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author | Matthias Schiffer <mschiffer@universe-factory.net> | 2013-10-28 18:27:10 +0100 |
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committer | Matthias Schiffer <mschiffer@universe-factory.net> | 2013-10-28 18:31:02 +0100 |
commit | fc8c8d82f05911836208cc9169e103d5578ffd70 (patch) | |
tree | 06aad5eebfa87982ae95a76bb5644161fc73c6df /src/methods/common.c | |
parent | 095ca93d81cfae0fcb137919231810577c556404 (diff) | |
download | fastd-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.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/src/methods/common.c b/src/methods/common.c new file mode 100644 index 0000000..7c67253 --- /dev/null +++ b/src/methods/common.c @@ -0,0 +1,90 @@ +/* + 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; + } +} |