Socket编程：之TCP案例

转载请加上博文引用：http://i.cnblogs.com/EditPosts.aspx?postid=5733248&update=1

服务端：

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

 int sockfd;

 void do_service(int fd)
 {
     long t = time();
     char *s = ctime(&t);
     write(fd,s,strlen(s));
 }
 void out_client(struct sockaddr_in clientaddr)
 {
     char buffer[];
     inet_ntop(AF_INET,&clientaddr.sin_addr.s_addr,buffer,sizeof(clientaddr));
     unsigned short port = ntohs(clientaddr.sin_port);
     printf("client ip:%s (%d)\n",buffer,port);
 }

 int main(int argc,char *argv[])
 {
     if(argc < )
     {
         fprintf(stderr,"usage: %s port\n",argv[]);
         exit();
     }

     //创建套接字
     sockfd = socket(AF_INET,SOCK_STREAM,);
     if(sockfd < )
     {
         fprintf(stderr,"socket: %s\n",strerror(errno));
         exit();
     }

     //设置IP和端口
     struct sockaddr_in addr;
     memset(&addr,,sizeof(addr));
     addr.sin_family = AF_INET;
     addr.sin_port = htons(atoi(argv[]));
     addr.sin_addr.s_addr = INADDR_ANY; 

     //绑定IP和端口
     int len = sizeof(addr);
     if(bind(sockfd,(struct sockaddr*)&addr,len) < )
     {
         fprintf(stderr,"bind: %s\n",strerror(errno));
         exit();
     }

     //开始听
     if(listen(sockfd,) < )
     {
         fprintf(stderr,"listen: %s\n",strerror(errno));
         exit();
     }

     while()
     {
         struct sockaddr_in clientaddr;
         int c_len = sizeof(clientaddr);
         int fd = accept(sockfd,(struct sockaddr*)&clientaddr,&c_len);
         if(fd < )
         {
             fprintf(stderr,"accept: %s\n",strerror(errno));
             continue;
         }
         out_client(clientaddr);
         do_service(fd);
         close(fd);
     }
     return ;
 }

编译：

　　gcc -o server server.c

运行：

　　./server 6666

客户端：

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

 int sockfd;

 int main(int argc,char *argv[])
 {
     if(argc < )
     {
         fprintf(stderr,"usage: %s port\n",argv[]);
         exit();
     }

     sockfd = socket(AF_INET,SOCK_STREAM,);
     if(sockfd < )
     {
         fprintf(stderr,"socket:%s\n",strerror(errno));
         exit();
     }

     struct sockaddr_in sockaddr;
     memset(&sockaddr,,sizeof(sockaddr));
     sockaddr.sin_family = AF_INET;
     sockaddr.sin_port = htons(atoi(argv[]));
     inet_pton(AF_INET,argv[],&sockaddr.sin_addr.s_addr);
     socklen_t len = sizeof(sockaddr);

     if(connect(sockfd,(struct sockaddr*)&sockaddr,len) < )
     {
         fprintf(stderr,"connect: %s\n",strerror(errno));
         exit();
     }
     char buffer[];
     memset(buffer,,sizeof(buffer));
     ssize_t n;
     if((n = read(sockfd,buffer,)) < )
     {
         fprintf(stderr,"read: %s\n",strerror(errno));
         exit();
     }
     else
     {
         printf("%s\n",buffer);
     }

     return ;
 }

编译：

　　gcc -o client client.c

运行：

　　./client 192.168.0.30 6666