通过套接字发送文件太慢了

Question

我是新来的（我的第一个问题）和一点新手，我从未有过编程课程，所以...对于一些混乱的代码感到抱歉。

我制作了这个程序，通过套接字发送（客户端）和接收（服务器）文件，客户端每个循环读取并发送1024个字节的文件，服务器接收它并将其写入文件。它工作正常，但问题是它很慢。将文件从我的计算机发送到我的计算机需要花费同样多的时间作为发送到另一台计算机，但仍然需要比预期更多的时间，当我尝试转移时，例如，通过Skype，它的速度要快得多。任何线索？ （下面是我正在使用的代码。）

服务器：

// servrecvfile.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#undef UNICODE

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>

// Need to link with Ws2_32.lib
#pragma comment (lib, "Ws2_32.lib")
// #pragma comment (lib, "Mswsock.lib")

#define DEFAULT_BUFLEN 65536
#define DEFAULT_PORT "8883"

typedef struct thread_args{
    SOCKET ClientSocket;
    int index;
} *MYDATA, PM;

MYDATA pDataArray[100];
DWORD WINAPI abc(void*);

int p=0;

int abz(){
    return p;
}

void broadcast(MYDATA *fp, char *b, int index){
    for(int i=0; i<=abz(); i++){
        if(index != i)
            send( fp[i]->ClientSocket, b, (int)strlen(b), 0 );
    }
}

DWORD WINAPI abc(void* pVoid)
{   
    struct thread_args *fp;
    fp = (struct thread_args *) pVoid;
    long iResult;
    int filesize;
    unsigned char recvbuf[ DEFAULT_BUFLEN];
    memset(recvbuf, 0, sizeof(recvbuf));
    recv(fp->ClientSocket, (char*)recvbuf,  DEFAULT_BUFLEN, 0);
    FILE *abc = fopen(strtok ((char*)recvbuf,":"), "wb");
    filesize = atoi(strtok (NULL,":"));
    memset(recvbuf, 0, sizeof(recvbuf));
    int perc=0;
    int perc2=0;
    int counter=0;
    char a = '%';
        do {
            iResult = recv(fp->ClientSocket, (char*)recvbuf,  DEFAULT_BUFLEN, 0);
            if (iResult > 0) {
                counter += fwrite (recvbuf , sizeof(char) , iResult , abc );
                memset(recvbuf, 0, sizeof(recvbuf));
                perc2 = ((counter*1.000)/filesize*1.000)*100;
                if(perc2 != perc){
                    printf("%d%c\n", perc2, a);
                    perc = perc2;
                } 
            }
            else if (iResult == 0)
              printf("Connection closing...\n");
            else  {
              printf("recv failed with error: %d\n", WSAGetLastError());
              closesocket(fp->ClientSocket);
              fclose(abc);
              WSACleanup();
              ExitThread(1);
            }
        } while (iResult > 0);


        fclose(abc);
       ExitThread(-1);
}

int __cdecl main(void) 
{
    WSADATA wsaData;
    int iResult;

    SOCKET ListenSocket = INVALID_SOCKET;
    SOCKET ClientSocket = INVALID_SOCKET;

    struct addrinfo *result = NULL;
    struct addrinfo hints;

    int iSendResult;
    char recvbuf[DEFAULT_BUFLEN];
    int recvbuflen = DEFAULT_BUFLEN;


    // Initialize Winsock
    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0) {
        printf("WSAStartup failed with error: %d\n", iResult);
        return 1;
    }

    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags = AI_PASSIVE;

    // Resolve the server address and port
    iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
    if ( iResult != 0 ) {
        printf("getaddrinfo failed with error: %d\n", iResult);
        WSACleanup();
        return 1;
    }

    // Create a SOCKET for connecting to server
    ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    if (ListenSocket == INVALID_SOCKET) {
        printf("socket failed with error: %ld\n", WSAGetLastError());
        freeaddrinfo(result);
        WSACleanup();
        return 1;
    }

    // Setup the TCP listening socket
    iResult = bind( ListenSocket, result->ai_addr, (int)result->ai_addrlen);
    if (iResult == SOCKET_ERROR) {
        printf("bind failed with error: %d\n", WSAGetLastError());
        freeaddrinfo(result);
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    freeaddrinfo(result);

    iResult = listen(ListenSocket, SOMAXCONN);
    if (iResult == SOCKET_ERROR) {
        printf("listen failed with error: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }

    int i=0;
    while(1){

    // Accept a client socket
    ClientSocket = accept(ListenSocket, NULL, NULL);
    if (ClientSocket == INVALID_SOCKET) {
        printf("accept failed with error: %d\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }
    pDataArray[i] = (MYDATA) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY,
                sizeof(PM));
    pDataArray[i]->ClientSocket = ClientSocket;
    pDataArray[i]->index = i;

        CreateThread( 
            NULL,                   // default security attributes
            0,                      // use default stack size  
            abc,       // thread function name
            pDataArray[i],          // argument to thread function 
            0,                      // use default creation flags 
            NULL);   // returns the thread identifier 
        p = i;
        i++;
    }

    // No longer need server socket
    closesocket(ListenSocket);

    // Receive until the peer shuts down the connection
    //char a[DEFAULT_BUFLEN];





    // shutdown the connection since we're done
    iResult = shutdown(ClientSocket, SD_SEND);
    if (iResult == SOCKET_ERROR) {
        printf("shutdown failed with error: %d\n", WSAGetLastError());
        closesocket(ClientSocket);
        WSACleanup();
        return 1;
    }

