Commit 575737b9 authored by Brian Wellington's avatar Brian Wellington
Browse files

Rewrite the name compression code to use a hashtable instead of an RBT and

avoid allocating memory in most cases.  This increases performance by
about 225% on the rc query test (~305 q/s to 990 q/s).
parent 4efa0480
......@@ -15,7 +15,7 @@
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: compress.c,v 1.36 2000/11/14 23:29:49 bwelling Exp $ */
/* $Id: compress.c,v 1.37 2000/12/29 00:59:38 bwelling Exp $ */
#define DNS_NAME_USEINLINE 1
......@@ -36,17 +36,12 @@
#define DCTX_MAGIC 0x44435458U /* DCTX */
#define VALID_DCTX(x) ISC_MAGIC_VALID(x, DCTX_MAGIC)
static void
free_offset(void *offset, void *mctx);
static isc_boolean_t
compress_find(dns_rbt_t *root, dns_name_t *name, dns_name_t *prefix,
dns_name_t *suffix, isc_uint16_t *offset,
isc_buffer_t *workspace);
compress_find(dns_compress_t *cctx, dns_name_t *name, dns_name_t *prefix,
dns_name_t *suffix, isc_uint16_t *offset);
static void
compress_add(dns_rbt_t *root, dns_name_t *prefix, dns_name_t *suffix,
isc_uint16_t offset, isc_boolean_t global16, isc_mem_t *mctx);
compress_add(dns_compress_t *cctx, dns_name_t *name, isc_uint16_t offset);
/***
*** Compression
......@@ -54,35 +49,44 @@ compress_add(dns_rbt_t *root, dns_name_t *prefix, dns_name_t *suffix,
isc_result_t
dns_compress_init(dns_compress_t *cctx, int edns, isc_mem_t *mctx) {
isc_result_t result;
unsigned int i;
REQUIRE(cctx != NULL);
REQUIRE(mctx != NULL);
cctx->allowed = 0;
cctx->rdata = 0;
cctx->global16 = ISC_FALSE;
cctx->edns = edns;
cctx->global = NULL;
result = dns_rbt_create(mctx, free_offset, mctx, &cctx->global);
if (result != ISC_R_SUCCESS)
return (result);
for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++)
cctx->table[i] = NULL;
cctx->mctx = mctx;
cctx->count = 0;
cctx->magic = CCTX_MAGIC;
return (ISC_R_SUCCESS);
}
void
dns_compress_invalidate(dns_compress_t *cctx) {
dns_compressnode_t *node;
unsigned int i;
REQUIRE(VALID_CCTX(cctx));
cctx->magic = 0;
if (cctx->global != NULL)
dns_rbt_destroy(&cctx->global);
if (cctx->table != NULL) {
for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
while (cctx->table[i] != NULL) {
node = cctx->table[i];
cctx->table[i] = cctx->table[i]->next;
if (node->count < DNS_COMPRESS_INITIALNODES)
continue;
isc_mem_put(cctx->mctx, node,
sizeof(dns_compressnode_t));
}
}
}
cctx->allowed = 0;
cctx->rdata = 0;
cctx->global16 = ISC_FALSE;
cctx->edns = -1;
}
......@@ -108,86 +112,41 @@ dns_compress_getedns(dns_compress_t *cctx) {
isc_boolean_t
dns_compress_findglobal(dns_compress_t *cctx, dns_name_t *name,
dns_name_t *prefix, dns_name_t *suffix,
isc_uint16_t *offset, isc_buffer_t *workspace)
isc_uint16_t *offset)
{
REQUIRE(VALID_CCTX(cctx));
REQUIRE(dns_name_isabsolute(name) == ISC_TRUE);
REQUIRE(offset != NULL);
return (compress_find(cctx->global, name, prefix, suffix, offset,
workspace));
return (compress_find(cctx, name, prefix, suffix, offset));
}
void
dns_compress_add(dns_compress_t *cctx, dns_name_t *prefix,
dns_name_t *suffix, isc_uint16_t offset)
{
dns_compress_add(dns_compress_t *cctx, dns_name_t *name, isc_uint16_t offset) {
REQUIRE(VALID_CCTX(cctx));
REQUIRE(dns_name_isabsolute(name));
compress_add(cctx->global, prefix, suffix, offset,
cctx->global16, cctx->mctx);
compress_add(cctx, name, offset);
}
void
dns_compress_rollback(dns_compress_t *cctx, isc_uint16_t offset) {
dns_rbtnode_t *node;
dns_fixedname_t foundfixed;
dns_fixedname_t fullfixed;
dns_fixedname_t originfixed;
dns_name_t *foundname;
dns_name_t *fullname;
dns_name_t *origin;
dns_rbtnodechain_t chain;
isc_result_t result;
unsigned int i;
dns_compressnode_t *node;
REQUIRE(VALID_CCTX(cctx));
/*
* Initalise things.
