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src/usr.sbin/nsd/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",
dname_to_string(query->qname, NULL),
address, proxy,
(why?why->ip_address_spec:"."),
(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",
dname_to_string(query->qname, NULL),
address,
(why?why->ip_address_spec:"."),
(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);
}
}
}
static void
answer_nxdomain(query_type *query, answer_type *answer)
{
RCODE_SET(query->packet, RCODE_NXDOMAIN);
answer_soa(query, answer);
}
/*
* Answer domain information (or SOA if we do not have an RRset for
* the type specified by the query).
*/
static void
answer_domain(struct nsd* nsd, struct query *q, answer_type *answer,
domain_type *domain, domain_type *original)
{
rrset_type *rrset;
if (q->qtype == TYPE_ANY) {
rrset_type *preferred_rrset = NULL;
rrset_type *normal_rrset = NULL;
rrset_type *non_preferred_rrset = NULL;
/*
* Minimize response size for ANY, with one RRset
* according to RFC 8482(4.1).
* Prefers popular and not large rtypes (A,AAAA,...)
* lowering large ones (DNSKEY,RRSIG,...).
*/
for (rrset = domain_find_any_rrset(domain, q->zone); rrset; rrset = rrset->next) {
if (rrset->zone == q->zone
#ifdef NSEC3
&& rrset_rrtype(rrset) != TYPE_NSEC3
#endif
/*
* Don't include the RRSIG RRset when
* DNSSEC is used, because it is added
* automatically on an per-RRset basis.
*/
&& !(q->edns.dnssec_ok
&& zone_is_secure(q->zone)
&& rrset_rrtype(rrset) == TYPE_RRSIG))
{
switch(rrset_rrtype(rrset)) {
case TYPE_A:
case TYPE_AAAA:
case TYPE_SOA:
case TYPE_MX:
case TYPE_PTR:
preferred_rrset = rrset;
break;
case TYPE_DNSKEY:
case TYPE_RRSIG:
case TYPE_NSEC:
non_preferred_rrset = rrset;
break;
default:
normal_rrset = rrset;
}
if (preferred_rrset) break;
}
}
if (preferred_rrset) {
add_rrset(q, answer, ANSWER_SECTION, domain, preferred_rrset);
} else if (normal_rrset) {
add_rrset(q, answer, ANSWER_SECTION, domain, normal_rrset);
} else if (non_preferred_rrset) {
add_rrset(q, answer, ANSWER_SECTION, domain, non_preferred_rrset);
} else {
answer_nodata(q, answer, original);
return;
}
#ifdef NSEC3
} else if (q->qtype == TYPE_NSEC3) {
answer_nodata(q, answer, original);
return;
#endif
} else if ((rrset = domain_find_rrset(domain, q->zone, q->qtype))) {
add_rrset(q, answer, ANSWER_SECTION, domain, rrset);
} else if ((rrset = domain_find_rrset(domain, q->zone, TYPE_CNAME))) {
int added;
/*
* If the CNAME is not added it is already in the
* answer, so we have a CNAME loop. Don't follow the
* CNAME target in this case.
*/
added = add_rrset(q, answer, ANSWER_SECTION, domain, rrset);
assert(rrset->rr_count > 0);
if (added) {
/* only process first CNAME record */
domain_type *closest_match = rdata_atom_domain(rrset->rrs[0].rdatas[0]);
domain_type *closest_encloser = closest_match;
zone_type* origzone = q->zone;
++q->cname_count;
answer_lookup_zone(nsd, q, answer, closest_match->number,
closest_match == closest_encloser,
closest_match, closest_encloser,
domain_dname(closest_match));
q->zone = origzone;
}
return;
} else {
answer_nodata(q, answer, original);
return;
}
if (q->qclass != CLASS_ANY && q->zone->ns_rrset && answer_needs_ns(q)
&& !minimal_responses) {
add_rrset(q, answer, OPTIONAL_AUTHORITY_SECTION, q->zone->apex,
q->zone->ns_rrset);
}
}
/*
* Answer with authoritative data. If a wildcard is matched the owner
* name will be expanded to the domain name specified by
* DOMAIN_NUMBER. DOMAIN_NUMBER 0 (zero) is reserved for the original
* query name.