    // cleanup
    closesocket(ClientSocket);
    WSACleanup();

    return 0;
}

客户端：

// sendfile.cpp : Defines the entry point for the console application.
//
#include "StdAfx.h"

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>


// Need to link with Ws2_32.lib, Mswsock.lib, and Advapi32.lib
#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")


#define DEFAULT_BUFLEN 65536
#define DEFAULT_PORT "8882"


int __cdecl main(int argc, char **argv) 
{
    WSADATA wsaData;
    SOCKET ConnectSocket = INVALID_SOCKET;
    struct addrinfo *result = NULL,
                    *ptr = NULL,
                    hints;
    char *sendbuf = "this is a test";
    char recvbuf[DEFAULT_BUFLEN];
    int iResult;
    int recvbuflen = DEFAULT_BUFLEN;

    char linha[DEFAULT_BUFLEN];
    char IP[20], porta[10];

    FILE *fp1;
    fp1 = fopen("config.txt", "r");
    if(fp1 == NULL)
    {
        printf("Unable to find config.txt.\n");
        exit(-1);
    }
    while( fgets(linha,DEFAULT_BUFLEN,  fp1) !=NULL){
        if(strstr(linha, "port="))
            sscanf(linha, "port=%s", porta);
        if(strstr(linha, "ip="))
            sscanf(linha, "ip=%s", IP);
    }

    fclose(fp1);


    char filenam[DEFAULT_BUFLEN];
    printf("Insert file name: ");
    scanf ("%s", filenam);
    FILE *trans = fopen(filenam, "rb");

    if(trans == NULL)
    {
        printf("File not found\n");
        exit(-1);
    }


    // Initialize Winsock
    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0) {
        printf("WSAStartup failed with error: %d\n", iResult);
        return 1;
    }

    ZeroMemory( &hints, sizeof(hints) );
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    // Resolve the server address and port
    iResult = getaddrinfo(IP, porta, &hints, &result);
    if ( iResult != 0 ) {
        printf("getaddrinfo failed with error: %d\n", iResult);
        WSACleanup();
        return 1;
    }

    // Attempt to connect to an address until one succeeds
    for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {

        // Create a SOCKET for connecting to server
        ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, 
            ptr->ai_protocol);
        if (ConnectSocket == INVALID_SOCKET) {
            printf("socket failed with error: %ld\n", WSAGetLastError());
            WSACleanup();
            return 1;
        }

        // Connect to server.
        iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
        if (iResult == SOCKET_ERROR) {
            closesocket(ConnectSocket);
            ConnectSocket = INVALID_SOCKET;
            continue;
        }
        break;
    }

    freeaddrinfo(result);

    if (ConnectSocket == INVALID_SOCKET) {
        printf("Unable to connect to server!\n");
        WSACleanup();
        return 1;
    }



    long lSize;

      // obtain file size:
    fseek (trans , 0 , SEEK_END);
    lSize = ftell (trans);
    rewind (trans);
    char a = '%';
  // allocate memory to contain the whole file:
    memset(recvbuf, 0, sizeof(recvbuf));
    unsigned char *linha2 = (unsigned char*) malloc (sizeof(unsigned char)* DEFAULT_BUFLEN);
    //send(ConnectSocket, filenam, (int)strlen(filenam), 0 );
    sprintf(filenam, "%s:%d", filenam, lSize);
    printf("%d %d\n", send(ConnectSocket, filenam, (int)strlen(filenam), 0 ), lSize);
    long counter=0;
    long read;
    int perc=0;
    int perc2=0;
    while(counter < lSize){
        read = fread_s(linha2,  DEFAULT_BUFLEN, sizeof(char),  DEFAULT_BUFLEN, trans);
        counter += send(ConnectSocket, (char*)linha2, read, 0);
        perc2 = ((counter*1.000)/lSize*1.000)*100;
        if(perc2 != perc){

            printf("%d%c\n", perc2, a);
            perc = perc2;
        } 

    }






    fclose(trans);
    /*
    do {
        //memset(a, 0, sizeof(a));
        iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
        if ( iResult > 0 )
        {
            printf("%s", recvbuf);
            memset(recvbuf, 0, sizeof(recvbuf));
        }
        else if ( iResult == 0 )
            printf("Connection closed\n");
        else
            printf("recv failed with error: %d\n", WSAGetLastError());


    } while( iResult > 0 ); */

    // cleanup
    closesocket(ConnectSocket);
    WSACleanup();

    return 0;
}

我在Windows 7上使用visual studio 2010。

感谢任何帮助，如果这个问题的结构有任何问题，请告诉我。

Answer 1

为了通过套接字有效地发送文件数据，Windows提供了TransmitFile功能。

Answer 2

Skype可能正在压缩该文件，这将大大加快网络传输速度。您可以使用zlib压缩内联，或者从许多公开的（Huffman编码等）中实现自己的内联。

BTW，改变缓冲区大小不会改变性能。底层API（文件，套接字）已经过优化，可以自动处理缓冲，而与您对它们的读/写方式无关。

Answer 3

首先运行Wireshark并获取网络通信的痕迹。我预计你会受到默认TCP窗口大小的影响而导致不必要的流量控制。

看看这些可能有帮助的答案：

• What are some good Wireshark tutorials?
• What are SO_SNDBUF and SO_RECVBUF
• How setting the recv buffer size affects TCP Windows Size.
• Why is my call to TransmitFile performing poorly compared to other methods?