2 This file is part of systemd.
4 Copyright 2014 Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 #include "alloc-util.h"
21 #include "dns-domain.h"
22 #include "resolved-dns-packet.h"
23 #include "string-table.h"
25 #include "unaligned.h"
29 #define EDNS0_OPT_DO (1<<15)
31 typedef struct DnsPacketRewinder
{
36 static void rewind_dns_packet(DnsPacketRewinder
*rewinder
) {
38 dns_packet_rewind(rewinder
->packet
, rewinder
->saved_rindex
);
41 #define INIT_REWINDER(rewinder, p) do { rewinder.packet = p; rewinder.saved_rindex = p->rindex; } while (0)
42 #define CANCEL_REWINDER(rewinder) do { rewinder.packet = NULL; } while (0)
44 int dns_packet_new(DnsPacket
**ret
, DnsProtocol protocol
, size_t mtu
) {
50 if (mtu
<= UDP_PACKET_HEADER_SIZE
)
51 a
= DNS_PACKET_SIZE_START
;
53 a
= mtu
- UDP_PACKET_HEADER_SIZE
;
55 if (a
< DNS_PACKET_HEADER_SIZE
)
56 a
= DNS_PACKET_HEADER_SIZE
;
58 /* round up to next page size */
59 a
= PAGE_ALIGN(ALIGN(sizeof(DnsPacket
)) + a
) - ALIGN(sizeof(DnsPacket
));
61 /* make sure we never allocate more than useful */
62 if (a
> DNS_PACKET_SIZE_MAX
)
63 a
= DNS_PACKET_SIZE_MAX
;
65 p
= malloc0(ALIGN(sizeof(DnsPacket
)) + a
);
69 p
->size
= p
->rindex
= DNS_PACKET_HEADER_SIZE
;
71 p
->protocol
= protocol
;
72 p
->opt_start
= p
->opt_size
= (size_t) -1;
80 void dns_packet_set_flags(DnsPacket
*p
, bool dnssec_checking_disabled
, bool truncated
) {
86 h
= DNS_PACKET_HEADER(p
);
89 case DNS_PROTOCOL_LLMNR
:
92 h
->flags
= htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
103 case DNS_PROTOCOL_MDNS
:
104 h
->flags
= htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
108 0 /* rd (ask for recursion) */,
118 h
->flags
= htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
122 1 /* rd (ask for recursion) */,
125 dnssec_checking_disabled
/* cd */,
130 int dns_packet_new_query(DnsPacket
**ret
, DnsProtocol protocol
, size_t mtu
, bool dnssec_checking_disabled
) {
136 r
= dns_packet_new(&p
, protocol
, mtu
);
140 /* Always set the TC bit to 0 initially.
141 * If there are multiple packets later, we'll update the bit shortly before sending.
143 dns_packet_set_flags(p
, dnssec_checking_disabled
, false);
149 DnsPacket
*dns_packet_ref(DnsPacket
*p
) {
154 assert(!p
->on_stack
);
156 assert(p
->n_ref
> 0);
161 static void dns_packet_free(DnsPacket
*p
) {
166 dns_question_unref(p
->question
);
167 dns_answer_unref(p
->answer
);
168 dns_resource_record_unref(p
->opt
);
170 while ((s
= hashmap_steal_first_key(p
->names
)))
172 hashmap_free(p
->names
);
180 DnsPacket
*dns_packet_unref(DnsPacket
*p
) {
184 assert(p
->n_ref
> 0);
186 dns_packet_unref(p
->more
);
196 int dns_packet_validate(DnsPacket
*p
) {
199 if (p
->size
< DNS_PACKET_HEADER_SIZE
)
202 if (p
->size
> DNS_PACKET_SIZE_MAX
)
208 int dns_packet_validate_reply(DnsPacket
*p
) {
213 r
= dns_packet_validate(p
);
217 if (DNS_PACKET_QR(p
) != 1)
220 if (DNS_PACKET_OPCODE(p
) != 0)
223 switch (p
->protocol
) {
225 case DNS_PROTOCOL_LLMNR
:
226 /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */
227 if (DNS_PACKET_QDCOUNT(p
) != 1)
232 case DNS_PROTOCOL_MDNS
:
233 /* RFC 6762, Section 18 */
234 if (DNS_PACKET_RCODE(p
) != 0)
246 int dns_packet_validate_query(DnsPacket
*p
) {
251 r
= dns_packet_validate(p
);
255 if (DNS_PACKET_QR(p
) != 0)
258 if (DNS_PACKET_OPCODE(p
) != 0)
261 if (DNS_PACKET_TC(p
))
264 switch (p
->protocol
) {
266 case DNS_PROTOCOL_LLMNR
:
267 case DNS_PROTOCOL_DNS
:
268 /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */
269 if (DNS_PACKET_QDCOUNT(p
) != 1)
272 /* RFC 4795, Section 2.1.1. says to discard all queries with ANCOUNT != 0 */
273 if (DNS_PACKET_ANCOUNT(p
) > 0)
276 /* RFC 4795, Section 2.1.1. says to discard all queries with NSCOUNT != 0 */
277 if (DNS_PACKET_NSCOUNT(p
) > 0)
282 case DNS_PROTOCOL_MDNS
:
283 /* RFC 6762, Section 18 */
284 if (DNS_PACKET_AA(p
) != 0 ||
285 DNS_PACKET_RD(p
) != 0 ||
286 DNS_PACKET_RA(p
) != 0 ||
287 DNS_PACKET_AD(p
) != 0 ||
288 DNS_PACKET_CD(p
) != 0 ||
289 DNS_PACKET_RCODE(p
) != 0)
301 static int dns_packet_extend(DnsPacket
*p
, size_t add
, void **ret
, size_t *start
) {
304 if (p
->size
+ add
> p
->allocated
) {
307 a
= PAGE_ALIGN((p
->size
+ add
) * 2);
308 if (a
> DNS_PACKET_SIZE_MAX
)
309 a
= DNS_PACKET_SIZE_MAX
;
311 if (p
->size
+ add
> a
)
317 d
= realloc(p
->_data
, a
);
323 p
->_data
= malloc(a
);
327 memcpy(p
->_data
, (uint8_t*) p
+ ALIGN(sizeof(DnsPacket
)), p
->size
);
328 memzero((uint8_t*) p
->_data
+ p
->size
, a
- p
->size
);
338 *ret
= (uint8_t*) DNS_PACKET_DATA(p
) + p
->size
;
344 void dns_packet_truncate(DnsPacket
*p
, size_t sz
) {
354 HASHMAP_FOREACH_KEY(n
, s
, p
->names
, i
) {
356 if (PTR_TO_SIZE(n
) < sz
)
359 hashmap_remove(p
->names
, s
);
366 int dns_packet_append_blob(DnsPacket
*p
, const void *d
, size_t l
, size_t *start
