[RFC 2/3] wpa_supplicant: Add 2040 BSS intolerance support in station mode
Jouni Malinen
j
Mon Apr 23 02:01:07 PDT 2012
On Wed, Apr 18, 2012 at 07:14:09PM +0530, Rajkumar Manoharan wrote:
> Add support for HT STA to report 40MHz intolerance to the associated AP.
> A HT station generates a report (2040 BSS coexistence) of channel list
> if it finds a non-HT capable AP or a HT AP which prohibits 40MHz
> transmission (i.e 40MHz intolerant bit is set in HT capabilities IE)
> from the scan results.
This looks SME-specific, so it would be cleaner to keep the
implementation within sme.c until some other uses show up for it. The
below version does that and adds couple of TODO/FIX comments that should
be addressed. The OBSS scan one could be left as a separate one for now,
but the other comments should be addressed for the initial commit (well,
apart from the special Country element cases with operating class
triplets).
diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index da9cf2b..f6e1622 100644
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -1096,6 +1096,12 @@ static int _wpa_supplicant_event_scan_results(struct wpa_supplicant *wpa_s,
selected = wpa_supplicant_pick_network(wpa_s, scan_res, &ssid);
+ /*
+ * TODO: This should be done at the completion of OBSS scan operations
+ * which may or may not be identical to other scans..
+ */
+ sme_proc_40mhz_intolerant(wpa_s);
+
if (selected) {
int skip;
skip = !wpa_supplicant_need_to_roam(wpa_s, selected, ssid,
diff --git a/wpa_supplicant/sme.c b/wpa_supplicant/sme.c
index b366847..f4aa006 100644
--- a/wpa_supplicant/sme.c
+++ b/wpa_supplicant/sme.c
@@ -609,6 +609,160 @@ void sme_deinit(struct wpa_supplicant *wpa_s)
}
+static void sme_send_2040_bss_coex(struct wpa_supplicant *wpa_s,
+ const u8 *chan_list, u8 num_channels)
+{
+ struct ieee80211_2040_bss_coex_ie *bc_ie;
+ struct ieee80211_2040_intol_chan_report *ic_report;
+ struct wpabuf *buf;
+
+ wpa_printf(MSG_DEBUG, "SME: Send 20/40 BSS Coexistence to " MACSTR,
+ MAC2STR(wpa_s->bssid));
+
+ buf = wpabuf_alloc(2 + /* action.category + action_code */
+ sizeof(struct ieee80211_2040_bss_coex_ie) +
+ sizeof(struct ieee80211_2040_intol_chan_report) +
+ num_channels);
+ if (buf == NULL)
+ return;
+
+ wpabuf_put_u8(buf, WLAN_ACTION_PUBLIC);
+ wpabuf_put_u8(buf, WLAN_PA_20_40_BSS_COEX);
+
+ bc_ie = wpabuf_put(buf, sizeof(*bc_ie));
+ bc_ie->element_id = WLAN_EID_20_40_BSS_COEXISTENCE;
+ bc_ie->length = 1;
+ /* TODO: is this flag really supposed to be added uncontionally?
+ * Shouldn't this be added onyl if a trigger event TE-B has been
+ * detected?
+ */
+ bc_ie->coex_info = WLAN_20_40_BSS_COEX_20MHZ_WIDTH_REQ;
+
+ ic_report = wpabuf_put(buf, sizeof(*ic_report));
+ ic_report->element_id = WLAN_EID_20_40_BSS_INTOLERANT;
+ ic_report->length = num_channels + 1;
+ /* FIX: set ic_report->op_class */
+
+ os_memcpy(wpabuf_put(buf, num_channels), chan_list, num_channels);
+
+ if (wpa_drv_send_action(wpa_s, wpa_s->assoc_freq, 0, wpa_s->bssid,
+ wpa_s->own_addr, wpa_s->bssid,
+ wpabuf_head(buf), wpabuf_len(buf), 0) < 0) {
+ wpa_msg(wpa_s, MSG_INFO, "SME: Failed to send 20/40 BSS "
+ "Coexistence frame");
+ }
+
+ wpabuf_free(buf);
+}
+
+
+/**
+ * enum wpas_band - Frequency band
+ * @WPAS_BAND_2GHZ: 2.4 GHz ISM band
+ * @WPAS_BAND_5GHZ: around 5 GHz band (4.9 - 5.7 GHz)
+ */
+enum wpas_band {
+ WPAS_BAND_2GHZ,
+ WPAS_BAND_5GHZ,
+ WPAS_BAND_INVALID
+};
+
+/**
+ * freq_to_channel - Convert frequency into channel info
+ * @channel: Buffer for returning channel number
+ * Returns: Band (2 or 5 GHz)
+ */
