diff options
Diffstat (limited to 'lib/dns/rdataslab.c')
| -rw-r--r-- | lib/dns/rdataslab.c | 1092 |
1 files changed, 1092 insertions, 0 deletions
diff --git a/lib/dns/rdataslab.c b/lib/dns/rdataslab.c new file mode 100644 index 0000000..610d44f --- /dev/null +++ b/lib/dns/rdataslab.c @@ -0,0 +1,1092 @@ +/* + * Copyright (C) 2004-2008 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1999-2003 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: rdataslab.c,v 1.48 2008/09/24 02:46:22 marka Exp $ */ + +/*! \file */ + +#include <config.h> + +#include <stdlib.h> + +#include <isc/mem.h> +#include <isc/region.h> +#include <isc/string.h> /* Required for HP/UX (and others?) */ +#include <isc/util.h> + +#include <dns/result.h> +#include <dns/rdata.h> +#include <dns/rdataset.h> +#include <dns/rdataslab.h> + +/* + * The rdataslab structure allows iteration to occur in both load order + * and DNSSEC order. The structure is as follows: + * + * header (reservelen bytes) + * record count (2 bytes) + * offset table (4 x record count bytes in load order) + * data records + * data length (2 bytes) + * order (2 bytes) + * meta data (1 byte for RRSIG's) + * 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 (DNS_RDATASET_FIXED = 1). + * + * DNSSEC order traversal is performed by walking the data records. + * + * The order is stored with record to allow for efficient reconstuction of + * of the offset table following a merge or subtraction. + * + * The iterator methods here currently only support DNSSEC order iteration. + * + * The iterator methods in rbtdb support both load order and DNSSEC order + * iteration. + * + * WARNING: + * rbtdb.c directly interacts with the slab's raw structures. If the + * structure changes then rbtdb.c also needs to be updated to reflect + * the changes. See the areas tagged with "RDATASLAB". + */ + +struct xrdata { + dns_rdata_t rdata; + unsigned int order; +}; + +/*% Note: the "const void *" are just to make qsort happy. */ +static int +compare_rdata(const void *p1, const void *p2) { + const struct xrdata *x1 = p1; + const struct xrdata *x2 = 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) +{ + unsigned int i, j; + unsigned char *raw; + + for (i = 0, j = 0; i < length; i++) { + + if (offsettable[i] == 0) + continue; + + /* + * Fill in offset table. + */ + raw = &offsetbase[j*4 + 2]; + *raw++ = (offsettable[i] & 0xff000000) >> 24; + *raw++ = (offsettable[i] & 0xff0000) >> 16; + *raw++ = (offsettable[i] & 0xff00) >> 8; + *raw = offsettable[i] & 0xff; + + /* + * Fill in table index. + */ + raw = offsetbase + offsettable[i] + 2; + *raw++ = (j & 0xff00) >> 8; + *raw = j++ & 0xff; + } +} +#endif + +isc_result_t +dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx, + isc_region_t *region, unsigned int reservelen) +{ + 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 + unsigned int length; + + buflen = reservelen + 2; + + nalloc = dns_rdataset_count(rdataset); + nitems = nalloc; + if (nitems == 0) + return (ISC_R_FAILURE); + + if (nalloc > 0xffff) + return (ISC_R_NOSPACE); + + x = isc_mem_get(mctx, nalloc * sizeof(struct xrdata)); + if (x == NULL) + return (ISC_R_NOMEMORY); + + /* + * Save all of the rdata members into an array. + */ + result = dns_rdataset_first(rdataset); + if (result != ISC_R_SUCCESS) + goto free_rdatas; + for (i = 0; i < nalloc && result == ISC_R_SUCCESS; i++) { + 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) + goto free_rdatas; + if (i != nalloc) { + /* + * Somehow we iterated over fewer rdatas than + * dns_rdataset_count() said there were! + */ + result = ISC_R_FAILURE; + goto free_rdatas; + } + + /* + * Put into DNSSEC order. + */ + qsort(x, nalloc, sizeof(struct xrdata), compare_rdata); + + /* + * Remove duplicates and compute the total storage required. + * + * If an rdata is not a duplicate, accumulate the storage size + * required for the rdata. We