) {
372 r
= dns_packet_extend(p
, l
, &q
, start
);
380 int dns_packet_append_uint8(DnsPacket
*p
, uint8_t v
, size_t *start
) {
386 r
= dns_packet_extend(p
, sizeof(uint8_t), &d
, start
);
390 ((uint8_t*) d
)[0] = v
;
395 int dns_packet_append_uint16(DnsPacket
*p
, uint16_t v
, size_t *start
) {
401 r
= dns_packet_extend(p
, sizeof(uint16_t), &d
, start
);
405 unaligned_write_be16(d
, v
);
410 int dns_packet_append_uint32(DnsPacket
*p
, uint32_t v
, size_t *start
) {
416 r
= dns_packet_extend(p
, sizeof(uint32_t), &d
, start
);
420 unaligned_write_be32(d
, v
);
425 int dns_packet_append_string(DnsPacket
*p
, const char *s
, size_t *start
) {
429 return dns_packet_append_raw_string(p
, s
, strlen(s
), start
);
432 int dns_packet_append_raw_string(DnsPacket
*p
, const void *s
, size_t size
, size_t *start
) {
437 assert(s
|| size
== 0);
442 r
= dns_packet_extend(p
, 1 + size
, &d
, start
);
446 ((uint8_t*) d
)[0] = (uint8_t) size
;
448 memcpy_safe(((uint8_t*) d
) + 1, s
, size
);
453 int dns_packet_append_label(DnsPacket
*p
, const char *d
, size_t l
, bool canonical_candidate
, size_t *start
) {
457 /* Append a label to a packet. Optionally, does this in DNSSEC
458 * canonical form, if this label is marked as a candidate for
459 * it, and the canonical form logic is enabled for the
465 if (l
> DNS_LABEL_MAX
)
468 r
= dns_packet_extend(p
, 1 + l
, (void**) &w
, start
);
472 *(w
++) = (uint8_t) l
;
474 if (p
->canonical_form
&& canonical_candidate
) {
477 /* Generate in canonical form, as defined by DNSSEC
478 * RFC 4034, Section 6.2, i.e. all lower-case. */
480 for (i
= 0; i
< l
; i
++)
481 w
[i
] = (uint8_t) ascii_tolower(d
[i
]);
483 /* Otherwise, just copy the string unaltered. This is
484 * essential for DNS-SD, where the casing of labels
485 * matters and needs to be retained. */
491 int dns_packet_append_name(
494 bool allow_compression
,
495 bool canonical_candidate
,
504 if (p
->refuse_compression
)
505 allow_compression
= false;
507 saved_size
= p
->size
;
509 while (!dns_name_is_root(name
)) {
510 const char *z
= name
;
511 char label
[DNS_LABEL_MAX
];
514 if (allow_compression
)
515 n
= PTR_TO_SIZE(hashmap_get(p
->names
, name
));
520 r
= dns_packet_append_uint16(p
, 0xC000 | n
, NULL
);
528 r
= dns_label_unescape(&name
, label
, sizeof(label
));
532 r
= dns_packet_append_label(p
, label
, r
, canonical_candidate
, &n
);
536 if (allow_compression
) {
537 _cleanup_free_
char *s
= NULL
;
545 r
= hashmap_ensure_allocated(&p
->names
, &dns_name_hash_ops
);
549 r
= hashmap_put(p
->names
, s
, SIZE_TO_PTR(n
));
557 r
= dns_packet_append_uint8(p
, 0, NULL
);
568 dns_packet_truncate(p
, saved_size
);
572 int dns_packet_append_key(DnsPacket
*p
, const DnsResourceKey
*k
, size_t *start
) {
579 saved_size
= p
->size
;
581 r
= dns_packet_append_name(p
, dns_resource_key_name(k
), true, true, NULL
);
585 r
= dns_packet_append_uint16(p
, k
->type
, NULL
);
589 r
= dns_packet_append_uint16(p
, k
->class, NULL
);
599 dns_packet_truncate(p
, saved_size
);
603 static int dns_packet_append_type_window(DnsPacket
*p
, uint8_t window
, uint8_t length
, const uint8_t *types
, size_t *start
) {
611 saved_size
= p
->size
;
613 r
= dns_packet_append_uint8(p
, window
, NULL
);
617 r
= dns_packet_append_uint8(p
, length
, NULL
);
621 r
= dns_packet_append_blob(p
, types
, length
, NULL
);
630 dns_packet_truncate(p
, saved_size
);
634 static int dns_packet_append_types(DnsPacket
*p
, Bitmap
*types
, size_t *start
) {
638 uint8_t bitmaps
[32] = {};
645 saved_size
= p
->size
;
647 BITMAP_FOREACH(n
, types
, i
) {
650 if ((n
>> 8) != window
&& bitmaps
[entry
/ 8] != 0) {
651 r
= dns_packet_append_type_window(p
, window
, entry
/ 8 + 1, bitmaps
, NULL
);
661 bitmaps
[entry
/ 8] |= 1 << (7 - (entry
% 8));
664 if (bitmaps
[entry
/ 8] != 0) {
665 r
= dns_packet_append_type_window(p
, window
, entry
/ 8 + 1, bitmaps
, NULL
);
675 dns_packet_truncate(p
, saved_size
);
679 /* Append the OPT pseudo-RR described in RFC6891 */
680 int dns_packet_append_opt(DnsPacket
*p
, uint16_t max_udp_size
, bool edns0_do
, int rcode
, size_t *start
) {
685 /* we must never advertise supported packet size smaller than the legacy max */
686 assert(max_udp_size
>= DNS_PACKET_UNICAST_SIZE_MAX
);
688 assert(rcode
<= _DNS_RCODE_MAX
);
690 if (p
->opt_start
!= (size_t) -1)
693 assert(p
->opt_size
== (size_t) -1);
695 saved_size
= p
->size
;
698 r
= dns_packet_append_uint8(p
, 0, NULL
);
703 r
= dns_packet_append_uint16(p
, DNS_TYPE_OPT
, NULL
);
707 /* class: maximum udp packet that can be received */
708 r
= dns_packet_append_uint16(p
, max_udp_size
, NULL
);
712 /* extended RCODE and VERSION */
713 r
= dns_packet_append_uint16(p
, ((uint16_t) rcode
& 0x0FF0) << 4, NULL
);
717 /* flags: DNSSEC OK (DO), see RFC3225 */
718 r
= dns_packet_append_uint16(p
, edns0_do
? EDNS0_OPT_DO
: 0, NULL
);
723 if (edns0_do
&& !DNS_PACKET_QR(p
)) {
724 /* If DO is on and this is not a reply, also append RFC6975 Algorithm data */
726 static const uint8_t rfc6975
[] = {
728 0, 5, /* OPTION_CODE: DAU */
729 0, 6, /* LIST_LENGTH */
730 DNSSEC_ALGORITHM_RSASHA1
,
731 DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1
,
732 DNSSEC_ALGORITHM_RSASHA256
,
733 DNSSEC_ALGORITHM_RSASHA512
,
734 DNSSEC_ALGORITHM_ECDSAP256SHA256
,
735 DNSSEC_ALGORITHM_ECDSAP384SHA384
,
737 0, 6, /* OPTION_CODE: DHU */
738 0, 3, /* LIST_LENGTH */
740 DNSSEC_DIGEST_SHA256
,
741 DNSSEC_DIGEST_SHA384
,
743 0, 7, /* OPTION_CODE: N3U */
744 0, 1, /* LIST_LENGTH */
745 NSEC3_ALGORITHM_SHA1
,
748 r
= dns_packet_append_uint16(p
, sizeof(rfc6975
), NULL
);
752 r
= dns_packet_append_blob(p
, rfc6975
, sizeof(rfc6975
), NULL
);
754 r
= dns_packet_append_uint16(p
, 0, NULL
);
758 DNS_PACKET_HEADER(p
)->arcount
= htobe16(DNS_PACKET_ARCOUNT(p
) + 1);
760 p
->opt_start
= saved_size
;
761 p
->opt_size
= p
->size
- saved_size
;
769 dns_packet_truncate(p
, saved_size
);
773 int dns_packet_truncate_opt(DnsPacket
*p
) {
776 if (p
->opt_start
== (size_t) -1) {
777 assert(p
->opt_size
== (size_t) -1);
781 assert(p
->opt_size
!= (size_t) -1);
782 assert(DNS_PACKET_ARCOUNT(p
) > 0);
784 if (p
->opt_start
+ p
->opt_size
!= p
->size
)
787 dns_packet_truncate(p
, p
->opt_start
);
788 DNS_PACKET_HEADER(p
)->arcount
= htobe16(DNS_PACKET_ARCOUNT(p
) - 1);
789 p
->opt_start
= p
->opt_size
= (size_t) -1;
794 int dns_packet_append_rr(DnsPacket
*p
, const DnsResourceRecord
*rr
, size_t *start
, size_t *rdata_start
) {
796 size_t saved_size
, rdlength_offset
, end
, rdlength
, rds
;
802 saved_size
= p
->size
;
804 r
= dns_packet_append_key(p
, rr
->key
, NULL
);
808 r
= dns_packet_append_uint32(p
, rr
->ttl
, NULL
);
812 /* Initially we write 0 here */
813 r
= dns_packet_append_uint16(p
, 0, &rdlength_offset
);
817 rds
= p
->size
- saved_size
;
819 switch (rr
->unparseable
? _DNS_TYPE_INVALID
: rr
->key
->type
) {
822 r
= dns_packet_append_uint16(p
, rr
->srv
.priority
, NULL
);
826 r
= dns_packet_append_uint16(p
, rr
->srv
.weight
, NULL
);
830 r
= dns_packet_append_uint16(p
, rr
->srv
.port
, NULL
);
834 r
= dns_packet_append_name(p
, rr
->srv
.name
, true, false, NULL
);
841 r
= dns_packet_append_name(p
, rr
->ptr
.name
, true, false, NULL
);
845 r
= dns_packet_append_string(p
, rr
->hinfo
.cpu
, NULL
);
849 r
= dns_packet_append_string(p
, rr
->hinfo
.os
, NULL
);
852 case DNS_TYPE_SPF
: /* exactly the same as TXT */
855 if (!rr
->txt
.items
) {
856 /* RFC 6763, section 6.1 suggests to generate
857 * single empty string for an empty array. */
859 r
= dns_packet_append_raw_string(p
, NULL
, 0, NULL
);
865 LIST_FOREACH(items
, i
, rr
->txt
.items
) {
866 r
= dns_packet_append_raw_string(p
, i
->data
, i
->length
, NULL
);
876 r
= dns_packet_append_blob(p
, &rr
->a
.in_addr
, sizeof(struct in_addr
), NULL
);
880 r
= dns_packet_append_blob(p
, &rr
->aaaa
.in6_addr
, sizeof(struct in6_addr
), NULL
);
884 r
= dns_packet_append_name(p
, rr
->soa
.mname
, true, false, NULL
);
888 r
= dns_packet_append_name(p
, rr
->soa
.rname
, true, false, NULL
);
892 r
= dns_packet_append_uint32(p
, rr
->soa
.serial
, NULL
);
896 r
= dns_packet_append_uint32(p
, rr
->soa
.refresh
, NULL
);
900 r
= dns_packet_append_uint32(p
, rr
->soa
.retry
, NULL
);
904 r
= dns_packet_append_uint32(p
, rr
->soa
.expire
, NULL
);
908 r
= dns_packet_append_uint32(p
, rr
->soa
.minimum
, NULL
);
912 r
= dns_packet_append_uint16(p
, rr
->mx
.priority
, NULL
);
916 r
= dns_packet_append_name(p
, rr
->mx
.exchange
, true, false, NULL
);
920 r
= dns_packet_append_uint8(p
, rr
->loc
.version
, NULL
);
924 r
= dns_packet_append_uint8(p
, rr
->loc
.size
, NULL
);
928 r
= dns_packet_append_uint8(p
, rr
->loc
.horiz_pre
, NULL
);
932 r
= dns_packet_append_uint8(p
, rr
->loc
.vert_pre
, NULL
);
936 r
= dns_packet_append_uint32(p
, rr
->loc
.latitude
, NULL
);
940 r
= dns_packet_append_uint32(p
, rr
->loc
.longitude
, NULL
);
944 r
= dns_packet_append_uint32(p
, rr
->loc
.altitude
, NULL
);
948 r
= dns_packet_append_uint16(p
, rr
->ds
.key_tag
, NULL
);
952 r
= dns_packet_append_uint8(p
, rr
->ds
.algorithm
, NULL
);
956 r
= dns_packet_append_uint8(p
, rr
->ds
.digest_type
, NULL
);
960 r
= dns_packet_append_blob(p
, rr
->ds
.digest
, rr
->ds
.digest_size
, NULL
);
964 r
= dns_packet_append_uint8(p
, rr
->sshfp
.algorithm
, NULL
);
968 r
= dns_packet_append_uint8(p
, rr
->sshfp
.fptype
, NULL
);
972 r
= dns_packet_append_blob(p
, rr
->sshfp
.fingerprint
, rr
->sshfp
.fingerprint_size
, NULL
);
975 case DNS_TYPE_DNSKEY
:
976 r
= dns_packet_append_uint16(p
, rr
->dnskey
.flags
, NULL
);
980 r
= dns_packet_append_uint8(p
, rr
->dnskey
.protocol
, NULL
);
984 r
