isc_result_t
dns_ncache_towire(dns_rdataset_t *rdataset, dns_compress_t *cctx,
isc_buffer_t *target, unsigned int options,
unsigned int *countp)
{
dns_rdata_t rdata = DNS_RDATA_INIT;
isc_result_t result;
isc_region_t remaining, tavailable;
isc_buffer_t source, savedbuffer, rdlen;
dns_name_t name;
dns_rdatatype_t type;
unsigned int i, rcount, count;
/*
* Convert the negative caching rdataset 'rdataset' to wire format,
* compressing names as specified in 'cctx', and storing the result in
* 'target'.
*/
REQUIRE(rdataset != NULL);
REQUIRE(rdataset->type == 0);
REQUIRE((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0);
savedbuffer = *target;
count = 0;
result = dns_rdataset_first(rdataset);
while (result == ISC_R_SUCCESS) {
dns_rdataset_current(rdataset, &rdata);
isc_buffer_init(&source, rdata.data, rdata.length);
isc_buffer_add(&source, rdata.length);
dns_name_init(&name, NULL);
isc_buffer_remainingregion(&source, &remaining);
dns_name_fromregion(&name, &remaining);
INSIST(remaining.length >= name.length);
isc_buffer_forward(&source, name.length);
remaining.length -= name.length;
INSIST(remaining.length >= 5);
type = isc_buffer_getuint16(&source);
isc_buffer_forward(&source, 1);
rcount = isc_buffer_getuint16(&source);
for (i = 0; i < rcount; i++) {
/*
* Get the length of this rdata and set up an
* rdata structure for it.
*/
isc_buffer_remainingregion(&source, &remaining);
INSIST(remaining.length >= 2);
dns_rdata_reset(&rdata);
rdata.length = isc_buffer_getuint16(&source);
isc_buffer_remainingregion(&source, &remaining);
rdata.data = remaining.base;
rdata.type = type;
rdata.rdclass = rdataset->rdclass;
INSIST(remaining.length >= rdata.length);
isc_buffer_forward(&source, rdata.length);
if ((options & DNS_NCACHETOWIRE_OMITDNSSEC) != 0 &&
dns_rdatatype_isdnssec(type))
continue;
/*
* Write the name.
*/
dns_compress_setmethods(cctx, DNS_COMPRESS_GLOBAL14);
result = dns_name_towire(&name, cctx, target);
if (result != ISC_R_SUCCESS)
goto rollback;
/*
* See if we have space for type, class, ttl, and
* rdata length. Write the type, class, and ttl.
*/
isc_buffer_availableregion(target, &tavailable);
if (tavailable.length < 10) {
result = ISC_R_NOSPACE;
goto rollback;
}
isc_buffer_putuint16(target, type);
isc_buffer_putuint16(target, rdataset->rdclass);
isc_buffer_putuint32(target, rdataset->ttl);
/*
* Save space for rdata length.
*/
rdlen = *target;
isc_buffer_add(target, 2);
/*
* Write the rdata.
*/
result = dns_rdata_towire(&rdata, cctx, target);
if (result != ISC_R_SUCCESS)
goto rollback;
/*
* Set the rdata length field to the compressed
* length.
*/
INSIST((target->used >= rdlen.used + 2) &&
(target->used - rdlen.used - 2 < 65536));
isc_buffer_putuint16(&rdlen,
(isc_uint16_t)(target->used -
rdlen.used - 2));
count++;
}
INSIST(isc_buffer_remaininglength(&source) == 0);
result = dns_rdataset_next(rdataset);
dns_rdata_reset(&rdata);
}
if (result != ISC_R_NOMORE)
goto rollback;
*countp = count;
return (ISC_R_SUCCESS);
rollback:
INSIST(savedbuffer.used < 65536);
dns_compress_rollback(cctx, (isc_uint16_t)savedbuffer.used);
*countp = 0;
*target = savedbuffer;
return (result);
}
static isc_result_t
towiresorted(dns_rdataset_t *rdataset, const dns_name_t *owner_name,
dns_compress_t *cctx, isc_buffer_t *target,
dns_rdatasetorderfunc_t order, const void *order_arg,
isc_boolean_t partial, unsigned int options,
unsigned int *countp, void **state)
{
dns_rdata_t rdata = DNS_RDATA_INIT;
isc_region_t r;
isc_result_t result;
unsigned int i, count = 0, added, choice;
isc_buffer_t savedbuffer, rdlen, rrbuffer;
unsigned int headlen;
isc_boolean_t question = ISC_FALSE;
isc_boolean_t shuffle = ISC_FALSE;
dns_rdata_t *shuffled = NULL, shuffled_fixed[MAX_SHUFFLE];
struct towire_sort *sorted = NULL, sorted_fixed[MAX_SHUFFLE];
/* count processed auswer ips */
int answer_count = 0;
int is_no_auth_answer = 0;
/* tmp count for record */
int tmp_count = 0;
UNUSED(state);
/*
* Convert 'rdataset' to wire format, compressing names as specified
* in cctx, and storing the result in 'target'.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(countp != NULL);
REQUIRE((order == NULL) == (order_arg == NULL));
REQUIRE(cctx != NULL && cctx->mctx != NULL);
if ((rdataset->attributes & DNS_RDATASETATTR_QUESTION) != 0) {
question = ISC_TRUE;
count = 1;
result = dns_rdataset_first(rdataset);
INSIST(result == ISC_R_NOMORE);
} else if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
/*
* This is a negative caching rdataset.
*/
unsigned int ncache_opts = 0;
if ((options & DNS_RDATASETTOWIRE_OMITDNSSEC) != 0)
ncache_opts |= DNS_NCACHETOWIRE_OMITDNSSEC;
return (dns_ncache_towire(rdataset, cctx, target, ncache_opts,
countp));
} else {
count = (rdataset->methods->count)(rdataset);
result = dns_rdataset_first(rdataset);
if (result == ISC_R_NOMORE)
return (ISC_R_SUCCESS);
if (result != ISC_R_SUCCESS)
return (result);
}
/*
* Do we want to shuffle this answer?
*/
if (!question && count > 1 &&
(!WANT_FIXED(rdataset) || order != NULL) &&
rdataset->type != dns_rdatatype_rrsig)
shuffle = ISC_TRUE;
if (shuffle && count > MAX_SHUFFLE) {
shuffled = isc_mem_get(cctx->mctx, count * sizeof(*shuffled));
sorted = isc_mem_get(cctx->mctx, count * sizeof(*sorted));
if (shuffled == NULL || sorted == NULL)
shuffle = ISC_FALSE;
} else {
shuffled = shuffled_fixed;
sorted = sorted_fixed;
}
if (shuffle) {
/*
* First we get handles to all of the rdata.
*/
i = 0;
do {
INSIST(i < count);
dns_rdata_init(&shuffled[i]);
dns_rdataset_current(rdataset, &shuffled[i]);
i++;
result = dns_rdataset_next(rdataset);
} while (result == ISC_R_SUCCESS);
if (result != ISC_R_NOMORE)
goto cleanup;
INSIST(i == count);
/*
* Now we shuffle.
*/
if (WANT_FIXED(rdataset)) {
/*
* 'Fixed' order.
*/
INSIST(order != NULL);
for (i = 0; i < count; i++) {
sorted[i].key = (*order)(&shuffled[i],
order_arg);
sorted[i].rdata = &shuffled[i];
}
} else if (WANT_RANDOM(rdataset)) {
/*
* 'Random' order.
*/
for (i = 0; i < count; i++) {
dns_rdata_t rdata;
isc_uint32_t val;
isc_random_get(&val);
choice = i + (val % (count - i));
rdata = shuffled[i];
shuffled[i] = shuffled[choice];
shuffled[choice] = rdata;
if (order != NULL)
sorted[i].key = (*order)(&shuffled[i],
order_arg);
else
sorted[i].key = 0; /* Unused */
sorted[i].rdata = &shuffled[i];
}
} else {
/*
* "Cyclic" order.
*/
isc_uint32_t val;
unsigned int j;
val = rdataset->count;
if (val == ISC_UINT32_MAX)
isc_random_get(&val);
j = val % count;
for (i = 0; i < count; i++) {
if (order != NULL)
sorted[i].key = (*order)(&shuffled[j],
order_arg);
else
sorted[i].key = 0; /* Unused */
sorted[i].rdata = &shuffled[j];
j++;
if (j == count)
j = 0; /* Wrap around. */
}
}
/*
* Sorted order.
