UDP编程服务端程序
#include <stdio.h>
#include <sys/types.h> /* See NOTES */
#include <sys/socket.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <unistd.h>
#include <fcntl.h>
#define SERVER_PORT 8888
#define BUFLEN 256
int setup_socket()
{
//1,创建socket
int sock_server = socket(AF_INET, SOCK_DGRAM, 0);
if(sock_server < 0)
{
perror("socket");
return -1;
}
//2,填充地址信息
struct sockaddr_in server_addr;
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(SERVER_PORT);
server_addr.sin_addr.s_addr = INADDR_ANY;
//设置可以复用地址
int on = 1;
if(setsockopt(sock_server, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1){
perror("setsockopt");
return -1;
}
//3,bind
if(bind(sock_server, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
{
return -1;
}
return sock_server;
}
int main()
{
char buf[BUFLEN] = {0};
int ret = 0, server_sock;
int fd =0;
int ret1=0;
struct sockaddr_in client_addr;
bzero(&client_addr, sizeof(client_addr));
socklen_t len = sizeof(client_addr);
server_sock = setup_socket();
if(server_sock < 0)
{
return -1;
}
while(1)
{
//4, 收数据
bzero(buf, sizeof(buf));
if((ret = recvfrom(server_sock, buf, BUFLEN-1, 0, (struct sockaddr*)&client_addr, &len)) < 0)
{
perror("recvfrom");
return -1;
}
printf("client ip:%s, port: %d\n", (char *)inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));
printf("recvfrom : %s\n", buf);
//发送数据给客户端
bzero(buf, sizeof(buf));
scanf("%s",buf);
ret = sendto(server_sock, buf,strlen(buf), 0, (const struct sockaddr * )&client_addr, len);
if(ret < 0)
{
perror("recvfrom");
return -1;
}
}
close(fd);
return ret;
}