do not store the class, type, etc, + * just the rdata, so our overhead is 2 bytes for the number of + * records, and 8 for each rdata, (length(2), offset(4) and order(2)) + * and then the rdata itself. + */ + for (i = 1; i < nalloc; i++) { + 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 + /* + * Provide space to store the per RR meta data. + */ + if (rdataset->type == dns_rdatatype_rrsig) + buflen++; + } + } + /* + * 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 + /* + * Provide space to store the per RR meta data. + */ + if (rdataset->type == dns_rdatatype_rrsig) + buflen++; + + /* + * Ensure that singleton types are actually singletons. + */ + if (nitems > 1 && dns_rdatatype_issingleton(rdataset->type)) { + /* + * We have a singleton type, but there's more than one + * RR in the rdataset. + */ + result = DNS_R_SINGLETON; + goto free_rdatas; + } + + /* + * Allocate the memory, set up a buffer, start copying in + * data. + */ + rawbuf = isc_mem_get(mctx, buflen); + if (rawbuf == NULL) { + result = ISC_R_NOMEMORY; + goto free_rdatas; + } + +#if DNS_RDATASET_FIXED + /* Allocate temporary offset table. */ + offsettable = isc_mem_get(mctx, nalloc * sizeof(unsigned int)); + if (offsettable == NULL) { + isc_mem_put(mctx, rawbuf, buflen); + result = ISC_R_NOMEMORY; + 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 + length = x[i].rdata.length; + if (rdataset->type == dns_rdatatype_rrsig) + length++; + *rawbuf++ = (length & 0xff00) >> 8; + *rawbuf++ = (length & 0x00ff); +#if DNS_RDATASET_FIXED + rawbuf += 2; /* filled in later */ +#endif + /* + * Store the per RR meta data. + */ + if (rdataset->type == dns_rdatatype_rrsig) { + *rawbuf++ |= (x[i].rdata.flags & DNS_RDATA_OFFLINE) ? + DNS_RDATASLAB_OFFLINE : 0; + } + 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; + + free_rdatas: + isc_mem_put(mctx, x, nalloc * sizeof(struct xrdata)); + return (result); +} + +static void +rdataset_disassociate(dns_rdataset_t *rdataset) { + UNUSED(rdataset); +} + +static isc_result_t +rdataset_first(dns_rdataset_t *rdataset) { + unsigned char *raw = rdataset->private3; + unsigned int count; + + count = raw[0] * 256 + raw[1]; + if (count == 0) { + 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 + * it. + */ + count--; + rdataset->privateuint4 = count; + rdataset->private5 = raw; + + return (ISC_R_SUCCESS); +} + +static isc_result_t +rdataset_next(dns_rdataset_t *rdataset) { + unsigned int count; + unsigned int length; + unsigned char *raw; + + count = rdataset->privateuint4; + if (count == 0) + return (ISC_R_NOMORE); + count--; + 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); +} + +static void +rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) { + unsigned char *raw = rdataset->private5; + isc_region_t r; + unsigned int length; + unsigned int flags = 0; + + REQUIRE(raw != NULL); + + length = raw[0] * 256 + raw[1]; +#if DNS_RDATASET_FIXED + raw += 4; +#else + raw += 2; +#endif + if (rdataset->type == dns_rdatatype_rrsig) { + if (*raw & DNS_RDATASLAB_OFFLINE) + flags |= DNS_RDATA_OFFLINE; + length--; + raw++; + } + r.length = length; + r.base = raw; + dns_rdata_fromregion(rdata, rdataset->rdclass, rdataset->type, &r); + rdata->flags |= flags; +} + +static void +rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) { + *target = *source; + + /* + * Reset iterator state. + */ + target->privateuint4 = 0; + target->private5 = NULL; +} + +static unsigned int +rdataset_count(dns_rdataset_t *rdataset) { + unsigned char *raw = rdataset->private3; + unsigned int count; + + count = raw[0] * 256 + raw[1]; + + return (count); +} + +static dns_rdatasetmethods_t rdataset_methods = { + rdataset_disassociate, + rdataset_first, + rdataset_next, + rdataset_current, + rdataset_clone, + rdataset_count, + NULL, + NULL, + NULL, + NULL, + NULL, + NULL, + NULL +}; + +void +dns_rdataslab_tordataset(unsigned char *slab, unsigned int reservelen, + dns_rdataclass_t rdclass, dns_rdatatype_t rdtype, + dns_rdatatype_t covers, dns_ttl_t ttl, + dns_rdataset_t *rdataset) +{ + REQUIRE(slab != NULL); + REQUIRE(!dns_rdataset_isassociated(rdataset)); + + rdataset->methods = &rdataset_methods; + rdataset->rdclass = rdclass; + rdataset->type = rdtype; + rdataset->covers = covers; + rdataset->ttl = ttl; + rdataset->trust = 0; + rdataset->private1 = NULL; + rdataset->private2 = NULL; + rdataset->private3 = slab + reservelen; + + /* + * Reset iterator state. + */ + rdataset->privateuint4 = 0; + rdataset->private5 = NULL; +} + +unsigned int +dns_rdataslab_size(unsigned char *slab, unsigned int reservelen) { + unsigned int count, length; + unsigned char *current; + + REQUIRE(slab != NULL); + + 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)); +} + +/* + * Make the dns_rdata_t 'rdata' refer to the slab item + * beginning at '*current', which is part of a slab of type + * 'type' and class 'rdclass', and advance '*current' to + * point to the next item in the slab. + */ +static inline void +rdata_from_slab(unsigned char **current, + dns_rdataclass_t rdclass, dns_rdatatype_t type, + dns_rdata_t *rdata) +{ + unsigned char *tcurrent = *current; + isc_region_t region; + unsigned int length; + isc_boolean_t offline = ISC_FALSE; + + length = *tcurrent++ * 256; + length += *tcurrent++; + + if (type == dns_rdatatype_rrsig) { + if ((*tcurrent & DNS_RDATASLAB_OFFLINE) != 0) + offline = ISC_TRUE; + length--; + tcurrent++; + } + region.length = length; +#if DNS_RDATASET_FIXED + tcurrent += 2; +#endif + region.base = tcurrent; + tcurrent += region.length; + dns_rdata_fromregion(rdata, rdclass, type, ®ion); + if (offline) + rdata->flags |= DNS_RDATA_OFFLINE; + *current = tcurrent; +} + +/* + * Return true iff 'slab' (slab data of type 'type' and class 'rdclass') + * contains an rdata identical to 'rdata'. This does case insensitive + * comparisons per DNSSEC. + */ +static inline isc_boolean_t +rdata_in_slab(unsigned char *slab, unsigned int reservelen, + dns_rdataclass_t rdclass, dns_rdatatype_t type, + dns_rdata_t *rdata) +{ + unsigned int count, i; + unsigned char *current; + dns_rdata_t trdata = DNS_RDATA_INIT; + int n; + + current = slab + reservelen; + count = *current++ * 256; + count += *current++; + +#if DNS_RDATASET_FIXED + current += (4 * count); +#endif + + for (i = 0; i < count; i++) { + rdata_from_slab(¤t, rdclass, type, &trdata); + + n = dns_rdata_compare(&trdata, rdata); + if (n == 0) + return (ISC_TRUE); + if (n > 0) /* In DNSSEC order. */ + break; + dns_rdata_reset(&trdata); + } + return (ISC_FALSE); +} + +isc_result_t +dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab, + unsigned int reservelen, isc_mem_t *mctx, + dns_rdataclass_t rdclass, dns_rdatatype_t type, + unsigned int flags, unsigned char **tslabp) +{ + unsigned char *ocurrent, *ostart, *ncurrent, *tstart, *tcurrent, *data; + unsigned int ocount, ncount, count, olength, tlength, tcount, length; + dns_rdata_t ordata = DNS_RDATA_INIT; + dns_rdata_t nrdata = DNS_RDATA_INIT; + isc_boolean_t added_something = ISC_FALSE; + 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, + * or perhaps another merge routine for this purpose. + */ + + REQUIRE(tslabp != NULL && *tslabp == NULL); + REQUIRE(oslab != NULL && nslab != NULL); + + 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! + */ + + /* + * Figure out the length of the old slab's data. + */ + olength = 0; + 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 + } + + /* + * Start figuring out the target length and count. + */ + tlength = reservelen + 2 + olength; + tcount = ocount; + + /* + * Add in the length of rdata in the new slab that aren't in + * the old slab. + */ + do { + dns_rdata_init(&nrdata); + rdata_from_slab(&ncurrent, rdclass, type, &nrdata); + if (!rdata_in_slab(oslab, reservelen, rdclass, type, &nrdata)) + { + /* + * This