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1/*
2 * Copyright (c) 1999 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
26RCSID("$OpenBSD: nchan.c,v 1.23 2001/02/28 08:54:55 markus Exp $");
27
28#include "ssh1.h"
29#include "ssh2.h"
30#include "buffer.h"
31#include "packet.h"
32#include "channels.h"
33#include "nchan.h"
34#include "compat.h"
35#include "log.h"
36
37/* functions manipulating channel states */
38/*
39 * EVENTS update channel input/output states execute ACTIONS
40 */
41/* events concerning the INPUT from socket for channel (istate) */
42chan_event_fn *chan_rcvd_oclose = NULL;
43chan_event_fn *chan_read_failed = NULL;
44chan_event_fn *chan_ibuf_empty = NULL;
45/* events concerning the OUTPUT from channel for socket (ostate) */
46chan_event_fn *chan_rcvd_ieof = NULL;
47chan_event_fn *chan_write_failed = NULL;
48chan_event_fn *chan_obuf_empty = NULL;
49/*
50 * ACTIONS: should never update the channel states
51 */
52static void chan_send_ieof1(Channel *c);
53static void chan_send_oclose1(Channel *c);
54static void chan_send_close2(Channel *c);
55static void chan_send_eof2(Channel *c);
56
57/* helper */
58static void chan_shutdown_write(Channel *c);
59static void chan_shutdown_read(Channel *c);
60
61/*
62 * SSH1 specific implementation of event functions
63 */
64
65static void
66chan_rcvd_oclose1(Channel *c)
67{
68 debug("channel %d: rcvd oclose", c->self);
69 switch (c->istate) {
70 case CHAN_INPUT_WAIT_OCLOSE:
71 debug("channel %d: input wait_oclose -> closed", c->self);
72 c->istate = CHAN_INPUT_CLOSED;
73 break;
74 case CHAN_INPUT_OPEN:
75 debug("channel %d: input open -> closed", c->self);
76 chan_shutdown_read(c);
77 chan_send_ieof1(c);
78 c->istate = CHAN_INPUT_CLOSED;
79 break;
80 case CHAN_INPUT_WAIT_DRAIN:
81 /* both local read_failed and remote write_failed */
82 log("channel %d: input drain -> closed", c->self);
83 chan_send_ieof1(c);
84 c->istate = CHAN_INPUT_CLOSED;
85 break;
86 default:
87 error("channel %d: protocol error: chan_rcvd_oclose for istate %d",
88 c->self, c->istate);
89 return;
90 }
91}
92static void
93chan_read_failed_12(Channel *c)
94{
95 debug("channel %d: read failed", c->self);
96 switch (c->istate) {
97 case CHAN_INPUT_OPEN:
98 debug("channel %d: input open -> drain", c->self);
99 chan_shutdown_read(c);
100 c->istate = CHAN_INPUT_WAIT_DRAIN;
101 if (buffer_len(&c->input) == 0) {
102 debug("channel %d: input: no drain shortcut", c->self);
103 chan_ibuf_empty(c);
104 }
105 break;
106 default:
107 error("channel %d: internal error: we do not read, but chan_read_failed for istate %d",
108 c->self, c->istate);
109 break;
110 }
111}
112static void
113chan_ibuf_empty1(Channel *c)
114{
115 debug("channel %d: ibuf empty", c->self);
116 if (buffer_len(&c->input)) {
117 error("channel %d: internal error: chan_ibuf_empty for non empty buffer",
118 c->self);
119 return;
120 }
121 switch (c->istate) {
122 case CHAN_INPUT_WAIT_DRAIN:
123 debug("channel %d: input drain -> wait_oclose", c->self);
124 chan_send_ieof1(c);
125 c->istate = CHAN_INPUT_WAIT_OCLOSE;
126 break;
127 default:
128 error("channel %d: internal error: chan_ibuf_empty for istate %d",
129 c->self, c->istate);
130 break;
131 }
132}
133static void
134chan_rcvd_ieof1(Channel *c)
135{
136 debug("channel %d: rcvd ieof", c->self);
137 if (c->type != SSH_CHANNEL_OPEN) {
138 debug("channel %d: non-open", c->self);
139 if (c->istate == CHAN_INPUT_OPEN) {
140 debug("channel %d: non-open: input open -> wait_oclose", c->self);
141 chan_shutdown_read(c);
142 chan_send_ieof1(c);
143 c->istate = CHAN_INPUT_WAIT_OCLOSE;
144 } else {
145 error("channel %d: istate %d != open", c->self, c->istate);
146 }
147 if (c->ostate == CHAN_OUTPUT_OPEN) {
