2162. [func] Allow "rrset-order fixed" to be disabled at compile

                        time. [RT #16665]
: ----------------------------------------------------------------------

diff --git a/CHANGES b/CHANGES
index 8a5b1475e8d941368310b100ee46f0a1557bb07c..e9fed1d22695c5f922cacad654ee946a72266a97 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+2162.  [func]          Allow "rrset-order fixed" to be disabled at compile
+                       time. [RT #16665]
+
 2161.  [bug]           Fix which log messages are emitted for 'rndc flush'.
                        [RT #16698]
 

diff --git a/README b/README
index 33c95aed2afe1ac3ebc4fd03a05e5ed50f670961..a73db9644342fa7ae279ec5eb0d00d6c864763e0 100644 (file)
--- a/README
+++ b/README
@@ -362,7 +362,7 @@ Building
        We've had successful builds and tests on the following systems:
 
                COMPAQ Tru64 UNIX 5.1B
-               FreeBSD 4.10, 5.2.1
+               FreeBSD 4.10, 5.2.1, 6.2
                HP-UX 11.11
                NetBSD 1.5
                Slackware Linux 8.1
@@ -419,6 +419,8 @@ Building
                                    -DDIG_SIGCHASE_BU=1)
                Disable dropping queries from particular well known ports.
                  -DNS_CLIENT_DROPPORT=0
+               Disable support for "rrset-order fixed".
+                 -DDNS_RDATASET_FIXED=0
 
            LDFLAGS
                Linker flags. Defaults to empty string.

diff --git a/lib/bind9/check.c b/lib/bind9/check.c
index 653eeb0cfda6710c538357391183943318deec39..87d737d30b3077e2c2e5367fa284c37e00819c56 100644 (file)
--- a/lib/bind9/check.c
+++ b/lib/bind9/check.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: check.c,v 1.76 2006/08/21 00:11:43 marka Exp $ */
+/* $Id: check.c,v 1.77 2007/03/14 05:57:10 marka Exp $ */
 
 /*! \file */
 
@@ -46,6 +46,10 @@
 
 #include <bind9/check.h>
 
+#ifndef DNS_RDATASET_FIXED
+#define DNS_RDATASET_FIXED 1
+#endif
+
 static void
 freekey(char *key, unsigned int type, isc_symvalue_t value, void *userarg) {
        UNUSED(type);
@@ -121,8 +125,12 @@ check_orderent(const cfg_obj_t *ent, isc_log_t *logctx) {
            cfg_obj_log(ent, logctx, ISC_LOG_ERROR,
                        "rrset-order: missing ordering");
                result = ISC_R_FAILURE;
-       } else if (strcasecmp(cfg_obj_asstring(obj), "fixed") != 0 &&
-                  strcasecmp(cfg_obj_asstring(obj), "random") != 0 &&
+       } else if (strcasecmp(cfg_obj_asstring(obj), "fixed") == 0) {
+#if !DNS_RDATASET_FIXED
+               cfg_obj_log(obj, logctx, ISC_LOG_WARNING,
+                           "rrset-order: order 'fixed' not fully implemented");
+#endif
+       } else if (strcasecmp(cfg_obj_asstring(obj), "random") != 0 &&
                   strcasecmp(cfg_obj_asstring(obj), "cyclic") != 0) {
                cfg_obj_log(obj, logctx, ISC_LOG_ERROR,
                            "rrset-order: invalid order '%s'",

diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index afef0e18ae24c9bddd0fa26d58e289b021471ea4..a6809ecb70f54744333e8f31828eaca1a7abbb7d 100644 (file)
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: rbtdb.c,v 1.243 2007/03/12 03:37:21 marka Exp $ */
+/* $Id: rbtdb.c,v 1.244 2007/03/14 05:57:10 marka Exp $ */
 
 /*! \file */
 
@@ -179,6 +179,10 @@ typedef isc_mutex_t nodelock_t;
 #define NODE_WEAKDOWNGRADE(l)  ((void)0)
 #endif
 