rdata isn't in the old slab. + */ +#if DNS_RDATASET_FIXED + tlength += nrdata.length + 8; +#else + tlength += nrdata.length + 2; +#endif + if (type == dns_rdatatype_rrsig) + tlength++; + tcount++; + nncount++; + added_something = ISC_TRUE; + } + ncount--; + } while (ncount > 0); + ncount = nncount; + + if (((flags & DNS_RDATASLAB_EXACT) != 0) && + (tcount != ncount + ocount)) + return (DNS_R_NOTEXACT); + + if (!added_something && (flags & DNS_RDATASLAB_FORCE) == 0) + return (DNS_R_UNCHANGED); + + /* + * Ensure that singleton types are actually singletons. + */ + if (tcount > 1 && dns_rdatatype_issingleton(type)) { + /* + * We have a singleton type, but there's more than one + * RR in the rdataset. + */ + return (DNS_R_SINGLETON); + } + + if (tcount > 0xffff) + return (ISC_R_NOSPACE); + + /* + * Copy the reserved area from the new slab. + */ + tstart = isc_mem_get(mctx, tlength); + if (tstart == NULL) + return (ISC_R_NOMEMORY); + memcpy(tstart, nslab, reservelen); + tcurrent = tstart + reservelen; +#if DNS_RDATASET_FIXED + offsetbase = tcurrent; +#endif + + /* + * Write the new count. + */ + *tcurrent++ = (tcount & 0xff00) >> 8; + *tcurrent++ = (tcount & 0x00ff); + +#if DNS_RDATASET_FIXED + /* + * Skip offset table. + */ + tcurrent += (tcount * 4); + + offsettable = isc_mem_get(mctx, + (ocount + oncount) * sizeof(unsigned int)); + if (offsettable == NULL) { + isc_mem_put(mctx, tstart, tlength); + 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); +#endif + rdata_from_slab(&ncurrent, rdclass, type, &nrdata); + } while (rdata_in_slab(oslab, reservelen, rdclass, + type, &nrdata)); + } + + while (oadded < ocount || nadded < ncount) { + isc_boolean_t fromold; + if (oadded == ocount) + fromold = ISC_FALSE; + else if (nadded == ncount) + fromold = ISC_TRUE; + else + fromold = ISC_TF(compare_rdata(&ordata, &nrdata) < 0); + if (fromold) { +#if DNS_RDATASET_FIXED + offsettable[oorder] = tcurrent - offsetbase; +#endif + length = ordata.length; + data = ordata.data; + if (type == dns_rdatatype_rrsig) { + length++; + data--; + } + *tcurrent++ = (length & 0xff00) >> 8; + *tcurrent++ = (length & 0x00ff); +#if DNS_RDATASET_FIXED + tcurrent += 2; /* fill in later */ +#endif + memcpy(tcurrent, 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); +#endif + rdata_from_slab(&ocurrent, rdclass, type, + &ordata); + } + } else { +#if DNS_RDATASET_FIXED + offsettable[ocount + norder] = tcurrent - offsetbase; +#endif + length = nrdata.length; + data = nrdata.data; + if (type == dns_rdatatype_rrsig) { + length++; + data--; + } + *tcurrent++ = (length & 0xff00) >> 8; + *tcurrent++ = (length & 0x00ff); +#if DNS_RDATASET_FIXED + tcurrent += 2; /* fill in later */ +#endif + memcpy(tcurrent, 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); +#endif + rdata_from_slab(&ncurrent, rdclass, + type, &nrdata); + } while (rdata_in_slab(oslab, reservelen, + rdclass, type, + &nrdata)); + } + } + } + +#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); + + *tslabp = tstart; + + return (ISC_R_SUCCESS); +} + +isc_result_t +dns_rdataslab_subtract(unsigned char *mslab, unsigned char *sslab, + unsigned int reservelen, isc_mem_t *mctx, + dns_rdataclass_t rdclass, dns_rdatatype_t type, + unsigned int flags, unsigned char **tslabp) +{ + unsigned char *mcurrent, *sstart, *scurrent, *tstart, *tcurrent; + 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; + unsigned int order; +#endif + + REQUIRE(tslabp != NULL && *tslabp == NULL); + REQUIRE(mslab != NULL && sslab != NULL); + + mcurrent = mslab + reservelen; + mcount = *mcurrent++ * 256; + mcount += *mcurrent++; + scurrent = sslab + reservelen; + scount = *scurrent++ * 256; + scount += *scurrent++; + INSIST(mcount > 0 && scount > 0); + + /* + * Yes, this is inefficient! + */ + + /* + * Start figuring out the target length and count. + */ + tlength = reservelen + 2; + tcount = 