1 files changed, 341 insertions, 0 deletions
diff --git a/lib/dns/compress.c b/lib/dns/compress.c
new file mode 100644
index 0000000..11473ee
--- /dev/null
+++ b/lib/dns/compress.c
@@ -0,0 +1,341 @@
+/*
+ * Copyright (C) 2004-2007  Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (C) 1999-2001  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: compress.c,v 1.59 2007/06/19 23:47:16 tbox Exp $ */
+
+/*! \file */
+
+#define DNS_NAME_USEINLINE 1
+
+#include <config.h>
+
+#include <isc/mem.h>
+#include <isc/string.h>
+#include <isc/util.h>
+
+#include <dns/compress.h>
+#include <dns/fixedname.h>
+#include <dns/rbt.h>
+#include <dns/result.h>
+
+#define CCTX_MAGIC	ISC_MAGIC('C', 'C', 'T', 'X')
+#define VALID_CCTX(x)	ISC_MAGIC_VALID(x, CCTX_MAGIC)
+
+#define DCTX_MAGIC	ISC_MAGIC('D', 'C', 'T', 'X')
+#define VALID_DCTX(x)	ISC_MAGIC_VALID(x, DCTX_MAGIC)
+
+/***
+ ***	Compression
+ ***/
+
+isc_result_t
+dns_compress_init(dns_compress_t *cctx, int edns, isc_mem_t *mctx) {
+	unsigned int i;
+
+	REQUIRE(cctx != NULL);
+	REQUIRE(mctx != NULL);	/* See: rdataset.c:towiresorted(). */
+
+	cctx->allowed = 0;
+	cctx->edns = edns;
+	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;
+	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;
+}
+
+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);
+}
+
+unsigned int
+dns_compress_getmethods(dns_compress_t *cctx) {
+	REQUIRE(VALID_CCTX(cctx));
+	return (cctx->allowed & DNS_COMPRESS_ALL);
+}
+
+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;
+}
+
+isc_boolean_t
+dns_compress_getsensitive(dns_compress_t *cctx) {
+	REQUIRE(VALID_CCTX(cctx));
+
+	return (ISC_TF((cctx->allowed & DNS_COMPRESS_CASESENSITIVE) != 0));
+}
+
+int
+dns_compress_getedns(dns_compress_t *cctx) {
+	REQUIRE(VALID_CCTX(cctx));
+	return (cctx->edns);
+}
+
+#define NODENAME(node, name) \
+do { \
+	(name)->length = (node)->r.length; \
+	(name)->labels = (node)->labels; \
+	(name)->ndata = (node)->r.base; \
+	(name)->attributes = DNS_NAMEATTR_ABSOLUTE; \
+} while (0)
+
+/*
+ * 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);
+}
+
+static inline unsigned int
+name_length(const dns_name_t *name) {
+	isc_region_t r;
+	dns_name_toregion(name, &r);
+	return (r.length);
+}
+
+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--;
+	}
+}
+
+void
+dns_compress_rollback(dns_compress_t *cctx, isc_uint16_t offset) {
+	unsigned int i;
+	dns_compressnode_t *node;
+
+	REQUIRE(VALID_CCTX(cctx));
+
+	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 >= offset) {
+			cctx->table[i] = node->next;
+			if (node->count >= DNS_COMPRESS_INITIALNODES)
+				isc_mem_put(cctx->mctx, node, sizeof(*node));
+			cctx->count--;
+			node = cctx->table[i];
+		}
+	}
+}
+
+/***
+ ***	Decompression
+ ***/
+
+void
+dns_decompress_init(dns_decompress_t *dctx, int edns,
+		    dns_decompresstype_t type) {
+
+	REQUIRE(dctx != NULL);
+	REQUIRE(edns >= -1 && edns <= 255);
+
+	dctx->allowed = DNS_COMPRESS_NONE;
+	dctx->edns = edns;
+	dctx->type = type;
+	dctx->magic = DCTX_MAGIC;
+}
+
+void
+dns_decompress_invalidate(dns_decompress_t *dctx) {
+
+	REQUIRE(VALID_DCTX(dctx));
+
+	dctx->magic = 0;
+}
+
+void
+dns_decompress_setmethods(dns_decompress_t *dctx, unsigned int allowed) {
+
+	REQUIRE(VALID_DCTX(dctx));
+
+	switch (dctx->type) {
+	case DNS_DECOMPRESS_ANY:
+		dctx->allowed = DNS_COMPRESS_ALL;
+		break;
+	case DNS_DECOMPRESS_NONE:
+		dctx->allowed = DNS_COMPRESS_NONE;
+		break;
+	case DNS_DECOMPRESS_STRICT:
+		dctx->allowed = allowed;
+		break;
+	}
+}
+
+unsigned int
+dns_decompress_getmethods(dns_decompress_t *dctx) {
+
+	REQUIRE(VALID_DCTX(dctx));
+
+	return (dctx->allowed);
+}
+
+int
+dns_decompress_edns(dns_decompress_t *dctx) {
+
+	REQUIRE(VALID_DCTX(dctx));
+
+	return (dctx->edns);
+}
+
+dns_decompresstype_t
+dns_decompress_type(dns_decompress_t *dctx) {
+
+	REQUIRE(VALID_DCTX(dctx));
+
+	return (dctx->type);
+}