Question

你好我基于msdn winsock2.h教程制作了这个程序。我有服务器程序和客户端一个。一切正常，我甚至从服务器到客户端进行单向聊天，更像是广播。现在我想要当他连接时看到客户端的IP地址。我想我做对了，但是，在每个连接上它都显示不同的地址，如12.2.90.0然后，12.2.46.0。

这是服务器代码：

#include <cstdlib>
#include <iostream>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <iphlpapi.h>
#define DEFAULT_PORT "27015"

using namespace std;


int main(int argc, char *argv[])
{



    WSADATA wsaData;
    int iResult;

    SOCKET ListenSocket = INVALID_SOCKET;
    SOCKET ClientSocket = INVALID_SOCKET;

    struct sockaddr_in client_info;
    char * addr;


    struct addrinfo *result = NULL;
    struct addrinfo hints;

    int iSendResult;
    char buffer[50];
    char typebuffer[50];
    char connected_ip[15]= "\0";
    int port;


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



    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;
    } else cout<<"Listening socket initialized...\nAccepting connections now..."<<endl;

    freeaddrinfo(result);

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

    // Accept a client socket
    ClientSocket = accept(ListenSocket, (struct sockaddr*)&client_info, NULL);
    if (ClientSocket == INVALID_SOCKET) {
        printf("accept failed with error: %d\n", WSAGetLastError());

        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    } else 

      // converting the address in readable form
      addr = inet_ntoa(client_info.sin_addr);
      printf("Client connected, IP address is: %s\n", addr );




    { 
    }




    closesocket(ListenSocket);




  for(;;)
    {

        cin.getline(typebuffer,50);
        strcpy(buffer,"SERVER: ");
        strcat(buffer,typebuffer);


        send( ClientSocket, buffer, 50, 0 );
        *buffer = '\0';



     }

    system("PAUSE");
    return EXIT_SUCCESS;
}

Answer 1

您正在向sockaddr_in提供accept()结构，但您没有告诉它结构有多大。您没有将sockaddr_in归零，accept()未填写，因此您在调用inet_ntoa()时会得到随机结果。记录此行为：

accept function

如果addr和/或addrlen等于NULL，则不会返回有关已接受套接字的远程地址的信息。

如果addrlen参数不为NULL，则addr参数不能为NULL：

int addrlen = sizeof(client_info); // <-- Add this
ClientSocket = accept(ListenSocket, (struct sockaddr*)&client_info, &addrlen);

在基于winsock 2的服务器程序上检索客户端IP地址时出现问题

1 个答案: