From 587fc0ea6961694b5662485a60ba7f586363d440 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Florian=20M=C3=A4rkl?= <info@florianmaerkl.de>
Date: Sun, 25 Nov 2018 16:21:42 +0100
Subject: [PATCH] Nagare receive bang

---
 lib/src/nagare.c   | 78 ++++++++++++++++++++++++++++++++++++++++------
 lib/src/pb_utils.h | 25 +++++++++++++++
 2 files changed, 93 insertions(+), 10 deletions(-)

diff --git a/lib/src/nagare.c b/lib/src/nagare.c
index 159df20..a0b39e2 100644
--- a/lib/src/nagare.c
+++ b/lib/src/nagare.c
@@ -41,6 +41,7 @@
 static void nagare_takion_data(uint8_t *buf, size_t buf_size, void *user);
 static ChiakiErrorCode nagare_send_big(ChiakiNagare *nagare);
 static ChiakiErrorCode nagare_send_disconnect(ChiakiNagare *nagare);
+static void nagare_handle_bang(ChiakiNagare *nagare, tkproto_BangPayload *payload);
 
 CHIAKI_EXPORT ChiakiErrorCode chiaki_nagare_run(ChiakiSession *session)
 {
@@ -120,11 +121,18 @@ error_bang_mirai:
 
 
 
+static void nagare_takion_data_expect_bang(ChiakiNagare *nagare, uint8_t *buf, size_t buf_size);
 
 static void nagare_takion_data(uint8_t *buf, size_t buf_size, void *user)
 {
 	ChiakiNagare *nagare = user;
 
+	if(nagare->bang_mirai.expected)
+	{
+		nagare_takion_data_expect_bang(nagare, buf, buf_size);
+		return;
+	}
+
 	tkproto_TakionMessage msg;
 	memset(&msg, 0, sizeof(msg));
 
@@ -135,18 +143,68 @@ static void nagare_takion_data(uint8_t *buf, size_t buf_size, void *user)
 		CHIAKI_LOGE(nagare->log, "Nagare failed to decode data protobuf\n");
 		return;
 	}
-
-	if(nagare->bang_mirai.expected)
-	{
-		if(msg.type != tkproto_TakionMessage_PayloadType_BANG || !msg.has_bang_payload)
-		{
-			CHIAKI_LOGE(nagare->log, "Nagare expected bang payload but received something else\n");
-			return;
-		}
-		chiaki_mirai_signal(&nagare->bang_mirai, true);
-	}
 }
 
+static void nagare_takion_data_expect_bang(ChiakiNagare *nagare, uint8_t *buf, size_t buf_size)
+{
+	char ecdh_pub_key[128];
+	ChiakiPBDecodeBuf ecdh_pub_key_buf = { sizeof(ecdh_pub_key), 0, ecdh_pub_key };
+	char ecdh_sig[32];
+	ChiakiPBDecodeBuf ecdh_sig_buf = { sizeof(ecdh_sig), 0, ecdh_sig };
+
+	tkproto_TakionMessage msg;
+	memset(&msg, 0, sizeof(msg));
+
+	msg.bang_payload.ecdh_pub_key.arg = &ecdh_pub_key_buf;
+	msg.bang_payload.ecdh_pub_key.funcs.decode = chiaki_pb_decode_buf;
+	msg.bang_payload.ecdh_sig.arg = &ecdh_sig_buf;
+	msg.bang_payload.ecdh_sig.funcs.decode = chiaki_pb_decode_buf;
+
+	pb_istream_t stream = pb_istream_from_buffer(buf, buf_size);
+	bool r = pb_decode(&stream, tkproto_TakionMessage_fields, &msg);
+	if(!r)
+	{
+		CHIAKI_LOGE(nagare->log, "Nagare failed to decode data protobuf\n");
+		return;
+	}
+
+	if(msg.type != tkproto_TakionMessage_PayloadType_BANG || !msg.has_bang_payload)
+	{
+		CHIAKI_LOGE(nagare->log, "Nagare expected bang payload but received something else\n");
+		return;
+	}
+
+	if(!msg.bang_payload.version_accepted)
+	{
+		CHIAKI_LOGE(nagare->log, "Nagare bang remote didn't accept version\n");
+		goto error;
+	}
+
+	if(!msg.bang_payload.encrypted_key_accepted)
+	{
+		CHIAKI_LOGE(nagare->log, "Nagare bang remote didn't accept encrypted key\n");
+		goto error;
+	}
+
+	if(!ecdh_pub_key_buf.size)
+	{
+		CHIAKI_LOGE(nagare->log, "Nagare didn't get remote ECDH pub key from bang\n");
+		goto error;
+	}
+
+	if(!ecdh_sig_buf.size)
+	{
+		CHIAKI_LOGE(nagare->log, "Nagare didn't get remote ECDH sig from bang\n");
+		goto error;
+	}
+
+	CHIAKI_LOGI(nagare->log, "Nagare bang looks good so far\n");
+
+error:
+	chiaki_mirai_signal(&nagare->bang_mirai, true);
+}
+
+
 
 static bool chiaki_pb_encode_zero_encrypted_key(pb_ostream_t *stream, const pb_field_t *field, void *const *arg)
 {
diff --git a/lib/src/pb_utils.h b/lib/src/pb_utils.h
index c2aa4a9..db9bf8c 100644
--- a/lib/src/pb_utils.h
+++ b/lib/src/pb_utils.h
@@ -19,6 +19,7 @@
 #define CHIAKI_PB_UTILS_H
 
 #include <pb_encode.h>
+#include <pb_decode.h>
 
 static bool chiaki_pb_encode_string(pb_ostream_t *stream, const pb_field_t *field, void *const *arg)
 {
@@ -47,4 +48,28 @@ static bool chiaki_pb_encode_buf(pb_ostream_t *stream, const pb_field_t *field,
 }
 
 
+typedef struct chiaki_pb_decode_buf_t
+{
+	size_t max_size;
+	size_t size;
+	uint8_t *buf;
+} ChiakiPBDecodeBuf;
+
+static bool chiaki_pb_decode_buf(pb_istream_t *stream, const pb_field_t *field, void **arg)
+{
+	ChiakiPBDecodeBuf *buf = *arg;
+	if(stream->bytes_left > buf->max_size)
+	{
+		buf->size = 0;
+		return false;
+	}
+
+	buf->size = stream->bytes_left;
+	bool r = pb_read(stream, buf->buf, buf->size);
+	if(!r)
+		buf->size = 0;
+	return r;
+}
+
+
 #endif // CHIAKI_PB_UTILS_H