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
48 #define DNS_PACKET_SIZE_MAX 0xFFFF
49 #define DNS_PACKET_SIZE_START 512
54 size_t size, allocated, rindex;
55 Hashmap *names; /* For name compression */
59 static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {
66 return ((uint8_t*) p) + ALIGN(sizeof(DnsPacket));
69 #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
70 #define DNS_PACKET_ID(p) DNS_PACKET_HEADER(p)->id
71 #define DNS_PACKET_QR(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 15) & 1)
72 #define DNS_PACKET_OPCODE(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 11) & 15)
73 #define DNS_PACKET_RCODE(p) (be16toh(DNS_PACKET_HEADER(p)->flags) & 15)
74 #define DNS_PACKET_TC(p) ((be16toh(DNS_PACKET_HEADER(p)->flags) >> 9) & 1)
75 #define DNS_PACKET_QDCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->qdcount)
76 #define DNS_PACKET_ANCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->ancount)
77 #define DNS_PACKET_NSCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->nscount)
78 #define DNS_PACKET_ARCOUNT(p) be16toh(DNS_PACKET_HEADER(p)->arcount)
80 #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
81 (((uint16_t) !!qr << 15) | \
82 ((uint16_t) (opcode & 15) << 11) | \
83 ((uint16_t) !!aa << 10) | \
84 ((uint16_t) !!tc << 9) | \
85 ((uint16_t) !!rd << 8) | \
86 ((uint16_t) !!ra << 7) | \
87 ((uint16_t) !!ad << 5) | \
88 ((uint16_t) !!cd << 4) | \
89 ((uint16_t) (rcode & 15)))
92 int dns_packet_new(DnsPacket **p, size_t mtu);
93 int dns_packet_new_query(DnsPacket **p, size_t mtu);
95 DnsPacket *dns_packet_ref(DnsPacket *p);
96 DnsPacket *dns_packet_unref(DnsPacket *p);
98 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket*, dns_packet_unref);
100 int dns_packet_validate(DnsPacket *p);
101 int dns_packet_validate_reply(DnsPacket *p);
103 int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start);
104 int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start);
105 int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start);
106 int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, size_t *start);
107 int dns_packet_append_name(DnsPacket *p, const char *name, size_t *start);
108 int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start);
110 int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start);
111 int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start);
112 int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start);
113 int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start);
114 int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start);
115 int dns_packet_read_name(DnsPacket *p, char **ret, size_t *start);
116 int dns_packet_read_key(DnsPacket *p, DnsResourceKey *ret, size_t *start);
117 int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start);
119 void dns_packet_rewind(DnsPacket *p, size_t idx);
121 int dns_packet_skip_question(DnsPacket *p);
124 DNS_RCODE_SUCCESS = 0,
125 DNS_RCODE_FORMERR = 1,
126 DNS_RCODE_SERVFAIL = 2,
127 DNS_RCODE_NXDOMAIN = 3,
128 DNS_RCODE_NOTIMP = 4,
129 DNS_RCODE_REFUSED = 5,
130 DNS_RCODE_YXDOMAIN = 6,
131 DNS_RCODE_YXRRSET = 7,
132 DNS_RCODE_NXRRSET = 8,
133 DNS_RCODE_NOTAUTH = 9,
134 DNS_RCODE_NOTZONE = 10,
135 DNS_RCODE_BADVERS = 16,
136 DNS_RCODE_BADSIG = 16, /* duplicate value! */
137 DNS_RCODE_BADKEY = 17,
138 DNS_RCODE_BADTIME = 18,
139 DNS_RCODE_BADMODE = 19,
140 DNS_RCODE_BADNAME = 20,
141 DNS_RCODE_BADALG = 21,
142 DNS_RCODE_BADTRUNC = 22,
143 _DNS_RCODE_MAX_DEFINED
146 const char* dns_rcode_to_string(int i) _const_;
147 int dns_rcode_from_string(const char *s) _pure_;