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/>.
26 #include "sparse-endian.h"
28 #include "in-addr-util.h"
30 typedef struct DnsPacketHeader DnsPacketHeader
;
31 typedef struct DnsPacket DnsPacket
;
33 #include "resolved-dns-rr.h"
34 #include "resolved-dns-question.h"
35 #include "resolved-dns-answer.h"
36 #include "resolved-def.h"
38 typedef enum DnsProtocol
{
43 _DNS_PROTOCOL_INVALID
= -1
46 struct DnsPacketHeader
{
55 #define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader)
57 /* The various DNS protocols deviate in how large a packet can grow,
58 but the TCP transport has a 16bit size field, hence that appears to
59 be the absolute maximum. */
60 #define DNS_PACKET_SIZE_MAX 0xFFFF
62 /* RFC 1035 say 512 is the maximum, for classic unicast DNS */
63 #define DNS_PACKET_UNICAST_SIZE_MAX 512
65 #define DNS_PACKET_SIZE_START 512
70 size_t size
, allocated
, rindex
;
71 void *_data
; /* don't access directly, use DNS_PACKET_DATA()! */
72 Hashmap
*names
; /* For name compression */
75 DnsQuestion
*question
;
78 /* Packet reception meta data */
81 union in_addr_union sender
, destination
;
82 uint16_t sender_port
, destination_port
;
88 static inline uint8_t* DNS_PACKET_DATA(DnsPacket
*p
) {
95 return ((uint8_t*) p
) + ALIGN(sizeof(DnsPacket
));
98 #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
99 #define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id
100 #define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)
101 #define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)
102 #define DNS_PACKET_AA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 10) & 1)
103 #define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)
104 #define DNS_PACKET_RD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 8) & 1)
105 #define DNS_PACKET_RA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 7) & 1)
106 #define DNS_PACKET_AD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 5) & 1)
107 #define DNS_PACKET_CD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 4) & 1)
108 #define DNS_PACKET_RCODE(p) (be16toh(DNS_PACKET_HEADER(p)->flags) & 15)
110 /* LLMNR defines some bits differently */
111 #define DNS_PACKET_LLMNR_C(p) DNS_PACKET_AA(p)
112 #define DNS_PACKET_LLMNR_T(p) DNS_PACKET_RD(p)
114 #define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)
115 #define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)
116 #define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)
117 #define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)
119 #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
120 (((uint16_t) !!qr << 15) | \
121 ((uint16_t) (opcode & 15) << 11) | \
122 ((uint16_t) !!aa << 10) | \
123 ((uint16_t) !!tc << 9) | \
124 ((uint16_t) !!rd << 8) | \
125 ((uint16_t) !!ra << 7) | \
126 ((uint16_t) !!ad << 5) | \
127 ((uint16_t) !!cd << 4) | \
128 ((uint16_t) (rcode & 15)))
130 static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket
*p
) {
132 (unsigned) DNS_PACKET_ANCOUNT(p
) +
133 (unsigned) DNS_PACKET_NSCOUNT(p
) +
134 (unsigned) DNS_PACKET_ARCOUNT(p
);
137 int dns_packet_new(DnsPacket
**p
, DnsProtocol protocol
, size_t mtu
);
138 int dns_packet_new_query(DnsPacket
**p
, DnsProtocol protocol
, size_t mtu
);
140 DnsPacket
*dns_packet_ref(DnsPacket
*p
);
141 DnsPacket
*dns_packet_unref(DnsPacket
*p
);
143 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket
*, dns_packet_unref
);
145 int dns_packet_validate(DnsPacket
*p
);
146 int dns_packet_validate_reply(DnsPacket
*p
);
147 int dns_packet_validate_query(DnsPacket
*p
);
149 int dns_packet_append_blob(DnsPacket
*p
, const void *d
, size_t sz
