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      1 /*
      2  * answer.c -- manipulating query answers and encoding them.
      3  *
      4  * Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
      5  *
      6  * See LICENSE for the license.
      7  *
      8  */
      9 
     10 #include "config.h"
     11 
     12 #include <string.h>
     13 
     14 #include "answer.h"
     15 #include "packet.h"
     16 #include "query.h"
     17 
     18 void
     19 answer_init(answer_type *answer)
     20 {
     21 	answer->rrset_count = 0;
     22 }
     23 
     24 int
     25 answer_add_rrset(answer_type *answer, rr_section_type section,
     26 		 domain_type *domain, rrset_type *rrset)
     27 {
     28 	size_t i;
     29 
     30 	assert(section >= ANSWER_SECTION && section < RR_SECTION_COUNT);
     31 	assert(domain);
     32 	assert(rrset);
     33 
     34 	/* Don't add an RRset multiple times.  */
     35 	for (i = 0; i < answer->rrset_count; ++i) {
     36 		if (answer->rrsets[i] == rrset &&
     37 			answer->domains[i]->number == domain->number) {
     38 			if (section < answer->section[i]) {
     39 				answer->section[i] = section;
     40 				return 1;
     41 			} else {
     42 				return 0;
     43 			}
     44 		}
     45 	}
     46 
     47 	if (answer->rrset_count >= MAXRRSPP) {
     48 		/* XXX: Generate warning/error? */
     49 		return 0;
     50 	}
     51 
     52 	answer->section[answer->rrset_count] = section;
     53 	answer->domains[answer->rrset_count] = domain;
     54 	answer->rrsets[answer->rrset_count] = rrset;
     55 	++answer->rrset_count;
     56 
     57 	return 1;
     58 }
     59 
     60 void
     61 encode_answer(query_type *q, const answer_type *answer)
     62 {
     63 	uint16_t counts[RR_SECTION_COUNT];
     64 	rr_section_type section;
     65 	size_t i;
     66 	int minimal_respsize = IPV4_MINIMAL_RESPONSE_SIZE;
     67 	int done = 0;
     68 
     69 #if defined(INET6) && defined(MINIMAL_RESPONSES)
     70 	if (q->client_addr.ss_family == AF_INET6)
     71 		minimal_respsize = IPV6_MINIMAL_RESPONSE_SIZE;
     72 #endif
     73 
     74 	for (section = ANSWER_SECTION; section < RR_SECTION_COUNT; ++section) {
     75 		counts[section] = 0;
     76 	}
     77 
     78 	for (section = ANSWER_SECTION;
     79 	     !TC(q->packet) && section < RR_SECTION_COUNT;
     80 	     ++section) {
     81 
     82 		for (i = 0; !TC(q->packet) && i < answer->rrset_count; ++i) {
     83 			if (answer->section[i] == section) {
     84 				counts[section] += packet_encode_rrset(
     85 					q,
     86 					answer->domains[i],
     87 					answer->rrsets[i],
     88 					section, minimal_respsize, &done);
     89 			}
     90 		}
     91 #ifdef MINIMAL_RESPONSES
     92 		/**
     93 		 * done is set prematurely, because the minimal response size
     94 		 * has been reached. No need to try adding RRsets in following
     95 		 * sections.
     96 		 */
     97 		if (done) {
     98 			/* delegations should have a usable address in it */
     99 			if(section == ADDITIONAL_A_SECTION &&
    100 				counts[ADDITIONAL_A_SECTION] == 0 &&
    101 				q->delegation_domain)
    102 				TC_SET(q->packet);
    103 			break;
    104 		}
    105 #endif
    106 	}
    107 
    108 	ANCOUNT_SET(q->packet, counts[ANSWER_SECTION]);
    109 	NSCOUNT_SET(q->packet,
    110 		    counts[AUTHORITY_SECTION]
    111 		    + counts[OPTIONAL_AUTHORITY_SECTION]);
    112 	ARCOUNT_SET(q->packet,
    113 		    counts[ADDITIONAL_A_SECTION]
    114 		    + counts[ADDITIONAL_AAAA_SECTION]
    115 		    + counts[ADDITIONAL_OTHER_SECTION]);
    116 }
    117