Merge libnetddns into libnetd_resolv
libnetddns is the library for DNS-over-TLS and is statically
linked to netd. Deprecate it and move them to libnetd_resolv
as a more general DNS library for netd.
This change comprises:
[1] Clean up netd/server/dns/*. Move all DnsTls* files to
netd/resolv/ to parts of libnetd_resolv library.
[2] Export DnsTls* classes being visible for netd. It will only
be temporary for a while.
[3] Remove the libssl dependency in netd. The relevant stuff is
moved to libnetd_resolv.
Note that DnsTls* classes are still required for DnsProxyListener
and ResolverController to manipulate private DNS servers even after
this change.
Bug: 113628807
Test: as follows
- built, flashed, booted
- system/netd/tests/runtests.sh
- DNS-over-TLS in live network passed
Change-Id: Ieac5889b4ebe737f876b3dcbe1a8da2b2b1b629d
diff --git a/resolv/include/netd_resolv/DnsTlsQueryMap.h b/resolv/include/netd_resolv/DnsTlsQueryMap.h
new file mode 100644
index 0000000..4c8010c
--- /dev/null
+++ b/resolv/include/netd_resolv/DnsTlsQueryMap.h
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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 _DNS_DNSTLSQUERYMAP_H
+#define _DNS_DNSTLSQUERYMAP_H
+
+#include <future>
+#include <map>
+#include <mutex>
+#include <vector>
+
+#include <android-base/thread_annotations.h>
+#include <netdutils/Slice.h>
+
+#include "DnsTlsServer.h"
+#include "params.h"
+
+namespace android {
+namespace net {
+
+using netdutils::Slice;
+
+// Keeps track of queries and responses. This class matches responses with queries.
+// All methods are thread-safe and non-blocking.
+class LIBNETD_RESOLV_TLS_EXPORT DnsTlsQueryMap {
+public:
+ struct Query {
+ // The new ID number assigned to this query.
+ uint16_t newId;
+ // A query that has been passed to recordQuery(), with its original ID number.
+ const Slice query;
+ };
+
+ typedef DnsTlsServer::Response Response;
+ typedef DnsTlsServer::Result Result;
+
+ struct QueryFuture {
+ QueryFuture(Query query, std::future<Result> result) :
+ query(query), result(std::move(result)) {}
+ Query query;
+ // A future which will resolve to the result of this query.
+ std::future<Result> result;
+ };
+
+ // Returns an object containing everything needed to complete processing of
+ // this query, or null if the query could not be recorded.
+ std::unique_ptr<QueryFuture> recordQuery(const Slice query);
+
+ // Process a response, including a new ID. If the response
+ // is not recognized as matching any query, it will be ignored.
+ void onResponse(std::vector<uint8_t> response);
+
+ // Clear all map contents. This causes all pending queries to resolve with failure.
+ void clear();
+
+ // Get all pending queries. This returns a shallow copy, mostly for thread-safety.
+ std::vector<Query> getAll();
+
+ // Mark a query has having been retried. If the query hits the retry limit, it will
+ // be expired at the next call to cleanup.
+ void markTried(uint16_t newId);
+ void cleanup();
+
+ // Returns true if there are no pending queries.
+ bool empty();
+
+private:
+ std::mutex mLock;
+
+ struct QueryPromise {
+ QueryPromise(Query query) : query(query) {}
+ Query query;
+ // Number of times the query has been tried. Limited to kMaxTries.
+ int tries = 0;
+ // A promise whose future is returned by recordQuery()
+ // It is fulfilled by onResponse().
+ std::promise<Result> result;
+ };
+
+ // The maximum number of times we will send a query before abandoning it.
+ static constexpr int kMaxTries = 3;
+
+ // Outstanding queries by newId.
+ std::map<uint16_t, QueryPromise> mQueries GUARDED_BY(mLock);
+
+ // Get a "newId" number that is not currently in use. Returns -1 if there are none.
+ int32_t getFreeId() REQUIRES(mLock);
+
+ // Fulfill the result with an error code.
+ static void expire(QueryPromise* _Nonnull p);
+};
+
+} // end of namespace net
+} // end of namespace android
+
+#endif // _DNS_DNSTLSQUERYMAP_H