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// Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <openssl/ssl.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include <openssl/nid.h>
#include "../crypto/internal.h"
#include "internal.h"
BSSL_NAMESPACE_BEGIN
DTLS1_STATE::DTLS1_STATE()
: has_change_cipher_spec(false),
outgoing_messages_complete(false),
flight_has_reply(false),
handshake_write_overflow(false),
handshake_read_overflow(false),
sending_flight(false),
sending_ack(false),
queued_key_update(QueuedKeyUpdate::kNone) {}
DTLS1_STATE::~DTLS1_STATE() {}
bool DTLS1_STATE::Init() {
// Set up the initial epochs.
read_epoch.aead = SSLAEADContext::CreateNullCipher();
write_epoch.aead = SSLAEADContext::CreateNullCipher();
if (read_epoch.aead == nullptr || write_epoch.aead == nullptr) {
return false;
}
return true;
}
bool dtls1_new(SSL *ssl) {
if (!tls_new(ssl)) {
return false;
}
UniquePtr<DTLS1_STATE> d1 = MakeUnique<DTLS1_STATE>();
if (!d1 || !d1->Init()) {
tls_free(ssl);
return false;
}
ssl->d1 = d1.release();
return true;
}
void dtls1_free(SSL *ssl) {
tls_free(ssl);
if (ssl == NULL) {
return;
}
Delete(ssl->d1);
ssl->d1 = NULL;
}
void DTLSTimer::StartMicroseconds(OPENSSL_timeval now, uint64_t microseconds) {
uint64_t seconds = microseconds / 1000000;
microseconds %= 1000000;
now.tv_usec += microseconds;
if (now.tv_usec >= 1000000) {
now.tv_usec -= 1000000;
seconds++;
}
if (now.tv_sec > UINT64_MAX - seconds) {
Stop();
return;
}
now.tv_sec += seconds;
expire_time_ = now;
}
void DTLSTimer::Stop() { expire_time_ = {0, 0}; }
bool DTLSTimer::IsExpired(OPENSSL_timeval now) const {
return MicrosecondsRemaining(now) == 0;
}
bool DTLSTimer::IsSet() const {
return expire_time_.tv_sec != 0 || expire_time_.tv_usec != 0;
}
uint64_t DTLSTimer::MicrosecondsRemaining(OPENSSL_timeval now) const {
if (!IsSet()) {
return kNever;
}
if (now.tv_sec > expire_time_.tv_sec ||
(now.tv_sec == expire_time_.tv_sec &&
now.tv_usec >= expire_time_.tv_usec)) {
return 0;
}
uint64_t sec = expire_time_.tv_sec - now.tv_sec;
uint32_t usec;
if (expire_time_.tv_usec >= now.tv_usec) {
usec = expire_time_.tv_usec - now.tv_usec;
} else {
sec--;
usec = expire_time_.tv_usec + 1000000 - now.tv_usec;
}
// If remaining time is less than 15 ms, return 0 to prevent issues because of
// small divergences with socket timeouts.
if (sec == 0 && usec < 15000) {
return 0;
}
if (sec > UINT64_MAX / 1000000) {
return kNever;
}
sec *= 1000000;
if (sec > UINT64_MAX - usec) {
return kNever;
}
return sec + usec;
}
void dtls1_stop_timer(SSL *ssl) {
ssl->d1->num_timeouts = 0;
ssl->d1->retransmit_timer.Stop();
ssl->d1->timeout_duration_ms = ssl->initial_timeout_duration_ms;
}
BSSL_NAMESPACE_END
using namespace bssl;
void DTLSv1_set_initial_timeout_duration(SSL *ssl, uint32_t duration_ms) {
ssl->initial_timeout_duration_ms = duration_ms;
}
int DTLSv1_get_timeout(const SSL *ssl, struct timeval *out) {
if (!SSL_is_dtls(ssl)) {
return 0;
}
OPENSSL_timeval now = ssl_ctx_get_current_time(ssl->ctx.get());
uint64_t remaining_usec =
ssl->d1->retransmit_timer.MicrosecondsRemaining(now);
remaining_usec =
std::min(remaining_usec, ssl->d1->ack_timer.MicrosecondsRemaining(now));
if (remaining_usec == DTLSTimer::kNever) {
return 0; // No timeout is set.
}
uint64_t remaining_sec = remaining_usec / 1000000;
remaining_usec %= 1000000;
// |timeval| uses |time_t|, which may be 32-bit.
const auto kTvSecMax = std::numeric_limits<decltype(out->tv_sec)>::max();
if (remaining_sec > static_cast<uint64_t>(kTvSecMax)) {
out->tv_sec = kTvSecMax; // Saturate the output.
out->tv_usec = 999999;
} else {
out->tv_sec = static_cast<decltype(out->tv_sec)>(remaining_sec);
}
out->tv_usec = remaining_usec;
return 1;
}
int DTLSv1_handle_timeout(SSL *ssl) {
ssl_reset_error_state(ssl);
if (!SSL_is_dtls(ssl)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return -1;
}
if (!ssl->d1->ack_timer.IsSet() && !ssl->d1->retransmit_timer.IsSet()) {
// No timers are running. Don't bother querying the clock.
return 0;
}
OPENSSL_timeval now = ssl_ctx_get_current_time(ssl->ctx.get());
bool any_timer_expired = false;
if (ssl->d1->ack_timer.IsExpired(now)) {
any_timer_expired = true;
ssl->d1->sending_ack = true;
ssl->d1->ack_timer.Stop();
}
if (ssl->d1->retransmit_timer.IsExpired(now)) {
any_timer_expired = true;
ssl->d1->sending_flight = true;
ssl->d1->retransmit_timer.Stop();
ssl->d1->num_timeouts++;
// Reduce MTU after 2 unsuccessful retransmissions.
if (ssl->d1->num_timeouts > DTLS1_MTU_TIMEOUTS &&
!(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
long mtu = BIO_ctrl(ssl->wbio.get(), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
nullptr);
if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {
ssl->d1->mtu = (unsigned)mtu;
}
}
}
if (!any_timer_expired) {
return 0;
}
return dtls1_flush(ssl);
}