3 * $Id: endpt.c,v 1.2 1999/10/22 22:46:17 mdw Exp $
5 * Generic endpoint abstraction
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 1.2 1999/10/22 22:46:17 mdw
33 * When a non-file endpoint is attached to a file, keep the file endpoint
34 * open until the nonfile is done. This stops socket sources from
35 * resetting their connection limits too early.
37 * Revision 1.1 1999/07/26 23:33:01 mdw
38 * Infrastructure for the new design.
42 /*----- Header files ------------------------------------------------------*/
51 #include <sys/types.h>
58 /*----- Data structures ---------------------------------------------------*/
60 /* --- Pairs of channels --- *
62 * Channels are always allocated and freed in pairs. It makes sense to keep
63 * the pair together. (It also wastes less memory.)
66 typedef struct chanpair {
67 struct chanpair *next;
71 /* --- The `private data structure' --- *
73 * This is called a @tango@ because it takes two (endpoints).
76 typedef struct tango {
77 struct tango *next, *prev; /* A big list of all tangos */
78 endpt *a, *b; /* The two endpoints */
79 unsigned s; /* State of the connection */
80 chanpair *c; /* The pair of channels */
86 /*----- Static variables --------------------------------------------------*/
88 static chanpair *chans = 0; /* List of spare channel pairs */
89 static tango *tangos = 0; /* List of tangos */
91 /*----- Main code ---------------------------------------------------------*/
93 /* --- @doneab@, @doneba@ --- *
95 * Arguments: @void *p@ = pointer to a tango block
99 * Use: Handles completion of a channel.
102 static void doneab(void *p)
106 t->b->ops->wclose(t->b);
111 static void doneba(void *p)
115 t->a->ops->wclose(t->a);
120 /* --- @endpt_kill@ --- *
122 * Arguments: @endpt *a@ = an endpoint
126 * Use: Kills an endpoint. If the endpoint is joined to another, the
127 * other endpoint is also killed, as is the connection between
128 * them (and that's the tricky bit).
131 void endpt_kill(endpt *a)
136 /* --- If the endpont is unconnected, just close it --- */
146 /* --- See whether to close channels --- *
148 * I'll only have opened channels if both things are files. Also, the
149 * channel from @b@ to @a@ will only be open if @b@ is not pending.
152 if (a->f & b->f & EPF_FILE) {
154 chan_close(&t->c->ab);
155 if (!(b->f & EPF_PENDING) && (t->s & EPS_BA))
156 chan_close(&t->c->ba);
161 /* --- Now just throw the endpoints and tango block away --- */
166 t->next->prev = t->prev;
168 t->prev->next = t->next;
174 /* --- @endpt_killall@ --- *
180 * Use: Destroys all current endpoint connections. Used when
184 void endpt_killall(void)
195 /* --- @endpt_join@ --- *
197 * Arguments: @endpt *a@ = pointer to first endpoint
198 * @endpt *b@ = pointer to second endpoint
202 * Use: Joins two endpoints together. It's OK to join endpoints
203 * which are already joined; in fact, the the right thing to do
204 * when your endpoint decides that it's not pending any more is
205 * to join it to its partner again.
208 void endpt_join(endpt *a, endpt *b)
212 /* --- If there is no tango yet, create one --- */
221 t->s = EPS_AB | EPS_BA;
228 /* --- If both endpoints are unfinished, leave them for a while --- */
230 if (a->f & b->f & EPF_PENDING)
233 /* --- At least one endpoint is ready --- *
235 * If both endpoints are files then I can speculatively create the
236 * channels, which will let data start flowing a bit. Otherwise, I'll just
237 * have to wait some more.
240 if ((a->f | b->f) & EPF_PENDING) {
242 /* --- Only be interested if both things are files --- */
244 if (!t->c && (a->f & b->f & EPF_FILE)) {
246 /* --- Allocate a pair of channels --- */
249 t->c = xmalloc(sizeof(*t->c));
255 /* --- Make @a@ the endpoint which is ready --- */
257 if (a->f & EPF_PENDING) {
262 /* --- Open one channel to read from @a@ --- */
264 chan_open(&t->c->ab, a->in->fd, -1, doneab, t);
269 /* --- Both endpoints are now ready --- *
271 * There are four cases to consider here.
276 * Neither endpoint is a file. I need to make a pair of pipes and tell
277 * both endpoints to attach to them. I can then close the pipes and
281 if (!((a->f | b->f) & EPF_FILE)) {
283 reffd *rab, *wab, *rba, *wba;
285 /* --- Create the pipes --- */
287 if (pipe(pab)) goto tidy_nofile_0;
288 if (pipe(pba)) goto tidy_nofile_1;
290 /* --- Attach reference counters --- */
292 rab = reffd_init(pab[0]); wab = reffd_init(pab[1]);
293 rba = reffd_init(pba[0]); wba = reffd_init(pba[1]);
294 a->ops->attach(a, rba, wab);
295 b->ops->attach(b, rab, wba);
296 REFFD_DEC(rab); REFFD_DEC(wab);
297 REFFD_DEC(rba); REFFD_DEC(wba);
300 /* --- Tidy up after a mess --- */
303 close(pab[0]); close(pab[1]);
308 t->next->prev = t->prev;
310 t->prev->next = t->next;
319 * One endpoint is a file, the other isn't. I just attach the other
320 * endpoint to the file and stand well back.
323 if ((a->f ^ b->f) & EPF_FILE) {
325 /* --- Let @a@ be the endpoint with the file --- */
327 if (b->f & EPF_FILE) {
332 /* --- Attach the non-file endpoint to the file and run away --- *
334 * Leave it as the non-file's responsibility to close the other endpoint
335 * when it's ready. It should also close itself at that time.
338 b->ops->attach(b, a->in, a->out);
341 t->next->prev = t->prev;
343 t->prev->next = t->next;
352 * Both endpoints are files and I have a partially created channel pair. I
353 * need to create the other channel and add a destination to the first one.
354 * In this case, @t->b@ is the endpoint which has just finished setting
360 chan_open(&t->c->ba, b->in->fd, a->out->fd, doneba, t);
361 chan_dest(&t->c->ab, b->out->fd);
367 * Both endpoints are files and I don't have a partially created channel
368 * pair. I need to allocate a channel pair and create both channels.
372 t->c = xmalloc(sizeof(*t->c));
377 chan_open(&t->c->ab, a->in->fd, b->out->fd, doneab, t);
378 chan_open(&t->c->ba, b->in->fd, a->out->fd, doneba, t);
382 /*----- That's all, folks -------------------------------------------------*/