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9a37ccfe29
The checksums for forwarded/routed UDP, TCP and ICMP, used to be always re-calculated from scratch in the NIC router although the router changes only a few packet fields. This commit replaces the old approach whereever sensible with an algorithm for incremental checksum updates suggested in RFC 1071. The goal is to improve router performance. Ref #4555
117 lines
3.4 KiB
C++
117 lines
3.4 KiB
C++
/*
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* \brief Transmission Control Protocol
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* \author Martin Stein
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* \date 2016-06-15
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*/
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/*
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* Copyright (C) 2016-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _TCP_H_
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#define _TCP_H_
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/* Genode includes */
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#include <base/exception.h>
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#include <base/stdint.h>
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#include <util/endian.h>
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#include <net/ethernet.h>
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#include <net/ipv4.h>
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#include <util/register.h>
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#include <net/port.h>
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namespace Net
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{
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class Tcp_state;
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class Tcp_packet;
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}
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/**
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* Data layout of this class conforms to an TCP packet (RFC 768)
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*/
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class Net::Tcp_packet
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{
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private:
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using uint8_t = Genode::uint8_t;
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using uint16_t = Genode::uint16_t;
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using uint32_t = Genode::uint32_t;
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using size_t = Genode::size_t;
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using Exception = Genode::Exception;
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uint16_t _src_port;
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uint16_t _dst_port;
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uint32_t _seq_nr;
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uint32_t _ack_nr;
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uint16_t _flags;
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uint16_t _window_size;
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uint16_t _checksum;
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uint16_t _urgent_ptr;
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uint32_t _data[0];
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struct Flags : Genode::Register<16>
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{
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struct Fin : Bitfield<0, 1> { };
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struct Syn : Bitfield<1, 1> { };
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struct Rst : Bitfield<2, 1> { };
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struct Psh : Bitfield<3, 1> { };
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struct Ack : Bitfield<4, 1> { };
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struct Urg : Bitfield<5, 1> { };
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struct Ece : Bitfield<6, 1> { };
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struct Cwr : Bitfield<7, 1> { };
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struct Ns : Bitfield<8, 1> { };
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struct Data_offset : Bitfield<12, 4> { };
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};
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public:
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void update_checksum(Ipv4_address ip_src,
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Ipv4_address ip_dst,
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size_t tcp_size);
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void update_checksum(Internet_checksum_diff const &icd);
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/***************
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** Accessors **
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***************/
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Port src_port() const { return Port(host_to_big_endian(_src_port)); }
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Port dst_port() const { return Port(host_to_big_endian(_dst_port)); }
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uint32_t seq_nr() const { return host_to_big_endian(_seq_nr); }
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uint32_t ack_nr() const { return host_to_big_endian(_ack_nr); }
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uint8_t data_offset() const { return Flags::Data_offset::get(flags()); }
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uint16_t flags() const { return host_to_big_endian(_flags); }
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uint16_t window_size() const { return host_to_big_endian(_window_size); }
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uint16_t checksum() const { return host_to_big_endian(_checksum); }
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uint16_t urgent_ptr() const { return host_to_big_endian(_urgent_ptr); }
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bool ns() const { return Flags::Ns::get(flags()); };
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bool ece() const { return Flags::Ece::get(flags()); };
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bool cwr() const { return Flags::Cwr::get(flags()); };
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bool fin() const { return Flags::Fin::get(flags()); };
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bool syn() const { return Flags::Syn::get(flags()); };
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bool rst() const { return Flags::Rst::get(flags()); };
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bool psh() const { return Flags::Psh::get(flags()); };
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bool ack() const { return Flags::Ack::get(flags()); };
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bool urg() const { return Flags::Urg::get(flags()); };
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void src_port(Port p) { _src_port = host_to_big_endian(p.value); }
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void dst_port(Port p) { _dst_port = host_to_big_endian(p.value); }
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void src_port(Port p, Internet_checksum_diff &icd);
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void dst_port(Port p, Internet_checksum_diff &icd);
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/*********
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** log **
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*********/
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void print(Genode::Output &output) const;
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} __attribute__((packed));
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#endif /* _TCP_H_ */
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