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 1.36 2002/01/10 12:47:59 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);
159 case CHAN_OUTPUT_OPEN:
160 debug("channel %d: output open -> drain", c->self);
161 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
163 case CHAN_OUTPUT_WAIT_IEOF:
164 debug("channel %d: output wait_ieof -> closed", c->self);
165 c->ostate = CHAN_OUTPUT_CLOSED;
168 error("channel %d: protocol error: rcvd_ieof for ostate %d",
174 chan_write_failed1(Channel *c)
176 debug("channel %d: write failed", c->self);
178 case CHAN_OUTPUT_OPEN:
179 debug("channel %d: output open -> wait_ieof", c->self);
180 chan_send_oclose1(c);
181 c->ostate = CHAN_OUTPUT_WAIT_IEOF;
183 case CHAN_OUTPUT_WAIT_DRAIN:
184 debug("channel %d: output wait_drain -> closed", c->self);
185 chan_send_oclose1(c);
186 c->ostate = CHAN_OUTPUT_CLOSED;
189 error("channel %d: chan_write_failed for ostate %d",
195 chan_obuf_empty1(Channel *c)
197 debug("channel %d: obuf empty", c->self);
198 if (buffer_len(&c->output)) {
199 error("channel %d: chan_obuf_empty for non empty buffer",
204 case CHAN_OUTPUT_WAIT_DRAIN:
205 debug("channel %d: output drain -> closed", c->self);
206 chan_send_oclose1(c);
207 c->ostate = CHAN_OUTPUT_CLOSED;
210 error("channel %d: internal error: obuf_empty for ostate %d",
216 chan_send_ieof1(Channel *c)
218 debug("channel %d: send ieof", c->self);
220 case CHAN_INPUT_OPEN:
221 case CHAN_INPUT_WAIT_DRAIN:
222 packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
223 packet_put_int(c->remote_id);
227 error("channel %d: cannot send ieof for istate %d",
233 chan_send_oclose1(Channel *c)
235 debug("channel %d: send oclose", c->self);
237 case CHAN_OUTPUT_OPEN:
238 case CHAN_OUTPUT_WAIT_DRAIN:
239 chan_shutdown_write(c);
240 buffer_clear(&c->output);
241 packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
242 packet_put_int(c->remote_id);
246 error("channel %d: cannot send oclose for ostate %d",
256 chan_rcvd_oclose2(Channel *c)
258 debug("channel %d: rcvd close", c->self);
259 if (c->flags & CHAN_CLOSE_RCVD)
260 error("channel %d: protocol error: close rcvd twice", c->self);
261 c->flags |= CHAN_CLOSE_RCVD;
262 if (c->type == SSH_CHANNEL_LARVAL) {
263 /* tear down larval channels immediately */
264 c->ostate = CHAN_OUTPUT_CLOSED;
265 c->istate = CHAN_INPUT_CLOSED;
269 case CHAN_OUTPUT_OPEN:
271 * wait until a data from the channel is consumed if a CLOSE
274 debug("channel %d: output open -> drain", c->self);
275 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
279 case CHAN_INPUT_OPEN:
280 debug("channel %d: input open -> closed", c->self);
281 chan_shutdown_read(c);
283 case CHAN_INPUT_WAIT_DRAIN:
284 debug("channel %d: input drain -> closed", c->self);
288 c->istate = CHAN_INPUT_CLOSED;
291 chan_ibuf_empty2(Channel *c)
293 debug("channel %d: ibuf empty", c->self);
294 if (buffer_len(&c->input)) {
295 error("channel %d: chan_ibuf_empty for non empty buffer",
300 case CHAN_INPUT_WAIT_DRAIN:
301 debug("channel %d: input drain -> closed", c->self);
302 if (!(c->flags & CHAN_CLOSE_SENT))
304 c->istate = CHAN_INPUT_CLOSED;
307 error("channel %d: chan_ibuf_empty for istate %d",
313 chan_rcvd_ieof2(Channel *c)
315 debug("channel %d: rcvd eof", c->self);
316 if (c->ostate == CHAN_OUTPUT_OPEN) {
317 debug("channel %d: output open -> drain", c->self);
318 c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
322 chan_write_failed2(Channel *c)
324 debug("channel %d: write failed", c->self);
326 case CHAN_OUTPUT_OPEN:
327 debug("channel %d: output open -> closed", c->self);
328 chan_shutdown_write(c); /* ?? */
329 c->ostate = CHAN_OUTPUT_CLOSED;
331 case CHAN_OUTPUT_WAIT_DRAIN:
332 debug("channel %d: output drain -> closed", c->self);
333 chan_shutdown_write(c);
334 c->ostate = CHAN_OUTPUT_CLOSED;
337 error("channel %d: chan_write_failed for ostate %d",
343 chan_obuf_empty2(Channel *c)
345 debug("channel %d: obuf empty", c->self);
346 if (buffer_len(&c->output)) {
347 error("channel %d: chan_obuf_empty for non empty buffer",
352 case CHAN_OUTPUT_WAIT_DRAIN:
353 debug("channel %d: output drain -> closed", c->self);
354 chan_shutdown_write(c);
355 c->ostate = CHAN_OUTPUT_CLOSED;
358 error("channel %d: chan_obuf_empty for ostate %d",
364 chan_send_eof2(Channel *c)
366 debug("channel %d: send eof", c->self);
368 case CHAN_INPUT_WAIT_DRAIN:
369 packet_start(SSH2_MSG_CHANNEL_EOF);
370 packet_put_int(c->remote_id);
374 error("channel %d: cannot send eof for istate %d",
380 chan_send_close2(Channel *c)
382 debug("channel %d: send close", c->self);
383 if (c->ostate != CHAN_OUTPUT_CLOSED ||
384 c->istate != CHAN_INPUT_CLOSED) {
385 error("channel %d: cannot send close for istate/ostate %d/%d",
386 c->self, c->istate, c->ostate);
387 } else if (c->flags & CHAN_CLOSE_SENT) {
388 error("channel %d: already sent close", c->self);
390 packet_start(SSH2_MSG_CHANNEL_CLOSE);
391 packet_put_int(c->remote_id);
393 c->flags |= CHAN_CLOSE_SENT;
400 chan_mark_dead(Channel *c)
402 c->type = SSH_CHANNEL_ZOMBIE;
406 chan_is_dead(Channel *c, int send)
408 if (c->type == SSH_CHANNEL_ZOMBIE) {
409 debug("channel %d: zombie", c->self);
412 if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
415 debug("channel %d: is dead", c->self);
419 * we have to delay the close message if the efd (for stderr) is
422 if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
423 buffer_len(&c->extended) > 0)
425 || ((c->extended_usage == CHAN_EXTENDED_READ) &&
429 debug2("channel %d: active efd: %d len %d type %s",
430 c->self, c->efd, buffer_len(&c->extended),
431 c->extended_usage==CHAN_EXTENDED_READ ?
434 if (!(c->flags & CHAN_CLOSE_SENT)) {
438 /* channel would be dead if we sent a close */
439 if (c->flags & CHAN_CLOSE_RCVD) {
440 debug("channel %d: almost dead",
446 if ((c->flags & CHAN_CLOSE_SENT) &&
447 (c->flags & CHAN_CLOSE_RCVD)) {
448 debug("channel %d: is dead", c->self);
456 chan_init_iostates(Channel *c)
458 c->ostate = CHAN_OUTPUT_OPEN;
459 c->istate = CHAN_INPUT_OPEN;
468 chan_rcvd_oclose = chan_rcvd_oclose2;
469 chan_read_failed = chan_read_failed_12;
470 chan_ibuf_empty = chan_ibuf_empty2;
472 chan_rcvd_ieof = chan_rcvd_ieof2;
473 chan_write_failed = chan_write_failed2;
474 chan_obuf_empty = chan_obuf_empty2;
476 chan_rcvd_oclose = chan_rcvd_oclose1;
477 chan_read_failed = chan_read_failed_12;
478 chan_ibuf_empty = chan_ibuf_empty1;
480 chan_rcvd_ieof = chan_rcvd_ieof1;
481 chan_write_failed = chan_write_failed1;
482 chan_obuf_empty = chan_obuf_empty1;
488 chan_shutdown_write(Channel *c)
490 buffer_clear(&c->output);
491 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
493 /* shutdown failure is allowed if write failed already */
494 debug("channel %d: close_write", c->self);
496 if (shutdown(c->sock, SHUT_WR) < 0)
497 debug("channel %d: chan_shutdown_write: "
498 "shutdown() failed for fd%d: %.100s",
499 c->self, c->sock, strerror(errno));
501 if (channel_close_fd(&c->wfd) < 0)
502 log("channel %d: chan_shutdown_write: "
503 "close() failed for fd%d: %.100s",
504 c->self, c->wfd, strerror(errno));
508 chan_shutdown_read(Channel *c)
510 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
512 debug("channel %d: close_read", c->self);
515 * shutdown(sock, SHUT_READ) may return ENOTCONN if the
516 * write side has been closed already. (bug on Linux)
517 * HP-UX may return ENOTCONN also.
519 if (shutdown(c->sock, SHUT_RD) < 0
520 && errno != ENOTCONN)
521 error("channel %d: chan_shutdown_read: "
522 "shutdown() failed for fd%d [i%d o%d]: %.100s",
523 c->self, c->sock, c->istate, c->ostate,
526 if (channel_close_fd(&c->rfd) < 0)
527 log("channel %d: chan_shutdown_read: "
528 "close() failed for fd%d: %.100s",
529 c->self, c->rfd, strerror(errno));