| /* |
| * Copyright (C) 2017 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 NETLINK_LISTENER_H |
| #define NETLINK_LISTENER_H |
| |
| #include <functional> |
| #include <map> |
| #include <mutex> |
| #include <thread> |
| |
| #include <android-base/thread_annotations.h> |
| #include <netdutils/Netlink.h> |
| #include <netdutils/Slice.h> |
| #include <netdutils/Status.h> |
| #include <netdutils/UniqueFd.h> |
| |
| namespace android { |
| namespace net { |
| |
| class NetlinkListenerInterface { |
| public: |
| using DispatchFn = std::function<void(const nlmsghdr& nlmsg, const netdutils::Slice msg)>; |
| |
| using SkErrorHandler = std::function<void(const int fd, const int err)>; |
| |
| virtual ~NetlinkListenerInterface() = default; |
| |
| // Send message to the kernel using the underlying netlink socket |
| virtual netdutils::Status send(const netdutils::Slice msg) = 0; |
| |
| // Deliver future messages with nlmsghdr.nlmsg_type == type to fn. |
| // |
| // Threadsafe. |
| // All dispatch functions invoked on a single service thread. |
| // subscribe() and join() must not be called from the stack of fn(). |
| virtual netdutils::Status subscribe(uint16_t type, const DispatchFn& fn) = 0; |
| |
| // Halt delivery of future messages with nlmsghdr.nlmsg_type == type. |
| // Threadsafe. |
| virtual netdutils::Status unsubscribe(uint16_t type) = 0; |
| |
| virtual void registerSkErrorHandler(const SkErrorHandler& handler) = 0; |
| }; |
| |
| // NetlinkListener manages a netlink socket and associated blocking |
| // service thread. |
| // |
| // This class is written in a generic way to allow multiple different |
| // netlink subsystems to share this common infrastructure. If multiple |
| // subsystems share the same message delivery requirements (drops ok, |
| // no drops) they may share a single listener by calling subscribe() |
| // with multiple types. |
| // |
| // This class is suitable for moderate performance message |
| // processing. In particular it avoids extra copies of received |
| // message data and allows client code to control which message |
| // attributes are processed. |
| // |
| // Note that NetlinkListener is capable of processing multiple batched |
| // netlink messages in a single system call. This is useful to |
| // netfilter extensions that allow batching of events like NFLOG. |
| class NetlinkListener : public NetlinkListenerInterface { |
| public: |
| NetlinkListener(netdutils::UniqueFd event, netdutils::UniqueFd sock, const std::string& name); |
| |
| ~NetlinkListener() override; |
| |
| netdutils::Status send(const netdutils::Slice msg) override; |
| |
| netdutils::Status subscribe(uint16_t type, const DispatchFn& fn) override EXCLUDES(mMutex); |
| |
| netdutils::Status unsubscribe(uint16_t type) override EXCLUDES(mMutex); |
| |
| void registerSkErrorHandler(const SkErrorHandler& handler) override; |
| |
| private: |
| netdutils::Status run(); |
| |
| const netdutils::UniqueFd mEvent; |
| const netdutils::UniqueFd mSock; |
| const std::string mThreadName; |
| std::mutex mMutex; |
| std::map<uint16_t, DispatchFn> mDispatchMap GUARDED_BY(mMutex); |
| std::thread mWorker; |
| SkErrorHandler mErrorHandler; |
| }; |
| |
| } // namespace net |
| } // namespace android |
| |
| #endif /* NETLINK_LISTENER_H */ |