UDP-服务器端简单快捷模板

/* server.c */
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include "error.h"
#define MAXLINE 80
#define SERV_PORT 8000
int main(void)
{
 struct sockaddr_in servaddr, cliaddr;
 socklen_t cliaddr_len;
 int sockfd;
 char buf[MAXLINE];
 char str[INET_ADDRSTRLEN];
 int i, n;
 //socket         IPv4    SOCK_DGRAM
 sockfd = Socket(AF_INET, SOCK_DGRAM, 0);
 
 bzero(&servaddr, sizeof(servaddr));
 servaddr.sin_family = AF_INET;
 servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
     servaddr.sin_port = htons(SERV_PORT);
 //bind
 Bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
 printf("Accepting connections ... ");
 while (1)
 {
  cliaddr_len = sizeof(cliaddr);
  //recvfrom
  n = recvfrom(sockfd, buf, MAXLINE, 0, (struct sockaddr *)&cliaddr, &cliaddr_len);
  if (n == -1)
   perr_exit("recvfrom error");
  printf("received from %s at PORT %d ",
   inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)),ntohs(cliaddr.sin_port));
  //aaa--AAA
  for (i = 0; i < n; i++)
   buf[i] = toupper(buf[i]);
  n = sendto(sockfd, buf, n, 0, (struct sockaddr *)&cliaddr, sizeof(cliaddr));
  if (n == -1)
   perr_exit("sendto error");
 }
}