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:
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
Copyright © 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
Copyright © 2000, 2001 Internet Software Consortium.