+static enum wpas_band freq_to_channel(int freq, u8 *channel)
+{
+ enum wpas_band band = (freq <= 2484) ? WPAS_BAND_2GHZ : WPAS_BAND_5GHZ;
+ u8 chan = 0;
+
+ if (freq >= 2412 && freq <= 2472)
+ chan = (freq - 2407) / 5;
+ else if (freq == 2484)
+ chan = 14;
+ else if (freq >= 5180 && freq <= 5805)
+ chan = (freq - 5000) / 5;
+
+ *channel = chan;
+ return band;
+}
+
+
+void sme_proc_40mhz_intolerant(struct wpa_supplicant *wpa_s)
+{
+ struct wpa_bss *bss;
+ enum wpas_band assoc_band;
+ const u8 *ie;
+ u16 ht_cap;
+ u8 chan_list[P2P_MAX_CHANNELS], channel;
+ u8 num_channels = 0, i;
+
+ if (!wpa_s->current_bss || wpa_s->wpa_state != WPA_COMPLETED)
+ return;
+
+ /* Check whether local driver supports HT40 */
+ if (!wpa_s->hw.modes ||
+ !(wpa_s->hw.modes->ht_capab & HT_CAP_INFO_SUPP_CHANNEL_WIDTH_SET))
+ return;
+
+ /* Check whether AP supports HT40 */
+ ie = wpa_bss_get_ie(wpa_s->current_bss, WLAN_EID_HT_OPERATION);
+ if (!ie || ie[1] < 2 ||
+ !(ie[3] & HT_INFO_HT_PARAM_REC_TRANS_CHNL_WIDTH))
+ return;
+
+ /*
+ * Check whether AP uses regulatory triplet or channel triplet in
+ * country info. Right now the operating class of the BSS channel
+ * width trigger event is "unknown" (IEEE Std 802.11-2012 10.15.12),
+ * based on the assumption that operating class triplet is not used in
+ * beacon frame. If the First Channel Number/Operating Extension
+ * Identifier octet has a positive integer value of 201 or greater,
+ * then its operating class triplet.
+ *
+ * TODO: If Supported Operating Classes element is present in Beacon
+ * frame, have to lookup operating class in Annex E and fill them in
+ * 20/40 coex frame.
+ *
+ * TODO: Is it fine to skip this report if Country element is not
+ * included?
+ */
+ ie = wpa_bss_get_ie(wpa_s->current_bss, WLAN_EID_COUNTRY);
+ if (!ie || ie[1] < 6 || (ie[5] > 201))
+ return;
+
+ assoc_band = freq_to_channel(wpa_s->current_bss->freq, &channel);
+ os_memset(chan_list, 0, sizeof(chan_list));
+
+ dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
+ /* Skip other band bss */
+ if (freq_to_channel(bss->freq, &channel) != assoc_band)
+ continue;
+
+ ie = wpa_bss_get_ie(bss, WLAN_EID_HT_CAP);
+ ht_cap = (ie && (ie[1] == 26)) ? WPA_GET_LE16(ie + 2) : 0;
+
+ /* TODO: Shouldn't TE-B events be counted separately so that
+ * 20 MHz width request flag can be set correctly? */
+ if (!ht_cap || (ht_cap & HT_CAP_INFO_40MHZ_INTOLERANT)) {
+ /* Check whether the channel is already considered */
+ for (i = 0; i < num_channels; i++) {
+ if (channel == chan_list[i])
+ break;
+ }
+ if (i != num_channels)
+ continue;
+
+ chan_list[num_channels++] = channel;
+ }
+ }
+
+ if (num_channels)
+ sme_send_2040_bss_coex(wpa_s, chan_list, num_channels);
+}
+
+
#ifdef CONFIG_IEEE80211W
static const unsigned int sa_query_max_timeout = 1000;
diff --git a/wpa_supplicant/sme.h b/wpa_supplicant/sme.h
index 33530bb..f735832 100644
--- a/wpa_supplicant/sme.h
+++ b/wpa_supplicant/sme.h
@@ -35,6 +35,8 @@ void sme_disassoc_while_authenticating(struct wpa_supplicant *wpa_s,
const u8 *prev_pending_bssid);
void sme_deinit(struct wpa_supplicant *wpa_s);
+void sme_proc_40mhz_intolerant(struct wpa_supplicant *wpa_s);
+
#else /* CONFIG_SME */
static inline void sme_authenticate(struct wpa_supplicant *wpa_s,
@@ -95,6 +97,10 @@ static inline void sme_deinit(struct wpa_supplicant *wpa_s)
{
}
+static inline void sme_proc_40mhz_intolerant(struct wpa_supplicant *wpa_s)
+{
+}
+
#endif /* CONFIG_SME */
#endif /* SME_H */
--
1.7.4.1
--
Jouni Malinen PGP id EFC895FA
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