WNM: Add WNM-Sleep Mode implementation for AP

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>

hostapd/Makefile

@@ -165,6 +165,11 @@ NEED_AES_OMAC1=y
 NEED_AES_UNWRAP=y
 endif
 
+ifdef CONFIG_IEEE80211V
+CFLAGS += -DCONFIG_IEEE80211V
+OBJS += ../src/ap/wnm_ap.o
+endif
+
 ifdef CONFIG_IEEE80211N
 CFLAGS += -DCONFIG_IEEE80211N
 endif

src/ap/drv_callbacks.c

@@ -16,6 +16,7 @@
 #include "crypto/random.h"
 #include "p2p/p2p.h"
 #include "wps/wps.h"
+#include "wnm_ap.h"
 #include "hostapd.h"
 #include "ieee802_11.h"
 #include "sta_info.h"
@@ -502,6 +503,13 @@ static void hostapd_action_rx(struct hostapd_data *hapd,
 					   action->data + 2);
 	}
 #endif /* CONFIG_IEEE80211W */
+#ifdef CONFIG_IEEE80211V
+	if (action->category == WLAN_ACTION_WNM) {
+		wpa_printf(MSG_DEBUG, "%s: WNM_ACTION length %d",
+			   __func__, (int) action->len);
+		ieee802_11_rx_wnm_action_ap(hapd, action);
+	}
+#endif /* CONFIG_IEEE80211V */
 }
 
 