+#ifndef DNS_RDATASET_FIXED
+#define DNS_RDATASET_FIXED 1
+#endif
+
 /*
  * Allow clients with a virtual time of upto 5 minutes in the past to see
  * records that would have otherwise have expired.
@@ -1977,12 +1981,20 @@ valid_glue(rbtdb_search_t *search, dns_name_t *name, rbtdb_rdatatype_t type,
        header = search->zonecut_rdataset;
        raw = (unsigned char *)header + sizeof(*header);
        count = raw[0] * 256 + raw[1];
+#if DNS_RDATASET_FIXED
        raw += 2 + (4 * count);
+#else 
+       raw += 2;
+#endif
 
        while (count > 0) {
                count--;
                size = raw[0] * 256 + raw[1];
+#if DNS_RDATASET_FIXED
                raw += 4;
+#else
+               raw += 2;
+#endif
                region.base = raw;
                region.length = size;
                raw += size;
@@ -5651,9 +5663,11 @@ rdataset_first(dns_rdataset_t *rdataset) {
                return (ISC_R_NOMORE);
        }
        
+#if DNS_RDATASET_FIXED
        if ((rdataset->attributes & DNS_RDATASETATTR_LOADORDER) == 0)
                raw += 2 + (4 * count);
        else
+#endif
                raw += 2;
 
        /*
@@ -5688,11 +5702,17 @@ rdataset_next(dns_rdataset_t *rdataset) {
         * Skip forward one record (length + 4) or one offset (4).
         */
        raw = rdataset->private5;
+#if DNS_RDATASET_FIXED
        if ((rdataset->attributes & DNS_RDATASETATTR_LOADORDER) == 0) {
+#endif
                length = raw[0] * 256 + raw[1];
                raw += length;
+#if DNS_RDATASET_FIXED
        }
-       rdataset->private5 = raw + 4;
+       rdataset->private5 = raw + 4;           /* length(2) + order(2) */
+#else
+       rdataset->private5 = raw + 2;           /* length(2) */
+#endif
 
        return (ISC_R_SUCCESS);
 }
@@ -5700,7 +5720,9 @@ rdataset_next(dns_rdataset_t *rdataset) {
 static void
 rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
        unsigned char *raw = rdataset->private5;        /* RDATASLAB */
+#if DNS_RDATASET_FIXED
        unsigned int offset;
+#endif
        isc_region_t r;
 
        REQUIRE(raw != NULL);
@@ -5709,14 +5731,21 @@ rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
         * Find the start of the record if not already in private5
         * then skip the length and order fields.
         */
+#if DNS_RDATASET_FIXED
        if ((rdataset->attributes & DNS_RDATASETATTR_LOADORDER) != 0) {
                offset = (raw[0] << 24) + (raw[1] << 16) +
                         (raw[2] << 8) + raw[3];
                raw = rdataset->private3;
                raw += offset;
        }
+#endif
        r.length = raw[0] * 256 + raw[1];
+
+#if DNS_RDATASET_FIXED
        raw += 4;
+#else
+       raw += 2;
+#endif
        r.base = raw;
        dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r);
 }

diff --git a/lib/dns/rdataslab.c b/lib/dns/rdataslab.c
index 4b50602c03ca6fc214052814c97204b892c22a2a..78943e53b08bb781ddbc117ade3366b37d37e434 100644 (file)
--- a/lib/dns/rdataslab.c
+++ b/lib/dns/rdataslab.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: rdataslab.c,v 1.40 2006/03/05 23:58:52 marka Exp $ */
+/* $Id: rdataslab.c,v 1.41 2007/03/14 05:57:10 marka Exp $ */
 
 /*! \file */
 
@@ -33,6 +33,10 @@
 #include <dns/rdataset.h>
 #include <dns/rdataslab.h>
 
+#ifndef DNS_RDATASET_FIXED
+#define DNS_RDATASET_FIXED 1
+#endif
+
 /*
  * The rdataslab structure allows iteration to occur in both load order
  * and DNSSEC order.  The structure is as follows:
@@ -45,10 +49,19 @@
  *             order           (2 bytes)
  *             data            (data length bytes)
  *
+ * If DNS_RDATASET_FIXED is defined to be zero (0) the format of a
+ * rdataslab is as follows:
+ *
+ *     header          (reservelen bytes)
+ *     record count    (2 bytes)
+ *     data records
+ *             data length     (2 bytes)
+ *             data            (data length bytes)
+ *
  * Offsets are from the end of the header.
  *
  * Load order traversal is performed by walking the offset table to find
- * the start of the record.
+ * the start of the record (DNS_RDATASET_FIXED = 1).
  *
  * DNSSEC order traversal is performed by walking the data records.
  *
@@ -79,6 +92,7 @@ compare_rdata(const void *p1, const void *p2) {
        return (dns_rdata_compare(&x1->rdata, &x2->rdata));
 }
 
