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.
47class 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.
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.
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