void
dns_compress_setmethods(dns_compress_t *cctx, unsigned int allowed) {
REQUIRE(VALID_CCTX(cctx));
cctx->allowed &= ~DNS_COMPRESS_ALL;
cctx->allowed |= (allowed & DNS_COMPRESS_ALL);
}
void
dns_compress_rollback(dns_compress_t *cctx, isc_uint16_t offset) {
unsigned int i;
dns_compressnode_t *node;
REQUIRE(VALID_CCTX(cctx));
if (ISC_UNLIKELY((cctx->allowed & DNS_COMPRESS_ENABLED) == 0))
return;
for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
node = cctx->table[i];
/*
* This relies on nodes with greater offsets being
* closer to the beginning of the list, and the
* items with the greatest offsets being at the end
* of the initialnodes[] array.
*/
while (node != NULL && (node->offset & 0x7fff) >= offset) {
cctx->table[i] = node->next;
if ((node->offset & 0x8000) != 0)
isc_mem_put(cctx->mctx, node->r.base,
node->r.length);
if (node->count >= DNS_COMPRESS_INITIALNODES)
isc_mem_put(cctx->mctx, node, sizeof(*node));
cctx->count--;
node = cctx->table[i];
}
}
}
void
dns_compress_setsensitive(dns_compress_t *cctx, isc_boolean_t sensitive) {
REQUIRE(VALID_CCTX(cctx));
if (sensitive)
cctx->allowed |= DNS_COMPRESS_CASESENSITIVE;
else
cctx->allowed &= ~DNS_COMPRESS_CASESENSITIVE;
}
void
dns_compress_add(dns_compress_t *cctx, const dns_name_t *name,
const dns_name_t *prefix, isc_uint16_t offset)
{
dns_name_t tname;
unsigned int start;
unsigned int n;
unsigned int count;
unsigned int hash;
dns_compressnode_t *node;
unsigned int length;
unsigned int tlength;
isc_uint16_t toffset;
REQUIRE(VALID_CCTX(cctx));
REQUIRE(dns_name_isabsolute(name));
dns_name_init(&tname, NULL);
n = dns_name_countlabels(name);
count = dns_name_countlabels(prefix);
if (dns_name_isabsolute(prefix))
count--;
start = 0;
length = name_length(name);
while (count > 0) {
if (offset >= 0x4000)
break;
dns_name_getlabelsequence(name, start, n, &tname);
hash = dns_name_hash(&tname, ISC_FALSE) %
DNS_COMPRESS_TABLESIZE;
tlength = name_length(&tname);
toffset = (isc_uint16_t)(offset + (length - tlength));
/*
* 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;
}
node->count = cctx->count++;
node->offset = toffset;
dns_name_toregion(&tname, &node->r);
node->labels = (isc_uint8_t)dns_name_countlabels(&tname);
node->next = cctx->table[hash];
cctx->table[hash] = node;
start++;
n--;
count--;
}
}
/*
* 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.
*/
isc_boolean_t
dns_compress_findglobal(dns_compress_t *cctx, const dns_name_t *name,
dns_name_t *prefix, isc_uint16_t *offset)
{
dns_name_t tname, nname;
dns_compressnode_t *node = NULL;
unsigned int labels, hash, n;
REQUIRE(VALID_CCTX(cctx));
REQUIRE(dns_name_isabsolute(name) == ISC_TRUE);
REQUIRE(offset != NULL);
if (cctx->count == 0)
return (ISC_FALSE);
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)
{
NODENAME(node, &nname);
if ((cctx->allowed & DNS_COMPRESS_CASESENSITIVE) != 0) {
if (dns_name_caseequal(&nname, &tname))
break;
} else {
if (dns_name_equal(&nname, &tname))
break;
}
}
if (node != NULL)
break;
}
/*
* If node == NULL, we found no match at all.
*/
if (node == NULL)
return (ISC_FALSE);
if (n == 0)
dns_name_reset(prefix);
else
dns_name_getlabelsequence(name, 0, n, prefix);
*offset = node->offset;
return (ISC_TRUE);
}
void
dns_compress_invalidate(dns_compress_t *cctx) {
dns_compressnode_t *node;
unsigned int i;
REQUIRE(VALID_CCTX(cctx));
cctx->magic = 0;
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(*node));
}
}
cctx->allowed = 0;
cctx->edns = -1;
}
unsigned int
dns_compress_getmethods(dns_compress_t *cctx) {
REQUIRE(VALID_CCTX(cctx));
return (cctx->allowed & DNS_COMPRESS_ALL);
}
int
dns_compress_getedns(dns_compress_t *cctx) {
REQUIRE(VALID_CCTX(cctx));
return (cctx->edns);
}
isc_boolean_t
dns_compress_getsensitive(dns_compress_t *cctx) {
REQUIRE(VALID_CCTX(cctx));
return (ISC_TF((cctx->allowed & DNS_COMPRESS_CASESENSITIVE) != 0));
}
void
dns_compress_add(dns_compress_t *cctx, const dns_name_t *name,
const dns_name_t *prefix, isc_uint16_t offset)
{
dns_name_t tname, xname;
unsigned int start;
unsigned int n;
unsigned int count;
unsigned int i;
dns_compressnode_t *node;
unsigned int length;
unsigned int tlength;
isc_uint16_t toffset;
unsigned char *tmp;
isc_region_t r;
REQUIRE(VALID_CCTX(cctx));
REQUIRE(dns_name_isabsolute(name));
if (ISC_UNLIKELY((cctx->allowed & DNS_COMPRESS_ENABLED) == 0))
return;
if (offset >= 0x4000)
return;
dns_name_init(&tname, NULL);
dns_name_init(&xname, NULL);
n = dns_name_countlabels(name);
count = dns_name_countlabels(prefix);
if (dns_name_isabsolute(prefix))
count--;
if (count == 0)
return;
start = 0;
dns_name_toregion(name, &r);
length = r.length;
tmp = isc_mem_get(cctx->mctx, length);
if (tmp == NULL)
return;
/*
* Copy name data to 'tmp' and make 'r' use 'tmp'.
