64 lines
1.9 KiB
C++
64 lines
1.9 KiB
C++
#ifndef IPV4HEADER_H
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#define IPV4HEADER_H
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#include <istream>
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#include "asio.h"
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namespace Network {
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namespace Internal {
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class Ipv4Header
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{
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public:
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Ipv4Header() { std::fill(rep_, rep_ + sizeof(rep_), 0); }
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unsigned char version() const { return (rep_[0] >> 4) & 0xF; }
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unsigned short header_length() const { return (rep_[0] & 0xF) * 4; }
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unsigned char type_of_service() const { return rep_[1]; }
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unsigned short total_length() const { return decode(2, 3); }
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unsigned short identification() const { return decode(4, 5); }
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bool dont_fragment() const { return (rep_[6] & 0x40) != 0; }
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bool more_fragments() const { return (rep_[6] & 0x20) != 0; }
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unsigned short fragment_offset() const { return decode(6, 7) & 0x1FFF; }
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unsigned int time_to_live() const { return rep_[8]; }
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unsigned char protocol() const { return rep_[9]; }
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unsigned short header_checksum() const { return decode(10, 11); }
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asio::ip::address_v4 source_address() const
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{
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asio::ip::address_v4::bytes_type bytes = { { rep_[12], rep_[13], rep_[14], rep_[15] } };
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return asio::ip::address_v4(bytes);
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}
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asio::ip::address_v4 destination_address() const
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{
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asio::ip::address_v4::bytes_type bytes = { { rep_[16], rep_[17], rep_[18], rep_[19] } };
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return asio::ip::address_v4(bytes);
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}
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friend std::istream& operator>>(std::istream& is, Ipv4Header& header)
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{
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is.read(reinterpret_cast<char*>(header.rep_), 20);
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if (header.version() != 4)
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is.setstate(std::ios::failbit);
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std::streamsize options_length = header.header_length() - 20;
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if (options_length < 0 || options_length > 40)
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is.setstate(std::ios::failbit);
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else
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is.read(reinterpret_cast<char*>(header.rep_) + 20, options_length);
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return is;
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}
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private:
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unsigned short decode(int a, int b) const
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{ return (rep_[a] << 8) + rep_[b]; }
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unsigned char rep_[60];
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};
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} // namespace Internal
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} // namespace Network
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#endif // IPV4HEADER_H
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