src/ap/wnm_ap.c

@@ -0,0 +1,258 @@
+/*
+ * hostapd - WNM
+ * Copyright (c) 2011-2012, Qualcomm Atheros, Inc.
+ *
+ * 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 "common/ieee802_11_defs.h"
+#include "ap/hostapd.h"
+#include "ap/sta_info.h"
+#include "ap/ap_config.h"
+#include "ap/ap_drv_ops.h"
+#include "ap/wpa_auth.h"
+#include "wnm_ap.h"
+
+#define MAX_TFS_IE_LEN  1024
+
+#ifdef CONFIG_IEEE80211V
+
+/* get the TFS IE from driver */
+static int ieee80211_11_get_tfs_ie(struct hostapd_data *hapd, const u8 *addr,
+				   u8 *buf, u16 *buf_len, enum wnm_oper oper)
+{
+	wpa_printf(MSG_DEBUG, "%s: TFS get operation %d", __func__, oper);
+
+	return hostapd_drv_wnm_oper(hapd, oper, addr, buf, buf_len);
+}
+
+
+/* set the TFS IE to driver */
+static int ieee80211_11_set_tfs_ie(struct hostapd_data *hapd, const u8 *addr,
+				   u8 *buf, u16 *buf_len, enum wnm_oper oper)
+{
+	wpa_printf(MSG_DEBUG, "%s: TFS set operation %d", __func__, oper);
+
+	return hostapd_drv_wnm_oper(hapd, oper, addr, buf, buf_len);
+}
+
+
+/* MLME-SLEEPMODE.response */
+static int ieee802_11_send_wnmsleep_resp(struct hostapd_data *hapd,
+					 const u8 *addr, u8 dialog_token,
+					 u8 action_type, u16 intval)
+{
+	struct ieee80211_mgmt *mgmt;
+	int res;
+	size_t len;
+	size_t gtk_elem_len = 0;
+	size_t igtk_elem_len = 0;
+	struct wnm_sleep_element wnmsleep_ie;
+	u8 *wnmtfs_ie;
+	u8 wnmsleep_ie_len;
+	u16 wnmtfs_ie_len;
+	u8 *pos;
+	struct sta_info *sta;
+	enum wnm_oper tfs_oper = action_type == 0 ? WNM_SLEEP_TFS_RESP_IE_ADD :
+		WNM_SLEEP_TFS_RESP_IE_NONE;
+
+	sta = ap_get_sta(hapd, addr);
+	if (sta == NULL) {
+		wpa_printf(MSG_DEBUG, "%s: station not found", __func__);
+		return -EINVAL;
+	}
+
+	/* WNM-Sleep Mode IE */
+	os_memset(&wnmsleep_ie, 0, sizeof(struct wnm_sleep_element));
+	wnmsleep_ie_len = sizeof(struct wnm_sleep_element);
+	wnmsleep_ie.eid = WLAN_EID_WNMSLEEP;
+	wnmsleep_ie.len = wnmsleep_ie_len - 2;
+	wnmsleep_ie.action_type = action_type;
+	wnmsleep_ie.status = WNM_STATUS_SLEEP_ACCEPT;
+	wnmsleep_ie.intval = intval;
+
+	/* TFS IE(s) */
+	wnmtfs_ie = os_zalloc(MAX_TFS_IE_LEN);
+	if (wnmtfs_ie == NULL)
+		return -1;
+	if (ieee80211_11_get_tfs_ie(hapd, addr, wnmtfs_ie, &wnmtfs_ie_len,
+				    tfs_oper)) {
+		wnmtfs_ie_len = 0;
+		os_free(wnmtfs_ie);
+		wnmtfs_ie = NULL;
+	}
+
+#define MAX_GTK_SUBELEM_LEN 45
+#define MAX_IGTK_SUBELEM_LEN 26
+	mgmt = os_zalloc(sizeof(*mgmt) + wnmsleep_ie_len +
+			 MAX_GTK_SUBELEM_LEN + MAX_IGTK_SUBELEM_LEN);
+	if (mgmt == NULL) {
+		wpa_printf(MSG_DEBUG, "MLME: Failed to allocate buffer for "
