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/* Copyright (c) 2014, Vsevolod Stakhov
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef DNS_PRIVATE_H_
#define DNS_PRIVATE_H_
#include "uthash.h"
#include "utlist.h"
#include "rdns.h"
#include "upstream.h"
#include "ref.h"
static const int dns_port = 53;
static const int default_io_cnt = 8;
#define UDP_PACKET_SIZE 4096
#define DNS_COMPRESSION_BITS 0xC0
#define DNS_D_MAXLABEL 63 /* + 1 '\0' */
#define DNS_D_MAXNAME 255 /* + 1 '\0' */
#define RESOLV_CONF "/etc/resolv.conf"
/**
* Represents DNS server
*/
struct rdns_server {
char *name;
unsigned int port;
unsigned int io_cnt;
struct rdns_io_channel **io_channels;
void *ups_elt;
upstream_entry_t up;
};
struct rdns_request {
struct rdns_resolver *resolver;
struct rdns_async_context *async;
struct rdns_io_channel *io;
struct rdns_reply *reply;
enum rdns_request_type type;
double timeout;
unsigned int retransmits;
int id;
struct rdns_request_name *requested_names;
unsigned int qcount;
enum {
RDNS_REQUEST_NEW = 0,
RDNS_REQUEST_REGISTERED = 1,
RDNS_REQUEST_SENT,
RDNS_REQUEST_REPLIED
} state;
uint8_t *packet;
off_t pos;
unsigned int packet_len;
dns_callback_type func;
void *arg;
void *async_event;
#ifdef TWEETNACL
void *curve_plugin_data;
#endif
UT_hash_handle hh;
ref_entry_t ref;
};
/**
* IO channel for a specific DNS server
*/
struct rdns_io_channel {
struct rdns_server *srv;
struct rdns_resolver *resolver;
int sock; /**< persistent socket */
bool active;
void *async_io; /** async opaque ptr */
struct rdns_request *requests; /**< requests in flight */
uint64_t uses;
ref_entry_t ref;
};
struct rdns_resolver {
struct rdns_server *servers;
struct rdns_io_channel *io_channels; /**< hash of io chains indexed by socket */
struct rdns_async_context *async; /** async callbacks */
void *periodic; /** periodic event for resolver */
struct rdns_upstream_context *ups;
struct rdns_plugin *curve_plugin;
rdns_log_function logger;
void *log_data;
enum rdns_log_level log_level;
uint64_t max_ioc_uses;
void *refresh_ioc_periodic;
bool async_binded;
bool initialized;
ref_entry_t ref;
};
struct dns_header;
struct dns_query;
/* Internal DNS structs */
struct dns_header {
unsigned int qid :16;
#if BYTE_ORDER == BIG_ENDIAN
unsigned int qr:1;
unsigned int opcode:4;
unsigned int aa:1;
unsigned int tc:1;
unsigned int rd:1;
unsigned int ra:1;
unsigned int unused:3;
unsigned int rcode:4;
#else
unsigned int rd :1;
unsigned int tc :1;
unsigned int aa :1;
unsigned int opcode :4;
unsigned int qr :1;
unsigned int rcode :4;
unsigned int unused :3;
unsigned int ra :1;
#endif
unsigned int qdcount :16;
unsigned int ancount :16;
unsigned int nscount :16;
unsigned int arcount :16;
};
enum dns_section {
DNS_S_QD = 0x01,
#define DNS_S_QUESTION DNS_S_QD
DNS_S_AN = 0x02,
#define DNS_S_ANSWER DNS_S_AN
DNS_S_NS = 0x04,
#define DNS_S_AUTHORITY DNS_S_NS
DNS_S_AR = 0x08,
#define DNS_S_ADDITIONAL DNS_S_AR
DNS_S_ALL = 0x0f
};
/* enum dns_section */
enum dns_opcode {
DNS_OP_QUERY = 0,
DNS_OP_IQUERY = 1,
DNS_OP_STATUS = 2,
DNS_OP_NOTIFY = 4,
DNS_OP_UPDATE = 5,
};
/* dns_opcode */
enum dns_class {
DNS_C_IN = 1,
DNS_C_ANY = 255
};
/* enum dns_class */
struct dns_query {
char *qname;
unsigned int qtype :16;
unsigned int qclass :16;
};
enum dns_type {
DNS_T_A = RDNS_REQUEST_A,
DNS_T_NS = RDNS_REQUEST_NS,
DNS_T_CNAME = 5,
DNS_T_SOA = RDNS_REQUEST_SOA,
DNS_T_PTR = RDNS_REQUEST_PTR,
DNS_T_MX = RDNS_REQUEST_MX,
DNS_T_TXT = RDNS_REQUEST_TXT,
DNS_T_AAAA = RDNS_REQUEST_AAAA,
DNS_T_SRV = RDNS_REQUEST_SRV,
DNS_T_OPT = 41,
DNS_T_SSHFP = 44,
DNS_T_TLSA = RDNS_REQUEST_TLSA,
DNS_T_SPF = RDNS_REQUEST_SPF,
DNS_T_ALL = RDNS_REQUEST_ANY
};
/* enum dns_type */
static const char dns_rcodes[][32] = {
[RDNS_RC_NOERROR] = "no error",
[RDNS_RC_FORMERR] = "query format error",
[RDNS_RC_SERVFAIL] = "server fail",
[RDNS_RC_NXDOMAIN] = "no records with this name",
[RDNS_RC_NOTIMP] = "not implemented",
[RDNS_RC_REFUSED] = "query refused",
[RDNS_RC_YXDOMAIN] = "YXDOMAIN",
[RDNS_RC_YXRRSET] = "YXRRSET",
[RDNS_RC_NXRRSET] = "NXRRSET",
[RDNS_RC_NOTAUTH] = "not authorized",
[RDNS_RC_NOTZONE] = "no such zone",
[RDNS_RC_TIMEOUT] = "query timed out",
[RDNS_RC_NETERR] = "network error",
[RDNS_RC_NOREC] = "requested record is not found"
};
static const char dns_types[][16] = {
[RDNS_REQUEST_A] = "A request",
[RDNS_REQUEST_NS] = "NS request",
[RDNS_REQUEST_PTR] = "PTR request",
[RDNS_REQUEST_MX] = "MX request",
[RDNS_REQUEST_TXT] = "TXT request",
[RDNS_REQUEST_SRV] = "SRV request",
[RDNS_REQUEST_SPF] = "SPF request",
[RDNS_REQUEST_AAAA] = "AAAA request",
[RDNS_REQUEST_TLSA] = "TLSA request",
[RDNS_REQUEST_ANY] = "ANY request"
};
#endif /* DNS_PRIVATE_H_ */
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