OCV: Add function to derive Tx parameters to a specific STA

Use the information elements that were present in the (Re)Association
Request frame to derive the maximum bandwidth the AP will use to
transmit frames to a specific STA. By using this approach, we don't need
to query the kernel for this information, and avoid having to add a
driver API for that.

Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>

src/ap/ieee802_11.h

@@ -168,4 +168,7 @@ int ieee802_11_allowed_address(struct hostapd_data *hapd, const u8 *addr,
 			       char **identity, char **radius_cui,
 			       int is_probe_req);
 
+int get_tx_parameters(struct sta_info *sta, int ap_max_chanwidth,
+		      int ap_seg1_idx, int *bandwidth, int *seg1_idx);
+
 #endif /* IEEE802_11_H */

src/ap/ieee802_11_shared.c

@@ -752,3 +752,71 @@ u8 * hostapd_eid_fils_indic(struct hostapd_data *hapd, u8 *eid, int hessid)
 
 	return pos;
 }
+
+
+#ifdef CONFIG_OCV
+int get_tx_parameters(struct sta_info *sta, int ap_max_chanwidth,
+		      int ap_seg1_idx, int *bandwidth, int *seg1_idx)
+{
+	int ht_40mhz = 0;
+	int vht_80p80 = 0;
+	int requested_bw;
+
+	if (sta->ht_capabilities)
+		ht_40mhz = !!(sta->ht_capabilities->ht_capabilities_info &
+			      HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET);
+
+	if (sta->vht_operation) {
+		struct ieee80211_vht_operation *oper = sta->vht_operation;
+
+		/*
+		 * If a VHT Operation element was present, use it to determine
+		 * the supported channel bandwidth.
+		 */
+		if (oper->vht_op_info_chwidth == 0) {
+			requested_bw = ht_40mhz ? 40 : 20;
+		} else if (oper->vht_op_info_chan_center_freq_seg1_idx == 0) {
+			requested_bw = 80;
+		} else {
+			int diff;
+
+			requested_bw = 160;
+			diff = abs((int)
+				   oper->vht_op_info_chan_center_freq_seg0_idx -
+				   (int)
+				   oper->vht_op_info_chan_center_freq_seg1_idx);
+			vht_80p80 = oper->vht_op_info_chan_center_freq_seg1_idx
+				!= 0 &&	diff > 16;
+		}
+	} else if (sta->vht_capabilities) {
+		struct ieee80211_vht_capabilities *capab;
+		int vht_chanwidth;
+
+		capab = sta->vht_capabilities;
+
+		/*
+		 * If only the VHT Capabilities element is present (e.g., for
+		 * normal clients), use it to determine the supported channel
+		 * bandwidth.
+		 */
+		vht_chanwidth = capab->vht_capabilities_info &
+			VHT_CAP_SUPP_CHAN_WIDTH_MASK;
+		vht_80p80 = capab->vht_capabilities_info &
+			VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ;
+
+		/* TODO: Also take into account Extended NSS BW Support field */
+		requested_bw = vht_chanwidth ? 160 : 80;
+	} else {
+		requested_bw = ht_40mhz ? 40 : 20;
+	}
+
+	*bandwidth = requested_bw < ap_max_chanwidth ?
+		requested_bw : ap_max_chanwidth;
+
+	*seg1_idx = 0;
+	if (ap_seg1_idx && vht_80p80)
+		*seg1_idx = ap_seg1_idx;
+
+	return 0;
+}
+#endif /* CONFIG_OCV */

src/ap/wpa_auth.c

@@ -2637,6 +2637,21 @@ u8 * hostapd_eid_assoc_fils_session(struct wpa_state_machine *sm, u8 *buf,
 #endif /* CONFIG_FILS */
 