*/
dns_fixedname_init(&foundfixed);
foundname = dns_fixedname_name(&foundfixed);
dns_fixedname_init(&fullfixed);
fullname = dns_fixedname_name(&fullfixed);
dns_fixedname_init(&originfixed);
origin = dns_fixedname_name(&originfixed);
dns_rbtnodechain_init(&chain, cctx->mctx);
again:
result = dns_rbtnodechain_first(&chain, cctx->global, foundname,
origin);
while (result == DNS_R_NEWORIGIN || result == ISC_R_SUCCESS) {
result = dns_rbtnodechain_current(&chain, foundname,
origin, &node);
if (result != ISC_R_SUCCESS)
break;
if (node->data != NULL &&
(*(isc_uint16_t*)node->data >= offset)) {
result = dns_name_concatenate(foundname,
dns_name_isabsolute(foundname) ?
NULL : origin,
fullname, NULL);
if (result != ISC_R_SUCCESS)
break;
result = dns_rbt_deletename(cctx->global, fullname,
ISC_FALSE);
if (result != ISC_R_SUCCESS)
break;
/*
* If the delete is successful the chain is broken.
*/
dns_rbtnodechain_reset(&chain);
goto again;
for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
node = cctx->table[i];
while (node != NULL && node->offset >= offset) {
cctx->table[i] = node->next;
if (node->count >= DNS_COMPRESS_INITIALNODES)
isc_mem_put(cctx->mctx, node,
sizeof(dns_compressnode_t));
cctx->count--;
node = cctx->table[i];
}
result = dns_rbtnodechain_next(&chain, foundname, origin);
}
dns_rbtnodechain_invalidate(&chain);
}
/***
......@@ -262,177 +221,102 @@ dns_decompress_type(dns_decompress_t *dctx) {
*** Private
***/
static void
free_offset(void *offset, void *mctx) {
REQUIRE(offset != NULL);
REQUIRE(mctx != NULL);
isc_mem_put(mctx, offset, sizeof(isc_uint16_t));
}
/*
* Add the labels in prefix to RBT.
* Add the labels in prefix to the compression table.
*/
static void
compress_add(dns_rbt_t *root, dns_name_t *prefix, dns_name_t *suffix,
isc_uint16_t offset, isc_boolean_t global16, isc_mem_t *mctx)
{
dns_name_t name;
dns_name_t full;
compress_add(dns_compress_t *cctx, dns_name_t *name, isc_uint16_t offset) {
dns_name_t tname, nname;
dns_label_t label;
unsigned int count;
unsigned int start;
unsigned int n;
isc_uint16_t *data;
isc_result_t result;
unsigned char buffer[255];
isc_buffer_t target;
dns_offsets_t offsets;
count = dns_name_countlabels(prefix);
if (dns_name_isabsolute(prefix))
count--;
unsigned int hash;
dns_compressnode_t *node;
dns_name_init(&tname, NULL);
dns_name_init(&nname, NULL);
n = dns_name_countlabels(name);
start = 0;
dns_name_init(&full, offsets);
dns_name_init(&name, NULL);
isc_buffer_init(&target, buffer, sizeof(buffer));
result = dns_name_concatenate(prefix, suffix, &full, &target);
if (result != ISC_R_SUCCESS)
return;
n = dns_name_countlabels(&full);
while (count > 0) {
if (offset >= 16384 && !global16)
while (n > 1) {
if (offset >= 0x4000)
break;
dns_name_getlabelsequence(&full, start, n, &name);
data = isc_mem_get(mctx, sizeof *data);
if (data == NULL)
return;
*data = offset;
result = dns_rbt_addname(root, &name, data);
if (result != ISC_R_SUCCESS) {
isc_mem_put(mctx, data, sizeof *data);
return;
dns_name_getlabelsequence(name, start, n, &tname);
hash = dns_name_hash(&tname, ISC_FALSE) % DNS_COMPRESS_TABLESIZE;
/*
* Look for the name in the hash bucket. If it's there,
* we're done.
*/
for (node = cctx->table[hash]; node != NULL; node = node->next)
{
dns_name_fromregion(&nname, &node->r);
if (dns_name_equal(&nname, &tname))
return;
}
/*
* It's not there. Create a new node and add it.
*/
if (cctx->count < DNS_COMPRESS_INITIALNODES)
node = &cctx->initialnodes[cctx->count];
else {
node = isc_mem_get(cctx->mctx,
sizeof(dns_compressnode_t));
if (node == NULL)
return;
}
dns_name_getlabel(&name, 0, &label);
node->count = cctx->count++;
node->offset = offset;
dns_name_toregion(&tname, &node->r);
node->next = cctx->table[hash];
cctx->table[hash] = node;
dns_name_getlabel(&tname, 0, &label);
offset += label.length;
start++;
n--;
count--;
}
}
/*
* Find the longest match of name in root.
* If match is found return ISC_TRUE. prefix, suffix and offset
* are updated.
* If no match is found return ISC_FALSE.
* Find the longest match of name in the table.
* If match is found return ISC_TRUE. prefix, suffix and offset are updated.
* If no match is found return ISC_FALSE.
*/
static isc_boolean_t
compress_find(dns_rbt_t *root, dns_name_t *name, dns_name_t *prefix,
dns_name_t *suffix, isc_uint16_t *offset,
isc_buffer_t *workspace)
compress_find(dns_compress_t *cctx,
dns_name_t *name, dns_name_t *prefix,
dns_name_t *suffix, isc_uint16_t *offset)
{
dns_fixedname_t found;
dns_name_t *foundname;
dns_name_t tmpprefix;
dns_name_t tmpsuffix;
isc_result_t result;
isc_uint16_t *data = NULL;
dns_label_t foundlabel;
dns_label_t namelabel;
unsigned int foundlabels;
unsigned int namelabels;
unsigned int foundbits;
unsigned int namebits;
unsigned int bits;
unsigned int prefixlen;
unsigned int j;
unsigned char buf[2 + 256/8]; /* size of biggest bit label */
dns_bitlabel_t bit;
isc_region_t region;
dns_fixedname_init(&found);
foundname = dns_fixedname_name(&found);
/*
* Getting rid of the offsets table for foundname improves
* perfomance, since the offsets table is not needed and maintaining
* it has costs.
*/
foundname->offsets = NULL;
result = dns_rbt_findname(root, name, 0, foundname, (void *)&data);
if (result != ISC_R_SUCCESS && result != DNS_R_PARTIALMATCH)
return (ISC_FALSE);
if (data == NULL) /* root label */
return (ISC_FALSE);
/*
* Do we have to do bit string processing?
*/
dns_name_getlabel(foundname, 0, &foundlabel);
foundlabels = dns_name_countlabels(foundname);
INSIST(foundlabels > 1); /* root labels are not added to tree */
namelabels = dns_name_countlabels(name);
if (dns_label_type(&foundlabel) == dns_labeltype_bitstring) {
dns_name_getlabel(name, namelabels - foundlabels, &namelabel);
INSIST(dns_label_type(&namelabel) == dns_labeltype_bitstring);
foundbits = dns_label_countbits(&foundlabel);
namebits = dns_label_countbits(&namelabel);
} else
namebits = foundbits = 0;
if (namebits == foundbits) {
INSIST(namelabels >= foundlabels);
prefixlen = namelabels - foundlabels;
if (prefixlen == 0) {
prefix->length = 0;
prefix->labels = 0;
} else
dns_name_getlabelsequence(name, 0, prefixlen, prefix);
result = dns_name_concatenate(NULL, foundname, suffix,
workspace);
if (result != ISC_R_SUCCESS)
return (ISC_FALSE);
*offset = *data;
return (ISC_TRUE);
}
/*
* At this stage we have a bit string label to split in two.
* There is potentially a prefix before this label and definitly
* a suffix after it (if only the root).
*/
INSIST(result == DNS_R_PARTIALMATCH);
result = dns_name_concatenate(NULL, foundname, suffix, workspace);
if (result != ISC_R_SUCCESS)
return (ISC_FALSE);
prefixlen = namelabels - foundlabels;
dns_name_init(&tmpprefix, NULL);
dns_name_init(&tmpsuffix, NULL);
if (prefixlen != 0) {
dns_name_getlabelsequence(name, 0, prefixlen, &tmpprefix);
dns_name_t tname, nname;
dns_compressnode_t *node;
unsigned int labels, hash, n;
labels = dns_name_countlabels(name);
INSIST(labels > 0);
dns_name_init(&tname, NULL);
dns_name_init(&nname, NULL);
for (n = 0; n < labels - 1; n++) {
dns_name_getlabelsequence(name, n, labels - n, &tname);
hash = dns_name_hash(&tname, ISC_FALSE) % DNS_COMPRESS_TABLESIZE;
for (node = cctx->table[hash]; node != NULL; node = node->next)
{
dns_name_fromregion(&nname, &node->r);
if (dns_name_equal(&nname, &tname))
break;
}
if (node != NULL)
break;
}
INSIST(namebits > foundbits);
bits = namebits - foundbits;
j = 0;
memset(buf, 0, sizeof buf);
INSIST((bits / 8 + 1) < sizeof buf);
/*
* Copy least significant bits.
* If node == NULL, we found no match at all.
*/
while (j < bits) {
bit = dns_label_getbit(&namelabel, foundbits + j);
if (bit)
buf[2 + j / 8] |= (1 << (7 - (j % 8)));
j++;
}
buf[0] = DNS_LABELTYPE_BITSTRING;
buf[1] = j;
region.base = buf;
region.length = 2 + (j + 7) / 8;
dns_name_fromregion(&tmpsuffix, &region);
result = dns_name_concatenate(&tmpprefix, &tmpsuffix, prefix,
workspace);
if (result != ISC_R_SUCCESS)
if (node == NULL)
return (ISC_FALSE);
*offset = *data;
dns_name_clone(&tname, suffix);
dns_name_getlabelsequence(name, 0, n, prefix);
*offset = node->offset;
return (ISC_TRUE);
}
<
......@@ -15,12 +15,13 @@
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: compress.h,v 1.20 2000/12/28 00:42:56 bwelling Exp $ */
/* $Id: compress.h,v 1.21 2000/12/29 00:59:41 bwelling Exp $ */
#ifndef DNS_COMPRESS_H
#define DNS_COMPRESS_H 1
#include <isc/lang.h>
#include <isc/region.h>
#include <dns/types.h>
......@@ -28,28 +29,35 @@ ISC_LANG_BEGINDECLS
#define DNS_COMPRESS_NONE 0x00 /* no compression */
#define DNS_COMPRESS_GLOBAL14 0x01 /* "normal" compression. */
#define DNS_COMPRESS_GLOBAL 0x01 /* all global comp. */
/*
* Synonymous with DNS_COMPRESS_GLOBAL. A genuine difference existed when
* local compression was an IETF draft, but that draft has been retired without
* becoming a standard. Numerous bits of code referred to DNS_COMPRESS_ALL
* already, and rather than change them all, the DNS_COMPRESS_ALL definition
* was left in, but no longer refers to local compression.
*/
#define DNS_COMPRESS_ALL 0x03 /* all compression. */
#define DNS_COMPRESS_ALL 0x01 /* all compression. */
/*
* Direct manipulation of the structures is strongly discouraged.
*/
#define DNS_COMPRESS_TABLESIZE 64
#define DNS_COMPRESS_INITIALNODES 16
typedef struct dns_compressnode dns_compressnode_t;
struct dns_compressnode {
isc_region_t r;
isc_uint16_t offset;
isc_uint16_t count;
dns_compressnode_t *next;
};
struct dns_compress {
unsigned int magic; /* Magic number. */
unsigned int allowed; /* Allowed methods. */
unsigned int rdata; /* Start of local rdata. */
isc_boolean_t global16; /* 16 bit offsets allowed. */
int edns; /* Edns version or -1. */
dns_rbt_t *global; /* Global RBT. */
isc_mem_t *mctx; /* Memeory context. */
unsigned int magic; /* Magic number. */
unsigned int allowed; /* Allowed methods. */
unsigned int rdata; /* Start of local rdata. */
int edns; /* Edns version or -1. */
/* Global compression table. */
dns_compressnode_t *table[DNS_COMPRESS_TABLESIZE];
/* Preallocated nodes for the table. */
dns_compressnode_t initialnodes[DNS_COMPRESS_INITIALNODES];
isc_uint16_t count; /* Number of nodes. */
isc_mem_t *mctx; /* Memory context. */
};
typedef enum {
......@@ -73,9 +81,9 @@ dns_compress_init(dns_compress_t *cctx, int edns, isc_mem_t *mctx);
*
* Requires:
* 'cctx' is a valid dns_compress_t structure.
