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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 07:24:22 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 07:24:22 +0000 |
commit | 45d6379135504814ab723b57f0eb8be23393a51d (patch) | |
tree | d4f2ec4acca824a8446387a758b0ce4238a4dffa /lib/dns/rdataslab.c | |
parent | Initial commit. (diff) | |
download | bind9-45d6379135504814ab723b57f0eb8be23393a51d.tar.xz bind9-45d6379135504814ab723b57f0eb8be23393a51d.zip |
Adding upstream version 1:9.16.44.upstream/1%9.16.44upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/dns/rdataslab.c')
-rw-r--r-- | lib/dns/rdataslab.c | 1005 |
1 files changed, 1005 insertions, 0 deletions
diff --git a/lib/dns/rdataslab.c b/lib/dns/rdataslab.c new file mode 100644 index 0000000..2783c1c --- /dev/null +++ b/lib/dns/rdataslab.c @@ -0,0 +1,1005 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, you can obtain one at https://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +/*! \file */ + +#include <stdbool.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/rdata.h> +#include <dns/rdataset.h> +#include <dns/rdataslab.h> +#include <dns/result.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) + * meta data (1 byte for RRSIG's) + * 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 reconstruction + * of the offset table following a merge or subtraction. + * + * 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 /* if DNS_RDATASET_FIXED */ + +isc_result_t +dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx, + isc_region_t *region, unsigned int reservelen) { + /* + * Use &removed as a sentinel pointer for duplicate + * rdata as rdata.data == NULL is valid. + */ + static unsigned char removed; + struct xrdata *x; + unsigned char *rawbuf; +#if DNS_RDATASET_FIXED + unsigned char *offsetbase; +#endif /* if DNS_RDATASET_FIXED */ + unsigned int buflen; + isc_result_t result; + unsigned int nitems; + unsigned int nalloc; + unsigned int i; +#if DNS_RDATASET_FIXED + unsigned int *offsettable; +#endif /* if DNS_RDATASET_FIXED */ + unsigned int length; + + buflen = reservelen + 2; + + nitems = dns_rdataset_count(rdataset); + + /* + * If there are no rdata then we can just need to allocate a header + * with zero a record count. + */ + if (nitems == 0) { + if (rdataset->type != 0) { + return (ISC_R_FAILURE); + } + rawbuf = isc_mem_get(mctx, buflen); + region->base = rawbuf; + region->length = buflen; + rawbuf += reservelen; + *rawbuf++ = 0; + *rawbuf = 0; + return (ISC_R_SUCCESS); + } + + if (nitems > 0xffff) { + return (ISC_R_NOSPACE); + } + + /* + * Remember the original number of items. + */ + nalloc = nitems; + x = isc_mem_get(mctx, nalloc * sizeof(struct xrdata)); + + /* + * Save all of the rdata members into an array. + */ + result = dns_rdataset_first(rdataset); + if (result != ISC_R_SUCCESS && result != ISC_R_NOMORE) { + 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); + INSIST(x[i].rdata.data != &removed); +#if DNS_RDATASET_FIXED + x[i].order = i; +#endif /* if DNS_RDATASET_FIXED */ + result = dns_rdataset_next(rdataset); + } + if (i != nalloc || result != ISC_R_NOMORE) { + /* + * Somehow we iterated over fewer rdatas than + * dns_rdataset_count() said there were or there + * were more items than dns_rdataset_count said + * there were. + */ + result = ISC_R_FAILURE; + goto free_rdatas; + } + + /* + * Put into DNSSEC order. + */ + if (nalloc > 1U) { + 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 = &removed; +#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 /* if DNS_RDATASET_FIXED */ + nitems--; + } else { +#if DNS_RDATASET_FIXED + buflen += (8 + x[i - 1].rdata.length); +#else /* if DNS_RDATASET_FIXED */ + buflen += (2 + x[i - 1].rdata.length); +#endif /* if DNS_RDATASET_FIXED */ + /* + * 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 /* if DNS_RDATASET_FIXED */ + buflen += (2 + x[i - 1].rdata.length); +#endif /* if DNS_RDATASET_FIXED */ + /* + * 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 DNS_RDATASET_FIXED + /* Allocate temporary offset table. */ + offsettable = isc_mem_get(mctx, nalloc * sizeof(unsigned int)); + memset(offsettable, 0, nalloc * sizeof(unsigned int)); +#endif /* if DNS_RDATASET_FIXED */ + + region->base = rawbuf; + region->length = buflen; + + memset(rawbuf, 0, buflen); + rawbuf += reservelen; + +#if DNS_RDATASET_FIXED + offsetbase = rawbuf; +#endif /* if DNS_RDATASET_FIXED */ + + *rawbuf++ = (nitems & 0xff00) >> 8; + *rawbuf++ = (nitems & 0x00ff); + +#if DNS_RDATASET_FIXED + /* Skip load order table. Filled in later. */ + rawbuf += nitems * 4; +#endif /* if DNS_RDATASET_FIXED */ + + for (i = 0; i < nalloc; i++) { + if (x[i].rdata.data == &removed) { + continue; + } +#if DNS_RDATASET_FIXED + offsettable[x[i].order] = rawbuf - offsetbase; +#endif /* if DNS_RDATASET_FIXED */ + length = x[i].rdata.length; + if (rdataset->type == dns_rdatatype_rrsig) { + length++; + } + INSIST(length <= 0xffff); + *rawbuf++ = (length & 0xff00) >> 8; + *rawbuf++ = (length & 0x00ff); +#if DNS_RDATASET_FIXED + rawbuf += 2; /* filled in later */ +#endif /* if DNS_RDATASET_FIXED */ + /* + * Store the per RR meta data. + */ + if (rdataset->type == dns_rdatatype_rrsig) { + *rawbuf++ = (x[i].rdata.flags & DNS_RDATA_OFFLINE) + ? DNS_RDATASLAB_OFFLINE + : 0; + } + memmove(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 /* if DNS_RDATASET_FIXED */ + + result = ISC_R_SUCCESS; + +free_rdatas: + isc_mem_put(mctx, x, nalloc * sizeof(struct xrdata)); + return (result); +} + +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 /* if DNS_RDATASET_FIXED */ + while (count > 0) { + count--; + length = *current++ * 256; + length += *current++; +#if DNS_RDATASET_FIXED + current += length + 2; +#else /* if DNS_RDATASET_FIXED */ + current += length; +#endif /* if DNS_RDATASET_FIXED */ + } + + return ((unsigned int)(current - slab)); +} + +unsigned int +dns_rdataslab_rdatasize(unsigned char *slab, unsigned int reservelen) { + unsigned int count, length, rdatalen = 0; + unsigned char *current; + + REQUIRE(slab != NULL); + + current = slab + reservelen; + count = *current++ * 256; + count += *current++; +#if DNS_RDATASET_FIXED + current += (4 * count); +#endif /* if DNS_RDATASET_FIXED */ + while (count > 0) { + count--; + length = *current++ * 256; + length += *current++; + rdatalen += length; +#if DNS_RDATASET_FIXED + current += length + 2; +#else /* if DNS_RDATASET_FIXED */ + current += length; +#endif /* if DNS_RDATASET_FIXED */ + } + + return (rdatalen); +} + +unsigned int +dns_rdataslab_count(unsigned char *slab, unsigned int reservelen) { + unsigned int count; + unsigned char *current; + + REQUIRE(slab != NULL); + + current = slab + reservelen; + count = *current++ * 256; + count += *current++; + return (count); +} + +/* + * 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 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; + bool offline = false; + + length = *tcurrent++ * 256; + length += *tcurrent++; + + if (type == dns_rdatatype_rrsig) { + if ((*tcurrent & DNS_RDATASLAB_OFFLINE) != 0) { + offline = true; + } + length--; + tcurrent++; + } + region.length = length; +#if DNS_RDATASET_FIXED + tcurrent += 2; +#endif /* if DNS_RDATASET_FIXED */ + 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 bool +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 /* if DNS_RDATASET_FIXED */ + + for (i = 0; i < count; i++) { + rdata_from_slab(¤t, rdclass, type, &trdata); + + n = dns_rdata_compare(&trdata, rdata); + if (n == 0) { + return (true); + } + if (n > 0) { /* In DNSSEC order. */ + break; + } + dns_rdata_reset(&trdata); + } + return (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; + bool added_something = 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 /* if DNS_RDATASET_FIXED */ + + /* + * 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 /* if DNS_RDATASET_FIXED */ + ostart = ocurrent; + ncurrent = nslab + reservelen; + ncount = *ncurrent++ * 256; + ncount += *ncurrent++; +#if DNS_RDATASET_FIXED + ncurrent += (4 * ncount); +#endif /* if DNS_RDATASET_FIXED */ + INSIST(ocount > 0 && ncount > 0); + +#if DNS_RDATASET_FIXED + oncount = ncount; +#endif /* if DNS_RDATASET_FIXED */ + + /* + * 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 /* if DNS_RDATASET_FIXED */ + olength += length + 2; + ocurrent += length; +#endif /* if DNS_RDATASET_FIXED */ + } + + /* + * 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 /* if DNS_RDATASET_FIXED */ + tlength += nrdata.length + 2; +#endif /* if DNS_RDATASET_FIXED */ + if (type == dns_rdatatype_rrsig) { + tlength++; + } + tcount++; + nncount++; + added_something = 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); + memmove(tstart, nslab, reservelen); + tcurrent = tstart + reservelen; +#if DNS_RDATASET_FIXED + offsetbase = tcurrent; +#endif /* if DNS_RDATASET_FIXED */ + + /* + * 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)); + memset(offsettable, 0, (ocount + oncount) * sizeof(unsigned int)); +#endif /* if