diff options
Diffstat (limited to 'src/Protocol/ProtocolRecognizer.cpp')
| -rw-r--r-- | src/Protocol/ProtocolRecognizer.cpp | 120 |
1 files changed, 47 insertions, 73 deletions
diff --git a/src/Protocol/ProtocolRecognizer.cpp b/src/Protocol/ProtocolRecognizer.cpp index dc6b93b01..3af4f9654 100644 --- a/src/Protocol/ProtocolRecognizer.cpp +++ b/src/Protocol/ProtocolRecognizer.cpp @@ -25,18 +25,6 @@ -struct UnsupportedButPingableProtocolException : public std::runtime_error -{ - explicit UnsupportedButPingableProtocolException() : - std::runtime_error("") - { - } -}; - - - - - struct TriedToJoinWithUnsupportedProtocolException : public std::runtime_error { explicit TriedToJoinWithUnsupportedProtocolException(const std::string & a_Message) : @@ -90,31 +78,44 @@ AString cMultiVersionProtocol::GetVersionTextFromInt(cProtocol::Version a_Protoc void cMultiVersionProtocol::HandleIncomingDataInRecognitionStage(cClientHandle & a_Client, std::string_view a_Data) { - // We read more than the handshake packet here, oh well. + // NOTE: If a new protocol is added or an old one is removed, adjust MCS_CLIENT_VERSIONS and MCS_PROTOCOL_VERSIONS macros in the header file + + /* Write all incoming data unmodified into m_Buffer. + Writing everything is always okay to do: + 1. We can be sure protocol encryption hasn't started yet since m_Protocol hasn't been called, hence no decryption needs to take place + 2. The extra data are processed at the end of this function */ if (!m_Buffer.Write(a_Data.data(), a_Data.size())) { - a_Client.Kick("Your client sent too much data; please try again later."); + a_Client.PacketBufferFull(); return; } - try - { - // Note that a_Data is assigned to a subview containing the data to pass to m_Protocol or UnsupportedPing + // TODO: recover from git history + // Unlengthed protocol, ... - TryRecognizeProtocol(a_Client, a_Data); - if (m_Protocol == nullptr) - { - m_Buffer.ResetRead(); - return; - } + // Lengthed protocol, try if it has the entire initial handshake packet: + if ( + UInt32 PacketLen; - // The protocol recogniser succesfully identified, switch mode: - HandleIncomingData = [this](cClientHandle &, const std::string_view a_In) - { - m_Protocol->DataReceived(m_Buffer, a_In.data(), a_In.size()); - }; + // If not enough bytes for the packet length, keep waiting + !m_Buffer.ReadVarInt(PacketLen) || + + // If not enough bytes for the packet, keep waiting + // (More of a sanity check to make sure no one tries anything funny, since ReadXXX can wait for data themselves) + !m_Buffer.CanReadBytes(PacketLen) + ) + { + m_Buffer.ResetRead(); + return; } - catch (const UnsupportedButPingableProtocolException &) + + /* Figure out the client's version. + 1. m_Protocol != nullptr: the protocol is supported and we have a handler + 2. m_Protocol == nullptr: the protocol is unsupported, handling is a special case done by ourselves + 3. Exception: the data sent were garbage, the client handle deals with it by disconnecting */ + m_Protocol = TryRecognizeLengthedProtocol(a_Client, a_Data); + + if (m_Protocol == nullptr) { // Got a server list ping for an unrecognised version, // switch into responding to unknown protocols mode: @@ -123,9 +124,17 @@ void cMultiVersionProtocol::HandleIncomingDataInRecognitionStage(cClientHandle & HandleIncomingDataInOldPingResponseStage(a_Clyent, a_In); }; } + else + { + // The protocol recogniser succesfully identified, switch mode: + HandleIncomingData = [this](cClientHandle &, const std::string_view a_In) + { + m_Protocol->DataReceived(m_Buffer, a_In.data(), a_In.size()); + }; + } - // Explicitly process any remaining data with the new handler: - HandleIncomingData(a_Client, a_Data); + // Explicitly process any remaining data (already written to m_Buffer) with the new handler: + HandleIncomingData(a_Client, {}); } @@ -136,7 +145,7 @@ void cMultiVersionProtocol::HandleIncomingDataInOldPingResponseStage(cClientHand { if (!m_Buffer.Write(a_Data.data(), a_Data.size())) { - a_Client.Kick("Server list ping failed, too much data."); + a_Client.PacketBufferFull(); return; } @@ -170,7 +179,7 @@ void cMultiVersionProtocol::HandleIncomingDataInOldPingResponseStage(cClientHand } else { - a_Client.Kick("Server list ping failed, unrecognized packet."); + a_Client.PacketUnknown(PacketID); return; } @@ -206,34 +215,7 @@ void cMultiVersionProtocol::SendDisconnect(cClientHandle & a_Client, const AStri -void cMultiVersionProtocol::TryRecognizeProtocol(cClientHandle & a_Client, std::string_view & a_Data) -{ - // NOTE: If a new protocol is added or an old one is removed, adjust MCS_CLIENT_VERSIONS and MCS_PROTOCOL_VERSIONS macros in the header file - - // Lengthed protocol, try if it has the entire initial handshake packet: - UInt32 PacketLen; - if (!m_Buffer.ReadVarInt(PacketLen)) - { - // Not enough bytes for the packet length, keep waiting - return; - } - - if (!m_Buffer.CanReadBytes(PacketLen)) - { - // Not enough bytes for the packet, keep waiting - // More of a sanity check to make sure no one tries anything funny (since ReadXXX can wait for data themselves): - return; - } - - m_Protocol = TryRecognizeLengthedProtocol(a_Client, a_Data); - ASSERT(m_Protocol != nullptr); -} - - - - - -std::unique_ptr<cProtocol> cMultiVersionProtocol::TryRecognizeLengthedProtocol(cClientHandle & a_Client, std::string_view & a_Data) +std::unique_ptr<cProtocol> cMultiVersionProtocol::TryRecognizeLengthedProtocol(cClientHandle & a_Client, const std::string_view a_Data) { UInt32 PacketType; UInt32 ProtocolVersion; @@ -243,8 +225,8 @@ std::unique_ptr<cProtocol> cMultiVersionProtocol::TryRecognizeLengthedProtocol(c if (!m_Buffer.ReadVarInt(PacketType) || (PacketType != 0x00)) { - // Not an initial handshake packet, we don't know how to talk to them - LOGINFO("Client \"%s\" uses an unsupported protocol (lengthed, initial packet %u)", + // Not an initial handshake packet, we don't know how to talk to them: + LOGD("Client \"%s\" uses an unsupported protocol (lengthed, initial packet %u)", a_Client.GetIPString().c_str(), PacketType ); @@ -277,15 +259,6 @@ std::unique_ptr<cProtocol> cMultiVersionProtocol::TryRecognizeLengthedProtocol(c // TODO: this should be a protocol property, not ClientHandle: a_Client.SetProtocolVersion(ProtocolVersion); - // The protocol has just been recognized, advance data start - // to after the handshake and leave the rest to the protocol: - a_Data = a_Data.substr(m_Buffer.GetUsedSpace() - m_Buffer.GetReadableSpace()); - - // We read more than we can handle, purge the rest: - [[maybe_unused]] const bool Success = - m_Buffer.SkipRead(m_Buffer.GetReadableSpace()); - ASSERT(Success); - // All good, eat up the data: m_Buffer.CommitRead(); @@ -319,7 +292,8 @@ std::unique_ptr<cProtocol> cMultiVersionProtocol::TryRecognizeLengthedProtocol(c ); } - throw UnsupportedButPingableProtocolException(); + // No cProtocol can handle the client: + return nullptr; } } } |