Insane_DNS/include/insane_dns/constants.h

59 lines
2.0 KiB
C

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