Unify duplicate code in xsalsa20-poly1305 and aes128-gcm methods

1 files changed, 86 insertions, 0 deletions

diff --git a/src/methods/common.h b/src/methods/common.h
new file mode 100644
index 0000000..0337265
--- /dev/null
+++ b/src/methods/common.h
@@ -0,0 +1,86 @@
+/*
+  Copyright (c) 2012-2013, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#ifndef _FASTD_METHODS_COMMON_H_
+#define _FASTD_METHODS_COMMON_H_
+
+#include <fastd.h>
+
+
+#define COMMON_NONCEBYTES 7
+
+
+typedef struct fastd_method_common {
+	struct timespec valid_till;
+	struct timespec refresh_after;
+
+	uint8_t send_nonce[COMMON_NONCEBYTES];
+	uint8_t receive_nonce[COMMON_NONCEBYTES];
+
+	struct timespec receive_last;
+	uint64_t receive_reorder_seen;
+} fastd_method_common_t;
+
+
+void fastd_method_common_init(fastd_context_t *ctx, fastd_method_common_t *session, bool initiator);
+bool fastd_method_is_nonce_valid(fastd_context_t *ctx, const fastd_method_common_t *session, const uint8_t nonce[COMMON_NONCEBYTES], int64_t *age);
+bool fastd_method_reorder_check(fastd_context_t *ctx, fastd_peer_t *peer, fastd_method_common_t *session, const uint8_t nonce[COMMON_NONCEBYTES], int64_t age);
+
+
+static inline bool fastd_method_session_common_is_valid(fastd_context_t *ctx, const fastd_method_common_t *session) {
+	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);
+}
+
+static inline bool fastd_method_session_common_want_refresh(fastd_context_t *ctx, const fastd_method_common_t *session) {
+	return timespec_after(&ctx->now, &session->refresh_after);
+}
+
+static inline void fastd_method_session_common_superseded(fastd_context_t *ctx, fastd_method_common_t *session) {
+	struct timespec valid_max = ctx->now;
+	valid_max.tv_sec += ctx->conf->key_valid_old;
+
+	if (timespec_after(&session->valid_till, &valid_max))
+		session->valid_till = valid_max;
+}
+
+static inline void fastd_method_increment_nonce(fastd_method_common_t *session) {
+	session->send_nonce[0] += 2;
+
+	if (session->send_nonce[0] == 0 || session->send_nonce[0] == 1) {
+		int i;
+		for (i = 1; i < COMMON_NONCEBYTES; i++) {
+			session->send_nonce[i]++;
+			if (session->send_nonce[i] != 0)
+				break;
+		}
+	}
+}
+
+#endif /* _FASTD_METHODS_COMMON_H_ */