, size_t *start
);
150 int dns_packet_append_uint8(DnsPacket
*p
, uint8_t v
, size_t *start
);
151 int dns_packet_append_uint16(DnsPacket
*p
, uint16_t v
, size_t *start
);
152 int dns_packet_append_uint32(DnsPacket
*p
, uint32_t v
, size_t *start
);
153 int dns_packet_append_string(DnsPacket
*p
, const char *s
, size_t *start
);
154 int dns_packet_append_label(DnsPacket
*p
, const char *s
, size_t l
, size_t *start
);
155 int dns_packet_append_name(DnsPacket
*p
, const char *name
,
156 bool allow_compression
, size_t *start
);
157 int dns_packet_append_key(DnsPacket
*p
, const DnsResourceKey
*key
, size_t *start
);
158 int dns_packet_append_rr(DnsPacket
*p
, const DnsResourceRecord
*rr
, size_t *start
);
160 int dns_packet_read(DnsPacket
*p
, size_t sz
, const void **ret
, size_t *start
);
161 int dns_packet_read_blob(DnsPacket
*p
, void *d
, size_t sz
, size_t *start
);
162 int dns_packet_read_uint8(DnsPacket
*p
, uint8_t *ret
, size_t *start
);
163 int dns_packet_read_uint16(DnsPacket
*p
, uint16_t *ret
, size_t *start
);
164 int dns_packet_read_uint32(DnsPacket
*p
, uint32_t *ret
, size_t *start
);
165 int dns_packet_read_string(DnsPacket
*p
, char **ret
, size_t *start
);
166 int dns_packet_read_name(DnsPacket
*p
, char **ret
,
167 bool allow_compression
, size_t *start
);
168 int dns_packet_read_key(DnsPacket
*p
, DnsResourceKey
**ret
, size_t *start
);
169 int dns_packet_read_rr(DnsPacket
*p
, DnsResourceRecord
**ret
, size_t *start
);
171 void dns_packet_rewind(DnsPacket
*p
, size_t idx
);
173 int dns_packet_skip_question(DnsPacket
*p
);
174 int dns_packet_extract(DnsPacket
*p
);
177 DNS_RCODE_SUCCESS
= 0,
178 DNS_RCODE_FORMERR
= 1,
179 DNS_RCODE_SERVFAIL
= 2,
180 DNS_RCODE_NXDOMAIN
= 3,
181 DNS_RCODE_NOTIMP
= 4,
182 DNS_RCODE_REFUSED
= 5,
183 DNS_RCODE_YXDOMAIN
= 6,
184 DNS_RCODE_YXRRSET
= 7,
185 DNS_RCODE_NXRRSET
= 8,
186 DNS_RCODE_NOTAUTH
= 9,
187 DNS_RCODE_NOTZONE
= 10,
188 DNS_RCODE_BADVERS
= 16,
189 DNS_RCODE_BADSIG
= 16, /* duplicate value! */
190 DNS_RCODE_BADKEY
= 17,
191 DNS_RCODE_BADTIME
= 18,
192 DNS_RCODE_BADMODE
= 19,
193 DNS_RCODE_BADNAME
= 20,
194 DNS_RCODE_BADALG
= 21,
195 DNS_RCODE_BADTRUNC
= 22,
196 _DNS_RCODE_MAX_DEFINED
199 const char* dns_rcode_to_string(int i
) _const_
;
200 int dns_rcode_from_string(const char *s
) _pure_
;
202 const char* dns_protocol_to_string(DnsProtocol p
) _const_
;
203 DnsProtocol
dns_protocol_from_string(const char *s
) _pure_
;
205 #define LLMNR_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 252U) })
206 #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 } })
208 #define DNSKEY_FLAG_ZONE_KEY (1u << 8)
209 #define DNSKEY_FLAG_SEP (1u << 0)
211 static inline uint16_t dnskey_to_flags(const DnsResourceRecord
*rr
) {
212 return (rr
->dnskey
.zone_key_flag
* DNSKEY_FLAG_ZONE_KEY
|
213 rr
->dnskey
.sep_flag
* DNSKEY_FLAG_SEP
);
216 /* http://tools.ietf.org/html/rfc4034#appendix-A.1 */
218 DNSSEC_ALGORITHM_RSAMD5
= 1,
220 DNSSEC_ALGORITHM_DSA
,
221 DNSSEC_ALGORITHM_ECC
,
222 DNSSEC_ALGORITHM_RSASHA1
,
223 DNSSEC_ALGORITHM_INDIRECT
= 252,
224 DNSSEC_ALGORITHM_PRIVATEDNS
,
225 DNSSEC_ALGORITHM_PRIVATEOID
,
226 _DNSSEC_ALGORITHM_MAX_DEFINED
229 const char* dnssec_algorithm_to_string(int i
) _const_
;
230 int dnssec_algorithm_from_string(const char *s
) _pure_
;
232 static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol
, int family
) {
234 /* Converts a protocol + family into a flags field as used in queries */
236 if (protocol
== DNS_PROTOCOL_DNS
)
237 return SD_RESOLVED_DNS
;
239 if (protocol
== DNS_PROTOCOL_LLMNR
)
240 return family
== AF_INET6
? SD_RESOLVED_LLMNR_IPV6
: SD_RESOLVED_LLMNR_IPV4
;