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Implement rrset ordering. Default is cyclic.

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If the rdataset iterator failed unexpectedly while rendering, we failed to
rollback.
This commit is contained in:
Bob Halley
2000-02-24 21:08:34 +00:00
parent b91bbbcdb4
commit c3b708aaf1
1 changed files with 84 additions and 8 deletions
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92
lib/dns/rdataset.c
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@@ -18,6 +18,7 @@
#include <config.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <isc/assertions.h>
@@ -251,6 +252,11 @@ dns_rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
(rdataset->methods->current)(rdataset, rdata);
}
#define MAX_SHUFFLE 32
#define WANT_FIXED(r) (((r)->attributes & DNS_RDATASETATTR_FIXEDORDER) != 0)
#define WANT_RANDOM(r) (((r)->attributes & DNS_RDATASETATTR_RANDOMIZE) != 0)
isc_result_t
dns_rdataset_towire(dns_rdataset_t *rdataset,
dns_name_t *owner_name,
@@ -261,10 +267,12 @@ dns_rdataset_towire(dns_rdataset_t *rdataset,
dns_rdata_t rdata;
isc_region_t r;
isc_result_t result;
unsigned int count;
unsigned int i, count, tcount, choice;
isc_buffer_t savedbuffer, rdlen;
unsigned int headlen;
isc_boolean_t question = ISC_FALSE;
isc_boolean_t shuffle = ISC_FALSE;
dns_rdata_t shuffled[MAX_SHUFFLE];
/*
* Convert 'rdataset' to wire format, compressing names as specified
@@ -274,8 +282,10 @@ dns_rdataset_towire(dns_rdataset_t *rdataset,
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(countp != NULL);
count = 0;
if ((rdataset->attributes & DNS_RDATASETATTR_QUESTION) != 0) {
question = ISC_TRUE;
count = 1;
result = dns_rdataset_first(rdataset);
INSIST(result == DNS_R_NOMORE);
} else if (rdataset->type == 0) {
@@ -284,6 +294,7 @@ dns_rdataset_towire(dns_rdataset_t *rdataset,
*/
return (dns_ncache_towire(rdataset, cctx, target, countp));
} else {
count = (rdataset->methods->count)(rdataset);
result = dns_rdataset_first(rdataset);
if (result == DNS_R_NOMORE)
return (DNS_R_SUCCESS);
@@ -291,9 +302,60 @@ dns_rdataset_towire(dns_rdataset_t *rdataset,
return (result);
}
savedbuffer = *target;
choice = 0;
if (!question && count > 1 && !WANT_FIXED(rdataset)) {
/*
* We'll only shuffle if we've got enough slots in our
* deck.
*
* There's no point to shuffling SIGs.
*/
if (count <= MAX_SHUFFLE &&
rdataset->type != dns_rdatatype_sig) {
shuffle = ISC_TRUE;
/*
* First we get handles to all of the rdata.
*/
i = 0;
do {
INSIST(i < count);
dns_rdataset_current(rdataset, &shuffled[i]);
i++;
result = dns_rdataset_next(rdataset);
} while (result == ISC_R_SUCCESS);
if (result != DNS_R_NOMORE)
return (result);
INSIST(i == count);
/*
* Now we shuffle.
*/
if (WANT_RANDOM(rdataset)) {
/*
* "Random" order.
*/
tcount = count;
for (i = 0; i < count; i++) {
choice = (((unsigned int)rand()) >> 3)
% tcount;
rdata = shuffled[i];
shuffled[i] = shuffled[i + choice];
shuffled[i + choice] = rdata;
tcount--;
}
choice = 0;
} else {
/*
* "Cyclic" order.
*/
choice = (((unsigned int)rand()) >> 3) % count;
}
}
}
savedbuffer = *target;
i = choice;
tcount = 0;
count = 0;
do {
/*
* copy out the name, type, class, ttl.
@@ -328,7 +390,10 @@ dns_rdataset_towire(dns_rdataset_t *rdataset,
/*
* copy out the rdata
*/
dns_rdataset_current(rdataset, &rdata);
if (shuffle)
rdata = shuffled[i];
else
dns_rdataset_current(rdataset, &rdata);
result = dns_compress_localinit(cctx, owner_name,
target);
if (result != DNS_R_SUCCESS)
@@ -344,13 +409,24 @@ dns_rdataset_towire(dns_rdataset_t *rdataset,
rdlen.used - 2));
}
count++;
result = dns_rdataset_next(rdataset);
if (shuffle) {
i++;
/*
* Wrap around in case we're doing cyclic ordering.
*/
if (i == count)
i = 0;
tcount++;
if (tcount == count)
result = DNS_R_NOMORE;
else
result = ISC_R_SUCCESS;
} else
result = dns_rdataset_next(rdataset);
} while (result == DNS_R_SUCCESS);
if (result != DNS_R_NOMORE)
return (result);
goto rollback;
*countp += count;