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1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 // This file provides a class interface for cross-platform socket functionality. The main fastboot
30 // engine should not be using this interface directly, but instead should use a higher-level
31 // interface that enforces the fastboot protocol.
32 
33 #ifndef SOCKET_H_
34 #define SOCKET_H_
35 
36 #include <functional>
37 #include <memory>
38 #include <string>
39 #include <utility>
40 #include <vector>
41 
42 #include <android-base/macros.h>
43 #include <cutils/sockets.h>
44 #include <gtest/gtest_prod.h>
45 
46 // Socket interface to be implemented for each platform.
47 class Socket {
48   public:
49     enum class Protocol { kTcp, kUdp };
50 
51     // Returns the socket error message. This must be called immediately after a socket failure
52     // before any other system calls are made.
53     static std::string GetErrorMessage();
54 
55     // Creates a new client connection. Clients are connected to a specific hostname/port and can
56     // only send to that destination.
57     // On failure, |error| is filled (if non-null) and nullptr is returned.
58     static std::unique_ptr<Socket> NewClient(Protocol protocol, const std::string& hostname,
59                                              int port, std::string* error);
60 
61     // Creates a new server bound to local |port|. This is only meant for testing, during normal
62     // fastboot operation the device acts as the server.
63     // A UDP server saves sender addresses in Receive(), and uses the most recent address during
64     // calls to Send().
65     static std::unique_ptr<Socket> NewServer(Protocol protocol, int port);
66 
67     // Destructor closes the socket if it's open.
68     virtual ~Socket();
69 
70     // Sends |length| bytes of |data|. For TCP sockets this will continue trying to send until all
71     // bytes are transmitted. Returns true on success.
72     virtual bool Send(const void* data, size_t length) = 0;
73 
74     // Sends |buffers| using multi-buffer write, which can be significantly faster than making
75     // multiple calls. For UDP sockets |buffers| are all combined into a single datagram; for
76     // TCP sockets this will continue sending until all buffers are fully transmitted. Returns true
77     // on success.
78     //
79     // Note: This is non-functional for UDP server Sockets because it's not currently needed and
80     // would require an additional sendto() variation of multi-buffer write.
81     virtual bool Send(std::vector<cutils_socket_buffer_t> buffers) = 0;
82 
83     // Waits up to |timeout_ms| to receive up to |length| bytes of data. |timout_ms| of 0 will
84     // block forever. Returns the number of bytes received or -1 on error/timeout; see
85     // ReceiveTimedOut() to distinguish between the two.
86     virtual ssize_t Receive(void* data, size_t length, int timeout_ms) = 0;
87 
88     // Calls Receive() until exactly |length| bytes have been received or an error occurs.
89     virtual ssize_t ReceiveAll(void* data, size_t length, int timeout_ms);
90 
91     // Returns true if the last Receive() call timed out normally and can be retried; fatal errors
92     // or successful reads will return false.
ReceiveTimedOut()93     bool ReceiveTimedOut() { return receive_timed_out_; }
94 
95     // Closes the socket. Returns 0 on success, -1 on error.
96     virtual int Close();
97 
98     // Accepts an incoming TCP connection. No effect for UDP sockets. Returns a new Socket
99     // connected to the client on success, nullptr on failure.
Accept()100     virtual std::unique_ptr<Socket> Accept() { return nullptr; }
101 
102     // Returns the local port the Socket is bound to or -1 on error.
103     int GetLocalPort();
104 
105   protected:
106     // Protected constructor to force factory function use.
107     explicit Socket(cutils_socket_t sock);
108 
109     // Blocks up to |timeout_ms| until a read is possible on |sock_|, and sets |receive_timed_out_|
110     // as appropriate to help distinguish between normal timeouts and fatal errors. Returns true if
111     // a subsequent recv() on |sock_| will complete without blocking or if |timeout_ms| <= 0.
112     bool WaitForRecv(int timeout_ms);
113 
114     cutils_socket_t sock_ = INVALID_SOCKET;
115     bool receive_timed_out_ = false;
116 
117     // Non-class functions we want to override during tests to verify functionality. Implementation
118     // should call this rather than using socket_send_buffers() directly.
119     std::function<ssize_t(cutils_socket_t, cutils_socket_buffer_t*, size_t)>
120             socket_send_buffers_function_ = &socket_send_buffers;
121 
122   private:
123     FRIEND_TEST(SocketTest, TestTcpSendBuffers);
124     FRIEND_TEST(SocketTest, TestUdpSendBuffers);
125 
126     DISALLOW_COPY_AND_ASSIGN(Socket);
127 };
128 
129 #endif  // SOCKET_H_
130