msgencode.h revision 356345 
1/*
2 * util/data/msgencode.h - encode compressed DNS messages.
3 *
4 * Copyright (c) 2007, NLnet Labs. All rights reserved.
5 *
6 * This software is open source.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
14 *
15 * Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
18 *
19 * Neither the name of the NLNET LABS nor the names of its contributors may
20 * be used to endorse or promote products derived from this software without
21 * specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36/**
37 * \file
38 *
39 * This file contains temporary data structures and routines to create
40 * compressed DNS messages.
41 */
42
43#ifndef UTIL_DATA_MSGENCODE_H
44#define UTIL_DATA_MSGENCODE_H
45struct sldns_buffer;
46struct query_info;
47struct reply_info;
48struct regional;
49struct edns_data;
50
51/**
52 * Generate answer from reply_info.
53 * @param qinf: query information that provides query section in packet.
54 * @param rep: reply to fill in.
55 * @param id: id word from the query.
56 * @param qflags: flags word from the query.
57 * @param dest: buffer to put message into; will truncate if it does not fit.
58 * @param timenow: time to subtract.
59 * @param cached: set true if a cached reply (so no AA bit).
60 *	set false for the first reply.
61 * @param region: where to allocate temp variables (for compression).
62 * @param udpsize: size of the answer, 512, from EDNS, or 64k for TCP.
63 * @param edns: EDNS data included in the answer, NULL for none.
64 *	or if edns_present = 0, it is not included.
65 * @param dnssec: if 0 DNSSEC records are omitted from the answer.
66 * @param secure: if 1, the AD bit is set in the reply.
67 * @return: 0 on error (server failure).
68 */
69int reply_info_answer_encode(struct query_info* qinf, struct reply_info* rep,
70	uint16_t id, uint16_t qflags, struct sldns_buffer* dest, time_t timenow,
71	int cached, struct regional* region, uint16_t udpsize,
72	struct edns_data* edns, int dnssec, int secure);
73
74/**
75 * Regenerate the wireformat from the stored msg reply.
76 * If the buffer is too small then the message is truncated at a whole
77 * rrset and the TC bit set, or whole rrsets are left out of the additional
78 * and the TC bit is not set.
79 * @param qinfo: query info to store.
80 * @param rep: reply to store.
81 * @param id: id value to store, network order.
82 * @param flags: flags value to store, host order.
83 * @param buffer: buffer to store the packet into.
84 * @param timenow: time now, to adjust ttl values.
85 * @param region: to store temporary data in.
86 * @param udpsize: size of the answer, 512, from EDNS, or 64k for TCP.
87 * @param dnssec: if 0 DNSSEC records are omitted from the answer.
88 * @param minimise: if true, the answer is a minimal response, with
89 *   authority and additional removed if possible.
90 * @return: nonzero is success, or
91 *	0 on error: malloc failure (no log_err has been done).
92 */
93int reply_info_encode(struct query_info* qinfo, struct reply_info* rep,
94	uint16_t id, uint16_t flags, struct sldns_buffer* buffer, time_t timenow,
95	struct regional* region, uint16_t udpsize, int dnssec, int minimise);
96
97/**
98 * Encode query packet. Assumes the buffer is large enough.
99 * @param pkt: where to store the packet.
100 * @param qinfo: query info.
101 */
102void qinfo_query_encode(struct sldns_buffer* pkt, struct query_info* qinfo);
103
104/**
105 * Estimate size of EDNS record in packet. EDNS record will be no larger.
106 * @param edns: edns data or NULL.
107 * @return octets to reserve for EDNS.
108 */
109uint16_t calc_edns_field_size(struct edns_data* edns);
110
111/**
112 * Attach EDNS record to buffer. Buffer has complete packet. There must
113 * be enough room left for the EDNS record.
114 * @param pkt: packet added to.
115 * @param edns: if NULL or present=0, nothing is added to the packet.
116 */
117void attach_edns_record(struct sldns_buffer* pkt, struct edns_data* edns);
118
119/**
120 * Encode an error. With QR and RA set.
121 *
122 * @param pkt: where to store the packet.
123 * @param r: RCODE value to encode.
124 * @param qinfo: if not NULL, the query is included.
125 * @param qid: query ID to set in packet. network order.
126 * @param qflags: original query flags (to copy RD and CD bits). host order.
127 * @param edns: if not NULL, this is the query edns info,
128 * 	and an edns reply is attached. Only attached if EDNS record fits reply.
129 */
130void error_encode(struct sldns_buffer* pkt, int r, struct query_info* qinfo,
131	uint16_t qid, uint16_t qflags, struct edns_data* edns);
132
133#endif /* UTIL_DATA_MSGENCODE_H */
134