From 1c7f652f9e702fff3165f7909305c601c224a961 Mon Sep 17 00:00:00 2001
From: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Date: Wed, 19 Jun 2019 15:49:16 +0300
Subject: [PATCH] AP: Support Short SSID List element in Probe Request frames

According to IEEE P802.11ax/D6.0, 11.1.4.3.4 (Criteria for sending a
response), AP should answer Probe Request frames if either SSID or Short
SSID matches. Implement this part of the Short SSID use for the BSS (the
collocated 6 GHz BSS case is not covered in this commit).

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
---
 src/ap/beacon.c                | 45 ++++++++++++++++++++++------------
 src/common/ieee802_11_common.c |  4 +++
 src/common/ieee802_11_common.h |  2 ++
 src/common/ieee802_11_defs.h   |  1 +
 4 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/src/ap/beacon.c b/src/ap/beacon.c
index 331c09bc2..793c10a4d 100644
--- a/src/ap/beacon.c
+++ b/src/ap/beacon.c
@@ -581,7 +581,9 @@ enum ssid_match_result {
 static enum ssid_match_result ssid_match(struct hostapd_data *hapd,
 					 const u8 *ssid, size_t ssid_len,
 					 const u8 *ssid_list,
-					 size_t ssid_list_len)
+					 size_t ssid_list_len,
+					 const u8 *short_ssid_list,
+					 size_t short_ssid_list_len)
 {
 	const u8 *pos, *end;
 	int wildcard = 0;
@@ -592,20 +594,30 @@ static enum ssid_match_result ssid_match(struct hostapd_data *hapd,
 	    os_memcmp(ssid, hapd->conf->ssid.ssid, ssid_len) == 0)
 		return EXACT_SSID_MATCH;
 
-	if (ssid_list == NULL)
-		return wildcard ? WILDCARD_SSID_MATCH : NO_SSID_MATCH;
+	if (ssid_list) {
+		pos = ssid_list;
+		end = ssid_list + ssid_list_len;
+		while (end - pos >= 2) {
+			if (2 + pos[1] > end - pos)
+				break;
+			if (pos[1] == 0)
+				wildcard = 1;
+			if (pos[1] == hapd->conf->ssid.ssid_len &&
+			    os_memcmp(pos + 2, hapd->conf->ssid.ssid,
+				      pos[1]) == 0)
+				return EXACT_SSID_MATCH;
+			pos += 2 + pos[1];
+		}
+	}
 
-	pos = ssid_list;
-	end = ssid_list + ssid_list_len;
-	while (end - pos >= 2) {
-		if (2 + pos[1] > end - pos)
-			break;
-		if (pos[1] == 0)
-			wildcard = 1;
-		if (pos[1] == hapd->conf->ssid.ssid_len &&
-		    os_memcmp(pos + 2, hapd->conf->ssid.ssid, pos[1]) == 0)
-			return EXACT_SSID_MATCH;
-		pos += 2 + pos[1];
+	if (short_ssid_list) {
+		pos = short_ssid_list;
+		end = short_ssid_list + short_ssid_list_len;
+		while (end - pos >= 4) {
+			if (hapd->conf->ssid.short_ssid == WPA_GET_LE32(pos))
+				return EXACT_SSID_MATCH;
+			pos += 4;
+		}
 	}
 
 	return wildcard ? WILDCARD_SSID_MATCH : NO_SSID_MATCH;
@@ -838,7 +850,7 @@ void handle_probe_req(struct hostapd_data *hapd,
 #endif /* CONFIG_P2P */
 
 	if (hapd->conf->ignore_broadcast_ssid && elems.ssid_len == 0 &&
-	    elems.ssid_list_len == 0) {
+	    elems.ssid_list_len == 0 && elems.short_ssid_list_len == 0) {
 		wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR " for "
 			   "broadcast SSID ignored", MAC2STR(mgmt->sa));
 		return;
@@ -870,7 +882,8 @@ void handle_probe_req(struct hostapd_data *hapd,
 #endif /* CONFIG_TAXONOMY */
 
 	res = ssid_match(hapd, elems.ssid, elems.ssid_len,
-			 elems.ssid_list, elems.ssid_list_len);
+			 elems.ssid_list, elems.ssid_list_len,
+			 elems.short_ssid_list, elems.short_ssid_list_len);
 	if (res == NO_SSID_MATCH) {
 		if (!(mgmt->da[0] & 0x01)) {
 			wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR
diff --git a/src/common/ieee802_11_common.c b/src/common/ieee802_11_common.c
index 046a25d6c..36005d75f 100644
--- a/src/common/ieee802_11_common.c
+++ b/src/common/ieee802_11_common.c
@@ -282,6 +282,10 @@ static int ieee802_11_parse_extension(const u8 *pos, size_t elen,
 		elems->oci = pos;
 		elems->oci_len = elen;
 		break;
+	case WLAN_EID_EXT_SHORT_SSID_LIST:
+		elems->short_ssid_list = pos;
+		elems->short_ssid_list_len = elen;
+		break;
 	default:
 		if (show_errors) {
 			wpa_printf(MSG_MSGDUMP,
diff --git a/src/common/ieee802_11_common.h b/src/common/ieee802_11_common.h
index fbda10c7a..d13316969 100644
--- a/src/common/ieee802_11_common.h
+++ b/src/common/ieee802_11_common.h
@@ -96,6 +96,7 @@ struct ieee802_11_elems {
 	const u8 *multi_ap;
 	const u8 *he_capabilities;
 	const u8 *he_operation;
+	const u8 *short_ssid_list;
 
 	u8 ssid_len;
 	u8 supp_rates_len;
@@ -147,6 +148,7 @@ struct ieee802_11_elems {
 	u8 multi_ap_len;
 	u8 he_capabilities_len;
 	u8 he_operation_len;
+	u8 short_ssid_list_len;
 
 	struct mb_ies_info mb_ies;
 };
diff --git a/src/common/ieee802_11_defs.h b/src/common/ieee802_11_defs.h
index e3c2ed310..d999a3665 100644
--- a/src/common/ieee802_11_defs.h
+++ b/src/common/ieee802_11_defs.h
@@ -472,6 +472,7 @@
 #define WLAN_EID_EXT_HE_MU_EDCA_PARAMS 38
 #define WLAN_EID_EXT_SPATIAL_REUSE 39
 #define WLAN_EID_EXT_OCV_OCI 54
+#define WLAN_EID_EXT_SHORT_SSID_LIST 58
 #define WLAN_EID_EXT_EDMG_CAPABILITIES 61
 #define WLAN_EID_EXT_EDMG_OPERATION 62
 #define WLAN_EID_EXT_REJECTED_GROUPS 92