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query.c
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query.c
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/*
* query.c -- nsd(8) the resolver.
*
* Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
*
* See LICENSE for the license.
*
*/
#include "config.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <netdb.h>
#include "answer.h"
#include "axfr.h"
#include "dns.h"
#include "dname.h"
#include "nsd.h"
#include "namedb.h"
#include "query.h"
#include "util.h"
#include "options.h"
#include "nsec3.h"
#include "tsig.h"
/* [Bug #253] Adding unnecessary NS RRset may lead to undesired truncation.
* This function determines if the final response packet needs the NS RRset
* included. Currently, it will only return negative if QTYPE == DNSKEY|DS.
* This way, resolvers won't fallback to TCP unnecessarily when priming
* trust anchors.
*/
static int answer_needs_ns(struct query *query);
static int add_rrset(struct query *query,
answer_type *answer,
rr_section_type section,
domain_type *owner,
rrset_type *rrset);
static void answer_authoritative(struct nsd *nsd,
struct query *q,
answer_type *answer,
size_t domain_number,
int exact,
domain_type *closest_match,
domain_type *closest_encloser,
const dname_type *qname);
static void answer_lookup_zone(struct nsd *nsd, struct query *q,
answer_type *answer, size_t domain_number,
int exact, domain_type *closest_match,
domain_type *closest_encloser,
const dname_type *qname);
void
query_put_dname_offset(struct query *q, domain_type *domain, uint16_t offset)
{
assert(q);
assert(domain);
assert(domain->number > 0);
if (offset > MAX_COMPRESSION_OFFSET)
return;
if (q->compressed_dname_count >= MAX_COMPRESSED_DNAMES)
return;
q->compressed_dname_offsets[domain->number] = offset;
q->compressed_dnames[q->compressed_dname_count] = domain;
++q->compressed_dname_count;
}
void
query_clear_dname_offsets(struct query *q, size_t max_offset)
{
while (q->compressed_dname_count > 0
&& (q->compressed_dname_offsets[q->compressed_dnames[q->compressed_dname_count - 1]->number]
>= max_offset))
{
q->compressed_dname_offsets[q->compressed_dnames[q->compressed_dname_count - 1]->number] = 0;
--q->compressed_dname_count;
}
}
void
query_clear_compression_tables(struct query *q)
{
uint16_t i;
for (i = 0; i < q->compressed_dname_count; ++i) {
assert(q->compressed_dnames);
q->compressed_dname_offsets[q->compressed_dnames[i]->number] = 0;
}
q->compressed_dname_count = 0;
}
void
query_add_compression_domain(struct query *q, domain_type *domain, uint16_t offset)
{
while (domain->parent) {
DEBUG(DEBUG_NAME_COMPRESSION, 2,
(LOG_INFO, "query dname: %s, number: %lu, offset: %u\n",
domain_to_string(domain),
(unsigned long) domain->number,
offset));
query_put_dname_offset(q, domain, offset);
offset += label_length(dname_name(domain_dname(domain))) + 1;
domain = domain->parent;
}
}
/*
* Generate an error response with the specified RCODE.
