P2P: Implement wpas_p2p_move_go_csa()

Use channel switch mechanism to move a P2P GO to a new channel,
when required. In order to be able to reconfigure the GO channel,
split wpa_supplicant_conf_ap() function, so the frequency
configuration part can be reused to find additional CSA settings.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>

diff --git a/wpa_supplicant/ap.c b/wpa_supplicant/ap.c
index 7a4f4cf..26ac703 100644 (file)
--- a/wpa_supplicant/ap.c
+++ b/wpa_supplicant/ap.c
@@ -76,10 +76,19 @@ no_vht:
 #endif /* CONFIG_IEEE80211N */
 
 
-void wpa_supplicant_conf_ap_ht(struct wpa_supplicant *wpa_s,
-                              struct wpa_ssid *ssid,
-                              struct hostapd_config *conf)
+int wpa_supplicant_conf_ap_ht(struct wpa_supplicant *wpa_s,
+                             struct wpa_ssid *ssid,
+                             struct hostapd_config *conf)
 {
+       conf->hw_mode = ieee80211_freq_to_chan(ssid->frequency,
+                                              &conf->channel);
+
+       if (conf->hw_mode == NUM_HOSTAPD_MODES) {
+               wpa_printf(MSG_ERROR, "Unsupported AP mode frequency: %d MHz",
+                          ssid->frequency);
+               return -1;
+       }
+
        /* TODO: enable HT40 if driver supports it;
         * drop to 11b if driver does not support 11g */
 
@@ -166,6 +175,8 @@ void wpa_supplicant_conf_ap_ht(struct wpa_supplicant *wpa_s,
                }
        }
 #endif /* CONFIG_IEEE80211N */
+
+       return 0;
 }
 
 
@@ -179,15 +190,8 @@ static int wpa_supplicant_conf_ap(struct wpa_supplicant *wpa_s,
 
        os_strlcpy(bss->iface, wpa_s->ifname, sizeof(bss->iface));
 
-       conf->hw_mode = ieee80211_freq_to_chan(ssid->frequency,
-                                              &conf->channel);
-       if (conf->hw_mode == NUM_HOSTAPD_MODES) {
-               wpa_printf(MSG_ERROR, "Unsupported AP mode frequency: %d MHz",
-                          ssid->frequency);
+       if (wpa_supplicant_conf_ap_ht(wpa_s, ssid, conf))
                return -1;
-       }
-
-       wpa_supplicant_conf_ap_ht(wpa_s, ssid, conf);
 
        if (ieee80211_is_dfs(ssid->frequency) && wpa_s->conf->country[0]) {
                conf->ieee80211h = 1;

diff --git a/wpa_supplicant/ap.h b/wpa_supplicant/ap.h
index 594168c..2b8a1d4 100644 (file)
--- a/wpa_supplicant/ap.h
+++ b/wpa_supplicant/ap.h
@@ -76,9 +76,9 @@ int wpas_ap_wps_add_nfc_pw(struct wpa_supplicant *wpa_s, u16 pw_id,
                           const struct wpabuf *pw, const u8 *pubkey_hash);
 
 struct hostapd_config;
-void wpa_supplicant_conf_ap_ht(struct wpa_supplicant *wpa_s,
-                              struct wpa_ssid *ssid,
-                              struct hostapd_config *conf);
+int wpa_supplicant_conf_ap_ht(struct wpa_supplicant *wpa_s,
+                             struct wpa_ssid *ssid,
+                             struct hostapd_config *conf);
 
 int wpas_ap_stop_ap(struct wpa_supplicant *wpa_s);
 

diff --git a/wpa_supplicant/p2p_supplicant.c b/wpa_supplicant/p2p_supplicant.c
index 78bdd08..1063889 100644 (file)
--- a/wpa_supplicant/p2p_supplicant.c
+++ b/wpa_supplicant/p2p_supplicant.c
@@ -53,6 +53,13 @@
  */
 #define P2P_GO_FREQ_CHANGE_TIME 5
 
+/**
+ * Defines CSA parameters which are used when GO evacuates the no longer valid
+ * channel (and if the driver supports channel switch).
+ */
+#define P2P_GO_CSA_COUNT 7
+#define P2P_GO_CSA_BLOCK_TX 0
+
 #ifndef P2P_MAX_CLIENT_IDLE
 /*
  * How many seconds to try to reconnect to the GO when connection in P2P client
@@ -8473,14 +8480,117 @@ static void wpas_p2p_optimize_listen_channel(struct wpa_supplicant *wpa_s,
 
 static int wpas_p2p_move_go_csa(struct wpa_supplicant *wpa_s)
 {
+       struct hostapd_config *conf;
+       struct p2p_go_neg_results params;
+       struct csa_settings csa_settings;
+       struct wpa_ssid *current_ssid = wpa_s->current_ssid;
+       int old_freq = current_ssid->frequency;
+       int ret;
+       u8 chan;
+
        if (!(wpa_s->drv_flags & WPA_DRIVER_FLAGS_AP_CSA)) {
                wpa_dbg(wpa_s, MSG_DEBUG, "CSA is not enabled");
                return -1;
        }
 
