网络编程——UDP服务器

#include <stdio.h>
#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>

#define  PORT   9995

void handl_client(char *buf)
{
	int i;
	for (i = 0; i < strlen(buf)-1; i++)
	{
		buf[i] += 'A' - 'a';
	}
}


// 监听套接字
int init()
{
	int conm_socket = socket(AF_INET, SOCK_DGRAM, 0);
	if(-1 == conm_socket)
	{
		perror("创建套接字失败");
		return -1;
	}
	
	struct sockaddr_in addr;
	memset(&addr, 0, sizeof(struct sockaddr_in));
	addr.sin_family      = AF_INET;             /* Internet地址族 */
	addr.sin_port        = htons(PORT);         /* 端口号 */
	addr.sin_addr.s_addr = htonl(INADDR_ANY);   /* IP地址, 绑定本地的所有ip地址*/

	int ret = bind(conm_socket, (const struct sockaddr *)&addr, sizeof(addr));
	if(-1 == ret)
	{
		perror("绑定失败");
		return -1;
	}
	
	return conm_socket;
}

int main(int argc, char **argv)
{
	int conm_socket = init();
	if (-1 == conm_socket)
		return;
	
	char buf[1024];
	while (1)
	{
		struct sockaddr_in client_addr;
		socklen_t  len = sizeof(client_addr);
		ssize_t ret = recvfrom(conm_socket, buf, 1023, 0, (struct sockaddr *)&client_addr, &len);// 收
		buf[ret] = '\0';
		handl_client(buf);     // 处理
		
		sendto(conm_socket, buf, ret, 0, (struct sockaddr *)&client_addr,  len);// 回
	}
	
	
	return 0;
}