mdw@git.distorted.org.uk Git - fwd/blob - socket.c

   1 /* -*-c-*-
   2  *
   3  * Socket source and target definitions
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the `fwd' port forwarder.
  11  *
  12  * `fwd' is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * `fwd' is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with `fwd'; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 #include "fwd.h"
  28
  29 /*----- Data structures ---------------------------------------------------*/
  30
  31 /* --- Socket source options --- */
  32
  33 typedef struct ssource_opts {
  34   unsigned opt;
  35   unsigned conn;
  36   unsigned listen;
  37   unsigned naccept;
  38 } ssource_opts;
  39
  40 static ssource_opts ssgo = { 256, 0, 5, 1 };
  41
  42 #define SOCKOPT_LIMIT 0u
  43 #define SOCKOPT_NOLIMIT 1u
  44 #define SOCKOPT_ONESHOT 2u
  45
  46 /* --- Socket source --- */
  47
  48 typedef struct ssource {
  49   source s;
  50   addr *a;
  51   target *t;
  52   addr_opts *ao;
  53   ssource_opts o;
  54   sel_file r;
  55 } ssource;
  56
  57 /* --- Socket target --- */
  58
  59 typedef struct starget {
  60   target t;
  61   addr *a;
  62   addr_opts *ao;
  63 } starget;
  64
  65 /* --- Socket target endpoint --- */
  66
  67 typedef struct stept {
  68   endpt e;
  69   conn c;
  70   char *desc;
  71 } stept;
  72
  73 /* --- Socket source endpoint --- */
  74
  75 typedef struct ssept {
  76   endpt e;
  77   ssource *s;
  78 } ssept;
  79
  80 /*----- Protocol table ----------------------------------------------------*/
  81
  82 static addr_ops *addrs[] = { &inet_ops, &un_ops, 0 };
  83
  84 /*----- Other persistent variables ----------------------------------------*/
  85
  86 static addr_opts gsao = { 0 }, gtao = { 0 };
  87
  88 /*----- Parsing address types ---------------------------------------------*/
  89
  90 /* --- @getaddrtype@ --- *
  91  *
  92  * Arguments:   @scanner *sc@ = pointer to scanner (for error reporting)
  93  *              @const char *p@ = pointer to protocol name
  94  *              @int abbrev@ = nonzero to allow abbreviations
  95  *
  96  * Returns:     Pointer to address operations table or null.
  97  *
  98  * Use:         Looks up a protocol name.  Handy when parsing addresses and
  99  *              other bits of configuration.  Returns null if no matching
 100  *              address was found.
 101  */
 102
 103 static addr_ops *getaddrtype(scanner *sc, const char *p, int abbrev)
 104 {
 105   addr_ops **ops;
 106   addr_ops *chosen = 0;
 107   size_t sz = strlen(p);
 108
 109   for (ops = addrs; *ops; ops++) {
 110     if (strncmp((*ops)->name, p, sz) == 0) {
 111       if ((*ops)->name[sz] == 0)
 112         return (*ops);
 113       else if (chosen && abbrev)
 114         error(sc, "ambiguous socket address type `%s'", p);
 115       chosen = *ops;
 116     }
 117   }
 118   if (!abbrev)
 119     return (0);
 120   return (chosen);
 121 }
 122
 123 /* --- @getaddr@ --- *
 124  *
 125  * Arguments:   @scanner *sc@ = pointer to scanner to read from
 126  *              @unsigned type@ = address type (@ADDR_SRC@ or @ADDR_DEST@)
 127  *
 128  * Returns:     Pointer to an address successfully read.
 129  *
 130  * Use:         Reads an optionally qualified address.
