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/>.
24 #include <netinet/udp.h>
25 #include <netinet/ip.h>
28 #include "sparse-endian.h"
30 #include "in-addr-util.h"
32 typedef struct DnsPacketHeader DnsPacketHeader
;
33 typedef struct DnsPacket DnsPacket
;
35 #include "resolved-dns-rr.h"
36 #include "resolved-dns-question.h"
37 #include "resolved-dns-answer.h"
38 #include "resolved-def.h"
40 typedef enum DnsProtocol
{
45 _DNS_PROTOCOL_INVALID
= -1
48 struct DnsPacketHeader
{
57 #define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader)
58 #define UDP_PACKET_HEADER_SIZE (sizeof(struct iphdr) + sizeof(struct udphdr))
60 /* The various DNS protocols deviate in how large a packet can grow,
61 but the TCP transport has a 16bit size field, hence that appears to
62 be the absolute maximum. */
63 #define DNS_PACKET_SIZE_MAX 0xFFFF
65 /* RFC 1035 say 512 is the maximum, for classic unicast DNS */
66 #define DNS_PACKET_UNICAST_SIZE_MAX 512
68 #define DNS_PACKET_SIZE_START 512
73 size_t size
, allocated
, rindex
;
74 void *_data
; /* don't access directly, use DNS_PACKET_DATA()! */
75 Hashmap
*names
; /* For name compression */
78 DnsQuestion
*question
;
81 /* Packet reception meta data */
84 union in_addr_union sender
, destination
;
85 uint16_t sender_port
, destination_port
;
91 static inline uint8_t* DNS_PACKET_DATA(DnsPacket
*p
) {
98 return ((uint8_t*) p
) + ALIGN(sizeof(DnsPacket
));
101 #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
102 #define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id
103 #define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)
104 #define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)
105 #define DNS_PACKET_AA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 10) & 1)
106 #define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)
107 #define DNS_PACKET_RD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 8) & 1)
108 #define DNS_PACKET_RA(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 7) & 1)
109 #define DNS_PACKET_AD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 5) & 1)
110 #define DNS_PACKET_CD(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 4) & 1)
111 #define DNS_PACKET_RCODE(p) (be16toh(DNS_PACKET_HEADER(p)->flags) & 15)
113 /* LLMNR defines some bits differently */
114 #define DNS_PACKET_LLMNR_C(p) DNS_PACKET_AA(p)
115 #define DNS_PACKET_LLMNR_T(p) DNS_PACKET_RD(p)
117 #define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)
118 #define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)
119 #define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)
120 #define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)
122 #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
123 (((uint16_t) !!qr << 15) | \
124 ((uint16_t) (opcode & 15) << 11) | \
125 ((uint16_t) !!aa << 10) | \
126 ((uint16_t) !!tc << 9) | \
127 ((uint16_t) !!rd << 8) | \
128 ((uint16_t) !!ra << 7) | \
129 ((uint16_t) !!ad << 5) | \
130 ((uint16_t) !!cd << 4) | \
131 ((uint16_t) (rcode & 15)))
133 static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket
*p
) {
135 (unsigned) DNS_PACKET_ANCOUNT(p
) +
136 (unsigned) DNS_PACKET_NSCOUNT(p
) +
137 (unsigned) DNS_PACKET_ARCOUNT(p
);
140 int dns_packet_new(DnsPacket
**p
, DnsProtocol protocol
, size_t mtu
);
141 int dns_packet_new_query(DnsPacket
**p
, DnsProtocol protocol
, size_t mtu
);
143 DnsPacket
*dns_packet_ref(DnsPacket
*p
);
144 DnsPacket
*dns_packet_unref(DnsPacket
*p
);
146 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket
*, dns_packet_unref
);
148 int dns_packet_validate(DnsPacket
*p
);
149 int dns_packet_validate_reply(DnsPacket
*p
);
150 int dns_packet_validate_query(DnsPacket
*p
);
152 int dns_packet_append_blob(DnsPacket
*p
, const void *d
, size_t sz