= dns_packet_append_uint8(p
, rr
->dnskey
.algorithm
, NULL
);
988 r
= dns_packet_append_blob(p
, rr
->dnskey
.key
, rr
->dnskey
.key_size
, NULL
);
992 r
= dns_packet_append_uint16(p
, rr
->rrsig
.type_covered
, NULL
);
996 r
= dns_packet_append_uint8(p
, rr
->rrsig
.algorithm
, NULL
);
1000 r
= dns_packet_append_uint8(p
, rr
->rrsig
.labels
, NULL
);
1004 r
= dns_packet_append_uint32(p
, rr
->rrsig
.original_ttl
, NULL
);
1008 r
= dns_packet_append_uint32(p
, rr
->rrsig
.expiration
, NULL
);
1012 r
= dns_packet_append_uint32(p
, rr
->rrsig
.inception
, NULL
);
1016 r
= dns_packet_append_uint16(p
, rr
->rrsig
.key_tag
, NULL
);
1020 r
= dns_packet_append_name(p
, rr
->rrsig
.signer
, false, true, NULL
);
1024 r
= dns_packet_append_blob(p
, rr
->rrsig
.signature
, rr
->rrsig
.signature_size
, NULL
);
1028 r
= dns_packet_append_name(p
, rr
->nsec
.next_domain_name
, false, false, NULL
);
1032 r
= dns_packet_append_types(p
, rr
->nsec
.types
, NULL
);
1038 case DNS_TYPE_NSEC3
:
1039 r
= dns_packet_append_uint8(p
, rr
->nsec3
.algorithm
, NULL
);
1043 r
= dns_packet_append_uint8(p
, rr
->nsec3
.flags
, NULL
);
1047 r
= dns_packet_append_uint16(p
, rr
->nsec3
.iterations
, NULL
);
1051 r
= dns_packet_append_uint8(p
, rr
->nsec3
.salt_size
, NULL
);
1055 r
= dns_packet_append_blob(p
, rr
->nsec3
.salt
, rr
->nsec3
.salt_size
, NULL
);
1059 r
= dns_packet_append_uint8(p
, rr
->nsec3
.next_hashed_name_size
, NULL
);
1063 r
= dns_packet_append_blob(p
, rr
->nsec3
.next_hashed_name
, rr
->nsec3
.next_hashed_name_size
, NULL
);
1067 r
= dns_packet_append_types(p
, rr
->nsec3
.types
, NULL
);
1074 r
= dns_packet_append_uint8(p
, rr
->tlsa
.cert_usage
, NULL
);
1078 r
= dns_packet_append_uint8(p
, rr
->tlsa
.selector
, NULL
);
1082 r
= dns_packet_append_uint8(p
, rr
->tlsa
.matching_type
, NULL
);
1086 r
= dns_packet_append_blob(p
, rr
->tlsa
.data
, rr
->tlsa
.data_size
, NULL
);
1090 r
= dns_packet_append_uint8(p
, rr
->caa
.flags
, NULL
);
1094 r
= dns_packet_append_string(p
, rr
->caa
.tag
, NULL
);
1098 r
= dns_packet_append_blob(p
, rr
->caa
.value
, rr
->caa
.value_size
, NULL
);
1102 case DNS_TYPE_OPENPGPKEY
:
1103 case _DNS_TYPE_INVALID
: /* unparseable */
1106 r
= dns_packet_append_blob(p
, rr
->generic
.data
, rr
->generic
.data_size
, NULL
);
1112 /* Let's calculate the actual data size and update the field */
1113 rdlength
= p
->size
- rdlength_offset
- sizeof(uint16_t);
1114 if (rdlength
> 0xFFFF) {
1120 p
->size
= rdlength_offset
;
1121 r
= dns_packet_append_uint16(p
, rdlength
, NULL
);
1127 *start
= saved_size
;
1135 dns_packet_truncate(p
, saved_size
);
1139 int dns_packet_append_question(DnsPacket
*p
, DnsQuestion
*q
) {
1140 DnsResourceKey
*key
;
1145 DNS_QUESTION_FOREACH(key
, q
) {
1146 r
= dns_packet_append_key(p
, key
, NULL
);
1154 int dns_packet_append_answer(DnsPacket
*p
, DnsAnswer
*a
) {
1155 DnsResourceRecord
*rr
;
1160 DNS_ANSWER_FOREACH(rr
, a
) {
1161 r
= dns_packet_append_rr(p
, rr
, NULL
, NULL
);
1169 int dns_packet_read(DnsPacket
*p
, size_t sz
, const void **ret
, size_t *start
) {
1172 if (p
->rindex
+ sz
> p
->size
)
1176 *ret
= (uint8_t*) DNS_PACKET_DATA(p
) + p
->rindex
;
1185 void dns_packet_rewind(DnsPacket
*p
, size_t idx
) {
1187 assert(idx
<= p
->size
);
1188 assert(idx
>= DNS_PACKET_HEADER_SIZE
);
1193 int dns_packet_read_blob(DnsPacket
*p
, void *d
, size_t sz
, size_t *start
) {
1200 r
= dns_packet_read(p
, sz
, &q
, start
);
1208 static int dns_packet_read_memdup(
1209 DnsPacket
*p
, size_t size
,
1210 void **ret
, size_t *ret_size
,
1211 size_t *ret_start
) {
1220 r
= dns_packet_read(p
, size
, &src
, &start
);
1229 copy
= memdup(src
, size
);
1244 int dns_packet_read_uint8(DnsPacket
*p
, uint8_t *ret
, size_t *start
) {
1250 r
= dns_packet_read(p
, sizeof(uint8_t), &d
, start
);
1254 *ret
= ((uint8_t*) d
)[0];
1258 int dns_packet_read_uint16(DnsPacket
*p
, uint16_t *ret
, size_t *start
) {
1264 r
= dns_packet_read(p
, sizeof(uint16_t), &d
, start
);
1268 *ret
= unaligned_read_be16(d
);
1273 int dns_packet_read_uint32(DnsPacket
*p
, uint32_t *ret
, size_t *start
) {
1279 r
= dns_packet_read(p
, sizeof(uint32_t), &d
, start
);
1283 *ret
= unaligned_read_be32(d
);
1288 int dns_packet_read_string(DnsPacket
*p
, char **ret
, size_t *start
) {
1289 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
;
1296 INIT_REWINDER(rewinder
, p
);
1298 r
= dns_packet_read_uint8(p
, &c
, NULL
);
1302 r
= dns_packet_read(p
, c
, &d
, NULL
);
1306 if (memchr(d
, 0, c
))
1313 if (!utf8_is_valid(t
)) {
1321 *start
= rewinder
.saved_rindex
;
1322 CANCEL_REWINDER(rewinder
);
1327 int dns_packet_read_raw_string(DnsPacket
*p
, const void **ret
, size_t *size
, size_t *start
) {
1328 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
;
1333 INIT_REWINDER(rewinder
, p
);
1335 r
