60 lines
2.1 KiB
C
60 lines
2.1 KiB
C
/*
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* Global constants file.
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* Copyright (C) 2023 Brett Terpstra, Et al
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#ifndef INSANE_DNS_CONSTANTS_H
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#define INSANE_DNS_CONSTANTS_H
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/*
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* --------------------------------------------
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* | Magic Number Constants |
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* --------------------------------------------
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*/
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static constexpr size_t PACKET_BUFFER_SIZE = 65535;
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/*
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* These structs are used in combination with templates to create polymorphism between the UDP and TCP implementation.
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* this design decision has significantly reduced the code reuse while not introducing any runtime overhead.
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* The data set within these structures are specific to the protocol they implement. UDP is exactly as specified in the RFC spec
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* TCP is what I observed from wireshark (+2 byte offset)
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*/
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struct DNS_UDP_INFO_t
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{
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/** DNS header data offset. This is the first byte that isn't a header value (should be question label length octet) */
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size_t HEADER_END = 12;
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/** DNS questions count data offset. In the standard header this is 4 bytes in */
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size_t QUESTIONS_BEGIN = 4;
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/** DNS answer count data offset. */
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size_t ANSWERS_BEGIN = 6;
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};
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/*
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* The TCP version appears to use a 2 byte unsigned short to represent length. This struct accounts for that.
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*/
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struct DNS_TCP_INFO_t
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{
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size_t HEADER_END = 14;
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size_t QUESTIONS_BEGIN = 6;
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size_t ANSWERS_BEGIN = 8;
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};
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static constexpr DNS_UDP_INFO_t DNS_UDP_INFO;
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static constexpr DNS_TCP_INFO_t DNS_TCP_INFO;
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#endif //INSANE_DNS_CONSTANTS_H
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