148 debug("channel %d: non-open: output open -> closed", c->self);
149 chan_send_oclose1(c);
150 c->ostate = CHAN_OUTPUT_CLOSED;
151 } else {
152 error("channel %d: ostate %d != open", c->self, c->ostate);
153 }
154 return;
155 }
156 switch (c->ostate) {
157 case CHAN_OUTPUT_OPEN:
158 debug("channel %d: output open -> drain", c->self);
159 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
160 break;
161 case CHAN_OUTPUT_WAIT_IEOF:
162 debug("channel %d: output wait_ieof -> closed", c->self);
163 c->ostate = CHAN_OUTPUT_CLOSED;
164 break;
165 default:
166 error("channel %d: protocol error: chan_rcvd_ieof for ostate %d",
167 c->self, c->ostate);
168 break;
169 }
170}
171static void
172chan_write_failed1(Channel *c)
173{
174 debug("channel %d: write failed", c->self);
175 switch (c->ostate) {
176 case CHAN_OUTPUT_OPEN:
177 debug("channel %d: output open -> wait_ieof", c->self);
178 chan_send_oclose1(c);
179 c->ostate = CHAN_OUTPUT_WAIT_IEOF;
180 break;
181 case CHAN_OUTPUT_WAIT_DRAIN:
182 debug("channel %d: output wait_drain -> closed", c->self);
183 chan_send_oclose1(c);
184 c->ostate = CHAN_OUTPUT_CLOSED;
185 break;
186 default:
187 error("channel %d: internal error: chan_write_failed for ostate %d",
188 c->self, c->ostate);
189 break;
190 }
191}
192static void
193chan_obuf_empty1(Channel *c)
194{
195 debug("channel %d: obuf empty", c->self);
196 if (buffer_len(&c->output)) {
197 error("channel %d: internal error: chan_obuf_empty for non empty buffer",
198 c->self);
199 return;
200 }
201 switch (c->ostate) {
202 case CHAN_OUTPUT_WAIT_DRAIN:
203 debug("channel %d: output drain -> closed", c->self);
204 chan_send_oclose1(c);
205 c->ostate = CHAN_OUTPUT_CLOSED;
206 break;
207 default:
208 error("channel %d: internal error: chan_obuf_empty for ostate %d",
209 c->self, c->ostate);
210 break;
211 }
212}
213static void
214chan_send_ieof1(Channel *c)
215{
216 debug("channel %d: send ieof", c->self);
217 switch (c->istate) {
218 case CHAN_INPUT_OPEN:
219 case CHAN_INPUT_WAIT_DRAIN:
220 packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
221 packet_put_int(c->remote_id);
222 packet_send();
223 break;
224 default:
225 error("channel %d: internal error: cannot send ieof for istate %d",
226 c->self, c->istate);
227 break;
228 }
229}
230static void
231chan_send_oclose1(Channel *c)
232{
233 debug("channel %d: send oclose", c->self);
234 switch (c->ostate) {
235 case CHAN_OUTPUT_OPEN:
236 case CHAN_OUTPUT_WAIT_DRAIN:
237 chan_shutdown_write(c);
238 buffer_consume(&c->output, buffer_len(&c->output));
239 packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
240 packet_put_int(c->remote_id);
241 packet_send();
242 break;
243 default:
244 error("channel %d: internal error: cannot send oclose for ostate %d",
245 c->self, c->ostate);
246 break;
247 }
248}
249
250/*
251 * the same for SSH2
252 */
253static void
254chan_rcvd_oclose2(Channel *c)
255{
256 debug("channel %d: rcvd close", c->self);
257 if (c->flags & CHAN_CLOSE_RCVD)
258 error("channel %d: protocol error: close rcvd twice", c->self);
259 c->flags |= CHAN_CLOSE_RCVD;
260 if (c->type == SSH_CHANNEL_LARVAL) {
261 /* tear down larval channels immediately */
262 c->ostate = CHAN_OUTPUT_CLOSED;
263 c->istate = CHAN_INPUT_CLOSED;
264 return;
265 }
266 switch (c->ostate) {
267 case CHAN_OUTPUT_OPEN:
268 /* wait until a data from the channel is consumed if a CLOSE is received */
269 debug("channel %d: output open -> drain", c->self);
270 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
271 break;
272 }
273 switch (c->istate) {
274 case CHAN_INPUT_OPEN:
275 debug("channel %d: input open -> closed", c->self);
276 chan_shutdown_read(c);
277 break;
278 case CHAN_INPUT_WAIT_DRAIN:
279 debug("channel %d: input drain -> closed", c->self);
