3 * $Id: socket.c,v 1.5 2000/03/23 23:20:42 mdw Exp $
5 * Socket source and target definitions
7 * (c) 1999 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the `fw' port forwarder.
14 * `fw' is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * `fw' is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with `fw'; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.5 2000/03/23 23:20:42 mdw
33 * Remove listener even if connection option isn't SOCKOPT_LIMITED.
35 * Revision 1.4 1999/12/22 15:44:25 mdw
38 * Revision 1.3 1999/10/22 22:48:36 mdw
39 * New connection options: unlimited concurrent connections, and one-shot
42 * Revision 1.2 1999/07/27 18:30:53 mdw
43 * Various minor portability fixes.
45 * Revision 1.1 1999/07/26 23:33:32 mdw
46 * New sources and targets.
50 /*----- Header files ------------------------------------------------------*/
61 #include <sys/types.h>
64 #include <sys/socket.h>
65 #include <netinet/in.h>
66 #include <arpa/inet.h>
69 #include <mLib/alloc.h>
70 #include <mLib/conn.h>
71 #include <mLib/dstr.h>
72 #include <mLib/fdflags.h>
87 /*----- Data structures ---------------------------------------------------*/
89 /* --- Socket source options --- */
91 typedef struct ssource_opts {
96 static ssource_opts ssgo = { 256, 0 };
98 #define SOCKOPT_LIMIT 0u
99 #define SOCKOPT_NOLIMIT 1u
100 #define SOCKOPT_ONESHOT 2u
102 /* --- Socket source --- */
104 typedef struct ssource {
113 /* --- Socket target --- */
115 typedef struct starget {
121 /* --- Socket target endpoint --- */
123 typedef struct stept {
129 /* --- Socket source endpoint --- */
131 typedef struct ssept {
137 #define SKF_BROKEN 32u
139 /*----- Protocol table ----------------------------------------------------*/
141 static addr_ops *addrs[] = { &inet_ops, &un_ops, 0 };
143 /*----- Other persistent variables ----------------------------------------*/
145 static addr_opts gao = { 0 };
147 /*----- Parsing address types ---------------------------------------------*/
149 /* --- @getaddrtype@ --- *
151 * Arguments: @scanner *sc@ = pointer to scanner (for error reporting)
152 * @const char *p@ = pointer to protocol name
153 * @int abbrev@ = nonzero to allow abbreviations
155 * Returns: Pointer to address operations table or null.
157 * Use: Looks up a protocol name. Handy when parsing addresses and
158 * other bits of configuration. Returns null if no matching
162 static addr_ops *getaddrtype(scanner *sc, const char *p, int abbrev)
165 addr_ops *chosen = 0;
166 size_t sz = strlen(p);
168 for (ops = addrs; *ops; ops++) {
169 if (strncmp((*ops)->name, p, sz) == 0) {
170 if ((*ops)->name[sz] == 0)
172 else if (chosen && abbrev)
173 error(sc, "ambiguous socket address type `%s'", p);
182 /* --- @getaddr@ --- *
184 * Arguments: @scanner *sc@ = pointer to scanner to read from
185 * @unsigned type@ = address type (@ADDR_SRC@ or @ADDR_DEST@)
187 * Returns: Pointer to an address successfully read.
189 * Use: Reads an optionally qualified address.
192 static addr *getaddr(scanner *sc, unsigned type)
201 if (sc->t == CTOK_WORD)
202 ops = getaddrtype(sc, sc->d.buf, abbrev);
206 error(sc, "unknown socket address type `%s'", sc->d.buf);
212 return (ops->read(sc, type));
215 /*----- Socket endpoints --------------------------------------------------*/
217 /* --- @wclose@ --- */
219 static void sept_wclose(endpt *e)
221 shutdown(e->out->fd, 1);
224 /* --- @close@ (source) --- */
226 static void ss_listen(ssource */*ss*/);
228 static void ssept_close(endpt *e)
230 ssept *ee = (ssept *)e;
232 if (ee->s->o.opt == SOCKOPT_LIMIT) {
234 if (ee->s->o.conn == 1)
238 REFFD_DEC(ee->e.out);
243 /* --- @close@ (target) --- */
245 static void stept_close(endpt *e)
247 stept *ee = (stept *)e;
249 if (ee->e.f & EPF_PENDING) {
250 if (ee->e.f & SKF_CONN)
254 REFFD_DEC(ee->e.out);
261 /* --- @stept_go@ --- *
263 * Arguments: @int fd@ = file descriptor now ready for use
264 * @void *p@ = pointer to an endpoint structure
268 * Use: Handles successful connection of the target endpoint.
