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6b3ed6c75b
Prevent public reflection of the only internally used 'init_sum' argument in 'uint16_t internet_checksum(...)' that, in addition, added a default value to the function interface. Ref #4555
58 lines
1.9 KiB
C++
58 lines
1.9 KiB
C++
/*
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* \brief Computing the Internet Checksum (conforms to RFC 1071)
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* \author Martin Stein
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* \date 2018-03-23
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*/
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/*
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* Copyright (C) 2018 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 _NET__INTERNET_CHECKSUM_H_
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#define _NET__INTERNET_CHECKSUM_H_
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/* Genode includes */
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#include <net/ipv4.h>
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#include <base/stdint.h>
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namespace Net {
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/**
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* This struct helps avoiding the following compiler warning when using
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* the internet checksum functions on packet classes (like
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* Net::Ipv4_packet):
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*
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* warning: converting a packed ‘Net::[PACKET_CLASS]’ pointer
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* (alignment 1) to a ‘const uint16_t’ {aka ‘const short
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* unsigned int’} pointer (alignment 2) may result in an
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* unaligned pointer value
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*
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* Apparently, the 'packed' attribute normally used on packet classes sets
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* the alignment of the packet class to 1. However, for the purpose of the
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* internet-checksum functions, we can assume that the packet data has no
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* alignment. This is expressed by casting the packet-object pointer to a
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* Packed_uint16 pointer instead of a uint16_t pointer.
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*/
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struct Packed_uint16
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{
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Genode::uint16_t value;
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} __attribute__((packed));
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Genode::uint16_t internet_checksum(Packed_uint16 const *data_ptr,
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Genode::size_t data_sz);
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Genode::uint16_t
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internet_checksum_pseudo_ip(Packed_uint16 const *data_ptr,
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Genode::size_t data_sz,
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Genode::uint16_t ip_data_sz_be,
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Ipv4_packet::Protocol ip_prot,
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Ipv4_address &ip_src,
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Ipv4_address &ip_dst);
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}
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#endif /* _NET__INTERNET_CHECKSUM_H_ */
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