 131  */
 132
 133 static addr *getaddr(scanner *sc, unsigned type)
 134 {
 135   addr_ops *ops = 0;
 136   int abbrev = 0;
 137
 138   if (sc->t == ':') {
 139     token(sc);
 140     abbrev = 1;
 141   }
 142   if (sc->t == CTOK_WORD)
 143     ops = getaddrtype(sc, sc->d.buf, abbrev);
 144   if (ops)
 145     token(sc);
 146   else if (abbrev)
 147     error(sc, "unknown socket address type `%s'", sc->d.buf);
 148   else
 149     ops = &inet_ops;
 150   if (sc->t == ':')
 151     token(sc);
 152
 153   return (ops->read(sc, type));
 154 }
 155
 156 /*----- Socket endpoints --------------------------------------------------*/
 157
 158 /* --- @wclose@ --- */
 159
 160 static void sept_wclose(endpt *e)
 161 {
 162   shutdown(e->out->fd, 1);
 163 }
 164
 165 /* --- @close@ (source) --- */
 166
 167 static void ss_listen(ssource */*ss*/);
 168
 169 static void ssept_close(endpt *e)
 170 {
 171   ssept *ee = (ssept *)e;
 172
 173   if (ee->s->o.opt == SOCKOPT_LIMIT) {
 174     ee->s->o.conn++;
 175     if (ee->s->o.conn == 1)
 176       ss_listen(ee->s);
 177   }
 178   REFFD_DEC(ee->e.in);
 179   REFFD_DEC(ee->e.out);
 180   fw_dec();
 181   DESTROY(ee);
 182 }
 183
 184 /* --- @close@ (target) --- */
 185
 186 static void stept_close(endpt *e)
 187 {
 188   stept *ee = (stept *)e;
 189
 190   if (ee->e.f & EPF_PENDING)
 191     conn_kill(&ee->c);
 192   else {
 193     REFFD_DEC(ee->e.in);
 194     REFFD_DEC(ee->e.out);
 195   }
 196
 197   xfree(ee->desc);
 198   fw_dec();
 199   DESTROY(ee);
 200 }
 201
 202 /* --- @starget_connected@ --- *
 203  *
 204  * Arguments:   @int fd@ = file descriptor now ready for use
 205  *              @void *p@ = pointer to an endpoint structure
 206  *
 207  * Returns:     ---
 208  *
 209  * Use:         Handles successful connection of the target endpoint.
 210  */
 211
 212 void starget_connected(int fd, void *p)
 213 {
 214   stept *e = p;
 215
 216   if (fd == -1) {
 217     fw_log(-1, "[%s] connection failed: %s", e->desc, strerror(errno));
 218     endpt_kill(&e->e);
 219   } else {
 220     reffd *r = reffd_init(fd);
 221     int opt = 1;
 222     REFFD_INC(r);
 223     fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 224     setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 225     e->e.in = e->e.out = r;
 226     e->e.f &= ~EPF_PENDING;
 227     if (e->e.other)
 228       endpt_join(&e->e, e->e.other, 0);
 229   }
 230 }
 231
 232 /* --- Socket endpoint definition --- */
 233
 234 static endpt_ops ssept_ops = {
 235   0, 0, sept_wclose, ssept_close
 236 };
 237
 238 static endpt_ops stept_ops = {
 239   0, 0, sept_wclose, stept_close
 240 };
 241
 242 /*----- Source definition -------------------------------------------------*/
 243
 244 /* --- @option@ --- */
 245
 246 static int ssource_option(source *s, scanner *sc)
 247 {
 248   ssource *ss = (ssource *)s;
 249   ssource_opts *sso = ss ? &ss->o : &ssgo;
 250
 251   CONF_BEGIN(sc, "socket", "socket source")
 252
 253   /* --- Make sure the next token is a word --- */
 254
 255   if (sc->t != CTOK_WORD)
 256     error(sc, "parse error, option keyword expected");
 257
 258   /* --- Handle options at this level --- */
 259
 260   if (strcmp(sc->d.buf, "conn") == 0) {
 261     token(sc);
 262     if (sc->t == '=')
 263       token(sc);
 264     if (sc->t != CTOK_WORD)
 265       error(sc, "parse error, expected `unlimited', `one-shot' or number");
 266     if (isdigit((unsigned char)sc->d.buf[0])) {
 267       sso->conn = atoi(sc->d.buf);
 268       if (sso->conn == 0)
 269         error(sc, "argument of `conn' must be positive");
 270       sso->opt = SOCKOPT_LIMIT;
 271       token(sc);
 272     } else {
 273       sso->conn = 0;
 274       sso->opt = 1 + (1 & conf_enum(sc,
 275                                     "unlimited,one-shot,infinite",
 276                                     ENUM_ABBREV, "`conn' option"));
