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 typedef struct DnsPacketHeader DnsPacketHeader;
25 typedef struct DnsPacket DnsPacket;
30 #include "sparse-endian.h"
32 #include "resolved-dns-rr.h"
34 struct DnsPacketHeader {
43 #define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader)
45 /* The various DNS protocols deviate in how large a packet can grow,
46 but the TCP transport has a 16bit size field, hence that appears to
47 be the absolute maximum. */
48 #define DNS_PACKET_SIZE_MAX 0xFFFF
50 /* RFC 1035 say 512 is the maximum, for classic unicast DNS */
51 #define DNS_PACKET_UNICAST_SIZE_MAX 512
53 #define DNS_PACKET_SIZE_START 512
58 size_t size, allocated, rindex;
59 Hashmap *names; /* For name compression */
60 DnsResourceRecord **rrs;
64 static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {
71 return ((uint8_t*) p) + ALIGN(sizeof(DnsPacket));
74 #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
75 #define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id
76 #define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)
77 #define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)
78 #define DNS_PACKET_RCODE(p) (be16toh(DNS_PACKET_HEADER(p)->flags) & 15)
79 #define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)
80 #define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)
81 #define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)
82 #define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)
83 #define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)
85 #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
86 (((uint16_t) !!qr << 15) | \
87 ((uint16_t) (opcode & 15) << 11) | \
88 ((uint16_t) !!aa << 10) | \
89 ((uint16_t) !!tc << 9) | \
90 ((uint16_t) !!rd << 8) | \
91 ((uint16_t) !!ra << 7) | \
92 ((uint16_t) !!ad << 5) | \
93 ((uint16_t) !!cd << 4) | \
94 ((uint16_t) (rcode & 15)))
96 static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket *p) {
98 (unsigned) DNS_PACKET_ANCOUNT(p) +
99 (unsigned) DNS_PACKET_NSCOUNT(p) +
100 (unsigned) DNS_PACKET_ARCOUNT(p);
103 int dns_packet_new(DnsPacket **p, size_t mtu);
104 int dns_packet_new_query(DnsPacket **p, size_t mtu);
106 DnsPacket *dns_packet_ref(DnsPacket *p);
107 DnsPacket *dns_packet_unref(DnsPacket *p);
109 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket*, dns_packet_unref);
111 int dns_packet_validate(DnsPacket *p);
112 int dns_packet_validate_reply(DnsPacket *p);
114 int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start);
115 int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start);
116 int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start);
117 int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, size_t *start);
118 int dns_packet_append_name(DnsPacket *p, const char *name, size_t *start);
119 int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start);
121 int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start);
122 int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start);
123 int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start);
124 int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start);
125 int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start);
126 int dns_packet_read_name(DnsPacket *p, char **ret, size_t *start);
127 int dns_packet_read_key(DnsPacket *p, DnsResourceKey *ret, size_t *start);
128 int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start);
130 void dns_packet_rewind(DnsPacket *p, size_t idx);
132 int dns_packet_skip_question(DnsPacket *p);
133 int dns_packet_extract_rrs(DnsPacket *p);
136 DNS_RCODE_SUCCESS = 0,
137 DNS_RCODE_FORMERR = 1,
138 DNS_RCODE_SERVFAIL = 2,
139 DNS_RCODE_NXDOMAIN = 3,
140 DNS_RCODE_NOTIMP = 4,
141 DNS_RCODE_REFUSED = 5,
142 DNS_RCODE_YXDOMAIN = 6,
143 DNS_RCODE_YXRRSET = 7,
144 DNS_RCODE_NXRRSET = 8,
145 DNS_RCODE_NOTAUTH = 9,
146 DNS_RCODE_NOTZONE = 10,
147 DNS_RCODE_BADVERS = 16,
148 DNS_RCODE_BADSIG = 16, /* duplicate value! */
149 DNS_RCODE_BADKEY = 17,
150 DNS_RCODE_BADTIME = 18,
151 DNS_RCODE_BADMODE = 19,
152 DNS_RCODE_BADNAME = 20,
153 DNS_RCODE_BADALG = 21,
154 DNS_RCODE_BADTRUNC = 22,
155 _DNS_RCODE_MAX_DEFINED
158 const char* dns_rcode_to_string(int i) _const_;
159 int dns_rcode_from_string(const char *s) _pure_;