Allow channel list to be specified for SCAN command

The new freq=<frequency ranges> parameter to the SCAN command can be
used to request a scan to be performed on the specified set of channels
instead of on all channels. For example, "wpa_cli scan
freq=2400-2500,5180" would scan channels 1-14 and 36. Only the channels
that the driver indicates as enabled and that are within the specified
ranges are included in the request.

Signed-hostap: Jouni Malinen <j@w1.fi>

wpa_supplicant/ctrl_iface.c

@@ -5213,6 +5213,92 @@ static void wpas_ctrl_eapol_response(void *eloop_ctx, void *timeout_ctx)
 }
 
 
+static int set_scan_freqs(struct wpa_supplicant *wpa_s, char *val)
+{
+	struct wpa_freq_range_list ranges;
+	int *freqs = NULL;
+	struct hostapd_hw_modes *mode;
+	u16 i;
+
+	if (wpa_s->hw.modes == NULL)
+		return -1;
+
+	os_memset(&ranges, 0, sizeof(ranges));
+	if (freq_range_list_parse(&ranges, val) < 0)
+		return -1;
+
+	for (i = 0; i < wpa_s->hw.num_modes; i++) {
+		int j;
+
+		mode = &wpa_s->hw.modes[i];
+		for (j = 0; j < mode->num_channels; j++) {
+			unsigned int freq;
+
+			if (mode->channels[j].flag & HOSTAPD_CHAN_DISABLED)
+				continue;
+
+			freq = mode->channels[j].freq;
+			if (!freq_range_list_includes(&ranges, freq))
+				continue;
+
+			int_array_add_unique(&freqs, freq);
+		}
+	}
+
+	os_free(ranges.range);
+	os_free(wpa_s->manual_scan_freqs);
+	wpa_s->manual_scan_freqs = freqs;
+
+	return 0;
+}
+
+
+static void wpas_ctrl_scan(struct wpa_supplicant *wpa_s, char *params,
+			   char *reply, int reply_size, int *reply_len)
+{
+	char *pos;
+
+	if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED) {
+		*reply_len = -1;
+		return;
+	}
+
+	if (params) {
+		if (os_strncasecmp(params, "TYPE=ONLY", 9) == 0)
+			wpa_s->scan_res_handler = scan_only_handler;
+
+		pos = os_strstr(params, "freq=");
+		if (pos && set_scan_freqs(wpa_s, pos + 5) < 0) {
+			*reply_len = -1;
+			return;
+		}
+	} else {
+		os_free(wpa_s->manual_scan_freqs);
+		wpa_s->manual_scan_freqs = NULL;
+		if (wpa_s->scan_res_handler == scan_only_handler)
+			wpa_s->scan_res_handler = NULL;
+	}
+
+	if (!wpa_s->sched_scanning && !wpa_s->scanning &&
+	    ((wpa_s->wpa_state <= WPA_SCANNING) ||
+	     (wpa_s->wpa_state == WPA_COMPLETED))) {
+		wpa_s->normal_scans = 0;
+		wpa_s->scan_req = MANUAL_SCAN_REQ;
+		wpa_s->after_wps = 0;
+		wpa_s->known_wps_freq = 0;
+		wpa_supplicant_req_scan(wpa_s, 0, 0);
+	} else if (wpa_s->sched_scanning) {
+		wpa_printf(MSG_DEBUG, "Stop ongoing sched_scan to allow requested full scan to proceed");
+		wpa_supplicant_cancel_sched_scan(wpa_s);
+		wpa_s->scan_req = MANUAL_SCAN_REQ;
+		wpa_supplicant_req_scan(wpa_s, 0, 0);
+	} else {
+		wpa_printf(MSG_DEBUG, "Ongoing scan action - reject new request");
+		*reply_len = os_snprintf(reply, reply_size, "FAIL-BUSY\n");
+	}
+}
+
+
 char * wpa_supplicant_ctrl_iface_process(struct wpa_supplicant *wpa_s,
 					 char *buf, size_t *resp_len)
 {
@@ -5591,36 +5677,10 @@ char * wpa_supplicant_ctrl_iface_process(struct wpa_supplicant *wpa_s,
 		wpa_supplicant_cancel_scan(wpa_s);
 		wpa_supplicant_deauthenticate(wpa_s,
 					      WLAN_REASON_DEAUTH_LEAVING);
-	} else if (os_strcmp(buf, "SCAN") == 0 ||
-		   os_strncmp(buf, "SCAN ", 5) == 0) {
-		if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED)
-			reply_len = -1;
-		else {
-			if (os_strlen(buf) > 4 &&
-			    os_strncasecmp(buf + 5, "TYPE=ONLY", 9) == 0)
-				wpa_s->scan_res_handler = scan_only_handler;
-			if (!wpa_s->sched_scanning && !wpa_s->scanning &&
-			    ((wpa_s->wpa_state <= WPA_SCANNING) ||
-			     (wpa_s->wpa_state == WPA_COMPLETED))) {
-				wpa_s->normal_scans = 0;
-				wpa_s->scan_req = MANUAL_SCAN_REQ;
-				wpa_s->after_wps = 0;
-				wpa_s->known_wps_freq = 0;
-				wpa_supplicant_req_scan(wpa_s, 0, 0);
-			} else if (wpa_s->sched_scanning) {
-				wpa_printf(MSG_DEBUG, "Stop ongoing "
-					   "sched_scan to allow requested "
-					   "full scan to proceed");
-				wpa_supplicant_cancel_sched_scan(wpa_s);
-				wpa_s->scan_req = MANUAL_SCAN_REQ;
-				wpa_supplicant_req_scan(wpa_s, 0, 0);
-			} else {
-				wpa_printf(MSG_DEBUG, "Ongoing scan action - "
-					   "reject new request");
-				reply_len = os_snprintf(reply, reply_size,
-							"FAIL-BUSY\n");
-			}
-		}
+	} else if (os_strcmp(buf, "SCAN") == 0) {
+		wpas_ctrl_scan(wpa_s, NULL, reply, reply_size, &reply_len);
+	} else if (os_strncmp(buf, "SCAN ", 5) == 0) {
+		wpas_ctrl_scan(wpa_s, buf + 5, reply, reply_size, &reply_len);
 	} else if (os_strcmp(buf, "SCAN_RESULTS") == 0) {
 		reply_len = wpa_supplicant_ctrl_iface_scan_results(
 			wpa_s, reply, reply_size);

