2 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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.
26 RCSID("$OpenBSD: nchan.c,v 1.35 2002/01/10 12:38:26 markus Exp $");
37 * SSH Protocol 1.5 aka New Channel Protocol
38 * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
39 * Written by Markus Friedl in October 1999
41 * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
42 * tear down of channels:
44 * 1.3: strict request-ack-protocol:
48 * 1.5: uses variations of:
53 * i.e. both sides have to close the channel
55 * 2.0: the EOF messages are optional
57 * See the debugging output from 'ssh -v' and 'sshd -d' of
58 * ssh-1.2.27 as an example.
62 /* functions manipulating channel states */
64 * EVENTS update channel input/output states execute ACTIONS
66 /* events concerning the INPUT from socket for channel (istate) */
67 chan_event_fn *chan_rcvd_oclose = NULL;
68 chan_event_fn *chan_read_failed = NULL;
69 chan_event_fn *chan_ibuf_empty = NULL;
70 /* events concerning the OUTPUT from channel for socket (ostate) */
71 chan_event_fn *chan_rcvd_ieof = NULL;
72 chan_event_fn *chan_write_failed = NULL;
73 chan_event_fn *chan_obuf_empty = NULL;
75 * ACTIONS: should never update the channel states
77 static void chan_send_ieof1(Channel *);
78 static void chan_send_oclose1(Channel *);
79 static void chan_send_close2(Channel *);
80 static void chan_send_eof2(Channel *);
83 static void chan_shutdown_write(Channel *);
84 static void chan_shutdown_read(Channel *);
87 * SSH1 specific implementation of event functions
91 chan_rcvd_oclose1(Channel *c)
93 debug("channel %d: rcvd oclose", c->self);
95 case CHAN_INPUT_WAIT_OCLOSE:
96 debug("channel %d: input wait_oclose -> closed", c->self);
97 c->istate = CHAN_INPUT_CLOSED;
100 debug("channel %d: input open -> closed", c->self);
101 chan_shutdown_read(c);
103 c->istate = CHAN_INPUT_CLOSED;
105 case CHAN_INPUT_WAIT_DRAIN:
106 /* both local read_failed and remote write_failed */
107 log("channel %d: input drain -> closed", c->self);
109 c->istate = CHAN_INPUT_CLOSED;
112 error("channel %d: protocol error: rcvd_oclose for istate %d",
118 chan_read_failed_12(Channel *c)
120 debug("channel %d: read failed", c->self);
122 case CHAN_INPUT_OPEN:
123 debug("channel %d: input open -> drain", c->self);
124 chan_shutdown_read(c);
125 c->istate = CHAN_INPUT_WAIT_DRAIN;
128 error("channel %d: chan_read_failed for istate %d",
134 chan_ibuf_empty1(Channel *c)
136 debug("channel %d: ibuf empty", c->self);
137 if (buffer_len(&c->input)) {
138 error("channel %d: chan_ibuf_empty for non empty buffer",
143 case CHAN_INPUT_WAIT_DRAIN:
144 debug("channel %d: input drain -> wait_oclose", c->self);
146 c->istate = CHAN_INPUT_WAIT_OCLOSE;
149 error("channel %d: chan_ibuf_empty for istate %d",
155 chan_rcvd_ieof1(Channel *c)
157 debug("channel %d: rcvd ieof", c->self);
158 if (c->type != SSH_CHANNEL_OPEN) {
159 debug("channel %d: non-open", c->self);
160 if (c->istate == CHAN_INPUT_OPEN) {
161 debug("channel %d: non-open: input open -> wait_oclose",
163 chan_shutdown_read(c);
165 c->istate = CHAN_INPUT_WAIT_OCLOSE;
167 error("channel %d: non-open: istate %d != open",
170 if (c->ostate == CHAN_OUTPUT_OPEN) {
171 debug("channel %d: non-open: output open -> closed",
173 chan_send_oclose1(c);
174 c->ostate = CHAN_OUTPUT_CLOSED;
176 error("channel %d: non-open: ostate %d != open",
182 case CHAN_OUTPUT_OPEN:
183 debug("channel %d: output open -> drain", c->self);
184 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
186 case CHAN_OUTPUT_WAIT_IEOF:
187 debug("channel %d: output wait_ieof -> closed", c->self);
188 c->ostate = CHAN_OUTPUT_CLOSED;
