MBO: Parse non-preferred channel list on the AP

This adds parsing of non-preferred channel list on an MBO AP. The
information in (Re)Association Request and WNM Notification Request
frames is parsed to get the initial value and updates from each
associated MBO STA. The parsed information is available through the STA
control interface command non_pref_chan[i] rows.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/ap/mbo_ap.c

@@ -16,10 +16,75 @@
 #include "mbo_ap.h"
 
 
+void mbo_ap_sta_free(struct sta_info *sta)
+{
+	struct mbo_non_pref_chan_info *info, *prev;
+
+	info = sta->non_pref_chan;
+	sta->non_pref_chan = NULL;
+	while (info) {
+		prev = info;
+		info = info->next;
+		os_free(prev);
+	}
+}
+
+
+static void mbo_ap_parse_non_pref_chan(struct sta_info *sta,
+				       const u8 *buf, size_t len)
+{
+	struct mbo_non_pref_chan_info *info, *tmp;
+	char channels[200], *pos, *end;
+	size_t num_chan, i;
+	int ret;
+
+	if (len <= 4)
+		return; /* Not enough room for any channels */
+
+	num_chan = len - 4;
+	info = os_zalloc(sizeof(*info) + num_chan);
+	if (!info)
+		return;
+	info->op_class = buf[0];
+	info->pref = buf[len - 3];
+	info->reason_code = buf[len - 2];
+	info->reason_detail = buf[len - 1];
+	info->num_channels = num_chan;
+	buf++;
+	os_memcpy(info->channels, buf, num_chan);
+	if (!sta->non_pref_chan) {
+		sta->non_pref_chan = info;
+	} else {
+		tmp = sta->non_pref_chan;
+		while (tmp->next)
+			tmp = tmp->next;
+		tmp->next = info;
+	}
+
+	pos = channels;
+	end = pos + sizeof(channels);
+	*pos = '\0';
+	for (i = 0; i < num_chan; i++) {
+		ret = os_snprintf(pos, end - pos, "%s%u",
+				  i == 0 ? "" : " ", buf[i]);
+		if (os_snprintf_error(end - pos, ret)) {
+			*pos = '\0';
+			break;
+		}
+		pos += ret;
+	}
+
+	wpa_printf(MSG_DEBUG, "MBO: STA " MACSTR
+		   " non-preferred channel list (op class %u, pref %u, reason code %u, reason detail %u, channels %s)",
+		   MAC2STR(sta->addr), info->op_class, info->pref,
+		   info->reason_code, info->reason_detail, channels);
+}
+
+
 void mbo_ap_check_sta_assoc(struct hostapd_data *hapd, struct sta_info *sta,
 			    struct ieee802_11_elems *elems)
 {
-	const u8 *pos, *attr;
+	const u8 *pos, *attr, *end;
 	size_t len;
 
 	if (!hapd->conf->mbo_enabled || !elems->mbo)
@@ -32,20 +97,72 @@ void mbo_ap_check_sta_assoc(struct hostapd_data *hapd, struct sta_info *sta,
 	attr = get_ie(pos, len, MBO_ATTR_ID_CELL_DATA_CAPA);
 	if (attr && attr[1] >= 1)
 		sta->cell_capa = attr[2];
+
+	mbo_ap_sta_free(sta);
+	end = pos + len;
+	while (end - pos > 1) {
+		u8 ie_len = pos[1];
+
+		if (2 + ie_len > end - pos)
+			break;
+
+		if (pos[0] == MBO_ATTR_ID_NON_PREF_CHAN_REPORT)
+			mbo_ap_parse_non_pref_chan(sta, pos + 2, ie_len);
+		pos += 2 + pos[1];
+	}
 }
 
 
 int mbo_ap_get_info(struct sta_info *sta, char *buf, size_t buflen)
 {
+	char *pos = buf, *end = buf + buflen;
 	int ret;
+	struct mbo_non_pref_chan_info *info;
+	u8 i;
+	unsigned int count = 0;
 
 	if (!sta->cell_capa)
 		return 0;
 
-	ret = os_snprintf(buf, buflen, "mbo_cell_capa=%u\n", sta->cell_capa);
-	if (os_snprintf_error(buflen, ret))
-		return 0;
-	return ret;
+	ret = os_snprintf(pos, end - pos, "mbo_cell_capa=%u\n", sta->cell_capa);
+	if (os_snprintf_error(end - pos, ret))
+		return pos - buf;
+	pos += ret;
+
+	for (info = sta->non_pref_chan; info; info = info->next) {
+		char *pos2 = pos;
+
+		ret = os_snprintf(pos2, end - pos2,
+				  "non_pref_chan[%u]=%u:%u:%u:%u:",
+				  count, info->op_class, info->pref,
+				  info->reason_code, info->reason_detail);
+		count++;
+		if (os_snprintf_error(end - pos2, ret))
+			break;
+		pos2 += ret;
+
+		for (i = 0; i < info->num_channels; i++) {
+			ret = os_snprintf(pos2, end - pos2, "%u%s",
+					  info->channels[i],
+					  i + 1 < info->num_channels ?
+					  "," : "");
+			if (os_snprintf_error(end - pos2, ret)) {
+				pos2 = NULL;
+				break;
+			}
+			pos2 += ret;
+		}
+
+		if (!pos2)
+			break;
+		ret = os_snprintf(pos2, end - pos2, "\n");
+		if (os_snprintf_error(end - pos2, ret))
+			break;
+		pos2 += ret;
+		pos = pos2;
+	}
+
+	return pos - buf;
 }
 