*
* DNSSEC: Include the necessary NSEC records in case the request
* domain name does not exist and/or a wildcard match does not exist.
*/
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)
{
domain_type *match;
domain_type *original = closest_match;
domain_type *dname_ce;
domain_type *wildcard_child;
rrset_type *rrset;
#ifdef NSEC3
if(exact && domain_has_only_NSEC3(closest_match, q->zone)) {
exact = 0; /* pretend it does not exist */
if(closest_encloser->parent)
closest_encloser = closest_encloser->parent;
}
#endif /* NSEC3 */
if((dname_ce = find_dname_above(closest_encloser, q->zone)) != NULL) {
/* occlude the found data, the DNAME is closest_encloser */
closest_encloser = dname_ce;
exact = 0;
}
if (exact) {
match = closest_match;
} else if ((rrset=domain_find_rrset(closest_encloser, q->zone, TYPE_DNAME))) {
/* process DNAME */
const dname_type* name = qname;
domain_type* src = closest_encloser;
domain_type *dest = rdata_atom_domain(rrset->rrs[0].rdatas[0]);
const dname_type* newname;
size_t newnum = 0;
zone_type* origzone = q->zone;
assert(rrset->rr_count > 0);
if(domain_number != 0) /* we followed CNAMEs or DNAMEs */
name = domain_dname(closest_match);
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "expanding DNAME for q=%s", dname_to_string(name, NULL)));
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->src is %s",
domain_to_string(closest_encloser)));
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->dest is %s",
domain_to_string(dest)));
if(!add_rrset(q, answer, ANSWER_SECTION, closest_encloser, rrset)) {
/* stop if DNAME loops, when added second time */
if(dname_is_subdomain(domain_dname(dest), domain_dname(src))) {
return;
}
}
newname = dname_replace(q->region, name,
domain_dname(src), domain_dname(dest));
++q->cname_count;
if(!newname) { /* newname too long */
RCODE_SET(q->packet, RCODE_YXDOMAIN);
/* RFC 8914 - Extended DNS Errors
* 4.21. Extended DNS Error Code 0 - Other */
ASSIGN_EDE_CODE_AND_STRING_LITERAL(q->edns.ede,
EDE_OTHER, "DNAME expansion became too large");
return;
}
DEBUG(DEBUG_QUERY,2, (LOG_INFO, "->result is %s", dname_to_string(newname, NULL)));
/* follow the DNAME */
(void)namedb_lookup(nsd->db, newname, &closest_match, &closest_encloser);
/* synthesize CNAME record */
newnum = query_synthesize_cname(q, answer, name, newname,
src, closest_encloser, &closest_match, rrset->rrs[0].ttl);
if(!newnum) {
/* could not synthesize the CNAME. */
/* return previous CNAMEs to make resolver recurse for us */
return;
}
if(q->qtype == TYPE_CNAME) {
/* The synthesized CNAME is the answer to
* that query, same as BIND does for query
* of type CNAME */
return;
}
answer_lookup_zone(nsd, q, answer, newnum,
closest_match == closest_encloser,
closest_match, closest_encloser, newname);
q->zone = origzone;
return;
} else if ((wildcard_child=domain_wildcard_child(closest_encloser))!=NULL &&
wildcard_child->is_existing) {
/* Generate the domain from the wildcard. */
#ifdef RATELIMIT
q->wildcard_domain = wildcard_child;
#endif
match = (domain_type *) region_alloc(q->region,
sizeof(domain_type));
#ifdef USE_RADIX_TREE
match->rnode = NULL;
match->dname = wildcard_child->dname;
#else
memcpy(&match->node, &wildcard_child->node, sizeof(rbnode_type));
match->node.parent = NULL;
#endif
match->parent = closest_encloser;
match->wildcard_child_closest_match = match;
match->number = domain_number;
match->rrsets = wildcard_child->rrsets;
match->is_existing = wildcard_child->is_existing;
#ifdef NSEC3
match->nsec3 = wildcard_child->nsec3;
/* copy over these entries:
match->nsec3_is_exact = wildcard_child->nsec3_is_exact;
match->nsec3_cover = wildcard_child->nsec3_cover;
match->nsec3_wcard_child_cover = wildcard_child->nsec3_wcard_child_cover;
match->nsec3_ds_parent_is_exact = wildcard_child->nsec3_ds_parent_is_exact;
match->nsec3_ds_parent_cover = wildcard_child->nsec3_ds_parent_cover;
*/
if (q->edns.dnssec_ok && q->zone->nsec3_param) {
/* Only add nsec3 wildcard data when do bit is set */
nsec3_answer_wildcard(q, answer, wildcard_child, qname);
}
#endif
/*
* Remember the original domain in case a Wildcard No
* Data (3.1.3.4) response needs to be generated. In
* this particular case the wildcard IS NOT
* expanded.
