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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.
     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