*/
query_state_type
query_error (struct query *q, nsd_rc_type rcode)
{
if (rcode == NSD_RC_DISCARD) {
return QUERY_DISCARDED;
}
buffer_clear(q->packet);
QR_SET(q->packet); /* This is an answer. */
AD_CLR(q->packet);
RCODE_SET(q->packet, (int) rcode); /* Error code. */
/* Truncate the question as well... */
QDCOUNT_SET(q->packet, 0);
ANCOUNT_SET(q->packet, 0);
NSCOUNT_SET(q->packet, 0);
ARCOUNT_SET(q->packet, 0);
buffer_set_position(q->packet, QHEADERSZ);
return QUERY_PROCESSED;
}
static int
query_ratelimit_err(nsd_type* nsd)
{
time_t now = time(NULL);
if(nsd->err_limit_time == now) {
/* see if limit is exceeded for this second */
if(nsd->err_limit_count++ > ERROR_RATELIMIT)
return 1;
} else {
/* new second, new limits */
nsd->err_limit_time = now;
nsd->err_limit_count = 1;
}
return 0;
}
static query_state_type
query_formerr (struct query *query, nsd_type* nsd)
{
int opcode = OPCODE(query->packet);
if(query_ratelimit_err(nsd))
return QUERY_DISCARDED;
FLAGS_SET(query->packet, FLAGS(query->packet) & 0x0100U);
/* Preserve the RD flag. Clear the rest. */
OPCODE_SET(query->packet, opcode);
return query_error(query, NSD_RC_FORMAT);
}
static void
query_cleanup(void *data)
{
query_type *query = (query_type *) data;
region_destroy(query->region);
}
query_type *
query_create(region_type *region, uint16_t *compressed_dname_offsets,
size_t compressed_dname_size, domain_type **compressed_dnames)
{
query_type *query
= (query_type *) region_alloc_zero(region, sizeof(query_type));
/* create region with large block size, because the initial chunk
saves many mallocs in the server */
query->region = region_create_custom(xalloc, free, 16384, 16384/8, 32, 0);
query->compressed_dname_offsets = compressed_dname_offsets;
query->compressed_dnames = compressed_dnames;
query->packet = buffer_create(region, QIOBUFSZ);
region_add_cleanup(region, query_cleanup, query);
query->compressed_dname_offsets_size = compressed_dname_size;
tsig_create_record(&query->tsig, region);
query->tsig_prepare_it = 1;
query->tsig_update_it = 1;
query->tsig_sign_it = 1;
return query;
}
void
query_reset(query_type *q, size_t maxlen, int is_tcp)
{
/*
* As long as less than 4Kb (region block size) has been used,
* this call to free_all is free, the block is saved for re-use,
* so no malloc() or free() calls are done.
* at present use of the region is for:
* o query qname dname_type (255 max).
* o wildcard expansion domain_type (7*ptr+u32+2bytes)+(5*ptr nsec3)
* o wildcard expansion for additional section domain_type.
* o nsec3 hashed name(s) (3 dnames for a nonexist_proof,
* one proof per wildcard and for nx domain).
*/
region_free_all(q->region);
q->remote_addrlen = (socklen_t)sizeof(q->remote_addr);
q->client_addrlen = (socklen_t)sizeof(q->client_addr);
q->is_proxied = 0;
q->maxlen = maxlen;
q->reserved_space = 0;
buffer_clear(q->packet);
edns_init_record(&q->edns);
tsig_init_record(&q->tsig, NULL, NULL);
q->tsig_prepare_it = 1;
q->tsig_update_it = 1;
q->tsig_sign_it = 1;
q->tcp = is_tcp;
q->qname = NULL;
q->qtype = 0;
q->qclass = 0;
q->zone = NULL;
q->opcode = 0;
q->cname_count = 0;
q->delegation_domain = NULL;
q->delegation_rrset = NULL;
q->compressed_dname_count = 0;
q->number_temporary_domains = 0;
q->axfr_is_done = 0;
q->axfr_zone = NULL;
q->axfr_current_domain = NULL;
q->axfr_current_rrset = NULL;
q->axfr_current_rr = 0;
q->ixfr_is_done = 0;
