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Code Issues Releases Wiki Activity

clarify dns_rdataslab_fromrdataset()

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there are now two functions for creating an rdataslab from an
rdataset: dns_rdataslab_fromrdataset() creates a full slab (including
space for a slab header), and dns_rdataslab_raw_fromrdataset() creates
a raw slab.
This commit is contained in:
Evan Hunt
2025-02-07 20:07:53 -08:00
parent f1ab7f199b
commit b4bde9bef4
4 changed files with 44 additions and 24 deletions
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32
lib/dns/rdataslab.c
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@@ -47,7 +47,7 @@
* The rdataslab structure allows iteration to occur in both load order
* and DNSSEC order. The structure is as follows:
*
* header (reservelen bytes)
* header (dns_slabheader_t)
* record count (2 bytes)
* offset table (4 x record count bytes in load order)
* data records
@@ -56,6 +56,8 @@
* meta data (1 byte for RRSIG's)
* data (data length bytes)
*
* A "raw" rdataslab is the same but without the header.
*
* DNSSEC order traversal is performed by walking the data records.
*
* The order is stored with record to allow for efficient reconstruction
@@ -118,10 +120,9 @@ compare_rdata(const void *p1, const void *p2) {
return dns_rdata_compare(p1, p2);
}
isc_result_t
dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
isc_region_t *region, unsigned int reservelen,
uint32_t maxrrperset) {
static isc_result_t
makeslab(dns_rdataset_t *rdataset, isc_mem_t *mctx, isc_region_t *region,
uint32_t maxrrperset, bool raw) {
/*
* Use &removed as a sentinel pointer for duplicate
* rdata as rdata.data == NULL is valid.
@@ -129,6 +130,7 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
static unsigned char removed;
dns_rdata_t *rdata = NULL;
unsigned char *rawbuf = NULL;
unsigned int headerlen = raw ? 0 : sizeof(dns_slabheader_t);
unsigned int buflen;
isc_result_t result;
unsigned int nitems;
@@ -136,7 +138,7 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
unsigned int length;
unsigned int i;
buflen = reservelen + 2;
buflen = headerlen + 2;
nitems = dns_rdataset_count(rdataset);
@@ -151,7 +153,7 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
rawbuf = isc_mem_get(mctx, buflen);
region->base = rawbuf;
region->length = buflen;
rawbuf += reservelen;
rawbuf += headerlen;
*rawbuf++ = 0;
*rawbuf = 0;
return ISC_R_SUCCESS;
@@ -231,6 +233,7 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
* Don't forget the last item!
*/
buflen += (2 + rdata[i - 1].length);
/*
* Provide space to store the per RR meta data.
*/
@@ -259,7 +262,7 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
region->base = rawbuf;
region->length = buflen;
rawbuf += reservelen;
rawbuf += headerlen;
put_uint16(rawbuf, nitems);
@@ -272,6 +275,7 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
length++;
}
INSIST(length <= 0xffff);
put_uint16(rawbuf, length);
/*
@@ -295,6 +299,18 @@ free_rdatas:
return result;
}
isc_result_t
dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
isc_region_t *region, uint32_t maxrrperset) {
return makeslab(rdataset, mctx, region, maxrrperset, false);
}
isc_result_t
dns_rdataslab_raw_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
isc_region_t *region, uint32_t maxrrperset) {
return makeslab(rdataset, mctx, region, maxrrperset, true);
}
unsigned int
dns_rdataslab_sizeraw(unsigned char *slab) {
REQUIRE(slab != NULL);