Linux C语言下UDP实现指定端口收发数据实例

来源：互联网发布：100到999的水仙花数vb 编辑：程序博客网时间：2024/06/04 19:33

本文实现以下功能：

1.UDP sever指定往8888端口发送数据
2.UDP sever指定从9999端口接收数据
3.UDP client指定从9999端口接收数据
4.UDP client指定从8888端口接收数据
5.打开一终端执行./udp_server
6.打开另一终端执行./udp_client

7.udp_server每隔30秒向udp_client发送“TESTER_START_TEST\r\n”数据，udp_client收到后回复自己的IP信息给到udp_server，udp_server将收到的数据打印出来。

8.源代码：

a.服务器端

/*
* =====================================================================================
*
* Filename: udp_server.c
*
* Description:
*
* Version: 1.0
* Created: 04/06/2017 14:02:11 PM
* Revision: none
* Compiler: gcc udp_server.c -o udp_server
*
* Author: LI JUN LIANG
* Organization:
*
* =====================================================================================
*/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#define LOCAL_PORT 9999
#define REMOTE_PORT 8888
#define BUFFER_SIZE 1024
#define UDP_GO_TEST_FLAG "TESTER_START_TEST\r\n"

int main(int argc, char **argv)
{
char send_msg[BUFFER_SIZE] = {0};
char recv_msg[BUFFER_SIZE] = {0};//要接收的信息
int brdcFd;
struct tm *now;
time_t current_time = time((time_t *)NULL);
int send_msg_flag = 0;
int interval_sec = 30; //(send pre 30 sec)

if((brdcFd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)//建立套接字
{
printf("####L(%d) socket fail!\n", __LINE__);
exit(-1);
}

struct sockaddr_in local;
memset(&local, 0, sizeof(struct sockaddr_in));
local.sin_family = AF_INET;
local.sin_addr.s_addr = INADDR_ANY;
local.sin_port = htons(LOCAL_PORT);//UDP 广播包本地端口
socklen_t local_len = sizeof(struct sockaddr);

if(bind(brdcFd, (struct sockaddr *)&local, sizeof(local)))//绑定端口
{
printf("####L(%d) client bind port failed!\n", __LINE__);
close(brdcFd);//关闭socket
exit(-1);
}

int optval = 1;
setsockopt(brdcFd, SOL_SOCKET, SO_BROADCAST | SO_REUSEADDR, &optval, sizeof(int));

struct sockaddr_in remoteAddr;
memset(&remoteAddr, 0, sizeof(struct sockaddr_in));
remoteAddr.sin_family = AF_INET;
remoteAddr.sin_addr.s_addr = htonl(INADDR_BROADCAST);
remoteAddr.sin_port = htons(REMOTE_PORT);//UDP 广播包远端端口
int send_bytes, recv_bytes;

socklen_t addr_len = sizeof(struct sockaddr);

while(1)
{
if ((abs(time((time_t *)NULL) - current_time) >= interval_sec))
{
printf("####L(%d) going to send...\n", __LINE__);
current_time = time((time_t *)NULL);
if(!send_msg_flag)
send_msg_flag = 1;
}
else
{
if(send_msg_flag)
send_msg_flag = 0;
}

if(send_msg_flag)
{
memset(recv_msg, 0x0, sizeof(recv_msg));
memset(send_msg, 0x0, BUFFER_SIZE);
sprintf(send_msg, "%s", UDP_GO_TEST_FLAG);//要发送出去的广播信息

send_bytes = sendto(brdcFd, send_msg, strlen(send_msg), 0, (struct sockaddr *)&remoteAddr, addr_len);
if(send_bytes > 0) //发送完成
{
#if 1
recv_bytes = recvfrom(brdcFd, recv_msg, sizeof(recv_msg), MSG_DONTWAIT, (struct sockaddr *)&local, &local_len);
if(recv_bytes > 0)//收到内容
{
time(&current_time);
now = localtime(&current_time);

printf("####L(%d) [%4d-%02d-%02d %02d:%02d:%02d]UDP recv data:%s\n", __LINE__, now->tm_year + 1900, now->tm_mon + 1, now->tm_mday, now->tm_hour, now->tm_min, now->tm_sec, recv_msg);
}
#endif
}
else
{
printf("####L(%d) sendto fail, errno=%d \n", __LINE__, errno);
break;
}
}

usleep(500 * 1000);
}

close(brdcFd);

return 0;
}

b.客户端

/*
* =====================================================================================
*
* Filename: udp_client.c
*
* Description:
*
* Version: 1.0
* Created: 04/06/2017 14:29:26 PM
* Revision: none
* Compiler: gcc udp_client.c -o udp_client
*
* Author: LI JUN LIANG
* Organization:
*
* =====================================================================================
*/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <sys/ioctl.h>

#define LOCAL_PORT 8888
#define REMOTE_PORT 9999
#define BUFFER_SIZE 1024
#define UDP_GO_TEST_FLAG "TESTER_START_TEST\r\n"

int get_local_ip(char *ip, int len)
{
if((ip == NULL) || (len < 16))
{
printf("####L(%d) fail....\n", __LINE__);
return -1;
}
memset(ip, 0x0, len); //清空
int sock_get_ip;

struct sockaddr_in *sin;
struct ifreq ifr_ip;

if ((sock_get_ip = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
printf("####L(%d) socket create fail...get_local_ip!\n", __LINE__);
return -1;
}

memset(&ifr_ip, 0, sizeof(ifr_ip));
//获取网口的IP
strncpy(ifr_ip.ifr_name, "ens33", sizeof(ifr_ip.ifr_name) - 1);

if( ioctl( sock_get_ip, SIOCGIFADDR, &ifr_ip) < 0 )
{
printf("####L(%d) fail......\n", __LINE__);
close(sock_get_ip);
return -1;
}
sin = (struct sockaddr_in *)&ifr_ip.ifr_addr;
strcpy(ip, inet_ntoa(sin->sin_addr));

printf("####L(%d) local ip:%s \n", __LINE__, ip);
close( sock_get_ip);

return 0;
}

int main(int argc, char **argv)
{
char send_msg[BUFFER_SIZE] = {0};
char recv_msg[BUFFER_SIZE] = {0};
int brdcFd;
char localIp[16] = {0};
time_t current_time;
struct tm *now;

if((brdcFd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)//建立套接字
{
printf("####L(%d) socket fail!\n", __LINE__);
exit(-1);
}

struct sockaddr_in local;
memset(&local, 0, sizeof(struct sockaddr_in));
local.sin_family = AF_INET;
local.sin_addr.s_addr = INADDR_ANY;
local.sin_port = htons(LOCAL_PORT);//UDP 广播包本地端口
socklen_t local_len = sizeof(struct sockaddr);

if(bind(brdcFd, (struct sockaddr *)&local, sizeof(local)))//绑定端口
{
printf("####L(%d) client bind port failed!\n", __LINE__);
close(brdcFd);//关闭socket
exit(-1);
}

int optval = 1;
setsockopt(brdcFd, SOL_SOCKET, SO_BROADCAST | SO_REUSEADDR, &optval, sizeof(int));

struct sockaddr_in remoteAddr;
memset(&remoteAddr, 0, sizeof(struct sockaddr_in));
remoteAddr.sin_family = AF_INET;
remoteAddr.sin_addr.s_addr = htonl(INADDR_BROADCAST);
remoteAddr.sin_port = htons(REMOTE_PORT);//UDP 广播包远端端口
int send_bytes, recv_bytes;

socklen_t addr_len = sizeof(struct sockaddr);

get_local_ip(localIp, 16);

while(1)
{
memset(send_msg, 0x0, BUFFER_SIZE);
sprintf(send_msg, "%s\r", localIp);//要发送出去的广播信息
#if 1
memset(recv_msg, 0x0, sizeof(recv_msg));
recv_bytes = recvfrom(brdcFd, recv_msg, sizeof(recv_msg), MSG_DONTWAIT, (struct sockaddr *)&local, &local_len);
if(recv_bytes > 0)//收到内容
{
time(&current_time);
now = localtime(&current_time);

printf("####L(%d) [%4d-%02d-%02d %02d:%02d:%02d]UDP recv data:%s\n", __LINE__, now->tm_year + 1900, now->tm_mon + 1, now->tm_mday, now->tm_hour, now->tm_min, now->tm_sec, recv_msg);

if((0 == strncasecmp(recv_msg, UDP_GO_TEST_FLAG, strlen(UDP_GO_TEST_FLAG))))
{

if((send_bytes = sendto(brdcFd, send_msg, strlen(send_msg), 0,
(struct sockaddr *)&remoteAddr, addr_len)) == -1)
{
printf("####L(%d) sendto fail, errno=%d \n", __LINE__, errno);
break;
}

printf("####L(%d) [%4d-%02d-%02d %02d:%02d:%02d]alive send:ip[%s]\n", __LINE__, now->tm_year + 1900, now->tm_mon + 1, now->tm_mday, now->tm_hour, now->tm_min, now->tm_sec, localIp);
}
}
#endif
usleep(500 * 1000);
}
close(brdcFd);

return 0;
}

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