src/resolve/resolved-dns-packet.h

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 #pragma once
   4
   5 /***
   6   This file is part of systemd.
   7
   8   Copyright 2014 Lennart Poettering
   9
  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.
  14
  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.
  19
  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/>.
  22  ***/
  23
  24 typedef struct DnsPacketHeader DnsPacketHeader;
  25 typedef struct DnsPacket DnsPacket;
  26
  27 #include <inttypes.h>
  28
  29 #include "macro.h"
  30 #include "sparse-endian.h"
  31 #include "hashmap.h"
  32 #include "resolved-dns-rr.h"
  33
  34 struct DnsPacketHeader {
  35         uint16_t id;
  36         be16_t flags;
  37         be16_t qdcount;
  38         be16_t ancount;
  39         be16_t nscount;
  40         be16_t arcount;
  41 };
  42
  43 #define DNS_PACKET_HEADER_SIZE sizeof(DnsPacketHeader)
  44 #define DNS_PACKET_SIZE_START 512
  45
  46 struct DnsPacket {
  47         int n_ref;
  48         size_t size, allocated, rindex;
  49         Hashmap *names; /* For name compression */
  50         void *data;
  51         int ifindex;
  52 };
  53
  54 static inline uint8_t* DNS_PACKET_DATA(DnsPacket *p) {
  55         if (_unlikely_(!p))
  56                 return NULL;
  57
  58         if (p->data)
  59                 return p->data;
  60
  61         return ((uint8_t*) p) + ALIGN(sizeof(DnsPacket));
  62 }
  63
  64 #define DNS_PACKET_HEADER(p) ((DnsPacketHeader*) DNS_PACKET_DATA(p))
  65
  66 int dns_packet_new(DnsPacket **p, size_t mtu);
  67 int dns_packet_new_query(DnsPacket **p, size_t mtu);
  68
  69 DnsPacket *dns_packet_ref(DnsPacket *p);
  70 DnsPacket *dns_packet_unref(DnsPacket *p);
  71
  72 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsPacket*, dns_packet_unref);
  73
  74 int dns_packet_validate(DnsPacket *p);
  75 int dns_packet_validate_reply(DnsPacket *p);
  76
  77 int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start);
  78 int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start);
  79 int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start);
  80 int dns_packet_append_label(DnsPacket *p, const char *s, size_t l, size_t *start);
  81 int dns_packet_append_name(DnsPacket *p, const char *name, size_t *start);
  82 int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start);
  83
  84 int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start);
  85 int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start);
  86 int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start);
  87 int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start);
  88 int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start);
  89 int dns_packet_read_name(DnsPacket *p, char **ret, size_t *start);
  90 int dns_packet_read_key(DnsPacket *p, DnsResourceKey *ret, size_t *start);
  91 int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start);
  92
  93 int dns_packet_skip_question(DnsPacket *p);
  94
  95 #define DNS_PACKET_MAKE_FLAGS(qr, opcode, aa, tc, rd, ra, ad, cd, rcode) \
  96         (((uint16_t) !!qr << 15) |  \
  97          ((uint16_t) (opcode & 15) << 11) | \
  98          ((uint16_t) !!aa << 10) | \
  99          ((uint16_t) !!tc << 9) | \
 100          ((uint16_t) !!rd << 8) | \
 101          ((uint16_t) !!ra << 7) | \
 102          ((uint16_t) !!ad << 5) | \
 103          ((uint16_t) !!cd << 4) | \
 104          ((uint16_t) (rcode & 15)))
 105
 106 #define DNS_PACKET_RCODE(p) (be16toh(DNS_PACKET_HEADER(p)->flags) & 15)
 107
 108 enum {
 109         DNS_RCODE_SUCCESS = 0,
 110         DNS_RCODE_FORMERR = 1,
 111         DNS_RCODE_SERVFAIL = 2,
 112         DNS_RCODE_NXDOMAIN = 3,
 113         DNS_RCODE_NOTIMP = 4,
 114         DNS_RCODE_REFUSED = 5,
 115         DNS_RCODE_YXDOMAIN = 6,
 116         DNS_RCODE_YXRRSET = 7,
 117         DNS_RCODE_NXRRSET = 8,
 118         DNS_RCODE_NOTAUTH = 9,
 119         DNS_RCODE_NOTZONE = 10,
 120         DNS_RCODE_BADVERS = 16,
 121         DNS_RCODE_BADSIG = 16, /* duplicate value! */
 122         DNS_RCODE_BADKEY = 17,
 123         DNS_RCODE_BADTIME = 18,
 124         DNS_RCODE_BADMODE = 19,
 125         DNS_RCODE_BADNAME = 20,
 126         DNS_RCODE_BADALG = 21,
 127         DNS_RCODE_BADTRUNC = 22,
 128         _DNS_RCODE_MAX_DEFINED
 129 };
 130
 131 const char* dns_rcode_to_string(int i) _const_;
 132 int dns_rcode_from_string(const char *s) _pure_;