191 error("channel %d: protocol error: rcvd_ieof for ostate %d",
197 chan_write_failed1(Channel *c)
199 debug("channel %d: write failed", c->self);
201 case CHAN_OUTPUT_OPEN:
202 debug("channel %d: output open -> wait_ieof", c->self);
203 chan_send_oclose1(c);
204 c->ostate = CHAN_OUTPUT_WAIT_IEOF;
206 case CHAN_OUTPUT_WAIT_DRAIN:
207 debug("channel %d: output wait_drain -> closed", c->self);
208 chan_send_oclose1(c);
209 c->ostate = CHAN_OUTPUT_CLOSED;
212 error("channel %d: chan_write_failed for ostate %d",
218 chan_obuf_empty1(Channel *c)
220 debug("channel %d: obuf empty", c->self);
221 if (buffer_len(&c->output)) {
222 error("channel %d: chan_obuf_empty for non empty buffer",
227 case CHAN_OUTPUT_WAIT_DRAIN:
228 debug("channel %d: output drain -> closed", c->self);
229 chan_send_oclose1(c);
230 c->ostate = CHAN_OUTPUT_CLOSED;
233 error("channel %d: internal error: obuf_empty for ostate %d",
239 chan_send_ieof1(Channel *c)
241 debug("channel %d: send ieof", c->self);
243 case CHAN_INPUT_OPEN:
244 case CHAN_INPUT_WAIT_DRAIN:
245 packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
246 packet_put_int(c->remote_id);
250 error("channel %d: cannot send ieof for istate %d",
256 chan_send_oclose1(Channel *c)
258 debug("channel %d: send oclose", c->self);
260 case CHAN_OUTPUT_OPEN:
261 case CHAN_OUTPUT_WAIT_DRAIN:
262 chan_shutdown_write(c);
263 buffer_clear(&c->output);
264 packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
265 packet_put_int(c->remote_id);
269 error("channel %d: cannot send oclose for ostate %d",
279 chan_rcvd_oclose2(Channel *c)
281 debug("channel %d: rcvd close", c->self);
282 if (c->flags & CHAN_CLOSE_RCVD)
283 error("channel %d: protocol error: close rcvd twice", c->self);
284 c->flags |= CHAN_CLOSE_RCVD;
285 if (c->type == SSH_CHANNEL_LARVAL) {
286 /* tear down larval channels immediately */
287 c->ostate = CHAN_OUTPUT_CLOSED;
288 c->istate = CHAN_INPUT_CLOSED;
292 case CHAN_OUTPUT_OPEN:
294 * wait until a data from the channel is consumed if a CLOSE
297 debug("channel %d: output open -> drain", c->self);
298 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
302 case CHAN_INPUT_OPEN:
303 debug("channel %d: input open -> closed", c->self);
304 chan_shutdown_read(c);
306 case CHAN_INPUT_WAIT_DRAIN:
307 debug("channel %d: input drain -> closed", c->self);
311 c->istate = CHAN_INPUT_CLOSED;
314 chan_ibuf_empty2(Channel *c)
316 debug("channel %d: ibuf empty", c->self);
317 if (buffer_len(&c->input)) {
318 error("channel %d: chan_ibuf_empty for non empty buffer",
323 case CHAN_INPUT_WAIT_DRAIN:
324 debug("channel %d: input drain -> closed", c->self);
325 if (!(c->flags & CHAN_CLOSE_SENT))
327 c->istate = CHAN_INPUT_CLOSED;
330 error("channel %d: chan_ibuf_empty for istate %d",
336 chan_rcvd_ieof2(Channel *c)
338 debug("channel %d: rcvd eof", c->self);
339 if (c->ostate == CHAN_OUTPUT_OPEN) {
340 debug("channel %d: output open -> drain", c->self);
341 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
345 chan_write_failed2(Channel *c)
347 debug("channel %d: write failed", c->self);
349 case CHAN_OUTPUT_OPEN:
350 debug("channel %d: output open -> closed", c->self);
351 chan_shutdown_write(c); /* ?? */
352 c->ostate = CHAN_OUTPUT_CLOSED;
354 case CHAN_OUTPUT_WAIT_DRAIN:
355 debug("channel %d: output drain -> closed", c->self);
356 chan_shutdown_write(c);
357 c->ostate = CHAN_OUTPUT_CLOSED;
360 error("channel %d: chan_write_failed for ostate %d",
366 chan_obuf_empty2(Channel *c)
368 debug("channel %d: obuf empty", c->self);
369 if (buffer_len(&c->output)) {
370 error("channel %d: chan_obuf_empty for non empty buffer",
375 case CHAN_OUTPUT_WAIT_DRAIN:
376 debug("channel %d: output drain -> closed", c->self);
377 chan_shutdown_write(c);
378 c->ostate = CHAN_OUTPUT_CLOSED;
381 error("channel %d: chan_obuf_empty for ostate %d",
387 chan_send_eof2(Channel *c)
389 debug("channel %d: send eof", c->self);
391 case CHAN_INPUT_WAIT_DRAIN:
392 packet_start(SSH2_MSG_CHANNEL_EOF);
393 packet_put_int(c->remote_id);
397 error("channel %d: cannot send eof for istate %d",
403 chan_send_close2(Channel *c)
405 debug("channel %d: send close", c->self);
406 if (c->ostate != CHAN_OUTPUT_CLOSED ||
407 c->istate != CHAN_INPUT_CLOSED) {
408 error("channel %d: cannot send close for istate/ostate %d/%d",
409 c->self, c->istate, c->ostate);
410 } else if (c->flags & CHAN_CLOSE_SENT) {
411 error("channel %d: already sent close", c->self);
413 packet_start(SSH2_MSG_CHANNEL_CLOSE);
414 packet_put_int(c->remote_id);
416 c->flags |= CHAN_CLOSE_SENT;
423 chan_mark_dead(Channel *c)
425 c->type = SSH_CHANNEL_ZOMBIE;
429 chan_is_dead(Channel *c, int send)
431 if (c->type == SSH_CHANNEL_ZOMBIE) {
432 debug("channel %d: zombie", c->self);
435 if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
438 debug("channel %d: is dead", c->self);
442 * we have to delay the close message if the efd (for stderr) is
445 if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
446 buffer_len(&c->extended) > 0)
448 || ((c->extended_usage == CHAN_EXTENDED_READ) &&
452 debug2("channel %d: active efd: %d len %d type %s",
453 c->self, c->efd, buffer_len(&c->extended),
454 c->extended_usage==CHAN_EXTENDED_READ ?
457 if (!(c->flags & CHAN_CLOSE_SENT)) {
461 /* channel would be dead if we sent a close */
462 if (c->flags & CHAN_CLOSE_RCVD) {
463 debug("channel %d: almost dead",
469 if ((c->flags & CHAN_CLOSE_SENT) &&
470 (c->flags & CHAN_CLOSE_RCVD)) {
471 debug("channel %d: is dead", c->self);
479 chan_init_iostates(Channel *c)
481 c->ostate = CHAN_OUTPUT_OPEN;
482 c->istate = CHAN_INPUT_OPEN;
491 chan_rcvd_oclose = chan_rcvd_oclose2;
492 chan_read_failed = chan_read_failed_12;
493 chan_ibuf_empty = chan_ibuf_empty2;
495 chan_rcvd_ieof = chan_rcvd_ieof2;
496 chan_write_failed = chan_write_failed2;
497 chan_obuf_empty = chan_obuf_empty2;
499 chan_rcvd_oclose = chan_rcvd_oclose1;
500 chan_read_failed = chan_read_failed_12;
501 chan_ibuf_empty = chan_ibuf_empty1;
503 chan_rcvd_ieof = chan_rcvd_ieof1;
504 chan_write_failed = chan_write_failed1;
505 chan_obuf_empty = chan_obuf_empty1;
511 chan_shutdown_write(Channel *c)
513 buffer_clear(&c->output);
514 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
516 /* shutdown failure is allowed if write failed already */
517 debug("channel %d: close_write", c->self);
519 if (shutdown(c->sock, SHUT_WR) < 0)
520 debug("channel %d: chan_shutdown_write: "
521 "shutdown() failed for fd%d: %.100s",
522 c->self, c->sock, strerror(errno));
524 if (channel_close_fd(&c->wfd) < 0)
525 log("channel %d: chan_shutdown_write: "
526 "close() failed for fd%d: %.100s",
527 c->self, c->wfd, strerror(errno));
531 chan_shutdown_read(Channel *c)
533 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
535 debug("channel %d: close_read", c->self);
538 * shutdown(sock, SHUT_READ) may return ENOTCONN if the
539 * write side has been closed already. (bug on Linux)
540 * HP-UX may return ENOTCONN also.
542 if (shutdown(c->sock, SHUT_RD) < 0
543 && errno != ENOTCONN)
544 error("channel %d: chan_shutdown_read: "
545 "shutdown() failed for fd%d [i%d o%d]: %.100s",
546 c->self, c->sock, c->istate, c->ostate,
549 if (channel_close_fd(&c->rfd) < 0)
550 log("channel %d: chan_shutdown_read: "
551 "close() failed for fd%d: %.100s",
552 c->self, c->rfd, strerror(errno));