79 lines
2.6 KiB
C++
79 lines
2.6 KiB
C++
// 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/helpers/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)) {
|
|
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
|