From 59b416c7339b342ee6954646cfe861c3f86617e5 Mon Sep 17 00:00:00 2001
From: Jouni Malinen <jouni@qca.qualcomm.com>
Date: Thu, 19 Feb 2015 16:35:39 +0200
Subject: [PATCH] Add optional reassoc-to-same-BSS optimization

The new reassoc_same_bss_optim=1 configuration parameter can now be used
to request wpa_supplicant to bypass the unnecessary Authentication frame
exchange when reassociating back to the same BSS with which the device
is already associated. This functionality is disabled by default since
it may cause undesired interoperability issues with some APs.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
---
 wpa_supplicant/config.c      |  1 +
 wpa_supplicant/config.h      |  5 +++++
 wpa_supplicant/config_file.c |  4 ++++
 wpa_supplicant/sme.c         | 16 ++++++++++++++--
 4 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/wpa_supplicant/config.c b/wpa_supplicant/config.c
index ea633a61a..6c67f9f2e 100644
--- a/wpa_supplicant/config.c
+++ b/wpa_supplicant/config.c
@@ -4185,6 +4185,7 @@ static const struct global_parse_data global_fields[] = {
 	{ INT(preassoc_mac_addr), 0 },
 	{ INT(key_mgmt_offload), 0},
 	{ INT(passive_scan), 0 },
+	{ INT(reassoc_same_bss_optim), 0 },
 };
 
 #undef FUNC
diff --git a/wpa_supplicant/config.h b/wpa_supplicant/config.h
index 2e5499402..afae78df8 100644
--- a/wpa_supplicant/config.h
+++ b/wpa_supplicant/config.h
@@ -1149,6 +1149,11 @@ struct wpa_config {
 	 * (scan_ssid=1) or P2P device discovery.
 	 */
 	int passive_scan;
+
+	/**
+	 * reassoc_same_bss_optim - Whether to optimize reassoc-to-same-BSS
+	 */
+	int reassoc_same_bss_optim;
 };
 
 
diff --git a/wpa_supplicant/config_file.c b/wpa_supplicant/config_file.c
index 66d170c30..ecc57372a 100644
--- a/wpa_supplicant/config_file.c
+++ b/wpa_supplicant/config_file.c
@@ -1233,6 +1233,10 @@ static void wpa_config_write_global(FILE *f, struct wpa_config *config)
 
 	if (config->passive_scan)
 		fprintf(f, "passive_scan=%d\n", config->passive_scan);
+
+	if (config->reassoc_same_bss_optim)
+		fprintf(f, "reassoc_same_bss_optim=%d\n",
+			config->reassoc_same_bss_optim);
 }
 
 #endif /* CONFIG_NO_CONFIG_WRITE */
diff --git a/wpa_supplicant/sme.c b/wpa_supplicant/sme.c
index 6c0570722..178811371 100644
--- a/wpa_supplicant/sme.c
+++ b/wpa_supplicant/sme.c
@@ -207,6 +207,7 @@ static void sme_send_authentication(struct wpa_supplicant *wpa_s,
 	struct wpabuf *resp = NULL;
 	u8 ext_capab[18];
 	int ext_capab_len;
+	int skip_auth;
 
 	if (bss == NULL) {
 		wpa_msg(wpa_s, MSG_ERROR, "SME: No scan result available for "
@@ -215,6 +216,8 @@ static void sme_send_authentication(struct wpa_supplicant *wpa_s,
 		return;
 	}
 
+	skip_auth = wpa_s->conf->reassoc_same_bss_optim &&
+		wpa_s->reassoc_same_bss;
 	wpa_s->current_bss = bss;
 
 	os_memset(&params, 0, sizeof(params));
@@ -465,7 +468,7 @@ static void sme_send_authentication(struct wpa_supplicant *wpa_s,
 	sme_auth_handle_rrm(wpa_s, bss);
 
 #ifdef CONFIG_SAE
-	if (params.auth_alg == WPA_AUTH_ALG_SAE &&
+	if (!skip_auth && params.auth_alg == WPA_AUTH_ALG_SAE &&
 	    pmksa_cache_set_current(wpa_s->wpa, NULL, bss->bssid, ssid, 0) == 0)
 	{
 		wpa_dbg(wpa_s, MSG_DEBUG,
@@ -474,7 +477,7 @@ static void sme_send_authentication(struct wpa_supplicant *wpa_s,
 		wpa_s->sme.sae_pmksa_caching = 1;
 	}
 
-	if (params.auth_alg == WPA_AUTH_ALG_SAE) {
+	if (!skip_auth && params.auth_alg == WPA_AUTH_ALG_SAE) {
 		if (start)
 			resp = sme_auth_build_sae_commit(wpa_s, ssid,
 							 bss->bssid);
@@ -532,6 +535,15 @@ static void sme_send_authentication(struct wpa_supplicant *wpa_s,
 	}
 #endif /* CONFIG_P2P */
 
+	if (skip_auth) {
+		wpa_msg(wpa_s, MSG_DEBUG,
+			"SME: Skip authentication step on reassoc-to-same-BSS");
+		wpabuf_free(resp);
+		sme_associate(wpa_s, ssid->mode, bss->bssid, WLAN_AUTH_OPEN);
+		return;
+	}
+
+
 	wpa_s->sme.auth_alg = params.auth_alg;
 	if (wpa_drv_authenticate(wpa_s, &params) < 0) {
 		wpa_msg(wpa_s, MSG_INFO, "SME: Authentication request to the "