q->ixfr_data = NULL;
q->ixfr_count_newsoa = 0;
q->ixfr_count_oldsoa = 0;
q->ixfr_count_del = 0;
q->ixfr_count_add = 0;
#ifdef RATELIMIT
q->wildcard_domain = NULL;
#endif
}
/* get a temporary domain number (or 0=failure) */
static domain_type*
query_get_tempdomain(struct query *q)
{
static domain_type d[EXTRA_DOMAIN_NUMBERS];
if(q->number_temporary_domains >= EXTRA_DOMAIN_NUMBERS)
return 0;
q->number_temporary_domains ++;
memset(&d[q->number_temporary_domains-1], 0, sizeof(domain_type));
d[q->number_temporary_domains-1].number = q->compressed_dname_offsets_size +
q->number_temporary_domains - 1;
return &d[q->number_temporary_domains-1];
}
static void
query_addtxt(struct query *q,
const uint8_t *dname,
uint16_t klass,
uint32_t ttl,
const char *txt)
{
size_t txt_length = strlen(txt);
uint8_t len = (uint8_t) txt_length;
assert(txt_length <= UCHAR_MAX);
/* Add the dname */
if (dname >= buffer_begin(q->packet)
&& dname <= buffer_current(q->packet))
{
buffer_write_u16(q->packet,
0xc000 | (dname - buffer_begin(q->packet)));
} else {
buffer_write(q->packet, dname + 1, *dname);
}
buffer_write_u16(q->packet, TYPE_TXT);
buffer_write_u16(q->packet, klass);
buffer_write_u32(q->packet, ttl);
buffer_write_u16(q->packet, len + 1);
buffer_write_u8(q->packet, len);
buffer_write(q->packet, txt, len);
}
/*
* Parse the question section of a query. The normalized query name
* is stored in QUERY->name, the class in QUERY->klass, and the type
* in QUERY->type.
*/
static int
process_query_section(query_type *query)
{
uint8_t qnamebuf[MAXDOMAINLEN];
buffer_set_position(query->packet, QHEADERSZ);
/* Lets parse the query name and convert it to lower case. */
if(!packet_read_query_section(query->packet, qnamebuf,
&query->qtype, &query->qclass))
return 0;
query->qname = dname_make(query->region, qnamebuf, 1);
return 1;
}
/*
* Process an optional EDNS OPT record. Sets QUERY->EDNS to 0 if
* there was no EDNS record, to -1 if there was an invalid or
* unsupported EDNS record, and to 1 otherwise. Updates QUERY->MAXLEN
* if the EDNS record specifies a maximum supported response length.
*
* Return NSD_RC_FORMAT on failure, NSD_RC_OK on success.
*/
static nsd_rc_type
process_edns(nsd_type* nsd, struct query *q)
{
if (q->edns.status == EDNS_ERROR) {
/* The only error is VERSION not implemented */
return NSD_RC_FORMAT;
}
if (q->edns.status == EDNS_OK) {
/* Only care about UDP size larger than normal... */
if (!q->tcp && q->edns.maxlen > UDP_MAX_MESSAGE_LEN) {
size_t edns_size;
#if defined(INET6)
if (q->client_addr.ss_family == AF_INET6) {
edns_size = nsd->ipv6_edns_size;
} else
#endif
edns_size = nsd->ipv4_edns_size;
if (q->edns.maxlen < edns_size) {
q->maxlen = q->edns.maxlen;
} else {
q->maxlen = edns_size;
}
#if defined(INET6) && !defined(IPV6_USE_MIN_MTU) && !defined(IPV6_MTU)
/*
* Use IPv6 minimum MTU to avoid sending
* packets that are too large for some links.
* IPv6 will not automatically fragment in
* this case (unlike IPv4).
*/
if (q->client_addr.ss_family == AF_INET6
&& q->maxlen > IPV6_MIN_MTU)
{
q->maxlen = IPV6_MIN_MTU;
}
#endif
}
/* Strip the OPT resource record off... */
buffer_set_position(q->packet, q->edns.position);
buffer_set_limit(q->packet, q->edns.position);
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1);
}
return NSD_RC_OK;
}
/*
* Processes TSIG.
* Sets error when tsig does not verify on the query.
