libcurl_tunnel.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <sys/select.h>
   4 #include <curl/curl.h>
   5 #include <getopt.h>
   6 #include <unistd.h>
   7
   8 #define _FILE_OFFSET_BITS 64 /* for curl_off_t magic */
   9 #define SIZE 655536
  10
  11 #define VERSION "0.1-dev"
  12
  13 struct gengetopt_args_info {
  14   char *proxy_arg;
  15   char *user_arg;
  16   char *dest_arg;
  17
  18   int help_given;
  19   int verbose_given;
  20   int user_given;
  21   int proxy_given;
  22   int dest_given;
  23 };
  24
  25 static void print_options(void)
  26 {
  27   printf("curltunnel\nCopyright 2007 curltunnel Project\nV " VERSION "\n"
  28       "\n"
  29       "-h       --help            Print help and exit\n"
  30       "-p       --proxy=STRING    Proxy host:port combination to connect to\n"
  31       "-u       --user=STRING     User:Password combination to send to proxy\n"
  32       "-d       --dest=STRING     Host:port combination to tunnel to\n"
  33       "-v       --verbose         Print messages about what's going on\n");
  34 }
  35
  36 static char * gengetopt_strdup(char *s)
  37 {
  38   char *n, *pn, *ps=s;
  39   while(*ps) ps++;
  40   n=(char *)malloc(1+ps-s);
  41   if(n!=NULL)
  42   {
  43     for(ps=s,pn=n;*ps;ps++,pn++)
  44       *pn = *ps;
  45     *pn=0;
  46   }
  47   return n;
  48 }
  49
  50 static int command_line_parser(int argc, char * const *argv, struct gengetopt_args_info *args_info)
  51 {
  52   int c;
  53
  54 #define clear_args()\
  55 {\
  56   args_info->help_given = 0;\
  57   args_info->verbose_given = 0;\
  58   args_info->user_given = 0;\
  59   args_info->proxy_given = 0;\
  60   args_info->dest_given = 0;\
  61   args_info->proxy_arg = NULL;\
  62   args_info->user_arg = NULL;\
  63   args_info->dest_arg = NULL;\
  64 }
  65   clear_args();
  66
  67   optarg = 0;
  68   optind = 1;
  69   opterr = 1;
  70   optopt = '?';
  71
  72   while(1)
  73   {
  74     int option_index = 0;
  75
  76     static struct option long_options[] = {
  77       { "help", 0, NULL, 'h' },
  78       { "verbose", 0, NULL, 'v' },
  79       { "proxy", 1, NULL, 'p' },
  80       { "user", 1, NULL, 'u' },
  81       { "dest", 1, NULL, 'd' },
  82       { NULL, 0, NULL, 0}
  83     };
  84
  85     c = getopt_long(argc,argv,"hvp:u:d:", long_options, &option_index);
  86
  87     if(c==-1) break;
  88
  89     switch(c)
  90     {
  91       case 'h':
  92         clear_args();
  93         print_options();
  94         exit(0);
  95       case 'v':
  96         args_info->verbose_given = !(args_info->verbose_given);
  97         if(args_info->verbose_given)
  98           printf("Verbose mode on\n");
  99         break;
 100       case 'p':
 101         if(args_info->proxy_given)
 102         {
 103           fprintf(stderr,"curltunnel: `--proxy' (`-p') option given more than once\n");
 104           clear_args();
 105           exit(1);
 106         }
 107         args_info->proxy_given = 1;
 108         args_info->proxy_arg = gengetopt_strdup(optarg);
 109         break;
 110       case 'u':
 111         if(args_info->user_given)
 112         {
 113           fprintf(stderr,"curltunnel: `--user' (`-u') option given more than once\n");
 114           clear_args();
 115           exit(1);
 116         }
 117         args_info->user_given = 1;
 118         args_info->user_arg = gengetopt_strdup(optarg);
 119         break;
 120       case 'd':
 121         if(args_info->dest_given)
 122         {
 123           fprintf(stderr,"curltunnel: `--dest' (`-d') option given more than once\n");
 124           clear_args();
 125           exit(1);
 126         }
 127         args_info->dest_given = 1;
 128         args_info->dest_arg = gengetopt_strdup(optarg);
 129         break;
 130     }
 131   }
 132
 133   if(!args_info->proxy_given || !args_info->dest_given)
 134   {
 135     clear_args();
 136     print_options();
 137     exit(0);
 138   }
 139
 140   return 0;
 141 }
 142
 143 static int fd_read(int fd, void *buf, size_t len)
 144 {
 145   int bytes_read;
 146   bytes_read = read(fd,buf,len);
 147   return bytes_read;
 148 }
 149
 150 static int fd_write(int fd, void *buf, size_t len)
 151 {
 152   int bytes_written;
 153   bytes_written = write(fd,buf,len);
 154   return bytes_written;
 155 }
 156
 157 static int fdcopy(int fdin, int fdout)
 158 {
 159   char buf[SIZE];
 160   int n;
 161
 162   if((n=fd_read(fdin,buf,SIZE))<0)
 163   {
 164     fprintf(stderr,"Read Error\n");
 165     exit(1);
 166   }
 167
 168   if(n==0)
 169     return 1;
 170
 171   if(fd_write(fdout,buf,n)!=n)
 172   {
 173     fprintf(stderr,"Write Error\n");
 174     exit(1);
 175   }
 176
 177   return 0;
 178 }
 179
 180 static void wait_and_act(int sockfd, int verbose)
 181 {
 182   struct timeval timeout;
 183   int rc; /* select() return code */
 184   long timeout_ms = 10000;
 185
 186   fd_set fdread;
 187   fd_set fdwrite;
 188   fd_set fdexcep;
 189   int maxfd=sockfd;
 190
 191   while(1==1)
 192   {
 193     FD_ZERO(&fdread);
 194     FD_ZERO(&fdwrite);
 195     FD_ZERO(&fdexcep);
 196
 197     /* set timeout to wait */
 198     timeout.tv_sec = timeout_ms/1000;
 199     timeout.tv_usec = (timeout_ms%1000)*1000;
 200
 201     FD_SET(fileno(stdin), &fdread);
 202     FD_SET(sockfd, &fdread);
 203     /* FD_SET(sockfd, &fdwrite); */
 204
 205     rc = select(maxfd+1,
 206           (fd_set *)&fdread,
 207           (fd_set *)&fdwrite,
 208           (fd_set *)&fdexcep, &timeout);
 209
 210     if(rc==-1) {
 211       /* select error */
 212       fprintf(stderr,"select() error\n");
 213       break;
 214     }
 215     if(rc==0){
 216       /* timeout! */
 217       /* fprintf(stderr,"Timeout\n"); */
 218       if(verbose)
 219           fprintf(stderr,"VERBOSE: Timeout after %ldms\n", timeout_ms);
 220     }
 221     else
 222     {
 223       /* use FD_ISSET() to check what happened, then read/write accordingly */
 224       if (FD_ISSET(fileno(stdin), &fdread))
 225       {
 226         rc=fdcopy(fileno(stdin),sockfd);
 227         if(!rc)
 228           break;
 229         if(verbose)
 230           fprintf(stderr,"VERBOSE: Sent %d bytes from stdin to socket\n", rc);
 231       }
 232       if (FD_ISSET(sockfd,&fdread))
 233       {
 234         rc=fdcopy(sockfd,fileno(stdout));
 235         if(!rc)
 236           break;
 237         if(verbose)
 238           fprintf(stderr,"VERBOSE: Sent %d bytes from socket to stdin\n", rc);
 239       }
 240     }
 241   }
 242 }
 243
 244 int main(int argc, char *argv[])
 245 {
 246   CURLcode ret;
 247   long sckt;
 248   struct gengetopt_args_info args_info;
 249
 250   command_line_parser(argc,argv,&args_info);
 251
 252   CURL *hnd = curl_easy_init();
 253
 254   curl_easy_setopt(hnd, CURLOPT_URL, args_info.dest_arg);
 255   curl_easy_setopt(hnd, CURLOPT_PROXY, args_info.proxy_arg);
 256   curl_easy_setopt(hnd, CURLOPT_PROXYUSERPWD, args_info.user_arg);
 257   curl_easy_setopt(hnd, CURLOPT_USERAGENT, "curltunnel/" VERSION);
 258   curl_easy_setopt(hnd, CURLOPT_HTTPPROXYTUNNEL, 1);
 259   curl_easy_setopt(hnd, CURLOPT_CONNECT_ONLY, 1);
 260   if(args_info.verbose_given)
 261     curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1);
 262   ret = curl_easy_perform(hnd);
 263
 264   if(ret == CURLE_OK)
 265   {
 266     /* Extract socket, and select() */
 267     ret = curl_easy_getinfo(hnd, CURLINFO_LASTSOCKET, &sckt);
 268   }
 269     if((sckt==-1) || ret){
 270       fprintf(stderr,"[ERR] Couldn't get socket");
 271     return 1;
 272   }
 273
 274   wait_and_act((int)sckt, args_info.verbose_given);
 275
 276   curl_easy_cleanup(hnd);
 277   return 0;
 278 }