[网络协议]基于TCP的回声服务器端/客户端

服务端

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>

#define BUF_SIZE 1024

void error_handling(char *message);

int main(int argc,char *argv[])
{
	int serv_sock,clnt_sock;
	char message[BUF_SIZE];
	int str_len;

	struct sockaddr_in serv_addr,clnt_addr;
	socklen_t clnt_addr_size;

	if(argc!=2)
	{
		printf("Usage : %s <port>\n" ,argv[0]);
		exit(1);
	}

	serv_sock=socket(PF_INET,SOCK_STREAM,0);

	memset(&serv_addr,0,sizeof(serv_addr));
	serv_addr.sin_family=AF_INET;
	serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
	serv_addr.sin_port=htons(atoi(argv[1]));

	if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1)
	{
		error_handling("bind() error");
	}

	if(listen(serv_sock,5)==-1)
	{
		error_handling("listen() error");
	}

	clnt_addr_size=sizeof(clnt_addr);

	for(int i=0;i<5;i++)
	{
		clnt_sock=accept(serv_sock,(struct sockaddr*)&clnt_addr,&clnt_addr_size);
		if(clnt_sock==-1)
			error_handling("accept() error");
		else
			printf("Connected client");
		while((str_len=read(clnt_sock,message,BUF_SIZE))!=0)
			write(clnt_sock,message,str_len);
		close(clnt_sock);
	}
	close(serv_sock);
	return 0;

}

//错误处理函数的实现
void error_handling(char *message)
{
	fputs(message,stderr);
	fputc('\n',stderr);
	exit(1);
}

客户端

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>

#define BUF_SIZE 1024
void error_handling(char *message);

int main(int argc,char *argv[])
{
	int sock;
	char message[BUF_SIZE];
	int str_len,recv_len,recv_cnt;
	struct sockaddr_in serv_addr;


	if(argc!=3)
	{
		printf("Usage : %s <IP> <port>\n" ,argv[0]);
		exit(1);
	}

	sock=socket(PF_INET,SOCK_STREAM,0);

	memset(&serv_addr,0,sizeof(serv_addr));
	serv_addr.sin_family=PF_INET;
	serv_addr.sin_addr.s_addr=inet_addr(argv[1]);
	serv_addr.sin_port=htons(atoi(argv[2]));

	if(connect(sock,(struct sockaddr *)&serv_addr,sizeof(serv_addr))==-1)
		error_handling("connect() error!");
	else
		puts("Connected......");
	while(1)
	{
		fputs("Input message(Q to quit): ",stdout);
		fgets(message,BUF_SIZE,stdin);
		if(!strcmp(message,"q\n")||!strcmp(message,"Q\n"))
			break;

		str_len=write(sock,message,strlen(message));
		recv_len=0;
		while(recv_len<str_len)
		{
			recv_cnt=read(sock,&message[recv_len],BUF_SIZE-1);
			if(recv_cnt==-1)
				error_handling("read() error!");
			recv_len+=recv_cnt;
		}
		message[str_len]=0;
		printf("Message from server: %s",message);

	}
	close(sock);
	return 0;
	
}

void error_handling(char *message)
{
	fputs(message,stderr);
	fputc('\n',stderr);
	exit(1);
}