*/
memmove(tmp, r.base, r.length);
r.base = tmp;
dns_name_fromregion(&xname, &r);
if (count > 2U)
count = 2U;
while (count > 0) {
unsigned char ch;
dns_name_getlabelsequence(&xname, start, n, &tname);
/*
* We calculate the table index using the first
* character in the first label of tname.
*/
ch = tname.ndata[1];
i = tableindex[ch];
tlength = name_length(&tname);
toffset = (isc_uint16_t)(offset + (length - tlength));
if (toffset >= 0x4000)
break;
/*
* 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)
break;
}
node->count = cctx->count++;
/*
* 'node->r.base' becomes 'tmp' when start == 0.
* Record this by setting 0x8000 so it can be freed later.
*/
if (start == 0)
toffset |= 0x8000;
node->offset = toffset;
dns_name_toregion(&tname, &node->r);
dns_name_init(&node->name, NULL);
node->name.length = node->r.length;
node->name.ndata = node->r.base;
node->name.labels = tname.labels;
node->name.attributes = DNS_NAMEATTR_ABSOLUTE;
node->next = cctx->table[i];
cctx->table[i] = node;
start++;
n--;
count--;
}
if (start == 0)
isc_mem_put(cctx->mctx, tmp, length);
}
/*
* 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.
*/
isc_boolean_t
dns_compress_findglobal(dns_compress_t *cctx, const dns_name_t *name,
dns_name_t *prefix, isc_uint16_t *offset)
{
dns_name_t tname;
dns_compressnode_t *node = NULL;
unsigned int labels, i, n;
unsigned int numlabels;
unsigned char *p;
REQUIRE(VALID_CCTX(cctx));
REQUIRE(dns_name_isabsolute(name) == ISC_TRUE);
REQUIRE(offset != NULL);
if (ISC_UNLIKELY((cctx->allowed & DNS_COMPRESS_ENABLED) == 0))
return (ISC_FALSE);
if (cctx->count == 0)
return (ISC_FALSE);
labels = dns_name_countlabels(name);
INSIST(labels > 0);
dns_name_init(&tname, NULL);
numlabels = labels > 3U ? 3U : labels;
p = name->ndata;
for (n = 0; n < numlabels - 1; n++) {
unsigned char ch, llen;
unsigned int firstoffset, length;
firstoffset = (unsigned int)(p - name->ndata);
length = name->length - firstoffset;
/*
* We calculate the table index using the first
* character in the first label of the suffix name.
*/
ch = p[1];
i = tableindex[ch];
if (ISC_LIKELY((cctx->allowed &
DNS_COMPRESS_CASESENSITIVE) != 0))
{
for (node = cctx->table[i];
node != NULL;
node = node->next)
{
if (ISC_UNLIKELY(node->name.length != length))
continue;
if (ISC_LIKELY(memcmp(node->name.ndata,
p, length) == 0))
goto found;
}
} else {
for (node = cctx->table[i];
node != NULL;
node = node->next)
{
unsigned int l, count;
unsigned char c;
unsigned char *label1, *label2;
if (ISC_UNLIKELY(node->name.length != length))
continue;
l = labels - n;
if (ISC_UNLIKELY(node->name.labels != l))
continue;
label1 = node->name.ndata;
label2 = p;
while (ISC_LIKELY(l-- > 0)) {
count = *label1++;
if (count != *label2++)
goto cont1;
/* no bitstring support */
INSIST(count <= 63);
/* Loop unrolled for performance */
while (ISC_LIKELY(count > 3)) {
c = maptolower[label1[0]];
if (c != maptolower[label2[0]])
goto cont1;
c = maptolower[label1[1]];
if (c != maptolower[label2[1]])
goto cont1;
c = maptolower[label1[2]];
if (c != maptolower[label2[2]])
goto cont1;
c = maptolower[label1[3]];
if (c != maptolower[label2[3]])
goto cont1;
count -= 4;
label1 += 4;
label2 += 4;
}
while (ISC_LIKELY(count-- > 0)) {
c = maptolower[*label1++];
if (c != maptolower[*label2++])
goto cont1;
}
}
break;
cont1:
continue;
}
}
if (node != NULL)
break;
llen = *p;
p += llen + 1;
}
found:
/*
* If node == NULL, we found no match at all.
*/
if (node == NULL)
return (ISC_FALSE);
if (n == 0)
dns_name_reset(prefix);
else
dns_name_getlabelsequence(name, 0, n, prefix);
*offset = (node->offset & 0x7fff);
return (ISC_TRUE);
}
void
dns_compress_disable(dns_compress_t *cctx) {
REQUIRE(VALID_CCTX(cctx));
cctx->allowed &= ~DNS_COMPRESS_ENABLED;
}
