genode/repos/os/include/net/tcp.h
Martin Stein 6b55790e73 net: use generic internet checksum
This reduces the redundant implementations of checksum calculation to
one generic implementation, makes the checksum interface conform over
all protocols, and brings performance optimizations. For instance,
the checksum is now calculated directly in big endian which saves us
most of the previously done byte-re-ordering.

Issue #2775
2018-05-03 15:31:56 +02:00

114 lines
3.2 KiB
C++

/*
* \brief Transmission Control Protocol
* \author Martin Stein
* \date 2016-06-15
*/
/*
* Copyright (C) 2016-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _TCP_H_
#define _TCP_H_
/* Genode includes */
#include <base/exception.h>
#include <base/stdint.h>
#include <util/endian.h>
#include <net/ethernet.h>
#include <net/ipv4.h>
#include <util/register.h>
#include <net/port.h>
namespace Net
{
class Tcp_state;
class Tcp_packet;
}
/**
* Data layout of this class conforms to an TCP packet (RFC 768)
*/
class Net::Tcp_packet
{
private:
using uint8_t = Genode::uint8_t;
using uint16_t = Genode::uint16_t;
using uint32_t = Genode::uint32_t;
using size_t = Genode::size_t;
using Exception = Genode::Exception;
uint16_t _src_port;
uint16_t _dst_port;
uint32_t _seq_nr;
uint32_t _ack_nr;
unsigned _data_offset : 4;
unsigned _reserved : 3;
unsigned _flags_msb : 1;
uint8_t _flags_lsb;
uint16_t _window_size;
uint16_t _checksum;
uint16_t _urgent_ptr;
uint32_t _data[0];
struct Flags : Genode::Register<16>
{
struct Fin : Bitfield<0, 1> { };
struct Syn : Bitfield<1, 1> { };
struct Rst : Bitfield<2, 1> { };
struct Psh : Bitfield<3, 1> { };
struct Ack : Bitfield<4, 1> { };
struct Urg : Bitfield<5, 1> { };
struct Ece : Bitfield<6, 1> { };
struct Crw : Bitfield<7, 1> { };
struct Ns : Bitfield<8, 1> { };
};
public:
void update_checksum(Ipv4_address ip_src,
Ipv4_address ip_dst,
size_t tcp_size);
/***************
** Accessors **
***************/
Port src_port() const { return Port(host_to_big_endian(_src_port)); }
Port dst_port() const { return Port(host_to_big_endian(_dst_port)); }
uint32_t seq_nr() const { return host_to_big_endian(_seq_nr); }
uint32_t ack_nr() const { return host_to_big_endian(_ack_nr); }
uint8_t data_offset() const { return _data_offset; }
uint16_t flags() const { return _flags_lsb | _flags_msb << 8; }
uint16_t window_size() const { return host_to_big_endian(_window_size); }
uint16_t checksum() const { return host_to_big_endian(_checksum); }
uint16_t urgent_ptr() const { return host_to_big_endian(_urgent_ptr); }
bool ns() const { return Flags::Ns::get(flags()); };
bool ece() const { return Flags::Ece::get(flags()); };
bool crw() const { return Flags::Crw::get(flags()); };
bool fin() const { return Flags::Fin::get(flags()); };
bool syn() const { return Flags::Syn::get(flags()); };
bool rst() const { return Flags::Rst::get(flags()); };
bool psh() const { return Flags::Psh::get(flags()); };
bool ack() const { return Flags::Ack::get(flags()); };
bool urg() const { return Flags::Urg::get(flags()); };
void src_port(Port p) { _src_port = host_to_big_endian(p.value); }
void dst_port(Port p) { _dst_port = host_to_big_endian(p.value); }
/*********
** log **
*********/
void print(Genode::Output &output) const;
} __attribute__((packed));
#endif /* _TCP_H_ */