unbound/util/data/msgencode.h

   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
  45 struct sldns_buffer;
  46 struct query_info;
  47 struct reply_info;
  48 struct regional;
  49 struct 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  */
  69 int 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  * @return: nonzero is success, or
  89  *      0 on error: malloc failure (no log_err has been done).
  90  */
  91 int reply_info_encode(struct query_info* qinfo, struct reply_info* rep,
  92         uint16_t id, uint16_t flags, struct sldns_buffer* buffer, time_t timenow,
  93         struct regional* region, uint16_t udpsize, int dnssec);
  94
  95 /**
  96  * Encode query packet. Assumes the buffer is large enough.
  97  * @param pkt: where to store the packet.
  98  * @param qinfo: query info.
  99  */
 100 void qinfo_query_encode(struct sldns_buffer* pkt, struct query_info* qinfo);
 101
 102 /**
 103  * Estimate size of EDNS record in packet. EDNS record will be no larger.
 104  * @param edns: edns data or NULL.
 105  * @return octets to reserve for EDNS.
 106  */
 107 uint16_t calc_edns_field_size(struct edns_data* edns);
 108
 109 /**
 110  * Attach EDNS record to buffer. Buffer has complete packet. There must
 111  * be enough room left for the EDNS record.
 112  * @param pkt: packet added to.
 113  * @param edns: if NULL or present=0, nothing is added to the packet.
 114  */
 115 void attach_edns_record(struct sldns_buffer* pkt, struct edns_data* edns);
 116
 117 /**
 118  * Encode an error. With QR and RA set.
 119  *
 120  * @param pkt: where to store the packet.
 121  * @param r: RCODE value to encode.
 122  * @param qinfo: if not NULL, the query is included.
 123  * @param qid: query ID to set in packet. network order.
 124  * @param qflags: original query flags (to copy RD and CD bits). host order.
 125  * @param edns: if not NULL, this is the query edns info,
 126  *      and an edns reply is attached. Only attached if EDNS record fits reply.
 127  */
 128 void error_encode(struct sldns_buffer* pkt, int r, struct query_info* qinfo,
 129         uint16_t qid, uint16_t qflags, struct edns_data* edns);
 130
 131 #endif /* UTIL_DATA_MSGENCODE_H */