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Diffstat (limited to 'ares/ares_dns.h')
| -rw-r--r-- | ares/ares_dns.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/ares/ares_dns.h b/ares/ares_dns.h new file mode 100644 index 000000000..cfab47352 --- /dev/null +++ b/ares/ares_dns.h @@ -0,0 +1,81 @@ +/* $Id$ */ + +/* Copyright 1998 by the Massachusetts Institute of Technology. + * + * Permission to use, copy, modify, and distribute this + * software and its documentation for any purpose and without + * fee is hereby granted, provided that the above copyright + * notice appear in all copies and that both that copyright + * notice and this permission notice appear in supporting + * documentation, and that the name of M.I.T. not be used in + * advertising or publicity pertaining to distribution of the + * software without specific, written prior permission. + * M.I.T. makes no representations about the suitability of + * this software for any purpose. It is provided "as is" + * without express or implied warranty. + */ + +#ifndef ARES__DNS_H +#define ARES__DNS_H + +#define DNS__16BIT(p) (((p)[0] << 8) | (p)[1]) +#define DNS__32BIT(p) (((p)[0] << 24) | ((p)[1] << 16) | \ + ((p)[2] << 8) | (p)[3]) +#define DNS__SET16BIT(p, v) (((p)[0] = ((v) >> 8) & 0xff), \ + ((p)[1] = (v) & 0xff)) +#define DNS__SET32BIT(p, v) (((p)[0] = ((v) >> 24) & 0xff), \ + ((p)[1] = ((v) >> 16) & 0xff), \ + ((p)[2] = ((v) >> 8) & 0xff), \ + ((p)[3] = (v) & 0xff)) + +/* 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] |= (((v) & 0x1) << 7)) +#define DNS_HEADER_SET_OPCODE(h, v) ((h)[2] |= (((v) & 0xf) << 3)) +#define DNS_HEADER_SET_AA(h, v) ((h)[2] |= (((v) & 0x1) << 2)) +#define DNS_HEADER_SET_TC(h, v) ((h)[2] |= (((v) & 0x1) << 1)) +#define DNS_HEADER_SET_RD(h, v) ((h)[2] |= (((v) & 0x1))) +#define DNS_HEADER_SET_RA(h, v) ((h)[3] |= (((v) & 0x1) << 7)) +#define DNS_HEADER_SET_Z(h, v) ((h)[3] |= (((v) & 0x7) << 4)) +#define DNS_HEADER_SET_RCODE(h, v) ((h)[3] |= (((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) DNS__SET16BIT(r, v) +#define DNS_RR_SET_CLASS(r) DNS__SET16BIT((r) + 2, v) +#define DNS_RR_SET_TTL(r) DNS__SET32BIT((r) + 4, v) +#define DNS_RR_SET_LEN(r) DNS__SET16BIT((r) + 8, v) + +#endif /* ARES__DNS_H */ |