 277     }
 278     CONF_ACCEPT;
 279   }
 280
 281   if (strcmp(sc->d.buf, "listen") == 0) {
 282     token(sc);
 283     if (sc->t == '=')
 284       token(sc);
 285     if (sc->t != CTOK_WORD || !isdigit((unsigned char)sc->d.buf[0]))
 286       error(sc, "parse error, expected number");
 287     sso->listen = atoi(sc->d.buf);
 288     if (sso->listen == 0)
 289       error(sc, "argument of `listen' must be positive");
 290     token(sc);
 291     CONF_ACCEPT;
 292   }
 293
 294   if (strcmp(sc->d.buf, "accept") == 0 ||
 295       strcmp(sc->d.buf, "accept-count") == 0) {
 296     token(sc);
 297     if (sc->t == '=')
 298       token(sc);
 299     if (sc->t != CTOK_WORD)
 300       error(sc, "parse error, expected `unlimited' or number");
 301     else if (isdigit((unsigned char)sc->d.buf[0])) {
 302       sso->naccept = atoi(sc->d.buf);
 303       if (sso->naccept == 0)
 304         error(sc, "argument of `accept-count' must be positive");
 305     } else {
 306       sso->naccept = 0;
 307       conf_enum(sc, "unlimited,infinite",
 308                 ENUM_ABBREV, "`accept-count' option");
 309     }
 310     token(sc);
 311     CONF_ACCEPT;
 312   }
 313
 314   if (strcmp(sc->d.buf, "logging") == 0 ||
 315       strcmp(sc->d.buf, "log") == 0) {
 316     addr_opts *ao = ss ? ss->ao : &gsao;
 317     token(sc);
 318     if (sc->t == '=')
 319       token(sc);
 320     if (conf_enum(sc, "no,yes", ENUM_ABBREV, "logging status"))
 321       ao->f &= ~ADDRF_NOLOG;
 322     else
 323       ao->f |= ADDRF_NOLOG;
 324     CONF_ACCEPT;
 325   }
 326
 327   /* --- Pass the option around the various address types --- */
 328
 329   if (ss) {
 330     if (ss->a->ops->option && ss->a->ops->option(sc, ss->ao, ADDR_SRC))
 331       CONF_ACCEPT;
 332   } else {
 333     addr_ops **a;
 334     for (a = addrs; *a; a++) {
 335       if ((*a)->option && (*a)->option(sc, 0, ADDR_GLOBAL))
 336         CONF_ACCEPT;
 337     }
 338   }
 339
 340   /* --- Nobody understood the option --- */
 341
 342   CONF_END;
 343 }
 344
 345 /* --- @read@ --- */
 346
 347 static source *ssource_read(scanner *sc)
 348 {
 349   ssource *ss;
 350
 351   (void)(conf_prefix(sc, "socket") || conf_prefix(sc, "sk"));
 352   ss = CREATE(ssource);
 353   ss->s.ops = &ssource_ops;
 354   ss->s.desc = 0;
 355   ss->t = 0;
 356   ss->a = getaddr(sc, ADDR_SRC);
 357   if (ss->a->ops->initsrcopts)
 358     ss->ao = ss->a->ops->initsrcopts();
 359   else
 360     ss->ao = CREATE(addr_opts);
 361   *ss->ao = gsao;
 362   ss->o = ssgo;
 363   return (&ss->s);
 364 }
 365
 366 /* --- @ss_accept@ --- *
 367  *
 368  * Arguments:   @int fd@ = file descriptor to accept from
 369  *              @unsigned mode@ = what's ready with the descriptor
 370  *              @void *p@ = pointer to the source definition
 371  *
 372  * Returns:     ---
 373  *
 374  * Use:         Accepts an incoming connection and attaches it to a target
 375  *              endpoint.
 376  */
 377
 378 static void ssource_destroy(source */*s*/);
 379
 380 static void ss_accept(int fd, unsigned mode, void *p)
 381 {
 382   ssource *ss = p;
 383   ssept *e;
 384   endpt *ee;
 385   reffd *r;
 386   int acceptp = 1;
 387   unsigned i = 0;
 388
 389   while (acceptp) {
 390
 391     /* --- Make the file descriptor --- */
 392
 393     {
 394       int opt = 1;
 395       if ((r = ss->a->ops->accept(fd, ss->ao, ss->s.desc)) == 0)
 396         return;
 397       setsockopt(r->fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 398       fdflags(r->fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 399     }
 400
 401     /* --- Make an endpoint --- */
 402
 403     e = CREATE(ssept);
 404     e->e.ops = &ssept_ops;
 405     e->e.other = 0;
 406     e->e.f = EPF_FILE;
 407     e->e.t = 0;
 408     e->e.in = e->e.out = r;
 409     e->s = ss;
 410     REFFD_INC(r);
 411
 412     /* --- Obtain the target endpoint and let rip --- */
 413
 414     if ((ee = ss->t->ops->create(ss->t, ss->s.desc)) == 0) {
 415       REFFD_DEC(r);
 416       REFFD_DEC(r);
 417       DESTROY(e);
 418       return;
 419     }
 420     fw_inc();
 421
 422     /* --- Note that we've done one --- */
 423
 424     i++;
 425     if (i >= ss->o.naccept)
 426       acceptp = 0;
 427
 428     /* --- Remove the listening socket if necessary --- */
 429
 430     switch (ss->o.opt) {
 431       case SOCKOPT_LIMIT:
 432         ss->o.conn--;
 433         if (!ss->o.conn) {
 434           if (!(ss->ao->f & ADDRF_NOLOG))
 435             fw_log(-1, "[%s] maximum connections reached", ss->s.desc);
 436           sel_rmfile(&ss->r);
 437           close(ss->r.fd);
 438           if (ss->a->ops->unbind)
 439             ss->a->ops->unbind(ss->a);
 440           acceptp = 0;
 441         }
 442         break;
 443       case SOCKOPT_NOLIMIT:
 444         break;
 445       case SOCKOPT_ONESHOT:
 446         sel_rmfile(&ss->r);
 447         close(ss->r.fd);
 448         if (ss->a->ops->unbind)
 449           ss->a->ops->unbind(ss->a);
 450         ssource_destroy(&ss->s);
 451         acceptp = 0;
 452         break;
 453     }
 454
 455     /* --- Let everything else happen --- */
 456
 457     endpt_join(&e->e, ee, ss->s.desc);
 458   }
 459 }
 460
 461 /* --- @ss_listen@ --- *
 462  *
 463  * Arguments:   @ssource *ss@ = source to listen on
 464  *
 465  * Returns:     ---
 466  *
 467  * Use:         Sets the socket to listen again, if it stopped for some
 468  *              reason.  This is a copy of the code in the @read@ function,
 469  *              because it has different (wildly different) error handling
 470  *              behaviour.
 471  */
 472
 473 static void ss_listen(ssource *ss)
 474 {
 475   int fd;
 476   int opt = 1;
 477
 478   if (!(ss->ao->f & ADDRF_NOLOG))
 479     fw_log(-1, "[%s] reattaching listener", ss->s.desc);
 480
 481   /* --- Make the socket --- */
 482
 483   if ((fd = ss->a->ops->bind(ss->a, ss->ao)) < 0) {
 484     fw_log(-1, "[%s] couldn't create socket: %s",
 485            ss->s.desc, strerror(errno));
 486     goto fail_0;
 487   }
 488
 489   /* --- Set it to listen for connections --- */
 490
 491   setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 492   fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 493   if (listen(fd, ss->o.listen)) {
 494     fw_log(-1, "[%s] couldn't listen on socket: %s",
 495            ss->s.desc, strerror(errno));
 496     goto fail_1;
 497   }
 498
 499   /* --- Set the listener up again --- */
 500
 501   ss->r.fd = fd;
 502   sel_addfile(&ss->r);
 503   return;
 504
 505   /* --- Tidy up if it failed --- *
 506    *
 507    * I'll just remove the entire source.
 508    */
 509
 510 fail_1:
 511   close(fd);
 512 fail_0:
 513   ss->o.conn = 0;
 514   ssource_destroy(&ss->s);
 515 }
 516
 517 /* --- @attach@ --- */
 518
 519 static void ssource_attach(source *s, scanner *sc, target *t)
 520 {
 521   ssource *ss = (ssource *)s;
 522   int fd;
 523   int opt = 1;
 524
 525   ss->t = t;
 526
 527   /* --- Initialize the description string --- */
 528
 529   {
 530     dstr d = DSTR_INIT;
 531     dstr_puts(&d, "socket.");
 532     ss->a->ops->print(ss->a, ADDR_SRC, &d);
 533     dstr_puts(&d, " -> ");
 534     dstr_puts(&d, ss->t->desc);
 535     ss->s.desc = xstrdup(d.buf);
 536     dstr_destroy(&d);
 537   }
 538
 539   /* --- Confirm the address --- */
 540
 541   if (ss->a->ops->confirm)
 542     ss->a->ops->confirm(ss->a, ADDR_SRC, ss->ao);
 543
 544   /* --- Initialize the socket for listening --- */
 545
 546   if ((fd = ss->a->ops->bind(ss->a, ss->ao)) < 0)
 547     error(sc, "couldn't bind socket `%s': %s", ss->s.desc, strerror(errno));
 548
 549   /* --- Set it to listen for connections --- */
 550