*/
static nsd_rc_type
process_tsig(struct query* q)
{
if(q->tsig.status == TSIG_ERROR)
return NSD_RC_FORMAT;
if(q->tsig.status == TSIG_OK) {
if(!tsig_from_query(&q->tsig)) {
char a[128];
addr2str(&q->client_addr, a, sizeof(a));
log_msg(LOG_ERR, "query: bad tsig (%s) for key %s from %s",
tsig_error(q->tsig.error_code),
dname_to_string(q->tsig.key_name, NULL), a);
return NSD_RC_NOTAUTH;
}
buffer_set_limit(q->packet, q->tsig.position);
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) - 1);
tsig_prepare(&q->tsig);
tsig_update(&q->tsig, q->packet, buffer_limit(q->packet));
if(!tsig_verify(&q->tsig)) {
char a[128];
addr2str(&q->client_addr, a, sizeof(a));
log_msg(LOG_ERR, "query: bad tsig signature for key %s from %s",
dname_to_string(q->tsig.key->name, NULL), a);
return NSD_RC_NOTAUTH;
}
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "query good tsig signature for %s",
dname_to_string(q->tsig.key->name, NULL)));
}
return NSD_RC_OK;
}
/*
* Check notify acl and forward to xfrd (or return an error).
*/
static query_state_type
answer_notify(struct nsd* nsd, struct query *query)
{
int acl_num, acl_num_xfr;
struct acl_options *why;
nsd_rc_type rc;
struct zone_options* zone_opt;
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s processing acl",
dname_to_string(query->qname, NULL)));
zone_opt = zone_options_find(nsd->options, query->qname);
if(!zone_opt)
return query_error(query, NSD_RC_NXDOMAIN);
if(!nsd->this_child) /* we are in debug mode or something */
return query_error(query, NSD_RC_SERVFAIL);
if(!tsig_find_rr(&query->tsig, query->packet)) {
DEBUG(DEBUG_XFRD,2, (LOG_ERR, "bad tsig RR format"));
return query_error(query, NSD_RC_FORMAT);
}
rc = process_tsig(query);
if(rc != NSD_RC_OK)
return query_error(query, rc);
/* check if it passes acl */
if(query->is_proxied && acl_check_incoming_block_proxy(
zone_opt->pattern->allow_notify, query, &why) == -1) {
/* the proxy address is blocked */
if (verbosity >= 2) {
char address[128], proxy[128];
addr2str(&query->client_addr, address, sizeof(address));
addr2str(&query->remote_addr, proxy, sizeof(proxy));
VERBOSITY(2, (LOG_INFO, "notify for %s from %s via proxy %s refused because of proxy, %s%s%s",
dname_to_string(query->qname, NULL),
address, proxy,
(why?why->ip_address_spec:""),
(why&&why->ip_address_spec[0]?" ":""),
(why ? ( why->nokey ? "NOKEY"
: why->blocked ? "BLOCKED"
: why->key_name )
: "no acl matches")));
}
return query_error(query, NSD_RC_REFUSE);
}
if((acl_num = acl_check_incoming(zone_opt->pattern->allow_notify, query,
&why)) != -1)
{
sig_atomic_t mode = NSD_PASS_TO_XFRD;
int s = nsd->this_child->parent_fd;
uint16_t sz;
uint32_t acl_send = htonl(acl_num);
uint32_t acl_xfr;
size_t pos;
/* Find priority candidate for request XFR. -1 if no match */
acl_num_xfr = acl_check_incoming(
zone_opt->pattern->request_xfr, query, NULL);
acl_xfr = htonl(acl_num_xfr);
assert(why);
DEBUG(DEBUG_XFRD,1, (LOG_INFO, "got notify %s passed acl %s %s",
dname_to_string(query->qname, NULL),
why->ip_address_spec,
why->nokey?"NOKEY":
(why->blocked?"BLOCKED":why->key_name)));
sz = buffer_limit(query->packet);
if(buffer_limit(query->packet) > MAX_PACKET_SIZE)
return query_error(query, NSD_RC_SERVFAIL);
/* forward to xfrd for processing
Note. Blocking IPC I/O, but acl is OK. */
sz = htons(sz);
if(!write_socket(s, &mode, sizeof(mode)) ||
!write_socket(s, &sz, sizeof(sz)) ||
!write_socket(s, buffer_begin(query->packet),