*/
original = wildcard_child;
} else {
match = NULL;
}
/* Authoritative zone. */
#ifdef NSEC3
if (q->edns.dnssec_ok && q->zone->nsec3_param) {
nsec3_answer_authoritative(&match, q, answer,
closest_encloser, qname);
} else
#endif
if (q->edns.dnssec_ok && zone_is_secure(q->zone)) {
if (match != closest_encloser) {
domain_type *nsec_domain;
rrset_type *nsec_rrset;
/*
* No match found or generated from wildcard,
* include NSEC record.
*/
nsec_domain = find_covering_nsec(closest_match, q->zone, &nsec_rrset);
if (nsec_domain) {
add_rrset(q, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset);
}
}
if (!match) {
domain_type *nsec_domain;
rrset_type *nsec_rrset;
/*
* No match and no wildcard. Include NSEC
* proving there is no wildcard.
*/
if(closest_encloser && (nsec_domain =
find_covering_nsec(closest_encloser->
wildcard_child_closest_match, q->zone,
&nsec_rrset)) != NULL) {
add_rrset(q, answer, AUTHORITY_SECTION, nsec_domain, nsec_rrset);
}
}
}
#ifdef NSEC3
if (RCODE(q->packet)!=RCODE_OK) {
return; /* nsec3 collision failure */
}
#endif
if (match) {
answer_domain(nsd, q, answer, match, original);
} else {
answer_nxdomain(q, answer);
}
}
/*
* qname may be different after CNAMEs have been followed from query->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)
{
zone_type* origzone = q->zone;
q->zone = domain_find_zone(nsd->db, closest_encloser);
if (!q->zone) {
/* no zone for this */
if(q->cname_count == 0) {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC 8914 - Extended DNS Errors
* 4.21. Extended DNS Error Code 20 - Not Authoritative */
q->edns.ede = EDE_NOT_AUTHORITATIVE;
}
return;
}
assert(closest_encloser); /* otherwise, no q->zone would be found */
if(q->zone->opts && q->zone->opts->pattern
&& q->zone->opts->pattern->allow_query) {
struct acl_options *why = NULL;
/* check if it passes acl */
if(q->is_proxied && acl_check_incoming_block_proxy(
q->zone->opts->pattern->allow_query, q, &why) == -1) {
/* the proxy address is blocked */
if (verbosity >= 2) {
char address[128], proxy[128];
addr2str(&q->client_addr, address, sizeof(address));
addr2str(&q->remote_addr, proxy, sizeof(proxy));
VERBOSITY(2, (LOG_INFO, "query %s from %s via proxy %s refused because of proxy, %s %s",
dname_to_string(q->qname, NULL),
address, proxy,
(why?why->ip_address_spec:"."),
(why ? ( why->nokey ? "NOKEY"
: why->blocked ? "BLOCKED"
: why->key_name )
: "no acl matches")));
}
/* no zone for this */
if(q->cname_count == 0) {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.19. Extended DNS Error Code 18 - Prohibited */
q->edns.ede = EDE_PROHIBITED;
}
return;
}
if(acl_check_incoming(
q->zone->opts->pattern->allow_query, q, &why) != -1) {
assert(why);
DEBUG(DEBUG_QUERY,1, (LOG_INFO, "query %s passed acl %s %s",
dname_to_string(q->qname, NULL),
why->ip_address_spec,
why->nokey?"NOKEY":
(why->blocked?"BLOCKED":why->key_name)));
} else {
if (verbosity >= 2) {
char address[128];
addr2str(&q->client_addr, address, sizeof(address));
VERBOSITY(2, (LOG_INFO, "query %s from %s refused, %s %s",
dname_to_string(q->qname, NULL),
address,
why ? ( why->nokey ? "NOKEY"
: why->blocked ? "BLOCKED"
: why->key_name )
: "no acl matches",
why?why->ip_address_spec:"."));
}
/* no zone for this */
if(q->cname_count == 0) {
RCODE_SET(q->packet, RCODE_REFUSE);
/* RFC8914 - Extended DNS Errors
* 4.19. Extended DNS Error Code 18 - Prohibited */
q->edns.ede = EDE_PROHIBITED;
}
return;
}
}
if(!q->zone->apex || !q->zone->soa_rrset) {
/* zone is configured but not loaded */
if(q->cname_count == 0) {
RCODE_SET(q->packet, RCODE_SERVFAIL);
/* RFC 8914 - Extended DNS Errors
* 4.15. Extended DNS Error Code 14 - Not Ready */
q->edns.ede = EDE_NOT_READY;
ASSIGN_EDE_CODE_AND_STRING_LITERAL(q->edns.ede,
EDE_NOT_READY, "Zone is configured but not loaded");
}
return;
}
/*
* If confine-to-zone is set to yes do not return additional
* information for a zone with a different apex from the query zone.
*/
if (nsd->options->confine_to_zone &&
(origzone != NULL && dname_compare(domain_dname(origzone->apex), domain_dname(q->zone->apex)) != 0)) {
return;
}
/* now move up the closest encloser until it exists, previous
* (possibly empty) closest encloser was useful to finding the zone
* (for empty zones too), but now we want actual data nodes */
if (closest_encloser && !closest_encloser->is_existing) {
exact = 0;
while (closest_encloser != NULL && !closest_encloser->is_existing)
closest_encloser = closest_encloser->parent;
}
/*
* See RFC 4035 (DNSSEC protocol) section 3.1.4.1 Responding
* to Queries for DS RRs.
*/
if (exact && q->qtype == TYPE_DS && closest_encloser == q->zone->apex) {
/*
* Type DS query at a zone cut, use the responsible
* parent zone to generate the answer if we are
* authoritative for the parent zone.
*/
zone_type *zone = domain_find_parent_zone(nsd->db, q->zone);
if (zone) {
q->zone = zone;
if(!q->zone->apex || !q->zone->soa_rrset) {
/* zone is configured but not loaded */
if(q->cname_count == 0) {
RCODE_SET(q->packet, RCODE_SERVFAIL);
/* RFC 8914 - Extended DNS Errors
* 4.15. Extended DNS Error Code 14 - Not Ready */
ASSIGN_EDE_CODE_AND_STRING_LITERAL(
q->edns.ede, EDE_NOT_READY,
"Zone is configured but not loaded");
}
return;
}
}
}
/* see if the zone has expired (for secondary zones) */
if(q->zone && q->zone->opts && q->zone->opts->pattern &&
q->zone->opts->pattern->request_xfr != 0 && !q->zone->is_ok) {
if(q->cname_count == 0) {
RCODE_SET(q->packet, RCODE_SERVFAIL);
/* RFC 8914 - Extended DNS Errors
* 4.25. Extended DNS Error Code 24 - Invalid Data */
ASSIGN_EDE_CODE_AND_STRING_LITERAL(q->edns.ede,
EDE_INVALID_DATA, "Zone has expired");
}
return;
}
if (exact && q->qtype == TYPE_DS && closest_encloser == q->zone->apex) {
/*
* Type DS query at the zone apex (and the server is
* not authoritative for the parent zone).
