From 62fa124ce2fb44f722ca26388956cc99f3115ada Mon Sep 17 00:00:00 2001
From: Jouni Malinen <j@w1.fi>
Date: Tue, 17 Nov 2009 19:25:05 +0200
Subject: [PATCH] nl80211/SME: Use reassociation when roaming within the ESS

---
 src/drivers/driver.h              | 8 ++++++++
 src/drivers/driver_nl80211.c      | 7 +++++++
 wpa_supplicant/events.c           | 5 +++++
 wpa_supplicant/sme.c              | 7 +++++++
 wpa_supplicant/wpa_supplicant_i.h | 2 ++
 5 files changed, 29 insertions(+)

diff --git a/src/drivers/driver.h b/src/drivers/driver.h
index 89400cd78..73658475b 100644
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -409,6 +409,14 @@ struct wpa_driver_associate_params {
 	 * still be allowed for key negotiation.
 	 */
 	int drop_unencrypted;
+
+	/**
+	 * prev_bssid - Previously used BSSID in this ESS
+	 *
+	 * When not %NULL, this is a request to use reassociation instead of
+	 * association.
+	 */
+	const u8 *prev_bssid;
 };
 
 /**
diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
index 97348ef29..ac3f4dd12 100644
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -3599,6 +3599,13 @@ static int wpa_driver_nl80211_associate(
 
 	NLA_PUT_FLAG(msg, NL80211_ATTR_CONTROL_PORT);
 
+	if (params->prev_bssid) {
+		wpa_printf(MSG_DEBUG, "  * prev_bssid=" MACSTR,
+			   MAC2STR(params->prev_bssid));
+		NLA_PUT(msg, NL80211_ATTR_PREV_BSSID, ETH_ALEN,
+			params->prev_bssid);
+	}
+
 	ret = send_and_recv_msgs(drv, msg, NULL, NULL);
 	msg = NULL;
 	if (ret) {
diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index 896452db7..5f551808a 100644
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -983,6 +983,11 @@ static void wpa_supplicant_event_assoc(struct wpa_supplicant *wpa_s,
 		}
 	}
 
+#ifdef CONFIG_SME
+	os_memcpy(wpa_s->sme.prev_bssid, bssid, ETH_ALEN);
+	wpa_s->sme.prev_bssid_set = 1;
+#endif /* CONFIG_SME */
+
 	wpa_msg(wpa_s, MSG_INFO, "Associated with " MACSTR, MAC2STR(bssid));
 	if (wpa_s->current_ssid) {
 		/* When using scanning (ap_scan=1), SIM PC/SC interface can be
diff --git a/wpa_supplicant/sme.c b/wpa_supplicant/sme.c
index e148595f1..7b2764c2f 100644
--- a/wpa_supplicant/sme.c
+++ b/wpa_supplicant/sme.c
@@ -59,6 +59,10 @@ void sme_authenticate(struct wpa_supplicant *wpa_s,
 	params.ssid = ie + 2;
 	params.ssid_len = ie[1];
 
+	if (wpa_s->sme.ssid_len != params.ssid_len ||
+	    os_memcmp(wpa_s->sme.ssid, params.ssid, params.ssid_len) != 0)
+		wpa_s->sme.prev_bssid_set = 0;
+
 	wpa_s->sme.freq = params.freq;
 	os_memcpy(wpa_s->sme.ssid, params.ssid, params.ssid_len);
 	wpa_s->sme.ssid_len = params.ssid_len;
@@ -312,6 +316,8 @@ void sme_event_auth(struct wpa_supplicant *wpa_s, union wpa_event_data *data)
 #endif /* CONFIG_IEEE80211R */
 	params.mode = ssid->mode;
 	params.mgmt_frame_protection = wpa_s->sme.mfp;
+	if (wpa_s->sme.prev_bssid_set)
+		params.prev_bssid = wpa_s->sme.prev_bssid;
 
 	wpa_msg(wpa_s, MSG_INFO, "Trying to associate with " MACSTR
 		" (SSID='%s' freq=%d MHz)", MAC2STR(params.bssid),
@@ -378,6 +384,7 @@ void sme_event_assoc_reject(struct wpa_supplicant *wpa_s,
 		wpa_msg(wpa_s, MSG_INFO,
 			"Deauth request to the driver failed");
 	}
+	wpa_s->sme.prev_bssid_set = 0;
 
 	if (wpa_blacklist_add(wpa_s, wpa_s->pending_bssid) == 0) {
 		struct wpa_blacklist *b;
diff --git a/wpa_supplicant/wpa_supplicant_i.h b/wpa_supplicant/wpa_supplicant_i.h
index 193baa34c..7cd242662 100644
--- a/wpa_supplicant/wpa_supplicant_i.h
+++ b/wpa_supplicant/wpa_supplicant_i.h
@@ -407,6 +407,8 @@ struct wpa_supplicant {
 		u8 mobility_domain[2];
 		u8 *ft_ies;
 		size_t ft_ies_len;
+		u8 prev_bssid[ETH_ALEN];
+		int prev_bssid_set;
 	} sme;
 #endif /* CONFIG_SME */