P2P: Remove CCK supported rates when running P2P scan

This allows drivers to disable CCK rates from Probe Request frames.
For nl80211, this is currently applying only to the supported rates
element(s), but this mechanism could be extended to address TX rate
control masking, too, to lessen need for global rate disabling.

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>

src/drivers/driver.h

@@ -264,6 +264,15 @@ struct wpa_driver_scan_params {
 	 * num_filter_ssids - Number of entries in filter_ssids array
 	 */
 	size_t num_filter_ssids;
+
+	/**
+	 * p2p_probe - Used to disable CCK (802.11b) rates for P2P probes
+	 *
+	 * When set, the driver is expected to remove rates 1, 2, 5.5, and 11
+	 * Mbps from the support rates element(s) in the Probe Request frames
+	 * and not to transmit the frames at any of those rates.
+	 */
+	u8 p2p_probe;
 };
 
 /**

src/drivers/driver_nl80211.c

@@ -2438,16 +2438,18 @@ static int wpa_driver_nl80211_scan(void *priv,
 	struct i802_bss *bss = priv;
 	struct wpa_driver_nl80211_data *drv = bss->drv;
 	int ret = 0, timeout;
-	struct nl_msg *msg, *ssids, *freqs;
+	struct nl_msg *msg, *ssids, *freqs, *rates;
 	size_t i;
 
 	msg = nlmsg_alloc();
 	ssids = nlmsg_alloc();
 	freqs = nlmsg_alloc();
-	if (!msg || !ssids || !freqs) {
+	rates = nlmsg_alloc();
+	if (!msg || !ssids || !freqs || !rates) {
 		nlmsg_free(msg);
 		nlmsg_free(ssids);
 		nlmsg_free(freqs);
+		nlmsg_free(rates);
 		return -1;
 	}
 
@@ -2487,6 +2489,18 @@ static int wpa_driver_nl80211_scan(void *priv,
 		nla_put_nested(msg, NL80211_ATTR_SCAN_FREQUENCIES, freqs);
 	}
 
+	if (params->p2p_probe) {
+		/*
+		 * Remove 2.4 GHz rates 1, 2, 5.5, 11 Mbps from supported rates
+		 * by masking out everything else apart from the OFDM rates 6,
+		 * 9, 12, 18, 24, 36, 48, 54 Mbps from non-MCS rates. All 5 GHz
+		 * rates are left enabled.
+		 */
+		NLA_PUT(rates, NL80211_BAND_2GHZ, 8,
+			"\x0c\x12\x18\x24\x30\x48\x60\x6c");
+		nla_put_nested(msg, NL80211_ATTR_SCAN_SUPP_RATES, rates);
+	}
+
 	ret = send_and_recv_msgs(drv, msg, NULL, NULL);
 	msg = NULL;
 	if (ret) {
@@ -2538,6 +2552,7 @@ nla_put_failure:
 	nlmsg_free(ssids);
 	nlmsg_free(msg);
 	nlmsg_free(freqs);
+	nlmsg_free(rates);
 	return ret;
 }
 

wpa_supplicant/p2p_supplicant.c

@@ -120,6 +120,7 @@ static int wpas_p2p_scan(void *ctx, enum p2p_scan_type type, int freq,
 
 	p2p_scan_ie(wpa_s->global->p2p, ies);
 
+	params.p2p_probe = 1;
 	params.extra_ies = wpabuf_head(ies);
 	params.extra_ies_len = wpabuf_len(ies);
 
@@ -2789,6 +2790,7 @@ static void wpas_p2p_join_scan(void *eloop_ctx, void *timeout_ctx)
 
 	p2p_scan_ie(wpa_s->global->p2p, ies);
 
+	params.p2p_probe = 1;
 	params.extra_ies = wpabuf_head(ies);
 	params.extra_ies_len = wpabuf_len(ies);