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tdlib-fork/td/mtproto/Transport.h

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/mtproto/utils.h"
#include "td/utils/common.h"
#include "td/utils/int_types.h"
#include "td/utils/logging.h"
#include "td/utils/Slice.h"
#include "td/utils/Status.h"
#include "td/utils/UInt.h"
#include <tuple>
namespace td {
namespace mtproto {
class AuthKey;
#pragma pack(push, 4)
#if TD_MSVC
#pragma warning(push)
#pragma warning(disable : 4200)
#endif
struct CryptoHeader {
uint64 auth_key_id;
UInt128 message_key;
// encrypted part
uint64 salt;
uint64 session_id;
// It is weird to generate message_id and seq_no while writing a packet.
//
// uint64 message_id;
// uint32 seq_no;
// uint32 message_data_length;
uint8 data[0]; // use compiler extension
static size_t encrypted_header_size() {
return sizeof(salt) + sizeof(session_id);
}
uint8 *encrypt_begin() {
return reinterpret_cast<uint8 *>(&salt);
}
const uint8 *encrypt_begin() const {
return reinterpret_cast<const uint8 *>(&salt);
}
CryptoHeader() = delete;
CryptoHeader(const CryptoHeader &) = delete;
CryptoHeader(CryptoHeader &&) = delete;
CryptoHeader &operator=(const CryptoHeader &) = delete;
CryptoHeader &operator=(CryptoHeader &&) = delete;
~CryptoHeader() = delete;
};
struct CryptoPrefix {
uint64 message_id;
uint32 seq_no;
uint32 message_data_length;
};
struct EndToEndHeader {
uint64 auth_key_id;
UInt128 message_key;
// encrypted part
// uint32 message_data_length;
uint8 data[0]; // use compiler extension
static size_t encrypted_header_size() {
return 0;
}
uint8 *encrypt_begin() {
return reinterpret_cast<uint8 *>(&data);
}
const uint8 *encrypt_begin() const {
return reinterpret_cast<const uint8 *>(&data);
}
EndToEndHeader() = delete;
EndToEndHeader(const EndToEndHeader &) = delete;
EndToEndHeader(EndToEndHeader &&) = delete;
EndToEndHeader &operator=(const EndToEndHeader &) = delete;
EndToEndHeader &operator=(EndToEndHeader &&) = delete;
~EndToEndHeader() = delete;
};
struct EndToEndPrefix {
uint32 message_data_length;
};
struct NoCryptoHeader {
uint64 auth_key_id;
// message_id is removed from CryptoHeader. Should be removed from here too.
//
// int64 message_id;
// uint32 message_data_length;
uint8 data[0]; // use compiler extension
NoCryptoHeader() = delete;
NoCryptoHeader(const NoCryptoHeader &) = delete;
NoCryptoHeader(NoCryptoHeader &&) = delete;
NoCryptoHeader &operator=(const NoCryptoHeader &) = delete;
NoCryptoHeader &operator=(NoCryptoHeader &&) = delete;
~NoCryptoHeader() = delete;
};
#if TD_MSVC
#pragma warning(pop)
#endif
#pragma pack(pop)
struct PacketInfo {
enum { Common, EndToEnd } type = Common;
uint64 auth_key_id;
uint32 message_ack;
UInt128 message_key;
uint64 salt;
uint64 session_id;
uint64 message_id;
int32 seq_no;
int32 version = 1;
bool no_crypto_flag;
bool is_creator = false;
};
class Transport {
public:
class ReadResult {
public:
enum Type { Packet, Nop, Error, Quickack };
static ReadResult make_nop() {
return {};
}
static ReadResult make_error(int32 error_code) {
ReadResult res;
res.type_ = Error;
res.error_code_ = error_code;
return res;
}
static ReadResult make_packet(MutableSlice packet) {
CHECK(!packet.empty());
ReadResult res;
res.type_ = Packet;
res.packet_ = packet;
return res;
}
static ReadResult make_quick_ack(uint32 quick_ack) {
ReadResult res;
res.type_ = Quickack;
res.quick_ack_ = quick_ack;
return res;
}
Type type() const {
return type_;
}
MutableSlice packet() const {
CHECK(type_ == Packet);
return packet_;
}
uint32 quick_ack() const {
CHECK(type_ == Quickack);
return quick_ack_;
}
int32 error() const {
CHECK(type_ == Error);
return error_code_;
}
private:
Type type_ = Nop;
MutableSlice packet_;
int32 error_code_ = 0;
uint32 quick_ack_ = 0;
};
static Result<uint64> read_auth_key_id(Slice message);
// Reads mtproto packet from [message] and saves into [data].
// If message is encrypted, [auth_key] is used.
// Decryption and unpacking is made inplace, so [data] will be subslice of [message].
// Returns size of mtproto packet.
// If dest.size() >= size, the packet is also written into [dest].
// If auth_key is nonempty, encryption will be used.
static Result<ReadResult> read(MutableSlice message, const AuthKey &auth_key, PacketInfo *info) TD_WARN_UNUSED_RESULT;
static size_t write(const Storer &storer, const AuthKey &auth_key, PacketInfo *info,
MutableSlice dest = MutableSlice());
private:
template <class HeaderT>
static std::tuple<uint32, UInt128> calc_message_ack_and_key(const HeaderT &head, size_t data_size);
static std::tuple<uint32, UInt128> calc_message_key2(const AuthKey &auth_key, int X, Slice to_encrypt);
template <class HeaderT>
static size_t calc_crypto_size(size_t data_size);
template <class HeaderT>
static size_t calc_crypto_size2(size_t data_size);
static size_t calc_no_crypto_size(size_t data_size);
static Status read_no_crypto(MutableSlice message, PacketInfo *info, MutableSlice *data) TD_WARN_UNUSED_RESULT;
static Status read_crypto(MutableSlice message, const AuthKey &auth_key, PacketInfo *info,
MutableSlice *data) TD_WARN_UNUSED_RESULT;
static Status read_e2e_crypto(MutableSlice message, const AuthKey &auth_key, PacketInfo *info,
MutableSlice *data) TD_WARN_UNUSED_RESULT;
template <class HeaderT, class PrefixT>
static Status read_crypto_impl(int X, MutableSlice message, const AuthKey &auth_key, HeaderT **header_ptr,
PrefixT **prefix_ptr, MutableSlice *data, PacketInfo *info) TD_WARN_UNUSED_RESULT;
static size_t write_no_crypto(const Storer &storer, PacketInfo *info, MutableSlice dest);
static size_t write_crypto(const Storer &storer, const AuthKey &auth_key, PacketInfo *info, MutableSlice dest);
static size_t write_e2e_crypto(const Storer &storer, const AuthKey &auth_key, PacketInfo *info, MutableSlice dest);
template <class HeaderT>
static void write_crypto_impl(int X, const Storer &storer, const AuthKey &auth_key, PacketInfo *info, HeaderT *header,
size_t data_size);
};
} // namespace mtproto
} // namespace td