-       /* TODO: Add CSA support */
-       wpa_dbg(wpa_s, MSG_DEBUG, "Moving GO with CSA is not implemented");
-       return -1;
+       /*
+        * TODO: This function may not always work correctly. For example,
+        * when we have a running GO and a BSS on a DFS channel.
+        */
+       if (wpas_p2p_init_go_params(wpa_s, &params, 0, 0, 0, NULL)) {
+               wpa_dbg(wpa_s, MSG_DEBUG,
+                       "P2P CSA: Failed to select new frequency for GO");
+               return -1;
+       }
+
+       if (current_ssid->frequency == params.freq) {
+               wpa_dbg(wpa_s, MSG_DEBUG,
+                       "P2P CSA: Selected same frequency - not moving GO");
+               return 0;
+       }
+
+       conf = hostapd_config_defaults();
+       if (!conf) {
+               wpa_dbg(wpa_s, MSG_DEBUG,
+                       "P2P CSA: Failed to allocate default config");
+               return -1;
+       }
+
+       current_ssid->frequency = params.freq;
+       if (wpa_supplicant_conf_ap_ht(wpa_s, current_ssid, conf)) {
+               wpa_dbg(wpa_s, MSG_DEBUG,
+                       "P2P CSA: Failed to create new GO config");
+               ret = -1;
+               goto out;
+       }
+
+       if (conf->hw_mode != wpa_s->ap_iface->current_mode->mode) {
+               wpa_dbg(wpa_s, MSG_DEBUG,
+                       "P2P CSA: CSA to a different band is not supported");
+               ret = -1;
+               goto out;
+       }
+
+       os_memset(&csa_settings, 0, sizeof(csa_settings));
+       csa_settings.cs_count = P2P_GO_CSA_COUNT;
+       csa_settings.block_tx = P2P_GO_CSA_BLOCK_TX;
+       csa_settings.freq_params.freq = params.freq;
+
+       if (ieee80211_freq_to_channel_ext(params.freq, conf->secondary_channel,
+                                         conf->ieee80211ac,
+                                         &wpa_s->ap_iface->cs_oper_class,
+                                         &chan) == NUM_HOSTAPD_MODES) {
+               wpa_dbg(wpa_s, MSG_DEBUG,
+                       "P2P CSA: Selected invalid frequency");
+               ret = -1;
+               goto out;
+       }
+
+       csa_settings.freq_params.channel = chan;
+       csa_settings.freq_params.sec_channel_offset = conf->secondary_channel;
+       csa_settings.freq_params.ht_enabled = conf->ieee80211n;
+       csa_settings.freq_params.bandwidth = conf->secondary_channel ? 40 : 20;
+
+       if (conf->ieee80211ac) {
+               int freq1 = 0, freq2 = 0;
+
+               if (conf->vht_oper_centr_freq_seg0_idx)
+                       freq1 = ieee80211_chan_to_freq(
+                               NULL, wpa_s->ap_iface->cs_oper_class,
+                               conf->vht_oper_centr_freq_seg0_idx);
+
+               if (conf->vht_oper_centr_freq_seg1_idx)
+                       freq2 = ieee80211_chan_to_freq(
+                               NULL, wpa_s->ap_iface->cs_oper_class,
+                               conf->vht_oper_centr_freq_seg1_idx);
+
+               if (freq1 < 0 || freq2 < 0) {
+                       wpa_dbg(wpa_s, MSG_DEBUG,
+                               "P2P CSA: Selected invalid VHT center freqs");
+                       ret = -1;
+                       goto out;
+               }
+
+               csa_settings.freq_params.vht_enabled = conf->ieee80211ac;
+               csa_settings.freq_params.center_freq1 = freq1;
+               csa_settings.freq_params.center_freq2 = freq2;
+
+               switch (conf->vht_oper_chwidth) {
+               case VHT_CHANWIDTH_80MHZ:
+               case VHT_CHANWIDTH_80P80MHZ:
+                       csa_settings.freq_params.bandwidth = 80;
+                       break;
+               case VHT_CHANWIDTH_160MHZ:
+                       csa_settings.freq_params.bandwidth = 160;
+                       break;
+               }
+       }
+
+       ret = ap_switch_channel(wpa_s, &csa_settings);
+out:
+       current_ssid->frequency = old_freq;
+       hostapd_config_free(conf);
+       return ret;
 }