1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
6 This file is part of systemd.
8 Copyright 2014 Lennart Poettering
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
20 You should have received a copy of the GNU Lesser General Public License
21 along with systemd; If not, see <http://www.gnu.org/licenses/>.
27 #include "sparse-endian.h"
29 #include "in-addr-util.h"
31 typedef struct DnsPacketHeader DnsPacketHeader
;
32 typedef struct DnsPacket DnsPacket
;
34 #include "resolved-dns-rr.h"
35 #include "resolved-dns-question.h"
36 #include "resolved-dns-answer.h"
37 #include "resolved-def.h"
39 typedef enum DnsProtocol
{
44 _DNS_PROTOCOL_INVALID
= -1
47 struct DnsPacketHeader
{
56 #define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader)
58 /* The various DNS protocols deviate in how large a packet can grow,
59 but the TCP transport has a 16bit size field, hence that appears to
60 be the absolute maximum. */
61 #define DNS_PACKET_SIZE_MAX 0xFFFF
63 /* RFC 1035 say 512 is the maximum, for classic unicast DNS */
64 #define DNS_PACKET_UNICAST_SIZE_MAX 512
66 #define DNS_PACKET_SIZE_START 512
71 size_t size
, allocated
, rindex
;
72 void *_data
; /* don't access directly, use DNS_PACKET_DATA()! */
73 Hashmap
*names
; /* For name compression */
76 DnsQuestion
*question
;
79 /* Packet reception meta data */
82 union in_addr_union sender
, destination
;
83 uint16_t sender_port
, destination_port
;
89 static inline uint8_t* DNS_PACKET_DATA(DnsPacket
*p
) {
96 return ((uint8_t*) p
) + ALIGN(sizeof(DnsPacket
));
99 #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
100 #define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id
101 #define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)
102 #define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)
103 #define DNS_PACKET_RCODE(p) (be16toh(DNS_PACKET_HEADER(p)->flags) & 15)
104 #define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)
105 #define DNS_PACKET_C(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 10) & 1)
106 #define DNS_PACKET_T(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 8) & 1)
107 #define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)
108 #define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)
109 #define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)
110 #define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)
112 #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
113 (((uint16_t) !!qr << 15) | \
114 ((uint16_t) (opcode & 15) << 11) | \
115 ((uint16_t) !!aa << 10) | \
116 ((uint16_t) !!tc << 9) | \
117 ((uint16_t) !!rd << 8) | \
118 ((uint16_t) !!ra << 7) | \
119 ((uint16_t) !!ad << 5) | \
120 ((uint16_t) !!cd << 4) | \
121 ((uint16_t) (rcode & 15)))
123 static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket
*p
) {
125 (unsigned) DNS_PACKET_ANCOUNT(p
) +
126 (unsigned) DNS_PACKET_NSCOUNT(p
) +
127 (unsigned) DNS_PACKET_ARCOUNT(p
);
130 int dns_packet_new(DnsPacket
**p
, DnsProtocol protocol
, size_t mtu
);
131 int dns_packet_new_query(DnsPacket
**p
, DnsProtocol protocol
, size_t mtu
);
133 DnsPacket
*dns_packet_ref(DnsPacket
*p
);
134 DnsPacket
*dns_packet_unref(DnsPacket
*p
);
136 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket
*, dns_packet_unref
);
138 int dns_packet_validate(DnsPacket
*p
);
139 int dns_packet_validate_reply(DnsPacket
*p
);
140 int dns_packet_validate_query(DnsPacket
*p
);
142 int dns_packet_append_blob(DnsPacket
*p
, const void *d
, size_t sz
, size_t *start
);
143 int dns_packet_append_uint8(DnsPacket
*p
, uint8_t v
, size_t *start
);
