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114 lines
5.4 KiB
114 lines
5.4 KiB
#ifndef HEADER_CARES_DNS_H |
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#define HEADER_CARES_DNS_H |
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/* Copyright 1998, 2011 by the Massachusetts Institute of Technology. |
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* |
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* Permission to use, copy, modify, and distribute this |
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* software and its documentation for any purpose and without |
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* fee is hereby granted, provided that the above copyright |
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* notice appear in all copies and that both that copyright |
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* notice and this permission notice appear in supporting |
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* documentation, and that the name of M.I.T. not be used in |
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* advertising or publicity pertaining to distribution of the |
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* software without specific, written prior permission. |
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* M.I.T. makes no representations about the suitability of |
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* this software for any purpose. It is provided "as is" |
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* without express or implied warranty. |
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* |
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* SPDX-License-Identifier: MIT |
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*/ |
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/* |
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* NOTE TO INTEGRATORS: |
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* |
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* This header is made public due to legacy projects relying on it. |
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* Please do not use the macros within this header, or include this |
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* header in your project as it may be removed in the future. |
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*/ |
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/* |
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* Macro DNS__16BIT reads a network short (16 bit) given in network |
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* byte order, and returns its value as an unsigned short. |
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*/ |
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#define DNS__16BIT(p) ((unsigned short)((unsigned int) 0xffff & \ |
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(((unsigned int)((unsigned char)(p)[0]) << 8U) | \ |
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((unsigned int)((unsigned char)(p)[1]))))) |
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/* |
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* Macro DNS__32BIT reads a network long (32 bit) given in network |
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* byte order, and returns its value as an unsigned int. |
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*/ |
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#define DNS__32BIT(p) ((unsigned int) \ |
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(((unsigned int)((unsigned char)(p)[0]) << 24U) | \ |
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((unsigned int)((unsigned char)(p)[1]) << 16U) | \ |
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((unsigned int)((unsigned char)(p)[2]) << 8U) | \ |
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((unsigned int)((unsigned char)(p)[3])))) |
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#define DNS__SET16BIT(p, v) (((p)[0] = (unsigned char)(((v) >> 8) & 0xff)), \ |
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((p)[1] = (unsigned char)((v) & 0xff))) |
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#define DNS__SET32BIT(p, v) (((p)[0] = (unsigned char)(((v) >> 24) & 0xff)), \ |
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((p)[1] = (unsigned char)(((v) >> 16) & 0xff)), \ |
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((p)[2] = (unsigned char)(((v) >> 8) & 0xff)), \ |
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((p)[3] = (unsigned char)((v) & 0xff))) |
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#if 0 |
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/* we cannot use this approach on systems where we can't access 16/32 bit |
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data on un-aligned addresses */ |
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#define DNS__16BIT(p) ntohs(*(unsigned short*)(p)) |
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#define DNS__32BIT(p) ntohl(*(unsigned long*)(p)) |
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#define DNS__SET16BIT(p, v) *(unsigned short*)(p) = htons(v) |
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#define DNS__SET32BIT(p, v) *(unsigned long*)(p) = htonl(v) |
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#endif |
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/* Macros for parsing a DNS header */ |
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#define DNS_HEADER_QID(h) DNS__16BIT(h) |
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#define DNS_HEADER_QR(h) (((h)[2] >> 7) & 0x1) |
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#define DNS_HEADER_OPCODE(h) (((h)[2] >> 3) & 0xf) |
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#define DNS_HEADER_AA(h) (((h)[2] >> 2) & 0x1) |
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#define DNS_HEADER_TC(h) (((h)[2] >> 1) & 0x1) |
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#define DNS_HEADER_RD(h) ((h)[2] & 0x1) |
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#define DNS_HEADER_RA(h) (((h)[3] >> 7) & 0x1) |
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#define DNS_HEADER_Z(h) (((h)[3] >> 4) & 0x7) |
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#define DNS_HEADER_RCODE(h) ((h)[3] & 0xf) |
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#define DNS_HEADER_QDCOUNT(h) DNS__16BIT((h) + 4) |
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#define DNS_HEADER_ANCOUNT(h) DNS__16BIT((h) + 6) |
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#define DNS_HEADER_NSCOUNT(h) DNS__16BIT((h) + 8) |
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#define DNS_HEADER_ARCOUNT(h) DNS__16BIT((h) + 10) |
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/* Macros for constructing a DNS header */ |
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#define DNS_HEADER_SET_QID(h, v) DNS__SET16BIT(h, v) |
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#define DNS_HEADER_SET_QR(h, v) ((h)[2] |= (unsigned char)(((v) & 0x1) << 7)) |
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#define DNS_HEADER_SET_OPCODE(h, v) ((h)[2] |= (unsigned char)(((v) & 0xf) << 3)) |
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#define DNS_HEADER_SET_AA(h, v) ((h)[2] |= (unsigned char)(((v) & 0x1) << 2)) |
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#define DNS_HEADER_SET_TC(h, v) ((h)[2] |= (unsigned char)(((v) & 0x1) << 1)) |
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#define DNS_HEADER_SET_RD(h, v) ((h)[2] |= (unsigned char)((v) & 0x1)) |
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#define DNS_HEADER_SET_RA(h, v) ((h)[3] |= (unsigned char)(((v) & 0x1) << 7)) |
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#define DNS_HEADER_SET_Z(h, v) ((h)[3] |= (unsigned char)(((v) & 0x7) << 4)) |
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#define DNS_HEADER_SET_RCODE(h, v) ((h)[3] |= (unsigned char)((v) & 0xf)) |
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#define DNS_HEADER_SET_QDCOUNT(h, v) DNS__SET16BIT((h) + 4, v) |
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#define DNS_HEADER_SET_ANCOUNT(h, v) DNS__SET16BIT((h) + 6, v) |
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#define DNS_HEADER_SET_NSCOUNT(h, v) DNS__SET16BIT((h) + 8, v) |
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#define DNS_HEADER_SET_ARCOUNT(h, v) DNS__SET16BIT((h) + 10, v) |
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/* Macros for parsing the fixed part of a DNS question */ |
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#define DNS_QUESTION_TYPE(q) DNS__16BIT(q) |
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#define DNS_QUESTION_CLASS(q) DNS__16BIT((q) + 2) |
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/* Macros for constructing the fixed part of a DNS question */ |
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#define DNS_QUESTION_SET_TYPE(q, v) DNS__SET16BIT(q, v) |
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#define DNS_QUESTION_SET_CLASS(q, v) DNS__SET16BIT((q) + 2, v) |
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/* Macros for parsing the fixed part of a DNS resource record */ |
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#define DNS_RR_TYPE(r) DNS__16BIT(r) |
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#define DNS_RR_CLASS(r) DNS__16BIT((r) + 2) |
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#define DNS_RR_TTL(r) DNS__32BIT((r) + 4) |
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#define DNS_RR_LEN(r) DNS__16BIT((r) + 8) |
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/* Macros for constructing the fixed part of a DNS resource record */ |
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#define DNS_RR_SET_TYPE(r, v) DNS__SET16BIT(r, v) |
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#define DNS_RR_SET_CLASS(r, v) DNS__SET16BIT((r) + 2, v) |
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#define DNS_RR_SET_TTL(r, v) DNS__SET32BIT((r) + 4, v) |
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#define DNS_RR_SET_LEN(r, v) DNS__SET16BIT((r) + 8, v) |
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#endif /* HEADER_CARES_DNS_H */
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