= dns_packet_read_uint8(p
, &c
, NULL
);
1339 r
= dns_packet_read(p
, c
, ret
, NULL
);
1346 *start
= rewinder
.saved_rindex
;
1347 CANCEL_REWINDER(rewinder
);
1352 int dns_packet_read_name(
1355 bool allow_compression
,
1358 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
;
1359 size_t after_rindex
= 0, jump_barrier
;
1360 _cleanup_free_
char *ret
= NULL
;
1361 size_t n
= 0, allocated
= 0;
1367 INIT_REWINDER(rewinder
, p
);
1368 jump_barrier
= p
->rindex
;
1370 if (p
->refuse_compression
)
1371 allow_compression
= false;
1376 r
= dns_packet_read_uint8(p
, &c
, NULL
);
1387 r
= dns_packet_read(p
, c
, (const void**) &label
, NULL
);
1391 if (!GREEDY_REALLOC(ret
, allocated
, n
+ !first
+ DNS_LABEL_ESCAPED_MAX
))
1399 r
= dns_label_escape(label
, c
, ret
+ n
, DNS_LABEL_ESCAPED_MAX
);
1405 } else if (allow_compression
&& (c
& 0xc0) == 0xc0) {
1409 r
= dns_packet_read_uint8(p
, &d
, NULL
);
1413 ptr
= (uint16_t) (c
& ~0xc0) << 8 | (uint16_t) d
;
1414 if (ptr
< DNS_PACKET_HEADER_SIZE
|| ptr
>= jump_barrier
)
1417 if (after_rindex
== 0)
1418 after_rindex
= p
->rindex
;
1420 /* Jumps are limited to a "prior occurrence" (RFC-1035 4.1.4) */
1427 if (!GREEDY_REALLOC(ret
, allocated
, n
+ 1))
1432 if (after_rindex
!= 0)
1433 p
->rindex
= after_rindex
;
1439 *start
= rewinder
.saved_rindex
;
1440 CANCEL_REWINDER(rewinder
);
1445 static int dns_packet_read_type_window(DnsPacket
*p
, Bitmap
**types
, size_t *start
) {
1448 const uint8_t *bitmap
;
1452 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
;
1457 INIT_REWINDER(rewinder
, p
);
1459 r
= bitmap_ensure_allocated(types
);
1463 r
= dns_packet_read_uint8(p
, &window
, NULL
);
1467 r
= dns_packet_read_uint8(p
, &length
, NULL
);
1471 if (length
== 0 || length
> 32)
1474 r
= dns_packet_read(p
, length
, (const void **)&bitmap
, NULL
);
1478 for (i
= 0; i
< length
; i
++) {
1479 uint8_t bitmask
= 1 << 7;
1490 if (bitmap
[i
] & bitmask
) {
1493 n
= (uint16_t) window
<< 8 | (uint16_t) bit
;
1495 /* Ignore pseudo-types. see RFC4034 section 4.1.2 */
1496 if (dns_type_is_pseudo(n
))
1499 r
= bitmap_set(*types
, n
);
1513 *start
= rewinder
.saved_rindex
;
1514 CANCEL_REWINDER(rewinder
);
1519 static int dns_packet_read_type_windows(DnsPacket
*p
, Bitmap
**types
, size_t size
, size_t *start
) {
1520 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
;
1523 INIT_REWINDER(rewinder
, p
);
1525 while (p
->rindex
< rewinder
.saved_rindex
+ size
) {
1526 r
= dns_packet_read_type_window(p
, types
, NULL
);
1530 /* don't read past end of current RR */
1531 if (p
->rindex
> rewinder
.saved_rindex
+ size
)
1535 if (p
->rindex
!= rewinder
.saved_rindex
+ size
)
1539 *start
= rewinder
.saved_rindex
;
1540 CANCEL_REWINDER(rewinder
);
1545 int dns_packet_read_key(DnsPacket
*p
, DnsResourceKey
**ret
, bool *ret_cache_flush
, size_t *start
) {
1546 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
;
1547 _cleanup_free_
char *name
= NULL
;
1548 bool cache_flush
= false;
1549 uint16_t class, type
;
1550 DnsResourceKey
*key
;
1555 INIT_REWINDER(rewinder
, p
);
1557 r
= dns_packet_read_name(p
, &name
, true, NULL
);
1561 r
= dns_packet_read_uint16(p
, &type
, NULL
);
1565 r
= dns_packet_read_uint16(p
, &class, NULL
);
1569 if (p
->protocol
== DNS_PROTOCOL_MDNS
) {
1570 /* See RFC6762, Section 10.2 */
1572 if (type
!= DNS_TYPE_OPT
&& (class & MDNS_RR_CACHE_FLUSH
)) {
1573 class &= ~MDNS_RR_CACHE_FLUSH
;
1578 key
= dns_resource_key_new_consume(class, type
, name
);
1585 if (ret_cache_flush
)
1586 *ret_cache_flush
= cache_flush
;
1588 *start
= rewinder
.saved_rindex
;
1589 CANCEL_REWINDER(rewinder
);
1594 static bool loc_size_ok(uint8_t size
) {
1595 uint8_t m
= size
>> 4, e
= size
& 0xF;
1597 return m
<= 9 && e
<= 9 && (m
> 0 || e
== 0);
1600 int dns_packet_read_rr(DnsPacket
*p
, DnsResourceRecord
**ret
, bool *ret_cache_flush
, size_t *start
) {
1601 _cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr
= NULL
;
1602 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*key
= NULL
;
1603 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
;
1612 INIT_REWINDER(rewinder
, p
);
1614 r
= dns_packet_read_key(p
, &key
, &cache_flush
, NULL
);
1618 if (!dns_class_is_valid_rr(key
->class) || !dns_type_is_valid_rr(key
->type
))
1621 rr
= dns_resource_record_new(key
);
1625 r
= dns_packet_read_uint32(p
, &rr
->ttl
, NULL
);
1629 /* RFC 2181, Section 8, suggests to
1630 * treat a TTL with the MSB set as a zero TTL. */
1631 if (rr
->ttl
& UINT32_C(0x80000000))
1634 r
= dns_packet_read_uint16(p
, &rdlength
, NULL
);
1638 if (p
->rindex
+ rdlength
> p
->size
)
1643 switch (rr
->key
->type
) {
1646 r
= dns_packet_read_uint16(p
, &rr
->srv
.priority
, NULL
);
1649 r
= dns_packet_read_uint16(p
, &rr
->srv
.weight
, NULL
);
1652 r
= dns_packet_read_uint16(p
, &rr
->srv
.port
, NULL
);
1655 r