280 chan_send_eof2(c);
281 break;
282 }
283 c->istate = CHAN_INPUT_CLOSED;
284}
285static void
286chan_ibuf_empty2(Channel *c)
287{
288 debug("channel %d: ibuf empty", c->self);
289 if (buffer_len(&c->input)) {
290 error("channel %d: internal error: chan_ibuf_empty for non empty buffer",
291 c->self);
292 return;
293 }
294 switch (c->istate) {
295 case CHAN_INPUT_WAIT_DRAIN:
296 debug("channel %d: input drain -> closed", c->self);
297 if (!(c->flags & CHAN_CLOSE_SENT))
298 chan_send_eof2(c);
299 c->istate = CHAN_INPUT_CLOSED;
300 break;
301 default:
302 error("channel %d: internal error: chan_ibuf_empty for istate %d",
303 c->self, c->istate);
304 break;
305 }
306}
307static void
308chan_rcvd_ieof2(Channel *c)
309{
310 debug("channel %d: rcvd eof", c->self);
311 if (c->ostate == CHAN_OUTPUT_OPEN) {
312 debug("channel %d: output open -> drain", c->self);
313 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
314 }
315}
316static void
317chan_write_failed2(Channel *c)
318{
319 debug("channel %d: write failed", c->self);
320 switch (c->ostate) {
321 case CHAN_OUTPUT_OPEN:
322 debug("channel %d: output open -> closed", c->self);
323 chan_shutdown_write(c); /* ?? */
324 c->ostate = CHAN_OUTPUT_CLOSED;
325 break;
326 case CHAN_OUTPUT_WAIT_DRAIN:
327 debug("channel %d: output drain -> closed", c->self);
328 chan_shutdown_write(c);
329 c->ostate = CHAN_OUTPUT_CLOSED;
330 break;
331 default:
332 error("channel %d: internal error: chan_write_failed for ostate %d",
333 c->self, c->ostate);
334 break;
335 }
336}
337static void
338chan_obuf_empty2(Channel *c)
339{
340 debug("channel %d: obuf empty", c->self);
341 if (buffer_len(&c->output)) {
342 error("internal error: chan_obuf_empty %d for non empty buffer",
343 c->self);
344 return;
345 }
346 switch (c->ostate) {
347 case CHAN_OUTPUT_WAIT_DRAIN:
348 debug("channel %d: output drain -> closed", c->self);
349 chan_shutdown_write(c);
350 c->ostate = CHAN_OUTPUT_CLOSED;
351 break;
352 default:
353 error("channel %d: internal error: chan_obuf_empty for ostate %d",
354 c->self, c->ostate);
355 break;
356 }
357}
358static void
359chan_send_eof2(Channel *c)
360{
361 debug("channel %d: send eof", c->self);
362 switch (c->istate) {
363 case CHAN_INPUT_WAIT_DRAIN:
364 packet_start(SSH2_MSG_CHANNEL_EOF);
365 packet_put_int(c->remote_id);
366 packet_send();
367 break;
368 default:
369 error("channel %d: internal error: cannot send eof for istate %d",
370 c->self, c->istate);
371 break;
372 }
373}
374static void
375chan_send_close2(Channel *c)
376{
377 debug("channel %d: send close", c->self);
378 if (c->ostate != CHAN_OUTPUT_CLOSED ||
379 c->istate != CHAN_INPUT_CLOSED) {
380 error("channel %d: internal error: cannot send close for istate/ostate %d/%d",
381 c->self, c->istate, c->ostate);
382 } else if (c->flags & CHAN_CLOSE_SENT) {
383 error("channel %d: internal error: already sent close", c->self);
384 } else {
385 packet_start(SSH2_MSG_CHANNEL_CLOSE);
386 packet_put_int(c->remote_id);
387 packet_send();
388 c->flags |= CHAN_CLOSE_SENT;
389 }
390}
391
392/* shared */
393
394int
395chan_is_dead(Channel *c)
396{
397 if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
398 return 0;
399 if (!compat20) {
400 debug("channel %d: is dead", c->self);
401 return 1;
402 }
403 /*
404 * we have to delay the close message if the efd (for stderr) is
405 * still active
406 */
407 if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
408 buffer_len(&c->extended) > 0)
409#if 0
410 || ((c->extended_usage == CHAN_EXTENDED_READ) &&
411 c->efd != -1)
412#endif
413 ) {
414 debug2("channel %d: active efd: %d len %d type %s",
415 c->self, c->efd, buffer_len(&c->extended),
416 c->extended_usage==CHAN_EXTENDED_READ ?
