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 #include <stdint.h>
  18 #include <arpa/inet.h>
  19
  20 #define FLAG_RESPONSE           0x8000
  21 #define FLAG_AUTHORATIVE        0x0400
  22
  23 #define TYPE_A                  0x0001
  24 #define TYPE_PTR                0x000C
  25 #define TYPE_TXT                0x0010
  26 #define TYPE_AAAA               0x001c
  27 #define TYPE_SRV                0x0021
  28 #define TYPE_ANY                0x00ff
  29
  30 #define IS_COMPRESSED(x)        ((x & 0xc0) == 0xc0)
  31
  32 #define MCAST_ADDR              "224.0.0.251"
  33 #define MCAST_ADDR6             "ff02::fb"
  34 #define MCAST_PORT              5353
  35
  36 #define CLASS_UNICAST           0x8000
  37 #define CLASS_IN                0x0001
  38
  39 #define MAX_NAME_LEN            8096
  40 #define MAX_DATA_LEN            8096
  41
  42 #define C_DNS_SD                "_services._dns-sd._udp.local"
  43
  44 struct dns_header {
  45         uint16_t id;
  46         uint16_t flags;
  47         uint16_t questions;
  48         uint16_t answers;
  49         uint16_t authority;
  50         uint16_t additional;
  51 };
  52
  53 struct dns_srv_data {
  54         uint16_t priority;
  55         uint16_t weight;
  56         uint16_t port;
  57 } __attribute__((packed, aligned(2)));
  58
  59 struct dns_answer {
  60         uint16_t type;
  61         uint16_t class;
  62         uint32_t ttl;
  63         uint16_t rdlength;
  64 } __attribute__((packed, aligned(2)));
  65
  66 struct dns_question {
  67         uint16_t type;
  68         uint16_t class;
  69 } __attribute__((packed, aligned(2)));
  70
  71 struct interface;
  72 extern int cfg_proto;
  73
  74 void dns_send_question(struct interface *iface, const char *question, int type, int unicast);
  75 void dns_init_answer(void);
  76 void dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength, int ttl);
  77 void dns_send_answer(struct interface *iface, const char *answer);
  78 const char* dns_type_string(uint16_t type);
  79 void dns_handle_packet(struct interface *iface, struct sockaddr *s, uint16_t port, uint8_t *buf, int len);
  80
  81 #endif