271 static void stept_go(int fd, void *p)
275 /* --- Complicated and subtle --- *
277 * This code interacts quite closely with @starget_create@, mainly through
278 * flags in the endpoint block.
280 * If the connection failed, I log a message (that's easy enough). The
281 * behaviour then depends on whether the endpoints have been joined yet.
282 * If not, I set @SKF_BROKEN@ and return, so that @starget_create@ can
283 * clean up the mess and return an immediate failure. If they have, I kill
284 * the connection and everything ought to work.
286 * If the connection worked, I clear @EPF_PENDING@ (as expected, because
287 * my endpoint is now ready), and @SKF_CONN@ (to let @starget_create@ know
288 * that the connection is already going). Then, only if this isn't the
289 * first attempt, I rejoin this endpoint to its partner.
293 fw_log(-1, "[%s] connection failed: %s", e->desc, strerror(errno));
295 if (e->e.f & EPF_PENDING)
298 e->e.f |= SKF_BROKEN;
300 reffd *r = reffd_init(fd);
302 e->e.in = e->e.out = r;
303 e->e.f &= ~(EPF_PENDING | SKF_CONN);
305 endpt_join(&e->e, e->e.other);
309 /* --- Socket endpoint definition --- */
311 static endpt_ops ssept_ops = {
312 0, 0, sept_wclose, ssept_close
315 static endpt_ops stept_ops = {
316 0, 0, sept_wclose, stept_close
319 /*----- Source definition -------------------------------------------------*/
321 /* --- @option@ --- */
323 static int ssource_option(source *s, scanner *sc)
325 ssource *ss = (ssource *)s;
326 ssource_opts *sso = ss ? &ss->o : &ssgo;
328 CONF_BEGIN(sc, "socket", "socket")
330 /* --- Make sure the next token is a word --- */
332 if (sc->t != CTOK_WORD)
333 error(sc, "parse error, option keyword expected");
335 /* --- Handle options at this level --- */
337 if (strcmp(sc->d.buf, "conn") == 0) {
341 if (sc->t != CTOK_WORD)
342 error(sc, "parse error, expected `unlimited', `one-shot' or number");
343 if (isdigit((unsigned char)sc->d.buf[0])) {
344 sso->conn = atoi(sc->d.buf);
346 error(sc, "argument of `conn' must be positive");
347 sso->opt = SOCKOPT_LIMIT;
351 sso->opt = 1 + (1 & conf_enum(sc,
352 "unlimited,one-shot,infinite",
353 ENUM_ABBREV, "`conn' option"));
358 if (strcmp(sc->d.buf, "logging") == 0 ||
359 strcmp(sc->d.buf, "log") == 0) {
360 addr_opts *ao = ss ? ss->ao : &gao;
364 if (conf_enum(sc, "no,yes", ENUM_ABBREV, "logging status"))
365 ao->f &= ~ADDRF_NOLOG;
367 ao->f |= ADDRF_NOLOG;
371 /* --- Pass the option around the various address types --- */
374 if (ss->a->ops->option && ss->a->ops->option(sc, ss ? ss->ao : 0))
378 for (a = addrs; *a; a++) {
379 if ((*a)->option && (*a)->option(sc, 0))
384 /* --- Nobody understood the option --- */
391 static source *ssource_read(scanner *sc)
395 (void)(conf_prefix(sc, "socket") || conf_prefix(sc, "sk"));
