From d59086c7911983db0f015699305cb111cf1af7a6 Mon Sep 17 00:00:00 2001
From: Denis Kenzior <denkenz@gmail.com>
Date: Tue, 30 Aug 2016 13:57:28 -0500
Subject: [PATCH] wscutil: Add wsc_build_m4_encrypted_settings

---
 src/wscutil.c | 27 +++++++++++++++++++++++++++
 src/wscutil.h |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/src/wscutil.c b/src/wscutil.c
index 49c27acc..fc34478f 100644
--- a/src/wscutil.c
+++ b/src/wscutil.c
@@ -1463,6 +1463,13 @@ static void build_enrollee_nonce(struct wsc_attr_builder *builder,
 	wsc_attr_builder_put_bytes(builder, nonce, 16);
 }
 
+static void build_key_wrap_authenticator(struct wsc_attr_builder *builder,
+						const uint8_t *authenticator)
+{
+	wsc_attr_builder_start_attr(builder, WSC_ATTR_KEY_WRAP_AUTHENTICATOR);
+	wsc_attr_builder_put_bytes(builder, authenticator, 8);
+}
+
 static void build_mac_address(struct wsc_attr_builder *builder,
 							const uint8_t *addr)
 {
@@ -1556,6 +1563,13 @@ static void build_r_hash2(struct wsc_attr_builder *builder,
 	wsc_attr_builder_put_bytes(builder, r_hash2, 32);
 }
 
+static void build_r_snonce1(struct wsc_attr_builder *builder,
+							const uint8_t *nonce)
+{
+	wsc_attr_builder_start_attr(builder, WSC_ATTR_R_SNONCE1);
+	wsc_attr_builder_put_bytes(builder, nonce, 16);
+}
+
 static void build_serial_number(struct wsc_attr_builder *builder,
 						const char *serial_number)
 {
@@ -1772,6 +1786,19 @@ done:
 	return ret;
 }
 
+uint8_t *wsc_build_m4_encrypted_settings(
+				const struct wsc_m4_encrypted_settings *in,
+				size_t *out_len)
+{
+	struct wsc_attr_builder *builder;
+
+	builder = wsc_attr_builder_new(256);
+	build_r_snonce1(builder, in->r_snonce1);
+	build_key_wrap_authenticator(builder, in->authenticator);
+
+	return wsc_attr_builder_free(builder, false, out_len);
+}
+
 uint8_t *wsc_build_m5(const struct wsc_m5 *m5, const uint8_t *encrypted,
 			size_t encrypted_len, size_t *out_len)
 {
diff --git a/src/wscutil.h b/src/wscutil.h
index 632cba13..f853d2e0 100644
--- a/src/wscutil.h
+++ b/src/wscutil.h
@@ -498,6 +498,9 @@ uint8_t *wsc_build_m2(const struct wsc_m2 *m2, size_t *out_len);
 uint8_t *wsc_build_m3(const struct wsc_m3 *m3, size_t *out_len);
 uint8_t *wsc_build_m4(const struct wsc_m4 *m4, const uint8_t *encrypted,
 			size_t encrypted_len, size_t *out_len);
+uint8_t *wsc_build_m4_encrypted_settings(
+				const struct wsc_m4_encrypted_settings *in,
+				size_t *out_len);
 uint8_t *wsc_build_m5(const struct wsc_m5 *m5, const uint8_t *encrypted,
 			size_t encrypted_len, size_t *out_len);