C 使用UDP协议从服务器向多个客户端广播消息
我这里有两个UDP聊天的代码,其中有一个广播机制,服务器可以同时向所有客户端广播消息 服务器代码C 使用UDP协议从服务器向多个客户端广播消息,c,linux,network-programming,udp,broadcasting,C,Linux,Network Programming,Udp,Broadcasting,我这里有两个UDP聊天的代码,其中有一个广播机制,服务器可以同时向所有客户端广播消息 服务器代码 #include<stdio.h> #include<string.h> #include<sys/stat.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> #include<arpa/inet.h> int mai
#include<stdio.h>
#include<string.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
int main(int argc, char *argv[] )
{
struct sockaddr_in client,server;
int s,n;
char b1[100],b2[100];
s=socket(AF_INET,SOCK_DGRAM,0);
server.sin_family=AF_INET;
server.sin_port=htons(2000);
server.sin_addr.s_addr=inet_addr("127.0.0.1");
bind(s,(struct sockaddr *)&server,sizeof(server));
printf("\nServer ready,waiting for client....\n");
n=sizeof(client);
int sock; /* Socket */
struct sockaddr_in broadcastAddr; /* Broadcast address */
char *broadcastIP; /* IP broadcast address */
unsigned short broadcastPort; /* Server port */
char *sendString; /* String to broadcast */
int broadcastPermission; /* Socket opt to set permission to broadcast */
unsigned int sendStringLen; /* Length of string to broadcast */
if (argc < 4) /* Test for correct number of parameters */
{
fprintf(stderr,"Usage: %s <IP Address> <Port> <Send String>\n", argv[0]);
exit(1);
}
broadcastIP = argv[1]; /* First arg: broadcast IP address */
broadcastPort = atoi(argv[2]); /* Second arg: broadcast port */
sendString = argv[3]; /* Third arg: string to broadcast */
/* Create socket for sending/receiving datagrams */
sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
broadcastPermission = 1;
while(1)
{
recvfrom(s,b1,sizeof(b1),0,(struct sockaddr *) &client,&n);
if(!(strcmp(b1,"end")))
break;
printf("\nClient:%s",b1);
printf("\nServer:");
gets(b2);
sendto(s,b2,sizeof(b2),0,(struct sockaddr *) &client,n);
broadcastPermission = 1;
setsockopt(sock, SOL_SOCKET, SO_BROADCAST, (void *) &broadcastPermission,sizeof(broadcastPermission));
/* Construct local address structure */
//memset(&broadcastAddr, 0, sizeof(broadcastAddr)); /* Zero out structure */
broadcastAddr.sin_family = AF_INET; /* Internet address family */
broadcastAddr.sin_addr.s_addr = inet_addr(broadcastIP);/* Broadcast IP address */
broadcastAddr.sin_port = htons(broadcastPort); /* Broadcast port */
sendStringLen = strlen(sendString);
for (;;) /* Run forever */
{
/* Broadcast sendString in datagram to clients every 3 seconds*/
sendto(sock, sendString, sendStringLen, 0, (struct sockaddr *) &broadcastAddr, sizeof(broadcastAddr));
// DieWithError("sendto() sent a different number of bytes than expected");
//sleep(3); /* Avoids flooding the network */
}
}
}
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int main(int argc,char*argv[])
{
客户端、服务器中的结构sockaddr_;
int s,n;
字符b1[100],b2[100];
s=插座(AF INET,SOCK DGRAM,0);
server.sinu family=AF\u INET;
server.sinu port=htons(2000);
server.sin_addr.s_addr=inet_addr(“127.0.0.1”);
绑定(结构sockaddr*)和服务器,大小为(服务器));
printf(“\n服务器就绪,正在等待客户端…”\n”);
n=sizeof(客户);
int sock;/*套接字*/
broadcastAddr;/*广播地址中的结构sockaddr_*/
字符*广播IP;/*IP广播地址*/
未签名的短广播端口;/*服务器端口*/
char*sendString;/*要广播的字符串*/
int broadcastPermission;/*套接字选择设置广播权限*/
unsigned int sendStringLen;/*要广播的字符串长度*/
如果(argc<4)/*测试参数数量是否正确*/
{
fprintf(stderr,“用法:%s\n”,argv[0]);
出口(1);
}
broadcastIP=argv[1];/*第一个arg:广播IP地址*/
broadcastPort=atoi(argv[2]);/*第二个arg:广播端口*/
sendString=argv[3];/*第三个arg:要广播的字符串*/
/*创建用于发送/接收数据报的套接字*/
sock=套接字(PF_INET、sock_DGRAM、IPPROTO_UDP);
广播权限=1;
而(1)
{
recvfrom(s,b1,sizeof(b1),0,(struct sockaddr*)和client,&n);
