OCV: Add utility functions to insert OCI elements

This commit adds utility functions to insert various encoding of the OCI
element.

Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>

hostapd/Android.mk

@@ -237,6 +237,7 @@ endif
 
 ifdef CONFIG_OCV
 L_CFLAGS += -DCONFIG_OCV
+OBJS += src/common/ocv.c
 CONFIG_IEEE80211W=y
 endif
 

hostapd/Makefile

@@ -280,6 +280,7 @@ endif
 
 ifdef CONFIG_OCV
 CFLAGS += -DCONFIG_OCV
+OBJS += ../src/common/ocv.o
 CONFIG_IEEE80211W=y
 endif
 

src/common/ocv.c

@@ -0,0 +1,95 @@
+/*
+ * Operating Channel Validation (OCV)
+ * Copyright (c) 2018, Mathy Vanhoef
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "utils/includes.h"
+#include "utils/common.h"
+#include "drivers/driver.h"
+#include "common/ieee802_11_common.h"
+#include "ocv.h"
+
+/**
+ * Caller of OCV functionality may use various debug output functions, so store
+ * the error here and let the caller use an appropriate debug output function.
+ */
+char ocv_errorstr[256];
+
+
+int ocv_derive_all_parameters(struct oci_info *oci)
+{
+	const struct oper_class_map *op_class_map;
+
+	oci->freq = ieee80211_chan_to_freq(NULL, oci->op_class, oci->channel);
+	if (oci->freq < 0) {
+		wpa_printf(MSG_INFO,
+			   "Error interpreting OCI: unrecognized opclass/channel pair (%d/%d)",
+			   oci->op_class, oci->channel);
+		return -1;
+	}
+
+	op_class_map = get_oper_class(NULL, oci->op_class);
+	if (!op_class_map) {
+		wpa_printf(MSG_INFO,
+			   "Error interpreting OCI: Unrecognized opclass (%d)",
+			   oci->op_class);
+		return -1;
+	}
+
+	oci->chanwidth = oper_class_bw_to_int(op_class_map);
+	oci->sec_channel = 0;
+	if (op_class_map->bw == BW40PLUS)
+		oci->sec_channel = 1;
+	else if (op_class_map->bw == BW40MINUS)
+		oci->sec_channel = -1;
+
+	return 0;
+}
+
+
+int ocv_insert_oci(struct wpa_channel_info *ci, u8 **argpos)
+{
+	u8 op_class, channel;
+	u8 *pos = *argpos;
+
+	if (ieee80211_chaninfo_to_channel(ci->frequency, ci->chanwidth,
+					  ci->sec_channel,
+					  &op_class, &channel) < 0) {
+		wpa_printf(MSG_WARNING,
+			   "Cannot determine operating class and channel for OCI element");
+		return -1;
+	}
+
+	*pos++ = op_class;
+	*pos++ = channel;
+	*pos++ = ci->seg1_idx;
+
+	*argpos = pos;
+	return 0;
+}
+
+
+int ocv_insert_oci_kde(struct wpa_channel_info *ci, u8 **argpos)
+{
+	u8 *pos = *argpos;
+
+	*pos++ = WLAN_EID_VENDOR_SPECIFIC;
+	*pos++ = RSN_SELECTOR_LEN + 3;
+	RSN_SELECTOR_PUT(pos, RSN_KEY_DATA_OCI);
+	pos += RSN_SELECTOR_LEN;
+
+	*argpos = pos;
+	return ocv_insert_oci(ci, argpos);
+}
+
+
+int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *pos)
+{
+	*pos++ = WLAN_EID_EXTENSION;
+	*pos++ = 1 + OCV_OCI_LEN;
+	*pos++ = WLAN_EID_EXT_OCV_OCI;
+	return ocv_insert_oci(ci, &pos);
+}

src/common/ocv.h

@@ -0,0 +1,37 @@
+/*
+ * Operating Channel Validation (OCV)
+ * Copyright (c) 2018, Mathy Vanhoef
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#ifndef OCV_H
+#define OCV_H
+
+struct wpa_channel_info;
+
+struct oci_info {
+	/* Values in the OCI element */
+	u8 op_class;
+	u8 channel;
+	u8 seg1_idx;
+
+	/* Derived values for easier verification */
+	int freq;
+	int sec_channel;
+	int chanwidth;
+};
+
+#define OCV_OCI_LEN		3
+#define OCV_OCI_EXTENDED_LEN	(3 + OCV_OCI_LEN)
+#define OCV_OCI_KDE_LEN		(2 + RSN_SELECTOR_LEN + OCV_OCI_LEN)
+
+extern char ocv_errorstr[256];
+
+int ocv_derive_all_parameters(struct oci_info *oci);
+int ocv_insert_oci(struct wpa_channel_info *ci, u8 **argpos);
+int ocv_insert_oci_kde(struct wpa_channel_info *ci, u8 **argpos);
+int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *pos);
+
+#endif /* OCV_H */

wpa_supplicant/Android.mk

@@ -209,6 +209,7 @@ endif
 
 ifdef CONFIG_OCV
 L_CFLAGS += -DCONFIG_OCV
+OBJS += src/common/ocv.c
 CONFIG_IEEE80211W=y
 endif
 

wpa_supplicant/Makefile

@@ -242,6 +242,7 @@ endif
 
 ifdef CONFIG_OCV
 CFLAGS += -DCONFIG_OCV
+OBJS += ../src/common/ocv.o
 CONFIG_IEEE80211W=y
 endif