* 'mctx' is a initalised memory context.
* 'mctx' is an initialized memory context.
* Ensures:
* cctx->global is initalised.
* cctx->global is initialized.
*
* Returns:
* ISC_R_SUCCESS
......@@ -87,10 +95,9 @@ dns_compress_invalidate(dns_compress_t *cctx);
/*
* Invalidate the compression structure pointed to by cctx.
* Destroys 'cctx->glocal' and 'cctx->local' RBT.
*
* Requires:
* 'cctx' to be initalised.
* 'cctx' to be initialized.
*/
void
......@@ -100,7 +107,7 @@ dns_compress_setmethods(dns_compress_t *cctx, unsigned int allowed);
* Sets allowed compression methods.
*
* Requires:
* 'cctx' to be initalised.
* 'cctx' to be initialized.
*/
unsigned int
......@@ -110,7 +117,7 @@ dns_compress_getmethods(dns_compress_t *cctx);
* Gets allowed compression methods.
*
* Requires:
* 'cctx' to be initalised.
* 'cctx' to be initialized.
*
* Returns:
* allowed compression bitmap.
......@@ -123,7 +130,7 @@ dns_compress_getedns(dns_compress_t *cctx);
* Gets edns value.
*
* Requires:
* 'cctx' to be initalised.
* 'cctx' to be initialized.
*
* Returns:
* -1 .. 255
......@@ -132,19 +139,16 @@ dns_compress_getedns(dns_compress_t *cctx);
isc_boolean_t
dns_compress_findglobal(dns_compress_t *cctx, dns_name_t *name,
dns_name_t *prefix, dns_name_t *suffix,
isc_uint16_t *offset, isc_buffer_t *workspace);
isc_uint16_t *offset);
/*
* Finds longest possible match of 'name' in the global compression
* RBT. Workspace needs to be large enough to hold 'name' when split
* in two (length->name + 3).
* Finds longest possible match of 'name' in the global compression table.
*
* Requires:
* 'cctx' to be initalised.
* 'cctx' to be initialized.
* 'name' to be a absolute name.
* 'prefix' to be initalised.
* 'suffix' to be initalised.
* 'prefix' to be initialized.
* 'suffix' to be initialized.
* 'offset' to point it a isc_uint16_t.
* 'workspace' to be initalised.
*
* Ensures:
* 'prefix', 'suffix' and 'offset' are valid if ISC_TRUE is
......@@ -155,27 +159,24 @@ dns_compress_findglobal(dns_compress_t *cctx, dns_name_t *name,
*/
void
dns_compress_add(dns_compress_t *cctx, dns_name_t *prefix,
dns_name_t *suffix, isc_uint16_t offset);
dns_compress_add(dns_compress_t *cctx, dns_name_t *name, isc_uint16_t offset);
/*
* Add compression pointers for labels in prefix to RBT's.
* If 'prefix' is absolute 'suffix' must be NULL otherwise
* suffix must be absolute.
* Add compression pointers for name to the compression table,
* not replacing existing pointers.
*
* Requires:
* 'cctx' initalised
* 'prefix' to be initalised
* 'suffix' to be initalised or NULL
* 'cctx' initialized
* 'name' must be initialized and absolute
*/
void
dns_compress_rollback(dns_compress_t *cctx, isc_uint16_t offset);
/*
* Remove any compression pointers from global RBT >= offset.
* Remove any compression pointers from global table >= offset.
*
* Requires:
* 'cctx' is initalised.
* 'cctx' is initialized.
*/
void
......@@ -197,7 +198,7 @@ dns_decompress_invalidate(dns_decompress_t *dctx);
* Invalidates 'dctx'.
*
* Requires:
* 'dctx' to be initalised
* 'dctx' to be initialized
*/
void
......@@ -207,7 +208,7 @@ dns_decompress_setmethods(dns_decompress_t *dctx, unsigned int allowed);
* Sets 'dctx->allowed' to 'allowed'.
*
* Requires:
* 'dctx' to be initalised
* 'dctx' to be initialized
*/
unsigned int