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author | bunnei <bunneidev@gmail.com> | 2020-01-24 02:18:47 +0100 |
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committer | GitHub <noreply@github.com> | 2020-01-24 02:18:47 +0100 |
commit | deb97f6a8e48c17f8e16efadc24872a860d529a7 (patch) | |
tree | 79ca6164fcb03783bc19f1ec557cacdf0b3fc539 /src/input_common/udp/protocol.cpp | |
parent | Merge pull request #3341 from bunnei/time-posix-myrule (diff) | |
parent | Replace GetString with Get function (diff) | |
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Diffstat (limited to 'src/input_common/udp/protocol.cpp')
-rw-r--r-- | src/input_common/udp/protocol.cpp | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/src/input_common/udp/protocol.cpp b/src/input_common/udp/protocol.cpp new file mode 100644 index 000000000..a982ac49d --- /dev/null +++ b/src/input_common/udp/protocol.cpp @@ -0,0 +1,79 @@ +// Copyright 2018 Citra Emulator Project +// Licensed under GPLv2 or any later version +// Refer to the license.txt file included. + +#include <cstddef> +#include <cstring> +#include "common/logging/log.h" +#include "input_common/udp/protocol.h" + +namespace InputCommon::CemuhookUDP { + +static constexpr std::size_t GetSizeOfResponseType(Type t) { + switch (t) { + case Type::Version: + return sizeof(Response::Version); + case Type::PortInfo: + return sizeof(Response::PortInfo); + case Type::PadData: + return sizeof(Response::PadData); + } + return 0; +} + +namespace Response { + +/** + * Returns Type if the packet is valid, else none + * + * Note: Modifies the buffer to zero out the crc (since thats the easiest way to check without + * copying the buffer) + */ +std::optional<Type> Validate(u8* data, std::size_t size) { + if (size < sizeof(Header)) { + LOG_DEBUG(Input, "Invalid UDP packet received"); + return std::nullopt; + } + Header header{}; + std::memcpy(&header, data, sizeof(Header)); + if (header.magic != SERVER_MAGIC) { + LOG_ERROR(Input, "UDP Packet has an unexpected magic value"); + return std::nullopt; + } + if (header.protocol_version != PROTOCOL_VERSION) { + LOG_ERROR(Input, "UDP Packet protocol mismatch"); + return std::nullopt; + } + if (header.type < Type::Version || header.type > Type::PadData) { + LOG_ERROR(Input, "UDP Packet is an unknown type"); + return std::nullopt; + } + + // Packet size must equal sizeof(Header) + sizeof(Data) + // and also verify that the packet info mentions the correct size. Since the spec includes the + // type of the packet as part of the data, we need to include it in size calculations here + // ie: payload_length == sizeof(T) + sizeof(Type) + const std::size_t data_len = GetSizeOfResponseType(header.type); + if (header.payload_length != data_len + sizeof(Type) || size < data_len + sizeof(Header)) { + LOG_ERROR( + Input, + "UDP Packet payload length doesn't match. Received: {} PayloadLength: {} Expected: {}", + size, header.payload_length, data_len + sizeof(Type)); + return std::nullopt; + } + + const u32 crc32 = header.crc; + boost::crc_32_type result; + // zero out the crc in the buffer and then run the crc against it + std::memset(&data[offsetof(Header, crc)], 0, sizeof(u32_le)); + + result.process_bytes(data, data_len + sizeof(Header)); + if (crc32 != result.checksum()) { + LOG_ERROR(Input, "UDP Packet CRC check failed. Offset: {}", offsetof(Header, crc)); + return std::nullopt; + } + return header.type; +} +} // namespace Response + +} // namespace InputCommon::CemuhookUDP |