dns.h

   1 /*
   2  * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #ifndef _DNS_H__
  15 #define _DNS_H__
  16
  17 #define FLAG_RESPONSE           0x8000
  18 #define FLAG_AUTHORATIVE        0x0400
  19
  20 #define TYPE_A                  0x0001
  21 #define TYPE_PTR                0x000C
  22 #define TYPE_TXT                0x0010
  23 #define TYPE_AAAA               0x001c
  24 #define TYPE_SRV                0x0021
  25 #define TYPE_ANY                0x00ff
  26
  27 #define IS_COMPRESSED(x)        ((x & 0xc0) == 0xc0)
  28
  29 #define MCAST_ADDR              "224.0.0.251"
  30 #define MCAST_PORT              5353
  31
  32 #define CLASS_FLUSH             0x8000
  33 #define CLASS_IN                0x0001
  34
  35 #define MAX_NAME_LEN            8096
  36 #define MAX_DATA_LEN            8096
  37
  38 #define C_DNS_SD                "_services._dns-sd._udp.local"
  39
  40 struct dns_header {
  41         uint16_t id;
  42         uint16_t flags;
  43         uint16_t questions;
  44         uint16_t answers;
  45         uint16_t authority;
  46         uint16_t additional;
  47 };
  48
  49 struct dns_srv_data {
  50         uint16_t priority;
  51         uint16_t weight;
  52         uint16_t port;
  53 } __attribute__((packed, aligned(2)));
  54
  55 struct dns_answer {
  56         uint16_t type;
  57         uint16_t class;
  58         uint32_t ttl;
  59         uint16_t rdlength;
  60 } __attribute__((packed, aligned(2)));
  61
  62 struct dns_question {
  63         uint16_t type;
  64         uint16_t class;
  65 } __attribute__((packed, aligned(2)));
  66
  67 struct interface;
  68
  69 extern char rdata_buffer[MAX_DATA_LEN + 1];
  70
  71 extern void dns_send_question(struct interface *iface, const char *question, int type);
  72 extern void dns_init_answer(void);
  73 extern void dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength);
  74 extern void dns_send_answer(struct uloop_fd *u, const char *answer);
  75 extern char* dns_consume_name(const uint8_t *base, int blen, uint8_t **data, int *len);
  76 extern struct dns_answer* dns_consume_answer(uint8_t **data, int *len);
  77 extern struct dns_question* dns_consume_question(uint8_t **data, int *len);
  78 extern struct dns_header* dns_consume_header(uint8_t **data, int *len);
  79 extern const char* dns_type_string(uint16_t type);
  80
  81 #endif