Use 2 bytes to encode handshake field types and lengths; breaks compatiblity with v0.1-rc2 and earlier

3 files changed, 25 insertions, 21 deletions

diff --git a/src/handshake.c b/src/handshake.c
index 839951b..a17fd2b 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -58,8 +58,8 @@ static const char const *REPLY_TYPES[REPLY_MAX] = {
 fastd_buffer fastd_handshake_new_init(fastd_context *ctx, fastd_peer *peer, size_t tail_space) {
 	size_t protocol_len = strlen(ctx->conf->protocol->name);
 	fastd_buffer buffer = fastd_buffer_alloc(sizeof(fastd_packet), 0,
-						 2*3 +           /* handshake type, mode */
-						 2+protocol_len+ /* protocol name */
+						 2*5 +           /* handshake type, mode */
+						 4+protocol_len+ /* protocol name */
 						 tail_space
 						 );
 	fastd_packet *request = buffer.data;
@@ -77,7 +77,7 @@ fastd_buffer fastd_handshake_new_init(fastd_context *ctx, fastd_peer *peer, size
 
 fastd_buffer fastd_handshake_new_reply(fastd_context *ctx, fastd_peer *peer, const fastd_handshake *handshake, size_t tail_space) {
 	fastd_buffer buffer = fastd_buffer_alloc(sizeof(fastd_packet), 0,
-						 2*3 +           /* handshake type, reply code */
+						 2*5 +           /* handshake type, reply code */
 						 tail_space
 						 );
 	fastd_packet *request = buffer.data;
@@ -105,19 +105,19 @@ void fastd_handshake_handle(fastd_context *ctx, fastd_peer *peer, fastd_buffer b
 
 	uint8_t *ptr = packet->tlv_data;
 	while (true) {
-		if (ptr+2 > (uint8_t*)buffer.data + buffer.len)
+		if (ptr+4 > (uint8_t*)buffer.data + buffer.len)
 			break;
 
-		uint8_t type = ptr[0];
-		uint8_t len = ptr[1];
+		uint16_t type = ptr[0] + (ptr[1] << 8);
+		uint16_t len = ptr[2] + (ptr[3] << 8);
 
-		if (ptr+2+len > (uint8_t*)buffer.data + buffer.len)
+		if (ptr+4+len > (uint8_t*)buffer.data + buffer.len)
 			break;
 
 		handshake.records[type].length = len;
-		handshake.records[type].data = ptr+2;
+		handshake.records[type].data = ptr+4;
 
-		ptr += 2+len;
+		ptr += 4+len;
 	}
 
 	handshake.req_id = packet->req_id;
@@ -160,7 +160,7 @@ void fastd_handshake_handle(fastd_context *ctx, fastd_peer *peer, fastd_buffer b
 
 	send_reply:
 		if (reply_code) {
-			fastd_buffer reply_buffer = fastd_buffer_alloc(sizeof(fastd_packet), 0, 3*3 /* enough space for handshake type, reply code and error detail */);
+			fastd_buffer reply_buffer = fastd_buffer_alloc(sizeof(fastd_packet), 0, 3*5 /* enough space for handshake type, reply code and error detail */);
 			fastd_packet *reply = reply_buffer.data;
 
 			reply->req_id = packet->req_id;
diff --git a/src/handshake.h b/src/handshake.h
index c59d141..d540de0 100644
--- a/src/handshake.h
+++ b/src/handshake.h
@@ -72,29 +72,33 @@ void fastd_handshake_handle(fastd_context *ctx, fastd_peer *peer, fastd_buffer b
 
 
 static inline void fastd_handshake_add(fastd_context *ctx, fastd_buffer *buffer, fastd_handshake_record_type type, size_t len, const void *data) {
-	if ((uint8_t*)buffer->data + buffer->len + 2 + len > (uint8_t*)buffer->base + buffer->base_len)
+	if ((uint8_t*)buffer->data + buffer->len + 4 + len > (uint8_t*)buffer->base + buffer->base_len)
 		exit_bug(ctx, "not enough buffer allocated for handshake");
 
 	uint8_t *dst = (uint8_t*)buffer->data + buffer->len;
 
 	dst[0] = type;
-	dst[1] = len;
-	memcpy(dst+2, data, len);
+	dst[1] = type >> 8;
+	dst[2] = len;
+	dst[3] = len >> 8;
+	memcpy(dst+4, data, len);
 
