Linux C 网络编程——4. 容易TCP Socket程序

Linux C 网络编程——4. 简单TCP Socket程序

根据图中的流程，实现一个最简单的TCP程序。

1. 客户端

功能：发送一个字符串给服务器

/*
 ============================================================================
 Name        : SimpleSockTCPClient.c
 Author      : wistone
 Version     :
 Copyright   : 2012 - 2015
 Description : Simple Socket Client
 ============================================================================
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>


int main( int argc, char** argv )
{
	struct sockaddr_in server_addr_in;
	char buf[100];

	int cfd;
	int port = 8001;

	char *str = "test string";

	if( argc > 1 )
	{
		str = argv[1];
	}

	cfd = socket( AF_INET, SOCK_STREAM, 0 );

	bzero( &server_addr_in, sizeof(server_addr_in) );

	server_addr_in.sin_family = AF_INET;
	server_addr_in.sin_port = htons(port);
	inet_pton( AF_INET, "127.0.0.1", &server_addr_in.sin_addr );

	connect( cfd, (struct sockaddr *)&server_addr_in, sizeof(server_addr_in) );

	send( cfd, str, strlen(str)+1, 0 );
	//write( cfd, str, strlen(str)+1 );
	//read(cfd, buf, 100);
	recv( cfd, buf, 100, 0 );
	
	close(cfd);

	printf("Recive from server : %s \n", buf);

	return 0;
}

2. 服务器

把收到的字符串转成大写，然后发回去

/*
 ============================================================================
 Name        : SimpleSockTCPServer.c
 Author      : wistone
 Version     :
 Copyright   : 2012 - 2015
 Description : Simple Socket Server
 ============================================================================
 */
#include <stdio.h>
#include <stdlib.h>

#include <arpa/inet.h>
#include <sys/socket.h>

int main( int argc , char ** argv )
{
	struct sockaddr_in saddr, caddr;

	char buf[100] ;
	char str[100] ;

	int listenfd, connfd;
	int addr_len;

	listenfd = socket( AF_INET, SOCK_STREAM, 0 );

	memset ( &saddr, 0, sizeof(saddr) );
	memset( buf, 0, 100 );
	memset( buf, 0, 100 );
	saddr.sin_family = AF_INET;
	saddr.sin_port = htons( 8001 );
	saddr.sin_addr.s_addr = htonl( INADDR_ANY ); //any address

	bind( listenfd, (struct sockaddr *)&saddr, 16 );

	listen( listenfd, 20 );

	printf( "Accepting connections ... \n" );

	int i, n;
	while(1)
	{
		addr_len = sizeof( caddr );
		connfd = accept( listenfd, (struct sockaddr*)&caddr, &addr_len );

		//n = read( listenfd, buf, 100 );
		n = recv( listenfd, buf, 100, 0  );
		
		printf("Recive from %s : %d \n",  inet_ntop( AF_INET, &caddr.sin_addr, str, sizeof(str) ), ntohs(caddr.sin_port) );

		for(i=0; i<n; i++)
		{
			buf[i] = toupper( buf[i] );
		}

		//write( connfd, buf, n+1 );
		send( connfd, buf, n+1, 0 );
		
		printf("Send : %s \n", buf);
		close( connfd );
	}

	return 0;
}

3. 参考

[1] Linux C编程一站式学习

[2] Linux 网络编程