*/
if (q->qclass == CLASS_ANY) {
AA_CLR(q->packet);
} else {
AA_SET(q->packet);
}
answer_nodata(q, answer, closest_encloser);
} else {
q->delegation_domain = domain_find_ns_rrsets(
closest_encloser, q->zone, &q->delegation_rrset);
if(q->delegation_domain && find_dname_above(q->delegation_domain, q->zone)) {
q->delegation_domain = NULL; /* use higher DNAME */
}
if (!q->delegation_domain
|| !q->delegation_rrset
|| (exact && q->qtype == TYPE_DS && closest_encloser == q->delegation_domain))
{
if (q->qclass == CLASS_ANY) {
AA_CLR(q->packet);
} else {
AA_SET(q->packet);
}
answer_authoritative(nsd, q, answer, domain_number, exact,
closest_match, closest_encloser, qname);
}
else {
answer_delegation(q, answer);
}
}
}
static void
answer_query(struct nsd *nsd, struct query *q)
{
domain_type *closest_match;
domain_type *closest_encloser;
int exact;
uint16_t offset;
answer_type answer;
answer_init(&answer);
exact = namedb_lookup(nsd->db, q->qname, &closest_match, &closest_encloser);
answer_lookup_zone(nsd, q, &answer, 0, exact, closest_match,
closest_encloser, q->qname);
ZTATUP2(nsd, q->zone, opcode, q->opcode);
ZTATUP2(nsd, q->zone, qtype, q->qtype);
ZTATUP2(nsd, q->zone, qclass, q->qclass);
offset = dname_label_offsets(q->qname)[domain_dname(closest_encloser)->label_count - 1] + QHEADERSZ;
query_add_compression_domain(q, closest_encloser, offset);
encode_answer(q, &answer);
query_clear_compression_tables(q);
}
void
query_prepare_response(query_type *q)
{
uint16_t flags;
/*
* Preserve the data up-to the current packet's limit.
*/
buffer_set_position(q->packet, buffer_limit(q->packet));
buffer_set_limit(q->packet, buffer_capacity(q->packet));
/*
* Reserve space for the EDNS records if required.
*/
q->reserved_space = edns_reserved_space(&q->edns);
q->reserved_space += tsig_reserved_space(&q->tsig);
/* Update the flags. */
flags = FLAGS(q->packet);
flags &= 0x0100U; /* Preserve the RD flag. */
/* CD flag must be cleared for auth answers */
flags |= 0x8000U; /* Set the QR flag. */
FLAGS_SET(q->packet, flags);
}
/*
* Processes the query.
*
*/
query_state_type
query_process(query_type *q, nsd_type *nsd, uint32_t *now_p)
{
/* The query... */
nsd_rc_type rc;
query_state_type query_state;
uint16_t arcount;
/* Sanity checks */
if (buffer_limit(q->packet) < QHEADERSZ) {
/* packet too small to contain DNS header.
Now packet investigation macros will work without problems. */
return QUERY_DISCARDED;
}
if (QR(q->packet)) {
/* Not a query? Drop it on the floor. */
return QUERY_DISCARDED;
}
/* check opcode early on, because new opcodes may have different
* specification of the meaning of the rest of the packet */
q->opcode = OPCODE(q->packet);
if(q->opcode != OPCODE_QUERY && q->opcode != OPCODE_NOTIFY) {
if(query_ratelimit_err(nsd))
return QUERY_DISCARDED;
if(nsd->options->drop_updates && q->opcode == OPCODE_UPDATE)
return QUERY_DISCARDED;
return query_error(q, NSD_RC_IMPL);
}
if (RCODE(q->packet) != RCODE_OK || !process_query_section(q)) {
return query_formerr(q, nsd);
}
/* Update statistics. */
STATUP2(nsd, opcode, q->opcode);
STATUP2(nsd, qtype, q->qtype);
STATUP2(nsd, qclass, q->qclass);
if (q->opcode != OPCODE_QUERY) {
if (q->opcode == OPCODE_NOTIFY) {
return answer_notify(nsd, q);
} else {
if(query_ratelimit_err(nsd))
return QUERY_DISCARDED;
return query_error(q, NSD_RC_IMPL);
}
}
/* Dont bother to answer more than one question at once... */
if (QDCOUNT(q->packet) != 1) {
if(QDCOUNT(q->packet) == 0 && ANCOUNT(q->packet) == 0 &&
NSCOUNT(q->packet) == 0 && ARCOUNT(q->packet) == 1 &&
buffer_limit(q->packet) >= QHEADERSZ+OPT_LEN+
OPT_RDATA) {
/* add edns section to answer */
buffer_set_position(q->packet, QHEADERSZ);
if (edns_parse_record(&q->edns, q->packet, q, nsd)) {
if(process_edns(nsd, q) == NSD_RC_OK) {
int opcode = OPCODE(q->packet);
(void)query_error(q, NSD_RC_FORMAT);
query_add_optional(q, nsd, now_p);
FLAGS_SET(q->packet, FLAGS(q->packet) & 0x0100U);
/* Preserve the RD flag. Clear the rest. */
OPCODE_SET(q->packet, opcode);
QR_SET(q->packet);
return QUERY_PROCESSED;
}
}
}
FLAGS_SET(q->packet, 0);
return query_formerr(q, nsd);
}
/* Ignore settings of flags */
/* Dont allow any records in the answer or authority section...
