mdesproxy.c

如果是通过公司内部的HTTP PROXY上网而又被限制访问很多站点的话

/*
* desproxy.c: Main program file for desproxy
*
* Copyright (C) 2003 Miguelanxo Otero Salgueiro
*
* This program is free software; you can redistribute it and/or modify
* it under the tems of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/

#include "mdesproxy.h"
#define PROGRAM_NAME "desproxy"
#define PROGRAM_VERSION VERSION
#define CONTLEN "Content-Length: "
int alivetime;
int mintime;
int request_socket;
int connection_status[MAX_CONNECTIONS];
char  *remote_port;
void process_connection_request(struct pb *,int );
char hostname[256][50];
int first;
struct pb pb;
void sig_child(int );
int read_request(struct pb *prob)
{
	prob->len=read(prob->sockcli,prob->buffer,sizeof(prob->buffer));
	if(prob->len<=0){
		printf("readd from client err\n");
		return -1;
	}
	return 0;
}
int client_to_proxy (struct pb *prob)
{
	int count;
	if ((count = write (prob->sockproxy,prob->buffer, prob->len)) == -1)
	{
		perror ("write");
		return -1;
	}
	return 0;
}

int proxy_to_client (struct pb *prob)
{
	int count;

	if ((count = read (prob->sockproxy,prob->buffer, sizeof (prob->buffer))) == -1)
	{
		perror ("read");
		return -1;
	}
	else
	{
		if ((count = write (prob->sockcli, prob->buffer, count)) == -1)
		{
			perror ("write");
			return -1;
		}
	}
	return 0;
}

void
parse_command_line (int argc, char **argv)
{
	debug_printf (">parse_command_line(COMMAND_LINE)\n");
	if (argc != 5)
	{
		printf (gettext
		("Usage: desproxy remote_port proxy_host"
		" proxy_port local_port\n\n"));
		exit (1);
	}
	remote_port = argv[1];
	proxy_host = argv[2];
	proxy_port = argv[3];
	local_port = argv[4];
	debug_printf ("parse_command_line>\n");
}

void
process_connection_request(struct pb *prob,int flag)
{
	prob->sockcli=accept (request_socket, (struct sockaddr *) &client, &client_length);
	if (prob->sockcli < 0)
	{
		perror ("accept");
		return;
	}
	printf("%s %d\n",inet_ntoa (client.sin_addr), ntohs (client.sin_port));
	/*******************************/
	/*add by dp*/
	if(flag){
		read_request(prob);
		char myhost[1024];
		char *buf=prob->buffer;
		char *myp=strstr(buf,"GET http://");
		char *mypend;
		char mb[1024];
		if(myp!=NULL){
			myp+=strlen("GET http://");
			mypend=strchr(myp,'/');
			if(mypend!=NULL){
				strncpy(mb,myp,mypend-myp);
				mb[mypend-myp]='\0';
				printf("mb=%s\n",mb);
				strcpy(prob->host,mb);
			}
		}

	}
	/**************/
	if (connect_host_to_proxy (prob, remote_port) != 0)
	{
		printf ("connect_host_to_proxy: ERROR\n");
		return;
	}


}
int readcfg(char *file,const char *key,char *value)
{
	FILE *fp;
	fp=fopen(file,"r");
	char buf[1024];
	char *pe;
	while(fgets(buf,sizeof(buf),fp)!=NULL){
		pe=strchr(buf,'=');
		if(pe==NULL)
			continue;
		*pe++='\0';
		if(pe[strlen(pe)-1]=='\n')
			pe[strlen(pe)-1]='\0';
		if(strcmp(key,buf)==0){
			strcpy(value,pe);
			return 0;
		}
	}
	return -1;
}



int
main (int argc, char **argv)
{

	int connection, nfound;
	struct timeval timeout;

	char value[20];
	if(readcfg("desproxy.conf","ALIVETIME",value)==0){
		alivetime=atoi(value);
		printf("ALIVETIME=%d\n",alivetime);
	}else
		alivetime=8;
	if(readcfg("desproxy.conf","MINTIME",value)==0){
		mintime=atoi(value);
	}else
		mintime=3;
	signal (SIGPIPE, SIG_IGN);
	signal(SIGCHLD,sig_child);
	initialize_gettext ();
	print_program_version (PROGRAM_NAME, PROGRAM_VERSION);
	parse_command_line (argc, argv);

	request_socket = listen_in_TCP_port (atoi (local_port));
	printf (gettext ("Press <Control+C> to Quit\n\n"));
	mark_all_client_sockets_as_free ();

	FD_ZERO (&mask);
	FD_SET (request_socket, &mask);
	maxfd = request_socket;
	while (1)
	{
		
		rmask = mask;
		timeout.tv_sec = 5;
		timeout.tv_usec = 0;
		nfound = select (maxfd + 1, &rmask, NULL, NULL, &timeout);
		debug_printf ("%d", nfound);
		if (nfound < 0)
		{
			if (errno == EINTR)
			{
				printf (gettext ("Interrupted by system call\n"));
				continue;
			}
			perror ("select");
			exit (1);
		}

		if (FD_ISSET (request_socket, &rmask))
		{
			int pid=fork();
			if(pid<0){
				printf("fork err\n");
				exit(-1);
			}else if(pid==0){
				process_connection_request (&pb,1);
				/*child*/
				printf("----------------------------------\n");
				printf("fork a child\n");
				close(request_socket);
				child_server(&pb);
			}else{
				continue;
			}
		}
		fflush (stdout);
	}
}
int child_server(struct pb *prob)
{
	if(first==0){
		write(prob->sockproxy,prob->buffer,prob->len);
	}
	first++;
	fd_set rset,allset;
	FD_ZERO(&allset);
	FD_SET(prob->sockcli,&allset);
	FD_SET(prob->sockproxy,&allset);
	char buf[4096];
	char host[200];
	int len;
	int maxfd=prob->sockcli>prob->sockproxy?prob->sockcli+1:prob->sockproxy+1;
	struct timeval tv;
	tv.tv_sec=alivetime;
	tv.tv_usec=0;
	int n;
	char *p,*pe;
	int alllen=0;
	char buflen[10];
	while(1){
		rset=allset;
		n=select(maxfd,&rset,NULL,NULL,&tv);
		if(n<=0){
			printf("select time out!client exit %d\n",getpid());
			exit(-1);
		}
		if(FD_ISSET(prob->sockcli,&rset)){
			tv.tv_sec=alivetime;
			len=read(prob->sockcli,buf,sizeof(buf));
			if(len<0){
				printf("read client err\n");

				printf("client exit %d\n",getpid());
				exit(-1);
			}else if(len==0){
				printf("client close the socket\n");
				printf("client exit %d\n",getpid());
				exit(-1);
			}
			/*			get_host(buf,host);
			if(host[0]!='\0'&&strcmp(host,prob->host)!=0){
			strcpy(prob->host,host);
			close(prob->sockcli);
			close(prob->sockproxy);
			process_connection_request(prob,0);
			}*/
			if(write(prob->sockproxy,buf,len)<=0){
				printf("write proxy err\n");
				printf("client exit %d\n",getpid());
				exit(-1);
			}
		}
		if(FD_ISSET(prob->sockproxy,&rset)){
			tv.tv_sec=mintime;
			len=read(prob->sockproxy,buf,sizeof(buf));
			if(len<=0){
				printf("read proxy err\n");
				printf("client exit %d\n",getpid());
				exit(-1);
			}
	/*		p=strstr(buf,CONTLEN);
			if(p!=NULL){
				p+=strlen(CONTLEN);
				pe=buflen;
				while(*p>'1'&&*p<'0')
					*pe++=*p++;
				*pe='\0';
				alllen=atoi(buflen);
			}*/
			if(write(prob->sockcli,buf,len)<=0){
				printf("write cli err\n");
				printf("client exit %d\n",getpid());
				exit(-1);
			}
			/*alllen-=len;
			if(alllen<=0){
				printf("Alllen is zero!\nexit\n");
				alivetime=3;
			}*/
		}
	}
}
get_host(const char *buf,char *host)
{
	char *myp,*mypend;
	myp=strstr(buffer,"GET http://");
	if(myp!=NULL){
		myp+strlen("GET http://");
		mypend=strchr(myp,'/');
		if(mypend!=NULL){
			strncpy(host,myp,mypend-myp);
			host[mypend-myp]='\0';
		}
	}
}

void sig_child(int sig)
{
	int st;
	printf("child exit\n");
	wait(&st);
}