 
+#ifdef CONFIG_OCV
+int get_sta_tx_parameters(struct wpa_state_machine *sm, int ap_max_chanwidth,
+			  int ap_seg1_idx, int *bandwidth, int *seg1_idx)
+{
+	struct wpa_authenticator *wpa_auth = sm->wpa_auth;
+
+	if (!wpa_auth->cb->get_sta_tx_params)
+		return -1;
+	return wpa_auth->cb->get_sta_tx_params(wpa_auth->cb_ctx, sm->addr,
+					       ap_max_chanwidth, ap_seg1_idx,
+					       bandwidth, seg1_idx);
+}
+#endif /* CONFIG_OCV */
+
+
 SM_STATE(WPA_PTK, PTKCALCNEGOTIATING)
 {
 	struct wpa_authenticator *wpa_auth = sm->wpa_auth;

src/ap/wpa_auth.h

@@ -270,6 +270,9 @@ struct wpa_auth_callbacks {
 	int (*send_oui)(void *ctx, const u8 *dst, u8 oui_suffix, const u8 *data,
 			size_t data_len);
 	int (*channel_info)(void *ctx, struct wpa_channel_info *ci);
+	int (*get_sta_tx_params)(void *ctx, const u8 *addr,
+				 int ap_max_chanwidth, int ap_seg1_idx,
+				 int *bandwidth, int *seg1_idx);
 #ifdef CONFIG_IEEE80211R_AP
 	struct wpa_state_machine * (*add_sta)(void *ctx, const u8 *sta_addr);
 	int (*set_vlan)(void *ctx, const u8 *sta_addr,
@@ -456,6 +459,9 @@ const u8 *  wpa_fils_validate_fils_session(struct wpa_state_machine *sm,
 int wpa_fils_validate_key_confirm(struct wpa_state_machine *sm, const u8 *ies,
 				  size_t ies_len);
 
+int get_sta_tx_parameters(struct wpa_state_machine *sm, int ap_max_chanwidth,
+			  int ap_seg1_idx, int *bandwidth, int *seg1_idx);
+
 int wpa_auth_write_fte(struct wpa_authenticator *wpa_auth, int use_sha384,
 		       u8 *buf, size_t len);
 void wpa_auth_get_fils_aead_params(struct wpa_state_machine *sm,

src/ap/wpa_auth_glue.c

@@ -27,6 +27,7 @@
 #include "tkip_countermeasures.h"
 #include "ap_drv_ops.h"
 #include "ap_config.h"
+#include "ieee802_11.h"
 #include "pmksa_cache_auth.h"
 #include "wpa_auth.h"
 #include "wpa_auth_glue.h"
@@ -786,6 +787,28 @@ static int hostapd_channel_info(void *ctx, struct wpa_channel_info *ci)
 	return hostapd_drv_channel_info(hapd, ci);
 }
 
+
+#ifdef CONFIG_OCV
+static int hostapd_get_sta_tx_params(void *ctx, const u8 *addr,
+				     int ap_max_chanwidth, int ap_seg1_idx,
+				     int *bandwidth, int *seg1_idx)
+{
+	struct hostapd_data *hapd = ctx;
+	struct sta_info *sta;
+
+	sta = ap_get_sta(hapd, addr);
+	if (!sta) {
+		hostapd_wpa_auth_logger(hapd, addr, LOGGER_INFO,
+					"Failed to get STA info to validate received OCI");
+		return -1;
+	}
+
+	return get_tx_parameters(sta, ap_max_chanwidth, ap_seg1_idx, bandwidth,
+				 seg1_idx);
+}
+#endif /* CONFIG_OCV */
+
+
 #ifdef CONFIG_IEEE80211R_AP
 
 static int hostapd_wpa_auth_send_ft_action(void *ctx, const u8 *dst,
@@ -1200,6 +1223,9 @@ int hostapd_setup_wpa(struct hostapd_data *hapd)
 		.send_ether = hostapd_wpa_auth_send_ether,
 		.send_oui = hostapd_wpa_auth_send_oui,
 		.channel_info = hostapd_channel_info,
+#ifdef CONFIG_OCV
+		.get_sta_tx_params = hostapd_get_sta_tx_params,
+#endif /* CONFIG_OCV */
 #ifdef CONFIG_IEEE80211R_AP
 		.send_ft_action = hostapd_wpa_auth_send_ft_action,
 		.add_sta = hostapd_wpa_auth_add_sta,