= dns_packet_read_name(p
, &rr
->srv
.name
, true, NULL
);
1660 case DNS_TYPE_CNAME
:
1661 case DNS_TYPE_DNAME
:
1662 r
= dns_packet_read_name(p
, &rr
->ptr
.name
, true, NULL
);
1665 case DNS_TYPE_HINFO
:
1666 r
= dns_packet_read_string(p
, &rr
->hinfo
.cpu
, NULL
);
1670 r
= dns_packet_read_string(p
, &rr
->hinfo
.os
, NULL
);
1673 case DNS_TYPE_SPF
: /* exactly the same as TXT */
1675 if (rdlength
<= 0) {
1677 /* RFC 6763, section 6.1 suggests to treat
1678 * empty TXT RRs as equivalent to a TXT record
1679 * with a single empty string. */
1681 i
= malloc0(offsetof(DnsTxtItem
, data
) + 1); /* for safety reasons we add an extra NUL byte */
1687 DnsTxtItem
*last
= NULL
;
1689 while (p
->rindex
< offset
+ rdlength
) {
1694 r
= dns_packet_read_raw_string(p
, &data
, &sz
, NULL
);
1698 i
= malloc0(offsetof(DnsTxtItem
, data
) + sz
+ 1); /* extra NUL byte at the end */
1702 memcpy(i
->data
, data
, sz
);
1705 LIST_INSERT_AFTER(items
, rr
->txt
.items
, last
, i
);
1714 r
= dns_packet_read_blob(p
, &rr
->a
.in_addr
, sizeof(struct in_addr
), NULL
);
1718 r
= dns_packet_read_blob(p
, &rr
->aaaa
.in6_addr
, sizeof(struct in6_addr
), NULL
);
1722 r
= dns_packet_read_name(p
, &rr
->soa
.mname
, true, NULL
);
1726 r
= dns_packet_read_name(p
, &rr
->soa
.rname
, true, NULL
);
1730 r
= dns_packet_read_uint32(p
, &rr
->soa
.serial
, NULL
);
1734 r
= dns_packet_read_uint32(p
, &rr
->soa
.refresh
, NULL
);
1738 r
= dns_packet_read_uint32(p
, &rr
->soa
.retry
, NULL
);
1742 r
= dns_packet_read_uint32(p
, &rr
->soa
.expire
, NULL
);
1746 r
= dns_packet_read_uint32(p
, &rr
->soa
.minimum
, NULL
);
1750 r
= dns_packet_read_uint16(p
, &rr
->mx
.priority
, NULL
);
1754 r
= dns_packet_read_name(p
, &rr
->mx
.exchange
, true, NULL
);
1757 case DNS_TYPE_LOC
: {
1761 r
= dns_packet_read_uint8(p
, &t
, &pos
);
1766 rr
->loc
.version
= t
;
1768 r
= dns_packet_read_uint8(p
, &rr
->loc
.size
, NULL
);
1772 if (!loc_size_ok(rr
->loc
.size
))
1775 r
= dns_packet_read_uint8(p
, &rr
->loc
.horiz_pre
, NULL
);
1779 if (!loc_size_ok(rr
->loc
.horiz_pre
))
1782 r
= dns_packet_read_uint8(p
, &rr
->loc
.vert_pre
, NULL
);
1786 if (!loc_size_ok(rr
->loc
.vert_pre
))
1789 r
= dns_packet_read_uint32(p
, &rr
->loc
.latitude
, NULL
);
1793 r
= dns_packet_read_uint32(p
, &rr
->loc
.longitude
, NULL
);
1797 r
= dns_packet_read_uint32(p
, &rr
->loc
.altitude
, NULL
);
1803 dns_packet_rewind(p
, pos
);
1804 rr
->unparseable
= true;
1810 r
= dns_packet_read_uint16(p
, &rr
->ds
.key_tag
, NULL
);
1814 r
= dns_packet_read_uint8(p
, &rr
->ds
.algorithm
, NULL
);
1818 r
= dns_packet_read_uint8(p
, &rr
->ds
.digest_type
, NULL
);
1822 r
= dns_packet_read_memdup(p
, rdlength
- 4,
1823 &rr
->ds
.digest
, &rr
->ds
.digest_size
,
1828 if (rr
->ds
.digest_size
<= 0)
1829 /* the accepted size depends on the algorithm, but for now
1830 just ensure that the value is greater than zero */
1835 case DNS_TYPE_SSHFP
:
1836 r
= dns_packet_read_uint8(p
, &rr
->sshfp
.algorithm
, NULL
);
1840 r
= dns_packet_read_uint8(p
, &rr
->sshfp
.fptype
, NULL
);
1844 r
= dns_packet_read_memdup(p
, rdlength
- 2,
1845 &rr
->sshfp
.fingerprint
, &rr
->sshfp
.fingerprint_size
,
1848 if (rr
->sshfp
.fingerprint_size
<= 0)
1849 /* the accepted size depends on the algorithm, but for now
1850 just ensure that the value is greater than zero */
1855 case DNS_TYPE_DNSKEY
:
1856 r
= dns_packet_read_uint16(p
, &rr
->dnskey
.flags
, NULL
);
1860 r
= dns_packet_read_uint8(p
, &rr
->dnskey
.protocol
, NULL
);
1864 r
= dns_packet_read_uint8(p
, &rr
->dnskey
.algorithm
, NULL
);
1868 r
= dns_packet_read_memdup(p
, rdlength
- 4,
1869 &rr
->dnskey
.key
, &rr
->dnskey
.key_size
,
1872 if (rr
->dnskey
.key_size
<= 0)
1873 /* the accepted size depends on the algorithm, but for now
1874 just ensure that the value is greater than zero */
1879 case DNS_TYPE_RRSIG
:
1880 r
= dns_packet_read_uint16(p
, &rr
->rrsig
.type_covered
, NULL
);
1884 r
= dns_packet_read_uint8(p
, &rr
->rrsig
.algorithm
, NULL
);
1888 r
= dns_packet_read_uint8(p
, &rr
->rrsig
.labels
, NULL
);
1892 r
= dns_packet_read_uint32(p
, &rr
->rrsig
.original_ttl
, NULL
);
1896 r
= dns_packet_read_uint32(p
, &rr
->rrsig
.expiration
, NULL
);
1900 r
= dns_packet_read_uint32(p
, &rr
->rrsig
.inception
, NULL
);
1904 r
= dns_packet_read_uint16(p
, &rr
->rrsig
.key_tag
, NULL
);
1908 r
= dns_packet_read_name(p
, &rr
->rrsig
.signer
, false, NULL
);
1912 r
= dns_packet_read_memdup(p
, offset
+ rdlength
- p
->rindex
,
1913 &rr
->rrsig
.signature
, &rr
->rrsig
.signature_size
,
1916 if (rr
->rrsig
.signature_size
<= 0)
1917 /* the accepted size depends on the algorithm, but for now
1918 just ensure that the value is greater than zero */
1923 case DNS_TYPE_NSEC
: {
1926 * RFC6762, section 18.14 explictly states mDNS should use name compression.
