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 */
63 static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {
70 return ((uint8_t*) p) + ALIGN(sizeof(DnsPacket));
73 #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
74 #define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id
75 #define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)
76 #define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)
77 #define DNS_PACKET_RCODE(p) (be16toh(DNS_PACKET_HEADER(p)->flags) & 15)
78 #define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)
79 #define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)
80 #define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)
81 #define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)
82 #define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)
84 #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
85 (((uint16_t) !!qr << 15) | \
86 ((uint16_t) (opcode & 15) << 11) | \
87 ((uint16_t) !!aa << 10) | \
88 ((uint16_t) !!tc << 9) | \
89 ((uint16_t) !!rd << 8) | \
90 ((uint16_t) !!ra << 7) | \
91 ((uint16_t) !!ad << 5) | \
92 ((uint16_t) !!cd << 4) | \
93 ((uint16_t) (rcode & 15)))
96 int dns_packet_new(DnsPacket **p, size_t mtu);
97 int dns_packet_new_query(DnsPacket **p, size_t mtu);
99 DnsPacket *dns_packet_ref(DnsPacket *p);
100 DnsPacket *dns_packet_unref(DnsPacket *p);
102 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket*, dns_packet_unref);
104 int dns_packet_validate(DnsPacket *p);
105 int dns_packet_validate_reply(DnsPacket *p);
107 int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start);
108 int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start);
109 int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start);
110 int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, size_t *start);
111 int dns_packet_append_name(DnsPacket *p, const char *name, size_t *start);
112 int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start);
114 int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start);
115 int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start);
116 int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start);
117 int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start);
118 int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start);
119 int dns_packet_read_name(DnsPacket *p, char **ret, size_t *start);
120 int dns_packet_read_key(DnsPacket *p, DnsResourceKey *ret, size_t *start);
121 int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start);
123 void dns_packet_rewind(DnsPacket *p, size_t idx);
125 int dns_packet_skip_question(DnsPacket *p);
128 DNS_RCODE_SUCCESS = 0,
129 DNS_RCODE_FORMERR = 1,
130 DNS_RCODE_SERVFAIL = 2,
131 DNS_RCODE_NXDOMAIN = 3,
132 DNS_RCODE_NOTIMP = 4,
133 DNS_RCODE_REFUSED = 5,
134 DNS_RCODE_YXDOMAIN = 6,
135 DNS_RCODE_YXRRSET = 7,
136 DNS_RCODE_NXRRSET = 8,
137 DNS_RCODE_NOTAUTH = 9,
138 DNS_RCODE_NOTZONE = 10,
139 DNS_RCODE_BADVERS = 16,
140 DNS_RCODE_BADSIG = 16, /* duplicate value! */
141 DNS_RCODE_BADKEY = 17,
142 DNS_RCODE_BADTIME = 18,
143 DNS_RCODE_BADMODE = 19,
144 DNS_RCODE_BADNAME = 20,
145 DNS_RCODE_BADALG = 21,
146 DNS_RCODE_BADTRUNC = 22,
147 _DNS_RCODE_MAX_DEFINED
150 const char* dns_rcode_to_string(int i) _const_;
151 int dns_rcode_from_string(const char *s) _pure_;