sys/src/cmd/ip/torrent.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <mp.h>
   4 #include <libsec.h>
   5
   6 typedef struct Dict Dict;
   7 typedef struct Piece Piece;
   8 typedef struct File File;
   9 typedef struct Stats Stats;
  10
  11 struct Dict
  12 {
  13         Dict    *val;
  14         Dict    *next;
  15         char    *start, *end;
  16         int     len;
  17         char    typ;    // i, d, s, l
  18         char    str[];
  19 };
  20
  21 struct Piece
  22 {
  23         uchar   *hash;
  24         int     len;
  25         int     brk;
  26 };
  27
  28 struct File
  29 {
  30         File    *next;
  31         char    *name;
  32         int     fd;
  33         vlong   off;
  34         vlong   len;
  35 };
  36
  37 struct Stats
  38 {
  39         Lock;
  40         vlong   up;
  41         vlong   down;
  42         vlong   left;
  43 };
  44
  45 enum {
  46         MAXIO = 16*1024,
  47         SRVPROCS = 16,
  48         CLIPROCS = 16,
  49 };
  50
  51 int debug;
  52 int nproc = 1;
  53 int killgroup = -1;
  54 int port = 6881;
  55 char *deftrack = "http://exodus.desync.com/announce";
  56 char *mntweb = "/mnt/web";
  57 uchar infohash[20];
  58 uchar peerid[20];
  59 int blocksize;
  60
  61 int npieces;
  62 Piece *pieces;
  63
  64 int nhavemap;
  65 uchar *havemap;
  66 int nhavepieces;
  67
  68 File *files;
  69 Stats stats;
  70
  71 int
  72 finished(void)
  73 {
  74         return nhavepieces >= npieces;
  75 }
  76
  77 void
  78 freedict(Dict *d)
  79 {
  80         if(d){
  81                 if(d->val != d)
  82                         freedict(d->val);
  83                 freedict(d->next);
  84                 free(d);
  85         }
  86 }
  87
  88 char*
  89 bparse(char *s, char *e, Dict **dp)
  90 {
  91         char *x, t;
  92         Dict *d;
  93         int n;
  94
  95         *dp = nil;
  96         if(s >= e)
  97                 return e;
  98
  99         t = *s;
 100         switch(t){
 101         case 'd':
 102         case 'l':
 103                 x = s++;
 104                 d = nil;
 105                 while(s < e){
 106                         if(*s == 'e'){
 107                                 s++;
 108                                 break;
 109                         }
 110                         if(t == 'd'){
 111                                 s = bparse(s, e, dp);
 112                                 if((d = *dp) == nil)
 113                                         break;
 114                         } else
 115                                 d = *dp = mallocz(sizeof(*d), 1);
 116                         d->typ = t;
 117                         d->start = x;
 118                         if(s < e){
 119                                 s = bparse(s, e, &d->val);
 120                                 dp = &d->next;
 121                                 d->end = s;
 122                         }
 123                         x = s;
 124                 }
 125                 if(d)
 126                         d->end = s;
 127                 return s;
 128         case 'i':
 129                 x = ++s;
 130                 if((s = memchr(x, 'e', e - x)) == nil)
 131                         return e;
 132                 n = s - x;
 133                 s++;
 134                 break;
 135         default:
 136                 if((x = memchr(s, ':', e - s)) == nil)
 137                         return e;
 138                 x++;
 139                 if((n = atoi(s)) < 0)
 140                         return e;
 141                 s = x + n;
 142                 if((s > e) || (s < x)){
 143                         n = e - x;
 144                         s = e;
 145                 }
 146                 t = 's';
 147         }
 148         d = mallocz(sizeof(*d) + n+1, 1);
 149         d->typ = t;
 150         memmove(d->str, x, d->len = n);
 151         d->str[n] = 0;
 152         *dp = d;
 153         return s;
 154 }
 155
 156 char*
 157 dstr(Dict *d)
 158 {
 159         if(d && (d->typ == 's' || d->typ == 'i'))
 160                 return d->str;
 161         return nil;
 162 }
 163
 164 Dict*
 165 dlook(Dict *d, char *s)
 166 {
 167         for(; d && d->typ == 'd'; d = d->next)
 168                 if(d->len && strcmp(d->str, s) == 0)
 169                         return d->val;
 170         return nil;
 171 }
 172
 173 int
 174 readall(int fd, char **p)
 175 {
 176         int n, r;
 177
 178         n = 0;
 179         *p = nil;
 180         while(*p = realloc(*p, n+1024)){
 181                 if((r = read(fd, *p+n, 1024)) <= 0)
 182                         break;
 183                 n += r;
 184         }
 185         return n;
 186 }
 187
 188 int
 189 rwpiece(int wr, int index, uchar *data, int len, int poff)
 190 {
 191         vlong off;
 192         int n, m;
 193         File *f;
 194
 195         if(len <= 0 || poff >= pieces[index].len)
 196                 return 0;
 197         if(len+poff > pieces[index].len)
 198                 len = pieces[index].len - poff;
 199         off = (vlong)index * blocksize;
 200         off += poff;
 201         for(f = files; f; f = f->next)
 202                 if((f->off+f->len) > off)
 203                         break;
 204         off -= f->off;
 205         n = ((off + len) > f->len) ? f->len - off : len;
 206         if((n = (wr ? pwrite(f->fd, data, n, off) : pread(f->fd, data, n, off))) <= 0)
 207                 return -1;
 208         if((m = rwpiece(wr, index, data + n, len - n, poff + n)) < 0)
 209                 return -1;
 210         return n+m;
 211 }
 212
 213 int
 214 havepiece(int x)
 215 {
 216         uchar *p, m, hash[20];
 217         int n;
 218
 219         m = 0x80>>(x&7);
 220         if(havemap[x>>3] & m)
 221                 return 1;
 222         p = malloc(blocksize);
 223         n = pieces[x].len;
 224         if(rwpiece(0, x, p, n, 0) != n){
 225                 free(p);
 226                 return 0;
 227         }
 228         sha1(p, n, hash, nil);
 229         free(p);
 230         if(memcmp(hash, pieces[x].hash, 20))
 231                 return 0;
 232         lock(&stats);
 233         if((havemap[x>>3] & m) == 0){
 234                 havemap[x>>3] |= m;
 235                 nhavepieces++;
 236                 stats.left -= pieces[x].len;
 237         }
 238         unlock(&stats);
 239         return 1;
 240 }
 241
 242 int
 243 pickpiece(uchar *map)
 244 {
 245         int i, x, r, k;
 246         uchar m;
 247
 248         r = -1;
 249         k = 0;
 250         for(i = 0; i<nhavemap; i++){
 251                 if(map[i] == 0)
 252                         continue;
 253                 for(x = i<<3, m = 0x80; m; m >>= 1, x++){
 254                         if((~map[i] | havemap[i]) & m)
 255                                 continue;
 256                         if(nrand(++k) == 0)
 257                                 r = x;
 258                 }
 259         }
 260         return r;
 261 }
 262
 263 int
 264 unpack(uchar *s, int n, char *fmt, ...)
