From 522450b7b1e2bcaae8cb091531611ae6992b7ecc Mon Sep 17 00:00:00 2001
From: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Date: Wed, 19 Jun 2019 15:49:15 +0300
Subject: [PATCH] AP: Determine Short SSID value for the BSS

This can be used in the future to implement support for RNR and scanning
extensions using a shorter field for the SSID.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
---
 hostapd/Android.mk        | 1 +
 hostapd/Makefile          | 1 +
 src/ap/ap_config.h        | 1 +
 src/ap/hostapd.c          | 7 +++++++
 wpa_supplicant/Android.mk | 1 +
 wpa_supplicant/Makefile   | 1 +
 6 files changed, 12 insertions(+)

diff --git a/hostapd/Android.mk b/hostapd/Android.mk
index a87ac8144..82fa3ea73 100644
--- a/hostapd/Android.mk
+++ b/hostapd/Android.mk
@@ -145,6 +145,7 @@ OBJS += src/utils/wpa_debug.c
 OBJS += src/utils/wpabuf.c
 OBJS += src/utils/os_$(CONFIG_OS).c
 OBJS += src/utils/ip_addr.c
+OBJS += src/utils/crc32.c
 
 OBJS += src/common/ieee802_11_common.c
 OBJS += src/common/wpa_common.c
diff --git a/hostapd/Makefile b/hostapd/Makefile
index 955e27856..f1896f2e3 100644
--- a/hostapd/Makefile
+++ b/hostapd/Makefile
@@ -158,6 +158,7 @@ OBJS_c += ../src/utils/wpa_debug.o
 OBJS += ../src/utils/wpabuf.o
 OBJS += ../src/utils/os_$(CONFIG_OS).o
 OBJS += ../src/utils/ip_addr.o
+OBJS += ../src/utils/crc32.o
 
 OBJS += ../src/common/ieee802_11_common.o
 OBJS += ../src/common/wpa_common.o
diff --git a/src/ap/ap_config.h b/src/ap/ap_config.h
index 83b8aee65..7e4b9262c 100644
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -88,6 +88,7 @@ typedef enum hostap_security_policy {
 struct hostapd_ssid {
 	u8 ssid[SSID_MAX_LEN];
 	size_t ssid_len;
+	u32 short_ssid;
 	unsigned int ssid_set:1;
 	unsigned int utf8_ssid:1;
 	unsigned int wpa_passphrase_set:1;
diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index e4950e3ed..516d571ae 100644
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -13,6 +13,7 @@
 
 #include "utils/common.h"
 #include "utils/eloop.h"
+#include "utils/crc32.h"
 #include "common/ieee802_11_defs.h"
 #include "common/wpa_ctrl.h"
 #include "common/hw_features_common.h"
@@ -1190,6 +1191,12 @@ static int hostapd_setup_bss(struct hostapd_data *hapd, int first)
 		os_memcpy(conf->ssid.ssid, ssid, conf->ssid.ssid_len);
 	}
 
+	/*
+	 * Short SSID calculation is identical to FCS and it is defined in
+	 * IEEE P802.11-REVmd/D3.0, 9.4.2.170.3 (Calculating the Short-SSID).
+	 */
+	conf->ssid.short_ssid = crc32(conf->ssid.ssid, conf->ssid.ssid_len);
+
 	if (!hostapd_drv_none(hapd)) {
 		wpa_printf(MSG_ERROR, "Using interface %s with hwaddr " MACSTR
 			   " and ssid \"%s\"",
diff --git a/wpa_supplicant/Android.mk b/wpa_supplicant/Android.mk
index cd93d48b9..98f3b52a2 100644
--- a/wpa_supplicant/Android.mk
+++ b/wpa_supplicant/Android.mk
@@ -94,6 +94,7 @@ OBJS += src/utils/wpa_debug.c
 OBJS += src/utils/wpabuf.c
 OBJS += src/utils/bitfield.c
 OBJS += src/utils/ip_addr.c
+OBJS += src/utils/crc32.c
 OBJS += wmm_ac.c
 OBJS += op_classes.c
 OBJS += rrm.c
diff --git a/wpa_supplicant/Makefile b/wpa_supplicant/Makefile
index 94f9165bb..96dc5bd0f 100644
--- a/wpa_supplicant/Makefile
+++ b/wpa_supplicant/Makefile
@@ -104,6 +104,7 @@ OBJS += ../src/utils/wpa_debug.o
 OBJS += ../src/utils/wpabuf.o
 OBJS += ../src/utils/bitfield.o
 OBJS += ../src/utils/ip_addr.o
+OBJS += ../src/utils/crc32.o
 OBJS += op_classes.o
 OBJS += rrm.o
 OBJS_p = wpa_passphrase.o