我刚开始接触linux下的socket编程，边抄边理解udp socket编程，我的疑问是server不指定IP地址，client的目标IP地址是127.0.0.1，这样就可以通信吗？在同一主机下是不是不能测试？如果server默认绑定本机的IP 地址，那么开启server后，在浏览器中输入127.0.0.1:(相应端口) 也可以得到数据？我的程序如下，没有跑起来，其实我觉得我不会测试，不知道本质所以会有细节漏掉。（使用的系统是ubuntu 11.10 ，编译器GCC ，分别在同一主机下的两个终端中运行生成的.out文件。）提前感谢大家的回答，不管多少，您的回答让一个初学者非常暖心～～
服务器程序
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#include<stdio.h>#include<netinet/in.h>#include<arpa/inet.h>#include<unistd.h>#include<sys/types.h>#include<sys/socket.h>#define lport 4567int main()
{ int mysock,len;
struct sockaddr_in addr;
int i=0;
char msg[256];
int addr_len;
if((mysock=socket(AF_INET,SOCK_DGRAM,0))<0)
{
perror("error");
exit(1);
}
else
{
printf("socket created.\n");
printf("socket ID: %d\n",mysock);
}
addr_len=sizeof(struct sockaddr_in);
bzero(&addr,sizeof(addr));
addr.sin_family=AF_INET;
addr.sin_port=htons(lport);
addr.sin_addr.s_addr=htonl(INADDR_ANY);
if(bind(mysock,&addr,sizeof(addr))<0)
{
perror("connect");
exit(1);
}
else
{
printf("bind ok.\n");
printf("local port: %d\n",lport);
}
while(1)
{
bzero(msg,sizeof(msg));
len=recvfrom (mysock,msg,sizeof(msg),0,&addr,&addr_len);
printf("%d: ",i);
i++;
printf("message form: %s\n",inet_ntoa(addr.sin_addr));
printf("message: %s\n\n",msg);
sendto(mysock,msg,len,0,&addr,addr_len);
}
return 0;
} |
客户机程序：
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#include<stdio.h>#include<netinet/in.h>#include<arpa/inet.h>#include<unistd.h>#include<fcntl.h>#include<sys/stat.h>#include<sys/types.h>#include<sys/socket.h>#define rport 4567#define rip "127.0.0.1"int main()
{ int s,len;
struct sockaddr_in addr;
int addr_len;
char msg[256];
int i=0;
if((s=socket(AF_INET,SOCK_DGRAM,0))<0)
{
perror("error");
exit(1);
}
else
{
printf("socket created.\n");
printf("socket id: %d\n",s);
printf("romote ip: %s\n",rip);
printf("remote port: %d\n",rport);
}
len=sizeof(struct sockaddr_in);
bzero(&addr,sizeof(addr));
addr.sin_family=AF_INET;
addr.sin_port=htons(rport);
addr.sin_addr.s_addr=inet_addr(rip);
while(1)
{
bzero(msg,sizeof(msg));
len=read(STDIN_FILENO,msg,sizeof(msg));
sendto(s,msg,len,0,&addr,addr_len);
printf("\nInput message: %s\n",msg);
len=recvfrom(s,msg,sizeof(msg),0,&addr,&addr_len);
printf("%d :",i);
i++;
printf("received message: %s \n",msg);
}
return 0;
} |