, size_t *start
);
153 int dns_packet_append_uint8(DnsPacket
*p
, uint8_t v
, size_t *start
);
154 int dns_packet_append_uint16(DnsPacket
*p
, uint16_t v
, size_t *start
);
155 int dns_packet_append_uint32(DnsPacket
*p
, uint32_t v
, size_t *start
);
156 int dns_packet_append_string(DnsPacket
*p
, const char *s
, size_t *start
);
157 int dns_packet_append_label(DnsPacket
*p
, const char *s
, size_t l
, size_t *start
);
158 int dns_packet_append_name(DnsPacket
*p
, const char *name
,
159 bool allow_compression
, size_t *start
);
160 int dns_packet_append_key(DnsPacket
*p
, const DnsResourceKey
*key
, size_t *start
);
161 int dns_packet_append_rr(DnsPacket
*p
, const DnsResourceRecord
*rr
, size_t *start
);
163 int dns_packet_read(DnsPacket
*p
, size_t sz
, const void **ret
, size_t *start
);
164 int dns_packet_read_blob(DnsPacket
*p
, void *d
, size_t sz
, size_t *start
);
165 int dns_packet_read_uint8(DnsPacket
*p
, uint8_t *ret
, size_t *start
);
166 int dns_packet_read_uint16(DnsPacket
*p
, uint16_t *ret
, size_t *start
);
167 int dns_packet_read_uint32(DnsPacket
*p
, uint32_t *ret
, size_t *start
);
168 int dns_packet_read_string(DnsPacket
*p
, char **ret
, size_t *start
);
169 int dns_packet_read_name(DnsPacket
*p
, char **ret
,
170 bool allow_compression
, size_t *start
);
171 int dns_packet_read_key(DnsPacket
*p
, DnsResourceKey
**ret
, size_t *start
);
172 int dns_packet_read_rr(DnsPacket
*p
, DnsResourceRecord
**ret
, size_t *start
);
174 void dns_packet_rewind(DnsPacket
*p
, size_t idx
);
176 int dns_packet_skip_question(DnsPacket
*p
);
177 int dns_packet_extract(DnsPacket
*p
);
180 DNS_RCODE_SUCCESS
= 0,
181 DNS_RCODE_FORMERR
= 1,
182 DNS_RCODE_SERVFAIL
= 2,
183 DNS_RCODE_NXDOMAIN
= 3,
184 DNS_RCODE_NOTIMP
= 4,
185 DNS_RCODE_REFUSED
= 5,
186 DNS_RCODE_YXDOMAIN
= 6,
187 DNS_RCODE_YXRRSET
= 7,
188 DNS_RCODE_NXRRSET
= 8,
189 DNS_RCODE_NOTAUTH
= 9,
190 DNS_RCODE_NOTZONE
= 10,
191 DNS_RCODE_BADVERS
= 16,
192 DNS_RCODE_BADSIG
= 16, /* duplicate value! */
193 DNS_RCODE_BADKEY
= 17,
194 DNS_RCODE_BADTIME
= 18,
195 DNS_RCODE_BADMODE
= 19,
196 DNS_RCODE_BADNAME
= 20,
197 DNS_RCODE_BADALG
= 21,
198 DNS_RCODE_BADTRUNC
= 22,
199 _DNS_RCODE_MAX_DEFINED
202 const char* dns_rcode_to_string(int i
) _const_
;
203 int dns_rcode_from_string(const char *s
) _pure_
;
205 const char* dns_protocol_to_string(DnsProtocol p
) _const_
;
206 DnsProtocol
dns_protocol_from_string(const char *s
) _pure_
;
208 #define LLMNR_MULTICAST_IPV4_ADDRESS ((struct in_addr) { .s_addr = htobe32(224U << 24 | 252U) })
209 #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 } })
211 #define DNSKEY_FLAG_ZONE_KEY (1u << 8)
212 #define DNSKEY_FLAG_SEP (1u << 0)
214 static inline uint16_t dnskey_to_flags(const DnsResourceRecord
*rr
) {
215 return (rr
->dnskey
.zone_key_flag
* DNSKEY_FLAG_ZONE_KEY
|
216 rr
->dnskey
.sep_flag
* DNSKEY_FLAG_SEP
);
219 /* http://tools.ietf.org/html/rfc4034#appendix-A.1 */
221 DNSSEC_ALGORITHM_RSAMD5
= 1,
223 DNSSEC_ALGORITHM_DSA
,
224 DNSSEC_ALGORITHM_ECC
,
225 DNSSEC_ALGORITHM_RSASHA1
,
226 DNSSEC_ALGORITHM_DSA_NSEC3_SHA1
,
227 DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1
,
228 DNSSEC_ALGORITHM_INDIRECT
= 252,
229 DNSSEC_ALGORITHM_PRIVATEDNS
,
230 DNSSEC_ALGORITHM_PRIVATEOID
,
231 _DNSSEC_ALGORITHM_MAX_DEFINED
234 const char* dnssec_algorithm_to_string(int i
) _const_
;
235 int dnssec_algorithm_from_string(const char *s
) _pure_
;
237 static inline uint64_t SD_RESOLVED_FLAGS_MAKE(DnsProtocol protocol
, int family
) {
239 /* Converts a protocol + family into a flags field as used in queries */
241 if (protocol
== DNS_PROTOCOL_DNS
)
242 return SD_RESOLVED_DNS
;
244 if (protocol
== DNS_PROTOCOL_LLMNR
)
245 return family
== AF_INET6
? SD_RESOLVED_LLMNR_IPV6
: SD_RESOLVED_LLMNR_IPV4
;