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/*
** Copyright (C) 2006 Olivier DEMBOUR
** $Id: dns.h,v 1.16.4.2 2010/06/01 16:05:05 collignon Exp $
**
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with This program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __DNS_H__
#define __DNS_H__
#include "config.h"
#ifndef _WIN32
#include <unistd.h>
#include <arpa/inet.h>
#else
#include "mywin32.h"
#endif
#include "base64.h"
#define MAX_DNS_LEN 512
#define MAX_EDNS_LEN 4096
#define EDNS_HEADER 11
#define MAX_HOST_NAME_ENCODED 200 /* need space for reply */
#define MAX_HOST_NAME_DECODED DECODED_LEN((MAX_HOST_NAME_ENCODED))
#define ENCODED_LEN(len) (((len) + (((len) / 63) + 1)))
#define DECODED_LEN(len) ( ((len)>0) ? (((len) - (((len) / 63) + 1))) : 0)
/* USE EDNS or std DNS */
#define MAX_ENCODE_DATA(len, dns_size) \
( \
(((len)+RR_HDR_SIZE) > (dns_size - AUTHORITATIVE_SIZE)) ? 0 : \
DECODED_LEN(DECODED_BASE64_SIZE(\
( (dns_size - AUTHORITATIVE_SIZE) - (len) - (RR_HDR_SIZE)) ) \
))
#define MAX_RAW_DATA(len, dns_size) \
( \
(((len)+RR_HDR_SIZE) > (dns_size - AUTHORITATIVE_SIZE)) ? 0 : \
DECODED_BASE64_SIZE(\
( (dns_size - AUTHORITATIVE_SIZE) - (len) - (RR_HDR_SIZE) ) ) \
)
#define AUTHORITATIVE_SIZE 50 /* should be better defined ... */
/* Additional record + Authoritative nameserver */
#define ENCODE_DATA_AVAILABLE(len, query_len, dns_size) (client && (client->control.use_compress)) ? \
((MAX_ENCODE_DATA((len + 2), (dns_size)))) : \
((MAX_ENCODE_DATA((len + query_len), (dns_size))))
#define RAW_DATA_AVAILABLE(len, query_len, dns_size) (client && (client->control.use_compress)) ? \
((MAX_RAW_DATA((len + 2), (dns_size)))) : \
((MAX_RAW_DATA((len + query_len), (dns_size))))
/*
#define ENCODE_DATA_AVAILABLE(len, query_len, dns_size) (client && (client->control.use_compress)) ? \
((MAX_ENCODE_DATA((len) + 2, (dns_size + 1)))) : \
((MAX_ENCODE_DATA((len) + (query_len), (dns_size))))
#define RAW_DATA_AVAILABLE(len, query_len, dns_size) (client && (client->control.use_compress)) ? \
((MAX_RAW_DATA((len) + 2, (dns_size + 1)))) : \
((MAX_RAW_DATA((len) + (query_len), (dns_size))))
*/
#define MAX_QNAME_DATA(domain) (DECODED_BASE64_SIZE(MAX_HOST_NAME_DECODED - strlen(domain) - 1))
/* GCC alignement padding workaround */
#define DNS_HDR_SIZE 12
#define RR_HDR_SIZE 10
#define REQ_HDR_SIZE 4
#define JUMP_DNS_HDR(hdr) ((char *)hdr + DNS_HDR_SIZE)
#define JUMP_RR_HDR(hdr) ((char *)hdr + RR_HDR_SIZE)
#define JUMP_REQ_HDR(hdr) ((char *)hdr + REQ_HDR_SIZE)
#define COMPRESS_FLAG_CHAR 0xC0
#define COMPRESS_FLAG 0xC000
#define GET_DECOMPRESS_OFFSET(offset) ((ntohs(offset)) & ~(COMPRESS_FLAG))
/* Why not */
#define MAX_COMPRESS_DEPTH 10
/* Network order */
#define PUT_16(dst, src) do \
{\
((unsigned char *)(dst))[0] = (uint8_t) ((src ) >> 8) ; \
((unsigned char *)(dst))[1] = (uint8_t) (src) ; \
} while (0)
#define PUT_32(dst, src) do \
{\
((unsigned char *)(dst))[0] = (uint8_t) ((src ) >> 24) ; \
((unsigned char *)(dst))[1] = (uint8_t) ((src ) >> 16) ; \
((unsigned char *)(dst))[2] = (uint8_t) ((src ) >> 8) ; \
((unsigned char *)(dst))[3] = (uint8_t) (src) ; \
} while (0)
/* Host order */
#define GET_16(src) ((((unsigned char *)(src))[0] << 8) | (((unsigned char *)(src))[1]) )
#define GET_32(src) (\
(((unsigned char *)(src))[0] << 24) | \
(((unsigned char *)(src))[1] << 16) | \
(((unsigned char *)(src))[2] << 8) | \
(((unsigned char *)(src))[3] ) \
)
/* FIXME hardcoded '=' is bad ! (check base64_padding ...) */
#define RESOURCE "=resource."
#define AUTH "=auth."
#define CONNECT "=connect."
struct dns_hdr {
uint16_t id;
#ifndef WORDS_BIGENDIAN
uint16_t rd:1, /* recurse demand */
tc:1, /* truncated */
aa:1, /* authorative */
opcode:4,
qr:1,
rcode:4,
z:3,
ra:1; /* recurse available */
#else
uint16_t qr:1,
opcode:4,
aa:1,
tc:1,
rd:1,
ra:1,
z:3,
rcode:4;
#endif
#define RCODE_NO_ERR 0x0
#define RCODE_FORMAT_ERR 0x1
#define RCODE_SRV_FAILURE 0x2
#define RCODE_NAME_ERR 0x3
#define RCODE_NOT_IMPLEMENTED 0x4
#define RCODE_REFUSED 0x3
uint16_t qdcount; /* nb queries */
uint16_t ancount; /* nb answers */
uint16_t nscount; /* authority records */
uint16_t arcount; /* additional records */
} __attribute__((packed));
#define MAX_DNS_ERROR 6
extern const char *dns_error[MAX_DNS_ERROR];
struct req_hdr {
uint16_t qtype; /* TXT */
uint16_t qclass; /* IN | CHAOS */
} __attribute__((packed));
struct rr_hdr {
uint16_t type;
#define TYPE_TXT 16
#define TYPE_KEY 25
uint16_t klass;
#define CLASS_IN 1
uint32_t ttl;
uint16_t rdlength;
} __attribute__((packed));
struct add_record {
uint8_t name;
uint16_t type;
#define TYPE_EDNS 41
uint16_t payload_size;
uint8_t rcode;
uint8_t version;
uint16_t z;
uint16_t length;
} __attribute__((packed));
void dns_simple_decode(char *input, char *output, int max_len);
void dns_simple_decode_strip_dot(char *input, char *output, int max_len);
void dns_encode(char *);
void *jump_end_query(void *, int, int);
void *jump_qname(void *, int);
void *jump_end_answer(void *buffer, int max_len);
void *jump_edns(void *buffer, int max_len);
#endif
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