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/*
* Copyright (C) 2019 Igalia S.L.
*
* 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 APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 "config.h"
#include "DNSCache.h"
#include <wtf/glib/RunLoopSourcePriority.h>
namespace WebKit {
static const Seconds expireInterval = 60_s;
static const unsigned maxCacheSize = 400;
Ref<DNSCache> DNSCache::create()
{
return adoptRef(*new DNSCache);
}
DNSCache::DNSCache()
: m_expiredTimer(RunLoop::main(), this, &DNSCache::removeExpiredResponsesFired)
{
m_expiredTimer.setPriority(RunLoopSourcePriority::ReleaseUnusedResourcesTimer);
}
DNSCache::DNSCacheMap& DNSCache::mapForType(Type type)
{
switch (type) {
case Type::Default:
return m_dnsMap;
case Type::IPv4Only:
return m_ipv4Map;
case Type::IPv6Only:
return m_ipv6Map;
}
RELEASE_ASSERT_NOT_REACHED();
return m_dnsMap;
}
std::optional<Vector<GRefPtr<GInetAddress>>> DNSCache::lookup(const CString& host, Type type)
{
Locker locker { m_lock };
auto& map = mapForType(type);
auto it = map.find(host);
if (it == map.end())
return std::nullopt;
auto& response = it->value;
if (response.expirationTime <= MonotonicTime::now()) {
map.remove(it);
return std::nullopt;
}
return response.addressList;
}
void DNSCache::update(const CString& host, Vector<GRefPtr<GInetAddress>>&& addressList, Type type)
{
Locker locker { m_lock };
auto& map = mapForType(type);
CachedResponse response = { WTFMove(addressList), MonotonicTime::now() + expireInterval };
auto addResult = map.set(host, WTFMove(response));
if (addResult.isNewEntry)
pruneResponsesInMap(map);
m_expiredTimer.startOneShot(expireInterval);
}
void DNSCache::removeExpiredResponsesInMap(DNSCacheMap& map)
{
map.removeIf([now = MonotonicTime::now()](auto& entry) {
return entry.value.expirationTime <= now;
});
}
void DNSCache::pruneResponsesInMap(DNSCacheMap& map)
{
if (map.size() <= maxCacheSize)
return;
// First try to remove expired responses.
removeExpiredResponsesInMap(map);
if (map.size() <= maxCacheSize)
return;
Vector<CString> keys = copyToVector(map.keys());
std::sort(keys.begin(), keys.end(), [&map](const CString& a, const CString& b) {
return map.get(a).expirationTime < map.get(b).expirationTime;
});
unsigned responsesToRemoveCount = keys.size() - maxCacheSize;
for (unsigned i = 0; i < responsesToRemoveCount; ++i)
map.remove(keys[i]);
}
void DNSCache::removeExpiredResponsesFired()
{
Locker locker { m_lock };
removeExpiredResponsesInMap(m_dnsMap);
removeExpiredResponsesInMap(m_ipv4Map);
removeExpiredResponsesInMap(m_ipv6Map);
}
void DNSCache::clear()
{
Locker locker { m_lock };
m_dnsMap.clear();
m_ipv4Map.clear();
m_ipv6Map.clear();
}
} // namespace WebKit
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