DNS_RDATASET_FIXED */ + + /* + * Merge the two slabs. + */ + ocurrent = ostart; + INSIST(ocount != 0); +#if DNS_RDATASET_FIXED + oorder = ocurrent[2] * 256 + ocurrent[3]; + INSIST(oorder < ocount); +#endif /* if DNS_RDATASET_FIXED */ + rdata_from_slab(&ocurrent, rdclass, type, &ordata); + + ncurrent = nslab + reservelen + 2; +#if DNS_RDATASET_FIXED + ncurrent += (4 * oncount); +#endif /* if DNS_RDATASET_FIXED */ + + if (ncount > 0) { + do { + dns_rdata_reset(&nrdata); +#if DNS_RDATASET_FIXED + norder = ncurrent[2] * 256 + ncurrent[3]; + + INSIST(norder < oncount); +#endif /* if DNS_RDATASET_FIXED */ + rdata_from_slab(&ncurrent, rdclass, type, &nrdata); + } while (rdata_in_slab(oslab, reservelen, rdclass, type, + &nrdata)); + } + + while (oadded < ocount || nadded < ncount) { + bool fromold; + if (oadded == ocount) { + fromold = false; + } else if (nadded == ncount) { + fromold = true; + } else { + fromold = (dns_rdata_compare(&ordata, &nrdata) < 0); + } + if (fromold) { +#if DNS_RDATASET_FIXED + offsettable[oorder] = tcurrent - offsetbase; +#endif /* if DNS_RDATASET_FIXED */ + 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 /* if DNS_RDATASET_FIXED */ + memmove(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 /* if DNS_RDATASET_FIXED */ + rdata_from_slab(&ocurrent, rdclass, type, + &ordata); + } + } else { +#if DNS_RDATASET_FIXED + offsettable[ocount + norder] = tcurrent - offsetbase; +#endif /* if DNS_RDATASET_FIXED */ + 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 /* if DNS_RDATASET_FIXED */ + memmove(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 /* if DNS_RDATASET_FIXED */ + 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 /* if DNS_RDATASET_FIXED */ + + 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 /* if DNS_RDATASET_FIXED */ + + 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 /* if DNS_RDATASET_FIXED */ + 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 += (unsigned int)(mcurrent - mrdatabegin); + tcount++; + } else { + rcount++; + } + dns_rdata_reset(&mrdata); + } + +#if DNS_RDATASET_FIXED + tlength += (4 * tcount); +#endif /* if DNS_RDATASET_FIXED */ + + /* + * 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); + memmove(tstart, mslab, reservelen); + tcurrent = tstart + reservelen; +#if DNS_RDATASET_FIXED + offsetbase = tcurrent; + + offsettable = isc_mem_get(mctx, mcount * sizeof(unsigned int)); + memset(offsettable, 0, mcount * sizeof(unsigned int)); +#endif /* if DNS_RDATASET_FIXED */ + + /* + * Write the new count. + */ + *tcurrent++ = (tcount & 0xff00) >> 8; + *tcurrent++ = (tcount & 0x00ff); + +#if DNS_RDATASET_FIXED + tcurrent += (4 * tcount); +#endif /* if DNS_RDATASET_FIXED */ + + /* + * Copy the parts of mslab not in sslab. + */ + mcurrent = mslab + reservelen; + mcount = *mcurrent++ * 256; + mcount += *mcurrent++; +#if DNS_RDATASET_FIXED + mcurrent += (4 * mcount); +#endif /* if DNS_RDATASET_FIXED */ + for (i = 0; i < mcount; i++) { + unsigned char *mrdatabegin = mcurrent; +#if DNS_RDATASET_FIXED + order = mcurrent[2] * 256 + mcurrent[3]; + INSIST(order < mcount); +#endif /* if DNS_RDATASET_FIXED */ + 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; + length = (unsigned int)(mcurrent - mrdatabegin); +#if DNS_RDATASET_FIXED + offsettable[order] = tcurrent - offsetbase; +#endif /* if DNS_RDATASET_FIXED */ + memmove(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 /* if DNS_RDATASET_FIXED */ + + INSIST(tcurrent == tstart + tlength); + + *tslabp = tstart; + + return (ISC_R_SUCCESS); +} + +bool +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 (false); + } + +#if DNS_RDATASET_FIXED + current1 += (4 * count1); + current2 += (4 * count2); +#endif /* if DNS_RDATASET_FIXED */ + + while (count1 > 0) { + length1 = *current1++ * 256; + length1 += *current1++; + + length2 = *current2++ * 256; + length2 += *current2++; + +#if DNS_RDATASET_FIXED + current1 += 2; + current2 += 2; +#endif /* if DNS_RDATASET_FIXED */ + + if (length1 != length2 || + memcmp(current1, current2, length1) != 0) + { + return (false); + } + + current1 += length1; + current2 += length1; + + count1--; + } + return (true); +} + +bool +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 (false); + } + +#if DNS_RDATASET_FIXED + current1 += (4 * count1); + current2 += (4 * count2); +#endif /* if DNS_RDATASET_FIXED */ + + 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 (false); + } + dns_rdata_reset(&rdata1); + dns_rdata_reset(&rdata2); + } + return (true); +} |