+#if DNS_RDATASET_FIXED
 static void
 fillin_offsets(unsigned char *offsetbase, unsigned int *offsettable,
               unsigned length)
@@ -108,6 +122,7 @@ fillin_offsets(unsigned char *offsetbase, unsigned int *offsettable,
                *raw = j++ & 0xff;
        }
 }
+#endif
 
 isc_result_t
 dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
@@ -115,13 +130,17 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
 {
        struct xrdata  *x;
        unsigned char  *rawbuf;
+#if DNS_RDATASET_FIXED
        unsigned char  *offsetbase;
+#endif
        unsigned int    buflen;
        isc_result_t    result;
        unsigned int    nitems;
        unsigned int    nalloc;
        unsigned int    i;
+#if DNS_RDATASET_FIXED
        unsigned int   *offsettable;
+#endif
 
        buflen = reservelen + 2;
 
@@ -147,7 +166,9 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
                INSIST(result == ISC_R_SUCCESS);
                dns_rdata_init(&x[i].rdata);
                dns_rdataset_current(rdataset, &x[i].rdata);
+#if DNS_RDATASET_FIXED
                x[i].order = i;
+#endif
                result = dns_rdataset_next(rdataset);
        }
        if (result != ISC_R_NOMORE)
@@ -179,20 +200,30 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
                if (compare_rdata(&x[i-1].rdata, &x[i].rdata) == 0) {
                        x[i-1].rdata.data = NULL;
                        x[i-1].rdata.length = 0;
+#if DNS_RDATASET_FIXED
                        /*
                         * Preserve the least order so A, B, A -> A, B
                         * after duplicate removal.
                         */
                        if (x[i-1].order < x[i].order)
                                x[i].order = x[i-1].order;
+#endif
                        nitems--;
                } else
+#if DNS_RDATASET_FIXED
                        buflen += (8 + x[i-1].rdata.length);
+#else
+                       buflen += (2 + x[i-1].rdata.length);
+#endif
        }
        /*
         * Don't forget the last item!
         */
+#if DNS_RDATASET_FIXED
        buflen += (8 + x[i-1].rdata.length);
+#else
+       buflen += (2 + x[i-1].rdata.length);
+#endif
 
        /*
         * Ensure that singleton types are actually singletons.
@@ -216,6 +247,7 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
                goto free_rdatas;
        }
        
+#if DNS_RDATASET_FIXED
        /* Allocate temporary offset table. */
        offsettable = isc_mem_get(mctx, nalloc * sizeof(unsigned int));
        if (offsettable == NULL) {
@@ -224,33 +256,43 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
                goto free_rdatas;
        }
        memset(offsettable, 0, nalloc * sizeof(unsigned int));
+#endif
 
        region->base = rawbuf;
        region->length = buflen;
 
        rawbuf += reservelen;
+#if DNS_RDATASET_FIXED
        offsetbase = rawbuf;
+#endif
 
        *rawbuf++ = (nitems & 0xff00) >> 8;
        *rawbuf++ = (nitems & 0x00ff);
 
+#if DNS_RDATASET_FIXED
        /* Skip load order table.  Filled in later. */
        rawbuf += nitems * 4;
+#endif
 
        for (i = 0; i < nalloc; i++) {
                if (x[i].rdata.data == NULL)
                        continue;
+#if DNS_RDATASET_FIXED
                offsettable[x[i].order] = rawbuf - offsetbase;
+#endif
                *rawbuf++ = (x[i].rdata.length & 0xff00) >> 8;
                *rawbuf++ = (x[i].rdata.length & 0x00ff);
+#if DNS_RDATASET_FIXED
                rawbuf += 2;    /* filled in later */
+#endif
                memcpy(rawbuf, x[i].rdata.data, x[i].rdata.length);
                rawbuf += x[i].rdata.length;
        }
        
+#if DNS_RDATASET_FIXED
        fillin_offsets(offsetbase, offsettable, nalloc);
-
        isc_mem_put(mctx, offsettable, nalloc * sizeof(unsigned int));
+#endif
 
        result = ISC_R_SUCCESS;
 