144 int dns_packet_append_uint16(DnsPacket
*p
, uint16_t v
, size_t *start
);
145 int dns_packet_append_uint32(DnsPacket
*p
, uint32_t v
, size_t *start
);
146 int dns_packet_append_string(DnsPacket
*p
, const char *s
, size_t *start
);
147 int dns_packet_append_label(DnsPacket
*p
, const char *s
, size_t l
, size_t *start
);
148 int dns_packet_append_name(DnsPacket
*p
, const char *name
,
149 bool allow_compression
, size_t *start
);
150 int dns_packet_append_key(DnsPacket
*p
, const DnsResourceKey
*key
, size_t *start
);
151 int dns_packet_append_rr(DnsPacket
*p
, const DnsResourceRecord
*rr
, size_t *start
);
153 int dns_packet_read(DnsPacket
*p
, size_t sz
, const void **ret
, size_t *start
);
154 int dns_packet_read_blob(DnsPacket
*p
, void *d
, size_t sz
, size_t *start
);
155 int dns_packet_read_uint8(DnsPacket
*p
, uint8_t *ret
, size_t *start
);
156 int dns_packet_read_uint16(DnsPacket
*p
, uint16_t *ret
, size_t *start
);
157 int dns_packet_read_uint32(DnsPacket
*p
, uint32_t *ret
, size_t *start
);
158 int dns_packet_read_string(DnsPacket
*p
, char **ret
, size_t *start
);
159 int dns_packet_read_name(DnsPacket
*p
, char **ret
,
160 bool allow_compression
, size_t *start
);
161 int dns_packet_read_key(DnsPacket
*p
, DnsResourceKey
**ret
, size_t *start
);
162 int dns_packet_read_rr(DnsPacket
*p
, DnsResourceRecord
**ret
, size_t *start
);
164 void dns_packet_rewind(DnsPacket
*p
, size_t idx
);
166 int dns_packet_skip_question(DnsPacket
*p
);
167 int dns_packet_extract(DnsPacket
*p
);
170 DNS_RCODE_SUCCESS
= 0,
171 DNS_RCODE_FORMERR
= 1,
172 DNS_RCODE_SERVFAIL
= 2,
173 DNS_RCODE_NXDOMAIN
= 3,
174 DNS_RCODE_NOTIMP
= 4,
175 DNS_RCODE_REFUSED
= 5,
176 DNS_RCODE_YXDOMAIN
= 6,
177 DNS_RCODE_YXRRSET
= 7,
178 DNS_RCODE_NXRRSET
= 8,
179 DNS_RCODE_NOTAUTH
= 9,
180 DNS_RCODE_NOTZONE
= 10,
181 DNS_RCODE_BADVERS
= 16,
182 DNS_RCODE_BADSIG
= 16, /* duplicate value! */
183 DNS_RCODE_BADKEY
= 17,
184 DNS_RCODE_BADTIME
= 18,
185 DNS_RCODE_BADMODE
= 19,
186 DNS_RCODE_BADNAME
= 20,
187 DNS_RCODE_BADALG
= 21,
188 DNS_RCODE_BADTRUNC
= 22,
189 _DNS_RCODE_MAX_DEFINED
192 const char* dns_rcode_to_string(int i
) _const_
;
193 int dns_rcode_from_string(const char *s
) _pure_
;
195 const char* dns_protocol_to_string(DnsProtocol p
) _const_
;
196 DnsProtocol
dns_protocol_from_string(const char *s
) _pure_
;
198 #define LLMNR_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 252U) })
199 #define LLMNR_MULTICAST_IPV6_ADDRESS ((struct in6_addr) { .s6_addr = { 0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x03 } })
201 #define DNSKEY_FLAG_ZONE_KEY (1u << 8)
202 #define DNSKEY_FLAG_SEP (1u << 0)
204 static inline uint16_t dnskey_to_flags(const DnsResourceRecord
*rr
) {
205 return (rr
->dnskey
.zone_key_flag
* DNSKEY_FLAG_ZONE_KEY
|
206 rr
->dnskey
.sep_flag
* DNSKEY_FLAG_SEP
);
209 /* http://tools.ietf.org/html/rfc4034#appendix-A.1 */
211 DNSSEC_ALGORITHM_RSAMD5
= 1,
213 DNSSEC_ALGORITHM_DSA
,
214 DNSSEC_ALGORITHM_ECC
,
215 DNSSEC_ALGORITHM_RSASHA1
,
216 DNSSEC_ALGORITHM_INDIRECT
= 252,
217 DNSSEC_ALGORITHM_PRIVATEDNS
,
218 DNSSEC_ALGORITHM_PRIVATEOID
,
219 _DNSSEC_ALGORITHM_MAX_DEFINED
222 const char* dnssec_algorithm_to_string(int i
) _const_
;
223 int dnssec_algorithm_from_string(const char *s
) _pure_
;
225 static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol
, int family
) {
227 /* Converts a protocol + family into a flags field as used in queries */
229 if (protocol
== DNS_PROTOCOL_DNS
)
230 return SD_RESOLVED_DNS
;
232 if (protocol
== DNS_PROTOCOL_LLMNR
)
233 return family
== AF_INET6
? SD_RESOLVED_LLMNR_IPV6
: SD_RESOLVED_LLMNR_IPV4
;