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// Copyright (c) 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/quic/quic_client_session_cache.h"
#include "base/time/clock.h"
#include "base/time/default_clock.h"
namespace net {
namespace {
const size_t kDefaultMaxEntries = 1024;
// Returns false if the SSL |session| doesn't exist or it is expired at |now|.
bool IsValid(SSL_SESSION* session, time_t now) {
if (!session)
return false;
if (now < 0)
return false;
uint64_t now_u64 = static_cast<uint64_t>(now);
// now_u64 may be slightly behind because of differences in how
// time is calculated at this layer versus BoringSSL.
// Add a second of wiggle room to account for this.
return !(now_u64 < SSL_SESSION_get_time(session) - 1 ||
now_u64 >= SSL_SESSION_get_time(session) +
SSL_SESSION_get_timeout(session));
}
bool DoApplicationStatesMatch(const quic::ApplicationState* state,
quic::ApplicationState* other) {
if ((state && !other) || (!state && other))
return false;
if ((!state && !other) || *state == *other)
return true;
return false;
}
} // namespace
QuicClientSessionCache::QuicClientSessionCache()
: QuicClientSessionCache(kDefaultMaxEntries) {}
QuicClientSessionCache::QuicClientSessionCache(size_t max_entries)
: clock_(base::DefaultClock::GetInstance()), cache_(max_entries) {
memory_pressure_listener_.reset(
new base::MemoryPressureListener(base::BindRepeating(
&QuicClientSessionCache::OnMemoryPressure, base::Unretained(this))));
}
QuicClientSessionCache::~QuicClientSessionCache() {
Flush();
}
void QuicClientSessionCache::Insert(
const quic::QuicServerId& server_id,
bssl::UniquePtr<SSL_SESSION> session,
const quic::TransportParameters& params,
const quic::ApplicationState* application_state) {
DCHECK(session) << "TLS session is not inserted into client cache.";
auto iter = cache_.Get(server_id);
if (iter == cache_.end()) {
CreateAndInsertEntry(server_id, std::move(session), params,
application_state);
return;
}
DCHECK(iter->second.params);
// The states are both the same, so only need to insert sessions.
if (params == *iter->second.params &&
DoApplicationStatesMatch(application_state,
iter->second.application_state.get())) {
iter->second.PushSession(std::move(session));
return;
}
// Erase the existing entry because this Insert call must come from a
// different QUIC session.
cache_.Erase(iter);
CreateAndInsertEntry(server_id, std::move(session), params,
application_state);
}
std::unique_ptr<quic::QuicResumptionState> QuicClientSessionCache::Lookup(
const quic::QuicServerId& server_id,
const SSL_CTX* /*ctx*/) {
auto iter = cache_.Get(server_id);
if (iter == cache_.end())
return nullptr;
time_t now = clock_->Now().ToTimeT();
if (!IsValid(iter->second.PeekSession(), now)) {
cache_.Erase(iter);
return nullptr;
}
auto state = std::make_unique<quic::QuicResumptionState>();
state->tls_session = iter->second.PopSession();
state->transport_params = iter->second.params.get();
state->application_state = iter->second.application_state.get();
return state;
}
void QuicClientSessionCache::FlushInvalidEntries() {
time_t now = clock_->Now().ToTimeT();
auto iter = cache_.begin();
while (iter != cache_.end()) {
if (!IsValid(iter->second.PeekSession(), now)) {
iter = cache_.Erase(iter);
} else {
++iter;
}
}
}
void QuicClientSessionCache::OnMemoryPressure(
base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
switch (memory_pressure_level) {
case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE:
break;
case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE:
FlushInvalidEntries();
break;
case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL:
Flush();
break;
}
}
void QuicClientSessionCache::Flush() {
cache_.Clear();
}
void QuicClientSessionCache::CreateAndInsertEntry(
const quic::QuicServerId& server_id,
bssl::UniquePtr<SSL_SESSION> session,
const quic::TransportParameters& params,
const quic::ApplicationState* application_state) {
Entry entry;
entry.PushSession(std::move(session));
entry.params = std::make_unique<quic::TransportParameters>(params);
if (application_state) {
entry.application_state =
std::make_unique<quic::ApplicationState>(*application_state);
}
cache_.Put(server_id, std::move(entry));
}
QuicClientSessionCache::Entry::Entry() = default;
QuicClientSessionCache::Entry::Entry(Entry&&) = default;
QuicClientSessionCache::Entry::~Entry() = default;
void QuicClientSessionCache::Entry::PushSession(
bssl::UniquePtr<SSL_SESSION> session) {
if (sessions[0] != nullptr) {
sessions[1] = std::move(sessions[0]);
}
sessions[0] = std::move(session);
}
bssl::UniquePtr<SSL_SESSION> QuicClientSessionCache::Entry::PopSession() {
if (sessions[0] == nullptr)
return nullptr;
bssl::UniquePtr<SSL_SESSION> session = std::move(sessions[0]);
sessions[0] = std::move(sessions[1]);
sessions[1] = nullptr;
return session;
}
SSL_SESSION* QuicClientSessionCache::Entry::PeekSession() {
return sessions[0].get();
}
} // namespace net
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