except for IXFR queries. */
if (ANCOUNT(q->packet) != 0 ||
(q->qtype!=TYPE_IXFR && NSCOUNT(q->packet) != 0)) {
return query_formerr(q, nsd);
}
if(q->qtype==TYPE_IXFR && NSCOUNT(q->packet) > 0) {
unsigned int i; /* skip ixfr soa information data here */
unsigned int nscount = (unsigned)NSCOUNT(q->packet);
/* define a bound on the number of extraneous records allowed,
* we expect 1, a SOA serial record, and no more.
* perhaps RRSIGs (but not needed), otherwise we do not
* understand what this means. We do not want too many
* because the high iteration counts slow down. */
if(nscount > 64) return query_formerr(q, nsd);
for(i=0; i< nscount; i++)
if(!packet_skip_rr(q->packet, 0))
return query_formerr(q, nsd);
}
arcount = ARCOUNT(q->packet);
/* A TSIG RR is not allowed before the EDNS OPT RR.
* In RFC6891 (about EDNS) it says:
* "The placement flexibility for the OPT RR does not
* override the need for the TSIG or SIG(0) RRs to be
* the last in the additional section whenever they are
* present."
* And in RFC8945 (about TSIG) it says:
* "If multiple TSIG records are detected or a TSIG record is
* present in any other position, the DNS message is dropped
* and a response with RCODE 1 (FORMERR) MUST be returned."
*/
/* See if there is an OPT RR. */
if (arcount > 0) {
if (edns_parse_record(&q->edns, q->packet, q, nsd))
--arcount;
}
/* See if there is a TSIG RR. */
if (arcount > 0 && q->tsig.status == TSIG_NOT_PRESENT) {
/* see if tsig is after the edns record */
if (!tsig_parse_rr(&q->tsig, q->packet))
return query_formerr(q, nsd);
if(q->tsig.status != TSIG_NOT_PRESENT)
--arcount;
}
/* If more RRs left in Add. Section, FORMERR. */
if (arcount > 0) {
return query_formerr(q, nsd);
}
/* Do we have any trailing garbage? */
#ifdef STRICT_MESSAGE_PARSE
if (buffer_remaining(q->packet) > 0) {
/* If we're strict.... */
return query_formerr(q, nsd);
}
#endif
/* Remove trailing garbage. */
buffer_set_limit(q->packet, buffer_position(q->packet));
rc = process_tsig(q);
if (rc != NSD_RC_OK) {
return query_error(q, rc);
}
rc = process_edns(nsd, q);
if (rc != NSD_RC_OK) {
/* We should not return FORMERR, but BADVERS (=16).
* BADVERS is created with Ext. RCODE, followed by RCODE.
* Ext. RCODE is set to 1, RCODE must be 0 (getting 0x10 = 16).
