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# getrrsetbyname

    GETRRSETBYNAME(3)       System Library Functions Manual      GETRRSETBYNAME(3)

    NAME
         getrrsetbyname - retrieve DNS records

    SYNOPSIS
         #include <netdb.h>

         int
         getrrsetbyname(const char *hostname, unsigned int rdclass,
                 unsigned int rdtype, unsigned int flags, struct rrsetinfo **res);

         int
         freerrset(struct rrsetinfo **rrset);

    DESCRIPTION
         getrrsetbyname() gets a set of resource records associated with a
         hostname, class and type.  hostname is a pointer a to null-terminated
         string.  The flags field is currently unused and must be zero.

         After a successful call to getrrsetbyname(), *res is a pointer to an
         rrsetinfo structure, containing a list of one or more rdatainfo struc-
         tures containing resource records and potentially another list of
         rdatainfo structures containing SIG resource records associated with
         those records.  The members rri_rdclass and rri_rdtype are copied from
         the parameters.  rri_ttl and rri_name are properties of the obtained
         rrset.  The resource records contained in rri_rdatas and rri_sigs are in
         uncompressed DNS wire format.  Properties of the rdataset are represented
         in the rri_flags bitfield. If the RRSET_VALIDATED bit is set, the data
         has been DNSSEC validated and the signatures verified.

         The following structures are used:

         struct  rdatainfo {
                 unsigned int            rdi_length;     /* length of data */
                 unsigned char           *rdi_data;      /* record data */
         };

         struct  rrsetinfo {
                 unsigned int            rri_flags;      /* RRSET_VALIDATED ... */
                 unsigned int            rri_rdclass;    /* class number */
                 unsigned int            rri_rdtype;     /* RR type number */
                 unsigned int            rri_ttl;        /* time to live */
                 unsigned int            rri_nrdatas;    /* size of rdatas array */
                 unsigned int            rri_nsigs;      /* size of sigs array */
                 char                    *rri_name;      /* canonical name */
                 struct rdatainfo        *rri_rdatas;    /* individual records */
                 struct rdatainfo        *rri_sigs;      /* individual signatures */
         };

         All of the information returned by getrrsetbyname() is dynamically allo-
         cated: the rrsetinfo and rdatainfo structures, and the canonical host
         name strings pointed to by the rrsetinfostructure. Memory allocated for
         the dynamically allocated structures created by a successful call to
         getrrsetbyname() is released by freerrset().  rrset is a pointer to a
         struct rrset created by a call to getrrsetbyname().

         If the EDNS0 option is activated in resolv.conf(3), getrrsetbyname() will
         request DNSSEC authentication using the EDNS0 DNSSEC OK (DO) bit.

    RETURN VALUES
         getrrsetbyname() returns zero on success, and one of the following error
         codes if an error occurred:

         ERRSET_NONAME    the name does not exist
         ERRSET_NODATA    the name exists, but does not have data of the desired
                          type
         ERRSET_NOMEMORY  memory could not be allocated
         ERRSET_INVAL     a parameter is invalid
         ERRSET_FAIL      other failure

    SEE ALSO
         resolver(3), resolv.conf(5), named(8)

    AUTHORS
         Jakob Schlyter <jakob@openbsd.org>

    HISTORY
         getrrsetbyname() first appeared in OpenBSD 3.0.  The API first appeared
         in ISC BIND version 9.

    BUGS
         The data in *rdi_data should be returned in uncompressed wire format.
         Currently, the data is in compressed format and the caller can't uncom-
         press since it doesn't have the full message.

    CAVEATS
         The RRSET_VALIDATED flag in rri_flags is set if the AD (autenticated
         data) bit in the DNS answer is set. This flag should not be trusted
         unless the transport between the nameserver and the resolver is secure
         (e.g. IPsec, trusted network, loopback communication).

    BSD                              Oct 18, 2000                              BSD

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