lwres_getrrsetbyname(3) retrieve DNS records

Other Alias



#include <lwres/netdb.h>

int lwres_getrrsetbyname(const char *hostname, unsigned int rdclass, unsigned int rdtype, unsigned int flags, struct rrsetinfo **res);
void lwres_freerrset(struct rrsetinfo *rrset);

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:


the name does not exist


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


memory could not be allocated


a parameter is invalid


other failure


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