hostapd: Add eht_bw320_offset configuration option

Introduce a new configuration option, "eht_bw320_offset", which enables
devices to specify a preferred channelization for 320 MHz BSSs when
using automatic channel selection (ACS). This option is applicable only
when the channel is not already decided and the bandwidth is set to 320
MHz.

The value and meaning of the option:
0: auto-detected by ACS
1: 320 MHz-1
2: 320 MHz-2

Co-developed-by: Money Wang <money.wang@mediatek.com>
Signed-off-by: Michael-CY Lee <michael-cy.lee@mediatek.com>

hostapd/config_file.c

@@ -4861,6 +4861,8 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 				   line);
 			return 1;
 		}
+	} else if (os_strcmp(buf, "eht_bw320_offset") == 0) {
+		conf->eht_bw320_offset = atoi(pos);
 #ifdef CONFIG_TESTING_OPTIONS
 	} else if (os_strcmp(buf, "eht_oper_puncturing_override") == 0) {
 		if (get_u16(pos, line, &bss->eht_oper_puncturing_override))

hostapd/hostapd.conf

@@ -1044,6 +1044,15 @@ wmm_ac_vo_acm=0
 # 1 = PE field duration is 20 us
 #eht_default_pe_duration=0
 
+#eht_bw320_offset: For automatic channel selection (ACS) to indicate a preferred
+# 320 MHz channelization in EHT mode.
+# If the channel is decided or the bandwidth is not 320 MHz, this option is
+# meaningless.
+# 0 = auto-detect by hostapd
+# 1 = 320 MHz-1 (channel center frequency 31, 95, 159)
+# 2 = 320 MHz-2 (channel center frequency 63, 127, 191)
+#eht_bw320_offset=0
+
 # Disabled subchannel bitmap (16 bits) as per IEEE P802.11be/3.0,
 # Figure 9-1002c (EHT Operation Information field format). Each bit corresponds
 # to a 20 MHz channel, the lowest bit corresponds to the lowest frequency. A

src/ap/ap_config.c

@@ -299,6 +299,8 @@ struct hostapd_config * hostapd_config_defaults(void)
 	conf->airtime_update_interval = AIRTIME_DEFAULT_UPDATE_INTERVAL;
 #endif /* CONFIG_AIRTIME_POLICY */
 
+	hostapd_set_and_check_bw320_offset(conf, 0);
+
 	return conf;
 }
 
@@ -1560,6 +1562,10 @@ int hostapd_config_check(struct hostapd_config *conf, int full_config)
 			   "Cannot set ieee80211be without ieee80211ax");
 		return -1;
 	}
+
+	if (full_config)
+		hostapd_set_and_check_bw320_offset(conf,
+						   conf->eht_bw320_offset);
 #endif /* CONFIG_IEEE80211BE */
 
 	if (full_config && conf->mbssid && !conf->ieee80211ax) {

src/ap/ap_config.h

@@ -1199,6 +1199,7 @@ struct hostapd_config {
 	u16 punct_bitmap; /* a bitmap of disabled 20 MHz channels */
 	u8 punct_acs_threshold;
 	u8 eht_default_pe_duration;
+	u8 eht_bw320_offset;
 #endif /* CONFIG_IEEE80211BE */
 
 	/* EHT enable/disable config from CHAN_SWITCH */
@@ -1299,6 +1300,43 @@ hostapd_set_oper_centr_freq_seg1_idx(struct hostapd_config *conf,
 	conf->vht_oper_centr_freq_seg1_idx = oper_centr_freq_seg1_idx;
 }
 
+static inline u8
+hostapd_get_bw320_offset(struct hostapd_config *conf)
+{
+#ifdef CONFIG_IEEE80211BE
+	if (conf->ieee80211be && is_6ghz_op_class(conf->op_class) &&
+	    hostapd_get_oper_chwidth(conf) == CONF_OPER_CHWIDTH_320MHZ)
+		return conf->eht_bw320_offset;
+#endif /* CONFIG_IEEE80211BE */
+	return 0;
+}
+
+static inline void
+hostapd_set_and_check_bw320_offset(struct hostapd_config *conf,
+				   u8 bw320_offset)
+{
+#ifdef CONFIG_IEEE80211BE
+	if (conf->ieee80211be && is_6ghz_op_class(conf->op_class) &&
+	    op_class_to_ch_width(conf->op_class) == CONF_OPER_CHWIDTH_320MHZ) {
+		if (conf->channel) {
+			/* If the channel is set, then calculate bw320_offset
+			 * by center frequency segment 0.
+			 */
+			u8 seg0 = hostapd_get_oper_centr_freq_seg0_idx(conf);
+
+			conf->eht_bw320_offset = (seg0 - 31) % 64 ? 2 : 1;
+		} else {
+			/* If the channel is not set, bw320_offset indicates
+			 * preferred offset of 320 MHz.
+			 */
+			conf->eht_bw320_offset = bw320_offset;
+		}
+	} else {
+		conf->eht_bw320_offset = 0;
+	}
+#endif /* CONFIG_IEEE80211BE */
+}
+
 
 int hostapd_mac_comp(const void *a, const void *b);
 struct hostapd_config * hostapd_config_defaults(void);

src/ap/ctrl_iface_ap.c

@@ -830,6 +830,17 @@ int hostapd_ctrl_iface_status(struct hostapd_data *hapd, char *buf,
 		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
+
+		if (is_6ghz_op_class(iface->conf->op_class) &&
+		    hostapd_get_oper_chwidth(iface->conf) ==
+		    CONF_OPER_CHWIDTH_320MHZ) {
+			ret = os_snprintf(buf + len, buflen - len,
+					  "eht_bw320_offset=%d\n",
+					  iface->conf->eht_bw320_offset);
+			if (os_snprintf_error(buflen - len, ret))
+				return len;
+			len += ret;
+		}
 	}
 #endif /* CONFIG_IEEE80211BE */
 

src/ap/drv_callbacks.c

@@ -1170,6 +1170,8 @@ void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
 	hostapd_set_oper_chwidth(hapd->iconf, chwidth);
 	hostapd_set_oper_centr_freq_seg0_idx(hapd->iconf, seg0_idx);
 	hostapd_set_oper_centr_freq_seg1_idx(hapd->iconf, seg1_idx);
+	/* Auto-detect new bw320_offset */
+	hostapd_set_and_check_bw320_offset(hapd->iconf, 0);
 #ifdef CONFIG_IEEE80211BE
 	hapd->iconf->punct_bitmap = punct_bitmap;
 #endif /* CONFIG_IEEE80211BE */