lwres_getrrsetbyname, lwres_freerrset — retrieve DNS records
#include <lwres/netdb.h>
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int
lwres_getrrsetbyname( | , | |
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void
lwres_freerrset( | ); | |
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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 */
};
lwres_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
lwres_getrrsetbyname(),
*res
is a pointer to an
rrsetinfo
structure, containing a list of one or more
rdatainfo
structures 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.  
All of the information returned by
lwres_getrrsetbyname()
is dynamically allocated: 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
lwres_getrrsetbyname()
is released by
lwres_freerrset().
rrset
is a pointer to a
struct rrset
created by a call to
lwres_getrrsetbyname().
lwres_getrrsetbyname()
returns zero on success, and one of the following error
codes if an error occurred:
ERRSET_NONAMEthe name does not exist
ERRSET_NODATAthe name exists, but does not have data of the desired type
ERRSET_NOMEMORYmemory could not be allocated
ERRSET_INVALa parameter is invalid
ERRSET_FAILother failure