 
@@ -62,9 +179,21 @@ static void mbo_ap_wnm_notif_req_cell_capa(struct sta_info *sta,
 
 
 static void mbo_ap_wnm_notif_req_elem(struct sta_info *sta, u8 type,
-				      const u8 *buf, size_t len)
+				      const u8 *buf, size_t len,
+				      int *first_non_pref_chan)
 {
 	switch (type) {
+	case WFA_WNM_NOTIF_SUBELEM_NON_PREF_CHAN_REPORT:
+		if (*first_non_pref_chan) {
+			/*
+			 * Need to free the previously stored entries now to
+			 * allow the update to replace all entries.
+			 */
+			*first_non_pref_chan = 0;
+			mbo_ap_sta_free(sta);
+		}
+		mbo_ap_parse_non_pref_chan(sta, buf, len);
+		break;
 	case WFA_WNM_NOTIF_SUBELEM_CELL_DATA_CAPA:
 		mbo_ap_wnm_notif_req_cell_capa(sta, buf, len);
 		break;
@@ -83,6 +212,7 @@ void mbo_ap_wnm_notification_req(struct hostapd_data *hapd, const u8 *addr,
 	const u8 *pos, *end;
 	u8 ie_len;
 	struct sta_info *sta;
+	int first_non_pref_chan = 1;
 
 	if (!hapd->conf->mbo_enabled)
 		return;
@@ -103,7 +233,8 @@ void mbo_ap_wnm_notification_req(struct hostapd_data *hapd, const u8 *addr,
 		if (pos[0] == WLAN_EID_VENDOR_SPECIFIC &&
 		    ie_len >= 4 && WPA_GET_BE24(pos + 2) == OUI_WFA)
 			mbo_ap_wnm_notif_req_elem(sta, pos[5],
-						  pos + 6, ie_len - 4);
+						  pos + 6, ie_len - 4,
+						  &first_non_pref_chan);
 		else
 			wpa_printf(MSG_DEBUG,
 				   "MBO: Ignore unknown WNM Notification element %u (len=%u)",

src/ap/mbo_ap.h

@@ -20,6 +20,7 @@ void mbo_ap_check_sta_assoc(struct hostapd_data *hapd, struct sta_info *sta,
 int mbo_ap_get_info(struct sta_info *sta, char *buf, size_t buflen);
 void mbo_ap_wnm_notification_req(struct hostapd_data *hapd, const u8 *addr,
 				 const u8 *buf, size_t len);
+void mbo_ap_sta_free(struct sta_info *sta);
 
 #else /* CONFIG_MBO */
 
@@ -41,6 +42,10 @@ static inline void mbo_ap_wnm_notification_req(struct hostapd_data *hapd,
 {
 }
 
+static inline void mbo_ap_sta_free(struct sta_info *sta)
+{
+}
+
 #endif /* CONFIG_MBO */
 
 #endif /* MBO_AP_H */

src/ap/sta_info.c

@@ -32,6 +32,7 @@
 #include "ap_drv_ops.h"
 #include "gas_serv.h"
 #include "wnm_ap.h"
+#include "mbo_ap.h"
 #include "ndisc_snoop.h"
 #include "sta_info.h"
 #include "vlan.h"
@@ -326,6 +327,8 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 	os_free(sta->sae);
 #endif /* CONFIG_SAE */
 
+	mbo_ap_sta_free(sta);
+
 	os_free(sta);
 }
 

src/ap/sta_info.h

@@ -46,6 +46,16 @@
 #define WLAN_SUPP_RATES_MAX 32
 
 
+struct mbo_non_pref_chan_info {
+	struct mbo_non_pref_chan_info *next;
+	u8 op_class;
+	u8 pref;
+	u8 reason_code;
+	u8 reason_detail;
+	u8 num_channels;
+	u8 channels[];
+};
+
 struct sta_info {
 	struct sta_info *next; /* next entry in sta list */
 	struct sta_info *hnext; /* next entry in hash table list */
@@ -178,6 +188,7 @@ struct sta_info {
 #ifdef CONFIG_MBO
 	u8 cell_capa; /* 0 = unknown (not an MBO STA); otherwise,
 		       * enum mbo_cellular_capa values */
+	struct mbo_non_pref_chan_info *non_pref_chan;
 #endif /* CONFIG_MBO */
 };