+			   "WNM-Sleep Response action frame");
+		return -1;
+	}
+	os_memcpy(mgmt->da, addr, ETH_ALEN);
+	os_memcpy(mgmt->sa, hapd->own_addr, ETH_ALEN);
+	os_memcpy(mgmt->bssid, hapd->own_addr, ETH_ALEN);
+	mgmt->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
+					   WLAN_FC_STYPE_ACTION);
+	mgmt->u.action.category = WLAN_ACTION_WNM;
+	mgmt->u.action.u.wnm_sleep_resp.action = WNM_SLEEP_MODE_RESP;
+	mgmt->u.action.u.wnm_sleep_resp.dialogtoken = dialog_token;
+	pos = (u8 *)mgmt->u.action.u.wnm_sleep_resp.variable;
+	/* add key data if MFP is enabled */
+	if (wpa_auth_uses_mfp(sta->wpa_sm) || action_type != 1){
+		mgmt->u.action.u.wnm_sleep_resp.keydata_len = 0;
+	} else {
+		gtk_elem_len = wpa_wnmsleep_gtk_subelem(sta->wpa_sm, pos);
+		pos += gtk_elem_len;
+		wpa_printf(MSG_DEBUG, "Pass 4, gtk_len = %d",
+			   (int) gtk_elem_len);
+#ifdef CONFIG_IEEE80211W
+		res = wpa_wnmsleep_igtk_subelem(sta->wpa_sm, pos);
+		if (res < 0) {
+			os_free(wnmtfs_ie);
+			os_free(mgmt);
+			return -1;
+		}
+		igtk_elem_len = res;
+		pos += igtk_elem_len;
+		wpa_printf(MSG_DEBUG, "Pass 4 igtk_len = %d",
+			   (int) igtk_elem_len);
+#endif /* CONFIG_IEEE80211W */
+
+		WPA_PUT_LE16((u8 *)
+			     &mgmt->u.action.u.wnm_sleep_resp.keydata_len,
+			     gtk_elem_len + igtk_elem_len);
+	}
+	os_memcpy(pos, &wnmsleep_ie, wnmsleep_ie_len);
+	/* copy TFS IE here */
+	pos += wnmsleep_ie_len;
+	os_memcpy(pos, wnmtfs_ie, wnmtfs_ie_len);
+
+	len = 1 + sizeof(mgmt->u.action.u.wnm_sleep_resp) + gtk_elem_len +
+		igtk_elem_len + wnmsleep_ie_len + wnmtfs_ie_len;
+
+	/* In driver, response frame should be forced to sent when STA is in
+	 * PS mode */
+	res = hostapd_drv_send_action(hapd, hapd->iface->freq, 0,
+				      mgmt->da, &mgmt->u.action.category, len);
+
+	if (!res) {
+		wpa_printf(MSG_DEBUG, "Successfully send WNM-Sleep Response "
+			   "frame");
+
+		/* when entering wnmsleep
+		 * 1. pause the node in driver
+		 * 2. mark the node so that AP won't update GTK/IGTK during
+		 * WNM Sleep
+		 */
+		if (wnmsleep_ie.status == WNM_STATUS_SLEEP_ACCEPT &&
+		    wnmsleep_ie.action_type == 0) {
+			hostapd_drv_wnm_oper(hapd, WNM_SLEEP_ENTER_CONFIRM,
+					     addr, NULL, NULL);
+			wpa_set_wnmsleep(sta->wpa_sm, 1);
+		}
+		/* when exiting wnmsleep
+		 * 1. unmark the node
+		 * 2. start GTK/IGTK update if MFP is not used
+		 * 3. unpause the node in driver
+		 */
+		if (wnmsleep_ie.status == WNM_STATUS_SLEEP_ACCEPT &&
+		    wnmsleep_ie.action_type == 1) {
+			wpa_set_wnmsleep(sta->wpa_sm, 0);
+			hostapd_drv_wnm_oper(hapd, WNM_SLEEP_EXIT_CONFIRM,
+					     addr, NULL, NULL);
+			if (wpa_auth_uses_mfp(sta->wpa_sm) && action_type == 1)
+				wpa_wnmsleep_rekey_gtk(sta->wpa_sm);
+		}
+	} else
+		wpa_printf(MSG_DEBUG, "Fail to send WNM-Sleep Response frame");
+
+#undef MAX_GTK_SUBELEM_LEN
+#undef MAX_IGTK_SUBELEM_LEN
+	os_free(wnmtfs_ie);
+	os_free(mgmt);
+	return res;
+}
+
+
+static void ieee802_11_rx_wnmsleep_req(struct hostapd_data *hapd,
+				       const u8 *addr, const u8 *frm, int len)
+{
+	/*
+	 * Action [1] | Dialog Token [1] | WNM-Sleep Mode IE |
+	 * TFS Response IE
+	 */
+	u8 *pos = (u8 *) frm; /* point to action field */
+	u8 dialog_token = pos[1];
+	struct wnm_sleep_element *wnmsleep_ie = NULL;
+	/* multiple TFS Req IE (assuming consecutive) */
+	u8 *tfsreq_ie_start = NULL;
+	u8 *tfsreq_ie_end = NULL;
+	u16 tfsreq_ie_len = 0;
+
+	pos += 1 + 1;
+	while (pos - frm < len - 1) {
+		u8 ie_len = *(pos+1);
+		if (*pos == WLAN_EID_WNMSLEEP)
+			wnmsleep_ie = (struct wnm_sleep_element *)pos;
+		else if (*pos == WLAN_EID_TFS_REQ) {
+			if (!tfsreq_ie_start)
+				tfsreq_ie_start = pos;
+			tfsreq_ie_end = pos;
+		} else
+			wpa_printf(MSG_DEBUG, "EID %d not recognized", *pos);
+		pos += ie_len + 2;
+	}
+
+	if (!wnmsleep_ie) {
+		wpa_printf(MSG_DEBUG, "No WNM-Sleep IE found");
+		return;
+	}
+
+	if (wnmsleep_ie->action_type == 0 && tfsreq_ie_start &&
+	    tfsreq_ie_end && tfsreq_ie_end - tfsreq_ie_start >= 0) {
+		tfsreq_ie_len = (tfsreq_ie_end + tfsreq_ie_end[1] + 2) -
+			tfsreq_ie_start;
+		wpa_printf(MSG_DEBUG, "TFS Req IE(s) found");
+		/* pass the TFS Req IE(s) to driver for processing */
+		if (ieee80211_11_set_tfs_ie(hapd, addr, tfsreq_ie_start,
+					    &tfsreq_ie_len,
+					    WNM_SLEEP_TFS_REQ_IE_SET))
+			wpa_printf(MSG_DEBUG, "Fail to set TFS Req IE");
+	}
+
+	ieee802_11_send_wnmsleep_resp(hapd, addr, dialog_token,
+				      wnmsleep_ie->action_type,
+				      wnmsleep_ie->intval);
+
+	if (wnmsleep_ie->action_type == 1) {
+		/* clear the tfs after sending the resp frame */
+		ieee80211_11_set_tfs_ie(hapd, addr, tfsreq_ie_start,
+					&tfsreq_ie_len, WNM_SLEEP_TFS_IE_DEL);
+	}
+}
+
+
+void ieee802_11_rx_wnm_action_ap(struct hostapd_data *hapd,
+				 struct rx_action *action)
+{
+	u8 *pos = (u8 *) action->data + 1; /* point to the action field */
+	u8 act = *pos;
+
+	switch (act) {
+	case WNM_SLEEP_MODE_REQ:
+		ieee802_11_rx_wnmsleep_req(hapd, action->sa, action->data + 1,
+					   action->len);
+		break;
+	default:
+		break;
+	}
+}
+
+#endif /* CONFIG_IEEE80211V */

src/ap/wnm_ap.h

@@ -0,0 +1,17 @@
+/*
+ * IEEE 802.11v WNM related functions and structures
+ * Copyright (c) 2011-2012, Qualcomm Atheros, Inc.
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#ifndef WNM_AP_H
+#define WNM_AP_H
+
+struct rx_action;
+
+void ieee802_11_rx_wnm_action_ap(struct hostapd_data *hapd,
+				 struct rx_action *action);
+
+#endif /* WNM_AP_H */

src/ap/wpa_auth.c

@@ -2461,6 +2461,12 @@ static int wpa_group_update_sta(struct wpa_state_machine *sm, void *ctx)
 				"marking station for GTK rekeying");
 	}
 
+#ifdef CONFIG_IEEE80211V
+	/* Do not rekey GTK/IGTK when STA is in wnmsleep */
+	if (sm->is_wnmsleep)
+		return 0;
+#endif /* CONFIG_IEEE80211V */
+
 	sm->group->GKeyDoneStations++;
 	sm->GUpdateStationKeys = TRUE;
 
@@ -2469,6 +2475,132 @@ static int wpa_group_update_sta(struct wpa_state_machine *sm, void *ctx)
 }
 
 
+#ifdef CONFIG_IEEE80211V
+/* update GTK when exiting wnmsleep mode */
+void wpa_wnmsleep_rekey_gtk(struct wpa_state_machine *sm)
+{
+	if (sm->is_wnmsleep)
+		return;
+
+	wpa_group_update_sta(sm, NULL);
+}
+
+
+void wpa_set_wnmsleep(struct wpa_state_machine *sm, int flag)
+{
+	sm->is_wnmsleep = !!flag;
+}
+
+
+int wpa_wnmsleep_gtk_subelem(struct wpa_state_machine *sm, u8 *pos)
+{
+	u8 *subelem;
+	struct wpa_group *gsm = sm->group;
+	size_t subelem_len, pad_len;
+	const u8 *key;
+	size_t key_len;
+	u8 keybuf[32];
+
+	/* GTK subslement */
+	key_len = gsm->GTK_len;
+	if (key_len > sizeof(keybuf))
+		return 0;
+
+	/*
+	 * Pad key for AES Key Wrap if it is not multiple of 8 bytes or is less
+	 * than 16 bytes.
+	 */
+	pad_len = key_len % 8;
+	if (pad_len)
+		pad_len = 8 - pad_len;
+	if (key_len + pad_len < 16)
+		pad_len += 8;
+	if (pad_len) {
+		os_memcpy(keybuf, gsm->GTK[gsm->GN - 1], key_len);
+		os_memset(keybuf + key_len, 0, pad_len);
+		keybuf[key_len] = 0xdd;
+		key_len += pad_len;
+		key = keybuf;
+	} else
+		key = gsm->GTK[gsm->GN - 1];
+
+	/*
+	 * Sub-elem ID[1] | Length[1] | Key Info[2] | Key Length[1] | RSC[8] |
+	 * Key[5..32] | 8 padding.
+	 */
+	subelem_len = 13 + key_len + 8;
+	subelem = os_zalloc(subelem_len);
+	if (subelem == NULL)
+		return 0;
+
+	subelem[0] = WNM_SLEEP_SUBELEM_GTK;
+	subelem[1] = 11 + key_len + 8;
+	/* Key ID in B0-B1 of Key Info */
+	WPA_PUT_LE16(&subelem[2], gsm->GN & 0x03);
+	subelem[4] = gsm->GTK_len;
+	if (wpa_auth_get_seqnum(sm->wpa_auth, NULL, gsm->GN, subelem + 5) != 0)
+	{
+		os_free(subelem);
+		return 0;
+	}
+	if (aes_wrap(sm->PTK.kek, key_len / 8, key, subelem + 13)) {
+		os_free(subelem);
+		return 0;
+	}
+
+	os_memcpy(pos, subelem, subelem_len);
+
+	wpa_hexdump_key(MSG_DEBUG, "Plaintext GTK",
+			gsm->GTK[gsm->GN - 1], gsm->GTK_len);
+	os_free(subelem);
+
+	return subelem_len;
+}
+
+
+#ifdef CONFIG_IEEE80211W
+int wpa_wnmsleep_igtk_subelem(struct wpa_state_machine *sm, u8 *pos)
+{
+	u8 *subelem, *ptr;
+	struct wpa_group *gsm = sm->group;
+	size_t subelem_len;
+
+	/* IGTK subelement
+	 * Sub-elem ID[1] | Length[1] | KeyID[2] | PN[6] |
+	 * Key[16] | 8 padding */
+	subelem_len = 1 + 1 + 2 + 6 + WPA_IGTK_LEN + 8;
+	subelem = os_zalloc(subelem_len);
+	if (subelem == NULL)
+		return 0;
+
+	ptr = subelem;
+	*ptr++ = WNM_SLEEP_SUBELEM_IGTK;
+	*ptr++ = subelem_len - 2;
+	WPA_PUT_LE16(ptr, gsm->GN_igtk);
+	ptr += 2;
+	if (wpa_auth_get_seqnum(sm->wpa_auth, NULL, gsm->GN_igtk, ptr) != 0) {
+		os_free(subelem);
+		return 0;
+	}
+	ptr += 6;
+	if (aes_wrap(sm->PTK.kek, WPA_IGTK_LEN / 8,
+		     gsm->IGTK[gsm->GN_igtk - 4], ptr)) {
+		os_free(subelem);
+		return -1;
+	}
+
+	os_memcpy(pos, subelem, subelem_len);
+
+	wpa_hexdump_key(MSG_DEBUG, "Plaintext IGTK",
+			gsm->IGTK[gsm->GN_igtk - 4], WPA_IGTK_LEN);
+	os_free(subelem);
+
+	return subelem_len;
+}
+#endif /* CONFIG_IEEE80211W */
+#endif /* CONFIG_IEEE80211V */
+
+
 static void wpa_group_setkeys(struct wpa_authenticator *wpa_auth,
 			      struct wpa_group *group)
 {

src/ap/wpa_auth.h

@@ -282,4 +282,13 @@ int wpa_ft_rrb_rx(struct wpa_authenticator *wpa_auth, const u8 *src_addr,
 void wpa_ft_push_pmk_r1(struct wpa_authenticator *wpa_auth, const u8 *addr);
 #endif /* CONFIG_IEEE80211R */
 
+#ifdef CONFIG_IEEE80211V
+void wpa_wnmsleep_rekey_gtk(struct wpa_state_machine *sm);
+void wpa_set_wnmsleep(struct wpa_state_machine *sm, int flag);
+int wpa_wnmsleep_gtk_subelem(struct wpa_state_machine *sm, u8 *pos);
+#ifdef CONFIG_IEEE80211W
+int wpa_wnmsleep_igtk_subelem(struct wpa_state_machine *sm, u8 *pos);
+#endif /* CONFIG_IEEE80211W */
+#endif /* CONFIG_IEEE80211V */
+
 #endif /* WPA_AUTH_H */

src/ap/wpa_auth_i.h

@@ -87,6 +87,9 @@ struct wpa_state_machine {
 	unsigned int ft_completed:1;
 	unsigned int pmk_r1_name_valid:1;
 #endif /* CONFIG_IEEE80211R */
+#ifdef CONFIG_IEEE80211V
+	unsigned int is_wnmsleep:1;
+#endif /* CONFIG_IEEE80211V */
 
 	u8 req_replay_counter[WPA_REPLAY_COUNTER_LEN];
 	int req_replay_counter_used;