 265 {
 266         va_list arg;
 267         uchar *b, *e;
 268
 269         b = s;
 270         e = b + n;
 271         va_start(arg, fmt);
 272         for(; *fmt; fmt++) {
 273                 switch(*fmt){
 274                 case '_':
 275                         s++;
 276                         break;
 277                 case 'b':
 278                         if(s+1 > e) goto Err;
 279                         *va_arg(arg, int*) = *s++;
 280                         break;
 281                 case 'w':
 282                         if(s+2 > e) goto Err;
 283                         *va_arg(arg, int*) = s[0]<<8 | s[1];
 284                         s += 2;
 285                         break;
 286                 case 'l':
 287                         if(s+4 > e) goto Err;
 288                         *va_arg(arg, int*) = s[0]<<24 | s[1]<<16 | s[2]<<8 | s[3];
 289                         s += 4;
 290                         break;
 291                 case 'v':
 292                         if(s+4 > e) goto Err;
 293                         *va_arg(arg, vlong*) =
 294                                 (vlong)s[0]<<56 |
 295                                 (vlong)s[1]<<48 |
 296                                 (vlong)s[2]<<40 |
 297                                 (vlong)s[3]<<32 |
 298                                 (vlong)s[4]<<24 |
 299                                 (vlong)s[5]<<16 |
 300                                 (vlong)s[6]<<8 |
 301                                 (vlong)s[7];
 302                         s += 8;
 303                         break;
 304                 }
 305         }
 306         va_end(arg);
 307         return s - b;
 308 Err:
 309         va_end(arg);
 310         return -1;
 311 }
 312
 313 int
 314 pack(uchar *s, int n, char *fmt, ...)
 315 {
 316         va_list arg;
 317         uchar *b, *e;
 318         vlong v;
 319         int i;
 320
 321         b = s;
 322         e = b + n;
 323         va_start(arg, fmt);
 324         for(; *fmt; fmt++) {
 325                 switch(*fmt){
 326                 case '_':
 327                         i = 0;
 328                         if(0){
 329                 case 'b':
 330                         i = va_arg(arg, int);
 331                         }
 332                         if(s+1 > e) goto Err;
 333                         *s++ = i & 0xFF;
 334                         break;
 335                 case 'w':
 336                         i = va_arg(arg, int);
 337                         if(s+2 > e) goto Err;
 338                         *s++ = (i>>8) & 0xFF;
 339                         *s++ = i & 0xFF;
 340                         break;
 341                 case 'l':
 342                         i = va_arg(arg, int);
 343                         if(s+4 > e) goto Err;
 344                         *s++ = (i>>24) & 0xFF;
 345                         *s++ = (i>>16) & 0xFF;
 346                         *s++ = (i>>8) & 0xFF;
 347                         *s++ = i & 0xFF;
 348                         break;
 349                 case 'v':
 350                         v = va_arg(arg, vlong);
 351                         if(s+8 > e) goto Err;
 352                         *s++ = (v>>56) & 0xFF;
 353                         *s++ = (v>>48) & 0xFF;
 354                         *s++ = (v>>40) & 0xFF;
 355                         *s++ = (v>>32) & 0xFF;
 356                         *s++ = (v>>24) & 0xFF;
 357                         *s++ = (v>>16) & 0xFF;
 358                         *s++ = (v>>8) & 0xFF;
 359                         *s++ = v & 0xFF;
 360                         break;
 361                 case '*':
 362                         i = va_arg(arg, int);
 363                         if(s+i > e) goto Err;
 364                         memmove(s, va_arg(arg, void*), i);
 365                         s += i;
 366                         break;
 367                 }
 368         }
 369         va_end(arg);
 370         return s - b;
 371 Err:
 372         va_end(arg);
 373         return -1;
 374 }
 375
 376
 377
 378 int
 379 peer(int fd, int incoming, char *addr)
 380 {
 381         uchar buf[64+MAXIO], *map, *told, *p, m;
 382         int mechoking, hechoking;
 383         int mewant, hewant;
 384         int workpiece;
 385         int i, o, l, x, n;
 386
 387         if(debug) fprint(2, "peer %s: %s connected\n", addr, incoming ? "incoming" : "outgoing");
 388
 389         for(i=0; i<2; i++){
 390                 if((incoming && i) || (!incoming && !i)){
 391                         if(debug) fprint(2, "peer %s: -> handshake\n", addr);
 392                         n = pack(buf, sizeof(buf), "*________**",
 393                                 20, "\x13BitTorrent protocol",
 394                                 sizeof(infohash), infohash,
 395                                 sizeof(peerid), peerid);
 396                         if(write(fd, buf, n) != n)
 397                                 return 1;
 398                 }
 399                 if((incoming && !i) || (!incoming && i)){
 400                         n = 20 + 8 + sizeof(infohash);
 401                         if((n = readn(fd, buf, n)) != n)
 402                                 return 1;
 403                         if(memcmp(buf, "\x13BitTorrent protocol", 20))
 404                                 return 0;
 405                         if(memcmp(infohash, buf + 20 + 8, sizeof(infohash)))
 406                                 return 0;
 407                         if(debug) fprint(2, "peer %s: <- handshake\n", addr);
 408                 }
 409         }
 410         if(readn(fd, buf, sizeof(peerid)) != sizeof(peerid))
 411                 return 1;
 412         if(memcmp(peerid, buf, sizeof(peerid)) == 0)
 413                 return 0;
 414         if(debug) fprint(2, "peer %s: peerid %.*s\n", addr, sizeof(peerid), (char*)buf);
 415
 416         mechoking = 1;
 417         hechoking = 1;
 418         mewant = 0;
 419         hewant = 0;
 420         workpiece = -1;