396 ss = CREATE(ssource);
397 ss->s.ops = &ssource_ops;
400 ss->a = getaddr(sc, ADDR_SRC);
401 if (ss->a->ops->initopts)
402 ss->ao = ss->a->ops->initopts();
404 ss->ao = CREATE(addr_opts);
410 /* --- @ss_accept@ --- *
412 * Arguments: @int fd@ = file descriptor to accept from
413 * @unsigned mode@ = what's ready with the descriptor
414 * @void *p@ = pointer to the source definition
418 * Use: Accepts an incoming connection and attaches it to a target
422 static void ssource_destroy(source */*s*/);
424 static void ss_accept(int fd, unsigned mode, void *p)
431 /* --- Make the file descriptor --- */
435 if ((r = ss->a->ops->accept(fd, ss->ao, ss->s.desc)) == 0)
437 setsockopt(r->fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
438 fdflags(r->fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
441 /* --- Make an endpoint --- */
444 e->e.ops = &ssept_ops;
448 e->e.in = e->e.out = r;
452 /* --- Obtain the target endpoint and let rip --- */
454 if ((ee = ss->t->ops->create(ss->t, ss->s.desc)) == 0) {
462 /* --- Remove the listening socket if necessary --- */
468 if (!(ss->ao->f & ADDRF_NOLOG))
469 fw_log(-1, "[%s] maximum connections reached", ss->s.desc);
472 if (ss->a->ops->unbind)
473 ss->a->ops->unbind(ss->a);
476 case SOCKOPT_NOLIMIT:
478 case SOCKOPT_ONESHOT:
481 if (ss->a->ops->unbind)
482 ss->a->ops->unbind(ss->a);
483 ssource_destroy(&ss->s);
487 /* --- Let everything else happen --- */
489 endpt_join(&e->e, ee);
492 /* --- @ss_listen@ --- *
494 * Arguments: @ssource *ss@ = source to listen on
498 * Use: Sets the socket to listen again, if it stopped for some
499 * reason. This is a copy of the code in the @read@ function,
500 * because it has different (wildly different) error handling
504 static void ss_listen(ssource *ss)
506 gen_addr *ga = (gen_addr *)ss->a;
509 if (!(ss->ao->f & ADDRF_NOLOG))
510 fw_log(-1, "[%s] reattaching listener", ss->s.desc);
512 /* --- Make the socket --- */
514 if ((fd = socket(ga->a.ops->pf, SOCK_STREAM, 0)) < 0) {
515 fw_log(-1, "[%s] couldn't create socket: %s",
516 ss->s.desc, strerror(errno));
520 /* --- Set it to allow address reuse --- */
524 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
525 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
528 /* --- Bind it to the right port --- */
530 if (bind(fd, &ga->sa, ga->a.sz)) {
531 fw_log(-1, "[%s] couldn't bind socket: %s", ss->s.desc, strerror(errno));
534 if (ga->a.ops->bound)
535 ga->a.ops->bound(&ga->a, ss->ao);
537 /* --- Set it to listen for connections --- */
540 fw_log(-1, "[%s] couldn't listen on socket: %s",
541 ss->s.desc, strerror(errno));
545 /* --- Set the listener up again --- */
551 /* --- Tidy up if it failed --- *
553 * I'll just remove the entire source.
