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"LWRES_GETRRSETBYNAME" ("3") | C library functions | Unix Manual Pages | :man


lwres_getrrsetbyname, lwres_freerrset - retrieve DNS records




#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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