 421         map = mallocz(nhavemap, 1);
 422         told = malloc(nhavemap);
 423
 424         if(debug) fprint(2, "peer %s: -> bitfield %d\n", addr, nhavemap);
 425         memmove(told, havemap, nhavemap);
 426         n = pack(buf, sizeof(buf), "lb*", nhavemap+1, 0x05, nhavemap, told);
 427         if(write(fd, buf, n) != n)
 428                 goto Out;
 429
 430         for(;;){
 431                 for(i=0; i<nhavemap; i++){
 432                         if(told[i] != havemap[i]){
 433                                 for(x = i<<3, m = 0x80; m; m >>= 1, x++){
 434                                         if((~havemap[i] | told[i] | map[i]) & m)
 435                                                 continue;
 436                                         told[i] |= m;
 437                                         if(debug) fprint(2, "peer %s: -> have %d\n", addr, x);
 438                                         n = pack(buf, sizeof(buf), "lbl", 1+4, 0x04, x);
 439                                         if(write(fd, buf, n) != n)
 440                                                 goto Out;
 441                                 }
 442                         }
 443                         if(!mewant && (map[i] & ~havemap[i])){
 444                                 mewant = 1;
 445                                 if(debug) fprint(2, "peer %s: -> interested\n", addr);
 446                                 n = pack(buf, sizeof(buf), "lb", 1, 0x02);
 447                                 if(write(fd, buf, n) != n)
 448                                         goto Out;
 449                         }
 450                 }
 451                 if(!hechoking && mewant){
 452                         x = workpiece;
 453                         if(x >= 0 && pieces[x].brk < pieces[x].len)
 454                                 {}
 455                         else x = pickpiece(map);
 456                         if(x >= 0){
 457                                 o = pieces[x].brk;
 458                                 l = pieces[x].len - o;
 459                                 if(l > MAXIO)
 460                                         l = MAXIO;
 461                                 if(debug) fprint(2, "peer %s: -> request %d %d %d\n", addr, x, o, l);
 462                                 n = pack(buf, sizeof(buf), "lblll", 1+4+4+4, 0x06, x, o, l);
 463                                 if(write(fd, buf, n) != n)
 464                                         goto Out;
 465                                 workpiece = x;
 466                         }
 467                 }
 468                 if(mechoking && hewant){
 469                         mechoking = 0;
 470                         if(debug) fprint(2, "peer %s: -> unchoke\n", addr);
 471                         n = pack(buf, sizeof(buf), "lb", 1, 0x01);
 472                         if(write(fd, buf, n) != n)
 473                                 goto Out;
 474                 }
 475
 476                 if(readn(fd, buf, 4) != 4)
 477                         break;
 478                 unpack(buf, 4, "l", &n);
 479                 if(n < 0 || n > sizeof(buf))
 480                         break;
 481                 if(n == 0)
 482                         continue;
 483                 if(readn(fd, buf, n) != n)
 484                         break;
 485
 486                 n--;
 487                 p = buf+1;
 488                 switch(*buf){
 489                 case 0x00:      // Choke
 490                         hechoking = 1;
 491                         workpiece = -1;
 492                         if(debug) fprint(2, "peer %s: <- choke\n", addr);
 493                         break;
 494                 case 0x01:      // Unchoke
 495                         hechoking = 0;
 496                         if(debug) fprint(2, "peer %s: <- unchoke\n", addr);
 497                         break;
 498                 case 0x02:      // Interested
 499                         hewant = 1;
 500                         if(debug) fprint(2, "peer %s: <- interested\n", addr);
 501                         break;
 502                 case 0x03:      // Notinterested
 503                         hewant = 0;
 504                         if(debug) fprint(2, "peer %s: <- notinterested\n", addr);
 505                         break;
 506                 case 0x04:      // Have <piceindex>
 507                         if(unpack(p, n, "l", &x) < 0)
 508                                 goto Out;
 509                         if(debug) fprint(2, "peer %s: <- have %d\n", addr, x);
 510                         if(x < 0 || x >= npieces)
 511                                 continue;
 512                         map[x>>3] |= 0x80>>(x&7);
 513                         break;
 514                 case 0x05:      // Bitfield
 515                         if(debug) fprint(2, "peer %s: <- bitfield %d\n", addr, n);
 516                         if(n != nhavemap)
 517                                 continue;
 518                         memmove(map, p, n);
 519                         break;
 520                 case 0x06:      // Request <index> <begin> <length>
 521                         if(unpack(p, n, "lll", &x, &o, &l) < 0)
 522                                 goto Out;
 523                         if(debug) fprint(2, "peer %s: <- request %d %d %d\n", addr, x, o, l);
 524                         if(x < 0 || x >= npieces)
 525                                 continue;
 526                         if(!hewant || mechoking || (~havemap[x>>3]&(0x80>>(x&7))))
 527                                 continue;
 528                         if(debug) fprint(2, "peer %s: -> piece %d %d\n", addr, x, o);
 529                         n = 4+1+4+4;
 530                         if(l > MAXIO)
 531                                 l = MAXIO;
 532                         if((l = rwpiece(0, x, buf + n, l, o)) <= 0)
 533                                 continue;
 534                         n = pack(buf, sizeof(buf), "lbll", 1+4+4+l, 0x07, x, o);
