL80211_ATTR_REKEY_DATA] = { .type = NLA_NESTED },
 	[NL80211_ATTR_SCAN_SUPP_RATES] = { .type = NLA_NESTED },
+	[NL80211_ATTR_HIDDEN_SSID] = { .type = NLA_U32 },
 };
 
 /* policy for the key attributes */
@@ -2010,6 +2011,34 @@ static int nl80211_addset_beacon(struct sk_buff *skb, struct genl_info *info)
 		if (err)
 			return err;
 
+		/*
+		 * In theory, some of these attributes could be required for
+		 * NEW_BEACON, but since they were not used when the command was
+		 * originally added, keep them optional for old user space
+		 * programs to work with drivers that do not need the additional
+		 * information.
+		 */
+		if (info->attrs[NL80211_ATTR_SSID]) {
+			params.ssid = nla_data(info->attrs[NL80211_ATTR_SSID]);
+			params.ssid_len =
+				nla_len(info->attrs[NL80211_ATTR_SSID]);
+			if (params.ssid_len == 0 ||
+			    params.ssid_len > IEEE80211_MAX_SSID_LEN)
+				return -EINVAL;
+		}
+
+		if (info->attrs[NL80211_ATTR_HIDDEN_SSID]) {
+			params.hidden_ssid = nla_get_u32(
+				info->attrs[NL80211_ATTR_HIDDEN_SSID]);
+			if (params.hidden_ssid !=
+			    NL80211_HIDDEN_SSID_NOT_IN_USE &&
+			    params.hidden_ssid !=
+			    NL80211_HIDDEN_SSID_ZERO_LEN &&
+			    params.hidden_ssid !=
+			    NL80211_HIDDEN_SSID_ZERO_CONTENTS)
+				return -EINVAL;
+		}
+
 		call = rdev->ops->add_beacon;
 		break;
 	case NL80211_CMD_SET_BEACON: