tcpclient.c

有关linux的tcp和udp通讯的服务器端和客服端的源程序

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


#define BUFSIZE			8192
#define DEFAULT_PORT	5320

enum {CMD_NAME,DST_IP,DST_PORT};

int main(int argc, char *argv[])
{
	unsigned long dst_ip;
	int port;
	int s,zero;
	char cmd[BUFSIZE];
	char buf[BUFSIZE];
	
	struct sockaddr_in server;
	struct sockaddr_in client;
	struct timeavl tv;
	fd_set readfd;
	
	if(argc != 2 && argc!=3){
		fprintf(stderr," Usag: %s hostname [port]\n",argv[0]);
		exit(EXIT_FAILURE);
	}
	if((dst_ip=inet_addr(argv[DST_IP]))==INADDR_NONE){
		struct hostent* he;
		if((he=gethostbyname(argv[DST_IP]))==NULL){
			fprintf(stderr,"gethostbyname error\n");
			exit(EXIT_FAILURE);

		}
		memcpy((char*)&dst_ip,(char*)he->h_addr,he->h_length);
	}

	if(argc==3){
		if((port=(atoi(argv[DST_PORT]))=0){
			struct servent *se;
			if((se=getservbyname(argv[DST_PORT],"upd"))!=NULL)
				port=(int)ntohs((u_short)se->port);
			else{
				fprintf(stderr,"getservbynmame error\n");
				exit(EXIT_FAILURE);
			}
		}
	}
	else port=DEFAULT_PORT;

	
/*Step 1 */
	if((s=socket(AF_INET,SOCK_STREAM,0)<0){
		perror("socket");
		exit(EXIT_FAILURE);
	}
/*step	2 */
	memset((char*)&server,0,sizeof(server));
	server.sin_family=AF_INET;
	server.sin_addr.s_addr=dst_ip;
	server.sin_port=htons(port);

	if(connect(s,(struct sockaddr*)&server,sizeof(server)<0)
		perror("connect");
		exit(EXIT_FAILURE);
	}
	while(1){
		tv.tv_sec=600;
		tv.tv_usec=0;
		FD_ZERO(&readfd);
		FD_SET(0,&readfd);
		FD_SET(s,&readfd);
		if((select(s+1,&readfd,NULL,NULL,&tv))<=0){
			perror("timeout");
			break;
		}
		if(FD_ISSET(0,&readfd)){
			if((n=read(0,buf,BUFSIZE-1))<=0)
				break;
			buf[n]='\0';
			sscanf(buf,"%s",cmd);
			if(strcmp(cmd,"quit")==0) break;
			if(sendto(s,buf,n,0)<0)
				break;
		}
		if(FD_ISSET(s,&readfd)){
			if((n=recv(s0,buf,BUFSIZE-1))<=0){
				perror("timeout");
				exit(-1);
			}
			buf[n]='\0';
			printf("%s",buf);
			fflush(stdout);
		}
	}
	strcpy(buf,"quit");
	send(s,buf,n,0);

	close(s);
	return 0;
}