1927 * This contradicts RFC3845, section 2.1.1
1930 bool allow_compressed
= p
->protocol
== DNS_PROTOCOL_MDNS
;
1932 r
= dns_packet_read_name(p
, &rr
->nsec
.next_domain_name
, allow_compressed
, NULL
);
1936 r
= dns_packet_read_type_windows(p
, &rr
->nsec
.types
, offset
+ rdlength
- p
->rindex
, NULL
);
1938 /* We accept empty NSEC bitmaps. The bit indicating the presence of the NSEC record itself
1939 * is redundant and in e.g., RFC4956 this fact is used to define a use for NSEC records
1940 * without the NSEC bit set. */
1944 case DNS_TYPE_NSEC3
: {
1947 r
= dns_packet_read_uint8(p
, &rr
->nsec3
.algorithm
, NULL
);
1951 r
= dns_packet_read_uint8(p
, &rr
->nsec3
.flags
, NULL
);
1955 r
= dns_packet_read_uint16(p
, &rr
->nsec3
.iterations
, NULL
);
1959 /* this may be zero */
1960 r
= dns_packet_read_uint8(p
, &size
, NULL
);
1964 r
= dns_packet_read_memdup(p
, size
, &rr
->nsec3
.salt
, &rr
->nsec3
.salt_size
, NULL
);
1968 r
= dns_packet_read_uint8(p
, &size
, NULL
);
1975 r
= dns_packet_read_memdup(p
, size
,
1976 &rr
->nsec3
.next_hashed_name
, &rr
->nsec3
.next_hashed_name_size
,
1981 r
= dns_packet_read_type_windows(p
, &rr
->nsec3
.types
, offset
+ rdlength
- p
->rindex
, NULL
);
1983 /* empty non-terminals can have NSEC3 records, so empty bitmaps are allowed */
1989 r
= dns_packet_read_uint8(p
, &rr
->tlsa
.cert_usage
, NULL
);
1993 r
= dns_packet_read_uint8(p
, &rr
->tlsa
.selector
, NULL
);
1997 r
= dns_packet_read_uint8(p
, &rr
->tlsa
.matching_type
, NULL
);
2001 r
= dns_packet_read_memdup(p
, rdlength
- 3,
2002 &rr
->tlsa
.data
, &rr
->tlsa
.data_size
,
2005 if (rr
->tlsa
.data_size
<= 0)
2006 /* the accepted size depends on the algorithm, but for now
2007 just ensure that the value is greater than zero */
2013 r
= dns_packet_read_uint8(p
, &rr
->caa
.flags
, NULL
);
2017 r
= dns_packet_read_string(p
, &rr
->caa
.tag
, NULL
);
2021 r
= dns_packet_read_memdup(p
,
2022 rdlength
+ offset
- p
->rindex
,
2023 &rr
->caa
.value
, &rr
->caa
.value_size
, NULL
);
2027 case DNS_TYPE_OPT
: /* we only care about the header of OPT for now. */
2028 case DNS_TYPE_OPENPGPKEY
:
2031 r
= dns_packet_read_memdup(p
, rdlength
, &rr
->generic
.data
, &rr
->generic
.data_size
, NULL
);
2037 if (p
->rindex
!= offset
+ rdlength
)
2043 if (ret_cache_flush
)
2044 *ret_cache_flush
= cache_flush
;
2046 *start
= rewinder
.saved_rindex
;
2047 CANCEL_REWINDER(rewinder
);
2052 static bool opt_is_good(DnsResourceRecord
*rr
, bool *rfc6975
) {
2054 bool found_dau_dhu_n3u
= false;
2057 /* Checks whether the specified OPT RR is well-formed and whether it contains RFC6975 data (which is not OK in
2061 assert(rr
->key
->type
== DNS_TYPE_OPT
);
2063 /* Check that the version is 0 */
2064 if (((rr
->ttl
>> 16) & UINT32_C(0xFF)) != 0) {
2066 return true; /* if it's not version 0, it's OK, but we will ignore the OPT field contents */
2070 l
= rr
->opt
.data_size
;
2072 uint16_t option_code
, option_length
;
2074 /* At least four bytes for OPTION-CODE and OPTION-LENGTH are required */
2078 option_code
= unaligned_read_be16(p
);
2079 option_length
= unaligned_read_be16(p
+ 2);
2081 if (l
< option_length
+ 4U)
2084 /* RFC 6975 DAU, DHU or N3U fields found. */
2085 if (IN_SET(option_code
, 5, 6, 7))
2086 found_dau_dhu_n3u
= true;
2088 p
+= option_length
+ 4U;
2089 l
-= option_length
+ 4U;
2092 *rfc6975
= found_dau_dhu_n3u
;
2096 int dns_packet_extract(DnsPacket
*p
) {
2097 _cleanup_(dns_question_unrefp
) DnsQuestion
*question
= NULL
;
2098 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
2099 _cleanup_(rewind_dns_packet
) DnsPacketRewinder rewinder
= {};
2106 INIT_REWINDER(rewinder
, p
);
2107 dns_packet_rewind(p
, DNS_PACKET_HEADER_SIZE
);
2109 n
= DNS_PACKET_QDCOUNT(p
);
2111 question
= dns_question_new(n
);
2115 for (i
= 0; i
< n
; i
++) {
2116 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*key
= NULL
;
2119 r
= dns_packet_read_key(p
, &key
, &cache_flush
, NULL
);
2126 if (!dns_type_is_valid_query(key
->type
))
2129 r
= dns_question_add(question
, key
);
2135 n
= DNS_PACKET_RRCOUNT(p
);
2137 _cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*previous
= NULL
;
2138 bool bad_opt
= false;
2140 answer
= dns_answer_new(n
);
2144 for (i
= 0; i
< n
; i
++) {
2145 _cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr
= NULL
;
2148 r