417 "read": "write");
418 } else {
419 if (!(c->flags & CHAN_CLOSE_SENT)) {
420 chan_send_close2(c);
421 }
422 if ((c->flags & CHAN_CLOSE_SENT) &&
423 (c->flags & CHAN_CLOSE_RCVD)) {
424 debug("channel %d: is dead", c->self);
425 return 1;
426 }
427 }
428 return 0;
429}
430
431void
432chan_init_iostates(Channel *c)
433{
434 c->ostate = CHAN_OUTPUT_OPEN;
435 c->istate = CHAN_INPUT_OPEN;
436 c->flags = 0;
437}
438
439/* init */
440void
441chan_init(void)
442{
443 if (compat20) {
444 chan_rcvd_oclose = chan_rcvd_oclose2;
445 chan_read_failed = chan_read_failed_12;
446 chan_ibuf_empty = chan_ibuf_empty2;
447
448 chan_rcvd_ieof = chan_rcvd_ieof2;
449 chan_write_failed = chan_write_failed2;
450 chan_obuf_empty = chan_obuf_empty2;
451 } else {
452 chan_rcvd_oclose = chan_rcvd_oclose1;
453 chan_read_failed = chan_read_failed_12;
454 chan_ibuf_empty = chan_ibuf_empty1;
455
456 chan_rcvd_ieof = chan_rcvd_ieof1;
457 chan_write_failed = chan_write_failed1;
458 chan_obuf_empty = chan_obuf_empty1;
459 }
460}
461
462/* helper */
463static void
464chan_shutdown_write(Channel *c)
465{
466 buffer_consume(&c->output, buffer_len(&c->output));
467 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
468 return;
469 /* shutdown failure is allowed if write failed already */
470 debug("channel %d: close_write", c->self);
471 if (c->sock != -1) {
472 if (shutdown(c->sock, SHUT_WR) < 0)
473 debug("channel %d: chan_shutdown_write: shutdown() failed for fd%d: %.100s",
474 c->self, c->sock, strerror(errno));
475 } else {
476 if (close(c->wfd) < 0)
477 log("channel %d: chan_shutdown_write: close() failed for fd%d: %.100s",
478 c->self, c->wfd, strerror(errno));
479 c->wfd = -1;
480 }
481}
482static void
483chan_shutdown_read(Channel *c)
484{
485 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
486 return;
487 debug("channel %d: close_read", c->self);
488 if (c->sock != -1) {
489 /*
490 * shutdown(sock, SHUT_READ) may return ENOTCONN if the
491 * write side has been closed already. (bug on Linux)
492 * HP-UX will return EINVAL.
493 */
494 if (shutdown(c->sock, SHUT_RD) < 0
495 && (errno != ENOTCONN && errno != EINVAL))
496 error("channel %d: chan_shutdown_read: shutdown() failed for fd%d [i%d o%d]: %.100s",
497 c->self, c->sock, c->istate, c->ostate, strerror(errno));
498 } else {
499 if (close(c->rfd) < 0)
500 log("channel %d: chan_shutdown_read: close() failed for fd%d: %.100s",
501 c->self, c->rfd, strerror(errno));
502 c->rfd = -1;
503 }
504}