getrrset.c revision 70e5a7403f0e0a3bd292b8287c5fed5772c15270
/*
* Copyright (C) 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 2000-2003 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: getrrset.c,v 1.18 2007/06/19 23:47:22 tbox Exp $ */
/*! \file */
/**
* DESCRIPTION
*
* 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().
*
* The following structures are used:
*
* \code
* 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
* };
* \endcode
*
* \section getrrset_return Return Values
*
* lwres_getrrsetbyname() returns zero on success, and one of the
* following error codes if an error occurred:
*
* \li #ERRSET_NONAME: the name does not exist
*
* \li #ERRSET_NODATA:
* the name exists, but does not have data of the desired type
*
* \li #ERRSET_NOMEMORY:
* memory could not be allocated
*
* \li #ERRSET_INVAL:
* a parameter is invalid
*
* \li #ERRSET_FAIL:
* other failure
*/
#include <config.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <lwres/lwres.h>
#include <lwres/net.h>
#include <lwres/netdb.h> /* XXX #include <netdb.h> */
#include "assert_p.h"
/*!
* Structure to map results
*/
static unsigned int
lwresult_to_result(lwres_result_t lwresult) {
switch (lwresult) {
case LWRES_R_SUCCESS: return (ERRSET_SUCCESS);
case LWRES_R_NOMEMORY: return (ERRSET_NOMEMORY);
case LWRES_R_NOTFOUND: return (ERRSET_NONAME);
case LWRES_R_TYPENOTFOUND: return (ERRSET_NODATA);
default: return (ERRSET_FAIL);
}
}
/*@{*/
/*!
* malloc / calloc functions that guarantee to only
* return NULL if there is an error, like they used
* to before the ANSI C committee broke them.
*/
static void *
sane_malloc(size_t size) {
if (size == 0U)
size = 1;
return (malloc(size));
}
static void *
sane_calloc(size_t number, size_t size) {
size_t len = number * size;
void *mem = sane_malloc(len);
if (mem != NULL)
memset(mem, 0, len);
return (mem);
}
/*@}*/
/*% Returns a set of resource records associated with a hostname, class, and type. hostname is a pointer a to null-terminated string. */
int
lwres_getrrsetbyname(const char *hostname, unsigned int rdclass,
unsigned int rdtype, unsigned int flags,
struct rrsetinfo **res)
{
lwres_context_t *lwrctx = NULL;
lwres_result_t lwresult;
lwres_grbnresponse_t *response = NULL;
struct rrsetinfo *rrset = NULL;
unsigned int i;
unsigned int lwflags;
unsigned int result;
if (rdclass > 0xffff || rdtype > 0xffff) {
result = ERRSET_INVAL;
goto fail;
}
/*
* Don't allow queries of class or type ANY
*/
if (rdclass == 0xff || rdtype == 0xff) {
result = ERRSET_INVAL;
goto fail;
}
lwresult = lwres_context_create(&lwrctx, NULL, NULL, NULL, 0);
if (lwresult != LWRES_R_SUCCESS) {
result = lwresult_to_result(lwresult);
goto fail;
}
(void) lwres_conf_parse(lwrctx, lwres_resolv_conf);
/*
* If any input flags were defined, lwflags would be set here
* based on them
*/
UNUSED(flags);
lwflags = 0;
lwresult = lwres_getrdatabyname(lwrctx, hostname,
(lwres_uint16_t)rdclass,
(lwres_uint16_t)rdtype,
lwflags, &response);
if (lwresult != LWRES_R_SUCCESS) {
result = lwresult_to_result(lwresult);
goto fail;
}
rrset = sane_malloc(sizeof(struct rrsetinfo));
if (rrset == NULL) {
result = ERRSET_NOMEMORY;
goto fail;
}
rrset->rri_name = NULL;
rrset->rri_rdclass = response->rdclass;
rrset->rri_rdtype = response->rdtype;
rrset->rri_ttl = response->ttl;
rrset->rri_flags = 0;
rrset->rri_nrdatas = 0;
rrset->rri_rdatas = NULL;
rrset->rri_nsigs = 0;
rrset->rri_sigs = NULL;
rrset->rri_name = sane_malloc(response->realnamelen + 1);
if (rrset->rri_name == NULL) {
result = ERRSET_NOMEMORY;
goto fail;
}
strncpy(rrset->rri_name, response->realname, response->realnamelen);
rrset->rri_name[response->realnamelen] = 0;
if ((response->flags & LWRDATA_VALIDATED) != 0)
rrset->rri_flags |= RRSET_VALIDATED;
rrset->rri_nrdatas = response->nrdatas;
rrset->rri_rdatas = sane_calloc(rrset->rri_nrdatas,
sizeof(struct rdatainfo));
if (rrset->rri_rdatas == NULL) {
result = ERRSET_NOMEMORY;
goto fail;
}
for (i = 0; i < rrset->rri_nrdatas; i++) {
rrset->rri_rdatas[i].rdi_length = response->rdatalen[i];
rrset->rri_rdatas[i].rdi_data =
sane_malloc(rrset->rri_rdatas[i].rdi_length);
if (rrset->rri_rdatas[i].rdi_data == NULL) {
result = ERRSET_NOMEMORY;
goto fail;
}
memcpy(rrset->rri_rdatas[i].rdi_data, response->rdatas[i],
rrset->rri_rdatas[i].rdi_length);
}
rrset->rri_nsigs = response->nsigs;
rrset->rri_sigs = sane_calloc(rrset->rri_nsigs,
sizeof(struct rdatainfo));
if (rrset->rri_sigs == NULL) {
result = ERRSET_NOMEMORY;
goto fail;
}
for (i = 0; i < rrset->rri_nsigs; i++) {
rrset->rri_sigs[i].rdi_length = response->siglen[i];
rrset->rri_sigs[i].rdi_data =
sane_malloc(rrset->rri_sigs[i].rdi_length);
if (rrset->rri_sigs[i].rdi_data == NULL) {
result = ERRSET_NOMEMORY;
goto fail;
}
memcpy(rrset->rri_sigs[i].rdi_data, response->sigs[i],
rrset->rri_sigs[i].rdi_length);
}
lwres_grbnresponse_free(lwrctx, &response);
lwres_conf_clear(lwrctx);
lwres_context_destroy(&lwrctx);
*res = rrset;
return (ERRSET_SUCCESS);
fail:
if (rrset != NULL)
lwres_freerrset(rrset);
if (response != NULL)
lwres_grbnresponse_free(lwrctx, &response);
if (lwrctx != NULL) {
lwres_conf_clear(lwrctx);
lwres_context_destroy(&lwrctx);
}
return (result);
}
/*% Releases memory allocated for the dynamically allocated structures created by a successful call to lwres_getrrsetbyname(). */
void
lwres_freerrset(struct rrsetinfo *rrset) {
unsigned int i;
for (i = 0; i < rrset->rri_nrdatas; i++) {
if (rrset->rri_rdatas[i].rdi_data == NULL)
break;
free(rrset->rri_rdatas[i].rdi_data);
}
free(rrset->rri_rdatas);
for (i = 0; i < rrset->rri_nsigs; i++) {
if (rrset->rri_sigs[i].rdi_data == NULL)
break;
free(rrset->rri_sigs[i].rdi_data);
}
free(rrset->rri_sigs);
free(rrset->rri_name);
free(rrset);
}