@@ -274,7 +316,11 @@ rdataset_first(dns_rdataset_t *rdataset) {
                rdataset->private5 = NULL;
                return (ISC_R_NOMORE);
        }
+#if DNS_RDATASET_FIXED
        raw += 2 + (4 * count);
+#else
+       raw += 2;
+#endif
        /*
         * The privateuint4 field is the number of rdata beyond the cursor
         * position, so we decrement the total count by one before storing
@@ -300,7 +346,11 @@ rdataset_next(dns_rdataset_t *rdataset) {
        rdataset->privateuint4 = count;
        raw = rdataset->private5;
        length = raw[0] * 256 + raw[1];
+#if DNS_RDATASET_FIXED
        raw += length + 4;
+#else
+       raw += length + 2;
+#endif
        rdataset->private5 = raw;
 
        return (ISC_R_SUCCESS);
@@ -314,7 +364,11 @@ rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
        REQUIRE(raw != NULL);
 
        r.length = raw[0] * 256 + raw[1];
+#if DNS_RDATASET_FIXED
        raw += 4;
+#else
+       raw += 2;
+#endif 
        r.base = raw;
        dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r);
 }
@@ -390,12 +444,18 @@ dns_rdataslab_size(unsigned char *slab, unsigned int reservelen) {
        current = slab + reservelen;
        count = *current++ * 256;
        count += *current++;
+#if DNS_RDATASET_FIXED
        current += (4 * count);
+#endif
        while (count > 0) {
                count--;
                length = *current++ * 256;
                length += *current++;
+#if DNS_RDATASET_FIXED
                current += length + 2;
+#else
+               current += length;
+#endif
        }
 
        return ((unsigned int)(current - slab));
@@ -417,7 +477,9 @@ rdata_from_slab(unsigned char **current,
 
        region.length = *tcurrent++ * 256;
        region.length += *tcurrent++;
+#if DNS_RDATASET_FIXED
        tcurrent += 2;
+#endif
        region.base = tcurrent;
        tcurrent += region.length;
        dns_rdata_fromregion(rdata, rdclass, type, &region);
@@ -443,7 +505,9 @@ rdata_in_slab(unsigned char *slab, unsigned int reservelen,
        count = *current++ * 256;
        count += *current++;
 
+#if DNS_RDATASET_FIXED
        current += (4 * count);
+#endif
 
        for (i = 0; i < count; i++) {
                rdata_from_slab(&current, rdclass, type, &trdata);
@@ -473,11 +537,13 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
        unsigned int oadded = 0;
        unsigned int nadded = 0;
        unsigned int nncount = 0;
+#if DNS_RDATASET_FIXED
        unsigned int oncount;
        unsigned int norder = 0;
        unsigned int oorder = 0;
        unsigned char *offsetbase;
        unsigned int *offsettable;
+#endif
 
        /*
         * XXX  Need parameter to allow "delete rdatasets in nslab" merge,
@@ -490,15 +556,21 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
        ocurrent = oslab + reservelen;
        ocount = *ocurrent++ * 256;
        ocount += *ocurrent++;
+#if DNS_RDATASET_FIXED
        ocurrent += (4 * ocount);
+#endif
        ostart = ocurrent;
        ncurrent = nslab + reservelen;
        ncount = *ncurrent++ * 256;
        ncount += *ncurrent++;
+#if DNS_RDATASET_FIXED
        ncurrent += (4 * ncount);
+#endif
        INSIST(ocount > 0 && ncount > 0);
 
+#if DNS_RDATASET_FIXED
        oncount = ncount;
+#endif
 
        /*
         * Yes, this is inefficient!
@@ -511,8 +583,13 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
        for (count = 0; count < ocount; count++) {
                length = *ocurrent++ * 256;
                length += *ocurrent++;
+#if DNS_RDATASET_FIXED
                olength += length + 8;
                ocurrent += length + 2;
+#else
+               olength += length + 2;
+               ocurrent += length;
+#endif
        }
 
        /*
@@ -528,7 +605,9 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
        do {
                nregion.length = *ncurrent++ * 256;
                nregion.length += *ncurrent++;
-               ncurrent += 2;
+#if DNS_RDATASET_FIXED
+               ncurrent += 2;                  /* Skip order. */
+#endif
                nregion.base = ncurrent;
                dns_rdata_init(&nrdata);
                dns_rdata_fromregion(&nrdata, rdclass, type, &nregion);
@@ -537,7 +616,11 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
                        /*
                         * This rdata isn't in the old slab.
                         */
+#if DNS_RDATASET_FIXED
                        tlength += nregion.length + 8;
+#else
+                       tlength += nregion.length + 2;
+#endif
                        tcount++;
                        nncount++;
                        added_something = ISC_TRUE;
@@ -576,7 +659,9 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
                return (ISC_R_NOMEMORY);
        memcpy(tstart, nslab, reservelen);
        tcurrent = tstart + reservelen;
+#if DNS_RDATASET_FIXED
        offsetbase = tcurrent;
+#endif
 