 551   setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 552   fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 553   if (listen(fd, ss->o.listen)) {
 554     error(sc, "couldn't listen on socket `%s': %s",
 555           ss->s.desc, strerror(errno));
 556   }
 557
 558   /* --- We're ready to go now --- */
 559
 560   sel_initfile(sel, &ss->r, fd, SEL_READ, ss_accept, ss);
 561   sel_addfile(&ss->r);
 562   source_add(&ss->s);
 563   fw_inc();
 564 }
 565
 566 /* --- @destroy@ --- */
 567
 568 static void ssource_destroy(source *s)
 569 {
 570   ssource *ss = (ssource *)s;
 571
 572   if (ss->o.conn || ss->o.opt != SOCKOPT_LIMIT) {
 573     sel_rmfile(&ss->r);
 574     close(ss->r.fd);
 575     if (ss->a->ops->unbind)
 576       ss->a->ops->unbind(ss->a);
 577   }
 578   if (ss->a->ops->freesrcopts)
 579     ss->a->ops->freesrcopts(ss->ao);
 580   else
 581     DESTROY(ss->ao);
 582   xfree(ss->s.desc);
 583   ss->a->ops->destroy(ss->a);
 584   ss->t->ops->destroy(ss->t);
 585   source_remove(&ss->s);
 586   DESTROY(ss);
 587   fw_dec();
 588 }
 589
 590 /* --- Source definition block --- */
 591
 592 source_ops ssource_ops = {
 593   "socket",
 594   ssource_option, ssource_read, ssource_attach, ssource_destroy
 595 };
 596
 597 /*----- Target definition -------------------------------------------------*/
 598
 599 /* --- @options@ --- */
 600
 601 static int starget_option(target *t, scanner *sc)
 602 {
 603   starget *st = (starget *)t;
 604
 605   CONF_BEGIN(sc, "starget", "socket target")
 606
 607   /* --- Pass the option around the various address types --- */
 608
 609   if (st) {
 610     if (st->a->ops->option && st->a->ops->option(sc, st->ao, ADDR_DEST))
 611       CONF_ACCEPT;
 612   }
 613   /* We'd have done it already if it was global */
 614
 615   /* --- Done --- */
 616
 617   CONF_END;
 618 }
 619
 620 /* --- @read@ --- */
 621
 622 static target *starget_read(scanner *sc)
 623 {
 624   starget *st;
 625   dstr d = DSTR_INIT;
 626
 627   (void)(conf_prefix(sc, "socket") || conf_prefix(sc, "sk"));
 628   st = CREATE(starget);
 629   st->t.ops = &starget_ops;
 630   st->a = getaddr(sc, ADDR_DEST);
 631   if (st->a->ops->inittargopts)
 632     st->ao = st->a->ops->inittargopts();
 633   else {
 634     st->ao = CREATE(addr_opts);
 635     *st->ao = gtao;
 636   }
 637   dstr_puts(&d, "socket.");
 638   st->a->ops->print(st->a, ADDR_DEST, &d);
 639   st->t.desc = xstrdup(d.buf);
 640   dstr_destroy(&d);
 641   return (&st->t);
 642 }
 643
 644 /* --- @confirm@ --- */
 645
 646 static void starget_confirm(target *t)
 647 {
 648   starget *st = (starget *)t;
 649
 650   if (st->a->ops->confirm)
 651     st->a->ops->confirm(st->a, ADDR_DEST, st->ao);
 652 }
 653
 654 /* --- @create@ --- */
 655
 656 static endpt *starget_create(target *t, const char *desc)
 657 {
 658   starget *st = (starget *)t;
 659   stept *e = CREATE(stept);
 660
 661   e->e.ops = &stept_ops;
 662   e->e.other = 0;
 663   e->e.f = EPF_FILE | EPF_PENDING;
 664   e->e.t = 0;
 665   e->desc = xstrdup(desc);
 666   if (st->a->ops->connect(st->a, st->ao, &e->c, &e->e)) {
 667     fw_log(-1, "[%s] couldn't connect: %s", e->desc, strerror(errno));
 668     DESTROY(e);
 669     return (0);
 670   }
 671   fw_inc();
 672   return (&e->e);
 673 }
 674
 675 /* --- @destroy@ --- */
 676
 677 static void starget_destroy(target *t)
 678 {
 679   starget *st = (starget *)t;
 680   if (st->a->ops->freetargopts)
 681     st->a->ops->freetargopts(st->ao);
 682   else
 683     DESTROY(st->ao);
 684   st->a->ops->destroy(st->a);
 685   xfree(st->t.desc);
 686   DESTROY(st);
 687 }
 688
 689 /* --- Socket target definition block --- */
 690
 691 target_ops starget_ops = {
 692   "socket",
 693   starget_option, starget_read, starget_confirm,
 694   starget_create, starget_destroy
 695 };
 696
 697 /*----- That's all, folks -------------------------------------------------*/