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authorMatthias Schiffer <mschiffer@universe-factory.net>2013-10-28 18:27:10 +0100
committerMatthias Schiffer <mschiffer@universe-factory.net>2013-10-28 18:31:02 +0100
commitfc8c8d82f05911836208cc9169e103d5578ffd70 (patch)
tree06aad5eebfa87982ae95a76bb5644161fc73c6df /src/methods/common.c
parent095ca93d81cfae0fcb137919231810577c556404 (diff)
downloadfastd-fc8c8d82f05911836208cc9169e103d5578ffd70.tar
fastd-fc8c8d82f05911836208cc9169e103d5578ffd70.zip
Unify duplicate code in xsalsa20-poly1305 and aes128-gcm methods
Diffstat (limited to 'src/methods/common.c')
-rw-r--r--src/methods/common.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/src/methods/common.c b/src/methods/common.c
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+/*
+ 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.
+*/
+
+
+#include "common.h"
+
+
+void fastd_method_common_init(fastd_context_t *ctx, fastd_method_common_t *session, bool initiator) {
+ memset(session, 0, sizeof(*session));
+
+ session->valid_till = ctx->now;
+ session->valid_till.tv_sec += ctx->conf->key_valid;
+
+ session->refresh_after = ctx->now;
+ 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;
+ }
+ else {
+ session->send_nonce[0] = 2;
+ session->receive_nonce[0] = 1;
+ }
+}
+
+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) {
+ if ((nonce[0] & 1) != (session->receive_nonce[0] & 1))
+ return false;
+
+ int i;
+ *age = 0;
+
+ for (i = COMMON_NONCEBYTES-1; i >= 0; i--) {
+ *age *= 256;
+ *age += session->receive_nonce[i]-nonce[i];
+ }
+
+ *age /= 2;
+
+ if (*age >= 0) {
+ if (timespec_diff(&ctx->now, &session->receive_last) > (int)ctx->conf->reorder_time*1000)
+ return false;
+
+ if (*age > ctx->conf->reorder_count)
+ return false;
+ }
+
+ return true;
+}
+
+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) {
+ if (age < 0) {
+ session->receive_reorder_seen >>= age;
+ session->receive_reorder_seen |= (1 >> (age+1));
+ memcpy(session->receive_nonce, nonce, COMMON_NONCEBYTES);
+ session->receive_last = ctx->now;
+ return true;
+ }
+ else if (age == 0 || session->receive_reorder_seen & (1 << (age-1))) {
+ pr_debug(ctx, "dropping duplicate packet from %P (age %u)", peer, (unsigned)age);
+ return false;
+ }
+ else {
+ pr_debug2(ctx, "accepting reordered packet from %P (age %u)", peer, (unsigned)age);
+ session->receive_reorder_seen |= (1 << (age-1));
+ return true;
+ }
+}