buffer_limit(query->packet)) ||
!write_socket(s, &acl_send, sizeof(acl_send)) ||
!write_socket(s, &acl_xfr, sizeof(acl_xfr))) {
log_msg(LOG_ERR, "error in IPC notify server2main, %s",
strerror(errno));
return query_error(query, NSD_RC_SERVFAIL);
}
if(verbosity >= 1) {
uint32_t serial = 0;
char address[128];
addr2str(&query->client_addr, address, sizeof(address));
if(packet_find_notify_serial(query->packet, &serial))
VERBOSITY(1, (LOG_INFO, "notify for %s from %s serial %u",
dname_to_string(query->qname, NULL), address,
(unsigned)serial));
else
VERBOSITY(1, (LOG_INFO, "notify for %s from %s",
dname_to_string(query->qname, NULL), address));
}
/* create notify reply - keep same query contents */
QR_SET(query->packet); /* This is an answer. */
AA_SET(query->packet); /* we are authoritative. */
ANCOUNT_SET(query->packet, 0);
NSCOUNT_SET(query->packet, 0);
ARCOUNT_SET(query->packet, 0);
RCODE_SET(query->packet, RCODE_OK); /* Error code. */
/* position is right after the query */
pos = buffer_position(query->packet);
buffer_clear(query->packet);
buffer_set_position(query->packet, pos);
/* tsig is added in add_additional later (if needed) */
return QUERY_PROCESSED;
}
if (verbosity >= 2) {
char address[128];
addr2str(&query->client_addr, address, sizeof(address));
VERBOSITY(2, (LOG_INFO, "notify for %s from %s refused, %s%s%s",
dname_to_string(query->qname, NULL),
address,
(why?why->ip_address_spec:""),
(why&&why->ip_address_spec[0]?" ":""),
(why ? ( why->nokey ? "NOKEY"
: why->blocked ? "BLOCKED"
: why->key_name )
: "no acl matches")));
}
return query_error(query, NSD_RC_REFUSE);
}
/*
* Answer a query in the CHAOS class.
*/
static query_state_type
answer_chaos(struct nsd *nsd, query_type *q)
{
AA_CLR(q->packet);
switch (q->qtype) {
case TYPE_ANY:
case TYPE_TXT:
if ((q->qname->name_size == 11
&& memcmp(dname_name(q->qname), "\002id\006server", 11) == 0) ||
(q->qname->name_size == 15
&& memcmp(dname_name(q->qname), "\010hostname\004bind", 15) == 0))
{
if(!nsd->options->hide_identity) {
/* Add ID */
query_addtxt(q,
buffer_begin(q->packet) + QHEADERSZ,
CLASS_CH,
0,
nsd->identity);
ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1);
} else {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.19. Extended DNS Error Code 18 - Prohibited */
q->edns.ede = EDE_PROHIBITED;
}
} else if ((q->qname->name_size == 16
&& memcmp(dname_name(q->qname), "\007version\006server", 16) == 0) ||
(q->qname->name_size == 14
&& memcmp(dname_name(q->qname), "\007version\004bind", 14) == 0))
{
if(!nsd->options->hide_version) {
/* Add version */
query_addtxt(q,
buffer_begin(q->packet) + QHEADERSZ,
CLASS_CH,
0,
nsd->version);
ANCOUNT_SET(q->packet, ANCOUNT(q->packet) + 1);
} else {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.19. Extended DNS Error Code 18 - Prohibited */
q->edns.ede = EDE_PROHIBITED;
}
} else {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.22. Extended DNS Error Code 21 - Not Supported */
q->edns.ede = EDE_NOT_SUPPORTED;
}
break;
default:
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.22. Extended DNS Error Code 21 - Not Supported */
q->edns.ede = EDE_NOT_SUPPORTED;
break;
}
return QUERY_PROCESSED;
}
/*
* Find the covering NSEC for a non-existent domain name. Normally
* the NSEC will be located at CLOSEST_MATCH, except when it is an
* empty non-terminal. In this case the NSEC may be located at the
* previous domain name (in canonical ordering).
