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/*
* Copyright (c) 2015 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef included_dns_packet_h
#define included_dns_packet_h
/**
* DNS packet header format
*/
typedef CLIB_PACKED (struct {
u16 id; /**< transaction ID */
u16 flags; /**< flags */
u16 qdcount; /**< number of questions */
u16 anscount; /**< number of answers */
u16 nscount; /**< number of name servers */
u16 arcount; /**< number of additional records */
}) dns_header_t;
#define DNS_RCODE_MASK (0xf)
#define DNS_RCODE_NO_ERROR 0
#define DNS_RCODE_FORMAT_ERROR 1
#define DNS_RCODE_SERVER_FAILURE 2
#define DNS_RCODE_NAME_ERROR 3
#define DNS_RCODE_NOT_IMPLEMENTED 4
#define DNS_RCODE_REFUSED 5
#define DNS_RA (1<<7) /**< recursion available */
#define DNS_RD (1<<8) /**< recursion desired */
#define DNS_TC (1<<9) /**< truncation */
#define DNS_AA (1<<10) /**< authoritative answer */
#define DNS_OPCODE_MASK (0xf<<11) /**< opcode mask */
#define DNS_OPCODE_QUERY (0<<11) /**< standard query */
#define DNS_OPCODE_IQUERY (1<<11) /**< inverse query (deprecated) */
#define DNS_OPCODE_STATUS (2<<11) /**< server status */
#define DNS_QR (1<<15) /**< query=0, response=1 */
/*
* Note: in DNS-land, www.foobar.com is encoded as three "labels,"
* each of which amount to a 1 octet length followed by up to 63
* octets of name. Don't forget to add a "null root label" after the last
* real one, or the poor slob trying to parse the name will have
* no chance whatsoever.
*
* All RRs have the same top level format shown below:
*
* 1 1 1 1 1 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | |
* / /
* / NAME /
* | |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | TYPE |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | CLASS |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | TTL |
* | |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | RDLENGTH |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
* / RDATA /
* / /
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*
*
* DNS "questions" have the following format:
*
* 1 1 1 1 1 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | |
* / QNAME /
* / /
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | QTYPE |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | QCLASS |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*/
/**
* DNS "question" fixed header.
*/
typedef CLIB_PACKED (struct {
u16 type; /**< record type requested */
u16 class; /**< class, 1 = internet */
}) dns_query_t;
/**
* DNS RR fixed header.
*/
typedef CLIB_PACKED (struct {
u16 type; /**< record type */
u16 class; /**< class, 1 = internet */
u32 ttl; /**< time to live, in seconds */
u16 rdlength;
/**< length of r */
u8 rdata[0];
}) dns_rr_t;
/*
* There are quite a number of DNS record types
* Feel free to add as needed
*/
#define foreach_dns_type \
_(A, 1) /**< ip4 host address */ \
_(AAAA, 28) /**< ip6 host address */ \
_(ALL, 255) /**< all available data */ \
_(TEXT, 16) /**< a text string */ \
_(NAMESERVER, 2) /**< a nameserver */ \
_(CNAME, 5) /**< a CNAME (alias) */ \
_(MAIL_EXCHANGE, 15) /**< a mail exchange */ \
_(PTR, 12) /**< a PTR (pointer) record */ \
_(HINFO, 13) /**< Host info */
typedef enum
{
#define _(name,value) DNS_TYPE_##name = value,
foreach_dns_type
#undef _
} dns_type_t;
#define DNS_CLASS_IN 1 /**< The Internet */
#endif /* included_dns_packet_h */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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