1 /*
2  * Copyright (C) 2019 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 #include "NetlinkRequest.h"
20 
21 #include <android-base/macros.h>
22 #include <android-base/unique_fd.h>
23 
24 #include <linux/netlink.h>
25 
26 namespace android::netdevice {
27 
28 /**
29  * A wrapper around AF_NETLINK sockets.
30  *
31  * This class is not thread safe to use a single instance between multiple threads, but it's fine to
32  * use multiple instances over multiple threads.
33  */
34 struct NetlinkSocket {
35     NetlinkSocket(int protocol);
36 
37     /**
38      * Send Netlink message to Kernel.
39      *
40      * \param msg Message to send, nlmsg_seq will be set to next sequence number
41      * \return true, if succeeded
42      */
43     template <class T, unsigned int BUFSIZE>
sendNetlinkSocket44     bool send(NetlinkRequest<T, BUFSIZE>& req) {
45         if (!req.isGood()) return false;
46         return send(req.header());
47     }
48 
49     /**
50      * Receive Netlink ACK message from Kernel.
51      *
52      * \return true if received ACK message, false in case of error
53      */
54     bool receiveAck();
55 
56   private:
57     uint32_t mSeq = 0;
58     base::unique_fd mFd;
59     bool mFailed = false;
60 
61     bool send(struct nlmsghdr* msg);
62 
63     DISALLOW_COPY_AND_ASSIGN(NetlinkSocket);
64 };
65 
66 }  // namespace android::netdevice
67