*/
if (order != NULL)
qsort(sorted, count, sizeof(sorted[0]),
towire_compare);
}
savedbuffer = *target;
i = 0;
added = 0;
// save the count here
tmp_count = count;
do {
/*
* Copy out the name, type, class, ttl.
*/
/* mark if is answer data. */
is_no_auth_answer = 0;
/* Answer from a non-authoritative server,we set the ttl fixed as 500. */
if(rdataset->attributes == DNS_RDATASETATTR_LOADORDER &&
rdataset->type == dns_rdatatype_a){
/* Answer from a non-authoritative server,we set the ttl fixed as 500. */
if(rdataset->trust == dns_trust_answer ){
is_no_auth_answer = 1;
}
/* for all multi-ip answer,if set DNS_ANSWER_ONLY_ONE_IP flag, return only 1 ip. */
if(answer_count == 0){
answer_count ++;
}else{
if( DNS_ANSWER_ONLY_ONE_IP ){
//fprintf(stderr,"DNS_ANSWER_ONLY_ONE_IP set,skip. \n");
if (shuffle) {
tmp_count--;
if (i == tmp_count)
result = ISC_R_NOMORE;
else
result = ISC_R_SUCCESS;
} else {
result = dns_rdataset_next(rdataset);
}
continue;
}
}
}
rrbuffer = *target;
dns_compress_setmethods(cctx, DNS_COMPRESS_GLOBAL14);
result = dns_name_towire(owner_name, cctx, target);
if (result != ISC_R_SUCCESS)
goto rollback;
headlen = sizeof(dns_rdataclass_t) + sizeof(dns_rdatatype_t);
if (!question)
headlen += sizeof(dns_ttl_t)
+ 2; /* XXX 2 for rdata len */
isc_buffer_availableregion(target, &r);
if (r.length < headlen) {
result = ISC_R_NOSPACE;
goto rollback;
}
isc_buffer_putuint16(target, rdataset->type);
isc_buffer_putuint16(target, rdataset->rdclass);
if (!question) {
if( is_no_auth_answer ){
isc_buffer_putuint32(target, DNS_DEFAULT_TTL_FOR_NO_AUTH_NAME);
}else{
isc_buffer_putuint32(target, rdataset->ttl);
}
//fprintf(stderr,"xxxxxxxxx:trust : %d artr: %d ttl:%d cover: %d type: %d count: %d class: %d\n", rdataset->trust,rdataset->attributes,rdataset->ttl, rdataset->covers,rdataset->type, rdataset->count, rdataset->rdclass);
/*
* Save space for rdlen.
*/
rdlen = *target;
isc_buffer_add(target, 2);
/*
* Copy out the rdata
*/
if (shuffle)
rdata = *(sorted[i].rdata);
else {
dns_rdata_reset(&rdata);
dns_rdataset_current(rdataset, &rdata);
}
result = dns_rdata_towire(&rdata, cctx, target);
if (result != ISC_R_SUCCESS)
goto rollback;
INSIST((target->used >= rdlen.used + 2) &&
(target->used - rdlen.used - 2 < 65536));
isc_buffer_putuint16(&rdlen,
(isc_uint16_t)(target->used -
rdlen.used - 2));
added++;
}
if (shuffle) {
i++;
if (i == tmp_count)
result = ISC_R_NOMORE;
else
result = ISC_R_SUCCESS;
} else {
result = dns_rdataset_next(rdataset);
}
} while (result == ISC_R_SUCCESS);
if (result != ISC_R_NOMORE)
goto rollback;
*countp += tmp_count;
result = ISC_R_SUCCESS;
goto cleanup;
rollback:
if (partial && result == ISC_R_NOSPACE) {
INSIST(rrbuffer.used < 65536);
dns_compress_rollback(cctx, (isc_uint16_t)rrbuffer.used);
*countp += added;
*target = rrbuffer;
goto cleanup;
}
INSIST(savedbuffer.used < 65536);
dns_compress_rollback(cctx, (isc_uint16_t)savedbuffer.used);
*countp = 0;
*target = savedbuffer;
cleanup:
if (sorted != NULL && sorted != sorted_fixed)
isc_mem_put(cctx->mctx, sorted, count * sizeof(*sorted));
if (shuffled != NULL && shuffled != shuffled_fixed)
isc_mem_put(cctx->mctx, shuffled, count * sizeof(*shuffled));
return (result);
}