= dns_packet_read_rr(p
, &rr
, &cache_flush
, NULL
);
2152 /* Try to reduce memory usage a bit */
2154 dns_resource_key_reduce(&rr
->key
, &previous
->key
);
2156 if (rr
->key
->type
== DNS_TYPE_OPT
) {
2159 if (p
->opt
|| bad_opt
) {
2160 /* Multiple OPT RRs? if so, let's ignore all, because there's something wrong
2161 * with the server, and if one is valid we wouldn't know which one. */
2162 log_debug("Multiple OPT RRs detected, ignoring all.");
2167 if (!dns_name_is_root(dns_resource_key_name(rr
->key
))) {
2168 /* If the OPT RR is not owned by the root domain, then it is bad, let's ignore
2170 log_debug("OPT RR is not owned by root domain, ignoring.");
2175 if (i
< DNS_PACKET_ANCOUNT(p
) + DNS_PACKET_NSCOUNT(p
)) {
2176 /* OPT RR is in the wrong section? Some Belkin routers do this. This is a hint
2177 * the EDNS implementation is borked, like the Belkin one is, hence ignore
2179 log_debug("OPT RR in wrong section, ignoring.");
2184 if (!opt_is_good(rr
, &has_rfc6975
)) {
2185 log_debug("Malformed OPT RR, ignoring.");
2190 if (DNS_PACKET_QR(p
)) {
2191 /* Additional checks for responses */
2193 if (!DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(rr
)) {
2194 /* If this is a reply and we don't know the EDNS version then something
2196 log_debug("EDNS version newer that our request, bad server.");
2201 /* If the OPT RR contains RFC6975 algorithm data, then this is indication that
2202 * the server just copied the OPT it got from us (which contained that data)
2203 * back into the reply. If so, then it doesn't properly support EDNS, as
2204 * RFC6975 makes it very clear that the algorithm data should only be contained
2205 * in questions, never in replies. Crappy Belkin routers copy the OPT data for
2206 * example, hence let's detect this so that we downgrade early. */
2207 log_debug("OPT RR contained RFC6975 data, ignoring.");
2213 p
->opt
= dns_resource_record_ref(rr
);
2216 /* According to RFC 4795, section 2.9. only the RRs from the Answer section shall be
2217 * cached. Hence mark only those RRs as cacheable by default, but not the ones from the
2218 * Additional or Authority sections. */
2220 r
= dns_answer_add(answer
, rr
, p
->ifindex
,
2221 (i
< DNS_PACKET_ANCOUNT(p
) ? DNS_ANSWER_CACHEABLE
: 0) |
2222 (p
->protocol
== DNS_PROTOCOL_MDNS
&& !cache_flush
? DNS_ANSWER_SHARED_OWNER
: 0));
2227 /* Remember this RR, so that we potentically can merge it's ->key object with the next RR. Note
2228 * that we only do this if we actually decided to keep the RR around. */
2229 dns_resource_record_unref(previous
);
2230 previous
= dns_resource_record_ref(rr
);
2234 p
->opt
= dns_resource_record_unref(p
->opt
);
2237 p
->question
= question
;
2243 p
->extracted
= true;
2245 /* no CANCEL, always rewind */
2249 int dns_packet_is_reply_for(DnsPacket
*p
, const DnsResourceKey
*key
) {
2255 /* Checks if the specified packet is a reply for the specified
2256 * key and the specified key is the only one in the question
2259 if (DNS_PACKET_QR(p
) != 1)
2262 /* Let's unpack the packet, if that hasn't happened yet. */
2263 r
= dns_packet_extract(p
);
2267 if (p
->question
->n_keys
!= 1)
2270 return dns_resource_key_equal(p
->question
->keys
[0], key
);
2273 static const char* const dns_rcode_table
[_DNS_RCODE_MAX_DEFINED
] = {
2274 [DNS_RCODE_SUCCESS
] = "SUCCESS",
2275 [DNS_RCODE_FORMERR
] = "FORMERR",
2276 [DNS_RCODE_SERVFAIL
] = "SERVFAIL",
2277 [DNS_RCODE_NXDOMAIN
] = "NXDOMAIN",
2278 [DNS_RCODE_NOTIMP
] = "NOTIMP",
2279 [DNS_RCODE_REFUSED
] = "REFUSED",
2280 [DNS_RCODE_YXDOMAIN
] = "YXDOMAIN",
2281 [DNS_RCODE_YXRRSET
] = "YRRSET",
2282 [DNS_RCODE_NXRRSET
] = "NXRRSET",
2283 [DNS_RCODE_NOTAUTH
] = "NOTAUTH",
2284 [DNS_RCODE_NOTZONE
] = "NOTZONE",
2285 [DNS_RCODE_BADVERS
] = "BADVERS",
2286 [DNS_RCODE_BADKEY
] = "BADKEY",
2287 [DNS_RCODE_BADTIME
] = "BADTIME",
2288 [DNS_RCODE_BADMODE
] = "BADMODE",
2289 [DNS_RCODE_BADNAME
] = "BADNAME",
2290 [DNS_RCODE_BADALG
] = "BADALG",
2291 [DNS_RCODE_BADTRUNC
] = "BADTRUNC",
2292 [DNS_RCODE_BADCOOKIE
] = "BADCOOKIE",
2294 DEFINE_STRING_TABLE_LOOKUP(dns_rcode
, int);
2296 static const char* const dns_protocol_table
[_DNS_PROTOCOL_MAX
] = {
2297 [DNS_PROTOCOL_DNS
] = "dns",
2298 [DNS_PROTOCOL_MDNS
] = "mdns",
2299 [DNS_PROTOCOL_LLMNR
] = "llmnr",
2301 DEFINE_STRING_TABLE_LOOKUP(dns_protocol
, DnsProtocol
);