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/*
* Copyright (C) 2020 Apple Inc. 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 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 "STUNMessageParsing.h"
#if ENABLE(WEB_RTC) && USE(LIBWEBRTC)
#include <LibWebRTCMacros.h>
#include <webrtc/rtc_base/byte_order.h>
namespace WebCore {
namespace WebRTC {
static inline bool isStunMessage(uint16_t messageType)
{
// https://tools.ietf.org/html/rfc5389#section-6 for STUN messages.
// TURN messages start by the channel number which is constrained by https://tools.ietf.org/html/rfc5766#section-11.
return !(messageType & 0xC000);
}
std::optional<STUNMessageLengths> getSTUNOrTURNMessageLengths(const uint8_t* data, size_t size)
{
if (size < 4)
return { };
auto messageType = be16toh(*reinterpret_cast<const uint16_t*>(data));
auto messageLength = be16toh(*reinterpret_cast<const uint16_t*>(data + 2));
// STUN data message header is 20 bytes.
if (isStunMessage(messageType)) {
size_t length = 20 + messageLength;
return STUNMessageLengths { length, length };
}
// TURN data message header is 4 bytes plus padding bytes to get 4 bytes alignment as needed.
size_t length = 4 + messageLength;
size_t roundedLength = length % 4 ? (length + 4 - (length % 4)) : length;
return STUNMessageLengths { length, roundedLength };
}
static inline Vector<uint8_t> extractSTUNOrTURNMessages(Vector<uint8_t>&& buffered, const Function<void(const uint8_t* data, size_t size)>& processMessage)
{
auto* data = buffered.data();
size_t size = buffered.size();
while (true) {
auto lengths = getSTUNOrTURNMessageLengths(data, size);
if (!lengths || lengths->messageLengthWithPadding > size) {
if (!size)
return { };
std::memcpy(buffered.data(), data, size);
buffered.resize(size);
return WTFMove(buffered);
}
processMessage(data, lengths->messageLength);
data += lengths->messageLengthWithPadding;
size -= lengths->messageLengthWithPadding;
}
}
static inline Vector<uint8_t> extractDataMessages(Vector<uint8_t>&& buffered, const Function<void(const uint8_t* data, size_t size)>& processMessage)
{
constexpr size_t lengthFieldSize = 2; // number of bytes read by be16toh.
auto* data = buffered.data();
size_t size = buffered.size();
while (true) {
bool canReadLength = size >= lengthFieldSize;
size_t length = canReadLength ? be16toh(*reinterpret_cast<const uint16_t*>(data)) : 0;
if (!canReadLength || length > size - lengthFieldSize) {
if (!size)
return { };
std::memcpy(buffered.data(), data, size);
buffered.resize(size);
return WTFMove(buffered);
}
data += lengthFieldSize;
size -= lengthFieldSize;
processMessage(data, length);
data += length;
size -= length;
}
}
Vector<uint8_t> extractMessages(Vector<uint8_t>&& buffer, MessageType type, const Function<void(const uint8_t* data, size_t size)>& processMessage)
{
return type == MessageType::STUN ? extractSTUNOrTURNMessages(WTFMove(buffer), processMessage) : extractDataMessages(WTFMove(buffer), processMessage);
}
} // namespace WebRTC
} // namespace WebCore
#endif // ENABLE(WEB_RTC) && USE(LIBWEBRTC)
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