* Thus RCODE = NOERROR = NSD_RC_OK. */
RCODE_SET(q->packet, NSD_RC_OK);
buffer_clear(q->packet);
buffer_set_position(q->packet,
QHEADERSZ + 4 + q->qname->name_size);
QR_SET(q->packet);
AD_CLR(q->packet);
QDCOUNT_SET(q->packet, 1);
ANCOUNT_SET(q->packet, 0);
NSCOUNT_SET(q->packet, 0);
ARCOUNT_SET(q->packet, 0);
return QUERY_PROCESSED;
}
if (q->edns.cookie_status == COOKIE_UNVERIFIED)
cookie_verify(q, nsd, now_p);
query_prepare_response(q);
if (q->qclass != CLASS_IN && q->qclass != CLASS_ANY) {
if (q->qclass == CLASS_CH) {
return answer_chaos(nsd, q);
} else {
/* RFC8914 - Extended DNS Errors
* 4.22. Extended DNS Error Code 21 - Not Supported */
q->edns.ede = EDE_NOT_SUPPORTED;
return query_error(q, RCODE_REFUSE);
}
}
query_state = answer_axfr_ixfr(nsd, q);
if (query_state == QUERY_PROCESSED || query_state == QUERY_IN_AXFR
|| query_state == QUERY_IN_IXFR) {
return query_state;
}
if(q->qtype == TYPE_ANY && nsd->options->refuse_any && !q->tcp) {
TC_SET(q->packet);
return query_error(q, NSD_RC_OK);
}
answer_query(nsd, q);
return QUERY_PROCESSED;
}
void
query_add_optional(query_type *q, nsd_type *nsd, uint32_t *now_p)
{
struct edns_data *edns = &nsd->edns_ipv4;
#if defined(INET6)
if (q->client_addr.ss_family == AF_INET6) {
edns = &nsd->edns_ipv6;
}
#endif
if (RCODE(q->packet) == RCODE_FORMAT) {
return;
}
switch (q->edns.status) {
case EDNS_NOT_PRESENT:
break;
case EDNS_OK:
if (q->edns.dnssec_ok) edns->ok[7] = 0x80;
else edns->ok[7] = 0x00;
buffer_write(q->packet, edns->ok, OPT_LEN);
/* Add Extended DNS Error (RFC8914)
* to verify that we stay in bounds */
if (q->edns.ede >= 0)
q->edns.opt_reserved_space +=
6 + ( q->edns.ede_text_len
? q->edns.ede_text_len : 0);
if(q->edns.opt_reserved_space == 0 || !buffer_available(
q->packet, 2+q->edns.opt_reserved_space)) {
/* fill with NULLs */
buffer_write(q->packet, edns->rdata_none, OPT_RDATA);
} else {
/* rdata length */
buffer_write_u16(q->packet, q->edns.opt_reserved_space);
/* edns options */
if(q->edns.nsid) {
/* nsid opt header */
buffer_write(q->packet, edns->nsid, OPT_HDR);
/* nsid payload */
buffer_write(q->packet, nsd->nsid, nsd->nsid_len);
}
if(q->edns.cookie_status != COOKIE_NOT_PRESENT) {
/* cookie opt header */
buffer_write(q->packet, edns->cookie, OPT_HDR);
/* cookie payload */
cookie_create(q, nsd, now_p);
buffer_write(q->packet, q->edns.cookie, 24);
}
/* Append Extended DNS Error (RFC8914) option if needed */
if (q->edns.ede >= 0) { /* < 0 means no EDE */
/* OPTION-CODE */
buffer_write_u16(q->packet, EDE_CODE);
/* OPTION-LENGTH */
buffer_write_u16(q->packet,
2 + ( q->edns.ede_text_len
? q->edns.ede_text_len : 0));
/* INFO-CODE */
buffer_write_u16(q->packet, q->edns.ede);
/* EXTRA-TEXT */
if (q->edns.ede_text_len)
buffer_write(q->packet,
q->edns.ede_text,
q->edns.ede_text_len);
}
}
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1);
STATUP(nsd, edns);
ZTATUP(nsd, q->zone, edns);
break;
case EDNS_ERROR:
if (q->edns.dnssec_ok) edns->error[7] = 0x80;
else edns->error[7] = 0x00;
buffer_write(q->packet, edns->error, OPT_LEN);
buffer_write(q->packet, edns->rdata_none, OPT_RDATA);
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1);
STATUP(nsd, ednserr);
ZTATUP(nsd, q->zone, ednserr);
break;
}
if (q->tsig.status != TSIG_NOT_PRESENT) {
if (q->tsig.status == TSIG_ERROR ||
q->tsig.error_code != TSIG_ERROR_NOERROR) {
tsig_error_reply(&q->tsig);
tsig_append_rr(&q->tsig, q->packet);
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1);
} else if(q->tsig.status == TSIG_OK &&
q->tsig.error_code == TSIG_ERROR_NOERROR)
{
if(q->tsig_prepare_it)
tsig_prepare(&q->tsig);
if(q->tsig_update_it)
tsig_update(&q->tsig, q->packet, buffer_position(q->packet));
if(q->tsig_sign_it) {
tsig_sign(&q->tsig);
tsig_append_rr(&q->tsig, q->packet);
ARCOUNT_SET(q->packet, ARCOUNT(q->packet) + 1);
}
}
}
}
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