wpa_supplicant/scan.c

@@ -711,6 +711,13 @@ ssid_list_set:
 	wpa_supplicant_optimize_freqs(wpa_s, &params);
 	extra_ie = wpa_supplicant_extra_ies(wpa_s);
 
+	if (wpa_s->last_scan_req == MANUAL_SCAN_REQ && params.freqs == NULL &&
+	    wpa_s->manual_scan_freqs) {
+		wpa_dbg(wpa_s, MSG_DEBUG, "Limit manual scan to specified channels");
+		params.freqs = wpa_s->manual_scan_freqs;
+		wpa_s->manual_scan_freqs = NULL;
+	}
+
 	if (params.freqs == NULL && wpa_s->next_scan_freqs) {
 		wpa_dbg(wpa_s, MSG_DEBUG, "Optimize scan based on previously "
 			"generated frequency list");
@@ -799,6 +806,13 @@ scan:
 
 	ret = wpa_supplicant_trigger_scan(wpa_s, scan_params);
 
+	if (ret && wpa_s->last_scan_req == MANUAL_SCAN_REQ && params.freqs &&
+	    !wpa_s->manual_scan_freqs) {
+		/* Restore manual_scan_freqs for the next attempt */
+		wpa_s->manual_scan_freqs = params.freqs;
+		params.freqs = NULL;
+	}
+
 	wpabuf_free(extra_ie);
 	os_free(params.freqs);
 	os_free(params.filter_ssids);

wpa_supplicant/wpa_supplicant.c

@@ -459,6 +459,9 @@ static void wpa_supplicant_cleanup(struct wpa_supplicant *wpa_s)
 	os_free(wpa_s->next_scan_freqs);
 	wpa_s->next_scan_freqs = NULL;
 
+	os_free(wpa_s->manual_scan_freqs);
+	wpa_s->manual_scan_freqs = NULL;
+
 	gas_query_deinit(wpa_s->gas);
 	wpa_s->gas = NULL;
 

wpa_supplicant/wpa_supplicant_i.h

@@ -482,6 +482,7 @@ struct wpa_supplicant {
 	struct os_reltime scan_trigger_time;
 	int scan_runs; /* number of scan runs since WPS was started */
 	int *next_scan_freqs;
+	int *manual_scan_freqs;
 	int scan_interval; /* time in sec between scans to find suitable AP */
 	int normal_scans; /* normal scans run before sched_scan */
 	int scan_for_connection; /* whether the scan request was triggered for