| /* MIT License |
| * |
| * Copyright (c) Massachusetts Institute of Technology |
| * Copyright (c) The c-ares project and its contributors |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| * SOFTWARE. |
| * |
| * SPDX-License-Identifier: MIT |
| */ |
| #ifndef HEADER_CARES_DNS_H |
| #define HEADER_CARES_DNS_H |
| |
| /* |
| * NOTE TO INTEGRATORS: |
| * |
| * This header is made public due to legacy projects relying on it. |
| * Please do not use the macros within this header, or include this |
| * header in your project as it may be removed in the future. |
| */ |
| |
| |
| /* |
| * Macro DNS__16BIT reads a network short (16 bit) given in network |
| * byte order, and returns its value as an unsigned short. |
| */ |
| #define DNS__16BIT(p) \ |
| ((unsigned short)((unsigned int)0xffff & \ |
| (((unsigned int)((unsigned char)(p)[0]) << 8U) | \ |
| ((unsigned int)((unsigned char)(p)[1]))))) |
| |
| /* |
| * Macro DNS__32BIT reads a network long (32 bit) given in network |
| * byte order, and returns its value as an unsigned int. |
| */ |
| #define DNS__32BIT(p) \ |
| ((unsigned int)(((unsigned int)((unsigned char)(p)[0]) << 24U) | \ |
| ((unsigned int)((unsigned char)(p)[1]) << 16U) | \ |
| ((unsigned int)((unsigned char)(p)[2]) << 8U) | \ |
| ((unsigned int)((unsigned char)(p)[3])))) |
| |
| #define DNS__SET16BIT(p, v) \ |
| (((p)[0] = (unsigned char)(((v) >> 8) & 0xff)), \ |
| ((p)[1] = (unsigned char)((v) & 0xff))) |
| #define DNS__SET32BIT(p, v) \ |
| (((p)[0] = (unsigned char)(((v) >> 24) & 0xff)), \ |
| ((p)[1] = (unsigned char)(((v) >> 16) & 0xff)), \ |
| ((p)[2] = (unsigned char)(((v) >> 8) & 0xff)), \ |
| ((p)[3] = (unsigned char)((v) & 0xff))) |
| |
| #if 0 |
| /* we cannot use this approach on systems where we can't access 16/32 bit |
| data on un-aligned addresses */ |
| # define DNS__16BIT(p) ntohs(*(unsigned short *)(p)) |
| # define DNS__32BIT(p) ntohl(*(unsigned long *)(p)) |
| # define DNS__SET16BIT(p, v) *(unsigned short *)(p) = htons(v) |
| # define DNS__SET32BIT(p, v) *(unsigned long *)(p) = htonl(v) |
| #endif |
| |
| /* Macros for parsing a DNS header */ |
| #define DNS_HEADER_QID(h) DNS__16BIT(h) |
| #define DNS_HEADER_QR(h) (((h)[2] >> 7) & 0x1) |
| #define DNS_HEADER_OPCODE(h) (((h)[2] >> 3) & 0xf) |
| #define DNS_HEADER_AA(h) (((h)[2] >> 2) & 0x1) |
| #define DNS_HEADER_TC(h) (((h)[2] >> 1) & 0x1) |
| #define DNS_HEADER_RD(h) ((h)[2] & 0x1) |
| #define DNS_HEADER_RA(h) (((h)[3] >> 7) & 0x1) |
| #define DNS_HEADER_Z(h) (((h)[3] >> 4) & 0x7) |
| #define DNS_HEADER_RCODE(h) ((h)[3] & 0xf) |
| #define DNS_HEADER_QDCOUNT(h) DNS__16BIT((h) + 4) |
| #define DNS_HEADER_ANCOUNT(h) DNS__16BIT((h) + 6) |
| #define DNS_HEADER_NSCOUNT(h) DNS__16BIT((h) + 8) |
| #define DNS_HEADER_ARCOUNT(h) DNS__16BIT((h) + 10) |
| |
| /* Macros for constructing a DNS header */ |
| #define DNS_HEADER_SET_QID(h, v) DNS__SET16BIT(h, v) |
| #define DNS_HEADER_SET_QR(h, v) ((h)[2] |= (unsigned char)(((v) & 0x1) << 7)) |
| #define DNS_HEADER_SET_OPCODE(h, v) \ |
| ((h)[2] |= (unsigned char)(((v) & 0xf) << 3)) |
| #define DNS_HEADER_SET_AA(h, v) ((h)[2] |= (unsigned char)(((v) & 0x1) << 2)) |
| #define DNS_HEADER_SET_TC(h, v) ((h)[2] |= (unsigned char)(((v) & 0x1) << 1)) |
| #define DNS_HEADER_SET_RD(h, v) ((h)[2] |= (unsigned char)((v) & 0x1)) |
| #define DNS_HEADER_SET_RA(h, v) ((h)[3] |= (unsigned char)(((v) & 0x1) << 7)) |
| #define DNS_HEADER_SET_Z(h, v) ((h)[3] |= (unsigned char)(((v) & 0x7) << 4)) |
| #define DNS_HEADER_SET_RCODE(h, v) ((h)[3] |= (unsigned char)((v) & 0xf)) |
| #define DNS_HEADER_SET_QDCOUNT(h, v) DNS__SET16BIT((h) + 4, v) |
| #define DNS_HEADER_SET_ANCOUNT(h, v) DNS__SET16BIT((h) + 6, v) |
| #define DNS_HEADER_SET_NSCOUNT(h, v) DNS__SET16BIT((h) + 8, v) |
| #define DNS_HEADER_SET_ARCOUNT(h, v) DNS__SET16BIT((h) + 10, v) |
| |
| /* Macros for parsing the fixed part of a DNS question */ |
| #define DNS_QUESTION_TYPE(q) DNS__16BIT(q) |
| #define DNS_QUESTION_CLASS(q) DNS__16BIT((q) + 2) |
| |
| /* Macros for constructing the fixed part of a DNS question */ |
| #define DNS_QUESTION_SET_TYPE(q, v) DNS__SET16BIT(q, v) |
| #define DNS_QUESTION_SET_CLASS(q, v) DNS__SET16BIT((q) + 2, v) |
| |
| /* Macros for parsing the fixed part of a DNS resource record */ |
| #define DNS_RR_TYPE(r) DNS__16BIT(r) |
| #define DNS_RR_CLASS(r) DNS__16BIT((r) + 2) |
| #define DNS_RR_TTL(r) DNS__32BIT((r) + 4) |
| #define DNS_RR_LEN(r) DNS__16BIT((r) + 8) |
| |
| /* Macros for constructing the fixed part of a DNS resource record */ |
| #define DNS_RR_SET_TYPE(r, v) DNS__SET16BIT(r, v) |
| #define DNS_RR_SET_CLASS(r, v) DNS__SET16BIT((r) + 2, v) |
| #define DNS_RR_SET_TTL(r, v) DNS__SET32BIT((r) + 4, v) |
| #define DNS_RR_SET_LEN(r, v) DNS__SET16BIT((r) + 8, v) |
| |
| #endif /* HEADER_CARES_DNS_H */ |