如果(!(strcmp(b1,“结束”))
打破
printf(“\n客户端:%s”,b1);
printf(“\n服务器:”);
gets(b2);
sendto(s,b2,sizeof(b2),0,(struct sockaddr*)和client,n);
广播权限=1;
setsockopt(sock、solu套接字、SO_广播(void*)和broadcastPermission、sizeof(broadcastPermission));
/*构造本地地址结构*/
//memset(&broadcastAddr,0,sizeof(broadcastAddr));/*零输出结构*/
broadcastAddr.sin_family=AF_INET;/*互联网地址系列*/
broadcastAddr.sin_addr.s_addr=inet_addr(广播IP);/*广播IP地址*/
broadcastAddr.sin_port=htons(broadcastPort);/*广播端口*/
sendStringLen=strlen(sendString);
为了(;)/*永远奔跑*/
{
/*每3秒向客户端广播数据报中的sendString*/
sendto(sock,sendString,sendStringLen,0,(struct sockaddr*)和broadcastAddr,sizeof(broadcastAddr));
//DIEWERROR(“sendto()发送的字节数与预期的不同”);
//睡眠(3);/*避免网络泛滥*/
}
}
}
客户端代码
#include<stdio.h>
#include<string.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#define MAXRECVSTRING 255
int main(int argc , char argv[])
{
struct sockaddr_in client,server;
int s,n;
char b1[100],b2[100];
s=socket(AF_INET,SOCK_DGRAM,0);
server.sin_family=AF_INET;
server.sin_port=htons(2000);
server.sin_addr.s_addr=inet_addr("127.0.0.1");
printf("\nClient ready....\n");
n=sizeof(server);
int sock; /* Socket */
struct sockaddr_in broadcastAddr; /* Broadcast Address */
unsigned short broadcastPort; /* Port */
char recvString[MAXRECVSTRING+1]; /* Buffer for received string */
int recvStringLen; /* Length of received string */
if (argc != 2) /* Test for correct number of arguments */
{
fprintf(stderr,"Usage: %s <Broadcast Port>\n", argv[0]);
exit(1);
}
printf("\nClient ready…11111.\n");
broadcastPort = htons(argv[1]); /* First arg: broadcast port */
printf("\nClient ready….1\n");
/* Create a best-effort datagram socket using UDP */
if(sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)<0)
printf("no sock created");
printf("\nClient ready….2\n");
while(1)
{
printf("\nClient:");
gets(b2);
sendto(s,b2,sizeof(b2),0,(struct sockaddr *) &server,n);
if(strcmp(b2,"end")==0)
break;
recvfrom(s,b1,sizeof(b1),0,NULL,NULL);
printf("\nServer:%s",b1);
broadcastAddr.sin_family = AF_INET; /* Internet address family */
broadcastAddr.sin_addr.s_addr = htonl(INADDR_ANY); /* Any incoming interface */
broadcastAddr.sin_port = htons(broadcastPort); /* Broadcast port */
/* Bind to the broadcast port */
bind(sock, (struct sockaddr *) &broadcastAddr, sizeof(broadcastAddr));
/* Receive a single datagram from the server */
recvStringLen = recvfrom(sock, recvString, MAXRECVSTRING, 0, NULL, 0);
recvString[recvStringLen] = '\0';
printf("Received: %s\n", recvString); /* Print the received string */
}
close(sock);
}
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#定义MAXRECVSTRING 255
int main(int argc,char argv[]
{
客户端、服务器中的结构sockaddr_;
int s,n;
字符b1[100],b2[100];
s=插座(AF INET,SOCK DGRAM,0);
server.sinu family=AF\u INET;
server.sinu port=htons(2000);
server.sin_addr.s_addr=inet_addr(“127.0.0.1”);
printf(“\n客户端就绪…”\n”);
n=sizeof(服务器);
int sock;/*套接字*/
broadcastAddr;/*广播地址中的结构sockaddr_*/
未签名的短广播端口;/*端口*/
char recvString[MAXRECVSTRING+1];/*接收字符串的缓冲区*/
int recvStringLen;/*接收字符串的长度*/
如果(argc!=2)/*测试参数数量是否正确*/
{
fprintf(stderr,“用法:%s\n”,argv[0]);
出口(1);
}
printf(“\n客户端就绪…11111。\n”);
broadcastPort=htons(argv[1]);/*第一个arg:广播端口*/
printf(“\n客户端就绪….1\n”);
/*使用UDP创建尽力数据报套接字*/
如果(sock=socket(PF_INET,sock_DGRAM,IPPROTO_UDP)开始:
server.sin_port=2000;
您忘了下此网络订单。某些平台(如Windows)将不接收广播,除非套接字绑定到INADR\u ANY,即0.0.0.0。在您的服务器代码中:
套接字没有绑定到任何IP地址。虽然它广播消息并由客户端接收,但反之亦然。
因此,将服务器端和客户端套接字绑定到2个不同的IP地址。
当服务器广播消息时,在sendto功能中使用适当的广播地址(请参阅服务器客户端IP的子网)。我将端口更改为网络顺序,但客户端和服务器仍然没有相互接收消息!!服务器和客户端的网络配置(IP地址和网络掩码)是什么?