560 ssource_destroy(&ss->s);
563 /* --- @attach@ --- */
565 static void ssource_attach(source *s, scanner *sc, target *t)
567 ssource *ss = (ssource *)s;
572 /* --- Initialize the description string --- */
576 dstr_puts(&d, "socket.");
577 ss->a->ops->print(ss->a, ADDR_SRC, &d);
578 dstr_puts(&d, " -> ");
579 dstr_puts(&d, ss->t->desc);
580 ss->s.desc = xstrdup(d.buf);
584 /* --- Initialize the socket for listening --- */
587 gen_addr *ga = (gen_addr *)ss->a;
589 /* --- Make the socket --- */
591 if ((fd = socket(ga->a.ops->pf, SOCK_STREAM, 0)) < 0)
592 error(sc, "couldn't create socket: %s", strerror(errno));
594 /* --- Set it to allow address reuse --- */
598 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
599 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
602 /* --- Bind it to the right port --- */
604 if (bind(fd, &ga->sa, ga->a.sz))
605 error(sc, "couldn't bind to %s: %s", ss->s.desc, strerror(errno));
606 if (ga->a.ops->bound)
607 ga->a.ops->bound(&ga->a, ss->ao);
609 /* --- Set it to listen for connections --- */
612 error(sc, "couldn't listen on socket: %s", strerror(errno));
615 /* --- We're ready to go now --- */
617 sel_initfile(sel, &ss->r, fd, SEL_READ, ss_accept, ss);
623 /* --- @destroy@ --- */
625 static void ssource_destroy(source *s)
627 ssource *ss = (ssource *)s;
629 if (ss->o.conn || ss->o.opt != SOCKOPT_LIMIT) {
632 if (ss->a->ops->unbind)
633 ss->a->ops->unbind(ss->a);
635 if (ss->a->ops->freeopts)
636 ss->a->ops->freeopts(ss->ao);
639 /* free(ss->s.desc); */
640 ss->a->ops->destroy(ss->a);
641 ss->t->ops->destroy(ss->t);
642 source_remove(&ss->s);
647 /* --- Source definition block --- */
649 source_ops ssource_ops = {
651 ssource_option, ssource_read, ssource_attach, ssource_destroy
654 /*----- Target definition -------------------------------------------------*/
658 static target *starget_read(scanner *sc)
663 (void)(conf_prefix(sc, "socket") || conf_prefix(sc, "sk"));
664 st = CREATE(starget);
665 st->t.ops = &starget_ops;
666 st->a = getaddr(sc, ADDR_DEST);
667 dstr_puts(&d, "socket.");
668 st->a->ops->print(st->a, ADDR_DEST, &d);
669 st->t.desc = xstrdup(d.buf);
674 /* --- @create@ --- *
676 * Arguments: @target *t@ = pointer to target
677 * @const char *desc@ = description of connection
679 * Returns: Pointer to a created endpoint.
681 * Use: Generates a target endpoint for communication.
684 static endpt *starget_create(target *t, const char *desc)
686 starget *st = (starget *)t;
687 stept *e = CREATE(stept);
689 gen_addr *ga = (gen_addr *)st->a;
692 if ((fd = socket(st->a->ops->pf, SOCK_STREAM, 0)) < 0)
694 setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
695 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
696 e->e.ops = &stept_ops;
698 e->e.f = EPF_FILE | SKF_CONN;
702 /* --- Pay attention --- *
704 * This bit is quite subtle. The connect can succeed or fail later: that's
705 * fine. The problem comes if it makes its mind up right now. The flag
706 * @SKF_CONN@ signifies that I'm trying to connect. I set it up to begin
707 * with and @stept_go@ turns it off when it's done: @stept_close@ uses it
708 * to decide whether to kill the connection. The flag @EPF_PENDING@ is
709 * only set after @conn_init@ returns and @SKF_CONN@ is still set (meaning
710 * that the connection is still in progress). That's used to let
711 * @stept_go@ know whether to kill the other endpoint. The flag
712 * @SKF_BROKEN@ is used to signify an immediate failure.
715 conn_init(&e->c, sel, fd, &ga->sa, ga->a.sz, stept_go, e);
716 if (e->e.f & SKF_BROKEN) {
720 if (e->e.f & SKF_CONN)
721 e->e.f |= EPF_PENDING;
726 /* --- @destroy@ --- */
728 static void starget_destroy(target *t)
730 starget *st = (starget *)t;
731 st->a->ops->destroy(st->a);
732 /* free(st->t.desc); */
736 /* --- Socket target definition block --- */
738 target_ops starget_ops = {
740 0, starget_read, starget_create, starget_destroy
743 /*----- That's all, folks -------------------------------------------------*/