-	buffer->len += 2 + len;
+	buffer->len += 4 + len;
 }
 
 static inline void fastd_handshake_add_uint8(fastd_context *ctx, fastd_buffer *buffer, fastd_handshake_record_type type, uint8_t value) {
-	if ((uint8_t*)buffer->data + buffer->len + 3 > (uint8_t*)buffer->base + buffer->base_len)
+	if ((uint8_t*)buffer->data + buffer->len + 5 > (uint8_t*)buffer->base + buffer->base_len)
 		exit_bug(ctx, "not enough buffer allocated for handshake");
 
 	uint8_t *dst = (uint8_t*)buffer->data + buffer->len;
 
 	dst[0] = type;
-	dst[1] = 1;
-	dst[2] = value;
+	dst[1] = type >> 8;
+	dst[2] = 1;
+	dst[3] = 0;
+	dst[4] = value;
 
-	buffer->len += 3;
+	buffer->len += 5;
 }
 
 
diff --git a/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c b/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c
index 326d1b5..29c02fa 100644
--- a/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c
+++ b/src/protocol_ec25519_fhmqvc_xsalsa20_poly1305.c
@@ -277,7 +277,7 @@ static protocol_handshake* new_handshake(fastd_context *ctx, fastd_peer *peer, c
 static void protocol_handshake_init(fastd_context *ctx, fastd_peer *peer) {
 	init_peer_state(ctx, peer);
 
-	fastd_buffer buffer = fastd_handshake_new_init(ctx, peer, 3*(2+PUBLICKEYBYTES) /* sender key, receipient key, handshake key */);
+	fastd_buffer buffer = fastd_handshake_new_init(ctx, peer, 3*(4+PUBLICKEYBYTES) /* sender key, receipient key, handshake key */);
 
 	protocol_handshake *handshake = new_handshake(ctx, peer, peer->config, true);
 
@@ -343,7 +343,7 @@ static void respond_handshake(fastd_context *ctx, fastd_peer *peer, const fastd_
 
 	crypto_auth_hmacsha256(hmacbuf, hashinput, 2*PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->shared_handshake_key);
 
-	fastd_buffer buffer = fastd_handshake_new_reply(ctx, peer, handshake, 4*(2+PUBLICKEYBYTES) + 2+HMACBYTES);
+	fastd_buffer buffer = fastd_handshake_new_reply(ctx, peer, handshake, 4*(4+PUBLICKEYBYTES) + 4+HMACBYTES);
 
 	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p);
 	fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, peer->protocol_state->accepting_handshake->peer_config->protocol_config->public_key.p);
@@ -475,7 +475,7 @@ static void finish_handshake(fastd_context *ctx, fastd_peer *peer, const fastd_h
 	memcpy(hashinput+PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->public_key.p, PUBLICKEYBYTES);
 	crypto_auth_hmacsha256(hmacbuf, hashinput, 2*PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->shared_handshake_key);
 
-	fastd_buffer buffer = fastd_handshake_new_reply(ctx, peer, handshake, 4*(2+PUBLICKEYBYTES) + 2+HMACBYTES);
+	fastd_buffer buffer = fastd_handshake_new_reply(ctx, peer, handshake, 4*(4+PUBLICKEYBYTES) + 4+HMACBYTES);
 
 	fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->public_key.p);
 	fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, peer->protocol_state->initiating_handshake->peer_config->protocol_config->public_key.p);