405. [func] Add support for selective forwarding (forward zones)

lib/dns/forward.c

@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2000  Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM
+ * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ * INTERNET SOFTWARE CONSORTIUM 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: forward.c,v 1.1 2000/08/24 22:15:30 bwelling Exp $ */
+
+#include <config.h>
+
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/rwlock.h>
+#include <isc/sockaddr.h>
+#include <isc/util.h>
+
+#include <dns/forward.h>
+#include <dns/rbt.h>
+#include <dns/result.h>
+#include <dns/types.h>
+
+struct dns_fwdtable {
+	/* Unlocked. */
+        unsigned int		magic;
+	isc_mem_t		*mctx;
+	isc_rwlock_t		rwlock;
+	/* Locked by lock. */
+	dns_rbt_t		*table;
+};
+
+#define FWDTABLEMAGIC		0x46776454U	/* FwdT */
+#define VALID_FWDTABLE(ft) 	ISC_MAGIC_VALID(ft, FWDTABLEMAGIC)
+
+static void
+auto_detach(void *, void *);
+
+isc_result_t
+dns_fwdtable_create(isc_mem_t *mctx, dns_fwdtable_t **fwdtablep) {
+	dns_fwdtable_t *fwdtable;
+	isc_result_t result;
+
+	REQUIRE(fwdtablep != NULL && *fwdtablep == NULL);
+
+	fwdtable = isc_mem_get(mctx, sizeof(dns_fwdtable_t));
+	if (fwdtable == NULL)
+		return (ISC_R_NOMEMORY);
+
+	fwdtable->table = NULL;
+	result = dns_rbt_create(mctx, auto_detach, fwdtable, &fwdtable->table);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup_fwdtable;
+
+	result = isc_rwlock_init(&fwdtable->rwlock, 0, 0);
+	if (result != ISC_R_SUCCESS) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "isc_rwlock_init() failed: %s",
+				 isc_result_totext(result));
+		result = ISC_R_UNEXPECTED;
+		goto cleanup_rbt;
+	}
+
+	fwdtable->mctx = NULL;
+	isc_mem_attach(mctx, &fwdtable->mctx);
+	fwdtable->magic = FWDTABLEMAGIC;
+	*fwdtablep = fwdtable;
+
+	return (ISC_R_SUCCESS);
+
+   cleanup_rbt:
+	dns_rbt_destroy(&fwdtable->table);
+
+   cleanup_fwdtable:
+	isc_mem_put(mctx, fwdtable, sizeof(dns_fwdtable_t));
+
+	return (result);
+}
+
+isc_result_t
+dns_fwdtable_add(dns_fwdtable_t *fwdtable, dns_name_t *name,
+		 isc_sockaddrlist_t *addrs, dns_fwdpolicy_t fwdpolicy)
+{
+	isc_result_t result;
+	dns_forwarders_t *forwarders;
+	isc_sockaddr_t *sa, *nsa;
+
+	REQUIRE(VALID_FWDTABLE(fwdtable));
+
+	forwarders = isc_mem_get(fwdtable->mctx, sizeof(dns_forwarders_t));
+	if (forwarders == NULL)
+		return (ISC_R_NOMEMORY);
+
+	ISC_LIST_INIT(forwarders->addrs);
+	for (sa = ISC_LIST_HEAD(*addrs);
+	     sa != NULL;
+	     sa = ISC_LIST_NEXT(sa, link))
+	{
+		nsa = isc_mem_get(fwdtable->mctx, sizeof(isc_sockaddr_t));
+		if (nsa == NULL) {
+			result = ISC_R_NOMEMORY;
+			goto cleanup;
+		}
+		*nsa = *sa;
+		ISC_LINK_INIT(nsa, link);
+		ISC_LIST_APPEND(forwarders->addrs, nsa, link);
+	}
+	forwarders->fwdpolicy = fwdpolicy;
+
+        RWLOCK(&fwdtable->rwlock, isc_rwlocktype_write);
+	result = dns_rbt_addname(fwdtable->table, name, forwarders);
+	RWUNLOCK(&fwdtable->rwlock, isc_rwlocktype_write);
+
+	if (result != ISC_R_SUCCESS)
+		goto cleanup;
+
+	return (ISC_R_SUCCESS);
+
+ cleanup:
+	while (!ISC_LIST_EMPTY(forwarders->addrs)) {
+		sa = ISC_LIST_HEAD(forwarders->addrs);
+		ISC_LIST_UNLINK(forwarders->addrs, sa, link);
+		isc_mem_put(fwdtable->mctx, sa, sizeof(isc_sockaddr_t));
+	}
+	isc_mem_put(fwdtable->mctx, forwarders, sizeof(dns_forwarders_t));
+	return (result);
+}
+
+isc_result_t
+dns_fwdtable_find(dns_fwdtable_t *fwdtable, dns_name_t *name,
+		  dns_forwarders_t **forwardersp)
+{
+	isc_result_t result;
+
+	REQUIRE(VALID_FWDTABLE(fwdtable));
+
+	RWLOCK(&fwdtable->rwlock, isc_rwlocktype_read);
+
+	result = dns_rbt_findname(fwdtable->table, name, 0, NULL,
+				  (void **)forwardersp);
+	if (result == DNS_R_PARTIALMATCH)
+		result = ISC_R_SUCCESS;
+
+	RWUNLOCK(&fwdtable->rwlock, isc_rwlocktype_read);
+
+	return (result);
+}
+
+void
+dns_fwdtable_destroy(dns_fwdtable_t **fwdtablep) {
+	dns_fwdtable_t *fwdtable;
+	isc_mem_t *mctx = mctx;
+
+	REQUIRE(fwdtablep != NULL && VALID_FWDTABLE(*fwdtablep));
+
+	fwdtable = *fwdtablep;
+
+	dns_rbt_destroy(&fwdtable->table);
+	isc_rwlock_destroy(&fwdtable->rwlock);
+	fwdtable->magic = 0;
+	mctx = fwdtable->mctx;
+	isc_mem_put(mctx, fwdtable, sizeof(dns_fwdtable_t));
+	isc_mem_detach(&mctx);
+
+	*fwdtablep = NULL;
+}
+
+/***
+ *** Private
+ ***/
+
+static void
+auto_detach(void *data, void *arg) {
+	dns_forwarders_t *forwarders = data;
+	dns_fwdtable_t *fwdtable = arg;
+	isc_sockaddr_t *sa;
+
+	UNUSED(arg);
+
+	while (!ISC_LIST_EMPTY(forwarders->addrs)) {
+		sa = ISC_LIST_HEAD(forwarders->addrs);
+		ISC_LIST_UNLINK(forwarders->addrs, sa, link);
+		isc_mem_put(fwdtable->mctx, sa, sizeof(isc_sockaddr_t));
+	}
+	isc_mem_put(fwdtable->mctx, forwarders, sizeof(dns_forwarders_t));
+}