*/
static domain_type *
find_covering_nsec(domain_type *closest_match,
zone_type *zone,
rrset_type **nsec_rrset)
{
assert(closest_match);
assert(nsec_rrset);
/* loop away temporary created domains. For real ones it is &RBTREE_NULL */
#ifdef USE_RADIX_TREE
while (closest_match->rnode == NULL)
#else
while (closest_match->node.parent == NULL)
#endif
closest_match = closest_match->parent;
while (closest_match) {
*nsec_rrset = domain_find_rrset(closest_match, zone, TYPE_NSEC);
if (*nsec_rrset) {
return closest_match;
}
if (closest_match == zone->apex) {
/* Don't look outside the current zone. */
return NULL;
}
closest_match = domain_previous(closest_match);
}
return NULL;
}
struct additional_rr_types
{
uint16_t rr_type;
rr_section_type rr_section;
};
struct additional_rr_types default_additional_rr_types[] = {
{ TYPE_A, ADDITIONAL_A_SECTION },
{ TYPE_AAAA, ADDITIONAL_AAAA_SECTION },
{ 0, (rr_section_type) 0 }
};
struct additional_rr_types swap_aaaa_additional_rr_types[] = {
{ TYPE_AAAA, ADDITIONAL_A_SECTION },
{ TYPE_A, ADDITIONAL_AAAA_SECTION },
{ 0, (rr_section_type) 0 }
};
struct additional_rr_types rt_additional_rr_types[] = {
{ TYPE_A, ADDITIONAL_A_SECTION },
{ TYPE_AAAA, ADDITIONAL_AAAA_SECTION },
{ TYPE_X25, ADDITIONAL_OTHER_SECTION },
{ TYPE_ISDN, ADDITIONAL_OTHER_SECTION },
{ 0, (rr_section_type) 0 }
};
static void
add_additional_rrsets(struct query *query, answer_type *answer,
rrset_type *master_rrset, size_t rdata_index,
int allow_glue, struct additional_rr_types types[])
{
size_t i;
assert(query);
assert(answer);
assert(master_rrset);
assert(rdata_atom_is_domain(rrset_rrtype(master_rrset), rdata_index));
for (i = 0; i < master_rrset->rr_count; ++i) {
int j;
domain_type *additional = rdata_atom_domain(master_rrset->rrs[i].rdatas[rdata_index]);
domain_type *match = additional;
assert(additional);
if (!allow_glue && domain_is_glue(match, query->zone))
continue;
/*
* Check to see if we need to generate the dependent
* based on a wildcard domain.
*/
while (!match->is_existing) {
match = match->parent;
}
if (additional != match && domain_wildcard_child(match)) {
domain_type *wildcard_child = domain_wildcard_child(match);
domain_type *temp = (domain_type *) region_alloc(
query->region, sizeof(domain_type));
#ifdef USE_RADIX_TREE
temp->rnode = NULL;
temp->dname = additional->dname;
#else
memcpy(&temp->node, &additional->node, sizeof(rbnode_type));
temp->node.parent = NULL;
#endif
temp->number = additional->number;
temp->parent = match;
temp->wildcard_child_closest_match = temp;
temp->rrsets = wildcard_child->rrsets;
temp->is_existing = wildcard_child->is_existing;
additional = temp;
}
for (j = 0; types[j].rr_type != 0; ++j) {
rrset_type *rrset = domain_find_rrset(
additional, query->zone, types[j].rr_type);
if (rrset) {
answer_add_rrset(answer, types[j].rr_section,
additional, rrset);
}
}
}
}
static int
answer_needs_ns(struct query* query)
{
assert(query);
/* Currently, only troublesome for DNSKEY and DS,
* cuz their RRSETs are quite large. */
return (query->qtype != TYPE_DNSKEY && query->qtype != TYPE_DS
&& query->qtype != TYPE_ANY);
}
static int
add_rrset(struct query *query,
answer_type *answer,
rr_section_type section,
domain_type *owner,
rrset_type *rrset)
{
int result;
assert(query);
assert(answer);
assert(owner);
assert(rrset);
assert(rrset_rrclass(rrset) == CLASS_IN);
result = answer_add_rrset(answer, section, owner, rrset);
if(minimal_responses && section != AUTHORITY_SECTION &&
query->qtype != TYPE_NS)
return result;
switch (rrset_rrtype(rrset)) {
case TYPE_NS:
#if defined(INET6)
/* if query over IPv6, swap A and AAAA; put AAAA first */
add_additional_rrsets(query, answer, rrset, 0, 1,
(query->client_addr.ss_family == AF_INET6)?
