Question

最近我一直在努力用C套接字做很多事情，因为它是我将来需要的一种语言。但是我遇到了这个问题，我无法解决。我做了客户端和服务器 - 不幸的是，这两个二进制文件拒绝相互连接。我的意思是，当我在同一台机器上运行服务器二进制文件和客户端二进制文件时，我没有得到任何错误，但也没有任何连接。有任何想法吗？这是代码！

（Ubuntu，使用gcc编译的C代码，服务器和客户端代码都在2个不同终端的同一台机器上运行。）

Server.c：

    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h> 
    #include <string.h>
    #include <sys/socket.h>
    #include <arpa/inet.h> //inet_aton(), inet_ntoa() etc
    #include <sys/types.h>
    #include <netinet/in.h>

    #define PORT 8000
    #define ERROR perror("Something went wrong! => ");
    #define BUFFERSIZE 256
    int main()
    {
        int sockfd, client_socketfd; 
        int bytes_sent; 
        socklen_t sin_size;
        struct sockaddr_in server_addr;
        struct sockaddr_in connectedClient_addr;
        char message[BUFFERSIZE] = "Welcome to the server!";

        if((sockfd = socket(PF_INET, SOCK_STREAM ,0)) == -1) {
            ERROR;
            exit(-1);
        }

        server_addr.sin_family = AF_INET;
        server_addr.sin_port   = htons(PORT);
        server_addr.sin_addr.s_addr = INADDR_ANY; //Subject to change


        if((bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr))) == -1) {
            ERROR;
            exit(-2);
        }


        if((listen(sockfd, 5)) == -1) {
            ERROR;
            exit(-3);
        }   

        int addrlen = sizeof(connectedClient_addr);
        if((client_socketfd = accept(sockfd, (struct sockaddr *)&connectedClient_addr, (socklen_t*)&addrlen)) == -1){
            ERROR;
            exit(-4);
        }   

        printf("Got a connection from: %s at port: %d" , inet_ntoa(connectedClient_addr.sin_addr), PORT);

        if((send(sockfd, &message, BUFFERSIZE, 0)) == -1) {
             ERROR;
             exit(-5);
        }

         close(sockfd);
         close(client_socketfd);

        return 0;
    }

-

Client.c：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>


#define PORT 8000
#define ERROR perror("Something went wrong! =>");
#define BUFFERSIZE 256
int main()
{
    int sockfd;
    struct sockaddr_in client_addr;
    char message[BUFFERSIZE] = "Successfully connected!";
    int bytes_received, bytes_sent;
    char buffer[BUFFERSIZE];


    if((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
        ERROR;
        exit(-1);
    }


    client_addr.sin_family = AF_INET;
    client_addr.sin_port   = htons(PORT);
    client_addr.sin_addr.s_addr = INADDR_ANY;


    if((connect(sockfd, (struct sockaddr*)&client_addr, sizeof(client_addr))) == -1) {
        ERROR;
        exit(-2);
    }

    if((bytes_received = recv(sockfd, &buffer, BUFFERSIZE, 0)) == -1) {
        ERROR;
        exit(-3);
    }

    printf("Received %d bytes:\n" , bytes_received);
    printf("%s", buffer);

    close(sockfd);

    return 0;
}

Answer 1

<强>解答：问题是我在 server.c 中的send()函数内部而不是客户端套接字中提供了服务器套接字。因此代码工作没有任何错误，但行为是不正确的。归功于RemyLebeau in the comments，他指出了这一点并为我节省了无数个小时的挣扎。

C套接字（Linux）将无法连接

1 个答案: