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         if((fd = accept(cfd, ldir)) < 0)
 116                 return -1;
 117
 118         switch(rfork(RFMEM|RFPROC|RFNOWAIT)){
 119         case -1:
 120                 return -1;
 121         case 0:
 122                 while((r = read(fd, msg.data, sizeof(msg.data))) > 0){
 123                         if(r < 4)
 124                                 continue;
 125                         p = msg.data;
 126                         if(p[0] | p[1] | p[2])
 127                                 continue;
 128                         p += 3;
 129                         switch(*p++){
 130                         default:
 131                                 continue;
 132                         case 0x01:
 133                                 r -= 2+1+1+4+2;
 134                                 if(r < 0)
 135                                         continue;
 136                                 v4tov6(msg.raddr, p);
 137                                 p += 4;
 138                                 break;
 139                         case 0x04:
 140                                 r -= 2+1+1+16+2;
 141                                 if(r < 0)
 142                                         continue;
 143                                 memmove(msg.raddr, p, 16);
 144                                 p += 16;
 145                                 break;
 146                         }
 147                         memmove(msg.rport, p, 2);
 148                         p += 2;
 149                         memmove(msg.data, p, r);
 150                         write(rfd, &msg, sizeof(Udphdr)+r);
 151                 }
 152                 break;
 153         default:
 154                 while((r = read(rfd, &msg, sizeof(msg))) > 0){
 155                         r -= sizeof(Udphdr);
 156                         if(r < 0)
 157                                 continue;
 158                         p = msg.data;
 159                         if(isv4(msg.raddr))
 160                                 n = 2+1+1+4+2;
 161                         else
 162                                 n = 2+1+1+16+2;
 163                         if(r+n > sizeof(msg.data))
 164                                 r = sizeof(msg.data)-n;
 165                         memmove(p+n, p, r);
 166                         *p++ = 0;
 167                         *p++ = 0;
 168                         *p++ = 0;
 169                         if(isv4(msg.raddr)){
 170                                 *p++ = 0x01;
 171                                 v6tov4(p, msg.raddr);
 172                                 p += 4;
 173                         } else {
 174                                 *p++ = 0x04;
 175                                 memmove(p, msg.raddr, 16);
 176                                 p += 16;
 177                         }
 178                         memmove(p, msg.rport, 2);
 179                         r += n;
 180                         write(fd, msg.data, r);
 181                 }
 182         }
 183         return -1;
 184 }
 185
 186 int
 187 sockerr(int err)
 188 {
 189         /* general error */
 190         if(socksver == 4)
 191                 return err ? 0x5b : 0x5a;
 192         else
 193                 return err != 0;
 194 }
 195
 196 void
 197 main(int argc, char *argv[])
 198 {
 199         uchar buf[8*1024], *p;
 200         char addr[128], dir[40], ldir[40], *s;
 201         int cmd, fd, cfd, n;
 202         NetConnInfo *nc;
 203
 204         fmtinstall('I', eipfmt);
 205
 206         setnetmtpt(inside, sizeof(inside), 0);
 207         setnetmtpt(outside, sizeof(outside), 0);
 208         ARGBEGIN {
 209         case 'x':
 210                 setnetmtpt(inside, sizeof(inside), ARGF());
 211                 break;
 212         case 'o':
 213                 setnetmtpt(outside, sizeof(outside), ARGF());
 214                 break;
 215         } ARGEND;
 216
 217         /* ver+cmd or ver+nmethod */
 218         if(readn(0, buf, 2) != 2)
 219                 return;
 220         socksver = buf[0];
 221         if(socksver < 4)
 222                 return;
 223         if(socksver > 5)
 224                 socksver = 5;
 225
 226         if(socksver == 4){
 227                 /* port+ip4 */
 228                 if(readn(0, buf+2, 2+4) != 2+4)
 229                         return;
 230                 /* +user\0 */
 231                 for(p = buf+2+2+4;; p++){
 232                         if(p >= buf+sizeof(buf))
 233                                 return;
 234                         if(read(0, p, 1) != 1)
 235                                 return;
 236                         if(*p == 0)
 237                                 break;
 238                 }
 239                 /* socks 4a dom hack */
 240                 if((buf[4] | buf[5] | buf[6]) == 0 && buf[7]){
 241                         /* +dom\0 */
 242                         for(++p;; p++){
 243                                 if(p >= buf+sizeof(buf))
 244                                         return;
 245                                 if(read(0, p, 1) != 1)
 246                                         return;
