UDP广播通信

服务器端代码：

serverUDP.c

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

#define PORT 6023

struct FightingStatus{
	int targetNo;
	int missileNo;
};

int main()  
{  
    setvbuf(stdout, NULL, _IONBF, 0);   
    fflush(stdout);   
 
    int sock = -1;  
    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)   
    {     
        printf("socket error\n");   
        return -1;  
    }     
      
    const int opt = 1;  
    //设置该套接字为广播类型，  
    int nb = 0;  
    nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));  
    if(nb == -1)  
    {  
        printf("set socket error...\n");  
        return -1;  
    }  
 
    struct sockaddr_in addrto;  
    bzero(&addrto, sizeof(struct sockaddr_in));  
    addrto.sin_family=AF_INET;  
    addrto.sin_addr.s_addr=htonl(INADDR_BROADCAST);  
    addrto.sin_port=htons(PORT);  
    int nlen=sizeof(addrto);  
    struct FightingStatus status;
    while(1)  
    {  
        sleep(1);  
        //从广播地址发送消息  
        char smsg[] = {"abcdef"};
	status.targetNo = 1;
	status.missileNo = 2;
        int ret=sendto(sock, (char*)&status, sizeof(struct FightingStatus), 0, (struct sockaddr*)&addrto, nlen);  
        if(ret<0)  
        {  
            printf("send error....\n");  
        }  
        else  
        {         
            printf("ok \n");    
        }  
    }  
 
    return 0;  
}  

客户端代码：

clientUDP.c

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
 
#define PORT 6023

struct FightingStatus{
	int targetNo;
	int missileNo;
   	int flag;
};

int main()  
{  
    setvbuf(stdout, NULL, _IONBF, 0);   
    fflush(stdout);   
 
    // 绑定地址  
    struct sockaddr_in addrto;  
    bzero(&addrto, sizeof(struct sockaddr_in));  
    addrto.sin_family = AF_INET;  
    addrto.sin_addr.s_addr = htonl(INADDR_ANY);  
    addrto.sin_port = htons(PORT);  
      
    // 广播地址  
    struct sockaddr_in from;  
    bzero(&from, sizeof(struct sockaddr_in));  
    from.sin_family = AF_INET;  
    from.sin_addr.s_addr = htonl(INADDR_ANY);  
    from.sin_port = htons(PORT);  
      
    int sock = -1;  
    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)   
    {     
        printf("socket error\n");   
        return -1;  
    }     
 
    const int opt = 1;  
    //设置该套接字为广播类型，  
    int nb = 0;  
    nb = setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (char *)&opt, sizeof(opt));  
    if(nb == -1)  
    {  
        printf("set socket error...\n");  
        return -1;  
    }  
 
    if(bind(sock,(struct sockaddr *)&(addrto), sizeof(struct sockaddr_in)) == -1)   
    {     
        printf("bind error...\n");  
        return -1;  
    }  
 
    int len = sizeof(struct sockaddr_in);  
    char smsg[100] = {0};  
    struct FightingStatus status;
    while(1)  
    {  
        //从广播地址接受消息  
        int ret=recvfrom(sock, (char*)&status, sizeof(struct FightingStatus), 0, (struct sockaddr*)&from,(socklen_t*)&len);  
        if(ret<=0)  
        {  
            printf("read error....\n");  
        }  
        else  
        { 
		printf("read successdul....\n");  
            printf("%d***%d***%d\n", status.targetNo, status.missileNo,status.flag);     
        }  
 
        sleep(1);  
    }  
 
    return 0;  
}