Change common packet header: flags comes first, nonce is big endian

2 files changed, 17 insertions, 18 deletions

diff --git a/src/methods/common.c b/src/methods/common.c
index 9308332..7118ef4 100644
--- a/src/methods/common.c
+++ b/src/methods/common.c
@@ -37,11 +37,11 @@ void fastd_method_common_init(fastd_context_t *ctx, fastd_method_common_t *sessi
 	session->refresh_after.tv_sec += ctx->conf->key_refresh - fastd_rand(ctx, 0, ctx->conf->key_refresh_splay);
 
 	if (initiator) {
-		session->send_nonce[0] = 3;
+		session->send_nonce[COMMON_NONCEBYTES-1] = 3;
 	}
 	else {
-		session->send_nonce[0] = 2;
-		session->receive_nonce[0] = 1;
+		session->send_nonce[COMMON_NONCEBYTES-1] = 2;
+		session->receive_nonce[COMMON_NONCEBYTES-1] = 1;
 	}
 }
 
@@ -49,15 +49,15 @@ bool fastd_method_is_nonce_valid(fastd_context_t *ctx, const fastd_method_common
 	if ((nonce[0] & 1) != (session->receive_nonce[0] & 1))
 		return false;
 
-	int i;
+	size_t i;
 	*age = 0;
 
-	for (i = COMMON_NONCEBYTES-1; i >= 0; i--) {
-		*age *= 256;
-		*age += session->receive_nonce[i]-nonce[i];
+	for (i = 0; i < COMMON_NONCEBYTES; i++) {
+		*age <<= 8;
+		*age += session->receive_nonce[i] - nonce[i];
 	}
 
-	*age /= 2;
+	*age >>= 1;
 
 	if (*age >= 0) {
 		if (timespec_diff(&ctx->now, &session->receive_last) > (int)ctx->conf->reorder_time*1000)
diff --git a/src/methods/common.h b/src/methods/common.h
index b5f7272..0bd7aae 100644
--- a/src/methods/common.h
+++ b/src/methods/common.h
@@ -53,18 +53,18 @@ bool fastd_method_reorder_check(fastd_context_t *ctx, fastd_peer_t *peer, fastd_
 
 
 static inline bool fastd_method_session_common_is_valid(fastd_context_t *ctx, const fastd_method_common_t *session) {
-	if (session->send_nonce[COMMON_NONCEBYTES-1] == 0xff && session->send_nonce[COMMON_NONCEBYTES-2] == 0xff)
+	if (session->send_nonce[0] == 0xff && session->send_nonce[1] == 0xff)
 		return false;
 
 	return (timespec_after(&session->valid_till, &ctx->now));
 }
 
 static inline bool fastd_method_session_common_is_initiator(const fastd_method_common_t *session) {
-	return (session->send_nonce[0] & 1);
+	return (session->send_nonce[COMMON_NONCEBYTES-1] & 1);
 }
 
 static inline bool fastd_method_session_common_want_refresh(fastd_context_t *ctx, const fastd_method_common_t *session) {
-	if (session->send_nonce[COMMON_NONCEBYTES-1] == 0xff)
+	if (session->send_nonce[0] == 0xff)
 		return true;
 
 	if (fastd_method_session_common_is_initiator(session) && timespec_after(&ctx->now, &session->refresh_after))
@@ -82,26 +82,25 @@ static inline void fastd_method_session_common_superseded(fastd_context_t *ctx,
 }
 
 static inline void fastd_method_increment_nonce(fastd_method_common_t *session) {
-	session->send_nonce[0] += 2;
+	session->send_nonce[COMMON_NONCEBYTES-1] += 2;
 
-	if (session->send_nonce[0] == 0 || session->send_nonce[0] == 1) {
+	if (!(session->send_nonce[COMMON_NONCEBYTES-1] & (~1))) {
 		int i;
-		for (i = 1; i < COMMON_NONCEBYTES; i++) {
-			session->send_nonce[i]++;
-			if (session->send_nonce[i] != 0)
+		for (i = COMMON_NONCEBYTES-2; i >= 0; i--) {
+			if (++session->send_nonce[i])
 				break;
 		}
 	}
 }
 
 static inline void fastd_method_put_common_header(fastd_context_t *ctx, fastd_buffer_t *buffer, const uint8_t nonce[COMMON_NONCEBYTES], uint8_t flags) {
-	fastd_buffer_pull_head_from(ctx, buffer, &flags, 1);
 	fastd_buffer_pull_head_from(ctx, buffer, nonce, COMMON_NONCEBYTES);
+	fastd_buffer_pull_head_from(ctx, buffer, &flags, 1);
 }
 
 static inline void fastd_method_take_common_header(fastd_context_t *ctx, fastd_buffer_t *buffer, uint8_t nonce[COMMON_NONCEBYTES], uint8_t *flags) {
-	fastd_buffer_push_head_to(ctx, buffer, nonce, COMMON_NONCEBYTES);
 	fastd_buffer_push_head_to(ctx, buffer, flags, 1);
+	fastd_buffer_push_head_to(ctx, buffer, nonce, COMMON_NONCEBYTES);
 }
 
 static inline bool fastd_method_handle_common_header(fastd_context_t *ctx, const fastd_method_common_t *session, fastd_buffer_t *buffer, uint8_t nonce[COMMON_NONCEBYTES], uint8_t *flags, int64_t *age) {