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authorDave Barach <dave@barachs.net>2017-10-10 17:53:14 -0400
committerFlorin Coras <florin.coras@gmail.com>2017-10-13 20:20:09 +0000
commit6545716c073c88ad86458620c6dbc59ba1cd00bb (patch)
tree2bd8b7d9cd0e221669081aba27786e1ce5eee964 /src/vnet/dns/dns.h
parent7e550693dffd368b9dd8e0397674cfc4d10f9579 (diff)
VPP-1027: DNS name resolver
This patch is a plausible first-cut, suitable for initial testing by vcl (host stack client library). Main features; - recursive name resolution - multiple ip4/ip6 name servers - cache size limit enforcement - currently limited to 65K - ttl / aging - static mapping support - show / clear / debug CLI commands Binary APIs provided for the following: - add/delete name servers - enable/disable the name cache - resolve a name To Do list: - Respond to ip4/ip6 client DNS requests (vs. binary API requests) - Perf / scale tuning - map pending transaction ids to pool indices, so the cache can (greatly) exceed 65K entries - Security improvements - Use unpredictable dns transaction IDs, related to previous item - Make sure that response-packet src ip addresses match the server - Add binary APIs - deliver raw response data to clients - control recursive name resolution - Documentation Change-Id: I48c373d5c05d7108ccd814d4055caf8c75ca10b7 Signed-off-by: Dave Barach <dave@barachs.net>
Diffstat (limited to 'src/vnet/dns/dns.h')
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1 files changed, 149 insertions, 0 deletions
diff --git a/src/vnet/dns/dns.h b/src/vnet/dns/dns.h
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+++ b/src/vnet/dns/dns.h
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+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef included_dns_h
+#define included_dns_h
+
+#include <vppinfra/time.h>
+#include <vppinfra/cache.h>
+#include <vppinfra/error.h>
+
+#include <vppinfra/hash.h>
+#include <vnet/dns/dns_packet.h>
+#include <vnet/ip/ip.h>
+
+typedef struct
+{
+ /** flags */
+ volatile u8 flags;
+
+ /** The name in "normal human being" notation, e.g. www.foobar.com */
+ u8 *name;
+
+ /** Expiration time */
+ f64 expiration_time;
+
+ /** Cached dns request, for sending retries */
+ u8 *dns_request;
+
+ /** Retry parameters */
+ int retry_count;
+ int server_rotor;
+ int server_af;
+ f64 retry_timer;
+
+ /** Cached dns response */
+ u8 *dns_response;
+
+ /** Clients awaiting responses */
+ u32 *api_clients_to_notify;
+ u32 *api_client_contexts;
+ ip4_address_t *ip4_peers_to_notify;
+ ip6_address_t *ip6_peers_to_notify;
+} dns_cache_entry_t;
+
+#define DNS_CACHE_ENTRY_FLAG_VALID (1<<0) /**< we have Actual Data */
+#define DNS_CACHE_ENTRY_FLAG_STATIC (1<<1) /**< static entry */
+
+#define DNS_RETRIES_PER_SERVER 3
+
+#define DNS_RESOLVER_EVENT_RESOLVED 1
+#define DNS_RESOLVER_EVENT_PENDING 2
+
+
+typedef struct
+{
+ /** Pool of cache entries */
+ dns_cache_entry_t *entries;
+
+ /** Pool indices of unresolved entries */
+ u32 *unresolved_entries;
+
+ /** Find cached record by name */
+ uword *cache_entry_by_name;
+ uword *cache_lock;
+
+ /** enable / disable flag */
+ int is_enabled;
+
+ /** upstream name servers, e.g. 8.8.8.8 */
+ ip4_address_t *ip4_name_servers;
+ ip6_address_t *ip6_name_servers;
+
+ /** config parameters */
+ u32 name_cache_size;
+ u32 max_ttl_in_seconds;
+ u32 random_seed;
+
+ /* convenience */
+ vlib_main_t *vlib_main;
+ vnet_main_t *vnet_main;
+} dns_main_t;
+
+extern dns_main_t dns_main;
+
+extern vlib_node_registration_t dns46_reply_node;
+extern vlib_node_registration_t dns_resolver_node;
+
+#define foreach_dns46_reply_error \
+_(PROCESSED, "DNS reply pkts processed") \
+_(NO_ELT, "No DNS pool element") \
+_(FORMAT_ERROR, "DNS format errors") \
+_(TEST_DROP, "DNS reply pkt dropped for test purposes")
+
+typedef enum
+{
+#define _(sym,str) DNS46_REPLY_ERROR_##sym,
+ foreach_dns46_reply_error
+#undef _
+ DNS46_REPLY_N_ERROR,
+} dns46_reply_error_t;
+
+void vnet_send_dns_request (dns_main_t * dm, dns_cache_entry_t * ep);
+int vnet_dns_cname_indirection_nolock (dns_main_t * dm,
+ dns_cache_entry_t * ep, u8 * reply);
+int vnet_dns_delete_entry_by_index_nolock (dns_main_t * dm, u32 index);
+
+format_function_t format_dns_reply;
+
+static inline void
+dns_cache_lock (dns_main_t * dm)
+{
+ if (dm->cache_lock)
+ {
+ while (__sync_lock_test_and_set (dm->cache_lock, 1))
+ ;
+ }
+}
+
+static inline void
+dns_cache_unlock (dns_main_t * dm)
+{
+ if (dm->cache_lock)
+ {
+ CLIB_MEMORY_BARRIER ();
+ *dm->cache_lock = 0;
+ }
+}
+
+#endif /* included_dns_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */