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1 /*
2  * Copyright (C) 2016 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 #ifndef _SOCK_DIAG_H
18 #define _SOCK_DIAG_H
19 
20 #include <unistd.h>
21 #include <sys/socket.h>
22 
23 #include <linux/netlink.h>
24 #include <linux/sock_diag.h>
25 #include <linux/inet_diag.h>
26 
27 #include <functional>
28 #include <set>
29 
30 #include "Fwmark.h"
31 #include "NetlinkCommands.h"
32 #include "Permission.h"
33 #include "UidRanges.h"
34 
35 struct inet_diag_msg;
36 struct tcp_info;
37 class SockDiagTest;
38 
39 namespace android {
40 namespace net {
41 
42 class SockDiag {
43 
44   public:
45     static const int kBufferSize = 4096;
46 
47     // Callback function that is called once for every socket in the sockDestroy dump.
48     // A return value of true means destroy the socket.
49     typedef std::function<bool(uint8_t proto, const inet_diag_msg *)> DestroyFilter;
50 
51     // Callback function that is called once for every socket in the sockInfo dump.
52     // 'tcp_info_length' is the length in bytes of the INET_DIAG_INFO attribute read from Netlink.
53     // Knowing this length is necessary for handling struct tcp_info serialized from different
54     // kernel versions.
55     typedef std::function<void(Fwmark mark, const struct inet_diag_msg *, const struct tcp_info *,
56             uint32_t tcp_info_length)> TcpInfoReader;
57 
58     struct DestroyRequest {
59         nlmsghdr nlh;
60         inet_diag_req_v2 req;
61     } __attribute__((__packed__));
62 
SockDiag()63     SockDiag() : mSock(-1), mWriteSock(-1), mSocketsDestroyed(0) {}
64     bool open();
~SockDiag()65     virtual ~SockDiag() { closeSocks(); }
66 
67     int sendDumpRequest(uint8_t proto, uint8_t family, uint32_t states);
68     int sendDumpRequest(uint8_t proto, uint8_t family, const char *addrstr);
69     int readDiagMsg(uint8_t proto, const DestroyFilter& callback);
70     int readDiagMsgWithTcpInfo(const TcpInfoReader& callback);
71 
72     int sockDestroy(uint8_t proto, const inet_diag_msg *);
73     // Destroys all sockets on the given IPv4 or IPv6 address.
74     int destroySockets(const char *addrstr);
75     // Destroys all sockets for the given protocol and UID.
76     int destroySockets(uint8_t proto, uid_t uid, bool excludeLoopback);
77     // Destroys all "live" (CONNECTED, SYN_SENT, SYN_RECV) TCP sockets for the given UID ranges.
78     int destroySockets(const UidRanges& uidRanges, const std::set<uid_t>& skipUids,
79                        bool excludeLoopback);
80     // Destroys all "live" (CONNECTED, SYN_SENT, SYN_RECV) TCP sockets that no longer have
81     // the permissions required by the specified network.
82     int destroySocketsLackingPermission(unsigned netId, Permission permission,
83                                         bool excludeLoopback);
84 
85     // Dump struct tcp_info for all "live" (CONNECTED, SYN_SENT, SYN_RECV) TCP sockets.
86     int getLiveTcpInfos(const TcpInfoReader& sockInfoReader);
87 
88   private:
89     friend class SockDiagTest;
90     int mSock;
91     int mWriteSock;
92     int mSocketsDestroyed;
93     int sendDumpRequest(uint8_t proto, uint8_t family, uint8_t extensions, uint32_t states,
94                         iovec *iov, int iovcnt);
95     int destroySockets(uint8_t proto, int family, const char *addrstr);
96     int destroyLiveSockets(const DestroyFilter& destroy, const char *what, iovec *iov, int iovcnt);
hasSocks()97     bool hasSocks() { return mSock != -1 && mWriteSock != -1; }
closeSocks()98     void closeSocks() { close(mSock); close(mWriteSock); mSock = mWriteSock = -1; }
99     static bool isLoopbackSocket(const inet_diag_msg *msg);
100 };
101 
102 }  // namespace net
103 }  // namespace android
104 
105 #endif  // _SOCK_DIAG_H
106