 247                                 if(*p == 0)
 248                                         break;
 249                         }
 250                 }
 251         } else {
 252                 /* nmethod */
 253                 if((n = buf[1]) > 0)
 254                         if(readn(0, buf+2, n) != n)
 255                                 return;
 256
 257                 /* ver+method */
 258                 buf[0] = socksver;
 259                 buf[1] = 0x00;  /* no authentication required */
 260                 if(write(1, buf, 2) != 2)
 261                         return;
 262
 263                 /* ver+cmd+res+atyp */
 264                 if(readn(0, buf, 4) != 4)
 265                         return;
 266                 switch(buf[3]){
 267                 default:
 268                         return;
 269                 case 0x01:      /* +ipv4 */
 270                         if(readn(0, buf+4, 4+2) != 4+2)
 271                                 return;
 272                         break;
 273                 case 0x03:      /* +len+dom[len] */
 274                         if(readn(0, buf+4, 1) != 1)
 275                                 return;
 276                         if((n = buf[4]) == 0)
 277                                 return;
 278                         if(readn(0, buf+5, n+2) != n+2)
 279                                 return;
 280                         break;
 281                 case 0x04:      /* +ipv6 */
 282                         if(readn(0, buf+4, 16+2) != 16+2)
 283                                 return;
 284                         break;
 285                 }
 286         }
 287
 288         dir[0] = 0;
 289         fd = cfd = -1;
 290         cmd = buf[1];
 291         switch(cmd){
 292         case 0x01:      /* CONNECT */
 293                 snprint(addr, sizeof(addr), "%s/tcp", outside);
 294                 if((s = addr2str(addr, buf)) == nil)
 295                         break;
 296                 alarm(30000);
 297                 fd = dial(s, 0, dir, &cfd);
 298                 alarm(0);
 299                 break;
 300         case 0x02:      /* BIND */
 301                 if(myipaddr(buf, outside) < 0)
 302                         break;
 303                 snprint(addr, sizeof(addr), "%s/tcp!%I!0", outside, buf);
 304                 fd = announce(addr, dir);
 305                 break;
 306         case 0x03:      /* UDP */
 307                 if(myipaddr(buf, inside) < 0)
 308                         break;
 309                 snprint(addr, sizeof(addr), "%s/udp!%I!0", inside, buf);
 310                 fd = announce(addr, dir);
 311                 break;
 312         }
 313
 314 Reply:
 315         /* reply */
 316         buf[1] = sockerr(fd < 0);                       /* status */
 317         if(socksver == 4){
 318                 buf[0] = 0x00;                          /* vc */
 319                 if(fd < 0){
 320                         memset(buf+2, 0, 2+4);
 321                         write(1, buf, 2+2+4);
 322                         return;
 323                 }
 324         } else {
 325                 buf[0] = socksver;                      /* ver */
 326                 buf[2] = 0x00;                          /* res */
 327                 if(fd < 0){
 328                         buf[3] = 0x01;                  /* atyp */
 329                         memset(buf+4, 0, 4+2);
 330                         write(1, buf, 4+4+2);
 331                         return;
 332                 }
 333         }
 334         if((nc = getnetconninfo(dir, cfd)) == nil)
 335                 return;
 336         if((n = str2addr((cmd & 0x100) ? nc->raddr : nc->laddr, buf)) <= 0)
 337                 return;
 338         if(write(1, buf, n) != n)
 339                 return;
 340
 341         switch(cmd){
 342         default:
 343                 return;
 344         case 0x01:      /* CONNECT */
 345                 break;
 346         case 0x02:      /* BIND */
 347                 cfd = listen(dir, ldir);
 348                 close(fd);
 349                 fd = -1;
 350                 if(cfd >= 0){
 351                         strcpy(dir, ldir);
 352                         fd = accept(cfd, dir);
 353                 }
 354                 cmd |= 0x100;
 355                 goto Reply;
 356         case 0x102:
 357                 break;
 358         case 0x03:      /* UDP */
 359                 if(udprelay(fd, dir) == 0)
 360                         while(read(0, buf, sizeof(buf)) > 0)
 361                                 ;
 362                 goto Hangup;
 363         }
 364
 365         /* relay data */
 366         switch(rfork(RFMEM|RFPROC|RFFDG|RFNOWAIT)){
 367         case -1:
 368                 return;
 369         case 0:
 370                 dup(fd, 0);
 371                 break;
 372         default:
 373                 dup(fd, 1);
 374         }
 375         while((n = read(0, buf, sizeof(buf))) > 0)
 376                 if(write(1, buf, n) != n)
 377                         break;
 378 Hangup:
 379         if(cfd >= 0)
 380                 hangup(cfd);
 381         postnote(PNGROUP, getpid(), "kill");
 382 }
 383