swap_aaaa_additional_rr_types:
default_additional_rr_types);
#else
add_additional_rrsets(query, answer, rrset, 0, 1,
default_additional_rr_types);
#endif
break;
case TYPE_MB:
add_additional_rrsets(query, answer, rrset, 0, 0,
default_additional_rr_types);
break;
case TYPE_MX:
case TYPE_KX:
add_additional_rrsets(query, answer, rrset, 1, 0,
default_additional_rr_types);
break;
case TYPE_RT:
add_additional_rrsets(query, answer, rrset, 1, 0,
rt_additional_rr_types);
break;
case TYPE_SRV:
add_additional_rrsets(query, answer, rrset, 3, 0,
default_additional_rr_types);
break;
default:
break;
}
return result;
}
/* returns 0 on error, or the domain number for to_name.
from_name is changes to to_name by the DNAME rr.
DNAME rr is from src to dest.
closest encloser encloses the to_name. */
static size_t
query_synthesize_cname(struct query* q, struct answer* answer, const dname_type* from_name,
const dname_type* to_name, domain_type* src, domain_type* to_closest_encloser,
domain_type** to_closest_match, uint32_t ttl)
{
/* add temporary domains for from_name and to_name and all
their (not allocated yet) parents */
/* any domains below src are not_existing (because of DNAME at src) */
int i;
size_t j;
domain_type* cname_domain;
domain_type* cname_dest;
rrset_type* rrset;
domain_type* lastparent = src;
assert(q && answer && from_name && to_name && src && to_closest_encloser);
assert(to_closest_match);
/* check for loop by duplicate CNAME rrset synthesized */
for(j=0; j<answer->rrset_count; ++j) {
if(answer->section[j] == ANSWER_SECTION &&
answer->rrsets[j]->rr_count == 1 &&
answer->rrsets[j]->rrs[0].type == TYPE_CNAME &&
dname_compare(domain_dname(answer->rrsets[j]->rrs[0].owner), from_name) == 0 &&
answer->rrsets[j]->rrs[0].rdata_count == 1 &&
dname_compare(domain_dname(answer->rrsets[j]->rrs[0].rdatas->domain), to_name) == 0) {
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "loop for synthesized CNAME rrset for query %s", dname_to_string(q->qname, NULL)));
return 0;
}
}
/* allocate source part */
for(i=0; i < from_name->label_count - domain_dname(src)->label_count; i++)
{
domain_type* newdom = query_get_tempdomain(q);
if(!newdom)
return 0;
newdom->is_existing = 1;
newdom->parent = lastparent;
#ifdef USE_RADIX_TREE
newdom->dname
#else
newdom->node.key
#endif
= dname_partial_copy(q->region,
from_name, domain_dname(src)->label_count + i + 1);
if(dname_compare(domain_dname(newdom), q->qname) == 0) {
/* 0 good for query name, otherwise new number */
newdom->number = 0;
}
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain src %d. %s nr %d", i,
domain_to_string(newdom), (int)newdom->number));
lastparent = newdom;
}
cname_domain = lastparent;
/* allocate dest part */
lastparent = to_closest_encloser;
for(i=0; i < to_name->label_count - domain_dname(to_closest_encloser)->label_count;
i++)
{
domain_type* newdom = query_get_tempdomain(q);
if(!newdom)
return 0;
newdom->is_existing = 0;
newdom->parent = lastparent;
#ifdef USE_RADIX_TREE
newdom->dname
#else
newdom->node.key
#endif
= dname_partial_copy(q->region,
to_name, domain_dname(to_closest_encloser)->label_count + i + 1);
