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.\" $OpenBSD: getrrsetbyname.3,v 1.4 2001/08/08 16:28:43 jakob Exp $

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.Dd Oct 18, 2000

.Dt GETRRSETBYNAME 3

.Os

.Sh NAME

.Nm getrrsetbyname

.Nd retrieve DNS records

.Sh SYNOPSIS

.Fd #include 

.Ft int

.Fn getrrsetbyname "const char *hostname" "unsigned int rdclass" \

"unsigned int rdtype" "unsigned int flags" "struct rrsetinfo **res"

.Ft int

.Fn freerrset "struct rrsetinfo **rrset"

.Sh DESCRIPTION

.Fn getrrsetbyname

gets a set of resource records associated with a

.Fa hostname ,

.Fa class

and

.Fa type .

.Fa hostname

is a pointer a to null-terminated string.

The

.Fa flags

field is currently unused and must be zero.

.Pp

After a successful call to

.Fn getrrsetbyname ,

.Fa *res

is a pointer to an

.Li rrsetinfo

structure, containing a list of one or more

.Li rdatainfo

structures containing resource records and potentially another list of

.Li rdatainfo

structures containing SIG resource records associated with those records.

The members

.Li rri_rdclass

and

.Li rri_rdtype

are copied from the parameters.

.Li rri_ttl

and

.Li rri_name

are properties of the obtained rrset.

The resource records contained in

.Li rri_rdatas

and

.Li rri_sigs

are in uncompressed DNS wire format.

Properties of the rdataset are represented in the

.Li rri_flags

bitfield. If the

.Dv RRSET_VALIDATED

bit is set, the data has been DNSSEC

validated and the signatures verified.

.Pp

The following structures are used:

.Bd -literal -offset

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 */

};

.Ed

.Pp

All of the information returned by

.Fn getrrsetbyname

is dynamically allocated: the

.Li rrsetinfo

and

.Li rdatainfo

structures,

and the canonical host name strings pointed to by the

.Li rrsetinfostructure.

Memory allocated for the dynamically allocated structures created by

a successful call to

.Fn getrrsetbyname

is released by

.Fn freerrset .

.Li rrset

is a pointer to a

.Li struct rrset

created by a call to

.Fn getrrsetbyname .

.Pp

If the EDNS0 option is activated in

.Xr resolv.conf 3 ,

.Fn getrrsetbyname

will request DNSSEC authentication using the EDNS0 DNSSEC OK (DO) bit.

.Sh "RETURN VALUES"

.Fn getrrsetbyname

returns zero on success, and one of the following error

codes if an error occurred:

.Pp

.Bl -tag -width ERRSET_NOMEMORY -compact

.It Dv ERRSET_NONAME

the name does not exist

.It Dv ERRSET_NODATA

the name exists, but does not have data of the desired type

.It Dv ERRSET_NOMEMORY

memory could not be allocated

.It Dv ERRSET_INVAL

a parameter is invalid

.It Dv ERRSET_FAIL

other failure

.El

.Sh SEE ALSO

.Xr resolver 3 ,

.Xr resolv.conf 5 ,

.Xr named 8

.Sh AUTHORS

Jakob Schlyter

.Aq jakob@openbsd.org

.Sh HISTORY

.Fn getrrsetbyname

first appeared in

.Ox 3.0 .

The API first appeared in ISC BIND version 9.

.Sh BUGS

The data in

.Li *rdi_data

should be returned in uncompressed wire format.

Currently, the data is in compressed format and the caller can't

uncompress since it doesn't have the full message.

.Sh CAVEATS

The

.Dv RRSET_VALIDATED

flag in

.Li rri_flags

is set if the AD (autenticated data) bit in the DNS answer is

set. This flag

.Em should not

be trusted unless the transport between the nameserver and the resolver

is secure (e.g. IPsec, trusted network, loopback communication).