/***************************************************************************
                          core.c  -  description
                             -------------------
    begin                : Tue May 14 2002
    copyright            :  netcreature (C) 2002
    email                : netcreature@users.sourceforge.net
 ***************************************************************************/
/*     GPL */
/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netdb.h>

#include <sys/utsname.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <time.h>
#include <sys/time.h>
#include <stdarg.h>
#include "core.h"

extern int tcp_read_time_out;
extern int tcp_connect_time_out;
extern int proxychains_quiet_mode;

static const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static int poll_retry(struct pollfd *fds, nfds_t nfsd, int timeout) 
{
  int ret;
  int time_remain = timeout;
  int time_elapsed = 0;

  struct timeval start_time;
  struct timeval tv;

  gettimeofday(&start_time, NULL);

  do 
  {
    //printf("Retry %d\n", time_remain);
    ret = poll(fds, nfsd, time_remain);
    gettimeofday(&tv, NULL);
    time_elapsed =  ((tv.tv_sec - start_time.tv_sec) * 1000 + (tv.tv_usec - start_time.tv_usec) / 1000);
    //printf("Time elapsed %d\n", time_elapsed);
    time_remain = timeout - time_elapsed;
  }
  while (ret == -1 && errno == EINTR && time_remain > 0);
  //if (ret == -1)
  //printf("Return %d %d %s\n", ret, errno, strerror(errno));
  return ret;
}


static void encode_base_64(char* src,char* dest,int max_len)
{
	int n,l,i;
 	l=strlen(src);
	max_len=(max_len-1)/4;
	for ( i=0;i<max_len;i++,src+=3,l-=3)
	{
		switch (l) {
		case 0:
			break;
		case 1:
			n=src[0] << 16;
			*dest++=base64[(n >> 18) & 077];
			*dest++=base64[(n >> 12) & 077];
			*dest++='=';
			*dest++='=';
			break;
		case 2:
			n=src[0] << 16 | src[1] << 8;
			*dest++=base64[(n >> 18) & 077];
			*dest++=base64[(n >> 12) & 077];
			*dest++=base64[(n >> 6) & 077];
			*dest++='=';
			break;
		default:
			n=src[0] << 16 | src[1] << 8 | src[2];
			*dest++=base64[(n >> 18) & 077];
			*dest++=base64[(n >> 12) & 077];
			*dest++=base64[(n >> 6) & 077];
			*dest++=base64[n & 077];
		}
		if (l<3) break;
	}
	*dest++=0;
}

#define LOG_BUFF 1024*20

int proxychains_write_log(char *str,...)
{
    char buff[LOG_BUFF];
    va_list arglist;
    FILE * log_file;
    log_file=stderr;
    if (!proxychains_quiet_mode)
    {
        va_start(arglist,str);
        vsprintf(buff,str,arglist);
        va_end(arglist);
        fprintf(log_file,"%s",buff);
        fflush(log_file);
    }

        return EXIT_SUCCESS;
}

static int write_n_bytes(int fd,char *buff,size_t size)
{
	int i=0;
	size_t wrote=0;
	for(;;)	{
		i = write(fd,&buff[wrote],size-wrote);
		if(i<=0)
			return i;
		wrote += i;
		if(wrote==size)
			return wrote;
	}
}

static int read_n_bytes(int fd,char *buff, size_t size)
{
	int ready;
	size_t i;
	struct pollfd pfd[1];

	pfd[0].fd=fd;
	pfd[0].events=POLLIN;
	for(i=0; i < size; i++) {  
		pfd[0].revents = 0;
		ready = poll_retry(pfd, 1, tcp_read_time_out);
		if(ready != 1 || !(pfd[0].revents&POLLIN) || 1 != read(fd,&buff[i],1))
			return -1;
	}
	return (int) size;
}

static int timed_connect(int sock, const struct sockaddr *addr, socklen_t len)
{
	int ret, value;
	socklen_t value_len;
 	struct pollfd pfd[1];

	pfd[0].fd=sock;
	pfd[0].events=POLLOUT;	
	fcntl(sock, F_SETFL, O_NONBLOCK);
  	ret = true_connect(sock, addr,  len);
#ifdef DEBUG
	if(ret == -1) perror("true_connect");
	printf("\nconnect ret=%d\n",ret);
	
	fflush(stdout);
#endif
  	if(ret==-1 && errno==EINPROGRESS) {
		ret=poll_retry(pfd,1,tcp_connect_time_out);
#ifdef DEBUG
		printf("\npoll ret=%d\n",ret);fflush(stdout);
#endif
	      	if(ret == 1) {
			value_len=sizeof(socklen_t);
			getsockopt(sock,SOL_SOCKET,SO_ERROR,&value,&value_len) ;
#ifdef DEBUG
			printf("\nvalue=%d\n",value);fflush(stdout);
#endif
        	       	if(!value)
				ret=0;
			else
				ret=-1;
		} else {
        		      	ret=-1;
		}
	} else {
		if (ret != 0)
			ret=-1;
	} 	

	fcntl(sock, F_SETFL, !O_NONBLOCK);
	return ret;
}

static int tunnel_to(int sock, unsigned int ip, unsigned short port, proxy_type pt,char *user,char *pass)
{
#ifdef DEBUG
	PDEBUG("tunnel to\n");
#endif	
        int len;
        char buff[BUFF_SIZE];
        memset (buff, 0, sizeof(buff));
        switch(pt)
        {
        	case HTTP_TYPE:
         		{
             		sprintf(buff,"CONNECT %s:%d HTTP/1.0\r\n",
			        inet_ntoa( * (struct in_addr *) &ip),
			        ntohs(port));
           			if (user[0])
                		{
					char src[256];
     					char dst[512];
					strcpy(src,user);
					strcat(src,":");
					strcat(src,pass);
					encode_base_64(src,dst,512);
					strcat(buff,"Proxy-Authorization: Basic ");
					strcat(buff,dst);
					strcat(buff,"\r\n\r\n");
				}
    				else
					strcat(buff,"\r\n");
			
           			len=strlen(buff);

			        if(len!=send(sock,buff,len,0))
			                return SOCKET_ERROR;
			
           			memset(buff, 0, sizeof(buff));
                        len=0 ;
      			 // read header byte by byte.
			       while(len<BUFF_SIZE)
			       {
			                if(1==read_n_bytes(sock,buff+len,1))
			                        len++;
			                else
			                        return SOCKET_ERROR;
			                if (    len > 4     &&
		                        	buff[len-1]=='\n'  &&
			                        buff[len-2]=='\r'  &&
			                        buff[len-3]=='\n'  &&
			                        buff[len-4]=='\r'  )
		                        break;
			       }

			       // if not ok (200) or response greather than BUFF_SIZE return BLOCKED;
			       if (     (len==BUFF_SIZE)  ||
			                ! (     buff[9] =='2'         &&
			                        buff[10]=='0'        &&
			                        buff[11]=='0'         ))
                                  return BLOCKED;
			       return SUCCESS;
           		}
            	break;
            case SOCKS4_TYPE:
            	{
               		memset(buff,0,sizeof(buff));
                 		buff[0]=4; // socks version
  				buff[1]=1; // connect command
				memcpy(&buff[2],&port,2); // dest port
				memcpy(&buff[4],&ip,4); // dest host
				len=strlen(user)+1; // username
    				if(len>1)	
         				strcpy(&buff[8],user);
				if((len+8)!=write_n_bytes(sock,buff,(8+len)))
					return SOCKET_ERROR;

 				if(8!=read_n_bytes(sock,buff,8))
					return SOCKET_ERROR;
            	
				if (buff[0]!=0||buff[1]!=90)
					return BLOCKED;
     				
         			return SUCCESS;
               	}
                	break;
            case SOCKS5_TYPE:
            	{
               		if(user)
                 		{
                 			buff[0]=5;   //version
					buff[1]=2;	//nomber of methods
					buff[2]=0;   // no auth method
	    				buff[3]=2;  /// auth method -> username / password
                              if(4!=write_n_bytes(sock,buff,4))
					 	return SOCKET_ERROR;
       			}
            		else
                		{
            			buff[0]=5;   //version
					buff[1]=1;	//nomber of methods
					buff[2]=0;   // no auth method
                              if(3!=write_n_bytes(sock,buff,3))
					 	return SOCKET_ERROR;
       			}

				memset(buff,0,sizeof(buff));

				if(2!=read_n_bytes(sock,buff,2))
			 		return SOCKET_ERROR;
			
      			if (buff[0]!=5||(buff[1]!=0&&buff[1]!=2))
         			{
        				if((buff[0]==0x05)&&(buff[1]==(char)0xFF))
             						return BLOCKED;
						else
							return SOCKET_ERROR;
          			}
          			
          			if (buff[1]==2)
               		{
					// authentication
					char in[2];
     					char out[515]; char* cur=out;
					int c;
     					*cur++=1; // version
					c=strlen(user);
					*cur++=c;
					strncpy(cur,user,c);
					cur+=c;
					c=strlen(pass);
					*cur++=c;
					strncpy(cur,pass,c);
					cur+=c;
					
     					if((cur-out)!=write_n_bytes(sock,out,cur-out))
					 	return SOCKET_ERROR;
     					
          				
					if(2!=read_n_bytes(sock,in,2))
			 			return SOCKET_ERROR;
					if(in[0]!=1||in[1]!=0)
       				{
						if(in[0]!=1)
      						return SOCKET_ERROR;
						else
      						return BLOCKED;
					}
				}	

     				buff[0]=5;       // version
				buff[1]=1;       // connect
				buff[2]=0;       // reserved
				buff[3]=1;       // ip v4

			 	memcpy(&buff[4],&ip,4); // dest host
				memcpy(&buff[8],&port,2); // dest port
				

			      if(10!=write_n_bytes(sock,buff,10))
					return SOCKET_ERROR;
		
			      if(4!=read_n_bytes(sock,buff,4))
					return SOCKET_ERROR;

				if (buff[0]!=5||buff[1]!=0)
			      	return SOCKET_ERROR;

			  	switch (buff[3])
			      {
					case 1: len=4;  break;
					case 4: len=16; break;
					case 3: len=0;
			  			if(1!=read_n_bytes(sock,(char*)&len,1))
			 				return SOCKET_ERROR;
        					break;
					default:
						return SOCKET_ERROR;
				}

     				if((len+2)!=read_n_bytes(sock,buff,(len+2)))
					return SOCKET_ERROR;

				return SUCCESS;
                	}
                	break;	

        }

return SOCKET_ERROR;
}

static int start_chain(int *fd, proxy_data *pd, char* begin_mark)
{
	struct sockaddr_in addr;
	
	*fd=socket(PF_INET,SOCK_STREAM,0);
	if(*fd==-1)
		goto error;
	
	proxychains_write_log("%s-<>-%s:%d-",
				begin_mark,
				inet_ntoa(*(struct in_addr*)&pd->ip),
				htons(pd->port));
	pd->ps=PLAY_STATE;
	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_addr.s_addr = pd->ip;
	addr.sin_port = pd->port;
	if (timed_connect (*fd ,(struct sockaddr*)&addr,sizeof(addr))) {
		pd->ps=DOWN_STATE;
		goto error1;
	}
	pd->ps=BUSY_STATE;
	return SUCCESS;
error1:
	proxychains_write_log("<--timeout\n");
error:
	if(*fd!=-1)
		close(*fd);
	return SOCKET_ERROR;
}

static proxy_data * select_proxy(select_type how, 
		proxy_data *pd, unsigned int proxy_count, unsigned int *offset)
{
	unsigned int i=0, k=0;
	if(*offset >= proxy_count)
		return NULL;
	switch(how) {
		case RANDOMLY:
			srand(time(NULL));
			do {
				k++;
				i = 0 + (unsigned int) (proxy_count * 1.0 * rand()/
						(RAND_MAX + 1.0));
			} while (pd[i].ps != PLAY_STATE && k < proxy_count*100 );
		break;
		case FIFOLY:
			for(i=*offset; i<proxy_count; i++) {
				if(pd[i].ps == PLAY_STATE) {
					*offset = i;
					break;
				}
			}
		default:
		break;
	}
	if (i >= proxy_count)
		i = 0;
	return (pd[i].ps == PLAY_STATE)? &pd[i] : NULL;
}


static void release_all(proxy_data *pd, unsigned int proxy_count)
{
	unsigned int i;
	for(i=0; i<proxy_count; i++)
		pd[i].ps = PLAY_STATE;
	return;
}

static void release_busy(proxy_data *pd, unsigned int proxy_count)
{
	unsigned int i;
	for(i=0; i<proxy_count; i++)
		if(pd[i].ps == BUSY_STATE)
			pd[i].ps = PLAY_STATE;
	return;
}

static unsigned int calc_alive(proxy_data *pd, unsigned int proxy_count)
{
	unsigned int i;
	int alive_count=0;
	release_busy(pd, proxy_count);
	for(i=0; i<proxy_count; i++)
		if(pd[i].ps == PLAY_STATE)
			alive_count++;
	return alive_count;
}


static int chain_step(int ns, proxy_data *pfrom, proxy_data *pto)
{
	int retcode=-1;
#ifdef DEBUG
	PDEBUG("chain_step()\n");
#endif
	
	proxychains_write_log("<>-%s:%d-", 
			inet_ntoa(*(struct in_addr*)&pto->ip),
			htons(pto->port));
	retcode = 
		tunnel_to(ns, pto->ip, pto->port, pfrom->pt, pfrom->user, 
				pfrom->pass);
	switch(retcode) {
		case SUCCESS:
			pto->ps=BUSY_STATE;
			break;
		case BLOCKED:
			pto->ps=BLOCKED_STATE;
			proxychains_write_log("<--denied\n");
			close(ns);
			break;
		case SOCKET_ERROR:
			pto->ps=DOWN_STATE;
			proxychains_write_log("<--timeout\n");
			close(ns);
			break;
	}
	return retcode;
}

int connect_proxy_chain( int sock, unsigned int target_ip, 
		unsigned short target_port, proxy_data *pd, 
		unsigned int proxy_count, chain_type ct, unsigned int max_chain )
{
	proxy_data p4;
	proxy_data *p1,*p2,*p3;
	int ns=-1;
	unsigned int offset=0;
	unsigned int alive_count=0;
	unsigned int curr_len=0;

#define TP "<>"
#define DT "|D-chain|"
#define ST "|S-chain|"
#define RT "|R-chain|"
	
	p3=&p4;
#ifdef DEBUG
	PDEBUG("connect_proxy_chain\n");
#endif
	
again:

	switch(ct)  {
		case DYNAMIC_TYPE:
		alive_count=calc_alive(pd,proxy_count);
		offset=0;
		do {
			if(!(p1=select_proxy(FIFOLY,pd,proxy_count,&offset)))
				goto error_more;
		} while(SUCCESS!=start_chain(&ns,p1,DT) && offset < proxy_count);
		for(;;) {
			p2=select_proxy(FIFOLY,pd,proxy_count,&offset);
			if(!p2)
				break;
			if(SUCCESS!=chain_step(ns,p1,p2)) {
				#ifdef DEBUG
				PDEBUG("GOTO AGAIN 1\n");
				#endif
				goto again;
			}
			p1=p2;
		}
		proxychains_write_log(TP);
		p3->ip=target_ip;
		p3->port=target_port;
		if(SUCCESS!=chain_step(ns,p1,p3))
			goto error;
		break;

	case STRICT_TYPE:
		alive_count=calc_alive(pd, proxy_count);
		offset=0;
		if(!(p1=select_proxy(FIFOLY, pd, proxy_count, &offset))) {
			#ifdef DEBUG
			PDEBUG("select_proxy failed\n");
			#endif
			goto error_strict;
		}
		if(SUCCESS!=start_chain(&ns, p1, ST)) {
			#ifdef DEBUG
			PDEBUG("start_chain failed\n");
			#endif
			goto error_strict;
		}
		while(offset < proxy_count) {
			if(!(p2 = select_proxy(FIFOLY, pd, proxy_count, &offset)))
				break;
			if(SUCCESS!=chain_step(ns, p1, p2)) {
				#ifdef DEBUG
				PDEBUG("chain_step failed\n");
				#endif
				goto error_strict;
			}
			p1=p2;
		}
		proxychains_write_log(TP);
		p3->ip=target_ip;
		p3->port=target_port;
		if(SUCCESS!=chain_step(ns,p1,p3))
			goto error;
		break;
		
	case RANDOM_TYPE:
		alive_count=calc_alive(pd,proxy_count);
		if(alive_count<max_chain)
			goto error_more;
		curr_len=offset=0;
		do {
			if(!(p1=select_proxy(RANDOMLY,pd,proxy_count,&offset)))
				goto error_more;
		} while(SUCCESS!=start_chain(&ns,p1,RT) && offset<max_chain);
		while(++curr_len<max_chain) {
			if(!(p2=select_proxy(RANDOMLY,pd,proxy_count,&offset)))
				goto error_more;
			if(SUCCESS!=chain_step(ns,p1,p2)) {
				#ifdef DEBUG
				PDEBUG("GOTO AGAIN 2\n");
				#endif
				goto again;
			}	
			p1=p2;
		}
		proxychains_write_log(TP);
		p3->ip=target_ip;
		p3->port=target_port;
		if(SUCCESS!=chain_step(ns,p1,p3))
			goto error;
			
	}

	proxychains_write_log("<><>-OK\n");
	dup2(ns,sock);
	close(ns);
	return 0;
error:
	if(ns!=-1)
		close(ns);
	errno = ECONNREFUSED;  // for nmap ;)
	return -1;
	
error_more:
	proxychains_write_log("\n!!!need more proxies!!!\n");
error_strict:
	#ifdef DEBUG
	PDEBUG("error\n");
	#endif
	release_all(pd,proxy_count);
	if(ns!=-1)
		close(ns);
	errno = ETIMEDOUT;
	return -1;
}

static struct hostent hostent_space;
static in_addr_t resolved_addr;
static char* resolved_addr_p;
static char addr_name[1024*8];
struct hostent* proxy_gethostbyname(const char *name)
{
	int pipe_fd[2];
	char buff[256];
	in_addr_t addr;
	pid_t pid;
	int status;
	struct hostent* hp;

	hostent_space.h_addr_list = &resolved_addr_p;
	*hostent_space.h_addr_list = (char*)&resolved_addr;
	resolved_addr = 0;
	
	gethostname(buff,sizeof(buff));
	if(!strcmp(buff,name))
		goto got_buff;

	memset(buff, 0, sizeof(buff));
	
	// TODO: this works only once, so cache it  ...
	// 	 later
	while ((hp=gethostent()))
		if (!strcmp(hp->h_name,name)) 
			return hp; 
	
	if(pipe(pipe_fd))
		goto err;
	pid = fork();
	switch(pid) {
	
		case 0: // child
			proxychains_write_log("|DNS-request| %s \n", name);
			dup2(pipe_fd[1],1);
			//dup2(pipe_fd[1],2);
		//	putenv("LD_PRELOAD=");
			execlp("proxyresolv","proxyresolv",name,NULL);
			perror("can't exec proxyresolv");
			exit(2);

		case -1: //error
			close(pipe_fd[0]);
			close(pipe_fd[1]);
			perror("can't fork");
			goto err;
		
		default:
			close(pipe_fd[1]);
			waitpid(pid, &status, 0);
			read(pipe_fd[0],&buff,sizeof(buff));
			close(pipe_fd[0]);
got_buff:
			addr = inet_addr(buff);
			if (addr == (in_addr_t) (-1))
				goto err_dns;
			memcpy(*(hostent_space.h_addr_list),
						&addr ,sizeof(struct in_addr));
			hostent_space.h_name = addr_name;
			hostent_space.h_length = sizeof (in_addr_t);
	}
	proxychains_write_log("|DNS-response| %s is %s\n",
			name, inet_ntoa(*(struct in_addr*)&addr));
	return &hostent_space;
err_dns:
	proxychains_write_log("|DNS-response|: %s does not exist\n", name);
	perror("err_dns");
err:
	return NULL;
}
int proxy_getaddrinfo(const char *node, const char *service,
		const struct addrinfo *hints,
		struct addrinfo **res)
{
	struct servent *se = NULL;
	struct hostent *hp = NULL;
	struct sockaddr* sockaddr_space = NULL;
	struct addrinfo*  addrinfo_space = NULL;
	
//	printf("proxy_getaddrinfo node %s service %s\n",node,service);
	addrinfo_space = malloc(sizeof(struct addrinfo));
	if(!addrinfo_space)
		goto err1;
	sockaddr_space = malloc(sizeof(struct sockaddr));
	if(!sockaddr_space)
		goto err2;
	memset(sockaddr_space, 0, sizeof(*sockaddr_space));
	memset(addrinfo_space, 0, sizeof(*addrinfo_space));
	if (node &&
	    !inet_aton(node,&((struct sockaddr_in*)sockaddr_space)->sin_addr)) {
		hp = proxy_gethostbyname(node);
		if (hp) 
			memcpy(&((struct sockaddr_in*)sockaddr_space)->sin_addr,
				*(hp->h_addr_list),
				sizeof(in_addr_t));
		else
			goto err3;
	}
	if (service)
		se = getservbyname(service, NULL);
	
	if (!se) {
		((struct sockaddr_in*)sockaddr_space)->sin_port = 
			htons(atoi(service?:"0"));
	} else 
		((struct sockaddr_in*)sockaddr_space)->sin_port = se->s_port;

	*res = addrinfo_space;
	(*res)->ai_addr = sockaddr_space;
	if (node)
		strcpy(addr_name, node);
	(*res)->ai_canonname = addr_name;
	(*res)->ai_next = NULL;
	(*res)->ai_family = sockaddr_space->sa_family = AF_INET;
	(*res)->ai_socktype = hints->ai_socktype;
	(*res)->ai_flags = hints->ai_flags;
	(*res)->ai_protocol = hints->ai_protocol;
	(*res)->ai_addrlen = sizeof(*sockaddr_space);
	goto out;
err3:
	free(sockaddr_space);
err2:
	free(addrinfo_space);
err1:
	return 1;
out:
	return 0;
}