Initial commit

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 88 insertions, 0 deletions

diff --git a/src/messages.h b/src/messages.h
new file mode 100644
index 0000000..38bead5
--- /dev/null
+++ b/src/messages.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2015-2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * See doc/protocol.md for more info
+ */
+
+#ifndef MESSAGES_H
+#define MESSAGES_H
+
+#include "noise.h"
+#include "cookie.h"
+
+enum message_type {
+	MESSAGE_INVALID = 0,
+	MESSAGE_HANDSHAKE_INITIATION = 1,
+	MESSAGE_HANDSHAKE_RESPONSE = 2,
+	MESSAGE_HANDSHAKE_COOKIE = 3,
+	MESSAGE_DATA = 4,
+	MESSAGE_TOTAL = 5
+};
+
+struct message_header {
+	u8 type;
+} __packed;
+
+struct message_macs {
+	u8 mac1[COOKIE_LEN];
+	u8 mac2[COOKIE_LEN];
+} __packed;
+
+struct message_handshake_initiation {
+	struct message_header header;
+	__le32 sender_index;
+	u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN];
+	u8 encrypted_static[noise_encrypted_len(NOISE_PUBLIC_KEY_LEN)];
+	u8 encrypted_timestamp[noise_encrypted_len(NOISE_TIMESTAMP_LEN)];
+	struct message_macs macs;
+} __packed;
+
+struct message_handshake_response {
+	struct message_header header;
+	__le32 sender_index;
+	__le32 receiver_index;
+	u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN];
+	u8 encrypted_nothing[noise_encrypted_len(0)];
+	struct message_macs macs;
+} __packed;
+
+struct message_handshake_cookie {
+	struct message_header header;
+	__le32 receiver_index;
+	u8 salt[COOKIE_SALT_LEN];
+	u8 encrypted_cookie[noise_encrypted_len(COOKIE_LEN)];
+} __packed;
+
+struct message_data {
+	struct message_header header;
+	__le32 key_idx;
+	__le64 counter;
+	u8 encrypted_data[];
+} __packed;
+
+#define message_data_len(plain_len) (noise_encrypted_len(plain_len) + sizeof(struct message_data))
+
+enum message_alignments {
+	MESSAGE_DATA_TARGET_OFFSET = sizeof(struct message_data),
+	MESSAGE_DATA_TARGET_OPTIMAL_ALIGNMENT = 32, /* Per intel AVX recommendations */
+	MESSAGE_PADDING_MULTIPLE = 16,
+	MESSAGE_MINIMUM_LENGTH = message_data_len(0)
+};
+
+static inline enum message_type message_determine_type(void *src, size_t src_len)
+{
+	struct message_header *header = src;
+	if (unlikely(src_len < sizeof(struct message_header)))
+		return MESSAGE_INVALID;
+	if (header->type == MESSAGE_DATA && src_len >= MESSAGE_MINIMUM_LENGTH)
+		return MESSAGE_DATA;
+	if (header->type == MESSAGE_HANDSHAKE_INITIATION && src_len == sizeof(struct message_handshake_initiation))
+		return MESSAGE_HANDSHAKE_INITIATION;
+	if (header->type == MESSAGE_HANDSHAKE_RESPONSE && src_len == sizeof(struct message_handshake_response))
+		return MESSAGE_HANDSHAKE_RESPONSE;
+	if (header->type == MESSAGE_HANDSHAKE_COOKIE && src_len == sizeof(struct message_handshake_cookie))
+		return MESSAGE_HANDSHAKE_COOKIE;
+	return MESSAGE_INVALID;
+}
+
+#endif