Question

我正在BeagleBone Black和我的电脑之间创建一个本地网络。两个设备都通过以太网连接。我的BleagleBone有IP地址=“192.168.1.15”，我的电脑有IP地址=“192.168.1.20”。我通过ssh连接连接到BeagleBone，以便将所有必要的文件传递给它。

另一方面，BleagleBone是此通信中的客户端，因为它会将数据字符串发送到muy PC（服务器）。

我使用以下代码：

server.cpp

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

using namespace std;

#define PORT 20001
#define SERVER_BUFFER_SIZE  1024

void error(const char *msg)
{
    perror(msg);
    exit(1);
}

int main(int argc, char *argv[])
{
     int sockfd, newsockfd, portno;
     socklen_t clilen;
     char buffer[256];
     struct sockaddr_in serv_addr, cli_addr;
     int n;
     if (argc < 2) {
         fprintf(stderr,"ERROR, no port provided\n");
         exit(1);
     }
     // create a socket
     // socket(int domain, int type, int protocol)
     printf("\nHola1");
     sockfd =  socket(AF_INET, SOCK_STREAM, 0);
     printf("\nHola2");
     if (sockfd < 0){
        error("ERROR opening socket");
     }
     printf("\nHola3");

     // clear address structure
     bzero((char *) &serv_addr, sizeof(serv_addr));

     portno = atoi(argv[1]);

     /* setup the host_addr structure for use in bind call */
     // server byte order
     serv_addr.sin_family = AF_INET;

     // automatically be filled with current host's IP address
     serv_addr.sin_addr.s_addr = INADDR_ANY;

     // convert short integer value for port must be converted into network byte order
     serv_addr.sin_port = htons(portno);

     // bind(int fd, struct sockaddr *local_addr, socklen_t addr_length)
     // bind() passes file descriptor, the address structure,
     // and the length of the address structure
     // This bind() call will bind  the socket to the current IP address on port, portno
     if (bind(sockfd, (struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)
              error("ERROR on binding");

     // This listen() call tells the socket to listen to the incoming connections.
     // The listen() function places all incoming connection into a backlog queue
     // until accept() call accepts the connection.
     // Here, we set the maximum size for the backlog queue to 5.
     listen(sockfd,5);

     // The accept() call actually accepts an incoming connection
     clilen = sizeof(cli_addr);

     // This accept() function will write the connecting client's address info
     // into the the address structure and the size of that structure is clilen.
     // The accept() returns a new socket file descriptor for the accepted connection.
     // So, the original socket file descriptor can continue to be used
     // for accepting new connections while the new socker file descriptor is used for
     // communicating with the connected client.
     newsockfd = accept(sockfd,
                 (struct sockaddr *) &cli_addr, &clilen);
     if (newsockfd < 0)
          error("ERROR on accept");

     printf("server: got connection from %s port %d\n",inet_ntoa(cli_addr.sin_addr), ntohs(cli_addr.sin_port));


     // This send() function sends the 13 bytes of the string to the new socket
     send(newsockfd, "Hello, world!\n", 13, 0);

     bzero(buffer,256);

     n = read(newsockfd,buffer,255);
     if (n < 0) error("ERROR reading from socket");
     printf("Here is the message: %s\n",buffer);

     close(newsockfd);
     close(sockfd);
     return 0;
}

client.cpp

int main(int argc, char *argv[])
{
    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;

    char buffer[256];
    if (argc < 3) {
       fprintf(stderr,"usage %s hostname port\n", argv[0]);
       exit(0);
    }
    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0)
        error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr,(char *)&serv_addr.sin_addr.s_addr,server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
        error("ERROR connecting");
    printf("Please enter the message: ");
    bzero(buffer,256);
    fgets(buffer,255,stdin);
    n = write(sockfd, buffer, strlen(buffer));
    if (n < 0)
         error("ERROR writing to socket");
    bzero(buffer,256);
    n = read(sockfd, buffer, 255);
    if (n < 0)
         error("ERROR reading from socket");
    printf("%s\n", buffer);
    close(sockfd);
    return 0;
}

首先，我通过以下命令在./Server 20001上运行服务器可执行文件然后我通过./Client 192.168.1.20 20001

在BleagleBone中运行客户端

我在BeagleBone上获得的是： ERROR连接：拒绝连接

我不明白为什么它不起作用。

注意：当我指定一个端口时，它不会绑定。只是停止在那里工作，它不会给出错误。

BeagleBone Black和PC之间的TCP / IP通信

0 个答案: