sys/src/cmd/ip/socksd.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <ip.h>
   4
   5 int socksver;
   6 char inside[128];
   7 char outside[128];
   8
   9 int
  10 str2addr(char *s, uchar *a)
  11 {
  12         uchar *a0, ip[16];
  13         char *p;
  14
  15         if((s = strchr(s, '!')) == nil)
  16                 return 0;
  17         if((p = strchr(++s, '!')) == nil)
  18                 return 0;
  19         if(strchr(++p, '!') != nil)
  20                 return 0;
  21         if(parseip(ip, s) == -1)
  22                 return 0;
  23
  24         a0 = a;
  25         if(socksver == 4){
  26                 a += 2;
  27                 hnputs(a, atoi(p));
  28                 a += 2;
  29                 v6tov4(a, ip);
  30                 a += 4;
  31         } else {
  32                 a += 3;
  33                 if(isv4(ip)){
  34                         *a++ = 0x01;
  35                         v6tov4(a, ip);
  36                         a += 4;
  37                 } else {
  38                         *a++ = 0x04;
  39                         memmove(a, ip, 16);
  40                         a += 16;
  41                 }
  42                 hnputs(a, atoi(p));
  43                 a += 2;
  44         }
  45         return a - a0;
  46 }
  47
  48 char*
  49 addr2str(char *proto, uchar *a){
  50         static char s[128];
  51         uchar ip[16];
  52         int n, port;
  53
  54         if(socksver == 4){
  55                 a += 2;
  56                 port = nhgets(a);
  57                 a += 2;
  58                 if((a[0] | a[1] | a[2]) == 0 && a[3]){
  59                         a += 4;
  60                         a += strlen((char*)a)+1;
  61                         snprint(s, sizeof(s), "%s!%s!%d", proto, (char*)a, port);
  62                         return s;
  63                 }
  64                 v4tov6(ip, a);
  65         } else {
  66                 a += 3;
  67                 switch(*a++){
  68                 default:
  69                         return nil;
  70                 case 0x01:
  71                         v4tov6(ip, a);
  72                         port = nhgets(a+4);
  73                         break;
  74                 case 0x04:
  75                         memmove(ip, a, 16);
  76                         port = nhgets(a+16);
  77                         break;
  78                 case 0x03:
  79                         n = *a++;
  80                         port = nhgets(a+n);
  81                         snprint(s, sizeof(s), "%s!%.*s!%d", proto, n, (char*)a, port);
  82                         return s;
  83                 }
  84         }
  85         snprint(s, sizeof(s), "%s!%I!%d", proto, ip, port);
  86         return s;
  87 }
  88
  89 int
  90 udprelay(int fd, char *dir)
  91 {
  92         struct {
  93                 Udphdr;
  94                 uchar data[8*1024];
  95         } msg;
  96         char addr[128], ldir[40];
  97         int r, n, rfd, cfd;
  98         uchar *p;
  99
 100         snprint(addr, sizeof(addr), "%s/udp!*!0", outside);
 101         if((cfd = announce(addr, ldir)) < 0)
 102                 return -1;
 103         if(write(cfd, "headers", 7) != 7)
 104                 return -1;
 105         strcat(ldir, "/data");
 106         if((rfd = open(ldir, ORDWR)) < 0)
 107                 return -1;
 108         close(cfd);
 109
 110         if((r = rfork(RFMEM|RFPROC|RFNOWAIT)) <= 0)
 111                 return r;
 112
 113         if((cfd = listen(dir, ldir)) < 0)
 114                 return -1;
 115         close(fd);      /* close inside udp server */
 116         if((fd = accept(cfd, ldir)) < 0)
 117                 return -1;
 118
 119         switch(rfork(RFMEM|RFPROC|RFNOWAIT)){
 120         case -1:
 121                 return -1;
 122         case 0:
 123                 while((r = read(fd, msg.data, sizeof(msg.data))) > 0){
 124                         if(r < 4)
 125                                 continue;
 126                         p = msg.data;
 127                         if(p[0] | p[1] | p[2])
 128                                 continue;
 129                         p += 3;
 130                         switch(*p++){
 131                         default:
 132                                 continue;
 133                         case 0x01:
 134                                 r -= 2+1+1+4+2;
 135                                 if(r < 0)
 136                                         continue;
 137                                 v4tov6(msg.raddr, p);
 138                                 p += 4;
 139                                 break;
 140                         case 0x04:
 141                                 r -= 2+1+1+16+2;
 142                                 if(r < 0)
 143                                         continue;
 144                                 memmove(msg.raddr, p, 16);
 145                                 p += 16;
 146                                 break;
 147                         }
 148                         memmove(msg.rport, p, 2);
 149                         p += 2;
 150                         memmove(msg.data, p, r);
 151                         write(rfd, &msg, sizeof(Udphdr)+r);
 152                 }
 153                 break;
 154         default:
 155                 while((r = read(rfd, &msg, sizeof(msg))) > 0){
 156                         r -= sizeof(Udphdr);
 157                         if(r < 0)
 158                                 continue;
 159                         p = msg.data;
 160                         if(isv4(msg.raddr))
 161                                 n = 2+1+1+4+2;
 162                         else
 163                                 n = 2+1+1+16+2;
 164                         if(r+n > sizeof(msg.data))
 165                                 r = sizeof(msg.data)-n;
 166                         memmove(p+n, p, r);
 167                         *p++ = 0;
 168                         *p++ = 0;
 169                         *p++ = 0;
 170                         if(isv4(msg.raddr)){
 171                                 *p++ = 0x01;
 172                                 v6tov4(p, msg.raddr);
 173                                 p += 4;
 174                         } else {
 175                                 *p++ = 0x04;
 176                                 memmove(p, msg.raddr, 16);
 177                                 p += 16;
 178                         }
 179                         memmove(p, msg.rport, 2);
 180                         r += n;
 181                         write(fd, msg.data, r);
 182                 }
 183         }
 184         return -1;
 185 }
 186
 187 int
 188 sockerr(int err)
 189 {
 190         /* general error */
 191         if(socksver == 4)
 192                 return err ? 0x5b : 0x5a;
 193         else
 194                 return err != 0;
 195 }
 196
 197 void
 198 main(int argc, char *argv[])
 199 {
 200         uchar buf[8*1024], *p;
 201         char addr[128], dir[40], ldir[40], *s;
 202         int cmd, fd, cfd, n;
 203         NetConnInfo *nc;
 204
 205         fmtinstall('I', eipfmt);
 206
 207         setnetmtpt(inside, sizeof(inside), 0);
 208         setnetmtpt(outside, sizeof(outside), 0);
 209         ARGBEGIN {
 210         case 'x':
 211                 setnetmtpt(inside, sizeof(inside), ARGF());
 212                 break;
 213         case 'o':
 214                 setnetmtpt(outside, sizeof(outside), ARGF());
 215                 break;
 216         } ARGEND;
 217
 218         /* ver+cmd or ver+nmethod */
 219         if(readn(0, buf, 2) != 2)
 220                 return;
 221         socksver = buf[0];
 222         if(socksver < 4)
 223                 return;
 224         if(socksver > 5)
 225                 socksver = 5;
 226
 227         if(socksver == 4){
 228                 /* port+ip4 */
 229                 if(readn(0, buf+2, 2+4) != 2+4)
 230                         return;
 231                 /* +user\0 */
 232                 for(p = buf+2+2+4;; p++){
 233                         if(p >= buf+sizeof(buf))
 234                                 return;
 235                         if(read(0, p, 1) != 1)
 236                                 return;
 237                         if(*p == 0)
 238                                 break;
 239                 }
 240                 /* socks 4a dom hack */
 241                 if((buf[4] | buf[5] | buf[6]) == 0 && buf[7]){
 242                         /* +dom\0 */
 243                         for(++p;; p++){
 244                                 if(p >= buf+sizeof(buf))
 245                                         return;
 246                                 if(read(0, p, 1) != 1)
 247                                         return;
 248                                 if(*p == 0)
 249                                         break;
 250                         }
 251                 }
 252         } else {
 253                 /* nmethod */
 254                 if((n = buf[1]) > 0)
 255                         if(readn(0, buf+2, n) != n)
 256                                 return;
 257
 258                 /* ver+method */
 259                 buf[0] = socksver;
 260                 buf[1] = 0x00;  /* no authentication required */
 261                 if(write(1, buf, 2) != 2)
 262                         return;
 263
 264                 /* ver+cmd+res+atyp */
 265                 if(readn(0, buf, 4) != 4)
 266                         return;
 267                 switch(buf[3]){
 268                 default:
 269                         return;
 270                 case 0x01:      /* +ipv4 */
 271                         if(readn(0, buf+4, 4+2) != 4+2)
 272                                 return;
 273                         break;
 274                 case 0x03:      /* +len+dom[len] */
 275                         if(readn(0, buf+4, 1) != 1)
 276                                 return;
 277                         if((n = buf[4]) == 0)
 278                                 return;
 279                         if(readn(0, buf+5, n+2) != n+2)
 280                                 return;
 281                         break;
 282                 case 0x04:      /* +ipv6 */
 283                         if(readn(0, buf+4, 16+2) != 16+2)
 284                                 return;
 285                         break;
 286                 }
 287         }
 288
 289         dir[0] = 0;
 290         fd = cfd = -1;
 291         cmd = buf[1];
 292         switch(cmd){
 293         case 0x01:      /* CONNECT */
 294                 snprint(addr, sizeof(addr), "%s/tcp", outside);
 295                 if((s = addr2str(addr, buf)) == nil)
 296                         break;
 297                 alarm(30000);
 298                 fd = dial(s, 0, dir, &cfd);
 299                 alarm(0);
 300                 break;
 301         case 0x02:      /* BIND */
 302                 if(myipaddr(buf, outside) < 0)
 303                         break;
 304                 snprint(addr, sizeof(addr), "%s/tcp!%I!0", outside, buf);
 305                 fd = announce(addr, dir);
 306                 break;
 307         case 0x03:      /* UDP */
 308                 if(myipaddr(buf, inside) < 0)
 309                         break;
 310                 snprint(addr, sizeof(addr), "%s/udp!%I!0", inside, buf);
 311                 fd = announce(addr, dir);
 312                 break;
 313         }
 314
 315 Reply:
 316         /* reply */
 317         buf[1] = sockerr(fd < 0);                       /* status */
 318         if(socksver == 4){
 319                 buf[0] = 0x00;                          /* vc */
 320                 if(fd < 0){
 321                         memset(buf+2, 0, 2+4);
 322                         write(1, buf, 2+2+4);
 323                         return;
 324                 }
 325         } else {
 326                 buf[0] = socksver;                      /* ver */
 327                 buf[2] = 0x00;                          /* res */
 328                 if(fd < 0){
 329                         buf[3] = 0x01;                  /* atyp */
 330                         memset(buf+4, 0, 4+2);
 331                         write(1, buf, 4+4+2);
 332                         return;
 333                 }
 334         }
 335         if((nc = getnetconninfo(dir, cfd)) == nil)
 336                 return;
 337         if((n = str2addr((cmd & 0x100) ? nc->raddr : nc->laddr, buf)) <= 0)
 338                 return;
 339         if(write(1, buf, n) != n)
 340                 return;
 341
 342         switch(cmd){
 343         default:
 344                 return;
 345         case 0x01:      /* CONNECT */
 346                 break;
 347         case 0x02:      /* BIND */
 348                 cfd = listen(dir, ldir);
 349                 close(fd);
 350                 fd = -1;
 351                 if(cfd >= 0){
 352                         strcpy(dir, ldir);
 353                         fd = accept(cfd, dir);
 354                 }
 355                 cmd |= 0x100;
 356                 goto Reply;
 357         case 0x102:
 358                 break;
 359         case 0x03:      /* UDP */
 360                 if(udprelay(fd, dir) == 0)
 361                         while(read(0, buf, sizeof(buf)) > 0)
 362                                 ;
 363                 goto Hangup;
 364         }
 365
 366         /* relay data */
 367         switch(rfork(RFMEM|RFPROC|RFFDG|RFNOWAIT)){
 368         case -1:
 369                 return;
 370         case 0:
 371                 dup(fd, 0);
 372                 break;
 373         default:
 374                 dup(fd, 1);
 375         }
 376         while((n = read(0, buf, sizeof(buf))) > 0)
 377                 if(write(1, buf, n) != n)
 378                         break;
 379 Hangup:
 380         if(cfd >= 0)
 381                 hangup(cfd);
 382         postnote(PNGROUP, getpid(), "kill");
 383 }
 384