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "created temp domain dest %d. %s nr %d", i,
domain_to_string(newdom), (int)newdom->number));
lastparent = newdom;
}
cname_dest = lastparent;
*to_closest_match = cname_dest;
/* allocate the CNAME RR */
rrset = (rrset_type*) region_alloc(q->region, sizeof(rrset_type));
memset(rrset, 0, sizeof(rrset_type));
rrset->zone = q->zone;
rrset->rr_count = 1;
rrset->rrs = (rr_type*) region_alloc(q->region, sizeof(rr_type));
memset(rrset->rrs, 0, sizeof(rr_type));
rrset->rrs->owner = cname_domain;
rrset->rrs->ttl = ttl;
rrset->rrs->type = TYPE_CNAME;
rrset->rrs->klass = CLASS_IN;
rrset->rrs->rdata_count = 1;
rrset->rrs->rdatas = (rdata_atom_type*)region_alloc(q->region,
sizeof(rdata_atom_type));
rrset->rrs->rdatas->domain = cname_dest;
if(!add_rrset(q, answer, ANSWER_SECTION, cname_domain, rrset)) {
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "could not add synthesized CNAME rrset to packet for query %s", dname_to_string(q->qname, NULL)));
/* failure to add CNAME; likely is a loop, the same twice */
return 0;
}
return cname_dest->number;
}
/*
* Answer delegation information.
*
* DNSSEC: Include the DS RRset if present. Otherwise include an NSEC
* record proving the DS RRset does not exist.
*/
static void
answer_delegation(query_type *query, answer_type *answer)
{
assert(answer);
assert(query->delegation_domain);
assert(query->delegation_rrset);
if (query->cname_count == 0) {
AA_CLR(query->packet);
} else {
AA_SET(query->packet);
}
add_rrset(query,
answer,
AUTHORITY_SECTION,
query->delegation_domain,
query->delegation_rrset);
if (query->edns.dnssec_ok && zone_is_secure(query->zone)) {
rrset_type *rrset;
if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_DS))) {
add_rrset(query, answer, AUTHORITY_SECTION,
query->delegation_domain, rrset);
#ifdef NSEC3
} else if (query->zone->nsec3_param) {
nsec3_answer_delegation(query, answer);
#endif
} else if ((rrset = domain_find_rrset(query->delegation_domain, query->zone, TYPE_NSEC))) {
add_rrset(query, answer, AUTHORITY_SECTION,
query->delegation_domain, rrset);
}
}
}
/*
* Answer SOA information.
*/
static void
answer_soa(struct query *query, answer_type *answer)
{
if (query->qclass != CLASS_ANY) {
add_rrset(query, answer,
AUTHORITY_SECTION,
query->zone->apex,
query->zone->soa_nx_rrset);
}
}
/*
* Answer that the domain name exists but there is no RRset with the
* requested type.
*
* DNSSEC: Include the correct NSEC record proving that the type does
* not exist. In the wildcard no data (3.1.3.4) case the wildcard IS
* NOT expanded, so the ORIGINAL parameter must point to the original
* wildcard entry, not to the generated entry.
*/
static void
answer_nodata(struct query *query, answer_type *answer, domain_type *original)
{
answer_soa(query, answer);
#ifdef NSEC3
if (query->edns.dnssec_ok && query->zone->nsec3_param) {
nsec3_answer_nodata(query, answer, original);
} else
#endif
if (query->edns.dnssec_ok && zone_is_secure(query->zone)) {
domain_type *nsec_domain;
rrset_type *nsec_rrset;
nsec_domain = find_covering_nsec(original, query->zone, &nsec_rrset);
if (nsec_domain) {
add_rrset(query, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset);
}
}
}