        /*
         * Write the new count.
@@ -584,6 +669,7 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
        *tcurrent++ = (tcount & 0xff00) >> 8;
        *tcurrent++ = (tcount & 0x00ff);
 
+#if DNS_RDATASET_FIXED
        /*
         * Skip offset table.
         */
@@ -596,25 +682,33 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
                return (ISC_R_NOMEMORY);
        }
        memset(offsettable, 0, (ocount + oncount) * sizeof(unsigned int));
+#endif
 
        /*
         * Merge the two slabs.
         */
        ocurrent = ostart;
        INSIST(ocount != 0);
+#if DNS_RDATASET_FIXED
        oorder = ocurrent[2] * 256 + ocurrent[3];
        INSIST(oorder < ocount);
+#endif
        rdata_from_slab(&ocurrent, rdclass, type, &ordata);
 
        ncurrent = nslab + reservelen + 2;
+#if DNS_RDATASET_FIXED
        ncurrent += (4 * oncount);
+#endif
 
        if (ncount > 0) {
                do {
                        dns_rdata_reset(&nrdata);
+#if DNS_RDATASET_FIXED
                        norder = ncurrent[2] * 256 + ncurrent[3];
+
                        INSIST(norder < oncount);
-                               rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
+#endif
+                       rdata_from_slab(&ncurrent, rdclass, type, &nrdata);
                } while (rdata_in_slab(oslab, reservelen, rdclass,
                                       type, &nrdata));
        }
@@ -628,36 +722,48 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
                else
                        fromold = ISC_TF(compare_rdata(&ordata, &nrdata) < 0);
                if (fromold) {
+#if DNS_RDATASET_FIXED
                        offsettable[oorder] = tcurrent - offsetbase;
+#endif
                        length = ordata.length;
                        *tcurrent++ = (length & 0xff00) >> 8;
                        *tcurrent++ = (length & 0x00ff);
+#if DNS_RDATASET_FIXED
                        tcurrent += 2;  /* fill in later */
+#endif
                        memcpy(tcurrent, ordata.data, length);
                        tcurrent += length;
                        oadded++;
                        if (oadded < ocount) {
                                dns_rdata_reset(&ordata);
+#if DNS_RDATASET_FIXED
                                oorder = ocurrent[2] * 256 + ocurrent[3];
                                INSIST(oorder < ocount);
-                                       rdata_from_slab(&ocurrent, rdclass, type,
+#endif
+                               rdata_from_slab(&ocurrent, rdclass, type,
                                                &ordata);
                        }
                } else {
+#if DNS_RDATASET_FIXED
                        offsettable[ocount + norder] = tcurrent - offsetbase;
+#endif
                        length = nrdata.length;
                        *tcurrent++ = (length & 0xff00) >> 8;
                        *tcurrent++ = (length & 0x00ff);
+#if DNS_RDATASET_FIXED
                        tcurrent += 2;  /* fill in later */
+#endif
                        memcpy(tcurrent, nrdata.data, length);
                        tcurrent += length;
                        nadded++;
                        if (nadded < ncount) {
                                do {
                                        dns_rdata_reset(&nrdata);
+#if DNS_RDATASET_FIXED
                                        norder = ncurrent[2] * 256 + ncurrent[3];
                                        INSIST(norder < oncount);
-                                               rdata_from_slab(&ncurrent, rdclass,
+#endif
+                                       rdata_from_slab(&ncurrent, rdclass,
                                                        type, &nrdata);
                                } while (rdata_in_slab(oslab, reservelen,
                                                       rdclass, type,
@@ -666,10 +772,12 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
                }
        }
 
+#if DNS_RDATASET_FIXED
        fillin_offsets(offsetbase, offsettable, ocount + oncount);
 
        isc_mem_put(mctx, offsettable,
                    (ocount + oncount) * sizeof(unsigned int));
+#endif
 
        INSIST(tcurrent == tstart + tlength);
 
@@ -688,8 +796,10 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
        unsigned int mcount, scount, rcount ,count, tlength, tcount, i;
        dns_rdata_t srdata = DNS_RDATA_INIT;
        dns_rdata_t mrdata = DNS_RDATA_INIT;
+#if DNS_RDATASET_FIXED
        unsigned char *offsetbase;
        unsigned int *offsettable;
+#endif
        unsigned int order;
 
        REQUIRE(tslabp != NULL && *tslabp == NULL);
@@ -714,8 +824,10 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
        tcount = 0;
        rcount = 0;
 
+#if DNS_RDATASET_FIXED
        mcurrent += 4 * mcount;
        scurrent += 4 * scount;
+#endif
        sstart = scurrent;
 
        /*
@@ -744,11 +856,13 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
                dns_rdata_reset(&mrdata);
        }
 
+#if DNS_RDATASET_FIXED
        tlength += (4 * tcount);
+#endif
 
        /*
         * Check that all the records originally existed.  The numeric
-        * check only works as rdataslabs do not contain duplicates.
+        * check only works as rdataslabs do not contain duplicates.
         */
        if (((flags & DNS_RDATASLAB_EXACT) != 0) && (rcount != scount))
                return (DNS_R_NOTEXACT);
@@ -773,6 +887,7 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
                return (ISC_R_NOMEMORY);
        memcpy(tstart, mslab, reservelen);
        tcurrent = tstart + reservelen;
+#if DNS_RDATASET_FIXED
        offsetbase = tcurrent;
 
        offsettable = isc_mem_get(mctx, mcount * sizeof(unsigned int));
@@ -781,6 +896,7 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
                return (ISC_R_NOMEMORY);
        }
        memset(offsettable, 0, mcount * sizeof(unsigned int));
+#endif
 
        /*
         * Write the new count.
@@ -788,7 +904,9 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
        *tcurrent++ = (tcount & 0xff00) >> 8;
        *tcurrent++ = (tcount & 0x00ff);
 
+#if DNS_RDATASET_FIXED
        tcurrent += (4 * tcount);
+#endif
 
        /*
         * Copy the parts of mslab not in sslab.
@@ -796,11 +914,15 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
        mcurrent = mslab + reservelen;
        mcount = *mcurrent++ * 256;
        mcount += *mcurrent++;
+#if DNS_RDATASET_FIXED
        mcurrent += (4 * mcount);
+#endif
        for (i = 0; i < mcount; i++) {
                unsigned char *mrdatabegin = mcurrent;
+#if DNS_RDATASET_FIXED
                order = mcurrent[2] * 256 + mcurrent[3];
                INSIST(order < mcount);
+#endif
                rdata_from_slab(&mcurrent, rdclass, type, &mrdata);
                scurrent = sstart;
                for (count = 0; count < scount; count++) {
@@ -815,16 +937,20 @@ dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab,
                         * copied to the tslab.
                         */
                        unsigned int length = mcurrent - mrdatabegin;
+#if DNS_RDATASET_FIXED
                        offsettable[order] = tcurrent - offsetbase;
+#endif
                        memcpy(tcurrent, mrdatabegin, length);
                        tcurrent += length;
                }
                dns_rdata_reset(&mrdata);
        }
 
+#if DNS_RDATASET_FIXED
        fillin_offsets(offsetbase, offsettable, mcount);
 
        isc_mem_put(mctx, offsettable, mcount * sizeof(unsigned int));
+#endif
 
        INSIST(tcurrent == tstart + tlength);
 
@@ -852,8 +978,10 @@ dns_rdataslab_equal(unsigned char *slab1, unsigned char *slab2,
        if (count1 != count2)
                return (ISC_FALSE);
 
+#if DNS_RDATASET_FIXED
        current1 += (4 * count1);
        current2 += (4 * count2);
+#endif
 
        while (count1 > 0) {
                length1 = *current1++ * 256;
@@ -862,8 +990,10 @@ dns_rdataslab_equal(unsigned char *slab1, unsigned char *slab2,
                length2 = *current2++ * 256;
                length2 += *current2++;
 
+#if DNS_RDATASET_FIXED
                current1 += 2;
                current2 += 2;
+#endif
 
                if (length1 != length2 ||
                    memcmp(current1, current2, length1) != 0)
@@ -898,8 +1028,10 @@ dns_rdataslab_equalx(unsigned char *slab1, unsigned char *slab2,
        if (count1 != count2)
                return (ISC_FALSE);
 
+#if DNS_RDATASET_FIXED
        current1 += (4 * count1);
        current2 += (4 * count2);
+#endif
 
        while (count1-- > 0) {
                rdata_from_slab(&current1, rdclass, type, &rdata1);