receive.c

中科院徐志伟老师一书《操作系统 原理·技术与编程》的源代码和习题接

#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
 
char * host_name = "127.0.0.1"; // local host
int port = 9889;

void main() {
  int cliaddr_len;
  char recvbuf[256],sendbuf[256];
  int sockfd;
  struct sockaddr_in servaddr,cliaddr;
  struct hostent *shost_name;

   if ((shost_name = gethostbyname(host_name)) == 0) {
    perror("Error resolving local host\n");
    exit(1);
  }

  bzero(&servaddr, sizeof(servaddr));
  servaddr.sin_family = AF_INET;
  servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
  servaddr.sin_port = htons(port);
  if ((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) == -1) {
    perror("Error opening socket\n");
    exit(1);
  }

  if (bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
    perror("call to bind");
  }

  while (1) {
    cliaddr_len = sizeof(cliaddr);
    if (recvfrom(sockfd, recvbuf, 256, 0,(struct sockaddr *)&cliaddr, &cliaddr_len) == -1) {
      perror("Error in receiving response from server\n");
    }
    sprintf(sendbuf, "I got it.\n");
    sendto(sockfd,sendbuf,256,0,(struct sockaddr*)&cliaddr,cliaddr_len);
    printf("\nResponse from server:\n\n%s\n", recvbuf);
    if (strncmp(recvbuf, "stop", 4) == 0) break;
  }
  close(sockfd);
}