denser.h

#ifndef DENSER_H
#define DENSER_H

#include <inttypes.h>
#include <netinet/in.h>
#include <sys/time.h>

/* Size limits ( rfc 1035 2.3.4 ) */
#define DNSR_MAX_FIELD 2 /* Field width in bytes */
#define DNSR_MAX_LABEL 63
#define DNSR_MAX_LINE 1024
#define DNSR_MAX_HOSTNAME 253 /* Max conventional ASCII representation */
#define DNSR_MAX_NAME 255
#define DNSR_MAX_STRING 256 /* rfc 1034 3.3 */
#define DNSR_MAX_UDP_BASIC 512
#define DNSR_MAX_UDP 1280 /* RFC 6891 6.2.3 */
#define DNSR_MAX_NS 4     /* Max number of name servers */
#define DNSR_MAX_RDATA (uint16_t)65535
#define DNSR_MAX_ERRNO 31 /* Highest valid error number */
#define DNSR_MAX_TYPE 255 /* Highest valid type */
#define DNSR_MAX_CLASS 4  /* Highest valid class */

/* RR types ( RFC 1035 3.2.2 ) */
#define DNSR_TYPE_A 1      /* Host address */
#define DNSR_TYPE_NS 2     /* Authoritative name server */
#define DNSR_TYPE_MD 3     /* Mail destination */
#define DNSR_TYPE_MF 4     /* Mail forwarder */
#define DNSR_TYPE_CNAME 5  /* Canonical name for an alias */
#define DNSR_TYPE_SOA 6    /* Start of a zone of authority */
#define DNSR_TYPE_MB 7     /* Mailbox domain */
#define DNSR_TYPE_MG 8     /* Mail group member */
#define DNSR_TYPE_MR 9     /* Mail rename domain name */
#define DNSR_TYPE_NULL 10  /* Null RR */
#define DNSR_TYPE_WKS 11   /* Well known service description */
#define DNSR_TYPE_PTR 12   /* Domain name pointer */
#define DNSR_TYPE_HINFO 13 /* Host information */
#define DNSR_TYPE_MINFO 14 /* Mailbox or mail list information */
#define DNSR_TYPE_MX 15    /* Mail exchange */
#define DNSR_TYPE_TXT 16   /* Text string */
#define DNSR_TYPE_AAAA 28  /* IPv6 AAAA type */
#define DNSR_TYPE_SRV 33   /* Service Record RFC 2728 */
#define DNSR_TYPE_OPT 41   /* EDNS0 OPT pseudo-RR, RFC 6891 */
#define DNSR_TYPE_ALL 255  /* All records */

/* RR query types ( rfc 1035 3.2.3 ) */
#define DNSR_TYPE_AXFR 252 /* Request transfer of an entire zone */
//#define DNSR_TYPE_MAILB 253   /* Request mail-box related records */
//#define DNSR_TYPE_MAILA 254   /* Request for mail agent records */
//#define DNSR_TYPE_ALL 255     /* Request all records */

/* RR class values ( RFC 6895 3.2 ) */
#define DNSR_CLASS_IN 1 /* Internet */
#define DNSR_CLASS_CH 3 /* CHAOS */
#define DNSR_CLASS_HS 4 /* HESIOD */

/* RR qclass values ( RFC 6895 3.2 ) */
#define DNSR_CLASS_NONE 254 /* RFC 2136 Dynamic Updates */
#define DNSR_CLASS_ALL 255  /* Any class */

/* DNSR flags */
#define DNSR_FLAG_ON 0        /* Turn flag on */
#define DNSR_FLAG_OFF 1       /* Turn flag off */
#define DNSR_FLAG_RECURSION 2 /* Recursion */

/* DNSR error codes */
#define DNSR_ERROR_NONE 0   /* No error condition */
#define DNSR_ERROR_FORMAT 1 /* Format error */
#define DNSR_ERROR_SERVER 2 /* Server failure */
#define DNSR_ERROR_NAME                                                        \
    3                                /* Name error - Meaningful only
                                                 * for responses from an
                                                 * authoritative name server,
                                                 * name does not exist */
#define DNSR_ERROR_NOT_IMPLEMENTED 4 /* Not implemented */
#define DNSR_ERROR_REFUSED 5         /* Operation refused */
                                     /* 6 and 7 reserverd for future
                                                 * RC values */

#define DNSR_ERROR_CONFIG 8 /* Config file error */
#define DNSR_ERROR_NO_QUERY                                                    \
    9                         /* dnsr_rr called without
                                                 * query being sent */
#define DNSR_ERROR_TIMEOUT 10 /* Timeout */
#define DNSR_ERROR_ID_WRONG                                                    \
    11                             /* rr ID does not match
                                                 * query ID */
#define DNSR_ERROR_NOT_RESPONSE 12 /* NS did not return a resp */
#define DNSR_ERROR_NO_RECURSION                                                \
    13 /* NS does not offer
                                                 * recursion */
#define DNSR_ERROR_QUESTION_WRONG                                              \
    14                                   /* rr question does not
                                                 * match query question */
#define DNSR_ERROR_NO_ANSWER 15          /* No answer in rr */
#define DNSR_ERROR_TRUNCATION 16         /* Response truncated */
#define DNSR_ERROR_SYSTEM 17             /* System error. See errono. */
#define DNSR_ERROR_SIZELIMIT_EXCEEDED 18 /* Size limit exceeded */
#define DNSR_ERROR_NS_INVALID 19         /* Invalid NS */
#define DNSR_ERROR_NS_DEAD 20            /* NS dead */
#define DNSR_ERROR_TV 21                 /* Time Vale negative */
#define DNSR_ERROR_FD_SET 22             /* Wrong FD selected */
#define DNSR_ERROR_PARSE 23              /* Parse error */
#define DNSR_ERROR_STATE 24              /* Unknown state */
#define DNSR_ERROR_TYPE 25               /* Unknown type */
#define DNSR_ERROR_RCODE 26              /* Unknown rcode */
#define DNSR_ERROR_TOGGLE 27             /* Unknown toggle */
#define DNSR_ERROR_FLAG 28               /* Unknown flag */
#define DNSR_ERROR_CLASS 29              /* Unknown class */
#define DNSR_ERROR_Z 30                  /* Z code not zero */
#define DNSR_ERROR_CONNECTION_CLOSED 31  /* Z code not zero */
#define DNSR_ERROR_UNKNOWN 32            /* Unknown error */

struct dnsr_result {
    struct dnsr_rr *r_answer;
    struct dnsr_rr *r_ns;
    struct dnsr_rr *r_additional;
    unsigned int    r_ancount;
    unsigned int    r_nscount;
    unsigned int    r_arcount;
    uint16_t        r_rcode;
};

typedef struct dnsr DNSR;

/*
 * 3.3. Standard RRs
 *
 * The following RR definitions are expected to occur, at least
 * potentially, in all classes.  In particular, NS, SOA, CNAME, and PTR
 * will be used in all classes, and have the same format in all classes.
 * Because their RDATA format is known, all domain names in the RDATA
 * section of these RRs may be compressed.
 *
 * <domain-name> is a domain name represented as a series of labels, and
 * terminated by a label with zero length.  <character-string> is a single
 * length octet followed by that number of characters.  <character-string>
 * is treated as binary information, and can be up to 256 characters in
 * length (including the length octet).
 */

/* Generic RR Domain */
struct rr_dn {
    char dn_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.1. CNAME RDATA format */
struct rr_cname {
    char cn_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.2. HINFO RDATA format */
struct rr_hinfo {
    char hi_cpu[ DNSR_MAX_STRING + 1 ];
    char hi_os[ DNSR_MAX_STRING + 1 ];
};

/* 3.3.3. MB RDATA format */
struct rr_mb {
    char mb_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.4. MD RDATA format */
struct rr_md {
    char md_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.5. MF RDATA format */
struct rr_mf {
    char mf_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.6. MG RDATA format */
struct rr_mg {
    char mg_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.7. MINFO RDATA format */
struct rr_minfo {
    char mi_rmailbx[ DNSR_MAX_NAME + 1 ];
    char mi_emailbx[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.8. MR RDATA format */
struct rr_mr {
    char mr_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.9. MX RDATA format */
struct rr_mx {
    uint16_t mx_preference;
    char     mx_exchange[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.10. NULL RDATA format */
struct rr_null {
    char null_name[ DNSR_MAX_RDATA ];
};

/* 3.3.11. NS RDATA format */
struct rr_ns {
    char ns_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.12. PTR RDATA format */
struct rr_ptr {
    char ptr_name[ DNSR_MAX_NAME + 1 ];
};

/* 3.3.13 SOA RDATA format */
struct rr_soa {
    char    soa_mname[ DNSR_MAX_NAME + 1 ];
    char    soa_rname[ DNSR_MAX_NAME + 1 ];
    int     soa_serial;
    int32_t soa_refresh;
    int32_t soa_retry;
    int32_t soa_expire;
    int32_t soa_minimum;
};

