34af0ccf5c
Type: refactor Signed-off-by: Dave Barach <dave@barachs.net> Change-Id: I823c2cd307a4613653a2d20f564dda062d4da31b
157 lines
5.2 KiB
C
157 lines
5.2 KiB
C
/*
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* Copyright (c) 2015 Cisco and/or its affiliates.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef included_dns_packet_h
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#define included_dns_packet_h
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/**
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* DNS packet header format
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*/
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/* *INDENT-OFF* */
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typedef CLIB_PACKED (struct {
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u16 id; /**< transaction ID */
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u16 flags; /**< flags */
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u16 qdcount; /**< number of questions */
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u16 anscount; /**< number of answers */
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u16 nscount; /**< number of name servers */
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u16 arcount; /**< number of additional records */
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}) dns_header_t;
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/* *INDENT-ON* */
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#define DNS_RCODE_MASK (0xf)
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#define DNS_RCODE_NO_ERROR 0
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#define DNS_RCODE_FORMAT_ERROR 1
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#define DNS_RCODE_SERVER_FAILURE 2
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#define DNS_RCODE_NAME_ERROR 3
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#define DNS_RCODE_NOT_IMPLEMENTED 4
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#define DNS_RCODE_REFUSED 5
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#define DNS_RA (1<<7) /**< recursion available */
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#define DNS_RD (1<<8) /**< recursion desired */
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#define DNS_TC (1<<9) /**< truncation */
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#define DNS_AA (1<<10) /**< authoritative answer */
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#define DNS_OPCODE_MASK (0xf<<11) /**< opcode mask */
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#define DNS_OPCODE_QUERY (0<<11) /**< standard query */
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#define DNS_OPCODE_IQUERY (1<<11) /**< inverse query (deprecated) */
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#define DNS_OPCODE_STATUS (2<<11) /**< server status */
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#define DNS_QR (1<<15) /**< query=0, response=1 */
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/*
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* Note: in DNS-land, www.foobar.com is encoded as three "labels,"
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* each of which amount to a 1 octet length followed by up to 63
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* octets of name. Don't forget to add a "null root label" after the last
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* real one, or the poor slob trying to parse the name will have
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* no chance whatsoever.
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*
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* All RRs have the same top level format shown below:
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*
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* 1 1 1 1 1 1
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | |
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* / /
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* / NAME /
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* | |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | TYPE |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | CLASS |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | TTL |
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* | |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | RDLENGTH |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
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* / RDATA /
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* / /
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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*
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*
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* DNS "questions" have the following format:
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*
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* 1 1 1 1 1 1
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | |
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* / QNAME /
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* / /
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | QTYPE |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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* | QCLASS |
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* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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*/
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/**
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* DNS "question" fixed header.
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*/
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/* *INDENT-OFF* */
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typedef CLIB_PACKED (struct {
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u16 type; /**< record type requested */
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u16 class; /**< class, 1 = internet */
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}) dns_query_t;
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/* *INDENT-ON* */
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/**
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* DNS RR fixed header.
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*/
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/* *INDENT-OFF* */
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typedef CLIB_PACKED (struct {
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u16 type; /**< record type */
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u16 class; /**< class, 1 = internet */
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u32 ttl; /**< time to live, in seconds */
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u16 rdlength;
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/**< length of r */
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u8 rdata[0];
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}) dns_rr_t;
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/* *INDENT-ON* */
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/*
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* There are quite a number of DNS record types
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* Feel free to add as needed
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*/
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#define foreach_dns_type \
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_(A, 1) /**< ip4 host address */ \
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_(AAAA, 28) /**< ip6 host address */ \
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_(ALL, 255) /**< all available data */ \
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_(TEXT, 16) /**< a text string */ \
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_(NAMESERVER, 2) /**< a nameserver */ \
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_(CNAME, 5) /**< a CNAME (alias) */ \
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_(MAIL_EXCHANGE, 15) /**< a mail exchange */ \
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_(PTR, 12) /**< a PTR (pointer) record */ \
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_(HINFO, 13) /**< Host info */
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typedef enum
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{
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#define _(name,value) DNS_TYPE_##name = value,
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foreach_dns_type
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#undef _
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} dns_type_t;
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#define DNS_CLASS_IN 1 /**< The Internet */
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#endif /* included_dns_packet_h */
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/*
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* fd.io coding-style-patch-verification: ON
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*
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* Local Variables:
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* eval: (c-set-style "gnu")
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* End:
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*/
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