0; + rcount = 0; + +#if DNS_RDATASET_FIXED + mcurrent += 4 * mcount; + scurrent += 4 * scount; +#endif + sstart = scurrent; + + /* + * Add in the length of rdata in the mslab that aren't in + * the sslab. + */ + for (i = 0; i < mcount; i++) { + unsigned char *mrdatabegin = mcurrent; + rdata_from_slab(&mcurrent, rdclass, type, &mrdata); + scurrent = sstart; + for (count = 0; count < scount; count++) { + dns_rdata_reset(&srdata); + rdata_from_slab(&scurrent, rdclass, type, &srdata); + if (dns_rdata_compare(&mrdata, &srdata) == 0) + break; + } + if (count == scount) { + /* + * This rdata isn't in the sslab, and thus isn't + * being subtracted. + */ + tlength += mcurrent - mrdatabegin; + tcount++; + } else + rcount++; + 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. + */ + if (((flags & DNS_RDATASLAB_EXACT) != 0) && (rcount != scount)) + return (DNS_R_NOTEXACT); + + /* + * Don't continue if the new rdataslab would be empty. + */ + if (tcount == 0) + return (DNS_R_NXRRSET); + + /* + * If nothing is going to change, we can stop. + */ + if (rcount == 0) + return (DNS_R_UNCHANGED); + + /* + * Copy the reserved area from the mslab. + */ + tstart = isc_mem_get(mctx, tlength); + if (tstart == NULL) + 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)); + if (offsettable == NULL) { + isc_mem_put(mctx, tstart, tlength); + return (ISC_R_NOMEMORY); + } + memset(offsettable, 0, mcount * sizeof(unsigned int)); +#endif + + /* + * Write the new count. + */ + *tcurrent++ = (tcount & 0xff00) >> 8; + *tcurrent++ = (tcount & 0x00ff); + +#if DNS_RDATASET_FIXED + tcurrent += (4 * tcount); +#endif + + /* + * Copy the parts of mslab not in 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++) { + dns_rdata_reset(&srdata); + rdata_from_slab(&scurrent, rdclass, type, &srdata); + if (dns_rdata_compare(&mrdata, &srdata) == 0) + break; + } + if (count == scount) { + /* + * This rdata isn't in the sslab, and thus should be + * 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); + + *tslabp = tstart; + + return (ISC_R_SUCCESS); +} + +isc_boolean_t +dns_rdataslab_equal(unsigned char *slab1, unsigned char *slab2, + unsigned int reservelen) +{ + unsigned char *current1, *current2; + unsigned int count1, count2; + unsigned int length1, length2; + + current1 = slab1 + reservelen; + count1 = *current1++ * 256; + count1 += *current1++; + + current2 = slab2 + reservelen; + count2 = *current2++ * 256; + count2 += *current2++; + + if (count1 != count2) + return (ISC_FALSE); + +#if DNS_RDATASET_FIXED + current1 += (4 * count1); + current2 += (4 * count2); +#endif + + while (count1 > 0) { + length1 = *current1++ * 256; + length1 += *current1++; + + length2 = *current2++ * 256; + length2 += *current2++; + +#if DNS_RDATASET_FIXED + current1 += 2; + current2 += 2; +#endif + + if (length1 != length2 || + memcmp(current1, current2, length1) != 0) + return (ISC_FALSE); + + current1 += length1; + current2 += length1; + + count1--; + } + return (ISC_TRUE); +} + +isc_boolean_t +dns_rdataslab_equalx(unsigned char *slab1, unsigned char *slab2, + unsigned int reservelen, dns_rdataclass_t rdclass, + dns_rdatatype_t type) +{ + unsigned char *current1, *current2; + unsigned int count1, count2; + dns_rdata_t rdata1 = DNS_RDATA_INIT; + dns_rdata_t rdata2 = DNS_RDATA_INIT; + + current1 = slab1 + reservelen; + count1 = *current1++ * 256; + count1 += *current1++; + + current2 = slab2 + reservelen; + count2 = *current2++ * 256; + count2 += *current2++; + + if (count1 != count2) + return (ISC_FALSE); + +#if DNS_RDATASET_FIXED + current1 += (4 * count1); + current2 += (4 * count2); +#endif + + while (count1-- > 0) { + rdata_from_slab(¤t1, rdclass, type, &rdata1); + rdata_from_slab(¤t2, rdclass, type, &rdata2); + if (dns_rdata_compare(&rdata1, &rdata2) != 0) + return (ISC_FALSE); + dns_rdata_reset(&rdata1); + dns_rdata_reset(&rdata2); + } + return (ISC_TRUE); +} |