/* 3.3.14. TXT RDATA format */
struct dnsr_string {
    struct dnsr_string *s_next;
    char                s_string[ DNSR_MAX_STRING + 1 ];
};

struct rr_txt {
    struct dnsr_string *txt_data;
};

/*
 * 3.4. Internet specific RRs
 */

/* 3.4.1. A RDATA format */
struct rr_a {
    struct in_addr a_address;
};

struct rr_aaaa {
    struct in6_addr aaaa_address;
};

/* RFC 2782 SRV record */
struct rr_srv {
    uint16_t srv_priority;
    uint16_t srv_weight;
    uint16_t srv_port;
    char     srv_target[ DNSR_MAX_NAME + 1 ];
};

/* RFC 6891 OPT record */
struct edns_opt {
    struct edns_opt *opt_next;
    uint8_t         *opt_data;
    uint16_t         opt_code;
    uint16_t         opt_len;
};

struct rr_opt {
    struct edns_opt *opt_opt;
    uint8_t          opt_rcode;
    uint8_t          opt_version;
    uint16_t         opt_flags;
    uint16_t         opt_udp;
};

struct ip_info {
    struct ip_info         *ip_next;
    struct sockaddr_storage ip_sa;
};

struct dnsr_rr {
    char            rr_name[ DNSR_MAX_NAME + 1 ]; /* domain name */
    struct ip_info *rr_ip;                        /* related IP */
    uint16_t        rr_type;                      /* RR type */
    uint16_t        rr_class;                     /* RR class */
    uint32_t        rr_ttl;                       /* RR ttl */
    uint16_t        rr_rdlength;                  /* length of RDATA field */
    union {
        struct rr_dn rd_dn;
#define rr_dn rr_u.rd_dn
        struct rr_cname rd_cname;
#define rr_cname rr_u.rd_cname
        struct rr_hinfo rd_hinfo;
#define rr_hinfo rr_u.rd_hinfo
        struct rr_mb rd_mb;
#define rr_mb rr_u.rd_mb
        struct rr_md rd_md;
#define rr_md rr_u.rd_md
        struct rr_mf rd_mf;
#define rr_mf rr_u.rd_mf
        struct rr_mg rd_mg;
#define rr_mg rr_u.rd_mg
        struct rr_minfo rd_minfo;
#define rr_minfo rr_u.rd_minfo
        struct rr_mr rd_mr;
#define rr_mr rr_u.rd_mr
        struct rr_mx rd_mx;
#define rr_mx rr_u.rd_mx
        struct rr_null rd_null;
#define rr_null rr_u.rd_null
        struct rr_ns rd_ns;
#define rr_ns rr_u.rd_ns
        struct rr_ptr rd_ptr;
#define rr_ptr rr_u.rd_ptr
        struct rr_soa rd_soa;
#define rr_soa rr_u.rd_soa
        struct rr_txt rd_txt;
#define rr_txt rr_u.rd_txt
        struct rr_a rd_a;
#define rr_a rr_u.rd_a
        struct rr_aaaa rd_aaaa;
#define rr_aaaa rr_u.rd_aaaa
        struct rr_srv rd_srv;
#define rr_srv rr_u.rd_srv
        struct rr_opt rd_opt;
#define rr_opt rr_u.rd_opt
    } rr_u;
};

DNSR *dnsr_new(void);
int   dnsr_nameserver(DNSR *dnsr, const char *server);
int   dnsr_nameserver_port(DNSR *dnsr, const char *server, const char *port);
int   dnsr_config(DNSR *dnsr, int flag, int toggle);
int   dnsr_query(DNSR *dnsr, uint16_t qtype, uint16_t qclass, const char *dn);
struct dnsr_result *dnsr_result(DNSR *dnsr, struct timeval *timeout);
int                 dnsr_result_expired(DNSR *dnsr, struct dnsr_result *result);

char *dnsr_ntoptr(DNSR *, int, const void *, const char *);
char *dnsr_reverse_ip(DNSR *, const char *, const char *);

int   dnsr_errno(DNSR *dnser);
void  dnsr_errclear(DNSR *dnser);
char *dnsr_err2string(int dnsr_errno);
void  dnsr_perror(DNSR *dnsr, const char *s);

void dnsr_free(DNSR *dnsr);
void dnsr_free_result(struct dnsr_result *result);
void dnsr_free_val(void *);

int dnsr_send_query(DNSR *dnsr, int ns);

#endif /* DENSER_H */