 535                         n += l;
 536                         if(write(fd, buf, n) != n)
 537                                 goto Out;
 538                         lock(&stats);
 539                         stats.up += n;
 540                         unlock(&stats);
 541                         break;
 542                 case 0x07:      // Piece <index> <begin> <block>
 543                         if(unpack(p, n, "ll", &x, &o) != 8)
 544                                 goto Out;
 545                         p += 8;
 546                         n -= 8;
 547                         lock(&stats);
 548                         stats.down += n;
 549                         unlock(&stats);
 550                         if(debug) fprint(2, "peer %s: <- piece %d %d %d\n", addr, x, o, n);
 551                         if(x < 0 || x >= npieces)
 552                                 continue;
 553                         if((pieces[x].brk != o) || (havemap[x>>3]&(0x80>>(x&7))))
 554                                 continue;
 555                         if(rwpiece(1, x, p, n, o) == n){
 556                                 if((pieces[x].brk = o+n) == pieces[x].len){
 557                                         if(!havepiece(x))
 558                                                 pieces[x].brk = 0;
 559                                 }
 560                         }
 561                         break;
 562                 case 0x08:      // Cancel <index> <begin> <length>
 563                         if(unpack(p, n, "lll", &x, &o, &l) < 0)
 564                                 goto Out;
 565                         if(debug) fprint(2, "peer %s: <- cancel %d %d %d\n", addr, x, o, l);
 566                         break;
 567                 case 0x09:      // Port <port>
 568                         if(unpack(p, n, "l", &x) < 0)
 569                                 goto Out;
 570                         if(debug) fprint(2, "peer %s: <- port %d\n", addr, x);
 571                         break;
 572                 }
 573         }
 574
 575 Out:
 576         free(told);
 577         free(map);
 578         return 1;
 579 }
 580
 581 void
 582 server(void)
 583 {
 584         char addr[64], adir[40], ldir[40];
 585         int afd, lfd, dfd, pid, nprocs;
 586         NetConnInfo *ni;
 587
 588         afd = -1;
 589         nprocs = 0;
 590         for(port=6881; port<6890; port++){
 591                 snprint(addr, sizeof(addr), "tcp!*!%d", port);
 592                 if((afd = announce(addr, adir)) >= 0)
 593                         break;
 594         }
 595         if(afd < 0){
 596                 fprint(2, "announce: %r");
 597                 return;
 598         }
 599         if(rfork(RFFDG|RFPROC|RFMEM))
 600                 return;
 601         for(;;){
 602                 if((lfd = listen(adir, ldir)) < 0){
 603                         fprint(2, "listen: %r");
 604                         break;
 605                 }
 606                 while(nprocs >= SRVPROCS)
 607                         if(waitpid() > 0)
 608                                 nprocs--;
 609                 nprocs++;
 610                 if(pid = rfork(RFFDG|RFPROC|RFMEM)){
 611                         if(pid < 0)
 612                                 nprocs--;
 613                         close(lfd);
 614                         continue;
 615                 }
 616                 if((dfd = accept(lfd, ldir)) < 0){
 617                         fprint(2, "accept: %r");
 618                         break;
 619                 }
 620                 ni = getnetconninfo(ldir, dfd);
 621                 peer(dfd, 1, ni ? ni->raddr : "???");
 622                 if(ni) freenetconninfo(ni);
 623                 break;
 624         }
 625         exits(0);
 626 }
 627
 628 void
 629 client(char *ip, char *port)
 630 {
 631         static Dict *peerqh, *peerqt;
 632         static QLock peerslk;
 633         static int nprocs;
 634         char *addr;
 635         Dict *d;
 636         int fd;
 637
 638         if(ip == nil || port == nil)
 639                 return;
 640
 641         d = mallocz(sizeof(*d) + 64, 1);
 642         snprint(addr = d->str, 64, "tcp!%s!%s", ip, port);
 643         qlock(&peerslk);
 644         if(dlook(peerqh, addr)){
 645                 qunlock(&peerslk);
 646                 free(d);
 647                 return;
 648         }
 649         d->len = strlen(addr);
 650         d->typ = 'd';
 651         d->val = d;
 652         /* enqueue to front */
 653         if((d->next = peerqh) == nil)
 654                 peerqt = d;
 655         peerqh = d;
 656         if(nprocs >= CLIPROCS){
 657                 qunlock(&peerslk);
 658                 return;
 659         }
 660         nprocs++;
 661         qunlock(&peerslk);
 662         if(rfork(RFFDG|RFPROC|RFMEM|RFNOWAIT))
 663                 return;
 664
 665         for(;;){
 666                 qlock(&peerslk);
 667                 /* dequeue and put to tail */
 668                 if(d = peerqh){
 669                         if((peerqh = d->next) == nil)
 670                                 peerqt = nil;
 671                         d->next = nil;
 672                         if(peerqt)
 673                                 peerqt->next = d;
 674                         else
 675                                 peerqh = d;
 676                         peerqt = d;
 677                 } else
 678                         nprocs--;
 679                 qunlock(&peerslk);
 680                 if(d == nil)
 681                         exits(0);
 682                 addr = d->str;
 683                 if(debug) fprint(2, "client %s\n", addr);
 684                 if((fd = dial(addr, nil, nil, nil)) >= 0){
 685                         peer(fd, 0, addr);
 686                         close(fd);
 687                 }
 688                 sleep(1000+nrand(5000));
 689         }
 690 }
 691
 692 int
 693 hopen(char *url, ...)
 694 {
 695         int conn, ctlfd, fd, n;
 696         char buf[1024+1];
 697         va_list arg;
 698
 699         snprint(buf, sizeof buf, "%s/clone", mntweb);
 700         if((ctlfd = open(buf, ORDWR)) < 0)
 701                 return -1;
 702         if((n = read(ctlfd, buf, sizeof buf-1)) <= 0){
 703                 close(ctlfd);
 704                 return -1;
 705         }
 706         buf[n] = 0;
 707         conn = atoi(buf);
 708         va_start(arg, url);
 709         strcpy(buf, "url ");
 710         n = 4+vsnprint(buf+4, sizeof(buf)-4, url, arg);
 711         va_end(arg);
 712         if(write(ctlfd, buf, n) != n){
 713         ErrOut:
 714                 close(ctlfd);
 715                 return -1;
 716         }
 717         snprint(buf, sizeof buf, "%s/%d/body", mntweb, conn);
 718         if((fd = open(buf, OREAD)) < 0)
 719                 goto ErrOut;
 720         close(ctlfd);
 721         return fd;
 722 }
 723
 724 void
 725 webseed(Dict *w, File *f)
 726 {
 727         int fd, err, n, m, o, p, x, y;
 728         uchar buf[MAXIO];
 729         vlong off, len;
 730         Dict *w0;
 731         char *s;
 732
 733         if(w == nil || f == nil || finished())
 734                 return;
 735         if(rfork(RFPROC|RFMEM))
 736                 return;
 737         w0 = w;
 738 Retry:
 739         if(debug) fprint(2, "webseed %s %s\n", w->str, f->name);
 740         s = strrchr(w->str, '/');
 741         if(s && s[1] == 0)
 742                 fd = hopen("%s%s", w->str, f->name);
 743         else
 744                 fd = hopen("%s", w->str);
 745         if(fd < 0){
 746 Error:
 747                 if(debug) fprint(2, "webseed %s %s: %r\n", w->str, f->name);
 748                 if(finished())
 749                         exits(0);
 750                 if((w = w->next) == w0)
 751                         exits(0);
 752                 goto Retry;
 753         }
 754
 755         err = 0;
 756         off = f->off;
 757         len = f->len;
 758         while(len > 0 && !finished()){
 759                 m = sizeof(buf);
 760                 if(len < m)
 761                         m = len;
 762                 if((n = read(fd, buf, m)) <= 0)
 763                         break;
 764
 765                 x = off / blocksize;
 766                 p = off - (vlong)x*blocksize;
 767                 off += n;
 768                 len -= n;
 769                 y = off / blocksize;
 770
 771                 o = 0;
 772                 while(n > 0){
 773                         m = pieces[x].len - p;
 774                         if(m > n)
 775                                 m = n;
 776                         if((havemap[x>>3] & (0x80>>(x&7))) == 0)
 777                                 rwpiece(1, x, buf+o, m, p);
 778                         if(x == y)
 779                                 break;
 780                         o += m;
 781                         n -= m;
 782                         p = 0;
 783                         if(havepiece(x++))
 784                                 continue;
 785                         if(++err > 10){
 786                                 close(fd);
 787                                 werrstr("file corrupted");
 788                                 goto Error;
 789                         }
 790                 }
 791         }
 792         havepiece(off / blocksize);
 793         havepiece(f->off / blocksize);
 794         close(fd);
 795         exits(0);
 796 }
 797
 798 void
 799 clients4(uchar *p, int len)
 800 {
 801         char ip[16], port[6];
 802
 803         while(len >= 6){
 804                 len -= 6;
 805                 snprint(ip, sizeof(ip), "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
 806                 snprint(port, sizeof(port), "%d", p[4]<<8 | p[5]);
 807                 p += 6;
 808                 client(ip, port);
 809         }
 810 }
 811
 812 void
 813 webtracker(char *url)
 814 {
 815         char *event, *p;
 816         Dict *d, *l;
 817         int n, fd;
 818
 819         if(rfork(RFPROC|RFMEM))
 820                 return;
 821         if(debug) fprint(2, "webtracker %s\n", url);
 822
 823         event = "&event=started";
 824         for(;;){
 825                 vlong up, down, left;
 826
 827                 lock(&stats);
 828                 up = stats.up;
 829                 down = stats.down;
 830                 left = stats.left;
 831                 unlock(&stats);
 832
 833                 d = nil;
 834                 if((fd = hopen("%s?info_hash=%.*H&peer_id=%.*H&port=%d&"
 835                         "uploaded=%lld&downloaded=%lld&left=%lld&compact=1&no_peer_id=1%s",
 836                         url, sizeof(infohash), infohash, sizeof(peerid), peerid, port,
 837                         up, down, left, event)) >= 0){
 838                         event = "";
 839                         n = readall(fd, &p);
 840                         close(fd);
 841                         bparse(p, p+n, &d);
 842                         free(p);
 843                 } else if(debug) fprint(2, "tracker %s: %r\n", url);
 844                 if(l = dlook(d, "peers")){
 845                         if(l->typ == 's')
 846                                 clients4((uchar*)l->str, l->len);
 847                         else for(; l && l->typ == 'l'; l = l->next)
 848                                 client(dstr(dlook(l->val, "ip")), dstr(dlook(l->val, "port")));
 849                 }
 850                 n = 0;
 851                 if(p = dstr(dlook(d, "interval")))
 852                         n = atoi(p);
 853                 if(n < 10 | n > 60*60)
 854                         n = 2*60;
 855                 freedict(d);
 856                 sleep(n * 1000 + nrand(5000));
 857         }
 858 }
 859
 860 int
 861 udpaddr(char addr[64], int naddr, char *url)
 862 {
 863         int port;
 864         char *x;
 865
 866         if((url = strchr(url, ':')) == nil)
 867                 return -1;
 868         url++;
 869         while(*url == '/')
 870                 url++;
 871         if(x = strchr(url, ':')){
 872                 port = atoi(x+1);
 873         } else {
 874                 port = 80;
 875                 if((x = strchr(url, '/')) == nil)
 876                         x = strchr(url, 0);
 877         }
 878         snprint(addr, naddr, "udp!%.*s!%d", (int)(x-url), url, port);
 879         return 0;
 880 }
 881
 882 void
 883 udptracker(char *url)
 884 {
 885         int fd, event, n, m, a, i;
 886         int transid, interval;
 887         vlong connid;
 888         uchar buf[MAXIO];
 889         char addr[64];
 890
 891         if(udpaddr(addr, sizeof(addr), url) < 0)
 892                 return;
 893         if(rfork(RFPROC|RFMEM))
 894                 return;
 895         if(debug) fprint(2, "udptracker %s\n", addr);
 896
 897         event = 1;
 898         for(;;){
 899                 alarm(30000);
 900                 if((fd = dial(addr, 0, 0, 0)) < 0)
 901                         goto Sleep;
 902
 903                 /* connect */
 904                 transid = rand();
 905                 n = pack(buf, sizeof(buf), "vll", 0x41727101980LL, 0, transid);
 906                 if(write(fd, buf, n) != n)
 907                         goto Sleep;
 908                 for(;;){
 909                         if((n = read(fd, buf, sizeof(buf))) <= 0)
 910                                 goto Sleep;
 911                         if(unpack(buf, n, "llv", &a, &i, &connid) < 0)
 912                                 continue;
 913                         if(a == 0 && i == transid)
 914                                 break;
 915                 }
 916                 alarm(0);
 917
 918                 /* announce */
 919                 transid = rand();
 920                 lock(&stats);
 921                 n = pack(buf, sizeof(buf), "vll**vvvl____llw",
 922                         connid, 1, transid,
 923                         sizeof(infohash), infohash,
 924                         sizeof(peerid), peerid,
 925                         stats.down,
 926                         stats.left,
 927                         stats.up,
 928                         event,
 929                         0, -1,
 930                         port);
 931                 unlock(&stats);
 932
 933                 interval = 0;
 934                 alarm(30000);
 935                 if(write(fd, buf, n) != n)
 936                         goto Sleep;
 937                 for(;;){
 938                         if((n = read(fd, buf, sizeof(buf))) <= 0)
 939                                 goto Sleep;
 940                         if((m = unpack(buf, n, "lll________", &a, &i, &interval)) < 0)
 941                                 continue;
 942                         if(a == 1 && i == transid){
 943                                 clients4(buf+m, n - m);
 944                                 break;
 945                         }
 946                 }
 947                 event = 0;
 948 Sleep:
 949                 alarm(0);
 950                 if(fd >= 0)
 951                         close(fd);
 952                 if(interval < 10 | interval > 60*60)
 953                         interval = 2*60;
 954                 sleep(interval * 1000 + nrand(5000));
 955         }
 956 }
 957
 958 void
 959 tracker(char *url)
 960 {
 961         static Dict *trackers;
 962         static QLock trackerslk;
 963         Dict *d;
 964         int n;
 965
 966         if(url == nil)
 967                 return;
 968         qlock(&trackerslk);
 969         if(dlook(trackers, url)){
 970                 qunlock(&trackerslk);
 971                 return;
 972         }
 973         n = strlen(url);
 974         d = mallocz(sizeof(*d) + n+1, 1);
 975         strcpy(d->str, url);
 976         d->len = n;
 977         d->typ = 'd';
 978         d->val = d;
 979         d->next = trackers;
 980         trackers = d;
 981         url = d->str;
 982         qunlock(&trackerslk);
 983         if(!cistrncmp(url, "udp:", 4))
 984                 udptracker(url);
 985         else
 986                 webtracker(url);
 987 }
 988
 989 int
 990 Hfmt(Fmt *f)
 991 {
 992         uchar *s, *e;
 993         s = va_arg(f->args, uchar*);
 994         if(f->flags & FmtPrec)
 995                 e = s + f->prec;
 996         else
 997                 e = s + strlen((char*)s);
 998         for(; s < e; s++)
 999                 if(fmtprint(f, *s && ((*s >= '0' && *s <= '9') ||
1000                         (*s >= 'a' && *s <= 'z') ||
1001                         (*s >= 'A' && *s <= 'Z') ||
1002                         strchr(".-_~", *s)) ? "%c" : "%%%.2x", *s) < 0)
1003                         return -1;
1004         return 0;
1005 }
1006
1007 int
1008 mktorrent(int fd, Dict *alist, Dict *wlist)
1009 {
1010         uchar *b, h[20];
1011         Dir *d;
1012         int n;
1013
1014         if((d = dirfstat(fd)) == nil)
1015                 return -1;
1016         if(d->qid.type & QTDIR){
1017                 free(d);
1018                 werrstr("file is a directory");
1019                 return -1;
1020         }
1021         if(d->length == 0){
1022                 free(d);
1023                 werrstr("empty file");
1024                 return -1;
1025         }
1026         npieces = 1;
1027         for(blocksize = 256*1024;;blocksize<<=1){
1028                 npieces = (d->length + blocksize-1) / blocksize;
1029                 if(npieces <= 8*1024 || blocksize >= 2*1024*1024)
1030                         break;
1031         }
1032
1033         /*
1034          * keys in dictionaries have to be ordered alphabetically
1035          */
1036         print("d8:announce%ld:%s", strlen(alist->str), alist->str);
1037         if(alist->next){
1038                 print("13:announce-listl");
1039                 print("l%ld:%se", strlen(alist->str), alist->str);
1040                 for(alist = alist->next; alist; alist = alist->next)
1041                         print("l%ld:%se", strlen(alist->str), alist->str);
1042                 print("e");
1043         }
1044
1045         print("4:infod");
1046         print("6:lengthi%llde", d->length);
1047         print("4:name%ld:%s", strlen(d->name), d->name);
1048         print("12:piece lengthi%de", blocksize);
1049         print("6:pieces%d:", npieces*sizeof(h));
1050         free(d);
1051         b = malloc(blocksize);
1052         while((n = readn(fd, b, blocksize)) > 0){
1053                 sha1(b, n, h, nil);
1054                 if(write(1, h, sizeof(h)) != sizeof(h)){
1055                         free(b);
1056                         return -1;
1057                 }
1058                 npieces--;
1059         }
1060         if(npieces){
1061                 werrstr("read failed: %r");
1062                 return -1;
1063         }
1064         free(b);
1065         print("e");
1066
1067         if(wlist){
1068                 if(wlist->next){
1069                         print("8:url-listl");
1070                         for(; wlist; wlist = wlist->next)
1071                                 print("%ld:%s", strlen(wlist->str), wlist->str);
1072                         print("e");
1073                 } else
1074                         print("8:url-list%ld:%s", strlen(wlist->str), wlist->str);
1075         }
1076         print("e");
1077
1078         return 0;
1079 }
1080
1081 int
1082 mkdirs(char *s)
1083 {
1084         char *p;
1085         int f;
1086
1087         if(access(s, AEXIST) == 0)
1088                 return 0;
1089         for(p=strchr(s+1, '/'); p; p=strchr(p+1, '/')){
1090                 *p = 0;
1091                 if(access(s, AEXIST)){
1092                         if((f = create(s, OREAD, DMDIR | 0777)) < 0){
1093                                 *p = '/';
1094                                 return -1;
1095                         }
1096                         close(f);
1097                 }
1098                 *p = '/';
1099         }
1100         return 0;
1101 }
1102
1103 char*
1104 fixnamedup(char *s)
1105 {
1106         int n, l;
1107         char *d;
1108         Rune r;
1109
1110         n = 0;
1111         d = strdup(s);
1112         l = strlen(d);
1113         while(*s){
1114                 s += chartorune(&r, s);
1115                 if(r == ' ')
1116                         r = 0xa0;
1117                 if((n + runelen(r)) >= l){
1118                         l += 64;
1119                         d = realloc(d, l);
1120                 }
1121                 n += runetochar(d + n, &r);
1122         }
1123         d[n] = 0;
1124         return cleanname(d);
1125 }
1126
1127 int
1128 catch(void *, char *msg)
1129 {
1130         if(strstr(msg, "alarm"))
1131                 return 1;
1132         postnote(PNGROUP, killgroup, "kill");
1133         return 0;
1134 }
1135
1136 void
1137 usage(void)
1138 {
1139         fprint(2, "usage: %s [ -vsdpc ] [ -m mtpt ] [ -t tracker-url ] "
1140                   "[ -w webseed-url ] [ file ]\n", argv0);
1141         exits("usage");
1142 }
1143
1144 Dict*
1145 scons(char *s, Dict *t)
1146 {
1147         Dict *l;
1148
1149         if(s == nil)
1150                 return t;
1151         for(l = t; l; l = l->next)
1152                 if(strcmp(l->str, s) == 0)
1153                         return t;
1154         l = mallocz(sizeof(*l) + strlen(s)+1, 1);
1155         l->next = t;
1156         strcpy(l->str, s);
1157         return l;
1158 }
1159
1160 void
1161 main(int argc, char *argv[])
1162 {
1163         int sflag, pflag, vflag, cflag, fd, i, n;
1164         Dict *alist, *wlist, *info, *torrent, *d, *l;
1165         char *p, *s, *e;
1166         File **fp, *f;
1167         vlong len;
1168
1169         fmtinstall('H', Hfmt);
1170         alist = wlist = nil;
1171         sflag = pflag = vflag = cflag = 0;
1172         ARGBEGIN {
1173         case 'm':
1174                 mntweb = EARGF(usage());
1175                 break;
1176         case 't':
1177                 alist = scons(EARGF(usage()), alist);
1178                 break;
1179         case 'w':
1180                 wlist = scons(EARGF(usage()), wlist);
1181                 break;
1182         case 's':
1183                 sflag = 1;
1184                 break;
1185         case 'p':
1186                 pflag = 1;
1187                 break;
1188         case 'v':
1189                 vflag = 1;
1190                 break;
1191         case 'c':
1192                 cflag = 1;
1193                 break;
1194         case 'd':
1195                 debug++;
1196                 break;
1197         default:
1198                 usage();
1199         } ARGEND;
1200
1201         if((s = getenv("NPROC")) != 0){
1202                 if((nproc = atoi(s)) <= 0)
1203                         nproc = 1;
1204                 free(s);
1205         }
1206
1207         fd = 0;
1208         if(*argv)
1209                 if((fd = open(*argv, OREAD)) < 0)
1210                         sysfatal("open: %r");
1211         if(cflag){
1212                 if(alist == nil)
1213                         alist = scons(deftrack, alist);
1214                 if(mktorrent(fd, alist, wlist) < 0)
1215                         sysfatal("%r");
1216                 exits(0);
1217         }
1218         if((n = readall(fd, &p)) <= 0)
1219                 sysfatal("read torrent: %r");
1220         bparse(p, p+n, &torrent);
1221
1222         alist = scons(dstr(dlook(torrent, "announce")), alist);
1223         for(d = dlook(torrent, "announce-list"); d && d->typ == 'l'; d = d->next)
1224                 for(l = d->val; l && l->typ == 'l'; l = l->next)
1225                         alist = scons(dstr(l->val), alist);
1226
1227         if(d = dlook(torrent, "url-list")){
1228                 if(d->typ == 's')
1229                         wlist = scons(dstr(d->val), wlist);
1230                 else for(l = d; l && l->typ == 'l'; l = l->next)
1231                         wlist = scons(dstr(l->val), wlist);
1232                 /* make wlist into a ring */
1233                 for(l = wlist; l && l->next; l = l->next)
1234                         ;
1235                 if(l) l->next = wlist;
1236         }
1237
1238         if(alist == nil && wlist == nil)
1239                 sysfatal("no trackers or webseeds in torrent");
1240
1241         if((d = info = dlook(torrent, "info")) == nil)
1242                 sysfatal("no meta info in torrent");
1243         for(s = e = d->start; d && d->typ == 'd'; d = d->next)
1244                 e = d->end;
1245         sha1((uchar*)s, e - s, (uchar*)infohash, nil);
1246         free(p);
1247
1248         fp = &files;
1249         if(d = dlook(info, "files")){
1250                 for(; d && d->typ == 'l'; d = d->next){
1251                         Dict *di;
1252
1253                         if((s = dstr(dlook(d->val, "length"))) == nil)
1254                                 continue;
1255                         f = mallocz(sizeof(*f), 1);
1256                         f->len = atoll(s);
1257                         f->name = dstr(dlook(info, "name"));
1258                         for(di = dlook(d->val, "path"); di && di->typ == 'l'; di = di->next)
1259                                 if(s = dstr(di->val))
1260                                         f->name = f->name ? smprint("%s/%s", f->name, s) : s;
1261                         *fp = f;
1262                         fp = &f->next;
1263                 }
1264         } else if(s = dstr(dlook(info, "length"))){
1265                 f = mallocz(sizeof(*f), 1);
1266                 f->len = atoll(s);
1267                 f->name = dstr(dlook(info, "name"));
1268                 *fp = f;
1269         }
1270         len = 0;
1271         for(f = files; f; f = f->next){
1272                 if(f->name == nil || f->len <= 0)
1273                         sysfatal("bogus file entry in meta info");
1274                 s = fixnamedup(f->name);
1275                 if(vflag) fprint(pflag ? 2 : 1, "%s\n", s);
1276                 if((f->fd = open(s, ORDWR)) < 0){
1277                         if(mkdirs(s) < 0)
1278                                 sysfatal("mkdirs: %r");
1279                         if((f->fd = create(s, ORDWR, 0666)) < 0)
1280                                 sysfatal("create: %r");
1281                 }
1282                 f->off = len;
1283                 len += f->len;
1284         }
1285         if(len <= 0)
1286                 sysfatal("no files in torrent");
1287
1288         if((s = dstr(dlook(info, "piece length"))) == nil)
1289                 sysfatal("missing piece length in meta info");
1290         if((blocksize = atoi(s)) <= 0)
1291                 sysfatal("bogus piece length in meta info");
1292         d = dlook(info, "pieces");
1293         if(d == nil || d->typ != 's' || d->len <= 0 || d->len % 20)
1294                 sysfatal("bad or no pices in meta info");
1295         npieces = d->len / 20;
1296         pieces = mallocz(sizeof(Piece) * npieces, 1);
1297         nhavemap = (npieces+7) / 8;
1298         havemap = mallocz(nhavemap, 1);
1299         for(i = 0; i<npieces; i++){
1300                 pieces[i].hash = (uchar*)d->str + i*20;
1301                 if(len < blocksize)
1302                         pieces[i].len = len;
1303                 else
1304                         pieces[i].len = blocksize;
1305                 len -= pieces[i].len;
1306                 stats.left += pieces[i].len;
1307         }
1308         if(len)
1309                 sysfatal("pieces do not match file length");
1310
1311         for(i=0; i<nproc; i++){
1312                 switch(rfork(RFPROC|RFMEM)){
1313                 case -1:
1314                         sysfatal("fork: %r");
1315                 case 0:
1316                         for(; i<npieces; i+=nproc)
1317                                 havepiece(i);
1318                         exits(0);
1319                 }
1320         }
1321         while(waitpid() >= 0)
1322                 ;
1323
1324         srand(time(0));
1325         atnotify(catch, 1);
1326         switch(i = rfork(RFPROC|RFMEM|RFNOTEG)){
1327         case -1:
1328                 sysfatal("fork: %r");
1329         case 0:
1330                 memmove(peerid, "-NF9001-", 8);
1331                 for(i=8; i<sizeof(peerid); i++)
1332                         peerid[i] = nrand(10)+'0';
1333                 server();
1334                 for(; alist; alist = alist->next)
1335                         tracker(alist->str);
1336                 for(f = files, l = wlist; f && l; f = f->next, l = l->next)
1337                         webseed(l, f);
1338                 while(waitpid() != -1)
1339                         ;
1340                 break;
1341         default:
1342                 killgroup = i;
1343                 do {
1344                         sleep(1000);
1345                         if(pflag)
1346                                 print("%d %d\n", nhavepieces, npieces);
1347                 } while(!finished() || sflag);
1348         }
1349         postnote(PNGROUP, killgroup, "kill");
1350         exits(0);
1351 }